Ampicillin concentrations in radicular cysts following a single oral administration of bacampicillin

1. Ampicillin concentrations in cyst wall (wall) and cyst fluid (fluid) of radicular cyst and serum following a single oral administration of bacampicillin (equivalent to 500 mg of ampicillin) were measured by a paper disk method. 2. The mean peak concentrations of ampicillin in wall, fluid, and serum occurred at identical times, 1.5 hr, and were 2.39 micrograms/g, 0.77, and 10.24 micrograms/ml, respectively. 3. Mean ampicillin concentration ratios of wall/serum, fluid/serum, and fluid/wall at the peak time were 0.23, 0.07, and 0.40, respectively. 4. Mean ampicillin concentrations in wall and fluid at the peak time exceeded MIC (minimum inhibitory concentration) for 90% (0.5 microgram/ml) for clinically isolated strains of alpha-hemolytic Streptococci.

Myelo-monocytoid immunophenotypes of B-cell chronic lymphocytic leukemia cells

Leukemia cells from ten patients with B-cell chronic lymphocytic leukemia (B-CLL) and one with B-CLL of mixed cell type (B-CLL/PL) were analyzed to delineate the cellular characteristics, especially the myelomonocytic nature. Most of the surface phenotypes were consistent with the previous reports. However, the frequency of positivity for CD22 and CD25 was much higher in the examined cases of B-CLL than in Western reports. B-CLL cells frequently possessed antigens which are mainly expressed in myelomonocytic cells: 8/10 for CD11b and 4/10 for CD11c, although the presence of CD14 was not apparent (0/10). In addition, colony stimulating factor-1 receptors (CSF-1R) were expressed in 6 of the 10 B-CLL cases. The reactivity with antigens such as CD14, CD11c, and CSF-R was markedly enhanced by in vitro incubation. Alterations in antigen expression and in in vitro survival by growth factors for myelomonocytic lineage were observed in certain cases. These data imply that not only are B-CLL cells phenotypically closely related to myelomonocytic lineage but that they may also be influenced by growth factors for that lineage.

Mixed haplotype A beta Z/A alpha d class II molecule in (NZB x NZW)F1 mice detected by T cell clones

We have tried to demonstrate the existence of a mixed haplotype MHC class II molecule in (NZB x NZW)F1 (B/WF1) mice. When a large panel of keyhole limpet hemocyanin-specific T cell clones derived from B/WF1 mice was analyzed, several clones were shown to be restricted by a F1-specific A beta Z/A alpha d class II molecule. Autoreactive A beta Z/A alpha d-specific T cell clones were also obtained. The ability of the association and expression of A beta Z with A alpha d was confirmed by hybridoma and transfection experiments. Hybridoma cell lines created by fusion of NZW (H-2z) spleen cells with M12.C3 (a A beta d- variant cell line derived from M12.4.1 (H-2d) B lymphoma) cells expressed A beta Z determinants. Transfection of A beta Z genomic DNA to M12.C3 cells resulted in the expression of A beta Z determinants. These hybridoma cell lines and transfectants were able to stimulate A beta Z/A alpha d-specific T cell clones, suggesting the expression of A beta Z/A alpha d molecules on the cell surface. However, attempts to demonstrate the existence of mixed haplotype MHC class II molecules in B/WF1 mice by two-dimensional (nonequilibrium pH gradient gel electrophoresis/SDS-PAGE) gel electrophoresis analysis with the use of anti-class II mAb failed to demonstrate the existence of mixed haplotype A beta Z/A alpha d or A beta d/A alpha z class II molecules in B/WF1 mice. Analysis of mixture of TA beta Z cell and B/WF1 spleen cell lysates immunoprecipitated by anti-A beta Z mAb suggested that the amount of haplotype mixed A beta Z/A alpha d molecules in B/WF1 spleen cells is less than 1/10 that of haplotype matched A beta/A alpha pairs. Our results suggest that, although undetectable by biochemical analysis, small amounts of mixed haplotype A beta Z/A alpha d molecules exist in B/WF1 spleen cells. Also, T cell clones which recognize them exists in B/WF1 mice. Because autoimmune symptoms of B/WF1 mice are shown to be related to heterozygosity at the H-2 region, autoreactive T cell clones which recognize the mixed haplotype A beta Z/A alpha d class II molecule might be involved for the induction of autoimmunity in B/WF1 mice.

