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Biomedical subjects

B Coleman

Publications and source records attributed to B Coleman.

At least 55 records · Page 3Linked to original sources
PubMed1984

CT imaging of the unusually shaped bladder.

In the CT evaluation of a cystic pelvic mass it is important to identify the urinary bladder and assess its relationship to the mass. Although this is generally an easy task, we have encountered cases where delayed opacification of the bladder created diagnostic difficulties. Following intravenous contrast medium infusion, patients with normal renal function may have unopacified bladders due to (a) delayed transit from kidney to bladder and (b) rapid CT imaging of the bladder before opacification can occur. If one is aware of these problems, diagnostic dilemmas may be reduced by obtaining delayed scans of the pelvis or by obtaining postvoid films. Two cases are presented to illustrate these points.

Aged↗
PubMed1984

Increased lipid fuel dependence in the critically ill septic patient.

The effect of sepsis in modifying post-surgical fuel utilization in critically ill patients was determined from 374 observations (246 septic [S] and 128 nonseptic [N] in 12 intubated ICU patients studied serially. Patients received TPN (values/24 hrs: Septic, N2, 9.1 +/- 2.2 gm; glucose, 543 +/- 211 kcal/m2, Nonseptic, N2, 8.3 +/- 3.6 gm; glucose, 550 +/- 346 kcal/m2). In some periods, intravenous lipid (L) was given to raise total caloric intake to 826 +/- 223 kcal/ 24 hr/m2. The VO2, VCO2, respiratory rate, minute volume, and blood gas levels were measured, and respiratory quotient (RQ) and metabolic rate (MR) computed. Statistics were performed by 2-way ANOVA and analysis of covariance. Without lipid, mean VCO2 for S (126 ml/min/m2) and N (128 ml/min/m2) were not significantly different, but VO2 in S (146 ml/min/m2) and N (132 ml/min/m2), and the RQ values S (0.88) and N (0.97), were different (p less than 0.0001). In 360 studies RQ was shown to be increased by the total caloric intake, but reduced in the presence of sepsis: RQ = 0.00014 (kcal/m2) - 0.09 (sepsis effect + 0.878 N = 360; r2 = 0.304; F2,357 = 78; p less than 0.0001; but both administered glucose and lipid calories contribute to the RQ in sepsis: RQ = 0.00017 (glucose kcal/m2) + 0.266 X 10(-3) (lipid kcal/m2) + 0.732 n = 114; r2 = 0.260; F2,111 = 19.5; p 0.0001. Sepsis increased VO2 with little change in VCO2, thus RQ fell, suggesting increased use of lipid fuels for oxidation. During hypercaloric lipid infusion in septic patients (SL) VO2 and VCO2 increased but VO2 was still greater, so RQ remained low (SL RQ = 0.89). As sepsis worsened VO2 remained high but VCO2 fell producing RQ less than 0.8, while plasma glucose levels were increased. These data suggest that septic patients are more dependent than nonseptics on lipid fuels for oxidative metabolism, and that IV lipids can be used to increase oxidative metabolism in sepsis at a time when glucose metabolism appears reduced.

Aged↗
PubMed1982

Pathologic synergy in cardiovascular and respiratory compensation with cirrhosis and sepsis. A manifestation of a common metabolic defect?

Multivariable physiologic studies of cardiovascular, respiratory, and metabolic functions were performed in 341 patients (884 studies). Eighty patients had cirrhotic liver disease, 64 had sepsis, 87 had nonseptic cariogenic syndromes, and 110 had nonseptic general surgical or traumatic injury. The group with cirrhosis had the highest cardiac index and ejection fraction. When compared with the group with nonseptic surgery or trauma, vascular tone was reduced in the patients with cirrhosis or sepsis and was lowest in patients with both conditions. Ventricular function was good in the groups with cirrhosis or sepsis, due to the additive effect in reducing vascular tone that allowed ejection fraction to increase, but caused the ratio of alveolar ventilation to perfusion (VA/QT) to fall, resulting in a greater perfusion of a decreased pulmonary vascular bed. The falls in vascular tone and VA/QT in patients with cirrhosis or sepsis result from the reduced oxygen consumption that occurs due to metabolic imbalance (B state). This B state seems to reflect a hepatic inability to metabolize aromatic amino acids, so that levels of tyrosine, phenylalanine, and the false neurotransmitter octopamine increase. These mechanisms are pathologically synergistic when sepsis and cirrhosis occur together.

