Cardiovascular effects of and interaction between calcium blocking drugs and anesthetics in chronically instrumented dogs. II. Verapamil, enflurane, and isoflurane

The effects of enflurane and isoflurane on the cardiovascular system and cellular calcium kinetics are somewhat different. Consequently, the interaction with the calcium channel blocking drug, verapamil, may also differ. In order to compare the anesthetics, the authors studied the effects of two infusion doses of verapamil (which produced plasma levels of 90 and 180 ng X ml-1) on cardiovascular dynamics and regional blood flow in awake dogs. On two other days, in the same dogs, the effects of approximately 1.1 and 2 MAC enflurane and isoflurane were first studied and then the same verapamil dose regimens while the same anesthetic concentrations were maintained. Verapamil produced only increases in heart rate and the P-R interval in the awake animal. The high dose of both anesthetics markedly decreased mean aortic pressure and left ventricular rate of tension development (dP/dt), and increased heart rate. However, only enflurane also decreased myocardial segment length shortening and increased left atrial pressure. Neither anesthetic alone affected coronary or renal blood flow, while both increased carotid blood flow at the low dose. Verapamil infusion during 1.2 MAC enflurane was more depressant than during 1.2 MAC isoflurane, but the combination of verapamil with 2 MAC concentration of both anesthetics was equally depressant. Both doses of both anesthetics increased plasma verapamil levels compared with the same verapamil dosing regimen awake. When these results are compared with those previously reported for halothane, the effects of verapamil during all three anesthetics are more similar than different.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular effects of and interaction between calcium blocking drugs and anesthetics in chronically instrumented dogs. I. Verapamil and halothane

In order to assess the interaction between halothane and verapamil on the cardiovascular system, mongrel dogs were instrumented so that the following measurements could be made awake and under the influence of the drugs: aortic, left ventricular, and left atrial blood pressures; myocardial segment length shortening; heart rate and rhythm; and coronary, carotid, and renal blood flows. The effect of two infusion doses of verapamil (3 micrograms X kg-1 X min-1 and 6 micrograms X kg-1 X min-1 after 200 micrograms X kg-1 bolus) were examined awake. On a different day in the same dogs, two concentrations of halothane (1.2-low and 2.4-high % end-tidal) and the effect of the two infusion doses of verapamil during low and high halothane were studied. Thirty minutes of either infusion dose of verapamil produced only heart rate and electrocardiographic P-R interval increases in conscious dogs. Halothane produced dose-related decreases in mean aortic pressure, left ventricular maximum rate of tension development (dP/dt), and segment length shortening and increases in heart rate and left atrial pressure. Carotid blood flow was increased by low halothane concentrations and returned to control with high halothane concentrations. There were no significant changes in coronary or renal blood flow produced by halothane. Verapamil infusion during low halothane concentration produced minimal effects. However, both the 3 and 6 micrograms X kg-1 X min-1 verapamil doses further depressed hearts already depressed by the high concentrations of halothane and decreased renal and carotid blood flows.(ABSTRACT TRUNCATED AT 250 WORDS)

Pyoderma gangrenosum after cholecystectomy

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Mechanism of malignant hypercalcaemia in carcinoma of the breast

To investigate the mechanisms of hypercalcaemia in carcinoma of the breast, 22 patients with hypercalcaemia due to metastatic carcinoma were studied and the findings compared with those obtained in normal subjects and patients with benign and malignant breast disease without hypercalcaemia. As expected, patients with metastases of bone showed biochemical evidence of increased bone resorption. Whereas all patients with hypercalcaemia had skeletal metastases, not all patients with skeletal metastases had hypercalcaemia despite considerable degrees of bone resorption. The presence of hypercalcaemia was associated with a significant increase in renal tubular reabsorption of calcium (p less than 0.001) and decreased reabsorption of phosphate (p less than 0.001) despite adequate rehydration of patients. These studies suggest that increased renal tubular reabsorption of calcium, possibly mediated by a humoral factor with activity similar to that of parathyroid hormone, contributes appreciably to the hypercalcaemia of malignant breast disease.

Treatment of oesophageal perforation by intubation

The mortality following oesophageal perforation ranges from 25% to 100% depending on the delay in diagnosis and treatment. Although the treatment recommended for thoracic perforations is emergency thoracotomy and suture of the perforation, the avoidance of this approach in elderly patients is desirable. We therefore describe 6 cases of oesophageal perforation which were treated by insertion of a Celestin tube at laparotomy.

