Analysis on distribution and genomic diversity of high-level antiseptic resistance genes qacA and qacB in human clinical isolates of Staphylococcus aureus

High-level antiseptic resistance of Staphylococcus aureus is mediated by multidrug efflux pumps encoded by qacA and qacB genes. We investigated distribution and genomic diversity of these antiseptic resistance genes in a total of 522 clinical strains of S. aureus isolated recently in a Japanese hospital. The qacA/B gene was detected in 32.6% of methicillin-resistant S. aureus (MRSA) and 7.5% of methicillin-susceptible S. aureus (MSSA), whereas the low-level resistance gene smr, which was examined simultaneously, was detected at lower frequencies in both MRSA (3.3%) and MSSA (5.9%). Epidemiologic typing of S. aureus isolates suggested that higher prevalence of qacA/B in MRSA may be due to spread of a single predominant MRSA strain carrying qacA/B in the hospital. Restriction fragment length polymorphism (RFLP) analysis indicated higher prevalence of the qacB-type gene (59.3%) than the qacA-type gene (40.7%) among the qacA/B genes detected. Nucleotide sequencing analysis revealed the presence of two genetic variants in qacA (V1 and V2) and four variants in qacB (V1-V4) that differ from the qacA prototype in pSK1 by 1-5 nucleotides and 7-9 nucleotides, respectively. Although most strains with qacA-V1, qacA-V2, qacB-V3, and qacB-V4 showed high-level resistance to ethidium bromide (EB)(MIC > 100 microg/ml), all of the S. aureus isolates carrying qacB-V1 and qacB-V2 showed lower MICs of EB and some monovalent cationic antiseptic substances. By analysis of the genomic organization of the qacA/B downstream region, divergent forms of this region rearranged with an insertion of IS256 or IS257 were found primarily for qacB. The downstream region of qacA-V1 was suggested to be an evolutionary origin for other divergent forms. These findings indicated that both qacA and qacB are prevalent in recent clinical isolates, especially in MRSA, and these genes consist of variable genetic variants that may be responsible for different resistance levels against antiseptic substances.     

Implication of the common {gamma} chain of the IL-7 receptor in intrathymic development of pro-T cells

The effects of IL-7 on the growth and differentiation of thymocyteswere analyzed using murine fetal thymua organ cultures (FTOC)in the presence of mAbs specific for the conventional IL-7 receptor(1L-7R) and for the common (c) chain. In FTOC, the developmentof CD4^–CD8^– double-negative thymocytes to CD4+CD8+double-positive (DP) and CD4+ or CD8+ single-positive (SP) cellswas not completely blocked by adding these mAbs, although cellgrowth was reduced by the treatment. To define a developingstage sensitive to the mAbs, most immature thymocytes, Pgp-1⁺c-kit cells, were cultured in the 2-deoxyguartosine treatedfetal thymus. In the presence of both mAbs in the culture, neitherDP nor SP thymocytes developed whereas either of the mAbs partiallyblocked their development. These results indicate that the Cchain is involved in early T cell development as an indispensablesubunlt of the functional IL-7 receptor complex.     

Melanocytes in the nasal cavity and paranasal sinus. Incidence and distribution in Japan

Random, nonselected tissue specimens from 99 Japanese-20 cylindrically cut nasal blocks removed during autopsy (A.C., Autopsy Cases) and 79 cases removed during surgery, consisting of 32 chronic sinusitis cases (C.S.) and 47 nasal polyp cases (N.P.)-were examined histopathologically and electronmicroscopically with respect to distribution and frequency of melanocytes in the nasal cavity and paranasal sinus. Malignant melanoma cases were excluded. The overall incidence of positive cases for melanocytes revealed 21.2% (21 of 99 cases), with an incidence ratio of male to female of 0.9:1.0. Melanocytes were found beginning in the under 19 age group with incidence increasing proportionately with age. Peak incidence was in the 50-year age group at 50%. Melanocytes and melanotic cell foci were distributed in the stroma of the propria mucosa beneath the pseudostratified columnar epithelium and focused around the nasal and paranasal glands and sinuses. In 2 of the 21 cases positive for stromal melanocytes, intraepithelial melanocytes with dendritic processes were found. The histogenesis of malignant melanoma arising from the nasal cavity and paranasal sinus are also discussed in this study.     

