Distribution and depression of the GABA(B) receptor in the spinal dorsal horn of adult rat

gamma-Aminobutyric acid (GABA) is a principal inhibitory neurotransmitter in vertebrate nervous system. The metabotropic receptor for GABA, GABA(B) receptor, is characterized as a G protein-coupled receptor subtype. In the present study, GABA(B) receptor-like immunoreactivity (GABA(B)R-LI) in the rat spinal cord and dorsal root ganglion (DRG), as well as GABA(B) receptor-mediated depression in the spinal dorsal horn were examined by using immunohistochemistry and whole-cell voltage-clamp recording technique, respectively. Under light microscope, GABA(B)R-LI was densely found in laminae I and II of the dorsal horn. DRG cells of various diameters also showed GABA(B)R-LI. Electron microscopy further revealed that GABA(B)R-LI was also localized in terminals of myelinated, unmyelinated fibers as well as the somatodendritic sites of dorsal horn neurons. Bath application of a GABA(B) receptor agonist, baclofen (10 microM, 30 s), induced a slow outward (inhibitory) current in dorsal horn neurons. This slow current was depressed when the postsynaptic G protein-coupled receptor was inhibited, indicating the postsynaptic action of baclofen. Under the condition of postsynaptic GABA(B) receptor being inhibited, baclofen (10 microM, 60 s) depressed large (Abeta) and fine (C, Adelta) afferent fiber-evoked monosynaptic excitatory postsynaptic currents, indicating presynaptic inhibition of GABA(B) receptor on elicited neurotransmitter release. Taken together, the results suggest that baclofen-sensitive GABA(B) receptor is expressed pre- and postsynaptically on primary afferent fibers and neurons in the spinal dorsal horn; activation of GABA(B) receptor in the dorsal horn postsynaptically hyperpolarizes dorsal horn neurons and presynaptically inhibits primary afferents.

Chiral recognition by CD-sensitive dimeric zinc porphyrin host. 1. Chiroptical protocol for absolute configurational assignments of monoalcohols and primary monoamines

A general microscale protocol for the determination of absolute configurations of primary amino groups or secondary hydroxyl groups linked to a single stereogenic center is described. The chiral substrates are linked to the achiral trifunctional bidentate carrier molecule (3-aminopropylamino)acetic acid (1, H(2)NCH(2)CH(2)CH(2)NHCH(2)COOH) and the resultant conjugates are then complexed with dimeric zinc porphyrin host 2 giving rise to 1:1 host/guest sandwiched complexes. These complexes exhibit exciton-coupled bisignate CD spectra due to stereodifferentiation leading to preferred porphyrin helicity. Since the chiral sense of twist between the two porphyrins in the complex is dictated by the stereogenic center of the substrate, the sign of the couplet determines the absolute configuration at this center. The twist of the porphyrin tweezer in the complex can be predicted from the relative steric sizes of the groups flanking the stereogenic center, such that the bulkier group protrudes from the complex sandwich. In certain alpha-hydroxy esters and alpha-amino esters, electronic factors and hydrogen bonding govern the preferred conformation of the complex, and hence the CD spectra.

Chiral recognition by CD-sensitive dimeric zinc porphyrin host. 2. Structural studies of host-guest complexes with chiral alcohol and monoamine conjugates

A structural study of complexes formed between a dimeric zinc porphyrin tweezer (host) and chiral monoalcohols and monoamines derivatized by a bidentate carrier molecule (guest) confirmed that their CD couplets arise from the preferred porphyrin helicity of 1:1 host-guest complexes. NMR experiments and molecular modeling of selected tweezer complexes revealed that the preferred conformation is the one in which the L (larger) group protrudes from the porphyrin sandwich; this preferred helicity of the complex determines the CD of the complexes. It was found that the porphyrin ring-current induced (1)H chemical shifts and molecular modeling studies of the complex lead to the assignments of relative steric size of the L (large)/M (medium) substituents attached to the stereogenic center. The assignments, in turn, are correlated with the sign of the CD exciton couplet that establishes the absolute configuration at the stereogenic center. Variable-temperature NMR experiments proved that the observed increase in CD amplitude at lower temperatures derives from conformational changes in the preferred offset geometry between two porphyrin rings.

