Angiotensinogen gene polymorphisms M235T/T174M: no excess transmission to hypertensive Chinese

The gene encoding angiotensinogen (AGT) has been widely studied as a candidate gene for hypertension. Most studies to date have relied on case-control analysis to test for an excess of AGT variants among hypertensive cases compared with normotensive controls. However, with this design, nothing guarantees that a positive finding is due to actual allelic association as opposed to an inappropriate control population. To avoid this difficulty in our study of essential hypertension in Anqing, China, we tested AGT variants using the transmission/disequilibrium test, a procedure that bypasses the need for a control sample by testing for excessive transmission of a genetic variant from parents heterozygous for that variant. We analyzed two AGT polymorphisms, M235T and T174M, which have been associated with essential hypertension in whites and Japanese, using data on 335 hypertensive subjects from 315 nuclear families and their parents. Except in the group of subjects younger than 25 years, M235 and T174 were the more frequently transmitted alleles. We found that 194 parents heterozygous for M235T transmitted M235 106 times (P=0.22) and that 102 parents heterozygous for T174M transmitted T174 60 times (P=0.09). Stratifying offspring by gender, M235 and T174 were transmitted 60 of 106 times (P=0.21) and 44 of 75 times (P=0.17), respectively, in men, and 46 of 88 times (P=0.75) and 16 of 27 times (P=0.44), respectively, in women. Our results were also negative in all age groups and for the affected offspring with blood pressure values >/=160/95 mm Hg. Thus, this study provides no evidence that either allele of M235T or T174M contributes to hypertension in this Chinese population.

[The percentage of free prostate specific antigen used in detecting prostate cancer]

OBJECTIVE

To evaluate the value of the percentage of free prostate specific antigen in detecting prostate cancer.

METHODS

Serum free prostate specific antigen (F-PSA) and total PSA were measured with immunoradiometric assay, and the free/total PSA ratio was calculated. In 117 patients, 31 had prostate carcinoma and 86 BPH.

RESULTS

The free/total PSA ratio was lower in patients with prostate cancer than in those with BPH. If the total serum PSA level was limited with in 4 - 10 ng/ml, the free/total PSA ratio can be used in the differential diagnosis of prostate cancer and BPH except total PSA.

CONCLUSIONS

The free/total PSA ratio can be used in the differential diagnosis of prostate cancer and BPH, especially when serum PSA level is limited with in 4 - 10 ng/ml.

[Studies on immune responses in mice to expressed products from CSP gene of Plasmodium falciparum FCC1/HN isolate]

AIM

To construct the eukaryotic expression system with pcDNA3-PfCSP/HeLa for CSP gene of Plasmodium falciparum, and to observe the immune responses in BALB/c mice induced by the expressed proteins.

METHODS

The recombinant plasmid pcDNA3-PfCSP was transformed into mammalian cell line of human HeLa cells. The expressed protein was isolated and analyzed by SDS-PAGE and used for immunization of BALB/c mice by subcutaneous, intravenous or intraperitoneal administration, respectively. ELISA, Western blotting, T lymphocyte proliferation test, natural killer cell activity and CD4+ and CD8+ T cells detection were used for observation of the level of humoral and cellular immune responses.

RESULTS

Immune sera strongly reacted with the expressed protein. The titer of the antibodies was up to 1:6,400 by ELISA. Western blotting analysis revealed a specific band at 38.3 kDa. The specific proliferative response with immunized BALB/c mice spleen cells was remarkablely higher than that with control ones. The ratio of CD4+ and CD8+ T cells and the NK cell activity were significantly higher in the immunization group than that in the control groups.

CONCLUSION

The humoral and cell-mediated immune responses and elevated NKC activity to expressed products with the eukaryotic expression system can specifically be detected in BALB/c mice to generate, indicating that the expressed protein could enhance immune activity in mice.

