Comparison of Anterior Segment Biometric Measurements between Pentacam HR and IOLMaster in Normal and High Myopic Eyes

Purpose

To compare the anterior chamber depth (ACD), keratometry (K) and astigmatism measurements taken by IOLMaster and Pentacam HR in normal and high myopic (HM) eyes.

Design

A prospective observational case series.

Methods

Sixty-six normal eyes and 59 HM eyes underwent ACD, keratometry and astigmatism measurements with both devices. Axial length (AL) was measured on IOLMaster. The interdevice agreement was evaluated using the Bland-Altman analysis and paired t-test. The correlations between age and AL & ACD were analyzed. Vector analysis was used to compare astigmatism measurements.

Results

The ACD from IOLMaster and Pentacam HR was different for the normal group (P = 0.003) but not for the HM group (P = 0.280). IOLMaster demonstrated higher steep K and mean K values than Pentacam HR for both normal and HM groups (P<0.001 for all). IOLMaster also have higher flat K values for the HM groups (P<0.001) but were statistically equivalent with Pentacam HR for the normal group (P = 0.119) IOLMaster and Pentacam HR were different in astigmatism measurements for the normal group but were statistically equivalent for the HM group. For the normal group, age was negatively correlated with AL, IOLMaster ACD and Pentacam HR ACD (r = -0.395, P = 0.001; r = -0.715, P < 0.001; r = -0.643, P < 0.001). For the HM group, age was positively correlated with AL but negatively correlated with IOLMaster ACD and Pentacam HR ACD (r = 0.377, P = 0.003; r = -0.392, P = 0.002; r = -0.616, P < 0.001).

Conclusions

The IOLMaster and Pentacam HR have significant difference in corneal power measurements for both normal and HM groups. The two instruments also differ in ACD and astigmatism measurement for the normal group. Therefore, a single instrument is recommended for studying longitudinal changes in anterior segment biometric measurements. Age should be considered as an influencing factor for both AL and ACD values in the normal and HM group.     

Comparative Absorption Readings Obtained with Spectrophotometers of Various Types

One of the most important means of identifying a dye is by spectrophotometry. This method has been used as a criterion for judging the samples of stains submitted by manufacturers ever since the certification plan for biological stains was adopted. All specifications that have been drawn up for biological stains, such as those given in the 7th edition of the National Formulary, have included spectrophotometry requirements.     

高分辨率熔解曲线分析技术检测结核分枝杆菌的耐药性

目的:探讨高分辨率熔解曲线分析(High resolution melting,HRM)技术检测结核分枝杆菌耐药突变位点的可行性。方法:对218株结核分枝杆菌进行利福平(RFP)和异烟肼(INH)的药物敏感性测定,并进行耐药基因位点的PCR扩增和测序,同时采用HRM方法检测RFP和INH耐药基因位点情况,分析HRM的敏感性和特异性。结果:218株结核分枝杆菌药敏试验结果显示,有106株(48.6%)对RFP耐药,100株(45.9%)对INH耐药,81株(37.4%)对RFP和INH均耐药。测序发现,101株(46.3%)存在RFP耐药基因的突变,107株(49.1%)存在INH耐药基因的突变。HRM检测结果显示,100株(45.9%)存在RFP耐药基因的突变,103株(47.2%)存在INH耐药基因的突变。分别以药敏试验和测序结果为标准,HRM检测RFP耐药的敏感性为94.3%(100/106)和99.0%(100/101);特异性为97.3%(109/112)和100%(117/117);INH耐药的敏感性为97.0%(97/100)和98.1%(103/105);特异性为97.3%(109/112)和100%(113/113)。结论:HRM快速检测结核分枝杆菌耐药具有较高的特异性和灵敏度,能够满足临床需求。     

New High Resolution Pollen Records from Two Lakes in Xizang (Tibet)

