[3D finite element analysis of stress distributions in supporting tissues of clasp-type partial dentures of transferring occlusion force]

OBJECTIVE

To provide a theoretical basis for clinical application of the clasp-type partial denture of transferring occlusion force, the stress distributions in its supporting tissue were analyzed.

METHODS

The 3D finite element model was made, and the features of stress distributions in the supporting tissues of the clasp-type partial dentures which had different rest recess angles were discussed.

RESULTS

The medial stress component was significantly larger than the distal one in the supporting tissue around main abutment root. When the rest recess angles were equal or greater to 60 degrees, the stress values were greatly reduced in the supporting tissue around the roots of the three abutments. When the rest recess angle reached 75 degrees, the stress values in the supporting tissue around the main abutment root wore decreased by 30% than the angle 0 degree and by 52% than the angle 45 degrees, the stress values in the supporting tissue around the root of second abutment (adjacent to the main abutment) were wholly increased by 44% than the angle 0 degree and reduced by 23% than the angle 45 degrees, the stress values in supporting tissue around the root of third abutment (outside of the second abutment) were wholly increased by 53% than the angle 0 degree and decreased by 31% than the angle 45 degrees, the stress values in the medial root of the main abutment were reduced by 73%.

CONCLUSION

The clasp-type partial denture can resolve part of the occlusion force into two components the medial and distal components, and the occlusion force is distributed to several abutments, at the same time the conversed force components can be canceled by each other. So the whole stress values are greatly reduced and the stress around abutment root is greatly decreased. As a result the damage to the abutment will be eliminated. A design with centralized multi abutments and multi fixed bodies are used in this denture, which are more fixed and stable and have no obvious sinkage in the plate base. Therefore, the mastication function can be satisfactorily recovered, and the reasonable rest recess angle for the clasp-type partial denture of transferring occlusion force is about 75 degrees.

Characterization and transcriptional profiles of two rice MADS-box genes

The plant MADS-box gene family plays a key role in plant development, especially in flower development. We designed degenerate primer according to the MADS-box conserved region and isolated two cDNA from rice, FDRMADS6 and FDRMADS7, which are homologous to AP1. RT-PCR expression analyses by using total RNA isolated from root, shoot and flower showed that the FDRMADS6 transcript was detectable only in flower while FDRMADS7 was expressed in all three tissues. In situ hybridization experiments indicated that at the early stage of rice flower development, the transcripts of FDRMADS6 and FDRMADS7 were detected in the spikelet apical meristem, which were same as AP1. At the late stage, when flower organ primordia started differentiating, the expression of FDRMADS6 appeared to be specifically localized in developing stamens and the pistil primordia, while the transcripts of FDRMADS7 were detectable abundantly throughout the organ primordia. Our results suggest the two MADS-box genes may be members of the AP1 family, but may have different functions.

beta2-adrenoceptor gene polymorphisms and blood pressure variations in East Anglian Caucasians

OBJECTIVE

The amino-terminal polymorphisms, Arg16Gly and Gln27Glu, of the beta2-adrenergic receptor (beta2AR) have been shown to affect regulation of the receptor expression by an agonist in cell culture studies. The Arg16Gly polymorphism has also been recently shown to be associated with essential hypertension. We therefore evaluated whether the amino-terminal polymorphisms of beta2AR are associated with hypertension in a Caucasian population.

SUBJECTS AND METHODS

We performed an association study in 298 hypertensive patients and an equal number of age-matched normotensive controls from the East Anglian region, with blood pressure assessed categorically and quantitatively. We also examined the influence of the amino-terminal polymorphisms on blood pressure response to beta-blockade in 144 of the patients randomly assigned to this class of drug. Genotyping of the Arg16Gly polymorphism was undertaken by a newly designed mismatched polymerase chain reaction (PCR) and digestion with Nde I, whereas the Gln27Glu polymorphism was genotyped by PCR followed by Fnu4H I cleavage.

