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Superovulatory response to a single subcutaneous injection of Folltropin-V in beef cattle.

A series of 4 experiments were designed to evaluate the feasibility of superstimulation in beef cattle with a single sc injection of the porcine pituitary extract, Folltropin-V. In the preliminary study (Experiment 1), superovulatory response of cows (n=7) treated with a single sc injection of 400 mg NIH-FSH-P1 Folltropin-V was not different than that of cows (n=8) superstimulated with twice daily im injections over 4 d, or a single sc injection plus an injection of eCG (n=12). Experiments 2 and 3 were designed to determine the optimal site of a single sc injection. In Experiment 2, cows (n=25) with body condition scores (BCS) of 1 to 2 were used. The mean number of CL counted and ova/embryos collected was lower (P<0.05) in cows treated with the single sc injection in the neck region than in cows treated with a single sc injection behind the shoulder, or with the twice daily im injection treatment. In Experiment 3, cows (n=49) with BCS of 3 to 5 were used. There were no differences in the number of CL, total ova/embrvos collected, fertilized ova and transferable embryos whether treatments were given in the neck region or behind the shoulder, or whether the cows were implanted or not implanted with Syncro-Mate-B. Experiment 4 was designed to determine the optimal superstimulatory dosage of Folltropin-V administered by a single sc injection. Superovulatory response of cows treated with the higher doses (400 mg, 600 mg or 800 mg NIH-FSH-P1) was higher (P<0.05) than those treated with 200 mg NIH-FSH-P1. The number of unovulated (>or=10 mm) follicles at the time of ova/embryo collection was higher (P<0.05) in the 600 and 800 mg groups, and progesterone concentration at estrus was higher (P<0.05) in cows treated with 800 mg than with 400 or 200 mg. It was concluded that a single, bolus sc injection of 400 mg NIH-FSH-P1 of Folltropin-V is as efficacious as the 4-d, twice daily im treatment protocol for inducing superovulation in beef cows. The amount of subcutaneous fat and site of injection appeared to affect the efficacy of a single sc injection; a single bolus sc injection of Folltropin-V behind the shoulder resulted in the most predictable superovulatory response.

Journal Article↗

Injection pressures by anesthesiologists during simulated peripheral nerve block.

BACKGROUND AND OBJECTIVES: Anesthesiologists typically rely on a subjective evaluation ("syringe feel") of possible abnormal resistance to injection while performing a peripheral nerve block (PNB). A greater force required to perform the injection is believed to be associated with intraneural injection. The hypothesis of this study is that anesthesiologists vary in their perception of "normal" injection force, that the syringe feel method is inconsistent in estimating resistance, and that needle design may affect the injection force. METHODS: Thirty anesthesiologists were asked to inject a local anesthetic, as they would in their everyday practice, through a commonly used syringe and needle assembly. Injection force was measured using an in-line manometer coupled to a computer via an analog-to-digital conversion board. In addition, injection force at clinically relevant injection speeds was determined using 3 differently sized needles from 4 different manufacturers. RESULTS: During a steady injection rate, all anesthesiologists perceived an increase in the force required to inject, even with minor pressures changes (0.6 +/- 0.3 psi). However, the 30 anesthesiologists, 21 (70%) initiated injection using a force that resulted in pressures greater than 20 psi; 15 (50%) used a force greater than 25 psi, and 3 (10%) exerted pressures greater than 30 psi. Pressures varied as much as 20-fold among needles of the same gauge/length from different manufacturers (P <.01). CONCLUSIONS: Anesthesiologists vary widely in their perception of appropriate force and rate of injection during PNB. The syringe-feel method of assessing injection force is inconsistent and may be further affected by variability in needle design.

Analysis of Variance↗

Free radical-induced damage in experimental peripheral nerve injection injury.