Mixed haplotype A beta Z/A alpha d class II molecule in (NZB x NZW)F1 mice detected by T cell clones

We have tried to demonstrate the existence of a mixed haplotype MHC class II molecule in (NZB x NZW)F1 (B/WF1) mice. When a large panel of keyhole limpet hemocyanin-specific T cell clones derived from B/WF1 mice was analyzed, several clones were shown to be restricted by a F1-specific A beta Z/A alpha d class II molecule. Autoreactive A beta Z/A alpha d-specific T cell clones were also obtained. The ability of the association and expression of A beta Z with A alpha d was confirmed by hybridoma and transfection experiments. Hybridoma cell lines created by fusion of NZW (H-2z) spleen cells with M12.C3 (a A beta d- variant cell line derived from M12.4.1 (H-2d) B lymphoma) cells expressed A beta Z determinants. Transfection of A beta Z genomic DNA to M12.C3 cells resulted in the expression of A beta Z determinants. These hybridoma cell lines and transfectants were able to stimulate A beta Z/A alpha d-specific T cell clones, suggesting the expression of A beta Z/A alpha d molecules on the cell surface. However, attempts to demonstrate the existence of mixed haplotype MHC class II molecules in B/WF1 mice by two-dimensional (nonequilibrium pH gradient gel electrophoresis/SDS-PAGE) gel electrophoresis analysis with the use of anti-class II mAb failed to demonstrate the existence of mixed haplotype A beta Z/A alpha d or A beta d/A alpha z class II molecules in B/WF1 mice. Analysis of mixture of TA beta Z cell and B/WF1 spleen cell lysates immunoprecipitated by anti-A beta Z mAb suggested that the amount of haplotype mixed A beta Z/A alpha d molecules in B/WF1 spleen cells is less than 1/10 that of haplotype matched A beta/A alpha pairs. Our results suggest that, although undetectable by biochemical analysis, small amounts of mixed haplotype A beta Z/A alpha d molecules exist in B/WF1 spleen cells. Also, T cell clones which recognize them exists in B/WF1 mice. Because autoimmune symptoms of B/WF1 mice are shown to be related to heterozygosity at the H-2 region, autoreactive T cell clones which recognize the mixed haplotype A beta Z/A alpha d class II molecule might be involved for the induction of autoimmunity in B/WF1 mice.

Cardiopulmonary function after pulmonary lobectomy in patients with lung cancer

The effects of pulmonary lobectomy on cardiopulmonary function were investigated in 9 patients with lung cancer. Hemodynamic studies at rest and during exercise were performed before and 4 to 6 months after the operation. Differences in hemodynamics between before and after operation were observed with respect to heart rate, pulmonary arterial pressure, pulmonary vascular resistance index, and stroke volume index. Heart rate, pulmonary arterial pressure, and pulmonary vascular resistance index were significantly increased after operation, whereas stroke volume index was significantly decreased. It is thought that cardiac index was preserved by the increase in heart rate despite a decrease in stroke volume index associated with the decreased pulmonary vascular bed after the operation. When driving pressure and cardiac index were studied after operation, the pressure at rest and during exercise was higher, and the pressure-flow curve increased more steeply, as compared with the preoperative values. These results suggest a significant deterioration in cardiopulmonary function after lobectomy. As the patient characteristics were heterogeneous (five lobectomies and four bilobectomies), and their findings are limited, additional studies may be necessary in the future.

