Brain segmentation and the generation of cortical surfaces

This paper describes methods for white matter segmentation in brain images and the generation of cortical surfaces from the segmentations. We have developed a system that allows a user to start with a brain volume, obtained by modalities such as MRI or cryosection, and constructs a complete digital representation of the cortical surface. The methodology consists of three basic components: local parametric modeling and Bayesian segmentation; surface generation and local quadratic coordinate fitting; and surface editing. Segmentations are computed by parametrically fitting known density functions to the histogram of the image using the expectation maximization algorithm [DLR77]. The parametric fits are obtained locally rather than globally over the whole volume to overcome local variations in gray levels. To represent the boundary of the gray and white matter we use triangulated meshes generated using isosurface generation algorithms [GH95]. A complete system of local parametric quadratic charts [JWM+95] is superimposed on the triangulated graph to facilitate smoothing and geodesic curve tracking. Algorithms for surface editing include extraction of the largest closed surface. Results for several macaque brains are presented comparing automated and hand surface generation.

Murine natural killer T(NKT) cells [correction of natural killer cells] contribute to the granulomatous reaction caused by mycobacterial cell walls

Mice injected with deproteinized cell walls prepared from the strain H37rv of Mycobacterium tuberculosis develop a granuloma-like lesion in which NKT cells are predominant. NKT cells play a primary role in the granulomatous response, because the latter does not occur in Jalpha281(-/-) mice, which miss NKT cells. The glycolipidic fraction of the cell walls is responsible for the recruitment of NKT cells; the recruiting activity is associated with fractions containing phosphatidylinositolmannosides. These results define a powerful experimental set up for studying the in vivo induction of NKT cell responses to microbial components.

Estimating AIDS incidence and jack-knife variance from a continuous delay distribution and incomplete data

Usual methods for estimating AIDS incidences are based on the inflation of a discrete reporting delay distribution, which often results in very imprecise estimates of the incidence in the most recent past. In this paper, we propose an alternative approach to estimate the AIDS incidence by inflating a continuous reporting delay distribution for each reported case. Covariate effects on reporting delays are evaluated by a proportional hazards model for the reverse time hazard function. A jack-knife variance for the estimated AIDS incidence is given. Study results showed that precision of estimates is improved by using the continuous time model as compared with those estimates given by its discrete counterpart. This feature is useful in assessing current trends in AIDS incidence.

Responses of sympathetic outflow to skin during caloric stimulation in humans

We previously showed that caloric vestibular stimulation elicits increases in sympathetic outflow to muscle (MSNA) in humans. The present study was conducted to determine the effect of this stimulation on sympathetic outflow to skin (SSNA). The SSNA in the tibial and peroneal nerves and nystagmus was recorded in nine subjects when the external meatus was irrigated with 50 ml of cold (10 degrees C) or warm (44 degrees C) water. During nystagmus, the SSNA in tibial and peroneal nerves decreased to 50 +/- 4% (with baseline value set as 100%) and 61 +/- 4%, respectively. The degree of SSNA suppression in both nerves was proportional to the maximum slow-phase velocity of nystagmus. After nystagmus, the SSNA increased to 166 +/- 7 and 168 +/- 6%, respectively, and the degree of motion sickness symptoms was correlated with this SSNA increase. These results suggest that the SSNA response differs from the MSNA response during caloric vestibular stimulation and that the SSNA response elicited in the initial period of caloric vestibular stimulation is different from that observed during the period of motion sickness symptoms.

Chromosomal clues to the development of prostate tumors

BACKGROUND

Cytogenetic, molecular cytogenetic, and molecular studies of prostate cancer have revealed an enormous amount of data regarding chromosomal loci that are aberrant in prostate tumors.

METHODS

These data have been compared and condensed in this review to determine which chromosomes and chromosome sites have been most frequently reported.

RESULTS

Loss of the Y chromosome, gain of 7, 8, and X, and interstitial deletions on 6q, 7q, 8p, 10q, 13q, 16q, 17q, and 18q are the most prevalent.

CONCLUSIONS

A potential model for genetic control of tumor progression is presented, as are data regarding the evaluation of a new series of tumors.

In vitro susceptibility of Helicobacter pylori to trifluoromethyl ketones

Heteroaromatic trifluoromethyl ketones (TFMK's) showed strong inhibitory activity against Helicobacter pylori. The MIC50 observed for 2-trifluoroacetonylbenzoxazole (1) is 20-fold more active than metronidazole and is only twice as high as that of clarithromycin. The inhibitory mode of TFMK's on Hp growth was not related to inhibition of urease.

The second BRCT domain of BRCA1 proteins interacts with p53 and stimulates transcription from the p21WAF1/CIP1 promoter

Inherited mutations in the breast and ovarian cancer susceptibility gene BRCA1 are associated with high risk for developing breast and ovarian cancers. Several studies link BRCA1 to transcriptional regulation, DNA repair, apoptosis and growth/tumor suppression. BRCA1 associates with p53 and stimulates transcription in both p53 dependent and p53-independent manners. BRCA1 splice variants BRCA1a (p110) and BRCA1b (p100) associates with CBP/p300 co-activators. Here we show that BRCA1a and BRCA1b proteins stimulate p53-dependent transcription from the p21WAF1/CIP1 promoter. In addition, the C-terminal second BRCA1 (BRCT) domain is sufficient for p53 mediated transactivation of the p21 promoter. Previous studies emphasized the importance of the BRCT domain, which shows homology with p53 binding protein (53BP1), in transcriptional activation, growth inhibition and tumor suppression. Our findings demonstrate an additional function for this domain in protein-protein interaction and co-activation of p53. We also found that BRCA1a and BRCA1b proteins interact with p53 in vitro and in vivo. The p53 interaction domain of BRCA1a/1b maps, in vitro, to the second BRCT domain (aa 1760-1863). The BRCT domain binds to the central domain of p53 which is required for sequence specific DNA binding. These results demonstrate for the first time the presence of a second p53 interaction domain in BRCA1 proteins and suggests that BRCA1a and BRCA1b proteins, like BRCA1, function as p53 co-activators. This BRCT domain also binds in vitro to CBP. These results suggest that one of the mechanisms by which BRCA1 proteins function is through recruitment of CBP/p300 associated HAT/FAT activity for acetylation of p53 to specific promoters resulting in transcriptional activation.

