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Biomedical subjects

J F Marks

Publications and source records attributed to J F Marks.

At least 19 recordsLinked to original sources
PubMed1992

Effect of somatotropin of mammalian cell origin in growth hormone deficiency.

Sixty-nine growth hormone-deficient patients were treated for 1 year with somatotropin (recombinant DNA-derived human growth hormone) produced in mouse cells. The growth velocity of the 50 patients (72%) in whom the effectiveness of this growth hormone could be evaluated increased from a mean (+/- SD) of 3.5 +/- 1.1 to 8.7 +/- 1.6. cm/y. An enhanced rate of weight gain was also observed. Bone age was not unduly accelerated. One of 66 patients developed antibodies to recombinant growth hormone, which did not affect the response to therapy. No patient developed antibodies to host cell proteins. An increased insulin response to a standard glucose load, without any change in glucose tolerance, was observed after 1 year of treatment. This authentic sequence human growth hormone preparation produced in mammalian cells is both effective and safe in the treatment of children with growth hormone deficiency.

Adolescent↗
PubMed1991

Long term observations in a patient with pseudohypoaldosteronism.

This paper describes a patient with severe pseudohypoaldosteronism (PHA) for over 12 years. The patient presented at 10 days of age with a serum sodium of 118 mEq/l and potassium of 12 mEq/l. After failing to maintain normal fluid and electrolyte status with standard therapy, including maximal mineralocorticoid stimulation, he was given a special formula containing minimal potassium plus salt supplements which normalized his electrolyte status. However, when he was 4.5 years of age, an acute gastrointestinal illness led to severe volume depletion, hyperkalemia, and cardiopulmonary arrest. This resulted in significant neurological impairment. At 12.5 years of age, the patient continues to require massive sodium supplements and his diet contains less than 0.5 mEq/kg potassium daily; his height and weight are at the 95th percentile, thus demonstrating that normal growth may be achieved with strict dietary manipulation in a patient with persistent, severe PHA. Serial studies to further define the lesion in this patient have demonstrated: (1) normal binding of aldosterone to aldosterone binding globulin (5.1% bound); (2) normal mineralocorticoid "activity"; (2) suppressible renin and aldosterone levels; (4) increased prostaglandin excretion (3.15 micrograms/g creatinine); (5) lack of benefit of prostaglandin inhibition with indomethacin; (6) normal proximal tubule function (CNa + CH2O = 18.0 ml/100 ml glomerular filtration rate; (7) impaired distal tubule function (CH2O/CNa + CH2O = 79.8%) during water diuresis.

Aldosterone↗
PubMed1991

In vivo and in vitro studies on the effects of vitamin A on the chemiluminescent response of murine peritoneal exudate cells.

Retinoids are known to enhance macrophage function and enhance bacterial clearance during experimental infection. The purpose of these experiments was to determine if one indicator of macrophage activation, chemiluminescence (CL), was enhanced by retinoids. Peritoneal exudate cells (PEC) harvested from mice injected intraperitoneally for 5 days with retinol palmitate (25, 125, or 250 U/g body wt./d) showed significantly enhanced chemiluminescence (CL) when exposed to opsonized zymosan. A direct dose-response effect was observed, in that the more retinol palmitate was injected, the more CL was observed. The same dose of retinol palmitate injected subcutaneously did not result in enhanced CL. In vitro incubation of murine PEC with physiological concentrations of retinol palmitate or retinoic acid for 1, 6 or 24 h did not result in enhanced CL. The reasons for the effect of the route of administration of retinol palmitate are unknown, but may include poor absorption from the site of subcutaneous injection or an adjuvant effect when injected intraperitoneally due to the particulate nature of the water-dispersible retinol palmitate preparation.

Animals↗
PubMed1990

Maternal meiosis II nondisjunction in a case of 47,XXY testicular feminization.

An 11-year-old patient with incomplete testicular feminization and a 47,XXY karyotype is described. The patient had female external genitalia, clitoromegaly, and some features of Klinefelter's syndrome, including speech delay and delayed intellectual development. DNA analysis using X chromosomal DNA sequences suggest that the supernumerary X chromosome in the patient resulted from maternal nondisjunction during meiosis II. The M II error thereby provides the basis for homozygosity of a mutation in the androgen receptor locus.

Androgen-Insensitivity Syndrome↗
PubMed1990

Follicle regulatory protein: a novel marker for granulosa cell cancer patients.

Follicle regulatory protein (FRP) is secreted by the granulosa cell of the ovary and plays a role in modulating follicle development. A dual epitope immunoassay using two murine monoclonal antibodies, isotype IgG1 (raised against porcine FRP), in tandem was developed to measure FRP in serum. The levels of FRP in the serum of women with granulosa cell tumors, normal, menstruating women, and postmenopausal women were determined. The levels of FRP were elevated in the serum of 79% of the women with granulosa cell tumors compared to the normal controls. FRP levels in serial samples from women with granulosa cell tumors generally correlated with the clinical course of the disease. Thus, FRP may provide a useful marker for granulosa cell tumors.

