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Biomedical subjects

A Weber

Publications and source records attributed to A Weber.

At least 379 records · Page 21Linked to original sources

[Perioperative ultrasound examination of the breast in breast cancer].

127 cases of breast carcinoma were examined in a prospective study. By means of preoperative ultrasonography the staging following the pTNM-system validates the tumor size in 85.5% and the lymph node involvement in 77.2%. Multicentric-multifocal carcinomas were diagnosed by ultrasonography in 20 of 29 cases, merely 9 of 29 by mammography. Ultrasonography of specimen is recommended in cases of negative clinical findings and positive ultrasound examination to verify tumour excision. In addition to clinical exploration and mammography the ultrasonography of the breast obtains a diagnostic significance for planning a conservative management of breast cancer.

Breast Neoplasms↗

[The detection of the pathogenicity of Listeria using permanent cell lines as an alternative for animal studies].

Culture filtrates of 38 strains of Listeria (L.) monocytogenes and of 4 strains of L. ivanovii were all cytotoxic for the vero cell line. Culture filtrates from 35 strains of L. innocua, 12 strains of L. seeligeri, 5 strains of L. welshimeri and 4 strains of L. grayi showed no cytotoxicity for the continuous cell line vero. The use of continuous cell lines permits to distinguish between pathogenic and non-pathogenic Listeria strains and seems to be a suitable method to replace the mouse pathogenicity test or the fertilized hen's eggs test.

Animal Testing Alternatives↗

Dicloxacillin absorption and elimination in children.

We determined the apparent bioavailability of dicloxacillin in 26 children between the ages of 0.24 and 143 months by comparing the area under the serum concentration versus time curve following intravenous and oral administration of 25 mg/kg. With intravenous infusion the overall mean half-life of elimination was 0.53 +/- 0.20 h, the AUC was 70.15 +/- 32.18 mg.min/l and the apparent volume of distribution was 0.29 +/- 0.09 l/kg. The overall average bioavailability was 59.89%. Children less than 6 months old had a shorter time to peak concentration (1.39 +/- 0.49 h) and the lowest oral bioavailability (64.35 +/- 13.62%) in comparison to children more than 60 months old. In children older than 60 months the time to peak was 1.79 +/- 1.16 h and the average oral bioavailability was 79.38 +/- 32.87%. However, children less than 6 months old had the least variability in absorption, the coefficient of variation (CV) of oral bioavailability was 13.62%, while in children between 6 and 40 months old the CV was 60.4%: children older than 60 months had the most variability in absorption, a CV of 32.87%. This variability was not dependent on the formulation administered. After 5 years of age the bioavailability increased with increasing age.

Administration, Oral↗

Liver transplantation for hereditary tyrosinemia: the Quebec experience.

Sixteen tyrosinemic patients were evaluated in our institution for a possible liver transplantation. All patients showed biochemical and/or radiological evidence of liver dysfunction. Renal involvement was found to be more abnormal than expected. Seven patients have been transplanted, with two patients receiving a combined liver-kidney transplant. Hepatocarcinoma was detected in two of eight patients in whom the whole liver was examined. Six (37.5%) of the initial 16 patients have died since evaluation, one of the six dying after combined liver-kidney transplantation. Posttransplantation survival was 86%, with normal liver function, normal growth, and no recurrence of neurological crises on a normal diet.

Adolescent↗

Tropomyosin stabilizes the pointed end of actin filaments by slowing depolymerization.

Tropomyosin is postulated to confer stability to actin filaments in nonmuscle cells. We have found that a nonmuscle tropomyosin isolated from the intestinal epithelium can directly stabilize actin filaments by slowing depolymerization from the pointed, or slow-growing, filament end. Kinetics of elongation and depolymerization from the pointed end were measured in fluorescence assays using pyrenylactin filaments capped at the barbed end by villin. The initial pointed end depolymerization rate in the presence of tropomyosin averaged 56% of the control rate. Elongation from the pointed filament end in the presence of tropomyosin occurred at a lower free G-actin concentration, although the on rate constant, kappa p+, was not greatly affected. Furthermore, in the presence of tropomyosin, the free G-actin concentration was lower at steady state. Therefore, nonmuscle tropomyosin stabilizes the pointed filament end by lowering the off rate constant, kappa p-.

