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Biomedical subjects

D M Wilson

Publications and source records attributed to D M Wilson.

At least 235 records · Page 13Linked to original sources
PubMed1986

Changes in the polypeptide composition of mouse parotid glands after stimulation of secretion and DNA synthesis by isoproterenol.

The polypeptide composition of mouse parotid glands has been analysed by unidimensional SDS-polyacrylamide slab gel electrophoresis and Coomassie blue staining after isoproterenol stimulation of secretion and DNA synthesis. Two polypeptides (polypeptides A and B) are lost within 2 h and their restoration in the glands occurs according to a chronology which is identical to that of the alpha-amylase activity. On the other hand, five clearly defined new bands appear consistently during the late prereplicative period of isoproterenol-stimulated mouse parotid acinar cells (polypeptides C, D, E, F and G). These new polypeptides are induced by doses of isoproterenol which provoke secretion and DNA synthesis, but not by doses which provoke only secretion. Although no function has been assigned to any of the above-described polypeptides, a relation between polypeptides A and B and secretion and between polypeptides C, D, E, F and G and the proliferative response is suggested.

Animals↗
PubMed1986

Insulin-like growth factors I and II in evaluation of growth retardation.

Plasma samples from 68 growth hormone (GH)-deficient children (provocative serum GH level less than 7 ng/ml), 44 normal short children, and 197 children with normal height were assayed by specific radioimmunoassays for the somatomedin peptides, insulin-like growth factors (IGF)-I and -II. Eighteen percent of the GH-deficient children had IGF-I levels within the normal range for age, whereas 32% of normal short children had low IGF-I levels. Low IGF-II levels were found in 52% of GH-deficient children, but also in 35% of normal short children. However, only 4% of GH-deficient children had normal plasma levels of both IGF-I and IGF-II. Furthermore, only 0.5% of normal children and 11% of normal short children had low plasma levels of both IGF-I and IGF-II. We conclude that plasma levels of either IGF-I or IGF-II overlap in GH-deficient and normal short children, but that the combination of radioimmunoassays may permit better discrimination among normal, normal short, and GH-deficient children.

Adolescent↗
PubMed1986

The renal, forearm, and hormonal responses to standing in the presence and absence of propranolol.

Nine normal volunteers underwent assessment of renal, forearm, and hormonal responses to orthostasis (quiet standing) in the presence and absence of 1 week of oral propranolol (160 mg/day). This was done to test the hypothesis that physiologic decrements in renal function (glomerular filtration rate, effective renal plasma flow, and absolute urinary sodium excretion) are attenuated by propranolol during quiet standing. The present studies, however, demonstrate that propranolol exaggerates the physiologic decrement in glomerular filtration rate, effective renal plasma flow, and absolute urinary sodium excretion during orthostasis. Forearm and renal vascular resistances were also accentuated in the presence of propranolol during quiet standing. These responses were associated with significant increases in plasma norepinephrine. We conclude that long-term administration of propranolol accentuates the physiologic decrement in renal hemodynamic and excretory function as well as in the forearm hemodynamic response to orthostasis in normal subjects.

Adult↗
PubMed1986

Sex chromosome fragment in a phenotypically normal female. Significance of occult Y-related material.

The authors report a 15-year-old short, nonvirilized, prepubertal female whose peripheral karyotype revealed a mosaicism in which 62 percent of the cells had a karyotype of 45X, and the other 38 percent had a karyotype of 46X plus a small unidentified marker chromosome. Since the authors were unable to determine from the karyotype whether this marker was derived from an X or a Y chromosome and because of the high risk for neoplasia in abnormal gonads containing Y material, she underwent surgical exploration, with removal of gonadal tissue. Microscopic examination of the streak gonads revealed a mixture of dysgenetic ovarian and testicular type tissues. The presence of testicular-like tubules strongly implied the presence of Y material in the genotype. Review of the literature reveals at least 19 similar cases in which presumed sex chromosomal markers or fragments were found in phenotypically normal females. Because of the risk of gonadal neoplasia in patients with occult Y chromosomal material, gonadectomy is indicated when the origin of the marker chromosome is uncertain.

Adolescent↗
PubMed1986

Acromegaly and pheochromocytoma: a multiple endocrine syndrome caused by a plurihormonal adrenal medullary tumor.