Prostaglandin EP3 receptor protein in serotonin and catecholamine cell groups: a double immunofluorescence study in the rat brain

Prostaglandin E(2) exerts diverse physiological actions in the central nervous system with unknown mechanisms. We have reported the immunohistochemical localization of the EP3 receptor, one of the prostaglandin E receptor subtypes, in various brain regions including many monoaminergic nuclei. In the present study, a double immunofluorescence technique with an antibody to EP3 receptor and antibodies to markers for monoamine neurons was employed to examine the expression of the receptor in serotonin and catecholamine neurons, and to reveal the distribution of the receptor-expressing monoamine neurons in the rat brain. Almost all serotonergic cells in the medulla oblongata (B1-B4) exhibited EP3 receptor-like immunoreactivity, whereas mesencephalic and pontine serotonergic cell groups (B5-B9) contained relatively small populations of EP3 receptor-immunoreactive cells. In the catecholaminergic cell groups, many of the noradrenergic A7 cells in the subcoeruleus nucleus showed immunoreactivity for the receptor. The locus coeruleus exhibited EP3 receptor-like immunoreactivity densely in the neuropil and occasionally in neuronal cell bodies, all of which were immunopositive for dopamine beta-hydroxylase, as observed by confocal laser microscopy. Many of the other noradrenergic and adrenergic cell groups contained small populations of EP3 receptor-like immunoreactive cells. In contrast, no EP3 receptor-like immunoreactivity was detected in the noradrenergic A2 and A4, the adrenergic C2, and all the dopaminergic cell groups. The expression of EP3 receptor by most of the serotonergic, noradrenergic and adrenergic cell groups suggests that prostaglandin E(2) modulates many physiological processes mediated by widely distributed monoaminergic projections through activation of the EP3 receptor on the monoaminergic neurons; for instance, it may modulate nociceptive and autonomic processes by affecting the descending serotonergic pathway from the raphe magnus nucleus to the spinal cord.

Effect of two conserved amino acid residues on DREB1A function

Transcription factors of the DREBP subgroup and the EREBP subgroup contain conserved DNA-binding domains called AP2/EREBP domains, which specifically bind to DRE cis-element and GCC-box, respectively. The 14th and 19th amino acid residues of AP2/EREBP domains are absolutely conserved in the transcription factors of the DREBP subgroup as well as in the EREBP subgroup. However, these two residues of transcription factors of the DREBP subgroup are different from those of the EREBP subgroup. To assess the functional significance of these two residues in binding to the target sequence, the Val (14th residue) and Glu (19th residue) of the AP2/EREBP domain of DREB1A (a transcription factor of the DREBP subgroup) were mutated individually or doubly to Ala and Asp, respectively. This made the 14th and 19th amino acid residues of mutant DREB1A identical to the corresponding residues of transcription factors of the EREBP subgroup. Yeast in vivo analysis showed that: 1) on a selective medium plate of SD/His- Ura- Trp- + 30 mM approximately 60 mM 3-AT, the growth of yeast cells containing HIS and lacZ double reporter genes was normal in the transformation of the 19th singly mutated DREB1A, obviously inhibited in the transformation of the 14th singly mutated DREB1A, and seriously inhibited in the transformation of the 14th/19th doubly mutated DREB1A; 2) quantitative assay of beta-galactosidase activity showed that the intensities of lacZ expression decreased in the transformations of the 14th singly mutated and 14th/19th doubly mutated types. The experimental results revealed that the 19th site mutation did not affect the binding of the DREB1A transcription factor to the DRE cis-element; the 14th site mutation obviously inhibited their binding; and the double mutation of the 14th/19th sites seriously inhibited their binding. This suggests that the conserved Val (14th) and Glu (19th) residues are crucial in the regulation of the binding activity of DREB1A to the DRE cis-element.

Morphological features and electrophysiological properties of serotonergic and non-serotonergic projection neurons in the dorsal raphe nucleus. An intracellular recording and labeling study in rat brain slices

The morphology and electrophysiological properties of serotonergic and non-serotonergic projection neurons in the dorsal raphe nucleus (DRN) of the rat were examined in frontal brain slices. Biocytin was injected intracellularly into the intracellularly recorded neurons. Then the morphology of the recorded neurons was observed after histochemical visualization of biocytin. The recorded neurons extending their main axons outside the DRN were considered as projection neurons. Subsequently, serotonergic nature of the neurons was examined by serotonin (5-HT) immunohistochemistry. The general form of the dendritic trees is radiant and poorly branching in both 5-HT- and non-5-HT neurons. However, the dendrites of the 5-HT neurons were spiny, whereas those of the non-5-HT neurons were aspiny. The main axons of both 5-HT- and non-5-HT neurons were observed to send richly branching axon collaterals to the DRN, ventrolateral part of the periaqueductal gray and the midbrain tegmentum. In response to weak, long depolarizing current pulses, the 5-HT neurons displayed a slow and regular firing activity. The non-5-HT neurons fired at higher frequencies even when stronger current was injected. Some other differences in electrophysiological properties were also observed between the 5-HT-immunoreactive spiny projection neurons and the 5-HT-immunonegative aspiny projection neurons.