Actin Cytoskeleton↗

[The usefulness of three rapid commercially-available tests for the identification of Staphylococcus aureus strains isolated from animals].

3 commercially available tests STAPHYSLIDE (api bio Mérieux), STAPHYLASE (Oxoid) and STAPHAUREX-D (Welcome) for identification of Staphylococcus aureus were evaluated by 110 coagulase-positive S. aureus strains and 40 coagulase-negative Staphylococcus strains, isolated from various materials of different animal species. STAPHYSLIDE showed a sensitivity of 53.6% and a specificity of 97.5%, STAPHAUREX-D 56.4% respectively 85% and STAPHYLASE 32.7% respectively 100%. The possible reasons for the weak results of these 3 tests well established in bacteriology of human medicine by use in veterinary bacteriology are discussed.

Animals↗

Transfection of hepatic genes into adult rat hepatocytes in primary culture and their tissue-specific expression.

We describe in this paper a method for studying transient gene expression in a primary culture of adult rat hepatocytes. After isolation by collagenase perfusion, hepatocytes in a monolayer were transfected with foreign DNA by the calcium phosphate precipitation technique during the first 24 hours after plating. When they were transfected with a plasmid containing the gene for chloramphenicol acetyltransferase driven by the early promoter of simian virus 40, hepatocytes reproducibly expressed high levels of chloramphenicol acetyltransferase (CAT); this transient expression was much higher than that obtained with the rat hepatoma cell line H4II. Different medium conditions have been tested; an optimal level of CAT activity can be obtained using a serum-free, hormonally defined medium. Using these techniques, we have investigated the expression of liver-specific genes transferred into hepatocytes. We show that the L-pyruvate kinase promoter is active in these hepatocytes while it is silent in fibroblasts. Moreover, the use of serum-free medium may allow investigation of the role of hormones and nutrients in cells which respond normally to these effectors.

Animals↗

[The rapid identification of E. coli by the detection of 3 enzymes].

232 isolates of gram-negative, oxidase-negative bacteria, isolated from various samples of different animal species, were tested with help of RAPIDEC coli for the production of beta-glucuronidase, beta-galactosidase and indole. The test correctly identified 164 of 175 E. coli strains (sensitivity 93.7%) and correctly indicated that 57 of 57 isolates of the family Enterobacteriaceae (7 Citrobacter sp., 18 Enterobacter sp., 16 Klebsiella sp., 10 Proteus sp., 2 Providencia sp. and 4 Salmonella sp.) were not E. coli (specificity 100%).

Animals↗

[The occurrence of Treponema in fecal samples from dogs and cats with and without intestinal diseases].

6 (6.9%) of 87 examined dogs without diarrhoea proved to be carriers of Treponema (1x T. hyodysenteriae, 5x T. innocens), whereas in fecal samples from 62 dogs with enteric symptoms no isolation of Treponema succeeded. 5 fecal samples (3.7%) of cats without signs of diarrhoea were found to contain Treponema (1x T. hyodysenteriae, 4x T. innocens), whereas the fecal samples of 31 cats with diarrhoea didn't show any growth of Treponema by cultural investigations. Due to the results of these investigations the conclusion can be drawn that Treponema belong to the usual bacteria of dogs' and cats' intestines and cannot be suspected to cause diarrhoea in these animals primarily.

Animals↗

[The rapid identification of Escherichia coli using Bactident E. coli].

