Dissociation of DNA binding and in vitro transcriptional activities dependent on the C terminus of P53 proteins

Wild type p53 protein requires posttranslational modification within a carboxy-terminal negative regulatory domain to activate DNA binding and transcription. Binding of monoclonal antibody PAb421 to the carboxy-terminal domain reproduces this activation. In the absence of PAb421, we found that wild type p53 bound actively to a template containing two copies of the p21WAF1p53 binding site. However, in an in vitro transcription assay with partially purified basal transcription factors, p53 only partially activated transcription from the same binding site and required PAb421 for full activation. Oncogenic missense mutant p53 proteins (N239 to S239, G245 to S245, R273 to H273) bound the WAF1 doublet significantly and were activated further by PAb421. However, these mutants were inactive in the transcription assay, even with PAb421. These results indicate that sequence-specific binding and transcriptional activities of p53 can be dissociated through C-terminal interactions and suggest that conformational changes induced by the mutations alter p53 interactions with basal transcription factors.

Dietary effects of eicosapentaenoic and docosahexaenoic acid esters on lipid metabolism and immune parameters in Sprague-Dawley rats

Sprague-Dawley rats were fed eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) ethyl esters at the 2% level for 3 weeks to clarify their effects on immune functions. In the rats fed EPA or DHA, serum cholesterol, triglyceride, and phospholipid (PL) levels were significantly lower than those in the rats fed safflower oil. In PL fractions of serum, liver, lung, splenocytes, and peritoneal exudate cells (PEC), increases in linoleic and dihomo-gamma-linolenic acid contents and a decrease in arachidonic acid (AA) content were observed in the rats fed EPA or DHA. In addition, the EPA content increased in the rats fed EPA and DHA. In the rats fed EPA or DHA, a decrease of LTB4 productivity and an increase of LTBs productivity were observed in the PEC, in response to the treatment with 5 microM calcium ionophore A23187 for 20 min. The changes in leukotriene production were more marked in EPA-fed rats than in DHA-fed rats. These results suggest that dietary EPA affects lipid metabolism and leukotriene synthesis more strongly than DHA.

Idiopathic dilated cardiomyopathy in children: clinical profile and prognostic determinants

Idiopathic dilated cardiomyopathy is a severe disease with a high mortality rate in childhood. Its clinical evolution and prognosis are important for the selection of cardiac transplantation candidates. In order to characterize its evolution and identify prognostic factors, the clinical records of 41 children with the diagnosis of idiopathic dilated cardiomyopathy, admitted from January 1985 to December 1997, were reviewed. Survivors (Group I) and deceased (Group II) were separately analyzed, according to the following parameters: age, sex, race, clinical severity, electrocardiographic, echocardiographic and haemodynamic findings. Seven children were excluded from the study: six of them were lost to follow-up and one died from a surgical complication. Of the remaining 34 children, 20 were male (M) and 14 were female (F) (M/F: 1.4). Age range at diagnosis was 7 days to 14 years (median: 1.5 years), and follow-up time was from 18 days to 10.5 years (median: 2.5 years). Eleven (32.3%) children fully recovered, 13 (38.2%) survived with left ventricular dysfunction, and ten (29.4%) died, half of them within the first three months of follow-up. Mortality was 23.5% (8 out of 34 children) during the first year of follow-up and 29.4% (ten out of 34 children) at five years. Unfavorable prognosis was more frequently associated to: 1) clinical severity at the time of presentation; 2) lower mean left ventricular shortening fraction (10 +/- 7% in group II and 13 +/- 5% in group I); 3) occurrence of severe arrhythmia (40% in group II and 3.5% in group I). In this series a group of higher mortality risk was identified, based on some of the analyzed parameters, which should be considered as selection criteria for early heart transplantation.

Dietary effect of guar gum and its partially hydrolyzed product on the lipid metabolism and immune function of Sprague-Dawley rats

The dietary effect of the water-soluble dietary fibers (WSDF), guar gum, partially hydrolyzed guar gum (PHGG), glucomannan, highly methoxylated (HM) pectin, on the serum lipid level and immunoglobulin (Ig) production of Sprague-Dawley rats was compared with that of water-insoluble cellulose. Although serum total cholesterol and triglyceride levels were significantly lower in the rats fed with WSDF than in those fed with cellulose, a decrease in the level of phospholipids was only observed in the rats that had been fed on guar gum or glucomannan. In addition, all WSDF feeding enhanced IgA productivity in the spleen and mesenteric lymph node lymphocytes, although the increase in serum IgA level was only observed in the rats fed on WSDF, and not on PHGG. When mesenteric lymph node lymphocytes were cultured in the presence of various concentrations of guar gum or glucomannan, no significant increase in Ig production was apparent. These data suggest that WSDF indirectly enhanced the Ig production of lymphocytes, and that serum lipid reduction and IgA production-enhancing activities of WSDF were dependent on their molecular sizes.

