Body size and prostate cancer: a population-based case-control study in China

We conducted a population-based case-control study in China to investigate whether body size plays a role in prostate cancer etiology and whether it can explain the rapid increase in prostate cancer incidence rates in China. A total of 238 cases newly diagnosed with primary prostate cancer in Shanghai, China, during 1993-1995 were included in the study. Four hundred and seventy-one healthy control subjects were randomly selected from among residents of Shanghai and frequency-matched to cases on the basis of age. In-person interviews were conducted to elicit information on height, weight history, and other lifestyle factors. Waist and hip circumferences were measured at interview. Odds ratios (ORs) were used to measure the association between prostate cancer and anthropometric variables including height, weight, body mass index (BMI), waist, hip, and right upper arm circumferences, and waist-to-hip ratio (WHR; an indicator of abdominal adiposity). High levels of WHR were related to an excess risk, with men in the highest quartile (WHR > 0.92) having an almost 3-fold risk (OR, 2.71; 95% CI = 1.66-4.41; Ptrend = 0.0001) compared with men in the lowest quartile (WHR < 0.86). In contrast, men in the highest quartile of hip circumference (>97.4 cm) had a reduced risk (OR, 0.46; 95% CI = 0.29-0.74; Ptrend = 0.0002) relative to men in the lowest quartile (<86 cm). No association was found for height, usual adult weight, or preadult and usual adult BMI. Our results suggest that even in a very lean population (average BMI = 21.9), abdominal adiposity may be associated with an increased risk of clinical prostate cancer, pointing to a role of hormones in prostate cancer etiology. Additional research is needed to confirm these findings in prospective studies, especially in Western populations where abdominal obesity is much more common, and to clarify the underlying hormonal mechanisms involved.

Buprenorphine given after surgery does not alter renal ischemia/reperfusion injury

BACKGROUND AND PURPOSE

Potential drugs for human acute renal failure are often tested in an animal model of renal ischemia/reperfusion injury. Analgesics are often not given after surgery because of concerns that they would alter renal function. Therefore, we tested whether postoperative analgesia would alter animal health or affect the degree of renal injury.

METHODS

Mice were subjected to either 32 or 37 minutes of renal ischemia, given two or six doses of buprenorphine or vehicle at 12-hour intervals, and followed for 72 hours. In some animals, we measured body temperature and physical activity by use of telemetry.

RESULTS

Animals treated with buprenorphine recovered more rapidly from surgery based on postoperative activity, and had a small but not significant tendency for faster restoration of normal body temperature. Animals treated with buprenorphine had less weight loss after 37 minutes of ischemia. Buprenorphine given after surgery did not influence the degree of renal injury after ischemia/reperfusion.

CONCLUSIONS

Buprenorphine should be given after renal ischemia-reperfusion surgery because administration of the proper analgesic improved animal health without interfering with the renal ischemia/reperfusion model. Analgesic treatment at the time of the operation and 12 hours after was sufficient. Buprenorphine may reduce the post-surgical stress response, and thus potentially improve the specificity of testing for drugs that reduce or treat renal injury.

Allergen-induced airway hyperreactivity is diminished in CD81-deficient mice

We demonstrated previously that CD81(-/-) mice have an impaired Th2 response. To determine whether this impairment affected allergen-induced airway hyperreactivity (AHR), CD81(-/-) BALB/c mice and CD81(+/+) littermates were sensitized i.p. and challenged intranasally with OVA. Although wild type developed severe AHR, CD81(-/-) mice showed normal airway reactivity and reduced airway inflammation. Nevertheless, OVA-specific T cell proliferation was similar in both groups of mice. Analysis of cytokines secreted by the responding CD81(-/-) T cells, particularly those derived from peribronchial draining lymph nodes, revealed a dramatic reduction in IL-4, IL-5, and IL-13 synthesis. The decrease in cytokine production was not due to an intrinsic T cell deficiency because naive CD81(-/-) T cells responded to polyclonal Th1 and Th2 stimulation with normal proliferation and cytokine production. Moreover, there was an increase in T cells and a decrease in B cells in peribronchial lymph nodes and in spleens of immunized CD81(-/-) mice compared with wild-type animals. Interestingly, OVA-specific Ig levels, including IgE, were similar in CD81(-/-) and CD81(+/+) mice. Thus, CD81 plays a role in the development of AHR not by influencing Ag-specific IgE production but by regulating local cytokine production.

