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Biomedical subjects

T Weber

Publications and source records attributed to T Weber.

At least 307 records · Page 17Linked to original sources
PubMed1990

Purine nucleoside phosphorylase: a new marker for free oxygen radical injury to the endothelial cell.

The effect of ischemia and reperfusion on purine nucleoside phosphorylase was studied in an isolated perfused rat liver model. This enzyme is localized primarily in the cytoplasm of the endothelial and Kupffer cells; some activity is associated with the parenchymal cells. Levels of this enzyme accurately predicted the extent of ischemia and reperfusion damage to the microvascular endothelial cell of the liver. Livers from Lewis rats were subjected to 30, 45 and 60 min of warm (37 degrees C) no flow ischemia that was followed by a standard reperfusion period lasting 45 min. Purine nucleoside phosphorylase was measured at the end of the no flow ischemia and reperfusion periods as was superoxide generation (O2-). Bile production was monitored throughout the no flow ischemia and reperfusion periods. Control perfusions were carried out for 120 min. A significant rise in purine nucleoside phosphorylase levels as compared with controls was observed at the end of ischemia in all the three groups. The highest level, 203.5 +/- 29.2 mU/ml, was observed after 60 min of ischemia. After the reperfusion period, levels of purine nucleoside phosphorylase decreased in the 30- and 45-min groups 58.17 +/- 9.66 mU/ml and 67.5 +/- 17.1 mU/ml, respectively. These levels were equal to control perfusions. In contrast, after 60 min of ischemia, levels of purine nucleoside phosphorylase decreased early in the reperfusion period and then rose to 127.8 +/- 14.8 mU/ml by the end of reperfusion (p less than 0.0001). Superoxide generation at the beginning of reperfusion was higher than in controls with similar values observed at the end of 30, 45 and 60 min of ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Induction of labour: the effect of vaginal prostaglandin or i.v. oxytocin--a matter of time only?

Ninety-one pregnant women with unfavourable cervix (Bishop score no higher than 6) were randomly allocated to induction of labour with either prostaglandin E2 suppositories 2.5 mg 1-2 a day or i.v. oxytocin 4-32 mU/min. The induction procedure was carried on for 2 days. For statistical comparison of efficacy, life table analysis and the logrank test were used with vaginal delivery as the aimed 'event'. Prostaglandin suppositories were more efficient after 12 h (p less than 0.025) and 24 h (p less than 0.005), whereas no difference in efficacy was observed after 48 h. Vaginal delivery was obtained within 48 h in 74% of the women in the prostaglandin group and in 70% in the oxytocin group. No difference was observed in methods of delivery or neonatal Apgar scores, though, in neonates delivered vaginally within 2 days, lowered umbilical artery blood pH values were found after prostaglandin E2 suppositories (p less than 0.05). The patients attitude toward the method of induction was highly in favour of the prostaglandin suppositories. Prostaglandin E2 suppositories are considered excellent for induction of labour if delivery has to be within 24 h, whereas the two methods are equally effective after 48 h.

Administration, Intravaginal↗
PubMed1990

Mucosal proliferation characteristics in ureterosigmoidostomy: effect of calcium supplement.

Ureterosigmoidostomy, frequently performed in children for urinary diversion, is a known premalignant condition. Dietary calcium supplements have been shown to normalize mucosal proliferative patterns in other human premalignant colonic conditions, which might decrease the risk of cancer. However, calcium supplementation has not been investigated in ureterosigmoidostomy. We used a rat model to study the effects of increased dietary calcium on the progression to carcinoma in ureterosigmoidostomy. Twenty-five Wister rats underwent ureterosigmoidostomy by anastomosis of bladder trigone and ureters to sigmoid, and were divided into two groups: group 1, regular diet (14); and group 2, calcium supplemented (2%) diet (11). All animals received the diet for 9 months. At death the anastomosis was weighed and examined histologically. In addition, ornithine decarboxylase (ODC), an enzyme involved in polyamine synthesis that becomes elevated in neoplastic and proliferative disorders, was determined at the anastomosis and 8 cm proximal (normal colon). All animals developed proliferative metaplastic polyposis at the anastomosis. Tumor weights were 2.6 +/- 1.1 g for group 1 and 4.8 +/- 1.2 g for group 2 (P less than .05). The ODC levels were: group 1, normal colon 78.2 +/- 15.6 and tumor 321.3 +/- 58.8 (P less than .002); and group 2, normal colon 425.8 +/- 65.4 and tumor 568.0 +/- 40.9 (P = NS). The difference between group 1 normal colon and group 2 normal colon was significant (P less than .001), as was group 1 tumor and group 2 tumor (P less than .02).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Long-term survival in an infant with urethral atresia.

Complete urethral atresia is an anomaly that previously was incompatible with life. We report on a surviving infant with this anomaly. As a fetus urinary decompression was accomplished with a vesicoamniotic shunt. Peritoneal dialysis was initiated shortly after birth and at 9 months supramembranous scrotal inlay urethroplasty was performed to provide for egress of urine from the bladder. A maternal renal allograft was performed when he was 12 months old. When the patient was 3 1/2 years old he had normal renal function and emptied the bladder to completion through the reconstructed urethra. Although mildly delayed, he continues to progress with all developmental milestones.

