Toripalimab plus chemotherapy in American patients with recurrent or metastatic nasopharyngeal carcinoma: A cost-effectiveness analysis

BACKGROUND

Toripalimab, combined with gemcitabine and cisplatin, has been approved as the first-line treatment for recurrent or metastatic nasopharyngeal carcinoma (RM-NPC), representing a significant milestone as the first FDA-approved innovative therapy for this condition. Despite this achievement, there's a lack of data on the cost-effectiveness of toripalimab for RM-NPC patients in the American context.

METHODS

To assess the cost-effectiveness of toripalimab plus chemotherapy versus chemotherapy alone, a 3-state partitioned survival model was constructed. The study involved participants with characteristics matching those in the JUPITER-02 trial. Cost and utility inputs were collected from literature. Main outcomes measured were quality-adjusted life year (QALY), and incremental cost-effectiveness ratio (ICER). Univariate and probabilistic sensitivity analyses, subgroup analyses, and scenario analyses were conducted to verify the robustness of results.

RESULTS

The study found that the toripalimab regimen resulted in 4.390 QALYs at a cost of $361,813, while the chemotherapy-only regimen yielded 1.685 QALYs at a cost of $161,632. This translates to an ICER of $74,004/QALY, below the willingness-to-pay threshold of $150,000/QALY. Sensitivity analyses indicated that utility values, discount rate, and the price of toripalimab significantly impact INMB. With an 87.10% probability of being cost-effective at a $150,000/QALY threshold, the probabilistic sensitivity analysis supports toripalimab plus chemotherapy as a viable option. Scenario analysis showed that toripalimab remains cost-effective unless its price increases by 125%. Additionally, a simulated 15-year study period increases the ICER to $88,026/QALY. Subgroup analysis revealed ICERs of $76,538/QALY for PD-L1 positive and $70,158/QALY for PD-L1 negative groups.

CONCLUSIONS

Toripalimab in combination with chemotherapy is likely to be a cost-effective alternative to standard chemotherapy for American patients with RM-NPC. This evidence can guide clinical and reimbursement decision-making in treating RM-NPC patients.

Economic evaluation of olmesartan/amlodipine fixed-dose combination for hypertension treatment in China

Objectives: To evaluate the cost-effectiveness of olmesartan/amlodipine fixed-dose combination vs olmesartan and amlodipine free combination, amlodipine single drug, and valsartan/amlodipine fixed-dose combination in the treatment of hypertensive patients from payer perspective in China.Methods: A Markov model was constructed, which included five health states of hypertensive patients who are aged 35-84 years at baseline and free of cardiovascular disease. Clinical data were obtained from a network meta-analysis. Epidemiology data, adverse events (AEs), cost, and utility data were obtained from the literature. The cost associated with AEs was estimated based on the cost of same symptoms of hypertensive patients in an electric medical record database. The model projected quality-adjusted life years (QALYs) gained, total costs per patient in a 20-year time horizon, and incremental cost-effectiveness ratios. Probability sensitivity analyses (PSA) and one-way sensitivity analyses were conducted for the main parameters to test the robustness of the model.Results: Compared to olmesartan and amlodipine free combination, amlodipine, and valsartan/amlodipine fixed-dose combination, treatment with olmesartan/amlodipine fixed-dose combination led to fewer CVD events and deaths; resulted in an incremental cost of ¥-5,439 ($-791.36), ¥6,530 ($950.09), and ¥-1,019 ($-148.26) and gained additional QALYs of 0.052, 0.094, and 0.037 per patient, respectively. Compared with olmesartan and amlodipine free combination and valsartan/amlodipine fixed-dose combination, olmesartan/amlodipine fixed-dose combination was dominant. Compared with amlodipine alone, the incremental cost-effectiveness ratios were below the WHO recommended cost-effectiveness threshold, indicating the olmesartan/amlodipine fixed-dose combination was a cost-effective option for hypertensive patients in China. The 10-years' time horizon scenario analysis showed similar results to the 20-years' time horizon. Probabilistic sensitivity analysis and one-way sensitivity analyses showed the robustness of the model results.Conclusions: Olmesartan/amlodipine fixed-dose combination confers better health outcomes and costs less compared with olmesartan and amlodipine free combination and valsartan/amlodipine fixed-dose combination, and is cost-effective compared to amlodipine for hypertension treatment in China.

