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Biomedical subjects

M Hodgson

Publications and source records attributed to M Hodgson.

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

Field studies on the sick building syndrome.

Field studies of the sick building syndrome have generally used questionnaires developed to define symptoms present over weeks and months, such as those asking ". . . do you usually . . .?" Although such studies have implicated ventilation systems as a major contributor to indoor air quality complaints, no specific exposures have been identified. An alternative approach is based on the short-term quantification of symptoms and characterization of the indoor environment with direct-reading or short-term sampling techniques. This paper summarizes the development of such a method in two studies in problem buildings and its subsequent application in a study in nonproblem buildings. The method correctly identified the postulated cause in a first building and generated a hypothesis for intervention in the second. In the nonproblem buildings, the levels of complaints appear related to the levels of VOCs, lighting, hours spent at desks, and crowding. This approach has suggested that dose-response relationships do exist in the sick building syndrome. Weaknesses of this approach include an inability to adequately address microbial characterization of indoor environments and the social and organizational predictors of complaints that are recognized to be of importance.

Air Pollution, Indoor↗
PubMed1991

Obesity and hepatotoxins as risk factors for fatty liver disease.

Generally fatty liver disease (FLD) is attributed either to alcohol, diabetes mellitus, or obesity. To evaluate this commonly held clinical belief, a case-control study of FLD in Western Pennsylvania was conducted with 19 cases being identified over a two year period. Cases of FLD were significantly heavier and were significantly more likely than controls to have exposures to either agents with recognised animal hepatotoxicity (odds ratio [OR] 8, p = 0.018) or to agents with potential hepatotoxicity--that is, documented in humans, animals, or expected on the basis of structure activity relations (OR = 4.5; p = 0.18). By contrast, they had not consumed significantly more alcohol than the controls. A logistic regression model of this experience suggests that both exposure to hepatotoxins and obesity are independent risk factors for FLD, which have an additive rather than a multiplicative interaction. Based upon these data, an occupational exposure to either recognised or potential hepatotoxins should be considered as a cause of liver dysfunction in subjects with FLD, independent of obesity and a history of alcohol consumption.

Adult↗
PubMed1991

Costs of occupational injury and illness in Pennsylvania.

A variety of state and federal data sources are used to estimate two critical components of the annual economic costs of occupational injuries and illnesses in Pennsylvania: foregone earnings of affected workers and medical costs. Foregone earnings costs resulting from occupational injuries and illnesses are estimated at between $1.22 billion and $2.02 billion in 1988. A number of potential adjustments to these estimates widen the range considerably. Estimates of medical costs range from $740 million to $797 million. Combining these two estimates gives total estimated costs of $1.96 billion to $2.82 billion.

Accidents, Occupational↗
PubMed1991

Psychometric evaluation of divers performing a series of heliox non-saturation dives.

Psychometric performance of 12 divers was evaluated throughout a series of 60-72-m in-water heliox non-saturation ('bounce') dives using a repeated-measures, within-subject design. Assessments were made onboard a dive tender, using a portable computerized battery within 30 min of the diver leaving the water, 2 h later, and on rest days. No significant decrement in performance was demonstrated either post-dive or throughout the series. Ten controls showed no alteration in performance due to environmental factors such as ship motion. The consistency of the results confirmed the suitability of this system for monitoring cognitive function during a series of potentially hazardous dives.

Adult↗
PubMed1990

On the accuracy of models for predicting sound propagation in fitted rooms.

The objective of this article is to make a contribution to the evaluation of the accuracy and applicability of models for predicting the sound propagation in fitted rooms such as factories, classrooms, and offices. The models studied are 1:50 scale models; the method-of-image models of Jovicic, Lindqvist, Hodgson, Kurze, and of Lemire and Nicolas; the emprical formula of Friberg; and Ondet and Barbry's ray-tracing model. Sound propagation predictions by the analytic models are compared with the results of sound propagation measurements in a 1:50 scale model and in a warehouse, both containing various densities of approximately isotropically distributed, rectangular-parallelepipedic fittings. The results indicate that the models of Friberg and of Lemire and Nicolas are fundamentally incorrect. While more generally applicable versions exist, the versions of the models of Jovicic and Kurze studied here are found to be of limited applicability since they ignore vertical-wall reflections. The Hodgson and Lindqvist models appear to be accurate in certain limited cases. This preliminary study found the ray-tracing model of Ondet and Barbry to be the most accurate of all the cases studied. Furthermore, it has the necessary flexibility with respect to room geometry, surface-absorption distribution, and fitting distribution. It appears to be the model with the greatest applicability to fitted-room sound propagation prediction.

Acoustics↗
PubMed1989

Cerebral perfusion deficits in dysbaric illness.

Decompression sickness (DCS) is usually categorised as type I (mild; peripheral pain, non-neurological) or type II (serious; neurological). Type II is regarded as predominantly a spinal cord disease with infrequent cerebral involvement. Cerebral perfusion was studied by injection of 99Tcm-hexamethylpropyleneamine oxime and single photon emission tomography in 28 divers with confirmed incidents of DCS and cerebral arterial gas embolism (CAGE). Cerebral perfusion deficits were present in all 23 cases of type II DCS and in all 4 cases of CAGE. No deficits were present in the single case of type I DCS. Type II DCS should be recognised as a diffuse, multifocal, central nervous system disease.

Adolescent↗
PubMed1988

The role of computed tomography in the assessment of neurologic sequelae of decompression sickness.

