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Biomedical subjects

M Alter

Publications and source records attributed to M Alter.

At least 19 recordsLinked to original sources
PubMed2003

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections in health care workers (HCWs): guidelines for prevention of transmission of HBV and HCV from HCW to patients.

The transmission of viral hepatitis from health care workers (HCW) to patients is of worldwide concern. Since the introduction of serologic testing in the 1970s there have been over 45 reports of hepatitis B virus (HBV) transmission from HCW to patients, which have resulted in more than 400 infected patients. In addition there are six published reports of transmissions of hepatitis C virus (HCV) from HCW to patients resulting in the infection of 14 patients. Additional HCV cases are known of in the US and UK, but unpublished. At present the guidelines for preventing HCW to patient transmission of viral hepatitis vary greatly between countries. It was our aim to reach a Europe-wide consensus on this issue. In order to do this, experts in blood-borne infection, from 16 countries, were questioned on their national protocols. The replies given by participating countries formed the basis of a discussion document. This paper was then discussed at a meeting with each of the participating countries in order to reach a Europe-wide consensus on the identification of infected HCWs, protection of susceptible HCWs, management and treatment options for the infected HCW. The results of that process are discussed and recommendations formed. The guidelines produced aim to reduce the risk of transmission from infected HCWs to patients. The document is designed to complement existing guidelines or form the basis for the development of new guidelines. This guidance is applicable to all HCWs who perform EPP, whether newly appointed or already in post.

DNA, Viral↗
PubMed2001

Schwannoma: challenging diagnosis.

OBJECTIVE: To discuss the presentation of a schwannoma in a 30-year-old man and to discuss the clincial features of this tumor. CLINICAL FEATURES: The patient had lower right back and abdominal pain that was made worse by any jarring motion. Magnetic resonance imaging showed an intradural extramedullary mass of the thoracic spine behind the T10 vertebral body, which was found to be a schwannoma. INTERVENTION AND OUTCOME: A full laminectomy of T10 and partial laminectomies of T9 and T11 allowed removal of the tumor. CONCLUSION: When undiagnosed abdominal pain is present, spinal tumor should be considered one possible diagnosis.

Abdominal Pain↗
PubMed2000

Anticoagulation for venous thromboembolism. What are the current options?

Venous thromboembolism remains an important cause of considerable morbidity and mortality. Low-molecular-weight heparin appears to be a safe and effective alternative to unfractionated heparin for inpatient treatment. In addition, we recommend considering its use in outpatient treatment in selected patients. When warfarin therapy is initiated, the starting dose should approximate the suspected maintenance dose. The optimal length of anticoagulation after an initial episode of venous thromboembolism is 6 months unless a persistent risk factor is identified. Thrombolytic therapy for hemodynamically stable patients remains controversial, primarily because of the potential for devastating complications.

Ambulatory Care↗
PubMed1999

Determination of antibody responses of elderly adults to all 23 capsular polysaccharides after pneumococcal vaccination.

The 23-valent pneumococcal polysaccharide vaccine was formulated to prevent invasive infection in the elderly and other high-risk populations from the most prevalent Streptococcus pneumoniae serotypes. However, the immunogenicity of all 23 vaccine polysaccharides has not been fully characterized in elderly adults. We previously reported that whereas the majority of elderly subjects had vigorous immune responses to selected pneumococcal vaccine polysaccharides, a subset of elderly individuals responded to fewer than two of seven vaccine serotypes after immunization. To determine whether these elderly low responders have a general inability to respond to pneumococcal vaccine and to determine whether elderly low responders might be identified by their responses to a few polysaccharides, we measured antibody responses of elderly adults to all 23 vaccine polysaccharides after pneumococcal immunization. As a group, elderly subjects showed a significant rise after immunization in geometric mean antibody levels to all 23 vaccine serotypes. However, when individual rather than group immune responses were assessed, the 23-valent vaccine did not appear to be uniformly immunogenic in these elderly subjects. Eleven elderly subjects (20%) had twofold increases in specific antibody after vaccination to only 5 or fewer of the 23 vaccine polysaccharides, and they did not respond to the most prevalent serotypes causing invasive disease. Antibody responses to serotype 9N were found to reliably distinguish low vaccine responders from other elderly subjects. However, no particular group of vaccine polysaccharides could be used as a marker for adequate immune responses if only postvaccination sera were analyzed.

