Role of the melanocortin-4 receptor in metabolic rate and food intake in mice

We evaluated the role of the melanocortin-4 receptor (MC-4R) in the control of metabolic rate and food intake in mice. Intraperitoneal administration of the non-selective MC-R agonist melanotan II (MT-II; a cyclic heptapeptide) increases metabolic rate in wildtype mice, while MC-4R knockout mice are insensitive to the effects of MT-II on metabolic rate. MC-4R knockout mice are also insensitive to the effects of MT-II on reducing food intake. We conclude that MC-4R can mediate control of both metabolic rate and food intake in mice. We infer that a role for MC-3R in mediating the acute effects of MT-II on basal metabolic rate and food intake in wildtype mice seems limited.

Identification and analysis of the sap genes from Vibrio fischeri belonging to the ATP-binding cassette gene family required for peptide transport and resistance to antimicrobial peptides

Partial nucleotide sequences of the sapD and sapF genes of the sap operon (GenBank Accession No. AF178651) from Vibrio fischeri ATCC 7744 have been determined, and the peptide transport system of ATP-binding proteins SapD and SapF encoded by the genes have been deduced. Alignment and comparison of the Sap proteins of V. fischeri, Escherichia coli, Salmonella typhimurium, and Haemophilus influenzae Rd show that these proteins are homologous. The sap operon residing in the genome enables V. fischeri to transport peptides and resist antimicrobial peptides. Nucleotide sequence and functional analyses confirm that the specific regulatory-region-like sequence R&R* that resides inside the sapD gene and before the sapF gene functions in gene expression and regulation; also, it is regulated by the LuxR-AI complex of the V. fischeri lux regulon. The putative upstream activator binding sequences SigmaUASI, SigmaUASII, SigmaUASIII TGTCGACTTGGGCCTCGCTGTCCGTATGCACA (72nd to 103rd bp), TGTCCGTATGCACA (90th to 103rd bp), and TGTTCAAGTACCAGAAAGACA (111st to 133rd bp) in the R&R* sequence, which are similar to the two-component regulator binding sequence TGT-N(8-12)-ACA and the LuxR-AI binding sequence ACCTGTAGGATCGTACAGGT in the regulatory region of the V. fischeri lux regulon, might be the specific sequences recognized by the LuxR-AI complex for enhancement.

Growth performance and digestive and metabolic responses of gilts penned individually or in groups of four

Two experiments were conducted to identify factors involved in the growth retardation of pigs housed in groups. In each experiment, 60 gilts were allotted to two treatments in a randomized complete block design. Twelve gilts were penned individually with one feeder, one waterer, and a space allowance of 1.5 m2 per pen. Forty-eight gilts were allocated to 12 groups of four and penned together with four feeders, four waterers, and a space allowance of 6 m2 per pen. In Exp. 1 there were 60 growing gilts (initial and final BW of 17.9 and 50.8 kg, respectively), and in Exp. 2 there were 60 finishing gilts (initial and final BW of 46.0 and 118.3 kg, respectively). In Exp. 1 there was a trend (P < .10) toward greater final BW, ADG, and average backfat thickness of gilts penned individually. Apparent digestibilities of DM, CP, and energy tended (P < .10) to be greater and plasma NEFA concentrations were lower (P < .05) for gilts penned individually. Plasma concentrations of urea and glucose were similar between treatments. In Exp. 2, ADG was greater (P < .05) and there was a trend (P < .10) for greater final weight, ADFI, loin weight, and primal cut weight of gilts penned individually. Apparent digestibilities of DM, CP, and energy and the plasma concentrations of urea, glucose, and NEFA were similar in both treatments. In summary, growing gilts penned four per group had reductions in daily gain, backfat thickness, and apparent digestibilities of DM, CP, and energy and increases in plasma NEFA concentrations. Finishing gilts penned four per group had reductions in daily gain and feed intake with no changes in apparent nutrient digestibilities or plasma metabolite concentrations compared to individually penned gilts.

Antidiabetic effect of Oenanthe javanica flavone

AIM

To study the antidiabetic effect of Oenanthe javanica flavone (OjF).

