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Biomedical subjects

N Neufeld

Publications and source records attributed to N Neufeld.

10 recordsLinked to original sources
PubMed1991

Deletion of 20p 11.23----pter with normal growth hormone-releasing hormone genes.

Using a molecular analysis of the DNA from a patient with a deletion of chromosome 20 [46,XX,del(20)(p 11.23)], we have excluded the growth hormone-releasing hormone (GHRH) gene from the region 20p11.23----pter. The patient had minor facial anomalies. Rieger eye anomaly, a congenital heart defect, severe failure to thrive, and a neurosecretory problem in growth hormone (GH) secretion. Since the GHRH gene was previously mapped to chromosome 20, we used molecular genetic methods to determine whether the growth abnormalities were due to the deletion of this gene. DNAs of the patient and 2 normal control subjects were analyzed by quantitative Southern blotting using a DNA probe for the GHRH gene and 2 reference DNA probes mapping to chromosome 21. The GHRH gene was found to be present in 2 copies in the patient. This indicates that the gene for GHRH maps to the region outside the patient's deletion, in 20p11.23----qter. Furthermore, our results suggest that genes other than GHRH on 20p are important for developmental steps leading to normal neurosecretory function of GH and may also be involved in generating Rieger eye anomaly. Finally, GH deficiency and Rieger eye anomaly should be sought in other patients with deletions of 20p.

Child↗
PubMed1989

Mineral balance (iron, aluminum, copper, zinc) after high-dose intravenous Desferal in a child with hemoglobin Hammersmith and Turner's syndrome.

A 12-day balance study with measurements of urine and stool excretion was undertaken to determine the effects of intravenous (i.v.) Desferal (293 mg/kg/24 h x 2) on iron, aluminum, copper, and zinc in a child with Hemoglobin Hammersmith and Turner's syndrome treated as a thalassemia major patient because of symptoms of anemia and ineffective erythropoiesis. Iron balance was positive, 34 mg/3 days baseline. The Desferal infusion induced iron excretion of 117 mg over 48 h, almost equally in stool and urine. This child receives approximately 20 transfusion/i.v. Desferal treatments yearly. If iron excretion is roughly the same with each treatment, it would equal 2,340 mg or 47% of her annual iron intake from transfusion. The i.v. infusions are an important part of this patient's therapy and may also be useful for other chronic transfusion patients for whom subcutaneous Desferal is inadequate for preventing continued iron accumulation. Some patients have successfully received their i.v. Desferal therapy at home, thereby decreasing hospitalization time and cost. Desferal induced moderate aluminum excretion in urine but had no effect on copper or zinc excretion.

Child↗
PubMed1984

Mechanisms of the fasting-induced dissociation of insulin binding from its action in isolated rat hepatocytes.

Fasting leads to an increase in insulin binding to isolated rat hepatocytes from 12 to 17%. This increase was accounted for by changes in the affinity of insulin receptors without alteration in their number. In contrast, the responsiveness of hepatocytes to insulin was markedly diminished in fasted rats. Both basal and insulin-stimulated rates of 14C-glucose incorporation into glycogen were significantly decreased in fasted animals. When insulin-induced 14C-glucose incorporation into glycogen was expressed as a percent above the basal rate, hepatocytes isolated both from control and fasted animals showed the same magnitude of maximal response (66 +/- 13% in fed and 59 +/- 12% in fasted animals, respectively). However, more insulin must be bound to hepatocytes isolated from fasted animals in order to elicit the same percent of insulin's maximal effect. Incubation of 'fed' hepatocytes in the serum obtained from fasted rats significantly diminished their responsiveness to insulin. An addition of insulin (100 ng/ml), glucose (10 mM) and antibodies to glucagon (1:100) eliminated the inhibitory effect of 'fasted' serum on 'fed' hepatocytes. A 48-hour fast increased significantly the microviscosity (decreased fluidity) of hepatocyte plasma membranes and altered membrane phospholipid composition. These changes correlated with enhanced insulin binding to isolated membranes. Moreover, in response to insulin, plasma membranes isolated from 'fasted' hepatocytes generated only one half the amount of the second messenger (PDH activator) observed in membranes of fed animals. The amount of PDH activator generated by incubation of plasma membranes with insulin correlated inversely with both insulin binding and membrane microviscosity. We conclude that 1) fasting induces both coupling defect and post-receptor changes in insulin's action; 2) both extracellular and intracellular factors contribute to fasting-induced dissociation of insulin binding from insulin action; 3) insulin/glucagon ratio may influence hepatocyte responsiveness to insulin; 4) alterations in plasma membrane fluidity and phospholipid composition may alter insulin binding and contribute to its dissociation from the subsequent action; 5) membranes isolated from 'fasted' hepatocytes generate less mediator of insulin action than do membranes isolated from 'fed' hepatocytes.

