[A comparison of plasma amino acid concentrations between appropriate and small for gestational age fetuses]

OBJECTIVE

To investigate the role of amino acid played in pathogenesis of small for gestational age (SGA) fetuses.

METHODS

Plasma amino acids' concentrations (PAAC) of umbilical venous samples obtained by cordocentesis before labor or at cesarean section were measured in 30 cases of appropriate for gestational age (AGA) fetuses at different gestational age. PAAC of both mother and fetuses were measured and compared in 10 cases of SGA and 10 cases of AGA.

RESULTS

In cases of AGA, the PAAC in fetuses (3.11 +/- 0.41 mmol/L) were found to be higher than that in mothers. There were significant correlations between fetal and maternal PAAC. The total PAAC in mothers and fetuses, and its ratios were not changed with gestational age. In cases of SGA, essential amino acids' concentration (EAA), especially branch chain amino acid (BCAA) and lysine, decreased significantly. The feto-maternal ratios of EAA and BCAA were reduced significantly, whereas concentrations of EAA and BCAA in mothers did not change significantly.

CONCLUSIONS

The results indicated that placental function and maternal nutrient supplement were important factors for maintaining fetal growth and development. In AGA cases, relationship of PAAC between mothers and fetuses were kept in a stable balance. In SGA fetuses certain amino acid metabolic disturbances existed. The reduction of some PAAC was not due to their decrease in mothers.

Developmental defects of the ventromedial hypothalamic nucleus and pituitary gonadotroph in the Ftz-F1 disrupted mice

Ad4BP (or SF-1) has been identified as a transcription factor which regulates all the steroidogenic P450 genes in the peripheral organs, and is encoded by the mammalian homologue of Drosophila FTZ-F1 gene. mRNA coding for Ad4BP was detected in the hypothalamus and pituitary of rats by RT-PCR. Immunohistochemical analyses using an antiserum to Ad4BP in the brain and pituitary revealed that the transcription factor is expressed in nuclei of the dorsomedial part of the ventromedial hypothalamus (dmVMH) and in some subpopulation of the adenohypophysial cells. Double immunostaining of the pituitary for Ad4BP and trophic peptide hormones, FSH, TSH, and ACTH, indicated a restricted localization of Ad4BP to the gonadotroph. Disruption of the mouse Ftz-F1 gene was clarified to induce severe defects in the organization of the dmVMH and the function of the pituitary gonadotroph. However, some of the dm VMH neurons and pituitary gonadotrophs persisted, which provided a sharp contrast to complete agenesis of the peripheral steroidogenic tissues (adrenal and gonads) in the mutant mouse. Additional abnormalities were seen in the ventrolateral part of VMH and dorsomedial hypothalamic nucleus, both of which do not express Ad4BP but have strong reciprocal fiber-connections with the dmVMH. Aromatase P450-containing cells in the medial preoptico-amygdaloid region, which were devoid of Ad4BP, persisted even in the brain of the gene disrupted mice. The present results clearly showed that the hypothalamic and pituitary Ad4BPs are essential to normal development of the functional VMH and gonadotroph through some mechanism distinct from that in the peripheral steroidogenic tissues.

Structural relationships between social support and coping

Relationships between social support and coping were examined over a one-year period in a sample (n = 120) exposed to a specific stressor (i.e. a spinal cord injury). Two issues were evaluated: (1) patterns of social support and coping over time; and (2) the direction of the effects of coping on social support or vice versa. Subjects had incurred a spinal cord injury within the preceding year, completed their rehabilitation, and returned to the community. They were assessed at 1, 4 and 12 months post-discharge to capture possible changes in patterns of social support and coping. Covariance structure modelling indicated a single-factor construct based on three measured subscales for social support (instrumental/informational/emotional), and for coping (problem-oriented/perception-oriented/emotion-oriented). While the factor structure of coping was invariant over time, the structure of social support changed from a high concentration of informational support at one month to a higher saturation of emotional support at 4 and 12 months, potentially reflecting changes in the salience of different components of the network. The perceived availability of social support was seen to have direct effects on future coping. At one month, social support had a direct positive effect on coping at four months. However, at four months social support had a negative effect on coping at 12 months, which may reflect a change in the structure of the social support construct itself. That is, as the factor structure of social support varied with time, coping may also have been influenced by differing perception of one's needs and circumstances. Thus, the study provides evidence for the dynamic effects of social support on coping, depending on one's stage in the process of long-term adjustment. The findings underscore the interplay between social support and coping, and the need for future research and practical applications to recognize temporal effects on the relationships between these two complex constructs.

