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Biomedical subjects

D Press

Publications and source records attributed to D Press.

8 recordsLinked to original sources
PubMed1996

Toxic Releases from Paper Made with Recovered Wastepaper versus Virgin Wood Fiber: A Research Note

Toxic Release Inventory (TRI) data were used to compare average releases (kilograms per metric ton) of paper mills using primarily recovered wastepaper versus mills using primarily virgin wood fiber. Annual releases, for 79 mills, of chlorine, chlorine dioxide, chloroform, acids (hydrochloric and sulfuric), volatile organics (methyl ethyl ketone, methanol, and acetone), and ammonia were compared over the years 1987-1992. Both types of mills reported generally lower toxic releases in 1992 than in 1987; however, toxic releases in all categories were significantly lower from mills using recovered wastepaper than from mills using virgin wood fiber, strongly demonstrating that recycling has added benefits beyond reduced resource consumption. These results suggest that environmental policy should concentrate as much on increasing demand for recycled paper and developing wastepaper collection infrastructure as it does on end-of-pipe pollution abatement.KEY WORDS: Recycled paper; Toxic Release Inventory

Journal Article↗
PubMed1989

Effects of hypophysectomy and ovariectomy on hepatic estrogen receptor content in the turtle, Chrysemys picta.

Estrogen receptor (ER) content in the cytosol and nuclear extract of the liver of adult female Chrysemys picta (control females) was measured in February, May, early June, and late June. Both cytosolic (C) and nuclear (N) hepatic ER content rose from low levels (C: 189 +/- 19; N: 52 +/- 23 fmol/g tissue) in February to significantly higher levels in May (C: 437 +/- 15; N: 124 +/- 25 fmol/g tissue) before declining to lower values in early June (C: 298 +/- 19; N: 118 +/- 20 fmol/g tissue) and late June (C: 274 +/- 22; N: 89 +/- 13 fmol/g tissue). This pattern of seasonal variation in hepatic ER content was also observed in gonadectomized females. Levels of hepatic ER content in ovariectomized turtles fluctuated in the same manner as those found in control females. However, elevations in hepatic ER contents were not observed in hypophysectomized females. Removal of the pituitary resulted in a drastic reduction in the May value (316 +/- 49 fmol/g tissue) of cytosolic ER content and a complete blockade in a rise of nuclear ER content in the liver of the turtle. Nuclear hepatic ER content remained at around 50 fmol/g tissue throughout the months of May and June. The two surgeries procedures caused no significant changes in the ER's affinity for estrogen. The present findings demonstrate a direct control of the pituitary over hepatic ER content which signifies important pituitary regulation of the vitellogenic process, at the liver level, during the spring reproductive season.

Animals↗
PubMed1988

High-affinity binding of [3H]estradiol-17 beta by an estrogen receptor in the liver of the turtle.

Specific [3H]estradiol-17 beta ([3H]E2) binding activity (EBA) with characteristics of an estrogen receptor (ER) was demonstrated in cytosols and nuclear extracts of the female turtle, Chrysemys picta. Three different receptor assays (dextran-coated charcoal assay, hydroxylapatite batch procedure, and DNA-cellulose chromatography) were evaluated in terms of their applicability in analyzing large numbers of samples. For the measurement of cytosolic EBA, the hydroxylapatite batch procedure was found to be the most reliable assay. On the other hand, the dextran-coated charcoal assay was found to be the most appropriate method for the measurement of nuclear EBA. Turtle hepatic EBA binds [3H]E2 with high affinity (cytosolic, 17.4 +/- 2.8 X 10(9) M-1; nuclear, 17.7 +/- 1.9 X 10(9) M-1), limited capacity (cytosolic, 133.7 +/- 4.6 fmol/g tissue; nuclear, 81.1 +/- 9.0 fmol/g tissue), and strict steroid specificity. The EBA bound natural estrogens (E2, estrone, estriol) as well as the nonsteroidal estrogen, diethylstilbestrol, but exhibited little affinity for androgens, progesterone, or corticosterone. The turtle hepatic EBA resembled mammalian and avian ERs in terms of binding characteristics; however, unlike mammalian and avian ERs it was shown to be heat-labile. Incubation at 30 degrees caused rapid loss of [3H]E2 binding activity in both cytosolic and nuclear fractions. The exchange between [3H]E2 and the endogenously bound estrogen was slow at 4 and 15 degrees, but the exchange process was facilitated in the presence of the chaotropic salt, NaSCN. Establishment of quantitation methods for both cytosolic and nuclear forms of EBA will enable future investigation of the mechanism and regulation of estrogen action in the liver of this turtle species.