Animals↗
PubMed1984

The effect of informational feedback on food intake of adult burn patients.

The effect of informational feedback on the protein and caloric consumption of burn patients was investigated using a multiple-baseline across subjects. The patients were four severely burned adult males who failed to consume sufficient foods to achieve prescribed levels of protein or kilocalories via standard burn unit procedures during recovery. Feedback consisted of informing patients of (a) their prescribed levels of protein and kilocalories, (b) the protein and kilocalorie content of hospital foods and beverages, and (c) their actual intake of protein and kilocalories. Following the provision of feedback, there was an increase in protein and kilocalorie intakes and in the number of days during which prescribed levels for protein and kilocalories were achieved. These results suggest that the informational feedback was effective for improving the oral caloric intake of burn patients.

Adolescent↗
PubMed1984

Insulin receptors and placental proteins in normal and gestational-diabetic pregnancies.

We studied 125I-insulin binding to monocytes and plasma levels of two trophoblastic proteins from 38 pregnant patients with varying degrees of carbohydrate intolerance, including 10 pregnant controls (PC), 17 Class A diabetics (A), 6 Class B diabetics - prior to insulin therapy (B-noRx) and 5 different Class B diabetics studied 1-6 weeks following initiation of insulin therapy (B-Rx). All studies were performed in the second half of pregnancy. In comparison to six age- and weight-matched nonpregnant controls (NPC), insulin binding to monocytes was somewhat higher in both PC and A. B.noRx patients had significantly lower tracer binding than did PC (0.71 +/- 0.3 vs 2.6 +/- 0.6%/10(7) cells, p less than 0.01). Insulin treatment of Class B patients restored insulin tracer binding levels to above normal. Levels of human placental lactogen (HPL) were significantly elevated in B-noRx patients compared to PC and A and were lowered to levels comparable to normal in insulin-treated B patients. A highly significant inverse relationship existed between HPL levels and the tracer binding of insulin for all patients studied (r = -0.52, p less than 0.005). Elevations of pregnancy-specific beta 1 glycoprotein were observed in patients with mild carbohydrate intolerance (A) as well as Bno-Rx, but were comparable to normal in those B-patients receiving insulin therapy. There were no significant differences of insulin binding or receptor number in the patient groups in the postpartum state. This further supports the hypothesis that placental factors may be responsible for the insulin binding defects seen in gestational diabetes.

Female↗
PubMed1981

Monocyte insulin binding studies in normal and diabetic pregnancies.

Monocyte insulin receptor binding was studied in six nonpregnant control patients and in 40 pregnant patients with varying degrees of carbohydrate tolerance. Competitive binding assays were performed to determine insulin binding to monocytes. Fasting insulin levels were determined. We obtained the following results: (1) When compared to values not associated with pregnancy, the number of insulin receptor sites per cell increases twofold (31,000 versus 16,300); (2) Class A diabetic patients have higher numbers of receptor sites than normal pregnant patients (80,800 versus 31,000; (3) untreated Class B diabetic patients have markedly reduced receptor sites (4,575) and bind less insulin at physiologic concentrations (p less than 0.01); (4) insulin therapy of previously untreated Class B diabetic patients restored the number of receptor sites to normal pregnant levels (29,700); and (5) Classes C and D diabetic patients had similar numbers of receptor sites (30,140) and showed a greater receptor affinity for insulin than pregnant control subjects (p less than 0.01).

