Computer Assisted Planning for Curved Laser Interstitial Thermal Therapy

Laser interstitial thermal therapy (LiTT) is a minimally invasive alternative to conventional open surgery for drug-resistant focal mesial temporal lobe epilepsy (MTLE). Recent studies suggest that higher seizure freedom rates are correlated with maximal ablation of the mesial hippocampal head, whilst sparing of the parahippocampal gyrus (PHG) may reduce neuropsychological sequelae. Current commercially available laser catheters are inserted following manually planned straight-line trajectories, which cannot conform to curved brain structures, such as the hippocampus, without causing collateral damage or requiring multiple insertions. The clinical feasibility and potential of curved LiTT trajectories through steerable needles has yet to be investigated. This is the focus of our work. We propose a GPU-accelerated computer-assisted planning (CAP) algorithm for steerable needle insertions that generates optimized curved 3D trajectories with maximal ablation of the amygdalohippocampal complex and minimal collateral damage to nearby structures, while accounting for a variable ablation diameter ( 5-15mm). Simulated trajectories and ablations were performed on 5 patients with mesial temporal sclerosis (MTS), which were identified from a prospectively managed database. The algorithm generated obstacle-free paths with significantly greater target area ablation coverage and lower PHG ablation variance compared to straight line trajectories. The presented CAP algorithm returns increased ablation of the amygdalohippocampal complex, with lower patient risk scores compared to straight-line trajectories. This is the first clinical application of preoperative planning for steerable needle based LiTT. This study suggests that steerable needles have the potential to improve LiTT procedure efficacy whilst improving the safety and should thus be investigated further.

Molecular insights into the development of hepatic metastases in colorectal cancer: a metastasis prediction study

OBJECTIVE

Colorectal cancer is presently the third most commonly diagnosed cancer in the United States. In this study, we identified molecular differences between hepatic and non-hepatic metastases in colorectal cancer and evaluated their prognostic significance.

MATERIALS AND METHODS

We downloaded primary data from the NCBI Gene Expression Omnibus (GSE6988, GSE62321, GSE50760, and GSE28722). To identify the molecular differences, we used the Significance Analysis of Microarray method. We selected nine prognostic genes (SYTL2, PTPLAD1, CDS1, RNF138, PIGR, WDR78, MYO7B, TSPAN3, and ATP5F1) with hepatic metastasis prediction score in colorectal cancer (hereafter referred to as LASSO Score). We confirmed the prognostic significance of the LASSO Score by using Kaplan-Meier survival analysis, multivariate analysis, the time-dependent area under the curve (AUC) of Uno's C-index, and the AUC of the receiver operating characteristic curve at 1-5 years.

RESULTS

Survival analysis revealed that a high LASSO Score is associated with a poor prognosis in colorectal cancer patients with hepatic metastases (p = 0). Analysis of C-indices and AUC values from the receiver operating characteristic curve further supported this prediction by the LASSO Score. Multivariate analysis confirmed the prognostic significance of the LASSO Score (p = 1.13e-06).

CONCLUSIONS

This study reveals the biological mechanisms underlying hepatic metastases in colorectal cancer and will help in developing targeted therapies for colorectal cancer.

Novel GP64 envelope variants for improved delivery to human airway epithelial cells

Lentiviral vectors pseudotyped with the baculovirus envelope protein GP64 transduce primary cultures of human airway epithelia (HAE) at their apical surface. Our goal in this study was to harness a directed evolution approach to develop a novel envelope glycoprotein with increased transduction properties for HAE. Using error-prone PCR, a library of GP64 mutants was generated and used to prepare a diverse pool of lentiviral virions pseudotyped with GP64 variants. The library was serially passaged on HAE and three GP64 mutations were recovered. Single-, double- and the triple-combination mutant envelope glycoproteins were compared with wild-type GP64 for their ability to transduce HAE. Our results suggest that lentiviral vectors pseudotyped with evolved GP64 transduced HAE with greater efficiency than wild-type GP64. This effect was not observed in primary cultures of porcine airway epithelial cells, suggesting that the directed evolution protocol was species specific. In summary, our studies indicate that serial passage of a GP64 mutant library yielded specific variants with improved HAE cell tropism, yielding tools with the potential to improve the success of gene therapy for airway diseases.

