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Biomedical subjects

M Geist

Publications and source records attributed to M Geist.

At least 19 recordsLinked to original sources
PubMed2001

Where do adolescents get their condoms?

PURPOSE: To determine where adolescents obtain their condoms; the availability and accessibility of condoms; condom availability in relationship to different sexually transmitted disease (STD) rates; and the availability of safer sex information in places where condoms are sold. METHODS: We conducted a random digit-dialed telephone survey of 259 14-19-year-old adolescents in Monroe County, New York. Self-reported health services use, knowledge and use of confidential services, and where adolescents obtained or intended to obtain condoms were assessed. Research assistants visited all retail establishments in five areas of similar population size with gonorrhea rates from 887 to 12,427 per 100,000 adolescents to assess how available and accessible condoms were in each store. Perceived access and actual condom availability and accessibility were compared using Chi-square and Student's t-tests. RESULTS: Trained interviewers dialed 11,800 numbers in 1993, identifying 4449 (40%) households among 11,065 numbers reached successfully. Of these, 393 (8.8%) had eligible adolescents and 259 (66%) completed interviews. Most adolescents reported obtaining, or planning to obtain, condoms in stores rather than from free health care settings. Adolescents who have used condoms more often reported having obtained them without cost than having purchased them. Condoms were available at 101 (83%) of 122 stores identified. All drug stores and 75% of supermarkets sold condoms and displayed them openly. Most small grocery stores also sold condoms (92%), but were less likely to openly display them. No stores displayed or provided safer sex information. Areas with higher STD rates had more stores (p <.01), and more stores that sold condoms (p <.01). There was no difference in condom cost by area. CONCLUSIONS: Many adolescents obtain their condoms in retail stores. Condom accessibility varied by store type and area STD rate. Increasing condom visibility in private grocery stores may increase the accessibility of condoms to adolescents in areas with highest STD rates.

Adolescent↗
PubMed2001

Effects of rhythm regularization and rate control in improving left ventricular function in atrial fibrillation patients undergoing atrioventricular nodal ablation.

OBJECTIVES: To assess the relative contributions of rate control and rhythm regularization to left ventricular function in atrial fibrillation (AF) patients undergoing atrioventricular nodal ablation. This was performed by assessing the effect of ventricular rhythm regularization on left ventricular function during AF, and the effect of varying heart rate on left ventricular function after ablation. PATIENTS AND METHODS: Eleven patients with continuous AF and V/VI-R pacemakers undergoing therapeutic atrioventricular nodal ablation were studied. Preablation patients underwent two 30 min observation periods in a randomized, blinded fashion during which they were either in baseline AF (pacer set to default V/VI 50/min) or being paced using a rhythm stabilizing algorithm (RSA) designed to regularize rhythm without changing baseline ventricular rate. Six weeks after ablation, patients were again observed during the two following 30 min periods: pacing at a low clinically indicated rate (69+/-9 beats/min), and pacing at the rapid, mean preablation rate. During all observation periods, left ventricular function was measured continuously using a nuclear vest that provided validated measures of heart rate, ejection fraction, and normalized end-systolic volume (ESV) and end-diastolic (EDV) volume. RESULTS: Before ablation, RSA successfully regularized rhythm, decreasing the coefficient of variation of interbeat intervals 20+/-5% to 10+/-4% (P<0.001). The heart rate with RSA (105+/-19 beats/min) was not significantly different from the baseline AF rate (102+/-21 beats/min). Increased rhythm regularity achieved by RSA significantly improved left ventricular function, decreasing ESV from 62+/-12 units to 57+/-11 units (P=0.03), and increasing the ejection fraction from 31+/-11% to 36+/-11% (P=0.03). After ablation, at the clinically indicated low pacing rate of 69+/-9 beats/min, a much greater improvement in ejection fraction was observed, increasing to 44+/-13% (P=0.005 compared with preablation). However, rapid regular pacing at the mean preablation rate of 110+/-18 beats/min eradicated this improvement, decreasing the ejection fraction to 31+/-8% (P=0.003), and increasing ESV from 53+/-13 units to 62+/-8 units (P=0.006). CONCLUSIONS: Rhythm regularity achieved by a regularizing pacing algorithm can significantly, albeit modestly, improve left ventricular function in AF. However, more marked improvements in left ventricular function seen after ablation are primarily due to rate reduction alone.

