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Biomedical subjects

D J Lanska

Publications and source records attributed to D J Lanska.

At least 55 records · Page 3Linked to original sources
PubMed1999

Epidemiology of human immunodeficiency virus infection and associated neurologic illness.

Worldwide, 30 million people are infected with the human immunodeficiency virus (HIV), with almost 6 million new infections in 1997. Recent therapeutic advances, which have altered the natural history of HIV infection, and changes in the AIDS case definition, both complicate evaluations of temporal changes in AIDS incidence and prevalence, and lesson the utility of AIDS incidence as a proxy for monitoring the HIV epidemic. The highest AIDS incidence rates in the United States are in black men. Rates are increasing most quickly in women, minorities, and adolescents and young adults, largely due to heterosexual transmission and intravenous drug abuse. Survival after diagnosis of AIDS is associated most strongly with the initial AIDS-defining diagnosis, and patients with neurologic opportunistic infections or primary central nervous system (CNS) lymphoma have shorter survival periods. Neurological illnesses are the initial manifestation of AIDS in 7% to 20% of patients, but the frequency of neurologic complications increases over the course of the illness. The most common AIDS-defining opportunistic illnesses are HIV encephalopathy, CNS toxoplasmosis, cytomegalovirus retinitis, and primary CNS lymphoma. Primary prevention of HIV infection is accomplished by changing factors that enable transmission, through behavioral changes, utilization of antiretroviral agents to prevent vertical transmission, and through securing the safety of the blood supply. Secondary prevention, involving early detection and prompt treatment, has become important in developed countries since the introduction of powerful antiretroviral therapies and has contributed to the 46% decline in AIDS deaths in the United States from 1996 to 1997. Inequality of access to effective therapies and emergence of multi-drug-resistant strains of HIV have raised serious concerns.

Central Nervous System Diseases↗
PubMed1999

Limitations of occupational air contaminant standards, as exemplified by the neurotoxin N-hexane.

Available industry guidelines and federal standards have failed to fully protect workers from chemical toxicity: none exist for most chemicals, many are biased toward what can easily be achieved, and many were developed long after health consequences became evident. Limitations of occupational air contaminant standards in the United States are well illustrated by standard-setting for the neurotoxin n-hexane. In the 1940s, the American Conference of Governmental Industrial Hygienists (ACGIH) first promulgated industrial guidelines known as "threshold limit values" (TLVs), including an 8-hour time-weighted average of 500 ppm for inspired n-hexane. Despite subsequent recognition of the neurotoxicity of n-hexane with industrial outbreaks of polyneuropathy beginning in the 1960s, the TLV for n-hexane remained unchanged until 1976 when a value of 100 ppm was adopted. Because a growing number of clinical reports have identified clinical and subclinical neurotoxicity from n-hexane near, at, and below the current time-weighted average TLV of 50 ppm, even this level is too high to protect all workers. In part due to procedural and political constraints, the Occupational Safety and Health Administration (OSHA) has independently developed only a small number of exposure standards in the past 25 years, and has been incapable of providing needed revisions for existing standards. Most OSHA standards--including those for n-hexane--were adopted in 1971 from the 1968 ACGIH TLVs and have never been revised. From 1971 to 1989 the OSHA permissible exposure level (PEL) for n-hexane remained at 500 ppm, 5-10 times as great as other contemporary standards. To help correct its regulatory backlong, OSHA promulgated 375 new or revised PELs in 1989--including a new standard of 50 ppm for n-hexane--but all of these were vacated by the 11th U.S. Court of Appeals in 1992. As a result, the current OSHA PEL for n-hexane remains at the 500 ppm level adopted in 1971, which even then was too high based upon available scientific evidence. New information over this long period, including that obtained from industrial outbreaks of disease due to chemical exposures, has not been incorporated into revised federal standards.

Adhesives↗
PubMed1998

[History of the reflex hammer].

The knee jerk was first described by Erb and Westphal in 1875. In subsequent years neurologists used direct finger taps and light-weight chest percussion hammers, but these proved to be inadequate for eliciting muscle stretch reflexes. The first hammer specially designed for eliciting such reflexes was the triangular reflex hammer introduced by John Madison Taylor in 1888. Over the next 25 years several popular reflex hammers were designed, some of which are still in use. These include the Babinski hammer with a round head fixed perpendicular to the shaft, and Rabiner's modification where the head can also be attached parallel to the shaft.

History, 19th Century↗
PubMed1998

Late-onset sporadic progressive subcortical gliosis.

