Vitamin E succinate inhibits proliferation and migration of retinal pigment epithelial cells in vitro: therapeutic implication for proliferative vitreoretinopathy

BACKGROUND

Retinal pigment epithelial (RPE) cells play an important role in proliferative vitreoretinopathy (PVR). Vitamin E succinate is an ester form of a potent biological antioxidant, vitamin E, and has unique effects on various cells. We examined the effect of vitamin E succinate on proliferation and migration of cultured bovine RPE cells, since these are critical steps in the development of PVR.

METHODS

Bovine RPE cells were cultured in minimal essential medium (MEM) containing 10% fetal calf serum (MEM-10). Cells were incubated with MEM-10 containing 25 microM vitamin E, vitamin E succinate, butylated hydroxytoluene (BHT) or d-mannitol. Cell proliferation was assessed by counting cell numbers on days 2, 4 and 6. 3H-Thymidine uptake was also examined in RPE cells incubated with various forms of vitamin E-- vitamin E, vitamin E succinate, Trolox, gamma-tocopherol, vitamin E acetate, vitamin E phosphate, vitamin E nicotinate--or antioxidants-- BHT or d-mannitol (25 microM each). RPE cell migration was studied as follows: A small area (5 x 15 mm) of confluent cultured RPE cells was denuded using a straight razor blade and incubation was continued for 20 h with MEM-10 containing vitamin E, vitamin E succinate, gamma-tocopherol or BHT. The number of cells that migrated into the denuded area from the wound edge in each microscopic field (x20) was counted and expressed as a percentage of control (MEM-10 alone).

RESULTS

The antioxidants, vitamin E and BHT, stimulated RPE cell proliferation and 3H-thymidine incorporation compared with the control, while vitamin E succinate significantly inhibited both proliferation and 3H-thymidine uptake (IC50, 23 microM). Other forms of vitamin E or d-mannitol had no effect. Neither vitamin E nor BHT had a significant effect on RPE cell migration (108.2% and 112.6% of control, respectively), but vitamin E succinate inhibited migration (58.3%). Cell viability, assessed by the trypan blue dye exclusion test, was not impaired by a 3-day incubation with 50 microM of vitamin E succinate.

CONCLUSIONS

An ester form of a physiological antioxidant, vitamin E succinate, inhibits RPE cell proliferation and migration without causing cellular toxicity. These findings suggest its therapeutic potential for the pharmacological treatment of PVR.

Effect of hyperthermia on proliferation and deviation of carcinoembryonic antigen and squamous cell carcinoma-related antigen of human esophageal carcinoma cells in culture

As a basic study of hyperthermia on malignant tumors, we investigated the kinetics of proliferative activity and the values of tumor markers carcinoembryonic antigen (CEA) and squamous cell carcinoma-related antigen (SCC) in a human esophageal carcinoma cell line, SGF-4, following a change of culture temperature. The temperature range allowing cultured SGF-4 cells to proliferate was from 37 degrees C to 40 degrees C. In an experiment examining the recovery of proliferative activity, no proliferative activity was observed after the cultured cells were exposed to 42 degrees C for 72 hours. The values of CEA and SCC as tumor markers were found to be increased in association with the cell damage due to the change of temperature. These markers could thus be useful as indicators for evaluations of hyperthermia therapy effectiveness.

Simplified technique for hemi-arch replacement during open distal anastomosis: the "calla" method

During open distal anastomosis for type A dissecting aneurysm, the beveled end of the graft was rolled back like a bract of the Calla flower and inserted into the aortic lumen. The inverted graft was anastomosed using forehand continuous sutures. After completion of the distal anastomosis, the inverted graft was pulled out and then the proximal anastomosis was completed. This "Calla flower" deformation facilitates the hemostatic distal anastomosis in hemi-arch replacement during open distal anastomosis.

