Malignant hyperthermia in a patient with Graves' disease during subtotal thyroidectomy

We report the case of a 31-year-old man with Graves' disease who manifested malignant hyperthermia during subtotal thyroidectomy. His past medical history and family history were unremarkable. Before surgery, his condition was well controlled with propylthiouracil, beta-adrenergic blocker and iodine. During the operation, anesthesia was induced by intravenous injection of vecuronium and thiopental, followed by suxamethonium for endotracheal intubation. Anesthesia was maintained with nitrous oxide and sevoflurane. One hour after induction of anesthesia, his end tidal carbon dioxide concentration (ET(CO2)) increased from 40 to 50 mmHg, heart rate increased from 90 to 100 beats per min and body temperature began to rise at a rate of 0.3 degrees C per 15 min. Suspecting thyroid storm, propranolol 0.4 mg and methylprednisolone 1,500 mg were administered, which, however, had little effect. Despite the lack of muscular rigidity, the diagnosis of malignant hyperthermia was made based on respiratory acidosis. Sevoflurane was discontinued and dantrolene was given by intravenous bolus. Soon after the treatment, ET(CO2), heart rate and body temperature started to fall to normal levels. His laboratory findings showed abnormally elevated serum creatine phosphokinase and myoglobin but normal thyroid hormone levels. Since dantrolene is efficacious in thyrotoxic crisis and malignant hyperthermia, an immediate intravenous administration of dantrolene should be considered when a hypermetabolic state occurs during anesthesia in surgical treatment for a patient with Graves' disease.

The cytotoxic effects of bile acids in crude bile on human pancreatic cancer cell lines

Pancreatic cancer frequently causes extrahepatic cholestasis. To identify the direct effects of bile acids in jaundiced serum on pancreatic cancer, the proliferation of PANC-1 and MIA PaCa-2 cells as well as the ultrastructural alteration of PANC-1 cells cultured in crude bile modified media were studied. The growth of these cells in the RPMI-1640 media with or without 1%, 2%, and 4% of the refined crude bile was assessed after 48 and 96 h of incubation. The ultrastructure of PANC-1 cells was investigated by scanning and transmission electron microscopy after 24 and 48 h of incubation. The proliferation of both cell lines in the bile-treated media was greatly inhibited. The inhibitory rates of bile on PANC-1 ranged from 24.1% +/- 3.3% to 66.9% +/- 6.6% (P < 0.01) and those on MIA PaCa-2 ranged from 16.7% +/- 3.8% to 50.7% +/- 5.5%. (P < 0.01). When the bile-added media were replaced, the cells were able to restore their proliferating ability. The PANC-1 cells incubated in the bile-supplied media indicated that the mirovilli, mitochondria, and other organelles had thus been injured. These results suggest that bile acids appear to inhibit the proliferation of PANC-1 and MIA PaCa-2 cells, and the probable inhibitory mechanism is mainly considered to be due to the cytotoxicity of such bile acids.

Effects of dietary lipids on renal function of aged rats

Normal aging is accompanied by renal functional and morphological deterioration and dietetic manipulation has been used to delay this age-related decline. We examined the effects of chronic administration of diets containing 5% lipid-enriched diet (LD, w/w) on renal function of rats at different ages. Three types of LD were tested: canola oil, fish oil and butter. Mean systemic tail-cuff blood pressure and glycemia remained within the normal range whatever the age and the diet of the animals. Proteinuria began to rise from the 8th month in the groups ingesting LD, while in the control group it increased significantly (above 10 mg/24 h) only after the 10th month. With age, a significant and progressive decline in glomerular filtration rate (GFR) and renal plasma flow was observed in the LD groups but after 6 months of lipid supplementation, the decline in these parameters was more marked in the butter and fish oil groups. By the 18th month, the lowest GFR level was observed in the group ingesting the butter diet (2.93 +/- 0.22 vs 5.01 +/- 0.21 ml min(-1) kg(-1) in control, P<0.05). Net acid excretion, evaluated in 9- and 18-month-old rats, was stimulated in the fish oil group when compared both to control and to the other two LD groups. These results suggest that even low levels of LD in a chronic nutritional regimen can modify the age-related changes in renal function and that the impact of different types of lipid-supplemented diets on renal function depends on the kind of lipid present in the diet.

