摘要:

ExtractThis paper presents a study of nocturnal penile tumescence (NPT) and the relation of this phenomenon tostage 1rapid eye movement (REM) sleep for a group of pubertal males. Ten subjects, ages 12.8 to 15.3 years, slept in the laboratory for three consecutive nights. Electroencephalograms, electrooculograms, and measurements of penile erections were recorded.The average tumescence time per night was 158.99 min; average REM time was 137.07 min. Average simultaneous REM and tumescence per night was 101.89 min. These subjects averaged 6.85 tumescence episodes/night, and, of these, 5.15 occurred during a REM period. Tumescence episodes during REM averaged 30.77 min in duration, whereas episodes which occurred when no REM was present averaged 11.75 min. All subjects had at least four REM periods per night and at least three tumescence episodes. No subject had more than 6 REM periods or more than 11 tumescence episodes.The amount of penile tumescence during a night's sleep was found to be less subject to the first night effect than was total sleep time, which indicates the strength of the underlying process controlling tumescence. Two components of NPT were described: a high probability component (maximum tumescence during REM), and a variable probability component (all nonmaximum and non-REM tumescence). Although the results indicated that there is a close relation between REM and tumescence, no simple cause and effect relation between the two phenomena was apparent.NPT seems to be a complex process with multiple functions. Although it may play a role in sexual development, it may be only partially related to the sexual activity of the mature male.SpeculationNocturnal penile tumescence in pubertal males is temporally related to the appearance of REM activity during sleep. This tumescence represents a complex process with multiple functions, one of which may be sexual development.

ISSN:0031-3998    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

ExtractCystathionase activity was absent from human fetal liver and brain as early as 6 weeks of gestation. Hepatic methionine-activating enzyme (26 ± 3 nmoles/mg protein/hr) and hepatic cystathioninesynthase (21 ± 4 nmoles/mg protein/hr) were present (cf.86 ±16 and 98 ± 19 nmoles/mg protein/hr, respectively, in mature human liver). All three activities were absent from the placenta. Human fetal liver contained higher concentrations of cystathionine (14 ± 2 $mUmoles/100 g wet weight) than mature human liver (0) and human fetal brain (4.0 ± 0.6 $mUmoles/100 g wet weight). Methionine-activating enzyme of human fetal brain, but not liver, showed a tendency to increase with development (coefficient of correlation was 0.62; 0.01 <P< 0.05).35S-l-methionine injected into the umbilical vein of six human fetuses was incorporated into free methionine in liver and brain, but not into free cyst(e)ine, homocyst(e)ine, taurine or, except for the smallest fetus, cystathionine.35S-l-cysteine similarly injected was incorporated into free cysteine in liver and brain to a greater extent than in plasma, whereas it was incorporated into cystine in plasma to a greater extent than in either liver or brain. Incorporation of35S into cystathionine in liver was greater from35S-l-cysteine than from35S-l-methionine. Both35S-l-methionine and36S-l-cysteine were actively incorporated into tissue proteins: methionine > cysteine and liver > kidney > brain.Incorporation of35S-l-methionine and35S-l-cysteine incubated with minced liver from four human fetuses showed more active incorporation of methionine (11,836–15,045 dpm/mg protein) than cysteine (7,044–9,856 dpm/mg protein).SpeculationThese studies suggest that cysteine is an essential amino acid in human fetuses and in infants for some time after birth, especially if they were born prematurely.

ISSN:0031-3998    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

ExtractWe have found a genetic trait of arginase deficiency in erythrocytes (RBC) ofMacaca fascicularis(crabeater macaque). Measurements of arginase activities and arginine concentrations in RBC, and information derived from breeding experiments indicated that arginase activities in RBC are 12.59 mmoles/g hemoglobin (Hb)/hr (range: 8.36–15.24) in normal monkeys, 4.40 mmoles/g Hb/hr (sd ± 2.37) in hetero-zygotes for this trait, and less than 0.05 mmoles/g Hb/hr in homozygotes for this trait. Concentrations of arginine in erythrocytes are less than 0.01 $mUmoles/ml packed cells in both normal and heterozygous monkeys, and 0.975 $mUmoles/ml packed cells (sd ± 0.556) in homozygous monkeys.There are no significant differences in plasma amino acids and hepatic arginase activity in any animal.SpeculationStudy of arginase activity in RBC will be expanded to include a large number of monkeys in order to determine the incidence of arginase deficiency in RBC in this species. The possibility of using these monkeys as an animal model for study of human disease arginase deficiency (e.g., genetic engineering) will be explored.

