PubMed Health⌕ Search

Biomedical subjects

B Eisenberg

Publications and source records attributed to B Eisenberg.

At least 19 recordsLinked to original sources
PubMed1997

Efficacy of selective unilateral exploration in hyperparathyroidism based on localization tests.

OBJECTIVES: To determine the success of unilateral exploration vs bilateral exploration for primary hyperparathyroidism and to analyze the validity of preoperative localization tests. DESIGN: Case-control study of patients who underwent surgical exploration (unilateral, n = 43; bilateral, n = 57) by 1 surgeon from January 1991 through May 1996 and who had ultrasound examination of the neck and thallium-technetium scintigraphy performed before parathyroid surgery. Initially, unilateral exploration was used sparingly, but it became the standard approach in 1994 if localization was correct. SETTING: Urban multispecialty clinic, teaching hospital. PATIENTS: One hundred consecutive patients who underwent surgical exploration for primary hyperparathyroidism. INTERVENTIONS: Ultrasonography of the neck, thallium-technetium scintigraphy, and parathyroidectomy. MAIN OUTCOME MEASURES: Imaging success, operative success, and operative time. RESULTS: In 94 patients with solitary adenomas, the adenoma was demonstrated by ultrasound scans in 66%, by thallium-technetium scintigraphy in 83%, and by either test in 87%. Correct identification by ultrasonography was 59%; by thallium-technetium scintigraphy, 75%; and together, 73%. Of 6 patients with multiple-gland disease, 2 were correctly identified by localization tests and 9 of 15 abnormal glands were demonstrated. Of the 43 unilateral explorations, 43 single adenomas and no cases of multiple-gland disease were identified; of the 57 bilateral explorations, 51 single adenomas and 6 cases of multiple-gland disease were identified. No complications occurred in either group. Hypercalcemia persisted in 3 patients who underwent bilateral exploration and recurrent hypercalcemia developed in 1 patient in each group. The average operative time for the unilateral procedure was 105 minutes, and for the bilateral procedure, 184 minutes (P < .001). Since 1994, 31 (66%) of 47 patients have had unilateral exploration based on correct localization tests. CONCLUSIONS: Unilateral exploration that is based on the results of localization tests requires less operative time and produces results similar to bilateral exploration.

Adenoma↗
PubMed1997

Permeation through the calcium release channel of cardiac muscle.

Current voltage (I-V) relations were measured from the calcium release channel (CRC) of the sarcoplasmic reticulum of cardiac muscle in 12 KCl solutions, symmetrical and asymmetrical, from 25 mM to 2 M. I-V curves are nearly linear, in the voltage range +/- 150 mV approximately 12kT/e, even in asymmetrical solutions, e.g., 2 M // 100 mM. It is awkward to describe straight lines as sums of exponentials in a wide range of solutions and potentials, and so traditional barrier models have difficulty fitting this data. Diffusion theories with constant fields predict curvilinear I-V relations, and so they are also unsatisfactory. The Poisson and Nernst-Planck equations (PNP) form a diffusion theory with variable fields. They fit the data by using adjustable parameters for the diffusion constant of each ion and for the effective density of fixed (i.e., permanent) charge P(x) along the channel's "filter" (7-A diameter, 10 A long). If P(x) is described by just one parameter, independent of x (i.e., P(x) = P0 = -4.2 M), the fits are satisfactory (RMS error/RMS current = 6.4/67), and the estimates of diffusion coefficients are reasonable D(K) = 1.3 x 10(-6) cm2/s, D(Cl) = 3.9 x 10(-6) cm2/s. The CRC seems to have a small selectivity filter with a very high density of permanent charge. This may be a design principle of channels specialized for large flux. The Appendix derives barrier models, and their prefactor, from diffusion theories (with variable fields) and argues that barrier models are poor descriptions of CRCs in particular and open channels in general.

