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PubMed1998

Dosage titration of a characterized competitive exclusion culture to inhibit Salmonella colonization in broiler chickens during growout.

Broiler chicks were spray treated on the day of hatch with titrated dosages (10(6), 10(7), or 10(8) anaerobic CFU) of a characterized competitive exclusion culture (CF3) and challenged orally on day 3 with 10(4) CFU of Salmonella typhimurium. On day 10, cecal contents from control and CF3-treated chicks were cultured for S. typhimurium to determine the minimal efficacious dosage of the CF3 culture. The experiment was repeated in three replicated trials. Resistance to Salmonella cecal colonization was dosage related and progressively enhanced at the 10(7)- and 10(8)-CFU dosages compared with the 10(6)-CFU dosage. The 10(7)-CFU dosage was selected as the minimal effective dosage and evaluated for efficacy during a 43-day broiler growout study. Six hundred broilers were spray treated on the day of hatch and compared with 600 controls. One-half of the control and CF3-treated birds were challenged orally on day 3 with 10(4) CFU of S. typhimurium and designated "seeders." The remaining unchallenged birds were designated "contacts." Compared with the controls, the recovery of Salmonella cells from the ceca of the CF3-treated broilers was significantly decreased (P < 0.01) in the challenged seeders on days 21 and 43 of growout. Salmonella contamination of floor pen litter was significantly reduced (P < 0.05) in pens of CF3-treated birds compared with controls. The transmission of Salmonella cells from seeder to contact birds in the same pens was decreased significantly (P < 0.01). The results indicated that treatment of broiler chicks on the day of hatch with the 10(7)-CFU dosage of CF3 culture effectively increased resistance to S. typhimurium challenge during growout to market age.

Animals↗
PubMed2004

Lipid and apoprotein changes during atorvastatin up-titration in hemodialysis patients with hypercholesterolemia: a placebo-controlled study.

BACKGROUND: Patients with end-stage renal disease commonly present with an atherogenic lipid profile characterized by the accumulation of triglyceride-rich, apoprotein B-containing "remnant" lipoproteins, small dense low-density lipoprotein, and low levels of high-density lipoprotein. They are at increased cardiovascular risk and may benefit from drastic lipid-lowering treatment with atorvastatin, a potent, broadacting lipid regulator. This study aims to assess the effects of atorvastatin on the lipid profile in hemodialysis patients, to determine wether atorvastatin is also effective at lowering lipid levels in this particular high-risk subgroup. METHODS: In this randomized, placebo-controlled, double-blind study in hemodialysis patients with hypercholesterolemia (n = 42, mean total cholesterol 243 +/- 33 mg/dl (6.3 +/- 0.8 mmol/l)), the efficacy of 4-weekly increasing doses of atorvastatin (10 - 40 mg daily) was investigated. Lipids and apoproteins were measured in plasma and isolated lipoprotein fractions. RESULTS: Mean total cholesterol and low-density lipoprotein cholesterol progressively decreased with increasing doses of atorvastatin (total cholesterol -33%, low-density lipoprotein cholesterol -43% after 12 weeks), while high-density lipoprotein cholesterol remained unchanged. Plasma levels of apoprotein B and apoprotein E were also significantly reduced by atorvastatin 10 mg, while up-titration to 20 and 40 mg daily provided additional benefits by lowering triglycerides and apoprotein C-III. At week 12, the fraction of small dense low-density lipoprotein was significantly reduced from 23% - 18%, and apoprotein B-containing intermediate-density lipoproteins were no longer detectable. CONCLUSION: In conclusion, atorvastatin not only treated hypercholesterolemia but also favorably affected the uremic lipid profile in patients on hemodialysis. Atorvastatin 4-weekly dose escalation up to 40 mg daily was well-tolerated. Further prospective studies are needed to evaluate the impact of this improved lipid profile on morbidity and mortality.

Aged↗
PubMed2006

Trospium chloride in patients with neurogenic detrusor overactivity: is dose titration of benefit to the patients?

