Analyses of mutation and loss of heterozygosity of coding sequences of the entire transforming growth factor beta type II receptor gene in sporadic human gastric cancer

Mutations in the transforming growth factor beta type II receptor (TGFbetaRII) gene have been detected in several human cancer types exhibiting microsatellite instability. Using intron primers previously reported for examination of the entire coding region of the TGFbetaRII gene, 29 sporadic gastric cancers were screened with non-radioactive single strand conformation polymorphism and subsequent DNA sequencing analysis. Mutations of the TGFbetaRII gene were detected in three out of 29 tumors (10%). Two cases showed deletions in a polyadenine tract in both alleles and was positively associated with replication error. One case had an insertion of GA dinucleotide sequence in one allele. Mutations of the TGFbetaRII gene were restricted to exon 3 and other coding regions were not affected. Loss of heterozygosity was detected by analyzing a polymorphic site in intron 2. Three out of nine (33%) informative cases, which were all of intestinal type and advanced cases, showed loss of heterozygosity but neither TGFbetaRII mutation nor replication error was found in these cases. Immunoreactivity of TGFbetaRII in tumor tissues was reduced to a different extent in the gastric cancer with genetically abnormal transforming growth factor. Although the numbers studied are small, homozygous (A)10 deletion or loss of heterozygosity of TGFbetaRII is involved in tumorigenesis and progression of at least some part of sporadic gastric cancer.      

The duration of phorbol-inducible ErbB2 tyrosine dephosphorylation parallels that of receptor endocytosis rather than threonine-686 phosphorylation: implications for the physiological role of protein kinase C in growth factor receptor signalling

Tumour cell growth may be accelerated by protein kinase C (PKC) agonists such as phorbol esters and receptor tyrosine kinases, but receptor tyrosine kinases are in turn desensitized to growth factors by PKC agonists. To clarify this apparent PKC bifunctionality, we have used phosphoantibodies to determine the relationship between PKC- dependent phosphorylation events affecting the ErbB2 oncoprotein in G8/DHFR 3T3 cells. Neither the kinetics nor the extent of phorbol- induced juxtamembrane domain (Thr686) phosphorylation vary directly with C-terminal (Tyr1222) dephosphorylation, with Tyr1222 continuing to be dephosphorylated long after Thr686 phosphorylation has also declined. Platelet-derived growth factor (PDGF) mimics the short-term effects of phorbol on Thr686 and Tyr1222 phosphorylation, and confocal microscopy reveals that both of these PKC agonists induce rapid internalization of PKC-modified ErbB2. Phorbol causes sustained cytoplasmic accumulation of PKC-phosphorylated receptors, however, whereas PDGF triggers the appearance of this ErbB2 subset only briefly. Metabolic labelling and co-precipitation studies fail to implicate heterologous molecules in either the tyrosine dephosphorylation or internalization of PKC-modified ErbB2. Taken in the context of earlier juxtamembrane domain mutagenesis studies, these findings indicate that phorbol-activated PKC may desensitize growth factor receptors to extracellular ligands solely by triggering sustained receptor internalization. We submit that PKC-dependent juxtamembrane domain phosphorylation represents a physiological mechanism for shortening the duration and enhancing the specificity of growth factor signalling by promoting internalization of liganded and unliganded receptors, respectively.      

Intracranial chondroma of the occipital lobe

A case report of an intracranial chondroma is discussed with emphasis on magnetic resonance imaging.     

The management of lymph node metastasis from bladder cancer.

AIM: The presence of pelvic lymph node metastasis from bladder cancer has traditionally been associated with a very poor prognosis. The aim of this paper is to review the literature with regard to the management of patients with nodal disease, particularly gross nodal metastasis and suggest a strategy for management of these patients. METHODS: We performed a literature search in the PubMed database and the reference lists of relevant papers describing the management of locally advanced bladder cancer. FINDINGS: There are no randomised studies relating specifically to the management of nodal metastasis in bladder cancer. It is clear however that a significant number of patients with micrometastatic nodal disease may be cured. Few studies exist which address the management of patients with gross nodal disease and consist of series from a limited number of institutions. In patients with gross nodal disease detected pre-operatively or at the time of surgery, a multimodality approach consisting of surgery, chemotherapy and possibly radiotherapy seems appropriate. The prognosis of such patients relates to the pathological stage of the primary tumour and the degree of lymph node involvement. In addition a good response to neoadjuvant chemotherapy may identify patients who are likely to survive longer. CONCLUSIONS: The prognosis for patients with gross nodal disease from bladder cancer is poor although cure may be possible in a small number of patients. In such cases a multimodality approach is appropriate and management decisions should be made on an individual patient basis.     