The effects of prophylactic bolus phenylephrine on hypotension during low-dose spinal anesthesia for cesarean section

BACKGROUND

Continuously infused phenylephrine is frequently used to reduce the incidence of hypotension in women undergoing cesarean section under spinal anesthesia, but less is known about the prophylactic bolus method. We evaluated three prophylactic bolus doses of phenylephrine during low-dose spinal anesthesia for cesarean section.

METHODS

One-hundred-and-eighty-four patients were randomized to receive 0.9% saline 2mL (Control Group) or phenylephrine 1.0μg/kg (PHE1 Group), 1.5μg/kg (PHE1.5 Group), or 2.0μg/kg (PHE2 Group) immediately after induction of combined spinal-epidural anesthesia. Maternal blood pressure and heart rate were recorded at 1-min intervals until delivery. Hypotension, defined as systolic blood pressure <80% of baseline, was treated with rescue doses of phenylephrine 100μg at 1-min intervals until hypotension resolved. The incidence of nausea, vomiting, bradycardia, and hypertension, as well as Apgar scores and umbilical blood gases, were recorded.

RESULTS

The incidence of hypotension was 71.7% (33/46) in the Control Group, 68.9% (31/45) in the PHE1 Group, 37.0% (17/46) in the PHE1.5 Group and 45.7% (21/46) in the PHE2 Group (P=0.001). The total rescue dose of phenylephrine was greater in the Control Group than those in the PHE1.5 Group (P<0.05) and PHE2 Group (P<0.05). The incidence of hypertension increased as the dose of prophylactic phenylephrine increased (P<0.001) and was highest in the PHE2 group (37%). Other variables did not differ among the four groups.

CONCLUSIONS

Under the conditions of this study, prophylactic bolus injection of phenylephrine 1.5μg/kg was a suitable alternative method for reducing the incidence of hypotension during low-dose spinal anesthesia for cesarean section.

Antimicrobial activity of the constituents of Smallanthus sonchifolius leaves against methicillin-resistant Staphylococcus aureus

BACKGROUND AND OBJECTIVES

Methicillin-resistant Staphylococcus aureus (MRSA) has been a serious problem as its infection is associated with higher mortality and increase cost worldwide. In the present study, the antibacterial activity of enhydrin, polymatin B, allo-schkuhriolide from the leaves of Smallanthus sonchifolius was investigated.

MATERIAL AND METHODS

Enhydrin, polymatin B, allo-schkuhriolide from the leaves of Smallanthus sonchifolius were tested for antimicrobial activity using micro dilution broth method against 2 strains of ATCC 33591, ATCC 25923 and 15 strains of clinical isolates MRSA.

RESULTS

The antibacterial activity of Smallanthus sonchifolius can safely be attributed to enhydrin as polymatin B, and allo-schkuhriolide are not showing any activity against Staphylococcus aureus strains. The enhydrin showed good antibacterial activity against all tested strains (MIC = 125-500 microg/ml).

DISCUSSION

These results suggest that only enhydrin can be considered as an antibacterial drug against MRSA.

Anti-angiogenic activities of gliotoxin and its methylthioderivative, fungal metabolites

In the search for new naturally occurring angiogenic inhibitor, we found that culture broths from two unidentified fungal strains exerted potent inhibitory activities on capillary-like tube formation of human umbilical vein endothelial cells (HUVEC) in vitro. Two active compounds were isolated by bioassay-guided separation and their structures were identified as gliotoxin (1) and its derivative methylthiogliotoxin (2) by spectroscopic analyses. These compounds significantly inhibited the migration of HUVEC assessed by in vitro wounding migration assay and exhibited at least 10 times more potent inhibition of proliferation of HUVECs as compared with that of cancer cell lines such as HeLa, MCF-7, and KB 3-1 cells. Especially, gliotoxin having disulfide group exerted more potent activities than methylthiogliotoxin, suggesting that gliotoxin could be a useful compound for further study as an anti-angiogenic agent.