Portal vein thrombosis associated with hilar bile duct carcinoma and liver abscess

As most portal vein occlusion in hilar bile duct carcinoma is caused by tumor invasion to the portal vein, other mechanisms of its occlusion are very rare. We report the case of a 69-year-old man who underwent surgical resection for an advanced hilar bile duct carcinoma associated with unusual portal vein occlusion. Preoperative diagnosis was advanced hilar bile duct carcinoma with liver abscess and right portal vein occlusion due to tumor invasion. Extended right hepatectomy combined with resection of caudate lobe was performed. Intraoperatively, tumor invasion to the portal vein was not evident and resected margin of the right portal vein showed thrombosis and no evidence of malignancy histologically. To our knowledge, this is the first reported case of a patient with a combination of portal vein thrombosis and liver abscess in hilar bile duct carcinoma. Although portal vein occlusion due to thrombosis is an unusual complication in hilar bile duct carcinoma, the presence of liver abscess may be a useful diagnostic implication of this occlusion.

Cytokine response to human liver ischemia-reperfusion injury during hepatectomy: marker of injury or surgical stress?

BACKGROUND/AIMS

The aim of this study was to evaluate the inflammatory or antiinflammatory cytokine response to ischemia-reperfusion during hepatectomy and to find a useful marker of injury or surgical stress during hepatic ischemia-reperfusion.

METHODOLOGY

In 9 patients with liver disease who underwent hepatectomy using the Pringle maneuver, serum cytokines, including alanine transaminase, aspartate transaminase, and hyaluronic acid, were measured just prior to vascular occlusion; 5, 10 and 15 min after initial clamping; and 3 min after initial declamping.

RESULTS

The mean concentrations of aspartate transaminase and alanine transaminase did not significantly differ before and after ischemia-reperfusion during hepatectomy. However, mean concentrations of hyaluronic acid after ischemia-reperfusion were significantly (P < 0.03) higher than before clamping. Although there were no significant differences in the mean concentrations of IL-1 beta, IL-6, IL-8, IL-10 and TNF-alpha among, before and after ischemia-reperfusion, the mean concentrations of granulocyte colony-stimulating factor after ischemia-reperfusion and macrophage colony-stimulating factor after reperfusion were significantly (P < 0.05) higher than before clamping.

CONCLUSIONS

Although hepatic parenchymal cell function was maintained after ischemia-reperfusion during hepatectomy, sinusoidal endothelial cell dysfunction was found. Release of granulocyte colony-stimulating factor and macrophage colony-stimulating factor after ischemia-reperfusion were also found. These cytokines and hyaluronic acid may be useful indicators in the early phase of human ischemia-reperfusion injury during hepatectomy.

Very strong correlation between dominant negative activities of mutant thyroid hormone receptors and their binding avidity for corepressor SMRT

The syndrome of resistance to thyroid hormone (RTH) is an inherited disorder involving a mutation of the thyroid hormone receptor (TR) gene. Mutant (m) TR inhibits wild-type (wt) TR functions in a dominant negative manner, and this dominant negative effect (DNE) is a crucial factor in RTH pathogenesis. The molecular mechanism of the DNE is still unclear, although several possibilities (including competition between wt- and mTRs at the T(3) response element (TRE), sequestration of TR-associated protein(s) and titration out of functional TR) have been considered. Here we report that the DNE of mTRs is strongly correlated with their binding avidity for the retinoid X receptor (RXR), and especially for corepressor SMRT (silencing mediator for retinoid and thyroid hormone receptor), but not for the nuclear receptor corepressor, NCoR. The DNE of six natural TRs and four artificially constructed mTRs was assayed using a TR reporter gene containing TRE-DR4 (DR=direct repeat), TRE-pal (pal=palindrome) or TRE-lap (lap=inverted palindrome) in CV1 cells treated with 10 nM T(3). Of the mTRs examined, F451X (with a carboxy-terminal 11-amino-acid truncation) identified in a patient with RTH exhibited the strongest DNE on all TREs. The binding affinities between mTRs and corepressors SMRT or NCoR were quantified using a two-hybrid interference assay system consisting of VP16-TR(LBD) (LBD=ligand binding domain) and Gal4(DBD)-SMRT (DBD=DNA binding domain), or Gal4(DBD)-NCoR respectively, together with the Gal4 reporter gene. In this assay, VP16-TR(LBD) and Gal4(DBD)-SMRT (or Gal4 (DBD)-NCoR) interact with each other and trans-activate the Gal4 reporter gene. When an equal amount of mTR is coexpressed, it reduces the transcriptional activity of the reporter gene, depending on its binding avidity for a corepressor. A very strong correlation was observed between the SMRT-binding activity and the potency of the DNE among six natural mTRs and also among all mTRs, including four artificially constructed ones. The relationship between NCoR and DNE, however, was not significant. When we assayed the binding avidity of mTRs for RXR by using a two-hybrid assay system consisting of Gal4(DBD)-RXR(LBD) and VP16-TR(LBD), a significant correlation between DNE and binding avidity for the RXR was also observed. These results suggest that a corepressor plays an important role in DNE pathogenesis.

