Biomedical subjects

R D Schultz

Publications and source records attributed to R D Schultz.

At least 55 records · Page 3Linked to original sources

PubMed1989

Effects of vaccines on the canine immune system.

The effects of several commercially available polyvalent canine vaccines on the immune system of the dog were examined. The results demonstrated that the polyvalent vaccines used in this study significantly suppressed the absolute lymphocyte count and that most of the polyvalent vaccines significantly suppressed lymphocyte response to mitogen, but had no effect on natural effector cell activity, neutrophil chemiluminescence, nor antibody response to canine distemper virus. The individual vaccine components from the polyvalent vaccines when inoculated alone did not significantly suppress the lymphocyte response to mitogen. However, when canine distemper virus was combined with canine adenovirus type 1 or canine adenovirus type 2, significant suppression in lymphocyte responsiveness to mitogen occurred. The results indicate that interactions between canine distemper virus and canine adenovirus type 1 or canine adenovirus type 2 are responsible for the polyvalent vaccine induced suppression of lymphocyte responsiveness.

Adenoviridae↗

PubMed1989

Natural history of recurrent carotid artery disease.

Controversy exists as to whether early and late recurrent stenosis of the carotid artery represents two distinct types of recurrence or whether it is the same type of lesion detected at different times. Eleven specimens from patients whose carotid arteries were reoperated upon were examined. A temporal sequence was noted: with increasing intervals, the relative presence of areas of myointimal hyperplasia tended to decrease, whereas the relative presence of features of atherosclerosis tended to increase. The clinical data and B-mode ultrasound studies performed from one to 190 months after 210 carotid endarterectomies were reviewed. Twenty-seven carotid arteries (12.9 per cent) exhibited hemodynamically significant restenosis. Three ultrasonographic patterns were described: homogenous soft plaque, homogenous hard plaque and heterogenous plaque. A previous correlation between ultrasonographic and pathologic findings showed the three ultrasound patterns to correlate with myointimal hyperplasia, fibrous atherosclerotic plaque and complex atherosclerotic plaque, respectively. Soft plaques were detected earlier than heterogenous plaques (p less than 0.001). Results from serial studies showed progression of soft plaque to hard or heterogenous plaque, or both. Early and late recurrent lesions are the same type of lesion detected at different intervals. Symptoms of cerebral ischemia are more common at the stage of heterogenous plaque (p = 0.02).

Aged↗

PubMed1989

Operative strategies in patients with symptomatic internal carotid artery occlusion.

A 15-year experience with 98 patients who underwent extracranial artery reconstruction for symptomatic internal carotid artery occlusion is reviewed. Thromboendarterectomy of the occluded carotid artery resulted in unacceptably high mortality and morbidity rates, and long-term patency of the internal carotid artery was rarely achieved. Carotid endarterectomy on the side opposite the occlusion proved to be successful in relieving nonlateralizing symptoms of cerebral ischemia, whereas results were less encouraging in patients with focal symptoms in the hemisphere ipsilateral to the occlusion. External carotid artery reconstruction on the side of the occlusion was successful in relieving focal symptoms. Surgical treatment in patients with symptomatic internal carotid artery occlusion should be planned in each patient on the basis of symptoms and anatomic pattern.

Actuarial Analysis↗

PubMed1989

Popliteal aneurysms.

A 15 year experience with 50 popliteal aneurysms in 36 patients is reviewed. Forty-seven popliteal aneurysms were atherosclerotic while three were related to entrapment of the popliteal artery. Fourteen asymptomatic popliteal aneurysms were observed preoperatively during a mean period of 26 months. Ischemic complications developed in five of these. At admission, 16 limbs were asymptomatic (group 1) while the other 34 limbs presented with ischemic symptoms (group 2). No operation was performed upon three limbs, and another two were surgically explored and amputated. No operative deaths resulted from 45 vascular reconstructions. Results from follow-up study of one to 176 months (a mean of 57 months) revealed a late patency rate of 62 per cent. The late patency rate of autologous saphenous vein (ASV) was 100 per cent; polytetrafluoroethylene (PTFE) and Dacron (polyester fiber) grafts had a patency rate of 74 and 34 per cent, respectively (ASV versus PTFE, p = N.S.; ASV versus Dacron, p less than 0.002). The rate of late salvage of limbs was 88 per cent. The bypass grafts of group 1 and those performed upon limbs with good runoff fared significantly better than others (p less than 0.05 and p less than 0.001). The risk of natural complications of popliteal aneurysms and the good results from surgical treatment suggested that a revascularization procedure in the asymptomatic stage is always recommended. The use of PTFE grafts for repair of popliteal aneurysms is justified when the ASV is not available. The use of Dacron grafts is no longer indicated.

