Allele typing of human TNFA 5'-flanking region using polymerase chain reaction-preferential homoduplex formation assay (PCR-PHFA): linkage disequilibrium with HLA class I and class II genes in Japanese

Tumor necrosis factor alpha plays a substantial role in a number of conditions such as inflammation, autoimmunity, insulin resistance and sleep. Three new single nucleotide polymorphisms, -1,031 T/C, -863 C/A and -857 T/C, were recently identified in the upstream 5'-flanking region of TNFA in the Japanese population. In the present study, we developed polymerase chain reaction (PCR)-preferential homoduplex formation assay for the single-step allele typing of TNFA, and determined the genotypes of 271 healthy unrelated Japanese individuals. Four haplotypes, -1,031/-863/-857 TCC, TCT, CAC and CCC, were found to constitute the majority, if not all, of the TNFA alleles of healthy Japanese population. These alleles were designated as TNFA-U01, -U02 -U03 and -U04, respectively, in the order of frequency. Based on HLA-A, -B and -DRB1 genotypes together with TNFA genotypes, multi-locus haplotypes were analyzed. Significant positive associations were observed between TNFA-U01 and A*3303, B*5201, B*4403, B*4601, B*0702, DRB1*1502, DRB1*0101, DRB1*1302, between TNFA-U02 and B*5401, B*3501, DRB1*0405, DRB1*0407, between TNFA-U03 and B*4006, B*4002, DRB1*0803, DRB1*0802, DRB1*0403, DRB1*0901, and between TNFA-U04 and B*4801. Four-locus haplotype estimation revealed that A*3303-B*4403-TNFA-U01-DRB1*1302, A*2402-B*5201-TNFA-U01-DRB1*1502 and A*2402-B*5401-TNFA-U02-DRB1*0405 constitute major extended haplotypes in Japanese. Interestingly, TNFA alleles previously shown to have a higher promoter activity (U02, U03) were found to form haplotypes with certain DRB1 alleles associated with T helper 1 (Th1)-dominant diseases such as rheumatoid arthritis, insulin dependent diabetes mellitus and Crohn's disease in Japanese. In contrast, TNFA allele with a low promoter activity (U01) is in linkage disequilibrium with the DRB1 alleles associated with T helper 2 (Th2)-dominant diseases such as atopic dermatitis and ulcerative colitis. These observations raise the possibility that TNFA upstream promoter region polymorphisms contribute to some of the HLA-disease associations.

Adaptation of guinea-pig superficial masseter muscle to an increase in occlusal vertical dimension

To study the effect of increased occlusal vertical dimension on the fibre phenotypes of the superficial masseter muscle, the composition of myosin heavy-chains (MHC), myosin light-chains (MLC) and tropomyosin was investigated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and two-dimensional gel electrophoresis in conjunction with densitometric analysis in normal (control) and bite-opened (5.7 mm increase in the vertical dimension for 1 week) guinea-pigs. The superficial masseter contained two fast-type MHC isoforms, II-1 and II-2, in both the bite-opened and control groups; their relative content (mean+/-SD, n = 7) was 47.8+/-2.9% and 52.2+/-2.9%, in the bite-opened and 44.4+/-3.0% and 55.6+3.0% in control preparations, indicating no significant (p>0.05) changes in MHC composition in association with the bite opening. On the other hand, significant differences in MLC and tropomyosin composition were found between the two preparations. Although the MLC consisted of three components, LC1f, LC2f and LC3f, in both preparations, their relative content (mean+/-SD, n = 7) was 37.1+/-2.4%, 49.6+/-1.6% and 13.2+/-3.2%, respectively, in the bite-opened and 28.1+/-3.1%, 50.9+/-1.6% and 21.0+/-3.5% in the control preparations, indicating that the bite opening induced a significant (p < 0.0001) increase in the relative content of LC1f at the expense of that of LC3f. Although the tropomyosin consisted of two components, TM-alpha and TM-beta, in both preparations, their relative content (mean+/-SD, n = 7) was 91.8%+/-1.9% and 8.2+/-1.9%, respectively, in the bite-opened and 95.9+/-0.7% and 4.1+/-0.7% in the control preparations, showing a significant (p < 0.001) increase in the relative content of TM-beta in relation to the bite opening. These results indicate that in guinea-pigs an increase in occlusal vertical dimension for 1 week changes the composition of MLC and tropomyosin, with no significant change in MHC, in the masseter muscle. These changes might be required to meet altered functional demands.

