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PubMed1995

Blood filtration in children with severe sepsis: safe adjunctive therapy.

OBJECTIVE: To review the safety and efficacy of haemofiltration and plasmafiltration in children with severe sepsis. DESIGN: Retrospective case notes analysis. SETTING: University Paediatric Intensive Care Unit. PATIENTS: All children admitted to the intensive care unit between November 1985 and May 1992 with a primary diagnosis of severe sepsis who also received blood filtration therapy. INTERVENTIONS: Continuous haemofiltration (HF) 18 patients; continuous haemofiltration and plasmafiltration (PF) 9 patients. MEASUREMENTS AND RESULTS: 27 children with sepsis-induced MOSF, median age 26.6 months (range 0.33-185), median weight 12 kg (range 2.5-58), mean PRISM score 19.4 (SD 8.6), mean number of organs failing 2.78 (SD 0.9) received filtration for a median duration of 36 hours (range 2-145). Eight (30%) survived (HF 5/18, PF 3/9). There was no significant difference in the demographic features between the HF group and the PF group and no difference in mortality. The two groups were pooled to assess the effect of commencement of filtration on clinical wellbeing. Arterial blood gases, electrolytes, full blood examination, ventilator settings and doses of inotropes were recorded immediately prior to commencement of filtration and 18 h after commencement. Serum anion gap and osmolality were calculated using conventional formulae. There were no significant changes in the level of cardiorespiratory support, or biochemical markers of severity following commencement of filtration. Platelet count fell 32% (p = 0.029) but no bleeding was encountered. No severe complications were observed during 1222 h of filtration. No bleeding or infection was observed at the site of cannulation. One child developed haemodynamic instability following commencement of plasmafiltration necessitating abandonment of the procedure. CONCLUSION: Haemofiltration or plasmafiltration can be performed safely in children with severe sepsis but their effect on outcome remains unknown.

Adolescent↗
PubMed1993

Effects of orthostatic stress on peripheral capillary filtration in mild congestive heart failure after healing of myocardial infarction.

Patients with heart failure have impaired baroreflex control of the peripheral circulation with attenuated vasoconstrictor response during orthostatic stress. The aim of this study was to test if this impaired baroreflex control not only affects the arterial, but also the capillary bed. Blood flow and capillary filtration were measured in the forearm (plethysmography) in 7 normal subjects and 7 patients with mild congestive heart failure (New York Heart Association functional class II). Measurements were done with the subjects supine and during head-up tilt at 45 degrees. While supine, forearm vascular resistance and capillary filtration coefficient did not differ significantly between the groups. In the control subjects, tilt decreased capillary filtration coefficient by 14 +/- 3% (p < 0.02), and increased forearm vascular resistance by 88 +/- 37% (p < 0.02); in contrast, patients with heart failure had an increase in capillary filtration coefficient of 26 +/- 5% (p < 0.02) and only increased the forearm vascular resistance by 10 +/- 1%, (p = NS, p = 0.26). Our data provide evidence that patients with mild heart failure, in contrast to normal subjects, increase the peripheral capillary filtration during orthostatic stress. The data indicate that impaired baroreflex mechanisms might influence the capillary filtration and it is suggested that impaired baroreflex control of the peripheral circulation can contribute to formation of edema in patients with heart failure.

Adult↗
PubMed1980

Effects of lipid-soluble substances on the thermotropic properties of liposome filtration.

