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Biomedical subjects

C Patel

Publications and source records attributed to C Patel.

At least 73 records · Page 4Linked to original sources

Pharmacology of propranolol in patients with cirrhosis and portal hypertension.

Ten patients with cirrhosis and protal hypertension received an initial 20 mg oral test dose of propranolol and subsequently 160 mg of a slow release preparation, orally, each day for seven days. Protein binding, serial plasma propranolol concentrations and effects on heart rate were studied. Protein binding was slightly reduced (mean 85%, range 78.9-88.1%) compared with four normals (mean 87.9%). In patients with severe liver disease (serum albumin less than 30 g/l) propranolol remained detectable in plasma 24 hours after the single 20 mg dose and high steady state concentrations (mean 266.5 ng/ml, range 84-406) were observed during regular dosing. At steady state there was a significant correlation between log total plasma propranolol concentrations and the percentage fall in heart rate (r = 0.659, p less than 0.05). We suggest that in patients with severe liver chronic disease (serum albumin less than 30 g/l), propranolol therapy should be initiated in hospital. The starting dose should be low (20 mg of the conventional formulation tds or 80 mg of the slow release preparation daily) and that regular monitoring of the heart rate should be carried out.

Aged↗

The value of screening for autoantibodies in patients with non-specific symptoms.

An autoantibody screen is often requested in patients with non-specific symptoms such as pyrexia of unknown origin. However, in a survey of 100 consecutive requests for this investigation in such patients only one patient was encountered in whom the investigation led to a positive diagnosis at an estimated cost of pound 2500. These requests accounted for 5% of the total workload. These observations reaffirm that this should remain a second line investigation and should be deferred until more likely diagnoses have been excluded.

Adolescent↗

Infectious endocarditis caused by Actinobacillus actinomycetemcomitans.

Actinobacillus actinomycetemcomitans is a very uncommon cause of infectious endocarditis. The organism was first described in 1912. Thjotta and Sydnes reported its isolation in pure culture from a long standing abscess which had developed after tooth extraction. Subsequently this organism was found to be part of the normal flora, and the organism was defined as a slow growing, fastidious gram negative bacillus. Carbon dioxide is essential for the growth of A. actinomycetemcomitans. Approximately 50 cases of endocarditis due to A. actinomycetemcomitans have been reported since the first case reported in 1964. The purpose of this report is to document a case of endocarditis due to A. actinomycetemcomitans and to stress the value of the echocardiogram in the assessment of patients with endocarditis.

Actinobacillus↗

The Osborn wave in hypothermia.

A patient is reported who presented with fatal hypothermia. The electrocardiographic changes of a sinus bradycardia, prolonged QT interval and Osborn waves were documented and correlated with body temperature. The possible genesis of these electrocardiographic changes is reviewed in this article.

Bradycardia↗

Immunology of inflammatory bowel disease.

Although the aetiology of ulcerative colitis and Crohn's disease remain unknown, immunological effector mechanisms become activated within the inflamed mucosa and may be responsible for the pathogenesis of chronic disease. There is an increased production of immunoglobulin within the mucosa, some of which has specificity for bacterial antigens, and complement activation occurs during exacerbation of the disease. Lymphocytes isolated from peripheral blood, or from the intestinal mucosa, are cytotoxic to colonic epithelial cells in vitro; a reaction which can be modulated by serum factors and bacterial antigens. Within the mucosa, there are increased populations of T lymphocytes although there is no change in the ratio of helper- to suppressor-cells as defined by phenotype. Studies of immunoregulatory control have shown that there may be alterations in the modulation of the local immune response, especially during active disease, although it is not clear whether these changes are primary or merely secondary to inflammation. It is posulated that many of the humoral and cellular responses to gut-associated antigens occur as a result of increased antigen absorption, increased presentation of antigen to the immune system due to the expression of Class II antigens by the inflamed epithelium and altered immuno-regulatory control.

Antigen-Antibody Complex↗

Value of radionuclide angiogram for the diagnosis of Ebstein's anomaly.

A radionuclide angiogram in a patient with Ebstein's anomaly showed a very dilated right atrium with a minimally enlarged right ventricle and a normal sized left ventricle. This study led to the establishment of a definitive diagnosis by means of an echocardiogram. Late close of the tricuspid valve was demonstrated. In addition prolapse of the tricuspid and mitral valves was documented. A tricuspid valve prolapse has never been reported in this condition.

Blood Pressure↗

Upper gastrointestinal endoscopy in systemic vasculitis presenting as an acute abdomen.

Three cases of upper gastrointestinal vasculitis presenting as acute abdominal emergencies highlight an uncommon but often fatal presentation of systemic vasculitis. Although abdominal symptoms are common in such diseases, there may be a doubt during assessment of the patient as to whether the gastrointestinal tract is the prime target organ. Radiology is often negative during the acute illness. Endoscopy was important in documenting early and more advanced bleeding lesions of polyarteritis nodosa (PAN) and Henoch-Schoenlein disease, both conditions in which upper gastrointestinal lesions are rare. The gastric and duodenal vasculitic lesions demonstrated by endoscopy in such a clinical setting were confirmed histologically. Endoscopic assessment and early aggressive medical therapy contributed significantly towards the overall successful outcome. Gastroduodenoscopy has not been used either routinely or as an emergency investigation for the assessment of patients with vasculitis who present with acute abdominal pain. Involvement of the stomach and duodenum by vasculitis is therefore poorly appreciated, but remains a serious complication of vasculitic disease when the gastrointestinal tract is the prime target organ, and the information gained by endoscopy in a difficult clinical situation might alter the overall outcome of the disease.

