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Biomedical subjects

R Lane

Publications and source records attributed to R Lane.

At least 19 recordsLinked to original sources
PubMed1991

A microcomputer-controlled system for use in auditory physiology.

This report describes a digitally controlled system for use in auditory physiology in which signal generation and data acquisition are under the control of a single microcomputer. The system is designed to generate the complex waveforms required in neuroethological studies, and is able to generate these signals at frequencies of up to 160 kHz with a resolution of 1 Hz. The system is built around a commercially available digital hardware system, and augmented with custom components to enhance operation speed, precision and flexibility.

Hearing↗
PubMed1991

Basic techniques in pet avian clinical pathology.

An understanding of clinical pathology is extremely important for the pet avian clinician. The basics are often poorly understood by the busy practitioner. This article has served as a review for clinicians wanting the basics but having neither the time nor the resources to examine large volumes of material. This information has been designed to enable the veterinarian to understand better the limitations of the tests and the difficulties encountered by the avian technician in performing the tests so important in clinical avian practice.

Animals↗
PubMed1990

The effects of hypoxia and hypercapnia on perceived breathlessness during exercise in humans.

1. The sensation of breathlessness increases when ventilation is reflexly stimulated but it is not clear whether different stimuli have specific effects in the genesis of this sensation. 2. Our aim was to compare subjective assessments of the intensity of breathlessness at the same levels of ventilation induced by different combinations of reflex ventilatory stimuli. 3. Against a background of progressive exercise (maximum workload 170 W) in 'blinded' normal naive subjects, normoxic hypercapnia (maximum end-tidal CO2, PET, CO2, 56 mmHg) or isocapnic hypoxia (minimum O2 saturation 88%) was induced to achieve levels of ventilation (maximum 60 l min-1) 'matched' with those resulting from a higher intensity of exercise alone. Subjective breathlessness was rated with a visual analogue scale. 4. For a given ventilation, compared with exercise alone, breathlessness scores were similar during hypercapnia and were lower during hypoxia. 5. These results do not support the idea that during exercise, hypercapnia or hypoxia has a specific role in the genesis of the sensation of breathlessness. 6. The findings are consistent with the hypothesis that the degree of reflex ventilatory activation, however achieved, is an important determinant of the intensity of perceived breathlessness in healthy humans.

Adult↗
PubMed1988

A bizarre case of vehicular suicide.

The upper torso of a man was discovered under a highway sign next to tire tread marks leading from the highway and continuing beyond the sign. The victim's lower torso and automobile were also found along the same path 31 m (101 ft) and 41 m (133 ft) beyond the sign, respectively. The decedent was initially thought to be a disposed, homicide victim who had been dismembered by his assailant(s). Accident reconstruction revealed that the victim was the driver of the automobile and was transected by the highway sign stanchion as he protruded through the passenger side window of his moving vehicle. Based on the scene findings, autopsy, and psychological autopsy, the manner of death was classified as suicidal. The criteria used by medical examiners for vehicular suicide are also discussed.

Adult↗
PubMed1988

gamma-Aminobutyric acid release from synaptosomes prepared from rats treated with isonicotinic acid hydrazide and gabaculine.

The potassium-stimulated release of gamma-aminobutyric acid (GABA) from synaptosomes was determined in preparations from control rats and from rats treated with a convulsant agent [isonicotinic acid hydrazide (INH)] and an anticonvulsant agent (gabaculine). INH treatment brought about a significant decrease in Ca2+-dependent release of GABA with no effect on Ca2+-independent release, whereas gabaculine caused an increase in Ca2+-independent release with no effect on Ca2+-dependent release of GABA. Thus, the anticonvulsant action of gabaculine was not a simple reversal of the effects of INH on GABA release. The results indicate that there are at least two pools of GABA in nerve endings and support the hypothesis that exogenous GABA is taken up first into a pool that supplies GABA for Ca2+-independent release and then is transferred to a second pool (Ca2+-dependent releasable), where it mixes with newly synthesized GABA.

Animals↗
PubMed1988

Abolition of methacholine induced bronchoconstriction by the hyperventilation of exercise or volition.