Calcium↗
PubMed1997

Permeation through an open channel: Poisson-Nernst-Planck theory of a synthetic ionic channel.

The synthetic channel [acetyl-(LeuSerSerLeuLeuSerLeu)3-CONH2]6 (pore diameter approximately 8 A, length approximately 30 A) is a bundle of six alpha-helices with blocked termini. This simple channel has complex properties, which are difficult to explain, even qualitatively, by traditional theories: its single-channel currents rectify in symmetrical solutions and its selectivity (defined by reversal potential) is a sensitive function of bathing solution. These complex properties can be fit quantitatively if the channel has fixed charge at its ends, forming a kind of macrodipole, bracketing a central charged region, and the shielding of the fixed charges is described by the Poisson-Nernst-Planck (PNP) equations. PNP fits current voltage relations measured in 15 solutions with an r.m.s. error of 3.6% using four adjustable parameters: the diffusion coefficients in the channel's pore DK = 2.1 x 10(-6) and DCl = 2.6 x 10(-7) cm2/s; and the fixed charge at the ends of the channel of +/- 0.12e (with unequal densities 0.71 M = 0.021e/A on the N-side and -1.9 M = -0.058e/A on the C-side). The fixed charge in the central region is 0.31e (with density P2 = 0.47 M = 0.014e/A). In contrast to traditional theories, PNP computes the electric field in the open channel from all of the charges in the system, by a rapid and accurate numerical procedure. In essence, PNP is a theory of the shielding of fixed (i.e., permanent) charge of the channel by mobile charge and by the ionic atmosphere in and near the channel's pore. The theory fits a wide range of data because the ionic contents and potential profile in the channel change significantly with experimental conditions, as they must, if the channel simultaneously satisfies the Poisson and Nernst-Planck equations and boundary conditions. Qualitatively speaking, the theory shows that small changes in the ionic atmosphere of the channel (i.e., shielding) make big changes in the potential profile and even bigger changes in flux, because potential is a sensitive function of charge and shielding, and flux is an exponential function of potential.

Computer Simulation↗
PubMed1997

Parathyroid scintigraphy.

Scintigraphy of the parathyroid glands continues to be controversial from several standpoints, including radiopharmaceutical choice, imaging protocol, results, and utility in clinical situations. This article reviews: the anatomy, physiology and pathology of the parathyroid glands; mechanisms of radiopharmaceutical localization; commonly accepted imaging protocols; image results; and the appropriate use of parathyroid scintigraphy.

Humans↗
PubMed1996

Role of LFA-3, ICAM-1, and MHC class I on the sensitivity of human tumor cells to LAK cells.

Cellular adhesion molecules have been shown to be involved in tumor cell killing by cytotoxic cells such as natural killer (NK), lymphokine-activated killer (LAK), and T cells, but the precise mechanisms involved have not been clearly determined and a single target molecule has not been identified. We have examined the relative sensitivities of a panel of human tumor cell lines to LAK cell-mediated killing, in order to correlate their sensitivities with LAK cell-tumor cell binding determined by flow cytometry, and also with expression of molecules putatively involved in both the adhesion and recognition process. Two cell adhesion molecules in the immunoglobulin supergene family lymphocyte function-associated antigen (LFA-3) and intercellular adhesion molecule (ICAM-1) expression by tumor cells were examined in detail with respect to the degree of LAK cell-tumor cell conjugation and cytotoxicity. LAK sensitivity of the tumor cell lines was not clearly related to the degree of binding and correlated most strongly with the level of LFA-3 expressed on these cell lines. Major histocompatability complex (MHC) Class I antigen (Ag) expression by tumors was also examined and correlated with an inhibitory effect on LAK cell-mediated killing. Interferon-gamma(IFN) treatment of two of these tumor lines decreased their sensitivity to LAK, and treated cells exhibited a higher level of MHC Class I Ag and ICAM-1 and an increased degree of conjugation with LAK cells. These findings demonstrate roles for LFA-3, ICAM-1, and MHC Class I expression in the LAK cell-tumor cell recognition and triggering of the lytic process.