Hypericin inhibits cell growth and induces apoptosis in retinal pigment epithelial cells: possible involvement of protein kinase C

Proliferative vitreoretinopathy (PVR) is characterized by the proliferation and migration of retinal pigment epithelial (RPE) cells in the vitreous cavity. The drug hypericin, which is already in clinical use as an antidepressant, has shown promise as an antiviral and antineoplastic agent. To investigate the therapeutic potential of hypericin in PVR, we incubated RPE cells in standard medium with various serum concentrations containing 0.5 to 5 microM hypericin. In some experiments we studied the effects of hypericin in conjunction with the RPE growth stimulating cytokine tumor necrosis factor alpha (TNF-alpha). Dose-dependent inhibition of RPE cell proliferation with IC50 values of 0.7 microM and 3.3 microM in 1% and 5% serum respectively, was found. Even in conjunction with TNF-alpha, hypericin inhibited RPE proliferation with an IC50 value of 1.5 microM. The drug inhibited PKC activity in cells treated with a 2.5 microM dose by 72% after 30 min and by 100% after 180 min. Finally, hypericin induced RPE cells to undergo apoptotic cell death, as shown by the presence of DNA laddering. These results suggest that hypericin may have potential as a therapeutic drug for PVR and that its antiproliferative and apoptotic effects on RPE cells in vitro are in part mediated by PKC.

Monitoring the native cardiac output during femoral venoarterial cardiopulmonary bypass support

To manage postcardiotomy patients with cardiopulmonary bypass support (CPS), it is very important to evaluate the native cardiac function. In 5 postcardiotomy cases without CPS, the alternative thermodilution outputs by right ventricular (RV) injection were compared with simultaneous thermodilution outputs by standard right atrial (RA) injection. Cardiac output determined by RV injections, ranging from 3.4 to 10.1 L/min, showed close agreement with the values by RA injections (r = 0.993). Four cases with postcardiotomy profound heart failure were placed on femoral venoarterial CPS and managed with monitoring native cardiac output determined by an RV injection thermodilution method. It was very easy and reasonable to decide the pump flow relative to native cardiac output. The cardiac output determined by RV injection provides a means of accurate evaluation for the failing heart in postcardiotomy cases with venoarterial CPS and optimizes the staged weaning off CPS or the change to a pneumatic pulsatile ventricular assist device for long-term assist.

Changes of intraaortic balloon volume during pumping in a mock circulation system

The effects of hemodynamic changes on intraaortic balloon (IAB) volumes were studied experimentally using a helium tachometer in a mock circulatory system. The IAB volume decreased with increases in the heart rate and mean aortic pressure, but the degree of reduction in the IAB volume was different among 4 commercially available IAB drivers. Improvements in IAB consoles are needed to compliment the progress made in percutaneous techniques for IAB insertion resulting in smaller balloons.

Comparison of in vitro antiproliferative effects of steroids and nonsteroidal antiinflammatory drugs on human keratocytes

Corticosteroids are currently administered after photorefractive keratectomy (PRK) to reduce corneal haze and myopic regression, However the beneficial effects of corticosteroids are controversial, and they are associated with many side effects. In this study we compared the in vitro antiproliferative effects of nonsteroidal antiinflammatory drugs (NSAIDs), diclofenac and flurbiprofen, with those of dexamethasone on human keratocytes. Human keratocytes were incubated with various concentrations of diclofenac, flurbiprofen, and dexamethasone. The control samples were incubated under the same conditions except for the absence of drugs. Proliferation of the keratocytes was measured by [3H]thymidine uptake into DNA on days 1, 2, and 4. Diclofenac was the most potent agent, inducing dose-dependent inhibition at concentrations > or = 10(-1) mM on days 1 and 2 and > or = 10(-5) mm on day 4. Flurbiprofen followed closely, inhibiting keratocytes at and above 1 mm on day 1, 10(-1) mm on day 2, and 10(-4) mm on day 4. Dexamethasone was the least effective, exhibiting inhibition at and above 25 mM on day 1, 5 mM on day 2, and 1 mM on day 4 (Wilcoxon rank sum test, P < or = 0.05). The ID50S reflect the same trend (day 4: diclofenac = 0.03 mM, flurbiprofen = 0.2 mM, dexamethasone = 3.2 mM). In addition, diclofenac and dexamethasone showed time-dependent antiproliferative effects. These results indicate that NSAIDs are more potent than corticosteroids in inhibiting proliferation of human keratocytes in vitro, and suggesting a potential use of NSAIDs in modulating corneal wound healing after PRK.

Histologic findings and prognosis of uveal malignant melanoma in japanese patients

PURPOSE

To determine factors of uveal malignant melanoma that would help to predict prognosis in Japanese patients.

