[Characteristics of PD-L1 expression in tumor cells and tumor microenvironment of DLBCL with MYD88 L265P mutation]

Objective: To study the effect of MYD88 L265P mutation on the expression of PD-L1 in tumor cells and tumor microenvironment in diffuse large B-cell lymphoma (DLBCL), and to provide theoretical basis for immunotherapy for patients. Methods: Multiplex ligation-dependent probe amplification (MLPA) was used to detect the frequency of MYD88 L265P mutation in 72 cases of DLBCL diagnosed by pathologists in Cancer Hospital of Chinese Academy of Medical Sciences from August 2008 to May 2010. Expression of PD-L1 in tumor cells and tumor microenvironment in all samples was evaluated using PD-L1 (22C3) and PD-L1 (SP142) with Ventana automatic immunohistochemical (IHC) platform. The relationship between MYD88 L265P mutation and the expression of PD-L1 in DLBCL tumor cells and tumor microenvironment was assessed. Results: Of the 72 cases of DLBCL, MYD88 L265P mutation was detected in 15 (20.8%) cases. Nine cases with JAK2 amplification were excluded, and the remaining 63 cases of DLBCL were divided into MYD88 L265P mutant group (n=14) and MYD88 L265P wild-type group (n=49). IHC results showed that among the 14 cases of MYD88 L265P mutant groups, PD-L1 (22C3) was positive in 7 cases (7/14) of tumor cells and PD-L1 (SP142) was positive in 4 cases (4/14) of tumor microenvironment. Among the 49 cases of MYD88 L265P wild-type group, 9 cases (18.4%) were positive for PD-L1 (22C3) in tumor cells, and 38 cases (77.6%) were positive for PD-L1(SP142) in tumor microenvironment. In addition, among the 16 cases with PD-L1(22C3) expression in tumor cells, only 2 of the 7 cases with MYD88 L265P mutation were positive for PD-L1 (SP142) in tumor microenvironment. All 9 cases with wild-type MYD88 L265P were positive for PD-L1 (SP142) in tumor microenvironment. Statistical analysis showed that the expression level of PD-L1 (22C3) in tumor cells in the MYD88 L265P mutant group was significantly higher than that in the MYD88 L265P wild-type group (P=0.017). The expression level of PD-L1 (SP142) in tumor microenvironment in the MYD88 L265P mutant group was significantly lower than that in the MYD88 L265P wild-type group (P=0.001). Conclusions: MYD88 L265P mutation may play an important role in the regulation of PD-L1 expression in DLBCL tumor cells and tumor microenvironment. Further studies will provide a theoretical basis for immunotherapy of DLBCL patients with MYD88 L265P mutation.

[Expressions and clinical significances of paired box gene 2 and cyclin D1 in advanced ovarian serous carcinoma]

Objective: To investigate the expressions and clinical significances of paired box gene 2 (Pax2) and cyclin D1 protein in advanced ovarian serous carcinoma. Methods: From January 2003 to December 2013, the pathologic tissues of 202 patients with advanced ovarian serous cancer (Ⅲ-Ⅳ) who underwent initial cytoreductive surgery were collected. The expressions of Pax2 and cyclin D1 protein were detected by immunohistochemistry in tissue microarray. The relationships of their expressions with the clinicopathological features and prognosis of the patients were analyzed. Results: The positive rate of Pax2 protein expression of the 202 patients with ovarian serous adenocarcinoma was 24.8% (50/202) and that of cyclin D1 was 25.2% (51/202). The expressions of Pax2 and cyclin D1 were not significantly related with age, clinical stage and pathological grade of ovarian serous adenocarcinoma patients (P>0.05). The median overall survival (OS) time of Pax2-negative patients was 53 months and the progression-free survival (PFS) time was 29 months. The median OS time of Pax2-positive patients was 66 months and PFS time was 33 months, the OS of Pax2-negative patients was significant different from that of Pax2-positive patients (χ(2)=4.06, P=0.04). The median PFS time of Pax2-negative patients was not significant different from that of Pax2-positive patients (χ(2)=2.43, P=0.11). The median OS time of cyclin D1-negative patients was 62 months and PFS time was 30 months. The median OS time of cyclin D1-positive patients was 48 months and PFS time was 22 months. The median OS time of cyclin D1-negative patients was significantly different from that of cyclin D1-positive patients (χ(2)=4.71, P=0.03), while the median PFS time of cyclin D1-negative patients was marginally different from that of cyclin D1-positive patients (χ(2)=0.59, P=0.41). Multivariate analysis showed that the expression of Pax2 was an independent factor of the prognosis for patients with ovarian serous adenocarcinoma (RR=0.597, 95% CI 0.371-0.962, P<0.034). Conclusion: The expressions of Pax2 and cyclin D1 are associated with the prognosis of patients with advanced ovarian serous adenocarcinoma while Pax2 is an independent prognostic factor.

