Taxonomic discordance of immersive realities in dentistry: A systematic scoping review.

OBJECTIVES: This review aimed to map taxonomy frameworks, descriptions, and applications of immersive technologies in the dental literature. DATA: The Preferred reporting items for systematic reviews and meta-analyses extension for scoping reviews (PRISMA-ScR) guidelines was followed, and the protocol was registered at open science framework platform (https://doi.org/10.17605/OSF.IO/H6N8M). SOURCES: Systematic search was conducted in MEDLINE (via PubMed), Scopus, and Cochrane Library databases, and complemented by manual search. STUDY SELECTION: A total of 84 articles were included, with 81 % between 2019 and 2023. Most studies were experimental (62 %), including education (25 %), protocol feasibility (20 %), in vitro (11 %), and cadaver (6 %). Other study types included clinical report/technique article (24 %), clinical study (9 %), technical note/tip to reader (4 %), and randomized controlled trial (1 %). Three-quarters of the included studies were published in oral and maxillofacial surgery (38 %), dental education (26 %), and implant (12 %) disciplines. Methods of display included head mounted display device (HMD) (55 %), see through screen (32 %), 2D screen display (11 %), and projector display (2 %). Descriptions of immersive realities were fragmented and inconsistent with lack of clear taxonomy framework for the umbrella and the subset terms including virtual reality (VR), augmented reality (AR), mixed reality (MR), augmented virtuality (AV), extended reality, and X reality. CONCLUSIONS: Immersive reality applications in dentistry are gaining popularity with a notable surge in the number of publications in the last 5 years. Ambiguities are apparent in the descriptions of immersive realities. A taxonomy framework based on method of display (full or partial) and reality class (VR, AR, or MR) is proposed. CLINICAL SIGNIFICANCE: Understanding different reality classes can be perplexing due to their blurred boundaries and conceptual overlapping. Immersive technologies offer novel educational and clinical applications. This domain is fast developing. With the current fragmented and inconsistent terminologies, a comprehensive taxonomy framework is necessary.

Rational Design of New Small Derivatives of 2,2'-Bithiophene as Hole Transport Material for Perovskite Solar Cells.

Using Density Functional Theory (DFT) and Time Dependent DFT (TD-DFT) methods, this inquiry theoretically examines seven novel hole-transport materials (HTMs) namely DFBT1, DFBT2, DFBT3, DFBT4, DFBT5, DFBT6, and DFBT7 based on the 2,2'bithiophene core for future use as HTMs for perovskite solar cells (PSCs). The model molecule has been modified through substituting the end groups situated on the diphenylamine moieties with a tow acceptor bridged by thiophene, this modification was performed to test the impact of the π-bridge and acceptor on the electronic, photophysical, and photovoltaic properties of the newly created molecules. DFBT1 - DFBT7 displayed a lower band gap (1.49 eV to 2.69 eV) than the model molecule (3.63 eV). Additionally, the newly engineered molecules presented a greater λmax ranging from 393.07 nm to 541.02 nm in dimethylformamide solvent, as compared to the model molecule (380.61 nm). The PCEs of all newly designed molecules (22.42% to 29.21%) were high compared with the reference molecule (19.62%). Thus, this study showed that all seven newly small molecules were excellent candidates for a novel PSC.

Association of periodontal therapy, with inflammatory biomarkers and complications in COVID-19 patients: a case control study.