A 42-yr-old man with congestive heart failure and diabetes mellitus was found to have acromegaly and a pheochromocytoma. Serum GH-releasing hormone (GHRH) levels were elevated (2.34 ng/dl; normal, less than 0.02 ng/dl), suggesting that the acromegaly was caused by ectopic secretion of GHRH. Postmortem examination revealed that the right adrenal gland contained a pheochromocytoma in which GHRH was demonstrated by immunohistochemical studies. Gel permeation chromatography combined with the use of two GHRH antisera showed that GHRH-(1-44)-NH2 was a predominant form of the hormone. When the RNA from the tumor was extracted and analyzed by Northern gel blotting, two mRNA species were identified, with transcripts corresponding to 1600 and 780 base pairs. The pituitary gland was enlarged, but no distinct adenoma was found. Diffuse and nodular hyperplasia of somatotrophs in some areas resembling adenoma was identified on histological examination. These findings indicate that GH excess accompanied by somatotroph hyperplasia and acromegaly were secondary to a pheochromocytoma which secreted not only catecholamines but also GHRH.

Acromegaly↗
PubMed1986

Reduction of pituitary size by the somatostatin analogue SMS 201-995 in a patient with an islet cell tumour secreting growth hormone releasing factor.

Acromegaly is rarely caused by the ectopic secretion of growth hormone releasing factor (GRF) from peripheral neuroendocrine tumours. We evaluated the ability of a recently developed somatostatin analogue (SMS 201-995, Sandoz) to reduce hormone levels and pituitary size in a young woman with acromegaly and Zollinger-Ellison syndrome secondary to a metastatic pancreatic islet cell tumour secreting GRF and gastrin. Gastrin, GRF, and growth hormone (GH) levels declined dramatically following the initiation of therapy with the analogue by continuous iv infusion. Although intermittent sc therapy was not effective in suppressing hormone levels, continuous sc infusion of SMS 201-995 has provided good control of both GRF and GH levels for nine months. Moreover, treatment with SMS 201-995 was associated with a substantial reduction in pituitary enlargement and an improvement in her gastric symptoms. Continuous sc infusion of SMS 201-995 may be useful in treating enlarged pituitaries resistant to other modes of therapy.

Acromegaly↗
PubMed1986

Growth and intellectual development.

Data from the National Health Examination Survey (cycles II and III) provided a representative sample of 13,887 US youths (6 to 17 years of age) with which to examine the relationship between height (normalized for age and sex) and measures of intellectual development (Wechsler Intelligence Scale for Children) and academic achievement (Wide Range Achievement Test). Additionally, 2,177 subjects were studied first in cycle II and 2 to 5 years later in cycle III, forming a well-selected longitudinal study group in which to examine any association between linear growth and change in IQ scores. Wechsler Intelligence Scale for Children and Wide Range Achievement Test scores were significantly correlated with height in both cycle II and cycle III. However, no significant association between change in relative height and change in IQ scores could be detected in the longitudinal group. These data suggest that therapies designed to increase height are unlikely to alter measures of intellectual development or academic achievement.

Achievement↗
PubMed1986

Canine aflatoxicosis: a continuing problem.

Aflatoxins are hepatotoxic in many species including dogs. In two separate outbreaks, the primary signalment was high morbidity and mortality in hunting dogs presenting with clinical signs of icterus, anorexia and listlessness. Preliminary laboratory examinations revealed toxic hepatitis, bilirubinuria and anemia. In the first case, a feed sample was not available and the diagnosis was established by confirming the presence of significant levels of aflatoxin B1 in tissues. In the second case, cornmeal utilized in formulating the ration contained 511 ng aflatoxin B1 and B2/g. These cases illustrate that aflatoxicosis is a continuing problem despite widespread awareness and testing for aflatoxin.

Aflatoxins↗
PubMed1985

Increased plasma inactive renin in diabetes mellitus. A marker of microvascular complications.

Plasma renin exists in an active form or as an inactive zymogen that resembles a prorenin present in homogenates of human kidneys. We examined the relation of diabetes and its microvascular complications with the level of plasma inactive renin activated by dialysis to pH 3.3. Plasma inactive renin was measured in 235 diabetic patients and 90 nondiabetic controls. In the controls, the level of plasma inactive renin increased slightly with age but was never above 50 ng per milliliter per hour. In young diabetic patients studied within three years of the onset of diabetes the concentration of inactive renin was normal, and in some older diabetics without complications it remained within the age-adjusted normal range for many years. However, in patients with retinopathy or albuminuria, plasma inactive renin was above the normal range with few exceptions, reaching levels 50 to 200 per cent above the upper limits of normal in patients with nephropathy. The frequency of neuropathy was also significantly higher among patients with levels above the normal range. In 37 per cent of the diabetics followed during one to three years of conventional treatment, plasma inactive renin increased significantly, but in another group of diabetics under intensive treatment, the level rose in only 7 per cent and fell in 43 per cent. We conclude that there is a close association between a high level of plasma inactive renin and the presence of microvascular complications, and that the level of inactive renin can be modified by intensive treatment of diabetes.

