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Biomedical subjects

D M Shah

Publications and source records attributed to D M Shah.

At least 253 records · Page 14Linked to original sources
PubMed1977

Cardiac output and pulmonary wedge pressure. Use for evaluation of fluid replacement in trauma patients.

Cardiac output and pulmonary wedge pressure (PWP) were used to evaluate the end point of fluid resuscitation in 20 patients suffering from multiple trauma and shock. Eleven patients received crystalloid resuscitation and nine patients received colloid resuscitation. Fifteen of 20 patients had an adequate cardiac output at the termination of resuscitation, but but only six of these patients had a PWP above 10 mm Hg. There was no significant correlation between left ventricular stroke work index and PWP in these patients, either at the completion of resuscitation or during the following three days. Five patients did not achieve adequate cardiac output and four of these patients died, suggesting that cardiac output was the most important criterion for adequate resuscitation. If the goal of fluid resuscitation is to achieve an adequate cardiac output, then PWP was not a reliable guide. Furthermore, using both cardiac output and PWP as a guide to fluid resuscitation of our patients, we found that the type of fluid (crystalloid or colloid) for resuscitation did not influence the course of respiratory distress in these patients up to three days following resuscitation.

Adult↗
PubMed1977

Complex mitochondrial DNA in Drosophila.

The larval mtDNA isolated from D. virilis, D. simulans and D. melanogaster exists in complex molecular forms in addition to the simple monomeric circular form. The frequency of circular dimers and oligomers is highly elevated in apparently normal larval tissues. These complex forms of mtDNA are separable on agarose gels. Hind III restriction endonuclease and electron microscopic analyses used in the present study have revealed that circular dimers are simply the circular concatemers of two monomeric circles which are arranged in a head-to-tail structure with no detectable heterologous regions such as insertions or deletions. The electrophoretic patterns of Hind III digested mtDNAs of D. simulans and D. melanogaster (sibling species) are identical and distinguishable from that of distantly related species, D. virilis.

Animals↗
PubMed1977

Continuous positive airway pressure versus positive end-expiratory pressure in respiratory distress syndrome.

The hemodynamic and respiratory effects of spontaneous ventilation with continuous positive airway pressure (CPAP) and mechanical ventilation with positive end-expiratory pressure (PEEP) were compared in nine patients who had adult respiratory distress syndrome. These patients were capable of maintaining spontaneous ventilation (tidal volume above 300 ml. and PaCO2 below 45 torr). Arterial and mixed venous blood gases, cardiac output, oxygen delivery and consumption, pulmonary artery pressure, and pulmonary wedge pressure were measured in 11 instances, with each patient on 5 or 10 cm. H2O CPAP or PEEP, and in nine instances, with each patient on the ventilator but without PEEP (O PEEP). During CPAP, when compared to PEEP at the same level of end-expiratory pressure, mean PaO2 increased significantly (p less than 0.05) and mean physiological shunt decreased (p less than 0.05). In nine of 11 instances, cardiac output was higher on CPAP than on a corresponding level of PEEP. Thus CPAP was more effective than the same amount of PEEP in improving arterial oxygenation by the lung without adversely affecting cardiac output.

Adolescent↗
PubMedDate not supplied

Decidual renin secretion is modulated by endothelial cells.

Because decidual renin may regulate uterine blood flow and decidual-endothelial cell proximity exists, we examined the modulation of decidual renin secretion by endothelial cells. Primary human decidual cell cultures were established. The effect of endothelial cells was studied by decidual-endothelial cocultures. Human umbilical endothelial cells were plated in half of the wells containing decidual cells and were then incubated for 24 h in serum-free media. The effect of endothelial cells was also studied by examining cAMP-mediated renin secretion using 10(-5) M forskolin under standardized conditions. We also examined the role of cell-to-cell contact by coculturing endothelial cells directly on decidual cultures and on cell inserts placed in decidual culture wells. The media were assayed for renin by radioimmunoassay (RIA) for angiotensin I (AI) after AI generation under standardized conditions. Statistical differences were analyzed by two-way analysis of variance (ANOVA) with randomized complete block design. Basal renin secretion, expressed as mean +/- SEM was 10.3 +/- 1.0 ng AI/ml/h. cAMP stimulation increased this to 15.5 +/- 1.3 ng AI/ml/h, P < 0.02. Coculture with vascular endothelium increased renin secretion to 24.3 +/- 2.4 ng AI/ml/h, P < 0.001. cAMP stimulation in cocultures increased renin secretion to 38.0 +/- 4.4 ng AI/ml/h, P < 0.002. There was no effect on cell growth as examined by total protein concentrations by coculturing or by cAMP. There was no increase in renin secretion when endothelial cells were cocultured using cell well inserts. Our data suggest that decidual renin secretion is increased by the presence of endothelial cells in direct contact with decidual cells. This supports a concept that in vivo-decidual-endothelial interaction may modulate decidual renin secretion and thereby influence regulation of uterine blood flow.

Analysis of Variance↗
PubMedDate not supplied

Pseudogout.

Explore the source record for details and available documents.

Acromegaly↗
PubMedDate not supplied

Permeability changes following ischemia-reperfusion injury in the rabbit hindlimb.

