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Biomedical subjects

E E Marsh

Publications and source records attributed to E E Marsh.

14 recordsLinked to original sources
PubMed2000

Decrease in gonadotropin-releasing hormone (GnRH) pulse frequency with aging in postmenopausal women.

UNLABELLED: Increasing evidence suggests that aging is associated with dynamic changes in the hypothalamic and pituitary components of the reproductive axis that are independent of changes in gonadal hormone secretion. This study was designed to determine the effect of age on GnRH pulse frequency in women in the absence of gonadal feedback using gonadotropin free alpha-subunit (FAS) and LH as neuroendocrine markers of endogenous GnRH secretion. All studies were performed in healthy, euthyroid postmenopausal women (PMW) during daytime hours. The impact of sampling interval and duration on assessment of pulse frequency in PMW was first examined in 10 women with a mean age of 61.6 +/- 8 yr (mean +/- SD), in whom blood was sampled every 5 min for 12 h. Each 5-min series was then reduced to simulate a 10-min series and then a 15-min series for pulse analysis, and the effect of 8 h compared with 12 h of sampling was determined. To define the changes in the frequency and amplitude of pulsatile hormone secretion with aging, 11 younger (45-55 yr) and 11 older (70-80 yr) PMW were then studied over 8 h at a 5-min sampling interval. In the initial series, the mean interpulse intervals (IPIs) for FAS were 53.8 +/- 3.6, 69.2 +/- 3.9, and 87.6 +/- 7.3 min at sampling intervals of 5, 10, and 15 min, respectively (P < 0.0005). The LH IPI also increased progressively with sampling intervals of 5, 10, and 15 min (54.4 +/- 2.5, 70.4 +/- 2.3, and 91.1 +/- 4.4 min; P < 0.0001). At the 5-min sampling interval, the calculated number of pulses/24 h was not different between a 12-h series compared with an 8-h series for either FAS or LH. In the second series of studies, the older PMW had lower gonadotropin levels (LH, 86.5 +/- 8.8 vs. 51.3 +/- 7.7 IU/L, P < 0.01; FSH, 171.6 +/- 16.9 vs. 108.2 +/- 10.5 IU/L, P < 0.005; FAS, 1021.5 +/- 147.4 vs. 425.6 +/- 89.6 ng/L, P < 0.005, in younger and older PMW, respectively) despite no differences in estrone or estradiol levels. The older PMW also demonstrated a slower FAS pulse frequency compared with their younger counterparts, as reflected in an increased FAS IPI (52.6 +/- 3.1 and 70.6 +/- 5.9 min; P < 0.002). The difference in IPIs between younger and older PMW was not statistically significant for LH (65.4 +/- 5.6 and 71.8 +/- 6.6 min for younger and older PMW, respectively). FAS pulse amplitude was decreased in older PMW compared with younger PMW (431.7 +/- 66.2 vs. 224.6 +/- 81.9 ng/L; P < 0.01), whereas the decrease in LH pulse amplitude with age was of borderline statistical significance (23.2 +/- 3.1 vs. 15.9 +/- 2.1 IU/L; P = 0.09). IN CONCLUSION: 1) the use of a 5-min sampling interval and measurement of FAS as the primary marker of GnRH pulse generator activity indicate that GnRH pulse frequency in younger PMW is faster than previously reported, but not increased over that seen in the late follicular phase and midcycle surge in women with intact ovarian function; and 2) the marked decrease in FAS pulse frequency with age provides evidence of age-related changes in the hypothalamic component of the reproductive axis that are independent of changes in gonadal function.

Activity Cycles↗
PubMed1999

Free alpha-subunit is superior to luteinizing hormone as a marker of gonadotropin-releasing hormone despite desensitization at fast pulse frequencies.

