Isolation of a cDNA for a phosphoenolpyruvate carboxylase from a monocot CAM-plant, Aloe arborescens: structure and its gene expression

A phosphoenolpyruvate carboxylase (PEPCase) cDNA was isolated from Aloe arborescens, a monocot CAM plant. Northern analysis of the PEPCase transcript indicated that it is specifically expressed in green leaves, strongly suggesting its involvement in CAM photosynthesis. No diurnal change in expression level was evident. Western blot analysis also showed no alteration of the amount of the PEPCase protein. These results suggest that circadian rhythm in PEPCase activity may be regulated post-translationally. The representative cDNA clone contained an ORF encoding 964 amino acid residues. Deduced amino acid sequence of the aloe PEPCase is highly conserved as compared with other PEPCases. The phosphorylation site which may be modified by PEPC-kinase was conserved. An evolutional map with known PEPCases suggested that CAM-type PEPCases were located between C4 and housekeeping PEPCases.

Cross-bridge movement in rat slow skeletal muscle as a function of calcium concentration

A single fibre bundle from rat soleus muscle was chemically skinned with saponin and the transfer of myosin heads from the thick filaments to the thin filaments at a sarcomere length of 2.4 microm was measured as a function of Ca2+ concentration using an x-ray diffraction method at 4-7 degrees C. In the relaxed state, the 1,0 spacing was 42.08 nm. The spacing showed no significant decrease when the Ca2+ concentration was below the threshold (-log10 [Ca2+] or pCa 5.8). No significant transfer of the myosin heads occurred when the Ca2+concentration was below the threshold (pCa 5.8). When the muscle was maximally activated at pCa 4.4, the spacing decreased to 40.35 nm. During the maximum isometric contraction at pCa 4.4, 54. 9 +/- 6.5% (+/-SE of the mean) of the myosin heads were transferred to the thin filaments. The transfer of the myosin heads was approximately proportional to relative tension. These results suggest that myosin heads of both fast-twitch and slow-twitch skeletal muscles transferred on the common movement as a function of Ca2+ concentration.

Laparoscopic splenectomy aided by balloon occlusion of the splenic artery: report of a case

Laparoscopic splenectomy often involves difficulties in patients with splenomegaly because of a poor visual field and distorted and enlarged vessels secondary to the enlarged spleen. For safe and efficient laparoscopic splenectomy, we performed balloon occlusion of the splenic artery with the interventional angiographic technique in a patient with hereditary spherocytosis and splenomegaly. This new approach may be useful in terms of safety and time savings, especially in patients with splenomegaly.

The effect of diastolic vibration on the relaxation of rat papillary muscle

OBJECTIVE

It has been demonstrated that the application of an external mechanical vibration during the ventricular relaxation phase of the heart (diastolic vibration) decreases the time needed for myocardial relaxation. The objective of this study is to see whether this vibration-induced decrease in relaxation time is an intrinsic property of the contractile proteins. We hypothesize that this decrease in duration of the late systolic phase by diastolic vibration is likely to be due to a forced detachment of crossbridges from the actin filament. This would then result in a decrease in the relaxation time of myocardial tissue.

METHODS

A controlled vibration of variable amplitude and frequency was applied to isolated twitching rat papillary muscles. Vibration was initiated from directly after peak tension development and ended when tension had returned to baseline. Effects of applied vibration were expressed as changes in the time interval from 90% rising- to 50% falling-force level, which was termed the 'late systolic phase'.

RESULTS

The data showed that in general diastolic vibration decreased the duration of this late systolic phase. A vibration of 1.0% of Lmax at 50 Hz in the late systolic phase shortened this period by 27 ms (20-30%) on average. At increasing amplitude of vibration the increase in the rate of relaxation was even more pronounced. Shortening of this duration was slightly less at frequencies of vibration below 40 Hz than at higher frequencies of vibration. Changes in the resting muscle length did not result in significant changes in shortening of the studied relaxation period.

CONCLUSION

The results show that relaxation is accelerated during application of an external vibration during the period of tension fall of an isolated cardiac muscle preparation. Therefore, we can conclude that the acceleration of relaxation due to vibration is primarily due to properties of the myocytes themselves rather than to the complex geometric structure of the heart. Tension in the relaxation phase was reduced during diastolic vibration, which suggests that the number of crossbridges bound to the actin filament was reduced by the length perturbation.

