Anticoagulation Versus Antiplatelets in Spontaneous Cervical Artery Dissection: A Systematic Review and Meta-Analysis.

BACKGROUND: It is uncertain whether antiplatelets or anticoagulants are more effective in preventing early recurrent stroke in patients with cervical artery dissection. Following the publication of the observational Antithrombotic for STOP-CAD (Stroke Prevention in Cervical Artery Dissection) study, which has more than doubled available data, we performed an updated systematic review and meta-analysis comparing antiplatelets versus anticoagulation in cervical artery dissection. METHODS: The systematic review was registered in PROSPERO (CRD42023468063). We searched 5 databases using a combination of keywords that encompass different antiplatelets and anticoagulants, as well as cervical artery dissection. We included relevant randomized trials and included observational studies of dissection unrelated to major trauma. Where studies were sufficiently similar, we performed meta-analyses for efficacy (ischemic stroke) and safety (major hemorrhage, symptomatic intracranial hemorrhage, and death) outcomes using relative risks. RESULTS: We identified 11 studies (2 randomized trials and 9 observational studies) that met the inclusion criteria. These included 5039 patients (30% [1512] treated with anticoagulation and 70% [3527]) treated with antiplatelets]. In meta-analysis, anticoagulation was associated with a lower ischemic stroke risk (relative risk, 0.63 [95% CI, 0.43 to 0.94]; P=0.02; I2=0%) but higher major bleeding risk (relative risk, 2.25 [95% CI, 1.07 to 4.72]; P=0.03, I2=0%). The risks of death and symptomatic intracranial hemorrhage were similar between the 2 treatments. Effect sizes were larger in randomized trials. There are insufficient data on the efficacy and safety of dual antiplatelet therapy or direct oral anticoagulants. CONCLUSIONS: In this study of patients with cervical artery dissection, anticoagulation was superior to antiplatelet therapy in reducing ischemic stroke but carried a higher major bleeding risk. This argues for an individualized therapeutic approach incorporating the net clinical benefit of ischemic stroke reduction and bleeding risks. Large randomized clinical trials are required to clarify optimal antithrombotic strategies for management of cervical artery dissection.

Transcarotid Arterial Revascularization of Symptomatic Internal Carotid Artery Disease: A Systematic Review and Study-Level Meta-Analysis.

BACKGROUND: Transcarotid artery revascularization (TCAR) is an interventional therapy for symptomatic internal carotid artery disease. Currently, the utilization of TCAR is contentious due to limited evidence. In this study, we evaluate the safety and efficacy of TCAR in patients with symptomatic internal carotid artery disease compared with carotid endarterectomy (CEA) and carotid artery stenting (CAS). METHODS: A systematic review was conducted, spanning from January 2000 to February 2023, encompassing studies that used TCAR for the treatment of symptomatic internal carotid artery disease. The primary outcomes included a 30-day stroke or transient ischemic attack, myocardial infarction, and mortality. Secondary outcomes comprised cranial nerve injury and major bleeding. Pooled odds ratios (ORs) for each outcome were calculated to compare TCAR with CEA and CAS. Furthermore, subgroup analyses were performed based on age and degree of stenosis. In addition, a sensitivity analysis was conducted by excluding the vascular quality initiative registry population. RESULTS: A total of 7 studies involving 24 246 patients were analyzed. Within this patient cohort, 4771 individuals underwent TCAR, 12 350 underwent CEA, and 7125 patients underwent CAS. Compared with CAS, TCAR was associated with a similar rate of stroke or transient ischemic attack (OR, 0.77 [95% CI, 0.33-1.82]) and myocardial infarction (OR, 1.29 [95% CI, 0.83-2.01]) but lower mortality (OR, 0.42 [95% CI, 0.22-0.81]). Compared with CEA, TCAR was associated with a higher rate of stroke or transient ischemic attack (OR, 1.26 [95% CI, 1.03-1.54]) but similar rates of myocardial infarction (OR, 0.9 [95% CI, 0.64-1.38]) and mortality (OR, 1.35 [95% CI, 0.87-2.10]). CONCLUSIONS: Although CEA has traditionally been considered superior to stenting for symptomatic carotid stenosis, TCAR may have some advantages over CAS. Prospective randomized trials comparing the 3 modalities are needed.