Differences between the silencing-related properties of the extreme carboxyl-terminal regions of thyroid hormone receptors alpha 1 and beta 1

Human thyroid hormone receptor (TR) is encoded by two distinct genes, TR alpha and TR beta. TR heterodimerizes with retinoid X receptor (RXR) and binds efficiently to the thyroid hormone (T(3)) response element (TRE) of target genes. In the absence of T(3), unliganded TR suppresses the basal promoter activity of positively regulated genes (silencing). Silencing mediator for retinoid and thyroid hormone receptors (SMRT) and nuclear receptor co-repressor (N-CoR) interact with unliganded TR and function as corepressor proteins. Previously, we found beta F451X with carboxyl (C)-terminal 11-amino acid deletion had stronger silencing potency than wild-type TR beta 1 and beta E449X with C-terminal 13-amino acid deletion on a subset of TREs. In the present study, to assess the isoform-specific effects of the C-terminal truncations on TR silencing, we constructed two mutant TR alpha 1s (alpha F397X and alpha E395X) with the same respective C-terminal truncations as beta F451X and beta E449X and analysed their silencing activities. Unlike beta F451X and beta E449X, alpha F397X and alpha E395X showed similarly stronger silencing potency than wild-type TR alpha 1. We further studied the abilities of wild-type and the mutant TR beta 1s and alpha 1s on RXR and co-repressor binding by a two-hybrid interference assay. beta F451X had significantly stronger abilities to bind to RXR and SMRT than did wild-type TR beta 1 and beta E449X. In contrast, wild-type TR alpha 1, alpha F397X and alpha E395X showed similar abilities to bind to RXR and SMRT. beta E449X and alpha E395X, which have identical C-terminal truncation, showed less ability to bind to N-CoR than did wild-type TR beta 1 and beta F451X and wild-type TR alpha 1 and alpha F397X respectively. These results indicate that an identical C-terminal truncation gives rise to different effects on TR beta 1 and alpha1 with respect to silencing potency, RXR binding and SMRT binding. The difference in the silencing potency among wild-type TR beta 1, beta F451X and beta E449X correlated well with the difference in the ability to bind co-repressor SMRT.

Compressibility and polygonization of single-walled carbon nanotubes under hydrostatic pressure

Single-walled carbon nanotubes show linear elasticity under hydrostatic pressure up to 1.5 GPa at room temperature. The volume compressibility, measured by in situ synchrotron x-ray diffraction, has been determined to be 0.024 GPa (-1). Theoretical calculations suggest that single-walled carbon nanotubes are polygonized when they form bundles of hexagonal close-packed structure and the intertubular gap is smaller than the equilibrium spacing of graphite (002) (d = 3.35 A). It has also been determined that the deformation of the trigonal nanotube lattice under hydrostatic pressure is reversible up to 4 GPa, beyond which the nanotube lattice is destroyed.

Giant cavernous hemangioma of the liver: is tumor size a risk factor for hepatectomy?