Topology of Euglena chloroplast protein precursors within endoplasmic reticulum to Golgi to chloroplast transport vesicles

Euglena chloroplast protein precursors are transported as integral membrane proteins from the endoplasmic reticulum (ER) to the Golgi apparatus prior to chloroplast localization. All Euglena chloroplast protein precursors have functionally similar bipartite presequences composed of an N-terminal signal peptide domain and a stromal targeting domain containing a hydrophobic region approximately 60 amino acids from the predicted signal peptidase cleavage site. Asparagine-linked glycosylation reporters and presequence deletion constructs of the precursor to the Euglena light-harvesting chlorophyll a/b-binding protein of photosystem II (pLHCPII) were used to identify presequence regions translocated into the ER lumen and stop transfer membrane anchor domains. An asparagine-linked glycosylation site present at amino acid 148 of pLHCPII near the N terminus of mature LHCPII was not glycosylated in vitro by canine microsomes while an asparagine-linked glycosylation site inserted at amino acid 40 was. The asparagine at amino acid 148 was glycosylated upon deletion of amino acids 46-146, which contain the stromal targeting domain, indicating that the hydrophobic region within this domain functions as a stop transfer membrane anchor sequence. Protease protection assays indicated that for all constructs, mature LHCPII was not translocated across the microsomal membrane. Taken together with the structural similarity of all Euglena presequences, these results demonstrate that chloroplast precursors are anchored within ER and Golgi transport vesicles by the stromal targeting domain hydrophobic region oriented with the presequence N terminus formed by signal peptidase cleavage in the vesicle lumen and the mature protein in the cytoplasm.

[Clinical analysis of spontaneous perforation of abdominal viscera in patients with severe viral hepatitis]

Eight out of 246 patients with severe viral hepatitis were complicated with spontaneous abdominal viscera perforation. The eight patients all had serious digestive symptoms, orange green colour in skin, swollen abdomen with ascites, abdominal pain. All cases were diagnosed by liver function examination, colour ultrasonography, x-ray examination, abdominal puncture and one case by operation. Among these 8 cases, 3 cases had perfornation of stomach, 3 cases had perforation of gall bladder and 2 cases had perforation of small intestine. Though emergancy treatment had been applied, only one case was saved.

[Nucleotide sequence analysis of a species specific probe by an inserted fragment from recombinant plasmid pCX7 of L. interrogans sensu stricto serovar lai]

The etiological agents of leptospirosis are the pathogenic leptospires (L. interrogans sensu lato) which can be divided into 223 serovars organized into 23 serogroups. The serovar remains the basic taxon, but serotyping may now be accomplished and recognized by acceptable methods. Complementary molecular approaches are being used extensively to assess genetic relatedness amongst leptospires with restriction endonuclese analysis (REA), pulse field gel electrophoresis (PFGE) and DNA-DNA hybridization as well established tools. However, the method is cumbersome and unsuitable for routine application. To develop a sensitive and specific method for identification of pathogenic leptospires, a genomic library of L. interrogans sensu stricto serovar lai was constructed with the plasmid vector pUC9. A recombinant plasmid, designated pCX7 which has homologous fragment of pathogenic leptospires was screened from the bank. pCX7 could recognize pathogenic leptospiral DNA fragment 1.7 kb of strain 017 without cross hybridization to nonpathogenic leptospiral DNA. Inserted fragment of pCX7 DNA sequencing was performed by Dr. Yan Zhengxin (Max-Plank-Institut fur Biology, Tubingen, Germany). Insert fragment was cloned into pBluescript and sequenced by using ABI(Applied Bio. Systems, Model 373A). Nucleotide sequences were analyzed by Dr. Xiao Jianguo (Texas University Medical School and School of Public Health, Center for Infectious Diseases) using a suit of computer program (NIH). One open reading frame of 306 nucleotids were identified. There were identifiable initiation codons, terminators, pribnow box and sextama box within the sequenced regions. These results further confirmed that the little homology between L. interrogans sensu strito and L. borgpeterseni serovar javanica, L. inadai serovar ranarun and serovar manhao (L. genomospecies 2), L. biflexa serovar patoc, L. illini. pCX7 DNA probe could provide a base for identification and classification of leptospires.

