Trophic transfer of nano-TiO2 in a paddy microcosm: A comparison of single-dose versus sequential multi-dose exposures

In the present study, replicated paddy microcosm systems were used to investigate the environmental fate and trophic transfer of titanium nanoparticles (NPs) over a period of 14 days. Most TiO2 NPs immediately settled down in the sediment, and high accumulations of nano TiO2 in the sandy loam sediment and biofilm were observed. The test organisms (quillworts, water dropworts, duckweeds, biofilms, river snails, and Chinese muddy loaches) and environmental media (freshwater, sandy loam sediment) were exposed to sequential low doses (2 mg/L at 1 h, 4 days, and 9 days) or a single high-dose (6 mg/L) of TiO2 NPs. The bioconcentration factors (BCFs) of nano-TiO2 in biofilms, quillworts, duckweeds, and Chinese muddy loaches were higher in the sequential multi-dose group than in the single-dose group. Chinese muddy loaches showed higher bioaccumulation factors (BAFs) over their prey than river snails. The difference in the carbon isotope ratios between Chinese muddy loaches and river snails was less than 2‰, and an approximately 4‰ difference in the stable nitrogen isotope ratio was observed in the two aquatic predators from their major prey (e.g., biofilms or particulate organic matter). The trophic levels between biofilms and river snails and between biofilms and Chinese muddy loaches were 2.8 and 2.4 levels, respectively. These results indicate that these two predators consumed biofilm and other alternative preys at a higher level than biofilm. Although the trophic transfer rates of TiO2 are generally low, relatively higher biomagnification factors (BMFs) were found in Chinese muddy loaches (0.04-0.05) than in river snails (0.01-0.02). These results suggest that TiO2 NPs show greater movement in the sediment than in the water and that TiO2 NPs can be retained through aquatic food chains more after a sequential low-dose exposure than after a single high-dose exposure.

Transarterial embolisation of renal arteriovenous malformation: safety and efficacy in 24 patients with follow-up

AIM

To evaluate the efficacy and safety of renal artery embolisation (RAE) for renal arteriovenous malformation (AVM) as well as its outcomes.

MATERIALS AND METHODS

The technical and clinical success rates, radiological and laboratory findings, and complications of RAE for 31 renal AVMs in 24 patients (M:F=9:15, mean age 46 years) at two separate medical institutions were retrospectively evaluated. Technical success was defined as complete occlusion of feeding arteries with no residual nidus seen on post-treatment angiography. Clinical failure was defined as recurrence of haematuria, presence of AVM on follow-up ultrasound or computed tomography, repeated RAE or surgery for the control of haematuria. Overall clinical success was defined as resolution haematuria or disappearance of AVM on follow-up imaging after single or multiple sessions of RAE.

RESULTS

Types of renal AVM were AVM, arterio-venous fistula (AVF) with intranidal aneurysm, and acquired AVF in 19, 1, and 4 patients, respectively. 18 patients (75%) underwent a single session of RAE, while 6 patients (25%) had two or more sessions of RAE. The level of embolisation was feeder, segmental artery, and main renal artery in 28 (90%), 2 (6%), and 1 (4%) procedures, respectively. Coil, n-butyl 2-cyanoacrylate, and polyvinyl alcohol were the most frequently chosen embolic materials and were used in 19, 14, and 8 procedures, respectively. The clinical success rate after initial RAE was 67% (16/24). Overall clinical success rate, including multisession RAE, was 88% (21/24). The technical success rate of 31 procedures was 65% (20/31). Among 11 technical failures in 10 patients, 4 achieved clinical success without additional RAE, 3 underwent second session RAE to achieve clinical success, and 3 patients underwent nephrectomy due to recurrence.

CONCLUSION

RAE is a safe and effective treatment for renal AVM. Technical failure of RAE does not always lead to clinical failure and multiple embolisation sessions may be effective for recurrent renal AVM.

Closed reduction of displaced or dislocated mandibular condyle fractures in children using threaded Kirschner wire and external rubber traction

Most surgeons agree that closed treatment provides the best results for condylar fractures in children. Nevertheless, treatment of the paediatric mandibular condyle fracture that is severely displaced or dislocated is controversial. The purpose of this study was to investigate the long-term clinical and radiological outcomes following the treatment of displaced or dislocated condylar fractures in children using threaded Kirschner wire and external rubber traction. This procedure can strengthen the advantage of closed reduction and make up for the shortcomings of open reduction. From March 1, 2005 to December 25, 2011, 11 children aged between 4 and 12 years with displaced or dislocated mandibular condyle fractures were treated using threaded Kirschner wire and external rubber traction under portable C-arm fluoroscopy. All patients had unilateral displaced or dislocated condylar fractures. The follow-up period ranged from 24 to 42 months (mean 29.3 months). Normal occlusion and pain-free function of the temporomandibular joint, without deviation or limitation of jaw opening, was achieved in all patients. This closed reduction technique in displaced or dislocated condylar fractures in children offers a reliable solution in preventing the unfavourable sequelae of closed treatment and the open technique, such as altered morphology, functional disturbances, and facial nerve damage.

Fibroblast growth factor 21 improves insulin resistance and ameliorates renal injury in db/db mice

Despite the emerging importance of fibroblast growth factor 21 (FGF21) as a metabolic hormone regulating energy balance, its direct effects on renal function remain unexplored. FGF21 was injected ip daily for 12 weeks into db/db mice. Compared with control vehicle injection, FGF21 treatment significantly improved lipid profiles and insulin resistance and resulted in significantly higher serum adiponectin levels. In contrast, serum insulin and 8-isoprostane levels were significantly decreased. Interestingly, FGF21 and its receptor components in the kidneys were found to be significantly up-regulated in db/db mice, which suggests an FGF21-resistant state. FGF21 treatment significantly down-regulated FGF21 receptor components and activated ERK phosphorylation. FGF21 administration also markedly decreased urinary albumin excretion and mesangial expansion and suppressed profibrotic molecule synthesis. Furthermore, FGF21 improved renal lipid metabolism and oxidative stress injury. In cultured renal cells, FGF21 was mainly expressed in mesangial cells, and knockdown of FGF21 expression by stealth small interfering RNA further aggravated high-glucose-induced profibrotic cytokine synthesis in mesangial cells. Our results suggest that FGF21 improves insulin resistance and protects against renal injury through both improvement of systemic metabolic alterations and antifibrotic effects in type 2 diabetic nephropathy. Targeting FGF21 could therefore provide a potential candidate approach for a therapeutic strategy in type 2 diabetic nephropathy.

Renal protective effects of toll-like receptor 4 signaling blockade in type 2 diabetic mice

Chronic inflammation caused by high glucose and high free fatty acid (FFA) concentrations is a major contributor to the pathogenesis of type 2 diabetes. Recent evidence suggests that activation of Toll-like receptor (TLR) signaling induces peripheral insulin resistance and mediates central insulin and leptin resistance. In this study, we investigated the renal effects of TLR4 signaling blockade in type 2 diabetic mice. Eight-week-old db/db mice were treated for 12 weeks with (S,R)-3-phenyl-4,5-dihydro-5-isoxasole acetic acid (GIT27), which targets macrophages through the inhibition of TLR4- and TLR2/6-mediated signaling pathways. Although GIT27 treatment improved glycemic control and insulin tolerance, which is associated with a lower lipid profile, it did not impact body weight or food consumption. GIT27 treatment also markedly decreased urinary albumin excretion, decreased proinflammatory cytokine synthesis, improved tissue lipid metabolism, induced oxidative stress, and improved glomerulosclerosis compared with the control db/db group. In cultured podocytes and adipocytes, high glucose levels with FFA stimulation increased TLR4 expression and proinflammatory cytokine synthesis, but the effects were abolished by GIT27 treatment. In addition, knockdown of TLR4 expression by stealth small interfering RNA abolished FFA-induced proinflammatory cytokine synthesis in cultured podocytes. In conclusion, our results suggest that GIT27 treatment improves insulin resistance and protects against the renal injury that occurs in type 2 diabetic nephropathy through both metabolic and antiglomerulosclerotic mechanisms. These results suggest that TLR pathway inhibition might play a direct protective role in diabetic kidney disease.