[Changes in Bruch's membrane in experimental hypercholesteremia in rats]

PURPOSE

We investigated the effect of high cholesterol diet for the aging changes in Bruch's membrane of rats.

METHODS

After feeding a 4% cholesterol diet for 15 weeks to three young rats 3 months old and four aged rats 23 months old, we observed the morphological changes of Bruch's membrane by electron microscopy, and made a comparison with rats fed an ordinary diet.

RESULTS

In one young rat fed a high-cholesterol diet, the endothelial basement membrane of the choriocapillaris formed multiple folds separated from the plasma membrane of the endothelium and showed lamellar thickening and crack in some areas. The elastic fiber layer in Bruch's membrane disappeared partly and some new microfibrils appeared. In one aged rat fed a high-cholesterol diet, the endothelial basement membrane of the choriocapillaris showed more lamellar thickening with lumps in some parts. Compared with rats fed an ordinary diet, rats fed a high-cholesterol diet showed thickening of the basement membrane and the changes were more severe.

CONCLUSIONS

Our data indicated that high-cholesterol diet might promote age-related changes of Bruch's membrane.

[Age-related changes in Bruch's membrane in rats]

PURPOSE

We investigated rats were worth the experimental animal on the aging changes in Bruch's membrane.

METHODS

We did an ultramicromorphological study on the aging changes in Bruch's membrane, in male Sprauge-Dawley rats at 1,6,12 and 27 months after their birth.

RESULTS

With the aging, the basement membranes on both sides of Bruch's membrane have become thick. At 6 months of age, the basement membranes of the endothelial cells of the choriocapillaris were found to be multilayered and cracked and pseudopodia of the endothelium were also observed toward the retinal pigment epithelium. At 12 months of age, we found vacuoles in the basal portion of the retinal pigment epithelium, as well as fibrillae and a part of the process of a cell in the outer collagenous zone correspond with the portion of the multilayered and cracked basement membranes of the endothelial cells of the choriocapillaris. At the age of 27 months, the basement membranes were thicker and a basal laminar deposit was seen. Prominent changes such as disappearance of the elastic fibers and increase of the collagenous fibers and fibrillae were also seen in some portions.

CONCLUSIONS

Thus, the aging changes in Bruch's membrane of rats were remarkably reinforced in accordance with the age, it were appeared these rats were worth the experimental animal.

A novel conception for liver preservation at a temperature just above freezing point

BACKGROUND

It is generally accepted that 0 to 4 degreesC is a suitable temperature for organ preservation. The reason for this is based on the premise that at temperatures below 0 degreesC, intracellular ice is likely to form, with subsequent damage to cellular structures. However, it cannot be assumed that subzero temperatures will freeze the cell. In this study, we attempted to confirm the specific freezing point of rat liver and to preserve it at a temperature just above that point.

METHODS

Rat livers were stored for 24, 48, 72, and 96 h either at 4 degreesC (Group N) or at -0.8 degreesC (just above the temperature ascertained to be the specific freezing point of rat liver; Group H). After cold storage, the livers were perfused for 60 min using an isolated perfused liver model for assessment of liver function.

RESULTS

ATP and TAN (total adenine nucleotides) in reperfused liver tissues were significantly higher in Group H than in Group N for all preservation periods. ADP was significantly higher in Group H than in Group N for 24-, 72-, and 96-h preservation periods. Energy charge was significantly higher in Group H than in Group N for 24-, 48-, and 96-h preservation periods.

CONCLUSIONS

Regarding the content of ATP, ADP, and TAN and the adenylate energy charge, our results indicate that preservation at -0.8 degreesC is advantageous. This novel preservation technique seems to prolong the period that organs can be stored.

