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Biomedical subjects

R Lane

Publications and source records attributed to R Lane.

At least 91 records · Page 5Linked to original sources
PubMed1985

The measurement of breathlessness induced in normal subjects: validity of two scaling techniques.

The intensity of breathlessness induced by ventilatory stimulation resulting from hypercapnia, hypoxia or exercise has been quantified in normals by using the two different sensory scaling techniques of linear visual analogue scaling and ratio magnitude estimation. In naive individuals both techniques show good face validity. When related to ventilation, quantification of breathlessness is moderately reproducible with both methods, even when subjects are kept in ignorance of the pattern of ventilatory stimulation. There is a small within- and large between-subject variability with both scaling techniques; possible factors responsible are discussed. The reproducibility of visual analogue scaling when related to ventilation is independent of the nature of the ventilatory stimulus and is maintained over intervals as long as 1 week when memory for the score given is unlikely to be an important factor. The difficulties of interpreting subjective estimates of perceived breathlessness are discussed, together with the relative merits of the two scaling techniques.

Adult↗
PubMed1985

Breathlessness during different forms of ventilatory stimulation: a study of mechanisms in normal subjects and respiratory patients.

This study investigates the mechanisms underlying the perception of breathlessness induced by hypoxia and hypercapnia in both naive normal subjects and patients with respiratory mechanical problems. In normal subjects separately receiving both oscillating hypercapnic and hypoxic ventilatory stimulation, equivalent peak stimulus intensities in end-tidal gas were associated with a 'damped' ventilatory response when the frequency of stimulation was increased. A concomitant fall in peak breathlessness levels on a visual analogue scale was recorded in each case. In normal subjects and patients, the voluntary copying of a ventilatory pattern recorded during oscillating hypercapnic stimulation was associated with a marked diminution or complete absence of breathlessness despite equivalent levels of peak ventilations achieved. Voluntary copying of hypercapnic stimulated ventilation was not associated with any demonstrable change in the distribution of muscle movements between the chest wall and abdomen. These results suggest that the intensity of breathlessness depends on the level of effective reflex stimulation of the respiratory-related neurones in the medulla. They cannot be explained solely in terms of perception of afferent neural information arising from either chemoreceptors or respiratory mechanoreceptors.

Abdomen↗
PubMed1985

Fluid filled oculoplethysmography and carotid artery disease: imperfect but useful.

Fluid filled oculoplethysmography (OPG) is a widely used method of assessing carotid stenosis but it has limitations in the detection of bilateral internal carotid artery lesions and of external carotid artery stenoses. In this study, 157 consecutive patients having carotid angiography and fluid filled OPG were assessed to determine the accuracy of the technique and define the sources of error. Haemodynamically significant stenosis (HDS) was defined as at least 50% stenosis of the internal carotid artery (ICA). Only the most severely stenosed side of the 35 bilateral HDS lesions was detected owing to the poor reliability of ear pulse delays. Eye/eye delays alone detected the most severely stenosed side in 82 of 98 patients with an HDS stenosis of one or both ICAs for a sensitivity of 84% a specificity of 71% (41/59) and accuracy of 79% (81/157). The measurement of ear/ear pulse delays for external carotid artery (ECA) stenosis had a sensitivity of only 15% (5/34). Ear/eye pulse delays detected none of the 35 patients with bilateral HDS ICA stenosis. Bilateral equal HDS ICA stenoses were a significant source of error. Stenotic disease was present in the aortic arch and branches (five patients) or the carotid siphon (eight patients) and in seven cases it resulted in an incorrect localization on OPG. There was no diagnostic relationship between the severity of delay and the presence of total occlusion. Chronic local eye pathology was present in 13 patients and did not affect the results of the OPG. We have ceased to use ear pulse measurements for routine assessment but continue to use the eye/eye delays in conjunction with a carotid doppler imaging system.

Adult↗
PubMed1985

Intraoperative ultrasound during carotid artery surgery.

Intraoperative B-mode ultrasound (OPUS) has been used to scan 155 carotid bifurcations during endarterectomy. Intimal flaps, residual plaque and suture line stenosis were detected by this method. Most defects were found in the external carotid artery (11%) and the importance of adequately clearing this vessel is stressed. The internal carotid artery had defects in 8% of cases, most of which were of a minor nature (less than 30% encroachment on luminal diameter). The presence of minor technical defects at operation was not significantly associated with the development of postoperative bruits or restenosis. Major defects were corrected at the time of surgery. OPUS is a useful adjunct in ensuring a technically satisfactory endarterectomy.

Carotid Arteries↗
PubMed1985

Vein, Gore-tex or a composite graft for femoropopliteal bypass.

Experience with a variety of graft materials has suggested that the nature of the material significantly affects long term graft patency. In 126 femoropopliteal bypass grafts performed during a 54 month period, the over-all patency rate for RSV (68.0 per cent at three years) was significantly superior to either Gore-tex alone (34.1 per cent at three years) or a composite graft of RSV below the knee anastomosed to Gore-tex above the knee (49.3 per cent at three years). The composite graft performed significantly better than Gore-tex alone, however, in patients with poor runoff or when a distal anastomosis was performed below the knee. The reason for the superior performance of RSV or the composite over Gore-tex alone probably relates to compliance mismatch at the site of the distal anastomosis. While RSV remains the graft material of choice for femoropopliteal bypass grafting, a extensive role exists for the use of a composite graft rather than Gore-tex graft alone especially in patients with poor runoff with an anastomosis below the knee.