Cumulative incidence and prevalence of childhood autism in children in Japan

BACKGROUND

An epidemiological survey of childhood autism as defined in ICD-10 Research Criteria was conducted in the northern part of Yokohama, Japan.

METHOD

The routine health checkup for 18-month-old children served as the initial mass-screening, and all facilities which provide child care services function to detect all cases with childhood autism and refer them to the Yokohama Rehabilitation Centre.

RESULTS

Cumulative incidence of childhood autism up to 5 years of age among the birth cohort of 1988, and prevalence on 1 January 1994, among residents born in 1988 were estimated

RESULTS

Cumulative incidence and prevalence were 16.2 per 10,000 and 21.1 per 10,000, respectively. Children with high-functioning autism who had IQs of 70 and over constituted approximately half of all the children with childhood autism. CONCLUSION. It was confirmed through better detection of high-functioning cases that childhood autism in Japan is more common than formerly estimated.

[Fas antigen is expressed in human diseased muscles, but does not link to apoptosis]

In an attempt to determine whether the Fas-Fas-ligand mediated apoptosis occurs in the pathologic process of human myopathies, we examined the expression of Fas antigen, Fas-ligand mRNA, and chromosomal DNA fragmentation in the muscle cells of several human muscle disorders. The Fas antigen of a whole molecule was expressed on the muscle fibers of patients with muscle wasting diseases. However, there was no evidence of an apoptotic process, nor Fas-ligand synthesis in the diseased muscle tissue. Therefore, the expression of Fas antigen on muscle fibers in diseased muscle might be related to unknown biological functions other than "apoptosis" in the process of muscle fiber injury.

Comparison of endothelium-derived relaxing factor activity between nonpregnant and pregnant rats

The tension of isolated ring preparation of aorta from nonpregnant and pregnant rats was measured isometrically to study the effect of pregnancy on endothelium-derived relaxing factor activity. Contraction in response to norepinephrine and potassium chloride was greater in aortae from nonpregnant rats than in those from pregnant rats. The endothelium-dependent relaxation that was caused by acetylcholine (10(-10)-3 x 10(-9) M) in aortae precontracted with norepinephrine was significantly enhanced in aortae from pregnant rats compared with the relaxation in those from nonpregnant rats. NG-nitro-L-arginine methyl ester (L-NAME) inhibited the endothelium-dependent relaxation in both aorta from pregnant and nonpregnant rats. L-Arginine reversed the inhibition of L-NAME. Those results suggest that the enhanced endothelium-derived relaxing factor activity in rats aortae is associated with pregnancy.

Plasma vanillylmandelic acid level as an index of psychological stress response in normal subjects

The relationships between psychological stress responses and plasma levels of vanillylmandelic acid (VMA), 3-methoxy-4-hydroxyphenylglycol (MHPG), homovanillic acid (HVA), and 5-hydroxyindolacetic acid (5-HIAA) were investigated in normal volunteers. Two questionnaires were used to measure stress: the Psychological Stress Response Scale (PSRS) and the State-Trait Anxiety Inventory (STAI). Plasma levels of VMA--but not MHPG, HVA, and 5-HIAA--showed significant positive correlations with PSRS emotional and cognitive-behavioral stress and STAI state anxiety. Significant positive correlations were also found between plasma levels of VMA and MHPG and psychological stress responses measured repeatedly in a longitudinal study of an Olympic swimmer. Plasma VMA measurements, which reflect the level of activity of the peripheral sympathetic nervous system, may provide a useful biochemical index of psychological stress responses in normal subjects.

Cloning and characterization of mouse tec promoter

Tec is a cytoplasmic protein-tyrosine kinase highly expressed in hematopoietic precursor cells. To investigate the mechanism regulating its expression, we cloned and characterized the mouse tec promoter. The promoter region does not contain the authentic TATA or CAAT box but has several consensus binding motifs for GATA and SP1. The nucleotide sequence surrounding the major transcription initiation site determined 5' RACE-PCR appeared to be homologous to the "initiator" consensus sequence which is frequently found in genes lacking TATA and CAAT. The promoter activity of the 5' flanking region was confirmed by using the luciferase assay. The present analysis will provide insights into the mechanism for the expression and regulation of the Tec molecule.

