The effect of applied mechanical vibration on two different phases of rat papillary muscle relaxation

Applying external mechanical vibration during the relaxation phase of rat papillary muscle decreases the duration of the first part of the relaxation phase. To elucidate the basic mechanism responsible for this shortening of the relaxation period, we applied a controlled vibration to isolated twitching rat papillary muscles during various phases in the relaxation of a twitch. The first part of the relaxation phase was accelerated when length perturbations were applied in the first part of the relaxation of a twitch, dependent on both amplitude and frequency of the perturbation. When vibrations were applied in the first half of the relaxation, the second phase of relaxation was slightly slower (about 20%), but when no vibrations were applied in the first phase, relaxation could be accelerated by applying vibration in the latter half of the relaxation phase. Thus, in the latter half of relaxation, the acceleration of relaxation depended upon perturbation events earlier during that twitch. This study indicates that vibration-induced acceleration of relaxation is due (at least in part) to an apparent increase in detachment rate of attached cross-bridges from the thin filament without substantial reattachment.

A difference in responsiveness of isolated hepatic artery, aorta, portal vein and vena cava of pig to flavin adenine dinucleotide including liver extract

1. Tension of isolated hepatic artery, aorta, portal vein and vena cava of pigs was measured isometrically to study the mode of action of flavin adenine dinucleotide, including liver extract (FADLE). 2. FADLE showed concentration-dependent relaxation of norepinephrine contraction in the hepatic artery, but FADLE had little influence on the aorta, portal vein and vena cava contracted by norepinephrine (NE). 3. In Ca(2+)-free solution, FADLE-induced relaxation in both the hepatic artery and aorta contracted by NE was significantly reduced, and its reduction was greater in the hepatic artery than in the aorta. Furthermore, extracellular Ca2+ dependence of norepinephrine-induced contraction was much larger in the hepatic artery than in the aorta. 4. Results suggest that FADLE shows regional variations in vasorelaxation through the alteration of Ca2+ movement by the cell, and that this may reflect one of the mechanisms in its ability to increase blood flow in hepatic tissue.

Hypervascular renal transitional cell carcinoma with extension into the renal vein and inferior vena cava

A rare case of transitional cell carcinoma (TCC) with extension into the renal vein and inferior vena cava (IVC) is presented. Computed tomography, magnetic resonance imaging, and angiography successfully delineated tumor thrombus in the right renal vein and IVC. TCC should be included in the differential diagnosis of renal tumors that can cause IVC thrombosis.

Formation of the branching pattern of blood vessels in the wall of the avian yolk sac studied by a computer simulation

The present study was performed to provide data to support the notion previously believed but not proved experimentally or theoretically, that blood vessels are formed by the selection of capillaries in the network. In an attempt to understand the mechanism of formation of blood vessel branching structures, the transformation of a capillary network to a branching system in the wall of quail yolk sac was successively recorded by a series of photographs, and a computer simulation was carried out for the process of in vivo vascularization based on the photographs. The simulation demonstrated that a positive feedback system participated in the formation of a branching structure. That is, vessels which had been much used were enlarged, whereas less used vessels were reduced in their size and finally extinguished. The enlarged vessels became major components of the branching system. As the body of an embryo grew, it was observed that polygonal capillary networks enlarged, which led each polygon of the network to divide into a few finer polygons. Then, some of the capillary vessels were again selected and formed a branching system. This process repeated during the body growth, indicating that the vascular system developed adaptively to the body growth. A region where the growth was fast, received much blood flow and produced finer networks of capillaries. Thus, it was experimentally demonstrated for the first time that capillaries in the network are successively selected by a positive feedback mechanism and form blood vessels.

Toxic shock-like syndrome caused by non-group A beta-hemolytic streptococci

Two patients with rapidly developing shock, multisystem organ failure, and destructive soft-tissue infection caused by groups G and C streptococci are described. Both patients died rapidly despite aggressive treatment. The clinical characteristics cannot be distinguished from those of toxic shock-like syndrome, but Streptococcus pyogenes was not recovered. These strains did not produce any previously identified type of streptococcal pyrogenic exotoxins. These findings suggest that toxic shock-like syndrome can be caused not only by group A but also groups G and C streptococci. The causative strains of toxic shock-like syndrome may have something in common with unknown virulent factors for this syndrome.

