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Biomedical subjects

S W Parker

Publications and source records attributed to S W Parker.

At least 19 recordsLinked to original sources
PubMed2004

Origins and consequences of the elongation of the human menstrual cycle during the menopausal transition: the FREEDOM Study.

The menopausal transition is characterized by the appearance of elongated cycles, which become longer and more frequent as menopause approaches. Several endocrine abnormalities have been attributed to these cycles; however, no quantitative studies of their causes and consequences exist to date. This study is based on sequential daily urinary concentrations of FSH, LH, estrone 3-glucuronide (E1G), and pregnanediol 3-glucuronide (PdG) from 34 women with perimenopausal menstrual irregularity (total of 289 cycles). The timing of ovarian response was determined as the day of E1G take-off (ETO). Other parameters measured were the mean FSH concentration before ETO (FSH(ETO)) and the midluteal levels of PdG, E1G, and LH. There was a strong parallelism between ETO and cycle length variability. FSH(ETO) levels increased gradually with ETO. Both ETO and FSH(ETO) were inversely related to luteal PdG and directly related to E1G. PdG and LH levels were inversely related. All comparisons were highly significant (P < 0.0001). We conclude that delayed ovarian response underlies the elongation of the menstrual cycle in the menopausal transition, which is likely to be caused by a temporary lack of ovarian responsiveness to FSH. A progressive decline in luteal PdG with increased E1G occurs in association with these trends.

Adult↗
PubMed2004

Relationship between follicle-stimulating hormone levels at the beginning of the human menstrual cycle, length of the follicular phase and excreted estrogens: the FREEDOM study.

Although reproductive aging has been separately related to elevated FSH and shorter follicular phase (FP), the direct association between both parameters has not been investigated. Also, the exact effects of increased FSH on estrogen production are yet to be established.A large database of daily urinary concentrations of FSH, LH, and estrone 3-glucuronide (E1G) from 37 regularly menstruating women (median 11 cycles per patient) was used. Initial FSH levels (iFSH) were estimated as the mean value of d 1-5. The day of E1G take-off (ETO) was determined by an algorithm, and accordingly, the FP was divided into early (d 1 to ETO) and late (ETO+1 to LH peak). FP maximum and integrated E1G were calculated. Subjects were distributed according to their mean iFSH into three categories (</=5, >5 to 10, and >10 IU/liter). There was a gradual decrease in FP length with increasing category (15.2 +/- 3.8, 14.1 +/- 3.6, and 13 +/- 2.6 d, respectively; P < 0.0001). A similar effect occurred in early FP (7.5 +/- 4, 6.4 +/- 3.7, and 5.4 +/- 2.7; P < 0.0001); in contrast, late FP was unaffected (7.7 +/- 2.1, 7.7 +/- 2.1, and 7.6 +/- 2.4; P = 0.86). No consistent increase in E1G was found with advancing iFSH category; however, women with mean initial LH higher than 6 IU/liter had significantly elevated maximum (P < 0.0001) and integrated (P = 0.002) E1G.FP length decreases in parallel with increasing iFSH, with a selective effect on the early FP. Increased FSH does not affect E1G; however, elevated initial LH level was related to higher E1G.

Adult↗
PubMed2000

Quality of care and temperament determine changes in cortisol concentrations over the day for young children in childcare.

The current study investigated whether patterns of cortisol production in preschool-aged children in group care were influenced by characteristics such as group size, adult:child ratio, separation from family/parents, and quality of attention and stimulation from the childcare provider. Data were obtained from preschoolers attending home-based childcare. Cortisol levels were sampled at home and at childcare. Parents and teachers assessed the child's temperament (CBQ, TBQ). At childcare, the children were observed using the Observational Ratings of the Caregiving Environment (ORCE). Childcare characteristics were independent of family or child characteristics. In home-based childcare, children's cortisol patterns over the day correlated significantly with the amount of attention and stimulation provided by the childcare provider. Using a median split on the quality index measure of focused attention/stimulation, children in settings that were above the median exhibited no change in cortisol from home to childcare, while those in settings below the median exhibited a reversal of the typical pattern of cortisol production from morning to afternoon. At home these children exhibited the expected decrease in cortisol from morning to afternoon. Patterns of cortisol production at childcare were also correlated with child temperament with larger increases from morning to afternoon for more emotionally negative children and those with less self-control. Finally, cortisol production in home-based childcare was compared to data from children in center-based childcare and children not enrolled in full-day childcare.

