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Biomedical subjects

M Goldstein

Publications and source records attributed to M Goldstein.

At least 271 records · Page 15Linked to original sources
PubMed1990

Psychosocial factors as predictors of length of stay of Medicare patients under the prospective payment system.

The Prospective Payment System methodology is designed to predict inpatient hospital resource utilization. The system sets standards based on medical diagnosis (Diagnosis Related Groups), but it ignores psychosocial characteristics which often determine discharge options and therefore, directly affect a patient's length of stay. A study is described which examined the psychosocial characteristics of 234 elderly hospitalized patients in relation to length of stay and route of admission (elective or emergency room). Such data can be very useful to discharge planners in identifying high social risk patients, as well as to health planners attempting to modify the DRG methodology to incorporate psychosocial factors.

Age Factors↗
PubMed1990

The Decade of the Brain: an era of promise for neurosurgery and a call to action.

On July 25, 1989, President Bush signed a bill declaring the 1990's to be the Decade of the Brain. This offers the clinical and basic neuroscience communities an opportunity to join with the National Institute of Neurological Disorders and Stroke in moving ahead vigorously with research aimed at preventing and treating neurological disease. Neurosurgery must be an active participant in this national endeavor; its influence, skills, and contributions are needed.

Brain↗
PubMed1990

Receptor reserve for 5-hydroxytryptamine1A-mediated inhibition of serotonin synthesis: possible relationship to anxiolytic properties of 5-hydroxytryptamine1A agonists.

The irreversible receptor antagonist N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) was used to determine the relationship between receptor occupancy and response at central 5-hydroxytryptamine1A (5-HT1A) serotonin receptors mediating the inhibition of serotonin synthesis in rat cortex and hippocampus. Rats were treated with vehicle or EEDQ (2 or 6 mg/kg) and 24 hr later dose-response curves were constructed for inhibition of 5-hydroxytrytophan (5-HTP) accumulation (after decarboxylase inhibition with NSD-1015) by the selective 5-HT1A agonists 8-hydroxy-2(di-n-propylamino)tetralin (8-OH-DPAT) (0.01-3 mg/kg), buspirone (0.1-7.5 mg/kg), and ipsapirone (0.1-6.25 mg/kg) and the 5-HT1A agonist/antagonist BMY 7378 (0.015-5 mg/kg). In vehicle-pretreated rats, a similar maximal inhibition of 5-HT synthesis (range, 52-59%) was observed in both brain areas with 8-OH-DPAT, buspirone, and ipsapirone. These three agonists were also more potent in reducing 5-HTP accumulation in the cortex than in the hippocampus (ED50, 8-OH-DPAT, 14 and 30 microgram/kg; buspirone, 0.42 and 0.63 mg/kg; ipsapirone, 0.44 and 1.26 mg/kg, respectively). In the cortex, EEDQ treatment shifted the dose-response curves for 8-OH-DPAT, buspirone, and ipsapirone 8.6-, 2.0-, and 2.8-fold to the right, respectively. Corresponding rightward shifts in the hippocampus were smaller, 6.0-, 1.6-, and 2.1-fold, respectively. The EEDQ-induced shifts in the dose-response curves were accompanied by reductions in maximal response. In contrast, whereas the maximal inhibition of cortical 5-HTP accumulation by BMY 7378 (55%) was similar to that obtained with the agonists, maximal response in the hippocampus was much smaller (32%). Furthermore, in both brain regions EEDQ reduced the maximal response to BMY 7378 without shifting the dose-response curves. Analysis of the data by the double-reciprocal method of Furchgott, followed by calculation of fractional receptor occupancy for each dose of agonist, revealed a nonlinear relationship between receptor occupancy and response for 8-OH-DPAT, buspirone, and ipsapirone in both brain regions, demonstrating the presence of a large receptor reserve. For BMY 7378, in contrast, linear relationships were obtained. Because 5-HT1A receptor-mediated regulation of 5-HT synthesis appears to be mediated by somatodendritic autoreceptors on 5-HT neurons in the midbrain raphé nuclei, the results suggest that these autoreceptors possess a large receptor reserve for agonists. The relevance of these findings for the mechanism of action of nonbenzodiazepine anxiolytics is discussed.

5-Hydroxytryptophan↗
PubMed1990

Dopamine agonist-induced elevation of striatal acetylcholine: relationship between receptor occupancy and response in normal and denervated rat striatum.