[Early HCC and adenomatous hyperplasia: evaluation of arterial and portal blood flow with CTA, CTAP, and pathologic correlation]

In order to analyze the hemodynamic properties of early hepatocellular carcinoma (HCC) and adenomatous hyperplasia (AH), three lesions (two HCCs, one AH) depicted as hypoattenuating at CTA and iso attenuating at CTAP were correlated with the histopathological findings. The number of normal hepatic arteries in the tumor was lower than in the liver. Degeneration and narrowing of the lumens were also seen microscopically. All tumors showed the replacing growth pattern and had similar numbers of the portal tracts in the tumor to the liver. The decreased number of intratumoral normal arteries is suspected to be a characteristic finding of the early stage of HCC.

Characterization of the mouse prostaglandin F receptor gene: a transgenic mouse study of a regulatory region that controls its expression in the stomach and kidney but not in the ovary

BACKGROUND

The actions of prostaglandin F2alpha are mediated by a cell-surface receptor (FP), but little is known about the regulation of FP gene expression. To clarify the mechanisms underlying tissue specific transcription of the mouse FP gene, we isolated and characterized mouse genomic DNA clones encoding FP.

RESULTS

Structural analysis revealed that the mouse FP gene is composed of three exons and two introns, and spans more than 11 kilobases. By primer extension and PCR analyses, the major transcription start site was identified as a cytosine nucleotide, but additional sites of transcription initiation were found in the ovary. There was no apparent difference in the FP gene transcription initiation site between the ovary, kidney and stomach. Sequence analysis of the putative promoter region showed only two potential SP-1 binding sites, but no other typical well-known consensus sequences. We generated transgenic mice with the potential promoter region of the FP gene connected to the lacZ reporter gene. Northern blot analysis showed that the pattern of expression of the transgene corresponded to that of FP expression, except in the ovary. Upon analysis by in situ hybridization, the lacZ gene transcripts were found to be expressed in the fundic glands in the stomach, and the cortical tubules in the kidney, in which endogenous FP transcripts were also expressed. On the contrary, expression of lacZ transcripts was not detected in the corpora lutea, where the highest expression of FP mRNA was observed.

CONCLUSIONS

These studies suggest that a separate control mechanism exists for FP expression in the ovary, distinct from the expression in the stomach and kidney.

Anatomy and clinical importance of cholecystic venous drainage: helical CT observations during injection of contrast medium into the cholecystic artery

OBJECTIVE

The purpose of this study was to use helical CT to elucidate the anatomy and clinical importance of cholecystic venous drainage.

SUBJECTS AND METHODS

We performed helical CT of the upper abdomen during injection of contrast medium through a superselectively catheterized cholecystic artery (cholecystic artery CT) in 28 patients, all of whom were surgical candidates for suspected hepatobiliary abnormality. In nine of these patients, CT during arterial portography (CTAP) was also performed.

RESULTS

Cholecystic venous blood most frequently entered peripheral portal branches of hepatic segment V (27 of 28 patients, 96%) and segment IV (26 of 28, 93%). In order of decreasing frequency, cholecystic venous blood also drained to segments I, VI, VIII, III, and VII. Cholecystic venous blood subsequently drained into the middle hepatic vein (21 of 28, 75%) or right hepatic vein (20 of 28, 71%). In two patients with adenocarcinoma involving the gallbladder associated with multiple liver metastases, cholecystic venous drainage was seen around each metastatic focus. In the nine patients in whom both cholecystic artery CT and CTAP were performed, nontumorous portal perfusion defects were attributable to cholecystic venous drainage.

CONCLUSION

Recognition of cholecystic venous drainage as a possible pathway for spread of disease from the gallbladder to the liver and also as one of the causes of non-tumorous portal perfusion defects seen on CTAP is important.

