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Biomedical subjects

G T Shires

Publications and source records attributed to G T Shires.

At least 127 records · Page 7Linked to original sources
PubMed1982

Red blood cell sodium content and permeability changes in hemorrhagic shock.

Recent studies of cellular function have demonstrated significant alterations of cell homeostasis during hemorrhagic shock. The progressive depolarization of cell membranes demonstrated in several organs has been attributed to failure of energy-dependent active ion transport. Similar changes in intracellular electrolyte composition have been observed in the red blood cells of some patients in late hemorrhagic shock and in other severely ill patients. The ready availability of isolated cells that do not require extracellular fluid space assessment makes the red blood cell an attractive model for investigating the factors controlling ion movements across the cell wall. It has been suggested that the red blood cell ion abnormalities may represent a generalized cellular response to severe illness. Red blood cell sodium concentration was measured in 145 patients during severe hemorrhagic shock. The direction and magnitude of changes in red blood sodium concentration was correlated with the time course of the shock state. The initial decrease in sodium content was a function of the diminished red blood cell membrane permeability due to a decrease in plasma bicarbonate levels. The subsequent red blood cell sodium uptake above the normal range, not associated with an increase in sodium influx, indicated an impairment of energy-dependent active transport. The observed high sodium concentrations associated with a potassium decrease in the red blood cell appeared to be only one manifestation of a generalized defect in cellular function and composition during severe hemorrhagic shock.

Biological Transport, Active↗
PubMed1982

Pancreaticoduodenectomy. A 40-year experience.

One hundred six pancreaticoduodenectomies, including 10 cases done for benign disease were reviewed, retrospectively, and 51 factors analyzed. There is a significant difference in survival based upon final pathologic diagnosis. Five-year survivals were 0% for adenocarcinoma of the pancreas, 38% for duodenal carcinoma, 24% for CBD caracinoma, 30% for ampullary carcinoma, 24% for other cancers not considered part of the ampullary carcinoma, 24% for other cancers not considered part of the ampullary region, and 100% for those with benign disease (chi 2 = 24.66, df = 5, p = 0.0002). Four statistically significant poor prognostic factors were identified, including age greater than 51 years, serum bilirubin level greater than 6 mg/dl, SGOT greater than 100, and a previous drainage procedure. Results of this study seem to indicate that the pancreaticoduodenectomy has limited indications in adenocarcinoma of the pancreas, but remains the procedure of choice for all other periampullary lesions including suspicious lesions with a negative biopsy at the time of surgery.

Adolescent↗
PubMed1982

The effect of intravenous steroids on alveolar-capillary membrane permeability in pulmonary acid injury.

The treatment of pulmonary aspiration of gastric contents remains largely empirical. The purpose of the present study was to evaluate the effect of methylprednisolone administration (30 mg/kg) on alveolar-capillary membrane permeability after pulmonary acid aspiration in dogs. Alveolar-capillary membrane permeability was assessed by several methods. Extravascular lung water volume (EVLW), extravasation of 125I-serum albumin (RISA) into lung parenchyma, and albumin leak into the alveolar spaces were measured. EVLW increased progressively from 5.5 +/- 0.6 to 20.0 +/- 2.3 ml/kg in Group I (Acid) and from 5.4 +/- 1.2 to 22.1 +/- 3.1 ml/kg in Group II (Acid + Steroids) over the 5 hours after acid injury. The ratio of Lung Extravascular RISA to Plasma RISA was 0.56 +/- 0.14 and 0.58 +/- 0.14 in Group I and Group II, respectively (normal = 0.19 +/- 0.06). The tracheal albumin to plasma albumin ratio remained near 1.0 from 2 hours to 5 hours post-aspiration in both groups. This study demonstrated that pulmonary acid injury resulted in a marked increase in alveolar-capillary permeability to albumin, smaller solutes, and water which was not ameliorated by the administration of methylprednisolone.

Adrenal Cortex Hormones↗
PubMed1982

Changes in sodium, potassium, and adenosine triphosphate contents of red blood cells in sepsis and septic shock.

Sepsis and septic shock were induced in fifteen awake rabbits by the infusion of live Escherichia coli. Sodium K+, and adenosine triphosphate (ATP) concentrations in red blood cells (RBC) and plasma were measured during the control, septic, and septic shock periods. The significant elevations of Na+ content in RBC during sepsis appeared to be primarily a function of increased cell membrane permeability. The significantly decreased intracellular K+ concentrations, accompanying the high Na+ levels of RBC later in shock, were consistent with progressive failure of the energy-dependent transport mechanism (Na+-k+ pump). Hyponatremia and hyperkalemia were apparent in the late stages of sepsis, these alterations reached statistically significant levels in the shock period. The electrolyte derangements associated with sepsis and septic shock could not be related to energy depletion. The continuous significant accumulations of ATP, observed in RBC and plasma, were interpreted as a result of decreased energy utilization and attributed to the diminished active ion transport by the impaired Na+-K+ pump.

Adenosine Triphosphate↗
PubMed1982

Effects of naloxone in hemorrhagic shock.

The endorphins appear to play an integral role in the physiopathology of hemorrhagic shock. Blockade of these endodgenous opiates by naloxone can significantly alter the course of this syndrome. While the administration of naloxone to normal rats had no effect upon the circulation or cellular function, it improved the hemodynamic status of rats subjected to hemorrhagic shock, resulting in improved tissue perfusion. In addition, the administration of this drug prevented the cellular dysfunction normally seen in hemorrhagic shock. This effect was independent of its salutary effects upon the circulation.

Animals↗
PubMed1981

Membrane defect and energy status of rabbit skeletal muscle cells in sepsis and septic shock.

