[The changes of PRA, ATII, ald, ET and ANP in patients with left ventricular diastolic heart failure and intervention with enalapril]

Fifty patients with left ventricular diastolic heart failure (LVDHF), and 35 patients with left ventricular systolic heart failure (LVSHF) diagnosed by clinical manifestation and radionuclide ventriculography were studied and 20 normal persons served as controls. Plasma renin activity (PRA), angiotensin I (AT I), aldosterone (ALD), endothelin (ET) and atrial natriuretic peptide (ANP) concentrations were measured by radioimmunoassay. Fifty patients with LVDHF were divided into treatment group and control group in a randomized, double blind, control method. Enalpril, CoQ10 and VitE were given in treatment group while only CoQ10 and VitE were given in control group. The therapeutic efficacy was evaluated after 8 weeks of treatment. The results showed that plasma concentration of PRA, AT I, ALD, ET and ANP were increased in LVDHF, but lower than those in LVSHF. After treatment with enalapril plasma PRA was increased while AT I, ALD and ET level were decreased significantly but ANP level had no change in treatment group.

[Studies on synthetic peptide. XX: the antigenicity and linear epitope map of synthetic peptide hepatitis C virus]

Hepatitis C virus (HCV), the major causative agent of post transfusion non-A, non-B hepatitis (NANB), had been cloned and expressed. According to the protein sequence of HCV-BK and its epitope profiles which combined the hydrophilicity, accessibility, flexibility, antigenicity, charge distribution and HPLC reserve coefficient of protein using the "Goldkey" computer program, we designed and synthesized the following peptides: P1(475-495), P3(449-468), P4(658-663), P5(645-663), P6(484-489), P7(475-489), P15(655-662), P16(230-237), P17(225-237), P18(1220-1240), P19(1694-1735), P24(1230-1240), P25(1482-1493), P26(384-389), P27(2355-2389). The results of ELISA showed that P6(60% positive results) and P19(63% positive results) testing with PT-HC of Gu An, Hebei province were the major antigens in NS1 and in NS4 region, respectively.

A case-control study of risk factors for hepatocellular carcinoma in Henan, China

A case-control study was carried out to investigate risk factors in the development of hepatocellular carcinoma (HCC) in Henan, China. A total of 152 patients with HCC and 115 control patients with nonhepatic disease were included in this study. The risk factor analysis indicated that individual history of liver disease (odds ratio [OR]=11.77; 95% confidence interval [CI]=3.94-35.18), family history of liver disease (OR=11.80, 95% CI=2.75-50.61), drinking of alcohol (OR=1.06, 95% CI=1.02-1.10), corn consumption (OR=19.43, 95% CI=3.67-102.98), peanut and peanut oil consumption (OR=13.75, 95% CI=3.69-51.16), and infection with hepatitis B virus (HBV) (OR=44.59, 95% CI=12.54-158.49) were significantly different between the case and control groups (P < 0.01). We also found that there was a dose-response relationship between drinking of alcohol and development of HCC, whereas heavy drinkers experienced an approximately 3-4-fold risk increase compared with nondrinkers. In further analysis, a 1:1 pair-matched case-control study was performed. One hundred thirteen of 152 HCC patients were randomly selected to be pair-matched by sex and age (+/-5 years) with the controls with nonhepatic disease. The results from the 1:1 pair-matched case-control study were consistent with the results from the group-matched case-control study. The findings of this study suggest that hepatitis virus (HBV, HCV) infection, drinking of alcohol, and dietary exposure to aflatoxin are likely etiologic agents of HCC in Henan, China.

[Comparison of partial sequencing of 5' non-coding region of seven HGV strains isolated from different areas in China]

OBJECTIVE

To explore the variation of Chinese hepatitis G virus (HGV) strains.

METHODS

HGV RNA was detected by reverse transcription nested polymerase chain reaction (RT-nPCR) with a designed primer derived from the 5' non-coding region of Chinese HGV strains. HGV cDNA was sequenced in seven samples with positive products by ABI prism 377 DNA automatic sequencer.

RESULTS

Homology of nucleotide sequence of the 5' non-coding region of HGV strains in seven Chinese strains was 88.26%, 85.92%, 88.26%, 85.45%, 86.85%, 85.92% and 88.26%, respectively, as compared with the African strains GBV-C (u 36380), and 92.02%, 86.85%, 86.67%, 89.02%, 89.67%, 89.67% and 91.55%, respectively, as compared with the strains isolated from the U.S. (u 44402). Homology of nucleotide sequence was 92.02% to 97.18% between HGV strains isolated in China.

CONCLUSION

Genotypes of Chinese HGV strains differ from those of GBV-C and HGV subtypes reported in the U.S.

A case-control study of hepatitis B and C virus infection as risk factors for hepatocellular carcinoma in Henan, China

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common cancers in the world and is particularly prevalent in China. China is also a hyperendemic area for hepatitis B virus (HBV) infection. Although a strong association between HBV infection and HCC has been established previously, the role of hepatitis C virus (HCV) infection and the interaction between HBV and HCV in the development of HCC has not been adequately explored. The major objective of this study is to determine the relationship between HBV or HCV infection and HCC by use of case-control study in Henan, China.

METHOD

In all, 152 HCC patients and 115 control patients were collected from four hospitals in Henan, China between January 1994 and October 1995. The demographic characteristics of the two groups were comparable. In further analysis, a 1:1 pair-matched case-control study was performed. Of 152 HCC patients, 113 were randomly selected to be pair-matched by sex and age (+/-5 years) to controls with non-hepatic disease. All the cases and controls were interviewed during hospitalization by two specially trained interviewers using a standard questionnaire. All sera were tested for HBV and HCV markers. Odds ratios (OR) and 95% CI for HCC risk factors were calculated by logistic regression model controlling for possible confounding factors such as sex and age. The multivariate analysis was done on the basis of the univariate analysis.

RESULTS

The results of this study indicated that the prevalence of hepatitis B surface antigen (HBsAg) and antibody to HCV (anti-HCV) were much higher in HCC patients (63.2% and 11.2% respectively) than in the control patients (5.2%, 3.5%). The difference between two groups was significant (P < 0.05). Risk factor analysis revealed that both HBV and HCV infection were important factors for HCC in Henan, China and HBV appeared to have a key role in the development of HCC. Odds ratios of HBsAg and HBV infection were 28.82 (95% CI: 11.18-78.78) and 31.22 (95% CI: 13.86-72.15), respectively. Moreover, the risk of developing HCC increased significantly and showed an additive effect when both viral markers of HBV and HCV infection were considered (OR = 42.85). Results from the 1:1 pair-matched case-control study also showed that HBV infection was an important risk factor for HCC, which was consistent with the results from the group-matched case-control study.

