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Biomedical subjects

H Jackson

Publications and source records attributed to H Jackson.

At least 181 records · Page 10Linked to original sources
PubMed1976

Streptococcal control in grade schools.

Streptococcal infection has been reduced by some school-centered programs. This controlled study evaluates the relative effectiveness and cost of four different school programs: (1) Each day, throat specimens from children with sore throats were cultured. (2) Each week, all children were inspected and specimens from those with signs of pharyngitis were cultured. (3) Specimens from all students were cultured once each month. (4) Same as protocol 3, but students with positive cultures were excluded from school until they began receiving therapy. Schools using protocols 1 and 4 had substantial reduction in streptococcal prevalence. The monthly "all-student program" was most economical in terms of volunteer time, classroom interruption time, and money. The school culturing program may have contributed to a significant decline of rheumatic fever in the county during the study.

Bacteriological Techniques↗
PubMed1976

Comparative effects of niridazole on spermatogenesis and reproductive capacity in the mouse, rat and Japanese quail.

Niridazole is an effective schistosomicidal compound which, at lower dose levels, affects schistosome gonads. Its antifertility and possible mutagenic effects after various courses of oral treatment were compared in mice, rats and Japanese quail (Coturnix coturnix japonica). In all three species the meiotic stage of spermatogenesis was particularly affected. In mice the highest dose rate (five daily doses of 100 mg/kg) produced sterility during the 4th week. Rats were more susceptible, the compound producing prolonged and, in some animals, permanent sterility against which HCG treatment offered no protection. In quail only a brief phase of sterility occurred. Niridazole appears to be non-mutagenic since dominant lethal mutations were not produced in dose-response studies. Minimal changes in testis histology occurred in the mouse, but in rats severe damage persisted even in animals which had recovered their fertility.

Animals↗
PubMed1975

Antibodies to spermatozoa. VI. Comparative studies of sperm-agglutinating activity in groups of infertile and fertile women.

In order to evaluate the significance of sperm antibodies in relation to infertility, studies have been made on both infertile and fertile populations. The infertile population consisted of about 150 couples with long-standing infertility, predominantly of the unexplained type. The fertile population consisted of 78 antepartum women and 35 postpartum women. In all these individuals, sperm antibody was sought by two methods of serum testing, namely, the Kibrick (K-B-M) and the F-D methods of sperm agglutination. In the infertile group, the Kibrich test was positive for 23.1 per cent of the women and 9.6 per cent of the men, whereas the F-D test was positive in 16.4 per cent of the women and 5.0 per cent of the men. In contrast to these values, it was found in the fertile group that the Kibrick test was positive in 2.7 per cent of these women and the F-D test was also positive in 2.7 per cent of them. A number of technical details and precautions have also been emphasized. These principles are intended to minimize the occurence of nonspecific and false-positive results.

Agglutination Tests↗
PubMed1975

Parthenogenic development after chemical treatment of Xenopus laevis spermatozoa.

Eggs of Xenopus laevis were fertilized in vitro by spermatozoa pre-treated with various concentrations of aziridinyl urea (ethyleneurea) for between 30 and 120 minutes. At 2 and 4 mg/ml for 30 minutes there was a high incidence of abnormal embryos, few of which developed into tadpoles; after 6 and 8 mg/ml no tadpoles were produced. However, the highest concentration 10 mg/ml, yielded 66% of tadpoles, only 7% of which were obviously abnormal. With increasing time the same pattern of events was obtained except for a displacement towards the lower concentration ranges. Tadpoles developing from these latter experiments were found to be haploid. The results resemble those obtained by exposure of Rana pipiens spermatozoa to X-rays and ultraviolet light, with the production of gynogenetic embryos, usually referred to as the Hertwig effect.

Animals↗
PubMed1975

Congenital absence of a pedicle in a cervical vertebra.

The importance of agenesis of a pedicle lies in its resemblance to a destructive lesion of the pedicle or to an expanding lesion in an intervertebral foramen. The correct diagnosis can be made roentgenologically by demonstrating a widened intervertebral foramen at the level of an absent pedicle with posterior displacement of the maldeveloped lateral mass. Two cases of agenesis of a pedicle in a cervical vertebra are presented.

Cervical Vertebrae↗