M1 receptors in blood pressure-controlled ischemic spontaneously hypertensive rats

BACKGROUND AND PURPOSE

Hypertension is a primary aggravating factor in cerebral infarction. An acute rise in blood pressure (BP) at the time of a stroke may be harmful to the brain in a hypertensive subject because both cerebral vascular structure and function are altered by hypertension. Muscarinic M1 receptors are concerned with memory and learning. We aimed to evaluate the effect of controlling BP in hypertensive subjects at the time of stroke with a biochemical index of brain damage.

METHODS

We gave a single dose of either the antihypertensive alpha-blocker phentolamine (2 mg/kg IP) or the calcium antagonist nicardipine (2 mg/kg IP) at the start of bilateral carotid artery occlusion to spontaneously hypertensive rats undergoing 3 hours of transient ischemia; we measured the time course of mean BP (MBP) and changes in the M1 receptor and its mRNA in three brain regions 2 weeks after the transient ischemia.

RESULTS

Administration of phentolamine or nicardipine not only significantly suppressed the ischemia-induced rise of MBP, it actually decreased MBP during ischemia. In an ischemic control group, M1 receptor binding decreased in the frontal cortex and M1 receptor mRNA increased in the hippocampus 2 weeks after the ischemia. In contrast, both phentolamine- and nicardipine-treated ischemic rats showed no changes in either index compared with sham-operated controls.

CONCLUSIONS

Controlling BP during an ischemic insult attenuates ischemia-induced damage of M1 receptors in the brain of spontaneously hypertensive rats. These results suggest that a rapid intensive increase of BP at the time of a stroke may exacerbate brain damage in hypertensive individuals.

Immediate hypersensitive reactions to buckwheat ingestion and cross allergenicity between buckwheat and rice antigens in subjects with high levels of IgE antibodies to buckwheat

BACKGROUND

Immediate hypersensitive reactions induced by buckwheat ingestion are considered to be IgE-mediated. Some subjects, however, develop no immediate adverse reactions after buckwheat ingestion despite high levels of buckwheat-specific antigens IgE. The mechanism is unknown.

OBJECTIVE

To investigate the mechanisms.

METHODS

RAST for buckwheat and rice and RAST inhibition between these antigens were performed using sera from 23 buckwheat-sensitive subjects and 30 buckwheat-tolerant subjects who had IgE antibodies for both buckwheat and rice.

RESULTS

RAST values for buckwheat and rice were significantly correlated with each other (P < .01) in the buckwheat-tolerant group, but not in the buckwheat-sensitive group. This suggests the IgE antibodies from the subjects without any overt symptoms after buckwheat ingestion recognize the cross-reactive epitope between buckwheat and rice, whereas the IgE antibodies from those with immediate reactions to buckwheat ingestion do not. RAST inhibition assays were performed to evaluate this. RAST inhibition of heterogeneous combination of inhibitor and disc antigen such as rice and buckwheat was significantly smaller than that of homologous combination of rice and rice or buckwheat and buckwheat in the group with immediate symptoms after buckwheat ingestion. There was no significant difference in RAST inhibition between homologous and heterogeneous combinations in the group without the symptoms.

CONCLUSIONS

There was cross-reactivity with IgE antibodies between buckwheat and rice and IgE antibodies from the buckwheat-tolerant subjects with high levels of IgE antibodies from the buckwheat might recognize the epitopes on buckwheat antigens which cross-react with rice antigens, whereas IgE antibodies from the buckwheat-sensitive subjects might bind to buckwheat-specific epitopes.

Inhibitory effect of tyrphostin on the replication of herpes simplex virus type 1

Tyrphostins 9 and 47, inhibitors of protein-tyrosine kinase, inhibited the replication of herpes simplex virus type 1 (HSV-1), whereas tyrophostin 1, which does not inhibit protein-tyrosine kinase, did not affect the replication of HSV-1. The inhibitory effect of tyrphostin 9 was more potent than that of tyrphostin 47, and the IC50 of tyrphostin 9 was 40 nM. Sodium orthovanadate, an inhibitor of protein phosphotyrosine phosphatase, increased HSV-1 plaque formation and its effect was partly reversed by tyrphostin 9. The phosphorylation of viral phosphoproteins was decreased by tyrphostin 9 in a dose-dependent manner, but the tyrphostin 9-induced reduction of protein synthesis was not dose-dependent. At the late stage of infection, tyrosine phosphorylation was demonstrated in HSV-1 phosphoproteins. These results indicate that protein-tyrosine kinase is involved in the replication of HSV-1 and that tyrphostin can inhibit the synthesis and post-translational phosphorylation of the viral proteins.