Synthesis and crystal structure of an octamer RNA r(guguuuac)/r(guaggcac) with G.G/U.U tandem wobble base pairs: comparison with other tandem G.U pairs

We have determined the crystal structure of the RNA octamer duplex r(guguuuac)/r(guaggcac) with a tandem wobble pair, G.G/U.U (motif III), to compare it with U.G/G.U (motif I) and G.U/U.G (motif II) and to better understand their relative stabilities. The crystal belongs to the rhombohedral space group R3. The hexagonal unit cell dimensions are a = b = 41.92 A, c = 56.41 A, and gamma = 120 degrees, with one duplex in the asymmetric unit. The structure was solved by the molecular replacement method at 1.9 A resolution and refined to a final R: factor of 19.9% and R(free) of 23.3% for 2862 reflections in the resolution range 10.0-1.9 A with F >/= 2sigma(F). The final model contains 335 atoms for the RNA duplex and 30 water molecules. The A-RNA stacks in the familiar head-to-tail fashion forming a pseudo-continuous helix. The uridine bases of the tandem U.G pairs have slipped towards the minor groove relative to the guanine bases and the uridine O2 atoms form bifurcated hydrogen bonds with the N1 and N2 of guanines. The N2 of guanine and O2 of uridine do not bridge the 'locked' water molecule in the minor groove, as in motifs I and II, but are bridged by water molecules in the major groove. A comparison of base stacking stabilities of motif III with motifs I and II confirms the result of thermodynamic studies, motif I > motif III > motif II.

Validation of a Monte Carlo dose calculation tool for radiotherapy treatment planning

A new EGS4/PRESTA Monte Carlo user code, MCDOSE, has been developed as a routine dose calculation tool for radiotherapy treatment planning. It is suitable for both conventional and intensity modulated radiation therapy. Two important features of MCDOSE are the inclusion of beam modifiers in the patient simulation and the implementation of several variance reduction techniques. Before this tool can be used reliably for clinical dose calculation, it must be properly validated. The validation for beam modifiers has been performed by comparing the dose distributions calculated by MCDOSE and the well-benchmarked EGS4 user codes BEAM and DOSXYZ. Various beam modifiers were simulated. Good agreement in the dose distributions was observed. The differences in electron cutout factors between the results of MCDOSE and measurements were within 2%. The accuracy of MCDOSE with various variance reduction techniques was tested by comparing the dose distributions in different inhomogeneous phantoms with those calculated by DOSXYZ without variance reduction. The agreement was within 1.0%. Our results demonstrate that MCDOSE is accurate and efficient for routine dose calculation in radiotherapy treatment planning, with or without beam modifiers.

[Evaluation of red cell mean corpuscular volume and simple tube red cell osmotic fragility quantitative test in detection of thalassemia]

OBJECTIVE

To evaluate and compare the detection efficiency of red cell mean corpuscular volume(MCV) test against simple tube red cell osmotic fragility quantitative test(STROFQT) in diagnosis of thalassemia.

METHODS

1978 subjects (989 couples) were detected by both MCV test and STROFQT, 158 samples from subjects were tested by alpha,beta-thalassemia DNA polymerase chain reaction(PCR) and serum ferritin test.

RESULTS

The positive rate (9.0%), sensitivity (98.9%) of MCV test were higher than those of STROFQT (8.1%, 88.6%) (P < 0.05). The specificity of MCV test showed no statistic significance compared with that of STROFQT (P > 0.05).

