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Biomedical subjects

G Landsberg

Publications and source records attributed to G Landsberg.

At least 19 recordsLinked to original sources
PubMed1989

Future directions.

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Financing, Government↗
PubMed1987

Sodium balance as a determinant of prostacyclin production by isolated rat aorta.

The present study investigates whether the synthesis of prostacyclin (PGI2) in isolated rat aorta is dependent on the state of sodium balance of the animals. Three groups of ten rats each were included into the study. Two of them were fed a diet low in NaCl for 10 days with group I receiving 0.9% saline and group II distilled water as drinking fluid. Group III received a regular rat chow containing approximately 0.8 mmol day-1 of sodium, also for 10 days. At the end of the dietary protocol, systolic arterial blood pressure was significantly higher in group I (109.9 +/- 2.4 mmHg) as compared to group II (101.0 +/- 2.4 mm Hg; P less than 0.05) and group III animals (102.2 +/- 1.6 mm Hg; P less than 0.05). Generation of PGI2-like activity was determined in portions of the animals' isolated aorta using a platelet aggregation bioassay following incubation in 0.05 M Tris buffer (pH 9.3) for 12, 15, and 30 min, respectively. During these incubation times, generation of PGI2-like activity averaged 48.6 +/- 3.5, 57.8 +/- 4.3 and 68.3 +/- 3.2 pmol mg-1 in group III animals, which had received the regular rat chow, with similar values in the low salt group II (50.2 +/- 2.5, 57.7 +/- 2.7 and 72.9 +/- 3.7 pmol mg-1). Aortic generation of PGI2-like material was significantly suppressed in the high salt group I (37.5 +/- 2.8, 46.2 +/- 3.2 and 61.3 +/- 4.0 pmol mg-1; P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1986

Converting enzyme inhibitor ramipril stimulates prostacyclin synthesis by isolated rat aorta: evidence for a kinin-dependent mechanism.

The present study was performed to investigate the effect of the angiotensin I-converting enzyme inhibitor ramipril on vascular synthesis of prostacyclin (PGI2). Administration of ramipril (Hoe 498) to rats significantly stimulated prostacyclin (PGI2) synthesis, quantified by radioimmunoassay of its stable hydrolysis product 6-keto-PGF1 alpha, by portions of the animals' isolated aorta. This effect was maximal at a dose range of 10(-7) mol/kg ramipril. The addition of the active ramipril metabolite ramipril diacid directly into the incubation buffer at final concentrations of 10(-9), 10(-6), and 10(-4) M resulted in a dose-dependent stimulation of 6-keto-PGF1 alpha released by isolated aortic tissue. Pretreatment of rats with aprotinin (40,000 U s.c. 60 min before the incubations) attenuated the ramipril-induced effect on aortic 6-keto-PGF1 alpha synthesis. Our results show that the angiotensin I-converting enzyme inhibitor ramipril stimulates PGI2 synthesis in vascular tissue and that this effect may be secondary to changes in the activity of the kinin system.

6-Ketoprostaglandin F1 alpha↗
PubMed1985

Quality assurance activities in community mental health centers: changes over time.

How have Quality Assurance (QA) Programs fared over time in community mental health centers (pre and postlegislative mandates) and what has their impact on CMHC's been? These are the essential questions which are the subject of this paper that discusses surveys of QA activities in CMHC's conducted in 1977 by the Council on Research and Evaluation of NCCMHC and in 1983 by the author. The data from the survey revealed that despite the removal of mandates, the last years have been very productive for QA systems. QA growth in most areas of CMHC services has occurred, systems have grown more sophisticated and extensive and appear to be having a significant impact on centers. The paper suggests that the future QA systems looks promising but that further research is necessary.

Community Mental Health Centers↗
PubMed1984

Further studies on the mechanism of increased blood pressure during dietary linoleic acid deprivation.