A pulsatile pattern of GnRH stimulation is essential for normal secretion of luteinizing hormone (LH), while both continuous and fast-frequency GnRH stimulation result in a paradoxical decrease in gonadotrope responsiveness known as desensitization. Under physiological conditions there is striking concordance between the pulsatile secretion of LH and the glycoprotein free alpha-subunit (FAS). The aims of this study were to determine whether the FAS response to GnRH is also decreased at fast frequencies of GnRH stimulation and whether FAS is superior to LH as a marker of GnRH secretory activity at fast-pulse frequencies. The model of GnRH-deficient men was chosen to permit precise control of the dose and frequency of GnRH stimulation of the gonadotrope. The frequency of i.v. administration of GnRH to 5 GnRH-deficient men was progressively increased from every 120 to every 60 min, from 60 to 30 min, and from 30 to 15 min during three 12-h admissions, 1 week apart. The bolus dose of GnRH remained constant and was set at that dose previously shown to produce physiological concentrations and amplitudes of LH secretion and normal testosterone levels. As the frequency of GnRH stimulation was increased, a progressive rise in mean FAS levels was noted (353 +/- 13, 448 +/- 42, 466 +/- 50, and 698 +/- 85 ng/L [mean +/- SEM] for 120, 60, 30, and 15 min intervals; P < 0.005). However, normalization of mean FAS levels to account for the increase in total GnRH delivered with increasing frequencies revealed a progressive decrease in pituitary responsiveness to each GnRH bolus with increasing frequency of stimulation (353 +/- 13, 224 +/- 21, 117 +/- 13, 87 +/- 11 ng/L; P < 0.001). The decrease in normalized mean levels was supported by a decrease in the FAS pulse amplitude with increasing frequency (517 +/- 53, 365 +/- 50, 176 +/- 29 ng/L for 120, 60, and 30 min intervals, respectively; P < 0.005). At interpulse intervals of 120 and 60 min, there was complete concordance of LH and FAS pulses in response to GnRH. However, at the 30-min frequency FAS proved to be a better marker of GnRH with a higher true positive rate and lower number of false positives than LH (P < 0.05). At all frequencies, the number of false positive pulses detected tended to be lower for FAS than for LH (P = 0.06). From these data we conclude that FAS is subject to desensitization in response to increasing frequencies of GnRH administration in GnRH-deficient men, but is superior to LH as a surrogate marker of GnRH pulse generator activity at fast pulse frequencies.

Adult↗
PubMed1993

Classification of subtype of acute ischemic stroke. Definitions for use in a multicenter clinical trial. TOAST. Trial of Org 10172 in Acute Stroke Treatment.

BACKGROUND AND PURPOSE: The etiology of ischemic stroke affects prognosis, outcome, and management. Trials of therapies for patients with acute stroke should include measurements of responses as influenced by subtype of ischemic stroke. A system for categorization of subtypes of ischemic stroke mainly based on etiology has been developed for the Trial of Org 10172 in Acute Stroke Treatment (TOAST). METHODS: A classification of subtypes was prepared using clinical features and the results of ancillary diagnostic studies. "Possible" and "probable" diagnoses can be made based on the physician's certainty of diagnosis. The usefulness and interrater agreement of the classification were tested by two neurologists who had not participated in the writing of the criteria. The neurologists independently used the TOAST classification system in their bedside evaluation of 20 patients, first based only on clinical features and then after reviewing the results of diagnostic tests. RESULTS: The TOAST classification denotes five subtypes of ischemic stroke: 1) large-artery atherosclerosis, 2) cardioembolism, 3) small-vessel occlusion, 4) stroke of other determined etiology, and 5) stroke of undetermined etiology. Using this rating system, interphysician agreement was very high. The two physicians disagreed in only one patient. They were both able to reach a specific etiologic diagnosis in 11 patients, whereas the cause of stroke was not determined in nine. CONCLUSIONS: The TOAST stroke subtype classification system is easy to use and has good interobserver agreement. This system should allow investigators to report responses to treatment among important subgroups of patients with ischemic stroke. Clinical trials testing treatments for acute ischemic stroke should include similar methods to diagnose subtypes of stroke.

Anticoagulants↗
PubMed1991

Cerebral infarction in patients with nephrotic syndrome.

We describe two adult patients who presented with acute cerebral infarction and were found to have a hypercoagulable state due to nephrotic syndrome. One patient had a deficiency of free protein-S. The other patient had a pulmonary embolus 4 months after the stroke. Our cases demonstrate that the hypercoagulable state associated with nephrotic syndrome can be associated with cerebral arterial thrombosis and infarction in adults. Examination of the urine remains an important part of the evaluation of patients with recent stroke. The presence of severe proteinuria and a low serum albumin content should prompt consideration of a hypercoagulable state. Our experience suggests that anticoagulant drugs may be required to reduce the risk of new thrombotic events.