Adult↗
PubMed1983

Relative hyperglucagonemia in L-asparaginase-and prednisone-induced glucose intolerance in management of acute lymphocytic leukemia.

Ten children with acute lymphocytic leukemia developed transient diabetes mellitus during treatment with L-asparaginase and prednisone. Serum glucose, plasma insulin, and plasma glucagon levels were measured when the patients were hyperglycemic. Six of the children were restudied several months later when there were no clinical or laboratory signs of glucose intolerance. Hyperglycemia induced by L-asparaginase and prednisone was associated with depression of plasma insulin and, despite the inhibiting action of L-asparaginase on protein synthesis, a corresponding elevation of plasma glucagon. Thus patients with diabetes mellitus induced by L-asparaginase and prednisone have relative hyperglucagonemia similar to other patients with diabetes mellitus.

Adolescent↗
PubMed1979

Low-dose continuous intravenous insulin infusion in childhood diabetic ketoacidosis.

We studied 58 children with diabetic ketoacidosis using a random, prospective protocol, with insulin administered either as a low-dose continuous infusion or as high-dose intermittent subcutaneous injections. There were no statistically significant differences between admission pH and glucose determinations or the time to metabolic correction. The incidence of hypoglycemia and hypokalemia was higher in patients receiving subcutaneous insulin. Insulin levels in the low-dose patients were 85--160 microU/ml. The insulin required to achieve metabolic recovery was 1.6 U/kg in the low-dose group and 4.5 U/kg in the high-dose group (p less than 0.01). Glucose administered at a rate of 3 to 4 g er unit of insulin infused in the low-dose group maintained a serum glucose of 150 to 250 mg/dl. Our studies suggest that low-dose intravenous insulin therapy is safe, as effective as high-dose intermittent subcutaneous injections and avoids the risks of hypoglycemia and hypokalemia. Meticulous attention to individual patient care, however, must remain the most important single variable.

Child↗
PubMed1979

Physiologic responses of juvenile-onset diabetic boys to muscular work.

The cardiorespiratory and metabolic responses of juvenile-onset diabetic (Dia) and nondiabetic (Con) boys to light, moderate, and maximal treadmill work were investigated. No significant differences were observed between the Dia and Con subjects in cardiorespiratory responses to maximal and submaximal work. The mean values for the Dia boys during maximal treadmill work for ventilatory volume, oxygen uptake, heart rate, and lactic acid were 91.5 L/min, 54.9 ml/kg . min, rate, and lactic acid were 91.5 L/nin, 54.9 ml/kg . min, 198 beats/min, and 7.0 mM/L, respectively. In the Dia boys, maximal-, light-, and moderate-intensity work produced significant plasma glucose decreases (P less than 0.05) of 1.64, 3.23, and 7.2 mM/L, respectively. In the Con boys, the submaximal work bouts were performed without significant change in plasma glucose levels, but glucose levels after maximal work were elevated 1.58 mM/L. Light and moderate work in both groups produced no changes in plasma triglycerides, free fatty acids, or lactic acid. However, for the Dia boys, maximal work was associated with a significant increase of 0.36 mM/L in triglycerides.

Adolescent↗
PubMed1978

Systemic carnitine deficiency. Report of a fatal case with multisystemic manifestations.

A 14-year-old boy presented with recurrent and intractable hypoglycemia. He developed marked hepatic dysfunction and a severe myopathy. The diagnosis of systemic carnitine deficiency was not made until after his death from acute cardiac arrest. The recognition that systemic carnitine deficiency may present with multisystemic manifestations may allow earlier diagnosis and potentially effective replacement therapy in other patients so afflicted.

Adolescent↗
PubMed1978

Luteinizing hormone and follicle-stimulating hormone secretory dynamics in Turner's syndrome.

In eight teenage patients with Turner's syndrome, LH and FSH were measured at 20-min intervals for 24 h. The 24-h mean LH and FSH levels ranged from 20.2-70.5 mIU/ml and 60.4-229 mIU/ml, respectively. There was a significant positive correlation between the individual LH and FSH levels in the eight patients; the common correlation coefficient was 0.449 (P less than 0.001). The 24-h mean estradiol level was measurable in only two of the patients and the 24-h mean testosterone level for the eight patients was 0.10 ng/ml. The mean LH concentration during sleep was significantly higher (P less than .01) than during waking. The mean FSH concentration during sleep was also significantly higher (P less than 0.05) than during waking. The LH and FSH peak levels after LRH were significantly correlated with the 24-h mean LH (r = 0.918; P less than 0.01) and FSH concentrations (r = 0.754; P less than 0.05), respectively.

Adolescent↗
PubMed1978

Studies of gonadotropin-gonadal dynamics in patients with androgen insensitivity.