The present studies investigate the changes in blood pressure and excretory renal function in rats during dietary linoleic acid deprivation. Four groups of animals were fed isocaloric diets containing 10 en % saturated fat and either 5 en % linoleic acid (groups I and III) or 5 en % oleic acid (groups II and IV). In addition, groups I and II received a chronic high intake of Na (greater than 5 mmol/day) while groups III and IV were Na restricted with an average Na intake of 0.7 mumol/day. Blood pressure significantly increased in the high salt, linoleic acid deprived group II and was unchanged in all three other groups of animals. De novo synthesis of prostaglandin E2 in rat kidney inner medullary homogenates in the four groups of animals at the end of the dietary protocol showed a marked dependency on Na balance with significantly (p less than 0.01) higher values in the Na restricted animals as well as on linoleic acid intake with significantly (p less than 0.01) higher values in the linoleic acid substituted animals. Urinary excretion of NaCl during acute expansion of the extracellular fluid volume with hypotonic saline was significantly impaired in the animals receiving oleic acid instead of linoleic acid. In a metabolic study, linoleic acid deprived animals retained Na from the first day of linoleic acid deprivation and blood pressure started to rise only after a substantial amount of Na had been retained. Our results show that linoleic acid deprivation suppresses renal arachidonic acid cyclooxygenase metabolism and impairs the renal ability to excrete an acute salt load. Impaired renal excretory function precedes the increase in blood pressure. Thus suppressed renal cyclo-oxygenase metabolism which impairs renal excretory function may be a crucial mechanism in the rise of blood pressure during dietary linoleic acid deprivation.

Animals↗
PubMed1983

The converting enzyme inhibitor captopril stimulates prostacyclin synthesis by isolated rat aorta.

In the present study, pretreatment of rats with captopril significantly stimulated prostacyclin (PGI2) synthesis by their isolated aorta. This effect was maximal at captopril doses of 1.0 mumol/kg body weight. When added directly into the incubation buffer, captopril at final concentrations of 50 and 500 nM also increased the synthesis of PGI2 by isolated rat aorta. Our results show that captopril stimulates PGI2 synthesis in vascular tissue and that this effect may be due at least in part to a direct action of this substance.

Angiotensin I↗
PubMed1978

Involving community representatives in CMHC evaluation and research.

The participation of community representatives and consumers of services in agency planning has been mandated by legislation and the subsequent regulations. However, the representatives' lack of technical knowledge and sophistication frequently makes them unequal participants in the decision-making process. To help increase such sophistication, the program analysis and evaluation section of a large community mental health center has involved or assisted patient and community volunteers in various evaluation and research projects; they include a survey of area housing conditions, a survey of the needs of former inpatients, an evaluation of programs operated by a coalition of community groups, and a community resource listing.

Community Mental Health Services↗
PubMed1978

The influence of PSROs.

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Community Mental Health Services↗
PubMed1977

Possible programmatic consequences of community mental health center funding arrangements: illustrations based on inpatient utilization data.

Funding arrangements have a direct and substantial influential effect on the delivery of mental health services. Despite the original intent of the community mental health center philosophy, centers have not been freed from programmatic limitations imposed by the fiscal systems. The focus of this article is the inpatient unit that has the key role as relates to a center's ability to raise revenue. Using data from a study of community mental health center inpatient utilization patterns, the authors demonstrate that centers face the problem of becoming revolving doors (for a recidivist population). Existing fiscal arrangements, it is suggested, reinforce this pattern and tend to downplay innovative alternatives to traditional inpatient care.

Ambulatory Care↗
PubMed1975

Attitudes of mental health center staff toward community organization.

The authors report on the differences in attitudes and perceptions that clinical and community organization staff have about the role of community organizers in a mental health center and about the center's priorities. Community organizers defined their role as one enabling the community to act on social-welfare problems, while clinical staff defined it as a liaison role connecting community residents and clinical services. Community organizers placed less value on traditional services, and felt greater dissatisfaction with center priorities.

Allied Health Personnel↗