Endoscopic mucosal resection for treatment of early gastric cancer

BACKGROUND

In Japan, endoscopic mucosal resection (EMR) is accepted as a treatment option for cases of early gastric cancer (EGC) where the probability of lymph node metastasis is low. The results of EMR for EGC at the National Cancer Center Hospital, Tokyo, over a 11 year period are presented.

METHODS

EMR was applied to patients with early cancers up to 30 mm in diameter that were of a well or moderately histologically differentiated type, and were superficially elevated and/or depressed (types I, IIa, and IIc) but without ulceration or definite signs of submucosal invasion. The resected specimens were carefully examined by serial sections at 2 mm intervals, and if histopathology revealed submucosal invasion and/or vessel involvement or if the resection margin was not clear, surgery was recommended.

RESULTS

Four hundred and seventy nine cancers in 445 patients were treated by EMR from 1987 to 1998 but submucosal invasion was found on subsequent pathological examination in 74 tumours. Sixty nine percent of intramucosal cancers (278/405) were resected with a clear margin. Of 127 cancers without "complete resection", 14 underwent an additional operation and nine were treated endoscopically; the remainder had intensive follow up. Local recurrence in the stomach occurred in 17 lesions followed conservatively, in one lesion treated endoscopically, and in five lesions with complete resection. All tumours were diagnosed by follow up endoscopy and subsequently treated by surgery. There were no gastric cancer related deaths during a median follow up period of 38 months (3-120 months). Bleeding and perforation (5%) were two major complications of EMR but there were no treatment related deaths.

CONCLUSION

In our experience, EMR allows us to perform less invasive treatment without sacrificing the possibility of cure.

Measurement of coronary sinus blood flow by continuous thermodilution in man

A technique was developed for measurement of blood flow in the coronary sinus in man by continuous thermodilution. For single determinations, 5% dextrose at room temperature is injected at a constant rate of 35 ml/min for a period of about 20 sec. In 14 subjects with normal coronary arteries the mean coronary sinus blood flow was 122 ± 25 ml/min (range, 83 to 159 ml/min). The blood flow computed per 100 g of left ventricle was 82 ± 16 ml/min, which is in the range of values obtained by nitrous oxide and coincidence counting methods. In 35 patients with arteriographically confirmed coronary artery disease the mean flow was similar (128 ± 20 ml/min; range, 92 to 167 ml/min).

A special catheter was used for simultaneous measurement of blood flow in the coronary sinus and great cardiac vein. In eight normal subjects the mean great cardiac vein flow was 68 ± 11 ml/min (range, 51 to 78 ml/min) or 65 ± 10% of the coronary sinus blood flow. The method allowed continuous measurement of flow over a period of several minutes and, for the first time, measurement of rapid changes in myocardial perfusion.

A low-operating-temperature solid oxide fuel cell in hydrocarbon-Air mixtures

The performance of a single-chamber solid oxide fuel cell was studied using a ceria-based solid electrolyte at temperatures below 773 kelvin. Electromotive forces of approximately 900 millivolts were generated from the cell in a flowing mixture of ethane or propane and air, where the solid electrolyte functioned as a purely ionic conductor. The electrode-reaction resistance was negligibly small in the total internal resistances of the cell. The resulting peak power density reached 403 and 101 milliwatts per square centimeter at 773 and 623 kelvin, respectively.

Three-dimensional multi-scale line filter for segmentation and visualization of curvilinear structures in medical images

This paper describes a method for the enhancement of curvilinear structures such as vessels and bronchi in three-dimensional (3-D) medical images. A 3-D line enhancement filter is developed with the aim of discriminating line structures from other structures and recovering line structures of various widths. The 3-D line filter is based on a combination of the eigenvalues of the 3-D Hessian matrix. Multi-scale integration is formulated by taking the maximum among single-scale filter responses, and its characteristics are examined to derive criteria for the selection of parameters in the formulation. The resultant multi-scale line-filtered images provide significantly improved segmentation and visualization of curvilinear structures. The usefulness of the method is demonstrated by the segmentation and visualization of brain vessels from magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA), bronchi from a chest CT, and liver vessels (portal veins) from an abdominal CT.

