Cocaine cardiotoxicity differs markedly in isolated hearts of two strains of rats exhibiting phenotypic differences in sensitivity to seizures

Isolated hearts from two strains of rats bred for sensitivity or resistance to amygdala kindling that also exhibit, in vivo, differential sensitivity to the cardiotoxicity of cocaine were studied. The goal was to determine if the differential cardiotoxic sensitivity was due, at least in part, to intrinsic strain-dependent differences in the heart. The Langendorff preparation was used (n=8 per strain). Hearts were perfused with increasing concentrations of cocaine (5 x 10(-6), 1 x 10(-5), 5 x 10(-5), 1 x 10(-4), and 5 x 10(-4) M) for 5 min with a 5 min washout between exposure to successive concentrations. Consistent with in vivo observations, hearts from genetically slow amygdala kindling rats (Slow) required lower cocaine doses to develop cardiac arrhythmias and arrest as compared to the hearts from genetically fast amygdala kindling rats (Fast). At 5 x 10(-5) M cocaine arrhythmias occurred in 38% (3/8) Slow and 0% Fast hearts. Five of 8 Slow hearts and none of 8 Fast hearts were arrested by 10(-4) M cocaine. Arrest in Fast hearts occurred only with 5 x 10(-4) M cocaine. Cocaine constricted coronary arteries (no significant difference between strains). On the other hand, coronary arteries of Slow but not Fast hearts dilated during cocaine washout after perfusion with all but the highest concentration of cocaine. We conclude that factors intrinsic to the heart and coronary artery influence the sensitivity or response of these structures to cocaine.

Neuronal apoptosis induced by HIV-1 Tat protein and TNF-alpha: potentiation of neurotoxicity mediated by oxidative stress and implications for HIV-1 dementia

Apoptosis of neurons and non-neuronal cells has been demonstrated in the brain of AIDS patients with dementia. Previous studies suggest that the apoptotic stimuli are likely to be soluble factors. Several candidates for the soluble factors that lead to neuronal apoptosis in HIV-1 infection have been proposed, including the HIV-1 Tat protein and TNF-alpha. The mechanisms that lead to neuronal apoptosis in the brain of AIDS patients in vivo, may involve the combined effects of more than one pro-apoptotic factor. In this study, we examine whether exposure of primary human neurons to the combination of HIV-1 Tat and TNF-alpha can potentiate the induction of neuronal apoptosis compared with exposure to either factor alone. TNF-alpha was shown to potentiate the induction of neuronal apoptosis by HIV-1 Tat via a mechanism that involves increased oxidative stress. Antioxidants inhibited, but did not completely abolish the induction of neuronal apoptosis by Tat, suggesting that other mechanisms are also likely to be involved. These findings suggest that soluble HIV-1 Tat and TNF-alpha may play a role in neuronal apoptosis induced by HIV-1 infection of the CNS, particularly when present in combination. Our findings further suggest that one mechanism whereby combinations of pro-apoptotic factors may potentiate the induction of neuronal apoptosis in the brain of AIDS patients is by increasing oxidative stress. Understanding the role of oxidative stress and other mechanisms that lead to apoptosis in HIV-1 infection of the CNS may advance the development of new therapeutic strategies to prevent neuronal cell death and improve neurologic function in AIDS patients.

[Treating portal hypertension by subtotal splenectomy with retroperitoneal splenic transposition and devascularization: clinical study]

OBJECTIVE

To devise a new surgical procedure for improving the operative effect of portal hypertension caused by hepatic cirrhosis.

METHOD

In treatment group, subtotal splenectomy with retroperitoneal transposition was performed in 36 patients of cirrhotic hypertensives. In control group, 36 patients were treated by devascularization. The follow-up period ranged from 3 months to 5.5 years (average 26 months).

RESULT

In the treatment group, the rates of disappearance, improvement and absence of changes of esophageal varices were 11.5%, 61.5% and 26.9%, respectively, and in the control group those of improvement were 50.0%, absence of change 45.8% and aggravation 4.2%. There was a significant difference between them (P < 0.05). In the treatment group, hypersplenism disappeared in all. There was also significant difference between the two groups in immunological indexes (P < 0.05). DSA showed abundant collateral circulation in the residual spleen and retroperitoneal wall, which enabled the portal blood flow diverting to retroperitoneal tissues.

