Studies on the castability of Co-Cr alloy for cast plates. Part 2: Effect of form of sprue attachment to the wax pattern

Co-Cr alloy is used more frequently than Ni-Cr alloy as a non-precious alloy for cast plates in Japan. However, since the melting point of Co-Cr alloy is very high, about 1300 degrees C, and since it oxidizes easily, a vacuum-pressure casting machine capable of melting this alloy in a reducing atmosphere has recently been developed. Using this vacuum-pressure casting machine, the authors studied the effects on the castability of Co-Cr alloy due to the form of sprue attachment to the wax pattern. The results clarified that in the vacuum-pressure casting method, the form of sprue attachment to the wax pattern has a significant effect (p less than 0.01) on the castability of Co-Cr alloy.

Effects of MCI-154, a novel cardiotonic agent, on mean circulatory filling pressure in anesthetized dogs

The effects of MCI-154, a novel cardiotonic agent, on mean circulatory filling pressure (an index of total body venous tone), total peripheral resistance and the heart were examined in anesthetized dogs. The bolus injection of MCI-154 (10-100 micrograms/kg i.v.) caused a dose-dependent decrease in mean circulatory filling pressure and resistance to venous return. MCI-154 also decreased the mean blood pressure and total peripheral resistance, and increased cardiac output and heart rate. Right atrial pressure was reduced only by the lowest dose (10 micrograms/kg i.v.) of MCI-154. These hemodynamic effects of MCI-154, except those on mean circulatory pressure and resistance to venous return, reached a maximum with 30 micrograms/kg of the drug. Nitroglycerin (50 micrograms/kg i.v.), a venodilator, decreased mean circulatory filling pressure, resistance to venous return, mean blood pressure and total peripheral resistance, and increased heart rate. However, unlike MCI-154, nitroglycerin did not alter cardiac output and right atrial pressure. These results suggest that the venodilator effect of MCI-154, as well as the positive inotropic and vasodilator effects, could potentially benefit patients with congestive heart failure.

[A case of major dehiscence of a prosthetic aortic valve]

A case, 48-year-old man, was presented of dehiscence of an aortic Björk-Shiley prosthesis, which was diagnosed by pendular movement of prosthetic mount in cineangiographic finding. Emergent operation of Re-AVR was performed successfully. Valve dehiscence should be confirmed by cineangiographic examination, in case of progressive congestive heart failure combined with traumatic hemolytic anemia and high grade fever suggestive of prosthetic valve endocarditis.

[Pulmonary Tuberculosis in foreigners]

We studied the background and social problems of pulmonary tuberculosis in foreigners which we recently encountered at the National Chiba- Higashi Hospital and the Chiba Anti-tuberculosis Association. 1) The number of foreigners with pulmonary tuberculosis has been increasing year by year, one in 1983, none in 1984 and 1985, one in 1986, two in 1987 and four in 1988. 2) Most of these patients had been already infected or had some symptoms before their arrival to Japan. 3) Their background includes some serious social problems such as troubles in daily life coming from linguistic and cultural differences and economic difficulties, legal problems such as illegality of their stay in Japan, etc. 4) Most of the above cases could not be treated sufficiently because they are foreigners or because of their illegal stay.

[The effects of intravenous infused magnesium on hemodynamics and renal water-sodium metabolism in patients with essential hypertension]

Mean arterial pressure (MAP), heart rate (HR), urine volume (UV), urinary excretion of sodium (UNaV), endogenous creatinine clearance (Ccr), fractional excretion of sodium (FENa) were measured before and after intravenous infusion of 10% magnesium sulfate (an initial dose: Mg 13.5 mg/m2.BSA/15 min; a maintenance dose: Mg 2.7 mg/m2.BSA/105 min) in 6 normotensive subjects (NT) and 12 mild-to-moderate essential hypertensives (EHT). Following magnesium infusion, serum magnesium concentration (s-Mg) increased and reached the level of about 1.8 times basal value. Significant increases of UV, UNaV and FENa in both NT and EHT, and a similar tendency of Ccr in EHT were observed, while no significant change in MAP nor HR was found in the two groups. The changes in UNaV (delta UNaV) were positively correlated with those in FENa (delta FENa) and a similar tendency was shown between delta UNaV and change in Ccr (delta Ccr) in all subjects. While there was no significant percentage change of s-Mg (% delta s-Mg) nor of Ccr (% delta Ccr), those of UNaV (% delta UNaV) and FENa (% delta FENa) were significantly greater in EHT. It is concluded from these findings that magnesium infusion produces diuresis and the natriuresis which might result from suppression of renal tubular reabsorption of sodium, without any change in systemic hemodynamics in NT and EHT. The pronounced natriuretic response to magnesium in EHT might contribute to the hypotensive mechanism of magnesium loading in EHT.