Blockade of cannabinoid receptor 1 improves insulin resistance, lipid metabolism, and diabetic nephropathy in db/db mice

The endocannabinoid system is important in the pathogenesis of obesity-related metabolic disorders. However, the effect of inhibiting the endocannabinoid system in type 2 diabetic nephropathy is unclear. Therefore, we examined the effect of the cannabinoid (CB)1 receptor antagonist, SR141716, on insulin resistance and diabetic nephropathy in db/db mice. Six-week-old db/db mice were treated with the CB1-specific antagonist SR141716 (10 mg/kg · d) for 3 months. Treatment with SR141716 significantly improved insulin resistance and lipid abnormalities. Concomitantly, CB1 antagonism improved cardiac functional and morphological abnormality, hepatic steatosis, and phenotypic changes of adipocytes into small differentiated forms, associated with increased adiponectin expression and decreased lipid hydroperoxide levels. CB1 receptor was overexpressed in diabetic kidneys, especially in podocytes. Treatment with the SR141716 markedly decreased urinary albumin excretion and mesangial expansion and suppressed profibrotic and proinflammatory cytokine synthesis. Furthermore, SR141716 improved renal lipid metabolism and decreased urinary 8-isoprostane levels, renal lipid hydroperoxide content, and renal lipid content. In cultured podocytes, high-glucose stimulation increased CB1 receptor expression, and SR141716 treatment abolished high-glucose-induced up-regulation of collagen and plasminogen activator inhibitor-1 synthesis. Additionally, knockdown of CB1 receptor expression by stealth small interfering RNA abolished high-glucose-induced sterol-regulatory element-binding protein-1 expression in podocytes. These findings suggest that CB1 blockade improves insulin resistance and protect against renal injury through both metabolic and antifibrotic effects in type 2 diabetic nephropathy. Targeting CB1 blockade could therefore provide a new therapeutic target to prevent type 2 diabetic nephropathy.

Differential diagnosis of idiopathic normal pressure hydrocephalus from other dementias using diffusion tensor imaging

BACKGROUND AND PURPOSE

Because DTI can provide good markers of white matter pathology, it could be useful in differentiating white matter changes of INPH from those of other dementias. The aim of this study was, by using DTI, to compare the characteristic white matter changes in INPH with those in AD, subcortical vascular dementia, and healthy control subjects.

MATERIALS AND METHODS

Sixteen patients with presurgical INPH, 10 with AD, 10 with subcortical vascular dementia, and 20 healthy control subjects underwent DTI. All patients with INPH showed clinical improvement after shunt surgery, and 9 of them also underwent postshunting DTI. Regions of interest were selected at the periventricular white matter, the anterior limb of the internal capsule, the posterior limb of the internal capsule, the genu and the splenium of the corpus callosum, the superior longitudinal fasciculus, and the inferior longitudinal fasciculus. FA and MD were obtained from each region of interest and were compared among the groups.

RESULTS

Presurgical INPH showed significantly higher FA than all the other groups in the posterior limb of the internal capsule, which was decreased after shunt surgery. Presurgical MD of the INPH group was higher than that in the AD and healthy control groups but lower than that in the subcortical vascular dementia group in the anterior periventricular white matter, the anterior limb of the internal capsule, and the superior longitudinal fasciculus. In differentiating INPH, the sensitivity and specificity of FA in the posterior limb of the internal capsule was 87.5% and 95.0%, respectively.

CONCLUSIONS

Patients with shunt-responsive INPH showed higher FA in the posterior limb of the internal capsule compared with healthy controls and those in other groups of dementia that was reversible with shunt surgery. With this parameter, shunt-responsive INPH could be distinguished from AD, subcortical vascular dementia, and healthy conditions with high diagnostic accuracy.

Time-resolved MR angiography for detecting and grading ovarian venous reflux: comparison with conventional venography

OBJECTIVE

The purpose of this study was to compare the diagnostic accuracy of time-resolved MR angiography (TR-MRA) with that of conventional venography for the detection and grading of ovarian venous reflux, which aid in the diagnosis of pelvic venous congestion.

METHODS

We performed a retrospective analysis of 19 consecutive patients who underwent TR-MRA and conventional venography. The images were analysed by two radiologists in a randomised "blinded" manner. With the use of conventional venography as a gold standard, the images were reviewed to determine if differences in the detection and grading of ovarian venous reflux were seen between TR-MRA and conventional venography; the sensitivity, specificity and accuracy of TR-MRA compared with that of conventional venography were evaluated. The McNemar test was performed to determine the significance of any differences. Interobserver agreement was analysed using generalised κ statistics.

RESULTS

There was no significant difference between TR-MRA and conventional venography for grading ovarian venous reflux (p>0.05). The sensitivity, specificity and diagnostic accuracy of TR-MRA were found to be 66.7%, 100% and 78.9%, and 75%, 100% and 84.2%, respectively, for the two observers. The weighted κ-values indicated excellent agreement between the two observers for grading ovarian venous reflux on TR-MRA (κ = 0.894).

CONCLUSION

TR-MRA is an accurate method for accessing pelvic venous congestion.

Abstract P6-13-05: Differences of Clinical Manifestations and Therapeutic Outcomes in Leptomeningeal Metastases (LM) According to Breast Cancer Subtypes

Backgrounds: Breast cancer is the solid tumor most commonly associated with leptomeningeal metastases (LM). Therapeutic modalities include intrathecal and systemic chemotherapy, radiotherapy and other palliative modality including placement of a ventricular reservoir. The aim of this study is to characterize clinical feature and outcomes of LM according to breast cancer subtypes in conjunction with whole CNS metastases.

Methods: A retrospective study was performed on breast cancer patients with LM who received palliative management at Samsung Medical Center between 1994 and 2008. Among 281 metastatic breast cancer patients, 71 breast cancer patients with LM were identified. They were divided into three biological subgroups. The propensity of biological subtypes for LM, clinical manifestation including recursive partitioning analysis of Radiation Therapy Oncology Group (RPA RTOG) prognostic class, and therapeutic outcomes were assessed.