Effect of dietary antioxidants on serum lipid contents and immunoglobulin productivity of lymphocytes in Sprague-Dawley rats

Sprague-Dawley rats were fed alpha-tocopherol, tocotrienol, or quercetin to examine their dietary effects on serum lipid contents and immunoglobulin productivity. In tocotrienol or quercetin groups, serum triglyceride was lower than in the none group. Moreover, in the alpha-tocopherol group, serum IgA level and IgA productivity of MLN lymphocytes were high, while in the tocotrienol group, IgM productivity of spleen lymphocytes and IgA, IgG, and IgM productivity of MLN lymphocytes were high. Thus, we suggested each antioxidant had different effects in rats.

Cerebral B-cell lymphoma following treatment for Tolosa-Hunt syndrome

We herein report a unique case of cerebral lymphoma which occurred after lymphocytic neuritis of cranial nerves causing Tolosa-Hunt syndrome and demonstrate the histological difference between these two diseases. A 70-year-old woman developed a sensory disturbance in the first and third divisions of the left trigeminal nerve and a left ocular movement disturbance five years before death. Although she was clinically diagnosed to have a schwannoma in the left cavernous sinus, a histologic examination verified a diffuse infiltration of T lymphocytes in the left trigeminal ganglion. Corticosteroid therapy was effective. Thereafter she demonstrated a disturbance of consciousness and dysphasia four years after surgery. A T1-weighted magnetic resonance image (MRI) disclosed high intensity lesions in both the basal ganglia and corpus callosum. She also showed progressive spastic paralysis. At autopsy a diagnosis of primary intracranial B-cell lymphoma was made. Although there was no invasion of the lymphoma cells into the left trigeminal nerves, a mild inflammatory infiltration of T cells still remained.

Interaction of the new histamine H2-receptor antagonist pibutidine hydrochloride with canine cloned H2-receptor expressed cells

The effect of a new histamine H2-receptor antagonist, pibutidine hydrochloride ((Z)-3-amino-4-{4-{4-[(piperidinomethyl)pyrid-2-yl]oxy} but-2-enylamino}cyclobut-3-ene-1,2-dione monohydrochloride, CAS 126463-66-9, IT-066 displaced the binding of [3H]tiotidine to cells transfected with the wild-type H2-receptor in a concentration-dependent manner. Compared with the 50% inhibitory concentration values (IC50) among five H2-receptor antagonists tested, the value of IT-066 was lowest. The inhibitory effect of IT-066 was enhanced by preincubation of IT-066 with the cells, and preincubation for 60 min increased potency about 2-fold. Famotidine also has such effects. When H2-receptor transfected cells were treated with IT-066 for 30 min, the inhibitory effect of IT-066 on the [3H]tiotidine binding still remained even after the cells were extensively washed. Scatchard plot analysis supported the non-competitive and irreversible action of IT-066. When the canine mutated H2-receptor-expressed cells were used, which have substituted amino acid of 190Alanine (Ala; position: 190th amino acid) for 190Threonine (Thr) in the fifth transmembrane domain, IT-066 also inhibited [3H]tiotidine binding to the cells concentration-dependently. However, in the case of the 190Ala mutated cells, the inhibitory effect of IT-066 attenuated with a decrease in maximal response after washing of the cells. These results show that IT-066 could tightly bind H2-receptor in a time-dependent manner and suggest the possibility that the irreversible inhibition of IT-066 is important in the interaction with 190Thr in the fifth transmembrane domain of H2-receptor.

Dietary effect of EPA-rich and DHA-rich fish oils on the immune function of Sprague-Dawley rats

The dietary effect of fish oils (FOs) rich in eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) on the immune function of Sprague-Dawley rats was compared with that of safflower oil. After 3 weeks of feeding at the 10% level of a dietary fat, the IgG and IgM production by splenocytes and IgG production by mesenteric lymph node (MLN) lymphocytes were significantly higher in the FO-fed rats, while no significant difference was found in IgA or IgE productivity by both the spleen and MLN lymphocytes. In the FO-fed rats, peritoneal exudate cells released a lower amount of LTB4, reflecting their lower arachidonic acid level, and a higher amount of LTB5, reflecting their higher EPA level in phospholipids. On these EPA-rich FO exerted a stronger effect than DHA-rich FO immune functions.

