Plasticity of central monoaminergic systems during aging]

The locus coeruleus (LC), located within the caudal pontine central gray, is composed of noradrenaline-containing neurons. The axons of these neurons form extensive collateral branches that project widely to many brain sites. The function of the LC is still unclear at present, however, LC neurons are known to exhibit marked axonal regeneration and sprouting in response to brain damage. We investigated the age-related changes in noradrenergic innervations of the frontal cortex, using in vivo electrophysiological techniques and immunohistochemistry. While noradrenergic innervations gradually decreased with age in the frontal cortex, a high degree of sprouting occurred in the LC axon terminals in middle age. Neither the electrophysiological properties of LC neurons nor NA levels in the frontal cortex changed with age. These findings suggested that the LC neurons preserve a strong capacity to remodel their axon terminals even in the aging brain. Exogenous brain-derived neurotrophic factor (BDNF) infusion caused a marked increase in the density of noradrenergic axon in the aged brain, but no trophic action of BDNF was observed in the young or middle-aged brain. The result suggests that BDNF is necessary for the maintenance of noradrenergic innervations in the aged brain.     

Influx and efflux transport of H1-antagonist epinastine across the blood-brain barrier.

We investigated influx and efflux transporters involved in blood-brain barrier transport of the nonsedative H1-antagonist epinastine. The basal-to-apical transport of [14C]epinastine was markedly higher than that in the opposite direction in LLC-GA5-COL150 cells stably transfected with human multidrug resistance (MDR)1 gene. The brain-to-plasma concentration ratio of [14C]epinastine in mdr1a/b(-/-) mice was 3.2 times higher than that in wild-type mice. The uptake of both [3H]mepyramine and [14C]epinastine into immortalized rat brain capillary endothelial cells (RBEC)1 showed temperature and concentration dependence. The kinetic parameters, K(m), V(max), and uptake clearance (V(max)/K(m)), of the initial uptake of [3H]mepyramine and [14C]epinastine by RBEC1 were 150 microM, 41.8 nmol/min/mg protein, and 279 microl/min/mg protein for mepyramine and 10.0 mM, 339 nmol/min/mg protein, and 33.9 microl/min/mg protein for epinastine, respectively. The uptake of [3H]mepyramine and [14C]epinastine by RBEC1 was inhibited by organic cations such as quinidine, amantadine, and verapamil, but not by other organic cations, tetraethyl ammonium, guanidine, and carnitine. Organic anions such as benzoic acid, estrone-3-sulfate, taurocholate, and neutral digoxin were not inhibitory. Furthermore, some cationic H1 antagonists (chlorpheniramine, cyproheptadine, ketotifen, and desloratadine) inhibited the [3H]mepyramine and [14C]epinastine uptake into RBEC1. In conclusion, the present study demonstrated that the combination of efficient efflux transport by P-glycoprotein and poor uptake by the influx transporter, which is identical with that responsible for the uptake of mepyramine, account for the low brain distribution of epinastine.     

O6-Methylguanine-DNA Methyltransferase (MGMT) as a Determinant of Resistance to Camptothecin Derivatives

The precise mechanisms of resistance to camptothecin (CPT)-derived DNA topoisomerase (topo I) inhibitors and the determinants remain unclear. We found that a DNA repair protein, O⁶-methylguanine-DNA methyltransferase(MGMT), participated in resistance to irinotecan hydrochloride (CPT-11), its active metabolite SN-38, and a novel CPT derivative, DX-8951f. In 17 human cancer cell lines, MGMT gene expression level closely correlated with sensitivity to the CPT derivatives, and inhibition of MGMT activity by nontoxic 5 μM O⁶-benzylguanine augmented the drug activity in relation to the MGMT expression levels in 8 cell lines examined. Transfection of pCR/MGMT-sense into U-251MG and pCR/MGMT-antisense into T98G and HEC-46 cells revealed that increased MGMT expression decreased the sensitivity to CPT-11, SN-38, and DX-8951f, whereas repressed MGMT expression sensitized cells to the drugs. Western analysis revealed that treatment of MGMT -expressing T98G cells with the drugs caused a decrease of both MGMT and topo I in a dose-dependent manner. Although, in the transfectants, MGMT expression did not so closely correlate with the sensitivity to drugs as to nimustine hydrochloride (ACNU), MGMT is probably an important resistance determinant to CPT derivatives, and may play some role in the topo I-mediated DNA damage and/or the repair process.     