Cytosolic Ca2+ dynamics in hamster ascending thin limb of Henle's loop

Intracellular calcium plays an important role in the regulation of Cl- reabsorption in the ascending thin limb of Henle's loop (ATL). To elucidate the cytosolic Ca2+ dynamics in the ATL, intracellular Ca2+ concentration activity ([Ca2+]i) was measured in the in vitro microperfused hamster ATL using fura 2. Basal [Ca2+]i was 89.1 +/- 7.3 nM (n = 9 tubules). Removal of Ca2+ from the peritubular solution decreased [Ca2+]i from 89.1 +/- 7.3 to 64.1 +/- 7.1 nM in 2 min (n = 9, P < 0.05), whereas [Ca2+]i did not change after removal of Ca2+ from the luminal solution. Addition of 1 mM NaCN to the bath increased [Ca2+]i. This effect was completely abolished by the elimination of ambient Ca2+. Trifluoperazine and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) in the bath reversibly increased [Ca2+]i, whereas addition of 1 mM ouabain to the bath decreased [Ca2+]i. Rates of changes in [Ca2+]i after removal and replacement of basolateral Ca2+ were not affected by removal of Na+, K+, or Cl- from the bath, whereas nicardipine decreased these parameters. Increasing bath K+ from 5 to 100 mM decreased [Ca2+]i from 69.3 +/- 5.8 to 50.8 +/- 5.0 nM in 1 min (n = 6, P < 0.05). Subsequent reduction of K+ from 100 to 5 mM increased [Ca2+]i to 174.0 +/- 30.8 nM in 1 min, followed by a gradual decrease in [Ca2+]i to a steady-state level of 74.2 +/- 8.0 nM in 2 min. Changes in basolateral K+ concentration did not affect [Ca2+]i in the absence of ambient Ca2+.(ABSTRACT TRUNCATED AT 250 WORDS)

Concomitant use of prostaglandin E1 and prednisolone; inhibition of superoxide anion production by polymorphonuclear leucocytes

We investigated the effect of prostaglandin E1 (PGE1) or prednisolone on superoxide anion production by polymorphonuclear leucocytes (PMN) stimulated by opsonized zymosan (OZ). The production of superoxide anion by PMN was significantly suppressed by treatment with either PGE1 or prednisolone. Concomitant use of PGE1 and prednisolone suppressed it significantly more than PGE1 or prednisolone alone. Both PGE1 and prednisolone suppressed the Ca2+ influx into PMN, which was a crucial event for production of superoxide anion in stimulation by OZ. The effect of concomitant use of PGE1 and prednisolone in vivo was confirmed in rat peritonitis. The additional use of PGE1 with prednisolone may provide a strategy to reduce the amount of prednisolone required in treatments.

Morphology of a cytochrome c-adsorbed stearic acid monolayer on Brewster angle microscopy

The morphologies of stearic acid and cytochrome c (cyt.c)-adsorbed stearic acid monolayers were investigated by Brewster angle microscopy (BAM) with various molecular areas of stearic acid. With an area of more than 0.38 nm2/molecule, many blight island domains and some bright circles were observed in the BAM image of the stearic acid monolayer. The blight site part became to occupy all the surface with compression, and then became more closely packed with an area of 0.22 nm2/molecule. On the other hand, a different BAM image was obtained for the cyt.c-adsorbed stearic acid monolayer, as follows: (i) a striped pattern was only observed in the presence of cyt.c; (ii) the number of bright circles in the presence of cyt.c was less than that in its absence. Furthermore, when a uniform BAM image was observed for the stearic acid monolayer with cyt.c, the intensity of the absorbance at 409 nm of cyt.c was the highest. By calculating the amount of cyt.c adsorbed on a stearic acid monolayer from the absorbance value, it was shown that cyt.c was most closely packed when an uniform BAM image was observed. These results suggest that the use of BAM and visible absorption spectroscopy together is useful for studying the morphology of a monolayer.