Inhibition of internal entry site (IRES)-mediated translation by a small yeast RNA: a novel strategy to block hepatitis C virus protein synthesis

The observation that poliovirus mRNA is not translated in the yeast Saccharomyces cerevisiae has led to the discovery of a small RNA (60 nt, called IRNA, inhibitor RNA) which was later shown to specifically inhibit internal ribosome entry site (IRES)-mediated translation of naturally uncapped mRNAs. Translation of cellular capped mRNAs was not significantly inhibited by IRNA. IRNA also specifically inhibited hepatitis C virus (HCV) IRES-mediated translation in vitro and in vivo. A hepatoma cell line constitutively expressing IRNA was refractory to infection by a chimeric poliovirus (PV/HCV) in which PV IRES is replaced by HCV-IRES. In contrast, a PV/EMCV chimeric virus containing the EMCV IRES was not significantly inhibited in the IRNA-hepatoma cell line compared to the control hepatoma cells. UV-crosslinking studies showed that the IRNA binds a number of cellular proteins that appear to be important for IRES-mediated translation. Interaction of these proteins with the viral IRES elements is believed to be important in recruiting ribosomes to the 5( UTR of viral RNAs. The binding of the purified La autoantigen to the HCV IRES element was efficiently and specifically competed by IRNA. These results provide a basis for development of novel drugs effective against HCV infection.

Transforming growth factor alpha up-regulates desmin expression during embryonic mouse tongue myogenesis

Myogenesis is determined by a set of myogenic differentiation factors that are, in turn, regulated by a number of peptide growth factors. During embryonic mouse tongue formation, transforming growth factor alpha (TGF alpha), epidermal growth factor (EGF), and their cognate receptor (EGFR) are co-expressed spatially and temporally with desmin, a muscle-specific structural protein. This investigation tested the hypothesis that TGF alpha directly regulates the myogenic program in developing tongue myoblasts. Mandibular processes from the first branchial arch of embryonic day 10.5 (E10.5) mouse embryos were microdissected and explanted into an organ culture system using serumless chemically defined medium. Exogenous TGF alpha at 10 and 20 ng/ml specifically increased the amount of desmin expression and the number of desmin-positive cells without affecting the general growth and development of the mandibles. This inductive response was detected as early as 2 days after treatment and sustained up to 9 days in culture. EGFR antisense oligonucleotides (30 microM) as well as tyrphostin (80 microM) were able to negate TGF alpha-induced up-regulation of desmin expression. These data indicate that autocrine and/or paracrine action of TGF alpha promotes tongue myogenesis, and that this action is mediated through functional kinase activity of the EGFR. We speculate that the myogenic program in the developing mouse tongue is dependent upon growth factor mediated cell-cell communication of mesenchymal cells originating from the occipital somites and ectomesenchymal cells originating from the cranial neural crest.

A small yeast RNA blocks hepatitis C virus internal ribosome entry site (HCV IRES)-mediated translation and inhibits replication of a chimeric poliovirus under translational control of the HCV IRES element

Hepatitis C virus (HCV) infection frequently leads to chronic hepatitis and cirrhosis of the liver and has been linked to development of hepatocellular carcinoma. We previously identified a small yeast RNA (IRNA) capable of specifically inhibiting poliovirus (PV) internal ribosome entry site (IRES)-mediated translation. Here we report that IRNA specifically inhibits HCV IRES-mediated translation both in vivo and in vitro. A number of human hepatoma (Huh-7) cell lines expressing IRNA were prepared and characterized. Constitutive expression of IRNA was not detrimental to cell growth. HCV IRES-mediated cap-independent translation was markedly inhibited in cells constitutively expressing IRNA compared to control hepatoma cells. However, cap-dependent translation was not significantly affected in these cell lines. Additionally, Huh-7 cells constitutively expressing IRNA became refractory to infection by a PV-HCV chimera in which the PV IRES is replaced by the HCV IRES. In contrast, replication of a PV-encephalomyocarditis virus (EMCV) chimera containing the EMCV IRES element was not affected significantly in the IRNA-producing cell line. Finally, the binding of the La autoantigen to the HCV IRES element was specifically and efficiently competed by IRNA. These results provide a basis for development of novel drugs effective against HCV infection.

Induced expression of myoD, myogenin and desmin during myoblast differentiation in embryonic mouse tongue development

