Biomedical subjects

H Schmidt

Publications and source records attributed to H Schmidt.

At least 649 records · Page 36Linked to original sources

PubMed1990

[Diagnosis of lysosomal storage diseases. Pathomorphologic and biochemical possibilities].

Optical light and electron microscopy were used in studies into two cases of infantile GM2-gangliosidosis. The results are reported in this paper. The correlation has been evident between histological and ultrastructural findings. Reliable delimitation between two different variants of infantile GM2-gangliosidosis was achieved through biochemical investigation of postmortally cultured skin fibroblasts. A classical form with isolated hexosaminidase-A defect (Tay-Sachs disease) was distinguished from a second variant with complete defect of both isoenzymes of hexosaminidase (Sandhoff's disease). Biochemical investigation of postmortally cultured fibroblasts today has become indispensable to enlargement of autopsy findings from other storage diseases, as well.

Brain↗

PubMed1990

[Quantitative determination of phenoloxidase (EC 1.14.18.1). Spectrophotometry measurement of the activity of mushroom and potato tyrosinase].

With dopa as substrat the enzyme were incubated 20 min in 0.1 M phosphate buffer, pH 6.8. After that the activity was detected at wavelengths of 313 and 492 nm using a layer thickness of 10 mm. Employing this conditions higher activities were estimated in the commercial preparates as indicated. The high sensitivity commends this standardized method to use in melanoma research.

Basidiomycota↗

PubMed1990

Lymphatic tissue changes in AIDS and other retrovirus infections: tools and insights.

Based on immunohistochemistry, in situ hybridization, and electron microscopy, lymphatic tissue changes in human immunodeficiency virus (HIV) and other retroviral infections represent different stages of a dynamic process progressing from hyperplasia to atrophy. The germinal centers (GC) function early as a virus reservoir in both HIV and feline leukemia virus infection, which also produces lymphadenopathy, severe immune impairment, and death from opportunistic infections. Core proteins of HIV can be detected on the surface of follicular dendritic cells, electron microscopy reveals cell-free HIV and virus replication in the same location, and in situ hybridization shows that the majority of cells with mRNA of HIV can be found in germinal centers (GC). Double immunohistochemical labeling of lymphocyte populations suggests that one of the most important events in HIV lymphadenitis with explosive follicular hyperplasia is the accumulation of CD8+CD45R0+ lymphocytes in the lymph nodes. Their clustering in the vicinity of the FDC network could play a key role in disintegration of GC and lymphocyte depletion as the disease progresses.

Acquired Immunodeficiency Syndrome↗

PubMed1990

Bone marrow transplantation in comparison with conventional therapy in children with adult type chronic myelogenous leukemia.

From 1983 to 1988 14 patients under 16 years of age with adult type chronic myelogenous leukemia (CML) in chronic or blastic phase were treated by allogeneic bone marrow transplantation (BMT) in our center. These comprise 54% of all patients under 16 years of age grafted for this disease in FRG. These BMT patients were compared with 24 similar patients treated conventionally with busulfan and/or hydroxyurea in various centers. The probability of an event-free survival 5 1/2 years after BMT was 0.61 (SD 0.16); the estimated probability of survival for 3-8 years after diagnosis in the group treated by GMT was 0.78 (SD 0.14) vs 0.55 (SD 0.12) for the non-BMT group. The difference is not significant. In the BMT group only two patients died of transplant-related complications. The non-BMT patient with the longest survival period died recently 10 years after diagnosis. For children with adult type CML, BMT is a safe and effective treatment, and should be recommended if there is an HLA compatible sibling donor or even a fully compatible unrelated donor. However, for a more conclusive comparison between bone marrow transplantation and conventional treatment a longer observation period and larger patient numbers are necessary.

Adolescent↗

PubMed1990

[The effect of continuous arteriovenous hemofiltration on the pharmacokinetics of azlocillin in anuric patients].

