Biomedical subjects

J L Cohen

Publications and source records attributed to J L Cohen.

At least 19 recordsLinked to original sources

PubMed1992

Carotid endarterectomy in the elderly.

The records of 146 patients 80 years of age or older who underwent 183 carotid endarterectomy operations from 1964 through 1990 were reviewed to determine surgical risk. The indications for operation were asymptomatic patients with carotid stenosis (n = 36); ipsilateral transient ischemic attacks (n = 46); ipsilateral stroke (n = 28); ipsilateral retinal embolus (n = 15); nonlateralizing symptoms (n = 40); and asymptomatic side in patients with contralateral symptoms (n = 18). Postoperatively, three patients (1.6% of operations) had a stroke with a residual deficit and three (1.6%) died. All deaths were from myocardial infarction. For comparison, during the same time period, the combined stroke with residual deficit and death rate for patients less than 80 operated upon for similar indications was 3.5%. Since 80-year-old patients have a life expectancy of at least five years, the authors conclude that elderly patients should be evaluated for carotid endarterectomy using criteria similar to that used for younger patients.

Age Factors↗

PubMed1992

Early results of infrainguinal arterial reconstruction with a modified biological conduit.

We implanted 112 glutaraldehyde-fixed bovine carotid artery grafts (BioPolyMeric [BPM]) for infrainguinal reconstruction in 107 legs of 98 patients. Indications for surgery were disabling claudication in 28%, rest pain in 33% and tissue loss in 39%. In 32%, BPM bypass followed failed ipsilateral reconstruction. Autologous vein was either absent or inadequate in 60% of cases. BPM was used preferentially over vein in above-knee bypasses. The distal anastomosis was to the above-knee popliteal artery in 40%, to the below-knee popliteal artery in 35%, and to the tibial arteries in 25%. Follow-up was available from one to 25 months, with a mean of nine months. Wound complications developed after 9% of operations, including seven (6%) graft infections. Both patent grafts that became infected were salvaged. Four patients (4%) died within 60 days of surgery due to cardiac complications. Life-table primary and secondary patencies of all grafts were 64% and 65% at one year, and 48% and 62% at two years, respectively. The only factor significantly affecting graft patency was the location of the distal anastomosis (p < .01). Primary patencies at one and two years to the above-knee popliteal artery were 90% and 80%, to the below-knee popliteal artery were 56% and 37%, and to the infrapopliteal arteries were 34% and 26%. Bypass to 16% of extremities resulted in amputation, including 5% that were amputated with patent grafts. No limb loss occurred as a result of operation for claudication. In conclusion, BPM grafts provide early results comparable to saphenous vein above the knee.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1992

Vascular complications of the intra-aortic balloon pump.

The lower extremity complications of 100 consecutive patients who required the placement of an intra-aortic balloon pump (IABP) during a 3-year period were studied. Indications for the IABP included hypotension during cardiac catheterization (33%) or coronary angioplasty (13%), hemodynamic instability after open heart surgery (35%), unstable angina (5%), and cardiac arrest (14%). The incidence of IABP morbidity was 29%. Complications included ischemia (25%), bleeding (2%), lymph fistula (1%), and femoral neuropathy (1%). Twenty patients required 1 or more surgical interventions for lower extremity vascular complications. The majority of patients who underwent operation (70%) had significant pre-existing arterial occlusive disease. Local femoral artery reconstruction or repair was performed in 18 patients. Two patients had adjunctive bypasses. Continued IABP support was required in four patients after treatment of complications. One patient (1%) had an above-knee amputation. Limb ischemia was treated nonoperatively by removal of the IABP in five patients. Color-flow duplex scans were useful in distinguishing hematomas from pseudoaneurysms as well as for assessing femoral artery flow. We conclude that: (1) limb ischemia remains the primary complication of the IABP; (2) pre-insertion documentation of the severity of existing peripheral arterial disease by noninvasive studies may aid in the management of subsequent acute limb ischemia; (3) femoral artery thrombectomy or endarterectomy is usually sufficient for revascularization; and (4) noninvasive color flow studies are an important diagnostic tool in the nonoperative management of limb complications.

Adult↗

PubMed1992

Open-label study of the safety and efficacy of Fungoid tincture in patients with distal subungual onychomycosis of the toes.