[Progress in diagnosis and treatment of radioactive iodine-refractory differentiated thyroid carcinoma]

The radioactive iodine-refractory differentiated thyroid carcinoma (RIR-DTC) is a complex process that involves multiple genetic changes and multiple signaling pathways.Radionuclide imaging, genomics and proteomics are effective to clarify the mechanism and helpful in clinical diagnosis and therapy.The treatment of RIR-DTC includes the removal of distant metastases, drug therapy, external radiotherapy and radiofrequency ablation.This review mainly focuses on the pathogenesis, diagnosis and treatment of RIR-DTC.

[Comparison of paired box genes 8 and 2 expression in epithelium tissues and the related tumors]

Objective: To explore the expressional differences between paired box genes 2(Pax2) and 8 (Pax8) protein in different kinds of epitheliums and tumors, and to investigate the clinicopathologic significance. Methods: Expression levels of Pax2 and Pax8 protein were detected in 75 cases of different human epithelium tissues and 255 cases of different tumors on tissue microarray by immunohistochemistry. Results: Pax2 and Pax8 selectively expressed in different tissues. The positive rates of Pax8 protein expressed in the normal epithelium of the thyroid, urinary system and female reproductive system were 100% (2/2), 60.0% (3/5) and 76.9% (10/13), respectively. The positive rates of Pax2 expressed in the epithelium tissues of urinary system and the female reproductive system were 40.0% (2/5) and 38.5% (5/13) respectively. However, the expression of Pax2 protein was not detected in the normal thyroid epithelium. The positive rate of Pax8 protein expressing in the epithelium of reproductive system was significantly higher than that of Pax2 protein (P<0.05). The tumors derived from different tissues also expressed different levels of protein Pax2 and Pax8. The positive rates of Pax8 in renal cell carcinoma, thyroid carcinoma and endometrial adenocarcinoma were 65.2% (15/23), 66.7% (10/15) and 80.0% (4/5), respectively. The positive rates of Pax2 in renal cell carcinoma, thyroid carcinoma and endometrial adenocarcinoma were 34.8% (8/23), 13.3% (2/15) and 20.0% (1/5), respectively. The positive rates of Pax8 protein expressed in renal cell carcinoma, thyroid carcinoma and endometrial adenocarcinoma were significantly higher than those of Pax2 protein (P<0.05). The positive rates of Pax8 in ovarian serous carcinoma, endometrial carcinoma and clear cell carcinoma were 92.9% (26/28), 81.8% (9/11) and 82.4% (14/17), respectively. The positive rates of Pax2 in ovarian serous carcinoma, endometrial carcinoma and clear cell carcinoma were 28.6% (8/28), 9.1% (1/11) and 17.6% (3/17), respectively. The positive rates of Pax8 protein expressed in ovarian serous carcinoma, endometrial carcinoma and clear cell carcinomawere significantly higher than those of Pax2 protein (P<0.05). Conclusions: Pax2 and Pax8 are specifically expressed in female reproductive system and uritany system. However, the positive expression of Pax8 is superior to that of Pax2. The combined expression of Pax8 and Pax2 can be used in the differential diagnosis of epithelial tumors derived from different origins.

Microwave irradiation is a useful tool for improving isolation of actinomycetes from soil

Actinomycetes are an important source of novel, biologically active compounds. New methods need to be developed for isolating previously unknown actinomycetes from soil. The objective of this experiment was to study microwave irradiation of soil as a means for isolating previously unknown actinomycetes. Soil samples were collected at ten elevations between 800 and 3670 m on Taibai Mountain, Shaanxi Province, China. Moistened soil samples were irradiated at 120 W heating power (2450 MHz) for 3 min using a household microwave oven. Irradiation increased total actinomycete, streptomycete, and antagonistic actinomycete counts on three types of culture media. Irradiation also increased the number of culturable actinomycete isolates. Some actinomycete isolates were culturable only after the soil was irradiated, whereas other isolates could not be cultured after irradiation. Irradiation of soil from elevations > 3000 m increased actinomycete counts significantly but had little effect on the number of culturable actinomycete isolates. In contrast, irradiation of samples from elevations < 3000 m had relatively little effect on actinomycete counts, but significantly increased the number of culturable actinomycete isolates. We used 16S rDNA sequence analysis to identify 14 actinomycete isolates that were only culturable after irradiation. Microwave irradiation of soil was helpful for isolating Streptomyces spp., Nocardia spp., Streptosporangium spp., and Lentzea spp. Slightly more than 90% of the identified actinomycete species were biologically active. In conclusion, microwave irradiation is a useful tool for isolating biologically active actinomycetes from soil.