Results: The median age was 48 (range 26-70) years. The rates of the patients with triple negative breast cancer (TNBC), human epidermal growth factor receptors 2 (HER2)-positive and hormone receptor (HR)- positive subtype breast cancer were 26 (44%), 15 (25%) and 18 (31%), respectively. Sixty-four patients (90%) had metastatic disease at sites other than LM. TNBC were more common in RPA RTOG prognostic class III than those in HER2 and HR-positive subtypes (61% vs 39% vs 0%, P<0.0001). CNS including LM was the first site of distant metastasis in 65% of the TNBC patients. Treatment includes intrathecal chemotherapy (IT), whole brain radiotherapy (WBRT), and systemic chemotherapy. The median survival duration from the diagnosis of LM to death (OS-LM) was 4.5 months (range 0.2-26.4 months). Main causes of death were deterioration of neurologic sequelae associated with LM (55%), systemic disease progression (27%), and et cetera (18%). Death rates related with LM at each subtype were 64% for TNBC, 36% for HER2-positive, and 0% for HR-positive patients (p=0.060). In the univariate analysis, RPA RTOG classification (p=0.003), systemic disease control at LM (p=0.041), cytologic negative conversion to IT (p=0.001), systemic chemotherapy after LM diagnosis (p=0.002), and combined modality for LM treatment (p=0.005) were singled out as having prognostic value for OS-LM. Cox-regression multivariate analysis showed that RPA class (HR (Hazard Ratio) 1.8, p=0.022), cytologic negative conversion to IT (HR 0.4, p=0.043), and systemic chemotherapy (HR 0.24, p=0.004) are identified as independent prognostic factors.

Conclusion: TNBC and HER2-positive breast cancer appeared to have special predilection for LM as well as brain parenchymal metastases. High RPA class of TNBC may reflect more aggressive tumor biology in this sanctuary area. OS-LM depended on RPA class, cytologic negative conversion, and the use of systemic chemotherapy. The role of systemic chemotherapy and active local treatment modalities according to subtypes should be defined to improve dismal prognosis.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-13-05.

Acute appendicitis: relationships between CT-determined severities and serum white blood cell counts and C-reactive protein levels

OBJECTIVES

The aim of this study was to evaluate the relationships between the severity of appendicitis as depicted on CT and blood inflammatory markers of serum white blood cell (WBC) count and C-reactive protein (CRP).

METHODS

CT images in 128 patients (109 surgically proven and 19 with clinically excluded appendicitis) were retrospectively reviewed. Two radiologists by consensus evaluated and scored (using a 0, 1 or 2 point scale) severities based on CT-determined appendiceal diameters, appendiceal wall changes, caecal changes, periappendiceal inflammatory stranding and phlegmon or abscess formation. We investigated whether CT findings were significantly related to elevated WBC counts or CRP levels and performed the correlations of WBC counts and CRP levels with CT severity scores. Patients were also subjectively classified using four grades from normal (Grade I) to perforated appendicitis (Grade IV) on the basis of CT findings to evaluate differences in WBC counts and CRP levels between grades.

RESULTS

Only appendiceal wall changes and the phlegmon or abscess formation were related to elevated WBC counts and CRP levels, respectively (p<0.05). CT severity scores were found to be more strongly correlated with CRP levels (r = 0.669) than with WBC counts (r = 0.222). On the basis of CT grades, the WBC counts in Grade I were significantly lower than in other grades (p<0.001), whereas CRP levels in Grade IV were significantly higher than in other grades (p<0.001).

CONCLUSION

CRP levels were found to correlate with CT-determined acute appendicitis severity and could be a useful predictor for perforated appendicitis, whereas WBC counts might be useful to detect early acute appendicitis.

The detection and discrimination of malignant and benign focal hepatic lesions: T2 weighted vs diffusion-weighted MRI

OBJECTIVE

The purpose of this study was to evaluate the use of diffusion-weighted imaging (DWI) for the detection and characterisation of focal hepatic lesions compared with the use of T(2) weighted imaging.

METHOD

45 patients with 97 hepatic lesions (51 malignant lesions and 46 benign lesions) were included in this retrospective study. Malignant hepatic lesions included 12 hepatocellular carcinomas, 26 metastases and 13 intrahepatic cholangiocarcinomas. Benign hepatic lesions included 19 haemangiomas and 27 cysts. The MRI protocol for the upper abdomen included T(2) weighted images, in- and opposed-phase T(1) weighted images and dynamic T(1) weighted images. Breath-hold fat-suppressed single-shot echo planar DWI was performed with the following parameters: 1338/66; b factors, 0, 50 and 800 s mm(-2). Two independent observers reviewed the T(2) weighted images and the DWI to detect and to characterise the hepatic lesions.

RESULTS

For detection of malignant hepatic lesions, the use of DWI showed a significantly higher detection rate than the use of T(2) weighted images (p<0.05). However, there was no significant difference between the use of DWI and T(2) weighted images for benign hepatic lesions. For the differentiation between malignant and benign hepatic lesions, there was no significant difference in sensitivity, specificity and accuracy between the use of T(2) weighted images and the use of DWI.

CONCLUSION

The use of DWI was better for the detection of malignant hepatic lesions than the use of T(2) weighted images. However, for detection of benign hepatic lesions and characterisation of hepatic lesions, the use of DWI was equivalent to the use of T(2) weighted images.

Malignant esophageal-tracheobronchial strictures: parallel placement of covered retrievable expandable nitinol stents

PURPOSE

To assess the safety and clinical effectiveness of the parallel placement of covered retrievable expandable metallic stents in the palliative treatment of malignant esophageal and tracheobronchial strictures.

MATERIAL AND METHODS

Under fluoroscopic guidance, parallel stents were placed in 12 symptomatic patients with both malignant esophageal and tracheobronchial strictures. Seven of these 12 patients also had an esophagorespiratory fistula (ERF) and one patient had an esophagocutaneous fistula. Technical success, clinical improvement, complications, and survival rates were evaluated.

RESULTS

A total of 28 esophageal and airway stents were successfully placed. The grade of dysphagia and dyspnea score significantly decreased after stent placement (P=0.002 and 0.003, respectively). ERF and esophagocutaneous fistula were sealed off in all eight patients after esophageal stent placement; however, the esophagocutaneous fistula reopened 1 month later. Complications included stent migration or expectoration (n=3), tracheal compression by the esophageal stent (n=3), new fistula development due to covering membrane degradation of the esophageal stent (n=1), and symptomatic sputum retention (n=1). Stent removal was easily performed for two stents; one migrated stent and the other with covering membrane degradation. All 12 patients died within the mean survival period of 72.50 days (range 7-375 days).

CONCLUSION

Parallel placement of covered retrievable expandable metallic stents is safe and effective for the palliative treatment of malignant esophageal and tracheobronchial strictures.

Quantitative analysis of errors in fractionated stereotactic radiotherapy

Fractionated stereotactic radiotherapy (FSRT) offers a technique to minimize the absorbed dose to normal tissues; therefore, quality assurance is essential for these procedures. In this study, quality assurance for FSRT of 58 cases, between August 1995 and August 1997 are described, and the errors for each step and overall accuracy were estimated. Some of the important items for FSRT procedures are: accuracy in CT localization, transferred image distortion, laser alignment, isocentric accuracy of linear accelerator, head frame movement, portal verification, and various human errors. A geometric phantom, that has known coordinates was used to estimate the accuracy of CT localization. A treatment planning computer was used for checking the transferred image distortion. The mechanical isocenter standard (MIS), rectilinear phantom pointer: (RLPP), and laser target localizer frame (LTLF) were used for laser alignment and target coordinates setting. Head-frame stability check was performed by a depth confirmation helmet (DCH). A film test was done to check isocentric accuracy and portal verification. All measured data for the 58 patients were recorded and analyzed for each item. 4-MV x-rays from a linear accelerator, were used for FSRT, along with homemade circular cones with diameters from 20 to 70 mm (interval: 5 mm). The accuracy in CT localization was 1.2+/-0.5 mm. The isocentric accuracy of the linear accelerator, including laser alignment, was 0.5+/-0.2 mm. The reproducibility of the head frame was 1.1+/-0.6 mm. The overall accuracy was 1.7+/-0.7 mm, excluding human errors.

