Superimposition of sequential scans to measure erosion on unpolished and curved human enamel

OBJECTIVES

To determine if superimposition of sequential scans can discriminate between different fluorides at step heights less than 5 μm on natural human enamel surfaces.

MATERIALS AND METHODS

Natural, unpolished, human enamel specimens (n = 60) were randomly assigned to one of three pre-treatment toothpaste slurries with a calcium silicate/fluoride, fluoride-only and a control. Baseline and post treatment scans, from a non-contacting profilometer with a 0.01 μm z-axis and <1 μm lateral scanning resolution were imported into superimposition software to define change in mean 3D step height and surface roughness following erosion in 0.3 % citric acid for 15 min. Statistical analysis conducted with two-way repeated measures ANOVA and post-hoc Tukey's multiple comparisons.

RESULTS

Confidence and resolution of superimposition and subtraction of repeated profiles from unpolished enamel revealed accuracy within 1-2 μm. The technique was able to discriminate between the fluorides demonstrating statistical differences in mean (SD) 3D step height (μm) of 1.96 (0.40) and 2.75 (0.49) (p=0.0024). There was a statistically significant increase in surface roughness for all groups after 15 min erosion compared to baseline. But no statistically significant difference between the interventions after 15 min erosion but there was compared to no fluoride (p=0.006).

CONCLUSION

Superimposition and subtraction of profiles could discriminate between fluoride interventions, which showed statistical differences in enamel loss differences less than 3 μm.

CLINICAL SIGNIFICANCE

This erosion model and data analysis workflow was able to distinguish differences between scans of 3 μm on unpolished enamel following the interaction with fluoride.

Evaluating denture cleanliness of patients in a regional dental hospital

Aims To evaluate the quality of clinical record keeping and determine quality of denture cleanliness; record baseline denture cleanliness for 60 patients; introduce denture hygiene instruction (DHI); and then re-assess the patients for improvement and enhanced record keeping.Methods Analysis of patients' denture hygiene instruction record keeping (n = 60) was undertaken retrospectively. The Denture Cleanliness Index (DCI) was utilised to assess denture cleanliness (best score 0, worst score 4). Baseline DCI scores were taken and individual DHI was delivered. After one month, patients were reviewed and scored, with record keeping quality analysed.Results At baseline, 11.7% (n = 7) of patients had DCI scores of ≤2, improving to 93.8% (n = 45) after one month, demonstrating short-term improvement in denture cleanliness. Only 63% (n = 38) of patients had evidence of a record of DHI within their notes at baseline, improving to 100% at recall.Conclusions New patient information leaflet and clinical guidelines on denture hygiene have been written and implemented. The results of this study suggest that this may be a relatively straightforward method to achieve a short-term improvement in denture cleanliness. The implementation of a DCI score is helpful in allowing patients to improve denture hygiene and its wider use is supported.

Growth velocity and final height in elite female rhythmic and artistic gymnasts

PURPOSE

The aim of this study was to determine the impact of intensive training on adult final height in elite female rhythmic and artistic gymnasts.

METHODS

The study included 215 rhythmic gymnasts (RG) and 113 artistic gymnasts (AG).

RESULTS

AG were below the 50th percentile, while RG were taller than average. Final adult height was lower than target height in AG, while in RG, it exceeded target height. AG started training earlier than RG (p<0.001) and reported lower intensity of training (p<0.001). RG were taller than AG, with higher target height, greater Δ final height-target height and lower body fat and BMI (p<0.001). Using multiple regression analysis, the main factors influencing final height were weight SDS (p<0.001), target height SDS (p<0.001) and age of menarche (p<0.001) for RG, and weight SDS (p<0.001) and target height SDS (p<0.001) for AG.

CONCLUSION

In both elite female RG and AG, genetic predisposition to final height was not disrupted and remained the main force of growth. Although in elite RG genetic predisposition for growth was fully preserved, in elite female AG final adult height falls shorter than genetically determined target height, though within the standard error of prediction.

Abolished circadian rhythm of salivary cortisol in elite artistic gymnasts

OBJECTIVE

The aim of this study was to evaluate the effects of intensive physical exercise and acute psychological stress during high level athletic competition as reflected on the levels of salivary cortisol in elite artistic gymnasts (AGs).

DESIGN

The study included 239 AGs (142 females-97 males) who participated in the European Championship of Gymnastics in 2006 and 81 adolescents (40 females-41 males), matched for age, as controls. All athletes participated voluntarily in all or parts of the study, providing samples or data for each of the variables measured. Height, weight, body fat, lean body mass (LBM), bone age and Tanner stage of puberty were assessed and data concerning the time of thelarche, adrenarche and menarche as well as, the onset and the intensity (hours per week) of training were obtained.

METHODS

Saliva samples were collected, the morning before training and in the afternoon shortly after the competition. From controls, the saliva samples were collected in the morning. Cortisol concentrations were measured using a chemiluminescence method. Acute stress was assessed using a questionnaire designed for the study.

