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Biomedical subjects

L D MacLean

Publications and source records attributed to L D MacLean.

At least 73 records · Page 4Linked to original sources
PubMed1979

Alterations of hepatic triglyceride in patients before and after jejunoileal bypass for morbid obesity.

The effect of obesity and jejunoileal bypass on the amount and composition of hepatic lipid and the relationship of adipose tissue fatty acids, body weight, and rate of weight reduction to hepatic triglyceride (TG) were investigated in 16 patients before and at various times after jejunoileal bypass. Liver and adipose tissue biopsy sections were taken at surgery and at various times thereafter. Hepatic lipid was measured and the composition of triglyceride fatty acids (TGFA) compared with that of adipose tissue. Liver TG increased by an average of 2.5-fold during the period of rapid weight loss and decreased during the period of stable weight, but remained above control values. There was no relationship between concentration of liver TG and body weight or rate of weight reduction. The hepatic TGFA composition at surgery and during the period of stable weight resembled that of adipose tissue. During the period of rapid weight loss the composition of hepatic TGFA was markedly different, showing an increase in palmitic (16:0, P less than 0.01), palmitoleic (16:1, P less than 0.05), and oleic acids (18:1, P less than 0.05) and a decrease in linoleic acid (18:2, P less than 0.001). These changes could not be accounted for by a preferential absorption or mobilization of 16:0, 16:1, and 18:1, or by an increased utilization of 18:2 by the liver. It is proposed that an increased conversion of carbohydrate to fat occurs during the period of rapid weight loss when a relative excess of carbohydrate to amino acids results from an imbalance in the intestinal absorption of carbohydrate and protein.

Adipose Tissue↗
PubMed1978

Delayed hypersensitivity and neutrophil chemotaxis: effect of trauma.

To investigate alterations in host defense produced by trauma, skin testing with five standard recall antigens was done on admission and weekly on 53 patients with blunt trauma and seven with penetrating missile injuries, who then were classified as normal (N), 2 or more positive responses; relatively anergic (RA), one positive response; or anergic (A), no response. Neutrophil chemotaxis was tested 145 times in 32 patients. Degree of injury was assessed by assigning one point to pelvic fracture, long-bone fracture, head, chest, or abdominal injury, to a maximum of five. The A and RA patients had greater trauma, 3 vs. 1.6 for N, and a significantly increased rate of sepsis (p less than 0.005) and mortality (p less than 0.05). Incidence of anergy depended upon age and extent of trauma. Neutrophil chemotaxis in A and RA patients was significantly (p less than 0.001) worse at 96.7 +/- 2.4 mu and 99.8 +/- 1.7 mu compared to N, 113.2 +/- 1.7 mu, and controls 121 +/- 4 mu. With recovery, chemotaxis returned to normal. It is concluded that failure of delayed hypersensitivity responses follows trauma, is related to the severity of injury and age of patient, and is associated with an abnormality of neutrophil chemotaxis and increased rate of sepsis.

Adolescent↗
PubMed1978

Protein and fat utilization in shock.

A previous study demonstrated that in the dog, shock, regardless of its etiology, resulted in increased oxidative utilization of substrates which form lactate and pyruvate as intermediary metabolites. The study implied a concomitant decrease in free fatty acid oxidation, as the oxidative pathway of the latter does not involve the lactate-pyruvate step. To test this hypothesis, free fatty acid metabolism was investigated by infusing carbon-14 labelled fatty acid in 12 normal dogs, in nine animals in shock due to controlled cardiac tamponade, and in six animals with endotoxin shock. The shock state was characterized by significant (p less than 0.05) decrease both in arterial fatty acid concentration and in free fatty acid turnover. In addition, both the rate of free fatty acid oxidation and the percentage of the total CO2 derived from free fatty acid oxidation were significantly (p less than 0.05) diminished. In contrast, urea production rates were higher in shock, and the calculated maximum contribution of protein oxidation to total CO2 production rose from 23% in the control animals to 50% in the test groups.

Animals↗
PubMed1978

The anatomic and metabolic source of lactate in shock.

The size of the lactate pool in canine shock was measured directly by determining the lactate concentration of various organs. All organs tested, except skeletal muscle, had lactate concentrations similar to those of arterial blood. Skeletal muscles had much higher concentrations of lactate than did arterial blood. When 14C-labeled glucose was infused intravenously, it was concluded from the relative specific activities of glucose and lactate in blood that about one-third of lactic acid originates from blood glucose in shock. Only skeletal muscle had lower lactate specific activity than did blood. This is a possible indication that skeletal muscle is the site of production of lactate. Low glucose specific activity in muscle indicates massive glycogen breakdown, which probably serves as a metabolic precursor of lactate. Lactate production from amino acids produced by proteolysis could also play a role.

