Changes in mesenteric fat thickness and its clinical impact in bariatric surgery

Obesity, especially central obesity is associated with increased risk of metabolic syndrome, non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus. The study aimed to investigate the associations of the changes of abdominal fat thicknesses with changes of anthropometric indexes and improvements of metabolic phenotypes in patients with obesity and T2DM before and after bariatric surgery. Between April 2016 and January 2017, 34 adult patients with concurrent obesity and T2DM scheduled for different bariatric surgeries were prospectively evaluated by ultrasound before and 1-year after bariatric surgery to determine abdominal fat thicknesses (mesenteric fat, preperitoneal fat and subcutaneous fat) and NAFLD. At 1 year, of the 25 patients that finished the study, significant decrease in mesenteric-fat-thickness was associated with significant reduction of obesity, that is, BMI (-24%, p < .001), remission of metabolic syndrome (32%, p = .008), NAFLD (60%, p < .001) and T2DM (44%, p < .001). Lower baseline mesenteric fat thickness was associated with remission of metabolic syndrome. Lower baseline mesenteric-fat-thickness may have the potential to predict metabolic syndrome remission after bariatric surgery.

Relationships between intravoxel incoherent motion parameters and expressions of programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1) in patients with cervical cancer

AIM

To determine the associations of intravoxel incoherent motion (IVIM) parameters with expression of programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1), and evaluate the performance of the combined model established based on IVIM and clinicopathological parameters in predicting PD-L1and PD-1 status of cervical cancer (CC) patients.

MATERIALS AND METHODS

Seventy-eight consecutive CC patients were enrolled prospectively and underwent magnetic resonance imaging (MRI) including IVIM. IVIM quantitative parameters were measured, compared, and correlated with PD-L1 and PD-1 expression. Independent factors related to PD-L1 and PD-1 positivity were identified and were used to establish the combined model. The combined model's diagnostic performance was evaluated using the receiver operating characteristic (ROC) analysis. The Shapley additive explanation (SHAP) algorithm was used to explain the contribution of each parameter in the combined model.

RESULTS

The real diffusion coefficient (D) value was significantly lower in the PD-L1-positive group than in the PD-L1-negative group (0.64 ± 0.12 versus 0.72 ± 0.11, p=0.021). The PD-1-positive and PD-1-negative groups showed similar trends (0.63 ± 0.13 versus 0.73 ± 0.09, p=0.003). Parametrial invasion, lymph node status, pathological grade, FIGO (International Federation of Gynecology and Obstetrics) staging, and D values were independently associated with PD-L1 and PD-1expression. A combined model incorporating these parameters showed good discrimination with the sensitivity, specificity of 90.9%, 82.6% for PD-L1, and 93.5%, 72% for PD-1. According to the SHAP value, FIGO staging and pathological grade were the most influential features of the prediction model.

CONCLUSION

IVIM parameters were found to correlate with PD-L1 and PD-1 expression. The combined model, incorporating parametrial invasion, lymph node status, pathological grade, FIGO staging, and D values, showed good discrimination in predicting PD-L1 and PD-1 status, providing the basis for CC immunotherapy.

Sonographic Measurement of Mesenteric Fat Thickness Is a Better Predictor of Aortic Stiffness Compared With Conventional Obesity Indexes

Increased aortic stiffness is closely associated with central obesity whereas mesenteric fat is the key adipose tissue in central obesity. We investigated the associations of mesenteric fat thickness with aortic stiffness, with comparison to conventional obesity measures. We used ultrasound to measure mesenteric, pre-peritoneal and subcutaneous fat thickness, carotid intima-media thickness (CIMT) and carotid-femoral pulse wave velocity (c-f PWV), an index of central aortic stiffness. Anthropometric indexes, blood pressure, fasting plasma glucose and lipid profile were measured. One hundred forty-seven healthy volunteers (age [mean ± standard deviation]: 43.2 ± 13.3 y; 41.5% men) were assessed. On univariate analysis, mesenteric, preperitoneal and subcutaneous fat thickness, body mass index (BMI), waist circumference (WC), waist/hip ratio (WHR) and waist/height ratio (WHtR) were associated with c-f PWV with or without adjustment for age. The mesenteric fat thickness had the highest correlation coefficient (r = 0.48, p < 0.001) with c-f PWV among all the investigated obesity indexes. Using multiple linear regression analysis, only mesenteric fat thickness remained to be an independent determinant of c-f PWV after adjustments for other abdominal fat thickness, anthropometric and metabolic indexes and CIMT. In conclusion, mesenteric fat thickness is an independent risk factor for aortic stiffness and has a stronger association with aortic stiffness compared with conventional obesity indexes.

Associations of Renal Augmented Velocity Index with Arterial Stiffness, Carotid Intima-Media Thickness and Blood Pressure, in Comparison with Renal Resistive Index

The augmented velocity index (Avi) is a new Doppler index associated with arterial stiffness. We examined associations of renal Avi with blood pressure (BP), aortic stiffness and carotid intima-media thickness (IMT), and compared its performance with that of resistive index (RI). One hundred forty-seven volunteers were recruited. Renal Avi had significant positive correlations with systolic BP (r = 0.37, p < 0.001), diastolic BP (r = 0.2, p = 0.016), mean arterial pressure (r = 0.29, p < 0.001), pulse pressure (r = 0.31, p < 0.001), carotid-femoral pulse wave velocity (r = 0.49, p < 0.001) and carotid IMT (r = 0.23, p = 0.005). RI correlated positively with pulse pressure (r = 0.3, p < 0.001) only. After adjustments for co-variables, the associations remained similar. Patients with abnormal BP values (≥130/80 mm Hg), IMT and aortic stiffness (≥1 standard deviation of mean value) had higher Avi than those with normal values, but not RI. In conclusion, renal Avi had stronger associations with BP, arterial stiffness and carotid IMT than RI in apparently healthy volunteers, and was significantly increased in abnormal patients.

Intermediate phenotypes of childhood obstructive sleep apnea

An intermediate phenotype of a disease is a trait in the path of pathogenesis from genetic predisposition to disease manifestation. Identifying intermediate phenotypes with high heritability is helpful in delineating the genetics of a disorder. In this study, we aimed to examine various traits with regards to obesity, cardiovascular risk and upper airway structure to identify potential intermediate phenotypes of childhood obstructive sleep apnea (OSA). Children aged between 6 and 18 years and their parents and siblings were recruited. All subjects underwent anthropometric measurements, cardiovascular risk assessment, sonographic measurement of lateral parapharyngeal wall (LPW) thickness, X-ray cephalometry and overnight polysomnography. A total of 34 phenotypes were examined. One hundred and one families consisting of 127 children (46 overweight) and 198 adults (84 overweight) were recruited. Heritability of obstructive apnea-hypopnea index (OAHI) was significant in overweight (h²  = 0.54) but not normal-weight individuals (h²  = 0.12). LPW thickness (h²  = 0.68) and resting blood pressure (h²  = 0.36 and 0.43 for systolic blood pressure [SBP] and diastolic blood pressure [DBP], respectively) were significantly heritable and associated with OAHI. Moreover, these traits were found to have shared genetic variance with OAHI in the overweight subgroup. Hyoid bone position also had significant heritability (h²  = 0.55) and association with OAHI but genetic correlation with OSA severity was not demonstrated. These findings suggest that LPW thickness and resting blood pressure are possible intermediate phenotypes of OSA independent of body mass index, especially in overweight patients. Identifying genes relevant to these phenotypes may help to elucidate the genetic susceptibility of OSA.

