Extensible benchmarking of methods that identify and quantify polyadenylation sites from RNA-seq data

The tremendous rate with which data is generated and analysis methods emerge makes it increasingly difficult to keep track of their domain of applicability, assumptions, limitations, and consequently, of the efficacy and precision with which they solve specific tasks. Therefore, there is an increasing need for benchmarks, and for the provision of infrastructure for continuous method evaluation. APAeval is an international community effort, organized by the RNA Society in 2021, to benchmark tools for the identification and quantification of the usage of alternative polyadenylation (APA) sites from short-read, bulk RNA-sequencing (RNA-seq) data. Here, we reviewed 17 tools and benchmarked eight on their ability to perform APA identification and quantification, using a comprehensive set of RNA-seq experiments comprising real, synthetic, and matched 3'-end sequencing data. To support continuous benchmarking, we have incorporated the results into the OpenEBench online platform, which allows for continuous extension of the set of methods, metrics, and challenges. We envisage that our analyses will assist researchers in selecting the appropriate tools for their studies, while the containers and reproducible workflows could easily be deployed and extended to evaluate new methods or data sets.

High-throughput data and modeling reveal insights into the mechanisms of cooperative DNA-binding by transcription factor proteins

Cooperative DNA-binding by transcription factor (TF) proteins is critical for eukaryotic gene regulation. In the human genome, many regulatory regions contain TF-binding sites in close proximity to each other, which can facilitate cooperative interactions. However, binding site proximity does not necessarily imply cooperative binding, as TFs can also bind independently to each of their neighboring target sites. Currently, the rules that drive cooperative TF binding are not well understood. In addition, it is oftentimes difficult to infer direct TF-TF cooperativity from existing DNA-binding data. Here, we show that in vitro binding assays using DNA libraries of a few thousand genomic sequences with putative cooperative TF-binding events can be used to develop accurate models of cooperativity and to gain insights into cooperative binding mechanisms. Using factors ETS1 and RUNX1 as our case study, we show that the distance and orientation between ETS1 sites are critical determinants of cooperative ETS1-ETS1 binding, while cooperative ETS1-RUNX1 interactions show more flexibility in distance and orientation and can be accurately predicted based on the affinity and sequence/shape features of the binding sites. The approach described here, combining custom experimental design with machine-learning modeling, can be easily applied to study the cooperative DNA-binding patterns of any TFs.

Expression of FOXO3 in the skin follicles of goose embryos during embryonic development

1. The Forkhead box O3 (FOXO3) transcription factor is a crucial regulator in controlling cell metabolism, proliferation, apoptosis, migration and response to oxidative stress. However, FOXO3 has not previously been studied much in the embryonic skin follicles of geese.2. This study used Zhedong white geese (Anser cygnoides), Jilin white geese (Anser cygnoides) and Hungarian white geese (Anser anser). The feather follicle structure in the dorsal skin during embryonic stages was examined with haematoxylin and eosin (HE) and Pollak staining. The FOXO3 protein content in the embryonic dorsal skin from feather follicles was detected using western blotting and quantitative real-time PCR.3. The mRNA expression level of FOXO3 in the dorsal skin of Jilin white geese was highly expressed on embryonic day 23 (E23; P < 0.01), while mRNA expression of FOXO3 was highly expressed in the feather follicle of Hungarian white geese at E28 (P < 0.01). The expression of FOXO3 protein mainly concentrated in the early embryonic phase among these goose breeds (P < 0.05). This suggested that FOXO3 plays a crucial role in the development and growth of embryonic dorsal skin of feather follicles. The location of the FOXO3 protein was determined using the IHC technique, which further verified the effect of FOXO3 in the dorsal skin for feather follicles during embryogenesis.4. The study demonstrated the differential expression and localisation of the FOXO3 gene among different goose species. It was speculated that the gene could potentially improve goose feather follicle development and feather-related traits and provide a basis for further understanding of FOXO3 function in the dorsal tissue of goose embryos.