Antigens, Surface↗
PubMed1995

Gastroparesis in diabetics on chronic dialysis: clinical and laboratory associations and predictive features.

Clinical and laboratory features and risk factors for diabetic gastroparesis (DGP) were investigated in 226 diabetics on chronic dialysis; 106 subjects (43%) had DGP diagnosed by persistent vomiting improved with the use of prokinetic agents and 120 (control group) had no clinical DGP. Type 1 diabetics had DGP more frequently than type 2 diabetics (70 vs. 37%). The DGP group had longer duration of diabetes (21 +/- 8 vs. 13 +/- 6 years), higher frequency of diabetic orthostatic hypotension (95 vs. 33%), enteropathy (49 vs. 5%), blindness (52 vs. 23%), myocardial infarction (86 vs. 42%), extremity gangrene (54 vs. 27%) and cerebrovascular accidents (43 vs. 25%), lower serum albumin 32.3 +/- 3.9 vs. 35.4 +/- 3.8 g/l), urea (24.0 +/- 5.5 vs. 25.5 +/- 5.5 mmol/l) and creatinine (710 +/- 210 vs. 820 +/- 220 mumol/l), and higher serum TCO2 (20.9 +/- 3.1 vs. 19.8 +/- 2.7 mmol/l) than the control group (all differences significant at p +/- 0.004). Glycemic control was adequate in 24% of the DGP group subjects and 83% of the control subjects (p < 0.001). Annual hospitalization rate was 49 +/- 48 days/patient in the DGP group and 16 +/- 27 days/patient in the control group (p < 0.001). Median patient survival was 24 +/- 2 months in the DGP group and 61 +/- 9 months in the control group (p < 0.0001). Logistic regression identified long duration of diabetes and poor glycemic control as risk factors for DGP. In diabetics on dialysis, DGP is associated with high frequency of other diabetic complications, low serum albumin and creatinine, and high morbidity and mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Is CT portography (CTAP) really useful in patients with liver tumors who undergo intraoperative ultrasonography (IOUS)?

The objectives were to compare the role of CT during arterial portography (CTAP) and intraoperative ultrasound (IOUS) in the management of patients with primary or metastatic liver tumors; to study the ability of CTAP to define resectability before laparotomy in these patients; and to study whether the omission of CTAP in the imaging algorithm resulted in a diminished resectability rate. Eighty-eight consecutive patients with primary or metastatic liver cancer who underwent CTAP and/or IOUS between January 1990 and December 1993 were reviewed. Thirty patients had both CTAP and IOUS and underwent 31 laparotomies (Group I). The sensitivity of these two tests to detect liver tumors was compared. Twenty-eight explorations were performed for hepatic metastases and three for hepatocellular carcinoma. Fifty-three patients, including those in group I, underwent CTAP before laparotomy and were studied to assess the sensitivity of CTAP in determining unresectability (Group II). Thirty-five patients (Group III) had IOUS only and were studied to determine whether the omission of CTAP decreased the resectability rate. In Group I, 52 hepatic lesions were found by a combination of imaging studies, operative exploration, and pathologic examination. The sensitivity of CT, CTAP, IOUS, and exploration were 67 per cent, 65 per cent, 100 per cent, and 75 per cent, respectively. IOUS was more sensitive than any other modality in detecting liver tumors (P < 0.001). It added new information in 7/31 cases (23%). The false positive rate of CTAP was 4/31 (13%). In one case (3%), a false positive result would have precluded a curative resection. CTAP changed management of 4/53 patients (7.5%) by showing unresectable disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1994

Preoperative chemoradiation for adenocarcinoma of the pancreas and duodenum.

