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Biomedical subjects

D J Stechschulte

Publications and source records attributed to D J Stechschulte.

At least 19 recordsLinked to original sources
PubMed1992

Comparison of normal and rachitic rat matrix vesicles.

Accumulated information about MVs in PO4-deficient rachitic rats shows them to be normal in most aspects. Both normal and rachitic MVs show the same ultrastructural features and selective spatial distribution in the growth plate, and both contain a nearly identical array of major proteins. Rachitic and normal MVs show the same avidity to calcify in vivo and in vitro. A slightly greater specific activity of ALP in rachitic MVs may enhance their calcifiability. We conclude that rachitic rat MVs are essentially 'normal' and can be used as an adequate model to study the mechanism of biological calcification.

Alkaline Phosphatase↗
PubMed1992

Presence and specific concentration of carbonic anhydrase II in matrix vesicles.

Matrix vesicles were isolated from the epiphyseal growth plates of normal weanling rats, and the presence of carbonic anhydrase II was demonstrated by Western blotting and ultrastructural immunolocalization using the immunogold technique. Total carbonic anhydrase activity was assayed and showed a statistically significant increase in matrix vesicles as compared to normal rat chondrocytes derived from the same growth plates. These results are the first to establish the presence of carbonic anhydrase in matrix vesicles.

Animals↗
PubMed1991

Increased matrix vesicle protein in rachitic rat epiphyseal growth plates.

Extracellular, membrane-bound vesicles are widely regarded to be the initial site of calcification in a variety of tissues under normal and pathological conditions. Alkaline phosphatase is believed to play a vital role in this process by hydrolysing ester phosphates or mineral inhibitors, e.g. inorganic phosphates. In the present study, matrix vesicles from normal and rachitic rat growth plates were compared with regard to specific activity of alkaline phosphatase, total vesicle protein and ultrastructural distribution of alkaline phosphatase activity. Matrix vesicles were released from normal or rachitic growth plates by collagenase digestion and isolated by differential centrifugation. Enzyme cytochemical localization involving a cerium capture method was performed on vesicles collected by vacuum filtration on Millipore filters. SDS gels and Western blots on fractions of both normal and rachitic matrix vesicles showed major proteins to be almost identical and confirmed the presence of alkaline phosphatase in both. Total matrix vesicle protein ((mg total matrix vesicle protein/rat) x 10(2)) per rat was significantly greater for the rachitic animals (9.0 +/- 2.0 vs. 4.0 +/- 1.0), P less than 0.0001. Alkaline phosphatase specific activity (units alkaline phosphatase/mg vesicle protein) in the rachitic and normal matrix vesicles was 25.29 +/- 9.36 and 18.78 +/- 3.37, respectively (0.05 less than P less than 0.1). Electron dense cerium phosphate deposits were localized to the outer membrane surface of matrix vesicles derived from both types of rats. This data, the first to quantify the relationship between rickets, matrix vesicle protein and alkaline phosphatase specific activity, suggests that matrix vesicles from rachitic and normal rats have biochemical and morphological similarity.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗
PubMed1991

Potentiation of antigen-induced mast cell activation by 1-34 bovine parathyroid hormone.

Peptides such as parathyroid hormone (PTH), somatostatin, and gastrin have been reported to stimulate mast cell mediator release. Preincubation of rat serosal mast cells with synthetic 1-34 bovine parathyroid hormone (1-34bPTH) significantly enhanced antigen-induced 5-hydroxytryptamine (5-HT) release. Enhancement of 5-HT release by 1-34bPTH was dose dependent between 5 and 2000 nM. In the absence of antigen, mean net 5-HT release was less than 1% when naive or passively sensitized mast cells were incubated with 1000 nM 1-34bPTH for time intervals up to 90 min. These findings indicate that 1-34bPTH, at relatively low concentration, potentiates antigen-induced 5-HT release from mast cells.

Animals↗
PubMed1990

Inhibition of mediator release in systemic mastocytosis is associated with reversal of bone changes.

A 59-year-old male presented with systemic mastocytosis with extensive skeletal involvement resulting in vertebral compression fractures and bone pain. Histomorphometric analysis of bone revealed increased mast cells, elevated static parameters of bone resorption, and low bone formation. Serum calcium, phosphorus, and alkaline phosphatase were normal; however, serum 1,25-dihydroxyvitamin D3 and osteocalcin levels were low. Histamine levels in plasma and urine were elevated. Following therapy with ketotifen, the patient had resolution of bone pain along with decreased flushing and pruritus. Elevated plasma and urine histamine levels normalized, as did 1,25-dihydroxyvitamin D3 and osteocalcin levels. Indices of low bone formation improved on therapy. Eroded surfaces improved but remained elevated. This case is the first demonstration that bone symptoms and histomorphometric change in systemic mastocytosis are reversed with inhibition of mast cell degranulation. The role of mast cells and their products in bone metabolism is poorly understood, but the therapy of bone disease in systemic mastocytosis should include inhibition of the release of mast cell products along with the use of histamine antagonist.

