Investigating the effects of PTEN mutations on cGAS-STING pathway in glioblastoma tumours.

BACKGROUND: PTEN is a tumour suppressor gene and well-known for being frequently mutated in several cancer types. Loss of immunogenicity can also be attributed to PTEN loss, because of its role in establishing the tumour microenvironment. Therefore, this study aimed to represent the link between PTEN and cGAS-STING activity, a key mediator of inflammation, in tumour samples of glioblastoma patients. METHODS: Tumour samples of 36 glioblastoma patients were collected. After DNA isolation, all coding regions of PTEN were sequenced and analysed. PTEN expression status was also evaluated by qRT-PCR, western blot, and immunohistochemical methods. Interferon-stimulated gene expressions, cGAMP activity, CD8 infiltration, and Granzyme B expression levels were determined especially for the evaluation of cGAS-STING activity and immunogenicity. RESULTS: Mutant PTEN patients had significantly lower PTEN expression, both at mRNA and protein levels. Decreased STING, IRF3, NF-KB1, and RELA mRNA expressions were also found in patients with mutant PTEN. Immunohistochemistry staining of PTEN displayed expressional loss in 38.1% of the patients. Besides, patients with PTEN loss had considerably lower amounts of IFNB and IFIT2 mRNA expressions. Furthermore, CD8 infiltration, cGAMP, and Granzyme B levels were reduced in the PTEN loss group. CONCLUSION: This study reveals the immunosuppressive effects of PTEN loss in glioblastoma tumours via the cGAS-STING pathway. Therefore, determining the PTEN status in tumours is of great importance, like in situations when considering the treatment of glioblastoma patients with immunotherapeutic agents.

Impact of the empirical therapy timing on the clinical progress of septic shock patients.

AIM: To evaluate the effect of timing of antimicrobial therapy on clinical progress of patients with septic shock. MATERIALS AND METHOD: We included 204 adult patients diagnosed with septic shock according to Sepsis-3 criteria between March 2016 and April 2021. One-month survival was evaluated using univariate and logistic regression analysis. RESULTS: Antibiotic treatment was initiated within 1 h of the vasopressors in 26.4 % of patients. One-month mortality did not differ significantly between patients with and without empirical therapy coverage on etiological agents. Univariate factors that significantly affected one-month survival were starting antibiotics at the first hour, the unit where the case was diagnosed with septic shock, SOFA scores, qSOFA scores, and lactate level. In multivariate analysis, diagnosis of septic shock in the Emergency Service, SOFA score ≥11, qSOFA score of three and lactate level ≥4 were significantly associated with one-month mortality. CONCLUSION: Training programs should be designed to increase the awareness of septic shock diagnosis and treatment in the Emergency Service and other hospital units. Additionally, electronic patient files should have warning systems for earlier diagnosis and consultation.

Empirical cefepime+vancomycin versus ceftazidime+vancomycin versus meropenem+vancomycin in the treatment of healthcare-associated meningitis: results of the multicenter ephesus study.

BACKGROUND: Herein, we analyzed the efficacy of main antibiotic therapy regimens in the treatment of healthcare-associated meningitis (HCAM). MATERIALS/METHODS: This retrospective cohort study was conducted in 18 tertiary-care academic hospitals Turkey, India, Egypt and Romania. We extracted data and outcomes of all patients with post-neurosurgical meningitis cases fulfilling the study inclusion criteria and treated with empirical therapy between December 2006-September 2018. RESULTS: Twenty patients in the cefepime + vancomycin-(CV) group, 31 patients in the ceftazidime + vancomycin-(CFV) group, and 119 patients in the meropenem + vancomycin-(MV) group met the inclusion criteria. The MV subgroup had a significantly higher mean Glasgow Coma Score, a higher rate of admission to the intensive care unit within the previous month, and a higher rate of antibiot herapy within the previous month before the meningitis episode (p < 0.05). Microbiological success on Day 3-5, end of treatment (EOT) clinical success (80% vs. 54.8%% vs 57.9%), and overall success (EOT success followed by one-month survival without relapse or reinfection 65% vs. 51.6% vs. 45.3%), EOT all cause mortality (ACM) and day 30 ACM (15% vs. 22.6% vs. 26%) did not differ significantly (p > 0.05) among the three cohorts. No regimen was effective against carbapenem-resistant bacteria, and vancomycin resulted in an EOT clinical success rate of 60.6% in the methicillin-resistant staphylococci or ampicillin-resistant enterococci subgroup (n = 34). CONCLUSIONS: Our study showed no significant difference in terms of clinical success and mortality among the three treatment options. All regimens were ineffective against carbapenem-resistant bacteria. Vancomycin was unsuccessful in approximately 40% of cases involving methicillin-resistant staphylococci or ampicillin-resistant enterococci.

