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Biomedical subjects

J C Stanley

Publications and source records attributed to J C Stanley.

At least 163 records · Page 9Linked to original sources
PubMed1985

Nonpenetrating subclavian artery injuries.

Nonpenetrating subclavian artery trauma, a potentially catastrophic injury, has been recognized more frequently with the liberal use of angiography in evaluating blunt cervicothoracic trauma. Six patients, five men and one woman, recently underwent surgical treatment at the University of Michigan Hospital for blunt injury of the subclavian artery. The diagnoses were established by arteriography. Physical findings, chest roentgenograms, and results of noninvasive vascular evaluation were found to be nonspecific or unreliable. Operative treatment with resection of the injured arterial segments and either primary anastomosis or bypass grafting resulted in restoration of distal, upper extremity blood flow in all of the cases. One patient died 20 days after trauma from a severe associated cerebral injury. Among the five survivors, residual soft tissue and neurologic injury compromised full recovery in three. Thus, only two of the six patients survived without sequelae, a fact that underscores the seriousness of this type of subclavian artery injury.

Accidents, Traffic↗
PubMed1985

Enhanced endothelialization of Dacron grafts by external vein wrapping.

The efficacy of external vein wrapping of vascular grafts in promoting the development of a luminal endothelial surface was assessed in 12 dogs who underwent thoracoabdominal bypasses with 26-29 cm X 6-mm i.d. double-velour knitted Dacron grafts. In group I (n = 6) 6-cm segments of the grafts were wrapped with autologous jugular vein with its endothelial surface applied against the outside of the graft. In group II (n = 6) the wrap procedure was performed using abdominal wall fascia. The degree and character of graft incorporation was quantitated in all prostheses at 28 days postimplantation. Group I vein wrap prostheses demonstrated uniform endothelial surface coverage in the vein wrap area (means = 88%) that was significantly greater (P less than 0.04) than coverage in adjacent unwrapped segments (means = 48%). Group II fascial wrap grafts demonstrated variable endothelial coverage in the wrapped area (means = 48%) that was consistently less than in adjacent unwrapped portions (means = 62%), and significantly less than vein wrap sections of group I animals (P less than 0.04). No significant differences existed in endothelial coverage of unwrapped regions of group I and II grafts. This investigation documented that wrapping knitted Dacron grafts with vein enhanced endothelialization of their luminal surface.

Animals↗
PubMed1985

Comparative hemodynamic effects of selective superior mesenteric arterial and peripheral intravenous glucagon infusions.

This experiment was designed to determine whether any hemodynamic benefits attend administration of equal pharmacologic doses of glucagon (1 micrograms/kg/m) by continuous intravenous infusion (Group I, n = 6) versus selective intraarterial infusion (Group II, n = 6) via the superior mesenteric artery (SMA) in dogs. Cardiac output, heart rate, mean arterial pressure, total peripheral resistance, pulmonary vascular resistance, superior mesenteric artery flow (SMAQ), SMA vascular resistance, and portal venous pressure were measured at baseline (BL) and at 5, 15, 30, and 45 min during glucagon infusion. SMAQ virtually doubled at 5 min from a baseline of 570 +/- 60 ml/min to 1158 +/- 146 ml/min in Group I (P less than 0.001), and from a baseline of 527 +/- 171 to 1018 +/- 331 ml/min in Group II (P less than 0.002). SMAQ was significantly higher in Group I at 30 and 45 min compared to Group II (P less than 0.03) despite similar peripheral plasma glucagon levels. SMA vascular resistance was significantly lowered in both groups, with a greater reduction occurring during intravenous glucagon administration at 45 min (P less than 0.05). Changes in systemic hemodynamic parameters, as well as glucagon and glucose levels were not statistically different between Groups I and II at any time period. Glucagon is a potent mesenteric vasodilator and the resultant profound splanchnic hemodynamic effects are as marked during intravenous administration as during selective SMA infusion.

Animals↗
PubMed1985

Celiac artery aneurysms: historic (1745-1949) versus contemporary (1950-1984) differences in etiology and clinical importance.