Changes in permeability following ischemia-reperfusion injury were assessed in the intact rabbit hindlimb by measuring the transvascular clearance of 125I-labeled rabbit serum albumin. Ischemia was induced for periods of 1 or 2 hours by use of a pneumatic tourniquet inflated to 300 mmHg. Following ischemia, the limb was reperfused for 1, 2, or 3 hours. The albumin clearance in the gastrocnemius muscle of control rabbits was 5.1 +/- 0.7 (mean +/- SEM) microliters/hr/g dry weight. Following 1 hour of ischemia and reperfusion, muscle albumin clearance rose to 71.4 +/- 26 microliters/hr/g dry weight which was not significantly different from those animals that underwent 2 hours of ischemia. Muscle albumin clearance continued to be elevated following 2 hours of reperfusion; however, it returned toward control levels after 3 hours of reperfusion. These data suggest there is a transient increase in albumin permeability following ischemia-reperfusion injury in skeletal muscle.

Animals↗
PubMedDate not supplied

Decreased morbidity associated with retroperitoneal exclusion treatment for abdominal aortic aneurysm.

A prospective randomized study has been carried out to compare the retroperitoneal (RP) and the transperitoneal (TP) approaches to infrarenal abdominal aortic aneurysms (AAA). From November 1988 to July 1989, 27 patients were randomized to one or the other group. Twelve patients underwent TP resection of their AAA; 11 of these were performed using the open aneurysmorrhaphy technique. The RP approach was used in 15 patients, 12 of whom had the exclusion technique performed. Enteral feeding was resumed on the second postoperative day in the RP group compared to the fourth postoperative day in the TP group; the difference was statistically significant (p less than 0.02). Statistically significant differences were also present in the estimated blood loss (516 cc in the RP group versus 1127 cc in the TP group) in the blood transfusion requirement (p less than 0.05). This prospective randomized study comparing TP and RP approaches to AAA showed that the RPE approach had less blood loss, less transfusion requirement, and earlier resumption of enteral feeding than the TP approach. We feel the RPE technique is safe and efficient in the treatment of infrarenal abdominal aortic aneurysm.

Aged↗
PubMedDate not supplied

Carotid bifurcationplasty: an alternative to patching.

Patching of carotid endarterectomies has been advocated as a means of both facilitating secure closure and minimizing recurrent stenosis. Most vascular surgeons occasionally, if not always, patch selected carotid arteries. However, patching requires the surgeon to utilize either prosthetic material (Dacron or PTFE), which is relatively thrombogenic, or autogenous vein, which requires a second operative field and available saphenous vein at the ankle. Bifurcationplasty, otherwise known as bifurcation advancement, has been used as an alternative to patching at our institution over the past four years. This technique, which involves the use of the opened, endarterectomized external carotid artery as an autogenous in-continuity patch for the internal carotid artery, obviates the need for prosthetic materials and saphenous vein alike. This procedure has been performed 30 times over a 4-year period (1987-91). During this time, 280 carotid endarterectomies were performed. A vein patch or Dacron was used in four cases early in this series. Bifurcationplasty was also the procedure of choice for repeat carotid endarterectomy, and was performed in five cases of recurrent stenosis after direct closure. In a follow-up period averaging 22 months (range 1-48), there were no instances of symptomatic restenosis. We feel that bifurcationplasty is an easily performed autogenous alternative to conventional patch closure of the carotid artery.

Carotid Arteries↗
PubMedDate not supplied

Left retroperitoneal exposure for distal mesenteric artery repair.

Distal disease in the mesenteric arteries has usually been repaired transabdominally since it is believed that only the proximal centimeter of each vessel is accessible through the retroperitoneum. We treated five patients with chronic visceral ischemia and lesions extending beyond the orifice using a retroperitoneal approach. Exposure was obtained with a left flank incision through the tenth interspace. The left crus of the diaphragm was divided in order to control the supraceliac aorta. The mesenteric vessels were identified and dissected until their entrance into the peritoneum. There were no difficulties in exposing the superior mesenteric artery (SMA) as it coursed under the pancreas and over the duodenum for an approximate length of 5 to 10 cm. The uncinate process of the pancreas was not a limiting factor for exposure of the SMA in this region and further distal exposure could be obtained by incising the peritoneum. The trifurcation of the celiac artery and the splenic artery were accessible through this exposure; however, only the first centimeter of the hepatic and gastric branches could be reached. Revascularization was performed with endarterectomy (2 patients) and bypass (3 patients). Bowel viability was assessed at the conclusion of the procedure by incising the peritoneum. There were no complications from this exposure and no patient required reoperation for ischemic bowel. We conclude that the left retroperitoneal approach is not only acceptable for orifice lesions but is also applicable for distal disease.

Blood Vessel Prosthesis↗
PubMedDate not supplied

Large diameter expanded polytetrafluoroethylene grafts for infrarenal aortic aneurysm surgery.

The performance of an expanded polytetrafluoroethylene (ePTFE) graft used for aortic aneurysm replacement was evaluated. ePTFE grafts were implanted in 241 patients undergoing infrarenal abdominal aortic aneurysm (AAA) repair. Sixty patients were operated as emergencies for aneurysm rupture and 181 electively. One hundred and fourteen bifurcated and 127 tube grafts were inserted. The transperitoneal approach was used in 64 cases and the remainder were placed using a retroperitoneal approach. There was a one-month mortality of 2.8% in elective and 20% in emergency cases. Median follow-up was 26 months. Specific graft complications included one infected graft resulting in a graft-enteric fistula. No graft rupture, degeneration, dilatation, pseudoaneurysm or late graft limb thromboses were observed in up to 7 years of follow-up. The aortic ePTFE prosthesis demonstrated satisfactory performance over the period studied.

Aged↗