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Biomedical subjects

J M Zimmerman

Publications and source records attributed to J M Zimmerman.

At least 19 recordsLinked to original sources
PubMed2004

Combination of laparoscopic adjustable gastric banding and gastric bypass: current situation and future prospects -- routine use not advised.

Although bariatric surgery has proven to be the most effective treatment for morbid obesity, most surgical techniques do have failures. In an effort to improve the reliability, several surgeons started to use a combination of a laparoscopic gastric bypass with an adjustable gastric band. Because of concerns regarding a possible negative outcome, an expert meeting was organized to evaluate the current situation and future application. In total, 104 operations were reported,with several technical variations. The overall complication rate was acceptable, but the percentage of the band erosions was 6.7%, which is too high. The potential advantages (adjustability, maintained access to the stomach and biliary tree, and reversibility) do not compensate for this complication rate. Based on the results and the opinion of the surgeons experienced in this technique, it is concluded that the combination of gastric bypass with an adjustable gastric band to form the pouch is not recommended.

Gastric Bypass↗
PubMed2000

In vitro and in vivo ligation-mediated polymerase chain reaction analysis of a polypurine/polypyrimidine sequence upstream of the mouse metallothionein-I gene.

The mouse metallothionein-I homopurine/homopyrimidine (MT-I R/Y) sequence is a 128-base pair element located approximately 1.2 kilobase pairs upstream of the MT-I gene. Previous in vitro studies of this sequence in purified plasmids indicated the formation of a non-B DNA structure stabilized by acidic pH and negative supercoiling. We now present a detailed in vitro and in vivo analysis of the MT-I R/Y sequence using chemical probes of DNA structure and ligation-mediated polymerase chain reaction. In vivo analysis suggests neither profound base unpairing nor protein binding within the MT-I R/Y sequence before or after metal induction of MT-I. We conclude for this element that the propensity to adopt an unusual DNA structure in vitro does not imply the occurrence of such a structure in vivo. We were able to show both in purified genomic DNA and in vivo that only isolated thymines and the 3' terminal thymine in strings of consecutive thymines are modified significantly by KMnO(4), indicating an altered thymine accessibility pattern within the R/Y sequence. This KMnO(4) reactivity pattern is more consistent and predictable within the R/Y sequence when compared with flanking sequences. We propose a simple steric interference model to explain the observed pattern of KMnO(4) modification of thymines.

3T3 Cells↗
PubMed2000

Design and calibration of a semi-synthetic DNA phasing assay.

Electrophoretic assays of intrinsic DNA shape and shape changes induced by ligand binding are extremely useful because of their convenience and simplicity. The development of calibrations and empirical quantitative relationships permits highly accurate measurement of DNA shape using electrophoresis. Many conventional analyses employ the unidirectional ligation of short DNA duplexes. However, many oligonucleotides (typically more than 20) must often be synthesized for a single experiment. Additionally, the length of the DNA duplex can become limiting, preventing the analysis of certain DNA sequences. We now describe a semi-synthetic electrophoretic phasing method that offers several advantages, including a reduced number of required synthetic oligonucleotides, the ability to analyze longer DNA duplexes and a simplified approach for data analysis. We characterize semi-synthetic DNA probes in electrophoretic phasing assays by ligation of synthetic duplexes containing A(5) tracts between two longer restriction fragments. Upon electrophoresis, the gel mobility is strongly correlated with the predicted DNA curvature provided by the reference A(5) tracts. Having obtained this calibration, we show that the semi-synthetic phasing assay can be readily and economically applied to analyze DNA curvature induced by DNA charge modifications and DNA bending due to peptide binding.

DNA↗
PubMed1999

Variability of atrial sensing during exercise in a patient with a dual chamber ICD caused inappropriate ICD discharges.

We present the case of a patient with a dual chamber implantable cardioverter defibrillator (ICD) who experienced inappropriate ICD discharges during exercise. Interrogation of the ICD revealed intermittent atrial undersensing during exercise that was responsible for the erroneous classification by the ICD of sinus tachycardia as ventricular tachycardia. Monitoring of the intracardiac electrograms and Marker Channels during an exercise test confirmed a marked decrease in P wave amplitude during exercise. By increasing the atrial sensitivity setting the problem was resolved.

Adult↗
PubMed1989

A physiologically based model of creatine kinase-MB release in reperfusion of acute myocardial infarction.

