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Biomedical subjects

J J Keene

Publications and source records attributed to J J Keene.

At least 19 recordsLinked to original sources
PubMed2001

Cardiopulmonary support for emergent innominate artery repair complicating tracheal surgery.

Innominate artery rupture is a rare, but usually fatal, complication of tracheal stenosis. Although prevention is key, prompt, appropriate intervention can be life saving. Hemorrhage and airway must simultaneously be controlled. Most deaths occur from exsanguination with adequate ventilation before surgical repair can be effected. In the ideal situation, the event would occur in the operating room. We report on just such a case with concomitant respiratory failure requiring cardiopulmonary support in order to accomplish definitive therapy.

Brachiocephalic Trunk↗
PubMed1998

Case report. Use of an argon laser to treat drug-induced gingival overgrowth.

This article explores the use of an argon laser to treat severe drug-induced gingival overgrowth. The patient was being treated with phenytoin (Dilantin, Parke-Davis), cyclosporine and a calcium channel blocker. He had undergone a kidney transplantation and had insulin-dependent diabetes mellitus. He had severe gingival overgrowth, which prevented him from wearing his removable prostheses, and a superimposed Candida albicans infection. An argon laser was used to excise the gingival overgrowth so new maxillary and mandibular prostheses could be fabricated.

Anticonvulsants↗
PubMed1993

Phosphorylated nutrient uptake by Treponema denticola and other potential periodontopathogens.

Nutrient uptake may contribute to the survival of certain potential periodontopathogens in the competitive environment of the gingival sulcus. This study was conducted to assess the uptake of commercially available, key radiolabelled phosphorylated compounds by Treponema denticola. There was a linear relationship in the uptake of ATP and G-1-P with cell concentrations of 0.1-2.5 mg of cell dry weight. This uptake reached a steady state within 15 min, and at temperatures of 25-37 degrees C the uptake ranged between 13-21%. At 50 degrees C, or above 50 degrees C the assay cells took up 0-1% of the assay nutrients. The maximum uptake of ATP was 47.5, 38 and 47.6 pmoles for serovars a, b and c. G-1-P yielded maximum uptake values of 306, 304, and 306 pmoles respectively. Significant uptake of ATP, or G-1-P occurred at pH 4.8 for serovars a, or c, while serovar b showed a broad pH range for the uptake of G-1-P. Stannous fluoride at a concentration of 0.17 mM enhanced the uptake of ATP while chlorhexidine digluconate inhibited the uptake of ATP. At concentrations usually employed (0.05-0.5 mM) the metabolic poisons 2,4-dinitrophenol, sodium azide, sodium arsenite and the ATPase inhibitor N,N1-dicyclohexylcarbodiimide did not alter significantly the uptake of ATP. The uptake of ATP, by Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Fusobacterium nucleatum and T. denticola at pH 4.8 was 13.4, 1.5, 6.9, and 18-20.4%, respectively. At pH 6.5 the uptake for the microorganisms indicated above was 22, 1.3, 6.6 and 6.2%, respectively. G-1-P showed the same trend in its uptake by A. actinomycetemcomitans, P. gingivalis, F. nucleatum and T. denticola. This study provides for the first time specific examples of phosphorylated nutrient uptake by potential periodontopathogens, and that the uptake of phosphorylated nutrients can be suppressed by oral hygienic compounds.

Adenosine Triphosphate↗
PubMed1985

Identification of Langerhans cells in human gingival epithelium.

The purpose of this study was to qualitatively compare three recent techniques of Langerhans cells detection in oral epithelium and to quantitatively compare Langerhans cells in clinically normal and clinically inflamed human gingival biopsies. Eleven subjects were selected who displayed chronic periodontitis and moderate gingival inflammation. A quadrant associated with clinically inflamed tissues was not treated, while the remaining teeth were scaled and root-planed. Two gingival biopsies were taken: clinically normal, treated tissue; and clinically inflamed, untreated tissue. Langerhans cells were stained using HLD-DR, S-100 and OKT6. They were quantitated using a standard grid for OKT6-stained sections only. Approximately 5 times as many Langerhans cells were identified in the biopsy specimens of clinically inflamed human gingiva as in clinically normal gingiva of the same patient. Of the methods studied, OKT6 was qualitatively determined to be the best for visualization of these cells. An immunologic role in the host response to chronic periodontal disease is postulated for Langerhans cells.

Adult↗
PubMed1982

A histologic evaluation of periodontal tissues adjacent to root perforations filled with Cavit.

Root perforations were created in dog premolars; thirty-one were filled with Cavit, whereas seventeen were left unfilled. The animals were killed after 1, 15, 30, 60, 120, and 180 days, and hematoxylin and eosin sections were prepared. Perforations near the gingival sulcus usually led to severe destruction, whereas those surrounded by ample bone tended to gain a favorable response, even when left unfilled.

Animals↗
PubMed1980

Insulin I125 distribution within oral tissues.

The localization of insulin I125 in oral tissues of the rat was investigated. Eight rats were made chemically diabetic in order to study the tissue distribution of insulin I125. Two nondiabetic control animals were also injected with the tracer. Another animal served as a complete control (i.e., not injected with either the diabetic inducer or insulin I125). Additional controls were sections of thyroid and liver. Experimental rats were sacrificed at preselected time intervals and autoradiographic procedures were performed subsequent to conventional histologic studies. Qualitative grain counts were made of each slide in order to compare with the background count. All oral tissues studied except dentin showed insulin I125 uptake.

Alveolar Process↗
PubMed1975

A durable chronic unit recording device with movable microelectrode.

The design of a durable chronic unit recording device with movable microelectrode suitable for cats and monkeys is presented. Sufficiently rugged to remain on cats for weeks during exploration of a single electrode tract, the device also features: choice of stereotaxic coordinates over a large horizontal area at recording time; good stereotaxic precision; capability to hold a single unit for days; excellent insulation between the recording circuit and the animal; and simplicity of design and materials which allows fabrication of numerous devices in one lab.

Animals↗
PubMed1975

Prolonged unit responses in thalamic reticular, ventral, and posterior nuclei following lateral hypothalamic and midbrain reticular stimulation.

In unanesthetized postcollicular cerveau isole rats, prolonged responses over 10 sec periods following intracranial stimulation (0.2 sec, 100 Hz, 0.5 msec. 600 muA cathodal pulses) were studied with extracellular recordings of 150 nucleus reticularis and 122 ventral and posterior thalamic units. After medial forebrain bundle (MFB) or midbrain reticular (RET) stimulation, most nucleus reticularis units showed significantly decreased firing, and the MFB and RET effects converged on 64%. None was excited. In ventral and posterior thalamus, however, long-lasting unit responses were mixed. MFB and RET stimuli elicited significantly increased firing in 17% and 20% of the units, respectively, and decreased firing in 21% and 16%, respectively. Convergence of MFB- and RET-elicited responses occurred in 25% of the cells, but none showed convergence of opposite responses which might reflect believed motivational differences between the stimuli. Similar stimuli delivered to ventral medial thalamus evoked pronounced excitation of nucleus reticularis discharge, contrasting the MFB and RET effects and confirming previous reports by others. The substantial responses elicited by MFB and RET stimuli in nucleus reticularis fulfill previously proposed criteria for definition of an arousal dimension in terms of single cell activity. The similarity of MFB and RET effects in the posterior nucleus of thalamus raises questions regarding its role in nociception.

Animals↗