Cytogenetics of fetal wastage

A consecutive series of 50 couples with a histroy of fetal wastage were studied cytogenetically with current banding technics. Fetal wastage was defined as occurring in couples who had more than two early abortions, stillbirth(s) or livebirths(s) or both of infants with multiple congenital anomalies. Three women were found to be balanced reciprocal translocation carriers; all translocations were not detectable by the conventional method but were demonstrable by current banding technics. In addition to the translocation carriers, one woman was found to be a mosaic for 45,X/46,XX/47,XXX. Four of the parents showed increased mitotic instability or chromosome breakage and rearrangement, or both. Parental chromosome abnormalities may therefore account for fetal wastage in between 6 and 16 per cent (or about one in 10) of couples having such a history. Such couples, if identified, can potentially benefit by prenatal monitoring of future pregnancies.

Sex steroid influence on triglyceride metabolism

Triglyceride metabolism was investigated in groups of fed and fasted rats after 21 days of parenteral estradiol (5 mug daily), progesterone (5 mg daily), or the two steroids in combination. Results were compared with control groups receiving an oil solvent alone. In rats given estradiol separately or combined with progesterone, hypertriglyceridemia was uniformly associated with increased plasma triglyceride entry, estimated with the i.v. Triton WR1339 technique. Progesterone alone had no effect on these parameters. Plasma postheparin lipolytic activity (PHLA), adipose, mammary gland, and protamine-resistant liporotein lipases (LPL) were significantly increased in progesterone-treated rats and significantly decreased in rats receiving estradiol with the exception of mammary gland LPL, which was also increased to a slight extent. The combined regimen reduced plasma PHLA and increased protamine-resistant adipose, and mammary gland LPL activity. Sex steroid treatments had minimal effects on plasma glucose and free fatty acid concentrations, but all increased plasma insulin significantly. Hyperinsulinemia did not parallel changes in body weight or other measured parameters. Linear regression analyses revealed that plasma triglyceride concentrations in all fed, treated rats correlated significantly with triglyceride entry but not very uniformly with plasma or tissue LPL activity. We conclude that estradiol, unlike progesterone, has substantial lipemic effects in the rat which relate best to triglyceride entry. Hyperinsulinemia, changes in body weight, plasma PHLA, and tissue LPL activities did not consistently predict the influence of sex steroid treatment on plasma triglyceride concentrations.

Balanced translocation in fetal wastage

A balanced reciprocal translocation involving the long arms of a No. 4 and a No. 11 chromosome, t(4;11) (q25;q13), was found in a mother who had one spontaneous first trimester abortion and 2 abnormal infants, as well as in her 2 phenotypically normal children. This translocation was not detectable by conventional karotyping since the two exchanged chromosome segments are almost identical in size; it was demonstrated by the new banding technic which allow us to recognize and to identify each chromosome and its segments accurately.

Familial x/x translocation: t(x;x)(p22;q13)

We have studied a family with an X/X translocation which was found in a 16-year-old daughter and in her 34-year-old mother. The daughter had short stature, secondary amenorrhea, and many Turner’s stigmata. The mother, 5-ft tall, had a few Turner’s stigmata and had developed secondary amenorrhea at age 24. Both peripheral leukocyte and skin fibroblast cultures of the daughter revealed, by conventional karyotype analysis, 46 chromosomes with one C-group chromosome missing and with an extra No. 2-like chromosome in all metaphase cells examined. By both Q- and G-banding techniques, this abnormal karyotype was identified as 46,X, + t(X;X)(p22;ql3). An identical translocation chromosome was demonstrated in the mother’s cells, but 50 % of the cells had a 45,X chromosomal constitution. Autoradiographic studies showed that the X/X translocation chromosome was the late-replicating X in all cells examined from both the daughter and the mother. The difference in the phenotypic manifestations of the daughter and of her mother can be explained perhaps by the different contents of the other active X chromosomes. When the same X chromosome is inactivated in all cells, mutations present in the active X chromosome are not compensated and therefore are expressed.