BACKGROUND: In previous studies, COVID-19 complications were reported to be associated with periodontitis. Accordingly, this study was designed to test the hypothesis that a history of periodontal therapy could be associated with lower risk of COVID-19 complications. METHODS: A case-control study was performed using the medical health records of COVID-19 patients in the State of Qatar between March 2020 and February 2021 and dental records between January 2017 and December 2021. Cases were defined as COVID-19 patients who suffered complications (death, ICU admissions and/or mechanical ventilation); controls were COVID-19 patients who recovered without major complications. Associations between a history of periodontal therapy and COVID-19 complications were analysed using logistic regression models adjusted for demographic and medical factors. Blood parameters were compared using Kruskal-Wallis test. RESULTS: In total, 1,325 patients were included. Adjusted odds ratio (AOR) analysis revealed that non-treated periodontitis was associated with significant risk of need for mechanical ventilation (AOR = 3.91, 95% CI 1.21-12.57, p = 0.022) compared to periodontally healthy patients, while treated periodontitis was not (AOR = 1.28, 95% CI 0.25-6.58, p = 0.768). Blood analyses revealed that periodontitis patients with a history of periodontal therapy had significantly lower levels of D-dimer and Ferritin than non-treated periodontitis patients. CONCLUSION: Among COVID-19 patients with periodontal bone loss, only those that have not received periodontal therapy had higher risk of need for assisted ventilation. COVID-19 patients with a history of periodontal therapy were associated with significantly lower D-dimer levels than those without recent records of periodontal therapy. CLINICAL RELEVANCE: The fact that patients with treated periodontitis were less likely to suffer COVID-19 complications than non-treated ones further strengthen the hypothesis linking periodontitis to COVID-19 complications and suggests that managing periodontitis could help reduce the risk for COVID-19 complications, although future research is needed to verify this.

Periodontitis and Intra-Oral Plasmacytosis in a Noonan's Syndrome Patient.

A 13-year-old female patient with Noonan's syndrome, intra-oral periodontitis, and associated periodontal lesions is presented in this case report. The patient suffered early onset severe molar pattern periodontitis and recurrent intra-oral inflammatory lesions, pyogenic granuloma, and plasmacytosis, which were excised and controlled using a strict oral hygiene protocol based on long-term use of chlorhexidine-based products as auxiliary aid to regular home care and brushing.

Efficient Prediction of Missed Clinical Appointment Using Machine Learning.

Public health and its related facilities are crucial for thriving cities and societies. The optimum utilization of health resources saves money and time, but above all, it saves precious lives. It has become even more evident in the present as the pandemic has overstretched the existing medical resources. Specific to patient appointment scheduling, the casual attitude of missing medical appointments (no-show-ups) may cause severe damage to a patient's health. In this paper, with the help of machine learning, we analyze six million plus patient appointment records to predict a patient's behaviors/characteristics by using ten different machine learning algorithms. For this purpose, we first extracted meaningful features from raw data using data cleaning. We applied Synthetic Minority Oversampling Technique (SMOTE), Adaptive Synthetic Sampling Method (Adasyn), and random undersampling (RUS) to balance our data. After balancing, we applied ten different machine learning algorithms, namely, random forest classifier, decision tree, logistic regression, XG Boost, gradient boosting, Adaboost Classifier, Naive Bayes, stochastic gradient descent, multilayer perceptron, and Support Vector Machine. We analyzed these results with the help of six different metrics, i.e., recall, accuracy, precision, F1-score, area under the curve, and mean square error. Our study has achieved 94% recall, 86% accuracy, 83% precision, 87% F1-score, 92% area under the curve, and 0.106 minimum mean square error. Effectiveness of presented data cleaning and feature selection is confirmed by better results in all training algorithms. Notably, recall is greater than 75%, accuracy is greater than 73%, F1-score is more significant than 75%, MSE is lesser than 0.26, and AUC is greater than 74%. The research shows that instead of individual features, combining different features helps make better predictions of a patient's appointment status.

Distal extension of palatal rugae as a limitation for donor soft tissue grafts in a Jordanian population: A cross-sectional study.

