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The Effects of Irrigation on Revegetation of Semi-Arid Coastal Sage Scrub in Southern California.

/ To test the appropriateness and applicability of irrigation for restoration of coastal sage scrub, a semi-arid vegetation type native to southern California, a field study comparing four irrigation schedules-no irrigation, spring irrigation only, summer irrigation only, and irrigation year round as needed-was established. A seed mixture of six native shrub species was broadcast, and the effect of irrigation on emergence and establishment was evaluated. Restoration of arid and semi-arid vegetation is challenging because of the severe environmental conditions inherent to these ecosystems. In particular, the low and unpredictable nature of precipitation can limit the chances for successful establishment of perennial species. Under conditions where supplemental irrigation is available, irrigation may make the difference between successful or failed restoration. However, increasing the availability of water through irrigation may result in poor plant adaptation to surviving arid conditions or only temporary success followed by failure once supplemental water is withdrawn. In this study, irrigation stimulated germination in the irrigated plots about a month earlier than the plots dependent on natural rainfall, but this had little lasting effect. Spring and summer irrigation did not improve survival compared to the plots receiving no supplemental water. The largest effect of irrigation was a reduction in survival of several species grown under irrigated conditions as compared to nonirrigated conditions. In plots where water was applied all year long a single species, Artemisia californica, represented nearly 100% of the species present at the end of two growing seasons. Irrigation may speed revegetation under some conditions, but was not very effective in establishing natural vegetation structure.

Journal Article↗

Physiological mechanisms contributing to the increased water-use efficiency in winter wheat under deficit irrigation.

Deficit irrigation in winter wheat has been practiced in the areas with limited irrigation water resources. The objectives of this study were to (i) understand the physiological basis for determinations of grain yield and water-use efficiency in grain yield (WUE) under deficit irrigation; and (ii) investigate the effect of deficit irrigation on dry matter accumulation and remobilization of pre-anthesis carbon reserves during grain filling. A field experiment was conducted in the Southern High Plains of the USA and winter wheat (cv. TAM 202) was grown on Pullman clay loam soil (fine mixed thermic Torretic Paleustoll). Treatments consisted of rain-fed, deficit irrigation from jointing to the middle of grain filling, and full irrigation. The physiological measurements included leaf water potential, net photosynthetic rate (Pn), stomatal conductance (Gs), and leaf area index. The rain-fed treatment had the lowest seasonal evapotranspiration (ET), biomass, grain yield, harvest index (HI) and WUE as a result of moderate to severe water stress from jointing to grain filling. Irrigation application increased seasonal ET, and ET increased as irrigation frequency increased. The seasonal ET increased 20% in one-irrigation treatments between jointing and anthesis, 32-46% in two-irrigation treatments, and 67% in three- and full irrigation treatments. Plant biomass, grain yield, HI and WUE increased as the result of increased ET. The increased yield under irrigation was mainly contributed by the increased number of spikes, and seeds per square meter and per spike. Among the irrigation treatments, grain yield increased significantly but the WUE increased slightly as irrigation frequency increased. The increased WUE under deficit irrigation was contributed by increased HI. Water stress during grain filling reduced Pn and Gs, and accelerated leaf senescence. However, the water stress during grain filling induced remobilization of pre-anthesis carbon reserves to grains, and the remobilization of pre-anthesis carbon reserves significantly contributed to the increased grain yield and HI. The results of this study showed that deficit irrigation between jointing and anthesis significantly increased wheat yield and WUE through increasing both current photosynthesis and the remobilization of pre-anthesis carbon reserves.

Adaptation, Physiological↗

Clinical value of colonic irrigation in patients with continence disturbances.