Adult↗
PubMed1981

Benign macro-orchidism in a pubescent boy.

We report on a 12 1/2-year-old boy with bilateral testicular enlargement. After an extensive evaluation we eliminated precocious puberty, hypothyroidism, congenital adrenal hyperplasia, X-linked mental retardation and bilateral malignant testicular neoplasms from consideration. Diagnosis was benign macro-orchidism. The clinical and laboratory features of this condition are sufficiently distinct from the other causes of testicular enlargement to allow a diagnosis to be made without testicular biopsy or orchiectomy.

Child↗
PubMed1981

3,5-Dimethyl-3'-isopropyl-l-thyronine therapy in diabetic pregnancy: stimulation of rabbit fetal lung phospholipids.

Diabetes mellitus in pregnancy is associated with neonatal respiratory distress syndrome due to impaired synthesis of fetal lung surfactant. Pharmacologic agents that promote fetal lung maturity are diabetogenic and have limited use in the management of diabetic pregnancy for prevention of respiratory distress syndrome. Maternal administration of a thyroid analog 3,5-dimethyl-3'-isopropyl-L-thyronine (DIMIT) results in significant enhancement of fetal lung phospholipid synthesis and accelerated lung maturity. We therefore studied the effects of DIMIT (0.5 mg/kg per d, s.c.) administration to pregnant alloxan-diabetic rabbits on days 25 and 26 of gestation. DIMIT treatment of diabetic maternal rabbits (DD) was associated with reduction of maternal blood glucose (115 +/- 13 vs. 275 +/- 72 mg/dl, P less than 0.05) and fetal glucose (64 +/- 6 vs. 274 +/- 47 mg/dl, P less than 0.001) compared with saline-injected diabetic (D) mothers. Reduction of fetal insulin levels was also associated with maternal DIMIT therapy in diabetic rabbits (56 +/- 5 (D) vs. 24 +/- 4 microunits/ml, P less than 0.001). Maternal diabetes resulted in significant reduction of fetal lung weight (370 +/- 20 vs. 520 +/- 30 mg, P less than 0.005) and lung protein content (6.5 +/- 0.7 vs. 8.7 +/- 0.7 mg/gm, P less than 0.005), which were restored to normal in offspring of DIMIT-treated diabetic rabbits. Maternal DIMIT administration caused significant reduction in fetal lung glycogen content in control (62 +/- 5.8 vs. 25 +/- 5.9 micrograms/mg protein, P less than 0.001) and diabetic (56 +/- 7 vs. 34 +/- 5 micrograms/mg protein, P less than 0.02) offspring. Whereas maternal diabetes was associated with reduction of all major phospholipid species in fetal lung-comprising surfactant, these were restored with DIMIT therapy. The results demonstrate that short-term maternal administration of DIMIT in pregnant diabetic rabbits not only promotes fetal lung phospholipid synthesis, but also appears to ameliorate maternal hyperglycemia. Thus, DIMIT is of potential benefit in the management of diabetic pregnancy.

Animals↗
PubMed1975

Ischemic heart disease and pulmonary ventilatory function.

The results of spirometric examinations on 4, 331 Israeli male civil service employees, aged 45 years or more, were analyzed according to the presence or absence of certain aspects of ischemic heart disease. Vital capacity was lower in individuals with a previously history of a heart attack, in those with definite or suspected angina pectoris and in those with ECG evidence of myocardial ischemia, probable or possible myocardial infarction, left bundle branch block or nonspecific T wave changes in subjects without these findings. The differences were small, but statistically significant. Vital capacity was lower in subjects with a recent history of a heart attack (within three years) than in those whose heart attack had occurred more than three years prior to the examination. The ratio of forced expiratory volume in the first second to forced vital capacity was not significantly different between individuals with or without a past history of heart attack, angina pectoris or ECG evidence of coronary heart disease.

Angina Pectoris↗