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Biomedical subjects

A Solomon

Publications and source records attributed to A Solomon.

At least 235 records · Page 13Linked to original sources

A new transorbital surgical approach to the rabbit's optic nerve.

This work describes a surgical approach which establishes the rabbit's visual system as an experimental model for studying CNS regeneration. Using this model, the optic nerve, its cell bodies, and the axons, are easily accessible through an orbital approach, without the need for craniotomy and brain retraction. This surgical approach allows transplantation and 'wrap around' implantations of nerve segments from xenogeneic and syngeneic systems and diffusible substances derived from them, respectively. Furthermore, it enables studies aimed at determining deficiencies in mammalian CNS and investigating methods of augmentating mammalian CNS regeneration.

Animals↗

Human lambda light-chain constant region gene CMor lambda: the primary structure of lambda VI Bence Jones protein Mor.

Serologic, structural, and genetic analyses have shown that the constant (C) region of human kappa light chains is encoded by a single gene, whereas that of lambda chains is encoded by multiple genes. We have determined the complete C region amino acid sequence of two monoclonal lambda VI light chains, Bence Jones proteins Sut and Mor. The C region of lambda chains Sut and Mor consists of 105 residues, as is characteristic for human lambda light chains, of which 102 are identical in sequence. Protein Sut has the C region sequence associated with the C lambda isotype Mcg-, Kern-, Oz+ and represents a product of the C lambda 3 (Kern-, Oz+) gene. Protein Mor has a C region sequence associated with Mcg-, Kern-, and Oz- proteins but differs from protein Sut by the presence of three amino acid interchanges at positions 168, 176, and 194. These substitutions distinguish protein Mor from lambda chains encoded by the C lambda 1 (Mcg+), C lambda 2 (Kern-, Oz-), and C lambda 3 (Kern-, Oz+) genes and provide further evidence for polymorphism of the human C lambda genome. The gene encoding the C region sequence of lambda chain Mor is designated CMor lambda.

Amino Acid Sequence↗

Alterations in mRNA translation products associated with regenerative responses in the retina.

Translation products of mRNA from retinas of goldfish optic nerve (representing a regenerative CNS) and adult rabbit optic nerve (representing a nonregenerative CNS which can be induced to express regenerative characteristics) were examined by one- and two-dimensional gel electrophoresis. Translation products from retinas of the regenerating goldfish optic nerve included polypeptides barely detectable in the translation products of mRNA derived from retinas of uninjured controls. Some of these polypeptides, of apparent molecular weights 24-28, 43-49, 60, and 65 kilodaltons can be considered as growth-associated polypeptides described in other regenerative and developing systems. The induction of regeneration-associated characteristics in the injured adult rabbit optic nerve, "implanted" with diffusible substances from nonneuronal cells of regenerative or growing nerve, is reflected by changes in the mRNA translation products of the retina. Among such translation products are those of the following molecular weights: 16-18, 28, 32-35, 43-47, and 56-60 kilodaltons, and some higher-molecular-weight species.

Animals↗

Costovertebral anomalies in osteogenesis imperfecta.

Study of 16 patients with Type III osteogenesis imperfecta showed marked elongation of the pedicles of the vertebrae in all cases, a deformity which was not seen in other types of the disease. Posterior rib angulation was also noted in Type III disease. These features have proved useful in suggesting the diagnosis of osteogenesis imperfecta even before long bones have fractured and in categorizing patients with osteogenesis imperfecta into the correct type for prognostic purposes.

Biomechanical Phenomena↗

Motivation and productivity in the radiology department.

The successful motivation of employees is often seen as a way to reach a maximum level of productivity. The authors attempt to identify the components of personal motivation, define motivation theories, and explore motivation strategies that can be utilized in a radiology department. The purpose is to discover the relationship between motivation and increased productivity. The authors also examine productivity measurement systems currently being used in radiology departments.

Efficiency↗

Activity of rheumatoid factors of different molecular sizes: comparison of autologous monomeric and polymeric monoclonal IgA rheumatoid factors.