Aged↗

PubMed1989

Subclavian artery revascularization: a comparison between carotid-subclavian artery bypass and subclavian-carotid transposition.

Extrathoracic revascularization has become the most popular form of surgical treatment of symptomatic subclavian disease. Despite the many theoretical advantages, subclavian-carotid transposition (SCT) has not gained wide popularity. During a 15-year period, 46 patients underwent carotid-subclavian bypass (CSB) or SCT for symptoms referable to occlusion of the subclavian artery. Follow-up ranged from 2 to 148 months (mean, 46.9 months). Seven-year actuarial patency rate was 100% for SCT and 86% +/- 7% for CSB (p = NS). Mean operative time and intraoperative blood loss were significantly reduced for SCT (p less than 0.05). After CSB a continuous deterioration of the hemodynamic status of the reconstruction was noted, whereas there were no significant changes after SCT (p less than 0.05). Whenever feasible, SCT should be considered the operation of choice for patients with symptomatic severe subclavian artery disease.

Adult↗

PubMed1988

Combined aortofemoral and extended deep femoral artery reconstruction. Functional results and predictors of need for distal bypass.

In patients with combined aortoiliac and femoropopliteal occlusive disease, severe involvement of the deep femoral artery (DFA) has often been considered an indication for simultaneous aortofemoral and femorodistal bypass grafting. In 73 patients (87 limbs) with multilevel disease, extended DFA reconstruction was performed with aortofemoral bypass. Five-year actuarial patency of the reconstructions and overall five-year actuarial limb salvage were 62.2% and 60.2%, respectively. Of 20 variables tested, four were significantly associated with the functional outcome of the procedures. Multivariate analysis identified two factors as predictive of outcome independently from other variables: preoperative ankle-brachial pressure index and angiographic status of the below-knee popliteal artery. However, in case of reoperation for occluded aortofemoral graft, these factors lost their validity. Extended DFA reconstruction is a valuable and durable procedure able to provide an adequate outflow and distal perfusion. Careful judgment in each clinical situation will aid in selecting a small group of patients in which simultaneous femorodistal bypass is required.

Aged↗

PubMed1988

Ontogeny of mitogen responsive lymphocytes in the bovine fetus.

Bovine fetal lymphocytes were examined for their ability to respond to the mitogens phytohemagglutinin (PHA), Concanavalin A (ConA) and pokeweed mitogen (PWM) in the lymphocyte blastogenesis test (LBT). PHA-, Con A- and PWM-responsive lymphocytes appeared simultaneously at 75-80 days of gestation. The response increased with age of the fetus until, by 120 days of gestation, the response to PHA, Con A and PWM of many fetuses was in the range of values obtained with lymphocytes from normal adult cattle.

Animals↗

PubMed1988

Identification of abdominal aortic aneurysm patients with different clinical features and clinical outcomes.

To determine the clinical characteristics and factors influencing outcome in patients with atherosclerotic abdominal aortic aneurysms (AAA), 526 patients who underwent aneurysmal resection were retrospectively reviewed: Group I had clinical evidence of atherosclerotic occlusive disease; Group II had no evidence of atherosclerotic occlusive disease. The incidence of ruptured AAA, multiple aneurysms, and a family history of AAA was higher in Group II patients. We concluded that patients with AAA and without atherosclerotic occlusive disease in other areas represent a subgroup with peculiar clinical characteristics. In planning operative treatment and during the follow-up period, it should be kept in mind that Group II patients have a higher incidence of aneurysm rupture; the incidence of late pseudoaneurysm is higher; and there is a greater possibility of aneurysm in other arterial segments. It remains to be seen if the pathogenetic mechanism of AAA formation in Group II patients is different from that in Group I patients.

Aged↗

PubMed1988

Early and late results in patients with carotid disease undergoing myocardial revascularization.