Aged↗
PubMed2000

Enveloped virus is the major virus form produced during productive infection with the modified vaccinia virus Ankara strain.

Modified vaccinia virus Ankara (MVA) is a highly attenuated virus strain that may be useful as a vaccine vector. Ultrastructural examination of purified MVA showed that most of the viral particles are enveloped in contrast to the Copenhagen strain (COP). In CsCl gradients, the majority of the MVA particles displayed a light buoyant density characteristic of the enveloped form. Consistent with these results, MVA particles were poorly labeled with antibodies against the surface of intracellular mature virus but strongly labeled with antibodies against an envelope antigen. Furthermore, MVA was more resistant than the COP strain to neutralization by mouse anti-COP antibodies. These results suggest that the MVA strain may be particularly suitable for the engineering of envelope proteins and that MVA may be able to resist the humoral immunity displayed by previously vaccinated individuals.

Animals↗
PubMed2000

Targeted macrophage cytotoxicity using a nonreplicative live vector expressing a tumor-specific single-chain variable region fragment.

Antigen-specific recognition and subsequent destruction of tumor cells is the goal of vaccine-based immunotherapy of cancer. Often, however, tumor antigen-specific cytotoxic T lymphocytes (CTLs) are either not available or in a state of anergy. In addition, MHCI expression on tumor cells is often downregulated. Either or both of these situations can allow tumor growth to proceed unchecked by CTL control. We have shown previously that tumor antigen-specific monoclonal antibodies can be expressed in vaccinia virus and that activated macrophages infected with this virus acquire the ability to kill tumor cells expressing that antigen. Here we show that a membrane-anchored form of the scFv portion of the MUC1 tumor antigen-specific monoclonal antibody, SM3, can be expressed on activated macrophages with the highly attenuated poxvirus, modified vaccinia Ankara (MVA), as a gene transfer vector. Cells infected with the MVA-scFv construct were shown to express the membrane-bound scFv by Western blot and FACS analysis. That cells expressing the membrane-anchored scFv specifically bind antigen was shown by FACS and by BIAcore analysis. GM-CSF-activated macrophages were infected with the construct and shown to recognize specifically MUC1-expressing tumor cells as measured by IL-12 release. Furthermore, activated macrophages expressing the membrane-bound scFv specifically lyse target cells expressing the MUC1 antigen but not cells that do not express MUC1.

Animals↗
PubMed2000

Is electrical storm in ICD patients the sign of a dying heart? Outcome of patients with clusters of ventricular tachyarrhythmias.

BACKGROUND: Electrical storm in patients with implanted cardioverter defibrillators (ICDs) is purported to carry an ominous prognosis. METHODS AND RESULTS: We retrospectively compared 40 patients with electrical storm (defined as three or more episodes of ventricular arrhythmia requiring ICD therapy in a 24 h period) with those only having isolated appropriate ICD therapy (n=57) and with patients having no or only inappropriate ICD therapy (n=125). All patients received ICDs for documented sustained VT or VF. There was no significant difference in age, sex, ejection fraction, total follow-up time, or underlying heart disease between any of the three groups. Patients who had electrical storm received their first appropriate ICD therapy 275 +/- 369 days post-implant (35% had storm as their first event) with storm occurring an average of 599 +/- 710 days post-implant. Patients had 1.5 +/- 1.0 storms in total (median= 1), with 55 +/- 91 episodes per storm. There were no significant differences in actuarial survival at 5-year follow-up between the three groups. Eighty percent of storm patients were alive 5 years post-implant. CONCLUSION: Storm is a common occurrence in ICD patients, can occur at any time during the follow-up period, and does not independently confer increased mortality.

Defibrillators, Implantable↗
PubMed2000

Permanent explantation of implantable cardioverter defibrillators.