CONCLUSION

This method possesses the advantages of devascularization and decompression shunt. It is of value in retaining part of spleen in surgical treatment of portal hypertension.

[Isoharringtonine induces apoptosis in human leukemia HL-60 cell]

Harringtonine (HT), homoharringtonine (HHT) and isoharringtonine (IHT) are cephalotaxine alkaloids with anticancer activities which were isolated from Cephalotaxus hainanensis indigenous to China. Since the 1970s, HT and HHT have been developed as effective anticancer drugs in China and have been used widely in the treatment of acute nonlymphoid leukemia and chronic granulocyte leukemia. Although IHT has the advantage of low toxicity, it has not been developed as an anticancer drug because of its very low content in the plant. The cell apoptosis induced by isoharringtonine was investigated in human acute promyelocytic leukemia HL-60 cells by agarose gel electrophoresis of DNA, flow cytometry and transmission electron microscopy. In these experiments IHT showed significant and rapid apoptotic inductive effect on HL-60 cells in both concentration- and time-dependent fashion. The characteristic apoptosis-related features could be seen in IHT treated HL-60 cells. Transmission electron microscopy of IHT treated HL-60 cells displayed chromatin condensation and aggregation under the nuclear membrane, nuclear fragmentation and apoptosis body formation. Typical DNA ladder in agarose gel electrophoresis and pre-G1 peak in flow cytometric analysis were also observed in the cells exposed to IHT. The apoptotic rate could reach 43.8% in the HL-60 cells treated for 120 minutes with IHT 10(-7) mol.L-1. The cytotoxicity of IHT paralleled with cell apoptosis indicating that the anticancer activity of IHT results from the induction of apoptosis. These results are important impetus for further research and development of IHT as an anticancer agent.

[The influence of implantal autograft bone in total cleft palate on maxillary growth an experiment study in dogs]

OBJECTIVE

To test the hypothesis that implant autograft bone in total cleft palate at primary cleft palate repair which may resists the disturbance of maxillary growth by cleft and denud bony wound.

METHODS

40 dogs were randomly divided into four groups: three control groups and one experimental group. The first control group was unoperated, the second group had a surgically created cleft plate, the third group also had a surgically created cleft palate. Using a two-flap procedure immidiately, the experiment group had a surgically created cleft palate, but the palate was recontracted by implanting a piece of autograft rib bone with two-flap repair. All animals were sacrificed on the 34th week after operation (43 weeks postnatal). Thirty-four metricranial variables were measured directy from the cleaned skulls.

RESULTS

The method is useful for maxillary growth and development by bone implant in total cleft palate, but it can cause maxillary deformity.

CONCLUSION

Clinical doctors should be cautious in using the method of primary-delay bone grafting in reparing total cleft of cleft palate.

Evidence for a role of bradykinin neurons in the control of gonadotropin-releasing hormone secretion

The present study provides evidence of a novel neuronal pathway for the control of GnRH secretion involving bradykinin neurons. Bradykinin neurons were shown by immunohistochemistry to be densely localized in several regions of the brain including the cortex, hippocampus and supraoptic nucleus, as well as two regions critical in the control of GnRH secretion, the organum vasculosum of the lamina terminalis and arcuate nucleus. Bradykinin dose-dependently stimulated GnRH release from male and proestrous female rat hypothalami in vitro. Antagonist studies revealed that bradykinin effects are mediated by the bradykinin B2 receptor. The effect of bradykinin on GnRH release is not mediated by the classical major transmitter, glutamate, as glutamate antagonists had no effect on bradykinin stimulation of GnRH release. Rather, bradykinin appears to act directly on the GnRH neuron as bradykinin stimulated GnRH release directly from immortalized GnRH (GT1-7) neurons in vitro, and immunoblot studies revealed that the bradykinin B2 receptor is present in GT1-7 neurons. The bradykinin B2 receptor was also demonstrated in the rat hypothalamus and pituitary by immunoblotting. Bradykinin-induced exocytosis of GnRH appears to involve activation of the PKC signaling pathway, as a PKC inhibitor blocked bradykinin-induced GnRH release. Finally, bradykinin neurons appear to be important mediators of steroid signals in the hypothalamus to produce the LH surge, as central administration of a B2 antagonist, but not a B antagonist, significantly attenuated the steroid-induced LH surge in the ovariectomized female rat.