Adult↗
PubMed1991

Mortality in acute cerebral infarction in young adults--a ten-year experience.

We reviewed the one-month mortality among 213 patients aged fifteen to forty-five years (mean thirty-five) with acute cerebral infarction (CI) evaluated during the period July 1, 1977, to February 1, 1988. Atherosclerotic cerebral infarction (ACI) was diagnosed in 59 (27.7%) patients, 53 (24.9%) had non-atherosclerotic vasculopathies (NAV); 46 (21.6%) had cardioembolic infarcts (CEI). Hematologically related disorders were diagnosed in 30 (14.1%) patients; the cause of CI could not be established in 25 (11.7%) patients. Fourteen patients (9 men, 5 women, mean age 34.8 years), (6.6%) died within thirty days of their CI: 7 had CEI (7/46,15.2%); 4 had ACI (4/59, 6.7%); and 3 had NAV (3/53, 5.6%). Our data suggest that young patients with acute CI have a thirty-day mortality rate lower than older patients. Deaths were most common in patients with CEI. Brain edema and herniation accounted for 6 (43%) of the deaths.

Acute Disease↗
PubMed1990

Circadian variation in onset of acute ischemic stroke.

A circadian pattern for the onset of myocardial and cerebral infarction has been identified. To evaluate this phenomenon further, we analyzed prospectively collected data from 151 patients with acute ischemic stroke. The number of strokes per 6-hour period were the following: midnight to 6 AM, 20 (13%); 6 AM to noon, 86 (57%); noon to 6 PM, 21 (14%); and 6 PM to midnight, 24 (16%). This pattern was not affected by previous use of aspirin. The most frequent time of onset was 6 AM to noon for all subgroups of ischemic stroke: small artery, 71%; cardioembolic, 62%; large artery atherothrombotic, 57%; large artery atheroembolic, 46%; and "other" or unknown cause, 40%. We also investigated the time between awakening and stroke onset in 145 patients and found that 24% of ischemic strokes occurred within the first hour after awakening. Our data demonstrate that an early morning peak exists for all subtypes of stroke. Our data also suggest that the most critical period is the first hour after awakening.

Acute Disease↗
PubMed1990

Spontaneous improvement after acute ischemic stroke. A pilot study.

Recent clinical studies emphasize the importance of early (less than 12 hours after onset) treatment of patients with acute ischemic stroke. Therapies have been proposed as being effective because of early clinical improvement. The frequency and degree of spontaneous improvement in such patients, however, is unknown. We prospectively evaluated the course of 29 patients (19 men, 10 women) aged 33-82 years who were seen less than or equal to 12 hours after the onset of acute ischemic stroke. Seventeen patients were first evaluated less than or equal to 6 hours and the remaining patients at 6-12 hours after onset. All patients were examined using a modified National Institutes of Health Stroke Scale at baseline, 1, 2, 3, and 6 hours. No specific treatment for acute ischemic stroke was given during this time. Improvement (defined as a decrease of greater than or equal to 2 points from baseline score) was noted at 1 hour in seven patients (24%). By 6 hours 15 patients (52%) had improved, 12 (41%) were unchanged, and two (7%) were worse. Our results suggest that spontaneous, often dramatic improvement occurs in patients with acute ischemic stroke and should be taken into consideration in the design of any trial of acute treatment.

Adult↗
PubMed1989

Etiology of stroke in patients with Wernicke's aphasia.

We reviewed 49 patients with Wernicke's aphasia resulting from a stroke. Their aphasia was classified on the basis of comprehensive neuropsychological testing. Wernicke's aphasia was more common in older patients and in men. Cerebral infarction occurred in 38 patients (78%) and intracerebral hemorrhage in seven (14%); the remaining four patients (8%) developed aphasia after surgery for aneurysmal subarachnoid hemorrhage. Embolic events were the most common etiology of Wernicke's aphasia in the 38 patients with cerebral infarction, with cardiac emboli in 40% and large-vessel atheroemboli from a carotid source in 16%. In patients with Wernicke's aphasia secondary to infarction, an embolic source should be sought. Patients with Wernicke's aphasia should have computed tomography to exclude intracerebral hemorrhage before institution of anticoagulant therapy.

Adult↗
PubMed1989

Use of antithrombotic drugs in the treatment of acute ischemic stroke: a survey of neurologists in practice in the United States.

