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T Kirsch

Publications and source records attributed to T Kirsch.

At least 73 records · Page 4Linked to original sources
PubMed1991

Ca2+ binding properties of type X collagen.

Type X collagen is a developmentally regulated collagen that is only synthesized by chondrocytes of the hypertrophic and calcifying zone in fetal cartilage. There is evidence in the literature that type X collagen may be involved in cartilage calcification. Here we show that type X collagen synthesis precedes calcium deposition in nodules of fetal human chondrocytes forming in cell culture and present evidence that type X collagen binds calcium in a specific and dose dependent manner. In an assay using bovine type X collagen coupled to beads and 45Ca2+ we determined a total of about 15 binding sites per alpha 1(X) chain with a dissociation of 32 microM.

Animals↗
PubMed1991

Isolation of human type X collagen and immunolocalization in fetal human cartilage.

Type X collagen was extracted with 1 M NaCl and 10 mM dithiothreitol at neutral pH from fetal human growth plate cartilage and purified to homogeneity by gel filtration and anion-exchange chromatography. The purified protein migrates in SDS/polyacrylamide gels with an apparent Mr of 66,000 under reducing conditions, and as a high-Mr oligomer under non-reducing conditions. Purified collagenase digests most of the molecule; pepsin digestion at 4 degrees C decreases the Mr of the monomer to 53,000. A rabbit antiserum was raised against purified human type X collagen; the IgG fraction was specific for this collagen by criteria of ELISA and immunoblotting after absorption with collagen types I, II, VI, IX and XI. Immunohistological studies localized type X collagen exclusively in the zone of hypertrophic and calcifying cartilage.

Amino Acids↗
PubMed1991

Protective and restorative role of AS101 in combination with chemotherapy.

The immunomodulator AS101 has been found previously by us to stimulate the secretion of high levels of interleukin 1 and colony stimulating factor (CSF) in vitro, as well as the production of CSF in vivo in mice models. These cytokines are known to induce proliferation and differentiation of hematopoietic progenitor cells from the spleen and bone marrow (BM) and to protect mice from DNA-damaging agents. The present studies were designed to evaluate the effects of prolonged treatment with AS101 on myelopoiesis, BM cellularity, and CSF secretion in mice treated with a sublethal dose of cyclophosphamide (CYP) and on the survival of mice undergoing treatment with lethal doses of this compound. In this model, the hematopoietic progenitors were suppressed during the overbound phase of myelopoiesis resulting from the cytotoxic effects of CYP. This allowed the detection of a significant proliferative effect of AS101 in vivo on BM colony-forming units granulocyte-macrophage progenitor cells, BM cellularity, and the secretion of CSF. Moreover, AS101 protected these animals from the lethal effects of high doses of CYP. These protective effects were demonstrable only when AS101 was administered to mice prior to CYP treatment. The only exception was CSF secretion by spleen cells that had been reconstituted when AS101 was administered both prior to and following CYP treatment. AS101 was found to have a synergistic effect with CYP in the treatment of tumor-bearing mice, suggesting that the combination of these two modalities provides a more effective treatment of their tumors. These results strongly suggest an immunoregulatory role for AS101 in counteracting the chemotherapy-induced hematopoietic suppression as well as usefulness as adjunct treatment of cancer when used in combination with CYP.

Adjuvants, Immunologic↗
PubMed1991

An analysis of emergency department use by patients with minor illness.