CONCLUSION

Both MCV test and STROFQT served as helpful approaches in detection of thalassemia, MCV test shows better diagnostic efficiency for screening than STROFQT.

Probing trace phenols based on mediator-free alumina sol--gel-derived tyrosinase biosensor

A novel tyrosinase biosensor has been developed for the subnanomolar detection of phenols, based on the immobilization of tyrosinase in a positively charged Al2O3 sol-gel membrane on a glassy carbon electrode. It has been found that Al2O3 sol-gel is perfectly beneficial to the immobilization of tyrosinase, because it not only possesses the general advantages of sol-gel but it also is an effective promoter of the biosensor. The large microscopic surface area, porous morphology, and hydrophilic property of the sol-gel matrix result in high enzyme loading, and the enzyme entrapped in this matrix retains its activity to a large extent. The Al2O3 sol-gel-containing surface also displays an intrinsic electrocatalytic o-quinone response and, hence, offers a high-sensitivity (127 microA mM(-1)) monitoring of phenols. The detection limit is 0.2 nM at a signal-to-noise ratio of 3, the response time is less than 4 s reaching 95% of the steady-state value, and 70% of the activity is retained after 3 months.

Polymorphic CAG and GGN repeat lengths in the androgen receptor gene and prostate cancer risk: a population-based case-control study in China

The length of the polymorphic CAG trinucleotide repeat in the polyglutamine region of the androgen receptor (AR) gene is inversely correlated with the transactivation function of the AR. Because increased androgenic activity has been linked to prostate cancer and because an ethnic variation exists in the CAG repeat length, this polymorphism has been suggested to explain part of the substantial racial difference in prostate cancer risk. We conducted a population-based case-control study in China to investigate whether CAG and other polymorphisms of the AR gene are associated with clinically significant prostate cancer in this low-risk population. Genomic DNA from 190 prostate cancer patients and 304 healthy controls was used for direct sequencing to evaluate the relationship of CAG and GGN (polyglycine) repeat length in the AR gene. Relative to western men, our study subjects had a longer CAG repeat length, with a median of 23 and only 10% of the subjects having a CAG repeat length shorter than 20. Men with a CAG repeat length shorter than 23 (median length) had a 65% increased risk of prostate cancer (odds ratio, 1.65; 95% confidence interval, 1.14-2.39), compared with men with a CAG repeat length of 23 or longer. For the GGN tract (GGT3GGG1GGT2GGCn), based on the sequencing results from 481 samples, we are the first to show that although GGC regions in the polyglycine tract are highly variable, there are no mutations or polymorphisms in the GGT and GGG regions. More than 72% of the subjects had a GGN repeat length of 23, and those with a GGN repeat length shorter than 23 had a 12% increased risk of prostate cancer (95% confidence interval, 0.71-1.78), compared with those with > or = 23 GGN repeats. Our study not only confirms that Chinese men do have a longer CAG repeat length than western men but also represents the first population-based study to show that even in a very low-risk population, a shorter CAG repeat length confers a higher risk of clinically significant prostate cancer. These results imply that CAG repeat length can potentially serve as a useful marker to identify a subset of individuals at higher risk of developing clinically significant prostate cancer. Larger studies are needed to evaluate the combined effect of CAG and GGN repeats. Because of the significance of AR in prostate cancer, investigation of factors that interact with the polyglutamine region of the AR gene to alter AR function and modulate prostate cancer risk is an important area for future research.

