Methylation patterns of repetitive DNA sequences in germ cells of Mus musculus

The major and the minor satellite sequences of Mus musculus were undermethylated in both sperm and oocyte DNAs relative to the amount of undermethylation observed in adult somatic tissue DNA. This hypomethylation was specific for satellite sequences in sperm DNA. Dispersed repetitive and low copy sequences show a high degree of methylation in sperm DNA; however, a dispersed repetitive sequence was undermethylated in oocyte DNA. This finding suggests a difference in the amount of total genomic DNA methylation between sperm and oocyte DNA. The methylation levels of the minor satellite sequences did not change during spermiogenesis, and were not associated with the onset of meiosis or a specific stage in sperm development.

Cell lineage-specific undermethylation of mouse repetitive DNA

Several distinct cell lineages are established during mouse embryogenesis. The trophectoderm and primitive endoderm give rise to extraembryonic structures alone, while the primitive ectoderm becomes the fetus proper. Recent studies suggest that the levels of DNA modification are lower in inactive X chromosomes from extraembryonic tissues than in embryonic and adult somatic tissues. Using HpaII/MspI isoschizomers, Southern blots and cloned probes, we show here that repetitive DNA sequences from all derivatives of the two extraembryonic lineages, trophectoderm and primitive endoderm, are substantially undermethylated compared with primitive ectoderm derivatives. This contrasts with the highly methylated state of these repetitive elements observed in adult somatic tissues. Specific demethylation or inhibition of de novo methylation, or a combination of both mechanisms, may be involved. These findings suggest that elements of gene regulation dependent on DNA modification may be different in extraembryonic cell lineages.

Chronoepidemiological search for circannual changes in the sexual activity of human males

Indirect evidence of circannual (about 1-year) rhythms in the sexual activity of human males was examined utilizing the data of reported rapes in Paris, France, for 1972-78, and Houston, Texas, for 1974-75. In addition, data were available for nearly a 10-year span from Houston, Texas, as the monthly detections of the sexually transmitted diseases (STD) of syphilis and gonorrhea. The results of conventional and cosinor techniques revealed circannual rhythms in the occurrence of rape in both Paris and Houston. With regard to the former sample of 836 reported rapes, cosinor analysis revealed a circannual 0 of July 1, with the 95% CI extending from June 10 to July 20. For Houston, based upon a sample of 1,133 reported rapes, the circannual 0 occurred slightly later, around September 1, with the 95% CI extending from August 15 to September 15. Even though the overall yearly totals of reported rape differed by 4-fold between the 2 cities, the A of the circannual rhythms when expressed relative to the respective M were nearly identical, being 21.6% for Paris and 21.4% for Houston. The data on STD (3,024 cases of primary syphilis and 179,064 cases of gonorrhea), when analyzed by cosinor analysis, also revealed circannual rhythmicity. For gonorrhea, a circannual 0 of October 5, with the 95% CI from July 6 to September 4, was found; for primary syphilis the circannual 0 was somewhat delayed, occurring on November 11, with the 95% CI between October 10 and December 3. These findings, considered together with the reported observations by others of circannual rhythms in plasma testosterone and sexual activity in males as well as the sales of over-the-counter contraceptives, etc., imply that man may be regarded as a seasonal breeder, becoming more sexually active when the photoperiod becomes reduced, i.e. in the autumn. These observations provide new insight into the (chrono)epidemiology of rape and STD.

Patterns of reported rape in a tri-ethnic population: Houston, Texas, 1974--1975

Police records of reported rape, compiled for the Federal Bureau of Investigation Uniform Crime Reports, in Houston, Texas for 1974 and 1975, were analyzed in relation to ethnicity and age of victim/offender, and time and place of occurrence. Blacks had the highest race-specific rates for both victims and offenders; the majority of all rapes were intraracial. The high-risk age group for both victims and offenders was from 20 to 24 years. Rapes increased slightly during the summer months, peaked during the hours of darkness, and were fairly evenly distributed among the days of the week. The weekend calculated as from 4:00 pm Friday to 8:00 am Monday accounted for 43.6 per cent of all rape occurrences. The majority of rape events involved the use of a lethal weapon and took place in a residence.

A computer system for cytology in a private laboratory using a PDP 8/E minicomputer

A computer software package written in Dibol for a PDP 8/E computer is described that is designed for the needs of the cytology department of a moderate-sized private medical laboratory. Computerized accessioning of cases, report preparation and printing, historical filing, activity summary reports, and direct patient and physician billing are provided by the relatively inexpensive system. The software has been in use for over two years in our cytology department and has resulted in increased efficiency, cost-effectiveness, and quality of reports.

A computerized word-processing and data system for histology in a private medical laboratory

This report describes the use of a word-processing micro-computer, the Lanier Text Editor, for preparation of surgical tissue reports. Gross and microscopic description formats are stored on floppy disks, which may easily be completed and edited on a cathode-ray tube (CRT) for rapid computerized printing. Also described is the use of a PDP 8/E mini-computer for entry, storage, and manipulation of historic, demographic and diagnostic data, printing of numeric and alphabetic listings, cross-indexing of cases by diagnosis, and the accumulation of data for direct patient or physician billing.

The selection of antibiotics

The usefulness of an antibiotic depends not only upon its antibacterial potency and spectrum but also on the prevalence of resistant organisms and the extent and severity of the adverse reactions to which it may give rise. Variations in formulation of the same compound are reflected in differences in bioavailability. These may be intentional, as in the development of long-acting preparations, but may also be unexpected following differences in drug purity, content and gastro-intestinal absorption. Individual and species differences in treated animals also result in variations in bioavailability. The merits of combination products of two or more antibiotics are often equivocal and some combinations are definitely disadvantageous. Practical rules for the selection and use of antibiotics emphasise the need for full doses of effective compounds used for limited periods with monitoring of patterns of sensitivity so that problems of large-scale resistance can be avoided.

Plasma levels following administration of sodium meclofenamate by various routes

Sodium meclofenamate, an anti-inflammatory and anti-anaphylactic agent, was administered to cattle intravenously, orally and by intraruminal injection. Plasma levels of the free drug were estimated fluorimetrically at intervals after administration by each route. Levels fell rapidly, particularly during the first hour after intravenous injection. Differences between those plasma levels resulting from oral administration and those following intraruminal injection indicated that direct passage into the abomasum was achieved by the former method. Simultaneous intravenous and intrauminal injections achieved immediate high plasma levels and maintained levels adequate for efficacy for 24 h.

Prophylaxis and treatment of experimental anaphylaxis in cattle by sodium meclofenamate

Sodium meclofenamate was compared to saline for efficacy in preventing and treating experimentally induced, acute, systemic anaphylaxis in cattle. Respiratroy changes were shown to be reduced to the greatest extent. Lacrimation and collapse were not affected. The timing and routes of administration giving maximum efficacy were those which gave maximum plasma levels of the drug closest to the time of exposure of the animal to the specific antigen.

Metabolism and excretion of promazine by the horse

The urinary excretion of promazine and its metabolites has been examined in five horses, by ultraviolet spectrometry and thin-layer chromatography. In each horse, excretion continued for at least 96 h although the amount excreted was low, being about 11% of the dose. No correlation of excretion and pH or urinary volume was observed. Glucuronic acid conjugates predominated, their ratio to unconjugated metabolites being about 5:1. Promazine was found only in small amounts and traces of unconjugated sulphide metabolites were found in only one horse. At least nine metabolites of promazine were detected, the major one being the glucuronide of 3-hydroxypromazine.