Metabolic responses to fasting and ethanol infusion in obese, diabetic subjects. Relationship to insulin deficiency

During total fasting, insulin regulates plasma glucose concentrations primarily by controlling hepatic glucose production rather than by influencing peripheral tissue glucose utilization. Administration of ethanol to individuals deprived of food lowers plasma glucose principally by suppressing hepatic gluconeogenesis. With these two observations in mind, an indirect study was made of insulin deficiency and disturbed hepatic carbohydrate metabolism with persistent hyperglycemia during total fasting in six severely diabetic obese women, matched in age and weight with six nondiabetic and six moderately diabetic, obese female subjects. The degree of abnormal hyperglycemia that distinguished the two diabetic groups from each other and from control patients during a seven day total fast were related to the degree of hypoinsulinemia. Plasma glucogenic amino acids, including alanine were significantly depressed in the severely diabetic patients throughout the fasting interval. Four hour intravenous infusions of ethanol after fasting lowered plasma glucose to the greatest extent in patients with severe diabetes and least in the nondiabetic obese. In all instances, ethanol infusion decreased plasma glucogenic amino acids. Differential sensitivities of plasma glucose responses to fasting and to ethanol administration in these patients suggest that hepatic glucose production is inappropriate in severely diabetic, obese subjects. The defect correlates with subnormal plasma glucogenic substrate concentrations, suggesting increased hepatic extraction and conversion to glucose. Hypoglycemic effects of ethanol may be induced, in part, by altered availability of plasma amino acid precursors.

Reciprocal translocation versus centric fusion between two No. 13 chromosomes. A case of 46,XX,-13,+t(13;13)(p12;q13) and a case of 46,XY,-13,+t(13;13)(p12;p12)

The centric fusion, or Robertsonian, type of translocation has been considered as a fusion of the entire long arms of two acrocentric chromosomes preceded by breakage of the centric heterochromatin. Reunion of the long arms is considered to include the centromeres, only one of which is visible by conventional staining methods. Prior to the development of the current banding techniques in human chromosome identification, the possibility that a centric fusion-like translocation might be the result of a reciprocal translocation was merely speculative. With the various banding techniques, we have identified two different types of 13/13 “centric fusion”-like translocation chromosomes with trisomy 13, i.e., one case of reciprocal translocation, 46,XX,–13,+t(13;13)(p12;q13), and one true case of centric fusion translocation, 46,XY,–13,+t(13;13)(p12;p12). In the first case, the unequal translocation of two No. 13 chromosomes was evident with the Q-and G-banding patterns; this patient also had a milder clinical manifestation of trisomy 13, since she was only partially trisomic for the long arm of No. 13. In the second case, the Q- and G-banding patterns revealed a symmetrical involvement of two No. 13 chromosomes in the translocation, and the C- and Q-banding techniques showed two distinct centromeres in the translocation chromosome. The latter patient demonstrated the typical trisomy 13 syndrome. The example of these two cases indicates that, with the current banding techniques, the true incidence of reciprocal translocations among so-called centric fusion types of translocations can be more accurately estimated.

Metabolic effects of weight loss in obese subjects. Changes in plasma substrate levels, insulin and growth hormone responses

Oral glucose tolerance and intravenous tolbutamide, glucagon and insulin tolerance were assessed in six obese patients before and after an average weight loss of eighty-five pounds and a reduction from 83 to 27 per cent above ideal body weight. Results were compared to ten nonobese subjects of similar age.

Before treatment fasting plasma glucose, free fatty acids and immunoreactive insulin exceeded normal levels. Total plasma alpha-amino acid nitrogen levels were unaffected by obesity. Post-challenge insulin responses during the first three tolerance tests were two to four-fold above control responses, and increments of immunoreactive growth hormone during insulin tolerance were subnormal in the obese. After weight reduction only minor differences in mean yjilues existed between obese and control groups.

These findings indicate that disturbances in fasting plasma substrate levels as well as plasma insulin and growth hormone responses fii obese individuals are reversible after substantial weight reduction.