BRI1 is a critical component of a plasma-membrane receptor for plant steroids

Most multicellular organisms use steroids as signalling molecules for physiological and developmental regulation. Two different modes of steroid action have been described in animal systems: the well-studied gene regulation response mediated by nuclear receptors, and the rapid non-genomic responses mediated by proposed membrane-bound receptors. Plant genomes do not seem to encode members of the nuclear receptor superfamily. However, a transmembrane receptor kinase, brassinosteroid-insensitive1 (BRI1), has been implicated in brassinosteroid responses. Here we show that BRI1 functions as a receptor of brassinolide, the most active brassinosteroid. The number of brassinolide-binding sites and the degree of response to brassinolide depend on the level of BRI1 protein. The brassinolide-binding activity co-immunoprecipitates with BRI1, and requires a functional BRI1 extracellular domain. Moreover, treatment of Arabidopsis seedlings with brassinolide induces autophosphorylation of BRI1, which, together with our binding studies, shows that BRI1 is a receptor kinase that transduces steroid signals across the plasma membrane.

Involvement of interleukin-8, vascular endothelial growth factor, and basic fibroblast growth factor in tumor necrosis factor alpha-dependent angiogenesis

Tumor necrosis factor alpha (TNF-alpha) is a macrophage/monocyte-derived polypeptide which modulates the expression of various genes in vascular endothelial cells and induces angiogenesis. However, the underlying mechanism by which TNF-alpha mediates angiogenesis is not completely understood. In this study, we assessed whether TNF-alpha-induced angiogenesis is mediated through TNF-alpha itself or indirectly through other TNF-alpha-induced angiogenesis-promoting factors. Cellular mRNA levels of interleukin-8 (IL-8), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and their receptors were increased after the treatment of human microvascular endothelial cells with TNF-alpha (100 U/ml). TNF-alpha-dependent tubular morphogenesis in vascular endothelial cells was inhibited by the administration of anti-IL-8, anti-VEGF, and anti-bFGF antibodies, and coadministration of all three antibodies almost completely abrogated tubular formation. Moreover, treatment with Sp1, NF-kappaB, and c-Jun antisense oligonucleotides inhibited TNF-alpha-dependent tubular morphogenesis by microvascular endothelial cells. Administration of a NF-kappaB antisense oligonucleotide almost completely inhibited TNF-alpha-dependent IL-8 production and partially abrogated TNF-alpha-dependent VEGF production, and an Sp1 antisense sequence partially inhibited TNF-alpha-dependent production of VEGF. A c-Jun antisense oligonucleotide significantly inhibited TNF-alpha-dependent bFGF production but did not affect the production of IL-8 and VEGF. Administration of an anti-IL-8 or anti-VEGF antibody also blocked TNF-alpha-induced neovascularization in the rabbit cornea in vivo. Thus, angiogenesis by TNF-alpha appears to be modulated through various angiogenic factors, both in vitro and in vivo, and this pathway is controlled through paracrine and/or autocrine mechanisms.

Xanthine oxidase as a source of free radical damage in myocardial ischemia

Experiments were performed to determine if xanthine oxidase is a source of free radicals during myocardial ischemia. Open chest dogs were subjected to 1 h of total occlusion of the left anterior descending coronary artery followed by 4 h of reperfusion. Directly after coronary artery occlusion, Ce141 microspheres were injected into the left atrium to mark the ischemic bed. At the end of reperfusion, the hearts were removed and sectioned. Autoradiography determined the ischemic myocardium at risk, and the necrotic zone was determined by triphenyl-tetrazolium staining. Animals were divided into three groups: control, allopurinol (24-h oral pretreatment 400 mg, then 50 mg/kg IV bolus on occlusion); and superoxide dismutase starting with occlusion (15 000 U/kg). The size of the infarct as a percentage of the tissue at risk was: 23.1 +/- 4.1 for the control; 8.7 +/- 1.2 for the allopurinol group; and 5.4 +/- 1.2 for the superoxide dismutase group. The infarcts in the allopurinol and superoxide dismutase groups were significantly smaller than those in the control groups. In a second series of experiments we determined the xanthine oxidase/xanthine dehydrogenase content of dog myocardium. The left anterior descending branch was ligated for 30 min and then biopsies were removed from both the normal and the ischemic regions. Total enzyme content did not differ between the two regions averaging 0.259 U/g protein for the ischemic tissue and 0.225 U/g protein for the normal region. Only 9.8% of the enzyme was in the oxidase form in the normal region while 32.8% was in the oxidase form in the ischemic zone.(ABSTRACT TRUNCATED AT 250 WORDS)

Flat and depressed colonic neoplasms: a prospective study of 1000 colonoscopies in the UK

BACKGROUND

Flat and depressed colorectal tumours were originally thought to be unique to the Japanese population. Recently there have been reports of flat and depressed lesions in western countries but they have been thought to be uncommon.

