Expression of the bile salt export pump is maintained after chronic cholestasis in the rat

BACKGROUND & AIMS

This study assessed the expression of the recently identified adenosine triphosphate-dependent bile salt export pump and the functional ability to excrete bile salts in cholestatic models in the rat.

METHODS

The effects of common bile duct ligation, endotoxin, and ethinylestradiol on bile salt export pump messenger RNA levels, protein expression, and tissue localization were determined. Changes in the expression of 3 other hepatocyte membrane transporters (Na(+) taurocholate cotransporter, multispecific organic anion transporter, and P-glycoprotein) were also determined for comparison. Functional assessment of bile salt excretion was determined after bile duct ligation.

RESULTS

Expression of the bile salt export pump was diminished but relatively preserved compared with other membrane transporters. Tissue localization of the bile salt export pump persisted at the canalicular domain in all 3 models. In contrast, expressions of the Na(+) taurocholate cotransporter and multispecific organic anion transporter were more profoundly diminished. P-glycoprotein levels increased severalfold with common bile duct ligation but were unchanged with either endotoxin or ethinylestradiol. The capacity to excrete bile salts was relatively maintained 3 and even 14 days after bile duct ligation.

CONCLUSIONS

Alterations in expression of the bile salt export pump may account for the functional alterations of bile salt secretion observed in cholestasis. However, relative preservation of expression is associated with persistent bile salt excretion and may lessen the extent of liver injury produced by bile salt retention.

Elevated transglutaminase-induced bonds in PHF tau in Alzheimer's disease

Transglutaminase-induced epsilon-(gamma-glutamyl)lysine bonds covalently cross-link and polymerize peptides into insoluble high molecular weight protein aggregates resistant to degradation and proteolytic digestion. We investigated the hypothesis that excessive deposition of epsilon-(gamma-glutamyl)lysine bonds is a neuropathological mechanism which induces the polymerization of tau protein into stable aggregates leading to the formation of paired helical filaments (PHFs) which deposit into neurofibrillary tangles in Alzheimer's disease (AD) brain. We demonstrate a significant (45%) elevation in epsilon-(gamma-glutamyl)lysine cross-links in AD cortex as compared to control cortex. In vivo, PHF tau, and high and medium molecular weight neurofilament proteins have significantly greater cross-linking by epsilon-(gamma-glutamyl)lysine bonds in AD brains as compared to controls. The cross-linking of PHF tau occurs both intra-molecularly and inter-molecularly. The inter-molecular cross-linking of tau could account for the formation of high molecular weight tau polymers. These results suggest that transglutaminase-induced cross-linking of tau protein could play a role in the formation and stabilization of neurofibrillary tangles. Inhibition of transglutaminase-induced cross-linking may therefore, provide a novel strategy for the treatment of AD.

Modification of EWS/WT1 functional properties by phosphorylation

In many human cancers, tumor-specific chromosomal rearrangements are known to create chimeric products with the ability to transform cells. The EWS/WT1 protein is such a fusion product, resulting from a t(11;22) chromosomal translocation in desmoplastic small round cell tumors, where 265 aa from the EWS amino terminus are fused to the DNA binding domain of the WT1 tumor suppressor gene. Herein, we find that EWS/WT1 is phosphorylated in vivo on serine and tyrosine residues and that this affects DNA binding and homodimerization. We also show that EWS/WT1 can interact with, and is a substrate for, modification on tyrosine residues by c-Abl. Tyrosine phosphorylation of EWS/WT1 by c-Abl negatively regulates its DNA binding properties. These results indicate that the biological activity of EWS/WT1 is closely linked to its phosphorylation status.

