Properties of Dye-Sensitized Solar Cells Using Carbon Nanowall Counter Electrodes

This research investigates plasma-treated and metal-coated carbon nanowalls (CNWs) for use as counter electrodes of dye-sensitized solar cells (DSSCs). The CNWs were synthesized on a fluorine-tin-oxide (FTO) glass substrate using the microwave plasma-enhanced chemical vapor deposition (PECVD) system with methane (CH4) gas. The post-plasma treatment was performed on the CNWs with hydrogen (H2) plasma using PECVD, and the CNWs were sputter-coated with metal films using the RF magnetron sputtering system with a four-inch tungsten (W) target. Then the post-plasma-treated and metal-coated CNWs were used as counter electrodes for the fabrication of the DSSCs. Field-emission scanning electron microscopy (FE-SEM) was performed to obtain cross-sectional and planar images of the grown CNWs. The energy conversion efficiencies of the DSSCs manufactured using the post-plasma-treated and metal-layer-coated CNWs as the counter electrodes were measured.

Resection of a physeal bar with complete transverse osteotomy at the metaphysis and Ilizarov external fixation

The traditional techniques involving an oblique tunnel or triangular wedge resection to approach a central or mixed-type physeal bar are hindered by poor visualisation of the bar. This may be overcome by a complete transverse osteotomy at the metaphysis near the growth plate or a direct vertical approach to the bar. Ilizarov external fixation using small wires allows firm fixation of the short physis-bearing fragment, and can also correct an associated angular deformity and permit limb lengthening. We accurately approached and successfully excised ten central- or mixed-type bars; six in the distal femur, two in the proximal tibia and two in the distal tibia, without damaging the uninvolved physis, and corrected the associated angular deformity and leg-length discrepancy. Callus formation was slightly delayed because of periosteal elevation and stretching during resection of the bar. The resultant resection of the bar was satisfactory in seven patients and fair in three as assessed using a by a modified Williamson-Staheli classification.

What Should Be Considered to Cause the Early Post-Craniotomy Seizure: Antibiotics (Cefazolin) Irrigation

Objective

Post-craniotomy seizure (PCS) is reported only rarely. However, our department noted a 433% increase in PCS for a year beginning September 2010, especially after cerebrovascular surgery. Our goal was to identify the cause of our unusual outbreak of PCS.

Methods

For almost one year after September 2010, cases of PCS increased significantly in our department. We analyzed 973 patients who had received a major craniotomy between January 2009 and November 2011. We included seizures that occurred only in the first 24 postoperative hours, which we defined as early PCS. After verifying the presence of PCS, we analyzed multiple seizure-provoking factors and their relation to the duration and character of seizure activity.

Results

Overall PCS incidence was 7.2% (70/973). Cefazolin (2 g/L saline) was the antibiotic drug used for intraoperative irrigation in 88.4% of the operations, and no PCS occurred without intraoperative cefazolin irrigation. When analyzed by operation type, clipping surgery for unruptured aneurysms was the most frequently associated with PCS (80%). Using logistic regression, only 2 g cefazolin intraoperative irrigation (p=0.024) and unruptured aneurysm clipping surgery (p<0.001) were associated with early PCS. The seizure rate of unruptured aneurysm clipping surgery using 2 g cefazolin intraoperative irrigation was 32.9%.

Conclusion

Intraoperative cefazolin irrigation must be avoided in patients undergoing craniotomy, especially for clipping of unruptured aneurysms, because of the increased risk of early PCS.

Artefacts at a glance: differentiating features of artefactual stenosis from true stenosis at the genu of the petrous internal carotid artery on TOF MRA

AIM

To investigate the distinguishing features of artefactual stenosis from true stenosis at the genu of the petrous internal carotid artery (ICA) on time of flight (TOF) magnetic resonance angiography (MRA).