CONCLUSION

This is the first reported case-control study of HCC in Henan, China. This study provides further evidence that chronic HBV infection is strongly associated with the development of HCC among this population. Our results have demonstrated that HCV and HBV infection are independent and probably additive risk factors for HCC.

[Dynamics of anti-HEV ORF2, ORF3, IgM and IgG in serial sera of patients with hepatitis E and their clinical significance]

OBJECTIVE

To study the dynamics of anti-HEV ORF2, ORF3, IgM and IgG in serial sera of patients with hepatitis E.

METHODS

Anti-HEV was detected in serial sera of 52 patients, by an enzyme-linked immunosorbent assay (EIA) based on two synthetic peptides separated or combined from open reading frame (ORF) 2 and 3 of HEV genome.

RESULTS

Both anti-ORF2 and anti-ORF3 in serum were at the highest levels in early acute phase of the disease, and declined gradually with the course, especially anti-ORF3. The sensitivity of the EIA using both ORF2 and ORF3 peptides was higher than that of either alone. The positive rates of anti-HEV IgM and anti-HEV IgG were separately 71.1% (32/45) and 97.8% (44/45) within 15 days after onset, then decreased more dramatically in IgM than in IgG with the course.

CONCLUSION

Both ORF2 and ORF3 proteins should be used for the development of anti-HEV EIA kit. It seems to be more specific in anti-HEV IgM and more sensitive in anti-HEV IgG as a diagnostic marker of hepatitis E.

[The surgical treatment for the epiglottic cancer extended to the base of tongue]

26 cases of the epiglottic cancer extended to the base of the tongue were studied retrospectively. Among them, 14 were male and 12 female. The age varied from 43 to 62. Besides two cases who underwent total laryngectomy, the other twenty-four were treated with supraglottic horizontal partial laryngectomy or horizontovertical subtotal laryngectomy and resection of part of base of the tongue. 11 cases received bilateral radical neck dissection (RND) and 10 cases unilateral RND simultenously. The results showed twenty-four cases had resumed speaking ability, twenty had been decannulated and restored the laryngeal functions. The 5-year survival rate was 57.9% (12/19). It was concluded that transpharyngeal approach was reasonable for supraglottic horizontal partial laryngectomy associated with the resection of the base of the tongue.

[Clinical analysis of laser prostatectomy]

OBJECTIVE

To study the effect of laser prostatectomy for benign hypertrophy of prostate by transurethral noncontact laser ablation.

METHOD

204 patients with benign prostatic hyperplasia were treated by transurethral noncontact laser ablation.

RESULT

163 patients resumed urination in a week, and 37 in two weeks. Four patients were treated by open procedure. Patients were followed up for 14 months. Symptomatic scores (I-PSS) exceeded the middle rank in 90% patients and the maximum urinary flow rate was 89%.

CONCLUSION

It is an effective method for adjusting the strength, direction, range and frequency of laser to prevent bleeding, perforation and long-term urethral stricture.

[Genome shift of hepatitis E virus in Asia]

Dideoxy chain termination method was applied to sequence hepatitis E virus structure gene of Asia isolates, cDNA sequence and amino acid residues were determined. The results showed that among Asia countries: Indian, Burma, China, Pakistan and Kirghiz Republic, Hepatitis E virus genome shifted within the range of 5% and amino acid residues shifted within 1% compared with Mexico isolate. Asia Hepatitis E virus isolates have limited genome shift, which suggests recombinant Hepatitis E vaccine based on Asia HEV gene might protect all HEV infection in this area.

Assessment of body fat and lean in the elderly by measuring body carbon and oxygen: validation against hydrodensitometry

Based on the observation that the carbon-to-oxygen ratio (C/O) in tissue is a measure of fat content, we developed a model which correlates C/O to percent body fat. Carbon and oxygen mass and their ratio are measured in vivo by fast neutron inelastic scattering, using a miniature D-T neutron generator, at a radiation exposure of less than 0.06 mSv. We tested the validity of this model against hydrodensitometry with 19 healthy adult volunteers. The method was found to be accurate and insensitive to assumptions about the composition of lean tissue and, therefore, appropriate for studying the elderly and patients with catabolic conditions.

Use of fast neutrons for measuring muscle

Elemental Partition Analysis (EPA) is a new approach to body composition. A major element of the body is measured and then, by means of other measurements, is partitioned to the contributing body compartments. We developed a model for measuring total body muscle by applying the EPA method to total body phosphorus (TBP). We measure TBP (head excluded) by in vivo fast neutron activation analysis using the reaction 31P(n, alpha)28 Al. The main contributors to TBP are the bone and skeletal muscle. Adipose tissue and the liver contribute less than 3%. We use dual-energy X-ray absorptiometry (DXA) to evaluate the contribution of bone to TBP. Corrections are applied for the small contributions of the liver and adiopose tissue to TBP to derive muscle phosphorous. The technique requires high precision measurements for both TBP (+/- 2%) and DXA (+/- 1%). The total body radiation exposure for measuring human subjects is 0.60 mSv. We observed that nitrogen can also be measured by fast neutron activation analysis through the (n,2n) reaction, simultaneously with TBP.

[A cross-sectional study on HGV infection in a rural population]

OBJECTIVE

To determine the epidemiological characteristics and clinical significance of HGV infection, and to compare with HBV and HCV infections.

METHODS

Anti-HGV, HBsAg, anti-HBs, anti-HBc and anti-HCV were detected by enzyme-linked immunoassays (EIA). Anti-HGV positive sera were further tested for HGV RNA by a nested reverse transcription polymerase chain reaction (RT-nPCR).

RESULTS

The anti-HGV prevalence rate was 12.9%. It was relatively low in children under 10 years, and then increased with age and peaked in the group of 50-60 years of age (29.2%). The positive rate of HBsAg was 12.6%, and it quickly reached the highest (16.2%) in the 5-year old group. The prevalence rate of HBV infection was 64.9%, and increased to a high level in the group of 10 years of age, and maintained high up to 79.2% in the 50 years old group. The HCV infection rate was 15.3%. No anti-HCV positive cases were found in the group under 10 years of age. It was particularly high in the 20-40 years age group, and reached the peak in the group of 30 years old. No significant differences were found in the infection rates of HBV, HCV and HGV between male and female. HGV infection was associated with the history of blood donation, and the sexual transmission between couples. The anti-HGV positive rate of wives with anti-HGV positive husbands was 53.3%, significantly higher than that of those with anti-HGV negative husbands (7.8%). HGV coinfection with HBV or HCV had no influence on serum alanine aminotransferase (ALT). NO ALT elevation was found in the group with HGV infection alone.