Effects of prolonged application of isoprenaline on intracellular free magnesium concentration in isolated heart of rat

1. The effect of prolonged application of isoprenaline on intracellular free-Mg2+ concentration ([Mg2+]i) was examined by use of 31P-nuclear magnetic resonance (31P-n.m.r.) in rat isolated hearts. Left ventricular pressure (LVP) was simultaneously measured. 2. [Mg2+]i was estimated from the separation of the alpha- and beta-ATP peaks, using the dissociation constant of MgATP 38 microM (established previously). In normal (phosphate-free, Krebs-Henseleit) solution, [Mg2+]i was approximately 0.4 mM. 3. When isoprenaline was applied for 100 min, a transient increase in [Mg2+]i was observed during the initial 25 min, whilst concentrations of ATP ([ATP]) and phosphocreatine ([PCr]) decreased and [Pi] correspondingly increased. During the subsequent 75 min of isoprenaline application, [Mg2+]i decreased below its resting levels. Washout of isoprenaline restored [Mg2+]i and [PCr], but [ATP] remained low. These changes elicited by isoprenaline were not observed in the presence of propranolol, a typical alpha-adrenoceptor blocker. 4. Isoprenaline increased both LVP and heart rate. The increased LVP and heart rate slowly returned to lower values during prolonged application of isoprenaline, but remained higher than those before application. 5. The transient rise in [Mg2+]i elicited by isoprenaline could be attributed to the decrease in [ATP] resulting in a release of Mg2+. The subsequent decrease in [Mg2+]i during the prolonged applications suggests that beta-adrenoceptor stimulation itself facilitates Mg(2+)-extruding mechanism(s).

Induction chemoradiotherapy followed by surgery for stage III non-small cell lung cancer

Twenty-five patients with stage III, non-small cell lung cancer were treated with cisplatin-based chemotherapy and thoracic radiation therapy followed by surgery. Thirteen patients had stage IIIA disease and 12, stage IIIB disease. The chemotherapy and radiotherapy were intensively combined with only a few days' interval between them. Radiation therapy delivering a total dose of 50-70 Gy was started 10 days after the beginning of chemotherapy. A few additional courses of chemotherapy were repeated until a thoracotomy was performed. All but two surgically-treated patients underwent tumor resection, with 19 lobectomies and four pneumonectomies. Eighteen patients underwent curative and five, non-curative resections. Pathological examination of the resected specimen provided accurate intrathoracic information. Six patients (24%) showed a pathologically complete response, with no cancer cells detected in the resected specimens. Severe postoperative complications occurred in five patients (20%), with one death. The disease recurred in five of the 18 patients who underwent a curative resection. A second primary tumor developed in two other patients. Seventeen patients (68%) are alive, with a median follow-up of 37 months after thoracotomy. The estimated three-year survival was 67% for all patients.

Angiotensin II-induced endothelium-dependent relaxation of fowl aorta

In the domestic fowl, angiotensin II (ANG II) decreases blood pressure in vivo and causes endothelium-dependent relaxation of aortic smooth muscles in vitro. To characterize ANG II-induced vasorelaxation, we compared endothelium-dependent vasodilatory effects of [Asp1,Val5]-ANG II (fowl ANG II) and acetylcholine (ACh) with the endothelium-independent vasorelaxing effect of sodium nitroprusside (SNP) on isometric tension of fowl aortic rings. Hemoglobin (Hb), gossypol, and N omega-nitro-L-arginine methyl ester (L-NAME), inhibitors for endothelium-derived relaxing factor (EDRF) in mammalian blood vessels, partially inhibited vasorelaxation induced by ANG II and ACh in fowl. Hb also markedly attenuated SNP-induced vasorelaxation, but not 8-bromoguanosine 3',5'-cyclic monophosphate-induced relaxation. 3,4,5-Trimethoxybenzoic acid 8-(diethylamino)octyl ester hydrochloride (TMB-8) or the removal of Ca2+ from the bathing medium attenuated the ACh-induced relaxation but did not significantly reduce vasorelaxation induced by ANG II or SNP. In the zero Ca2+ medium, aortic rings showed tachyphylaxis to ACh, while ANG II caused tachyphylaxis regardless of the presence or absence of external Ca2+. Furthermore, pretreatment of the ring with a high dose of ACh abolished the vasorelaxation response to ANG II, suggesting that ACh and ANG II may share a common Ca2+ pool. Calmidazolium, a calmodulin antagonist, abolished the vasorelaxation induced by ANG II and ACh but not that by SNP. Comparison of the vasodilatory effects of several ANG II analogues on fowl aortic rings showed an approximate potency order of [Asp1,Val5]-ANG II = [Asp1,Ile5]-ANG II > [Asn1,Ile5]-ANG II = [Sar1,Ile5]-ANG II > [Val5]-ANG III.(ABSTRACT TRUNCATED AT 250 WORDS)