[Cardiovascular morbidity in children with human immunodeficiency virus infection]

Abnormalities of cardiovascular structure and function have been described among children with human immunodeficiency virus (HIV). In order to evaluate their occurrence and clinical predictors, 32 children infected with HIV, aged three months to 13 years (mean age = 3.11 +/- 3.51 years) were studied. Perinatal transmission was identified in 90% of the children. Twenty-two patients (pts) (69%) had symptoms, nine being moderately symptomatic and eight severely symptomatic. Fourteen pts had immunological disturbances and eight of them were severely immunosuppressed. Twenty-eight pts (88%) had HIV-1 infection and 6 recent Ebstein-Barr virus coinfection. Nineteen were on zidovudine and 14 on intravenous immunoglobulin treatment. Nineteen cardiovascular abnormalities were found in 15 pts (47%): 11 cases of pulmonary hypertension by echocardiographic criteria (eight of them had interstitial lung infiltrates seen on chest X-ray) and four cases of left ventricular dysfunction requiring anticongestive therapy. Other abnormalities were: patent ductus arteriosus, septal hypertrophy, mitral valve prolapse and pericardial effusion (one case each). Surface ECG displayed right ventricular hypertrophy in four pts, left ventricular hypertrophy in one patient and unspecific ST-T wave changes in two pts. Fourteen pts (44%) had sinus tachycardia with mean heart rate above the 95th percentile on 24-hour Holter monitoring.

CONCLUSIONS

Cardiovascular abnormalities are frequent among children with HIV-1 infection in late stages; pulmonary hypertension is the most frequently found cardiovascular anomaly and seems to be related to either chronic or recurrent respiratory disease; cardiological follow-up is recommended for HIV-infected children.

Antithrombotic effect of YM-75466 is separated from its effect on bleeding time and coagulation time

The antithrombotic effects of YM-75466 ([N-[4-[(1-acetimidoyl-4-piperidyl)oxy]phenyl]-N-[(7-amidino-2-nap hthyl)methyl]sulfamoyl]acetic acid monomethane sulfonate), a novel orally-active factor Xa inhibitor, and its effects on bleeding time and coagulation time were studied in rats and compared with those of warfarin. Both agents were orally administered. In the venous thrombosis model, YM-75466 and warfarin inhibited thrombus formation dose-dependently, with ID50 values of 3.3 and 0.56 mg/kg, respectively. Ex vivo study showed that both YM-75466 and warfarin prolonged prothrombin time dose-dependently, with doses, causing a two-fold prolongation of prothrombin time in the control group, of 89 and 0.38 mg/kg, respectively. In bleeding time studies, YM-75466 and warfarin prolonged bleeding time dose-dependently, with doses, causing a two-fold prolongation of bleeding time in the control group, of > 100 and 0.43 mg/kg, respectively. These results show that the antithrombotic effects of YM-75466 are markedly separate from its effects on bleeding time and coagulation time compared with warfarin.

Comparative studies on the antiplatelet effects of a humanized anti-platelet glycoprotein IIb/IIIa antibody (YM337) and ReoPro under flow conditions

Recent clinical studies have shown that the interruption of platelet function appears to be effective for treatment of coronary occlusive diseases. For this purpose, a Fab fragment of humanized anti-platelet glycoprotein (GP) IIb/IIIa monoclonal antibody (YM 337) that exhibited an in vivo antithrombotic effect without prolongation of bleeding time in monkeys was previously characterized. In this study, the effect of YM 337 under physiological flow conditions with high or low shear rate was evaluated. The antiplatelet effects of YM 337 under varying wall shear rates were examined with the whole blood flow system. This technique allows real time visualization of the formation of fluorescence-labeled platelet thrombi on a collagen surface in a parallel plate flow chamber mounted on an epifluorescence microscope. The process of thrombus growth was also recorded in video tape and subjected to computer-assisted image analysis. We found that YM 337 displayed a high shear-preferential antiplatelet effect, while ReoPro, a control anti-GP IIb/IIIa antibody, did not show such shear dependency. The present findings therefore suggest that YM 337 might be a useful antiplatelet agent which can block pathological thrombotic events occurring under high shear, such as in coronary occlusive diseases.