Antisense oligodeoxynucleotide of glyceraldehyde-3-phosphate dehydrogenase gene inhibits cell proliferation and induces apoptosis in human cervical carcinoma cell lines

Tumor cells characteristically exhibit an increased rate of glycolysis. A higher level of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA was found in human uterine cervical cancers. This study was designed using GAPDH antisense oligodeoxynucleotide (ODN) phosphorothioate (PS) to evaluate how alterations of GAPDH expression in human cervical carcinoma could influence growth inhibition and induction of apoptosis. Northern blot analyses revealed that the levels of GAPDH gene expression were strongly elevated in three cervical carcinoma cell lines (HeLa, CUMC-3, and CUMC-6) compared with normal cervical tissue. Reverse transcription-polymerase chain reaction (RT-PCR) showed that expression of the GAPDH gene was inhibited by 10 microM of GAPDH antisense ODN in all three cell lines. Western blot analysis showed that the levels of GAPDH protein were decreased or absent after GAPDH antisense ODN treatment for 12 days in cultured cervical carcinoma cell lines. Cervical carcinoma cell lines exposed to GAPDH antisense ODN showed reduced cellular proliferation, which was accompanied by reduced colony-forming efficiency. This effect of GAPDH antisense ODN on cultured carcinoma cells was associated with the apoptotic process, including increased DNA fragmentation. These results suggest that future gene therapy using antisense ODN directed against cervical cancer-specific GAPDH mRNA might be another therapeutic tool against human uterine cervical carcinomas.

4-Aminopyridine antagonizes the acute relaxant action of metformin on adrenergic contraction in the ventral tail artery of the rat

The ability of metformin (MF) to acutely relax phenylephrine (PE)-induced contraction in the isolated rat tail artery is reported to be accompanied by repolarization of the arterial smooth muscle cell (SMC) membranes. These membranes contain potassium (K) channels which if opened could mediate such repolarization and resultant relaxation. We have shown that the acute relaxation of rat tail arterial tissue rings by graded levels of MF > or = 0.24 mmol/L is markedly antagonized by a high concentration of tetraethylammonium (TEA; 10 mmol/L) which nonselectively inhibits nearly all K channels. Thus, we tested effects of more selective inhibitors of K channels in the same tissue. We also tested MF for relaxation of contractions induced by high levels of extracellular K. To avoid confounding variables, we also conducted these tests in arterial rings in which endothelium and sympathetic nerve endings had been removed. In the absence of K channel inhibition, half-maximal PE-induced contractions were rapidly relaxed by all levels of MF with an EC50 of 1.7+/-0.2 mmol/L (n=8 rings). 1 mmol/L 4-aminopyridine (4AP) which only inhibits voltage-operated and ATP-sensitive K channels markedly antagonized this relaxation, shifting the EC50 for MF to 7.5+/-0.7 mmol/L (n=8; p < 0.05). TEA at 1 mmol/L (which only inhibits calcium-activated K channels), barium at 20 micromol/L (which only inhibits inward rectifier K channels) and glyburide at 5 micromol/L (which only inhibits ATP-sensitive K channels) did not alter this relaxation. Finally, MF failed to relax contractions produced by elevations of extracellular K to levels high enough to abolish the K gradient across arterial SMC membranes. Thus, acute relaxation of rat tail arterial smooth muscle by MF may be dependent on the transmembrane K gradient and mediated at least in part by specific activation of K efflux through 4AP-sensitive voltage-dependent K channels in arterial SMC membranes.

Inhibitory effects of chlorophyllin on 7,12-dimethylbenz[a]anthracene-induced bacterial mutagenesis and mouse skin carcinogenesis

Chlorophyllin (CHL), a water-soluble derivative of chlorophyll, has been used for the treatment of several abnormal human conditions without apparent toxicity. Recent studies have revealed that CHL has the excellent chemopreventive potential. In the present investigation, we have found the inhibitory activities of CHL against 7,12-dimethylbenz[a]anthracene (DMBA)-induced mutagenesis in Salmonella typhimurium TA100 and also on DMBA-initiated and 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-promoted mouse skin tumor formation. The incidence and the multiplicity of skin tumors were not significantly decreased in mice by a single topical application of CHL prior to the DMBA treatment, but there was a marked suppression of papillomagenesis in mice treated with CHL during the promotional stage. Furthermore, the formation of DMBA-induced papillomagenesis was reduced in all mice that had received CHL for 6 weeks following treatment with TPA for 6, 18 and 24 weeks. These results indicate that CHL can inhibit both tumor promotion and the progression of papillomagenesis in the two-stage mouse skin carcinogenesis induced by DMBA and TPA.