Haemodynamic and neurohumoral changes in spontaneously hypertensive rats with aortocaval fistulae

1. Our aim was to evaluate the effects of an aortocaval fistula (1 mm) on cardiorenal haemodynamics, cardiac hypertrophy and neurohumoral factors in spontaneously hypertensive rats and to compare the results with those observed in Wistar rats at 2 weeks after fistulae placement. Sham-operated spontaneously hypertensive rats and Wistar rats served as controls. 2. Heart weight was significantly increased in spontaneously hypertensive rats (34%) and in Wistar rats (43%) at 2 weeks after fistula creation. Left ventricular systolic pressure and dp/dtmax. were significantly decreased (both P < 0.01) in spontaneously hypertensive rats with fistulae which had higher left ventricular end-diastolic pressure than Wistar rats with fistulae (P < 0.01). Signs of circulatory congestion (ascites, tachypnoea, prostration) were observed only in the overloaded spontaneously hypertensive rats (45%). Cardiac index was comparably increased in both fistulae groups due to an increase in stroke index, since heart rate was not increased. 3. Fistulae placement decreased renal blood flow and kidney weight, and increased blood urea nitrogen to a greater degree in spontaneously hypertensive rats (all P < 0.05); serum creatinine levels were unaltered. Plasma noradrenaline concentration was increased in spontaneously hypertensive rats with fistulae (P < 0.05), whereas plasma renin activity was not changed. 4. Thus, spontaneously hypertensive rats with fistulae developed overt haemodynamic signs of high-output heart failure with frequent ascites and dyspnoea, whereas most of these findings were milder or absent in Wistar rats. This model provides an opportunity to evaluate the pathophysiological and pharmacological responses in high-output heart failure.

Hemodynamic and neurohumoral responses to exercise in patients with congestive heart failure

Hemodynamic and neurohumoral responses to supine bicycle exercise were evaluated in 16 patients with congestive heart failure (New York Heart Association functional class II-III) and in 8 normal controls. We determined cardiac output by the dye-dilution method, and forearm hemodynamics by plethysmography. The patients had lower resting cardiac and stroke indexes (p < 0.05) than the normal controls. During exercise, the increase in the cardiac index due to an increase in heart rate, was less than that in the controls. Resting and exercise systemic vascular resistance indices were higher in the patients (p < 0.05). The patients had lower resting forearm blood flow and higher forearm vascular resistance (p < 0.05), and the increases during exercise were comparable in the 2 groups. However, forearm venous tone and venous pressure increased more in the patients (p < 0.05). Exercise duration was shorter in the patients (p < 0.01). Resting plasma angiotensin II and norepinephrine were similar in the 2 groups, but plasma 6-keto-prostaglandin F1 alpha and atrial natriuretic peptide were higher in the patients. During exercise, all of these neurohumoral parameters rose more in the patients than in the controls (p < 0.05). Thus, the patients exhibited impaired central and peripheral hemodynamics both at rest and during exercise. The excessive exercise responses of all of the neurohumoral factors suggest that both vasoconstrictor and vasodilator systems are activated in heart failure.

