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Biomedical subjects

A Newman

Publications and source records attributed to A Newman.

At least 91 records · Page 5Linked to original sources
PubMed1987

Intramedullary spinal cord metastasis in Hodgkin's disease. Rapid diagnosis and treatment resulting in neurologic recovery.

Intramedullary spinal cord metastases are uncommon in Hodgkin's disease and have a poor prognosis. This prognosis reflects the refractory or widely disseminated status of the disease at the time of development of neurological symptoms and difficulties in diagnosis. Computerized tomography and magnetic resonance imaging have enabled more rapid and specific diagnosis of spinal cord diseases. The authors report a patient who presented with Brown-Sequard syndrome due to intramedullary spinal cord infiltration from Hodgkin's disease. This patient was diagnosed promptly and with rapid initiation of radiation and chemotherapy, she has had neurologic recovery.

Adult↗
PubMed1987

Regeneration of the eighth cranial nerve. II. Physiologic verification in the bullfrog.

Two experiments were performed to document the functional capacity of the regenerated eighth cranial nerve. In experiment 1, the eighth cranial nerve was sectioned preganglionically and allowed to regenerate in a group of bullfrogs with normal contralateral eighth nerve and labyrinth. Posture and reflex to lateral tilt were measured preoperatively and postoperatively for a minimum of 3 months. Similar measures were performed in a second group of bullfrogs in which the eighth nerve had been destroyed by ganglionectomy and in a third with peripheral labyrinthectomies. In experiment 2, the eighth nerve was sectioned and allowed to regenerate in bullfrogs in which the contralateral nerve had previously been destroyed. Posture and reflex to lateral tilt were measured as in experiment 1. Similar measures were performed in a group of bullfrogs that had undergone bilateral nerve destruction. Regeneration of the eighth cranial nerve in bullfrogs in both experiments was documented histologically by labeling the regenerated fibers with horseradish peroxidase (HRP). In both experiments, posture recovered completely only in the bullfrogs in which the eighth cranial nerve was allowed to regenerate. Reflex to lateral tilt recovered more rapidly in the bullfrogs with regenerated nerves than in any of the other bullfrogs.

Animals↗
PubMed1987

Eikenella corrodens infection of the hand--a case report and literature review.

Eikenella corrodens, a gram-negative, slow-growing rod, belongs to the normal flora of mucous membranes. Infections of the hand including this pathogen, are described in human bite and clenched fist injuries. Our case demonstrates another possibility of wound contamination with normal oral flora causing Eikenella corrodens infection. The consequences due to the delay of appropriate therapy are discussed.

Bacteroides Infections↗
PubMed1986

Mutational analysis of the coordinate expression of the yeast tRNAArg-tRNAAsp gene tandem.

tRNA genes occur in the yeast genome as highly dispersed and independent transcriptional units. The 5'-tRNAArg-tRNAAsp-3' gene tandem, separated by a 10-base-pair spacer sequence, thus represents a rare case of tight clustering. Previous in vitro studies did not reveal any primary transcript from the tRNAAsp gene, but rather a dimeric precursor containing both gene sequences plus spacer, which undergoes a series of maturation steps. This seems anomalous since the tRNAAsp gene contains the sequences necessary for its own transcription. We found that site-directed mutation of the highly conserved C at position 56 to a G in the tRNAArg gene suppresses all transcription and does not activate the tRNAAsp gene. Precise deletion of the entire tRNAArg gene gives a similar result. Rescue of tRNAAsp gene transcription is effected either by the precise deletion of both the tRNAArg gene and spacer or by the precise deletion of this gene with concomitant introduction of an artificial RNA polymerase III start site in the spacer. This artificial start site is ineffective if the tRNAArg gene is present upstream.

Base Sequence↗
PubMed1986

Regeneration of the eight cranial nerve. I. Anatomic verification in the bullfrog.

The regenerative capacity of the eight cranial nerve of the bullfrog, Rana catesbeiana, was investigated. The nerve was sectioned between the ganglion and the brain stem in 16 experimental animals. Horseradish peroxidase was extracellularly injected distal to the site of the nerve section five or more weeks postoperatively. Labeled fibers were identified histologically and their central nervous system projections studied. The findings were as follows: 1. The eight cranial nerve of the bullfrog regenerated after preganglionic axotomy. 2. Fibers of all sizes regenerated. The regenerated fibers in the nerve were disorderly at the site of nerve section. Most fibers entered the brain stem and formed a vestibuloauditory tract, although some "escaped" and coursed along the brain stem. 3. The regenerated vestibuloauditory tract was situated more laterally than normal, with thick and thin fibers intermixed. 4. Regenerated tertiary fibers were long and tortuous and had unusual trajectories. 5. All vestibuloauditory nuclei received thick and thin afferent fibers.