Studies on the pollen from cores of Lake Hidden (29~48.77' N, 92~22.37' E) and Ren Co (30%3.97'N, 96~40.97'E) in Southeast Xizang (Tibet) showed climatic changes and the evolution of vegetation since the last Glacial Maximum (LGM). Before 16 ka BP pollen assemblages were dominated by Chenopodiaceae (20% -50% ) and Artemidis (10% ~ 30% ) and pollen influx values were very low from Lake Ren Co in Basu county. The vegetation around the lake was probably a desert-steppe during the LGM. The data also suggest that the climate in the Basu area was cold and dry during the LGM and the last glacial time. The mean annual temperature was probably 4 ~ 6 ℃ colder than the present, and the mean annual precipitation was only 250 mm, about 40% of the present. The Southwest monsoon became stronger from 12 ka BP to 6 ka BP reaching its acme by 7 ka BP, but weakened gradually from 5 ka BP to the present. The paleovegetation was dominantly forest or forest-meadow around Lake Hidden and Ren Co during the 9.2 ~ 5 ka BP. The mean temperature in January was probably 2 ~ 3 ℃ higher than the present, and the mean annual precipitation was 100 mm more than the present. The timing of vegetational and climatic changes based on pollen records generally supports the results of global climatic-model experiments that predict a strengthened monsoon system during the early to middle Holocene followed by a weakened monsoon system.     

High Resolution Melting Analysis for Evaluation of mir-612 (Rs12803915) Genetic Variant with Susceptibility to Pediatric Acute Lymphoblastic Leukemia

Background:Acute lymphoblastic leukemia (ALL) is a highly heterogeneous malignancy that accounts for nearly 75% of leukemias in children. While the exact mechanism of ALL is not fully understood, some genetic variants have been implicated as associated with ALL susceptibility. The association between some genetic variants in miRNA genes and ALL risk has been described previously. A previous study suggested that mir-612 rs12803915 G> A may be associated with pediatric ALL risk. High-resolution melting (HRM) analysis is a reliable method that can be applied for polymorphism detection.Methods:This retrospective study was performed on 100 B-ALL patients (52 males and 48 females; age 4.6 ± 3.2 years) and 105 age- and sex-matched healthy controls (48 males and 57 females; age 5.1 ± 3 years). We used HRM to identify mir-612 rs12803915 genotypes. Sanger sequencing was applied to validate the HRM results.Results:High resolution melting analysis was used to genotype the mir-612 rs12803915 polymorphism. We found no association between rs12803915 allele A and B-ALL risk in any inheritance models (p> 0.05).Conclusion:HRM is a suitable method to detect SNP rs12803915 in the mir-612 gene; however, we found no significant association between the rs12803915 polymorphism and ALL risk.Key Words: Childhood ALL, Hsa-mir-612, High-Resolution Melting (HRM), MicroRNA, Polymorphism     

用超常的复性温度改善小麦RA PD分析的效果

用38～66℃不同复性温度处理,比较了18条随机引物的扩增结果.发现复性温度在40～50℃之间均有数量不等的扩增产物,不同引物的最高复性温度不同,有些引物用60℃以上的复性温度仍有扩增产物.一些在35～38℃的复性温度下非特异性产物较多的引物,通过大幅度提高复性温度,能提高扩增产物的特异性,获得清晰的RAPD带型。 Abstract:To decrease nonspecific products and obtain clear RAPD patterns,18 10- mer random primers were tested at different annealing temperatures.The results indicated that all the amplification can be performed when the annealing temperature is in the range of 40~50℃.There were a few primers with which the amplification was still performed when the annealing temperature is above 60℃.By using high annealing temperatures,some primers which produce more nonspecific product at the annealing temperatures of 35~38℃ could generate reproducible and distinct bands.     

用超常的复性温度改善小麦RAPD分析的效果

用38－66℃不同复性温度处理,比较了18条随机引物的扩增结果。发现复性温度在40－50℃之间均有数量不等的扩增产物,不同引物的最高复性温度不同,有些引物用60℃以上的复性温度仍有扩增产物。一些在35－38℃的复性温度下非特异产物较多的引物,通过大幅度提高复性温度,能提高扩增产物的特异性,获得清晰的RAPD带型。     

用荧光原位杂交技术构建高分辨率的DNA物理图谱

用荧光原位杂交技术构建高分辨率的ＤＮＡ物理图谱钟筱波ＰａｕｌＦ．ＦｒａｎｓｚＪ．ＨａｎｓｄｅＪｏｎｇＰｉｍＺａｂｅｌ（荷兰瓦赫宁根农业大学分子生物学系）ＨｉｇｈＲｅｓｏｌｕｔｉｏｎＰｈｙｓｉｃａｌＭａｐｐｉｎｇｂｙＦｌｕｏｒｅｓｃｅｎｃｅｉｎｓｉｔｕ...     