Kinetics of GLUT1 and GLUT4 glucose transporters expressed in Xenopus oocytes

The predominant mechanism by which insulin activates glucose transport in muscle and adipose tissue is by affecting the redistribution of the facilitated hexose carriers, GLUT1 and GLUT4, from an intracellular site to the plasma membrane. A quantitative analysis of this process has been hampered by the lack of reliable determinations for kinetic constants catalyzed by each of these isoforms. In order to obtain such information, each transporter was expressed in Xenopus oocytes by the injection of mRNA encoding rat GLUT1 or GLUT4. Equilibrium exchange 3-O-methylglucose uptake was measured and the data fitted to a two-compartment model, yielding Km = 26.2 mM and Vmax = 3.5 nmol/min/cell for GLUT1 and Km = 4.3 mM and Vmax = 0.7 nmol/min/cell for GLUT4. Measurement of the abundance of cell surface transporters was accomplished by two independent protocols: photolabeling with the impermeant hexose analog 2-N-4-(1-azi-2,2,2-trifluoroethyl)benzoyl-1,3-bis(D-mannos-4 -yloxy)-2-propylamine and subcellular fractionation of oocytes. Data obtained by either technique revealed that the ratio of plasma membrane GLUT1 to GLUT4 was about 4; this paralleled the relative maximal velocities for hexose transport, indicating that the turn-over numbers for the two isoforms were the same. Moreover, measurement of the concentration of exofacially disposed transporters with 2-N-4-(1-azi-2,2,2-trifluoroethyl)benzoyl-1,3-bis(D-mannos-4 -yloxy)-2-propylamine allowed calculation of the turnover number to be about 20,000 min-1. These data indicate that, at low substrate concentrations, the catalytic efficiency of GLUT4 is significantly greater than GLUT1. Extrapolation to mammalian systems suggests that GLUT4 is responsible for virtually all of the hexose uptake in insulin-responsive targets, particularly in the presence of hormone.

Are diabetic hearts more resistant to ischemia/reperfusion injury?

The present study was designed to investigate the cardiac impairment during ischemia/reperfusion injury in rats with streptozotocin-induced diabetes vs controls. Male rats were divided into three groups: controls, one-week diabetic rats (1wDM) and four-week diabetic rats (4wDM). In the isolated working heart, left ventricular developed pressure (LVDP), left ventricular end-diastolic pressure (LVEDP), and maximum positive and negative dP/dt were measured before ischemia and after 20 min of global ischemia followed by 30 min reperfusion. In the pre-ischemic state, hearts of 4wDM showed a significant (p < 0.05) depression of the maximum positive and negative dP/dt compared with those of controls and 1wDM. There were no significant differences in LVDP and LVEDP among the three groups. The incidence of reperfusion-induced ventricular fibrillation (VF) was 75% for controls, 15% for 1wDM rats, and 27% for 4wDM rats. In hearts without reperfusion-induced VF, there were no differences in the three groups, between the pre- and post-ischemic values in LVDP, LVEDP, and maximum positive and negative dP/dt. These findings suggest that diabetic hearts exhibit no susceptibility to ischemia/reperfusion injury.

[Twenty one multicentral studies on prognosis of advanced ovarian cancer; focused on correlation between primary surgical procedure following adjuvant chemotherapies and 4 year survival rates]

The treatment outcome of 778 patients with stage III ovarian cancer treated by surgery and chemotherapy between 1976 and 1990 in 21 institutions was analyzed retrospectively. Survival of patients treated between 1985 and 1990 was significantly superior to that before 1985 (Kaplan-Meier, p < 0.01). Four year survival rates were found to be distributed from 5 to 52% among institutions (p < 0.001, log-rank test). When survival rates were compared according to the relative dose intensity (RDI) of CDDP administered, patients who were given CDDP RDI > or = 0.9 had a favorable prognosis. The twenty-one institutions were divided into two groups: Standard (total abdominal hysterectomy and bilateral salpingo-oophorectomy) vs. standard+debulking (of as much gross tumor as can safely be performed) according to the operative procedure which was performed in each hospital. It was found that the four-year survival rate for patients treated in hospitals where standard surgery was done was 22.9 +/- 12.2%, whereas that in hospitals adopting standard+debulking surgery was 34.4 +/- 10.1% (p = 0.03, t-test). When the hospitals were divided into 4 groups according to combination of the operative procedure and CDDP RDI, the four year survival rates were 17.5 +/- 8.3% for standard+debulking+CDDP RDI < 0.9, 39.0 +/- 1.4% for standard+CDDP RDI > or = 0.9, 28.8 +/- 11.5% for standard+debulking+CDDP RDI < 0.9 and 37.8 +/- 8.0% for standard+debulking+CDDP RDI > or = 0.9.(ABSTRACT TRUNCATED AT 250 WORDS)