UNLABELLED: Continence disturbances, especially fecal soiling, are difficult to treat. Irrigation of the distal part of the large bowel might be considered as a nonsurgical alternative for patients with impaired continence. PURPOSE: This study is aimed at evaluating the clinical value of colonic irrigation. METHODS: Thirty-two patients (16 females; median age, 47 (range, 23-72) years) were offered colonic irrigation on an ambulatory basis. Sixteen patients suffered from fecal soiling (Group I), whereas the other 16 patients were treated for fecal incontinence (Group II). Patients were instructed by enterostomal therapists how to use a conventional colostomy irrigation set to obtain sufficient irrigation of the distal part of their large bowel. Patients with continence disturbances during the daytime were instructed to introduce 500 to 1,000 ml of warm (38 degrees C) water within 5 to 10 minutes after they passed their first stool. In addition, they were advised to wait until the urge to defecate was felt. Patients with soiling during overnight sleep were advised to irrigate during the evening. To determine clinical outcome, a detailed questionnaire was used. RESULTS: Median duration of follow-up was 18 months. Ten patients discontinued irrigation within the first month of treatment. Symptoms resolved completely in two patients. They believed that there was no need to continue treatment any longer. Irrigation had no effect in two patients. Despite the fact that symptoms resolved, six patients discontinued treatment because they experienced pain (n = 2) or they considered the irrigation to be too time-consuming (n = 4). Twenty-two patients are still performing irrigations. Most patients irrigated the colon in the morning after the first stool was passed. Time needed for washout varied between 10 and 90 minutes. Frequency of irrigations varied from two times per day to two times per week. In Group I, irrigation was found to be beneficial in 92 percent of patients, whereas 60 percent of patients in Group II considered the treatment as a major improvement to the quality of their lives. If patients who discontinued treatment because of washout-related problems are included in the assessment of final outcome, the success rate is 79 and 38 percent respectively. CONCLUSIONS: Patients with fecal soiling benefit more from colonic irrigation than patients with incontinence for liquid or solid stools. If creation of a stoma is considered, especially in patients with intractable and disabling soiling, it might be worthwhile to treat these patients first by colonic irrigation.

Adult↗

Comparison of bulb syringe and pulsed lavage irrigation with use of a bioluminescent musculoskeletal wound model.

BACKGROUND: Despite the fact that wound irrigation is a common surgical procedure, there are many variables, including delivery device, irrigant type, and fluid volume, that have yet to be optimized. The purpose of this study was to compare, with use of transgenic bioluminescent bacteria and standard quantitative microbiological methods, the efficacy of pulsed lavage and bulb syringe irrigation in reducing wound bacterial counts. METHODS: A caprine model of a complex, contaminated musculoskeletal wound was developed with use of a bioluminescent strain of Pseudomonas aeruginosa that can be quantified. Luminescent activity was recorded as relative luminescent units with use of a photon-counting camera six hours after the wound was created and inoculated. Twelve goats were randomly assigned to either the pulsed lavage group or the bulb syringe irrigation group. Each wound was irrigated with normal saline solution in 3-L increments for a total of 9 L and was imaged after each 3-L increment. In addition, quantitative culture samples were obtained from different tissues within the wound before and after irrigation. RESULTS: Pulsed lavage decreased the amount of relative luminescent units by 52%, 64%, and 70% at 3, 6, and 9 L, respectively. The bulb syringe irrigation reduced the amount of relative luminescent units by 33%, 44%, and 51% at these same time-points. Significant differences in luminescence were noted between the two groups after both 6 and 9 L of irrigation (p < or = 0.04). The correlation coefficients between relative luminescent units and quantitative cultures for the condition before irrigation and after irrigation were r = 0.96 and 0.83, respectively. CONCLUSIONS: Pulsed lavage was more effective than bulb syringe irrigation in reducing bacterial luminescence after both 6 and 9 L of irrigation. Both device and volume effects can be demonstrated with use of this model. Bioluminescent bacteria provide a method to visualize bacterial distribution and to quantify the bacteria in a wound. CLINICAL RELEVANCE: Pulsed lavage is a more effective and efficient method of irrigation to remove bacteria in a complex musculoskeletal wound. In the model we used, pulsed lavage irrigation with 3 L of saline solution resulted in a reduction of approximately the same amount of bacteria as did irrigation with 9 L with use of a bulb syringe.

Animals↗

Socio-economic, health and nutritional status of the villagers in the Nong Wai irrigation area, Khon Kaen, Northeast Thailand.

