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Biomedical subjects

D B Walsh

Publications and source records attributed to D B Walsh.

At least 55 records · Page 3Linked to original sources
PubMed1990

Variables that affect the expansion rate and outcome of small abdominal aortic aneurysms.

Seventy-three patients with small (less than 6 cm in diameter) abdominal aortic aneurysms (AAAs) were selected for nonoperative management and followed up with sequential ultrasound size measurements. Fifty-four men and 19 women, 51 to 89 years of age (mean 70 years), had an initial mean AAA size of 4.1 cm (anteroposterior) x 4.3 cm (lateral) diameter, with a calculated elliptic cross-sectional area of 14.3 cm2. After a mean of 37 months of follow-up, AAA area increased at a mean rate of 20% per year (3 cm2 yr; 0.4 to 0.5 cm/yr diameter). Expansion rate was not affected by initial aneurysm size. During follow-up, only 3 patients (4%) required urgent operation (1 died), 26 patients (36%) died of non-AAA causes, and 26 patients (36%) underwent elective AAA repair because of progressive size increase (1 died). Elective operations were performed at the rate of 10% per year, when mean AAA size had increased to 22 cm2 (5.1 cm in diameter). Multiple regression analysis of clinical parameters available at presentation indicated that subsequent elective AAA repair was predicted by younger age at diagnosis and larger initial aneurysm size. As anticipated, patients who underwent surgery had more rapid aneurysm expansion (5.3 cm2/yr) compared with patients who did not undergo surgery (1.6 cm2/yr; p less than 0.05). This difference was caused by more rapid expansion during later follow-up intervals among patients selected for operation and was not predicted by the change in aneurysm size observed during initial ultrasonographic follow-up. Final aneurysm size was predicted by initial size, duration of follow-up, and both systolic and diastolic pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1989

Limb salvage despite extensive tissue loss. Free tissue transfer combined with distal revascularization.

Extensive lower-extremity tissue loss may preclude limb salvage despite successful arterial reconstruction. We attempted to avoid limb loss in such patients by combining arterial bypass with microvascular free tissue transfer. Fourteen patient (12 diabetic), 33 to 74 years of age, presented with extensive tissue loss in 15 lower extremities, exposing bone or tendon on the heel, ankle, lower part of the leg, or hindfoot. Mean ulcer size was 5 X 8 cm. Four patients had had previous contralateral below-knee amputations. Femorodistal (seven), popliteal-distal (three), or femoropopliteal (four) bypass, or tibial angioplasty (one), was performed to provide sufficient inflow for free tissue transfer. Serratus anterior, scapular, latissimus dorsi, rectus abdominis, gracilis, ulnar, or temporalis free flaps were used. One free flap failed due to venous thrombosis and was corrected with a second flap. Limb salvage was achieved in 14 (93%) of 15 limbs during a mean follow-up of 24 months. The single amputation occurred due to severe foot ischemia in a patient whose femorodistal bypass remained patent only to the viable free flap. The remaining 13 patients (14 limbs) became ambulatory, including those with free flaps to weight-bearing regions.

Adult↗
PubMed1989

Effect of ampicillin-induced alterations in murine intestinal microbiota on the survival and competition of environmentally released pseudomonads.

The environmental release of genetically altered microorganisms has prompted the investigation of their potential health effects by the employment of other-than-human models. Although direct health effects are addressed, this investigation examines primarily some potential indirect health effects associated with environmentally released microorganisms. Indirect effects examined include colonization of the gastrointestinal tract, competition with the resident microbiota, and translocation of the dosed microorganisms to other organs. Pseudomonads used in this study were isolated from a commercial product marketed for environmental PCB degradation. When mice were dosed by gavage with approximately 10(9) ampicillin-resistant pseudomonads, an increase in recovery from the intestinal tract, as compared to untreated animals, was observed 48 hr after dosing. Intestinal survival of Pseudomonas aeruginosa strain BC16 was enhanced 1000-fold and that of P. maltophilia strain BC6, 10-fold. Strains BC17 and BC18 were unaffected. Ampicillin treatment had a significant effect on the relative number of microbiota in the intestine, by selecting primarily for the facultative species. The lactose-fermenting enterobacteria, obligately anaerobic predominantly Gram-negative rods, and total aerobic and anaerobic populations were monitored in the presence and absence of the PCB-degrading pseudomonad. P. aeruginosa strain BC17 and P. maltophilia strain BC6 had a dose effect (p less than 0.05) on the total aerobic and anaerobic populations as well as the lactose-fermenting enterobacteria. These results are similar to those for the mouse isolate control, strain PAMG. P. aeruginosa strain BC18 had a dose effect (p less than 0.05) on the total anaerobic population, including the obligately anaerobic Gram-negative bacilli. No translocation of the dosed strains to the liver, spleen, or lung was observed 48 hr after dosing.

