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L Middleton

Publications and source records attributed to L Middleton.

At least 37 records · Page 2Linked to original sources
PubMed1992

Detection of Duchenne and Becker muscular dystrophy carriers by quantitative multiplex polymerase chain reaction analysis.

We developed a method for the detection of Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) carriers. The method is based on the quantitative analysis of the products of standard multiplex polymerase chain reaction (PCR) from 18 different exons of the dystrophin gene, and is designated "QM-PCR." We detected deletions of one or more exons by standard multiplex PCR in DMD/BMD patients in 14 of 18 families examined (77.7%). The same deletions were readily demonstrated by QM-PCR in nine of 14 mothers (64.3%) and in another six of 22 possible carriers in these families. In five families where deletions were detectable in DMD/BMD patients, the mothers did not exhibit any deletions in their peripheral blood (35.7%). We obtained evidence for germinal mosaicism in at least two of these families and confirmed carrier identification by haplotype analysis using CA repeat polymorphisms at the 5' and 3' ends of the dystrophin gene. Furthermore, analysis of 17 coded DNA samples from normal females and obligatory carriers by QM-PCR showed that this technique could directly identify carriers of deletions in any of 18 different exons of the dystrophin gene. Its application in combination with existing techniques is expected to significantly improve the accuracy of carrier diagnosis in many families, and it may also be applicable to families in which pedigree and polymorphism information is insufficient for carrier diagnosis.

Exons↗
PubMed1992

High-risk sexual behavior and condom use among gay and bisexual African-American men.

OBJECTIVES: Little is known about the human immunodeficiency virus (HIV) high-risk sexual practices of gay and bisexual African-American men. These data are needed so that better interventions can be developed and implemented in this population. METHODS: The frequency and correlates of unprotected anal intercourse were examined among 250 gay and bisexual African-American men in the San Francisco Bay Area. The cohort was recruited in 1990 from bars, bathhouses, and erotic bookstores, and through African-American gay organizations, street outreach, advertisements in gay mainstream and African-American newspapers, health clinics, and personal referral from other participants. RESULTS: More than 50% of the men in our sample reported having unprotected anal intercourse in the past 6 months, a considerably higher percentage than that among gay White men in San Francisco through 1988 and 1989. Men who practiced unprotected anal intercourse were more likely to be poor, to have been paid for sex, or to have used injection drugs; to have a higher perceived risk of HIV infection; and to report less social support for concerns about risky sexual behavior. Condom norms, condom efficacy, and negative expectations about using condoms predicted these men's failure to use them. CONCLUSION: In the second decade of the acquired immunodeficiency syndrome epidemic, risk reduction programs are still needed for gay and bisexual African-American men.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Do general practitioners promote health? A needs assessment.

A random sample of 5% of NSW general practitioners was surveyed in December 1986 regarding their attitudes to health promotion in clinical practice. The results were compared with those of simultaneous surveys of trainee general practitioners and fourth-year medical students. Smoking, alcohol and weight reduction were the health behaviours that were considered by general practitioners to be the most difficult to change. More general practitioners than did students or general-practitioner trainees reported finding less difficulty in changing health behaviours. More than three-quarters of the general practitioners were in favour of promoting health in their practices. A commonly reported barrier was the current Medicare financing arrangements for preventive practice. Other barriers included a lack of time for preventive practice. The complaint of a lack of training was expressed commonly; half the sample was willing to participate in advanced training in health promotion that would be organized by The Royal Australian College of General Practitioners.

Adult↗
PubMed1989

Molecular genetics of amyloid neuropathy in Europe.

The Portuguese type of familial amyloid polyneuropathy (FAP type I), a disabling autosomal dominant disorder with onset in early adult life, is caused by a point mutation in the transthyretin (TTR; previously known as prealbumin) gene. DNA analysis in thirteen European families (one British, two French, one Italian, one Greek, and eight Cypriot) showed that members of all those from Cyprus and Greece, and one from France, carried the FAP type I mutation. Patients from seven of these ten kindreds were not known to have a genetic disease before this study, which demonstrated the mutation in 16 of 43 clinically unaffected relatives. 2 of these were aged over 50 years. TTR gene analysis has useful applications in genetic counselling, including prenatal diagnosis, in identifying the cause of seemingly sporadic cases of amyloid neuropathy, and in epidemiological studies of FAP.