Extensible benchmarking of methods that identify and quantify polyadenylation sites from RNA-seq data

The tremendous rate with which data is generated and analysis methods emerge makes it increasingly difficult to keep track of their domain of applicability, assumptions, and limitations and consequently, of the efficacy and precision with which they solve specific tasks. Therefore, there is an increasing need for benchmarks, and for the provision of infrastructure for continuous method evaluation. APAeval is an international community effort, organized by the RNA Society in 2021, to benchmark tools for the identification and quantification of the usage of alternative polyadenylation (APA) sites from short-read, bulk RNA-sequencing (RNA-seq) data. Here, we reviewed 17 tools and benchmarked eight on their ability to perform APA identification and quantification, using a comprehensive set of RNA-seq experiments comprising real, synthetic, and matched 3'-end sequencing data. To support continuous benchmarking, we have incorporated the results into the OpenEBench online platform, which allows for seamless extension of the set of methods, metrics, and challenges. We envisage that our analyses will assist researchers in selecting the appropriate tools for their studies. Furthermore, the containers and reproducible workflows generated in the course of this project can be seamlessly deployed and extended in the future to evaluate new methods or datasets.

GENESIS: Gene-Specific Machine Learning Models for Variants of Uncertain Significance Found in Catecholaminergic Polymorphic Ventricular Tachycardia and Long QT Syndrome-Associated Genes

BACKGROUND

Cardiac channelopathies such as catecholaminergic polymorphic tachycardia and long QT syndrome predispose patients to fatal arrhythmias and sudden cardiac death. As genetic testing has become common in clinical practice, variants of uncertain significance (VUS) in genes associated with catecholaminergic polymorphic ventricular tachycardia and long QT syndrome are frequently found. The objective of this study was to predict pathogenicity of catecholaminergic polymorphic ventricular tachycardia-associated RYR2 VUS and long QT syndrome-associated VUS in KCNQ1, KCNH2, and SCN5A by developing gene-specific machine learning models and assessing them using cross-validation, cellular electrophysiological data, and clinical correlation.

METHODS

The GENe-specific EnSemble grId Search framework was developed to identify high-performing machine learning models for RYR2, KCNQ1, KCNH2, and SCN5A using variant- and protein-specific inputs. Final models were applied to datasets of VUS identified from ClinVar and exome sequencing. Whole cell patch clamp and clinical correlation of selected VUS was performed.

RESULTS

The GENe-specific EnSemble grId Search models outperformed alternative methods, with area under the receiver operating characteristics up to 0.87, average precisions up to 0.83, and calibration slopes as close to 1.0 (perfect) as 1.04. Blinded voltage-clamp analysis of HEK293T cells expressing 2 predicted pathogenic variants in KCNQ1 each revealed an ≈80% reduction of peak Kv7.1 current compared with WT. Normal Kv7.1 function was observed in KCNQ1-V241I HEK cells as predicted. Though predicted benign, loss of Kv7.1 function was observed for KCNQ1-V106D HEK cells. Clinical correlation of 9/10 variants supported model predictions.

CONCLUSIONS

Gene-specific machine learning models may have a role in post-genetic testing diagnostic analyses by providing high performance prediction of variant pathogenicity.

Machine Learning Algorithms to Predict Mortality and Allocate Palliative Care for Older Patients With Hip Fracture

OBJECTIVES

To evaluate a machine learning model designed to predict mortality for Medicare beneficiaries aged >65 years treated for hip fracture in Inpatient Rehabilitation Facilities (IRFs).

DESIGN

Retrospective design/cohort analysis of Centers for Medicare & Medicaid Services Inpatient Rehabilitation Facility-Patient Assessment Instrument data.

SETTING AND PARTICIPANTS

A total of 17,140 persons admitted to Medicare-certified IRFs in 2015 following hospitalization for hip fracture.