Augmented Velocity Index: A New Doppler Index Associated with Arterial Stiffness

Augmented Velocity Index (Avi) is a new Doppler index developed to quantify velocity changes at the late systolic peak. We examined its reliability, association with arterial stiffness and cardiovascular risk factors. The Avi is calculated as (late systolic peak velocity - early systolic peak velocity)/(highest peak systolic velocity - end-diastolic velocity). Fifty volunteers (mean age ± standard deviation: 43.5 ± 14.2 y, men: 52%) without known medical illnesses or drug use were recruited. Carotid Doppler waveforms with measurements of Avi were recorded. Carotid pressure waveforms were obtained by applanation tonometry for measurement of the Augmentation Index (AI). Clinical measurements including body mass index (BMI) and blood pressure (BP) were assessed, and fasting blood was taken for measurement of glycemia and lipid profile. Another 15 volunteers (age range: 22-60 y, men: 33.3%) were recruited to study the reliability of Avi measurement. The results revealed that carotid Avi closely correlated with the index of arterial stiffness, AI (r = 0.76, p < 0.001) on Pearson correlation. On multiple linear regression analysis, Avi remained a significant independent determinant of AI after adjustments for clinical variables. The Avi had significant associations with cardiovascular risk factors (age, BMI, total cholesterol, low-density lipoprotein cholesterol, systolic and diastolic BP). The intra-class correlation coefficients for inter-observer and intra-observer reliability of Avi measurements were 0.93 (95% confidence interval [CI]: 0.8-0.98) and 0.97 (95% CI: 0.92-0.99) respectively. In conclusion, the Avi is a reproducible new Doppler index, independently associated with arterial stiffness in terms of the AI, which initially correlated with cardiovascular risk factors.

Potential Anatomic Markers of Obstructive Sleep Apnea in Prepubertal Children

STUDY OBJECTIVES

Adenotonsillar hypertrophy is the major cause of obstructive sleep apnea (OSA) in prepubertal children, but children without enlarged lymphoid tissues may still suffer from OSA. This study aimed to identify other potential anatomic features associated with childhood OSA.

METHODS

This prospective study took place between January 2010 and April 2014. Prepubertal children suspected to have OSA, aged 6 to 11 years, were recruited. They underwent anthropometric measurements, nocturnal polysomnography, tonsil size evaluation, x-ray cephalometry, and sonographic measurement of lateral parapharyngeal wall (LPW) thickness. Linear regression analyses were used to test for the association between anatomic measurements and OSA severity. Logistic regression analyses were used to identify potential anatomic markers for different cutoffs (obstructive apneahypopnea index (OAHI) ≥ 1 and ≥ 5 events/h) for OSA.

RESULTS

Forty-seven children with OSA (20 with moderate to severe disease) and 43 children for the control group were recruited. Sonographic measurement of LPW thickness and position of hyoid bone taken from x-ray cephalometry were risk factors associated with OSA. Linear regression analyses found that these two phenotypes were associated with OAHI. Multivariate models adjusted for age, sex, body mass index, z score, and tonsil size revealed that lower position of hyoid bone was independently associated with higher risk for OSA, whereas both lower position of hyoid bone and greater LPW thickness were associated with higher OAHI and also a higher risk for moderate to severe OSA.

CONCLUSIONS

Position of hyoid bone and LPW thickness are anatomical markers of childhood OSA independent of obesity and tonsil size. Screening tools may include cephalometry and sonographic measurement of LPW to allow better delineation of OSA risk.

Occurrence, Distribution, and Molecular Characterization of Citrus yellow vein clearing virus in China

In 2009, a new citrus viral disease caused by Citrus yellow vein clearing virus (CYVCV) was discovered in China. To more effectively monitor the presence of CYVCV, a survey was conducted in 166 citrus orchards from 11 major citrus-growing provinces in China from May 2014 to April 2016. In all, 458 of a total of 2,350 citrus samples tested positive for CYVCV, demonstrating that the virus is widely distributed in China. In this study, the complete genome sequences of 19 CYVCV isolates from different provinces and hosts were sequenced and characterized. Comparisons of the whole-genome sequences of these 19 CYVCV isolates as well as 4 isolates previously reported from around the world revealed that the sequence identity ranged from 97.1 to 99.8%, indicating that there is a very low level of sequence heterogeneity among CYVCV isolates of different geographic origins and hosts. Phylogenetic analysis of these 23 genomic sequences suggested that all of the isolates from China were clustered into the same clade, clearly apart from the CYVCV isolates from Turkey and Pakistan. To our knowledge, this is the first extensive survey conducted in China for CYVCV incidence.

Association of MyoD1a and MyoD1b gene polymorphisms and meat quality traits in rainbow trout

In this study, we identified myogenic regulatory factors (MRFs) and analyzed the correlation between MRFs and meat quality in rainbow trout. The MyoD1a and MyoD1b genes were cloned from rainbow trout using a homology cloning method. Introns 1 and 2 in the MyoD1a and MyoD1b genes were cloned and submitted to GenBank (accession Nos. FJ623462 and FJ793566). Polymorphisms of MyoD1a and MyoD1b genes were analyzed using single-strand conformation polymorphism and sequencing, respectively. Two single nucleotide polymorphisms were detected in the MyoD1 gene, located at 129G→A in exon 1 and 37 G→A in exon 2. The 37 G→A mutation in exon 2 induced the R185K amino acid change in the polypeptide chain. Seven single nucleotide polymorphisms in the MyoD2 gene were detected, including 218T→C, 224T→C, 242A→C, 246T→A, 248T→C, 305T→C, and 329C→T. The 246T→A mutation in exon 1 induced the R83K change in the polypeptide chain. In the S3 fragment, meat quality traits of genotypes AA and AB significantly differed from those of genotype BB (P < 0.05). In the S5 fragment, meat quality traits of the genotypes AA and AC were significantly different from the genotypes BB and BC (P < 0.05). These results indicate that the MyoD1a and MyoD1b genes have an important influence on meat quality or were linked to the major genes in these strains. These genes can be used to control muscle fiber traits in rainbow trout, and the mutations in the S3 and S5 fragments can be used as molecular markers for selecting rainbow trout with better meat quality traits.

Shear Wave Elastography--A New Quantitative Assessment of Post-Irradiation Neck Fibrosis

PURPOSE

Shear wave elastography (SWE) is a new technique which provides quantitative assessment of soft tissue stiffness. The aim of this study was to assess the reliability of SWE stiffness measurements and its usefulness in evaluating post-irradiation neck fibrosis.

MATERIALS AND METHODS

50 subjects (25 patients with previous radiotherapy to the neck and 25 sex and age-matched controls) were recruited for comparison of SWE stiffness measurements (Aixplorer, Supersonic Imagine). 30 subjects (16 healthy individuals and 14 post-irradiated patients) were recruited for a reliability study of SWE stiffness measurements. SWE stiffness measurements of the sternocleidomastoid muscle and the overlying subcutaneous tissues of the neck were made. The cross-sectional area and thickness of the sternocleidomastoid muscle and the overlying subcutaneous tissue thickness of the neck were also measured. The post-irradiation duration of the patients was recorded.

RESULTS

The intraclass correlation coefficients for the intraoperator and interoperator reliability of deep and subcutaneous tissue SWE stiffness ranged from 0.90-0.99 and 0.77-0.94, respectively. The SWE stiffness measurements (mean +/- SD) of deep and subcutaneous tissues were significantly higher in the post-irradiated patients (64.6 ± 46.8 kPa and 63.9 ± 53.1 kPa, respectively) than the sex and age-matched controls (19.9 ± 7.8 kPa and 15.3 ± 8.37 respectively) (p < 0.001). The SWE stiffness increased with increasing post-irradiation therapy duration in the Kruskal Wallis test (p < 0.001) and correlated with muscle atrophy and subcutaneous tissue thinning (p < 0.01).

CONCLUSION

SWE is a reliable technique and may potentially be an objective and specific tool in quantifying deep and subcutaneous tissue stiffness, which in turn reflects the severity of neck fibrosis.

Mesenteric fat thickness is associated with increased risk of obstructive sleep apnoea

BACKGROUND AND OBJECTIVE

Mesenteric fat is a type of intraperitoneal adipose tissue draining into portal circulation. The objective of this study was to investigate the relationships between mesenteric fat thickness and obstructive sleep apnoea (OSA) in patients with suspected OSA.

