The investigation reported in this paper rendered mainly two results which are of importance for the analysis of photosynthesis in chlorophyllous plants. Firstly: Unicellular algae (Scenedesmus and similar species), which under anaerobic conditions are capable of reducing carbon dioxide with molecular hydrogen in the light, will liberate hydrogen slowly in the dark if air is replaced by nitrogen in the surrbunding gas phase. This faculty for a hydrogen fermentation in Scenedesraus agrees with our knowledge of the dark metabolism of bacteria which utilize hydrogen. These reactions with hydrogen have often been found to be reversible. Secondly: Illumination of the fermenting algae enhances the liberation of hydrogen, particularly if the substrates of the' photochemical reduction process, carbon dioxide and hydrogen, are both absent. The release of hydrogen by the algae under the influence of light occurs at a rate about ten times that of the hydrogen formation in the dark. The rate, however, is already limited at low intensities by factors other than the light intensity. Experiments with specific inhibitors, like dinitrophenol, allow us to differentiate between the dark and the photochemical liberation of hydrogen.Upon return of the photosynthesizing cell to aerobic conditions both phenomena disappear as in the case of photoreduction.Besides hydrogen and carbon dioxide, the anaerobic metabolism of Scenedesmus and of similar green algae includes many other substances, notably organic acids formed by fermentation of internal or artificially provided carbohydrates. As far as the nature of these fermentation products is concerned, the present investigation was extended only to the analysis of added glucose and to the identification and determination of lactic acid. MethodsA description of the methods used in the present study has been reported elsewhere (Jack Rubin (27)), so that a few summarizing remarks will suffice.Pure cultures of Scenedesmus species D1, S. species D3, and S. obl~tuus were grown at 20°C. in inorganic saline through which a slow stream of 4 per cent CO2 in air was passed. The culture flasks, each containing 200 co. of medium, were inoculated from an agar slant and illuminated for 3 to 4 days with incandescent lamps yielding about 4,000 lux at the bottom of the flasks. The gas exchange of the algae was determined by Warburg's manometric method 219

We initiated a therapeutic program of continuous ambulatory peritoneal dialysis for patients with chronic renal failure. Our program resulted in many episodes of peritonitis arising from contamination due to the technical aspects of the procedure. Microbiologic evaluation showed that 73% of 97 episodes were culture positive, with gram-positive organisms causing most of the cases, especially early in dialysis. Gram-negative rods tended to occur later. Gram stains of dialysate effluent resulted in a disappointingly low yield of only 9% positivity. Cell counts were a dependable indicator of the presence of peritoneal inflammation and also of therapeutic success. Most patients responded well to intraperitoneal cephalothin, 125 mg/L for 10 to 14 d. The occurrence of peritonitis resulted in 0.93 years of hospitalization during the total of 15.45 patient-years on dialysis, which essentially negated the financial advantages of this method of treatment of chronic renal failure. For this to be a successful mode of therapy, advances in the prevention of peritonitis must be made.

Background and objectives The calcimimetic cinacalcet reduced the risk of death or cardiovascular (CV) events in older, but not younger, patients with moderate to severe secondary hyperparathyroidism (HPT) who were receiving hemodialysis. To determine whether the lower risk in younger patients might be due to lower baseline CV risk and more frequent use of cointerventions that reduce parathyroid hormone (kidney transplantation, parathyroidectomy, and commercial cinacalcet use), this study examined the effects of cinacalcet in older ($65 years, n=1005) and younger (,65 years, n=2878) patients.Design, setting, participants, & measurements Evaluation of Cinacalcet HCl Therapy to Lower Cardiovascular Events (EVOLVE) was a global, multicenter, randomized placebo-controlled trial in 3883 prevalent patients on hemodialysis, whose outcomes included death, major CV events, and development of severe unremitting HPT. The age subgroup analysis was prespecified.Results Older patients had higher baseline prevalence of diabetes mellitus and CV comorbidity. Annualized rates of kidney transplantation and parathyroidectomy were .3-fold higher in younger relative to older patients and were more frequent in patients randomized to placebo. In older patients, the adjusted relative hazard (95% confidence interval) for the primary composite (CV) end point (cinacalcet versus placebo) was 0.70 (0.60 to 0.81); in younger patients, the relative hazard was 0.97 (0.86 to 1.09). Corresponding adjusted relative hazards for mortality were 0.68 (0.51 to 0.81) and 0.99 (0.86 to 1.13). Reduction in the risk of severe unremitting HPT was similar in both groups. ConclusionsIn the EVOLVE trial, cinacalcet decreased the risk of death and of major CV events in older, but not younger, patients with moderate to severe HPT who were receiving hemodialysis. Effect modification by age may be partly explained by differences in underlying CV risk and differential application of cointerventions that reduce parathyroid hormone.

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Three years of clinical experience with continuous ambulatory peritoneal dialysis are summarized. Serum urea nitrogen, creatinine, hematocrit, nerve conduction velocity, calcium, inorganic phosphorus, serum proteins, and electrolytes have been maintained in acceptable ranges. Peritonitis, although reduced in incidence because of solutions in plastic bags and a new adapter, is still a problem. Excessive carbohydrate absorption, obesity, and high serum triglyceride concentrations may be long-term problems in some patients.