[Long-term results of intra-arterial infusion therapy using cis-DDP (CDDP) in thoracic esophageal cancer]

The effects of intra arterial infusion therapy using CDDP for patients with thoracic esophageal cancer were investigated. From June 1984 to December 1988, 25 of 146 resected patients with thoracic esophageal cancer underwent preoperative therapy in our institute. All of these patients it was suspected preoperatively that their chief lesion had invaded to the aorta, trachea or main bronchi. Preoperative radio-chemotherapy with intra arterial infusion therapy was given to 10 of 25 patients (A group), and without intra arterial infusion therapy to 15 of 25 patients (B group). CDDP 75 mg was infused into the proper esophageal artery. In A group, 7 of 10 (70%) showed moderately or marked effects in histologic study, although in B group, only 4 of 15 (27%) did so. As for long-term results, the 2-year survival rates were 50% in A group and 13% in B group (Kaplan-Meier method. Preoperative intra arterial infusion therapy using CDDP with radio-chemotherapy showed markedly better effects in histologic study and survival rates than preoperative radio-chemotherapy without intra arterial infusion therapy. We consider that this therapy is very useful for controlling the local lesion in advanced esophageal cancer.

[Distribution of pulsed intra arterial infusion chemotherapy in hepatic carcinomas]

Evaluation of "Gianturco-Wallace chemotherapy pulser," which was developed to produce a more homogeneous drug distribution of the tumors in intra-arterial infusion chemotherapy, was assessed by comparative study of pulsed and nonpulsed arterial radionuclide infusion using Tc-99m pertechnetate for 18 cases of hepatic carcinomas (11 cases of hepatocellular carcinomas and 7 cases of metastatic hepatic carcinomas). Tc-99m pertechnetate, 740 MBq (20 mCi) diluted with saline (30 mL) was infused with or without pulse through the catheter into the hepatic artery at a rate of 1mL per minute. The intrahepatic dynamic radionuclide distribution was analyzed by the time activity curves of ROIs in the tumor and nontumor areas. Pulsed infusion interrupted laminar flow and produced more homogeneous radionuclide distribution in the liver, and combination of pulsed and nonpulsed infusion also produced better radionuclide distribution in the areas of the tumors. This method using Tc-99m pertechnetate was very useful as a simulation to determine the dynamic drug distribution of the tumor and non-tumor region in intraarterial infusion methods.

Potentiation of para-hydroxyamphetamine-induced head-twitch response by inhibition of monoamine oxidase type A in the brain

After pretreatment with either clorgyline, a monoamine oxidase (MAO)-A-selective inhibitor, or pargyline, an MAO-B-selective inhibitor with less selectivity than l-deprenyl, i.c.v. administration of para-hydroxyamphetamine (p-OHA) significantly increased both the frequency and total number of head-twitches in mice. A typical MAO-B-selective inhibitor, l-deprenyl, however, did not change the total count of the p-OHA-induced head-twitch response (HTR). These effects were also found with fixed doses of the selective MAO inhibitors when p-OHA was varied. Administration of clorgyline (1 mg/kg) or pargyline (5 mg/kg) almost inhibited completely MAO-A in the mouse forebrain, and pargyline also almost inhibited completely MAO-B. l-Deprenyl, in contrast, almost inhibited completely MAO-B without affecting MAO-A activity. Systemic administration of l-5-hydroxytryptophan also induced HTR and the total number of twitches was enhanced by clorgyline, but not by pargyline or l-deprenyl. Chlorimipramine or cocaine significantly reduced p-OHA-induced HTR, suggesting an intraneuronal site of action. Together with the presence of considerable MAO-A in 5-hydroxytryptamine (5-HT) neurons of various animal species, and possible accumulation and subsequent monoamine-releasing properties of p-OHA, the present results indicate that p-OHA might induce the HTR by interaction with intraneuronally increased 5-HT. This mechanism probably results in 5-HT release onto the postsynaptic 5-HT2 receptors. Taken together, different roles of MAO-B in "the hyperactivity syndrome" and the HTR are discussed.

[The role of the Na, K-ATPase inhibitor in renal sodium handling in patients with essential hypertension]