Ampicillin↗
PubMed1989

Polychlorinated biphenyl-degrading pseudomonads: survival in mouse intestines and competition with normal flora.

Although naturally occurring and mutant organisms, historically, have been released into the environment for various purposes, health concerns associated with the release of microorganisms have recently resurfaced. Federal agencies have been given the task of reassuring society that any released organisms are not likely to produce adverse health effects. Methods, therefore, for evaluating the potential health effects due to environmental release of mutant and genetically engineered microorganisms are under investigation. A mouse model was developed that examines morbidity, mortality, and more indirect effects such as colonization potential of the intestinal tract, as well as competition with and alteration of the intestinal microbiota populations. The Pseudomonas spp. used in this study were isolated from a commercial product and used for degrading polychlorinated biphenyls. Mice were dosed individually with 10(3), 10(6), and 10(9) colony-forming units of each microorganism. At specific time intervals the intestines were removed and examined for the presence of the dosed microorganism. At the two higher doses, 10(6) and 10(9) colony-forming units, P. maltophilia strain BC6 and two P. aeruginosa strains, BC16 and BC18, were recoverable 48 h after dosing. The naturally occurring P. aeruginosa strain, PAMG, isolated from a mouse intestinal homogenate produced a similar response. Statistical analysis indicated that in some of the dosed animals, an alteration in the distribution of normal intestinal microflora occurred. Pseudomonas maltophilia strain BC6 and P. aeruginosa strains BC16 and BC17 caused a change in the obligately anaerobic predominantly gram-negative rod counts, and P. aeruginosa strain BC17 produced a dose effect on the total anaerobic count at the 10% confidence level. The total aerobic count was unaffected by the presence of the dosed pseudomonads.

Animals↗
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

Tibial artery pseudoaneurysms: delayed complication of balloon catheter embolectomy.

Although complications of balloon catheter embolectomy are infrequent, the injury potential of these catheters is well recognized. This article describes a case of multiple tibial artery pseudoaneurysms that appeared 4 years after embolectomy in a 42-year-old man with otherwise normal arteries. The patient was treated by internal aneurysmorrhaphy without sequelae. A literature review of balloon catheter injuries yielded 46 cases categorized as arterial disruption (29), intimal injury (12), or catheter malfunction (5). These resulted in hemorrhage (13 cases), arteriovenous fistula (12), pseudoaneurysm (four), thrombosis (three), dissection (five), accelerated atherosclerosis (four), and catheter fragment embolism (five). Of these complications, only 41% were recognized during the initial operation. Direct observation detected 32% of these, whereas 68% were shown only by completion arteriography. Complications recognized during initial operation were more frequently asymptomatic without further surgery (84%) than those detected postoperatively (30%, p less than 0.001). Completion arteriography detected 87% of balloon catheter complications compared with only 23% of complications recognized intraoperatively without arteriography (p less than 0.001). We conclude that delicate technique, completion arteriography, prompt surgical treatment, and extended follow-up are important components of balloon catheter embolectomy.

Adult↗
PubMed1987

Metastatic cancer. A relative contraindication to vena cava filter placement.

From October 1979 to November 1984, 41 patients underwent placement of vena cava filters for prevention of pulmonary emboli. After filter placement, no pulmonary emboli were documented. No patient died due to filter placement. However, 20 of these 41 patients are dead. Eighteen deaths were caused by cancer. Ten (24%) patients died within 2 months of filter placement. Five (12%) patients died prior to hospital discharge. All ten of these patients had known, widely metastatic cancer. Among the ten patients who died more than 2 months after filter placement, six had well-differentiated, slow growing tumors. Only three of these patients had brain metastases. Among the 21 survivors only two suffered from cancer. Strict adherence to accepted indications for vena cava filter placement required operative procedures on a small but significant number of patients who demonstrated no significant improvement in quality of life or time out of hospital. Filter placement in patients with aggressive cancers and proven metastases should be performed only after analysis of predicted survival and after detailed discussions with patients and referring physicians. Filter placement in patients with aggressive metastatic cancer may cause discomfort, risk, and expense with little hope for improvement of hospital course, longevity, or quality of life.