Social rhythm regularity and the onset of affective episodes in bipolar spectrum individuals

OBJECTIVES

Research suggests that bipolar disorder individuals may have less social rhythm regularity than normal controls and that this may contribute to their affective symptoms and episodes. This study examined whether regularity prospectively predicted time to onset of major depressive, hypomanic and manic episodes in a sample with bipolar spectrum disorders.

METHODS

We recruited 414 undergraduate students from Temple University and University of Wisconsin diagnosed with cyclothymia, bipolar II disorder, or with no affective disorder (normal controls). Participants completed the Social Rhythm Metric at Time 1 and structured interviews approximately every four months for an average follow-up period of 33 months.

RESULTS

Participants diagnosed with cyclothymia and bipolar II disorder reported significantly fewer regular activities than normal controls, and approximately half of these participants experienced a worsening course of their illness over the study duration. Survival analyses indicated that both diagnosis and social rhythm regularity significantly predicted the time to participants' first prospective onset of major depressive, hypomanic and manic episodes.

CONCLUSION

Consistent with the social zeitgeber theory, bipolar spectrum participants reported less social rhythm regularity than normal controls, which prospectively predicted the survival time to affective episodes.

Mycobacterium avium complex-associated hemophagocytic syndrome in systemic lupus erythematosus patient: report of one case

Hemophagocytic syndrome (HPS) in systemic lupus erythematosus(SLE) patients has not commonly been reported. In this case study, we report the first case of Mycobacterium avium complex (MAC)-associated hemophagocytic syndrome in a patient with systemic lupus erythematosus (SLE). This SLE patient, a 15-year-old girl, had been on a high dose of prednisolone (> 0.5mg/kg/day) for more than 3 years. She presented with a spiking fever, hepatosplenomegaly, pancytopenia, hyperferritinemia and adult respiratory distress syndrome. Bone marrow examination revealed hemophagocytosis as well as non-caseating granulomatosis. There was no indication of SLE fare-up. She responded poorly to initial treatment with methyl-prednisolone, intravenous immumoglobulin, etoposide, and drugs for Mycobacterium tuberculosis including rifampin, ethambutol, isoniazid and pyramide. However, gastric lavage culture revealed MAC. Following treatment with clarithromycin, ciprofloxacin and amikacin, her condition gradually improved and she was discharged 3 months after admission. In SLE patients with pancytopenia and hyperferritinemia, MAC-associated HPS should be considered in the differential diagnosis.

Prognostic significance of vascular endothelial growth factor expression in human ovarian carcinoma

The influence of vascular endothelial growth factor (VEGF) expression and microvessel density (MVD) on prognosis and the relationship between VEGF expression and MVD in ovarian carcinoma are not well defined. We studied VEGF expression in parallel with MVD by immunohistochemistry in 94 ovarian tumours (64 malignant, 13 borderline, and 17 benign) and correlated the results with the clinicopathologic prognostic factors of the disease to clarify their significance in this disease. Assessment of VEGF mRNA isoforms by RT-PCR was also performed. Of the malignant, borderline, and benign ovarian tumours respectively, two (3%), four (31%) and 16 (94%) were negative, 31 (48%), seven (54%) and one (6%) had low expressions, and 31 (48%), two (15%) and none (0%) had high expressions of VEGF. There were significant associations between the VEGF expression and disease stage (P= 0.002), histologic grade (P= 0.0004), and patient outcome (P= 0.0002). MVD did not correlate significantly with the clinicopathologic parameters. Likewise, no correlation was found between MVD and VEGF expression. The survival of patients with high VEGF expression was significantly worse than that of patients with low and negative VEGF expression (P = 0.0004). Multivariate analysis revealed that disease stage and VEGF expression were significant and independent prognostic indicators of overall survival time (P = 0.008 and P = 0.006 respectively). These findings suggest that in conjunction with the established clinicopathologic prognostic parameters of ovarian carcinoma, VEGF expression may enhance the predictability of patients at high risk for tumour progression who are potential candidates for further aggressive therapy.