Tigecycline in the treatment of multidrug-resistant Acinetobacter baumannii meningitis: Results of the Ege study.

OBJECTIVES: In this study we retrospectively reviewed A. baumannii meningitis cases treated with tigecycline including regimens and evaluated the efficacy of tigecycline in the therapy. PATIENTS AND METHODS: Study was performed in seven tertiary-care educational hospitals from five cities of Turkey and one center from France. We extracted data and outcomes of all adult (aged >18) patients with culture proven A. baumannii meningitis treated with tigecycline including antibiotic therapy until April 2016. RESULTS: A total of 23 patients (15 male and eight female) fulfilled our inclusion criteria. All Acinetobacter strains were carbapenem-resistant and susceptible to tigecycline. Six cases received tigecycline monotherapy while 17 received tigecycline including combination therapy (10 with colistin, 4 with netilmicin, 3 with amikacin, 4 with meropenem). Seven of 23 cases (30%) died during the tigecycline including therapy (1 in monotherapy, 4 in colistin, 2 in netilmicin, 1 amikacin, one case received tigecycline + netilmicin followed by tigecycline + colistin). Hence, overall end of treatment (EOT) success was 70%. However, since further 27% died due to additional nosocomial infections, overall clinical success (relieved symptoms at the EOT and one-month post-therapy survival without any relapse or reinfection) decreased to 43%. CONCLUSION: We conclude that tigecycline may be an alternative in the salvage treatment of nosocomial multidrug-resistant Acinetobacter spp. meningitis. Acinetobacter spp. Meningitis.

Management of Calvarial Tumors: A Retrospective Analysis and Literature Review.

AIM: Tumors of various organs that metastasize to bone do not neglect calvarium as a target. The aim of this study was to characterize the calvarial tumors. MATERIAL AND METHODS: We retrospectively reviewed 45 consecutive patients operated for calvarial masses from January 2002 till May 2012 at our hospital. Skull base tumors and patients ≤18 years were excluded. RESULTS: Three groups of lesions were found - calvarial metastases (15/45), primary tumors (5/45) and tumor-like lesions (25/45). Malignant lesions were equitable by gender distribution, higher age of onset (median age of primary =55; secondary = 60 years) and benign lesions by younger age (median = 35) and female bias (18/25). Calvarial metastases mostly presented with local swelling (10/15), local pain (6/15) and rarely neurologic deficit. There was associated dural sinus thrombosis (4/20 of malignant; 1/25 of benign lesions) and osteolysis (3/5 primary malignant, 13/15 secondary and 18/25 of benign lesions). Complete surgical excision was possible with minimal morbidity in all except one patient and nil mortality. CONCLUSION: Nearly half (20/45) of the calvarial lesions tend to be malignant with most of them presenting as silent painless masses. Surgical excision should be considered only after suitable investigation and appropriate neurosurgical set-up.

Tigecycline in the management of post-neurosurgical spondylodiscitis: a review of eight cases.