Bone Resorption↗
PubMed1990

Secondary biliary cirrhosis as a consequence of graft-versus-host disease.

A 9-yr-old white girl with acute monoblastic leukemia received an HLA-identical, mixed lymphocyte culture-nonreactive bone marrow transplant from her sister. Twelve days after the transplant, a diffuse, pruritic, maculopapular rash involving the entire body surface (including the palms and soles) developed. Subsequent skin biopsy was consistent with cutaneous graft-versus-host disease, and biopsy-proven hepatic involvement manifested by severe, unremitting cholestatic jaundice soon followed. The patient's biliary status as monitored by serial liver biopsies demonstrated progression from chronic graft-versus-host disease to cirrhosis, culminating in death secondary to liver failure 25 mo after transplant.

Bone Marrow Transplantation↗
PubMed1990

Enzyme cytochemical localization of alkaline phosphatase in cultures of chondrocytes derived from normal and rachitic rats.

Epiphyseal growth plate cartilages were removed from rats which had been maintained on normal laboratory chow or a rachitogenic diet. Chondrocytes were released from the growth plates by collagenase digestion and cultured in tissue chamber slides. After 7, 10 and 12 days of culture, the chondrocytes were removed as intact multilayers and processed for electron microscopical enzyme cytochemical studies. Alkaline phosphatase activity in the cultures was visualized by means of a cerium based capture method. Electron-dense cerium phosphate deposits were localized on the membrane of matrix vesicles and plasma membranes of chondrocytes derived from normal and rachitic animals. The appearance of first crystals within matrix vesicles was characterized by a concomitant decrease in alkaline phosphatase activity in the membrane of these structures. Calcification was initiated at approximately the same time in cultures of chondrocytes derived from normal or rachitic animals. The results suggest that rickets has no serious effects on the capacity of chondrocytes to support matrix calcification in vitro. Additionally, the evidence indicates that alkaline phosphatase-positive matrix vesicles play a significant role in the initiation of this process.

Alkaline Phosphatase↗
PubMed1990

Impaired gastric acid secretion in mast cell-deficient mice.

Gastric acid secretion in normal (+/+) C57B1/6J mice and congeneic, mast cell-deficient (mi/mi) C57B1/6J mice was examined. The mast cell-deficient animals had approximately 50% of the normal quantity of gastric histamine and a blunted basal acid level and secretory response. These observations were noted despite the presence of parietal cells, which were normal in number and morphology. The H2-antagonist ranitidine inhibited basal acid secretion in both groups of animals. Exogenous histamine induced a significant secretory response in normal and mast cell-deficient groups, but only the secretory response in normal animals could be blocked by the H2-antagonist. Treatment of mast cell-deficient animals with histamine for seven consecutive days before stimulation did not restore the histamine response to the normal (+/+) levels. The normal animals demonstrated an acid secretory response to pentagastrin. Mast cell-deficient mice also responded to pentagastrin, but the response was less than that observed in the normal animals, and a significant difference was not evident in all experiments. Furthermore, simultaneous injection of mast cell-deficient animals with histamine and pentagastrin did not restore pentagastrin responsiveness to normal levels, although the histamine concentration used was sufficient to raise acid secretion to basal levels of normal mice. These results support the conclusion that non-mast cell histamine only partially contributes to basal gastric acid secretion and is insufficient to facilitate full parietal cell responsiveness. Furthermore, pentagastrin requires the presence of mast cells to elicit a maximal secretory response but can use non-mast cell histamine to activate the parietal cells for acid secretion.

Animals↗
PubMed1990

Matrix vesicle biogenesis in vitro by rachitic and normal rat chondrocytes.