RESULTS

No difference was found between morning and afternoon salivary cortisol levels in both male and female AGs (females: AM: 15.45±7.45nmol/l vs PM: 15.73±9.38nmol/l; males: AM: 10.21±5.52nmol/l vs PM: 9.93±13.8nmol/l, p>0.05). Female AGs presented higher levels of morning salivary cortisol than female controls (p<0.05). Both male and female AGs had higher degree of psychological stress in comparison with controls (p<0.001, p<0.013, respectively). Female AGs had higher morning and afternoon salivary cortisol levels (p<0.01, p<0.01, respectively) and higher degree of stress (p<0.003) than males.

CONCLUSIONS

In elite AGs the diurnal rhythm of salivary cortisol has been abolished, probably due to the strenuous training and competition conditions. Female AGs presented higher levels of morning salivary cortisol and psychological stress compared to both male AGs and female controls. The long term consequences of these modifications of the HPA axis remain to be elucidated.

Dissociation of thyrotropin and leptin secretion in acute surgical stress in severely obese patients

BACKGROUND

During illness, thyroid parameters undergo acute changes, which are known as non-thyroidal illness syndrome, the cause of which has not been elucidated. In vitro and in vivo data demonstrate that leptin regulates the expression of thyrotropin-releasing hormone (TRH)-mRNA in the paraventricular nucleus as well as the secretion of thyrotropin (TSH) in response to fasting in humans and animals. Moreover, in healthy adults, TSH and leptin have almost identical circadian rhythms. Our aim was to investigate the secretion of leptin and TSH, and their probable interaction, during the acute stress that is induced by surgery.

METHODS

We studied 18 severely obese but otherwise healthy men. All participants were admitted to the hospital in the morning after an overnight fast. On the following day, 14 of the participants underwent bariatric surgery at 0900. The remaining four participants did not undergo surgery and served as controls. Serum samples to measure the levels of TSH and leptin were collected from all participants, as follows: upon admission to the hospital (baseline values) and on the following day at 0900 and every 10 min, thereafter for 9 h.

RESULTS

The serum TSH increased during the first hour after skin incision (si) and then decreased gradually throughout the rest of the observation period. In contrast, during the first hour after si, the leptin levels remained unaltered. The leptin levels then decreased and reached a nadir at 4 h and 10 min post si after which they remained constant for approximately 1 h. Thereafter, while TSH continued to decrease, leptin started to increase and reached baseline values at 9 h post si. In control subjects, the TSH and leptin profiles seemed parallel each other.

CONCLUSIONS

During acute surgical stress, the secretion of TSH and leptin in severely obese men is asynchronous and causality could not be proven.

Treating iodine deficiency: long-term effects of iodine repletion on growth and pubertal development in school-age children

BACKGROUND

Iodine deficiency (ID) is still a major universal health problem. Iodine deficiency disorders (IDDs) affect people of all ages, among whom the most vulnerable are children and adolescents. The aim of the present study was to assess the long-term effects on growth and pubertal development of correcting severe ID in areas of Azerbaijan between 1999 and 2000.

METHODS

Iodized oil was administered orally to 293,000 children, aged 6-16 years. Among those, 364 children were randomly selected and were examined 1 year before the administration of iodized oil (Group I-neg, iodine negative) and 295 children (Group I-Rx, iodine treated) were examined 4 years (Group I-R x 4, iodine treated 4 years later; n = 173) or 5 years (Group I-R x 5, iodine treated 5 years later; n = 122) after the last dose of iodide.

RESULTS

In Group I-neg the median urine iodine concentration (UIC) (mcg/L) was 36 (mean: 36.272 +/- 11.036) and increased significantly (p < 0.001) in Group I-R x 4: 188 (mean: 230.969 +/- 155.818) and in Group I-R x 5: 175 (mean: 201.176 +/- 130.369). The prevalence of goiter was 99% in Group I-neg and 2% in Group I-R x 4. Children in Group I-Rx had a greater standard deviation score (SDS) for height (-0.1364 +/- 1.279, n = 294) than children in Group I-neg (-0.5019 +/- 1.17, n = 363) (p < 0.001, t = -3.817), which was more significant for boys. SDS for weight was similar in both groups (Group I-neg: -0.17 +/- 0.78, n = 363; Group I-Rx: -0.115 +/- 0.917, n = 294). The rate of puberty development as judged by the development of breast and pubic hair was normalized in both sexes after the correction of ID.

CONCLUSIONS

Our results demonstrate that long-term correction of severe ID leads to sustained improvement of linear growth accompanied by a normalization of the time of onset of pubertal development for both sexes.

Abdominal radiation initiates apoptotic mechanism in rat femur bone marrow cells in vivo that is reversed by IGF-1 administration

PURPOSE

Radiation induces apoptosis as a result of damage to cellular DNA and RNA. The aim of our work was to study the effect of radiation on rat bone marrow cells (as a neighboring tissue) in the context of a model of experimental radiation enteritis in rats. The effect of systematic administration in irradiated animals of r-IGF-1 and GH was also studied.

