Leydig cell mitoses in human testes bearing early germ cell tumors

Summary Numerous mitoses were noted in testicular tissue from adult men with early germ cell tumors. More than 15 Leydig cells undergoing mitosis were found in the interstitial compartment. The presence of specific crystalline intracytoplasmatic inclusions demonstrated for the first time that differentiated Leydig cells are capable of proliferation. Occasionally cells are difficult to discriminate during mitosis. To establish reference criteria, the light- and electron-microscopic features of the following mitotic cells were examined: Leydig cells, fibroblasts, perivascular cells, peritubular cells, and lymphocytes. Supplementary mitoses in germ cell tumors and in a case of Leydig cell tumor were investigated. In the literature, only single reports of mitoses in Leydig cells are available. The frequent incidence of Leydig cell mitosis in early germ cell tumors may be due to the presence of growth-promoting factors in the testicular tissue.     

Complete sequence of the coding region of human elongation factor 2 (EF-2) by enzymatic amplification of cDNA from human ovarian granulosa cells

The use of two primers allowed the specific enzymatic amplification of elongation factor 2 starting with total double-stranded cDNA from human ovarian granulosa cells. The amplified DNA fragment with a length of 1765 bp was restricted and sequenced by the shot gun approach. From the sequences obtained from the amplified fragment and the cDNA insert of pHGR81 [Rapp et al. (1988) Biol. Chem. Hoppe-Seyler 369, 247-250] respectively, the DNA sequence containing the complete coding as well as the 3'-untranslated region was assembled.     

Stimulation of progesterone secretion by cultured human granulosa cells with melatonin and catecholamines

Granulosa cells, aspirated from the follicles of patients undergoing treatment for in-vitro fertilization, were cultured in serum-supplemented medium. Adrenaline and noradrenaline stimulated a dose-related increase in progesterone secretion with a maximum stimulation at 10(-5) M, a response that was prevented by the beta-antagonist, propranolol. Adrenaline and hCG showed similar characteristics in their stimulation of progesterone secretion but there was no further increase in progesterone when the 2 compounds were added together. Melatonin stimulated progesterone secretion and, like adrenaline, this stimulation was prevented by propranolol. The ability of both adrenaline and melatonin to increase progesterone secretion was dependent on the degree of follicular development, as determined by peripheral oestradiol concentrations, on the day of laparoscopy. These results suggest that adrenaline and melatonin may have a physiological role in modulating luteal function and that melatonin may act by a beta-adrenergic-related mechanism.     

Value of routine ultrasound scanning at 19 weeks: a four year study of 8849 deliveries.

OBJECTIVE--To evaluate the effectiveness of routine ultrasound scanning at 19 weeks'' gestation in an unselected population in terms of accuracy of detection of fetal structural abnormality and the effect on obstetric and neonatal care. DESIGN--Prospective study over four years. Scans performed by radiographers with overall supervision by a radiologist. SETTING--Ultrasound department of district general hospital. SUBJECTS--All pregnant women were offered scans; 8523 of 8849 (96%) accepted. MAIN OUTCOME MEASURES--Information obtained from hospital records, genetic analysis, and post-mortem findings. RESULTS--166 fetal anomalies occurred; 140 were detected at 19 weeks (sensitivity 85%; specificity 99.9%). In 27 cases fetuses were shown to have severely crippling or lethal abnormalities; termination of pregnancy was requested in 25. Early diagnosis influenced timing and place of delivery in babies with severe cardiac or gastrointestinal anomalies. CONCLUSION--Scanning at 19 weeks with availability of termination can reduce perinatal morbidity and mortality. Scanning can be performed in a general ultrasound department with adequate counselling facilities and close cooperation between radiographers, midwives, obstetricians, paediatricians, and the radiologist.     

No evidence for linkage of autosomal dominant proximal spinal muscular atrophies to chromosome 5q markers

Summary Two recent articles have reported the linkage of a gene for recessive spinal muscular atrophy (SMA) on the chromosome region 5q11.2–13.3. Our data show no linkage of the dominantly inherited forms of SMA to this chromosome region.     

Synthesis patterns of a set of follicle cell proteins in Drosophila melanogaster sibling species

The protein synthesis pattern of a set of stage and tissue specific proteins has previously been described in Drosophila melanogaster. The analysis of this set of follicle cell proteins (Fc proteins) is here extended to cover several sibling species of Drosophila melanogaster, namely D. simulans, D. mauritiana, D. erecta and D. yakuba. Even though a similar set of proteins were synthesized in these species, minor differences in size of the proteins were found between the species. Some of the species exhibited variation within species.     

