Modulation of intestinal P-glycoprotein function by cremophor EL and other surfactants by an in vitro diffusion chamber method using the isolated rat intestinal membranes

Effects of various surfactants on the transport of rhodamine123, a P-glycoprotein (P-gp) substrate, across the isolated rat intestinal membranes were examined by an in vitro diffusion chamber system. The jejunal serosal-to-mucosal transport (Jsm) of rhodamine123 was more than threefold greater than its mucosal-to-serosal transport (Jms), suggesting that the net movement of rhodamine123 across the rat jejunum was preferentially secretory direction. There exists a regional difference in the intestinal transport of rhodamine123 and the secretory directed transport was remarkably observed in the jejunum. The Jsm/Jms ratio of rhodamine123 decreased in the presence of 0.3 mM verapamil and 10 mM sodium azide (NaN3) + 1 mM sodium fluoride (NaF), confirming that rhodamine123 might be secreted from the intestinal tissue into the lumen by a P-gp-mediated efflux system. Nonionic surfactants [0.1% Cremophor EL, Tween 80 and n-dodecyl-beta-D-maltopyranoside (LM)] reduced the Jsm/Jms ratio of rhodamine123, whereas its ratio was not influenced in the presence of 0.1% cationic surfactant (hexadecyltrimethylammonium bromide, C16TAB) and anionic surfactant (sodium dodecyl sulfate, SDS). Therefore, these findings suggested that charge of surfactants was possibly related to the action of these surfactants on the intestinal absorption of P-gp substrates. On the other hand, the transfer of rhodamine123 was not affected by the addition of Cremophor EL to the serosal side. Because the c.m.c. of Cremophor EL is 0.0095 w/v%, interactions between rhodamine123 and the micellar form of Cremophor EL may decrease the P-gp-mediated efflux of rhodamine123 at higher concentrations. In the kinetic analysis, the Vmax value (nmol/min/g wet tissue) of rhodamine123 decreased, although the Km value (mM) was constant in the presence of Cremophor EL. Therefore, Cremophor EL inhibited the efflux transport of rhodamine123 in a noncompetitive manner. Cremophor EL did not affect the transport of [14C]Gly-Sar and [3H]3-O-methyl-D-glucose, suggesting that the action of Cremophor EL might be P-gp specific. These findings indicated that nonionic surfactants including Cremophor EL and Tween 80 may be useful pharmaceutical excipients for inhibiting the function of P-gp, thereby increasing the intestinal absorption of various drugs, which are secreted by a P-gp-mediated efflux system in the intestine.     

Adjuvant chemotherapy of paclitaxel plus carboplatin in uterine corpus cancer--comparison with cisplatin, adriamycin plus cyclophosphamide

The therapeutic efficacy and adverse reactions were compared between 14 patients who received TJ therapy using paclitaxel (PTX) and carboplatin (CBDCA) and 39 who received CAP therapy using cyclophosphamide (CPA), doxorubicin (DXR) and cisplatin (CDDP) as postoperative chemotherapy for cancer of the uterine body. In TJ therapy, PTX (175 mg/m(2)) and CBDCA (AUC 5) were administered on Day 1 (every 3 weeks), while in CAP therapy, CPA (500 mg/m(2)), DXR (40 mg/m(2)) and CDDP (50 mg/m(2)) were administered on Day 1 (every 4 weeks). Grade 3 or more severe hematotoxicity included leukocytopenia (incidence in the TJ and CAP groups: 71.4% and 64.1%, respectively), neutropenia (100%, 87.1%), thrombocytopenia (0%, 12.8%), and anemia (0%, 20.5%). No significant differences were noted between the two groups. Grade 3 or severe non-hematologic toxicities included nausea (0%, 15.4%) and vomiting (0%, 12.8%) with significantly higher incidence in the CAP therapy group (p=0.0000736, p=0.000736), peripheral sensory disturbance (7.1%, 0%) and arthralgia (7.1%, 0%) with significantly higher incidence in the TJ therapy group (p=0.00129, p=0.00000538). The survival rate and disease-free survival rate showed no significant differences between the two groups. TJ therapy is thought to be as effective as CAP therapy, and can be safely conducted, although precautions are required regarding arthralgia and neuropathy.     

Concurrent chemoradiotherapy for locally unresectable head and neck cancer

In patients with locally unresectable head and neck cancer with large nodal involvement, the expected five-year survival is as low as 1-2%. To improve the prognosis of these patients, we studied the usefulness of concurrent chemoradiotherapy in a phase II trial. Between September 1996 and May 1999, thirty-five patients with locally unresectable head and neck cancer were administered concurrent chemoradiotherapy consisting of low-dose and long-term treatment with cisplatin (CDDP) plus 5-fluorouracil (5FU), or (L-CF); the L-CF regimen consisted of CDDP, 3 mg/m2 on 5 days of the week and 5FU, 150 mg/m2 as a 24-hour infusion on 5 days of the week. Concurrently, conventional radiotherapy was given up to total dose of around 60 Gy. In the 33 patients evaluable for response, 17 complete and 9 partial responses were noted, with an overall response rate of 79%. Oral mucostis and myelosuppression were the major side effects and mucositis was a dose limiting toxicity. This study demonstrates increase in survival among the responders (complete + partial) in the concurrent chemoradiotherapy setting. However 8 local relapses were eventually noted in the 17 complete responders. We concluded that this treatment strategy was beneficial in patients with locally unresectable head and neck cancer.     