Attention↗
PubMed1997

Household income and health care expenditures in Mexico.

The purpose of this paper is to examine the determinants of household health expenditures in Mexico. Our analysis involves the estimation of household monetary health care expenditures, using the economic and demographic characteristics of the household as covariates. We pay particular attention to the impact of household income on health expenditures, estimating the elasticity of health care expenditures with respect to income for different income groups and according to health insurance status. For the empirical analysis, we use the Mexican National Survey of Income and Expenditures of 1989. Our principle findings show that monetary health expenditures by Mexican households are sensitive to changes in household income levels and that the group which is most responsive to changes in income levels in the lower-income uninsured group. This suggests that in times of economic crisis, these households reduce cash expenditures on health care by proportionately more than higher-income and insured households.

Data Interpretation, Statistical↗
PubMed1997

Rehabilitation of balance in two patients with cerebellar dysfunction.

The treatment of two patients with cerebellar dysfunction is described. One patient was a 36-year-old woman with a 7-month history of dizziness and unsteadiness following surgical resection of a recurrent pilocystic astrocytoma located in the cerebellar vermis. The other patient was a 48-year-old man with cerebrotendinous xanthomatosis (CTX) and diffuse cerebellar atrophy, and a 10-year history of progressive gait and balance difficulties. Each patient was treated with a 6-week course of physical therapy that emphasized the practice of activities that challenged stability. The patient with the cerebellar tumor resection also performed eye-head coordination exercises. Each patient had weekly therapy and performed selected balance retraining exercises on a daily basis at home. Measurements taken before and after treatment for each patient included self-perception of symptoms, clinical balance tests, and stability during selected standing and gait activities; for the patient with the cerebellar tumor resection, vestibular function tests and posturography were also performed. Both patients reported improvements in symptoms and demonstrated similar improvements on several kinematic indicators of stability during gait. The patient with the cerebellar tumor resection improved on posturography following treatment, whereas the patient with CTX improved on clinical balance tests. This case report describes two individualized treatment programs and documents functional improvements in two patients with different etiologies, durations, and clinical presentations of cerebellar dysfunction. The outcomes suggest that patients with cerebellar lesions, acute or chronic, may be able to learn to improve their postural stability.

Adult↗
PubMed1996

Delayed complications thirty-six years after hemispherectomy: a case report.

PURPOSE: To describe a late complication of hemispherectomy in a patient in whom symptoms of hydrocephalus developed 36 years after her left-sided hemispherectomy, the longest delay on record. METHODS: Hemispherectomy has been successfully used in the treatment of intractable epilepsy associated with infantile-type hemiplegia for a half century. Of the patients, however, up to 33% have late increased cerebrospinal fluid pressure complications attributed to superficial cerebral hemosiderosis. Through a retrospective case analysis, we describe such complications in a 52-year-old woman with cognitive impairment, gait instability, urinary incontinence, and right hemineglect 36 years after her initial procedure. RESULTS: Quantitative, objective measures of cognition and gait-laboratory testing confirmed the patient's favorable clinical response to ventriculoperitoneal shunting, as well as the complete resolution of her symptoms, including the atypical occurrence of right-sided hemineglect. CONCLUSIONS: This case uniquely demonstrates the clinical features of a late complication of hemispherectomy while documenting the longest reported delay for developing such adverse sequelae. We also emphasize the need for more extensive follow-up studies to assess the extent of posthemispherectomy complications.

Brain↗
PubMed1994

Physical therapy management of peripheral vestibular dysfunction: two clinical case reports.