Kaurane diterpenes from Isodon japonicus inhibit nitric oxide and prostaglandin E2 production and NF-kappaB activation in LPS-stimulated macrophage RAW264.7 cells

A methanolic extract of the whole plant of Isodon japonicus (Labiatae) showed potent inhibition on the LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production in RAW264.7 cells. Four known kaurane diterpenes were isolated by activity-guided fractionation and their structures were identified as kamebanin (1), kamebacetal A (2), kamebakaurin (3), excisanin A (4). All compounds also inhibited the LPS-induced NF-kappaB activation as assessed by NF-kappaB reporter assay and electrophoretic mobility shift assay (EMSA). Compounds 2-4 showed comparable inhibitory effects on the LPS-induced production of NO and PGE2, and activation of NF-kappaB without affecting cell viability. These results suggest that kaurane diterpenes could exert their inhibitory effects on the production of NO and PGE2 through the suppression of NF-kappaB activation, and be partially responsible for the anti-inflammatory activities of the genus Isodon.

Antioxidant benzoylated flavan-3-ol glycoside from Celastrus orbiculatus

A new flavan-3-ol glycoside, (-)-epicatechin-5-O-beta-D-glucosyl-3-benzoate (1), and two known compounds, (-)-epicatechin and (-)-epiafzelechin, were isolated from an EtOAc extract of Celastrus orbiculatus aerial parts that exhibited significant antioxidant effect in a 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical assay. The structure of 1 was elucidated by spectroscopic analyses, and compound 1 and its aglycon, (-)-epicatechin-3-benzoate (2), were found to be moderately active as antioxidants in the DPPH assay.

Kinetic resolution of racemic alpha-methyl-beta-propiothiolactone by lipase-catalyzed hydrolysis

Kinetic resolution of racemic alpha-methyl-beta-propiothiolactone (rac-MPTL) using lipases in organic solvent was studied. The lipase from Pseudomonas cepacia (PCL) showed the highest (S)-enantioselectivity (E > 100), and cyclohexane containing 1% (v/v) buffer was identified as the best reaction medium for maintaining high enantioselectivity as well as high reaction rate. While the substrate inhibition was not observed up to 300 mM rac-MPTL, severe product inhibition was observed even at 50 mM racemic 3-mercapto-alpha-methyl propionic acid (rac-MMPA), which made the use of high substrate concentration difficult. To overcome the product inhibition, the products, (R)-MMPA, were neutralized by addition of a dilute basic solution. Although the resolution reaction proceeded further by the base titration, the enantioselectivity of the reaction decreased as a result of nonenantioselective hydrolysis of rac-MPTL in the basic solution. Under these conditions, 200 mM rac-MPTL was successfully resolved to above 95% ee(S) with 53% conversion.

(-)-Epiafzelechin: cyclooxygenase-1 inhibitor and anti-inflammatory agent from aerial parts of Celastrus orbiculatus

An inhibitor of cyclooxygenase (COX)-1 activity of prostaglandin H2 synthase was isolated from aerial parts of Celastrus orbiculatus Thunb. (Celastraceae), an oriental folk medicine for rheumatoid arthritis by activity-guided column chromatographic methods. The COX inhibitor was identified as (-)-epiafzelechin, a member of flavan-3-ols by the structural analysis with HR-EI-mass, 1H-NMR and 13C-NMR spectral data. The compound exhibited a dose-dependent inhibition on the COX activity with an IC50 value of 15 microM. (-)-Epiafzelechin exhibited about 3-fold weaker inhibitory potency on the enzyme activity than indomethacin as a positive control. (-)-Epiafzelechin exhibited significant anti-inflammatory activity on carrageenin-induced mouse paw edema when the compound (100 mg/kg) was orally administrated at 1 h before carrageenin treatment.