PURPOSE: This study was designed to evaluate the effects of preoperative chemoradiation on resectability, response, local control, and survival in patients with local or local-regional involvement from carcinoma of the pancreas or cancer of the duodenum and to assess the associated toxicity of such treatment. METHODS AND MATERIALS: This prospective pilot study of preoperative chemoradiation was initiated in 1986 for patients with clinical evidence of adenocarcinoma of the pancreas or duodenum without evidence of distant metastases. Radiation was given at 1.8 Gy per day to a total dose of 50.4 Gy. Two cycles of chemotherapy were given concurrent with radiation. On days 2-5 and 29-32, 5-fluorouracil (1 gm/m2/24 h x 4 days) was given, while mitomycin-C (10 mg/m2) was given on day 2 only. Surgical resection was 4-6 weeks following completion of chemoradiation. Thirty-one patients (17 male and 14 female) were entered on the protocol with a median potential follow-up of 4.5 years (range 6 months to 7.5 years). The median age was 64 years (range 32-73 years). Twenty-seven patients had pancreatic cancer (25 head, two body), while four patients had carcinoma arising from the duodenum. Twenty-one patients were initially judged to be unresectable and ten potentially resectable prior to chemoradiation. RESULTS: Twenty-nine of 31 patients completed the entire course of radiation and both cycles of chemotherapy. Acute toxicity from chemoradiation consisted of nausea, vomiting, diarrhea, stomatitis, or hematologic suppression which was moderate to severe (Grade 3 or 4) in seven patients (23%). One patient died of sepsis following the first week of therapy. Seventeen patients (55%) underwent curative resection with subtotal or total pancreatectomy or Whipple resection (four duodenum, 13 pancreas) and two (2/17) had pathologic nodal involvement, while (0/17) none had involved margins. A complete pathologic response was seen in all four (4/4) patients with duodenal cancer and in none (0/13) with pancreatic cancer who underwent resection. The median postoperative hospitalization stay was 22 days (range 4-144 days). Of 17 patients who underwent curative resection, there were two postoperative mortalities (12%). Late complications have included abscess, one; and nonmalignant ascites, five. Ten of the 31 patients are alive. For patients with pancreatic cancer the median survival is 9 months, while survival at 1 year and 3 years are 36% and 19% overall and 60% and 43% at 1 and 3 years for those undergoing resection. Six of the 27 patients (22%) with pancreatic cancer are alive without recurrence. All four patients with duodenal cancer are alive without recurrence (12 months, 23 months, 35 months, 90 months). CONCLUSION: Preoperative chemoradiation for cancer of the pancreas and duodenal region was relatively well-tolerated and enhanced resectability and downstaging of nodal metastases were suggested. The 3-year survival, particularly in patients who underwent resection, was high. For these reasons the applicability of this treatment regimen for pancreatic cancer is presently being studied in a group-wide multi-institutional Phase II trial. Chemoradiation for duodenal cancer has produced a complete pathologic response in all patients and survival has been excellent, suggesting efficacy of this regimen for duodenal cancer.

Adenocarcinoma↗
PubMed1994

Tc-99m sulfur colloid demonstration of diffuse pulmonary interstitial extramedullary hematopoiesis in a patient with myelofibrosis. A case report and review of the literature.

A 60-year-old man with a myeloproliferative syndrome and extramedullary hematopoiesis had progressive respiratory and cardiac insufficiency during the previous 18 months, with advancing interstitial pulmonary disease on chest x-ray. During analysis of his respiratory disease, results of a transbronchial biopsy showed interstitial involvement with increased numbers of megakaryocytes and other panhematopoietic staining elements. Results of a bone marrow scan demonstrated diffuse replacement of pulmonary interstitium with bone marrow, as a component of known ongoing extramedullary hematopoiesis.

Bone Marrow↗
PubMed1993

The role of mastectomy in patients with stage I-II breast cancer presenting with gross multifocal or multicentric disease or diffuse microcalcifications.