Aged↗
PubMed1999

Stroke survival after discharge from an acute-care hospital.

BACKGROUND AND PURPOSE: Survival after a stroke is likely to be best for patients well enough to be sent home but the relative risk of dying if patients do not qualify for a home discharge has not been well studied. We investigated the survival prognosis after an initial stroke depending on the facility to which the patient was discharged after an acute initial stroke. METHODS: All patients were enrolled between July 1, 1987, and August 1, 1989, and were followed up to 4 years (mean of 24 months) until death, second stroke, or the end of the study. RESULTS: Among 662 patients who were discharged alive after hospitalization with an initial stroke, 128 (19%) went to a nursing home, 17(3%) to a short-term hospital, 140 (21%) to a rehabilitation facility, and 375 (57%) went home (discharge destination unknown for 2 patients). Compared to patients sent home after taking age, sex, selected baseline comorbidities, length of hospital stay, and neurological deficits into consideration, results from Cox proportional hazards model indicated that patients sent to a nursing home had 2.6 times greater risk of dying (95% CI = 1.81-4. 15) while those who were discharged to a rehabilitation facility had a death hazards ratio of 1.1. CONCLUSIONS: Mortality was greatest in the early months after discharge and decreased thereafter. Since the analysis was adjusted for age, sex, comorbidity, length of hospital stay, and number of neurological deficits, quality of care in a nursing home setting may account for the mortality difference but other factors such as social support network and living will instructions also need to be investigated.

Aged↗
PubMed1998

GM1 ganglioside for acute ischemic stroke. Trial design issues.

GM1 ganglioside decreases the severity of ischemic brain lesions in experimental models, although the mechanism is uncertain. In clinical trials involving patients with stroke, efficacy has been reported in some but not in others. However, some of the latter also showed efficacy after analyses not planned before the trial began. Analyses of the trials done to date revealed design differences sufficiently large so as to preclude meta-analysis of the results. Moreover, flaws in these studies may account for some of their failure to demonstrate that GM1 therapy is efficacious in ischemic stroke. Several of these flaws are discussed, including small sample size; attrition of the study cohort; inclusion of stroke severity and type that made demonstrations of a beneficial effect difficult; use of inappropriate clinical and outcome measuring instruments; delay in enrollment; inappropriate statistical analyses; inadequate dose; inappropriate route of administration; a too short duration of treatment. Improvements in these design features in future clinical trials of GM1 may yet demonstrate efficacy of this drug in acute ischemic stroke.

Activities of Daily Living↗
PubMed1998

Disposition after acute stroke: who is not sent home from hospital?