BACKGROUND: The purpose of the cross sectional study was to investigate the distal extension of the rugae area in a Jordanian (Middle Eastern) population, as an anatomical limitation influencing the surgical decision of harvesting a palatal soft tissue graft. Factors that may influence or predict the extension were also assessed. METHODS: Sixty periodontally healthy participants (29 males and 31 females) were included. Maxillary alginate impressions were made and casts were poured. The measurements were highlighted from the origin of the rugae (near mid palatine raphe) to the terminal end with a sharp graphite pencil on the cast and a magnification lens was used for identification. The most posterior extension of the rugae were marked on the casts and determined by a standardized periodontal probe. The normal approximation test for binomial distribution was used to determine the proportion of the subjects with rugael extensions beyond the mesial end of the upper second premolar and fisher's exact test for the purpose of analysis of the association of this extension with other factors. RESULTS: In almost half (41.7%) of the sample, the rugae extended distal to the upper second premolar, 23.3% extended to the mid-palatal of the upper second premolar, and 11.7% extended to the mesial of the upper second premolar. The implication is that 90.0% of the rugae reached the upper second premolar and 78.3% extended beyond its mesial aspect. The normal approximation test performed with 95% CI with the "rugael extension proximal to the mesial end of the upper 2nd premolar" considered to be the "success" category revealed that the proportion of the subjects with rugael extensions proximal to the mesial end of the upper second premolar was significantly lower than the proportion beyond the mesial end of the upper second premolar (95% CI of 11.2-32.0%, p = .00001). There was no significant difference between gender, smoking status, gingival phenotype and palatal shape with the posterior extension of palatal rugae. CONCLUSIONS: Palatal rugae in a sample of a Jordanian population extends beyond the mesial aspect of the upper second premolar which may cause a substantial limitation for graft harvesting from the palate. The hard palate of Jordanian patients may not be a reliable source of soft tissue grafts required for aesthetic mucogingival surgery. No significant association existed between the most posterior extent of palatal rugae and gender, gingival phenotype or palatal shape. Other possible sources should be explored.

Association between periodontitis and severity of COVID-19 infection: A case-control study.

AIM: COVID-19 is associated with an exacerbated inflammatory response that can result in fatal outcomes. Systemic inflammation is also a main characteristic of periodontitis. Therefore, we investigated the association of periodontitis with COVID-19 complications. MATERIALS AND METHODS: A case-control study was performed using the national electronic health records of the State of Qatar between February and July 2020. Cases were defined as patients who suffered COVID-19 complications (death, ICU admissions or assisted ventilation), and controls were COVID-19 patients discharged without major complications. Periodontal conditions were assessed using dental radiographs from the same database. Associations between periodontitis and COVID 19 complications were analysed using logistic regression models adjusted for demographic, medical and behaviour factors. RESULTS: In total, 568 patients were included. After adjusting for potential confounders, periodontitis was associated with COVID-19 complication including death (OR = 8.81, 95% CI 1.00-77.7), ICU admission (OR = 3.54, 95% CI 1.39-9.05) and need for assisted ventilation (OR = 4.57, 95% CI 1.19-17.4). Similarly, blood levels of white blood cells, D-dimer and C Reactive Protein were significantly higher in COVID-19 patients with periodontitis. CONCLUSION: Periodontitis was associated with higher risk of ICU admission, need for assisted ventilation and death of COVID-19 patients, and with increased blood levels of biomarkers linked to worse disease outcomes.

Anatomic factors influencing dimensions of soft tissue graft from the hard palate. A clinical study.

OBJECTIVES: The aim of the present study was to measure the thickness of the palatal mucosa in a Jordanian (Middle Eastern) population as well as identify possible factors that may influence the thickness of palatal mucosa. MATERIAL AND METHODS: Sixty period on tally healthy subjects (29 males and 31 females) were selected. Fifteen measurement points were defined on the palate. The mucosal thickness in the hard palate was determined by "bone sounding" with a Hu-Friedy® round periodontal probe. RESULTS: The overall mean thickness of the palatal masticatory mucosa was 3.23 ± 0.47 mm.The mean thickness increased from the gingival margin to a more apical position irrespective of the tooth measured or side of the mouth in the following sequence: canine, second molar, first premolar, second premolar and lastly, the first molar. No significant difference between gender, smoking status, gingival phenotype andsides of the mouth with the thickness of palatal masticatory mucosa was determined. A significant difference between palatal shape and palatal gingival thickness was found. CONCLUSIONS: The most appropriate site for graft harvesting is the canine-premolar area 8-13 mm from the mid-palatal aspect of each respective tooth in a Jordanian population. Except for the palatal shape, the side of the mouth, smoking, gender or gingival phenotype does not affect the graft harvest. CLINICAL RELEVANCE: SCIENTIFIC RATIONALE FOR STUDY: Knowledge on the thickness of the masticatory mucosa is crucialin making decisions for surgical treatment modality and may affect surgical outcome. We measured the thickness of the palatal mucosa in a Jordanian population and identified possible influencing factors. PRINCIPAL FINDINGS: The thickness varied according to the teeth and the canine to premolar region was found to be the appropriate donor site. PRACTICAL IMPLICATIONS: This information on safe zone for graft harvest can guide the periodontist to make appropriate incisions and choose the appropriate location to obtain a graft of adequate thickness and dimensions.