MATERIALS AND METHODS

Both TOF MRA and digital subtraction angiography (DSA) were performed in 65 patients with 74 vessels who demonstrated artefactual stenosis in 43 patients with 50 vessels and true stenosis in 22 patients with 24 vessels. The following findings of the signal loss were compared between the two groups: (1) margin, (2) darkness, (3) the presence of bilaterality, (4) the presence of tandem arterial stenosis, (5) the location of the epicentre, and (6) length.

RESULTS

In five out of the six evaluated items, statistically significant differences were present between the two groups (p<0.00 in all five items). Artefactual stenosis more frequently showed signal loss with ill-defined margins (47/50), less darkness compared to the background darkness (46/50), the absence of tandem arterial stenosis (35/50), epicentre at the genu (34/50), and shorter length (2.57 ± 0.68 mm). No significant difference was noted in the presence of bilaterality of signal loss between the two groups (p=0.706).

CONCLUSION

Several MRA features can be useful for suggesting artefactual stenosis rather than true stenosis at the genu of the petrous ICA on TOF MRA.

Stent-assisted Coil Embolization of Petrous ICA in a Teenager with Neurofibromatosis

We herein report on a patient with a cerebral aneurysm located at the petrous portion of the internal carotid artery (ICA). An 18-year-old male, previously diagnosed with neurofibromatosis, was referred to our emergency service complaining of severe headache, pulsatile tinnitus, nausea, and vomiting which occurred suddenly. Neuro-radiological studies including computed tomography and magnetic resonance imaging of the cerebral artery showed a large aneurysm arising from the petrous segment of the left ICA. He was treated with a neuro-interventional technique such as intra-arterial stenting and coil embolization for the aneurysm. Several days after the interventional treatment, his symptoms were resolved gradually except for a mild headache. Symptomatic unruptured aneurysm at the petrous portion of the ICA is rare, and our patient was treated successfully using a neuro-intervention technique. Therefore, we describe a case of a petrous aneurysm treated with endovascular coils without compromising the ICA flow, and review the literature.

Modified anterograde pedicle advancement flap in fingertip injury

Soft tissue reconstruction is needed to maintain the maximum length of the fingers in fingertip injury. The purpose of this study was to present an anterograde pedicle advancement flap technique, for the treatment of fingertip injuries, which involved a modification to the anterograde advancement flap by the dissection of the digital nerve and artery with a pedicle to advance the flap. This technique was used in 12 fingers in patients who had undergone soft tissue reconstruction of fingertip injuries between January 2012 and October 2013. The sizes of the flaps ranged from 8 × 7 mm to 14 × 10 mm. The mean length of advancement was 9.7 mm (range 7-13). The mean value of the static two-point discrimination test of the healed flaps was 5.1 mm (range 4-6) and the flaps survived in all the 12 cases. The modified anterograde pedicle advancement flap provides a reliable coverage of sensate soft tissue without bone shortening in fingertip injuries.Level II.

Incidence of infection according to intravenous immunoglobulin use in autologous hematopoietic stem cell transplant recipients with multiple myeloma

BACKGROUND

Although intravenous immunoglobulin (IVIG) is not routinely recommended, many centers still use IVIG during the post-hematopoietic stem cell transplant (HSCT) period.

METHOD

A total of 162 multiple myeloma (MM) patients who underwent autologous (auto-) HSCT between January 2008 and June 2013 were retrospectively reviewed. Primary objective was determination of the impact of IVIG on post-transplant infection, and secondary objectives included identification of overall incidence of infection, type of infection, and risk factors for infection after auto-HSCT in MM patients.

RESULTS

After auto-HSCT, 53 of 162 patients (32.7%) experienced 104 infectious events. Upper respiratory infection was most common (n = 31, 29.8%) and pneumonia (n = 27, 26.0%) and herpes zoster (n = 15, 14.4%) came next. Among the identifiable organisms causing respiratory infection, influenza virus (n = 10) and Pneumococcus (n = 9) were predominant. Incidence of infection was not statistically different according to IVIG use (34.8% in IVIG (-) vs. 31.3% in IVIG (+), P = 0.631). Incidence of infection requiring hospitalization and multiple episodes of infection showed no difference between the groups (P = 0.147, P = 0.156). In a Cox proportional hazard model, none of the factors including age, gender, type of disease, stage, tandem (vs. single) transplantation,and IVIG was prognostic for infectious event after auto-HSCT (P = 0.955, hazard ratio 0.980 with 95% confidence interval 0.481-1.997 for IVIG).

