No abstract

Four ceftazidime-resistant Escherichia coli strains were isolated from elderly nursing home patients in a New York hospital during 1993. Strains MCQ-2, MCQ-3, and MCQ-4 were determined to be identical by pulsed-field gel electrophoresis and plasmid profiles, whereas strain MCQ-1 was unique. Strain MCQ-1 was determined to produce a TEM-10 beta-lactamase. Strains MCQ-2, MCQ-3, and MCQ-4 were also noted to be resistant to cefotaxime. These three strains produced two beta-lactamases with pIs of 5.4 (TEM-1) and 7.6. beta-Lactamase assays revealed that the pI 7.6 enzyme hydrolyzed cefotaxime faster (at a relative hydrolysis rate of 30% compared with that of benzylpenicillin) than either ceftazidime or aztreonam (relative hydrolysis rates of 13 and 3.3%, respectively). Nucleotide sequencing of the gene encoding the pI 7.6 beta-lactamase from strain MCQ-3 revealed a blaSHV-type gene differing from the gene encoding SHV-1 at four nucleotides which resulted in amino acid substitutions: phenylalanine for isoleucine at position 8, serine for arginine at position 43, serine for glycine at position 238, and lysine for glutamate at position 240. This novel SHV-type extended-spectrum beta-lactamase is designated SHV-7.

~Two new glycowithanolides, sitoindoside IX (1) and sitoindoside X (Z), isolated from Withuniu somniferu Dun., were evaluated for their immunomodulatory and CNS effects (anti-stress, memory and learning) in laboratory animals, because the plant extract is used by practitioners of the Indian systems of medicine for similar purposes. The two compounds, in doses of 100-400 & n o u s e , produced statistically significant mobilization and activation of peritoneal macrophages, phagocytosis and increased activity of the lysosomal enzymes secreted by the activated macrophages. Both these compounds (50-200 mg/kg p.0.) also produced significant anti-stress activity in albino mice and rats and augmented learning acquisition and memory retention in both young and old rats. These findings are consistent with the use of W . somniferu, in Ayurveda, to attenuate cerebral function deficits in the geriatric population and to provide non-specific host defence.

Twenty-four patients with Guillain-Barré syndrome were prospectively evaluated for evidence of autonomic dysfunction. It occurred in 16 (66.7%) patients, usually during the peak period of paralysis, in the form of either excess or inadequate activity of sympathetic and/or parasympathetic nervous systems. Its clinical manifestations comprised of sinus tachycardia (33.3%), bradycardia (8.3%), hypertension (33.3%), postural hypotension (35%), urinary sphincteric disturbances (20.8%) and anhydrosis of lower limbs (12.5%). Assessment of cardiovascular responses to autonomic function tests revealed impaired alterations in heart rate during deep breathing (31.6%), Valsalva's manoeuvre (28.6%), sustained handgrip (25%), cold-pressor test (36.4%), postural change (35%) and atropine test (20%); and impaired rise in blood pressure during firm handgrip (25%) and cold-pressor test (36.6%). ECG abnormalities were noticed in 8 (33.3%) patients. They comprised of depressed ST segment in 5, inverted T wave in 3, tall T wave in 2 and prolonged QTc in 2 patients. Two patients died of respiratory failure. Autonomic dysfunction in Guillain-Barré syndrome did not appear to have any prognostic significance as there was no significant difference in autonomic dysfunction between good - and bad - outcome groups of patients.