METHODS

From 1969 to 1994, 23 eyes with uveal malignant melanoma were enucleated from 23 Japanese patients, and 16 of these patients were studied. In the 16 patients, enucleated eyes were evaluated for tumor characteristics, including cell type and microvascular architecture. Patient records were reviewed for follow-up therapy and outcome. Mortality rate was evaluated four years after enucleation.

RESULTS

In Japanese patients with uveal malignant melanoma, the average tumor size was larger (average largest diameter, 11.36 mm; average increase, 6.25 mm) and the average patient age was younger (55.2 years old) than previously reported for white populations. Patients with spindle cell type melanoma tended to have a better prognosis than those with epithelioid cell type (four-year mortality rates: spindle cell type, 0%; mixed cell type, 43%; epithelioid cell type, 66%). Microvascular architecture patterns interpreted as either network or closed loop patterns were associated with a poorer prognosis (network pattern, P = .03; closed loop pattern, P = .005).

CONCLUSIONS

The prognosis for Japanese patients with uveal malignant melanoma is poorer, and epithelioid cell-type melanoma is more common, than has been reported in white populations. Mitotic figures are well correlated with poor prognosis, as are two microvascular patterns, the network pattern and the closed loop pattern.

Lack of a role for bradykinin in allergen-induced airway microvascular leakage and bronchoconstriction in the guinea pig

We have investigated the role of bradykinin in allergen-induced airway microvascular leakage and bronchoconstriction in sensitized guinea pigs. We used a selective bradykinin B2 receptor antagonist, HOE140, which has been shown to prevent the airway effects induced by bradykinin. Lung resistance (RL) was measured for 6 min after challenge with allergen. Extravasation of Evans blue dye into airway tissues was used as an index of the airway microvascular leakage. Aerosolized ovalbumin (5 mg/ml, 30 breaths) induced a significant increase in RL and leakage of dye in the trachea, main bronchi and intrapulmonary airways in the ovalbumin-sensitized guinea pigs. HOE140 given by inhalation (200 microM, 60 breaths) had no effect on the airway microvascular leakage and bronchoconstriction induced by the allergen. I.v. HOE140 (200 nmol/kg) did not significantly inhibit these airway responses. We conclude that bradykinin-mediated mechanism may not play a significant role in airway microvascular leakage or bronchoconstriction induced by allergen.

Effects of right ventricular failure on renal function during pneumatic left ventricular assist

In an experiment dog model of acute biventricular failure, the effects of left ventricular (LV) assist on renal hemodynamics and function were evaluated. After the induction of severe cardiac failure by multiple ligation of the coronary arteries, LV assist with a 40 ml pneumatic pulsatile pump was initiated, and the aortic flow was maintained at control values. The right atrial pressure (RAP) rose to 21.3 mm Hg with the appearance of profound right ventricular (RV) failure. Renal arterial blood flow (RAF) decreased to about 60% of the control value after 2 h of LV assist. The urine volume decreased and renal function deteriorated progressively. RV assist decreased the RAP to 4.8 mm Hg, and the reduced RAF recovered. After 3 h of RV assist, the RAF returned to initial values and the urine volume increased, but renal function did not recover. Advanced biventricular failure with elevated RAP during LV assist reduced renal perfusion and impaired renal function and may be an indication for early RV assist.

Hair analysis for drugs of abuse XII. Determination of PCP and its major metabolites, PCHP and PPC, in rat hair after administration of PCP

We developed an analytical method for the simultaneous detection of phencyclidine (PCP) and its metabolites, 4-phenyl-4-piperidinocyclohexanol (PPC) and 1-(1-phenylcyclohexyl)-4-hydroxypiperidine (PCHP), in rat hair. Three pigmented, hairy rats were intraperitoneally administered PCP hydrochloride (HCl) at 0.05-0.5 mg/kg once a day for 10 successive days. Animal hair was shaved just before the first administration, and the newly grown hair was collected 4 weeks after the first administration. After the rat hair sample was washed three times with 0.1% sodium dodecyl sulfonate and water, separately, and dried in a desiccator, 20 mg of finely cut hair was extracted with 2 mL methanol-5N HCl (20:1) under ultrasonication for 1 h, followed by storage at room temperature for 14 h. Following filtration and evaporation of the extract, it was purified with Bond Elut Certify in the usual manner, and the extract was derivatized with N,O-bis(trimethylsilyl) acetamide for gas chromatographic-mass spectrometric analysis using deuterated PCP, PPC, and PCHP as internal standards. The selected ions were monitored at m/z 186, 200, and 242 for PCP, m/z 172, 288, and 331 for trimethylsilyl (TMS) PCHP, and m/z 200, 254, and 331 for TMS PPC. PCP, PCHP, and PPC were simultaneously detected in the rat hair down to 0.1 mg/kg PCP HCl. Even at the dose of 0.05 mg/kg, PCP was clearly detected in the rat hair. Based on the area under the concentration versus time curve (AUC) in plasma (1460 ng.min/mL), the PCP concentration (3.34 ng/mg) in the rat hair was quite high. The incorporation rates into hair (concentration in hair/AUC) of PCP, PCHP, and trans-PPC were 2.29, 1.65, and 0.50, respectively, at 0.5 mg/kg. Our results suggest that hair could be a useful specimen for confirmation of active past PCP use because PCP and its metabolites can be detected simultaneously.