Hypoxia in radiation-induced blood-spinal cord barrier breakdown

The vascular endothelial cell is believed to be a major target cell of radiation-induced injury to the central nervous system. Dysfunction of the blood-brain barrier is associated with radiation-induced white matter lesions. The aim of this study was to determine the role of hypoxia in radiation-induced blood-brain barrier disruption. Adult rats were irradiated with graded single doses of 0-22 Gy to the cervical spinal cord. At various times up to 28 weeks after radiation, blood-spinal cord barrier (BSCB) permeability was assessed using immunohistochemistry with antialbumin antibody and gamma counting of (99m)Tc-diethylenetriamine pentaacetic acid. Expression of vascular endothelial growth factor (VEGF) was assessed using immunohistochemistry and in situ hybridization. Hypoxia was assessed using two 2-nitroimidazole markers, [(125)I]iodoazomycin arabinodise and 2-(2-nitro-1H-imidazol-l-yl)-N-(2,2,3,3,3,-pentafluoropropyl) acetamide (EF5), with binding in the rat spinal cord measured using gamma counting and immunohistochemistry, respectively. In the nonirradiated rat spinal cord, there was no evidence of BSCB disruption or VEGF expression. After 16-22 Gy, there was a dose-dependent increase in albumin staining and (99m)Tc-diethylenetriamine pentaacetic acid activity beginning at 16 weeks, consistent with barrier breakdown. A similar dose-dependent increase in white matter astrocytes that showed immunoreactivity and in situ hybridization signals for VEGF was observed. No increase in VEGF-positive cells was observed in gray matter. By 20 weeks after 20-22 Gy, animals developed white matter necrosis associated with diffuse albumin staining. Irradiated rat spinal cord showed a dose (16-22 Gy)- and time-dependent (16-20 weeks after 22 Gy) increase in [(125)I]iodoazomycin arabinodise accumulation compared to nonirradiated controls. A similar pattern of dose- and time-dependent EF5 immunoreactivity was also observed in white matter. Areas of EF5 expression and VEGF in situ signals colocalized with areas of albumin immunoreactivity. It is concluded that there is a dose-dependent temporal and spatial association of hypoxia, VEGF up-regulation, and radiation-induced BSCB dysfunction. Hypoxia may provide the signal for VEGF up-regulation and perpetuate endothelial permeability damage in the central nervous system after ionizing radiation.

Epidemic of Potato virus Y and Cucumber mosaic virus in Henan Province Tobacco

Flue-cured tobacco is an important crop in Henan Province, China. During the 2000 growing season, many tobacco plants showed various degrees of mottling, mosaic, vein clearing, or vein necrosis in most of the counties. Some plants even died at an early stage of growth. A survey was conducted in May-June in several tobacco-growing counties, and the incidence of symptomatic plants in individual fields ranged from 10 to 85%. The most widely planted tobacco varieties, NC89, K326, and K346, were highly susceptible. Symptomatic plants were collected from Jiaxian and Xiangcheng counties and samples were tested by enzyme-linked immunosorbent assay for Tobacco mosaic virus (TMV), Cucumber mosaic virus (CMV), Potato virus Y (PVY), and Potato virus X (PVX). Of 65 samples tested, 21 were positive for only PVY, 16 positive for only CMV, one each was positive for only TMV or PVX. Nineteen samples were doubly infected with various combinations of these viruses and six were infected with combinations of three viruses. The causal agent(s) in the remaining sample could not be determined. In total, CMV was detected in 40 samples, PVY in 38, PVX in 10, and TMV in 7 samples. TMV and CMV used to be the most important viruses and PVY occurred only rarely. But PVY has become prevalent in Henan and in neighboring Shandong province (2). CMV and TMV were reported to be the most prevalent viruses in Shanxi (1) and Fujian Provinces (3). Because resistant varieties are not available, and mixed infections are more common, the results presented here explain why huge damage is occurring in tobacco crops in recent years. Some varieties are partially resistant to TMV and CMV but the varieties commonly grown are highly susceptible to PVY. Therefore, breeding for resistance to viruses, especially to PVY, is urgent to control the occurrence of tobacco viral diseases. References: (1) J. L. Cheng et al. Acta Tabacaria Sin. 4:43, 1998. (2) J. B. Wang et al. Chinese Tobacco Sci. 1:26, 1998. (3) L. H. Xie et al. Acta Tabacaria Sin. 2:25, 1994.