FLAIR signal intensity ratio predicts small subcortical infarct early neurologic deterioration: a cross-sectional study.

PURPOSE: Prior studies have used the fluid-attenuated inversion recovery sequence signal intensity ratio (FLAIR-SIR) to predict those with an incomplete infarct that may safely receive acute thrombolytics. Clinical early neurologic deterioration (END) of small subcortical infarcts (SSIs) is suspected to occur due to delayed infarct completion. We aimed to understand if a lower FLAIR-SIR, suggestive of an incomplete infarct, would have a higher likelihood of SSI-related END. METHODS: A cross-sectional retrospective study was performed of those with an acute SSI (anterior or posterior circulation) without significant parent vessel steno-occlusive disease. END was defined as a new or worsened disabling neurologic deficit during the index hospitalization. Standard-of-care brain MRIs were reviewed from the hospitalization, and a FLAIR-SIR cutoff of ≤ 1.15 was used based on prior studies. Adjusted logistic regression models were used for analysis. RESULTS: We identified 252 patients meeting inclusion criteria: median (IQR) age 68 (12) years, 38.5% (97/252) female, and 11% (28/252) with END. Tobacco use was more common in those without END (32%) compared with END (55%, p = 0.03). In adjusted analyses, a FLAIR-SIR cutoff of ≤ 1.15 yielded an odds ratio of 2.8 (95% CI 1.23-6.13, p = 0.012) of early neurological deterioration. CONCLUSION: Those with a FLAIR-SIR ≤ 1.15 are nearly threefold more likely to develop SSI-related END.

Guided Endodontic Surgery: A Narrative Review.

Background and objectives: Endodontic surgery has evolved over the last two decades. The use of state-of-the-art guided endodontic surgical procedures produces a predictable outcome in the healing of lesions of endodontic origin. The main objective of this review paper is to define and characterize guided surgical endodontics as well as its benefits and drawbacks by reviewing the most recent relevant scientific literature. Methods: A literature search was conducted using multiple databases comprising of MEDLINE (via PubMed), EMBASE, and Web of Science. The terms used for the search were 'guided endodontics', 'surgical endodontics', and 'endodontic microsurgery'. Results: In total, 1152 articles were obtained from the analysis of the databases. Unrelated articles from the available full text of 388 articles were excluded. A total of 45 studies were finally included in the review. Conclusions: Surgical-guided endodontics is a relatively new area of study that is still maturing. It has many applications such as root canal access and localization, microsurgical endodontics, endodontic retreatment, and glass fiber post removal. Additionally, it does not matter how experienced the operator is; the procedure can be completed for the patient in less time and provides greater accuracy and safety than conventional endodontics.

Pulmonary hypertension associated with cardiopulmonary bypass and cardiac surgery.

BACKGROUND AND AIM: Pulmonary hypertension (PH) is frequently associated with cardiovascular surgery and is a common complication that has been observed after surgery utilizing cardiopulmonary bypass (CPB). The purpose of this review is to explain the characteristics of PH, the mechanisms of PH induced by cardiac surgery and CPB, treatments for postoperative PH, and future directions in treating PH induced by cardiac surgery and CPB using up-to-date findings. METHODS: The PubMed database was utilized to find published articles. RESULTS: There are many mechanisms that contribute to PH after cardiac surgery and CPB which involve pulmonary vasomotor dysfunction, cyclooxygenase, the thromboxane A2 and prostacyclin pathway, the nitric oxide pathway, inflammation, and oxidative stress. Furthermore, there are several effective treatments for postoperative PH within different types of cardiac surgery. CONCLUSIONS: By possessing a deep understanding of the mechanisms that contribute to PH after cardiac surgery and CPB, researchers can develop treatments for clinicians to use which target the mechanisms of PH and ultimately reduce and/or eliminate postoperative PH. Additionally, learning about the most up-to-date studies regarding treatments can allow clinicians to choose the best treatments for patients who are undergoing cardiac surgery and CPB.

