Inhibition of cerebral metabolic and circulatory responses to nitrous oxide by 6-hydroxydopamine in dogs

Purpose

To determine whether cerebral metabolic and circulatory consequences of N₂O result from activation of the sympathoadrenal system. The effects of pretreatment with intracistemal injection of 6-OHDA, which produces chemical sympathectomy, were studied in dogs.

Method

Seven days before measurement dogs were pretreated with intracisternal injection of either saline vehicle (sham-group) or 100 μg· kg^?1 6-hydroxydopamine (6-OHDA group). Cerebral blood flow (CBF) was measured using an electromagnetic flow-meter probe and cerebral metabolic rate for oxygen (CMRO₂) was calculated as the product of CBF and arterial-sagittal sinus blood oxygen content difference [C(a-v)O₂].

Results

In the sham group, N₂O (60%) increased CMRO₂ from 6.11 ± 0.21 ml· 100 g^?1· min^?1 to 7.10 ± 0.39 ml· 100g^?1· min^?1 and CBF from 63 ± 5 ml· 100 g^?1 · min^?1 to 173 ± 26 ml· 100 g^?1· min^?1. In the 6-OHDA group, CMRO₂ did not change during N₂O exposure, whereas CBF increased from 61 ± 3 ml· 100 g^?1· min^?1 to 135 ±19 ml· 100 g^?1· min^?1 but less then in the sham group. The 6-OHDA group displayed a reduction in cortical noradrenaline (NA) concentration from 263.2 ± 35.6 ng·g^?1 to 102.7 ± 16.5 ng· g^?1. Cortical dopamine (DA) concentration was not affected by 6-OHDA administration.

Conclusion

These results suggest that most of the increase in CMRO₂ and, at least a part of, the increase in CBF during N₂O exposure in the sham-group are related to sympathoadrenal-stimulating effects of N₂O.     

Enhanced expression of thymidylate synthase mediates resistance of uterine cervical cancer cells to radiation

It has been shown that there is an inverse relationship between the level of thymidylate synthase (TS) and therapeutic outcomes in patients with malignancies including cervical cancer. To clarify the mechanism of the poor prognosis of cervical cancer with high TS expression, we introduced TS cDNA to the human uterine cervical cancer cell line SKG-II and evaluated the effect of TS expression on its radiosensitivity. After selection, stable transformants of SKG-II cells expressing high level of TS (SKG-II/TS) and control cells (SKG-II/luciferase) were obtained. The level of TS measured by the FdUMP-TS binding assay was significantly higher (p < 0.05) in SKG-II/TS than in control (2.0 +/- 0.1 and 1.3 +/- 0.1 pmol/mg, respectively). No difference was observed in in vitro cell growth or in vivo tumor growth. On evaluation of in vitro radiosensitivity, the 50% growth inhibitory dose (ID(50)) was 3.1 +/- 0.1 Gy in SKG-II/TS and was significantly higher (p < 0.01) than that in control (2.2 +/- 0.1 Gy). From these results, it is suggested that one of the reasons of poor outcome of cervical cancer to radiation is high TS expression.     

Suppression of cell migration in ovarian cancer cells mediated by PTEN overexpression

Peritoneal dissemination is the major progression pathway of ovarian cancer, and its control is important for improvement of the prognosis. PTEN is a tumor suppressor gene, and is known to inhibit cancer cell growth and migration. To investigate the possibility of gene therapy using PTEN for ovarian cancer, we introduced PTEN cDNA into an ovarian cancer cell line HRA carrying wild-type PTEN, and examined the effects in vitro and in vivo. Using PTEN cDNA cloned from a human liver cDNA library, a PTEN expression vector was constructed. This vector was introduced into HRA cells by the standard calcium phosphate precipitation method, and an HRA cell line overexpressing PTEN (HRA/PTEN) was established. On the cell migration test by in vitro scratch wound healing assay, the number of migrating cells was 6.3+/-0.9 cells/mm(2) in HRA/PTEN, which was significantly smaller than that in the control (39.7+/-3.2 cells/mm(2)) (p<0.01). No significant differences were observed in the in vitro cell growth or in vivo tumor growth between HRA/PTEN and the control. The findings described above, show that enhanced expression of PTEN inhibits ovarian cancer cell migration, suggesting that gene therapy approaches using PTEN for control of peritoneal dissemination of ovarian cancer are possible.     

Antigen-specific allogeneic immunotherapy--selective augmentation of GVL effects

Advancement of chemotherapeutic agents and introduction of molecular-targeted therapy have been improving the prognosis of malignant tumors. However, allogeneic hematopoietic cell transplantation (allo-HCT) still remains the sole curative therapy against chemotherapy-resistant hematological malignancies. Once it was found that full engraftment of donor's immune cells could bring sufficient graft-versus-leukemia/lymphoma(GVL)effects, reduced intensity preconditioning regimens that focus only on suppression of the recipient's immune system so as to allow donor graft engraftment have been introduced into clinics. This has expanded the number of patients eligible for allo-HCT, including elderly patients. Nevertheless, overall survival of patients with high-risk malignancies has not been sufficiently improved. Simple enhancement of donor-derived immunity would result in the increased risk of graft-versus-host disease (GVHD). Here, current and future strategies to selectively enhance GVL effects without inducing detrimental GVHD will be discussed in parallel with their background information and basic concepts.     

