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Biomedical subjects

A Solomon

Publications and source records attributed to A Solomon.

At least 19 recordsLinked to original sources
PubMed1992

Horseradish peroxidase labeling of growth cones and axons beyond the site of injury in injured rabbit optic nerve axons growing in their own environment.

Spontaneous growth of injured axons in the mammalian central nervous system is limited. We have previously shown an apparently regenerative growth of injured optic axons in the adult rabbit, achieved by supplying them with soluble substances originating from growing axons, followed by low energy helium-neon laser irradiation. The growing unmyelinated and thinly myelinated axons were embedded in astrocytes, and some were in the process of remyelination by oligodendrocytes. They were shown to have originated from the retinal ganglion cells. The present study further supports evidence relating to the origin and nature of these axons. Light microscopic analysis of these axons labeled with anterogradely transported horseradish peroxidase revealed that many of these axons have varicosities and bear growth cone-like swellings in their tips. These axons traverse the lesion site and extend into the distal stump in a disorganized pattern.

Animals↗
PubMed1992

Patulous rectum extension into the ischiorectal fossa: CT findings.

Protrusion of the rectum with egress into the ischiorectal fossa was present on computed tomography (CT) in three elderly women. CT demonstration of such rectal redundancy in elderly women will avoid unnecessary bowel damage in the case of misguided clinical assessment of rectal pathology.

Aged↗
PubMed1992

Disappearance of astrocytes and invasion of macrophages following crush injury of adult rodent optic nerves: implications for regeneration.

Injury to the mammalian central nervous system results in loss of function because of its inability to regenerate. It has been postulated that some axons in the mammalian central nervous system have the ability to regenerate but fail to do so because of the inhospitable nature of surrounding glial cells. For example, mature oligodendrocytes were shown to inhibit axonal growth, and astrocytes were shown to form scar tissue that is nonsupportive for growth. In the present study we report an additional phenomenon which might explain the failure of axons to elongate across the site of the injury, namely, the absence of astrocytes from the crush site between the glial scar and the distal stump. Astrocytes began to disappear from the injury site as early as 2 days after the injury. After 1 week the site was necrotic and contained very few glial cells and numerous macrophages. Disappearance of glial cells was demonstrated in both rabbit and rat optic nerves by light microscopy, using antibodies directed against glial fibrillary acidic protein, and by transmission electron microscopy. Results are discussed with reference to possible implications of the long-lasting absence of astrocytes from the injury site, especially in view of the differences between the present findings in rodents and our recent observations in fish.

Animals↗
PubMed1992

Use of quantitative polymerase chain reaction to quantitate cytokine messenger RNA molecules.

A quantitative polymerase chain reaction (PCR) using an internal control (Standard) RNA was developed for precise quantitation of human cytokine mRNA. The target mRNA and internal control were simultaneously reverse transcribed and co-amplified using the same set of primers. The amount of specific target mRNA is then quantitated by extrapolating against the standard curve generated with the internal standard. The internal control RNA consisted of linearly connected sequences of the 5' primers of multiple cytokine genes followed by the complementary sequences to their 3' primers in the same order. This structure of the internal standard enables one to use the same internal standard for quantitating multiple cytokine mRNAs. Using this approach, we estimated the induced levels of cytokine mRNA, IL2, IL6, and TNF-alpha to be 2.8 x 10(6), 2.4 x 10(5) and 3.4 x 10(8) molecules per 1.0 microgram total cellular RNA of Jurkat, THP-1 and HL 60 cells, respectively. Comparable values were obtained when quantitation experiments were done on another batch of THP-1 and HL-60 total cellular RNA. The excellent sensitivity and reproducibility makes this approach a valuable one in following changes in cytokine gene expression in wide variety of conditions, both in vivo and in vitro.

Actins↗
PubMed1992

Induction in mice of human light-chain-associated amyloidosis.

Primary (idiopathic) or multiple myeloma-associated amyloidosis is characterized by the deposition in tissue of monoclonal light chains or light-chain fragments (AL amyloidosis). In contrast to other types of amyloidosis, information regarding the pathogenesis of light-chain-related amyloid has heretofore been limited due to the lack of a suitable in vivo model. The authors report the successful experimental induction of human AL amyloid deposits. The repeated injection into mice of Bence Jones proteins obtained from two patients with AL amyloidosis produced the histopathologic lesions characteristic of this disease. Partial dehydration of animals before protein injection resulted in the acceleration of amyloid formation. The human proteins were deposited as amyloid within the mouse renal blood vessel walls and parenchymal tissue, as well as in other organs. The deposits were Congo red-positive, exhibited green birefringence, and had a fibrillar ultrastructure. As evidenced immunohistochemically, the experimentally induced amyloid deposits consisted of the injected human light chains, and in addition, contained mouse amyloid P component (AP); mouse immunoglobulin (Ig) or inflammatory-associated amyloid A protein was not detected. Extraction and characterization of the amyloid deposits found within the mouse kidney revealed the presence of a predominantly intact human light polypeptide chain. Mice injected in identical manner with a non-amyloid-associated Bence Jones protein had no or only rare amyloid deposits. The experimental mouse model provides a means to ascertain the amyloidogenic potential of human monoclonal light chains and to study further the pathogenesis of AL amyloidosis.