The influence of continuous arteriovenous hemofiltration on the pharmacokinetics of azlocillin was examined in eight anuric intensive care patients, each of whom received a short infusion of 5.0 g azlocillin. Azlocillin concentrations in blood were measured simultaneously in the afferent and efferent loops of the amicon Dia 20 hemofilter and in the ultrafiltrate by means of an agar diffusion technique. Pharmacokinetic parameters were calculated by a computer program based on a two compartment model. We found that the elimination half-life of azlocillin ranged between 218.8 and 342.8 min, a result comparable to those of other investigators, who found similar elimination half-lives in anuric patients. During an observation period of 270 min, only 0.2-1.1% of the total dose of azlocillin was eliminated by way of the hemofilter. Apparently, continuous arteriovenous hemofiltration has no clinically relevant implications for the dosage or the dosage intervals of this antibiotic. On the other hand, azlocillin was taken up by the amicon Dia 20 hemofilter during the infusion. After the infusion was stopped the filter released azlocillin to blood and ultrafiltrate. The ratio of concentration in ultrafiltrate to plasma concentration in the afferent loop of the hemofilter was higher for about 45 min during the elimination phase than during the infusion. The volume of distribution was much larger (mean 28.5 l) than that found by other investigators. Therefore, the amicon-Dia 20 hemofilter seems to function as an additional distribution space.(ABSTRACT TRUNCATED AT 250 WORDS)

Anuria↗

PubMed1990

[Focal peliosis of the adult liver in combination with glycogenosis type I (v.Gierke). A case report and review of the recent literature].

Peliosis hepatis is a condition characterized by blood-filled lesions in the liver that can be localized or diffuse in distribution. The predisposing factors for this condition include treatment with anabolic steroids, chemotherapeutic and oral contraceptive agents, catabolic metabolic conditions (e.g., hypoglycemia) and certain immunological disorders. This disease probably represents a non-specific immunological response to a variety of noxious agents and has been successfully induced in experimental animals. The increased tendency towards liver rupture following blunt trauma and resuscitation procedures may have important medicolegal consequences. We present a case of peliosis hepatis in a patient with type I glycogen storage disease (von Gierke).

Adult↗

PubMed1990

[Clearance rate of gingiva and content of collagen of inflammated and clinically non-inflammated papilla interdentalis].

UNLABELLED: The gingiva vessel function has been defined by gingivitis (A), clinical sound gingiva without (B) and with loss in attachment (C) as well as the collagen fraction by biopsy material. The division of the probands at the age between 20 and 24 years into groups has been carried out after checking the SBI, PII (Silness/Loe) and the loss of attachment of the teeth 43-33. The vessel function has been found out through the impulse rate of the gingiva Xenon-133-clearance by calculating the clearance rates (CR) (groups: A1 n = 15; B1 n = 18; C1 n = 16). The vestibular interdental papillae have been elaborated in a second study for finding out the collagen fractions with the Stegemann method modified by Woessner (groups: A2 n = 18; B2 n = 10; C2 n = 12). The statistical reliability has been checked by the t-test (F-test) and the u-test by Mann and Whitney. RESULTS: In the clearance study the CR in group A1 are higher and in group C1 lower than in group B1. In the second study the increased collagen solubility in group A2 by inflammation is confirmed, in group C2 a significant higher share in unsoluble collagen and total collagen has been defined than in group B2.

Adult↗

PubMed1990

[NMR tomography of vena cava thrombi: clinical significance in the differential diagnosis and therapy].

31 patients with advanced renal cell carcinoma underwent abdominal MRI which were examined by an independent experienced radiologist and compared with the intraoperative findings. 12 of 13 vena caval tumor thrombi were diagnosed correctly, 1 small tumor thrombus in a case with large retroperitoneal lymph nodes compressing the vena cava could not be detected. The extension of the tumor in the vena cava could exactly be described in topographic relation to liver, diaphragm and right atrium which is important for planning the operative procedure.