Peripheral nerve injury secondary to injection of therapeutic agents is well-documented. Until recently, the precise mechanism of injury has been obscure; even today, the treatment of these nerve injection injuries remains controversial. The aim of this study was to determine the involvement of ischemia-reperfusion injury in the development of peripheral nerve injection injury. Wistar rats were randomized into three groups. Sciatic nerve was used as the standardized nerve injection injury model. Two commonly used agents, lidocaine HCl 1 percent and phenol 5 percent, were tested for their comparative effects on the sciatic nerve. Lidocaine and phenol were injected into the sciatic nerves of the rats in Groups 1 and 2, respectively. Physiologic saline was used in the controls (Group 3). All the agents were injected intrafascicularly. The effects of nerve injection injury were assessed by measuring thiobarbituric acid reactive substance (TBARS) levels and obtaining walking-track analyses (WTA). Nerve injection caused significant increases in TBARS levels, which were correlated with the severity of the injury. The TBARS levels were related to the severity of injury caused by the tested agents; TBARS levels in phenol-injected nerves were significantly higher than those of lidocaine-injected nerves. Patterns of alterations in TBARS levels also paralleled the changes in print-length factor. Injection of lidocaine and phenol resulted in near-normal walking tracks at 8 and 12 weeks, respectively, while saline injection caused only transient impairment in walking tracks. These findings indicate that reactive oxygen species are involved in the pathogenesis of experimental peripheral nerve injection injury. Indices of free oxygen radical damage correlate with the progression of functional alterations after nerve injection injury.

Analysis of Variance↗

[Whole-body MR angiography: comparison of two protocols for contrast media injection].

PURPOSE: To compare two injection strategies for contrast media injection in whole-body MR angiography quantitatively and qualitatively with regard to contrast and image quality. MATERIAL AND METHODS: 40 patients were examined at 1.5 Tesla using either a single injection protocol or a double injection protocol with two separate bolus injections. Vessel regions I (supraaortic/thoracic), II (abdominal/pelvic), III (upper legs) and IV (lower legs) were examined in the following order: single injection: I, II, III, IV, double injection: I and IV after the first injection, II and III after the second bolus injection. Quantitative evaluation: SI measurements were carried out in 2 arteries per region. Contrast values were calculated. Qualitative evaluation: Evaluation of regions I-IV regarding vessel contrast, venous overlay and image quality on a five-point scale by two reviewers in consensus. The Mann-Whitney-U test was used to test the differences for significance. RESULTS: Quantitative evaluation: Using the double injection protocol, significantly higher contrast values in regions I and II and significantly lower contrast values in the subregions IIIa (upper part of III) and IVb (lower part of IV) were obtained (p < 0.05). The mean contrast values in subregions IIIb (lower part of III) and IVa (upper part of IV) were lower using the double injection protocol, but not significantly. Qualitative evaluation: Using the double injection protocol, region II was rated significantly higher (mean ratings: 3.55, 3.45 and 3.5 versus 2.7, 2.5 and 2.55; p < 0.05) and region III significantly lower (mean ratings: 3.1, 2, 2.5 versus 3.9, 3.1 and 3.55; p < 0.05) for all three examined criteria. When using the double injection protocol, ratings were significantly lower in region IV regarding vessel contrast and image quality (mean ratings: 2.4 and 2.15 versus 3.45 and 3.15; p < 0.05). The ratings regarding venous overlay in region IV showed no significant differences (mean ratings: 2.15 versus 2.75; p > 0.05). CONCLUSION: Due to the better results in the supraaortic/thoracic and abdominal/pelvic regions, the double injection protocol is preferred. However, both protocols require further improvement.

Adult↗

Drug distribution in the vitreous humor of the human eye: the effects of intravitreal injection position and volume.