Amyloid↗
PubMed1979

Multiple squamous carcinomas and the oesophagus.

Attention is directed to the synchronous and sometimes delayed appearance of squamous carcinoma of the oesophagus with other head and neck squamous carcinomas. The rare occurrence of double carcinoma of the oesophagus is emphasized. Two cases of double carcinoma of the oesophagus occurred in a group of 383 patients who were investigated as part of an epidemiological survey (an incidence of 0,5%). A third case of double carcinoma of the oesophagus is additionally reported.

Carcinoma, Squamous Cell↗
PubMed1979

Contrast computed tomography in the diagnosis of acute cholecystitis.

Computed tomography (CT) has the ability to detect small variations in tissue density. Meglumine diatrizoate was given intravenously to four patients with clinical acute cholecystitis as part of the CT scanning procedure. The enhancement of the thick gallbladder wall, together with an enlarged gallbladder and the presence of stones, confirmed the diagnosis of acute cholecystitis. Our present experience indicates that, after contrast medium administration, CT has a distinct place in the assessment of acute inflammation of the gallbladder.

Acute Disease↗
PubMed1979

Risk of asbestosis in crocidolite and amosite mines in South Africa.

X-rays of all while and mixed-race men employed in crocidolite and amosite mines and mills were read independently by three experienced readers according to the ILO U/C classification. Abnormality was regarded as present if reported by two or more readers. Parenchymal abnormality, defined as the presence of small irregular opacities of profusion 1/0 or greater, was found in 7.3% of the workers. Pleural thickening was found in 4.5% of the workers, costophrenic angle obliteration in 3.2%, and pleural calcification in 1.7%. The prevalences of both pleural and parenchymal abnormality were strongly related to the duration of exposure to asbestos at work. The overall prevalence of abnormality increase from 4.0% in men with exposure for 1 year or less to 47.9% in men with more than 15 years of exposure. After taking into account the effects of age and duration of asbestos exposure, the prevalence of pleural abnormality was not predicted by fiber concentration. However, white men working with amosite tended to develop a higher prevalence of pleural abnormality than did those working with crocidolite. Compared to whites, men of mixed race, who only work with crocidolite, had a high prevalence of pleural abnormality in each exposure duration category. In contrast to pleural abnormality, the prevalence of parenchymal abnormality, after taking into account the effects of age and duration of exposure, was significantly predicted by fiber concentration but not by race or asbestos type. Our results suggest that parenchymal abnormality in workers in South African asbestos mines could be largely prevented by reducing exposure to fibers visible under the light microscope. However, this may not be the case for pleural abnormality.

Adult↗
PubMed1979

Acetylator phenotype in spontaneous SLE and rheumatoid arthritis.

Acetylator phenotype was determined in 22 patients with spontaneous systemic lupus erythematosus and the proportion of 'slow' acetylators compared with that obtained in a group of patients with rheumatoid arthritis and a group of healthy controls. 73% of the SLE group were designated 'slow' compared with 72% of the rheumatoid group and 64% of the control group. These differences were not significant.

Acetylation↗
PubMed1979

cis-Dichlorodiammineplatinum(II) and hexamethylmelamine in the treatment of non-oat cell lung cancer: a pilot study of the Southeastern Cancer Study Group.

Fifty-one patients with metastatic non-oat cell carcinoma of the lung were treated with a combination of cis-dichlorodiammineplatinum(II) and hexamethylmelamine. The overall response rate (all cell types) was 16%. Four of 20 patients with adenocarcinoma had a partial response and an additional five patients classified as having stable disease had tumor regression less than 50%. The median survival of responders and of those with stable disease (all types) was 8 and 7 months respectively, significantly longer than the median survival of patients who progressed (median survival, 2 months [P less than 0.05]). The major dose-limiting toxicity was nausea and vomiting in over half of the patients; hematologic toxicity and peripheral neuropathy were the other adverse effects of the combination.

Adenocarcinoma↗
PubMed1979

Computed tomography in pulmonary sarcoidosis.

A group of 34 proven cases of pulmonary sarcoidosis was investigated by computed tomography (CT) to determine whether CT provided any information beyond that obtained from conventional chest films. Computed tomography disclosed a surprisingly high prevalence of minor pleural changes in sarcoidosis, including two patients with small pleural effusions. Unsuspected bullae and isolated "granulomatous" nodules were additionally demonstrated. Increases in lung density and alterations in gravity dependent vascular perfusion were assessed; these may reflect alterations in the vascular bed, and the increased density is possibly due to diffuse invasion of the lung not recognizable by conventional chest X-ray films. Tracheal compression was noted in one case and vertebral densities in three. Prominence of "small air spaces" was recorded in four patients; the nature of the pathology responsible for this finding is at present speculative. While not replacing conventional chest radiography, CT does make a definite contribution to the assessment of pulmonary sarcoidosis.

Adolescent↗