Measurements of the resting membrane potential in skeletal muscle were used to monitor cell function in live Escherichia coli-induced sepsis and septic shock. Depolarization of the cell membrane, indicative of cell swelling, occurred before the onset of deep hypotension, suggesting cellular injury as a primary cause rather than a result of shock. The normal values for high-energy phosphates found in skeletal muscle in the terminal stages of shock reduce the possibility of an energy deficit as one of the factors in the cellular membrane malfunctions in septic shock.

Animals↗
PubMed1981

The effect of increasing end-expiratory pressure on extravascular lung water.

The objective of this study was to define the response of extravascular lung water (EVLW) to different levels of positive end-expiratory pressure (PEEP) following a standardized oleic acid injury to the lung. All animals responded to the injection of intravenous oleic acid by the rapid development of hypoxemia. There was a twofold increase in EVLW during the first 3 hours after oleic acid injection which remained stable during the remainder of the experiment, including periods on PEEP. Intrapulmonary shunt (Qs/Qt) increased significantly (P less than 0.001) during the first hour following oleic acid injection. PEEP therapy resulted in an immediate decrease in Qs/Qt and amelioration of the hypoxemia. Return to zero PEEP resulted in a rapid decrease in PaO2 with concomitant increase in Qs/Qt by the end of the experiment. The oxygen transport in the animals did not improve significantly with the addition of PEEP. This was due to the decrease in cardiac output that more than offset the effects of a diminished Qs/Qt with PEEP. This study indicates that the mechanism by which PEEP improves oxygenation does not appear to be mediated by effect on lung water. The study also emphasizes the importance of determining oxygen transport when managing patients on PEEP.

Animals↗
PubMed1981

Measurement of lung water in inhalation injury.

Pulmonary inhalation injury is a major cause of morbidity and mortality rates in burn victims. But the pathophysiology of parenchymal inhalation injury has not been fully elucidated. In this study, extravascular lung water volume (EVLW) was measured in burn patients with and without inhalation injury. Patients with parenchymal inhalation injury (group II) had elevated admission extravascular lung water volumes (10.12 +/- 3.43 ml/kg), whereas patients without parenchymal injury (group I) had significantly lower lung water values (3.91 +/- 1.49 ml/kg). Both accumulation of EVLW and ventilation-perfusion abnormalities in the group II patients occurred within hours of smoke inhalation. But the severity of inhalation injury did not consistently correlate with the elevation of EVLW. This indicated that both interstitial edema and ventilation-perfusion imbalance contributed, in varying degrees, to the pathophysiology of inhalation injury. In this study, the general clinical criteria for inhalation injury--presence of facial or oropharyngeal burns, carboxyhemoglobin levels, carbonaceous sputum, or closed space injury--did not differentiate patients with airway injury only from those with parenchymal injury. Patients in both groups who died of sepsis had significant (P less than 0.01) increases in EVLW 24 to 48 hours after the clinical onset of sepsis. The normal hydrostatic pressures in these septic patients suggested that the increase in EVLW observed with sepsis was due to an increase in pulmonary capillary membrane permeability.

Adult↗
PubMed1980

Transplantation of the cryopreserved nipple-areolar complex.

The full nipple-areolar complex of dogs has been successfully removed, cryopreserved using a controlled-rate freeze protocol, and reimplanted without loss of viability. The technique for reimplantation calls for the use of a new fixed double bolus technique that prevented dislodging or contamination in all but 2 cases. The feasibility of performing this procedure in humans is discussed.

Animals↗
PubMed1980

Burn injury. Analysis of survival and hospitalization time for 937 patients.

The charts of 937 patients have been reviewed for survival and length of stay. Probit analysis and binary logistic regression has been performed to develop probability of dying contours incorporating age and per cent burn. It appears that improvement in survival has occurred over the last 16 years. The length of hospital stay has also been evaluated. A significant decrease in hospitalization time has occurred in the past year with the advent of a selective wound excisional protocol, without adversely affecting survival. A burn bed requirement chart is presented which incorporates age, burn size, survival probability and predicted length of stay. The chart allows for estimation of burn bed needs for a known or predicted population of regional burn victims.

Adolescent↗
PubMed1980

The effect of hemorrhagic shock on potassium transport in skeletal muscle.

The ion exchanger potassium microelectrode was used to assess the potassium concentration in the interstitial fluid of skeletal muscle in the control and shock states. Concomitant resting membrane potential measurements and the analysis of fluid and electrolyte content of biopsies of the muscle were used to detect defects in cellular function. The changes occurring in hemorrhagic shock were consistent with a depression of resting transmembrane potential, depletion of extracellular fluid and cellular swelling with sodium uptake and potassium loss. The disproportional increase of interstitial potassium concentration over that of the plasma in low flow states appeared to be a result of inhibited sodium-potassium transport in cell membranes, concomitant with an equilibration delay between these two extracellular compartments. The significant increase in potassium concentration in the interstitium may have potentiated other changes in cardiovascular and respiratory functions which have been observed in the complex picture of hemorrhagic shock.

Animals↗
PubMed1979

Surgical management of traumatic injuries of the right colon. Twenty years of civilian experience.

Three hundred seven patients with right colon injuries were treated at Parkland Memorial Hospital, Dallas, between 1953 and 1973. These injuries were managed with loop colostomies, suture and cecostomy, primary repair, right colectomy, diverting colostomy, and appendectomy or cecostomy alone. The indications and results of each type of repair are analyzed separately. The mortality (3.21%), morbidity (22%), and hospital stay were not related to the modality of treatment, but were influenced by the injuring agent. Adequate treatment of civilian right colon injuries implies careful individualization to avoid serious septic complications and subsequent mortality.

Adult↗