摘要:

The effects of sex chromosome constitution and estrogen treatment on increase in height and on skeletal and sexual maturation were studied in 116 patients with female phenotype and at least one major feature of Turner's syndrome associated with an abnormality of an X chromosome. Seventy-one patients had a pure 45X karyotype (XO group) and the remainder comprised 33 with X chromosome mosaicism and 12 with a structurally abnormal X (non-XO group).Birth weight at all durations of gestation was similar for XO and non-XO but significantly lower than normal. Correlations of birth weight with adult height and weight were unexpectedly high, 0.96 and 0.92 respectively. Patients were significantly shorter than normal (P< 0.05) at all ages tested from 2–17 years, but increasingly more so after age 10. Mean adult height was 142.0 ± 7.60 cm (n= 28). Unlike most other reports there was no consistent pattern of significant differences in height between XO and non-XO or between Xp monosomic and Xp disomic patients.The 13 patients (2 XO, 11 non-XO) who experienced spontaneous menarche evidenced a slight premenarcheal growth spurt. In 11 of these 13 patients, the average growth rate increased from 3.00–4.83 cm/year in the year before menarche; however, this is far below the mean pubertal growth velocity of 9 ± 1.03 cm/year. This observation indicates that endocrine mechanisms associated with more normal pubertal sexual development also produce a more normal pattern of growth. The estrogen-treated group grew at a lower, fairly constant rate in the 2 years before and 1 year after treatment, and total increase in height after estrogen treatment averaged only 3.6 cm.Rate of skeletal maturation was less than normal (0.53 bone-age year/chronologic year) in the 2 years before treatment, and greater than normal (1.47 bone-age year/chronologic year) in the two years after treatment, suggesting that these patients may be hypersensitive to the skeletal maturing effects of estrogen.Pretreatment breast development: absent or more delayed than pubic hair development, but the delay in both secondary sex characters was greater than the delay in skeletal maturation. At age 12, the average normal girl has moderate breast development, but at bone-age 12, only 5.4% of our patients had moderate breast development and only 10.8% had moderate pubic hair.Significantly but not unexpectedly more. non-XO than XO patients experienced spontaneous menarche. Even the non-XO patients who require estrogen treatment may have a more normal level of ovarian function than do XO patients, who have significantly less pretreatment breast development and later epiphyseal fusion.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

The distribution and localization of iodocompounds reaching the brain during early development were measured in rat pups nurtured on [1251]-containing milk from dams receiving. daily [125I-iodide injections. The regimen produced no measurable changes in growth and development of the offspring during the nursing period. Pup brains accumulated labeled iodocompounds at a faster rate than they grew and accumulated protein. The ratio of [125I]-iodocompounds in cerebrum relative to skeletal muscle increased progressively from day 11 through day 19. Significant differences in distribution of radioactivity in different brain regions were evident on day 1; developmental progress was associated with significantly different rates of regional accumulation of the isotope. On day 1 only 10% of the radioactivity in the postnuclear supernatant phase of brain homogenates was particle-bound; at the time of weaning, radioactivity in-brain particles accounted for more than 50%. Growing nerve cell processes and myelin, known to be major targets of early thyroid hormone deficiency or excess, were also the major subcellular sites of [125I-iodocompound localization in the developing rat brain. Overall, the ontogeny reflected progressive elaboration of iodocompound-processing neural systems resembling those recently recognized in adult brain.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Mammary amylase is a possible alternate pathway of digestion of glucose polymers and starches, that is most important in early infancy when pancreatic amylase is low or absent in duodenal fluid and responds poorly to stimuli. Human breast milk contains 1000–5000 units of amylase/liter. In order to evaluate the likelihood that a significant proportion of mammary amylase activity would withstand passage through the stomach, purified and unpurified mammary anylase were exposed to acid and pepsinin vitroto simulate the gastric environment found in young infants. Both purified and unpurified enzymes were stable at pH 7.5 with little or no activity lost after 4 h, and approximately 80% retained at 6 h. When incubated at pH 3.5, one-third of unpurified enzyme activity was