Communicative interaction of myosins along an actin filament in the presence of ATP

Myosin molecules contacting an actin filament in the presence of ATP were found to regulate the filamental fluctuations due to ATP hydrolysis in a communicative manner along the filament. As an evidence of the occurrence of the communication, ATP-activated fluctuating displacements of the filament in the direction perpendicular to its longitudinal axis were identified to propagate at a finite velocity not less than about 0.2 micron/s unidirectionally along the filament.

Prevention of posttransfusion hepatitis by screening with second-generation anti-HCV antibody and clinical features of HCV infection

After adaptation of the second-generation anti-hepatitis C virus (HCV) test, the incidence of post-transfusion hepatitis (PTH) resulted in 5.2% (11/208), which was significantly lower than that 10.5% (22/209) demonstrated by screening donor blood for C100-3 antibody. The 11 cases of PTH, three were classified as definite PTH and the other were as suspected one. Of two cases with definite PTH and two cases with suspected PTH, their blood samples after transfusion became positive for HCV-RNA, and three cases of those showed a second peak of alanine aminotransferase (ALT) more than 4 weeks after operation. On the other hand, of seven cases containing one definite PTH, their blood samples after transfusion became negative for HCV-RNA, and five cases of those showed ALT peaks within 4 weeks after operation, and returned to normal levels of ALT thereafter. Moreover, in cases of definite PTH, the periods of surgery and anesthesia were longer and the volume of bleeding was much more during operation than in cases of suspected PTH, although the differences were not statistically significant. These findings suggested that cases of PTH include those of transient liver disease attributable to surgery as well as those of HCV infection. In 11 cases of PTH, we consider that 2 cases is true PTH, because these are HCV-RNA positive and have second peak more than 4 weeks after operation and 5 cases is questionable by clinical date. Thus new diagnostic criteria should have established.

[Effect of (-)-N-[(S)-hexahydro-l-methyl-2, 6-dioxo-4-pyrimidinylcarbonyl]-L-histidyl-L-prolinamide (TA-0910), a new TRH analog, on plasma levels of TSH and thyroid hormones in rats]

The stimulatory effect of TA-0910 on the secretions of thyroid-stimulating hormone (TSH) and thyroid hormones was investigated in male and female rats. Single intravenous administration of TA-0910 at 8.3 nmol/body acutely elevated the plasma TSH level, with delayed and moderate increases of T3 and T4 in plasma. Similar increments of plasma TSH and thyroid hormones were observed when TRH was injected at the dose of 0.83 nmol/body. Oral administration of TA-0910 at 2.75 mumol/body was equally potent or slightly more potent to secrete TSH than TRH at 0.275 mumol/body. The elevated TSH by TA-0910 decreased to the control level within 2 hr after intravenous injection or within 6 hr after oral administration; on the other hand, the higher levels of the thyroid hormones were retained for up to 4 and 6 hr after intravenous and oral administration, respectively. These findings indicate that TA-0910 and TRH stimulate the secretion of TSH and thyroid hormones by a similar manner and that the TSH-secreting activity of TA-0910 is lower by an order of magnitude compared with that of TRH.

Computed tomographic findings of Bellini duct carcinoma of the kidney

OBJECTIVE

To analyze CT findings of Bellini duct carcinoma, a rare variant of renal cell carcinoma.

MATERIALS AND METHODS

The CT findings of five cases of Bellini duct carcinoma were reviewed and the findings were recorded.

RESULTS

In all cases the affected kidneys maintained the normal outer contours. In four cases the renal masses protruded into the central sinuses. Contrast enhancement was minimal in four cases.

CONCLUSION

Bellini duct carcinoma should be suspected in cases with these CT findings.

Elevated serum levels of manganese superoxide dismutase in polymyositis and dermatomyositis

We studied serum concentrations of manganese superoxide dismutase (Mn SOD) and copper-zinc superoxide dismutase (Cu/Zn SOD) in 22 patients with polymyositis and dermatomyositis (PM/DM), 87 patients with four types of muscular dystrophy, 20 patients with amyotrophic lateral sclerosis, and 15 patients with collagen vascular diseases (CVD). Serum levels of Mn SOD were increased only in the patients with PM/DM and CVD, and the elevation was more prominent in those with PM/DM. Levels of Cu/Zn SOD were slightly elevated in some patients with PM/DM and Duchenne muscular dystrophy. In patients with PM/DM, the change in Mn SOD levels corresponded to disease activity as closely as or more closely than those of creatine kinase. The results indicate that serum Mn SOD may be a useful clinical marker for PM/DM.