PURPOSE: The purpose of this study was to determine how the position and volume of an intravitreal injection affect the distribution and elimination of drug from the vitreous humor. METHODS: A mathematical model that had been developed and used previously to study drug distribution in the vitreous humor of the rabbit eye was modified to match the physiology of the human eye. Fluorescein and fluorescein glucuronide were used as the model compounds for these studies. Four extreme injection locations were considered: a central injection, an injection displaced towards the retina, an injection displaced towards the lens, and an injection displaced toward the hyaloid membrane. Injections containing an equal mass of drug dissolved in volumes of either 15 microL or 100 microL were compared. RESULTS: The location of an intravitreal injection was found to have a substantial effect on elimination and distribution in the vitreous. Peak concentrations at different vitreous locations varied by over three orders of magnitude, depending on the injection location. The mean concentration of drug remaining in the vitreous 24 hours after the intravitreal injection varied by up to a factor of 3.8, depending on the injection location. Changing the volume of the injection from 15 microL to 100 microL dampened the effects of the initial injection location; however, meant concentrations at 24 hours still varied by up to a factor of 2.5. CONCLUSIONS: Careful control of the conditions of an intravitreal injection could reduce treatment variability, improve bioavailability, and reduce the possibility of retinal toxicity.

Computer Simulation↗

Risk factors for the transition from noninjection to injection drug use and accompanying AIDS risk behavior in a cohort of drug users.

Although injection drug users have been shown to reduce high-risk injection behaviors in response to the epidemic of human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS), the total elimination of risk behaviors has not been achieved. A more fundamental preventive measure may be to keep drug users from starting to inject at all. The authors selected 184 drug users from a cohort study in Amsterdam, the Netherlands, from 1985 to 1992, who had reported at entry to the study that they either had never injected drugs or had injected for the last time more than 1 year before the initial visit. Over a 5-year follow-up period, impressively high cumulative rates of transition to injection drug use were found in both groups. Among drug users who had never injected drugs, 30% began injecting; among those who had injected drugs 1-5 years before their entry into the study, 70% started injecting again. These rates were stable over time. The authors also confirmed that new injectors are at high risk of acquisition of HIV infection. With the use of a survival and a nested case-control analysis, the following independent risk factors that increased the likelihood of starting to inject were found: previous injecting history, ethnicity other than Surinamese/Antillean, regular long-term use of cocaine, current use of heroin, and a current steady sexual relationship with a partner who injects drugs. Given the high and stable incidence of initiation of injection among drug users within the cohort study, the prevention of this behavior appears to be difficult. Additional studies are needed to determine effective prevention strategies.

Acquired Immunodeficiency Syndrome↗

Ordinary glass spheres as an alternative injectable material for endoscopic correction of vesicoureteral reflux.

PURPOSE: Although they are therapeutically effective, injectable materials for urinary tract are associated with various disadvantages, precluding their universal acceptance. In this study we investigated glass spheres (GSs) as an alternative injectable substance to correct vesicoureteral reflux (VUR) in an animal model. MATERIALS AND METHODS: We used 150 to 300 micro GSs suspended in agarose gel to form the injection paste. GS paste was injected into the rectus muscle and submucosa of the bladder in 8 adult New Zealand male rabbits. As a control group, vehicle only was injected into 4 rabbits. The rabbits were sacrificed to harvest the bladder, pelvic lymph nodes, kidney, liver, brain, spleen and lung at month 1 and year 1 of injection. A VUR model was then created by unroofing the 2 ureteral orifices of 12 adult sheep. GS paste was injected into the right subureter and vehicle only was injected into the left subureter. Cystourethrographies were performed at month 3 and year 1 of injection. The sheep were sacrificed at cystourethrography to harvest the bladder, lymph nodes, kidney, liver, brain, spleen and lung. RESULTS: At month 3 and year 1 of injection into rabbit tissues nodule formation was stable in position and volume. Histopathological studies of local and distant organs of the rabbit did not show any granuloma formation or migration of GS. GS paste injection corrected VUR in sheep. Re-injection of GS into still refluxing left units corrected VUR. Local and distant organs harvested from sheep did not demonstrate distant migration. CONCLUSIONS: When injected into bladder submucosa and rectus muscle, GS appears to be inert, biocompatible and efficient. Similarly it is effective for correcting VUR in an animal model. We present our data on GS, encouraging further investigation to develop an alternative injectable material for endoscopic VUR correction.

Administration, Intravesical↗

The non-specific enhancement of allergy. II. Precipitation of anaphylactic in vitro response capacity and serum IgE and IgG2a antibody synthesis in primed but non-responding rats by injection of alum.