Unilateral denervation of the nigrostriatal dopamine (DA) pathway with 6-hydroxydopamine resulted in a supersensitive response for elevation of striatal acetylcholine concentrations by the full DA agonist (R)-(-)-N-n-propylnorapomorphine (NPA), reflected in a parallel 4-fold leftward shift in the dose-response curve (ED50, intact, 8.8 micrograms/kg; denervated, 2.2 micrograms/kg). The maximal response, however, was not changed. In the intact striatum, irreversible DA receptor inactivation with N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) (6 mg/kg) produced a depression in the maximal acetylcholine increase elicited by NPA (control, 52.4%; EEDQ, 25.0%), without altering the ED50 for the agonist. In contrast, in the denervated striatum, EEDQ treatment produced a much smaller reduction in the maximal response (to 39.6%), as well as a small rightward shift in the ED50 (from 2.2 to 3.5 micrograms/kg). Double-reciprocal analysis of equieffective doses of NPA necessary to elicit response yielded similar values for the pseudo-dissociation constant (pseudo-KA, in units of dose) in intact and denervated striatum (8.3 and 7.0 micrograms/kg, respectively). A plot of receptor occupancy versus response was linear for the intact striatum, indicating the absence of a receptor reserve. In contrast, a nonlinear relationship was obtained for the denervated side, and a small apparent receptor reserve for NPA of 25-30% was estimated to be present. The results suggest that 6-hydroxydopamine-induced supersensitivity reflects the generation of a postsynaptic D2 DA receptor reserve, which may account for the observation that weak partial agonist elicit measurable response in supersensitive animals (and at presynaptic DA receptors, which normally exhibit a receptor reserve for agonists) but not at normosensitive receptors devoid of spare receptors.

Acetylcholine↗
PubMed1989

Acute treatment with clozapine blocks D1 dopamine receptor binding in discrete brain areas of the male rat.

The ability of acute treatment with clozapine in vivo to block D1 receptors in the rat telencephalon and midbrain was investigated using the irreversible inactivation of [125I]SCH 23982 binding sites by N-ethoxy-carbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ; 6 mg/kg, i.p., 24 h). As analyzed by quantitative autoradiography, clozapine (40 mg/kg, i.p., 15 min before EEDQ administration) was found to produce a partial protection of central D1 receptors in all brain areas investigated, including cerebrocortical regions. These data could perhaps explain the failure of clozapine to induce tardive dyskinesia upon chronic treatment.

Animals↗
PubMed1989

Somatostatin-like immunoreactivity in rat main olfactory bulb: extent of coexistence with neuropeptide Y-, tyrosine hydroxylase- and vitamin D-dependent calcium binding protein-like immunoreactivities.

A double-labeling immunofluorescence colocalization technique was used to examine the extent of coexistence of somatostatin (SOM)-like immunoreactivity with neuropeptide Y (NPY)-, tyrosine hydroxylase (TH)- and vitamin D-dependent calcium binding protein (D-CaBP)-like immunoreactivities in neurons of the rat main olfactory bulb. SOM-like immunoreactivity (SOM-I) was distributed within restricted populations of periglomerular neurons and deep short-axon cells, and rarely within superficial short-axon cells at the glomerular layer/external plexiform layer (GL/EPL) border region. Double-labeling analysis revealed that all of the SOM-I deep and superficial short-axon cells also contained NPY-I. Colocalization of SOM-I and TH-I or of SOM-I and D-CaBP-I was infrequently observed within periglomerular neurons. The rare SOM-I short-axon cells at the GL/EPL border always exhibited D-CaBP-I. These results demonstrate virtual complete coexistence of SOM and NPY in short-axon neurons of the main olfactory bulb. With a few exceptions, however, bulbar SOM neurons appear to constitute subclasses of periglomerular cells immunohistochemically distinct from those containing TH or D-CaBP.

Animals↗
PubMed1989

Evidence for the existence of a population of arcuate neurons costoring choline acetyltransferase and tyrosine hydroxylase immunoreactivities in the male rat.

By combined immunoperoxidase and immunofluorescence histochemistry we have analyzed the distribution of choline acetyltransferase (ChAT) and tyrosine hydroxylase (TH) immunoreactive (IR) perikarya within the same sections of the mediobasal hypothalamus of the male rat. Evidence was obtained for the existence of perikarya costoring TH and ChAT immunoreactivities in both the dorsomedial and ventrolateral part of the arcuate nucleus and in the adjacent periarcuate nucleus at all rostrocaudal levels. The results strongly implicate interactions between dopamine and acetylcholine as well as acetylcholine and growth hormone releasing factor in dorsomedially and ventrolaterally located TH/ChAT costoring tuberoinfundibular neurons, respectively.

Animals↗
PubMed1989

Bundle branch block during orthodromic reciprocating tachycardia onset in infants.

