Search PubMed⌕ Search

Biomedical subjects

J A Wallace

Publications and source records attributed to J A Wallace.

At least 19 recordsLinked to original sources
PubMed1999

Differential regulation of the Kar3p kinesin-related protein by two associated proteins, Cik1p and Vik1p.

The mechanisms by which kinesin-related proteins interact with other proteins to carry out specific cellular processes is poorly understood. The kinesin-related protein, Kar3p, has been implicated in many microtubule functions in yeast. Some of these functions require interaction with the Cik1 protein (Page, B.D., L.L. Satterwhite, M.D. Rose, and M. Snyder. 1994. J. Cell Biol. 124:507-519). We have identified a Saccharomyces cerevisiae gene, named VIK1, encoding a protein with sequence and structural similarity to Cik1p. The Vik1 protein is detected in vegetatively growing cells but not in mating pheromone-treated cells. Vik1p physically associates with Kar3p in a complex separate from that of the Kar3p-Cik1p complex. Vik1p localizes to the spindle-pole body region in a Kar3p-dependent manner. Reciprocally, concentration of Kar3p at the spindle poles during vegetative growth requires the presence of Vik1p, but not Cik1p. Phenotypic analysis suggests that Cik1p and Vik1p are involved in different Kar3p functions. Disruption of VIK1 causes increased resistance to the microtubule depolymerizing drug benomyl and partially suppresses growth defects of cik1Delta mutants. The vik1Delta and kar3Delta mutations, but not cik1Delta, partially suppresses the temperature-sensitive growth defect of strains lacking the function of two other yeast kinesin-related proteins, Cin8p and Kip1p. Our results indicate that Kar3p forms functionally distinct complexes with Cik1p and Vik1p to participate in different microtubule-mediated events within the same cell.

Amino Acid Sequence↗
PubMed1998

Efficacy of cobalt chelates in the rabbit eye model for epithelial herpetic keratitis.

PURPOSE: A new class of antiviral agent, cobalt chelates (the CTC series), was evaluated for treating epithelial herpetic keratitis, consequent stromal disease being the major infectious cause of blindness in industrial nations. METHODS: Effects of CTC complexes were monitored in cell cultures and in a rabbit eye model, either infected with herpes simplex virus type 1 (HSV-1) or uninfected. Several antiviral concentrations of CTC complexes nontoxic to Vero cells were administered to rabbit eyes with HSV-1-induced keratitis. Corneal surface virus titers were measured, and corneal lesions of epithelial keratitis were monitored by slit-lamp microscopy and scored. Recovery rates and incidence were compared in eyes treated with CTC complexes, placebo, or clinically formulated trifluorothymidine (Viroptic), using nonparametric statistics. RESULTS: All CTC complexes inhibited HSV-1 replication in vitro, CTC-96 being best. CTC-96, CTC-23, and CTC-67 eliminated (<1 plaque-forming unit[pfu]) corneal surface HSV-1 (otherwise >10(5) pfu) in order of descending potency, but CTC-82 was ineffective. CTC-96 (either 5 microg/ml six times daily or 10 microg/ml five times daily) accelerated herpetic dendritic keratitis recovery better than or the same as trifluorothymidine (10 mg/ml nine times daily). CTC complexes were nontoxic to Vero cells continuously exposed to < or =25 microg/ml; 50 microg/ml of CTC 96 nine times daily did not irritate uninfected rabbit eyes. CONCLUSION: Topical CTC-96 applications were at least as effective as Viroptic in diminishing disease signs and corneal surface virus at concentrations less than one-thousandth that of Viroptic.

Animals↗
PubMed1996

Tyrosine hydroxylase-containing neurons in the spinal cord of the chicken. I. Development and analysis of catecholamine synthesis capabilities.