Cystadenoma of the pancreas--an unusual presentation

Cystadenoma is a rare lesion of the pancreas. A case is reported in which the tumour was initially misdiagnosed as a pseudocyst and inappropriate surgery performed. The patient subsequently presented with gastro-intestinal haemorrhage and the tumour was resected. The diagnosis and management of cystic lesions of the pancreas are discussed, stressing the need for complete pre-operative investigation in order that incorrect treatment is avoided.

Elevated gastric juice enzymes--a marker for increased gastric cancer risk?

Measurement of beta-glucuronidase and lactic dehydrogenase in the fasting gastric juice of dyspeptic patients is a useful test for gastric cancer, but about 10% of patients tested have positive results without a demonstrable carcinoma. We have compared the histological features of multiple endoscopic gastric biopsies from 17 such patients with apparently false positive enzyme tests with gastric biopsies from 17 age and sex matched patients with negative enzyme tests. Epithelial dysplasia, a precancerous lesion, was found in 3 patients with positive enzyme tests but was not found in those with negative enzyme tests. Sulphomucin-containing intestinal metaplasia, another lesion which is associated with carcinoma of the stomach, was found in 8 patients with a positive enzyme test (including all 3 with dysplasia) but in only one patient with a negative enzyme test. These findings suggest that patients with positive gastric juice enzyme tests who do not have an established carcinoma form a group who are at increased risk of developing gastric cancer in the future and who may be worthy of long-term follow-up.

The nature of enhanced natural killer lymphocyte cytotoxicity during anesthesia and surgery in patients with benign disease and cancer

This study was instituted to determine the mechanism of enhanced natural killer (NK) lymphocyte activity during surgery. Natural cytotoxicity of whole blood to K562 target cells was assayed before anesthesia and during anesthesia and surgery in patients with benign and malignant gastrointestinal disease. Those patients with benign conditions and localized primary tumors showed enhanced NK lymphocyte cytotoxicity during surgery (p less than 0.025 and p less than 0.0025, respectively) but not patients with disseminated tumors. In patients with localized tumors, enhancement of NK lymphocyte cytotoxicity was an interferon-independent phenomenon but appeared to be related to a significant rise in the percentage of cells bearing the Leu 7 monoclonal antibody marker for NK cells (p less than 0.02). Exogenous leukocyte interferon caused further enhancement of NK cytotoxicity in patients with benign disease and some cancer patients. Enhancement of NK lymphocyte activity during surgery may be of significance in reducing tumor metastases by stimulation of natural cytotoxic mechanisms to circulating tumor emboli.

The measurement of depression: enhancing the predictive validity of the Beck Depression Inventory

Investigated whether the predictive validity of the Beck Depression Inventory (BDI) could be enhanced by having Ss complete the BDI under regular vs. a 6-week projected response set. Six hundred students participated in the initial screening phase, in which they were administered the BDI under both standard and projected instructional sets. Two groups were identified: High initial-high projected (N = 17) and high initial-low projected (N = 20). Additionally, a low initial-low projected control group (N = 13) was selected. At 5 to 6 weeks follow-up, these Ss again completed the BDI and were administered the Hamilton Rating Scale for Depression as a criterion check. Except for the low-low group, which changed little at follow-up, the final BDIs were lower than initial BDIs. However, projected BDIs provided for more accurate classification than the initial screening BDI. Also, projected BDI scores were significant predictors of both final BDIs and the Hamilton ratings, whereas initial BDIs did not correlate significantly with either criterion. These data suggest that projected BDI protocols could serve as a practical alternative to more costly or time-consuming methods of selection of research populations.

Visuospatial impairment in Parkinson's disease. Role of perceptual and motor factors

We investigated the role of perceptual and motor factors in visuospatial impairment in 30 patients with Parkinson's disease (PD) and 30 matched controls. All subjects were administered visuospatial tests, which included "visuoperceptual" tasks, requiring minimal motor responses, and "visuomotor" tasks. The performance of patients with PD was considerably impaired on several tasks from both groups, and this impairment was not related to depression or intellectual impairment. Patients in stage 3 of the disease tended to show the greatest impairment. Those in stage 1 (unilateral symptoms), however, tended to show more impairment than those in stage 2.