Effectiveness of doxifluridine (5′-DFUR)/docetaxel against advanced/recurrent gastric cancer showing resistance to various anticancer drug regimens

A 58-year-old man was diagnosed as having type 3 gastric cancer (poorly differentiated adenocarcinoma). He underwent total gastrectomy with splenectomy, as well as D3 dissection, and received postoperative chemotherapy combining oral uracil and futrafur (UFT) with cisplatin (CDDP), but results showed recurrence of multiple abdominal lymph node metastases around the aorta. He therefore received various anticancer drug regimens (irinotecan [CPT-11]/CDDP; 1 M tegafur-0.4 M gimeracil-1 M oteracil potassium [TS-1], methotrexate (MTX)/5-fluorouracil); however, final results showed growth of lymph node metastasis and simultaneous worsening of his general condition. The patient then received combined administration of doxifluridine (5′-DFUR)/docetaxel (5′-DFUR, 1000 mg/body [666.7 mg/m ² ], given by consecutive daily administration, orally, for days 1–14; and docetaxel, 80 mg/body [60 mg/m ² ], on day 8, by venous drip, every 3 weeks). Three courses of this regimen resulted in approximately 90% reduction of the abdominal lymph node size, disappearance of the right cervical lymph node metastasis, reductions of the levels of two tumor markers (carcinoembryonic antigen [CEA] and carbohydrate antigen [CA]19-9), and improvement of his general condition. In total, seven courses of the regimen were carried out. The patient died on day 298 after starting this combined regimen and showed a response period of 126 days. The primary toxicity identified was neutropenia (grade 4), as well as other low-grade (grade 1, 2) hematological and nonhematological toxicities. In the field of gastric cancer treatment, especially for patients showing multiple resistance to anticancer drugs, an effective therapy is critically needed. Received: January 15, 2002 / Accepted: July 8, 2002 Offprint requests to: A. Sato     

Relation between the insulin lowering rate and changes in bone mineral density: Analysis among subtypes of type 1 diabetes mellitus

Aims/IntroductionThe bone mineral density in patients with type 1 diabetes mellitus is reduced due to impaired insulin secretion. However, it is unclear whether the rate of bone mineral density reduction is affected by the type 1 diabetes mellitus subtype. This study aimed to clarify the difference in bone mineral density across type 1 diabetes mellitus subtypes: slowly progressive (SP), acute‐onset (AO), and fulminant (F).MethodsThis was a retrospective, single‐center, cross‐sectional study conducted on 98 adult type 1 diabetes mellitus patients. The main outcome included the bone mineral density Z‐score (BMD‐Z) measured at the lumbar spine and femoral neck.ResultsThe lumbar spine BMD‐Z was lower in the acute‐onset than in the slowly progressive subtype (P = 0.03). No differences were observed when compared with the fulminant subtype. The femoral neck BMD‐Z tended to be higher in the slowly progressive than in the acute‐onset and fulminant subtypes. Multiple regression analyses showed that the lumbar spine BMD‐Z was associated with subtypes (AO vs SP) (P = 0.01), but not subtypes (F vs SP), adjusted for sex, duration, retinopathy, and C‐peptide immunoreactivity (CPR). When the patients were divided into disease duration tertiles, in the first and second tertiles, the CPR levels were lower in the acute‐onset or fulminant than in the slowly progressive subtype. In contrast, the lumbar spine and femoral neck BMD‐Z differed between the acute‐onset and slowly progressive only in the second tertiles (both P < 0.01), with a similar tendency between the fulminant and slowly progressive subtypes.ConclusionsAmong the type 1 diabetes mellitus subtypes, bone mineral density undergoes time‐dependent changes, which reveals that the bone mineral density decline follows the impaired insulin secretion. These results provide novel insights into the association between the low insulin exposure duration and bone mineral density.     

Arachidonate-enriched triglyceride oil does not promote tumor development in a rat medium-term multi-organ carcinogenesis model

The modifying potential on tumor development of arachidonate-enriched triglyceride oil (ARA-oil) containing approximately 40% arachidonic acid was investigated in a medium-term multi-organ carcinogenesis bioassay using male and female F344 rats. The animals were sequentially given five carcinogens with different target sites in the first 4 weeks, and then administered ARA-oil for 24 weeks at dietary levels of 0% (control), 1.25%, 2.5% or 5.0%. No statistically significant differences in incidences and multiplicities of hyperplastic and neoplastic lesions were showed in the large intestine in either sex. In the liver, kidney, and lung in both sexes, and the mammary gland and uterus in females, tumor promoting potential was not evident with ARA-oil treatment. ARA-oil did not affect the quantitative data for glutathione S-transferase placental form positive foci of the liver. Increased induction of hyperplastic or neoplastic lesions in the urinary bladder and thyroid in ARA-oil-treated groups was without dose dependence. In addition, a second experiment with ARA-oil only administration for 8-week revealed no effects on cellular proliferation in the urinary bladder or thyroid in either sex. These results indicate that ARA-oil has no tumor promoting potential in any organs or tissues initiated with the five carcinogens applied in the present study.     