Expression of interleukin-1 beta in lipopolysaccharide stimulated monocytes derived from patients with aneurysmal subarachnoid hemorrhage is correlated with cerebral vasospasm

Cerebral arterial vasospasm is a frequent complication after aneurysmal subarachnoid hemorrhage (SAH). Immunological activation may affect the development of vasospasm. This study measured the cytokines released from lipopolysaccharide-stimulated monocytes of SAH patients. We measured cerebral artery diameters before and after surgery for SAH. The activation index of interleukin-1 beta (IL-1 beta), but not tumor necrosis factor-alpha (TNF-alpha), was higher in patients with symptomatic vasospasm (5.6+/-1.7; n=11) than in patients without (1.8+/-0.4; n=11) (P=0.039). Furthermore, the IL-1 beta activation index was correlated with the degree of the postoperative angiographic vasospasm (correlation coefficient=-0.66, P=0.007). Individual variation in systemic immune activation, measured by monocyte-derived IL-1 beta expression levels after stimulation, may be associated with the development of vasospasm after aneurysmal SAH.

Biosynthetic pathway of cephabacins in Lysobacter lactamgenus: molecular and biochemical characterization of the upstream region of the gene clusters for engineering of novel antibiotics

The cephabacins, one of the beta-lactam antibiotics, are produced by Lysobacter lactamgenus. The previous studies the cephabacin biosynthesis were limited to a gene cluster that encodes the gene products responsible for the biosynthesis of the cephem nucleus. The long-term goal of this research is to elucidate the metabolic diversity and biosynthetic pathway of cephabacins and to design and/or discover new pharmacologically active compounds by engineering the cephabacin biosynthetic pathway in L. lactamgenus. In this study, we have cloned and sequenced a 24-kb fragment of a DNA locus upstream of the previously reported but incomplete putative ORF9 of L. lactamgenus. This contains three putative ORFs (the complete ORF9, ORF10, and ORF11) transcribed in the same direction and one putative ORF (ORF12) in the opposite direction. The isolated DNA locus extends the previously cloned part of the DNA locus containing the genes responsible for biosynthesis of the cephem nucleus up to 45 kb. The 42-kb fragment of the 45-kb gene cluster is located between a potential TATA box just upstream of the ORF11 and a termination loop just downstream of the previously reported bla gene. The complete ORF9 contains three nonribosomal peptide synthetase (NRPS) modules and one polyketide synthase (PKS) module and the ORF11 contains one NRPS module. The complete ORF9 also contains a putative thioesterase domain at the C-terminal end. We predicted the amino acid specificity of the four NRPSs by generating specificity binding pockets and expressed one of the NRPSs to confirm the amino acid specificity. The adenylation domain of the NRPS1, which is the last module of the NRPSs, showed significant amino acid specificity for L-arginine. These findings are in perfect agreement with the composition that was expected for the structure of cephabacins which contain an acetate residue, an L-arginine, and one to three L-alanines at the C-3' position of the cephem nucleus of cephabacins. The ORF10, encoding a putative ABC transporter which might be involved in conferring resistance against cephabacins, was identified between the complete ORF9 and the ORF11. Therefore, the complete ORF9, ORF10, ORF11 reported here and the other genes previously reported constitute an operon for the biosynthesis of cephabacins in L. lactamgenus. Based on our results, the biosynthetic pathways of acetate and elongated peptide moieties and a mechanism by which cephabacins are assembled by connecting the peptide moiety synthesized by the gene products of the complete ORF9 and the ORF11 to the C-3' position of the cephem nucleus synthesized by the gene products of pcbAB, pcbC, cefE, cefF, and cefD have been elucidated.

Increased burst firing in substantia nigra pars reticulata neurons and enhanced response to selective D2 agonist in hemiparkinsonian rats after repeated administration of apomorphine

Intermittent administrations of dopaminergic agents in hemiparkinsonian rat enhances the behavioral response to subsequent administration of the drugs. This phenomenon is known as "priming" and thought as comparable to drug-induced dyskinesia in patients with Parkinson's disease. We investigated the behavioral and electrophysiological changes in 6-hydroxydopamine (6-OHDA)-lesioned hemiparkinsonian rats after repeated administrations of apomorphine. Administration of apomorphine (0.32 mg/kg, intraperitoneal, i.p.) twice daily for 6 days enhanced the rotation induced by apomorphine from 341 turns/hour at the beginning to 755 turns/hr at the end. At the same time, the response to selective D2 agonist quinpirole (0.26 mg/kg, i.p.) was also enhanced from 203 to 555 turns/hr. Extracellular single unit recording revealed no significant difference in the basal firing rates of substantia nigra pars reticulata (SNr) neurons between the ipsilateral and contralateral side of the 6-OHDA lesion regardless of the repeated administrations of apomorphine. In SNr of the lesion side, the units with burst firing pattern were found more frequently after repeated administrations of apomorphine and the suppressive effect of quinpirole on the firing rate was enhanced. These findings suggest that the increased percentage of the burst units is the important electrophysiological change in the development of enhanced response to selective D2 agonist.

Clinical significance of molecular genetic changes in sporadic invasive pituitary adenomas

Several molecular and genetic changes have been found in pituitary adenomas. We looked for correlations between these changes and the degree of invasiveness of the tumors. The invasiveness of 11 pituitary adenomas was graded by Hardy classification. We examined the retinoblastoma gene (RB1.20 on chromosome 13q) and the region around the MEN1 locus (chromosome 11q13.1-5) for loss of heterozygosity. Also examined are p53 mutations using single strain conformation polymorphism, p53 protein overexpression using immuno cytochemistry, homozygous deletions of p15 and p16 by polymerase chain reaction, and cellular proliferative activity using MIB-1 antibody. Six tumors (54.5%) had an LOH at either RB1.20 or the MEN1 locus. LOHs were found more frequently in Grade 4 and stage E tumors (72% and 67%) than in Grade 3 and stage D tumors (25% and 40%). However, no mutation or overexpression of p53 was found. No homozygous deletions of p15 or p16 were identified. The cell proliferative index ranged from 0 to 3%. LOH at 11q13 and 13q may be valuable in predicting the invasiveness of pituitary adenomas.

Allergenicity test of genetically modified soybean in Sprague Dawley rats

Allergenicity of genetically-modified (GM) soybean was evaluated in male Sprague Dawley rats. To confirm the GM soybean used in this study, the polymerase chain reaction (PCR) was performed using the chromosomal DNA of soybeans. The PCR result provided the clear discrimination of genetically-modified (GM) soybeans. To evaluate the allergenicity of GM soybean and non-GM control one, the soybean homogenate was sensitized subcutaneously 3 times a week for 3 weeks. The doses of soybean were 0, 2 and 20 mg/kg in the protein basis. A week after the last sensitization, antisera were recovered from individual animals. When the sera were injected intradermally on the clipped back of unsensitized rats with various dilutions, followed by a challenge with 20 mg/kg of soybean homogenate containing 1% Evans blue, no sign of passive cutaneous anaphylaxis reaction was detected. In addition, when the sera were treated in the cultures of peritoneal mast cells, the increase of histamine release by anti-(GM soybean) sera was not observed when compared to that by anti-(non-GM soybean) sera. The present results indicate that the GM soybean might not act as a strong allergen in male Sprague Dawley rats.

