Creation of an injectable in situ gelling native extracellular matrix for nucleus pulposus tissue engineering.

BACKGROUND CONTEXT: Disc degeneration is the leading cause of low back pain and is often characterized by a loss of disc height, resulting from cleavage of chondroitin sulfate proteoglycans (CSPGs) present in the nucleus pulposus. Intact CSPGs are critical to water retention and maintenance of the nucleus osmotic pressure. Decellularization of healthy nucleus pulposus tissue has the potential to serve as an ideal matrix for tissue engineering of the disc because of the presence of native disc proteins and CSPGs. Injectable in situ gelling matrices are the most viable therapeutic option to prevent damage to the anulus fibrosus and future disc degeneration. PURPOSE: The purpose of this research was to create a gentle decellularization method for use on healthy nucleus pulposus tissue explants and to develop an injectable formulation of this matrix to enable therapeutic use without substantial tissue disruption. STUDY DESIGN: Porcine nuclei pulposi were isolated, decellularized, and solubilized. Samples were assessed to determine the degree of cell removal, matrix maintenance, gelation ability, cytotoxic residuals, and native cell viability. METHODS: Nuclei pulposi were decellularized using serial detergent, buffer, and enzyme treatments. Decellularized nuclei pulposi were solubilized, neutralized, and buffered. The efficacy of decellularization was assessed by quantifying DNA removal and matrix preservation. An elution study was performed to confirm removal of cytotoxic residuals. Gelation kinetics and injectability were quantified. Long-term in vitro experiments were performed with nucleus pulposus cells to ensure cell viability and native matrix production within the injectable decellularized nucleus pulposus matrices. RESULTS: This work resulted in the creation of a robust acellular matrix (>96% DNA removal) with highly preserved sulfated glycosaminoglycans (>47%), and collagen content and microstructure similar to native nucleus pulposus, indicating preservation of disc components. Furthermore, it was possible to create an injectable formulation that gelled in situ within 45 minutes and formed fibrillar collagen with similar diameters to native nucleus pulposus. The processing did not result in any remaining cytotoxic residuals. Solubilized decellularized nucleus pulposus samples seeded with nucleus pulposus cells maintained robust viability (>89%) up to 21 days of culture in vitro, with morphology similar to native nucleus pulposus cells, and exhibited significantly enhanced sulfated glycosaminoglycans production over 21 days. CONCLUSIONS: A gentle decellularization of porcine nucleus pulposus followed by solubilization enabled the creation of an injectable tissue-specific matrix that is well tolerated in vitro by nucleus pulposus cells. These matrices have the potential to be used as a minimally invasive nucleus pulposus therapeutic to restore disc height.

Indications for caesarean sections at ≥34 weeks among nulliparous women and differential composite maternal and neonatal morbidity.

OBJECTIVE: To compare composite maternal and neonatal morbidities (CMM, CNM) among nulliparous women with primary indications for caesarean section (CS) as acute clinical emergency (group I; ACE), non-reassuring fetal heart rate (group II) and arrest disorder (group III). DESIGN: A multicentre prospective study. SETTING: Nineteen academic centres in the USA, with deliveries in 1999-2002. POPULATION: Nulliparous women (n = 9829) that had CS. METHODS: Nulliparous women undergoing CS for three categories of indications were compared using logistic regression model, adjusted for five variables. MAIN OUTCOME MEASURES: CMM was defined as the presence of any of the following: intrapartum or postpartum transfusion, uterine rupture, hysterectomy, cystotomy, ureteral or bowel injury or death; CNM was defined as the presence of any of the following: umbilical arterial pH <7.00, neonatal seizure, cardiac, hepatic, renal dysfunction, hypoxic ischaemic encephalopathy or neonatal death. RESULTS: The primary reasons for CS were ACE in 1% (group I, n = 114) non-reassuring FHR in 29% (group II; n = 2822) and failed induction/dystocia in the remaining 70% (group III; n = 6893). The overall risks of CMM and CNM were 2.5% (95% confidence intervals, CI, 2.2-2.8%) and 1.9% (95% CI 1.7-2.2), respectively. The risk of CMM was higher in group I than in group II (RR 4.1, 95% CI 3.1, 5.3), and group III (RR 3.2, 95% CI 2.7, 3.7). The risk of CNM was also higher in group I than in group II (RR 2.8, 95% CI 2.3, 3.4) and group III (RR 14.1, 95% CI 10.7, 18.7). CONCLUSIONS: Nulliparous women who have acute clinically emergent caesarean sections are at the highest risks of both composite maternal and neonatal morbidity and mortality.

