Biomedical subjects

G Lewis

Publications and source records attributed to G Lewis.

At least 217 records · Page 12Linked to original sources

PubMed1991

Conservative surgery for trauma to the pancreatic head: is it safe?

The results of conservative operative management (involving no pancreatic resection) for 13 patients presenting with trauma to the pancreatic head over a period of 10 years were reviewed. Seven patients with injury of the pancreatic head without duodenal or ductal involvement made an uneventful recovery after simple drainage. The average hospital stay was 6.7 days. The remaining six patients with either duodenal (four patients) and/or ductal involvement (five patients) developed 22 major complications. One of these patients died of multiple organ failure, and the rest had an average hospital stay of 43 days. Injury of the vena cava was noted in five patients, but was not significantly associated with additional morbidity or mortality. Although simple drainage of pancreatic head injuries is associated with a low mortality, there is an unacceptably high incidence of complications if either the duodenum or pancreatic duct is involved. The authors recommend that simple drainage be restricted to patients in whom neither of these structures is injured.

Adult↗

PubMed1991

Parotid duct injury: is immediate surgical repair necessary?

This prospective study investigated the outcome for non-operative management of parotid duct injuries in 19 patients with injury confirmed by the methylene blue method. Nine (47 per cent) healed without complications. Short-term salivary fistulas complicated seven (36.8 per cent) wounds and a sialocele occurred in four (21.1 per cent). All complications resolved without the need for operative intervention. Acute surgical repair of damaged ducts can no longer be recommended, since conservative management of parotid duct trauma is both safe and effective; simple surgical procedures exist for the management of the rare long-term disorders.

Adult↗

PubMed1991

Should emergency room thoracotomy be reserved for cases of cardiac tamponade?

Forty-five trauma cases underwent emergency room thoracotomy (ERT) for circulatory collapse or cardiac arrest in the resuscitation area. There were no survivors in the blunt injury group (13 cases). In the penetrating group (32 cases) the overall survival was 25 per cent, with seven out of eight survivors having cardiac tamponade. Although ERT gives good results only for cardiac tamponade, not all cases of tamponade are clinically obvious on admission. The authors recommend that ERT be done on all cases of collapse or arrest following penetrating chest injury where signs of life have been present within the previous 3 min.

Cardiac Tamponade↗

PubMed1991

Factors affecting survival in Alzheimer's disease.

Factors affecting survival of 178 patients diagnosed using NINCDS/ADRDA criteria for Alzheimer's disease were studied. All patients were drawn from the Camberwell Health Authority Area and so were a representative sample of subjects from a clinical old age psychiatry service. The mortality rate of the sample was 3.5 times that expected after adjustment for age. Younger subjects had a higher standardized mortality ratio than older subjects. The cumulative three-year mortality of the sample was 47%. Factors shown to be associated with a reduced survival included: increasing age, longer duration of illness, male sex, presence of physical illness, poor cognitive function, observed depression and absence of misidentification syndromes. Apraxia was a stronger predictor of early death than aphasia or dysmnesia.

Aged↗

PubMed1991

Measurement of regional cerebrovascular haemoglobin oxygen saturation in cats using optical spectroscopy.

We describe the use of optical spectroscopy in the near infra-red light range to non-invasively measure regional cerebral haemoglobin oxygen saturation (rSHbO2) in cats during progressive cerebral hypoxia. This technique differs from spectroscopic techniques previously described in that the concentration ratio--percentage haemoglobin: oxygen saturation--is quantified. This saturation is the weighted summation of saturation in the cerebrovascular system: arterial, venous, and capillary beds. In a cat model of progressive cerebral hypoxia, a positive linear correlation between this regional measurement of cerebral saturation and actual saturation, calculated from cerebral arterial and mixed venous blood, was noted (n = 20, r = 0.88, p less than 0.01). The spectroscopic measurement rSHbO2 is also used to index cerebral oxygen extraction. During hypoxia spectroscopic indexed oxygen extraction (iOE) and cerebral arterial-venous difference in oxygen content were simultaneously measured. A least-squares positive linear correlation between these two parameters was noted [AVDO2 = iOE (0.05) + 4.4] (n = 40, r = 0.6, s = 1.2). Objective measurement of 'regional cerebrovascular haemoglobin saturation' and an index of cerebral oxygen extraction are possible using optical spectroscopy.

Algorithms↗

PubMed1991

Noninvasive cerebral optical spectroscopy for monitoring cerebral oxygen delivery and hemodynamics.