[Prediction and evaluation of heterosis of beef cattle and their application]

The genetic structure and genetic variation of eight beef cattle cross parents populations were analyzed by six microsatellite loci, and heterosis of beef cattle was predicted. On the basis of microsatellite analysis, the effect of 18 cross combinations was estimated by the method of individual animal model BLUP. A new method of molecular quantitative genetics that select best of all cross combination was submitted. The results showed that the combinations with Hereford Limousine and Charolais as paternal parent are better than others in Fengning and Longhua regions; the combinations with Limousine Angus and Hereford as paternal parent are better than others in Zanhuang regions; the combinations with Hereford Limousine and Piemontese as paternal parent are better than others in Funing regions. Effect of three breeds cross is better than two breeds.

Collateral projections of nucleus raphe dorsalis neurones to the caudate-putamen and region around the nucleus raphe magnus and nucleus reticularis gigantocellularis pars alpha in the rat

It was examined whether or not the nucleus raphe dorsalis (RD) neurons projecting to the caudate-putamen (CPu) might also project to the motor-controlling region around the nucleus raphe magnus (NRM) and nucleus reticularis gigantocellularis pars alpha (Gia) in the rat. Single RD neurons projecting to the CPu and NRM/Gia by way of axon collaterals were identified by the retrograde double-labeling method with fluorescent dyes, Fast Blue and Diamidino Yellow, which were injected respectively into the CPu and NRM/Gia. Then, serotonin (5-HT)-like immunoreactivity of the double-labeled RD neurons was examined immunohistochemically; approximately 60% of the double-labeled RD neurons showed 5-HT-like immunoreactivity. The results indicated that some of serotonergic and non-serotonergic RD neurons might control motor functions simultaneously at the levels of the CPu and NRM/Gia by way of axon collaterals.

Origins of spontaneous and noxious stimuli-evoked miniature EPSCs in substantia gelatinosa

The origins of spontaneous and noxious stimuli-evoked glutamatergic miniature excitatory postsynaptic currents (mEPSCs) in substantia gelatinosa (SG) neurons were investigated by using whole-cell voltage-clamp technique on adult rat spinal cord slice. The properties of mEPSCs of SG neurons from rats either neonatally capsaicin-treated or sciatic nerve ligated showed no difference from those of intact SG neurons, indicating independence of spontaneous mEPSCs on primary afferent fibers. In the presence of tetrodotoxin (TTX), capsaicin, which noxiously stimulated fine primary afferent fibers, caused increase of the mEPSCs frequency, but did not affect the amplitude profiles or mean amplitudes. TTX affected neither the spontaneous mEPSCs nor capsaicin-induced mEPSCs frequency increase. The results suggest that spontaneous mEPSCs in SG are mediated by presynaptic spontaneous glutamate release predominantly originating from interneuron terminals rather than from primary afferent terminals; under noxious stimulation, however, mEPSCs frequency increase is mediated by primary afferent excitation.

Derivative matrix isopotential synchronous fluorescence spectroscopy for the direct determination of 1-hydroxypyrene as a urinary biomarker of exposure to polycyclic aromatic hydrocarbons

Urinary 1-hydroxypyrene is a biomarker in the measurement of human exposure to polycyclic aromatic hydrocarbons. A rapid and simple derivative isopotential synchronous fluorescence method was developed for the direct determination of 1-hydroxypyrene in urine. A length of iso-intensity route was scanned on the three-dimensional fluorescence spectrum of urine and this result was combined with that from derivative technique. Thus the strong background signals of urine were removed and the 1-hydroxypyrene can be determined directly in urine without tedious pre-separation. The derivative isopotential synchronous fluorescence spectrum was directly obtained from a single scan on a spectrofluorometer, which further simplified isopotential synchronous fluorescence technique. The recoveries of 93% to 115% were obtained for 1-hydroxypyrene added to urine.

Intracellular labeling study of neurons in the superficial part of the magnocellular layer of the medullary dorsal horn of the rat

Morphology and electrical membrane properties of neurons in the superficial part of the magnocellular layer of the rat medullary dorsal horn (MDH: caudal subnucleus of the spinal trigeminal nucleus) were examined by using horizontal slice preparations. Intracellular recording and biocytin-injection combined with histochemical and immunohistochemical staining were done. Twenty-four neurons were examined successfully and classified into projection neurons (PNs) and intrinsic neurons (INs). The PNs were further divided into type I PNs (I-PNs) and type II PNs (II-PNs). The I-PNs sent axons to the medullary reticular formation; the II-PNs sent axons to the interpolar subnucleus of the spinal trigeminal nucleus but had no axons extending to the medullary reticular formation. The INs that sent no axons to the brain regions outside the MDH were also divided into small INs with spiny dendrites (INSSs) and large INs with aspiny dendrites (INLAs). The dendritic fields of the PNs extended to laminae I and II of the MDH and occasionally further to the spinal tract of the trigeminal nerve, whereas those of the INs were confined within the magnocellular layer of the MDH. The axonal branches of each IN formed a dense axonal mesh around the cell body of the parent neuron. Although the main bodies of the axonal fields of the INs were located in the magnocellular layer, some axonal branches extended to laminae I and II of the MDH. Immunoreactivity for NK1 receptor (substance P receptor) was found in approximately half of the PNs but not in the INs. Although no strong correlation was found between morphology and electrical membrane properties, there were some differences in electrical properties among the morphologically classified neuron groups, e.g., hyperpolarizing sag was observed in some PNs but not in the Ins; inward rectification was observed in some of the INSSs and INLAs but not in the PNs; the slow ramp depolarization and the slow afterdepolarization were observed in all INSSs examined but not in the PNs or INLAs.