Computer simulation of a backscattered X-ray fluorescence system.

An EGSnrc user code is developed to simulate a backscattered geometry in vivo x-ray fluorescence system for the measurement of platinum concentration in head and neck tumours. The user code is fundamentally based on a previous study which used the EGS4 Monte Carlo code. The new user code, which we have developed in this study, has new improvements which made it able to simulate the process of photon transportation through the different components of the modelled x-ray fluorescence system. The simulation process included modelling of the photon source, collimators, phantoms and detector. Simulation results were compared and evaluated against x-ray fluorescence data obtained experimentally from an existing system developed by the Swansea In vivo Analysis and Cancer Research Group. In addition, simulation results of this study were also compared with our previous study in which the EGS4 user code was used. Comparison between results has shown that the new EGSnrc user code was able to reproduce the spectral shape obtained using the experimental x-ray fluorescence system. The area under the Compton peak differs by 2.5% between the experimental measurement and the EGSnrc simulation. Similarly, the area under the two Pt Kα peaks differs by 2.3% and 2.2%.

The Effect of Early Orthodontic Treatment on Long-Term Stability of Class II Malocclusions.

Background: Class II malocclusions are a common dental issue characterized by the misalignment of the upper and lower teeth. Early orthodontic treatment is often considered to correct these malocclusions, but its long-term effectiveness remains unclear. Materials and Methods: In this study, we examined the impact of early orthodontic treatment on the long-term stability of Class II malocclusions. We conducted a retrospective analysis of dental records from a sample of 150 patients who had received early orthodontic treatment for Class II malocclusions. The treatment involved braces and other orthodontic appliances. We compared their dental measurements before and after treatment, with a follow-up period of 5 years. Results: Our analysis revealed that the early orthodontic treatment led to a significant improvement in the alignment of upper and lower teeth, as indicated by a reduction in the overjet (the horizontal distance between upper and lower incisors). The mean overjet reduction was 3.2 millimeters. Furthermore, the Angle's Class II molar relationship was corrected in 80% of the cases. Conclusion: Early orthodontic treatment for Class II malocclusions demonstrated positive long-term stability, as evidenced by a reduction in overjet and improvement in molar relationships.

De-Biased Disentanglement Learning for Pulmonary Embolism Survival Prediction on Multimodal Data.

Health disparities among marginalized populations with lower socioeconomic status significantly impact the fairness and effectiveness of healthcare delivery. The increasing integration of artificial intelligence (AI) into healthcare presents an opportunity to address these inequalities, provided that AI models are free from bias. This paper aims to address the bias challenges by population disparities within healthcare systems, existing in the presentation of and development of algorithms, leading to inequitable medical implementation for conditions such as pulmonary embolism (PE) prognosis. In this study, we explore the diverse bias in healthcare systems, which highlights the demand for a holistic framework to reducing bias by complementary aggregation. By leveraging de-biasing deep survival prediction models, we propose a framework that disentangles identifiable information from images, text reports, and clinical variables to mitigate potential biases within multimodal datasets. Our study offers several advantages over traditional clinical-based survival prediction methods, including richer survival-related characteristics and bias-complementary predicted results. By improving the robustness of survival analysis through this framework, we aim to benefit patients, clinicians, and researchers by enhancing fairness and accuracy in healthcare AI systems.

Exploring an Association between Body Mass Index and Oral Health-A Scoping Review.

BACKGROUND: Basal metabolic index (BMI) is a unique anthropometric indicator used to define the relative amount of body fat on an individual's frame. There are many diseases and conditions associated with obesity and underweight. Recent research trials suggest that there is a significant association between oral health indicators and BMI as both are attributed to common risk factors such as dietary, genetic, socioeconomic, and lifestyle issues. OBJECTIVES: The main objective of this review paper is to emphasize the association between BMI and oral health with available literature evidence. METHODOLOGY: A literature search was conducted using multiple databases comprising of MEDLINE (via PubMed), EMBASE, and Web of Science. The terms used for the search were "body mass index", "periodontitis", "dental caries", and "tooth loss". RESULTS: In total, 2839 articles were obtained from the analysis of the databases. Unrelated articles from the available full text of 1135 articles were excluded. The main reasons for excluding the articles were: they were dietary guidelines and policy statements. A total of 66 studies were finally included in the review. CONCLUSION: The presence of dental caries, periodontitis and tooth loss may be associated with a higher BMI or obesity, whereas, improved oral health might be associated with lower BMI. Promoting general and oral health should be a hand in hand feature, as common risk factors can be embattled.