The present study aimed to elucidate the role of Na, K-ATPase inhibitor in renal sodium metabolism in essential hypertension. Mean arterial pressure (MAP), heart rate(HR), urine volume (UV), urinary excretion of sodium (UNaV), endogenous creatinine clearance (Ccr), fractional excretion of sodium (FENa), plasma renin activity(PRA) plasma aldosterone concentration(PAC), plasma noradrenaline concentration (PNA) and urinary excretion of noradrenaline(UNA) were measured before and after intravenous injection of ouabain (0.1 mg/m2.BSA) in 12 normotensive(NT) and 22 mild-to-moderate essential hypertensive subjects(EHT). Following ouabain injection, UV, UNaV FENa significantly increased, but PRA decreased, in both NT and EHT. MAP, HR, Ccr, PNA, and UNA did not change significantly in either group. On the other hand, a significant decrease in PAC was observed in NT, but not in EHT. The changes of UNaV and FENa were significantly attenuated in EHT as compared to NT. No significant difference in change of MAP, HR, UV, Ccr, PNA, UNA, or PRA was demonstrated between NT and EHT. A significantly positive correlation was found between delta UNaV and delta FENa in both NT and EHT, while no significant correlation was observed between delta UNaV and delta MAP, delta UV, delta Ccr, delta PRA, delta PAC, delta PNA and delta UNA in either group. These results suggest that 1) Na, K-ATPase inhibitor clearly augments natriuresis by suppression of sodium reabsorption in renal tubules, 2) since this augmentation was attenuated, there is an elevation of endogenous Na, K-ATPase inhibitor(s) should be considered in EHT, and 3) an increase of the inhibitor might participate to the hypertensive mechanism in EHT.

[Studies of diagnosis of rectal cancer using MRI, CT and intrarectal ultrasonography]

Examination using MRI, CT and Intrarectal Ultrasonography (US) were performed in 186 patients with primary rectal cancer and 127 postoperative cases, in order to diagnose the depth of invasion, lymph node metastases and local recurrence. In the diagnosis of depth of invasion, intrarectal US was superior to MRI and CT for detailed diagnosis, and MRI was the best examination modality for detecting infiltration of other organs. Also, these were available for the diagnosis of lymph node metastases, and intrarectal US was superior to MRI and CT for detecting small lymph nodes. In the detection of local recurrence, MRI, CT guided biopsy and intrarectal US were useful, especially MRI was the best examination for the decision of re-resection.

Determination and regulation in the pigment cell lineage of the ascidian embryo

The brain of the ascidian larva comprises two pigment cells, termed the ocellus melanocyte and the otolith melanocyte. Cell lineage analysis has shown that the two bilateral pigment lineage cells (a-line blastomeres) in the animal hemisphere give rise to these melanocytes in a complementary manner. The results of the present investigation suggest that the specification of the fate of pigment cells proceeds in two distinct steps. First, the determination of pigment lineage cells requires an inductive interaction from the vegetal blastomeres of the A-line. Cell dissociation experiments demonstrated that the inductive interaction is completed by the midgastrula stage. However, the two bilaterally positioned cells destined to become the pigment cells in the first step are still equipotent at this stage in that they can give rise to either the ocellus or otolith. Thus, they constitute what is termed an "equivalence group." In the second step, the individual fates of the two cells that compose the equivalence group are determined. Namely, one cell develops into an ocellus and the other cell develops into an otolith. Photoablation of one of the pigment precursor cells at various stages indicated that the second step of determination occurs at the midtailbud stage. It is suggested that the cue to choose one of the alternative developmental pathways may be positional information that exists along the anteroposterior axis. The second step of determination is thought to be mediated by a hierarchical interaction. In the absence of this interaction, melanocyte specification proceeds along the dominant pathway that results in the differentiation of an ocellus.

[Clinical evaluation of CA-50 in cases with colorectal cancer]

Serum CA-50 has been evaluated in 67 healthy donors and in 46 patients with a colorectal cancer by an enzyme immunoassay (EIA Kit, Mitsui pharmaceuticals, Inc.). The mean value of the healthy donors (n = 67) was 10.6 +/- 6.1 U/ml and for patients with a colorectal cancer 31.7 +/- 55.2 U/ml. Both in healthy donors and in patients, the mean value was found to be higher in females than males. The overall sensitivity in the colorectal cancer patients was 26.1 percent, the percentages for those in stage I, 20, II, 9.1, III, 40, IV, 20, and V, 50% respectively. In a correlation between serum CA-50 and CA 19-9, the correlation coefficient was 0.82 (p less than 0.01), and in between CA-50 and CEA, 0.51 (p less than 0.01). Thus a combination assay among CA-50, CA 19-9, and CEA has proved to be of significant value in cases of a colorectal cancer.

Reversal effect of thyroxine on altered vascular reactivity in diabetic rats

The influence of thyroxine treatment on the altered reactivity of the isolated perfused mesenteric vasculature from streptozocin-induced diabetic rats was examined and compared with that of insulin. After 8 weeks of diabetes, the time when the decreased response to isoproterenol appeared, treatment with thyroxine reversed this decreased response to control levels. However, thyroxine replacement did not reverse the decreased responsiveness to norepinephrine, 5-hydroxytryptamine, acetylcholine, and isoproterenol after 12 weeks of diabetes. On the other hand, insulin replacement improved the vascular responsiveness to these agonists at 8 and 12 weeks. Insulin treatment also reversed the attenuated response to nerve stimulation found in diabetic rats, whereas thyroxine treatment did not improve it. Insulin treatment reversed the decreased plasma thyroid hormone levels similarly as thyroxine treatment. These results suggest that thyroid hormone deficiency is likely to be involved partly in the altered reactivity of the rat mesenteric vasculature at the early period of diabetes. On the other hand, adrenergic neuropathy is not induced by hypothyroidism.