Metallothionein null cells have increased sensitivity to anticancer drugs

Overexpression of metallothioneins (MTs) protects some cells against heavy metals, mutagens, anticancer agents, and reactive oxygen species. We have examined the effect of the loss of MT expression on the cytotoxicity of anticancer agents and mutagens using embryonic fibroblast cells from transgenic mice with targeted disruptions of MT I and II genes (MT -/-). MT -/- cells expressed no detectable MT. Compared to wild type cells, MT -/- cells showed enhanced sensitivity to a 2-h exposure to cisplatin, melphalan, bleomycin, cytarabine, or N-methyl-N'-nitro-N-nitrosoguanidine but were equally sensitive to doxorubicin and neocarzinostatin. Basal expression of the DNA damage-response genes, gadd 45 and gadd 153, were elevated in MT -/- cells compared to MT +/+ cells. Anticancer drug treatment, however, did not produce a greater increase in gadd 45 or gadd 153 expression in MT null cells compared to MT +/+ cells. These results support the hypothesis that endogenous MT levels affect the sensitivity of mammalian cells to mutagens and clinically important anticancer drugs.

Growth patterns and interstitial invasion of small hepatocellular carcinoma

Twenty-five cases of small hepatocellular carcinoma (HCC; diameter < or = 30 mm) were evaluated for overall morphologic features and growth patterns. The tumors often showed a well-differentiated, normotrabecular histologic pattern and insidious interstitial invasion, which resembled benign hepatocytes scattered in connective tissues. As the tumor grew, a less-differentiated tumor area became predominant. Portal tracts included in small HCC nodules were quantitatively assessed, revealing that they progressively reduced in number with tumor growth. The tumor margin was often reported to be unclear. The present results indicate that the histologic grade of tumor differentiation, capsular formation, existence of liver cirrhosis and patterns of interstitial invasion are important factors for determining the nature of the margin. The score of argyrophilic nuclear organizer regions (AgNOR) was examined in 5 cases showing typical interstitial invasion with the insidious type. In each case, the AgNOR score of the invading tumor cells was lower than that of tumor cells within the HCC nodules, but higher than benign hepatocytes in cirrhotic parenchyma. It clarified that the growth activity of well-differentiated HCC was rather suppressed upon their interstitial invasion.

Interaction of calponin with phospholipids

The interaction between chicken gizzard calponin and phospholipids was examined by sedimentation assay and affinity chromatography. Calponin was sedimented with phosphatidylserine (PS) and phosphatidylinositol (PI) vesicles but not with phosphatidylcholine (PC) vesicles. The apparent Kd values of calponin to PS and PI were calculated to be 1.3 x 10(6) and 1.5 x 10(6) M-1, respectively. Domain mapping with chymotryptic digestion showed that the phospholipid-binding site resided within the N-terminal 22-kDa fragment, in which the bindings of actin, calmodulin, S100, and tropomyosin also occur. The amount of calponin bound to PS and PI vesicles decreased with increasing ionic strength or Ca2+ concentrations. The presence of MgCl2 was needed for the calponin-PS vesicle interaction. Calponin-binding proteins including actin, calmodulin, and S100 inhibited calponin binding to the phospholipid vesicles in a concentration-dependent manner, while tropomyosin had little effect on the binding. The inhibitory effects of calmodulin and S100 were found only in the presence of CaCl2. Neither caldesmon nor SM22 affected the binding.

Increased incidental detection and reduced mortality in renal cancer--recent retrospective analysis at eight institutions

A retrospective survey of renal cell carcinoma between 1975 and 1993 at eight collaborating institutions was conducted with special reference to the incidental detection and mortality of renal cancer. The analysis demonstrated a recent dramatic increase in the frequency of incidental renal cancer, which now comprises two-thirds of all renal cancers, and a simultaneous recession in non-incidental or suspected renal cancer. Incidental renal cancer has remained unchanged during the last decade as far as patient demographics, occasion and method of detection, and the degree of tumor extension are concerned. On the other hand, the annual number of deaths from renal cancer has significantly decreased, and kidney-sparing surgery has been more frequently performed. These results indicate that incidental renal cancers are now in the majority, and earlier detection may contribute to improving the mortality and morbidity from the disease as a whole.

Therapeutic effect of percutaneous ethanol injection on small hepatocellular carcinoma: evaluation with CT

PURPOSE

To evaluate the therapeutic effect of percutaneous ethanol injection (PEI) on small hepatocellular carcinoma (HCC) with computed tomography (CT).

