Search PubMed⌕ Search

Biomedical subjects

M D McDaniel

Publications and source records attributed to M D McDaniel.

32 records · Page 2Linked to original sources
PubMed1989

Great expectations: stress and the medical family. 1987 Committee on Issues, Association for Academic Surgery.

The high divorce rate and significant stress experienced by families of academic surgeons stimulated the Committee on Issues of the Association of Academic Surgery to choose medical family stress as the topic for the 1987 Committee presentation at the annual meeting. The Committee hoped to provide insight into the cause of this stress and new strategies for coping with this pervasive problem. Forty-three percent of the 505 surgeons who entered the Association from 1981 through 1984 and 38% of their spouses responded to a questionnaire covering issues of time management, response to stress, child rearing, financial security, and spouse career. A panel consisting of Shirley P. Levine, M.D., Hiram C. Polk, Jr., M.D., and Lane A. Gerber, Ph.D., after discussing the questionnaire results, recommended realistic goal setting, specific prioritization of activities, recognition of the considerable contributions of the spouse, and insight into personal limitations as mechanisms for improving family function.

Female↗
PubMed1988

Cost-effectiveness of intra-arterial thrombolytic therapy.

We reviewed the clinical course of 23 patients who received 24 intra-arterial infusions of either streptokinase or urokinase to treat 14 arteries and ten arterial grafts that were occluded due to primary thrombosis (22) or artery-artery embolism (two). Time from symptom onset to treatment was one to 28 days (mean, 11 days). Five infusions (21%) were completely successful since symptoms were eliminated without subsequent operation. Seven infusions (29%) were partially successful since thrombolysis aided, limited, or postponed subsequent surgery. Six infusions (25%) were failures since thrombolysis or clinical improvement did not occur and surgery was required. Six infusions (25%) were associated with thrombolytic complications that required urgent operation (less severe complications occurred in an additional 17% of cases [4/24]). Of the 19 patients without complete success after thrombolytic therapy, 16 underwent surgery during the same admission, two were not operable due to distal disease, and one declined operation. Of the 16 operations, 15 (94%) were successful in restoring graft or artery patency and achieving limb salvage, whereas one failed. In the 12 patients with failure or major complications of thrombolytic treatment, all had successful surgical outcome without morbidity. The actual mean cost of thrombolytic treatment was $8200 per patient and was comparable with the actual mean cost of subsequent surgical treatment in the 16 patients who required operation ($8900 per patient). The effective cost of thrombolytic and surgical treatment was calculated by dividing the actual costs by the proportion of successful cases. The effective cost of thrombolytic therapy per complete success was $39,200 and per complete or partial success was $16,500. This was significantly more than the effective cost of $9400 per complete success of surgical therapy.

Adult↗
PubMed1988

Efficacy of muscle flaps in the treatment of prosthetic vascular graft infections.

Prosthetic vascular graft infection requires graft removal and often leads to limb loss. To determine whether vascularized muscle flaps could alter the course of graft infection, 18 mongrel dogs (18-29 kg) were randomized to one of three groups and underwent unilateral carotid artery bypass with 6-mm X 4-cm PTFE grafts. At implantation, the grafts were inoculated with Staphylococcus aureus, 2 x 10(7) organisms/wound. On Day 3, dogs with patent grafts underwent wound debridement, irrigation, and closure, and the treatment to which they had been randomized was carried out. Group A (n = 4, controls) received only dicloxacillin, 500 mg po bid, beginning on Day 4. Group B (n = 5) underwent transfer of a vascularized sternocephalicus muscle flap around the infected graft, but received no antibiotics. Group C (n = 5) underwent muscle transfer as in Group B and were given dicloxacillin as in Group A. Dogs were followed until anastomotic disruption occurred or for 60 days. Quantitative bacterial cultures were taken from sternocephalicus muscle and wound fluid at the time of debridement and at sacrifice. All dogs that received antibiotics without flaps or flaps without antibiotics (Groups A and B) experienced anastomotic disruption. Dogs that received both antibiotics and flaps (Group C) had a significantly lower incidence of hemorrhage (20%, P less than 0.05). At sacrifice, fewer bacterial colonies were cultured from muscle flaps of Group C as opposed to Group A dogs (0.05 +/- 0.02 x 10(5) vs 0.79 +/- 0.31 x 10(5), P less than 0.05). Muscle flaps with antibiotic therapy may prove to be effective treatment for infected prosthetic vascular grafts.

Animals↗
PubMed1987

Effect of a selective thromboxane synthase inhibitor on arterial graft patency and platelet deposition in dogs.

