Autogenous dentin graft versus alloplastic graft combined with socket shield for pre-implant socket preservation: a split-mouth randomized clinical trial.

After tooth extraction, alveolar bone resorption and labial bone plate thinning occur due to the lack of periodontal ligaments. The socket shield method was developed to preserve the alveolar ridge. A split-mouth study was performed in which eight patients were treated using alloplast with socket shield on one side (alloplast group, control) and autogenous dentin graft with socket shield on the contralateral side (dentin group, test). After 3 months, a trephine bone core was collected from all sites and evaluated by histological, histomorphometric, and radiographic analysis. Thin bony trabeculae were formed surrounding the residual alloplast, while thicker trabeculae of bone formed and fused to the autogenous dentin. The percentage of newly formed bone was significantly higher in the dentin group when compared to the alloplast group (P = 0.020). Radiographically, there was no significant difference in the mean percentage increase in bone density from preoperative to post-grafting between the two groups. Moreover, when comparing the change in labial bone level from preoperative to 3 months post-grafting between the two groups, there was no significant difference. The autogenous dentin graft combined with socket shield could be a promising technique for socket preservation.

Investigation of brain-derived neurotrophic factor (BDNF) gene expression in hypothalamus of obese rats: Modulation by omega-3 fatty acids.

PURPOSE: The aim of this study was investigating the effect of omega-3 fatty acids (ω-3 FAs) on brain-derived neurotrophic factor (BDNF) gene expression, using in vivo and in vitro models, to unravel the potential mechanisms of polyunsaturated fatty acids use in obesity. MATERIALS AND METHODS: Twenty-nine Sprague-Dawley rats were divided into three groups; lean controls fed normal chow diet for 14 weeks, obese controls fed 60% of their diet as saturated fats for 14 weeks, and ω-3 FAs-treated rats fed 60% saturated fat diet for 14 weeks with concomitant oral administration of 400 mg/kg/day ω-3 FAs, mainly docosahexaenoic acid and EPA, from week 12 to week 14. For the in vitro experiment, hypothalamic cells from six obese rats were cultured in the presence of different concentrations of ω-3 FAs to determine its direct effect on BDNF expression. RESULTS: In vivo results showed that obesity has negative effect on BDNF gene expression in rat hypothalamus that was reversed by administration of ω-3 FAs. Obese rats showed hypercholesterolemia, hypertriglyceridemia, normoinsulinemia, hyperglycemia and hyperleptinemia. Treatment with ω-3 FAs showed significant decrease in serum total cholesterol and TAG. Also serum glucose level and HOMA index were decreased significantly. In vitro results demonstrated the increase in BDNF expression by ω-3 FAs in a dose-dependent manner. CONCLUSIONS: Obesity causes down-regulation of BDNF gene expression that can be reversed by ω-3 FAs treatment, making them an interesting treatment approach for obesity and metabolic disease.

Bioglass in Alveolar Bone Regeneration in Orthodontic Patients: Randomized Controlled Clinical Trial.

This study was designed as a split-mouth randomized controlled clinical trial to evaluate the effects of a novel bioactive glass scaffold-tailored amorphous multiporous (TAMP)-for the preservation of alveolar bone following tooth extraction in class II orthodontic patients. TAMP scaffolds were prepared and sterilized. Patients were screened for eligibility, and 6 patients accounting for 14 extraction sockets were included in this stage. Sockets were randomly allocated to either control (left empty) or test (grafted with TAMP scaffold particles). Follow-up was done after 1, 2, 4, 8, and 12 to 17 wk with digital periapical radiographs to evaluate changes in crestal bone height and bone mineral density (BMD), 3-dimensional volumetric analysis of impression casts, and histologic analysis of core biopsies. Furthermore, alveolar bone marrow mesenchymal stem cells were cultured from control and test sockets following biopsy retrieval to evaluate the ability of TAMP bioactive glass scaffolds to recruit host progenitor cells. Results showed that sockets grafted with TAMP bioactive glass scaffolds better preserved height after 3 mo where mesially 57.1% of test cases showed preservation of socket height, compared with 28.6% of control cases. Distally, this was 42.9% of test cases versus none of the control cases. Regarding BMD, the test sides had higher BMD in all 3 sections of the socket, with the greatest reduction in BMD found in the coronal third. Results were not statistically significant. Histologically, sockets grafted with TAMP bioactive glass scaffolds showed a distinct pattern of bone healing characterized by vertical trabeculae and large vascularized marrow spaces with sockets showing corticalization. Volumetric analysis showed a better preservation of socket contour with TAMP bioactive glass scaffolds. TAMP bioactive glass scaffolds appeared to enhance the recruitment of stem cells from the grafted sockets. In conclusion, TAMP scaffolds appear to better preserve alveolar bone following extraction and allow for a more active bone modeling and remodeling process( ClinicalTrials.gov identifier:NCT01878084). Knowledge Transfer statement: The results of this study set the stage for the recommended use of novel biomimetic scaffolds, such as the tailored amorphous multiporous bioactive glass for preservation of the socket following extraction. This can be valuable for patients and clinicians alike when deciding on long-term prosthetic alternatives that not only result in immediate bone preservation but will accommodate the dynamic nature of bone.