Comparison of visual field defects between primary open-angle glaucoma and chronic primary angle-closure glaucoma in the early or moderate stage of the disease

The visual field data (Humphrey C24-2) of early to moderate stage glaucoma between primary open-angle glaucoma (POAG) and chronic primary angle-closure glaucoma (PACG) patients was compared. Eleven POAG (11 eyes) and 14 chronic PACG patients (14 eyes) were matched with respect to age, sex, and disease severity. Although the mean deviation, pattern standard deviation, and short-term fluctuation were similar between the two groups, the mean corrected pattern standard deviation was higher in the POAG patients (p=0.048). When the numeric pattern deviation data (STATPAC II) was used for point-wise between-group comparisons, more depressed paracentral points were found in POAG patients. Different patterns were identified in visual field damages between the chronic PACG and POAG patients. The chronic PACG patients showed more generalized field loss than the POAG patients.

Surgical tactics and outcome of treatment in jugular foramen schwannomas

Seven patients with schwannomas of the jugular foramen were included our study in Samsung Medical Center between 1995 and 1999. Patients with neurofibromatosis were excluded. The records of the seven patients (six surgical case and one nonsurgical case) were retrospectively reviewed. There were six women and one man (mean age, 47 years) with a symptom duration ranging from 3 months to 14 years (mean, 47 months). The predominant symptoms were hearing difficulty, hemifacial spasm and hoarseness. Preoperative audiologic evaluation, computerised tomography (CT), magnetic resonance (MR) imaging, and angiography were performed in most patients. We classified tumours into four types using Kaye and Pellet classification on the basis of radiological and surgical findings. The tumours were: Type A (at cerebellopontine angle) in one; Type B (foraminal) in two; Type C (extracranial and/or foraminal) in two; and Type D (intra- and extracranial) in two cases. We used various surgical approaches such as retrosigmoid suboccipital craniectomy for Type A tumours, infratemporal fossa type A approach (ITFA) for Type C tumours, petro-occipital transsigmoid approach or modified transcochear approach for Type D tumours and ITFA with partial labyrinthectomy for Type B. In the selection of surgical approaches, we took consideration of tumour extension, tumour size, and preoperative hearing function. Facial nerve transposition was not used only in one case of ITFA because of small tumour size (1.5cm). Gross total removal was achieved in five cases, and subtotal removal in one case (Type D tumour) with a single-stage operation. Stereotactic radiosurgery was performed on residual mass in the subtotally removed case. Follow-up period ranged from 13 to 49 months (mean, 27.5 months). There was neither postoperative mortality nor recurrence on follow-up MR imaging. There were two cases of temporary facial nerve palsy and one aggravation of pre-existing low cranial palsy. Two case of sustained vocal cord palsy underwent thyroplasty, but there was no aspiration pneumonia. Persistent cerebrospinal fluid collection was improved with lumboperitoneal shunt. The surgical approaches of each case should be tailored according to their shape and the clinical manifestation. We obtain acceptable outcomes from one-stage operation.

The detection of p53 gene mutation using a microdissection technique in primary intracranial germ cell tumors

Using a microdissection technique, the contribution of the p53 mutation to tumorigenesis and prognosis in each histological subtype of the intracranial germ cell tumors (GCTs) was evaluated. Nineteen patients had primary intracranial GCTs, including 4 germinomas (GEs), 4 teratomas (TEs), 1 mixed tumor of GE and TE, and 10 mixed GCTs containing non-germinomatous malignant germ cell tumors (NG-MGCTs). After microdissection of specific subtypes, genomic DNA was screened for mutations in exons 5-8 of the p53 gene, using the dideoxyfingerprinting (ddF) followed by direct DNA sequencing. The direct sequencing revealed a total of six mutations in PCR products derived from the five cases (26%) which showed mobility shifts in ddF. Among the six mutations detected, four were missense mutations and two were silent. Missense mutations of the p53 gene tended to occur more frequently in the NG-MGCT component than in the GE or TE components (3/15 vs. 1/12 vs. 0/13). The incidence of missense mutations was not different between the survivors (3/13) and the deceased (1/6). This study suggests the possible role of the p53 gene in the tumori-genesis of NG-MGCT. However, p53 gene mutation did not correlate with the prognosis of NG-MGCT.

Induction of apoptosis by capsaicin in A172 human glioblastoma cells

Capsaicin induced apoptosis of A172 human glioblastoma cells in a time- and dose-dependent manner. Neither capsazepine, a vanilloid receptor antagonist, nor bis-(o-aminophenoxy)-ethane-N,N,N', N'-tetraacetic acid/acetoxymethyl ester (BAPTA/AM), an intracellular Ca(2+) chelator, significantly inhibited the capsaicin-induced apoptosis, although capsaicin increased intracellular Ca(2+) level. Capsaicin markedly reduced the basal generation of reactive oxygen species (ROS) and lipid peroxidation. Exogenous application of H(2)O(2) significantly prevented the cells from the apoptosis by capsaicin. Treatment with N-acetyl cysteine alone induced both reduction of the basal production of ROS and apoptosis. Taken together, these results suggest that capsaicin induced apoptosis in A172 cells and that vanilloid receptors and intracellular Ca(2+) may not be involved in the apoptotic mechanism of capsaicin. Reduction of the basal generation of ROS may play a role in the induction of apoptosis by capsaicin.

Effects of flupyrazofos on liver microsomal cytochrome P450 in the male Fischer 344 rat

1. The effects of flupyrazofos on liver microsomal cytochrome P450 were investigated in the male Fischer 344 rat. When rats were treated intraperitoneally with flupyrazofos for 3 consecutive days, the activities of ethoxyresorufin O-deethylase and testosterone 2 beta-hydroxylase were significantly reduced, whereas the activities of pentoxyresorufin beta-depentylase and testosterone 6beta- and 7 alpha-hydroxylases were induced in liver microsomes. 2. Within 24 h after treatment with 50 m kg(-1) flupyrazofos, most enzyme activities were decreased, indicating the interaction of flupyrazofos with cytochrome P450. 3. In Western immunoblotting, cytochrome P4502B1/2 proteins were clearly induced by treatment with flupyrazofos, whereas P4501A1/2 and 2C6 proteins were reduced in liver microsomes. 4. The present results indicate that flupyrazofos modulates the expression of cytochrome P450 in rat.

Surgical treatment of intractable epilepsy accompanying cortical dysplasia

OBJECT

Surgical treatment of cortical dysplasia (CD) together with intractable seizures is challenging because both visualization and localization of the lesion are difficult, correlation with seizure foci requires comprehensive study, and the surgical outcomes reported thus far are unsatisfactory. The authors report their experience in the surgical treatment of CD classified according to a surgical point of view.

METHODS

The definition of CD used in this study was a dysplastic lesion visible on magnetic resonance (MR) images or a lesion that, although not visible on MR images, was diagnosed as moderate-to-severe dysplasia by using pathological analysis. During the last 4.5 years, the authors treated 36 patients with intractable epilepsy accompanied by CD. They divided the 36 cases of CD into four characteristic groups: Group A, diffuse bilateral hemispheric dysplasia; Group B, diffuse lobar dysplasia; Group C, focal dysplasia; and Group D, a moderate to severe degree of CD with a normal appearance on MR images. All but one patient in Group C were monitored in the epilepsy monitoring unit by using subdural electrodes for seizure localization and functional mapping. The incidence of CD among a cohort of 291 patients who had undergone epilepsy surgery at the authors' center during the study period was 12.4%. The mean age of the 36 patients was 21.3 years and the mean age at seizure onset was 8.5 years. The mean follow-up period was 26 months. Twenty-six patients (72.2%) belonged to Engel Class I or II (20 and six, respectively). There were five cases in Group A, nine in Group B, nine in Group C, and 13 in Group D. Patients in Groups A and B were significantly younger at seizure onset and had significantly poorer surgical outcomes compared with patients in Groups C and D (p < 0.05). If outcome is compared on the basis of the extent of removal of CD, patients in whom CD was completely removed had significantly better outcomes than those in whom CD was only partially removed (p < 0.001).

