Assessment of denaturing high-performance liquid chromatography (DHPLC) in screening for mutations in connexin 26 (GJB2)

Mutations in the gene GJB2 encoding connexin 26 (Cx26), a gap junction protein, have been shown to be responsible for a majority of recessive nonsyndromic hereditary hearing impairment in children. Over 60 different mutations in Cx26 have been reported. To obviate the need for direct sequencing of each specimen, a variety of screening techniques have been used to detect mutations in Cx26. However, each of these methods has significant shortcomings including expense, time consumption, and limited sensitivity. Denaturing high-performance liquid chromatography (DHPLC) has been recently introduced as a rapid and highly sensitive method of detecting sequence alterations. We have assessed the efficacy of DHPLC as a screening assay for detecting mutation in Cx26 coding region in 154 patients with hereditary hearing impairment. The GJB2 coding exon was amplified in one or two fragments, analyzed by DHPLC, and sequenced. Sequence analysis identified sequence variations in 34 patients concordant with abnormal DHPLC results. Three novel Cx26 mutations were identified: a single base pair substitution 511G>A, a 4 bp insertion 504insAACG, and a 3 bp deletion 358delAGG in three unrelated patients. In 120 patients with normal Cx26 sequence, DHPLC was normal. These results yield sensitivity and specificity of 100% for DHPLC-based detection of Cx26 mutations, and demonstrate that DHPLC is a highly sensitive and specific method of screening for sequence variations in Cx26 that is time and labor efficient. Further, our experience suggests that DHPLC screening alone followed by DNA sequencing only when DHPLC is abnormal may be adequate for identification of all sequence alterations in Cx26.

[A comparison of the kinetic characters of NT-3, NT-4 and BDNF retrogradely transported in facial nerve]

OBJECTIVE

To compare the kinetic characters of retrograde transport of neurotrophin-3 (NT-3), neurotrophin-4 (NT-4) and brain-derived neurotrophin factor (BDNF) in facial nerve.

METHODS

Radioactive tracer technique was used. After one lateral facial nerve trunk of adult rabbit was transected, a silicone chamber was inserted between the stumps, and 3.7 MBq of 125I-NT-3 or 125I-NT-4 or 125I-BDNF or 125I-HSA was administered into the chamber. At different time-points after injection, the facial nerve trunk and facial nerve motor neurone of brain-stem were collected and the uptake rates were measured. The kinetic parameters of each labeled compound were calculated using 3P87 program of kinetics.

RESULTS

The transport amount of neurotrophin retrogradely transported by facial nerve is NT-3 > BDNF > NT-4 (P < 0.05), the transport rate is NT-4 > NT-3 > BDNF (P < 0.05).

CONCLUSION

The findings could serve as the kinetic characters of retrograde transport of neurotrophins.

A 3.1-kb genomic fragment of Bacillus subtilis encodes the protein inhibiting growth of Xanthomonas oryzae pv. oryzae

AIMS

To clone genes of Bacillus subtilis encoding peptides that inhibit the growth of Xanthomonas orzae pv. oryzae (Xoo).

METHODS AND RESULTS

A 3.1-kb DNA fragment from B. subtilis SO113 encoding peptides that inhibit the growth of Xoo (anti-Xoo, showing an inhibition zone) was isolated from a plasmid library of B. subtilis 6 GM15. Sequence analysis revealed that it contained three complete open reading frames (ORFs): ybcO, ybcS and a novel ORF designated ybcPQ. Deleting the last 96 bp of ybcS from the plasmid eliminated the anti-Xoo activity, suggesting that ybcS is required for producing the anti-Xoo activity. However, no anti-Xoo activity could be detected for the plasmid with ybcS alone. Further analysis showed that ybcO, at least, was also required to obtain the anti-Xoo activity.

CONCLUSIONS

A fragment of B. subtilis has been cloned that expresses an anti-Xoo activity that requires ybcS and ybcO.

SIGNIFICANCE AND IMPACT OF THE STUDY

These genes could be useful for the genetic engineering of resistance to rice bacterial diseases and for the design of new anti-Xoo biocontrol agents.