B7.1 expression by the weakly immunogenic F98 rat glioma does not enhance immunogenicity

Enhanced immunogenicity has been reported following transfection of a variety of immunogenic tumors with the B7.1 co-stimulatory molecule. The purpose of the present study was to determine if transfection of a weakly immunogenic rat brain tumor, the F98 glioma, with the gene encoding B7.1 could enhance its immunogenicity. F98 cells were transfected with a plasmid containing the B7.1 gene, and stable transfectants (F98/B7.1) were obtained. Flow cytometric analysis confirmed the expression of B7.1 and MHC class I antigens on the cell surface. To investigate the effects of B7.1 expression on the tumorigenicity of the F98 glioma, Fischer rats were implanted intracerebrally with either F98 (wild-type) or F98/B7.1 transfected cells. No significant differences in survival times were noted. Mean survival times of 21.8 and 24.0 days were observed for the respective groups at a challenge dose of 103 cells. These differences in survival time were not significant. To determine if expression of B7.1 enhanced the immunogenicity of the F98 glioma, rats were vaccinated weekly for 3 weeks with 107 mitomycin C-treated F98 or F98/B7.1 cells injected subcutaneously and then challenged intracerebrally with F98 cells 1 week later. Unvaccinated animals or those that received wild-type F98 cells as a vaccine had a survival time (mean +/- s.d.) of 22.3 +/- 1.5 days following tumor challenge versus 20.0 +/- 1.7 days for rats that had been vaccinated with F98/B7.1. Although we recognize that it might be possible to design more effective vaccination regimes, nevertheless, our data indicate that transfection of the B7.1 gene into the F98 rat glioma did not enhance its immunogenicity, and that other approaches will be required.

Neuropeptide Y-mediated pressor responses following high-frequency stimulation of the rat sympathetic nervous system

Neuropeptide Y (NPY) is a potent pressor agent that is stored in the sympathetic nerves. In several species, NPY release is augmented when sympathetic impulse frequencies increase. We investigated the extent to which NPY contributes to the pressor response to high- and low-frequency electrical stimulation. Rats were pithed, and the sympathetic trunk was stimulated at either 20 or 3 Hz in the presence or absence of antagonists of NPY and alpha and beta adrenergic receptors. The 20-Hz stimulation raised plasma NPY levels, but the 3-Hz stimulation did not. The 20-Hz stimulation caused marked pressor responses that were maintained for several minutes after the end of stimulation regardless of whether rats were pretreated with adrenergic blockers. The NPY antagonists BIBP 3226 and 1229U91 reduced the size of the pressor response that followed 20 Hz stimulation by >50%. The rapid blood pressure spikes that occur during electrical stimulation are attenuated by alpha adrenergic but not by NPY antagonists. There is a prolonged pressor response after high-frequency stimulation of the sympathetic trunk in pithed rats that begins after 1 to 2 min of stimulation and lasts approximately 10 min after the end of stimulation. At least half of this pressor response is mediated by NPY.

Dual role of protein kinase C in the regulation of cPLA2-mediated arachidonic acid release by P2U receptors in MDCK-D1 cells: involvement of MAP kinase-dependent and -independent pathways

Defining the mechanism for regulation of arachidonic acid (AA) release is important for understanding cellular production of AA metabolites, such as prostaglandins and leukotrienes. Here we have investigated the differential roles of protein kinase C (PKC) and mitogen-activated protein (MAP) kinase in the regulation of cytosolic phospholipase A2 (cPLA2)-mediated AA release by P2U-purinergic receptors in MDCK-D1 cells. Treatment of cells with the P2U receptor agonists ATP and UTP increased PLA2 activity in subsequently prepared cell lysates. PLA2 activity was inhibited by the cPLA2 inhibitor AACOCF3, as was AA release in intact cells. Increased PLA2 activity was recovered in anti-cPLA2 immunoprecipitates of lysates derived from nucleotide-treated cells, and was lost from the immunodepleted lysates. Thus, cPLA2 is responsible for AA release by P2U receptors in MDCK-D1 cells. P2U receptors also activated MAP kinase. This activation was PKC-dependent since phorbol 12-myristate 13-acetate (PMA) promoted down-regulation of PKC-eliminated MAP kinase activation by ATP or UTP. Treatment of cells with the MAP kinase cascade inhibitor PD098059, the PKC inhibitor GF109203X, or down-regulation of PKC by PMA treatment, all suppressed AA release promoted by ATP or UTP, suggesting that both MAP kinase and PKC are involved in the regulation of cPLA2 by P2U receptors. Differential effects of GF109203X on cPLA2-mediated AA release and MAP kinase activation, however, were observed: at low concentrations, GF109203X inhibited AA release promoted by ATP, UTP, or PMA without affecting MAP kinase activation. Since GF109203X is more selective for PKCalpha, PKCalpha may act independently of MAP kinase to regulate cPLA2 in MDCK-D1 cells. This conclusion is further supported by data showing that PMA-promoted AA release, but not MAP kinase activation, was suppressed in cells in which PKCalpha expression was decreased by antisense transfection. Based on these data, we propose a model whereby both MAP kinase and PKC are required for cPLA2-mediated AA release by P2U receptors in MDCK-D1 cells. PKC plays a dual role in this process through the utilization of different isoforms: PKCalpha regulates cPLA2-mediated AA release independently of MAP kinase, while other PKC isoforms act through MAP kinase activation. This model contrasts with our recently demonstrated mechanism (J. Clin. Invest. 99:1302-1310.) whereby alpha1-adrenergic receptors in the same cell type regulate cPLA2-mediated AA release only through sequential activation of PKC and MAP kinase.

