Lebanon: business as usual.
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Adolescent↗
Biomedical subjects
K Lee
Publications and source records attributed to K Lee.
Formation, manipulation, and elasticity measurement of a nanometric column of water molecules.
Nanometer-sized columns of condensed water molecules are formed by an atomic-resolution force microscope operated in ambient conditions. An unusual stepwise decrease of the force gradient associated with the ultrathin water bridge in the tip-substrate gap is observed during its stretch, exhibiting regularity in step heights (approximately 0.5 N/m) and plateau lengths (approximately 1 nm). Such "quantized" elasticity is indicative of an atomic-scale stick slip at the tip-water interface. A thermodynamic-instability-induced rupture of the water meniscus (5 nm long and 2.6 nm wide) is also found. This work opens a high-resolution study of the structure and interface dynamics of a nanometric aqueous column.
Micromanipulation↗
The accuracy of historical height loss for the detection of vertebral fractures in postmenopausal women.
Historical height loss (HHL) can be calculated as the difference between a patient's tallest recalled height (TRH) and the current measured height (MH). We have examined the accuracy of HHL as a clinical test for the detection of prevalent vertebral fractures. Subjects were postmenopausal women aged 50 or older who had been referred for specialist assessment of osteoporosis risk (n=323; average age 66.0+/-9.2 years; range 50-92 years). MH was determined using a wall-mounted stadiometer. The presence of prevalent vertebral fractures was assessed by radiographic morphometry, with fracture defined as a vertebral height ratio<0.8. The positive likelihood ratio (LR+) for fracture was relatively flat until HHL>6.0 cm. With HHL from 6.1 to 8.0 cm, the LR+ was 2.8 [95% confidence interval (95%CI), 1.3, 6.0]. When HHL was >8.0 cm, the LR+ was 9.8 (95% CI, 3.0, 31.8). The area under the receiver operating characteristics curve for the ability of HHL to detect fracture was 0.66 (95% CI, 0.59, 0.72). At HHL>6.0 cm, sensitivity was 30% (95% CI, 22, 37%), and specificity was 94% (95% CI, 90, 97%). The positive predictive value was relatively low across a range of theoretical prevalence, rising above 80% only at very high prevalence rates (>50%). In contrast, the negative predictive value was high at the prevalence rates seen in most clinical practice, and dropped below 80% only when the prevalence exceeded 25%. This study shows that HHL 6.0 cm should have spine radiographs to examine for the presence of vertebral fractures.
Age Factors↗
Predictors of prescription of morphine for severe cancer pain by physicians in Korea.
BACKGROUND: This study was undertaken to identify predictors of the prescription of strong opioids, which are important for the management of severe cancer pain, by Korean physicians. METHODS: A questionnaire based on a hypothetical case designed to assess the prescription of morphine by physicians was administered to 800 specialists in the Korea Cancer Association, of whom 147 (18.4%) responded, and to 2200 specialists in the Korean Academy of Family Medicine, of whom 388 (17.6%) responded. We used a multidimensional approach to identify the predictors of prescription of morphine by physicians. RESULTS: In the hypothetical case scenario, only 16.5% of the respondents stated that they would prescribe morphine for severe cancer pain. Multiple logistic regression analysis showed that physicians with a positive attitude regarding opioid addiction [odds ratio (OR) 2.62; 95% confidence interval (CI) 1.54-4.46], experience of pain assessment (OR 2.09; 95% CI 1.13-3.87), recent residency training (OR 2.27; 95% CI 1.30-4.0) and positive self-evaluation as an oncology specialist (OR 2.60; 95% CI 1.41-4.78) were more likely to prescribe morphine. None of the 13 variables in the knowledge dimension significantly predicted prescription of morphine for severe cancer pain. CONCLUSIONS: The results of the survey suggest that we need to develop strategies to develop a positive attitude toward opioids, to increase experience in pain assessment and to improve cancer pain management training among Korean physicians.
Adult↗
Photochemical modification and patterning of polymer surfaces by surface adsorption of photoactive block copolymers.