Computed tomographic (CT) scans were performed on 47 patients who had received recompression treatment for decompression sickness. A retrospective review of the case notes disclosed that 24 of the 47 patients had symptoms that suggested cerebral involvement. None of the reported CT abnormalities could be correlated with the clinical manifestations at presentation. It was concluded that the CT scan is not a cost-effective investigative tool for the posttreatment evaluation of decompression sickness.

Brain↗
PubMed1988

Cacosmia and neurobehavioral dysfunction associated with occupational exposure to mixtures of organic solvents.

This study examined the interrelationships among occupational exposure to mixtures of organic solvents, neurobehavioral functioning, and complaints of cacosmia. The latter was defined as nausea, headaches, and subjective distress in individuals exposed to neutral environmental odors. The authors administered a battery of cognitive tests to men with and without a history of solvent exposure and found exposed workers to be impaired across a wide range of cognitive domains. Multiple regression analyses of exposed workers demonstrated a highly significant relationship between a history of cacosmia and performance decrements on measures of learning and memory.

Cognition Disorders↗
PubMed1988

Central nervous system decompression sickness: latency of 1070 human cases.

Many aspects of central nervous system (CNS) decompression sickness (DCS) are poorly understood, including the temporal pattern of its presentation and the pathogenic mechanisms involved in the development of the disease. Using case histories and clinical series published in the literature and retrieved from treatment center records, this study is an attempt to define the interval between surfacing from a hyperbaric exposure and the onset of symptoms of CNS DCS. The results of 1070 cases of human CNS DCS were included in the study. The results show that the disease generally occurs rapidly: over 50% became symptomatic within 10 min of returning to 1 ATA, and in only 15% of cases was the onset of symptoms delayed for more than 1 h. Cerebral DCS had a more rapid onset than spinal cord disease: 50% of cerebral cases became apparent within about 3 min and a similar proportion of spinal cord cases within about 9 min from surfacing. The influence of these results on the diagnosis and treatment of dysbaric illness, on the safety of certain diving practices, and on possible pathogenic mechanisms is discussed.

Central Nervous System Diseases↗
PubMed1985

Metoclopramide kinetics at high-dose infusion rates for prevention of cisplatin-induced emesis.

Eleven male subjects aged 24 to 58 yr received cisplatin, 90 to 120 mg/m2 iv, in combination with other cytostatic drugs such as doxorubicin HCl and bleomycin. To prevent emesis, two high-dose metoclopramide regimens were started 2 hr before cytostatic therapy. Regimen A (n = 7) consisted of a loading dose infusion of 1 mg/kg/hr over 2 hr, followed by a maintenance infusion of 0.5 mg/kg/hr over 24 hr (total dose was 14 mg/kg in each cytostatic cycle). Regimen B (n = 6) consisted of half the metoclopramide dose. The following kinetics were derived from the metoclopramide steady-state plasma levels and the t1/2 of the elimination phase 26 to 38 hr after dosing (median value and range are listed): Steady-state plasma concentration in group A and group B was 750 (480 to 1520) and 360 (300 to 480) ng/ml plasma. Drug clearance in group A and group B was 0.67 (0.3 to 1.0) and 0.70 (0.5 to 0.8) l/hr/kg. Volumes of drug distribution in group A and group B were 4.4 (1.9 to 6.5) and 4.3 (3.2 to 5.9) l/kg. Values for the t1/2 in the elimination phase in group A and group B were 4.7 (3.0 to 5.4) and 4.3 (3.7 to 5.1) hr. It appears that metoclopramide kinetics at high doses were dose linear, i.e., without evidence of cumulation. There were few side effects; vomiting was effectively suppressed by both regimens.

Adult↗
PubMed1984

Adverse reactions to long-term diuretic therapy for hypertension.

Diuretics are important drugs used in therapy for hypertension. Diuretics have a number of side effects, some of which have long-term consequences. In this study diuretics were used to treat individuals with mild hypertension. Patients receiving diuretics as sole therapy had an increased mortality due to an excess number of deaths from myocardial infarction or sudden death. In patients given alpha-methyldopa or propranolol as well as a diuretic drug, this effect was not observed. The increased mortality may be due to an increased susceptibility to arrhythmias in individuals receiving diuretics, and this was prevented by drugs that interfere with the effects of the sympathetic nervous system.

Adrenergic beta-Antagonists↗
PubMed1980

Failure of therapy to improve prognosis in elderly males with hypertension.

Male patients, born between 1900 and 1925, have been entered in a study to ascertain the effect of therapy on the lifespan of people with different levels of blood pressure. Patients were divided into three groups--those with diastolic blood pressure below 12.6 kPa (95 mmHg), those with diastolic blood pressure between 12.6 kPa and 14.5 kPa (95 mmHg and 109 mmHg), and those with diastolic blood pressure higher than 14.6 kPa (110 mmHg). Patients in the first group were not treated, and all patients in the last group were treated. Patients in the middle group were subdivided into four subgroups, one of which received no treatment. Those in the second subgroup were placed on a reduced salt intake diet; those in the third subgroup were given a thiazide diuretic followed by alpha-methyldopa; and patients in the fourth subgroup were given a beta-blocking drug followed by a thiazide diuretic. The mortality rates in all groups, except one, were similar, and similar to that predicted for a normal population. The patients who were treated with thiazide diuretic regimen had a higher mortality rate which was due to a greater number of fatal myocardial infarcts and sudden deaths. These occurred in the first 2 1/2 years of therapy, and the cause of this is unknown. In this study, therapy did not produce an improvement in the lifespan of elderly males with hypertension.

Aged↗