Oral 1,25-dihydroxyvitamin D administration in osteoporotic women: effects of estrogen therapy.

Estrogen has been shown to modify calcium and skeletal homeostasis. In this study, we tested the ability of estrogen to influence the effects of short-term 1,25(OH)2D administration on biochemical indices of bone formation and resorption in a cross-sectional analysis of untreated (n = 10) and estrogen-treated (n = 14) osteoporotic women. Patients were given oral 1,25(OH)2D (Rocaltrol) 0.

Human processing of colour information in the chromatic-frequency domain.

On the basis of MacAdam's data, we have computed a psychophysical function which characterizes the transference of the colour information processed by the human visual system in the chromatic frequency domain. This function, obtained using chromatic-discrimination criteria, shows a cut-off frequency between 0.01375 and 0.

Teenage and current calcium intake are related to bone mineral density of the hip and forearm in women aged 30-39 years.

The relation between diet and bone mineral density in premenopausal women was evaluated in a cross-sectional study of 139 women aged 30-39 years. The population consisted of volunteers recruited in Rockland County, New York, between September 1988 and August 1992. A food frequency questionnaire was used to determine nutrient intake for both the year prior to bone density measurement and for ages 13-17 years.

High prevalence of vitamin D deficiency and reduced bone mass in multiple sclerosis.

Background: Female patients with multiple sclerosis (MS) are at risk for osteoporosis because of gender, immobility, and corticosteroid use.

Methods: Bone mineral density (BMD) was measured by dual x-ray absorptiometry in 80 female MS patients admitted to a tertiary care hospital. All patients completed a questionnaire that included measurements of dietary intake and sunlight exposure.

High-dose glucocorticoids in multiple sclerosis patients exert direct effects on the kidney and skeleton.

The effects of acute pharmacologic steroid treatment on skeletal and mineral metabolism were assessed in 56 multiple sclerosis patients who were to receive 1 g intravenous methylprednisolone for 10 days, followed by a 4 day intravenous and 28 day oral glucocorticoid taper. Serum and urine samples were obtained at baseline and then within 3 days, 1, 2, and 3 weeks after beginning steroids. A subset of patients (n = 11) had sampling throughout the 6 weeks of steroid administration and up to 8 weeks afterward.

Effects of estrogen on response to edetic acid infusion in postmenopausal osteoporotic women.

We and others have hypothesized that estrogen helps preserve bone mass by affecting the PTH/vitamin D regulation of skeletal metabolism. To evaluate this theory, we tested the effect of estrogen administration on parathyroid sensitivity to hypocalcemic challenge. Subjects were postmenopausal osteoporotic women recruited from a tertiary care clinic (9 untreated and 12 receiving hormone replacement therapy at the time of the investigation).

Subcutaneous administration of the amino-terminal fragment of human parathyroid hormone-(1-34): kinetics and biochemical response in estrogenized osteoporotic patients.

A standard dose (400 U or 25 micrograms) of human (h) PTH-(1-34) was administered sc in 11 estrogen-treated patients with postmenopausal osteoporosis. Increments in circulating hPTH-(1-34) were brisk, peaking at 30 min, with variable peak levels averaging 10 times normal. Clearance of the peptide from the circulation followed an expontential pattern, with a mean t1/2 of 75 min.

Calcium homeostasis of an elderly population upon admission to a nursing home.

Objective: To evaluate the skeletal health, calcium, and vitamin D homeostasis of patients upon their entry to a long-term-care facility. Factors that could contribute to the risk of future osteoporotic fractures were also evaluated.

Design: Cross-sectional study.

Dietary risk factors for the incidence and recurrence of colorectal adenomatous polyps. A case-control study.

Objective: To investigate the association of dietary factors with the incidence and recurrence of colorectal adenomatous polyps.

Design: Two case-control studies.

Setting: Three university-based colonoscopy practices in New York City.

Effect of blood-brain barrier and blood-tumor barrier modification on central nervous system liposomal uptake.

In this study of 25 central nervous system (CNS) tumor-bearing rats, the CNS biodistribution of intravenously administered, indium-labeled liposomes was investigated. In 16 animals, the blood-brain barrier and blood-tumor barrier were modified using intracarotid administration of etoposide. In control animals, analysis by autoradiography and well-counting experiments demonstrated uptake of liposomes in the tumor-bearing hemisphere (% injected dose/g tissue = 0.

Bone mass among premenopausal women.

Bone mass in early adult life, or peak bone mass, is primarily under genetic control, although recent data suggest that alterations in nutrition and life style during growth may modify the genetic potential. Cross-sectional data indicated that upon completion of growth, there was a period of skeletal consolidation that resulted primarily from increased width of cortical bones. Data on cancellous bone are conflicting.

Comparative assessment of bone mineral density of the forearm using single photon and dual X-ray absorptiometry.

Forearm bone mineral density (BMD) was measured at proximal and distal sites by 125I single photon absorptiometry (SPA) and by dual energy X-ray absorptiometry (DXA) in 67 consecutive subjects, aged 18-75 years. Correlations and regression equations between these two techniques were determined. All forearm measurements were significantly correlated with each other (r = 0.

A case-control study of hip fracture: evaluation of selected dietary variables and teenage physical activity.

Recent diet, teenage physical activity and teenage calcium consumption were examined as risk factors for hip fracture in a case-control study. Cases were 161 white women admitted to one of 30 participating hospitals with a first hip fracture. Controls included 168 white women from general and orthopedic surgical services frequency-matched to cases by age group and hospital.

The effect of graded spinal cord injury on the extrapyramidal and pyramidal motor evoked potentials of the rat.

This study investigated the differential effects of graded spinal cord injury on the rat extrapyramidal motor evoked potential (exp-MEP) and pyramidal motor evoked potential (pyr-MEP) and the prognostic value of these effects in predicting postinjury motor performance in the rat model. In 20 rats subjected to graded spinal injury (10-100 g-cm), there was a differential injury threshold for ablation of exp-MEP and pyr-MEP. All peaks of the pyr-MEP were extinguished in the animals subjected to impact forces of 50 g-cm and above (n = 12).

EEG coherence as a predictor of spike propagation.

The relationship between resting EEG coherence and the propagation of spike activity from an experimental cortical focus was investigated in 6 rats. EEG was collected from an array of 6 epicortical electrodes positioned over the posterior hind limb sensorimotor (HL) and frontal (Fr1, Fr2) cortices. Coherence decreased non-linearly for all frequency bands with increasing interelectrode distance.