Amino Acids↗
PubMed1977

Delayed hypersensitivity: indicator of acquired failure of host defenses in sepsis and trauma.

Primary failure of host defense mechanisms has been associated with increased infection and mortality. Anergy, the failure of delayed hypersensitivity response, has been shown to identify surgical patients at increased risk for sepsis and related mortality. The anergic and relatively anergic patients whose skin tests failed to improve had a mortality rate of 74.4%, whereas those who improved their responses had a mortality rate of 5.1% (P < 0.001). This study documents abnormalities of neutrophil chemotaxis, T-lymphocyte rosetting in anergic patients and the effect of autologous serum. These abnormalities may account for the increased infection and mortality rates in anergic patients. Skin testing with five standard antigens has identified 110 anergic (A) or relatively anergic (RA) patients in whom neutrophil chemotaxis (CTX) and bactericidal function (NBF), T-lymphocyte rosettes, mixed lymphocyte culture (MLC), cell-mediated lympholysis (CML), and blastogenic factor (BF) were studied. The MLC, CML and BF were normal in the patients studied, and were not clinically helpful. Neutrophil CTX in 19 controls was 117.5 +/- 1.6 u whereas in 40 A patients, neutrophils migrated 81.7 +/- 2.3 u and in 15 RA patients 97.2 +/- 3.8 u (P < 0.01). In 14 patients whose skin tests converted to normal, neutrophil migration improved from 78.2 +/- 5.4 u to 107.2 +/- 4.0 u (P < 0.01). Incubation of A or control neutrophils in A serum reduced migration in A patients from 93 +/- 3.7 u to 86.2 +/- 3.5 u (P < 0.01) and in normals from 121.2 +/- 1.6 u to 103.6 +/- 2.6 u (P < 0.001). The per cent rosette forming cells in 66 A patients was 42.5 +/- 3.1 compared to 53.6 +/- 2.8 in normal responders (P < 0.02). Incubation of normal lymphocytes in anergic serum further reduced rosetting by 30%. Restoration of delayed hypersensitivity responses and concurrent improvement in cellular and serum components of host defense were correlated with maintenance of adequate nutrition and aggressive surgical drainage.

Adolescent↗
PubMed1977

Prognostic use of preoperative and immediate postoperative carcinoembryonic antigen determinations in colonic cancer.

Preoperative and postoperative carcinoembryonic antigen (CEA) concentrations are useful in predicting the likelihood of recurrence in patients undergoing curative operations for cancer of the colon. The incidence of recurrence was studied in three groups of patients followed for 6 to 18 months after such an operation: 36 patients (group 1) had preoperative and postoperative plasma CEA concentrations less than 2.5 ng/ml; 11 patients (group 2) had a preoperative CEA value above but a postoperative value below 2.5 ng/ml; and 11 patients (group 3) had preoperative and postoperative concentrations greater than 2.5 ng/ml. Cumulative rates of recurrence at 6, 12 and 18 months after operation were as follows: 0, 3 and 17% in group 1; 0, 9 and 21% in group 2; and 27, 79 and 79% in group 3. Statistically there was no difference in the recurrence rate between groups 1 and 2, but the rate was significantly lower in group 2 compared with group 3. The data show that patients in whom the immediate postoperative CEA concentration returns to normal have a much lower incidence of recurrent cancer of the colon than patients whose CEA concentration remains elevated.

Carcinoembryonic Antigen↗
PubMed1977

Management of perforating diverticulitis of the colon.

A retrospective study was carried out of all patients admitted to the hospital with either local or free perforating diverticulitis. Fifty-one patients had perforating diverticulitis of the sigmoid colon with local abscess formation, while 26 patients had free perforation with generalized peritonitis. Of the 67 patients who had a defunctioning colostomy, 18 died, while of ten patients who had either resection or exteriorization of the perforated segment, one died. Thus, exteriorization or resection as the primary surgical procedure for perforating diverticulitis is the procedure of choice, since it leads to a low operative mortality because of removal of the septic focus, preventing continuing intraperitoneal soilage.

Colostomy↗
PubMed1977

The delayed hypersensitivity response: application in clinical surgery.