PVG rats given injections of 1 microgram ovalbumin (OA) together with 10 mg Silica gel failed to provide serosal mast cells or lung tissue with the capacity to release histamine on in vitro challenge with the antigen. However, if such animals were injected i.p. with 100 mg of alum (without any further antigen addition) 3-9 weeks after the primary antigen injection, their mast cells and lung tissue showed a clear-cut capacity to respond in vitro, when examined 1 week after the alum injection. Injection of only 15 mg alum did not induce such a response capacity. The fading of the reactivity induced by an alum injection could be prevented by a repeated injection of the adjuvant alone. Pretreatment of the rats with cyclophosphamide (33 mg/kg) 2 days before the primary antigen injection did not affect the response capacity induced by a booster injection 3 weeks later. S.c. injection of alum also precipitated response capacity in animals primed by i.p. injection of antigen and Silica gel. The anaphylactic response capacity induced by injection(s) of alum was generally accompanied by increased levels of OA-IgE and especially OA-IgG2a antibody; however, a clear-cut correlation between either serosal mast cell or lung tissue response capacity and serum OA-IgE or IgG2a antibody titer could not be demonstrated. These data show that in primed animals, which do not express allergic response capacity, such a capacity can be induced by injecting adjuvant alone, even several weeks after the primary antigen injection.

Aluminum Hydroxide↗

Effects of intracamerally or subconjunctivally injected cross-linked hyaluronic acid on the intraocular pressure and on the anterior segment of the rabbit eye.

Cross-linked hyaluronic acid (CLH), a viscoelastic substance with a high viscosity, was injected into the left anterior chamber of 5 rabbits without simultaneous withdrawal of aqueous humour. The right eyes of the same rabbits received an equal amount of sodium hyaluronate (Healon). The intraocular pressure (IOP) of the CLH injected eyes increased four-fold immediately after the injection. One week post injection the IOP had decreased to the pre-injection level where it remained until the euthanatization of the animals 32 days post injection. Biomicroscopically CLH was seen as a slightly opaque curly mass in the anterior chamber in the eyes that otherwise were quiet in four of the rabbits. In one rabbit the injected cross-linked substance reacted immediately with aqueous and turned white. The eye was quiet and showed no inflammatory signs. In all intracamerally injected eyes, slight to moderate aqueous flare was present 4 h post injection. Aqueous flare was still present 1 day post injection in 4 eyes, but was absent 4 days post injection. Histologically no apparent inflammatory reaction was present. Occasional giant cells were seen on the anterior surface of the iris in three animals. Slight accumulation of mononuclear cells was found in the iridocorneal angle of the CLH injected eyes. At histology few mononuclear cells were also found surrounding the subconjunctivally injected CLH still present in 4 additional rabbits when euthanatized 28, 42 and 49 days post injection. The contralateral eye of these 4 animals received an equal amount of sodium hyaluronate subconjunctivally. The substance had been resorbed completely. No reactive or inflammatory signs were present.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Evening versus morning injections of growth hormone (GH) in GH-deficient patients: effects on 24-hour patterns of circulating hormones and metabolites.

