A rete mirabile of the posterior cerebral artery. Embryonic and phylogenetic remnant of choroidal artery origin

SUMMARY

We present the case of a 41-year-old man with a vascular network associated with the left posterior cerebral artery (PCA). Although initially considered to be a brain AVM, further investigation showed no arteriovenous shunting and a rete mirabile of the PCA was diagnosed. A well known but rare occurrence mainly in the anterior circulation, rete mirabile has not previously been described in the PCA.The PCA is a composite vessel, developmentally. Its proximal portion derives from the posterior division of the ICA while its cortical territories are annexed from the anterior choroidal artery adjacent to the lateral geniculate body. We propose that this rete (or network) represents a persistence of the embryonic anastomosis betweenthe AChA and the PCA.

Prevalence of and risk factors for isolated systolic hypertension in the rural adult population of Liaoning Province, China

The prevalence of and associated risk factors for isolated systolic hypertension, as defined by the Joint National Committee (JNC)-6 classification, were investigated in the rural population of Liaoning Province, China. A total of 45,925 people aged 35 years or older were examined in a cross-sectional study. Overall, the prevalence of isolated systolic hypertension was 10.6% (males 10.1%; females 11.2%). The prevalence of isolated systolic hypertension was positively correlated with age, gender, smoking status, alcohol intake, body mass index, salt intake and Mongolian race. This study showed that isolated systolic hypertension was very common in rural Chinese people and that many risk factors are linked with isolated systolic hypertension.

Expression of anion exchanger 2 in human gastric cancer

Anion exchanger 2 (AE2), which mediates exchange of Cl(-)/HCO3(-) across the plasma membrane, is widely expressed in body tissues. It is most abundantly expressed in stomach and is responsible for the uptake of Cl(-) ions that are destined to become HCl molecules.

AIM

To determine whether AE2 expression was altered in gastric tumors.

METHODS

We have studied AE2 expression in normal human gastric tissues (n =16) and in gastric tumors (n = 33) using immunohistochemistry and immunofluorescent labeling.

RESULTS

In normal gastric tissue positive staining was observed in gastric fundus gland, suggesting parietal cell-related expression of AE2, and AE2 expression was localized in the nuclear membrane and even in cell nuclei. For assay of cancerous gastric tissues, specimens of human gastric cancer arising from the region of the fundus (2 cases), the body (14 cases) and the antrum (17 cases) were randomly selected. Immunohistochemical staining has showed that AE2 was down-regulated in all 14 cancerous gastric body specimens, whereas staining for AE2 in cancerous antrum was less intense and had a diffuse profile.

CONCLUSIONS

The data suggest that AE2 might be associated with gastric carcinogenesis and the achlorhydria experienced by gastric cancer patients.

Accumulating variation at conserved sites in potyvirus genomes is driven by species discovery and affects degenerate primer design

Unknown and foreign viruses can be detected using degenerate primers targeted at conserved sites in the known viral gene sequences. Conserved sites are found by comparing sequences and so the usefulness of a set of primers depends crucially on how well the known sequences represent the target group including unknown sequences.

Methodology/Principal Findings

We developed a method for assessing the apparent stability of consensus sequences at sites over time using deposition dates from Genbank. We tested the method using 17 conserved sites in potyvirus genomes. The accumulation of knowledge of sequence variants over 20 years caused ‘consensus decay’ of the sites. Rates of decay were rapid at all sites but varied widely and as a result, the ranking of the most conserved sites changed. The discovery and reporting of sequences from previously unknown and distinct species, rather than from strains of known species, dominated the decay, indicating it was largely a sampling effect related to the progressive discovery of species, and recent virus mutation was probably only a minor contributing factor.

Conclusion/Significance

We showed that in the past, the sampling bias has misled the choice of the most conserved target sites for genus specific degenerate primers. The history of sequence discoveries indicates primer designs should be updated regularly and provides an additional dimension for improving the design of degenerate primers.