[Study on urinary levels of interleukin-1 beta, interleukin-6 and tumor necrosis factor-alpha in patients with renal cell carcinoma]

We examined the preoperative and postoperative, urinary levels of the cytokines, interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) in 14 patients with renal cell carcinoma (RCC), and 9 patients who underwent nephrectomy as donors (controls). Although urinary IL-1 beta was measurable in every subject, both IL-6 and TNF-alpha were undetectable in 12 of the 14 patients. None of the urinary cytokines showed levels significantly different from the controls preoperatively. Urinary levels of IL-1 beta showed no correlation with clinical stage or histological grade. Only urinary IL-1 beta was significantly elevated after nephrectomy, when compared with the controls (P < 0.05). However, urinary IL-1 beta showed no correlation with operative blood loss or postoperative infection. These findings suggest that measurement of urinary cytokines is not useful for diagnosis or monitoring of therapy in RCC patients.

[Determination of copper, zinc, iron and calcium in wheat and maize and three nitrogen compounds in high and low risk areas of esophageal cancer]

This study reports the concentrations of copper, zinc, iron and calcium in wheat and maize from high risk area Linzhou and low risk area Yuzhou of esophageal cancer and three nitrogen compounds of four types of drinking water in Linzhou. The results showed that the concentrations of zinc and calcium in wheat and maize from Linzhou were significantly lower than these from Yuzhou, the copper concentrations in grains were higher and the iron in maize was lower. The nitrate-N concentrations in four types of drinking water from Linzhou were below the national standard but the nitrite and NH3-N concentrations were higher than the national limits. The results suggest that the low concentrations of zinc, iron and calcium and high concentrations of copper in grains as well as the high concentrations of nitrite and NH3-N may be related to the etiology of esophageal cancer.

Experimental studies of electroacupuncture on ventricular fibrillation threshold in rats with acute ischemic myocardium

By ligating the proximate left anterior descend (LAD) of coronary artery and inducing the ventricular fibrillation with electrical stimulation, the preventive effects of electroacupuncture (EA) on ventricular fibrillation were observed. The results showed that the ventricular fibrillation threshold (VFT) of rats with acute ischemic myocardium was raised after acupuncturing some acupoints, which could prevent the occurrence of ventricular fibrillation. Furthermore, the combination of EA and propranolol could enhance the VFT effectively, and they showed a good synergistic effect.

Localization of HIV-1 co-receptors CCR5 and CXCR4 in the brain of children with AIDS

The chemokine receptors CCR5 and CXCR4 are co-receptors together with CD4 for human immunodeficiency virus (HIV)-1 entry into target cells. Macrophage-tropic HIV-1 viruses use CCR5 as a co-receptor, whereas T-cell-line tropic viruses use CXCR4. HIV-1 infects the brain and causes a progressive encephalopathy in 20 to 30% of infected children and adults. Most of the HIV-1-infected cells in the brain are macrophages and microglia. We examined expression of CCR5 and CXCR4 in brain tissue from 20 pediatric acquired immune deficiency syndrome (AIDS) patients in relation to neuropathological consequences of HIV-1 infection. The overall frequency of CCR5-positive perivascular mononuclear cells and macrophages was increased in the brains of children with severe HIV-1 encephalitis (HIVE) compared with children with mild HIVE or non-AIDS controls, whereas the frequency of CXCR4-positive perivascular cells did not correlate with disease severity. CCR5- and CXCR4-positive macrophages and microglia were detected in inflammatory lesions in the brain of children with severe HIVE. In addition, CXCR4 was detected in a subpopulation of neurons in autopsy brain tissue and primary human brain cultures. Similar findings were demonstrated in the brain of adult AIDS patients and controls. These findings suggest that CCR5-positive mononuclear cells, macrophages, and microglia contribute to disease progression in the central nervous system of children and adults with AIDS by serving as targets for virus replication.