Cervical thymic cyst in the elderly: a case report

Cervical thymic cyst is uncommon and usually occurs in the first and second decades. Cervical thymic cyst after the third decade is so rare that it is very difficult to diagnose in spite of its typical location. We present a rare case of cervical thymic cyst in the lower left - anterior of the neck in a 50-year-old woman. It showed well-defined, anechoic cyst on ultrasonography and non-enhancing low attenuation mass on CT. A typical anatomic relationship was noted between the mass and carotid sheath.

Embolization of superior mesenteric artery branches in dogs. Ischemic bowel changes depend on location of vessel occlusion and embolic materials

OBJECTIVE

To evaluate the degree of ischemic changes of the small intestine after arterial embolization of proximal or distal arteries with Gelfoam particles and coils in dogs.

METHODS

Superselective arterial embolization in 18 dogs was performed using a coaxial catheter system. Gelfoam occlusion of the proximal level of ileal or jejunal arteries was performed in four dogs (group A). Gelfoam occlusion of the distal level was performed in four dogs (group B). Coil occlusion of the proximal level was performed in five dogs (group C). Coil occlusion of the distal level was performed in five dogs (group D). All 18 dogs were killed 1 day after the procedure. Gross and microscopic findings were evaluated.

RESULTS

The embolizations were successful in all dogs. In group B, significant mucosal destruction, lymphocyte proliferation of the submucosa and mucosa, and diffuse swelling in all layers of the intestine were found in all four dogs. Three revealed diffuse ischemic changes and one showed focal ischemic changes. In groups A and C, all the layers of the intestine were intact and did not show any ischemic changes. In group D, one dog showed erosion of a small portion of mucosa and lymphocytic infiltration. The other dogs showed nonspecific findings in all layers of the intestine.

CONCLUSIONS

Proximal embolization with Gelfoam and coils as well as distal embolization with coils did not cause ischemia. However, ischemic changes in the intestinal wall could be observed after distal embolization with Gelfoam.

Determinants of mechanical properties in the developing ovine thoracic aorta

We previously reported changes in mechanical properties and collagen cross-linking of the ovine thoracic aorta during perinatal development and postnatal maturation, and we now report changes in biochemical composition (elastin, collagen, and DNA contents per mg wet wt) over the same developmental intervals. A comparison of results from the present and previous studies has yielded novel and important observations concerning the relationship between aortic mechanics and composition during maturation. Developmental changes in aortic incremental elastic modulus at low tensile stress (E(low)) closely followed changes in relative elastin content (i.e., per mg wet wt). An 89% increase in E(low) during the perinatal period was associated with a 69% increase in relative elastin content, whereas neither variable changed during postnatal life. Incremental elastic modulus at high tensile stress (E(high)) did not change during the perinatal period but increased 88% during postnatal life. This pattern closely paralleled changes in collagen cross-linking index, which did not change perinatally but almost doubled postnatally. In contrast, relative collagen content (per mg wet wt) increased only slightly from fetal to adult life, a trend that was unrelated to aortic mechanics. Substantial, progressive decreases in measures of wall viscosity (pressure wave attenuation coefficient and viscoelastic phase angle) from fetal to adult life followed the pattern observed for relative DNA (smooth muscle cell) content (per mg wet wt). Our findings suggest that accumulation of elastin per milligram wet weight contributes most to developmental changes in E(low), change in collagen cross-linking is the primary determinant of developmental changes in E(high), and cell accumulation contributes most to developmental changes in wall viscosity.

Effectiveness of preoperative transarterial chemoembolization in presumed inoperable hepatoblastoma

PURPOSE

To evaluate the effectiveness and therapeutic role of preoperative transarterial chemoembolization (TACE) of hepatoblastoma.

MATERIALS AND METHODS

Four patients (one boy, three girls) with unresectable hepatoblastoma were treated twice with preoperative TACE in an effort to improve the surgical and clinical outcome. The patients ranged in age from 8 to 27 months (mean, 15 months). The first TACE was performed superselectively in tumor feeding arteries. The second TACE was performed 3 weeks later. Surgical hepatic resection was performed 1 month after the second TACE. Contrast-enhanced computed tomography (CT) was used to evaluate changes in size, volume, internal texture, and margin of the masses. The toxicity of the chemotherapeutic drugs was evaluated by blood chemistry analysis (AST/ALT, alpha-FP) performed before and after TACE, and after surgery.

