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Biomedical subjects

Y Zilberman

Publications and source records attributed to Y Zilberman.

At least 19 recordsLinked to original sources
PubMed1992

Multiple effects of staurosporine, a kinase inhibitor, on thymocyte functions. Comparison with the effect of tyrosine kinase inhibitors.

The effects of staurosporine, a protein kinase inhibitor, on the signal transduction and proliferation of thymocytes were studied. Signal transduction in response to Concanavalin A (Con A) as well as Concanavalin A (Con A)-induced augmentation of [3H]inositol incorporation into phospholipids were inhibited by staurosporine (> or = 10(-8) M). Staurosporine inhibited thymocyte proliferation in response to Con A in the presence or absence of the phorbol ester, phorbol myristate acetate (TPA) (10 nM). This inhibition was observed regardless of whether staurosporine was added together with Con A or 3 hr later. High concentrations of staurosporine (> 10(-8) M) inhibited thymocyte proliferation induced by the calcium ionophore A23187 and the phorbol ester TPA, whereas lower concentrations of the inhibitor (< or = 10(-8) M) enhanced thymidine incorporation in response to these activators. This dual effect of staurosporine was also observed in the presence of the staurosporine-related kinase inhibitor, K252a. In contrast, the tyrosine kinase inhibitor, tyrphostin AG490, inhibited the response to A23187 and TPA at all concentrations of the inhibitor and no augmentation was seen. Interleukin 2 (IL-2)-driven mitogenesis in IL-2-dependent cells was also inhibited by staurosporine. We suggest that the inhibition of thymocyte proliferation by staurosporine results from inhibition of both protein kinase C and tyrosine kinase: the augmentation of the response to A23187 and TPA results from inhibition of protein kinase C. Inhibition of signal transduction as well as inhibition of IL-2-driven mitogenesis result from inhibition of tyrosine kinase.

Alkaloids↗
PubMed1992

Stimulatory and inhibitory effects of 1,25-dihydroxyvitamin D3 on thymocyte mitogenesis induced by phorbol ester and calcium ionophore.

UNLABELLED: Mouse medullary thymocytes have specific receptors for 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). The mitogenic stimulation of these cells by phytohemagglutinin in the presence or absence of the phorbol ester TPA is inhibited by 1,25(OH)2D3. The calcium ionophore A23187 did not reverse the inhibition by 1,25(OH)2D3 of phytohemagglutinin. Stimulation of thymocytes with either TPA or A23187 alone did not result in proliferation. Co-stimulation of the thymocytes with TPA and A23187 induces cell proliferation. 1,25(OH)2D3 markedly enhanced the TPA and A23187-induced cell proliferation even when added 4 h after the initiation of the culture. In contrast, DNA synthesis by thymocytes incubated for 4 h in the presence of TPA and A23187 and then cultured in medium containing 1,25(OH)2D3 but in the absence of both TPA and A23187, was inhibited by 1,25(OH)2D3. The extent of inhibition was comparable to the inhibition of lectin-induced stimulation by the hormone. Using monoclonal antibodies to neutralize IL-2 and block IL-2 receptors we showed that 1,25(OH)2D3 enhanced the IL-2-independent component of the A23187- and TPA-induced mitogenesis. IN CONCLUSION: (1) The nature and presence of the mitogenic signal determines whether 1,25(OH)2D3 enhances or inhibits thymocyte stimulation. (2) Both stimulatory and inhibitory actions of 1,25(OH)2D3 seem to take place at points distal to the initial increase in intracellular calcium or activation of protein kinase C.

Calcimycin↗
PubMed1992

Quintuplets with clefts: follow-up at ten years of age.

A set of quintuplets, three of which were born with various degrees of oral clefting, were followed up to the age of 10 years. Study models, as well as panoramic and intraoral roentgenograms were collected at ages 5 and 10 years. Cephalometric roentgenograms were added at the age of 10 years. Analysis of the growth charts for height and weight indicated normal somatic development, save for a persistent, albeit diminishing, lag for the two most severely affected siblings. The latter also demonstrated a more vertical craniofacial growth pattern. The dental arch dimensions were within normal range, except for the maxillary and mandibular widths in the two more affected siblings, who also exhibited a delay of one or two stages of dental development in an intersibling comparison. These findings indicate that in the more severely affected siblings, there was only partial growth catch-up at the age of 10 years.

Cephalometry↗
PubMed1991

Functional and esthetic rehabilitation of an adolescent cleft lip and palate patient.

Many patients with clefts that also affect the alveolar ridge present with congenital absence of the permanent maxillary lateral incisors. This paper describes the treatment of an adolescent cleft lip and palate patient whose missing and unesthetic maxillary incisors were replaced by a combination of fixed and removable partial dentures.

Adolescent↗
PubMed1979

Structural and kinetic studies on the solubilization of lecithin by sodium deoxycholate.