[Prenatal cardiology. Suspicion to confirmation]

The mortality rate is high and prognosis is worse among new-borns with prenatal diagnosis of heart malformation, mainly due to factors such as its association with other malformations, and a range of more severe diseases probably resulting from the predominance of the obstetric use of the four chamber view. In this study we retrospectively assessed the range of cardiopathies diagnosed by foetal echocardiography and their evolution, compared with previous years. From January 1994 to December 1995, 1173 foetal echocardiograms were performed at a gestation age of 24 weeks. Sixty-one foetuses (5.2%) had cardiac anomalies, structural in 56 and arrhythmia in 5. The risks and indications were maternal in 37%, foetal in 31%, familial in 17% and environmental in 15%. Three were false negatives (VSD:2; truncus arteriosus: 1). Five died in utero, and 18 were assessed after birth with a mean gestational age of 37 weeks and birth weight of 3 Kg, a caesarean section was performed in 9. All but one were born in central hospitals. Six children were operated on. Two children died, one after surgery. Compared with the four previous years of activity, indication due to foetal risk rose from 6 to 31%, the number of cases diagnosed with heart disease increased from 14 to 30 per year, and the mortality decreased from 59 to 11%. Despite this, we still observe that the vast majority of new-borns who are hospitalised due to a severe heart disease had no prenatal diagnosis, indicating the need to continue our educational policy in this field.

Wild-type and mutant forms of p53 activate human topoisomerase I: a possible mechanism for gain of function in mutants

p53-interacting proteins from mouse epidermal cells and human myelogenous leukemia cells were isolated by affinity chromatography using glutathione S-transferase (GST)-p53 fusion proteins. One of these proteins was topoisomerase I, whose interaction with p53 was recently reported. A carboxyl-terminal fragment containing the last 92 amino acids of p53 (GST-299-390) was sufficient for binding to topoisomerase I. Nanomolar concentrations of either GST-p53 or GST-299-390 enhanced the catalytic activity of purified human topoisomerase I. Purified wild-type human p53 and point mutants Ser-239, Ser-245, and His-273 were equivalent in their enhancement of human topoisomerase I activity. Because topoisomerase I is thought to promote genetic recombination, competence to enhance topoisomerase I catalytic activity coupled with a deficiency in transcriptional activity may be a mechanism for gain of function in mutant p53 proteins.

Evaluation of a GPIIb/IIIa antagonist YM337 in a primate model of middle cerebral artery thrombosis

We compared the antithrombotic effect of anti-GPIIb/IIIa antibody Fab fragment YM337 with that of a thromboxane A2 synthetase inhibitor, sodium ozagrel. With the monkeys under halothane anesthesia, the right middle cerebral artery was observed via a transorbital approach without cutting the dura mater. Photoillumination (wavelength 540 nm) was applied to the middle cerebral artery, and then rose bengal (20 mg kg(-1)) was administered intravenously. The experimental drugs were intravenously injected 15 min before rose bengal injection and followed by continuous infusion for 3 h after dye injection. The thrombotic occlusion induced by this photochemical reaction in monkey middle cerebral artery was reproducible. YM337 significantly prolonged the time to first occlusion and the total time of arterial patency during the 3-h observation period after dye injection. In contrast, sodium ozagrel had no significant effect. YM337 but not sodium ozagrel significantly inhibited ex vivo ADP-induced platelet aggregation. However, while sodium ozagrel significantly inhibited the thromboxane B2 generation accompanying arachidonic acid-induced platelet aggregation, YM337 had no effect on this variable. Neurological deficit in the YM337-treated animals was significantly milder than that in the control group. The area of infarct in the YM337 treatment animals was smaller than that in the control group. The novel selective GPIIb/IIIa antagonist YM337 was effective in ameliorating the decrease in patency of the middle cerebral artery and reducing the area of cerebral infarction in monkeys.

Enhancement of tissue-type plasminogen activator-induced thrombolysis and prevention of reocclusion by combination with a humanized anti-glycoprotein IIb/IIIa monoclonal antibody, YM337, in a rhesus monkey model of coronary thrombosis

