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Biomedical subjects

L Paul

Publications and source records attributed to L Paul.

At least 19 recordsLinked to original sources
PubMed1991

Amyloid filaments in inclusion body myositis. Novel findings provide insight into nature of filaments.

Inclusion body myositis (IBM) represents a serious debilitating disease of muscle without identifiable cause or treatment. Muscle biopsy specimens have characteristic rimmed vacuoles, varying degrees of inflammation, and, most importantly, cytoplasmic and intranuclear filamentous inclusions of unknown composition. Fresh-frozen sections of muscle biopsy specimens from 24 IBM cases were stained with Congo red dye (pH, 10.5 to 11.0). Control biopsy specimens included polymyositis, dermatomyositis, hereditary vacuolar myopathies of unknown cause, acid maltase deficiency, distal myopathy, oculopharyngeal dystrophy, and chloroquine myopathy. Sections were also immunostained with antibody to transthyretin, human P component, and immunoglobulin light chains. In the vacuolated fibers in IBM, amyloidogenic green-birefringent deposits were seen. Some deposits were delicate and wispy appearing, and others were plaque-like. The size of deposits varied, measuring 1 x 2 to 8 microns, and rarely up to 20 microns in length. The number of amyloid-positive fibers correlated with the number of vacuolated fibers. Similar deposits were seen in one case of distal myopathy and one hereditary vacuolar myopathy. Other control cases were negative for amyloid deposits. Antibody staining for known amyloidogenic proteins was negative. This study demonstrates that the filaments in IBM share properties with amyloid proteins. The location implies that this amyloid material is formed intracellularly, rather than having a systemic derivation. The association of amyloid deposits with autophagic vacuoles in IBM raises the likely possibility that the filaments represent a modification of a normal protein within an acidic degradative vacuolar compartment. An alternative possibility, considering the shared properties of IBM filaments and prions (which include size and amyloidogenic properties), is that IBM represents a human prion disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

C4-mediated inhibition of immune precipitation and differences in inhibitory action of genetic variants, C4A3 and C4B1.

The inhibition of immune precipitation is mediated by the classical complement pathway. We report here that the rate of precipitate formation depends on the genetic form of human C4 present during immune precipitation. C4A3 is more effective than C4B1 in its capacity to inhibit the rate of immune precipitate formation in serum and in serum-free reaction mixtures containing C1 and C4. Immune precipitates form within seconds after antigen is mixed with antibody, and the activation of the classical pathway is known to occur within seconds after C1 binds to antibody molecules. The covalent deposition of C4b on immune complexes is an essential step in the inhibition of immune precipitate formation, and if any of the reactions that lead to covalent C4b deposition become limiting, the rate of immune precipitation could exceed the complement system's inhibitory capacity. Hence, the inhibition of this rate may be an important function underlying the complement-mediated processing of immune complexes, and a decreased ability of the complement system to mediate this process in the presence of C4B1, in contrast to C4A3, could explain, at least in part, the association between the C4A-null phenotype and autoimmune diseases such as systemic lupus erythematosus.

Animals↗
PubMed1988

Premenstrual changes. Impaired hormonal homeostasis.

Premenstrual changes (PMCs) in mood and behavior are very prevalent. Nonetheless, their pathophysiology is still obscure and no proven treatment is yet available. Evaluation of the plethora of available data leads to the suggestion that PMCs may result from a temporary impairment of homeostasis among a multitude of systems. This impairment is triggered by a differential pace and magnitude of change-over-time in levels of several hormones and other substances during the luteal phase.

Dietary Carbohydrates↗
PubMed1988

Premenstrual changes. Impaired hormonal homeostasis.

Premenstrual changes (PMCs) in mood and behavior are very prevalent. Nonetheless, their pathophysiology is still obscure and no proven treatment is yet available. Evaluation of the plethora of available data leads to the suggestion that PMCs may result from a temporary impairment of homeostasis among a multitude of systems. This impairment is triggered by a differential pace and magnitude of change-over-time in levels of several hormones and other substances during the luteal phase.

Endorphins↗
PubMed1986

Evaluation of "at risk" alpha 1-antitrypsin genotype SZ with synthetic oligonucleotide gene probes.

Alpha 1-antitrypsin (alpha 1AT), a 52,000-mol-wt serum glycoprotein produced by hepatocytes and mononuclear phagocytes, functions as the major inhibitor of neutrophil elastase. The alpha 1AT haplotype S is associated with childhood liver disease and/or adult emphysema when inherited with the Z haplotype to give the phenotype SZ. To accurately identify the SZ phenotype at the level of genomic DNA, four 32P-labeled 19-mer synthetic oligonucleotide probes were prepared; two to identify the M and S difference in exon III, and two to identify the M and Z difference in exon V. These probes were hybridized with various cloned DNAs and genomic DNAs cut with the restriction endonucleases BgII and EcoRI; the genomic DNAs represented all six possible phenotype combinations of the M, S, and Z haplotypes (MM, MS, MZ, SS, ZZ, and SZ). Using the four probes to evaluate 42 samples of genomic DNA, the "at risk" SZ and ZZ phenotypes were correctly identified in all cases, as were the "not at risk" phenotypes SS, MS, MM, and MZ, demonstrating that both exon III and exon V directed probes are necessary to properly identify all of the major "at risk" alpha 1AT genes. However, when used to evaluate a very rare family carrying a null allele, these four oligonucleotide probes misidentified the "at risk" null-null and S null phenotypes as "not at risk" MM and SM combinations. These observations indicate that oligonucleotide gene probes yielded reliable and accurate assessment of "at risk" alpha 1AT genotypes in almost all situations, but in the context of prenatal diagnosis and genetic counseling this approach must be used with caution and in combination with family studies so as not to misidentify rare genotypes that may be associated with a risk for disease.

Base Sequence↗
PubMed1985

On the apparent nonadhesive nature of axospinous dendritic synapses.

Synaptosome preparations are rich in synaptic sacs with adherent fragments of postsynaptic membrane and it has been hypothesized that pre- and postsynaptic membranes are strongly adherent across the synaptic cleft. Scanning electron microscopy of tissue specimens subject to preliminary tearing reveals synaptic terminals on neuronal cell bodies and dendrites as well as pits in the plasma membrane from which other terminals have been avulsed. However, neither synaptic terminals nor membrane pits were seen on dendrite spines in our material. These observations support the notion of adhesion between pre- and postsynaptic membranes but suggest an absence of such adhesiveness between the elements of the axospinous synapse, fitting well with recent conceptions about spine lability and the rapid making and breaking of axospinous synapses.

Adhesiveness↗