A case with multiple myeloma in which serum forms gel precipitation upon exposure to air

We present the case of a 69-years-old man who was admitted to hospital with multiple myeloma. IgG-kappa type monoclonal protein was detected in the serum. When we separated the serum obtained from blood sample of the patient and the lid of the collecting tube was opened, the patient's serum became gelled immediately. When the lid of the collecting tube remained closed, the patient's serum did not become gelled even at 4 degrees C. Moreover, the gelled serum of the patient did not resolve at 56 degrees C. Taken together, these results indicated that gel formation of the patient's serum may not be due to cryoglobulin. It was found that the pH of the patient's serum elevated to pH 8.0 quickly after exposed to air. It was also found that the patient's serum, but not the sera of other IgG-kappa multiple myeloma patients, became gelled as soon as PBS of pH 8.0 was added. These results highly suggest that the patient's serum becomes gelled at pH 8.0. However, the isoelectric focusing of isolated precipitation in the patient showed fractions around the pH 8.5-8.7 zone, which was different from the pH at which the precipitation began to form. We think that this may be the first report of a multiple myeloma patient whose serum becomes gelled after exposed to air.     

Induction of in situ immune complexes in rat glomeruli using avidin, a native cation macromolecule

This reports a perfusion study using avidin, a native cation macromolecule, followed by rat anti-avidin antibody given directly into the rat renal artery. After 10 min perfusion with avidin, an indirect immunofluorescent study revealed a fine granular distribution of rat IgG along the glomerular capillary loops; an electromicroscopic study showed small particles at sites identical to the position of the anionic sites of the glomerular basement membrane (GBM). After 10 min perfusion with anti-avidin antibody following avidin, rat IgG was heavily deposited along the glomerular capillary loops and electron-dense deposits were observed subendothelially. Rats were administered also intravenous avidin followed 1 h later by rat anti-avidin antibody. The staining pattern of rat IgG, initially almost linear, became granular along the glomerular capillary loops by 72 h. Twenty-four hours later small electron dense deposits, initially localized subendothelially, were found in the subepithelial region with swelling of epithelial foot processes. These observations show that avidin binds to the anionic sites of the GBM, acts as a planted antigen, and results in in situ immune-complex formation.     

Colocalization of a carnosine-splitting enzyme,tissue carnosinase (CN2)/cytosolic non-specific dipeptidase 2 (CNDP2), with histidine decarboxylase in the tuberomammillary nucleus of the hypothalamus

Carnosine is a naturally occurring dipeptide (β-alanyl-l-histidine) present in mammalian tissues such as the brain and skeletal muscles. Carnosine is not only a radical scavenger but also a possible neurotransmitter-like molecule that regulates neuronal functions such as hypothalamic control of the autonomic nervous system. CN2 (CNDP2) is a cytosolic enzyme that can hydrolyze carnosine to yield l-histidine and β-alanine. In order to understand the functions of carnosine and CN2 in the brain, we have investigated the immunohistochemical localization of CN2 in the hypothalamus. CN2-immunoreactivity was highly concentrated in neuronal cells in the dorsal part of the tuberomammillary nucleus of the posterior hypothalamus. Since the tuberomammillary nucleus is the exclusive origin of histaminergic neurons, we further investigated whether CN2 is present in the histaminergic neurons. We found that CN2-immunoreactivity was colocalized with that of histidine decarboxylase, which is the key enzyme for histamine biosynthesis specifically expressed in the histaminergic neurons of the tuberomammillary nucleus. These results suggest that CN2 is highly expressed in the histaminergic neurons in the tuberomammillary nucleus, implying that it may supply histidine to histaminergic neurons for histamine synthesis.     