Sharp Increase in the Incidence of Mammary Carcinoma in Kagoshima Prefecture, Japan

Between 1986 and 1990, among a female population of about 0.95 million, 1184 women living in Kagoshima Prefecture were diagnosed pathologically as having mammary carcinoma. The number of patients with mammary carcinoma, the crude incidence rate per 100000 women and age-standardized mammary carcinoma incidence rates were 205, 21.29 and 19.42 in 1986, 212, 22.04 and 19.48 in 1987, 238, 24.74 and 21.8 in 1988, 245, 25.47 and 22.33 in 1989 and 284, 29.57 and 25.69 in 1990, respectively. The number of patients with this disease increased annually. The increase in the age-specific incidence rate of this type of cancer between 1986 and 1990 was 1.38-fold in women between 40 and 49 years of age, 1.46-fold in women between 50 and 59, 1.37-fold in the 60-69 age group, 1.48-fold in the 70-79 age group and 1.91-fold in women over 80. In both the urban and rural areas, the incidence increased annually during the course of this study. In 1990, the age-standardized mammary carcinoma incidence rate in urban area was 1.17 times that in rural area.

Dual role of tropomyosin on chemically modified actin filaments from skeletal muscle

Actin filaments copolymerized with both intact and chemically modified actin monomers restored their sliding activity when they were supplemented with tropomyosin extracted from skeletal muscle. In contrast, the ATPase activation of the copolymers was decreased when supplemented with tropomyosin. The results indicate that tropomyosin along with actin monomers may facilitate sliding activity of the entire actin filament but suppress ATPase activation of intact actin monomers themselves. Accordingly, tropomyosin molecules could be viewed as playing a dual role of both mechanical and chemical regulation of actin monomers.

Inflammatory pseudotumors of the spleen: CT and MRI findings

OBJECTIVE

Our goal was to elucidate the CT and MRI findings of inflammatory pseudotumors of the spleen.

METHODS

The CT and MRI findings of three patients with inflammatory pseudotumors of the spleen were reviewed and compared with the pathologic findings.

RESULTS

On the early phase of CT, the masses were hypodense to the normal spleen, and on the delayed phase, they demonstrated delayed enhancement. On T1-weighted MR images, the masses were isointense to the normal spleen, and on T2-weighted images, the masses had heterogeneous low signal intensities. After administration of Gd-DTPA, the masses showed delayed enhancement.

CONCLUSION

Inflammatory pseudotumors of the spleen were characterized by low signal intensity on T2-weighted MR images and delayed enhancement after contrast material administration on CT and MRI. The fibrous stroma may contribute to these unusual findings.

Temporary spontaneous regression of intrahepatic cholangiocarcinoma

A 34-yr-old man with a liver mass was referred to the hospital. The mass showed temporary spontaneous regression during the follow-up, however, subsequent regrowth of the tumor prompted surgical resection. The specimen revealed intrahepatic cholangiocarcinoma with two distinct components which had been clearly demonstrated on serial CT. Spontaneous resolution of a lesion does not necessarily suggest the lesion's benign, self-limiting entity. Intrahepatic cholangiocarcinoma should be included in the tumors that could spontaneously regress.

ATP-dependent fluctuations of single actin filaments in vitro

Single filaments of actin were observed to fluctuate in the direction perpendicular to their longitudinal axes when they hydrolyzed ATP in the presence of myosin. The transversal fluctuations of actin filaments were identified by reading the transversal displacements of the filaments under a fluorescence microscope. The transversal fluctuations in the absence of ATP decreased their intensity as the number of myosin molecules contacting directly with actin filaments increased. In the presence of ATP, on the other hand, the amplitude of the transversal fluctuations increased in proportion to the ATP concentration up to a certain level, while the sliding velocity of the filaments did not increase significantly over the same range of ATP concentration. The present observation suggests that the chemical energy released from ATP along actin filament binding to myosin molecules is first and primarily converted into kinetic energy of fluctuations in the form of the displacement movements of the filaments in the direction perpendicular to their longitudinal axes.