The aim of this study was to evaluate whether hepatic giant cavernous hemangioma (GCH) tumor size is a risk factor for hepatectomy. Twenty patients with GCH of the liver were treated by hepatic resection. Eleven patients with maximum resected specimen tumor size of >10 cm (mean tumor size, 18.5 cm; group 1) were compared with the 9 patients with tumor size. <10 cm (mean tumor size, 8.6 cm; group 2). The incidence of major hepatectomy in group 1 was significantly higher than that in group 2 (P = 0.0241). Although there were no significant differences in preoperative liver function, or in fibrinogen or platelet counts between the two groups, the level of preoperative fibrin degradation product (FDP) in group 1 was significantly higher than that in group 2 (P = 0.0116). Mean intraoperative hemorrhage volume, blood transfusion volume, and operation time in group 1 vs group 2 were 7003 ml vs 1092 ml (P = 0. 0251), 2927 ml vs 556 ml (P = 0.0169), and 431 min vs 216 min (P < 0. 0001), respectively. The incidence of postoperative complications in group 1 (45.5%) was higher than that in group 2 (22.2%), although not significantly so. There was no operative mortality in either group. Tumor size significantly correlated with intraoperative blood loss, operation time, weight of resected liver, intraoperative blood transfusion volume, and preoperative FDP levels. GCH tumor size is a significant risk factor for hepatectomy mainly because of the massive intraoperative blood loss and blood transfusion associated with major hepatic resection. More careful preoperative management to decrease tumor size may increase the safety of surgery for GCH of the liver.

Relationship between breast milk feeding and atopic dermatitis in children

OBJECTIVE

To determine whether or not the breast milk feeding has a role in the prevalence of atopic dermatitis among children.

METHODS

The target population of the study was all children participating in health check-up program for 3-year-old children in 60 municipalities locating 10 selected prefectures during designated 2 months between October and December 1997. Using a questionnaire, information on nutrition in infants (breast milk only, bottled milk only, or mixed), parity, mothers' age at birth, and a history of atopic dermatitis was obtained. Besides, data on potential confounding factors were obtained.

RESULTS

Questionnaires from 3856 children (81.6% of those who were to participate in the programs, and 96.4% of children who participated them) were analyzed. After the adjustment for all potential confounding factors using unconditional logistic models, the risk of atopic dermatitis was slightly higher among children with breast milk (odds ratio [OR] = 1.16 with 95% confidence interval [CI] 0.96-1.40). Mothers' age at birth (OR for those who were more than 30 years or older in comparison with those who were younger than 30 years = 1.15; 95% CI, 0.96-1.37) and those with second or later parity orders (OR = 1.14, 95% CI; 0.95-1.35) showed odds ratios that were higher than unity without statistical significance.

CONCLUSION

Breast milk elevates the risk of atopic dermatitis slightly without statistical significance; the risk may be, however, higher in children in second or later parity orders.

Colocalization of pinopsin with two types of G-protein alpha-subunits in the chicken pineal gland

Pinopsin is a photoreceptive molecule present in the outer segments of chicken pinealocytes. In this paper, the localization of alpha-subunits of G-proteins, rod transducin (Gt1) and Gq/11, was examined by immunoelectron microscopy to investigate whether these G-proteins colocalize with pinopsin in the outer segments. Ultrathin sections of the chicken pineal gland were double-immunolabeled with antibodies to pinopsin and either Gt1alpha or Gq/11alpha. As shown previously, the outer segments around the follicular lumen exhibited divergent morphology with ciliary, bulbous, or lamellate shapes, and most of them displayed pinopsin immunoreactivity. The majority (>90%) of pinopsin-immunopositive outer segments were labeled by anti-Gt1alpha and/or anti-Gq/11alpha antibodies. Application of double-immunolabeling to serial sections demonstrated that a large number of the pinopsin-immunopositive outer segments contained both Gt1alpha and Gq/11alpha immunoreactivities. These results suggest that Gt1alpha and Gq/11alpha are functionally coupled with light-activated pinopsin within a single outer segment.

