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Biomedical subjects

E Howell

Publications and source records attributed to E Howell.

At least 19 recordsLinked to original sources
PubMed2006

A case-crossover study of fine particulate matter air pollution and onset of congestive heart failure symptom exacerbation leading to hospitalization.

Persons with congestive heart failure may be susceptible to ambient air pollution. The authors evaluated the association between exposure to particulate matter with an aerodynamic diameter of <2.5 microm (PM2.5) and onset of symptom exacerbation leading to hospital admission in Baltimore, Maryland. They used a case-crossover design for 135 case events occurring among 125 persons with prevalent congestive heart failure who were admitted to a single hospital through the emergency department during 2002. The case period was assigned using three index times: 8-hour and 24-hour periods of symptom onset and date of hospital admission. Controlling for weather, the authors detected a modest relative increase in risk for cases defined by 8-hour symptom onset for an interquartile-range increase in PM2.5 at a 2-day lag (odds ratio=1.09, 95% confidence interval: 0.91, 1.30). A corresponding increase in risk was not observed when admission date was used to define the case period. A series of simulations based on study data indicated that the study had adequate statistical power to detect odds ratios of 1.2 or higher. Although overall findings were not statistically significant, the identification of case events defined by an 8-hour onset period may be more relevant than either a 24-hour onset period or the admission date for estimating harmful effects of air pollutant exposure on cardiovascular health.

Aged↗
PubMed2004

Aquatic snails from mining sites have evolved to detect and avoid heavy metals.

Toxicants in polluted environments are often patchily distributed. Hence, rather than being passive absorbers of pollution, some organisms have evolved the ability to detect and avoid toxicants. We studied the avoidance behavior of Physella columbiana, an aquatic pulmonate snail, in a pond that has been polluted with heavy metals for more than 120 years. Populations of this snail are rare at reference sites and are only robust at heavy-metal-polluted sites. We hypothesized that the snails are able to persist because they have evolved the ability to minimize their exposure to metals by actively avoiding metals in their environment. Using a Y-maze flow tank, we tested the avoidance behavior of snails to heavy-metal-polluted sediments and single-metal solutions of cadmium, zinc, or lead. We also tested the avoidance behaviors of the snails' laboratory-reared offspring raised in nonpolluted conditions. In addition, we tested the avoidance behavior of a small population of snails from a reference pond. Although all the snails we tested were able to detect low concentrations of heavy metals, we found that snails from the polluted site were the most sensitive, that their offspring were somewhat less sensitive, and that snails from the reference site were the least sensitive. This suggests that the ability of polluted-site snails to avoid heavy metals is both genetic and environmental. The concentrations of metals avoided by the snails from the polluted site were below the levels found at hot spots within their natal pond. The snails may be able to persist at this site because they decrease their exposure by moving to less-polluted sections of the pond. One application of our findings is the use of aquatic snails and our Y-maze design as an inexpensive pollution detector. Environmental pollutants such as lead, zinc, and arsenic are a problem throughout the world. People in underdeveloped countries often lack sophisticated pollution detection devices. We have developed a behavioral assay of aquatic pollution that is easy to use, is extremely sensitive (detection below 10 ppb), and can be constructed for fewer than 100 US dollars. Pulmonate snails are widely distributed in tropical, subtropical, and temperate parts of the globe, and they are often common in polluted waters. For countries such as India and Bangladesh, which must test thousands of shallow wells for possible contamination with heavy metals, our assay would be a good initial test. Once snails detected metals, then those samples could be confirmed by spectrometers. We encourage scientists in underdeveloped nations to consider our assay as an option.

Animals↗
PubMed2001

Vibrational structure of dihydrofolate bound to R67 dihydrofolate reductase.

R67 is a Type II dihydrofolate reductase (DHFR) that catalyzes the reduction of dihydrofolate (DHF) to tetrahydrofolate by facilitating the addition of a proton to N5 of DHF and the transfer of a hydride ion from NADPH to C6. Because this enzyme is a plasmid-encoded DHFR from trimethoprim-resistant bacteria, extensive studies on R67 with various methods have been performed to elucidate its reaction mechanism. Here, Raman difference measurements, conducted on the ternary complex of R67.NADP(+).DHF believed to be an accurate mimic of the productive DHFR.NADPH.DHF complex, show that the pK(a) of N5 in the complex is less than 4. This is in clear contrast to the behavior observed in Escherichia coli DHFR, a substantially more efficient enzyme, where the pK(a) of bound DHF at N5 is increased to 6.5 compared with its solution value of 2.6. A comparison of the ternary complexes in R67 and E. coli DHFRs suggests that enzymic raising of the pK(a) at N5 can significantly increase the catalytic efficiency of the hydride transfer step. However, R67 shows that even without such a strategy an effective DHFR can still be designed.

