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Biomedical subjects

W J Logan

Publications and source records attributed to W J Logan.

10 recordsLinked to original sources
PubMed1992

Somatosensory evoked potentials and nerve conduction studies in patients with Guillain-Barré syndrome.

Somatosensory evoked potentials, F-waves, and nerve conduction studies (NCS) were performed to determine their usefulness in detecting electrophysiologic abnormalities in 23 children in the acute stage of Guillain-Barré syndrome. The studies were performed on average 8.3 days after the onset of neurological symptoms, before the period of maximal weakness. All patients had at least one abnormal test. Somatosensory evoked potentials (SEP) showed most abnormalities: 91% abnormal recordings with posterior tibial nerve (PTN) stimulation and 68% with median nerve (MN) stimulation. The nerve conduction velocities were abnormal in 76% and 67% with PTN and MN stimulation, respectively. The F-waves were abnormal in 66% (PTN) and 56% (MN). The SEP studies were helpful in detecting proximal and central conduction abnormalities in 26% of patients, and they were more sensitive in detecting an abnormality when compared with F-wave recordings. Furthermore, in one patient with normal NCS and F-waves the prolonged lumbar potential-P35 conduction time of the PTN-SEP was the only abnormality found. SEP can detect an abnormality and thus support the clinical diagnosis of Guillain-Barré syndrome in the acute stage when the results of more conventional tests are inconclusive.

Adolescent↗
PubMed1979

Erythrosin B inhibition of neurotransmitter accumulation by rat brain homogenate.

A mixture of seven food dyes inhibited the accumulation of eight neurotransmitters or neurotransmitter precursors by rat brain homogenate. At a low concentration (1 microgram per milliliter), erythrosin B (FD&C red 3) was the only dye that inhibited dopamine accumulation. Erythrosin also was effective in decreasing the accumulation of all the other transmitter substances, suggesting that the inhibition is nonspecific and probably secondary to general membrane alteration.

Animals↗
PubMed1979

Central nervous system maturation in the stressed premature.

The developmental sequence of sleep cycles has been found to be a useful index of central nervous system maturation in premature infants. To determine the effects of severe reversible stress on the maturation of sleep cycles, 6- to 8-hour sleep studies were done on 10 premature infants with severe hyaline membrane disease (HMD) and 10 healthy premature babies. The studies were done in the neonatal intensive care unit and included patients from 30 weeks' gestation to term and in all stages of the disease. Prior studies were confirmed showing that percentage of quiet sleep increases, transitional sleep changes little, and active sleep decreases from 30 weeks' gestation to term. In infants with severe HMD, the percentage of quiet sleep was less and active sleep higher than in unstressed infants of similar age who acted as controls. Once the infants recovered from HMD, sleep patterns became similar to those found in the control group. These data suggest that when respiratory distress occurs in the premature infant, there is a transient delay in central nervous system maturation as measured by sleep cycle analysis.

Brain↗
PubMed1979

Two spontaneous BALB/c lymphomas synthesize IgM: monomers and half molecules are isolated and characterized whereas another molecule resembles IgD.

Spontaneous lymphomas of BALB/c mice, both in vivo tumors and cell lines established in long term tissue cultures, were investigated for their ability to synthesize IgM by using radiolabeled amino acid precursors. Immunoglobulins manufactured by lymphomas K46 and L10A had the m.w. of monomeric IgM and IgM half molecule. Both of these molecules could be immunoprecipitated with class-specific anti-IgM but not anti-IgA or anti-IgG. When precipitated with polyvalent anti-Ig L10A synthesized monomeric immunoglobulins that migrated as two peaks in contrast to their single counterpart precipitated with anti-IgM. The second peak migrated in the region expected for IgD. Monomer and half molecules were composed of similar ratios of mu-chains to light chains linked by disulfide bonds. The mu2L2 monomer of these B cell lines migrated slightly slower in SDS PAGE than a mu2L2 secreted by a myeloma. Thus, these lymphomas synthesize immunoglobulins with the chemical and antigenic characteristics typical of monomeric membrane-attached IgM and IgM half molecules, plus a molecule resembling IgD on L10A only. Lymphoma assembly of monomeric IgM may follow the same initial biosynthetic sequence as myeloma assembly.

Animals↗
PubMed1978

Clear-cell sarcoma of tendons and aponeuroses.

The natural history and histologic characteristics of a rare malignant neoplasm of tendons and aponeuroses are described, and a case is presented which originated in the right foot of a 19-year-old Caucasian woman who succumbed to the disease after 4 years. This case represents the first known example of metastasis to the oral cavity of this particular neoplasm.

Adult↗
PubMedDate not supplied

Amino acid transport by a muscle cell line.

An established rat muscle cell culture, L-6, was employed for the evaluation of muscle amino acid transport. The initial influx of 16 radiolabeled amino acids into these cells was determined, and an overall uptake profile was constructed. L-6 cells accumulate amino acids progressively with time by saturable, temperature-dependent processes. As found in other preparations, several amino acids have sodium-dependent uptake systems. There is a wide range in the rate of transport of the different amino acids. The overall profile of uptake is fairly reproducible and may be characteristic of muscle tissue; it does not resemble that previously found in other cell types. The profile of amino acid uptake into these cells compares favorably with the pattern of amino acid transfer from the bloodstream to muscle found in intact rats. It is concluded that muscle cell transport is basically similar to that of other cell types. L-6 muscle cells have an amino acid uptake profile which resembles that of intact muscle; they should thus prove useful in the further delineation of muscle amino acid transport mechanisms.

Amino Acids↗