CONCLUSION

In auto-HSCT recipients with MM, incidence of post-transplant infection was not different according to prophylactic IVIG use.

Pontomedullary laceration, a fatal consequence of skull base ring fracture

Due to improvements in emergency resuscitation provided by rescue teams, more trauma victims who could have died due to sudden heart failure at the scene are brought to the hospital following resuscitation. Most of these patients present with major organ injuries and hypovolemic shock at the time of trauma. However, head trauma associated with sudden heart arrest is rare. Here, we report a case of ring fracture with pontomedullary laceration that led to sudden heart arrest.

A new HLA-A*30 allele, A*30:81, identified by sequence-based typing

The new allele, HLA-A*30:81, differs from A*30:01:01 by one nucleotide substitution at codon 272 (CTG→ATG).

Acetylation changes at lysine 5 of histone H4 associated with lytic gene promoters during reactivation of Kaposi's sarcoma-associated herpesvirus

Kaposi's sarcoma-associated herpesvirus (KSHV) is a pathogenic agent of Kaposi's sarcoma, primary effusion lymphoma and multicentric Castleman's disease in humans. Similarly to other gammaherpesviruses such as Epstein-Barr virus (EBV) and herpesvirus saimiri (HVS), KSHV displays two alternative life cycles, latent and lytic one. The transactivation from latency to the lytic phase is the result of transcriptional changes in the KSHV genome caused by the replication and transcriptional activator (RTA). During KSHV reactivation, epigenetic modifications of histone protein on the viral genome occur, which regulate the transcriptional activation of a number of lytic genes. The reactivation of EBV from latency to lytic cycle, induced by an immediate-early Zta protein, was shown to be accompanied by acetylation of specific lysines in histone H4. Accordingly, we hypothesized that the RTA-induced transactivation of KSHV could also be accompanied by histone acetylation. To validate this hypothesis, we assayed alterations of acetyl-histone H4-lysine 5 (acH4K5) during the RTA-mediated KSHV reactivation. While the modified histone protein in a total cell lysate was not distinguished between control and RTA-expressed cells, upregulated acH4K5 was detected on several lytic gene promoter regions during KSHV reactivation. Our results clearly indicate that this epigenetic change is related to transcription of genes expressed in the lytic cycle of KSHV.

Advanced biomatrix designs for regenerative therapy of periodontal tissues

Periodontitis is an inflammatory disease that causes loss of the tooth-supporting apparatus, including periodontal ligament, cementum, and alveolar bone. A broad range of treatment options is currently available to restore the structure and function of the periodontal tissues. A regenerative approach, among others, is now considered the most promising paradigm for this purpose, harnessing the unique properties of stem cells. How to make full use of the body's innate regenerative capacity is thus a key issue. While stem cells and bioactive factors are essential components in the regenerative processes, matrices play pivotal roles in recapitulating stem cell functions and potentiating therapeutic actions of bioactive molecules. Moreover, the positions of appropriate bioactive matrices relative to the injury site may stimulate the innate regenerative stem cell populations, removing the need to deliver cells that have been manipulated outside of the body. In this topical review, we update views on advanced designs of biomatrices-including mimicking of the native extracellular matrix, providing mechanical stimulation, activating cell-driven matrices, and delivering bioactive factors in a controllable manner-which are ultimately useful for the regenerative therapy of periodontal tissues.