Inhibition of ocular angiogenesis by diced small interfering RNAs (siRNAs) specific to vascular endothelial growth factor (VEGF)

The effects of diced small interfering RNAs (siRNAs) designed for vascular endothelial growth factor (VEGF) on the expression of VEGF in human retinal pigment epithelial cell line ARPE-19 cells in vitro and on corneal angiogenesis in vivo were examined. The exposure to diced siRNAs significantly reduced the VEGF mRNA expression in ARPE-19 cells with minimal toxicity. In suture-induced corneal angiogenesis models, diced siRNAs minimized the severity of angiogenesis. Histological analysis displayed no particular tissue damage in the conjunctiva where siRNA was injected. The approach using diced siRNAs can be a new tool for various neovascular ocular diseases.     

Comparison of oncological outcomes between trisegmentectomy and lobectomy for non-small cell lung cancer in the left upper division

BackgroundThe left upper lobe is one of the largest lobes in the lungs and is divided into two anatomical units: the upper division (segments 1+2 and segment 3) and lingula (segments 4 and 5). This anatomical classification is similar to that used for the right upper and middle lobes. Although bilobectomy is not recommended for right upper or middle lobe tumors close to the interlobar plane, lobectomy is often performed for tumors located close to the intersegmental plane in the left upper division. To aid in establishing trisegmentectomy as a standard treatment for clinical N0 non-small cell lung cancer (NSCLC) in the left upper lobe, we aimed to re-assess its feasibility based on oncological outcomes according to tumor location.MethodsWe retrospectively analyzed the data of patients with clinical N0 NSCLC in the left upper division who underwent left upper lobectomy or trisegmentectomy between April 2006 and December 2020. After propensity score matching, oncological outcomes were compared between the trisegmentectomy and lobectomy groups. To verify whether trisegmentectomy was indicated regardless of tumor distance from the intersegmental plane, we compared the recurrence-free survival (RFS) rates following trisegmentectomy between patients with tumors ≤20 and >20 mm from the intersegmental plane.ResultsAfter propensity score matching, 46 patients were included in each group. There was no significant difference in the 5-year RFS rate between the lobectomy and trisegmentectomy groups (75.5% vs. 84.0%, P=0.41). In the trisegmentectomy cohort, the 5-year RFS rate did not significantly differ according to tumor distance from the intersegmental plane (≤20 or >20 mm) measured using three-dimensional computed tomography (79.4% vs. 81.2%, P=0.69). Multivariate analysis indicated that tumor distance from the intersegmental plane was not a significant predictor of RFS (hazard ratio: 1.75, 95% confidence interval: 0.52–5.91, P=0.37).ConclusionsOur analysis suggests that oncological outcomes (i.e., RFS rates) following trisegmentectomy for clinical N0 NSCLC in the left upper division are not significantly inferior to those following lobectomy, even if the tumor is located close to the intersegmental plane.     

Clinical evaluations of pituitary apoplexy in incidental nonfunctional pituitary adenomas

Pituitary apoplexy is an uncommon syndrome that often results in spontaneous hemorrhage or infarction of pituitary tumors or glands. We previously reported pituitary apoplexy occurred most frequently in nonfunctional pituitary adenomas among all types of pituitary incidentalomas. In the present study, we aimed to investigate the characteristics of pituitary apoplexy in patients with incidental nonfunctional pituitary adenomas. 65 patients with pituitary incidentaloma were enrolled. All patients underwent clinical/endocrinological/pathological investigations. As a result, 33 patients were diagnosed with nonfunctional pituitary adenomas. Of these, 12.1% of patients had pituitary apoplexy. There was no difference in tumor diameter, age, or sex between the apoplexy and the non-apoplexy groups. However, the liver enzymes aspartate transaminase and alanine aminotransferase were significantly higher, and plasma sodium and chloride levels were significantly lower in the apoplexy group than in the non-apoplexy group (each P < .05). In addition, low-density lipoprotein-cholesterol was significantly higher in the apoplexy group than in the non-apoplexy group (P < .05). Besides, thyroid-stimulating hormone, luteinizing hormone, follicle-stimulating hormone, and prolactin deficiencies were significantly more frequent in the apoplexy group than in the non-apoplexy group (each P < .05), and growth hormone and adrenocorticotropic hormone deficiencies were more frequent in the apoplexy group than in the non-apoplexy group (P = .09 and.08, respectively). Furthermore, tumor diameter was not associated with pituitary apoplexy, whereas thyroid-stimulating hormone, luteinizing hormone, and follicle-stimulating hormone deficiencies were significantly associated with the apoplexy group (each P < .05). Hence, the present study indicated that pituitary apoplexy could not be related to tumor diameter. Moreover, hormonal deficiencies, hepatic dysfunction, hyponatremia or hypochloremia, and dyslipidemia might be indicators of pituitary apoplexy. There could be the possibility the treatment for dyslipidemia prevents pituitary apoplexy.