METHODS

In this prospective study, 1000 consecutive patients attending for routine colonoscopy were examined for flat or depressed lesions. The examinations were done by one European colonoscopist using methods developed in Japan.

FINDINGS

321 adenomas were found: 202 (63%) were polypoid, 36% (117) were flat and 2 (0.6%) appeared depressed. Most adenomas contained areas of mild or moderate dysplasia but 10% (31) were severely dysplastic. Six Dukes' A adenocarcinomas were identified together with 25 more advanced adenocarcinomas. The likelihood of Dukes' A cancer or severe dysplasia increased from 4% (3/70) in small flat lesions, to 6% (9/154) in small polyps, 16% (8/50) in larger polyps, 29% (14/49) in large flat lesions, and 75% (3/4) in depressed lesions. 54% (20/37) lesions containing severe dysplasia or Dukes' A carcinoma were flat or depressed.

INTERPRETATION

The polyp-carcinoma hypothesis prompts colonoscopists to search only for polypoid lesions when screening for cancer, and many early colorectal neoplasms may therefore be missed. Colonoscopists require training in the recognition of flat and depressed lesions to detect colorectal tumours in the early stages.

Narrow-band imaging in the diagnosis of colorectal mucosal lesions: a pilot study

BACKGROUND AND STUDY AIMS

A newly developed narrow-band imaging (NBI) technique, in which modified optical filters were used in the light source of a video endoscope system, was applied during colonoscopy in a clinical setting. This pilot study evaluated the clinical feasibility of the NBI system for evaluating colorectal lesions.

PATIENTS AND METHODS

A total of 43 colorectal lesions in 34 patients were included in the study. The quality of visualization of colorectal lesions and the accuracy of differentiation between neoplastic and non-neoplastic lesions using the NBI system were evaluated in comparison with results from conventional colonoscopy and with chromoendoscopy.

RESULTS

For pit pattern delineation, NBI was superior to conventional endoscopy (P < 0.001), but inferior to chromoendoscopy (P < 0.05). NBI achieved better visualization of the mucosal vascular network and of the hue of lesions than conventional endoscopy (P < 0.05). However there was no significant difference between NBI and chromoendoscopy in differentiating neoplastic from non-neoplastic lesions (both techniques had a sensitivity of 100 % and a specificity 75 %). This was better than the results of conventional colonoscopy (sensitivity 83 %, specificity 44 %; P < 0.05 for specificity).

CONCLUSIONS

These results suggest that in the examination of colonic lesions the NBI system provides imaging features additional to those of both conventional endoscopy and chromoendoscopy. For distinguishing neoplasms from non-neoplastic lesions, NBI was equivalent to chromoendoscopy.

Combinatorial roles of olig2 and neurogenin2 in the coordinated induction of pan-neuronal and subtype-specific properties of motoneurons

Distinct classes of neurons are generated at defined times and positions during development of the nervous system. It remains elusive how specification of neuronal identity coordinates with acquisition of pan-neuronal properties. Here we show that basic helix-loop-helix (bHLH) transcription factors Olig2 and Neurogenin2 (Ngn2) play vital roles in the coordinated induction of pan-neuronal and subtype-specific properties of motoneurons. Olig2 and Ngn2 are specifically coexpressed in motoneuron progenitors. Misexpression studies in chick demonstrate the specific, combinatorial actions of Olig2 and Ngn2 in motoneuron generation. Our results further revealed crossregulatory interactions between bHLH and homeodomain transcription factors in the specification of motoneurons. We suggest that distinct classes of transcription factors collaborate to generate motoneurons in the ventral neural tube.