Spontaneous architectural organization of mammalian epidermis from random cell packing

The cells of the stratum corneum in the epidermis of some mammalian species are precisely stacked in columns in a honeycomb fashion. The epidermis constantly loses surface cells, which are replaced by basal cells that have differentiated during migration to the surface. The path of this migration is seen as precisely defined columns of cells that are in compressed Kelvin's tetrakaidecahedral form. We present a computer simulation of this architectural organization based on the assumption that the cells that migrate upward occupy less crowded regions. The simulation not only explained the mechanism by which the architecture is maintained during the process of cell replacement, but also showed that the architecture was spontaneously organized from initial cells supplied at random. Living organisms consist of self-organizing systems at various levels; however, self-organizing systems have been investigated mostly at the molecular level. The present computer simulation clarified the self-organizing system at the cellular level.

Theoretical treatment of striated muscle: Dynamic extension of four-state model

We constructed a muscle model, based on the model first proposed by Gray and Gonda [6,7), that simulates the twitch contraction of striated muscle. Their original model postulated four basic states in the contraction cycle and predicted the properties of steady state contraction in striated muscle. Using the relationship between steady state tension and calcium concentration, we described several rate constants as functions of calcium concentration and calculated the number of attached crossbridges at various calcium concentration values. The results for both skeletal and cardiac muscle were approximately consistent with those of X-ray studies. Assuming that rate constants change immediately with the phasic alteration of intracellular calcium concentration, we estimated the time course of crossbridge distribution during twitch contraction; these findings were also consistent with those of X-ray studies. We also simulated the effects of calcium concentration and sarcomere length on the magnitude of twitch tension. These simulations suggest that the major determinants of crossbridge distribution during twitch contraction are the time courses of calcium transients and the rate constants of crossbridge kinetics. Our findings suggest that the model used in this study provides a theoretical basis for interpreting the characteristics of cardiac muscle encountered in the clinical setting.

Hepatocellular carcinoma with sarcomatous change: characteristic findings of two-phased incremental CT

BACKGROUND

Because of its poor prognosis, the diagnosis of hepatocellular carcinoma with sarcomatous change (HCCSC) is clinically important. The purpose of this study is to elucidate the characteristic CT findings of HCCSC.

METHODS

Two-phased dynamic incremental CT images of six histologically proven HCCSC were retrospectively reviewed.

RESULTS

All tumors (100%) exhibited peripheral enhancement on delayed CT images. Lymphadenopathy was observed in 100% (six of six patients); intrahepatic metastases, in 83% (five of six). Both metastatic lesions showed findings similar to those of the primary hepatic tumors, such as peripheral enhancement. Histopathological delayed and/or prolonged peripherally enhanced areas consisted of viable cancer cells with sarcomatous changes.

CONCLUSIONS

The appearance of HCCSC on CT is that of an irregularly demarcated intrahepatic mass with delayed or prolonged peripheral enhancement, frequently with intrahepatic metastases and lymphadenopathy.

Lymph-node metastases: efficacy for detection with helical CT in patients with gastric cancer

PURPOSE

To determine the efficacy of helical computed tomography (CT) in the detection of lymphadenopathy in patients with gastric cancer.

MATERIALS AND METHODS

Helical CT (5-mm section thickness, 5-mm/sec table incrementation) was performed in 58 patients (39 men, 19 women; mean age, 63.8 years) with gastric cancer; 1,082 lymph nodes (138 positive, 944 negative for metastasis) were resected at surgery. Findings at CT and resection were compared. Sensitivity for detecting lymph nodes was evaluated according to nodal size and presence of metastasis.

RESULTS

Seven (1.1%) of 649 lymph nodes 1-4 mm, 160 (45.1%) of 355 nodes 5-9 mm, and 56 (72%) of 78 nodes larger than 9 mm were detected at CT. For nodes of at least 5 mm, sensitivity for detecting metastasis-positive nodes (79 [75.2%] of 105 nodes) was higher than that for detecting metastasis-negative nodes (137 [41.8%] of 328; P < .01). Differences between positive and negative nodes in CT attenuation (110 HU +/- 25 vs 66 HU +/- 32) and short-to-long axis ratios (0.81 +/- 0.15 vs 0.57 +/- 0.15; P < .001) were significant.

CONCLUSION

Helical CT is effective for detection of metastatic lymphadenopathy from gastric cancer. CT attenuation and lymph-node configuration aid in diagnosis of malignant adenopathy.