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Biomedical subjects

Richard Lewis

Publications and source records attributed to Richard Lewis.

13 recordsLinked to original sources
PubMed2003

Schwann cell expression of PLP1 but not DM20 is necessary to prevent neuropathy.

Proteolipid protein (PLP1) and its alternatively spliced isoform, DM20, are the major myelin proteins in the CNS, but are also expressed in the PNS. The proteins have an identical sequence except for 35 amino acids in PLP1 (the PLP1-specific domain) not present in DM20. Mutations of PLP1/DM20 cause Pelizaeus-Merzbacher Disease (PMD), a leukodystrophy, and in some instances, a peripheral neuropathy. To identify which mutations cause neuropathy, we have evaluated a cohort of patients with PMD and PLP1 mutations for the presence of neuropathy. As shown previously, all patients with PLP1 null mutations had peripheral neuropathy. We also identified 4 new PLP1 point mutations that cause both PMD and peripheral neuropathy, three of which truncate PLP1 expression within the PLP1-specific domain, but do not alter DM20. The fourth, a splicing mutation, alters both PLP1 and DM20, and is probably a null mutation. Six PLP1 point mutations predicted to produce proteins with an intact PLP1-specific domain do not cause peripheral neuropathy. Sixty-one individuals with PLP1 duplications also had normal peripheral nerve function. These data demonstrate that expression of PLP1 but not DMSO is necessary to prevent neuropathy, and suggest that the 35 amino acid PLP1-specific domain plays an important role in normal peripheral nerve function.

Adolescent↗
PubMed2003

Vinyl chloride and liver and brain cancer at a polymer production plant in Louisville, Kentucky.

Studies of overlapping cohorts in the United States have shown an excess mortality from brain cancer in vinyl chloride (VC)-exposed workers. One plant located in Louisville, Kentucky, is included in many of these studies. We separated this plant from the large US cohort and re-analyzed the mortality experience. Louisville experienced significantly elevated liver (standardized mortality analyses [SMR] = 400) and brain cancer (SMR = 229) mortality. Liver cancer mortality remained significantly elevated (SMR = 344) in the remaining cohort; however, brain cancer mortality was markedly reduced (SMR = 112) when Louisville was removed. In contrast with liver cancer, a preliminary review of work assignments did not suggest that the brain cancer excess was related to VC exposure. The Louisville brain cancer cluster has had a significant impact on the reported literature. Although unrelated to VC, the cause of this cluster remains uncertain.

Air Pollutants, Occupational↗
PubMed2003

A case-cohort study of angiosarcoma of the liver and brain cancer at a polymer production plant.

Past studies have reported an excess of angiosarcoma of the liver and brain cancer at a polymer production plant in Louisville, Kentucky. Although angiosarcoma has clearly been linked to vinyl chloride exposure, the cause of the brain cancer excess has been uncertain. We conducted case-cohort and case-control studies of both conditions in relation to chemicals used in polyvinyl chloride and nitrile rubber production. Angiosarcoma was strongly associated with vinyl chloride exposure but not with other chemicals used in production. Brain cancer was highest in workers hired prior to 1950 but was not associated with vinyl chloride or other specific exposures or production processes. This brain cancer cluster is similar to those reported in other industries in this generation of workers, the specific cause remaining unknown.

Aged↗
PubMed2003

Back to the market: yet more reform of the National Health Service.

Yet more reform of the National Health Service in England has been announced by the Department of Health. In opposition, the Labour Party criticized the creation of an "internal market" for health care by the Conservative government, but five years into the Blair administration, market incentives are to be reinvigorated and the private sector is to be embraced in ways not seen hitherto. New guidance signals the introduction of competitive contracting using cost-per-case currencies, more choice for patients in where they will receive hospital treatment, and the freeing of NHS care providers from the direct political control of ministers. It is intended that the monopolistic features of the NHS in England should give way to greater pluralism, in particular through contracts with privately owned health care organizations. However, there is little evidence to suggest that these policies will be effective, and a number of practical problems may obstruct implementation.

Competitive Bidding↗
PubMed2002

Organization and financing of British primary care groups and trusts: observations through the prism of US managed care.

There are many parallels between the UK's new primary care commissioning organizations and the managed care organizations and integrated delivery systems that have evolved in the USA over the last three decades. Those building primary care groups and trusts (PCG/Ts) can learn from the American experience with health maintenance organizations and other similar entities. These lessons should also be relevant to those in other countries interested in establishing innovative primary care led organizations within the broader structure of a socialized health care system. Following an overview of US managed care and an update of the progress of the UK's PCG/Ts, we go on to suggest how new consortia of PCG/Ts might be developed and how budgets and provider incentives could be structured. This international comparison suggests that the resources needed to support the development of effective PCG/Ts will be considerable, as will the need to maintain organizational flexibility. If primary care organizations are to thrive, it will be essential to develop truly integrated budgets for primary and secondary care.

Budgets↗