Carcinoma, Renal Cell↗

PubMed1990

Metabolism of purine and pyrimidine compounds in erythrocytes of tumor-bearing mice.

The pattern of purine and pyrimidine derivatives was studied in the erythrocytes of C3HA and ICR mice during Hepatoma 22 and Ehrlich ascites tumor cell growth. Concentrations of purine nucleotides, nucleosides and nucleobases of host erythrocytes were changed after the implantation of the tumors. The host erythrocytes markedly concentrated adenine and guanine nucleotides both during logarithmic and plateau phase of tumor growth (5th and 11-12th days after inoculation of the tumor). The contents of nucleosides and nucleobases in the red blood cells were decreased during the logarithmic growth phase but restored within the plateau phase.

Animals↗

PubMed1989

[Rapid diagnosis of acute tonsillitis caused by streptococcus group A].

In general practice, a material of 202 patients seeking advice on account of difficulty in swallowing were included consecutively in an investigation with the object of assessing the value of a rapid test, Respiralex, for the diagnosis of group A streptococci as compared with culture. The true positive and negative diagnostic frequencies were 0.89 and 0.94, respectively. Absence of agreement was found most frequently when culture rendered poor growth. It is concluded that Respiralex is such a reliable method of examination in the diagnosis of group A streptococci, that it is recommended for use in general practice and that culture is only necessary in patients with negative Respiralex tests and pronounced objective signs of streptococcal tonsillitis.

Acute Disease↗

PubMed1989

Synthesis of different nucleoside 5'-diphospho-sulfoquinovoses and their use for studies on sulfolipid biosynthesis in chloroplasts.

6-Sulfo-alpha-D-quinovopyranosyl phosphate was reacted with different nucleoside monophosphate morpholidates to form ADP-, CDP-, GDP- and UDP-sulfoquinovose. Analytical and preparative HPLC of these nucleotides was performed on reversed-phase columns using volatile buffer systems as eluant. The isolated compounds were characterized by NMR spectroscopy (except the CDP derivative) and used for an investigation of sulfolipid biosynthesis by chloroplasts. For this purpose intact spinach chloroplasts were biosynthetically preloaded with radioactive diacylglycerol to provide a sulfoquinovosyl acceptor. When sulfosugar nucleotides were added to such prelabelled intact organelles, the background levels of sulfolipid biosynthesis did not rise. On the other hand, after osmotic shock of prelabelled chloroplasts sulfolipid labelling was significantly increased by the addition of UDP- or GDP-sulfoquinovose. The same stimulation was observed with isolated envelope membranes, and UDP-sulfoquinovose proved to be twice as active as the GDP derivative. From these results it was concluded that the final step in sulfolipid biosynthesis is catalyzed by a UDP-sulfoquinovose: 1,2-diacylglycerol 3-O-alpha-D-sulfoquinovosyltransferase. This chloroplast enzyme cannot use exogenously supplied sulfosugar nucleotides, which as membrane-impermeable compounds are expected to be formed in vivo within chloroplasts.

Bacterial Proteins↗

PubMed1989

[Transplantation of bone marrow from unrelated donors in chronic myeloid leukemia].

Bone marrow transplantations in four patients (aged 8-28 years, median 27 years) with chronic myeloid leukaemia (CML) were performed from unrelated donors who were HLA-identical and MLC-negative. One patient was in the stage of refractory blast crisis, one in a chronic phase, and two in the second chronic phase. Conditioning treatment consisted of fractionated radiation and administration of cyclophosphamide; in the patients with their second chronic phase additionally etoposide. Cyclosporin A and methotrexate were administered to prevent graft versus host reaction. The patient in the blast crisis died on day 12 after transplantation of Candida pneumonia. The other three patients are still alive 128, 306 and 530 days, respectively, after transplantation, only a mild form of graft versus host disease having occurred. It is suggested that for patients younger then 50 years with CML in the chronic phase an unrelated donor should be searched for in the absence of a familial donor.

