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T Jordan

Publications and source records attributed to T Jordan.

At least 37 records · Page 2Linked to original sources
PubMed1995

Secondary and tertiary structure of the A-state of cytochrome c from resonance Raman spectroscopy.

Ferricytochrome c can be converted to the partially folded A-state at pH 2.2 in the presence of 1.5 M NaCl. The structure of the A-state has been studied in comparison with the native and unfolded states, using resonance Raman spectroscopy with visible and ultraviolet excitation wavelengths. Spectra obtained with 200 nm excitation show a decrease in amide II intensity consistent with loss of structure for the 50s and 70s helices. The 230-nm spectra contain information on vibrational modes of the single Trp 59 side chain and the four tyrosine side chains (Tyr 48, 67, 74, and 97). The Trp 59 modes indicate that the side chain remains in a hydrophobic environment but loses its tertiary hydrogen bond and is rotationally disordered. The tyrosine modes Y8b and Y9a show disruption of tertiary hydrogen bonding for the Tyr 48, 67, and 74 side chains. The high-wavenumber region of the 406.7-nm resonance Raman spectrum reveals a mixed spin heme iron atom, which arises from axial coordination to His 18 and a water molecule. The low-frequency spectral region reports on heme distortions and indicates a reduced degree of interaction between the heme and the polypeptide chain. A structural model for the A-state is proposed in which a folded protein subdomain, consisting of the heme and the N-terminal, C-terminal, and 60s helices, is stabilized through nonbonding interactions between helices and with the heme.

Animals↗
PubMed1994

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↗
PubMed1992

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↗
PubMed1991

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↗
PubMed1990

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↗
PubMed1989

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↗
PubMed1988

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↗