Pharmacokinetics of intravenous arsenic trioxide in the treatment of acute promyelocytic leukemia

OBJECTIVE

To study the pharmacokinetics and metabolism of arsenic trioixide (As2O3) and its main side effects.

METHOD

As2O3 was administered intravenously at the dose of 10 mg per day for the treatment of 8 relapsed acute promyelocytic leukemia (APL) patients. The arsenic content was measured by Gas-phase chromatography.

RESULTS

The plasma maximal concentration (Cpmax) was 0.94 +/- 0.37 mg/L (x +/- s), time to peak concentration (Tp) was 4 hours, plasma distribution half-time (t1/2 alpha) and elimination half-time (t1/2 beta) were 0.89 +/- 0.29 hours and 12.13 +/- 3.31 hours, respectively. Apparent distribution volume (Vc) was 3.83 +/- 0.45 L, system clearance (CLs) was 1.43 +/- 0.17 L/h, and area under curve (AUC) was 7.25 +/- 0.97 mg.h/L. The continuous administration of As2O3 did not alter its pharmacokinetic behaviors. During As2O3 treatment, 24-hour arsenic content in urine accounted for 1%-8% of the daily dose (10 mg). When arsenic accumulation in hair and nail increased continuously, the peak concentration could be five to seven-fold higher than that of pre-treatment. Importantly, arsenic contents in both urine and hair or nail declined gradually after drug withdrawal. No bone marrow suppression or severe organ-impairment was found.

CONCLUSION

As2O3 is a relatively safe and effective remedy in the treatment of patients with relapsed APL, in spite of certain degree of arsenic accumulation in some tissues.

[Cloning, characterization and expression in E. coli of the flagellin gene from Leptospira interrogans Serovar lai]

To obtain a large amount of recombinant endoflagellin protein of leptospsira, we have cloned the fla B gene from Leptospira interrogans serovar lai strain 017, which encodes the core flagellar protein. The entire open reading frame was amplified by polymerase chain reaction, which was digested with endonucleases Sal I and Cla I, then was orientationally cloned into the expression vector, pT7-7. The recombinant plasmid was transformed into Escherichia coli JM109 (DE3) for expression. After induction with IPTG, a 34 kd expression protein was detected by SDS-PAGE. The amount of recombinant protein was estimated as 11.8% of the whole bacterial lysate proteins. Probed with insert fragments, Southern blot analysis indicated that possibly two gene related to fla B were present in the genome of Leptospira interrogans serovar lai stain 017. Western blot analysis showed that the 34 kd expression protein reacting with rabbit polyclonal antiserum raised against leptospira endflagellin.

Blood pressure at age 3-24 years in a rural community in Anhui, China

PURPOSE

This community-based study in Anhui, China examined the sex-specific pattern of blood pressure (BP) and its major determinants between age 3 and 24 years.

METHODS

BP, height, weight, and related covariates were obtained from all eligible subjects by consistent methods. A generalized additive model was used to explore independent relations between BP and covariates. The sample for analyses included a total of 14,277 subjects (7244 males and 7033 females).

RESULTS

Systolic blood pressure (SBP) increased linearly with age to an apparent plateau around the age of 15 years in girls and 20 years in boys. Diastolic blood pressure (DBP) essentially paralleled SBP. Until the age of 10, both SBP and DBP were similar in boys and girls; thereafter, values for boys surpassed those for girls with an average difference of 9 mmHg and 4 mmHg for SBP and DBP, respectively, at 20 years of age. This sex difference appeared to persist into early adulthood. The independent relation between BP and each of the three major determinants (age, height, and weight) was nonlinear over the age range studied. Sex-specific regression models with linear terms for age, height and weight were developed for each of four age groups (3-9, 10-14, 15-19, 20-24 years). The 5th, 10th, 90th, and 95th percentiles based on the percentage of predicted values can serve as the cutoffs for low, normal-low, normal-high, and high BP. The predicted values were derived from the above regression models that take into account an individual's sex, age, height, and weight.