Regulation of interneuron function in the C. elegans thermoregulatory pathway by the ttx-3 LIM homeobox gene

Neural pathways, which couple temperature-sensing neurons to motor and autonomic outputs, allow animals to navigate away from and adjust metabolism rates in response to the temperature extremes often encountered. ttx-3 is required for the specification of the AIY interneuron in the C. elegans neural pathway that mediates thermoregulation. ttx-3 null mutant animals exhibit the same thermotactic behavioral defect as that seen with laser ablation of AIY in wild type, suggesting that AIY does not signal in this mutant. ttx-3 encodes a LIM homeodomain protein. A ttx-3-GFP fusion gene is expressed specifically in the adult AIY interneuron pair, which connects to thermosensory neurons. In ttx-3 mutant animals, the AIY interneuron is generated but exhibits patterns of abnormal axonal outgrowth. Thus, the TTX-3 LIM homeodomain protein is likely to regulate the expression of target genes required late in AIY differentiation for the function of this interneuron in the thermoregulatory pathway. The ttx-3-dependent thermosensory pathway also couples to the temperature-modulated dauer neuroendocrine signaling pathway, showing that ttx-3 specifies AIY thermosensory information processing of both motor and autonomic outputs.

Inhibitory effect of a new steroidal saponin, OSW-1, on ovarian functions in rats

1. This study was undertaken to determine the effects of OSW-1 (3 beta, 16 beta, 17 alpha-trihydroxycholest-5-en-22-one 16-O-(2-O-4-methoxybenzoyl-beta-D-xylopyranosyl)- (1-->3)-(2-O-acetyl-alpha-L-arabinopyranoside)) on the pituitary-ovarian system and the functions of aortic smooth muscle. 2. A single s.c. injection of OSW-1 (9 micrograms kg-1) on the morning of pro-oestrus inhibited the occurrence of the expected next pro-oestrus, whereas administration of OSW-1 at a dose of 4.5 micrograms kg-1 did not affect the oestrous cycle. OSW-1 treatment on the day of dioestrus-1 did not affect the oestrous cycle. 3. At doses of 4.5 and 9 micrograms kg-1 OSW-1, the serum oestradiol (E2) levels at the expected next pro-oestrus were significantly lower than in control (pro-oestrus). The serum luteinizing hormone (LH) levels 4 days after 9 micrograms kg-1 OSW-1 treatment were also markedly lower than those of control. OSW-1 (4.5 micrograms kg-1) did not affect the levels of inhibin, progesterone and gonadotrophins on the same day. 4. OSW-1 did not inhibit the preovulatory LH surge which occurs on the afternoon of pro-oestrus day. 5. The expression of mRNA coding for the cholesterol side chain cleavage cytochrome P-450 (p450scc), an ovarian steroidal limiting enzyme, was suppressed at 24 and 96 h after OSW-1 treatment. 6. Administration of OSW-1 (9 micrograms kg-1) tended to reduce the relaxation of isolated thoracic aorta ring preparations induced by acetylcholine, while there was no difference in the relaxation induced by sodium nitroprusside. 7. Our results show that OSW-1 inhibits ovarian E2 secretion and that the decrease in E2 secretion may contribute to its effects on the oestrous cycle and the sensitivity of the thoracic aorta to relaxation. The decrease in the levels of ovarian steroids induced by OSW-1 may be due to its direct inhibitory action on the gene expression of the steroidal enzyme and on the proliferation of granulosa cells in the ovary.