In an attempt to determine the opinions and practices of neurologists regarding the use of antithrombotic drugs in the treatment of acute ischemic stroke, we conducted a survey of 349 randomly selected neurologists from throughout the United States. Responses were received from 247 (71%), and 219 identified themselves as primary or consulting physicians for patients with acute ischemic stroke. During the previous 12 months, these 219 physicians estimated that they had seen a total of 14,636 patients within 24 hours of acute ischemic stroke, and 22% of these patients were treated with heparin. The most frequently reported indications were prevention of recurrent cerebral embolism (82% of physicians) and progressing stroke (70%). Despite the frequent use of heparin, only 6.4% of neurologists felt that it has been shown to be effective, and 16.4% felt that it has been shown to be of no value. The primary concern about the use of heparin was lack of proven efficacy in 48% and safety concerns in 41%. Results of a future trial testing the efficacy of antithrombotic drugs would be useful for most neurologists in their management of patients with acute or progressing ischemic stroke.

Acute Disease↗
PubMed1985

Incidence of seizures with tricyclic and tetracyclic antidepressants.

One hundred eighty-six depressed psychiatric inpatients were seen at our institution during 1982. Forty-five of these patients were treated with tricyclic antidepressants, 32 received maprotiline hydrochloride, a tetracyclic compound, 20 received other medications, and 82 received no drug treatment. One patient in the tricyclic group (2.2%) and five patients in the maprotiline group (15.6%) developed seizures. In four patients the seizure followed the institution of maprotiline therapy by less than three weeks. These data indicate that depressed patients taking the tetracyclic drug maprotiline are at risk for developing epileptic seizures.

Adult↗
PubMed1982

The site of the lesion in acute deafness of multiple sclerosis--contribution of the brain stem auditory evoked potential test.

Two patients with multiple sclerosis experienced acute unilateral deafness during an exacerbation. The brain stem auditory evoked potential test (BAEP) of both patients revealed absence of all waves after wave I, on the side of the hearing loss. These findings strongly suggest that acute hearing loss in multiple sclerosis results from involvement of the eighth nerve close to the ponto-medullary junction.

Adult↗
PubMedDate not supplied

MR imaging of spinal cord and vertebral body infarction.

PURPOSE: To study the usefulness of MR in the evaluation of spinal cord infarctions and associated findings. MATERIALS AND METHODS: MR examinations of 12 patients (10 men and two women) were reviewed retrospectively. Onset of symptoms of spinal cord ischemia was abrupt in all patients; MR was performed 8 hr to 4 months after onset. Contrast-enhanced MR was performed in four of the patients. RESULTS: Abnormal MR findings of the spinal cord included abnormal cord signal (11 of 12), best demonstrated on T2-weighted images, and morphologic changes (cord enlargement during the acute phase in nine patients and cord atrophy during the chronic phase in two), best demonstrated on T1-weighted images. Vascular abnormalities (aortic) were detected by MR in four of the 12 patients. Three of these four patients also had abnormal bone marrow signal, predominantly in the anterior half (one) or in multiple areas near the endplate and/or deep medullary portion of the vertebral body involving several vertebrae (two). T1-weighted images were not sensitive in detecting signal changes in either the bone marrow (two of three) or spinal cord (nine of 12). Enhanced MR imaging was performed in four patients (two in the acute phase and two in the chronic phase) and showed diffuse enhancement of the spinal cord proximal to a relatively unenhancing distal conus in one of the two patients imaged during the acute phase. No abnormal enhancement was noted in the other three patients. CONCLUSION: MR is a useful means of detecting spinal cord infarction and associated vascular and bony changes. The patterns of bone marrow abnormalities reflect the underlying pathophysiology of the blood supply to the spinal cord and bone. The associated vascular and bone marrow abnormalities serve as additional information for the diagnosis of spinal cord infarction.

Adolescent↗
PubMedDate not supplied

Prophylaxis for thromboembolism in elective orthopaedic surgery.

Thromboembolism is a major complication for patients undergoing elective hip and knee surgery. It can delay full recovery and increase the cost of treatment. This review article focuses on the pathophysiology, risk factors, and methods of prophylaxis in this select patient group. Emphasis is placed on the role of the nurse in the ongoing assessment of the patient's risk for thromboembolism.

Adult↗