Uptake of indocyanine green by hepatocytes under inflow occlusion of the liver

BACKGROUND: It is not clear that hepatic venous backflow actually contributes to hepatic tissue oxygenation under inflow occlusion of the liver. In order to prove that substances delivered via the hepatic vein can be utilized and/or metabolized in hepatocytes during inflow occlusion, hepatic uptake in bile and excretion of indocyanine green (ICG) were investigated in pigs. MATERIALS AND METHODS: Animals were divided into two groups: an inflow occlusion (IO) group (N = 6) and a total hepatic vascular exclusion (THVE) group (N = 3) using a bypass. One milligram of ICG per kilogram body weight was administered at the beginning of blood flow occlusion, the retention rate in the blood (ICG R) measured, and the ICG in the hepatic tissue measured by near-infrared (NIR) spectroscopy. Furthermore, the ICG concentration was measured in bile excreted by intermittent perfusion of the liver. RESULTS: ICG R declined with time in both groups; however, ICG R in the IO group decreased much faster than in the THVE group. There were significant differences between the two groups after 30 min of occlusion (P < 0.05). ICG in the hepatic tissue could be detected as a peak at 805 nm 10 min after ICG injection, and the peak became steeper with time. On the other hand, ICG was not detected at all in the hepatic tissue after 180 min in the THVE group. ICG was excreted in the bile after 60 min under IO and increased with time. On the contrary, ICG was not excreted in the bile at all under THVE. There were significant differences between the two groups after 90 min (P < 0.05). CONCLUSION: These results indicate that ICG can be extracted in hepatocytes and excreted in bile under IO of the liver. Consequently, substances such as oxygen and drugs, which are delivered via the hepatic vein, can be utilized and/or metabolized in hepatocytes under IO.     

Exploratory eye movements in schizophrenia

It has been reported that patients with schizophrenia show restricted eye-scanning in comparison with normal controls; however, the precise mechanism underlying the limited eye movement pattern remains unknown. The purpose of this study was to determine the factors affecting restricted eye-scanning in schizophrenic patients by examining exploratory eye movements during demonstration of two different sizes of the S-shaped figure. The second purpose was to determine the effect of the instruction for performance on the restricted viewing pattern in patients with schizophrenia. Eye movements during demonstration of the S-shaped figure of the original or half size were examined in 15 patients with schizophrenia and 15 normal controls using an infrared eye-mark recorder. The patients showed lower search scores than control subjects for both sizes of the figure. The subjects were then instructed to compare a slightly modified figure with the original one. Lower responsive search scores were found for the patients when “fixation point” was defined as a point at which a gaze was held for at least 200 ms, while the patients and control subjects performed equally at the 100-ms setting. Direct instruction to scrutinize the S-shape abolished the difference in the search scores between patients and control subjects at both the 100-ms and 200-ms settings. These findings suggest that the size of the S-figure is not a factor of restricted eye movements, and that the direct instruction improves the visual performance in patients with schizophrenia. Received: 21 February 2000 / Accepted: 15 October 2002 Correspondence to Mié Matsui, Ph. D.     

A nested case-control study of risk factors for adult T-cell leukemia/lymphoma among human T-cell lymphotropic virus type-I carriers in Japan

Objectives: The purpose of this study was to investigate the serological risk factors for development of adult T-cell leukemia/lymphoma (ATL) among human T-cell lymphotropic virus type-I (HTLV-I) carriers. Methods: A nested case–control study was performed. The source population comprised 23,922 subjects who had either visited the outpatient clinic or who had received annual health check-ups at the K Hospital, Nagasaki, Japan, at least once during 1985–1996 (HTLV-I seroprevalence = 16.1%). Markers of HTLV-I infection were examined in stored sera from 29 incident cases of ATL diagnosed during 1985–1997, and 158 controls matched for sex, birth year, date of sample collection, and HTLV-I seropositivity (median follow-up = 6.4 years). Results: In exact conditional logistic regression analysis, high levels of soluble interleukin-2 receptor ( 500 U/ml) and high HTLV-I antibody titers ( 1024) were independently associated with an increased risk of developing ATL (Odds ratio 20.5, 95% confidence interval (CI) 4.5–194 and 2.9, 95% CI 0.98–9.5, respectively). The results remained essentially unchanged when the subjects were restricted to those whose histories were followed for two years or longer. Conclusions: These findings indicate that high soluble interleukin-2 receptor levels and high HTLV-I antibody titers are strong predictors of ATL among carriers of HTLV-I.     