Studies were carried out from June 1974 to May 1975 on the socio-economic status, health and nutritional status of the people in 4 villages, in the irrigation area of the Nong Wai Pioneer Agricultural Project of Khon Kaen Province, Northeast Thailand. The result obtained were compared with those in 2 non-irrigated villages in the same province, in order to identify the health and nutritional problems which might arise during the water resource development in the irrigation area. It was found that in the irrigated villages 90% of the peoples were farmers, while in the non-irrigated villages all were farmers. The socio-economic status of the people in the irrigated villages was much better than those in the non-irrigated ones. The income per family in the former was about three times greater than that in the latter. In the study of the health conditions of the villagers, the vulnerable age group including pre-school children under 7 years of age and school children in the elementary school class 1 and class 2, aged 7-9 years old, served as subjects for investigation. Haematological and physical examinations revealed many children with mild to moderate anaemia, vitamin B2 deficiency and a few cases of hepatomegaly. Anaemic children were found to be more prevalent in the non-irrigated villages than in the irrigated area. The overall parasitic infection rates in children in the irrigated and non-irrigated villages were similar with respect to severity of the infection. Hookworm infection, opisthorchiasis, strongyloidiasis and giardiasis were the leading parasitic infections, while amoebiasis was rare. Ascariasis and trichuriasis were not found. However, the first two helminthic infections had a low grade of intensity. The nutritional status of pre-school children, showed that there were more children with good growth in the irrigated villages than in the non-irrigated one. Serum proteins, albumin and globulin, and urinary urea nitrogen-creatinine ratio revealed normal findings indicating that the children had sufficient protein intake. The results of the urinary hydroxyproline-creatinine index suggested that many of the children in both groups of the villages were at marginal malnutrition status. Surveys on domestic animals including cattle, buffaloes, pigs, and field rats revealed no important zoonotic diseases except leptospirosis in a few rats. Some fish were found to harbour metacercariae of Opisthorchis viverrini, while some snails were positive for cercariae of O. viverrini, Schistosoma spindale, and Echinostoma malayanum. The overall findings indicated that the water resource development by establishing better irrigation, resulted in an improved socio-economic and nutritional status among the villagers, but health conditions and associated parasitic diseases and some nutritional deficiency still existed in the children. However, the findings from this study provide only preliminary data concerning the socio-economic status, health, and nutritional status of the villagers in the irrigation area...

Adolescent↗

Peritoneal irrigation with povidone-iodine solution after laparoscopic-assisted splenectomy significantly decreases port-tumor recurrence in a murine model.

PURPOSE: The development of port-wound tumor recurrences has raised questions regarding the safety of laparoscopic methods for the resection of malignancies. The cause and the incidence of abdominal-wall tumor recurrences remain unknown. It is also not clear how to avoid or lower the incidence of port-tumor recurrences. The purpose of the current study was to determine the impact of abdominal irrigation with povidone-iodine on the port-wound tumor incidence in a murine model. METHODS: A splenic tumor model was used for this study. To establish splenic tumors, female BALB/c mice (N = 48) were given subcapsular splenic injections of a 0.1 ml suspension containing 10(5) C-26 colon adenocarcinoma cells via a left-flank incision at the initial procedure. Seven days later, the animals with isolated splenic tumors (100 percent) were randomly assigned to one of three groups: 1) control, 2) saline irrigation (saline), or 3) povidone-iodine irrigation. All animals underwent laparoscopic mobilization of the spleen using a three-port technique, intra-abdominal crushing of the tumor, followed by an extracorporeal splenectomy via a subcostal incision. No irrigation was performed for control group animals. In the saline irrigation group, the subcostal incision was closed and pneumoperitoneum was re-established. The abdominal cavity was irrigated with 5 ml of normal saline for 60 seconds before instrument removal. In the povidone-iodine irrigation group, similar abdominal irrigation was performed, using 0.25 percent povidone-iodine. Attempts were made to recover completely the irrigation for both irrigation groups. Seven days after the splenectomy, animals were killed and inspected for abdominal-wall tumor implants. RESULTS: There were significantly more animals with at least one port-tumor recurrence in the control group than in the povidone-iodine group (P = 0.007). Although not statistically significant, the number of animals with port-wound tumors was higher in the saline group than in the povidone-iodine group (P < 0.08). There was no significant difference between the saline group and the control group. When each port site was considered independently, the incidence of port-wound tumors (number of ports with tumors per total number of ports) was significantly lower in the povidone-iodine group than in both the control (P = 0.00001) and saline groups (P = 0.03). The incidence of port-wound tumors was also significantly lower in the saline group compared with the control group incidence (P = 0.03). CONCLUSIONS: Abdominal irrigation with dilute povidone-iodine solution significantly reduced the number of animals with port-tumor recurrences. Abdominal irrigation with saline was also effective in reducing the incidence of port-wound tumor formation when each port was considered separately. However, povidone-iodine irrigation was much more effective than saline irrigation in preventing port-wound tumor formation.

Adenocarcinoma↗

Comparison of castile soap, benzalkonium chloride, and bacitracin as irrigation solutions for complex contaminated orthopaedic wounds.

