Role of protein kinase C in the modulation of multidrug resistance: expression of the atypical gamma isoform of protein kinase C does not confer increased resistance to doxorubicin.

Cross-resistance to anticancer drugs, termed multidrug resistance (MDR), is functionally associated with the expression of a plasma membrane, energy-dependent, drug efflux pump termed P-glycoprotein (PGP), the product of the mdr1 gene. We have shown previously that MCF-7 breast carcinoma cells transfected with the human mdr1 gene (BC-19 cells) exhibit greater MDR when stably transfected with protein kinase C alpha (PKC alpha). We now demonstrate that transfection of BC-19 cells with the gamma isoform of PKC (BC-19/PKC gamma cells), which is not normally present in BC-19 cells, does not confer increased resistance to doxorubicin, despite a 19-fold increase in PKC activity. All of the increased PKC activity is accounted for by PKC gamma and it is rapidly down-regulated by phorbol dibutyrate, within 15 min of treatment. Endogenous PKC alpha and PKC epsilon activities are not affected by phorbol dibutyrate. The cytotoxicity of doxorubicin was similar in BC-19/neo or BC-19/PKC gamma cells after either 2-hr or continuous drug exposure, and co-treatment with phorbol dibutyrate increased resistance to doxorubicin 4-fold in both cell lines. Phosphorylation of PGP was similar in both cell lines and drug accumulation was not affected by overexpression of PKC gamma. These results demonstrate that transfection of PGP-expressing cells with an atypical isoform of PKC does not confer increased MDR, and they suggest that the regulation of PGP is phenotype specific with respect to the isoform of PKC.     

Vasodilator effects of C-type natriuretic peptide on cerebral arterioles in rats

The vasodilator effects of C-type natriuretic peptide (CNP) were investigated in isolated rat cerebral arterioles. CNP caused dose-dependent vasodilation, maximally by 10.0±2.2% at 10⁻⁶ M. The median effective concentration (EC₅₀) was 5.2×10⁻¹⁰ M. In contrast, atrial natriuretic peptide and B-type natriuretic peptide, other members of the natriuretic peptide family, produced little or no vasodilation. Pretreatment with methylene blue (10⁻⁴ M) abolished CNP-induced vasodilation, whereas pretreatment with N^G-monomethyl-

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-arginine or indomethacin did not inhibit vasodilation. Thus, CNP is suggested to cause significant vasodilation in cerebral arterioles via a cyclic guanosine monophosphate-dependent mechanism. © 1997 Elsevier Science B.V. All rights reserved.     

Polyglucosan bodies in the central nervous system of a fox.

Polyglucosan bodies (PGB) in the central nervous system of an old male fox, Vulpes vulpes japonica, without neurological signs were examined by light and electron microscopy, lectin histochemistry and immunohistochemistry. Fox PGB were round, slightly-basophilic and PAS-positive structures. Most of the bodies were situated free in the neuropil. Electron microscopically, fox PGB were composed mainly of branching filaments and electron-dense material. Lectin histochemistry revealed that fox PGB contained mannose and galactose in addition to glucose. Fox PGB were immunoreactive for monoclonal antibodies raised against human polyglucosan. These findings indicate that fox PGB are similar to feline ones.     

The anterior choroidal artery syndrome

We reviewed 12 cases of infarcts in the territory of the anterior choroidal artery (AChA) on CT and/or MRI. In each case vascular occlusion in the region was verified angiographically. Although the extent of the lesion on CT/MR images was variable, all were located on the axial images within an arcuate zone between the striatium anterolaterally and the thalamus posteromedially. The distribution of the lesions on mutiplanar MRI conformed well to the territory of the AChA demonstrated microangiographically. The variability of the extent of the infarcts may be explained by variations in the degree of occlusive changes in the AChA or the development of collateral circulation through anastomoses between the AChA and the posterior communicating and posterior cerebral arteries. The extent of the lesion appeared to be closely related to the degree of neurological deficit.     

C3 Deposition in IgA Nephropathy in Children and Adolescents

The aim of this study was to assess the significance of C3 deposition in IgA nephropathy in children and adolescents. One hundred and two patients aged 5–21 years (57 male and 45 female) were studied. The findings of C3 deposition were classified into 8 groups by immunofluorescent (IF) pattern and intensity as follows: group MC3+ (N = 12): mesangiocapillary pattern and 3+ in intensity; group MC2+ (N = 13): mesangiocapillary and 2+; group MC1 + (N = 4): mesangiocapillary and 1 +; group M3+ (N = 11): mesangial and 3+; group M2+ (N = 24): mesangial and 2+; group M1 + (N=18): mesangial 1 +; group S (N = 12): only segmentally positive; and group N (N = 8): negative. Histological changes were scored semiquantitatively as an activity index (cellular proliferation, necrosis, interstitial cell infiltration, and cellular crescents) and a chronicity index (mesangial sclerosis, segmental and global glomerular sclerosis, fibrous crescents, adhesion and tubulo-interstitial change). IF findings were scored semiquantitatively and laboratory findings were also studied. The following results were obtained: 1) The scores of total activity index in MC groups were higher than in the M, S or N groups, and the greater the degree of C3 deposition, the higher the score; 2) Such result was not evident in the chronicity index; 3) High IF scores of IgG and IgM were found in the MC3+ and MC2+ groups; 4) Hematuria was more severe in MC3+ and MC2+ than in other groups, and proteinuria was more prominent in the MC than other groups. Thus the degree of C3 deposition was parallel with histological activity and urinary findings.     