In vitro characterization of the effects of MCI-154, a novel cardiotonic agent, on cardiac tissues

In vitro cardiac effects of a cardiotonic drug, MCI-154, for which the main action mechanism was proposed to be the enhancement of Ca2+ sensitivity of cardiac contractile proteins, were investigated. MCI-154 (3 x 10(-8)-3 x 10(-4) M) increased the developed tension in isolated ventricular muscles from cats, dogs, guinea pigs and rats and increased that of isolated left atrial muscles of guinea pigs and rats. However, species differences were observed in the responses to MCI-154. The positive inotropic potency of MCI-154 was stronger than those of amrinone and milrinone. In the isolated right atria from guinea pigs and rats, properties of the chronotropic effect of MCI-154 were different from those of amrinone and milrinone. The positive inotropic action of MCI-154 was not affected by phentolamine, propranolol, cimetidine and tetrodotoxin. MCI-154 did not inhibit cardiac Na+,K+-ATPase. MCI-154 moderately stimulated Ca2+-uptake of isolated cardiac sarcoplasmic reticulum (SR), but induced no release of Ca2+ from the SR. These results support the view that the main mechanism for the action of MCI-154 is the enhancement of Ca2+ sensitivity of cardiac contractile proteins.

[Emergent surgical management of aortic dissecting aneurysm, type A Stanford, complicated with acute cardiac tamponade; report of a case]

A 52-year-old woman, who had been treated medically for 31 days with the diagnosis of type A aortic dissection, suddenly fell in shock because of acute cardiac tamponade. Emergent operation was performed two hours after the onset of shock. Entry and perforation were located in the ascending aorta. Ascending aorta was opened without cross-clamping under profound hypothermic low flow perfusion through femoral artery, and intraluminal grafting with a double ringed graft was completed. Combined technique of open distal anastomosis and ringed graft is useful in such an emergent case as cardiac tamponade of aortic dissection.

The effect of hepatic artery ligation for irresectable cavernous hemangioma of the liver

During the past 19 years, 52 cases of hepatic cavernous hemangioma have been treated at our institution. Thirty patients underwent hepatic resection. In six patients, the extensive tumor mass invaded multiple segments or both lobes of the liver and complete resection was deemed hazardous. Therefore, hepatic artery ligation was carried out. In all six cases the hemangioma occupied more than two segments. Right hepatic artery ligation was done in five patients and left hepatic artery ligation in one. All are doing well without complication. The longest follow-up is 19 years and the shortest 2 years and 2 months following operation. Four patients have been followed for more than 4 years and in all patients there are no residual complaints. Computerized tomography (CT) revealed the reduction of the tumor size after arterial ligation. One patient suffered from cholecystolithiasis 9 years after hepatic artery ligation, and at the time of cholecystectomy, a biopsy and microscopic examination of the lesion revealed evidence of fibrotic degeneration of the hemangioma. These findings indicate the effectiveness of hepatic artery ligation for treatment of hepatic cavernous hemangioma that are judged hazardous to resect.

[Clinical evaluation of a combination assay of CEA, CA-19-9 and TPA in patients with colorectal cancer]

The effectiveness of serum CEA (56 cases), CA-19-9 (53 cases) and TPA (48 cases) in patients with colorectal cancer has been evaluated. The preoperative sensitivity and specificity of CEA and CA 19-9 were found to be almost the same in level but the level of TPA was low. In 20 cases recurrent, the sensitivity of the marker was 66.7% in the liver, 60% in the lung, and 66.7% in the local recurrence of primary foci. In these recurrent cases, serum CEA in initially elevated to 65%, CA 19-9 to 25%, and TPA to only 10%. In diagnostic rate imaging or in our clinical findings, however, the frequency was almost the same as tumor markers.

Changes in vascular reactivity in experimental diabetic rats: comparison with hypothyroid rats

The responsiveness to vasoactive agents in the perfused mesenteric vascular bed of streptozocin-induced diabetic rats was examined and compared with that of propylthiouracil-induced hypothyroid rats. Diabetic rats at 4 and 8 weeks after the induction of diabetes showed a significant decrease in isoproterenol-induced vasodilatation. In addition, the contractile responses to norepinephrine and 5-hydroxytryptamine and the vasodilative response to acetylcholine were significantly decreased in 12-week-diabetic rats. The contractile response to nerve stimulation was markedly decreased at 8 and 12 weeks. On the other hand, hypothyroid rats showed a decreased response to isoproterenol, but they did not show any change in the response to nerve stimulation. A decrease in plasma thyroid hormone levels in diabetic rats at any time period was similar in extent to that in hypothyroid rats. The data indicate that the progressive changes in vascular reactivity in diabetic rats may be divided into two stages. In the early stage, the altered reactivity of vasculature is likely to be mediated by hypothyroidism, whereas in the later stage, it is induced by other factors, e.g. hyperglycemia and hypoinsulinemia. Adrenergic neuropathy is not caused by hypothyroidism.