Late-night salivary cortisol as a screening test for the diagnosis of Cushing's syndrome in Japan

Measurement of late-night and/or midnight salivary cortisol currently used in US and European countries is a simple and convenient screening test for the initial diagnosis of Cushing's syndrome (CS). Unfortunately, this test has not been widely used in Japan. The purpose of this study was to evaluate the usefulness of the measurement of late-night salivary cortisol as a screening test for the diagnosis of CS in Japan. We studied 27 patients with various causes of CS, consisting of ACTH-dependent Cushing's disease [5] and ectopic ACTH syndrome [4] and ACTH-independent adrenal CS [11] and subclinical CS [7]. Eleven patients with type 2 diabetes and obesity and 16 normal subjects served as control group. Saliva samples were collected at late-night (23:00) in a commercially available device and assayed for cortisol by radioimmunoassay. There were highly significant correlations (P<0.0001) between late-night serum and salivary cortisol levels in normal subjects (r = 0.861) and in patients with CS (r = 0.788). Late-night salivary cortisol levels in CS patients (0.975 +/- 1.56 microg/dl) were significantly higher than those in normal subjects (0.124 +/- 0.031 microg/dl) and in obese diabetic patients (0.146 +/- 0.043 microg/dl), respectively. Twenty-five out of 27 CS patients had late-night salivary cortisol concentrations greater than 0.21 microg/dl, whereas those in control group were less than 0.2 microg/dl. Receiver operating characteristic curve (ROC) analysis showed that the cut-off point of 0.21 microg/dl provides a sensitivity of 93% and a specificity of 100%. Therefore, it is concluded that the measurement of late-night salivary cortisol is an easy and reliable noninvasive screening test for the initial diagnosis of CS, especially useful for large high-risk populations, such as diabetes and obesity.     

Impact of venous invasion on the efficacy of adjuvant chemotherapy in elderly patients with stage III colorectal cancer

One of the reasons for the underuse of adjuvant chemotherapy in elderly patients with stage III colorectal cancer is a small survival benefit. This retrospective study sought to identify the predictive factors for elderly patients who could obtain a sufficient survival benefit. We reviewed the data of 1354 elderly patients (aged ≥70 years) with stage III colorectal cancer who underwent complete resection between January 1997 and December 2006. The efficacy of adjuvant chemotherapy was assessed, and the risk factors for recurrence were determined. The efficacy of adjuvant chemotherapy was also assessed after stratification for the above-mentioned risk factors for recurrence. There was a tendency for adjuvant chemotherapy to be effective in elderly patients (hazard ratio 0.84; 95% CI 0.70–1.01). Age, tumor location, pathology findings, tumor depth, venous invasion and lymph node metastasis were identified to be independent risk factors for recurrence by univariate and multivariate analyses. Among these factors, adjuvant chemotherapy was much effective in the elderly patients with high venous invasion (v2-3) (hazard ratio 0.69; 95% CI 0.52–0.91). High venous invasion (v2-3) was identified to be a predictive factor for elderly patients with stage III colorectal cancer who gained a sufficient survival benefit.     

Prevalence of and risk factors for low bone mineral density in Japanese female patients with systemic lupus erythematosus

To examine the prevalence of and risk factors for low bone mineral density (BMD) (osteoporosis or osteopenia) in Japanese female patients with systemic lupus erythematosus (SLE). We performed BMD measurements by dual X-ray absorptiometry at the lumbar spine and the hip and collected basic and lifestyle-related, clinical and treatment characteristics among 58 SLE patients. Odds ratios (ORs) and their 95% confidence intervals (CIs) were assessed for associations between low BMD and selected factors among SLE patients. The mean BMD?±?SD was 0.90?±?0.17?g/cm² at the lumbar spine and 0.76?±?0.17?g/cm² at the hip. The prevalence of osteopenia (2.5 SD?<?T score?<?1 SD) was 50.0% and that of osteoporosis (T score?<?2.5 SD) was 13.8% in our SLE patients. After adjustment for age and disease duration, we found the number of deliveries (OR?=?5.58, 95% CI?=?1.31?C26.06; P?=?0.02) to be a risk factor for overall low BMD (T score?<?1 SD) and a maximal dosage of >50?mg/day of oral corticosteroids (OR?=?0.25, 95% CI?=?0.07?C0.91; P?=?0.035) as a preventive factor for low BMD at the lumbar spine. Reduced BMD, especially in spinal trabecular bone, was pronounced in Japanese female patients with SLE, particular in those with a history of delivery. A history of high-dose oral corticosteroids was associated with the preservation of BMD at the lumbar spine, however, further study is needed considering the limited sample size.     