Characterization and optimization of vascular endothelial growth factor(165) (rhVEGF(165)) expression in Escherichia coli

Vascular endothelial growth factors(165) (VEGF(165)) is the most potent and widely used pro-angiogenic factor. Here we determined optimal culture condition of recombinant human VEGF(165) (rhVEGF(165)) in Escherichia coli (E. coli). rhVEGF(165) expression was the highest in 0.25% of L-arabinose induction concentration, at 20 °C induction temperature, and for 5 h induction time under the control of araBAD promoter using pBADHisA vector. In biological activity test, rhVEGF(165) significantly increased the proliferative activity of CPAE cells (p<0.001) and upregulated the expressions of endothelial cell growth-related genes, such as platelet endothelial cell adhesion molecule (PECAM-1), endothelial-specific receptor tyrosine kinase (TEK), kinase insert domain protein receptor (KDR), and tyrosine kinase with immunoglobulin-like and EGF-like domains 1 (TIE1) in calf pulmonary artery endothelial (CPAE) cells.

Aberrant ventral striatal responses during incentive processing in unmedicated patients with obsessive-compulsive disorder

OBJECTIVE

Obsessive-compulsive disorder (OCD) is characterized by the dysfunction of control and reward mechanisms. However, only few neuroimaging studies of OCD have examined the reward processing. We examined the neural responses during incentive processing in OCD.

METHOD

  Twenty unmedicated patients with OCD and 20 age-, sex-, and IQ-matched healthy controls underwent functional magnetic resonance imaging while performing a modified monetary incentive delay task.

RESULTS

Compared with controls, patients with OCD showed increased ventral striatal activation in the no-loss minus loss outcome contrast and a significant positive correlation between the ventral striatal activation and compulsion symptom severity. In addition, patients with OCD showed increased activations in the frontostriatal regions in the gain minus no-gain outcomes contrast. During loss anticipation, patients with OCD showed less activations in the lateral prefrontal and inferior parietal cortices. However, during gain anticipation, patients with OCD and healthy controls did not differ in the ventral striatal activation.

CONCLUSION

These findings provide neural evidence for altered incentive processing in unmedicated patients with OCD, suggesting an elevated sensitivity to negatively affect stimuli as well as dysfunction of the ventral striatum.

Predictors of 30-day mortality and 90-day functional recovery after primary pontine hemorrhage

The factors related to death and functional recovery after primary pontine hemorrhage (PPH) in Koreans has not been well defined. The authors sought to identify independent predictors of death and functional recovery after PPH using data obtained at a single institute. Data were collected retrospectively on 281 patients with PPH admitted to the Stroke Unit at our hospital between January 1, 2000 and December 31, 2009. Multivariate logistic regression analysis was used to evaluate the associations between selected variables and 30-day mortality and 90-day functional recovery after PPH. One-hundred and ten patients (39.1%) died within 30 days of PPH and 27 patients (9.6%) achieved functional recovery within 90 days. By multivariate analysis, unconsciousness, dilated pupils, abnormal respiration, systolic blood pressure < 100 mmHg, hydrocephalus, and conservative treatment were found to be predictors of 30-day mortality, whereas consciousness, intact motor function, no history of hypertension or diabetes mellitus, intact eye movement, a hematoma volume of < 5 mL, no ventricular hemorrhage, and normally sized ventricle were found to be predictors of 90-day functional recovery. The present findings suggest that systolic hypotension of less than 100 mmHg may predict 30-day mortality and a history of underlying hypertension and diabetes mellitus may predict 90-day functional recovery.

Abstract P3-10-25: The Prognosis of Metaplastic Breast Cancer Patients Compare to Triple-Negative Breast Cancer Patients