RESULTS

We found no differences in the genotype or allele frequencies of the beta2AR polymorphisms between hypertensive and normotensive participants. There was also no association between the beta2AR genotypes and variations in either basal blood pressure or the blood pressure response to a beta-blocker.

CONCLUSION

These findings suggest that the amino-terminal polymorphisms of the beta2AR gene are unlikely to constitute major susceptibility for essential hypertension in the East Anglian population.

A genome-wide search for susceptibility loci to human essential hypertension

We undertook a systematic search of the entire human genome with the affected sibling-pair model to identify major susceptibility loci to essential hypertension. Affected nuclear families (n=263) were recruited and divided according to definite or probable genetic contribution to hypertension depending on number of hypertensive siblings. The largest nuclear families were first screened with a set of microsatellite markers. Regions on the genome with P<0.05 were tested against the second set of smaller families. An exclusion map was generated to identify regions in which hypertension-causing genes are unlikely to reside. Sibling-pair linkage analysis identified a single locus on chromosome 11q (P<0.004) in the first pass. A second pass with nuclear families that had only affected sibling pairs was, as expected, insufficient to support linkage to 11q. Multipoint exclusion-linkage analysis showed that 3 genetic loci are necessary to explain familial aggregation of essential hypertension. Our preliminary findings suggest that no single region within the human genome contains genes with a major contribution to essential hypertension. We show that the disease is indeed polygenic, with each gene providing a relatively small risk. Our exclusion map will help future investigators to concentrate on areas likely to contain these genes. The region on chromosome 11 is the first to point to a new candidate gene for hypertension that has arisen out of a genome search, but replication of these results at a higher significance is necessary before positional cloning can be justified.

The expression kinetics of myogenin in facial muscle denervation

OBJECTIVE

To study the expression kinetics of myogenin in long-term denervated facial muscle and to explore the possibility of gene therapy for facial muscle paralysis with myogenin gene.

MATERIALS AND METHODS

In 48 New Zealand rabbits, buccal muscle paralysis of one side was produced by excision of 1 cm segment buccal branch of the facial nerve. The opposite side served as controls. The animals were sacrificed and the buccal muscles of both sides were removed for examination at 1 day, 3 days, 1 week, 2 weeks, 1 month, 2 months, 4 months, and 6 months after the initial operation. The myogenin expression in denervated and innervated buccal muscles was analyzed by Western blot. Satellite cell proliferation was detected with proliferating cell nuclear antigen (PCNA) analysis. Muscle nucleic acid concentration was determined through acridine orange (AO) staining method.

RESULTS

Myogenin expression increased to the highest level at 3 days after denervation, thereafter it gradually decreased. The Western blotting signal for myogenin intensified again after 1 month and at 4 months. In contrast, the highest expression of the controls (innervated muscles) were observed at 1 month. These changes in myogenin expression in denervated buccal muscles were consistent with the change in satellite cell proliferation and in muscle nucleic acid concentration.

CONCLUSION

Myogenin protein expression in longterm facial muscle denervation is closely associated with satellite cell regeneration. Myogenin may promote satellite cell differentiation, and therefore may improve the treatment of facial paralysis.

[Preliminary study on purification function of reed wetland for nutrients from land sources]

The preliminary study on purification function of reed wetland for nutrients from land sources were conducted by irrigation channels and lysimeters. The results show that the purification rates for N, P and CODcr are from 41.7%-64.71% in the channels and 60.0%-75.92% in the lysimeters. The contents of N and P reached the national second level standards of sea water after filtration by lysimeters. By harvest, the good recycle between wetland and land is formed without accumulation.

What determines severity among patients with painful functional bowel disorders?

OBJECTIVE

For patients with painful functional bowel disorders (FBD), physicians frequently make diagnostic and treatment decisions based on the severity of the pain reported; patients with severe painful complaints may receive extensive diagnostic tests and treatments. Therefore, it would be important to determine what clinical factors contribute to the judgment of severity among patients with FBD. The aim of this study was to identify the psychosocial, behavioral, and physiological (visceral sensitivity) factors that predicted severity in patients with moderate to severe FBD.