CONCLUSIONS

The epidemiological characteristics of HGV infection are different from those of HBV and HCV. HGV is transmitted by blood and sex, and does not seem to cause liver damage.

A note on using only position equations for robotic hand/eye calibration

In two previous papers, we proposed an iterative algorithm for robotic hand/eye calibration. We stated that the iterative algorithm has two distinct advantages over traditional linear approaches: it is less sensitive to noise and it can calibrate the hand/eye matrix by using only relative sensor position measurements. In this correspondence, we point out that although the iterative algorithm does not require direct measurement of the sensor relative rotation, it still needs the user to provide the same amount of sensor orientation information. We also explain why the accuracy performance of the iterative algorithm was not improved by the inclusion of rotation equations.

[A study on viremia in patients with hepatitis E]

Hepatitis E virus RNA (HEV RNA) was detected in 531 serial serum specimens collected from 62 hospitalized patients with hepatitis E by reverse transcription-nested polymerase chain reaction (RT-nPCR) setting two pairs of primer from open reading frame 1 (ORF1) to understand the process of HEV infection more thoroughly. Results showed that 71 percent of the patients were positive for HEV RNA. Thirty-two of them with 288 serial serum specimens were followed up for the whole process, and 24 cases (75%) were positive for HEV RNA, positive rates declined with the course of the disease and serum HEV RNA lasted for 20.6 days in average. Serum HEV RNA was kept positive in 36 of the 44 patients (81.8%) at the time their serum alanine aminotransferase (ALT) and serum total bilirubin began to lower, and anti-HEV was detected in 39 of them (88.6%). Proportion of HEV viremia and length of it had no direct relationship with serum ALT and levels of total serum bilirubin and anti-HEV.

[Studies on GBV-C infection in blood donors in four provinces of China]

Plasma antibody against GBV-C (anti-GBV-C) and GBV-C RNA were detected with enzyme immunoassay (EIA) and reverse transcription nested polymerase chain reaction (RT-nPCR) in blood donors to study the prevalence of GBV-C infection in blood donors. Positivity of anti-GBV-C was 4.92 percent in 1,200 plasma donors (59/1,200), and that of GBV-C RNA was 64.41 percent in those with positive anti-GBV-C (38/59). Positivity of anti-GBV-C was 2.86 percent in 350 whole blood donors (10/350) and that of GBV-C RNA was 60.00 percent in those with positive anti-GBV-C (6/10). Positive rate of anti-GBV-C in those who donated blood for more than 10 years was higher than in control group. It suggests that infection with GBV-C was more often in plasma and blood donors. There were blood donors with positive GBV-C RNA but normal ALT activities and those both positive in GBV-C RNA and HCV RNA. It is urgent to detect the markers of GBV-C infection in blood donors as soon as possible.

The increased level of PDGF-A contributes to the increased proliferation induced by mechanical stimulation in osteoblastic cells

Mechanical stimulation can prompt healing of bone fractures. However, it is largely unknown how osteogenesis is promoted by mechanical stimulation. In this study, we found that mechanical strain-induced proliferation of osteoblastic cells (MC3T3-E1) accompanied increased levels of platelet-derived growth factor-A (PDGF-A) mRNA, determined by quantitative reverse transcription/polymerase chain reaction. In addition, neomycin and W-7, which blocked mechanical strain-induced proliferation of the osteoblast cells, also blocked mechanical stimulation-induced elevation of PDGF-A mRNA. Finally, an antibody against PDGF can inhibit physical stimulation-induced proliferation of MC3T3-E1 cells, suggesting that the increased MC3T3-E1 cells produced by mechanical stimulation at least partially depends on the increased activity of PDGF.

Total body potassium and body fat: relevance to aging

Understanding the mechanisms that govern sarcopenia (depletion of muscle mass with age) may suggest ways to preserve lean tissue and functional capacity, and to maintain quality of life in the elderly. We investigated the body-composition changes in normal aging in a cross-sectional study of 188 healthy volunteers aged 20-89 y, which examines the differences in body cell mass and fat as a function of age. In aging, the assumptions of indirect body-composition-measurement techniques, such as the "constant" hydration coefficient of lean body mass or the "constant" density of fat-free mass, may not hold. Therefore, we selected body-composition-measurement techniques that are not sensitive to assumptions about the composition of lean tissue. Cellular mass, lean body mass, and fat were assessed "directly" by total body potassium (TBK) measurements and neutron inelastic scattering. Our results show that TBK content declines at a rate of 7.20 +/- 1.00 mg K.kg body wt-1.y-1 for females (r = 0.601, P < or = 0.001) and 9.16 +/- 0.96 mg K.kg body wt-1.y-1 for males (r = 0.710, P < or = 0.001). Body fat measurements by neutron inelastic scattering have shown a significant increase of percentage body fat with age for female volunteers between the ages of 20 and 50 y and a continuous increase for male volunteers throughout adult life.

Amino-terminal epitopes are exposed when full-length open reading frame 2 of hepatitis E virus is expressed in Escherichia coli, but carboxy-terminal epitopes are masked

We constructed a panel of overlapping and non-overlapping fragments of cDNA derived from open reading frame 2 (ORF2) of hepatitis E virus (HEV) and fused to the gene encoding glutathione S-transferase (GST), from which proteins were expressed in Escherichia coli. IgG-specific immunoreactivity against each protein was measured by Western immunoblotting using sera from experimentally infected Rhesus macaques (Macaca mulatta) or from HEV-infected patients. Under these conditions, full-length ORF2 protein (GST-ORF2) was strongly reactive with acute-phase sera from either macaques or patients, but was poorly reactive with convalescent sera. Recombinant protein GST-ORF2.3, representing amino acids 1-110 of the 660 encoded by ORF2, demonstrated a pattern of reactivity largely indistinguishable from the full-length protein. Conversely, GST-ORF2.1, representing amino acids 394-660 of the ORF2 protein was strongly reactive with both acute- and convalescent-phase sera. Extension of GST-ORF2.1 towards the N-terminus led to a progressive loss of convalescent-phase reactivity, apparent with as few as 20 additional HEV-specific amino acids. Deletion of 40 or more amino acids from the N-terminus of ORF2.1 also led to reduced convalescent-phase reactivity, however a protein representing this "reactive" region, containing amino acids 394-473, was poorly reactive, suggesting that the convalescent-reactive epitopes are conformational. Expression of full-length ORF2 protein in E. coli therefore masks the convalescent-reactive epitopes within the C-terminal part of the protein, without affecting N-terminal, acute-reactive epitopes.

