Analysis of a dextran-binding domain of the dextranase of Streptococcus mutans

AIMS

To examine the dextran-binding domain of the dextranase (Dex) of Streptococcus mutans.

METHODS AND RESULTS

Deletion mutants of the Dex gene of Strep. mutans were prepared by polymerase chain reaction and expressed in Escherichia coli cells. Binding of the truncated Dexs to dextran was measured with a Sephadex G-150 gel. Although the Dexs which lacked the N-terminal variable region lost enzyme activity, they still retained dextran-binding ability. In addition, further deletion into the conserved region from the N-terminal did not influence the dextran-binding ability. However, the Dex which carried a deletion in the C-terminus still possessed both enzyme activity and dextran-binding ability. Further deletion into the conserved region from the C-terminal resulted in complete disappearance of both enzyme and dextran-binding activities.

CONCLUSIONS

Deletion analysis of the Dex gene of Strep. mutans showed that the C-terminal side (about 120 amino acid residues) of the conserved region of the Dex was essential for dextran-binding ability.

SIGNIFICANCE AND IMPACT OF THE STUDY

The dextran-binding domain was present in a different area from the catalytic site in the conserved region of the Dex molecule. The amino acid sequence of the dextran-binding domain of the Dex differed from those of glucan-binding regions of other glucan-binding proteins reported.

Leukotriene receptor antagonist, montelukast, can reduce the need for inhaled steroid while maintaining the clinical stability of asthmatic patients

BACKGROUND

Oral leukotriene receptor antagonists have been shown to have efficacy in chronic asthma.

OBJECTIVE

To determine whether the addition of montelukast could lead to a reduction in inhaled corticosteroid dose without a significant decrease in peak expiratory flow rate (PEFR).

METHODS

After a 4-week run-in period, 191 moderate-to-severe asthmatic patients whose asthma had been well controlled with daily inhaled corticosteroid therapy (beclometasone dipropionate 800 to 1600 micro g/day), were randomly assigned to one of two treatments - placebo (n = 98) or montelukast 10 mg once daily (n = 93) - for a 24-week, multicentre, double-blind, treatment period. At the beginning of the active treatment period, the daily dose of inhaled corticosteroid was halved in all of the patients. In addition, the inhaled corticosteroid dose was subsequently titrated every 8 weeks, based on PEFR, asthma symptoms and beta-agonist use.

RESULTS

After 8 weeks of a 50% reduction in inhaled corticosteroid use, morning PEFR increased by 5.3 +/- 32.3 L/min from baseline in patients receiving montelukast and significantly decreased by 6.9 +/- 29.0 L/min in those receiving placebo (P = 0.035). In addition, evening PEFR significantly decreased by 9.8 +/- 28.5 L/min (P = 0.003) in the placebo group, but was maintained in the montelukast group. In spite of a subsequent 50% reduction in the inhaled corticosteroid dose every 8 weeks, morning and evening PEFRs were maintained over the 24-week treatment period in the montelukast group; PEFR significantly decreased in the placebo group. There was a significant difference between the two groups with regard to morning PEFR, therapy score and asthmatic score at weeks 8, 16 and 24, as well as evening PEFR at week 8. However, the symptom scores were not significantly different between the two groups or within each group.

CONCLUSION

These data suggest that montelukast reduces the need for inhaled corticosteroids while maintaining asthma control over a 24-week period. Therefore, montelukast may be useful for long-term treatment in patients with asthma who require high doses of inhaled corticosteroids.