[Effects of RU38486, an antiprogesterone agent, on endometrium, fertilized ovum and serum sex steroid levels in rats]

Effects of antiprogesterone RU38486 were studied in rats. The synthetic compound effectively (100%) inhibited implantation when administered on day 2 as well as on day 4 postconception (2.5mg/kg, in glycerol). This treatment, however, did not alter circulating estradiol and progesterone levels. Fertilized ovum yielded on day 4 from the uterine cavity showed normal morphology including adequate progress in cell division. A light microscopic study of the endometrium showed decreased cytoplasmic vacuole formation but estrogenic effects were apparently preserved. These data suggest that administration of RU38486 immediately after conception could successfully prevent implantation without altering early luteotropic functions in rats. Also the high dose of the compound was found to have no significant toxic effects on fertilized ovum, indicating that the anticonceptional action of RU38486 mainly functions at the uterine endometrial level.

Acute effects of a parkinsonism-inducing neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on mouse body temperature

The parkinsonism-inducing neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) given in single systemic doses (i.p.) to mice produced marked hyperthermia, and subsequent long-lasting hypothermia. Administration of MPTP or its oxidized product, 1-methyl-4-phenylpyridinium ion, MPP+, via i.c.v. resulted in only hypothermia. In contrast, i.p. MPP+ administration resulted in only hyperthermia. The MPTP-induced hyperthermia (i.p.) was blocked by quaternary derivatives of anti-cholinergic agents, atropine and scopolamine, but not by the tertiary-derivative of atropine. Duration of this hyperthermic effect was potentiated by neostigmine. Pretreatment with 1-deprenyl did not prevent hypothermia, but nomifensine partially or clorgyline completely prevented the effect without preventing MPTP-induced hyperthermia. The thermic effects by MPTP, unlike its neurotoxicity for the nigrostriatal DA system, may not require metabolism to MPP+. These results indicate that peripheral cholinergic functions are responsible for the MPTP-induced hyperthermia, whereas its hypothermic effect may be centrally mediated via dysregulation of the various neuron systems.

Central hypothermic effects of some analogues of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 1-methyl-4-phenylpyridinium ion (MPP+)

Effects of some MPTP or MPP+ analogues on mouse body temperature were studied. Of the analogues tested, 4-phenylpyridine (PPY) and 4-phenyl-1,2,3,6-tetrahydropyridine (PTP) given in single i.p. doses to mice caused marked hypothermia. Intracerebroventricular (i.c.v.) injection of PPY or PTP caused similar hypothermia. Pretreatment with clorgyline or (-)-deprenyl greatly prevented hypothermia induced by i.c.v. PPY, but hypothermia by i.c.v. PTP was prevented only by (-)-deprenyl. These results indicate that, in order to cause central hypothermia, PTP does not seem to require metabolism to PPY and both analogues per se may cause hypothermia.

Antibody to platelet activating factor (1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine; PAF)

Specific antibodies to platelet activating factor (PAF) were prepared by immunizing rabbits with a hapten-bovine serum albumin (BSA) conjugate. As the hapten we used the synthetic PAF derivative which is resistant against enzymatic inactivation by plasma or tissues and which can bind to BSA through covalent bonding. Antibody activity was determined by an enzyme-linked immunosorbent assay (ELISA). Anti-PAF IgG reacted strongly with PAF. By means of the ELISA inhibition assay, we found that the antibody did not cross-react with phosphocholine, glycerophosphocholine, dilaurylglycerophosphocholine or PAF analogues which have ethanolamine-type polar head groups instead of choline group.

Monoclonal antibodies against components of the myoplasm of eggs of the ascidian Ciona intestinalis partially block the development of muscle-specific acetylcholinesterase

The myoplasm of Ciona intestinalis eggs, believed to contain cytoplasmic determinants responsible for muscle cell differentiation in ascidian embryos, emits weak pale-blue autonomous fluorescence. Utilizing this feature as a marker, the cytoplasm was isolated according to the method described by Jeffery (1985b). Electron microscopy showed that the isolated cytoplasm contained mitochondria, pigment granules, yolk particles and fine granular materials; these are ultrastructural components of the myoplasm of the intact egg. Monoclonal antibodies were prepared against the isolated cytoplasm. Twelve monoclonal antibodies, identified by indirect immunofluorescence, stained the myoplasmic region. When unfertilized eggs were centrifuged, stratifying their mitochondria and some other cytoplasmic components, components identified by several antibodies, for example IIG6B2, remained at the peripheral cytoplasm of the egg. Other antibodies recognized components stratified as the mitochondrial layer. Four representative antibodies were microinjected into fertilized eggs in order to examine their inhibitory effects on the muscle differentiation; the IIG6B2 antibody blocked the development of muscle-specific acetylcholinesterase in more than 80% of the embryos tested.

