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Biomedical subjects

J B Nelson

Publications and source records attributed to J B Nelson.

65 records · Page 4Linked to original sources
PubMed1967

Experimental transmission of a murine microsporidian in Swiss mice.

The production of ascitic fluid and splenomegaly on intraperitoneal injection in weanlings was used as a test for microsporidia after introduction by other routes and in other loci. Oral and cerebral administration was followed only by enlarged spleens which reproduced the ascitic response on passage. Microsporidia were demonstrable by phase microscopy in all fluids. Positive findings were also obtained with liver, kidney, brain, lungs, blood, and urine. Intramuscular and intranasal injection were occasionally followed by ascites, but splenomegaly again predominated. The results of contact experiments indicated that the organisms were not readily communicable either in weanlings or nurslings. Relation of the microsporidian to Encephalitozoon cuniculi (Nosema cuniculi Lainson et al.) is discussed.

Animals↗
PubMed1965

Phase-contrast and electron microscopy of murine strains of Mycoplasma.

Nelson, John B. (The Rockefeller University, New York, N.Y.), and Michael J. Lyons. Phase-contrast and electron microscopy of murine strains of Mycoplasma. J. Bacteriol. 90:1750-1763. 1965.-Two strains of Mycoplasma pulmonis (associated with infectious catarrh) on examination in fluid culture (20% horse serum-bouillon) by phase microscopy were highly pleomorphic, with many bacilliform elements and fewer coccoid ones. Motility, characterized by gliding of rods and spinning of spherical forms, was observed through the 9th subculture of one strain and the 15th of the second. Motile elements were not seen in later transfers and pleomorphism was reduced. One strain of M. neurolyticum (associated with conjunctivitis and encephalitis) was much less pleomorphic and showed neither bacilliform elements nor motility at any time. When examined by negative-contrast electron microscopy, organisms of this strain were found to have an average diameter of 0.7 mu and to possess a concentrated peripheral layer of cytoplasm and a central mass which may represent the cells' nuclear equivalent. The latter feature was not prominent in spherical forms of M. pulmonis. These cells, when observed after 48 hr of culture, showed evidence of the generation of new progeny cells in their central area. The filamentous or bacilliform cells of M. pulmonis were frequently serpentine in appearance, 2.0 to 3.0 mu in length and 80 to 250 mmu in width. They appeared to generate new cells from terminal buds from which outpouchings initially developed. Older cells, in the stationary phase, showed evidence of undergoing multipolar germination. Microtubules, about 60 mmu wide, were found in association with most filamentous cells from 48-hr cultures; fragments of membrane, studded with closely packed ribosomelike particles, were also found. There was no evidence of flagella or any specialized structure that could account for the observed motility of the organisms.

Animals↗
PubMedDate not supplied

Extra-hippocampal projections of CCK neurons of the hippocampus and subiculum.

A population of neurons in the hippocampus and subiculum contains cholecystokinin (CCK). Following transection of the dorsal fornix, a major afferent pathway of the hippocampus and associated structures. CCK levels were reduced in the septum and hypothalamus. A microdissection analysis indicated that the loss of CCK occurred in nuclei receiving direct projections from the hippocampus and subiculum, suggesting that CCK-containing neurons in the hippocampus and subiculum project to extrahippocampal regions.

Afferent Pathways↗
PubMedDate not supplied

The treatment of prostate cancer: an overview of current options.

PURPOSE: The purpose of this report is to discuss the current treatment options available to the patient with prostate cancer in all stages of the disease. OVERVIEW: With the exception of skin cancer, prostate cancer is the most common cancer in men in the United States. Most patients in the current era will present with organ-confined disease, amenable to curative treatment. Treatment for organ-confined disease includes watchful waiting, radical prostatectomy, radiation therapy, and cryosurgery in selective cases. Hormone therapy is the cornerstone of treatment of patients with advanced prostate cancer. There is no curative treatment for hormone-refractory prostate cancer. CLINICAL IMPLICATIONS: The availability of several therapeutic options for localized prostate cancer warrants careful consideration when planning treatment with curative intent. Patients need to be active participants in decision making, and they must be aware of the benefits and possible complications of the different types of treatment. Patients with advanced prostate cancer need to be aware that hormone treatment will provide temporization and palliation in the majority of cases. Hormone-resistant prostate cancer is refractory to most forms of conventional and experimental therapy.

Androgen Antagonists↗
PubMedDate not supplied

Prostate cancer metastasis-suppressor genes: a current perspective.

Prostate cancers account for 43% of all cancers diagnosed in American men. It is estimated that in 1996, 317,000 new cases of prostate cancer were diagnosed and 41,000 men died of the disease. The challenge of treating prostate cancer lies in accurately distinguishing those histologically-localized cancers which will complete metastatic progression from those that will remain indolent. At this time, we lack appropriate histological markers to make such distinctions, therefore, it is often difficult to accurately predict the clinical course of an individual patient's disease. There is growing evidence that a critical event in the progression of a tumor cell from a non-metastatic to metastatic phenotype is the loss of function of metastasis-suppressor genes. These genes specifically suppress the ability of a cell to metastasize. Work from several groups has demonstrated that human chromosomes 8, 10, 11 and 17 encode prostate cancer metastasis suppressor activities. As a result of these efforts the first prostate cancer metastasis-suppressor gene, KAI1, was identified and mapped to the p11-2 region of chromosome 11. In subsequent studies, an additional gene encoded by the same region, CD44 was also determined to have metastasis-suppressor activity. Recent studies have shown a correlation between decreased expression of KAI1 and CD44 and an increased malignant potential of prostate cancers. It is anticipated that the identification of other metastasis suppressor genes may allow for the development of diagnostic markers useful in the clinical substaging of individual tumors. This manuscript is intended to present our perspective on the importance of these genes in the understanding of prostate cancer progression. More importantly, we present new findings from our laboratory's effort to identify the metastasis-suppressor genes encoded by human chromosome 17. Specifically we report the strategy currently being used to evaluate a series of candidate genes and the approach being utilized to pinpoint the metastasis-suppressor region on human chromosome 17.

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