Prognostic significance of changes in prostate-specific antigen in patients with metastasis prostate cancer after endocrine treatment

Patients with metastatic prostate cancer respond to androgen withdrawal therapy, but progression to androgen independence is frequently observed. To clarify the predictor of response to endocrine therapy, the role of PSA changes and the prognosis of the patients were evaluated in 115 Japanese cases of prostate cancer with distant metastases treated with androgen withdrawal therapy. When patients were divided according to the pretreatment PSA value (high, > or = 500, median; 500 > PSA > or = 100, low; 100 >), patients whose initial PSA levels were high had a worse cause-specific survival. PSA value at 3 or 6 months following endocrine treatment, PSA nadir, and percent decrease of PSA were associated with prolonged survival. Clinical relapse was observed in 68 patients. Patients with distant recurrence had shorter time to PSA elevation than those with local recurrence. In metastatic prostate cancer patients treated with androgen withdrawal, serial measurement of PSA could distinguish nonfavorable responders early in the course of treatment and assist in monitoring for disease progression.

Factors affecting toxicity, response and progression-free survival in relapsed patients with indolent B-cell lymphoma and mantle cell lymphoma treated with rituximab: a Japanese phase II study

BACKGROUND

The aim of the study was to determine factors affecting the toxicity and efficacy of rituximab monotherapy in relapsed patients with indolent B-cell lymphoma and mantle cell lymphoma (MCL).

PATIENTS AND METHODS

A total of 90 patients were enrolled and treated with rituximab infusions at 375 mg/m2 once weekly for 4 weeks. Central pathology review revealed that histologically, 81 patients had indolent B-cell lymphoma or MCL: 59 with follicular lymphoma, 17 with MCL, four with marginal zone lymphoma and one with lymphoplasmacytoid lymphoma. Of these, four were ineligible due to violation of other eligibility criteria. Pre-treatment variables affecting toxicities were analyzed for all 90 patients, and those affecting response and progression-free survival (PFS) were analyzed for 77 eligible patients with confirmed indolent B-cell lymphoma or MCL. The relationship between serum rituximab levels and efficacy was also analyzed for 66 eligible patients.

RESULTS

Hematological toxicities (grade > or =3) occurred more frequently in females (P <0.05), and thrombocytopenia and leukopenia were more frequent in patients with high lactate dehydrogenase (LDH) levels (P <0.05). Non-hematological toxicities (grade > or =2) were more frequent in patients with extranodal disease or bone marrow involvement. The overall response rate (ORR) in patients receiving one prior chemotherapy regimen was higher than those receiving two or more regimens (P <0.05). The median PFS was shorter in MCL patients, in those with extranodal disease, or in those receiving two or more prior chemotherapy regimens (P <0.01). The PFS intervals of patients with higher serum rituximab levels (> or =70 microg/ml) immediately before the third infusion were longer than in other patients (P <0.01).

CONCLUSIONS

Several prognostic factors and serum rituximab levels are useful for predicting the toxicity and efficacy of rituximab monotherapy.

An essential amino acid residue for catalytic activity of the dextranase of Streptococcus mutans

Dextranase (Dex) is an enzyme that hydrolyzes glucan, a polymer of glucose synthesized from sucrose by glucosyltransferases (GTFs). By comparing amino acid sequences of Dexs and GTFs, we found that the Dex enzymes of Streptococcus mutans, Streptococcus sobrinus, Streptococcus downei and Streptococcus salivarius had similar amino acid sequences to those of the catalytic sites of GTFs of mutans streptococci. We therefore examined the amino acid essential in Dex catalysis by molecular genetic approaches in this study. Site-directed mutagenesis was used to convert the Asp-385 of the Dex molecule of S. mutans Ingbritt to Glu, Asn, Thr or Val. Replacement of Asp-385 with any of the amino acids resulted in complete disappearance of Dex activity. However, replacement of other Asp residues did not affect the enzyme activity. The inactive enzymes still retained dextran-binding ability. These results suggest that Asp-385 of the Dex of S. mutans Ingbritt was essential for enzyme activity and the catalytic and substrate-binding sites were located at different sites within the Dex molecule.

