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Biomedical subjects

G Leibowitz

Publications and source records attributed to G Leibowitz.

34 records · Page 2Linked to original sources
PubMed1995

Hyperinsulinemic hypoglycemia of infancy (nesidioblastosis) in clinical remission: high incidence of diabetes mellitus and persistent beta-cell dysfunction at long-term follow-up.

In persistent hyperinsulinemic hypoglycemia of infancy (PHHI), the long term outcome of the disease is not well documented. Previous reports suggested that partial pancreatectomy in infants does not endanger future islet function. We evaluated endocrine pancreatic function in 14 PHHI patients 6.5-21 yr after diagnosis. Eight underwent early subtotal pancreatectomy, and 6 were medically treated; all were in clinical remission. Intravenous glucose tolerance and C-peptide suppression tests were performed, with multiple determinations of hormone levels. The insulin response to glucose was blunted in all pancreatectomized and in 2 conservatively treated patients. Glucose disposal was reduced in 6 pancreatectomized patients and in 2 medically treated subjects. Six of the pancreatectomized patients, including two with normal glucose disposal at first evaluation, developed overt diabetes during puberty. None in the medically treated group became diabetic; however, only 2 patients have reached puberty. C-Peptide suppression in response to hypoglycemia was inadequate in 4 of 5 pancreatectomized and 3 of 5 nonpancreatectomized patients studied. These results show that children with PHHI have impaired insulin responses to glucose and lack of suppressibility of endogenous insulin secretion several years after clinical remission. Thus, the beta-cell defect responsible for the disease in infancy is not corrected with time despite the disappearance of spontaneous hypoglycemia. Insulin secretion seems more disturbed in pancreatectomized patients; the majority develop insulin-requiring diabetes during puberty. An effort should be made to treat PHHI patients medically to avoid pancreatectomy; this may reduce the incidence of diabetes at puberty.

Adolescent↗
PubMed1994

[Glucose phosphate isomerase deficiency with congenital nonspherocytic hemolytic anemia].

Glucose phosphate isomerase (GPI) deficiency is an unusual cause of hereditary nonspherocytic hemolytic anemia described in Israel in 2 families of Arab ancestry. The disease, inherited as an autosomal recessive disorder, manifests itself by symptoms and signs of chronic hemolysis which are often ameliorated by splenectomy. A variety of defective GPI variants, characterized by modified physicochemical and/or kinetic properties of the enzyme have been reported, suggesting extensive polymorphism for this enzyme deficiency. We recently diagnosed GPI deficiency in a 23-year-old Jewish Ashkenazi man. Since the age of 1 year, when a diagnosis of hemolytic anemia of undetermined etiology was made, he has required frequent blood transfusion. Since splenectomy, performed when he was 6 years old, the requirement for blood transfusions diminished drastically, restricted to hemolytic crises following intercurrent febrile illnesses. To the best of our knowledge, this is the first report of GPI deficiency in an Israeli family of Ashkenazi-Russian origin.

Adult↗
PubMed1994

Dermatomyositis associated with Crohn's disease.

A 29-year-old woman with quiescent Crohn's disease developed severe myositis. Serum creatine phosphokinase was markedly elevated, and muscle biopsy showed typical findings of dermatomyositis. The muscular symptoms promptly responded to combined treatment with corticosteroids and azathioprine. The association between inflammatory bowel disease and inflammatory myopathies is very rare. We review the clinical, pathological, and pathophysiological aspects of this association.

Adult↗
PubMed1994

Improvement of sleep apnoea due to acromegaly during short-term treatment with octreotide.

Two acromegalic patients suffering from severe obstructive sleep apnoea syndrome were treated with the long-acting somatostatin analogue octreotide. Daytime sleepiness and fatigue improved within a few days. Repeat sleep studies performed after octreotide treatment revealed more confluent sleep with a shorter duration of sleep apnoea. Nocturnal hypoxaemia improved in one patient. Octreotide might be an effective noninvasive treatment for sleep apnoea of acromegaly.