Existence of a well-defined pulmonary lesion on plain chest film predicts poor response of chemotherapy in small cell lung cancer

BACKGROUND

Plain chest film is the most convenient and common tool used to evaluate the response of lung cancer to chemotherapy. Many authors tried to evaluate the use of plain chest films to predict chemotherapy response. This study investigated a new factor which could be used to predict the chemotherapy response of small cell lung cancer (SCLC).

METHODS

Sixty-two patients with cytopathologically proven small cell lung cancer receiving at least two courses of chemotherapy were included in this study. Among these patients, thirty-nine patients received six courses of chemotherapy. The regimens of chemotherapy are Etoposide (100 mg/m2) and Cisplatin (25 mg/m2). We divided these patients into two groups according to whether a well-defined pulmonary lesion excluding hilar and mediastinal lymphoadenopathy, could be identified on plain chest X-ray (CXR). Group I consisted of 31 patients with identified lesions on the CXR; group II consisted of 31 patients with unidentifiable lung lesions. CXRs were taken each time before chemotherapy and were collected and compared to evaluate the chemotherapy response. The 39 patients receiving six course of chemotherapy, were further divided into group I (n = 19) and group II (n = 20) to evaluate the chemotherapy response.

RESULTS

After two courses of chemotherapy, we found 23 patients [74.2% (23/31)] in group I had partial response(PR) as compared to 12 patients [38.7% (12/31)] in group II (P < 0.05). For the 39 patients receiving six courses of chemotherapy, we could find only five patients [16.1% (5/19)] in group I who had a complete response (CR) as compared to 17 patients [85% (17/20)] in group II (P < 0.001).

CONCLUSION

For patients with SCLC, a well-defined lung lesion on a CXR could be an important new factor to predict the chemotherapy response. It could predict less responsiveness to chemotherapy.

Major species variation in the expression of galanin messenger ribonucleic acid in mammalian celiac ganglion

To determine whether galanin may be a sympathetic neurotransmitter in the pancreas of primates and rats as well as dogs, the expression of the galanin gene was examined in the celiac ganglion of these species by in situ hybridization and RIA. Intense hybridization signal for galanin messenger RNA (mRNA) was observed in every neuronal cell body of the dog celiac ganglion. However, significant hybridization signal for galanin mRNA was seen in only 24 +/- 5% of celiac ganglion cell bodies in monkeys and was absent in rats. RIA of celiac ganglion extracts confirmed this species variation; galanin-like immunoreactivity was highest in dog celiac ganglion (158 +/- 13 pmol/g), present in monkeys (34 +/- 7 pmol/g), and undetectable in rats (< 0.8 pmol/g). In contrast, the celiac ganglia of all three species showed intense hybridization signal for neuropeptide-Y (NPY) mRNA in the majority of neuronal cell bodies (dog, 82 +/- 4%; monkey, 92 +/- 2%; rat, 91 +/- 3%), and the celiac ganglion NPY immunoreactivity content was high in all three species (dog, 1064 +/- 155 pmol/g; monkey, 3180 +/- 745 pmol/g; rat, 3412 +/- 347 pmol/g). Thus, there is a marked species variation in the expression of the galanin, but not the NPY, gene in the celiac ganglion of dogs, monkeys, and rats. These data suggest that galanin is an important sympathetic neurotransmitter in the pancreatic islets of dogs, but not those of primates or rats.