RESULTS

TACE allowed subsequent surgical resection in all four patients, who remained disease free 16-52 months after operation. There were no major problems related to TACE. There was no chemotherapeutic agent toxicity from TACE. The average largest diameters and volumes of the tumors decreased by 31% (8.3 to 5.6 cm) and 69% (317 to 93 cm2), respectively.

CONCLUSION

TACE provided subsequent successful surgical resection and good long-term results in all four patients. The hepatoblastomas were initially considered inoperable because of extensive hepatic involvement and indistinct margins.

RBP1 recruits both histone deacetylase-dependent and -independent repression activities to retinoblastoma family proteins

Retinoblastoma (RB) tumor suppressor family proteins block cell proliferation in part by repressing certain E2F-specific promoters. Both histone deacetylase (HDAC)-dependent and -independent repression activities are associated with the RB "pocket." The mechanism by which these two repression functions occupy the pocket is unknown. A known RB-binding protein, RBP1, was previously found by our group to be an active corepressor which, if overexpressed, represses E2F-mediated transcription via its association with the pocket. We show here that RBP1 contains two repression domains, one of which binds all three known HDACs and represses them in an HDAC-dependent manner while the other domain functions independently of the HDACs. Thus, RB family members repress transcription by recruiting RBP1 to the pocket. RBP1, in turn, serves as a bridging molecule to recruit HDACs and, in addition, provides a second HDAC-independent repression function.

Overexpression of four-repeat tau mRNA isoforms in progressive supranuclear palsy but not in Alzheimer's disease

Perturbations in the microtubule-associated protein tau occur in several human neurodegenerative diseases. In Alzheimer's disease and progressive supranuclear palsy (PSP), tau proteins assemble into straight and paired helical filaments that form intraneuronal deposits of neurofibrillary tangles (NFTs). The mechanisms underlying the aberrant assembly of tau into NFTs is unknown. To determine whether alterations in the expression of the carboxyl-terminal variants of tau contribute to NFT formation, we analyzed tau mRNA isoform expression in select regions of control, Alzheimer's disease, and PSP brains. In Alzheimer's disease, there were no alterations in tau mRNA isoform expression. However, in PSP, the levels of tau mRNA isoforms containing four microtubule binding domains were increased in the brainstem but not the frontal cortex or cerebellum. The brainstem in PSP has extensive NFT pathology, whereas the frontal cortex and cerebellum are relatively spared, suggesting that alterations in tau mRNA isoform expression occur in NFT-vulnerable regions in this disease. An increase in the four-repeat tau mRNA may lead to an increase in four-repeat tau protein isoforms and may contribute to the formation of NFTs in PSP. A similar increase in four-repeat tau mRNA has been reported for mutations associated with frontotemporal dementia and parkinsonism linked to chromosome 17.

Renal artery embolization controls intractable pain in a patient with polycystic kidney disease

A 65-year-old man with adult polycystic kidney disease (APKD) and chronic renal failure suffered from intractable abdominal pain and distension for 2 weeks. Meperidine infusion did not alleviate his pain. However, pain and abdominal distension were successfully controlled by embolization of both renal arteries.

The Epstein-Barr virus latency BamHI-Q promoter is positively regulated by STATs and Zta interference with JAK/STAT activation leads to loss of BamHI-Q promoter activity

In Epstein-Barr virus (EBV)-associated tumors in nonimmunocompromised patients, EBV gene expression is highly restricted. EBV-encoded nuclear antigen (EBNA)-1 is expressed, whereas the immunogenic and proliferative EBNAs are not. This pattern of EBNA expression is generated by usage of the BamHI-Q promoter (Qp). We have determined that the JAK/STAT pathway positively regulates Qp activity. In transient-transfection assays, a Qp-CAT reporter was activated by cotransfected JAK-1 and by treatment of cells with the cytokine IL-6. The ability of Qp to bind signal transducer and activator of transcription (STAT) proteins was directly demonstrated by electrophoretic mobility-shift assay, and mutation of potential STAT-binding sites reduced Qp responsiveness to Janus kinase (JAK)-1. Consistent with a role for STATs in Qp function, Qp using Burkitt's lymphoma Rael cells and cultured nasopharyngeal carcinoma (NPC) cells contained nuclear STAT protein. We investigated whether the inability to maintain EBV-positive NPC cell lines in culture was related to Qp activity. Passaging of the NPC cell line HK666 led to activation of expression of BZLF1, which encodes Zta and loss of Qp function. Transient expression assays linked Zta expression to the down-regulation of Qp. Cotransfection of Zta reduced Qp activity in reporter assays. This negative regulation required Zta DNA-binding activity. We provide evidence that Zta up-regulation of p53 leads to p53-mediated interference with JAK/STAT activation of Qp. The data imply that JAK/STAT signaling has a role in EBV-associated malignancies.