A new regimen for TS-1 therapy designed to minimize adverse reactions by introducing a one-week interval after each two-week dosing session

It has been reported that the response rate to TS-1 of advanced recurrent gastric cancer was the highest rate (46.5%) of effectiveness among anti-cancer agents, but the incidence of adverse reactions to this drug has been found to be as high as 83.2%, with grade 3 or severer reactions occurring in 20.3% of patients. Taking into consideration the post-marketing survey finding that adverse reactions to the drug first appear 2-3 weeks after the start of oral TS-1 therapy, we attempted a new dosing regimen for this drug, wherein each session of therapy lasted for 2 weeks, with a one-week interval between two consecutive sessions (herein-after called "the 2-week regimen"). This regimen was employed based on the expectation that the adverse reactions to the drug would be minimized and that the consecutive dosing period could be prolonged, while keeping the anti-cancer potency at a level similar to that expected with the 4-week dosing regimen with a 2-week interval between sessions (the 4-week regimen). The subjects were 38 patients with advanced or recurrent stomach cancer who were treated with TS-1 at our center between September 1999 and November 2001. Twenty-four patients treated using the 4-week method until January 2001 were taken as a historical control, and compared with 14 patients treated using the 2-week method from February 2001 and afterwards. The incidence of adverse reactions was 71% in the 2-week regimen group against 92% in the 4-week regimen group. The incidence of grade 3 or severe adverse reactions was 8% in the 2-week group and 21% in the 4-week group. Thus, the incidence of adverse reactions was lower in the 2-week group. The percentage of patients who complied with the dosing instructions completely during a 6-month period, as evaluated by the Kaplan-Meier method, was 86% in the 2-week group and 58% in the 4-week group. The response rate, as calculated in patients whose lesions could be evaluated, was 25% in the 2-week group and 19% in the 4-week group. These results suggest that the 2-week regimen may allow safer outpatient drug therapy using TS-1 and merits a trial when considering the QOL of patients. We propose conducting a phase-II multi-center clinical study of this regimen in the near future.     

Induction of different types of uterine adenocarcinomas in Donryu rats due to neonatal exposure to high-dose p-t-octylphenol for different periods

Inappropriate exposure to estrogens in the fetal and/or newborn period can exert irreversible influence, including carcinogenesis on the reproductive system in mammals. The present study was conducted to investigate uterine carcinogenesis in Donryu rats treated neonatally with a high-dose estrogenic compound, p-t-octylphenol (OP) for different exposure periods. Female Donryu rats were subcutaneously administered 100 mg/kg/day OP every other day for the first 5 postnatal days (PNDs 1-5) or the first 2 weeks (PNDs 1-15). They received a single injection of 20 mg/kg N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) into a uterine horn at 11 weeks of age and were examined until 15 months of age. PNDs 1-5 OP-treated rats showed normal development of the female reproductive system, including uterine gland genesis and normal estrous cycling after vaginal opening. The treatment, however, accelerated an earlier occurrence of persistent estrus and increased the number of well differentiated uterine adenocarcinomas as compared with controls. This indicated that PNDs 1-5 OP treatment acts as a delayed modulator of the hypothalamus-pituitary-ovarian hormonal control system and the modulation increased the serum estrogen:progesterone ratio, resulting in induction of uterine tumors. On the contrary, PNDs 1-15 OP treatment demonstrated immediate and irreversible influences on the control system, called 'androgenization', and induced abnormal uterine development manifested by prolonged persistent estrus immediately after vaginal opening and also suppression of uterine gland genesis. In addition, uterine tumor malignancy in morphological and biological property clearly increased in this group although the total number of adenocarcinomas was not increased. The present study provides evidence that neonatal exposure to a high-dose OP enhances uterine carcinogenesis in rats, and the type of uterine tumors is changed by the periods of neonatal exposure to OP, suggesting that the mechanism of uterine tumor development is dependent upon neonatal exposure periods.     

Primary neck management among patients with cancer of the oral cavity without clinical nodal metastases: A decision and sensitivity analysis

BACKGROUND: A standardized neck management strategy for oral cancer patients without clinical nodal metastases remains to be established. Consequently, a decision and sensitivity analysis of two neck management protocols, involving either prophylactic neck dissection or careful observation, was conducted using the Oral Cancer Registry of Kyushu, Japan. METHODS: We calculated probabilities of subclinical nodal metastases and 5-year survival using the registry data. A two-way sensitive analysis was conducted using the probabilities and parameters of the complete nodal metastasis resection rate (x) and a utility rating that describes the health state induced by dissection (y) compared with the neck condition in a careful-observation group. RESULTS: We solved the threshold curve for y and x for the expected utility between the two groups. The results showed that prophylactic neck dissection must guarantee a complete resection of subclinical nodal metastases with no disadvantage to health state to be evaluated as equally satisfactory as careful observation. CONCLUSIONS: Careful observation involving standardized systematic preoperative and postoperative screening of the neck seems preferable to prophylactic neck dissection for oral cancer patients without subclinical nodal metastases.     