l-Methioninase from some Streptomyces isolates I: Isolation, identification of best producers and some properties of the crude enzyme produced.

Among 60 isolates of Streptomyces tested; only 40 isolates were capable to utilize l-methionine as the only source of nitrogen in medium. In addition, 24 of these isolates could grow in medium amended with l-methionine as a source of nitrogen and carbon. Qualitative rapid plate assay test shows the ability of 18 of these isolates to grow with a pink color surrounding their colonial growth, while 6 of these isolates could grow and utilize l-methionine without any pink color around their colonial growth. Quantitative assay test shows the rate of l-methioninase production by all isolates tested. Permeabilization treatment including chemical and physical methods proved that l-methioninase was found to be extracellularly produced. The results also indicate that l-methioninase production was not correlated with growth rate or l-methionine consumption in medium. On the other hand, quantitative assay test shows that these six isolates were l-methioninase negative and failed to produce any amount of l-methioninase. In addition, results also show that isolates No. 4 and No. 60 were the most suitable for l-methioninase production, these two isolates were characterized and identified as Streptomyces sp. DMMMH 4 and Streptomyces sp. MDMMH 60 using 16S rRNA with accession No. in gene bank. Furthermore, optimal conditions for enzyme activity produced by the two isolates were established in relation to temperature, pH, reaction time and type of buffer used and its molarities.

Evaluation of 3D nano-macro porous bioactive glass scaffold for hard tissue engineering.

Recently, nano-macro dual-porous, three-dimensional (3D) glass structures were developed for use as bioscaffolds for hard tissue regeneration, but there have been concerns regarding the interconnectivity and homogeneity of nanopores in the scaffolds, as well as the cytotoxicity of the environment deep inside due to limited fluid access. Therefore, mercury porosimetry, nitrogen absorption, and TEM have been used to characterize nanopore network of the scaffolds. In parallel, viability of MG 63 human osteosarcoma cells seeded on scaffold surface was investigated by fluorescence, confocal and electron microscopy methods. The results show that cells attach, migrate and penetrate inside the glass scaffold with high proliferation and viability rate. Additionally, scaffolds were implanted under the skin of a male New Zealand rabbit for in vivo animal test. Initial observations show the formation of new tissue with blood vessels and collagen fibers deep inside the implanted scaffolds with no obvious inflammatory reaction. Thus, the new nano-macro dual-porous glass structure could be a promising bioscaffold for use in regenerative medicine and tissue engineering for bone regeneration.

Humoral and cellular immune responses of a murine model against Corynebacterium pseudotuberculosis antigens.

Humoral and cellular immune responses were both found to be operative in five groups of Balb/c mice following two subcutaneous inoculations with different antigens of C. pseudotuberculosis. These antigens included toxoid, bacterin, bacterin-toxoid with and without oil adjuvant in addition to the live cell of C. pseudotuberculosis. The responses were assessed, twenty days after the 2nd immunization. Serum antibody levels were determined in an enzyme linked immunosorbent assay (ELISA). Cellular immune responses to C. pseudotuberculosis antigens were measured by detection of gamma interferon (IFN-gamma) in spleen cell culture media of the immunized mice, using commercial mice enzyme immuno-assay kit. All mice were challenged 2 weeks after the last dose of immunization with live C. pseudotuberclosis (2x10(5) CFU/mouse). Protection levels were observed with different degrees between the immunized mice groups.

Reciprocal interaction between seasonal testis and thyroid activity in Zembra Island wild rabbits (Oryctolagus cuniculus): effects of castration, thyroidectomy, temperature, and photoperiod.

