Experimental lupus nephritis in severe combined immunodeficient (SCID) mice: remodelling of the glomerular lesions by bystander IgM antibodies

MRL/Mp-lpr/lpr (MRL/lpr) mice develop glomerular lesions with regular variations in their histopathological manifestations, similar to those in lupus nephritis. These lesions are mainly either cell-proliferative or wire loop-like and are associated with glomerular deposits of immunoglobulins, most frequently IgG and IgM. We previously established a nephritogenic IgG3-producing hybridoma clone, B1, from an MRL/lpr mouse, which induces only a 'wire loop-like' type of glomerular lesion when injected into SCID mice. Injection of SCID mice with an anti-trinitrophenyl IgM antibody-producing hybridoma clone, Sp6, following injection of the B1 clone, however, resulted in the development of a 'cell-proliferative' type of glomerular lesion, associated with an accumulation of both antibodies in glomeruli. This accumulation occurred even though Sp6 IgM antibodies did not react with B1 IgG3 antibodies and vice versa. A mutant clone of Sp6, T/13microE/3.1, which produces antibodies deficient in C1q binding, produced a similar effect as that of the Sp6 clone, i.e. 'cell-proliferative' lesions. Again the B1 antibodies did not react with T/13microE/3. 1-IgM antibodies and vice versa. We therefore conclude that bystander IgM antibodies contribute to the remodelling of glomerular lesions in situ, following glomerular injury by the nephritogenic antibodies.     

Pathological analysis of hypertrophic cardiomyopathy simulating dilated cardiomyopathy

The pathomorphologic features of hypertrophic cardiomyopathy simulating dilated cardiomyopathy in the late stage (HCM-DCM) were compared with those of ordinary hypertrophic cardiomyopathy (HCM). Seven autopsied hearts with HCM-DCM and 11 with HCM were assessed quantitatively using an image analyzer. Unlike HCM, significant left ventricular enlargement and wall thinning were observed in HCM-DCM, and the percentage areas of massive fibrosis and disarray were significantly greater. In HCM-DCM, the disarray was distributed diffusely, whereas massive fibrosis was distributed more intensively in the ventricular septum and anterior wall than in the lateral and posterior wall. Narrowing of intramyocardial small arteries was observed more frequently in HCM-DCM, especially in the ventricular septum and anterior wall, than in HCM. These results suggest that the enlargement and wall thinning of the left ventricle in HCM-DCM are attributable to non-uniform progression of massive fibrosis, which is closely related to small-arterial lesions.     

Association of DR4 with pemphigus

HLA typing for the A, B, C, and D locus antigens was performed on 65 patients with pemphigus vulgaris and on 558 controls living in the Los Angeles area. The patients were divided into several categories. These included Jewish and non-Jewish patients, patients with only mucous membrane involvement, only skin or both mucous membrane and skin involvement, and those with a single-episode or recurrent disease. Depending on the highest titer of anti-intercellular cement substance antibody titer, the patients were categorized into those whose titers were 0-80, 160-320, and 640 or greater. A statistically increased incidence of HLA-A25, HLA-B38, and HLA-DR4 antigens was observed in patients compared to controls. This incidence was significantly higher in Jewish compared to non-Jewish patients. The correlations were insignificant in the group with an antibody titer of 0-80, but significant in those with a titer of 160-320, and even more significant in those with titers greater than 640. No significant differences were present between patients who had a single-episode or recurrent disease or in those that had only mouth or only skin involvement. In all categories tested, the association was stronger with DR4 than with A26 or B38. DR4 was present equally in B38-positive and B38-negative patients. The primary association of pemphigus vulgaris may be with the DR4 antigen, and it may be a marker for the severity of the disease.     

Tissue distribution of the Pk antigen as determined by a monoclonal antibody

Using an anti-Pk monoclonal antibody (mAb) designated CPK-1, the expression of the Pk antigen was assessed on normal human tissue from non-Pk individuals. Although the Pk antigen was detected on fibroblasts and blood vessels as previously reported, it was also found on smooth muscle cells of the digestive tract and the urogenital system. Pk was also found on glandular cells of the stomach, oesophagus and prostate. Additionally, CPK-1 reacted weakly with oesophagus squamous cells, and a small number of glomeruli and tubules in the kidney. The mechanism of expression of the Pk determinant in non-Pk individuals is discussed.     

Evidence of the monoclonal composition of human endometrial epithelial glands and mosaic pattern of clonal distribution in luminal epithelium

The endometrium is a highly regenerative tissue that plays a crucial role in implantation. We examined the clonal constitution of glandular cells as well as the luminal epithelium of this unique tissue. Using collagenase-based digestion techniques with microscopic manipulation, we isolated individual human endometrial glands and examined their clonality using a polymerase chain reaction-based assay for nonrandom X chromosome inactivation with an X-linked androgen receptor gene. Most of the glands analyzed were composed of monoclonal populations of epithelial cells and one of the glands exhibited a loss of heterogeneity in the androgen receptor gene. In addition, adjacent glands within a 1-mm(2) area shared clonality, suggesting that clonality of the luminal epithelium is regionally defined. The clonality of endometrium was further confirmed in a study of female mice that harbor the green fluorescent protein gene on either the maternal or paternal X chromosome. Fluorescent microscopy of uterine sections revealed that individual endometrial glands consisted completely of either fluorescent or nonfluorescent cells and that the surface epithelium exhibited a clear boundary between these cell types. These findings suggest that single or multiple stem cells with uniform clonality exist on the bottom of each endometrial gland and genetic alterations occurring in such cells may play a critical role in endometrial carcinogenesis. The possible association between area-specific X inactivation of the endometrial surface and the endometrial receptivity of embryo implantation remains to be clarified.     

