Ipsilateral atrophy in children with hemispheric cerebral tumors: CT findings

The CT findings of 19 children under 16 years of age with primary brain tumors in the cerebral hemisphere were investigated with special reference to the existence of cerebral hemiatrophy ipsilateral to the side of the tumor. "Ipsilateral cerebral hemiatrophy" was observed in four of 19 cases (21%). These included two cases with germinoma in the basal ganglia and two with low-grade astrocytoma in the frontal and occipital cortex. This peculiar CT finding was not specific to the location or histology of the tumor. The four cases were characterized by slow progression, which contrasted with the rapid progression of tumors shown in seven cases with a mass effect on CT.     

Sonographic diagnosis of breast carcinoma by a 7.5 MHz high-resolution electronic linear array transducer

The diagnostic quality with 7.5 MHz real-time, transducer was evaluated in 175 cases of breast lesions including 106 carcinoma. All cases were histologically confirmed by surgery or excisional biopsy. In the prospective study, accuracy in carcinoma was 84.6% with true positive ratio of 86.8%. There were 14 false negative cases with carcinoma and 13 false positive cases. Five "early" breast carcinoma within 1 cm in diameter were misdiagnosed as benign breast lesions. The false positive cases were composed of 7 degenerated fibroadenomas, 2 mastopathies and 4 inflammatory changes. In the retrospective study, accuracy in carcinoma was 83.4% with true positive ratio of 93.4%. Compared with the prospective study, false negative cases decreased and false positive cases increased in retrospect. The predictive value of positive results with carcinoma were about 80% in each malignant findings on the criterion of breast carcinoma. The 7.5 MHz electronic, linear-array transducer has several advantages over the 7.5 MHz polymer transducer in detection and also precise observation of the breast lesions.     

Functional linkage of the cardiac ATP-sensitive K+ channel to the actin cytoskeleton

The role of the cytoskeleton in the rundown and reactivation of adenosine triphosphate (ATP) sensitive K⁺ channels (KATP channels) was examined by perturbing selectively the intracellular surface of inside-out membrane patches excised from guinea-pig ventricular myocytes. Actin filament-depolymerizing agents (cytochalasins and desoxyribonuclease I) accelerated channel rundown, while actin filament stabilizer (phalloidin) or phosphatidylinositol biphosphate (PIP₂; inhibitor of F-actin-severing proteins) inhibited spontaneous and/or Ca²⁺-induced rundown. When rundown was induced by cytochalasin D or by long exposure to high Ca²⁺, channel activity could not be restored by exposure to MgATP, but application of F-actin with MgATP could reinstitute channel activity. The processes of rundown and reactivation of cardiac K_ATP channels may thus be influenced by the assembly and disassembly of the actin cytoskeletal network, which provides a novel regulatory mechanism of this channel.     

Rhythmical contractions in pulmonary arteries of monocrotaline-induced pulmonary hypertensive rats

Rhythmical contractions accompanied by an increase in cytosolic Ca2+ concentrations were produced in ring preparations of endothelium-denuded pulmonary arteries from monocrotaline-treated rats, but not in those from vehicle-treated rats, 2-3 h after a resting tension of 15 mN (150-180% of the initial wall length of the artery) was applied. The rhythmical contractions were abolished by nicardipine and ryanodine. Cyclopiazonic acid reduced the relaxation phase of the rhythmical contractions, finally leading to a sustained contraction. Similarly, apamin caused a sustained contraction, whereas charybdotoxin increased the amplitude of the rhythmical contractions. Glibenclamide had no apparent effects on them. Indomethacin and the prostaglandin H2/thromboxane A2 receptor antagonist SQ29548 abolished the rhythmical contractions and reduced the tension, but the thromboxane synthase inhibitor ozagrel had no effect. These results suggest that optimal stretch induces rhythmical contractions in the pulmonary arteries of monocrotaline-induced pulmonary hypertensive rats, to which both Ca2+ influx through voltage-operated Ca2+ channels and Ca2+ release from the endoplasmic reticulum seem to contribute. It is also suggested that small-conductance Ca(2+)-activated K+ channels participate in the relaxation phase of rhythmical contractions. Furthermore, prostaglandin H2 released from nonendothelial cells is likely to play a pivotal role in the induction of rhythmical contractions.     