Adolescent↗
PubMed1985

The measurement of arterial smooth muscle cell mitogens in the blood of oral contraceptive users.

We have previously shown that serum from young women receiving the same combined mestranol-norethindrone containing oral contraceptive (OC) preparation accelerated the proliferation of arterial smooth muscle cells (SMC) in tissue culture, and this in vitro effect was not a direct action of either of its estrogenic or progestogenic constituents. To identify the substance(s) which might contribute to this potentially atherogenic action, blood was obtained from 20 OC users and control women for the measurement of growth hormone, insulin, somatomedins (insulin-like growth factor IGF-I and IGF-II), and the platelet alpha-granule constituents platelet-derived growth factor (PDGF), beta-thromboglobulin, and platelet factor 4 (PF4). No difference was demonstrable between OC users and controls in the levels of any of these growth-promoting hormones, nor in plasma concentrations of any of the platelet alpha-granule proteins. These studies indicate that the enhanced mitogenicity found in OC sera is probably not attributable directly to these hormones or PDGF, and may instead result from an in vivo OC-induced alteration in other as yet unidentified mediators of cellular growth.

Adolescent↗
PubMed1985

The risks of unilateral nephrectomy: status of kidney donors 10 to 20 years postoperatively.

We received requested follow-up information from 105 (73%) of our 144 kidney donors who had undergone unilateral nephrectomy 10 to 20 years previously. Five donors had died of unrelated causes 6 or more years postoperatively. Studies in the remaining 100 donors showed that the current mean serum creatinine concentration was 1.2 mg/dl and the mean 24-hour urinary protein value was 89 mg. Hypertension (defined as 160 mm Hg or more systolic, 95 mm Hg or more diastolic, or both) was present in 19% of the donors. In a subgroup of 66 donors who had had serial serum creatinine determinations, the renal function, as estimated on the basis of these serum creatinine values, had not deteriorated with time. Thus, we consider unilateral nephrectomy in this group of patients relatively safe. Subsequent evaluation will be necessary to ascertain whether these findings prevail.

Adolescent↗
PubMed1985

Regulation of growth hormone release from cultured human pituitary adenomas by somatomedins and insulin.

GH secretion is stimulated by hypothalamic GH-releasing factor (GHRH) and inhibited by somatostatin. Since GH induces the production of insulin-like growth factors (IGF) in liver and other tissues, it is of interest to learn whether IGF alters GH release through long loop feedback inhibition. Pituitary adenomas which had been removed from six acromegalic patients were processed for dispersed cell cultures and/or cell membrane preparations. Binding studies using 125I-labeled IGF-I, IGF-II, and insulin revealed specific hormone binding for each ligand to cell membranes derived from four somatotropinomas. A partially purified somatomedin preparation inhibited basal and/or GHRH-stimulated GH release from cultured pituitary cells derived from three of four adenomas; there was no effect of somatomedin in one tumor. In a single tumor, insulin also partially inhibited GHRH-stimulated GH release. Additionally, in one nonadenomatous pituitary removed from a patient with diabetes mellitus, insulin and somatomedin inhibited GHRH-stimulated GH release, and insulin inhibited basal GH secretion. These results indicate that specific cell membrane receptors for somatomedin peptides and insulin may be found on cell membranes from GH-secreting tumors, and that somatomedins and insulin can inhibit GH release in cultured human somatotropinoma cells. Thus, these data suggest that somatomedins may exert feedback inhibition of GH secretion in some patients with acromegaly.

Acromegaly↗
PubMed1985

Reconstitution of the melibiose carrier of Escherichia coli.