Reduced high-affinity agonist binding at the M(1) muscarinic receptor in Alzheimer's disease brain: differential sensitivity to agonists and divalent cations

M(1) muscarinic acetylcholine receptor (M(1)AchR)-G protein coupling, as measured by high-affinity agonist binding, was examined in membranes prepared from postmortem human temporal cortex (Brodmann area 38) from individuals with Alzheimer's disease (AD, n = 8) and age-matched controls (n = 6). Binding competitions between the M(1)AchR-selective antagonist [(3)H]pirenzepine ([(3)H]PZ) and muscarinic agonists carbachol, acetylcholine, oxotremorine, and oxotremorine M were conducted. In the presence of 1 mM MgCl(2), the inhibition of [(3)H]PZ binding by carbachol, acetylcholine, or oxotremorine M was best described by a two-affinity state model for control and AD cases, while oxotremorine binding affinity was best fit to a single-state model. Although both control and AD groups had similar K(D) values for the high- and low-affinity agonist binding sites, the proportion of M(1)AchRs exhibiting high affinity for carbachol and acetylcholine was reduced by 48 and 33%, respectively, in AD membranes relative to controls (P < 0.05). No changes in the binding of the oxotremorine M or oxotremorine were noted. The nonhydrolyzable guanine nucleotide GppNHp (100 microM) reduced the proportion of M(1)AchRs with high affinity for agonists in both control and AD membranes. Substitution of 1 mM MnCl(2) for MgCl(2) restored high-affinity carbachol binding at the M(1)AchR in AD membranes similar to that seen in controls. In the presence of 1 mM MnCl(2), agonist binding in controls did not differ from 1 mM MgCl(2). In the absence of cations (1 mM EDTA), no differences between control and AD M(1)AchR carbachol binding were observed. Thus, the loss of high-affinity agonist binding at the M(1)AchR in AD is dependent on the agonist and cation studied.

Significance of P53 and Rb protein expression in surgically treated non-small cell lung cancers

BACKGROUND

Alterations of the P53 or Rb gene are among the most frequently observed genetic changes in primary lung cancer. Nevertheless, there has been no final conclusion on the relationship between P53 or Rb protein expression and clinico-pathological parameters in primary lung cancer. A large-scale study was performed to examine the clinicopathological and prognostic significance of P53 and Rb expressions in 207 surgically resected non-small cell lung cancer (NSCLC) patients.

METHODS

Tumor specimens were obtained from 207 primary NSCLC surgically resected from January 1990 through December 1994. The avidin-biotin-peroxidase method was used to determine the expression of P53 or Rb of tumor cells using anti-P53 or anti-Rb monoclonal antibodies. The relationships between P53 or Rb protein expression and the clinicopathological parameters were analyzed.

RESULTS

Expression of P53 or Rb protein was detected in 115 (55.6%) and 136 (65.7%) of the 207 lung tumors, respectively. P53 had significantly higher positive results in patients with regional lymph node metastasis and advanced tumor stage. Rb expression was significantly lower in lung cancers with a macro- or microscopic picture of tumor necrosis. Additionally, an inverse correlation between the expression of Rb and P53 was found. By multiple variate analysis, P53 expression and pathological stage were independent, significant prognostic factors. Further analysis demonstrated P53 expression was an independent prognostic factor in stage 1, but not in other stages.

CONCLUSIONS

P53 expression is especially useful as a prognostic factor in stage 1 lung cancer.