METHODS

One hundred forty-nine subjects (men: 114; women: 35) with suspected OSA underwent ultrasound examinations of mesenteric, preperitoneal and subcutaneous fat thickness after overnight polysomnography. Body mass index (BMI) and neck circumference were recorded.

RESULTS

The subjects with OSA (n = 130, apnoea/hypopnoea index (AHI) >5/h) had greater neck circumference, higher BMI, and greater mesenteric and preperitoneal fat thickness than those without OSA (n = 19, AHI ≤ 5/h). There was positive correlation of AHI with mesenteric (r = 0.43, P < 0.001) and preperitoneal fat thickness (r = 0.3, P < 0.001), whereas no significant association was observed between AHI and subcutaneous fat thickness (r = 0.09, P = 0.27). On multivariate logistic regression, after adjustments for gender, age, BMI, neck circumference, and preperitoneal and subcutaneous fat thickness, the mesenteric fat thickness had a positive association with the presence of moderate OSA and severe OSA, with odds ratios of 7.18 and 7.45 for every 1 cm increase in mesenteric fat thickness when AHI was defined as ≥15/h and AHI ≥ 30/h, respectively.

CONCLUSIONS

Mesenteric fat thickness is associated with increased risk of OSA, independent of other abdominal fat thickness, BMI and neck circumference. Sonographic measurement is potentially a useful tool for further evaluating the complex association of visceral fat, metabolic syndrome and OSA.

Intrarenal arterial resistance is associated with microvascular complications in Chinese type 2 diabetic patients

BACKGROUND

Increased renal arterial resistance is associated with various types of chronic renal parenchymal diseases. A resistance index (RI) > 0.8 predicts deterioration in renal function in diabetic subjects. However, the association between renal RI and other diabetic complications has not been investigated. In this study, we examined the association between intrarenal arterial RI and diabetic complications in Chinese type 2 diabetic subjects.

METHODS

Three hundred and eighty-seven Chinese type 2 diabetic patients were recruited from a structured assessment programme to evaluate their risk factors and complications as a part of the quality improvement programme at the Prince of Wales Hospital. All subjects underwent ultrasound examinations for the assessment of intrarenal arterial RI of both kidneys. Clinical and biochemical parameters, including diabetes-related microvascular complications (nephropathy, retinopathy and sensory neuropathy) and macrovascular diseases, were examined.

RESULTS

The mean RI of patients with any microvascular complications (0.70 ± 0.09 versus 0.65 ± 0.06) such as nephropathy (0.71 ± 0.09 versus 0.66 ± 0.06), retinopathy (0.71 ± 0.08 versus 0.67 ± 0.08) and sensory neuropathy (0.75 ± 0.07 versus 0.68 ± 0.08) and with any macrovascular complications (0.71 ± 0.09 versus 0.68 ± 0.08) was higher than those without (P < 0.05). On multivariate analysis, after controlling for confounding variables, an RI ≥0.75 was associated with microvascular complications, nephropathy, retinopathy and sensory neuropathy, with odds ratio of 4.02 [95% confidence interval (CI) 1.72-9.4], 4.99 (2.61-9.56), 2.78 (1.52-5.09) and 5.74 (1.8-18.3), respectively. The association of RI with macrovascular complications was not significant in multivariate analysis.

CONCLUSION

Increased intrarenal arterial resistance was independently associated with an increased risk of microvascular complications including diabetic nephropathy, diabetic retinopathy and diabetic sensory neuropathy in Chinese type 2 diabetic patients.

Fourier transform infrared spectroscopy approach for measurements of photoluminescence and electroluminescence in mid-infrared

An improved Fourier transform infrared spectroscopy approach adapting to photoluminescence and electroluminescence measurements in mid-infrared has been developed, in which diode-pumped solid-state excitation lasers were adopted for photoluminescence excitation. In this approach, three different Fourier transform infrared modes of rapid scan, double modulation, and step scan were software switchable without changing the hardware or connections. The advantages and limitations of each mode were analyzed in detail. Using this approach a group of III-V and II-VI samples from near-infrared extending to mid-infrared with photoluminescence intensities in a wider range have been characterized at room temperature to demonstrate the validity and overall performances of the system. The weaker electroluminescence of quantum cascade lasers in mid-infrared band was also surveyed at different resolutions. Results show that for samples with relatively strong photoluminescence or electroluminescence out off the background, rapid scan mode is the most preferable. For weaker photoluminescence or electroluminescence overlapped with background, double modulation is the most effective mode. To get a better signal noise ratio when weaker photoluminescence or electroluminescence signal has been observed in double modulation mode, switching to step scan mode should be an advisable option despite the long data acquiring time and limited resolution.

Sonographic measurement of mesenteric fat predicts presence of fatty liver among subjects with polycystic ovary syndrome

OBJECTIVE

Visceral fat is believed to be important in the pathogenesis of metabolic syndrome and fatty liver. In this study, we examined the relationship between mesenteric fat thickness and other sonographic indices of adiposity and the presence of fatty liver among subjects with polycystic ovary syndrome (PCOS).

SUBJECTS AND METHODS

A total of 117 Chinese subjects with PCOS were evaluated (mean age, 28.6 ± 6.5 yr; mean body mass index, 24.3 ± 5.3 kg/m(2)). Anthropometric measurements and metabolic risk profile, including a standard oral glucose tolerance test, were assessed in all subjects. All subjects underwent an ultrasound examination for measurement of thickness of mesenteric, preperitoneal, and sc fat as well as evaluation for fatty liver.

RESULTS

Forty-six (39.3%) of the subjects had fatty liver. PCOS subjects with fatty liver had higher body mass index, waist circumference, waist-hip ratio, and systolic blood pressure; a more unfavorable lipid profile with higher triglyceride; lower high-density lipoprotein cholesterol; higher fasting glucose and insulin; higher 2-h glucose during oral glucose tolerance test; lower SHBG; and higher alanine aminotransferase. Subjects with fatty liver had increased thickness of preperitoneal, mesenteric, and sc fat, as well as increased carotid intima-media thickness. Abdominal fat thickness showed moderate correlation to alanine aminotransferase as well as fasting insulin. On multivariate logistic regression, fasting insulin and mesenteric fat thickness were identified as independent predictors of fatty liver among subjects with PCOS.

CONCLUSION

Fatty liver is present in a significant proportion of Chinese patients with PCOS. Sonographic measurement of mesenteric fat is an independent determinant of fatty liver among subjects with PCOS and identifies subjects at increased cardiovascular risk.

Potential of pranlukast and zafirlukast in the inhibition of human liver cytochrome P450 enzymes

1. The potential of zafirlukast to inhibit several human cytochrome P450 enzymes is well known. However, pranlukast, a structural analogue of zafirlukast, has not been studied. Accordingly, the inhibitory potential of pranlukast was evaluated and compared with that of zafirlukast, a known CYP2C9 inhibitor, in in vitro microsomal incubation studies. 2. Both pranlukast and zafirlukast showed moderate inhibition of CYP2C9-catalysed tolbutamide 4-methylhydroxylation, competitively inhibiting tolbutamide 4-methylhydroxylation with estimated mean K(i) values of 3.82 +/- 0.50 and 5.86 +/- 0.08 microM, respectively. 3. Pranlukast had no effect on CYP2C19-catalysed S-mephenytoin 4'-hydroxylation or CYP3A4-catalysed midazolam 1-hydroxylation. However, zafirlukast showed minor inhibition of these reactions. Neither pranlukast nor zafirlukast inhibited CYP1A2-catalysed phenacetin O-deethylation, CYP2D6-catalysed dextromethorphan O-demethylation or CYP2E1-catalysed chlorzoxazone 6-hydroxylation. 4. The results suggest that like zafirlukast, pranlukast also has the potential moderately to inhibit CYP2C9-catalysed tolbutamide 4-methylhydroxylation. Therefore, the inhibitory potential of pranlukast should be considered when it is co-administered with CYP2C9 substrates with narrow therapeutic ranges (e.g. S-warfarin, phenytoin).