Intracellular calcium oscillations in cell populations of ras-transfected I-7 subline of human HaCaT keratinocytes

We have observed oscillations of intracellular Ca2+ (Ca[i]) concentration in populations of ras-transfected HaCaT keratinocytes of I-7 subline. In postconfluent monolayers of I-7 keratinocytes, an increase in extracellular Ca2+ (Ca[o]) concentration to 0.25-0.5 mM induced sinusoidal Ca(i) oscillations, which persisted longer than 1 h with amplitudes of 50-150 nM and periods of 5-10 min. Thapsigargin, which depletes internal Ca2+ stores, did not prevent Ca(o)-induced Ca(i) oscillations, and it also induced Ca(i) oscillations in the ras-transfected I-7 line. Removal of extracellular Ca2+ or addition of Ca2+-entry blocker La3+ or SK&F 96365 inhibited Ca(i) oscillations, suggesting that Ca(i) oscillations in ras-transfected HaCaT keratinocytes were dependent on Ca2+ influx across the plasma membrane. Because the Ca(o)-induced Ca(i) oscillations have been observed only in ras-transfected I-7 subline and not in its nontransfected parental HaCaT line, this may provide a partial explanation for the divergent responses of ras-transfected and nontransfected keratinocytes to Ca(o) signal for control of growth and differentiation.

Babesiasis in Nanjing area, China

This article discusses the tick-borne babesiases which harm dairy cattle, buffaloes and dogs. In addition, the pathogen, vector, seasonal occurrence, hosts, symptoms, pathological changes and treatment are summarized and analysed. The pathogens in this area were identified as Babesia bigemina, B. bovis and B. gibsoni; the vectors as Boophilus microplus, Rhipicephalus haemaphysaloides, Haemaphysalis longicornis. Affected buffaloes were found from April to September, peak numbers occurred between May and July. Affected dairy cattle were most numerous in July and August. Hunting dogs were the most affected dogs. Infected dogs were found from February until the beginning of December; peak numbers occurred from September to November. Affected animals were acute cases. Symptoms and pathological changes were obvious, but jaundice was rare in dogs. Acaprin, acriflavine, imidocarb and berenil were used early and late. Their effect was ideal but resistance has developed to these drugs.

[Inhibitory effect of samarium-153-labeled ethylenediaminetetramethylene phosphonate (EDTMP) on bone invasion and osteolysis in Walker 256 carcinoma bearing rats]

OBJECTIVE

To investigate the inhibitory effect of samarium-153 EDTMP on bone invasion and osteolysis in Walker 256 carcinoma bearing rats.

METHODS

Invasion and resorption of tibia by Walker 256 carcinoma in rats were evaluated by X-ray and histological examination.

RESULTS

Intravenous administration of 153Sm-EDTMP at a dose of 74 or 148 MBq/kg, the rat numbers with tibia invasion and bone resorption were reduced by fifty percent. 153Sm-EDTMP at a dose of 37 MBq/kg still exhibited inhibitory effect on bone invasion and osteolysis as compared with the control group. However, there was no indication of change in the weight of primary tumor even at the highest dose utilized.

CONCLUSION

Samarium-153 EDTMP can inhibit bone invasion and osteolysis by Walker 256 carcinoma in rats, but it has no effect on the growth of the transplanted tumor. Therefore, that the effect of 153Sm-EDTMP is due to a reduction in tumor growth leading to decreased bone invasion and osteolysis can be reasonably ruled out.

Tat protein induces self-perpetuating permissivity for productive HIV-1 infection

We report that human immunodeficiency virus type 1 (HIV-1) has evolved a self-perpetuating mechanism to actively generate cells permissive for productive and cytopathic infection. Only activated T cells can be productively infected, which leads to their rapid depletion (2 x 10(9)/day in an infected individual). Establishment of productive HIV-1 infection therefore requires continual activations from the large pool of quiescent T cells. Tat protein, which is secreted by infected cells, activated uninfected quiescent T cells in vitro and in vivo. These Tat-activated uninfected cells became highly permissive for productive HIV-1 infection. Activation of primary T cells by Tat protein involved integrin receptors and was associated with activation of mitogen-activated protein kinases, including ERK1 and JNK kinase. Accordingly, these primary T cells progressed from G0 to the late G1 phase of the cell cycle.