Tongue-Supported Human-Computer Interaction systems: a review.

The tongue can substitute human sensory systems and has been used as a medium of input to help impaired patients communicate with the world. Innovative techniques have been employed to realize tongue movement, sense its position and exploit tongue dexterity, in order to achieve Tongue Supported Human Computer Interaction (TSHCI). This paper examines various approaches of using tongue dexterousness in TSHCI systems and introduces two infrared signal supported minimally-invasive TSHCI systems developed at Curtin University. Methods of sensing tongue movement and position are especially discussed and depending on the employed methods, TSHCI systems are categorized as either invasive or minimally-invasive. A set of system usability criteria is proposed to help build more effective TSHCI systems in future.

Genetic diversity among Zygophyllum (Zygophyllaceae) populations based on RAPD analysis.

Zygophyllum species are succulent plants that are drought resistant and/or salt tolerant, growing under severe, dry climatic conditions. Despite their importance and abundance in the Mediterranean and Middle East regions, there is little information concerning molecular variations among species of this genus. Genetic diversity was assessed, using RAPD primers, of 12 populations of Z. coccineum, Z. album and Z. aegyptium collected from various locations in Egypt and Saudi Arabia. Yong leaves were used for DNA extraction. Genetic distances were calculated using Nei's method. A dendrogram was constructed based on the similarity data matrix by unweighted pair group method using arithmetic averages cluster analysis. Analysis with RAPD markers revealed genetic variation between and within populations of Zygophyllum. Zygophyllum coccineum showed higher levels of genetic variation and more unique alleles than the other species.

A burn prevention program as a long-term investment: trends in burn injuries among Jews and Bedouin children in Israel.

In order to broaden our long-term intervention efforts in elementary schools in Israel (underway since 1988) and to set priorities for further population-specific actions, we compared the pattern of burn injuries among two age groups (0-4; 5-14) of two ethnic groups of Jews and Bedouins admitted to a regional hospital between 1986 and 1995 (n = 1050). The findings indicated a significant downward trend, though somewhat nonlinear, in burn admissions among the older age groups. A relatively less favorable trend was observed for the younger age groups. Consistently across years, burn rates in the younger group of Bedouin children were the highest. For the 10-year period, a significant season by ethnic group variation in burn admissions was observed, with a peak in the spring and in the wintertime for the Jews and Bedouins, respectively. A significant trend of decrease, mostly among older children, in average lengths of hospital stay, was also evident. Yet, regardless of age group and across years, Bedouin children stayed longer in the hospital than Jewish children. The overall leading causes of injury (for 1992-1995) were hot liquids (69%), fire (17%), chemicals (9.5%) and contact (2%). In our view, there is a need to address at-risk populations through environmental, community and family-oriented interventions and to venture beyond the pathogenic factors to the investigation of the salutary factors of health under diverse life conditions.

The effect of eugenol-containing temporary cement on the bond strength of two resin composite core materials to dentin.

PURPOSE: This study investigated the effect of eugenol-containing temporary cement on the bond strength of two resin composite core materials (FluoroCore and Ti-Core) to dentin. MATERIALS AND METHODS: Dentin was exposed in three groups of extracted teeth (20 specimens each). In group one, dentin was covered with eugenol-containing temporary cement; the second group was covered with eugenol-free temporary cement; and the third group was left uncovered and served as a control group. All specimens were stored for 1 week at 37 degrees C and 100% humidity. The dentin surfaces were cleaned and treated using the GLUMA adhesive system, followed by placement of composite core build-ups. Debonding of the core material was accomplished using the Accuforce Elite test system. RESULTS: There was a significant reduction in bond strength for the specimens covered with eugenol temporary cement (p < .0001), but no significant difference was found between the control group and the group treated with eugenol-free temporary cement. Bond strength of the Ti-Core material to dentin was significantly higher than that of FluoroCore (p < .0001). CONCLUSION: Pretreatment of the dentin with eugenol-based temporary cement adversely affects the bond strength of resin composite core material to dentin.

Designs of bond strength tests for metal-ceramic complexes: review of the literature.

Despite the popularity of metal-ceramic restorations, the bonding mechanism remains the subject of theoretical discussion. Different experimental designs to evaluate bond strengths at the metal-ceramic interface are described. The effects of various stresses with each design are also discussed. A predictive experimental design should minimize variables and result in the least residual interfacial stresses. Dentists and dental technicians should benefit from comparisons of existing tests, and the discussion encourages introduction of more comprehensive approaches.

The effect of fluoride treatments on glazed and polished ceramic surfaces.