OBJECTIVE: To determine whether dose titration based on therapeutic response is superior to standard dosing of oral trospium chloride in patients with neurogenic detrusor overactivity and, moreover, to investigate the possible underlying causes of differences in efficacy at equal doses in some patients. PATIENTS AND METHODS: Using a double-blind approach, two groups (standard dose and adjustable dose) with a total of 80 patients were treated with trospium chloride coated tablets for a period of 3 - 5 weeks. Treatment duration and daily doses varied depending on change ofurodynamic parameters defined as therapeutic response. In Week 1, both groups started on 45 mg/day (3 x 15 mg). In the adjustable dose group, it was permissible to increase the daily dose to 90 or 135 mg/day depending on the urodynamic treatment response. In contrast, doses remained unchanged in the standard dose group although a need for dose adjustment had been recognized under the double-blind conditions. Therapeutic response was defined as improvement of at least two of the following three urodynamic parameters: bladder compliance 2 20 ml/cmH20, maximum cystometric capacity > 250 ml and maximum detrusor pressure < 40 cmH20. Changes in individual urodynamic parameters were defined as secondary efficacy variables. Primary and secondary parameters were assessed by comparing baseline values with those at the end of treatment. Therapeutic response was analyzed by using the Fisher-Yates test, and the Mann-Whitney U-test was used for secondary parameters. Trospium plasma concentration was measured to assess patient's compliance and as a tool to elucidate possible factors influencing treatment efficacy. Safety and tolerability were evaluated based on withdrawal rates and adverse events. RESULTS: Both dose groups had comparable baseline characteristics. Therapeutic response was achieved in 58% of patients in the adjustable dose group (ADG) and in 72% of those in the standard dose group (SDG, p -0.23). Clinically relevant increases in maximum cystometric capacity and bladder compliance were observed, and there was a clear decrease in detrusor pressure. After Day 7, the daily dose was increased in 52.8% of all patients in the adjustable dose group and (seemingly) in 32.5% of those of the standard dose group. Further dose escalation after Day 14 was assessed as necessary in 15% of the standard dose group and 22% of the adjustable dose group. The main changes in urodynamic parameters occurred during the first 7 days of treatment, but in some patients it takes a longer time. No statistically significant differences between plasma trospium chloride levels in the two dose groups were observed at any time, but increase of plasma concentration with higher doses became obvious when patients were differentiated to individual dose stages. In both groups, the most common treatment-related adverse event was dry mouth (ADG 35%, SDG 37%), which never led to discontinuation of treatment. Rates of other adverse events such as dry skin, dysopia, increased heart rate and gastrointestinal disorders were much lower. CONCLUSION: Generally, in patients with neurogenic detrusor overactivity daily doses of 45 mg trospium chloride can be considered as being the standard dose, and dose adjustment, e.g. due to increased body weight, might usually not be necessary. However, increased daily doses of up to 135 mg appear to be safe when prescribed in individual patients less responsive to the drug.

Administration, Oral↗
PubMed1979

Studies of metallobleomycins by electronic spectroscopy, electron spin resonance spectroscopy, and potentiometric titration.

The 1:1 bleomycin-A2-Cu(II) complex shows an absorption maximum at 595 nm (epsilon 120), circular dichroism extrema at 555 nm (delta epsilon + 1.21) and 665 nm (-0.61), and electron spin resonance (ESR) signal with g = 2.211, g = 2.055, and A = 178 x 10(-4) cm-1. The formation constant (log K = 12.630) and deprotonation constant (PKc = 3.585) of the 1:1 bleomycin-Cu(II) complex were determined by computer analysis of potentiometric data. The results of potentiometric titration also indicate that the stability of bleomycin-metal complexes is in the order Fe(II) less than Co(II) less than Ni(II) less than Cu(II) greater than Zn(II) and that these divalent metal complexes have a similar coordination environment. The bleomycin-Cu(II) complex has substantially a square-pyramidal configuration in which the secondary amine nitrogen, pyrimidine(N-1) ring nitrogen, deprotonated peptide nitrogen of histidine residue, and histidine imidazole(N-1) nitrogen coordinate to Cu(II) as planar ligand donors, and the alpha-amino nitrogen as axial donor. The specific Cu(II)-binding site of bleomycin has been compared with that of human serum albumin.

Binding Sites↗
PubMed1986

Transdermal nitroglycerin patches in angina pectoris. Dose titration, duration of effect, and rapid tolerance.

The duration of effect of transdermal nitroglycerin patches was studied in 14 patients with angina pectoris. By titrating the dose to achieve specific circulatory effects, we chose a patch size that produced a consistent fall in systolic blood pressure of 10 mm Hg or greater for each patient (10 cm2 in 7 patients, 20 cm2 in 5, and 40 cm2 in 2; releasing 5, 10, and 20 mg of nitroglycerin per 24 hours, respectively). The effects of these individualized patches were compared with those of placebo patches. Compared with placebo, nitroglycerin patches increased exercise duration to the onset of angina (257 +/- 72 compared with 383 +/- 130 seconds, p less than 0.0001) and total exercise time (338 +/- 89 compared with 456 +/- 119 seconds, p less than 0.0001) and decreased ST segment depression (1.0 +/- 0.5 compared with 0.6 +/- 0.4 mm, p less than 0.05) at 4 hours but not at 24 and 48 hours. We conclude that nitroglycerin patches do not show objective evidence of antianginal or antiischemic effects for 24 hours. Tolerance to the circulatory and antianginal effects probably develops within 24 hours of patch application.

Administration, Topical↗
PubMed1986

Use of microplate cell culture and enzyme immunoassay in titration of serum neutralizing antibody against Hochi strain of serotype 4 human rotavirus.

The tube neutralization test read by enzyme immunoassay developed by Wyatt et al. (1983) for serotype determination of human rotavirus was modified so as to use stationary cultures of MA104 cells in a microtiter plate instead of roller tube cultures. Sera obtained from different age groups were titrated for neutralizing antibody against serotype 4 human rotavirus Hochi strain by this test and the results were compared with those obtained by the plaque neutralization test. There was a good correlation between the titers obtained by the two tests and the age distribution pattern of serotype 4 neutralizing antibody was similar to those of serotype 1 and 3 antibodies previously reported.

Antibodies, Viral↗
PubMed1976

[Titration of antistreptolysin and control of its specificity in respect of percipitation reactions (author's transl)].

A method for the titration of antistreptolysin O (ASLO) is described that is assumed to be more rapid than the methods applied thus far. The authors are drawing attention to the non-specificity of this method and propose to use PRESLO which is easy to prepare and admits of quantitative evaluation, for a control of this non-specificity. Correlation between the two reactions were established by the authors in 2137 sera which was expressed mathematically and made subject to subsequent statistical evaluation.

Antistreptolysin↗
PubMedDate not supplied

A PCR-aided transcript titration assay (PATTY) to measure topoisomerase I gene expression in human tumor specimens.

UNLABELLED: Topoisomerase I (topo I) inhibitors are promising anticancer agents with demonstrated activity against a wide range of solid tumors. Quantitative information on topol mRNA levels in tumor biopsies may predict response to topo I inhibitors. MATERIALS AND METHODS: A polymerase chain reaction aided transcript titration assay (PATTY) was developed to allow quantitation of topol mRNA in small samples. Concentrations of topol mRNA in total RNA samples were estimated by RT-PCR analysis in a human small cell lung cancer (SCLC) cell line (GLC,) and its topotecan (GL2C/SK and F) and camptothecin (GL2C/Campt) resistant sublines, human non-small cell lung cancer (NSCLC) and ovarian carcinoma samples. RESULTS: Topol PATTY showed a decreased topo I mRNA level in GLC2/SK and F (4.5 pg/100 ng total RNA) and GLC,/Campt (2.2 pg/100 ng total RNA), respectively, compared to the parent cell line GLC2 (5.4 pg/100 ng total RNA). Topol protein levels as measured by Western blotting were compatible with topol mRNA levels. Median (range) topol mRNA levels were 3.23 (2.33-5.10) pg/100 ng total RNA in resected NSCLC specimen (n = 6), and 2.03 (0.54-0.95) pg/100 ng total RNA in resected ovarian cancer specimen (n = 6). CONCLUSION: We conclude that topol PATTY is a new assay that quantitates topol mRNA levels in cell lines and small tumor samples.

Blotting, Northern↗
PubMed1999

Effective treatment of secondary hyperparathyroidism in hemodialysis patients by titration of intravenous calcitriol dosage.

AIM: Effective treatment of secondary hyperparathyroidism (HPTH) with intravenous (i.v.) administration of calcitriol in hemodialysis patients. PATIENTS AND METHODS: The current study evaluates the use of i.v. calcitriol dosing in relation to the severity of the HPTH in 35 hemodialysis patients with serum phosphate < 6.5 mg/dl. Arbitrarily, patients with plasma IPTH levels (intact PTH) between 288 and 576 pg/ml (288 pg/ml = four-fold the upper normal limit) were given initially 1 microg i.v. calcitriol at the end of each dialysis (group A, n = 15). Patients with IPTH between 577 and 864 pg/ml received 2 microg i.v. calcitriol (group B, n = 10) and patients with IPTH more than 865 pg/ml were given 3 - 4 microg i.v. calcitriol (group C, n = 10). As IPTH levels decreased, the dose of i.v. calcitriol was also decreased gradually. Patients were followed-up for 4 months after the end of calcitriol treatment. RESULTS: During the i.v. calcitriol treatment period, the observed plasma IPTH concentrations compared with the baseline values were significantly lower (p < 0.01 for A and B group and p < 0.05 for C group) from the sixth month onwards in group A and C and from the third month onwards in group B. At the 12th month of follow-up, all patients being off i.v. calcitriol treatment for four months, a sharp and significant increase (p < 0.01 for group A and B and p < 0.05 for group C) of plasma IPTH was recorded in all three groups of patients. Alkaline phosphatase was also gradually decreased in all studied groups. Serum Ca and P remained unchanged in most patients. CONCLUSION: In conclusion, the study presented here demonstrates that the titration of i.v. calcitriol dosage according to the severity of HPTH is an effective and safe treatment of HPTH in chronic hemodialysis patients. It also shows that parathyroidectomy could be avoided in the majority of patients with severe HPTH, if an appropriate dose of calcitriol not aggravating hyperphosphatemia is administered.

Calcitriol↗
PubMed2000

NMR investigations of protein-carbohydrate interactions: studies on the relevance of Trp/Tyr variations in lectin binding sites as deduced from titration microcalorimetry and NMR studies on hevein domains. Determination of the NMR structure of the complex between pseudohevein and N,N',N"-triacetylchitotriose.

Model studies on lectins and their interactions with carbohydrate ligands in solution are essential to gain insights into the driving forces for complex formation and to optimize programs for computer simulations. The specific interaction of pseudohevein with N,N', N"-triacetylchitotriose has been analyzed by (1)H-NMR spectroscopy. Because of its small size, with a chain length of 45 amino acids, this lectin is a prime target to solution-structure determination by NOESY NMR experiments in water. The NMR-analysis was extended to assessment of the topology of the complex between pseudohevein and N, N',N"-triacetylchitotriose. NOESY experiments in water solution provided 342 protein proton-proton distance constraints. Binding of the ligand did not affect the pattern of the protein nuclear Overhauser effect signal noticeably, what would otherwise be indicative of a ligand-induced conformational change. The average backbone (residues 3-41) RMSD of the 20 refined structures was 1.14 A, whereas the heavy atom RMSD was 2.18 A. Two different orientations of the trisaccharide within the pseudohevein binding site are suggested, furnishing an explanation in structural terms for the lectin's capacity to target chitin. In both cases, hydrogen bonds and van der Waals contacts confer stability to the complexes. This conclusion is corroborated by the thermodynamic parameters of binding determined by NMR and isothermal titration calorimetry. The association process was enthalpically driven. In relation to hevein, the Trp/Tyr-substitution in the binding pocket has only a small effect on the free energy of binding in contrast to engineered galectin-1 and a mammalian C-type lectin. A comparison of the three-dimensional structure of pseudohevein in solution to those reported for wheat germ agglutinin (WGA) in the solid state and for hevein and WGA-B in solution has been performed, providing a data source about structural variability of the hevein domains. The experimentally derived structures and the values of the solvent accessibilities for several key residues have also been compared with conformations obtained by molecular dynamics simulations, pointing to the necessity to further refine the programs to enhance their predictive reliability and, thus, underscoring the importance of this kind of combined analysis in model systems.