BACKGROUND: Tigecycline is a relatively new glycylcycline antimicrobial, active in vitro against a variety of Gram-positive and Gram-negative organisms. In this study we evaluated the outcomes of spondylodiscitis cases treated with tigecycline-including therapies retrospectively. METHODS: All adult (age >18 years) cases with a diagnosis of spondylodiscitis, who were treated with a tigecycline-including therapy between 2007 and 2011, were included in the study. The primary efficacy outcome was clinical success with tigecycline at the end of induction, while the secondary efficacy outcome was maintenance of success through 3 months following completion of induction. RESULTS: A total of eight spondylodiscitis cases fulfilled the study inclusion criteria. All cases had back pain, restricted mobility, magnetic resonance findings associated with spondylodiscitis, and microbiology or pathological findings related to spondylodiscitis. All had post-neurosurgical spondylodiscitis. In five cases, tigecycline was started in accordance with the antibacterial susceptibility results from intervertebral tissue biopsy cultures, whereas in three it was started empirically. All cases had received several different antibacterials with failure before receiving tigecycline. The mean duration of tigecycline treatment was 37±21 days. One case was lost to follow-up after 2 days of tigecycline. Primary and secondary success was achieved in the remaining seven cases. CONCLUSIONS: These limited data suggest that tigecycline may have a role in the treatment of refractory spondylodiscitis cases.

Vancomycin versus linezolid in the treatment of methicillin-resistant Staphylococcus aureus meningitis.

BACKGROUND: Vancomycin is the mainstay of treatment for methicillin-resistant Staphylococcus aureus (MRSA) meningitis. However, successful outcomes with linezolid have not been reported in a large series of patients. We conducted a single-center retrospective cohort study to compare vancomycin with linezolid in the treatment of MRSA meningitis. METHODS: We extracted data and outcomes for all adult patients (age >18 years) with culture-proved MRSA meningitis who received vancomycin or linezolid between January 2006 and June 2011. A definite diagnosis of meningitis was based on the isolation of MRSA in at least one cerebrospinal fluid (CSF) culture and findings in CSF that are typical of the infection. Linezolid was given intravenously (IV) at a dosage of 600 mg q12h and vancomycin IV at 500 mg q6h. RESULTS: A total of 8 patients with MRSA meningitis (5 male, 3 female; age [mean±SD] 61.6±13.2 years) received vancomycin and 9 patients (7 male, 2 female; age 59.1±15.6 years) received linezolid. All isolated strains of MRSA were susceptible to both vancomycin and linezolid. The rates of microbiologic success with linezolid or vancomycin, in terms of clearance of MRSA from CSF on day 5, were 7/9 and 2/8 (p=0.044, Fisher exact test). No severe adverse events occurred in either treatment arm of the study. One-month survival of the patients in whom treatment was successful microbiologically was 2/2 in the vancomycin-treated group and 4/7 in the linezolid-treated group. Minimum inhibitory concentration (MIC) data for vancomycin were available for 5/6 treatment failures with vancomycin, and vancomycin MIC values of these five strains were 2 mg/L. CONCLUSION: Analysis of the findings in the limited cohorts in our study suggests that linezolid is superior to vancomycin for treating MRSA meningitis, especially in cases in which there is a high MIC (2 mg/L) for vancomycin. A clinical study involving larger cohorts may increase the evidence available in relation to this question.

Vancomycin versus linezolid in the treatment of methicillin-resistant Staphylococcus aureus meningitis in an experimental rabbit model.

BACKGROUND: The aim of this study was to compare the antibacterial efficacy of vancomycin and linezolid in a rabbit model of methicillin-resistant Staphylococcus aureus (MRSA) meningitis. MATERIAL/METHODS: Meningitis was induced by intracisternal inoculation of ATCC 43300 strain. After 16 h incubation time and development of meningitis, the vancomycin group received vancomycin 20 mg/kg every 12 h. The linezolid-10 and linezolid-20 groups received linezolid in 10 and 20 mg/kg dosages every 12 h, respectively. The control group did not receive any antibiotics. Cerebrospinal fluid bacterial counts were measured at the end of 16-h incubation time and at the end of 24-h treatment. RESULTS: Bacterial counts were similar in all groups at 16 h. At the end of treatment the decrease in bacterial counts in the vancomycin group was approximately 2 logs higher than the linezolid-20 group (p>0.05) and approximately 4 logs higher than in the linezolid-10 group (p: 0.037) (Vancomycin group: -2.860 ± 4.495 versus Linezolid-20: -0.724 ± 4.360, versus Linezolid-10: 1.39 ± 3.37). Full or partial bacteriological response was higher in vancomycin versus linezolid-10 (p: 0.01), but not vancomycin versus linezolid-20 or linezolid-10 versus-linezolid-20 groups. CONCLUSIONS: Our results suggest that linezolid is not statistically inferior to vancomycin in the treatment of MRSA meningitis in an experimental rabbit model in 20 mg/kg q12 h dosage; however, it is inferior in 10 mg/kg q12 h dosage. Additional data should gathered to confirm these findings in advance of clinical trials to assess efficacy in humans.