This study examined the effect of selective thromboxane synthase inhibition and nonselective cyclooxygenase inhibition on vascular graft patency and indium 111-labeled platelet deposition in 35 mongrel dogs undergoing carotid artery replacement with 4 mm X 4 cm polytetrafluoroethylene (PTFE) (one side) and Dacron (opposite side) end-to-end grafts. Aspirin-dipyridamole therapy improved one-week graft patency, from 46% in untreated dogs to 93% in treated dogs. Thromboxane synthase inhibition (U-63557A) improved graft patency in these dogs to 81%. Both drug treatments reduced platelet deposition on Dacron and PTFE grafts by 48% to 68% compared with control dogs. Dacron grafts accumulated significantly more platelets than PTFE grafts but had comparable patency rates. Low-dose aspirin therapy had no significant effect on either graft patency or platelet deposition. All treatment groups showed a 60% to 76% reduction in serum thromboxane B2, but only thromboxane synthase inhibitor treatment increased plasma 6-keto-prostaglandin F1 alpha by 100%. Selective thromboxane synthase inhibition improved small-caliber prosthetic graft patency to the same extent as did conventional cyclooxygenase inhibition in this preliminary study.

6-Ketoprostaglandin F1 alpha↗
PubMed1987

Two-dimensional ultrasonic tissue characterization: backscatter power, endocardial wall motion, and their phase relationship for normal, ischemic, and infarcted myocardium.

To understand the possible differences in reflected ultrasonic energy from normal, ischemic, and infarcted myocardium, we studied 20 open-chest dogs with a commercially available two-dimensional ultrasonic scanner. Echocardiographic radiofrequency images of anterior myocardium were obtained serially during complete coronary occlusion for 2 hr (n = 15) or 5 hr (n = 10), or after temporary coronary clamping for 15 min with release for 1 hr (n = 5). We investigated two variables: the cyclic backscatter power and the phase difference among endocardial wall motion (EWM), cyclic backscatter power (BSP), and left ventricular pressure (LVP). The cyclic BSP decreased from a control (nonischemic) level of 5.1 +/- 0.8 to 2.3 +/- 0.7 dB during ischemia (up to 30 min after coronary ligation). The phase difference between the EWM and BSP progressed from a control (nonischemic) value of 38 +/- 20 to 115 +/- 23 degrees during ischemia. For the infarction period (2 to 5 hr after coronary ligation), the cyclic BSP progressively returned toward baseline control levels to 4.0 +/- 1.2 dB, but the phase had increased further to 170 +/- 28 degrees. The reperfusion study showed a similar decrease in cyclic BSP and an increase in phase after arterial clamping and both returned to near-normal nonischemic values upon arterial release. Simultaneous LVP recordings were performed to assess the phase contribution of endocardial dyskinesis to the total phase difference measurement. At 5 hr the dyskinesis had contributed 46% to the total phase difference, while the backscatter power contributed 54%. However, the EWM contribution occurred immediately while BSP contribution changed progressively during the 5 hr study period.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Efficacy of silver sulfadiazine in the treatment of prosthetic arterial bypass graft infection.

Infection is an uncommon but unfortunate complication of prosthetic arterial bypass grafting. Because previously described methods of treatment of such infections which do not involve excision of the graft have not met with uniform success, we undertook a study of the efficacy of silver sulfadiazine cream in the treatment of Staphylococcus aureus infections of polytetrafluoroethylene carotid artery bypass grafts in dogs. At the time of bilateral grafts placement in 14 dogs, wounds were inoculated with at least 2 X 10(7) organisms. Three days later all wounds were opened. The wounds of seven dogs were treated with daily applications of silver sulfadiazine cream and the wounds of the other dogs were treated with daily applications of povidone iodine ointment. The dogs were sacrificed at 30 days or at the earliest evidence of arterial beeding from the wounds, whichever came first. Cultures of the wound were taken, and graft and artery histologic findings were studied at the time of sacrifice. Although survival of the dogs treated with silver sulfadiazine was marginally better than that of the dogs treated with povidone iodine, viable bacteria were present in microabscesses in many apparently healed wounds in the former group. We conclude that daily applications of silver sulfadiazine cream does not reliably eradicate staphylococcal infections involving polytetrafluoroethylene arterial bypass grafts.

Abscess↗
PubMed1984

Sequential changes in coagulation and platelet function following femorotibial bypass.

Twenty-four patients who received no antiplatelet medications and underwent femorotibial bypass grafting (nine vein, 12 polytetrafluoroethylene [PTFE], and three composite PTFE-vein) had serial measurements taken of their platelet function and coagulation. The concentration of collagen required to produce half-maximal platelet aggregation (Kd), the platelet aggregation ratio, antithrombin III, factor VIII-related antigen, and fibrinolytic activity (platelet-rich plasma) was measured preoperatively and 3 and 7 days after surgery. Before surgery eight patients exhibited an increase of platelet reactivity to collagen. Following femorotibial bypass grafting, the mean preoperative Kd of 0.52 +/- 0.37 microgram/ml fell to 0.34 +/- 0.35 microgram/ml on the third postoperative day (P less than 0.001) and returned to 0.41 +/- 0.72 microgram/ml on day 7. Factor VIII-related antigen increased from a mean preoperative value of 248 +/- 29% of normal activity to a mean of 360 +/- 96% on postoperative day 3 (p less than 0.01) and further increased to 428 +/- 78% on day 7 (p less than 0.01). Fourteen patients had antithrombin III measurements taken, and their levels also fell on the third postoperative day (110 +/- 5.7% to 71 +/- 6.5%; p less than 0.001). No significant changes in fibrinolytic activity were noted. Persistent platelet reactivity was found in seven patients beyond the seventh postoperative day. After administration of 325 mg of aspirin, the abnormal platelet reactivity ceased. Increased platelet reactivity to collagen, factor VIII-related antigen, and a decrease in the antithrombin III level are indicative of a hypercoagulable state in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens↗
PubMed1984