OBJECTIVE: To present an algorithm for noninvasive measurement of cerebral oxygen saturation (cerebral oximetry) and cerebral hemodynamics with near infrared spectroscopy. DESIGN: In vitro correlation of oximetry measurements with reference measurements; illustrative cases of hemodynamic and oximetric recordings. SETTING: Tertiary care neuroscience ICU. PATIENTS: Brain-injured patients with a prolonged, decreased level of consciousness chosen as illustrative examples. INTERVENTIONS: Two-channel multiple wavelength diffuse infrared transmission spectroscopy was interfaced with the scalp using adhesive. Transmission data were collected with gross superficial-to-deep spatial resolution. Saturation calculation based on the deep signal was observed longitudinally in the patient. With the same technology, arterial input and cerebral response functions, generated by iv tracer bolus, were deconvoluted to measure mean cerebral transit time. MEASUREMENTS AND MAIN RESULTS: A positive linear regression fit between diffuse transmission oximetry and measured blood oxygen saturation over the range 23% to 99% (r2 = .98, p less than .001) was noted. CONCLUSIONS: The approach used overcomes previously identified difficulties with cerebral oximetry, and demonstrates excellent in vitro correlation. The technique can be performed clinically without difficulty. A simultaneous measure of mean cortical transit time is possible.

Brain↗

PubMed1991

Cerebral oxygen metabolism measured during hypothermic circulatory arrest: a case report.

Infrared transmission spectroscopy was used to detect changes in cerebral oxy- and deoxyhemoglobin attenuation of infrared light in a patient undergoing circulatory arrest at 15 degrees C. Wavelength specific attenuation was used to determine hemoglobin oxygen saturation in the cerebral vasculature using a previously described paradigm. The fate of the residual oxygenated hemoglobin in the cerebrovascular compartment was followed during 15 min of circulatory arrest at 15 degrees C, and cerebral oxygen metabolism was identified as the progressive desaturation of this hemoglobin. The aggregate arterial and venous saturation fell from a normal value of 70% to an abnormally low value of 50%. Reperfusion resulted in near normalization of cerebrovascular oxygen saturation over 5 min, but evidence of persistent mild desaturation below prearrest baseline followed reperfusion. This case demonstrates both continued cerebral oxygen metabolism under hypothermic, circulatory arrest conditions and a cerebral oxygen delivery-consumption mismatch during reperfusion.

Journal Article↗

PubMed1991

Racism and psychiatry.

Explore the source record for details and available documents.

Attitude of Health Personnel↗

PubMed1991

Nocturnal elevation of glucose levels during fasting in noninsulin-dependent diabetes.

To define the spontaneous diurnal variations in glucose regulation during fasting in noninsulin-dependent diabetes (NIDDM), we measured circulating levels of glucose, insulin, C-peptide, GH, cortisol, and glucagon at 15-min intervals in 11 patients with untreated diabetes and 7 matched control subjects studied during a 24-h period. The rates of insulin secretion were derived from the concentrations of C-peptide by deconvolution using a two-compartment mathematical model for C-peptide distribution and metabolism. In both groups of subjects, despite continued fasting, glucose levels stopped declining in the evening and subsequently rose throughout the night to reach a morning maximum. Elevated levels persisted until noon. The morning glucose maximum corresponded to a relative increase of 23.8 +/- 5.5% above the evening nadir in NIDDM patients and 13.2 +/- 4.6% in nondiabetic subjects (P less than 0.05). In NIDDM patients, insulin levels and insulin secretion rates did not parallel the nocturnal glucose changes. In contrast, in control subjects, this nocturnal glucose rise coincided with a similar increase in insulin secretion rates. Cortisol concentrations in patients with NIDDM were higher than those in control subjects throughout the study period (P less than 0.001) and rose earlier in the evening than in control subjects, thus failing to demonstrate the normal nocturnal suppression. In both groups of subjects, the nighttime glucose elevation was temporally and quantitatively correlated with the circadian cortisol rise. GH secretion was increased in the evening and nighttime periods compared to the daytime values, and in NIDDM patients, but not in control subjects, the size of the morning glucose elevation was directly related to the magnitude of this increase in GH secretion (r = 0.88; P less than 0.01). Glucagon concentrations were similar in both groups of subjects and remained essentially constant throughout the study period. We hypothesize that the nocturnal glucose rise that occurs during fasting represents a normal diurnal variation in the set-point of glucose regulation amplified by counterregulatory mechanisms activated by the fasting condition.

Adult↗

PubMed1991

A randomised, double-blind, placebo-controlled trial of gemeprost (Cervagem) pessaries for cervical dilatation in non-pregnant women.

In a randomised, double-blind trial, 75 women received either placebo or a 1-mg gemeprost (Cervagem) pessary for cervical dilatation prior to gynecological procedures which require mechanical dilatation of the cervix. No significant difference was seen between gemeprost and placebo with respect to preoperative cervical dilatation. The incidence of vaginal bleeding and adverse effects was similar in each group.

Alprostadil↗

PubMed1991

Characterization of the performance of shoe insert materials.

It has been widely reported that shoe inserts are an effective interventional modality either for the relief of discomfort to the feet associated with a variety of orthopedic disorders or conditions or simply for comfort. Results from many types of experimental tests have been used to obtain the shock absorption capacity of shoe insert materials. The authors contend in this study that, while shock absorption is a highly desirable property, it is by no means the only that should be used to characterize these materials. Thus, a new index of performance of these materials is proposed. This index is computed from data, obtained in a simple experimental test, on both the shock absorption and energy return performances of the insert material.

Data Collection↗

PubMed1991

AIDS programmes in transition.