Linezolid in the treatment of methicillin-resistant staphylococcal post-neurosurgical meningitis: a series of 17 cases.

BACKGROUND: Linezolid is a bacteriostatic antibiotic with good cerebrospinal fluid penetration. The aim of this study was to evaluate the efficacy of linezolid in methicillin-resistant staphylococcal (methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus (MRCoNS)) meningitis. METHODS: We extracted data and outcomes for all adult patients (age > 18 y) with culture-proven MRSA or MRCoNS meningitis treated with linezolid between January 2006 and September 2010 in our hospital. Demographic, clinical, and laboratory data and predisposing factors, as well as information on response to treatment and outcome were obtained by regular visits. RESULTS: A total of 17 cases (9 MRCoNS, 7 MRSA, and 1 MRCoNS and MRSA mixed) fulfilled the inclusion criteria. All patients had hospital-acquired meningitis and had undergone neurosurgery. Cumulative microbiological success on day 5 was 88%. There was 1 staphylococcal meningitis-related death. There were no severe adverse events. CONCLUSIONS: Our experience with linezolid suggests that it can be an alternative for the treatment of MRCoNS- and MRSA-related meningitis.

Protective effects of edaravone on experimental spinal cord injury in rats.

BACKGROUND: Spinal cord injury (SCI) is a leading cause of morbidity and mortality among youth and adults. Secondary injury mechanisms within the spinal cord (SC) are well known to cause deterioration after an acute impact. Free radical scavengers are among the most studied agents in animal models of SCI. Edaravone is a scavenger of hydroxyl radicals. METHODS: We aimed to measure and compare the effects of both methylprednisolone and edaravone on tissue and on serum concentrations of nitric oxide (NO), malondialdehyde (MDA) levels, superoxide dismutase (SOD) activity, glutathione peroxidase (GSH-Px) activity, and tissue total antioxidant capacity (TAC) in rats with SCI. SCI was induced in four groups of Wistar albino rats by a weight-drop method. The neurological function of the rats was periodically tested. At the end of the experiment, blood samples were collected, and SC tissue samples were harvested for biochemical evaluation. RESULTS: The tissue level of NO was decreased in the edaravone-treated group compared with the no-treatment group (p < 0.05). The tissue levels of SOD and GSH-Px were higher in the edaravone-treated group than in the no-treatment group (p < 0.05). The serum levels of NO were lower in the edaravone-treated and methylprednisolone-treated groups than in the no-treatment group (p < 0.05). The serum levels of SOD in the edaravone-treated group did not differ from those of any other group. The serum levels of MDA in the edaravone-treated and no-treatment groups were higher than in the two other groups (p < 0.05). Tissue levels of MDA in the edaravone-treated group were lower than in the no-treatment group (p < 0.05). Tissue levels of TAC in the edaravone-treated group were higher than in the no-treatment and methylprednisolone-treated groups (p < 0.05). The neurological outcome scores of the animals in treatment groups did not depict any statistically significant improvement in motor functions. However, edaravone seemed to prevent further worsening of the immediate post-SCI neurological status. CONCLUSION: Our biochemical analyses indicate that edaravone is capable of blunting the increased oxidative stress that follows SCI. We show, for the first time, that edaravone enhances the TAC in SC tissue. This beneficial effect of edaravone on antioxidant status may act to minimize the secondary neurological damage that occurs during the acute phase after SCI.

[A case of cerebral abscess due to methicillin-resistant Staphylococcus aureus which is treated with linezolid + rifampin combination]. / Linezolid + rifampisin kombinasyonu ile tedavi edilen metisiline dirençli Staphylococcus aureus'un neden oldugu beyin apsesi olgusu.