Attenuation of regional differentiation of sympathetic nerve activity during sleep in humans

The purpose of the present study was to clarify how the regional differentiation of sympathetic nerve activity (SNA) is modified during natural sleep in humans. In humans, muscle and skin sympathetic nerve activities (MSNA, SSNA) have been reported to discharge independently according to a regional differentiation of SNA during wakefulness. However, in natural sleep, MSNA and SSNA have been documented to synchronize during sleep stage 2 (Rechtschaffen and Kales). In the present study, we measured MSNA and SSNA simultaneously using a double recording technique of microneurography in eight healthy volunteers during natural sleep, and analyzed how MSNA and SSNA can be synchronized. We found that the synchronicity of MSNA and SSNA was accelerated in correlation with the deepening of the non-rapid eye movement (nonREM) sleep stages. We also documented that the burst properties of MSNA different from those of SSNA in wakefulness become similar to those of SSNA in the sleep stage, and MSNA synchronizes with SSNA. The synchronicity of MSNA and SSNA is presumably caused by a reduced effect of central inhibitory baroreflex pathways on MSNA during nonREM sleep. The present findings suggest that the regional differentiation of sympathetic nerve activity is attenuated with the deepening of nonREM sleep stages.

[Loss of heterozygosity and microsatellite instability in the region including BRCA1 of breast cancer in Chinese]

OBJECTIVE

To shed light on the relationship between BRCA1 gene and breast cancer in Chinese Han women.

METHODS

Four microsatellites DNA (D17S855, D17S579, D17S1327 and THRA1) within the BRCA1 gene were used as polymorphic markers. A study of loss of heterozygosity(LOH) and microsatellite instability(MSI) at the above- mentioned 4 microsatellites of 50 breast cancer patients was conducted by using PCR -PAUGE-DNA silver staining (polymerase chain reaction-polyacrylamide urea gel electrophoresis) method.

RESULTS

Twenty-nine or 58% of the informative cases showed LOH; 35.71%, 15. 38%, 18.18%, and 26.19% of the informative cases showed positive LOH at the D17S855, D17S579, D17S1327 and THRA1 loci respectively. The rate of MSI was 46%, and the rates of MSI at the four loci were 16%, 18%, 18% and 12% respectively. Further study on the associations between the phenomena of LOH and MSI and different clinical stages revealed that MSI was an early event in mammary tumorigenesis while LOH occurred at a later stage.

CONCLUSION

All of these suggest that breast cancer in Chinese be somehow linked to BRCA1.

Phosphorylcholine-coated metallic stents in rabbit iliac and porcine coronary arteries

The arterial wall reaction to phosphorylcholine-coated metal stents was examined in rabbits and pigs. Compared to non-coated stents, no significant difference was found by angiography and histology. We conclude that although phosphorylcholine-coating does not provoke arterial neointima formation or decrease luminal diameter compared to stainless steel stents, the coating does not seem to reduce restenosis.

The effect of bu shen sheng xue fang on beta-thalassemia at gene level

Isoelectrofocusing electrophoresis, PCR-SSCP analysis with DNA direct sequencing and RT-PCR were used to analyze the constituents of hemoglobin, determine the pattern of globin gene mutation, and detect its mRNA transcription extent. The results indicated that Bu Shen Sheng Xue Fang (BSSXF) significantly increased the contents of hemoglobin (Hb) and fetal hemoglobin (HbF), and the chain ratio in patients with beta-thalassemia. The drug is markedly effective in heterozygous, but not effective in homozygous or genetic compound patients. It was suggested that the beta-globin gene defects were compensated by elevating the gamma/beta + gamma ratio, promoting the transcription and expression of gamma-globin gene in synthesizing HbF.

Changes in muscle sympathetic nerve activity and effect of breathing maneuvers during microgravity induced by parabolic flight in humans

This study aimed to clarify how muscle sympathetic nerve activity (MSNA) in humans, which plays an important role in blood pressure control against gravity, is altered under microgravity (microG) conditions, and how the MSNA change is modified by breathing maneuvers. Ten subjects seated themselves in a jet aircraft with their knees extended. MSNA was recorded microneurographically from the left tibial nerve with simultaneous monitoring of ECG, blood pressure, respiration, and intrathoracic blood volume estimated by the impedance method during parabolic flight in a jet aircraft. In half of the parabolas, their respiration was controlled at 0.25 Hz by a metronome.

RESULTS

MSNA was enhanced under hypergravity just before microG entry, and immediately suppressed by microG induced by parabolic flight. The suppression was more marked with controlled than with uncontrolled respiration (51.6 +/- 7.2 vs 82.8 +/- 2.5%, mean +/- SE, 1G=100%). MSNA changes during microG correlated significantly to changes in blood pressure and intrathoracic blood volume. The blood pressure fall 10 to 15 sec after microG entry was less prominent with controlled than with uncontrolled respiration. We conclude that changes in arterial blood pressure and intrathoracic blood volume modulate MSNA during microG induced by parabolic flight, depending largely on breathing maneuvers.

Epidemiological, clinical and serological studies on trichinellosis in Henan Province, China

The epidemiological, clinical and serological studies on human trichinellosis in Henan Province were carried out from January 1992 to December 1996. The results showed that 467 patients attending our department came from 12 administrative areas and cities of the Province and they acquired the infection mainly by eating undercooked dumplings, tasting the raw pork filling for dumplings, ingesting scalded pork or mutton. There was the high incidence season of trichinellosis during the winter. Most of the patients were workers, officers and merchants aged 20-49 years, and the incidence was higher in males than in females. The main clinical manifestations of trichinellosis were fever, general myalgia, muscle tiredness and eosinophilia. Most of the patients had not any gastrointestinal symptoms and rash. Eyelid edema was only seen in the early courses of the disease. Eosinophil count increased with time, reached to the peak 3 weeks and decreased markedly 6 weeks after the onset of the disease. Eosinophil levels elevated obviously 1 week after therapy, began to drop rapidly 2 weeks after therapy, and decreased to a near normal levels 4 weeks after therapy. Anti-Trichinella antibodies were detected by IFAT using the frozen sections of the purified T. spiralis larvae as antigen. The specific antibodies were observed in only 70.2% of patients one week after onset of disease, and increased to 91, 94.3, and 100%; 2, 3, and 4 weeks, respectively after the onset. The antibody positive rate was evidently increased to 100% 1 week after therapy with abendazole, then decreased to 25% 4 months after therapy.