Amino Acids↗
PubMed1982

Effect of valium (diazepam) on experimental atherosclerosis in roosters.

The development of aortic and coronary atherosclerotic plaques were investigated in roosters fed an atherogenic diet with and without the addition of Valium (0.2 mg/kg twice daily) over a period of 5 months, as a step toward understanding the role of emotional factors in atherogenesis. Plasma levels of cholesterol and triglycerides, hemodynamic parameters, and body weight were measured. There was a progressive, and quantitatively similar, body weight gain in all birds. In addition, there were no significant differences in values for blood pressure, cardiac output, and heart rate between the various experimental groups. Conversely, birds receiving the atherogenic diet, as well as those receiving the atherogenic diet along with Valium, exhibited a marked hypercholesterolemia which reached a peak of 600 mg/dl in 4-6 weeks, before decreasing to between 200 and 300 mg/dl by the 10th week. Plasma triglyceride levels followed a qualitatively similar pattern as plasma cholesterol. Those birds fed an atherogenic diet alone developed atherosclerotic lesions on the aortic surface which was more pronounced on the abdominal than the thoracic aorta. Aortas from birds given Valium along with the atherogenic diet were completely free of lesions despite the fact that plasma cholesterol and triglyceride levels were not significantly different in the two groups. Histological sections of coronary arteries showed severe lesions in 4 out of 7 birds which were fed the atherogenic diet alone, whereas the birds given Valium along with the atherogenic diet had only an occasional slight lipid deposit. It was concluded that Valium provides some protection against the development of atherosclerosis in roosters fed an atherogenic diet.

Animals↗
PubMed1981

Death after portal decompressive surgery. Physiologic state, metabolic adequacy, and the sequence of development of the physiologic determinants of survival.

Detailed serial cardiovascular and respiratory physiologic studies were carried out in 80 patients with cirrhotic liver disease, including 45 cirrhotic patients who underwent portal decompressive surgery on an urgent or elective basis. In surgical cases, death could be predicted from the first postoperative day's pattern of response. Predictors of death were an increase in percent of pulmonary shunt due to a redistribution of the increased pulmonary blood flow, and a disproportionate fall in vascular tone, which permits an increased cardiac ejection fraction even when significant myocardial depression occurs. The etiology of the vascular tone defect seems related to the rise in levels of the false neurotransmitter octopamine, which are shown to increase as oxygen consumption falls in the patho-physiologic hyperdynamic B state, presumably due to a block in the oxidative metabolism of aromatic amino acids.

Esophageal and Gastric Varices↗
PubMed1981

Percutaneous nephrostomy: comparison of sonographic and fluoroscopic guidance.

Both sonography and fluoroscopy have been recommended for renal localization and needle guidance for percutaneous nephrostomy. The respective efficacies of both methods have been compared in a prospective study of 88 patients undergoing percutaneous nephrostomy by the catheter over guide wire technique. Fifty-five patients had initial puncture using either an A-mode (42 patients) or real time (13 patients) sonographic aspiration transducer, while 33 patients had a single plane vertical beam fluoroscopy for puncture guidance. The use of either sonographic method for the initial needle puncture significantly reduced the number of puncture attempts (p = 0.000004) and potential iatrogenic risk, eliminated the need for intravenous administration of contrast material, allowed initial safe introduction of a large caliber needle, and decreased the length of time needed to perform the procedure.

Drainage↗
PubMed1980

Septic autocannibalism. A failure of exogenous nutritional support.

Forty-six patients with surgical sepsis were studied prospectively until death or survival to evaluate the effect of exogenous metabolic support on the observed plasma substrate levels and on the differential endogenous utilization of branch chain amino acids. There were no effects of administered glucose or colloid load. The administered amino acid load had little effect on substrate levels in patients who died; but significantly effected the observed levels of glycine, isoleucine, and methionine in patients who survived. Evidence is presented which suggests that fatal sepsis is associated with an increased release of endogenous valine and isoleucine into plasma, as well as increased plasma levels of tyrosine, proline, and methionine. These abnormalities are highly correlated with the increased levels of plasma alanine and occur at a time when the nonsurviving septic patient manifests a tendency toward reduced oxygen consumption and abnormal vascular tone relations--the septic B state. These data are consistent with the hypothesis that increased muscle protein catabolism is occurring with a differential utilization of branch chain amino acids and increased use of leucine and isoleucine and reduced use of valine. This autocannibalism of muscle mass appears to be the source of the increased plasma alanine and is little influenced by administered amino acid support in the absence of control of the septic process.