Absolute configuration at C14 and C85 in prymnesin-2, a potent hemolytic and ichthyotoxic glycoside isolated from the red tide alga Prymnesium parvum

Prymnesin-2 is a potent red tide toxin characterized by a highly oxidized C(90) carbon chain and multiple functional groups. Succeeding the assignment of the relative stereochemistry in the polycyclic-ether segment, the absolute configurations of two chiral centers in linear chain parts were elucidated. The configuration at C14 bearing an amino group was determined to be S by using a chiral anisotropic reagent and that at chlorinated C85 to be S by fluorimetric chiral HPLC comparison between a degradation product and synthetic references.

Nucleotide sequence and molecular characterization of a dextranase gene from Streptococcus downei

DNA fragments encoding the Streptococcus downei dextranase were amplified by PCR and inverse PCR based on a comparison of the dextranase gene (dex) sequences from S. sobrinus, S. mutans, and S. salivarius, and the complete nucleotide sequence of the S. downei dex was determined. An open reading frame (ORF) of dex was 3,891 bp long. It encoded a dextranase protein (Dex) consisting of 1,297 amino acids with a molecular mass of 139,743 Da and an isoelectric point of 4.49. The deduced amino acid sequence of S. downei Dex had homology to those of S. sobrinus, S. mutans and S. salivanus Dex in the conserved region (made of about 540 amino acid residues). DNA hybridization analysis showed that a dex DNA probe of S. downei hybridized to the chromosomal DNA of S. sobrinus as well as that of S. downei, but did not to other species of mutans streptococci. The C terminus of the S. downei Dex had a membrane-anchor region which has been reported as a common structure of C termini of both the S. mutans and S. sobrinus Dex. The recombinant plasmid which harbored the dex ORF of S. downei produced a recombinant Dex enzyme in Escherichia coli cells. The analysis of the recombinant enzyme on SDS-PAGE containing blue dextran showed multiple active forms as well as dextranases of S. mutans, S. sobrinus and S. salivarius.

Cloning and characterization of the Xenopus laevis p8 gene

The p8 gene encodes a transcription factor with a basic helix-loop-helix motif and has been cloned in rat, mouse and human. It is upregulated in acute pancreatitis. In the present study, the Xenopus laevis homolog of p8 (Xp8) was isolated by PCR. The full-length Xp8 cDNA consists of 677 bp and encodes 82 amino acids. The basic helix-loop-helix region is well conserved between X. laevis and mammals. Overexpression of an Xp8-EGFP fusion protein indicated that Xp8 was localized to nucleus, as in mammals. Analysis by RT-PCR showed that expression of Xp8 was increased after gastrulation and maintained into later developmental stages. Expression was detected in the prospective neural region at the neurula stage by whole-mount in situ hybridization. At the larval stage, Xp8 was expressed in central nervous regions, such as ventrolateral brain, trigeminal nerve, vestibulocochlear nerve and dorsal neural tube. Expression was also detected in the basal cement gland, olfactory placode, ear vesicle, notochord and anus. This specific pattern of expression suggests that Xp8 may play a role in the development of the central nervous system in X. laevis.

Regional vulnerability after traumatic brain injury: gender differences in mice that overexpress human copper, zinc superoxide dismutase

Neuronal loss was quantified in both cortical and subcortical brain regions after traumatic brain injury in male and female nontransgenic (nTg) and transgenic (Tg) mice that overexpress human copper, zinc superoxide dismutase. Mice were euthanized at 7 days after a controlled cortical impact injury. Sections of brain were processed for immunolocalization of NeuN, a neuronal nuclear antigen, and the complement type 3 receptor, a marker of microglia/macrophages, and stained for iron. Cortical lesion volume and neuronal loss in the medial and/or lateral ventroposterior thalamic nuclei were significantly less in the nTg female compared to the nTg male (P = 0.0373 and P = 0.0023, respectively). In contrast, in CA3 of the hippocampus and laterodorsal thalamic nucleus (LD), there were no gender differences in neuronal loss between these nTg groups. Cortical lesion volume was significantly reduced in Tg males compared to nTg males (P = 0.0137) and was unchanged in the Tg females compared to the nTg females. Neuronal loss was attenuated in the CA3 and LD in the Tg females compared to the nTg females (P = 0.0252 and P = 0.0244, respectively). A similar protection was not observed in the Tg males. Microglial activation paralleled the pattern of neuronal loss and was most consistently aligned with iron deposition in the cortex and hippocampus. No overt differences were found in the pattern of microglial activation or iron staining between nTg and Tg mice nor between genders. Our findings demonstrate that neuroprotection, afforded by overexpression of copper, zinc superoxide dismutase, exhibits both regional and gender specificity.

