Prognostic significance of p53 and ras p21 expression in nonsmall cell lung cancer

BACKGROUND

Alterations of the p53 gene are one of the most common genetic changes in various types of cancer, including lung cancer. Abnormalities in the ras genes, including point mutations and overexpression, are another common feature in the molecular biology of lung cancer and are associated with a poorer prognosis. The authors' purpose was to determine expression of the mutated p53 gene in nonsmall cell lung cancer (NSCLC) specimens that were studied for expression of ras p21 and to document whether altered p53 expression was also an important factor for survival.

METHODS

Ninety-six patients with NSCLC underwent surgical resection between 1977 and 1985, 63 of whom received postoperative combination chemotherapy. None received radiation therapy. Tumor specimens were analyzed for altered p53 expression by immunohistochemistry. Univariate and multivariate analyses were performed to assess the association between p53 expression and survival.

RESULTS

Fifty-six (58%) of 96 tumor specimens showed altered p53 expression, and 91 patients were analyzed for survival. Altered p53 expression did not correlate with clinicopathologic characteristics except for postsurgical pathologic tumor (pT) classification. The patients with altered p53 expression survived for a significantly shorter period after surgery than those without p53 expression, including all patients who underwent resection and potentially curative resection (P = 0.02 and P = 0.048, respectively, generalized Wilcoxon test). Multivariate analysis showed independent prognostic significance for altered p53 expression (hazard ratio [HR] = 1.72, P = 0.04) and surgical cure (HR = 4.69, P < 0.001). The combined analysis of mutated p53 and ras p21 expression in the same tumor specimens revealed that patients with p53- and ras p21-negative tumors survived the longest among those with different p53 and ras p21 features (P = 0.005, generalized Wilcoxon test).

CONCLUSION

Altered p53 expression is a significant and independent negative prognostic factor for patients with surgically resected NSCLC: Combined immunohistochemical analysis of mutated p53 and ras p21 expression can divide patients with NSCLC into more accurate prognostic groups. If the current findings can be confirmed in larger prospective studies, combined immunohistochemical analysis of mutated p53 and ras p21 expression can be a useful clinical tool for stratifying patients with NSCLC into accurate prognostic groups and for identifying the population with a different risk of recurrence.

Mercury and methylmercury in fish and human hair from the Tapajós river basin, Brazil

Mercury is being released in the Amazon in an abusive way due to goldmining activities. The Tapajós river basin was the first to be intensively exploited in the modern Amazon gold rush. Fish and hair samples as the best indicators of human methylmercury contamination were investigated in the main cities and villages along the Tapajós river basin. The upper basin has typical fish fauna with much larger carnivorous fish with higher mercury levels reaching an average value of 0.69 microgram.g-1 wet wt. in 43 fish. This was accompanied by high levels in hair of the human population living in the same area. The maximum hair value reach 151 micrograms.g-1 dry wt. with two villages presenting an average value close to 25 micrograms.g-1 dry wt. An analytical laboratory intercalibration exercise was performed between Japanese and Brazilian laboratories for total mercury analysis. Critical fish, areas, and more exposed human groups are identified.

Differential expression of transforming growth factor-alpha and epidermal growth factor during postnatal development of rat submandibular gland

The concentration and the localization of transforming growth factor (TGF)-alpha and epidermal growth factor (EGF) in the submandibular glands (SMGs) of male Wistar rats of different ages (postnatal 0 to 10 weeks of age) were examined. Highest levels of TGF-alpha were seen early, at postnatal day 0; the levels dropped thereafter in an age-dependent manner, while EGF was not detectable before the third postnatal week. Immunoreactive localization of EGF was restricted to the granules of the granular convoluted tubule (GCT) cells in the mature SMGs, whereas TGF-alpha was observed throughout postnatal development over the entire duct system. TGF-alpha was demonstrated in the cytoplasm at early stages when the GCT granules were not observed and was also located on the granules at the late stage, as was the case for EGF, indicating that TGF-alpha is colocated with EGF in the mature SMG. These results demonstrate the differences between the expression of TGF-alpha and that of EGF in the developing rat SMG.