Stereoselective inhibition of cytochrome P450 forms by lansoprazole and omeprazolein vitro

The stereoselectivity of the inhibitory interaction potential of lansoprazole and omeprazole isomers on six human cytochrome P450 forms was evaluated using human liver microsomes. Lansoprazole enantiomers showed stereoselective inhibition of CYP2C9-catalysed tolbutamide 4-methylhydroxylation, CYP2C19-catalysed S-mephenytoin 4'-hydroxylation, CYP2D6-catalysed dextromethorphan O-demethylation, CYP2E1-catalysed chlorzoxazone 6-hydroxylation and CYP3A4-catalysed midazolam 1-hydroxylation, whereas omeprazole only inhibited CYP2C19 stereoselectively. Of the P450 forms tested, CYP2C19-catalysed S-mephenytoin 4'-hydroxylation was extensively inhibited by both the lansoprazole and omeprazole enantiomers in a competitive and stereoselective manner; the S-enantiomers of both drugs inhibited the hydroxylation more than the R-enantiomers. The estimated K(i) values determined for CYP2C19-catalysed S-mephenytoin 4'-hydroxylation were 0.6, 6.1, 3.4 and 5.7 microM for S-lansoprazole, R-lansoprazole, S-omeprazole and R-omeprazole, respectively. The results indicate that although both lansoprazole and omeprazole are strong inhibitors of CYP2C19, the inhibition of CYP2C19 by lansoprazole is highly stereoselective, whereas the inhibition by omeprazole is less stereoselective. In addition, S-lansoprazole, the most potent CYP2C19 inhibitor, is not a good CYP2C19-selective inhibitor owing to its inhibition of other P450 forms.

Dietary salt does not influence the disposition of verapamil enantiomers in relation to efflux transporter ABCB1 genetic polymorphism in healthy Korean subjects

To evaluate the effects of dietary salt on the stereoselective disposition of verapamil enantiomers in relation to the transporter ABCB1 2677GG/3435CC and 2677TT/3435TT haplotypes, ten healthy subjects were asked to take diets of three different salt levels for 7 days in a randomized, three-way crossover manner. The plasma concentrations of verapamil and norverapamil enantiomers were determined after a single oral dose of 240 mg verapamil on the last day of each phase. Pharmacokinetic parameters were calculated by non-compartmental analysis techniques and compared among the three different dietary salt phases. Compared with the medium salt diet, the high and low salt diets had no significant effect on the disposition of verapamil enantiomers. Moreover, the ABCB1 haplotypes did not alter the impact of dietary salt, although ABCB1 2677TT/3435TT subjects had slightly, but not significantly, higher C(max) and area under the curve (AUC) and lower T(max) for the verapamil enantiomers than did 2677GG/3435CC subjects in each salt phase.

A man with labile blood pressure

Ronald Ma and colleagues discuss the differential diagnosis and management of a patient who presented with recurrent episodes of chest discomfort, palpitations, and labile blood pressure.

Development of the “Inje Cocktail” for High-throughput Evaluation of Five Human Cytochrome P450 Isoforms in vivo

To develop and validate an in vivo cocktail method for high-throughput phenotyping of CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A, 12 healthy subjects received five probe drugs alone or simultaneously. The in vivo phenotyping index of CYP2C9, the ratio of 8 h urine concentration of losartan to its metabolite after a single administration of losartan, was not significantly different from that obtained using the five-drug cocktail. Similarly, the ratios of [omeprazole]/[5-hydroxyomeprazole] (CYP2C19) and [paraxanthine]/[caffeine] (CYP1A2) in 4 h plasma samples and the log ratio of [dextromethorphan]/[dextrorphan] (CYP2D6) in 8 h urine samples and the 4 h plasma concentrations of midazolam (CYP3A) after single administration or well-established three-drug cocktail of caffeine, omeprazole, and dextromethorphan were not significantly different from those after the new five-drug cocktail. In conclusion, the new five-drug cocktail regimen, named the "Inje cocktail," can be used as a tool to phenotype in vivo enzyme activities of CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A with only 4 h blood sampling and 8 h urine collection following simultaneous administration of the five probe drugs.

Mesenteric fat thickness as an independent determinant of fatty liver

OBJECTIVE

Mesenteric fat is drained by the portal circulation and has been suggested to be a key component in obesity-related health risk, notably the metabolic syndrome. There are increasing epidemiological and experimental data showing that fatty liver is another component of this multifaceted syndrome. Given their intimate anatomical and physiological relationships, we hypothesized that mesenteric fat thickness may be independently associated with the risk of fatty liver. To test this hypothesis, we examined the predictive role of various fat deposits including mesenteric fat thickness, and various metabolic variables on the risk of fatty liver.

SUBJECTS AND METHODS

A total of 291 Chinese subjects (134 men and 157 women with a mean BMI of 23.7 kg/m2, range: 16.5-33.4 kg/m2) underwent ultrasound examination for measurement of mesenteric, subcutaneous and preperitoneal fat thickness, and for diagnosis of fatty liver. Body mass index, waist circumference, and waist-hip ratio were recorded. Blood pressure was measured. Fasting plasma glucose, insulin resistance, high-density lipoprotein cholesterol (HDL-C), triglycerides, low-density lipoprotein cholesterol (LDL-C), liver enzymes were determined by common methods.

RESULTS

The subjects with fatty liver had greater abdominal fat thickness and higher anthropometric indexes than those without fatty liver. The subjects with fatty liver also showed higher blood pressure, worse lipid and glycaemic profile compared with those without fatty liver. Using multiple logistic regression analysis, mesenteric fat thickness was a risk factor of fatty liver, independent of body mass index, age, sex, insulin resistance, fasting plasma glucose, lipid and blood pressure. The odds ratio was 1.5 (95% confidence interval: 1.27-1.77) for every 1 mm increase in the mesenteric fat thickness. Measurement of preperitoneal and subcutaneous fat deposits did not show significant associations with fatty liver.

CONCLUSION

Mesenteric fat thickness measured on ultrasound is an independent determinant of fatty liver.

Direct Synthesis of B−C−N Single-Walled Nanotubes by Bias-Assisted Hot Filament Chemical Vapor Deposition

Direct synthesis of large-scale ternary boron carbonitride single-walled nanotubes (BCN-SWNTs) via a bias-assisted HFCVD process was presented. The BCN-SWNTs were grown over the powdery Fe-Mo/MgO catalyst by using CH4, B2H6, and ethylenediamine vapor as the reactant gases. As high as 16 atom % nitrogen can be incorporated within the nanotube shells, with the boron content in the range of 2-4 atom %. The ternary covalent bonding nature of the BCN-SWNTs was well characterized, and the B, C, and N elemental maps were clearly imaged by energy-filtered transmission electron microscopy.

Risk assessment of human exposure to cypermethrin during treatment of mandarin fields

The potential dermal and respiratory exposure assessment and risk assessment for applicator were performed with cypermethrin EC. The pesticide was applied on a mandarin field using a power sprayer. Gloves were used for the hand exposure assessment, mask for face, and dermal patches for the other parts of the body. Personal air monitor equipped with a XAD-2 resin was used for the respiratory exposure assessment. During the application of cypermethrin in the field, the rate of potential dermal exposure ranged from 28.1 to 58.8 mg/h. The major exposure parts were upper-arms (22.1-24.6%) and legs (thigh and shin, 28.3-29.2%) for females and thigh (21.0-46.9%) and hand (14.9-19.3%) for males. Females were exposed more than males. No exposure was detected from the respiratory monitoring. For risk assessment, the potential dermal exposure (PDE), the absorbable quantity of exposure (AQE), and the margin of safety (MOS) were calculated. Among those four risk assessments, MOS was < 1 in only trial I, which indicated any possibility of risk. However, in the others, the possibility of risk was little. Moreover, the safe work time ranged from 3.61 h to 9.69 h.

