A possible interaction of vitamin C with the metabolism of drugs which are oxidized (e.g., antipyrine and diphenylhydantion) is indicated from data in animals. The effect of megadoses of vitamin C (300 mg/day to 4800 mg/day) was therefore tested in human volunteers receiving antiprine (single oral dose) or diphenlhydantoin (chronic therapy). The half-life, volume of distribution, and plasma clearance of antipyrine were not affected by vitamin C treatment. Steady-state plasma levels of diphenylhydantoin in two epileptic patients were similar before and during vitamin C (1.2 Gm/day for 18 days) treatment. It is concluded that vitamin C, in commonly used megadoses, has no effect on the metabolism of antipyrine or diphenylhydantoin in men.

Antipyrine↗

PubMedDate not supplied

Mondini dysplasia: spontaneous cerebrospinal fluid otorrhea. New perspectives in management.

The Mondini dysplasia represents a developmental arrest during the embryogenesis of the inner ear. The malformation, commonly associated with deafness, is frequently heralded by meningitis secondary to communication of the middle ear with the subarachnoid space. Early recognition and successful repair of the CSF leak is important to avoid the sequelae of repeated episodes of meningitis. We believe the addition of CSF diversion in the form of a lumbar drain during and after surgery will result in improved success.

Cerebrospinal Fluid Otorrhea↗

PubMedDate not supplied

Drug excretion in human breast milk: principles, pharmacokinetics and projected consequences.

The excretion of drugs in human breast milk is reviewed with regard to milk production, composition, feeding patterns and mechanisms of drug transfer into milk. Fundamental principles of breast milk excretion are used to construct a pharmacokinetic approach useful for the study of most drugs. An infant-modulated 3-compartment open model is proposed for drug distribution and elimination in the breast feeding woman. Milk/plasma drug concentration ratios are projected on the basis of pH partitioning. While some studies confirm these projections, other studies demonstrate a need to consider additional factors such as lipid solubility and protein binding characteristics of a drug in milk. Data are lacking for most drugs and hence dosing via milk or risk to the infant remains speculative. Very few pharmacokinetic studies of both milk and infant plasma were found. A review of selected drug classes cites available information as a basis for future studies. Few drugs are contraindicated in breast feeding women, but supportive data for either proscriptions or permissive statements are often lacking. A neglected but potentially serious infant risk--impaired behaviour and development--is discussed from the standpoint of emerging animal data. Conceptually valid and comprehensive studies on drug excretion in breast milk are needed if this valuable nutrient for infants is to be made available safely.

Absorption↗

PubMedDate not supplied

The relationship between neuropsychological function and brain damage detected by neuroimaging after closed head injury.

Studies relating neuropsychology and structural neuroimaging after closed head injury are reviewed. Particular attention is given to the question of the relative contribution of focal and diffuse damage to neuropsychological impairment. The evidence currently available emphasizes the importance of diffuse damage in closed head injury. Diffuse damage is not equally distributed in the brain, and the review suggests three axes that are relevant for neuropsychological function: (1) damage may be unilateral or bilateral, (2) damage is characteristically greater in anterior regions than posterior regions, and (3) damage shows a centripetal gradient. A large gap remains between the emergent generalizations concerning head injury and reliable neuropsychological interpretation of scans from individual patients.

Brain↗

PubMedDate not supplied

Intercorrelation of lesions detected by magnetic resonance imaging after closed head injury.

Forty-three patients with closed head injuries were followed up 5 to 12 months post-injury. Patients had magnetic resonance imaging (MRI) and performed a variety of neuropsychological tests. There were systematic relationships between lesions in different sites: depth of lesions in orbito-frontal regions, frontal regions, and temporal poles were particularly strongly intercorrelated. Depth of lesions in specific sites also correlated with an overall measure of brain damage: the number of areas with lesions present. After correcting for premorbid differences there were significant correlations between lesions in specific sites and scores on three out of five WAIS subtests. Scores on these three subtests also correlated significantly with overall brain damage. In general, hemispheric sites which were significantly related to neuropsychological measures also showed significant intercorrelations among themselves. The findings stress the importance of patterns of lesions in head injury, and emphasize the difficulty of showing differential localization of cerebral function in this population.

Adolescent↗

PubMedDate not supplied

MR imaging of spinal cord avulsion.

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Birth Injuries↗