The three-dimensional structure of the C-terminal DNA-binding domain of human Ku70

The proteins Ku70 (69.8 kDa) and Ku80 (82.7 kDa) form a heterodimeric complex that is an essential component of the nonhomologous end joining DNA double-strand break repair pathway in mammalian cells. Interaction of Ku with DNA is central for the functions of Ku. Ku70, which is mainly responsible for the DNA binding activity of the Ku heterodimer, contains two DNA-binding domains. We have solved the solution structure of the Ku80-independent DNA-binding domain of Ku70 encompassing residues 536-609 using nuclear magnetic resonance spectroscopy. Residues 536-560 are highly flexible and have a random structure but form specific interactions with DNA. Residues 561-609 of Ku70 form a well defined structure with 3 alpha-helices and also interact with DNA. The three-dimensional structure indicates that all conserved hydrophobic residues are in the hydrophobic core and therefore may be important for structural integrity. Most of the conserved positively charged residues are likely to be critical for DNA recognition. The C-terminal DNA-binding domain of Ku70 contains a helix-extended strand-helix motif, which occurs in other nucleic acid-binding proteins and may represent a common nucleic acid binding motif.

Positional cloning of heart and soul reveals multiple roles for PKC lambda in zebrafish organogenesis

BACKGROUND

The Par-3/Par-6/aPKC complex is a key regulator of cell polarity in a number of systems. In Drosophila, this complex acts at the zonula adherens (adherens junctions) to establish epithelial polarity and helps to orient the mitotic spindle during asymmetric neuroblast divisions. In MDCKII cells, this complex localizes to the zonula occludens (tight junctions) and appears to regulate epithelial polarity. However, the in vivo role of this complex during vertebrate embryogenesis is not known, due to the lack of relevant mutations.

RESULTS

We have positionally cloned the zebrafish heart and soul (has) mutation, which affects the morphogenesis of several embryonic tissues, and show that it encodes atypical protein kinase C lambda (aPKC lambda). We find that loss of aPKC lambda affects the formation and maintenance of the zonula adherens in the polarized epithelia of the retina, neural tube, and digestive tract, leading to novel phenotypes, such as the formation of multiple lumens in the developing intestine. In addition, has mutants display defects in gut looping and endodermal organ morphogenesis that appear to be independent of the defects in epithelial polarity. Finally, we show that loss of aPKC lambda leads to defects in spindle orientation during progenitor cell divisions in the neural retina.

CONCLUSIONS

Our results show that aPKC lambda is required for the formation and maintenance of the zonula adherens during early epithelial development in vertebrates and demonstrate a previously undescribed yet critical role for this protein in organ morphogenesis. Furthermore, our studies identify the first genetic locus regulating the orientation of cell division in vertebrates.

[Study on effect of Astragalus injection in treating congestive heart failure]

OBJECTIVE

To observe the clinical efficacy and side-effects of Astragalus Injection (AI) in treating congestive heart failure (CHF).

METHODS

Eighty-three patients of CHF with heart function of II-IV grade assessed by NYHA (New York Heart Association) classification were randomly divided into 2 groups. The 42 patients in the treated group were treated with AI 40 ml (equivalent to 80 g crude drug) by adding in 5% glucose solution 500 ml for intravenous dripping, once a day and the 41 patients in the control group were treated by nitrolingual injection 15 mg by adding in 5% glucose solution 500 ml for intravenous dripping once a day. The therapeutic course in both groups was 2 weeks and the patients were followed-up for 1-6 months.

RESULTS

The clinical heart function improvement rate and the total effective rate in the treated group after 1 month treatment were 26.2% and 78.6%, and after 6 months were 34.2% and 81.6% respectively, which were superior to those in the control group significantly (P < 0.05 or P < 0.01). The levels of left ventricular ejection fraction (LVEF), fractional shortening of left ventricular short axis (FS), the ratio of maximum blood flow between the advanced and early atrial systole (E/A), stroke volume (SV), cardiac output (CO) and the cardiac index (CI) were all improved in both groups (P < 0.01 or P < 0.05), but better improvement was shown in the treated group. Follow-up study showed that the incidence of cardiac event was lower in the treated group than that in the control group (P < 0.05).

CONCLUSION

AI can be took as one of the important auxiliary drugs for treatment of CHF especially in severe cases.

The de-ubiquitinating enzyme Unp interacts with the retinoblastoma protein

The ubiquitin pathway is involved in the proteolytic turnover of many short-lived cellular regulatory proteins. Since selective degradation of substrates of this system requires the covalent attachment of a polyubiquitin chain to the substrates, degradation could be counteracted by de-ubiquitinating enzymes (or isopeptidases) which selectively remove the polyubiquitin chain. Unp is a human isopeptidase with still poorly understood biological functions. Here, we show that cellular Unp specifically interacts with the retinoblastoma gene product (pRb).

