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Biomedical subjects

L Lockhart

Publications and source records attributed to L Lockhart.

At least 19 recordsLinked to original sources
PubMed2002

Comparative study to evaluate skin irritation and adhesion of Estradot and Climara in healthy postmenopausal women.

OBJECTIVES: To compare the local tolerability, adhesion and estradiol delivery of a 5-cm(2) transdermal patch (Estradot), Novartis Pharmaceuticals, Basel, Switzerland) and a 12.5-cm(2) patch (Climara, Berlex Laboratories, Wayne, NJ, USA). METHODS: This was an open-label, randomized, intrapatient, comparative study. One hundred healthy postmenopausal women applied the 50 micro g/day 5-cm(2) patch and the 12.5-cm(2) patch concurrently for 7 days; safety and tolerability were assessed. Twelve women continued to apply the 5-cm(2) and 12.5-cm(2) patches separately for 7 days in a two-way cross-over study, to investigate the reproducibility of estradiol delivery. RESULTS: The proportion of subjects with a clinically significant erythema score was higher with the 12.5-cm(2) patch. The 5-cm(2) patch had a significantly lower incidence of very slight erythema than the larger patch (21.4% vs. 32.3%; p = 0.0028). Overall erythema scores were 0.22 and 0.41, respectively. More 5-cm(2) patches had > 90% adherence than the 12.5-cm(2) patches (87.5% vs. 82.0%, not significant) and fewer became detached (0.5% vs. 3.0%). Both the patches showed reproducible delivery of estradiol. CONCLUSION: The 5-cm(2) patch was associated with less skin irritation and better adherence than the 12.5-cm(2) patch, although the majority of the differences were not significant. The 5-cm(2) patch was well tolerated and showed reproducible estradiol delivery, as did the 12.5-cm(2) patch.

Adhesiveness↗
PubMed2001

Myocardial infarction in men and women under 65 years of age: no evidence of gender bias.

We examined short and long term outcomes of MI in a consecutive series of 169 men and 50 women who were followed for an average of 3.5 years. Similar percentages of men and women were admitted to medical intensive care, received in-patient cardiac rehabilitation, quit smoking at one year, were still smoking, were taking a lipid lowering drug or had returned to work at one year, underwent coronary angiography at 3.5 years or had died by 3.5 years. The lack of gender difference in outcome may reflect an absence of gender bias in the management of men and women with MI in southwest Scotland.

Age Factors↗
PubMed2000

First comprehensive low-density horse linkage map based on two 3-generation, full-sibling, cross-bred horse reference families.

Two 3-generation full-sibling reference families have been produced and form a unique resource for genetic linkage mapping studies in the horse. The F(2) generations, now comprising 61 individuals, consist of 28- to 32-day-old embryos removed nonsurgically from two pairs of identical twin mares. The same stallion sired all F(2)s such that the two full-sibling families are half-sibling with respect to each other. The families are crossbred to maximize levels of heterozygosity and include Arabian, Thoroughbred, Welsh Cob, and Icelandic Horse breeds. Milligram quantities of DNA have been isolated from each embryo and from blood samples of the parents and grandparents. The families have been genotyped with 353 equine microsatellites and 6 biallelic markers, and 42 linkage groups were formed. In addition, the physical location of 85 of the markers is known, and this has allowed 37 linkage groups to be anchored to the physical map. The inclusion of dams in the genotyping analysis has allowed the generation of a genetic map of the X chromosome. Markers have been assigned to all 31 autosomes and the X chromosome. The average interval between markers on the map is 10.5 cM, and the linkage groups collectively span 1780 cM. The results demonstrate the benefits for horse linkage mapping studies of genotyping on these unique full-sibling families, which comprise relatively few individuals, by the generation of a comprehensive low-density map of the horse genome.

Animals↗
PubMed1999

Spatial and temporal trends and effects of contaminants in the Canadian Arctic marine ecosystem: a review.