STUDY OBJECTIVE: To describe the motivation for emergency department use by patients with minor illnesses and compare the demographics and social class characteristics of these patients with those of the general ED population. DESIGN: Observational, case-control study. SETTING: Urban ED. TYPE OF PARTICIPANTS: A sample group of 325 adult, nongeriatric patients with minor illnesses was selected by screening all patients registering in the ED between 9:00 AM and 6:00 PM on 15 randomly selected weekdays. A patient was included in this study group if the chief complaint, method of arrival, and subsequent evaluation met predetermined criteria for minor illness. A comparison group (control) was composed of all ED patients (224) who presented during two randomly selected 24-hour periods that did not overlap with the times of study group enrollment. INTERVENTIONS: Sample group patients were interviewed concerning their socioeconomic backgrounds, reasons for using the ED, and perceptions of the urgency of their conditions. Comparison group patients' interviews were confined to the collection of demographic and socioeconomic information. MEASUREMENTS AND MAIN RESULTS: There were more men (P = .12), more self-pay patients (P = .017), and fewer Medicare patients (P less than .001) in the study group. There also was a strong trend toward higher income (P = .059) in the study group. The racial, marital, employment, and educational backgrounds of the two groups were similar. Eighty-two percent of the study group had no chronic illness, and only 36% reported a problem of more than three days' duration. Patients chose to use the ED because of its convenience (23.7%), the absence of previous provider relationships (22.1%), and the inability to make a prompt appointment with their regular provider (19.0%). Major differences existed between the reasons for which different demographic and socioeconomic groups chose ED care. Study group patients believed that less than 24 hours should elapse between the onset of their problem and the time at which they receive medical care. CONCLUSION: There are no major differences in ED use for minor illness patients from different racial, educational, and economic backgrounds. These patients tend to have a low frequency of chronic illness and often have no established health care provider. They choose the ED for its ease of access and the wide scope of care that can be delivered.

Adult↗
PubMed1990

Isolation of bovine type X collagen and immunolocalization in growth-plate cartilage.

Type X collagen was extracted with 1 M-NaCl and 10 mM-dithiothreitol at neutral pH from fetal-bovine growth cartilage and purified to homogeneity by using f.p.l.c. gel filtration on a Superose 12 column, followed by ion-exchange chromatography on a Mono Q column. The purified protein migrates in SDS/polyacrylamide gels with an apparent Mr of 58,000 under reducing conditions and as a high-Mr oligomer in its unreduced form. The amino acid composition is similar to the published composition of chick type X collagen. Pepsin digestion at 4 degrees C decreases the Mr of the monomer to 43,000; purified bacterial collagenase digests most of the molecule, leaving a non-collagenous domain of apparent Mr 15,000, which probably represents the C-terminal globular domain. The IgG fraction from a rabbit antiserum raised against purified bovine type X collagen was specific for this collagen by the criteria of e.l.i.s.a. and immunoblotting after immunoabsorption with collagen types I, II, IX and XI. Immunofluorescence localization of type X collagen in sections of fetal-bovine and human cartilage was possible after acetone fixation of sections and hyaluronidase treatment. Type X collagen was restricted to the zone of hypertrophic and calcified cartilage inside the bone spicules of the growth plate.

Amino Acids↗
PubMed1988

Ball Memorial Hospital: Section 2 Sherman Act analysis in the alternative health care delivery market.

In 1986, the Seventh Circuit Court of Appeals in Ball Memorial Hospital v. Mutual Hospital Insurance denied an injunction sought under the antitrust laws by the plaintiffs, eighty acute care hospitals, which would have precluded Blue Cross and Blue Shield of Indiana from implementing a Preferred Provider Organization. The Ball court used a conservative economic analysis to deny the injunction and failed to consider many industry-specific factors. This Note examines these factors and challenges the Ball court's position by arguing that antitrust scrutiny of alternative health care delivery markets must go beyond the court's narrow approach.

Blue Cross Blue Shield Insurance Plans↗
PubMed1986

Plant acyl-CoA oxidase. Purification, characterization, and monomeric apoprotein.