ISSN:0031-3998    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

ExtractDuring active rickets, the increase in 3′,5′-adenosine monophosphate (3′,5′-AMP) excretion after infusion of parathyroid hormone (PTH) can be claimed as a demonstration of PTH responsiveness, at least as far as the kidney is concerned (Table II). In patients with vitamin D-dependent rickets, following 25-HCC therapy, the basal excretion ratios of nanomoles 3′,5′-AMP/milligrams creatinine fall within the normal range, and, although the basal ratios of milligrams phosphate/milligrams creatinine excretion decrease to normal (Tables III, IV, and V), a phosphaturic response to PTH is still not evident. The high basal ratios of nanomoles 3′,5′-AMP/ milligrams creatinine and milligrams phosphate/milligrams creatinine suggest underlying hyperparathyroidism during a phase of this syndrome marked by hypocalcemia and hyperaminoaciduria. During 2-day PTH challenges, while rickets was active, the peak increases in serum calcium above base line were 1.92, 1.80, and 1.86 mg/100 ml. After treatment with 25-hydroxycholecalciferol (25-HCG), no further significant increases in serum calcium above base line could be elicited (Tables VI, VII, VIII). It would seem, therefore, that, while these patients were untreated, small but sufficient amounts of 25-HCC or another metabolite of vitamin D were available to permit the calcium-mobilizing action of PTH on bone. The observed hypocalcemia in vitamin D-dependent rickets, then, is most likely secondary to a defect in gastrointestinal absorption. Mineral balance studies during active rickets revealed an absorptive defect for calcium, phosphorus, and magnesium—a defect completely reversible after 25-HCC treatment.SpeculationWe suggest that the small intestine represents the prime target organ site for impaired vitamin D action in this disease by differential failure in the biologic formation of 1,25-dihydroxycholecalciferol from 25-HCC. Similarly, we postulate that a variable hydroxylating deficiency may be present in the transformation of vitamin D3to 25-HCC. Genetic heterogeneity, therefore, may ultimately explain common responses in these three patients to contrasting doses of dihydrotachysterol (DHT) and 25-HCC.

ISSN:0031-3998    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

ExtractCultured skin fibroblasts from normal individuals and patients with Hurler's syndrome were examined by electron microscopy at different phases of the culture cycle at 7, 21, and 35 days after retrypsinization and inoculation. Cultures were incubated for 0.5–24 hr with colloidal gold, incubated to localize acid phosphatase and aryl sulfatase B activities histochemically, and assayed for these enzymes biochemically. Both types of fibroblasts grew to saturation densities of 4 × 106cells/dish.The large vacuoles seen in the cytoplasm of Hurler fibroblasts appeared to be secondary lysosomes, for they accumulated particles of colloidal gold and contained myelin-like figures. They seemed to derive from the Golgi membranes which tended to show a higher frequency of dilated cisternae than those of normal cells. Specific activities of the assayed enzymes in normal and Hurler cells were equal. In normal cells, acid phosphatase was demonstrated in the same vacuoles which accumulated colloidal gold.SpeculationThe large vacuoles of Hurler fibroblasts appear to be secondary lysosomes and to derive from the Golgi apparatus rather than from the rough endoplasmic reticulum.