Expression of epidermis-specific antigens during embryogenesis of the ascidian, Halocynthia roretzi

We have produced two monoclonal antibodies (Epi-1 and Epi-2) which specifically recognize epidermal cells and their derivative, the larval tunic, of developing embryos of the ascidian Halocynthia roretzi. The antigens, examined by indirect immunofluorescence staining, first appear at the early tailbud stage and are present until at least the swimming larval stage. There were distinct and separate puromycin and actinomycin D sensitivity periods for each antigen. Aphidicolin, a specific inhibitor of DNA synthesis, prevented the appearance of each antigen when embryos were exposed to the drug continuously from cleavage stages. These results suggest that the antigens are synthesized during embryogenesis by developing epidermal cells and that several rounds of DNA replication are required for the antigen expression. Early cleavage stage embryos, including fertilized but unsegmented eggs, in which cytokinesis had been blocked with cytochalasin B expressed the antigens, and blastomeres exhibiting the antigens were always of the epidermis lineage. In partial embryos produced by four separated blastomere pairs of the 8-cell embryos, the expression of antigens was seen only in those developed from the animal blastomere pairs, which are progenitors of epidermal cells. These observations indicate that differentiation of epidermal cells in ascidian embryos takes place in a typical "mosaic" fashion.

Cardiovascular pharmacology of 6-[4-(4'-pyridyl)aminophenyl]-4,5-dihydro-3(2H)-pyridazinone hydrochloride, a novel and potent cardiotonic agent with vasodilator properties

The cardiovascular profile of 6-[4-(4'-pyridyl)aminophenyl]-4,5-dihydro-3(2H)-pyridazinone hydrochloride (MCI-154), a novel cardiotonic agent structurally different from cardiac glycosides and beta-adrenoceptor agonists, was investigated in vivo. In anesthetized, open-chest dogs, MCI-154 (0.3-100 micrograms/kg i.v., bolus injection) produced dose-dependent increases in dP/dtmax and cardiac output, and decreases in arterial blood pressure and total peripheral resistance with a relatively small increase in heart rate. The positive inotropic effect of MCI-154 was more potent than those of amrinone and milrinone. In anesthetized, intact-chest dogs, infusion of MCI-154 (0.3-3 micrograms/kg/min i.v.) also exerted a positive inotropic effect. P.o. administrations of MCI-154 (10-300 micrograms/kg) increased dP/dtmax in conscious beagle dogs. The cardiotonic effect of MCI-154 was not attenuated by blockade of autonomic receptors, catecholamine depletion and prostaglandin synthesis inhibition. MCI-154 (0.3-30 micrograms i.a.) produced a direct vasodilator effect in the canine hind-limb. MCI-154 (3 and 30 micrograms/kg i.v.) was effective in heart failure models induced with high doses of propranolol or verapamil. The potent cardiotonic and vasodilator activities of MCI-154 revealed by the present study suggest that this agent would be an effective remedy for the treatment of heart failure.

Behavioral and biochemical changes following acute administration of MPTP and MPP+

The acute effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 1-methyl-4-phenylpyridinium ion (MPP+) on mouse locomotor activity and striatal dopamine (DA) and 5-hydroxytryptamine (5-HT) levels were investigated. A single dose of either MPTP (10-30 mg/kg, i.p.) or MPP+ (5-20 ug/mouse, i.c.v.) decreased locomotor activity 10-40 min after injection: this locomotor effect was significantly suppressed by either pretreatment with nomifensine or 1-deprenyl alone, or by the combination of desmethylimipramine and 6-hydroxydopamine. Pretreatment with clorgyline did not suppress this behavior and a single dose of haloperidol enhanced the effect. The striatal levels of DA, 3-methoxytyramine and 5-HT increased in parallel with the decrease in locomotor activity caused by MPTP or MPP+. In contrast, levels of 3,4-dihydroxyphenylacetic acid, homovanillic acid and 5-hydroxyindoleacetic acid were decreased by injection of either MPTP or MPP+. Possible mechanism(s) of the behavioral and biochemical changes caused by the acute actions of MPTP and MPP+ with respect to their neurotoxic effects on the nigrostriatal DA system are discussed.