1. The development of tyrosine hydroxylase-immunoreactive (TH-IR) neurons was examined in the spinal cord of the chick embryo and hatchling. 2. Two groups of TH-IR cells are described, both of which appear to reach their full complement in number relatively late in embryonic development. One group is comprised of numerous cells located ventral to the central canal which make direct contact with the lumen of the canal. The other group consists of large multipolar neurons that reside in the dorsal horn, more commonly along the outer margin of the gray matter within lamina I and II, and less frequently deeper in the dorsal horn within medial portions of laminae V, VI or VII. 3. TH-IR cells ventral to the central canal in the chick are comparable in location to dopamine (DA)-containing spinal cord cells in lower vertebrate species. In contrast, the dorsally-suited TH-IR cells in the chick are known only to occur in similar positions in higher vertebrates. Therefore, the chick is novel in that the presence of both groups of TH-IR cells appearing together in significant numbers within the spinal cord has not been shown in any other species studied to date. 4. The TH-containing cells in the chick cord do not appear to contain the catecholamine biosynthesis enzymes, DBH or PNMT. Moreover, using anti-DA immunocytochemistry, neither group of TH-IR cells demonstrated detectable levels of DA in control animals nor in animals pretreated with inhibitors of MAO (MAO-I). 5. However, a difference was noted though between the two TH-IR cell groups in terms of their responses to exogenously supplied L-DOPA, the immediate precursor to DA. With the administration of L-DOPA and a MAO-I to chick hatchlings, cells in the region ventral to the central canal stained intensely for DA. In contrast, the same treatment failed to produce DA-immunoreactive cells in the dorsal horn. 6. One reasonable hypothesis for these results is that the TH-IR cells ventral to the central canal contain an active form of AADC, the enzyme that converts L-DOPA to DA. With this interpretation, if these cells can produce DA from L-DOPA, yet do not appear to synthesize DA endogenously, it would appear that the TH enzyme contained in these cells occurs in an inactive form. Whether the TH enzyme in the dorsally located immunoreactive cells is also inactive is uncertain since it remains unclear whether they contain AADC.

Animals↗
PubMed1996

Blood mercury levels with amalgam retroseals: a longitudinal study.

A clinical study was performed to determine if placement of an amalgam retroseal resulted in elevated blood mercury levels. Ten subjects had blood drawn 7 days before and immediately before placement of an amalgam retroseal. Postoperative blood draws occurred at 7 and 30 days. Blood samples were analyzed for mercury content by Cold-Vapor Atomic Absorption Spectrophotometry. No statistically significant increase in blood mercury levels was detected at 7 and 30 days after placement of an amalgam retroseal as compared with preoperative levels (p = 0.97). Findings support the hypothesis that placement of an amalgam retroseal does not result in significant elevations of blood mercury levels.

Adult↗
PubMed1996

Transantral endodontic surgery.

A case is presented in which periradicular maxillary molar surgery was performed with the transantral approach. Included is a discussion of the related anatomy, physiology, and pathology of the maxillary sinus.

Adult↗
PubMed1994

Dens invaginatus: another use for the ultrasonic.

Dens invaginatus is an anomaly which has numerous and complex forms. Whenever endodontic therapy involving such a tooth becomes necessary, the clinician must be aware of the various treatment modalities available to facilitate proper care. Presented in this case report is a maxillary lateral incisor having the anomaly dens invaginatus in which both surgical and nonsurgical treatment was required. The surgical phase was facilitated through the use of ultrasonic instrumentation.

Child↗
PubMed1994

An in vitro comparison of microleakage of restorative materials in the pulp chambers of human molar teeth.

Ninety-six human molars were accessed. After flattening of the occlusal surface and removal of the apical two-thirds of the roots, the remaining canal space was instrumented by conventional methods. The teeth were divided into six groups of 15 teeth with three positive and three negative controls. The six experimental groups were based on the material used to restore the pulp chamber and remaining canal space: 1, gutta-percha with sealer; 2, amalgam; 3, IRM; 4, light-cured posterior composite; 5, chemical-cured core paste; and 6, light-cured glass ionomer. After placement of the restorative material, the teeth were thermocycled and evaluated for microleakage using 2% methylene blue dye and incremental sectioning. The amalgam and glass ionomer groups showed significantly less leakage than the other materials. The composite, core paste, and IRM did not differ significantly from one another. The gutta-percha with sealer group showed significantly greater leakage than all other groups.

Analysis of Variance↗
PubMed1993

Sialadenosis in bulimia. A new treatment.

OBJECTIVE: To see whether a cholinomimetic medication would help resolve the parotid gland enlargement associated with self-induced vomiting in bulimic patients. SETTING/DESIGN: The medication was administered on an inpatient eating disorder unit to bulimic patients with refractory sialadenosis. INTERVENTION: Pilocarpine hydrochloride drops were administered orally at a dosage of 1.25 to 5.0 mg/d until the parotid gland enlargement was significantly reduced. RESULTS: There was a marked diminution in the size of the parotid gland enlargement. CONCLUSION: Pilocarpine has proved to be beneficial in the treatment of sialadenosis in bulimic patients.

Adult↗
PubMed1991

Castable glass ceramic crowns and their reaction to endodontic therapy.

The purpose of this investigation was to determine how castable glass (Dicor) crowns would react to both cold testing and endodontic access intervention. Full crown preparations were made on six extracted maxillary teeth. The teeth were then forwarded to Dentsply International, York, Pa. Six castable glass crowns were fabricated to fit these teeth and returned to us. Subsequently the teeth were dried and the crowns were cemented. Scanning electron micrographs of the cemented crowns were made, and endodontic access openings were drilled. The teeth were also cold tested with standard methods. The teeth were then again subjected to scanning electron microscopy to determine any changes the crowns might have undergone. One crown cracked around the gingival collar as scanning electron microscopy was performed. The other crowns did not exhibit any problems such as cracking or crazing from either the access openings or the cold testing.