PURPOSE: Women with Stage I-II invasive breast cancer who present with gross multicentric disease or diffuse microcalcifications have a significant risk of breast recurrence when treated with conservative surgery and radiation. The purpose of this report is to present the results of mastectomy in this group of patients. METHODS AND MATERIALS: Between 1982 and 1989, 88 patients with clinical Stage I-II breast cancer who presented with clinical and mammographic evidence of gross multicentric disease or diffuse microcalcifications underwent modified radical mastectomy. Median followup was 4 years for the 57 patients with gross multicentric disease and 5.6 years for 31 patients with diffuse microcalcifications. At the time of mastectomy, 42% of patients were found to have positive axillary nodes. Following mastectomy, 15 patients received post mastectomy radiation and 35 patients received adjuvant systemic chemotherapy. RESULTS: When compared to a group of 1295 patients with unifocal, Stage I-II breast cancer, treated with conservative surgery and radiation during the same time period, patients with gross multicentric disease and diffuse microcalcifications had a significantly higher incidence of > or = 4 positive nodes, patients with gross multicentric disease had a lower incidence of positive resection margins following mastectomy and patients with diffuse microcalcifications were younger. The 5-year actuarial risk of an isolated local-regional recurrence was 8% for patients with gross multicentric disease or diffuse microcalcifications and 7% for patients with unifocal disease. Patients with gross multicentric disease or diffuse microcalcifications and > or = 4 positive axillary nodes who did not receive post mastectomy radiation had an increased risk for local regional recurrence. There were no significant differences in the 5-year actuarial overall or relapse-free survival (88% and 73% gross multicentric disease, 97% and 86% diffuse microcalcifications and 90% and 79% unifocal disease), freedom from distant metastasis (76% gross multicentric disease, 90% diffuse microcalcifications, 86% unifocal disease) or incidence of contralateral breast cancer (10% gross multicentric disease, 13% diffuse microcalcifications, 8% unifocal disease) among the three groups. CONCLUSION: The present study demonstrates no increased risk of local-regional recurrence in patients with gross multicentric disease or diffuse microcalcifications undergoing mastectomy in contrast to the increased risk of breast recurrence in patients with gross multicentric disease undergoing conservative surgery and radiation. Indications for post mastectomy radiation include > or = 4 positive nodes or close or positive surgical margins. Despite a significantly higher incidence of > or = 4 positive nodes, patients with gross multicentric disease and diffuse microcalcifications have a 5-year actuarial overall and relapse-free survival comparable to a group of patients with unifocal disease treated with conservative surgery and radiation.

Actuarial Analysis↗
PubMed1993

Volumetric analysis of small bowel displacement from radiation portals with the use of a pelvic tissue expander.

PURPOSE: Many techniques and devices have been used in an attempt to minimize gastrointestinal morbidity of pelvic irradiation. The value of a temporary intrapelvic tissue expander to displace small bowel from pelvic radiotherapy fields was analyzed by comparing volumetric treatment parameters of patients with and without such a device. METHODS AND MATERIALS: Between 1983 and 1991, 77 patients with a diagnosis of endometrial (n = 35), colorectal (n = 41), or anal carcinoma (n = 1) received adjuvant postoperative radiotherapy after undergoing treatment planning simulation with the use of small bowel oral contrast medium. Fourteen of these patients underwent surgical placement of a temporary intrapelvic tissue expander prior to radiotherapy, and 63 patients did not. Small bowel volume within the treatment portals was measured for both initial pelvic and conedown fields for all cases, and compared between the two patient groups. RESULTS: The volume of small bowel within the initial pelvic fields receiving full dose irradiation was significantly less among patients with a tissue expander. For patients with a tissue expander, mean volume receiving full dose irradiation was 25 cm3 (median 0 cm3, range 0-297 cm3), whereas the corresponding volume was 239 cm3 (median 181 cm3, range 0-943 cm3) without a tissue expander (p < .0001). A similar reduction of irradiated small bowel volume was noted in the conedown fields with the use of a tissue expander (p = .07). Volumes receiving less than full dose irradiation were also less within the initial pelvic (p = .0001) and conedown (p = .002) fields with a tissue expander. Multivariate analysis of patient and treatment-related parameters showed the use of a tissue expander to be the only factor correlated with decreased small bowel volume within the treatment field (p = .003). Morbidity related to placement and removal of the tissue expander was acceptable. Acute radiation-related morbidity was significantly less in patients irradiated with a tissue expander in place (p < .001). CONCLUSIONS: Placement of an intrapelvic tissue expander was correlated with decreased small bowel volume within the radiotherapy treatment field. Diminished radiation-induced acute gastrointestinal morbidity was noted with use of a tissue expander.

