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Biomedical subjects

A Shalom

Publications and source records attributed to A Shalom.

At least 19 recordsLinked to original sources
PubMed2001

Acellular allograft dermal matrix: immediate or delayed epidermal coverage?

In a prospective, randomized study seventeen patients received skin grafts to a freshly excised burn wound. One group was grafted with a deantigenized dermal matrix and immediately overgrafted with thin autograft. The second group was grafted with dermal matrix, which was then covered with bank allograft for protection, and autografted 1 week later. Each group also received a standard split thickness control graft. Assessment was carried out for up to 1 year. There were no statistically significant differences of graft take between any of the groups, or in the Vancouver scar score at follow-up. Thin donor sites used for dermal matrix coverage healed faster than standard control graft sites, P<0.001. Immediate grafting of acellular dermal matrix with thin autograft works well and leads to an acceptable late result, with faster donor site healing than standard split thickness grafts.

Adult↗
PubMed2001

Intraoperative positioning for circumferential extremity burns.

A technique for intra-operative patient positioning is described which allows circumferential access to burned extremities for prepping and surgery. This technique avoids the need for turning the patient during the operative procedure. In our 13 yr experience, there have been no complications attributed to this technique.

Burns↗
PubMed2001

Effect of high dose and low dose aspirin on survival of random pattern flaps in rats.

This paper studies which of the physiological effects of aspirin is responsible for increasing the survival of random flaps in rats, found in an earlier experiment. We wished to confirm that the antiaggregating--antithrombotic effect was responsible for the increased survival of flaps without microvascular anastomosis. Three groups of rats with standardised random pattern flaps were used. The first two were given aspirin 200 mg/kg (high dose, n = 27) or 40 mg/kg (low dose, n = 21) and the third (n = 28) acted as controls. The beneficial effects of aspirin were restricted to the high dose group. Since the low dose group also showed antiaggregation of platelets, but without the anti-inflammatory or vasodilatory effects, the results indicate that the antiaggregating effect alone was not responsible for the increased survival of the flaps.

Analysis of Variance↗
PubMed2000

Inflammatory fibroid polyp and Helicobacter pylori. Aetiology or coincidence?

OBJECTIVE: To evaluate our incidence of inflammatory fibroid polyps, compare our experience with that of others, and to analyze the possible pathophysiological and aetiological factors. DESIGN: Retrospective review. SETTING: Teaching hospital. MATERIAL: All histopathological slides of the gastrointestinal tract. MAIN OUTCOME MEASURES: Incidence and treatment in our Medical Center and elsewhere. RESULTS: We could find only one case of inflammatory fibroid polyp, an estimated incidence of 1/4000. Between 1987-1996 only 331 were reported elsewhere, most of which (293, 88.5%), were located in the stomach. CONCLUSION: Primary mucosal damage can expose the stroma to several irritants (chemical, mechanical and biological), that may subsequently cause inflammatory fibroid polyps in certain people.

Amoxicillin↗
PubMed1998

Prevention of needle-stick injury by the scooping-resheathing method.

BACKGROUND: The objective of this study was to determine the effects of teaching the scooping-resheathing method on the incidence of needle-stick injuries in medical students. METHODS: Before starting their first clerkship, 81 medical students were given a 15-min lecture on the high incidence and dangers of needle-stick injuries and a demonstration of the scooping-resheathing method. The number of needle-stick injuries that occurred during the 3-month clerkship was compared with the number reported by 86 medical students who had completed their first clerkship 1 year previously and had not been given such instruction. RESULTS: Compared with controls, the study group had a 3.8-fold lower risk of needle-stick injury (95% confidence interval, 2.0-7.4, P < 0.0001) and a 8.3-fold lower risk of multiple needle-stick injuries (95% confidence interval, 2.0-35.0, P < 0.001). Those in the study group, who consistently used the scooping method had a much lower risk of injury than those who did not (1 of 36 [2.8%] vs. 8 of 45 [17.4%], P = 0.039). CONCLUSIONS: We conclude that a lecture recommending the scooping-resheathing method is effective in reducing the risk of needle-stick injuries in medical students during their first rotation. Because this is the first time that an intervention not requiring change in equipment has been successful, further studies are warranted to substantiate our findings and for extrapolation to other medical personnel in other cultural settings.

Accidents, Occupational↗
PubMed1998

Quantitative trait locus mapping in dairy cattle by means of selective milk DNA pooling using dinucleotide microsatellite markers: analysis of milk protein percentage.