Melatonin directly stimulates the secretion of progesterone by human and bovine granulosa cells in vitro

Melatonin, at concentrations and periods of exposure reflecting those present during the circadian cycle, was investigated for its influence on steroid production by granulosa cells cultured in serum-supplemented medium. At high (200 pg/ml) but not low (20 pg/ml) physiological concentrations, melatonin significantly stimulated progesterone production by human granulosa cells. This response was independent of the overall level of cell activity and was seen under the different culture conditions associated with different culture media. Exposure to melatonin for 8 h significantly stimulated progesterone secretion to a level similar to that achieved under continuous exposure, and the effect was reduced to control levels during subsequent periods in which no melatonin was added. Melatonin had no consistent effect on aromatase activity in the conversion of stored or serum-available androgen to oestradiol. Melatonin significantly stimulated progesterone production by bovine granulosa cells in vitro, at concentrations similar to those present during the endogenous nocturnal rise (100-400 pg/ml). This response to physiological conditions by human and bovine cells suggests a role for melatonin in the regulation of progesterone production by the ovary.     

Chain length-dependent association of distamycin-type oligopeptides with A·T and G·C pairs in polydeoxynucleotide duplexes

Different binding affinities of various distamycin analogs including the deformylated derivative with poly(dA-dC)·poly(dG-dT) were investigated using CD measurements. The inhibitory effect of distamycins on the DNAase I cleavage activity of DNA duplexes strongly supports the binding data. The base specificity of the ligand interaction with duplex DNA depends on the chain length of distamycin analogs. Netropsin, distamycin-2 and the deformylated distamycin-3 show no binding to dG·dC containing sequences at moderate ionic strength and are classified as highly dA·dT specific. In contrast distamycin having three, four or five methylpyrrolecarboxamide groups also forms more or less stable complexes with dG·dC-containing duplexes. These ligands possess a lower basepair specificity. The correlation between binding behavior and oligopeptide structure shows that presence of the number of hydrogen acceptor and donor sites determines the basepair and sequence specificity. The additional interaction with dG·dC pairs becomes essential when the number of hydrogen acceptor sites exceeds n = 3.     

THE INFLUENCE OF PRECURSOR POOL SIZE ON MITOCHONDRIAL COMPOSITION IN NEUROSPORA CRASSA

The chemical composition of mitochondria obtained from exponentially growing Neurospora can be varied by addition of choline or amino acids to the culture medium. The variation affects the phospholipid to protein ratio, and the density of mitochondria as determined by isopycnic centrifugation in sucrose gradients. These variations have been observed in biochemical mutant strains as well as wild type cultures. In a choline-requiring strain, two levels of choline supplementation to the medium have been defined: a low choline concentration just adequate to support maximal logarithmic growth, and a high choline concentration which permits maximal incorporation of radioactive choline into cellular lipids. Mitochondria isolated from cultures growing at the low choline concentration have one-half the phospholipid to protein ratio of those from high choline cultures, and their density is significantly higher. Artificial mixtures of the two types of mitochondria can be resolved into two populations by isopycnic centrifugation. The concentration of cytochromes (measured by mitochondrial difference spectra) and of malate and succinate dehydrogenases (measured by enzyme activity) were the same in both types of mitochondria, on a protein basis. The results suggest that during growth of the mitochondrial mass, the incorporation of phospholipid and protein components can vary independently. Direct kinetic measurements did indeed show that choline, added to a culture growing at low choline concentration, was incorporated into mitochondrial lipids at a rate faster than the incorporation of protein. The mitochondrial phospholipid to protein ratio can also be influenced by the level of leucine supplementation to a leucine-requiring mutant, so that with leucine concentrations above those required for maximal exponential growth, mitochondria of increasing density and decreasing phospholipid to protein ratio are produced. Additions of choline or amino acids to the minimal medium of wild type cultures influence mitochondrial composition in a manner directly comparable to that observed in biochemical mutant strains. The results suggest that mitochondrial composition, in general, is determined by rates of incorporation of the two major components, phospholipid and protein; that these rates can vary independently in response to precursor concentration in the culture medium; and that they normally operate at a precursor (substrate) concentration below saturation level.