A ten-year review of 1,360 patients undergoing coronary artery bypass grafting (CABG) by the same surgeon was undertaken. Sixty-two patients with symptoms of coronary artery insufficiency underwent carotid endarterectomy prior to or at the time of CABG (Group I). Ninety-seven patients had asymptomatic carotid bruits but did not undergo carotid endarterectomy (Group II). Sixty of these patients were studied by ultrasonic duplex scanning or ocular pneumoplethysmography or both, and hemodynamically significant stenosis was detected in 50 (Group IIa). Group III included 80 patients without carotid artery disease matched with Group II for sex, age, and clinical status. Group IV consisted of 200 patients without carotid artery disease randomly selected from our series. Follow-up ranged from 3 to 120 months (median, 41 months). In patients with proven carotid artery disease (Groups I and IIa), operative mortality was greater than in the patients randomly selected (Group IV) (p less than 0.05) but similar to that in the matched Group III. Late neurological deficits were greater in patients with carotid disease not undergoing carotid endarterectomy (p less than 0.01). Patients with carotid artery disease had lower survival than Group IV patients (p less than 0.01) but similar survival to that in the matched Group III. This study suggests that (1) asymptomatic patients with carotid artery disease who undergo CABG are not at increased risk of perioperative stroke; (2) these same patients are at increased risk of late neurological deficit; and (3) carotid artery disease is an indirect sign of severe associated disease and therefore is associated with increased operative mortality and decreased life expectancy.

Adult↗

PubMed1988

External carotid endarterectomy: indications, technique, and late results.

In the past 14 years, 22 patients (25 operated sides), with occlusion of the internal carotid artery (ICA), underwent ipsilateral external carotid artery (ECA) endarterectomy at our institution. Operative indications were amaurosis fugax in 13 sides and nonlateralizing transient ischemic attacks in the remaining 12. There were no operative deaths. One patient suffered a minor stroke after operation. Follow-up ranged from 6 to 110 months (median 36 months). In 16 cases, simple endarterectomy with or without vein patch closure was performed (type I). In two cases the ostium of the ICA was occluded with interrupted sutures after endarterectomy (type II). In the remaining seven cases the ICA was transposed as a patch over the endarterectomized ECA after endarterectomy (type III). All but six patients (six sides) underwent duplex scanning or angiography during follow-up. Four of nine patients with previous nonlateralizing symptoms had persistent symptoms after operation, whereas none of those with previous amaurosis fugax did. Recurrent occlusive disease was more common in type I reconstructions (p less than 0.05). Proper ECA reconstruction results in long-term patency. In the patient with ipsilateral ICA occlusion, transposition of the ICA as a patch over the endarterectomized ECA offers a valid hemodynamic solution. Objective parameters are needed to identify patients with nonlateralizing symptoms who will benefit from operation.

Aged↗

PubMed1988

Seeding with endothelial cells derived from the microvessels of the omentum and from the jugular vein: a comparative study.

Segments of an experimental polytetrafluoroethylene graft (9 cm long, 6 mm I.D.) of high porosity were implanted in 25 dogs as aortic interposition grafts. Nine grafts were seeded with a mean of 7 x 10(5) viable endothelial cells (ECs) derived from the jugular vein (group A) and eight were seeded with a mean of 7 x 10(5) viable ECs derived from the microvessels of the omentum (group B). Eight grafts were not seeded and they served as controls (group C). Animals were put to death 5 weeks after graft implantation. The thrombus-free area was measured at 81% +/- 10% in group A, 65% +/- 22% in group B, and 25% +/- 13% in group C (p less than 0.05, group A vs group B; p less than 0.05, group B vs group C). The thickness of the subendothelial layer was 151 +/- 60 microns in group A, 280 +/- 60 microns in group B, and 100 +/- 75 microns in group C (p less than 0.001, group B vs groups A and C). The production of 6-keto-PGF1 alpha in the presence of sodium arachidonate was higher in seeded grafts (p less than 0.05). Omentally derived microvessel ECs can be seeded in vascular grafts; refinements in the technique of EC procurement are required to minimize contamination and to obtain ECs with more effective biologic activity.

6-Ketoprostaglandin F1 alpha↗

PubMed1988

Congenital abdominal aortic aneurysms in the young. Case report and review of the literature.

