In situ product removal of ketoses by immobilized 3-amino phenyl boronic acid: effect of immobilization method on pH profile

The use of polymeric derivatives of phenylboronic acid (PBA) as an effective means for specific in situ product removal of ketoses from aldose-containing reaction mixtures, strongly depends on the retention of selective binding of ketoses exhibited by soluble PBA and 3-amino PBA, by their polymeric, water insoluble analogs. In this communication we demonstrate that immobilization chemistry has a strong effect on ketose preferred binding by polymeric PBA derivatives. Our results indicate that for the preparation of an effective and more specific adsorbent, 3-amino PBA should be coupled to the polymeric carrier via alkylamino chemistry and not via the commonly employed amido derivative. Immobilized alkylamino-PBA exhibited selective fructose and xylulose binding throughout glucose and xylose isomerization processes at the pH range of 7.0-8.0.

Percutaneous image-guided needle biopsy in children--summary of our experience with 57 children

BACKGROUND

Percutaneous image-guided needle biopsy in children has been slower to gain acceptance than in adults where it is regarded as the standard clinical practice in screening suspicious masses.

OBJECTIVES

To report our experience with percutaneous image-guided needle biopsy in the pediatric population and assess its clinical use, efficacy and limitations.

MATERIAL AND METHODS

Sixty-nine percutaneous image-guided needle biopsies were performed in 57 children. The age of the children ranged from 4 days to 14 years (mean 5.6 years). We used 16- to-20-gauge cutting-edge needles. Sixty-two biopsies were core-needle biopsies and 7 fine-needle aspiration biopsies.

RESULTS

There were 50 malignant lesions, 10 benign lesions and 2 infectious lesions. In 55 (88.7 %) lesions the needle biopsy was diagnostic. In 7 (11.3 %) the biopsy was non-diagnostic and the diagnosis was made by surgery. Core-needle biopsy was diagnostic in 47 of 50 (94 %) of the malignant solid tumors. In 3 out of 5 children with lymphoma, an accurate diagnosis was obtained with needle aspiration. Seven children underwent a repeated core-needle biopsy, (5 for Wilms' tumor and 2 for neuroblastoma) that was diagnostic in all cases. All the biopsies were performed without complications.

CONCLUSION

Percutaneous image-guided needle biopsy is a simple, minimally invasive, safe and accurate method for the evaluation of children with suspicious masses. These data suggest that image-guided needle biopsy is an excellent tool for diagnosing solid tumors in the pediatric population. Negative studies should be considered nondiagnostic and followed by excisional surgical biopsies when clinical suspicion of malignancy is high.

Nigrostriatal collaterals to thalamus degenerate in parkinsonian animal models

Movement, cognition, emotion, and positive reinforcement are influenced by mesostriatal, mesocortical, and mesolimbic dopamine systems. We describe a fourth major pathway originating from mesencephalic dopamine neurons: a mesothalamic system. The dopamine transporter, specific to dopamine containing axons, was histochemically visualized in thalamic motor and limbic-related nuclei and regions that modulate behavioral state as opposed to sensory nuclei in rats, nonhuman primates, and humans. Anatomical tracing established this innervation's origin via axon collaterals from the mesostriatal pathway. These findings implicate the thalamus as a novel site for disease specific alterations in dopamine neurotransmission, such as exist with nigral degeneration attending Parkinson's disease. This was confirmed in hemiparkinsonian animals where reduction of thalamic dopamine innervation occurred coincident with signs of active axonal degeneration. Individual mesencephalic dopamine neurons therefore have the potential to modulate normal and pathologic behavior not only through traditional nigrostriatal pathways but also by way of axon collaterals that innervate the thalamus.

