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Biomedical subjects

J B Weiss

Publications and source records attributed to J B Weiss.

At least 109 records · Page 6Linked to original sources

1 Alpha 2 alpha 3 alpha collagen is arthritogenic.

Native 1 alpha 2 alpha 3 alpha collagen (500 micrograms per rat) was both immunogenic and arthritogenic in Alderley Park rats (46% developed arthritis) but only immunogenic in Sprague-Dawley rats. Conversely, native type II collagen (500 micrograms per rat) was immunogenic and arthritogenic in both strains (64% arthritic in Alderley Park strain, 57% arthritic in Sprague-Dawley strain). The inflammatory polyarthritis induced by 1 alpha 2 alpha 3 alpha collagen was similar to that produced by native type II collagen in clinical appearance, time of onset, and histology. Antibodies raised to native bovine type II collagen cross-reacted with native 1 alpha 2 alpha 3 alpha collagen and vice versa. Thus the minor collagen component of cartilage, the 1 alpha 2 alpha 3 alpha collagen, as well as the major collagen component, type II collagen, are immunogenic and arthritogenic in the rat, with strain differences.

Animals↗

Gluten-sensitive enteropathy. Immunoglobulin G heavy-chain (Gm) allotypes and the immune response to wheat gliadin.

Anti-gliadin antibody was measured by radioimmunoassay in 30 Caucasians with gluten-sensitive enteropathy (GSE). 22 GSE patients maintained on a gluten-free diet for 1.5 to 20 yr (mean duration 76 mo) had elevated serum concentrations of IgG antigliadin antibody. Among GSE patients on a gluten-free diet, antigliadin antibody was seen only in those having the chromosome 14-encoded IgG immunoglobulin heavy chain allotype marker G2m(n). IgG antigliadin antibody was found in GSE patients with G2m(n) regardless of whether the HLA-B8 and/or -DR3 major histocompatibility complex antigens that occur frequently in GSE were present. No patient lacking G2m(n) had significant levels of antigliadin antibody. The association between antigliadin antibody and the immunoglobulin heavy chain allotype marker G2m(n) in GSE patients likely reflects the presence of Gmn-linked variable region genes or Gmn-linked genes that regulate variable region gene expression.

Adolescent↗

Separation of two bone cell populations from fetal rat calvaria and a study of their responses to parathyroid hormone and calcitonin.

Bone cells released from perinatal rat calvaria by digestion with clostridial peptidase were separated into two distinct populations (designated types B and C) by equilibrium density centrifugation on a two-step gradient of Percoll. They were extensively characterized by light and electron microscopy and for behaviour in culture, acid and alkaline phosphatase activity, collagen synthesis, collagenase secretion and adenylate cyclase response to parathyroid hormone (PTH) and calcitonin. Type C cells were predominantly large with up to seven nuclei and an unusual cytoplasmic appearance in cytocentrifuge preparations. They did not proliferate in culture and we have established culture conditions which prevented their overgrowth by contaminating proliferative cells. In culture these cells had low alkaline and high acid phosphatase and high aryl sulphatase activity, and synthesized little collagen. In contrast type B cells were mostly smaller and many had irregular cytoplasmic projections. In culture they became polygonal in shape, proliferated rapidly, and reached confluence in 4-5 days. These were low in aryl sulphatase and acid phosphatase, high in alkaline phosphatase activity, and synthesized labelled collagen actively with [3H]proline and ascorbic acid included in the culture medium. The two cell population were found to differ in culture in two important further respects. First, the type C cells showed an adenylate cyclase response to calcitonin but not to PTH, while the converse was true for type B cells; this was so over at least a 20-fold range of isobutylmethyl xanthine concentration. Secondly, type C cells in culture secreted an active collagenolytic enzyme. Type B cells secreted much lower levels of a predominantly latent collagenase which required activation by mersalyl. Co-culture of type C and type B cells led to a marked reduction in the content of active collagenase in the culture medium.

Animals↗

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Depth Perception↗

Comparison of the maternal and neonatal effects of halothane, enflurane, and isoflurane for cesarean delivery.

The maternal and neonatal effects of 50% O2-50% N2O alone and 50% O2-50% N2O combined with 0.5% halothane, 1.0% enflurane, or 0.75% isoflurane were studied in 42 healthy parturients undergoing general anesthesia for elective primary or repeat cesarean delivery at term. All patients received thiopental and succinylcholine for induction and were intubated and ventilated with a tidal volume of 10 ml/kg at a rate of 10 breaths/min. Two of 12 (17%) patients given O2-N2O alone had recall; none who received a potent inhalation agent had any recall. Blood loss was similar in all four groups. There were no significant differences between groups in induction-to-delivery and uterine incision-to-delivery intervals, the frequency of Apgar scores less than 7 at 1 and 5 min, maternal and fetal blood-gas tensions, acid-base balance, lactate values, and early neonatal neurobehavioral scores at 2-4 h. It is concluded that analgesic concentrations of halothane, enflurane, and isoflurane can be safely added to 50% O2-50% N2O to prevent maternal awareness during general anesthesia for cesarean delivery while maintaining normal maternal and neonatal conditions.