We report a simple photolithographic approach for the creation and micropatterning of chemical functionality on polymer surfaces by use of surface-active block copolymers that contain protected photoactive functional groups. The block copolymers self-assemble at the substrate-air interface to generate a surface that is initially hydrophobic with low surface tension but that can be rendered hydrophilic and functional by photodeprotection with UV radiation. The block copolymer employed, poly(styrene-b-tert butyl acrylate), segregates preferentially to the surface of a polystyrene substrate because of the low surface tension of the polyacrylate blocks. The strong adsorption of block copolymers causes a bilayer structure to form presenting a photoactive polyacrylate layer at the surface. In the example described, the tert-butyl ester groups on the polyacrylate blocks are deprotected by exposure to UV radiation in the presence of added photoacid generators to form surface carboxylic acid groups. Surface micropatterns of carboxylic acid groups are generated by UV exposure through a contact mask. The success of surface chemical modification and pattern formation is demonstrated by X-ray photoelectron spectroscopy and contact angle measurements along with imaging by optical and fluorescence microscopy methods. The resultant chemically patterned surfaces are then used to template patterns of various biomolecules by means of selective adsorption, covalent bonding and molecular recognition mechanisms. The surface modification/patterning concept can be applied to virtually any polymeric substrate because protected functional groups have intrinsically low surface tensions, rendering properly designed block copolymers surface active in almost all polymeric substrates.
Acrylates↗
Application of an enzyme-linked immunosorbent assay for the analysis of paraquat in human-exposure samples.
Paraquat is a toxic quaternary ammonium compound used as an herbicide around the world. Easy, fast, and inexpensive but sensitive methods are needed to study the effects of long-term, low-level exposure of paraquat on human health. An enzyme-linked immunosorbent assay (ELISA) was used for quantification of paraquat in urine and air-filter samples collected in a human-exposure study among farm workers in Costa Rica. A sample pretreatment consisted of removal of interfering substances using solid-phase extraction resin columns. The precision and accuracy of the method were tested using duplicate spiked urine samples. The correlation between results for blind samples obtained using ELISA and liquid chromatography-mass spectrometry was significant (R2 = 0.945 and 0.906 for spiked and field samples, respectively). With an LOQ of 2 ng mL(-1), this ELISA method was able to distinguish the exposed from the nonexposed farm workers. For the air-filter analysis, paraquat was extracted by 9 M H2SO4 at 60 degrees C for 12 hours, and the results obtained by ELISA showed good correlation (R2 = 0.918) with the spectrophotometric (256 nm) measurements. Paraquat in acid-stabilized urine samples was very stable, and no significant losses were detected during a 3-month storage at room temperature, at 4 degrees C, or at -20 degrees C.
Air Pollutants↗
Noradrenergic receptor mRNA expression in adult rat superficial dorsal horn and dorsal root ganglion neurons.
Noradrenaline (NAdr) has well documented analgesic actions at the level of the spinal cord. Released from bulbospinal projections onto superficial dorsal horn (SDH) neurons, NAdr modulates the excitability of these neurons through the activation of alpha1, alpha2 or beta adrenoceptors. This study utilised in situ hybridisation to determine the specific expression of adrenoceptors within adult rat lumbar SDH and dorsal root ganglion (DRG) neurons, and reports the presence of alpha1A, alpha1B, alpha2B, beta1 and beta2 adrenoceptor mRNA within SDH neurons, and the presence of alpha1A, alpha1B and alpha2C adrenoceptor mRNA within DRG neurons. The present study provides an insight into the modulation of sensory processing at the level of the spinal cord following adrenoceptor activation.
Animals↗
Successful use of recombinant human thyrotropin in the therapy of pediatric well-differentiated thyroid cancer.
Recombinant human TSH (rhTSH) is increasingly employed in stimulating radioiodine (131I) uptake in adults with well-differentiated thyroid cancer (WDTC) for diagnostic scanning, and preliminary evidence suggests that it may have a role in radioactive iodine therapy as well. However, the safety and efficacy of rhTSH in children have not been determined. We report a case of a 13-yr-old boy presenting with metastatic papillary thyroid cancer. After total thyroidectomy, his serum thyroglobulin (Tg) was 302 ng/ml (3.7-49.3) with negative antibodies. A diagnostic whole body scan (WBS) demonstrated multiple foci of uptake in the neck, thyroid bed and chest. His serum TSH only increased to 14.2 microU/ml (0.3-4.7) upon thyroid hormone withdrawal. Therefore, the patient was given 0.9 mg rhTSH every 24 h for two consecutive days and treated with 102 mCi 131I 24 h after the last rhTSH injection. Six months later, the patient was again conditioned with rhTSH and treated with an additional 150 mCi 131I. This treatment effectively reduced his tumor load with his most recent (10 months after the second ablation) serum Tg measuring 19.3 ng/ml. This case highlights the safety and effectiveness of rhTSH stimulated radioablation in pediatric WDTC, and proposes to invite controlled studies to further investigate pediatric rhTSH use, particularly in patients in whom thyroid hormone withdrawal is not a viable option.
