A canine model for the study of hapten-specific suppression of IgE-mediated bronchoconstriction and anaphylaxis

Newborn mongrel dogs were sensitized with conjugates of ovalbumin (OA) and 2,4-dinitrophenol (OA-DNP3) in the presence of Al(OH)3 to produce high levels of anti-OA and anti-DNP IgE antibody. At 4-6 months of age, when anti-DNP and anti-OA antibody levels reached titers of 64 by passive cutaneous anaphylaxis, the dogs underwent separate inhalation and intravenous challenges with conjugates of DNP and bovine gamma globulin (DNP15-BGG) and OA. Inhalation challenge with DNP15-BGG and OA resulted in 5- and 10-fold increases in airflow resistance, respectively. Intravenous challenge with either DNP15-BGG or OA produced profound anaphylaxis with 60-80% decreases in blood pressure, cardiac output and regional blood flows in the carotid, superior mesenteric and renal arteries, and the distal aorta. Treatment of sensitized dogs with 5 doses of 20 mg of conjugates of DNP and polyvinyl alcohol (DNP2-PVA) on alternate days resulted in suppression of anti-DNP IgE antibody production; abrogation of established airway and vascular anaphylactic sensitivities; no change in regional blood flows, and no effect on sensitivities to challenge with OA.     

PTEN mutational spectra,expression levels,and subcellular localization in microsatellite stable and unstable colorectal cancers

PTEN on 10q23.3 encodes a dual-specificity phosphatase that negatively regulates the phosphoinositol-3-kinase/Akt pathway and mediates cell-cycle arrest and apoptosis. Germline PTEN mutations cause Cowden syndrome and a range of several different hamartoma-tumor syndromes. Hereditary nonpolyposis colon cancer (HNPCC) syndrome is characterized by germline mutations in the mismatch repair (MMR) genes and by microsatellite instability (MSI) in component tumors. Although both colorectal carcinoma and endometrial carcinoma are the most frequent component cancers in HNPCC, only endometrial cancer has been shown to be a minor component of Cowden syndrome. We have demonstrated that somatic inactivation of PTEN is involved in both sporadic endometrial cancers and HNPCC-related endometrial cancers but with different mutational spectra and different relationships to MSI. In the current study, we sought to determine the relationship of PTEN mutation, 10q23 loss of heterozygosity, PTEN expression, and MSI status in colorectal cancers (CRCs). Among 11 HNPCC CRCs, 32 MSI+ sporadic cancers, and 39 MSI- tumors, loss of heterozygosity at 10q23.3 was found in 0%, 8%, and 19%, respectively. Somatic mutations were found in 18% (2 of 11) of the HNPCC CRCs and 13% (4 of 32) of the MSI+ sporadic tumors, but not in MSI- cancers (P = 0.015). All somatic mutations occurred in the two 6(A) coding mononucleotide tracts in PTEN, suggestive of the etiological role of the deficient MMR. Immunohistochemical analysis revealed 31% (14 of 45) of the HNPCC CRCs and 41% (9 of 22) of the MSI+ sporadic tumors with absent or depressed PTEN expression. Approximately 17% (4 of 23) of the MSI- CRCs had decreased PTEN expression, and no MSI- tumor had complete loss of PTEN expression. Among the five HNPCC or MSI+ sporadic CRCs carrying frameshift somatic mutations with immunohistochemistry data, three had lost all PTEN expression, one showed weak PTEN expression levels, and one had mixed tumor cell populations with weak and moderate expression levels. These results suggest that PTEN frameshift mutations in HNPCC and sporadic MSI+ tumors are a consequence of mismatch repair deficiency. Further, hemizygous deletions in MSI- CRCs lead to loss or reduction of PTEN protein levels and contribute to tumor progression. Finally, our data also suggest that epigenetic inactivation of PTEN, including differential subcellular compartmentalization, occurs in CRCs.     

Mechanical heart valve prostheses:: identification and evaluation (erratum)

Mechanical heart value prostheses have been in use since the 1950s. Many prostheses have been used for a while and then discontinued. Today, there are a large number and variety of prostheses in use and an even larger variety that are in place in patients. These may be explanted at any time for a number of reasons. It is essential for the practicing pathologist to be able to identify the prosthesis and be aware of some of its reported complications and modes of failure. This article, and a second one on bioprosthetic heart valves, is designed as a ready reference guide to heart valve prostheses, their important identifying features, their common complications, and modes of failure. It should help in the accurate identification of explanted prosthetic valves and more definitive reports. This accuracy of identification as well as tracking of abnormalities noted will, we hope, permit the identification of new failure modes and the recording of causes of failure of new (or even modified) prosthetic heart valves.     

Polymorphisms in the MAOA, MAOB, and COMT genes and aggressive behavior in schizophrenia.