A nine-year prospective study on the incidence of childhood type 1 diabetes mellitus in China

To investigate the epidemiological characteristics of childhood type 1 diabetes mellitus in China, newly diagnosed cases of type 1 diabetes with an onset age under 15 years were retrospectively registered by 23 local centers in China following a standardized protocol on the basis of the nationwide registry established by the WHO DiaMond Project China Participating Center, Chinese Academy of Preventive Medicine (CAPM). A population of about 24 million children were covered in the defined areas. A two-sample capture-recapture method was used to estimate case ascertainment. Between 1988 and 1996, 903 diabetic cases were registered in 9 ethnic groups. The overall ascertainment corrected incidence rate (IR) was 0.59 per 100,000 person-year. The IR was 0.52/100,000 (95% CI: 0.50-0.54) for males and 0.66/100,000 (95% CI: 0.64-0.68) for females. The standardized ascertainment corrected IR by the national age-specific population in 1990 was 0.57 per 100,000 person-year. The incidence among various ethnic groups ranged from 0.25/100,000 to 3. 06/100,000. The IRs increased with northern latitude, and the IR of Han population was significantly higher in North China compared with South China (0.67 versus 0.53 per 100,000 respectively, P < 0.01). A correlation model of incidence and calendar time showed that the IR increased significantly between 1988 and 1996 (r = 0.86, P = 0.0027). The relative risk (RR) of type 1 diabetes mellitus for different age-groups estimated by a Poisson regression model showed that taking RR as 1.00 for age-group from 0 to 4 years, the RR for age-group from 5 to 9 year and from 10 to 14 year was 2.30 and 3.60 respectively. The standardized ascertainment corrected IR of childhood type 1 diabetes mellitus in China in much lower than in other countries. The geographic and ethnic variability of the incidence suggests that both genetic and environmental factors play a role in the development of childhood diabetes in China.

Rapid simultaneous determination of four anthracene derivatives using a single non-linear variable-angle synchronous fluorescence spectrum

A rapid, simple and inexpensive spectrofluorimetric method has been developed for the simultaneous identification and quantification of anthracene (ANT), 9,10-dimethylanthracene (DIM), 2-aminoanthracene (AMI) and dibenz[ah]anthracene (DIB). A well-resolved spectrum for the mixture of these four compounds is obtained based on a single non-linear variable-angle synchronous scanning. The linear concentration ranges are 10-1,000, 5-500, 50-1,000 and 10-200 ng mL(-1) for ANT, DIM, AMI and DIB, respectively, at lambdaex/lambdaem = 358/380, 399/408, 414/465 and 298/394 nm, respectively. The analyses are performed in cyclohexane. Recoveries of 90.0-111.0% in synthetic mixtures are obtained. The detection limits are 2.0 ng mL(-1) for DIM, 2.7 ng mL(-1) for ANT, 15.8 ng mL(-1) for AMI and 4.2 ng mL(-1) for DIB. The method has also been applied to several real water samples with satisfactory results.

MMP and TIMP gene expression in head and neck squamous cell carcinomas and adjacent tissues

OBJECTIVE

To compare the frequency of gene expression of matrix metalloproteinases (MMP) stromelysins -1, -2 and -3 (MMP-3, -10, and -11), matrilysin (MMP-7), MTI-MMP (MMP-14), and of TIMPs (Tissue Inhibitors of MMPs) -1, -2, -3 and -4 in head and neck squamous cell carcinomas with those of matched adjacent normal tissues.

MATERIALS AND METHODS

The present study included 20 surgically removed head and neck squamous cell carcinomas, seven of which were accompanied by matched adjacent oral mucosa excised from the border of the specimens outside the tumor area. RNA isolated from tumors and control samples was subjected to RT-PCR using primers specific for MMP-3, -7, -10, -11 and -14 and for TIMPs -1, -2, -3, and -4.