We describe the treatment of two patients with peripheral vestibular dysfunction using a novel, staged exercise program. Response to treatment was documented. The first patient, a 62-year-old woman with unilateral vestibular dysfunction (UVD) and a 6-month history of disequilibrium following herpes zoster oticus resulting in damage to the right inner ear, was treated with an 8-week course of vestibular physical therapy. During the 8 weeks, the patient attended weekly physical therapy sessions and was trained to perform vestibular adaptation exercises on a daily basis at home. The second patient, a 53-year-old woman with progressive disequilibrium secondary to profound bilateral vestibular hypofunction (BVH), was treated with a 16-week course of vestibular physical therapy. During the first 8 weeks, the patient attended weekly physical therapy sessions and was trained to perform vestibular adaptation and substitution exercises on a daily basis at home. During the second 8 weeks, the patient continued performing vestibular physical therapy exercises at home independently. Vestibular function (sinusoidal vertical axis rotation testing), postural control (clinical tests and posturography), stability during the performance of selected activities of daily living (ADLs), and self-perception of symptoms and handicap were measured prior to and at the conclusion of treatment for both patients and at the midpoint of treatment for the patient with BVH. After 8 weeks of treatment, both patients reported improvements in self-perception of symptoms and handicap and demonstrated objective improvements in clinical balance tests, posturography, and several kinematic indicators of stability during the performance of selected ADLs. Further improvements were noted in the patient with BVH after 16 weeks of treatment. Improvements in postural control were noted after 8 weeks of treatment for the patient with UVD and after 16 weeks for the patient with BVH. Vestibular function improved during the course of treatment for the patient with UVD only. These case reports describe two different individualized treatment programs and document self-reported and laboratory-measured functional improvements in two patients with vestibular deficients--one with unilateral damage and one with bilateral damage.

Activities of Daily Living↗
PubMed1993

Double-blind, placebo-controlled trial of rehabilitation for bilateral vestibular hypofunction: preliminary report.

Vestibular rehabilitation (VR) is increasingly popular, but few data exist to support enthusiasts' claims of efficacy in improving functional abilities of patients with bilateral vestibular hypofunction (BVH). A double-blind, controlled study of eight subjects (mean, 64 +/- 12 years; seven females, one male) with bilateral vestibular hypofunction was conducted. Subjects in group A received 8 weeks of VR followed by 8 weeks of home VR exercises, whereas those in group B received 8 weeks of control treatment (isometric strengthening exercises) followed by 8 weeks of VR. At the end of 8 weeks, group A walked 8% faster and, during paced gait and stair-climbing, with greater stability, evidenced by a 10% larger maximum moment arm and a 17% decreased double-support duration during gait and stair stance. Group B improved less than 1% during the control treatment. Self-reported Dizziness Handicap Inventory scores did not differ significantly between control and active VR. All subjects improved compared with baseline tests at the 16-week post-test on both functional testing and on the Self-reported Dizziness Handicap Inventory scale. We conclude that in this small sample, VR effectively improved functional, dynamic stability during locomotion, but even strengthening exercises result in self-reported symptomatic improvement.

Aged↗
PubMed1993

Vestibular evaluation--electronystagmography, rotational testing, and posturography.

This report describes a battery of tests that is utilized by several clinical laboratories to investigate vestibular and balance function. The electronystagmogram evaluates eye movements, inner ear function, brainstem function and cerebellar function. Sinusoidal vertical axis rotation is a sensitive measure of horizontal semicircular canal function that is often complimentary to the caloric stimulation portion of the electronystagmogram. Visual-vestibular interaction rotation testing is designed to evaluate brainstem, cerebellar and oculomotor function. Dynamic posturography facilitates measurement of standing balance and permits a quantification of the role of proprioception, vision and the vestibular system in the maintenance of standing balance.

Adrenocorticotropic Hormone↗
PubMed1991

Abnormal single motor unit behavior in the upper motor neuron syndrome.

We studied the discharge pattern of single motor units (SMUs) in the left and right biceps muscles from a patient with nonspastic weakness of the left arm. Detailed statistical analysis of the behavior of discharge patterns of 4 of 4 single motor units on the affected side showed abnormalities with characteristic features of an upper motor neuron lesion. Five out of 5 single motor units recorded from the right biceps were normal. An upper motor neuron lesion affecting the left arm, predicted by our results, was confirmed by magnetic resonance imaging (MRI), which showed a lesion in the right precentral gyrus. It appears that changes in single motor unit firing characteristics, caused by an upper motor neuron lesion, can be detected at a time when there is no evidence of increased "tone" and/or hyperreflexia (spasticity) in the affected extremity.