Celiac artery aneurysms were encountered in nine patients, ranging in age from 39 to 76 years, at the University of Michigan Medical Center between 1961 and 1983. Developmental defects and atherosclerosis were etiologic factors in six cases. Four patients were without symptoms, whereas five experienced abdominal pain, including one with a ruptured aneurysm. Eight patients were subjected to surgical treatment; no deaths occurred and symptoms were resolved in all patients. A literature review of 108 celiac artery aneurysms revealed two distinct subgroups. Among 60 celiac artery aneurysms encountered before 1950, representing the historic era, 40% were infectious (usually luetic), 7% were traumatic, and 52% were of undetermined cause. Most were symptomatic, 87% ruptured, and 95% were diagnosed at postmortem examination. The contemporary era since 1950 consisted of 48 cases, including nine in the Michigan experience. Congenital or developmental medial defects of the arterial wall and atherosclerosis were the most common causes of aneurysms. Most aneurysms in the contemporary period were either asymptomatic or accompanied by vague abdominal discomfort. Rupture affected 13% of those aneurysms. Operative therapy was successfully undertaken in 91% of 43 patients during the contemporary era, including eight in the present series.

Adult↗
PubMed1985

The effect of dietary guar gum on the activities of some key enzymes of carbohydrate and lipid metabolism in mouse liver.

The effects of a 100 g/kg substitution of guar gum on the body-weight gain, food consumption and faecal dry weight of mice fed on a high-sucrose diet and on the activities of hepatic glucose-6-phosphate dehydrogenase (EC 1.1.1.49), 6-phosphogluconate dehydrogenase (EC 1.1.1.44), malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+) (EC 1.1.1.40), ATP-citrate (pro-3S)-lyase (EC 4.1.3.8), 6-phosphofructokinase (EC 2.7.1.11), pyruvate kinase (EC 2.7.1.40) and fructose-1, 6-bisphosphatase (EC 3.1.3.11) were studied. Guar gum had no effect on body-weight gain or food consumption but increased faecal dry weight. Guar gum increased the activities of glucose-6-phosphate dehydrogenase, malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+) and 6-phosphofructokinase expressed on a wet-liver-weight basis. Guar gum increased the activities of glucose-6-phosphate dehydrogenase, malate dehydrogenase (oxaloacetate-decarboxylating)(NADP+), ATP-citrate (pro-3S)-lyase and 6-phosphofructokinase expressed on a liver-protein basis. Guar gum increased the activities of glucose-6-phosphate dehydrogenase and malate dehydrogenase (oxaloacetate-decarboxylating)(NADP+) expressed on a body-weight basis. These results suggest that guar gum increases the flux through some pathways of hepatic lipogenesis when mice are fed on high-sucrose diets.

Animals↗
PubMed1985

The effect of dietary bagasse on the activities of some key enzymes of carbohydrate and lipid metabolism in mouse liver.

The effects of a 100 g/kg diet substitution of bagasse on the body-weight gain, food consumption and faecal dry weight of mice given a high-sucrose diet and on the activities of hepatic glucose-6-phosphate dehydrogenase (EC I.I.I.49), 6-phosphogluconate dehydrogenase (EC I.I.I.44), malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+) (EC I.I.I.40), ATP-citrate (pro-3S) lyase (EC 4.I.3.8), 6-phosphofructokinase EC 2.7.I.II), pyruvate kinase (EC 2.7.I.40) and fructose-1,6-bisphosphatase (EC 3.I.3.II) were studied. Bagasse had no effect on body-weight gain, food consumption or faecal dry weight. Bagasse decreased the activities of glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and phosphofructokinase expressed on a wet weight basis and on a protein basis. Bagasse decreased the activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase expressed on a body-weight basis. These results suggest that bagasse decreases the flux through some pathways of hepatic lipogenesis when mice are given high-sucrose diets.

Animals↗
PubMed1985

Actuarial analysis of variables associated with rupture of small abdominal aortic aneurysms.