Onychomycosis is the most frequent cause of nail diseases. An open-label study has been conducted to evaluate the safety and efficacy of Fungoid Tincture, a topical antifungal agent approved by the Food and Drug Administration for the treatment of onychomycosis of the toes. Ten patients with culture-proven distal subungual onychomycosis were treated twice daily for twelve months with topical Fungoid Tincture. Another ten patients with the same condition were treated with the vehicle alone. At monthly intervals, the target nail was trimmed, the nail bed debrided, and global clinical assessment recorded. After twelve months of therapy, all patients applying Fungoid Tincture showed negative findings on fungal culture. The vehicle alone benefitted several patients, and may have antifungal activity. Adverse effects were minimal, with mild peeling occurring in seven patients and erythema noted in one.

Antifungal Agents↗

PubMed1992

Acute mesenteric ischemia caused by isolated superior mesenteric artery dissection.

Isolated dissection of a peripheral artery is a rare event. Only 11 reports exist in the literature of dissection of the superior mesenteric artery, most of which have been fatal. This is the first documented case of the successful treatment of an acute ischemic event caused by a superior mesenteric artery dissection. In addition, the new technique of right gastroepiploic artery-to-superior mesenteric artery bypass is introduced as a satisfactory method of revascularization.

Acute Disease↗

PubMed1991

Dobutamine digital echocardiography for detecting coronary artery disease.

To assess the value of dobutamine echocardiography for detecting coronary artery disease (CAD), 70 men (mean age 62 +/- 8 years) presenting for coronary angiography were prospectively studied. Dobutamine (2.5 to 40 micrograms/kg/min) was infused in 3-minute stages. Digital echocardiograms were recorded on-line at baseline, during low- and high-dose dobutamine infusion, and at recovery. An echocardiogram positive for CAD was defined as one showing a new wall motion abnormality induced by dobutamine. Compared with coronary angiography, the overall sensitivity of dobutamine echocardiography for detecting CAD was 86%, specificity 95% and accuracy 89%. The sensitivity for detecting 3-vessel CAD was 100%, 89% for 2-vessel and 69% for 1-vessel CAD. The accuracy of predicting multivessel disease by 2 methods was 71% and 84%, respectively. Heart rate at the echocardiographic ischemic threshold was lower in patients with 3- and 2-vessel CAD versus 1-vessel CAD (89 +/- 17, 95 +/- 18 and 118 +/- 18 beats/min, respectively, p less than 0.01); rate-pressure product was also lower in patients with 3- and 2-vessel CAD versus 1-vessel CAD (12.7 +/- 3.6, 13.7 +/- 2.8 and 18.9 +/- 44 x 10(3) beats/min x mm Hg, respectively, p less than 0.01). Heart rate was the most important physiologic determinant of ischemia induced by dobutamine. There were no major complications during the study. Thus, dobutamine digital echocardiography is an excellent test for identifying CAD and should be beneficial in patients unable to exercise.

Adult↗

PubMed1991

Late results of small untreated abdominal aortic aneurysms.

We report our experience with 73 patients who were initially selected for nonoperative management of an abdominal aortic aneurysm less than 5 cm in diameter. Size of the aneurysm was determined by ultrasound (34); arteriography (16); computerized tomography (17); plain x-ray (4); and magnetic resonance imaging (2). End points of the study were subsequent elective resection, rupture, death from cause other than rupture, or an intact aneurysm followed for a minimum of three years. Overall, 28 (38%) aneurysms were subsequently resected on an elective basis; four (5%) ruptured; 15 (21%) were intact at the time of the patient's death; and 26 (36%) remained intact during follow-up of 3 to 6.5 years. Indications for elective resection were aneurysm enlargement (21); symptoms suggesting impending rupture (3); and improvement in medical condition (4). In the 43 aneurysms initially less than 4 cm diameter, 16 (37%) had elective resection and one (2%) ruptured, and in the 30 that were 4-4.9 cm, 12 (40%) were resected and three (10%) ruptured. The four aneurysms that ruptured had enlarged to greater than 5 cm prior to rupture. We conclude that aneurysms less than 4 cm can be safely followed. Aneurysms 4-4.9 cm should be considered for operation, depending upon the size of the aneurysm, patient's life expectancy, and risk factors for surgery. Any aneurysm that enlarges should be resected, especially if the aneurysm becomes larger than 5 cm in diameter.