Out-of-hospital cardiac arrest: factors associated with survival

One hundred eighty-seven cases of cardiac arrest of presumed cardiac etiology were analyzed to determine factors associated with successful out-of-hospital management by paramedic teams. Field and in-hospital records were reviewed to determine the response time of the advanced life support team, the ECG rhythm on arrival, the presence of paramedics on scene at the time of the arrest, whether bystander CPR had been initiated, and the eventual outcome of the resuscitation attempt. A significant difference in survival-to-leave-hospital was seen in patients in whom ventricular fibrillation or ventricular tachycardia (VF/VT) was present on arrival (15.3%) compared to patients with asystole, idioventricular rhythms, blocks, or electromechanical dissociation (3.4%). Survival rates in patients in whom CPR was being performed by a bystander were 24% in the VF/VT group and zero in the "OTHER" rhythms group. When the advanced life support team arrived in less than four minutes, survival rates in the VF/VT group and "OTHER" rhythms group were 23.1% and 7.7%, respectively. When the field team arrived in less than four minutes and a bystander was performing CPR, the survival rates were 42.9% in the VF/VT group and 15.8% in the "OTHER." These data suggest that efforts to improve survival from out-of-hospital cardiac arrest in a community should be directed toward public education, reduction in response times of paramedic units, and lay CPR training.

Stimulation of glycosaminoglycan production and lysosomal activity of human synovial cells in culture by low environmental pH

Glycosaminoglycan production, acid hydrolase activity, proliferation, and morphology were examined in human synovial cells subjected to low environmental pH. The amount and the molecular size of newly synthesised glycosaminoglycan (GAG) were increased without significant change in the rate of cell proliferation. Lowered pH produced an increase in the size of cytoplasmic organelles. Some of these possessed ultrastructural features of lysosomes, but others were clearly nonlysosomal and were of uncertain identity. Intracellular activity of the lysosomal acid hydrolase N-acetyl-beta-glucosaminidase (NAG) was not altered by low pH, but a marked increase occurred in extracellular NAG activity, indicating enhanced release.

The haemodynamic effects of intraaortic versus intravenous administration of protamine for reversal of heparin in man

A recent report suggests that there may be advantages of intraaortic (IA) versus intravenous (IV) administration of protamine for reversal of heparin at the end of cardiopulmonary bypass. Because complete haemodynamic measurements were not performed in that study, we prospectively and randomly assessed the effects of protamine sulphate administered via either route. Patients were studied in the period immediately following cardiopulmonary bypass. Heparin, 300 units . Kg-1, plus 150 units . Kg-1 when required, was administered to keep the activated clotting time greater than 400 sec. Protamine 3 mg . Kg-1 was injected over 30 sec. intravenously in the IV group (n = 5) and into the ascending aorta in the IA group (n = 5). There was a significant decrease in arterial blood pressure (28.6 per cent) from 109.2 +/- 5.6 mmHg (S.E.) systolic to 78.0 +/- 9.0 mmHg observed in the IA group one minute post protamine, which returned to baseline by 2.5 min (analysis of variance p less than 0.05). No significant hypotension was observed in the IV group. There was no significant change in heart rate, left atrial pressure, central venous pressure, systemic vascular resistance or cardiac index with either IA or IV protamine. In contrast to our recent study in pigs there was no significant change in pulmonary artery pressure, pulmonary vascular resistance or cardiac output with protamine. Results indicate that there are no haemodynamic benefits of IA vs IV injection of protamine.

The hemodynamic effects of intra-aortic versus intravenous administration of protamine for reversal of heparin in pigs

The hemodynamic effects of intra-aortic (IA) versus intravenous (IV) administration of protamine for reversal of heparin were studied in pigs. The animals were anesthetized with sodium thiopental, nitrous oxide, oxygen, and halothane. Twenty minutes after heparinization (3 mg/kg) the following hemodynamic parameters were measured: heart rate, arterial pressure, pulmonary artery pressure (PAP), left ventricular end-diastolic pressure, and cardiac output. Protamine sulfate (3 mg/kg) was injected over 30 seconds IV in Group I (five pigs) and into the ascending aorta (IA) in Group II (five pigs). After injection, the above measurements were repeated at 1.0, 2.5, 5, and 15 minutes. The hemodynamic effects of intravenous protamine (3 mg/kg) without prior heparinization were studied in Group III (four pigs). Groups I and II experienced a decrease in cardiac output (Group I, 14%; Group II, 29%) and a marked increase in PAP (Group I, 78%; Group II, 79%) and pulmonary vascular resistance (PVR) (Group I, 174%; Group II, 559%) which peaked at 1 minute after protamine injection (p less than 0.05). Cardiac output, PAP, and PVR returned to baseline within 15 minutes. Heart rate, arterial pressure, left ventricular end-diastolic pressure, and systemic vascular resistance (SVR) were unchanged. No hemodynamic abnormalities occurred in animals injected with protamine alone (Group III). It is concluded that IV or IA administration of protamine causes marked hemodynamic changes in heparinized pigs. This does not confirm a recent clinical study reporting stable hemodynamics after IA administration of protamine. The lack of circulatory effects of protamine in unheparinized pigs suggests that a protamine-heparin interaction may be involved.