National AIDS programmes of industrialized countries are moving from rapid growth to consolidation. This transition should afford opportunities for strengthening the approaches to AIDS prevention.

Acquired Immunodeficiency Syndrome↗

PubMed1990

Lack of effect of high-dose biosynthetic human C-peptide on pancreatic hormone release in normal subjects.

We studied the effect of high doses of biosynthetic human C-peptide on pancreatic hormone secretion in response to oral (75 g) and intravenous [( IV] 0.33 g/kg of D50%) glucose on normal volunteers. The infusion of human C-peptide at a rate of 360 ng/kg/min body weight, increased the plasma C-peptide concentration from a basal level of 0.32 +/- 0.04 pmol/mL to 38.5 +/- 1.8 pmol/ml. Overall, C-peptide had no significant effect on the serum levels of glucose, insulin, proinsulin, glucagon, and pancreatic polypeptide, either under basal conditions or following IV and oral glucose administration. However, small decreases in glucose and insulin concentrations that were not statistically significant were seen during the first hour after C-peptide infusion. The results of the present studies are therefore consistent with the conclusion that even supraphysiologic plasma concentrations of infused C-peptide do not affect basal insulin secretion or overall insulin secretory responses to oral or IV glucose. However, we cannot definitively exclude a small reduction in insulin secretion in the first hour after oral glucose ingestion.

Adult↗

PubMed1990

Hydrophobic characterisation of Helicobacter (Campylobacter) pylori.

Cell-surface hydrophobicity of Helicobacter (formerly Campylobacter) pylori was tested by aqueous two-phase partitioning and hydrophobic interaction chromatography. The hydrophobicity of H. pylori greatly exceeded that of Campylobacter fetus subsp. fetus, C. jejuni and Bacillus subtilis. A partition coefficient (PC) of hydrophobicity in the two-phase system was determined for H. pylori. PC was dependent on pH and the PC value was increased by greater than 20-fold at pH 2.5. Lithium cations increased PC, indicating a net negative surface charge. The presence of urea prevented the relative loss of hydrophobicity at raised pH. Exposure of H. pylori to proteolytic enzymes reduced the ability of the bacteria to adhere to human polymorphonuclear neutrophils (PMN). These findings suggest that H. pylori possesses protein-associated hydrophobic factors that are responsible for the non-opsonic adherence to PMN cell membranes.

Bacterial Adhesion↗

PubMed1990

The case-control study in psychiatry.

Case-control studies involve 'cases' being compared to 'controls' with respect to 'exposures', possible aetiological (or associated) factors. Associations between a disease and an exposure can be explained by chance, reverse causality, confounding and biases or, lastly, by causality. However, confounders as well as information and selection biases can be adjusted for at the design (or analysis) stage of the study. The strength of an association can be measured by means of relative risk, calculated indirectly using the odds ratio. Well conducted control studies should produce accurate estimates of relative risks in many psychiatric investigations.

Adult↗

PubMed1990

Are British psychiatrists racist?

Out of a sample of 220 British psychiatrists, 139 completed a questionnaire regarding a case vignette of psychotic illness. The sex and 'race' of the vignette were varied and the responses compared. The Afro-Caribbean case was regarded as that of an illness of shorter duration, and requiring less neuroleptics than the white case. Respondents judged the Afro-Caribbean case as potentially more violent and thought criminal proceedings were more appropriate. The female vignette was perceived as less violent, less criminal, and less likely to need neuroleptics. Cannabis psychosis and acute reactive psychosis tended to be diagnosed more often and schizophrenia less often in Afro-Caribbean cases, refuting the claim that psychiatrists tend to overdiagnose schizophrenia in this group. Such 'race thinking' (a form of stereotyping which is distinct from ideological racism) could lead to inappropriate management.

Adult↗

PubMed1990

Comparison of the General Health Questionnaire and the Hospital Anxiety and Depression Scale.

The specificity and sensitivity of the HAD, 12-item GHQ and CIS were calculated by comparing the scores of dermatological patients on these tests with a criterion measure of disorder. Since psychiatry, along with many other branches of medicine, does not have an error-free criterion, it was assumed that the criterion was an underlying latent construct which was measured by all of the tests and could be derived by factor analysis from the scores on them. No differences were found between the two questionnaires (HAD and GHQ) in their ability to detect cases of minor psychiatric disorder although they were somewhat less reliable than the CIS.

Anxiety Disorders↗

PubMed1990

Discrimination on the grounds of diagnosis.

The study used the methodology of randomly allocating case vignettes to a sample of British consultant psychiatrists to assess the influence of a past diagnosis of alcohol dependence on present treatment attitudes. The case vignettes either did or did not include the previous diagnosis of alcohol dependence and the sex of the 'case' was also randomized. Psychiatrists receiving the vignette with the diagnosis of alcohol dependence were more likely to rate the patient as difficult, annoying, less in need of admission, uncomplaint, having a poor prognosis and more likely to be discharged from follow-up. There was minimal sex difference. Psychiatrist with a special interest in addictions regarded people with a past diagnosis of alcohol dependence as less difficult to manage than their non-specialist colleagues. The implications for education and treatment are discussed.

Adult↗