OBJECTIVE: The purpose of the present study was to determine the effects of cleaning a contaminated orthopaedic wound with different classes of wound irrigation solutions. STUDY DESIGN: Rats with a contaminated orthopaedic wound were randomized into treatment groups: normal saline (NS), castile soap (CS), benzalkonium chloride (BzC), bacitracin (Abx), or sequential irrigation with BzC, CS, and NS. INTERVENTION: Pseudomonas aeruginosa [P. aeruginosa; 1 x 10(6) colony-forming units (CFU)], or Staphylococcus aureus (S. aureus; 1 x 10(6) CFU) were placed into a paravertebral wound (containing a wire implant placed through a spinous process) and allowed to incubate for fifteen minutes. The wound was then irrigated with three liters of either NS, 0.05 percent CS, 0.03 percent BzC, Abx (33,000 units per liter) or underwent a sequential irrigation treatment (one liter each of BzC, CS, NS). MAIN OUTCOME MEASUREMENTS: The animals were observed daily for wound complications for fourteen days and then killed, and cultures of the wound were obtained. RESULTS: Pseudomonas aeruginosa: Both CS and the sequential irrigation treatment significantly lowered the rate of positive wound cultures when compared with NS (p < 0.05). Irrigation with BzC resulted in a higher rate of positive wound cultures and complications. The sequential irrigation treatment prevented the wound complications associated with irrigation with BzC alone. Staphylococcus aureus: Only BzC irrigation significantly lowered the rate of positive wound cultures when compared with NS (p < 0.05). CONCLUSION: The rate of positive wound cultures due to P. aeruginosa is effectively reduced by irrigation with CS alone or by the sequential irrigation treatment. When used alone, the antiseptic BzC results in a higher rate of positive wound cultures and wound complications. The wound complications seen with irrigation with BzC alone are prevented by the sequential irrigation treatment (BzC followed by CS and NS). The rate of positive wound cultures in this model due to S. aureus is not decreased by irrigation with CS; however, the rate of positive wound cultures is safely and effectively decreased with the use of BzC.

Animals↗

Radiographic comparison of three methods for nasal saline irrigation.

OBJECTIVE: To compare intranasal distribution of saline solution delivered by three popular methods for nasal saline irrigation. STUDY DESIGN: Prospective, controlled comparison. METHODS: Eight healthy adult volunteers received nasal irrigation with 40 mL of isotonic, nonionic contrast material immediately before having coronal computed tomography to visualize distribution of solution in the paranasal sinuses. For each study subject, three methods of irrigation were used: irrigation using positive-pressure irrigation, irrigation using negative-pressure irrigation, and irrigation using a nebulizer. For each subject, three-dimensional computer reconstructions of the irrigated paranasal sinus airspaces were used to compare contrast solution volume and distribution achieved by the three methods. RESULTS: Of the three methods used, two methods, positive-pressure and negative-pressure irrigation, distributed contrast solution widely to ethmoid and maxillary sinuses, but distribution of contrast solution was more uniform using positive-pressure irrigation than using negative-pressure irrigation. The nebulization method distributed contrast solution poorly and resulted in a significantly lower volume of retained contrast solution (P <.05). CONCLUSION: Judged solely on the basis of solution distribution in the nasal sinuses, nasal irrigation is effective when either positive-pressure or negative-pressure irrigation is used but is ineffective when a nebulizer is used.

Adult↗

Adjunctive supragingival irrigation with acetylsalicylic acid in periodontal supportive therapy.

To assess the clinical efficacy of adjunctive supragingival irrigation with buffered 0.3% acetylsalicylic acid (ASA), 60 patients with periodontitis receiving supportive periodontal therapy were randomly assigned to 1 of 3 home regimens: (1) 1x daily adjunctive supragingival irrigation with 300 ml water immediately followed by 200 ml of buffered 0.3% ASA; (2) 1x daily adjunctive supragingival irrigation with 500 ml water; or (3) normal oral hygiene alone. Clinical parameters were assessed at baseline and 6 months. Irrigator use was measured by timers built into the irrigator units. Results at 6 months showed that both supragingival irrigation with buffered 0.3% ASA and supragingival irrigation with water significantly reduced gingival index scores (median 0.1 and 0.35, respectively) and pocket probing depths (both median 0.26 mm) compared to the control group. In addition, irrigation with water resulted in a significant reduction in bleeding on probing (median 0.13), whereas irrigation with buffered 0.3% ASA had no significant effect on bleeding on probing compared to the control group. The clinical efficacy of irrigation with either ASA or water was found to be positively correlated to initial disease severity and irrigator use. Thus, frequent supragingival irrigation with either 0.3% ASA or water in addition to regular oral hygiene appears to be a beneficial adjunct to periodontal supportive therapy in patients with moderate to severe signs of periodontitis. However, the use of buffered 0.3% ASA as an irrigant does not seem to enhance the clinical efficacy of supragingival irrigation on periodontal health.