Methicillin-resistant Staphylococcus aureus (MRSA) is a rare cause of cerebral abscesses, however it is a relatively more common etiologic agent in post-neurosurgical abscesses and the main antibacterial therapy option is vancomycin. In this report, a case of brain abscess due to MRSA which did not respond neither to moxifloxacin + vancomycin nor vancomycin + rifampin combination therapies, and merely treated by linezolid + rifampin combination, has been presented. Fifty-one years old female patient who was operated 40 days ago for subarachnoid bleeding and aneurysm in middle cerebral artery bifurcation, was hospitalized due to purulent leakage from the operation area. She did not have fever and her physical examination, including the neurologic system, was normal. Computerized tomography revealed an approximately 1 cm lesion compatible with subdural empyema and cerebral abscess in the right frontoparietal area in supratentorial sections. The patient was operated for wound revision and moxifloxacin was initiated. Since the operation materials revealed MRSA growth, vancomycin (4 x 500 mg, IV) was added to the treatment. The isolate was identified by conventional methods, and antibiotic susceptibility test performed by disk diffusion method showed that it was susceptible to levofloxacin, linezolid, rifampin, vancomycin and teicoplanin. Since no clinical response was obtained in two weeks, moxifloxacin was switched to rifampin (300 mg 1 x 2). On the 10th day of vancomycin + rifampin therapy, radiological findings showed development of cerebritis and therefore vancomycin was changed with linezolid (2 x 600 mg, IV). The control CT of the patient revealed regression of the brain lesion and linezolid + rifampin treatment continued for six weeks. The patient did not develop any hematological, liver or renal toxicity during the therapy and the radiological findings regressed. No relapse were detected in the one year follow-up period. This case suggested that linezolid might be a treatment alternative in the therapy of vancomycin-refractory MRSA brain abscess.

Meningitis due to Providencia stuartii.

In this report, we present a case of postneurosurgical meningitis due to Providencia stuartii, which was treated successfully with meropenem therapy lasting 21 days.

Protective effects of tadalafil on experimental spinal cord injury in rats.

Tadalafil is a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5). Nitric oxide (NO) functions as a retrograde neurotransmitter in the spinal cord, and postsynaptic structures respond to NO by producing cGMP. The concentrations of cGMP in the spinal cord are controlled by the actions of PDE. The aim of the study was to evaluate and compare the effects of the use of both methylprednisolone and tadalafil on serum and tissue concentrations of NO, malondialdehyde (MDA) levels, superoxide dismutase (SOD) activity, and tissue glutathione peroxidase (GSH-Px) activity in rats with spinal cord injury (SCI). SCI was induced in Wistar albino rats by dropping a 10 g rod from a 5.0 cm height at T8-10. The 28 rats were randomly divided into four equal groups: tadalafil, methylprednisolone, non-treatment and sham groups. Rats were neurologically tested at 24 hours after trauma. At the end of the experiment, blood samples were collected and spinal cord tissue samples were harvested for biochemical evaluation. The tissue level of NO was increased in the tadalafil group compared with the non-treatment and methylprednisolone groups (p<0.05). The tissue levels of SOD and GSH-Px did not differ between the groups. Serum levels of NO were higher in the tadalafil group than in the non-treatment group (p<0.05). The increase in serum SOD levels was greater in the tadalafil group than the methylprednisolone group. Serum MDA levels in the tadalafil and methylprednisolone groups tended to be lower than in the non-treatment group (p>0.05). Tissue MDA levels in the tadalafil and methylprednisolone groups tended to be lower than in the non-treatment group and sham groups (p>0.05). Although there was no difference in neurological outcome scores between the tadalafil, methylprednisolone and non-treatment groups (p>0.05), the animals in the tadalafil and methylprednisolone groups tended to have better scores than the non-treatment group. Thus, tadalafil appears to be beneficial in reducing the effects of injury to the spinal cord by increasing tissue levels of NO and serum activity of SOD.

Reliability of diffusion weighted MR imaging in differentiating degenerative and infectious end plate changes.