Amino Acid Sequence↗
PubMed1999

Comparison of two colorimetric assays to determine viral infectivity in micro culture virus titration.

Efficacy of two colorimetric assays, viz. MTT (3-4,5-dimethylthiazol-2-(yl-2,5-diphenyl tetrazolium bromide) and neutral red (NR) assays, performed by integrating them to micro culture virus titration (MCVT), was compared with the conventional MCVT method in terms of percentages of infectivity and 50% infectivity end points by employing Polio virus type-3 and Dengue virus type 4 as the candidate viruses. The results suggested that MTT assay has an edge over NR assay as well as conventional MCVT method. For the first time, NR assay has been successfully employed for the determination of virus infectivity titre.

Animals↗
PubMed2000

A long-term randomized, cross-over comparison of auto-titrating and standard nasal continuous airway pressure.

This study is a 12-week randomized, cross-over, single-blind comparison of the tolerance, compliance, and symptomatic improvement obtained with standard nasal continuous positive airway pressure (CPAP) vs. an auto-titrating, self-adjusting device (APAP). Sixty newly diagnosed patients, 53 with obstructive sleep apnea (OSA) and seven with upper airway resistance syndrome were studied. Thirty-nine patients (65%) completed the 24-week protocol. Data were complete in 33. In these 33 patients CPAP and APAP reduced the Epworth Sleepiness score from 15+/-1 (+/-SEM) to 8+/-1 and 9+/-1 respectively (both <0.0001 from baseline but NS between modes). The APAP average pressure was lower than the CPAP pressure, 6.4+/-0.4 and 10.6+/-0.4 cm H20, respectively. The average daily machine use was greater with APAP, 6.0+/-0.3 hrs. versus 5.5+/-0.3 hrs. with CPAP (P < 0.04). The number of days of machine use, and the pattern of use were not different between CPAP and APAP. A higher proportion of patients who did not complete the study was randomized to CPAP for their initial treatment period. This study showed that: 1) CPAP and APAP produced an equivalent improvement in daytime sleepiness, 2) APAP pressure was lower than CPAP pressure, 3) patients wore the APAP device longer during nights they used the pressure support system, and 4) patients who began the study with APAP were more prone to continue treatment. We conclude that APAP was better tolerated and used a greater number of hours than CPAP, but the extent of improvement in excessive daytime sleepiness was similar between the two modes of therapy.

Circadian Rhythm↗
PubMed2000

[Accelerated titration design].

To reduce the number of patients treated at low and biologically inactive doses in phase I trials of anticancer agents, attempts to decrease the number of patients per dose level and to conduct a larger dose escalation have been made. Among them, accelerated titration designs were proposed and evaluated by simulation; designs 2 and 4 were reported to be acceptable (J Natl Cancer Inst 89: 1138-1147, 1997). Both designs 2 and 4 included only one patient per cohort during the initial accelerated phase. Dosage steps for the accelerated phase were defined using the modified Fibonacci method for design 2 and 100% escalation for design 4, respectively. The accelerated phase continued until one patient experienced dose-limiting toxicity or two patients experienced grade 2 toxicities. Dose escalation was conducted based on the information from the first course in design 2 and from the first three courses in design 4. In the simulation, both designs successfully reduced the total number of patients and the number of undertreated patients without increasing the number of overtreated patients. However, the safety of design 4 was assured as long as all patients received three courses of chemotherapy, which is unusual in phase I studies in Japan. Decision-making on dose escalation based on the information on toxicity in three courses might be cumbersome. Therefore, in Japan, design 2 would be recommended among the proposed accelerated designs. The performance of the design should be investigated by applying it to actual phase I studies and by evaluating the number of undertreated and overtreated patients.

Antineoplastic Agents↗
PubMedDate not supplied

Validation of a polymerase chain reaction aided transcript titration assay (PATTY) for topoisomerase II in lung cancer samples.

This report describes the validation of a polymerase chain reaction aided transcript titration assay (PATTY) for tumor samples. The results obtained with the PATTY were compared to those of RNase protection in a set of 7 human lung cancer cell lines and in 23 non-small cell lung cancer samples derived from resected patients. Whereas between PATTY and RNase protection assay a good correlation was observed in the cell lines (r = 0.74, p = 0.057), no correlation was observed within the tumor samples (r = 0.06, p = 0.78). This was also the case when only tumors with a high percentage of tumor cells (> 90%) were selected. Although PATTY is a valuable tool to measure mRNA expression in cell lines, our results caution the use of PATTY in human tumor samples without proper validation. The possible causes of these results are discussed.

Antigens, Neoplasm↗
PubMed2001

A short-term, multicenter, randomized double-blind dose titration study of the efficacy and anticholinergic side effects of transdermal compared to immediate release oral oxybutynin treatment of patients with urge urinary incontinence.

PURPOSE: We compared the short-term efficacy, safety and tolerability of transdermal versus oral oxybutynin in adults with urge urinary incontinence. MATERIALS AND METHODS: Volunteers with detrusor instability currently responding to oral immediate release oxybutynin were enrolled in our study. Those patients presenting with recurrence of incontinent symptoms after a 2-week washout underwent confirmatory cystometrogram with subsequent randomization to transdermal or oral treatment. Matching active and placebo medications included matrix patches applied twice weekly and capsules taken 2 or 3 times daily. Dose titration was based on anticholinergic symptoms. Outcome measures included comparison of baseline to 6 week changes in incontinence episodes on a 3 day urinary diary, a visual analog scale for efficacy and anticholinergic symptoms reported on a questionnaire. Safety monitoring included adverse events and skin tolerability of the transdermal system. RESULTS: A total of 76 patients were enrolled and 74 completed at least 4 weeks of treatment. Mean age in the transdermal and oral groups was 64 and 63 years, and 87% and 97% were female, respectively. Daily incontinent episodes decreased in the transdermal and oral groups (7.3 to 2.4 [66%] and 7.4 to 2.6 [72%], respectively, p = 0.39). The visual analog scale reduction in urinary leakage improved from washout in both groups (p <0.0001) with no difference between them (p = 0.9). Dry mouth occurred in significantly fewer patients in the transdermal (38%) compared with those in the oral group (94%, p <0.001). Of the patients in the transdermal group 67% noticed a reduction in dry mouth severity compared with previous oral treatment, and 90% had none or mild skin erythema. CONCLUSIONS: Transdermal delivery of oxybutynin resulted in comparable efficacy and a significantly improved anticholinergic side effect profile compared with oral administration in adults with urge urinary incontinence.

Administration, Cutaneous↗
PubMed2001

Making cool drugs hot: isothermal titration calorimetry as a tool to study binding energetics.

Characterization of the thermodynamics of binding interactions is important in improving our understanding of bimolecular recognition and forms an essential part of the rational drug design process. Isothermal titration calorimetry (ITC) is rapidly becoming established as the method of choice for undertaking such studies. The power of ITC lies in its unique ability to measure binding reactions by the detection of the heat change during the binding interaction. Since heat changes occur during many physicochemical processes, ITC has a broad application, ranging from chemical and biochemical binding studies to more complex processes involving enthalpy changes, such as enzyme kinetics. Several features of ITC have facilitated its preferential use compared to other techniques that estimate affinity. It is a sensitive, rapid, and direct method with no requirement for chemical modification or immobilization. It is the only technique that directly measures enthalpy of binding and so eliminates the need for van't Hoff analysis, which can be time consuming and prone to uncertainty in parameter values. Although ITC has facilitated the measurement of the thermodynamics governing binding reactions, interpretation of these parameters in structural terms is still a major challenge.

Calorimetry↗