[A study of on the transport of neurotrophin-4 in facial nerve]

OBJECTIVE

This is a study on the transport information of neurotrophin-4 (NT-4) in facial nerve using radioactive tracer technique.

METHODS

After one lateral facial nerve trunk of adult rabbit was transected, a silicone chamber was inserted between the stumps, and 7.4 MBq of 131I-NT-4 was administered into the chamber. At the distinct moment of post-injection, the head of one rabbit was imaged at coronary position, the bilateral facial nerve trunk and brain-stem of the others were collected and counted respectively. After 1 mg of brain-derived neurotrophic factor (BDNF) and 7.4 MBq of 131I-NT-4 were administered into the chamber of one rabbit, the rabbit was imaged at coronary position of head at distinct moment.

RESULTS

5.08% of 131I-NT-4 was transported into facial nerve trunk at 4 h of post-injection. 131I-NT-4 presented high peak in facial nerve trunk during the period of 8, 12 h, the peak values were 20.58% and 22.74% respectively. 34.75% and 45.57% of 131I-NT-4 were transported into the brain-stem of experimental side at 8 h and 12 h respectively. The transport of 131I-NT-4 was markedly restrained by BDNF in facial nerve.

CONCLUSION

NT-4 displays a receptor-mediated retrograde transport in facial nerve.

Body mass index and the risk of recurrent coronary events following acute myocardial infarction

Although excess adiposity appears to increase the risk of coronary heart disease in the general population, its importance in patients with established coronary disease is less defined. We evaluated a population-based inception cohort of survivors to hospital discharge following first acute myocardial infarction (AMI) (n = 2,541) to assess the association between body mass index (BMI) and the risk of recurrent coronary events and to explore the mechanisms for this relation. Using Cox proportional-hazards regression, we assessed the risk of recurrent coronary events associated with levels of adiposity as defined by BMI and then investigated potential mechanisms through which adiposity conferred risk by examining how adjustment for diabetes mellitus, systemic hypertension, and dyslipidemia affected the association. Forty-one percent of the cohort were overweight (BMI 25 to 29.9), and 27.8% were obese (BMI > or =30). After adjustment for other risk factors, the risk of recurrent coronary events (n = 418) increased as BMI increased, especially among those who were obese. Using a BMI of 16 to 24.9 as the reference group, for mildly overweight patients (BMI 25 to 27.4), the relative risk (RR) was 0.93 (95% confidence interval [CI] 0.70 to 1.24); it was 1.16 for more severe overweight patients (BMI 27.5 to 29.9; 95% CI 0.87 to 1.55). For patients with class I obesity (BMI 30 to 34.9), the RR was 1.49 (95% CI 1.12 to 1.98), and for class II to III obesity (BMI > or =35), the RR was 1.80 (95% CI 1.30 to 2.48). We estimated that clinical measurements of diabetes, hypertension, and dyslipidemia explained approximately 43% of this risk. Thus, excess adiposity as measured by BMI was associated with an increased risk of recurrent coronary events following AMI, particularly among those who were obese.

[Pilot study on mutations of p53 gene in laryngeal carcinoma]

OBJECTIVE

To determine the characteristic and frequency of the point mutation of p53 gene.

METHODS

22 cases of laryngeal squamous cell carcinoma (LSCC) with positive expression of mutant p53 protein and 2 cases of normal laryngeal epithelium as control were examined by means of polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP), single strand conformation polymorphism (SSCP) and DNA sequencing analyses.

RESULTS

3 cases of LSCC had the point mutation on codons 248, 250 and 254 of exon 7 in p53 gene. None of the cases had the point mutation on codon 249.

CONCLUSION

These findings suggest that the point mutation on codon 249 of exon 7 in p53 gene may be uncommon in LSCC. SSCP and DNA sequencing analyses are sensitive and rapid methods for detecting p53 gene mutation.

[Classification study on the marshland in endemic areas of Schistosoma japonicum using satellite TM image data]

OBJECTIVE

To create a land cover map of the marshland region of Schistosoma Japonicum using satellite TM data from Chayegang, Jiangxi Province.