Altered hippocampal circuit function in C3H alpha7 null mutant heterozygous mice

The alpha7 subtype of nicotinic receptor is highly expressed in the hippocampus where it is purported to modulate release of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). The alpha7 receptor-mediated release of GABA is thought to contribute to hippocampal inhibition (gating) of response to repetitive auditory stimulation. This hypothesis is supported by observations of hippocampal auditory gating deficits in mouse strains with low levels of hippocampal alpha7 receptors compared to strains with high levels of hippocampal alpha7 receptors. The difficulty with comparisons between mouse strains, however, is that different strains have different genetic backgrounds. Thus, the observed interstrain differences in hippocampal auditory gating might result from factors other than interstrain variations in the density of hippocampal alpha7 receptors. To address this issue, hippocampal binding of the alpha7 receptor-selective antagonist alpha-bungarotoxin as well as hippocampal auditory gating characteristics were compared in C3H wild type and C3H alpha7 receptor null mutant heterozygous mice. The C3H alpha7 heterozygous mice exhibited significant reductions in hippocampal alpha7 receptor levels and abnormal hippocampal auditory gating compared to the C3H wild type mice. In addition, a general increase in CA3 pyramidal neuron responsivity was observed in the heterozygous mice compared to the wild type mice. These data suggest that decreasing hippocampal alpha7 receptor density results in a profound alteration in hippocampal circuit function.

Prevalence of metabolic syndrome in Han and Mongolian rural population with hypertension

The prevalence of metabolic syndrome, as defined by the International Diabetes Federation, was compared in two rural populations with hypertension in China. A total of 6326 subjects aged >or= 35 years were included: 5043 Han and 1283 Mongolian. Metabolic syndrome was identified in 33.9% (men: 16.1%; women: 47.8%) of the Han and 37.6% (men: 14.7%; women: 55.0%) of the Mongolian populations. In men, prevalence of metabolic syndrome showed no obvious ethnicity differences; however, in women, prevalence was significantly higher in the Mongolian than in the Han population. This study showed high prevalence and ethnic differences in prevalence of metabolic syndrome in these two Chinese hypertensive populations.

Critical role of inducible nitric oxide synthase in degeneration of retinal capillaries in mice with streptozotocin-induced diabetes

AIMS/HYPOTHESIS

Diabetes results in the upregulation of the production of several components of the inflammatory response in the retina, including inducible nitric oxide synthase (iNOS). The aim of this study was to investigate the role of iNOS in the pathogenesis of the early stages of diabetic retinopathy using iNOS-deficient mice (iNos (-/-)).

MATERIALS AND METHODS

iNos (-/-) mice and wild-type (WT; C57BL/6J) mice were made diabetic with streptozotocin or kept as non-diabetic controls. Mice were killed at different time points after the induction of diabetes for assessment of vascular histopathology, cell loss in the ganglion cell layer (GCL), retinal thickness, and biochemical and physiological abnormalities.

RESULTS

The concentrations of nitric oxide, nitration of proteins, poly(ADP-ribose) (PAR)-modified proteins, endothelial nitric oxide synthase, prostaglandin E(2), superoxide and leucostasis were significantly (p < 0.05) increased in retinas of WT mice diabetic for 2 months compared with non-diabetic WT mice. All of these abnormalities except PAR-modified proteins in retinas were inhibited (p < 0.05) in diabetic iNos (-/-) mice. The number of acellular capillaries and pericyte ghosts was significantly increased in retinas from WT mice diabetic for 9 months compared with non-diabetic WT controls, these increases being significantly inhibited in diabetic iNos (-/-) mice (p < 0.05 for all). Retinas from WT diabetic mice were significantly thinner than those from their non-diabetic controls, whereas diabetic iNos (-/-) mice were protected from this abnormality. We found no evidence of cell loss in the GCL of diabetic WT or iNos (-/-) mice. Deletion of iNos had no beneficial effect on diabetes-induced abnormalities on the electroretinogram.

CONCLUSIONS/INTERPRETATION

We demonstrate that the inflammatory enzyme iNOS plays an important role in the pathogenesis of vascular lesions characteristic of the early stages of diabetic retinopathy in mice.