Evidence for re-infection and persistent carriage of Shigella species in adult males reporting domestically acquired infection in England

ObjectivesWe analysed national surveillance typing data of Shigella isolated from adult males with domestically acquired infection (a cohort largely consisting of men who have sex with men (MSM)) to establish whether multiple isolates from the same individual over time represented persistent carriage or re-infection.MethodsWe carried out a retrospective cohort study of adult males diagnosed with Shigella from 2004 to 2018. Median time intervals between multiple isolations of Shigella flexneri and S. sonnei were compared. Analysis of whole genome sequencing data provided strain discrimination at the single nucleotide level and was used to quantify the genetic distance among isolates. Maximum likelihood phylogenies were constructed to determine whether persistent carriage (characterized by multiple isolations of the same strain) or re-infection (characterized by multiple isolations of different strains) was best supported by the phylogenetic analysis. A comparison analysis was carried out using data linked to adult females with domestically acquired shigellosis.ResultsThe number of men reporting multiple isolations of Shigella species was 165/4733 (3.5%) compared with 31/2423 (1.3%) females (p < 0.001). For isolate pairs from men associated with persistent carriage, the isolation time interval range was 6–176 days (median 23.5; IQR 8–70) and single nucleotide polymorphism (SNP) distance range was 0–7 SNPs (median 0.5; IQR 0–2). For those associated with re-infection, the isolation time interval was 34–2636 days (median 732; IQR 191–1258) and the SNP distance was 10–1462 SNPs (median 120; IQR 29–377).DiscussionMultiple Shigella isolations in individuals with domestically acquired infections was more frequently observed in adult males than in adult females. Following the acute phase of infection, carriage can persist for months, and infection can recur within months, even with strains belonging to the same species and the same serotype. A combination of multiple sexual partners, persistent carriage following the acute phase of infection and evidence of recurrent re-infection is likely to contribute to sustained transmission in this population.     

Mifepristone in the Central Nucleus of the Amygdala Reduces Yohimbine Stress-Induced Reinstatement of Ethanol-Seeking

Chronic ethanol exposure leads to dysregulation of the hypothalamic-pituitary-adrenal axis, leading to changes in glucocorticoid release and function that have been proposed to maintain pathological alcohol consumption and increase vulnerability to relapse during abstinence. The objective of this study was to determine whether mifepristone, a glucocorticoid receptor antagonist, plays a role in ethanol self-administration and reinstatement. Male, Long–Evans rats were trained to self-administer either ethanol or sucrose in daily 30 min operant self-administration sessions using a fixed ratio 3 schedule of reinforcement. Following establishment of stable baseline responding, we examined the effects of mifepristone on maintained responding and yohimbine-induced increases in responding for ethanol and sucrose. Lever responding was extinguished in separate groups of rats and animals were tested for yohimbine-induced reinstatement and corticosterone release. We also investigated the effects of local mifepristone infusions into the central amygdala (CeA) on yohimbine-induced reinstatement of ethanol- and sucrose-seeking. In addition, we infused mifepristone into the basolateral amygdala (BLA) in ethanol-seeking animals as an anatomical control. We show that both systemic and intra-CeA (but not BLA) mifepristone administration suppressed yohimbine-induced reinstatement of ethanol-seeking, while only systemic injections attenuated sucrose-seeking. In contrast, baseline consumption, yohimbine-induced increases in responding, and circulating CORT levels were unaffected. The data indicate that the CeA plays an important role in the effects of mifepristone on yohimbine-induced reinstatement of ethanol-seeking. Mifepristone may be a valuable pharmacotherapeutic strategy for preventing relapse to alcohol use disorders and, as it is FDA approved, may be a candidate for clinical trials in the near future.     

Phosphorylation of factor Va and factor VIIIa by activated platelets

Platelet activation leads to the incorporation of 32[PO4(2-)] into bovine coagulation factor Va and recombinant human factor VIII. In the presence of the soluble fraction from thrombin-activated platelets and (gamma-32P) adenosine triphosphate, radioactivity is incorporated exclusively into the M(r) = 94,000 heavy chain (H94) of factor Va and into the M(r) = 210,000 to 90,000 heavy chains as well into the M(r) = 80,000 light chain of factor VIII. Proteolysis of the purified phosphorylated M(r) = 94,000 factor Va heavy chain by activated protein C (APC) gave products of M(r) = 70,000, 24,000, and 20,000. Only the intermediate M(r) = 24,000 fragment contained radioactivity. Because the difference between the M(r) = 24,000 and M(r) = 20,000 fragments is located on the COOH-terminal end of the bovine heavy chain, phosphorylation of H94 must occur within the M(r) = 4,000 peptide derived from the carboxyl-terminal end of H94 (residues 663 through 713). Exposure of the radioactive factor VIII molecule to thrombin ultimately resulted in a nonradioactive light chain and an M(r) = 24,000 radioactive fragment that corresponds to the carboxyl-terminal segment of the A1 domain of factor VIII. Based on the known sequence of human factor VIII, phosphorylation of factor VIII by the platelet kinase probably occurs within the acidic regions 337 through 372 and 1649 through 1689 of the procofactor. These acidic regions are highly homologous to sequences known to be phosphorylated by casein kinase II. Results obtained using purified casein kinase II gave a maximum observed stoichiometry of 0.6 mol of 32[PO4(2-)]/mol of factor Va heavy chain and 0.35 mol of 32[PO4(2-)]/mol of factor VIII. Phosphoamino acid analysis of phosphorylated factor Va by casein kinase II or by the platelet kinase showed only the presence of phosphoserine while phosphoamino acid analysis of phosphorylated factor VIII by casein kinase II showed the presence of phosphothreonine as well as small amounts of phosphoserine. The platelet kinase responsible for the phosphorylation of the two cofactors was found to be inhibited by several synthetic protein kinase inhibitors. Finally, partially phosphorylated factor Va was found to be more sensitive to APC inactivation than its native counterpart. Our findings suggest that phosphorylation of factors Va and VIIIa by a platelet casein kinase II- like kinase may downregulate the activity of the two cofactors.