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Biomedical subjects

J Clark

Publications and source records attributed to J Clark.

At least 307 records · Page 17Linked to original sources
PubMed1990

Application of linked DNA markers to screening families with multiple endocrine neoplasia type 2A.

There now exists a set of tightly linked markers to the gene causing multiple endocrine neoplasia type 2A. In this report we discuss the use of these markers for early and accurate prediction of gene carrier status in three different families. Factors that influence the probability of obtaining useful information with DNA markers are available family size, in particular the number of available affected individuals, and the extent of clinical and biochemical screening in the family. At present, DNA analysis has about a 3% risk of misdiagnosis; this risk is even lower if it is used in conjunction with the pentagastrin stimulation test for C-cell hyperplasia. With the combined tests, an individual at age 20 years may be scored as carrier or not with an estimated accuracy of 99%.

Adolescent↗
PubMed1990

Mutation of the p53 gene in human soft tissue sarcomas: association with abnormalities of the RB1 gene.

Soft tissue sarcomas have been examined for alterations in the p53 gene. In six sarcomas, loss or rearrangement of both alleles of this gene was detected while in a further seven sarcomas, point mutation or absence of transcription of the p53 gene was observed. Abnormalities of the p53 gene were found in several classes of soft tissue sarcoma, including leiomyosarcomas, rhabdomyosarcomas and malignant fibrous histiocytomas. Our studies also show that abnormalities of the RB1 suppressor gene and of the p53 gene frequently occur together. These results are consistent with the idea that the p53 gene is a tumour suppressor gene and indicate that coincident inactivation of more than one tumour suppressor gene may, in some cases, be required for tumour development.

Base Sequence↗
PubMed1990

Characterization of uterine cytosol and nuclear sex steroid receptors in aging female ICR mice.

Changes in uterine wet weight and estrogen receptor levels were studied in aging female ovariectomized ICR mice. A marked increase in uterine wet weight was observed in 18-month-old mice after injection of estradiol-17 beta (E2), from 67.6 +/- 3.1 mg (control, no injection) to 98.2 +/- 14.8 mg (1 h after injection of 1.0 microgram E2) and to 125.2 +/- 15.8 mg (4 h after injection of 1.0 microgram E2). The response to E2 in old mice was greater than that in young. This observation suggests that the uteri of old mice are still sensitive to gonadal steroids up to the post-reproductive age of 18 months. A 2.7-fold age-related increase in uterine estrogen receptor content was also noted in aging ovariectomized female mice, from 0.38 pmol/uterus in young mice to 1.01 pmol/uterus in old mice (1 h after injection of E2). Both cytoplasmic estrogen receptor content and receptor concentration (expressed as estrogen binding sites/cell) increased with advancing age. In contrast, no age-related change in the dissociation constant of estrogen receptors was detected (Kd = 1.0 +/- 0.5 x 10(-9) mol/L). The progesterone receptor content also increased with advancing age. This study demonstrates a marked increase of uterine estrogen receptor content in aging mice, suggesting that the uterus is not responsible for the increased incidence of pregnancy failure in old mice.

Aging↗
PubMed1990

The relationship of the glenohumeral joint capsule to the rotator cuff.

The glenohumeral joint capsules of 23 shoulders in which the rotator cuff was not torn were studied by gross dissection and histologic methods. The cuff tendons were resected, leaving the intact capsule attached to the bones. This dissection method provided a unique overview of the capsule in situ and allowed the areas of cuff tendon and muscle attachment to be mapped. The capsule was found to be a continuous cylinder between humerus and glenoid. On approximately one-third of the capsule (the portion adjacent to the humeral tuberosities), tight insertions of cuff tendons were noted. The superior segment between subscapularis and supraspinatus contained the coracohumeral ligament. This segment appeared to reinforce the cuff through a transversely oriented band similar to the glenohumeral ligaments.

Aged↗
PubMed1990

Comprehensive adolescent fertility project in urban Jamaica.

Each of the more than dozen countries within the English-speaking Caribbean is now experimenting with developing both traditional and new approaches to reach youth in maternal and child health and family planning programmes. They focus on education, counselling and medical services for youth.

Adolescent↗
PubMed1989

A colleague with a drink problem.

Treating a fellow GP is difficult enough, but when a colleague may have an alcohol problem your attitudes to that and your duty to the patients and profession may complicate matters. Furthermore, the mode of treatment that you choose may affect your colleague's professional standing.

Alcoholism↗
PubMed1989

Linked markers flanking the gene for multiple endocrine neoplasia type 2A.