An experimental study on development of gallstone disease after curative gastrectomy for cancer--postoperative alteration of the composition of canine gallbladder bile after subtotal gastrectomy with truncal vagotomy]

In connection with gallstone (GS) formation after gastrectomy for cancer, we examined alteration of the composition of gallbladder bile after subtotal gastrectomy with truncal vagotomy. Of 11 mongrel dogs with cholecystostomy, 3 underwent B-I and 4 B-II gastrectomy. Four dogs without gastrectomy were served as controls. Bile was collected for 12 months. Bile acids were quantified by GLC. The bile was cultured for bacteriology. TBA did not significantly differ among the three groups of the dogs. In the two gastrectomized groups, CDA (a secondary bile acid) kept a higher level and CA (a primary bile acid) maintained a lower concentration compared with those in the controls. A remarkable increase of non-conjugated bile acids was recognized in both gastrectomized groups. Lithogenicity was low for all of the 3 groups. All but 1 control dog incurred bile infection that persisted long. Black pigment stones containing calcium bilirubinate developed in 1 of the 3 B-I and 2 of the 4 B-II dogs but none in the controls. The bile infection seemed to be involved in the development of GS. As the alteration of bile composition and GS occurred solely in the gastrectomized dogs, subtotal gastrectomy with truncal vagotomy might precipitate the GS formation.     

Acute myocardial injury and repeated angina pectoris-like attacks in a young patient with Churg-Strauss syndrome]

A 23-year-old male with bronchial asthma developed eosinophilia (eosinophils greater than 2,000/mm3) and was observed at our hospital. After using a prescribed indomethacin suppository for fever at home, he experienced an attack of acute chest pain and severe dyspnea. He suffered cardiac arrest while being transferred to the ward. After resuscitation, he was diagnosed as having acute myocardial infarction on the basis of electrocardiographic and ultrasonic cardiographic findings, and marked elevation of serum concentrations of myocardial enzymes. Thereafter, he often complained of precordial pain and abdominal pain. When he was administered an analgesic in another hospital, he developed severe precordial pain, and marked ST elevation was recorded on the electrocardiogram. Coronary angiography revealed no stenosis nor atherosclerotic changes, suggesting that severe spasm of the coronary arteries and direct myocardial injury by eosinophils were the causes of the myocardial infarction-like symptoms and angina pectoris-like attacks. He was diagnosed as having Churg-Strauss syndrome (allergic granulomatous angiitis) on the basis of the clinical findings; skin biopsy and transbronchial lung biopsy findings were consistent with the diagnosis. Following steroid administration, his angina-like attacks and abdominal pain ceased. This patient developed two episodes of acute cardiovascular symptoms upon administration of antipyretic analgesics. This suggests that in cases of Churg-Strauss syndrome with aspirin-induced asthma, physicians must be aware of the cardiovascular complications, and such drugs should be administered with caution.     

Clinical features of patients with mild systemic lupus erythematosus.

Clinical features of 16 patients with mild systemic lupus erythematosus (SLE) were compared with those of 21 control patients with moderate or severe disease. Age at the time of diagnosis of SLE was higher in mild disease group. The incidence of the coexistence of Sj?gren's syndrome (SS) at the time of diagnosis of SLE was higher in patients who later developed mild disease. Anti-Sm antibody and decreased levels of C3, C4, and CH50 occurred less frequently in patients with mild disease. SLE patients with the coexistence of SS at the time of diagnosis of SLE may represent a subset with a benign prognosis.     

Sensitive Detection of p53 Gene Mutations in Esophageal Endoscopic Biopsy Specimens by Cell Sorting Combined with Polymerase Chain Reaction Single-strand Conformation Polymorphism Analysis

For the rapid and sensitive detection of p53 gene mutations in esophageal endoscopic biopsy specimens, we combined cell sorting with the polymerase chain reaction and single-strand conformation polymorphism (PCR-SSCP) analysis. Mutations in exons 5–8 of the p53 gene were investigated by FCR-SSCF analysis using 10³ sorted nuclei obtained from each endoscopic biopsy specimen of 16 patients with esophageal cancer. DNAs extracted from their respective surgical specimens were investigated by a conventional method of PCR-SSCP analysis. Mutations in the biopsy specimens were detected in 6 of the 12 aneuploid tumors but in none of the 4 diploid tumors. After tumor cell enrichment by cell sorting, one mutation in exon 8 became apparent, which could not be detected from the surgical specimen by a conventional method of PCR-SSCP analysis. This method should improve the sensitivity of detecting p53 gene mutations, and provides additional information concerning the DNA ploidy pattern in the tumors.     

Embryonal rhabdomyosarcoma of foot with expansive growth between metatarsals

 The case of a 14-year-old girl with rhabdomyosarcoma of the right foot is reported. Plain radiography showed a large nonspecific soft tissue tumor between the metatarsals with bowing of the metatarsals away from the mass. MR imaging showed a large soft tissue mass involving the metatarsals. The findings were conflicting, because the tumor had an infiltrative soft tissue mass and bowing of the metatarsals more suggestive of slow expansive growth. Bowing of short tubular bones may be a process similar to cortical saucerization, which is typically seen in Ewing’s sarcoma, and it can be one of the findings of high grade neoplasms, such as embryonal rhabdomyosarcoma.