Recent studies have added substantially to our knowledge of spatial and temporal trends of persistent organic pollutants and heavy metals in the Canadian Arctic marine ecosystem. This paper reviews the current state of knowledge of contaminants in marine biota in the Canadian Arctic and where possible, discusses biological effects. The geographic coverage of information on contaminants such as persistent organochlorines (OCs) (PCBs, DDT- and chlordane-related compounds, hexachlorocyclohexanes, toxaphene) and heavy metals (mercury, selenium, cadmium, lead) in tissues of marine mammal and sea birds is relatively complete. All major beluga, ringed seal and polar bear stocks along with several major sea bird colonies have been sampled and analysed for OC and heavy metal contaminants. Studies on contaminants in walrus are limited to Foxe Basin and northern Québec stocks, while migratory harp seals have only been studied recently at one location. Contaminant measurements in bearded seal, harbour seal, bowhead whale and killer whale tissues from the Canadian Arctic are very limited or non-existent. Many of the temporal trend data for contaminants in Canadian Arctic biota are confounded by changes in analytical methodology, as well as by variability due to age/size, or to dietary and population shifts. Despite this, studies of OCs in ringed seal blubber at Holman Island and in sea birds at Prince Leopold Island in Lancaster Sound show declining concentrations of PCBs and DDT-related compounds from the 1970s to 1980s then a levelling off during the 1980s and early 1990s. For other OCs, such as chlordane, HCH and toxaphene, limited data for the 1980s to early 1990s suggests few significant declines in concentrations in marine mammals or sea birds. Temporal trend studies of heavy metals in ringed seals and beluga found higher mean concentrations of mercury in more recent (1993/1994) samples than in earlier collections (1981-1984 in eastern Arctic, 1972-1973 in western Arctic) for both species. Rates of accumulation of mercury are also higher in present day animals than 10-20 years ago. Cadmium concentrations in the same animals (eastern Arctic only) showed no change over a 10-year period. No temporal trend data are available for metals in sea birds or polar bears. There have been major advances in knowledge of specific biomarkers in Canadian Arctic biota over the past few years. The species with the most significant risk of exposure to PCBs and OC pesticides may be the polar bear which, based on comparison with EROD activity in other marine mammals (beluga, ringed seal), appears to have elevated CYP1A-mediated activity. The MFO enzyme data for polar bear, beluga and seals suggest that even the relatively low levels of contaminants present in Arctic animals may not be without biological effects, especially during years of poor feeding.

Animals↗
PubMed1999

Spatial and temporal trends of contaminants in Canadian Arctic freshwater and terrestrial ecosystems: a review.

The state of knowledge of contaminants in Canadian Arctic biota of the freshwater and terrestrial ecosystems has advanced enormously since the publication of the first major reviews by Lockhart et al. and Thomas et al. in The Science of the Total Environment in 1992. The most significant gains are new knowledge of spatial trends of organochlorines and heavy metal contaminants in terrestrial animals, such as caribou and mink, and in waterfowl, where no information was previously available. Spatial trends in freshwater fish have been broadened, especially in the Yukon, where contaminant measurements of, for example, organochlorines were previously non-existent. A review of contaminants data for fish from the Northwest Territories, Yukon and northern Quebec showed mercury as the one contaminant which consistently exceeds guideline limits for subsistence consumption or commercial sale. Lake trout and northern pike in the Canadian Shield lakes of the Northwest Territories and northern Quebec generally had the most elevated levels. Levels of other heavy metals were generally not elevated in fish. Toxaphene was the major organochlorine contaminant in all fish analyzed. The concentrations of organochlorine contaminants in fish appear to be a function not only of trophic level but of other aspects of the lake ecosystem. Among Arctic terrestrial mammals, PCBs and cadmium were the most prominent contaminants in the species analyzed. Relatively high levels (10-60 micrograms g-1) of cadmium were observed in kidney and liver of caribou from the Yukon, the Northwest Territories and northern Quebec, with concentrations in western herds being higher than in those from the east. For the organochlorine contaminants, a west to east increase in zigma PCBs, HCB and zigma HCH was found in caribou, probably as a result of the predominant west to east/north-east atmospheric circulation pattern which delivers these contaminants from industrialized regions of central and eastern North America to the Arctic via long-range atmospheric transport. Radiocesium contamination of lichens and caribou has continued to decrease. Significant contamination by PCBs and lead of soils and vascular plants was observed in the immediate vicinity and within a 20-km radius of DEW line sites in the Canadian Arctic. There was also evidence for transfer of PCBs from plants to lemmings. There was no evidence, however, that large mammals such as caribou living in the general area of the DEW line sites had elevated levels of PCBs. There is very limited temporal trend information for most contaminants in biota of Arctic terrestrial and freshwater environments.