Reresection for local recurrence of rectal cancer

Local recurrence is one of the major reasons that rectal cancer surgery is unsuccessful. The aim of this study was to investigate the surgical characteristics of patients undergoing reresection for local recurrence of rectal cancer. A total of nine patients were enrolled in this study, six of whom underwent total pelvic exenteration, one, posterior exenteration, one, abdominoperineal resection with sacral resection, and one, lymph node dissection alone. The mean operative time was 8 h 15 min, and the mean operative blood loss was 2 325 ml. Although major postoperative complications occurred in four patients (44%), there were no postoperative or hospital deaths. Lateral lymph node metastasis was detected in all four patients whose lateral lymph nodes were dissected or extirpated at the reresection. Two patients survived for more than 5 years without rerecurrence, and the cumulative 5-year survival rate was 26%. The para-aortic lymph nodes were the most common site of first rerecurrence. The results of this study indicate that patients who undergo reresection for local recurrence of rectal cancer are at high risk of devel-oping lateral or para-aortic nodal metastasis. Nevertheless, reresection may be a therapeutic option for the local recurrence of rectal cancer.

Hepatic resection of giant cavernous hemangioma of the liver

Surgical treatment of giant hemangioma of the liver is still controversial. The aim of this study is to examine the efficacy of hepatic resection for giant hemangioma of the liver. Twenty patients with giant cavernous hemangioma of the liver were treated by hepatic resection. The mean diameter of the hemangiomas was 13.9 cm (range, 6.5-30 cm). The surgical outcome was reviewed retrospectively. Major hepatectomy was performed in 14 patients and minor hepatectomy in 6 patients. Complications occurred in 7 of the 20 patients treated by hepatic resection. At a mean follow-up of 79 months (range, 12-173 months), 18 patients were symptom free whereas 2 patients had died--one died of pneumonia at 2 years and the other died of gastric cancer 6 years after surgery. Mean intraoperative hemorrhage and blood transfusion in all patients was 4,343 mL (range, 270-24,000 mL) and 1,860 mL (range, 0-8,800 mL) respectively. In the seven patients with preoperative high levels of fibrin degradation products (FDP), mean intraoperative hemorrhage and blood transfusion were markedly higher (9,371 mL and 3,714 mL respectively) than in the 13 patients without abnormal FDP (1,603 mL and 900 mL respectively). Preoperative hematologic status returned to normal after operation in all patients. Hepatic resection is a useful treatment for giant cavernous hemangioma of the liver. More careful management to reduce intraoperative hemorrhage is recommended to increase the safety of surgery, particularly in patients with preoperative abnormal FDP.

In vitro evaluation of antimicrotubule agents in human small-cell lung cancer cell lines

BACKGROUND

The improvement of treatment outcome of small-cell lung cancer (SCLC), and search for new effective drugs and to overcome drug-resistance are essential.

MATERIALS AND METHODS

We evaluated the cytotoxicity of antimicrotubule agents to seven human SCLC cell lines consisting of one cell line (SBC-3) established from a previously untreated patient as a representative of drug-sensitive cell line, three cell lines (SBC-2, SBC-4, and -7) derived from treated patients as representatives of intrinsic drug-resistance cell lines, and three drug-resistant sublines (SBC-3/ADM, SBC-3/ETP, and SBC-3/CDDP) selected by continuous exposure of the SBC-3 cell line to increasing concentrations of doxorubicin, etoposide, or cisplatin as representatives of acquired drug-resistant cell lines.

RESULTS

IC50 values for SBC-2, -3, -4, and -7 cells of antimicrotubule agents were markedly lower than those of doxorubicin, etoposide, and cisplatin. Both SBC-3/ADM and SBC-3/ETP subline were highly resistant to paclitaxel, docetaxel, vinorelbine, vincristine, vindesine, and vinblastine. However, an SBC-3/ADM subline was not fully cross-resistant to rhizoxin, and an SBC-3/ETP subline was as sensitive to rhizoxin as an SBC-3 cell line. A cisplatin-resistant subline, SBC-3/CDDP, showed no cross-resistance to the antimicrotubule agents.

CONCLUSION

These results suggest that antimicrotubule agents are useful for SCLC, and rhizoxin may be particularly effective in the salvage treatment of refractory or relapsed patients.