METHODS

Two hundred eleven female patients with moderate or severe FBD, as determined by the Functional Bowel Disorder Severity Index, entered a multicenter treatment trial at the University of North Carolina and the University of Toronto. Patients filled out diary cards and were given questionnaires and physiological testing (rectal sensitivity using barostat). Analysis of covariance and logistic regression adjusting for demographic factors were performed to determine which factors distinguished patients at study entry with moderate from those with severe FBD.

RESULTS

Patients with severe FBD were characterized by greater depression and psychological distress, poorer physical functioning and health-related quality of life, more maladaptive coping strategies, and greater health care utilization. There was a trend for patients with severe FBD to have lower rectal sensation thresholds. Regression analysis indicated that severity was best predicted by behavioral features: poorer daily physical function, difficulties related to eating, more phone calls to the physician, and more days in bed for GI symptoms.

CONCLUSIONS

We conclude that patient illness behaviors are best correlated with severity in FBD. The use of psychopharmacological agents (e.g., antidepressants) and psychological treatments to treat psychiatric comorbidity and to improve behavioral coping styles is recommended. Training to help medical physicians identify and respond to psychosocial and behavioral features of these conditions is likely to improve patient satisfaction with their care and the clinical outcome.

[Spectroscopic study on DL-homocysteic acid and it's complexes]

The main IR bands of the DL-Homocysteic acid was preliminary assigned. The complexes of DL-Homocysteic acid with Na+, K+, Ca2+ were synthesized. Element analysis and TGA-DTA were used to conclude the compositions of these complexes. The FTIR and FT-Raman spectra were studied to distinguish the different coordination structures. The bands of carboxyl, sulfonate and amino groups are all shifted. The peaks of-CH2- also changed a lot. The results indicated that the H-bonding structures among the moleculars were rearranged. The carboxyl and sulfonate groups of DLH both coordinated with the metal ions. And the coordination structure of C=O group in the three complexes were all monodentated.

Further validation of the IBS-QOL: a disease-specific quality-of-life questionnaire

OBJECTIVE

There has been growing interest in the investigation of health-related quality of life (HRQOL) among patients with gastrointestinal (GI) disorders. We recently reported on the development and preliminary validation of the IBS-QOL, a specific quality-of-life measure for irritable bowel syndrome (IBS). The aim of this study was to determine the longitudinal construct validity (responsiveness) of the IBS-QOL.

METHODS

Female patients enrolled in a multicenter treatment trial for functional bowel disorders were studied pre- and posttreatment with the IBS-QOL and other health status measures. Based on the response to treatment for several variables (pain/14-day score, daily function, and days in bed/3 months), patients were stratified into Responders, Partial Responders, and Nonresponders. Change scores in the IBS-QOL were then statistically compared with changes in the other variables to determine their correlation and whether Responders were significantly different from non- and Partial Responders on the IBS-QOL.

RESULTS

There was a significant correlation between change scores on the IBS-QOL and the other measures of treatment effect (Pain/14 days, r = 0.25, p < 0.002; Sickness Impact Profile [SIP] Total Score, r = 0.28, p < 0.0004). In addition, the IBS-QOL scores significantly differentiated Responders from Nonresponders for most of the variables tested (regression trend test for Pain/14 days, p < 0.04; SIP Total, p < 0.0001; SIP Physical, p < 0.0001; SIP Psychosocial, p < 0.002, and SIP Eating, p < 0.04).

CONCLUSION

The IBS-QOL is responsive to treatment in a referral-based clinical population of patients with functional bowel disorders.

Preliminary investigation of sequence-independent DNA binding proteins in rat skeletal muscle sarcoplasmic reticulum and their function

To observe the binding of plasmid DNA to non-nuclear DNA binding proteins in sarcoplasmic reticulum (SR) and the effects of this binding on SR function, sarcoplasmic reticulum proteins in rat skeletal muscle were isolated by differential centrifuge and sucrose density-gradient centrifuge. The results showed that there are two sequence-independent DNA binding proteins in SR proteins, the molecular weights of which are 83 and 58 ku, respectively. Ca(2+) uptake and release of SR were remarkably promoted by the binding of plasmid DNA to DNA binding proteins in SR, the mechanism is probably through increasing of Ca(2+)-ATPase activity in SR and changing of character of Ca(2+) release channel ryanodine receptors induced by the binding. These results suggest that there exist DNA binding proteins in SR and its binding to DNA may affect Ca(2+) transport of SR.