[The changes of serum angiotensin converting enzyme activity in Type 2 diabetes and its vascular complications]

This investigation was made with reference to the changes of serum angiotensin converting enzyme (SACE) activity in type 2 diabetes and its vascular complications. SACE activity was studied in 127 type 2 diabetic patients and 90 healthy persons by using a spectrophotometric assay. The results showed SACE activity was obviously higher in diabetic patients (459.51 +/- 175.85 U) than in healthy persons (321.14 +/- 121.27 U); SACE activity was significantly higher in type 2 diabetic patients with diabetic nephropathy (548.27 +/- 166.60 U) than in patients without diabetic nephropathy (383.2 +/- 139.00 U), but there was no difference between patients with microalbuminuria and macroalbuminuria; no statistical difference was detected in SACE activity between diabetic patients with diabetic retinopathy (465.64 +/- 178.93 U) and without retinopathy (449.07 +/- 170.04 U); SACE activity was not associated with the course of diabetes, blood pressure, blood lipid and blood glucose. These data suggest that raised SACE activity might only play a role in the initiation of type 2 diabetes and diabetic nephropathy, but not relate to the progress of diabetic nephropathy, the onset of diabetic retinopathy and hypertension.

Detection of glutamate and gamma-aminobutyric acid in vitreous of patients with proliferative diabetic retinopathy

PURPOSE

To study the levels of glutamate and gamma-aminobutyric acid (GABA) in vitreous of patients with proliferative diabetic retinopathy (PDR) and to investigate their roles in retinal ischemia.

METHOD

Vitreous samples were collected from 25 patients (27 eyes) with PDR and 14 patients (14 eyes) with idiopathic macular hole. Glutamate and GABA detection were performed by high-performance liquid chromatography (HPLC).

RESULTS

Patients with PDR had significantly higher concentrations of glutamate and GABA than the control group. The glutamate level has a significantly positive correlation with GABA level.

CONCLUSION

Detection of glutamate and GABA in vitreous provides biochemical support for the mechanism and treatment of ischemic retinal damage in patients with PDR.

Monte Carlo verification of IMRT dose distributions from a commercial treatment planning optimization system

The purpose of this work was to use Monte Carlo simulations to verify the accuracy of the dose distributions from a commercial treatment planning optimization system (Corvus, Nomos Corp., Sewickley, PA) for intensity-modulated radiotherapy (IMRT). A Monte Carlo treatment planning system has been implemented clinically to improve and verify the accuracy of radiotherapy dose calculations. Further modifications to the system were made to compute the dose in a patient for multiple fixed-gantry IMRT fields. The dose distributions in the experimental phantoms and in the patients were calculated and used to verify the optimized treatment plans generated by the Corvus system. The Monte Carlo calculated IMRT dose distributions agreed with the measurements to within 2% of the maximum dose for all the beam energies and field sizes for both the homogeneous and heterogeneous phantoms. The dose distributions predicted by the Corvus system, which employs a finite-size pencil beam (FSPB) algorithm, agreed with the Monte Carlo simulations and measurements to within 4% in a cylindrical water phantom with various hypothetical target shapes. Discrepancies of more than 5% (relative to the prescribed target dose) in the target region and over 20% in the critical structures were found in some IMRT patient calculations. The FSPB algorithm as implemented in the Corvus system is adequate for homogeneous phantoms (such as prostate) but may result in significant under or over-estimation of the dose in some cases involving heterogeneities such as the air-tissue, lung-tissue and tissue-bone interfaces.

Energy- and intensity-modulated electron beams for radiotherapy

This work investigates the feasibility of optimizing energy- and intensity-modulated electron beams for radiation therapy. A multileaf collimator (MLC) specially designed for modulated electron radiotherapy (MERT) was investigated both experimentally and by Monte Carlo simulations. An inverse-planning system based on Monte Carlo dose calculations was developed to optimize electron beam energy and intensity to achieve dose conformity for target volumes near the surface. The results showed that an MLC with 5 mm leaf widths could produce complex field shapes for MERT. Electron intra- and inter-leaf leakage had negligible effects on the dose distributions delivered with the MLC, even at shallow depths. Focused leaf ends reduced the electron scattering contributions to the dose compared with straight leaf ends. As anticipated, moving the MLC position toward the patient surface reduced the penumbra significantly. There were significant differences in the beamlet distributions calculated by an analytic 3-D pencil beam algorithm and the Monte Carlo method. The Monte Carlo calculated beamlet distributions were essential to the accuracy of the MERT dose distribution in cases involving large air gaps, oblique incidence and heterogeneous treatment targets (at the tissue-bone and bone-lung interfaces). To demonstrate the potential of MERT for target dose coverage and normal tissue sparing for treatment of superficial targets, treatment plans for a hypothetical treatment were compared using photon beams and MERT.