Mesenteric fat thickness is an independent determinant of metabolic syndrome and identifies subjects with increased carotid intima-media thickness

OBJECTIVE

Mesenteric fat, a reflection of visceral adiposity, may play an important role in the pathogenesis of metabolic syndrome and cardiovascular diseases (CVD). In this study, we examined the independent relationship between mesenteric fat thickness and metabolic syndrome and defined its optimal cutoff value to identify high-risk subjects for metabolic syndrome and CVD.

RESEARCH DESIGN AND METHODS

A total of 290 Chinese subjects had an ultrasound examination for measurements of thickness of mesenteric, preperitoneal, and subcutaneous fat as well as carotid intima-media thickness (IMT). Anthropometric measurements and metabolic risk profile were assessed by physical examination and blood taking.

RESULTS

Twenty (6.9%) subjects had metabolic syndrome according to the National Cholesterol Education Panel Adult Treatment Panel III criteria with Asian definitions for central obesity (waist circumference >80 cm in women and >90 cm in men). Mesenteric fat thickness had significant correlations (P < 0.05) with various metabolic variables. On multivariate regression, mesenteric fat thickness was an independent determinant of all components of metabolic syndrome after adjustment for age, sex, homeostasis model assessment of insulin resistance, and other fat deposits. The odds ratio of metabolic syndrome was increased by 1.35 (95% CI 1.10-1.66)-fold for every 1-mm increase in mesenteric fat thickness. On receiver-operating characteristic curve analysis, mesenteric fat thickness of > or =10 mm was the optimal cutoff value to identify metabolic syndrome, with sensitivity of 70% and specificity of 75%. Subjects with mesenteric fat thickness > or =10 mm had higher carotid IMT than those with thickness <10 mm (0.73 +/- 0.19 vs. 0.64 +/- 0.16 mm, P = 0.001).

CONCLUSIONS

Mesenteric fat thickness was an independent determinant of metabolic syndrome and identified subjects with increased carotid IMT.

Inhibition of human cytochrome P450 isoforms and NADPH-CYP reductase in vitro by 15 herbal medicines, including Epimedii herba

OBJECTIVE

We evaluated the potential of 15 herbal medicines (HMs), commonly used in Korea, to inhibit the catalytic activities of several cytochrome P450 (CYP) isoforms and microsomal NADPH-CYP reductase.

METHODS

The abilities of 1-1000 microg/mL of freeze-dried aqueous extracts of 15 HMs to inhibit phenacetin O-deethylation (CYP1A2), tolbutamide 4-methylhydroxylation (CYP2C9), S-mephenytoin 4'-hydroxylation (CYP2C19), dextromethorphan O-demethylation (CYP2D6), chlorzoxazone 6-hydroxylation (CYP2E1), midazolam 1-hydroxylation (CYP3A4) and NADPH-CYP reductase were tested using human liver microsomes.

RESULTS

The HMs Epimedii herba, Glycyrrhizae radix and Leonuri herba inhibited one or more of the CYP isoforms or NADPH-CYP reductase. Of the three HMs, Epimedii herba extracts were the most potent inhibitors of several CYP isoforms (IC(50) 67.5 microg/mL for CYP2C19, 104.8 microg/mL for CYP2E1, 110.9 microg/mL for CYP2C9, 121.9 microg/mL for CYP3A4, 157.8 microg/mL for CYP2D6 and 168.7 microg/mL for CYP1A2) and NADPH-CYP reductase (IC(50) 185.9 microg/mL ).

CONCLUSION

These results suggest that some of the HMs used in Korea have the potential to inhibit CYP isoforms in vitro. Although the plasma concentrations of the active constituents of the HMs were not determined, some herbs could cause clinically significant interactions because the usual doses of those individual herbs are several grams of freeze-dried extracts. Controlled trials to test the significance of these results are necessary.

The preferred magnetic resonance imaging planes in quantifying visceral adipose tissue and evaluating cardiovascular risk

BACKGROUND

Magnetic Resonance Imaging (MRI) is a well-accepted non-invasive method in the quantification of visceral adipose tissue. However, a standard method of measurement has not yet been universally agreed.

OBJECTIVES

The objectives of the present study were 2-fold, firstly, to identify the imaging plane in the Chinese population which gives the best correlation with total visceral adipose tissue volume and cardiovascular risk factors; and secondly to compare the correlations between single-slice and multiple-slice approach with cardiovascular risk factors.

METHODS

Thirty-seven Chinese subjects with no known medical history underwent MRI examination for quantifying total visceral adipose tissue volume. The visceral adipose tissue area at five axial imaging levels within abdomen and pelvis were determined. All subjects had blood pressure measured and fasting blood taken for analysis of cardiovascular risk factors. Framingham risk score for each subject was calculated.

RESULTS

The imaging plane at the level of 'lower costal margin' (LCM) in both men and women had the highest correlation with total visceral adipose tissue volume (r = 0.97 and 0.99 respectively). The visceral adipose tissue area at specific imaging levels showed higher correlations with various cardiovascular risk factors and Framingham risk score than total visceral adipose tissue volume. The visceral adipose tissue area at 'umbilicus' (UMB) level in men (r = 0.88) and LCM level in women (r = 0.70) showed the best correlation with Framingham risk score.

CONCLUSIONS

The imaging plane at the level of LCM is preferred for reflecting total visceral adipose tissue volume in Chinese subjects. For investigating the association of cardiovascular risk with visceral adipose tissue in MRI-obesity research, the single-slice approach is superior to the multiple-slice approach, with the level of UMB in men and LCM in women as the preferred imaging planes.

Association of carotid intima-media thickness with mesenteric, preperitoneal and subcutaneous fat thickness

Carotid intima-media thickness (IMT) is an established surrogate marker for atherosclerosis. We have previously reported that abdominal fat, notably mesenteric fat, was a major explanatory variable for multiple cardiovascular risk factors. Given the intimate relationships between visceral fat, cardiovascular risk factors and atherosclerosis, we hypothesize that there are independent relationships between mesenteric fat and carotid IMT. Two hundred and eighty-two Chinese subjects (M: 129, F: 153; mean body mass index (BMI): 23.8 kg/m(2); age range: 20-68 years) were recruited. Maximum carotid IMT as well as maximum mesenteric, preperitoneal and subcutaneous fat thickness were measured by carotid and abdominal ultrasound examinations, respectively. Obesity index and conventional cardiovascular risk factors were assessed by physical examination and blood taking. On univariate analysis, mesenteric but not preperitoneal fat thickness was the major correlate with carotid IMT in both men and women. There was also a weak correlation between carotid IMT and subcutaneous fat thickness in women. On multivariate analysis, mesenteric fat thickness was an independent determinant of carotid IMT after adjustment for subcutaneous and preperitoneal fat thickness, age, gender, blood pressure, insulin resistance, lipid and glycaemic parameters. The association of mesenteric fat thickness with carotid IMT appeared stronger in women than in men, which however was not confirmed on multivariate analysis. In conclusion, mesenteric fat thickness measured on ultrasound showed significant association with carotid IMT, lending further support to the linking role of portal adipose tissue in obesity-related atherosclerosis. Effect of gender on the relationships of mesenteric fat with atherosclerosis risk require further elucidation. Measurement of mesenteric fat thickness may be a useful indicator of regional fat distribution in the assessment of cardiovascular risks.

Sonographic measurement of mesenteric fat thickness is a good correlate with cardiovascular risk factors: comparison with subcutaneous and preperitoneal fat thickness, magnetic resonance imaging and anthropometric indexes

OBJECTIVE

Visceral fat, notably mesenteric fat, which is drained by the portal circulation, plays a critical role in the pathogenesis of metabolic syndrome through increased production of free fatty acids, cytokines and vasoactive peptides. We hypothesize that mesenteric fat thickness as measured by ultrasound scan could explain most of the obesity-related health risk. We explored the relationships between cardiovascular risk factors and abdominal fat as determined by sonographic measurements of thickness of mesenteric, preperitoneal and subcutaneous fat deposits, total abdominal and visceral fat measurement by magnetic resonance imaging (MRI) and anthropometric indexes.