MR imaging in rat glioma model and gene therapy using EGFR antisence RNA

OBJECTIVE

To study the value of 1.5T MRI in long-term follow-up of rat C6 glioma model and the efficacy of EGFR antisence RNA therapy in vivo.

METHODS

Forty-three male Wistar rats, weighing 150 to 200 g, were used for this study. They were divided into four groups: group I (7 normal rats); group II (16 rats inoculated C6 cells in the right caudate nucleus); group III (12 rats with the C6 gliomas treated with EGFR antisence RNA by in site injection); and group IV (8 rats inoculated C6 cells transfected with EGFR antisence RNA in the right caudate nucleus). Group I was examined by plain and enhanced MR scanning. Group II-IV were followed up by plain and enhanced MR scanning and were sacrificed in variable time points for pathological examination.

RESULTS

Cerebral hemispheres of normal rat were shown clearly on the MR image. The tumor could be seen about 1 week after inoculation. According to the findings on the follow-up MR scan, we could observe growth of the tumor or its regression after treatment. The tumor growth was significantly inhibited in group III and group IV as compared to those in group II.

CONCLUSION

The growth of the rat C6 glioma model and its change after treatment could be shown clearly in 1.5T MR imaging; EGFR antisence RNA significantly inhibited the growth of glioma in vivo.

Chromosome 7 abnormalities in prostate cancer detected by dual-color fluorescence in situ hybridization

Aneusomy of chromosome 7 and loss at 7q (especially 7q31.1) have been reported in prostate cancer. To further investigate abnormalities of 7q and the relationship with whole chromosome 7 changes, we have conducted a dual-color fluorescence in situ hybridization (FISH) analysis on isolated nuclei from 28 primary prostate cancers. A pericentromeric probe for chromosome 7, five newly isolated sequence-specific bacterial artificial chromosome (BAC) probes from 7q31.1, and one BAC for the epidermal growth factor receptor (EGFR) gene at 7p12 were used in dual color hybridizations. Pericentromeric probes for chromosomes X and 4 were also used as controls. Sixteen (57.1%) of the 28 tumors showed clonal aberrations. Nine of them were trisomy 7 and four were hypertetrasomy for chromosome 7. Deletions at 7q31.1 were found in two of the high grade tumors. With the exception of these two cases, all other cases showed concordant results using all probes. These findings confirm previous studies that aneusomy of 7 is associated with prostate cancer progression, and there may be a tumor suppressor gene (TSG) at 7q31.1 which is associated with tumor progression. In addition, our study indicates: (1) the deletion pattern of individual nuclei infers that deletions at 7q31.1 precede reduplications of chromosome 7; and (2) the amplification of EGFR was not detected at the DNA level, suggesting that activation of this oncogene may play a minor role in prostate cancer.

Hypoglycemic effect of water-soluble polysaccharide from Auricularia auricula-judae Quel. on genetically diabetic KK-Ay mice

The hypoglycemic effect of water-soluble polysaccharide(FA) from fruiting bodies of Auricularia auricula-judae Quel. was investigated on genetically diabetic mice (KK-Ay) from 10 to 14 weeks of age. Male mice were divided into 3 groups, the control group and FA-fed group having free access to the control diet or FA diet (30 g of FA/kg of diet). The food-restricted group had restricted access to the control diet at the level of the diet consumed by the FA-fed group. Compared with the control group, FA supplementation had a significant effect in lowering plasma glucose, insulin, urinary glucose, and food intake. FA administration also increased the tolerance to intraperitoneal glucose loading and the hepatic glycogen content. In the food-restricted group, the reduced food intake slightly lowered the plasma and urinary glucose levels, but did not improve hyperinsulinemia and glucose tolerance. This study shows that FA had a hypoglycemic effect on KK-Ay mice, and the reduced food consumption was not a major factor which contributed to the hypoglycemic action of FA.

Sympathetic nerve response to muscle during anteroposterior acceleration in humans

This study aimed to elucidate the effects of linear acceleration on muscle sympathetic nerve activity (MSNA) in humans. Eight healthy young male volunteers were seated in a linear accelerator (sled) during the recording of their electrocardiogram, blood pressure with the Finapres, thoracic impedance and respiration curve. MSNA was recorded from the tibial nerve by microneurography. At a fixed distance of sled movements in an anteroposterior direction, eight modes of stimulation with peak accelerations at 0.05, 0.10, 0.15, and 0.20 G (gravity) in sinusoidal or step mode were applied to each subject. Each movement was repeated for 5 cycles. Both the total activity and the burst rate of MSNA decreased during acceleration, and the level of the decrease was proportional to the level of the acceleration, whereas the average heart rate, thoracic impedance and mean arterial pressure did not change significantly. These results suggests that moderate linear acceleration may suppress MSNA in humans.

[Time resolved photoluminescence of PPV derivatives/C60 combination system]

We report the integrated and picosecond time-resolved photoluminescence (TRPL) measurement from two kinds of combination films: Poly(2-methoxy-5-(4-butenyloxy)phenylene vinylene) (MB-PPV)/C60 and Poly (2-methoxy-5-(4'-bromo-butoxy) phenylene vinylene) (MBB-PPV)/C60. Comparing with the pure MBB-PPV film, PL weakening and quenching of MBB-PPV were observed in the multilayer and mixed MBB-PPV/C60 films respectively. From TRPL spectra, the change of PL decay lifetime could be clearly seen, those could be attributed to the excitation transfer (ET) process between the excited MBB-PPV molecule and C60 molecule. Further measurements indicate that there is no noticeable dependence of the ET process on the temperature in the combination films.

An outbreak of paragonimiosis in Zhengzhou city, China

An outbreak of paragonimiosis occurred in the city of Zhengzhou, Central China, in May 1995. Of seven exposed urban inhabitants, four were seropositive for Paragonimus and had clinical symptoms consistent with acute paragonimiosis. All of four cases treated were cured with praziquantel. The P. skrjabini adult worm was obtained from the rats experimentally infected with the crabs collected in the mountainous area where the urban inhabitants had got the infection. The outbreak was attributed to the intake of raw freshwater crabs while on tourist trips in a mountainous area.