Bioavailability of selenium from veal, chicken, beef, pork, lamb, flounder, tuna, selenomethionine, and sodium selenite assessed in selenium-deficient rats

The bioavailability of selenium (Se) from veal, chicken, beef, pork, lamb, flounder, tuna, selenomethionine (SeMet), and sodium selenite was assessed in Se-deficient Fischer-344 rats. Se as veal, chicken, beef, pork, lamb, flounder, tuna, SeMet, and sodium selenite was added to torula yeast (TY) basal diets to comprise Se-inadequate (0.05 mg Se/kg) diets. Se as sodium selenite was added to a TY basal diet to comprise a Se-adequate (0.10 mg Se/kg), Se-control diet. The experimental diets were fed to weanling Fischer-344 rats that had been subjected to dietary Se depletion for 6 wk. After 9 wk of the dietary Se repletion, relative activity of liver glutathione peroxidase (GSHPx) from the different dietary groups compared with control rats (100%) was: flounder 106%, tuna 101%, pork 86%, sodium selenite 81%, SeMet 80%, beef 80%, chicken 77%, veal 77%, and lamb 58%. Se from flounder was the most efficient at restoring Se concentrations in the liver and skeletal muscle. Se from sodium selenite, SeMet, beef, veal, chicken, pork, lamb, and tuna was not dietarily sufficient to restore liver and muscle Se after 9 wk of recovery following a 6-wk period of Se depletion.

[Deviation of size-exclusion chromatographic behavior of tryptophan on TOYOPEARL HW-40S column]

A deviation of size-exclusion chromatographic behavior of amino acids on TOYOPEARL HW-40S column is reported. On the column 18 amino acids were not eluted in the same fraction in the total volume, but separated into 5 fractions with tryptophan as the last one far behind the total volume. Interaction between tryptophan and the matrices was investigated under different conditions in order to elucidate the chemical nature of the deviation. It was found that addition of trifluoroacetic acid and sodium chloride of high concentration in mobile phase, dramatically increased the retention time of trypophan, while addition of acetonitrile, sodium chloride of lower concentration and the hydrogen bond breaker urea reduced the interaction. It is concluded that adsorption of tryptophan on TOYOPEARL HW-40S is basically due to the hydrophobic nature with limited influence of hydrogen bond and ionic interaction. The former factor can be eliminated by keeping acentonitrile concentration over 50% (V/V), while the latter two can be reduced to the minimum by adding 0.17mol/L sodium chloride and 3.51mol/L urea. The results not only lead to better understanding of size-exclusion chromatography of this matrices, but also help to apply hydrophobic chromatography of this matrices to the isolation of amino acids and peptides.

[4-acetamidophenyl retinoate (4-APR) inhibits reconstituted basement membrane invasion by tumor cells and its mechanism]

OBJECTIVE

To study the inhibitory effect of new retinoid 4-acetamidophenyl retinoate (4-APR) on the reconstituted basement membrane invasion by B16-F10 mouse melanoma cells and its mechanism.

METHODS

Reconstituted basement membrane invasion assay was used to evaluate invasive ability of cancer cells. Type IV collagenase was assessed by PAGE substrate zymography. TIMP-1 mRNA expression of human nasopharyngeal carcinoma CNE-2Z cell line was measured by dot blot analysis. Cell growth curve assay was used to examine the growth inhibitory effect of 4-APR on B16-F10 cells.

RESULTS

4-APR, at the concentrations of 10(-5) mol/L and 10(-6) mol/L, suppressed the reconstituted basement membrane invasion of B16-F10 mouse melanoma cells by 54.2%, 41.9% and reduced type IV collagenase activities in the serum-free supernatant of CNE-2Z cells. In addition, 4-APR inhibited B16-F10 cell adherence to laminin, fibronectin and Matrigel, and induced CNE-2Z cell TIMP-1 mRNA expression.