Novel technique for three-dimensional visualisation and quantification of deformable, moving soft-tissue body parts

BACKGROUND

Three-dimensional (3D) imaging of delicate, moving soft-tissue body parts is very difficult. Our understanding of the muscles that control lip movements is based largely on histological and cadaveric studies, which provide scant information about dynamic morphology. Our aim was to develop an innovative scanning technique for the imaging and reconstruction of dynamic orofacial morphology by use of 3D and four-dimensional (4D, ie, 3D plus time) ultrasonography.

METHODS

Four volunteers (including one patient) underwent ultrasonography with 3D/4D imaging systems. To avoid deformation of the delicate orofacial structures, a water bath with an acoustic window was devised. The orofacial part was immersed in the bath throughout scanning, and a timer was used to synchronize lip movements with the 4D scan.

FINDINGS

4D views showed the functional differences in superficial and deep muscle groups of the lips, and clearly showed the changes occurring with movement of the lips and mouth. In the patient, a pathological layer and its extension corresponding to surface malformation were clearly identified.

INTERPRETATION

We have developed a prototype device that has made possible 3D and 4D examination of orofacial anatomy and function. With further refinement of the device and improvement in 4D acquisition timing, this technique may offer a new way of dynamically imaging and quantifying many soft-tissue parts in 3D without deforming structure or disturbing function.

Simultaneous use of two ultrasound scanners for motion-gated three-dimensional fetal echocardiography

The aim of this study was to determine whether or not simultaneous use of an additional Doppler transducer could provide sufficient cardiovascular motion information without significantly interfering with three-dimensional (3-D) cardiac structural data acquisition by a primary two-dimensional (2-D) transducer. To determine sources of interference, paired transducers were activated alternatively and simultaneously in and out of a water bath, with and without electrical insulating and electromagnetic shielding. To determine factors affecting interference, pairs were tested on a phantom with different separating distances and angles between paired ultrasound (US) beams and under different 2-D depths and Doppler scales. Results show that the dominant source of interference is acoustic cross talk. The severity was mainly affected by transducer pairing and by separating distances and angles, and the pattern by display settings. With optimised settings, sufficient structural and motion data were obtained simultaneously in 9 of 12 fetal hearts, and detailed 3-D views could be reconstructed free of motion artefacts, confirming the feasibility of using the method for motion-gated 3-D fetal cardiac imaging. New scanner design strategy was then proposed.

An amperometric biosensor based on the coimmobilization of horseradish peroxidase and methylene blue on a beta-type zeolite modified electrode

A new biosensor for the amperometric detection of hydrogen peroxide was developed based on the coimmobilization of horseradish peroxidase (HRP) and methylene blue on a beta-type zeolite modified glassy carbon electrode without the commonly used bovine serum albumin-glutaraldehyde. The intermolecular interaction between enzyme and zeolite matrix was investigated using FT-IR. The cyclic voltammetry and amperometric measurement demonstrated that methylene blue co-immobilized with HRP in this way displayed good stability and could efficiently transfer electrons between immobilized HRP and the electrode. The sensor responded rapidly to H2O2 in the linear range from 2.5 x 10(-6) to 4.0 x 10(-3) M with a detection limit of 0.3 microM. The sensor was stable in continuous operation.