Aged↗

PubMed1991

The diminishing role of diagnostic arteriography in carotid artery disease: duplex scanning as definitive preoperative study.

In an effort to eliminate the inherent neurologic morbidity associated with arteriographic investigation, we have increasingly relied upon duplex scans of the extracranial carotid arteries prior to endarterectomy. The percentage of patients undergoing carotid endarterectomy without arteriograms has increased from 5% in 1984 to 69% during 1988-1989. Initially, carotid endarterectomy without arteriography was limited to patients with hemispheric symptoms and relative contraindications. Over the course of the study from 1984-1989, indications for operation were similar for patients having carotid endarterectomy on the basis of duplex scan alone or following arteriography. The perioperative outcome for these patients undergoing duplex scan (n = 255) and arteriography (n = 484) were similar for stroke (2.4%) versus 2.7%, p = NS) and death (0% versus 0.4%, p = NS). Stratification of groups by indication did not show any significant differences in outcome. Duplex scans were sufficiently accurate to replace preoperative arteriograms in identifying significant stenoses at the carotid bifurcation, including asymptomatic disease. Lack of information regarding intracranial arterial occlusive disease did not adversely affect perioperative outcome. Carotid arteriography can be used selectively when duplex scans are technically difficult, when physical examination or scans suggest either inflow (arch) disease or diffuse, distal internal carotid plaque, or when cerebral symptoms are not sufficiently explained by duplex findings.

Aged↗

PubMed1991

Nail disorders in children.

The spectrum of nail abnormalities that may be seen in the pediatric population is discussed in this article. Developmental abnormalities, both hereditary and congenital, are discussed. Acquired nail abnormalities that may be similar to those seen in adults are also described.

Adolescent↗

PubMed1991

Congenital malalignment of the great toenails.

Congenital malalignment of the great toenails is a disorder in which malalignment of the nail matrix results in angular lateral nail plate growth. The consequence is onychodystrophy, which may progress to onychogryphosis and chronic ingrown toenails. There has been debate as to whether the condition is inherited or acquired in utero secondary to improper fetal positioning. A 6-year-old boy and his father, both of whom have this disorder, are discussed.

Child↗

PubMed1991

Pharmacokinetics of cefotaxime and desacetylcefotaxime in patients with liver disease.

The dispositions of cefotaxime and its metabolite desacetylcefotaxime were investigated in patients with different forms of chronic parenchymal liver disease (CPLD). A total of 31 subjects (27 patients and 4 controls) received a single 2-g dose of cefotaxime by infusion, and serial blood samples were drawn. The area under the concentration-time curve ranged from 176 to 241 micrograms.h/ml, the apparent half-life ranged from 1.49 to 2.42 h, and clearance ranged from 2.06 to 3.10 ml/min/kg in patients with four different forms of CPLD. The area under the concentration-time curve and the apparent half-life of desacetylcefotaxime ranged from 72 to 128 micrograms.h/ml and 7.1 to 13.4 h, respectively. Pharmacokinetic parameters were significantly different in patients with CPLD compared with those in control subjects and were related to clinical indices of hepatic impairment. Modest accumulation of cefotaxime in patients with severe hepatic impairment is unlikely to produce toxicity because of its high therapeutic index, and dosing modifications may not be required.

Adult↗

PubMed1991

A novel membrane-bound glucosyltransferase from Bradyrhizobium japonicum.

Bacteria within the family Rhizobiaceae are distinguished by their ability to infect higher plants. The cell envelope carbohydrates of these bacteria are believed to be involved in the plant infection process. One class of cell envelope carbohydrate, the cyclic beta-1,2-glucans, is synthesized by species within two genera of this family, Agrobacterium and Rhizobium. In contrast, species of the genus Bradyrhizobium, a third genus within this family, appear to lack the capacity for cyclic beta-1,2-glucan biosynthesis. Instead, these bacteria synthesize cyclic glucans containing beta-1,6 and beta-1,3 glycosidic linkages (K.J. Miller, R.S. Gore, R. Johnson, A.J. Benesi, and V.N. Reinhold, J. Bacteriol. 172:136-142, 1990). We now report the initial characterization of a novel membrane-bound glucosyltransferase activity from Bradyrhizobium japonicum USDA 110. Analysis of the product of this glucosyltransferase activity revealed the following: the presence of beta-1,3 and beta-1,6 glycosidic linkages, an average molecular weight of 2,100, and no detectable reducing terminal residues. The glucosyltransferase activity was found to have an apparent Km of 50 microM for for UDP-glucose, and activity was stimulated optimally by Mn2+ ions. On the basis of the structural properties of the in vitro glucan product, it is possible that this membrane-bound glucosyltransferase activity may be responsible for the biosynthesis of cyclic beta-1,6-beta-1,3-glucans by this organism.