ENDOSCOPIC FINDINGS OF UPPER GASTROINTESTINAL BLEEDING IN PATIENTS WITH LIVER CIRROSIS.

BACKGROUND: Acute upper gastrointestinal (GI) bleeding is a common medical emergency. A common risk factor of upper GI bleeding is cirrhosis of liver, which can lead to variceal haemorrhage. 30-40% of cirrhotic patients who bleed may have non-variceal upper GI bleeding and it is frequently caused by peptic ulcers, portal gastropathy, Mallory-Weiss tear, and gastroduodenal erosions. The objective of this study was to determine the frequency of upper gastrointestinal endoscopic findings among patients presenting with upper gastrointestinal bleeding with liver cirrhosis. METHODS: This descriptive cross-sectional study was carried out in Gastroenterology & Hepatology Department of Ayub Teaching Hospital, Abbottabad from February 2012 to June 2013. 252 patients diagnosed with cirrhosis, presenting with upper GI bleed, age 50 years of either gender, and were included in the study. Non-probability consecutive sampling was used, Endoscopy was performed on each patient and the findings documented. RESULTS: The mean age was 57.84 +/- 6.29 years. There were 158 (62.7%) males and 94 (37.3%) females. The most common endoscopic finding was oesophageal varices (92.9%, n=234) followed by portal hypertensive gastropathy (38.9%, n=98) with almost equal distribution among males and females. Gastric varices were found in 33.3% of patients (n=84). Among other non-variceal lesions, peptic ulcer disease was seen in 26 patients (10.3%) while gastric erosions were found in 8 patients (3.2%). CONCLUSION: In patients with acute upper GI bleeding and liver cirrhosis, the most common endoscopic finding is oesophageal varices, with a substantially higher value in our part of the country, apart from other non-variceal causes.

FREQUENCY AND SEVERITY OF STEATOSIS IN PATIENTS WITH CHRONIC HEPATITIS-C.

BACKGROUND: Hepatitis-C viral infection is a global health problem. It has been estimated that approximately 170 million individuals are infected with hepatitis-C virus. Hepatic steatosis is a frequent histological feature in patients with chronic hepatitis-C infection. Histological examinations show that up to 50% of these patients have variable degrees of hepatic steatosis, even in the absence of other possible steatogenic factors like alcohol, drugs or metabolic syndromes. The objective of this study was to determine the frequency and severity of steatosis in patients with Chronic Hepatitis-C. METHODS: This cross sectional study was carried out from 1st January 2010 to 1st July 2010 at the department of Gastroenterology PIMS, Islamabad. A total of 127 patients of chronic hepatitis-C were enrolled in the study after taking informed written consent. Frequency and severity (mild, moderate and severe) of steatosis was assessed on the basis of liver biopsy. RESULTS: A total of 127 patients were included in the study. Mean age of the patients was 36.24 years. Out of 127 patients, 48 (38%) were male and 79 (62%) were female. Steatosis was present in 50(39%) patients with chronic hepatitis-C infection. whereas steatosis was absent in 77 (61%) patients. CONCLUSION: The presence of steatosis on liver biopsy in patients with chronic hepatitis-C is common (39% patients) and female patients had slightly more severe degree of steatosis as compared to male patients.