MEASURES

Patient characteristics include sociodemographic (age, gender, race, and social support) and clinical factors (functional status at admission, chronic conditions) and IRF length of stay. Outcomes were 30-day and 1-year all-cause mortality. We trained and evaluated 2 classification models, logistic regression and a multilayer perceptron (MLP), to predict the probability of 30-day and 1-year mortality and evaluated the calibration, discrimination, and precision of the models.

RESULTS

For 30-day mortality, MLP performed well [acc = 0.74, area under the receiver operating characteristic curve (AUROC) = 0.76, avg prec = 0.10, slope = 1.14] as did logistic regression (acc = 0.78, AUROC = 0.76, avg prec = 0.09, slope = 1.20). For 1-year mortality, the performances were similar for both MLP (acc = 0.68, AUROC = 0.75, avg prec = 0.32, slope = 0.96) and logistic regression (acc = 0.68, AUROC = 0.75, avg prec = 0.32, slope = 0.95).

CONCLUSION AND IMPLICATIONS

A scoring system based on logistic regression may be more feasible to run in current electronic medical records. But MLP models may reduce cognitive burden and increase ability to calibrate to local data, yielding clinical specificity in mortality prediction so that palliative care resources may be allocated more effectively.

Comparison of pharmacokinetics of tilmicosin in healthy pigs and pigs experimentally infected with Actinobacillus pleuropneumoniae

Aim: To compare the pharmacokinetic profiles of tilmicosin, administered orally at a single dose of 20 mg/kg bodyweight, in healthy pigs and in pigs experimentally infected with Actinobacillus pleuropneumoniae. Methods: Twelve healthy crossbred pigs, aged approximately 8 weeks, were randomly assigned to uninfected and infected groups, with six pigs per group. Pigs in the infected group were inoculated intranasally with a bacterial suspension of A. pleuropneumoniae containing approximately 10⁸ cfu. Each pig received a single oral dose of 20 mg/kg bodyweight of tilmicosin, given 3-4 hours after inoculation in infected pigs. Blood samples were collected before drug administration and up to 48 hours after tilmicosin administration. Concentrations of tilmicosin in plasma samples were determined by HPLC. Throughout the experimental period pigs were observed for signs of inappetence and clinical abnormalities. After sampling was complete pigs were subject to euthanasia and samples collected for gross and histopathology as well as microbiology. Results: Infected pigs showed signs of bradykinesia, nasal discharge dyspnoea, and coughing 1 hours after inoculation and A. pleuropneumoniae was cultured from the lungs of all infected pigs postmortem. Comparing pharmacokinetic parameters in uninfected and infected pigs, the maximum plasma concentration of tilmicosin was higher in uninfected pigs (1.17 (SD 0.17) vs. 0.96 (SD 0.17) µg/mL), the time to reach maximum concentration was shorter (1.53 (SD 0.23) vs. 2.40 (SD 0.37) hours), and the half-life of the absorption phase and half-life of the elimination phase were both shorter (0.66 (SD 0.08) vs. 1.00 (SD 0.27) hours) and (12.93 (SD 0.96) vs. 16.53 (SD 0.55) hours), respectively. The apparent volume of distribution was smaller in uninfected than infected pigs (1.91 (SD 0.22) vs. 2.16 (SD 0.21) L/kg). The relative bioavailability of tilmicosin in infected relative to uninfected pigs was 108.6 (SD 9.71)%. Conclusions and clinical relevance: The results of this study indicate that A. pleuropneumoniae infection significantly changed certain pharmacokinetic parameters of tilmicosin in pigs. In infected pigs tilmicosin exhibited a longer drug persistence and a better extent of absorption. These results indicate that it is necessary to monitor and adjust the dose of tilmicosin administration during the presence of pleuropneumonia. It is expected that this can optimise clinical efficacy and help avoid the development of resistance.