High Resolution Typing by Whole Genome Mapping Enables Discrimination of LA-MRSA (CC398) Strains and Identification of Transmission Events

After its emergence in 2003, a livestock-associated (LA-)MRSA clade (CC398) has caused an impressive increase in the number of isolates submitted for the Dutch national MRSA surveillance and now comprises 40% of all isolates. The currently used molecular typing techniques have limited discriminatory power for this MRSA clade, which hampers studies on the origin and transmission routes. Recently, a new molecular analysis technique named whole genome mapping was introduced. This method creates high-resolution, ordered whole genome restriction maps that may have potential for strain typing. In this study, we assessed and validated the capability of whole genome mapping to differentiate LA-MRSA isolates. Multiple validation experiments showed that whole genome mapping produced highly reproducible results. Assessment of the technique on two well-documented MRSA outbreaks showed that whole genome mapping was able to confirm one outbreak, but revealed major differences between the maps of a second, indicating that not all isolates belonged to this outbreak. Whole genome mapping of LA-MRSA isolates that were epidemiologically unlinked provided a much higher discriminatory power than spa-typing or MLVA. In contrast, maps created from LA-MRSA isolates obtained during a proven LA-MRSA outbreak were nearly indistinguishable showing that transmission of LA-MRSA can be detected by whole genome mapping. Finally, whole genome maps of LA-MRSA isolates originating from two unrelated veterinarians and their household members showed that veterinarians may carry and transmit different LA-MRSA strains at the same time. No such conclusions could be drawn based spa-typing and MLVA. Although PFGE seems to be suitable for molecular typing of LA-MRSA, WGM provides a much higher discriminatory power. Furthermore, whole genome mapping can provide a comparison with other maps within 2 days after the bacterial culture is received, making it suitable to investigate transmission events and outbreaks caused by LA-MRSA.     

Rapid Detection and Identification of Human Hookworm Infections through High Resolution Melting (HRM) Analysis

Background

Hookworm infections are still endemic in low and middle income tropical countries with greater impact on the socioeconomic and public health of the bottom billion of the world''s poorest people. In this study, a real-time polymerase chain reaction (PCR) coupled with high resolution melting-curve (HRM) analysis was evaluated for an accurate, rapid and sensitive tool for species identification focusing on the five human hookworm species.

Methods

Real-time PCR coupled with HRM analysis targeting the second internal transcribed spacer (ITS-2) of nuclear ribosomal DNA as the genetic marker was used to identify and distinguish hookworm species in human samples. Unique and distinct characteristics of HRM patterns were produced for each of the five hookworm species. The melting curves were characterized by peaks of 79.24±0.05°C and 83.00±0.04°C for Necator americanus, 79.12±0.10°C for Ancylostoma duodenale, 79.40±0.10°C for Ancylostoma ceylanicum, 79.63±0.05°C for Ancylostoma caninum and 79.70±0.14°C for Ancylostoma braziliense. An evaluation of the method''s sensitivity and specificity revealed that this assay was able to detect as low as 0.01 ng/µl hookworm DNA and amplification was only recorded for hookworm positive samples.

Conclusion

The HRM assay developed in this study is a rapid and straightforward method for the diagnosis, identification and discrimination of five human hookworms. This assay is simple compared to other probe-based genotyping methods as it does not require multiplexing, DNA sequencing or post-PCR processing. Therefore, this method offers a new alternative for rapid detection of human hookworm species.     

High Resolution Esophageal Manometry in Patients with Chagas Disease: A Cross-Sectional Evaluation

Introduction

Gastrointestinal involvement affects 30–40% of the patients with chronic Chagas disease. Esophageal symptoms appear once the structural damage is established. Little is known about the usefulness of high resolution manometry to early identification of esophageal involvement.