Induction of vascular endothelial growth factor by tumor necrosis factor alpha in human glioma cells. Possible roles of SP-1

The expression of vascular endothelial growth factor (VEGF) has been implicated in brain tumor angiogenesis, and the promoter region for the VEGF gene contains several SP-1 and AP-1 (c-Fos and c-Jun) binding motifs. Among eight human glioma cell lines, cellular mRNA levels of transcription factors SP-1 and AP-1 (c-Fos and c-Jun) were found to be closely correlated with those of VEGF. VEGF expression appears to be highly susceptible to hypoxia or exogenous cytokines and growth factors. Of various cytokines and growth factors, basic fibroblast growth factor (bFGF), tumor necrosis factor alpha (TNF-alpha), and interleukin 1 most potently enhanced VEGF mRNA levels of a glioma cell line, U251. Incubation of the glioma cells with bFGF or TNF-alpha increased both VEGF and SP-1 mRNA at 30 min and c-Fos mRNA at 1-3 h, over 5-fold. Nuclear run-on assays showed an apparent increase of the transcription of the VEGF gene as well as the SP-1 gene by bFGF or TNF-alpha. Gel mobility shift assays demonstrated that only SP-1 binding activity was increased 1 h after exposure to bFGF or TNF-alpha, and also that AP-1, but not SP-1, activity was significantly activated by hypoxia. Mithramycin, an inhibitor of SP-1, at 1-10 nM inhibited activation of the VEGF gene by bFGF or TNF-alpha but not that by hypoxia. Western blot analysis also demonstrated an increase in cellular amounts of VEGF by TNF-alpha and a decrease by co-administration with mithramycin. The promoter activity of the VEGF gene, which contains five SP-1 binding sites and one AP-1 binding site but not hypoxia regulatory elements, was enhanced by bFGF or TNF-alpha but not by hypoxia. The chloramphenicol acetyltransferase assay with VEGF promoter deletion constructs demonstrated that four clusterized SP-1 binding sites in the proximal promoter were essential for the basal transcription and the TNF-alpha-dependent activation. These data indicated that the expression of the VEGF gene enhanced by bFGF or TNF-alpha appeared to be mediated in part through the transcription factor SP-1, suggesting a different mechanism from that for hypoxia-induced activation of the VEGF gene.

Brassinosteroid-insensitive dwarf mutants of Arabidopsis accumulate brassinosteroids

Seven dwarf mutants resembling brassinosteroid (BR)-biosynthetic dwarfs were isolated that did not respond significantly to the application of exogenous BRs. Genetic and molecular analyses revealed that these were novel alleles of BRI1 (Brassinosteroid-Insensitive 1), which encodes a receptor kinase that may act as a receptor for BRs or be involved in downstream signaling. The results of morphological and molecular analyses indicated that these represent a range of alleles from weak to null. The endogenous BRs were examined from 5-week-old plants of a null allele (bri1-4) and two weak alleles (bri1-5 and bri1-6). Previous analysis of endogenous BRs in several BR-biosynthetic dwarf mutants revealed that active BRs are deficient in these mutants. However, bri1-4 plants accumulated very high levels of brassinolide, castasterone, and typhasterol (57-, 128-, and 33-fold higher, respectively, than those of wild-type plants). Weaker alleles (bri1-5 and bri1-6) also accumulated considerable levels of brassinolide, castasterone, and typhasterol, but less than the null allele (bri1-4). The levels of 6-deoxoBRs in bri1 mutants were comparable to that of wild type. The accumulation of biologically active BRs may result from the inability to utilize these active BRs, the inability to regulate BR biosynthesis in bri1 mutants, or both. Therefore, BRI1 is required for the homeostasis of endogenous BR levels.

Definitive chemoradiotherapy for T4 and/or M1 lymph node squamous cell carcinoma of the esophagus

PURPOSE

To investigate the efficacy and feasibility of concurrent chemoradiotherapy for locally advanced carcinoma of the esophagus.

PATIENTS AND METHODS

Fifty-four patients with clinically T4 and/or M1 lymph node (LYM) squamous cell carcinoma of the esophagus were enrolled. Patients received protracted infusion of fluorouracil 400 mg/m(2)/24 hours on days 1 to 5 and 8 to 12, 2-hour infusion of cisplatin 40 mg/m(2) on days 1 and 8, and concurrent radiation therapy at a dose of 30 Gy in 15 fractions over 3 weeks. Filgrastim was prophylactically administered to 35 patients. This schedule was repeated twice every 5 weeks, for a total radiation dose of 60 Gy, followed by two courses of fluorouracil (800 mg/m(2)/24 hours for 5 days) and cisplatin (80 mg/m(2) on day 1).