Alanine↗
PubMed1979

Physiological and metabolic correlations in human sepsis. Invited commentary.

The septic response in man appears to be a disease in which the infecting agent induces a state of disordered metabolic control in the host. The abnormal regulation of metabolic pathways causes a diversion of substrate utilization toward gluconeogenesis and ketone body formation and a reduction in oxidative energy-producing metabolism. This state of metabolic insufficiency is reflected in the pattern of cardiorespiratory, vascular, and physiological compensation. The precise magnitude of the resultant physiological compensation and its rate and direction of change can be quantified by the use of physiological state trajectories which also reflect the magnitude of underlying metabolic derrangements. The prognostic and therapeutic implications of these changes are discussed.

Amino Acids↗
PubMed1979

Ventilation:perfusion maldistribution secondary to the hyperdynamic cardiovascular state as the major cause of increased pulmonary shunting in human sepsis.

Cardiovascular and respiratory parameters were obtained in 374 studies from 151 patients (64 septic or septic shock and 87 with nonseptic cardiogenic syndromes). Cardiac output and related measures, respiratory parameters, pulmonary blood volume (DV/m2), cardiac ejection fraction (EFx), left ventricular end-diastolic volume (LVEDV), peripheral resistance (TPR), pulmonary shunt (QS/QT), physiologic dead space (VD/VT) and mean ventilation perfusion ratios (VA/QT) were calculated. Both physiologic evaluation and multivariable statistical analyses of the data were performed. For a given level of (A-aO2 gradient/PaO2) septic patients have a higher QS/QT than cardiogenic patients. Hyperdynamic septic patients have a larger QS/QT, a greater VD/VT, and a lower VA/QT and TPR than cardiogenics. The decrease in VA/QT and the rise in VD/VT are strong functions of the increased EFx, which raises cardiac index (CI) and reduces LVEDV and the mean dispersion of pulmonary blood volume, thus causing hemodynamic redistribution of flow. QS/QT is mainly a direct function of the increase in CI which also tends to reverse the EFx-mediated rise in VD/VT. The role of the septic mediated decrease in TPR as a contributing pathologic feature and the use of volume infusion to raise LVEDV and VA/QT in high-CI septics with large QS/QT is discussed.

Blood Circulation↗
PubMed1977

Effects of alpha-adrenergic blockade on renal function in hemorrhagic shock.

This study was undertaken to determine whether alpha-adrenergic blockade would reverse the altered kidney function in hemorrhagic shock. Urinary excretion of Na+, K+, and total solute were studied in 10 anesthetized dogs before and after administration of phenoxybenzamine (PBZ) in shock. Five of the 10 dogs were used to evaluate the effect of shock on renal hemodynamics. Another group of five dogs was used as controls. Normovolemic shock caused a reduction in renal blood flow (RBF) from 9.0 +/- 1 to 6.0 +/- 0.6 ml/min per kg, and an increase in renal vascular resistance (RVR) (P less than .05). When compared to the untreated shock animals, phenoxybenzamine caused an 83% increase in RBF and a 53% decrease in RVR. Treatment of control animals with phenoxybenzamine resulted in a 10-fold increase in urinary [Na+], while urinary [K+] remained unchanged. Neither urinary [K+] nor urinary [Na+] was affected significantly by PBZ in the shock group. Although the excretion rate for Na+ was increased severalfold in the untreated shocked animals when compared to controls (14.0 +/- 3 vs. 1.7 microneq/min) the excretion rates for K+ (P less than .05) and total osmotically active substances (P less than .01) diminished. Phenoxybenzamine caused significant increases in the excretion rates for Na+ and K+ in both the control and shocked dogs. The observed changes in excretion rates when PBZ was given most likely reflect drug-induced changes in renal hemodynamics.

Animals↗
PubMed1977

On the function of the aortic valve and the mechanism of the first and second sounds.