CONCLUSIONS

The authors conclude that intractable epilepsy accompanied by CD can be treated surgically using comprehensive preoperative approaches. Deliberate resective procedures aimed at complete removal of dysplastic tissue ensure excellent seizure control without permanent neurological deficit.

The effect of isochromosome 17q presence, proliferative and apoptotic indices, expression of c-erbB-2, bcl-2 and p53 proteins on the prognosis of medulloblastoma

Medulloblastoma accounts for 20 to 25% of all intracranial neoplasms in children. The significance of the presence of isochromosome 17q (i(17q)), proliferative potential, apoptotic activity, and expression of c-erbB-2, bd-2, and p53 proteins in predicting long-term survival of patients with medulloblastomas was investigated. Twenty children were divided into two groups (favorable and poor outcome groups). Ten children with favorable outcome (FO) were disease-free during the follow-up period (median: 61.5 months). The other ten children with poor outcome (PO) died of disease progression, having a median survival of 18 months. Fluorescent in situ hybridization (FISH) for i(17q), terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL), and immunohistochemistry for Ki-67, c-erbB-2, bcl-2, and p53 proteins was performed in these patients. Nine out of 17 children showed i(17q). There was no difference in the rate of positive i(17q) between the FO and PO groups. The presence of i(17q) was not significantly related to biological factors that we investigated. Unlike the prominent presence of the proliferative potential and p53 expression in children with PO, apoptotic activity and expression of c-erbB-2 and bcl-2 had no correlation with the outcome.

Vascular endothelial growth factor expression under ischemic stress in human meningiomas

Vascular endothelial growth factor (VEGF) is an endothelial cell-specific antigen and angiogenic factor that plays a role in angiogenesis. We analyzed the expression of four VEGF mRNA isoforms in meningiomas. Among 35 meningiomas, 11 came from patients who underwent complete (n=4) or partial (n=7206=189 in all samples. However, the VEGF121 and 165 isoforms were significantly upregulated in samples from patients who underwent partial preoperative embolization. The diffusible VEGF121 isoform may be important for vascularity and edema formation in meningiomas.

Recent progress in biomolecular engineering

During the next decade or so, there will be significant and impressive advances in biomolecular engineering, especially in our understanding of the biological roles of various biomolecules inside the cell. The advances in high throughput screening technology for discovery of target molecules and the accumulation of functional genomics and proteomics data at accelerating rates will enable us to design and discover novel biomolecules and proteins on a rational basis in diverse areas of pharmaceutical, agricultural, industrial, and environmental applications. As an applied molecular evolution technology, DNA shuffling will play a key role in biomolecular engineering. In contrast to the point mutation techniques, DNA shuffling exchanges large functional domains of sequences to search for the best candidate molecule, thus mimicking and accelerating the process of sexual recombination in the evolution of life. The phage-display system of combinatorial peptide libraries will be extensively exploited to design and create many novel proteins, as a result of the relative ease of screening and identifying desirable proteins. Even though this system has so far been employed mainly in screening the combinatorial antibody libraries, its application will be extended further into the science of protein-receptor or protein-ligand interactions. The bioinformatics for genome and proteome analyses will contribute substantially toward ever more accelerated advances in the pharmaceutical industry. Biomolecular engineering will no doubt become one of the most important scientific disciplines, because it will enable systematic and comprehensive analyses of gene expression patterns in both normal and diseased cells, as well as the discovery of many new high-value molecules. When the functional genomics database, EST and SAGE techniques, microarray technique, and proteome analysis by 2-dimensional gel electrophoresis or capillary electrophoresis in combination with mass spectrometer are all put to good use, biomolecular engineering research will yield new drug discoveries, improved therapies, and significantly improved or new bioprocess technology. With the advances in biomolecular engineering, the rate of finding new high-value peptides or proteins, including antibodies, vaccines, enzymes, and therapeutic peptides, will continue to accelerate. The targets for the rational design of biomolecules will be broad, diverse, and complex, but many application goals can be achieved through the expansion of knowledge based on biomolecules and their roles and functions in cells and tissues. Some engineered biomolecules, including humanized Mab's, have already entered the clinical trials for therapeutic uses. Early results of the trials and their efficacy are positive and encouraging. Among them, Herceptin, a humanized Mab for breast cancer treatment, became the first drug designed by a biomolecular engineering approach and was approved by the FDA. Soon, new therapeutic drugs and high-value biomolecules will be designed and produced by biomolecular engineering for the treatment or prevention of not-so-easily cured diseases such as cancers, genetic diseases, age-related diseases, and other metabolic diseases. Many more industrial enzymes, which will be engineered to confer desirable properties for the process improvement and manufacturing of high-value biomolecular products at a lower production cost, are also anticipated. New metabolites, including novel antibiotics that are active against resistant strains, will also be produced soon by recombinant organisms having de novo engineered biosynthetic pathway enzyme systems. The biomolecular engineering era is here, and many of benefits will be derived from this field of scientific research for years to come if we are willing to put it to good use.

Supratentorial primitive neuroectodermal tumor in children: clinical features, treatment outcome and prognostic factors

To investigate clinical features, treatment outcome and prognostic factors of pediatric supratentorial primitive neuroectodermal tumors(ST-PNETs), 28 ST-PNET cases were retrospectively analyzed. The prognostic importance of age, sex, size of tumor, M stage, extent of surgical resection, histological features, immunohistochemical labelling indices (Ki-67, p53), and apoptotic index were assessed. The mean age at diagnosis was 6.8 years, and the male-to-female ratio was 18:10. The presenting symptoms in 22 cases were increased intracranial pressure and focal neurological deficits. Gross total resection was achieved in 17 cases, near-total (>90%) resection in 3, and subtotal in 7; biopsy was performed in 1 case. The mean duration of follow-up was 37 months. For 25 patients who completed planned adjuvant therapy, the 3-year survival rate was 73%. Univariate analysis showed that the presence of tumor necrosis (P=0.002) and extent of resection (P=0.04) correlated with survival. Patients with a high Ki-67 labelling index (>10%) tended to have shorter survival (P=0.095). In multivariate analysis, tumor necrosis showed statistical significance(P=0.03).

Treatment of intracranial nongerminomatous malignant germ cell tumor in children: the role of each treatment modality

To investigate the role of surgical tumor resection, radiotherapy and chemotherapy, the outcome of treatment in 17 children with nongerminomatous malignant germ cell tumor (NG-MGCT) was reviewed. The median follow-up period was 38 months after diagnosis, and the overall 3-year survival rate was 75%. Eleven patients who underwent craniospinal radiation (CSRT) did not receive chemotherapy. In 4 of them more than 90% of the tumor was removed, and they were free of disease at 16, 30, 93 and 111 months after surgery. Among the other 7, who did not undergo tumor resection (n=5) or had considerable residual tumor (n=2), 2 were disease-free at 73 and 88 months after diagnosis, and 5 died of recurrences. Of 6 patients who received cisplatin and etoposide chemotherapy in addition to CSRT, none showed intracranial recurrence, regardless of the extent of removal. The authors believe that multimodal treatment is the preferred choice and that chemotherapy plays an important role, especially when a significant amount of tumor remains after surgery. CSRT plays a major role at least in some patients. If chemotherapy is not feasible, radical removal plus CSRT seems to be an alternative.