Method

We performed a cross-sectional study at the Vall d’Hebron University Hospital (Barcelona, Spain) between May 2011 and April 2012. Consecutive patients diagnosed with Chagas disease in the chronic phase were offered to participate. All patients underwent a structured questionnaire about digestive symptoms, a barium esophagogram (Rezende classification) and an esophageal high resolution manometry (HRM). A control group of patients with heartburn who underwent an esophageal HRM in our hospital was selected.

Results

62 out of 73 patients that were included in the study fulfilled the study protocol. The median age of the Chagas disease group (CG) was 37 (IQR 32–45) years, and 42 (67.7%) patients were female. Twenty-seven (43.5%) patients had esophageal symptoms, heartburn being the most frequent. Esophagogram was abnormal in 5 (8.77%). The esophageal HRM in the CG showed a pathological motility pattern in 14 patients (22.6%). All of them had minor disorders of the peristalsis (13 with ineffective esophageal motility and 1 with fragmented peristalsis). Hypotonic lower esophageal sphincter was found more frequently in the CG than in the control group (21% vs 3.3%; p<0.01). Upper esophageal sphincter was hypertonic in 22 (35.5%) and hypotonic in 1 patient. When comparing specific manometric parameters or patterns in the CG according to the presence of symptoms or esophagogram no statistically significant association were seen, except for distal latency.

Conclusion

The esophageal involvement measured by HRM in patients with chronic Chagas disease in our cohort is 22.6%. All the patients with esophageal alterations had minor disorders of the peristalsis. Symptoms and esophagogram results did not correlate with the HRM results.     

Evaluation of Viral Inactivation on Dry Surface by High Peak Power Microwave (HPPM) Exposure

Previous research has shown that virus infectivity can be dramatically reduced by radio frequency exposure in the gigahertz (GHz) frequency range. Given the worldwide SARS-CoV-2 pandemic, which has caused over 1 million deaths and has had a profound global economic impact, there is a need for a noninvasive technology that can reduce the transmission of virus among humans. RF is a potential wide area-of-effect viral decontamination technology that could be used in hospital rooms where patients are expelling virus, in grocery and convenience stores where local populations mix, and in first responder settings where rapid medical response spans many potentially infected locations within hours. In this study, we used bovine coronavirus (BCoV) as a surrogate of SARS-CoV-2 and exposed it to high peak power microwave (HPPM) pulses at four narrowband frequencies: 2.8, 5.6, 8.5, and 9.3 GHz. Exposures consisted of 2 µs pulses delivered at 500 Hz, with pulse counts varied by decades between 1 and 10,000. The peak field intensities (i.e. the instantaneous power density of each pulse) ranged between 0.6 and 6.5 MW/m², depending on the microwave frequency. The HPPM exposures were delivered to plastic coverslips containing BCoV dried on the surface. Hemagglutination (HA) and cytopathic effect analyses were performed 6 days after inoculation of host cells to assess viral infectivity. No change in viral infectivity was seen with increasing dose (pulse number) across the tested frequencies. Under all conditions tested, exposure did not reduce infectivity more than 1.0 log_10. For the conditions studied, high peak power pulsed RF exposures in the 2–10 GHz range appear ineffective as a virucidal approach for hard surface decontamination. © 2023 Bioelectromagnetics Society.     

斑马鱼二价体制备与多重带显带的方法学探讨

采用碱性低渗结合高氯仿一步显带技术获得了斑马鱼二价体高分辨多重G带,所出现的带纹丰富,反差明显。采用地高辛为标记的以限制性内切酶AfuⅠ介导的原位切口平移技术使斑马鱼二价体上呈现出类G带的多重带,获得了明暗反差强烈的带纹结果。通过比较多个不同分裂相的多条染色体,发现带纹的分布具明显特征性．并且特征一致,带纹数目基本吻合。首次从方法学上对斑马鱼二价体的制备过程及多重带显带技术进行了分析、探讨和总结,力求将该技术程序化、系统化,使其具有可重复性和可操作性,并对显带的可能机理进行了讨论。     

Resolution of steroid binding heterogeneity by Fourier-derived affinity spectrum analysis (FASA)