Adult↗

Intraoperative saline and gemcitabine irrigation improves tumour control in human squamous cell carcinoma-contaminated surgical wounds.

INTRODUCTION AND OBJECTIVES: The cure rates for advanced head and neck cancer patients have not changed substantially in the past few decades. Most disease recurrences are local or regional and are likely due to residual microscopic disease or intraoperative wound contamination. We developed a murine model of wound implantation with microscopic disease to assess the efficiency of tumour development and used this model to evaluate the effects on tumour development of surgical bed irrigation with three different solutions. METHODS: Nonobese diabetic/severe combined immunodeficient mice were transplanted with the University of Michigan squamous cell carcinoma-22B cells derived from a human squamous cell carcinoma of the hypopharynx. Two 1-cm surgical wounds were created on the backs of 20 mice and then instilled with a known quantity of tumour cells. The minimum necessary dose to reliably result in tumour growth was then determined. Forty mice were then inoculated with this minimum tumour concentration. Ten of these mice had their incisions closed immediately and were kept as controls. Ten of the mice had their wounds irrigated with 5 cc of water and then closed, 10 had their wounds irrigated with 5 cc of saline and then closed, and 10 had their wounds irrigated with 5 cc of 1-mM gemcitabine, a nonirritating chemotherapy drug with activity in human head and neck cancers. The mice were then observed for the development of palpable tumours. RESULTS: We were unable to successfully grow tumours in any wounds that were seeded with less than 2.5 x 10(6) cells. After exposure to 2.5 x 10(6) cells, seven of eight surgical beds developed palpable tumours. This was then taken as our standard inoculation dose. All of the study mice wounds healed rapidly irrespective of irrigation solution. At postoperative day 17, 70% of the controls had evident tumour growth, whereas only 15% of the water irrigation group (p < .0005), 0% of the saline irrigation group (p < .0001), and 0% (p < .0001) of the gemcitabine irrigation group had developed tumours. By day 24, the disease recurrence rates in the water irrigation group no longer differed from controls, whereas the lower incidence of tumour recurrence in the gemcitabine and saline irrigation groups persisted. On day 56, 80% of the control mice and 75% of the water-irrigated mice group had developed palpable tumours. In the saline and gemcitabine groups, however, only 40% (p < .01) and 35% (p < .004), respectively, had evident tumours. CONCLUSIONS: In a xenograft model of tumour-cell wound contamination, irrigation with saline, water, or gemcitabine delayed tumour development. Irrigation with gemcitabine or saline improved rates of long-term disease control. Gemcitabine irrigation did not affect wound healing and was free of local complications.

Animals↗

Impact of irrigation on malaria in Africa: paddies paradox.

The high population growth rate of the African continent has led to an increased demand for food and is in danger of outstripping agricultural production. In order to meet this need, many governments have sought ways of improving food production by initiating large-scale irrigation projects, involving reclamation of arid and semi-arid areas for the cultivation of crops. Although crop irrigation promises one solution to alleviating hunger and encourages economic growth, irrigation has often been blamed for aggravating disease in local communities. Malaria is one of the major tropical diseases associated with irrigation schemes, and changes in the transmission pattern of this disease following irrigation development have been a perennial subject of debate. It has often been assumed that high numbers of malaria vector Anopheles mosquitoes (Diptera: Culicidae) resulting from irrigation schemes lead inevitably to increased malaria in local communities. However, recent studies in Africa have revealed a more complex picture. Increased numbers of vectors following irrigation can lead to increased malaria in areas of unstable transmission, where people have little or no immunity to malaria parasites, such as the African highlands and desert fringes. But for most of sub-Saharan Africa, where malaria is stable, the introduction of crop irrigation has little impact on malaria transmission. Indeed, there is growing evidence that for many sites there is less malaria in irrigated communities than surrounding areas. The explanation for this finding is still unresolved but, in some cases at least, can be attributed to displacement of the most endophilic and anthropophilic malaria vector Anopheles funestus Giles by An. arabiensis Patton with lower vectorial capacity, as the latter thrives more than the former in ricefields. Similarly, among members of the An. gambiae complex, some cytotypes of An. gambiae sensu stricto are more vectorial than others. For example, the Mopti form has high vectorial capacity and breeds perennially in irrigated sites, whereas the savanna form is often sympatric but more seasonal. Also we suggest that many communities near irrigation schemes benefit from the greater wealth created by these schemes. Consequently irrigation communities often have greater use of bednets, better access to improved healthcare and receive fewer infective bites compared with those outside such development schemes. Thus, in most cases, irrigation schemes in Africa do not appear to increase malaria risk, except in areas of unstable transmission. However, developers should take the opportunity to improve health-care facilities for local communities when planning irrigation schemes wherever they occur.