The inherited cancer syndrome multiple endocrine neoplasia type 2A (MEN2A) has recently been mapped to chromosome 10. We have typed 29 families with this disorder with DNA markers from the pericentromeric region of chromosome 10. Two markers, RBP3 and MCK2, were tightly linked to the MEN2A gene at recombination fractions of less than 3%. Multipoint analysis of the linkage data suggests that the gene is located within a 3-cM interval defined by the markers RBP3/MCK2 on one side and TB14.34 on the other. No evidence for locus heterogeneity was detected in any of the 27 families from 14 countries who were informative for the markers tested. The data confirm and refine the original assignment and provide the basis for presymptomatic screening for this disorder.

Chromosome Mapping↗
PubMed1989

Vulvovaginitis and cervicitis.

Measures designed to reduce the incidence of cervicitis are those that make transmission of any STD less likely. Consistent and proper use of contraception, especially condoms, should be encouraged. Patients with a history of cervicitis or other STDs should be targeted for being at high risk and should have periodic screening tests to search for pathogens such as N. gonorrhoeae and C. trachomatis, even at times when they are asymptomatic. Other groups, including patients with multiple sexual partners, those with genitourinary symptoms, pregnant adolescents, and some adolescent clinic populations, also should be considered at increased risk and be monitored similarly. To be effective, encounters with adolescents around matters related to sexuality and STD must be done privately and with confidentiality assured. Special attention should be paid to the adolescent's family and cultural milieu, as well as to their level of psychosocial development, so that specific needs, fears, and misconceptions can be addressed. Cervicitis and other STDs are so common and have such important personal and public health implications that identification and effective treatment are of critical importance. The general tendency to be parsimonious when fitting together signs and symptoms into a medical diagnosis must be modified when dealing with STDs as multiple concomitant infections do occur routinely.

Adolescent↗
PubMed1989

Effects of itraconazole on mitogen stimulated human mononuclear leucocytes.

Lymphocyte transformation responses of unstimulated and mitogen-stimulated cells from normal subjects were measured in vitro in the presence of itraconazole, at therapeutic and at much higher concentrations. No differences in response from those of control cell cultures were detected at any concentration.

Antifungal Agents↗
PubMed1989

Characterisation of monoclonal antibodies for detection of Mobiluncus spp. in genital specimens.

Monoclonal antibodies were raised to the anaerobic curved rods, Mobiluncus curtisii subsp. curtisii NCTC 11656, M. curtisii subsp. holmesii NCTC 11657 and M. mulieris NCTC 11658. Three antibodies reacted with the two subspecies of M. curtisii and, when used in combination against clinical isolates, showed 100% sensitivity and specificity in immunofluorescence studies. Immunoblotting showed that two of these antibodies reacted with an epitope on a protein which had an electrophoretic mobility corresponding to a Mr of 75 Kda in the absence of a reducing agent and 82 Kda in its presence in both type strains and in clinical isolates. The third antibody reacted with an epitope in type strains which had a mobility corresponding to 75 Kda and was unaffected by a reducing agent. However, in clinical isolates the epitope was present on a protein of 75 Kda or 71 Kda, or on both. A fourth antibody showed reactivity with M. mulieris NCTC 11658 alone, but only 6 (24%) of 25 clinical isolates gave positive results by immunofluorescence. The epitope is believed to be present on a protein of greater than 90 Kda. All four antibodies were shown by immunogold staining to be directed against epitopes exposed on the cell surface.

Antibodies, Bacterial↗
PubMed1989

Clinical evaluation of the bond between composite resin and etched glass ionomer cement.

One hundred and thirty-eight non-undercut Class V abrasion lesions were restored using glass ionomer cement overlaid by composite resin. Four techniques were used: enamel and glass ionomer acid-etched, enamel only acid-etched, ionomer only acid-etched, and neither enamel nor glass ionomer acid-etched. The restorations were examined after six months, one year and two years and evaluated for integrity and marginal staining, the latter employing a direct clinical method and a set of photographic standards. The relative failure of restorations at six months was maintained at subsequent time intervals, and at two years the failure incidence was 10, 35, 43 and 58 per cent for the above four techniques respectively. Marginal staining was most evident around those restorations for which only the glass ionomer had been etched. The results indicate that the retention of composite to etched glass ionomer is similar to that of composite to dentine using many dentine bonding agents. The several advantages of glass ionomers over dentine bonding agents are discussed.

Acid Etching, Dental↗