Differences in anti-LKM-1 autoantibody immunoreactivity to CYP2D6 antigenic sites between hepatitis C virus-negative and -positive patients

Anti-liver kidney microsome type 1 autoantibodies (anti-LKM-1) are known to be present in sera of autoimmune hepatitis type II and a subset of chronic hepatitis C patients. The autoantigen to anti-LKM-1 has been identified to be cytochrome P450 IID6 (CYP2D6) and the most frequently cited CYP2D6 antigenic sites of anti-LKM-1 in sera from autoimmune hepatitis type II patients spans the region aa 256-269. Other antigenic sites on CYP2D6 exist and have been identified in the two patient groups. However, most of these sites are concentrated on the carboxyl-terminal side of the protein, and the amino-terminal region has not been thoroughly investigated. Here, we have studied the antigenicity of the CYP2D6 amino region and compared reactivities between hepatitis C virus (HCV)-negative and -positive Japanese patient groups. A total of 34 anti-LKM-1-positive sera (eight with autoimmune hepatitis type II and 26 with chronic hepatitis C) were included. The immunoreactivity of patients' sera was examined against four conformational and one linear CYP2D6 peptide fragments. A defined antigenic site spanning aa 181-245 was found to react with 88% (7/8) of autoimmune hepatitis type II patients, as opposed to only 38% (10/26) of chronic hepatitis C patients. This was a significant difference (P< 0.043). Among these positively reacting samples, five of the seven autoimmune hepatitis type II sera and four of the ten chronic hepatitis C sera also reacted with a synthetic peptide spanning aa 256-269. Anti-LKM-1 thus may be able to recognize simultaneously at least two antigenic sites on the CYP2D6 protein, and reactivities against individual epitopes may differ according to HCV infectivity status.

[Epiduroscopy in patients with chronic low back pain without remarkable findings on magnetic resonance imaging]

Two patients with chronic low back pain and sciatica failed to respond to conservative treatments. In these patients, magnetic resonance imaging (MRI) showed no remarkable findings corresponding to their symptoms. We treated these patients using epiduroscopy. Epiduroscopic visualization of the spinal canal permits efficient adhesiolysis and irrigation. One patient got better after two epiduroscopic procedures, and the other did not. Epiduroscopy may be an effective, minimally invasive treatment as well as examination for patients with chronic low back pain without remarkable findings on MRI.

Neuronal injury and loss after traumatic brain injury: time course and regional variability

We have examined regional neuronal injury after traumatic brain injury using Fluoro-Jade, an acidic dye that exhibits a marked affinity for both the degenerating neuronal cell body and its processes and have determined the extent to which early injury corresponds to regional patterns of neuronal loss. Rats (n=45) were subjected to lateral fluid percussion brain injury and euthanized at 3 h to 28 days post injury. Complementary Fluoro-Jade, silver impregnation methods and TUNEL were used to assess neuronal injury. Neuronal loss was evaluated in sections immunostained for NeuN, a neuronal specific nuclear protein. Overt neuronal cell loss was evident by 7 days post injury in the cortex, hippocampus and thalamus. Injured neurons were apparent in the ipsilateral cortex bordering the impact site, hippocampus (CA1 and dentate), thalamus, and vermis of the cerebellum as early as 3 h post injury. Degenerating neurons were maximal by 1 and 3 days in the cortex and hippocampus, by 3 and 7 days in the cerebellum, and by 7 days in the thalamus. The regional distribution of Fluoro-Jade-labeled neurons corresponded to a similar pattern of silver and TUNEL staining. Together, these findings demonstrate a regionally specific temporal pattern of neuronal injury that results in overt neuronal cell loss within both cortical and subcortical regions.