A phase II trial of weekly cisplatin and docetaxel in advanced non-small cell lung cancer (NSCLC)

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Background: Every 3-week cisplatin doublets used to treat advanced NSCLC carry a significant risk of renal and other toxicities and can be difficult for patients with co-morbidities. To reduce these toxicities, we conducted a phase II study to evaluate the efficacy and toxicity of weekly cisplatin and docetaxel in advanced NSCLC. Methods: Eligibility included patients with advanced or recurrent NSCLC, ECOG PS of 0–1, and no prior chemotherapy for metastatic disease. This Cancer Institute of New Jersey network, single stage phase II clinical trial was designed to give 3 weekly doses of cisplatin at 25 mg/m2 and docetaxel at 35 mg/m2, followed by 1 week of rest, for a total of 6 cycles of therapy. Toxicity was monitored weekly, and disease evaluation was performed every 2 cycles. The primary endpoint was response rate (RR); secondary endpoints included time to progression (TTP), median and 1-year survival. Results: From 12/03 to 11/06, 36 patients were enrolled so far. The median age of patients is 63 (range 47–78), the majority is white (n=33), 29 have stage IV disease, and half (n=18) are women. Fourteen have an ECOG PS=0 and 22 with PS=1. Histologic subtypes are: adenocarcinoma (n=24), NSCLC NOS (n=7), squamous (n=5). Eleven patients received = 4 cycles of therapy; median number of cycles delivered is 2.5. Reasons for treatment discontinuation include completion of therapy (n=5), progression of disease (n=16), adverse events (n=8), and patient preference (n=4). Three patients continue on therapy at this time. No complete responses were yet observed; 8 patients (22%) achieved a partial response; 10 patients had stable disease, 10 patients progressed, and 8 came off study before first disease evaluation. Median TTP was 3.1 months (mo) (95% CI 2, 5.5), median survival is 8.3 mo (95% CI 5,16.2) and 1-year survival is 39% (95% CI 20, 57). Most toxicities were mild but also included neutropenia (grade 3, n=1; grade 4, n=1), neutropenic fever (n=1), renal toxicity (grade 3, n=2), nausea (grade 3, n=1), fatigue (grade 3, n=3), diarrhea (grade 3, n=4) and metabolic abnormalities (grade 3, n=3). Conclusion: Weekly cisplatin and docetaxel is well tolerated with a low incidence of toxicity and demonstrates activity similar to every 3-week treatment in patients with advanced NSCLC.

No significant financial relationships to disclose.

Randomized multicenter phase III trial of oxaliplatin plus raltitrexed compared to oxaliplatin plus fluorouracil and leucovorin treatment in recurrent and metastatic colorectal cancer

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Purpose: To compare oxaliplatin (L-OHP) plus raltitrexed (RTX) with L-OHP plus fluorouracil and leucovorin (LV/5FU) for patients (pts) with recurrent and metastatic colorectal cancer(CRC). Methods: Eligible pts had to have histologically proven recurrent or metastatic CRC,not having previously received oxaliplatin as palliative chemotherapy,ECOG PS = 2,age:18∼70,and adequate hematological,renal and hepatic function.After written informed consent,pts were randomized to L-OHP:130 mg/m2 d1 + RTX: 3 mg/m2 d1 (Arm A) or + LV: 200 mg/m2 + 5FU:375 mg/m2 d1–5 (Arm B). Results: Between Jan 2005 and July 2006, 216 pts were enrolled at 15 centers in China.112 pts (mean age: 55.0 (19∼70), M/F: 57/46, PS 0/1/2: 46/53/13) were randomly assigned to A and 102 (mean age: 54.2(22∼70), M/F: 54/46, PS 0/1/2: 44/59/9) to B. 203 pts were eligible for response evaluation (A:103, B:100).The median number of cycles was 4 (1∼6) in A and 3 (1∼6) in B (P=0.1431).The RR was 29.1% (CR:2, PR:28, SD:50 , PD:23) in A and 17.0% (CR:2, PR:15, SD:46 , PD:37) in B (P=0.0437).The disease-control rate was 77.7% in A and 63.0% in B (P=0.0237). After a median follow-up of 10 months (4–16.5),92 pts had had progression of disease (40 in A and 52 in B); 73 deaths had occurred (35 in A and 38 in B), median time to progression was not reached. Following-up is ongoing.The median QoL scores for the two arms were comparable. 214 were included in the safety analyses (A:112, B:102). There was a higher incidence of neutropenia (48.2% verse 29.4%, P=0.005) and transaminase increase (49.1% verse 35.3%, P=0.041) among A. Grade 3 or 4 neutropenia was much common in pts in A than those in B (20.5% verse 4.9% , P=0.001), but was complicated by fever in only 3.6% of cases (4 pts) in A and in 2.9% of cases (3 pts) in B. No pts were dead or infectious due to neutropenia. There were similar rates of grade 3 or 4 transaminase elevation in the two groups. Vomitting and anorexia were much commoner with B. Conclusions: The L-OHP+RTX seems beneficial in recurrent and metastatic CRC, demonstrating better response rate and higher disease control rate with acceptable tolerability, maintenance of QoL and convenient administration schedule.