Further validation of the IBS-QOL: a disease-specific quality-of-life questionnaire

OBJECTIVE

There has been growing interest in the investigation of health-related quality of life (HRQOL) among patients with gastrointestinal (GI) disorders. We recently reported on the development and preliminary validation of the IBS-QOL, a specific quality-of-life measure for irritable bowel syndrome (IBS). The aim of this study was to determine the longitudinal construct validity (responsiveness) of the IBS-QOL.

METHODS

Female patients enrolled in a multicenter treatment trial for functional bowel disorders were studied pre- and posttreatment with the IBS-QOL and other health status measures. Based on the response to treatment for several variables (pain/14-day score, daily function, and days in bed/3 months), patients were stratified into Responders, Partial Responders, and Nonresponders. Change scores in the IBS-QOL were then statistically compared with changes in the other variables to determine their correlation and whether Responders were significantly different from non- and Partial Responders on the IBS-QOL.

RESULTS

There was a significant correlation between change scores on the IBS-QOL and the other measures of treatment effect (Pain/14 days, r = 0.25, p < 0.002; Sickness Impact Profile [SIP] Total Score, r = 0.28, p < 0.0004). In addition, the IBS-QOL scores significantly differentiated Responders from Nonresponders for most of the variables tested (regression trend test for Pain/14 days, p < 0.04; SIP Total, p < 0.0001; SIP Physical, p < 0.0001; SIP Psychosocial, p < 0.002, and SIP Eating, p < 0.04).

CONCLUSION

The IBS-QOL is responsive to treatment in a referral-based clinical population of patients with functional bowel disorders.

[Effect on keratocyte-mediated collagen degradation by Pseudomonas aeruginosa]

OBJECTIVE

To study the pathogenesis of cornea melting (ulceration) by pseudomona (P) aeruginosa for instruction of clinical treatment.

METHODS

Type I collagen gels with or without suspended keratocytes were incubated for 24 hours under medium containing sterile P. aeruginosa culture broth. Native collagen fibrils were removed from the media by ultrafiltration. The ultrafiltrates were then hydrolyzed, and the amount of hydroxyproline was measured spectrophotometrically. The effect of a synthetic matrix metalloproteinase (MMP) inhibitor, Galardin, on collagen degradation was also examined.

RESULTS

P. aeruginosa broth induced type I collagen gel degradation directly. In the presence of keratocytes, degradation by P. aeruginosa broth was enhanced. Galardin significantly reduced the amount of collagen degraded by P. aeruginosa culture broth, no matter keratocytes were present or not.

CONCLUSION

P. aeruginosa culture broth directly degrades type I collagen and also increases keratocyte-mediated collagen degradation. The result is helpful to the clinical treatment of cornea melting caused by P. aeruginosa, and the mechanism should be further studied.

Isolation and mapping of rFUS6, a rice orthologue of Arabidopsis thaliana FUS6

COP9 complex is one of the most important components that act in repressing photomorphogenesis in Arabidopsis thaliana. FUS6 has been identified as one of eight subunits of the COP9 complex in Arabidopsis. Using Arabidopsis Fus6 cDNA as a probe, we screened a rice root cDNA library and a rice genomic library. A 1730-bp cDNA was obtained, which has an open reading frame corresponding to 441-amino-acid. This 441 amino acids putative protein has 67% identity with Arabidopsis COP11/FUS6 (AtFUS6) and 40% identity with human GPS1, an AtFUS6 orthologue. So we designated this novel gene as rFUS6. The 6.2-kb genomic sequence of rFUS6 was also obtained. Sequence comparison showed that the rFUS6 gene had six exons and five introns. Sequence inspection of the 5'-flanking region revealed the presence of some potential light-regulated cis-elements such as a G-box, GT-1 binding sites, and a TGACG motif. Southern hybridization with rice total DNA showed that rFUS6 was perhaps a single copy gene. The rFUS6 locus was mapped by hybridization with a rice BAC library membrane and the results showed that rFUS6 had a locus at 16.3 cM of chromosome 1.