We report two sporadic cases of progressive subcortical gliosis (PSG) with onset after age 60. The presentation included slowly progressive dementia with memory loss, geographic disorientation, and personality change. Both were diagnosed clinically as Alzheimer's disease (AD) and both met NINCDS-ADRDA criteria for probable AD. Autopsy revealed generalized atrophy, predominantly involving the white matter of the frontal and temporal lobes. Microscopically, prominent fibrillary astrocytosis was present in the subcortical white matter and in the subpial and deep layers of the overlying cerebral cortex. Mild cortical neuron loss accompanied the gliosis, but no myelin loss was evident. Amyloid deposits and neuronal cytoskeletal inclusions were absent.

Aged↗
PubMed1998

Dementia mortality in the United States. Results of the 1986 National Mortality Followback Survey.

This study sought to determine nationally representative estimates of mortality from or with dementia in the United States, to compare rates derived from various sources of ascertainment, and to estimate the contribution of dementia to morbidity and facility usage in the last year of life. National Mortality Followback Survey (NMFS) data were analyzed. The NMFS is based on a nationwide probability sample of persons aged 25 and over who died in the United States in 1986. For sampled decedents, information was obtained from death certificates, detailed questionnaires and interviews of family members, and from abstracted records of health facilities that provided care during the last year of life. Rates varied by age, race, and source of ascertainment. Rates based on death certificate diagnoses were generally an order of magnitude smaller than rates based on other sources. Alzheimer's disease was the most frequently reported cause of dementia. In the last year of life, most demented patients required assistance with multiple basic activities of daily living, had severe impairments in cognitive functioning, and received some care in general medical-surgical hospitals. Dementia is an extremely common cause of morbidity and mortality. Rates vary widely depending on the method of ascertainment; in particular, ascertainment based on death certificates grossly underestimates the magnitude of the problem.

Adult↗
PubMed1998

In-hospital mortality following carotid endarterectomy.

OBJECTIVES: To determine population-based estimates of in-hospital mortality following carotid endarterectomy (CEA) and identify potential risk factors for in-hospital death. METHODS: Data from the Healthcare Cost and Utilization Project (HCUP-3) were analyzed for the year 1993. Nationally representative estimates of risk were calculated by age, sex, race, income, census region, hospital location (urban versus rural), teaching status of hospital, number of hospital beds, hospital ownership, third-party payer, principal procedure, and presence of surgical complications. Multivariate models were developed using stepwise logistic regression and a logit model fit by generalized estimating equations. RESULTS: There were 228 deaths among 18,510 CEAs performed in 17 states of the United States in 1993, yielding an estimated in-hospital mortality rate of 1.2%. Multivariate analysis showed that age, principal procedure, and presence of any surgical complication were significant predictors of in-hospital mortality. Mortality increased with increasing age (from 0.9% in those younger than 65 years to 1.7% in those age 75 and older) and was markedly higher with CEA performed as a secondary procedure (6.1% versus 0.9%) or with any surgical complication (5.9% versus 0.9%). CONCLUSIONS: Increasing age, CEA performed as a secondary procedure, and surgical complications are important predictors of in-hospital mortality following CEA.

Aged↗
PubMed1998

Stroke and intracranial venous thrombosis during pregnancy and puerperium.

OBJECTIVES: To determine nationally representative estimates of the incidence of stroke and intracranial venous thrombosis during pregnancy and the puerperium, and to identify potential risk factors for these conditions. METHODS: National Hospital Discharge Survey data were analyzed for the period 1979 to 1991. Nationally representative estimates of risk were calculated by age, race, presence of pregnancy-related hypertension, census region, hospital ownership, and number of hospital beds. Multivariate models were developed using logistic regression. RESULTS: There were an estimated 8,918 cases of stroke and 5,723 cases of intracranial venous thrombosis during pregnancy and the puerperium in the United States among 50,264,631 deliveries, giving risks of 17.7 cases of stroke and 11.4 cases of intracranial venous thrombosis per 100,000 deliveries. In the multivariate models, stroke was associated strongly with pregnancy-related hypertension, larger hospital size, and proprietary hospital ownership, and inversely associated with living in the South. Intracranial venous thrombosis was associated with maternal age. CONCLUSIONS: Stroke and intracranial venous thrombosis are relatively common complications of pregnancy and the puerperium. Collectively, rates for these conditions are about 50% greater for the entire period of pregnancy and the puerperium than for the immediate peripartum period.

Adolescent↗
PubMed1998

The role of clinical pathways in reducing the economic burden of stroke.