METHODS

Mice were injected i.v. with alloxan 90 mg.kg-1 to induce diabetes. Blood glucose, serum lipid, and pancreatic amylase were determined with Automatic Biochemistry Analysor. Serum insulin was determined by radioimmunoassay. The pancreas and islets were examined under microscope.

RESULTS

OjF 200 mg.kg-1 reduced the blood glucose in normal mice from 0.5 to 6 h after a single administration ig. OjF 200 and 400 mg.kg-1 ig daily for 10 d decreased the blood glucose in alloxan-induced hyperglycemic mice (P < 0.05, P < 0.01). OjF promoted the release of insulin both in normal and in diabetic mice. OjF decreased serum triglyceride and raised the lowered pancreatic amylases in diabetic mice (P < 0.01, P < 0.01). The islet-injured changes of OjF-treated group were similar to those of control in histology examination, but to a lesser degree.

CONCLUSION

OjF possessed the hypoglycemic and hypotriglyceride actions, mainly concerned with promoting release of insulin from B-cells in islets of langerhans.

Structure-activity relationship studies on 1-[2-(4-Phenylphenoxy)ethyl]pyrrolidine (SC-22716), a potent inhibitor of leukotriene A(4) (LTA(4)) hydrolase

Leukotriene B(4) (LTB(4)) is a pro-inflammatory mediator that has been implicated in the pathogenesis of a number of diseases including inflammatory bowel disease (IBD) and psoriasis. Since the action of LTA(4) hydrolase is the rate-limiting step for LTB(4) production, this enzyme represents an attractive pharmacological target for the suppression of LTB(4) production. From an in-house screening program, SC-22716 (1, 1-[2-(4-phenylphenoxy)ethyl]pyrrolidine) was identified as a potent inhibitor of LTA(4) hydrolase. Structure-activity relationship (SAR) studies around this structural class resulted in the identification of a number of novel, potent inhibitors of LTA(4) hydrolase, several of which demonstrated good oral activity in a mouse ex vivo whole blood assay.

Reversible, nanometer-scale conductance transitions in an organic complex

Reversible conductance transitions are demonstrated on the molecular scale in a complex of 3-nitrobenzal malononitrile and 1, 4-phenylenediamine, by application of local electric field pulses. Both macroscopic and local current-voltage (I/V) measurements show similar electrical bistability behavior. The mechanism of the electrical bistability is discussed.

Three-dimensional ultrasound in the assessment of fetal cerebellar transverse and antero-posterior diameters

Fetal cerebellum scanning by prenatal ultrasound (US) is very important for early detection of fetal central-nervous-system anomaly, as well as for the determination of gestational age (GA). Due to the small organ size and the unique shape of the fetal cerebellum (CL), accurate measurement of the dimensions of CL by two-dimensional (2-D) US is not easy if the appropriate plane cannot be reached. With the advent of three-dimensional (3-D) US, the disadvantages of 2-D US in assessing the fetal CL dimensions can be avoided. The purpose of this study was to assess the fetal cerebellar transverse diameter (CTD) and cerebellar antero-posterior diameter (CAD) using 3-D US. First, we compared the reproducibility of 2-D and 3-D US on the assessment of fetal cerebellar dimensions. Second, we prospectively measured CTD and CAD in 223 healthy fetuses using a cross-sectional design with an attempt to establish the normal growth charts of fetal CL. Our results showed 3-D US is superior to 2-D US in the reproducibility test of fetal cerebellar dimensions. In addition, with GA as the dependent variable, polynomial regression analysis showed that the best-fit equations for both CTD vs. GA and CAD vs. GA were the first-order. The best-fit predictive equation of GA by CTD was GA (week) = 9.0281 + 0. 58533 x CTD (mm) (r = 0.95, n = 223, SE = 1.82 weeks, p < 0.0001), and the best-fit predictive equation of GA by CAD was GA (week) = 10. 855 + 1.1672 x CAD (mm) (r = 0.82, n = 223, SE = 3.41 weeks, p < 0. 0001). Furthermore, all the correlation coefficients of CTD or CAD vs. the common fetal growth indexes were also highly significant (all p < 0.0001). In conclusion, our data of fetal CL dimensions assessed by 3-D US may serve as a useful reference in assessing fetal CL growth, dating GA or detecting fetal CL anomalies.