METHODS

Satellite data of three TM bands, namely TM3, TM4 and TM5, were selected to be used in classification study with Principal Components Analysis. Then TM satellite images were applied to false color composite and unsupervised classification with computer software to manage the TM data. Finally the resulting clusters were identified by undertaking site visits and a systematic sampling snail survey was also carried out in the study area in April, 2000.

RESULTS

Three land cover classes were generated, including class 1, the carex zone that is both the dominant vegetation and main snail habitats of the study area. Based on the snail survey in the spring of 2000, the live snail density and infectious snail density of the carex zone were 2.51/0.11 m2 and 0.006 9/0.11 m2, respectively. The infection rate of the snail was 0.28%. No snail was found in land cover class 3, the mixed vegetation, because the altitude of this area is either above 17 m or under 14 m and therefore the vegetation in this area is unsuitable for snails to survive.

CONCLUSION

Remote sensing can contribute the study on the distribution of snail habitats and become a promising epidemiological study method for schistosomiasis and other ecological diseases.

Dynamics of the Mrf-2 DNA-binding domain free and in complex with DNA

Mrf-2 is a member of a new class of DNA-binding proteins known as the AT-rich interaction domain family or ARID. Chemical shift indices and characteristic NOE values indicate that the three-dimensional structure of the Mrf-2 ARID in complex with DNA is nearly identical to that of the free protein. The backbone dynamics of the Mrf-2 domain free and in complex with DNA have been characterized by (15)N NMR relaxation measurements and model-free analysis. Chemical shift perturbations and dynamic studies suggest that two flexible interhelical loops, the flexible C-terminal tail, and one alpha-helix are involved in DNA recognition, indicating the importance of protein dynamics in DNA binding. Some well-structured regions, in particular the putative DNA-contacting helix, in Mrf-2 show a decrease in the order parameters (S(2)) upon complex formation. The less well-structured loops and the unstructured C-terminus show reduced flexibility upon DNA binding. In addition, the model-free analysis indicates motions on the picosecond to nanosecond and micro- to millisecond time scales at the DNA-binding surface of the bound Mrf-2 ARID, suggesting a model where interactions between the protein and DNA are highly dynamic.

Effect of dietary K intake on apical small-conductance K channel in CCD: role of protein tyrosine kinase

We have used Western blot to examine the expression of cSrc protein tyrosine kinase (PTK) and protein tyrosine phosphatase (PTP)-1D in the renal cortex, and the patch-clamp technique to determine the role of PTK in mediating the effect of dietary K intake on the small-conductance K (SK) channel in the cortical collecting duct (CCD). When rats were on a K-deficient (KD) diet for 1, 3, 5, and 7 days, the expression of cSrc increased by 40, 90, 140, and 135%, respectively. In contrast, the expression of cSrc in the renal cortex from rats on a high-K (HK) diet for 1, 2, and 3 days decreased by 40, 60, and 75%, respectively. However, the protein level of PTP-1D was not significantly changed by dietary K intake. The addition of 1 microM herbimycin A increased NP(o), a product of channel number (N) and open probability (P(o)) in the CCD from rats on a normal diet or on a KD diet. The increase in NP(o) was 0.30 (normal), 0.45 (1-day KD), 0.65 (3-day KD), 1.55 (5-day KD), and 1.85 (7-day KD), respectively. Treatment of the CCD with herbimycin A from rats on a KD diet increased NP(o) per patch from the control value (0.7) to 1.4 (1-day KD), 1.6 (3-day KD), 2.6 (5-day KD), and 3.5 (7-day KD), respectively. In contrast, HK intake for as short as 1 day abolished the effect of herbimycin A. Furthermore, the expression of ROMK channels in the renal cortex was the same between rats on a KD diet or on a HK diet. Moreover, treatment with herbimycin A did not further increase NP(o) in the CCDs from rats on a HK diet. We conclude that dietary K intake plays a key role in regulating the activity of the SK channels and that PTK is involved in mediating the effect of the K intake on channel activity in the CCD.

Risk of recurrent coronary events in relation to use and recent initiation of postmenopausal hormone therapy

BACKGROUND

The finding from the Heart and Estrogen/Progestin Replacement Study (HERS) of increased coronary risk restricted to the first year after starting postmenopausal hormone therapy raises new questions about the role of hormone therapy in women with coronary heart disease. We assessed the risk of recurrent myocardial infarction or coronary heart disease death associated with the use and recent initiation of hormone therapy in women who survived a first myocardial infarction.