Repeated piezoelectric lithotripsy for gallstones with and without ursodeoxycholic acid dissolution: a multicenter study

The use of bile acid dissolution therapy in extracorporeal shockwave lithotripsy of gallstones, remains controversial. Our study examined whether chemolitholysis after sufficient disintegration enhanced stone clearance within 6 months of the first lithotripsy. A total of 143 patients who developed one to three radiolucent stones measuring < or = 30 mm in diameter were randomly separated into two treatment groups: 47% were given lithotripsy alone, and 53% lithotripsy plus ursodeoxycholic acid (UDCA). Repeated piezoelectric lithotripsy was given, with no limit on the total number of treatment sessions, to pulverize or disintegrate stones into fragments < 3 mm. Stones were disintegrated in 97% of all patients, and the fragments were < or = 2 mm in 50% of these patients. According to an intention-to-treat analysis, 52% in the lithotripsy alone group and 58% in the UDCA group were free of stones 6 months after the first lithotripsy (P = 0.61). Of the patients with fragments < or = 2 mm, 71% in the former and 86% in the latter group were free of stones 6 months after the first lithotripsy, with no significant difference between the groups. Biliary pain occurred in 25% of all patients, including 3 with acute cholecystitis. We concluded that the sufficient disintegration of gallstones achieved with repeated lithotripsy enhanced the early clearance of fragments, regardless of whether chemolitholysis was employed.

Desmosomal dissolution in Grover's disease, Hailey-Hailey's disease and Darier's disease

Proteins involved in the formation of desmosomes and simpler adherens junctions were studied in three types of non-immune acantholytic diseases; specifically, four cases of Grover's disease (GD), one case of Hailey-Hailey's disease (HHD) and one case of Darier's disease (DD), and these were compared to two cases of immune-mediated acantholytic disease pemphigus vulgaris (PV). The proteins studied included: 1. The intracellular desmosomal proteins, desmoplakin I and II and plakoglobin; 2. The intercellular desmosomal proteins, desmoglein and CD44; and 3. vinculin, which is a major intracellular protein of the simpler aherens junctions. In GD, HHD and DD, immunostaining showed a loss of desmoplakin I and II and plakoglobin from the desmosomes, and a diffuse staining in the cytoplasm. In contrast, in pemphigus vulgaris, these proteins seemed intact and were localized to dot-like spots on the cell surface. Also, desmoglein, and CD44 were slightly affected in GD, and moderately affected in HHD and DD. Absence of desmosomal attachment plaques, the lack of labeling with desmoglein in the affected desmosomes and a diffusion of the labels into cytoplasm were demonstrated with electron microscopy using an immunogold technique. In PV, desmoglein III is one of the target antigens for the autoantibodies in this disease and was only partially preserved in a small number of lesional cells, while CD44 was mostly preserved. Vinculin was intact in GD, HHD and DD, but was lost in PV. This study, our previous work, and that of others, suggest that: 1. In GD, HHD and DD, the proteins of the desmosomal attachment plaque are primarily affected; 2. In PV, the intercellular glycoproteins are primarily involved; and 3. Simple adherens junctions are intact in GD, HHD and DD, but are damaged in PV.

Specific antitumor activity of tumor-infiltrating lymphocytes expanded first in a culture with both anti-CD3 monoclonal antibody and activated B cells and then in a culture with interleukin-2

In order to expand tumor-infiltrating lymphocytes (TIL) efficiently and in order to use them for immunotherapy, we utilized lipopolysaccharide-activated B cells (LPS blasts) as costimulatory-signal-providing cells in an in vitro culture system. TIL, prepared from subcutaneously inoculated B16 melanoma, failed to expand when cultured with anti-CD3 monoclonal antibody (mAb) alone followed by a low dose of interleukin(IL)-2. In contrast, such TIL did expand efficiently in culture with both anti-CD3 mAb and LPS blasts followed by culture with IL-2. These findings suggest that the presence of LPS blasts in the initial culture was essential for the cell expansion. The expansion of TIL was partially blocked by the addition of CTLA4 Ig, which is an inhibitor of costimulatory molecules such as CD80 and CD86, and was almost blocked by the addition of anti-(Fc receptor gamma II)mAb. These findings thus indicate that such molecules, in conjunction with the receptor on the LPS blasts, participate in the efficient expansion of TIL. The B16-derived TIL, which expanded in our culture system, were predominantly CD8+ T cells and showed a higher level of cytolytic activity against B16 melanoma than either lymphokine-activated killer cells or TIL cultured with a high dose of IL-2. In addition, the in vitro expanded B16-derived TIL produced interferon gamma, but not IL-4, in response to B16 melanoma. What is more important, the adoptive transfer of such TIL had a significant antitumor effect against pulmonary metastasis in B16 melanoma, even without the concurrent administration of IL-2. Collectively, our results thus indicate the therapeutic efficacy of the protocol presented here for antitumor immunotherapy with TIL.