RESULTS

Our findings demonstrate that each of the five MMP genes studied were expressed in essentially all the tumors, while the adjacent marginal tissue samples showed a more varied picture: while stromelysin-3 was located to a majority of the marginal samples, matrilysin was expressed in four of seven adjacent samples, stromelysin-1 and MTI-MMP genes were each expressed in three of these samples, and stromelysin-2 transcript was only expressed in two marginal tissue samples. Whereas TIMP-1 and TIMP-2 transcripts were identified in all tumor and adjacent tissue samples studied, TIMP-3 was expressed, albeit often at low levels, in 17 of 20 tumor samples but only in three of seven adjacent tissues. The novel TIMP-4 gene was not expressed at all.

CONCLUSIONS

Specific MMP (MMP-3, -7, -10, -14) and TIMP-3 transcripts observed in head and neck squamous cell carcinomas compared to their frequency in specimens of matching tissues provide important information about expression of extracellular matrix degrading enzymes and their tissue inhibitors in head and neck carcinomas.

Distribution of substance P-like immunoreactive fibers in feline temporomandibular joint

OBJECTIVE

To study the distribution of substance P-like immunoreactive fibers in feline temporomandibular joint.

METHODS

The immunohistochemical PAP method was used for the investigation of the distribution of substance P-like immunoreactive fibers in feline temporomandibular joint.

RESULTS

The TMJ capsule and the anterior and posterior disc attachments all contained SP-immunoreactive nerve fibers, but the medium fibers in diameter were mainly observed. The density of the distribution of SP-positive nerve fibers was the highest in the subsynovium of the TMJ capsule. The density of distribution was similar in the anterior and posterior disc attachments, but lower than in the subsynovium and the lateral joint capsule. Such fibers in the synovial membrane were sparser, and a part of the fibers were seen around the thin blood vessels in all the foregoing tissues.

CONCLUSION

These results provide the morphological data for exploring the neurobiological mechanisms of temporomandibular joint disorder and its pain.

Fucosyl transferase (H) transgenic heart transplants to Gal-/- mice

BACKGROUND

We have previously described the rejection of Gal+ mouse hearts by mice lacking Gala(1,3)Gal (Gal-/-) and demonstrated this to be a model of xenogeneic hyperacute rejection (HAR) which would occur in pig-to-human/primate xenotransplantation, where Gal+ antibody (Ab) and complement (C') mediate HAR. To reduce the amount of Gal present we used fucosyl transferase (H) as a transgene, H transferase competes for the same substrate as Gal transferase and reduces Gal expression by >90%.

METHODS

Gal-/- mice received a heart graft from C57BL/6 Gal+ or H transgenic mice and additional Gal Ab and C' provided; HAR was monitored by direct observation for up to 90 min, or by palpation thereafter. When grafts were rejected they were examined macro- and microscopically.

RESULTS

H transgenic mice were used as donors to Gal-/- mice; it was found that: 1) C57BL/6 or H transgenic hearts were not rejected by Gal-/- recipients within 90 min in the absence of additional Gal Ab. 2) If additional Gal Ab and C' were provided as fresh normal human serum (NHS), Gal+ (C57BL/6) grafts were rejected by Gal-/- mice in approximately 34 min, whereas H transgenic hearts mostly lasted up to 17 hr, but were then rejected. The histological appearances showed features of both Arthus and Shwartzmann phenomena. 3) Mice hyperimmunized with Gal with anti-Gal titers of >1:20,000, rejected Gal+ grafts in 31 min; the survival was prolonged to 75 min with the H transgenic hearts.

CONCLUSION

The presence of the H transgene in donor hearts transplanted to naive Gal-/- mice delays the onset of HAR, but rejection ultimately occurs; if the mice are hyperimmune earlier rejection occurs. The expression of the H transgene alone is insufficient to avoid HAR in the Gal-/- mouse model; the presence of other transgenes and techniques will be required to give an appropriate increase in survival of pig-to-human/primate grafts.

Synaptic interaction between GABAergic terminals and substance P receptor-positive neurons in rat spinal superficial laminae

AIM

To identify synaptic relationship between gamma-aminobutyric acid (GABA)-containing terminals and substance P receptor-positive neurons in the superficial dorsal horn of rat spinal cord.

METHODS

A combination of preembedding immunoperoxidase staining for substance P receptor with postembedding immunogold staining for GABA was employed.

RESULTS

Intense substance P receptor-expressing neurons were concentrated in medial half of the lamina I and the outer lamina II of the spinal cord. Under electron microscopy, substance P receptor immunoreactivity was found mainly in perikarya and dendrites, and deposited along neuronal membranes, in Golgi complex, in rough endoplasmic reticulum and on the surface of mitochondria with patch- or granular-like staining. The double-labeling studies revealed that substance P receptor-expressing dendrites received symmetric synaptic contacts from axonal terminals labeled with immunogold particles indicating GABA. GABA also co-localized with substance P receptors in the dendrites.