Anesthesia, Inhalation↗

Isolation and native characterization of cysteine-rich collagens from bovine placental tissues and uterus and their relationship to types IV and V collagens.

A simplified procedure for the fractionation and purification of different collagen types from various tissues is described which is particularly efficient in separating type-V from type-IV collagen, and high-mol.-wt. (HMW) aggregates from 7 S collagen. Uterus and maternal villi contain 2 forms of type-V collagen - [alpha 1(V)]2 alpha 2(V) and [alpha 1(V) alpha 2(V) alpha 3(V) - which have been separated on DEAE-cellulose. Uterus however appears to be the richest source of both HMW aggregates and the [alpha 1(V) alpha 2(V) alpha 3(V)] collagen, and a probable relationship between these collagens is discussed.

Amino Acids↗

Spinal anaesthesia for Caesarean section. The influence of hypotension on neonatal outcome.

The effect upon the neonate of a short period of maternal hypotension sustained during the initiation of spinal analgesia for Caesarean section was studied. Babies born to mothers with hypotension were significantly more acidotic than controls although acid-base levels were still within normal limits. Neurobehavioural studies were found to be normal in both groups at 4 and 24 hours. It was concluded that a short period (less than 2 minutes) of hypotension was not harmful to the neonate.

Acid-Base Equilibrium↗

A low-molecular-weight angiogenic factor in cat retina.

A low-molecular-weight angiogenic factor has been isolated from healthy adult cat retinas. The factor, which has been purified by diethylaminoethyl (DEAE) cellulose chromatography and affinity chromatography, stimulates neovascularisation of the chick chorioallantoic membrane and has a number of properties similar to those previously described for a tumour factor. The finding of an angiogenic factor in healthy retina and its relationship to previously described inhibitors of angiogenesis is discussed.

Angiogenesis Inducing Agents↗

[Hemodynamic effects of the association of nifedipine and acebutolol].

The aim of this study was to assess the effects of the association of sublingual nifedipine and intravenous acebutolol on left ventricular inotropism. A series of 30 randomised patients underwent hemodynamic investigation repeated after a 30 minute interval comprising measurement of left ventricular (LVP) and aortic (AoP) pressures and ventriculography (Vo). Between the two Vo, Group I (N = 10) were given 20 mg sublingual nifedipine (N), Group II (N = 0) were given I mg/Kg acebutolol (A) intravenously in 5 minutes, and Group III (N = 10) the association of 20 mg sublingual N and I mg/Kg intravenous A. All patients had normal resting left ventricular function (ejection fraction greater than 0,55). In Group I, a significant improvement in left ventricular function with reduction of end diastolic pressure, increase ejection fraction, VCF and cardiac index was observed. THese changes were secondary to the reduction in aortic impedence with no effects on the contractile element (assessed by end systolic pressure/end systolic volume - ESP/ESV - ratio). In Group II, a significant reduction in these indices of left ventricular function was recorded secondary to a reduction in contractility. Group III had a special hemodynamic profile comprising: a reduction in afterload identical to that observed in Group I; a significantly greater reduction in the ESP/ESV ratio than in Group II; a greater reduction in the indices of left ventricular function (especially EF, VCF and CI) than in Group II, but the difference was not significant. The data obtained under the conditions of this acute hemodynamic investigation in patients with normal basal left ventricular function may be summarised thus: 1) Nifedipine alone has no detectable negative inotropic effects. 2) The association with acebutolol, nifedipine seems to potentiate myocardial depression (ESP/ESV). 3) This therapeutic association, the value of which has already been demonstrated in coronary insufficiency should be used carefully without precise knowledge of the left ventricular function.

Acebutolol↗

Treatment of hemorrhagic gastritis with 15(R)-15 methyl prostaglandin E2: report of a case.

A 19-yr-old male developed severe hemorrhagic gastritis following three abdominal operations. Treatment with intravenous cimetidine and hourly antacids to maintain his gastric pH above 5 failed to affect gastrointestinal bleeding. Also, peripheral venous vasopressin, propantheline bromide, and glucagon were without effect. Total gastrectomy was considered to control his bleeding. However, since a number of prostaglandin analogs prevent gastric lesions produced by many noxious agents (e.g., aspirin, alcohol, strong acid or alkali, etc.) in animals and humans, the patient was treated with 50 micrograms of 15(R)-15 methyl prostaglandin E2 intragastrically every 6 h for 10 days. To epimerize the 15(R) form to the more active 15(S) form, 50-100 ml of 50-mN HCl was placed into the patient's stomach immediately before each dose. Bleeding ceased within 24 h of the onset of 15(R)-15 methyl prostaglandin E2 therapy and did not recur. The prompt response to 15(R)-15 methyl prostaglandin E2 in combination with hourly antacids in this patient with persistent and severe hemorrhagic gastritis suggests a therapeutic effect and the need for a prospective double-blind clinical trial.

Abdomen↗