BACKGROUND: The aim of the study was to investigate the value of diffusion weighted MR imaging in the diagnosis of Modic type 1 change, which may be confused with the acute infectious spondylodiscitis on conventional MR imaging. PATIENTS AND METHODS: Twenty-seven patients with erosive intervertebral osteochondrosis, Modic type 1 and 18 patients with spondylodiscitis were included in this retrospective study. All images were acquired using on 1.5 Tesla MR units. Lumbar spinal MR imaging of 45 patients were retrieved from a digital database of a radiology record system and evaluated by one experienced radiologist. Patients with Modic type 1 change had CT slices obtained from the diseased disc space and the affected vertebrae. RESULTS: Bone marrow adjacent to the vertebral end plate in both Modic type 1 change and acute spondylodiscitis were hypointense on T1-weighted images. On T2-weighted images corresponding levels of vertebral end-plates showed hyperintense signal intensity in both group. All the patients with spondylodiscitis and Modic type 1 change were hyperintense and hypointense on diffusion-weighted MR images, respectively. CONCLUSIONS: Our findings suggest that diffusion weighted MR imaging is an useful method in differentiating Modic type 1 changes from acute spondylodiscitis, both of which may mimic each other, either on clinical or conventional MRI findings.

Perfusion and diffusion MR imaging in enhancing malignant cerebral tumors.

OBJECTIVE: Common contrast-enhancing malignant tumors of the brain are glioblastoma multiforme (GBMs), anaplastic astrocytomas (AAs), metastases, and lymphomas, all of which have sometimes similar conventional MRI findings. Our aim was to evaluate the role of perfusion MR imaging (PWI) and diffusion-weighted imaging (DWI) in the differentiation of these contrast-enhancing malignant cerebral tumors. MATERIALS AND METHODS: Forty-eight patients with contrast-enhancing and histologically proven brain tumors, 14 AAs, 17 GBMs, nine metastases, and eight lymphomas, were included in the study. All patients have undergone routine MR examination where DWI and PWI were performed in the same session. DWI was performed with b values of 0, 500, and 1000 mm(2)/s. Minimum ADC values (ADC(min)) of each tumor was later calculated from ADC map images. PWI was applied using dynamic susceptibility contrast technique and maximum relative cerebral blood volume (rCBV(max)) was calculated from each tumor, given in ratio with contralateral normal white matter. Comparisons of ADC(min) and rCBV(max) values with the histological types of the enhancing tumors were made with a one-way analysis of variance and Bonferroni test. A P value less than 0.05 indicated a statistically significant difference. RESULTS: The ADC(min) values (mean+/-S.D.) in GBMs, AAs, lymphomas, and metastases were 0.79+/-0.21 (x10(-3)mm(2)/s), 0.75+/-0.21 (x10(-3)mm(2)/s), 0.51+/-0.09 (x10(-3)mm(2)/s), and 0.68+/-0.11 (x10(-3)mm(2)/s), respectively. The difference in ADC(min) values were statistically significant between lymphomas and GBMs (P<0.05). It was also statistically significant between lymphomas and AAs (P<0.03). However, there were no differences between lymphomas and metastasis, and between GBMs, AAs, and metastasis. The rCBV(max) ratio (mean+/-S.D.) in GBMs were 6.33+/-2.03, whereas it was 3.66+/-1.79 in AAs, 2.33+/-0.68 in lymphomas, and 4.45+/-1.87 in metastases. These values were statistically different between GBMs and AAs (P<0.001), GBMs and lymphoma (P<0.0001). Although there seemed to be difference between GBMs and metastases, it was not statistically significant (P<0.083). CONCLUSION: Combination of DWI and PWI, with ADC(min) and rCBV(max) calculations, may aid routine MR imaging in the differentiation of common cerebral contrast-enhancing malignant tumors.

Hemodynamic and electrolyte changes in patients undergoing neuroendoscopic procedures.

