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Biomedical subjects

S Dunn

Publications and source records attributed to S Dunn.

At least 91 records · Page 5Linked to original sources
PubMed1987

Clinical, functional, and psychosocial characteristics of an incontinent nursing home population.

Although urinary incontinence is recognized as a prevalent, disruptive, and costly problem among nursing home residents, the factors associated with this condition have not been carefully studied. We compared clinical, functional, and psychosocial characteristics of 50 incontinent and 50 continent nursing home residents. In spite of a selection bias due to the informed consent process that resulted in the exclusion of many of the most functionally impaired incontinent residents, the incontinent study participants had significantly greater impairments in functional abilities related to toileting and, on average, took longer to perform a timed series of toileting-related tasks than did the continent comparison group. With the exception of bacteriuria, we did not find incontinence to be associated with most of the major clinical conditions and medications we examined, nor did we find differences in morale and most measures of social activities between the incontinent and continent residents. The data highlight the strong association between functional disability and incontinence in the nursing home setting and suggest that a standard functional assessment of toileting skills could make an important contribution to the care of incontinent residents.

Activities of Daily Living↗
PubMed1986

Mycobacterium chelonei keratitis after radial keratotomy.

Two patients who had undergone radial keratotomy developed delayed postoperative infectious keratitis. Both patients had surgery at the same outpatient facility, and their procedures had been performed by the same surgeon. The corneal lesions appeared similar in both cases, consisting of white irregular infiltrates with radiating projections and fluffy, indistinct margins. Although they were found at all levels, the lesions were most concentrated in the mid-to-deep stroma and were associated with overlying epithelial defects. In both cases, Mycobacterium chelonei was isolated from corneal biopsy specimens. Both patients were treated with topical fortified amikacin; in one there was complete resolution of the corneal infiltrates with medical therapy alone. Although the other patient's lesions initially appeared to resolve with medical therapy, she eventually required corneal transplantation because of recurrence of the infiltrates. Histopathologically, the infiltrates consisted of myriads of acid-fast bacteria with rare inflammatory cell infiltrations.

Adult↗
PubMed1986

Identification of three sites of proteolytic cleavage in the hinge region between the two domains of the beta 2 subunit of tryptophan synthase of Escherichia coli or Salmonella typhimurium.

The beta 2 subunit of tryptophan synthase is composed of two independently folding domains connected by a hinge segment of the polypeptide that is particularly susceptible to limited proteolysis by trypsin [Högberg-Raibaud, A., & Goldberg, M. (1977) Biochemistry 16, 4014-4019]. Since tryptic cleavage in the hinge region inactivates the beta 2 subunit, the spatial relationship between the two domains is important for enzyme activity. However, it was not previously known whether inactivation results from cleavage of the chain or from the loss of internal fragment(s) subsequent to cleavage at two or more sites. We now report comparative studies of limited proteolysis by three proteinases: trypsin and endoproteinases Lys-C and Arg-C. Our key finding that endoproteinase Arg-C inactivates the beta 2 subunit by cleavage at a single site (Arg-275) demonstrates the important role of the hinge peptide for enzymatic activity. We have also identified the sites of cleavage and the time course of proteolysis by trypsin at Arg-275, Lys-283, and Lys-272 and by endoproteinase Lys-C at Lys-283 and Lys-272. Sodium dodecyl sulfate gel electrophoresis, Edman degradation, and carboxypeptidases B and Y have been used to identify the several fragments and peptides produced. Our finding that the beta 2 subunit and F1 fragments have a heterogeneous amino terminus (Met-1 or Thr-2) indicates that the amino-terminal methionine is incompletely removed during posttranslational modification. Our results show that Edman degradation can be effectively used with a protein of known sequence to analyze proteolytic digests that have at least four different amino-terminal sequences.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1985

Outpatient stabilization programme--an innovative approach in the management of diabetes.

An outpatient stabilization programme for diabetic patients was established to overcome the disadvantages of inpatient treatment. The day to day management of patients was carried out by experienced nurse/educators under the supervision of physicians. The telephone was used extensively for communication between the patients and staff of the Diabetes Centre. In a 12 month period, 73 patients were commenced on insulin and 83 patients (62 on insulin) had their diabetic control re-stabilized. In both groups of patients there was a significant fall in glycosylated haemoglobin levels indicating improved metabolic control. Results were similar to those for patients admitted to hospital for stabilization. There are important social and economic benefits from the avoidance of repeated hospitalization.

Academic Medical Centers↗
PubMed1984

Endothelial cell loss following radial keratotomy in a primate model.

