Biomedical subjects
B S Spinowitz
Publications and source records attributed to B S Spinowitz.
Action of adenosine on chloride active transport of isolated frog cornea.
Addition of adenosine (10-7 to 10-4 M) to the tear side of isolated corneas (Rana catesbeiana) produced a rapid, sustained increase in short-circuit current, potential difference, and radioisotopic chloride net flux. The increased net chloride flux accounted for the increased short-circuit current. Adenosine, a known activator of adenyl cyclase in other tissues, exerted its effects on chloride transport through a receptor different from the one described for epinephrine and prostaglandins in the corneal epithelium. Propranolol inhibited the epinephrine response but not the adenosine effect. Dipolyphloretin phosphate inhibited prostaglandin responses but did not affect the adenosine stimulation of chloride transport. Adenine and/or ribose, parts of the adenosine molecule, had no stimulatory effect, but 5'-AMP had a partial effect. The activation of the chloride pump with DBcAMP blocked the response to adenosine. Adenosine interacted with the effects of theophylline. Adenosine, a naturally occurring molecule, stimulated chloride transport by activation of adenyl cyclase through a separate membrane receptor in the corneal eqithelium.
Increased production of fructose by the brain in dogs made diabetic by alloxan and by growth hormone.
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Effect of long-term epoetin beta therapy on the quality of life of hemodialysis patients.
Differences in quality of life were observed using two separate patient populations with end-stage renal disease who were on maintenance hemodialysis. The first population (91 patients) received epoetin beta (Marogen Sterile Powder, Chugai-Upjohn, Inc., Chicago, Ill.) for an average of 18 months. The second population (96 patients) did not receive this therapy. The measured quality of life parameters included a number of global and psychological well-being measurements and the Sickness Impact Profile (SIP), as well as energy, activity levels, appetite, work, and sexual function. When adjusted for covariates (health status and demographics), 16 of 26 parameters were significantly higher (p less than .05) in patients receiving epoetin beta. All mean scores for global measurements were significantly higher. Significantly higher scores were also obtained for total SIP and total psychosocial subscale, as well as for sleep, home management, recreation, emotional behavior, social interaction, ability to work, and energy. While not statistically significant, all of the remaining measurements were higher for epoetin beta than for untreated patients.
Potential angiotensin-converting enzyme inhibitor-epoetin alfa interaction in patients receiving chronic hemodialysis.
We compared epoetin alfa (EPO) dose requirements and hematocrit response in 17 patients receiving chronic hemodialysis at baseline and after 3 and 12 months of therapy with angiotensin-converting enzyme (ACE) inhibitors (12 enalapril, 5 captopril). No acute processes were present (infection, hemorrhage, inflammation) at time of starting ACE inhibitor therapy. Mean (+/- SD) intravenous EPO dosages at zero, 3, and 12 months were 6012 +/- 2575, 5800 +/- 2026, and 5660 +/- 2285 U 3 times/week (p=0.56), and mean differences were -212 U for 0-3 months (95% CI -1310 to 886) and -713 U for 0-12 months (95% CI -2142 to 716). Mean +/- SD hematocrits were 30.5 +/- 3.9%, 31.6 +/- 3.2%, and 34.2 +/- 3.1% (p=0.01, zero vs 12 mo), and mean differences were 1.7% for 0-3 months (95% CI -1.41 to 4.81) and 3.85% for zero-12 months (95% CI 0.71-7). Our results indicate that ACE inhibitors do not increase EPO dose requirements or reduce hematocrits in these patients.