"Selective DNA pooling" accomplishes quantitative trait locus (QTL) mapping through densitometric estimates of marker allele frequencies in pooled DNA samples of phenotypically extreme individuals. With poly(TG) microsatellites, such estimates are confounded by "shadow" ("stutter") bands. A correction procedure was developed on the basis of an observed linear regression between shadow band intensity and allele TG repeat number. Using this procedure, a selective DNA pooling study with respect to milk protein percentage was implemented in Israel-Holstein dairy cattle. Pools were prepared from milk samples of high and low daughters of each of seven sires and genotyped with respect to 11 markers. Highly significant associations with milk protein percentage were found for 5 of the markers; 4 of these markers confirmed previous reports. Selective DNA pooling accessed 80.6 and 48.3%, respectively, of the information that would have been available through individual selective genotyping or total population genotyping. In effect, the statistical power of 45,600 individual genotypings was obtained from 328 pool genotypings. This methodology can make genome-wide mapping of QTL accessible to moderately sized breeding organizations.

Animals↗
PubMed1997

Primer tRNA3Lys on the viral genome exists in unextended and two-base extended forms within mature human immunodeficiency virus type 1.

In human immunodeficiency virus type 1, tRNALys3 is placed upon the primer binding site, where it serves as the primer for reverse transcription. We show herein that genomic placement occurs independently of precursor protein processing and that the placed tRNALys3 exists in two major forms: unextended or in a form extended by the first two DNA bases incorporated, C and T. The two-base extended form of the tRNALys3 is absent in a protease-negative mutant, indicating a requirement for mature viral proteins to initiate reverse transcription within the virus.

Animals↗
PubMed1996

Multiple forms of tRNA(Lys3) in HIV-1.

tRNALys3 is the primer for HIV-1 reverse transcriptase (RI) and is selectively incorporated into HIV-1 during viral assembly. While whole cell extracts of uninfected or infected cells contain only one detectable form of tRNALys3, multiple forms of tRNALys3 are detected in the virus released into the cell culture media. These tRNALys3 isoacceptors are found in HIV-1 produced from newly infected cord blood lymphocytes and from cells chronically infected with HIV-1, such as the lymphocytic cell line H9 and the monocytic cell lines U937 and PLB. They can be detected through the use of either RPC-5 column chromatography of tRNA aminoacylated with radioactive lysine or northern blot analysis using a tRNALys3-specific DNA hybridization probe. Both RPC-5 chromatography and northern blot analysis show the cytoplasmic form of tRNALys3 to be the major abundance form of tRNALys3 in the virus. Starting with the viral RNA isolated from HIV (PLB), the tRNALys3 species resolved by RPC-5 into peaks 2, 3, and 4 were deacylated and 3' end-labeled by heat-annealing the RNA in each peak to synthetic HIV genomic RNA, and extending the hybridized species one base using HIV-1 RT and radioactive dCTP. An electrophoretic comparison of the partial T1 digest pattern of purified human placental tRNALys3 with those of the RPC-5 resolved species showed that the labeled RNA species in each peak was tRNALys3. These radioactive tRNALys3 species retained their relative mobilities when rechromatographed on RPC-5. When total HIV (PLB) RNA was used as the source of primer/template, and similarly extended with RT in the presence of radioactive dCTP, the major priming tRNA resolved by RPC-5 had a chromatographic mobility identical to peak 3. This tRNA primer has a T1 digest pattern identifying it as tRNALys3. These results indicate that the major tRNALys3 species present in the virus is also the major tRNALys3 isoacceptor used as the primer for reverse transcription.

Base Sequence↗
PubMed1996

Single-parent segregant pools for allocation of markers to a specified chromosomal region in outcrossing species.

Bulked co-segregant analysis is a method of rapidly allocating unmapped genetic markers to a specific chromosomal region. Although originally developed for utilization in populations derived from crosses between fully inbred lines, it has been proposed that co-segregant pools could also serve the same purpose in outbreeding populations, if individuals from only a single large family are pooled. Large, fully mapped, single-sire backcross and half-sib families are presently available as part of the international chicken and bovine reference family panels respectively. In this study, power and tests of significance for single-parent co-segregant analysis are derived for full-sib, single-parent back-cross and single-parent half-sib families, as a function of proportion of recombination between index marker and linked marker, pro-portion of single-parent alleles among the mates, number of individuals in each segregant pool and technical error variance. Power was found to be greater than 0.80 for many reasonable parameter combinations. The method is illustrated using microsatellite markers and a large single-sire bovine family, part of the international bovine reference family panel.

