Gene delivery to glioma cells in rat brain by grafting of a retrovirus packaging cell line

Retrovirus vectors only integrate into the genome of dividing cells and can thus be used to selectively infect tumor cells in the adult rat brain. Gene delivery was assessed by using the retrovirus BAG vector, which bears the Escherichia coli lacZ gene under the MoMLV LTR promoter-enhancer element, and by histochemical staining for bacterial beta-galactosidase activity. Direct injection of this vector (90-900 cfu) into the adult rat brain, with or without prior inoculation of C6 glioma cells (2 x 10(5) cells) resulted in labeling of only a few cells as assessed 1 week later. When the psi 2-BAG packaging line was grafted into the brain, labeled psi 2-BAG cells could be found after 1 day, but not after 5 days, following grafting, suggesting that the grafted cells had been rejected and that no endogenous cells had integrated released vector, or that expression of lacZ had been turned off. In contrast, when the psi 2-BAG packaging line was grafted into a brain region, which had been inoculated previously with rat C6 glioma cells (2 x 10(5) cells), beta-galactosidase labeling of these tumor cells, identified by immunocytochemistry for glial fibrillary acidic protein and S100, could be demonstrated 10 days later. Thus, grafting of retrovirus packaging lines into adult brain provides a mean to infect tumor cells in situ. The grafted packaging cells may continue to release retrovirus particles for an extended period, thus infecting more cells at the stage of division appropriate for viral integration, as compared to inoculation of the virus alone. Grafting of retrovirus packaging cell lines could be used to selectively deliver "killer" or "suppressor" genes to tumor cells in the brain to curtail their growth.     

A rubrofusarin gentiobioside isomer from roastedCassia tora

From the roasted seeds ofCassia tora L., a new naphthopyrone glycoside was isolated and characterized as 10-[(β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl)oxyl-5-hydroxy-8-methoxy-2-methyl-4H-naphtho [1,2-b]pyran-4-one(isorubrofusarin gentiobioside). Along with isorubrofusarin gentiobioside, alaternin and adenosine were isolated and identified.     

Batch variation and pharmacokinetics of oral sustained release melatonin-loaded sugar spheres in human subjects

The three different batches of an oral sustained release melatonin (MT) delivery system were prepared by aqueous-based fluid-bed coating of the sugar spheres for the evaluation ofin vitro release characteristics and plasma concentration profiles in human subjects. The MT contents in 20% coated sugar spheres of three batches (B1, B2 and B3) were 3.3+/-0.08, 2.4+/-0.1 and 2.5+/-0.13 mg per gram of coated sugar spheres, respectively. The release profiles of three different batches had a very similar fashion. However, the release half-lives (T(50%)) of MT from B1, B2 and B3 was 3.70+/-0.2, 5.2+/-0.2 and 4.9+/-0.07h, respectively. Plasma concentration profiles of sustained release 0.2mg melatonin-loaded sugar spheres containing 10% immediate release melatonin in gelatin capsules (B1 and B2) were then evaluated in human subjects. Thein vivo plasma concentration profiles of the two batches (B1 and B2) were very similar each other and located between the physiological endogenous ranges. The time to reach the peak concentration (T(max)) was more advanced in case of B1 when compared to B2. However, there was no statistically significant difference in the maximum concentration (C(max)) and the area under the curve (AUC) between B1 and B2. The AUC of melatonin-loaded sugar spheres containing 10% and 20% immediate release MT in human subjects had a good linearity between dose and AUC, regardless of the fraction of immediate release MT, indicating the first order elimination process of MT within these doses. The current oral sustained release MT delivery system may be utilized to treat circadian rhythm disorders if it is proven to be more clinically useful when compared to immediate release MT.     

Endoscopic surgery for obstructive hydrocephalus

Endoscopic surgery is popular in the neurosurgical field. The purpose of this study was to determine the role of endoscopy in obstructive hydrocephalus. From 1989 to 1999, we performed 81 endoscopic third ventriculostomies and 10 septostomies. Seventy-one of 81 operations were performed with endoscopic third ventriculostomy alone and 10 patients had endoscopic third ventriculostomy and ventriculoperitoneal shunt simultaneously. Age distribution varied from 2 months to 62 years of age. Our selection criteria included aqueductal stenosis (39 patients) and obstructive hydrocephalus due to tumor or cyst (42 patients). The most common candidate for endoscopic septostomy was atresia of the foramen of Monro (4 patients). Endoscopic septostomy was also performed to simplify shunting in patient; with multiseptated ventricle due to shunt infection, germinoma, thalamic tumor, craniopharyngioma, cyst and brain abscess. Sixty-five of 71 patients who were treated with endoscopic third ventriculostomy alone showed successful results (91.5%). However, 6 patients had unsatisfactory results and they needed a ventriculoperitoneal shunt. With no mortality, transient surgical complications were observed in 7 patients: 2 transient diabetes insipidus from electrical injury to the pituitary stalk, 1 epidural hematoma from sudden drainage of CSF, 1 delayed intraventricular hemorrhage. 2 obstruction of fenestration site and 1 transient memory disturbance from injury to the fornix. Endoscopic septostomy was useful in simplifying shunting in all cases with complicated hydrocephalus. Endoscopic surgery is straightforward and effective in appropriately selected cases with obstructive by drocephalus.     