T-cadherin (CDH13, H-cadherin) expression downregulated surfactant protein D in bronchioloalveolar cells

T cadherin is a unique cadherin cell adhesion molecule that is anchored to the surface membrane through a glycosyl phosphatidyl inositol (GPI) moiety. In the present study, we postulated that T cadherin could regulate surfactant protein (SP)-D gene expression in human bronchioloalveolar type-II cells. We transfected A549 cells (human lung cancer cell line with alveolar type-II cell characteristics) with the T-cadherin expression vector. Both original and control plasmid-transfected A549 cells expressed SP-D; however, neither human nor murine T-cadherin-transfected A549 cells expressed SP-D mRNA. The downregulation of SP-D production in human T-cadherin-expressed A549 cells was also demonstrated using Western immunoblotting techniques. Control vector-transfected A549 cells showed a positive band of SP-D but not of T cadherin. In contrast, T-cadherin-transfected A549 cells, which expressed T-cadherin protein, did not produce SP-D. We further examined the relationship of T cadherin and SP-D expression in secondary pulmonary alveolar proteinosis associated with hematolymphoid malignancies. SP-D was detected in bronchioloalveolar type-II cells in alveolar proteinosis. However, little or no T-cadherin expression was detected in alveolar type-II cells in these patients. To our knowledge, this is the first report describing an effect of cadherin on SP production in bronchioloalveolar cells.     

Erythropoietin concentrations are elevated in the peritoneal fluid of women with endometriosis

Erythropoietin (Epo) is an important regulator of erythropoiesis and stimulates the proliferation of early erythroid precursors as well as the differentiation of late erythroid precursors of the erythroid lineage. However, recent studies have indicated that Epo also has angiogenic properties and plays an important role in the oestrogen-dependent cyclical angiogenesis within the mouse uterus. It was therefore postulated that Epo may be an important angiogenic factor in endometriosis. In order to address this hypothesis the concentration of Epo in peritoneal fluid (PF) was determined in patients with or without endometriosis. PF was collected from patients with endometriosis (n = 42) or without endometriosis (n = 18). Detectable concentrations of Epo were found in all PF samples analysed. The concentration of Epo in PF from patients with endometriosis was significantly higher than that in the control group (13.1 +/- 1.2 mIU/ml versus 7.2 +/- 0.7 mIU/ml, mean +/- SE respectively, P < 0.01). Furthermore, in patients with endometriosis the Epo concentrations in PF from patients with stage I disease (n = 17, 16.6 +/- 3.0 mIU/ml) were significantly higher than those with stage II (n = 8, 10.7 +/- 1.2 mIU/ml, P < 0.03), III (n = 13, 8.4 +/- 1.0 mIU/ml, P < 0.01), IV disease (n = 7, 7.5 +/- 1.0 mIU/ml, P < 0.01). These data suggest that Epo may play a role in the pathogenesis of endometriosis particularly in the initiation of the disease.     

Transitional cell carcinoma with sarcomatous elements in the urinary tract. Six cases examined by immunohistochemistry.

We report six cases of carcinoma showing sarcomatous change in the urinary tract examined by conventional histochemistry and immunohistochemistry. All of the cases were transitional cell carcinoma with or without focal squamous cell carcinoma. Sarcomatous components resembling spindle cell sarcoma with a marked myxoid stroma or chondrosarcomatous element were also observed in all cases. The sarcomatous elements were closely associated with the areas of squamous cell carcinoma in three cases. Various histochemical staining procedures demonstrated mesenchymal features in the stroma of sarcomatous areas. By immunohistochemical examination, the epithelial components showed positive reactions for keratin, epithelial membrane antigen and, focally, carcinoembryonic antigen. The sarcomatous components revealed a positive immunoreaction for keratin but lacked other epithelial markers in all cases. Chondrosarcomatous elements in two cases were positive for both keratin and S-100 protein. These findings indicate that sarcomatous elements in carcinoma may represent mesenchymal metaplasia with partial or complete loss of epithelial features. However, further study will be necessary in order to determine whether heterogeneous elements, such as chondrosarcomatous areas, are epithelial or truly mesenchymal in origin.