Adult↗
PubMed1989

Focal cranial nerve involvement in chronic inflammatory demyelinating polyneuropathy: clinical and MRI evidence of peripheral and central lesions.

Five cases of chronic inflammatory demyelinating polyneuropathy are described in which cranial nerve involvement accompanied a more generalized neuropathy. Clinical, electrophysiological, radiological and nerve biopsy findings are presented. Cranial nerve lesions in this form of polyneuropathy may be related to lesions of the peripheral nerves or of the central nervous system, when they may be accompanied by MRI evidence of more widespread CNS demyelinating lesions. In cases of early onset, the occurrence of focal cranial nerve lesions may serve to distinguish chronic inflammatory from inherited demyelinating polyneuropathies.

Adolescent↗
PubMed1988

Comparative electrophysiologic evaluation of nerve grafts and autogenous vein grafts as nerve conduits: an experimental study.

This study was carried out to compare electrophysiologically the efficacy of autogenous vein grafts, with autogenous nerve grafts as conduits for nerve regeneration. A 0.75-cm segment of sciatic nerve was resected in two groups of Sprague-Dawley rats of equivalent maturity. The nerve gaps were bridged with an autogenous vein graft in the first group (31 rats), and an autogenous nerve graft in the second group (24 rats). Serial in vivo nerve conduction velocity studies and terminal in vitro nerve conduction velocity and nerve action potential measurements were performed. An additional group of 21 animals who had undergone no surgical procedures, were similarly studied to establish an age-adjusted baseline for comparison. Twelve animals in the first group, 14 in the second group, and 13 in the baseline group survived the full year of study. In vivo conduction velocities between the two experimental groups compared favorably. Nerve conduction velocity determined by in vitro technique confirmed this finding and measured similarly at about 78 percent of the baseline. Nerve action potential amplitude in the vein-grafted group was 12.0 percent of the baseline, while the nerve-grafted group was 23.9 percent of the baseline. This study demonstrated that the vein graft compares well with the nerve graft in nerve conduction velocity, but only one-half as well in nerve action potential.

Action Potentials↗
PubMedDate not supplied

Ultrastructural diagnosis of mitochondrial encephalomyopathies revisited.

Mitochondrial encephalomyopathies (MEs) are a heterogeneous group of multisystem disorders with extreme variability in clinical phenotype. Due to their complex nature, accurate diagnosis requires a coordinated approach, based on clinical and various laboratory data. Despite the introduction of biochemical assay of mitochondrial enzymes and the availability of mtDNA mutation analysis, the diagnosis of MEs still relies heavily on morphological methods. The latter include histology, histochemistry, and electron microscopy. A comparative study was undertaken to define the contemporary role of electron microscopy in the morphological diagnosis of MEs. Muscle biopsies from 20 patients with MEs, 9 children and 11 adults, were evaluated by histology, enzyme histochemistry, and electron microscopy. The results clearly demonstrate that electron microscopy is of importance in providing essential diagnostic information in pediatric patients, but is of lesser value in the diagnosis of adult cases, where it provides only supplementary information.

Adult↗
PubMedDate not supplied

The role of electron microscopy in the diagnosis of nonneoplastic muscle diseases.

Accurate diagnosis of muscle disease is dependent on a careful clinical examination followed by the appropriate laboratory investigations, which in a contemporary diagnostic center should also include ultrastructural investigations. As is the case in other tissues, the interpretation of the ultrastructural abnormalities observed in muscle must take into consideration several factors, in particular the small sample size, possible artifacts, and the nonspecificity of changes. Despite the fact that the majority of ultrastructural changes seen in muscle are not specific, electron microscopic examination still provides important and unique clues regarding patterns of change that characterize certain disease entities. Since this detailed ultrastructural information cannot at present be obtained by any other means, it is anticipated that electron microscopy will still play a vital role in the diagnosis of the nonneoplastic muscle diseases, well into the twenty-first century.

Humans↗