Four patients with androgen insensitivity had plasma LH and FSH measured at 20-min intervals for 24 h and at 15- to 30-min intervals for 3 h after the injection of LRH. Twenty-four-hour mean testosterone (T), estradiol, and androstenedione (delta 4) levels were also measured. Patients with androgen insensitivity had significantly elevated LH levels (P less than 0.05) and an increase in the number of LH secretory episodes (P less than 0.001) compared to normal subjects. The amplitude of the LH secretory episodes, expressed as the absolute increment, was significantly higher than normal controls (P less than 0.005). The LH response to LRH (absolute increment) was twice that of normal, but was not significantly different from normal subjects. The 24-h mean FSH levels were normal in three of the patients and elevated in one. This patient had the mildest degree of androgen insensitivity on clinical exam and the greatest degree of testicular atrophy. The 24-h mean T, estradiol, and delta 4 levels were higher than normal, but only the delta 4 was significantly increased (P less than 0.05). To determine if the elevated LH levels were in response to a decrease in the free T level, we measured T-binding capacity (TBG), TBG was higher than normal controls but was not significantly different, suggesting that elevated LH levels were probably in response to a decrease in T action at the hypothalamic-pituitary level. This was further supported by the inability of prolonged dihydrotestosterone administration to affect LH secretion in one of the patients with the Reifenstein syndrome.

Adolescent↗
PubMed1978

LH and melatonin secretion patterns in pubertal boys.

Four normal pubertal boys had plasma LH and melatonin measured at 20-minute intervals for 24-hours. All four subjects showed a significant augmentation of LH and melatonin during nocturnal sleep. There was also a significant correlation between the LH and melatonin levels (P less than 0.001). These data indicate that the peripheral concentrations of melatonin which occur during sleep are insufficient to prevent spontaneous LH secretion during puberty.

Adolescent↗
PubMed1977

Massive extranglandular aromatization of plasma androstenedione resulting in feminization of a prepubertal boy.

This report describes the mechanism of origin and the quantity of estrogen produced in a prepubertal boy who developed severe feminization at 8 yr of age as the result of a heretofore undescribed metabolic abnormality. The clinical findings were gynecomastia and accelerated linear growth and bone maturation. At the time feminization developed, there were no signs of growth or development of the otherwise normal prepubertal male external genitalia or any increase of muscle mass that normally accompanies male puberty. The hyperestrogenism was found to be the consequence of massive extraglandular conversion of plasma androstenedione to estrone. During a 6-mo period of study, the plasma production rate of androstenedione ranged from 1.2 to 1.6 mg/day. More than 55% of plasma androstenedione was metabolized by aromatization to estrone which, in turn, was extensively sulfurylated in the tissue sites of aromatization before its entry into the blood. Thus, estrone sulfate was the final product in the aromatizing sites, and the plasma production rate of estrone sulfate derived from plasma androstenedione was 782 mug/24 h. The extent of extraglandular conversion of plasma androstenedione to estrone measured in this boy was 50 times that observed in two normal prepubertal boys. Moreover, 94% of the extraglandular aromatization occurred in extrahepatic sites. The metabolic clearance rate of plasma androstenedione, 2,380 liters/day per m(2), was markedly increased in this boy. Approximately 1,500 liters of plasma androstenedione clearance was accounted for by extrahepatic, extraglandular aromatization. The fractional conversion of testosterone to estradiol, 0.16, was 50 times greater in this boy than that observed in normal young adult men. The total extent of aromatization of plasma prehormones was even greater in this boy inasmuch as evidence was obtained that aromatization of 16-hydroxysteroids, e.g. 16alpha-hydroxy androstenedione and 16alpha-hydroxy dehydroisoandrosterone (sulfate), resulted in estriol formation independent of estrone formation. Thus, extensive extrahepatic, extraglandular aromatization resulted in advanced feminization in this prepubertal boy by a previously undescribed metabolic abnormality.

Androstenedione↗
PubMed1975

Capillary basement membrane width in diabetic children.

The effect of juvenile onset diabetes mellitus on quadriceps muscle capillary basement membrane (QCBM) width has been examined by the electron microscopic morphometric method previously developed in this laboratory. The results demonstrate that in this age group QCBM thickening is strongly related to the age of the diabetic subject. As a result, in contrast to the almost constant thickening of QCBM that has consistently been documented in diabetic adults, QCBM hypertrophy is present in only 40 per cent of children with diabetes mellitus. As was previously shown to be the case in adults, in children, too, QCBM thickening is unrelated to the duration of the diabetes. Finally, the finding that QCBM hypertrophy is present at the time of acute onset of juvenile diabetes mellitus in 30 per cent of children, coupled with the fact that this lesion is not affected by duration of hyperglycemia, strongly supports our previous conclusion that diabetic microangiopathy is independent of the hyperglycemia of this disease. On the other hand, barring the possibility that microangiopathy in the pancreas precedes that in muscle, these results represent evidence against the suggestion that basement membrane hypertrophy represents the primary lesion of the diabetic syndrome.

Adolescent↗
PubMed1975

Voluntary unilateral convergent strabismus.

This syndrome has been reported as a medical rarity. However, 16 cases, including 2 families, add to knowledge of the occurrence, age of onset, emotional factors, and to possible genetic basis in the etiology.

Adolescent↗