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Biomedical subjects

G Snyder

Publications and source records attributed to G Snyder.

At least 19 recordsLinked to original sources
PubMed2000

Dating of pore waters with (129)I: relevance for the origin of marine gas hydrates

Pore waters associated with gas hydrates at Blake Ridge in the Atlantic Ocean were dated by measuring their iodine-129/iodine ratios. Samples collected from sediments with ages between 1.8 and 6 million years ago consistently yield ages around 55 million years ago. These ages, together with the strong iodine enrichment observed in the pore waters, suggest that the origin of iodine is related to organic material of early Tertiary age, which probably is also the source of the methane in the gas hydrates at this location.

Journal Article↗
PubMed2000

Inducement of fluent speech in persons who stutter via visual choral speech.

A novel phenomenon of fluency enhancement via visual gestures of speech in the absence of traditional auditory feedback is reported herein. The effect on visual choral speech on stuttering frequency was investigated. Ten participants who stuttered recited memorized text aloud under two conditions. In a visual choral speech (VCS) condition participants were instructed to focus their gaze on the face, lips and jaw of a research assistant who 'silently mouthed' the text in unison. In a control condition, participants recited memorized text to the research assistant who sat motionless. A statistically significant (P=0.0025) reduction of approximately 80% in stuttering frequency was observed in the VCS condition. As visual linguistic cues are sufficient to activate the auditory cortex, one may speculate that VCS induces fluency in a similar yet undetermined manner as altered auditory feedback does.

Adult↗
PubMed1998

Effects of aerosolized synthetic surfactant, atovaquone, and the combination of these on murine Pneumocystis carinii pneumonia.

An immunosuppressed rat model was used to determine the pharmacokinetics of aerosolized atovaquone (administered with and without a synthetic surfactant) and to evaluate the efficacy of inhaled atovaquone in the prevention and treatment of Pneumocystis carinii pneumonia (PCP). After a single dose by aerosol, mean peak concentrations of atovaquone averaged 52 microg/mL in plasma and 31 microg/g in lungs of rats infected with P. carinii. When atovaquone was combined with surfactant, mean peak concentrations of 94 microg/mL in plasma and 51 microg/g in lung were achieved. Aerosolized synthetic surfactant alone significantly increased survival of rats with PCP and, when combined with atovaquone, increased plasma and lung concentrations of the drug and eradication of the organism.

Administration, Inhalation↗
PubMed1997

The anatomy of an OPTI: Part 2. The CORE system. Ohio Osteopathic Hospital Association. Ohio Association of Osteopathic Medical Directors. Ohio Osteopathic Association.

In July 1995, the American Osteopathic Association (AOA) Board of Trustees passed new regulations regarding the accreditation of osteopathic graduate medical education (GME) by establishing the Osteopathic Postdoctoral Training Institutions (OPTI) system. This system must be phased in by July 1999. The principal changes resulting from the OPTI system include establishing requirements for college cosponsorship of GME programs and for the number of residency programs, interns, and residents to be trained by the OPTI. In essence, OPTI is an osteopathic acronym for consortium. Each OPTI must include at least one college of osteopathic medicine (COM) and one AOA-accredited hospital. The OPTIs will be subject to interval AOA inspections and will be required to demonstrate a governing system, mission statement, organizational structure, and the presence of faculty development programs. The first article in this two-part series, published in the October JAOA, provided a general blueprint for OPTI building and presented both positive and negative issues germane to the formation of OPTIs. Part 2 reinforces the considerations outlined in Part 1 by describing the formation of a large OPTI--the Ohio University College of Osteopathic Medicine (OU-COM) Centers of Osteopathic Regional Education (CORE) system. Key features are described, including the mission statement, organizational structure, committee system, governance, GME programs, operations, and budget.

Accreditation↗
PubMed1996

Medicaid primary care services in New York State: partial capitation vs full capitation.