METHODS

The setting for this population-based inception cohort study was Group Health Cooperative, a health maintenance organization. We studied 981 postmenopausal women who survived to hospital discharge after their first myocardial infarction between July 1, 1986, and December 31, 1996. We obtained information on hormone use from the Group Health Cooperative computerized pharmacy database and identified recurrent coronary events by medical record review.

RESULTS

During median follow-up of 3.5 years, there were 186 recurrent coronary events. There was no difference in the risk of recurrent coronary events between current users of hormone therapy and other women (adjusted relative hazard [RH], 0.96; 95% confidence interval [CI], 0.62-1.50). Relative to the risk in women not currently using hormones, there was a suggestion of increased risk during the first 60 days after starting hormone therapy (RH, 2.16; 95% CI, 0.94-4.95) and reduced risk with current hormone use for longer than 1 year (RH, 0.76; 95% CI, 0.42-1.36).

CONCLUSION

These results are consistent with the findings from the HERS, suggesting a transitory increase in coronary risk after starting hormone therapy in women with established coronary heart disease and a decreased risk thereafter.

Androgen-driven prostate epithelial cell proliferation and differentiation in vivo involve the regulation of p27

Androgens control both growth and differentiation of the normal prostate gland. However, the mechanisms by which androgens act upon the cell cycle machinery to regulate these two fundamental processes are largely unknown. The cyclin-dependent kinase (cdk) inhibitor p27 is a negative cell cycle regulator involved in differentiation-associated growth arrest. Here, we investigate the role and regulation of p27 in the testosterone proprionate (TP)-stimulated regeneration of the ventral prostate (VP) of castrated rats. Continuous TP administration to castrated rats triggered epithelial cell proliferation, which peaked at 72 h, and then declined despite further treatment. Castration-induced atrophy of the VP was associated with a significant increase in p27 expression as compared with the VP of intact animals. Twelve hours after the initiation of androgen treatment, total p27 levels as well as its fraction bound to cdk2, its main target, significantly dropped in the VP of castrated rats. Thereafter, concomitantly to the induction of epithelial cell proliferation, the glandular morphology of VP was progressively restored at 48-96 h of TP treatment. During this period of the regenerative process, whereas both proliferating basal and secretory epithelial cells did not express p27, the protein was selectively up-regulated in the nonproliferating secretory epithelial compartment. This up-regulation of p27 expression was coincident with an increase in its association with, and presumably inhibition of, cdk2. At each time point of TP treatment, p27 abundance in the VP was inversely correlated with the level of its proteasome-dependent degradation activity measured in vitro in VP lysates, whereas only slight changes in the amount of p27 transcripts were detected. In addition, the antiandrogen flutamide blocked maximal TP-induced p27 degradation completely. Finally, the expression of skp2, the ubiquitin ligase that targets p27 for degradation, was seen to increase with androgen administration, preceding maximal proliferation and concomitantly to augmented p27 degradation activity. Taken together, our data indicate that androgens mediate both proliferation and differentiation signals in normal prostate epithelial cells in vivo, through regulation of p27.

Methylenetetrahydrofolate reductase polymorphisms increase risk of esophageal squamous cell carcinoma in a Chinese population

Methylenetetrahydrofolate reductase (MTHFR) plays a central role in folate metabolism that affects DNA methylation and synthesis. Because germ-line mutations at nucleotides 677 (C-->T) and 1298 (A-->C) in the MTHFR gene cause diminished enzyme activity, and aberrant DNA methylation is oncogenic, we examined the relationship between these two MTHFR polymorphisms and susceptibility to esophageal squamous cell carcinoma (ESCC) in 240 ESCC cases and 360 age- and sex-matched controls in northern CHINA: We found that the allele frequency of MTHFR 677T was significantly higher among cases than among controls (63% versus 41%, P < 0.001). Subjects with the 677TT genotype had a more than 6-fold increased risk of developing ESCC [adjusted odds ratio (OR), 6.18; 95% confidence interval (CI), 3.32-11.51] compared with those who had the 677CC genotype. Furthermore, the elevated ESCC risk associated with the 677 polymorphism was in an allele-dose relationship (trend test, P = 0.0001) with ORs of 1.00, 3.14 (95% CI, 1.94-5.08), and 6.18 (95% CI, 3.32-11.51) for the CC, CT, and TT genotype, respectively, after adjustment for age, sex, smoking status, and the MTHFR 1298 polymorphism. The allele frequency for the MTHFR 1298C was 14% among cases and 17% among controls. The 1298CC genotype was extremely rare in both controls (1.4%) and cases (2.9%) and was also associated with an elevated risk of ESCC (adjusted OR, 4.43; 95% CI, 1.23-16.02) compared with the 1298AA genotype, whereas the 1298AC genotype had no effect on the risk of ESCC. Thus, our findings support the hypothesis that genetic polymorphisms in the MTHFR gene may contribute to susceptibility to carcinogenesis of the esophagus in the at-risk Chinese population.