Comparison of primary wound closure with delayed primary closure in perforated appendicitis.

BACKGROUND: Delayed primary closure in cases of acute appendicitis is debated among the surgeons as to whether it decreases the rate of wound infection in comparison to primary closure. The aim of this study was to find out the optimal method of wound closure in cases of perforated appendicitis. METHODS: This randomized control trial was conducted at the surgical units of Ayub Teaching Hospital Abbottabad from May to November 2012. A total of 158 patients having perforated appendicitis were included in the study. They were randomly divided two groups. The wounds were primarily closed in one group and left open with daily saline soaked dressing, to be closed on postoperative day 4 in case of the other group. The main outcome measure was wound infection. A wound was considered infected if it was discharging pus, was red and swollen on postoperative day 8th. The method of wound closure was considered efficacious if there was no wound infection till 8th postoperative day. RESULTS: A total of 158 patients, 56 (35.4%) male and 102 (64.6%) female were included in the study. Primary closure group had a total number of 79 patients with 26 (32.9%) male and 53 (67.1%) female. Delayed primary group had also a total number of 79 patients with 30 (38%) male and 49 (62%) female. The mean age of patients in the primary closure group was 26.67 ± 7.32 years while in the delayed primary group was 28.15 ± 6.88 years. In the entire series, 36 (22.8%) patients developed wound infection. There was a significant association between wound infection and type of skin closure (Delayed Primary Closure 6.3% vs. Primary Closure 39.2%, p < 0.000). CONCLUSION: Delayed Primary closure is the optimal management strategy in case of perforated appendicitis as it decreases the incidence of wound infection.

Endoscopic findings in patients presenting with oesophageal dysphagia.

BACKGROUND: Dysphagia is the difficulty in swallowing and is often described by the patients as a 'perception' that there is an impediment to the normal passage of the swallowed material. It is frequently observed that there is an association of dysphagia with serious underlying disorders and warrants early evaluation. The current study aimed to determine the frequency of common endoscopic findings in patients presenting with oesophageal dysphagia. METHODS: This cross-sectional descriptive study was carried out in the department of Gastroenterology, Ayub Medical College, Abbottabad, from October 2012 to April 2013. Consecutive patients with dysphagia were included in the study and were subjected to endoscopy. RESULTS: A total of 139 patients presenting with dysphagia were studied, 81 (58.3%) were males and 58 (41.7%) were females. The mean age was 52.41 ± 16.42. Malignant oesophageal stricture was the most common finding noted in 38 (27.3%) patients with 28 (73.7%) males and 23 (60.5%) patients among them were above the age of 50 years. It was followed by normal upper Gastrointestinal (GI) endoscopy in 29 (20.9%) patients and reflux esophagitis in 25 (18.0%) patients. Schatzki's ring was present in 14 (10.1%) patients; benign oesophageal strictures in 12 (8.6%) patients while achalasia was noted in 7 (5.0%) patients. 14(10.1%) patients had findings other than the ones mentioned above. CONCLUSION: Malignancies are a more common cause of dysphagia in our population and early diagnosis can result in proper treatment of many of these cases.

Management of ectopic varix with histoacryl.

Upper gastro-intestinal (GI) bleed is one of the most serious situations encountered in the emergency department. There is consensus regarding management of common causes of upper GI bleed but for rare causes no such consensus exists. We present a case of a 35 year old male who presented with 5-6 episodes of hematemesis associated with melena in 24 hours. On examination he was in hypotensive shock with no stigmata of chronic liver disease. Doppler studies showed portal vein thrombosis with cavernous transformation and varices in peripancreatic region and around duodenum. His upper GI endoscopy showed a large varix with ulceration in the duodenal bulb, indicating it as the source of bleeding. The varix was injected with 1cc of cyanoacrylate. The patient's final diagnosis was non-cirrhotic portal hypertension secondary to portal vein thrombosis. At immediate and long termfollow-up the patient had no complications. We conclude that cyanoacrylate injection effectively manages ectopic duodenal varices and can be used with a simple application technique.