Inhibition of protein kinase A phase delays the mammalian circadian clock

The suprachiasmatic nuclei (SCN) contain the mammalian circadian clock whose rhythm of firing rate can be recorded in vitro for several days. Application of a protein kinase A (PKA) inhibitor onto the SCN at Zeitgeber time (ZT) 10 on the first day in vitro phase delayed the rhythm of firing rate expressed by SCN neurons on the subsequent day in vitro. Application of the inhibitor (Rp-cAMPS) at other circadian phases did not phase shift the rhythm. These results suggest that during approximately 1 h in the late subjective day the presence and activity of PKA plays a role in setting the phase of the mammalian circadian clock.

Anti-tumor promoting potential of naturally occurring diarylheptanoids structurally related to curcumin

In recent years, there have been considerable efforts to search for naturally occurring substances for intervention of carcinogenesis. Many components from medicinal or dietary plants have been identified to possess potential chemopreventive properties. For instance, curcumin, a yellow colouring agent from turmeric (Curcuma longa Linn., Zingiberaceae) has been shown to inhibit tumor formation in diverse animal models. Alpinia oxyphylla Miquel that also belongs to ginger family has been used in oriental herbal medicine. In the present work, we have evaluated the anti-tumor promoting potential of yakuchinone A (1-[4'-hydroxy-3'-methoxyphenyl]-7-phenyl-3-heptanone) and yakuchinone B (1-[4'-hydroxy-3'-methoxyphenyl]-7-phenylhept-1-en-3-one), major pungent ingredients of A. oxyphylla. Thus, topical application of yakuchinone A or B significantly suppressed TPA-induced epidermal ornithine decarboxylase activity. They also reduced TPA-stimulated production of tumor necrosis factor-alpha in cultured human promyelocytic leukemia (HL-60) cells. Both compounds blunted the TPA-induced superoxide generation in differentiated HL-60 cells in a concentration-related manner and also inhibited lipid peroxidation in rat brain homogenates. Furthermore, yakuchinone A and yakuchinone B nullified the activation of the activator protein-1 (AP-1) in immortalized mouse fibroblast cells in culture. These findings indicate that pungent diarylheptanoids from A. oxyphylla have anti-tumor promotional properties that can contribute to their chemopreventive potential.

New experimental and computational approaches to the analysis of gene expression

Public and private EST (Expressed Sequence Tag) programs provide access to a large number of ESTs from a number of plant species, including Arabidopsis, corn, soybean, rice, wheat. In addition to the homology of each EST to genes in GenBank, information about homology to all other ESTs in the data base can be obtained. To estimate expression levels of genes represented in the DuPont EST data base we count the number of times each gene has been seen in different cDNA libraries, from different tissues, developmental stages or induction conditions. This quantitation of message levels is quite accurate for highly expressed messages and, unlike conventional Northern blots, allows comparison of expression levels between different genes. Lists of most highly expresses genes in different libraries can be compiled. Also, if EST data is available for cDNA libraries derived from different developmental stages, gene expression profiles across development can be assembled. We present an example of such a profile for soybean seed development. Gene expression data obtained from Electronic Northern analysis can be confirmed and extended beyond the realm of highly expressed genes by using high density DNA arrays. The ESTs identified as interesting can be arrayed on nylon or glass and probed with total labeled cDNA first strand from the tissue of interest. Two-color fluorescent labeling allows accurate mRNA ratio measurements. We are currently using the DNA array technology to study chemical induction of gene expression and the biosynthesis of oil, carbohydrate and protein in developing seeds.

The changing landscape of ischaemic brain injury mechanisms

Thrombolysis has become established as an acute treatment for human stroke. But despite multiple clinical trials, neuroprotective strategies have yet to be proved effective in humans. Here we discuss intrinsic tissue mechanisms of ischaemic brain injury, and present a perspective that broadening of therapeutic targeting beyond excitotoxicity and neuronal calcium overload will be desirable for developing the most effective neuroprotective therapies.