[Follow-up studies on hepatitis G infection in plasma donors with positive antibody against hepatitis C]

Antibodies against hepatitis G (anti-HGV) and HGV RNA were detected for frozen stored sera collected from 102 plasma donors and those subjects with positive anti-HGV and HGV RNA were followed-up for three years to study prevalence of HGV infection in them and their end-results. Anti-HGV was detected by enzyme immunoassay (EIA) with embedded antigen of synthetic peptide derived from different function regions of HGV. HGV RNA was detected by reverse transcription polymerase chain reaction (RT-PCR) with primers derived from NS3 region of HGV. Results showed that 19.61 percent (20/102) and 17.65 percent (18/102) of the plasma donors were positive for HGV RNA and anti-HGV, respectively, and 24.51 percent of them were infected with HGV (either positive for anti-HGV or HGV RNA), while only 0.94 percent (1/106) positive in the controls. It suggests that plasma donation is an important risk factor for HGV infection. Negative conversion rates of HGV RNA and anti-HGV during three-year follow-up were only 35.00 and 11.11 percent, respectively (7/20 and 2/18), which indicated a tendency of chronic carriage status in HGV infection.

Aerosol delivery to non-ventilated infants by metered dose inhaler: should a valved spacer be used?

In a randomized double-blind cross-over study on 20 spontaneously breathing, oxygen-dependent preterm infants who had received positive pressure ventilation for respiratory distress syndrome, we tested the hypothesis that the one-way non-rebreathing valves of aerosol spacer devices might impair rather than enhance the delivery of aerosols to small infants by metered dose inhalers (MDI). Ten infants were given 2 doses (200 micrograms/dose) of MDI albuterol through a neonatal Aerochamber 4 h apart. At random sequence, one dose was delivered with the non-rebreathing valve of the Aerochamber in place; for the other dose, the valve had been removed. The experiment was repeated on another ten infants using a different spacer device (Babyhaler) with or without its one-way inspiratory valve removed. During the first hour following aerosol administration, use of the non-valved spacers was associated with a significantly greater degree of tachycardia in both groups, and also lower transcutaneous carbon dioxide tension in the Aerochamber group. All infants showed a reduction in respiratory system resistance and an improvement in functional residual capacity following albuterol treatment. In both groups, maximum reduction in respiratory system resistance, recorded 30 min after aerosol delivery, was significantly greater following the use of the non-valved spacers (Aerochamber: 51.2 +/- 3.1% vs. 35.0 +/- 2.8%, P < 0.0001; Babyhaler: 38.8 +/- 2.3% vs. 19.2 +/- 1.4%, P < 0.0001) than following the use of the spacers with a valve. The findings provide indirect evidence supporting our hypothesis and suggest that when the MDI is used to deliver therapeutic aerosols to non-ventilated newborns or small infants, a spacer device without a non-rebreathing valve should be used.

Electrical stimulation induces the level of TGF-beta1 mRNA in osteoblastic cells by a mechanism involving calcium/calmodulin pathway

It is well-known that electrical stimulation can prompt healing of bone fractures. However, the mechanism involved is less clear. In this study, we found that capacitively coupled electric field-induced proliferation of osteoblastic cells (MC3T3-E1) accompanied increased levels of transforming growth factor-beta 1 (TGF-beta1) mRNA determined by quantitative reverse transcription/polymerase chain reaction. Previous reports have shown that verapamil and W-7, both of which block voltage gated calcium channels and inhibit the activation of cytosolic calmodulin, respectively, blocked capacitively coupled electric field-induced proliferation of the osteoblast cells. Interestingly, we found that verapamil and W-7 can also block capacitively coupled electric field-induced elevation of TGF-beta1 mRNA. This result suggested that electrical stimulation induces the level of TGF-beta1 mRNA in osteoblastic cells by a mechanism involving calcium/calmodulin pathway. The potential roles of TGF-beta in the electrical signal-induced osteogenesis was discussed.

Amino-terminal epitopes are exposed when full-length open reading frame 2 of hepatitis E virus is expressed in Escherichia coli, but carboxy-terminal epitopes are masked

We constructed a panel of overlapping and non-overlapping fragments of cDNA derived from open reading frame 2 (ORF2) of hepatitis E virus (HEV) and fused to the gene encoding glutathione S-transferase (GST), from which proteins were expressed in Escherichia coli. IgG-specific immunoreactivity against each protein was measured by Western immunoblotting using sera from experimentally infected Rhesus macaques (Macaca mulatta) or from HEV-infected patients. Under these conditions, full-length ORF2 protein (GST-ORF2) was strongly reactive with acute-phase sera from either macaques or patients, but was poorly reactive with convalescent sera. Recombinant protein GST-ORF2.3, representing amino acids 1-110 of the 660 encoded by ORF2, demonstrated a pattern of reactivity largely indistinguishable from the full-length protein. Conversely, GST-ORF2.1, representing amino acids 394-660 of the ORF2 protein was strongly reactive with both acute- and convalescent-phase sera. Extension of GST-ORF2.1 towards the N-terminus led to a progressive loss of convalescent-phase reactivity, apparent with as few as 20 additional HEV-specific amino acids. Deletion of 40 or more amino acids from the N-terminus of ORF2.1 also led to reduced convalescent-phase reactivity, however a protein representing this "reactive" region, containing amino acids 394-473, was poorly reactive, suggesting that the convalescent-reactive epitopes are conformational. Expression of full-length ORF2 protein in E. coli therefore masks the convalescent-reactive epitopes within the C-terminal part of the protein, without affecting N-terminal, acute-reactive epitopes.