Requirements for localization of p130cas to focal adhesions

p130cas (Cas) is an adapter protein that has an SH3 domain followed by multiple SH2 binding motifs in the substrate domain. It also contains a tyrosine residue and a proline-rich sequence near the C terminus, which are the binding sites for the SH2 and SH3 domains of Src kinase, respectively. Cas was originally identified as a major tyrosine-phosphorylated protein in v-Crk- and v-Src-transformed cells. Subsequently, Cas was shown to be inducibly tyrosine phosphorylated upon integrin stimulation; it is therefore regarded as one of the focal adhesion proteins. Using an immunofluorescence study, we examined the subcellular localization of Cas and determined the regions required for its localization to focal adhesions. In nontransformed cells, Cas was localized predominantly to the cytoplasm and partially to focal adhesions. However, in 527F-c-Src-transformed cells, Cas was localized mainly to podosomes, where the focal adhesion proteins are assembled. The localization of Cas to focal adhesions was also observed in cells expressing the kinase-negative 527F/295M-c-Src. A series of analyses with deletion mutants expressed in various cells revealed that the SH3 domain of Cas is necessary for its localization to focal adhesions in nontransformed cells while both the SH3 domain and the C-terminal Src binding domain of Cas are required in 527F-c-Src-transformed cells and fibronectin-stimulated cells. In addition, the localization of Cas to focal adhesions was abolished in Src-negative cells. These results demonstrate that the SH3 domain of Cas and the association of Cas with Src kinase play a pivotal role in the localization of Cas to focal adhesions.

Dynamic MRI of the gallbladder lesions: differentiation of benign from malignant

Forty-nine pathologically proven gallbladder lesions were evaluated in 45 patients using dynamic MRI with a spoiled gradient pulse sequence (SPGR), to access the ability of this technique to differentiate benign from malignant gallbladder lesions. The studies were reviewed retrospectively. Signal intensity of the lesions were measured. Twenty-one malignant and 28 benign lesions were classified into three categories: polypoid, diffuse wall thickening, and exophytic. Early and delayed enhancement patterns were evaluated. For the polypoid masses, malignant lesions (n = 9) demonstrated early and prolonged enhancements, whereas benign lesions (n = 14) had early enhancement with subsequent washout (P < .05). For diffuse gallbladder wall thickening, malignant lesions (n = 6) demonstrated early and prolonged enhancement and benign lesions (n = 14) showed relatively slow, prolonged enhancement (P < .05). The exophytic masses (n = 6) all were malignant and demonstrated early and prolonged enhancement. Dynamic MRI can help differentiate benign from malignant gallbladder lesions.

Intracellular hyperthermia for cancer using magnetite cationic liposomes: ex vivo study

Heating properties of magnetite cationic liposomes (MCL) were investigated in ex vivo experiments using implanted cell pellets. The cell pellets, which consisted of rat glioma T9 cells into which MCL had been incorporated in a petri dish, were implanted subcutaneously in the left femoral region of female F344 rats. The rats were placed in a magnetic field generating coil and irradiated with an alternating magnetic field (384 Oe, 118 kHz) for 60 min. The cell pellets were heated to over 43 degrees C by MCL in the magnetic field, but other body parts of the rats were not heated. After 3 cycles of magnetic heating, all glioma cells were killed and no tumor take was observed.

Comparison of helical CT and MR imaging in detecting and staging small pancreatic adenocarcinoma

BACKGROUND

To compare the value of helical computed tomography (CT) and various pulse sequences of magnetic resonance (MR) imaging in the detection and staging of small pancreatic adenocarcinoma.

METHODS

Small pancreatic adenocarcinomas (< or = 2 cm in diameter) in eight patients were evaluated with both helical CT and MR imaging. Five MR imaging pulse sequences that included fat-suppressed T1-weighted images and dynamic study using fast multiplanar spoiled gradient-recalled technique were compared for the tumor detectability. To evaluate the tumor vascularity, angiographic findings were also investigated.

RESULTS

Helical CT delineated the tumor in five cases, and MR imaging depicted the tumor in seven cases. MR imaging could detect the tumor of 0.8 cm in diameter clearly. Although helical CT and dynamic MR imaging missed the tumor of 2 cm with relative hypervascularity, fat-suppressed T1-weighted MR imaging demonstrated it precisely. As for the tumor staging, MR imaging was equal or slightly superior to helical CT.

CONCLUSION

MR imaging is the first modality of choice to evaluate small pancreatic adenocarcinoma, and fat-suppressed T1-weighted images and dynamic study must be performed.