Ceramics↗
PubMed1991

Pulse oximetry as a diagnostic tool of pulpal vitality.

The technology of pulse oximetry has allowed significant advances in the medical field yet its use in dentistry has been virtually unexplored. This study investigates the potential of the pulse oximeter to detect vascular integrity within the human tooth. Forty-nine young adults were evaluated for the vitality of their maxillary central incisors utilizing thermal, electrical, and oximetric techniques. The pulse oximeter was found to indicate a pulse rate and oxygen saturation reading for the vital teeth and no readings for the teeth previously endodontically treated. The accuracy of this diagnostic method supports the need for additional study in the use of the pulse oximeter to interpret the pathological processes of the pulp.

Adult↗
PubMed1991

Effects of hydrogen sulfide exposure on surface properties of lung surfactant.

Hydrogen sulfide is an irritant and chemical asphyxiant gas that exerts its primary toxic effects on the respiratory and neurological systems. Exposure to hydrogen sulfide above a threshold value of 200-300 ppm is characterized by the sudden onset of hemorrhagic pulmonary edema. The purpose of this study was to determine whether this response is associated with changes in the surface properties of pulmonary surfactant. Bronchoalveolar lavage fluid was retrieved from the lungs of Fischer 344 rats exposed to two concentrations of hydrogen sulfide or fresh air for 4 h. Surface tension-lowering properties were assayed using a captive bubble surface tensiometer. Lung injury was assessed by histopathology and measurements of total protein and lactate dehydrogenase activity in the lavagate. Marked abnormalities in surfactant activity were demonstrated in the lavagates from rats exposed to the highest concentration (300 ppm) of hydrogen sulfide. These involved the properties of adsorption to the air-water interface and surface tension lowering under quasi-static interfacial compression. Exposure to 200 ppm hydrogen sulfide had no effect on minimum surface tension despite a significant increase in protein and lactate dehydrogenase in the lavagate. This would suggest a threshold-type response for the inhibition of surfactant activity by hydrogen sulfide. In vitro studies using normal rat surfactant showed that the abnormalities in surfactant activity were due to inhibitors in the edema fluid and not to a direct effect of sulfide on surfactant. The pathophysiological consequences of increased alveolar surface tension after hydrogen sulfide exposure may need to be considered in the clinical setting.

Adsorption↗
PubMed1990

Pulpal and root sensitivity rated to periodontal therapy.

The purpose of this clinical investigation was to determine if periodontal treatment consisting of scaling, root planing, and periodontal surgery produced any change in pulpal or root sensitivity. Ten patients were tested, with a total of 84 observations. There were 42 periodontally treated teeth, with 42 contralateral teeth serving as control specimens. The teeth were evaluated with stimuli from an electric pulp tester, cold, and air. The electric pulp tester was found to be reliable in assessing the pulpal sensitivity. Neither the amount of periodontal destruction nor the extent of periodontal treatment had any effect on the pulp. Scaling and root planing had no significant effect on root sensitivity. Periodontal surgery was directly related to root sensitivity in terms of the extent of root surface exposure. An association was observed clinically between plaque accumulation after periodontal surgery and root sensitivity.

Adult↗
PubMed1990

Epithelial rests' function in replantation: is splinting necessary in replantation?

The problem of resorption during replantation in relationship to the epithelial rests and a lack of splinting was studied. Ten mongrel dogs were used. Two dogs served as control subjects, while eight had their mandibular incisors intentionally replanted and studied histologically. It was observed that where rests of Malassez were present we did not see resorption, and the lack of splinting did not result in resorption or loss of teeth. It appears we can stain epithelial rests of Malassez with immunofluorescent antibodies and use this technique for further study of this tissue.

Animals↗
PubMed1988

Co-localization of tyrosine hydroxylase (TH)- and serotonin (5-HT)-immunoreactive innervation in the rat pituitary gland.

Adult male Sprague-Dawley rats were examined for possible co-localization of tyrosine hydroxylase (TH) and serotonin (5-HT) within innervation of the pituitary neurointermediate lobe. Use of sheep antiserum to TH and a secondary antibody coupled to fluorescein isothiocyanate (FITC), followed by rabbit anti-5-HT, then rhodamine-coupled second antibody, produced co-existent staining in some, but not all fibers of both the neural and intermediate lobes, using paraffin embedded tissues. Application of a combination of the two primary antibodies followed by sequential application of secondary antibody also resulted in co-localized antigens in selected fibers. Multiple 'classic' neurotransmitters within the same nerve terminals may modulate selected areas of endocrine tissue to control hormone release.

Animals↗