Differences in rheumatoid factor (RF) activity among the molecular species of IgA were investigated with the use of monomeric and polymeric monoclonal IgA RF paraprotein from the serum of a patient (PS) with idiopathic hyperviscosity syndrome. After fractionation by gel chromatography in acidic buffer, RF activity as determined by latex fixation and solid-phase radioimmunoassay (RIA) specific for IgA RF was confined to the high m.w. (greater than 7S) fractions. However, after adsorption into polystyrene wells, fractions containing monomeric (7S) IgA, as well as those containing polymeric IgA, bound 125I-labeled heat-aggregated human IgG. These observations were confirmed after further purification of the IgA fractions by passage through a protein A-Sepharose CL-4B column followed by precipitation of the IgA proteins with ammonium sulfate at 50% saturation. After "cross-linkage" by a hybridoma anti-human alpha-chain antibody, the activity of the monomeric IgA preparation in the IgA RF RIA approached that of the polymeric IgA preparation. Gel filtration studies verified that this activity was not due to contamination by polymeric IgA RF. Further, classic RF specificity was confirmed for both the monomeric and polymeric IgA RF by reaction with human Fc-coated but not Fab-coated wells. A control monomeric IgA myeloma protein and normal serum IgA did not react in the RF RIA when analyzed in the presence or absence of the hybridoma anti-alpha-chain antibody. Moreover, the activity of the polymeric IgA RF preparation from patient PS in the RIA was minimally influenced by the hybridoma antibody. These results indicate that IgA RF can coexist in both polymeric and monomeric forms, demonstrate that monomeric IgA RF may escape detection by previously described RIA techniques, and suggest an approach for its detection.

Animals↗

Hemoptysis in sarcoidosis.

We describe 4 previously healthy patients with non-cavitated pulmonary sarcoidosis, whose presenting symptom was hemoptysis. Despite the presence of pulmonary involvement in about 90% of patients with sarcoidosis, hemoptysis as the presenting symptom is very rare and was described previously, to our knowledge, in only 5 patients.

Adult↗

Pulmonary sarcoidosis presenting with unusual roentgenographic manifestations.

Chest roentgenograms of 85 Jewish patients with biopsy-proven pulmonary sarcoidosis were reviewed. In 25 cases (29%), the initial chest roentgenogram showed one of the following unusual manifestations: large pulmonary nodules in 11, an acinar pattern in 10, right hilar lymphadenopathy in 3 and a large pericardial effusion in one patient. Diagnostic biopsy specimens were obtained by an open lung biopsy in 13 patients, by anterior mediastinoscopy in 4, by transbronchial lung biopsy in 3, by skin biopsy in 3 and by liver and splenic tissue examination in 2 patients. Complete roentgenographic resolution occurred only in 4 out of 20 patients who were followed for more than two years (20%), but the majority of them (83% - 15 out of 18 symptomatic patients), improved clinically irrespective of corticosteroid administration. One patient died in the course of follow-up from a cause attributed to sarcoidosis (5% - one out of the 20 patients who were followed for more than two years).

Adrenal Cortex Hormones↗

Sequence similarities among kappa IIIb chains of monoclonal human IgM kappa autoantibodies.

Light chains of the serologically and chemically defined V region sub-subgroup kappa IIIb are preferentially associated with several types of human IgM kappa (monoclonal) autoantibodies and are remarkably homologous in primary structure, as evidenced by partial amino acid sequence data. To establish the extent of homology among such proteins, we have determined the complete variable region (V) sequence of the light chains of four monoclonal IgM kappa autoantibodies, of which two (GAR and GOT) are rheumatoid factors (RFs), the third (SON) has anti-apo beta lipoprotein specificity, and the fourth (PIE) binds specifically to intermediate filaments. The region encoded by the V kappa segment gene (positions 1-95) in all four light (L) chains is virtually identical in sequence, differing by only one residue in the FR3 of protein SON and in the first CDR of protein GOT. Further, the CDR3 of kappa chain SON contains an additional residue (prolyl) located at the carboxyl-terminus of the V segment. The region encoded by the J gene (positions 96-108) is identical after position 96 for the two RFs GAR and GOT (J kappa 2), but different in proteins SON (J kappa 4) and PIE (J kappa 1). The amino acid residue at position 96, located in CDR3 at the site of combinatoriaL joining of the V kappa and J kappa gene segments and involved as a contacting residue in the hapten binding site, is different in all four light chains. These results demonstrate the extensive homology in sequence among light chains of IgM kappa autoantibodies and indicate that a particular V kappa germ line gene, kappa IIIb, is expressed as a phylogenetic response to certain self antigens or as part of a selection process by which these autoimmune responses are regulated.