Use of the Q-switched Nd:YAG laser for the treatment of pigmentary disorders in Egyptians.

BACKGROUND AND OBJECTIVE: Laser treatment of cutaneous pigmentation is one of the most interesting areas in cutaneous surgery. Our purpose was to study the efficacy of Q-switched Nd:YAG at 1064 nm and 532 nm for the treatment of some pigmented lesions in our locality in Egypt. METHODS: A total of 60 subjects were treated with the Q-switched Nd:YAG laser with fluences ranging from 8 to 10 J/cm(2) for dermal lesions and 2.5-5 J/cm(2) for epidermal lesions. The number of sessions ranged from one to six sittings for epidermal lesions, four to six sessions for dermal lesions, while the mixed group required two to three sessions. RESULTS: A total of 34 patients (56.7%) showed excellent response, seven patients (11.7%) showed good response, nine patients (15%) showed fair response, and 10 (16.6%) showed poor response. Transient postinflammatory hyperpigmentation occurred in five patients (8.33%) and erythema in seven patients (11.66%). Complications were common in darker skin types V and VI. CONCLUSION: The Q-switched Nd:YAG laser is an effective and safe technique for the treatment of pigmented skin lesions. Adverse hyperpigmentation can occur but is transient.

A clinical study on the effects of cordless and conventional retraction techniques on the gingival and periodontal health.

AIM: To investigate the influence of two cordless techniques on the periodontium in comparison with conventional cords. MATERIAL AND METHODS: Dental students (n=60) with healthy gingival conditions were recruited - an expanding poly vinyl siloxane material (Magic Foam Cord), a paste-like material (Expasyl), and a conventional retraction cord (Ultrapak) were applied on the buccal aspects of three premolars of each subject. Probing depth, clinical attachment level, gingival index (GI), plaque index, mobility, bleeding, and sensitivity were assessed at baseline, and at 1 and 7 days after application. Data were analysed using Kruskal-Wallis and Mann-Whittney tests (alpha=0.05). RESULTS: The periodontal parameters were not statistically significant among the groups at all time intervals except for the GI, which was increased for all groups after 1 day. The highest was in Expasyl (p=0.011). After 7 days, the GI returned to a non-significant level compared with baseline except for Expasyl, which was still significant (p=0.044). Expasyl induced sensitivity in four subjects. Bleeding was only induced by Ultrapak in 28.3% and 26.7% during and after retraction, respectively. CONCLUSIONS: All techniques caused a temporary gingival inflammation; the greatest was in Expasyl, which also showed slower recovery. Cordless techniques did not induce bleeding during or after retraction.

Dental health attitudes and behaviour among dental students in Jordan.

OBJECTIVE: Examine and compare differences in oral health attitudes and behaviour among Jordanian dental students. BASIC RESEARCH DESIGN AND PARTICIPANTS: Cross-sectional study of 314 dental students was conducted to compare differences in oral health behaviour and attitudes among these students in different levels of academic education. SETTING: Jordan University of Science and Technology. METHODS: Subjects were surveyed using a modified version of the Hiroshima University Dental Behavior Inventory (HU-DBI) questionnaire (20 Items). Multivariate binary and polytomous logistic regression analyses were performed in order to study change of patterns of statements during preclinical and clinical, and year of study, respectively. RESULTS: The percentage of students claiming to brush their teeth twice daily or more often was four times higher amongst clinical students than amongst pre-clinical students.. The odds of visiting a dentist only in case of toothache was reduced by a factor of more than three among clinical year students (OR 0.30, 95% CI 0.15-0.61). Clinical year students rarely complained of bleeding gums after toothbrushing (OR 0.10, 95% CI 0.03-0.27). On the other hand, a number of items regarding use of dental floss and tooth paste, bad breath, colour and appearance of teeth, and cigarette smoking was similar between preclinical and clinical students. Evaluation of trends during dental studies employing polytomous multivariate logistic regression analysis revealed an abrupt change at the end of preclinical studies for items characterizing professional attitude. CONCLUSIONS: With advancement in dental school, dental student's oral health awareness and attitudes improved in some aspects. Preventive dentistry courses should be taught early in the dental curriculum of the pre-clinical years.