The structure and function of murine factor V and its inactivation by protein C

Factor V (FV) is a central regulator of hemostasis, serving both as a critical cofactor for the prothrombinase activity of factor Xa and the target for proteolytic inactivation by the anticoagulant, activated protein C (APC). To examine the evolutionary conservation of FV procoagulant activity and functional inactivation by APC, we cloned and sequenced the coding region of murine FV cDNA and generated recombinant wild-type and mutant murine FV proteins. The murine FV cDNA encodes a 2,183-amino acid protein. Sequence comparison shows that the A1-A3 and C1-C2 domains of FV are highly conserved, demonstrating greater than 84% sequence identity between murine and human, and 60% overall amino acid identity among human, bovine, and murine FV sequences. In contrast, only 35% identity among all three species is observed for the poorly conserved B domain. The arginines at all thrombin cleavage sites and the R305 and R504 APC cleavage sites (corresponding to amino acid residues R306 and R506 in human FV) are invariant in all three species. Point mutants were generated to substitute glutamine at R305, R504, or both (R305/R504). Wild-type and all three mutant FV recombinant proteins show equivalent FV procoagulant activity. Single mutations at R305 or R504 result in partial resistance of FV to APC inactivation, whereas recombinant murine FV carrying both mutations (R305Q/R504Q) is nearly completely APC resistant. Thus, the structure and function of FV and its interaction with APC are highly conserved across mammalian species.

Changing pattern of delays in reporting AIDS diagnoses in Australia

To accurately monitor and predict the progress of the HIV/AIDS epidemic, it is important to adjust reported AIDS counts for reporting delays. This requires estimation of the reporting delay distribution. This paper aims to use a statistical model to identify the main factors influencing reporting delays in Australia and to adjust reported incidence data for these delays among cases of AIDS diagnosed from 1993 and reported before 30 June 1997. Reporting delays were found to vary significantly across states/territories. The influence of calendar time of diagnosis was also significant, with an overall trend toward longer delays over time. AIDS cases diagnosed in the fourth quarter of a year were reported significantly more quickly than those diagnosed in the first or third quarters. No significant differences were found due to sex, age and HIV exposure category, except people with haemophilia, in whom AIDS cases appeared to be reported more slowly. After adjusting for under-reporting and reporting delay, we found that the AIDS incidence in Australia was declining from about 1000 cases per year in 1994 to about 760 cases per year in 1996.

Natural killer-like nonspecific tumor cell lysis mediated by specific ligand-activated Valpha14 NKT cells

We have recently identified alpha-galactosylceramide (alpha-GalCer) as a specific ligand for an invariant Valpha14/Vbeta8.2 T cell receptor exclusively expressed on the majority of Valpha14 NKT cells, a novel subset of lymphocytes. Here, we report that alpha-GalCer selectively activates Valpha14 NKT cells resulting in prevention of tumor metastasis. The effector mechanisms of the ligand-activated Valpha14 NKT cells seem to be mediated by natural killer (NK)-like nonspecific cytotoxicity. Indeed, the cytotoxic index obtained by alpha-GalCer-activated Valpha14 NKT cells was reduced by the addition of cold target tumor cells or by treatment with concanamycin A, which inhibits activation and secretion of perforin, but not by mAbs against molecules involved in the NKT cell recognition and conventional cytotoxicity, such as CD1d, Vbeta8, NK1. 1, Ly49C, Fas, or Fas ligand. These results suggest that the ligand-activated Valpha14 NKT cells kill tumor cells directly through a CD1d/Valpha14 T cell receptor-independent, NK-like mechanism.

[Development of emission models for volatile organic compounds from indoor materials]

Volatile organic compounds (VOCs) emitted from indoor materials was a major cause of indoor air pollution. The characteristics of VOCs emission was an important part of research programs on indoor air quality. The technology of test chambers with exactly controllable conditions has been successfully used in studies of VOCs emissions. The technology could be used to model the chamber VOCs concentration level vs time profile C(t), which could in turn be used to estimate the sample emission rate vs time profile R(t). The emission models of VOCs from indoor materials were presented in this review. The principal of emission process, parameters and the applications of emission models were introduced. The application of diffusion model, dilution model and vapor pressure (VP) model were limited due to the existence of sink effect. Sink model is the most promising model at present.

The role of ras gene mutation in gastric cancer and precancerous lesions

Abnormality of ras gene family was studied in a total of 206 cases of gastric cancer and precancerous lesions by PCR-RFLP, PCR-SSCP and DNA sequencing. The results showed that mutation rate of H-ras 12 codon in metaplasia, atypical hyperplasia, early-stage cancer and advanced cancer was 16.7%, 31.2%, 50.0%, and 32.2%, respectively. In the groups of superficial gastritis and normal controls, no mutation were detected in codon 12 of ras. Mutations of H-ras 61 codon and N-ras 12 codon in various groups were the same as those in normal control. K-ras 12 codon mutation was detected in only 2 cases of gastric cancer by using PCR-SSCP, but it was not detected by DNA sequencing, which may be polymorphism. All H-ras 12 codon mutations were G-->T mutation. There were significant difference between the groups of metaplasia, dysplasia, gastric carcinoma and normal control group (P < 0.05, P < 0.01, P < 0.01, respectively). It was concluded that H-ras 12 codon mutation was an early event and may play an important role in gastric carcinogenesis. Although K-ras, N-ras mutation rates are high in colon cancer and leukemia, it seems to bear no relationship with gastric cancer.

[LH-CG receptor protein expression in epithelial ovarian cancer]

OBJECTIVE

To evaluate the relationship between (LH-CG) receptor expression and prognosis in epithelial ovarian cancer.

METHODS

The relative quantity of LH-CG receptor protein of epithelial ovarian cancer tissuse was detected with semiquantitative western immunobloting in 40 cases. The LH-CG receptor protein was located with immunohistochemistry. The LH-CG receptor was termed high expression if its concentration was more than and/or equal to the median, and low expression if its concentration was less than the median. 36 of the 40 cases were followed up at various intervals, the longest follow up period was 56 months. There were 16 cases with high LH-CG expression and 20 cases with low LH-CG receptor expression in which 9 cases died.

RESULTS

The positive rate of LH-CG receptor protein expression was 72.5% (29/40). The level of LH-CG receptor protein expression in patients with stages I and II was higher than that in patients with stages III and IV, but it is not significant (P > 0.05). The LH-CG receptor concentration in the well-differentiated cancer group was twice as much as that in the poorly-differentiated cancer group. The difference between the well-differentiated group and the poorly-differentiated group was significant (P < 0.05). The 1-year and 3-year survival rates were 83.94% and 67.15% respectively in the high LH-CG receptor expression group. Both of the 1-year and 3-year survival rates were 33. 34% in the low LH-CG receptor expression group. The survival rates of the high expression group was significantly higher than those of the low expression group (P < 0.05). LH-CG receptor expression did not correlate with age, lymph node metastases, the size of residual tumor and CA125.

