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Biomedical subjects

L D MacLean

Publications and source records attributed to L D MacLean.

At least 91 records · Page 5Linked to original sources
PubMed1976

Lactate metabolism in the dog during shock from hemorrhage, cardiac tamponade or endotoxin.

The elevated arterial lactate concentration in shock was investigated by measuring lactate production and clearance rate using a constant infusion of 14C-labeled lactate. In addition, the pathways of lactate metabolism were characterized by determining the percentage of lactate under-going oxidation and the percentage of the total carbon dioxide production which was derived from lactate. These measurements were performed on 16 normal dogs and on 23 dogs in a state of shock. Shock was induced by hemorrhage in ten, by controlled cardiac tamponade in seven and by endotoxin injection in six. In all of the dogs in a state of shock, there was a statistically significant increase in both the arterial lactate concentration and lactate turnover, while the lactate clearance decreased significantly. The percentage of the arterial lactate which underwent oxidation remained normal. The percentage of the total carbon dioxide production which was derived from lactate increased significantly, p less than 0.05, from 4.7 per cent in the normal dogs to 22.7 per cent in the dogs in a state of shock. Since both oxygen uptake and carbon dioxide production remain unchanged in shock, these data are consistent with an increased metabolism of substrates which from pyruvate and lactate as intermediary metabolites, that is, carbohydrates and certain amino acids, with a concomitant decrease in the metabolism of substrates which do not form pyruvate, that is, free fatty acids. In both the normal and shocked dogs, the arterial lactate concentration rose as the lactate production rate increased. Therefore, the elevated arterial lactate in shock was due to an increase in the lactate production and not to a lack of oxygen.

Animals↗
PubMed1976

A multiparametric computer analysis of carcinoma of the colon.

From 1957 to 1973, 656 patients with carcinoma of the entire colon, excluding those with carcinoma of the rectum, were reviewed with the aid of a computer. Of 457 patients, 69.7 per cent were observed for a minimum of five years. Sixty-five per cent of the lesions were located in the cecum or sigmoid colon. In patients with type A lesion, the five year plus survival rate was 71.15 per cent while, in patients with type D lesions, the five year plus survival rate was zero per cent. Patients who presented with intestinal obstruction had a significantly lower five year survival rate. Roentgenographic visualization of the cecum was significantly less accurate in demonstrating carcinoma when compared with that of the sigmoid colon. An emergency surgical procedure had a significantly higher operative mortality than did elective procedures. In both groups of patients undergoing emergency and elective operations, primary resection and anastomosis led to similar operative mortality rates, although staged procedures resulted in the lowest operative mortality in both groups. In the group of patients who had elective operations, resection an primary anastomosis led to a significantly lower wound infection and fistula rate when compared with the group of patients who had emergency procedures. In comparison with other series, no improvement in survival was illustrated in patients with carcinoma of the colon. The use of new modalities of adjuvant therapy, such as radiotherapy or chemotherapy, or both, actually should be evaluated.

Adult↗
PubMed1975

Diseases associated with specific HL-A antigens.

Significantly increased prevalences of particular HL-A antigens have been reported for many human diseases. The correlation is particularly striking in ankylosing spondylitis, Reiter's syndrome, psoriasis and some immunopathic disorders, so that HL-A typing may be of great value in diagnosis. The possible mechanisms whereby these associations may occur suggest the cause of certain disorders, and further investiatation will likely help in the understanding of the pathogenesis of many diseases.

Arthritis↗
PubMed1975

Massive spontaneous portal-systemic shunting without varices.

Using umbilical vein portal phlebography, a group of patients, often with previously unsuspected liver disease or portal hypertension, have been identified with massive spontaneous portal-systemic shunts. In all cases, the collateral circulation was a single large vessel. The splenoadrenorenal, umbilical vein, or inferior mesenteric vein routes were the common pathways. These natural shunts were functional and effective in the alleviation of portal hypertension without evidence of esophageal varices or other collaterals. Portal flow was usually retrograde, perhaps contributing to the small atrophic liver seen in all patients. Six such patients were seen in the last 40 studied. This phenomenon may be more common than suspected in the cirrhotic population and account in part for differences in natural history, complications, and results of surgical therapy.