TGF-beta receptor II in epithelia versus mesenchyme plays distinct roles in the developing lung

Transforming growth factor (TGF)-beta signalling plays important roles in regulating lung development. However, the specific regulatory functions of TGF-beta signalling in developing lung epithelial versus mesenchymal cells are still unknown. By immunostaining, the expression pattern of the TGF-beta type II receptor (TbetaRII) was first determined in the developing mouse lung. The functions of TbetaRII in developing lung were then determined by conditionally knocking out TbetaRII in the lung epithelium of floxed-TbetaRII/surfactant protein C-reverse tetracycline transactivator/TetO-Cre mice versus mesenchyme of floxed-TbetaRII/Dermo1-Cre mice. TbetaRII was expressed only in distal airway epithelium at early gestation (embryonic day (E)11.5), but in both airway epithelium and mesenchyme from mid-gestation (E14.5) to post-natal day 14. Abrogation of TbetaRII in mouse lung epithelium resulted in retardation of post-natal lung alveolarisation, with markedly decreased type I alveolar epithelial cells, while no abnormality in prenatal lung development was observed. In contrast, blockade of TbetaRII in mesoderm-derived tissues, including lung mesenchyme, resulted in mildly abnormal lung branching and reduced cell proliferation after mid-gestation, accompanied by multiple defects in other organs, including diaphragmatic hernia. The primary lung branching defect was verified in embryonic lung explant culture. The novel findings of the present study suggest that transforming growth factor-beta type II receptor-mediated transforming growth factor-beta signalling plays distinct roles in lung epithelium versus mesenchyme to differentially control specific stages of lung development.

Reproduction and cytogenetic characterization of interspecific hybrids derived from Cucumis hystrix Chakr. x Cucumis sativus L

Interspecific hybrids between Cucumis hystrix Chakr. (2n = 2 x = 24) and Cucumis sativus L. (2n = 2 x = 14) were produced by means of F(1) (2n = 19) embryo rescue and subsequent chromosome doubling. The hybridity was confirmed by genomic in situ hybridization (GISH) and chromosome analysis. The amphidiploid (2n = 38) was self-pollinated and backcrossed to cucumber resulting in lines with improved crossability to C. sativus. Examination of shape, stainability, and germination rate of pollen grains and yield as a function of mature fruit set per ten pollinated flowers indicated a tendency for increased fertility in BC(1)S(1) progeny when compared to F(1) and amphidiploid offspring. Cytogenetic characterization of F(1) and amphidiploid progeny was performed. Generally normal meioses produced viable pollen grains, and fertilization resulted in partial fertility restoration in amphidiploid progeny. Chromosome anomalies such as "frying-pan trivalent", chromosome lagging and spindle mis-orientation were also observed. In most of the PMCs of the F(1) diploid hybrid progeny, 19 univalents were observed at diakinesis and MI. In the amphidiploid, more than 90% of the configurations at MI consisted of the predicted 19 bivalents and less than 5% contained multivalents [trivalents (2.3%) + quadrivalents (0.3%)], suggesting the presence of preferential pairing, and a distinctive parental genome as well. The chiasmata observed between homoeologous chromosomes further demonstrated the introgression of the C. hystrix genome into that of C. sativus.

Effect of re-feeding after starvation on biomechanical properties in rat small intestine

Luminal nutrients are essential for maintaining the structural and functional integrity of the gut. Starvation induces pronounced structural and biomechanical remodelling in the rat small intestine. The present work was done to study the recovery process after resumption of food intake. Twenty-five Wistar rats were allocated to five groups. Four groups fasted for 7 days but had free access to water. One of these groups served as fasted controls and was killed at the end of the fast. The other three groups were re-fed for 2, 4 and 7 days before they were euthanised. The fifth group had free access to food during the whole study (fed controls). The intestinal no-load state, zero-stress state and the stress-strain relationship during distension were studied. The intestinal segments were cut transversely into a series of short ring-shaped segments to obtain the no-load state. Each ring was cut in the radial direction to obtain the zero-stress state. The rats regained the lost body weight (22%) by the 7th day of re-feeding. The lost duodenal mass (40%) and jejunal mass (25%) were regained by the 2nd day whereas the lost mass from ileum (18%) was regained by the 4th day. The fasting-induced morphometric changes were normalised by re-feeding on the 2nd day in the duodenum and jejunum, and on the 4th day in the ileum. The longitudinal stress-strain curves shifted to the right after fasting and shifted back within two days following re-feeding (P<0.05). The circumferential stress-strain curves in the fasted or re-fed rats changed in a similar though less pronounced way. Normal values were reached within 4-7 days for the circumferential direction. In conclusion, fasting-induced biomechanical and structural remodelling were normalised by re-feeding in a time- and location-dependent way.