CONCLUSION

The prognosis of patients with high LH-CG receptor expression is better than that of those with low expression.

Sympathetic nerve response to microgravity induced by parabolic flight

The aim of this study was to clarify how muscle sympathetic nerve activity (MSNA) in humans, which plays an important role in blood pressure control against gravity, is altered under microgravity conditions. Subjects were seated in a jet aircraft with their legs extended. MSNA was recorded microneurographically from the tibial nerve of the sitting subjects with simultaneous monitoring of electrocardiogram, blood pressure, respiration, and intrathoracic blood volume during parabolic flights. In the Air Force training area, the aircraft made parabolas up to 10 times. At the entry to microgravity, intrathoracic blood volume increased, systemic blood pressure was elevated, and MSNA was suppressed. However, this MSNA suppression lasted only 10-15 sec, and then followed by an enhancement to the end of the parabolas. We conclude that MSNA is suppressed at the onset of microgravity during parabolic flight in response to loading of the cardiopulmonary volume receptor due to a cephalad body fluid shift. However, this MSNA suppression is transient during such dynamic gravitational changes as those induced by parabolic flight, probably modulated by arterial baroreceptors.

[A novel immune system]

We found a novel lymphoid cell lineage, V alpha 14 NKT cell, which is characterized by 1) the expression of both NK1.1 (NK receptor) and an invariant TCR encoded by V alpha 14 and J alpha 281 gene segments; 2) the expression of unusual phenotypes, such as NK1.1+, B220+, Mac-1+, HSA+, CD44+, CD45Rlow and MEL-14low; and 3) the extrathymic development: V alpha 14 NKT cells appear at d9.5 of gestation before thymus development. Moreover, the deletion of the invariant V alpha 14 TCR gene expression caused the lack of NKT cells in vivo, while transgene of the invariant V alpha 14 V beta 8 TCR in the RAG-deficient background resulted in the generation of only V alpha 14 NKT cells without other lymphoid cells. These results indicate the essential requirement of invariant V alpha 14 TCR for the development of NKT cells. Recent studies clearly show that V alpha 14 NKT cells, but not NK cells or T cells are the primary target of IL-12 in the IL-12-mediated tumor rejection.

CD1d-restricted and TCR-mediated activation of valpha14 NKT cells by glycosylceramides

Natural killer T (NKT) lymphocytes express an invariant T cell antigen receptor (TCR) encoded by the Valpha14 and Jalpha281 gene segments. A glycosylceramide-containing alpha-anomeric sugar with a longer fatty acyl chain (C26) and sphingosine base (C18) was identified as a ligand for this TCR. Glycosylceramide-mediated proliferative responses of Valpha14 NKT cells were abrogated by treatment with chloroquine-concanamycin A or by monoclonal antibodies against CD1d/Vbeta8, CD40/CD40L, or B7/CTLA-4/CD28, but not by interference with the function of a transporter-associated protein. Thus, this lymphocyte shares distinct recognition systems with either T or NK cells.

Requirement for Valpha14 NKT cells in IL-12-mediated rejection of tumors

A lymphocyte subpopulation, the Valpha14 natural killer T (NKT) cells, expresses both NK1.1 and a single invariant T cell receptor encoded by the Valpha14 and Jalpha281 gene segments. Mice with a deletion of the Jalpha281 gene segment were found to exclusively lack this subpopulation. The Valpha14 NKT cell-deficient mice could no longer mediate the interleukin-12 (IL-12)-induced rejection of tumors. Although the antitumor effect of IL-12 was thought to be mediated through natural killer cells and T cells, Valpha14 NKT cells were found to be an essential target of IL-12, and they mediated their cytotoxicity by an NK-like effector mechanism after activation with IL-12.

Inhibition of platelet deposition with local delivery of heparin using a double balloon catheter

Heparin is an effective agent in the treatment of unstable angina and myocardial infarction. The clinical utility of heparin is limited by bleeding complications. This study was performed to determine whether static delivery of heparin could effectively inhibit further platelet deposition. Thrombogenic graft segments were incorporated into chronic arteriovenous shunts in pigs. Autologous platelets were labeled with 111Indium. Platelet deposition was quantitated with gamma camera imaging. The grafts were exposed to blood flow for 15 min in order to induce platelet deposition on the thrombogenic surface. Heparin was delivered locally either by direct exposure or with a double balloon catheter. After a 15 minute exposure period, the heparin solution was removed and subsequent platelet deposition was monitored for 90 minutes. Heparin, administered with the double balloon catheter in doses as low as 12.5 U, effectively inhibited further platelet deposition. An intravenous injection of 100 U of heparin, the highest dose use for local delivery, did not perturb bleeding time or the activated partial thromboplastin time. In conclusion, platelet deposition can be inhibited with static local delivery of heparin at doses that are not associated with systemic bleeding.

Response to vestibular stimulation of sympathetic outflow to muscle in humans

The objective of the present study was to determine the effect of vestibular stimulation on the sympathetic outflow to muscle in humans. Fourteen healthy volunteers were studied while in the supine position with electrocardiography, blood pressure monitoring and electro-oculography. The muscle sympathetic nerve activity (MSNA) was recorded directly from the bilateral tibial nerves by using microneurographic double recording technique. Caloric vestibular stimulation was loaded by alternate irrigation with 50 ml of cold (10 degrees C) water and 50 ml of hot (44 degrees C) water into the left and right external meatus. After cold water irrigation, two MSNA response peaks were elicited, respectively, before and after the maximum slow phase velocity (SPV) of nystagmus. The first peak of the MSNA enhancement was caused by non-specific factors because its time course coincided with that in cold pressor test with immersion of the subject's hand in ice/water (4 degrees C). Transient suppression of MSNA after cold water irrigation in the period of maximum SPV of nystagmus was observed by cross correlogram analysis between the SPV of the nystagmus and MSNA. After hot water irrigation, only one MSNA response peak was elicited after the period of strong nystagmus. The second peak of MSNA enhancement evoked by cold irrigation (379.4 +/- 221.8%, with the control value set as 100%, mean +/- SE) was significantly higher than that evoked by hot irrigation (243.0 +/- 14.5%). The degree of MSNA enhancement by either cold (the second peak) or hot stimulation was proportional to the maximum SPV of the nystagmus. There was no significant difference between the MSNA responses ipsilateral to and contralateral to the irrigated side. In conclusion, the caloric vestibular stimulation can influence the bilateral sympathetic outflow to muscle in humans. The degree of MSNA enhancement is proportional to the magnitude of vestibular excitement indicated by maximum slow phase velocity of the nystagmus.