MATERIALS AND METHODS

Sixty-seven patients with histologically proved HCC 3 cm or less in diameter underwent PEI. The patients were regularly followed up with sonography and contrast material-enhanced CT for more than 1 year (range, 12-96 months). The CT findings were evaluated for three tumor types distinguished on the basis of their appearance relative to that of the surrounding liver parenchyma: type 1 = hyperattenuating at the early phase (n = 39), type 2 = iso- or hypoattenuating at the early phase and hypoattenuating at the late phase (n = 18), and type 3 = isoattenuating (not detected) at both the early and late phases (n = 10).

RESULTS

After PEI, a necrotic area of HCC and the surrounding liver parenchyma was characterized as hypoattenuating at both early and late phases of contrast-enhanced CT, regardless of the type. When an HCC appeared to be completely necrotic within 3 months after PEI, this status was retained until the latest observation in all but three cases.

CONCLUSION

Contrast-enhanced CT can correctly depict PEI-induced necrosis in HCC and is reliable for evaluating the therapeutic effect of PEI.

Cholecystokinin alterations and effects of levodopa administration in the MPTP-treated mouse brain

To clarify the effects of levodopa administration on MPTP-induced alterations in neuropeptides, we examined the effects of repeated levodopa injections (200 mg/kg i.p.) for 2 weeks starting 4 weeks after 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment (30 mg/kg i.p. twice/day for 5 days) on cholecystokinin-octapeptide (CCK-8), substance P (SP) and thyrotropin-releasing hormone (TRH) concentrations at 6 weeks after the MPTP treatment. In the striatum, CCK-8 significantly but slightly decreased in the MPTP-treated mice, coinciding with the MPTP-induced marked reduction of dopamine (DA). This considerable reduction of striatal CCK-8 may result from the selectivity of MPTP since the mesolimbic DA neurons coexisting with CCK-8 are intact with the MPTP treatment. Furthermore, this MPTP-induced decrease in CCK-8 persisted with repeated levodopa administration; therefore, the ineffectiveness of the levodopa treatment may have been be due to the degeneration of the nigrostriatal DA neurons. SP and TRH contents showed little or no change with levodopa treatment in the MPTP-treated mouse brain. The CCK-8 level decreased in the thalamus+midbrain, hippocampus and hindbrain of the MPTP+levodopa-treated group, although there were no changes in the MPTP-treated controls. These results suggest that DAergic neurons, except those in the nigrostriatum, strongly interact with the CCK neurons in these brain regions.

Vasopressin stimulates Cl- transport in ascending thin limb of Henle's loop in hamster

The effect of arginine vasopressin (AVP) on NaCl transport was investigated in the isolated microperfused hamster ascending thin limb of Henle's loop by measuring transepithelial voltage (Vt) and transmural 22Na+ and 36Cl- fluxes. In the presence of a transmural NaCl concentration gradient (100 mM higher in the lumen), Vt was 8.4 +/- 0.4 mV. Addition of 1 nM AVP to the basolateral solution increased Vt to 9.6 +/- 0.4 mV, which corresponds to an increase in the Cl- to Na+ permselectivity ratio (PCl/PNa) from 2.8 +/- 0.2 to 3.4 +/- 0.2. AVP at physiological concentrations increased Vt in a dose-dependent manner with an ED50 of 5 pM. AVP increased the Cl- efflux coefficient from 99.6 +/- 6.3 to 131.4 +/- 10.6 x 10(-7) cm2/s without affecting the Na+ efflux coefficient. 5-Nitro-2-(3-phenyl-propylamino)-benzoate (0.2 mM), a Cl- channel inhibitor, in the perfusate decreased the basal Cl- efflux coefficient and inhibited the AVP-induced increase in this parameter. The AVP-induced increase in Vt was not affected by [d(CH2)5(1),O-Me-Tyr2,Arg8] vasopressin, a V1 receptor antagonist, but was abolished by [d(CH2)5,D-Ile2,Ile4,Arg8] vasopressin, a V2 receptor antagonist. The selective V2 agonist dDAVP in 1 nM also increased Vt from 8.6 +/- 0.7 to 9.5 +/- 0.6 mV. Dibutyryl cAMP and forskolin both increased Vt, whereas H89, an inhibitor of cAMP-dependent protein kinase, abolished the AVP-induced increase in Vt. These results demonstrate that AVP stimulates Cl- transport in the ascending thin limb of Henle's loop by activating Cl- channels via a signal transduction cascade comprising V2 receptors, adenylate cyclase, and cAMP-dependent protein kinase. The ascending thin limb of Henle's loop thus participates in the formation of concentrated urine as one of the target renal tubular segments of AVP.