A scanning electron microscope (SEM) Study was conducted to evaluate the micromorphology of glazed and polished ceramic restoration surfaces after treatment with different types of fluorides with different concentrations and acidity. This study showed that glazed ceramic surfaces appeared to be smoother and more resistant to fluoride agents than polished ceramic surfaces. Fluoride agents with a lower pH (more acidic) and higher in fluoride concentration caused more surface damage to porcelain. Therefore, it is recommended to use a neutral fluoride agent with low fluoride concentration. If the ceramic restoration is to be polished after glazing due to clinical adjustment, it is advisable to reglaze it particularly before fluoride application.

Marginal castability of two different materials (a comparative study).

Achieving a clinically acceptable margin is a conspicuous objective to any practicing dentist. The main concern is the space existing between the margin of the prepared tooth and that of the final restoration. Marginal fit has been measured and evaluated in a variety of methods., and a gap of approximately 50 microns is usually considered acceptable. While inlay wax is the material commonly used in the wax-up stage when fabricating crowns and bridges, Duralay (methylmethacrylate) is a material widely used nowadays in the field of fixed prosthodontics. Due to the ease of using this material intra-orally to form margins, an attempt is made to compare the castability of margins made out of inlay wax to the ones made out of Duralay.

Familial pericentric inversion of chromosome 13, 46,XX,inv (13)(p13;q11): a new variant.

A 10-year-old female with right oblique inguinal hernia was investigated to exclude an XY karyotype. Chromosome analysis of peripheral blood showed 46,XX,inv(13)(p13;q11). In vitro aneuploidy was observed in two cells: a) 46,XX,inv(13), inv(13); b) 47,XX, +inv(13). Her father and three sisters were carriers for inv(13). Herein the authors review briefly familial inv(13)'s and report a new variant involving breakpoints (p13;q11).

A qualitative study for the bond and color of ceramometals. Part II.

Many dentists, porcelain manufacturers, and dental technicians empirically state that repeated firings tend to bleach out or alter the original shade of porcelain. This investigation used a sophisticated colorimeter to resolve the controversy. The effect of temperature rise and number of firings had varying effects on color relative to brand of porcelain and specific alloy.

A qualitative study for the bond and color of ceramometals. Part I.

A shear testing method was devised to study and evaluate the effect of various and repeated firing cycles, types of alloy, and brand of porcelain relative to the color and bond strength of ceramometal complexes specifically at the opaque porcelain-metal interface and the opaque-body porcelain juncture. Two alloys and two porcelain brands were chosen on the basis of their widespread clinical use and the marked contrast between them. An increase of the firing temperature significantly raised the bond strength for all alloy-porcelain combinations.

Mosaicism 45,X/46,X, t dic(Xp:Xp) in a girl with short stature.

An eight-year-old girl with marked short stature and no apparent stigmata of Turner syndrome was investigated. Clinical features include bilateral epicanthic folds, frontal bossing, prominent ears and normal intelligence. Ultrasound scanning revealed an apparently normal vagina, streak ovaries and no uterus. Bone age was normal. Karyotype analysis of peripheral blood lymphocytes showed mos 45,X/46,X tdic(Xp:Xp) in the ratio 66:34, respectively. In addition, three cells with different abnormal X chromosomes were present which possibly originated from a 46,XX clone. Replication of the duplicated X chromosome was consistently late and symmetrical. Buccal smear confirmation of the karyotype showed Barr body negative in 90% and large or bipartite in 10% of the cells. Karyotypes of the parents were normal. The clinical manifestations in cases of Xp deletion due to terminal rearrangement associated with or without a 45,X cell line are discussed.

Familial manic-depressive illness with deleted short arm of chromosome 21: coincidental or causal?

A 35-year-old Arab lady and her mother, both with bipolar manic-depressive illness and 46,XX,21p-(pcen----pter), are reported. The clinical significance of this association is considered.

A shear test for the bond strength of ceramometals.

An innovative shear-testing method was introduced to study the effect of firing temperature, type of metal, and surface texture on the bond strength of the ceramometals. Two common ceramic/metal alloys were used: Olympia, a precious alloy, and Talladium, a base alloy. A Ceramco II Paint-O-Pake opaque was selected for the study. Each porcelain alloy was prepared in a similar manner before porcelain application to achieve uniform surfaces. A separate category of base alloy samples was subjected to etching after sandblasting. Each category was then divided into two groups. Opaque porcelain was fired according to the manufacturer's instructions in one group and 65 degrees F higher in the other. The bond strengths were compared by statistical analysis and post-tested samples were evaluated visually and microscopically with a scanning electron microscope.