Adolescent↗
The FLUKA code: new developments and application to 1 GeV/n iron beams.
The modeling of ion transport and interactions in matter is a subject of growing interest, driven by the continuous increase of possible application fields. These include hadron therapy, dosimetry, and space missions, but there are also several issues involving fundamental research, accelerator physics, and cosmic ray physics, where a reliable description of heavy ion induced cascades is important. In the present work, the capabilities of the FLUKA code for ion beams will be briefly recalled and some recent developments presented. Applications of the code to the simulation of therapeutic carbon, nitrogen and oxygen ion beams, and of iron beams, which are of direct interest for space mission related experiments, will be also presented together with interesting consideration relative to the evaluation of dosimetric quantities. Both applications involve ion beams in the AGeV range.
Carbon↗
Investigation of a nosocomial outbreak of Acinetobacter baumannii producing PER-1 extended-spectrum beta-lactamase in an intensive care unit.
We investigated an outbreak of Acinetobacter baumannii in an adult intensive care unit of Kosin University Gospel Hospital in Busan, Republic of Korea. The outbreak involved 10 cases of infection by A. baumannii producing PER-1 extended-spectrum beta-lactamase over a seven-month period, and was caused by a single pulsed-field gel electrophoresis clone. The epidemic isolates were characterized by slight synergy between clavulanic acid and cefepime. Isoelectric focusing of crude bacterial extracts detected two nitrocefin-positive bands with pI values of 8.0 and 5.3. Polymerase chain reaction amplification and characterization of the amplicons by restriction analysis and direct sequencing indicated that the epidemic isolates carried a bla(PER-1) determinant. The epidemic isolates were characterized by a multidrug-resistant phenotype that remained unchanged over the outbreak, including penicillins, beta-lactam/beta-lactamase inhibitor, extended-spectrum cephalosporins and monobactams. Isolation of infected patients and appropriate carbapenem therapy were successful in ending the outbreak. Our report indicates that the bla(PER-1) resistance determinant may become an emerging therapeutic problem.
Acinetobacter Infections↗
Access to appropriate information on HIV is important in maximizing the acceptance of the antenatal HIV antibody test.
The universal HIV antibody testing programme was implemented in Hong Kong in September 2001. A survey on acceptance of the test was conducted in the territory's maternal and child health centres in a two-month period. The response rate was 98.2% and 2,669 valid questionnaires were analysed. Seventy per cent (n=1,825) of the respondents indicated their acceptance of the test. A significant association was noted between clients' acceptance and access to HIV information (adjusted odds ratio (OR)=10.45, 95% confidence interval (CI)=6.33-17.26) by means of posters, pamphlets, videos and group talks. Perceived benefits and health care workers' recommendation were the main reported reasons for acceptance, whereas no or low perceived susceptibility was the main reason for refusal. Acceptance was also positively correlated with level of education (adjusted OR=3.99, 95% CI=2.15-7.43) and HIV knowledge (adjusted OR=3.61, 95% CI=2.19-5.93). A high uptake rate (99.6%) reflects that most had the test done eventually despite some initial uncertainty. It is concluded that access to appropriate HIV information was important to maximize the acceptance of the programme.
Adolescent↗
Localization of a novel autosomal recessive non-syndromic hearing impairment locus DFNB55 to chromosome 4q12-q13.2.