Borderzone Infarcts and Recurrent Cerebrovascular Events in Symptomatic Intracranial Arterial Stenosis: A Systematic Review and Meta-Analysis.

BACKGROUND AND PURPOSE: Intracranial arterial stenosis (ICAS)-related stroke occurs due to three primary mechanisms with distinct infarct patterns: (1) borderzone infarcts (BZI) due to impaired distal perfusion, (2) territorial infarcts due to distal plaque/thrombus embolization, and (3) plaque progression occluding perforators. The objective of the systematic review is to determine whether BZI secondary to ICAS is associated with a higher risk of recurrent stroke or neurological deterioration. METHODS: As part of this registered systematic review (CRD42021265230), a comprehensive search was performed to identify relevant papers and conference abstracts (with ≥20 patients) reporting initial infarct patterns and recurrence rates in patients with symptomatic ICAS. Subgroup analyses were performed for studies including any BZI versus isolated BZI and those excluding posterior circulation stroke. The study outcome included neurological deterioration or recurrent stroke during follow-up. For all outcome events, corresponding risk ratios (RRs) and 95% confidence intervals (95% CI) were calculated. RESULTS: A literature search yielded 4,478 records with 32 selected during the title/abstract triage for full text; 11 met inclusion criteria and 8 studies were included in the analysis (n=1,219 patients; 341 with BZI). The meta-analysis demonstrated that the RR of outcome in the BZI group compared to the no BZI group was 2.10 (95% CI 1.52-2.90). Limiting the analysis to studies including any BZI, the RR was 2.10 (95% CI 1.38-3.18). For isolated BZI, RR was 2.59 (95% CI 1.24-5.41). RR was 2.96 (95% CI 1.71-5.12) for studies only including anterior circulation stroke patients. CONCLUSION: This systematic review and meta-analysis suggests that the presence of BZI secondary to ICAS may be an imaging biomarker that predicts neurological deterioration and/or stroke recurrence.

Lack of association between fat mass and obesity-associated genetic variant (rs8050136) and type 2 diabetes mellitus.

OBJECTIVES: To study the genotype and allele frequency of the fat mass and obesity-associated (FTO) rs8050136 A>C genetic variant and investigate its association with type 2 diabetes mekkitus (T2DM) parameters. METHODS: This study was carried out on 118 diabetic patients and 106 healthy individuals (control) from Prince Mohammed bin Abdulaziz Hospital, Al Madinah Al Munawarah, Saudi Arabia. The TaqMan single-nucleotide polymorphism (SNP)genotyping assay was used for rs8050136 genotyping. RESULTS: The frequency of the genotype AA was the same among T2DM and healthy control groups (21%). However, the frequency of genotype CC was 19.5% in T2DM patients and 24.5% in control individuals. There was no significant association between FTO SNP rs8050136 and an increased risk of T2DM. Furthermore, there was no association between the risk AA genotype and fasting blood glucose (p=0.092), glycated hemoglobin (p=0.177), or body mass index (p=0.561). CONCLUSION: Our findings show that the FTO rs8050136 A>C variant is not associated with T2DM in the Saudi population.

High Seroprevalence of SARS-CoV-2 IgG and RNA among Asymptomatic Blood Donors in Makkah Region, Saudi Arabia.