Filtration of dimyristoyl phosphatidylcholine or dipalmitoyl phosphatidylcholine liposomes at various temperatures from 3 to 60 degrees C revealed a discontinuous change in filtration behavior centered about the gel-to-liquid crystal transition temperature. This change was continuous at temperatures immediately above or below the transition temperature. Although pure dipalmitoyl phosphatidylcholine liposomes are in the gel state at 22 degrees C, passage of liposomes composed of dipalmitoyl phosphatidylcholine and cholesterol through the filters at 22 degrees C gave results similar to those obtained with liquid-crystal liposomes. Low cholesterol concentrations were nearly as effective as high concentrations in producing this behavior; this observation is consistent with a shear mechanism for reduction of liposome size, since the stress induced by passage of the otherwise rigid liposome through a small pore would be relieved by fracture at a lattice imperfection. Liposomes composed of egg phosphatidylcholine and cholesterol were retained by the filters to a slightly greater extent than pure egg phosphatidylcholine liposomes; these results are consistent with the known condensing effect of cholesterol on liquid-crystal lipsomes and a shear mechanism occurring with filtration. Liposomes composed of dipalmitoyl phosphatidylcholine and either dipalmitoyl phosphatidic acid or dicetyl phosphate were filtered at 22 degrees C; they showed a filtration characteristic similar to liquid-crystal liposomes. Inclusion of the water-soluble dyes eosin Y or Evans blue in dipalmitoyl phosphatidylcholine liposomes resulted in filtration at 22 degrees C which was similar to that observed for liquid-crystal liposomes. The dyes, sodium fluorescein, 6-carboxyfluorescein and fluoresceinisothiocyanate dextran, did not alter 22 degrees C liposome filtration.

Cholesterol↗
PubMed1995

Excimer laser filtration surgery.

PURPOSE: In order to remove precisely scleral tissue overlying Schlemm's canal with minimal trauma as an outpatient procedure under local anesthetic, we used a VisX Twenty/Twenty excimer laser. METHODS: We performed excimer laser filtration in three enucleated pig eyes, seven enucleated human eyes, and seven eyes of seven patients with severe glaucoma. Precise ablation to Schlemm's canal was confirmed by scanning electron microscopy in the enucleated eyes. For the patients, a local anesthetic was used, and a custom-made holder was used to mobilize the conjunctiva and fix the eye. RESULTS: A functional sclerostomy was obtained with 1,780 to 5,965 pulses, using a 2 x 1-mm slit. In our mean follow-up of nine months (range, six to 12 months) the excimer laser filtration technique achieved controlled filtration in five of seven patients and minimized conjunctival trauma. One patient subsequently underwent cataract extraction. CONCLUSIONS: This study indicates that excimer laser filtration is an effective technique for achieving filtration in glaucoma. It may reduce the complications of glaucoma filtration surgery, particularly the incidence of shallow anterior chamber postoperatively, as it leaves the trabecular meshwork intact.

Aged↗
PubMed2003

Receiver operating characteristic analysis: a general tool for DNA array data filtration and performance estimation.

A critical step for DNA array analysis is data filtration, which can reduce thousands of detected signals to limited sets of genes. Commonly accepted rules for such filtration are still absent. We present a rational approach, based on thresholding of intensities with cutoff levels that are estimated by receiver operating characteristic (ROC) analysis. The technique compares test results with known distributions of positive and negative signals. We apply the method to Atlas cDNA arrays, GeneFilters, and Affymetrix GeneChip. ROC analysis demonstrates similarities in the distribution of false and true positive data for these different systems. We illustrate the estimation of an optimal cutoff level for intensity-based filtration, providing the highest ratio of true to false signals. For GeneChip arrays, we derived filtration thresholds consistent with the reported data based on replicate hybridizations. Intensity-based filtration optimized with ROC combined with other types of filtration (for example, based on significances of differences and/or ratios), should improve DNA array analysis. ROC methodology is also demonstrated for comparison of the performance of different types of arrays, imagers, and analysis software.

Data Interpretation, Statistical↗
PubMedDate not supplied

Clarification of yeast cell suspensions by depth filtration.

Depth filtration can be very attractive for initial clarification because of low capital costs and ease of operation. However, there is currently no fundamental understanding of the effects of the filter pore size and morphology on the overall capacity and filtrate quality. The objective of this study was to examine the flux, capacity, and filtrate turbidity of a series of depth filters with different pore size ratings and multilayer structures for the filtration of yeast cell suspensions. Data were analyzed using available fouling models to obtain insights into the flux decline mechanisms. Filters with small pore size provide high filtrate quality at low capacity, with the reverse being true for the larger pore sizes. The multilayer structure of commercial depth filters leads to improved performance, although the choice of layer properties is critical. The highest capacity was achieved using a multilayer filter in which the upper layer allows significant yeast cell penetration into the filter matrix but still protects the retentive layer that is needed for a high quality filtrate.