Animals↗
PubMed1985

Genetic basis for species vulnerability in the cheetah.

A population genetic survey of over 200 structural loci previously revealed that the South African cheetah (Acinonyx jubatus jubatus) has an extreme paucity of genetic variability, probably as a consequence of a severe population bottleneck in its recent past. The genetic monomorphism of the species is here extended to the major histocompatibility complex, since 14 reciprocal skin grafts between unrelated cheetahs were accepted. The apparent consequences of such genetic uniformity to the species include (i) great difficulty in captive breeding, (ii) a high degree of juvenile mortality in captivity and in the wild, and (iii) a high frequency of spermatozoal abnormalities in ejaculates. The species vulnerability of the cheetah was demonstrated by an epizootic of coronavirus-associated feline infectious peritonitis in an Oregon breeding colony in 1983. Exposure and spread of the coronavirus, which has a very low morbidity in domestic cats (approximately 1 percent), has decimated a heretofore productive and healthy captive population. The extreme genetic monomorphism, especially at the major histocompatibility complex, and the apparent hypersensitivity of the cheetah to a viral pathogen may be related, and provide a biological basis for understanding the adaptive significance of abundant genetic variation in outbred mammalian species.

Acinonyx↗
PubMed1985

Use of polytetrafluorinated ethylene compound in peripheral nerve grafting. An experimental study.

The suitability of polytetrafluorinated ethylene compound (Gore-tex) tubing in peripheral nerve grafting was studied using a rat sciatic nerve model. Thick-walled (0.36 mm) tubing was compared with thin-walled tubing (17 mm). Thin-walled tubing gave a favorable functional and microscopic result in five of seven animals, while thick-walled tubing gave a favorable graft result in three of six animals. The results achieved with the thin-walled tubing were comparable to those achieved using nerve grafts and vein interposition grafts.

Animals↗
PubMed1984

Lariat structures are in vivo intermediates in yeast pre-mRNA splicing.

Transcripts from an ADC1-actin gene fusion containing the yeast actin intron are efficiently spliced in vivo. Four distinct forms of the excised actin intron are found in poly(A)- RNA from yeast carrying this transcription unit on a multicopy plasmid. Two of them migrate abnormally slowly in polyacrylamide gels, and one of these contains a block to reverse transcription at the conserved UACUAAC sequence (TACTAAC box). We also detect a larger RNA in the poly(A)+ fraction with abnormal gel mobility and the same reverse transcriptase block. Analysis of the major species of excised actin intron, labeled with 32P in vivo, reveals the presence of a branch at the third A in the UACUAAC sequence. This A is linked via a 3'-5' phosphodiester bond to the downstream C, and via a 2'-5' phosphodiester bond to a G, presumably from the 5' end of the intron. Thus this intron RNA is in the form of a lariat.

Actins↗
PubMed1984

Teratomas of the head and neck in childhood.

Teratomas are tumors consisting of tissue arising from all three embryonic germ layers. Their occurrence in the head and neck region is rare. Three patients with this lesion are presented. Although exhibiting progressive uncoordinated growth, histologic evidence of malignancy in the head and neck form of this tumor is distinctly uncommon. Mortality associated with teratomas is most often secondary to respiratory compromise. Complete surgical extirpation is the treatment of choice to lower mortality and recurrences. The use of fine needle aspiration in the management of neck masses in children is discussed.

Biopsy, Needle↗
PubMed1982

Smoking reduction: a comparison of the effectiveness of rapid smoking and increasing delay training.

The relative effectiveness of two treatment procedures in facilitating self-control of smoking behavior was compared. One week before treatment, subjects self-monitored number of cigarettes smoked. On the days of treatment, subjects were given pre- and postsession self-control tests; subjects were given a lit cigarette and were asked to withstand the temptation of taking a puff during an imposed delay period. After five days of two-hour sessions in which subjects' smoking was paced wtih either increasing delays or rapid smoking, subjects again were asked to self-monitor their smoking for one week. Increasing delay induced better self-control scores than did rapid smoking. Both groups were not significantly different in number of cigarettes smoked.

Female↗
PubMed1982

Smoking reduction: a comparison of the effectiveness of rapid smoking and increasing delay training.

The relative effectiveness of two treatment procedures in facilitating self-control of smoking behavior was compared. One week before treatment, subjects self-monitored number of cigarettes smoked. On the days of treatment, subjects were given pre- and postsession self-control tests; subjects were given a lit cigarette and were asked to withstand the temptation of taking a puff during an imposed delay period. After five days of two-hour sessions in which subjects' smoking was paced with either increasing delays or rapid smoking, subjects again were asked to self-monitor their smoking for one week. Increasing delay induced better self-control scores than did rapid smoking. Both groups were not significantly different in number of cigarettes smoked.

Adult↗