We examined the effect of a humanized anti-glycoprotein IIb/IIIa monoclonal antibody, YM337, on thrombolysis with tissue-type plasminogen activator in a copper coil-induced coronary thrombosis model in rhesus monkeys. Fifty minutes after the formation of an occlusive thrombus, a test drug was administered by either i.v. bolus injection followed by continuous infusion (YM337, 0.25 mg/kg + 1.5 microg/kg/min) or i.v. bolus injection (aspirin, 17 mg/kg). Sixty minutes after induction of the occlusive thrombus, thrombolysis was initiated with tPA at a total dose of 0.5 mg/kg intravenously administered over 60 min, with 10% given as an initial bolus. The median time to reperfusion was significantly shortened by YM337 [saline, 60 min (n = 5); aspirin, 45 min (n = 5); YM337, 30 min (n = 5)]. The incidence of reocclusion was significantly decreased by YM337 (saline, 4/4; aspirin, 5/5; YM337, 1/5), and the median time to reocclusion was significantly prolonged by YM337 [saline, 30 min (n = 4); aspirin, 30 min (n = 5); YM337, 180 min (n = 5)]. YM337 significantly reduced the thrombus protein content at the end of experiment. ADP-induced platelet aggregation was completely inhibited by YM337. These results suggest that YM337 may be of clinical value as an adjunctive agent in thrombolytic therapy for patients with acute myocardial infarction.

A novel D-amino-acid-containing peptide isolated from Aplysia heart

A novel cardio-excitatory peptide was purified from the hearts of Aplysia kurodai. The peptide was a tripeptide containing a D-amino acid residue in the second position, Asn-D-Trp-Phe-NH2 (NdWFamide). NdWFamide increased the amplitude of contractions of the perfused Aplysia heart with little effect on beating frequency, showing a threshold of approximately 10(-11) M. The peptide also potentiated spontaneous contractions of the anterior aorta. The synthetic peptide having L-Trp instead of D-Trp was about 1,000 times less potent than the native one. NdWFamide seems to play an important role in regulation of cardiac activity in Aplysia.

Comparison of the antiplatelet effect of YM337 and abciximab in rhesus monkeys

We directly compared the effects of YM337, the Fab fragment of the humanized monoclonal antibody C4G1, on platelet aggregation and template bleeding time with those of abciximab, the Fab fragment of the human/murine chimeric monoclonal antibody 7E3, in rhesus monkeys. The duration of inhibition of platelet aggregation by abciximab after i.v. bolus injection was much longer than that by YM337. Although YM337 significantly prolonged template bleeding time at 5 min after i.v. bolus injection, this action recovered within 1 h after injection. In contrast, although abciximab also prolonged template bleeding time, the duration of this effect was sustained. In a dose-escalating continuous infusion study, we evaluated the relationship between inhibition of platelet aggregation and prolongation of template bleeding time. Platelet aggregation was inhibited by over 80% by both agents at 3 microg/kg per min, and template bleeding time was prolonged to about 30 min at 30 microg/kg per min for YM337 and 10 microg/kg per min for abciximab. Interestingly, plasma concentrations between inhibition of platelet aggregation and prolongation of template bleeding time did not overlap with YM337, but did overlap with abciximab. These results suggest that YM337 allows easier control of antiplatelet activity with less effect on bleeding time than abciximab, and has a wider therapeutic window than abciximab.

Evaluation of the disintegrin, triflavin, in a rat middle cerebral artery thrombosis model

Platelet aggregation plays a important role in the thrombotic cerebral infarction. The final common mechanism in the formation of a platelet aggregate is the linking of adjacent platelets by fibrinogen binding to the platelet integrin alpha 11b beta 3. In this study, we evaluated the effect of the disintegrin, triflavin, in a rat middle cerebral artery thrombosis model. Thrombus at the left middle cerebral artery in rat was induced by photochemical reaction between rose bengal and green light, which caused endothelial injury at the site of irradiation. We measured the time to occlusive thrombus formation and the size of ischaemic cerebral damage. Triflavin dose dependently prolonged the time to occlusive thrombus formation in this model. Triflavin also reduced the size of ischaemic cerebral damage on examination at 24 h after photochemical reaction. Triflavin dose dependently inhibited ADP- and collagen-induced platelet aggregation and platelet retention in the collagen-coated beads method ex vivo. These effects were thought to result from the blockade of platelet integrin alpha IIb beta 3. Blockade of platelet integrin alpha IIb beta 3 may be useful in the prevention of cerebral arterial thrombosis.

Effect of vegetable extracts on immunoglobulin production by mesenteric lymph node lymphocytes of Sprague-Dawley rats

To clarify the immunoglobulin production-regulating activity of vegetable extracts, mesenteric lymph node lymphocytes of Sprague-Dawley rats were cultured in the presence of 25 different vegetable extracts. The immunoglobulin content in the culture medium determined by ELISA indicated that the lily family (Liliaceae) vegetables most strongly enhanced the production of IgA and IgG, whereas they suppressed IgE production.