Organization of Mouse DNA Polymerase β Gene Silencer Elements and Identification of the Silencer-binding Factor(s)

Different portions of the 5-upstream region of the mouse DNA polymerase β gene were combined with bacterial chloramphenicol acetyltransferase (CAT) gene of the CAT vector. Transfection of these recombinant plasmids into mouse NIH/3T3 cells has revealed that each of the previously identified two negatively acting regions (silencers I and II) of this gene consists of multiple sub-domains. The distal silencer (silencer I) at around -1.5 kb consists of four sub-domains (-1852 to -1667, -1663 to -1616, -1564 to -1525 and -1355 to -1257). The promoter-proximal silencer (silencer II) at around – 0.5 kb consists of two functional domains (- 681 to – 523 and – 490 to – 447) separated by a neutral region of 33 base pairs. Silencer II functioned efficiently when silencer I was deleted. Conversely, the distal silencer I functioned efficiently when silencer II was deleted. Thus, these silencers functioned redundantly to each other in NIH/3T3 cells. Nucleotide sequence analysis revealed no extensive sequence similarity between these two silencers. Significant sequence similarity is present between a distal portion of silencer II and the c-myc gene silencer, and also between a proximal portion of silencer II and the mouse F9 cell-specific silencer. A protein factor(s) that specifically bound to the silencer elements was detected in nuclear extracts of NIH/3T3 cells and mouse liver in which DNA polymerase β was expressed at a rather low level. The same binding factor(s) can bind to both silencer I and II regions, although its affinity for silencer II is much higher than that for silencer I.     

Rational surgical operations for advanced cancers located in the middle of the stomach

Before 1982, total gastrectomy with pancreaticosplenectomy was performed for advanced gastric carcinoma which exposed to the serosa and was located in the middle of the stomach (M). The results of that surgical treatment were evaluated, and new surgical approaches were expected to provide a much better prognosis to patients. (1) A radical surgical operation, left upper abdominal evisceration + Appleby's method (LUAE + Apl), was tried for Borrmann type 4 gastric cancers from 1983. The 3-year survival after LUAE + Apl (77.9%) was better than that after total gastrectomy with pancreaticosplenectomy (35.0%) (p less than 0.05). In terms of the postoperative condition, no significant differences were observed between both operations. (2) As a conservative operation, total gastrectomy with resection of the spleen and splenic artery (Group A) was compared with total gastrectomy plus pancreaticosplenectomy (Group B) in patients with advanced gastric carcinoma other than Borrmann type 4. The 5-year survival was similar in both groups. The incidence of postoperative disorders was lower in Group A than in Group B (p less than 0.05). LUAE + Apl for Borrmann type 4 and total gastrectomy with resection of the spleen and splenic artery for the other advanced gastric cancers led to good results. These rational surgical operations will be necessary to achieve a good quality of life for the patients.     

Cytoprotective action of histamine against 0.6 N HCl-induced gastric mucosal injury in rats; comparative study with adaptive cytoprotection induced by exogenous acid

We examined the effects of histamine 2HCl (a stimulator of endogenous acid production) and exogenous acid on transmucosal potential difference (PD) and pH of anesthetized rat stomachs, in order to investigate the mechanism underlying the protective action of histamine against 0.6 N HCl-induced gastric mucosal injury in conscious rats. Subcutaneously administered histamine (3-20 mg/kg) dose-dependently produced a decrease in the PD and pH, and it reduced the severity of gastric mucosal injury caused by 0.6 N HCl. Both indomethacin (5 mg/kg, s.c.) and cimetidine (100 mg/kg, s.c.) completely reversed the protection afforded by histamine (20 mg/kg), although the decreased PD and pH responses were unaffected or inhibited, respectively, by indomethacin or cimetidine. Protective action of histamine was also partially mitigated by omeprazole (30 mg/kg, s.c.) which completely abolished histamine-induced acid secretion. On the other hand, exposure of the stomach for 10 min to exogenous acid (0.1-0.35 N HCl) caused a PD reduction and an increase of pH, in a concentration-related manner. The injury caused by 0.6 N HCl was prevented by prior exposure to these low concentrations of HCl, and the degrees of inhibition were associated with the concentration of HCl and the magnitude of PD reduction caused by HCl. The pretreatment with indomethacin, but not cimetidine or omeprazole, significantly antagonized the increased pH and mucosal protection induced by 0.35 N HCl. These results suggest that histamine protected the gastric mucosa against 0.6 N HCl-induced injury by two different ways, mediated with endogenous prostaglandins, (a) mainly through stimulation of H2-receptors and (b) partly through adaptive cytoprotection induced by acid.     

Tc-99m(V) DMSA uptake in cardiac amyloidosis.

Tc-99m(V) DMSA scintigraphy was performed on two patients with primary cardiac amyloidosis. Scintigraphy performed (after radionuclide administration) showed accumulation in the myocardium.