Background: Metaplastic breeast cancer (MBC) is a rare, heterogenous cancer characterized by admixture of adenocarcinoma with metaplastic elements, low hormone receptor expression and poor outcome. This study was planned to assess the clinicopathological chacteristics and immunohistochemical findings of MBC compared to invasive ductal carcinoma (IDC) including the triple-negative subtype (TN-IDC). Material and Methods: We retrospectively reviewed the medical records of 47 MBC and 1,346 IDC patients. Two hundred eighteen TN-IDC patients were included in the 1,346 IDC patients. Between 2005 and 2009, these patients were undergone surgical treatment at the Samsung Medical Center. Patients were reviewed clinicopathologic factors, immunohistochemistry of biologic factors such as ER, PR, HER-2, p53, Ki67, cytokeratine (CK) 5/6, epidermal growth factor receptor (EGFR), and treatment modalities (type of operation, use of chemotherapy, radiotherapy and hormone therapy). Result: The MBC patients presented with a larger tumor size (&gt;T1, 66.0% vs. 44.3.%, P = 0.008), lower lymph node involvement (N0, 73.3% vs. 55.6%, P = 0.03), higher histologic (HG) and nuclear grade (NG) (HG3, 70.0% vs. 41.5%, P = 0.001; NG3,82.6% vs. 46.9%, P &lt; 0.001), fewer estrogen receptor (ER), progesterone receptor (PR) and HER2 positivity (ER+, 4.3% vs. 69.2%, P &lt; 0.001; PR+, 6.4% vs. 63.5%, P &lt; 0.001; HER2+, 0% vs. 27.6%, P &lt; 0.001), higher p53, CK5/6 and EGFR expression (p53+, 63.8% vs.38.8%, P &lt; 0.001; CK5/6+, 71.9% vs.21.5%, P &lt; 0.001; EGFR+, 93.9% vs.21.6%, P &lt;0.001) and more TN subtypes (93.6% vs. 16.2%, P &lt; 0.001) compared to the IDC group. There was no significant difference in clinicopathological characteristics with MBC and TN-IDC except EGFR over expression (EGFR+, 93.9% vs.69.0%, P = 0.017). In follow-up duration (median 30 months, range 2-56 months), seven (14.9%) MBC patients and 98 (7.2%) IDC patients recurred. The 3-year disease-free survival (DFS) rate was 78.1% in the MBC group and 91.1% in IDC group (P &lt;0.001). The 3-year DFS rate was not significantly difference between MBC group and TN-IDC group (78.1% vs. 84.9%, P = 0.114). However, in patients with lymph node metastasis who underwent adjuvant chemotherapy, the 3-year DFS rate was 44.4% in MBC group and 72.5% in TN-IDC group (P = 0.025).

Discussion: In our result, MBC show poorer clinical outcome than IDC. It is not shown significant difference between MBC and TN-IDC. However, MBC patients with nodal metastasis have poorer prognosis than TN-IDC patients with metastasis despite adjuvant chemotherapy.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-10-25.

Design and construction of a compact microwave proton source for a proton linac

A 100 MeV, 20 mA proton linear accelerator is being developed by the Proton Engineering Frontier Project at the Korea Atomic Energy Research Institute. 20 MeV acceleration system using radio frequency quadrupole and drift tube linac was already developed and has been tested. To operate this acceleration system with a long time, more reliable proton source is needed. A compact microwave proton source was proposed and has been designed and constructed as a prototype ion source for the 100 MeV proton linear accelerator. The design of microwave power injection system is based on the microwave proton injector at LANL and CEA. The wave power from a 2.45 GHz, 2 kW magnetron source is introduced into a compact plasma chamber with 7 cm diameter and 5 cm length through a standard tapered, double-ridged waveguide (WRD250) and a quartz window. The microwave power supply is installed on high voltage platform. Axial magnetic fields up to 1 kG can be provided with a water-cooled solenoid coil. A single-hole three electrode extraction system is designed for an extraction current up to 30 mA at a 50 kV extraction voltage. The design and initial operations of the proton source are presented.

Decreased phosphorylation of STAT-1, STAT-4 and cytokine release in MDR-TB patients with primary resistance

SETTING

We recently showed that treatment failure rate was higher among multidrug-resistant tuberculosis (MDR-TB) patients without a previous history of tuberculosis (TB) treatment, or so-called 'primary resistance'.

OBJECTIVE

To investigate the phosphorylation levels of signal transducers and activators of transcription-1 (STAT-1) and STAT-4 and the subsequent cytokine release as a possible cause of a poor prognosis in MDR-TB patients with primary resistance.