[Cluster analysis study on the marshland of Schistosoma Japonicum using satellite TM image data in Peng Lake, Jiangxi province]

OBJECTIVE

To create a category land cover map of the marshland region of Schistosoma Japonicum using satellite TM data.

METHODS

TM satellite images from Peng Lake of Jiangxi province were applied to the Cluster analysis. Then the resulting clusters were identified and reclassified by undertaking site visits.

RESULTS

Eight land cover classes were generated, including Carexspp Zone that was the snail habitat place.

CONCLUSION

Cluster analysis, which is a technique for the interpretation of remotely sensed imagery, could contribute to the study on the distribution of snail habitats and become a new tool for the epidemiological ecology study.

Thermally stable narrow-bandpass filter prepared by reactive ion-assisted sputtering

Thermal stabilities of three-cavity narrow-bandpass (NB) filters with high-index half-wave spacers and 78-102 layers of Ta(2)O(5) and SiO(2) prepared by reactive ion-assisted bipolar direct-current (dc) magnetron sputtering of tantalum and silicon targets, respectively, were investigated. Pure argon and pure oxygen were used as the sputtering gas and the reactant, respectively. The oxygen gas was introduced and ionized through the ion gun and toward the unheated BK7 glass substrate. The refractive indices of single-layer Ta(2)O(5) and SiO(2) films were 2.1 and 1.45, respectively, at 1550 nm, which were comparable with those of films prepared by other ion-assisted coating techniques. The moisture-resistant properties of the films were excellent as evidenced from the water-immersion test, implying that the packing density of the films was close to that of their bulk materials. The temperature-dependant wavelength shifts of the NB filters were <3 x 10(-3) nm/ degrees C at temperatures of <75 degrees C, indicating that the temperature-induced wavelength shift of the filter was <0.15 nm when the temperatures were raised from room temperature to 75 degrees C, which was compliant with Bellcore GR-1209-CORE generic requirements of NB filters used for optical-fiber communication systems.

The Fcgamma receptor IIIA-158F allele is a major risk factor for the development of lupus nephritis among Caucasians but not non-Caucasians

OBJECTIVE

To determine whether inheritance of Fcgamma receptor (FcgammaR) alleles conferring lower affinity for IgG binding increases the risk of developing lupus nephritis.

METHODS

We compared the frequency of low-affinity alleles of two FcgammaR polymorphisms (FcgammaRIIA and FcgammaRIIIA) among 235 patients with systemic lupus erythematosus (SLE) and proven nephritis (nephritis patients) and among 352 SLE patients with no evidence of renal disease (non-nephritis control subjects). The ethnic distribution of patients in the study was 49% Caucasian, 20% Hispanic, 17% Asian/Pacific Islander, 12% African American, and 2% from other ethnic groups. All patients were genotyped for the FcgammaRIIA-131R/H and FcgammaRIIIA-158V/F polymorphisms. We used contingency table analysis to compare allele and genotype distributions for nephritis patients and nonnephritis control subjects, including ethnic-specific strata. Multivariate logistic regression analyses included sex and disease duration as covariates.

RESULTS

Univariate and multivariate analyses demonstrated a striking association between the low-affinity FcgammaRIIIA-158F allele and FF genotype and the risk of nephritis among Caucasians, but not among non-Caucasians (multivariate odds ratio [OR] 2.6 for Caucasians with FF genotype), (P = 0.0017). This association was even stronger among Caucasians with severe nephritis (OR 4.4, P < 0.0001). In contrast, inheritance of the low-affinity FcgammaRIIA-131R allele (and RR genotype) was not associated with an increased risk of lupus nephritis among any of the ethnic groups examined.