retained for 6 h; in contrast, the purified enzyme was acid labile losing 80% by 2 h. Addition of bovine serum albumin or breast milk proteins to purified enzyme protected the activity. When unpurified enzyme was exposed to a stepwise decline in pH from 6.5 to 3.5 over 4 h, 50% of the original activity was retained. Unless the concentration was >3750 units/ml, the addition of varying concentrations of pepsin to defatted breast milk incubated at pH 3.5 did not affect any greater decay of enzyme activity despite evidence of peptic digestion of proteins in the reaction mixture. This study supports the possibility that ingested mammary amylase could retain a significant proportion of its original activity after exposure to acid and pepsin in the stomach of young infants.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

A 17-month-old girl, with acute intermittent ataxia and drowsiness, had hypertyrosinemia (serum tyrosine, 62 μmole/dl) and phenolic aciduria in the absence of hepatic, renal, eye or skin lesions. Serum methionine and urinary >-aminotevulinic acid concentrations were normal. Her psychomotor development was also normal. Protein restriction and vitamin C therapy failed to correct the biochemical abnormality. Liver biopsy was histologically normal.Analysis of the enzymes in the fiver biopsy, taken at 25 months of age, showed no detectable activity of 4-hydroxypbenylpyruvate dioxygenase (4HPPD), either in whole homogenate or cytosol fraction. Mixing experiments revealed no inhibitor of either 4HPPD or tyrosine aminotransferase (TAT).TAT in unfractionated liver was 0.23 μmole/mg protein/h (control, 0.10–0.30 μmole/mg protein/h;n= 5). In mitochondria, TAT was 0.24 μmole/mg protein/h (control, 0.09–0.12 μmole/mg protein/h;n= 3) whereas in cytosol fraction it was 0.23 μmole/mg protein/h (control, 0.27–0.44 μmole/mg protein/h;n= 3). Glutamate dehydrogenase activity appeared in the cytosol fraction suggesting some rupture of mitochondria during fractionation of the patient's liver and indicating that true cytosol TAT might be somewhat lower than indicated; however, the kinetics of the patient's cytosol TAT were normal: Km for tyrosine, 4.5 X 10-3M (control, 4.0 x 10-3M); Km for α-ketoglutarate, 98 x 10-6M (control, 75 X 10-6M); approxhnate Km for pyridoxal phosphate, 2.1 X 10-6M (control, 4.0 X 10-6M). Vmax in patient liver was 0.37 μmole/mg protein/h (control, 0.88 μmole/mg protein/h). These data argue against a primary abnormality of TAT but are consistent with a defect of 4HPPD; thus, this patient appears to represent a previously undescribed form of tyrosinemia.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Tracheae, bronchi, nasal epithelial, and nasal polyp tissue slices were incubated in tissue culture with [3H]-glucosamine, and the rate of secretion of labeled mucus glycoproteins was measured. Secretion rates were at least 3− to 6-fold higher for all of the samples from nine patients with cystic fibrosis (CF) who were studied, as compared with values for tissue slices from eight young subjects not affected with this disease. The secreted glycoproteins were further purified into one neutral and three acidic fractions by ion-exchange chromatography on DEAE-cellulose. The glycoproteins secreted by respiratory epithelial tissue from cystic fibrosis subjects contained relatively more of two acidic glycoprotein fractions. Double-label experiments with both [3H]-glucosamine and [35S]-sulfate as mucus glycoprotein precursors further substantiated the shift to more acidic components in the purified mucus glycoproteins and, in addition, suggested a higher level of sulfation of these same two acidic glycoprotein fractions. All four of the labeled glycoprotein fractions secreted by cultured human bronchi cochromatographed with authentic mucus glycoproteins purified from sputum of cystic fibrosis subjects by the same techniques. The differences between mucus glycoproteins from cultured CF airway tissue and mucus glycoproteins from other patients' tissue included relatively increased rates of production, level of sulfation, and greater acidity. Further applications of thesein vitrotechniques should allow the determination of the enzymatic and biochemical causes of these observed differences in the absence of such potentially confounding variables as concurrent airway infection or of oropharyngeal secretions.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