In the rat, endogenous nitric oxide modulates the response of the hypothalamic-pituitary-adrenal axis to interleukin-1 beta, vasopressin, and oxytocin

Nitric oxide (NO) synthase (NOS), the enzyme responsible for NO formation, is found in hypothalamic neurons containing oxytocin (OT), vasopressin (VP), and to a lesser extent corticotropin-releasing factor (CRF). Because NO is reported to modulate endocrine activity, we have investigated the hypothesis that endogenous NO participates in ACTH released by various secretagogues in the rat. In the adult male rat, the intravenous injection of interleukin-1 beta (IL-1 beta; 0.2-0.3 micrograms/kg), VP (0.3-0.9 micrograms/kg), and OT (30 micrograms/kg) significantly increased plasma ACTH and corticosterone levels. Pretreatment with the L-form, but not the D-form, of N omega nitro-L-arginine-methylester (L-NAME; a specific inhibitor of NOS) markedly augmented the effects of these secretagogues whether it was injected acutely or over a 4 d period. Blockade of NOS activity also caused significant (P < 0.01) extensions of the duration of action of IL-1 beta, VP, and OT. In contrast, L-NAME did not significantly alter the stimulatory action of peripherally injected CRF, or centrally administered IL-1 beta. Administration of L-arginine, but not D-arginine (100 mg/kg), used as a substrate for basal NO synthesis and which did not by itself alter the activity of the hypothalamic-pituitary-adrenal (HPA) axis, blunted IL-1-induced ACTH secretion, and reversed the interaction between L-NAME and IL-1 beta. The stimulatory action of endotoxin, a lipopolysaccharide that releases endogenous cytokines, was also augmented by inhibition of NO formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Modulation of vascular function by neuropeptide Y during development of hypertension in spontaneously hypertensive rats

Neuropeptide Y (NPY) is a sympathetic cotransmitter and a platelet-derived factor which causes vasoconstriction, potentiation of norepinephrine (NE) action, and vascular mitogenic effects. Reciprocally, NE markedly enhances the actions of NPY. We studied vasopressor effects of NPY and sources of peptide release during the development of hypertension in spontaneously hypertensive rats (SHR). Conscious SHR (4 and 16 weeks old) had higher resting plasma levels of NE and epinephrine than age-matched Wistar-Kyoto (WKY) rats, but similar NPY immunoreactivity (NPY-ir) levels in platelet-poor plasmas (PPP). In both strains, NPY-ir levels in PPP were higher in 4-week-old than in older rats. However, at all ages (4-24 weeks) SHR had markedly elevated NPY-ir content in platelet-rich-plasmas than WKY rats, although levels declined with age and hypertension. In the superior mesenteric artery, NPY-ir content (per mg) was significantly higher in 4-week-old but lower in 16-week-old SHR than in WKY rats, suggesting greater sympatho-neural NPY stores and release (leading to depletion) during the development of hypertension. Four-week-old SHR also tended to have higher NPY-ir content in the adrenal medullae and coeliac ganglia but a lower content in the kidney than WKY rats; these differences disappeared with age. Pressor responsiveness to alpha-agonists and NPY were similar in both strains at 4 weeks. While unchanged by age in WKY rats, adrenergic and NPY-mediated vasopressor responses became augmented in 16- to 24-week-old SHR (compared with WKY rats); this hyperresponsiveness was not completely abolished by ganglionic blockade and not observed with vasopressin.(ABSTRACT TRUNCATED AT 250 WORDS)

Antiserum against neuropeptide Y enhances the nicotine-mediated release of catecholamines from cultured rat adrenal chromaffin cells

A primary culture of chromaffin cells was prepared from adult rats and the stability of cell contents, NPY and catecholamines (CAs), during the culture was studied. The responsiveness of cultured chromaffin cells to NGF or secretagogues and the possible role of NPY on the CA secretion from cultured chromaffin cells were investigated. After plating of isolated cells, there was marked decrease in the cell content of CAs but a significant increase in the cell content of NPY. Though both NPY and CAs in the cultured cells were positively regulated by NGF, the results of this study seemed to suggest a differential regulation for NPY and CAs in the chromaffin cell. The cultured chromaffin cells secreted NPY and CAs in response to stimulation by nicotine. The nicotine stimulated secretion of CA was enhanced by the presence of IgG fraction, prepared from NPY antiserum, in the secretion medium. The results suggested that NPY was co-released with CAs from chromaffin cells and then acted as a modulator on CA secretion.