Intracellular cross-talk between thyrotropin receptor and A1 adenosine receptor in regulation of phospholipase C and adenylate cyclase in COS-7 cells transfected with their receptor genes

COS-7 cells were transiently transfected with human thyrotropin receptor (TSHR) and dog A1 adenosine receptor (A1R) cDNA. TSH stimulated both inositol phosphate production and cyclic AMP (cAMP) accumulation in the cells. An A1 agonist, N6-(L-2-phenylisopropyl)adenosine (PIA), which is ineffective alone, significantly enhanced TSH-induced inositol phosphate production, but insignificantly inhibited TSH-induced cAMP accumulation was revealed by short-term treatment with the protein kinase C inhibitors, staurosporine and K252a, or long-term treatment with 12-myristate 13-acetate, suggesting that endogenous protein kinase C inhibits the A1R-mediated inhibition of the TSHR-adenylate cyclase system. In staurosporine-treated cells, the stimulatory and inhibitory permissive actions of PIA on TSH-induced phospholipase C and adenylate cyclase activation respectively were completely reversed by pretreatment with pertussis toxin whereas intrinsic TSH-induced effects were hardly affected by the toxin. The cross-talk between the signalling pathway for TSHR and that for A1R was not detected in a mixture of cells expressing either TSHR or A1R. We conclude that a single species of A1R, via pertussis-toxin-sensitive GTP-binding proteins, not only inhibits adenylate cyclase but also stimulates phospholipase C in collaboration with an activated TSHR within a single cell expressing both types of receptor.

Enhanced sensitivity to oxidative stress in cultured embryonic cells from transgenic mice deficient in metallothionein I and II genes

Embryonic cells from transgenic mice with targeted disruption of metallothionein I and II genes expressed no detectable metallothionein either constitutively or after treatment with cadmium, in contrast to cultured cells that were wild type or heterozygous for the loss of the metallothionein genes. Metallothionein null cells were most sensitive to the cytotoxic effects of cadmium, the membrane permeant oxidant tert-butylhydroperoxide, and the redox cycling toxin paraquat. No marked differences were seen among the wild type, heterozygous, or metallothionein null cells in glutathione levels or in the activity of CuZn-superoxide dismutase, glutathione peroxidase, or catalase. Nevertheless, metallothionein null cells were more sensitive to tert-butylhydroperoxide-induced oxidation as ascertained by confocal microscopic imaging of dichlorofluoroscein fluorescence. These results indicate basal metallothionein levels can function to regulate intracellular redox status in mammalian cells.

An enzymatic formation of 13-oxo-trideca-9,11-dienoic acid from 13-hydroperoxylinolenic acid by a homolytic hydroperoxide lyase in elicitor-treated soybean cotyledons

An activity of homolytic hydroperoxide lyase (HPLS) catalyzing the specific cleavage of 13-hydroperoxylinolenic acid to form a volatile compound and 13-oxo acid was found in the enzyme extract from soybean cotyledons. 2-Penten-1-ol was characterized as a volatile metabolite by gas chromatography-mass spectrometry analysis. The methyl ester derivatives of reaction products were separated and isolated by a normal-phase high-performance liquid chromatography, and identified to be 13-oxo-trideca-9(Z),11(E)-dienoic acid methyl ester and its geometric isomer possessed 9(E),11(E) moiety by the analyses of high resolution mass spectrometry and nuclear magnetic resonance spectrometry. An activity of homolytic HPLS found in soybean cotyledons was evidently enhanced by elicitation. The products of 13-oxo-tridecadienoic acid with alpha, beta, gamma, delta-unsaturation were shown to be antifungal substances by a chromatographic bioassay. The metabolites via lipoxygenase and HPLS pathways may have physiological roles in the resistant action of host plants.