Hereditary hearing impairment (HI) is the most genetically heterogeneous trait known in humans. So far, 54 autosomal recessive non-syndromic hearing impairment (ARNSHI) loci have been mapped, and 21 ARNSHI genes have been identified. Here is reported the mapping of a novel ARNSHI locus, DFNB55, to chromosome 4q12-q13.2 in a consanguineous Pakistani family. A maximum multipoint LOD score of 3.5 was obtained at marker D4S2638. The region of homozygosity and the 3-unit support interval are flanked by markers D4S2978 and D4S2367. The region spans 8.2 cm on the Rutgers combined linkage-physical map and contains 11.5 Mb. DFNB55 represents the third ARNSHI locus mapped to chromosome 4.
Chromosome Mapping↗
Mortality risk factors of Acinetobacter baumannii bacteraemia.
BACKGROUND: Acinetobacter baumannii is one of the most important nosocomial pathogens, and its multiple antibiotic resistance has emerged as an obstacle in the treatment of these infections worldwide. AIMS: To identify risk factors of mortality for A. baumannii bacteraemia. METHODS: A retrospective cohort study of 72 patients with significant A. baumannii bacteraemia was conducted to evaluate risk factors for mortality. RESULTS: The median age of the 72 enrolled patients was 48 years, 96% of the cases were hospital-acquired, and the bacteraemia-related mortality rate was 29% (21 of 72 patients). Univariate analysis revealed that the risk factors for mortality included: an elevated acute physiology and chronic health evaluation (APACHE II) score, receipt of in vitro ineffective definitive antimicrobial therapy, in vitro A. baumannii resistance to cefoperazone/ sulbactam, neutropenia, and presentation with septic shock. Multivariate analysis reveals that the independent risk factors for mortality are neutropenia and elevated APACHE II scores. CONCLUSION: Risk factors such as neutropenia and elevated APACHE II scores are found to be associated with higher mortality rates of A. baumannii bacteraemia. Further study is necessary for the determination of optimal strategies for both the prevention and treatment of these infections.
Acinetobacter Infections↗
Greater beneficial effects of visceral fat reduction compared with subcutaneous fat reduction on parameters of the metabolic syndrome: a study of weight reduction programmes in subjects with visceral and subcutaneous obesity.
AIMS: To evaluate the effect of weight reduction on parameters of the metabolic syndrome in obese patients according to their pattern of abdominal fat distribution. METHODS: A longitudinal intervention study, consisting of a 12-week weight reduction programme, including lifestyle modification and adjuvant appetite suppressant, in 38 subjects with visceral obesity and 47 subjects with subcutaneous obesity. Visceral, subcutaneous and total adipose tissue areas were determined by CT scan at the level of L4-L5. Parameters for components of the metabolic syndrome were measured before and after weight reduction. RESULTS: Reductions in body weight, BMI and subcutaneous adipose tissue area were greater in the subcutaneous than in the visceral obesity group. In contrast, changes in fasting plasma glucose, insulin, and HOMA score were higher in the visceral than in the subcutaneous obesity group. Changes in visceral adipose tissue area were significantly related to changes in fasting plasma glucose, triglycerides and HOMA score. CONCLUSIONS: Visceral fat reduction induced greater beneficial effects on parameters of the metabolic syndrome than subcutaneous fat reduction. Evaluation of changes in abdominal fat distribution is necessary when obese subjects enter a weight reduction programme.
Abdomen↗
Multicomponent phenol hydroxylase-catalysed formation of hydroxyindoles and dyestuffs from indole and its derivatives.
AIMS: To establish multicomponent phenol hydroxylases (mPHs) as novel biocatalysts for producing dyestuffs and hydroxyindoles such as 7-hydroxyindole (7-HI) from indole and its derivatives. METHODS AND RESULTS: We have isolated Pseudomonas sp. KL33, which possesses a phenol degradation pathway similar to that found in Pseudomonas sp. CF600. Pseudomonas sp. KL28 is a strain that can grow on n-alkylphenols as a carbon and energy source. Escherichia coli strains expressing mPH from strain KL28 (mPH(KL28)) and strain KL33 (mPH(KL33)) catalysed the formation of indigo and 7-HI, respectively, from indole. In addition, both mPHs catalysed the production of dyestuffs and hydroxyindoles from indole derivatives. The mPH(KL28) has proved to be one of the most versatile biocatalysts that can accommodate a wide range of indole derivatives for catalysing the formation of dyestuffs. CONCLUSIONS: The present work provides a new approach in producing various dyestuffs and hydroxyindoles from indole and its derivatives by mPHs. SIGNIFICANCE AND IMPACT OF THE STUDY: These results indicate that mPHs may serve as potential agents for organic syntheses as well as bioremediation.