Activation of signal transducer and activator of transcription-3 during proliferative phases of 3T3-L1 adipogenesis

Signal transducer and activator of transcription-3 (STAT3) is abundantly expressed in preadipocytes and adipocytes, but little is known about its activation status or functional role during adipogenesis. In this report we investigate STAT3 activation in 3T3-L1 preadipocytes before and after differentiation into adipocytes. STAT3 was highly tyrosine phosphorylated and bound to DNA in proliferating preadipocytes, but not in growth-arrested preadipocytes or adipocytes. In growth-arrested confluent preadipocytes, induction of differentiation with methylisobutylxanthine, dexamethasone, and high dose insulin led to a delayed, but prolonged (3-day), increase in STAT3 tyrosine phosphorylation. This increase in STAT3 phosphorylation coincided temporally with postconfluent preadipocyte mitotic clonal expansion. Insulin and methylisobutylxanthine alone, but not dexamethasone, induced STAT3 tyrosine phosphorylation in postconfluent cells. Diminution of endogenous STAT3 expression by antisense morpholino oligonucleotides significantly decreased preconfluent preadipocyte proliferation. Collectively, these findings suggest a regulatory role for STAT3 during the proliferative phases of adipogenesis.

[Polymorphism of ACE gene and its relationship with serum ACE activity in the Hans in Chengdu region]

This study was aimed at the angiotensin converting enzyme (ACE) gene insertion/deletion(I/D) polymorphism distribution in Chinese and its relationship with serum ACE activity(SACE). SACE activity and ACE gene polymorphism in 90 healthy persons in Chengdu region were investigated using a spectrophotometric assay and the PCR technique, respectively. The results showed that, in the Hans, DD genotype of ACE gene was 18%, DI genotype 44%, and II genotype 38%. Allele frequencies were 0.40 for the D allele and 0.60 for the I allele. There were significant relationships between ACE I/D polymorphism and SACE activity. The results suggest that ACE genotype distribution be different between races, that II genotype and I allele be more frequent in Chinese, and that SACE activity be under the influence of a genetic polymorphism of ACE in Chinese.

Induction of cell cornification and enhanced squamous-cell marker SPRR1 gene expression by phorbol ester are regulated by different signaling pathways in human conducting airway epithelial cells

Phorbol ester is a strong inducer for both cell cornification and squamous-cell marker SPRR1 gene expression in conducting airway epithelial cells. However, the signaling pathways involved in the regulation of both events have not been completely elucidated. The current study focuses on the common and divergent pathways involved in the induction of these two activities by phorbol-13-myristate-12-acetate (PMA). Using a protein kinase (PK) C inhibitor, bisindolylmaleimide I, PMA-induced cell cornification and SPRR1 gene expression were abolished. Further, a PKC activator, indolactam V, induced cell cornification in the absence of PMA treatment. These results suggest a PKC-dependent signaling pathway for both gene induction and enhanced cell cornification by PMA. However, a mitogen-activated protein kinase-specific inhibitor, PD98059, could only block the gene induction event but failed to prevent cell cornification induced by PMA. These results suggest that diverse signaling pathways after PKC activation by PMA are involved in the regulation of these two events.

Spectroelectrochemical investigation of direct electron transfer between resting horseradish peroxidase and its oxidation states promoted by DNA

Direct electron transfer between resting horseradish peroxidase (HRP) and its oxidation states was observed at a gold mesh electrode in a spectroelectrochemical cell in the presence of DNA. The conversion between HRP and the oxidized species induced electrochemically was found to be reversible and parallel to that initiated chemically. DNA played an important role as electron carrier and promoted the electron transfer between HRP and the electrodes. Voltammetric results and CD spectra indicated an interaction between HRP and DNA. Moreover, the secondary structure of HRP was slightly disturbed upon mixing with DNA. The direct spectroelectrochemistry of HRP at a gold mesh electrode presented new information on its bioelectrochemical characteristics.

Construction of La-tPA vector and expression in the mammary gland of transgenic mice

Expression vectors of long acting human tissue plasminogen activator (La-tPa) in the mammary gland was constructed using the promoters of sheep beta-lactoglobulin gene (BLG, 5 kb) containing the first and the second introns obtained by PCR. Transgenic mice were established by microinjection. 540 fertilized eggs were injected and 6 transgenic mice were screened out from the offspring by PCR and Southern Blot analysis. The foreign gene integrating rate was 32%. The expression of La-tPA in mammary glands of transgenic mice was confirmed by milk assay and Northern blot analysis. Expression level of La-tPA reached 6 ug/ml in milk of transgenic mice.