Arm↗
PubMed1988

Pharmacokinetics of two multiple-dose mezlocillin regimens.

The pharmacokinetics of mezlocillin at two dosages were studied over the course of therapy in 12 patients receiving the drug for the treatment of infections. Patients received an initial dosing regimen of 4 g every 6 h or 5 g every 8 h, which was switched to the alternative regimen after 5 days of treatment. Both drug regimens demonstrated similar pharmacokinetic characteristics, which suggests that the reported dose-dependent elimination of mezlocillin is not an important factor in the clinical use of mezlocillin at the dosages currently used.

Adult↗
PubMed1987

Pure motor hemiplegia due to meningovascular neurosyphilis.

Two young male homosexuals developed prodromal syndrome followed by penicillin-responsive meningitis and the acute onset of pure motor hemiplegia. The clinical and laboratory features are consistent with meningovascular neurosyphilis. Basis pontis infarctions were subsequently demonstrated on magnetic resonance imaging scans. To our knowledge, this is the first description of syphilitic arteritis as a pathophysiologic basis for pure motor hemiplegia.

Adult↗
PubMed1985

Adenovirus type 2 encephalitis and concurrent Epstein-Barr virus infection in an adult man.

A 30-year-old bisexual male prisoner with a history of intravenous drug abuse manifested encephalitis. Adenovirus type 2 was isolated from brain tissue obtained by a biopsy and there was a concurrent fourfold rise in the antibody titer. In addition, an initial negative result from a slide test for infectious mononucleosis heterophil antibodies (Monospot) test converted to positive and there was an increase in the IgG antibody titer to Epstein-Barr virus (EBV) viral capsid antigen. Although he was anergic to skin test antigens, T-cell subsets and lymphocyte transformation study results were normal. This case demonstrated a rare adenovirus encephalitis with a simultaneous EBV infection in a patient at risk for acquired immunodeficiency syndrome, who had minimal evidence of T-cell deficiency.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Pharmacokinetics of aztreonam in patients with gram-negative infections.

Aztreonam pharmacokinetics were assessed in seven patients treated for urinary (n = 6) or lower respiratory (n = 1) tract infections. Each patient was studied twice, at the beginning and end of therapy (7 to 10 days). The patients enrolled had normal to moderately impaired renal function; a good correlation (r2 = 0.90) between serum aztreonam clearance (CL) and creatinine clearance (CLCR) was observed (mean CL/CLCR ratio = 1.11). CL ranged from 21.6 to 121 ml/min per 70 kg, and the half-life ranged from 1.6 to 8.9 h. The mean steady-state volume of distribution (0.16 +/- 0.05 [standard deviation] liter/kg) approximated the extracellular fluid volume. Protein binding of aztreonam in serum (mean, 30%) was lower than that reported in healthy adults. CL increased significantly from the first to the last day of the study, probably reflecting increasing renal function. After multiple dosing (1 g every 8 h), no significant accumulation of aztreonam was observed. Overall, the disposition of aztreonam is comparable in infected and noninfected subjects, and dosing adjustments in patients with renal impairment should be facilitated by the good correlation between CL and CLCR.

Adult↗
PubMed1983

Circumcision and sexually transmissible disease.

The relationship between circumcision and sexually transmissible disease was studied in 1350 men who attended the Public Health Department Special Treatment Clinic in Perth, Western Australia. Evidence of circumcision was obtained by examination. More than 98% of the men studied gave a verbal report of their circumcision status which was consistent with the examination findings. Eight hundred and forty-eight men had STD; 471 men, who presented to the clinic for diagnosis and treatment but who were found not to have STD, constituted the control group. The results of the study show significant associations between the state of being uncircumcised and four major sexually transmissible diseases--herpes genitalis, candidiasis, gonorrhoea and syphilis. Estimates of the relative risk suggest that uncircumcised men are twice as likely as circumcised men to develop herpes genitalis or gonorrhoea, and five times as likely to develop candidiasis or syphilis. However, the data for syphilis should be interpreted with caution because of the small number of cases. No significant increase in risk was found for any of the other sexually transmissible diseases diagnosed at the clinic.

Adult↗