Intraoperative myogenic motor evoked potentials induced by direct electrical stimulation of the exposed motor cortex under isoflurane and sevoflurane

We monitored myogenic motor evoked potentials (MEPS) during intracranial surgery in 21 patients anesthetized with nitrous oxide in oxygen, fentanyl, and 0.75-1.5 minimum alveolar anesthetic concentration (MAC) isoflurane (n = 11) or sevoflurane (n = 10). The exposed motor cortex was stimulated with a single or train-of-five rectangular pulses at a high frequency (500 Hz), while the compound muscle action potentials (CMAPS) were recorded from the abductor pollicis brevis muscle. Neuromuscular block was monitored by recording the CMAPs from the abductor pollicis brevis muscle in response to electrical stimulation of the median nerve at the wrist (M-response). Stimulation of the motor cortex with a single pulse elicited MEPs in none of the patients, while stimulation with a train-of-five rectangular pulses at high frequency elicited MEPs in all patients. The relationship between MEP amplitude and the level of neuromuscular block induced by vecuronium infusion was evaluated in seven patients. For comparison of the individual measurements, the MEP amplitude at a M-response amplitude of 100% was calculated by means of the individual regression curve as 100% of MEP amplitude. There was a linear correlation between percent MEP amplitude and percent M-response amplitude (r = 0.81; P < 0.01). Intraoperative monitoring of MEP could be performed at a M-response amplitude above 90 % of the baseline value in 10 patients and at a M-response amplitude of 20%-50% of the baseline value in 11 patients. During monitoring of the 21 patients, MEPs did not change in 18 patients and disappeared in two patients. In the remaining patient, MEP amplitudes were attenuated to approximately 10% of the baseline value and recovered after cessation of surgical manipulation. In the two patients in whom MEPs disappeared, motor paresis developed postoperatively. We conclude that 1) intraoperative myogenic MEP monitoring is feasible during isoflurane or sevoflurane anesthesia if stimulation is performed with a short train of rectangular pulses, and 2) that electromyographic monitoring of neuromuscular block is useful to assess intraoperative MEP changes under partial neuromuscular block.

Effect of niceritrol on fibrinolysis and lipoprotein (a) levels in patients with coronary artery disease

BACKGROUND

Lipoprotein (a) [Lp(a)] is an independent risk factor for coronary artery disease and niceritrol (a prodrug of nicotinic acid) is known to reduce Lp(a) levels. Patients with coronary artery disease often have impairment of the fibrinolytic system.

METHODS

To elucidate the effect of niceritrol on fibrinolysis and Lp(a) levels, we examined plasminogen activator inhibitor (PAI) activity, tissue-type plasminogen activator (t-PA) antigen, and serum Lp(a) levels before and after administration of niceritrol to coronary artery disease patients with high baseline Lp(a) levels (> or = 20 mg/dl). Niceritrol was administered to 26 patients for 12 weeks at 750 mg/day. Fasting blood samples were obtained at 0800 h from each patient before treatment, after administration of niceritrol for 12 weeks and 4 weeks after the discontinuation of therapy.

RESULTS

There were significant reductions in PAI activity (9.9 +/- 1.8 compared with 5.4 +/- 1.6 IU/ml, P < 0.01), t-PA antigen levels (10.0 +/- 0.5 compared with 8.8 +/- 0.6 ng/ml, P < 0.05), and Lp(a) levels (49.3 +/- 5.9 compared with 42.5 +/- 5.4 mg/dl, P < 0.01) after 12 weeks of niceritrol administration. Four weeks after the discontinuation of niceritrol treatment, all these parameters returned to baseline.