T-cell--depleted allogeneic bone marrow transplantation followed by donor lymphocyte infusion in patients with multiple myeloma: induction of graft-versus-myeloma effect

Previous trials of allogeneic bone marrow transplantation (BMT) in patients with multiple myeloma (MM) have demonstrated high response rates but also high transplantation-related mortality (TRM) and high relapse rates. Exploitation of this strategy remains of interest because donor lymphocyte infusions (DLIs) can induce a potent graft-versus-myeloma (GVM) effect. CD6 T-cell--depleted allogeneic BMT was combined with prophylactic CD4(+) DLI administered 6 to 9 months after BMT in an effort to reduce TRM and to induce a GVM response after BMT. Twenty-four patients with matched sibling donors and chemotherapy-sensitive disease underwent BMT. CD6 T-cell depletion of donor bone marrow was the sole method of graft-versus-host disease (GVHD) prophylaxis. GVHD after BMT was minimal, 1 (4%) grade III and 4 (17%) grade II GVHD. Fourteen patients received DLI, 3 in complete response and 11 with persistent disease after BMT. Significant GVM responses were noted after DLI in 10 patients with persistent disease, resulting in 6 complete responses and 4 partial responses. After DLI, 50% of patients developed acute (> or = II) or extensive chronic GVHD. Two-year estimated overall survival and current progression-free survival (PFS) for all 24 patients is 55% and 42%, respectively. The 14 patients receiving DLI had an improved 2-year current PFS (65%) when compared with a historical cohort of MM patients who underwent CD6-depleted BMT survived 6 months with no GVHD and did not receive DLI (41%) (P =.13). Although this study suggests that prophylactic DLI induces significant GVM responses after allogeneic BMT, only 58% of patients were able to receive DLI despite T-cell--depleted BMT. Therefore, less toxic transplantation strategies are needed to allow a higher proportion of patients to receive DLI and the benefit from the GVM effect after transplantation. (Blood. 2001;98:934-939)

Levels of lipid peroxidation products in a chronic inflammatory disorder

We have examined the plasma levels of the lipid peroxidation products 4-hydroxy-nonenal and malondialdehyde in a carefully controlled study of age and sex-matched subjects with rheumatoid arthritis in whom potentially confounding influences such as disease modifying anti-rheumatic drugs (DMARDs), self-medication and vitamin supplements were eliminated. The plasma concentrations of the antioxidants uric acid and vitamin E were also measured. The results reveal a strong and consistent inverse correlation between the levels of lipid peroxidation products in the plasma and erythrocyte sedimentation rate (ESR). There is no indication that vitamin E or urate function as the major antioxidant agent in arthritis, as has been suggested in more seriously affected patients. It is concluded that there is no evidence that vitamin E is more important, and urate less important as an antioxidant in mild arthritis. The correlation between lipid peroxidation and ESR suggests a more complex relationship than has been assumed.

The environment and vegetation of the flux measurement site near Skukuza, Kruger National Park

The SAFARI-2000 intensive study site is located 13 km WSW of Skukuza. Detailed measurements of the exchanges of energy, water, carbon dioxide and other substances between the savanna and the atmosphere have been made there since April 2000. This paper provides basic information regarding the climate, soils and vegetation at the site. The site is located near the top of a gentle rise in an undulating granitic landscape. Most of the data were collected within a 300 m square centred on the flux tower situated at 25@01.184' S, 31@29.813' E and oriented true north. The tower stands exactly on the ecotone between a ridgetop broad-leafed Combretum savanna on sandy soil and a midslope fme-leafed Acacia savanna on clayey soil. The ecotone is marked by a 10 m wide band of sedges. The tree basal area within the sample square was 6.8 mVha (@ 1.0 standard error), the tree density 128 @ 16 plants/ha and the tree crown cover 24 @ 4 . Shrubs, defined as woody plants greater than 0.5 m but less than 2.5 m tall, contributed a further 7.6 crown cover. The basal area weighted mean height of the trees was 9 m, and the maximum height 13m. Nineteen woody plant species were recorded within the square, with 70 of the woody plant basal area dominated by Combretum apiculatum, Sclerocarya birrea and Acacia nigrescens. The rooted basal area of grasses was 7.1 @ 0.6 and in June 2000 the grass standing crop was 400 g DM m2.