Africa↗

[Multiplication technique of rice T(P) GMS line with double low critical temperature values using cold water irrigation].

In this paper, cold-water irrigation multiplication technique was used to solve the difficulty of multiplying rice TGMS line 96-5-2S(Oryza sative L.) with double low critical temperature values under natural air temperature condition. The results indicated that irrigating rice TGMS line 96-5-2S with different temperature underground cold water from the stage of pistil and stamen primordia differentiation to the stage of pollen filling for 15 days, and keeping the water depth 18-22 cm, the seed set rate of 96-5-2S decreased with increasing irrigating water temperature. When the average temperature of irrigation water was 18.5-19.8 degrees C, the seed set rate ranged from 40.5% to 57.6%, and the yield ranged from 3.30 t.hm-2 to 4.35 t.hm-2. While the temperature was 20.5-21.3 degrees C, the seed set rate and yield sharply decreased to 2.5-10.4% and 0.21-0.90 t.hm-2, respectively. When the average temperature was 22.3-23.5 degrees C, both the seed set rate and yield were zero. Under the same irrigation water temperature (average 19.8 degrees C) and the same irrigating period (phase IV to phase VII), the seed set rate and yield of 96-5-2S with deep water irrigation (18-22 cm) was very significantly higher than those of 96-5-2S with shallow water irrigation (7-10 cm). Under the conditions of same irrigation water temperature (average 19.8 degrees C) and same water depth (18-22 cm) but different irrigating periods (15 days from phase IV to phase VII, 20 days from phase III to phase VII, and 25 days from phase II to phase VII), the difference of seed set rate and yield of 96-5-2S between 15-day treatment and 20-25-day treatment was not significantly different. It is confident that 96-5-2S could multiply with underground cold water irrigation. The main technique index was that irrigating water temperature should be 18-20 degrees C, irrigating period should be from phase IV to phase VII, and irrigating water depth should be 18-22 cm.

Agriculture↗

Effects of surface irrigation on the thermal response of tissue during laser irradiation.

Effects of surface irrigation on the thermal response of tissue during laser irradiation are investigated. In particular, influence of temperature and flow rate of the irrigation fluid on the resulting temperature distributions and coagulation depths are studied. Intraluminal Nd:YAG laser irradiation of bovine muscle is performed in vitro for a fixed value of the irrigation flow rate while the irrigation temperature is varied, and for a fixed irrigation temperature while the irrigation flow rate is kept constant. Thermocouples are used to measure the temperatures within the tissue for various irradiation and irrigation conditions. Higher temperatures and deeper coagulation depths are achieved as the temperature of the irrigation fluid is increased. For sufficiently low values of irradiance and exposure time, the use of cold irrigation is shown to prevent or delay tissue carbonization. Beyond a critical irradiance and an exposure time, use of cold irrigation does not prevent tissue carbonization. Coagulation depths and temperature distributions are not affected by a change in the flow rate of laminar irrigation. Application of stagnant irrigation, however, results in an increase in coagulation depth. Results of this study suggest that the dominating mechanism of heat transfer during application of laminar irrigation is thermal diffusion as compared to the bulk motion of the fluid.

Animals↗

Intrascleral concentration vs depth profile of mitomycin-C after episcleral application: impact of irrigation.

Mitomycin-C has been reported to cause toxic effects on the ciliary body after episcleral application during glaucoma surgery. We investigated the intrascleral diffusion of mitomycin-C in an experimental model. The episcleral sides of scleral quadrants of 14 human donor eyes were exposed for 5 min to sponges (corneal light shield, Merocel corp., Mystic, CT, U.S.A.) soaked with 200 microg ml(-1)mitomycin-C. After the exposure one of four quadrants was not irrigated and the episcleral sides of three quadrants were irrigated with 40, 100 and 200 ml saline. A 9 mm scleral disk was punched out with a trephine and frozen on a kryotome plate 2 min after the end of mitomycin-C exposure. An 8 mm diameter scleral disk was then cut with a trephine, again frozen on a kryotome plate and then horizontally dissected with a kryotome. For analysis purposes seven cuts of 20 microm thickness were combined to one layer of 140 microm. Six layers could be reproduced and were analysed. The mitomycin-C concentrations of these layers were analysed by high-performance liquid chromatography. A concentration vs depth profile was calculated for each group, and the half-width of concentration was calculated by log-linear regression. The mitomycin-C concentration of layer 1 was 24.51 microg g(-1)(+/-7.52) without irrigation, 13.15 microg g(-1)(+/-4.38) after 40 ml irrigation, 10.29 (+/-3.53) after 100 ml irrigation and 8.4 microg g(-1)(+/-1.62) after 200 ml irrigation. In layers 1-3 the concentration of mitomycin-C was significantly reduced by irrigation (ANOVA). In the deeper intrascleral layers irrigation had no effect on the mitomycin-C concentrations. Between layers 2 and 6 the half-width of the mitomycin-C concentration was 101 microm (no-irrigation group), 141 microm (40 ml irrigation group), 153 microm (100 ml irrigation group), and 164 microm (200 ml irrigation group). Irrigation reduced the mitomycin-C concentration only down to half of the scleral thickness, leaving the deep intrascleral concentrations unchanged.