Mother and daughter with 45,X/46,X,r(X)(p22.3q28) and mental retardation: analysis of the X-inactivation patterns

We report on a mother and daughter both with a 45,X/46,X,r(X)(p22. 3q28) karyotype and mental retardation. Fluorescence in situ hybridization (FISH) and microsatellite analyses for 14 loci/region at Xp22.3 and seven loci/region at Xq28 indicated that the ring X chromosome was missing a roughly 12-Mb region from Xp22.3 with the breakpoint between DXS85 and DXS9972, and another region of less than 100 kb from Xq28 with the breakpoint distal to the region defined by the FISH probe c8.2/1. X-inactivation analysis, using the methylation status of the AR gene (exon 1) as an indicator, showed that the normal and ring X chromosomes in the X,r(X)(p22.3q28) cell lineage were randomly inactivated. The Xp22.3 deleted region partially overlaps with the regional intervals of MRX19, MRX21, MRX24, MRX37, MRX43, and MRX49 associated with heterozygote manifestation. Therefore, it is likely that one or more of these MRX genes, subject to X-inactivation, are lost from the ring X chromosome, and that reduced expression of the MRX gene(s) caused by random X-inactivation has resulted in mental retardation in the mother and daughter.     

Sources of Ca2+ in relation to generation of acetylcholine-induced endothelium-dependent hyperpolarization in rat mesenteric artery

1. The aim of the present study was to identify the sources of Ca²⁺ contributing to acetylcholine (ACh)-induced release of endothelium-derived hyperpolarizing factor (EDHF) from endothelial cells of rat mesenteric artery and to assess the pathway involved. The changes in membrane potentials of smooth muscles by ACh measured with the microelectrode technique were evaluated as a marker for EDHF release.
2. ACh elicited membrane hyperpolarization of smooth muscle cells in an endothelium-dependent manner. The hyperpolarizing response was not affected by treatment with 10 μM indomethacin, 300 μM N^G-nitro-L-arginine or 10 μM oxyhaemoglobin, thereby indicating that the hyperpolarization is not mediated by prostanoids or nitric oxide but is presumably by EDHF.
3. In the presence of extracellular Ca²⁺, 1 μM ACh generated a hyperpolarization composed of the transient and sustained components. By contrast, in Ca²⁺-free medium, ACh produced only transient hyperpolarization.
4. Pretreatment with 100 nM thapsigargin and 3 μM cyclopiazonic acid, endoplasmic reticulum Ca²⁺-ATPase inhibitors, completely abolished ACh-induced hyperpolarization. Pretreatment with 20 mM caffeine also markedly attenuated ACh-induced hyperpolarization. However, the overall pattern and peak amplitude of hyperpolarization were unaffected by pretreatment with 1 μM ryanodine.
5. In the presence of 5 mM Ni²⁺ or 3 mM Mn²⁺, the hyperpolarizing response to ACh was transient, and the sustained component of hyperpolarization was not observed. On the other hand, 1 μM nifedipine had no effect on ACh-induced hyperpolarization.
6. ACh-induced hyperpolarization was nearly completely eliminated by 500 nM U-73122 or 200 μM 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate, inhibitors of phospholipase C, but was unchanged by 500 nM U-73343, an inactive form of U-73122. Pretreatment with 20 nM staurosporine, an inhibitor of protein kinase C, did not modify ACh-induced hyperpolarization.
7. These results indicate that the ACh-induced release of EDHF from endothelial cells of rat mesenteric artery is possibly initiated by Ca²⁺ release from inositol 1,4,5-trisphosphate (IP₃)-sensitive Ca²⁺ pool as a consequence of stimulation of phospholipid hydrolysis due to phospholipase C activation, and maintained by Ca²⁺ influx via a Ni²⁺- and Mn²⁺-sensitive pathway distinct from L-type Ca²⁺ channels. The Ca²⁺-influx mechanism seems to be activated following IP₃-induced depletion of the pool.

     

Metastatic seeding of bile duct carcinoma in the transhepatic catheter tract: Report of a case

We describe herein the case of a 51-year-old woman in whom metastatic tumor seeding of the percutaneous transhepatic biliary drainage tract occurred following a pancreatoduodenectomy for carcinoma of the distal common bile, duct. An abdominal computed tomography scan done 6 months after the initial operation detected a hepatic lesion located at the site of the previous percutaneous transhepatic biliary drainage tract. Implantation of bile duct carcinoma in the drainage tract was diagnosed, and the recurrent tumor was successfully resected by performing a subsegmentectomy of segment 3 and removal of the adjacent abdominal wall. At present, 5 years and 4 months after the second resection, the patient is in good health without any signs of recurrence. This case report demonstrates that an aggressive surgical approach should be performed for tumor seeding of a transhepatic biliary catheter tract.