Protodioscin isolated from fenugreek (Trigonella foenumgraecum L.) induces cell death and morphological change indicative of apoptosis in leukemic cell line H-60, but not in gastric cancer cell line KATO III

Protodioscin (PD) was purified from fenugreek (Trigonella foenumgraecum L.) and identified by Mass, and 1H- and 13C-NMR. The effects of PD on cell viability in human leukemia HL-60 and human stomach cancer KATO III cells were investigated. PD displayed strong growth inhibitory effect against HL-60 cells, but weak growth inhibitory effect on KATO III cells. Morphological change showing apoptotic bodies was observed in the HL-60 cells treated with PD, but not in KATO III cells treated with PD. Flow cytometric analysis showed that the hypodiploid nuclei of HL-60 cells were increased to 75.2, 96.3, and 100% after a 3-day treatment with 2.5, 5, and 10 microM PD, respectively. The fragmentation by PD of DNA to oligonucleosomal-sized fragments, that is a characteristic of apoptosis, was observed to be both concentration- and time-dependent in the HL-60 cells. These findings suggest that growth inhibition by PD of HL-60 cells results from the induction of apoptosis by this compound in HL-60 cells.     

Morphometric difference in the human maxillary nerve fibers between dentulous and edentulous jaw subjects

This study was conducted to quantify the change in the number and size of myelinated nerve fibers of the maxillary nerve with tooth loss in humans. We carried out a morphometric analysis to compare the number and size of myelinated nerve fibers in the human maxillary nerve between four dentulous and four edentulous jaw cases. Our results indicated that the number of axons decreased by approximately 13,000 with tooth loss. The average size of axons remained unchanged, but there was a change in the fiber size distribution, namely the loss of a large number of small-sized axons was accompanied by the total disappearance of small number of large-sized axons.     

A differential assay of NK-cell-mediated cytotoxicity in K562 cells revealing three sequential membrane impairment steps using three-color flow-cytometry

Annexin V and propidium iodide (PI) staining is a general technique for detecting apoptosis by flow-cytometry (FCM). The release of 2',7'-bis-(2-carboxyethyl)-5- (and-6)-carboxyfluorescein (BCECF), a non-lipophilic membrane-impermeable labeling dye, from the cytoplasm of target cells is an indicator of increased membrane permeability. This study aimed to devise a three-color FCM technique involving the BCECF-release parameter in addition to conventional Annexin V and PI staining for the analysis of target K562 cells undergoing cytotoxic/apoptotic processes mediated by natural killer (NK) cells. The results demonstrated the following step-wise process of membrane impairment: (1) initiation of Annexin V staining accompanied by increasing forward scatter (FSC) before BCECF-release, indicating membrane impairment without permeabilization by necrosis; (2) BCECF-release with decreasing FSC before PI influx; and (3) PI staining with the lowest FSC state. Therefore, the early stage of cytotoxicity/apoptosis conventionally defined by the flow-cytometric criteria of Annexin V staining before PI staining could be sub-divided into two stages before and after BCECF-release. Annexin-V staining in tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis was also initiated without BCECF-release. Although the underlying mechanism of the transition process from stage 1 to stage 2 is still unknown, this FCM technique should be a useful tool for differential assays of target cells regarding the sequential processes of NK-induced cytotoxicity.     

Regulation by Ca2+-calmodulin of the actin-bundling activity ofPhysarum 210-kDa protein

Summary From the plasmodia of a lower eukaryote,Physarum polycephalum, we have previously purified a 210-kDa protein that showed similar properties to those of smooth muscle caldesmon. Further characterization of the 210-kDa protein revealed that it bundled actin filaments. This bundling activity was inhibited by calmodulin in the presence of Ca²⁺. Unlike smooth muscle caldesmon, the 210-kDa protein bundled actin filaments whether or not a reducing agent, such as dithiothreitol, was present. The protein was shown to have two (or more) different actin-binding sites which were classified into salt-sensitive and salt-insensitive sites. Electron microscopy revealed that the 210-kDa protein was an elongated molecule (mean length, 97 ± 25 nm) which was bent in the middle. The Stokes radius and sedimentation coefficient of the 210-kDa protein were 130 Å and 2.9 S, respectively. An immunofluorescence study revealed that the 210-kDa protein colocalized with the bundles of actin filaments in thin-spread preparations ofPhysarum plasmodia, suggesting that the 210-kDa protein was regulating the appearance and disappearance of the actin bundles that are associated with the contraction-relaxation cycle of the plasmodia.