Establishment of a drug sensitivity panel using human lung cancer cell lines

We established a drug sensitivity panel consisting of 24 human lung cancer cell lines. Using this panel, we evaluated 26 anti-cancer agents: three alkylators, three platinum compounds, four antimetabolites, one topoisomerase I inhibitor, five topoisomerase II inhibitors, seven antimitotic agents and three tyrosine kinase inhibitors. This panel showed the following: a) Drug sensitivity patterns reflected their clinically-established patterns of action. For example, doxorubicin and etoposide were shown to be active against small cell lung cancer cell lines and mitomycin-C and 5-fluorouracil were active against non-small cell lung cancer cell lines, in agreement with clinical data. b) Correlation analysis of the mean graphs derived from the logarithm of IC50 values of the drugs gave insight into the mechanism of each drug's action. Thus, two drug combinations with reverse or no correlation, such as the combination of cisplatin and vinorelbine, might be good candidates for the ideal two drug combination in the treatment of lung cancer, as is being confirmed in clinical trials. c) Using cluster analysis of the cell lines in the panel with their drug sensitivity patterns, we could classify the cell lines into four groups depending on the drug sensitivity similarity. This classification will be useful to elucidate the cellular mechanism of action and drug resistance. Thus, our drug sensitivity panel will be helpful to explore new drugs or to develop a new combination of anti-cancer agents for the treatment of lung cancer.

Risk factors associated with intra-operative blood loss in hepatectomized patients with giant cavernous hemangioma of the liver

BACKGROUND/AIMS

The aim of this study was to clarify risk factors associated with intra-operative blood loss in hepatectomized patients with giant cavernous hemangioma (GCH) of the liver.

METHODOLOGY

Twenty patients with GCH of the liver were treated by hepatectomy. Eleven patients with intra-operative blood loss > 2000 ml (mean: 7145 +/- 7080 m; Group 1) were reviewed retrospectively and compared to 9 patients with intra-operative hemorrhage < 2000 ml (mean: 918 +/- 429 ml; Group 2).

RESULTS

Although there were no significant differences in pre-operative AST, ALT, and ICG-15 or fibrinogen and platelets between the two groups, pre-operative total bilirubin and fibrin degradation product (FDP) in Group 1 was significantly higher than in Group 2. Mean operation time and intra-operative blood transfusion in Group 1 versus Group 2 were 433 min vs. 213 min (p < 0.0001) and 3036 ml vs. 422 ml (p = 0.0072), respectively. The weight of resected liver (r = 0.821, p < 0.0001), maximum diameter of tumor (r = 0.782, p < 0.0001) and operation time (r = 0.748, p < 0.0001) were the most highly correlated with intra-operative blood loss, followed by pre-operative total bilirubin (r = 0.605, p = 0.0038), FDP level (r = 0.576, p = 0.0068) and intra-operative blood transfusion (r = 0.561, p = 0.0089).

CONCLUSIONS

These findings suggest that pre-operative management to reduce the tumor size, total bilirubin and FDP levels may be essential to minimize intra-operative hemorrhage and blood transfusion.

Effect of docetaxel with cisplatin or vinorelbine on lung cancer cell lines

Docetaxel shows substantial activity against lung cancer. To find the optimal drug combination for docetaxel, we evaluated the effects of cisplatin, etoposide, mitomycin C, irinotecan, vindesine, and vinorelbine using three human lung cancer cell lines, ABC-1, EBC-1, and SBC-3. Drug cytotoxicity was determined by MTT assay. Tumor cells were incubated for 96 hours in the presence of docetaxel and each of the test drugs stated above. The combined drug interaction was evaluated by median-effect plot analysis and improved IC50-isobologram analysis. Both methods showed strong antagonism (subadditive or protective effect) between docetaxel and etoposide when tested on ABC-1 and EBC-1 cells. Docetaxel and cisplatin displayed additive effects on all cell lines tested, when evaluated by improved IC50-isobologram analysis. The combination of docetaxel and vinorelbine exerted synergistic effect on the growth inhibition of SBC-3 cells, which showed a wide range of fractional cytotoxicity when analyzed by median-effect plot and supraadditive when analyzed by improved IC50-isobologram. These observations suggest a possibility that docetaxel can be used in combination with vinorelbine or cisplatin in the treatment of lung cancer.