Aged↗
PubMed1984

Colour-coded carotid Doppler imaging: an angiographic comparison of 324 bifurcations.

The accuracy of a colour-coded Doppler ultrasound imaging system in the assessment of the extracranial carotid tree is presented. A series of 162 consecutive patients (324 bifurcations) were assessed with angiographic control. Doppler frequency shifts of between 3600 and 5000 Hz, corresponding to yellow on the colour code, detected carotid arteries that were stenosed greater than or equal to 50% with a sensitivity of 95%, a specificity of 72% and an overall accuracy of 81%. At frequency shifts of over 5000 Hz corresponding to the blue code, the sensitivity was 83%, specificity 90% and accuracy 87%. With highly stenosed lesions (90-99%), 24% were incorrectly diagnosed as occlusion by the imager. In those cases with a haemodynamically significant lesion on one side there is no evidence of a compensatory increase in velocity on the other side. The technique is readily learnt but an awareness of its pitfalls is essential for accurate scanning and these are discussed. Carotid Doppler imaging has superseded phono-angiography and peri-orbital Doppler examination in our laboratory and is used with the oculoplethysmograph in the routine assessment of patients with suspected carotid bifurcation disease.

Angiography↗
PubMed1982

A comparison of non-invasive methods in the assessment of extracranial carotid artery disease.

The accuracy of four-invasive methods used in the evaluation of the extracranial carotid arterial system are presented. Three of the methods were the flow dependent whilst the fourth was an ultrasonic imaging system. A consecutive series of 67 patients, (134 carotid arteries), having carotid angiography were investigated by means of carotid phonoangiography (CPA), oculoplethysmography (OPG), supra orbital Doppler (SOD) and B mode ultrasound scanning. The sensitivity of the B mode ultrasound was 81% with the OPG, CPA and Doppler method yielding sensitivities of 51%, 56% and 63% respectively. The specificity of both the OPG 95% and the Doppler 90% wqs high. The combined use of both B Mode ultrasound and OPG or Doppler will provide an improved overall accuracy in the assessment of extra cranial carotid stenosis.

Arterial Occlusive Diseases↗
PubMed1980

Regional adipose cellularity and reliability of adipose cell size determination.

Regional adipose cell size was assessed in 18 males ranging in age from 20 to 36 years. These measures were correlated to total body fat determined by hydrostatic weighing. Adipose samples were removed from the gluteal, abdominal, and subscapular regions using a needle aspiration technique. The tissue was incubated in collagenase to release individual cells that were immediately photographed under a microscope. To establish the reliability of adipose cell size assessment over time, fat biopsies were secured on 2 separate days. No significant difference was found for any region between day 1 and 2 adipose cell measures. Gluteal cell diameter (90.3 mu) was significantly larger than the abdominal (81.0 mu) and subscapular (78.6 mu) cell diameter (90.3 mu) was significantly larger than the abdominal (81.0 mu) and subscapular (78.6 mu) cell diameters. Total body fat correlated highest with gluteal cell size (r = 0.76) compared with the abdominal (r = 0.67) or subscapular (r = 0.70) regions. This study also examined the number of adipose cells required to subscapular (r = 0.70) regions. This study also examined the number of adipose cells required to obtain a reliable and representative mean value of adipose cell size. Using a sequential estimation analysis it was found that adipose cell diameters of the abdominal, gluteal, or subscapular regions can be reliably estimated with fewer than 100 cells.

Abdomen↗
PubMed1980

Adenocarcinoma of the ethmoid following radiotherapy for bilateral retinoblastoma.

Adenocarcinoma of the ethmoid sinus is rare, representing only 4-8% of malignancies of the paranasal sinuses. An extraordinary case of papillary adenocarcinoma of the ethmoid sinus arising 30 years following high-dose radiotherapy for bilateral retinoblastoma is presented. Retinoblastoma, though occurring only once in every 23,000 to 34,000 births, is the most common malignant intraocular tumor of childhood. Second fatal mesenchymal and epithelial primaries have been described in 8.5% of patients with bilateral retinoblastomas previously treated with radiotherapy; however, papillary adenocarcinoma arising within the paranasal sinuses has not been reported. Histologically, the findings of a papillary pattern of poorly differentiated, mucicarmine-staining cells enclosing gland-like spaces, and the absence of pseudorosettes, melanin, mesenchymal and peripheral neural elements supports an epithelial origin of this tumor. Agressive treatment including partial maxillectomy, radical pansinusectomy, radical neck dissection followed by regional radiotherapy and systemic chemotherapy failed to prevent the development of fatal hepatic metastases. The high incidence of second fatal primary neoplasms in patients with bilateral retinoblastomas receiving radiation suggests an innate susceptibility that may add to the risk of radiotherapy. Careful long-term head and neck surveillance is mandatory if early aggressive management of these extremely lethal tumors is to be successful.

Adenocarcinoma, Papillary↗
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↗