CONCLUSIONS

This analysis provided important basis for classification of hypertension status and subsequent investigation of environmental risk factors in this population.

[Determination of sulphate ion in environmental water samples by flow injection spectrophotometry]

Sulphate ion in environmental water samples was successfully determined by flow injection spectrophotometry, based on the reaction with barium dimethylsulphonazo (III) complex. The linear range is 1-4 mg/L, the recoveries are 95-106%, relative standard deviation is 1.5% (n = 10) and the precision of the procedure for long time (about 4h) < 5%, respectively.

Rat strain minimally influences anesthetic and convulsant requirements of inhaled compounds in rats

We assessed the effect of rat strain on susceptibility to anesthesia and convulsions produced by inhaled compounds. We determined the minimum alveolar anesthetic concentration (MAC) of desflurane and nitrous oxide, and the convulsive 50% effective dose (ED50) of 1,2-dichlorohexafluorocyclobutane, flurothyl, and difluoromethyl-1-chlorotetrafluoroethyl ether in five strains (three inbred [Long Evans, Sprague-Dawley, and Wistar] and two outbred [Fischer and Brown Norway]). Strain had slight effects on anesthetic potency, the strains with the highest MAC values (Long Evans and Brown Norway) having values < or =28% greater than the strains with the lowest values (Sprague Dawley and Wistar). MAC for nitrous oxide correlated directly with MAC for desflurane as a function of strain. MAC for either desflurane or nitrous oxide correlated inversely with the convulsive ED50 of 1,2-dichlorohexafluorocyclobutane, but correlated poorly (and directly) with the convulsive ED50 of the remaining compounds. Convulsivity varied little as a function of strain (greatest difference 21%) and did not vary consistently as a function of strain. No consistent difference was seen between inbred versus outbred strains.

IMPLICATIONS

Rat strain has a minimal effect on the potency of inhaled anesthetics or the convulsant activity of inhaled compounds. It seems that the sites acted on by inhaled compounds to produce anesthesia and convulsions are conserved across common rat strains.

[Immunoprotection in guinea pigs using DNA recombinant plasmid rpDJt and expressed protein P68 in L. interrogans serovar lai]

Immunoprotection against the infection by Leptospira interrogans serogroup Icterohemorrhagiae serovar lai strain 017 was demonstrated in guinea pigs vaccinated with DNA recombinant plasmid rpDJt and expressed protein P68 derived from genomic library of Leptospira strain 017. Thirty days after active immunization, each group received intraperitoneally (1/2 dose) and subcutaneously (1/2 dose) inoculum of L. interrogans serovar lai stain 017; cultures were adjusted to 5 x 10(8) cells/ml. All guinea pigs were observed for 10 days after challenge. Survival (%) of P68 group was 100(7/7); P23 group was 75(3/4); group rpDJt was 77(10/13); group lack recombinant (control) pT7-7 was 25 (3/12), and group with whole-cell inactivated vaccine was 93(13/14). Although the protective antigen in the leptospires has yet to be determined, it is evident that expressed protein P68 conferred a high degree of immunoprotection in guinea pigs.

[Therapeutic effect of Shengmai injection on respiratory function in chronic obstructive pulmonary disease]

OBJECTIVE

To explore the therapeutic effect of Shengmai injection (SMI) on respiratory function in chronic obstructive pulmonary disease (COPD).