A simple method of predicting hormonal outcome in children with intracranial germinoma

Even a small intracranial germinoma (GE) frequently provokes pituitary hypofunction. We evaluated the relationships between preoperative hormonal status and hormonal outcome and between size of suprasellar mass and hormonal outcome in 22 children with intracranial pure GE to determine whether or not these can reflect the degree of hypothalamo-pituitary axis destruction. Preoperative hormonal status was graded from I to IV according to the serum prolactin level (s-PRL) and thyroid function (TF). The hormonal outcome was estimated by the type and the number of hormonal replacement medications taken on the basis of the triple load test and endocrinological examinations at the time of the last follow-up (median period: 43 months). Fifteen of the 22 patients had suprasellar lesions. All 13 patients who had diabetes insipidus (DI) at presentation needed desmopressin acetate (DDAVP) during the follow-up period. The correlation between increment of preoperative grade and the increment in the number of hormones to be replaced was statistically significant (P<0.05). This preoperative grading was a more reliable predictor than the size of suprasellar tumor. In conclusion, preoperative grading by s-PRL and TF test is useful for the prediction of posttreatment hormonal replacement in children with intracranial pure GE.

Intramedullary anaplastic oligodendroglioma in a child

Primary intramedullary anaplastic oligodendroglioma is a rare tumor, only four cases of which have been reported. The authors present the case of a 38-month-old boy with primary intramedullary anaplastic oligodendroglioma. He underwent partial removal of the tumor and spinal radiation therapy. The residual tumor disappeared 12 months after radiation, and 48 months after treatment there was no evidence of recurrence. This case shows that in primary intramedullary anaplastic oligodendroglioma, postoperative radiation therapy confined to the spinal cord can yield an optimal result.

Brain tumor in the first year of life: a single institute study

Brain tumors in infants present special diagnostic and therapeutic challenges. To figure out the clinical features, pathological classification of the tumors and the treatment outcome of infantile brain tumors, 458 children (age<16) with brain tumors were reviewed retrospectively. Among them 21 cases (4.6%) were diagnosed during the first 12 months of life. Two tumors were definitely of congenital origin. The majority of infants with brain tumors presented with increased intracranial pressure. Fourteen tumors were located at the supratentorial area. Sixteen cases had neuroepithelial tumors; astrocytoma (optic pathway), supratentorial primitive neuroectodermal tumor (PNET) and medulloblastoma were found in three cases each. There were two treatment-related mortalities. Compared with the outcomes in older children, the treatment outcome was poorer in medulloblastoma and the optic pathway glioma which showed a higher growth potential. Because of the limited application of postoperative adjuvant therapy, radical surgical removal played a more important role in this age group. The prognosis of patients in whom the tumors could not be totally removed, largely depended on the pathological malignancy of the tumors. Though the treatment outcome was not always dismal, immaturity of the brain, higher growth potential, perioperative risks, limitations in adjuvant therapy, and pessimistic attitude on the part of parents made management more challenging.

Pineal tumors: experience with 48 cases over 10 years

The authors retrospectively reviewed 48 patients treated at Seoul National University Hospital (SNUH) between 1986 and 1995. There were 35 children and 13 adults, accounting for 10.1% of 345 pediatric and 0.68% of 1914 adult brain tumors in SNUH during the same period. The 48 cases consisted of 33 cases of germ cell tumor (69%, GCT); 6 of pineoblastoma (PB, 12.5%); 3 of pineocytoma (PC, 6.3%); 3 of anaplastic astrocytoma (6.3%); 1 of astrocytoma; 1 of glioblastoma; and 1 of ependymoma. The median age was 13 years (range 1-59) and the male-to-female ratio was 3.36:1. The most frequent presenting symptom was due to increased intracranial pressure (90%), followed by Parinaud syndrome or diplopia (50%). Patients with a benign tumor, such as teratoma (TE), astrocytoma, or ependymoma, underwent surgery by the occipital transtentorial approach (OTT) for attempted radical resection without adjuvant therapy, while patients with immature teratoma (imTE), PC, and anaplastic astrocytoma underwent regional radiotherapy (RT) after debulking via OTT. Seven patients with nongerminomatous malignant GCT (NG-MGCT) and 3 with germinoma (GE) underwent craniospinal radiation only, 6 with GE, a NG-MGCT, and 2 with GE+TE received craniospinal radiotherapy (CSRT) after debulking via OTT. Three patients with GE, 4 with NG-MGCT, and 3 with PB underwent radiochemotherapy after debulking via OTT. Forty-four patients were followed up after treatment. The median follow-up period was 36 months. All patients with GE were alive after RT at 36 months (median) of follow-up (range 7-70 months). All with GE+TE and TE were alive. Three patients with PC or astrocytoma were also alive with stable or no evidence of disease. In 1 of the 3 cases of imTE there was a recurrence. However, 4 patients with NG-MGCT died, all of whom had undergone CSRT only; 2 PB patients were alive (12, 19 months), 1 in a moribund status (36 months), and 2 were dead (6, 60 months). The overall mean survival time with pineal tumors was 66 months and the 3-year survival rate was 84% with minimal posttreatment complications. It is concluded that pineal region tumors have male and childhood predominances, and the most common tumor is GCT. The majority of pineal region tumors are malignant. Pineal region tumors can be approached safely and effectively and the surgical complications are mostly transient. Their prognosis is dependent on the pathologies and treatment modalities.

Novel fluoroquinolone antibacterial agents containing oxime-substituted (aminomethyl)pyrrolidines: synthesis and antibacterial activity of 7-(4-(aminomethyl)-3-(methoxyimino)pyrrolidin-1-yl)-1-cyclopropyl-6- fluoro-4-oxo-1,4-dihydro[1,8]naphthyridine-3-carboxylic acid (LB20304)

New pyrrolidine derivatives, which bear an alkyloxime substituent in the 4-position and an aminomethyl substituent in the 3-position of the pyrrolidine ring, have been synthesized and coupled with various quinolinecarboxylic acids to produce a series of new fluoroquinolone antibacterials. These fluoroquinolones were found to possess potent antimicrobial activity against both Gram-negative and Gram-positive organisms, including methicillin resistant Staphylococcus aureus (MRSA). Variations at the C-8 position of the quinolone nucleus included fluorine, chlorine, nitrogen, methoxy, and hydrogen atom substitution. The activity imparted to the substituted quinolone nucleus by the C-8 substituent was in the order F (C5-NH2) > F (C5-H) > naphthyridine > Cl = OMe = H against Gram-positive organisms. In the case of Gram-negative strains, activity was in the order F (C5-NH2) > naphthyridine = F (C5-H) > H > Cl > OMe. The advantages provided by the newly introduced oxime group of the quinolones were clearly demonstrated by their comparison to a desoximino compound 30. In addition, the oxime moiety greatly improved the pharmacokinetic parameters of the novel quinolones. Among these compounds, compound 20 (LB20304) showed the best in vivo efficacy and pharmacokinetic profile in animals, as well as good physical properties. The MICs (microgram/mL) of LB20304, compound 30, and ciprofloxacin against several test organisms are as follows: S. aureus 6538p (0.008, 0.031, and 0.13), methicillin resistant S. aureus 241 (4, 16, and 128), Streptococcus epidermidis 887E (0.008, 0.016, and 0.13), methicillin resistant S. epidermidis 178 (4, 32, and 128), Enterococcus faecalis 29212 (0.063, 0.13, and 1), Pseudomonas aeruginosa 1912E (0.25, 0.5, and 0.13), Escherichia coli 3190Y (0.008, 0.016, and 0.008), Enterobacter cloacae P99 (0.008, 0.031, and 0.008), Actinobacter calcoaceticus 15473 (0.063, 0.13, and 0.25). On the basis of these promising results, LB20304 was selected as a candidate for further evaluation.