Total pulmonary resistance was measured from continuous records of flow and oesophageal pressure in five normal subjects on three separate days before and after inhalation of methacholine. The dose of methacholine produced, on average, a fivefold increase in airway resistance. Immediately after methacholine inhalation the subjects underwent a progressive exercise test on a cycle ergometer (day 1) or voluntary hyperventilation (day 2) or remained resting (day 3). On the first day during exercise pulmonary resistance fell rapidly to baseline levels within two to three minutes and remained there for the 10 minute duration of the exercise. On day 2 voluntary reproduction of the same level and pattern of ventilation as during exercise resulted in a similar fall of resistance. On the third day, when the subjects remained at rest, pulmonary resistance remained raised for 10 minutes. It is concluded that the bronchodilator effects of exercise can be explained by the increased ventilation rather than the exercise itself, but with much smaller tidal volumes than have previously been thought necessary to reduce drug induced bronchoconstriction.

Adult↗
PubMed1988

Internal maxillary artery ligation for epistaxis: an analysis of failures.

The records of 100 consecutive patients undergoing transantral ligation of the internal maxillary artery (IMA) for epistaxis, including 15 patients who developed postoperative bleeding, were reviewed. Preoperative parameters predictive of surgical failure were advanced age, anemia, and a history of hypertension. The causes of postoperative epistaxis, as determined by surgical reexploration or angiography in 12 cases, included failure to identify the IMA in the pterygomaxillary space (6 cases), blood flow through partially closed clips on the IMA (2 cases), bleeding from posterior ethmoid arteries (2 cases), and revascularization of the nasal blood supply (2 cases). The incidence of surgical failure may be reduced by proper techniques of IMA identification and ligation.

Epistaxis↗
PubMed1987

Arterial oxygen saturation and breathlessness in patients with chronic obstructive airways disease.

Nine patients with chronic obstructive airways disease performed a 6 min self-paced walk (breathing air) on a treadmill and then identical (but operator-controlled) treadmill walks breathing either air or supplemental oxygen sufficient to just prevent arterial oxygen desaturation during the exercise. During the exercises, ventilation was recorded and patients recorded their sensation of breathlessness on a visual analogue scale (VAS) every 30 s. Breathing supplemental oxygen produced a small fall in mean exercise ventilation and a large and consistent reduction in mean exercise breathlessness. In seven patients the VAS scores were higher on air than with supplemental oxygen, at similar levels of ventilation. An analysis of covariance, to control for reduction in ventilation, showed a decrease in mean breathlessness when breathing supplemental oxygen, significant at the 8% level. The reduction in breathlessness produced by preventing exercise desaturation cannot be explained by the decrease in ventilation. This suggests that hypoxia may be a stimulus for breathlessness. The mechanism is unknown.

Aged↗
PubMed1987

Breathlessness and respiratory mechanics during reflex or voluntary hyperventilation in patients with chronic airflow limitation.

1. Six patients with chronic airflow limitation rebreathed CO2. Subsequently they voluntarily copied their stimulated breathing pattern while normocapnia was maintained. On a separate occasion four of these patients performed progressively increasing exercise and later copied these breathing patterns. 2. During all experiments flow, ventilation and pleural pressures were recorded. In addition, breathlessness was measured on a visual analogue scale every 30 s. 3. In these patients voluntary copying of either form of stimulated breathing resulted in diminished breathlessness and in some cases in complete abolition of the sensation, despite similar levels and patterns of ventilation in the two situations. 4. No systematic or consistent differences in the mechanics of breathing between stimulated and voluntarily copied breathing were found. 5. There was no correlation found between breathlessness score and any mechanical variable measured. 6. These results show that despite similarity in mechanics between stimulated and voluntary hyperventilation, the sensation of breathlessness is much diminished during the latter in these patients. This suggests that the sensation of breathlessness is more dependent upon the awareness of central processing than upon input from peripheral mechanoreceptors.

Aged↗
PubMed1987

Abdominal aortic aneurysms and coronary artery disease: is a more aggressive approach indicated?

