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Biomedical subjects

W J Fry

Publications and source records attributed to W J Fry.

At least 73 records · Page 4Linked to original sources
PubMed1979

Vertebral arteriovenous fistula associated with an anomalous arterial vessel.

The widespread use of angiography in patients sustaining vascular trauma has demonstrated an increased incidence in vertebral artery injuries. With the improvement in peripheral vascular techniques and the utilization of extended exposure of the vertebral artery, aggressive therapy now is generally advocated. While new concepts continue to evolve, it becomes important to report anatomical variants that are not commonly recognized. An anomalous vessel originating from the proximal subclavian artery is reported. Initial ligation of a semmingly normal vertebral artery failed to control the fistula which was fed by the anomalous vessel. The importance of complete arteriographic studies is stressed. In particular, it is important to visualize the vascular anatomy both proximally and distally to the injury in order that anomalous vessels are recognized. Arteriography will improve diagnosis, help plan operative or nonoperative therapy, and decrease the incidence of missed injuries and complications.

Arteriovenous Fistula↗
PubMed1979

Hypotension and hypertension as consequences of baroreceptor dysfunction following carotid endarterectomy.

Arterial pressure regulation is often labile following carotid endarterectomy. Hemodynamic data from 100 consecutive endarterectomies allowed definition of three distinct postoperative blood pressure responses. A hypotensive response (group I) affected 28 patients in whom mean arterial pressure decreased from 168 +/- 29/90 +/- 15 mm Hg before operation to 110 +/- 21/68 +/- 16 mm Hg after operation (P less than 0.001). Maximum hypotension occurred 5.3 hours after endarterectomy. The preoperative pulse, 80 +/- 9 beats/min, fell to a low of 64 +/- 12 beats/min after operation (P less than 0.001). A significant hypertensive response (group II) affected 19 patients in whom mean blood pressure rose from 160 +/- 29/87 +/- 15 to 223 +/- 32/110 +/- 22 mm Hg (P less than 0.001). Maximum hypertension was noted 2.3 hours after endarterectomy. This was unaccompanied by significant pulse changes. Fifty-three patients remained normotensive (group III). Their preoperative blood pressure (150 +/- 14 mmHg). Fluctuations in pressure did not correlate with age, indication for operation, or degree of ipsilateral and contralateral carotid arterial stenosis. Postendarterectomy hypotension and hypertension appear to represent transient baroreceptor dysfunctions.

Aged↗
PubMed1979

Differing actions of nitroprusside and D-600 on tension and 45Ca fluxes in canine renal arteries.

Administration of nitroprusside (NP) subsequent to induction of contraction in canine renal arterial strips with norepinephrine (NE) yielded a dose-dependent relaxation and with 80 mM potassium (KCl) yielded only a small degree of relaxation. The effect elicited with 0.1 mM NP was significantly greater for responses obtained with NE (68%) than for those with KCl (12%). However, responses of muscles pretreated for 5 min with NP to NE to KCl were reduced by 23 and 31%, respectively. The relaxant effect of NP persisted after incubation with D-600 and/or 30 min of a 0-Ca plus 0.05 mM EDTA solution (low EDTA). Neither D-600 nor NP altered 45Ca uptake in the absence of stimulatory agents. Efflux of 45Ca (into low EDTA solution) was decreased by NP in a maintained manner but was unaffected by D-600. The NE-induced decrease in 45Ca efflux (but not that with KCl) was blocked by NP. However, changes in 45Ca efflux elicited with KCl or NE were not affected by D-600. In contrast to D-600 (which is known to inhibit increased Ca++ entry associated with some stimulatory conditions), NP acts in a manner that is relatively independent of uptake of extracellular Ca++. Thus, these two vasodilators appear to affect Ca++ utilization by different mechanisms and, presumably, in an additive manner.

Animals↗
PubMed1978

The validity of normal arteriography in penetrating trauma.