MATERIALS AND METHODS

Wistar type, normal rats, were divided in 4 groups. One control group and the other 3 groups were irradiated in the abdomen. The measured scattered irradiation in the femur ranged from 16.5 to 47.3 cGy. In 2 groups of irradiated animals, rIGF-1 (0.1 microg/g of body weight twice/d) and rGH (0.25 microg/g of body weight /d) were administered. Bone marrow cells were harvested from both femurs. DNA and RNA were analyzed in specific gels. The m-RNA was hybridized for c-fos proto-oncogene expression.

RESULTS

The calculated low dose of radiation that affected the femurs of the animals induced reduction in bone marrow cell numbers and endonuclease activation manifested by subsequent fragmentation of DNA and RNA. This phenomenon was reversed by rGH and rIGF-1 administration. The c-fos proto-oncogene expression was upregulated by irradiation.

CONCLUSION

These observations indicate that scattered low dose radiation is capable of initiating apoptosis in rat bone marrow cells and rGH and rIGF-1 administration reverse this process.

Growth, pubertal development, skeletal maturation and bone mass acquisition in athletes

The genetic potentials for growth can be fully expressed only under favourable environmental conditions. Excessive physical training may negatively affect growth, especially during puberty. Sports that require a strict control of energy input in the presence of a high energy output are of particular concern. In gymnastics, a different pattern in skeletal maturation was observed, leading to an attenuation of growth potential ins Artistic Gymnasts (AG), more pronounced in males than in females, whereas in female Rhythmic Gymnasts (RG) the genetic predisposition to growth was preserved because of a late catch-up growth phenomenon. In all other sports not requiring strict dietary restrictions, no deterioration of growth has been documented. Intensive physical training and negative energy balance modify the hypothalamic pituitary set point at puberty, prolong the prepubertal stage and delay pubertal development and menarche in a variety of sports. In elite RG and AG the prepubertal stage is prolonged and pubertal development is entirely shifted to a later age, paralleling the bone age rather than the chronological age. Bone formation, and, consequently, BMD are enhanced by physical activity. In athletes, high-impact loading activities have been shown to improve BMD, while in sports requiring a lean somatotype, the delay in skeletal maturation and pubertal development, resulting from hypoestrogenemia, predisposes athletes to osteopenia. In AG, an increase in bone density is observed using the bone age as denominator.

The influence of intensive physical exercise on bone acquisition in adolescent elite female and male artistic gymnasts

Physical exercise enhances bone acquisition during adolescence. The aim of the study was to evaluate the influence of intensive physical exercise on bone acquisition in adolescent elite artistic gymnasts. The study included 262 athletes (93 males and 169 females, aged 13-23 yr) participating in the 24th European Championship held in Greece. Bone age compared with chronological age was delayed by 2 yr for females (n = 120) and 1 yr for males (n = 68). For both sexes, the growth chart of bone mineral density (BMD) followed a normal pattern when estimated according to bone age rather than chronological age. For females, BMD was positively correlated with bone age, chronological age, height, body weight, body mass index, body fat, lean body mass, and with age of onset of training, and negatively with duration of exercise and intensity of training (P values range from <0.05 to <0.0001). Multiple regression analysis revealed that age of onset of training was the major parameter attenuating the effect of exercise on BMD (P < 0.001). The latter was related to the stage of puberty (P < 0.05). For males, BMD was correlated positively with bone age, height, body weight, and lean body mass (P values range from <0.01 to 0.0001). Multiple regression analysis revealed that the more powerful factor influencing BMD was weight (P < 0.01). In conclusion, bone acquisition in adolescents under intensive physical training follows the normal pattern only when estimated according to bone age. The age of onset, the duration, and the intensity of exercise attenuate the bone acquisition, at least in female artistic gymnasts.

Effects of growth hormone and insulin-like growth factor-I on radiation enteritis. a comparative study

The effect of growth hormone (GH) and insulin-like growth factor-I (IGF-I) on intestinal mucosal integrity and bacterial translocation after abdominal radiation was studied in rats. Animals were divided into the following groups: I (control), II (radiation), III (radiation plus GH) and IV (radiation plus IGF-I). Radiation (1,100 cGy) was administered on the 1st day to groups II, III and IV. GH [0.25 mg/kg body weight (BW) s.c. once daily] was administered on days 1, 2 and 3 to group III, and IGF-I (0.1 mg/kg BW s.c. twice daily) was given on days 1, 2 and 3 to group IV. On day 4, animals were sacrificed. Cultures of the mesenteric lymph nodes (MLN) and blood cultures from aorta and portal vein were performed. The number of villi per centimeter (V/cm), the villus height (Vh), mitoses per crypt (M/C) and protein and DNA contents of the mucosa were evaluated in samples from the terminal ileum. Radiation increased the number of positive MLN cultures, while treatment with GH and IGF-I reduced them significantly. V/cm, Vh, M/C, protein and DNA contents were significantly increased in all irradiated animals treated with GH and IGF-I. In conclusion both GH and IGF-I are not only capable of improving the mucosal integrity but also to reduce the bacterial translocation that follows intestinal radiation. In small doses IGF-I could reproduce the effects of GH and in some parameters the effects were more pronounced, although not statistically significant. This suggests that the effects of GH on intestine could be mediated through the local and systemic generation of IGF-I.