This study identified risk factors associated with rupture of small abdominal aortic aneurysms in patients initially selected for nonoperative management. Sixty-seven patients, 53 men and 14 women, 50 to 91 years of age (mean 72 years) were followed 3 to 99 months (mean 36 months). All patients underwent serial aortic ultrasonography. The annual rate of aneurysm rupture was 6%, with an annual mortality rate caused by rupture of 5% and an annual mortality rate caused by coexistent disease of 6%. Thirty potential risk factors, including blood pressure, aneurysm size measured by ultrasonography, rate of aneurysm expansion, smoking, serum cholesterol levels, and cardiac, pulmonary, and renal risks, were analyzed by Cox proportional hazards regression to identify variables related to rupture. Aneurysm anteroposterior expansion rates varied from 0 to 1.5 cm/year but were not different in aneurysms that ruptured. Only diastolic blood pressure, initial aneurysm anteroposterior diameter, and degree of obstructive pulmonary disease were independently predictive of rupture (p less than 0.05, Wald test). With these data, actuarial rupture rates were predicted for patients with selected values of these three covariates. Predicted 5-year rupture rates varied from 2% when these risk factors were absent to 100% when all three risk factors were significant. Obstructive pulmonary disease, initial aneurysm size, and diastolic hypertension must be evaluated prospectively to assess their accuracy in predicting small aneurysm rupture.

Actuarial Analysis↗
PubMed1985

Reoperation for complications of renal artery reconstructive surgery undertaken for treatment of renovascular hypertension.

Seventy-two secondary operations for complications of prior renal artery reconstructive surgery were undertaken in 58 patients. This experience evolved from the management of 373 patients who underwent 425 primary operations for renovascular hypertension. Secondary operations were performed 10 times in pediatric patients following 42 primary procedures (24%); 44 times in adult fibrodysplastic patients following 199 initial operations (22%); and 18 times in atherosclerotic patients after 184 primary operations (10%). The overall reoperation rate was 15.5% (58 of 373 patients). Reoperation typically followed persistent or recurrent hypertension caused by graft thromboses, perianastomotic graft narrowing, or progressive nonanastomotic graft stenoses. Aneurysmal deterioration of vein grafts was an uncommon reason for reoperation. Secondary reconstructions included nephrectomy (31), bypass with vein grafts (15) or prosthetic grafts (8), angioplasty or reimplantation (12), thrombectomy (4), and operative dilation (2). Benefits regarding hypertension control were afforded 91% of these patients. One death occurred among the 72 reoperations, representing a 1.4% operative mortality rate. Reoperative renal artery reconstructive surgery for complications of renal revascularization may present formidable technical problems. Early diagnosis and prompt reoperation with exacting vascular surgical techniques are most likely to provide optimal results.

Adolescent↗
PubMed1985

Inferior mesenteric artery aneurysms.

Two patients were treated for asymptomatic aneurysms of the inferior mesenteric artery during reconstructive operation for infrarenal aortic disease. These lesions were discovered incidentally during arteriographic study in one case and during operation in the second case. Including these two patients, the number of reported inferior mesenteric artery aneurysms now totals 13. The etiology, manifestations, and treatment of the currently reported aneurysms are compared with eight previously published cases in which detailed clinical data were presented. Although the natural history of these rare aneurysms remains undefined, operative intervention appears appropriate for all mycotic lesions and certain other aneurysms, such as those in patients undergoing aortic operation.

Adult↗
PubMed1984

Activities of glucokinase and hexokinase in mammalian and avian livers.

A radiochemical assay for glucokinase activity was developed for use in high-speed supernatants of liver. The maximum activities of glucokinase ranged from 0.4 to 3.8 mumol/min per g fresh wt. at 30 degrees C in some avian and mammalian livers, including pigeon, guinea pig and man, in which previous reports indicated zero activities. The reported maximum rates of hepatic glycogen synthesis in livers of rat and man in vivo are similar to the calculated glucokinase activities at 10mM-glucose; therefore glucokinase activity should not limit glycogen synthesis from glucose.

Animals↗
PubMed1984

The influence of starvation and tryptophan administration on the metabolism of phenylalanine, tyrosine and tryptophan in isolated rat liver cells.