Simultaneous determination of polycarboxylic acids by capillary electrophoresis with a copper electrode

The simultaneous determination of polycarboxylic acids including oxalic acid, citric acid, malonic acid, malic acid, tartaric acid, aspartic acid and glutamic acid was achieved by capillary electrophoresis with a copper disk electrode (d = 200 microm). In the system. 0.2 mmol/l cetylpridinium bromide (CPB) was used as an electroosmotic flow (EOF) modifier to reverse the direction of EOF. The effects of the solution pH and CPB concentration on separation were evaluated to achieve the optimum separation conditions. At the working potential of +0.14 V (vs. saturated calomel electrode), the calibration curves for all polycarboxylic acids studied were linear with 2 approximately 3-orders of magnitude and all the detection limits (S/N = 3) were below 15 fmol except malonic acid. Furthermore, the oxalic and citric acids in urine were successfully separated and determined with high sensitivity.

Seroprevalence of Coxiella burnetii infection in southern Taiwan

BACKGROUND AND PURPOSE

The emergence of infection with Coxiella burnetii, the causative organism of Q fever, has been only recently recognized in Taiwan. Several cases of acute Q fever infection have been described, but the prevalence of antibodies to C. burnetii in the general population in Taiwan has not been reported. Thus, we studied the seroprevalence of C. burnetii infection in southern Taiwan.

METHODS

We conducted a retrospective serosurvey to examine the prevalence of C. burnetii infection among subjects admitted to a rural hospital in Taiwan for various reasons, and among presumably healthy attendees of a routine physical examination clinic of an urban public hospital. The diagnosis of C. burnetii infection required the presence of antibodies to both phase I and II antigens (titer > or = 1:16) or only to phase II antigens (titer > or = 1:256), as detected by indirect immunofluorescence assay.

RESULTS

The prevalence of C. burnetii infection was 4.2% in both the in-patient (15/357) and physical examination participant (11/259) populations. None of these subjects had signs compatible with acute Q fever (febrile illness within the past 3 months). The antibody prevalence rate was higher in males than in females, and peaked in persons aged 61 to 70 years.

CONCLUSIONS

These data suggest that C. burnetii infection is not rare in southern Taiwan and does not cause clinical symptoms in all infected patients.

Mechanical properties and wear behavior of light-cured packable composite resins

OBJECTIVES

Determination of flexural strength, flexural modulus, fracture toughness and wear resistance of three packable composites (Solitaire, Surefil, ALERT) and a packable ormocer (Definite) in comparison with an advanced hybrid composite (Tetric Ceram) and an ion-releasing composite (Ariston pHc).

METHODS

Flexural strength, flexural modulus and fracture toughness of each material were determined in three-point bending (each test n = 10). Single-edge notched-bend specimens were used to evaluate the fracture toughness (K1C). Wear of the materials (n = 8) was determined in a pin-on-block-design with a spherical Degusit antagonist at 50 N vertical load and quantified by a replica technique using a 3D-laser scanner. Replicas were made after 6000, 10,000, 30,000 and 50,000 load cycles. The mean wear rate (MWR (micron 3 cycle-1)) was obtained by a linear regression analysis in the steady-state of the time-wear-curve. All results were statistically analyzed with ANOVA and post hoc Tukey HSD tests (p < 0.05).

RESULTS

ALERT exhibited the highest flexural modulus (12.5 +/- 2.1 GPa) and K1C (2.3 +/- 0.2 MN m-3/2), but the lowest wear resistance (8275 micron 3 cycle-1). Solitaire presented the highest wear resistance (1591 micron 3 cycle-1), but significantly lower flexural strength (81.6 +/- 10.0 MPa), flexural modulus (4.4 +/- 0.3 GPa), and K1C (1.4 +/- 0.2 MN m-3/2) than all other materials. Surefil revealed a significantly higher flexural modulus (9.3 +/- 0.9 GPa) and wear resistance (3028 micron 3 cycle-1) than Tetric Ceram (6.8 +/- 0.5 GPa; 5417 micron 3 cycle-1) and Ariston pHc (7.3 +/- 0.8 GPa; 7194 micron 3 cycle-1).