Although ICD therapy is seen as an irrevocable mode of therapy in most patients, a small number of patients do have their devices permanently explanted. The long-term outcome in these patients has not been described. The purpose of this single center study was to evaluate the long-term outcome of patients whose ICD was explanted and not replaced and to propose clinical variables that can be considered when making the decision to discontinue therapy. Ten of 323 (3.1%) patients in our ICD registry had their devices permanently explanted or turned off between 1986 and December 1998. The devices had been in place for 39 +/- 31 months preexplant. No patient had received appropriate therapy prior to surgery, which was indicated for infection or lead fracture. All patients are alive and well 75 +/- 30 months postexplant with 1 (10%) patient requiring late reimplantation. We reviewed the English language literature describing ICD explanation without replacement. A total of 151 patients were reported in eight studies and were followed for up to 30 months postexplant. Excluding patients with terminal illness or heart transplantation 57.6% survived without reimplantation. In selected patients, after not using an ICD for a long period and when clinical circumstances justify, device therapy may be discontinued with some degree of safety.

Adult↗
PubMed2000

Transvenous pacemaker leads do not worsen tricuspid regurgitation: a prospective echocardiographic study.

Limited prospective data are available regarding the influence of pacemaker leads on tricuspid valve function. To examine the true incidence of these complications, 35 patients were prospectively examined by two-dimensional and Doppler echocardiography before and after implantation of either a permanent pacemaker or an automatic implantable cardioverter-defibrillator. Of the 35 patients imaged preoperatively, the amount of tricuspid regurgitation (TR) was judged as normal or trivial in 15 (43%), mild in 10 (29%), moderate in 8 (23%), and severe in 2 (6%). Following electrode implantation, TR was noted to be normal or trivial in 13 (38%), mild in 15 (48%), moderate in 6 (17%) and severe in 1 (3%). We conclude that implantation of permanent right ventricular electrodes is not usually associated with an acute worsening of tricuspid regurgitation in most patients.

Aged↗
PubMed1999

Validation of a noninvasive measure of local myocardial repolarization in a conscious human model: adaptation of repolarization to changes in rate.

INTRODUCTION: A commercial pacemaker sensor measure of the unipolar endocardial stimulus to T wave interval may accurately reflect changes in the monophasic action potential duration at 90% repolarization (APD90). This sensor system was used to study the kinetics of adaptation of repolarization duration to changes in heart rate in humans. METHODS AND RESULTS: Patients were studied using an external pacemaker capable of displaying all stimulus to T wave intervals for each paced beat. Right ventricular stimulation was delivered via the pacemaker and compared simultaneously to APD90. Steady-state pacing was simulated by 60 seconds of pacing at cycle lengths (CLs) 350 to 700 msec. Adaptation to a new ventricular rate was analyzed with a sudden 200-msec decrease in CL. The relation between repolarization measure and steady-state CL (n = 16) was linear with a slope of 0.16 and 0.19 for APD90 and stimulus to T wave interval, respectively (P = NS). The adaptation of both repolarization measures to a sudden change in rate were best modeled by a biexponential function. Stimulus to T wave interval exhibited a parallel course to APD90, and an analysis of normalized differences between APD90 and stimulus to T wave interval followed an approximately normal distribution, with 93.5% of the paired differences within 2 SD of the mean. CONCLUSION: A pacemaker sensor measure of stimulus to T wave interval accurately parallels APD90 during both steady-state and sudden changes in rate. Repolarization in human endocardium follows a linear relation to steady-state CL and adapts to a new rate with a biexponential function. This model represents a novel method for studying human cardiac repolarization.

Action Potentials↗
PubMed1996

Hyperaldosteronism and sudden cardiac death.

From a database of 130 implantable cardiac defibrillator recipients, 2 patients (1.5%) with sudden cardiac death as a presenting symptom, leading to diagnosis of primary hyperaldosteronism, are described. This is a newly described cause of sudden cardiac death, possibly more frequent than suspected, which should be considered in patients with malignant arrhythmias and hypokalemia.

Adult↗
PubMed1996

Mechanisms of cardiopulmonary resuscitation in a patient with right ventricular dilatation--an echocardiographic contribution.

The mechanism of cardiopulmonary resuscitation is still debated. Two different theories have been proposed: direct cardiac compression versus intrathoracic pressure. A patient with dilated right cardiac chambers, who underwent a transesophageal echocardiography study during cardiopulmonary resuscitation, is reported. The direct compression mechanism was clearly demonstrated.

Adult↗
PubMed1995

One-stage coronary angiography and angioplasty.