Cell Culture Techniques↗
PubMed2003

Air filtration units in homes with cats: can they reduce personal exposure to cat allergen?

BACKGROUND: Domestic air filtration units have previously been shown to cause a dramatic fall in airborne pet allergen levels in homes with pets. Clinical trials of air filtration units, however, have failed to reveal a significant beneficial effect. Personal pet allergen exposure during air filtration unit use has never been measured. OBJECTIVE: To determine the effect of air filtration on inhaled cat allergen exposure in homes with cats. METHODS: Nasal air samplers were worn to measure personal cat allergen exposure. The study was carried out in five homes with cats on 4 separate days examining four experimental conditions (cat absent or present, air filtration off or on). The two operators collected four baseline samples and two 15-min samples/h over three consecutive hours. Cat allergen-bearing particles were detected by immunoblotting and allergen concentrations measured by amplified enzyme-linked immunosorbent assay (ELISA). RESULTS: There was a significant reduction in the quantity of the inhaled Fel d 1 when the air cleaner was used with the cat in the room. Fel d 1 halo counts (detransformed means) were 29.3 at baseline, 11.8 after 1 h, 10.0 after 2 h and 14.1 after 3 h, with no change on control days (P = 1.00). With the cat elsewhere in the house, a marginal, but statistically significant reduction was observed only after 3 h with the use of air cleaner (Fel d 1 halo count: baseline 12.4; 3 h 5.5; P = 0.01). CONCLUSIONS: The use of air filtration units appears to result in a much smaller reduction of inhaled cat allergen exposure than suggested by previous studies using standard air samplers. Cat removal remains the best advice to cat-allergic patients who experience symptoms upon exposure.

Air Conditioning↗
PubMed1989

Homozygous familial hypercholesterolemia. Selective removal of low-density lipoproteins by secondary membrane filtration.

Selective plasma filtration with a hollow-fiber membrane device was compared prospectively to plasma exchange in the therapy of a patient with homozygous familial hypercholesterolemia. Four liters of patient plasma was removed biweekly during each of six consecutive plasma exchanges, after which 20 consecutive biweekly 4-liter filtration procedures were conducted. The hollow-fiber membrane retained 94 percent of the low-density lipoprotein (LDL) cholesterol presented to it, and allowed passage of 83 percent of the albumin, 68 percent of the IgG, and 47 percent of the high-density lipoprotein (HDL) cholesterol. Both plasma exchange and plasma filtration decreased the patient's total and LDL cholesterol levels by 80 percent. However, filtration removed significantly less HDL than did exchange (54 versus 71% reduction in HDL levels, respectively); preserved significantly higher levels of IgG, clotting factors, and complement components; and avoided the need for expensive albumin replacement solutions. In addition, the patient tolerated the filtration procedures significantly better than the exchanges. Newer apheresis techniques that selectively deplete plasma of LDL cholesterol, such as secondary membrane filtration, are likely to replace plasma exchange as the therapy of choice in patients with homozygous hypercholesterolemia.

Blood Coagulation Factors↗
PubMed2001

Influence of temperature, filter wettability, and timing of filtration on the removal of WBCs from RBC concentrates.

