The effects of clenbuterol beta(2)-agonist administration were investigated in normal and atrophied [15-day hindlimb-unloaded (HU)] rat soleus muscles. We showed that clenbuterol had a specific effect on muscle tissue, since it reduces soleus atrophy induced by HU. The study of Ca(2+) activation properties of single skinned fibers revealed that clenbuterol partly prevented the decrease in maximal tension after HU, with a preferential effect on fast-twitch fibers. Clenbuterol improved the Ca(2+) sensitivity in slow- and fast-twitch fibers by shifting the tension-pCa relationship toward lower Ca(2+) concentrations, but this effect was more marked after HU than in normal conditions. Whole muscle electrophoresis indicated slow-to-fast transitions of the myosin heavy chain isoforms for unloaded and for clenbuterol-treated soleus. The coupling of the two latter conditions did not, however, increase these phenotypical transformations. Our findings indicated that clenbuterol had an anabolic action and a beta(2)-adrenergic effect on muscle fibers and appeared to counteract some effects of unloading disuse conditions.

The effects of hypergravity (HG) on soleus and plantaris muscles were studied in Long Evans rats aged 100 days, born and reared in 2-g conditions (HG group). The morphological and contractile properties and the myosin heavy chain (MHC) content were examined in whole muscles and compared with terrestrial control (Cont) age-paired rats. The growth of HG rats was slowed compared with Cont rats. A decrease in absolute muscle weight was observed. An increase in fiber cross-sectional area/muscle wet weight was demonstrated, associated with an increase in relative maximal tension. The soleus muscle changed into a slower type both in contractile parameters and in MHC content, since HG soleus contained only the MHC I isoform. The HG plantaris muscle presented a faster contractile behavior. Moreover, the diversity of hybrid fiber types expressing multiple MHC isoforms (including MHC IIB and MHC IIX isoforms) was increased in plantaris muscle after HG. Thus the HG environment appears as an important inductor of muscular plasticity both in slow and fast muscle types.

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in the right temporal lobe. His memory seemed to improve slightly. By day 14 he was able to complete the serial sevens test accurately to 58.Complement-fixing antibody to herpes simplex virus (HSV) was found in all serum and CSF specimens (table). For samples taken on days 2 and 14, HSV IgG antibody was quantitated by radioimmunosorbent assay.' Albumin and IgG were determined by electroimmunoassay. The CSF:serum albumin ratio (measuring blood-CSF barrier function) was slightly elevated on day 2 but was within normal limits by day 14. The elevation of CSF:serum albumin ratio was not sufficient to invalidate index measurements.2 Intrathecal IgG synthesis was documented by an elevated IgG index in both specimens. Intrathecal synthesis of HSV-specific IgG antibody was demonstrated in both pairs of specimens by calculation of an HSV-specific antibody index (AI). An A1 of->1.9 is diagnostic of herpes encepha1itis.lTo confirm the diagnosis, CSF from days 2, 14, and 22 were examined for HSV DNA. DNA corresponding to a fragment of the HSV-1 thymidine kinase (TK) gene was specifically amplified using the polymerase chain r e a~t i o n ,~ and the presence of HSV TK gene-specific DNA confirmed by Southern blotting.3 HSV DNA was detected at days 2 and 14, but was absent at day 22.Psychometric assessment carried out 3 weeks after admission and 1 week after cessation of acyclovir therapy showed disturbance of visual and verbal memory functions and, particularly, impaired delayed recall. He could not recall the ages of his children, his address or how long he had been living there, his locality, or details of his employment extending back several years. Retrograde amnesia was estimated as extending for 3 to 4 years. He had marked anterograde amnesia. He was disorientated as to time, unable t o give any account of recent events, and unable to learn new information. He retained insight and there was no confabulation. Personality was intact. Tests of frontal lobe function, language, perception, attention, and concentration were normal, and his full-scale I& was assessed to be in the high average range at 113. A significant feature of his memory disturbance was a positive response to cueing, indicating a deficit of retrieval rather than storage o r encoding of information. He and his wife were given advice in the use of practical

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