Gene regulation of brain natriuretic peptide in cardiocyte hypertrophy by alpha1-adrenergic stimulation

1. We previously demonstrated that brain natriuretic peptide (BNP) is a cardiac hormone mainly produced in the ventricle, while the major production site of atrial natriuretic peptide (ANP) is the atrium. The production and secretion of BNP and ANP in the hypertrophied ventricles were markedly augmented, serving as a compensation mechanism against ventricular overload by their natriuretic, diuretic and vasodilatory actions. 2. In the present study, we prepared an in vitro model of cardiocyte hypertrophy using cultured neonatal rat ventricular cardiocytes and alpha1-adrenergic stimulation, and examined the gene expressions of BNP and ANP during the process of cardiocyte hypertrophy. 3. The treatment of cultured ventricular cardiocytes with phenylephrine evoked cardiocyte hypertrophy around 24 h after the treatment, which was characterized by augmented expression of the myosin light chain-2 gene and increase in cell size. 4. In this model of cardiocyte hypertrophy, the steady-state level of BNP mRNA rapidly increased to the maximal level within 1 h after the treatment. In contrast, ANP mRNA began to increase at 3 h, and accumulated during the course of cardiocyte hypertrophy. The secretion of BNP from ventricular cardiocytes was also stimulated more rapidly than the ANP secretion. 5. These results indicate that the gene expression of BNP is distinctly regulated from that of ANP in cardiocyte hypertrophy, and suggest a discrete pathophysiological role of BNP as an 'emergency' cardiac hormone against ventricular overload.

Role of hepatocytes in direct clearance of lipopolysaccharide in rats

BACKGROUND & AIMS

The liver is the clearance organ for lipopolysaccharide (LPS). The aim of this study was to investigate the biliary excretion of LPS using fluorescein isothiocyanate (FITC)-labeled LPS.

METHODS

After FITC-LPS was injected intravenously into rats, the cellular localization of fluorescence in the liver was examined and the biliary excretion of fluorescence was measured. The effects of gadolinium chloride, a blocker of Kupffer cells, and colchicine, an inhibitor of microtubules, on the biliary excretion of fluorescence was investigated, and bile was analyzed using high-performance liquid chromatography.

RESULTS

Laser scanning confocal microscopy showed that fluorescence was taken up by hepatocytes 5 minutes after injection of FITC-LPS into the portal vein. When FITC-LPS was injected into the portal vein, fluorescence was rapidly secreted into bile, peaking at 20 minutes, and 25.1% of the injected dose appeared in bile within 60 minutes. When the same dose of FITC-LPS was injected into the tail vein, 15.8% appeared in bile within 60 minutes. Chromatography showed that FITC-LPS was excreted into bile in an unchanged form over a period of 20 minutes after injection. Colchicine significantly reduced the biliary excretion of fluorescence, but gadolinium chloride had no effect.

CONCLUSIONS

LPS was directly and effectively processed by hepatocytes and secreted into the bile canalicular system via a microtubule-dependent vesicular pathway.

[Gingival metastasis of large-cell lung cancer that produced G-CSF]

A 68-year-old man was referred to our hospital for further examination of a gingival mass. Chest radiographs and magnetic resonance imaging disclosed a bulky mass originating in the upper portion of the left lung, in contact with a chronic empyema lesion that first occurred after resection for pulmonary tuberculosis. Examination of a specimen obtained by percutaneous needle biopsy of the mass led to the diagnosis of large-cell carcinoma. Laboratory findings on admission showed marked leukocytosis (48,100/microliter) without evidence of severe a bacterial infection. The level of G-CSF in serum was abnormally high (246 pg/ml, normal value: < 30 pg/ml). Chemotherapy with vindesine, ifosfamide, and cisplatin resulted in shrinkage of the gingival mass, and a decrease in the G-CSF level to 66 pg/ml. Immunohistochemical staining with an anti-G-CSF monoclonal antibody to the primary lung tumor and the gingival mass obtained at autopsy was positive for cytoplasmic G-CSF.