Some studies have reported associations between COMT and MAO genotypes and aggression, though results have been inconsistent. We examined the relationship between Overt aggression scale (OAS) scores, and both MAOA and MAOB polymorphisms in a well-powered sample of 346 subjects with schizophrenia. We also examined COMT in a Stage II replication sample of 150 individuals, and combined these results with our previously reported (Stage I) findings for COMT. We found no evidence of any associations between OAS ratings and any of the polymorphisms investigated under different genetic models. There was no evidence of epistatic interaction between MAOA and COMT on OAS scores. These results fail to support the theory that functional polymorphisms within the MAOA, MAOB, or COMT genes, as determinants of catecholamine enzymatic activity, are risk factors for aggressive behavior.     

A canine model for reaginic hypersensitivity and allergic bronchoconstriction

Immunization of neonatal dogs with a conjugate of 2,4-dinitrobenzene and ovalbumin (DNP₂-OA), using aluminum hydroxide as the adjuvant, elicited long-lasting (over 30 wk) anti-DNP and anti-OA IgE antibody responses of high titers as determined by homologous passive cutaneous anaphylaxis. Low antigen doses of 10 or 50 μg were more effective than the higher doses of 250 or 1,250 μg in inducing high IgE antibody levels. However, this method of immunization failed to elicit any detectable IgE antibody response in adult dogs. Bronchoprovocation with antigen of sensitized animals having IgE antibody titers in excess of 64 resulted in a marked increase in airflow resistance, which could be corrected by the administration of nebulized isoproterenol. On the other hand, sensitized animals with IgE antibody titers in the order of 64 did not manifest significant bronchoconstriction on inhalation challenge but developed anaphylaxis following intravenous injection of the antigen.     

Management of unruptured incidentally found intracranial saccular aneurysms

Neurosurgical Review - Unruptured intracranial saccular aneurysms occur in 3–5% of the general population. As the use of diagnostic medical imaging has steadily increased over the past few...     

Large‐scale bone mineral histomorphometry – report of a simplified technique

Karantzoulis V, Liapi C & Papaggelopoulos P
(2012) Histopathology
Large‐scale bone mineral histomorphometry – report of a simplified technique Aims: The aim of this study was the development of a simplified technique for bone mineral histomorphology on large undecalcified bone samples. Established techniques, such as undecalcified bone thin sectioning, ultrathin grinding, surface‐stained block grinding and micro‐computerized tomography (CT), are expensive, time‐consuming and put very high demands on equipment, safety standards, personnel and laboratory facilities. Methods and results: The method is based on the surface‐stained block‐grinding principle; however, its novelty lies in the selection of user‐friendly, safe and low‐cost materials, equipment and digitization techniques. We describe in detail the relevant steps, as well as many practical tips for their successful implementation: accurate bone cutting in thin sections with a customized arrangement on a commercial bandsaw, defatting with sodium hypochlorite, embedding in epoxy resin blocks at room temperature, silicon carbide paper grinding, von Kossa staining, flatbed scanner digitization and image processing. Conclusion: We believe that the proposed methodology could contribute to the expansion of the study of bone tissue, as it enables the rapid examination of bone specimens on a large scale with minimal laboratory requirements and consumables costs.     

Biochemical screening and PTEN mutation analysis in individuals with autism spectrum disorders and macrocephaly

Unlike some other childhood neurodevelopmental disorders, no diagnostic biochemical marker has been identified in all individuals with an autism spectrum disorder (ASD). This deficit likely results from genetic heterogeneity among the population. Therefore, we evaluated a subset of individuals with ASDs, specifically, individuals with or without macrocephaly in the presence or absence of PTEN mutations. We sought to determine if amino or organic acid markers could be used to identify individuals with ASDs with or without macrocephaly in the presence or absence of PTEN mutations, and to establish the degree of macrocephaly in individuals with ASDs and PTEN mutation. Urine, blood and occipital–frontal circumference (OFC) measurements were collected from 69 individuals meeting DSM-IV-TR criteria. Urine and plasma samples were subjected to amino and organic acid analyses. PTEN was Sanger-sequenced from germline genomic DNA. Germline PTEN mutations were identified in 27% (6/22) of the macrocephalic ASD population. All six PTEN mutation-positive individuals were macrocephalic with average OFC+4.35 standard deviations (SDs) above the mean. No common biochemical abnormalities were identified in macrocephalic ASD individuals with or without PTEN mutations. In contrast, among the collective ASD population, elevation of urine aspartic acid (87% 54/62), plasma taurine (69% 46/67) and reduction of plasma cystine (72% 46/64) were observed. PTEN sequencing should be carried out for all individuals with ASDs and macrocephaly with OFC ≥2SDs above the mean. A proportion of individuals with ASDs may have an underlying disorder in sulfur amino acid metabolism.