BACKGROUND: Known demographic and clinical characteristics of stroke survivors that affect selection of the facility to which they are discharged after hospitalization for an acute stroke are, for the most part, not population based and therefore may be unrepresentative. We present an analysis of such characteristics using the Lehigh Valley stroke cohort which is population based. METHOD: We enrolled patients within 1 month of onset of their initial acute stroke who were hospitalized between 1987 and 1989 at one of the eight hospitals in the Lehigh Valley, and 662 patients were discharged alive. The facility to which they were discharged was known for 660. Data on age, sex, presence of five selected comorbidities (hypertension, myocardial infarction, cardiac arrhythmia, diabetes mellitus and transient ischemic attacks), length of hospitalization and neurologic deficits from the stroke were systematically collected on standardized forms. Polytomous logistic regression was used to determine the factors associated with not being discharged home. Relative risk (RR) associated with discharge to a nursing or rehabilitation facility for each independent predictor was calculated using as the referent, those who went home. RESULTS: Older age was a statistically significant predictor of not being sent home (RR = 1.2 for nursing home placement), but gender and living with a spouse were not. Having a selected comorbidity did not increase the RR of not being sent home regardless of the type, nor did risk of not being sent home increase with more than one illness. Considering neurologic deficits from the stroke, patients with lower extremity weakness had a 2.6- and 3.5-fold risk of being sent to a nursing or a rehabilitation facility, respectively, compared to those without such weakness while for those with upper extremity weakness, the RR was 1.5 and 4.9, respectively. Language deficit imposed a RR of 3.1 and 2.3 of going to a nursing or rehabilitation facility, respectively. Right facial weakness also emerged as a significant risk factor for not being discharged home, perhaps because of its association with language deficit. The longer a patient was hospitalized after a stroke, the less likely it was that such a patient would go home (RR = 1.1/hospitalization day). CONCLUSION: Using population-based data on stroke survivors, our study showed the characteristics of patients who are less likely to be discharged home and, instead, are discharged to a nursing or a rehabilitation facility. Data like ours which were population based may be useful in discharge planning for stroke patients by policy makers and health care providers.

Acute Disease↗
PubMed1997

Stroke recurrence in diabetics. Does control of blood glucose reduce risk?

BACKGROUND AND PURPOSE: Patients with diabetes are at increased risk of stroke. Risk might be reduced if blood glucose level were controlled. METHODS: In a population-based study, we enrolled 621 patients within a month of an initial ischemic stroke and followed them regularly twice annually; 198 were diabetic. We monitored blood glucose level in 142 (72%) using glycosylated hemoglobin (HbAlc). Recurrent stroke frequency was determined by history, examination, and medical records. Cox proportional hazards models were used to examine the relationship between risk of recurrent stroke and HbAlc level. The models included interaction with time-dependent HbAlc level and history of diabetes, selected medical comorbidities, age, and sex. HbAlc level was analyzed as both a continuous and a dichotomous variable (ie, controlled versus uncontrolled); "controlled" was defined with different cut points. RESULTS: All but 17 patients (12%) whose blood glucose was monitored were well controlled (HbAlc < 8%). HbAlc level was not associated with increased risk of stroke recurrence (hazard ratio [HR], 0.87 per 1% increment in HbAlc; 95% confidence interval [CI], 0.623 to 1.219), nor was there a trend toward increased risk of recurrent stroke as the cut point defining "controlled" increased: with HbAlc at < 6%, the HR for the uncontrolled group was 0.51 (95% CI, 0.176 to 1.503); at < 7%, it was 0.43 (95% CI, 0.089 to 1.923); and at < 8%, it was also 0.43 (95% CI, 0.057 to 3.317). CONCLUSIONS: Among diabetic patients with an initial stroke, no association between HbAlc level over time and risk of stroke recurrence was found. However, most patients in this cohort were well controlled, and any adverse effect of poor control could not be adequately tested.

Aged↗
PubMed1996

Molecular cloning and disease association of hepatitis G virus: a transfusion-transmissible agent.

An RNA virus, designated hepatitis G virus (HGV), was identified from the plasma of a patient with chronic hepatitis. Extension from an immunoreactive complementary DNA clone yielded the entire genome (9392 nucleotides) encoding a polyprotein of 2873 amino acids. The virus is closely related to GB virus C (GBV-C) and distantly related to hepatitis C virus, GBV-A, and GBV-B. HGV was associated with acute and chronic hepatitis. Persistent viremia was detected for up to 9 years in patients with hepatitis. The virus is transfusion-transmissible. It has a global distribution and is present within the volunteer blood donor population in the United States.

Acute Disease↗
PubMed1996

A treatment and withdrawal trial of besipirdine in Alzheimer disease.

