Biomedical subjects

C M Furnival

Publications and source records attributed to C M Furnival.

53 records · Page 3Linked to original sources

PubMed1976

The mechanism of impaired coagulation after partial hepatectomy in the dog.

Coagulation mechanisms were examined in the dog after a 70 per cent hepatectomy and the additional effect of varying periods of ischemia on the liver remnant. Dogs were submitted to a 70 per cent partial hepatectomy, and the liver remnant was rendered ischemic by occluding the vascular inflow. Portal decompression during ischemia was accomplished by allowing portal venous flow through the lobes subsequently resected. Dogs in the control group, those undergoing hepatectomy alone and those undergoing hepatectomy together with 60 minutes of ischemia time exhibited a fall in hemoglobin and hematocrit values, a transient leukocytosis, a small increase in kaolincephalin clotting time and a decline in platelet count but no significant thrombocytopenia. Prothrombin time was changed in dogs undergoing hepatectomy, but this was not affected by ischemia. The characteristic rise in plasma fibrinogen postoperatively was abolished, and fibrinogen levels were lower in dogs undergoing hepatectomy alone and fell significantly in dogs subjected to 30 to 60 minutes of ischemia of the liver remnant. Factors V and VII were decreased after hepatectomy, and Factor V was more severely reduced after 30 to 60 minutes of ischemia. There was no overt bleeding tendency. In ten dogs, the liver remnant was subjected to ischemia for 75 minutes. Four of these died within three days of operation, two with severe hypoglycemia and two with postoperative bleeding. All six surviving dogs exhibited gross coagulation defects. Prothrombin time rose, kaolin-cephalin clotting time increased and platelets fell to a greater degree than in any of the other dogs. Plasma fibrinogen level showed a profound fall, as did Factor V, the magnitude of these changes being greater than after a shorter period of ischemia. Factor VII was also decreased, but this did not appear to be related to the ischemic interval. In the clinical situation in which intrinsic coagulation mechanisms are shown to be impaired, treatment with Factor V and VII concentrates may be the best way of correcting the coagulation defect.

Animals↗

PubMed1976

Radioactive technetium phosphate bone scanning in preoperative assessment and follow-up study of patients with primary cancer of the breast.

Seventy-five female patients with early primary cancer of the breast were studied by bone scanning with 99mTc labeled phosphate at the time of initial presentation and serially during follow-up examination. Eleven patients had an abnormal bone scan at the time of presentation. During follow-up periods, which have ranged from three to 34 months with a mean of 16 months, abnormal bone scans have developed in a further 13 patients. To date, nine of the 24 patients with an abnormal bone scan have died, while only one of the 51 with a persistently normal scan has died. It is concluded that an abnormal bone scan carries a significant risk of earlier death due to metastatic disease.

Adult↗

PubMed1975

Aspiration cytology in breast cancer. Its relevance to diagnosis.

Fine-needle aspiration cytology as a routine method in the management of breast disease was assessed in 237 patients presenting with a breast lump. The diagnostic accuracy of the method was 95.5% in both benign and malignant lesions. Fine needle aspiration is a safe procedure with an accuracy exceeding that of other diagnostic methods; it does not replace frozen-section histology but improves the management of breast disease by giving accurate preoperative diagnosis.

Adolescent↗

PubMed1975

The effect of hepatic ischaemia on liver function and the restoration of liver mass after 70 per cent partial hepatectomy in the dog.

Partial hepatectomy was performed in dogs either as the only procedure or following a period of ischaemia of liver remnant produced by inflow occlusion for periods of 30-60 minutes before partial hepatectomy. Temporary portal decompression was maintained through the portion of liver subsequently excised. 1. Survival in dogs subjected to partial hepatectomy and ischaemia to the liver remnant was similar to that in animals after partial hepatectomy alone. 2. Metabolic changes were similar in both groups but dogs submitted to partial hepatectomy and ischaemia to the remnant had higher serum alkaline phosphatase and alanine amino-transferase levels with increased bromsulphthalein in the fourth to sixth post-operative weeks. 3. Replacement of liver mass proceeded rapidly in all groups of animals. It is concluded that ischaemia of the liver remnant for up to 60 minutes preceding partial hepatectomy in the dog is consistent with survival and produced little change in postoperative liver function or in the rate of restoration of liver mass.

Alanine Transaminase↗

PubMed1973

Chronotropic and inotropic effects on the dog heart of stimulating the efferent cardiac sympathetic nerves.

1. The chronotropic and inotropic responses of the dog heart to stimulation of the ansae subclaviae were studied.2. The maximum rate of rise of pressure in the left ventricle (dP/dt max) was used as an index of the inotropic changes.3. In experiments in which the secondary inotropic effects of changes in heart rate and blood pressure were prevented it was shown that, using stimuli which produced the same chronotropic response, stimulation of the left ansa subclavia resulted in an inotropic change which was about eight times greater than that which resulted from stimulation of the right ansa subclavia.4. In experiments in which heart rate and blood pressure were allowed to change freely it was shown that the secondary inotropic effects of changes in blood pressure and heart rate amounted to about 70% of the total inotropic change when the right ansa subclavia was stimulated and about 20% of the total change when the left ansa subclavia was stimulated.

