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Biomedical subjects

M R Lewin

Publications and source records attributed to M R Lewin.

84 records · Page 5Linked to original sources

Plasma gastrin and acid secretion in man following stimulation by food, meat extract, and insulin.

A radioimmunoassay for gastrin was set up and its sensitivity and specificity were studied. The assay was then used to investigate the plasma gastrin responses in man to a normal meal and to stimulation by insulin hypoglycaemia or by instilling meat extract into the stomach. The results showed that insulin and meat extract produced very similar plasma gastrin responses which were certainly not less than those produced by feeding. However, the acid secretory response to insulin was greater than that to meat extract. This indicated that the tests acted in different ways and both may be useful in the assessment of gastric secretion.

Animals↗

Plasma calcium fractions and the protein-binding of calcium in normal subjects and in patients with hypercalcaemia and hypocalcaemia.

A study is reported of the estimation of plasma calcium fractions and the calcium-binding affinity of plasma proteins in a total sample of 59 people, which included 29 normal subjects and 30 patients with either hypercalcaemia or hypocalcaemia. It was demonstrated that when the sample was considered as a whole there was a significant correlation between the total plasma calcium concentration and the ultrafiltrable, ionized, and protein-bound calcium fractions and between the ultrafiltrable and ionized fractions. We have also demonstrated that in patients with either hypercalcaemia or hypocalcaemia, including acidotic uraemics, the calcium-binding affinity of the plasma proteins did not differ significantly from that in normal subjects. A significant correlation was also found between the total plasma calcium concentration and the ultrafiltrable, ionized and protein-bound calcium fractions when the normal subjects and the groups of patients with hypercalcaemia and hypocalcaemia due to chronic renal failure were considered as separate groups. The group of patients with hypercalcaemia included patients both with hyperparathyroidism and with hypercalcaemia due to other causes.

Adolescent↗

Ultramicrofluorimetric determination of calcium in plasma.

A precise and reproducible method is described for the ultramicro fluorimetric determination of calcium in plasma, based upon the formation of a fluorescent complex between calcium and calcein at a strongly alkaline pH. In a group of normal subjects, the mean concentration of plasma calcium was 9.66 mg/100 ml with a normal range of 8.9 to 10.4 mg/100 ml.

Adolescent↗

The effects of cognitive-behavior therapy for panic disorder on comorbid conditions.

In a replication and extension of prior research (Brown, Antony, & Barlow, 1995) examining the impact of treatment on additional diagnoses, our study investigated the effects of cognitive-behavioral treatment for panic disorder on frequency and severity of comorbid conditions in 33 principal panic disorder patients. Patients were diagnosed using the Anxiety Disorders Interview Schedule-Revised (ADIS-R; Di Nardo & Barlow, 1988) and assigned severity ratings indicating degree of distress and/or impairment for both principal panic disorder and comorbid conditions. A high rate of comorbidity (63.6%) was found at pretreatment. Following cognitive-behavioral treatment, there was a significant reduction in the number of patients with at least one additional diagnosis (p < .01); the greatest declines were found in comorbid social phobia and generalized anxiety disorder. Severity ratings also declined significantly from pre- to posttreatment for comorbid social phobia, generalized anxiety disorder, and posttraumatic stress disorder (p < .01) and were marginally significant for depression. There was a trend for comorbidity to reduce likelihood of achieving high improvement in panic at posttreatment. Implications of these findings for classification and treatment mechanisms are discussed.

Adult↗

Multimodal comparisons of social phobia subtypes and avoidant personality disorder.

The purpose of the present study was to further clarify the behavioral, physiological, and verbal response of patients with circumscribed social (speech) phobia, generalized social phobia without avoidant personality disorder, and generalized social phobia with avoidant personality disorder. Patients completed a battery of verbal report instruments and participated in two behavioral assessment tests. Measures of avoidance/escape behavior, cardiac response, level of behavioral skill, state anxiety, and positive and negative self-statements during performance were collected. Significant differences across response domains were found between the circumscribed social phobia and the generalized groups. Most of the distinctions were between individuals with circumscribed social phobia and those with both generalized social phobia and avoidant personality disorder, with the former group having less overall psychopathology. In addition, there was substantial overlap of problems between generalized social phobia individuals with and without avoidant personality disorder. Implications for the conceptualization of social phobia are discussed in terms of the differences among social phobia subtypes.

Adult↗

Mechanism of action of Roter (bismuth subnitrate) in patients with duodenal ulcer disease and healthy volunteers.

The effects of Roter (compound bismuth subnitrate) on antacid activity and mucosal prostaglandin E2 (PGE2) synthesis were variously investigated in patients with duodenal ulcer disease and healthy volunteers. Roter had a significant but small antacid activity with a buffering capacity of 10.9 mmol per tablet. In healthy volunteers, this was assessed by 24 h gastric pH monitoring on matched days with and without Roter treatment. The percentage of time that gastric pH was above 3 and the time after a standard meal that the pH was above 3, were both significantly increased by treatment with Roter (II tds post-cibal) (P less than 0.01). Endogenous PGE2 synthesis was measured in endoscopic duodenal biopsies taken both before and after Roter treatment in patients with acute untreated duodenal ulceration. There was a significant deficiency of mucosal PGE2 synthesis in untreated patients compared with controls (P less than 0.005). However, following 4 weeks' treatment with Roter, there was a 90% rate of healing accompanied by a significant increase in PGE2 synthesis (P less than 0.05) up to control levels. These findings suggest that Roter heals by the combined effects of a modest antacid neutralizing capacity and the ability to restore mucosal prostaglandins to normal levels, thereby mediating prostaglandin-dependent defence mechanisms.

Adult↗