[Phenylethanoid glucosides from flos Buddlejae]

Four phenylethanoid glucosides were isolated from the flower of Buddleja officinalis. On the basis of specteral data, they were identified as salidroside(1), verbascoside(2), isoverbascoside(3) and echinacoside(4). Compounds 1, 3 and 4 were obtained from the plant for the first time. Compound 2 showed antibacterial and anticancer activities.

Allosteric gating of a large conductance Ca-activated K+ channel

Large-conductance Ca-activated potassium channels (BK channels) are uniquely sensitive to both membrane potential and intracellular Ca2+. Recent work has demonstrated that in the gating of these channels there are voltage-sensitive steps that are separate from Ca2+ binding steps. Based on this result and the macroscopic steady state and kinetic properties of the cloned BK channel mslo, we have recently proposed a general kinetic scheme to describe the interaction between voltage and Ca2+ in the gating of the mslo channel (Cui, J., D.H. Cox, and R.W. Aldrich. 1997. J. Gen. Physiol. In press.). This scheme supposes that the channel exists in two main conformations, closed and open. The conformational change between closed and open is voltage dependent. Ca2+ binds to both the closed and open conformations, but on average binds more tightly to the open conformation and thereby promotes channel opening. Here we describe the basic properties of models of this form and test their ability to mimic mslo macroscopic steady state and kinetic behavior. The simplest form of this scheme corresponds to a voltage-dependent version of the Monod-Wyman-Changeux (MWC) model of allosteric proteins. The success of voltage-dependent MWC models in describing many aspects of mslo gating suggests that these channels may share a common molecular mechanism with other allosteric proteins whose behaviors have been modeled using the MWC formalism. We also demonstrate how this scheme can arise as a simplification of a more complex scheme that is based on the premise that the channel is a homotetramer with a single Ca2+ binding site and a single voltage sensor in each subunit. Aspects of the mslo data not well fitted by the simplified scheme will likely be better accounted for by this more general scheme. The kinetic schemes discussed in this paper may be useful in interpreting the effects of BK channel modifications or mutations.

Histopathological and electron microscopical studies on experimental Penicillium marneffei infection in mice

Experimental Penicillium marneffei infection in mice was investigated histopathologically and by electron microscopy. Viable conidia (5 x 10(6) cells) of P. marneffei were inoculated into each mouse of group A (BALB/c mice) and group B (BALB/c-nu/nu-SIc mice) through the tail vein. All the mice were sacrificed at intervals and the livers were examined. In group A, the conidia were phagocytosed by Kupffer cells soon after inoculation, and proliferated by fission in the cytoplasm. Marked proliferation of yeast cells was observed 7 and 14 days after inoculation. With proliferation of the fungus, the number of lysosomes in Kupffer cells increased, and numerous granulomas were formed in the liver. These granulomas consisted mainly of macrophages with yeast cells, together with a few polymorphonuclear leukocytes, lymphocytes and giant cells. From 28 days on yeast cells were gradually cleared from the granulomas, and 56 days after inoculation almost all the granulomas disappeared. In group B, at an early stage of infection, similar pathological changes to those seen in mice of group A were observed. However, as the infection progressed, the number of granulomas continued to increase and yeast cells continued to proliferate although lymphocytes did not infiltrate these granulomas. With proliferation of yeast cells the liver tissue was replaced with both yeast cells engulfed by macrophages and extracellular yeasts, and dissemination occurred.

BRCA1 proteins are transported to the nucleus in the absence of serum and splice variants BRCA1a, BRCA1b are tyrosine phosphoproteins that associate with E2F, cyclins and cyclin dependent kinases

BRCA1, a familial breast and ovarian cancer susceptibility gene encodes nuclear phosphoproteins that function as tumor suppressors in human breast cancer cells. Previously, we have shown that overexpression of a BRCA1 splice variant BRCA1a accelerates apoptosis in human breast cancer cells. In an attempt to determine whether the subcellular localization of BRCA1 is cell cycle regulated, we have studied the subcellular distribution of BRCA1 in asynchronous and growth arrested normal, breast and ovarian cancer cells using different BRCA1 antibodies by immunofluorescence and immunohistochemical staining. Upon serum starvation of NIH3T3, some breast and ovarian cancer cells, most of the BRCA1 protein redistributed to the nucleus revealing a new type of regulation that may modulate the activity of BRCA1 gene. We have also characterized two new variant BRCA1 proteins (BRCA1a/p110 and BRCA1b/ p100) which are phosphoproteins containing phosphotyrosine. Immunofluorescence and Western blotting analysis indicate cytoplasmic and nuclear localization of BRCA1a and BRCA1b proteins. To elucidate the biological function of BRCA1, we created a bacterial fusion protein of glutathione-transferase (GST) and BRCA1 zinc finger domain and detected two cellular proteins with molecular weights of approximately 32 and 65 kD, one of which contains phosphotyrosine designated p32 and p65 BRCA1 interacting proteins (BIP) that specifically interact with BRCA1. Western blot analysis of BIP with cyclins/CDKs and E2F antisera indicated association with cdc2, cdk2, cdk4, cyclin B, cyclin D, cyclin A and E2F-4 but not with cdk3, cdk5, cdk6, E2F-1, E2F-2, E2F-3, E2F-5 and cyclin E. Furthermore, we have also demonstrated a direct interaction of in vitro translated BRCA1a and BRCA1b proteins with recombinant cyclin A, cyclin B1, cyclin D1, cdc2, cdk2 and E2F fusion proteins in vitro. Taken together these results seem to suggest that BRCA1 could be an important negative regulator of cell cycle that functions through interaction with E2F transcriptional factors and phosphorylation by cyclins/cdk complexes with the zinc ring finger functioning as a major protein-protein interaction domain. If the interactions we observe in vitro is also seen in vivo then it may be possible that lack or impaired binding of the disrupted BRCA1 proteins to E2F, cyclins/CDKs in patients with mutations in the zinc finger domain could deprive the cell of an important mechanism for braking cell proliferation leading to the development of breast and ovarian cancers.