Pregnane glycoside multidrug-resistance modulators from Cynanchum wilfordii

The methanol-soluble extracts of the roots of Cynanchum wilfordii showed a significant multidrug-resistance-reversing activity, and four known pregnane glycosides were isolated by bioassay-directed fractionation and separation. Their structures were identified as gagaminin 3-O-beta-D-cymaropyranosyl-(1-->4)-beta-D-oleandropyranosyl- (1-->4)-b eta-D-cymaropyranosyl-(1-->4)-beta-D-cymaropyranoside (1), wilfoside K1N (2), wilfoside C1N (3), and cynauricuoside A (4). In particular, compound 1, at a concentration level of 1 microM, was found to completely reverse the multidrug-resistance of KB-V1 and MCF7/ADR cells to adriamycin, vinblastine, and colchicine.

Acetophenones from the roots of Cynanchum wilfordii H(EMSLEY)

Two acetophenones, cynandione A (1) and cynanchone A (2), were isolated from the roots of Cynanchum wilfordii. Their structures were identified by comparison of their physicochemical and spectral data with reported values.

Comparative studies of adriamycin and 28-deacetyl sendanin on in vitro growth inhibition of human cancer cell lines

The limonoid compound (28-deacetyl sendanin) isolated from the fruit of Melia toosendan SIEB. et ZUCC. was evaluated on anticancer activity. According to a standard in vitro cytotoxicity assay, eight human cancer cell lines and SRB assay were introduced for present evaluation. As a positive standard, adriamycin was tested in parallel. The cell lines were originated from six different organs. In view of dose-response profiles to 28-deacetyl sendanin, the most sensitive cells were SF-539 and PC-3 which were derived from CNS and prostate, respectively. In contrast, all the cell lines responded similarly to adriamycin to give rise to nearly identical dose-response profiles. By comparison of Gl50 between 28-deacetyl sendanin and adriamycin, six cell lines were more sensitive to 28-deacetyl sendanin and two were more resistant. As a result, 28-deacetyl sendanin had more sensitive and selective inhibitory effects on in vitro growth of human cancer cell lines in a comparison with adriamycin.

Determination of oxiracetam in human plasma by reversed-phase high-performance liquid chromatography with fluorimetric detection

Reversed-phase HPLC methodology utilizing pre-column derivatization and post-column reaction fluorimetric detection has been developed and applied to the determination of oxiracetam in human plasma. The method involves preliminary isolation of oxiracetam and internal standard from plasma by solid-phase extraction prior to the formation of their n-propyl carbamate derivatives. The carbamate derivatives were subsequently isolated by solid-phase extraction and subjected to a gradient liquid chromatographic separation on an octadecylsilica column prior to on-line post-column alkaline hydrolysis to produce the corresponding primary amine, which was in turn derivatized with o-phthalaldehyde and 3-mercaptopropionic acid to yield a fluorescent isoindole. The isoindole was then quantified using a fluorescence detector. The method provided an on-column detection limit of 0.5 ng of oxiracetam and was sufficiently sensitive, accurate, and precise to support pre-clinical or clinical pharmacokinetic studies.

Column-switching high-performance liquid chromatographic method for the determination of SK&F 106203 in human plasma after fluorescence derivatization with 9-anthryldiazomethane