Significant progress has been made in defining mechanisms governing myogenesis at the transcriptional levels, but the extracellular signal-transduction pathways involved in myogenesis are not as yet defined. The developing mouse tongue provides a model for the regulation of myogenesis during precise time periods in embryogenesis. The molecular cues that regulate the close-range autocrine and/or paracrine signalling processes required for the fast-twitch complex tongue musculature are not known. This study was designed to test the hypothesis that transforming growth factor-alpha (TGF alpha) controls myogenesis in embryonic mouse tongue through the induction of myogenic regulatory factors such as myoD, myf5, myogenin and MRF4/myf6/herculin. To test this hypothesis, the effects of exogenous TGF alpha on the transcription of myoD, myf5, myogenin, MRF4 and desmin were examined in tongue samples from embryonic day-10.5 mandibular explants cultured in serum-free, chemically defined medium and then processed for competitive, reverse transcription-polymerase chain reaction. TGF alpha induced myoD, myogenin and desmin expression. Treatment with 20 and 40 ng/ml TGF alpha decreased or downregulated myf5 mRNA. MRF4 was not detected in the explants. TGF alpha apparently induces the early developmental stages of myogenesis through sequential upregulation of myoD and myogenin, downregulation of myf5 and corresponding significant increases in muscle-specific gene expression such as desmin transcription.

Dose-response effects of adrenergic drugs on axial movements of the rat mandibular incisor and on arterial blood pressure

Axial tooth movements and arterial blood pressure were measured following the intravenous injection of 0, 0.01, 0.1, 1, or 10 micrograms/kg of adrenaline, noradrenaline or isoprenaline. Adrenaline caused a dose-dependent, rapid, extrusive tooth movement with a nearly simultaneous increase in blood pressure, followed by a marked intrusive tooth movement and a decrease in blood pressure. Noradrenaline caused a dose-dependent, rapid, extrusive tooth movement and an increase in blood pressure, but a subsequent intrusive tooth movement and decrease in blood pressure were not so marked. Isoprenaline caused a marked intrusive tooth movement and a decrease in blood pressure, without an extrusive tooth movement and increase in blood pressure. The time required to reach the maximum intrusive tooth movement was delayed after that to reach the maximum decrease in blood pressure. The recovery time of the intrusive tooth movement was much more delayed than that of blood pressure. These results suggest that the extrusive movement of the rat incisor was primarily related to the rise of arterial blood pressure due to stimulation of vascular alpha-receptors. It is also suggested that stimulation of beta-receptors would probably cause vasodilatation of arteries that would make the pressure in the small vessels in the microcirculation of the socket fall, so reducing the volume of blood and interstitial fluid in the socket followed by a marked and continuing intrusive tooth movement.

TGF-alpha, EGF, and their cognate EGF receptor are co-expressed with desmin during embryonic, fetal, and neonatal myogenesis in mouse tongue development

The developing mouse tongue provides a model for discrete patterns of morphogenesis during short periods of embryonic development. Occipital somite-derived myogenic cells interact with cranial neural crest-derived ecto-mesenchymal cells to form the musculature of the tongue. The biochemical signals that control close range autocrine and/or paracrine signaling processes required to establish the fast-twitch complex tongue musculature are not known. The present study was designed to test the hypothesis that desmin, epidermal growth factor (EGF), and transforming growth factor-alpha (TGF alpha) and their cognate receptor, epidermal growth factor receptor (EGFr), are co-expressed during tongue myogenesis and define specific developmental stages of tongue muscle cell differentiation. To test this hypothesis, we performed studies to analyze the timing, position, and concentration of desmin, TGF alpha, EGF, and EGFr from embryonic day 9 (E9) through birth in Swiss Webster mouse tongue development. Desmin, TGF alpha, EGF, and EGFr co-localized to cells of myogenic lineage in the four occipital somites and subsequently in myoblasts and myotubes from E9 through E17. By newborn stage, desmin is localized to discrete regions in myofibers corresponding to Z-line delimiting sarcomeres, and A-band within sarcomeres; immunostaining for desmin, TGF alpha, and EGF persisted in differentiated myotubes and striated skeletal muscle. Desmin increased from 0.01% at E11 to 0.51% of the total protein by E17 and at birth. Concomitantly, the patterns and increases in TGF alpha, EGF, and EGFr showed significant increases during the same developmental period. The temporal and positional co-localization of TGF alpha, EGF, and EGFr support the hypothesis that autocrine and paracrine regulation of desmin by actions of growth factor ligand and receptor defines critical stages of tongue myogenesis.