Epidemiological and clinical studies on an outbreak of trichinosis in central China

An outbreak of trichinosis occurred in the city of Zhengzhou, central China, between December 1995 and February 1996, affecting 85 of the administrative units into which the city is split. Of 297 subjects from eight of the affected units, 54% were seropositive for Trichinella and 41% had symptoms consistent with acute trichinosis. Of the 490 subjects who had eaten at one particular dumpling restaurant 1-5 weeks before the outbreak and who were traced, 291 (59%) were seropositive and 212 (43%) had been or were ill. MOst of the infections were in manual workers, cadres and merchants aged 20-49 years. Most of those who had been infected failed to develop gastro-intestinal symptoms or a cutaneous rash. Eyelid oedema was only seen in the early stages of the infection, the main clinical manifestations being fever of long duration of tiredness. Surprisingly, six cases had no marked symptoms after repeated infection. Eosinophilia (eosinophils > 7% of leucocytes) was noted in 71 (55%) of the 130 cases in which blood cells were counted. When 212 sera were tested for antibodies to Trichinella, seropositivities were found to increase from 89.1% (IFAT) of 87.7% (microprecipitation test) at presentation to 100% (both tests) 1 week after treatment with albendazole. All those treated were cured. The outbreak was one of the most extensive, single-source outbreaks ever recorded in China, probably with > 600 infections and > 300 clinical cases. The entire episode was attributed to the ingestion of undercooked pork dumplings at one restaurant.

[Using lyophilization to the preparation of drug paper disks for antimicrobial susceptibility test]

It was found that the paper disks used in the antimicrobial susceptibility test could be prepared by natural drying at 37 degrees C, but the drug distribution between these disks is not so enen as determined by antimicrobial inhibitory test, thus it was difficult to fit the needs of the national standards. Alternatively, we applied the lyophilization technique to the disks preparation and 12 batches, of different antibiotic disks were made out and found that the difference between disks is reduced, and all are meet to the national requirement. It is supposed that the capillary action may play a role in the variation of drug distribution in the natural drying process, and the lyophilization process avoided the capillary action, hence the more even distributed antibiotic disks are produced. The preparation of lyophilized disks is a simple and practical method that could be used in the antimicrobial susceptibility tests in hospital.

Intrinsic voltage dependence and Ca2+ regulation of mslo large conductance Ca-activated K+ channels

The kinetic and steady-state properties of macroscopic mslo Ca-activated K+ currents were studied in excised patches from Xenopus oocytes. In response to voltage steps, the timecourse of both activation and deactivation, but for a brief delay in activation, could be approximated by a single exponential function over a wide range of voltages and internal Ca2+ concentrations ([Ca]i). Activation rates increased with voltage and with [Ca]i, and approached saturation at high [Ca]i. Deactivation rates generally decreased with [Ca]i and voltage, and approached saturation at high [Ca]i. Plots of the macroscopic conductance as a function of voltage (G-V) and the time constant of activation and deactivation shifted leftward along the voltage axis with increasing [Ca]i. G-V relations could be approximated by a Boltzmann function with an equivalent gating charge which ranged between 1.1 and 1.8 e as [Ca]i varied between 0.84 and 1,000 microM. Hill analysis indicates that at least three Ca2+ binding sites can contribute to channel activation. Three lines of evidence indicate that there is at least one voltage-dependent unimolecular conformational change associated with mslo gating that is separate from Ca2+ binding. (a) The position of the mslo G-V relation does not vary logarithmically with [Ca]i. (b) The macroscopic rate constant of activation approaches saturation at high [Ca]i but remains voltage dependent. (c) With strong depolarizations mslo currents can be nearly maximally activated without binding Ca2+. These results can be understood in terms of a channel which must undergo a central voltage-dependent rate limiting conformational change in order to move from closed to open, with rapid Ca2+ binding to both open and closed states modulating this central step.

Separation of gating properties from permeation and block in mslo large conductance Ca-activated K+ channels

In this and the following paper we have examined the kinetic and steady-state properties of macroscopic mslo Ca-activated K+ currents in order to interpret these currents in terms of the gating behavior of the mslo channel. To do so, however, it was necessary to first find conditions by which we could separate the effects that changes in Ca2+ concentration or membrane voltage have on channel permeation from the effects these stimuli have on channel gating. In this study we investigate three phenomena which are unrelated to gating but are manifest in macroscopic current records: a saturation of single channel current at high voltage, a rapid voltage-dependent Ca2+ block, and a slow voltage-dependent Ba2+ block. Where possible methods are described by which these phenomena can be separated from the effects that changes in Ca2+ concentration and membrane voltage have on channel gating. Where this is not possible, some assessment of the impact these effects have on gating parameters determined from macroscopic current measurements is provided. We have also found that without considering the effects of Ca2+ and voltage on channel permeation and block, macroscopic current measurements suggest that mslo channels do not reach the same maximum open probability at all Ca2+ concentrations. Taking into account permeation and blocking effects, however, we find that this is not the case. The maximum open probability of the mslo channel is the same or very similar over a Ca2+ concentration range spanning three orders of magnitude indicating that over this range the internal Ca2+ concentration does not limit the ability of the channel to be activated by voltage.

Phenotypes and invariant alpha beta TCR expression of peripheral V alpha 14+ NK T cells

A novel subset of peripheral T cells, peripheral NK T cells, is found to be a major population comprising 5% of splenic T and 40% of bone marrow T cells. The majority of peripheral NK T cells are characterized by the expression of an invariant TCR-alpha encoded by V alpha 14/J alpha 281 with a one nucleotide N region. Moreover, a specific reduction of V alpha 14+ NK T cells has been demonstrated to be tightly associated with various autoimmune diseases, indicating their decisive role in autoimmune disease development. In this study, we investigated the phenotypes of peripheral V alpha 14+ NK T cells and their TCR-beta repertoire. Peripheral V alpha 14+ NK T cells, comprise two populations, i.e., small and large sized cells, at an equal frequency, belonged to the CD4- CD8- fraction, and are heat stable antigen(bright), macrophage-1bright, B220bright, CD45RBdim, and Mel-14dim, but CD5-, distinct from thymic NK T cells. TCR-beta analysis clearly showed that peripheral V alpha 14+ NK T cells utilized two to three dominant invariant TCR-beta, such as V beta 8.2 D beta J beta 2.5/V beta 7 D beta J beta 2.1 in the spleen and liver, V beta 8.2 D beta J beta 2.5/V beta 8.3 D beta J beta 2.2/V beta 7 D beta J beta 2.6 in the bone marrow, and V beta 7 D beta J beta 2.1/V beta 3 D beta J beta 1.2 in intestinal intraepithelial lymphocytes. Judging from the unusual surface phenotypes, such as heat stable antigen, macrophage-1, B220, CD45RBdim, and Mel-14dim, which are known to be T cell activation markers, peripheral V alpha 14+ NK T cells may always be activated under physiologic conditions, resulting in the oligoclonal expansion of V alpha 14+ NK T cells with different invariant TCR-beta in different peripheral organs. The unique features of V alpha 14+ NK T cells are discussed.