No significant financial relationships to disclose.

Construction of a counterselection-based in-frame deletion system for genetic studies of Streptococcus mutans

Genetic studies of Streptococcus mutans have benefited greatly from the numerous techniques that have been successfully adapted for use in this organism. One notable exception is the lack of a negative selection system that can be employed for the easy isolation of markerless in-frame deletions. In this study, we report the development of a galK/galactose-based negative selection system in S. mutans for this purpose. This system consists of a recipient strain (IFD140) that contains a deletion in the galKTE operon and a suicide vector (pIFD-Sm) that carries the S. mutans galK open reading frame fused to the constitutive lactate dehydrogenase (ldh) promoter. Using this system we created a markerless in-frame deletion in the beta-galactosidase (lacG) gene within the S. mutans lactose operon. After vector integration, plasmid excision after counterselection appeared to have occurred in 100% of the galactose-resistant colonies and resulted in in-frame deletions in 50% of the screened isolates. Based on the ratio of galactose-resistant cells to total cells, we determined that plasmid excision occurred at a frequency of approximately 1/3000 cells. Furthermore, the simplicity of this system should make it adaptable for use in numerous other gram-positive and gram-negative organisms.

Postsynaptic enrichment of Eps8 at dendritic shaft synapses of unipolar brush cells in rat cerebellum

Epidermal growth factor receptor pathway substrate 8 (Eps8) is a widely expressed multidomain signaling protein that coordinates two disparate GTPase-dependent mechanisms: actin reorganization via Ras/Rac pathways and receptor trafficking via Rab5. Expression of Eps8, the gene encoding the founding member of the Eps8 family of proteins, was found in cerebellum by virtual Northern analysis and in situ hybridization. Because the cerebellum has a well-known cellular architecture and is a favored model to study synaptic plasticity and actin dynamics, we sought to analyze Eps8 localization in rat cerebellar neurons and synapses by light and electron microscopy. Specificity of Eps8-antibody was demonstrated by immunoblots and in brain sections. In cerebellum, unipolar brush cells (UBCs) were densely Eps8 immunopositive and granule cells were moderately immunostained. In both types of neuron immunoreaction product was localized to the somatodendritic and axonal compartments. Postsynaptic immunostained foci were demonstrated in the glomeruli in correspondence of the synapses formed by mossy fiber terminals with granule cell and UBC dendrites. These foci appeared especially evident in the UBC brush, which contains an extraordinary postsynaptic apparatus of actin microfilaments facing synaptic junctions of the long and segmented varieties. Eps8 immunoreactivity was conspicuously absent in Purkinje cells and their actin-rich dendritic spines, in all types of inhibitory interneurons of the cerebellum, cerebellar nuclei neurons, and astrocytes. In conclusion, Eps8 protein in cerebellum is expressed exclusively by excitatory cortical interneurons and is intracellularly compartmentalized in a cell-class specific manner. This is the first demonstration of the presence of a member of the Eps8 protein family in UBCs and its enrichment at postsynaptic sites.