BACKGROUND: Forty-nine states have applied to the Health Care Financing Administration for waivers to allow special program development for Medicaid recipients. In an effort to identify issues relevant to making the transition of its entire Medicaid population into a capitation model, New York State has encouraged the development of partial capitation and full capitation models. This paper is a critical description analysis of a 1-year experience, utilizing data provided by the New York State Department of Social Services. METHODS: Data collected by the New York State Department of Social Services were used to compare the costs for matched cohorts enrolled in partial capitation programs in which the primary care physician is paid a monthly fee to provide ambulatory primary care for Medicaid recipients; and full capitation programs in which a health maintenance organization (HMO) or a hospital-based prepaid health services program (PHSP) is paid a more encompassing monthly fee to provide a larger range of services, including inpatient, outpatient, and specialty care. RESULTS: Partial capitation programs were reported to save the state 38% compared with a matched control group enrolled in traditional, fee-for-service Medicaid (P<.05), and offered greater savings than HMOs and PHSPs (P=NS). The HMOs and PHSPs saved the state 9.3% and 16.8%, respectively, compared with traditional enrollment. Quality measures and patient satisfaction for partial and full capitation programs were equivalent. CONCLUSIONS: These data suggest that New York State primary care physicians who participated in programs that reimburse a prepaid monthly fee for outpatient primary care services achieved savings comparable to those of HMOs. A partial capitation primary care model may offer an affordable and more flexible alternative to full-service HMOs in caring for Medicaid recipients, especially in communities with limited HMO penetration.

Capitation Fee↗
PubMed1994

Impact of increasing calcium in the diet on nutrient consumption, plasma lipids, and lipoproteins in humans.

This study examined the feasibility of increasing food-derived calcium to 1500 mg/d and the impact of this change on plasma lipids and nutrient consumption in hypertensive (n = 130) and normotensive (n = 196) participants. Three interventions were applied in a randomized, parallel, placebo-controlled fashion: 1) counseling to increase dietary calcium through food consumption to 1500 mg/d (n = 106), 2) a 1000-mg/d calcium supplement (n = 109), or 3) placebo (n = 111). Plasma lipids were measured before and after 12 wk of intervention whereas nutrient intake was monitored throughout the study. At baseline, hypertensive patients reported lower intakes of carbohydrates, calcium, magnesium, phosphorus, potassium, iron, vitamin D, thiamin, and riboflavin (all P < 0.05). They also had lower HDL (P = 0.014) and higher LDL (P < 0.05) compared with normotensive subjects. During intervention, calcium, magnesium, phosphorus, potassium, thiamin, riboflavin, and vitamins C and D increased (P < 0.01) in the group receiving food calcium but not in the placebo or supplement groups. No changes occurred in plasma lipids or lipoproteins after 12 wk of intervention.

Adolescent↗
PubMed1994

Aerosol characteristics of 99mTc-pentetic acid (DTPA) and synthetic surfactant (Exosurf).

This study evaluated the feasibility of using 99mTc-pentetic acid (DTPA) as a radioactive tracer for aerosolized synthetic surfactant (DPPC, cetyl alcohol, tyloxapol). The 99mTc-DTPA was admixed with surfactant and aerosolized using a nebulizer system interfaced to a ventilator with a cascade impactor attached to the endotracheal tube. Particle size distribution for DPPC, cetyl alcohol, and 99mTc-DTPA were almost identical during the 0- to 15-, 15- to 30-, and 0- to 30-min collection periods. Tyloxapol exhibited a unique distribution pattern with increased deposition in large (> 10 microns) and small (0.65 to 1.1 microns) particles. The mass median aerodynamic diameter for all aerosolized components was in the respirable range of 2.1 to 2.5 microns. A mixture of 99mTc-DTPA with synthetic surfactant appears to be a reasonable method to evaluate surfactant deposition.

Aerosols↗
PubMed1993

Distribution of dopamine- and cAMP-dependent phosphoprotein (DARPP-32) in the developing and mature kidney.