Since serum GH in normal subjects displays a circadian variation with a major and consistent surge after the onset of sleep we examined whether the time of GH administration in GH-deficient patients had any impact on its action. Eight GH-deficient patients all underwent 3 4-week study schedules in random order: 1) evening (2000 h) sc GH injections, 2) morning (0800 h) sc GH injections, and 3) no GH administration. At the end of each period the patients were admitted to hospital for 24-h measurements of hormones and metabolites. For comparison, 10 age- and sex-matched healthy untreated subjects were hospitalized once under identical conditions. Mean (+/- SE) GH availability, i.e. the area under the curve (AUC; micrograms per L/12 h) for 12 h after injection was significantly greater after evening injection than after morning injections [83.3 +/- 25.4 (evening) vs. 46.0 +/- 10.6 (morning); P less than 0.01]. This might be due to higher skin and sc temperatures when in bed. The 2000-0800 h AUC after evening injection was similar to the corresponding AUC in the reference group. Mean 24-h serum insulin-like growth factor-I levels (micrograms per L) were similar after evening (189.8 +/- 2) and morning (179.5 +/- 5.3) injections (P = 0.8), but the latter displayed a circadian variation suggesting that a steady state had not been reached. Both were significantly lower than the stable reference value (248.4 +/- 3.6 micrograms/L). Blood glucose profiles after morning and evening GH did not differ from that of the reference group, whereas blood glucose decreased when the patients received no GH (P less than 0.01). Daytime (0800-2400 h) insulin levels were increased after morning injections (P less than 0.05). Nighttime levels of lipid intermediates were below normal in the untreated state and after morning injection (P less than 0.05), whereas nighttime blood alanine tended to be above normal after morning GH injection (P = 0.08). Highly significant inverse relationships between circadian lipid intermediates and both blood alanine and lactate concentrations were observed in the reference group and in the patients after evening injections. These relationships disappeared after morning injections. We conclude that the metabolic effects of sc GH injections are clearly influenced by the time of administration and that the closest similarity to normal hormone and metabolite patterns and relationships is reached by GH injection in the evening in GH-deficient patients.

3-Hydroxybutyric Acid↗

Antioxidant status affects color stability and tenderness of calcium chloride-injected beef.

The objectives of this study were to determine whether vitamin E supplementation influences color and tenderness of beef injected with calcium chloride. Market heifers (n = 12) were fed a standard finishing diet with minimal levels of vitamin E (NE group). Another 12 market heifers were fed the NE diet with the inclusion of 1,000 IU/d of DL-alpha-tocopherol per animal for the last 125 d on feed (E group). Animals were slaughtered after 125 d on the diets and upon reaching an ultrasound backfat thickness > 10 mm. Half of the longissimus muscles from each treatment group (NE and E) were pumped to 10% over the original weight with 250 mM CaCl2 (Ca) at 24 h postmortem. Remaining muscles (NE and E) were pumped to 10% over the original weight with water (NC) at 24 h postmortem. After equilibrating overnight, steaks (2.54 cm) were overwrapped with O2-permeable film and stored for 7 d after injection. Hunter "L," "a," and "b" values were obtained each day of storage. Trained panelists evaluated color on d 1, 4, and 7 after injection. 2-Thiobarbituric acid-reactive substances (TBARS) values were measured on d 1 and 7 after injection. Warner-Bratzler (W-B) shear force values and trained sensory panel evaluations at 1, 3, and 7 d after injection were obtained. Immunoblotting techniques were used to monitor the 30-kDa degradation product of troponin-T at 1, 3, and 7 d after injection. At 4 d after injection, E/Ca steaks were the least discolored (P < 0.05). The E/Ca steak TBARS values were not significantly different from values for NE/NC steaks at 7 d after injection, whereas NE/Ca steaks had greater (P < 0.05) TBARS values after 7 d following injection compared with all other groups. Treatment with Ca resulted in higher off-flavor scores (P < 0.05). The E/Ca samples had the most rapid tenderization and proteolysis of all treatment groups. Warner-Bratzler shear values were lower in the E/Ca samples than in the E/NC samples at 1, 3, and 7 d after injection (P < 0.05). No difference in shear force was noted between NE/Ca and NE/NC samples at any time point. No difference in sensory tenderness was noted between NE/Ca and NE/NC samples at 1 d after injection. However, Ca-injected samples (NE/Ca and E/Ca) were rated as being significantly more tender than their uninjected counterparts (NE/NC and E/NC) at 3 and 7 d after injection. Injection of CaCl2 may result in more rapid and immediate tenderization if beef from animals supplemented with vitamin E is used. Vitamin E incorporation into muscle tissue may potentiate the action of exogenously added calcium by protecting the calpains from oxidation.

Animals↗

Testicular function after local injection of 6-hydroxydopamine or norepinephrine in the golden hamster (Mesocricetus auratus).