Delayed hypersensitivity skin testing was performed on 520 surgical patients. Significantly higher incidences of sepsis and mortality (p less than 0.001) were found in the abnormal patients as compared to normal responders in the preoperative (322 patients), postoperative and post-trauma (115 patients), and nonoperative (83 patients) groups. Sequential testing in individual patients was of even greater prognostic value. Of the 177 patients who either remained normal or whose responses became normal, the sepsis rate was 10.1%, and the mortality rate was 8.4%. However, a sepsis rate of 57.6% and a 78% mortality rate were found in those patients who developed abnormal responses or whose responses did not improve. Cancer and increased age (older than 80 years) did not account for the incidence of anergy and relative anergy. The mortality rate was higher in the cancer group. Anergy and relative anergy were found to be associated with malnutrition, sepsis, shock, and trauma. In the clinical setting, effective treatment of these associated conditions, especially the maintenance of body cell mass by the use of total parenteral nutrition, was associated with reversal of the anergic state and an improved prognosis.

Adolescent↗
PubMed1977

Lack of association between breast cancer and HLA (A and B) specificities: importance of age-matched controls.

HLA (A and B) antigen frequencies in 100 women with breast cancer were compared with those in 2 groups of cancer-free control women: the first control group (263 subjects) were age-unmatched, and the second (75 subjects) age-matched. The mean age and standard deviation were 56 +/- 13 years for the patient group, 25 +/- 3 years for the first control group, and 53 +/- 10 years for the second. It was first noted that HLA-B13 was significantly less prevalent among the patients with breast cancer when compared to the first control group (1% versus 7.2%, p = 0.025). However, when the patient group was compared to the second control group, no difference was found in the frequency of HLA-B13 (1% versus 1.3%, p = 0.80) or any other antigens. Age can be an important variable in a study of correlation between HLA and disease.

Adult↗
PubMed1976

Living with the dying: use of the technique of participant observation.

Through participant observation, questions concerning optimal care of dying patients and needs of their families were answered. A general surgical ward and a palliative care unit were the sites of observation. The observations support the belief that a palliative care unit, specifically designed to meet the known needs of dying patients and their families, is preferable to a general surgical ward. The main findings, of less concern in the palliative care unit than on the surgical ward, were the following: the importance of patient-to-patient support; the discomfort of sick-role behaviour; the impersonal and sometimes intimidating nature of patient care; the limitation of the patient's need (as a person) to give as well as to receive; and the value of families, student nurses and volunteers in total care. These findings emphasize the importance of personal interest in relieving the distress suffered by many terminally ill patients.

Anxiety↗
PubMed1976

Comparison of effect of narcotic and epidural analgesia on postoperative respiratory function.

A prospective, randomized comparison was made of the value of meperidine versus epidural analgesia when used for the relief of pain after cholecystectomy in twenty patients without cardiopulmonary disease. Respiratory function was assessed the day before surgery and at 3 to 4 hours and 24 hours after operation by the bedside measurement of expiratory peak flow, vital capacity, and arterial blood gases. The two groups of patients were comparable as to age, height, weight, smoking habits, preoperative peak flow, vital capacity, and duration of operation. The arterial oxygen tension and oxygen saturation were significantly greater and carbon dioxide tension lower in the epidural analgesia group 24 hours after operation. At this time peak flow rates and vital capacity were not different. However, at 3 to 4 hours postoperatively, vital capacity was significantly greater in the epidural anesthesia group. This might account for the differences in arterial blood gases the following day. These findings suggest that epidural analgesia is valuable in the early postoperative period after upper abdominal surgery.

Adult↗
PubMed1976

Alterations in body composition following intestinal bypass for morbid obesity.

The efficacy of the jejunolieal bypass operation, performed as a weight-reducing procedure in the morbidly obese patient, was assessed by measurements of body composition. In 20 patients measurements were performed by multiple isotope dilution, before and following jejunoileal bypass. Prior to bypass the excess body weight was due primarily to an increase in body fat (BF), which accounted for 52 percent of body weight. The nonfatty component of body composition, the lean body mass, although slightly increased in size, was essentially normal. Two distinct patterns were observed following bypass. In 12 patients followed for 8.4 +/- 1.5 months, there was a 21 percent decrease in body weight, resulting entirely from a loss of BF. The total exchangeable potassium and intracellular water volume, both measures of the body cell mass (BCM), were unchanged. In the second group of eight patients followed for 13.9 +/- 2.1 months, the mean body weight decreased by 27 percent or 38.8 Kg., due to a 26.6 Kg. reduction in BF and a 13.0 Kg. decrease in the BDM. This was accompanied by a relative expansion of the extracellular mass. As a result, the mean Nae/Ke ratio increased significantly (p less than 0.05) from a normal prebypass value of 0.95 +/- 0.7 to 1.46 +/- 0.11 following bypass. Thus in eight of the 20 patients following jejunoileal bypass, there was an undesirable loss of BCM with a relative expansion of extracellular supporting component of body composition, a pattern characteristic of malnutrition.

Adult↗