[Study on the role of superoxide anion in promoting proliferation and transformation of rat liver oval cell line WB-E344]

OBJECTIVE

To study the role of superoxide anion (O2.-) in promoting proliferation and transformation of rat liver oval cell strain WB-F344.

METHODS

WB-F344 cells cultured were stimulated directly by O2.- generated by interaction of xanthine with xanthine oxidase (X-XO). The effect of O2.- in promoting proliferation of WB cells was investigated by using MTT colorimetric analysis, 3H-Tdr incorporation liquid scintillation counter and 3H-Tdr incorporation autoradiography. WB cells initiated with N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) were promoted by stimulating continuously with O2.- of low concentration (X: 100 mumol/L, XO: 0.2 mU/ml). The transformation effect was tested by morphologic observation, karyotype analysis and anchorage-independent growth assay.

RESULTS

Proliferation of WB cells was induced obviously by O2.- of low concentration for only one time. WB cells initiated with MNNG were transformed by action with O2.- of low concentration continuously for 15 d and typical morphologic character of transformed cells was observed. In karyotype analysis the cells chromosome number changed and the frequency of structure aberration raised dramatically. Also the transformed cells could form clone on self-solid culture medium.

CONCLUSIONS

The biological effect of O2.- was related closely with its dose; The effects of low concentration in promoting proliferation and transformation of liver oval cells indicate its important role in hepatocarcinogenesis and antioxidation was able to provide a new clue in prevention and cure of hepatoma.

[Improved liposome encapsulated hemoglobin by electret technology and its influence on the blood rheologic behavior in vitro]

To study the influence of different electret properties of Liposome Encapsulated Hemoglobin(LEH) on the blood rheologic behavior in vitro, four kinds of LEH have been prepared. Their electret properties have been determined by using Thermally Stimulated Depolarization Current(TSDC). The results show that 4# LEH, whose Ta is 12 degrees C and Ia is -5.6 x 10(-9) A, has the best electret property, furthermore, the results of the thrombus formation in vitro also show that the addition of 4# LEH induces the lightest thrombus figuration in vitro. It is obvious that the rational improvement of the electret property of LEH can meliorate the surface charge of blood and effectively inhibit the formation of thrombus.

[Spectrum of mycotic keratitis in China]

OBJECTIVE

To investigate the spectrum of mycotic keratitis in China.

METHODS

We scraped and evaluated 615 mycotic keratitis in microbiology laboratories of Zhengzhou (central China), Shijiazhuang (north China) and Guangzhou (south China) in the twenty-two years between Jan. 1, 1975 and Jun. 30, 1997.

RESULTS

Organisms of 18 genuses and 615 species isolated from corneal ulcers were found. Fusarium species were isolated the most frequently (65.0% in Zhengzhou, 33.3% in Shijiazhuang and 39.2% in Guangzhou), followed by Aspergillus (20.5% in Zhengzhou, 21.7% in Shijiazhuang, 30.7% in Guangzhou), Penicillium (3.6% in Zhengzhou, 11.6% in Shijiazhuang) and Curvularis (13.1% in Guangzhou). Between Jan. 1, 1975 and Dec. 31, 1986, Aspergillus species were most commonly isolated in Guangzhou (48.5%), followed by Fusarium (27.7%) and Penicillium (14.27%).

CONCLUSIONS

Just as different regions of the world are characterized by specific endemic infections, the predominating organisms in corneal fungal infections also vary throughout the world. These regional differences in causative organisms in mycotic keratitis are clinically important because they influence the initial and more definite therapy. This study shows that Fusarium species are the most common organisms of mycotic keratitis in China.