To gain insight into the altered kinetics of creatine kinase-MB (CK-MB) release after reperfusion, a physiologically based model with first-order CK-MB appearance and disappearance functions was postulated. This biexponential model is based on the assumption that reperfusion reestablishes nutritive blood flow, providing direct access of interstitial CK-MB to the bloodstream. This is in contrast to persistent coronary artery occlusion, in which no direct access to nutritive flow is present. The accuracy of this model was examined in 8 dogs reperfused after 2 hours of coronary artery occlusion. The fit to observed values was excellent, with a mean r2 of 0.97 +/- 0.05. In agreement with the biexponential model, the initial increase in CK-MB activity was abrupt and rapid. The same degree of accuracy was found in 21 patients with angiographic evidence of reperfusion after thrombolytic therapy (mean r2 0.97 +/- 0.02). The appearance characteristics were similar to the animal model, with an abrupt and rapid increase in CK-MB activity. When compared with 5 patients with persistent occlusion, ka, the rate constant of the appearance function, clearly distinguished patients with reperfusion (chi-square = 20.6, p less than 0.0001), whereas considerable overlap was present in the time to peak CK-MB (time to peak less than 12 hours, chi-square = 3.6, difference not significant). Alterations of CK-MB release in reperfusion can be accurately modeled with the biexponential model. The characteristics of this model suggest that early identification of reperfusion by serial CK-MB assay is possible.

Animals↗
PubMed1987

Measurement of infarct size and percentage myocardium infarcted in a dog preparation with single photon-emission computed tomography, thallium-201, and indium 111-monoclonal antimyosin Fab.

Single photon-emission tomography (SPECT) and indium 111-labeled monoclonal antimyosin Fab fragments were used to measure myocardial infarct size in 12 dogs, six subjected to balloon catheter-induced coronary artery occlusion for 6 hr (late reperfusion) and six subjected to occlusion with reperfusion at 2 hr (early reperfusion). Tomographic imaging was performed 24 hr after the intravenous injection of labeled Fab fragments with the use of a dual-head SPECT camera with medium-energy collimators. Immediately after the first tomographic scan, thallium-201 was injected into nine of 12 dogs and imaging was repeated. Estimated infarct size in grams was calculated from transaxially reconstructed, normalized, and background-corrected indium SPECT images with the use of a threshold technique for edge detection. Estimated noninfarcted myocardium in grams was calculated from obliquely reconstructed thallium SPECT images by a similar method. The animals were killed and infarct size in grams and true infarct size as a percentage of total left ventricular myocardial volume were measured by triphenyl tetrazolium chloride staining. Estimated infarct size from indium SPECT images showed an excellent correlation with true infarct size (r = .95, SEE = 4.1 g). Estimated percentage myocardium infarcted was calculated by dividing estimated infarct size from indium images by the sum of estimated infarct size plus estimated noninfarcted myocardium obtained from thallium images. Correlation between the estimated percentage of myocardium infarcted and true percentage of myocardium infarcted was excellent (r = .93, SEE = 4.4%). We conclude that dual-isotope SPECT with indium 111-monoclonal antimyosin antibodies and thallium-201 can accurately estimate infarct size and percentage myocardium infarcted.

Animals↗
PubMed1984

Antidysrhythmic actions of meobentine sulfate.

The antiarrhythmic efficacy of meobentine sulfate, a bethanidine derivative lacking inhibitory effects on adrenergic neuronal function, was assessed in three canine models. Intravenous meobentine sulfate, administered in dosages of 5.0, 10,0, and 20.0 mg/kg, produced a dose-related increase in the ventricular fibrillation threshold (VFT) under nonischemic conditions (7.6 +/- 1.8 mA vs 37.8 +/- 8.6 mA) (20 mg/kg; p less than 0.05) and during regional myocardial ischemia (5.6 +/- 1.5 mA vs 41.8 +/- 9.1 mA) (20 mg/kg; p less than 0.05). The VFT was also increased in the presence of chronic ischemic injury (6.4 +/- 1 mA to 31 +/- 10 mA) (20 mg/kg; p 0.05). In the conscious dog, 4 days after an anterior myocardial infarction, programmed electrical stimulation (PES) produced nonsustained ventricular tachycardia (VT) in five dogs. After meobentine sulfate administration, eight of nine animals had sustained VT and one animal developed ventricular fibrillation (VF). At a dose of 20 mg/kg, there was prolongation of the cycle length of the VT (169 +/- 11 msec to 237 +/- 20 msec), prolongation of the QRS duration (58 +/- 2.6 msec to 71 +/- 3.7 msec), and prolongation of the delay in epicardial activation. There was an enhanced potential after meobentine administration for programmed stimulation to produce ventricular arrhythmias with the introduction of fewer premature impulses. In the third canine model, conscious dogs with a previous anterior myocardial infarction developed VF in response to electrically induced left circumflex coronary artery injury. Meobentine (20 mg/kg) failed to prevent VF in eight of eight dogs. These results suggest that while meobentine sulfate significantly increases the electrical VFT, it does not protect the conscious canine from the induction of ventricular tachyarrhythmias in response to PES, and it does not prevent VF in a conscious canine model of sudden coronary death.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Life-table methods for evaluating antiarrhythmic drug efficacy in patients with paroxysmal atrial tachycardia.

