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Biomedical subjects

T Jordan

Publications and source records attributed to T Jordan.

At least 37 records · Page 2Linked to original sources

Mutations at the PAX6 locus are found in heterogeneous anterior segment malformations including Peters' anomaly.

Mutation or deletion of the PAX6 gene underlies many cases of aniridia. Three lines of evidence now converge to implicate PAX6 more widely in anterior segment malformations including Peters' anomaly. First, a child with Peters' anomaly is deleted for one copy of PAX6. Second, affected members of a family with dominantly inherited anterior segment malformations, including Peters' anomaly are heterozygous for an R26G mutation in the PAX6 paired box. Third, a proportion of Sey/+ Smalleye mice, heterozygous for a nonsense mutation in murine Pax-6, have an ocular phenotype resembling Peters' anomaly. We therefore propose that a variety of anterior segment anomalies may be associated with PAX6 mutations.

Amino Acid Sequence↗

The human PAX6 gene is mutated in two patients with aniridia.

Aniridia is an inherited ocular disorder of variable expressivity characterized by iris hypoplasia. A candidate aniridia gene, AN, which is the human homologue of the mouse Pax-6 gene, has recently been isolated by positional cloning from the WAGR region of 11p13. Here we describe mutations in this gene in two cases of sporadic aniridia, one detected at the DNA level and one at the RNA level, both of which are predicted to affect protein function. Mutations in Pax-6 have been described previously in Small eye, the proposed mouse model for aniridia. We present new phenotypic evidence for the validity of this mouse model.

Animals↗

Positional cloning and characterization of a paired box- and homeobox-containing gene from the aniridia region.

Based on the map location of the aniridia (AN) locus in human chromosomal band 11p13, we have cloned a candidate AN cDNA (D11S812E) that is completely or partially deleted in two patients with AN. The less than 70 kb smallest region of overlap between the two deletions encompasses the 3' coding region of the cDNA. This cDNA, which spans over 50 kb of genomic DNA, detects a 2.7 kb message specifically within all tissues affected in AN. The predicted polypeptide product possesses a paired domain, a homeodomain, and a serine/threonine-rich carboxy-terminal domain, structural motifs characteristic of certain transcription factors. The concordance between expression and pathology, map location, structure, and predicted function argues that the cDNA corresponds to the AN gene.

Amino Acid Sequence↗

Occupational tuberculous infections among pulmonary physicians in training.

The invasion of the lower respiratory tract by procedures and support measures such as fiberoptic bronchoscopy, endotracheal intubation, and mechanical ventilation generates respiratory aerosols. These aerosols have a potential for the transmission of tuberculosis and other infections. The follow-up of tuberculin skin test status among staff with exposure to this millieu was observed in hope of delineating whether a significant problem does exist. A questionnaire survey of tuberculin skin test status of graduating pulmonary fellows was performed. Graduating Infectious Disease Fellows formed the control group. Training programs situated in the top 25 cities for tuberculosis in 1983 were chosen if the Fellows spent a major proportion of their time in a large receiving/public hospital. The data returned were analyzed if the individual programs had both Pulmonary and Infectious Disease Fellows in training. Fourteen training programs supplied usable data over a 3-yr period. Seven of 62 (11%) of Pulmonary Fellows at risk converted their tuberculin skin test as opposed to one of 42 (2.4%) of Infectious Disease Fellows. This observation raises concern that more fastidious precautions are needed to isolate patients under these conditions of respiratory aerosol generation. The available armamentarium of nonrecirculated fresh air ventilation and ultraviolet light irradiation in addition to simply wearing face masks should be increasingly utilized. Further studies are warranted to substantiate the applicability of these measures to the current situation.

Communicable Diseases↗

Mucosal melanoma of the head and neck.

From 1972 to 1988, 15 patients presented to the Duke University Melanoma Clinic, Durham, NC, with malignant melanoma of the mucus membranes of the upper aerodigestive tract. Eleven patients had a nasopharyngeal origin of their melanoma, while 4 patients had oropharyngeal lesions. The average age of the patients was 58.4 years. Median survival for the patients was 1.8 years, with a 5-year survival of approximately 10%. Survival was found to be independent of sex, tumor site, and extent of disease at presentation. Recurrence occurred in 80% of the patients and the median time to recurrence was 10 months. The median survival following recurrence was 13 months and was independent of the site of recurrence. Mucosal melanoma of the head and neck continues to result in a poor prognosis in spite of aggressive treatment.

Adult↗

Significance of electrocardiographic isolated abnormal terminal P-wave force (left atrial abnormality). An echocardiographic and clinical correlation.

An abnormal terminal negative deflection in precordial lead V1 (PTFV1) is occasionally present as an isolated electrocardiographic finding. To determine the significance of this, 41 patients with PTFV1 greater than or equal to 0.04 mms were recalled for a repeated electrocardiogram as well as an echocardiographic examination. Patients were classified as cardiovascular normal (n = 15) or abnormal (n = 26). Left atrial enlargement was the most common echocardiographic abnormality found, but represented less than a third of the total. P-wave prolongation (greater than 110 ms) was present in 30 of the 41 patients and 21 of the 26 abnormal patients. This persisted into the second study, while the PTFV1 fell significantly in both the normal and abnormal groups. Among the P-wave abnormalities found, combinations were used to identify patients most likely to have cardiovascular disease. The most discriminating was an initial abnormal PTFV1 in combination with P-wave prolongation (sensitivity, 82%; specificity, 40%; positive predictive value, 70%; and negative predictive value, 55%). Maximal specificity (93%) and positive predictive value (88%) were achieved when P-wave prolongation and PTFV1 greater than or equal to 0.06 mms were present in both studies, although the sensitivity for this criterion was only 27%. The isolated P-wave abnormality described may be helpful in suggesting the presence of underlying cardiovascular disease and indicate the need for further evaluation.

Adult↗

Frequency distribution of individuals aged 20-70 years according to severity of periodontal disease.

This study is an analysis of the findings in an epidemiologic investigation covering a random sample of 600 individuals aged 20-70 years resident in the city of Jönköping, Sweden. The frequency distribution of individuals according to severity of periodontal disease was determined. The analysis was based on clinical registration of gingivitis, pocket depths and qualitative and quantitative changes of the alveolar bone in a full mouth intraoral survey. In the age groups 20 and 30 years, 96% and 85% of the individuals, respectively, had healthy periodontal tissues or were grouped as having gingivitis without signs of lowering of the periodontal bone level. In the age groups 40, 50 and 70 years none of the subjects was free from signs of gingivitis/periodontitis but, as for all age groups, strikingly few cases (at most 8%) of severe destructive periodontitis were found. The need for periodontal treatment is discussed as well as the role of specific etiologic agents in the development of destructive periodontal disease.

Adult↗