The reproductive cycle of wild rabbits (Oryctolagus cuniculus) living in Zembra Island (North Tunisia) is dependent on an external factor, the photoperiod: the gonads are inhibited by long days and stimulated by short days or melatonin implants. Here we studied the role of an internal factor, thyroid hormones and the possible thyroid-gonadal interrelationships, in animals captured on Zembra Island and maintained in natural conditions of photoperiod and temperature. We determined the seasonal profile of the thyroid and testis cycles and investigated the effects of castration and thyroidectomy on the seasonal testosterone and thyroxine cycles. Plasma thyroxine and testosterone levels followed similar, parallel seasonal patterns, with a peak in autumn (October) and low values from January to August. In thyroidectomized animals, plasma testosterone levels, although significantly higher than those in controls (P < 0.001), remained low throughout the 13 mo of the experiment, and no testicular reactivation was observed in the fall. In castrated animals, despite the increase in thyroxine concentration in the 3 mo following castration (P < 0.01), plasma thyroxine levels remained low during the 2 yr of the study. We then investigated the combined effects of long days (16L:8D) and moderately high temperature (25 degrees C) on these two endocrine axes. In constant gonado-inhibiting conditions (16L:8D), whether the temperature was kept constantly high or allowed to fluctuate naturally, no reactivation of the thyroid and testicular axes was observed in the fall. In control animals, the peaks of testosterone and thyroxine concentrations observed in September were larger (P < 0.001) than those in animals subjected to the same natural photoperiod conditions but with constantly high temperature. The lower level of autumnal testis stimulation (P < 0.001) in animals maintained in conditions of constant high temperature (25 degrees C) may be attributed to the low thyroxine levels induced by high temperature. These results clearly confirm that the thyroid and testicular cycles display similar seasonal variations and show that the thyroid and gonadal axes are strictly interdependent. This study provides the first demonstration, for a given species, that the seasonal reactivation of gonad activity is controlled by the thyroid, and thyroid activity is controlled by the gonads.

Comparative toxicity and biochemical responses of certain pesticides to the mature earthworm Aporrectodea caliginosa under laboratory conditions.

This study was conducted to investigate the toxicity of aldicarb, cypermethrin, profenofos, chlorfluazuron, atrazine, and metalaxyl toward mature Aporrectodea caliginosa earthworms. The effects of the LC(25) values of these pesticides on the growth rate in relation to glucose, soluble protein, and activities of glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), acid phosphatase (AcP), and alkaline phosphatase (AIP) were also studied. The results showed that aldicarb was the most toxic of the tested pesticides, followed in order by cypermethrin, profenofos, chlorfluazuron, atrazine, and metalaxyl. A reduction in growth rate was observed in all pesticide-treated worms, which was accompanied by a decrease in soluble protein and an increase in transaminases and phosphatases. Relationships between growth rate, protein content, transaminases, and phosphatases provided strong evidence for the involvement of pesticidal contamination in the biochemical changes in earthworms, which can be used as a bioindicator of soil contamination by pesticides.

Long-day inhibition of reproduction and circadian photogonadosensitivity in Zembra Island wild rabbits (Oryctolagus cuniculus).

We investigated the effects of photoperiod on testicular activity in wild rabbits (Oryctolagus cuniculus) captured on Zembra Island (North Tunisia) and maintained in experimental photoperiodic conditions. Sexually inactive animals were subjected to alternate 3-mo periods of short days (8L:16D) and long days (16L:8D) for 1 yr. Testicular activity increased significantly and then decreased to levels equivalent to or lower than those measured during sexual quiescence after 1 mo of 8L:16D or 16L:8D, respectively. Eight groups of sexually active animals were also exposed to 8L:16D for 60 days. The light phase was divided into two photofractions (7.5 and 0.5 h). The short photofraction interrupted the dark phase 9.5-18.5 h after the beginning of the main photofraction. Testicular activity was inhibited if the short photofraction interrupted the dark phase 12.5 h or more after the beginning of the main photofraction. These results clearly confirm that photoperiod affects reproduction in this species: Short days stimulate reproduction, whereas long days inhibit it. The asymmetric pattern of skeleton photoperiods used demonstrated the existence of a circadian rhythm for photogonadosensitivity, with the photosensitive phase beginning 12.5 h after dawn. In this species, photoperiod length controls both the beginning and the end of the reproductive period. These results differ from those obtained with continental populations of wild rabbits, in which reproduction is inhibited by short day length. This difference may reflect genetic drift linked to the geographic isolation of this population, which is known to have been present on this small island for more than 2000 yr.