Tetramethylpyrazine inhibits phytohemagglutinin-induced upregulation of ICAM-1 and LFA-1 mediated leukocyte adhesion

The aim of this work was to study the effects of tetramethylpyrazine (TMP) on the interaction between lymphocyte function-associated antigen-1 (LFA-1) and intercellular adhesive molecule-1 (ICAM-1) by micropipette technique. A pair of cells, i.e., a human lymphocyte or a S KW-3 cell (human T cell leukemia), LFA-1 was expressed on which cellular surfaces, and a RBC coupled with ICAM-1, were the carriers for LFA-1 and ICAM-1. The adhesion probabilities of this pair of cells were mediated by specific interactions between ICAM-1 and LFA-1. Phytohemagglutinin (PHA) stimulation resulted in the significant increase in the adhesion probability compared to the resting lymphocyte. TMP treatment can inhibit such increase and even make the adhesion probability lower than the resting state. While the LFA-1 expression has not changed significantly with PHA stimulation or with TMP treatment, which indicated that TMP inhibiting effects was realized by a possible conformation change.

[A simulating study of biophysical features along meridians on a gel model]

A physical model was used to study the mechanism of specific biophysical features along the classic acupuncture meridian lines. A sol channel within a gel bed was made by a resistance string heating during electrification. A saline channel was produced by withdrawing some fibers in the gel bed and injecting saline into the gaps. A hydraulic resistance instrument composed by two pressure transducers was used to measure the hydraulic resistance across the two kinds of channels. The impedance on both channels was measured by a four-electrode impedance instrument with 5 KHz constant current. A vibration generator was put on one set of the channel to produce about 50 Hz sound waves. The signal was detected by a crystal pickup on the other set of the channel to examine the transmission of the wave along the two kinds of channels. The results showed that the low hydraulic resistance appeared on saline channel while no such feature on sol channel. Both channels showed low impedance while saline channel had more marked low impedance than control area. There was a better transmission of sound wave along saline channel while a bad transmission along the sol channel. The results suggest that the specific biophysical feature along meridians may be caused by a continuous rich distribution of interstitial fluid which mainly contains salt, water and protein.

[Expression property of adhesive molecule ICAM-1 on vitro-cultured pulmonary microvascular endothelial cells under the stimuli of asthmatic serum]

It has been recognized only in the past 15 years that the major pathological mechanism of asthma is inflammation, which has a hallmark of focal leukocyte extravasation. The different recruitment behaviors of inflammatory cells depend on the expression of specific adhesive molecules on both leukocytes and endothelial cells (EC). Intercellular cellular adhesion molecule-1(ICAM-1) plays a major role. In the previous detailed in-vivo study of asthmatic models, we have proved the significant pathological increase of both the leukocyte-endothelium adhesion phenomenon and the ICAM-1 expression in the tissues of asthmatic lung. It may be due to an ICAM-1 accumulation on the microvascular endothelial cells and thus an enhancement of adhesion force during the course of disease. In this study, endothelial cells were obtained from rats by mechanical isolation of lung tissues and in vitro culture on glass. Confluent endothelial cells were incubated with serum collected from rat blood of normal and asthmatic models and were used for in vitro study of endothelial cell adhesion. The effect of pathological serum stimulation was examined on the expression of ICAM-1 of the pulmonary microvascular endothelial cells (PMEC). The expression of ICAM-1 on PMEC was measured by indirect immuno-fluorescence with flow cytometry. We found that the surface expression of ICAM-1 was obviously increased on serum-incubated EC as compared with that on the culture solution-incubated one, and that asthmatic serum increased the expression of ICAM-1 on EC to a peak in 4 hours and then decreased it rapidly, the expression level remained the same in the whole course when EC was treated with culture solution or normal serum.

