摘要:

In Krabbe's disease (globoid cell leukodystrophy), galactosylsphingosine (psychosine) is considered to be a causative agent of the pathology found in the nervous system of the patients. In our study, we examined the cytotoxic effect of psychosine in neural cell cultures derived from the rat nervous system. The concentration of toxic thresholds varied from cell type to cell type. The 50% of toxic doses for oligodendrocytes, astrocytes, and the sensory neurons of the dorsal root ganglia were 8, 20, and 30 µg/mL, respectively. Oligodendrocytes, therefore, appeared to show a higher sensitivity to psychosine than did astrocytes or neurons. When phorbol ester or DMSO was applied simultaneously with psychosine as protective agents in enriched cultures of rat oligodendrocytes, the total number of live cells and galactocerebroside-positive cells and the 2'3'-cyclic nucleotide 3'-phosphohydrolase activity in these cultures were considerably higher as compared with their levels in the experimental cultures treated with psychosine alone. These results indicate that phorbol ester and DMSO could serve as protective agents for psychosine neurotoxicity.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The concentrations of hypoxanthine, xanthine, and uric acid in plasma and cerebrospinal fluid (CSF), as well as the urinary output of hypoxanthine and xanthine, were measured in four groups of pigs (three groups with different degrees of hypoxemia and one control group). During hypoxemia with arterial O2tension between 2.1 and 3.0 kPa [group 1, fractional inspired oxygen (FiO2)=0.08], hypoxanthine increased in CSF from a mean basal value of 18.1 to 39.3 µmol/L at death (p < 0.02), in plasma from 25.4 to 103.6 µmol/L (p < 0.05), and in urine from 21.3 to 87.1 nmol/kg/min (p < 0.02). Xanthine changed in a similar way: in CSF from 4.0 to 10.6 /nmol/L (p<0.02), in plasma from 0.7 to 48.1 µmol/L (p<0.02), and in urine from 4.0 to 12.6 nmol/kg/min (p<0.05). Uric acid increased in CSF from 2.7 to 11.6 µmoI/L (p <0.05), and in plasma from 15.4 to 125.0 µmol/L (p<0.02). During hypoxemia with arterial O2tension between 3.0 and 4.0 kPa (group 2, FiO2=0.11), hypoxanthine increased in the CSF from 14.7 to 42.9 µmol/L (p<0.02). Plasma hypoxanthine increased from 20.3 to a maximum of 44.1 µmol/ L (p<0.02), but decreased to initial values by the time of death. The urinary excretion of hypoxanthine increased from 13 to 54 nmol/kg/min (p<0.02). Xanthine increased in the CSF from 3.9 to 13.3µmol/L (p< 0.02), in plasma from 0.6 to 36.6 µmol/L (p <0.02), and in urine from 6 to 25 nmol/kg/min (p < 0.02). Uric acid increased in CSF from 3.1 to 16.3 jumol/L (p< 0.02), and in plasma from 15.3 to 208 µmol/L (p<0.0 0.02). During milder hypoxemia with arterial O2tension between 4.3 and 5.6 kPa (group 3, FiO2=0.14), or in the control group (group 4, FiO2K=0.21), neither of the metabolites changed significantly.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

In the vitreous humor from three hypoxemic and one control group of pigs, hypoxanthine, xanthine, and uric acid concentrations were measured. The purine concentrations were measured before the hypoxemia, at the time of death, and 24 h post-mortem. During hypoxemia with arterial O2tension between 2.1 and 3.0 kPa [fractional inspired oxygen (FiO2) = 0.08] hypoxanthine concentrations increased from a mean basal value of 11.7 ± 5.6 µmol/L to 16.3 ± 2.4 µmol//L at the time of death (NS). Xanthine concentrations changed from a basal value of 0.3 ± 0.1 µmol/L to 0.6 ± 0.2 µmol/L (p < 0.02), and uric acid changed from 3.4 ± 1.1 µmol/L to 5.0 ± 4.5 µmol/L (NS). During hypoxemia with arterial O2tension between 3.0 and 4.0 kPa (FiO2= 0.11), hypoxanthine increased in the vitreous humor from a mean basal value of 9.1 µmol/L to 20.3 µmol/L at the time of death (p < 0.02). Xanthine concentrations increased from 0.3 µmol/L to 1.3 µmol/L (p < 0.05), whereas there was no change in uric acid concentration (basal 5.0 < 0.8 µmol/L and final 4.5 ± 1.0 µmol/L). During milder hypoxemia with arterial O2tension between 4.3 and 5.6 kPa (FiO2=0.14), or in the control group (FiO2 = 0.21), neither of the metabolites changed significantly. The vitreous humor was not stable postmortem, inasmuch as the mean concentration of hypoxanthine increased from 18.2 ± 7.7 µmol/L to 121.6 ± 57.4 µmol/L 24 h post-mortem (p < 0.01). In the same period, xanthine increased from a mean 0.9 ± 0.6 µmol/L to a mean 4.9 ± 5.2 µmol/L ( p <0.01).