Aged↗
PubMed1993

Hand dysfunction in patients on chronic hemodialysis.

We studied hand function by clinical examination (sensory, motor, coordination, activities of daily living), hand roentgenograms, and nerve conduction studies in 26 patients, aged 62 +/- 11 (SD) years and dialyzed by hemodialysis for 7 +/- 6 years. Multiple sensory deficits were found in 98% of the hands. Motor function and coordination were abnormal in two-thirds of the hands. Roentgenograms were abnormal in 88% of the hands. Metabolic bone disease, joint disease and extraosseous calcifications were detected often. Nerve conduction studies disclosed polyneuropathy and carpal tunnel syndrome, alone or combined, in 90% of the hands. Clinical examination was sensitive, but not specific in detecting neuropathy, and could not distinguish accurately between polyneuropathy and carpal tunnel syndrome. Organic causes of progressive severe hand dysfunction included carpal tunnel syndrome and, in diabetics only, hand gangrene. Disuse led also to hand dysfunction, even in the absence of anatomic hand disease.

Activities of Daily Living↗
PubMed1993

Effect of "standing" on spasticity, contracture, and osteoporosis in paralyzed males.

The effect of "standing" in a frame on spasticity (clinical assessment and H-reflex), contracture (lower extremity joint range of motion), and osteoporosis (dual photon absorptiometry) was studied in six paralyzed males (mean age 49 yr) who had been confined to wheelchairs for an average of 19 years. Standing time averaged 144 hours over a mean of 135 days. Clinical Assessment measured reflexes, tone, and clonus in the legs. Results revealed no important differences between initial and final scores for clinical assessment and joint range of motion. In three subjects for whom H-reflexes were found, latency and amplitude were not altered by "standing." Bone density was normal in the lumbar spine but significantly reduced in the femoral neck. "Standing" did not modify the bone density in any site. A follow-up interview revealed that 67% of subjects continued to "stand" and felt healthier because of it. In summary, "standing" had no ill effects, did not alter measured variables, and had a positive psychological impact.

Absorptiometry, Photon↗
PubMed1992

The two-view radionuclide ventriculogram. Advantages of the LPO view.

This report is a prospective study of 33 male patients who underwent both contrast ventriculography (CVG) and radionuclide ventriculography (RVG) within a 24-hour period. Expert, blinded observers graded the left ventricle's regional wall motion (RWM) in the left anterior descending (LAD), left circumflex (LCx), and posterior descending arterial (PDA) distributions on right anterior oblique (RAO), and left anterior oblique (LAO) CVGs, and on anterior (ANT), LAO, 70 degrees left anterior oblique (LAO70), and left posterior oblique (LPO) RVGs. When statistically compared with CVG RWM standard data, RVG studies composed of LAO and LPO views were equal to the RVG studies composed of ANT, LAO, and LAO70 views in assessment of the LAD and LCx distributions. The RVG with LAO and LPO views was superior to the RVG with ANT, LAO, LAO70 in the detection of the posterior descending artery RWM. The authors conclude that accurate assessment of RWM is efficiently performed with the RVG composed of LAO and LPO views.

Coronary Artery Disease↗