A Cost-effectiveness Analysis of Rabbit Antithymocyte Globulin Versus Antithymocyte Globulin-fresenius as Induction Therapy for Patients With Kidney Transplantation From Donation After Cardiac Death in China

PURPOSE

Induction immunosuppression therapy is used to support optimal outcomes in kidney transplantation. This study was to assess the cost-effectiveness of rabbit antithymocyte globulin (r-ATG) versus ATG-Fresenius (ATG-F) in kidney transplantation in the Chinese setting from the perspective of the health care payer.

METHODS

A 2-part survival model was developed, consisting of a short-term part and a long-term part. The short-term part analyzed the first year, using the decision tree, and consisted of the functioning transplant, acute rejection (AR), delayed graft function (DGF), dialysis, and death health states. The long-term part analyzed 2 to 5 years, using Markov model, and consisted of the functioning transplant, chronic dysfunction, recurring primary disease, dialysis, and death health states, with capture of the association between DGF and graft loss. Costs, including drug acquisition and other direct medical costs, were derived from China IQVIA database (formerly known as IMS) hospitaldatabase, chart review, and physician interviews. Clinical outcomes and utility were retrieved from published literature. The model calculated quality-adjusted life-years (QALYs) and total costs per patient. Costs and QALYs were discounted at an annual rate of 3.5%. Univariate sensitivity analysis and probability sensitivity analysis (PSA) were conducted to assess the impact of uncertainty of the variables on the results.

FINDINGS

Patients who received r-ATG had more clinical effectiveness than patients who received ATG-F mainly because of less AR, DGF, and dialysis. The incremental QALY was 0.01 over a 1-year time horizon and 0.0496 over a 5-year time horizon. R-ATG and ATG-F drug costs were ¥10,783 and ¥8409, respectively. However, the total treatment costs of the r-ATG arm were lower than the ATG-F arm because of lower costs related to DGF, AR, dialysis, and adverse events. In total, r-ATG saved ¥5423 over the 1-year and ¥7042 over the 5-year time horizon. R-ATG was dominant with lower total direct medical costs and higher QALYs compared with ATG-F. Both univariate sensitivity analysis and PSA found the robustness of the model results. PSA results indicated that r-ATG was cost-effective compared with ATG-F in 86.81% of the simulations, considering <3 times the gross domestic product per capita as the threshold.

IMPLICATIONS

From the perspective of the health care payer, r-ATG should be considered as the preferred treatment agent for induction therapy for Chinese patients undergoing kidney transplantation because of its lower overall medical costs and greater QALYs gained compared with ATG-F. The study was limited by lack of long-term efficacy data among the Chinese population and lack of comprehensive real-world higher quality costs data.

The cost-effectiveness of OM-85 in managing respiratory tract infections in China

OBJECTIVES

To demonstrate the health economic impact of OM-85, a bacterial lysates based immunostimulant, for its approved indications in China.

METHODS

A cost-effectiveness decision tree model was constructed comparing OM-85 with the best supportive care/placebo therapy for managing the acute exacerbation of chronic bronchitis and rhinosinusitis in the Chinese population. Clinical efficacy and adverse events (AE) data were included in the model based on a thorough literature review. All localized direct treatment costs, including drug cost, AE costs, and medical treatment costs for underlining diseases were included from a Chinese third party payer perspective. A Key Opinion Leaders (KOL) survey was conducted with 20 senior physicians specialized in respiratory, ENT, allergy, and immunology fields from tertiary hospitals in Beijing, Shanghai, Guangzhou, Hangzhou, Shenyang, and Wuhan to validate the local treatment costs. Incremental cost-effectiveness ratio (ICER) was calculated based on the above efficacy and cost information.

RESULTS

OM-85 is a cost-effective therapy when compared with placebo (standard care). OM-85 can treat/prevent one additional full episode exacerbation of chronic bronchitis and one additional full episode exacerbation of rhinosinusitis with only additional costs of RMB 653 and RMB 1182.84, respectively. In comparison, each acute exacerbation of chronic bronchitis will cost RMB 4510.10, and each acute exacerbation of rhinosinuisitis will cost RMB 1807.21 in a Chinese clinical management setting. One-way sensitivity analyses were performed and the ICER result was demonstrated to be consistent.

CONCLUSIONS

OM 85 reduces acute exacerbations among patients with chronic bronchitis and chronic rhinosinusitis when compared with Placebo (standard care). From a Chinese payer perspective, OM 85 is a cost-effective therapy in the clinical management of both chronic bronchitis and rhinosinusitis in the adult population.

APOBEC3 deletion polymorphism is associated with breast cancer risk among women of European ancestry

Copy number variations occur frequently in the genome and are a significant source of human genetic variation accounting for disease. Recently, we discovered a common deletion located in the APOBEC3A and APOBEC3B genes significantly associated with breast cancer in Chinese women. Investigating this locus in other populations would be an expedient way to evaluate the generalizability of the novel finding. We analyzed the APOBEC3 deletion in a large study of 3273 European-ancestry women (including 1671 breast cancer cases and 1602 controls) from the population-based Nashville Breast Health Study. All participants were genotyped using real-time qualitative PCR. Logistic regression was used to derive odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between the deletion polymorphism and breast cancer risk. The APOBEC3 deletion was observed in 12.4% of cases and 10.4% of controls. The deletion was significantly associated with breast cancer risk, with ORs and 95% CIs of 1.21 (1.02-1.43) associated with one-copy deletion and 2.29 (1.04-5.06) associated with two-copy deletion compared with women with no deletion (P for trend = 0.005). The positive association of the APOBEC3 deletion with breast cancer risk was similar for estrogen receptor-positive and estrogen receptor-negative breast cancer and was not modified by known breast cancer risk factors. Results from this study confirmed the association of the APOBEC3 deletion with breast cancer risk among women of European ancestry.

Determination of BMS-284756, a new quinolone, in mouse serum by high-performance liquid chromatography with fluorescence detection

A sensitive, simple, and accurate method for determination of BMS-284756, a novel des-F(6)-quinolone antimicrobial agent in mouse serum was developed by HPLC with fluorescence detection. Sample preparations were carried out by protein precipitation with the addition of acetonitrile, followed by evaporation of the acetonitrile to dryness. The resultant residual was then reconstituted in 0.01 M HCl and injected onto a Nucleosil 100 10 microm, C18 25 cm x 4.6 mm analytical column. The mobile phase consisted of acetonitrile-0.01 M NaH2PO4 (20:80, v/v) with 0.01 M tetrabutylammonium hydrogen sulfate. The fluorescence of the column effluent was monitored at an excitation wavelength of 290 nm and an emission wavelength of 418 nm. The assay was shown to be linear from 0.2 to 10.0 microg/ml (R2=0.998). Mean recovery was determined as 95.1%. Inter- and intra-assay precisions were <6% RSD. The HPLC method developed has been applied to determine the pharmacokinetics of BMS-284756 in a murine bacterial infection model.

Pharmacokinetic and pharmacodynamic profile of high dose extended interval piperacillin-tazobactam

A multiple-dose, open-labelled, randomized, two period crossover human volunteer study was performed (i) to describe the pharmacokinetic profile and safety profile of piperacillin and tazobactam (P/T) administered 6.0/0.75 g and 8.0/1.0 g q12h and (ii) to characterize the pharmacodynamic profile of these regimens against a variety of common targeted pathogens. Blood samples were collected after the third dose and concentrations of P/T were determined by a validated high-performance liquid chromatography assay. Pharmacokinetic profiles of P/T were determined by non-compartment analysis. Percentage time above the MIC (%T > MIC) of piperacillin was calculated for a range of MICs. In this study, no adverse events were attributed after multiple administrations of either 6.0/0.75 g or 8.0/1.0 g dose regimens. The peak concentration, half-life and area under the curve (AUC0-(0-tau)) of piperacillin were significantly different by a paired t-test (P < 0.05) between the two study regimens. The trough concentration, half-life and area under the curve (AUC0-(0-tau)) of tazobactam were substantially different from parameters reported previously for conventional regimens. The 8.0/1.0 g regimen provided 50% T > MIC for MICs < or =32 mg/L, while a similar value for the 6.0/0.75 g regimen was < or = 16 mg/L. High-dose P/T regimens with extended interval were well tolerated and provide adequate dynamic exposure for a variety of susceptible pathogens.

Pharmacodynamic assessment of gatifloxacin against Streptococcus pneumoniae

The pharmacodynamic parameters of peak serum drug concentration/MIC (peak/MIC) ratio and the area under the curve (AUC)/MIC ratio have been used to characterize in vivo drug exposure and its relationship to bacterial killing for the fluoroquinolones. Our study objectives were to describe the pharmacodynamic relationship between gatifloxacin exposure and outcome as assessed by bacterial density and survival in an immunocompromised murine thigh model of pneumococcal infection and to assess the relationship between drug exposure and these outcomes in an immunocompetent host. ICR mice were rendered neutropenic, and thigh infection was induced by intramuscular administration of 0.1 ml of 10(5) to 10(7) CFU of Streptococcus pneumoniae/ml. Mice received 1 to 5 mg of uranyl nitrate/kg of body weight at day -3 and were randomized to receive 10 to 80 mg of gatifloxacin/kg every 6 to 24 h orally, starting at 2 h postinoculation. Bacterial density studies were completed 24 h after initiation of therapy, and survival was assessed after 4 days of treatment. MICs for clinical isolates (n = 8) ranged from 0.25 to 1.0 microg/ml. Correlations were assessed between the change in bacterial density, as well as survival, and the AUC/MIC ratio, peak/MIC ratio, and the duration of time that serum drug concentration remained above the MIC. The best predictor of bacterial response was the AUC/MIC ratio for both outcome measures. There was greater efficacy, as measured by a decrease in log change in CFU as well as by survival data, in the immunocompetent mice compared to the immunocompromised mice. These data demonstrate (i) the appropriateness of the AUC/MIC ratio as a dynamic predictor of response to pneumococcal infection for the fluoroquinolones, (ii) that gatifloxacin AUC/MIC ratios of 30 to 40 appear to optimize bactericidal activity and survival in this model, and (iii) that immunocompetency of the host plays a role in efficacy.

Circulating tumor necrosis factor-alpha production during the progression of rat endotoxic sepsis

The endotoxin-mediated tumor necrosis factor-alpha (TNF-alpha) induction was investigated in a rat endotoxin septic shock model. Rats were challenged intravenously with lethal doses of endotoxin. Circulating endotoxin and TNF-alpha concentrations were measured over various times following endotoxin administration. A derivative of human immunoglobulin G, 5S-IgG, was administered at various times relative to endotoxin dosing to test its anti-endotoxin activity. Results showed that endotoxin challenge initiated substantial amounts of TNF-alpha release into the rat circulatory system leading to death. A temporal pattern of TNF-alpha increases following endotoxin administration was observed; the rat plasma TNF-alpha level rapidly increased 60 min after endotoxin injection, peaked around 120 min and returned to low levels by 240 min. A rapid clearance pattern of endotoxin was also observed in rats. 5S-IgG exhibited its moderate anti-endotoxin activity by partially suppressing the endotoxin-mediated TNF-alpha release and decreasing the overall mortality only when given before triggering of TNF-alpha induction. However, this inhibitory effect of 5S-IgG on endotoxin-mediated TNF-alpha release and the resultant protective effect against endotoxin lethality rapidly diminished when 5S-IgG was administered after the occurrence of TNF-alpha induction. Collectively, these results suggest that the timing of the anti-endotoxin treatment is critical in achieving its effectiveness and imply that the endotoxin levels after the onset of the cytokine cascade is of questionable significance.

Streptococcus pneumoniae response to repeated moxifloxacin or levofloxacin exposure in a rabbit tissue cage model

The role of moxifloxacin and levofloxacin pharmacokinetics (PK) in antimicrobial efficacy and in the selection of fluoroquinolone-resistant Streptococcus pneumoniae strains was investigated using the rabbit tissue cage abscess model. A rabbit tissue cage was created by insertion of sterile Wiffle balls in the dorsal cervical area. Animals orally received a range of moxifloxacin or levofloxacin doses that simulate human PK for 7 days 48 h after the Wiffle balls were inoculated with fluoroquinolone-sensitive S. pneumoniae (10(7) CFU). Abscess fluid was collected on a daily basis over 14 days to measure bacterial density and MICs. Moxifloxacin regimens produced a range of area under the concentration-time curve (AUC)/MIC ratios ranging from 9.2 to 444 and peak/MIC ratios ranging from 1.3 to 102. Levofloxacin doses produced AUC/MIC ratios of 5.1 to 85.5 and peak/MIC ratio of 0.9 to 14.8. Moxifloxacin at 6.5, 26, and 42 mg/kg reduced the bacterial log CFU per milliliter in abscess fluid (percentage of that in a sterile animal) by 4.2 +/- 2.2 (20%), 5.8 +/- 0.4 (100%), and 5.4 +/- 0.4 (100%), respectively, over the dosing period. Levofloxacin at 5.5, 22, and 32 mg/kg reduced the log CFU per milliliter in abscess fluid (percentage of that in a sterile animal) by 2.8 +/- 0.7 (20%), 5.1 +/- 1.3 (80%), and 4.6 +/- 1.3 (60%), respectively. Moxifloxacin has a greater bactericidal rate as determined by regression of log CFU versus time data. The AUC/MIC and peak/MIC ratios correlated with the efficacy of both drugs (P < 0.05). Resistance to either drug did not develop with any of the doses as assessed by a change in the MIC. In conclusion, data derived from this study show that moxifloxacin and levofloxacin exhibit rapid bactericidal activity against S. pneumoniae in vivo, and moxifloxacin exhibits enhanced bactericidal activity compared to levofloxacin, with AUC/MIC and peak/MIC ratios correlated with antimicrobial efficacy for both drugs. The development of fluoroquinolone-resistant S. pneumoniae was not observed with either drug in this model.

Comparison of azithromycin leukocyte disposition in healthy volunteers and volunteers with AIDS

Azithromycin, has been proved to be effective in the treatment and prophylaxis of a wide variety of infections. While the penetration of azithromycin into a number of types of mammalian cells has been well characterized, the influence of HIV infection on the intracellular disposition of this agent has not been studied. We therefore studied the disposition of azithromycin in polymorphonuclear (PMN) and mononuclear (MONO) leukocytes from six healthy volunteers and six volunteers with AIDS. After oral administration of a single 1200-mg dose of azithromycin (two 600-mg tablets), blood samples were collected over 6 days and intracellular azithromycin concentrations in MONOs and PMNs were measured. Analysis of the intracellular pharmacokinetics revealed an apparent difference in the MONO and PMN profile; this profile was similar for both groups. Intracellular concentrations of azithromycin remained high throughout the study period. Furthermore, no statistically significant differences in the intracellular area under the curve (11309+/-2543 vs. 16650+/-6254 for PMN; 14180+/-3802 vs. 21211+/-10001 for MONO) were observed between the healthy and AIDS populations, respectively. Our data confirm the extensive uptake of azithromycin by white blood cells both in healthy volunteers and in AIDS patients.