Animals↗

PubMed1973

The inotropic effect on the heart of stimulating the vagus in the dog, duck and toad.

1. The chronotropic and inotropic effects of stimulating the vagus on the hearts of the dog, duck and toad were studied.2. The maximum rate of rise of pressure in the left ventricle (dP/dt max) measured at a constant heart rate and mean aortic pressure was used as an index of the inotropic changes.3. The sensitivity of dP/dt max as an index of inotropic changes brought about by stimulating the vagus was established in the toad where a 49% reduction in heart rate was associated with a 30% reduction in dP/dt max.4. In the dog stimulation of the vagus resulted in a reduction in heart rate of 38% and only a small reduction in dP/dt max of 6%.5. Results similar to those found in the dog were obtained in the duck where the reduction in heart rate of 44% was associated with reduction in dP/dt max of only 3%.6. It is concluded that the vagus has only a small and negligible negative inotropic effect on the ventricles of the dog and duck.

Animals↗

PubMed1971

The inotropic and chronotropic effects of catecholamines on the dog heart.

1. The chronotropic and inotropic responses of the denervated dog heart to intravenous infusions of noradrenaline, adrenaline and isoprenaline were studied.2. The maximum rate of rise of pressure in the left ventricle of the heart, (dP/dt max) measured at a constant heart rate and mean systemic arterial pressure during each series of infusions, was used as an index of inotropic changes (Furnival, Linden & Snow, 1970).3. The order of potency of the catecholamines in producing both chronotropic and inotropic effects was isoprenaline > adrenaline > noradrenaline.4. For the same increase in heart rate produced by an infusion of a catecholamine, noradrenaline caused a greater inotropic effect than adrenaline, which in turn caused a greater increase than isoprenaline.5. The chronotropic and inotropic effects of noradrenaline were potentiated by an intravenous injection of cocaine HCl (5 mg/kg), whereas those of isoprenaline were unchanged.6. The relative difference between the responses to noradrenaline and isoprenaline was abolished by an intravenous injection of cocaine HCl.7. It is concluded that the different relative chronotropic and inotropic effects of isoprenaline and noradrenaline are due to the greater uptake of noradrenaline by sympathetic nerve endings in the sinu-atrial node than in the muscle of the left ventricle.

Animals↗

PubMed1971

Reflex effects on the heart of stimulating left atrial receptors.

1. Stimulation of left atrial receptors, by distension of the pulmonary vein/left atrial junctions, is known to cause a reflex increase in heart rate; the efferent pathway is known to be solely in the sympathetic nerves.2. In expectation of a concomitant positive inotropic response the effect of stimulating the left atrial receptors on the inotropic state of the left ventricle was studied, using as a known sensitive index of inotropic changes the maximal rate of rise of pressure in the left ventricle (dP/dt max).3. Stimulation of left atrial receptors resulted in an increase in heart rate but there were no significant concomitant changes in dP/dt max.4. It is concluded that activity in this discrete efferent pathway does not include an inotropic effect on the left ventricle and therefore the reflex involves only those sympathetic nerves which innervate the sinu-atrial node.5. The possible function of atrial receptors in the regulation of heart volumes is discussed.

Animals↗

PubMed1970

Inotropic changes in the left ventricle: the effect of changes in heart rate, aortic pressure and end-diastolic pressure.

1. Under conditions where heart rate, mean aortic pressure and enddiastolic pressure in the left ventricle are held constant, the intravenous infusion of isoprenaline is accompanied by large changes in dP/dt max in the left ventricle.2. Under similar conditions, during stepwise increments in the rate of infusion of isoprenaline the changes in dP/dt max (measured at a constant paced heart rate) were proportional to changes in the free (intrinsic) heart rate. It is concluded that dP/dt max is a quantitative index of inotropic changes in the left ventricle.3. In comparison to dP/dt max, three other variables which have been used to indicate inotropic changes in the heart (peak pressure in the left ventricle, duration of systole and stroke work at constant end-diastolic pressure), were shown to be unreliable indices of inotropic changes.4. Using dP/dt max to indicate inotropic changes, alteration in the heart rate while mean aortic pressure and end-diastolic pressure in the left ventricle were held constant, and in mean aortic pressure while heart rate ane end-diastolic pressure in the left ventricle were held constant, were each shown to be accompanied by small inotropic changes in the heart.5. Under similar conditions, changes in end-diastolic pressure in the left ventricle alone were not accompanied by inotropic changes as indicated by dP/dt max.

Animals↗

PubMed1970