Besipirdine hydrochloride (HP 749) is an indole-substituted analog of 4-aminopyridine. Besipirdine enhances both cholinergic and adrenergic neurotransmission in the central nervous system. The present study examined the efficacy and tolerability of two doses of besipirdine (5 and 20 mg b.i.d.) in 275 patients with Alzheimer disease during 3 months of treatment and for 3 months after withdrawal of treatment. Assessment after withdrawal of treatment was used in an effort to distinguish persistent efficacy attributable to a neuroprotective mechanism from reversible symptomatic efficacy. Besipirdine was generally well tolerated. The level of performance on the cognitive subscale of the Alzheimer Disease Assessment Scale (ADAS-Cog) was sustained during 3 months of treatment with besipirdine, whereas some deterioration in the performance of patients treated with placebo was observed over the same period. The small difference between active and placebo treatment groups approached, but did not reach statistical significance in the primary intent-to-treat analysis (p = 0.067); analysis of patients who completed all assessments was supportive (p = 0.031). Global ratings using the Clinician Interview-Based Impression of Change did not detect a besipirdine treatment benefit, possibly because of an adverse effect on mood and behavior in some patients. A high ratio of adrenergic to cholinergic potency may have resulted in the adverse effects of besipirdine and hence its failure to support the hypothesis that multiple neurotransmitter treatment may be more efficacious than monotherapy. The efficacy apparent on the ADAS-Cog after 3 months of treatment did not persist 3 months after withdrawal of treatment, suggesting that the benefit was symptomatic. This study provides a practical example of the use of treatment withdrawal assessment to distinguish neuroprotective from symptomatic efficacy.

Aged↗
PubMed1995

Transesophageal echocardiography in diagnosing cardioembolic stroke.

Stroke is a disease with high morbidity and mortality that afflicts older people. The most common type of stroke is ischemic, and 15-20% of these strokes are cardioembolic. Because clinical features are not very specific for the type of stroke, diagnostic aides are needed to identify the mechanism of stroke so that appropriate therapy can be initiated. Numerous studies have shown that transesophageal echocardiography (TEE) is a more sensitive tool for diagnosing cardioembolic stroke than transthoracic echocardiography (TTE). However TTE and TEE are still considered complementary as they both provide unique information. The many abnormalities that can be identified by TEE and their therapy are discussed in this review, along with indications and complications of TEE. TEE has demonstrated that cardioembolic causes of stroke are much more common than previously thought. With a more precise diagnosis, appropriate therapy can be provided to help prevent cardiogenic stroke.

Cerebrovascular Disorders↗
PubMed1995

Prognosis for survival after an initial stroke.

BACKGROUND AND PURPOSE: We studied prognosis for survival after an initial stroke in 662 patients who survived at least 30 days after onset while taking into account age, sex, the number of neurological deficits from the initial stroke, stroke type, and five selected medical conditions: hypertension, myocardial infarction, cardiac arrhythmia, diabetes mellitus, and history of transient ischemic attacks. METHODS: All patients were enrolled between July 1, 1987, and August 1, 1989, and were followed regularly at about 6-month intervals until death or the end of the study (mean of 24 months). RESULTS: At 6 months, 90.8% of the 30-day stroke survivors were still alive. At 1, 2, 3, and 4 years, the cumulative survival rates were 86.9%, 78.7%, 73.2%, and 72.0%, respectively. Older age and the number of neurological deficits at onset of initial stroke increased risk of death. Compared with patients of the same age, sex, number of neurological deficits, and comorbidities, increased risk of death is present among those with myocardial infarction, cardiac arrhythmia, and diabetes mellitus. Hazard ratios were 1.7 (P = .006), 1.5 (P = .023), and 1.4 (P = .059), respectively. Hypertension and transient ischemic attacks were not significantly associated with increased mortality. CONCLUSIONS: This study clarifies prognosis for survival after an initial stroke by taking into account other confounding variables that could also contribute to risk of death.

Age Factors↗
PubMed1994

Black-white differences in stroke frequency: challenges for research.