DESIGN

Ten patients with successfully treated pulmonary TB without resistance, 12 MDR-TB patients with acquired resistance and 10 MDR-TB patients with primary resistance were enrolled. After 24 h stimulation of peripheral blood mononuclear cells (PBMC) with interferon-gamma (IFN-gamma), interleukin-12 (IL-12), purified protein derivative (PPD), or lysate of Mycobacterium tuberculosis, flow cytometric analysis of intracellular pSTAT-1 and pSTAT-4 were performed and secretion of IFN-gamma, IL-12p40 and tumour necrosis factor-alpha (TNF-alpha) was measured in culture supernatant.

RESULTS

The mean fluorescent intensities of pSTAT-1 and pSTAT-4 in PBMC of MDR-TB patients with primary resistance decreased on stimulation of IFN-gamma, PPD or lysate of M. tuberculosis when compared with patients with acquired resistance. In addition, secretion of IFN-gamma, IL-12p40 and TNF-alpha in these patients decreased on various stimuli.

CONCLUSION

Decreased phosphorylation of STAT-1, STAT-4, and of subsequent cytokine release, might be associated with a poor prognosis in MDR-TB patients with primary resistance.

Characterization of time-related changes after experimental bile duct ligation

BACKGROUND

Although bile duct ligation (BDL) in mice is used to study cholestasis, a detailed description of this animal model is lacking. The aim of this study was to define specific phases of acute and chronic injury and repair in the different cellular compartments of the liver.

METHODS

C57BL/6 mice underwent BDL or sham laparotomy, and serum and liver tissue were analysed between 8 h and 6 weeks later.

RESULTS

Biliary infarcts and alanine aminotransferase levels revealed acute hepatocellular injury peaking at days 2-3, paralleled by enhanced transcription of pro-proliferative mediators and followed by a distinct peak of hepatocellular proliferation at day 5. Cholangiocellular proliferation occurred in large bile ducts on days 2-3 and in small bile ducts on day 5. Neutrophil infiltration occurred within 8 h, with neutrophils remaining the predominant immune cell type until day 3. Acute injury was followed by continuous tissue repair, lymphocyte and Kupffer cell infiltration, and accumulation of collagen during the second week. Thereafter, the number of alpha-smooth muscle actin-positive cells and the expression of transforming growth factor beta1, tissue inhibitor of metalloproteinases 1 and procollagen (I) decreased, and liver fibrosis stabilized.

CONCLUSION

BDL elicits dynamic changes in mouse liver. The chronological dissection and quantification of these events identified specific phases of acute and chronic cholestatic liver injury.

White matter abnormalities in drug-naïve patients with obsessive-compulsive disorder: a diffusion tensor study before and after citalopram treatment

OBJECTIVE

The aim was to investigate the white matter abnormalities of drug-naïve patients with obsessive-compulsive disorder (OCD) using diffusion tensor-imaging and the white matter changes in the patients after pharmacotherapy.

METHOD

Thirteen drug-naïve OCD patients and 13 age- and sex-matched healthy comparison subjects were examined using diffusion tensor-imaging and structural magnetic resonance imaging. Measurements were made in OCD patients before and after 12 weeks of citalopram treatment.

RESULTS

Compared with controls, the drug-naïve OCD patients showed significant increases in fractional anisotropy (FA) in the corpus callosum, the internal capsule and white matter in the area superolateral to the right caudate. The increases in FA were mostly no longer observed in patients after 12 weeks of treatment compared with controls.

CONCLUSION

Our findings suggest that white matter alterations are associated with the pathophysiology of OCD, and the abnormalities may be partly reversible with pharmacotherapy.