Phenotypes and invariant alpha beta TCR expression of peripheral V alpha 14+ NK T cells

A novel subset of peripheral T cells, peripheral NK T cells, is found to be a major population comprising 5% of splenic T and 40% of bone marrow T cells. The majority of peripheral NK T cells are characterized by the expression of an invariant TCR-alpha encoded by V alpha 14/J alpha 281 with a one nucleotide N region. Moreover, a specific reduction of V alpha 14+ NK T cells has been demonstrated to be tightly associated with various autoimmune diseases, indicating their decisive role in autoimmune disease development. In this study, we investigated the phenotypes of peripheral V alpha 14+ NK T cells and their TCR-beta repertoire. Peripheral V alpha 14+ NK T cells, comprise two populations, i.e., small and large sized cells, at an equal frequency, belonged to the CD4- CD8- fraction, and are heat stable antigen(bright), macrophage-1bright, B220bright, CD45RBdim, and Mel-14dim, but CD5-, distinct from thymic NK T cells. TCR-beta analysis clearly showed that peripheral V alpha 14+ NK T cells utilized two to three dominant invariant TCR-beta, such as V beta 8.2 D beta J beta 2.5/V beta 7 D beta J beta 2.1 in the spleen and liver, V beta 8.2 D beta J beta 2.5/V beta 8.3 D beta J beta 2.2/V beta 7 D beta J beta 2.6 in the bone marrow, and V beta 7 D beta J beta 2.1/V beta 3 D beta J beta 1.2 in intestinal intraepithelial lymphocytes. Judging from the unusual surface phenotypes, such as heat stable antigen, macrophage-1, B220, CD45RBdim, and Mel-14dim, which are known to be T cell activation markers, peripheral V alpha 14+ NK T cells may always be activated under physiologic conditions, resulting in the oligoclonal expansion of V alpha 14+ NK T cells with different invariant TCR-beta in different peripheral organs. The unique features of V alpha 14+ NK T cells are discussed.

[Volume loading experiment in dogs with large area infarction of right and left ventricles]

In order to study volume loading effect on large area myocardial infarction (MI) in right and left ventricles, large area MI in both ventricles and cardiogenic shock in 12 dogs were induced by occluding coronary arteries. Left ventricular systolic pressure (LVSP) and +/- dp/dt max. dropped markedly by 54%, 51% and 47% respectively, whereas right ventricular systolic pressure (RVSP) and +/- dp/dt max. fell by 9%, 25% and 27% respectively. The condition was obviously worse by rapid volume loading (dextran, 30 ml/kg, i.v. in 20 min.) in group I (n = 6), leading to increased retrograde beat of right ventricle, further decrease of +/- dp/dt max. in both ventricles, significant increase of right atrial pressure (RAP) and left ventricular and diastolic pressure (LEVDP) (2.9 +/- 0.2 kPa, P < 0.01 and 5.0 +/- 0.3 kPa, P < 0.001, respectively), and even ventricular fibrillation. Shock was reversed by combined treatment of dopamine (10 micrograms/kg.min) and glyceryl trinitrate (1 microgram/kg.min) in group II (n = 6) in 30 min, showing evident increase of arterial pressure, cardiac output, LVSP and +/- dp/dt max. without rise in RAP and LVEDP.

Sympathetic outflow response to muscle during vestibular stimulation in humans

To observe the effects of caloric vestibular stimulation on muscle sympathetic nerve activity (MSNA) in humans, 14 healthy volunteers were monitored in a supine position by electrocardiogram (ECG), blood pressure (BP), electro-oculogram (EOG). MSNA was monitored by a double recording technique of microneurography from the bilateral tibial nerves. Caloric vestibular stimulation was loaded by injecting 50 ml 44 degrees C warm water and 50 ml 10 degrees C cold water alternately into the external meatus for 1 min. Nystagmus was evoked in all cases by cold stimulation and in some cases by hot stimulation. The nystagmus evoked by cold stimulation was more intense than that by hot stimulation. MSNA was enhanced by either cold or hot stimulation; however, the enhancement mode differed between cold and hot stimulation. Cold stimulation evoked two peaks of MSNA while hot stimulation elicited only one peak. The first peak (404.5 +/- 115.4% with control value set at 100%, mean +/- SE) was estimated to be caused by cold stimulation on the skin of the external meatus while the second peak (379.2 +/- 65.3%) seemed to be the result of vestibular stimulation. With hot stimulation, the response peak of MSNA was 243.3 +/- 28.1%. In general, MSNA was enhanced after vestibular stimulation with MSNA increases was proportional to the stimulated level of the vestibular system.

V alpha 14+ NK T cells: a novel lymphoid cell lineage with regulatory function

A novel lymphoid lineage, NK T cells, was recently found. The NK T cells are the major population in the periphery comprising 5% of splenic T cells and 40% of bone marrow T cells. They express a unique TCR composed of invariant V alpha 14J alpha 281 and V beta 8.2 together with NK receptor (NKRPI). Surprisingly, the invariant V alpha 14+ TCR is exclusively expressed on NK T cells but not on conventional T cells. As the selective decrease in V alpha 14+ NK T cell population in the periphery is tightly correlated with autoimmune disease development, V alpha 14+ NK T cells control development of autoimmune diseases. We also found that V alpha 14 TCR gene rearrangement and transcripts were detected at an early embryogenesis (d9.5) before the thymus formation. Therefore NK T cells are in the distinct category from conventional T cells. The target of NK T cells is found to be CD1 (class 1b, monomorphic class I MHC-like molecule) present on bone marrow-derived cells and is killed by Fas-FasL interaction or perforin-mediated mechanisms. These results indicate that NK T cells consist of an immunoregulatory system different from defense system in terms of homogeneous repertoire, extrathymic development in early stage of gestation, and their regulatory functional role.