[Partial nucleotide sequencing of hepatitis E virus isolated from sera of patients with acute sporadic hepatitis E in China]

28 hepatitis E virus (HEV) cDNA isolates were obtained from 41 sera of patients with acute sporadic hepatitis E (HE) in Shenzhen, Changchun and Hangzhou by a reverse transcription nested polymerase chain reaction (RT-nPCR) and 3 of the 28 RT-nPCR products of HEV cDNA ORF2 region were sequenced. The nucleotide homology of these three HEV isolates was 80.2%, 79.9% and 79.4%, respectively, as compared with the Maxico strain of HEV (M); 93.4%, 92.3% and 93.8% with the Burma epidemic strain of HEV(B) (Ep); 95.5%, 93.9% and 95.1% with the Burma sporadic strain of HEV(B) (Sp); 97.0%, 96.5% and 95.9% with the Xinjiang epidemic strain of HEV CH 1.1. It is demonstrated that these three isolates of HEV obtained from sera of acute sporadiic hepatitis E cases have a higher degree of homology with the Xinjiang strain of HEV CH 1.1 and the Burma strain of HEV(B). The data indicate that these three HEV isolates may belong to HEV(B) subtype, as the HEV CH 1.1 does.

[Partial nucleotide sequencing of 7 hepatitis E virus strains isolated from sera of patients with acute sporadic hepatitis E in China]

OBJECTIVE

To compare partial nucleotide and amino acid sequences between epidemic and sporadic hepatitis E viruses (HEV) in China and their relation to the frequency of hepatitis E (HE).

METHODS

A reverse transcription nested polymerase chain reaction (RT-nPCR) was used for the amplication of HEV open reading frame 2 (ORF2) cDNA from sera of patients with acute sporadic HE. The RT-nPCR products of HEV ORF2 cDNA were directly sequenced using a sequenase version 2.0 kit with the dideoxy sequencing method.

RESULTS

28 of 41 sera of patients with acute sporadic HE obtained from Shenzhen, Changchun, Hangzhou, Xian and Beijing by RT-nPCR were HEV ORF2 cDNA positive, and 7 of them were sequenced. The nucleotide homology of the seven HEV ORF2 cDNA was 78.9%-80.2%, as compared with the Mexico strain of HEV (M); 93.1%-95.1% with the Burma epidemic strain of HEV (B) (Ep); 92.3%-94.2% with the Burma sporadic strain of HEV (B) (Sp); 96.5%-98.9% with the Xinjiang epidemic strain of HEV CH 1.1; and 95.7%-100.0% between them.

CONCLUSIONS

The seven strains of HEV ORF2 cDNA isolated from sera of acute sporadic HE cases have a higher degree of homology with the HEV CH 1.1 and the HEV (B), and may belong to HEV (B) subtype, as the HEV CH1.1 does.

[Comparison of sequences of hepatitis B virus S gene fragment in eight cities of China]

Sequencing and comparative analysis of 52nd to 512th nucleotide of S gene in hepatitis B virus (HBV) were conducted in 43 cases of sero-positive and 52 cases of sero-negative HB from eight cities, including Changchun, Datong, Hangzhou, Shenzhen, Qingtao, Xi'an, Kunming and Lahsa, to study the relationship between focal variation of HBV S gene and seronegative HB. It was found that sequences of HBV S gene fragment in the same genotype were more conservative, most of its mutation happened randomly, and no insertion, deletion or null mutation occurred. There were three and five hypervariable nucleotide points in HBV isolated from two different HB groups with identical genotype and serotype (C genotype/adr serotype and C genotype/ayw1 serotype), respectively, and there were five hypervariable nucleotide points in HBV of D genotype/ayw1 serotype (five strains of sero-positive HBV) and D genotype/ayw3 serotype (ten strains of sero-negative HBV), respectively. It suggests that most cases of sero-negative HB may correlate with low level of HBV in their blood, and a small number of cases may be caused by HBV S gene mutation.

Heterogeneous nucleation of calcium phosphates on solid surfaces in aqueous solution

The heterogeneous nucleation of calcium phosphates on solid surfaces of poly(methyl methacrylate) (PMMA), poly-(tetrafluoroethylene-co-hexafluoropropylene) (FEP), silicone rubber, mica, and radiofrequency glow discharge (RFGD)-treated PMMA, FEP, and silicone rubber has been studied in solutions supersaturated with respect to hydroxyapatite. The surface properties of the substrates were characterized by contact angle measurements. For the RFGD-treated surfaces, the Lifshitz-Van der Waals surface tension component changes very little, but the Lewis acid-base surface tension parameters vary greatly depending upon the materials. With scanning electron microscopy, nucleation of calcium phosphates was observed only on the surfaces: mica, RFGD-treated PMMA and FEP, with relatively high values of the Lewis base surface tension parameter. The more hydrophobic surfaces having low Lewis acid-base surface tensions, untreated PMMA and FEP, silicone rubber, and even RFGD-treated silicone rubber showed no nucleation.

Mechanical strain-induced proliferation of osteoblastic cells parallels increased TGF-beta 1 mRNA

It is well known that mechanical stimulation can prompt healing of bone fractures. However, the mechanism involved is less clear. In this study, we found that a 0.17% cyclic, biaxial mechanical strain delivered at 1 Hz increased proliferation of MC3T3-E1 cells, a clonal osteoblastic cell line. Mechanical strain also increased the level of TGF-beta 1 mRNA determined by quantitative reverse transcription/ polymerase chain reaction. Previous reports have shown that neomycin and W-7, which are inhibitors in the inositol phosphate/calmodulin pathway, blocked mechanical strain-induced proliferation of the osteoblast cells. Interestingly, we found that neomycin and W-7 can also block mechanical stimulation-induced elevation of TGF-beta 1 mRNA. Finally, using an antibody which blocked the action of TGF-beta 1, we found that the increased MC3T3-E1 cell proliferation induced by mechanical strain did not depend on the action of TGF-beta 1.

A preliminary study on immune response to hepatitis E virus DNA vaccine in mice

OBJECTIVE

In order to elicit immune response to hepatitis E virus (HEV) with the method of direct injection of naked DNA.

METHODS

The gene encoding the structural protein of pORF3, a Chinese strain of HEV, was cloned into the eukaryotic expression plasmid pSVL. The resulted plasmid pSVL-HEV ORF3 was used as HEV DNA vaccine, to inoculate Balb/c mice intramuscularly with a dose of 100 micrograms. Mice injected with empty pSVL DNA served as control.

RESULTS

After 1-2 times inoculation, twelve of 16 mice inoculated with pSVL-HEV ORF3 had anti-HEV IgG seroconversion. pSVL-HEV ORF3 was still detectable in the muscle of the inoculated mice 18 days after the injection, by the method of PCR. None of the control group had a detectable level of anti-HEV IgG. It is also found that the humoral immune response to HEV induced by DNA vaccine could be boostered by HEV recombinant fusion protein.

CONCLUSION

Our present study demonstrated that nucleic acid vaccine is able to prime a specific humoral immune response to HEV in mice.

[Establishment and application of reverse transcription-nested polymerase chain reaction for detection of hepatitis E RNA in serum]

A reverse transcription-nested polymerase chain reaction (RT-nPCR) for detection of hepatitis E virus (HEV) RNA in serum was established using two pairs of oligonucleotide acid from open reading frame 1 and 2 (ORF1 and ORF2) of HEV cDNA as the inner and outer primers. Eleven serial sera from two rhesus monkeys experimentally infected with HEV were tested for HEV RNA with established RT-nPCR. HEV RNA became detectable in these two monkeys on the sixth day and the ninth day, respectively, and persisted up to the 17th and the 22nd day after infection, respectively. Twenty-eight serum specimens of the 41 patients with acute sporadic hepatitis E were HEV RNA positive (68.3%). Proportions of positive HEV RNA in patients sera collected one to ten days, 11 to 20 days and 21 to 34 days after their onset of the disease were 72.7% (16/22), 70.0% (7/10) and 55.5% (5/9), respectively. It suggests that viremia of HEV lasts a shorter period, and proportion of serum positive HEV RNA decreases with the course of the disease.

[Transurethral noncontact laser ablation of the large prostate]

42 cases of the large benign hypertrophy of the prostate were treated by transurethral noncontact laser ablation. The results of the patients followed up no less than six months and treatment were reported. The technique of the procedure and its related problems were described and our experience was presented. If we use the technique of the procedure skill fully, noncontact laser ablation of large benign hypertrophy of the prostate is safe and effective.

The impact of alteration of polyunsaturated fatty acid levels on C6-aldehyde formation of Arabidopsis thaliana leaves

C6-aldehydes are synthesized via lipoxygenase/hydroperoxide lyase action on polyunsaturated fatty acid (PUFA) substrates in plant leaves. The source pools and subcellular location of the processes are unknown. A close relationship is found between the composition of PUFA and the composition of C6-aldehydes. In the current study, this relationship was tested using the Arabidopsis PUFA mutant lines act1, fad2, fad3, fad5, fad6, and fad7. The results indicate that C6-aldehyde formation is influenced by the alteration of C18 PUFA levels. Mutants act1 and fad5, which are deficient in C16 unsaturated fatty acids, had wild-type levels of C6-aldehyde production. Mutants deficient in the chloroplast hexadecenoic acid/oleic acid desaturase (fad6) or hexadecadienoic acid/linoleic acid desaturase (fad7) had altered C6-aldehyde formation in a pattern similar to the changes in the PUFA. Mutations that impair phosphatidylcholine desaturase activity, such as fad2 and fad3, however, resulted in increased E-2-hexenal formation. The enzymes involved in C6-aldehyde production were partially characterized, including measurement of pH optima. The differences in C6-aldehyde formation among the fatty acid mutants of Arabidopsis appeared not to result from alteration of lipoxygenase/hydroperoxide lyase pathway enzymes. Investigation of the fatty acid composition in leaf phospholipids, glycolipids, and neutral lipids and analysis of the fatty acid composition of chloroplast and extrachloroplast lipids indicate that chloroplasts and glycolipids of chloroplasts may be the source or major source of C6-aldehyde formation in Arabidopsis leaves.

Interactions among Janus kinases and the prolactin (PRL) receptor in the regulation of a PRL response element

PRL regulates milk gene expression, at least in part, by activating JAK2 kinase and STAT5 (signal transducer and activator of transcription 5), initially termed mammary gland factor (MGF). These experiments were initiated to gain a better understanding of the mechanisms of transcriptional activation via PRL receptor (PRL-R) signaling. Binding of PRL to the recombinant pigeon PRL-R-activated transcription driven by a 2.8 kbp 5'-fragment of the rat beta-casein gene. PRL enhanced the expression of chimeric reporters containing the beta-casein PRL response element (PRE), but not the c-fos sis-inducible element, when the reporters were transfected into Chinese hamster ovary cells with the PRL-R. Wild type receptor, which contains a duplication of the entire extracellular ligand-binding domain, was only slightly more effective than a truncation mutant with a single extracellular domain. Transfection with either JAK1, JAK2, or JAK3 increased basal transcription through both the PRE and sis-inducible element. Coexpression of JAK2 with PRL-R resulted in amplification of the induction of the PRE by PRL, whereas JAKs 1 and 3 did not amplify the PRL effect. Overexpression of JAK2 mutants blocked PRE activation by PRL. Mutant JAK2 also interfered with PRE activation by JAK3 but did not affect JAK1's stimulatory effect.

[Treatment of the deformed ear and jaw]

Lengthening of the mandible by gradual distraction and ear reconstruction using tissue expanders were performed on nine young patients (6-11 years old) with unilateral hemifacial microsomia. The technique holds promise for reconstruction of ear and mandible at the same time. This is essentially a pilot clinical project. A late follow-up of these patients is necessary.

[Studies on peptide. XIX: Hepatitis C virus (HCV) immune selection]

HCV has characteristics of rapid variability. The amino terminus of E2/NS1 of HCV (amino acids sequence 384-414), which is hypervariable with respect to both nucleotide and amino acid sequence, has been termed the E2 HV domain or HVR1. The E2 HV domain appears to be a rapidly evolving region of the HCV genomes which may contain linear neutralizing epitopes and the E2 HV are under immune selection. For further studies of the immunogenicity on E2 HV of HCV, we selected three peptide fragments from the full length of E2 HV region sequence and synthesized them with SPPS method. The amino acid sequences are shown as following: P2: VDGDTHVTGGAQAKTTNR (381-398); P9: STHVTGAVQGHSIRGTTSLFTSGPAQKIQ (384-412); P10: RTYTSGGTAGHTTSGITSLFSPGASQKIQ (384-412). From the results of ELISA and anti-peptide Abs of rabbit sera, we conclude that there are anti-E2 HV Abs in immune host but they could not neutralize HCV, so these Abs were not reactive with all E2 HV epitopes that resulted in immune selection of escape mutants; the anti-E2 HV Abs, probably from the same genotype, contained some common structure in which E2 HV epitopes react with other anti-E2 HV Abs at 30%: the C-terminus of E2 HV region (398-412) caused the immune response to rabbits.

Transcriptional regulation of the apolipoprotein B-100 gene: identification of cis-acting elements in the first nontranslated exon of the human apolipoprotein B-100 gene

Apolipoprotein B-100, produced primarily in the human liver, is the sole protein component of low-density lipoprotein and serves as a ligand for the LDL receptor. Two cis-acting positive elements between -128 and -70 control hepatic cell-specific expression of the human apoB gene (H. K. Das, T. Leff, and J. L. Breslow, J. Biol. Chem. 263: 11452-11458, 1988). In this study, two apoB cis-acting elements (+20 to +40; +43 to +53) have been identified using DNase I footprint analysis. Through in vitro mutagenesis and transient transfection experiments in Hep G2 and HeLa cells, the element (+20 to +40) was observed to have a negative effect on transcription of the apoB gene. The element (+43 to +53) was found to have a strong positive effect on apoB gene transcription in Hep G2 cells and mild positive effect in HeLa cells. Therefore these two cis-acting elements mediate hepatic-cell specific expression of the apolipoprotein gene by interacting with trans-acting protein factors.

Erythropoietin-dependent inhibition of apoptosis is supported by carboxyl-truncated receptor forms and blocked by dominant-negative forms of Jak2

Apoptosis, or programmed cell death (PCD), recently has emerged as an important homeostatic mechanism within several hematopoietic lineages. This process is subject to both positive and negative modulation by cytokines and within the erythroid lineage is inhibited by interleukin-3, stem cell factor, and erythropoietin (Epo). Through the expression of carboxyl-truncated Epo receptor mutants in FDC-P1 cells, a receptor form possessing 80 membrane-proximal cytoplasmic residues is shown to efficiently mediate Epo-dependent inhibition of PCD. This is in contrast to previous studies that attributed this activity to a distal carboxyl-terminal receptor subdomain (and/or heterodimerization of wild type Epo receptors with a truncated non-functional receptor form). Epo-dependent inhibition of PCD also is shown to be blocked by ectopic expression of kinase-deficient dominant-negative forms of Jak2 (Jak2 delta VIII and Jak2-829), further underlining a role of this membrane-proximal subdomain of the Epo receptor in the inhibition of PCD. To our knowledge, this comprises the first direct evidence for an essential role for a Jak tyrosine kinase (Jak2) in this apoptotic response pathway.

Erythropoietin-induced recruitment of Shc via a receptor phosphotyrosine-independent, Jak2-associated pathway

Based on the recently implicated role of Shc as a signaling effector for type I cytokine receptors, factors which mediate the recruitment and phosphorylation of Shc in the erythropoietin receptor (EPOR) system have been studied. FDC-P1 cells stably expressing the wild type murine EPOR supported the EPO-induced association of Shc with Jak2 and its rapid tyrosine phosphorylation. However, this did not depend upon the presence of phosphotyrosine sites within the EPOR and was mediated by a mitogenically deficient receptor form (EPOR329) lacking cytoplasmic tyrosine residues. This was shown both by Western blotting of Shc and Jak2 co-immunoprecipitates and through the development of an in vitro assay for cytokine-induced Shc phosphorylation. The direct association of Shc with Jak2 also was observed and was shown to depend upon EPO-exposure and the SH2 subdomain of Shc. Together, these studies indicate that Jak2, in part, may mediate the EPO-induced phosphorylation of Shc.

Dominant negative effects of a carboxy-truncated Jak2 mutant on Epo-induced proliferation and Jak2 activation

Members of the Janus family of protein tyrosine kinases are emerging as primary, receptor-associated transducing factors among numerous cytokine systems. However, little is understood regarding mechanisms of recruitment of these kinases to receptor complexes and their ligand-dependent activation. To initially address these questions, we have assessed effects of ectopically expressing a carboxy-truncated form of Jak2 (Jak2-829) in Epo-responsive DAER cells. Expression of this truncation mutant at low levels efficiently inhibited both Epo-dependent activation of endogenous Jak2 and Epo-induced mitogenesis (10% to 39% of parental DAER cells). These results suggest that amino-terminal domains of Jak2 may mediate the assembly of Jak2/Epo receptor complexes and that integration of Jak2-829 into receptor complexes may effectively inhibit the activity of oligomeric Jak2/receptor assemblages.

Persistent and transient antibody responses to hepatitis E virus detected by western immunoblot using open reading frame 2 and 3 and glutathione S-transferase fusion proteins

Recombinant proteins containing amino acid sequences from open reading frame (ORF) 2 and ORF3 of a Chinese strain of hepatitis E virus (HEV) were constructed as fusions with glutathione S-transferase (GST). Stable fusion proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the proteins were transferred to nitrocellulose membranes, and the immobilized proteins were probed with sera from hepatitis E patients from various regions or from rhesus monkeys (Macaca mulatta) experimentally infected with the Chinese strain of HEV. Immunoglobulin G-class antibodies were detected with chemiluminescence and anti-human immunoglobulin G conjugated to horseradish peroxidase. Anti-ORF3 antibodies were detected in most patients and monkeys within 17 days of exposure, but this humoral response declined with time and was usually undetectable by approximately 100 days. Anti-ORF2.1 antibody was usually detected as early as anti-ORF3 but persisted in all animals and many patients, whereas reactivity to the larger GST-ORF2.2 fusion protein was more transient, even though all sequences present in GST-ORF2.1 are present in GST-ORF2.2. Rechallenge of these monkeys with HEV suggested that immunity to reinfection was incomplete, as levels of anti-ORF2.1 (but not anti-ORF2.2) were boosted after each rechallenge. The results demonstrate that the carboxy-terminal region of HEV ORF2 contains epitopes which are recognized by convalescent-phase antibody and are likely to be associated with limited immunity to infection, but these epitopes may be masked when larger portions of ORF2 are expressed as recombinant proteins.

Inhibition of erythropoietin-induced mitogenesis by a kinase-deficient form of Jak2

Receptors for a variety of hematopoietins, interferons alpha/beta and gamma, and growth hormone have recently been shown to mediate rapid, ligand-dependent activation of the Janus-type cytosolic protein-tyrosine kinases Jak1, Jak2, and/or tyk-2. This finding extends relatedness among class I and II cytokine receptors to a functional context and provides an initially satisfying mechanistic analogy to protein-tyrosine kinase-encoding receptors of the epidermal growth factor/platelet-derived growth factor/insulin family. Through the construction and expression of a kinase-deficient form of Jak2 (JK2 delta VIII) in interleukin-3 (IL-3)/erythropoietin (Epo)-dependent DAER cells, we have tested whether activation of Jak2 is required for induced mitogenesis via these class I cytokine receptors. Ectopic expression of JK2 delta VIII inhibited Epo- and IL-3-induced activation of endogenous wild-type Jak2, transiently attenuated IL-3-dependent growth, and essentially abrogated Epo-induced proliferation in this model system. These dominant-negative effects provide the first direct experimental evidence for an essential role for Janus kinase activation in mitogenesis and suggest that distinct effectors may mediate IL-3-induced versus Epo-induced pathways.