A sensitive and selective high-performance liquid chromatographic method was developed for the determination of SK&F 106203 3-(2-carboxyethylthio)-3-[2-(8-phenyloctyl)phenyl]propanoic acid, a potent peptidoleukotriene end organ receptor antagonist, in human plasma. The method involves isolation of SK&F 106203 and the internal standard (SK&F 104736) from plasma samples by liquid-liquid extraction prior to derivatization with 9-anthryldiazomethane. The derivatized samples were first subjected to a solid-phase extraction procedure prior to injection onto a short silica column, which is part of a chromatographic system equipped with an automated column-switching device. Column switching was used to heart-cut the chromatographic zone containing the peaks of interest from this first column and transfer it to an analytical silica column for further chromatographic separation. The peaks were quantified with an in-line fluorometer by measuring the fluorescence emission intensity at 415 nm after excitation at 365 nm. An on-column detection limit of 0.625 ng was achieved for SK&F 106203 by optimizing the derivatization and chromatography conditions. The limit of quantification for SK&F 106203, using 250 microliters of plasma, was 20 ng/ml. Linear response in SK&F 106203/internal standard peak-height ratios was observed for SK&F 106203 concentrations ranging from 10 to 5000 ng/ml of plasma. Precision and accuracy were within 5% across the calibration range. The assay was sufficiently sensitive, accurate, and precise to support pharmacokinetic studies in humans.

Identification of ibopamine metabolites in rat and dog urine

Metabolism of ibopamine (N-methyldopamine-O,O'-diisobutyryl ester) was studied in rats and dogs. The compound was well absorbed in both species when given orally. Most of the administered radiolabel (74-94%) was excreted within 24 hr in urine of both species. The major metabolite in rat urine was 4-glucuronylepinine (63% of the total administered dose). Minor metabolites identified were 4-O-glucuronyl-3-O-methylepinine, 3,4-dihydroxyphenylacetic acid (DOPAC), DOPAC-glucuronide, homovanillic acid (HVA), and HVA-glucuronide. Free epinine and epinine sulfate were detected in the range of less than 1% of the total administered dose. Metabolite patterns in dog urine were different from those of rat urine. The major metabolite was epinine-3-O-sulfate (62% of the total administered dose). Minor metabolites identified in dog urine were DOPAC-sulfate, HVA-sulfate, and free HVA. Free epinine was detected but in the range of less than 1% of the total administered dose. These results showed that ibopamine underwent extensive hydrolysis in vivo to epinine, which was subsequently conjugated and excreted as major metabolites in urine. In addition, side chain degradation of epinine led to minor metabolites, which were excreted in urine as free and conjugated forms. The route of conjugation of ibopamine metabolites is species dependent.

Vascular ischemia of the cervical spine: a review of relationship to therapeutic manipulation

Techniques employed by chiropractors in adjusting fixations of the cervical spine have often been a subject of criticism by other health care professionals. A primary concern is the potential risk of vascular occlusion in this region, subsequent to manipulative therapy. Although rare when compared to the millions of such manipulations given over a corresponding period of years, several reports exist to support the possibility of such an occurrence. Recent evidence, however, suggests that manipulation alone may not be solely contributory. Other extrinsic and intrinsic factors may play important roles in predisposing individuals who seek chiropractic intervention. Such factors are reviewed with the intention of establishing chiropractic professional awareness to such entities and to illustrate the need for a greater corroboration among health care professionals.

Aromatization of 7,8-dichloro-1,2,3,4-tetrahydroisoquinoline by rat liver microsomes

The in vitro aromatization of 7,8-dichloro-1,2,3,4-tetrahydroisoquinoline (DCTQ) has been studied. Incubation of DCTQ with various rat liver subcellular fractions in the presence and absence of cofactors suggested that oxidative reactions catalyzed by microsomal enzymes were involved in this aromatization pathway. In addition to the aromatization product, 7,8-dichloroisoquinoline, three other metabolites were detected in the 9000g supernatant and microsomal incubations. By comparing the chromatographic and spectral data of the metabolites with those obtained for synthetic compounds, these three metabolites were identified as the hydroxylamine, nitrone, and the partially oxidized product (3,4-dihydro) of DCTQ. When added to microsomes, the hydroxylamine and the 3,4-dihydro derivatives were also metabolized to the 7,8-dichloroisoquinoline, and the conversions were NADPH and oxygen dependent. These findings, together with kinetic data, suggested that the aromatization of DCTQ catalyzed by rat liver microsomes was a stepwise oxidative reaction, with N-hydroxylation of DCTQ as the initial step.