X-ray crystal structure determination and molecular dynamics simulation of prophospholipase A2 inhibited by amide-type substrate analogues

X-ray crystal structures of bovine pancreas prophospholipase A2 (proPLA2) inhibited by two amide-type inhibitors, [(R)-2-dodecanoyl-amino-1-hexanolphosphocholine (DAHPc) and (R)-2-dodecanoylamino-1-hexanolphosphoglycol (DAHPg)], were determined to R = 0.208 and 0.215 using reflections with up to 2.1 A resolution, respectively. Both complex crystals lacked defined electron densities for the prosequence of the N-terminal and for a loop region consisting of residues 65-70, retaining the disordered feature observed in free proPLA2 despite stabilization due to complex formation. The polar and nonpolar moieties of the amide-type inhibitors were located in the calcium-binding pocket and in the N-terminal alpha-helical hydrophobic region of the enzyme, respectively. As for the amide group of the inhibitor, which is lacking in the true substrate, a strong hydrogen bond was formed between the NH of the inhibitor and the unprotonated N(delta1) atom of His-48, resulting in the tight binding of the inhibitor to proPLA2, as well as to PLA2. The 20-30 times more potent inhibitory activity of DAHPg than DAHPc toward PLA2 could be explained by hydrogen bond formation between the glycol OH of DAHPg and the carbonyl O of Asp-49. The seven residues of the N-terminal prosequence of proPLA2, though disordered, block the access of a water molecule to Ala-1 of PLA2 or change the hydrogen-bonding property of Ala-1 alpha-amino group, resulting in breakage of the water-mediated hydrogen-bond network which is commonly formed in PLA2. The results of molecular dynamics (MD) calculation in an aqueous solution at 300 K indicate that this, rather than the close contact between the prosequence and the residues 65-70 loop region, is the main reason why the latter region becomes flexible in proPLA2, compared with in PLA2.

In vitro measurement of orthodontic tooth movement in rats given beta-aminopropionitrile or hydrocortisone using a time-lapse videotape recorder

In vitro tooth movement of rat molars in response to an orthodontic force was recorded using a time-lapse videotape recorder and analysed by a computer system. Rats received daily s.c. injections of beta-aminopropionitrile (BAPN, 300 mg/kg/day) or hydrocortisone (10 mg/kg/day) for a period of 7 days. After drug administration, the animals were killed and the mandibles dissected. The jaw was then held under a stereomicroscope with a haemostatic clamp and an elastic band was inserted between the first and second molars. The movements of reference points on the occlusal surfaces of the first and second molars were recorded for 20 hours using a time-lapse videotape recorder. Mesiolingual movement of the first molar and distobuccal movement of the second molar were observed. During the experimental period, the greatest amount of total tooth movement in the first and second molars was seen in the group pretreated with BAPN, less movement was observed in the control group, and the group pretreated with hydrocortisone exhibited the least amount of movement. The highest rates of tooth movement were observed during the initial hour in each of the groups, and decreased thereafter. The initial rates of movement were also greatest in the BAPN group, less in the control group, and least in the hydrocortisone group. These results indicate that treatment with BAPN accelerated experimental tooth movements in vitro and hydrocortisone treatment inhibited the movements, suggesting that, although a part of the tooth movement measured in this experiment was due to deformation of the alveolar bone, the mechanical properties of the periodontal ligament play an important role in the regulation of orthodontic tooth movement.

Routine low and high resolution typing of the HLA-DRB gene using the PCR-MPH (microtitre plate hybridization) method

We describe HLA-DRB1 typing using polymerase chain reaction-based microtitre plate hybridization (PCR-MPH), which can process large numbers of samples. MPH typing is similar to an enzyme-linked immunosorbent assay (ELISA), in which a tandemly ligated sequence-specific oligonucleotide is immobilized on microtitre wells. The typing procedure consisted of two steps. In the first, PCR-MPH with 16 probes was performed to determine the specificities of the serological levels (DR1, DR2, DR3, DR4, DR11, DR12, DR13, DR14, DR7, DR8, DR9 and DR10) after generic amplification ("low resolution typing'). In the second step, DR1, DR2, DR4, DR12/8 and DR3/11/13/14 were group-specifically amplified based on the results of the first PCR-MPH, and microtitre plate hybridization proceeded in a similar manner to the first step ("high resolution typing'). Low resolution typing was completed within 2 h after generic amplification, and the results of high resolution typing were obtained in another 3.5 h after amplification. The allelic types classified using PCR-MPH were completely concordant with those obtained by PCR-single-strand conformation polymorphism or PCR-restriction fragment length polymorphism.

