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Biomedical subjects

J J Keene

Publications and source records attributed to J J Keene.

11 recordsLinked to original sources
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↗
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↗
PubMedDate not supplied

Prolonged medial forebrain bundle unit responses to rewarding and aversive intracranial stimuli.

In unanesthetized cerveau isolé rats, brief medial forebrain bundle (MFB) and dorsal midbrain reticular (RET) stimulus trains elicited prolonged MFB unit responses lasting up to ten or more seconds. On the MFB unit responses studied, the effects of MFB and RET stimuli were basically similar, although the stimulations were probably rewarding and aversive respectively. These data agree with the previously reported anatomical localization, in medial regions of thalamus and pallidum, of opposite single cell responses to the behaviorally opposite inputs, and suggest that unit responses to rewarding stimuli should not be characterized as reward-related when aversive stimuli elicit similar responses in the same unit.

Animals↗
PubMedDate not supplied

Arteriosclerotic changes within the diabetic oral vasculature.

Microscopic sections of diabetic, arteriosclerotic nondiabetic, and nondiabetic nonarteriosclerotic human palate were qualitatively evaluated for small artery colloidal-iron-positive, acid mucopolysaccharide content. The association of abnormal colloidal-iron-positive material with structural detail in the arterial wall was clarified by comparison with specimens of amputated diabetic human legs.

Adult↗
PubMedDate not supplied

Treatment of an unusual case of fusion.

An unusual example of anterior tooth fusion is presented in which the involved tooth had one crown, one talon cusp, two roots, and three root canals. Despite extensive multidisciplinary consultations, treatment failed, resulting in extraction of the tooth.

Child↗