Induction of apoptosis in multi-drug resistant (MDR) human glioblastoma cells by SN-38, a metabolite of the camptothecin derivative CPT-11

 The overexpression of the multidrug resistance (mdr1) gene and its product, P-glycoprotein (P-gp), is thought to limit the successful chemotherapy of human tumors. Recent studies demonstrate that SN-38, a metabolite of the camptothecin (CPT) derivative CPT-11, has antitumor effects on several tumors, but the mechanisms responsible for its cytotoxicity remain unclear. We therefore determined whether SN-38 has cytotoxic effects on MDR human glioblastoma GB-1 cells and non-MDR human glioblastoma U87-MG cells. Furthermore, we determined what role SN-38 plays in the induction of cytotoxicity in these tumor cells. In this study, we demonstrated that SN-38 had significantly stronger antitumor effects on GB-1 and U-87MG cells than did CPT (P<0.01 and P<0.05, respectively). In addition, findings obtained using a DNA fragmentation assay, Hoechst 33258 staining, in situ end-labeling and cell cycle analysis demonstrated that SN-38 induced apoptosis in these tumors. Our results suggest that SN-38 has a stronger antitumor effect on malignant glioma cells regardless of MDR expression than does CPT, and therefore can be considered a new chemotherapeutic agent potentially effective in the treatment of human primary or recurrent malignant gliomas resistant to chemotherapy. Received: 6 October 1995/Accepted 29 June 1996     

Technical aspects of venous stenting in high-grade stenoses using a long guidewire between dual venous access sites

We describe the technical benefits of the dual-access technique for venous stenting in high-grade stenosis. Stents were implanted successfully with this technique in all patients, although the preceding transfemoral interventions had failed. The dual-access technique is useful to facilitate the intervention when the stenoses are too severe to place the stent through just a single access point. Received: 21 October 1998; Revised: 23 February 1999; Accepted: 3 May 1999     

Expression of L1 and TAG-1 in the corticospinal, callosal, and hippocampal commissural neurons in the developing rat telencephalon as revealed by retrograde and in situ hybridization double labeling

In the telencephalon, the corticospinal (CS), callosal, and hippocampal commissural neurons are the major types of neurons that have axons crossing the midline of the brain. To understand the mechanisms involved in crossing the midline structure and to examine whether the expression patterns of L1 and TAG-1 in the commissural neurons are similar to those in the spinal cord, we investigated L1 and TAG-1 expression in these neurons in rats by using a double-labeling technique involving retrograde labeling and in situ hybridization. Expression of L1 messenger RNA was detected in the retrogradely labeled CS projection neurons by 1,1;-dioctadecyl-3,3, 3;,3;-tetramethylindocarbocyanine perchlorate (DiI) injection into the pons at embryonic day (E) 19, but expression of TAG-1 messenger RNA was not detected in these neurons. Also, after their axons crossed the pyramidal decussation, continued expression of L1 but no expression of TAG-1 in the CS projection neurons was shown by an additional double-labeling experiment involving DiI injection into the spinal cord at postnatal day (P) 1. An immunohistochemical study showed that L1 was continuously present in each level of the CS tract at E21 and P3, but TAG-1 immunoreactivity was not found in any level at any stage. Finally, we examined the expression of L1 and TAG-1 messenger RNAs in the callosal and hippocampal commissure neurons after their axons had crossed the midline by using the double-labeling technique. In both cases, hybridization signals of the L1 and TAG-1 messenger RNAs were observed in the retrogradely labeled neurons at P3. These results suggest that the roles of L1 and TAG-1 in the formation of the commissures in the forebrain are different from their roles in the spinal cord.     