Transesophageal electrophysiologic studies were performed in 58 infants (age less than or equal to 1 year, median 10 days) with electrocardiographically documented orthodromic reciprocating tachycardia (ORT). The aim was to evaluate the occurrence, type and electrophysiologic effects of bundle branch block (BBB) during ORT onset. Of the 58 infants, 25 (43%) had BBB with pacing-induced tachycardia onset. BBB was initiated by single or double premature atrial extrastimuli and by burst atrial pacing; 4 infants also demonstrated BBB with spontaneous ORT onset during transesophageal study. Two of 25 infants had BBB only after intravenous procainamide. Comparison of the 25 infants exhibiting BBB at ORT onset with the 33 infants not demonstrating BBB revealed that age was not statistically different in the 2 groups, but that severity of illness (based on a 1 to 3 scale) was greater (p less than 0.05) and normal QRS ORT cycle length was shorter (p less than 0.02) in the infants with BBB. Of the 25 infants with BBB at ORT onset, 17 had left BBB, 3 had right BBB and 5 had both left and right BBB. Ventriculoatrial interval or cycle length increases during ORT with BBB in 16 of 25 (64%) infants suggested left free wall-accessory atrioventricular connections.(ABSTRACT TRUNCATED AT 250 WORDS)

Bundle-Branch Block↗
PubMed1989

A new group of tyrosine hydroxylase-immunoreactive neurons in the cat thalamus.

A new cell group composed of a large number of neurons immunoreactive to tyrosine hydroxylase (TH) was demonstrated in the paraventricular nucleus and midline nuclei of the cat thalamus, using four different anti-TH sera after colchicine treatment. However, in these regions, we did not detect any cell bodies containing other catecholamine synthesizing enzymes nor dopamine.

Animals↗
PubMed1989

A direct effect of 24,25-(OH)2D3 and 1,25-(OH)2D3 on the modeling of fetal mice long bones in vitro.

To examine the effects of 24,25-(OH)2D3 and 1,25-(OH)2D3 on fetal long bone modeling the radii and ulnae of 16 day fetal mice were grown in vitro for 2 days. Their growth, mineralization, and resorption were assessed by measuring diaphyseal length, calcium and phosphorus content, hydroxyproline-protein ratios, and the release of incorporated 45Ca. The results showed that 24,25-(OH)2D3 at concentrations of 10(-10)-10(-8) M stimulated the growth of the bones as indicated by their increased diaphyseal length, periosteal bone area, and hydroxyproline content. Calcium and phosphorus content was significantly increased; 45Ca release was unaltered. Bones incubated in media containing 10(-6) M 24,25-(OH)2D3 responded in a similar fashion to bones incubated in media containing 10(-10)-10(-8) M 1,25-(OH)2D3, with inhibition of bone growth as indicated by reduced diaphyseal length, periosteal bone area, hydroxyproline-protein ratios, and calcium and phosphorus content; 45Ca release was significantly increased. Neither metabolite affected total bone length. The results suggest a role for 24,25-(OH)2D3 in the growth of fetal mice bones in vitro and also confirm the findings from previous studies that 1,25-(OH)2D3 and high concentrations of 24,25-(OH)2D2 stimulate bone resorption.

24,25-Dihydroxyvitamin D 3↗
PubMed1989

Galanin-, neuropeptide Y- and enkephalin-like immunoreactivities in catecholamine-storing paraganglia of the fetal guinea pig and newborn pig.

The occurrence and distribution of several neuropeptides and transmitter enzymes have been investigated by means of indirect immunofluorescence histochemistry in preaortal and carotid body-like paraganglia of the fetal guinea pig and the newborn pig. Preaortal paraganglia from the celiac and inferior mesenteric ganglion regions in fetal guinea pigs showed cell bodies immunoreactive (IR) for tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), neuropeptide Y (NPY), galanin (GAL) and metenkephalin (ENK). Almost all cells were IR for TH and DBH, whereas NPY-like immunoreactivity (-LI), GAL-LI and ENK-LI occurred less frequently. Direct double-labeling revealed the coexistence of NPY/GAL, NPY/ENK and GAL/ENK in paraganglion cells from the celiac and inferior mesenteric region. Nerve fibers and terminals were IR for ENK; fibers IR for calcitonin-gene-related peptide (CGRP) were present in the inferior mesenteric ganglion region. Preaortal paraganglia cells from the newborn pig showed TH-LI, DBH-LI, GAL-LI and ENK-LI, the distribution pattern being similar to that seen in the guinea pig; however, NPY-LI was absent. Carotid-body-like paraganglia from the newborn pig showed cell bodies IR to TH, GAL and ENK. Few cells were seen with DBH-LI. A rich supply of nerve fibers with CGRP-LI was present; some fibers exhibited ENK-LI and CCK-LI. In the adjacent superior cervical ganglion, ganglion cell bodies showed immunoreactivity to TH, DBH and NPY. A small number of cells were positive for GAL, CGRP and vasoactive intestinal polypeptide (VIP). Physiological activation of the paraganglia, leading to release or increase in catecholamines, may also change the content of the neuropeptides present in the paraganglia.

Animals↗