Antibiotics, Antineoplastic↗

Irrigation and drainage properties of three-way urethral catheters.

OBJECTIVES: To evaluate in an in vitro study the irrigation and drainage capabilities of a variety of available catheters. Three-way Foley catheters are used when irrigation of the bladder is anticipated to prevent or manage blood clots in the bladder. METHODS: Six operators applied maximal one-handed pressure irrigation with a catheter-tip syringe through the irrigation and drainage ports of the Bardex and Dover three-way catheters (16F to 26F). Maximal manual irrigation flow was recorded using a flowmeter. Continuous gravity irrigation and drainage flows were measured by suspending a 2-L irrigation bag 80 cm above the catheters and fastening an artificial bladder to the drainage tip of each Foley catheter with the catheter balloon inflated to 30 mL. RESULTS: The Bardex 22F and 24F catheters had superior manual irrigation using the irrigation port (maximal urinary flow rate 8.9 +/- 1.3 mL/s and 9.5 +/- 1.5 mL/s, respectively, P < 0.000001) compared with the Dover 22F and 24F catheters. The Bardex and Dover 22F catheters (maximal urinary flow rate 29.0 +/- 1.9 mL/s and 29.3 +/- 1.9 mL/s, respectively, P = 0.66) and 24F catheters (maximal urinary flow rate 30.5 +/- 2.0 mL/s and 30.6 +/- 1.2 mL/s, respectively, P = 0.83) performed equally in manual irrigation using the drainage port. The Bardex 22F (average flow rate 1.6 +/- 0.1 mL/s, P < 0.00001) and 24F (average flow rate 1.7 +/- 0.0 mL/s, P < 0.000001) catheters exhibited better continuous irrigation and flow than the Dover 22F and 24F catheters. CONCLUSIONS: Three-way catheters are placed in situations in which efficient bladder irrigation is essential for patient safety. The Bardex 22F to 26F catheters optimized continuous bladder irrigation of the catheters tested.

Catheterization↗

Comparison of a new pressurized saline canister versus syringe irrigation for laceration cleansing in the emergency department.

STUDY OBJECTIVE: Studies have documented the efficacy of normal saline irrigation in decreasing wound infection rates. Wounds traditionally are irrigated using a syringe and needle with manual injection of fluid, a time- and labor-intensive method. We compared irrigation times and infection rates for wounds cleansed with syringe irrigation versus a new, single-use canister of pressurized (8 psi) sterile normal saline. DESIGN: Prospective, randomized, controlled. SETTING: Two Level I emergency departments in tertiary care hospitals, both with emergency medicine residency programs. PARTICIPANTS: Patients with lacerations requiring closure were eligible. Exclusion criteria were wounds above the clavicle more than ten hours old, wounds below the clavicle more than six hours old, insulin-dependent diabetes mellitus, or antibiotic or steroid therapy. Patients (550) were entered between August 1, 1990, and January 31, 1991. Characteristics of the two treatment groups were similar for patient age, age of the wound, size and depth of the laceration, and number of sutures. INTERVENTIONS: Lacerations were irrigated with 250 mL saline in a syringe or 220 mL saline in a pressurized canister for each 5 cm of laceration. At follow-up or suture removal, patients were evaluated for signs of wound complications (cellulitis, ascending lymphangitis, purulent discharge, or dehiscence). MAIN RESULTS: The mean irrigation time for the pressurized canister group (281) was 3.9 minutes versus 7.3 minutes in the syringe irrigation group (254) (P < .0001). The complication rate for the pressurized canister group was 5.0% compared with 3.6% for the syringe irrigation group (not significant, P = .50). Only three of the 20 total complications required antibiotics (two in the pressurized canister group, one in the syringe irrigation group). CONCLUSION: Syringe irrigation times were nearly twice as long as the pressurized canister irrigation times. Use of the pressurized canister facilitates ease of irrigation and markedly decreases the time involved in this traditionally labor-intensive activity. In addition, delivery of the saline is no longer operator dependent, ensuring generation of pressures appropriate for wound cleansing. The pressurized canisters may be useful in standardizing irrigation in wound management research.