Striking changes in the structure and organization of rat fetal membranes precede parturition

Premature rupture of fetal membranes can harm infant and mother. It is unclear whether structural changes predispose these membranes to breaking. We thus assessed rat visceral yolk sac placenta (VYSP) and amnion by light and by transmission electron microscopy on Days 18-21 of gestation. Light microscope sections were stained for connective tissue (extracellular matrix) components: collagen, glycoprotein, and glycosaminoglycans/proteoglycans. Some tissue was incubated with chondroitinase ABC. We observed that fetal membranes became increasingly fragile, rupturing readily on Day 21. On Days 18-20, the two epithelial layers of the capsular VYSP were separated by a well-developed, well-vascularized connective tissue layer that stained intensely for all matrix components studied; on Day 21, the connective tissue layer was thinner, moderately stained, and less vascularized. On Days 18-20, the two cellular layers of the amnion were separated by a narrow, compact connective tissue layer that stained modestly for all matrix components; on Day 21, this area was widened and stained faintly. Transmission electron microscopy showed that collagen fibrils of the amnion were abundant, closely packed, and well organized on Days 18-20, whereas on Day 21 they were few in number, widely spaced, and disorganized. Similar changes were present after incubation with chondroitinase ABC. In addition, amniotic epithelial cells were moribund and delaminating, basal laminae were deteriorating or absent, and few cells were at the outer surface of the amnion. All changes preceded parturition. We conclude that the structural integrity of rat fetal membranes is impaired before birth through the loss of connective tissue components and cells, changes that presumably underlie membrane rupture. Lastly, the similarity of structural changes in rat and human fetal membranes point to the potential usefulness of the rat model.

92-kDa gelatinase (matrix metalloproteinase-9) is induced in rat amnion immediately prior to parturition

The fetal membranes undergo striking changes in structure before delivery that involve catabolism of the extracellular matrix. To investigate the role of specific enzymes in this process, we examined gelatinase activities in rat amnion, visceral yolk sac placenta, and placenta and amniotic fluid between Days 18-21 of pregnancy. Matrix metalloproteinase (MMP)-2 was present in amnion on all days, and its activity increased slightly on Day 21. The 92-kDa gelatinase, MMP-9, was not detected on Days 18-20 but appeared by the morning of Day 21. There was a marked increase in MMP-9 mRNA in the amnion on Day 20, preceding the appearance of MMP-9 activity. Western blotting confirmed an increase in MMP-9 protein in amnion on Day 21. MMP-2 and MMP-9 activities were detected in extracts of whole yolk sac placenta, placenta, and amniotic fluid, but there were no striking changes in these gelatinases between Days 18 and 21. However, the capsular regions of the visceral yolk sac placentae, which thin and rupture during labor, did show higher MMP-9 activity on Day 21 than on Days 18 and 20. We suggest that the striking increase in MMP-9 expression in amnion and possibly the capsular region of the visceral yolk sac placenta approximately 12 h prior to delivery is responsible, in part, for the alterations in the structure of these fetal membranes before parturition.

92-kd type IV collagenase (matrix metalloproteinase-9) activity in human amniochorion increases with labor

To determine whether specific collagenolytic enzymes are expressed in human fetal membranes with labor, we examined gelatinase activity in extracts of amniochorion by zymography. The 92-kd gelatinase (MMP-9) was barely detectable in extracts of fetal membranes before the onset of labor but was readily demonstrable in extracts prepared from membranes isolated from laboring women or membranes collected immediately after delivery. In contrast, the 72-kd gelatinase (MMP-2) was detectable in extracts from pre- and post-labor membranes. Ethylenediaminetetracetic acid and the tissue inhibitor of metalloproteinases, TIMP-1, inhibited the gelatinase activities detected by zymography, confirming that the enzymes are metalloproteinase. Assay of amniochorion gelatinase activity using a radiolabeled denatured collagen substrate revealed a more than twofold increase in activity comparing pre-labor with post-labor fetal membrane extracts. A function-blocking anti-MMP-9 monoclonal antibody inhibited pre-labor membrane gelatinase activity by approximately 11.5%, which was only slightly greater inhibition than observed with irrelevant monoclonal antibodies. However, post-labor membrane gelatinase activity was reduced by 53% by the function-blocking antibody, indicating that MMP-9 is a major contributor to the increased gelatinase activity extractable from post-labor membranes. Western blot analyses demonstrated increased MMP-9 protein in amniochorion extracts after onset of labor. MMP-9 protein and mRNA were co-localized in amnion epithelium, underlying macrophages and chorion laeve trophoblast and decidual cells after labor. We conclude that 1) MMP-9 activity and protein in human amniochorion increases with labor and 2) MMP-9 is expressed by amnion epithelium, macrophages and chorion laeve trophoblast and decidual cells. The increased expression of MMP-9 may result in degradation of the extracellular matrix of the fetal membranes and facilitate their rupture under both physiological and pathological conditions.