[In vitro proliferation and differentiation of bone marrow stem cells of aplastic anemia patients]

OBJECTIVE

To investigate the quality of bone marrow stem cells from aplastic anemia patients and their in vitro responses to hemopoietic growth factors(HGF).

METHODS

CD34 positive bone marrow cells from 10 chronic aplastic anemia(CAA), 5 severe aplastic anemia(SAA) patients and 5 healthy subjects were detected with immunoflurescence assay, enriched by Panning way, and then cultured in vitro for CFU-GM, BFU-E and CFU-E in the presence of recombinant HGFs.

RESULTS

CD34 positive rates of the bone marrow mononuclear cells(MNC) of CAA, SAA and control groups were (1.05 +/- 0.51)%, (0.70 +/- 0.37)% and (1.27 +/- 0.45)%, respectively, and there was no difference among them (P > 0.05). After being enriched, CD34 positive cells in MNC of CAA, SAA and control groups increased to a similar level(P > 0.05). In the presence of G-CSF or GM-CSF, the enriched CD34 positive MNC of CAA and SAA patients formed similar CFU-GM number to those of normal controls. The numbers of BFU-E and CFU-E formed from the enriched CD34 positive MNC of CAA and SAA patients were also the same as that of normal control groups under the stimulation of erythropoietin and interleukin-3. Stem cell factor could cooperate with G-CSF, GM-CSF, and erythropoietin significantly increasing the numbers of CFU-GM, BFU-E and CFU-E of CAA, SAA and normal control's enriched CD34 positive MNC.

CONCLUSION

The bone marrow CD34 positive cells from aplastic anemia patients appears to be normal in percentages and in in vitro proliferation/differentiation capacities.

Quantitative association between a newly identified molecular variant in the endothelin-2 gene and human essential hypertension

BACKGROUND

Essential hypertension is a multifactorial disease in which the genetic contribution is probably the result of a number of genes acting in combination. Recent work has incriminated endothelin-2 (ET2) as a candidate gene for human essential hypertension. This study sought to (i) determine the existence of any molecular variants in the ET2 gene; (ii) undertake an allelic-association study of any such variants found in a large group of well characterized hypertensive and control populations; and (iii) assess any quantitative relationship between the molecular variant and pretreatment blood presure.

METHODS

The ET2 gene was subjected to single strand conformation polymorphism (SSCP) analysis in order to identify novel molecular variants. Well-characterized subjects recruited from our local population were used in our association study. Two hundred and forty-four hypertensive patients with pre-treatment blood pressure (range 139/94-237/133 mmHg) were well matched with 228 controls from our local population of 30000 healthy subjects (range 96/62-160/85 mmHg). All subjects were Caucasian.

RESULTS

Polymerase chain reaction-SSCP identified a single A985G base change in 3'-UTR of the ET2 gene which was confirmed by direct sequencing. A restriction site for the enzyme BsmA1 was either created (+) or removed (-) with this polymorphism. Analysis of variance showed that the ET2 genotype was an independent predictor of pre-treatment diastolic blood pressure (DBP) in the hypertensive (P< 0.001) but not normotensive group with higher pressures tracking with the (-) allele. Other covariates such as age, sex, alcohol, cigarette smoking, body mass index and cholesterol showed no significant relationship with this genotype. The genotype frequencies for the hypertensive and control population were (-/-: -/+: +/+) 178 :58:8 and 168:55: 5, respectively (not significant). Subjects from the top and tail quartiles of measurement of blood pressure in both groups were selected for genotype and allele frequency comparison. Both genotype and allele differences were highly significant between the two extreme groups for DBP (genotype P< 0.001, alleles P< 0.01) distribution. A search for potential functional variants in linkage disequilibrium with A985G found one further variant in the 5'-UTR, C44T. Conditional haplotype probabilities in 214 chromosomes show that this polymorphism is not in linkage disequilibrium with the 3'-UTR. No other variants were found on a molecular screen of the transcribed portion of the ET2 gene.