RESULTS

There were 21 patients with T4M0 disease, one with T2M1 LYM, 17 with T3M1 LYM, and 15 withT4M1 LYM. Forty-nine patients (91%) completed at least the chemoradiotherapy segment. The 18 patients (33%) who achieved a complete response included nine (25%) of the 36 with T4 disease and nine (50%) of the 18 with non-T4 disease. Major toxicities were leukocytopenia and esophagitis; there were four (7%) treatment-related deaths. Prophylactic filgrastim reduced the incidence of grade 3 or worse leukopenia without improving dose-intensity or response. With a median follow-up duration of 43 months, median survival time was 9 months. The 3-year survival rate was 23%.

CONCLUSION

Despite its significant toxicity, this combined modality seemed to have curative potential even in cases of locally advanced carcinoma of the esophagus.

Dynamic expression of basic helix-loop-helix Olig family members: implication of Olig2 in neuron and oligodendrocyte differentiation and identification of a new member, Olig3

Basic helix-loop-helix (bHLH) transcription factors have been shown to be essential for specification of various cell types. Here, we describe a novel bHLH family consisting of three members, two of which (Olig1, Olig2) are expressed in a nervous tissue-specific manner, whereas the third, Olig3 is found mainly in non-neural tissues. Olig1 and Olig2, which recently have been implicated in oligodendrogenesis, are expressed in the region of the ventral ventricular zone of late embryonic spinal cord where oligodendrocyte progenitors appear. In the embryonic brain, the Olig2 expression domain is broader than that of Olig1 and does not overlap with an oligodendrocyte progenitor marker, CNP. Furthermore, Olig2 is expressed in most cells in the ventral half of the early embryonic spinal cord, which do not yet express an early neuronal marker TuJ1. These results indicate that Olig2 expression is not limited to the oligodendrocyte lineage but includes immature neuronal progenitors and multipotential neuron/glia progenitors as well as embryonic olfactory neurons.

Characterization of a high molecular weight acidic nuclear protein recognized by autoantibodies in sera from patients with polymyositis-scleroderma overlap

Autoantibodies in the serum from a patient with connective tissue disease have been used to define a high molecule weight acidic nuclear protein antigen. The antigen tentatively termed Ku, after the first two letters of patient's name, has distinct physicochemical properties and immunological specificities that distinguish it from previously reported antigens. The Ku antigen has an apparent 300,000 mol wt as determined by gel filtration and sucrose density gradient ultracentrifugation techniques. The antigen is destroyed by trypsin, mild heating, and pH variations greater than 10 and less than 5. Treatment with ribonuclease or deoxyribonuclease did not affect the antigenic reactivity. The Ku antigen was demonstrated in the soluble extracts of human, calf, and rabbit, but not of rat tissues. Purified antibody localized the Ku antigen within the nuclei of human liver where a "reticular" pattern of immunofluorescence was seen. Of 330 patients with various connective tissue diseases, 9 had precipitating antibodies to the Ku antigen. Preliminary results of clinical analysis indicated that antibody to the Ku antigen might become a useful marker for a group of patients with clinical characteristics of both polymyositis and scleroderma with a good prognosis.

New endoscopic treatment for intramucosal gastric tumors using an insulated-tip diathermic knife

BACKGROUND AND STUDY AIMS

For one-piece resection the conventional technique of endoscopic mucosal resection (EMR) is limited to gastric mucosal tumors of 10 mm or less in size. In this retrospective study, we investigated the efficacy and complications associated with a new EMR method, using an insulated-tip diathermic knife (IT-EMR).

PATIENTS AND METHODS

In a total of 41 patients gastric mucosal tumors were resected using IT-EMR.

RESULTS

One-piece resection rates were 82% (14/17) for lesions of 10 mm or less, 75% (12/16) for those between 11 and 20 mm, and 14% (1/7) for those of over 20 mm. Complication rates for severe bleeding and perforation were 22% and 5%, respectively. With a median follow-up period of 32 months, no recurrence was observed after these procedures.