Bone Marrow Transplantation↗

PubMed1989

Interference of electron transport inhibitors with desaturation of monogalactosyl diacylglycerol in intact chloroplasts.

Isolated intact chloroplasts are able to desaturate fatty acids in newly synthesized monogalactosyl diacylglycerol. By analogy with other systems, this desaturation might be expected to involve electron carriers. The effects of electron transport inhibitors on chloroplast lipid-linked desaturation were therefore investigated. Because desaturation occurs in the dark and is not inhibited by compounds specifically blocking photosystem II, it appeared that the photosystems themselves did not participate. Several compounds that prevent enzymatic reoxidation of plastoquinol in thylakoid membranes at the Qz site or withdraw electrons from this lipophilic electron carrier inhibited desaturation in the dark. This inhibition could not be reversed by adding chemicals that donate electrons to photosystem I, indicating that carriers past the cytochrome b/f complex were not involved. Inhibitors of cyclic electron transport interfered with desaturation only at rather high concentrations or not at all. Additional compounds that block the reduction of quinones were slightly inhibitory. Dithioerythritol and KCN also inhibited desaturation, although their exact mode of action is unknown. Dinitrophenyl-iodonitrothymol (DNP-INT), stigmatellin, and myxothiazol did not block desaturation at concentrations that inhibited photosynthetic electron flow through the Qz site very efficiently. Therefore, these results argue against an involvement of the Qz site in desaturation. Accordingly, the inhibition by the other compounds seemingly interfering at the same site as well as that by electron acceptors could be due to interference at a different redox step in desaturation. In vitro these compounds function also as electron acceptors in diaphorase reactions catalyzed by ferredoxin:NADP oxidoreductase.

Acylation↗

PubMed1989

Osteocalcin serum levels in patients following renal transplantation.

Osteocalcin serum levels reflect bone turnover. In renal insufficiency secondary hyperparathyroidism and reduced renal clearance might be responsible for elevated serum levels of osteocalcin. Renal transplantation might improve renal osteodystrophy and therefore could influence osteocalcin serum levels. We determined the influence of renal transplantation on osteocalcin levels in 37 consecutive patients (25m/12f) by RIA. Blood samples were collected prior to, 3 days, 28 days, 6 months and 12 months after renal transplantation. Prior to renal transplantation osteocalcin levels were significantly elevated (mean +/- s: 23.4 +/- 12.8 ng/ml) compared to healthy volunteers (4.1 +/- 1.4 ng/ml). Following renal transplantation osteocalcin decreased significantly (9.4 +/- 8.9 ng ml) 3 days and (7.1 +/- 7.8 ng/ml) 28 days. However, 6 and 12 months following renal transplantation the mean osteocalcin level increased again (8.3 +/- 5.7 ng/ml, 12.1 +/- 15.4 ng/ml). At 6 months 11 and at 12 months only 6 of 37 patients had osteocalcin levels in the normal range. 12 months following renal transplantation 21 out of 37 patients with elevated osteocalcin levels had parathyroid hormone levels above the normal range. Additionally to increased osteocalcin levels patients prior to renal transplantation had elevated alkaline phosphatase. Alkaline phosphatase had following renal transplantation a similar pattern as osteocalcin with initial decrease and secondary increase 6 and 12 months after renal transplantation. Parathyroid hormone was elevated in all patients before renal transplantation. Following renal transplantation mean parathyroid hormone levels tell significantly, however remained above normal range in 57% of these 37 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1989

Silica exposure and silicosis among Ontario hardrock miners: II. Exposure estimates.

An epidemiological investigation was carried out to determine the relationship between silicosis in hardrock miners in Ontario and cumulative exposure to silica (free crystalline silica--alpha quartz) dust. This second report describes a side-by-side air-sampling program used to derive a konimeter/gravimetric silica conversion curve. A total of 2,360 filter samples and 90,000 konimeter samples were taken over 2 years in two mines representing the ore types gold and uranium, both in existing conditions as well as in an experimental stope in which dry drilling was used to simulate the high dust conditions of the past. The method of calculating cumulative respirable silica exposure indices for each miner is reported.

