"Fatal Gastrointestinal and Peritoneal Ischemic Disease" of Unknown Cause at Arba Minch Hospital, Southern Ethiopia

Gastrointestinal and peritoneal ischemic disease due to unknown etiology present with intestinal obstruction and/or peritonitis otherwise in healthy patient emerged as fatal disease at Arba Minch General Hospital. This disorder was diagnosed based on intraoperative finding. Clinical presentation and natural history of disease progression were similar. It is estimated that about 6-10 lives are being claimed each year at Arba Minch Hospital with this disease of unidentified cause accounting for the largest figure of surgical department. Here we report case analysis and literature review illustrating clinical presentation, workup, preoperative diagnosis, intraoperative diagnosis, and final outcome of fatal gastrointestinal and peritoneal ischemic disease.

Arginine uptake by isolated rat liver mitochondria

The question of arginine uptake by mitochondria is important in that arginine is an allosteric effector of N-acetylglutamate synthetase. Thus, changes in mitochondrial arginine concentration have the potential for acutely modifying levels of N-acetylglutamate, a compound necessary for maximal activity of carbamyl phosphate synthesis. Mitochondria were isolated from chow-fed rats, incubated with [guanido-14C]arginine and were centrifuged through silicon oil into perchloric acid for determination of intramitochondrial metabolites. Arginine was separated from urea by cation-exchange resin. Mitochondrial water space was determined by [14C]urea arising from arginase activity associated with the mitochondrial preparations. Extramatrix space was determined by parallel incubations with [inulin-14C]carboxylic acid or [14C]sucrose. There was considerable degradation of arginine by arginase associated with the mitochondrial preparation. This was inhibited by 7 mM ornithine and 7 mM lysine. Arginine was concentrated intramitochondrially to 4-times the extramitochondrial levels. The concentration ratio was decreased in the presence of ornithine and lysine but not with citrulline, NH4Cl, glutamate, glutamate or leucine. No uptake was observed when mitochondria were incubated at 0 degree C. Mitochondria did not concentrate citrulline.

Discrimination of speech processed by low-pass filtering and pitch-invariant frequency lowering

Consonant discriminability by normal-hearing listeners was studied for monosyllables processed using frequency lowering with either uniform (linear) or nonuniform (warped) compression of the frequency axis. The bandwidth of the compressed signal was either 2500 or 1250 Hz and five compression characteristics were studied, in addition to low-pass filtering, for each of the two bandwidths. Stimuli were 24 consonant-vowel syllables made up of 24 consonants and three vowels, recorded three times by each of two male and female speakers. A "roving-speaker, roving-vowel, roving-utterance," two-interval, forced-choiced procedure with feedback was employed. As expected, performance for the 2500-Hz bandwidth was superior to that for the 1250-Hz bandwidth. For each bandwidth, compression schemes which accomplished greater lowering of the high frequencies relative to the low frequencies resulted in the highest performance. Overall performance for the best frequency-lowering system studied, however, was roughly comparable to that obtained for low-pass filtering. Patterns of performance over articulatory features were different for frequency lowering and filtering. In general, lowering was superior to filtering for contrasts of fricative sounds but inferior for contrasts of nasals and semivowels.