Biomedical subjects
Publications and source records attributed to F Sommer.
Observations of intact reconstituted and native collagen fibres were performed with the atomic force microscope. The results are compared between the two types of fibres and with those obtained previously with the electron microscope on freeze-etched or negative stained samples. Some of the findings presented here indicate that the specimens observed in air with the atomic force microscope were still in a hydrated state.
PAF synthesized by or added to the endothelial cell monolayer has as first target the endothelium itself, inducing the expression of GMP-140 on the cell surface and qualitative alterations in the composition of glycocalyx. As seen by ESCA, sulfated chemical groups were significantly reduced after PAF stimulation. This reduction depended on selective loss of sulfated proteoglycans that were released into the supernatant. The alteration of glycocalyx may favor functional exposure of GMP-140 and of PAF on the surface of endothelial cells and may reduce charge repulsive forces between cells. PAF associated with endothelial cell surface has as second target PMNs and stimulates in cooperation with GMP-140, the functional activation of PMN CD11-CD18 adhesion molecules.
Previously, it has been described that the ability of murine Th1 cells to proliferate in response to exogenous interleukin (IL)-2 is blocked when these cells are exposed to immobilized anti-CD3 antibodies. In the present study we examined whether simultaneous triggering of the T cell antigen CD28 can prevent the induction of unresponsiveness to IL-2 in Th1 cells. We report that costimulation of Th1 cells with anti-CD28 monoclonal antibodies (mAb) did not overcome unresponsiveness to IL-2 induced by various amounts of immobilized anti-CD3 antibodies. However, stimulation with anti-CD28 mAb strongly augmented IL-2 and interferon-gamma production in anti-CD3-exposed Th1 cells. Thus, despite the fact that anti-CD28 mAb is a potent costimulus for lymphokine production, signaling through CD28 does not seem to be sufficient to trigger proliferation in Th1 cells activated via the T cell receptor. These data suggest the existence of at least three signals to trigger Th1 cell activation. The first is mediated by ligation of the T cell receptor. One cosignal, delivered by the CD28 molecule, leads to IL-2 production. A third, still undefined, signal is required for proliferation in response to IL-2.
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Soft contact lens (SCL) surfaces were imaged with atomic force microscopy (AFM). High-resolution images of unworn SCL were obtained under nearly physiological medium. We present images of surfaces of collagen bandage lens under dry or aqueous conditions and of SCL of different water content and fabrication processes. Roughness parameters were determined. AFM studies of surfaces of SCL are expected to provide useful information on the hydrogel surfaces.
In continuous Friend leukemia cell exposure to tTAuP, the IC50 was 0.2 microM whereas in cells exposed 15 or 60 min to tTAuP followed by 72 h in drug-free medium the IC50 was 2.2 and 1.3 microM respectively. A combination of tTAuP and cisplatin (CDDP) is shown to be more active than either agent alone. Intracellular accumulation studies analysed by SXRF have shown that to achieve a cytotoxic effect, large concentrations of gold are necessary to accumulate in both the nuclear and cytoplasmic fraction. However, at cytostatic doses (1 microM), tTAuP has no effect on the cell cycle but does affect DNA synthesis. At a higher dose, greater than that necessary to induce cytotoxicity, it produces DNA damage, as observed by alkaline elution method. When cells were exposed to toxic doses of tTAuP (10 microM) in the presence of albumin, cytotoxicity was significantly reduced. Similar results were obtained when cells were co-treated with L-cysteine, dithiothreitol or reduced gluthatione. Reduced cytotoxic effect can be related to the interaction with free thiol groups. According to these data it is concluded that tTAuP is highly effective in vitro; whether it is active in vivo remains to be determined.