Amino Acid Sequence↗

Multiple myeloma: early vertebral involvement assessed by computerised tomography.

Routine radiography is the primary method of evaluating skeletal involvement by myeloma. In contrast, radio-isotope bone scans have a low sensitivity, the medium being taken up only at sites of active or reactive bone formation. A group of six patients with multiple myeloma, established by clinical and laboratory findings, had no radiological evidence of bone involvement. Computerised tomography (CT) of the vertebral column revealed limited lytic lesions of the vertebral spongiosa in four of the patients. The three-dimensional ability of CT to "look inside" the vertebrae permits early detection of spinal lesions associated with myeloma. As a supplementary investigation, three additional patients, with frank radiographic evidence of extensive myelomatous bone lesions were examined similarly by CT. In these patients the technique showed involvement of the vertebral column to be more widespread and to affect many more vertebral bodies than had been evident in orthodox radiological examinations. CT permits earlier demonstration of early vertebral lesions and is more accurate in the delineation of the extent of vertebral involvement than conventional radiography.

Aged↗

Importance of the falciform ligament, ligamentum teres and splenic hilus in the spread of malignancy as demonstrated by computed tomography.

Computed tomographic detection of significantly large (greater than 1.5 cm) transcoelomic secondary malignant serosal deposits is discussed. Attention is drawn to the importance of the falciform ligament, ligamentum teres, and splenic hilus as sites of secondary deposits. An anatomical explanation is presented for the detection of these findings on computed tomography.

Abdomen↗

The syndromes of pancreatic pseudocysts and fluid collections.

The clinical and radiologic spectrum of pseudocysts associated with alcohol-induced pancreatitis is wide and variable. Several illustrative cases which delineate the diversity of syndromes that occur with pseudocysts are presented. A classification is proposed to facilitate a more coherent approach to the concept of pseudocysts and is based on the clinical presentation. Thus, in acute pancreatitis duct disruption and enzyme activation may result in intrapancreatic or extrapancreatic fluid collections. In calcifying chronic pancreatitis duct obstruction may result in pseudocysts of the head, body, or tail of the pancreas, which can enlarge and penetrate into extrapancreatic sites. This subdivision will assist in elucidating the natural history of pseudocysts and pancreatic fluid collections. Furthermore, it may establish new guidelines for diagnosis and therapy.

Adult↗

Substances originating from the optic nerve of neonatal rabbit induce regeneration-associated response in the injured optic nerve of adult rabbit.

We have recently shown that cell bodies of an injured optic nerve of adult rabbit can be induced to express regeneration-associated response by external signals derived from nonneuronal cells of regenerating nerves of lower vertebrates. In this study it is shown that even substances derived from a nonregenerating mammalian system also can trigger such a regenerative response. Thus, substances derived from intact nerves of neonatal rabbits and of adult rabbits, to a lesser extent, were active in triggering a regeneration-associated response, whereas substances derived from injured nerves of adult rabbit were not. However, if subsequent to the injury the nerve was implanted with silicone tube containing medium conditioned by neonatal optic nerves, the substances derived from the implanted injured nerve were active. Thus, it appears that the ability of a periaxonal environment to provide triggering substances correlates with axonal growth. Therefore, we named these substances "growth-associated triggering factors" (GATFs). It is suggested that mammalian cells are unable to express a regenerative response after an injury due to the failure of their nonneuronal cells to produce regeneration-triggering substances. This disability may be circumvented by an appropriate implantation procedure.

Aging↗