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Biomedical subjects

M B Nelson

Publications and source records attributed to M B Nelson.

28 records · Page 2Linked to original sources
PubMed1978

Histological patterns of muscle in infants with developmental brain abnormalities.

The histology of muscle obtained from 23 hypotonic infants without neuromuscular disease is presented. Long-term follow-up neurological examinations were carried out to determine the site of the lesion. 18 cases have strong evidence of cerebral dysfunction, 12 of whom have histologial abnormalities of fiber-type distribution and diameter. Of the remaining five patients without obvious cerebral abnormality, four also had histological changes, but individual circumstances partially explain the cause of the abnormal histological patterns in these four. No single histological abnormality could be identified, but the results indicate that histological abnormalities of muscle in hypotonic infants without clinical or microscopic evidence of neuromuscular disease may be useful in predicting a cerebral cause for the hypotonia.

Brain↗
PubMed1977

Congenital fiber type disproportion in identical twins.

Eighteen-month-old identical twins with the muscle histological characteristics of congenital fiber type disproportion are reported. The fiber typing system of pH-dependent adenosine triphosphatase was used to analyze the size and percentage of type 1, 2A, and 2B fibers in muscle tissue obtained by needle biopsy. Both twins had significantly larger type 2 than type 1 fibers, with 2B fibers representing the largest type. One patient also had type 1 predominance at the expense of a reduction in 2B (2B deficiency). The probands as well as other family members had transient delayed motor development, macrocephaly, and normal intelligence. A biopsy obtained from 1 of these family members failed to demonstrate a similar histological abnormality. The disorder is nonprogressive in this family, as evidenced by minimal disability in the older members and gradual improvement in the probands.

Biopsy, Needle↗
PubMed1977

Brain and spinal cord lesions in the newborn rat.

Previous studies involving the induction of central nervous system lesions in animals have required complex, expensive equipment including sterotaxis and an operating microscope. This study describes a technique for producing telencephalic (forebrain) lesions in the developing rat by the use of copper wire. In addition, a nonvisual method of producing spinal cord transections in the young rat is discussed. Both techniques have a high succes rate and minimal mortality.

Animals↗
PubMed1976

Developmental patterns of rat muscle histochemistry.

A developmental progression of histochemical fiber typing is demonstrated in normal rat soleus muscle. By utilizing the acid lability of ATPase, the type II fibres are subdivided into type IIA, IIB and IIC. No IIB fibers are present in the newborn or adult rat soleus. In the 1-day-old animal 90% of the fibers can be differentiated into type I and II with all of the type II's demonstrating IIC characteristics. Only type I and IIC fibers are present until 18 days, when poorly differentiated IIA fibers first appear and gradually become the predominant type II fiber at the expense of IIC's. Further analysis documents the sequence of disappearance of myotubues from up to 80% of all fibers in the 1-day-old to less than 1% between 15 and 18 days. An analysis of the progression of fiber size according to type is presented.

Adenosine Triphosphatases↗
PubMed1975

Needle biopsies of muscle in infants for diagnosis and research.

The results of needle biopsies of muscle in 14 infants (age-range four months to 3 years 3 months) with marked hypotonia are presented. In adults, needle biopsies of muscle have been used to aid in the diagnosis of neuromuscular disorders, with considerable success. The simplicity of the method and the high quality of the samples obtained in the present study suggest that further evaluation of the technique in infants and small children is warranted, and that needle biopsy may in future take precedence over the more commonly used open technique.

Biopsy, Needle↗
PubMedDate not supplied

Tumor cells express FcgammaRI which contributes to tumor cell growth and a metastatic phenotype.

High levels of circulating immune complexes containing tumor-associated antigens are associated with a poor prognosis for individuals with cancer. The ability of B cells, previously exposed to tumor-associated antigens, to promote both in vitro and in vivo tumor growth formed the rationale to evaluate the mechanism by which immune complexes may promote tumor growth. In elucidating this mechanism, FcgammaRI expression by tumor cells was characterized by flow cytometry, polymerase chain reaction, and sequence analysis. Immune complexes containing shed tumor antigen and anti-shed tumor antigen Ab cross-linked FcgammaRI-expressing tumor cells, which resulted in an induction of tumor cell proliferation and of shed tumor antigen production. Use of selective tyrosine kinase inhibitors demonstrated that tumor cell proliferation induced by immune complex cross-linking of FcgammaRI is dependent on the tyrosine kinase signal transduction pathway. A selective inhibitor of phosphatidylinositol-3 kinase also inhibited this induction of tumor cell proliferation. These findings support a role for immune complexes and FcgammaRI expression by tumor cells in augmentation of tumor growth and a metastatic phenotype.

Animals↗
PubMedDate not supplied

Studies on P6, an important outer-membrane protein antigen of Haemophilus influenzae.

P6, a 16,600-dalton outer-membrane protein of Haemophilus influenzae, possesses many characteristics desired of a vaccine candidate. The protein is present in all strains of H. influenzae tested by analyses of outer-membrane protein profiles and with a monoclonal antibody. P6 is surface-exposed, as demonstrated by immunostaining techniques. Studies using monoclonal and polyclonal antisera indicate that P6 is a highly conserved antigen on the outer membrane of H. influenzae. Finally, experiments using affinity chromatography and normal human serum establish that P6 is a target of human bactericidal antibodies. The gene encoding P6 has been isolated and cloned into Escherichia coli, an accomplishment that will facilitate molecular analysis of the role of P6 in human immunity to H. influenzae.

Antigens, Bacterial↗