Acromegaly↗
PubMed1994

Hyperproinsulinemia and insulin deficiency in the diabetic Psammomys obesus.

Patients with noninsulin-dependent diabetes mellitus exhibit increased proportions of plasma proinsulin and proinsulin conversion intermediates. We used hyperinsulinemic diabetic and nondiabetic Psammomys obesus to study the possible relationship between steady state pancreatic insulin stores and the proportion of proinsulin-related peptides in the plasma and pancreas. Insulin-like peptides were separated by reverse phase HPLC and identified by pulse-chase experiments. A marked increase in the proportions of proinsulin and proinsulin conversion intermediates in the plasma and pancreas of diabetic nonfasted Psammomys was associated with 90% reduction in insulin stores of the pancreas. After a 16- to 20-h fast, the depletion of pancreatic insulin in the diabetic animals was partially corrected, and the proinsulin/insulin ratio was normalized. In contrast, nondiabetic Psammomys showed only 50% reduction in pancreatic insulin stores under nonfasting conditions, with no change in the proinsulin/insulin ratio. These findings suggest that in the diabetic Psammomys obesus, the pancreatic capacity for storage of insulin may be limited; the metabolic consequences of this limitation are amplified by increased secretory demand secondary to insulin resistance, thus facilitating the establishment of hyperglycemia, which may in itself further exacerbate pancreatic dysfunction.

Animals↗
PubMed1993

A unique presentation of lymphoma of the colon.

Non-Hodgkin's lymphoma often involves the gastrointestinal tract, but primary lymphoma of the colon is rare. Primary lymphoma of the colon masquerading as inflammatory bowel disease is even rarer. We report a patient with an initial diagnosis of Crohn's colitis, who later appeared to have had non-Hodgkin's lymphoma of the colon. We review the diagnosis and treatment of this rare disease.

Adult↗
PubMed1993

Autoimmune polyglandular failure associated with malabsorption and gastric carcinoid tumour.

A 21-year-old female with autoimmune polyglandular failure (APG) manifested by insulin-dependent diabetes mellitus (IDDM), hypothyroidism and pernicious anaemia developed severe malabsorption due to exocrine pancreatic insufficiency. Supplemental pancreatic enzymes resulted in marked improvement of steatorrhea. There was also an incidental finding of gastric carcinoid tumour. We identified only 13 other patients in our institution with either type 2 or 3 APG, one of which had significant steatorrhoea. Another patient with IDDM, hypothyroidism and pernicious anaemia had an asymptomatic gastric carcinoid tumour. The possible mechanisms for malabsorption in APG are discussed.

Adult↗
PubMedDate not supplied

Protection from cell death in cultured human fetal pancreatic cells.

Endocrine cells from the human fetal pancreas will proliferate in vitro on extracellular matrix but lose hormone expression, and redifferentiation requires removal of the expanded cells from the matrix and reaggregation into cell aggregates. However, extensive cell death occurs during manipulation and culture. The mechanism of cell death was examined at each stage throughout the process under different experimental conditions to determine optimal protocols to increase cell viability. During shipment, the addition of trehalose to the media to prevent necrosis increased yield 17-fold, while during culture as islet-like cell clusters the apoptosis inhibitor Z-VAD increased yield 1.8-fold. Following disruption of cell matrix interactions and reaggregation, there was marked evidence of apoptotic bodies by the TUNEL assay. Addition of nicotinamide or Z-VAD, or removal of arginine from the media during reaggregation, reduced the number of apoptotic bodies and the effect was additive. However, a combination of treatments was necessary to significantly increase the yield of viable cells. We conclude that cell death of human fetal pancreatic tissue in culture results from both necrosis and apoptosis and that understanding the mechanisms at the cellular level will lead to protocols that will improve cell viability and promote beta-cell growth.

Amino Acid Chloromethyl Ketones↗