Arginase isoforms in frog and lizard tissues.

Isoforms of arginase in the liver and kidney tissues of the ureotelic frog (Rana tigerina) and uricotelic lizard (Calotes versicolor) were fractionated by DEAE-cellulose chromatography (pH 8.3). Four molecular forms, designated as A’1, A2, A3 and A4 based on the KCl concentration required for their elution from the ion-exchange column, were detected in lizard liver, while only two forms were found in lizard kidney (A3 and A4) and frog liver and kidney (A2 and A3). No major differences were found in the pH optimum, substrate affinity and molecular weight of the isoenzymes. The isoforms in lizard tissues were either totally unaffected or only partially immunoprecipitated by antibodies raised against rat liver and beef liver arginases, but those in frog tissues were significantly activated by the two antibodies. While the physiological importance of the presence of four isoforms in lizard liver remains enigmatic, different sets of isoenzymes were present in the liver of the two ureotelic vertebrates, rat and frog. Hence, it appeared that a given mode of nitrotelism was not associated with a specific set of isoenzymes. Also, the data were not consistent with the generally held view that a basic isoform of arginase served as a component of the urea cycle in liver and a neutral/slightly acidic form functions in the synthesis of proline, glutamate and polyamines in extra-hepatic tissues. The isoforms appeared to show considerable functional overlap.

Medialisation laryngoplasty: a new surgical frontier in the management of vocal cord paralysis.

Patients who are victims of vocal cord paralysis usually suffer from husky or hoarse voice which is very much jeopardising their future particularly in professional voice users like singers, priests, teachers, etc. Phonosurgical techniques like medialisation laryngoplasty has opened a new horizon in the management of dysphonia with unilateral vocal cord paralysis. Medialisation laryngoplasty is sometimes described under the heading of laryngoplastic phonosurgery or thyroplasty. A report of 10 cases of unilateral vocal cord paralysis with dysphonia subjected to medialisation laryngoplasty from March 1996 to March 1998 with 90% success is presented. Only one patient developed inspiratory stridor as a complication.

Allantoin excretion in snakes.

Allantoin, which is generally regarded as absent in the excreta of snakes, has been demonstrated in the urinary deposits of 7 species of snakes by a sensitive paper chromatographic method. It appears that allantoin is the end product of purine catabolism in these animals.