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Biomedical subjects

J McGrath

Publications and source records attributed to J McGrath.

140 records · Page 8Linked to original sources
PubMed1980

Sterility in mutant (tLx/tLy) male mice. III. In vitro fertilization.

Mice which are heterozygous for two complementary lethal t mutations (t6/tw32) exhibit complete male sterility. Experiments have been conducted to determine if spermatozoa from these heterozygous males can fertilize oviducal ova in vitro. The experiments have been designed so that specific barriers which are present during in vivo fertilization can be sequentially removed and the fertilizing ability of the spermatozoa tested after each barrier is eliminated. Our results show that spermatozoa from t6/tw32 males are unable to effect fertilization even after all of the barriers normally imposed by the female reproductive tract have been removed.

Animals↗
PubMed1980

The in vitro transmission frequency of the t12 mutation in the mouse.

Male mice which are heterozygous for a recessive lethal mutation (+/tL) transmit the tL mutation in non-Mendelian ratios. In the present studies, spermatozoa obtained from +/t12 males were used to fertilize ova from +/t12 females in vitro. The frequency of transmission of the t12 mutation determined from these in vitro studies was compared with the frequency of transmission of this mutation in normal and delayed matings. The data show that the transmission frequency of the t12 mutation, in vitro, is Mendelian and is the same as the transmission frequency of the t12 mutation in vivo when matings are delayed until the time of ovulation.

Animals↗
PubMedDate not supplied

Maternal Thp lethality in the mouse is a nuclear, not cytoplasmic, defect.

The Thp mutation, an allele of the mouse T/t complex, differs from other known mutations in that its effects are determined by the sex of the parent from which it is inherited; when inherited from the female parent, it is invariably lethal at the embryonic stage, but, most embryos which inherit the mutation from the male parent survive. Thus most heterozygous embryos carrying the maternally derived mutation die in the second half of pregnancy, while the exceptional embryos surviving to parturition give oedematous, cyanotic individuals that die within 24 h. The lethal maternal effect of Thp may be transmitted either through the cytoplasm of the ovum (oogenic defect) or through the female pronucleus (embryogenic defect). Here we have sought to decide between these possibilities by performing reciprocal nuclear transplantations between one-cell embryos from Thp/+ and +/+ females. Our observation that this maternally inherited lethal effect of Thp persists when Thp/+ pronuclei are transplanted into +/+ cytoplasm suggests that the defect responsible for the pattern of inheritance lies in the pronuclei and not the cytoplasm.

Alleles↗
PubMedDate not supplied

The prognostic value of the tumor marker CA 15-3 at initial diagnosis of patients with breast cancer.

CA 15-3 has been most widely used as a serum tumor marker in follow-up and detection of breast cancer recurrence. In this study we have specifically focused upon the prognostic implications and utility of preoperative CA 15-3 levels. We have identified on our database 414 patients with breast cancer in whom serial levels of the serum tumor marker CA 15-3 had been determined at diagnosis and follow-up. We have analyzed the follow-up and clinical outcomes in these patients and from this data we have assessed the potential of CA 15-3 as a predictor of five-year overall and disease-free survival. Our results show that an initially elevated CA 15-3 level is associated with a very poor prognosis in both early and late stage disease. Elevated pre-biopsy CA 15-3 levels are associated with 14% five-year disease-free survival rates and 17% overall survival rates at five years. In contrast, normal CA 15-3 levels are associated with 47% five-year disease-free survival rates and 54% overall survival rates at five years (p<0.01). Comparison of five-year survival rates between patients with elevated and normal CA 15-3 levels in early breast cancer (stage I and II) also showed significant differences, with survival being 41% and 75%, respectively (p<0.01).

Breast Neoplasms↗
PubMedDate not supplied

Mass media approaches to reducing cardiovascular disease risk.

A key function of a basic and clinical biomedical research organization is to communicate the findings of clinical investigations so that people may apply the results to improve their health and well-being. To help communicate results from cardiovascular disease research, the National Heart, Lung, and Blood Institute has established a series of national health education programs. The authors describe a model for two of the five programs and discuss the role of communication media in supporting national goals for education programs. The research basis for the programs is reviewed, together with the process by which the Institute develops information materials for mass media, notably public service announcements. A description of two national health education campaigns, hypertension and cholesterol, illustrates how market research is used to identify appropriate target audiences, develop messages, and select channels of communication. Lessons learned about the role of mass media in a national health education campaign are summarized.

Cardiovascular Diseases↗