CONCLUSIONS

Compared with conventional EMR, this new method may have significant benefits, particularly regarding one-piece resection of lesions between 11 and 20 mm in size, and may also have a lower recurrence rate.

Contribution of visceral fat accumulation to the development of coronary artery disease in non-obese men

Associations between intra-abdominal visceral fat accumulations and coronary risk factors were studied in a sample of 29 non-obese men aged 57 +/- 10 years with coronary artery disease (CAD). Their body mass indexes (BMI) were 23.8 +/- 1.5 (range 18.7-26.3). The visceral fat area (VFA) and the subcutaneous fat area (SFA) were measured at the level of the umbilicus by computed tomography. In patients with CAD, the average VFA was significantly increased compared with that in 54 control subjects without CAD, matched for sex, age, and BMI (117.2 +/- 53.1 vs. 93.8 +/- 38.6 cm2, P < 0.05). However, their average SFA was not statistically different (111.2 +/- 33.3 vs. 106.3 +/- 35.7 cm2, N.S.). Eleven CAD patients (38%) and nine control subjects (17%) had greater than 2 S.D. higher than the mean VFA obtained from 22 healthy subjects extracted from the control subjects. Accordingly, the proportion of the subjects with high VFA was significantly higher in the CAD group. This group also had significantly higher levels of plasma glucose and insulin areas than controls determined by oral glucose tolerance tests. This may be due to insulin resistance. The proportion of the subjects with multiple risk factors including hyperlipidemia, hyperglycemia, and hypertension was significantly higher in the CAD patients with high VFA compared with the control subjects with normal VFA (CAD with high VFA 82% and control with normal VFA 33%). These findings suggest that visceral fat accumulations may play an important role in the occurrence of CAD regardless of obesity.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell heterogeneity upon myogenic differentiation: down-regulation of MyoD and Myf-5 generates ‘reserve cells’

When a proliferating myoblast culture is induced to differentiate by deprivation of serum in the medium, a significant proportion of cells escape from terminal differentiation, while the rest of the cells differentiate. Using C2C12 mouse myoblast cells, this heterogeneity observed upon differentiation was investigated with an emphasis on the myogenic regulatory factors. The differentiating part of the cell population followed a series of well-described events, including expression of myogenin, p21(WAF1), and contractile proteins, permanent withdrawal from the cell cycle and cell fusion, whereas the rest of the cells did not initiate any of these events. Interestingly, the latter cells showed an undetectable or greatly reduced level of MyoD and Myf-5 expression, which had been originally expressed in the undifferentiated proliferating myoblasts. When these undifferentiated cells were isolated and returned to the growth conditions, they progressed through the cell cycle and regained MyoD expression. These cells demonstrated identical features with the original culture on the deprivation of serum. They produced both MyoD-positive differentiating and MyoD-negative undifferentiated populations once again. Thus the undifferentiated cells in the serum-deprived culture were designated ‘reserve cells’. Upon serum deprivation, MyoD expression rapidly decreased as a result of down-regulation in approximately 50% of the cells. After this heterogenization, MyoD positive cells expressed myogenin, which is the earliest known event of terminal differentiation and marks irreversible commitment to this, while MyoD-negative cells did not differentiate and became the reserve cells. We also demonstrated that ectopic expression of MyoD converted the reserve cells to differentiating cells, indicating that down-regulation of MyoD is a causal event in the formation of reserve cells.

CD4+ T-lymphocytes and interleukin-5 mediate antigen-induced eosinophil infiltration into the mouse trachea