BACKGROUND: The efficacy of the removal of WBCs from buffy coat-reduced RBC concentrates by filtration is determined by many variables. The aim of this study was to investigate the influence of the filtration temperature, the wettability of the filter material, and the timing of the filtration after collection. STUDY DESIGN AND METHODS: The investigation used commercially available filters: 3 dry "online" filters (Cellselect FR, Fresenius Hemocare; BioR-01-max, Fresenius; Leucoflex LCG1, MacoPharma) and one wet "inline" filter (Leucoflex LCR4, MacoPharma) that contained saline-adenine-glucose-mannitol additive solution for RBCs and differed from the online version only in wettability. After buffy coat removal and suspension in saline-adenine-glucose-mannitol, filtrations were performed immediately at room temperature (RT) and after 2 hours' storage of the RBC concentrates at 4 degrees C, while the Leucoflex LCR4 was also tested after 24 hours' storage of the RBC concentrates at 4 degrees C. Sets of 12 pooled experiments were performed to prevent donor-dependent differences. RESULTS: The Cellselect FR gave significantly better WBC removal from RBC concentrates at 4 degrees C than at RT, with residual WBCs of 1.44 +/- 0.58 x 10(6) and 2.78 +/- 1.23 x 10(6), respectively (p<0.001). The BioR-01-max gave no significant difference: 0.62 +/- 0.27 x 10(6) WBCs (at 4 degrees C) versus 0.61 +/- 0.25 x 10(6) WBCs (at RT). Filtration with the Leucoflex LCG1 resulted in 0.06 +/- 0.03 x 10(6) and 0.07 +/- 0.07 x 10(6) WBCs at 4 degrees C and RT, respectively, which is not a significant difference. The Leucoflex LCR4, however, gave 2.08 +/- 0.84 x 10(6) WBCs at RT, 0.52 +/- 0.44 x 10(6) WBCs at 4 degrees C after 2 hours' cooling, and 0.05 +/- 0.10 x 10(6) WBCs at 4 degrees C after 24 hours' cooling (all p<0.001). CONCLUSION: Temperature, filter wettability, and timing of filtration after collection influence the efficacy of a filter for RBC concentrates. These variables need to be established, validated, and controlled before a filter can be selected for routine use.

Blood Component Removal↗
PubMed1956

Studies on the transfer of lymph node cells. VII. Transfer of cells incubated in vitro with filtrates of trypsin-treated suspensions of Shigella paradysenteriae.

Shigella paradysenteriae organisms were incubated in a solution of trypsin and then removed from the suspension by Seitz filtration. Serologic tests with anti whole Shigella serum indicated that the filtrate contained antigenic material derived from the organisms. When lymph node cells from rabbits not previously injected with Shigella were incubated in vitro with such filtrates and then transferred to irradiated recipients, agglutinins to Shigella appeared in the sera of the latter. The transfer of heated suspensions of cells was not followed by the appearance of agglutinins in irradiated recipient rabbits. Non-irradiated recipients of lymph node cells incubated with the filtrate also developed agglutinin titers, to a lower level than irradiated animals. Agglutinins did not appear in the sera of the majority of non-irradiated recipients of heated cells. The addition of excess antiserum to either the filtrate or the cell suspension before the incubation of these two materials resulted in a marked reduction in the subsequent agglutinin titers of recipient animals. However, if antiserum was added at the conclusion of the usual 30 minute incubation of cells and filtrate, or even after 5 minutes of incubation, there was no reduction in the agglutinin titers of the recipients. Cytologic examination of aliquots of a number of the suspensions of cells prepared for transfer revealed that approximately 98 to 99 per cent of the cells belonged to the lymphocytic series.

Animals↗
PubMed2006

The influence of high-efficiency particulate air filtration on mortality and fungal infection among highly immunosuppressed patients: a systematic review.

BACKGROUND: Patients with hematological malignancies who are treated with intensive chemotherapy or who receive bone marrow transplants are exposed to an increased risk of developing nosocomial fungal infections. The aim of this systematic review was to compare the effectiveness of high-efficiency particulate air (HEPA) filtration with that of non-HEPA filtration in decreasing the rates of mortality and fungal infection among patients with diagnosed hematological malignancies and neutropenia or among patients with bone marrow transplants. METHODS: Articles identified in a Medline search, guidelines, and books, as well as the bibliographies of review articles, monographs, and the articles identified by Medline, were researched. Randomized trials and observational studies comparing HEPA filtration with conventional room ventilation were selected for inclusion in the present review. RESULTS: Sixteen trials (9 with death as an outcome and 10 with fungal infection as an outcome) that compared HEPA filtration with non-HEPA filtration were selected for meta-analyses. We discovered no significant advantages of HEPA filtration in the prevention of death among patients with hematological malignancies with severe neutropenia in randomized controlled trials (RCTs; relative risk [RR], 0.86 [95% confidence interval {CI}, 0.65-1.14]) and in studies of a lower standard (non-RCTs; RR, 0.87 [95% CI, 0.60-1.25]). CONCLUSIONS: The placement in protected areas of patients with hematological malignancies with severe neutropenia or patients with bone marrow transplants appears to be beneficial, but no definitive conclusion could be drawn from the data available.