METHODS

Twenty patients with COPD were continuously treated with SMI by intravenous drip in 14 days and examined the lung vital capacity (VC), forced vital capacity (FVC), forced vital capacity of the first second (FEV1), FEV1/FVC, maximum voluntary ventilation (MVV), maximum inspiratory pressure (MIP), load respiratory time (LT), 6 minute walk distance (6 MWD), arterial blood gas analysis, and Brog dyspnea scale before and after treatment respectively and compared with itself or control group.

RESULTS

After treatment all parameters of the treatment group were better than those of control group or itself before treatment except for FVC and FEV1/FVC. There were significant difference (P < 0.05).

CONCLUSION

SMI can improve respiratory function in COPD. So it is an effective rehabilitative measure in treating COPD.

Minimum alveolar concentrations of noble gases, nitrogen, and sulfur hexafluoride in rats: helium and neon as nonimmobilizers (nonanesthetics)

We assessed the anesthetic properties of helium and neon at hyperbaric pressures by testing their capacity to decrease anesthetic requirement for desflurane using electrical stimulation of the tail as the anesthetic endpoint (i.e., the minimum alveolar anesthetic concentration [MAC]) in rats. Partial pressures of helium or neon near those predicted to produce anesthesia by the Meyer-Overton hypothesis (approximately 80-90 atm), tended to increase desflurane MAC, and these partial pressures of helium and neon produced convulsions when administered alone. In contrast, the noble gases argon, krypton, and xenon were anesthetic with mean MAC values of (+/- SD) of 27.0 +/- 2.6, 7.31 +/- 0.54, and 1.61 +/- 0.17 atm, respectively. Because the lethal partial pressures of nitrogen and sulfur hexafluoride overlapped their anesthetic partial pressures, MAC values were determined for these gases by additivity studies with desflurane. Nitrogen and sulfur hexafluoride MAC values were estimated to be 110 and 14.6 atm, respectively. Of the gases with anesthetic properties, nitrogen deviated the most from the Meyer-Overton hypothesis.

IMPLICATIONS

It has been thought that the high pressures of helium and neon that might be needed to produce anesthesia antagonize their anesthetic properties (pressure reversal of anesthesia). We propose an alternative explanation: like other compounds with a low affinity to water, helium and neon are intrinsically without anesthetic effect.

Identification of novel factors that regulate GnRH gene expression and neuronal migration

We used differential display PCR on two GnRH producing cell lines to identify genes involved in GnRH gene expression and neuronal migration. RNA from Gn10 cells (derived from a tumor in the olfactory area when GnRH neurons are migrating and make low levels of GnRH) and from GT1-7 cells (derived from a tumor in forebrain when GnRH neurons are postmigratory and make high levels of GnRH) was reverse transcribed into cDNA. The cDNA was amplified using three anchored primers and eight random primers from each cell line and products from duplicate reactions electrophoresed in parallel in a denaturing acrylamide gel. Differentially expressed cDNAs were excised, reamplified and used as probes in Northern analysis of total RNA from each cell line to confirm differentially expressed RNA. The cDNAs were sequenced and compared to the Genbank database. Four of five clones isolated from GT1-7 GnRH neurons are novel, while four of five clones isolated from Gn10 cells have homology to known DNA sequences. One clone, Gn8-01 encodes adhesion related kinase (Ark), a molecule that has an N-terminal domain characteristic of cell adhesion molecules and whose kinase domain may play a role in protection from apoptosis. Together these data support the usefulness of the technique to identify novel genes that play a role in the control of GnRH expression and neuronal migration.