[Epidemiological effects of live attenuated hepatitis A vaccine (H(2)-strain): results of A 10-year observation]

OBJECTIVE

To assess the long-term epidemiological effects after a mass vaccination program, using live attenuated hepatitis A vaccine (H(2)-strain).

METHODS

Shengsi county and Jiaojiang city in Zhejiang province were chosen where high incidence rate of hepatitis A was observed. Mass vaccination program of H(2)-strain vaccine was carried out on 1 - 15 year olds. Cohort studies included two groups were carried out in Shengsi. Cases reported program on hepatitis A was under the national standard on clinical diagnosis and partly through laboratory monitor of anti-HAV IgM and IgG, ELISA and Abbott EIA. Population size was estimated by the yearly reports of census bureau of the county and the city. Serum tests including neutralization test, immune-recall responses, and anti-HAV IgG were performed 10 years after the initial immunization.

RESULTS

The morbidity of hepatitis A was significantly different between vaccinated groups and non-vaccinated groups (P < 0.01) in the cohort study. The protective efficacy in the site was 100 percent. There was a significantly negative correlation of regression between vaccine coverage and hepatitis A morbidity. In both sites, hepatitis A incidence rate showed decrease of 94.5% and 90.3% in whole population, with 96.9% and 97.9% in 1 - 15 year olds respectively. Neutralization test showed that 63.8% of the serum negative to ELISA after vaccination could still neutralize certain HAV. Immune-recall response after the booster was seen in vaccine group with 80.2% positive rate of anti HAV-IgG, 10 years after immunization among vaccinees in both sites. Not a single hepatitis A case was identified.

CONCLUSION

Live attenuated hepatitis A vaccine seemed to have obviously long-term epidemiological effects.

Biomechanical and morphometric properties of the arterial wall referenced to the zero-stress state in experimental diabetes

Morphometric and passive biomechanical properties were studied in isolated segments of the thoracic and abdominal aorta, left common carotid artery, left femoral artery and the left pulmonary artery in 20 non-diabetic and 28 streptozotocin (STZ)-induced diabetic rats. The diabetic and non-diabetic rats were divided into groups living 1, 4, 8, and 12 weeks after the induction of diabetes (n = 7 for each diabetic group) or sham injection (n = 5 for each group). The mechanical test was performed as a distension experiment where the proximal end of the arterial segment was connected via a tube to the container used for applying pressures to the segment and the distal end was left free. The vessel diameter and length were obtained from digitized images of the arterial segments at pre-selected pressures and at no-load and zero-stress states. Circumferential and longitudinal stresses (force per area) and strains (deformation) were computed from the length, diameter and pressure data and from the zero-stress state data. The zero-stress state was obtained by cutting vessel rings radially causing the rings to open up into a sector. Diabetes was associated with pronounced morphometric changes, e.g., wall thickness. With respect to the biomechanical data, the opening angle increased and reached a plateau in 4 weeks after which it decreased again (p < 0.05). The opening angle was smallest in the thoracic aorta and largest in the pulmonary artery. Furthermore, it was found that the circumferential stiffness of the arteries studied increased with the duration of diabetes. In the longitudinal direction significant differences were found 8 weeks after injection of STZ in all arteries except the pulmonary artery. In the 12 weeks group, the femoral artery was stiffest in the circumferential direction whereas the thoracic aorta was stiffest in the longitudinal direction. The accumulated serum glucose level correlated with the arterial wall thickness and elastic modulus (correlation coefficient between 0.56 and 0.81).