Mitogenic effect of neuropeptide Y in rat vascular smooth muscle cells

Neuropeptide Y (NPY) is a vasoconstrictor released with norepinephrine from perivascular sympathetic nerves. Since sympathetic nerves appear to play a role in vascular smooth muscle cell (SMC) hypertrophy, we studied the effects of NPY on proliferation of cultured rat aorta- and vena cava-derived SMC. Both cell types displayed high-affinity NPY binding sites with displacement characteristics of [Pro34]NPY > NPY(13-36) > NPY(18-36) in aorta and [Pro34]NPY = NPY(13-36) = NPY(18-36) in the vena cava. Incubation with NPY (50-1000 nM) for 48 h increased by up to twofold cell number and [3H]-thymidine incorporation in both cell types (aortic more sensitive to NPY than venous). Following incubation with NPY, the disappearance of NPY immunoreactivity (-IR) from media was markedly delayed in the presence of SMC, and cell content of NPY-IR increased in a dose-dependent manner, indicating that SMC either diminish degradation of the peptide (possibly by internalization) or secrete endogenous NPY (or both). Structure-activity relationship studies with NPY(18-36) indicated involvement of Y1 receptors in mitogenesis. Thus, NPY has a mitogenic effect (probably mediated by Y1 receptors) and, therefore, may be a sympathetic trophic factor involved in vascular hypertrophy.

A confined variable region confers ligand specificity on fibroblast growth factor receptors: implications for the origin of the immunoglobulin fold

Binding of cellular growth factors to their receptors constitutes a highly specific interaction and the basis for cell and tissue-type specific growth and differentiation. A unique feature of fibroblast growth factor (FGF) receptors is the multitude of structural variants and an unprecedented degree of cross-reactivity between receptors and their various ligands. To examine receptor-ligand specificity within these families of growth factors and receptors, we used genetic engineering to substitute discrete regions between Bek/FGFR2 and the closely related keratinocyte growth factor receptor (KGFR). We demonstrate that a confined, 50 amino acid, variable region within the third immunoglobulin-like domain of Bek and KGFR exclusively determines their ligand binding specificities. Replacing the variable region of Bek/FGFR2 with the corresponding sequence of KGFR resulted in a chimeric receptor which bound KGF and had lost the capacity to bind basic FGF. We present evidence that the two variable sequences are encoded by two distinct exons that map close together in the mouse genome and follow a constant exon, suggesting that the two receptors were derived from a common gene by mutually exclusive alternative mRNA splicing. These results identify the C-terminal half of the third immunoglobulin-like domain of FGF receptors as a major determinant for ligand binding and present a novel genetic mechanism for altering receptor-ligand specificity and generating receptor diversity.

C-terminal neuropeptide Y fragments are mast cell-dependent vasodepressor agents

Neuropeptide Y (NPY) is a well-established vasopressor agent present in sympathetic perivascular nerves. Recently, it was found that high doses of the peptide cause a biphasic pressor-depressor response upon intravenous administration. We now report that C-terminal NPY fragments (NPY-(18-36) and NPY-(22-36] given intravenously to conscious or pithed (areflexive) male Sprague-Dawley rats mimic the depressor component of the NPY-(1-36) response while displaying very low pressor activity. Additionally, we have found that the depressor component is blocked by the histamine H1-antagonist, mepyramine. Since the fragment, NPY-(22-36), was equipotent with NPY in inducing histamine release from isolated peritoneal mast cells, we conclude that short C-terminal NPY fragments, like NPY itself, act on mast cells to initiate histamine-mediated cardiovascular actions. Such actions may conceivably be accounted for by the abundance of positively charged amino acid residues in the C-terminus. Moreover, these fragments have little affinity for vascular NPY receptors, as indicated by their poor ability to displace iodinated NPY or peptide YY (PYY) from specific binding sites on vascular smooth muscle cells derived from rat aorta. In conclusion, we propose that short C-terminal NPY fragments, which contain several positively charged amino acid residues, retain the ability of NPY to release histamine from rat mast cells while being essentially devoid of direct vascular motor activity.

Cardiovascular, neuropeptide Y, and adrenergic responses in stress are sexually differentiated

Cardiovascular and sympatho-adrenomedullary responsiveness at rest and during stress were studied in weight-matched, sexually mature male and female rats. At rest, although there were no sex differences in cardiovascular parameters, females had two-fold higher plasma levels of norepinephrine (NE) and epinephrine. Resting plasma levels of neuropeptide Y-immunoreactivity (NPY-ir, a putative sympathetic cotransmitter and a vasoconstrictor) were similar in both sexes. Stresses of handling and cold (4 degrees C) water exposure induced greater pressor and tachycardic responses in males than in females. Males but not females exhibited a protracted recovery from the stress-induced pressor responses and a 2-fold increase in plasma NPY-ir suggesting that NPY release is sexually differentiated. Only in males, low basal plasma NE and NPY-ir levels inversely correlated with greater cold-induced pressor responses. Furthermore, in areflexic pithed rats, pressor adrenergic and NPY responses were greater in males than in females suggesting the possibility of "down"-regulation of vascular adrenergic receptors in females (due to elevated circulating catecholamines) and "up"-regulation of NPY and adrenergic receptors in males.