Studies are reported on the exact timing of the aortic component of the second sound in relationship to aortic pressure and flow velocity, and also to aortic valve closure. These studies were performed in animals by means of catheter-tip probes and an electric contact introduced into the aortic valve. They were supplemented by echocardiographic stuides of the aortic valve, and impedance cardiograms in man. Opening of the aortic valve and its relationship to the first heart sound were also studied. It was observed that the second component of the first heart sound grossly coincides with the opening of the aortic valve. The aortic component of the second sound starts a few milliseconds after aortic valve closure. It starts after the incisura of the aortic pressure tracing and the drop of the velocity curve to the zero line; it then increases attaining its maximum at the peak of the rapid rebound of the aortic pressure, which coincides with the trough of the velocity tracing. The final interpretation on the mechanism of the second sound agrees in principle with the studies of Luciani, Wiggers, and Rushmer attributing the sound vibrations to release of the energy stored in the aortic wall, which accelerates the flow and causes deceleration of numerous structures (aortic and valvar) as well as of the blood. Studies of the rate of change of acceleration of pressure confirm this interpretation.

Adolescent↗
PubMed1976

Sympathetic influence on ventricular compliance.

Intracisternal injections of veratrine in the anesthetized dog were used to study the effects of extreme sympathetic stimulation on left ventricular diastolic compliance. The results obtained were compared with those seen during volume expansion with whole blood, and after removal of both stellate ganglia. The injection of veratrine into the cisterna magna caused an increase in left ventricular end-diastolic pressure (LVEDP) which was considerably larger than that which occurred in left ventricular end-diastolic circumferential (LVEDC) segment length suggesting a reduction in diastolic compliance. There were also increases in left ventricular systolic pressure (LVSP) as well as its first derivative (LV dp/dt). Bilateral stellectomy during the veratrine response abruptly reduced LVEDP with a lesser decrease in LVEDC. Thus, the left ventricular compliance change was reversed. Both LVSP and LV dp/dt were decreased by stellectomy but remained above control levels. During transfusion, the pressure-length curve of the ventricle was located downward and to the right in comparison with the curve observed with intracisternal veratrine.

Animals↗
PubMed1975

Myocardial performance during hemorrhagic shock in the pancreatectomized dog.

Myocardial performance was evaluated in nine pancreatectomized and 12 nonpancreatectomized dogs by measuring left ventricular pressure (LVP), maximal dP/dt (max dP/dt), left ventricular end-diastolic pressure (LVEDP), pulmonary arterial pressure (PAP), aortic pressure (AoP), and lead II of the electrocardiogram during standardized hemorrhagic shock. Cardiac output (CO) and hematocrit were determined before hemorrhage, after 4 h of oligemia, when postinfusion mean blood pressure declined to 60 mmHg. Left ventricular function curves were obtained, by varying preload, in control dogs and 2 h after reinfusion of the shed blood in those dogs subjected to shock. Both groups of dogs showed identical responses to the shock procedure. In the immediate postinfusion period, LVP, max dP/dt, LVEDP, and mean blood pressure returned to near-control values, while PAP was significantly elevated. The postinfusion decline (after 60-90 min) in AoP was accompanied by a similar reduction in LVEDP. Left ventricular performance in hemorrhagic shock did not differ significantly from that seen in control dogs. In addition, there was no electrocardiographic indication of myocardial ischemia. The data indicate that terminal hemorrhagic shock need not be accompanied by myocardial depression whether or not the pancreas is intact.

Animals↗
PubMed1975

Prediction of body density in young and middle-aged women.

The purpose of this investigation was to predict body density of young and middle-aged women and to determine if the use of a greater variety of variables, particularly those for fat in the bust and hip regions, increases the predictability of body density. Body density determined by the hydrostatic technique (dependent variable) was obtained from 83 volunteer young women and 60 middle-aged women ranging from 18 to 22 and 33 to 50 yr of age, respectively. Independent variables included 8 skinfold, 13 girth, and 7 diameter measures; age; height; weight; and bra and cup sizes. Mean body density for young women was 1.043 g/ml (SD plus or minus 0.014) and percent fat, 24.8 (SD plus or minus 6.4); 1.031 g/ml (SD plus or minus 0.015) and 29.8% (SD plus or minus 6.7) for middle aged subjects. Percent fat was calculated by the formula of Siri. Factor analysis was used to examine the dimensions measured by the independent variables as a function of age. A multiple regression model was used to develop predictions of body density from the independent variables. The best combination of four variables for predicting body density was skinfold thigh, skinfold suprailiac, cup size, skinfold suprailiac, girth waist, and skinfold thigh (R = 0.89) for middle-aged women. The data showed that the highest predictons were found by using combinations of skinfold, girth, and diameter variables; cup size also supported the need for different regression equations for different age groups.

Adolescent↗