The gold-standard approach for diagnosing and confirming Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2) infection is reverse transcription-polymerase chain reaction (RT-PCR). This method, however, is inefficient in detecting previous or dormant viral infections. The presence of antigen-specific antibodies is the fingerprint and cardinal sign for diagnosis and determination of exposure to infectious agents including Corona virus disease-2019 (COVID-19). This cross-sectional study examined the presence of SARS-CoV-2 spike-specific immunoglobulin G (IgG) among asymptomatic blood donors in Makkah region. A total of 4368 asymptomatic blood donors were enrolled. They were screened for spike-specific IgG using ELISA and COVID-19 RNA by real-time PCR. COVID-19 IgG was detected among 2248 subjects (51.5%) while COVID-19-RNA was detected among 473 (10.8%) subjects. The IgG frequency was significantly higher among males and non-Saudi residents (p < 0.001 each) with no significant variation in IgG positivity among blood donors with different blood groups. In addition, COVID-19 RNA frequency was significantly higher among donors below 40-years old (p = 0.047, χ2 = 3.95), and non-Saudi residents (p = 0.001, χ2 = 304.5). The COVID-19 IgG levels were significantly higher among the RNA-positive donors (p = 001), and non-Saudi residents (p = 0.041), with no variations with age or blood group (p > 0.05). This study reveals a very high prevalence of COVID-19 IgG and RNA among asymptomatic blood donors in Makkah, Saudi Arabia indicating a high exposure rate of the general population to COVID-19; particularly foreign residents. It sheds light on the spread on COVID-19 among apparently healthy individuals at the beginning of the pandemic and could help in designing various control measures to minimize viral spread.

Natural immunity to influenza A and B among Saudi blood donors in Al Madinah Al Munawarah, Saudi Arabia.

OBJECTIVES:  To investigate the seroprevalence of influenza viruses (A and B) among blood donors in Kingdom of Saudi Arabia. Methods: The present investigation was conducted between April 2019 and July 2019. Participants were healthy adults recruited from the central blood bank Al Madinah Al Munawarah, Kingdom of Saudi Arabia. Immunoglobulin G (IgG) levels against influenza A and B were measured in serum samples using ELISA. RESULTS: The results showed that 29.2% of the sample had significant concentrations of influenza A IgG antibody, whereas 38.6% had significant concentrations of influenza B IgG antibody. A strong correlation was found between the levels of influenza A and influenza B antibodies (r=0.708, p less than 0.001). The number of individuals identified as negative for influenza A IgG antibody increased with age (p less than 0.01). In addition, no correlations were identified between influenza A IgG and influenza B IgG and body mass index (BMI), (p greater than 0.05). Finally, linear regression analysis showed that the level of influenza A antibody can be predicted by age (p less than 0.05) and body mass index (BMI) (p less than 0.05). CONCLUSION:  Approximately one-third of Saudi Arabian adults presented significant levels of influenza A and B antibodies in our study. Demographic factors, including age and BMI, might contribute to influenza A antibody levels.

Optimized Polyethylene Glycolylated Polymer-Lipid Hybrid Nanoparticles as a Potential Breast Cancer Treatment.

PURPOSE: The aim of this work is to optimize a polyethylene glycolated (PEGylated) polymer-lipid hybrid nanoparticulate system for the delivery of anastrozole (ANS) to enhance its biopharmaceutical attributes and overall efficacy. METHODS: ANS loaded PEGylated polymer-lipid hybrid nanoparticles (PLNPs) were prepared by a direct emulsification solvent evaporation method. The physical incorporation of PEG was optimized using variable ratios. The produced particles were evaluated to discern their particle size and shape, zeta-potential, entrapment efficiency, and physical stability. The drug-release profiles were studied, and the kinetic model was analyzed. The anticancer activity of the ANS PLNPs on estrogen-positive breast cancer cell lines was determined using flow cytometry. RESULTS: The prepared ANS-PLNPs showed particle sizes in the range of 193.6 ± 2.9 to 218.2 ± 1.9 nm, with good particle size uniformity (i.e., poly-dispersity index of around 0.1). Furthermore, they exhibited relatively low zeta-potential values ranging from -0.50 ± 0.52 to 6.01 ± 4.74. The transmission electron microscopy images showed spherical shape of ANS-PLNPs and the compliance with the sizes were revealed by light scattering. The differential scanning calorimetry DSC patterns of the ANS PLNPs revealed a disappearance of the characteristic sharp melting peak of pure ANS, supporting the incorporation of the drug into the polymeric matrices of the nanoparticles. Flow cytometry showed the apoptosis of MCF-7 cell lines in the presence of ANS-PLNPs. CONCLUSION: PEGylated polymeric nanoparticles presented a stable encapsulated system with which to incorporate an anticancer drug (ANS) with a high percentage of entrapment efficiency (around 80%), good size uniformity, and induction of apoptosis in MCF-7 cells.