Calcifying matrix vesicles (MVs) are released from chondrocytes and osteoblasts in monolayer culture. In the present studies, we tested the ability of rachitic versus normal rat growth plate chondrocytes in micromass or monolayer primary cultures to produce MVs. Unlike earlier reports of in vitro MV biogenesis by chicken chondrocytes in which most MVs were released into the medium, we found that most of the released rat matrix vesicles were entrapped in a newly formed cartilaginous matrix enveloping the cells. These matrix-associated MVs could be isolated by mild collagenase treatment and concentrated by differential centrifugation. Vesicle production slowed in the older 2- to 4-week-old cultures and, unlike vesicle release from cultured chicken chondrocytes, active vesicle production did not show a second burst of activity at 3 to 4 weeks. Alkaline phosphatase (ALP) activity diminished with time in culture in cells and matrix vesicles, suggesting a decrease in differentiative expression. Protein profiles on SDS polyacrylamide gels of native matrix vesicles and culture-derived MVs from rachitic and normal cells were quite similar and showed a typical simplified protein pattern as compared to chondrocyte plasma membrane proteins. There were distinctive proteins migrating at 130, 80 to 95, 66, 43, 20, and 14 kd. Culture-derived MVs showed vigorous in vitro calcifying activity that was ALP related. We conclude that 1) rachitic chondrocytes are essentially normal in their matrix vesicle production; 2) matrix entrapment of MVs is a characteristic of rat chondrocyte cultures; and 3) culture-produced MVs are similar to native MVs in protein profile and calcifiability, and thus can be studied as a model for normal MV composition and calcification.

Animals↗
PubMed1989

Guidelines for the clinical evaluation of hypersensitivity pneumonitis. Report of the Subcommittee on Hypersensitivity Pneumonitis.

In general, a history of exposure to "moldy" hay, birds, or other incriminated occupational or environmental inhalants in a patient with clinical and radiologic features consistent with HSP should lead to the demonstration of serum precipitins to the suspected antigen and an established diagnosis, confirmed by avoidance of the agent involved. Occasionally, other diagnostic procedures are required. The diagnosis is often difficult in domestic exposures, such as humidification and air conditioning systems. A careful environmental history is essential, and at times the physician must inspect the patient's environment personally. In most cases, the diagnosis is established if (1) the history and physical findings and pulmonary function tests indicate an interstitial lung disease, (2) the x-ray film is consistent, (3) there is exposure to a recognized cause, and (4) there is antibody to that antigen. In other exceptional circumstances, bronchoalveolar lavage may help. Biopsy is rarely needed. Special environmental studies and identification of new antigens require research facilities. Provocation tests are research procedures, not necessary for the diagnosis, and not needed in contested workmen's compensation adjudications.

Alveolitis, Extrinsic Allergic↗
PubMed1989

Regulation of Fc gamma 2a receptor-mediated phagocytosis by a murine macrophage-like cell line, P388D1: involvement of casein kinase II activity associated with Fc gamma 2a receptor.

A question of whether or not casein kinase II (CKII) activity associated with Fc gamma 2aR is involved in the regulation of phagocytic process mediated by this type of Fc gamma R was investigated. Our previous studies showed that the rate of phagocytosis of sheep erythrocytes (SRBC) coated with anti-SRBC antibody (EA) by P388D1 cells varies significantly depending on the isotypes of antibody and that Fc gamma 2aR isolated from the detergent lysate of P388D1 cells is associated with CKII activity, whereas Fc gamma 2bR is not. Fc gamma Rs-mediated phagocytosis is a major function of macrophages by which invading pathogens such as bacteria could be eliminated and therefore warrants the investigation of its biochemical mechanisms. We have recently shown that phagocytosis of EA2b mediated by Fc gamma 2bR of P388D1 cells as well as murine peritoneal macrophages could be up-regulated by promoting the association of various cytoskeletal components with the receptor by inhibiting Fc gamma 2bR-associated phospholipase A2 (PLA2). CKII activity-associated Fc gamma 2aR mediates phagocytosis of EA2a more effectively than PLA2-associated Fc gamma 2bR mediates phagocytosis of EA2b. We have therefore examined a potential role of CKII in Fc gamma 2aR-mediated phagocytosis by the use of a specific inhibitor of CKII activity (heparin). Results showed that heparin inhibited CKII activity associated with Fc gamma 2aR and effectively down-regulated the Fc gamma 2aR-mediated phagocytosis by apparently blocking the association of the receptor with four types of cytoskeletal components (actin-binding protein, myosin heavy chain, alpha tubulin, and actin).(ABSTRACT TRUNCATED AT 250 WORDS)

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1989

Modulation of macrophage superoxide-induced cytochrome c reduction by mast cells.

The effect of mast cells and mast cell granules on macrophage O2- release as determined by cytochrome c reduction was studied. In vitro activation of mast cells before macrophage activation caused a decrease in O2- -mediated cytochrome c reduction. This decrease was proportional to mast cell activation and reached 80% to 100% when mast cell mediator release was 40% to 50%. Incubation of isolated mast cell granules with macrophages before activation also inhibited O2- -mediated cytochrome c reduction in a dose-dependent manner. Mast cell granule-mediated inhibition of cytochrome c reduction was not caused by histamine, serotonin, or any other dialyzable components but was found to be caused by the scavenging of O2- by mast cell granule-bound superoxide dismutase. Macrophage uptake of sulfur 35-labeled mast cell granules, electron microscopic localization of mast cell granules in the macrophage phagosomes, and the abrogation of mast cell granule effect when the cells were preincubated at 0 degree C indicate that the effect was associated with the adherence or phagocytosis (or both) of mast cell granules. These results suggest that mast cell granules interact with macrophages and that granule superoxide dismutase scavenges O2- generated by the phagocytes.