The effects of inhibition of the sarcolemmal Ca-ATPase on systolic calcium fluxes and intracellular calcium concentration in rat ventricular myocytes

 The effects of carboxyeosin, an inhibitor of the sarcolemmal Ca-ATPase, were studied on intracellular Ca and membrane currents in isolated rat ventricular myocytes. In the absence of carboxyeosin, 150-ms-duration depolarizing pulses from –40 to 0 mV resulted in an L-type Ca current on depolarization and a Na-Ca exchange ”tail” current on repolarization. The calculated entry of Ca on the L-type current was 1.3 times greater than the efflux via the Na-Ca exchange. The addition of carboxyeosin (20 μM) resulted in either an increase of the Na-Ca exchange current or a decrease of the L-type Ca current such that the Ca entry and efflux were exactly equal. These results suggest that, under control conditions, a carboxyeosin-sensitive Ca-ATPase contributes about 24% of the total Ca efflux from the cell and, therefore, that the sarcolemmal Ca-ATPase has a significant role in regulation of sarcolemmal Ca fluxes. Received: 9 December 1998 / Received after revision: 1 February 1999 / Accepted: 2 February 1999     

Late radiation injury to the temporal lobes: morphologic evaluation at MR imaging

PURPOSE: To study the morphologic characteristics of late radiation injury to the temporal lobes of the brain on magnetic resonance (MR) images. MATERIALS AND METHODS: This was a prospective study involving 34 patients (age range, 37-72 years) with known radiation injury to the temporal lobes from radiation therapy administered 2-10 years previously for nasopharyngeal carcinoma MR imaging was performed with T2-weighted gradient- and spin-echo, gradient-recalled echo, T1-weighted spin-echo, fluid-attenuated inversion-recovery, and T1-weighted postcontrast spin-echo sequences. RESULTS: Radiation injury was present in 57 of the 68 temporal lobes. The white matter lesions in radiation-induced injury were predominantly hyperintense on T2-weighted images, but in 37 (65%) of the 57 lobes, foci with heterogeneous signal intensity consistent with necrosis were detected. In the 57 involved lobes, gray matter lesions were detected in 50 (88%); blood-brain barrier disruption based on parenchymal contrast enhancement, in 51 (89%); and hemosiderin deposits, in 30 (53%). There was a significant correlation between white matter necrosis, gray matter lesions, and blood-brain barrier disruption, all of which were located mainly in the inferior temporal lobes that received the highest radiation dose. CONCLUSION: The lesion components of radiation-induced injury to the temporal lobes at MR imaging were more varied than have been previously described. In addition to the classic white matter lesions, gray matter lesions, blood-brain barrier disruption, and hemosiderin deposition also were frequently seen.     

Induction of food intake by a noradrenergic system using clonidine and fusaric acid in the neonatal chick

To clarify noradrenergic systems on food intake of the neonatal chicks, we examined the effects of i.c.v injection of clonidine (CLON), an alpha2-receptor agonist, and fusaric (5-butylpicolinic) acid (FA), a dopamine (DA)-beta-hydroxylase (DBH) inhibitor. Although a high dose (250 ng) of CLON induced a narcoleptic response and reduced food intake, food intake at 30 min post-injection was enhanced by lower doses (25 and 50 ng) of CLON. Central administration of FA (25, 50 and 100 microg) increased food intake in a dose-dependent fashion. It is suggested that feeding behavior is stimulated by low levels of CLON and decreased by further production of norepinephrine (NE), and FA may play the disturbance of sleeping and then enhance food intake.     

Increased expression of prion protein is associated with changes in dopamine metabolism and MAO activity in PC12 cells

Prion diseases of humans and animals occur following infection with infectious agents containing PrP(Sc) or in situations in which there is a mutation of the prion protein (PrP) gene. The cellular prion protein (PrP(C)) is a sialoglycoprotein that is expressed predominantly in neurons. PrP(C) is converted into a pathogenic form of PrP (PrP(Sc)), which is distinguishable from PrP(C) by its relative resistance to protease digestion. A number of postulates have been advanced for the function of normal PrP (PrP(C)), but this issue has not been resolved. To investigate the function(s) of PrP(C), we established clonal PC12 cell lines, which have elevated PrP(C) expression. The results show that there were alterations in dopamine metabolism and in monoamine oxidase (MAO) activity in transfected PC12 cells that overexpress PrP(C). There was an increase in concentration of DOPAC, a metabolite of dopamine, and in MAO activity in cells overexpressing PrP(C). MAO is involved in oxidative degradation of dopamine (DA). Our data suggest that PrP(C) plays a role in DA metabolism by regulating MAO activity.