Neuropeptide Y receptor subtypes, Y1 and Y2

Heterogeneity among NPY (and PYY) receptors was first proposed on the basis of studies on sympathetic neuroeffector junctions, where NPY (and PYY) can exert three types of action: 1) a direct (e.g., vasoconstrictor) response; 2) a postjunctional potentiating effect on NE-evoked vasoconstriction; and 3) a prejunctional suppression of stimulated NE release; the two latter phenomena are probably reciprocal, since NE affect NPY mechanisms similarly. It was found that amidated C-terminal NPY (or PYY) fragments, e.g., NPY 13-36, could stimulate selectively prejunctional NPY/PYY receptors, which were termed Y2-receptors. Consequently, the postjunctional receptors which were activated poorly by NPY/PYY fragments, were termed Y1-receptors. Later work has indicated that the Y2-receptor may occur postjunctionally in selected sympathetic effector systems. The central nervous system appears to contain a mixture of Y1- and Y2-receptors as indicated by functional as well as binding studies. For instance, NPY and NPY 13-36 produced diametrically opposite effects on behavioral activity, indicating the action of the parent peptide on two distinct receptors. Cell lines, most importantly neuroblastomas, with exclusive populations of Y1- or Y2-receptors, have been characterized by binding and second messenger studies. In this work, selective agonists for the two receptor subtypes were used. Work of many investigators has formed the basis for subclassifying NPY/PYY effects being mediated by either Y1- or Y2-receptors. A preliminary subclassification based on effects of NPY, PYY, fragments and/or analogs is provided in Table 6. It is, however, to be expected that further receptor heterogeneity will be revealed in the future. It is argued that mast cells possess atypical NPY/PYY receptors. The histamine release associated with stimulation of the latter receptors may, at least in part, underlie the capacity of NPY as well as of short C-terminal fragments to reduce blood pressure. Fragments, such as NPY 22-36, appear to be relatively selective vasodepressor agents because of their weak vasopressor properties.(ABSTRACT TRUNCATED AT 400 WORDS)

Membrane attack complex of complement in Henoch-Schönlein purpura skin and nephritis

The present study using direct immunofluorescence with monoclonal antibodies to C5b-9 complex-related antigens was undertaken to determine whether complement activation in Henoch-Schönlein purpura (HSP) causes assembly of the membrane attack complex of complement (MAC) in skin and nephritis lesions. The deposition of C5, C6, C7, C8, C9, and C5b-9 neoantigens was noted in the vascular walls of papillary dermis and/or subpapillary dermal plexus of the vessels in 11 out of 15 patients with HSP. Their presence in vessel walls indicates complement activation which leads to terminal complement activation. There were small deposits of S protein at the same sites in three of the 11 skin specimens. Thus, the majority of C5b-9 demonstrated in HSP skin was the cytolytically active C5b-9 complex, MAC. Granular deposits of C5b-9 related antigens without S protein were also found in the capillary walls and mesangium of the glomeruli of two out of four specimens from patients with HSP nephritis; in the other two S protein was colocalized with the deposition of C5b-9. The results of the present study indicate that complement activation leading to generation of MAC may possibly be involved in the pathogenesis of vascular injury in a significantly large number of skin lesions and of HSP nephritis.

Biphasic blood pressure response to neuropeptide Y in anesthetized rats

The effects of neuropeptide Y (NPY) on systemic arterial blood pressure and heart rate were studied in anesthetized intact and pithed rats. I.v. doses of NPY (0.3-30 nmol/kg) raised the mean arterial blood pressure dose dependently. At doses of greater than or equal to 3.0 nmol/kg, the initial pressor response was followed by a dose-dependent fall in blood pressure in intact and pithed rats. The depressor response was accompanied 1-2 min after the NPY injection by a slight increase in heart rate in pithed rats but not in intact rats, and 10 min after the injection by a decrease in heart rate in intact rats. After repeated injections of NPY, the depressor effect vanished, whereas the integrated pressor response over time was markedly enhanced. After pretreatment with the histamine H1-receptor antagonist, mepyramine, or with the histamine liberator, compound 48/80, the pressor response to NPY remained but the depressor response disappeared. We suggest that the marked fall in blood pressure can be attributed to NPY-evoked histamine release from mast cells.