OBJECTS: Intraoperative hemodynamic alterations and postoperative electrolyte disturbances related to endoscopic third ventriculostomy (E3V) have been reported. We aimed to evaluate prospectively those changes in patients undergoing neuroendoscopic procedures. METHODS: This study was carried out in 24 patients who underwent neuroendoscopic intervention. Sevoflurane was used for the induction and maintenance of anesthesia. Heart rate (HR), mean arterial pressure (MAP), peripheral oxygen saturation, end-tidal CO2, and body temperature values were recorded according to the stages of the operation. Blood gas and blood chemistry analyses were performed before and after endoscopic procedure and were repeated on the third postoperative day. CONCLUSIONS: There were no significant differences in intraoperative HR and MAP. Bradycardia occurred only in 1 of the 24 patients during the dilatation. In conclusion, we suggest the use of 0.9% NaCl for intravenous fluid replacement and a warm lactated ringer solution for ventricular irrigation during E3V to prevent intraoperative hemodynamic changes and postoperative electrolyte disturbances.

Vancomycin versus teicoplanin in the therapy of experimental methicillin-resistant Staphylococcus aureus (MRSA) meningitis.

The aim of this study was to compare the antibacterial activity of teicoplanin and vancomycin in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) meningitis using a rabbit meningitis model. The MRSA strain ATCC 43300 was used to infect the rabbits. The vancomycin group received 20 mg/kg vancomycin every 12h (q12h), the teicoplanin group received 6 mg/kg teicoplanin q12h and the control group did not receive any treatment. Drug levels were measured using a bioassay technique. Bacterial counts in the treatment groups were significantly lower (P<0.05) than those of the control group at 12 h and 24 h after treatment. When the treatment groups were compared, the bacterial counts after 12 h or 24 h of treatment were similar (P>0.05). These data suggest that the antibacterial activity of vancomycin and teicoplanin are similar in experimental MRSA meningitis of rabbits.

Minimum apparent diffusion coefficients in the evaluation of brain tumors.

OBJECTIVE: To determine whether diffusion-weighted imaging by using minimum apparent diffusion coefficient (ADC(min)) values could differentiate various brain tumors including gliomas, metastases, and lymphomas. MATERIALS AND METHODS: We examined 65 patients with histologically or clinically diagnosed brain tumors (12 low-grade gliomas, 31 high-grade gliomas, 14 metastatic tumors, and 8 lymphomas) using a 1.5 T MR unit. On diffusion-weighted imaging, the ADC(min) values were measured within the tumors and mean values were evaluated regarding statistical differences between groups. RESULTS: The ADC(min) values of low-grade gliomas (1.09+/-0.20 x 10(-3)mm(2)/s) were significantly higher (p<.001) than those of other tumors. There were no statistical significant differences between glioblastomas (0.70+/-0.16 mm(2)/s), anaplastic astrocytomas (0.77+/-0.21 mm(2)/s), metastases (0.78+/-0.21 mm(2)/s), and lymphomas. But, lymphomas had lower mean ADC(min) values (0.54+/-0.10mm(2)/s) than high-grade gliomas and metastases. CONCLUSION: The ADC measurements may help to differentiate low-grade gliomas from high-grade gliomas, metastases, and lymphomas. Although there is no statistical difference, lymphomas seem to have marked restriction in diffusion coefficients.

Rifampicin+ceftriaxone versus vancomycin+ceftriaxone in the treatment of penicillin- and cephalosporin-resistant pneumococcal meningitis in an experimental rabbit model.

This study was planned to compare the efficacy of ceftriaxone+vancomycin with ceftriaxone+rifampicin in a rabbit model of penicillin and cephalosporin-resistant Streptococcus pneumoniae meningitis. Meningitis was induced by intracisternal inoculation of S. pneumoniae. After 18 h of incubation, Group 1 was given saline solution (control group), whilst Groups 2 and 3 were given ceftriaxone+vancomycin and ceftriaxone+rifampicin, respectively. Cerebrospinal fluid bacterial concentrations were measured at 0, 2, 12, 14 and 24 h after therapy was initiated. In the control group, bacterial growth was present at all time points, whereas no growth was observed in either the ceftriaxone+vancomycin group or the ceftriaxone+rifampicin group after 2 h of therapy. Ceftriaxone+rifampicin was found to be as effective as ceftriaxone+vancomycin in the treatment of penicillin-resistant S. pneumoniae meningitis in experimental rabbit model.