Folic Acid↗
PubMed2000

Cervical cancer practice patterns and appropriateness of therapy.

OBJECTIVE: This study was undertaken (1) to describe practice patterns for treatment of cervical cancer on a national scale, including patient characteristics associated with receiving appropriate versus inappropriate therapy, and (2) to determine whether mortality rate differences exist between patients who were treated appropriately and those who were treated inappropriately. STUDY DESIGN: We defined treatment appropriateness in cases of cervical cancer according to general recommendations for therapy for each International Federation of Gynecology and Obstetrics stage. In an analysis of data obtained from the Surveillance, Epidemiology, and End Results Program for 1988 through 1994 we determined the associations of patient demographic characteristics and tumor characteristics with treatment appropriateness. The association between treatment appropriateness and overall mortality for as long as 7 years of follow-up was adjusted for age; marital status; Surveillance, Epidemiology, and End Results Program location; International Federation of Gynecology and Obstetrics stage of disease; lymph node status; tumor grade; and histologic classification. RESULTS: Overall 90% of all patients were found to have received appropriate therapy. Important variables significantly associated with being treated inappropriately versus appropriately included age <40 years, positive nodal status, and International Federation of Gynecology and Obstetrics stage IB disease. Important variables significantly associated with receiving no therapy versus receiving appropriate therapy were age >/=60 years, International Federation of Gynecology and Obstetrics stage IV disease, positive nodal status, and unknown nodal status. In a comprehensive model that included demographic factors and tumor characteristics, the adjusted hazard ratio for mortality among patients who were treated inappropriately versus appropriately was 0.87 (95% confidence interval, 0.70-1.09). The adjusted hazard ratio for mortality among patients who did not receive therapy versus those who were treated appropriately was 2.92 (95% confidence interval, 2.44-3.48). CONCLUSIONS: In an analysis of data from a tumor registry, cervical cancer practice patterns were generally found to follow accepted treatment guidelines. Appropriateness of therapy did not vary widely according to demographic variables. Although patients who received no therapy had an elevated risk of death with respect to that of patients who were treated appropriately, patients who were treated inappropriately had a mortality rate similar to that among those who were treated appropriately (perhaps because of limitations in Surveillance, Epidemiology, and End Results Program data). Results of this preliminary study suggest a need for further research on effectiveness of cervical cancer therapies in the general population.

Adult↗
PubMed1999

Underascertainment of child abuse mortality in the United States.

CONTEXT: Mortality figures in the United States are believed to underestimate the incidence of fatal child abuse. OBJECTIVES: To describe the true incidence of fatal child abuse, determine the proportion of child abuse deaths missed by the vital records system, and provide estimates of the extent of abuse homicides in young children. DESIGN AND SETTING: Retrospective descriptive study of child abuse homicides that occurred over a 10-year period in North Carolina from 1985-1994. CASES: The Medical Examiner Information System was searched for all cases of children younger than 11 years classified with International Classification of Diseases, Ninth Revision codes E960 to E969 as the underlying cause of death and homicide as the manner of death. A total of 273 cases were identified in the search and 259 cases were reviewed after exclusion of fetal deaths and deaths of children who were not residents of North Carolina. MAIN OUTCOME MEASURE: Child abuse homicide. RESULTS: Of the 259 homicides, 220 (84.9%) were due to child abuse, 22 (8.5%) were not related to abuse, and the status of 17 (6.6%) could not be determined. The rate of child abuse homicide increased from 1.5 per 100000 person-years in 1985 to 2.8 in 1994. Of all 259 child homicides, the state vital records system underrecorded the coding of those due to battering or abuse by 58.7%. Black children were killed at 3 times the rate of white children (4.3 per 100000 vs 1.3 per 100000). Males made up 65.5% (133/203) of the known probable assailants. Biological parents accounted for 63% of the perpetrators of fatal child abuse. From 1985 through 1996, 9467 homicides among US children younger than 11 years were estimated to be due to abuse rather than the 2973 reported. The ICD-9 cause of death coding underascertained abuse homicides by an estimated 61.6%. CONCLUSIONS: Using medical examiner data, we found that significant underascertainment of child abuse homicides in vital records systems persists despite greater societal attention to abuse fatalities. Improved recording of such incidences should be a priority so that prevention strategies can be appropriately targeted and outcomes monitored, especially in light of the increasing rates.