SIGNIFICANCE

The tested packable composite resins differed significantly in their mechanical properties. This study suggested that fracture and wear behavior of the composite resins are highly influenced by the filler system. Overall, Surefil demonstrated good fracture mechanics parameters and a low wear rate.

Layer dynamics of freely standing smectic-A films

The dynamics of freely standing thermotropic smectic-A films are studied in the isothermal, incompressible limit via a continuous hydrodynamic description. The role of permeation in the films, the structure of the hydrodynamic normal modes, and the form of the autocorrelation functions for the smectic layer and order-parameter fluctuations are discussed. We find two characteristic lengths l(d)=sqrt[alphad/B] and l(c)=sqrt[eta(2)(3)d/8rhoalpha] associated with the dynamic behavior of the system, where alpha is the surface tension, d is the film thickness, B is the elastic constant for layer compression, eta(3) is the layer sliding viscosity, and rho is the density of the liquid crystal. The crossover from filmlike to bulklike behavior is controlled by l(d) alone; the crossover from overdamped to underdamped dynamics when the in-plane length scale is large compared to l(d) is controlled by l(c) alone.

Levothyroxine suppression of thyroglobulin in patients with differentiated thyroid carcinoma

For patients with differentiated thyroid carcinoma, the appropriate degree of TSH suppression by levothyroxine (L-T4) is still unknown. To find the target level of TSH suppression, we analyzed the relationship between the degree of TSH suppression determined by third generation assay and thyroglobulin (Tg) response during the titration of the dosage of L-T4. Ninety-two patients with differentiated thyroid carcinoma (19 males and 73 females; age, 40.5+/-13.5, mean +/- SD) were included. All of the recruited patients had near-total thyroidectomy, 30-150 mCi 131I thyroid ablation, and negative Tg autoantibodies. They were classified into 3 groups. Group A was composed of 25 patients with local or distant relapse. Group B was composed of 12 patients without clinically detectable relapse, but Tg levels either above 2 ng/mL under L-T4 suppression or above 3 ng/mL off L-T4 therapy. Group C included 55 patients who had no active disease and Tg levels below 2 and 3 ng/mL during and off L-T4 suppression, respectively. Serum TSH and Tg were measured simultaneously at the end of 8-12 weeks of a certain dose of L-T4 therapy during dosage titration and also after withdrawal of L-T4 for 4-6 weeks for the total body scan. Wilcoxon signed ranks test was used to compare paired samples of Tg, and Spearman rank correlation was used to determine the correlation of relative changes in TSH to changes in Tg calculated by individual. The results showed that 1) Tg levels were significantly higher during the period off L-T4 therapy than on L-T4, therapy in all 3 groups (P < 0.01); 2) during L-T4, therapy, within the same treatment course, mean Tg levels were higher when TSH levels were normal than when TSH levels were suppressed, statistically significant in group A (P = 0.001), nonsignificant in group B (P = 0.09), and nonsignificant in group C (P = 0.30); and 3) when TSH was suppressed below normal, there was no correlation between the relative changes in TSH and Tg by individual in all 3 groups (P > 0.05). The data suggest a stratified postoperative thyroid hormone management of patients with differentiated thyroid carcinoma. TSH should be lowered to below normal in patients with active disease. If patients are clinically disease free with Tg levels below 2 ng/mL, TSH can be kept within the normal range. For the most controversial group B patients, it is recommended that the TSH be suppressed and be closely followed up.