CONCLUSION

Reconstituted basement membrane invasion of B16-F10 mouse melanoma cells was inhibited by 4-APR. The anti-invasion action of 4-APR might be associated with the suppression of tumor cell adhesion ability, the reduction of type IV collagenase activity in tumor cell culture supernatant and/or the induction of tumor cell TIMP-1 mRNA expression.

[An experimental study of the growth pattern and mechanisms of surgically induced cleft palate and palatoplasty on maxillary growth in dogs]

The authors observed the changing process of length, width and height of maxillary growth in experimental animals, the experimental animals were divided into the unoperated control group, the surgical induced cleft palate group, the repaired cleft palate group and the group of implanted autograft bone in total hard palate. The method of a serial dorsoventral and lateral cephalograms were used in the study. The experimental result showed: the rate of maxillary growth began to change from two to four weeks and finished in the eighteenth week after operation. There was a remarkable different rate of maxillary growth among the four groups. The track of premaxillary growth had a difference between unoperated control group and the others. The experimental result suggested that the direction of growth in nasal septal cartilage and the conduction of force from premaxillary to maxillary were inhibited. It is a main reason for maxillary growth disturbance of the cleft palate who had or had not surgery.

[An experimental study of the influence and mechanism of surgically induced cleft palate and palatoplasty on teeth and dental arch in dogs]

The dogs were selected as the experimental subjects in this study. The authors continuously observed the maxillary teeth and dental arch form in preoperation and 2, 4, 6, 10, 14, 18, 22, 26, 30, 34 weeks of post operation to all the animals. 40 puppies were divided into four groups, which were unoperated control group, surgically induced cleft palate group, cleft palate repaired group and cleft palate implanted bone group. The experimental result showed: there were remarkable differences at rate of itself growth between deciduous dentition and permanent dentition in the four groups. The result suggested that the cleft palate was a reason for disturbances of dental arch development, an exposed bone wound in hard palate of maxillary after palatoplasty was an important reason that it made maxillary dental arch growth problem heavier, authors could prevent the disturbs the transverse development of the maxillary dental arch from cleft palate who had or had not repaired by implanted bone in total cleft palate.

Modification of bupivacaine toxicity by nonselective versus neuronal nitric oxide synthesis inhibition

We have previously shown that pretreatment of rats with a nonselective nitric oxide synthase (NOS) inhibitor, N(omega)-nitro-L-arginine methyl ester (L-NAME), enhances the cardiovascular system (CVS) toxicity and reduces the central nervous system (CNS) toxicity of local anesthetics. This study was performed to differentiate the neuronal from the endothelial effects of L-NAME on the CNS and CVS toxicity of bupivacaine by comparing the effects of L-NAME with a neuronal selective NOS inhibitor, 7-nitroindazole (7-NI). Lightly anesthetized rats were premedicated for 30 min with L-NAME (2 mg kg(-1) x min(-1) intravenously [I.V.]), 7-NI (30 mg/kg intraperitoneally), or saline (control) then bupivacaine (2 mg x kg(-1) x min(-1)) was infused I.V. until asystole occurred. Bupivacaine doses required to produce seizures were the same among groups (saline = 10.1 +/- 2.6 mg/kg; L-NAME = 9.0 +/- 1.2 mg/kg; 7-NI = 10.2 +/- 1.0 mg/kg). However, plasma bupivacaine concentration (microg/mL) at seizure onset was significantly higher in animals pretreated with L-NAME (16.4 +/- 2.1) and, to a lesser degree, 7-NI (11.6 +/- 1.3) than that of control (9.7 +/- 1.6). Seizure duration and the number of epileptiform bursts were significantly reduced in L-NAME versus the other two groups. Doses for arrhythmias and asystole as well as plasma bupivacaine concentrations at arrhythmia onset were dramatically smaller in L-NAME-pretreated rats than in the other two groups. In summary, endothelial NOS inhibition dramatically alters both the CVS and CNS toxicity of bupivacaine with neuronal NOS inhibition playing a minor role.