DESIGN

A cross-sectional study.

SUBJECTS

Subjects included 18 healthy men and 19 women (age: 27-61 y, BMI: 19-33.4 kg/m(2)).

MEASUREMENTS

The maximum thickness of mesenteric, preperitoneal and subcutaneous fat was measured by abdominal ultrasound examination. MRI examinations of whole abdomen and pelvis were performed and the amount of total abdominal and visceral fat was quantified. The body mass index, waist circumference and waist-hip ratio were recorded. Cardiovascular risk factors were assessed by physical examination and blood taking.

RESULTS

Men had more adverse cardiovascular risk profile, higher visceral fat volume and thicker mesenteric fat deposits than women. Among all the investigated obesity indexes, the mesenteric fat thickness showed the highest correlations with total cholesterol, LDL-C, triglycerides, fasting plasma glucose, HbA(1c) and systolic blood pressure in men, and with triglycerides and HbA(1c) in women. On stepwise multiple regression analysis with different obesity indexes as independent variables, 30-65% of the variances of triglycerides, total cholesterol, LDL-C and HbA(1c) in men, and triglycerides in women were explained by the mesenteric fat thickness.

CONCLUSION

Compared with sonographic measurement of subcutaneous and preperitoneal fat thickness, MRI measurement of total abdominal and visceral fat and anthropometric indexes, sonographic measurement of mesenteric fat thickness showed better associations with some of the cardiovascular risk factors. It may potentially be a useful tool to evaluate regional distribution of obesity in the assessment of cardiovascular risk.

Cicerarin, a novel antifungal peptide from the green chickpea

A peptide designated cicerarin, with an N-terminal amino acid sequence VKSTGRADDDLAVKTKYLPP dissimilar from known proteins and peptides and a molecular mass of 8kDa, was isolated from seeds of the green chickpea Cicer arietinum cv green chickpea. Cicerarin was isolated with a procedure that involved ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, and gel filtration by fast protein liquid chromatography on Superdex 75. Cicerarin was unadsorbed on DEAE-cellulose and adsorbed on Affi-gel blue gel in 10mM Tris-HCl buffer (pH 7.3). Cicerarin exerted antifungal activity against Botrytis cinerea, Mycosphaerella arachidicola, and Physalospora piricola. The antifungal activity was preserved after exposure to 100 degrees C for 15min.

Sonographic characterisation of radiation-induced carotid artery stenosis

BACKGROUND AND PURPOSE

To study the distribution, extent and sonographic characterisation of radiation-induced carotid artery stenosis in nasopharyngeal carcinoma (NPC) patients.

METHODS

The distribution of plaques, the extent of stenosis, and the sonographic characterisation of the plaque at maximum stenosis were recorded in 71 NPC patients. The results were compared with the ultrasound results of a control group of 142 patients presenting with symptoms of cerebrovascular disease or carotid bruit.

RESULTS

NPC patients had a higher incidence of carotid stenosis (77 vs. 50.7%). The common carotid arteries were most commonly affected by radiation-induced stenosis (93/142 vs. 37/284 in the control group), whereas the carotid bulb was the most commonly affected (56/284) site in the control group. Significantly more NPC patients had moderate-to-severe stenosis (21/71 vs. 27/142). Analysis of the sonographic appearance of radiation-induced and atherosclerotic plaques showed more diffuse involvement in the post-radiation group. Non-calcified plaques and intraplaque hypoechoic foci were also more frequent in the post-radiation group.

CONCLUSIONS

Radiation-induced carotid stenosis is more diffuse in distribution, is associated with more severe luminal stenosis and has different sonographic plaque characterisation compared with carotid stenosis without radiation exposure.

Carotid intima-media thickness in patients with head and neck irradiation for the treatment of nasopharyngeal carcinoma

AIM

Intima-media thickness (IMT) has been shown to be useful in the evaluation and monitoring of carotid artery atherosclerosis in patients at risk of cardiovascular events. In this study, we aimed to examine the IMT in patients with nasopharyngeal carcinoma (NPC) who received irradiation to the carotid arteries during radiotherapy, and compared them with a control group.

MATERIALS AND METHODS

Fifty-one NPC patients (aged between 39 and 69 years) and a group of 51 age-and sex-matched controls were studied by ultrasound. The IMT at the far wall of the common carotid artery was measured three times and the average value taken in each subject. The IMT of both groups were compared. Risk factors for IMT thickness, including hypertension, smoking, hyperglycaemia, hypercholesterolaemia, history of cerebrovascular accidents and cardiovascular disease, were also studied.

RESULTS

The mean carotid IMT of patients in the NPC group (2.2+/-1.5 mm) was statistically greater than that in normal controls (0.7+/-0.15 mm) (P < 0.05). There was no statistically significant difference between the IMT in the right and left common carotid arteries within each group of patients.

CONCLUSION

The findings suggest that patients with irradiation have increased arterial IMT. As they are asymptomatic the clinical relevance is not clear.

In vivo pharmacokinetics of pyribenzoxim in rats

Pyribenzoxim, benzophenone O-[2,6-bis(4,6-dimethoxypyrimidin-2-yloxy)benzoyl]oxime, is a new post-emergence herbicide providing broad-spectrum weed control in rice fields. [14C]Pyribenzoxim was used to study the pharmacokinetics of the compound after oral administration of a dose of 1000 mg kg-1 to male Sprague-Dawley rats. The material balance ranged from 97.3 to 99.7% of the administered dose and urinary and fecal recovery accounted for 97.1%, with the majority of radioactivity recovered in feces (88.6%) by 168 h after treatment. Elimination as volatile products or as carbon dioxide was negligible. The following values were obtained for the compound in the blood: AUC0-168 h, 28,400 micrograms equiv hg-1; Tmax, 12 h; Cmax, 372 micrograms equiv g-1; half-life, 53 h. Radioactivity in tissue decreased from 96.1% of applied radiocarbon at 6 h to 0.4% at 168 h and the highest concentration of radioactivity among the tissues was observed in liver while the lowest residues were found in brain. The elimination half-lives of radioactivity from tissues was in the range of 7 to 77 h and Tmax values of 12, 24 and 12 h were observed for blood, liver and kidney, respectively. Except for that in the digestive tract, the tissue-to-blood ratio (TBR) was highest in the liver.

Incidence of deep vein thrombosis after colorectal surgery in a Chinese population

INTRODUCTION

Contemporary studies indicate that the incidence of deep vein thrombosis (DVT) is increasing in the Asian population. The present study aims to evaluate the incidence of postoperative DVT in Chinese patients undergoing surgery for colorectal malignancies.

METHODS

Fifty-one consecutive patients with carcinoma of the rectum or sigmoid colon scheduled for resection were included in the study. None of the study subjects were given any form of DVT prophylaxis. Serial duplex ultrasound of both lower limbs were examined in the preoperative and postoperative periods.

RESULTS

Three patients were excluded from the study because of the presence of DVT noted preoperatively. A total of 20/48 (41.7%) patients developed asymptomatic calf vein thrombosis. One out of 20 patients required anticoagulation because of thrombus propagation. None of the subjects showed signs or symptoms of DVT or pulmonary embolism. A total of 7/20 thrombi resolved completely at 4 weeks after operation. Only old age and smoking were identified as being associated with a higher incidence of DVT. Disseminated disease, type of operation, duration of operation and postoperative complications did not appear to be risk factors for DVT.

CONCLUSION

A high incidence of asymptomatic calf vein thrombosis occurred after colorectal surgery for malignancies in Chinese. The majority did not progress even without anticoagulation.

Incidence of carotid stenosis in nasopharyngeal carcinoma patients after radiotherapy

BACKGROUND

Radiation-induced carotid stenosis in patients with head and neck tumors can cause significant mortality and morbidity. This study examined the incidence of stenosis in the extracranial carotid arteries of nasopharyngeal carcinoma patients after radiotherapy.

