Targeted Knockdown of GDCH in Rice Leads to a Photorespiratory-Deficient Phenotype Useful as a Building Block for C4 Rice.

The glycine decarboxylase complex (GDC) plays a critical role in the photorespiratory C2 cycle of C3 species by recovering carbon following the oxygenation reaction of ribulose-1,5-bisphosphate carboxylase/oxygenase. Loss of GDC from mesophyll cells (MCs) is considered a key early step in the evolution of C4 photosynthesis. To assess the impact of preferentially reducing GDC in rice MCs, we decreased the abundance of OsGDCH (Os10g37180) using an artificial microRNA (amiRNA) driven by a promoter that preferentially drives expression in MCs. GDC H- and P-proteins were undetectable in leaves of gdch lines. Plants exhibited a photorespiratory-deficient phenotype with stunted growth, accelerated leaf senescence, reduced chlorophyll, soluble protein and sugars, and increased glycine accumulation in leaves. Gas exchange measurements indicated an impaired ability to regenerate ribulose 1,5-bisphosphate in photorespiratory conditions. In addition, MCs of gdch lines exhibited a significant reduction in chloroplast area and coverage of the cell wall when grown in air, traits that occur during the later stages of C4 evolution. The presence of these two traits important for C4 photosynthesis and the non-lethal, down-regulation of the photorespiratory C2 cycle positively contribute to efforts to produce a C4 rice prototype.

Treatment of myocardial infarction in a community hospital coronary care unit. Experience with 1,246 patients.

The hospital mortality in 1,246 consecutive acute myocardial infarction patients treated in a large community hospital coronary care unit was 14.4%. Of the total, 52.3% showed no evidence of heart failure, 25.8% had mild to moderate failure, 9.9% had pulmonary edema, and 12% developed cardiogenic shock; the mortality in these groups was 2.2%, 7.4%, 8.9%, and 87.2%, respectively. The mortalitiy in the 1,097 patints who did not have cardiogenic shock was 4.5%. Only one patient died as a result of primary ventricular fibrillation (0.08%). The mortality of complete heart block in the absence of cardiogenic shock (8.3%) was not significantly different from that of comparable patients who did not have complete heart block (4.3%). These results are lower than those generally reported.

Carbenicillin in the first nine months of unrestricted use. A chapter in the natural history of an antibiotic.

During the first nine months following its release for general use, carbenicillin was administered to forty-two patients in Hahnemann Hospital. Thirty-nine available records of patients receiving the drug for other than urinary infection were reviewed. Among children, all but one had mucoviscidosis: most were given acceptable therapeutic regimens; survival rate was 80%, and their physicians were favorably impressed. Among adults, underlying disease was usually life threatening; most were inadequately treated; survival rate was 31%, and their physicians were not favorably impressed. The multiplicity of variables precludes objective evaluation of the drug under the circumstances of its use, but one that could have been avoided was the inconsistency of the therapeutic regimen, which in adult patients was too often insufficient. As used, therefore, carbenicillin has not provided the benefits predicted from its earlier controlled evaluation, and the large expenditure of money, particularly by adult patients, has been largely wasted.