Aneurysms of the aorta are rare in children and young adults. We report a case of a 19-year-old man with a saccular abdominal aortic aneurysm (AAA). No associated disorders were discovered in this patient. The aneurysm was resected and a Dacron aortic graft was implanted. Nine years after operation the patient was in good health without evidence of other aneurysms. Thirty-two cases of probable congenital abdominal aortic aneurysms were collected from the literature. In 19 cases, the cause of aneurysm was not ascertained. We identified two groups of patients with probably congenital AAAs: type I congenital AAA, in which there is a generalized disorder of the arterial tissue and usually aneurysms are present in other areas and type II congenital AAA, in which there is a localized defect of the abdominal aorta, without aneurysms in other areas. We speculate that a congenital defect localized to the wall of the abdominal aorta was the cause of the aneurysm in this patient (type II congenital AAA).

Adult↗

PubMed1988

Asymptomatic carotid artery stenosis on the side contralateral to endarterectomy. A comparison between patients with and those without operation.

From May 1974 to October 1983, 82 patients with severe bilateral carotid disease had unilateral carotid endarterectomy (CE) on the symptomatic side (group I). The carotid artery contralateral to the endarterectomy was severely stenosed (lumen diameter reduction 51% up to 99%) and it was not repaired for different reasons. Group I patients were compared with 78 patients who had bilateral CE (group II), matched with group I for associated diseases, operative indication, and angiographic findings. In this analysis, only neurologic deficits referable to the contralateral hemisphere were considered. There was a higher incidence of later neurologic deficits in the group I patients; however, this difference was not statistically significant. In group I, the occurrence of late neurologic deficits was statistically correlated to (1) severity of stenosis, (2) presence of large compound ulceration, and (3) history of previous stroke. Stepwise logistic regression analysis identified two groups of patients at higher risk for late neurologic deficits (1) patients with stenosis 75% or greater and large ulceration and (2) patients with stenosis 75% or greater and previous stroke. CE on the asymptomatic contralateral side should be considered in selected patients at high risk for late neurologic events at a surgical center with an established low incidence of perioperative complications. A nonoperative policy with careful follow-up is warranted in the remaining cases.

Carotid Arteries↗

PubMed1988

Epidemiologic and immunologic evaluation of an outbreak of canine blastomycosis.

Five confirmed cases of canine blastomycosis occurred over the 10-month period of December 1983 to September 1984 in a south-eastern Wisconsin colony of 30 dogs maintained for sled competition. Contrary to other published reports of canine blastomycosis, the sex-specific attack rates were higher among females than males. Four of the five confirmed cases and all four deaths occurred among young female dogs. Differences in the age distribution and/or the micro-environment of the females may have contributed at least in part to the difference in sex-specific attack rates. The serologic response and leukocyte function of the clinically affected and apparently healthy dogs from this colony were assessed during the outbreak. A survey of the adult dogs in the colony suggested that the mitogen-induced lymphocyte blastogenesis of dogs with clinical signs of blastomycosis was suppressed compared with that of dogs that remained free of clinical signs. In contrast to previous reports that autologous sera from dogs and humans with clinical blastomycosis inhibited mitogen-induced lymphocyte blastogenesis, lymphocyte responsiveness was similar to, or greater in the presence of autologous canine serum than it was in the presence of fetal bovine serum.

Animals↗

PubMed1988

Ultrasonographic features of carotid plaque and the risk of subsequent neurologic deficits.

In a prospective study, 214 consecutive patients considered not to be candidates for surgical intervention were evaluated by means of duplex scanning. Of the patients, 135 had no symptoms and 79 had a history of previous neurologic symptoms. In 139 sides duplex scanning demonstrated nonhemodynamic stenosis (lumen diameter reduction, less than 50%) and in 99 sides, hemodynamic stenosis (lumen diameter reduction, 50% or greater). Of the 238 carotid artery plaques examined, 167 were homogenous and 71 were heterogenous. During a mean follow-up of 34 months, 27 new focal neurologic deficits occurred. Patients with previous symptoms had a higher incidence of new deficits (18/79 vs 9/135) (p less than 0.01). The severity of the stenosis and the presence of a heterogenous plaque were statistically correlated with the occurrence of new deficits (p less than 0.001). Multivariate analysis showed that the ultrasonographic pattern and the severity of the stenosis were independent variables. We conclude that a heterogenous plaque should be considered an unstable plaque with the possibility of causing cerebral ischemia.