Is new always better? A comparison of an established teaching method with a new teaching method in a surgical course

A comparison has been made between the effectiveness of a problem-solving exercise and a formal lecture on medical students' learning during their surgical attachment. The format of a clinical trail has been adapted. No difference has been shown in the knowledge conveyed by the two methods, although the students preferred the problem-solving exercise. No assessment has been made in this study of differences in the students ability to solve problems after exposure to different methods of teaching.

Effects of thiopentone on the canine coronary circulation in acute experimental myocardial ischaemia

Acute myocardial ischaemia was induced in five greyhounds by ligation of the anterior descending branch of the left main coronary artery. Changes in oxygen availability and consumption in the ischaemic area in response to thiopentone 10 mg kg-1 were compared with corresponding changes in non-ischaemic myocardium supplied by the circumflex artery. Despite a 40% reduction in arterial pressure, there were no significant changes in the oxygen availability/consumption ratio in either normal or ischaemic areas.

Rectal strictures associated with the intra-uterine contraceptive device

Two cases of stricture of the mid-rectum following extensive pelvic cellulitis due to the use of an intra-uterine contraceptive device (IUCD) are presented. The resulting dense circumferential extrarectal strictures failed to respond to treatment by proximal colostomy and antibiotic therapy and required difficult corrective resection. These are contrasted with an example of the more common upper rectal strictures associated with intraperitoneal sepsis of gynaecological origin, in this case pyosalpynx. Circumferential and transmural spread of inflammation tends to be limited by peritoneal reaction and the resulting strictures (which may be radiologically as severe as those in the mid-rectum) are often readily managed by simple removal of the source of infection. Thus, it appears that simple anatomical factors may be responsible for the differing pathologies seen in the two sites, and different management problems encountered within the two types of strictures.

Gastric-juice enzymes--an aid in the diagnosis of gastric cancer?

Lactic dehydrogenase (LDH) and beta-glucuronidase concentrations were measured in the resting gastric juice of 113 patients presenting with dyspepsia. All patients were investigated by double-contrast barium meal, endoscopy with biopsy, and, when appropriate, by laparotomy. In all patients tested there was a positive correlation between LDH and beta-glucuronidase concentrations. An index derived from the two enzyme activities correctly predicted the presence of gastric carcinoma in 41 out of 42 cases, and identified the only 2 cases of early gastric cancer in the series. There were 13 (11.5%) false-positive results, all in cases with extensive intestinal metaplasia, a change which may be associated with an increased risk of gastric malignancy. The measurement of gastric-juice enzymes is useful in the diagnosis of gastric cancer and may be of value in the identification of high-risk groups. The test is easily performed, inexpensive, and reproducible.

Halothane improves the balance of oxygen supply to demand in acute experimental myocardial ischaemia

Acute myocardial infarction was induced by ligation of the anterior descending branch of the left main coronary artery in greyhound dogs anaesthetized with pentobarbitone. Blood flow in the area of ischaemia was measured by xenon clearance and compared with flow in the circumflex artery measured with electromagnetic flow meters. Halothane 1% produced an approximate 40% reduction in flow to both ischaemic and normal areas in association with a 20% reduction in collateral perfusion pressure and a 40% reduction in mean arterial pressure. Comparison of the percentage change in the ratio of oxygen availability/consumption in response to halothane revealed a significant difference between the ischaemic and the normal areas. The former increased to 113 +/- 9.3% (mean +/- SEM) whilst the latter decreased to 91 +/- 5.02%. This suggests that, in the non-failing heart, halothane improves oxygenation in areas of acute myocardial ischaemia.

A program for correction of ear perforations in Navajo Indian children

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Vitamin C and acute illness in Navajo schoolchildren

To evaluate earlier observations, including our own, showing usefulness of vitamin C for managing the common cold, we performed a double-blind trial of vitamin C versus placebo in 868 children. There was no difference in number becoming ill (133 versus 129), number of episodes (166 versus 159) or mean illness duration (5.5 versus 5.8 days) between the groups. Children receiving vitamin C had fewer throat cultures yielding beta-hemolytic streptococcus (six versus 13, P less than 0.10), but no difference in overall complicated illness rate (24 versus 25). Plasma ascorbic acid levels were higher in the vitamin group 24 to 26 hours after supplementation (1.28 versus 1.04 mg per 100 ml, P less than 0.01). Children with high plasma ascorbic acid concentrations had longer mean illness (6.8 versus 4.0 days, P less than 0.05) than those with low levels. Vitamin C does not seem to be an effective prophylactic or therapeutic agent for upper respiratory illness.

Clearance of Fe59-labelled erythrocytes from normal and inflamed rabbit knee joints. II. Autoradiographic and histological studies

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