CONCLUSION

The FcgammaRIIIA-158F allele is a major risk factor for the development of lupus nephritis among Caucasians, but not among non-Caucasians. These results suggest that ethnic variation is critical in defining the specific genetic factors underlying the pathogenesis of SLE, and they have important prognostic and therapeutic implications as well.

Hyperintense signal abnormality in subarachnoid spaces and basal cisterns on MR images of children anesthetized with propofol: new fluid-attenuated inversion recovery finding

BACKGROUND AND PURPOSE

MR imaging is the method of choice for pediatric neuroimaging. Sedation is often needed to suppress patient motion and ensure diagnostic image quality, and propofol is rapidly becoming the preferred anesthetic. The purpose of this study was to document a new finding on fast fluid-attenuated inversion recovery (fast-FLAIR) MR images of children anesthetized with propofol that can be mistaken for subarachnoid space pathologic abnormality.

METHODS

A retrospective analysis was conducted of 55 MR images of the brain for children who ranged in age from 1 week to 12 years. Forty-two patients received chloral hydrate, and 13 received propofol anesthetic. Multiplanar MR images were studied to detect the presence or absence of hyperintense signal (artifact) in the subarachnoid spaces and basal cisterns. The T1 values and null times of chloral hydrate, propofol, and CSF were determined in vitro at room temperature by using an inversion recovery pulse sequence at 1.5 T.

RESULTS

The fast-FLAIR images of all 13 patients who received propofol had hyperintense signal abnormality. For 10 (77%) of 13 patients, this artifact was in the basal cisterns and subarachnoid spaces overlying the brain convexity. For three (23%) of 13 patients, this artifact was in the convexity region only. Two patients underwent follow-up MR imaging with a nonpropofol anesthetic agent, and the artifact resolved. None of the images of the children who received chloral hydrate had this artifact. The T1 value of chloral hydrate was 0.2 s, of propofol was 1.86 s, and of CSF was 2.32 s at room temperature.

CONCLUSION

The fast-FLAIR images of children anesthetized with propofol have artifactual hyperintense signal in the basal cisterns and subarachnoid spaces, and this artifact mimics disease of the subarachnoid space. The T1 value of propofol approaches that of CSF. Depending on the chosen null time, there may be incomplete nulling of signal coming from propofol. To account for this observation, other possible causes include increased CSF pulsation in children creating motion artifact, changes in arterial oxygen concentration intrinsic to propofol or related to the supplemental oxygen normally administered, or changes in CSF protein levels related to propofol binding to proteins for uptake into CSF.

[Preliminary study of the facial nerve regeneration in the chamber: the influence of myelin basic protein]

OBJECTIVE

To study the role of exogenous myelin basic protein(MBP) in neural repairment.

METHODS

Adult New Zealand rabbits were employed in vivo preparation. A 12 microL nerve growth chamber was created by suturing the proximal and distal stumps of a transected facial never (FN) trunk into a tube. The regenerated nerves within the chambers were dissected and fixed for histological studies with light microscope at 4, 6 and 8 weeks respectively following the surgery.

RESULTS

Morphological analysis of nerves showed no difference between the MBP and control group in the size of the regeneration FN within the chambers, diameters of myelinated axons, thickness of myelin sheath and number of myelin axons grew into the distal end of chamber at 4 weeks. At 6 and 8 weeks after operation, the MBP group showed a more mature-appearance regenerative nerve comparing to control group. Especially, the enhancement of maturation in the regeneration axons was very noticeable at 6 weeks.

CONCLUSION

The study showed that pharmacological administration of exogenous MBP within a chamber at the time of entubational nerve repair enhances regeneration of myelinated axons across the sectioned ends of FN.

Molecular cloning, modeling, and localization of rat type 10 17beta-hydroxysteroid dehydrogenase

Rat and mouse complementary DNAs of type 10 17beta-hydroxysteroid dehydrogenase were cloned and sequenced. The mouse cDNA clone's sequence corrected the previously published nucleotide and amino acid sequence of mouse endoplasmic reticulum-associated beta-amyloid-binding protein. A subunit of the rat enzyme consists of 261 amino acid residues with a calculated molecular mass of 27250 Da. Compared with its human counterpart, rat 17betaHSD type 10 shows 88% identity. Mouse 17betaHSD type 10 is composed of 261 amino acid residues with a calculated molecular mass of 27274 Da. There is 95% identity between the two rodent enzymes. A stereostructure model of rat 17betaHSD type 10 was constructed based on its amino acid sequence. Similar to human type 10 17betaHSD, the rodent enzymes also displayed relatively higher 3alphaHSD activity than 17betaHSD activity. Intracellular localization of rat 17betaHSD type 10 has been determined by subcellular fractionation and confocal microscopy studies. The results unequivocally establish that this is a nuclear gene-encoded mitochondrial enzyme, and that this 17betaHSD is not associated with the endoplasmic reticulum. The unique location distinguishes type 10 from other types of 17beta-hydroxysteroid dehydrogenases.