Muscle cell differentiation in ascidian embryos analysed with a tissue-specific monoclonal antibody

Utilizing a muscle-specific monoclonal antibody (Mu-2) as a probe, we analysed developmental mechanisms involved in muscle cell differentiation in ascidian embryos. The antigen recognized by Mu-2 was a single polypeptide with a relative molecular mass of about 220 X 10(3). It first appeared at the early tailbud stage and continued to be expressed until the swimming larva stage. There were distinct and separate puromycin and actinomycin D sensitivity periods during the occurrence of the antigen, suggesting the new synthesis of the polypeptide by developing muscle cells. Embryos that had been permanently arrested with aphidicolin in the early cleavage stages up to the 32-cell stage did not express the antigen. DNA replications may be required for the antigen expression. Embryos that had been arrested with cytochalasin B in the 8-cell and later stages developed the antigen, and the number and position of the arrested blastomeres exhibiting the differentiation marker almost corresponded to those of the B4.1-line muscle lineage. Furthermore, in quarter embryos developed from each blastomere pair isolated from the 8-cell embryo, all the B4.1 as well as a part of b4.2 partial embryos expressed the antigen, while the a4.2 and A4.1 partial embryos did not show the antigen expression. These results may provide further support for the existence of cytoplasmic determinants for muscle cell differentiation in this mosaic egg.

Cell- and tissue-specific monoclonal antibodies in eggs and embryos of the ascidian Halocynthia roretzi

To obtain specific immunological probes for studying molecular mechanisms involved in the early embryonic development of ascidians, we have produced monoclonal antibodies directed against a homogenate of larvae of the ascidian Halocynthia roretzi. Among these, we have screened monoclonal antibodies that specifically recognize cells and/or tissues of the embryo. Characterization of six epidermis-specific monoclonal antibodies (including larval tunic-specific and larval fin-specific), three muscle-specific antibodies, two endoderm-specific antibodies, one notochord-specific antibody and two monoclonal antibodies that specifically recognize trunk-lateral cells suggests that these monoclonal antibodies may be useful as markers for analysing molecular mechanisms involved in specification of these cells. Seven monoclonal antibodies characteristically stain intercellular materials of the developing embryo and may therefore be valid for studying cellular construction of the embryo. Furthermore, monoclonal antibodies that recognize components of follicle cells, perivitelline space and sperm have also been established.

Myofibroblasts in basal cell epithelioma: with special reference to the phagocytic function of myofibroblasts

Three cases of basal cell epithelioma were studied with light and electron microscopy. Myofibroblasts, some containing melanosomes, were observed in the stroma of the tumors. The significance of these cells in the tumor is briefly discussed.

Right hepatic lobectomy for primary lymphoma: a case report and literature review

Primary lymphoma of the liver is an extremely rare entity; only eight cases have been reported in the literature. We treated a 34-year-old man with primary hepatic lymphoma by right hepatic lobectomy, including right hemicolectomy the nephrectomy. The histological diagnosis was a small cell diffuse histiocytic lymphoma. Details of this case plus that of others in the literature are described in this report.

Inhibition of rat brain monoamine oxidase by some analogues of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and 1-methyl-4-phenylpyridinium ion

To clarify the essential chemical structures of the neurotoxins, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its oxidized product, 1-methyl-4-phenylpyridinium ion (MPP+), that govern nigrostriatal dopamine neuron toxicity, interactions of several structurally related compounds of MPTP or MPP+ with monoamine oxidase (MAO) in rat forebrain homogenates were studied. Of the compounds tested, 4-phenyl-1,2,3,6-tetrahydropyridine (PTP), 4-phenylpyridine and 4-phenylpiperidine strongly and dose-dependently inhibited MAO-A and -B activity. Inhibition of PTP and 4-phenylpiperidine was MAO-A-selective, while that by 4-phenylpyridine was MAO-B-selective. Of these 3 compounds, only PTP time-dependently inhibited MAO-B, but not -A. Without preincubation, the modes of inhibition of MAO-A and -B by PTP were competitive. After 1 h preincubation, the mode of MAO-B inhibition changed to non-competitive, while inhibition of -A remained unchanged. PTP was oxidized by MAO-B, but not by -A, under these conditions. In contrast, 4-phenylpyridine and 4-phenylpiperidine were not substrates for either form of MAO in rat forebrain homogenates. These results, along with the other observations, indicate that PTP may essentially cause a neurotoxic effect on the nigrostriatal dopamine pathway.

