Biomedical subjects
Publications and source records attributed to L E Davis.
Forty-nine children with complicated bacterial meningitis were studied. Thirteen had abnormalities on computed tomography compatible with the diagnosis of brain infarction; one had a brain biopsy with the histological appearance of infarction. Factors exist in childhood bacterial meningitis which are associated with the development of brain infraction.
The incidence and prevalence of multiple sclerosis (MS) in Los Alamos County, New Mexico, were investigated because the number of reported cases appeared to have increased. The point prevalence on November 1, 1979, was 75.7 per 100,000, and average annual incidence rates for the period 1960-1969 and 1970-1979 were 3.4 and 3.7 per 100,000, respectively. The rates of MS in Los Alamos County were greater than expected from previous epidemiologic surveys of North America. The unusual ethnic composition and high socioeconomic level of the population probably contributed to the increases.
Newborn hamsters and kittens infected with vaccinia virus developed communicating hydrocephalus without fibrotic changes in the meninges. Following intracerebral viral inoculation, a transient inflammation of the meninges, ependyma, and choroid plexus was found. One month later, 70% of hamsters infected with the WR strain of vaccinia virus and 35% infected with the vaccine strain developed hydrocephalus. The mechanism of hydrocephalus production is unclear, but differs from other models in which it is associated with stenosis of the aqueduct of Sylvius or fibrosis of the subarachnoid space.
The inner ears obtained from an infant who died of severe congenital cytomegalovirus infection were examined using virological and morphological methods. The techniques of microdissection and surface preparations, immunofluorescent microscopy, and transmission and scanning electron microscopy were employed. Cytomegalovirus was isolated from the perilymph. Injury to the cochlea was minor and was confined to the first half of the basal turn. There were signs of a severe labyrinthitis of the vestibular endolymphatic system. Vestibular organs, especially the saccule and utricle, showed severe damage, with collapse of the saccular membranous wall. Inclusion-bearing cells containing cytomegalovirus antigen, as shown by immunofluorescent staining, and cytomegalovirus virions, as observed by electron microscopy, were found on the endolymphatic surface of the membranous walls, mainly in the saccule and utricle. In the utricle, the infected cells appeared to be concentrated in the regions where the so-called dark cells were located. These dark cells are similar to the proximal tubule cells in the kidney, another common target for cytomegalovirus infection.
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Although botulinum toxin is thought not to affect the human CNS, previous studies have not examined those behaviors, such as memory, that have been shown to be dependent on central acetylcholine transmission. In eight patients with type A botulism, subjective analysis, bedside memory testing, and formal memory testing with Hebb's verbal sequencing test, Corsi's nonverbal sequencing test, and Buschke's verbal serial list learning test failed to demonstrate impairment in immediate and recent memory. Botulism severe enough to block peripheral nicotinic and muscarinic cholinergic transmission does not block those central cholinergic synapses involved in memory.
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We report fatal Reye's syndrome in two adults following proven influenza A viral infections. Reye's syndrome is, therefore, not confined to children but may also occur in adults. Many reported cases of postinfluenza A encephalopathy have clinical and pathological features of Reye's syndrome suggesting that they are not due to postinfectious perivenous demyelination.
Guillain-Barré syndrome and the nephrotic syndrome developed in a patient simultaneously. Analysis of renal biopsy by light, immunofluorescent, and electron microscopy showed lipoid nephrosis. T-cell lymphocytopenia, lymphocytotoxic antibodies, depressed lymphocyte mitogenesis, and anergy also complicated the illness. The immunologic abnormalities resolved when the polyradiculoneuritis and lipoid nephrosis remitted. This previously undescribed association illustrates the occurrence of two postulated cell-mediated autoimmune disorders despite the presence of depressed cell-mediated immunity.
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Cerebrospinal fluid samples from 44 pregnant women undergoing spinal anesthesia for delivery were studied to determine whether an abdomen distended with a full-term fetus could alter the dynamics of lumbar CSF. The mean CSF values for opening pressure, CSF cell count, and protein concentration were all normal.
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Although the fluorescent treponemal antibody absorption (FTA-ABS) test has found wide application in the diagnosis of syphilis, the cerebrospinal fluid fluorescent treponemal antibody (CSF-FTA) test is still controversial in the diagnosis of neurosyphilis. We found the CSF-FTA test extremely sensitive to contamination with FTA-ABS-reactive blood at concentrations in CSF that could not be detected by visual inspection. Interpretation of a reactive test should be made with caution if red cells are present in CSF.
In a double-blind crossover study in which patients received placebo or active drug for varying periods, we evaluated the ability of guanidine hydrochloride (20 to 35 mg/kg per day perorally) to improve the rate of recovery in patients with moderate or severe botulism, type A, intoxication. Among 14 patients who received conventional botulism therapy, there was no improvement in recovery rate in those who received guanidine compared with the nontreated group. Individual patients in the treated group showed neither an acceleration in their rate of improvement when they received guanidine nor a regression in their progress when the drug was stopped. Individual patients, likewise, noted no subjective improvement when they received the drug compared with the placebo. Treatment with guanidine does not enhance recovery from botulism.