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Biomedical subjects

S Crow

Publications and source records attributed to S Crow.

At least 19 recordsLinked to original sources
PubMed1992

Unstable DNA sequence in myotonic dystrophy.

A variable DNA sequence has been detected in patients with myotonic dystrophy. We set out to determine whether identification of this specific molecular defect would improve clinical management of patients and families with myotonic dystrophy. 127 affected patients who were studied had an expanded DNA fragment not seen in 73 normal controls. The increase in length of the fragment correlated broadly with disease severity, and we noted expansion of the sequence in successive generations of the same family. Progressive expansion of the affected gene provides a molecular explanation for an apparently earlier onset in successive generations (anticipation) in myotonic dystrophy and supports the role of an unstable repeat sequence as the basis of the defect. The specificity of this finding will assist in accurate diagnosis of myotonic dystrophy and genetic counselling of affected families.

Adolescent↗
PubMed1992

Expansion of an unstable DNA region and phenotypic variation in myotonic dystrophy.

Myotonic dystrophy is the commonest adult form of muscular dystrophy, with an estimated incidence of 1 per 7,500, although this is likely to be an underestimate because of the difficulty of detecting minimally affected individuals. It is a multisystem autosomal dominant disorder of unknown biochemical basis. No case of new mutation has been proven. We have isolated a human genomic clone that detects novel restriction fragments specific to individuals with myotonic dystrophy. A two-allele EcoRI polymorphism is seen in normal individuals, but in most affected individuals one of the normal alleles is replaced by a larger fragment, which varies in length both between unrelated affected individuals and within families. The unstable nature of this region may explain the characteristic variation in severity and age at onset of the disease. A second polymorphism at this locus is in almost complete linkage disequilibrium with myotonic dystrophy, strongly supporting our earlier results which indicated that most cases are descended from one original mutation.

Blotting, Southern↗
PubMed1992

Radiation-reduced hybrids for the myotonic dystrophy locus.

The myotonic dystrophy (DM) gene maps to the long arm of human chromosome 19 and is flanked by markers ERCC1 and D19S51. Also mapping to this region is the polio virus receptor gene (PVS). To produce more markers for this interval, we have constructed radiation-reduced hybrids by selecting for the retention of ERCC1 and for the loss of PVS. One of the cell lines produced has been characterized extensively and contains about 2 Mb of human DNA derived exclusively from chromosome 19, and includes ERCC1 and D19S51. Phage libraries constructed from DNA of this cell line have been screened and several new markers identified, including two for which cDNAs have been isolated. These represent candidate genes for DM. The new markers have also been used to extend the long-range restriction map of this region.

Base Sequence↗
PubMed1992

Minimal expression of myotonic dystrophy: a clinical and molecular analysis.

A clinical and molecular study is reported of 83 patients considered to be minimally affected with myotonic dystrophy (DM). These had been identified in three ways: 60 subjects were identified on clinical grounds and were divided into those with and those without neuromuscular involvement (groups I and II); nine subjects were at high risk of carrying the DM gene but had a normal phenotype (group III); and 14 were parents of definitely affected patients where neither parent showed clinical abnormalities (group IV). PCR analysis of the CTG repeat in the DM gene showed a range of 70 to 230 repeats for the younger at risk patients in group III, while the asymptomatic gene carriers in group IV had 53 to 60 repeats. The sensitivity of diagnosis by EMG was found to be 39%. For ophthalmic signs this was 97.5%. This suggests that assignment on the basis of minimal clinical features carries a significant error. Molecular analysis, in conjunction with established clinical investigations, should prove valuable in the identification and exclusion of minimal myotonic dystrophy.

Adult↗
PubMed1991

Health care personnel's perception of infection control.