CONCLUSIONS

This study demonstrated that niceritrol administration decreases PAI activity and t-PA antigen levels together with Lp(a) levels in patients with coronary artery disease. These observations suggest that niceritrol administration may tend to normalize fibrinolysis in such patients.

Management of subarachnoid fluid collection in infants based on a long-term follow-up study

We report the natural history and management of subarachnoid fluid collections in infants and their management based on a longterm follow-up study in 20 cases. These subarachnoid fluid collections were resolved spontaneously in 17 of 20 patients and only 3 by surgical intervention at the age of 2. In our 20 patients the natural history of subarachnoid fluid collection in infants was benign unless the patients sustained head trauma. Surgical treatment was performed in the cases where a subarachnoid fluid collection developed into a subdural haematoma. Head trauma may precipitate subdural haematoma in patients with subarachnoid fluid collection. All patients except one who underwent the placement of subdural-peritoneal shunt, attained normal psychomotor development in time. During the follow-up period of 3 to 10 years after resolution of the fluid collection, no patient has had a recurrence once it resolved.

[Otoacoustic emissions of full-term and preterm neonates]

Transiently evoked otoacoustic emission (TEOAE), distortion product otoacoustic emission (DPOAE), and spontaneous otoacoustic emission (SOAE) were measured in 45 full-term neonates (68 ears) and 12 preterm neonates (20 ears) with ILO88 & 92. Measurements were performed in the nursery of the obstetrics ward or NICU (not sound proof room) under natural sleeping condition after nursing. No sedating agent was used. TEOAEs were rated "good response" in 61 (89.7%) of 68 full-term neonate ears. DPOAEs were rated "good response" in 40 (71.4%) of 56 full-term neonate ears. SOAEs were detectable in 25 (62.5%) of 40 full-term neonate ears. Considering the high positive rate of TEOAE in full-term neonates and the easy and noninvasive method of measurement, we concluded that TEOAE is useful for auditory screening in neonates. There was failure to detect TEOAEs in 7 ears and the measurements were all performed within 6 days after birth. Some reports claim that residual amnion in the external auditory canal or the middle ear in the first few days after birth causes slight hearing loss. Thus, we expected that making the measurements more than 7 days after birth might yield higher "good response" rates. We sometimes found that the Total Echo Powers of TEOAEs were reduced by the poor condition of the ear probe. Thus, we must be very careful in regard to this technical problem in order to perform accurate examinations. Because of its lower "good response" rate, DPOAE was not as useful for screening as TEOAE. Because of the movements or respiratory noises of the newborn infants, it was hard to detect reliable DPOAEs, particularly in the low frequency range. On the other hand, because of its frequency specificity, particurally at high frequencies, DPOAE will be useful for detecting the partial hearing impairment such as congenital high-tone hearing impairment. It would be difficult to use SOAE as a clinical test. Because it is not an evoked response, its mechanism of generation is not well understood. We expect that following longitudinal changes in SOAE in neonates may yield some information about it. We measured mainly TEOAE in preterm neonates because we had to complete the measurements as soon as possible. High Total Echo Powers of TEOAEs were recorded in most infants over 38 weeks of PCA (post conceptional age). The earliest case showed reliable TEOAE at 35 weeks PCA. In most cases that could be measured twice on different days, the Total Echo Powers of TEOAE, were higher in the second time. We therefore concluded that TEOAE might serve as an examination for monitoring the maturation of preterm neonate hearing.

Logistic character of myocardial twitch force curve: simulation

We found that the isovolumic pressure-time curve of the canine left ventricle closely fitted the difference of two logistic function curves and that the isovolumic relaxation-pressure curve segment was more reliably characterized by a logistic time constant than by the conventional exponential time constant. We therefore hypothesized that the calcium (Ca) transient and the Ca-troponin (Tn) binding and crossbridge (CB) kinetics underlay the logistic character of the ventricular isovolumic pressure curve. We tested this hypothesis with a computer simulation of a simple Ca and CB kinetics model of myocardial isometric twitch force development. We assumed the instantaneous number of attached CBs that was theoretically given as the difference between the cumulative CB attachment and detachment curves. We radically changed the Ca transient, Ca-Tn binding, and CB kinetic parameters. We always found that both the cumulative CB attachment and detachment curves closely fitted logistic functions. The difference curve of these two best-fit logistic functions closely fitted the theoretical F curve with certain combinations of the Ca transient, the Ca-Tn binding, and the CB kinetic parameters. These results seem to support our hypothesis.