Mechanism of the inhibitory effect of OPB-9195 [(+/-)-2-isopropylidenehydrazono-4-oxo-thiazolidin-5-yla cetanilide] on advanced glycation end product and advanced lipoxidation end product formation

The accumulation in uremic plasma of reactive carbonyl compounds (RCO) derived from both carbohydrates and lipids ("carbonyl stress") contributes to uremic toxicity by accelerating the advanced glycation and lipoxidation of proteins. It was previously demonstrated that OPB-9195 [(+/-)-2-isopropylidenehydrazono-4-oxo- thiazolidin-5-ylacetanilide] inhibited the in vitro formation of advanced glycation end products (AGE) in uremic plasma. This study was designed to elucidate the mechanism of action of OPB-9195 by further delineating the AGE and advanced lipoxidation end product (ALE) precursors targeted by this drug. The inhibitory effects of OPB-9195 on the formation of two AGE (N:epsilon-carboxymethyllysine and pentosidine) on bovine serum albumin incubated with various AGE precursors were examined. Inhibition of N:epsilon-carboxymethyllysine and pentosidine formation with OPB-9195 was more efficient than with aminoguanidine. OPB-9195 also proved effective in blocking the carbonyl amine chemical processes involved in the formation of two ALE (malondialdehyde-lysine and 4-hydroxynonenal-protein adduct). The efficiency of OPB-9195 was similar to that of aminoguanidine. When glucose-based peritoneal dialysis fluid was incubated in the presence of OPB-9195, a similar inhibition of AGE formation was observed. The direct effect of OPB-9195 on major glucose-derived RCO in peritoneal dialysis fluids was then evaluated. The effects of OPB-9195 could be accounted for by its ability to trap RCO. The concentrations of three major glucose-derived RCO (glyoxal, methylglyoxal, and 3-deoxy-glucosone) were significantly lower in the presence of OPB-9195 than in its absence. Aminoguanidine had a similar effect. In conclusion, OPB-9195 inhibits both AGE and ALE formation, probably through its ability to trap RCO. OPB-9195 might prove to be a useful tool to inhibit some of the effects of RCO-related uremic toxicity.     

The mouse rasH2/BHT model as an in vivo rapid assay for lung carcinogens.

We have demonstrated the utility of a 9-week in vivo two-stage assay for lung cancer initiating agents, using transgenic mice carrying the human prototype c-Ha-ras gene (rasH2 mice) and butylhydroxytoluene (BHT) as a potent lung promoter (rasH2/BHT model). In the present study, to ascertain appropriate conditions for BHT administration in this model, the effects of exposure on proliferation of alveolar type II cells in male rasH2 mice were examined. Additionally, use of BHT was validated for promotion of urethane (UR) carcinogenesis in male and female rasH2 mice. In a time-course study of a single intragastric administration of BHT at a dose of 400 mg/kg, increased bromodeoxyuridine-labeling index (LI) reached a maximum 3 days after treatment and was still observed after 7 days. In a dose-response study, effects were dose-dependent, the dose of 400 mg/kg causing eight-fold elevation as compared to the control. With repeated administration, whereas the LI was increased dramatically at first, effects gradually diminished with further exposure, and finally six BHT treatments failed to induce cell proliferation. In a two-stage model using UR as the initiator, although up to five consecutive doses of BHT were able to exert continued enhancing effects in terms of adenoma yield, no increment was evident with further treatments. The data overall indicate that a rasH2/BHT model with five weekly administrations of BHT at a dose of 400 mg/kg is most efficacious.     

The Mouse rasH2/BHT Model as an in vivo Rapid Assay for Lung Carcinogens

We have demonstrated the utility of a 9–week in vivo two-stage assay for lung cancer initiating agents, using transgenic mice carrying the human prototype c-Ha- ras gene (rasH2 mice) and butylhydroxytoluene (BHT) as a potent lung promoter (rasH2/BHT model). In the present study, to ascertain appropriate conditions for BHT administration in this model, the effects of exposure on proliferation of alveolar type II cells in male rasH2 mice were examined. Additionally, use of BHT was validated for promotion of urethane (UR) carcinogenesis in male and female rasH2 mice. In a time-course study of a single intragastric administration of BHT at a dose of 400 mg/kg, increased bromodeoxyuridine-labeling index (LI) reached a maximum 3 days after treatment and was still observed after 7 days. In a dose-response study, effects were dose-dependent, the dose of 400 mg/kg causing eight-fold elevation as compared to the control. With repeated administration, whereas the LI was increased dramatically at first, effects gradually diminished with further exposure, and finally six BHT treatments failed to induce cell proliferation. In a two-stage model using UR as the initiator, although up to five consecutive doses of BHT were able to exert continued enhancing effects in terms of adenoma yield, no increment was evident with further treatments. The data overall indicate that a rasH2/BHT model with five weekly administrations of BHT at a dose of 400 mg/kg is most efficacious.