Although the administration believes the 20-year-old infection program at the authors' institution has been effective in reducing nosocomial infection risk, the perceptions of nurses and physicians were unknown. Two hundred and twenty-seven nurses and 50 physicians were surveyed to determine their concept of infection control. Of all surveyed, 97% considered handwashing the most critical aspect of infection control and felt that additional teaching would increase this practice. Although physicians (40%) and nurses (30%) surmised the major infection control problem was lack of handwashing, 95% of physicians and 90% of nurses believed they personally washed their hands correctly and appropriately. One-half of all surveyed were not able to define 'asepsis' correctly. Sixty percent of nurses and 70% of physicians were not familiar with a monthly nosocomial report. On-site inspections and more educational programs were the primary recommendations of nurses and physicians. Of all participants, 99% could name the infection control nurse, whereas only 11% could name the infection control committee chairman. Although most infection control nurses feel they create a negative impression when they make rounds, the attitudes of nurses (81%) and physicians (68%) were positive. It is concluded that the perception of infection control differs among nurses and physicians. An effective infection control program must address the specific needs of all groups.

Attitude of Health Personnel↗
PubMed1991

Detection of linkage disequilibrium between the myotonic dystrophy locus and a new polymorphic DNA marker.

We have examined the linkage of two new polymorphic DNA markers (D19S62 and D19S63) and a previously unreported polymorphism with an existing DNA marker (ERCC1) to the myotonic dystrophy (DM) locus. In addition, we have used pulsed-field gel electrophoresis to obtain a fine-structure map of this region. The detection of linkage disequilibrium between DM and one of these markers (D19S63) is the first demonstration of this phenomenon in a heterogeneous DM population. The results suggest that at least 58% of DM patients in the British population, as well as those in a French-Canadian subpopulation, are descended from the same ancestral DM mutation. We discuss the implications of this finding in terms of strategies for cloning the DM gene, for a possible role in modification of risk for prenatal and presymptomatic testing, and we speculate on the origin and number of existing mutations which may result in a DM phenotype.

Chromosomes, Human, Pair 19↗
PubMed1990

It's second nature to me now. OR rituals.

Insufficient data exist relating to surgical asepsis; relying solely on data collection to determine practices limits patient care. Until clinical data are available that support or disclaim established traditions, it may be wise to hold customs that we believe have kept the patient safe. Rituals define and maintain sterility and provide freedom; certain traditions become part of the OR team's practice so that attention can be focused on the surgical procedure. As professional nurses, it is our responsibility to question dogma and to change our rituals when studies indicate the need for change.

Asepsis↗
PubMed1989

Microbial contamination of arterial infusions used for hemodynamic monitoring: a randomized trial of contamination with sampling through conventional stopcocks versus a novel closed system.

Arterial catheters are now commonly used to monitor blood pressure and obtain blood samples for arterial blood gas and other laboratory determinations. Stopcocks inserted into the pressure monitoring circuit have been the primary means of obtaining blood from arterial catheters. However, these stopcock systems have been associated with nosocomial contamination and bacteremias. Because of the problems of bacterial contamination and blood wasting with the stopcock sampling systems, we compared the frequency and extent of contamination of external sampling ports and the monitoring tubing fluid in stopcocks with that of a novel closed needle-sampling system (Lab-Site, Migada Ltd, Rehovot, Israel), incorporated into pressure monitoring tubing (Abbott Laboratories Inc., North Chicago, Illinois). We found that use of the novel sampling system resulted in significantly fewer episodes of internal bacterial contamination of the arterial monitoring line (7%) than did the use of a stopcock system (61%). External contamination of the sampling port was also lower in the novel system (8%) than in the stopcock system (37%). This suggests that the closed system may reduce the risk of nosocomial infections in patients requiring arterial pressure monitoring.

Adult↗
PubMed1989

Caveat emptor: how to evaluate products.

1. The first two questions to consider when evaluating a product are: will it provide better patient care, and will it save time? 2. The cost effectiveness of the product is also an important consideration in addition to how well it will protect healthcare personnel. 3. Carefully examine the data supplied to support the product's efficacy, particularly the methods of studies. 4. Above all, common sense and experience are the best guides to product evaluation.

Equipment and Supplies, Hospital↗