CYP 1A1 polymorphism and risk of lung cancer in relation to tobacco smoking: a case-control study in China

The impact of genetic polymorphisms in CYP1A1 on susceptibility to lung cancer has received particular interest in recent years since this enzyme plays a central role in activation of major classes of tobacco carcinogens. Several polymorphisms in the CYP1A1 locus have been identified and their genotypes appear to exhibit population frequencies that depend on ethnicity. We have assessed the role of CYP1A1 genotype in lung cancer risk in the Chinese population via a case-control study. Three polymorphisms, m1 (MSP:I), m2 (exon 7 Ile-->Val) and m4 (exon 7 Thr-->Asn), were determined by PCR-RFLP in 404 controls and 217 lung cancer cases. While no polymorphic alleles were detectable in the m4 site among our study subjects, the allele frequencies for CYP1A1 m1 and CYP1A1 m2 were found to be 35.6 and 25.6% among controls, compared with 42.6 and 34.2% among cases. Multivariate analysis showed an elevated risk for lung cancer in subjects having at least one m1 allele [odds ratio (OR) = 2.0, 95% confidence interval (CI) = 1.4-2.8] or having at least one m2 allele (OR = 1.9, 95% CI = 1.3-2.7). However, this increased risk was limited to squamous cell carcinoma (SCC), but not adenocarcinoma or other histological types of lung cancer. Stratified analysis indicated a multiplicative interaction between tobacco smoking and variant CYP1A1 m1 genotypes on the risk of SCC. The ORs of SCC for the variant CYP1A1 m1 genotype, tobacco smoking and both factors combined were 2.8, 9.1 and 29.9, respectively. When the data was stratified by the pack-year values, this joint effect was consistent and stronger among the heaviest smokers. The interaction between tobacco smoking and the variant CYP1A1 m2 genotypes followed the same pattern. Our findings support the conclusion that CYP1A1 m1 and CYP1A1 m2 polymorphisms are associated with smoking-related lung cancer risk in Chinese.

RR interval variation, the QT interval index and risk of primary cardiac arrest among patients without clinically recognized heart disease

AIMS

Autonomic tone influences RR interval variation (RRV) and the heart rate-corrected QT interval index (QTI). Together, QTI and RRV may improve characterization of sympathovagal control and estimation of risk of primary cardiac arrest. We therefore examined effects of QTI and short-term RRV from standard, 12-lead electrocardiograms on risk of primary cardiac arrest among persons without clinically recognized heart disease.

METHODS AND RESULTS

We analysed data from a case-control study of risk factors for primary cardiac arrest among enrollees in a large health plan. Cases (n=505) were enrollees aged 18 to 79 years without history of heart disease who had primary cardiac arrest between 1980 and 1994. Controls (n=529) were a demographically similar, stratified random sample of enrollees. We determined enrollee characteristics from ambulatory medical records, QTI and RRV from standard, 12-lead electrocardiograms, and medication use from automated pharmacy files. Low and high values of QTI and RRV were designated as the first and fifth quintiles of QTI (96% and 107%) and RRV (35 ms and 120 ms) among controls. In a model adjusting for clinical predictors of primary cardiac arrest, RRV modified the association between QTI and risk of primary cardiac arrest (P=0.05). Compared to high RRV and low QTI, the risk of primary cardiac arrest (odds ratio [95% CI]) was 0.95 [0.73-1.23] at low RRV and QTI, 1.23 [0.97-1.57] at high RRV and QTI, and 1.55 [1.16-2.06] at low RRV and high QTI. Risk remained elevated after adjustment for other electrocardiographic predictors and medication use.

CONCLUSION

Autonomic dysfunction, characterized by high QTI and low RRV on the standard, 12-lead electrocardiogram, is associated with an increased risk of primary cardiac arrest among persons without clinically recognized heart disease.