Biomedical subjects

P B Alden

Publications and source records attributed to P B Alden.

6 recordsLinked to original sources

PubMed1990

Sepsis-induced diastolic dysfunction in chronic canine peritonitis.

A chronic canine model of hyperdynamic sepsis was achieved by cecal ligation and puncture (SEP) in conjunction with continuous high-volume fluid resuscitation. Cardiac function was evaluated using ultrasonic cardiac crystals placed across the major, minor, and wall thickness axes of the left ventricle, together with simultaneous arterial and ventricular pressure measurement. Seven to 10 days after crystal implantation, animals were randomized to either SEP (n = 10) or sham laparotomy control (n = 7). SEP dogs became febrile and lethargic, with elevated leukocyte counts and positive blood cultures for enteric organisms. They were also hyperdynamic, with significant increases in heart rate and cardiac output and a fall in systemic vascular resistance. Systolic blood pressure, stroke volume, and ejection fraction remained stable. Relative to control, the SEP group demonstrated a significant reduction in intrinsic contractility during systole, as measured by the heart rate and load-independent index of left ventricular performance Emax (P less than 0.01), confirming the observations of others. In addition, however, diastolic function also became markedly abnormal with a progressive increase in unstressed and end-diastolic ventricular volumes (P less than 0.05) and a significant decrease in myocardial compliance as quantitated by transmural pressure vs. volume-strain analysis. It is hypothesized that this increase in diastolic volume helps to maintain global cardiac performance during the hyperdynamic response to sepsis in the presence of adequate volume support.

Animals↗

PubMed1989

Volvulus of the gallbladder. Report of two cases and review of the literature.

Torsion or volvulus of the gallbladder is a rare cause of acute cholecystitis. Although it has been reported in all age groups, it is most commonly seen in the elderly. With our increasingly aged population, it behooves the clinician to keep this entity in mind when treating the older patient with abdominal pain. We present two cases of torsion of the gallbladder and review the clinical and pathological aspects of this disease.

Acute Disease↗

PubMed1987

Essential fatty acid status in isolated closed head injury.

Abnormal profiles of polyunsaturated fatty acids in the plasma phospholipid fraction were observed in 14 patients with hypermetabolism due to severe isolated closed head injury. Depressed linoleic acid levels were observed within 24 hours along with elevation of oleic acid levels. By one week postinjury, subnormal levels of arachidonic acid were also observed. These data indicate that the metabolic response to injury encompasses changes in the metabolism of polyunsaturated fatty acids which are rapid in onset and qualitatively similar to those seen in mild essential fatty acid deficiency.

Adult↗

PubMed1987

Left ventricular function in malnutrition.

Twenty-one dogs were chronically instrumented with ultrasonic left ventricular dimension transducers and micromanometers to elucidate the effects of acute protein-calorie malnutrition on cardiac function. Ten dogs received a regular diet for 3 wk, whereas 11 dogs received a protein-calorie-deficient diet designed to achieve a mean weight loss of 20-25% over a 3-wk period. Studies of cardiac function were performed in awake intact animals at base line (1 wk postoperatively) and after 3 wk. In the malnourished dogs, cardiac mass was lost in proportion to total body mass loss. Mean cardiac mass fell from 115 to 91 g. This was largely due to wall thinning in this group. Heart rate dropped from 125 to 79 beats/min with malnutrition and ejection fraction increased from 29.8 to 34.6%. Cardiac output fell from 2.98 to 2.38 l/min, but cardiac index normalized to body surface area was unchanged. No significant changes in hemodynamics were observed in the control group. In the malnutrition group, global ventricular contractility, as measured by the load-independent index of systolic function or the slope of linear relationship between end-systolic pressure and end-systolic volume (EmaxPV), decreased slightly from 3.56 to 2.81 mmHg/ml (P = 0.07). However, Emax calculated from circumferential stress and strain data was unchanged. This indicates that depressed contractility was due to loss of cardiac muscle mass rather than any change in the myocardium per se. Response to beta-adrenergic stimulation was unchanged with starvation. Acute protein-calorie malnutrition causes significant cardiac atrophy that is reflected in decreased cardiac output and slightly reduced contractility but not in intrinsic properties of the myocardium.

Animals↗

PubMed1986

Partial correction by exogenous lipid of abnormal patterns of polyunsaturated fatty acids in plasma phospholipids of stressed and septic surgical patients.

Polyunsaturated fatty acid (PUFA) profiles are abnormal in a variety of clinical conditions that are commonly seen in the surgical intensive care unit. PUFA profiles in the serum phospholipids were studied by capillary gas chromatography in 22 critically ill, hypermetabolic surgical intensive care unit patients. All patients received continuous total parenteral nutrition (TPN) by central vein with trace elements and vitamins. Eleven patients received daily supplementation with 50 gm of safflower oil-based lipid emulsion (TPN + L group). No lipid was administered in the other 11 patients (TPN). Both groups showed deficiencies in 18:2 omega 6 linoleic acid from the time of onset of TPN. In TPN the deficiency was progressive; in the TPN + L group, lipid administration prevented this progression but did not restore 18:2 omega 6 levels to normal. In the TPN group levels of 18:1 omega 9 and its metabolite 20:3 omega 9 (the triene of deficiency) increased over time, consistent with a mild essential fatty acid deficiency. These changes in omega 9 acids were not seen with lipid supplementation. Despite low levels of 18:2 omega 6 in both groups, the levels of omega 6 metabolites were normal or increased. Levels of 20:4 omega 6 (arachidonate) remained normal or slightly decreased in the TPN group but were decreased in the TPN + L group. Levels of arachidonate metabolites, in particular 22:5 omega 6, were increased in the lipid-supplemented group. We concluded that stressed patients receiving TPN develop mild essential fatty acid deficiency that is only partially correctable by lipid supplementation and that administration of supplemental lipid to these patients stimulates arachidonic acid conversion to 22:5 omega 6.

Aged↗

PubMedDate not supplied

Cardiac beta-adrenergic responsiveness is well preserved in moderate protein calorie malnutrition from semistarvation.

Twenty-one dogs underwent instrumentation of the left ventricle with ultrasonic dimension to study the effects of acute protein-calorie malnutrition on the adrenergic responsiveness of the heart. This study allowed a chronic and dynamic measurement of the major cardiac axes and the ventricular wall thickness, which in turn can be used to derive sophisticated measurements of global and intrinsic left ventricular function. Of the 21 dogs, 11 received a protein- and calorie-deficient diet designed to achieve a mean weight loss from a baseline of 20-25% over a 4-week period. The other 10 dogs received a normal diet. Dogs were also randomized to receive either acute propranolol beta-receptor blockade (n = 9) or acute isoproterenol beta-receptor stimulation (n = 12) during their baseline studies. Of the nine dogs given propranolol, five were subsequently malnourished and four served as controls. Of the 12 given isoproterenol, six were rendered malnourished and six were controls. All dogs were studied at both baseline and 4 weeks and received drugs in an identical fashion during both studies. The significant changes with malnutrition consisted of decreases in heart rate, cardiac mass, and left ventricular wall thickness. The degree of change in stroke volume, ejection fraction, cardiac output, dp/dt, and Emax (index of left ventricular contractility), with the administration of propranolol or isoproterenol was unaltered by malnutrition. These data support the contention that moderate protein-calorie malnutrition is well tolerated in instrumented, unstessed dogs and that the left ventricle's capacity to respond to beta-stimulation and to tolerate beta-blockade is largely unimpaired.

Animals↗