Purified glyoxysomes from cotyledons of germinating cucumber seedlings were used as a source to separate matrix enzymes of the organelle by hydrophobic chromatography. Glyoxysomal acyl-CoA oxidase eluted from the column like hydrophobic proteins and exhibited an Mr of 150,000. An oxidase with identical properties could be prepared in large quantities by a purification procedure starting with crude extracts from cotyledons of 4-day-old etiolated seedlings. The purification procedure included chromatography on phenyl-Sepharose and hydroxylapatite and molecular sieving. 1500-fold purification led to an enzyme of apparent homogeneity characterized by a specific activity of 27 units/mg of protein. Plant acyl-CoA oxidase is a homodimer with a subunit of Mr 72,000. Monospecific antibodies raised in rabbits were used to reveal dissimilarity to the fungal oxidase. The plant enzyme also differed markedly in molecular structure and amino acid composition from the liver peroxisomal enzyme. Glyoxysomal acyl-CoA oxidase acts selectively on fatty acyl-CoAs with 16 or 18 C atoms, cis-9-unsaturated esters with a C16 or C18 acyl moiety being converted with higher rates than saturated or polyunsaturated fatty acyl-CoAs. Besides the enzymatically active organellar form of acyl-CoA oxidase, the monomeric apoprotein was detected when short-term labeling of cotyledons in vivo was performed. The apoprotein (immunoprecipitable by antibodies raised against the glyoxysomal enzyme) did not differ in size from the subunit of the glyoxysomal dimeric enzyme.

Acyl Coenzyme A↗
PubMed1978

Pharmacologic profile of methyl 2-tetradecylglycidate (McN-3716)--an orally effective hypoglycemic agent.

A specific inhibitor of fatty acid oxidation, methyl 2-tetradecylglycidate (McN-3716) has been found to produce a dose dependent hypoglycemic effect when administered orally to rats, mice, and dogs. In addition to being more potent than other inhibitors of fatty acid oxidation, McN-3716 was also found to be 15--20 times more potent than tolbutamide in lowering the blood glucose of fasting rats. Furthermore, evidence is presented that McN-3716 produces hypoglycemia by a mechanism which differs from that of other oral hypoglycemic agents, the biguanides and the sulfonylureas. As predicted by the Randle glucose-fatty acid cycle, McN-3716 lowered glucose concentrations only under conditions where fatty acids were being used as the major energy substrates (fasting, diabetes, and feeding of high fat diets) but not under conditions where energy was derived mainly from carbohydrate (fed state or following hypophysectomy). Administration of McN-3716 produced a remarkable lowering of the plasma glucose and the glycosuria of depancreatized dogs but did not result in complete normalization of glucose, especially the excursions of blood glucose following feeding. It did, however, produce virtually complete reversal of the ketoacidosis of alloxan diabetic rats and depancreatized dogs without worsening the plasma lipid profile. Thus, McN-3716 may have potential utility as an oral therapeutic agent for the treatment of ketosis-prone juvenile or maturity-onset diabetes.

Animals↗
PubMed1978

A pharmacologic profile of McN-3495 [N-(1-methyl-2-pyrrolidinylidene)-N'-phenyl-1-pyrrolidinecarboximidamide], a new, orally effective hypoglycemic agent.

McN-3495, a new compound unrelated strucuturally to the sulfonylureas or phenformin, has been found to produce a hypoglycemic effect in nondiabetic rats, dogs, mice, and monkeys. The minimum effective dose of McN-3495 that lowers fasting blood glucose and improves glucose tolerance was found to be about 2.5 to 5 mg-per kilogram, per os, except in fasted monkeys, in which a tenfold greater potency was observed. When McN-3495 was given repeatedly for three to five days, no tolerance to the hypoglycemic activity occurred and no changes in other biochemical parameters were observed. In addition to being three to four times more potent than tolbutamide, McN-3495 also differs from the sulfonylureas in lowering blood glucose concentrations of streptozotocin-diabetic rats and db/db mice, and, moreover, oral administration to normal fasted dogs did not produce the characteristic rise in insulin concentrations observed with tolbutamide. Furthermore, unlike the biguanides, McN-3495 can lower dog and rat fasting blood glucose concentrations and can improve glucose tolerance whether the glucose is administered orally or parenterally. However, McN-3495, as phenformin, fails to work in totally depancreatized dogs.

Animals↗