Moyamoya disease in adults: characteristics of clinical presentation and outcome after encephalo-duro-arterio-synangiosis

To determine the clinical characteristics and the effectiveness of encephalo-duro-arterio-synangiosis (EDAS) in adulthood-onset Moyamoya disease (MMD), the authors retrospectively reviewed 26 patients suffering from MMD who were admitted to Seoul National University Hospital between 1987 and 1995. When they showed major symptoms, all were more than 16 years-old. The most common presenting symptom was intracranial hemorrhage (ICrH), found in 12 patients or 46% of the total; the second was infarction and transient ischemic attack, each found in seven or 27% of them. Only one patient was found to have seizures, which were associated with a cerebral infarction. The Suzuki angiographic stage 3 and less than stage 3 accounted for 73% of all 52 hemispheres. A total of 15 patients underwent single photon emission computed tomography (SPECT) preoperatively. When the derangement of cerebral perfusion was estimated with four SPECT grades (SG), 70% of their hemispheres revealed normal (SG1) or localized decreased-perfusion (SG2). The other 30% had extensive decreased-perfusion or localized perfusion defects (SG3). There was no case who had extensive perfusion defects (SG4). A total of 17 patients underwent EDAS operations (EDAS group) and nine did not undergo any operation (no-op group). The EDAS group had significantly better clinical outcomes than the no-op group after a 12-month median follow-up period (P < 0.05). The angiographic and SPECT follow-up studies comprised six and seven cases, respectively. There was also satisfactory angiographic revascularization in all follow-up cases and improvement in cerebral perfusion at SPECT follow-up in six of seven cases. It is concluded that the involvement of posterior circulation of MMD is not frequent and cerebral perfusion is preserved in adulthood-onset MMD patients. These findings may explain the reason why hemorrhages are frequent and the late onset of symptoms in adulthood-onset MMD. Surgical treatment with EDAS seems to be effective in adulthood-onset MMD in terms of clinical improvement.

Primary central nervous system lymphoma: variety of clinical manifestations and survival

A retrospective analysis of 23 non-immune compromised patients with primary central nervous system lymphoma (PCNSL) is reported. The patients consist of 14 males and 9 females and the median age is 50 years. Most patients presented with focal neurological deficits or symptoms of increased intracranial pressure (ICP) due to mass effects around the periventricular area. However, there were four cases of diffuse type, one case of intramedullary tumour, and four cases with rapid disease progression. All the patients underwent histological confirmation by craniotomy (16 cases) or stereotactic biopsy (7 cases). The radiation therapy started after histological diagnosis in all and 6 cases received additional chemotherapy. The median survival after diagnosis of overall patients was 23 months. Six patients are in disease free status at a mean of 35 months follow-up. The uni- and multi-variative risk analysis revealed five favourable factors on survival: (1) age less than 60 years (0.05 < p < 0.1); (2)pre-operative Karnofsky performance scale (KPS) > or = 70 (p < 0.05); (3) symptom duration over four weeks (p < 0.05); (4) radiation dosage > or = 5500 cGy (p < 0.05); (5)absence of malignant cells in cerebrospinal fluid (CSF) (p < 0.05). The most frequent site of recurrence was the local area as shown in seven cases out of 11 recurrent cases. But six patients had diffuse recurrence (4 cases), systemic recurrence (2 cases), and drop metastasis (1 case). Although the recurred PCNSL had rapid progression and a grave prognosis, aggressive treatment prolonged the postrecurrence survival time significantly. Our experience suggests that 1) there are various clinical and radiological presentations and progressions of the disease; 2) treatment method should be decided along with the clinical presentation, progression of disease, and prognostic factors; 3) early diagnosis and early detection of recurrence enable the start of definitive treatment when the medical condition is still satisfactory.

An improved synthesis of captopril

An improved synthesis of captopril using methacrylic acid as the starting material is described. Treatment of methacrylic acid (I) with a hydrogen halide gave the 3-halogeno-2-methylpropanoic acids II and III, which were treated with thionyl chloride to yield the corresponding 3-halogeno-2-methylpropanoyl chlorides IV and V. Treatment of IV or V with L-proline yielded the N-(R,S-3-halogeno-2-methylpropanoyl)-L-prolines VI and VII, which were separated into optically pure R- and S-diastereoisomers using dicyclohexylamine. Treatment of halides of VI or VII with methanolic ammonium hydrosulfide gave captopril in 28% yield.

Enzymatic synthesis of phenoxymethylpenicillin using Erwinia aroideae enzyme

Enzymatic synthesis of phenoxymethylpenicillin from 6-aminopenicillanic acid and phenoxyacetic acid methyl ester was attempted by using partially purified alpha-acylamino-beta-lactam acylhydrolase I (ALAHase I) enzyme from Erwinia aroideae NRRL B-138. The reaction rates were carefully followed by determination of 6-aminopenicillanic acid (6-APA), phenoxymethylpenicillin (PNV), phenoxyacetic acid (POA), phenoxyacetic acid methyl ester (POM), and phenoxyacetylglycine (POG) using high performance liquid chromatography. Among the acyl donors tested, POM gave the highest yield (12.2% based on 6-APA). The overall conversion increased almost linearly with an increase in molar ratio of POM to 6-APA up to 4:1. The effects of organic solvents on the overall yield were also evaluated. Some improvement of PNV yield was observed when ethanol, 2-propanol, and acetone were used. ALAHase I was found to carry out three reactions simultaneously: transfer of acyl group to acyl acceptor to form semisynthetic beta-lactam antibiotic; hydrolysis of acyl donor in amide or ester bond, and hydrolysis of semisynthetic beta-lactam antibiotic which was produced by the enzyme. It was also observed that the hydrolysis reactions of POM and PNV were irreversible in this reaction system. The optimal pH for the three reactions was different. They were: pH 9.0 for POM hydrolysis, 6.8 for the transfer of phenoxyacetyl group to 6-APA, and 6.0 for the PNV hydrolysis. The apparent Km values for POM, 6-APA and PNV were estimated as 33, 25 and 31 mM, respectively.

Biochemical properties of penicillin amidohydrolase from Micrococcus luteus

Some biochemical properties of whole-cell penicillin amidohydrolase from Micrococcus luteus have been studied. This whole-cell enzyme showed its maximal activity at 36 degrees C at pH 7.5. It was found that the activation energy of this enzyme was 8.03 kcal (ca. 33.6 kJ) per mol, and this amidohydrolase showed first-order decay at 36 degrees C. The penicillin amidohydrolase was deactivated rapidly at temperatures above 50 degrees C during storage or preincubation for 24 h. The Michaelis constant, Km, for penicillin G was determined as 2.26 mM, and the substrate inhibition constant, Kis, was 155 mM. The whole-cell penicillin amidohydrolase from M. luteus was capable of hydrolyzing penicillin G, penicillin V, ampicillin, and cephalexin, but not cephalosporin C and cloxacillin. This whole-cell enzyme also had synthetic activity for semisynthetic penicillins or cephalosporins from D-(--)-alpha-phenylglycine methyl ester and 6-alpha-aminopenicillanic acid or 7-amino-3-deacetoxycephalosporanic acid.