摘要:

This study examined spontaneous respiratory rate and variability as a function of age and sleep state in eight normal full-term infants. Each infant was admitted at 5:00 PM to the sleep laboratory for 12-hr monitoring sessions during the first week of life and at 1, 2, 3, 4, and 6 months of age. Both sleep and cardiopulmonary variables were recorded. A Beckman pCO2monitor sampled expired gas through a miniature cannula taped under the infant's nostrils. Peaks and troughs of breaths were measured by a computer peak sensing program. Median respiratory rates and interquartile ranges of breath intervals for each minute were determined. Each minute was coded as quiet sleep (QS), active sleep (AS), waking (AW), and indeterminate state (IN). Respiratory rates and variability were highest during the first week of life. They declined during the next 2 months and began to level out at 3 months of age (Table 3).The state-relationship was not homogeneous at all ages. Respiratory rates and variability during wakefulness were always higher than those during sleep states. The strongest relation between respiration and sleep states was found between birth and 3 months of age. QS values were uniformly low, and those of AS and IN minutes were intermediate between AW and QS.SpeculationRespiration rates and variability decreased linearly between birth and three months of age. The differences between the developmental course of respiratory rates and variability between 1 and 3 months reported here and cardiac rates and variability previously reported in the same infants suggest a difference in the central nervous system modulation of these systems.

ISSN:0031-3998    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

Optimal conditions are described for measurement of cystathionase activity in long term lymphoid cell lines. In 21 control lines established from normal subjects, cystathionase (EC 4.4.1.1) specific activity was 25.8 ± 1.7 (mean ± SE) nmole cysteine/hr/mg protein. Extracts of three lymphoid lines (NB-36, NB-95, and NB-77) established from three vitamin B6-responsive patients with primary cystathioninuria had activity of 3.6–7.3; from a B6-unresponsive patient (NB-68) had no detectable activity; from five obligate heterozygotes for cystathioninuria had activity of 11.2–18.9.Two, or possibly three, different modifications of the cystathionase molecule could be demonstrated in cultured cells from the patients with primary cystathioninuria, based on the effects of added pyridoxal phosphate (PLP) in the enzyme assay, on the extent of reaction with rabbit antihuman hepatic cystathionase, and on the ability to compete with normal lymphoid cell line enzyme extract for the antibody combining sites. When PLP is not added to the assay system, the normal enzyme extract still had 89% of its activity in 1.0 mM PLP; on agar double diffusion analysis it gave a band of identity with normal human hepatic cystathionase; the precipitin band had cystathionase activity, but inhibition by antibody could be shown in solution. Lymphoid line extract from the B6-unresponsive patient had no detectable activity in the absence or presence of PLP, did not form a precipitin band, and did not compete with normal enzyme extract for the antibody combining sites. Thus, synthesis of apocystathionase is absent or significantly reduced; alternatively, the protein produced has lost its antigenic determinants

ISSN:0031-3998    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

Oxygen equilibrium curves of partially autoxidized adult (HbA) and fetal hemoglobins (HbF) were determined at 2–75% methemoglobin (met-Hb). Hemoglobin concentration of 5 mM, pH 7.15 (Tris 0.05 M), and temperature of 37° corresponded to intraerythrocytic in vivo conditions. With increasing met-Hb fractions the curves became shifted to the left and approached a hyperbolic form: P50of both HbA and HbF decreased in absence of 2, 3-diphosphoglycerate (2, 3-DPG) from about 13 to 7 Torr, and Hill's n from 2.7 to 1.25. Independent of the met-Hb fraction the alkaline Bohr effect was increased by 2, 3-DPG. The allosteric effect of 2, 3-DPG on P50decreased with increasing met-Hb. At all oxidation levels this effect was smaller on HbF than on HbA: At 50% met-Hb P50of HbF is increased by 0.7 Torr/mM 2, 3-DPG increase, P50of HbA by 1.3 Torr, respectively. There was no evidence of preferential autoxidation of α or non-α chains of the hemoglobin molecule.Oxidized hemoglobin does not take part in oxygen transport. In addition a left-shifted, more hyperbolic curve means restricted oxygen unloading from the remaining active hemoglobin. Thus, from application of our results to clinical conditions it must be concluded that sustained methemoglobinemia, despite partial compensation by 2, 3-DPG, may interfere with oxygen supply to tissue, particularly in the perinatal period, when HbF prevails.SpeculationTissue oxygen supply, as calculated from the present data on O2capacity, P50, 2, 3-DPG reactivity, Hill's n, and Bohr factors, appears to be markedly lowered in methemoglobinemia, particularly in presence of fetal hemoglobin. Reduced tissue oxygen supply in the perinatal period, in addition to a generalized cytochrome b5reductase deficiency (22), might contribute to irreversable cerebral dysfunction in hereditary methemoglobinemia.

ISSN:0031-3998    

出版商:OVID    

年代:1978

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

In order to evaluate the role of leuteinizing hormone releasing hormone (LHRH) and gonadotropins in the control of secretion of Müllerian inhibiting substance, groups of pregnant rats were injected intraperitoneally with high potency antiserum from a rabbit immunized with LHRH. Pregnant females were injected at 13 and 20 days of gestation with LHRH antiserum or an equal volume of normal rabbit serum as a control. The testes and penis were reduced in weight and size in 6-day-old pups of the experimental group indicating the luteinizing hormone (LH) was blocked and that LHRH antiserum was active. Testicular fragments of 17-day fetuses and 6-day-old pups showed an increase relative to controls in Müllerian inhibiting substance activity in a graded organ culture bioassay system. These studies suggest that secretion of Müllerian inhibiting substance is curtailed by one or both gonadotropins.SpeculationThe secretion of Müllerian inhibiting substance is under inhibitory gonadotropin control, dependent on normal hypothalamic secretion of LHRH.

ISSN:0031-3998    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

A study of peripheral blood lymphocyte populations in 27 children with Hodgkin's disease (HD) and 13 age-matched control subjects is presented. The absolute numbers and percentages of T and B lymphocytes identified by their surface marker characteristics were determined. In addition, in 13 HD children the percentages of T and B lymphocytes were estimated in the spleens removed at staging laparotomy. No differences were observed between the total peripheral blood lymphocyte counts of HD and control children, and we found no evidence of progressive lymphopenia with advancing stages of the disease. No decrease in the numbers of peripheral blood T lymphocytes was seen in this group of HD children. In contrast, the proportions and absolute numbers of B lymphocytes tended to be significantly lower in the children with HD than in the control subjects. In 9 of the 13 spleens studied high percentages of T lymphocytes were seen; low percentages of B lymphocytes were found in all spleens examined.SpeculationThe results are discussed in the light of the hypothesis that in HD an anomaly of the spleen environment is present at the early stages of the disease which results in sequestration of circulating T lymphocytes, and that this anomaly is closely related to the basic pathogenesis of the disease.

ISSN:0031-3998    

出版商:OVID    

年代:1978

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1978

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1978

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1978

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1978

数据来源: OVID