New aerodynamic aspects of nasal patency

In considering possible aerodynamic indicators of subjective nasal stuffiness, we measured nasal resistance, acceleration change of nasal airflow, and alteration of differential pressure and compared those with the degree of severity of sensation of nasal obstruction in 75 patients. The acceleration change of airflow and alteration of differential pressure are presented as an equation: y = ax2 + bx + c, in which "a" represents the approximate shape of the curve. Nasal resistance, on either inspiration or expiration, and coefficient "a" of acceleration change the rapid phase from inspiration to expiration correlated well with subjective nasal patency, while coefficient "a" of acceleration change the rapid phase from expiration to inspiration and alteration of differential pressure either the rapid phase from inspiration to expiration or from expiration to inspiration did not correlate well with perception of nasal blockage. It seems that measurement of respiratory acceleration of airflow of quiet nasal breathing is a useful indicator of subjective nasal patency.

Cyclosporin A prevents ischemia-induced reduction of muscarinic acetylcholine receptors with suppression of microglial activation in gerbil hippocampus

We previously reported the late onset reduction of muscarinic acetylcholine receptors (LORMAR) which begins 7 days after a 5-min period of experimentally induced forebrain ischemia in the gerbil hippocampus. This study demonstrated that post-ischemic administration of cyclosporin A (CsA) reduced LORMAR 10 days after 5 min of forebrain ischemia in the gerbil hippocampus, suggesting that immunosuppression by CsA may reduce damage to the cholinergic system after ischemia. Microglia positive for HLA-DR class II antigen which presented in the hippocampal CA1 area, the region most vulnerable to ischemia, were also reduced by CsA. CsA may suppress microglial activation especially with regard to the antigen-presenting function, and LORMAR may be attenuated by this modulation of microglial function.

Immunohistochemical detection of aberrant p53 expression in hepatocellular carcinoma: correlation with cell proliferative activity indices, including mitotic index and MIB-1 immunostaining

We analyzed the p53 expression immunohistochemically in 50 specimens of hepatocellular carcinoma (HCC) using two monoclonal antibodies (DO7 and PAb1801) and one polyclonal antibody (CM1), which recognize both wild and mutant type p53 proteins and can be used for paraffin-embedded sections. Fifteen of the 50 HCC specimens (30%) showed p53 expression localized at tumor nuclei, and this expression was significantly more frequent in HCCs with histologically lower differentiation. Except for serum titers of alpha-fetoprotein, the p53 expression had no statistically significant correlation with clinicopathological parameters, including hepatitis virus infection, tumor size, and background liver diseases. Conversely, the cell proliferative activities of tumor cells as assessed by mitotic index and immunostaining for MIB-1 were well correlated with the grade of histological differentiation. Moreover, MIB-1 immunostaining was shown to be useful in distinguishing well differentiated HCC from hepatocytes in chronic liver diseases. It also was shown that p53 expression was strongly associated with cell proliferative activity. Our results indicate that p53 expression takes place in the late stage of tumor progression and is related to the high malignant potential of HCCs.

Protective effects of pergolide on dopamine levels in the 6-hydroxydopamine-lesioned mouse brain

Pergolide, along with bromocriptine and lisuride, is one of the most active dopamine receptor agonists. To determine whether or not pergolide protects against dopaminergic neuronal damage, via its activity on monoamine metabolism, we studied the effects of pergolide pretreatment on changes in monomaines and their metabolites in the mouse striatum after intracerebroventricular injection of 6-hydroxydopamine with pretreatment of desipramine. After intracerebroventricular administration of 6-hydroxydopamine (40 micrograms) in mice, the levels of dopamine and its metabolites (DOPAC, HVA) in the striatum rapidly decreased to 49%, 29% and 68%, respectively, of the naive controls at week 1 but then gradually recovered to control levels at weeks 2 and 4. Repeated pretreatment with pergolide (0.5 mg/kg, i.p.) for 7 days before administration of 6-hydroxydopamine, almost completely protected against reduction in striatal dopamine and its metabolites 1 week after injection of 6-hydroxydopamine. Therefore, pergolide could normalize the decreased dopamine synthesis or storage, and has a neuroprotective effect against dopaminergic dysfunction induced by the neurotoxin, 6-hydroxydopamine. Although we found that pergolide did not show radical scavenging activity in an in vitro system that generated hydroxyl radicals, it has been reported in vivo that pergolide treatment may induce Cu/Zn superoxide dismutase in the rat striatum. Considering these findings, pergolide may well be protective to dopaminergic neurons, largely because of its effects on presynaptic autoreceptors and on its induction of Cu/Zn superoxide dismutase. Further research on the neuroprotective effects of pergolide in Parkinson disease models, by injection of 6-hydroxydopamine, is needed to clarify its mechanism of action on dopaminergic indices.