Liver cells from fed Sprague-Dawley rats metabolized phenylalanine, tyrosine and tryptophan at rates consistent with the known kinetic properties of the first enzymes of each pathway. Starvation of rats for 48 h did not increase the maximal activities of phenylalanine hydroxylase, tryptophan 2,3-dioxygenase and tyrosine aminotransferase in liver cell extracts, when results were expressed in terms of cellular DNA. Catabolic flux through the first two enzymes was unchanged; that through the aminotransferase was elevated relatively to enzyme activity. This is interpreted in terms of changes in the concentrations of 2-oxoglutarate and glutamate. Cells from tryptophan-treated animals exhibited significant increases in the catabolism of tyrosine and tryptophan, but not of phenylalanine. The activities of tyrosine aminotransferase and tryptophan 2,3-dioxygenase were also increased, although the changes in flux and enzyme activity did not correspond exactly. These results are discussed with reference to the control of aromatic amino acid catabolism in liver; the role of substrate concentration is emphasized.

Amino Acids↗
PubMed1984

Tryptophan aminotransferase activity in rat liver.

By using an antiserum raised against rat liver tyrosine aminotransferase, it was shown that about 60% of tryptophan aminotransferase activity in rat liver extracts is catalysed by this enzyme. Induction of tryptophan aminotransferase activity by intraperitoneal injections of tryptophan or triamcinolone can be entirely attributed to the effects of these agents on tyrosine aminotransferase. The origin of the other 40% of tryptophan aminotransferase activity remains to be established. This activity increases after starvation for 48 h. It is unlikely that tryptophan transamination plays a quantitatively important role in the metabolism of tryptophan by the liver.

Animals↗
PubMed1984

Intermittent claudication. Current results of nonoperative management.

We reviewed the clinical course of 91 men with mild intermittent claudication who had been followed up for at least six months without operation. During 2.5 years' mean follow-up, 60% of the patients had more severe claudication. Actuarial analysis revealed an annual mortality of 4.5% and an annual operation rate of 9%. Historical factors, including age, race, smoking, exercise, diabetes, hypertension, and the ankle-brachial index (ABI), were analyzed to determine if these variables could predict clinical outcome. Only cigarette smoking, exercise, and the ABI were significant in this regard. Patients who had smoked at least 40 pack-years had an operation rate 3.3 times higher than those who smoked less. Major daily exercise was associated with stable claudication. The initial ABI did not correlate with clinical outcome. A subsequent decrease in the ABI of at least 0.15, however, was associated with an operation rate 2.5 times higher and a symptom progression rate 1.8 times higher than patients without this change in the ABI. When regression analysis was used, the preceding variables were only 63% to 79% accurate in predicting the clinical outcome of individual patients. Careful follow-up of patients with intermittent claudication is therefore recommended to allow timely operative intervention when required.

Adult↗
PubMed1984

Early derangements of arteriovenous anastomotic and capillary blood flow in the canine hindlimb induced by supplemental pentobarbital anesthesia.

Vasoactive effects of supplemental pentobarbital anesthesia in the canine hindlimb microcirculation were documented in two groups of animals previously anesthetized with 30 mg/kg pentobarbital: Group I with a 5 mg/kg intravenous (iv) bolus of pentobarbital (n = 8) and Group II with a 5 mg/kg 2-min iv infusion of pentobarbital (n = 7). In Group I, measurements at baseline (BL) and 5, 15, 20, and 30 min (min) following pentobarbital administration included cardiac output, mean arterial pressure, total peripheral vascular resistance, common femoral artery flow (CFAQ) and resistance (CFAR), percentage hindlimb arteriovenous anastomotic shunt (AVA%), absolute shunt flow (AVAQ), and hindlimb nutrient capillary flow (NCQ). In Group II these same measurements were made, but the study was continued until all hindlimb hemodynamic parameters returned to control values. CFAQ, AVA%, AVAQ, and NCQ were significantly increased, and CFAR was decreased in both groups. CFAQ and NCQ remained significantly elevated at 30 min in Group I. In Group II CFAR, AVA%, and AVAQ remained elevated at 30 min, but did return to BL by 40 min, as did all other hindlimb hemodynamic parameters measured. Pentobarbital resulted in both AVA and arteriolar dilation, with an increase in the percentage total flow distributed to AVAs. These alterations of microcirculatory flow should be considered during investigations of the distribution of peripheral blood flow, as well as during metabolic studies assessing arteriovenous substrate differences, if interpretative errors are to be avoided.