Composite sequential grafts in severe ischemia: a comparative study.

From October 1978 to June 1983, 64 sequential bypass grafts were performed in 59 patients with limb-threatening ischemia. These patients were classified into three study groups as follows: reversed saphenous vein graft alone (12), composite sequential (proximal polytetrafluoroethylene [PTFE] and distal vein) graft (30), and PTFE graft in entirety (22). Graft patency was confirmed in all cases by serial Doppler ankle pressure measurements or by angiography. Cumulative life-table patency rates were then compared over a period of 27 months. The patency rates for composite sequential grafts using a distal short segment of vein were statistically indistinguishable from those for bypasses performed entirely with saphenous vein. These yielded a patency rate of 80% at 1 and 2 years. In contrast, the 1- and 2-year patency rates of the PTFE sequential grafts were 52% and 47%, respectively (p less than 0.05). Composite sequential bypasses using an otherwise inadequate segment of saphenous vein are a sound alternative revascularization procedure, with a patency rate comparable to that of reversed saphenous vein bypasses.

Adult↗
PubMed1984

Antithrombin III deficiency as a reflection of dynamic protein metabolism in patients undergoing vascular reconstruction.

Antithrombin III (AT-III) deficiency has been associated with increased risk of venous and arterial thromboses and arterial graft failure. Deficiency of this circulating glycoprotein may be congenital; however, acquired deficiencies may develop in protein-losing or protein-wasting states. In the present study, AT-III levels of 108 patients undergoing vascular surgical procedures were determined preoperatively and at intervals (third, fifth, and seventh days) postoperatively. The mean AT-III level was then compared to the patient's protein status. The effect of reduced AT-III activity on early graft failure was also noted. A low preoperative AT-III level (less than 80%) was found in 16.3% of the patients studied. Among 83 patients with serum albumin levels greater than 3.0 gm/dl or transferrin levels greater than 180 mg/dl, reduced AT-III activity was present in only 10 (12%). In contrast, when serum albumin levels were less than 3.0 gm/dl, AT-III deficiency was found in 12 of 25 patients (48%) (p less than 0.01). Early thrombosis of a femorodistal graft occurred in 5 of 15 patients (33%) with reduced AT-III levels. When AT-III levels were normal, early bypass failure occurred in only 9 of 67 grafts (13.4%). However, this difference was not statistically significant. An additional 15 patients had sequential pre- and postoperative measurements (up to 3 weeks) of serum protein and AT-III levels to illustrate the relationship between the dynamics of protein metabolism and AT-III levels. There was a clear temporal relationship between albumin, transferrin, and AT-III levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMedDate not supplied

Interventionalists' guide to the patient's experience of lower extremity arterial occlusive disease.

This article is intended as a guide for all who propose to intervene in patients with symptomatic lower extremity arterial occlusive disease. It reviews the natural history of and therapies for intermittent claudication. The results of a survey of claudicants are summarized; this survey gathered data on claudicants' general health, comorbid conditions, symptoms of claudication, and functional abilities. Respondents predicted a 20% improvement in their ability to perform instrumental activities of daily living (eg, walking several blocks, climbing one flight of stairs, performing household tasks) if lower extremity symptoms were relieved. This level of improvement is consistent with that reported in the literature following revascularization. The conclusion is that patients with claudication have modest goals with respect to improvement following vascular intervention. More data should be collected on the functional outcomes of vascular intervention so that patients can make better informed choices regarding treatment of symptomatic lower extremity arterial occlusive disease.

Activities of Daily Living↗
PubMedDate not supplied

Comparison of marginal adaptation between direct and indirect composites.

The evaluation of composite resin as a posterior restorative material has been slow and attended by several problems. Gap formation has been considered a serious problem by many researchers. The purpose of this in vitro study is to compare the marginal adaptation of posterior composite resins placed by a direct method with those placed by an indirect method utilizing flexible dyes. Conclusions drawn from the results of this study are that both techniques produced marginal gaps. Also there were no differences in the width of marginal gaps in the composite resin restorations placed by our direct or indirect methods, and no marginal gap differences were observed as a result of anatomical location.

Analysis of Variance↗