Although there is evidence for the sympathetic innervation of the mammalian testis, the function of noradrenergic fibers is not understood. This in vivo and in vitro study in the adult golden hamster examines testicular function after unilateral intratesticular application of a single dose of 6-hydroxydopamine (6-OHDA), a neurotoxic drug known to produce depletion of noradrenergic stores in nerve endings. The contralateral testis in each animal was injected with vehicle alone and served as the control. After 24 h, the content of norepinephrine (NE) in testicular parenchyma was reduced in most testes injected with 6-OHDA. At this time, concentration of luteinizing hormone receptors (LH-R) was significantly decreased in the 6-OHDA treated testis, compared with the vehicle-injected testes. This decrease was followed by a significant increase at 72 h. The concentration of LH-R was not significantly altered 10, 48, 144, or 168 h after 6-OHDA administration. Changes in testicular testosterone (T) concentrations paralleled the changes in LH-R at most time points. In the incubations of control vehicle injected testes, addition of NE did not affect T production but stimulatory action of hCG was significantly augmented by concomitant exposure to NE at most time points after injection of vehicle. In incubations of 6-OHDA-injected testes, a comparable pattern of T responses to NE and hCG was found only 48 h after injection. At 24 h post injection NE alone significantly stimulated T production; at 10 and 24 h the ability of NE to potentiate the action of hCG was significantly reduced, while at 72 and 144 h basal T production and the stimulatory hCG effect were significantly increased. Moreover, at 72, 144, and 168 h, the effect of NE & hCG on T production was significantly greater in 6-OHDA-injected testes than in the vehicle injected testes of the same animals. In incubations of untreated hamster testes, addition of 6-OHDA at doses similar to those used for injections did not affect T production. Weights of 6-OHDA injected testes were slightly but significantly reduced after 144 and 168 h. These changes were most likely due to degenerative changes of the germinal epithelium, which were clearly detectable 168 h post injection. Because 6-OHDA can release NE from nerve terminals, the observed effects of 6-OHDA might have been initiated by supernormal testicular NE concentrations. To examine this possibility, the authors have tested the effects of intratesticular NE injections. This treatment caused decrease of LH-R at 24 h followed by an increase at 72 h.(ABSTRACT TRUNCATED AT 400 WORDS)

Analysis of Variance↗

Comparison of subdermal and peritumoral injection techniques of lymphoscintigraphy to determine the sentinel lymph node in breast cancer.

PURPOSE: The purpose of this study was to evaluate 2 different injection techniques for lymphoscintigraphy to determine the axillary sentinel lymph node (SLN) in patients with breast cancer. METHODS: Thirty-six patients with early breast cancer were studied prospectively. Both peritumoral (PT) and subdermal (SD) injections were performed on each patient with Tc-99m rhenium sulfide colloid. PT injections were done 1 to 8 days before surgery and SD injections were done on the day of operation. An intraoperative gamma probe was used to explore the axillary SLNs prior to tumor excision and axillary dissection. All surgical specimens were evaluated histopathologically. RESULTS: In 19 of 36 patients, the same lymphatic drainage sites were observed with both techniques. Of these, 17 patients showed only axillary, 1 showed axillary and internal mammary (IM), and 1 showed axillary and subclavicular drainage sites. With PT injections 26 of 36 patients (72%), and with SD injections 33 of 36 patients (92%), showed axillary drainage and axillary SLNs. With PT injections 9 patients, and with SD injections only 2 patients, did not show any drainage site. During the operation with a gamma probe, axillary SLNs were excised in 35 patients (success rate, 97%). IM drainage was seen in 8 of 36 patients who underwent PT injections and in 3 of 36 with SD injections. CONCLUSION: The success rate was found to be higher with the SD injection technique than with PT injections to visualize the axillary SLN. To increase the visualization of both axillary and IM SLNs, it may be useful to perform lymphoscintigraphy with SD and PT injections together.

Axilla↗

A study of the disposition of procaine penicillin G in feedlot steers following intramuscular and subcutaneous injection.