Air Microbiology↗
PubMed1998

Limb capillary filtration coefficient in human subjects: the importance of the site of measurement.

Capillary filtration coefficient is a critical determinant of fluid flux across the microvascular wall. Changes in capillary filtration coefficient have been described in a number of disease processes. Measurement is typically made by venous occlusion plethysmography using either the upper or lower limb, but a variety of measurement protocols have been used and the importance of the site of measurement remains unclear. In this study, forearm and calf capillary filtration coefficient were measured in healthy volunteers, either simultaneously (group A; n = 11) or sequentially in random order (group B; n = 11) using venous occlusion plethysmography, with the subject supine and the limb at heart level. In both studies capillary filtration coefficient was significantly higher when measured at the forearm than at the calf (group A: 6.1 +/- 1.0 versus 3.7 +/- 1.1 x 10(-3) ml min(-1) mmHg(-1) 100 ml(-1) (mean +/- SD), p < 0.01; group B: 5.1 +/- 1.2 versus 3.2 +/- 1.1 x 10(-3) ml min(-1) mmHg(-1) 100 ml(-1), p < 0.01). Isovolumetric venous pressure (the maximum pressure at which there is neither net filtration nor absorption at the microvascular wall) was similar in upper and lower limbs in both groups of subjects. We conclude that limb capillary filtration coefficient is dependent on the site of measurement. Caution is required when comparing data recorded at different sites even if corrected for the volume of soft tissue under study.

Adult↗
PubMed1999

Accumulation of advanced glycation end products in the peritoneal vasculature of continuous ambulatory peritoneal dialysis patients with low ultra-filtration.

BACKGROUND: Ultra-filtration failure is a serious complication of long-term continuous ambulatory peritoneal dialysis (CAPD). This complication is related to histological changes of the peritoneum, i.e. severe interstitial fibrosis and microvascular sclerosis. Although their pathogenesis has not been elucidated yet, advanced glycation end products (AGEs) have been shown to accumulate in the peritoneal tissue of CAPD patients. METHODS: Peritoneal biopsy specimens from 14 CAPD patients with low ultra-filtration (n = 9) and high ultra-filtration (n = 5) capacity were immunohistochemically investigated using a monoclonal antibody against AGEs (6D12). The severity of peritoneal fibrosis, microvascular sclerosis and intensity of AGE accumulation were semi-quantitatively evaluated. Peritoneal ultra-filtration capacity was evaluated by calculating daily ultrafiltration volume per body weight (UFV/BW) and D/D0 (glucose) of the peritoneal equilibration test. RESULTS: In all patients with low ultra-filtration, AGE accumulated in the peritoneal fibrous tissue and microvascular walls. Remarkably, AGE accumulated more intensely in hyalinized fibrosis of small venular media. Extent of AGE accumulation in peritoneal interstitium and vascular walls correlated with the progression of interstitial fibrosis (rho = 0.727, P = 0.0088) and vascular sclerosis (rho = 0.915, P = 0.001). UFV/BW was inversely correlated to interstitial fibrosis (rho = -0.660, P = 0.0174), microvascular sclerosis (rho = -0.671, P = 0.0155) and microvascular AGE accumulation (rho = -0.678, P = 0.0145). CONCLUSIONS: In CAPD patients, AGE formation in the peritoneum correlates with the development of severe interstitial fibrosis and microvascular sclerosis, which is associated clinically with impaired peritoneal ultra-filtration.