Adult↗
PubMed1987

Intraoperative single-dose radiotherapy. Observations on staging and interstitial treatment of unresectable liver metastases.

Fourteen patients with a history of colonic cancer were evaluated for metastatic disease and were thought to have unresectable disease confined to the liver. Exploratory surgery revealed that two patients had extensive extrahepatic disease, and the procedure was terminated. In 12 patients, closed-end needles (diameter, 2.1 mm) were introduced into each nodule and connected to a 370-MBq (10-Ci) afterloading iridium source. Radiation doses were dependent on nodule size, providing minimum doses of 20 Gy (2000 rad) to the lesion's periphery with rapid radiation falloff avoiding toxic effects to adjacent normal tissue. The maximum number of nodules treated in one patient was 11. The largest nodule treated measured 9 x 6.5 x 6 cm. Cholecystectomy in four patients allowed precise implantation and obviated biliary fistula. Preoperative computed tomography underestimated the number of hepatic metastases in all cases but one, and treatment-induced computed tomographic alterations further limited its utility. Radiation treatment was well tolerated, and the median hospitalization was eight days. Of ten patients whose preoperative carcinoembryonic antigen values exceeded 10 ng/dL, the values in six patients decreased postoperatively.

Adult↗
PubMed1987

Valvular obstruction of blood flow through saphenous veins.

To measure effects of vein valves upon blood flow through venous bypass conduits, 15 human saphenous veins (mean length 40.6 cm, 5.3 valves/vein) were perfused with normal saline at constant pressure (100 mm Hg). Flow through vein was measured before and after valve bisection. Vein valves were bisected using Leather's techniques. After valve bisection, flow in antegrade and retrograde directions was measured in seven veins. These data were analyzed using paired t tests. Antegrade flow through seven veins with intact valves averaged 317.1 cc/min. With valve bisection this increased significantly (P less than 0.001) to 474.3 cc/min. Retrograde flow through veins with valves bisected increased significantly (P less than 0.0001) to 428.3 cc/min. Eleven veins (mean length 42.2 cm, 5.6 valves/vein) perfused simulated capillary beds with banked blood using pulsatile flow (mean pressure 92 mm Hg). Flow, again, was measured before and after valve bisection. Data were analyzed using the paired t test. Antegrade flow increased from 124.4 cc/min in veins with valves intact to 142.5 cc/min once valves were bisected (P = 0.02). These data demonstrate that saphenous vein valves cause significant obstruction to blood flow under conditions similar to those in the arterial system. Bisection of vein valves significantly increases flow through vein. Improved patency of vein grafts using valve bisection techniques may be explained by increased blood flow alone.

Blood Flow Velocity↗
PubMed1987

Computer-assisted structure-activity relationships of nitrogenous cyclic compounds tested in salmonella assays for mutagenicity.

Study of the relationship between mutagenicity and molecular structure for a data set of nitrogenous cyclic compounds is reported. A computerized SAR system (ADAPT) was utilized to classify a data set of 114 nitrogenous cyclic compounds with 19 molecular descriptors. All of the descriptors represented at least 10% of the compounds in the data sets. The average correct predictability of the data base was calculated to be 89% after evaluating 100 training/prediction subsets. The actual predictive ability of the discriminants generated by the ADAPT system was demonstrated by predicting the mutagenicity of structurally similar compounds not in the data set. Weight vectors generated in the pattern recognition programs were used to predict the bacterial mutagenicity of 10 compounds which were not included in the data set. All of the compounds were predicted correctly which was actually better than the 89% calculated by the system. This displayed the ability of the system of classify compounds as mutagenic or nonmutagenic by using molecular descriptors and to predict the biological activity of untested chemicals with a high degree of confidence. This paper presents the uses of this type of SAR approach in a research laboratory.

Heterocyclic Compounds↗
PubMed1986

Crohn's appendicitis in an incarcerated spigelian hernia.

A patient with incarcerated Crohn's appendicitis and a spigelian hernia is presented, representing the challenge in diagnosis, incision choice, and choice of definitive surgical procedure. While it is unlikely that the report of such a patient's course will make prospective recognition of this rare entity more likely, a systematic approach to this patient has allowed a satisfactory result with minimal complications.