A new mathematical method of analyzing radioreceptor assay data is presented. When there are many binding classes with different affinities, the probability-density function B(p) is described by the equation B(p) = (integral negative infinity to infinity) q(k)f(p-k)dk, where q(k) is the affinity spectrum (density of a particular binding class as a function of affinity) and f(p-k) is a probability function (probability that dissociation constants will fall between k and p-k, where p is the free ligand concentration). This equation is solved for q(k) and evaluated explicitly by Fourier transformation, namely, q(w) = b(w)/f(w), where w is frequency. Since division by f(w) can amplify and high frequency noise present in the experimental data, a Gaussian smoothing function is introduced thus: qs(w) = q(w)e(-w/W0)2, where W0 is a constant. This produces an affinity spectrum defined as a plot of the number of binding sites, qs(k), versus their respective dissociation constants, k. Using a FORTRAN computer program, we verify this algorithm using simulated data. We also apply the procedure to resolve heterogeneous populations of estrogen binders in human endometrium using [3H]estradiol as ligand. Two estrogen binder classes are revealed with dissociation constants approximately 2.5 natural logarithmic units apart. We identify one high-affinity (Kd = 0.18 nM)-low density (70 pM [or 72 fmol/mg protein]) subpopulation and one low affinity (Kd = 2.5 nM)-high density (101 pM [or 102 fmol/mg protein]) subpopulation of estradiol binders. The management of experimental error, sampling limitations, and nonspecific binding are discussed. This method directly transforms experimental data into an easily interpretable representation without mathematical modeling or statistical procedures.     

Resolution of Clostridium stercorarium cellulase by fast protein liquid chromatography (FPLC)

Summary A fast and efficient separation procedure for the analysis of the cellulase components of the thermophilic anaerobe Clostridium stercorarium was developed. Culture respernatants were concentrated without loss of cellulase activity by tangential flow ultrafiltration. Resolution of the cellulase system was achieved by fast protein liquid chromatography (FPLC) on a Mono Q anion exchange column. Enzyme fractions were assayed for hydrolysis of Avicel, carboxymethylcellulose (CMC), -nitrophenyl--d-cellobioside, and p-nitrophenyl--d-glucoside. Two Avicelases, two -cellobiosidases, and one -glucosidase were identified and characterized by SDS-polyacrylamide electrophoresis and isoelectric focusing. On the basis of their activities towards CMC, Avicelase I was classified as endo--glucanase and Avicelase II as exo--glucanase. Efficient hydrolysis of microcrystalline cellulose was shown to result from the combined action of both Avicelases.     

Evaluation of High Resolution Melting for MTHFR C677T Genotyping in Congenital Heart Disease

Background

High resolution melting (HRM) is a simple, flexible and low-cost mutation screening technique. The methylenetetrahydrofolate reductase (MTHFR) gene encoding a critical enzyme, potentially affects susceptibility to some congenital defects like congenital heart disease (CHD). We evaluate the performance of HRM for genotyping of the MTHFR gene C677T locus in CHD cases and healthy controls of Chinese Han population.

Methods

A total of 315 blood samples from 147 CHD patients (male72, female 75) and 168 healthy controls (male 92, female 76) were enrolled in the study. HRM was utilized to genotype MTHFR C677T locus of all the samples. The results were compared to that of PCR-RFLP and Sanger sequencing. The association of the MTHFR C677T genotypes and the risk of CHD was analyzed using odds ratio with their 95% confidence interval (CIs) from unconditional logistic regression.

Results

All the samples were successfully genotyped by HRM within 1 hour and 30 minutes while at least 6 hours were needed for PCR-RFLP and sequencing. The genotypes of MTHFR C677T CC, CT, and TT were 9.52%, 49.66%, and 40.82% in CHD group but 29.17%, 50% and 20.83% in control group, which were identical using both methods of HRM and PCR-RFLP, demonstrating the sensitivity and specificity of HRM were all 100%.

Conclusion

MTHFR C677T is a potential risk factor for CHD in our local residents of Shandong province in China. HRM is a fast, sensitive, specific and reliable method for clinical application of genotyping.