Molecular cloning, characterization and expression of an elongation factor 1 alpha gene in maize

A cDNA (zmEF1A) and the corresponding genomic clone (zmgEF1A) of a member of the gene family encoding the alpha subunit of translation elongation factor 1 (EF-1 alpha) have been isolated from maize. The deduced amino acid sequence is 447 residues long interrupted by one intron. Southern blot analysis reveals that the cloned EF-1 alpha gene is one member out of a family consisting of at least six genes. As shown by northern hybridizations in leaves the mRNA level increases at low temperature whereas time-course experiments over 24 h at 5 degrees C show that in roots the overall mRNA level of EF-1 alpha is transiently decreased. These results indicate that the expression of EF-1 alpha is differently regulated in leaves and roots under cold stress.

Development of TCR-gamma delta CD4-CD8+ alpha alpha but not TCR-alpha beta CD4-CD8+ alpha alpha i-IEL is resistant to cyclosporin A

Present evidence suggests that cyclosporin A (CSA) inhibits the development of both alpha beta and gamma delta T cells in the thymus. However, whether CSA can inhibit the development of murine intestinal intraepithelial lymphocytes (i-IEL) is unknown as most i-IEL are clearly derived from a different lineage than the conventional thymus-derived T cells found in the periphery. Using the adult thymectomized, lethally irradiated bone-marrow reconstituted chimera (ATXBM mice) as a model for the development of extrathymically derived i-IEL and the fetal thymus-grafted (FTG) nude mice as a model for the development of thymically derived i-IEL, we demonstrate that CSA nearly completely inhibited the development of extrathymically, and possibly thymically, derived TCR-alpha beta i-IEL. Most of the TCR-alpha beta i-IEL whose development was inhibited by CSA belonged to the CD4-CD8+ alpha alpha subset. In contrast, the development of extrathymically and thymically derived TCR-gamma delta i-IEL was completely resistant to CSA. The phenotype of CSA-resistant TCR-gamma delta i-IEL in these models was not different from those in control mice, and the TCR-gamma delta i-IEL in CSA-treated mice appear to be mature and activated as most were large, granular, and CD69+. Lastly, we demonstrate that CSA does not affect the extrathymic positive selection of V delta 4 i-IEL in C3H hosts. These results suggest that despite their similarity, the intracellular activation cascade involved after TCR stimulation between TCR-alpha beta CD4-CD8+ alpha alpha and TCR-gamma delta CD4-CD8+ alpha alpha i-IEL are markedly different.

Development of TCR-gamma delta CD4-CD8+ alpha alpha but not TCR-alpha beta CD4-CD8+ alpha alpha i-IEL is resistant to cyclosporin A

Present evidence suggests that cyclosporin A (CSA) inhibits the development of both alpha beta and gamma delta T cells in the thymus. However, whether CSA can inhibit the development of murine intestinal intraepithelial lymphocytes (i-IEL) is unknown as most i-IEL are clearly derived from a different lineage than the conventional thymus-derived T cells found in the periphery. Using the adult thymectomized, lethally irradiated bone-marrow reconstituted chimera (ATXBM mice) as a model for the development of extrathymically derived i-IEL and the fetal thymus-grafted (FTG) nude mice as a model for the development of thymically derived i-IEL, we demonstrate that CSA nearly completely inhibited the development of extrathymically, and possibly thymically, derived TCR-alpha beta i-IEL. Most of the TCR-alpha beta i-IEL whose development was inhibited by CSA belonged to the CD4-CD8+ alpha alpha subset. In contrast, the development of extrathymically and thymically derived TCR-gamma delta i-IEL was completely resistant to CSA. The phenotype of CSA-resistant TCR-gamma delta i-IEL in these models was not different from those in control mice, and the TCR-gamma delta i-IEL in CSA-treated mice appear to be mature and activated as most were large, granular, and CD69+. Lastly, we demonstrate that CSA does not affect the extrathymic positive selection of V delta 4 i-IEL in C3H hosts. These results suggest that despite their similarity, the intracellular activation cascade involved after TCR stimulation between TCR-alpha beta CD4-CD8+ alpha alpha and TCR-gamma delta CD4-CD8+ alpha alpha i-IEL are markedly different.