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Retinal function was assessed by electroretinogram in 32 neonates randomly assigned to formulas of different ω-3 fatty acid content and in 10 infants fed human milk. All neonates had a birth weight of 1000-1500 g and were fed study diets from d 10 to 45 or discharge. Group A received formula containing predominantly 18:2 ω-6. Group B received a balanced mix of 18:2 ω-6 and 18:3 ω- 3. Group C was given a formula containing both essential fatty acids and supplemented with marine oil to provide 22:6 ω-3 content similar to that of human milk. The fatty acid composition of plasma and red blood cell (RBC) lipids were similar for all groups on entry but marked dietinduced differences were found after feeding the study diets. Group C was comparable to the human milk-fed group, but group A had lower 22:6 ω-3 and w-3 long-chain polyunsaturated fatty acids (LCPUFA) in plasma and RBC membranes. Cone function was not affected by dietary essential fatty acids. Rod electroretinogram thresholds were significantly higher for group A relative to the human milk-fed group and group C and significantly correlated with RBC w-3 LCPUFA (r = -0.63, p < 0.0001); 44% of the variance could be explained by RBC and plasma w-3 LCPUFA content. Rod electroretinogram amplitude was significantly lower for group A relative to the human milkfed group and group C and related to plasma 22:6 w-3 (r = 0.55) and total w-3 LCPUFA (r = 0.58) (both p < 0.0001); 42% of the variance was explained by plasma w- 3 LCPUFA, the ratio of ω-6/ω-3 LCPUFA in RBC, and gestational age at birth. Our results support an essential role for ω-3 fatty acids in retinal development.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

It has been suggested that hypercalcitoninemia may contribute to neonatal hypocalcemia in infants of diabetic mothers (IDM). Because the role of calcitonin (CT) in Ca metabolism in humans is questionable, we hypothesized that serum CT peaks similarly after birth in IDM and controls and that serum Ca concentrations do not correlate with serum CT. Forty-seven term IDM (White classes B-RT) were compared with 31 controls. Controls were born after normal pregnancies, labors, and deliveries. Blood samples (cord and 24 h) were analyzed for Ca, Mg, parathyroid hormone (PTH), and CT. Repeated measures analysis showed increasing serum Mg, PTH, and CT, and decreasing Ca over time. The incidence of hypocalcemia was significantly higher in the diabetic group (p < 0.01) and the incidence of hypomagnesemia was borderline significantly higher (p < 0.06). There were no differences in cord or 24-h serum concentrations of CT between groups. In multiple regression analysis, serum Ca and PTH were correlated (p < 0.02, R2= 0.33), but not serum Ca and CT; the increase in serum PTH in relation to serum Ca at the nadir (24 h) correlated directly with serum Mg concentrations (R2= 0.31, p < 0.05). Thus, serum CT increases after birth irrespective of the rate of decrease of serum Ca in both IDM and controls; high CT concentrations observed after birth (as compared with adult norms) do not seem to play a role in the pathogenesis of neonatal hypocalcemia in IDM; and responsiveness of parathyroid gland at birth is adversely affected by hypomagnesemia, which supports the theory of functional hypoparathyroidism in Mg deficiency.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