Bond strength of a compomer to dentin under various surface conditions

This study determined the influence of different dentin pretreatments on the shear bond strength of an adhesive system and corresponding compomer material. One hundred and twenty freshly extracted human molars were ground with wet SiC paper to expose flat oral/buccal surfaces of superficial dentin. The teeth were assigned to 12 treatment groups (n = 10) based on dentin surface finish (600-grit SiC vs. air abrasion vs. 40 microns diamond bur), surface conditioning (acid etching vs. no etching), and moisture content of the dentin (moist vs. dry). Cylinders of Compoglass F compomer were bonded to the dentin with Syntac Single-Component. After 24-h storage in distilled water, the specimens were debonded in shear mode. Bond strengths in MPa (SD) were calculated and bonding sites were analyzed for the mode of failure. Three-way ANOVA revealed significantly higher bond strength values for acid etched specimens (P = 0.001). Moisture content of the dentin surface (P = 0.614) and mechanical surface finish (P = 0.367) had no significant influence on the results. Debonding in unetched groups ranged from 94 to 100% adhesively. Acid etched groups showed adhesive failures ranging from 56 to 100%. To obtain a more reliable bond it is recommended that dentin is acid etched prior to the bonding of a compomer.

The effect of infusion of urea into the vena cava on feed intake of finishing gilts

Three experiments were conducted to evaluate the relationship between feed intake and plasma urea concentration. In Exp. 1, six gilts (BW 53 kg) with catheters in their venae cavae were used in a 5x5+1 Latin square design to determine the amount of infused urea needed to mimic the plasma urea concentration of pigs fed a 25% CP diet. Five gilts were fed a 16% CP corn-soybean meal diet and were infused continuously with either saline or one of four doses of urea (6, 12, 18, and 24 g/d) during each of five periods (12 h/period). Between periods, infusions were stopped for 36 h. The sixth pig was fed a 25% CP diet and infused with saline during each of the experimental periods. Venous blood samples were obtained at 1-h intervals starting 1 h before infusion. As expected, plasma urea concentration increased with increasing amount of urea infused. A daily infusion of 24 g of urea resulted in a plasma urea concentration similar to that of the pig fed the 25% CP diet with saline infusion. In Exp. 2, 12 gilts (BW 60 kg) were used in a crossover design. Pigs received a 16% CP diet and a different treatment (saline or 24 or 30 g/d of urea) in each of three infusion periods. Each infusion period lasted 2 wk. Infusions were stopped for 2 d between periods. Blood samples were obtained before infusion and daily after infusions started. Feeders were weighed daily to determine ADFI. Experiment 3 was similar to Exp. 2, except that only two treatments (saline and 30 g/d of urea) were used. Data from Exp. 2 and 3 were combined for statistical analysis. Plasma urea concentration increased linearly (P<.001) with increasing amount of urea infused. Overall, there was a trend (P<.10) for urea infusion to decrease ADFI, and pigs infused with 30 g/d consumed less (P<.05) feed than pigs infused with saline. Therefore, plasma urea concentration may play a role in regulating feed intake in gilts consuming excess protein.

[Relatedness of Shigella sonnei isolates from six outbreaks in Tao-Yuan area, Taiwan]

Between November 1995 and January 1996, one larger-scale outbreak of Shigella sonnei infection occurred in the area of Tao-Yuan, Taiwan. Subsequently, five outbreaks of S. sonnei infection occurred in the same area during the period from October 1998 to February 1999. Fifty-five isolates obtained from these six outbreaks were differentiated by antimicrobial susceptibility testing, plasmid profile analysis (PPA) and pulsed-field gel electrophoresis (PFGE). They were classified into two and three types by antimicrobial susceptibility testing and PPA, respectively. However, only one pattern was observed by PFGE. The molecular epidemiology by PFGE in this study indicated that they were closely-related. These data suggest that the clinical isolates obtained during the period of January 1998 to January 1999 were probably derived from the outbreak strain of 1995.

Inhibition of low density lipoprotein oxidation by tetrahydrofurofuran lignans from Forsythia suspensa and Magnolia coco

Based on the inhibition of Cu(2+)-induced LDL oxidation as marker, the major antioxidants in the fruits of Forsythia suspensa and the stems of Magnolia coco were identified. Of these bioactive tetrahydrofurofuran lignans, pinoresinol, phillygenin, and syringaresinol were more potent than probucol. Sesamin and fargesin, which do not contain phenol groups, were found much less active.