Animals↗
PubMed1999

Comparative irritancy study among retinoid creams and gels.

BACKGROUND: Topical retinoids, although very useful in dermatology, may be irritating to some patients. OBJECTIVE: There are a number of topical retinoids available in Canada, and the objective of the present study was to evaluate the irritancy potential in humans of retinoid gels and creams presently available in Canada. METHODS: Thirty healthy adults were administered 10 products (five creams, three gels, petrolatum, and sodium lauryl sulfate (SLS) 0.1% w/v) for up to 21 consecutive days. RESULTS: Early termination of patching due to irritation was required for the tretinoin creams and gels and SLS more frequently and earlier in the study than for adapalene and petrolatum (p =.001). Statistically significant, among-group differences were noted in the severity of irritation at each day and for the cumulative score for both the creams and the gels (p =.0001), in favour of adapalene over the tretinoin products. CONCLUSION: By several measures, adapalene cream and gel were less irritating upon multiple dosing than various tretinoin creams and gels.

Adapalene↗
PubMed1990

National Data Bank to revolutionize peer review reporting.

In addition to state-mandated reporting requirements, hospitals and other health care entities soon must comply with the reporting requirements of the Health Care Quality Improvement Act, as implemented by Health and Human Services regulations. The regulations require reporting (1) adverse peer review and licensure actions involving physicians and dentists; and (2) malpractice claims payments involving physicians, dentists or other health care practitioners. Otherwise, reporting on other health care practitioners is voluntary. Hospitals must request information from the Data Bank about applicants for medical staff appointment or privileges and must review Data Bank information about practitioners on staff every two years thereafter. Hospitals must have policies and procedures for requesting such information.

Databases, Factual↗
PubMed1990

Needs assessment for genetic services in Texas.

In summary, we found that the availability of genetic services for the Medicaid patients with the 11 selected disorders follow the general population distribution for Texas. In general, there is no major geographic factor limiting availability of services. We also found that the calculation of Medicaid dollars paid according to the size of the metropolitan area in which the patient resides indicates that there are fewer Medicaid dollars spent on these 11 genetic disorders per person in the population in the larger metropolitan areas. We conclude that preliminary review of these data indicate that the urban poor may have a greater need for medical services that deal with genetic disease.

Databases, Factual↗
PubMed1990

A study of medical costs associated with selected genetic disorders in Texas.

We estimated that the payments associated with the 11 selected diseases during 1987 in Texas included $88.2 million from Medicaid and $10.6 million from CIDC for a total of $98.8 million. Patients with these diseases represented 0.83% of Medicaid claims, but 4.68% of Medicaid payments. Medicaid payments for genetic services for patients with these 11 selected disorders in Texas during a nine-month period in 1987 were $10,122, or 0.02% of the total Medicaid payments for these claimants. We conclude that our estimate of the Medicaid payments for these disorders in 1987 of nearly $100 million represents a low estimate of the true medical costs for the care of these patients. This study also indicates that these 11 disorders represent a disproportionate share of Medicaid payments; i.e., these patients show a high ratio of payment per claim. We also conclude from these data that CIDC is a significant source of support for the medical care of these patients in Texas. And, finally, this study suggests that referral for genetic services represents a significant barrier for individuals in need of these services.

Child↗
PubMed1990

New peer review reporting and disclosure requirements--Part I.

This article reviews the reporting and disclosure provisions of the Health Care Quality Improvement Act of 1986, the Medicare and Medicaid Patient and Program Protection Act of 1987, the Texas Medical Practice Act, and federal regulations promulgated in late 1989 to establish the operating rules and policies of the National Practitioner Data Bank. A table on pages 56-57 outlines the reporting requirements of these laws and regulations. Discussion focuses on the requirements the new federal regulations place on physicians and other health care practitioners, health care entities, and insurers.

Humans↗