Lisinopril reduces cardiac hypertrophy and mortality in rats with aortocaval fistula

We evaluated the effects of lisinopril (1 mg/kg per day) on hemodynamics, cardiac hypertrophy, and neurohumoral factors in Wistar rats with an abdominal aortocaval fistula. After 4 weeks of treatment, the results were compared with values obtained for untreated rats with a fistula and for sham-operated rats. Volume loading induced biventricular hypertrophy, hemodynamic signs of high-output heart failure (increased cardiac output, left ventricular end-diastolic pressure, and pulse pressure), and impaired renal function (decreased renal blood flow and kidney weight; increased blood urea nitrogen). Lisinopril did not affect these cardiorenal hemodynamics, but decreased left ventricular mass and mortality rate (both P < 0.05). Lisinopril attenuated the increase in plasma norepinephrine, and increased plasma renin activity (both P < 0.05). Thus, lisinopril reduced left ventricular mass and mortality in rats with high-output heart failure without changing the cardiorenal hemodynamics. Neurohumoral inhibition may play a role in the beneficial effects of lisinopril.

Distinction of mouse CD8+ suppressor effector T cell clones from cytotoxic T cell clones by cytokine production and CD45 isoforms

Mouse CD8+ T cell clones could be subdivided into two subgroups by the pattern of cytokine production and CD45 isoforms that exactly corresponded with the functionally assigned cytotoxic (CTL) and suppressor (Ts) subsets. All the Ts clones invariably produced IL-10 after stimulation with immobilized anti-CD3, whereas none of CTL clones expressed mRNA of IL-10 by the same stimulation. All the CTL clones were positive for CD45RA Ag, a product of exon 4 of CD45 gene, whereas none of the Ts clones were positive for this Ag. The results are analogous to the situation within CD4+ T cell clones in which Th1 and Th2 subtypes can be distinguished by CD45 isoforms and cytokines they produce. Ts clones could suppress the proliferative responses of both Th1 and Th2 type CD4+ clones by the production of two different cytokines, IL-10 and IFN gamma, respectively, but none of the CTL clones could suppress the proliferation of CD4+ T cells. The participation of an additional nonspecific molecule in the suppression of antibody response is suggested.

Distinction of mouse CD8+ suppressor effector T cell clones from cytotoxic T cell clones by cytokine production and CD45 isoforms

Mouse CD8+ T cell clones could be subdivided into two subgroups by the pattern of cytokine production and CD45 isoforms that exactly corresponded with the functionally assigned cytotoxic (CTL) and suppressor (Ts) subsets. All the Ts clones invariably produced IL-10 after stimulation with immobilized anti-CD3, whereas none of CTL clones expressed mRNA of IL-10 by the same stimulation. All the CTL clones were positive for CD45RA Ag, a product of exon 4 of CD45 gene, whereas none of the Ts clones were positive for this Ag. The results are analogous to the situation within CD4+ T cell clones in which Th1 and Th2 subtypes can be distinguished by CD45 isoforms and cytokines they produce. Ts clones could suppress the proliferative responses of both Th1 and Th2 type CD4+ clones by the production of two different cytokines, IL-10 and IFN gamma, respectively, but none of the CTL clones could suppress the proliferation of CD4+ T cells. The participation of an additional nonspecific molecule in the suppression of antibody response is suggested.