The effect of excess protein on growth performance and protein metabolism of finishing barrows and gilts

Two experiments were conducted to evaluate the effect of excess protein on growth performance, carcass characteristics, organ weights, plasma urea concentration, and liver arginase activity of finishing barrows and gilts. In Exp. 1, 35 barrows and 35 gilts with an initial BW of 51 kg were used. Five pigs of each sex were slaughtered at the start of the study to determine initial body composition. The remaining 60 pigs were allotted to a randomized complete block (RCB) experiment with a 2x5 factorial arrangement of treatments (two sexes x five protein levels: 13, 16, 19, 22, and 25% CP). The experiment continued until the average BW was 115 kg, at which time three blocks of pigs (30 total) were selected randomly and slaughtered. Feed intake decreased with increasing protein concentration (linear, P<.05), and the reduction was greater in gilts than in barrows (P<.05). There was a trend toward a linear negative effect of dietary protein on ADG (P<.10) and also a quadratic effect of protein on protein accretion (P<.10). Fat accretion decreased linearly as protein level increased (P<.05). Increased protein concentrations increased liver, kidney, and pancreas weights (linear, P<.05). Plasma urea concentration increased with each protein concentration, with the exception of the 25 vs. 22% CP treatment in gilts. In Exp. 2, 18 barrows and 18 gilts (BW 63 kg) were allotted to an RCB design consisting of a 2x2 factorial arrangement of treatments with two sexes and two dietary protein concentrations (16 and 25% CP). The experiment was terminated when the average BW of pigs reached 105 kg. Average daily feed intake was greater (P<.10) in barrows than in gilts. Average daily gain was reduced by 18% in gilts when dietary protein was increased from 16 to 25% but was only reduced 3% in barrows (sex x protein, P<.10). Barrows had lighter livers (P<.005), greater arginase activities (P<.05), and greater plasma urea concentrations (P<.005) than did gilts. Increasing dietary protein concentration from 16 to 25% increased liver weight, arginase activity, and plasma urea concentration (P<.005). These data suggest that gilts are more sensitive than barrows to excessive intakes of protein. The more negative effects in gilts may be related to liver metabolic capacity and activity of urea cycle enzymes.

Organization of chromatin in cancer cells: role of signalling pathways

The role of mechanical and chemical signalling pathways in the organization and function of chromatin is the subject of this review. The mechanical signalling pathway consists of the tissue matrix system that links together the three-dimensional skeletal networks, the extracellular matrix, cytoskeleton, and nuclear matrix. Intermediate filament proteins are associated with nuclear DNA, suggesting that intermediate filaments may have a role in the organization of chromatin. In human hormone-dependent breast cancer cells, the interaction between cytokeratins and chromatin is regulated by estrogens. Transcription factors, histone acetyltransferases, and histone deacetylases, which are associated with the nuclear matrix, are components of the mechanical signalling pathway. Recently, we reported that nuclear matrix-bound human and chicken histone deacetylase 1 is associated with nuclear DNA in situ, suggesting that histone deacetylase has a role in the organization of nuclear DNA. Chemical signalling pathways such as the Ras/mitogen-activated protein kinase (Ras/MAPK) pathway stimulate the activity of kinases that modify transcription factors, nonhistone chromosomal proteins, and histones. The levels of phosphorylated histones are increased in mouse fibroblasts transformed with oncogenes, the products of which stimulate the Ras/MAPK pathway. Histone phosphorylation may lead to decondensation of chromatin, resulting in aberrant gene expression.

Effects of surface finish and fatigue testing on the fracture strength of CAD-CAM and pressed-ceramic crowns

STATEMENT OF PROBLEM

All-ceramic molar crowns can be fabricated with CAD-CAM or laboratory methods with different materials, and a polished or oven-glazed surface.

PURPOSE

This in vitro study determined the fracture strength of various all-ceramic crowns, with and without prior cyclic loading.

