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Michel Neufeld

Goethe University Frankfurt

Publishes on Growth Hormone and Insulin-like Growth Factors, Neuroendocrine Tumor Research Advances, Diabetes and associated disorders. 18 papers and 2k citations.

18Publications
2kTotal Citations

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Top publicationsby citations

Two Types of Autoimmune Addisonʼs Disease Associated with Different Polyglandular Autoimmune (PGA) Syndromes
Cited by 540

A review of 295 patients with autoimmune Addison's disease which occurred as part of a polyglandular autoimmune syndrome is presented. Information of 41 cases was obtained from our clinics and from the examination of medical records, while 254 cases were culled from the literature. We report that autoimmune Addison's disease in association with other autoimmune diseases occurs in at least two distinct types. Addison's disease occurring in Type I polyglandular autoimmune disease (PGA) is associated with chronic mucocutaneous candidiasis and/or acquired hypoparathyroidism. The age of onset is predominately in childhood or in the early adult years. Type I PGA syndrome is also frequently associated with chronic active hepatitis, malabsorption, juvenile onset pernicious anemia, alopecia and primary hypogonadism. Insulin requiring diabetes and/or autoimmune thyroid disease are infrequent. In contrast, Addison's disease in Type II PGA is associated with insulin requiring diabetes and/or autoimmune thyroid disease(s). Although the age of onset of Addison's disease in Type II PGA syndrome is not confined to any age group or any specific sex, it occurs predominately in the middle years of life in females. The associated autoimmune diseases found in Type I disease, such as chronic active hepatitis, etc. (see table II) are rare in Type II PGA disease except for a low frequency of gonadal failure. We provide evidence to support the concept that the Addison's diseases in Type I and II PGA syndromes have different genetic bases, as related to HLA haplotypes, and possibly have different underlying pathogeneses.

The Somatostatin Analog SMS 201-995 Induces Long-Acting Inhibition of Growth Hormone Secretion without Rebound Hypersecretion in Acromegalic Patients*
Steven W. J. Lamberts, R. Oosterom, Michel Neufeld et al.|The Journal of Clinical Endocrinology & Metabolism|1985
Cited by 178

The acute effect of the somatostatin analog SMS 201-995 (SMS) was investigated in eight acromegalic patients. This substance is an octapeptide [DPhe-Cys-Phe-D-Trp-Lys-Thr-Cys-Thr-(ol)] that inhibits GH release in experimental animals and man. After a control day, 50 micrograms SMS were injected sc, and plasma GH and insulin and blood glucose levels were measured at multiple intervals for 24 h. GH significantly (P less than 0.001) decreased in seven of eight acromegalic patients from 30 +/- 5 (+/- SE) to an average of 10.7 +/- 4 micrograms/l from 1-10 h after drug administration. No rebound effect occurred. Postprandial blood glucose levels were significantly (P less than 0.01) higher between 2 and 4 h after SMS treatment compared with control day values, and there was a substantial reduction in insulin secretion, as estimated by the area under the curve (P less than 0.01), during the first 3 h after SMS administration. Circulating GH was not altered by SMS or the dopamine agonist mesulergine in one patient, but the combination of both substances (50 micrograms SMS, sc, and 0.5 mg mesulergine, orally) reduced GH to below 50% of basal. In vitro studies showed that 1 PM, 0.1 nM, and 10 nM SMS or natural somatostatin exerted a similar inhibitory effect (12-39% reduction; P less than 0.01 for all three strengths) on GH release by cultured human pituitary tumor cells. In conclusion, the somatostatin derivative SMS exerts a potent and prolonged inhibitory action on GH secretion and a shorter lasting suppression of insulin in acromegalic patients. Therefore, it may represent a useful tool in the chronic management of this condition.

Stimulation of insulin secretion reveals heterogeneity of pancreatic B cells in vivo.
Y Stefan, P. Mêda, Michel Neufeld et al.|Journal of Clinical Investigation|1987
Cited by 155Open Access

We examined the immunofluorescence and ultrastructural changes of insulin-producing B cells in the center and at the periphery of islets of Langerhans during in vivo stimulation by glucose and glibenclamide. A decreased insulin immunostaining was detected in islets from the splenic rat pancreas after 1.5 h of glucose stimulation. By contrast, immunofluorescence changes became apparent in islets from the duodenal pancreas only after greater than 3 h of hyperglycemia. In both cases, the immunolabeling of central B cells decreased before that of peripheral B cells. Similar changes were seen following in vivo stimulation of insulin secretion by glibenclamide. At the ultrastructural level, hyperglycemia decreased the volume density of B cell secretory granules and increased that of rough endoplasmic reticulum and Golgi apparatus. These changes were also detected earlier in central than in peripheral B cells and earlier in splenic than in duodenal islets. The data show that B cells form a heterogeneous population in vivo.