Development of a computer code using the EGS4 Monte Carlo simulation system to evaluate the response of a NaI(Tl) detector to photons with energies below 300 keV.

In this paper, the EGS4 Monte Carlo simulation system was used to develop a computer code for a study of the response of a NaI(Tl) detector exposed to gamma-rays with energies below 300 keV. This study comprised registration of the spectra of the incident rays and determination of the photo peaks. In addition, the probability of the K X-ray escape from a NaI(Tl) crystal and its dependence on the detector shape and volume were considered. The results of the Monte Carlo simulation are in good agreement with the experimental data (the estimated discrepancy is below 5%). This demonstrates a high efficiency of the used simulation code in quantifying the physical parameters that are difficult to evaluate by experimental methods.

Measurements of indoor gamma radiation dose in At-Taif city, Saudi Arabia using CaSO4:Dy (TLD-900).

This paper describes measurements of indoor gamma radiation dose in At-Taif city, Kingdom of Saudi Arabia. CaSO(4):Dy thermoluminescence dosemeters were used for the detection of gamma radiation in 250 houses within the city. The values of indoor gamma radiation dose rate measured ranged between 90 and 221 nGy h(-1) for the time interval from September 2002 to September 2003. The measured dose varied with the type of house and season of the year. The highest average value 192 +/- 7 nGy h(-1) was measured inside apartments made of cement and brick (157-221 nGy h(-1)), and the lowest average value 92 +/- 6 nGy h(-1) in mud houses (58-117 nGy h(-1)). Intermediate values 154 +/- 5 nGy h(-1) (128-177 nGy h(-1)) and 167 +/- 9 nGy h(-1) (144-185 nGy h(-1)) were observed in large halls and villas, respectively. The average indoor gamma radiation dose rate received by the population of At-Taif city is 138 nGy h(-1) and its corresponding annual dose is 1211 muGy y(-1). The calculated mean effective dose to At-Taif city population, assuming an indoor occupancy factor of 80%, is 970 muSv y(-1).

Measurements of environmental terrestrial gamma radiation average dose rate in three mountainous locations in the western region of Saudi Arabia.

This paper describes measurements of external gamma radiation average dose rate from terrestrial gamma rays 1 m above the ground in three different mountainous locations in the western region of the Kingdom of Saudi Arabia. These locations are, At-Taif city, Al-Hada village and Ash-Shafa village. CaSO(4):Dy (TLD-900) thermoluminescence dosemeters were used for the detection of terrestrial gamma radiation at 40 different places in the three locations. The values of terrestrial gamma radiation average dose rate measured ranged between 14 and 279 nG h(-1) for the time interval from June 2001 to June 2002. The measured average dose rate varied with the season of the year. The gamma radiation average dose rates were 468, 541 and 781 microGy y(-1) for At-Taif city, Al-Hada village and Ash-Shafa village, respectively. The corresponding average effective dose rates for the three locations were 94, 108 and 156 microSv y(-1), respectively.

Comparison of the influence of nonpreserved oxybuprocaine and a preserved artificial tear (thera tears) on human corneal thickness measured by two pachymeters.

