Infusion of GDNF into the cerebral spinal fluid through two different routes: effects on body weight and corticospinal neuron survival.

Survival of axotomized adult rat corticospinal neurons (CSN) is supported by glial cell line-derived neurotrophic factor (GDNF). We have evaluated the trophic effects of intrathecally applied GDNF on CSN survival and rat body weight. Body weight reduction is the major side effect of intracerebral neurotrophic factor treatment. GDNF was tested at total doses of 30, 100 and 300 microg over 7 days after axotomy via different application routes: intracerebroventricularly (i.c.v.) and cisternally (cis). Animals injected i.c.v. displayed severe body weight reduction at all doses tested but CSN rescue only at the highest dose. In contrast, cis-infusion of GDNF promoted CSN survival at all doses and only the highest dose reduced the body weight. These results show that intracisternal, but not i.c.v., GDNF infusion at low doses can promote CSN survival without negatively affecting rat body weight. This finding may have implications for the clinic use of GDNF.

GDNF is a trophic factor for adult rat corticospinal neurons and promotes their long-term survival after axotomy in vivo.

Glial cell line-derived neurotrophic factor (GDNF) is a trophic factor for several neuronal populations involved in motor control. The present study evaluates the trophic actions of GDNF on corticospinal neurons, an important central nervous system motor projection into the spinal cord. Death of spinal motoneurons and corticospinal neurons is observed in the neurodegenerative disease amyotrophic lateral sclerosis. Axotomy of adult rat corticospinal neurons at internal capsule levels induces half of them to die, and the surviving population displays severe atrophy. To examine the trophic effects of GDNF on corticospinal neurons, Fast Blue-labelled corticospinal neurons were stereotaxically axotomized at internal capsule levels and GDNF was infused intracortically to lesioned corticospinal neurons at total doses of 2, 4, 10, 20, 40, 100 and 300 microg for 7 days. GDNF prevented axotomy-induced death of corticospinal neurons at doses between 2 and 40 microg and abolished or attenuated their atrophy at all doses examined. In addition, treatment with 8 microg GDNF for the first 2 weeks after axotomy resulted in the long-term survival of corticospinal neurons for 42 days. With regard to the development of treatment strategies for upper motoneuron degeneration in amyotrophic lateral sclerosis, application of GDNF via the cerebrospinal fluid may be more relevant than intracortical delivery as its diffusion within the brain parenchyma is limited. Intraventricular as well as intracisternal infusion of GDNF (300 microg over 7 days) completely prevented corticospinal neuron death. These results show that GDNF promotes the long-term survival of corticospinal neurons and has a positive effect on their size in vivo. Furthermore, the survival-promoting effect of GDNF on corticospinal neurons after delivery via cerebrospinal fluid has important clinical implications for potential treatment of the upper motoneuron degeneration seen in amyotrophic lateral sclerosis.

Penicillin V and rifampin for the treatment of group A streptococcal pharyngitis: a randomized trial of 10 days penicillin vs 10 days penicillin with rifampin during the final 4 days of therapy.

To improve the bacteriologic and clinical cure rates of streptococcal pharyngitis, 79 children were randomly assigned to receive penicillin V alone for 10 days (39 patients) or penicillin for the same duration and rifampin during the last 4 days of penicillin therapy (40 patients). Eleven patients given penicillin had evidence of bacteriologic failure (including eight with relapse of clinical illness) on repeat cultures done 4 to 7 days after treatment, whereas there were no failures in children given combination therapy (P = 0.0015). All eight symptomatic children improved with penicillin-rifampin therapy and subsequent cultures were negative, whereas three asymptomatic children continued to harbor group A streptococci even after combination therapy. Antibody response by antistreptolysin O or antideoxyribonuclease B assay was seen in 50.6% of patients; the antibody responses in both groups were comparable. These results show that addition of rifampin to the penicillin regimen improves the clinical and bacteriologic cure rates in children with streptococcal pharyngitis.