We measured neonatal apo A-I and apo B by ELISA, and apo(a) by RIA, in capillary blood spotted onto filter paper in samples also used for routine neonatal screening in 1032 consecutively born babies. In the 2- to 5-d-oId babies with birth weights >2.0 kg (n = 919), mean ± SD levels of apo A-I and B were 0.48 ± 0.19 g/L and 0.24 ± 0.14 g/L of whole blood, respectively. The apo A-I levels were affected by birth weight (negatively) and by age at sampling (positively). The apo B levels were affected positively by both variables, and girls had higher levels than boys (p < 0.01). These variables accounted for 3.5 and 6.2% of apo A-I and apo B variability, respectively (p < 0.001). The apo(a) levels (mean ± SD, 20 ± 23 U/L; median, 14 U/L, n = 1032) were unaffected by these factors. After adjustment for these variables, apo A-I levels were nearly normally distributed, whereas those of apo B were still positively skewed. The apo(a) distribution was strongly positively skewed and 1.2% of babies had levels above the equivalent of 25 mg/dL of lipoprotein(a) in serum. Our study shows that blood spots can be used to estimate apo A-I, apo B, and apo(a) levels in neonates, and establishes normal ranges. The results suggest that the apo(a) gene is expressed during the 1st postnatal week and that levels are independent of birth weight and apo A-I and B concentrations. They also define the effects of birth weight and age at sampling on neonatal apo A-I and B levels.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Breast milk contains an amylase that may contribute to carbohydrate digestion in infants. The aim of our study was to determine whether mothers differ in their breast-milk amylase activity and whether the activity is maintained during prolonged lactation. This was investigated by measuring breast-milk amylase activity by hydrolysis of maltotetraose in 63 English mothers of parity 1-5 and 107 Gambian mothers of parity 1-12 who were at various stages of lactation (0.5-27 mo). Amylase was present in all samples and showed a great range of activity from 0.08 to 3.53 IU/mL. Amylase activities did not vary during a feed nor over 24 h, and each mother had a characteristic level of activity in her milk. Amylase activity was higher in the 1st trimester of lactation, and decreased by 35% (p < 0.001) to a plateau at 6-27 mo. Gambian mothers of very high parity (parity 11-12) had 54% of the activity of primiparous mothers (p < 0.001), after adjustment for stage of lactation. Using community data on milk volume, the estimated breast-milk amylase intake by breast-fed children was on the order of 800-1000 IU/24 h in the 1st trimester and 400 IU/24 h in the 2nd year of lactation. Individual measurements emphasized the great differences in this intake among children of the same age. Our study showed that breast milk is an important source of amylase both in developed and developing countries, but there are large variations in intake among children.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

We examined the prevalence of human papillomavirus (HPV) infection, and associated risk factors for infection with HPV types 6,11,16,18, 31, 33, and 35, in 661 sexually active adolescent females attending family planning clinics. Fifteen percent were positive for HPV DNA by RNA-DNA dot-blot hybridization. More than 60% of the HPV-positive subjects harbored at least one of the following cancer-related HPV types: 16, 18, 31, 33, or 35. Those with HPV had a mean range of four to 10 lifetime sexual partners compared with a mean range of one to three in those without HPV (p < 0.001). After the analysis was adjusted for number of lifetime sexual partners, no other risk factor was associated with HPV infection. We conclude that oncogenic-related HPV types are common sexually transmitted organisms found in our population. The strong relationship with number of sexual partners suggests that acquisition of HPV infection is predominantly influenced by sexual behavior. However, in our population, confounders such as oral contraceptive use, past history of Chlamydia trachomatis infection, or substance abuse were not found to be significant independent risk factors.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The hypothalamic-pituitary-ovarian hormone secretion patterns were evaluated in two women with 45,X Turner syndrome, spontaneous sexual development, and monthly menstrual periods. Each woman had serum gonadotropin and sex steroid determinations during two or more menstrual cycles. During the follicular phase of a menstrual cycle, both women received 100 µg gonadotropin-releasing hormone (GnRH) s.c., and serum LH and FSH responses were determined. In addition, one woman collected daily overnight urine specimens for 40 consecutive days, spanning two menstrual periods, for the measurement of LH, FSH, estriol, and free progesterone. The randomly measured hormone results showed low serum progesterone concentrations during luteal phases, consistent with the interpretation of anovulation or inadequate corpus luteum function. At the time of the GnRH stimulation tests, baseline serum FSH concentrations and FSH responses to GnRH were within normal limits, whereas baseline LH levels and LH responses to GnRH were low. The pituitary gonadotropin secretion patterns were more consistent with patterns seen during early puberty than in the perimenopausal state. This interpretation was further confirmed by the urinary excretion patterns of gonadotropins, which were not significantly elevated. Furthermore, the urinary hormone profiles revealed that, although the intermenstrual period was of normal length, the follicular phase was prolonged, with normal levels of LH, FSH, and estriol excreted. The menstrual cycle studied was ovulatory but had a short luteal phase. The hormone results indicated that the dysgenetic ovary of women with 45,X Turner syndrome is capable of producing sufficient quantities of sex steroids and other regulatory factors to maintain gonadotropin secretion patterns that are reminiscent of early puberty. Some of the menstrual periods may be anovulatory, whereas others exhibit prolongation of the follicular phase, presumably due to difficulty in follicle recruitment, and short luteal phase due to inability to maintain normal corpus luteum function.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID