Timing of re-dosing based on population pharmacokinetic-pharmacodynamics target attainment analysis of cefmetazole in subjects undergoing lower gastrointestinal surgery.

INTRODUCTION: This study was conducted to evaluate the population pharmacokinetics of prophylactic cefmetazole sodium (CMZ) based on the serum concentrations and establish a pharmacodynamics target concentration exceeding the minimum inhibitory concentration (MIC) to design the re-dosing interval. METHODS: Serum (n = 362) samples from 107 individuals were analyzed using a nonlinear mixed-effects model. The pharmacodynamics index obtained was regarded as the probability of maintaining CMZ serum trough exceeding the minimal inhibitory concentration (MIC) of 2 mg/L. This MIC was chosen to account for methicillin-susceptible Staphylococcus aureus (MSSA), E. coli, and Klebsiella pneumoniae RESULTS: The final population pharmacokinetic model was a two-compartment model with linear elimination. Creatinine clearance and body weight were identified as significant covariates influencing the central clearance and volume of distribution in the central compartment. The probability of achieving serum concentrations exceeding the MIC90 for MSSA, E. coli, and Klebsiella pneumoniae for a 1 g dose with a 10 min intravenous infusion was above 90% except for good renal function (CLcr â‰§ 95 mL/min) at 2 h after the initial dose. For patients with good renal function (CLcr â‰§ 95 mL/min), a CMZ of 2 g re-dosing interval seemed necessary to meet the achievement probability. In patients with impaired renal function (CLcr ≤20 mL/min), the probability of achievement exceeded 90% even when the dosing interval was extended to 8 h. CONCLUSIONS: We evaluated re-dosing intervals based on the population pharmacokinetics. Re-dosing intervals should be determined based on renal function.

Population Pharmacokinetic and Pharmacodynamic Target Attainment Analysis of Cefazolin in the Serum and Hip Joint Capsule of Patients Undergoing Total Hip Arthroplasty.

The objectives of this study were to evaluate the population pharmacokinetics of prophylactic cefazolin (CFZ) from its serum and hip joint capsule concentrations in patients undergoing total hip arthroplasty and to establish the pharmacodynamic target concentration exceeding the MIC for designing an effective dosing regimen for serum and the hip joint capsule. We analyzed 249 serum samples and 125 hip joint capsule samples from 125 individuals using a nonlinear mixed-effects model. The pharmacodynamic index target value obtained from our results indicates the probability of maintaining CFZ trough and hip joint capsule concentrations exceeding the MIC of 1 mg/liter to account for methicillin-susceptible S. aureus (MSSA). We estimated the population pharmacokinetics using a two-compartment model. The estimated population pharmacokinetic parameters were as follows: clearance (CL) (liters/h) = 1.46 × (creatinine clearance [CLcr] [ml/min]/77)0.891, volume of distribution of the central compartment (Vc) (liters) = 7.5, central-hip joint capsule compartment clearance (Q) (liters/h) = 3.38, and volume of distribution in the hip joint capsule compartment (VJC) (liters) = 36.1. The probability of achieving concentrations exceeding the MIC90 for MSSA was approximately 100% for serum and 100% for the hip joint capsule at 3 h after the initial dose. Our findings suggest that population-based parameters are useful for evaluating CFZ pharmacokinetics and that individual dosages should be determined based on the dosage regimen that achieves and maintains adequate tissue CFZ concentration.

Pleomorphic Carcinoma of the Lung: Relationship Between CT Findings and Prognosis.

OBJECTIVE: The objective of our study was to assess the radiologic and clinical findings of pleomorphic carcinoma (PC) of the lung and to evaluate whether there are any characteristic features that can be used to predict prognosis. MATERIALS AND METHODS: Forty-four consecutive patients whose diagnosis of PC was histologically confirmed through resection of the lung tumor were included in this study. The clinical and CT findings of these patients were retrospectively reviewed. Two thoracic radiologists evaluated the CT findings including the size, location, internal characteristics, and margin characteristics of the tumors and the presence of chest wall invasion, mediastinal invasion, and surrounding lung abnormalities. A multivariate analysis by the Cox proportional hazards regression model was used to identify variables that can be used to predict overall survival and disease-free survival. RESULTS: In the patients with PC, a central low-attenuation area or cavity (40/44, 91%), chest wall invasion (19/44, 43%), and pulmonary emphysema (30/44, 68%) were frequently observed on CT. On multivariate analysis, a massive central low-attenuation area or cavity (> 25% of the lesion) on CT indicating necrosis was the only significant independent factor for overall survival and disease-free survival (p < 0.05). Clinical findings, the presence of lymph node metastasis at surgery, and postoperative pathologic stage were not significant predictors of overall survival and disease-free survival. CONCLUSION: A massive central low-attenuation area or cavity on CT was the only predictor of overall survival and disease-free survival in patients with lung PC.

An in vitro study of metformin adsorption to activated charcoal.

INTRODUCTION: Metformin is a biguanide used to manage patients with type 2 diabetes mellitus. However, metabolic acidosis with an elevated lactate concentration and death caused by metformin overdoses are toxicological concerns. Although activated charcoal has been widely used for gastrointestinal decontamination in cases of acute poisoning, there is no evidence regarding its efficacy in treating metformin overdoses. We therefore evaluated the adsorptive capacity of activated charcoal for metformin in vitro. METHODS: Activated charcoal (specific surface area: 1,080 m2/g) mixed with various concentrations of metformin solution was dissolved in simulated gastric and intestinal fluids at 37° Celsius. The suspension was then filtered and the metformin concentration in the filtrate was determined using high-performance liquid chromatography. The maximum adsorptive capacity for metformin was calculated using the Langmuir adsorption isotherm equation. RESULTS: The amount of metformin adsorbed per gram of activated charcoal ranged from 0.7 to 8.1 mg/g at pH 1.2, and from 8.4 to 48.2 mg/g at pH 6.8. The corresponding maximum adsorptive capacities were 10.6 mg/g and 55.9 mg/g respectively. DISCUSSION: The maximum adsorptive capacity of activated charcoal for metformin was similar to that of its capacity for other poorly adsorbed substances. This is likely because metformin is water-soluble and has high polarity-factors that correlate with poor adsorption on activated charcoal. CONCLUSIONS: The maximum adsorption of metformin by activated charcoal was low. Therefore, activated charcoal may not be effective for treating patients with metformin overdose.

Evaluation of renal adverse effects of combination anti-retroviral therapy including tenofovir in HIV-infected patients.

PURPOSE: In order to maintain plasma HIV-RNA concentration in HIV-infected patients, below the detection limit combination anti-retroviral therapy (cART) are used. Although the nucleoside/nucleotide reverse transcriptase inhibitor, tenofovir disoproxil fumarate (TDF) is a first-line drug commonly used, it is associated with renal dysfunction. Nevertheless, only few clinical studies have focused on TDF in combination with new anti-HIV drugs, including the protease inhibitor (PI) darunavir (DRV), or the integrase strand transfer inhibitor (INSTI) raltegravir (RAL). Here we report the influence of such cART involving TDF on renal function. METHODS: We retrospectively investigated 68 patients under cART that included TDF between November 2004 and May 2012. We used hospital records to establish each patient's background and characteristics, CD4 cell count, plasma HIV-RNA concentration, drug combinations, renal function, and anti-retrovial therapy history. RESULTS: In all patients who had received cART, the plasma HIV-RNA concentration had fallen to less than 40 copies/mL by week 24 after the start of the therapy, and an increase in the CD4 cell count was observed. For each drug used in combination with TDF, the plasma HIV-RNA concentration and CD4 cell count showed a similar trend. After week 12, the estimated glomerular filtration rate (eGFR) had significantly decreased in all patients. The eGFR was significantly lower in those received PI on week 24 and in those received INSTI on week 12. The eGFR was significantly reduced in PI group who received atazanavir + ritonavir (ATV/RTV) on week 60. The eGFR in the DRV/RTV group tended to decrease. The eGFR in the PI and ATV/RTV group was significantly lower than in the efavirenz (EFV) group on week 96. CONCLUSION: It selecting drugs to include in combination therapy of HIV-infected patients, consideration should be given to the risk of renal dysfunction. There is a need to monitor renal function when TDF is combined with ATV/RTV, DRV/RTV or RAL.

Association of serum and fat tissue antibiotic concentrations with surgical site infections in lower gastrointestinal surgery.

BACKGROUND: During surgery, the effectiveness of perioperative prophylactic antibiotic administration against surgical site infections is inferred from serum concentrations and not from tissues where local infections occur. This study aimed to measure the serum and tissue concentrations of cefmetazole in colorectal surgery cases to clarify whether there is an association between the incidence of surgical site infections and antibiotic concentrations. METHODS: This prospective cohort study was performed at a single tertiary care center. The data of 105 patients who underwent colorectal surgery between October 2017 and September 2019 were evaluated. The primary outcome was the incidence of surgical site infections. Univariate analysis was performed to investigate the association between surgical site infections, perioperative factors, and the serum and tissue concentrations of cefmetazole. RESULTS: The incidence of surgical site infections was 13/105 (12.4%). Cefmetazole concentrations were measured at initial incision (serum; 101 vs 93.1 mg/L, P = .75, subcutaneous fat tissue; 2.8 vs 3.7 mg/g, P = .15), intestinal resection (serum; 35.1 vs 36.7 mg/L, P = .63, mesenteric adipose tissue; 1.3 vs 1.7 mg/g, P = .55), and at skin closure (serum; 34.5 vs 44.8 mg/L, P = .18, subcutaneous fat tissue; 1.0 vs 2.2 mg/g, P = .09). In univariate analysis with P ≤ .10, cefmetazole concentration in subcutaneous fat tissue at skin closure was found to be a significant risk factor for surgical site infections. Age, additional intraoperative administration of cefmetazole, and creatinine clearance were also significant risk factors for the occurrence of surgical site infections. CONCLUSION: Low subcutaneous fat cefmetazole concentrations at skin closure during gastrointestinal operations may also be involved in the occurrence of surgical site infections.

Cerebrospinal fluid leakage in intracranial hypotension syndrome: usefulness of indirect findings in radionuclide cisternography for detection and treatment monitoring.

PURPOSE: To evaluate indirect findings of cerebrospinal fluid (CSF) leakage on radionuclide cisternography and their changes after treatment. MATERIALS AND METHODS: This study was approved by the hospital's institutional review board and informed consent was obtained before each examination. A total of 67 patients who were clinically suspected of spontaneous intracranial hypotension (SIH) syndrome underwent radionuclide cisternography, and 27 patients who had direct findings of CSF leakage on radionuclide cisternography were selected for this evaluation. They were 16 males and 11 females, aged between 26 and 58 years. Sequential images of radionuclide cisternography were acquired at 1, 3, 5, and 24 hours after injection. We assessed the presence or absence of 4 indirect findings; early visualization of bladder activity, no visualization of activity over the brain convexities, rapid disappearance of spinal activity, and abnormal visualization of the root sleeves. Changes of the direct and indirect findings after treatment were also evaluated in 14 patients who underwent epidural blood patch treatment. RESULTS: Early visualization of bladder activity was found in all 27 patients. Seven of 27 (25.9%) patients showed no activity over the brain convexities. Rapid disappearance of spinal activity and abnormal root sleeve visualization were present in 2 (7.4%) and 5 (18.5%) patients, respectively. After epidural blood patch, both direct CSF leakage findings and indirect findings of early visualization of bladder activity had disappeared or improved in 12 of 14 patients (85.7%). The other indirect findings also disappeared after treatment in all cases. CONCLUSION: Indirect findings of radionuclide cisternography, especially early visualization of bladder activity, may be useful in the diagnosis and posttreatment follow-up of CSF leakage.

LH-induced neuregulin 1 (NRG1) type III transcripts control granulosa cell differentiation and oocyte maturation.

Epidermal growth factor (EGF)-like factors [amphiregulin (AREG), betacellulin, and epiregulin] are induced by LH and activate the EGF receptor (ERBB1)/ERK1/2 pathway in granulosa cells and cumulus cells of preovulatory follicles to impact ovulation. However, the expression and roles of other ERBB family members and their ligands have not been explored in detail. Herein, we document that two transcripts of the neuregulin (Nrg1) gene are expressed in granulosa cells, and that the type III Nrg1 is induced during ovulation in an ERK1/2 and C/EBPß-dependent manner. Western blotting shows that intact (75 kDa) and secreted (45 kDa) forms of neuregulin 1 (NRG1) are present in the ovary. NRG1 likely binds to ERBB3/ERBB2 complexes that are expressed in granulosa cells and cumulus cells. In cultured granulosa cells, NRG1 selectively stimulates the phosphorylation of AKT/PKB compared to ERK1/2. However, when granulosa cells were cultured with NRG1 and AREG, the phosphorylation of ERK1/2 was markedly enhanced as compared with that by AREG alone. Cotreatment with NRG1 and AREG also increased progesterone production. When cumulus-oocyte complexes (COCs) were cultured with both NRG1 and AREG, the matured oocytes exhibited significantly higher developmental competence as compared with that of oocytes cultured with AREG alone. Collectively, these results document that the expression of type III NRG1 is induced in granulosa cells during ovulation and that NRG1 enhances AREG-induced ERK1/2 phosphorylation in both granulosa cells and cumulus cells. The NRG1 pathway has two roles: one is to enhance AREG-induced progesterone production in granulosa cells, and the other is to regulate oocyte maturation by a cumulus cell-dependent mechanism.

Blood levels of catecholamine metabolites and brain-derived neurotrophic factor in a case of Sydenham's chorea.

We report a case of Sydenham's chorea with neuropsychiatric symptoms who was successfully treated with low-dose risperidone. We also longitudinally investigated serum BDNF levels and plasma levels of catecholamine metabolite in the patient. Serum BDNF levels were increased and plasma levels of HVA and MHPG were decreased according to the recovery from the active phase of the disease. These results suggest that dysfunctions of catecholaminergic neurons and neurotrophic factors might exist in Sydenham's chorea, and the decreasing catecholamine activities in response to risperidone might be associated with the improvement of the disease.