Animals↗
PubMed1987

Identification of an estrogen receptor in the testis of the sea lamprey, Petromyzon marinus.

Employing a hydroxylapatite batch assay, estrogen-binding activities (EBAs) were demonstrated in the cytosol and nuclear extract of the testis of the anadromous sea lamprey, Petromyzon marinus. The lamprey testicular EBAs are sensitive to trypsin digestion and bind [3H]estradiol-17 beta with high affinities (cytosolic Kd = 0.52 nM; nuclear Kd = 0.39 nM) and limited capacities (cytosolic: 56.2 fmol/g tissue; nuclear: 68.2 fmol/g tissue). Androgens, progesterone, and corticosterone displayed little affinities for lamprey EBAs. Thus, lamprey testicular EBA possessed many definitive properties of an estrogen receptor as described in amphibian, reptilian, and mammalian studies. No specific binding to androgens was detected in either testicular subcellular fraction. The presence of a putative estrogen receptor in lamprey testis suggests a functional role of estrogen in testicular regulation in this ancient vertebrate.

Animals↗
PubMedDate not supplied

Market concentration in secondary health services under a purchaser-provider split: the New Zealand experience.

The separation of purchaser and provider in government-funded health systems enables competition to develop between providers. Competition is seen as a means to drive technical efficiencies by providers. While it is difficult to assess comprehensively the level of competition in a market taking into account contestability and substitutability effects, it is possible to measure the degree of market concentration. This paper employs the Hirschman-Herfindahl index to provide measures of market concentration in selected secondary health care markets in New Zealand immediately prior to (1992) and following (1994) implementation of a purchaser-provider split. The results show that, generally, the selected markets are highly concentrated and that there has been little change in the degree of concentration over the 2 year period under investigation. The paper also discusses some of the methodological problems associated with the measurement of market concentration and acknowledges the limitations of such measures as indicators of competition.

Catchment Area, Health↗
PubMedDate not supplied

Dyspnea in patients with chronic obstructive pulmonary disease: does dyspnea worsen longitudinally in the presence of declining lung function?

OBJECTIVE: To determine the direction and rate of change in the symptom of dyspnea in patients with chronic obstructive pulmonary disease (COPD) whose lung function has worsened over time. DESIGN: Secondary analysis of a longitudinal data set. SETTING: Outpatient clinic. PATIENTS: Thirty-four medically stable male subjects with chronic obstructive pulmonary disease studied for 5.3 +/- 3.5 years, with a mean reduction in FEV1 over the period studied of 330.9 +/- 288.0 mL. Subjects were 63.3 +/- 5.5 years of age at entry into the study. OUTCOME MEASURES: Dyspnea and functional status scores were obtained using the Pulmonary Functional Status and Dyspnea Questionnaire. RESULTS: There was no significant difference in reports of dyspnea from the beginning to the end of the study, despite significant reductions in lung function. Of all activities studied, dyspnea when raising arms overhead was the only activity showing a relationship to the slope of change in FEV1 %. CONCLUSION: These findings suggest that, although patients with chronic lung disease experience varying degrees of deterioration in lung function longitudinally, there is no evidence that they report worsening of dyspnea in tandem with these physiologic changes. In this study, patient ratings of dyspnea longitudinally were not directly linked to changes in lung impairment.

Disease Progression↗
PubMedDate not supplied

[Cognitive and behavioral disorders in Parkinson disease].

INTRODUCTION: Most patients with Parkinson's disease have cognitive and behavior disorders during the course of their illness. OBJECTIVE: In this study we consider practical aspects of the treatment of patients with Parkinson's disease who have such problems. DEVELOPMENT: Better understanding of both normal and abnormal physiology of the basal ganglia and their connections makes it possible to suggest hypotheses regarding the cause of these disorders. The combination of lesions of multiple subcorticocortical systems with different degrees of direct cortical pathology due to Lewy bodies and neuritic plaques may explain most of the changes, from depression to dementia. CONCLUSIONS: It is necessary to test these concepts using studies based on specific predictions derived from pathophysiological models. Until this is done, the clinical treatment of cognitive and compartmental disorders in Parkinson's disease will continue to be symptomatic, complex and controversial.

Brain↗