Clinical pathways are a potentially beneficial, but largely untested, management strategy for both improving healthcare efficiency and decreasing costs while also maintaining or improving quality of care. Although relatively few clinical pathways for stroke have been described in the medical literature and although the reported benefits have been mixed, more and more hospitals are adopting clinical pathways as a management strategy for patients with stroke. In published clinical pathways for acute stroke, the following benefits have been reported: (i) reduced use of expensive diagnostic studies; (ii) fewer complications (particularly the frequency of urinary tract infections and aspiration pneumonia); (iii) reduced duration of hospital stay; (iv) reduced patient charges; and (v) lower mortality. However, these reported benefits are not consistent across all studies and some outcomes are highly correlated. Despite potential benefits, many clinical pathway programmes fail because of inadequate planning and shortcomings of implementation. Effective implementation of clinical pathways requires strong administrative and medical staff leadership, active participation of all clinical disciplines involved in the care of patients on the pathway, provision of regular feedback to clinicians, sufficient resources, improved documentation, incorporation of the entire episode of care into the pathway, integration with ongoing quality and utilisation management programmes, and periodic evaluation and modification.

Cerebrovascular Disorders↗
PubMed1998

The mad cow problem in the UK: risk perceptions, risk management, and health policy development.

Mad cow disease or bovine spongiform encephalopathy (BSE) is a fatal neurological disease of cattle first recognized in the United Kingdom (UK) in 1986. Until recently, the UK government considered the chance of a human becoming infected with the BSE agent to be extremely remote. As a result of new developments, alarmist media attention, bureaucratic mishandling of the issues, scientific uncertainty, bickering among technical experts, and a dearth of easily assimilated and balanced information on the problem, widespread fears that affected cattle could enter the human food supply and transmit the disease to humans have periodically erupted, causing social, economic, and political consequences of tremendous magnitude. Better management of the mad cow problem could have minimized the magnitude of the epidemic among cattle, the risk to humans, and the public outrage. Trust in the British government was seriously eroded, an entire industry crippled, and international relations severely tried. Although the scientific data concerning BSE and its transmissibility to humans are still not conclusive, a growing body of (still largely circumstantial) evidence suggests that BSE may be transmissible to humans. Unfortunately, policy decisions cannot wait for a final scientific answer. Therefore, high-stakes decisions must be made in the face of this uncertainty. Such decisions should be made with the primary purpose of protecting the public, and not preferentially the economics of an industry, political alliances, or other considerations. Given that the risk to humans from BSE was (and still is) unknown and may be high, and that the perceived risk among the British public was (and still is) extraordinarily high, policies should support more aggressive interventions. Of necessity, such interventions will be preventive, as there is presently no available treatment. Such policies should be modified as necessary as the developing scientific data warrants.

Animals↗
PubMed1997

The geographic distribution of Parkinson's disease mortality in the United States.

PURPOSE: This study examines geographic variation in reporting of Parkinson's disease mortality in the U.S. METHODS: National Center for Health Statistics and Bureau of the Census data were used to map age-adjusted, race- and race-gender-specific Parkinson's disease mortality rates in the U.S. for 1988. RESULTS: Among whites, high underlying-cause rates predominated in the North and low rates predominated in the South, whereas high contributing and all-cause rates were concentrated in the northeastern U.S. Strong north-to-south decreasing gradients were present for both underlying- and all-cause rates for whites, regardless of gender, whereas a clear west-to-east gradient could not be demonstrated. Geographic variation in contributing- and all-cause rates was partially explained by variation in tendency to report contributing causes of death. Reported rates among blacks were significantly lower than among whites. There was no latitudinal or longitudinal gradient of underlying-cause rates for blacks, but there was a relatively weak north-to-south decreasing gradient of all-cause rates for blacks, regardless of gender. CONCLUSIONS: The large-scale pattern of underlying-cause Parkinson's disease mortality among whites has persisted for over three decades.

Black or African American↗
PubMed1997

Comparison of utilization of Sinemet and Parkinson's disease mortality as surrogate indicators of Parkinson's disease in the United States.

OBJECTIVE: To compare two surrogate indicators of population disease burden for Parkinson's disease: utilization of Sinemet and Parkinson's disease mortality. DESIGN: National Center for Health Statistics data were used to tabulate Parkinson's disease mortality in the United States by state for 1987-1989. Sinemet sales data by state were obtained from Merck & Co., Inc. for 1988. Least squares regression analyses were used to assess the relationship between Sinemet utilization and Parkinson's disease mortality. SETTING: United States. RESULTS: Regression analyses showed extraordinarily strong associations between state-level Parkinson's disease mortality and Sinemet utilization (underlying-cause model r2 = 0.969, p = 0.0001; multiple-cause model r2 = 0.980, p = 0.0001). CONCLUSIONS: Sinemet utilization very closely parallels Parkinson's disease mortality, suggesting that Sinemet utilization and Parkinson's disease mortality are both useful indices of the population burden of Parkinson's disease for large-scale epidemiological studies.