Black or African American↗
PubMed1996

An assessment of surgery for spinal stenosis: time trends, geographic variations, complications, and reoperations.

OBJECTIVE: To study temporal trends and geographic variations in the use of surgery for spinal stenosis, estimate short-term morbidity and mortality of the procedure, and examine the likelihood of repeat back surgery after surgical repair. DESIGN: Cohort study based on Medicare claims. SETTING: Hospital care. SUBJECTS: All Medicare beneficiaries 65 years of age or older who received a lumbar spine operation for spinal stenosis in 1985 or 1989 were followed through 1991 (10,260 patients from the 1985 cohort and 18,655 from the 1989 cohort). MAIN OUTCOME MEASURES: Two outcomes were measured: (1) rates of operation for spinal stenosis by state and (2) on an individual level, operative complications (cardiopulmonary, vascular, or infectious), postoperative mortality, and time between first operation and any subsequent reoperation. RESULTS: Rates of surgery for spinal stenosis increased eightfold from 1979 to 1992 for patients aged 65 and older and varied almost fivefold among US states. Mortality and operative complications increased with age and comorbidity. Complications were more likely for men and for individuals receiving spinal fusions. The 1989 cohort experienced a slightly higher probability of reoperation than the 1985 cohort for the first 3 years of follow-up. CONCLUSIONS: A rapid increase in surgery rates for spinal stenosis was identified over a 14-year period. The wide geographic variations and substantial complication rate from this elective surgical procedure (partly related to patient age) suggest a need for more information on the relative efficacy of surgical and nonsurgical treatments for this condition. The risks and benefits of particular surgical procedures for specific clinical and demographic subgroups as well as individual patient preferences regarding surgical risks and possible outcomes should also be evaluated further. These issues are likely to become increasingly important with the aging of the US population.

Aged↗
PubMed1996

Unusual presentation of late regional cardiac tamponade after aortic surgery.

Localized pericardial effusion leading to cardiac tamponade is seen occasionally in patients after cardiac surgery. This condition may be difficult to diagnose clinically because of unusual presenting symptoms and absence of conventional signs of cardiac tamponade. A case of localized pericardial effusion with presenting symptoms of fever and increasing fatigue is described in this study. The definitive diagnosis was made using transesophageal echocardiography. Surgical drainage of localized effusion resulted in prompt hemodynamic and symptomatic improvement.

Aortic Dissection↗
PubMed1995

Phonational profiles of male trained singers and nonsingers.

The purpose of this study was to compare the mean speaking fundamental frequency (SFF), speaking frequency range, and mean speaking intensity for a group of trained male singers and a group of age-matched non-singers in three age ranges: 20 to 35 years old; 40 to 55 years old; and older than 65 years. Each subject was recorded as he read "The Rainbow Passage" and produced the vowel /a/ to the limits of his phonational frequency range. The data indicated that the mean SFF of the nonsingers was significantly lower among the middle-aged speakers than with the young or elderly. In contrast, the tenors exhibited no age-related SFF trends, and the young bass/baritones exhibited lower SFF levels than the middle-aged or elderly. The elderly nonsingers produced frequency ranges that were smaller than any other group. Finally, the young nonsingers used greater speech intensity than did the other groups.

Adult↗
PubMed1994

The integration of voice science, voice pathology, medicine, public speaking, acting, and singing.

The integration of voice science, voice pathology, medicine, public speaking, acting, and singing has been central to evolution in all fields. The Voice Foundation Symposia have played a seminal and central role in fostering integration among disciplines. The result has been an improvement in the knowledge and practice in each field. And the future promises to be even more informative and exciting.

Congresses as Topic↗
PubMed1993

Phonational profiles of female professional singers and nonsingers.

Measures of the SFF, vocal intensity, phonational range, and habitual pitch level are reported for 39 professional singer and 39 nonsinger females, who were divided into three age groups (young, middle, and old age), with the professionals further divided into sopranos and altos. Each read the "Rainbow Passage" and spoke extemporaneously, from which measures of the SFF and vocal intensity were calculated; phonational range and habitual pitch levels were also determined. No significant differences were noted between the reading and speaking tasks. The SFF and intensity levels were significantly higher for the professionals in comparison to the nonsingers, but only for certain age groups. Moreover, whereas the nonsinger SFF levels varied significantly as a function of age, those for the professional singers did not. Although trends occurred, no significant differences were found for the mean phonational range or habitual pitch levels when the professionals and nonsingers were compared.