Neurokinin-3 receptor distribution in rat and human brain: an immunohistochemical study

Autoradiographic and immunohistochemical studies have shown that the neurokinin-3 receptor is widely distributed in the rodent CNS. Expression of the neurokinin-3 receptor in human brain, however, has been debated. These conflicting findings, as well as the poor resolution of autoradiographic images, prompted us to develop a polyclonal antibody against an oligopeptide derived from the carboxy-terminus consensus sequence of both the rat and human neurokinin-3 receptor ([C]ASTTSSFISSPYTSVDEYS, amino acids 434-452 of the rat neurokinin-3 receptor). Western blot analysis of both human and rat brain tissue revealed a major band in the molecular weight range 65,000-67,000, the proposed molecular weight of the neurokinin-3 receptor based on its amino acid sequence and presumed glycosylation state. The distribution of selective high affinity neurokinin-3 receptor agonist [3H]senktide binding and neurokinin-3 receptor immunoreactivity were virtually identical in the brains of male Fischer 344 rats. The highest concentrations of neurokinin-3 receptors were observed in cortical layers IV-V; the basolateral amygdaloid nucleus; the hypothalamic paraventricular, perifornical and supraoptic nuclei; the zona incerta; and the entopeduncular and interpeduncular nuclei. [3H]senktide binding and neurokinin-3 receptor immunoreactivity were compared in homologous cortical areas of the human and rat brain. In contrast to the rat, autoradiographic analysis of normal control human brains (35-75 years) revealed a distinct and predominant superficial cortical labeling in the glia limitans and the cortical layer I. However, neurokinin-3 receptor immunoreactivity could be found not only in the superficial cortical layers, but also on pyramidal neurons and astrocytes in the neuropil and white matter. These findings suggest species differences in both the cellular and anatomical distribution of the neurokinin-3 receptor.

Japanese encephalitis in north Queensland, Australia, 1998

OBJECTIVE

To describe the circumstances of two cases of Japanese encephalitis (JE) in north Queensland in 1998, including one acquired on the Australian mainland.

DESIGN

Serological surveillance of sentinel pigs for JE virus activity; serological surveys of humans and pigs and viral cultures of mosquito collections.

SETTING

Islands in the Torres Strait and communities in the Northern Peninsula Area (NPA) and near the mouth of the Mitchell River in Cape York, Queensland, in the 1998 wet season (December 1997-May 1998).

RESULTS

Sentinel pigs in the Torres Strait began to seroconvert to JE virus in February 1998, just before onset of JE in an unvaccinated 12-year-old boy on Badu island. By mid-April, most sentinel pigs had seroconverted. Numerous JE viruses were isolated from Culex annulirostris mosquitoes collected on Badu. In early March, a person working at the mouth of the Mitchell River developed JE. Serological surveys showed recent JE virus infection in 13 young pigs on a nearby farm, but not in 488 nearby residents. In NPA communities, sentinel pigs seroconverted slowly and JE viruses were isolated from three, but none of 604 residents showed evidence of recent infection. Nucleotide sequencing showed that 1998 JE virus isolates from the Torres Strait were virtually identical not only to the 1998 isolate from an NPA pig, but also to previous (1995) Badu isolates.

CONCLUSIONS

JE virus activity was more widespread in north Queensland in the 1998 wet season than in the three previous wet seasons, but ecological circumstances (e.g., less intensive pig husbandry, fewer mosquitoes) appear to have limited transmission on the mainland. Nucleotide sequencing indicated a common source for the 1995 and 1998 JE viruses. Circumstantial evidence suggests that cyclonic winds carried infected mosquitoes from Papua New Guinea.

Cell cycle arrest in endometrial carcinoma cells exposed to gonadotropin-releasing hormone analog

Gonadotropin-releasing hormone (GnRH) has been shown to have an inhibitory effect on the growth of several hormone-dependent human tumors. We have treated a human endometrial cancer cell line which expresses GnRH receptor with GnRH analog, D-Trp6-LHRH, in order to study whether there are differences in cell cycle kinetic response. Flow cytometric analysis revealed that cultured carcinoma cells showed a cell cycle arrest at the G1-S transition after treatment with 10 microM D-Trp6-LHRH for 36 h. Western blot analysis showed that the level of p16 protein was obvious following 24 h of D-Trp6-LHRH treatment. These results suggest that the mechanism by which GnRH inhibits the growth of endometrial carcinoma cells may include effects on cell cycle arrest.