[Induction chemotherapy followed by adjuvant surgery (IC-AS) in patients with stage I-II small cell lung cancer (SCLC)]

Ten patients with stage I-II SCLC received IC-AS between 1984 and 1993. As induction chemotherapy, COMP-VAN alternating chemotherapy and CAV-PVP hybrid chemotherapy were administered. The former consisted of a 4-drug combination of cyclophosphamide (CPA), vincristine (VCR), methotrexate (MTX) and procarbazine alternated with a 3-drug combination of etoposide (ETP), adriamycin (ADM) and nimustine every 4 weeks. In the latter, a 3-drug combination of CPA, ADM and VCR given on day 1, and a 2-drug combination of ETP and cisplatin on day 8, were repeated every 4 weeks. All the patients had an objective response, including one complete response by induction chemotherapy. Post-operative pathology revealed SCLC in 4 patients, adenocarcinoma in 2 and no tumor (pathological CR) in 4. Four patients relapsed, and a intrathoracic relapse was experienced in only 2 patients. Six patients have died: 3 from relapsing SCLC, 2 from stomach cancer, and 1 from squamous lung cancer, who was salvaged from relapsing SCLC. The median survival time was 27.5 months, and the 3-year survival rate 37.5%. These results indicate that IC-AS is highly effective for stage I-II SCLC and warrant additional studies comparing IC-AS with chemo-radiotherapy.

Concomitant immunity against tumor development is enhanced by the oral administration of a kampo medicine, Hochu-ekki-to (TJ-41: Bu-Zhong-Yi-Qi-Tang)

The oral administration of a kampo herbal medicine, Hochu-ekki-to (TJ-41: Bu-Zhong-Yi-Qi-Tang) using a water-supplying bottle resulted in a slight but significant inhibition of Meth A growth. The oral administration of TJ-41 with gastric gavage significantly enhanced the specific antitumor activity against Meth A at rechallenge on day 9. In a tumor-neutralizing assay, the tumor draining LN cells of the TJ-41 administered mice showed an antitumor activity against Meth A. In a cytolytic assay, the anti-Meth A specific cytolytic T lymphocyte activity was not detected in the spleen cells of the Meth A bearing and TJ-41 administered mice. The oral administration of TJ-41 enhanced the natural killer (NK) activity of the spleen cells in naive mice but could not improve the decreased NK activity of spleen cells from the tumor bearing mice. In a cytostatic assay, the peritoneal exudate cells from the Meth A bearing and TJ-41 administered mice showed a significantly higher amount of cytostatic activity against Meth A than that from either Meth A bearing or TJ-41 administered mice. These results indicate that the oral administration of TJ-41 into the tumor bearing mice may thus be able to enhance concomitant antitumor immunity through the augmentation of the cytostatic activity.

Transforming growth factor-alpha in human submandibular gland and saliva

A sensitive sandwich enzyme immunoassay (EIA) for transforming growth factor-alpha (TGF-alpha) utilizing a polyclonal antibody that recognizes limited epitopes of both human TGF-alpha and rat TGF-alpha in combination with a monoclonal anti-TGF-alpha IgG1 galactosidase conjugate was developed. This assay shows no cross-reactivity with human epidermal growth factor. We can quantify the TGF-alpha level in not only human TGF-alpha (detection limit: 1 pg/ml), but also rat TGF-alpha (detection limit: 10 pg/ml) by virtue of cross-reactivity. Employing this assay system, we demonstrated that TGF-alpha is present in both human submandibular glands and submandibular/sublingual saliva.

MR of childhood-onset dentatorubral-pallidoluysian atrophy

MR findings in a 14-year-old boy with progressive myoclonic epilepsy, who was diagnosed as having dentatorubral-pallidoluysian atrophy by DNA analysis, were compared with those of his father, who had adult-onset dentatorubral-pallidoluysian atrophy. Besides showing severe brain atrophy, especially of the brain stem tegmentum and cerebellum, MR showed diffuse periventricular hyperintensity on T2-weighted images. As compared with the proband, the father had a mild case.