Adult↗
PubMed1990

Trauma in the workplace. An overview.

To attenuate the incidence of occupational deaths and injuries, which occur at a rate of approximately 25 deaths and 10,000 injuries daily, occupational health nurses must focus on injury control for the entire population of workers. Knowledge of the mechanics of injury and populations at risk for various types and severities of injuries is essential to developing injury prevention programs and appropriately responding to emergent injuries. The lack of a comprehensive and reliable surveillance method has been described as a major obstacle in evaluating the occupational injury problem, as well as measuring progress toward achievement of the 1990 Objectives in Occupational Safety and Health. Variations in the estimates have been attributed to different methodologies used in collecting surveillance data, including diverse definitions, inclusion criteria, and data sources. Lost workdays due to injuries reported for 1983 cost an estimated $33.4 billion in direct and indirect costs. Mining, construction, agriculture, and transportation are the most hazardous industries in terms of both fatalities and injuries. Activities appropriate for the occupational health nurse in preventing injury include retrospective analysis of injury patterns and costs, proactive inspection of the workplace for high risk factors, preplacement screening of workers, ergonomic analysis of jobs, evaluation of the type and use of personal protective equipment, provision of safety training, and collaboration with other agents of the firm in evaluating and designing injury reduction strategies and disaster plans.

Accidents, Occupational↗
PubMed1985

Out-of-pocket health expenses for Medicaid and other poor and near-poor persons in 1980.

The Medicaid program (Title XIX of the Social Security Act) was designed to provide access to health services at little or no out-of-pocket expense to low-income persons who might otherwise not be able to afford them. Information was collected through household interviews in the National Medical Care Utilization and Expenditure Survey (NMCUES) on total out-of-pocket expenditures for health care by noninstitutionalized persons in the United States in 1980. This report presents data to assess the degree to which Medicaid enrollees incur out-of-pocket expenses. These levels of expenditures are compared to those experienced by other persons not eligible for Medicaid who are below or near the official poverty level. Data contained in this report were derived from the National Household Survey (HHS), a panel survey of 6,600 households representative of the civilian, noninstitutionalized U.S. population, which is only one of the three surveys that were conducted as part of NMCUES. The other two surveys are a State Medicaid Household Survey (SMHS) of Medicaid households in four States and the Administrative Records Survey (ARS), a survey of existing Medicare and Medicaid administrative records for sample households. Since data were derived only from HHS, the findings in this report are national (or regional) in scope and cannot be tied directly to differences in individual State Medicaid programs. The data on eligibility and expenditures are all self-reported and have not been verified by administrative records. One definite limitation of these data is the exclusion from the NMCUES sample of all institutionalized persons. As a result, out-of-pocket expenses for one particularly high-cost group are excluded, and total out-of-pocket expenditures for each health insurance coverage group are understated. Another potential limitation of this analysis is that, as with many surveys, limited data on key items (such as out-of-pocket expenses and income) were at times missing from respondent reports. These missing data were imputed according to standard statistical techniques (see Appendix III). A variety of findings is presented, including data on the effect of health insurance coverage, demographic characteristics, health status, and continuity of Medicaid enrollment on out-of-pocket expenses. Within insurance coverage categories, Medicaid-covered persons had the lowest out-of-pocket expenses. This was true even though they had the highest mean per capita charges for care. Among the demographic characteristics that were analyzed, age and race had the most impact on the level of out-of-pocket health expenses.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1975

Reactions of kidney cells with cytotoxic antisera: possible evidence of kidney-specific antigens.

HL-A typing of cadaver kidney cell suspension by fluorochromasia cytotoxicity was successful in 76 out of 124 cases. In the 44 cases with confirmed phenotypes, 24 had identical results for lymphocytes and kidney cells. Twenty kidney cells had HL-A antigens not detected on that donor's lymphocytes, most commonly HL-A7 and HL-A8. In eight of these 20 cases, the additional kidney antigens brought the total to more than two per segregant sereis, in disagreement with an earlier report from this laboratory. The discrepancy was traced to a change in the method of complement preparation. The complement was successfully deprived of the resulting non-specific cytotoxicity for kidney cells by absorption with human red blood cells. Prior to absorption, the complement had rendered kidney cells susceptible to the lytic effect of anti-A and B red cell antibodies. Using the absorbed complement, a patient who had hyperacutely rejected two cadaver kidneys provided sera with an antibody reacting with, and absorbed by, the kidney cells but not the lymphocytes of the donors.

Antigen-Antibody Reactions↗