Characteristics of indicator microorganisms in paddy rice plots after reclaimed water irrigation

A study was performed to examine the effects of reclaimed-water irrigation on microorganism concentration in the ponded-water of paddy rice plots. Several treatments were used and each one was triplicated to evaluate the change of indicator microorganisms (total coliforms (TC), faecal coliforms (FC), and E. coli) concentrations in 2003 and 2004 growing seasons. Their concentrations increased significantly after irrigation, but decreased by approximately 45% in 24 h. It implies that agricultural activities such as ploughing and fertilising need to be practiced one or two days after irrigation, considering health risks. Treatments with UV-disinfected water irrigation, demonstrated significantly lower concentrations than others, including control plots where natural water was irrigated. The monitoring result from actual paddy rice fields and experimental paddy plots showed that concentrations of indicator microorganisms ranged from 10(2) to 10(5) MPN/100 mL. The field scale water reuse research project is in progress and national guidelines for reclaimed-water irrigation are under preparation in Korea. A comprehensive assessment of existing agricultural practices and a thorough monitoring in the fields as well as treatment plots are recommended to make national guidelines more representative.

Integrated modelling under uncertainty in watershed-level assessment and management

Uncertainty in water quality model predictions is inevitably high due to natural stochasticity, model uncertainty, and parameter uncertainty. An integrated modelling system (modified-BASINS) under uncertainty is described and demonstrated for use in receiving-water quality prediction and watershed management. A Monte Carlo simulation was used to investigate the effect of various uncertainty types on output prediction. Without pollution control measures in the watershed, the concentrations of total nitrogen (T-N) and total phosphorus (T-P) in the Hwaong Reservoir, considering three uncertainty types, would be less than about 4.4 and 0.23 mg L(-1), respectively, in 2012, with 90% confidence. The effects of two watershed management practices, wastewater treatment plants (WWTP) and constructed wetlands (WETLAND), were evaluated. The combined scenario (WWTP + WETLAND) was the most effective at improving reservoir water quality, bringing concentrations of T-N and T-P in the Hwaong Reservoir to less than 3.4 and 0.14 mg L(-1), 24 and 41% improvements, respectively, with 90% confidence. Overall, the Monte Carlo simulation in the integrated modelling system was practical for estimating uncertainty and reliable in water quality prediction. The approach described here may allow decisions to be made based on the probability and level of risk, and its application is recommended.

Acute-phase response alters the disposition kinetics of cefepime following intravenous administration to rabbits

The effect of experimentally induced fever on the pharmacokinetics of cefepime administered intravenously at a dose of 75 mg/kg bw was studied in six healthy rabbits. The study was conducted in two consecutive phases, separated by a washout period of 2 weeks. Infection was induced by the intravenous inoculation of 5 x 10(8) cfu of Escherichia coli 24 h before the pharmacokinetic investigation was carried out. Serial blood samples for cefepime concentration determination were obtained for 48 h following drug administration. The concentrations of cefepime in the plasma were determined by a quantitative microbiological assay using an agar-gel diffusion method employing Bacillus subtilis ATCC 6633 as the test organism, with a level of detectability of approximately 0.10 microg/ml. Cefepime plasma concentrations versus time were evaluated by non-compartmental methods using WinNonLin. Cefepime was well tolerated and no serious adverse events were observed. Rectal temperature increased 1 degree C 24 h post injection in infected animals. Highly significant differences in the blood plasma concentrations of cefepime were observed between febrile and healthy animals at all the sampling times. This could explain the greater area under the plasma level-time curve of the drug in febrile compared with healthy animals. The results from pharmacokinetic calculations showed that both the distribution volume at steady state (V (dss)) and body clearance (CL(tot)) were affected in febrile as compared to healthy animals. The mean values of V (dss) and CL(tot) of cefepime in healthy rabbits were 1.168 L/kg and 0.303 L/kg/h, respectively. As compared with healthy animals, the mean estimates of V (dss) (0.917 L/kg) and CL(tot) (0.205 L/kg per h) of cefepime were significantly lower, whereas t (1/2lambda), MRT and AUMC were significantly higher in febrile rabbits. It is concluded that, although experimental infection had an effect on the disposition kinetics of cefepime in healthy and febrile rabbits, this was not sufficiently pronounced to require alteration of the dosage during disease.