Anesthesia↗
PubMed1984

Interaction of hindlimb blood flow, A-V shunting and A-V oxygen difference.

The interactions of blood flow, A-V O2 difference (AVDO2), and A-V shunting were measured in normal hindlimbs of nine anesthetized dogs. An aorto-iliac nonpulsatile perfusion pump was used to change femoral artery blood flow from zero (collateral flow only) to twice its baseline level. Femoral AVDO2 was measured by in-line spectrophotometric O2 analysis. A-V shunting was measured with radio-labeled microspheres. Systemic hemodynamic parameters and temperature remained constant during the experiments. Despite changes in femoral mean arterial pressure (160 to 54 mm Hg) and AVDO2 (1.8 to 8.2 ml O/2/dl) that occurred with femoral blood flow reduction, peripheral A-V shunting remained constant at 4.1-5.5%. Alpha-adrenergic ablation (sympathectomy) was used to increase A-V shunting (up to 20%) during part of this experiment. When hindlimb blood flow was normal or increased, autoregulation of O2 extraction maintained constant hindlimb O2 consumption, despite sympathectomy-induced changes in A-V shunting. Subnormal femoral artery blood flow reduced hindlimb O2 consumption, and in this setting the increased A-V shunting further decreased femoral AVDO2 and O2 consumption. Since AVDO2 is dependent upon both blood flow and the variable efficiency of cellular O2 extraction, it cannot be used as an accurate indicator of A-V shunting. Direct microsphere techniques should be applied to A-V shunt measurements in clinical settings where A-V shunting is suspected.

Animals↗
PubMed1984

Effects of glucagon and prostacyclin in acute occlusive and postocclusive canine mesenteric ischemia.

Effects of glucagon and prostacyclin (PGI2) were studied in anesthetized dogs during sequential occlusive and postocclusive mesenteric ischemia induced by 90 min of tourniquet stenosis of the superior mesenteric artery (SMA). After 30 min of SMA stenosis, glucagon (1 microgram/kg/min, n = 7), PGI2 (30 ng/kg/min, n = 7), or saline (1 ml/min, n = 3) was infused intravenously for 30 min, followed by 30 min of continued ischemia. SMA flow and distal SMA pressure ( SMAP ) decreased 76% with SMA stenosis (P less than 0.01). Ileal wall flow measured by radiolabeled microspheres decreased from 45 to 13 ml/min/100 g (P less than 0.01); mesenteric AV O2 difference ( AVDO2 ) increased from 5.1 to 10.1 ml/dl (P less than 0.01); and mesenteric O2 consumption (VO2) decreased by 48% (P less than 0.05). Glucagon infusion caused a further decrease in ileal wall flow, to 10 ml/min/100 g (P less than 0.05), and an increase in AVDO2 to 11 ml/dl (P less than 0.05), despite a 22% increase in cardiac output. PGI2 caused a similar decrease in ileal wall flow and an increase in AVDO2 , although these were not statistically significant. Saline infusion caused no change in measured variables. In the second phase of this study, SMA blood flow was restored by tourniquet release. After animals had stabilized for 30 min, a repeat 30-min drug infusion was studied. In this postocclusive period, persistent gut ischemia was indicated by a reduction in VO2 to 76% of original baseline, associated with a 50% decrease in both CO and SMAQ . Intravenous infusion of glucagon at this time increased SMAQ by 195% (P less than 0.05) and resulted in a return of VO2 to its original baseline level. PGI2 infusion caused a 21% increase in SMAQ and a 16% decrease in AVDO2 (NS), but had no significant effect on VO2. Glucagon was effective in the management of postocclusive mesenteric ischemia but appeared to have a detrimental effect on ileal blood flow in severe occlusive ischemia.

Acute Disease↗