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The thermogenic effect of food and the rates of oxidation and storage of nutrients were evaluated by indirect calorimetry in 10 cirrhotic patients and seven normal controls for a 6-hour period, after they had consumed a standard meal supplying 15 kcal/kg body weight with 15%, 30%, and 55% protein, fat, and carbohydrate calories, respectively. Although the thermogenic response to food was not significantly lower in patients than in controls (51.6 +/- 13.5 v 72.2 +/- 8.8 kcal/6 h), patients exhibited a delayed and blunted increment of energy expenditure after the meal intake (P less than .025). The greater part of the glucose load was oxidized in patients (70.2 +/- 3.9% v 50.4 +/- 3.9% in controls; P less than .01), suggesting a defective glucose storage as glycogen. This result could be related to insulin resistance, which was evidenced by a large increase in glucose and insulin levels after the meal intake in patients (P +/- .001). Conversely, lipid oxidation was sharply reduced and de novo lipogenesis occurred in patients, so that the rate of lipid storage was increased. The profiles of circulating levels of catecholamines, thyroid hormones (free thyroxine [FT4] and triiodothyronine [T3]), and glucagon were assayed during the test. Norepinephrine and glucagon levels remained higher in patients throughout the test (P less than .001), whereas thyroid hormones stayed in the same range in the two groups. After an initial increase, glucose levels decreased sharply, inducing an activation of counterregulatory hormones, glucagon, and notably, epinephrine, for which the increment was correlated with the decrease of glucose (r = -.917; P less than .001).(ABSTRACT TRUNCATED AT 250 WORDS)
The thermic effect of food was evaluated in 10 cirrhotic patients and 7 normal controls by indirect calorimetry during 6 hours following intake of a mixed meal supplying 15 kcal/kg of body weight and containing 30, 15 and 55 percent as lipid, protein and carbohydrate calories respectively. The rates of storage and oxidation of nutriments, as well as variations of blood glucose, insulin, plasma lactates, free fatty acids, glycerol, and ketonic corps were also evaluated. The thermogenic response to food was lower (p less than 0.025) and delayed in cirrhotic patients. In cirrhotic patients the rate of glucose oxidation was significantly increased (70.2 +/- 3.9 vs 50.4 +/- 3.9 percent of the glucose load; p less than 0.01) suggesting a defect in glycogen storage. These results can be related to insulin resistance as attested by a larger increase of glucose and insulin levels in cirrhotics than in controls (p less than 0.001 and p less than 0.001, respectively). Compared with controls, lipolysis in cirrhotic patients was more suppressed as shown by a sharper decrease of free fatty acids and glycerol levels (p less than 0.001 and p less than 0.02, respectively). Furthermore, the rate of lipid oxidation decreased more in cirrhotic as compared with controls (p less than 0.001) before becoming completely suppressed. De novo lipogenesis appeared between the 2nd and 4th hours. Consequently, the rate of lipid oxidation was significantly reduced in cirrhotic vs controls (14.3 +/- 5.0 vs 30.5 +/- 3.7 percent of the lipid load; p less than 0.02) showing an increased rate of lipid storage.(ABSTRACT TRUNCATED AT 250 WORDS)
Proliferation of BCL1 cells, generally used for the measurement of murine interleukin (IL)5, is shown to be strongly suppressed by interferon (IFN)-gamma. This effect can be abrogated by the addition of anti-IFN-gamma antibodies. Thus, the IL5 activity of culture supernatants derived from T cells simultaneously producing IFN-gamma and IL5, can only be seen with BCL1 cells in the presence of anti-IFN-gamma antibodies. If anti-IFN-gamma antibodies are omitted, T cells which produce both, IFN-gamma and IL5, may mistakenly be grouped into the TH1 subtype producing only IFN-gamma, but no IL5.
CD4-positive T cell clones with specificity for the protozoan parasite Leishmania major (L. major) of both the protective TH1 and the disease-exacerbating TH2 subtype were isolated from a diseased L. major-infected mouse of the susceptible BALB/c strain. In addition, TH2 cells were isolated from the lesion-draining lymph nodes of an animal clinically healed nine months after sublethal irradiation and subsequent infection. Our data support the notion that the differential outcome of the disease in non-irradiated versus irradiated BALB/c mice reflects the regulation of the two CD4+ T cell subsets. These data also argue against the possibilities that: 1) TH2 cells and their precursors are totally eliminated by irradiation and that 2) TH2 cells are capable of completely hindering the expansion of TH1 cells in diseased animals.
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After having been submitted to mainly transurethral electroresection, a not selected group of patients (n = 143) with bladder carcinomas of different, mostly advanced stages (TIS and TI = 4 patients, T2 = 33, T4 = 13) was irradiated with the circular accelerator (betatron) applying a telecentric pendulum method with a small angle. The total dose of 5100 rd (51 Gy) which we wanted to achieve hitherto was administered to 129 patients; 14 patients received a lower dose. Radiogenic complications were unimportant. Only 25 patients presented a cystitis during and after radiotherapy which disappeared after treatment. A contracted bladder as final condition was seen in 5.5% (8 patients) of all irradiated patients. The three-year survival rate of all stages was 44.9%, the five-year survival rate of 31.3%.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
A report is given of the results of histopathologic examinations of subsequent biopsies carried out on 54 patients with prostate carcinomas and of the clinical development of the prostate carcinomas of 89 patients. All these patients were treated only by therapeutic radiology. Then follows a discussion whether the radiation or the hormone therapy has the preponderant values. The possible complications of the two therapy methods are compared.