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Biomedical subjects

C Hobbs

Publications and source records attributed to C Hobbs.

9 recordsLinked to original sources

Expression of mutant p53 gene in squamous carcinoma arising in patients with recessive dystrophic epidermolysis bullosa.

Epidermolysis bullosa, a rare genodermatosis, is characterized by increased skin fragility manifest as blistering and sometimes accompanied by scarring. The latter is particularly severe in the recessive dystrophic variant and may be complicated by the development of squamous carcinoma in up to 30% of patients. We have studied 23 such tumours in six patients with this variant, with an anti-serum to p53 protein. Twenty-six per cent of the squamous carcinomas labelled positively for mutant-type p53 protein. This low figure, however, reflects the large number of well-differentiated tumours in this series, where 14 out of 15 were negative. In the moderate to poorly differentiated examples the positivity rate was 63%. Of the three patients in the latter category, one has died from disseminated tumour and another has widespread metastases. The findings support the hypothesis that mutant p53 protein expression correlates with poorer tumour differentiation. They also suggest a possible correlation between p53 protein expression and tumour behaviour.

Carcinoma, Squamous Cell

Menarcheal age in Ghanaian school girls.

In a cross-sectional retrospective study of 2087 Ghanaian school girls in various educational institutions in the Kumasi district, Ashanti region, Ghana, the mean menarcheal age was found to be 13.98 +/- 1.42 years. Differences in the menarcheal age of the girls was found to be significantly correlated to social class, parents ethnic origin, educational institution and home living area (P = 0.0001). The duration of the menarche and the interval between the menarche and the second period was found to be influenced by the age at menarche (P less than 0.01). Decline in menarcheal age in concurrence with world trends was observed. Further studies are necessary to identify the inherent and specific factors in the Ghanaian population which relate to and influence the age of menarche.

Adolescent

The relation of the true conjugate to maternal height and obstetric performance in Ghanaians.

The true conjugate was determined intraoperatively with a caliper in 114 Ghanaian women and was correlated with their height, obstetric performance and fetal dimensions. Those patients undergoing cesarean section for cephalopelvic disproportion (Group Ia) were found to have a significantly shorter mean true conjugate (9.54 cm +/- 0.63 S.D.) and mean body height (152.68 cm +/- 5.46 S.D.) and a smaller true conjugate - fetal biparietal diameter difference (10.93 mm) than those who had no cephalopelvic disproportion (Group Ib) and whose mean measurements were 10.61 cm +/- 0.81 S.D., 157.20 cm +/- 5.69 S.D. and 21.50 mm, respectively (P = 0.0001). Recommendations for appropriate referral of rural clinic patients and for selection of patients for repeat cesarean sections are based on the above findings.

Birth Weight

Cancer downwind from sour gas refineries: the perception and the reality of an epidemic.

A rural population in southwestern Alberta, Canada, living downwind from natural gas refineries, has expressed concerns about an excess of adverse health outcomes over the last 25 years. This has escalated to the point of causing a prominent sociopolitical controversy within the province. As part of a large field epidemiologic study undertaken during the summer of 1985 to investigate possible health effects, a residential cohort study was carried out to study cancer incidence. The cohort was defined as all those individuals who resided in the area in 1970. A total of 30,175 person-years of risk within Alberta were experienced by this cohort from 1970 to 1984. The incident cancers during this period were enumerated by computerized record linkage with the Alberta Cancer Registry. Age- and sex-standardized incidence ratios, based on expected rates from three prespecified demographically similar, nonmetropolitan Southern Alberta populations, were 1.05, 1.09, and 1.03, respectively, none of which was significantly different from unity. Although they do not address the issue of etiologic association, these data can provide considerable reassurance to a community that was convinced it had experienced an epidemic of cancer.

Acid Rain

A structural basis for variegating position effects.

Variegating position effects in Drosophila result from chromosome rearrangements where normal genes, having been placed next to heterochromatin, are inactivated in some cells but not in others, thereby producing a variegated tissue. We have determined that the euchromatic breakpoints for three variegating white mutants are clustered and lie approximately 25 kb downstream of the white structural gene. In each case the white locus is adjoined in the heterochromatin to a mobile genetic element. Satellite sequences are not involved. We also demonstrate that revertants of the variegating mutant, wm4, are reinversions that leave the initial wm4-heterochromatic junction intact so that some heterochromatin-derived sequences remain joined to white at its new location. These results suggest a simple model for understanding the structure of heterochromatic domains and how variegating position effects may arise.

Animals

A study of mortality near sour gas refineries in southwest Alberta: an epidemic unrevealed.

Concerns about excesses in a wide array of adverse health outcomes have been expressed for over 25 years by a rural population in southwestern Alberta, living downwind from natural gas refineries. Among these has been the perception that deaths have occurred more frequently than ought to have been expected. As part of a large field epidemiologic study undertaken during the summer of 1985 to investigate possible health effects in this area, a residential cohort study was carried out to study mortality. The cohort was defined as all those individuals who resided in the area in 1970. A total of 30,175 person-years of risk within Alberta were experienced by this cohort during 1970-84. The deaths during this period were enumerated by resident reports and by manual record linkage with the death records of the Alberta Bureau of Vital Statistics. Age- and sex-standardized mortality ratios, based on expected rates from 2 pre-specified demographically similar, non-metropolitan Southern Alberta populations, were 0.88 and 0.84 respectively, neither of which was significantly different from unity. These data cannot address the question of etiology but they can do much to allay the anxieties of a community convinced it had experienced an epidemic of death.

Adult