Antiparkinson Agents↗
PubMed1997

Peripartum stroke and intracranial venous thrombosis in the National Hospital Discharge Survey.

OBJECTIVES: To determine nationally representative estimates of the incidence of peripartum stroke and intracranial venous thrombosis and to identify potential risk factors for these conditions. METHODS: We analyzed National Hospital Discharge Survey data for the period 1979-1991. Nationally representative estimates of risk were calculated by age, race, method of delivery, presence of pregnancy-related hypertension, census region, hospital ownership, and number of hospital beds. Multivariate models were developed using logistic and Poisson regression. RESULTS: There were an estimated 5484 cases of peripartum stroke and 4454 cases of intracranial venous thrombosis in the United States among 50,110,949 deliveries (risk, 10.3 cases of peripartum stroke and 8.9 cases of intracranial venous thrombosis per 100,000 deliveries). In both univariate and multivariate models, peripartum stroke was associated strongly with cesarean delivery, pregnancy-related hypertension, proprietary hospital ownership, and larger hospital size. Intracranial venous thrombosis was strongly associated with cesarean delivery and less strongly with smaller hospital size. CONCLUSIONS: Peripartum stroke and intracranial venous thrombosis are common complications of pregnancy. Although the associations identified in this study are plausible, further studies are required to confirm these associations and elucidate the underlying mechanisms.

Adolescent↗
PubMed1997

Geographic distribution of stroke mortality among immigrants to the United States.

BACKGROUND AND PURPOSE: This study examines the geographic distribution of stroke mortality among immigrants and natives of the United States. METHODS: National Center for Health Statistics and Bureau of the Census data were used to determine the geographic distribution of age-adjusted, race-, and race/sex-specific stroke mortality rates among immigrants and natives of the United States for 1979 to 1981. RESULTS: For whites and blacks and for each of the respective race/sex groups, immigrants had markedly and highly statistically significantly lower age-adjusted stroke mortality rates than either the entire US-born resident population or the US-born interregional migrant population. The spatial pattern of immigrant rates did not parallel the patterns for US-born populations. Immigrant rates were highest in the West and lowest in the Midwest for whites and highest in the Midwest and lowest in the Northeast for blacks, whereas for both US-born whites and blacks, resident and native rates were highest in the South and lowest in the Midwest. With few exceptions, region-specific immigrant rates for whites and blacks were significantly lower than rates for either US-born regional residents, US-born migrants to the regions, or US-born natives of the regions. In contrast, white immigrants to the West had significantly higher rates than US-born groups in that region. CONCLUSIONS: Selection factors strongly influence stroke mortality rates among immigrants to the United States. The aberrantly high rates among white immigrants to the West may in part reflect a bias due to large census undercounts of this population.

Adult↗
PubMed1997

Benign paroxysmal positioning vertigo: classic descriptions, origins of the provocative positioning technique, and conceptual developments.

The original description of benign paroxysmal positioning vertigo (BPPV) has been variously attributed to Bárány, Adler, and others. In addition, the proper eponymic designation for the provocative positioning test used to diagnose BPPV has been unclear, because authors use a variety of different terms, including Bárány, Nylén-Bárány, Nylén, Hallpike, Hallpike-Dix, and Dix-Hallpike to refer to the procedure in current use. Based on a review of the extant medical literature, Bárány was the first to describe the condition in detail, and Dix and Hallpike were the first to clearly describe both the currently used provocative positioning technique and the essential clinical manifestations of benign paroxysmal positioning vertigo elicited by that technique. Nevertheless, despite their important contributions, neither Bárány nor Dix and Hallpike understood the pathophysiology of BPPV nor did they appreciate that the positioning techniques they used actually demonstrated pathology in the semicircular canals rather than the utricle. The modern understanding of the pathophysiology of BPPV began with Schuknecht's proposal that the dysfunction resulted from the gravity-dependent movement of loose or fixed dense material within the posterior semicircular canal ("cupulolithiasis"). Although Schuknecht's formulations were not consistent with all clinical features of the disease, they led to the modern "canalolithiasis theory" and highly effective canalith repositioning or "liberatory" maneuvers for BPPV.

History, 20th Century↗