Aged↗

PubMed1988

Carotid endarterectomy in octogenarians and nonagenarians.

Experience with carotid endarterectomy (CE) in patients 80 years of age and older is analyzed by reviewing results in terms of patient survival, quality of life and recurrence of symptoms of cerebral ischemia. During a 12 year period, 90 octogenarians underwent CE. Ages ranged from 80 to 93 years with a mean of 83 years. Two groups of patients younger than 80 years of age were selected from the series for comparison. There were no differences between age groups with respect to operative mortality and morbidity, with two deaths and one stroke in the elderly group. Follow-up periods ranged from one to 120 months with a mean of 39 months. There were two late strokes in patients older than 80 years of age. At late follow-up study, 87 per cent of patients operated upon for hemispheric symptoms were free of neurologic deficits; in contrast, only 67 per cent of those operated upon for nonhemispheric symptoms were symptom-free (p less than 0.05). The incidence of occlusive disease of the intracranial portion of the internal carotid artery was higher in the elderly group (p less than 0.01). The presence of intracranial occlusive disease represented an unfavorable factor in regard to the results of CE in patients with nonhemispheric symptoms. The over-all five year survival rate was 60 per cent. These data indicate that advanced age alone should not be considered a contraindication to CE. Excellent results should be expected in instances of operations performed for hemispheric symptoms. In instances of nonhemispheric symptoms, results are less encouraging because of the high incidence of intracranial carotid occlusive disease.

Actuarial Analysis↗

PubMed1987

Factors influencing enlargement rate of small abdominal aortic aneurysms.

The purpose of this study was to determine the factors influencing enlargement rate of small abdominal aortic aneurysms. Fifty-seven high-risk patients with asymptomatic abdominal aortic aneurysms initially measuring 3.5 to 5.9 cm in the largest transverse diameter were followed with serial echographic measurements for 6 to 78 months (mean 24). The mean enlargement rate (MER) and the occurrence of sudden change in size (SCS) for each aneurysm were correlated to 23 variables. MER ranged from 0 to 1.8 cm/year (mean 0.48). During the study period 17 aneurysms showed SCS. The results of univariate analysis indicated that 8 variables were statistically correlated to the degree of MER and 5 to the occurrence of SCS. A multiple regression model was generated by stepwise regression analysis and demonstrated that 2 variables were independent predictors of the degree of MER: (1) the absence of distal arterial occlusive disease and (2) the ratio of the diameter of the aneurysm to that of the aorta (RD). The overall model P value was less than 0.001. A statistically valid multiple regression model to predict the occurrence of SCS was not feasible (P = 1.0). We conclude that the occurrence of SCS of small abdominal aortic aneurysms is often unpredictable and that the RD rather than the value of the aneurysmal diameter per se must be considered in selecting high-risk patients for echographic follow-up.

Aged↗

PubMed1987

Isolation and characterization of porcine natural killer (NK) cells.

The morphologic and biological properties of porcine cells mediating natural killer (NK) activity were determined. In a previous study, we demonstrated that lymphocytes from the peripheral blood of pigs greater than 1 week of age possessed NK activity to K562 tumor cells and that lymphocytes from the blood and spleen of pigs greater than 1 day of age were able to mediate natural cytotoxicity against parainfluenza-3 (PI3) virus-infected Vero cells (Yang and Schultz, 1986a). Discontinuous density gradients were used to enrich NK cells. NK cytotoxicity was mainly present in high-density Percoll fractions (50 to 55% and 55 to 60%); little or no NK activity was present in lower density fractions. The NK cell enriched lymphocytes responded to the mitogens PHA, ConA and PWM. NK cells were sensitive to the suppressive effect of corticosteroid, but Protein A did not affect NK activity. The amount of cytotoxicity directly corresponded to the degree of binding that occurred between the NK enriched lymphocyte population and the target cells. Cytochemical and morphological studies demonstrated that these bond cells which are believed to be responsible for the NK activities, were mainly small to medium lymphocytes lacking azurophilic cytoplasmic granules. These findings were confirmed by ultrastructural studies of effector and "target-binding" cells. The results of the present study suggested that the cells mediating NK activity in pigs have the morphological and density characteristics of small and medium sized lymphocytes; findings that differ from those described for NK cells in human and other animal species.

Adrenal Cortex Hormones↗