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Biomedical subjects

R S Singer

Publications and source records attributed to R S Singer.

30 records · Page 2Linked to original sources
PubMed1995

Dilemmas associated with rehousing homeless people who have companion animals.

66 individuals were given a questionnaire during the initial visit to a veterinary clinic for homeless pet owners. Among the 35 men and 31 women, 32 had been homeless for 6 mo. or less and were termed the acutely homeless subgroup, and 34 had been homeless multiple times or for more than 6 mo. and were termed the chronically homeless subgroup. In responding to the Lexington Attachment to Pets Scale, both men and women participants had significantly higher mean scores on attachment to their pets than did the scale's standardization population. Participants did not differ from the normative sample of adults on the Beck Hopelessness Scale. Both men and women participants stated a preference for being rehoused. 93% of men and 96% of women said that housing would not be acceptable if pets were not allowed. 61% of the men and 33% of the women stated they would be willing to live anywhere pets were allowed except in a shelter. Reluctance to live in a shelter was significantly greater among chronically homeless men than other subgroups, and they also had low desire to be rehoused. A majority of the participants had been refused housing because they had pets. Attempts to rehouse homeless individuals who have pets are likely to be unsuccessful unless accommodation for pets is included.

Adult↗
PubMed1993

Restoration of collagen formation in photodamaged human skin by tretinoin (retinoic acid)

BACKGROUND: Topical tretinoin (retinoic acid) modifies fine wrinkles and certain other features of human skin damaged by exposure to the sun (photodamage), but histologic changes do not account for this improvement. In mice with photodamage induced by ultraviolet light, effacement of fine wrinkles by tretinoin is correlated with dermal collagen synthesis but not with histologic changes. We investigated whether collagen synthesis was reduced in photodamaged human skin and, if so, whether it could be restored by treatment with topical tretinoin. METHODS: Biopsies of photodamaged skin from the extensor aspect of the forearm and skin from the buttocks, which had been protected from the sun, were performed on 26 healthy subjects. In addition, 29 patients with photodamaged skin were treated for 10 to 12 months with a daily application of 0.1 percent tretinoin cream (15 patients) or vehicle cream (14 patients). Skin-biopsy specimens obtained at base line and after treatment were assessed immunohistologically for evidence of dermal collagen I formation (collagen synthesis). RESULTS: Collagen I formation was 56 percent less in the papillary dermis of photodamaged skin than in skin protected from the sun (P < 0.001) and was correlated with the clinical severity of photodamage (r = -0.58, P = 0.002). Treatment of photodamaged skin with tretinoin produced an 80 percent increase in collagen I formation, as compared with a 14 percent decrease in collagen formation with the use of vehicle alone (P = 0.006). CONCLUSIONS: The formation of collagen I is significantly decreased in photodamaged human skin, and this process is partly restored by treatment with tretinoin.

Adult↗
PubMed1985

A comparison between superior and inferior border wiring techniques in sagittal split ramus osteotomy.

The proper alignment of the proximal and distal segments after the sagittal split ramus osteotomy (SSRO) has been a major concern since this procedure was first performed. Because of this problem, a comparison was made between a superior border wiring technique and an inferior border wiring technique. This involved the preoperative and postoperative lateral cephalograms of 35 patients from the Department of Oral Surgery at the Medical College of Georgia who received a SSRO with advancement. Nineteen patients received an inferior border wire and 16 patients received a superior border wire. The areas studied were anterosuperior rotation of the proximal segment, increase in gonial angle, and condylar sag. A cephalometric evaluation and a computer analysis were performed. It was found that the inferior border wiring technique produces a statistically significant lesser amount of anterosuperior rotation of the proximal segment and less increase in gonial angle than the superior border wiring technique. Because of these findings, it was felt that the inferior border wiring techniques produce less displacement of the proximal segment in the SSRO advancement.

Cephalometry↗
PubMed1985

Picnic headaches.

Explore the source record for details and available documents.

Headache↗
PubMed1984

A simple means of maintaining light handle sterility.

The maintenance of sterility of the light handle in an economical and effective manner can be difficult. Heavy-duty aluminum foil is suggested as a simple and inexpensive material to be used to maintain such sterility in the clinical practice of oral and maxillofacial surgery.

Lighting↗
PubMedDate not supplied

Virulence factors of Escherichia cofi from cellulitis or colisepticemia lesions in chickens.

This study was designed to compare virulence factors of cellulitis-derived Escherichia coli to colisepticemic E. coli in order to clarify whether E. coli associated with cellulitis comprise a unique subset of pathogenic E. coli. Isolates were tested for serotype, capsule, aerobactin production, colicin production, the presence of the iss gene, and serum resistance. Untypable isolates made up the greatest percentage of each group. Serotypes O2 and O78 were the most commonly identified among both groups of isolates. No statistical differences in the distribution of aerobactin or colicin production, capsule, or iss gene were observed between groups. Cluster analysis showed that 90% of the E. coli isolates had greater than 42% livability in serum-resistance tests. No separation of colisepticemic vs. cellulitis E. coli isolates was observed on the basis of SR. Colicin production by E. coli was highly correlated with serum resistance (P = 0.0029). These data suggest that cellulitis E. coli have virulence traits similar to those of colisepticemic E. coli.