PURPOSE: To compare the effect of nonpreserved oxybuprocaine and preserved artificial tears on central corneal thickness (CCT) obtained by 2 pachymeters. METHODS: In this prospective, placebo-controlled study, involving a random sample of 100 eyes of 50 subjects, aged 24±2.3 years, CCT readings were obtained in 2 separate sessions with the Topcon SP-3000P and ultrasound pachymetry (USP), respectively, before, 5 and 10 min after instillation of a drop each of either oxybuprocaine hydrochloride (oxybuprocaine HCl) (group 1) or carboxymethylcellulose sodium, thera tears (group 2), and placebo. RESULTS: The baseline mean CCT for SP-3000P was 509±38 µm and 542±36 µm for USP. No statistical significant differences between baseline CCTs (P>0.05 for both devices) in both groups. In both group experimental eyes, neither SP-3000P nor USP-measured CCTs varied significantly from the control eyes at 5 (P>0.05) and 10 (P>0.05) mins postinstillation of drops in both sessions. In group one, the 95% confidence intervals (CIs) for the SP-3000P CCTs were similar at 5 (-16 to 17 µm) and 10 min (-16 to 17 µm), but in the USP-measured CCTs, it was wider at 10 min (-41 to 46 µm) than at 5 min (-30 to 41 µm) postinstillation. In group two, the 95% CIs at 5 and 10 mins postinstillation, respectively, ranged between -20 and 47 µm, -21 and 43 µm (SP-3000P) and -29 and 23 µm, -26 and 23 µm (USP). Within groups and between groups, variations in CCT were similar at both times intervals in all comparisons. CONCLUSION: Although oxybuprocaine HCl and thera tears consistently did not affect the mean CCT obtained by both devices at both time intervals, variation in SP-3000P measured CCT was more consistent in both sessions and narrower in relation to USP-measured CCT. It may be reasonable to suggest that measurements of CCT in normal patients be taken before examinations requiring instillation of anesthetics or such measurements when obtained postinstillation of either oxybuprocaine or preserved artificial tears be interpreted with caution.

Measurements of environmental terrestrial gamma radiation dose rate in three mountainous locations in the western region of Saudi Arabia.

This paper describes measurements of external gamma radiation dose rate from terrestrial gamma-rays 1m above the ground in three different mountainous locations in the western region of the Kingdom of Saudi Arabia. These locations are At-Taif city, Al-Hada village, and Ash-Shafa village. CaSO4:Dy (TLD-900) thermoluminescent dosimeters were used for the detection of terrestrial gamma radiation at 40 different places in the three locations. The values of terrestrial gamma radiation dose rate measured ranged between 14 and 279 nGy h(-1) for the time interval from June 2001 to June 2002. The measured dose rate varied with the season of the year. The average gamma radiation dose rates were 468, 541, and 781 microGy y(-1) for At-Taif city, Al-Hada village, and Ash-Shafa village, respectively. The corresponding average absorbed doses to the population of the three locations were 328, 379, and 547 microSv y(-1), respectively. The quality factor of 0.7 SvG y(-1) was applied in the calculations of the absorbed dose to humans.

Blood flow in the external auditory canal and tympanic membrane as assess by laser doppler blood flowmetry

INTRODUCTION: Procedures within the external meatus and tympanum constitute a large part of otological surgery. Successful healing after procedures on the tympanic membrane will in large part be dependent on the integrity of local blood flow. However, there appear to have been relatively few studies investigating blood flow in the external auditory meatus and tympanum in normal subjects and those with conditions requiring surgery, e.g. tympanoplasty. The aim of this study is to obtain such data using Laser Doppler Blood Flowmetry. METHOD: Control volunteers (n = 30) and patients requiring tympanoplasty (n = 20) were recruited for the study. Laser Doppler Blood Flowmetry was performed in all patients using a commercially available system (Periflux 5000, Perimed AB, Sweden) at four sites: (1) preauricular skin; (2) cartilaginous ear canal; (3) bony ear canal; and (4) tympanic membrane. Mesotympanic temperature was also measured using a Braun Infrared thermometer. Blood flow (flux) was measured as RBC density 'speed following internal calibration. RESULTS: Analysis revealed that in both the control subjects and pretympanoplasty patients, the ranking of blood flow at the sites was 3, 2, 1 and 4 (highest to lowest). Comparing matched sites, there were no significant differences between the two groups. The amplitude of flow was not found to be correlated with mesotympanic temperature. CONCLUSION: Grafts applied to repair perforations of the tympanic membrane are likely to obtain the majority of their blood supply from the bony external auditory meatus rather than that tympanic membrane. Further studies are ongoing to define local blood flow patterns in order to optimize the results of tympanoplasty.