Reduced renal arterial perfusion pressure stimulates renin release from domestic fowl kidneys

Systemic hypovolemia and hypotension increase plasma renin activity (PRA) in fowl, but it is not clear whether this response is mediated directly by reduced renal arterial perfusion pressure (RAPP) or indirectly via renal nerves activated when systemic baroreceptors detect hypotension. To evaluate the influence of RAPP on renin release, arterial and renal venous blood samples were collected as RAPP was reduced step-wise from 108 mm Hg (control) to 71 and 47 mm Hg. PRA in systemic arterial (aPRA) and renal venous (vPRA) plasma was measured as the rate of fowl angiotensin I (ANG I) generation. Basal vPRA (2.47 +/- 0.6 ng x ml-1 x min-1) tended to be higher than aPRA (1.24 +/- 0.3 ng x ml-1 x min-1). When RAPP was reduced to 47 mm Hg both vPRA (4.35 +/- 0.6 ng x ml-1 x min-1) and aPRA (1.91 +/- 0.3 ng x ml-1 x min-1) increased significantly. Significant negative slopes (P = 0.01) were obtained when changes in aPRA or vPRA were regressed on RAPP. Mean systemic arterial pressure did not change during reductions in RAPP, nor did angiotensinogen concentrations differ when systemic arterial (472 +/- 30 ng/ml) and renal venous (460 +/- 27 ng/ml) plasma values were compared. Renal plasma flow was fully autoregulated as RAPP was reduced from 108 to 47 mm Hg; consequently, RAPP-induced increases in vPRA cannot be attributed to hemoconcentration of secreted renin. These results demonstrate that reductions in RAPP directly stimulate renin release from domestic fowl kidneys.

[Magnetization transfer contrast imaging of the skeletal muscle in gradient recalled echo sequence]

The human midcalf muscle images were obtained using gradient recalled echo (GRE) sequence with and without magnetization transfer contrast (MTC) sequence. A significant decrease of relative signal intensity was observed in muscle with off-resonance irradiation. The percentage increase of signal intensity after dorsiflexion exercises was 55.6% and 29.0% for MTC-GRE and GRE sequence, respectively. MTC technique might be useful in improving contrast between many tissues as well as muscles.

[Etoposide/cis-platinum (CDDP) combined chemotherapy for ovarian cancer: evaluation of optimum schedule for CDDP administration in chronic continuous exposure of ovarian cancer cells to low-dose etoposide in vitro]

Combined chemotherapy with etoposide and cis-platinum (CDDP) is considered a second line regimen for refractory cases of ovarian cancer. In addition to the time-dependent cytocidal kinetic of etoposide, much attention has been paid to low-dose continuous administration of etoposide. In this study, ovarian cancer cells (SHIN-3) were continuously exposed to low-dose etoposide in vitro to determine the optimum schedule for CDDP administration. Etoposide concentrations of 1-3 micrograms/ml were used; per os administration of etoposide at 25 mg x 2/day has been shown to produce a continuous plasma concentration of etoposide of around 1 microgram/ml. The results were as follows: 1) The IC50 of CDDP after 72 hours of exposure was 8.0 micrograms/ml and that of etoposide after 114 hours was 3.0 micrograms/ml. 2) After 100 hours of exposure to 1 microgram/ml of etoposide, cell cyclic phase analysis showed cells predominantly in G2/M phase arrest. 3) After 24-hour administration of CDDP, it was more than 24 hours before a cytocidal effect was observed. 4) During continuous exposure of SHIN-3 to etoposide (1 microgram/ml) for 6 days, CDDP was added on the 1st, 3rd, and 5th days. The largest ratio of growth inhibition with combined treatment to that with CDDP alone was attained on the 5th day. We conclude that, in combination regimens using low-dose continuous etoposide, CDDP should be added after etoposide administration is begun.