Alleles↗
PubMed1996

Effects of modifying the tRNA(3Lys) anticodon on the initiation of human immunodeficiency virus type 1 reverse transcription.

tRNA(3Lys) is a primer for reverse transcription in human immunodeficiency virus type 1 (HIV-1), and the anticodon of tRNA(3Lys) has been implicated in playing a role in both its placement onto the HIV-1 genome and its interaction with HIV-1 reverse transcriptase (RT). In this work, the anticodon in a tRNA(3Lys) gene was changed from UUU to CUA (tRNA(3Lys)Su+) or, in addition, G-73 was altered to A (tRNA(3Lys)Su+G73A). COS-7 cells were transfected with either wild-type or mutant tRNA(3Lys) genes, and both the wild-type and mutant tRNA(3Lys) produced were purified by using immobilized tRNA-specific hybridization probes. Each mutant tRNA(3Lys) was tested for its ability to prime reverse transcription in vitro, either alone or in competition with wild-type tRNA(3Lys). Short RT extensions of wild-type and mutant tRNALys could be distinguished from each other by their different mobilities in one-dimensional single-stranded conformation polymorphism polyacrylamide gel electrophoresis. These reverse transcription products show that heat-annealed tRNA(3Lys)Su+ has the same ability as heat-annealed wild-type tRNA(3Lys) to prime RT and competes equally well with wild-type tRNA(3Lys) for priming RT. tRNA(3Lys)Su+G73A has 60% of the wild-type ability to prime RT but competes poorly with wild-type tRNA(3Lys) for priming RT. However, the priming abilities of wild-type and mutant tRNA(3) are quite different when in vivo-placed tRNA is examined. HIV-1 produced in COS cells transfected with a plasmid containing both the HIV-1 proviral DNA and DNA coding for tRNA(3Lys)Su+ contains both endogenous, cellular wild-type tRNA(3Lys) and mutant tRNA(3Lys). When total viral RNA is used as the source of primer tRNA placed onto the genomic RNA in vivo, only wild-type tRNA(3Lys) is used as a primer. If the total viral RNA is first heated and exposed to hybridizing conditions, then both the wild-type and mutant tRNA(3Lys) act as primers for RT. These results indicate that the tRNA(3Lys)Su+ packaged into the virions is unable to act as a primer for RT, and a model is proposed to explain the disparate results between heat-annealed and in vivo-placed primer tRNA.

Anticodon↗
PubMed1995

Needlesticks in medical students in university hospitals.

The incidence of needlesticks and the effect of experience and other personal characteristics on the risk of needlesticks in medical students are unknown. Eighty-nine medical students were given a self-administered questionnaire. The questionnaire was completed by 86 students, and there were 91 sticks in 43 students. The incidence of needlesticks was 5.8/1000 procedures on the first rotation and 0.1/1000 during the second 4-month period (relative risk, 6.5, with 95% confidence interval (CI) of 3.4-125; P < 0.001). Personal characteristics were not associated with needlesticks except for tension felt while drawing blood and accident proneness. Those who were stuck during the first rotation were more likely to be stuck subsequently (odds ratio, 9.0, with 95% CI of 1-422; P < 0.05). We conclude that experience decreases the risk for needlesticks and therefore effective instructional intervention may have the biggest impact during the first medical student ward experience. Emphasis may have to be placed on those students who are accident prone or have been stuck in the past. Further studies are warranted to substantiate our findings and to test the effectiveness of various interventional approaches.

Adult↗
PubMed1994

A genetic linkage map of the bovine genome.

A cattle genetic linkage map was constructed which marks about 90% of the expected length of the cattle genome. Over 200 DNA polymorphisms were genotyped in cattle families which comprise 295 individuals in full sibling pedigrees. One hundred and seventy-one loci were found linked to one other locus. Twenty nine of the 30 chromosome pairs are represented by at least one of the 36 linkage groups. Less than a 50 cM difference was found in the male and female genetic maps. The conserved loci on this map show as many differences in gene order compared to humans as is found between humans and mice. The conservation is consistent with the patterns of karyotypic evolution found in the rodents, primates and artiodactyls. This map will be important for localizing quantitative trait loci and provides a basis for further mapping.

Animals↗
PubMed1993

Milk as a source of deoxyribonucleic acid and as a substrate for the polymerase chain reaction.

Somatic cells in milk were used as a source of DNA and as a substrate for the polymerase chain reaction. Successful DNA extraction required a minimum total of 17 x 10(6) cells in the milk sample. The DNA yield per cell was highly variable but comparable, on average, with the yield from peripheral blood leukocytes. In all cases, direct polymerase chain reaction on milk samples, using a variety of primer pairs, yielded amplified products of correct size that were identical to those obtained by polymerase chain reaction of purified DNA extracted from milk or blood. Milk and DNA extracted from milk served as substrates for direct sequencing of part of the bovine growth hormone gene. Milk samples with added preservative were stored over 200 d without effect on the polymerase chain reaction. Thus, milk can often substitute for blood as a source of DNA for Southern blot analysis and is a preferred substrate for the polymerase chain reaction. The technical convenience of milk as a source of DNA can be expected to increase the field of application of marker-based methods for genetic analysis and genetic improvement of economic traits in dairy cattle.

Animals↗