Animals↗
PubMedDate not supplied

Prevalence of pathogenic Escherichia coli in the broiler house environment.

Matched sampling of Escherichia coli from broiler house litter and bird lesions of either cellulitis or colibacillosis was conducted to investigate the relationship of pathogenic E. coli to those found in the environment. Isolates were collected from six broiler flocks representing six geographically disparate ranches. Isolates were compared by flock for similarity in serotype and genotyped by pulsed-field gel electrophoresis. Serotyping revealed a considerable dissociation between the two groups of isolates. The prevalence of pathogenic E. coli that matched the environmental isolates from the same house was 0 to 3%. Statistical analysis of the serotype data showed a strong dependence of serotype on isolate source, indicating a high probability that a particular serotype would be found among lesions or litter but not in both groups. Genotyping of isolates on two farms supported the results of serotyping and provided differentiation of isolates that could not by typed by serology. These results suggested that the prevalence of pathogenic E. coli in the broiler house was independent of the prevalence of other commensal or environmental E. coli. Understanding the composition of E. coli populations in commercial poultry production may have bearing on the epidemiology and control of E. coli related diseases.

Animal Husbandry↗
PubMedDate not supplied

Assessing cellulitis pathogenicity of Escherichia coli isolates in broiler chickens assessed by an in vivo inoculation model.

The purpose of this study was to identify Escherichia coli isolates that could be characterized as cellulitis pathogens. Twelve E. coli isolates from diagnostic cases of cellulitis or mixed infections with various serotypes were compared for ability to produce cellulitis and internal lesions indicative of systemic infection. Ranking of isolates was based on the premise that E. coli isolates that were "cellulitis-type" would cause cellulitis lesions without causing systemic infection. A quantitative scoring system was also used so both the time required for a lesion to develop and lesion severity could be evaluated as determinants of virulence. Escherichia coli isolates were inoculated by subcutaneous injection of a standardized dose in 24 broiler chickens per isolate. Necropsy was performed on four birds per group at 6, 12, 24, 36, 48, and 60 hr postinoculation (PI). Cellulitis lesions were scored on a 0 to 5 scale based on size, migration from the inoculation site, and gross characteristics. Lesions of the pericardium, liver, joint, or body cavity were evaluated. Gross lesion scores of 1 or 2 were evident by 6 hr PI with all isolates. Mortality occurred in 4 of 12 experimental groups. Internal lesions were observed in 3 to 12 birds per group. Escherichia coli was reisolated from all lesions. The four isolates with the highest lesion score and highest lesion points as determined by the quantitative scoring system did not vary. However, the rankings of two other isolates were affected. Four isolates that were below average for mean internal lesion score and above average for mean cellulitis points were characterized as cellulitis-type. Three isolates that were above average for internal lesion score and below average for mean cellulitis points were characterized as systemic-type. The E. coli serotype was not a determining factor for cellulitis-type pathogenicity. Isolates discriminated as cellulitis-type or septicemic-type E. coli in this study are being used to further investigate virulence factors involved in the pathogenesis of cellulitis in broiler chickens.

Animals↗
PubMedDate not supplied

Spatial heterogeneity of Escherichia coli DNA fingerprints isolated from cellulitis lesions in chickens.

Avian cellulitis in broiler chickens is characterized by subcutaneous lesions that result in economic losses because of the partial or complete condemnation of the carcasses at processing. Escherichia coli is the primary causative agent of this condition. Previous research with a biotyping system found that the E. coli of cellulitis origin were unique to each ranch, suggesting that these E. coli were endemic within the ranch environment. The objective of our study was to analyze the genetic variability of E. coli isolates associated with cellulitis. We analyzed the genetic relatedness of the isolates in relation to the houses, ranches, and complexes in which the broilers were grown. This analysis enabled us to assess the spatial heterogeneity, or genetic diversity on a spatial scale, of the isolates. Forty-nine broilers with cellulitis lesions were necropsied. These broilers came from six houses on four ranches on three complexes that had been placed with chicks from the same hatchery within a 2-wk period. Isolates of E. coli from the lesions were DNA fingerprinted by pulsed-field gel electrophoresis. Relatedness among isolates was determined with the Dice coefficient and an unweighted pair group method with average linkages cluster analysis. The complexes possessed isolates with a variety of DNA fingerprints, yet each complex appeared to have isolates with a unique set of DNA fingerprints. Isolates from the same complex tended to form clusters with similarity coefficients greater than 90%. Isolates from different complexes were genetically distinct. This heterogeneity at the level of the complex suggests that isolates were not disseminated from a source common to the complexes. The spatial heterogeneity of the E. coli isolates in this study implies an endemic population of cellulitis-associated E. coli exists in the broiler house environment.

Animals↗