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Biomedical subjects

B Litovsky

Publications and source records attributed to B Litovsky.

6 recordsLinked to original sources
PubMed1993

Presence but not synthesis of thyrotrophin-releasing hormone in rat salivary glands detected by radioimmunoassay and northern blot analysis.

Thyrotrophin-releasing hormone (TRH) is one of the ubiquitous peptides first isolated from hypothalamus. This study sought to examine if it could also be detected in rat submandibular salivary glands, as can other neurogastrointestinal peptides. Radioimmunoassay of submandibular gland homogenates revealed TRH-like immunoreactivity in all samples from male rats (637.34 pg/gland +/- 166.17, n = 15). In contrast, Northern blot analysis to determine whether the peptide was locally synthesized in the glands failed to detect TRH mRNA. Consequently, the presence of TRH in the glands (as revealed by radioimmunoassay) could be associated with binding to presumptive TRH receptors in the mediation of physiological activities.

Animals↗
PubMed1992

[Decrease of pineal AMPc and TOH activity in the superior cervical ganglia after ablation of submaxillary glands in rats].

In order to investigate a possible functional relationship between the submandibular salivary gland (SSG) and the central nervous system (CNS), we have extirpated the salivary organs from thirty male rats. Twenty days after ablation both the pineal glands and the cervical superior ganglions (CSG) were dissected, homogenized and frozen until AMPc and TOH were assayed respectively. We observed a significant decrease in pineal AMPc (53.9 +/- 6.2 vs 76.1 +/- 7.6% of maximum value; p less than 0.02) which seems to be linked with a significant drop in TOH activity measured at CSG level (1.5 +/- 0.6 vs 3.7 +/- 0.9 nmoles of DOPA/h/pair GCS; p less than 0.03). Our results suggest that both findings might be due to the lack of NGF normally reaching the CSG from SSG. This data reinforces the idea of a functional link between SSG and CNS via the pineal gland.

Animals↗
PubMed1990

["Push-pull" perfusion technic, a new approach applied to the study of transdentinal fluid].

The flux through the dentin tubuli is at the origin of the hydrodynamic theory of tooth sensitivity. After a review of the various in vivo techniques reported in the literature, this study describes an original method of dentin perfusion--so called "push-pull" and specific to this topic. With this technique, the authors have demonstrated the kinetics of this flux, as well as the effect of some factors (age, colchicine, ouabain), on transdentinal fluid exchanges. The analysis of all these results suggests that a combination of active and passive movements could be at the origin of this flux, the temporary inhibition of which could present major advantages in current Periodontics practice.

Age Factors↗
PubMed1990

[Scanning electron microscope view of dentin exposed to CO2 laser radiation].

In order to better define the effects of CO2 Laser rays on dentine, 10 healthy human teeth to be removed and 64 recently removed healthy human teeth were prepared and irradiated according to the classic protocol used in clinical periodontics, and observed with a scanning electron microscope. The examination of these samples confirms the phenomena of dentin fusion and recrystallization. But these alterations result in the appearance of a reorganized superficial layer consisting of unevenly juxtaposed craters formed by the pin-point action of the laser beam. These craters present numerous fissures and openings of variable diameter. They do not form a homogeneous surface, since chips may be raised, demonstrating the fragility of the reorganized layer and a lack of cohesion of the underlying dentine. The modified dentine layer also disappears when a curette is used, revealing a very uneven surface crossed with small cracks and where the tubule openings become visible. Our results, unlike many more optimistic studies, still prompt us to exert caution in the systematic use of CO2 lasers in Periodontics.

Adult↗
PubMed1988

[Changes induced by ouabain and colchicine in the transdentinal flow estimated in vivo by perfusion: the "push-pull" of the incisors of rats].

The active or passive mechanisms regulating the various movements of dentinal fluid have not yet been sufficiently studied. For this reason different "in vivo" factors that may modulate the kinetics of transdentinal flow were investigated. After systemic administration of a radiotracer in rats, the kinetics were examined with a push-pull perfusion device fixed to the incisor dentin. The drugs chosen, i.e. ouabain and colchicine, were for their respective effects on microtubules and on the ATPase-dependent Na+ K+ pump, since these two factors are involved in the transport process. Anesthetized animals were prepared to allow intravenous injection of iodine 125 (0,5 to 0,7 mCi), carotid sampling, and perfusion of upper incisors. Ouabain induced a very significant decrease in transdentinal flow, which was particularly evident in younger animals (2,81 x 10(-2) % vs 0,04 x 10(-2)%, p less than 0,05). However, colchicine produced two different kinds of results : at low doses (3,5 to 5 mg/100 g) the pulsatile pattern of the curves was partially inhibited, whereas, at higher doses (6 to 7 mg/100 g), the transdentinal flow of radioactivity increased. These results suggest that a combination of active and passive transport may be involved in the various movements of this fluid.

Animals↗