Molecular cloning and expression characterization of a rice K+ channel beta subunit

K+ channel proteins native to animal membranes have been shown to be composed of two different types of polypeptides: the pore-forming alpha subunit and the beta subunit which may be involved in either modulation of conductance through the channel, or stabilization and surface expression of the channel complex. Several cDNAs encoding animal K+ channel beta subunits have been recently cloned and sequenced. We report the molecular cloning of a rice plant homolog of these animal beta subunits. The rice cDNA (KOB1) described in this report encodes a 36 kDa polypeptide which shares 45% sequence identity with these animal K+ channel beta subunits. and 72% identity with the only other cloned plant (Arabidopsis thaliana) K+ channel beta subunit (KAB1). The KOB1 translation product was demonstrated to form a tight physical association with a plant K+ channel alpha subunit. These results are consistent with the conclusion that the KOB1 cDNA encodes a K+ channel beta subunit. Expression studies indicated that KOB1 protein is more abundant in leaves than in either reproductive structures or roots. Later-developing leaves on a rice plant were found to contain increasing levels of the protein with the flag leaf having the highest titer of KOB1. Leaf sheaths are known to accumulate excess K+ and act as reserve sources of this cation when new growth requires remobilization of K+. Leaf sheaths were found to contain higher levels of KOB1 protein than the blade portions of leaves. It was further determined that when K+ was lost from older leaves of plants grown on K+-deficient fertilizer, the loss of cellular K+ was associated with a decline in both KOB1 mRNA and protein. This finding represents the first demonstration (in either plants or animals) that changes in cellular K+ status may specifically alter expression of a gene encoding a K+ channel subunit.

IS6110 transposition and evolutionary scenario of the direct repeat locus in a group of closely related Mycobacterium tuberculosis strains

In recent years, various polymorphic loci and multicopy insertion elements have been discovered in the Mycobacterium tuberculosis genome, such as the direct repeat (DR) locus, the major polymorphic tandem repeats, the polymorphic GC-rich repetitive sequence, IS6110, and IS1081. These, especially IS6110 and the DR locus, have been widely used as genetic markers to differentiate M. tuberculosis isolates and will continue to be so used, due to the conserved nature of the genome of M. tuberculosis. However, little is known about the processes involved in generating these or of their relative rates of change. Without an understanding of the biological characteristics of these genetic markers, it is difficult to use them to their full extent for understanding the population genetics and epidemiology of M. tuberculosis. To address these points, we identified a cluster of 7 isolates in a collection of 101 clinical isolates and investigated them with various polymorphic genetic markers, which indicated that they were highly related to each other. This cluster provided a model system for the study of IS6110 transposition, evolution at the DR locus, and the effects of these on the determination of evolutionary relationships among M. tuberculosis strains. Our results suggest that IS6110 restriction fragment length polymorphism patterns are useful in grouping closely related isolates together; however, they can be misleading if used for making inferences about the evolutionary relationships between closely related isolates. DNA sequence analysis of the DR loci of these isolates revealed an evolutionary scenario, which, complemented with the information from IS6110, allowed a reconstruction of the evolutionary steps and relationships among these closely related isolates. Loss of the IS6110 copy in the DR locus was noted, and the mechanisms of this loss are discussed.

[Primitive neuroectodermal tumor of bone and soft tissue]

OBJECTIVE

To study the pathological characteristics of primitive neuroectodermal tumor (PNET) of bone and soft tissue.

METHOD

Five patients with bone and soft tissue of PNET (2 men and 3 women) were studied by light microscope and immunohistochemistry. The age of the patients was 18, 18, 43, 14, 32 years and the primary sites of involvement were the ilium (n = 2), axillary fossa (n = 1), condyle of femur (n = 1), and diploe (n = 1). X-ray films showed bone osteolytic destruction, and no periosteal reaction or calcification. Surgery was performed in the patients.

RESULT

All patients received combined chemotherapy and 3 received radiotherapy. Three patients died of metastatic tumor of lung 20, 13, and 5 months after invasion. 1 patient metastatic tumor of lung 20 months after invasion, and 1 patient bone extensive metastasis 1.5 months after surgery.

CONCLUSION

The treatment of PNET of bone and soft tissue awaits further study.