[Evaluation by proton magnetic resonance spectroscopy of carotid-cavernous fistula with cortical venous drainage]

Cases with carotid-cavernous fistula (CCF) associated with cortical venous drainage through the sylvian veins are rather rare. However, such cases involve risk for subarachnoid hemorrhage, subcortical hemorrhage and venous infarction due to venous hypertension in the brain. Even without these symptoms, CCF under these conditions provokes disturbance in cerebral metabolism. We report two cases of CCF associated with cortical venous drainage evaluated by proton magnetic resonance spectroscopy (1H-MRS). Case 1: A 56 year-old female suffered from a right CCF associated with cortical venous drainage through the sylvian veins after trauma. Before embolization with a detachable balloon catheter, the ratios of N-acetyl-aspartate (NAA)/Choline (Cho) and NAA/Creatine (Cr) in 1H-MRS on the right temporo-basal ganglia were lower than those in normal volunteers. After curative balloon embolization of the CCF, serial 1H-MRS still demonstrated laterality (NAA/Cho and NAA/Cr ratios on the right side were lower than those on the left). Six months after embolization, these ratios on the right became closer to those on the left. Case 2: A 48 year-old female suffered from spontaneous CCF associated with cortical venous drainage. Before embolization of the CCF, ratios of NAA/Cho and NAA/Cr on the temporo-basal ganglia of the drainage side (left side) were lower than those on the contralateral side. After partial embolization of the CCF, which caused the angiographical disappearance of the cortical venous drainage, NAA/Cho and NAA/Cr ratios on the affected side increased to almost the same levels as those on the contralateral side. We consider that 1H-MRS is noninvasive and is a useful method to generate data evaluation of affected brain metabolism by venous reflux in cases of CCF associated with cortical venous drainage.

Reduced N-acetylaspartate in the brain observed on in vivo proton magnetic resonance spectroscopy in patients with mental retardation

Volume-selective proton magnetic resonance spectroscopy (1H-MRS) of the brain was performed with a 1.5T magnet in 28 patients with unclassified mental retardation (MR) and in 25 age-matched healthy children. Peaks of N-acetylaspartate (NAA), choline (Cho), and creatine (Cr), but not of lactate, were observed in both groups on 1H-MRS. In all our subjects of this age range, 1H-MRS revealed an increase with advancing age in the ratio of NAA/Cho (P = .0031), but no developmental change in the NAA/Cr and Cho/Cr ratios. The NAA/Cho ratio was lower in patients with MR than in controls (P = .0016). The NAA/Cr ratio tended to be lower in the MR group, and the Cho/Cr ratio did not differ between patients with MR and controls. These results suggest that in patients with MR, NAA decreases and a disorder and/or dysfunction of neurons in the brain exists.

A maize DNA-binding factor with a bZIP motif is induced by low temperature

We have isolated a low temperature-induced maize gene, mlip15, via cross hybridization using rice lip19. The longest cDNA isolated comprised 1179 bp and coded for a 135 amino acid bZIP (basic region/leucine zipper) protein. The gene showed 61.4% and 68.9% identity with the rice gene at the DNA and amino acid sequence levels, respectively, and is distinct from other maize genes that code for bZIP proteins. The level of mlip15 transcript was positively regulated by low temperature in the same way as the lip19 transcript. The levels of the transcript were also strongly increased by salt stress and exogenous abscisic acid, and slightly increased by anaerobiosis, but were not affected by heat shock and drought. The mLIP15 protein and truncated derivatives, produced in rabbit reticulocyte lysates or in an Escherichia coli expression system, were able to bind to a fragment of the wheat histone H3 gene promoter. This binding was diminished by addition of a molar excess of the hexamer sequence 5'-ACGTCA-3' found in the promoter and of the G-box-like sequence, but not by the addition of the ocs sequence or a mutated hexamer sequence. The factor bound to a promoter region of the maize Adh1 gene, expression of which is also induced by low temperature. These results lead to the conclusion that mlip15 is a strong candidate for a low temperature-induced transcription factor in maize.