Adolescent↗
PubMed1975

The management of bleeding acute gastric erosions: the role of gastric hypothermia.

Eighty-eight consecutive patients with bleeding acute gastric erosions were reviewed with the aid of a computer. Of the eroisons, 31-8 per cent were related to the ingestion of ulcerogenic drugs and 40-9 per cent were associated with surgery and sepsis. The overall mortality was 20-5 per cent. Endoscopy was the most effective diagnostic examination. Conservative management was effective in the treatment of bleeding erosions due to the ingestion of ulcerogenic drugs. Gastric cooling successfully arrested haemorrhage from bleeding erosions due to surgery and sepsis.

Acute Disease↗
PubMed1975

Host resistance in sepsis and trauma.

Host resistance to infection was measured by the in vivo response to 5 delayed hypersensitivity antigens and to sensitivity and challenge by dinitrochlorobenzene (DNCB) in 55 seriously ill or injured patients and in 50 preoperative patients. A close correlation between infections, septicemia, death related to infection and anergy was found in the postoperative and post injury patients and was predictive of these complications in the patients studied preoperatively. Decreased body cell mass was noted in both the anergic and non-anergic patients which was consistent with protein-calorie malnutrition but the two groups were not significantly different. A serum factor which inhibited cellular immunity in vitro was found in 4 patients. This factor disappeared in the two patients who recovered. The study suggests the therapeutic value of the in vivo measurement of delayed hypersensitivity in seriously ill and especially preoperative patients in whom specific or non-specific stimulation of cell mediated immunity might alter the risk of infection.

Adolescent↗
PubMed1975

Prophylactic antibiotic therapy in surgery.

Prophylactic (preventive) antibiotic therapy initiated preoperatively, with antibiotics administered in moderately high dosage for short periods, is recommended on the basis of experimental and prospective, randomized clinical trials for patients who require surgery that is likely to expose tissue planes to contamination. The value of prophylactic antibiotics in clean operations is not presently supported but must be considered in patients with decreased resistance and in those in whom infection of a prosthesis would have catastrophic results. In these patients topical antibiotics might prove useful and less dangerous. It is clear that surgical technique remains an important but as yet unmeasured factor in wound infection.

Ampicillin↗
PubMed1975

Impedance phlebography: accuracy of diagnosis in deep vein thrombosis.

In an evaluation of the diagnostic accuracy of impedance phlebography for the diagnosis of deep vein thrombosis, 51 limbs in 32 patients were examined simultaneously by impedance phlebography and by venography. The impendance diagnosis and accurate in 47 limbs, erroneous in 2 and inconclusive in 2; the overall accuracy was 92%. Simultaneous clinical diagnosis yielded an accuracy of 53%. The method requires full cooperation by the patient and meticulous attention to the details of the test by the physician or technician performing the examination.

Aged↗
PubMed1975

Results of cholecystectomy in 1000 consecutive patients.

Analysis of the results of cholecystectomy in 1000 consecutive patients revealed an overall mortality of 0.6%; among patients who underwent cholecystectomy only, there were no deaths. Wound infection occurred in 3.4% of all patients but the rate exceeded 8% among those in whom another procedure was performed or there was acute cholecystitis. Cephaloridine given prophylactically was useful in decreasing the infection rate in the two latter groups. Cystic duct cholangiography, used in 193 patients, increased the rate of stone retrieval from the bile ducts from 41 to 63%, but the incidence of both false-negative and false-positive cholangiograms was disturbingly high. Exploration was performed on clinical grounds despite a normal cholangiogram in 15 patients, with 5 positive results. Common duct exploration was productive 41% of the time when clinical judgement without cholangiography was used. While cystic duct cholangiography is useful, improvements in reliability are imperative and probably feasible, in view of the results achieved in the operating room and those in departments of radiology.

Acute Disease↗