Adult↗
PubMed1998

Different effects of calcium antagonists on fluid filtration of large arteries and albumin permeability in spontaneously hypertensive rats.

OBJECTIVE: To compare the effects of chronic administration of two dihydropyridines, nifedipine and amlodipine, and the non-dihydropyridine Ca2+ antagonist mibefradil on fluid filtration of large arteries and extravasation of albumin in spontaneously hypertensive rats. METHODS: Spontaneously hypertensive rats aged 2 months were randomly allocated to oral treatment once a day with 30 mg/kg mibefradil (n=12), 100 mg/kg nifedipine (n=12), 20 mg/kg amlodipine (n=12) or placebo (n=12) for 1 month. Instantaneous blood pressure of rats under pentobarbital anaesthesia was recorded at the end of the treatment Fluid filtration across the carotid arterial wall was determined in situ in the isolated carotid artery. Extravasation of 25 mg/kg Evans Blue dye that had been injected intravenously was used to assess whole vascular permeability to albumin after chronic treatment with mibefradil. RESULTS: Similar reductions in mean arterial pressure were obtained in all Ca2+ antagonist-treated rats. Heart rate was similar in rats in control, nifedipine and amlodipine groups but was significantly lower in mibefradil-treated rats (by 19%, P< 0.001). Fluid filtration across the carotid wall was greater in all Ca2+ antagonist-treated animals. However, fluid filtration was significantly less in mibefradil-treated rats than it was in nifedipine-treated, and amlodipine-treated rats. Furthermore, administration of mibefradil did not significantly modify extravasation of albumin in all tested tissues (pancreas, testis, spleen, lung, kidney, intestine, liver, skeletal muscle) except for cardiac and brain tissues, in which the permeability of albumin was increased by 24 and 33%, respectively, compared with values for the control group (P < 0.05). CONCLUSION: These results indicate that Ca2+ antagonists increase fluid filtration through large arteries from spontaneously hypertensive rats. That the lower fluid filtration in mibefradil-treated rats was associated with no change in extravasation of albumin in most tissues and especially in skeletal muscle suggests that vascular permeability in hypertensive rats was impaired less by mibefradil treatment than it was by dihydropyridine Ca2+ antagonist treatments.

Amlodipine↗
PubMed2000

Changes in anterior chamber depth and angle width after filtration surgery: a quantitative study using ultrasound biomicroscopy.

PURPOSE: To evaluate the anterior chamber configuration by means of ultrasound biomicroscopy in patients with glaucoma and control subjects, and to determine quantitative changes in this configuration after glaucoma filtration surgery (trabeculectomy) and combined cataract and filtration surgery. METHODS: The study included 33 eyes of 33 patients with glaucoma (diagnosed with primary open-angle or exfoliative glaucoma) in which filtration surgery (n = 17) or combined cataract and filtration surgery (n = 16) was performed, and 25 eyes of 25 age-matched control subjects. Ultrasound biomicroscopy was used to measure anterior chamber depth and the angle width at 500 microm from the scleral spur in all eyes. The patients with glaucoma were examined 2 days before surgery and 3 and 6 months after surgery. RESULTS: There were no significant differences in anterior chamber depth and angle width between patients with glaucoma before surgery and control subjects. Postoperative values for anterior chamber depth were significantly greater in patients with glaucoma who underwent combined surgery, but no significant changes were observed in those who underwent filtration surgery alone. In contrast, angle width was significantly greater after surgery both in patients who underwent combined surgery and in those who underwent filtration surgery alone. CONCLUSION: On ultrasound biomicroscopic evaluation, there were no differences in anterior chamber depth and angle width between patients with glaucoma and control subjects. Trabeculectomy alone widens the angle but does not affect the anterior chamber depth; however, combined surgery both deepens the anterior chamber depth and widens the angle.

Aged↗
PubMed2004

Amino acid clearance during acute metabolic decompensation in maple syrup urine disease treated with continuous venovenous hemodialysis with filtration.