The purpose of this study was to examine the influence of neonatal age, sex, type of feeding, and rapid eye movements on the occurrence of apneic pauses during sleep in a hyperthermic environment. One hundred and twenty fullterm infants (equally divided by sex and type of feeding) were observed during a complete nap within the first and approximately fourth wk of life. Each sleep session was characterized by twenty-one measures including the longest apneic pause, mean apnea duration, relative frequency of apnea, apnea periodicity, respiratory rate, and relative frequency of REM epochs. The relative frequency of REM epochs decreased with age and was greater in formula-fed (versusbreast-fed) infants.The longest apneic pauses were greater in the first wk of life and in breast-fed infants. In addition, the average Longest Duration: REM ∼ was ∼ greater ∼ than ∼ the ∼ average ∼ Longest Duration:NREM. Of potential importance was the demonstration that this latter effect was greater in the first wk than in the fourth wk of life. Breast-fed infants and females had larger apnea Mean Duration scores. The relative freqquecy of apneic pauses (>2 sec in duration), periodicity, and the relative amount of apnea were greater in the fourth-wk study and in breast-fed infants. The relative frequency of apneic pauses >6 sec in duration (Apnea6%) and the A6/D% measure were greater in breast-fed infants. Numerous interactions were observed between age, sex, and type of feeding. Respiratory rate decreased with age and was greater during NREM epochs and in formula-fed infants.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Proline uptake and metabolism has been examined in newborn Sprague-Dawley rat kidney and compared to that in adult animals. |14C|-Proline uptake by renal tubule fragments from newborn rats occurs at the same initial rate as in adult tubules, but at physiologic concentrations achieves significantly higher intracellular levels after 15 min of incubation. Considerable metabolism of the proline taken up was observed in tissue of both ages. Analysis of acid soluble and insoluble tubule fractions from newborn and adults indicates similar degrees of proline incorporation into protein and oxidation to CO2relative to the amount of radioactivity taken up. A major difference exists, however, with respect to the labeled components of the acid extract: adult tubules convert |14C|-proline to metabolites at a rate twice that of newborn. Analysis of concentration-dependent uptake data reveals two distinct entry systems for proline in both isolated newborn and adult tubules. No difference in the Km or Vmax was found between the young and mature tubules.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Serum alpha-fetoprotein (AFP) concentrations were measured in dried blood spots and the biologic half-life of AFP was determined during the first month after parturition. AFP Mood levels, in babies at all birthweight groups during the first wk, were partitioned according to birthweight and sex. A synthetic surge of serum AFP at postnatal day 3 was observed in babies of the low birthweight category (8 Ib 8 oz), categories. All babies weighing less than 6 Ib 8 oz, regardless of prematurity likewise displayed the synthetic surge. The sex of the infant appeared to have no influence on AFP serum concentrations. In a population of infants ranging in age from 1–30 days, the biologic apparent half-life of AFP was calculated as 5.7 days; however, the half-life of AFP was found to differ among the three groups of infants when subdivided by birthweight and was higher (7.7 days) in babies of low birthweight. Our determination of 2 S.D. cutoff values for AFP in the first wk of life should prompt further studies in which the relationship of AFP to newborn disorders should be more fully explored.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Acute glucagon injections were performed in chronically catfa-eterized fetal lambs in late gestation to assess the fetal metabolic response to exogenous glucagon infusion. Glucagon dosages between 1 ug/kg and 1 mg/kg induced significant fetal hyperglycemia by 15–30 min postinjection, with peak glucose values 130–180% of control. Increasing responsivity to the same dose/kg was noted to parallel increasing gestational age. In selected preparations in which umbilical venous catheters were implanted, glucagon injection caused an acute fail in the glucose/oxygen quotient and net umbilical glucose consumption. The fall in glucose consumption to 8% of control values occurred within 15 min of injection and suggests acute fetal glucose excretion, probably secondary to hepatic ghycogenorysis. Glucagon injection in the neonatal lamb caused qualitatively similar increases in plasma glucose concentration but the quantitative responses were considerably greater. No change in fetal β-hydroxybntyrate (β-OHB) concentration was noted after injection; nor did the fetal uptake or excretion of this ketone change. The neonatal β-OHB concentration was significantly different (P< 0.001) from fetal concentrations and did rise 14% above control after glucagon injection; thus, elevation of plasma glucagon in the fetus causes an acute hyperglycemia but, unlike the adult, does not induce a significant ketogenesis.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID