Inkjet printing of small molecules, biologics, and nanoparticles

During the last decades, inkjet printing has emerged as a novel technology and attracted the attention of the pharmaceutical industry, as a potential method for manufacturing personalized and customizable dosage forms to deliver drugs. Commonly, the desired drug is dissolved or dispersed within the ink and then dispensed in various dosage forms. Using this approach, several studies have been conducted to load hydrophilic or poorly water-soluble small molecules onto the surface of different solid substrates, including films, tablets, microneedles, and smart data-enriched edible pharmaceuticals, using two-dimensional and three-dimensional inkjet printing methods, with high dose accuracy and reproducibility. Furthermore, biological drugs, such as peptides, proteins, growth factors, and plasmids, have also been evaluated with positive results, eliciting the expected biological response; nonetheless, minor changes in the structure of these compounds with significant impaired activity cannot be dismissed. Another strategy using inkjet printing is to disperse drug-loaded nanoscale particles in the ink liquid, such as nanosuspension, nanocomplexes, or nanoparticles, which have been explored with promising results. Although these favorable outcomes, the proper selection of ink constituents and the inkjet printer, the correlation of printing cycles and effectively printed doses, the stability studies of drugs within the ink and the optimal analysis of samples before and after the printing process are the main challenges for inkjet printing, and therefore, this review analyzes these aspects to assess the body of current literature and help to guide future investigations on this field.

A comparison study of cerebral protection using Ginkgo biloba extract and Losartan on stroked rats

It has been well documented that oxidative stress is involved in stroke. Currently, many neuroprotective strategies have been targeted at molecules that are able to act as an oxidant to intervene with free-radical mediated apoptosis in the ischemic penumbra. In particular, natural products which contain antioxidant properties have undoubtedly efficacious for stroke treatment. In the current study, therapeutic effects of Ginkgo biloba extract (EGb) against cerebral protection in Wistar rats underwent middle cerebral artery occlusion (MCAO) was evaluated. A comparison study was conducted by using Losartan, an antihypertensive drug. Gene expression levels of pro-apoptotic genes (AT2 receptor, Fas, Bax and Bcl-xS) have shown to have significant reduction by EGb- and Losartan-treated groups as compared to vehicle group. Significant reduction of immunoreactivity of protein production of these genes, together with least nuclear green fluorescence observed in TUNEL, EGb, as an antioxidant drug, is concluded to have potent and promising therapeutic effect for stroke treatment.

The utility of AFLPs for supporting mitochondrial DNA phylogeographical analyses in the Taiwanese bamboo viper, Trimeresurus stejnegeri

An amplified fragment length polymorphism (AFLP) assay was performed on individuals representing discrete haplotypes from two genetically distinct mtDNA lineages of the bamboo viper, Trimeresurus stejnegeri (Schmidt), within Taiwan. AFLP (525 polymorphic markers from five primer pairs) and mtDNA genetic distances were highly correlated and an analysis of molecular variance, and a Bayesian approach similarly partitioned estimates of genetic similarity according to the mtDNA phylogeographical pattern. These results are discussed in relation to biogeographical hypotheses, comparative rates of mtDNA molecular evolution, and in the identification of evolutionary significant units of Taiwanese T. stejnegeri. In spite of the high degree of congruence between the genetic datasets, the AFLP phylogenetic analysis did not support the mtDNA tree, suggesting that no contemporary barriers to gene flow exist between individuals from the two mtDNA lineages.

Multiple causation of phylogeographical pattern as revealed by nested clade analysis of the bamboo viper (Trimeresurus stejnegeri) within Taiwan

In order to assess the utility of nested clade analysis, both standard phylogenetic algorithms and nested clade analysis were performed on a geographically widespread survey of mitochondrial DNA haplotypes of the bamboo viper, Trimeresurus stejnegeri, within Taiwan. Gross tree topologies were congruent for all analyses and indicated the presence of two geographically overlapping clades within Taiwan. The smaller lineage was restricted to the north and east coasts, whereas the larger lineage occupied all but the northern range of the species within Taiwan including the Pacific offshore populations of Green and Orchid Islands. The phylogeographical pattern supports the existence of at least one colonization event from the continent since the initial isolation of Taiwan from the mainland in the Pliocene. However, determining the exact number of colonization events was not possible due to the simultaneous vicariant forces of hypothesized continental landbridge connections and the occurrence of dramatic in situ orogenesis throughout the Pleistocene. Nested clade analysis provided multiple temporal and spatial population historical inferences that are not possible with standard analyses and therefore should become widely applied to future phylogeographical studies.

Extension of a pilot study: impact from the cytochrome P450 2D6 polymorphism on outcome and costs associated with severe mental illness

The influence of cytochrome P450 2D6 (CYP2D6) genetic variability was examined in psychiatric inpatients by evaluating adverse drug events (ADEs), hospital stays, and total costs over a 1-year period in an extension of a previously published brief report. One hundred consecutive psychiatric patients from Eastern State Hospital in Lexington, Kentucky, were genotyped for CYP2D6 expression. ADEs were evaluated by a neurologic rating scale, modified Udvalg for Kliniske Undersogelser Side Effect Rating Scale, or chart review. Information on total hospitalization days and total costs were gathered for a 1-year period. Forty-five percent of the patients received medications that were primarily dependent on the CYP2D6 enzyme for their elimination. When the analysis was restricted to just those patients in each group receiving medication heavily dependent on the CYP2D6 enzyme, the following were observed: (1) a trend toward greater numbers of ADEs from medications as one moved from the group with ultrarapid CYP2D6 activity (UM) to the group with absent CYP2D6 activity (PM); (2) the cost of treating patients with extremes in CYP2D6 activity (UM and PM) was on average $4,000 to $6,000 per year greater than the cost of treating patients in the efficient metabolizer (EM) and intermediate metabolizer (IM) groups; and (3) total duration of hospital stay was more pronounced for those in CYP2D6 PM group. Variance of hospital stays and costs calculated from these preliminary data suggests that 1,500 to 2,000 patients must be evaluated over at least a 1-year period to determine whether the CYP2D6 genetic variation significantly alters the duration of hospital stay and costs.

Blue- and green-absorbing visual pigments of Drosophila: ectopic expression and physiological characterization of the R8 photoreceptor cell-specific Rh5 and Rh6 rhodopsins

Color discrimination requires the input of different photoreceptor cells that are sensitive to different wavelengths of light. The Drosophila visual system contains multiple classes of photoreceptor cells that differ in anatomical location, synaptic connections, and spectral sensitivity. The Rh5 and Rh6 opsins are expressed in nonoverlapping sets of R8 cells and are the only Drosophila visual pigments that remain uncharacterized. In this study, we ectopically expressed Rh5 and Rh6 in the major class of photoreceptor cells (R1-R6) and show them to be biologically active in their new environment. The expression of either Rh5 or Rh6 in "blind" ninaE(17) mutant flies, which lack the gene encoding the visual pigment of the R1-R6 cells, fully rescues the light response. Electrophysiological analysis showed that the maximal spectral sensitivity of the R1-R6 cells is shifted to 437 or 508 nm when Rh5 or Rh6, respectively, is expressed in these cells. These spectral sensitivities are in excellent agreement with intracellular recordings of the R8p and R8y cells measured in Calliphora and Musca. Spectrophotometric analyses of Rh5 and Rh6 in vivo by microspectrophotometry, and of detergent-extracted pigments in vitro, showed that Rh5 is reversibly photoconverted to a stable metarhodopsin (lambda(max) = 494 nm), whereas Rh6 appears to be photoconverted to a metarhodopsin (lambda(max) = 468 nm) that is less thermally stable. Phylogenetically, Rh5 belongs to a group of short-wavelength-absorbing invertebrate visual pigments, whereas Rh6 is related to a group of long-wavelength-absorbing pigments and is the first member of this class to be functionally characterized.

Securinine induced apoptosis in human leukemia HL-60 cells

AIM

To study whether securinine might induce apoptosis in human leukemia HL-60 cells.

METHODS

Inhibition of proliferation was measured using MTT assay. The amount of apoptotic cells was measured by flow cytometry. DNA fragmentation was visualized by DNA agarose gel electrophoresis and the cellular changes were observed by electron microscope.

RESULTS

Securinine 5-80 mg.L-1 elicited typical apoptosis morphological changes and DNA fragmentation in a concentration-dependent manner in HL-60 cells. Securinine inhibited HL-60 cell proliferation in a time- and concentration-dependent manner. The IC50 and 95% confidence limits were 27 (15-47) mg.L-1 after 12-h treatment with securinine.

CONCLUSION

Securinine induced apoptosis in HL-60 cells.

Patterning of the R7 and R8 photoreceptor cells of Drosophila: evidence for induced and default cell-fate specification

Opsin gene expression in the R7 and R8 photoreceptor cells of the Drosophila compound eye is highly coordinated. We have found that the R8 cell specific Rh5 and Rh6 opsins are expressed in non-overlapping sets of R8 cells, in a precise pairwise fashion with Rh3 and Rh4 in the R7 cells of individual ommatidia. Removal of the R7 cells in sevenless, boss or sina mutants, disrupts Rh5 expression and dramatically increases the number of Rh6-expressing R8 cells. This suggests that the expression of Rh5 may be induced by an Rh3-expressing R7 cell, whereas Rh6 expression is most likely a default state of the R8 cell. We found that the paired expression of opsin genes in the R7 and R8 cells occurs in a sevenless and boss independent manner. Furthermore, we found that the generation of both Rh3- and Rh4-expressing R7 cells can occur in the absence of an R8 cell. These results suggest that the specification of opsin expression in the R7 cells may occur autonomously, whereas the R7 photoreceptor cell may be responsible for regulating a binary developmental switch between induced and default cell-fates in the R8 cell.

Elemene induces apoptosis and regulates expression of bcl-2 protein in human leukemia K562 cells

AIM

To study the antitumor action of elemene (Ele) and its mechanism.

METHODS

Inhibition of proliferation was measured with a colorimetric 3-[4,5-dimethyl thiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Morphological assessment of apoptosis was performed with fluorescence microscope. DNA fragmentation was assessed by agarose gel electrophoresis and flow cytometry. The levels of bcl-2 protein was measured with flow cytometry.

RESULTS

Exposure of exponentially growing K562 cells to Ele 65-520 mumol. L-1 for 48 h resulted in growth arrest. The values of IC50 and 95% confidence limits were 220 (152-319) mumol.L-1. After treatment of K562 cells with Ele 130 mumol.L-1, marked morphological changes including "Apo bodies" reduction in volume were observed with fluorescence microscope. Agarose gel electrophoresis of DNA from cells treated with Ele for 48 h revealed "ladder" pattern. The levels of bcl-2 protein in K562 cells treated with Ele for 48 h were obviously decreased.

CONCLUSION

Ele induces apoptosis of K562 cells, which is related with the down-regulation of bcl-2 protein in K562 cells.

Pilot study of the cytochrome P450-2D6 genotype in a psychiatric state hospital

OBJECTIVE

The authors conducted a pilot study to develop preliminary data on the frequency of cytochrome P450-2D6 (CYP2D6) genotypes in state psychiatric hospital patients and to establish population sizes needed to determine potential clinical relevance in therapeutic outcome.

METHOD

One hundred consecutive inpatients at Eastern State Hospital in Kentucky who provided informed consent were genotyped at the CYP2D6 locus during their hospital stay.

RESULTS

Twelve of the patients were CYP2D6 deficient, and four carried the *1Xn or *2Xn allele associated with ultrarapid metabolism; all of these patients were Caucasian (N=87). The rate of deficiency in CYP2D6 expression in these Caucasian state psychiatric hospital patients (14%) was twice that of the U.S. population (7%). The patients with CYP2D6 deficiency also appeared more likely to experience side effects in response to CYP2D6 medications.

CONCLUSIONS

This study, limited by a small number of subjects, suggests that one-fifth of Caucasians admitted to a state hospital in Kentucky had genotypes associated with extremes in CYP2D6 activity that may have affected their response to CYP2D6 medications.

A thyroid hormone receptor coactivator negatively regulated by the retinoblastoma protein

The retinoblastoma protein (Rb) plays a critical role in cell proliferation, differentiation, and development. To decipher the mechanism of Rb function at the molecular level, we have systematically characterized a number of Rb-interacting proteins, among which is the clone C5 described here, which encodes a protein of 1,978 amino acids with an estimated molecular mass of 230 kDa. The corresponding gene was assigned to chromosome 14q31, the same region where genetic alterations have been associated with several abnormalities of thyroid hormone response. The protein uses two distinct regions to bind Rb and thyroid hormone receptor (TR), respectively, and thus was named Trip230. Trip230 binds to Rb independently of thyroid hormone while it forms a complex with TR in a thyroid hormone-dependent manner. Ectopic expression of the protein Trip230 in cells, but not a mutant form that does not bind to TR, enhances specifically TR-dependent transcriptional activity. Coexpression of wild-type Rb, but not mutant Rb that fails to bind to Trip230, inhibits such activity. These results not only identify a coactivator molecule that modulates TR activity, but also uncover a role for Rb in a pathway that responds to thyroid hormone.

Inhibition of aldose reductase and sorbitol accumulation by astilbin and taxifolin dihydroflavonols in Engelhardtia chrysolepis

Dihydroflavonol taxifolin and its glycoside, astilbin, from Engelhardtia chrysolepis inhibited rat lens and recombinant human aldose reductase. Taxifolin also inhibited sorbitol accumulation in human red blood cells. Furthermore, this dihydroflavonol aglycone maintained the clarity of rat lens incubated with a high concentration of glucose. These dihydroflavonols may be effective for preventing osmotic stress in hyperglycemia.

Identification of a novel Drosophila opsin reveals specific patterning of the R7 and R8 photoreceptor cells

The function of the compound eye is dependent upon a developmental program that specifies different cell fates and directs the expression of spectrally distinct opsins in different photoreceptor cells. Rh5 is a novel Drosophila opsin gene that encodes a biologically active visual pigment that is expressed in a subset of R8 photoreceptor cells. Rh5 expression in the R8 cell of an individual ommatidium is strictly coordinated with the expression of Rh3, in the overlying R7 cell. In sevenless mutant files, which lack R7 photoreceptor cells, the expression of the Rh5 protein in R8 cells is disrupted, providing evidence for a specific developmental signal between the R7 and R8 cells that is responsible for the paired expression of opsin genes.

The cytochrome P450 2D6 (CYP2D6) enzyme polymorphism: screening costs and influence on clinical outcomes in psychiatry

OBJECTIVES

This study examined factors that affect cost, reliability, and the value of determining the cytochrome P450 2D6 (CYP2D6) polymorphism in clinical practice.

STUDY DESIGN

The method of deoxyribonucleic acid isolation, sample preparation, oligonucleotide primers, and polymerase chain reaction procedures were scrutinized for their effect on CYP2D6 genotyping efforts. The determination of the CYP2D6 A, B, D, E, and T alleles was used to identify the deficiency in CYP2D6 expression in 161 individuals phenotyped for CYP2D6 activity with dextromethorphan. The CYP2D6 genotype was assessed in 74 outpatients who had received diagnoses of depression. Eighteen of these patients were screened because of an adverse response to a tricyclic or antidepressant known or suspected to be a CYP2D6 substrate.

RESULTS

The CYP2D6 A, B, C, D, E, and T alleles could be detected in 13 hours at a cost of $84 per sample by judicious selection of conditions and procedures. The genotype provided an accurate predictor of CYP2D6 expression in all 134 subjects who expressed the enzyme and in all 27 unrelated individuals phenotyped as deficient in CYP2D6 activity. In the patient group that experienced adverse effects, 44% of all CYP2D6 gene copies contained the A, B, D, E, or T allele(s) associated with inactive CYP2D6 expression. This was more than twice the rate for the occurrence of mutant alleles in the other 56 psychiatric patients (21%) and in 80 random subjects from the general population (20%; p < 0.05).

CONCLUSIONS

Screening psychiatric patients for CYP2D6 expression may distinguish metabolic-based therapeutic problems from drug sensitivity caused by other mechanisms.

Inhibition of aldose reductase by dihydroflavonols in Engelhardtia chrysolepis and effects on other enzymes

Astilbin and neoastilbin, dihydroflavonol rhamnosides from Engelhardtia chrysolepis, showed potent inhibition of lens aldose reductase. Kinetic analysis showed astilbin exhibited uncompetitive inhibition against both dl-glyceraldehyde and NADPH. These taxifolin glycosides were selective inhibitors of aldose reductase with no inhibition of NADH oxidase.

Protection against oxidative damage by dihydroflavonols in Engelhardtia chrysolepis

Dihydroflavonol taxifolin and its glycoside, astilbin, from Engelhardtia chrysolepis were evaluated as antioxidants and radical scavengers. These dihydroflavonols inhibited superoxide anion production in the xanthine/xanthine oxidase system. Microsomal lipid peroxidation induced by NADPH-cytochrome P-450 reductase was also inhibited by these flavonoids. Mitochondrial lipid peroxidation was inhibited only by the aglycon. Taxifolin protected peroxy radical-damaged mitochondria with no effect on enzyme activity. Furthermore, taxifolin and astilbin protected red cells against oxidative hemolysis. These dihydroflavonols were found to be effective for protecting subcellular systems and red blood cells against oxidative stress in vitro.

Differentiation of Salmonella typhi strains by ribosomal RNA gene restriction patterns

Owing to the limited value of phage typing to determine the epidemiological association of Salmonella typhi (S. typhi) strains isolated from the source of typhoid fever, we analyzed ribosomal RNA (rRNA) gene restriction patterns to differentiate the independently isolated strains of identical phage type. The data showed that the restriction patterns of PstI was most polymorphic among four enzymes (BamHI, EcoRI, PstI, and SmaI) used, which revealed 13 types among 25 strains belonged to 4 phage types, 1 untypable and 2 not-determined strains. Total 25 strains of S. typhi were divided into 15 combination types by the rRNA restriction patterns with three enzymes (BamHI, PstI, and SmaI).

Genotype distribution of hepatitis C virus infection in Taiwan

To investigate the prevalence of genotype distribution of hepatitis C virus (HCV) infection in Taiwan, genotypes were identified in 122 (36 anti-HCV-positive blood donors, 44 anti-HCV-positive aborigines, 28 hemodialysis patients, and 14 patients with chronic liver diseases) of 280 subjects, using polymerase chain reaction by Okamoto's type-specific primer method. Type II was the dominant (66.7%) type among anti-HCV-positive blood donors, followed by type III and type IV with the same percentages (16.7%), while none of type I was detected. The prevalence of genotype distribution were 75.0%, 81.1%, and 64.3% for type II, 4.6%, 17.9%, and 21.4% for type III, 13.6%, 0%, and 7.1% for type IV, for the aborigines, hemodialysis, and chronic liver diseases groups, respectively. Four subjects revealed mixed infections by two different genotypes: two cases of II and III; and each one case of II and IV, and III and IV. Diverse genotype distributions in two hemodialysis groups disclose the existence of obvious regional differences even within a region. The results reveal the highest prevalence of type II as in Japan. However, there is a higher prevalence rate of type IV than in Japan.

Comparison of hepatitis C virus strains obtained from hemodialysis patients

To understand what genotypes of hepatitis C virus (HCV) exist in Taiwan, we chose the non-structure 5 (NS5) region of the HCV genome for the target area of reverse transcription-polymerase chain reaction (RT-PCR) to detect HCV RNA from sera of hemodialysis patients. Of 39 serum samples which were positive for the HCV antibody among 87 samples from hemodialysis patients, 12 (antibody against HCV core protein, OD > 2) were examined by the RT-PCR. The plasmid pUC19 was used to clone HCV cDNAs in the NS5 region (401 bp) derived from 11 serum samples which were positive for HCV RNA. Sequence analyses of individual clone of these 11 amplified cDNA fragments were performed. Dr. Cha's classification (16) suggested that two genotypes of HCV were found in these serum samples; type II (2/18.2%) and type III (9/81.8%). Our study indicates also that NS5 is an adequate target region to differentiate HCV strains derived from different patients in the same hospital. The analysis of the amplified cDNA in the NS5 region of the HCV genome will therefore provide suitable information to perform a molecular epidemiological study on the transmission routes of this important virus infection.

Sequence analysis of nucleocapsid and partial envelope genes of the hepatitis C virus derived from an aboriginal asymptomatic carrier

Two overlapping cDNA fragments of the 5'-terminal region of the hepatitis C virus (named as HCV-B) were cloned by reverse transcription-polymerase chain reaction (RT-PCR). The consensus nucleotide sequence of the 1101 nucleotide length was constructed from the sequences of at least three independent clones of each one of these two amplified overlapping HCV cDNA fragments. By comparison with other HCV strains isolated from different countries, the 5' non-coding region was almost identical, with only 1 difference in 90 nucleotides, and the homology of the putative nucleocapsid gene was found to be quite conservative, with a similarity of 90-96% and 96-97% at the nucleotide and amino acid levels, respectively. The homology of the down-stream region which encodes a putative envelope protein showed a low degree of identities (71.5% and 76.7% compared with American HCV-1 strain) at the levels of nucleotide and amino acid. On the other hand, it was similar to the Taiwanese HCV-T strain and the Japanese major J1 strain; the homology was about 93% at both levels of nucleotide and amino acid. This finding led to a conclusion that the HCV-B strain is closely related to the major HCV genotypes as HCV-J1 and HCV-T, isolated in Asian area.

Silent mother-to-child transmission of hepatitis C virus through two generations determined by comparative nucleotide sequence analysis of the viral cDNA

To investigate the routes of transmission of hepatitis C virus (HCV), a family in which HCV was considered to be transmitted from mother to child through two generations was studied. By the polymerase chain reaction method, HCV cDNA was isolated from the serum of a female baby with self-limited hepatitis C. HCV cDNA was also obtained from her mother and grandmother, who are healthy carriers of HCV, as well as from her uncle suffering from chronic persistent hepatitis C. The nucleotide sequence of the HCV cDNA fragment obtained from the baby was identical to that of the mother and was much closer to those of the grandmother and the uncle than to HCV cDNA isolates previously obtained from other Japanese patients or carriers. These results indicate the presence of mother-to-child transmission of HCV and suggest a role of this transmission route in establishing HCV carriers and maintaining a high incidence of HCV infection.