OBJECTIVE: Assessment of amino acid clearances by continuous venovenous hemodialysis with filtration in treatment of a metabolic decompensation in acute maple syrup urine disease. DESIGN: Single patient assessment. SETTING: Pediatric intensive care unit. PATIENTS: A 10-yr-old male with known maple syrup urine disease (branched chain alpha-ketoacid dehydrogenase deficiency) with metabolic decompensation due to an acute viral illness, characterized by altered mental status, progressive obtundation, and severe acidosis. INTERVENTIONS: Continuous venovenous hemodialysis with filtration. MEASUREMENTS AND MAIN RESULTS: Continuous venovenous hemodialysis with filtration was instituted with both filtration (500 mL/m(2)/hr) and dialysis (1000 mL/m(2)/hr) utilized, allowing rapid correction of systemic ketoacidosis while providing amino acid clearance. Amino acid clearance was measured at initiation and at 24 hrs into therapy. The procedure was well tolerated, with near normal mental status within 12 hrs and resumption of enteral feedings. During the 24-hr period of continuous venovenous hemodialysis with filtration, serum leucine levels fell from 2352 to 381 micromoles/L, isoleucine fell from 626 to 164, and valine fell from 1117 to 228. Leucine, isoleucine, and valine clearance rates averaged 13.1, 12.8, and 13.2 mL/min, respectively, and were constant during the 24 hrs of treatment. Clearance of other amino acids during this period did not vary significantly between cationic, anionic, neutral, or hydrophobic amino acids. CONCLUSIONS: Continuous venovenous hemodialysis with filtration provides an effective therapeutic alternative to intermittent hemodialysis during acute metabolic decompensation in maple syrup urine disease.

Acute Disease↗
PubMed1983

Measurement of water filtration in skeletal muscle in man by an osmotic transient method.

Water filtration in the human forearm was determined with a new method using a hyperoncotic transient of albumin solution infused into the brachial artery. Baseline dilution of labelled albumin in deep forearm vein plasma in excess of the contribution from arterial blood and from infusate was assumed to originate from extravascular water filtered into the blood by the transient. The filtration coefficient (Fc) was determined as the ratio between filtered water and increase in colloid osmotic pressure in the blood samples, and gives the filtrative water permeability in the exchange areas of the microcirculation. In 10 normal volunteers, Fc was 0.00082 ml (ml mmHg)-1 (SD=0.00007). Multiplication of Fc by plasma flow in the forearm gave a filtration capacity (Kf) of 0.0036 ml (100 ml tissue min mmHg)-1 (SD=0.00137). This filtration capacity (Kf) represents that of fast flowing regions in the forearm muscles, but it is of the same order of magnitude as the capillary filtration coefficient (CFC) determined plethysmographically for the entire forearm by the venous stasis technique.

Adult↗
PubMed1990

Evaluation of cytotoxic activity in fecal filtrates from patients with Campylobacter jejuni or Campylobacter coli enteritis.

We sought to determine the prevalence of cytotoxic activity in fecal filtrates from persons with C. jejuni or C. coli enteritis. Stool specimens were collected from 20 persons with C. jejuni or C. coli enteritis, 20 persons with acute diarrheal illnesses of other causes, and 9 healthy, asymptomatic persons. Fecal filtrates were then incubated with Chinese hamster ovary (CHO) or HeLa cells. The fecal filtrate from 1 of the 20 (5%) persons with Campylobacter enteritis was cytotoxic for HeLa cells at a titer of 1:40, and 10 (50%) were cytotoxic for CHO cells at maximum titers of 1:20. Cytotoxic activity for CHO cells at a median titer of 1:20 was also present in 40% of the fecal filtrates from persons with diarrhea due to causes other than Campylobacter enteritis, and in 33% of filtrates from healthy, asymptomatic persons. The observed low level of cytotoxicity in fecal filtrates from all patient groups studied likely resulted from non-specific factors, unrelated to the pathogenesis of Campylobacter enteritis.

Acute Disease↗