Most probable numbers of enterotoxigenic Clostridium perfringens in intestinal contents of domestic livestock detected by nested PCR

The incidence and numbers of enterotoxigenic Clostridium perfringens in the intestinal contents of cattle, swine and broiler chickens were determined and compared with those of total (enterotoxigenic and nonenterotoxigenic) C. perfringens. The method used for the enumeration of enterotoxigenic C. perfringens consisted of a combination of the most probable number (MPN) method and a nested polymerase chain reaction after enrichment culture of the sample. Enterotoxigenic C. perfringens was found in 26% (4.0 x 10-4.3 x 10(2) MPN/100 g), 22% (4.0 x 10-2.3 x 10(3) MPN/100 g) and 40% (4.0 x 10-2.4 x 10(4) MPN/100 g) of intestinal contents of 50 head each of cattle, swine and broiler chickens, respectively. Whereas, total C. perfringens was found in 76% (9.0 x 10-7.5 x 10(6) MPN/100 g), 44% (7.0 x 10-4.3 x 10(6) MPN/100 g) and 80% (4.3 x 10(2)-9.3 x 10(7) MPN/100 g) of intestinal contents of 50 head each of cattle, swine and broiler chickens, respectively, by the conventional MPN method. In all cases, enterotoxigenic cells were not dominant in the population of C. perfringens: a small number of enterotoxigenic cells of C. perfringens co-existed with a large number of nonenterotoxigenic cells in the same sample. The ratios of enterotoxigenic C. perfringens cells to total C. perfringens cells were 1/10-1/10(5).

The phosphatidylinositol 3' kinase pathway is required for the survival signal of leukocyte tyrosine kinase

Leukocyte tyrosine kinase (LTK) is a receptor tyrosine kinase which belongs to the insulin receptor superfamily and is mainly expressed in pre-B lymphocytes and neuronal tissues. Recently, we demonstrated that LTK utilizes Shc and IRS-1 as two major substrates and while both equally activate the Ras pathway, only IRS-1 suppresses apoptosis of hematopoietic cells, suggesting the existence of another unidentified signaling pathway downstream of IRS-1, which is relevant to the anti-apoptotic activity. In the present study, we found that wortmannin, a specific inhibitor of phosphatidylinositol 3' (PI3)-kinase, abolished the survival effects of LTK. Although c-Cbl is found to be phosphorylated by LTK and therefore is a second candidate linking LTK with the PI3-kinase pathway along with IRS-1, we found that the p85 subunit of PI3 kinase directly binds to tyrosine 753 of LTK, which is located within a YXXM motif, a consensus binding amino acid sequence for the SH2 domain of p85, but fails to bind to IRS-1 or c-Cbl. Ba/F3 cells which stably express the EGF receptor-LTK chimeric receptor carrying a mutation at tyrosine 753 fell into apoptotic death even in the presence of EGF, indicating that the PI3 kinase pathway is required for the survival effects of LTK.

Behavioral and P3 amplitude enhancement in schizophrenia following feedback training

In order to clarify the remediability of behavioral and electrophysiological abnormalities in schizophrenia, hit rate, reaction time, and P3 amplitude from auditory event-related potentials were evaluated before and after feedback training of a task in 14 schizophrenics and 12 age-matched normal controls. Although mean changes in the three indices due to the training were nonsignificant in both schizophrenic and normal control groups as a whole, the changes in hit rate and reaction time correlated significantly with the P3 amplitude change in the schizophrenic (r = 0.60 and -0.58, respectively) but not in the normal control group. The P3 amplitude change also correlated with the P3 amplitude before the training only in the schizophrenic group (r = -0.68), suggesting that the training was more effective for the schizophrenic patients with marked P3 amplitude reduction. The observed P3 amplitude increase due to training may represent an electrophysiological correlate of a remediable aspect of behavioral deficits in schizophrenics, which may underlie the effectiveness of nonpharmacological treatments.