165 (93.7%) of 175 E. coli strains isolated from various materials of different animal species were correctly identified as E. coli with help of commercially available Bactident E. coli (E. Merck, D-6100 Darmstadt). Further 52 strains of the family of Enterobacteriaceae (2x Providencia sp., 2x Salmonella sp., 7 Citrobacter sp., 9 Proteus sp., 15 Klebsiella sp., 17 Enterobacter sp.) were correctly not identified as E. coli by this test. Bactident E. coli is a suitable test for rapid identification of E. coli in veterinary bacteriology.

Animals↗

Safety of aerosol tobramycin administration for 3 months to patients with cystic fibrosis.

To determine the potential toxicity of prolonged aerosol tobramycin administration, 22 patients with cystic fibrosis were monitored while receiving inhaled tobramycin three times a day for 12 weeks. Prior to, four times during administration and approximately 6 weeks after discontinuation of treatment, we assessed pulmonary function, weight, height, body temperature, eighth cranial nerve function, serum creatinine, blood urea nitrogen, urinary creatinine clearance, plasma iothalamate clearance, urinary beta-2 microglobulin concentration, and Pseudomonas aeruginosa density in sputum. There was no detectable laboratory evidence of nephrotoxicity. Neither a decrease in auditory acuity (range 250-20,000 Hz) nor vestibular dysfunction was detected. Pulmonary function tests significantly improved during the first month in all subjects (P less than 0.05) but returned to enrollment values by the end of the 12th week of administration of tobramycin aerosol. Sputum P. aeruginosa density initially decreased from a mean of 10(7) cfu/gm to a mean of 10(4) cfu/gm after 2 weeks of aerosol tobramycin administration and remained significantly below the enrollment value throughout. Coincident with the reduced bacterial density, a reduction in cough frequency and sputum production, as well as a weight gain was observed. Seventy-three percent of the patients with sputum P. aeruginosa isolates susceptible to tobramycin on enrollment yielded resistant organisms during aerosol administration. However, 1 year later all sputum P. aeruginosa isolates obtained from patients were susceptible to tobramycin. We conclude that thrice daily aerosol tobramycin administration for 3 months is not associated with detectable eighth cranial nerve or renal toxicity. Transient emergence of tobramycin resistant P. aeruginosa may occur.

Administration, Inhalation↗

Permeability of the non-selective channel in brown adipocytes to small cations.

The non-selective channel for monovalent cations of cultured brown adipocytes was studied concerning its permeability to alkali metal ions, NH4+, Tris+, Ca2+, and Ba2+. Experiments were done by means of the patch clamp technique using inside-out patches. With symmetrically increasing sodium concentrations the ion fluxes saturated. They are described by a dissociation constant (KNa) of 155 mmol/l and a maximum single channel conductance of 50 pS. Permeabilities were determined in relation to those for sodium yielding values of 0.80 for potassium and 1.55 for ammonium. The complete permeability sequence for ammonium and the alkali metals is: NH4+ greater than Na+ greater than Li+ greater than K+ greater than or equal to Rb+ congruent to Cs+ . Ca2+ and Ba2+ as well as the buffer ion Tris+ are not able to pass the channel measurably. It is shown that the conductance behaviour of the non-selective channel is not sufficiently described by the Goldman-Hodgkin-Katz theory. Deviations from independence are saturation with increased activity of the permeant ion and non-linear current voltage relations in symmetrical solutions. A simple two barrier model with one binding site in the center of the electric field is shown to be more appropriate.

Adipose Tissue, Brown↗

High mite-allergen exposure increases the risk of sensitization in atopic children and young adults.