Different conditions were studied for optimal solubilization and reconstitution of the melibiose carrier of Escherichia coli. Several alpha- and beta-galactosides, known to be substrates for the melibiose carrier, were found to inhibit [3H]-melibiose uptake by proteoliposomes. In the presence of 10 mM Na+ the Km for melibiose counterflow was 0.42 mM. Melibiose and raffinose were good substrates for counterflow, while thiomethyl-beta-galactoside and p-nitrophenyl-alpha-galactoside were accumulated very poorly. Although the latter two sugars are known to be substrates for the carrier, they showed a very rapid rate of passive diffusion across the liposome membrane. The proton ionophore carbonylcyanidechlorophenylhydrazone had no effect on uptake, suggesting that a proton motive force is not essential for the counterflow phenomenon.

Biological Transport, Active↗
PubMed1985

Subcutaneous versus intramuscular growth hormone therapy: growth and acute somatomedin response.

To determine the optimal route of growth hormone administration, a comparison was made of the acute somatomedin response and chronic growth response to either intramuscular or subcutaneous growth hormone in 20 children with growth hormone deficiency. None of the children had received growth hormone for at least 2 weeks prior to their random selection to receive growth hormone by either the subcutaneous (N = 11) or intramuscular (N = 9) route. Plasma samples for determination of levels of insulin-like growth factors I and II (IGF-I and IGF-II) were obtained prior to therapy and 20 hours after the first and fourth of four daily injections of growth hormone. Growth rate and growth hormone antibody levels were determined before and after 6 months of therapy. IGF-I levels tripled in both treatment groups after four days of growth hormone injections, whereas IGF-II levels nearly doubled, with no significant difference between the intramuscular or subcutaneous group. After 6 months of therapy, there was no significant difference in growth rate and only two patients had developed growth hormone antibodies. Both patients and parents expressed a preference for the subcutaneous method. The identical rises in the IGF-I and IGF-II levels following a brief course of either subcutaneous or intramuscular injections of growth hormone, the similar growth rates, the low incidence of antibody development, and the preference for the subcutaneous route all suggest that the subcutaneous route is the method of choice for chronic growth hormone therapy.

Adolescent↗
PubMed1985

Urinary citrate excretion in normal persons and patients with idiopathic calcium urolithiasis.

The 24-hour urinary excretion of citrate was measured in 83 normal persons and in 132 consecutive patients with idiopathic calcium urolithiasis, uninfected urine, and normal renal function. The urinary excretion of citrate in normal men was not significantly different from that in normal women (P greater than 0.05). There was a significant (P less than 0.001) increase of urinary citrate excretion with increasing age in normal persons. No increase of urinary citrate excretion with age was demonstrated in stone formers. There was no statistically significant difference between active and inactive stone formers in regard to regression of the citrate/calcium ratio or the citrate/uric acid ratio, and there was no difference in these ratios between men and women considered separately or in subgroups by hypercalciuria or hyperuricuria or by individual age. Hypocitraturia was found in 29.2% of patients with idiopathic calcium urolithiasis. No relationship could be demonstrated between the 24-hour urinary excretion of citrate and severity of stone disease before presentation at our clinic or the frequency of stone growth or new stone formation at follow-up. Twenty-two of 35 patients with hypocitraturia had multiple urinary citrate measurements. In 15 of these 22 patients, at least one normal urinary citrate measurement was obtained. Further prospective study is required to establish the value of urinary citrate determinations in patients consuming an uncontrolled diet in an outpatient setting.

Adult↗
PubMed1984

Hypertension caused by an aldosterone-secreting adenoma. Occurrence in a 7-year-old child.

A 7-year-old girl had hyperaldosteronism due to an adrenal cortical adenoma, a rare, surgically remediable cause of hypertension. Although the plasma potassium concentration was only slightly below normal, and the plasma aldosterone concentration was in a high normal range, the consistently suppressed plasma renin activity suggested primary aldosteronism. This diagnosis was confirmed by the failure of saline infusion to lower the plasma aldosterone concentration. Glucocorticoid-remediable hyperaldosteronism was excluded when dexamethasone did not reduce the high plasma aldosterone concentration. An enlarged left adrenal gland was observed in the computed tomographic scan, and blood from the left adrenal vein contained much more aldosterone than blood from the right adrenal vein. Surgical excision of the left adrenal gland, containing an adenoma, was followed by a return of BP and biochemical measurements to their normal ranges. This case demonstrated the importance of a rational systematic approach in the evaluation of children with sustained unexplained hypertension and the need to obtain plasma renin activity values when either hypokalemia is present or initial investigations fall to provide a diagnosis.

Adenoma↗