Successful surgical treatment of pulmonary artery sling and partial anomalous pulmonary venous drainage in an infant

A 8 month old infant with pulmonary artery sling and partial anomalous pulmonary venous drainage was reported. The patient was seen initially with severe stridor. Diagnosis was made by barium swallow study, echocardiography, bronchoscopy, and pulmonary arteriography. The patient was operated on through a median sternotomy; the left pulmonary artery was dissected deep between the trachea and esophagus, and then reimplanted to the side of the main pulmonary artery. Systemic heparinization and microsurgical technique were used. Simultaneous intracardiac repair was carried out by means of extracorporeal circulation. The patient improved dramatically after operation. Postoperative pulmonary arteriogram revealed a wide patent left pulmonary artery, and postoperative perfusion lung scan confirmed improved perfusion of the left lung. It is concluded that pulmonary artery sling should be treated surgically as soon as diagnosed. From the surgical point of view, the left pulmonary artery should be anastomosed to the main pulmonary artery with micro-surgical technique to avoid late occlusion of the left pulmonary artery.

Light-induced potential and current across a large bacteriorhodopsin-asolectin planar membrane stabilized on a polyacrylamide gel surface

A phospholipid bilayer membrane was spread from an organic solvent solution between a polyacrylamide gel surface and an aqueous buffer solution. The membrane was quite similar to the conventional black lipid membrane, but was of a large size and was stable since it was supported on the gel surface. Bacteriorhodopsin, impregnated into the membrane, generated membrane potential and current upon illumination. The induced current was large, and this was attributed to the large area of the present membrane. Remarkable responses of the light-induced potential and current were also observed with a thick layer of organic solvent containing phospholipids. The effects of applied membrane potential, carbonylcyanide-m-chlorophenyl hydrazone (CCCP) and gramicidin were examined on these photoresponses. Steady-state current, which is due to protons flowing through the membrane, was enormously enhanced by applying membrane potential opposite to the photopotential or by adding gramicidin to the membrane-forming solution.

Recent advances in our understanding of the temporal control of early embryonic development in amphibians

Recent studies on temporal control of early amphibian development are reviewed. It is becoming clear that the development of an embryo is not timed by a single clock set in motion at fertilization, instead each developmental event seems to be timed by its own clock-like mechanism. The timing of developmental events is rigidly determined within embryonic cells, and usually can not be altered experimentally. One exception, however, is the timing of midblastula transition in amphibian embryos; recent studies have shown that its timing is regulated by the nucleocytoplasmic ratio. Several developmental events, particularly those associated with transcriptional activities, require DNA replication prior to their occurrence, suggesting an intimate relationship between DNA replication cycles and their onset. On the other hand, there are many other developmental events where timing is not controlled by the number of cell divisions, DNA replication cycles, or the nucleocytoplasmic ratio. Cytoplasmic machinery with autonomous oscillatory properties is thought to be involved in the timing of these events.

Protein tyrosine kinase activity of eggs of the sea urchin Strongylocentrotus purpuratus: the regulation of its increase after fertilization

Protein tyrosine kinase activity in eggs of the sea urchin, Strongylocentrotus purpuratus, increased two- to fourfold as early as several min after fertilization at 8-10 degrees C. Artificial activation of eggs with the divalent cation ionophore, A23187, or with butyric acid induced the increase in enzyme activity. The transfer of eggs to seawater containing either no Na+ or 50 mM Na+ and 10(-4) M amiloride immediately after fertilization did not block the increases in enzyme activity. When eggs were activated with seawater containing NH4OH, enzyme activity did not increase at 1 hr after activation, although the increased activity was detected at 3 hr after activation. Increased enzyme activity also was observed in enucleated egg fragments activated with butyric acid. Puromycin and emetine, inhibitors of protein synthesis, also did not inhibit the initial increases of enzyme activity after fertilization. These results demonstrated that the increased protein tyrosine kinase activity observed after fertilization of S. purpuratus eggs can be initiated independent of various other known events such as fusion with sperm cells and protein and DNA synthesis.

Cell lineage analysis in ascidian embryos by intracellular injection of a tracer enzyme. II. The 16- and 32-cell stages

Cell lineages during development of ascidian embryos were analyzed by injecting horseradish peroxidase as a tracer enzyme into identified cells of the 16-cell and 32-cell stage embryos of Halocynthia roretzi. Most of the blastomeres of these embryos developed more kinds of tissues than have hitherto been reported, and therefore, the developmental fates of each blastomere are more complex. It has been thought that every blastomere of the 64-cell stage ascidian embryo gives rise to only one kind of tissues, but the finding that the several blastomeres at the 32-cell stage developed into at least three different kinds of tissues, clearly indicates that the stage at which the fates of every blastomere are determined to one tissue is later than the 64-cell stage. The results also clearly demonstrate that muscle cells are derived not only from B-line cells (B5.1, B5.2, B6.3, and B6.4) but also from A-line cells (A5.2 and A6.4) and b-line cells (b5.3 and b6.5). Based on the present analysis as well as other studies, complete cell lineages of muscle cells up to their terminal differentiation have been proposed. In addition, lineages of nervous system, notochord, and epidermis are also discussed.