The detection of underlying arterial injury is a major problem in the management of penetrating trauma. Arteriovenous fistula and false aneurysm are late sequelae of unrepaired injuries. The diagnostic accuracy of arteriography in clinically occult injury has not been defined. One hundred and seventy-seven patients with 183 penetrating extremity wounds underwent arteriography followed by operative vessel exploration. Arteriogram/operation correlation demonstrated 36 true-positive, 132 true-negative, 14 false-positive, and one false-negative arteriogram. Arteriography is sufficiency sensitive to exclude the presence of arterial injury in patients with equivocal clinical signs of injury. The radiographic changes are often sublte and diagnostic accuracy demands attention to the details of technique and interpretation. Unequivocal clinical signs of arterial injury and any arteriographic abnormality are indications for operative exploration.

Angiography↗
PubMed1978

Ultrastructure of medial smooth muscle and myofibroblasts in human arterial dysplasia.

Ultrastructural characteristics of 20 dysplastic human renal arteries were documented. Loss of smooth muscle with collection of fibrous connective tissue predominated in medical fibrodysplasia, whereas excessive accumulations of elastic fibrils typified perimedial dysplasia. Myofibroblasts were a unique feature of both forms of arterial dysplasia. These modified smooth muscle cells seemed to be the source of abnormal connective tissue synthesis. Transformation of medial smooth muscle cells to myofibroblasts represented a morphologic continuum. Intramedial vasa vasorum were often isolated from surrounding cellular elements by unusual amounts of mural ground substances. The results of this study lend further support to the hypothesis that ischemia and direct physical forces effect hormonally altered cells in the pathogenesis of arterial dysplasia.

Adult↗
PubMed1978

Portal hypertension following renal transplantation.

Portal hypertension and variceal hemorrhage may be found in the renal transplant patient with chronic liver disease. The development of portal hypertension was found to occur after long-term graft survival without significant rejection. The development of positive cytomegalic virus and negative hepatitis-associated antigen appeared to be common. Splenomegaly and prominent venous collateral were the most frequent physical findings, while ascites and hepatomegaly were less frequent. Portasystemic decompression can be performed successfully, however, the mortality and morbidity appear to be higher for this group than for other cirrhotic patients with comparable hepatic reserve.

Adult↗
PubMed1978

Effects of norepinephrine, dopamine and potassium on tension and 45Ca fluxes in canine and rabbit renal arteries.

The action and interactions of three vasoconstrictors, norepinephrine (NE), dopamine (DA) and elevated potassium ion (K+) on contractile responses and associated 45Ca movements were investigated in isolated rabbit and canine renal arteries (RA). Dose-response curves indicate that NE is 39 times more potent than DA in canine RA and 122 times more potent in rabbit RA. Prior exposure to 80 mM K+ did not prevent contractile responses to NE or DA but, conversely, K+ -induced responses did not occur after exposure to NE or DA. Responses to NE persisted after maximum DA-induced contractions but only a small response to DA was observed after a maximum NE-induced contraction. After 30 to 60 min in either a O-Ca or a O-Ca plus 0.05 mM EDTA solution, contractile responses were differentially inhibited (K+ more than DA more than NE). Efflux of 45Ca into a O-Ca plus EDTA solution was qualitatively similar in canine and rabbit RA. Addition of K+, DA or NE decreased the rate of 45Ca efflux in both RA; phentolamine abolished the NE-induced decrease and had no effect on the K+-induced decrease. The observed decrease in 45Ca efflux may reflect an inward shift of 45Ca from membrane binding sites. The mechanisms by which this effect is obtained appear to differ for K+, DA and NE. The differing actions of NE and DA cannot be explained solely by variations in potency at a singel type of receptor.

Animals↗
PubMed1977

Renal artery dissections.

Renal artery dissections encountered in 15 patients, aged 3 to 75 years, were categorized as to pathogenesis (blunt abdominal trauma, catheter injury, and spontaneous). Blunt traumatic dissections (seven patients) were characterized by hypertension, gross hematuria, and pain. Catheter-induced dissections (four patients) were asymptomatic, although two exhibited accelerated hypertension. Spontaneous dissections (four patients) were all associated with preexistent arterial disease. Symptoms in these patients were uncommon, despite accelerated hypertension in three cases. Intravenous pyelography lacked specific diagnostic value for renal artery dissections. Early arteriographic examination proved essential in diagnosis and surgical treatment. Criteria for operative intervention included existence of technically correctable dissections causing (1) hemodynamically significant occlusions of the main or major segmental renal arteries, (2) documented renovascular hypertension, or (3) significant deterioration of renal function.