Limited development capacity of the earliest embryonic murine thymus

Previous studies have demonstrated that murine thymus separates from the pharynx during 11.5-12 days of gestation, and that the proliferation of thymic cells starts at this age. We characterized embryonic day 12 thymus in terms of the surface phenotype of the thymus cells, the function of the lobe in supporting T cell development in organ culture, and the precursor activity of the thymus cells in a mixed culture with deoxyguanosine-treated lobes. The phenotype of the major population of embryonic day 12 thymus cells was HSA+, CD44+, c-kit+, Thy-1-, CD25-, CD4-, CD8-, TcR-, and Sca-1-. In organ culture of embryonic day 12 thymus lobes, most of the lobes did not develop well and failed to generate CD4+CD8+, CD4+CD8-, or CD4-CD8+ cells, even when embryonic day 14 thymus cells were added. However, thymus cells on embryonic day 12 contained T cell precursors that developed into mature T cells in co-culture with deoxyguanosine-treated fetal thymic lobes. The majority of the stromal cells in deoxyguanosine-treated embryonic day 14 thymus lobes expressed the surface molecules I-A and H-2D, whereas these cells in embryonic day 12 thymus lobes were negative for these surface molecules. Thus, our findings suggest that the embryonic day 12 thymus lobe contains T cell precursors, but that the undeveloped thymic stromal cells are insufficient to support full T cell development.

Amiloride-sensitive Na+/H+ antiporter in basolateral membrane of hamster ascending thin limb of Henle's loop

The mechanisms of intracellular pH (pHi) regulation were investigated in the in vitro microperfused hamster ascending thin limb (ATL) of Henle's loop with the fluorescent pH indicator, 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein. pHi of ATL cells was 7.05 +/- 0.02 (n = 30) when microperfused with a CO2/HCO(3-)-buffered solution. In HEPES-buffered solution, pHi was 7.10 +/- 0.02 (n = 16), which was significantly higher than the value in CO2/HCO(3-)-buffered solution (P < 0.05, n = 16). In HEPES-buffered solution, elimination of Na+ and addition of 1 mM amiloride to basolateral solution decreased the pHi by 0.12 +/- 0.03 (n = 6) and 0.11 +/- 0.02 (n = 5) at 1 min, respectively. The same manipulations in the luminal solution had no effect on pHi. One millimolar of N-ethylmaleimide (NEM) added to either side of ATL caused no significant change in pHi. Elimination of K+ on either side of ATL did not alter pHi. After adding 20 mM NH4Cl to basolateral solution, pHi instantaneously increased from 7.17 +/- 0.01 to 7.51 +/- 0.03 (n = 3), and then returned to steady-state level of 7.21 +/- 0.05 (n = 15) in 3 min. Removal of NH4Cl from basolateral solution then caused a rapid fall in pHi to 6.31 +/- 0.05 (n = 15), followed by spontaneous recovery at a rate of 0.43 +/- 0.06 unit/min (n = 15).(ABSTRACT TRUNCATED AT 250 WORDS)

[Hypotonous maculopathy following trabeculectomy with mitomycin C]

We retrospectively studied incidence, prognosis and predictive factors of hypotonous maculopathy following trabeculectomy with adjunctive mitomycin C. The subjects were 208 cases (208 eyes) with various types of glaucoma with clear media, who were followed up for at least three months postoperatively. The follow up periods ranged from 3 to 44 months with a mean of 21.1 months. The incidence of the maculopahy was 9.1% (19/208). The postoperative intraocular pressures (IOPs) varied between 1 and 6 mmHg in the presence of maculopathy. The maculopathy disappeared in 14 eyes (74%) spontaneously or following ocular hypertensive therapy including application of trichloracetic acid and subconjunctival injection of autologous blood. The final visual acuity deteriorated two lines or more in 8 eyes (42%). A discriminant analysis showed that age, history of intraocular surgery, preoperative maximum IOP, and mean deviation are the predictive factors for maculopathy. As compared with the hypotonous eyes without maculopathy, those with maculopathy tended to be younger and to have less severe visual field changes.