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Biomedical subjects

E Friedman

Publications and source records attributed to E Friedman.

At least 379 records · Page 21Linked to original sources
PubMed1989

Effect of age on brain cortical protein kinase C and its mediation of 5-hydroxytryptamine release.

The effects of age on the activity and translocation of protein kinase C (PKC) and on the facilitation of 5-hydroxytryptamine (5-HT, serotonin) release induced by PKC activation with the phorbol ester phorbol 12-myristate 13-acetate were investigated. The activities of cortical PKC and its translocation in response to K+ depolarization and phorbol ester stimulation were reduced during aging in Fischer-344 rats. Parietal cortical brain slices from 6-, 12-, and 24-month-old animals were preloaded with [3H]5-HT and release was evoked by 65 mM K+ or the calcium ionophore A23187. 5-HT release induced by either K+ or A23187 was found to be reduced in 12- and 24-month-old as compared to 6-month-old animals. This decrease was not reversed by high extracellular Ca2+. Activation of PKC resulted in a facilitated transmitter release in tissue from 6- and 12-month-old animals but reduced [3H]5-HT release in slices from 24-month-old animals. These responses were prevented by the putative PKC inhibitor 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), but not by increasing extracellular or intracellular Ca2+. The results demonstrate an age-related change (1) in brain PKC activity and translocation and (2) in a physiological response to PKC stimulation. These results may have implications for other PKC-mediated functions that are altered during senescence.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1989

Swan song. A disastrous decade bows out.

The 1980s was a decade of disaster marked by three major themes. One was the idea of the market--the notion that economic principles such as competition, free-market pricing, deregulation, and consumer choice could be retrofitted to healthcare. The second featured myths that had little basis in reality but which were hauled out as justification for strange, destructive behavior. The third was the search for meaning in healthcare, which delved into the ethics and responsibilities of providers, policymakers, and patients, as well as the nature of healthcare. The results have not been all negative, however. A more careful brand of medicine is emerging--more conservative, more patient oriented, more sensitive, less cavalier. A more informed patient, who operates less on faith and more on questions, has already emerged. And hospitals, after a long sleep, have realized that their fate lies as much in the hands of the communities they serve as in the legislative halls of Washington or state capitals.

Bioethics↗
PubMed1989

Importance of central nervous system serotonin-1A receptors for mediating the hypotensive effect of urapidil.

Urapidil is thought to lower blood pressure by both a peripheral and a central mechanism. The former effect is caused by blockade of alpha-1 adrenoceptors whereas the latter effect has been shown to occur in the medulla, specifically at the intermediate area on the ventral surface of the medulla. The receptor mediating the central effect is not the alpha-1 adrenoceptor, but has been postulated to be the serotonin (5-HT)1A receptor. To determine whether urapidil lowers blood pressure by stimulating 5-HT1A receptors at the intermediate area, we applied urapidil bilaterally (50 micrograms/side) to the intermediate area of chloralose-anesthetized cats while monitoring arterial blood pressure and heart rate. Application of urapidil caused decreases in mean blood pressure and heart rate of 66 +/- 8 mm Hg and 31 +/- 7 beats/min, respectively. Pretreatment with the 5-HT1A and 5-HT2 receptor antagonist, spiperone (30 micrograms/side), counteracted the effects of urapidil. Pretreatment with the 5-HT2 receptor antagonist, ketanserin, did not alter the hypotensive effect of urapidil. Urapidil given i.v. in a dose of 2 mg/kg decreased mean blood pressure and heart rate by 53 +/- 6 mm Hg and 10 +/- 2 beats/min, respectively. At the peak of the i.v. response, spiperone (30 micrograms/side) was applied to the intermediate area and increased mean blood pressure and heart rate by 52 +/- 6 mm Hg and 20 +/- 4 beats/min, respectively, thus effectively reversing the effects of i.v. urapidil.(ABSTRACT TRUNCATED AT 250 WORDS)

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1988

Effects of psyllium fiber and short-chain organic acids derived from fiber breakdown on colonic epithelial cells from high-risk patients.

The effect of a purified fiber, psyllium and the short-chain organic acids derived from fiber breakdown, were assayed on isolated colonic epithelial cells primary-cultured from patients at high-risk of colon cancer, due to adenoma growth or family history of colon cancer. Psyllium fiber provided colonocytes some protection from deoxycholic acid-induced lysis. Propionic acid, a product of fiber breakdown, was a potent colonocyte mitogen, suggesting that fiber could indirectly protect the colon by providing colonocyte nutrients.

Adult↗
PubMed1988

Scopolamine modulates apomorphine-induced behavior in rats treated with haloperidol or SCH 23390.

In acute experiments, scopolamine (1.0 mg/kg) potentiated apomorphine stereotypy and inhibited the antistereotypic effect of both haloperidol (0.5 mg/kg) and SCH 23390 (0.2 mg/kg). Daily administration of either haloperidol (0.5 mg/kg) or SCH 23390 (0.2 mg/kg) for 3 weeks produced enhanced stereotypic responses to apomorphine. Co-administration of scopolamine (1.0 mg/kg) with haloperidol or SCH 23390 significantly reduced the behavioral supersensitivity produced by haloperidol or SCH 23390 alone. It is suggested that both D-1 and D-2 dopamine receptors are linked to a cholinergic mechanism.

Animals↗
PubMed1988

Sinus arrest associated with clonidine therapy.

A 65-year-old male with diabetes, hypertension, and mild renal failure developed dizziness and syncope one week after starting clonidine 0.45 mg/day. A continuous ECG recording revealed sinus bradycardia, nodal rhythm, and multiple episodes of sinus arrest lasting up to 4.5 seconds. Upon discontinuation of clonidine, serial continuous ECG recordings revealed gradual decrease in the number and duration of the sinus arrest episodes, until their complete disappearance shortly after the third day off clonidine. This report shows that clonidine may cause a concentration-dependent sinus node dysfunction in addition to the atrioventricular (AV) node abnormalities previously ascribed to it.

Aged↗
PubMed1988

Non-Hodgkin's lymphoma complicating acute lymphoblastic leukemia in remission.

Second malignancies occurring in patients cured of childhood acute lymphoblastic leukemia (ALL) are rare but increasingly recognized. There are only three reported cases of non-Hodgkin's lymphoma complicating ALL in remission. We report here another case of B-cell-type large-cell lymphoma, presenting in the uterus of a 24-year-old woman, 16.5 years after the diagnosis of ALL was made. Although immune markers of the ALL were not available, it was thought to be unlikely that the second malignancy was a relapse of the original tumor. Due to the long latency period and the minimal exposure to alkylating agents, the role of chemotherapy seems to be insignificant in this case. The development of a second malignancy could be a manifestation of the basic susceptibility to cancer.

Adult↗