Defective phototransductive disk membrane morphogenesis in transgenic mice expressing opsin with a mutated N-terminal domain

Retinitis pigmentosa is a heterogeneous group of inherited retinal disorders in which the photoreceptor cells degenerate. A line of transgenic mice expresses a mutant opsin gene that encodes three missense mutations near the amino terminus, including P23H, which is the basis for a common form of dominant retinitis pigmentosa. By studying the photoreceptor cells of these mice and their normal littermates, we found that: (1) opsin was routed correctly, (2) the concentration of opsin in the disk membranes appeared normal by freeze fracture analysis, (3) the amount of disk membrane shedding was normal, but (4) the basal disks of the outer segments were disorganized, indicating defective disk membrane morphogenesis. Defective disk membrane morphogenesis appears to result in the formation of fewer mature disks, thus accounting for observed gradual shortening of the photoreceptor outer segments with age. We suggest that abnormal disk membrane morphogenesis is the primary cellular defect that leads to blindness, and that it arises from the inability of nascent disk membranes, containing normal and mutant opsin, to interact normally with each other.

Actin-based vesicular transport in the first 20 min after dusk is crucial for daily rhabdom synthesis in the compound eye of the grapsid crab Hemigrapsus sanguineus

In the crab Hemigrapsus sanguineus, maintained under a 12 h:12 h light:dark cycle, the amount of vesicular smooth endoplasmic reticulum (vesicular sER) in the photoreceptor cell body increases after the light is turned off. This paper demonstrates that actin filaments in the photoreceptor cell body are involved in the transport of vesicular sER towards the rhabdom. To specify the time of actin contribution to rhabdom synthesis, we disrupted the organization of actin filaments in the cell body with cytochalasin D at various time around dusk. We then measured the rhabdom size and also examined the ultrastructure of the photoreceptor cell body 3 h after extinguishing the light. When cytochalasin D was applied from either 1 h before or immediately after extinguishing the light, the rhabdom size did not increase, whereas vesicular sER accumulated in the cell body. In contrast, cytochalasin D applied to the eyes from 20 min after turning the light off did not inhibit rhabdom synthesis. These results indicate that the first 20 min after the light is turned off is particularly important for the transport of vesicular sER towards the rhabdom by the cell body actin filaments.

[Chemotherapy for small-cell lung cancer]

Here we review the current treatments for small-cell lung cancer. Cisplatin and etoposide, combined with concurrent or alternating thoracic irradiation, have been considered to be the standard therapy for patients with limited disease. Dose-intensive weekly chemotherapy and high-dose chemotherapy with autologous stem cell transplantation have failed to increase survival in patients with extensive disease. Promising new drugs such as irinotecan and taxol may improve survival in patients with extensive disease.

A novel benzodiazepine inverse agonist, S-8510, as a cognitive enhancer

1. Pharmacological actions of a novel benzodiazepine receptor ligand, S-8510 (2-(3-isoxazolyl)-3,6,7,9-tetrahydroimidazo[4,5-d]pyrano+ ++[4,3-b] pyridine monophosphate monohydrate), were examined in in vitro and in vivo studies. 2. S-8510 was characterized as a partial inverse agonist with a modest GABA ratio and low efficacy. 3. S-8510 ameliorated memory impairment induced by cholinergic deficit in the water maze paradigm of Wistar rats. 4. S-8510 augmented LTP of the Schaffer collateral/commissural fiber-CA1 synapses in the hippocampal slice preparations of SD rat. 5. S-8510 increased the extracellular levels of acetylcholine and noradrenaline in the hippocampus of Wistar rat. 6. S-8510 selectively potentiated pentylenetetrazol-induced convulsion without affecting minimal electroconvulsive shock- or strychnine-induced convulsion in ddY mice. 7. S-8510 failed to induce any sign of anxiety in the Wistar rat pro-conflict test. 8. S-8510 showed antidepressant-like pharmacological actions in ddY mice. 9. These results suggest that S-8510 can be used as a therapeutic drug for senile dementia, including Alzheimer's disease with little risk for inducing anxiety or convulsion.