Novel animal models for Sjögren's syndrome: expression and transfer of salivary gland dysfunction from regulatory T cell-deficient mice

IL-2 knockout (KO), IL-2Ralpha KO and scurfy mice lack the CD4+CD25+ regulatory T (Treg) cells and develop severe inflammation in multiple organs, although organs affected vary among these strains. We asked if salivary and lacrimal glands, the main organs affected in Sjögren's syndrome, are targeted in these strains. Severe lymphocyte and neutrophil infiltration in the salivary and lacrimal glands and a decrease in salivary secretory function were observed in IL-2 KO and IL-2Ralpha KO mice, but not in scurfy mice. Interestingly, transfer of lymph node cells from scurfy mice to RAG-1 KO recipients rapidly and effectively induced inflammation and loss of function in the salivary glands. Furthermore, we observed that daily LPS feeding in scurfy mice also induced inflammation in the salivary glands. Our study demonstrates several novel models for Sjögren's syndrome, including an adoptive transfer model that shows that scurfy mice have dormant salivary gland-specific autoreactive lymphocytes that can be activated by certain environmental factors, such as those present in RAG-1 KO mice.

Expression of immune responsive genes in cell lines from two different Anopheline species

Malaria infection results in increased expression of immune responsive genes, including those encoding antimicrobial peptides such as Gambicin (Gam1) and Cecropin A (Cec1). Understanding how these genes are regulated will provide insights how the mosquito immune system is activated by Plasmodium. We previously have shown that Cec1 was primarily regulated by the Imd-Relish (REL2) pathway in the Anopheles gambiae Sua1B cell line. We show here that expression of Defensin A (Def1) and Gam1 was reduced after RNA interference against components of the Imd-REL2 pathway in An. gambiae cell lines. Interestingly, promoter reporters of these antimicrobial peptides were expressed at very low level in the cell line MSQ43 from Anopheles stephensi. Surprisingly, over-expression of either NF-kappaB transcription factor REL1 or REL2 alone is sufficient to induce the expression of Cec1, Gam1 and Def1. These results suggest that expression of these antimicrobial peptides (AMP) in vivo may be regulated by both the Toll and Imd pathways. We also show here for the first time that Tep4, a gene encoding a thioester containing protein, is regulated by REL2. Taken together, these results suggest that there are significant overlaps of genes regulated by the Toll-Rel1 and Imd-Rel2 pathways. Further, the different expression patterns in two different Anopheline cell lines provide a platform to identify other key positive and negative regulators of the antimicrobial peptide genes.

Espins and the actin cytoskeleton of hair cell stereocilia and sensory cell microvilli

The espins are novel actin-bundling proteins that are produced in multiple isoforms from a single gene. They are present at high concentration in the parallel actin bundle of hair cell stereocilia and are the target of deafness mutations in mice and humans. Espins are also enriched in the microvilli of taste receptor cells, solitary chemoreceptor cells, vomeronasal sensory neurons and Merkel cells, suggesting that espins play important roles in the microvillar projections of vertebrate sensory cells. Espins are potent actin-bundling proteins that are not inhibited by Ca2+. In cells, they efficiently elongate parallel actin bundles and, thereby, help determine the steadystate length of microvilli and stereocilia. Espins bind actin monomer via their WH2 domain and can assemble actin bundles in cells. Certain espin isoforms can also bind phosphatidylinositol 4,5-bisphosphate, profilins or SH3 proteins. These biological activities distinguish espins from other actin-bundling proteins and may make them well-suited to sensory cells.

A prospective study of respiratory ciliary structure and function after stem cell transplantation

We prospectively investigated the morphological and ciliary function abnormalities in 19 consecutive Chinese patients undergoing hemopoietic stem cell transplantation (HSCT) and studied their relationship with pulmonary complications. The percentage of structural ciliary abnormalities preceding HSCT was comparable to normal controls, but increased up to 1-year post-HSCT. However, the abnormalities did not correlate with ciliary or pulmonary function. Ciliary beat frequency (CBF) for patients undergoing autologous and allogeneic SCT was lower than that of matched controls, with a further decline at one year. There was, however, no significant change in pulmonary function for the whole cohort. There was considerable variation in CBF and ciliary abnormalities in all cases during 3-month interval assessments. Regular ciliary assessment did not predict the only two patients who eventually suffered from bronchiolitis obliterans (BO). We conclude that structural and functional ciliary abnormalities are common in recipients of HSCT, and predict post-HSCT deterioration. However, there is no evidence to show that CBF monitoring may be of prospective benefit.