Population pharmacokinetics of tobramycin in hospitalized patients receiving once-daily dosing regimen

The population pharmacokinetics of tobramycin was investigated in a group of 327 adult hospitalized patients receiving once-daily administration of tobramycin at a dose of 7 mg kg(-1). The patients had an average age of 57+/-18 y and an average weight of 65+/-14 kg; 153 of the patients were female. Data, comprised of 575 serum concentrations, were analyzed using a nonlinear mixed-effect model (NONMEM) with a first-order conditional estimation method and were best described with a one-compartment model. The patient covariates including body weight, gender, age and creatinine clearance (CL(CR)) were added in a stepwise fashion to identify their potential influences on tobramycin pharmacokinetics. Results showed that tobramycin clearance (CL) was linearly correlated with CL(CR) (proportionality constant: 0.066+/-0.002 x CL(CR) (ml min(-1))) and the volume of distribution (Vd) was linearly related to body weight (proportionality constant: 0.40+/-0.024 x body weight (1 kg(-1))). The mean population estimates for CL and Vd were 4.53 l h(-1) and 27.3 l, respectively. The half-life of tobramycin was estimated to be 4.2 h. The inter-individual variability in CL and Vd were 37.0 and 28.5%, respectively. The residual error was 1.2 mg l(-1). Based on the results, optimal dosing intervals for renal impaired patients were calculated and were comparable with the intervals derived from the previous established nomogram.

Sources of NADPH and expression of mammalian NADP+-specific isocitrate dehydrogenases in Saccharomyces cerevisiae

To compare roles of specific enzymes in supply of NADPH for cellular biosynthesis, collections of yeast mutants were constructed by gene disruptions and matings. These mutants include haploid strains containing all possible combinations of deletions in yeast genes encoding three differentially compartmentalized isozymes of NADP+-specific isocitrate dehydrogenase and in the gene encoding glucose-6-phosphate dehydrogenase (Zwf1p). Growth phenotype analyses of the mutants indicate that either cytosolic NADP+-specific isocitrate dehydrogenase (Idp2p) or the hexose monophosphate shunt is essential for growth with fatty acids as carbon sources and for sporulation of diploid strains, a condition associated with high levels of fatty acid synthesis. No new biosynthetic roles were identified for mitochondrial (Idp1p) or peroxisomal (Idp3p) NADP+-specific isocitrate dehydrogenase isozymes. These and other results suggest that several major presumed sources of biosynthetic reducing equivalents are non-essential in yeast cells grown under many cultivation conditions. To develop an in vivo system for analysis of metabolic function, mammalian mitochondrial and cytosolic isozymes of NADP+-specific isocitrate dehydrogenase were expressed in yeast using promoters from the cognate yeast genes. The mammalian mitochondrial isozyme was found to be imported efficiently into yeast mitochondria when fused to the Idp1p targeting sequence and to substitute functionally for Idp1p for production of alpha-ketoglutarate. The mammalian cytosolic isozyme was found to partition between cytosolic and organellar compartments and to replace functionally Idp2p for production of alpha-ketoglutarate or for growth on fatty acids in a mutant lacking Zwf1p. The mammalian cytosolic isozyme also functionally substitutes for Idp3p allowing growth on petroselinic acid as a carbon source, suggesting partial localization to peroxisomes and provision of NADPH for beta-oxidation of that fatty acid.

In vitro reduction of endotoxin concentrations with the 5S fragment of immunoglobulin G

Endotoxin has long been implicated as an inducer for the development and progression of gram-negative sepsis. Accordingly, antiendotoxin therapy has been considered one of the major targets for the treatment of sepsis. To investigate the influence of a human immunoglobulin G (IgG) derivative, the 5S fragment of IgG (5S-IgG; Gamma-Venin, Centeon Pharma GmbH, Frankfurt-Niederrad, Germany), on endotoxin release during bacterial proliferation and under antibiotic bactericidal action, time-kill studies were performed by using Escherichia coli ATCC 25922 starting inocula of 10(3), 10(5), and 10(7) CFU/ml with cefotaxime (120 microg/ml) alone and in combination with 5S-IgG (2,100 microg/ml). Samples were collected for bacterial colony count and endotoxin concentration determinations; the area under the free endotoxin concentration curve (AUFEC) was calculated by using the trapezoidal rule. Colony counts showed that cefotaxime had a rapid bactericidal effect because it achieved greater than a 4-log decrease in the numbers of E. coli CFU per milliliter over the first 2 h; the addition of 5S-IgG did not appear to alter the kinetics of killing. Comparison of the AUFEC revealed that the addition of 5S-IgG resulted in a mean reduction of 50, 66, and 27% in the free endotoxin concentration at starting inocula of 10(3), 10(5), and 10(7) CFU/ml, respectively. Moreover, experiments were conducted with a starting inoculum of 10(5) CFU/ml and various amounts of 5S-IgG (2 to 20 mg/ml) to further investigate the dose-effect relation of 5S-IgG on endotoxin release. Decreased AUFECs were observed with increasing concentrations of 5S-IgG, suggesting the dose-dependent antiendotoxin activity of 5S-IgG. Further study is required to investigate the mechanism(s) responsible for this observation, the biological significance of this antiendotoxin activity, and the potential utility of 5S-IgG as an adjuvant therapy in the treatment of gram-negative sepsis.

[Applied anatomy of the medial superior genicular artery and the retrograde island flap]

Through anatomical dissection of fifty freshly amputated adult lower extremities, the origin, length, diameter and extent of perfusion of the superior genicular artery and its relation with the anterior tibial recurrent artery were investigated. Results revealed that the medial superior genicular artery originated primarily from the femoral artery (95.5%). It descends between the sartorius and majormedial muscles and then separates into branches that nourish the upper one-third of the lower leg and the medial skin of the knee, and then, by anastomosis, joins the anterior tibia recurrent artery on the level of the medial malleolus of the tibia. The formation rate of the anastomotic arch is 100% with the average outer diameter of 1.3 +/- 0.39 mm (x +/- s). Based on these observations, we conclude that the medial area of the knee is the best donor site of an island flap, which can be used to repair the medial superior one-third of the lower leg and the region around the knee.

Comparison of bronchopulmonary pharmacokinetics of clarithromycin and azithromycin

The bronchopulmonary and plasma pharmacokinetics of clarithromycin (CLA; 500 mg given twice daily for nine doses) or azithromycin (AZ; 500 mg for the first dose and then 250 mg once daily for four doses) were assessed in 41 healthy nonsmokers. Bronchoalveolar lavage was performed at 4, 8, 12, or 24 h after administration of the last dose. The concentrations (mean +/- standard deviation) of CLA, 14-hydroxyclarithromycin, and AZ were measured in plasma, epithelial lining fluid (ELF), and alveolar macrophage (AM) cells by high-performance liquid chromatography assay. The concentrations of CLA achieved in ELF were 34.02 +/- 5.16 micrograms/ml at 4 h, 20.63 +/- 4.49 micrograms/ml at 8 h, 23.01 +/- 11.9 micrograms/ml at 12 h, and 4.17 +/- 0.29 microgram/ml at 24 h, whereas at the same time points AZ concentrations remained below the limit of assay sensitivity (0.01 microgram/ml) for all but two subjects. The concentrations of CLA in the AM cells were significantly higher than those of AZ at 8 h (703 +/- 235 and 388 +/- 53 micrograms/ml, respectively). However, the ratio of the concentration in AM cells/concentration in plasma was significantly higher for AZ than for CLA for all time points because of the lower concentration of AZ in plasma. These results indicate that while AZ has higher tissue concentration to plasma ratios, as shown by other investigators, the absolute concentrations of CLA in AM cells and ELF are higher for up to 8 and 12 h, respectively, after administration of the last dose.