A four-amino-acid insertion in the ligand-binding domain inactivates hRXRbeta and renders dominant negative activity

Retinoid X receptors (RXRs) are members of the steroid and thyroid hormone receptor superfamily of hormone-dependent transcription factors that mediate the pleiotropic effect of retinoids. Here, we report the initial characterization of an isoform of hRXR beta, termed hRXR beta3, which was previously identified as an H-2RIIBP isoform (Epplen and Epplen, 1992). The hRXR beta3 isoform cotains an in-frame insertion of four amino acids (SLSR) in the ligand binding domain at codon 419. The isoform is generated by alternate use of a 3' splice acceptor site and was detectable by reverse transcription polymerase chain reaction (RT-PCR) in all human tumor cell lines and mouse tissues examined. Chimeric receptors, in which the ligand-binding domain of hRXR alpha was substituted by the corresponding domain from hRXR beta3, were used to investigate the consequences of the SLSR insertion on the transactivation and DNA-binding functions of the chimeric receptor. Co-transfection assays revealed that a chimera RXR alpha/beta3 receptor failed to transactivate the RXR-specific CRBPII promoter, whereas the identical chimera lacking the SLSR insertion was active. The RXR alpha/beta3 receptor exhibited dominant negative activity against active retinoid X and retinoic acid receptors on retinoid-responsive promoters. Moreover, the RXR alpha/beta3 protein failed to interact physically with the retinoic acid receptor (RAR) to form heterodimers as detected by physical association assays, and failed to bind DNA containing an RAR-responsive element. Therefore, this suggests that the SLSR insertion in the ligand-binding domain of the RXR alpha/beta3 receptor is responsible for the altered behavior of the chimera. Our findings raise the possibility that RXR alpha/beta3, and perhaps hRXR beta3 isoform, function by titrating a limiting adaptor molecule that is involved in mediating retinoid function.

Two novel subgenomic RNAs derived from RNA 3 of tomato aspermy cucumovirus

Two abundant subgenomic RNAs, designated RNA 3B and RNA 5, were found to be associated with the V strain of tomato aspermy cucumovirus (V-TAV). Sequence determination showed that the 3'-terminal 323 nucleotides (nt) of RNA 3B was identical to RNA 5, whereas its 5'-terminal 163 nt was a direct repeat (one nt difference) of the 5'-half of RNA 5, and that both RNAs are completely homologous to the 3'-terminal untranslated region of TAV RNA 3. TAV RNAs 3B and 5 were also detected in the infection of a pseudorecombinant virus consisting of TAV RNA 3 and RNAs 1 and 2 from cucumber mosaic virus. Furthermore, only RNA 5, not RNA 3B, was detected in a TAV mutant in which one of the repeats was deleted from RNA 3. These genetic studies clearly show that both RNA species are derived from TAV RNA 3. However, in contrast to TAV RNAs 4 and 4A, which encode coat protein and 2b protein, respectively, RNAs 3B and 5 represent a novel class of subgenomic RNAs from TAV that do not function as mRNAs. Possible functional roles for such a class of viral subgenomic RNAs are discussed.

[Qualitative grading of detrusor contractility in benign prostatic hyperplasia patients]

To grade qualitatively detrusor contractility in benign prostatic hyperplasia (BPH), we studied 120 BPH patients aged from 58 to 89 years. The pressure-flow studies were performed. The passive urethral resistance relation (PURR) and Schäfer diagram were used to analyse the results. The detrusor contractility was divided into 4 classes: very weak (VW), weak (W), normal (N), and strong (ST). The types of pressure-flow were high pressure--low flow (HP-LF), high pressure--high flow (HP-HF), low pressure--low flow (LP-LF) and low pressure--high flow (LP-HF) type. The results showed that the incidence of VW, W, N and ST class was 12.5%, 26.7%, 47.5% and 13.3% respectively; the incidence of HP-LF, HP-HF and LP-LF type was 55%, 1.7% and 43.3% respectively. The weak detrusor strength could become powerful by the surgery treatment of bladder outflow obstruction (BOO) and the function training of detrusor. The detrusor strength class of a BPH patient was improved from W before surgery to N after surgery in our studies. The principles of the fluid dynamics and urodynamic and the clinical application of the qualitative grading of detrusor contractility were discussed.