Expression of Fas antigen is not associated with apoptosis in human myopathies

To determine whether the Fas-Fas-ligand mediated apoptosis occurs in the pathologic process of human muscle diseases, we examined the expression of Fas antigen, Fas-ligand messenger RNA, and chromosomal DNA fragmentation in the muscle cells of patients with a variety of human muscle disorders. The present study demonstrated that the Fas antigen of a whole molecule was expressed on the muscle fibers of patients with muscle wasting diseases. However, the apoptotic process did not occur in the muscle cells, and there was no evidence of Fas-ligand synthesis in the diseased muscle tissue. Our data suggest that the expression of Fas antigen on fibers in diseased muscle is related to unknown biological functions other than "apoptosis" in the process of muscle fiber injury.

A phenotypically normal liveborn male after prenatal diagnosis of trisomy 20 mosaicism

We report on a case of prenatally diagnosed trisomy 20 mosaicism. Conventional cytogenetic analysis and fluorescence in situ hybridization (FISH) using a chromosome 20 specific probe were performed on the lymphocytes and extra-embryonic tissues after birth. All of them revealed normal karyotypes. The baby is developing normally at the age of 2 years.

Branch geometry in Cornus kousa (Cornaceae): computer simulations

Computer simulations similar to actual trees were constructed using simple branching rules. Branch orientation with respect to the direction of gravity was a fundamental consideration. In Cornus kousa BUERG. ex HANCE, several types of branches develop from winter buds, varying from orthotropic shoots to plagiotropic ones. Based on actual observations and measurements of branching structures with a wide range of orientations, we made a flexible geometrical model consisting of five forking branches that varied in outgrowth depending on the direction of the shoot with respect to gravity. Repetition of the branching by computer generated a realistic tree pattern, which was close to the shape of a young C. kousa tree. Reproductive shoots seem to be under a branching rule that was a modification of vegetative branching, although the reproductive branch size was considerably smaller than the vegetative one, and reproductive branching was bifurcated instead of five-forked. We conclude that all branchings in orthotropic and plagiotropic shoots in the vegetative phase and shoots in the reproductive phase are formed under the same branching rule, but each has different parameter values.

Identification of PU.1 and Sp1 as essential transcriptional factors for the promoter activity of mouse tec gene

Tec is a cytoplasmic protein-tyrosine kinase abundantly expressed in hematopoietic precursor cells. To investigate the mechanism regulating the expression of Tec molecule, we cloned and analysed 5' flanking region of mouse tec gene up to -2kb from the transcriptional initiation site. Luciferase assays using successive deletion mutants demonstrated that regions from -364 to -323 and from -122 to -63, which contain the consensus binding sequences for PU.1 (GGAA) and Sp1 (GGGCGG), respectively, are important for the transcriptional activity. Gel-shift and supershift assays revealed that PU.1 and Sp1 bind to the these regions through their consensus binding motifs. In addition, introduction of mutations into these motifs resulted in marked decrease in the promoter activity. These results indicate that PU.1 and Sp1 are essential for the transcriptional activity of the tec promoter and suggest that the cooperation of PU.1 and Sp1 plays a substantial role in the preferential expression of the Tec molecule in the hematopoietic lineages.

Acetylcholine-induced relaxation of rat aorta is greatest during estrus in the sexual cycle

Acetylcholine (ACh)-induced relaxation in the aortae precontracted with norepinephrine was significantly enhanced in the aortae from estrus (E) rats, compared with that in those from metestrus (D-1), diestrus (D-2) and proestrus (PE) rats. NG-Nitro-L-arginine methyl ester (L-NAME) inhibited the endothelium-dependent relaxation in E rats. These results suggest that there is a difference in ACh-induced relaxation of the thoracic aorta during the sexual cycle of rats, and the relaxation is greatest in E of the sexual cycle; this may be due to a difference in nitric oxide synthesis in the endothelium in the sexual cycle.

Treatment of hepatic encephalopathy by retrograde transcaval coil embolization of an ileal vein-to-right gonadal vein portosystemic shunt

A 43-year-old non-cirrhotic woman suffered from encephalopathy caused by an extrahepatic portosystemic shunt between the ileal vein and inferior vena cava via the right gonadal vein. Percutaneous transcatheter embolization with stainless steel coils was performed by the retrograde systemic venous approach. Encephalopathy improved dramatically.