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Biomedical subjects

E Stein

Publications and source records attributed to E Stein.

At least 109 records · Page 6Linked to original sources
PubMed1989

Fetal pancreas transplantation in miniature swine. II. Survival of fetal pig pancreas allografts cultured at room temperature.

Islet-allograft survival has been shown to be markedly prolonged in rodents when donor tissue has been precultured at 24 degrees C. In this study, the feasibility of this approach was tested in NIH minipigs transplanted with fetal pancreases. Collagenase-digested fetal pig pancreatic tissues survived in culture at 24 degrees C for 6-7 days and continued to grow in vitro at 37 degrees C after being transferred. These tissues no longer stimulated allogeneic lymphocytes in vitro, although some tissues cultured at 37 degrees C did. This allogeneic stimulation did not correlate to the number of major histocompatibility complex (MHC) class II-positive cells in stimulator pancreatic cultures. When transplanted into an omentum pouch of normal, nonimmunosuppressed minipigs, fresh fetal pancreatic tissues were rejected within 14 days. Tissues cultured at 24 degrees C grew, and beta-cells proliferated in minipigs treated daily with cyclosporin A (CsA) and azathioprine. Twelve normal minipigs were transplanted with 24 degrees C-cultured fetal pancreases: 8 pigs received no treatment, 2 received 14 mg.kg-1.day-1 CsA for 14 days, and 2 received 6-7 intravenous injections of platelets prepared from pooled farm-pig blood before grafting. Strong lymphocytic infiltration was detected in all grafts removed between 30 and 90 days posttransplantation. However, beta-cells were found on day 45 in one of five minipig pancreas grafts incompatible at the MHC loci and on days 60-90 in all three grafts compatible at MHC but incompatible at minor histocompatibility loci. Short-term CsA treatment did not prolong survival of allografts from farm pigs into minipigs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Platelet-generated thromboxane A2 enhances norepinephrine release from adrenergic nerves.

Platelet-generated thromboxane A2 enhances norepinephrine release from adrenergic nerves. Microsomes were prepared from outdated human platelets and incubated with arachidonic acid to produce thromboxane A2. The incubate was added to isolated, electrically stimulated rabbit portal veins to determine its effect on adrenergic neurotransmission. Immunoreactive thromboxane B2 concentrations were measured to assess the generation of the precursor, thromboxane A2. Addition of microsomes in the presence of arachidonic acid (1 microM) caused a concentration-dependent increase in thromboxane B2 concentrations, electrically induced force and norepinephrine release. Inclusion of acetylsalicylic acid (10 microM) or the thromboxane synthase inhibitor, U63557A (100 micrograms/ml), in the arachidonic acid-microsome incubate eliminated the potentiation of force, norepinephrine release and thromboxane B2 generation. The thromboxane receptor antagonist, SQ30741 (1 microM), also eliminated the microsome effects on neurogenic force and norepinephrine release but not on thromboxane generation. The microsome-arachidonic acid incubate did not influence norepinephrine concentration-contractile response curves. These data are consistent with a potentiative action of thromboxane A2 on adrenergic neurotransmission, primarily mediated by enhanced release of norepinephrine. The physiological or pathological significance of this observation depends on the thromboxane concentrations in the vicinity of adrenergic nerves.

Animals↗
PubMed1987

Experimental studies on the disappearance of subretinal fluid after episcleral buckling procedures without drainage.

We have developed an experimental model to show that an additional mechanism apart from absorption by pigment epithelium is responsible for the absorption of subretinal fluid. The cause of a fast diminution of subretinal fluid after a buckling procedure is the prominence of the buckle as an obstacle to fluid movements in the eye. This results in any fluid being pushed through the retinal hole into the vitreous. When the retinal hole is closed by the buckle, the remaining part of the subretinal fluid is slowly absorbed by the pigment epithelium present. We performed a preliminary qualitative and quantitative analysis of the phenomena occurring using the finite element method of Zienkiewicz.

Absorption↗
PubMed1987

Alpha adrenergic receptors mediate angiotensin-induced prostaglandin production in the rabbit isolated vas deferens.