Mixed dispersions of egg phosphatidylcholine (PC) and the bile salt sodium deoxycholate (DOC) were prepared by various methods, and their turbidities and proton magnetic resonance spectra were studied as a function of time. The spectra of dispersions prepared by dissolving both components in a common organic solvent and replacing the organic solvent by water did not change with time, indicating that the mixed aggregates formed represent "a state of equilibrium". In the 1H NMR spectra of these mixed aggregates, only signals from small mixed micellar structures were narrow enough to be observed. The dependence of the NMR line widths on the molar ratio of DOC to PC (R) is interpreted in terms of a model for the PC--DOC mixed micelles, according to which PC is arranged as a curved bilayer, the curvature of which increases with increasing R. Upon mixing PC with aqueous solutions of DOC, we found that the mixed aggregates formed are slowly reorganized and ultimately reach the same state of equilibrium. This reorganization was found to be a pseudo-first-order process, the rate constant of which depends linearly upon the detergent concentration. This process involves saturation of the outer bilayers of the multilamellar PC by detergent, followed by transformation of these bilayers into mixed micelles. It is concluded that the solubilization occurs through consecutive "peeling off" of lecithin bilayers.

Deoxycholic Acid↗
PubMed1979

The use of phospholipid liposomes for lithium administration. Polydipsic effect and tissue distribution of lithium.

Administration of lithium entrapped in phospholipid liposomes increased the lithium-induced polydipsia, but did not accelerate the onset of this effect. It also resulted in a larger accumulation of lithium in the liver, kidney and spleen, but not in the brain. The time course of polydipsia suggests that it depends on the intracellular lithium concentration. However, the rate of development of this effect depends on some additional factor.

Animals↗
PubMed1978

The palatally impacted canine: a new approach to treatment.

A method for the application of traction to misplaced maxillary canines in the palate is described. The treatment approach is from the palatal side, with initial traction applied in a lingually downward direction to prevent interference with the neighboring teeth. Emphasis is placed on the suitability of the method as an adjunct to almost any of the established techniques. In this way improving their efficiency in treating the over-all orthodontic problem.

Child↗
PubMed1978

Non-routine extractions in orthodontic treatment.

A four-unit symmetrical premolar extraction case demands meticulous levelling, overjet reduction, space closure, rotating, paralleling and torqueing to justify the gambit of having extracted the teeth at the commencement of treatment. This involves the patient in complex therapy which may, for any of several reasons, be contra-indicated for that particular patient, though a decision based on the plaster casts alone may have upheld such an approach. The purpose of this article is to discourage automatic decisions to extract first premolars in orthodontic extraction cases. The clinician is offered a classification of special cases in which an alternative should be sought, based on careful consideration of the general dental, facial, physical, psychological and economic state of the patient.

Acute Disease↗
PubMed1977

The effect of topical application with an organic and inorganic fluoride compound on the inhibition of dental plaque in humans.

Accumulation of dental plaque for 3 and 7 days respectively was determined by calculating the difference between the postcollection and precollection weights of enamel slabs attached to orthodontic bands cemented to the upper first molars of 3 subjects. Pretreatment of the enamel slabs with amine-fluoride or -chloride respectively-at an equivalent amine concentration-prevented plaque deposition on the slabs, whereas pretreatment with sodium monofluorophosphate was less effective. The fluoride concentrations of all fluoride-pretreated enamel slabs were similar. No convincing demonstration of significant differences between the treatments could be predicted in view of the discrepancy in results at the 3- and 7-day test periods.

Adult↗
PubMed1976

A comparative study of tooth and dental arch dimensions in Jewish children of different ethnic descent. I. Kurds and Yemenites.

Dental casts of 99 Kurdish and 98 Yemenite Jewish children evenly distributed between the sexes, aged 12 years, were measured for mesiodistal and buccolingual tooth dimensions, and arch depth and width. Dental dimensions showed significant differences between the two groups in certain permanent teeth in mesiodistal length, while in the buccolingual diameter the differences did not reach statistical significance. Dental arch form in Kurdish children was more rounded due to significantly bigger arch width, while arch depth was not significantly different from Yemenites. Intragroup sex differences were found in both groups with reference to arch dimensions, while in the dental parameters they were more strongly expressed in Kurdish children.

Child↗
PubMed1976

Arch expansion: an integral part of surgical orthodontics.

Two cases of mandibular prognathism have been presented. In both cases expansion of the dental arches was performed prior to surgery for the achievement of good and stable interarch relationships postoperatively. In the first case maxillary arch was expanded with a rapid-expansion technique; in the second, expansion of the mandibular arch was performed with a modified removable Coffine appliance. Results at 15 months and 2 years after retention showed the expansion to be stable.

Adolescent↗
PubMed1976

Iatrogenic exfoliation of teeth by the incorrect use of orthodontic elastic bands.

Four cases of improper use of elastic bands for minor orthodontic treatment are described. For all the patients, the treated teeth were damaged and local surgical intervention was necessary. To prevent complications when elastic bands are being used, the dentist must provide stabilization of the elastic bands by brackets, bands, or bonded attachments, inform the patient about the possibility of losing the rubber elastic band, and mark the elastic rubber by radiopaque material. Every effort must be made to preserve the damaged anterior teeth by fixation and surgical treatment.

Child↗