DARPP-32 is a dopamine- and cAMP-regulated inhibitor of protein phosphatase-1 (PP-1). Dopamine and DARPP-32 regulate sodium reabsorption in renal tubules by inhibiting the activity of Na+,K(+)-ATPase. We here report the pre- and postnatal distributions of DARPP-32 in the kidney as demonstrated by immunoblotting and immunohistochemistry. With immunoblotting we examined the abundance of DARPP-32 and the functionally similar but more widespread inhibitor of PP-1, inhibitor-1 (I-1). We compared their relative abundance in the renal cortex, renal medulla and neostriatum from the brain, where DARPP-32 is greatly enriched. DARPP-32 levels in the adult rat were fourfold higher in the neostriatum than in the renal medulla and 13-fold higher than in the renal cortex. I-1 levels were approximately the same in the neostriatum and in the renal medulla and 2.5-fold higher in neostriatum than in the renal cortex. Between postnatal day 10 (PN10) and 40 (PN40) DARPP-32 abundance increased 1.3-fold in the neostriatum, 1.4-fold in the renal cortex and sixfold in the medulla. The abundance of I-1 did not increase in the striatum from PN10 to PN40 but increased 1.5-fold in the renal cortex and threefold in the renal medulla. Thus, during the time of maturation of tubular transport function, the levels of both PP-1 inhibitors increased in the kidney, the largest increase being found in the renal medulla. With immunohistochemistry strong DARPP-32-like-immunoreactivity (DARPP-32-LI) was detected in the ureteral buds from gestational day 18 and up to postnatal day 8 when nephrogenesis was completed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

High-frequency oscillatory ventilation and extracorporeal membrane oxygenation for the treatment of acute neonatal respiratory failure.

Forty-six (92%) outborn and four (8%) inborn term or near-term neonates were admitted for extracorporeal membrane oxygenation (ECMO) treatment to a neonatal intensive care unit between July 1, 1985, and November 1, 1987. All infants had PAO2-PaO2 greater than or equal to 600 mm Hg in spite of aggressive conventional ventilatory and pharmacologic therapy. All patients were offered rescue treatment with high-frequency oscillatory ventilation (HFOV), and only if there was no improvement in PAO2-PaO2 with HFOV were infants treated using ECMO. Four patients died before receiving an adequate trial of HFOV and before emergency ECMO support could be initiated; 21 patients, all of whom survived to hospital discharge, responded to HFOV; 25 patients ultimately required ECMO therapy for cardiopulmonary support, with 22 (88%) surviving to discharge. Neonates responding to HFOV were of slightly younger gestational age (38 +/- 2 weeks vs 40 +/- 2 weeks, mean +/- SD; P less than .001) and more frequently had clinical evidence of pneumonia (11 of 21 vs 2 of 25; P less than .002). There was no statistically significant difference in outcome with respect to the number of ventilator days, hospital days, or survival between patients responding to HFOV and patients who required ECMO. Morbidity was increased in ECMO patients, with bleeding abnormalities, seizures, and renal failure occurring more frequently than in HFOV-treated infants. Overall, 92% (46 of 50) of the patients were treated with a staged protocol using HFOV before ECMO. A total of 46% (21 of 46) responded to HFOV treatment alone and did not require ECMO therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Extracorporeal Membrane Oxygenation↗
PubMed1989

Nitric oxide and nitrous oxide production and cycling during dissimilatory nitrite reduction by Pseudomonas perfectomarina.

The denitrifier Pseudomonas perfectomarina reduced nitrite under conditions of kinetic competition between cells and gas sparging for extracellular dissolved nitric and nitrous oxides, NOaq and N2Oaq, in a chemically defined marine medium. Time courses of nitrite reduction and NOg and N2Og alpha removal were integrated to give NOg and N2Og yields. At high sparging rates, the NOg yield was greater than 50% of nitrite-N reduced, and the yield of NOg + N2Og was approximately 75%. Hence interrupted denitrification yields NOaq and N2Oaq as major products. The yields varied with sparging rates in agreement with a quantitative model of denitrification (Betlach, M. P., and Tiedje, J.M. (1981) Appl. Environ. Microbiol. 42, 1074-1084) that applies simplified Michaelis-Menten kinetics to NO2-----NOaq----N2Oaq----N2. The fit gave an estimate of the maximum scavengeable NOaq yield of 73 +/- 8% of nitrite-N. Thus a minor path independent of NOaq is also required. The fit of the model to data at lower sparging rates, where normal denitrification products predominate, implies that the extracellular NOaq pool yield is independent of gas sparging rate. Thus in P. perfectomarina NOaq and N2Oaq are intermediates, or facilely equilibrate with true intermediates, during complete denitrification. The recovery of most nitrite-N as NO and/or N2O under perturbed conditions is not an artifact of irreversible product removal, but an attribute of denitrification in this species, and most probably it is characteristic of denitrification in other species as well.