MATERIAL AND METHODS

Standardized molar crowns were fabricated with a CAD-CAM machine (Cerec 2), software with machinable ceramic materials (Vita Mark II and ProCAD), and also conventional heat-pressed IPS Empress crowns fabricated at 2 dental laboratories. Groups of 40 crowns of each material were manufactured with either a polished or an oven-glazed surface finish. Cyclic loading that simulated oral conditions were performed on half of each group. Afterward, all crowns were loaded until catastrophic failure.Results. Fracture loads of the polished ProCAD crowns without prior cyclic loading was 2120 +/- 231 N, significantly higher than that of the polished Vita Mark II crowns (1905 +/- 235 N), but was not significantly different from the strength of 2 laboratory-fabricated Empress crowns. Oven-glazing of ProCAD crowns improved the fracture strength significantly, up to 2254 +/- 186 N. Prior cyclic loading decreased the strength of all tested crowns significantly, but the reduction was less for the Cerec crowns than the Empress crowns.

CONCLUSION

Cerec ProCAD crowns demonstrated significantly greater strength than the Vita Mark II crowns, better resistance to cyclic loading and lower failure probability than the laboratory-fabricated IPS Empress crowns. Prior cyclic loading significantly reduced the strength of all-ceramic crowns, but had less effect on Cerec crowns than on the IPS Empress crowns. Oven-glazing of ProCAD crowns resulted in significantly higher strength and higher resistance to cyclic loading than surface polishing.

The influence of specific foods and oral hygiene on the microflora of fissures and smooth surfaces of molar teeth: A 5-day study

A group of 20 students, harbouring >10(4) mutans streptococci per millilitre of saliva, was enrolled into the study. Models for sampling, reproducibly, the dental plaque present in specific sites (fissure and smooth surface) on the dentition were developed and validated. Withdrawal of normal oral hygiene procedures for only 1 day resulted in approximately 10-fold increases in the number of micro-organisms recovered from both sites. The effect of supplementing the subjects' diets with particular food items given 5 times per day [lemonade (5.8% w/v sugars, 250 ml), biscuits (digestive biscuits, 67.6% w/w carbohydrate of which 22% w/w was sugars and 45.6% w/w was starch), caramel toffees and sugar lumps] on the number of micro-organisms recovered and on the composition of the flora at both sites was determined. Dental plaque samples were taken after 5 days and it was found that supplementation of the diet with toffee and sugar lumps resulted in significantly more micro-organisms at both sampling sites. The supplementation of the diets with lemonade or biscuits did not significantly alter the numbers of micro-organisms recovered from either site. The percentage composition of the plaque samples from both dental sites remained relatively unaffected by oral hygiene although there were lower levels of mutans streptococci which might be related to the use of an antimicrobial toothpaste containing fluoride, triclosan and zinc citrate. This study suggests that the cariogenicity of certain sucrose-containing foods may, in part, be due to the enhancement of plaque accumulation in addition to other effects on the percentage composition of the plaque which may become manifest on prolonged usage of these dietary foodstuffs. These observations are consistent with dietary survey findings which often find consumption of confectionery related to caries experience or incidence.

Antioxidant principles from Ephemerantha lonchophylla

One dihydrostilbene and three phenanthrene antioxidants were isolated from an ethanolic extract of the Chinese herbal Ephemerantha lonchophylla. One of these compounds, ephemeranthone (4) is a new natural product. Denbinobin (1) and 3-methylgigantol (3) have been previously isolated from this plant, and 3-ethoxy-5-hydroxy-7-methoxy-1,4-phenanthraquinone (2) is an artifact. The structures of these compounds were determined by spectroscopic analysis. The antioxidative activities for inhibiting human low density lipoprotein oxidation in vitro of compounds 1-4 were determined, and only 4 was active (5.3 times that of probucol).