Adult↗
PubMed1986

Previously unreported abnormalities of dermal basement membranes and collagen fibrils in a patient with X-linked spondyloepiphyseal dysplasia tarda.

Electron microscopic findings of the skin biopsy of a boy with spondyloepiphyseal dysplasia tarda showed several novel features. The basement membrane of the epidermis showed focal irregular thickening and reduplication. The collagen fibres showed foci of fibrous long spacing collagen and marked variation in fibre diameter. Taken together these abnormalities have not been reported in any other condition.

Adolescent↗
PubMed1985

Routine endoscopy of the upper gastrointestinal tract in the evaluation of obstructive jaundice.

Our experience with flexible end-viewing EGD in the patient with jaundice demonstrated an over-all low specificity (19 per cent) for clinically significant lesions in this patient population. The discovery of synchronous lesions of the upper gastrointestinal tract in 12 patients did not change our diagnostic or therapeutic planning. Therefore, we believe that there is little justification for the increased costs and patient discomfort involved in routine EGD which should be abandoned in instances of obstructive jaundice and should be used only when more specific indications for its use are present.

Adult↗
PubMed1984

In vitro observations of greater saphenous vein valves during pulsatile and nonpulsatile flow and following lysis.

A significant number of saphenous vein femoral-popliteal bypass graft failures have been attributed to flow abnormalities caused by venous valves. Seventy-seven greater saphenous vein valves were observed and photographed through a 0-degree choledochoscope during pulsatile and nonpulsatile flow. No valve was seen to lie flat against the vein wall. With pulsatile flow the valves were noted to close during diastole. Stasis was noted within the valve cusps. Twenty-three valves produced photographs of sufficient quality to allow measurement of the luminal obstruction caused by the valves. This valvular obstruction represented 61% +/- 12% of the total vein lumen. Fifty venous valves were lysed by five different techniques: the microscissors, the Connolly vein stripper, the Mills valvulotome, the venotomy valvulectomy of Hall, and eversion valvulectomy. The first three methods created valvular incompetence, but flaps of valve cusps were observed to disturb flow and place potentially thrombogenic surfaces within the vein lumen. Valvulectomy, whether by venotomy or eversion, removed the valve cusps satisfactorily.

Blood Vessel Prosthesis↗
PubMed1982

Adenocarcinoma of the ampulla of Vater. Diagnosis and treatment.

Fifty-one patients underwent operation for adenocarcinoma of the ampulla of Vater. Seven patients underwent palliative bypass, with an operative mortality of 28.6%; 44 additional patients underwent potentially curative pancreaticoduodenal resection (PDR), with an operative mortality of 15.9%. Postoperative complications occurred in 63% of patients. Postoperative gastrointestinal bleeding was observed in 11 of 44 patients who underwent PDR (25%). Although anastomotic ulcers (AU) were directly implicated in five cases (45%), the 12% incidence of AU-related bleeding among 33 patients who underwent PDR without truncal vagotomy (TV) was not significantly different from the 9% incidence observed in 11 patients who underwent PDR plus TV. However, performance of TV appeared to result in a higher incidence of postoperative pulmonary complications. Five patients who underwent curative resection survived for five years (11%). Only one of seven patients who underwent palliative bypass survived three years (14%), and none survived to five years. Acceptable survival rates following resectional therapy warrant an aggressive approach to this tumor. Further, our experience suggests that TV may increase postoperative patient morbidity without actually providing any protection from anastomotic ulceration.

Adenocarcinoma↗
PubMed1982

Risk associated with diabetes mellitus in patients undergoing gallbladder surgery.

Diabetes mellitus has been suggested as a risk factor in patients undergoing gallbladder surgery. To assess the validity of this observation, a study of 175 diabetic and nondiabetic patients who underwent cholecystectomy of cholecystostomy was undertaken. Eighty patients (40%) were diabetic, and 95 (54%) were nondiabetic. The rates of death and complications were nearly identical in both diabetic and nondiabetic populations. In this selected population renal disease and vascular occlusive disease (with or without diabetes mellitus) resulted in a significant (P less than 0.01) increase in morbidity and mortality rates. Therefore, we conclude that diabetes mellitus alone does not appear to adversely affect the prognosis of patients who require gallbladder surgery.

Acute Disease↗