Environmental Exposure↗

PubMed1989

Antitumor activity in vitro in chronic myelogenous leukaemia revealed after treating peripheral cells with cytosine arabinoside.

Cytosine arabinoside (Ara-C) treatment of peripheral blood mononuclear cells from 12/12 chronic-phase chronic myelogenous leukaemia (CML) patients revealed a proliferative response stimulated by their untreated leukaemic cells. Specific recognition of tumour cells by patients' normal lymphocytes was suggested by the finding that cells of siblings genotypically identical for human leukocyte antigen caused no stimulation. Lymphocytes thus stimulated by tumour cells from one of these patients were cloned by limiting dilution and tested for antileukaemic effects in cytotoxicity and proliferation assays. Cytotoxic lines were isolated that killed autologous CML targets but only a limited number of allogeneic fresh leukaemias or cell lines. These results show that anti-leukaemia effectors can be isolated from chronic-phase CML patients and suggest their potential application in adoptive immunotherapy.

Antigens, Differentiation↗

PubMed1989

Partial correction of defective generation of lymphokine-activated killer cells in patients with chronic myelogenous leukaemia after in vivo treatment with interferon-alpha (Wellferon).

Patients with chronic myelogenous leukaemia (CML) in untreated chronic phase are deficient in their ability to generate lymphokine-activated killer (LAK) cells from peripheral blood mononuclear cells although they possess essentially normal levels of CD16+ and Leu19+ lymphocytes, which do not seem to be actively suppressed by tumour cells. Attempts to enhance LAK cell generation in these patients are reported here. Combining the lymphokines interleukins-2, with -4 and -5 (IL-2, IL-4, IL-5), was not successful; in fact, IL-4 depressed LAK cell induction in both normal donors and CML patients. The phorbol ester 12-O-tetradecanoylphorbol 13-acetate also failed to enhance cytotoxicity of normal donors or patients, and indomethacin was similarly without effect. The only agent found to enhance LAK cell induction by IL-2 in normal donors was interferon-gamma (but not IFN-alpha) and even this modest effect was not seen with the cells of CML patients. Increasing concentrations of IL-2 and/or culture duration also failed to improve LAK cell generation by patients. The only improvement in LAK cell generation was observed in CML patients treated for one or more months with IFN-alpha, where a steady increase of LAK activity with time after initiation of therapy was noted. These results show that the blockade of LAK cell induction in chronic-phase myelogenous leukemia patients is difficult to lift pharmacologically in vitro but possibly susceptible to biological response modifiers in vivo.

Cells, Cultured↗

PubMed1989

Some of the swi genes of Schizosaccharomyces pombe also have a function in the repair of radiation damage.

In Schizosaccharomyces pombe the frequency of mating-type (MT) switching is reduced by mutations in the swi genes. The ten hitherto known swi genes can be subdivided into three classes: Ia, Ib and II. Strains having swi5 (class Ib), swi9 (class II) and swi10 (class II) mutations do not only show reduced MT switching, but also exhibit an increased sensitivity to UV- and gamma-rays. For that reason, 19 previously described rad genes were tested for their effect on MT switching. We found that swi9, "rad10", "rad16" and "rad20" are allelic with each other indicating that the former allocation of these rad mutations to three different genes must have been erroneous. Among the remaining 16 rad genes examined, rad22 seems to be a new class II swi gene. The double mutants swi5 swi9 and swi5 swi10, but not swi9 swi10, are much more sensitive to radiation than the respective single mutants. Thus a cumulative increase in sensitivity occurs only if the mutants belong to different classes; previously the same correlation was found with regard to cumulative effects in MT switching.

DNA Repair↗