Dog liver N-methyltransferase. A drug-metabolizing enzyme

A non-specific N-methyltransferase was demonstrated in dog liver. This enzyme is different from other N-methylating systems, especially in terms of substrate and species specificity. The enzyme catalyzes the methylation of a variety of endogenous and exogenous amines; of the compounds studied, SK&F 64139 (7,8-dichloro-1,2,3,4-tetrahydroisoquinoline) was found to be the best substrate. The enzyme utilized S-adenosylmethionine but not 5-methyltetrahydrofolate as a methyl donor, and it had a pH optimum at 8.0. Study of SK&F 64139 with the partially purified enzyme indicated that this dog liver N-methyltransferase had very low Km and high Vmax values for SK&F 64139. Methylation of SK&F 64139 was not observed with the monkey or rat liver enzyme preparation. This finding is in accordance with the fact that SK&F 64139 is methylated extensively in the dog, but not in other species. The ability of this enzyme to methylate a number of arylalkylamines suggests its possible importance in drug biotransformation.

Gastric antisecretory 9H-xanthen-9-amines

A series of 9H-xanthen-9-amines possessing a wide variety of nitrogen substituents at C-9 was prepared for evaluation of gastric antisecretory activity. These substituents included the acetamidine, imidate, pyrimidine, thiazoline, quinuclidine, 2-hydrazinopyridine, aminopiperidine, aminoalkylimidazole, and aminoalkylpyridine moieties. The majority of compounds in this series inhibited gastric acid secretion when tested orally in the pylorus-ligated rat. Potency was increased by intraduodenal administration and diminished by incubation with gastric juice, suggesting partial degradation of the compounds in the gastric environment. A representative example, 3-(9H-xanthen-9-ylamino)-1-ethylpiperidine, exhibited similar activity in dogs, although no free compound could be detected in the blood. It is therefore hypothesized that this compound is either rapidly bound to tissue and/or metabolized to an active species.

Pharmacokinetics of auranofin in animals

Gold from orally administered auranofin (AF) was absorbed 17-23% in rats and 15-38% in dogs. Gold was highly bound to blood cells and plasma proteins. Gold terminal half life was 1.2-1.8 days in rat blood and plasma (measured for 7 days post dose) and 19.5 days in the dog (measured for 42 days). Excretion of gold (rat and dog) was via feces (84 and 81%) urine (10 and 16%) and bile (3% of dose). Rat tissue levels of gold were highest in the kidney. Evidence indicated that AF was rapidly degraded to triethylphosphine oxide with the remaining molecular fragments postulated to be a protein-gold complex and acetylthioglucose.

Metabolism of 7,8-dichloro-1,2,3,4-tetrahydroisoquinoline, a phenylethanolamine N-methyltransferase inhibitor. II. Species difference in metabolism and synthesis of its metabolites

1. 7,8-Dichloro-1,2,3,4-tetrahydroisoquinoline (DCTQ), a potent reversible inhibitor of phenylethanolamine N-methyltransferase, was well absorbed, readily metabolized and excreted mainly in urine. 2. Its pathways of metabolism in rats and dogs were markedly different. In the dog, N-methylation was followed by N-oxidation to give the corresponding N-methyl-N-oxide as the final metabolic product. This was not observed in the rat. 3. In the rat, major pathways are aromatization of DCTQ to the corresponding isoquinoline and subsequent hydroxylation in the hetero ring to all three possible isomeric hydroxy-isoquinolines. 4. Authentic metabolites were synthesized for comparison with metabolites isolated from urine.

Ticrynafen in anephric patients: effects on uric acid and pharmacokinetics

Ticrynafen was given to 6 anephric patients undergoing maintenance hemodialysis. Ticrynafen was given daily for the 3 days between hemodialyses. Ticrynafen had no effect on the interdialysis rise in serum uric acid levels. Ticrynafen did not accumulate in serum, but levels of metabolites continued to rise over the 3 days. Hemodialysis (5 hr) reduced levels of ticrynafen by 38% but had less effect on metabolite levels. There was no effect on serum cholesterol or triglycerides.