CONCLUSION

This newly identified polymorphism of the ET2 gene tracked significantly in hypertensives when blood pressure was assessed as a quantitative trait. The difference in genotype and allele frequencies between the extremes of blood pressure suggest that the ET2 locus influences the severity rather than the initial development of hypertension.

A study of platelet organelles and membrane glycoprotein in patients with Binswanger's disease

OBJECTIVE

To discuss the possible role of platelets in Binswanger's disease by studying the changes of organelles and membrane glycoprotein in platelets.

METHODS

The organelles (dense bodies, alpha granules, and mitochondria) within platelets were measured with transmission electron microscopy in 25 patients with Binswanger's disease and matched controls, while alpha granule membrane glycoprotein CD62 and lysosomal integral membrane glycoprotein CD63 on platelet membrane were analyzed by flow cytometry.

RESULTS

The percentage of CD62-positive platelets was 3.6% +/- 2.1% and 5.7% +/- 2.4% in controls and in patients, respectively (P < 0.01). The percentage of CD63 expression platelets was 3.1% +/- 2.2% and 3.2% +/- 2.3% in controls and patients, respectively (P > 0.05). When compared with controls, platelets of patients contained fewer alpha granules (P < 0.01), and had no changes in dense bodies and mitochondria (P > 0.05). CD62 levels were different among patients with regarding to the degree of white matter low attenuation.

CONCLUSION

There is selective degranuation of platelets in patients with Binswanger's disease and the abnormalities of platelet secretion may play a role in the pathophysiology of this illness.

Morphine applied to the thalamic nucleus submedius produces a naloxone reversible antinociceptive effect in the rat

Our previous studies have indicated that the thalamic nucleus submedius (Sm) is involved in nociceptive modulation and plays an important role in an endogenous analgesic system (a feedback loop) consisting of spinal cord - Sm - ventrolateral orbital cortex (VLO) - periaqueductal gray (PAG) - spinal cord. To further investigate the neurotransmitter and receptor mechanisms in this nociceptive modulatory pathway, we tested the effects of microinjection of morphine and naloxone into the Sm on the rat tail flick (TF) reflex. A unilateral microinjection of morphine (8.0 mM, 0.5 microl) into the Sm significantly depressed the TF reflex, whereas a unilateral microinjection of naloxone (5.0 mM, 0.5 microl) into the Sm facilitated the TF reflex. Five minutes after morphine application into Sm, injection of naloxone in this nucleus markedly reversed the inhibition evoked by applying morphine in Sm. These findings suggest that the endogenous opioid peptides may be involved in the antinociceptive effects evoked by activation of the Sm-VLO-PAG pathway which depressed the nociceptive inputs at the spinal level via the brainstem descending inhibitory system, and exert a tonic descending influence.

Metabotropic glutamate receptors in superficial laminae of the rat dorsal horn

Light and electron microscopic immunocytochemistry were employed here to show the distribution of metabotropic glutamate receptors (mGluRs) mGluR2/3 and mGluR5 in laminae I and II of the dorsal horn, to identify their pre- and postsynaptic location, and to test colocalization with gamma-aminobutyric acid (GABA). mGluR2/3 was mainly in the inner part of lamina II; mGluR5 was mainly in laminae I and II. Electron microscopy showed that both mGluR2/3 and mGluR5 were in perikarya, dendrites, and vesicle-containing profiles. Two main morphological types of primary afferent terminals can be distinguished in the superficial laminae: C1, likely to be endings of unmyelinated fibers, and C2, of small myelinated fibers. Quantitative data show that only a small fraction of C2s stained for either receptor; more common were immunopositive dendrites postsynaptic to these terminals, and most common were appositions between C2s and mGluR5 immunopositive dendrites. Vesicle-containing profiles were characteristically apposed to primary afferent terminals, mainly C2s. Immunopositivity for mGluRs, especially mGluR2/3, was present in vesicle-containing profiles apposed to C2, none to C1, and about half of the profiles immunostained for either receptor were also stained for GABA. The presence of presynaptic and postsynaptic mGluRs in both inhibitory and excitatory interneurons may contribute to complex processing of fast and slow responses to peripheral input in superficial laminae. As selective agonists of mGluRs may modulate GABA release, the present demonstration of mGluRs in GABAergic terminals of presumed interneurons suggests that facilitatory effects may involve a mechanism of disinhibition.