The extended box 2 subdomain of erythropoietin receptor is nonessential for Jak2 activation yet critical for efficient mitogenesis in FDC-ER cells

The development of erythroid progenitor cells depends upon exposure to the glycoprotein hormone, erythropoietin (EPO). Binding of EPO to its transmembrane receptor leads to the rapid tyrosine phosphorylation of several cellular targets including Shc, Raf-1, Gap120, the cloned EPO receptor (EPOR), pp100/97, and a M(r) 130,000 EPO-activated receptor-associated Janus protein tyrosine kinase, Jak2. A membrane-proximal cytosolic region of the EPOR recently has been shown to be essential for the activation of Jak2 and sufficient for EPO-induced mitogenesis. This cytosolic region includes 8-12 amino acid box 1 and box 2 subdomains, which are conserved in certain class I receptors as well as a more distal 10-40 amino acid subdomain (extended box 2 subdomain, ExBx2), which likewise is implicated in mitogenic signaling. Through the expression of EPOR carboxyl-terminal truncation mutants in FDC-P1 cells, we presently show that an EPOR form truncated within the ExBx2 domain efficiently activates Jak2, yet is deficient in mitogenesis. Efficient expression of this mutant receptor at the cell surface and its ability to activate Jak2 indicate that poor mitogenic activity does not result from aberrant transport or folding. Rather, failure of this mutant to support proliferation above nominal rates underlines an apparent role for the EPOR ExBx2 subdomain in the activation of a distinct primary mitogenic effector.

Rheumatoid cachexia: cytokine-driven hypermetabolism accompanying reduced body cell mass in chronic inflammation

The cytokines IL-1 beta and TNF-alpha cause cachexia and hypermetabolism in animal models, but their role in human inflammation remains controversial. The relationship between in vitro cytokine production and metabolism was examined in 23 adults with RA and 23 healthy control subjects matched on age, sex, race, and weight. Body composition was measured by multicompartmental analysis of body cell mass, water, fat, and bone mass. Resting energy expenditure (REE) was measured by indirect calorimetry. Cytokine production by PBMC was measured by radioimmunoassay. Usual energy intake, physical activity, disability scores, medication use, and other confounders were also measured. Body cell mass was 13% lower (P < 0.00001), REE was 12% higher (P < 0.008), and physical activity was much lower (P < 0.001) in subjects with RA. Production of TNF-alpha was higher in RA than controls, both before and after stimulation with endotoxin (P < 0.05), while production of IL-1 beta was higher with endotoxin stimulation (P < 0.01). In multivariate analysis, cytokine production was directly associated with REE (P < 0.001) in patients but not in controls. While energy and protein intake were similar in the two groups and exceeded the Recommended Dietary Allowances, energy intake in subjects with RA was inversely associated with IL-1 beta production (P < 0.005). In this study we conclude that: loss of body cell mass is common in RA; cytokine production in RA is associated with altered energy metabolism and intake, despite a theoretically adequate diet; and TNF-alpha and IL-1 beta modulate energy metabolism and body composition in RA.

Cholecystokinin gene expression in rat amygdaloid neurons: normal distribution and effect of morphine tolerance

Previous studies have shown that repeated opioid administration induces a tolerance to opioid, presumably due in part to an opioid-mediated compensatory increase in brain cholecystokinin (CCK) synthesis and/or release. In this study, in situ hybridization histochemistry was used to examine the effect of morphine tolerance on CCK gene expression in the amygdala of rat brains, by using a 35S-labeled synthetic oligonucleotide probe. CCK mRNA-positive neurons in normal rats were seen throughout the amygdaloid complex, with the most heavily labeled neurons in lateral, basal, and cortical nuclei, followed by the medial nucleus. Only a few labeled neurons were found in central and intercalated nuclei. The development of morphine tolerance in the rat was associated with increased hybridization signals for CCK mRNA in each subnucleus of the amygdala. Increases were seen in the numbers of positively labeled neurons and/or the numbers of hybridization grains per positively labeled neuron. Furthermore, differential patterns of increase in CCK mRNA in morphine tolerant rats occurred in different subnuclei of the amygdala, with the highest magnitude of increase in the cortical nucleus, followed in order by the medial, central, basal, intercalated and lateral nuclei. The present study demonstrated that repeated administration of morphine increased CCK gene expression in the amygdaloid complex, and suggested that the development of the tolerance to morphine analgesia is due, in part, to an increase in CCK activity in the amygdaloid complex. These findings substantiate the hypothesis that long-term administration of opioid may induce a compensatory increase in CCK synthesis and/or release, which then results in a progressive antagonism of opioid analgesia.

Association of the p85 regulatory subunit of phosphatidylinositol 3-kinase with an essential erythropoietin receptor subdomain

Using an active, HAI epitope-tagged form of the murine erythropoietin (EPO) receptor and via direct coimmunoprecipitation, the p85 regulatory subunit of phosphatidyl inositol-3 kinase (p85/PI3-K) is shown to associate with the EPO receptor in transfected FDC-P1 cell lines. Coimmunoprecipitation of p85 with epitope-tagged EPO receptors was observed initially in FDC-HER cells labeled metabolically with [32P]orthophosphate, and association of these factors was confirmed by Western analyses of receptor immunoprecipitates using p85 antiserum. Interestingly, this association occurred in the absence of ligand, and exposure of FDC-HER cells to EPO did not detectably affect levels of receptor-associated p85 or overall levels of p85 phosphorylation. However, EPO was observed to stimulated the rapid formation of phosphatidylinositol 32P-phosphate in FDC-HER and FDC-ER cells. Through baculovirus-mediated expression of epitope-tagged EPO receptor forms in SF9 cells, domains for p85 association were mapped. Analyses of receptor forms with cytosolic truncations and deletions delineated a candidate subdomain for p85 binding to an essential extended box-2 region (P329-E374; including a putative motif for SH2 binding, Y343LVL). These findings extend a mechanistic alignment between the EPO receptor and protein tyrosine kinase-encoding receptors that likewise activate PI3-K, and expand the importance of further defining pathways to PI3-K activation.