Abdomen, Acute↗

Nucleoli, micronucleoli, and nucleolus-like structures in human oocytes at meiotic prophase I studied by the silver-NOR technique.

Meiotic nuclei preparations obtained from human fetal ovaries were studied with the silver-NOR technique. At leptotene, the NOR's were located at the periphery of the nucleoli. The mean number of NOR's per nucleus was 6.4. Moreover, 2-12 micronucleoli, each containing an Ag-positive zone, were observed. At pachytene, each nucleolus was divided into two zones, one of which was Ag-positive. The mean number of Ag-positive zones was 2.1 per nucleus. The subterminal region of the short arm of nucleolar bivalents was in contact with the argyrophilic nucleolar zone. In most cells, micronucleoli were dispersed between the bivalents. A single rounded body which stained heavily with silver was consistently observed. At early diplotene, the NOR's separated, appearing again as distinct rounded Ag-positive structures embedded in the peripheral part of the nucleoli. The silver-stained round body was still visible. Eight to twelve micronucleoli were observed. At a more advanced stage of diplotene, the number of micronucleoli increased, varying from 20 to 50 per nucleus. These observations suggest that the micronucleoli, already visible at the leptotene stage, are the morphological expression of an early transcription of amplified rDNA. The biological significance of the Ag-positive round body remains obscure, but the consistency of its appearance suggests that it has a specific function somehow related to nucleolar proteins.

Cell Nucleolus↗

Augmentation of flap survival by thymoxamine.

An experimental study in rats showed that the use of the alpha-receptor antagonist, thymoxamine could increase the blood supply to an ischaemic flap. Thymoxamine has a very short half-life, must be given frequently to be effective, but has the significant advantage that its action can be reversed by noradrenaline. When a flap is in trouble, alpha-receptor blockade by thymoxamine might help dramatically in its salvage.

Animals↗

Improved stability of methanolic Wright's stain solution with dual additives.

Degradation of methanolic Wright's stain solutions was greatly diminished with the addition of diethylamine hydrochloride and dimethylamine hydrochloride as costabilizers. Precipitation problems were eliminated by the dual additives. The stabilized stain solutions demonstrated good staining performance on blood smears. Methods for predicting the shelf life using calculated analytical parameters are described. Using these methods, the shelf life of a control stain solution was predicted to be 0.7 years; predicted shelf life was more than tripled with the addition of diethylamine hydrochloride and was increased approximately 27 times with the addition of both diethylamine hydrochloride and dimethylamine hydrochloride.

Blood Cells↗

Controlled trial of biofeedback-aided behavioural methods in reducing mild hypertension.

Employees of a large industry were screened for the presence of coronary risk factors. A total of 204 employees, aged 35-64 years, with two or more such factors (serum cholesterol concentration greater than or equal to 6.3 mmol/l (243.6 mg/100 ml), blood pressure greater than or equal to 140/90 mm Hg, and current cigarette consumption greater than or equal to 10 cigarettes a day) were randomly allocated to a biofeedback group receiving training in relaxation and management of stress or a control group. Both groups received simple health education literature. After eight weeks of training, and again eight months later, the biofeedback group showed a significantly greater fall in systolic and diastolic blood pressures than the control group (p less than 0.001). Plasma renin activity and plasma aldosterone concentration were measured in a subsample at entry to the study and again at eight weeks and eight months; both showed a greater reduction in the biofeedback compared with the control group at eight weeks' follow-up. The greater reduction in blood pressure in the subjects in the biofeedback group compared with the control group (11.0 mm Hg systolic and 8.8 mm Hg diastolic), persisting eight months after the training, suggests that relaxation-based behavioural methods might be offered as a first-time treatment to patients with mild hypertension.

Adult↗

Improved stability of methanolic wright's stain with additive reagents.

Additive reagents have been investigated to improve the stability of methanolic Wright's stain. The addition of ammonium halides, monoalkylamine hydrochlorides, dialkylamine hydrochlorides or trialkylamine hydrochlorides to methanolic Wright's stain was found to enhance the stability of stain components in methanol. No change in performance is observed with these additives present. Random precipitation in the stain solution was still observed with the addition of ammonium halides and monoalkylamine hydrochlorides. No precipitation was found in stain solutions containing hydrochlorides of most dialkylamines and trialkylamines. Of the compounds evaluated, 0.6% diethylamine hydrochloride added to methanolic stain solutions produced the most desirable overall results. Mechanisms of stabilization and precipitation in these stain solutions are proposed. Essentially, separation of the thiazine-eosinate ion pair through interaction with an appropriate additive increases stain stability. The solubilities of thiazine-eosinate or additive cation-eosinate ion pairs in methanol determine the formation of precipitate in such stain solutions.

Amines↗

Routine cytodiagnosis of pulmonary malignancies.

Anesthesiologists normally discard the material routinely suctioned from the tracheal tube of patients under general endotracheal anesthesia. We preserved, and later examined microscopically, specimens from 10,621 patients. We found 11 cytologically abnormal smears from subjects with unsuspected pulmonary involvement, an incidence slightly more than 1:1,000. The accuracy of our method was assessed by calculation of the percent of abnormal smears obtained from patients with prediagnosed bronchogenic carcinomas: 40% when suctioned material was immediately spread on slides, and 67% when cellular concentration was achieved by mucolysis followed by filtration or centrifugation. Secretions normally discarded can reveal much information that would otherwise be missed. Our method may be useful if applied to patients at risk (heavy smokers, workers with asbestos, nitrosamine, or benzopyrine, miners of radioactive material, etc) who undergo general anesthesia for incidental surgery.

Adolescent↗