Kinetics↗
PubMed1988

Hypothalamic action of delta-9-tetrahydrocannabinol to inhibit the release of prolactin and growth hormone in the rat.

The site of action of delta-9-tetrahydrocannabinol (THC) to inhibit the release of prolactin (PRL) and growth hormone (GH) was examined by in vivo and in vitro experiments. In conscious freely moving animals bearing implanted third ventricular (3V) and external jugular cannulae, THC or the diluent was microinjected into the 3V and blood samples were removed to determine the effect on plasma PRL and GH. Both the 0.4- and 4-micrograms dose injected intraventricularly resulted in a suppression of PRL and GH release as indicated by declines in plasma levels within 40-80 min which were highly significant statistically but not dose-related. The higher dose evoked a pulse of GH and/or PRL in most animals which preceded the lowering of hormonal levels. In the in vitro experiments dipersed anterior pituitary cells were incubated with 5 x 10(-8) or 5 x 10(-9)M THC or the diluent for 5 days. Fresh culture medium was added to the cells after 3 days and the cells cultured for an additional 2 days. After this period, the cells were incubated for an additional 2 h in culture medium with or without THC plus a near maximal dose of thyrotropin-releasing hormone and GH-releasing factor (50 and 10 ng/ml, respectively) or the diluent to evaluate the response of PRL and GH release, respectively. Neither dose of THC altered the release or storage of the two hormones during culture or affected the response to the releasing hormones which is suggestive that there is no direct effect of THC on either GH or PRL release.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

An experience with epidural morphine in lumbar surgery patients.

A chart review of the patients who received epidural morphine for lumbar surgery during the first year of implementation of the procedure was conducted. This article reviews the pharmacology and side effects of epidural morphine, describes the procedure of administering epidural morphine, discusses side effects and technical problems encountered, and presents implications for nursing practice.

Catheters, Indwelling↗
PubMed1987

Management of the fetus with urinary tract dilatation.

This report describes our experience with 18 pregnant women who presented to our center with suspected fetal urinary tract dilatation. The patients were divided into 4 groups: group I had unilateral fetal urinary tract dilatation and normal amniotic fluid volume, group II had bilateral dilatation and normal amniotic fluid volume, group III had bilateral dilatation and oligohydramnios, group IV had nonurinary tract malformations in addition to urinary tract dilatation. Patients with normal amniotic fluid volume and either unilateral or bilateral fetal dilatation (groups I and II) had a good pregnancy outcome. Patients with oligohydramnios and bilateral dilatation had a poor pregnancy outcome. No intrauterine surgery or shunting was performed in any of the patients. The initial diagnosis of urinary tract dilatation led to the prenatal diagnosis of major nonurologic malformations (group IV) in 3 patients who also had a poor outcome. An algorithm is presented that reflects our experience with the management of these patients and could serve as a guide for others caring for similar patients.

Amniotic Fluid↗
PubMed1986

5,6-Epoxyeicosatrienoic acid mobilizes Ca2+ in anterior pituitary cells.

Luteinizing hormone releasing hormone stimulates the concomitant release of luteinizing hormone and 45Ca2+ from prelabeled anterior pituitary cells. Indomethacin (10 microM) and nordihydroguaiaretic acid (10 microM) had no effect on the luteinizing hormone releasing hormone-stimulated release of either luteinizing hormone or 45Ca2+. Eicosatetraynoic acid (10 microM) blocked both luteinizing hormone releasing hormone-stimulated luteinizing hormone secretion and luteinizing hormone releasing hormone-stimulated 45Ca2+ efflux. 5,6-Epoxyeicosatrienoic acid stimulated both luteinizing hormone secretion and 45Ca2+ efflux from anterior pituitary cells. Additionally, 5,6-epoxyeicosatrienoic acid closely mimics the ability of luteinizing hormone releasing hormone to increase intracellular free calcium. These results are consistent with the hypothesis that 5,6-EET alters calcium homeostasis in a manner similar to that observed during luteinizing hormone releasing hormone stimulation of luteinizing hormone release.

8,11,14-Eicosatrienoic Acid↗