Electrically-evoked inhibitory effects of the nucleus submedius on the jaw-opening reflex are mediated by ventrolateral orbital cortex and periaqueductal gray matter in the rat

In previous studies we have shown that electrical stimulation of the nucleus submedius inhibits the rat radiant heat-induced tail flick reflex, and that this antinociceptive effect is mediated by the ventrolateral orbital cortex and periaqueductal gray. The aim of the present study was to examine whether electrical stimulation of the nucleus submedius could inhibit the rat jaw-opening reflex, and to determine whether electrolytic lesions of the ventrolateral orbital cortex or the periaqueductal gray could attenuate the nucleus submedius-evoked inhibition. Experiments were performed on pentobarbital-anesthetized rats. The jaw-opening reflex elicited by electrical stimulation of the tooth pulp or the facial skin was monitored by recording the evoked digastric electromyogram. Conditioning stimulation was delivered unilaterally to the nucleus submedius 90 ms prior to each test stimulus to the tooth pulp. After that, electrolytic lesions were made in ventrolateral orbital cortex or periaqueductal gray, and the effect of nucleus submedius stimulation on the jaw-opening reflex was re-examined. Unilateral electrical stimulation of nucleus submedius was found to significantly depress the jaw-opening reflex (mean threshold of 28.0+/-1.4 microA, n = 48), and the magnitude of inhibition increased linearly when the stimulus intensity was increased from 20 to 70 microA, resulting in depression of the digastric electromyogram amplitude from 18.4+/-5.4% to 74.0+/-4.9% of the control (P < 0.01, n = 37). The onset of inhibition occured 60 ms after the beginning of nucleus submedius stimulation and lasted about 100 ms, as determined by varying the conditioning-test time interval. Furthermore, ipsilateral lesions of the ventrolateral orbital cortex or bilateral lesions of the lateral or ventrolateral parts of periaqueductal gray eliminated the nucleus submedius-evoked inhibition of the jaw-opening reflex. These data suggest that the nucleus submedius plays an important role in modulation of orofacial nociception, and provide further support for a hypothesis that the antinociceptive effect of nucleus submedius stimulation is mediated by ventrolateral orbital cortex and activation of a descending inhibitory system in the periaqueductal gray.

Association of the G(s)alpha gene with essential hypertension and response to beta-blockade

We examined whether the GNAS1 locus, encoding the G(s) protein alpha-subunit (G(s)alpha), is implicated in the genetic causes of essential hypertension. A common silent polymorphism (ATT-->ATC, Ile(131)) was identified in exon 5 of the G(s)alpha gene by single-strand conformation polymorphism analysis and DNA sequencing. This polymorphism consists of the presence (+) or absence (-) of a restriction site for FokI. Only 1 other rare allele was found in the coding region; the high GC content of the 5' noncoding sequence prevented mutation scanning of the promoter region of the gene. There was a significant difference in frequency of the FokI alleles between 268 white hypertensives (FokI+:FokI-, 51%:49%) and a matched group of 231 control subjects (FokI+:FokI-, 58%:42%) (P=0.02). Multiple regression analysis showed that the FokI genotype was independently related to the level of untreated systolic blood pressure in 294 well-characterized white hypertensives (P=0.01) but not in normotensives. The influence of the FokI allele on blood pressure (BP) response to beta-blockade was examined in 114 of the patients randomly assigned to this class of drug. Significant differences in frequency of the FokI allele were observed in the good responders (FokI+:FokI-, 62.5%:37.5%, n=36) versus the poor responders (FokI+:FokI-, 41.7%:58.3%, n=30) after beta-blocker therapy (P=0.02). In a multiple regression analysis, the G(s)alpha genotype was the only independent predictor of BP response. These results suggest that the GNAS1 locus might carry a functional variant that influences BP variation and response to beta-blockade in essential hypertension.