Concentrations of major allergens of Dermatophagoides pteronyssinus (Dpt) and D. farinae (Df), Der p I and Der f I, were determined in 183 dust samples of mattresses of 133 atopic and 50 nonatopic children by a sandwich-type ELISA. Atopic children and young adults living in houses with high levels of Der p I and Der f I (greater than or equal to 2000 ng/gm of dust) were found to have significantly higher serum IgE levels to Dpt and Df (p less than 0.0001) compared to patients with low mite-allergen exposure. Washed leukocytes of 55 atopic children and 14 control subjects were investigated for in vitro histamine release to serial dilutions of Der p I; 86% of highly exposed (greater than or equal to 10,000 ng/gm) children demonstrated positive histamine release in response to Der p I compared to 17% in the group with very low exposure (less than 400 ng/gm). There was a positive correlation between basophil sensitivity (rs = 0.6; p less than 0.0001) and reactivity (rs = 0.54; p less than 0.0001) to Der p I and mite-allergen exposure. The relative risk for sensitization in the highly exposed group versus the group with very low exposure was sevenfold to 32-fold increased. We conclude that high concentrations of mite allergen (greater than or equal to 2000 ng/gm) increase the risk of specific sensitization in atopic children and young adults and thus may facilitate allergic airway disease.

Adolescent↗

Pediatric liver transplantation: the Montreal experience.

The introduction of cyclosporine A in 1980 greatly improved the survival of children with end-stage liver disease undergoing orthotopic liver transplantation. The average 1-year survival rate following hepatic transplantation increased from 30% in 1963 to 70% in 1980. This report summarizes the initial experience of two pediatric hospitals in Montreal--Hôpital Ste-Justine and Montreal Children's Hospital. Since December 1985, 13 orthotopic liver transplantations have been performed in 11 patients: six females and five males. The median age was 18 months (range, 13 months to 17 years) and the median weight was 10 kg (range, 8.5 to 38 kg). The indications for transplantation were biliary atresia (5 patients), tyrosinemia (2 patients), biliary hypoplasia (1 patient), Amerindian cirrhosis (1 patient), Crigler-Najjar syndrome, type I (1 patient), and fulminant non-A, non-B hepatitis with grade IV encephalopathy (1 patient). Immunosuppression was ensured by cyclosporine A, azathioprine, and steroids. The function of 11 grafts was immediate following revascularization of the grafts. One graft had delayed function due to preservation injury, and one had primary nonfunction. Surgical complications included bile peritonitis (1), ruptured aneurysm of an aortic conduit (1), and thrombosis of the hepatic artery necessitating retransplantation (2). Three of our patients died, one from postoperative cerebral edema, one of primary nonfunction of the graft, and one of ruptured aneurysm of an aortic conduit. Our overall survival rate was 72% with a follow-up of 3 to 32 months. Pediatric liver transplantation can now provide successful treatment and cure of liver diseases considered, until recently, dismal and hopeless.

Adolescent↗

Fluoronaphthyridines and quinolones as antibacterial agents. 1. Synthesis and structure-activity relationships of new 1-substituted derivatives.

A series of novel 7-piperazinyl-1-substituted-6-fluoroquinolones and naphthyridines have been prepared and their antibacterial activities evaluated. These derivatives are characterized by having alkyl, alkenyl, arylalkyl, cycloalkyl, and cycloalkenyl groups at the 1-position. As a result of this study, derivatives 7 and 26, which are substituted with tert-butyl groups at N-1, were found to possess excellent in vitro and in vivo potency, particularly against Staphylococcus aureus, comparable to that of norfloxacin or ciprofloxacin. Structure-activity relationships of N-1 substituted alkyls and cycloalkyls are also discussed.

4-Quinolones↗

Human early pregnancy factor and early pregnancy associated protein before and after therapeutic abortion in comparison with beta-hCG, estradiol, progesterone and 17-hydroxyprogesterone.

Serum activities and concentrations, respectively, of early pregnancy factor (EPF), early pregnancy associated protein (EPAP), beta-hCG, estradiol, progesterone and 17-hydroxyprogesterone were estimated in 20 healthy primigravidae within the tenth to twelfth completed gestational week before and after therapeutic abortion. EPF, beta-hCG and estradiol markedly decreased after termination of pregnancy, whereas progesterone and 17-hydroxyprogesterone concentrations moderately fell. EPAP showed no significant alterations in a 24 hours period. Because of its possible role as immunosuppressive substance and its short half-life EPF may be a promising immunobiomarker for disturbances in early pregnancy.

17-alpha-Hydroxyprogesterone↗