Adult↗

Periodic subgingival antimicrobial irrigation of periodontal pockets (I). Clinical observations.

The present investigation was undertaken to study the clinical effect of professionally performed periodic subgingival irrigation per se and as an adjunct to scaling and root planing. 10 patients suffering from moderate-severe periodontal disease participated in the study. Following an initial 3-month period of supervised supragingival plaque control, a total of 102 periodontal sites with probing pocket depth greater than or equal to 6 mm and "bleeding on probing" were selected and subjected to a Baseline examination comprising assessments of oral hygiene and gingival conditions, probing depths and probing attachment levels. The pockets in the various jaw quadrants were randomly assigned to one of the following treatment groups: (1) periodic subgingival irrigation with hydrogen peroxide, (2) periodic subgingival irrigation with chlorhexidine, (3) periodic subgingival irrigation with saline and (4) no subgingival treatment. During the first part of the study (baseline-32 weeks), no mechanical debridement of the subgingival area was performed. The irrigation treatment was carried out by the operator 3 times per week during weeks 1 + 2 and 5 + 6 of the trial. In the 2nd part of the trial (32-52 weeks), the sites were subjected to scaling and root planing combined with professional irrigation during weeks 32-38. The previously non-irrigated control sites were not subjected to adjunctive irrigation when mechanically debrided. During the entire study, the patients were recalled for professional tooth cleaning once every 4 weeks. Re-examinations were carried out at 4, 6, 32, 40 and 52 weeks. The results revealed that repeated professional irrigation of unscaled periodontal pockets with chlorhexidine or hydrogen peroxide resulted in a temporarily reduced frequency of bleeding sites, but not in any clinically significant changes in probing assessments. A similar improvement of bleeding scores was observed in the saline-irrigated control group. Scaling and root planing, in combination with an optimal supragingival plaque control, resulted in a marked resolution of the clinical symptoms of periodontal disease. Adjunctive irrigation with chlorhexidine or hydrogen peroxide did not improve the healing result above and beyond that obtained after mechanical debridement alone or in combination with saline irrigation. Hence, the study failed to demonstrate that professionally performed periodic subgingival irrigation with chlorhexidine or hydrogen peroxide, used alone or in combination with thorough mechanical debridement, has a significant therapeutic effect.

Adult↗

Influence of irrigation with lagooned urban wastewater on chemical and microbiological soil parameters in a citrus orchard under Mediterranean condition.

The reduced availability of water resources in semi-arid Mediterranean regions requires an efficient use of supply sources. Urban wastewater, after treatment to minimise health hazards, may constitute an important resource for irrigation in areas characterised by intensive agriculture. These considerations have motivated an investigation (during the irrigation season 1996) of the dynamics of microbial biomass in the soil of a citrus orchard in eastern Sicily, which has been irrigated for 15 years with lagooned urban wastewater, to evaluate the effects of this practice on soil fertility. The analyses of parameters regarding soil microbial biomass (microbial carbon and microbial nitrogen, soluble carbon and nitrogen, cumulative respiration, respiratory quotient and enzymatic activity in the soil) have confirmed that the evolution of soil microflora is directly conditioned by the type of water used for irrigation and climatic conditions. Just before the beginning of the irrigation season (May), microbial biomass carbon (MBC), soluble C, cumulative respiration and enzymatic activity were significantly higher in the soil irrigated with wastewater with respect to the same soil irrigated with 'clear' water; the qCO2 was significantly lower. In June, after 1 month of irrigation, both soils showed an increase of all microbial parameters except for enzymatic activity and qCO2 which showed a significant reduction. In September, at the end of the irrigation period, there was a decrease of almost all investigated parameters in both plots, which was more evident in the soil irrigated with 'clear' water. The microbial biomass of the soil irrigated with wastewater, during the irrigation period, did not undergo any negative effects, having an evolution analogous to the plot irrigated with 'clear' water. The use of lagooned wastewater after three lustrums has shown, particularly in the dry season, an increase in quantity of easily available nutrients, with an improvement of the metabolic efficiency of soil microflora coupled with a more marked activity of total hydrolase and phosphatases. The variations of the parameters related to the soil microflora were strongly influenced by the seasonal climatic trend.

Agriculture↗