Cations, Divalent↗

PubMed1991

Retrospective cohort mortality study of workers at an aircraft maintenance facility. I. Epidemiological results.

A retrospective cohort study of 14,457 workers at an aircraft maintenance facility was undertaken to evaluate mortality associated with exposures in their workplace. The purpose was to determine whether working with solvents, particularly trichloroethylene, posed any excess risk of mortality. The study group consisted of all civilian employees who worked for at least one year at Hill Air Force Base, Utah, between 1 January 1952 and 31 December 1956. Work histories were obtained from records at the National Personnel Records Centre, St. Louis, Missouri, and the cohort was followed up for ascertainment of vital state until 31 December 1982. Observed deaths among white people were compared with the expected number of deaths, based on the Utah white population, and adjusted for age, sex, and calendar period. Significant deficits occurred for mortality from all causes (SMR 92, 95% confidence interval (95% CI) 90-95), all malignant neoplasms (SMR 90, 95% CI 83-97), ischaemic heart disease (SMR 93, 95% CI 88-98), non-malignant respiratory disease (SMR 87, 95% CI 76-98), and accidents (SMR 61, 95% CI 52-70). Mortality was raised for multiple myeloma (MM) in white women (SMR 236, 95% CI 87-514), non-Hodgkin's lymphoma (NHL) in white women (SMR 212, 95% CI 102-390), and cancer of the biliary passages and liver in white men dying after 1980 (SMR 358, 95% CI 116-836). Detailed analysis of the 6929 employees occupationally exposed to trichloroethylene, the most widely used solvent at the base during the 1950s and 1960s, did not show any significant or persuasive association between several measures of exposure to trichloroethylene and any excess of cancer. Women employed in departments in which fabric cleaning and parachute repair operations were performed had more deaths than expected from MM and NHL. The inconsistent mortality patterns by sex, multiple and overlapping exposures, and small numbers made it difficult to ascribe these excesses to any particular substance. Hypothesis generating results are presented by a variety of exposures for causes of death not showing excesses in the overall cohort.

Aircraft↗

PubMed1991

Nurses' attitudes, nurse-patient interactions and adherence to treatment by hemodialysis patients.

Relationships among fluid intake and dietary-adherence of 29 hemodialysis patients, nurses' attitudes (liking-disliking) toward these patients, and selected nurses' and patients' verbalizations during hemodialysis treatment were explored. No significant associations were found. Nurses may be facilitating positive solutions to all patients' health care problems rather than admonishing those whom they dislike and/or who do not adhere to treatment.

Adult↗

PubMed1991

Longitudinal pigmented nail bands.

In this article, we have discussed the possible causes of a longitudinal pigmented nail band. A thorough history, physical examination, and, when indicated, biopsy of the origin of the band should reassure the patient with a benign lesion and direct further treatment of a patient with a malignant or potentially malignant lesion.

Humans↗

PubMed1991

Intrarectal sonography. A new technique for the assessment of rectal tumors.

Preoperative staging of rectal tumors provides a selective therapeutic approach. Twenty-three patients were evaluated with prospective intrarectal sonography. Endosonography identified all 21 rectal lesions. Two patients with previous rectal carcinoma had no evidence of recurrence. Thirteen of 17 patients (76%) with rectal carcinoma were correctly staged by endosonography. A submucosal leiomyosarcoma and pararectal arachnoid cyst were correctly identified. Preoperative assessment of lymph node status was accurate in five of ten patients (50%). Results of preoperative digital rectal examination predicting rectal wall involvement correlated with pathologic findings in 11 of 15 patients (73%). Intrarectal sonography is an important staging technique for preoperative evaluation of rectal wall invasion and guides appropriate surgical intervention.