ISSN:0031-3998    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

ExtractKetotic hyperglycinemia is a syndrome in which elevated concentrations of glycine occur in body fluids of patients who manifest life-threatening episodes of ketoacidosis very early in life. The disorder originally described under this heading is now known to be more reliably categorized by propionic acidemia than by hyperglycinemia. Studies of the metabolism of glycine and of propionate in this condition have been undertaken. Conversion of glycine-1-14C and of propionate-1-14C to14CO2has been studied bothin vivoandin vitro.Conversion of glycine-2-14C to serine-3-14C has been studiedin vivo.It was found that the conversion of glycine-1-14C to CO2in vivowas defective in all three of the patients with ketotic hyperglycinemia. At the earliest time points, the specific activities of expired CO2in control subjects varied from 25 to more than 60 dpm/$mUmole, whereas in patients these values did not exceed 10 and were less than 5 in two patients. Conversion of the second carbon of glycine to the third carbon of serine was normal. The relative specific activity of the third carbon was 20. This value was 2–10 times the values found previously in patients with nonketotic hyperglycinemia where this conversion is defective. Conversion of propionate-1-14C to CO2was defective bothin vivoandin vitroin patients with ketotic hyperglycinemia and with methylmalonic acidemia. In control subjects, specific activities of the CO2expired following injection of propionate-1-14C approximated 200 dpm/$mUmole at the earliest time points, whereas inVBthe comparable specific activity was close to 0. Activity of propionyl-coenzyme A (CoA) carboxylase was absent in the fibroblasts of a patient with ketotic hyperglycinemia. Values of 15—30 dpm/5 mg protein obtained in the patient do not seem to differ significantly from 0, whereas in control subjects the values ranged from 985 to 2655 dpm/5 mg protein. These observations indicate that there are defects in the metabolism of both glycine and propionate in patients with ketotic hyperglycinemia.SpeculationIn propionic acidemia with ketotic hyperglycinemia there is a defect in the oxidation of both propionate and glycinein vivo.Propionate carboxylation has been demonstrated to be defectivein vitro.The abnormality of propionate metabolism seems to be primary; that of glycine metabolism may be secondary, or both could reflect a defect in synthesis of a common cofactor.

ISSN:0031-3998    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

ExtractResponse of the fetal lamb to metabolic acidosis in the absence of hypoxia or maternal acidosis was studied and compared with that of the newborn lamb. Experiments were conducted on nonanesthetized fetuses intactin utero, catheters having been implanted previously at hysterotomy. Metabolic acidosis was produced by infusion of 28 mmoles of lactic or hydrochloric acid (0.25 m) into the femoral vein of fetus or newborn.Similar changes in acid-base state were produced with hydrochloric and lactic acids. In fetuses, pH fell 0.28 pH units; this decrease was greater than that observed in newborns (0.20 pH units). Newborns hyperventilated during and following infusion, lowering Pco2by an average of 8 mm Hg and partially compensating for the metabolic acidosis. In fetuses, arterial Pco2rose during infusion by an average of 6 mm Hg, but values for Pco2in umbilical vein and maternal artery did not change. Thus fetal A-V difference for Pco2across the placenta increased, whereas the Pco2gradient between fetus and mother remained constant. These observations suggest that fetal ability to compensate for metabolic acidosis is limited by the maternal Paco2.Upon completion of the acid infusion, pH rose and base deficit fell at approximately the same rate in both fetus and newborn, but the rate of recovery was slow. After 1 hr, pH was still significantly lower than the control value (by 0.1 pH unit) and base deficit was lower by 9 mEq/liter. By 12 hr, all acid-base values had returned to normal.SpeculationThese experiments indicate that the transfer of hydrogen ion across the placenta is relatively slow, even when the circulatory status of both mother and fetus is normal, and there is no fetal hypoxia or uterine contraction. In this respect the placental membrane has properties similar to the blood brain “barrier.” With strong uterine contractions, maternal perfusion of the intervillous space is reduced or ceases, which leads to successive episodes of fetal hypoxia and acidosis. Slow placental transfer of hydrogen ion may explain the development of metabolic acidosis in the fetus during the course of labor.

ISSN:0031-3998    

出版商:OVID    

年代:1972

数据来源: OVID