Leptin modulates the glucocorticoid-induced ovarian steroidogenesis

Leptin regulates food intake and other activities through its hypothalamic receptor. Leptin receptors are also found in other organs, including the ovary. Direct effects of leptin in ovarian steroid production were studied in primary rat granulosa cells and in rat and human granulosa cell lines. Leptin (0.6-18 nM) suppressed ovarian steroid synthesis costimulated by FSH and dexamethasone. Production of pregnenolone, progesterone, and 20alpha-hydroxy-4-pregnen-3-one was inhibited by leptin. This inhibition was due at least in part to reduced expression of adrenodoxin, a component of the P450scc system enzyme. Costimulation of progesterone production by forskolin and dexamethasone was also inhibited by leptin, whereas the forskolin-induced cAMP production was not affected. We find that leptin induces c-Jun expression and attenuates the transcriptional activity of the glucocorticoid receptor (GR) in granulosa cells. Elevation of c-Jun expression by other means, e.g. 12-O tetradecanoyl-phorbol-13-acetate or transfecting with a c-Jun expression vector, abolished the transcriptional activity of the GR. A leptin-induced elevation of c-Jun modulates the transcriptional activity of the GR, possibly leading to the observed attenuation of steroidogenesis. It was recently shown that glucocorticoids stimulate leptin expression in vivo, which in turn, inhibits cortisol synthesis. A direct action of leptin on the ovary is an additional element of a regulatory network that maintains the homeostasis of steroid production.

[Methodology of DNA fingerprinting and its application in identification of M. tuberculosis]

OBJECTIVE

To explore methodology of DNA fingerprinting technique and its application in identification of strains of M. tuberculosis.

METHODS

This research was based on different copy numbers and location of chromosome DNA IS6110 in M. tuberculosis genome. After DNA of M. tuberculosis were cut by endonuclease PvuII, the products were transferred to nylon membrane, then detected and hybridized by enhanced chemiluminescent (ECL) labeling techniques.

RESULTS

Fifty clinical isolates from different TB patients had unidentical DNA fingerprinting patterns. DNA fingerprinting patterns showed a great difference from sputum and pus specimens of the same patient. H(37) R(v) ofloxacin resistant and sensitive strains had an identical DNA fingerprinting pattern.

CONCLUSIONS

Identification of M. tuberculosis strains is feasible by DNA fingerprinting technique.

Inhibitory effects of 5-hydroxytryptamine microinjection into thalamic nucleus submedius on rat tail flick reflex are mediated by 5-HT2 receptors

Our previous findings indicated that electrical or chemical activation of the thalamic nucleus submedius (Sm) produced significant antinociceptive effects and that these effect were blocked by lesion or depression of the ventrolateral orbital cortex (VLO) or the periaqueductal gray (PAG) suggesting a role of the Sm in modulation of nociception. To further investigate the neurotransmitter mechanism involved in this nociceptive modulatory pathway, we tested the effects of microinjection of 5-hydroxytryptamine (5-HT, 50 mM, 0.5 microl) into Sm on the tail flick (TF) reflex. The results show that a unilateral microinjection of 5-HT into Sm significantly depresses the TF reflex; and that this effect is repeatable and dose-dependent. Furthermore, microinjection of 5-HT2 receptor antagonist cyproheptadine (CPT, 0.3 mM, 0.5 microl) into the same Sm site reverses this 5-HT-evoked inhibition of TF reflex. These results suggest that 5-HT application to the Sm may activate Sm neurons through the 5-HT2 receptors leading to activation of the brainstem descending inhibitory system via the VLO and depression of the nociceptive information at the spinal level.