Patterns of alcohol, cigarette, and caffeine and other drug use in two drug abusing populations

Relationships were explored among the frequencies of use of various drugs by a sample of drug-abusing clients of the Addiction Research Foundation (ARF) in Toronto and by drug abusers volunteering to participate in research at the Addiction Research Center (ARC) in Baltimore. The two groups of drug-abusing individuals differed in a number of characteristics. Those from ARF were admitted primarily for diagnosis and possible treatment for alcohol and non-opioid drug problems, whereas those from the ARC were admitted for participation in research on other drugs of abuse, primarily involving opioids. Patterns of use of certain drugs tended to covary in both groups. Of particular interest was the finding that severity of alcoholism was directly related to various measures of tobacco and caffeinated beverage use. In contrast, there was little correlation between the frequency of use among other drugs of abuse (e.g., heroin, cannabis, glue) and the use of tobacco and caffeine. These findings suggest that dependence on nicotine, caffeine, and alcohol may be governed by the same factors and possibly should be considered jointly in the treatment of alcoholic persons. Frequency of use of other drugs examined may be controlled by other factors than those which determine level of use of tobacco and caffeine.

Relationship between dietary fatty acid, selenium, and degenerative cardiomyopathy

With the finding of an increasing number of cases of degenerative cardiomyopathy (DCM) amongst patients in Chongqing, Sichuan, People's Republic of China, an attempt has been made to delineate possible etiological factors. In this province endemic for Keshan disease and with considerable consumption of oils high in erucic acid, the latter does not appear to be an operative noxious agent in DCM. Additionally, it does not appear to be caused by excessive oxygen radicals, low levels of antioxidants or low selenium levels. However, lower omega-3 fatty acid levels along with higher serum lipids may be the mechanism, via higher thromboxane levels, of the production of the myocardial degeneration seen in DCM.

Superior outcome of females over males after brief treatment for the reduction of heavy drinking

Problem drinkers (52 males, 38 females) recruited through advertisements were randomly assigned to one of three treatments:

GUIDELINES

three sessions of advice using a pamphlet outlining basic steps for achieving abstinence or moderate drinking. Manual: three sessions of instruction in the use of a 'self-help' manual presenting a step-by-step approach for attaining abstinence or moderate drinking. Therapist: six or more sessions of instruction in the methods outlined in the 'self-help' manual. At 3, 6 and 12 months follow-up, no significant differences were found among the groups in reduction of heavy drinking days (i.e. days when consumption exceeded four drinks, each containing 13.6 g/ethanol). Overall, the number of heavy days were reduced from an average of 43 at intake, to 20 over the 1-year follow-up period. Females, however, had significantly greater reductions than males (75% versus 35%). Three months after treatment the rate of successful moderate drinkers was significantly higher for females than males in the GUIDELINES (60% versus 33%) and the Manual condition (63% versus 18%), but not in the Therapist condition (25% versus 35%). At 1-year follow-up, females were more successful than males in all conditions. Mean changes in GGT and MCV levels lended support to the change in drinking status (from heavy drinker at intake to moderate drinker at follow-up), based on clients' self-reports.

An analysis of the paradoxical effect of morphine on runway speed and food consumption

A previously reported paradigm in which rats run down a runway for food reward followed by morphine injection was analyzed to assess the utility of the paradigm in studies of opiate reinforcement. One experiment replicated the original report that post-trial morphine caused both an increase in runway speed and a decrease in food consumption (taste aversion) over successive trials, and showed in addition that the increase in runway speed did not occur as a result of food deprivation alone, but required the animals to have consumed food in the goal box. A second study using the quaternary opiate antagonist methyl naltrexone to block the peripheral effects of morphine suggested that the increase in runway speed has a peripheral locus while the taste aversion has a central one. A third experiment in which morphine was microinjected into either the lateral ventricle or the ventral tegmental area supported these observations, in that intracranial morphine failed to result in an increased runway speed, but did produce taste aversion after microinjection into either site. These findings also suggest that the increase in runway speed caused by post-trial morphine in this experiment has a peripheral locus of effect, which is probably distinct from the central effect that supports morphine self-administration and conditioned place preference.

The multidimensional assessment of stressful life events

This study examined the multidimensionality of life event changes as measured by the widely used Schedule of Recent Events. A factor analysis based on 353 alcohol and drug abuse patients identified six distinct clusters: a) personal and social activities; b) work changes; c) marital problems; d) residence changes; e) family issues; and f) school changes. Significant correlations were found between the six factors and the Cornell Medical Index, measures of psychopathology, demographic characteristics, and alcohol and/or drug-related problems. Advantages of considering the six homogeneous factor scales over the Schedule of Recent Events total score were evident in higher correlations with substantively relevant variables. The six factors provided empirical support for the multidimensional assessment of life event changes. Future research should emphasize the use of multiple scale instruments that provide more specific indices of life changes.

Differential weights in life change research: useful or irrelevant?

The simple count of life event changes (SRE) and the differential weighting of these events (SRRS) were compared in a clinical sample (N = 353). Composite scores from the SRE and SRRS correlated almost perfectly at 0.97, and correlations from brief subscales (3 to 8 events) ranged from 0.93 to 0.99. Moreover, a virtually identical pattern of correlations for either composite was evident with external variables (demographic characteristics, physical symptoms, psychopathology). Under fairly general conditions, the use of differential weights in scaling life events makes little difference, since alternative schemas yield composite scores that are substantially correlated.