Cystostomy↗
PubMed1990

Guidelines for description of immunoassay kits.

A provisional recommendation in order to improve manufacturers' and marketers' information to users of immunoassay kits has been compiled by a Nordic Clinical Chemistry project working group.

Chemistry, Clinical↗
PubMed1990

Parthenogenesis in Xenopus eggs requires centrosomal integrity.

Xenopus eggs are laid arrested at second metaphase of meiosis lacking a functional centrosome. Upon fertilization, the sperm provides the active centrosome that is required for cleavage to occur. The injection of purified centrosomes mimics fertilization and leads to tadpole formation (parthenogenesis). In this work we show that the parthenogenetic activity of centrosomes is inactivated by urea concentrations higher than 2 M. The loss of activity is correlated with a progressive destruction of the centriolar cylinder and extraction of proteins. This shows that centrosomes are relatively sensitive to urea since complete protein unfolding and solubilization of proteins normally occurs at urea concentrations as high as 8-10 M. When present, the parthenogenetic activity is always associated with a pelletable fraction showing that it cannot be solubilized by urea. The parthenogenetic activity is progressively inactivated by salt concentrations higher than 2 M (NaCl or KCl). However, only a few proteins are extracted by these treatments and the centrosome ultrastructure is not affected. This shows that both parthenogenetic activity and centrosomal structure are resistant to relatively high ionic strength. Indeed, most protein structures held by electrostatic forces are dissociated by 2 M salt. The loss of parthenogenetic activity produced at higher salt concentrations, while the structure of the centrosome is unaffected, is an apparent paradox. We interpret this result as meaning that the native state of centrosomes is held together by forces that favor functional denaturation by high ionic strength. The respective effects of urea and salts on centrosomal structure and activity suggest that the centrosome is mainly held together by hydrogen and hydrophobic bonds. The in vitro microtubule nucleating activity of centrosomes can be inactivated at salt or urea concentrations that do not affect the parthenogenetic activity. Since egg cleavage requires the formation of microtubule asters, we conclude that the extracted or denatured microtubule nucleating activity of centrosomes can be complemented by components present in the egg cytoplasm. Both parthenogenetic and microtubule nucleating activities are abolished by protease treatments but resist nuclease action. Since we find no RNA in centrosomes treated by RNase, they probably do not contain a protected RNA. Taken together, these results are consistent with the idea that the whole or part of the centrosome structure acts as a seed to start the centrosome duplication cycle in Xenopus eggs.

Animals↗
PubMed1990

An improved passive activated C collector for measuring environmental 222Rn in indoor air.

A modified version of an activated C monitor has been developed for the time-weighted average measurement of 222Rn for periods ranging from 1-7 d. The new collector consists of a metal can containing 50 g of activated C with a sintered metal filter covering the 3.2-cm diameter sample port in its lid. The new configuration reduces the adsorption and desorption rate of both 222Rn and water vapor by a factor of 4-5, as compared to an open-faced canister. The device measures the average 222Rn concentration accurately, even if the 222Rn concentration varies by more than a factor of 10. For practical situations encountered indoors, the modified collector yields results that are accurate to within +/- 10%. The integration time constant of the collector, tested at relative humidities ranging from 23-75%, is 9-11 d, which is more than three times longer than that of existing diffusion barrier collectors. It is simple to use, inexpensive (total cost of materials is +3.50), maintenance-free, easily sent and returned in the mail (total weight = 100 g), and is reusable for multiple exposures after simple regeneration by heating. The lower limit of detection for a 10-min counting interval is 7 Bq m-3 (0.2 pCi L-1) when counted within 3 d after the end of exposure.

Adsorption↗
PubMed1990

[Tendon rupture in chronic kidney insufficiency--"uremic tendonopathy"? A literature-supported documentation of 3 cases].

This is a report on three cases with spontaneous ruptures of major tendons of the lower extremities. In two cases ruptures occurred in the quadriceps tendon, one of them bilaterally, and in one case in the Achilles' tendon. All patients suffered from chronic renal failure and were treated by long-term hemodialysis. Coincidentally secondary hyperparathyroidism was noticed twice. The pathophysiological relation between chronic renal failure and spontaneous tendon rupture is still unknown. An "uremic tendopathy" is discussed.

Achilles Tendon↗
PubMed1989

[Lymphocyte subpopulations in patients with skin basalioma of the trunk].

In 11 male patients with histologically proven basal cell epithelioma of the trunk, we studied the distribution of peripheral lymphocyte subsets. All of the patients revealed pathological T-cell subsets, 6 of them showing reduced numbers of CD8 and 5 decreased numbers of CD 4 cells. 2 patients had taken arsenic; in 2 patients we diagnosed a further tumor of some other origin.

Adult↗
PubMed1989

[Cardiotocographic monitoring of deliveries. A prospective comparative study of 2 types of electrodes].