Large-scale DNA typing for human platelet alloantigens by PCR-PHFA (preferential homoduplex formation assay)

Alloimmunization against human platelet alloantigens (HPA) is known to be involved in disorders such as neonatal alloimmune thrombocytopenic purpura, posttransfusion purpura, and refractoriness to platelet transfusion therapy. HPA typing is essential in diagnosis and management of patients. Therefore a reliable and speedy method is necessary for HPA typing. We have successfully applied a new DNA typing method, PCR-preferential homoduplex formation assay (PHFA) method, to typing for the HPA-1, -2, -3, -4, -5 and -6 systems. This method is based on DNA strand competition during hybridization under a precisely controlled temperature gradient between a double-labelled amplicon (standard DNA), prepared from biotin- and DNP-labelled primers, and an unlabelled amplicon (sample DNA). The results obtained by PCR-PHFA typing were in good agreement with the allotypes determined by serological typing and by other DNA typing methods. The PCR-PHFA method can be easily automated, is suitable for typing both small and large numbers of samples, and thus is applicable to routine HPA typing.

Directly repeated insertion of 9-nucleotide sequence detected in penicillin-binding protein 2B gene of penicillin-resistant Streptococcus pneumoniae

We investigated the molecular mechanism of 50 penicillin-resistant Streptococcus pneumoniae strains (penicillin: MIC, > or = 0.125 microgram/ml) having neither class A nor class B mutations in the penicillin-binding protein 2B gene (pbp2b). An analysis of the nucleotide sequences of the pbp2b genes from seven strains revealed an unique direct repeat of 9 nucleotides (TGGTATACT) between active-site serine (residue 385) and Ser-X-Asn (residues 442 to 444) motifs. The same insertion was detected in 13 strains.

Combinational detection of autolysin and penicillin-binding protein 2B genes of Streptococcus pneumoniae by PCR

PCR was used to identify penicillin resistance in 1,062 clinical isolates of Streptococcus pneumoniae. Three sets of primers were designed to amplify (i) a 240-bp fragment of the penicillin-binding protein (PBP) 2B gene (pbp2b) of penicillin-susceptible S. pneumoniae (PSSP), (ii) a 215-bp fragment of the class A mutations of the pbp2b gene present in penicillin-resistant S. pneumoniae, and (iii) a 286-bp fragment of the class B mutation. In addition, a set of primers that amplify 273 bp of the autolysin (lytA) gene was applied in combination with the above to identify S. pneumoniae. Of 621 isolates for which MICs of penicillin were < or = 0.06 mu g/ml, 614 (98.9%) were ascertained as having DNA fragments amplified by the PSSP primers. Of 441 isolates for which MICs of penicillin were > or = 0.125 mu g/ml, a class A mutation was detected in only 8 (1.8%), a class B mutation was detected in 310 (70.3%), and neither class A nor class B mutations were found in the remaining 123 (27.9%). However, when analysis was limited to isolates for which MICs of penicillin were > or = 1.0 mu g/ml, 247 isolates (89.8%) of 275 were found to possess a class B mutation. When PBPs were analyzed in 12 isolates with unclear mutations of the pbp2b gene by using [3H]benzylpenicillin, low affinity to PBP 2B was observed in them all. These findings suggest that a pbp2b mutation other than class A or class B is present in these isolates. These results also indicate that it may be possible to identify PSSP and penicillin-resistant S. pneumoniae by applying PCR using a combination of primers to detect the susceptible pbp2b gene, resistant pbp2b gene mutations, and the lytA gene.

Polysaccharides in fungi. XXXVI. Hypoglycemic activity of a polysaccharide (CS-F30) from the cultural mycelium of Cordyceps sinensis and its effect on glucose metabolism in mouse liver

A polysaccharide (CS-F30) obtained from the cultural mycelium of Cordyceps sinensis showed potent hypoglycemic activity in genetic diabetic mice after intraperitoneal administration, and the plasma glucose level was quickly reduced in normal and streptozotocin-induced diabetic mice after intravenous administration. Administration of CS-F-30 to normal mice significantly increased the activities of hepatic glucokinase, hexokinase and glucose-6-phosphate dehydrogenase, although the glycogen content in the liver was reduced. Furthermore, CS-F30 lowered the plasma triglyceride level and cholesterol level in mice.