Effects of bilateral ganglionectomy and melatonin replacement on seasonal rhythm of testicular activity in Zembra Island wild rabbits (Oryctolagus cuniculus).

This study examined the effects of subcutaneous melatonin implants on testicular activity (testis volume and plasma testosterone) in wild rabbits (Oryctolagus cuniculus) captured on Zembra Island (North Tunisia) and maintained in natural temperature and photoperiod conditions. The period of testicular activity was 2 months longer in intact animals with melatonin implants than in intact animals without melatonin implants. After bilateral superior cervical ganglionectomy, testicular activity was inhibited and no spontaneous recrudescence in gonadal function was observed during the 13 months of the experiment, demonstrating the absence of an endogenous circannual rhythm of reproductive function in this species. Renewed testicular activity was observed 2 months after the insertion of melatonin implants in ganglionectomized animals. These results confirm that testicular activity is stimulated by short days in late autumn and that melatonin reactivates the reproductive axis in this species. This finding is in contrast to that in continental populations of wild rabbits in which reproduction is inhibited by short days or melatonin. These results are discussed in terms of insularity and may reflect the geographical isolation of this population.

[Testicular activity in Orychtolagus cuniculus, a wild rabbit from Zembra island (Tunisia), during short days and long days. The effect of pineal gland deafferentation]. / Activité testiculaire chez Orychtolagus cuniculus, lapin sauvage de l'île de Zembra (Tunisie), en jours courts et en jours longs. Effet de la désafférentation de la pinéale.

Several male wild rabbits from Zembra island were used to determine the effect of the photoperiod and of the cranial sympathectomy on testicular activity. Two groups were used (G1 and G2), including each 4 control rabbits and 5 cranially sympathectomized by removal of the superior cervical ganglia. The G1 animals were reared in natural photoperiod at room temperature; the others (G2) were exposed to alternating three-month periods of short days (8 L-16 D) and long days (16 L-8 D). The changes in the testicular function (testis volume and plasma testosterone levels) were studied during one year. Our data show that: (1) The control animals, reared in natural photoperiod at room temperature, showed a decrease in testicular activity during the winter season (December to February) characterized by short days. However, testis volume and plasma testosterone seemed to be maintained at low levels during the other months of the year. (2) The artificial short days (8 L-16 D) induced an increase of the testis volume and of the plasma testosterone. A significant decrease of these parameters was observed when transferring the animals to long days (16 L-8 D). (3) The deafferentation of the pineal body by bilateral superior cervical gangliectomy blocked the testicular activity either when the animals were maintained in natural photoperiod or transferred from (8 L-16 D) to (16 L-8 D). Thus the testicular activity of wild rabbits from Zembra island is controlled by the photoperiod. Light action on the pineal is carried via the superior cervical sympathetic ganglia.

Study of noise, hearing impairment and hypertension in Egypt.

This study included 295 workers of Assiut Generation Station (Upper Egypt). Two hundred and twenty-one of the workers were exposed to different levels of noise (80 to 107 dBA) and the remaining 74 were used as a control group. There were no significant differences in risk factors viz age, duration of work, body mass index, weight, height, smoking, and previous work as determined by a questionnaire. The relationship between occupational exposure to noise, the degree of hearing loss and hypertension was determined. The results showed that there were statistically significant differences between the average hearing threshold levels of the two groups (P<0.01) which were more in those workers exposed to noise than in the control group. The mean systolic and diastolic blood pressures were also statistically significantly different in the two groups (P<0.001) and they were positively correlated (P<0.001) to the percentage of impairment of the whole body at 74 and 6 kHz, and hearing disability at 0.5, 1, 2 and 3 kHz. Stepwise multiple regression analysis revealed that age, noise level and body weight could each be used as a predictor of hypertension. A predictive formula was derived between the amount of hearing loss and blood pressure in the subjects exposed to occupational noise.

Slow negative evoked potentials in the rhesus monkey (Macaca mulatta): myogenic versus neurogenic influences.