[A new operational method of functional neurosurgery combining micro-recording and MRI stereotaxy for the treatment of Parkinson's disease]

We have developed a new operational method for stereotactic functional neurosurgery using MRI stereotaxy combined with microelectrode recording. MRI stereotaxy shows us the individual variations of thalamic configurations. The tentative target points were determined using the MRI stereotaxy assisted software system which revised the distortion of MRI images. Consequently, the accuracy and safety of the microelectrode recording were increased. This, in turn, increased the accuracy of stereotactic thalamotomy while producing encouraging operational outcomes. The effectiveness of stereotactic thalamotomy for Parkinson's disease was confirmed by these excellent operative results. The symptoms improved and the dosage of medications, including L-DOPA, decreased. Furthermore, our results indicate that the distributing area of deep sensory neurons in the thalamus extended more posteriorly and upward than previously expected. Therefore, the functional and anatomical similarity between the human and monkey thalamus was reaffirmed. In this report, based on the above data, we reevaluated the neural mechanism of tremor and the role of stereotactic functional neurosurgery for Parkinson's disease.

Characterization of factors that suppress linear DNA replication in SV40 in vitro replication system

The in vitro simian virus 40 (SV40) replication system has been developed as a model system of cellular DNA replication, because the replication initiated from the replication origin of SV40 and replication fork proceeds bidirectionally. In this system, SV40 T-antigen (TAg) is the only factor provided by viral genes, while all other factors are supplied by the host cells. A suppression of replication has been observed in the linear template containing SV40 replication origin, compared with the closed circular template in the SV40 in vitro replication system using a crude extract of HeLa cells. However in the in vitro replication system reconstituted from partially purified factors, less preference was observed for the replication of the closed circular DNA over the linear DNA. In a mono-polymerase system supplemented by crude extracts, a suppression of replication in a linear template was also observed, when compared with a closed circular template. This suppression effect of crude extract was abolished by heat treatment, suggesting that the suppression was induced by some protein factors. A crude extract of HeLa cells was fractionated by stepwise elution with buffers containing 0.2 M, 0.4 M, 0.6 M and 1 M NaCl on a phosphocellulose column, and characterization of factors that suppress linear DNA replication has been done. Both fractions that were eluted at 0.4 M and 0.6 M from phosphocellulose were necessary to suppress linear DNA replication efficiently. The factors in the 0.6 M fraction that suppressed linear DNA replication synergistically with the 0.4 M fraction were partially purified by successive chromatography with heparin-sepharose and dsDNA-cellulose followed by glycerol gradient centrifugation. These results suggested that multiple factors are required to suppress DNA replication of the linear template.

Statistical mechanical approach for predicting the transition to non-B DNA structures in supercoiled DNA

Supercoiling causes global twist of DNA structure and the supercoiled state has wide influence on conformational transition. A statistical mechanical approach was made for prediction of the transition probability to non-B DNA structures under torsional stress. A conditional partition function was defined as the sum over all possible states of the DNA sequence with basepair 1 and basepair n being in B-form helix and a recurrence formula was developed which expressed the partition function for basepair n with those for less number of pairs. This new definition permits a quick enumeration of every configuration of secondary structures. Energetic parameters of all conformations concerned, involving B-form, interior loop, cruciform and Z-form, were included in the equation. The probability of transition to each non-B conformation could be derived from these conditional partition functions. For treatment of effects of superhelicity, supercoiling energy was considered, and a twist of each conformation was determined to minimize the supercoiling energy. As the twist itself affects the transition probability, the whole scheme of equations was solved by renormalization technique. The present method permits a simultaneous treatment of several types of conformations under a common torsional stress. A set of energetic parameters of DNA secondary structures has been chosen for calculation. Some DNA sequences were submitted to the calculation, and all the sequences that we submitted gave stable convergence. Some of them have been investigated the critical supercoil density for the transition to non-B DNA structures. Even though the reliability of the set of parameters was not enough, the prediction of secondary structure transition showed good agreement with reported observation. Hence, the present algorithm can estimate the probability of local conformational change of DNA under a given supercoil density, and also be employed to predict some specific sequences in which conformational change is sensitive to superhelicity.