Spontaneous variability in the occurrence of paroxysmal arrhythmias has made it difficult to apply objective and quantitative methods to describe their clinical course. In this study of paroxysmal atrial tachycardia, the "tachycardia-free interval" was used as a quantitative measure of drug efficacy during treatment with oral verapamil. The tachycardia-free interval is the time a patient remains free from an episode of tachycardia after drug treatment is begun. We documented recurrent tachycardia by telephone transmission of the electrocardiogram. Improvement caused by increasing the drug dose (360 versus 480 mg/day) or by comparing verapamil with placebo treatment was demonstrated by upward shifts in the cumulative tachycardia-free interval curves. The tachycardia-free interval is an easily measured clinical variable that has substantial promise in the study of paroxysmal arrhythmias.

Actuarial Analysis↗
PubMed1982

Pirmenol kinetics and effective oral dose.

The oral form of pirmenol has not been administered to man. Pirmenol was given by mouth to eight patients with chronic, stable premature ventricular beats (PVBs) to determine effective dose and kinetics. The patients were evaluated with a dose-ranging protocol following by a double-blind, crossover, placebo-controlled study of doses that were effective during dose ranging. Oral doses of 150 to 250 mg induced at least 90% suppression of PVBs 18 of the 19 times they were administered during both protocols. During the double blind experiment, a single oral dose of pirmenol suppressed 95 +/- 8% PVBs/hr (mean +/- SD) for 3 consecutive hr, while placebo suppressed 4 +/- 42% PVBs/hr (P less than 0.01). a 90% or greater reduction in PVBs persisted for a median of 6 hr (range 1 to 8 hr). The range of plasma pirmenol concentrations associated with an at last 90% reduction in PVBs was 0.7 to 2.0 micrograms/ml. Median half-life (t1/2) was 9.3 hr (range 6.0 to 12.4) with 86.6 +/- 2.4% protein binding and 82.6 +/- 23.6% bioavailability. At peak drug level there was lengthening of the QTc interval (0.036 sec, P less than 0.05), but no change in heart rate, blood pressure, PR interval or QRS duration, or symptoms. In this single-dose study, pirmenol effectively reduced PVBs, has a relatively long t1/2, and was minimally toxic.

Administration, Oral↗
PubMed1982

Electrocardiogram recording by telephone in antiarrhythmic drug trials.

The purpose of this study was to evaluate ECG recording by telephone as a research tool for documenting the cardiac rhythm during symptoms of paroxysmal atrial tachycardia. Eleven patients were enrolled in the study during the first year. They transmitted 34 rhythm strips during symptoms, 17 of which showed paroxysmal atrial tachycardia; only one of the 34 was uninterpretable. Three patients thought they were having paroxysmal atrial tachycardia when their rhythm strips showed that they were having sinus tachycardia. Patient compliance and satisfaction with our follow-up system were high. Our study supports the use of ECG recording by telephone as an excellent tool to document arrhythmias in patients enrolled in clinical trials.

Anti-Arrhythmia Agents↗
PubMed1979

Experience with a hospice-care program for the terminally ill.

A hospice-care program offers an opportunity to provide effective palliative care for patients terminally ill with malignant disease and to develop improved methods for coping with the problems of the dying patient. All patients for whom antitumor therapy does not offer a reasonable possibility of cure are eligible for Church Hospital's multidisciplinary program, the focus of which is on both the patient and his family. Acceptance by medical staff, patients and families has been enthusiastic. Both conventional and unconventional methods can be helpful in making terminally ill patients more comfortable. Much has been learned about the control of pain in such patients. Intestinal obstruction can often be managed non-operatively without the use of nasogastric tube. Other common symptoms such as weakness, anorexia, depression, dyspnea, etc. can be relieved with varying degrees of success. An objective of the program is to allow the patient to be at home for most of his terminal illness and to die there if possible. By utilizing patient and family instruction, visiting nurses and home health aides, approximately two-thirds of the patients in the program at any given time are at home. Basing the program in an acute care hospital has allowed coordination with the curative treatment of malignant disease and effective use of radiation and chemotherapy for palliative purposes. The organizational structure, financing, facilities and clinical experience with 100 consecutive patients of the Church Hospital hospice-care program are described.

Adolescent↗
PubMed1978

Thyroid scintigraphy: pinhole images versus rectilinear scans.

99mTc-pertechnetate thyroid scintigraphy was performed on 67 patients with a pinhole camera and a rectilinear scanner. The dual set of images was interpreted blindly by four nuclear medicine physicians. Observer performance with each of the two imaging techniques was evaluated by the receiver operating characteristic (ROC) method and by multivariate information analysis (MIA). Performance was superior for the four observers when interpreting the pinhole images, identification accuracy ranging from 70 to 94% with the pinhole images and only 49 to 63% with the rectilinear scanner.

Humans↗