The effect of radial keratotomy on the corneal endothelium of subhuman primates was studied by serial specular microscopy and histopathology. Fixed-frame analysis of specular micrographs of 13 operated eyes at one month after surgery revealed an endothelial cell loss of 13% (+/- 4%). Follow-up of all 13 eyes for six months disclosed no statistically significant progressive endothelial cell loss. Similarly, no significant loss could be demonstrated in five eyes followed up for 18 months and two eyes followed up four years after surgery. Variable frame analyses of specular micrographs of all 13 unoperated eyes followed up for six months also did not suggest progressive endothelial cell loss following radial keratotomy. Histopathology and ultrastructural studies of corneas undergoing radial keratotomy disclosed no abnormalities suggesting ongoing endothelial cell damage. These findings suggest that radial keratotomy produces an acute postoperative endothelial cell loss that is nonprogressive. Much longer term follow-up with larger numbers of subjects is necessary before the ultimate delayed effects of radial keratotomy on the endothelium can be determined.

Animals↗
PubMed1984

Hematoporphyrin derivative photoradiation induced damage to normal and tumor tissue of the pigmented rabbit eye.

Cytotoxicity induced by hematoporphyrin derivative (HpD) photoradiation in both normal and experimental tumor tissue of pigmented rabbit eyes has been examined. In addition, documentation of HpD induced fluorescence in ocular structures has also been obtained. Acute normal ocular tissue toxicity studies demonstrated that HpD (1-10 mg HpD/kg) followed 48 hours later by a transpupil irradiation of red light (635 nm, 36-90 J/cm2) resulted in demarcated areas of retinal damage. Long term (chronic) toxicity studies have shown that the initial damage to the retina was permanent but that no damage to the cornea, lens or vitreous could be observed during a 16 month follow-up. Visual and histological documentation have been obtained, following HpD photoradiation therapy (PRT), in rabbit eyes having heterotransplanted single nodule amelanotic melanomas. A toxic effect characterized by tumor blanching, edema and hemorrhage was observed within 24 hours of treatment. Histological examination obtained 24 hours following HpD PRT illustrated massive tumor tissue necrosis and vascular disruption. HpD PRT at clinically relevant doses was also shown to be effective in selectively curing the highly malignant amelanotic iris melanoma. It is concluded that HpD PRT may prove to be an effective modality for treating certain ocular tumors.

Animals↗
PubMed1984

Natural history of experimental histoplasmic choroiditis in the primate. I. Clinical features.

The clinical features of the long-term (3-year) natural history of experimental histoplasmic choroiditis in primates are documented in this report. The acute choroiditis resolved into four types of lesions: chorioretinal adhesions (atrophic scars) (2%); retinal pigment epithelial window defects (21%); subclinical lesions (19%); and "disappearing" lesions (58%). It was noted that the most obvious, acute lesions tend to disappear by clinical examination with long-term follow up. No subretinal neovascularization or spontaneous "reactivation" was observed.

Animals↗
PubMed1984

Natural history of experimental histoplasmic choroiditis in the primate. II. Histopathologic features.

The histopathologic features of experimental multifocal histoplasmic choroiditis in the primate are presented. Eyes were studied at various time periods from 30 days to 3 years after intracarotid injection with live Histoplasma capsulatum organisms. The acute lesions produced resolved into four distinct resolution patterns (chorioretinal scars, retinal pigment epithelial defects, subclinical lesions, and "disappearing" lesions) whose histopathologic features were studied. Organisms could not be demonstrated by culture or special stains in lesions present more than 6 weeks. A feature common to all eyes studied, including those whose lesions were clinically inactive or had clinically "disappeared," was the persistence of small foci of lymphocytes in the choroid. Damage to Bruch's membrane was observed in some specimens.

Animals↗
PubMed1983

Nuclease digestion patterns as a criterion for nucleosome orientation in the higher order structure of chromatin.

Nuclease digestion patterns have been used to discriminate between possible orientations of nucleosomes in the higher order structure of chromatin. Computer simulations were done assuming 3 basically different orientations of nucleosomes which include all proposed models for the '30 nm fibre'. It is found that only alternating exposure of consecutive nucleosomes can explain the DNase I and DNase II digestion patterns.

Animals↗
PubMed1983

Acute peptic ulcer in childhood. Emergency surgical therapy in 39 cases.

Acute peptic ulcers occurred in 39 infants and children, 22 girls and 17 boys. Eleven patients were less than one year of age. Peptic ulcers were secondary to systemic disease or ulcerogenic medications in 34 cases. Hemorrhage occurred in 27 patients, perforation in 12. Endoscopy was the most useful diagnostic procedure for hemorrhage. Free air was seen on abdominal roentgenogram in all perforated patients. Ligation of the ulcer bed, vagotomy, and pyloroplasty were performed in 25 patients with bleeding. One patient required total gastrectomy. Simple plication was performed in nine patients with perforation. Plication was combined with pyloroplasty and tube duodenostomy in one patient each, and vagotomy and antrectomy were required in one patient. Operative mortality was 5.2%. There were two late deaths (Reye's syndrome and burn sepsis). No ulcer has recurred.

Acute Disease↗