The number of electrodes employed, the frequency of reapplication, the technical quality of monitoring and the complications of use of spiral electrodes and Copeland electrodes for cardiotocographic monitoring of deliveries are assessed in a prospective randomized investigation. The number of electrodes employed and the frequency of reapplications were significantly lower employing Copeland electrodes. Similarly, the electrode signal was significantly better as assessed by the percentage of the duration of monitoring in which the cardiotocogram did not register during the second stage of labour on account of poor electrode signals. No differences were found in the frequencies of complications or subjective discomfort in the mother on employing the two types of electrodes.

Adult↗
PubMed1989

Fetal weight estimation in twin pregnancies.

In this study the fetal weight was estimated by ultrasound measurements of the biparietal (BPD) and abdominal diameters (AD) in 154 consecutive twin pregnancies. In 80 twins an attempt to estimate fetal weight was made 0-4 days before delivery (26% of all twins examined). In 84% (67 infants) it was possible to estimate the fetal weight using the formula (0.0108 X AD1.72 X BPD0.99). 60% of the birth weights deviated less than 10% from the estimated fetal weight and 83% deviated less than 15%. The prediction error was nearly constant, expressed as percent of actual weight in the different weight groups (8.5-9.8%). In 19 LGA infants, 69% of the birth weights deviated less than 10% from the estimated fetal weight and 70% deviated less than 15%.

Body Weight↗
PubMed1989

A monoclonal antibody-based immunoradiometric assay for low molecular weight insulin-like growth factor binding protein/placental protein 12.

We describe a sensitive immunoradiometric assay for insulin-like growth factor binding protein/Placental Protein12 (IGF-BP/PP12) using monoclonal antibodies. This assay has a detection limit of 0.25 micrograms/l IGF-BP/PP12. Parallel dose response curves were obtained with purified IGF-BP/PP12, amniotic fluid, decidual cytosol extract, and serum. The assay is reproducible (intra-assay variation 4.3-8.2% and interassay variation 9.7-11.1%) and fast (less than 5 hours). A crossreactivity of less than 0.01% for all other proteins tested reflects high specificity. Using this method the mean serum IGF-BP/PP12 concentration in healthy women was 5.2 micrograms/l. During pregnancy, the mean IGF-BP/PP12 at 7-11 weeks was 43.3 micrograms/l, and at 36-40 weeks 121 micrograms/l. After early pregnancy termination the serum IGF-BP/PP12 decreased rapidly reaching a mean level of 8 micrograms/l within 4 days.

Amniotic Fluid↗
PubMed1989

Intraoperative blood transfusions in highly alloimmunized patients undergoing orthotopic liver transplantation.

Intraoperative blood requirements were analyzed in patients undergoing primary orthotopic liver transplantation and divided into two groups on the basis of panel reactive antibody of pretransplant serum measured by lymphocytotoxicity testing. One group of highly sensitized patients (n = 25) had PRA values of over 70% and the second group of patients (n = 26) had 0% PRA values and were considered nonsensitized. During the transplant procedure, the 70% PRA group received considerably greater quantities of blood products than the 0% PRA group--namely, red blood cells: 21.1 +/- 3.7 vs. 9.8 +/- 0.8 units (P = 0.002), and platelets: 17.7 +/- 3.2 vs. 7.5 +/- 1.5 units (P = 0.003). Similar differences were observed for fresh frozen plasma and cryoprecipitate. Despite the larger infusion of platelets, the blood platelet counts in the 70% PRA group were lower postoperatively than preoperatively. Twenty patients in the 70% PRA group received platelet transfusions, and their mean platelet count dropped from 95,050 +/- 11,537 preoperatively to 67,750 +/- 8,228 postoperatively (P = 0.028). In contrast, nearly identical preoperative (84,058 +/- 17,297) and postoperative (85,647 +/- 12,445) platelet counts were observed in the 17 0% PRA patients who were transfused intraoperatively with platelets. Prothrombin time, activated partial thromboplastin time, and fibrinogen levels showed no significant differences between both groups. These data demonstrate that lymphocytotoxic antibody screening of liver transplant candidates is useful in identifying patients with increased risk of bleeding problems and who will require large quantities of blood during the transplant operation.

Adult↗
PubMed1989

Propagation of alloreactive lymphocytes from histologically negative endomyocardial biopsies from heart transplant patients. Association with subsequent histological evidence of allograft rejection.

Endomyocardial biopsies from heart transplant patients were cultured in vitro in the presence of Interleukin-2 and irradiated feeder cells to propagate graft-infiltrating lymphocytes. A correlation was seen between the frequency of lymphocyte growth and the degree of cellular infiltration of the biopsies. In this study, 43 of 113 (38%) histologically negative biopsies obtained from 55 patients during the first month post-transplant yielded lymphocyte cultures. The cumulative incidence of subsequent histological rejection was considerably higher in patients with such "grower" biopsies than in patients with "nongrower" biopsies. In the grower group, we were able to obtain data on alloreactivity of 32 lymphocyte cultures assayed by primed lymphocyte testing (PLT). The presence of donor-specific PLT reactivity in the cultured lymphocytes was associated with an additional risk for subsequent histological rejection. These findings suggest that the in vitro culturing of histologically negative endomyocardial biopsies will identify patients at increased risk for developing heart transplant rejection.

Biopsy↗