Effects of hCRH on sleep and body temperature rhythms

We investigated the effects of human corticotropin-releasing hormone (hCRH) on the sleep structure and body temperature rhythms of seven healthy young men. Polysomnographic recordings were obtained and body temperatures were monitored continuously for 48 h in each subject following the intravenous administration of saline or of 100 micrograms hCRH. The administration of hCRH was associated with a significant phase-advancement in body temperature rhythm vs the saline control. The administration of hCRH affected non-rapid eye movement (NREM) sleep by reducing significantly slow wave sleep (SWS) and sleep efficiency, whereas the percentage of sleep stages 1 and 2 were increased significantly. These changes in body temperature rhythms and sleep structure induced by hCRH resembled those observed in patients with endogenous depression, except for the findings during rapid eye movement (REM) sleep. We hypothesize that a hypersecretion of hCRH in patients with endogenous depression may help to explain the changes in body temperature rhythms and sleep structure often reported in such patients.

Bystander effect caused by suicide gene expression indicates the feasibility of gene therapy for hepatocellular carcinoma

In the field of gene therapy using retroviral vectors, it appears impossible to introduce a foreign gene into all target cells. Therefore adjacent cell killing, the socalled bystander effect, caused by genetically modified cells provides therapeutic advantages for gene therapy against cancers. We retrovirally transduced the herpes simplex virus thymidine kinase (HSV-tk) gene into murine and rat hepatocellular carcinoma (HCC) cells. These HSV-tk gene-transduced HCC cells were cocultured with the corresponding parental cells in the presence of ganciclovir, at a concentration not at all cytotoxic to the parental cells. When parental HCC cells were cocultured with their HSV-tk gene-transduced counterparts at a high density at which most cells were in contact with one another, they were markedly eliminated. Conversely, when cocultured at a low density at which none of the cells were in contact, a weak but statistically significant bystander effect was observed. Addition of lysates of HSV-tk gene-transduced cells in the presence of ganciclovir did not cause and killing of parental cells. Furthermore, media conditioned by transduced cells with ganciclovir exhibited weak cytotoxic effects on parental cells. These results indicate that cell-cell contact plays a major causative role in the bystander effect and that minor contributors to this phenomenon are some cytotoxic substance released from transduced cells. Importantly, the bystander effect was induced in vivo as well as in vitro. When mixtures of transduced and untransduced HCC cells were implanted into the flank region of mice, intraperitoneal ganciclovir administration considerably inhibited tumor development, indicating the feasibility of gene therapy with HSV-tk gene and ganciclovir against HCC.

Monoclonal antibody against the polymorphic site distinguishes apolipoprotein E4 from other isoforms

Apolipoprotein E4 has been confirmed as a genetic risk factor for Alzheimer's disease. Although several hypotheses have been advanced to explain how the inheritance of apolipoprotein E isoforms affects the rate of Alzheimer's disease expression, the mechanism whereby apolipoprotein E is involved in the pathogenesis of Alzheimer's disease is still uncertain. To clarify the way in which the apolipoprotein E4 isoform differs from the others, we generated a monoclonal antibody specifically reactive with the apolipoprotein E4 isoform. This antibody suggests that the polymorphic site is important in differentiating the ApoE4 isoform from others.

Serial changes of plasma plasminogen activator inhibitor activity in acute myocardial infarction: difference between thrombolytic therapy and direct coronary angioplasty