Hypermethylation of the CD44 gene is associated with progression and metastasis of human prostate cancer

BACKGROUND

CD44 is a metastasis suppressor gene for prostate cancer and the down-regulation of CD44 and its variants is associated with the progression of prostate cancer. Also, hypermethylation of the CpG islands of the CD44 gene is closely associated with transcriptional inactivation, resulting in the decreased expression of CD44. To clarify the exact role of methylation status of CpG islands of CD44 gene in the progression and metastasis of prostate cancer, we investigated the methylation status of this gene in primary and metastatic human prostate tumors obtained from surgery or autopsy.

METHODS

We examined 97 samples from 40 Japanese patients with adenocarcinoma of the prostate. Tumor tissues were obtained from radical prostatectomy specimens from eight patients with stage B, 12 patients with stage C and three patients with stage D1 and at autopsy from 17 hormone-refractory metastatic cases, who had initially responded to the therapy and thereafter relapsed. Distant metastatic tissues were also obtained at autopsy (i.e., liver, lung, kidney, mammary gland, and pelvic lymph nodes) from 10 of 17 hormone-refractory cases. We analyzed the hypermethylation status of CD44 promotor region by PCR using genomic DNAs digested with the m(5)C-sensitive restriction enzyme HpaII.

RESULTS

The correlation between the methylation status of CD44 gene and the stage progression of prostate cancer was statistically significant (P = 0.0438). In two of 10 hormone-refractory cases, a comparison of the methylation status of the CD44 gene in metastases to that in primary tumors revealed interfocal heterogeneity of CD44 methylation status.

CONCLUSIONS

These results indicate an important role of CD44 methylation in the progression and metastasis of prostate cancer, although the amount of methylational heterogeneity is substantial among metastatic sites within the same patient.

Pretreatment serum level of testosterone as a prognostic factor in Japanese men with hormonally treated stage D2 prostate cancer

Pretreatment serum level of testosterone (T) is a potential prognostic factor for prostate cancer. However, T levels in Japanese prostate cancer patients are unknown to date. To evaluate the clinical significance of pretreatment serum T level in such patients, serum T level was analyzed in relation to several clinical factors in a total of 130 patients with various stages of prostate cancer, 74 of whom had metastatic disease (stage D2) and received endocrine therapy as first-line treatment. The mean pretreatment T level in patients with non-metastatic prostate cancer (stages B + C) was significantly lower than that in stage D2 patients (B + C: 4.05 +/- 2.01 ng/ml; D2: 4.85 +/- 2.18 ng/ml, p = 0.0344). On the other hand, the mean serum level of T was higher in stage D2 patients who showed good response to endocrine therapy (CR: 5.42 +/- 1.55 ng/ml; non-CR: 4.30 +/- 2.63 ng/ml, p = 0.0320). When the 74 stage D2 patients were divided into high and low T level groups according to the median value, those patients with a high T level had significantly better cause-specific and progression-free survival. Multivariate analysis demonstrated that extent of bone metastases (EOD) grade, pretreatment serum T level and tumor marker response to endocrine therapy were significant predictors for progression-free survival. In conclusion, a higher pretreatment T level appears to be predictive of the marker response to endocrine therapy, showing positive prognostic value and indicating good prognosis in patients at the metastatic stage. However, a higher T level was also associated with stage progression of this disease.