Priming with donor spleen cells and activated B cells can induce prolonged survival of class I-disparate skin allografts in cyclophosphamide-treated mice

We have previously reported a method for inducing tolerance using cyclophosphamide (CP) in a murine model, in which 200 mg/kg of CP is administered intraperitoneally 2 days after intravenous priming with donor spleen cells. The CP-induced tolerance method, however, cannot induce long-lasting skin allograft survival in an MHC class I-disparate combination. In this study, we tried to explain this phenomenon based on a costimulatory theory. That is, allo-class I-reactive host CD8+ helper T cells may receive insufficient costimulatory signals from donor spleen cells and, therefore, they are resistant to subsequently administered CP. We demonstrated that activated donor B cells, which can deliver sufficient costimulatory signals, induce a more efficient proliferation of allo-class I-reactive host CD8+ helper T cells than naive B cells in vitro. In addition, we also demonstrated that our idea can also be applied to the CP-induced skin allograft tolerance in an MHC class I-disparate combination.

Quantitative analysis of AML1/ETO transcripts in peripheral blood stem cell harvests from patients with t(8;21) acute myelogenous leukaemia

Peripheral blood stem cells (PBSC) have been used increasingly for haemopoietic reconstitution after marrow-ablative chemotherapy in patients with acute leukaemia because of the possibility that there is a lower risk of leukaemic contamination. We have developed a titration assay using a competitive reverse transcriptase polymerase chain reaction (RT-PCR) which is able to estimate the number of AML1/ETO transcripts so that minimal residual disease (MRD) can be monitored quantitatively in patients with t(8;21) acute myelogenous leukaemia (AML). Using a qualitative RT-PCR method, AML1/ETO transcripts could be detected in all samples from 15 first PBSC harvests and 11 second PBSC harvests obtained from 15 patients with t(8;21) AML. With our competitive RT-PCR assay, the number of AML1/ETO transcripts was found to be lower in the second PBSC harvest than that in the first in every individual. Furthermore, MRD in PBSC harvests was less than that in the corresponding bone marrow obtained on the day of PBSC collection in the individual patients studied. In 10 patients who received autologous blood stem cell transplantation (ABSCT), we could not find a relationship between the number of AML1/ETO transcripts in the infused PBSC harvests and the clinical outcome after ABSCT. The present study clearly indicates that although PBSC harvests collected after consolidation chemotherapy are contaminated by leukaemic cells, the degree of leukaemic contamination may decrease as chemotherapy is repeated. The mobilization of PBSC by repeated chemotherapy may provide an advantageous source of haemopoietic stem cells for ABSCT.

Nizatidine accelerates gastric emptying of a solid meal in rats

Nizatidine, a new histamine-2-receptor antagonist, stimulates gastrointestinal motility in dogs and gastric emptying of liquids in rats. Effect of nizatidine on gastric emptying of a solid meal was investigated using a novel gastric emptying model in rats. Male Wistar rats (weighing 200-300 g) were supplied with powdered food containing 30 w/w% barium 14 hr before the beginning of the experiment and x-ray photography of rat stomach was taken under light ether anesthesia. Gastric emptying was assessed by percentage of a decrease in area 30 min after drug was injected intraperitoneally. There was a positive correlation between the area of the gastric outline and the weight of the gastric contents (r = 0.94, P < 0.01). Ether anesthesia itself did not affect gastric emptying. Nizatidine increased gastric emptying dose-dependently (emptied percentage; vehicle: 4.9 +/- 1.5%, 1 mg/kg: 7.2 +/- 0.4%, 3 mg/kg: 10.4 +/- 2.0%, 10 mg/kg: 16.7 +/- 4.9%, 30 mg/kg: 25.7 +/- 7.4%). N-Desmethyl nizatidine (NDM) also stimulated gastric emptying, but nizatidine S-oxide, cimetidine, an famotidine had no significant effects on gastric emptying. Nizatidine and neostigmine, but not NDM, at a subthreshold dose accelerated gastric emptying treated with a low dose of acetylcholine (0.1 mg/kg). Atropine (2 mg/kg, -30 min) did not modulate the gastroprokinetic action of nizatidine, but blocked that of NDM. These findings suggest that this noninvasive method may allow measurement of gastric emptying of solids accurately and that nizatidine and NDM facilitate gastric emptying probably mediated by a direct and/or an indirect (acetylcholinesterase inhibition) cholinergic mechanism.