Biotransformation↗
Deep-vein thrombosis rates after major orthopedic surgery in Asia. An epidemiological study based on postoperative screening with centrally adjudicated bilateral venography.
BACKGROUND: The incidence of postsurgical venous thromboembolism is thought to be low in Asian ethnic populations. OBJECTIVE: We studied the incidence of deep-vein thrombosis (DVT) in Asian patients undergoing major orthopedic surgery of the lower limbs. PATIENTS/METHODS: We performed a prospective epidemiological study in 19 centers across Asia (China, Indonesia, South Korea, Malaysia, Philippines, Taiwan, and Thailand) in patients undergoing elective total hip replacement (THR), total knee replacement (TKR) or hip fracture surgery (HFS) without pharmacological thromboprophylaxis. The primary endpoint was the rate of DVT of the lower limbs documented objectively with bilateral ascending venography performed 6-10 days after surgery using a standardized technique and evaluated by a central adjudication committee unaware of local interpretation. RESULTS: Overall, of 837 Asian patients screened for this survey, 407 (48.6%, aged 20-99 years) undergoing THR (n = 175), TKR (n = 136) or HFS (n = 96) were recruited in 19 centers. DVT was diagnosed in 121 of 295 evaluable patients [41.0%, (95% confidence interval (CI): 35.4-46.7)]. Proximal DVT was found in 30 patients [10.2% (7.0-14.2)]. Total DVT and proximal DVT rates were highest in TKR patients (58.1% and 17.1%, respectively), followed by HFS patients (42.0% and 7.2%, respectively), then THR patients (25.6% and 5.8%, respectively). DVT was more frequent in female patients aged at least 65 years. Pulmonary embolism was clinically suspected in 10 of 407 patients (2.5%) and objectively confirmed in two (0.5%). CONCLUSIONS: The rate of venographic thrombosis in the absence of thromboprophylaxis after major joint surgery in Asian patients is similar to that previously reported in patients in Western countries.
Adult↗
Metastatic retinoblastoma of the maxilla and mandible.
Metastatic retinoblastoma of the jaws is very rare. We present a 4-year-old boy with metastatic retinoblastoma that involved both the maxilla and mandible simultaneously. Enhanced CT indicated bone-destructive masses with partially non-enhanced area and enhanced margin in the right maxilla and left mandible. MRI showed well-delineated masses that were isointense on T(1) weighted images and hyperintense on T(2) weighted images. Four weeks after chemotherapy and bone marrow transplantation, the size of lesions remarkably decreased. The patient died 19 months later with extensive tumour metastases despite additional chemotherapy. In this case, the dental crypt of a permanent tooth was considered the potential target through which retinoblastoma metastasized to the jaws.
Child, Preschool↗
Multianalyte profiling of serum cytokines for detection of pancreatic cancer.
Early detection of pancreatic cancer might improve clinical outcome. Significant alterations in the levels of individual serum cytokines have been reported in pancreatic cancer. We hypothesized that a multicytokine panel could serve as biomarkers for pancreatic cancer. To evaluate the diagnostic utility of such a panel, we have utilized a novel multianalyte LabMAP profiling technology that allows simultaneous measurement of multiple markers. In this study, a panel of 31 serological markers including cytokines, chemokines, growth and angiogenic factors in combination with CA 19-9 was analyzed in sera of pancreatic cancer patients, patients with chronic pancreatitis, and matched control healthy subjects. Statistical analysis identified a multicytokine panel that was able to distinguish pancreatic cancer from healthy controls with a sensitivity of 85.7% and specificity of 92.3%, which was superior to performance of CA 19-9 alone. Importantly, a multicytokine panel allowed the discrimination of pancreatic cancer from chronic pancreatitis with high sensitivity of 98% and specificity of 96.4%. In conclusion, we demonstrated that analysis of multiple serum cytokines using a novel LabMAP technology is a promising approach for development of a diagnostic assay for pancreatic cancer.
Biomarkers, Tumor↗