Absolute and convective instabilities of the natural convection in a vertical heated slot

The spatiotemporal instability of a natural convection flow in vertical heated slot is studied theoretically. The two unstable modes, secondary cell and traveling wave, are illustrated to be absolute and convective instabilities, respectively. Using a model to simulate the temperature gradient in the center of the slot, we propose an interpretation of the mechanism controlling the reverse transition of flow patterns, and explain the temperature fluctuation observed after the reverse transition in terms of the traveling wave mode.

[Surgical resection of giant hemangioma]

OBJECTIVE

Through the operative experiences in 45 cases of giant hemangioma, it is elucidated that the operative procedure for hemangioma is an effective, radical method of treatment.

METHODS

1. Preoperative DSA can establish the diagnosis, delineate the range of lesion and facilitate the design of operation. 2. "Dissection over the false capsule" is applied in the operation. 3. The operative wound, is repaired with a plastic procedure.

RESULTS

Of the 45 patients primary cure was obtained in 27, and secondary cure in 13 with effective rate of 89 percent. The followed-up was as long as 8 years with excellent results.

CONCLUSIONS

The establishment of operative scheme is chiefly based on preoperative DSA, and the success is fundamentally determined by complete dissection over the so-called "false capsule" around the tumour during operation. This procedure can totally remove the tumour, eliminate recurrence and fulfil the purpose of radical resection, which is worthy of wide application.

[Separation of thoracopagus conjoined twins]

OBJECTIVE

To sam up the experience in diagnosis and separation of a thoracopagus conjoined twins.

METHODS

Thoracopagus twin boys were admitted for evaluating possible separation and repair at age of 21 days. X-rays, CT, MRI, and ultrasound scan of torso showed separate and normal gastrointestinal and biliary tracts, little shared vasculature, but shared pericardium, diaphragm and liver parenchyma. The chest junctions were at the sternums and the most inferior two pairs of the ribs. One twin (twin A) had a protruding heart with VSD and ASD.

RESULTS

The infants were separated successfully at age of 45 days. The chest defect of twin A was closed with aid of a polyester pericardial patch graft and a silicon supporter. Managing anesthesia met some difficulty in understanding of the anatomical and physiological consequences of the complex anomaly. They are had brain edema and multiple system organ failures after separation, and were cured under intensive care. They are alive and well 6 months after surgery.

CONCLUSIONS

Careful preoperative evaluation proper anesthesia and surgical technique, and postoperative care are essential to the successful separation of the conjoined twins.

Urinary N-acetyl-beta-D-glucosaminidase isoenzymes as biomarker of renal dysfunction caused by cadmium in a general population

N-Acetyl-beta-D-glucosaminidase (NAG) and its isoenzymes in urine have been studied in a population group residing in a polluted area in China. The area studied was contaminated by industrial wastewater from a nearby smelter that discharged cadmium-polluted wastewater into a river used for the irrigation of rice fields. Cadmium concentrations in rice were 3.70, 0.51, and 0.07 mg/kg for the highly and moderately polluted areas and the control area, respectively. Cadmium concentrations in urine exceeded 5 microgram/liter in the majority of subjects in the most highly polluted area. There was a marked dose-dependent increase in NAG and NAG B content of urine related both to urinary cadmium and to the calculated cadmium uptake. It is concluded that urinary NAG and its isoenzymes could serve as a sensitive biomarker of renal dysfunction in cadmium-exposed populations. The mechanisms underlying the increase in NAG and its isoenzymes after cadmium exposure need to be studied further.

[Study on comprehensive assessment in selection of special work personnel]

A comprehensive assessment method combining fuzzy set theory with traditional approaches is introduced. Method of index assessment and comprehensive assessment along with a fuzzy assessment model are presented. As an example, three fuzzy algorithms are used to assess 6 candidates. Calculated results show that the combination of fuzzy logic and experience of experts is feasible and can deal with unprecise information more effectively as well as the aggregation of fuzzy information and precise data. The new method described in this paper is accurate and the speed of decision-making is much improved as compared with the conventional approaches.