Biologic factors and response to radiotherapy in carcinoma of the cervix

Ionizing radiation has been used to treat cancers for a century. However, radioresistance remains a major problem in the clinic. Recent advances in the understanding of the molecular events that occur following ionizing radiation leading to DNA damage and repair, apoptosis, and cell cycle arrests suggest new ways in which the radiation response might be manipulated. Seventy-eight cases of carcinoma of the cervix of the same stage (II A and B) were analyzed retrospectively. All patients were treated with radiotherapy (RT) with a dose varying from 35 Gy to 50 Gy with 200 cGy per fraction. Subsequent to the completion of radiotherapy, all patients underwent surgery 4-6 weeks later. On histological examination of the surgical specimens, 51% of the cases (40) showed a complete response to therapy with no viable tumor cells. 49% of cases (38) had residual tumors ranging from a small focus to lesions extending through more than half the thickness of the cervical wall. p53 (mutant), bcl-2, p21 and bax proteins were studied on the paraffin sections of the biopsies (pretreatment) of those patients who failed to respond to RT and compared to similar studies on biopsies of patients who had a complete response to RT. In addition, the minichromosome maintenance (MCM) 2 proliferative marker was also done on all cases. Expression of all proteins was done using immunohistochemsitry. In the radioresistant cases, 15% (six cases) showed positivity for bcl-2 and p21, respectively, and 34% (13 cases) showed mutant p53. None of the radiosensitive tumors were positive for the above proteins. 75% of the radiosensitive tumors (30 cases) were positive for the bax antibody, whereas 81% of the radioresistant tumors (31 cases) were negative for bax. The MCM2 proliferative marker was positive in > 80% of cells in 81.5% of radioresistant tumors (31 cases) as compared to < 40% of cells that were positive in 70% of radiosensitive tumors (28 cases). The P-value for the biological markers was calculated using the chi-squared test, and was highly significant (P < 0.01) for all the parameters tested. However, there was no statistical significance by univariate analysis when the dose of radiation was analyzed with respect to the markers and the histological response. There was also no correlation between the radiation response and timing of surgery. The above data strongly suggest that bax, along with proliferative markers, could play a role in determining which tumors are likely to respond to radiation therapy. The presence of bcl-2, p21 and p53 could also be related to radioresistance of the tumors.

Cyclosporin A in the treatment of refractory immune thrombocytopenia purpura in children

Patients with refractory autoimmune thrombocytopenia do not respond to standard therapy with high-dose corticosteroids, intravenous immunoglobulin, and splenectomy. We describe the cases of two patients with refractory autoimmune thrombocytopenia treated with oral cyclosporin A (CsA) to evaluate the efficacy of this alternative therapy. Blood pressure and hepatic and renal function were in the normal range before initiation of treatment. Induction therapy with pulses of high-dose methylprednisolone was used for 3 consecutive days to improve the initial immune suppression. Gradual dose reduction of CsA, according the platelet count, minimized the long-term adverse effects of CsA. Oral CsA with pulses of high-dose methylprednisolone induced remission of the thrombocytopenia. Gradual weaning of CsA over months, according the platelet count, produced no observable adverse effects of the CsA. Rapid dose reduction caused thrombocytopenia, which resolved with higher dosages of CsA. Our cases show the efficacy of CsA for refractory immune thrombocytopenia. This therapeutic option with oral CsA as an additional salvage option may avoid splenectomy and the adverse effects of long-term corticosteroids. Larger clinical investigations are necessary to establish the indications and therapeutic regimen for CsA in immune thrombocytopenia.