The fibrinolytic system is impaired in patients with acute myocardial infarction (AMI). The primary regulatory element of fibrinolytic activity is plasminogen activator inhibitor (PAI). There are no reports, however, on the serial changes of PAI activity after thrombolysis or coronary angioplasty in patients with AMI undergoing emergency coronary angiography. This study was designed to examine the difference in the change of fibrinolytic activity between patients with AMI who underwent thrombolytic therapy with recombinant tissue-plasminogen activator (rTPA) and those who underwent direct percutaneous coronary angioplasty (PTCA). We measured the serial changes of PAI activity and tissue plasminogen activator (TPA) antigen after rTPA therapy or direct PTCA. Twenty-two patients received emergency coronary angiography and were treated with rTPA intravenously. Twenty patients underwent direct PTCA. Plasma PAI activity levels were increased on admission and further increased within 24 hours in patients treated with rTPA and in those treated with direct PTCA. In the thrombolysis group, there were two peaks in plasma PAI activity levels (IU/ml) at 4 hours (27.0 +/- 2.9) and at 16 hours (25.6 +/- 2.5) after the initiation of rTPA infusion. However, in the direct PTCA group, there was one peak of PAI activity (IU/ml) at 16 hours (23.9 +/- 2.7) after the initiation of direct PTCA. In conclusion, the PAI activity has two peaks in the thrombolysis group and one peak in the direct PTCA group.

Down-regulation of bcl-xs gene expression in rat thymocytes by dexamethasone

In order to test a hypothesis that the expression of bcl-x gene promotes apoptosis by antagonizing the function of bcl-2 gene product, time course of the expression of bcl-x was investigated using the dexamethasone-treated rat thymocytes which were undergoing apoptosis. Unexpectedly, dexamethasone suppressed the expression of bcl-x in a dose- and time-dependent manner. Such decrease was detected even in the presence of cycloheximide, suggesting that the suppression is due to the genomic (primary) effect of dexamethasone. Since the expression of bcl-xL, as measured by a specific nucleotide probe, was not detected at a quantifiable level, the decrease was apparently attributed to that in bcl-xS. Our present observations propose a new role of the bcl-xS gene product, in which the bcl-x gene product may be necessary for survival of immature thymocytes rather than for their apoptosis.

Soluble P-selectin is released into the coronary circulation after coronary spasm

BACKGROUND

The glycoprotein P-selectin is an adhesion molecule involved in the property change of leukocytes at the initiation of the inflammatory process. The purpose of the present study was to determine whether acute myocardial ischemia induced by coronary spasm causes an acute inflammatory response in the coronary circulation.

METHODS AND RESULTS

We examined plasma soluble P-selectin levels in the coronary sinus and the aortic root simultaneously in 16 patients with coronary spastic angina before and after left coronary artery spasm induced by intracoronary injection of acetylcholine and in 15 patients with stable exertional angina before and after acute myocardial ischemia induced by rapid atrial pacing. Ten control patients with chest pain but normal coronary arteries and no coronary spasm also received intracoronary acetylcholine. Plasma soluble P-selectin levels were increased significantly in the coronary sinus (32.8 +/- 3.6 to 52.8 +/- 5.9 ng/mL, P < .001) and in the aortic root (34.6 +/- 3.7 to 41.9 +/- 4.4 ng/mL, P < .05) after the attacks in the coronary spastic angina group but remained unchanged in the stable exertional angina group after the attacks and in the control group after the administration of acetylcholine. Furthermore, the coronary sinus-arterial difference of soluble P-selectin increased significantly after the attacks in the coronary spastic angina group (-1.8 +/- 2.2 to 10.9 +/- 2.7 ng/mL, P < .001).

CONCLUSIONS

Our data indicate that soluble P-selectin is released into the coronary circulation after coronary artery spasm. We conclude that coronary artery spasm may induce the leukocyte adhesion in the coronary circulation and may lead to myocardial damage.

Identification of a new susceptibility locus for insulin-dependent diabetes mellitus by ancestral haplotype congenic mapping

The number and exact locations of the major histocompatibility complex (MHC)-linked diabetogenic genes (Idd-1) are unknown because of strong linkage disequilibrium within the MHC. By using a congenic NOD mouse strain that possesses a recombinant MHC from a diabetes-resistant sister strain, we have now shown that Idd-1 consists of at least two components, one in and one outside the class II A and E regions. A new susceptibility gene (Idd-16) was mapped to the < 11-centiMorgan segment of chromosome 17 adjacent to, but distinct from, previously known Idd-1 candidates, class II A, E, and Tap genes. The coding sequences and splicing donor and acceptor sequences of the Tnfa gene, a candidate gene for Idd-16, were identical in the NOD, CTS, and BALB/c alleles, ruling out amino acid changes in the TNF molecule as a determinant of insulin-dependent diabetes mellitus susceptibility. Our results not only map a new MHC-linked diabetogenic gene(s) but also suggest a new way to fine map disease susceptibility genes within a region where strong linkage disequilibrium exists.