METHODS

The extracranial carotid arteries of 71 (53 male and 18 female; mean age of 53.6 years) postradiation patients with nasopharyngeal carcinoma were examined with color Doppler ultrasound. The distribution of the arterial stenosis and the degree of stenosis were documented. The results were compared with the control group, which comprised 51 newly diagnosed nasopharyngeal carcinoma patients (35 male and 16 female, mean age of 48.8 years) before radiotherapy. Incidences of risk factors for arterial stenosis such as hypertension, smoking, and hypercholesterolemia also were studied in these two groups.

RESULTS

There was no significant difference in the incidence of risk factors between the two groups. Arterial stenosis was, however, more common in the postradiation group than the preradiation group (56 of 71 vs. 11 of 51). The common/internal carotid arteries (CCA/ICA) were most commonly involved (55 of 71 vs. 11 of 51; P < 0.01), followed by the external carotid artery (ECA) (32 of 71 vs. 1 of 51; P < 0.01) and vertebral artery (VA; 5 of 71 vs. 0; P = 0.069). Significant stenosis (> 50% reduction of luminal diameter) was only found in the postradiation group (21 of 71 in CCA/ICA, 11 of 71 in ECA, 4 of 71 in VA).

CONCLUSIONS

This study showed that radiation could cause significant carotid stenosis. Ultrasound examinations for these patients therefore are necessary for early detection and possible intervention of this late radiation-induced complication.

A training workshop on late-stage dementia care for family caregivers

Training workshops have been considered a useful intervention in helping family caregivers of people with dementia to cope with the stress of caregiving. However, there are no reports in the literature with regard to training and support of families specifically looking after individuals who are in the late stage of dementia. This paper reports the experience and evaluation of a training workshop aimed at preparing family caregivers for late-stage dementia care. Eighty-eight percent of the participants completed the client satisfaction questionnaire. The results from the questionnaire gave a very positive response, showing 90.9 percent of respondents were satisfied with the workshop, and 77.3 percent of respondents indicated that their caregiving needs were met. Eleven participants who attended this workshop joined a focus group feedback session. The Kruskal-Wallis test found no significant differences between the overall profile of the participants and that of the focus group in terms of age, gender, educational background, whether they were primary caregivers, for whom they cared (e.g., parents or spouse), or whether the care recipient stayed at home or in a nursing home. Findings from the focus group session provide a somewhat different picture from that of the questionnaire. Three focus group participants provided more critical comments of the workshop. Although the majority of the focus group agreed that the workshop had been useful, they disagreed on whether it is necessary to discuss psychosocial issues in this workshop. Findings from the focus group have enabled the project team to reflect on their design and operation of the workshop and provided valuable insight for future development as well as for further study.

Clinically underdetected asymptomatic and symptomatic carotid stenosis as a late complication of radiotherapy in Chinese nasopharyngeal carcinoma patients

BACKGROUND

Carotid artery stenosis is a late complication of radiotherapy to the neck region. This complication has, however, a significant impact with increased risk of stroke causing mortality and morbidity. Clinicians' awareness of this complication and early detection is therefore important.

METHODS

Eighty patients with nasopharyngeal carcinoma (NPC) who had received radiotherapy were recruited for color Doppler ultrasonography of the carotid arteries. fifty-eight patients with newly diagnosed NPC who had never received any radiotherapy were recruited as controls. All patients with significant carotid stenosis were referred to the neurology clinic for further assessment.

RESULTS

Twenty-four patients were found to have more than 50% diameter reduction in the extracranial carotid artery. Clinical assessment by a neurologist showed 9 of 24 patients had a history of transient ischemic attack, amaurosis fugax, or stroke. Seven of these patients had clinically detectable neck bruit.

CONCLUSIONS

Clinicians attending to patients after radiotherapy for head and neck cancers should be aware of this long-term complication of radiotherapy. A detailed clinical history and incorporation of auscultation of carotid arteries in routine follow-up of postradiotherapy patients are recommended.

Northridge earthquake damage caused by geologic focusing of seismic waves

Despite being located 21 kilometers from the epicenter of the 1994 Northridge earthquake (magnitude 6.7), the city of Santa Monica experienced anomalously concentrated damage with Mercalli intensity IX, an intensity as large as that experienced in the vicinity of the epicenter. Seismic records from aftershocks suggest that the damage resulted from the focusing of seismic waves by several underground acoustic lenses at depths of about 3 kilometers, formed by the faults that bound the northwestern edge of the Los Angeles basin. The amplification was greatest for high-frequency waves and was less powerful at lower frequencies, which is consistent with focusing theory and finite-difference simulations.

Cloning and functional characterization of an Arabidopsis nitrate transporter gene that encodes a constitutive component of low-affinity uptake

The Arabidopsis CHL1 (AtNRT1) gene encodes an inducible component of low-affinity nitrate uptake, which necessitates a "two-component" model to account for the constitutive low-affinity uptake observed in physiological studies. Here, we report the cloning and characterization of a CHL1 homolog, AtNRT1:2 (originally named NTL1), with data to indicate that this gene encodes a constitutive component of low-affinity nitrate uptake. Transgenic plants expressing antisense AtNRT1:2 exhibited reduced nitrate-induced membrane depolarization and nitrate uptake activities in assays with 10 mM nitrate. Furthermore, transgenic plants expressing antisense AtNRT1:2 in the chl1-5 background exhibited an enhanced resistance to chlorate (7 mM as opposed to 2 mM for the chl1-5 mutant). Kinetic analysis of AtNRT1:2-injected Xenopus oocytes yielded a K(m) for nitrate of approximately 5.9 mM. In contrast to CHL1, AtNRT1:2 was constitutively expressed before and after nitrate exposure (it was repressed transiently only when the level of CHL1 mRNA started to increase significantly), and its mRNA was found primarily in root hairs and the epidermis in both young (root tips) and mature regions of roots. We conclude that low-affinity systems of nitrate uptake, like high-affinity systems, are composed of inducible and constitutive components and that with their distinct functions, they are part of an elaborate nitrate uptake network in Arabidopsis.

CHL1 is a dual-affinity nitrate transporter of Arabidopsis involved in multiple phases of nitrate uptake

Higher plants have both high- and low-affinity nitrate uptake systems. These systems are generally thought to be genetically distinct. Here, we demonstrate that a well-known low-affinity nitrate uptake mutant of Arabidopsis, chl1, is also defective in high-affinity nitrate uptake. Two to 3 hr after nitrate induction, uptake activities of various chl1 mutants at 250 microM nitrate (a high-affinity concentration) were only 18 to 30% of those of wild-type plants. In these mutants, both the inducible phase and the constitutive phase of high-affinity nitrate uptake activities were reduced, with the inducible phase being severely reduced. Expressing a CHL1 cDNA driven by the cauliflower mosaic virus 35S promoter in a transgenic chl1 plant effectively recovered the defect in high-affinity uptake for the constitutive phase but not for the induced phase, which is consistent with the constitutive level of CHL1 expression in the transgenic plant. Kinetic analysis of nitrate uptake by CHL1-injected Xenopus oocytes displayed a biphasic pattern with a Michaelis-Menten Km value of approximately 50 microM for the high-affinity phase and approximately 4 mM for the low-affinity phase. These results indicate that in addition to being a low-affinity nitrate transporter, as previously recognized, CHL1 is also involved in both the inducible and constitutive phases of high-affinity nitrate uptake in Arabidopsis.