Anatomical risk factors for phonological dyslexia

Successful behavioral genetic studies require precise definition of a homogenous phenotype. This study searched for anatomical markers that might restrict variability in the reading disability phenotype. The subjects were 15 college students (8 male/7 female) diagnosed with a reading disability (RD) and 15 controls (8 males/7 females). All subjects completed a cognitive and reading battery. Only 11 of the RD subjects had a phonological deficit [phonological dyslexia (PD): pseudo word decoding scores < 90 (27th percentile)]. Thirteen RD (9 PD) and 15 controls received a volumetric MRI scan. Four anatomical measures differentiated the PD group from the remainder of the subjects: (i) marked rightward cerebral asymmetry, (ii) marked leftward asymmetry of the anterior lobe of the cerebellum, (ii) combined leftward asymmetry of the planum and posterior ascending ramus of the sylvian fissure, and (iv) a large duplication of Heschl's gyrus on the left. When these four measures were normalized and summed, the resulting variable predicted short- and long-term phonological memory. By contrast, oral and written comprehension skills were predicted by a different anatomical variable: low cerebral volume. These findings provide neurobiological support for an RD phenotype characterized by phonological deficits in the presence of normal or superior comprehension. The study of individual variation in cortical structure may provide a useful link between genotype and behavior.

CDC HIV prevention indicators: monitoring and evaluating HIV prevention in the USA

OBJECTIVE

This study selected and field tested indicators to track changes in HIV prevention effectiveness in the USA.

METHODS

During 1996-1999, the Centers for Disease Control and Prevention held two 2 day expert consultations with more than 80 national, state and local experts. A consensus-driven, evidence-based approach was used to select 70 indicators, which had to be derived from existing data, available in more than 25 states, and meaningful to state health officials in monitoring HIV. A literature review was performed for each indicator to determine general relevance, validity, and reliability. Two field tests in five US sites determined accessibility, feasibility, and usefulness.

RESULTS

The final 37 core indicators represent four categories: biological, behavioral, services, and socio-political. Specific indicators reflect the epidemic and associated risk factors for men who have sex with men, injection drug users, heterosexuals at high risk, and childbearing women.

CONCLUSIONS

Despite limitations, the indicators sparked the regular, proactive integration and review of monitoring data, facilitating a more effective use of data in HIV prevention community planning.

Applications of pharmacogenetics to drug development: the Glaxo Wellcome experience

The Genetics Directorate was established at Glaxo Wellcome (GW) in 1997. The goals of the Directorate are to identify susceptibility genes for common diseases with large unmet therapeutic need, apply genetic methods for the targeted development of medicines so that the right medicine is developed for the right patient, assist in translating gene discoveries into target selection, and represent genetics accurately internally within GW and externally (to laypersons, the medical community, the business community, government representatives, and regulatory agencies). As part of the goal of developing the right medication for the right patient, GW has added genetic research to its clinical drug studies in every major therapeutic area. GW worked closely with international ethicists experienced in the area of genetic research to develop the process and documents that are currently in use; these undergo frequent, rigorous review in light of the changing regulatory and legal environment and the needs of clinical investigators and patients. The addition of genetic research to clinical studies was accompanied by significant education efforts within GW and for study-site personnel, ethics committees, and regulatory authorities. Feedback from all those involved is an integral part of implementing GW's genetic research and is used to fine-tune the processes and protocol and consent document templates. A recently completed review of the approval rate from ethics committees in several countries has revealed trends in EC/IRB (Ethics Committees/Institutional Review Boards) questions and concerns about genetic research. This article will focus on the lessons learned from incorporating genetic research into clinical studies at over 1,500 international sites and will include summaries of the feedback from investigators, EC/IRBs, and regulatory authorities. It also will include a discussion of the potential applications of SNP (single nucleotide polymorphism) map technologies to pharmacogenetics by increasing the ability to correlate patients' genetic information with their response to medicines.

Characteristics of women in jail and treatment orientations. A review

Women who have been incarcerated are a high-risk group for criminal recidivism, and criminal justice statistics indicate that females are increasing in numbers more rapidly than the male detainee population. According to data from epidemiologic studies, incarcerated women are often young, single, mothers from ethnic minority backgrounds who have little education and poor work histories. Mental illness, drug abuse, and risky behaviors relating to contracting HIV/AIDS are common problems among female detainees. In this report, research into characteristics of women in jail and literature relating to treatment programs for incarcerated women are reviewed. Implications relating to treatment needs, program development, and further research are discussed. A case example and treatment intervention are presented based on this review.

Affinity-based in situ product removal coupled with co-immobilization of oily substrate and filamentous fungus

In situ product removal (ISPR) involves actions taken for the fast removal of a product from the producing cell. ISPR is implemented to improve yield and productivity via minimization of product inhibition, minimization of product losses due to degradation or evaporation, and reduction of the number of subsequent downstream processing steps. Here we describe the implementation of affinity-based, specific ISPR as a crucial component of an integrative approach to problems associated with the biocatalytic production of a product exhibiting poor water solubility from an oily, water-insoluble precursor. Our integrative ISPR-based approach consists of co-immobilization of the oily substrate emulsion and the biocatalyst within bilayered alginate beads. A particulate-specific adsorbent, exhibiting high binding capacity of the product, is suspended in the reaction medium with periodical replacements. According to this approach, ISPR implementation is expected to shift the equilibration of product distribution between the co-immobilized oily substrate and the outer medium via specific product immobilization onto the added adsorbent. The product may subsequently be readily recovered via single-step final purification. This integrative approach was successfully demonstrated by the affinity-based ISPR of gamma-decalactone (4-decanolide). gamma-Decalactone was produced from castor oil via its beta-oxidation by the filamentous fungus Tyromyces sambuceus, co-immobilized with emulsified substrate within bilayered alginate beads. Product immobilization onto medium-suspended epichlorohydrin-crosslinked beta-cyclodextrin resulted in higher yield and easy pure product recovery.

A prospective randomised multicentre trial comparing 10 Fr Teflon Tannenbaum stents with 10 Fr polyethylene Cotton-Leung stents in patients with malignant common duct strictures

BACKGROUND

Stent blockage is a multifactorial process in which stent design and materials, bacteria, proteins, and bile viscosity play a role.

AIMS

To compare the patency of the 10 Fr Teflon Tannenbaum (TT) stent to that of the 10 Fr Cotton-Leung (CL) polyethylene stent with sideholes, in patients with malignant obstructive jaundice.

METHODS

Patients were recruited to this prospective multicentre randomised study if they had a newly diagnosed malignant bile duct stricture below the hilum of the liver suitable for stenting with a 10 Fr stent. Data were collected and monitored by a professional monitoring company. Primary patency was the interval between stent placement and first exchange or death without recurrent jaundice.

RESULTS

134 consecutive patients were recruited between November 1994 and June 1997; 65 were randomised to the TT stent and 69 to the CL stent. Median patency and 95% confidence intervals were 181 (59, 303) days for the TT stent and 133 (92, 174) days for the CL stent, with no significant difference between the two stents (p=0.49). Median survival and 95% confidence intervals were 115 (71, 159) days for the TT stent and 151 (112, 190) days for the CL stent, with no significant difference between the two stents (p=0.765).

CONCLUSION

Neither Teflon as a stent material nor the Tannenbaum design prolong the patency of plastic stents.

The pathology of familial breast cancer: histological features of cancers in families not attributable to mutations in BRCA1 or BRCA2

Breast cancers arising in carriers of mutations in the breast cancer susceptibility genes, BRCA1 and BRCA2, differ histologically from each other and from breast cancers unselected for a family history. However, a substantial proportion of families with multiple cases of breast cancer is not attributable to these two genes (non-BRCA1/2 families). We have now characterized the pathology of 82 breast cancers from non-BRCA1/2 families. Breast cancers in non-BRCA1/2 families were of lower grade (P = 0.0018), showed fewer mitoses (P < 0.0001), less nuclear pleomorphism (P = 0.0014), less lymphocytic infiltrate (P < 0.0001), a lesser extent of the tumor with a continuous pushing margin (P = 0.004), a lesser extent of the tumor composed of solid sheets of cells (P = 0.0047), less necrosis (P = 0.002), and wereparison with BRCA2 tumors, non-BRCA1/2 tumors were lower grade (P = 0.017) and exhibited less pleomorphism (P = 0.01) and more tubule formation (P = 0.05). In comparison with control breast cancers unselected for a family history of the disease, non-BRCA1/2 tumors were of significantly lower grade (P = 0.001), showed less pleomorphism (P = 0.0002), and had a lower mitotic count (P = 0.003). The results indicate that non-BRCA1/2 breast cancers differ histologically from both BRCA1 and BRCA2 breast cancers and are overall of lower grade. They also suggest that non-BRCA1/2 breast cancers differ from nonfamilial breast cancers, but these differences may be attributable to various types of bias.

Immunoassay for urothelial cancers that detects DNA replication protein Mcm5 in urine

Cancer-screening tests for internal organs are severely constrained by low specificity or sensitivity, cost, and morbidity. We report a non-invasive immunofluorometric assay for detection of urothelial cancers based on ectopic expression of the DNA replication protein Mcm5.

Effect of multiple doses of montelukast, a CysLT1 receptor antagonist, on digoxin pharmacokinetics in healthy volunteers

The effect of multiple oral doses of montelukast, a cysLT1 receptor antagonist, on the pharmacokinetics of oral digoxin was studied in healthy male volunteers in a randomized double-blind two-period crossover study. Subjects received 10 mg of montelukast or placebo daily for 11 days. On day 7, they received a single 0.5 mg oral dose of digoxin elixir. The pharmacokinetic parameters of digoxin (AUC0-->24' AUC0-->infinity' Cmax' tmax' t1/2) and cumulative urinary excretion over 120 hours were not affected by the multiple doses of montelukast. The 90% confidence interval for each of these parameters fell within prespecified clinically acceptable bounds. Side effects were mild and transient. This suggests that concurrent administration of montelukast and digoxin was well tolerated. Concurrent treatment with montelukast has no effect on the pharmacokinetics of digoxin.

beta-catenin signaling can initiate feather bud development

Intercellular signaling by a subset of Wnts is mediated by stabilization of cytoplasmic beta-catenin and its translocation to the nucleus. Immunolocalization of beta-catenin in developing chick skin reveals that this signaling pathway is active in a dynamic pattern from the earliest stages of feather bud development. Forced activation of this pathway by expression of a stabilized beta-catenin in the ectoderm results in the ectopic formation of feather buds. This construct is sufficient to induce bud formation since it does so both within presumptive feather tracts and in normally featherless regions where tract-specific signals are absent. It is also insensitive to the lateral inhibition that mediates the normal spacing of buds and can induce ectopic buds in interfollicular skin. However, additional patterning signals cooperate with this pathway to regulate gene expression within domains of stabilized beta-catenin expression. Localized activation of this pathway within the bud as it develops is required for normal morphogenesis and ectopic activation of the pathway leads to abnormally oriented buds and growths on the feather filaments. These results suggest that activation of the beta-catenin pathway initiates follicle development in embryonic skin and plays important roles in the subsequent morphogenesis of the bud.

Montelukast dose selection in 6- to 14-year-olds: comparison of single-dose pharmacokinetics in children and adults

Montelukast, an oral leukotriene-receptor antagonist, has demonstrated efficacy and tolerability for the treatment of chronic asthma in adults. A once-daily 10 mg dose (film-coated tablet) was selected as the optimal adult dose based on dose-ranging studies. Asthma is a similar disease and is treated with the same medications in children and adults. These observations suggested that a dose of montelukast in children providing overall drug exposure (i.e., montelukast plasma concentrations) similar to that of the 10 mg film-coated tablet dose in adults would be efficacious, well tolerated, and obviate the need for separate dose-ranging studies in children. Therefore, the dose of montelukast for 6- to 14-year-old children was selected by identifying the chewable tablet dose of montelukast yielding a single-dose area under the plasma concentration-time curve (AUC) comparable to that achieved with the adult 10 mg film-coated tablet dose. Based on this approach, which included dose normalization of data from several pediatric pharmacokinetic studies, a 5 mg chewable tablet dose of montelukast was selected for use in clinical efficacy studies in 6- to 14-year-old children with asthma.