Smoking prevalence and its effect on dental health attitudes and behavior among dental students.

OBJECTIVE: To determine smoking prevalence and its effect on dental health attitudes and behavior among dental students in Jordan. SUBJECTS AND METHODS: A cross-sectional study of 314 dental students was conducted at Jordan University of Science and Technology. Subjects were surveyed using a modified version of the Hiroshima University Dental Behavior Inventory (HU-DBI) questionnaire. Multivariate logistic regression analyses were performed to study differences between male smokers and nonsmokers only. RESULTS: The response rate was 83.7%, with 48% males and 52% females. The prevalence of smoking was 17.2%. Smoking was more prevalent among male students (31%) than female (4.3%). For male students, the multivariate logistic regression analysis showed 6 items that were different between smokers and nonsmokers. Nonsmokers tended to brush their teeth more often than smokers (OR 8.67, 95% CI 1.66-45.25); claimed that they had never been professionally taught how to brush their teeth (OR 11.15, 95% CI 1.89-65.67); believed that they spend too much time brushing their teeth (OR 12.24, 95% CI 2.0-75.05); were more concerned about having bad breath (OR 41.86, 95% CI 3.44-58.75) and were more concerned about the color of their gums (OR 8.04, 95% CI 1.55-41.84). CONCLUSIONS: Smoking prevalence among male dental students in Jordan was high, 7 times greater than for females. Male smokers and nonsmokers had different attitudes and oral health behaviors as indicated by the study survey.

Effects of short-term administration of valproate on serotonin-1A and dopamine receptor function in healthy human subjects.

OBJECTIVE: To examine the effects of short-term valproate treatment on human brain serotonin and dopamine function by means of challenge tests with ipsapirone, a partial agonist at 5-HT1A receptors, and apomorphine, a dopamine receptor agonist. DESIGN: Experimental challenge-rechallenge, within-subjects repeated measures, before and at the end of 14 days of treatment with valproate at a dosage of 625 mg/d (reached gradually over the first 5 days). PARTICIPANTS: Eight healthy male volunteers (mean age 38 years) selected for good physical and mental health who were nonsmokers. OUTCOME MEASURES: Pharmacological probes were used to evaluate the effects of valproate. In the ipsapirone challenge, changes in adrenocorticotropic hormone (ACTH), cortisol and body temperature were measured, and in the apomorphine challenge, growth hormone (GH) and prolactin were the dependent variables. RESULTS: Valproate treatment did not significantly alter the ACTH, cortisol or body temperature responses to ipsapirone (20 mg by mouth), which reached equivalent plasma levels at each challenge. Similarly, valproate treatment did not alter the GH or prolactin responses to apomorphine (5 micrograms/kg subcutaneously). CONCLUSIONS: These results suggest that short-term treatment with valproate at a dose of 625 mg/d does not alter hypothalamic or pituitary 5-HT1A or dopamine receptor responses to challenges with ipsapirone and apomorphine, respectively.

DNA single strand breaks induced by low levels of occupational exposure to styrene: the gap between standards and reality.

Styrene is a known mutagen and suspected carcinogen, used in the reinforced plastic industry. This study aims to identify the occurrence of DNA single strand breaks (SSBs) in workers exposed to styrene levels far below the recommended standards. We compared 26 exposed workers with 26 control subjects and found a significant increase in the incidence of DNA-SSBs in the exposed individuals. The levels of the biological indices of exposure (urinary mandelic and phenyl glyoxylic acids) were less than 25% of the recommended limits. Reduction of the threshold limit values/time-weighted-average (TLV-TWA) applied is strongly recommended.