CHL1 is a dual-affinity nitrate transporter of Arabidopsis involved in multiple phases of nitrate uptake

Higher plants have both high- and low-affinity nitrate uptake systems. These systems are generally thought to be genetically distinct. Here, we demonstrate that a well-known low-affinity nitrate uptake mutant of Arabidopsis, chl1, is also defective in high-affinity nitrate uptake. Two to 3 hr after nitrate induction, uptake activities of various chl1 mutants at 250 microM nitrate (a high-affinity concentration) were only 18 to 30% of those of wild-type plants. In these mutants, both the inducible phase and the constitutive phase of high-affinity nitrate uptake activities were reduced, with the inducible phase being severely reduced. Expressing a CHL1 cDNA driven by the cauliflower mosaic virus 35S promoter in a transgenic chl1 plant effectively recovered the defect in high-affinity uptake for the constitutive phase but not for the induced phase, which is consistent with the constitutive level of CHL1 expression in the transgenic plant. Kinetic analysis of nitrate uptake by CHL1-injected Xenopus oocytes displayed a biphasic pattern with a Michaelis-Menten Km value of approximately 50 microM for the high-affinity phase and approximately 4 mM for the low-affinity phase. These results indicate that in addition to being a low-affinity nitrate transporter, as previously recognized, CHL1 is also involved in both the inducible and constitutive phases of high-affinity nitrate uptake in Arabidopsis.

Bovine endometrial retinol-binding protein secretion, messenger ribonucleic acid expression, and cellular localization during the estrous cycle and early pregnancy

Retinol-binding protein (RBP) mRNA was localized to luminal and glandular epithelial cells of bovine endometrium by in situ hybridization. Relative levels of endometrial RBP mRNA expression during the estrous cycle and early pregnancy were determined by quantitative slot blot analysis and contrasted with uterine luminal concentrations of RBP. Expression of mRNA was moderate at Day 1 after estrus, declined at Day 5, reached lowest levels by Day 10, rose significantly through Days 15-17, and peaked at Day 20. RBP mRNA expression in pregnant animals was similar to that in cyclic animals on Day 15, doubled between Days 17 and 20, remained constant through Day 22, and rose slightly thereafter. Luminal RBP concentrations of cyclic cows, as determined by ELISA, decreased from Day 1 through Day 10, rose dramatically on Day 15, then declined through Day 20. Concentrations of RBP in uterine flushes from pregnant animals were similar to those of cyclic cows on Day 15 but remained relatively constant through Day 17. It is concluded that 1) RBP synthesis occurs in the luminal and glandular epithelial cells, 2) RBP transcription and secretion are correlated with each other, and 3) ovarian steroids, possibly in conjunction with uterine concentrations of their receptors, modulate uterine RBP expression.

Use of the ProSpecT microplate enzyme immunoassay for the detection of pathogenic and non-pathogenic Entamoeba histolytica in faecal specimens

A commercial microplate enzyme immunoassay (ProSpecT EIA; Alexon Inc., Sunnyvale, CA 94089, USA) was compared with conventional microscopy for the diagnosis of Entamoeba histolytica infection. Using specimens known to be infected, the sensitivity of the ProSpecT EIA was 78% and its specificity was 99%. No cross reaction with other intestinal parasites was observed. The ProSpecT EIA and conventional microscopy (using merthiolate-iodine-formaldehyde direct wet mounts and concentration techniques) were then used to detect E. histolytica infections in 431 patients in a mental hospital in Taiwan. Using single stool specimens, microscopy detected infection in 10.9% of the patients, compared with 16.9% detected by ProSpecT EIA. The latter method was simple and quick, but more expensive, and could be used to complement microscopy if a prompt diagnosis is desired clinically. However, ProSpecT EIA cannot differentiate between pathogenic E. histolytica and non-pathogenic strains (= E. dispar), which limits its usefulness.

HLA-encoded susceptibility to insulin-dependent diabetes mellitus is determined by DR and DQ genes as well as their linkage disequilibria in a Chinese population

HLA-DRB1 and -DQB1 genes were analyzed in 98 Chinese IDDM patients and 205 control subjects from Taiwan. The DRB1*0301-DQB1*0201 haplotype conferred strong susceptibility (RR = 7.7, pc < 10(-5)). DRB1*0405 also conferred susceptibility (RR = 3.1, Pc < 0.0005) whereas DRB1*0403 (RR = 0.7) and DRB1*0406 (RR = 0.2) conferred protection. Indeed, the relative risk for the DRB1*0405-DQB1*0302 haplotype (RR = 33.7, Pc < 0.002) was 48 and 168 times higher than those conferred by the DRB1*0403-DQB1*0302 and DRB1*0406-DQB1*0302 haplotypes, respectively, suggesting that the protection conferred by DRB1*0403 and 0406 is dominant over DQB1*0302. The strong linkage disequilibrium observed between DQB1*0302 and DRB1*0403(0406) can thus explain the surprising finding that the frequency of DQB1*0302 was not significantly increased in the Chinese IDDM patients (RR = 0.9). Because the DRB1*0405-DQB1*0302 haplotype (RR = 33.7) conferred higher susceptibility than the DRB1*0405-DQB1*0401 (RR = 2.5) or DRB1*0405-DQB1*0301 (RR = 2.1) haplotypes, DQB1*0302 is indeed a susceptibility factor, while both DQB1*0301 and DQB1*0401 may confer protection against IDDM. The increased frequency of the protective DQB1*0401 allele in patients compared to controls is due to linkage disequilibrium between DRB1*0405 and DQB1*0401. Interestingly, the previously demonstrated protective effect of DQB1*0602 was not very strong in the Chinese (RR = 0.4). Our results suggested that HLA-encoded susceptibility to IDDM is determined by the combined effects of all DR and DQ molecules present in an individual. Therefore, the genotypic combinations of DR and DQ genes as well as their linkage disequilibria can influence IDDM susceptibility. At least four DR and DQ molecules conferring high susceptibility (DRB1*0301, DRB1*0405, and DQ alpha/beta 0301/0201 and 0301/0302) occur at high frequency in the Chinese population. However, linkage disequilibria between highly susceptible DR and protective DQ or vice versa (e.g., DRB1*0405-DQB1*0301[0401] and DRB1*0403[0406]-DQB1*0302) are probably responsible for the lower incidence of IDDM in the Chinese.

Characterization of protein production by caprine placental membranes: identification and immunolocalization of retinol-binding protein

Caprine chorion, allantois and amnion from days 23, 28, 35, 39 and 45, and yolk sac from day 23 of pregnancy were isolated by dissection and cultured for 24 h in modified minimum essential medium in the presence of [35S] methionine. De novo-synthesized proteins released into the culture medium were analyzed by two-dimensional PAGE and fluorography. Patterns of protein production by these isolated extraembryonic membranes remained relatively unchanged from days 23 to 45 of pregnancy. Electrophoretic profiles of proteins synthesized by allantois and amnion were identical but distinct from that produced by chorion. Yolk sac was the major source of serum-like proteins. An acidic (pI 5.3-6.3) 22 kDa protein, which consisted of four isoelectric variants, was produced by all extraembryonic membranes and demonstrated to immunoreact with antiserum produced against bovine placental retinol-binding protein (RBP). Limited N-terminal sequence analysis of one major isoform indicated that the protein had complete homology with bovine RBP over the first 15 amino acids. Immunoreactive RBP was localized in epithelial cells lining the chorion, allantois and amnion. In this study, we have characterized and compared protein production by isolated extraembryonic membranes through days 23 to 45 of pregnancy and identified the 22 kDa protein as caprine RBP of placental origin.

Removing a large submucous fibroid hysteroscopically with the two-resectoscope method

Hysteroscopic myomectomy was performed in 25 patients using resectoscopes of two different sizes because of large submucous fibroids causing severe menorrhagia and anemia. The cervix was softened and dilated by inserting a laminaria tent the night before the operation. During the procedure a 7-mm resectoscope was first used to cut the pedicle to a size smaller than 10 mm. A sessile myoma was resected into a pedunculated myoma, and its body resected with a 9-mm resectoscope. The smaller portions were removed with a pair of forceps. Simultaneous ultrasonography was used to monitor the procedure. Specimen weights ranged from 50 to 145 g (mean 78.5 g). The operation time was 13 to 118 minutes (mean 49 min). No complications were encountered, other than a cervical laceration caused by forceps. Postoperatively, 22 patients had improvement of menorrhagia and anemia. Three women underwent the same procedure due to recurrence of the fibroid; two had full-term deliveries. Our method has proved to be safe and efficient for treatment of a sessile or large submucous fibroid.