The influence of myogenic activity on the generation of slow negative evoked potentials (SN10) to octave, toneburst stimuli (0.5-2 Hz) was investigated in 5 rhesus monkeys (M. mulatta) by comparing responses obtained prior to and during total paralysis induced with curare. The SN10 could be easily elicited during paralysis, regardless of stimulus intensity, rate, or frequency. During paralysis, there were no systematic changes in either response latency or amplitude; variability in latency was less than 10% and changes in response amplitude were within 30%. These findings suggest that the myogenic contribution to the SN10 response is negligible and that this response is of neurogenic origin in the rhesus monkey.

Maturation of the auditory brain stem response in rhesus monkeys (Macaca mulatta).

To document the maturational changes in the auditory brain stem response (ABR) of the rhesus monkey, longitudinal and cross-sectional data were collected on a panel of 31 animals during the first year of life. Each ABR test consisted of averaging 2048 responses to click stimuli delivered at a rate of 21 clicks/sec and elicited at 60, 40, 20 and 10 dB HL intensities in accordance with procedures described previously. The morphology of the ABR wave form recorded at birth was similar to that at 12 months of age and the latencies of the component waves decreased exponentially over this period. The magnitude of decrease in latency was greatest for wave IV and least for wave I. The regression lines for the log of the latencies of 3 waves on age were computed for 3 animals followed longitudinally and for the cross-sectional data set. The slopes of these regression lines were different among animals, indicating differing rates of maturation. However, these slopes were identical for the component waves of any one animal, suggesting that the rate of maturation was constant over the auditory pathway. These changes were similar in pattern to those reported for human data and suggest that the rhesus monkey may serve as an appropriate model of auditory development in man.

Auditory brain stem responses in rhesus monkey with otitis media with effusion.

Auditory brain stem response (ABR) tests were conducted on 17 anesthetized juvenile rhesus monkeys. Recordings were obtained for 13 control ears without otitis media with effusion (OME) and seven experimental ears with OME. The results demonstrated an increase in response latencies for the experimental ears with OME at each of four stimulus presentation levels (80, 60, 40, and 20 dB hearing level). Interwave latencies were the same for both groups of ears. The results suggest an average 25-dB peripheral loss of predominantly middle ear origin associated with OME. The ABR appeared to be a viable technique for documenting auditory impairment associated with OME in this nonhuman primate model.

Anomalous middle ear gas absorption in a non-human primate model of cleft palate.

Following surgical clefting of the palates of nine Rhesus monkeys (Macaca mulatta), daily recordings of the middle ear pressure by tympanometry have shown fluctuations between high positive and negative values. High positive middle ear pressures were recorded during the recovery from otitis media, and it was suggested that these pressures were the result of a learned or reflexive autoinflation of the middle ear cavity. To test this hypothesis, animals presenting high positive middle ear pressures were anesthetized with sodium pentobarbital, and serial tympanograms were obtained at 5-minute intervals for a period of four hours. The results showed a substantial and rapid decrease in middle ear pressure following anesthesia (200 to 400 mm H2O). These findings were compared to those of similar experiments in normal animals, with near zero resting middle ear pressures or following air and oxygen politzerizations. The changes in middle ear pressure of cleft palate animals were significantly greater than those recorded for normal animals with near zero resting middle ear pressure and were essentially the same as those recorded for normal animals following air politzerization. These data suggest that abnormally high positive middle ear pressures are the result of an introduced bolus of air. This mechanism may serve as a means of ventilating the middle ear cleft in lieu of a debilitated active dilatory mechanism, and as such, may aid in the resolution of the middle ear effusion.

Morphology of the middle ear in the rhesus monkey (Macaca mulatta).

The purpose of this study was to provide a description of the morphology of the middle ear and related structures in the rhesus monkey, Macaca mulatta. From these descriptions, it can be seen that except for relative size differences, the middle ear system of the rhesus monkey bears close resemblance to that of man. The basic architecture is the same, thereby providing an anatomic foundation for the observed similarities in function [Cantekin et al,, 1981]. The few differences between the two systems can be summarized as follow: (1) The angle of inclination of the medial wall on the parasagittal plane is more acute in the rhesus monkey than in man. (2) The shape of the tympanic membrane in the monkey is almost circular compared to the irregular oval shape in man. (3) Differences in the shape of the ossicles as well as differences of relative measurements and angles between the parts of the ossicles were observed. (4) A major difference involves the pneumatic system and most prominently, the absence of a definite mastoid process in the monkey. However, the mastoid portion of the temporal bone is still very cellular in the majority of the specimens and communicates with the middle ear cavity through a well-defined mastoid antrum. The well-developed and extremely cellular petrous bulla in the monkey is absent in man.