In order to determine the role of CD4+ and CD8+ T-cells and of interleukin-5 (IL-5) in causing antigen-induced eosinophil infiltration into the site of airway late-phase reaction, we examined the effect of the in vivo depletion of CD4+ and CD8+ T-cells on the eosinophil infiltration of the trachea induced by antigen inhalation in mice. We also studied the effect of anti-murine IL-5 monoclonal antibody (mAb) on the antigen-induced eosinophil infiltration in the trachea. The eosinophil infiltration into the trachea of ovalbumin (OVA)-sensitized BALB/c mice began to increase 9 h after OVA inhalation and persisted for more than 48 h. The in vivo depletion of CD4+ T-cells by pretreatment with anti-L3T4 mAb significantly decreased the eosinophil infiltration induced by OVA inhalation in the trachea of sensitized mice. However, the in vivo depletion of CD8+ T-cells by pretreatment with anti-Lyt-2 mAb had no significant effect on OVA-induced eosinophil infiltration in the trachea. Pretreatment with anti-murine IL-5 mAb also decreased OVA-induced eosinophil infiltration in the trachea. In contrast, neither disodium cromoglycate nor a selective antagonist for platelet-activating factor CV-6209 decreased OVA-induced airway eosinophilia in the mouse. Our results provide direct evidence that CD4+ but not CD8+ T-cells mediate antigen-induced eosinophil recruitment in the airways and that IL-5 mediates this eosinophil recruitment.

Characterization of brassinazole, a triazole-type brassinosteroid biosynthesis inhibitor

Screening for brassinosteroid (BR) biosynthesis inhibitors was performed to find chemicals that induce dwarfism in Arabidopsis, mutants that resembled BR biosynthesis mutants that can be rescued by BR. Through this screening experiment, the compound brassinazole was selected as the most potent chemical. In dark-grown Arabidopsis, brassinazole-induced morphological changes were nearly restored to those of wild type by treatment with brassinolide. The structure of brassinazole is similar to pacrobutrazol, a gibberellin biosynthesis inhibitor. However, in assays with cress (Lepidium sativum) plants, brassinazole-treated plants did not show recovery after the addition of gibberellin but showed good recovery after the addition of brassinolide. These data demonstrate that brassinazole is a specific BR biosynthesis inhibitor. Brassinazole-treated cress also showed dwarfism, with altered leaf morphology, including the downward curling and dark green color typical of Arabidopsis BR-deficient mutants, and this dwarfism was reversed by the application of 10 nM brassinolide. This result suggests that BRs are essential for plant growth, and that brassinazole can be used to clarify the function of BRs in plants as a complement to BR-deficient mutants. The brassinazole action site was also investigated by feeding BR biosynthesis intermediates to cress grown in the light.

Mice deficient for the IL-3/GM-CSF/IL-5 beta c receptor exhibit lung pathology and impaired immune response, while beta IL3 receptor-deficient mice are normal

The receptors for IL-3, GM-CSF, and IL-5 share a common beta subunit (beta c), and mice have an additional IL-3 beta subunit (beta IL3). We have independently generated mice carrying null mutations of each molecule. beta c mutant bone marrow showed no response to GM-CSF or IL-5, whereas IL-3 stimulation of beta c or beta IL3 mutant bone marrow was normal. beta c mutant mice showed lung pathology consisting of lymphocytic infiltration and areas resembling alveolar proteinosis, and also exhibited low basal numbers of eosinophils. Infection of beta c mutant mice by Nippostrongylus brasiliensis resulted in the absence of blood and lung eosinophilia. Animals repopulated with beta c mutant bone marrow cells showed slower leukocyte recovery and reduced eosinophil numbers. These data define the role of beta c in vivo, and show a phenotype that is likely to be the cumulative effect of loss of GM-CSF and IL-5 stimulation.

Effect of transient ischemia on free fatty acids and phospholipids in the gerbil brain. Lipid peroxidation as a possible cause of postischemic injury

The effect of transient bilateral carotid occulsion on levels of free fatty acids, phospholipids, and lipid peroxides in the brain was studied in gerbils. During occulsion, both saturated and polyunsaturated free fatty acids increased strikingly to approximately 11-fold in total by 30 minutes. During recirculation, however, a selectively rapid decrement occurred in arachidonic acid, while saturated fatty acids gradually decreased to their basal levels in 180 minutes. The peroxide level, estimated by a thiobarbituric acid test, did not change during occlusion, but was elevated on reperfusion. Phosphatidylethanolamine content decreased throughout the periods examined. These results do not support a hypothesis that lipid peroxidation is initated during ischemia by the lack of oxygen at the terminus of the mitochondrial respiratory chain. Instead, it is suggested that severe cerebral ischemia disintegrates membrane phospholipids, probably through activation of hydrolytic enzymes, and that overt peroxidative processes take place during reflow by means of restoration of oxygen supply. The peroxidative reactions may indeed, cause additional damage during the postischemic phase.