The disposition of an aqueous suspension of procaine penicillin G (300,000 U/mL) was studied in feedlot steers. Four groups of three steers were used. Steers in groups 1 and 2 received procaine penicillin G once daily for 5 days intramuscularly (i.m.) at a dose of 24,000 U/kg (group 1) or of 66,000 U/kg (group 2). The injection on the last day was administered in the gluteal muscle. Steers in group 3 (i.m. neck injection) and group 4 [subcutaneous (s.c.) injection] each received a single dose of procaine penicillin G at a dose of 66,000 U/kg. From every animal, after the last injection in groups 1 and 2 and following the single injection in groups 3 and 4, a series of blood samples was taken at fixed time intervals. The plasma from these samples was analysed for penicillin G by a high performance liquid chromatography (HPLC) assay in order to determine the disposition of penicillin. The maximum plasma concentration (Cmax) and the area under the curve (AUC) were significantly different between groups 1 and 2, but we found no difference in the disappearance rate constant between these two groups. Group 4 single s.c. injections produced a lower mean Cmax (1.85 +/- 0.27 microgram/mL) than the mean Cmax (4.24 +/- 1.08 micrograms/mL) produced in group 3 by i.m. injections into the neck muscle or the mean Cmax (2.63 +/- 0.27 microgram/mL) produced in group 2 by i.m. injections into the gluteal muscle. However the mean Cmax produced by i.m. injections into the neck muscles (group 3) was higher than the mean Cmax produced by i.m. injections into the gluteal muscle (group 2). Additionally, the disappearance t1/2 was longer (18.08 h) in group 4 following the s.c. injection and shorter (8.85 h) in group 3 following the i.m. neck injection, than the t1/2 following administration of the same dose i.m. into the gluteal muscle (15.96 h) in group 2. In this study, when procaine penicillin G was injected into the gluteal muscle, doses of 66,000 U/kg were necessary to produce plasma concentrations that were above a minimum inhibitory concentration (MIC) for penicillin G of 1.0 microgram/mL as compared to doses of 24,000 U/kg.

Animals↗

Subcutaneous versus intracutaneous injections of sterile water for labour analgesia: a comparison of perceived pain during administration.

OBJECTIVE: To investigate whether, during injections of sterile water, there is any difference in perceived pain between intracutaneous and subcutaneous injections. DESIGN: Blind controlled trial with cross-over design. SETTING: Göteborg and Skövde, Sweden. PARTICIPANTS: One hundred healthy female volunteers. METHODS: The women were randomised into two groups and subjected to two trials, within one week of each other. During the first trial one group (n = 50) received the intracutaneous injection first, followed by the subcutaneous injection. The second group (n = 50) was given the subcutaneous injection first, followed by intracutaneous injection. In both groups all the injections were given in reverse order during the second trial. MAIN OUTCOME MEASURES: Experienced pain during the administration of sterile water injections, measured by visual analogue scale. RESULTS: The analysis showed intracutaneous injections to be significantly more painful than subcutaneous injections, even after adjusting for injection day and for left/right site of injection (mean 60.8 vs 41.3, P < 0.001). CONCLUSIONS: The findings suggest that the less painful subcutaneous injection technique should be used.

Adolescent↗

Detection of neurovascular structures using injection pressure in blockade of brachial plexus in rat.