Minichromosome maintenance proteins as biological markers of dysplasia and malignancy

Dysplasia, an intermediate stage in the progression from normal tissue to neoplasia, is defined morphologically by a loss of normal orientation between epithelial cells, with changes in cellular and nuclear shape and size. However, little is known about the functional properties of dysplastic cells, including their replicative state, largely due to a lack of available biological markers. We have used novel antibodies against minichromosome maintenance (MCM) proteins to examine the proliferative status of a range of histological lesions and to characterize dysplastic cells in functional terms. Immunoperoxidase staining was used to localize the MCM proteins, components of the prereplicative complex that is essential for initiating eukaryotic DNA replication. These proteins are down-regulated in cells undergoing differentiation or quiescence and, thus, serve as specific markers for proliferating cells. In normal and some reactive tissues, MCM expression was present only in restricted proliferative compartments, consistent with our published findings in the uterine cervix. In dysplastic and malignant tissues, in contrast, MCM proteins were expressed in the majority of cells, extending to surface layers of dysplastic stratified epithelia. In carcinomas, the frequency of expression of MCM proteins showed an inverse correlation with the degree of tumor differentiation. Thus, we suggest that dysplastic cells may be characterized in functional terms as remaining in cell cycle, due to deregulation of normal controls over cell proliferation. Antibodies against MCM proteins have potential clinical applications, for example, in the assessment of tumor prognosis in histological sections and the identification of proliferating cells in clinical samples using biochemical or cytological assays.

Effect of montelukast on the pharmacokinetics and pharmacodynamics of warfarin in healthy volunteers

Montelukast, a cysteinyl leukotriene receptor antagonist, is being developed for the treatment of asthma and related diseases. This study was designed to evaluate whether montelukast at clinically used dosage levels would interfere with the anticoagulant effect of warfarin. In a two-period, double-blind, randomized crossover study, 12 healthy male subjects received a single oral dose of 30 mg warfarin on the 7th day of a 12-day treatment with montelukast, 10 mg daily by mouth, or a placebo. Montelukast had no significant effect on the area under the plasma concentration-time curves and peak plasma concentrations of either R- or S-warfarin. However, slight but statistically significant decreases in time to peak concentration of both warfarin enantiomers and in elimination half-life of the less potent R-warfarin were observed in the presence of montelukast. These changes were not considered as clinically relevant. Montelukast had no significant effect on the anticoagulant effect of warfarin, as assessed by the international normalized ratio (INR) for prothrombin time (AUC0-144 and INR maximum). The results of this study suggest that a clinically important interaction between these drugs is unlikely to occur in patients requiring concomitant administration of both drugs.

Rapid amperometric verification of PCR amplification of DNA

Amplification of an 800-base template was verified in a 10-min test on a 2-microL sample of the PCR product solution. For verification, digoxigeninylated primers and biotinylated d-UTP-16-biotin were added to the amplification solution. The resulting amplified product was digoxigeninlabeled at its 3'-end and was also labeled with multiple biotin functions along its chain. The detecting electrode was coated with an electron-conducting redox hydrogel to which anti-digoxin monoclonal antibody was covalently bound. The amplified DNA was captured by the electrode through conjugation of its 3'-digoxigenin with the antibody. Exposure to a solution of horseradish peroxidase-labeled avidin led to capture of the enzyme and switched the redox hydrogel from a noncatalyst to catalyst for H2O2 electroreduction. The switching resulted in an H2O2 electroreduction current density of 2.1 +/- 0.9 microA cm-2 in 10-4 M H2O2 at Ag/AgCl potential and at 25 degrees C.