CONCLUSION

The synaptic contact between GABA-containing terminal and substance P receptor-expressing neuron provided important morphological evidence for previous pharmacological studies concerning antinociceptive function of GABA in the spinal cord.

[The function of T7 promoter as cis-acting elements for polymerase II in eukaryotic cell]

Using the chlorampheniol acetyltransterase gene as reporter, the function of phage T7 promoter in mammalian cells was studied by inhibition of transcription with alpha-amanitin. The experiment proved that the reporter under T7 promoter was transcribed by RNA polymerase II. Competitive electropho retic mobility shift assay (CEMSA) with TATA box, CAAT box, GC box and octamer showed that the TATA box was competitive molecular for synthetic T7 promoter. It is possible that T7 promoter is bound with TF II D transcription factor. The TATA box and octamer were inserted into Pvu II site upstream from the T7 promoter of pT7CAT. Two recombinant plasmids, pT7TATACAT and pT7OCTCAT, were constructed and transfected into CHO cells. CAT-activity test showed that T7 promoter strength was increased by octamer factor, not by TATA box. These results suggested that T7 promoter functions as cis-acting elements of RNA polymerase II transcriptional system in eucaryotic cells.

Postsynaptic origin of N-methyl-D-aspartate-induced slow currents in substantia gelatinosa neurons: an in vitro voltage-clamp study in adult rat

We investigated whether N-methyl-D-aspartate (NMDA)-induced slow current in substantia gelatinosa (SG) neurons might be of presynaptic or postsynaptic origin. Whole-cell voltage-clamp recordings were made from adult rat spinal cord slices to examine the effect of NMDA receptor upon miniature excitatory postsynaptic currents (mEPSCs) in SG neurons. At a holding potential of -70 mV, bath application of NMDA (10 microM, 30s), an NMDA receptor agonist, affected neither the frequency nor the mean amplitude of mEPSCs, while NMDA induced a slow excitatory membrane current which persisted in the presence of tetrodotoxin. On the other hand, AP-5 (an NMDA receptor antagonist) had no noticeable effects on mEPSCs in the SG neurons tested, while it markedly depressed the NMDA-induced slow currents. The NMDA-induced slow currents varied with the changing of holding potentials (from -70 to 0 mV). The results suggested that the NMDA-induced slow currents in SG neurons were of postsynaptic origin.

Collateral projection of substance P receptor expressing neurons in the medullary dorsal horn to bilateral parabrachial nuclei of the rat

Employing a combination of fluorescent retrograde double labeling and immunofluorescence histochemistry for substance P receptor (SPR), we examined the collateral projection from single SPR-like immunoreactive neurons in the medullary dorsal horn (caudal subnucleus of the spinal trigeminal nucleus) to bilateral parabrachial nuclei in the rat. After injection of fast blue (FB) or diamidino yellow (DY) into the right or left parabrachial nucleus, respectively, single-labeled FB or DY neurons and double-labeled FB/DY neurons were observed mainly bilaterally in laminae I and II of the medullary dorsal horn. Some of the single-labeled FB or DY and double-labeled FB/DY neurons showed SPR-like immunoreactivity, especially in lamina I. In lamina I of left medullary dorsal horn which is ipsilateral to the DY injection into the PBN, the percentages of double-labeled FB/DY neurons to the total number of FB- or DY-labeled neurons were 34.0% or 20.2%, triple-labeled FB/DY/SPR neurons to the total number of FB/DY double-labeled or SPR-like immunoreactive neurons were 22.0% or 2.4%, respectively. In lamina I of the right medullary dorsal horn which is ipsilateral to the FB injection into the PBN, the percentages of double-labeled FB/DY neurons to the total number of FB- or DY-labeled neurons were 12.9% or 59.3%, triple-labeled FB/DY/SPR neurons to the total number of double-labeled FB/DY or SPR-like immunoreactive neurons were 24. 6% or 3.9%, respectively. The results suggest that some of the single SPR expressing neurons in the medullary dorsal horn might be innervated by substance P containing primary afferent fibers and transmit sensory information diffusely to bilateral parabrachial nuclei by way of their axonal collaterals.

KAI1/CD82 gene expression in benign prostatic hyperplasia and late-stage prostate cancer in Chinese

AIM

To evaluate KAI1/CD82 expression in Chinese patients with benign prostatic hyperplasia (BPH) and late-stage carcinoma of prostate (CaP).