Adult↗
PubMed1977

Pneumoperitoneum complicating mechanical ventilator therapy.

Subdiaphragmatic air arouses the clinical suspicion of a perforated intra-abdominal viscus. In patients with respiratory failure requiring mechanical ventilation, the retroperitoneal dissection of air from the mediastinum may give rise to radiologic evidence of subdiaphragmatic emphysema. The present report describes four patients with this syndrome. In three of them, a perforated gastric or duodenal ulcer was initially suspected. None of these three patients underwent surgery. Autopsy examinations in two patients revealed extraperitoneal subdiaphragmatic emphysema with secondary rupture into the free peritoneal cavity. The third patient had an uneventful recovery and was discharged from the hospital. In a fourth patient, signs of peritonitis prompted an exploratory laparotomy. No perforation of an intraperitoneal viscus was identified. Upper gastrointestinal contrast roentgenography and peritoneal lavage may help determine the etiology of subdiaphragmatic air in patients undergoing therapy with a mechanical ventilator.

Adolescent↗
PubMed1977

Surgical treatment of renovascular hypertension.

Two hundred sixty-four patients exhibiting renal artery occlusive disease underwent operation for renovascular hypertension between 1961 and 1977. Included were 27 pediatric patients. Fibrodysplastic disease affected 132 adults. Atherosclerotic lesions affected 51 patients with and 54 patients without clinically overt extrarenal arteriosclerotic cardiovascular disease. Ischemic kidney renin hypersecretion (renal: systemic index greater than 0.48), associated with suppressed contralateral kidney renin secretion (renal: systemic index approaching 0.0) predicted curability most reliably. Three hundred forty-eight operations were performed, of which 297 were primary and 51 were secondary procedures. Nephrectomy was initial therapy in 15 cases. Three operative deaths occurred among 51 patients manifesting overt extrarenal arteriosclerotic disease. No operative mortality was encountered among the other 213 patients. Surgical benefits were afforded 96% of pediatric patients and adults with fibrodysplastic disease, 91% of patients with focal renal arteriosclerosis, and 73% of those exhibiting overt extrarenal arteriosclerosis.

Adult↗
PubMed1977

Multiple subcritical arterial stenoses: effect on poststenotic pressure and flow.

Diminished poststenotic pressure and flow accompanied experimental application of multiple subcritical arterial stenoses in series. Effects of additional stenoses, causing equivalent constrictions, were cumulative in a nonlinear fashion. Seven-hundred-twenty measurements were performed using 10 cm ileofemoral canine arterial segments in vitro and in vivo with pulsatile and nonpulsatile blood flow. Pressures and flow volumes utilized for testing were within normal physiologic ranges. Data analysis included correlations of experimental observations with predictions generated from a theoretic hydraulic model. Kinetic energy losses with multiple subcritical stenoses were associated with decreased pressure and flow. Poststenotic pressure decreased as much as 51% in some experiments. Diminutions in flow paralleled pressure changes. Measured pressure changes were nonlinear and followed mathematic predictions of appreciable but lesser effects of added stenoses. Hemodynamic alterations of magnitudes documented in this study assume clinical importance. The assumption that a solitary critical stenosis must exist before significant hemodynamic changes occur is no longer tenable.

Animals↗
PubMed1977

Femoropopliteal bypass for limb salvage.

A total of 148 femoropopliteal bypass procedures followed for a minimum of 2 years yielded a patency rate of 61.9 percent among survivors. Diabetes mellitus, cigarette smoking, quality of the outflow, or prior inflow procedures did not influence patency rate. Results were less satisfactory in women and when cloth grafts were used. The indications for femoropopliteal bypass require continuing careful assessment.

Adult↗