The effect of alpha adrenergic receptor antagonists on concentration-dependent response to angiotensins II and III was examined in the electrically stimulated isolated rabbit vas deferens. The force generated by a nonadrenergic neural mechanism was reduced by both peptides whereas the force generated by adrenergic neural mechanisms was enhanced. Angiotensin III-induced inhibition of the nonadrenergic contraction was significantly greater than that of angiotensin II for all groups. Yohimbine (1 X 10(-4) M), an alpha-2 receptor antagonist, attenuated the depression of the nonadrenergic contraction produced by angiotensins II and III. Yohimbine (1 X 10(-5) and 1 X 10(-4) M) also significantly reduced angiotensin II-induced prostaglandin E (PGE) synthesis. Yohimbine only significantly altered the angiotensin III-induced PGE synthesis at an antagonist concentration of 1 X 10(-4) M. Rauwolscine (1 X 10(-8) and 1 X 10(-7) M) attenuated angiotensin II-induced PGE production and at a higher concentration (1 X 10(-6) M) reduced angiotensin III-induced PGE production. The alpha-1 antagonist, prazosin (1 X 10(-6) M), did not alter nonadrenergic contractile or PGE responses to either angiotensin. The alpha-2 agonist, clonidine, both inhibited the nonadrenergic neural contraction and enhanced PGE synthesis. We interpret these data to indicate that angiotensins II and III may act via separate mechanisms to induce PGE synthesis in the vas deferens, with angiotensin II effects being more dependent on norepinephrine release from adrenergic nerves.

Angiotensin II↗
PubMed1984

Tooth transplantation with the periodontium intact: a histometric analysis.

A method was devised, from a pilot study, for transplanting a root-treated tooth with an intact periodontium into a newly prepared socket to assess whether the prognosis for transplantation procedures could be improved. Five male vervet monkeys were used for the definitive study. The mandibular central incisors were extracted from each monkey and the sockets were allowed to heal for 5 weeks. Thereafter a window of gingiva overlying each of these healed receptor sites was removed and the sockets were prepared with tapered burs. The distal root of the mandibular second molar was used as the transplant tooth and the distal root of the first molar as the control tooth. The transplant tooth was removed, together with surrounding alveolar bone which was then trimmed to a thickness of approximately 1 mm. The control tooth was extracted with root forceps. After transplantation, the teeth were splinted to the adjacent incisors for 3 weeks. After 8 weeks the healing process was examined histologically, both qualitatively and quantitatively. Replacement resorption (ankylosis) was not observed. Student's t test for paired samples revealed that the incidence of secondary cementum formation was significantly greater on the control teeth. The minimization of trauma may be the reason ankylosis did not occur.

Alveolar Process↗
PubMed1984

Changes in fatty acids in phospholipids of the bronchoalveolar fluid in bacterial pneumonia and in adult respiratory distress syndrome.

Fatty acids of the phospholipid fraction of bronchoalveolar lavage fluid from patients with bacterial pneumonia or with the adult respiratory distress syndrome were chromatographed and the patterns compared with those for a control group. In the control group, palmitic acid (16:0) was the predominant fatty acid, accounting for 58.0% (SD 8.25%) of the total fatty acid, a proportion significantly higher (p less than 0.001) than in the distress-syndrome group (42.1%, SD 4.88%) or the acute pneumonia group (32.1%, SD 1.73%). There was a greater proportion of oleic acid (18:1) in the disease groups; thus the ratio of palmitic to oleic acid was useful in distinguishing these three groups. No patient with a palmitic/oleic acid ratio greater than 2.45 had evidence of parenchymal inflammation. Of those with a ratio less than 1.3, 89% had acute bacterial pneumonia.

Adolescent↗
PubMed1983

Portacaval shunt in patients with familial hypercholesterolemia.

Portacaval shunt was performed in ten patients with homozygous and two with heterozygous familial hypercholesterolemia (FH). Total serum cholesterol was lowered by 20% to 55.4% during follow-up periods of 14 months to almost 9 years, with commensurate decreases in LDL cholesterol. The effect on HDL cholesterol and triglyceride levels was variable. Tendinocutaneous xanthomas diminished or disappeared. Growth and development in children proceeded or accelerated. There was no detectable emotional or intellectual deterioration. Hepatic failure did not occur, although blood ammonia concentrations and serum alkaline phosphatase levels increased relative to preoperative values. Cardiac symptoms were often improved, but evidence of reversal of cardiovascular lesions was inconclusive. Three patients with pre-existing heart disease died of cardiac complications after 4 months, 18 1/2 months, and 30 months. Portacaval shunt has been effective therapy for patients with FH who were refractory or intolerant to medical treatment; it should be performed before the development of irreversible cardiovascular damage.

Adolescent↗
PubMed1982

[Crohn syndrome].

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Crohn Disease↗
PubMed1982

[Contact eczema].

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Dermatitis, Contact↗