Adult↗

PubMed1990

Isolation of large numbers of enriched human megakaryocytes from liquid cultures of normal peripheral blood progenitor cells.

Investigations linking human megakaryocyte development and cell biology have been hindered by an inability to obtain large, relatively pure megakaryocyte cell preparations from in vitro stem cell cultures. We report here that such preparations can be generated from liquid cultures of normal human peripheral blood mononuclear cells stimulated by a serum source of megakaryocyte colony stimulating activity (Meg-CSA, the 0% to 60% ammonium sulfate protein fraction of aplastic canine serum). Adherent-depleted peripheral blood mononuclear cells are suspended at 5 x 10(5) to 10(6) cells/mL in supplemented liquid culture medium, platelet-poor human plasma 20% (vol/vol) and 1 to 2 mg/mL serum Meg-CSA protein. After 12 to 14 days of incubation, megakaryocytes constitute 3.0 +/- 2.9% (mean +/- SD, n = 8) of the unseparated cultured cell population. Megakaryocytes can be enriched by counterflow centrifugal elutriation to a purity of 58 +/- 14% (+/- SD) with a recovery of 13 +/- 7% and a viability of 67 +/- 19%. This algorithm results in the average isolation of approximately 3 x 10(5) enriched megakaryocytes from a 100-mL starting volume of peripheral blood. Cultured megakaryocytes exhibit normal light and ultrastructural morphology by Wright-Giemsa staining and electron microscopic analysis. After a 12-day culture interval, enriched megakaryocyte preparations exhibit morphologic stage distributions that are similar to normal human marrow. Stage distributions move rightward with culture duration indicating partial synchrony of megakaryocyte maturation. On cytospin preparations, megakaryocyte diameter averages 30.2 +/- 1.5 microns and increases with maturation stage. Flow cytometric analyses demonstrate the expression of platelet glycoproteins (GP) Ib and IIb/IIIa by the cultured megakaryocytes. The modal ploidy of the enriched cells at day 12 of culture is 16N and most remaining megakaryocytes are 8N or 32N. Liquid culture of serum Meg-CSA-stimulated human peripheral blood mononuclear cells represents a valuable investigative tool that should permit studies of human megakaryocyte biology that have not been possible in the past.

Algorithms↗

PubMed1990

Human serum megakaryocyte colony-stimulating activity appears to be distinct from interleukin-3, granulocyte-macrophage colony-stimulating factor, and lymphocyte-conditioned medium.

Sera from patients with bone marrow megakaryocyte aplasia are a rich source of megakaryocyte colony-stimulating activity (Meg-CSA). Other biologic materials exhibiting Meg-CSA include phytohemagglutinin-stimulated human lymphocyte-conditioned medium (PHA-LCM), recombinant interleukin-3 (IL-3), and recombinant granulocyte macrophage colony-stimulating factor (GM-CSF). Neutralizing antisera to both recombinant IL-3 and GM-CSF were used to evaluate the relationship among these sources of Meg-CSA. Varying dilutions of IL-3 and GM-CSF antisera were tested in plasma clot cultures of normal human peripheral blood megakaryocyte progenitors optimally stimulated by either IL-3 (1 U/mL), GM-CSF (1 U/mL), PHA-LCM (2.5% to 5% vol/vol), or aplastic human serum (10% vol/vol). IL-3 antiserum at dilutions up to 1/2,000 totally abrogated megakaryocyte colony growth stimulated by IL-3. A 1/500 dilution of GM-CSF antiserum completely eliminated GM-CSF-induced megakaryocyte colony development. A combination of anti-IL-3 and anti-GM-CSF, each at a 1/500 dilution, inhibited all megakaryocyte colony growth stimulated by optimal concentrations of IL-3 and GM-CSF together. There was no neutralizing crossreactivity between the IL-3 and GM-CSF antisera. At maximally neutralizing concentrations, IL-3 antiserum inhibited 66% of the megakaryocyte colony growth stimulated by PHA-LCM. Residual megakaryocyte colony growth was eliminated by the addition of a 1/500 dilution of anti-GM-CSF.(ABSTRACT TRUNCATED AT 250 WORDS)

Anemia, Aplastic↗