Biological monitoring of cadmium exposure and renal effects in a population group residing in a polluted area in China

In an area of China, not previously studied in detail concerning cadmium pollution and possible adverse effects on the kidney of exposed populations, concentrations of cadmium in urine as an indicator of renal accumulation of cadmium was studied and related to indicators of renal dysfunction in order to examine if a relationship could be documented. Cadmium concentrations in urine were analysed by graphite furnace atomic absorption spectrometry and urinary beta-2 microglobulin (UBM) and albumin (UALB) were measured as indicators of renal dysfunction, Rice samples and urine samples were obtained from three areas in Zhejiang province, China, representing a highly exposed area, a medium exposed area and a control area, respectively. Cadmium concentrations in rice were 3.70, 0.51 and 0.072 mg/kg for the heavily, medium polluted areas and the control area, respectively. Cadmium concentrations in urine (geometric means) were 10.7, 1.62 and 0.40 micrograms/l in the high, medium and control areas respectively. There was a clear increase in UBM and UALB in the heavily exposed group in comparison to the control group and a slight increase in the medium exposed group. There was a statistically significant dose-response relationship between cadmium in urine and beta 2-microglobulin excretion in urine, which is similar to what has previously been reported in other countries. The findings constitute the first report concerning a dose-response relationship in this population group in Zhejiang province in China.

Alteration of left ventricular diastolic function during coronary angioplasty-induced ischemia: a color M-mode Doppler study

OBJECTIVES

The aim of this study was to assess the effects of ischemia on diastolic function by analyzing flow propagation velocity with color M-mode Doppler echocardigraphy.

BACKGROUND

Color M-mode Doppler echocardiography has been proposed as a method of assessing left ventricular filling.

METHODS

Color M-mode Doppler echocardiography and measurement of hemodynamic data were performed simultaneously at baseline and during angioplasty-induced ischemia. Tau was compared with flow propagation velocity. Late diastolic indexes, left ventricular pressure and flow cessation time were also investigated.

RESULTS

During ischemia, left ventricular relaxation rate (tau) increased, whereas flow propagation velocity decreased, from (mean +/- SD) 46.8 +/- 10 ms to 72.6 +/- 18.3 ms and from 59.8 +/- 15.8 cm/s to 30 +/- 8 cm/s, respectively (all p < 0.0001). The maximal slowing of flow propagation velocity was observed 20 to 30 s after the beginning of the inflation, coexisting with a notch on the ascending limb of the negative rate of rise of the left ventricular pressure (dP/dt) curve. Flow propagation velocity was correlated with tau both at baseline (r = 0.53, p < 0.05) and during inflation (r = 0.53, p < 0.03). Left ventricular end-diastolic pressure increased during ischemia from 13.5 +/- 8 mm Hg at baseline to 27.5 +/- 7 mm Hg, while a premature cessation of the entering flow occurred -13.8 +/- 23 ms before the next Q wave onset, compared with 4.5 +/- 19.6 ms after the Q wave onset at baseline (all p < 0.0001).

CONCLUSIONS

The analysis of flow propagation velocity showed that early filling is highly dependent on left ventricular relaxation rate, particularly through the phenomenon of asynchrony. During ischemia, the premature cessation of late filling is associated with increased diastolic pressures.

[A study on the newly designed platysma myocutaneous flap and its clinical applications]

From 1978 to 1991, the platysma myocutaneous flap of different designs was used to treat 69 patients with tumor extirpation defects of temporomandibular ankylosis. The conventional platysma myocutaneous flap was used to repair buccal defects. The combined platysma and sternocleidomastoid myocutaneous flap was used to reconstruct the tongue and the floor of the mouth. The innovated platysma myocutaneous flap, i.e. folded platysma myocutaneous flap was used to reconstruct the temporomandibular joint capsule for true ankylosis. All the procedure was completed in one stage and the operative results were satisfactory.