The combination of diagnostic angiography and angioplasty as a single procedure is becoming common practice in many institutions, but the feasibility and safety of this strategy have not been reported. This report describes 2,069 patients who underwent coronary angioplasty over a 3-year period at an institution where combined angiography and angioplasty is the norm. All patients were prepared before angiography for potential immediate angioplasty. In 1,719 patients, angioplasty was performed immediately after the diagnostic angiogram, while separate procedures were performed in 350 patients. Of those 350 patients, 254 were referred for angioplasty after diagnostic angiography at other hospitals. One thousand one hundred ninety-seven patients were admitted electively for treatment of stable angina pectoris, and 872 underwent procedures during hospitalization for unstable angina or acute myocardial infarction. One thousand nine hundred seven patients (92.2%) had successful angioplasties; in 130 patients (6.3%) the lesion could not be dilated, but no complication occurred, and in 32 patients (1.5%) angioplasty ended with a major complication (0.8% death, 1.0% Q-wave myocardial infarction, 0.5% emergency coronary artery bypass surgery). There was no difference between the combined and staged groups with regard to success, major and minor complication rates or in length of hospitalization after angioplasty. We conclude that routine combined strategy for angiography and angioplasty is feasible, safe, easier for the patient, and more cost-effective than 2 separate procedures.

Angina Pectoris↗
PubMed1994

Recombinant MUC 1 vaccinia virus: a potential vector for immunotherapy of breast cancer.

Breast cancer is considered as the major cause of mortality by cancer for women. Even if chemotherapy, radiotherapy and surgery have improved the life expectancy of patients bearing tumours, breast cancer is responsible for the death of 42,000 women per year in USA and 25,000 women in France. In this context, cancer vaccines may add an attractive alternative therapeutic strategy to the current existing treatments. We describe here the construction of recombinant vaccinia viruses co-expressing a tumour associated antigen (MUC 1) and an "adjuvant" cytokine, which have potential applications in the active immunotherapy of breast cancer. Indeed, recombinant vaccinia viruses have been extensively used during the past decade to induce a protective response against a whole variety of pathogens, and has proven to be of great value in the elicitation of a cellular immune response leading to the rejection of tumour grafts in mouse models.

Animals↗
PubMed1993

[The safety belt: effects on injury patterns of automobile passengers].

Since 1984 the law concerning safety belts has been implemented; this paper deals with the findings in 386 victims of motor accidents who were x-rayed between 1981 and 1989. Minor injuries have been ignored. The number of passengers wearing belts increased by 30% after 1984. The number of passenger injuries did not decrease. Injuries directly caused by the belts included a small number of fractures of clavicles, the sternum and ribs and one pelvic fracture, one serious abdominal injury with tearing of the mesenteric artery and one ruptured spleen. An indirect result of wearing seat belts was a marked increase in cervical whiplash injuries and some increase in thoracic vertebral fractures. None of the belt induced injuries proved fatal. Amongst those using seat belts there was a significantly lower fatality rate and injuries causing prolonged disability. In particular, using seat belts, serious injuries to the skull and brain were reduced by 80%. Similarly injuries to the abdomen, the odontoid, pelvis and hip joint were greatly reduced. The advantages of wearing a seat belt greatly outweigh the disadvantages.

Accidents, Traffic↗
PubMed1993

Cardiac rupture during coronary angioplasty.

Cardiac rupture is a catastrophic complication of acute myocardial infarction. We describe a patient with acute myocardial infarction who received thrombolytic therapy and then developed cardiac rupture and tamponade during rescue angioplasty.

Angioplasty, Balloon, Coronary↗
PubMed1992

[Dilutional hyponatremia and convulsions after strenuous exercise].

A 15-year-old girl who drank excessive amounts of water while walking in the desert on a warm day, is reported. Due to complaints of fatigue and headache she was treated with more fluids and had a generalized seizure. On admission her sodium level was 125 meq/l and serum muscle enzymes were increased. Hyponatremia due to exertion and dilution is well established and may be more common than thought. It can present as a generalized seizure and with rhabdomyolysis. This case illustrates the danger of overzealous water replacement, especially without adequate replacement of salts. When water discipline is in force this possibility should be considered in patients presenting after prolonged, strenuous exercise or marching.

Adolescent↗