High prevalence of hepatitis C virus infection in aborigines in Taiwan

In Taiwan, the epidemiological status of HCV infection is similar to those observed in other areas of the world, with 1.0% prevalence among adult volunteer blood donors and high prevalences among the high risk groups, by the detection of anti-HCV with synthetic peptide antigens. However, unusually high prevalences, 35.1%, 15.8% and 14.2%, were observed among adult populations in three of the five aboriginal communities. No difference in sex specificity was noted. In 37 (75.0%) of the 48 anti-HCV-positive cases, HCV-RNA was detected by reverse transcription polymerase chain reaction (RT-PCR) assay. None of such particular risk factors as tattooing, sexual promiscuity, operation, blood transfusion, nor intravenous drug abuse could be accounted for this high prevalence of HCV infection. No helpful supporting evidence for ethnic specificity was noted, either. Although a possible sexual transmission between spouses was observed, it is unlikely to be the main cause of the high prevalence in these aboriginal communities. We conclude that the unusually high prevalence of HCV infection observed in some aboriginal communities in Taiwan could be ascribed to poor anti-septic medical practice derived from insufficiency of medical personnel and facilities in these communities as compared with the other regions in Taiwan at the time before twenty years ago.

Discrimination of hepatitis C virus in liver tissues from different patients with hepatocellular carcinomas by direct nucleotide sequencing of amplified cDNA of the viral genome

We investigated the presence of the hepatitis C virus (HCV) genome in liver tissues of eight different patients with hepatocellular carcinoma by using the reverse transcriptase polymerase chain reaction (PCR) method. RNA was extracted separately from cancerous and peripheral noncancerous portions of the liver tissues of each patient. For reverse transcriptase PCR, we used sets of primers derived either from nonstructural region 3 (the NS3 region) or from the nucleocapsid-envelope (C/E) region of the HCV genome. The nucleotide sequences of the amplimers were directly determined without subcloning. Of 16 samples tested, cDNA of the HCV genome was detected in 2 cancerous tissues and in 4 noncancerous tissues by either pair of primers. Nucleotide sequences of HCV cDNA fragments amplified from cancerous and peripheral noncancerous tissues from the same patients were identical. However, 4.4 to 6.3% and 7.5 to 11.3% sequence variation was observed in NS3 and C/E regions, respectively, among cDNA fragments from different patients. The result indicated that the HCV genome detected in a given patient is distinguishable from that in others by a simple direct nucleotide sequencing of the reverse transcriptase PCR products.

Molecular cloning of cDNA of hepatitis C virus (HCV) genome from a healthy carrier in an aboriginal community in Taiwan with high prevalence of HCV infection

We analyzed hepatitis C virus (HCV) obtained from a healthy HCV carrier in an aboriginal community with high prevalence of HCV infection. By use of random primers and specific oligonucleotide primers, a cDNA fragment of putative non-structural 3 (NS3) region of the HCV genome was cloned by reverse transcription-polymerase chain reaction (RT-PCR) using RNA extracted from a serum sample of a healthy HCV carrier in Taur-Yuan village. The nucleotide and deduced amino acid sequences from the 583 nucleotides long cDNA were compared with those of equivalent region of HCV of other previously reported clones: [J1, HCV-J (regarded as major type of HCV in Japan) and US prototype]. They had 93.7% (546/583), 93.1% (543/583) and 80.4% (469/583) homology at the nucleotide level and 96.9% (188/194), 96.9% (188/194) and 91.8% (178/194) homology at the amino acid level, respectively. These results showed that HCV prevalent in an aboriginal community in Taiwan is more similar to Japanese type than to the US prototype.

Antibody against Epstein-Barr virus DNA polymerase activity in sera of patients with nasopharyngeal carcinoma

A salt-dependent DNA polymerase activity was demonstrated in the culture of an EBV-producing, lymphoblastoid cell line (NPC-204 cells) treated with 5-iodo-2'-deoxyuridine (IUdR). There was a high frequency of levels of antibody to this enzyme in sera of patients with nasopharyngeal carcinoma (NPC). In contrast, sera from healthy subjects had little or no neutralizing activity. The high antibody level appeared as early as stage 1 of the disease in many NPC patients. The levels of the antibody increased with the progression of the disease and declined in treated patients. The results strongly suggest that tests measuring serum antibody against EBV DNA polymerase activity can be used for early diagnosis and prognosis of NPC.