METHODS

Thirty Chinese patients with benign prostatic hyperplasia and 34 with CaP (adenocarcinoma clinical stage C and D) were analyzed by means of immunohistochemical methods.

RESULTS

The KAI1/CD82 expression in BPH tissue was all positive, which was uniformly located on the glandular cell membrane at the cell-to-cell borders, but KAI1/CD82 expression in metastasis CaP tissues was either significantly lower than that of BPH or negative, and the immunostaining pattern was not continuous. In late-stage CaP KAI1/CD82 expression was correlated inversely to the pathological grade ( P < 0.05), but not to clinical stage ( P > 0.05).

CONCLUSION

The authors believe that decreased and negative KAI1/CD82 expression in late-stage CaP may be related to tumor progression and metastasis, and appears to be a prognostic marker.

Synaptic relationship of the neurons containing a metabotropic glutamate receptor, MGluR5, with nociceptive primary afferent and GABAergic terminals in rat spinal superficial laminae

Recent pharmacological evidence showed that metabotropic glutamate receptors (mGluRs), particularly mGluRs1/5, had a potential role in spinal nociceptive processing. However, previous morphological studies on mGluRs have been limited mainly to their distribution in the spinal cord. In the present study, electron microscopic immunocytochemistry was employed to identify the synaptic relationship of the neurons containing mGluR5, with nociceptive primary afferent and gamma-aminobutyric acid-ergic (GABAergic) terminals in the superficial dorsal horn of the spinal cord. Nociceptive C- and A(delta)-primary afferent terminals selectively labeled with horseradish peroxidase conjugated to wheat-germ agglutinin were in asymmetric synaptic contacts with or in direct apposition to mGluR5 positive dendritic profiles. The double-labeling studies revealed that mGluR5 immunoreactive dendrites also received symmetric synaptic contacts from axon terminals labeled with immunogold particles indicating GABA. The present demonstration of mGluR5 neurons receiving inputs from both nociceptive primary afferents and GABAergic terminals of presumed interneurons further supports the involvement of mGluR5 in the transmission and modulation of nociceptive information in the spinal cord.

Radiation-induced apoptosis in the neonatal and adult rat spinal cord

This study was designed to characterize radiation-induced apoptosis in the spinal cord of the neonatal and young adult rat. Spinal cords (C2-T2) of 1-, 2- and 10-week-old rats were irradiated with a single dose of 8, 18 or 22 Gy. Apoptosis was assessed histologically according to its specific morphological features or by using the TUNEL assay. Cell proliferation was assessed immunohistochemically using BrdU. Identities of cell types undergoing apoptosis were assessed using immunohistochemistry or in situ hybridization using markers for neurons, glial progenitor cells, microglia, oligodendrocytes and astrocytes. The time course of radiation-induced apoptosis in 1- or 2-week-old rat spinal cord was similar to that in the young adult rat spinal cord. A peak response was observed at about 8 h after irradiation, and the apoptosis index returned to the levels in nonirradiated spinal cords at 24 h. The neonatal rat spinal cord demonstrated increased apoptosis compared to the adult. Values for total yield of apoptosis over 24 h induced by 8 Gy in the neonatal rat spinal cord were significantly greater than that in the adult. Immunohistochemistry studies using Leu7, galactocerebroside, Rip and adenomatous polyposis coli tumor suppressor protein indicated that most apoptotic cells were cells of the oligodendroglial lineage regardless of the age of the animal. No evidence of Gfap or factor VIII-related antigen-positive apoptotic cells was observed, and there was a small number of apoptotic microglial cells (lectin-Rca1 positive) in the neonatal and adult rat spinal cord. In the neonatal but not adult rat spinal cord, about 10% of the apoptotic cells appeared to be neurons and were immunoreactive for synaptophysin. Labeling indices (LI) for BrdU in nonirradiated 1- and 2-week-old rat spinal cord were 20.0 and 16.3%, respectively, significantly greater than the LI of 1.0% in the 10-week-old rat spinal cord. At 8 h after a single dose of 8 Gy, 13.4% of the apoptotic cells were BrdU-positive in 10-week-old rat spinal cord, whereas 62.4 and 44.1% of the apoptotic cells showed BrdU incorporation in 1- and 2-week-old rat spinal cord, respectively. Regardless of the age of the animal, the apoptosis indices in BrdU-positive cells were greater than those in BrdU-negative cells. We conclude that the neonatal spinal cord demonstrates a greater level of apoptosis after exposure to ionizing radiation than the young adult spinal cord. This increase in apoptosis may be associated in part with the greater percentage of proliferating cells in the neonatal spinal cord, which demonstrate a greater level of radiation-induced apoptosis than nonproliferating cells.