Alpha-ketoglutaramate: increased concentrations in the cerebrospinal fluid of patients in hepatic coma

alpha-Ketoglutaramate, a deaminated metabolite of glutamine not previously identified in biological tissues, was measured in the cerebrospinal fluid of human subjects and found to be increased three- to tenfold in patients with hepatic coma. When perfused into the cerebral lateral ventricles of rats, alpha-ketoglutaramate (10 mM) depressed the animals' nocturnal locomotor activity, and at higher doses induced circling behavior and myoclonus. The concentration of alpha-ketoglutaramate in cerebrospinal fluid appears to be a reliable diagnostic indicator of hepatic coma, and its accumulation may contribute to the pathogenesis of this disease.     

INTERFERENCE BETWEEN ST. LOUIS ENCEPHALITIS VIRUS AND EQUINE ENCEPHALOMYELITIS VIRUS (WESTERN TYPE) IN THE CHICK EMBRYO

Interference between two unrelated viruses is reported. Equine encephalomyelitis virus grows only to a limited degree, if at all, when injected into chick embryos in which St. Louis encephalitis virus is being propagated.     

Somatosensory system: organizational hierarchy from single units in monkey area 5

The receptive fields of single cells in area 5 of monkey parietal cortex were studied by extracellular recording. Cells were driven primarily by gentle manipulation of multiple joints residing on one or more limbs. Both excitatory and inhibitory convergence were demonstrated. It is postulated that the multijoint receptive fields of area 5 are the result of convergence from single-joint cells of the primary receiving area. An analogy is drawn between the modification of information in the visual and somatosensory systems.     

Musculoskeletal responses of 2-year-old Thoroughbred horses to early training. 4. Morphometric,microscopic and biomechanical properties of the digital tendons of the forelimb

AIM: To determine the weight, volume, density and cross-sectional area (CSA) of the digital flexor tendons, common digital extensor tendon (CDET) and suspensory ligament (SL) of the forelimb of young Thoroughbred horses in early training, and to assess the response to a training programme of known parameters of superficial digital flexor tendon (SDFT) tissue at mid-metacarpal level.

METHODS: The tendons of seven 2-year-old Thoroughbred horses in training were inspected, transected into segments of known length, and compared with those from seven untrained horses matched for age, sex and breed. The weight, volume, density and CSA of each segment, and the crimp angle, histological features, and biomechanical ultimate stress and stiffness of tendon samples from the mid-metacarpal region of the SDFT were determined.

RESULTS: There was no macroscopic evidence of swelling or discolouration in any of the tendon segments or cut surfaces. The volumes of SDFT and CDET segments of horses in the trained group were significantly greater than those in the untrained group (p=0.036 and p=0.039, respectively). A greater increase in volume than weight resulted in a lower density in the SDFT but not CDET in trained compared with untrained horses (p=0.038). CSA of these two tendons was significantly greater in the trained group (p=0.002 and 0.036, respectively), the percentage increase being greater in the CDET than the SDFT. The number of tenocytes at four sites in the mid-metacarpal SDFT region was less in trained than untrained horses (p=0.025). There was no histological evidence of inflammation, and no difference in crimp angle between groups. There was no significant between-group difference in stiffness or ultimate stress of tendon strips.

CONCLUSIONS: Volume and CSA of the SDFT and CDET were larger in trained than untrained horses. The SDFT was less dense in the trained group. Because no evidence of tendonitis was detected and training appeared to have no significant effect on crimp angle or biomechanical properties of tendon strips, the size and density changes were presumed to be adaptive and induced by the training.

CLINICAL RELEVANCE: Although evident in this in vitro study, the detection of adaptive from initial pathological increase in size of the SDFT is likely to be difficult in vivo.