A retrospective study was undertaken to assess the influence of known ischaemic heart disease on the operative and the long-term survival of patients undergoing elective repair of an abdominal aortic aneurysm. One hundred and seventy-one patients underwent elective surgery between June 1977 and December 1983. The patients were divided on routine clinical grounds into cardiac and noncardiac groups. Ninety-five patients had a history of heart disease and/or an abnormal resting pre-operative ECG. Seventy-six patients had no history of heart disease and a normal pre-operative resting ECG. Two of the seven operative deaths were due to myocardial infarction with one each from the cardiac and noncardiac groups. Eight patients suffered an acute myocardial infarction with five from the cardiac and three from the noncardiac group and this was not significantly different. The overall survival of 95% at 1 year and 76% at 5 years closely follows the age/sex matched Australian population. The survival at 1 year in the cardiac group was 97% and 95% in the noncardiac group. The 5 year survival was 72% and 79% respectively. During follow-up to December 1984, 11 patients died from ischaemic heart disease with six from the cardiac and five from the noncardiac group. No significant difference was found between the two groups in the incidence of myocardial infarction or the short- and long-term survival. This study does not support a more aggressive approach to coronary artery disease in the pre-operative management of patients with abdominal aortic aneurysm.

Aged↗
PubMed1987

Gabapentin as an antiepileptic drug in man.

Gabapentin, 1-(aminomethyl) cyclohexane acetic acid, is a GABA analogue whose antiepileptic properties were tested in a double blind cross-over trial design as add-on therapy in a dose ranging study which compared 300 mg, 600 mg, and 900 mg/day (each dose given for 2 months) in 25 patients with severe partial and generalised epilepsies. A dose related antiepileptic effect was observed. All three doses were well tolerated and no psychometric impairment was noted. No significant drug interactions were seen. The drug appears worthy of further assessment.

Acetates↗
PubMed1978

Air quality correlates of chronic disease mortality: Harris County, Texas 1969--1971.

Air quality correlates of chronic disease mortality in 180 census tracts of Harris County, Texas, were studied using 3 years mortality for 1969--1971. This study was designed to test with a different data base the universality of several study results which have reported significant correlations between heart disease and air pollutants. Air quality data (suspended particulates, benzene solubles, sulfur dioxide, and metals associated with particulates: copper, mercury, manganese, lead, nickel, zinc, chromium, and cadmium) were related to both sex and age adjusted crude death rates, and cause-specific death rates for age cohorts for 7 categories of heart disease, and pneumonia, asthma, cancer, tuberculosis, and accident deaths. The results of the study were in agreement with the findings of the other researchers who used national data. Suspended particulates and cadmium concentrations were found to be correlated (r=.38, .36; P less than .001) with ischemic heart disease (IHD). Many other significant correlations are reported but are not cause-specific. Socio-economic indicators were also correlated with IHD, thus confounding the issue. Further work is planned using more sophisticated statistical techniques to disentangle the relative contribution of each of these highly intercorrelated factors. No causality can be assigned at this stage, although this study, with the other cited, points to possible risk factors for IHD which need further evaluation.

Adult↗
PubMed1977

Meteorologic factors and temporal variations of cardiac mortality in an urban setting in a desert climatic zone.

The aim of this investigation was to study, by use of the unbiased and rigorous techniques of lagged cross-covariance and spectral analyses, the associations between daily cardiac mortality and weather conditions in Beersheba, an urban center situated in a hot and dry climatic zone. The results of the analyses point to the existence of seasonal differences in mortality, with a peak in winter. Of greater interest is the statistical documentation of temporal associations between short-term increases in daily mortality and certain weather situations corresponding to the transitional periods of turbulent atmosphere with below normal air temperatures, strong gusty winds and a drop in relative humidity, i.e., conditions accompanying the intrusion of a winter cold wave. The crests in short-term mortality occurred most often within a week of the intrusion of the cold air masses. No consistent cross association was found between high summer temperatures and mortality. The results of this investigation are discussed in the light of those previously reported for Tel Aviv (a coastal city) and Jerusalem (a city situated at a high altitude).

Atmospheric Pressure↗