Phase I and pharmacological study of a new camptothecin derivative, exatecan mesylate (DX-8951f), infused over 30 minutes every three weeks

PURPOSE

A Phase I study of exatecan, a new water-soluble camptothecin derivative, was conducted to determine the maximum tolerated dose and a recommended dose, according to an internationally standardized core protocol. Pharmacological profiles of lactone and total (lactone + carboxylate) exatecan were also investigated.

PATIENTS AND METHODS

Fifteen patients with advanced solid malignancies were treated with 3, 5, and 6.65 mg/m(2) of exatecan infused over 30 min every 3 weeks. Concentrations of lactone, total drug, and a metabolite in plasma and urine were determined during the first course.

RESULTS

Dose-limiting neutropenia and liver dysfunction were observed in two of six patients at 6.65 mg/m(2), but no grade 3 or worse diarrhea was observed. Emesis was moderate, and no grade 3 or worse nausea and vomiting were observed at a recommended dose of 5 mg/m(2), with prophylactic use of granisetron. Pharmacokinetics were linear and had moderate variability; clearances of lactone and total drug were 6.8 +/- 2.8 and 2.1 +/- 1.1 (mean +/- SD) l/h/m(2), respectively. The ratio of lactone concentration to total drug concentration in plasma decreased from 0.81 +/- 0.06 at the end of infusion to 0.15 +/- 0.06 10 h after the infusion. The lactone:total ratio of drug exposure was 0.30 +/- 0.08, ranging from 0.16 to 0.43. Neutropenia was related to the drug exposure of both lactone and total drug.

CONCLUSIONS

The recommended dose of exatecan infused over 30 min every 3 weeks is 5 mg/m(2), with a favorable toxicity profile of mild and infrequent diarrhea. Interpatient variability of pharmacokinetics was similar to or smaller than that with other camptothecin derivatives.

Three families with autosomal dominant nephrogenic diabetes insipidus caused by aquaporin-2 mutations in the C-terminus

The vasopressin-regulated water channel aquaporin-2 (AQP2) is known to tetramerize in the apical membrane of the renal tubular cells and contributes to urine concentration. We identified three novel mutations, each in a single allele of exon 4 of the AQP2 gene, in three families showing autosomal dominant nephrogenic diabetes insipidus (NDI). These mutations were found in the C-terminus of AQP2: a deletion of G at nucleotide 721 (721 delG), a deletion of 10 nucleotides starting at nucleotide 763 (763-772del), and a deletion of 7 nucleotides starting at nucleotide 812 (812-818del). The wild-type AQP2 is predicted to be a 271-amino acid protein, whereas these mutant genes are predicted to encode proteins that are 330-333 amino acids in length, because of the frameshift mutations. Interestingly, these three mutant AQP2s shared the same C-terminal tail of 61 amino acids. In Xenopus oocytes injected with mutant AQP2 cRNAs, the osmotic water permeability (Pf) was much smaller than that of oocytes with the AQP2 wild-type (14%-17%). Immunoblot analysis of the lysates of the oocytes expressing the mutant AQP2s detected a band at 34 kD, whereas the immunoblot of the plasma-membrane fractions of the oocytes and immunocytochemistry failed to show a significant surface expression, suggesting a defect in trafficking of these mutant proteins. Furthermore, coinjection of wild-type cRNAs with mutant cRNAs markedly decreased the oocyte Pf in parallel with the surface expression of the wild-type AQP2. Immunoprecipitation with antibodies against wild-type and mutant AQP2 indicated the formation of mixed oligomers composed of wild-type and mutant AQP2 monomers. Our results suggest that the trafficking of mutant AQP2 is impaired because of elongation of the C-terminal tail, and the dominant-negative effect is attributed to oligomerization of the wild-type and mutant AQP2s. Segregation of the mutations in the C-terminus of AQP2 with dominant-type NDI underlies the importance of this domain in the intracellular trafficking of AQP2.