Organization of chromatin in cancer cells: role of signalling pathways

The role of mechanical and chemical signalling pathways in the organization and function of chromatin is the subject of this review. The mechanical signalling pathway consists of the tissue matrix system that links together the three-dimensional skeletal networks, the extracellular matrix, cytoskeleton, and nuclear matrix. Intermediate filament proteins are associated with nuclear DNA, suggesting that intermediate filaments may have a role in the organization of chromatin. In human hormone-dependent breast cancer cells, the interaction between cytokeratins and chromatin is regulated by estrogens. Transcription factors, histone acetyltransferases, and histone deacetylases, which are associated with the nuclear matrix, are components of the mechanical signalling pathway. Recently, we reported that nuclear matrix-bound human and chicken histone deacetylase 1 is associated with nuclear DNA in situ, suggesting that histone deacetylase has a role in the organization of nuclear DNA. Chemical signalling pathways such as the Ras/mitogen-activated protein kinase (Ras/MAPK) pathway stimulate the activity of kinases that modify transcription factors, nonhistone chromosomal proteins, and histones. The levels of phosphorylated histones are increased in mouse fibroblasts transformed with oncogenes, the products of which stimulate the Ras/MAPK pathway. Histone phosphorylation may lead to decondensation of chromatin, resulting in aberrant gene expression.Key words: histone acetylation, histone phosphorylation, nuclear matrix, cytoskeleton, histone deacetylase, cancer.

Acute painful oculomotor nerve paresis caused by pituitary apoplexy--a case report

In a typical case of pituitary apoplexy, a patient, who may or may not be known to harbor a pituitary adenoma, suddenly develops a severe headache. The headache may be retro-orbital, frontal, frontotemporal, or diffuse and may be associated with neck stiffness, neck pain, or both. Ophthalmoplegia may develop within a few hours after the onset of headache. Here we report a rare case of one middle-aged female with pituitary apoplexy initially presenting with acute onset of pupil-involved third cranial nerve palsy, headache and peri-ocular pain. Emergent neuroimaging revealed pituitary apoplexy and immediate intravenous corticosteroid was given and third nerve paresis was improved thereafter. Definite tumor removal was done smoothly after steroid treatment and complete recovery of ophthalmoplegia was noted 2 weeks after operation.

A clinical study of seven cases of trichotillomania in Singapore

The aims of this paper were: to study the profile of trichotillomania cases referred to a child guidance clinic in Singapore, to identify potential risk factors and to study the management and outcome of these cases. This is a descriptive, retrospective study of all cases of trichotillomania presenting to the clinic between January 1996 and January 1998. There were 7 cases seen in a 2-year period which is less than 1% of new cases seen at the clinic. The female to male ratio was 1.33:1 with a mean age of 9.3 years. All cases met the DSM-IV criteria for trichotillomania. All 6 pulled their hair in tufts with 1 who was almost hairless. Associated problems included tics, nail-biting, anxiety and shortness of temper. Treatments included behavioural treatment, stress management, parental education and counselling as well as medications. Two improved and were discharged, with 3 still undergoing treatment and 2 defaulted follow-up. The 7 cases seen in Singapore are similar in clinical features to cases found overseas. A behavioural approach with reduction of environmental stress is most effective. Drugs were less effective. More systematic studies need to be done.

BMP stimulation of bone response adjacent to titanium implants in vivo

The objective of this study was to evaluate the effect of bone morphogenetic protein (BMP) on the bond strength of titanium (Ti) implants at the bone-implant interface. Thirty-six Brånemark screw implants (3.75 mm diameter by 15 mm long) were implanted for 3 and 12 weeks. At 3 weeks after implantation, the mean reverse torque value for implants stimulated with BMP delivered using an atelopeptide type-I collagen carrier (74.2 +/- 5.2 N cm) was observed to be statistically greater (P < 0.000016) than the mean reverse torque value for control Ti implants (32.8 +/- 1.1 N cm). Similarly, at 12 weeks after implantation, the mean reverse torque value for implants stimulated with BMP (89.2 +/- 2.7 N cm) was statistically greater (P < 0.0042) than the mean reverse torque value for control Ti implants (75.8 +/- 2.4 N cm). In addition, histomorphometric evaluations indicated more bone contact with the BMP stimulated implant surfaces compared to the controls after 3 weeks implantation. It was concluded from this study that the use of BMP-atelopeptide type-I collagen mixture is an effective means of obtaining greater bond strength at the bone implant interface within a shorter time period than Ti implants without BMP.