Phylogenetic relationships of toads in the Bufo bufo species group from the eastern escarpment of the Tibetan Plateau: a case of vicariance and dispersal

Phylogenetic relationships among Tibetan populations of the Bufo bufo species group are investigated using 1063 bases of mitochondrial DNA sequence from the genes encoding ND1 (subunit one of NADH dehydrogenase), tRNA(Ile), tRNA(Gln), tRNA(Met), and ND2. The aligned sequences contain 181 phylogenetically informative characters across all taxa sampled. Two hypotheses for colonization of the Tibetan Plateau are tested. A vicariant hypothesis predicts monophyly of populations from high elevations. A dispersalist hypothesis predicts monophyly of populations in each of two river drainages (Yangtze and Yellow rivers), which requires nonmonophyly of populations from high elevations. Both hypotheses are rejected in favor of a third hypothesis that combines elements of vicariance and dispersal. The most parsimonious phylogenetic tree places the high-elevation species, B. andrewsi, as the sister taxon to the other Asian Bufo populations; these high-elevation populations are postulated to have had a vicariant origin approximately 5 million years before present. The high-elevation population recognized as B. minshanicus is nested within low-elevation populations of B. gargarizans and is suggested to have dispersed onto the Tibetan Plateau more recently.

Angiotensinogen gene and hypertension in Chinese

The renin-angiotensin system plays a major role in regulating blood pressure and maintaining electrolyte and volume homeostasis. Previously, the angiotensinogen gene, which encodes the key substrate for renin within this system, has been reported linked to and associated with essential hypertension in White Europeans, African-Caribbeans, and Japanese. Therefore, we investigated whether the angiotensinogen gene might be similarly implicated in the pathogenesis of essential hypertension in Chinese by carrying out linkage analysis in 310 hypertensive sibling pairs. Genotypes for two diallelic DNA polymorphisms observed at amino acid residues 174 (T174M) and 235 (M235T) within the coding sequence and for two highly informative dinucleotide (GT)-repeat sequences (one in the 3' flanking region, and one at a distance of 6.1 cM from the gene) were determined. Affected sibpair analysis conducted according to three different algorithms (S.A.G.E./SIBPAL, MAPMAKER/ SIBS, and APM methods) revealed no evidence for linkage of the angiotensinogen gene to hypertension. Our data indicate that molecular variants of this gene do not appear to contribute materially to the pathogenesis of primary hypertension among Chinese (a notion supported by concomitant, direct estimates of power), and that the disease relevance of this gene may vary therefore depending on ethnicity.

[Clinico-pathologic study of Ewing's sarcomas of bone and soft tissue and peripheral primitive neuroectodermal tumors]

OBJECTIVE

To study the diagnosis and differentiation of EW and PNET.

METHODS

Fourteen cases of Ewing's sarcomas (EW) and peripheral primitive neuroectodermal tumors (PNET) were studied by light microscopy, immunohistochemistry and electron microscopy (EM). Twelve cases were followed up. Schmidt criterion was used for the differential diagnosis of EW and PNET.

RESULTS

There were 6 cases of EW and 8 cases of PNET. Six of 8 PNET cases had Homer-Wright (H-W) rosettes. In this series, 12/14 cases were positive for O13 (HBA71) staining. NSE was positive in 3 cases of EW. All PNET cases were positive for neural markers, and 5 of them were positive for more than two of these markers. Electronmicroscopically, there were neurosecretory granules (4/4 cases), nerve-like protrusions and microfilaments (1/4 case) in PNET. In 3 of 6 EW and 1 of 6 PNET, PAS staining was positive. During the follow-up period from 2 months to 5 years, 3 cases with intraosseous EW remain alive and free of tumor. The remaining patients are dead or having their tumors metastasized.

CONCLUSION

EW is more primitive in cell differentiation, while PNET has more neural differentiation. The presence of H-W rosettes is an important morphologic feature of PNET. To differentiate EW from PNET is of clinical significance O13 is a useful marker for the diagnosis of EW/PNET.