Re-treatment of relapsed indolent B-cell lymphoma with rituximab

The purpose of this study was to investigate the toxicity and the efficacy of re-treatment with rituximab, a chimeric mouse human anti-CD20 monoclonal antibody, in relapsed patients with indolent B-cell non-Hodgkin's lymphoma (NHL) who responded to rituximab in the previous phase I or phase II study. Thirteen patients with relapsed B-cell NHL, each of whom was confirmed to have Revised European-American Lymphoma Classification type II, 1-6 histology (indolent B-NHL), enrolled in this re-treatment study. All were re-treated with rituximab at 375 mg/m2 weekly for 4 consecutive weeks. Rituximab re-treatment was well tolerated with no grade 3/4 nonhematological toxicities, similar to that of the initial treatment. No patients developed detectable human anti-chimeric antibody. Partial responses were observed in 5 of 13 patients (38%; 95% confidence interval [CI], 14% to 68%); 6 patients showed stable disease and 2 showed progressive disease. Overall survival rate was 93% at 19 months of median follow-up after rituximab re-treatment. Median progression-free survival (PFS) after the re-treatment was 5.1 months (95% CI, 4.1 to 5.6 months), and the median PFS after the initial treatment was 8.2 months (95%CI, 5.9 to 11.3 months). Although rituximab re-treatment induced prolonged depletion of normal peripheral blood B cells in all patients, no significant decrease in serum immunoglobulin or complement level was observed. In conclusion, rituximab re-treatment was well tolerated, and it may produce a prolonged PFS in some patients with indolent B-cell NHL who showed initial response to rituximab.

Population pharmacokinetics of tacrolimus in adult recipients receiving living-donor liver transplantation

OBJECTIVE

To characterize the pharmacokinetics of tacrolimus in adult recipients receiving living-donor liver transplantation (LDLT).

METHODS

Thirty-five patients were given tacrolimus as 18- to 60-h intravenous infusions after surgery, followed by a 4-week course of oral dose therapy (at 0900 hours and 2100 hours). Blood samples were collected daily in the morning (0800 hours) beginning the day after surgery. Whole blood concentration data were evaluated by nonlinear mixed-effect modeling using the program NONMEM and were characterized using a one-compartment model.

RESULTS

The clearance (CL, l h(-1)) was related to the grafted hepatic weight, postoperative days (POD), and hepatic and renal dysfunction. Interindividual variabilities in CL, volume of distribution (V), and bioavailability (F) were 57.4%. 39.7%, and 63.0%, respectively, and the correlation between individual CL and F was 0.776. Residual intraindividual variability was 2.9 ng ml(-1). Based on the estimated final parameters, a typical recipient of LDLT with grafted hepatic weight of 600 g and normal hepatic and renal function would have a CL of 0.737 l h(-1) on POD 0 and 1.14 l h(-1) on POD 30, V of 1.52 l kg(-1) and F of 6.8%.

CONCLUSIONS

Nonlinear mixed-effect modeling was useful for analysis of pharmacokinetic characteristics of tacrolimus in LDLT patients. Immediately after surgery, patients receiving LDLT showed a smaller CL value than other transplant patients, and CL value increased with POD within 30 days after surgery. The estimated population pharmacokinetic parameters can be applied for a priori dosage calculations in adult patients with LDLT.

Fetal DNA diagnosis from maternal blood: PEP-TaqMan PCR analysis of a single nucleated erythrocyte (NRBC)

Development of a real-time quantitative TaqMan PCR assay permits the high-quality analysis of DNA or RNA. This study demonstrates the successful detection of single locus genes from single NRBCs, retrieved by micromanipulation of cells on a blood smear slide. Quantitative data in relation to the concentration of a single locus DNA amplified by PEP from a single NRBC are also provided. In summary, a PEP-TaqMan system can potentially be a powerful tool for noninvasive fetal DNA diagnosis through the use of maternal blood.