Studies of ethnic differences in frequency of disease can sometimes provide insights into etiologic mechanisms and, hopefully, lead to interventions that decrease risk and frequency of the disease. This principle can be applied to studies of stroke among blacks and whites. Blacks carry a disproportionate burden of strokes relative to the number of blacks in the population. In this paper, possible explanations for the differences are reviewed. It has been reported that certain risk factors for stroke, notably hypertension, are more common in blacks. However, it is unclear whether less access to medical care, difficulty with compliance in treatment programs, genetic differences in responsiveness to certain drugs or other genetic differences related to susceptibility are responsible for the consistently higher stroke frequency in blacks compared to whites. The frequency of stroke type also differs in these ethnic groups; whites are more prone to large vessel and embolic strokes whereas blacks suffer a higher frequency of small vessel and hemorrhagic stroke. When closely examining evidence, it is also unclear whether life-style, socioeconomic, or other factors can be implicated and even whether race plays any important role at all. All of these ethnic issues must carefully be considered in stroke data base research.

Black People↗
PubMed1994

A multifactorial analysis of risk factors for recurrence of ischemic stroke.

BACKGROUND AND PURPOSE: Risk factors for stroke recurrence have usually been evaluated as single variables. This study is a multivariate analysis of five risk factors (hypertension, myocardial infarction, cardiac arrhythmia, diabetes mellitus, and transient ischemic attacks) for second stroke after an initial ischemic stroke. METHODS: Six hundred twenty-one patients with an acute ischemic stroke were followed prospectively first at 4 months after onset and then at approximately 6-month intervals until death, recurrence of stroke, or the end of the study. The five risk factors were measured at each visit. A Cox multifactorial regression analysis was conducted using the risk factor status at enrollment and adjusted for age and sex. RESULTS: Follow-up averaged 24 months (range, 1 to 48 months). Men comprised 52% of the cohort and were slightly older; 97% of the cohort was white, and 57% had multiple risk factors. Hypertension occurred in 59%, cardiac arrhythmia in 47% (of which 16% had atrial fibrillation), diabetes mellitus in 30%, myocardial infarction in 25%, and transient ischemic attacks in 18%. Only history of hypertension and atrial fibrillation by electrocardiogram were associated with increased risk of second stroke independently and significantly (P = .01 and P = .04, respectively). CONCLUSIONS: Among the five factors analyzed, control of hypertension and atrial fibrillation appear to offer the greatest chance of reducing risk of stroke recurrence after an ischemic stroke.

Aged↗
PubMed1994

Hypertension and risk of stroke recurrence.

BACKGROUND AND PURPOSE: Hypertension is a risk factor for initial stroke, but its relation to stroke recurrence is unclear. Therefore, we sought to analyze the effect of hypertension and its control on risk of stroke recurrence. METHODS: Within 1 month of onset, a population-based cohort of 662 patients from the Lehigh Valley with an initial stroke were enrolled. Hypertension was determined at enrollment by history. Blood pressure was also measured at enrollment and at each follow-up at 4- to 6-month intervals for up to 48 months (mean, 24 months). Stroke recurrence was verified by history, examination, and review of medical reports. Various criteria for control of blood pressure were defined. History of hypertension, measured blood pressure, and its control were analyzed in relation to stroke recurrence frequency using Kaplan-Meier and univariate, multivariate, and time-dependent Cox proportional hazards models. RESULTS: At enrollment, 59.4% of the cohort had a history of hypertension and 81 patients had a second stroke. Those with a history of hypertension had a significantly higher stroke recurrence rate than those without such a history (P = .01). Among those with measured diastolic blood pressure at enrollment > or = 95 mm Hg, 43% had a stroke recurrence by the end of the study compared with only 19% below this cutoff (P = .005). Recurrence risk was reduced in a multivariate analysis as quality of diastolic blood pressure control increased (relative risk = 8.4, 3.9, and 2.0 among those with poor, fair, and good control, respectively, compared with nonhypertensive subjects). Systolic blood pressure and its control appeared less or not significantly associated with stroke recurrence. CONCLUSIONS: History of hypertension and elevated measured diastolic pressure after the initial stroke were associated with an increased risk of second stroke. Controlling diastolic pressure substantially reduced this risk.

Age Factors↗