Concentrated expression of Ca2+/ calmodulin-dependent protein kinase II and protein kinase C in the mushroom bodies of the brain of the honeybee Apis mellifera L

We have previously used the differential display method to identify a gene that is expressed preferentially in the mushroom bodies of worker honeybees and to show that it encodes a putative inositol 1,4,5-trisphosphate receptor (IP3R) homologue (Kamikouchi et al. [1998] Biochem. Biophys. Res. Commun. 242:181-186). In the present study, we examined whether the expression of some of the genes for proteins involved in the intracellular Ca2+ signal transduction is also concentrated in the mushroom bodies of the honeybee by isolating cDNA fragments that encode the Ca2+/calmodulin-dependent protein kinase II (CaMKII) and protein kinase C (PKC) homologues of the honeybee. In situ hybridization analysis revealed that the expression of these genes was also concentrated in the mushroom bodies of the honeybee brain: The CaMKII gene was expressed preferentially in the large-type Kenyon cells of the mushroom bodies, whereas that for PKC was expressed in both the large and small types of Kenyon cells. The expression of the genes for IP3R and CaMKII was concentrated in the mushroom bodies of the queen and drone as well as in those of the worker bee. Furthermore, the enzymatic activities of CaMKII and PKC were found to be higher in the mushroom bodies/central bodies than in the optic and antennal lobes of the worker bee brain. These results suggest that the function of the intracellular Ca2+ signal transduction is enhanced in Kenyon cells in comparison to other neuronal cell types in the honeybee brain.     

A case of traumatic priapism

We report a case of high flow priapism secondary to arteriovenous fistula produced by perineal trauma in a 43-year-old patient. Diagnosis was based on the result of gasometry in cavernous blood and color doppler sonography. Superselective embolization of the deep artery of the penis was performed with good results. After 6 months of treatment, erection and sexual function were normal. Our case demonstrates that this procedure is a safe and effective therapy for high flow priapism.     

Multivariate analysis of long-term results after an axillobifemoral and aortobifemoral bypass in patients with aortoiliac occlusive disease

BACKGROUND: Controversy still remains regarding the long-term results and indications for axillofemoral bypass (AxFB). A comparison of axillobifemoral bypass (AxBFB) and aortobifemoral bypass (ABFB) was thus conducted to determine whether AxFB is an acceptable alternative vascular procedure to anatomic bypass for high-risk patients. METHODS: Sixty-three patients who underwent a total of 25 AxBFBs and 38 ABFBs for aortoiliac occlusive disease were reviewed retrospectively, and both univariate and multivarate analyses were perfomed. RESULTS: The overall survival was 82.8% at five years. A univariate analysis revealed significantly lower survival rates for patients with limb-threatening ischemia, coronary disease, and cerebrovascular disease. A multivariate analysis disclosed no significant factors influencing survival rates. The overall primary patency was 79.8% at five years. The primary patency rates for AxBFB (67.7% at five years) were significantly lower than for ABFB (88.5% at five years) based on a univariate analysis (p=0.0045). In addition, the secondary patency rates for AxBFB (80.3% at five years) were significantly lower than for ABFB (96.5% at five years, p=0.0025). A multivariate analysis disclosed significantly lower primary patency rates for grafts with a higher angiographic outflow score and simultaneous infrainguinal reconstructive procedures, but the differences between AxBFB and ABFB were not significant. CONCLUSIONS: The survival and primary patency for the AxBFB group were both inferior to the ABFB group, however a multivarate analysis disclosed no significant differences between the two groups. Poor femoral run-off and the presence of synchronous infrainguinal reconstructive procedures significantly affected graft patency, and these factors modulated the patency of AxBFB. AxFB for aortoiliac occlusive disease is therefore considered to be an acceptable procedure in appropriately selected patients.     

Prenatal X-irradiation increases GFAP- and calbindin D28k-immunoreactivity in the medial subdivision of the nucleus of solitary tract in the rat

Glial fibrillary acidic protein- (GFAP) and calbindin D28k-immunoreactivity (IR) were investigated in the medial subdivision of the nucleus of the solitary tract (mNST) of prenatally X-irradiated rats. Pregnant rats were exposed to a single whole-body X-irradiation on day 11 or 16 of gestation at a dose of 1. 3 Gy. The offspring were killed at 7-14 days of age for the immunohistochemical observations. Rat pups showed strong GFAP-IR at the level rostral to the obex when receiving X-rays on day 11 of gestation, with hypertrophy of astrocyte cell bodies and cytoplasmic processes, but weak GFAP-IR when receiving X-rays on day 16 of gestation. Calbindin D28k-IR was stronger in the animals receiving X-rays on day 11 or 16 of gestation compared to that in the control animals. In the present study, the increase of GFAP- and calbindin D28k-IR cells in the mNST might indicate that adaptative mechanisms are taking place to preserve integrated nervous system function and possibly, to provide neuroprotection.