Animals↗
PubMed1987

Effect of the mi allele on mast cells, basophils, natural killer cells, and osteoclasts in C57Bl/6J mice.

The osteopetrotic, microphthalmic (mi/mi) mouse lacks functional osteoclasts and has also been reported to be deficient in mast cells and natural-killer (NK) cells. The later deficiencies could be secondary to the osteopetrotic marrow, or a direct result of the mi allele. Therefore, heterozygotes were examined for these cell types, since these mice do not exhibit osteopetrosis. Adult +/mi animals have approximately 50%, and mi/mi animals examined by histologic techniques or tissue histamine levels have 0-10%, of the peritoneal, dermal, and intestinal mast cells compared with that of +/+ animals. Leukocyte histamine, indicative of the number of basophils, demonstrates the same pattern. Histamine content per mast cell in +/+ and +/mi animals is identical. The number of large granular lymphocytes (LGL) in splenic leukocyte preparations from +/mi animals is 50% that of +/+ animals, and these cells are undetectable in preparations from mi/mi mice. NK activity against YAC-1 cells paralleled the number of LGL present. The resorptive response of neonatal calvaria to parathyroid hormone was delayed in the case of cultured +/mi bone compared with that of +/+ bone, but the final rate of calcium release was identical. These data indicate that 1) the presence of one mi allele can affect the development of four distinct cell types, and 2) osteopetrosis alone does not account for the lack of mast cells, basophils, and NK cells in mi/mi mice.

Alleles↗
PubMed1986

Psoriatic arthritis affecting the manubriosternal joint.

Manubriosternal synovitis in the absence of peripheral arthritis or spondylitis, in a patient with pustular psoriasis, is described. The radiologic changes noted on lateral chest radiograph consisted of erosions, sclerosis, and joint space widening. This coincidence of manubriosternal joint arthritis and pustular psoriasis is unusual in western populations.

Adult↗
PubMed1985

Erosive arthropathy associated with scleromyxedema.

Mucin deposition in the skin (scleromyxedema) is a rare disorder with a historically confusing nomenclature. The etiology and pathogenesis of the disease is poorly understood. The precise extent of potential systemic involvement is uncertain but the prevailing hypothesis is that scleromyxedema is a disorder of skin fibroblasts without internal organ involvement. Two patients with scleromyxedema skin lesions are described in whom an erosive arthropathy developed in joints contiguous to clinically involved skin. Because of the absence of other causes of destructive arthritis, it is postulated that the associated skin disease resulted in infiltration of adjacent synovium with subsequent erosions.

Aged↗
PubMed1983

Effect of location, pH, and temperature of instillate in bronchoalveolar lavage in normal volunteers.

Bronchoalveolar lavage has not been subjected to careful standardization. We examined the variables of lung lavage location and lavage fluid composition (pH and temperature) upon the percent of fluid recovered, cell count and differential, protein and pH in normal subjects. In the first part of the study, random order lavages of the right middle lobe (RML), right lower lobe (RLL), left lingula, and left lower lobe (LLL) were performed with 100-ml aliquots of normal saline (pH, 5.5) at room temperature (25 degrees C). Percent fluid recovery was greater in the RML and lingula than in the RLL (p less than 0.05). Cell count, cell differential, and protein were similar between lobes. In the second part of the study, each lobe was lavaged with 50-ml aliquots: the RML with normal saline at 37 degrees C, the RLL with normal saline buffered to a pH of 7.0 at 37 degrees C, the left lingula with normal saline at 25 degrees C, and the LLL with normal saline buffered to a pH of 7.0 at 25 degrees C. Percent fluid recovery was greater in the RML than in the lingula and greater in both the RML and lingula than in the lower lobes (p less than 0.05). Total cell count was significantly higher in the RML than in the LLL (p less than 0.05). Cell count per milliliter and protein recovered were not different between any lobe lavaged. The pH of recovered fluid was greater with buffered saline. Complications of fever and chills occurred in almost 50% of subjects in both parts of the study. Lavage location can affect fluid recovery. Alteration of lavage fluid composition did not affect cell or protein recovery. We suggest lavage of the RML to ensure larger fluid recovery and the highest total cell count.

Adult↗