In the last few decades there has been a great development of regional anesthesia; all the postulates are defined and all the techniques of usage are perfected. However, like any other medical procedure, the block of brachial plexus carries a risk of certain unwanted complications, like possible intraneural and intravascular injections. The reason for great discrepancy between the injury of brachial plexus and other periphery nerves while performing the nerve blockade is the frequent usage of this block, but also the specific proximity of neurovascular structures in axilla. The purpose of this work is to determine the values of pressures which appear in para-neural, intraneural and intravascular injection applications of local anesthetic, and to compare those values in order to avoid cases of intraneural and intravascular injections in clinical practice with consequential complications. In experimental study there have been used 12 Wistar rats of both genders. After anesthesia with ether and mid-humoral access to the neurovascular structures in axilla, the injection of 2% lidocaine with epinephrine was performed with the help of automatic syringe charge. The needle was at first placed para-neural, and then also intraneural and intravascular. During every application the pressure values were monitored using the manometer, and then they were analyzed by special software program. All para-neural injections resulted with the pressure between 13,96-27,92 kPa. The majority of intraneural injections were combined with the injection pressure greater than 69,8 kPa, while the intravascular injections were combined with injection pressure less than 6,98 kPa. Based on the available data it can be noticed that so far none of the methods of prevention from unwanted complications of regional anesthesia can insure the avoidance of intraneural and intravascular injection of local anesthetic. Based on our research it is obvious that the measuring of pressure during the nerve blockade is very important in order to decrease the risk of neurological and possible systematic complications. It is also clear that a small, mobile, and financially quite available apparatus for pressure measurement can help in differentiation between para-neural, intraneural and intravascular injection. Avoiding high injection pressure prevents from lodging the needle into intraneural space, while avoiding a very low injection pressure prevents from lodging the needle into intravascular space followed by consequential complications. The usage of this apparatus can find its application in other blockades of periphery nerves, and in other branches of medicine as well.

Anesthetics, Local↗

Comparison of insulin levels after injection by jet stream and disposable insulin syringe.

Intermediate-acting biosynthetic human (NPH) insulin was administered by disposable insulin syringe into the right upper thigh of nine insulin-dependent diabetic youths. Seven days later, the same amount and type of NPH insulin was given in the same anatomic site with a Medi-Jector II, which delivers insulin as a jet stream. Blood was collected before insulin injection and at hourly intervals subsequently for the measurement of glucose and insulin. The total serum insulin measured before the first morning dose with the needle and syringe and the Medi-Jector II was 41.2 +/- 10.7 microU/ml and 46.2 +/- 10.7 microU/ml, respectively. During the next 9 h, the areas under the respective total insulin curves were not different, but the area under the free-insulin curve after jet injection was greater than the free-insulin area after needle injection (P less than .01). The ratio of free/total serum insulin was 0.31 +/- 0.02 after needle injection and 0.40 +/- 0.03 after jet injection (P less than .0025). The peak of total insulin concentration occurred 4.2 h after jet injection of NPH: 1 h earlier than the peak after needle injection. The plasma glucose at time zero was 197 +/- 15 mg/dl before needle injection and 242 +/- 19 mg/dl before jet injection. Although the diet consumed by each subject on the 2nd study day was identical to that of the 1st day, the mean glucose increase was greater after needle-injected insulin than after jet-spray injection. This indicates that the greater amount of free insulin observed after jet-injected insulin had a direct effect in lowering the plasma glucose. Jet injection may reduce insulin requirements by increasing the availability of free insulin.

Absorption↗

Optimization of a blood pool contrast agent injection protocol for MR angiography.

PURPOSE: To design an ideal first-pass profile for MR angiography (MRA) by optimizing a multiphasic injection protocol based on two experimental animal models. MATERIALS AND METHODS: An equivalent contrast-enhanced (CE) MRA injection protocol was developed with controlled injection modalities (injection rate, volume, and dose) in rabbits and pigs. P792, a blood pool contrast agent, was injected in 17 male New Zealand rabbits and five farm pigs with variable injection schemes (mono- and multiphasic). From the gadolinium (Gd) blood concentration data, a simulation of an MR acquisition was performed to evaluate the impact of such an injection protocol on MR arterial signal and to select the best injection protocol. RESULTS: An empirical relationship between the arterial peak concentration and the injection parameters was found in the rabbits and pigs, allowing precise prediction of the first-pass profile. Of the four injection scheme strategies tested (standard bolus and bi-, tri-, and multiphasic injection protocols), the multiphasic "ramp" injection protocol provided the most optimal contrast agent pharmacokinetics with a durable plateau of concentration. CONCLUSION: Ramp injection protocol provides an optimized first-pass profile for CE-MRA.

Animals↗