[Detection of mutations in the CFTR gene using the PCR-dependent preferential homoduplex formation assay (PCR-PHFA) system]

A simple and efficient method for detecting DNA alterations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene has been developed using polymerase chain reaction dependent preferential homoduplex formation assay (PCR-PHFA). The technique is based on strand competition between a double labeled amplicon and an unlabeled amplicon during hybridization in a precisely controlled temperature gradient. By using this method the presence of single base substitutions in a PCR amplicon can be detected. In this report, experimental evaluation of the PCR-PHFA system in DNA analysis of exons of the CFTR gene with the highest frequency of most common disease-causing mutations is presented. The method was capable of detecting all mutations tested within the amplified regions of genomic DNA. PCR-PHFA can be used for mutation screening of CFTR and potentially other genes with a large number of reported mutations.

Species-specific PCR detection of malaria parasites by microtiter plate hybridization: clinical study with malaria patients

A simple and convenient PCR method that amplifies the 18S rRNA genes has been developed for the purpose of detecting and differentiating four species causing malaria in humans. The advantage of the assay is that the biotinylated PCR product is visualized following hybridization with specific probes which are immobilized on plate wells (microtiter plate hybridization). This method has been previously evaluated in a field study and was found to be sensitive and specific for the detection of Plasmodium falciparum and Plasmodium vivax. In the current study, the microtiter plate hybridization PCR method was evaluated by using blood specimens from malaria patients. All of 36 cases of falciparum malaria, 26 of 27 cases of vivax malaria, all of 11 cases of ovale malaria, and 2 cases of malariae malaria were diagnosed species specifically by the PCR method. There were four smear-negative, PCR-positive cases that seemed to correspond to the convalescent stage of malaria. In contrast, 30 cases for which the diagnosis of malaria has been excluded on the basis of microscopy and clinical courses showed negative PCR results. By comparing parasite densities and PCR results following antimalarial treatment of some patients, it was revealed that the PCR results largely paralleled the parasite densities and that PCR could detect as few as 10 parasites per microliter of blood. We conclude that this PCR method is highly sensitive and specific for the detection of all four parasite species and can serve as a useful supplement to microscopy for the clinical management of malaria.

A simple method of HLA-DRB typing using enzymatically amplified DNA and immobilized probes on microtiter plate

We have developed a simple and economical method for HLA-DNA typing, called microtiter plate hybridization (PCR-MPH), which could replace standard PCR-SSO. This method is similar to that of an ELISA. Briefly, the PCR products labeled at the 5' termini with biotin were hybridized with probes immobilized on a microtiter well, and the bound PCR products were detected by streptavidin-conjugated enzymes followed by color development. A system for HLA-DRB1 "generic" typing (e.g., DR1, DR2), using microtiter wells coated with 12 different SSOs has been established. The HLA-DRB types classified using this method agreed well with those obtained by conventional serologic typing. The advantages of this microtiter plate-hybridization method for routine HLA-DNA typing are a short assay time, easy processing of large numbers of samples, and the potential for automation.

A new communication system between hepatocytes and sinusoidal endothelial cells in liver through vascular endothelial growth factor and Flt tyrosine kinase receptor family (Flt-1 and KDR/Flk-1)

Hepatocyte Growth Factor (HGF)/Scatter Factor secreted from sinusoidal endothelial cells and Kupffer cells in liver activates the c-Met tyrosine kinase receptor expressed on hepatocytes. Here we report yet another possible communication system through a different ligand and tyrosine kinase receptor in an opposite direction. We isolated and determined the primary structure of the entire coding region of rat flt-1 (fms-like tyrosine kinase), a receptor for Vascular Endothelial Growth Factor (VEGF). Using rat flt-1 cDNA as a probe we found that the flt-1 mRNA was expressed at very high levels in sinusoidal endothelial cells in normal rat liver, but was hardly detectable in hepatocytes. The transcripts of another VEGF receptor KDR/Flk-1 structurally related to Flt-1 was also expressed specifically in sinusoidal endothelial cells. On the other hand, VEGF mRNA was expressed weakly in hepatocytes, but not in the nonparenchymal cell fraction. Furthermore, in an in vitro culture system, VEGF demonstrated a remarkably specific growth-stimulatory activity as well as maintenance activity on the sinusoidal endothelial cells. These results suggest that hepatocytes regulate the proliferation and survival of the sinusoidal endothelial cells in liver in a paracrine manner. Therefore two reciprocal communication systems, VEGF-Flt receptor family and HGF-Met receptor, may exist in hepatic tissue.