Evaluation of a rapid qualitative prostate specific antigen assay, the One Step PSA(TM) test

Recently, highly sensitive prostate specific antigen (PSA) kits have been developed and reported to be useful for the early identification of a chemical relapse. However, if the measurement time was short and the cost low, such an assay kit should be sufficient for cancer screening when dealing with a large number of samples. The One Step PSA test uses an immunochromatographic method to qualitatively, not quantitatively, judge a positive or negative result. We confirmed the sensitivity of the kit using purified PSA. Serum specimens from 147 men with or without prostate diseases were tested using the kit. PSA concentration of each serum specimen was independently measured by a quantitative ACS-PSA2 EIA kit (Chiron, cut-off: 2.1 ng/ml). The sensitivity of this kit was determined to be 4 ng/ml. All 33 samples with a value of greater than 4 ng/ml were clearly positive. Of the 94 samples with values less than 4 ng/ml, nine were judged as positive. The remaining 85 cases were judged as completely negative. These results indicate that the sensitivity of the One Step PSA test is 100% and the specificity is 90.4%. Tests using this kit can be easily performed at outpatient clinics or elsewhere. This kit is useful for initial cancer screening, because results can be obtained within 15 min and at a cost lower than that of ordinary PSA kits.     

Effect of interferon α on calcium and bone metabolism in patients with chronic hepatitis

We investigated the changes of natural type of interferon-α (IFNα) on calcium and bone metabolism in patients with chronic hepatitis C. Natural IFNα was injected intramuscularly at daily doses of 6 million units for 2 weeks to 10 patients with chronic hepatitis caused by hepatitis C virus, and followed by 3-times-a-week administration for another 10 weeks. The markers for bone metabolism including serum bone-Gla protein (BGP) concentration and urinary excretion of pyridinolines (pyridinoline and deoxypyridinoline) were measured before and during the treatment. The twelve-week administration of IFNα reduced pyridinoline excretion from 39.7±13.3 (SD) pmol/μ mol · creatinine to 28.3±8.1 pmol/μ mol · creatinine (p<0.06), and that of deoxypyridinoline from 6.51±3.38 pmol/μ mol · creatinine to 3.91±2.07 pmol/μ mol · creatinine (p<0.01), although serum levels of BGP and parathyroid hormone (PTH) did not show any significant changes. The ratio of BGP/urinary pyridinoline increased from 0.098±0.074 to 0.198±0.093 at the end of 12th week (p<0.03), and that of BGP/deoxypyridinoline increased from 0.630±0.502 to 1.550±0.788 at 12th week (p<0.02). Serum aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP) did not change significantly during the study. IFNα reduces bone resorption in contrast with insignificant effects on bone formation in patients with mild to moderate hepatitis. The effects on calcium and bone metabolism may give beneficial effects for patients with high turnover osteoporosis.     

Effects of AVS (1,2-bis(nicotinamido)propane) on platelet function and vascular endothelium

The effects of 1,2-bis(nicotinamido)propane (AVS) on platelet function and vascular endothelium were investigated using various experimental thrombosis and vascular endothelial injury models. Neither in vitro platelet aggregation induced by ADP, collagen or arachidonate nor ex vivo platelet aggregation by ADP or collagen could be antagonized by AVS. On the other hand, AVS prevented mice, rats and rabbits from death induced by acute cerebral or pulmonary thromboembolism following the injection of arachidonate or collagen. These activities were as potent as those of acetylsalicylic acid. The disrupting actions of citrate and/or lipidperoxide (13-hydroperoxy linoleic acid) on endothelium were well inhibited by the pretreatment of AVS. AVS did not inhibit cyclooxygenase, increased prostacyclin (PGI2)/thromboxane A2 (TXA2) ratio in the coupled system of platelets and aortic microsomes. In conclusion, AVS inhibited thrombus formation in vivo while it was ineffective in vitro platelet alone system, which may result from the actions of this agent on both platelets and vascular endothelium. The above-mentioned results clearly show that AVS may be a new potent anti-vascular damaging agent with both endothelium stabilizing and PGI2 enhancing activities.     

Duodenum-Preserving Resection of the Head of the Pancreas: The Significance as a Diagnostic Therapy for the Lesion in the Pancreatic Head

A 75-year-old man who was diagnosed as having mucin-producing pancreatic cystic lesion ofthe main pancreatic duct by duodenoscopic examination was reported. Because of the low malignant potential of such lesions, duodenum-preserving resection of the head of the pancreas was performed, and the intra-operative histological examination showed no malig-nancy of the resected pancreatic head and no other surgical procedures, such as lymph-adenectomy nor pancreato-duodenectomy were necessary. The significance of this case report lies in that a less invasive operation should be selected at first to diagnose whether the lesion is malignant or not, and als0 that the selected operation itself must be sufficient to resect an adequate part of the pancreatic tissue involving the cystic lesion, ifnot malignant. Here, we report the process to select the procedure and the surgical technique.