[Studies on solid phase extraction of bile acids from biological matrix]

To quantify bile acids in biological samples, a solid phase extraction method was examined. This method is known as simpler procedures with less contamination compared with solvent extraction methods. Rat bile, feces and urine were used as biological samples. Since Bond Elut C18 and C8 were proved to be more suitable than the other phases (CH and SAX) so far examined using standard bile acids, Bond Elut C18 was used for biological samples. Quantification of biological sample was carried out by gas chromatography after the extracted sample was derivatized to methyl ester by treatment with trimethylsilyldiazomethane then to trifluoroacetyl ester by trifluoroacetic anhydride. On the gas chromatography, two columns (Rtx-50 and Rtx-200) were connected to the injector with Y-tube for elimination of interference. Except for a few bile acids, high recovery with less biological contamination was obtained by this solid phase extraction method.

Stimulatory effect of leminoprazole on secretion and synthesis of mucus by rabbit gastric mucosal cells

We examined whether leminoprazole (an acid pump inhibitor) enhances the secretion and synthesis of gastric mucus in vitro. Mucosal cells were prepared from male rabbit stomachs, and the amounts of secreted and synthesized mucus were determined by the [3H] glucosamine labeling method. Exposure of gastric mucosal cells to leminoprazole at 1 to 100 microM for 8 hr caused significant increases in the secretion and synthesis of mucus in a dose-related manner, but omeprazole was not effective. The stimulatory effects of leminoprazole on secretion and synthesis were observed 4 hr and 6 hr later, respectively. In contrast, both 16,16-dimethyl prostaglandin E2 and nitroprusside, a nitric oxide (NO) generator, caused marked increases in mucus secretion and synthesis even after 2-hr incubation. The effects of leminoprazole on gastric mucus were strongly inhibited by NO synthase inhibitors such as NG-nitro-L-arginine methyl ester and NG-monomethyl-L-arginine and by the NO scavenger oxyhemoglobin. However, neither indomethacin (an inhibitor of cyclooxygenase), aminoguanidine (an inhibitor of inducible nitric oxide synthase) nor cycloheximide (a protein synthesis inhibitor) could suppress its effects. These results suggest that leminoprazole stimulates the secretion and synthesis of gastric mucus after a lag period, probably through NO produced by constitutive NO synthase.

Inhibition of tumor necrosis factor in the brain suppresses rabbit sleep

Tumor necrosis factor (TNF) is a cytokine that possesses many biological activities, including enhancement of non-rapid-eye-movement sleep (NREMS). The role of endogenous TNF in the regulation of spontaneous sleep is unknown. If TNF is involved in sleep regulation, then reduction of endogenous TNF should suppress spontaneous sleep. A soluble TNF-binding protein I (TNF-BP I) and a synthetic fragment of TNF-BP I, TNF-R-(159-178), that contains the biologically active region of TNF-BP I, were used. These substances bind TNF and possess TNF-inhibitory activity; their effects on rabbit sleep after intracerebroventricular injection were determined across a 6-h recording period. Two doses of TNF-BP I (0.05 micrograms and 0.5 micrograms) were administered; the higher dose of TNF-BP I significantly decreased NREMS. Four doses of TNF-R-(159-178) (0.25 micrograms, 2.5 micrograms, 25 micrograms and 50 micrograms) were used. The 25 micrograms and 50 micrograms doses significantly suppressed NREMS. The highest dose (50 micrograms) also decreased REM sleep. These results are consistent with the hypothesis that endogenous brain TNF is involved in the regulation of normal sleep.

Role of C5a-ase in group B streptococcal resistance to opsonophagocytic killing

Type III group B streptococci (GBS) can be subdivided into three subtypes, RDP III-1, III-2, and III-3, on the basis of numerical analysis of HindIII restriction endonuclease digestion patterns (HindIII RDP) with their chromosomal DNAs. In the present study, the effect of C5a on opsonophagocytic killing of a representative strain from each RDP type was investigated by using a novel optical method for determining opsonophagocytic killing, and the effect of C5a-ase treatment of C5a on opsonophagocytic killing was also investigated. Pre-stimulation of polymorphonuclear leukocytes (PMNs) with C5a significantly increased opsonophagocytic killing of all three strains. The increase in killing was abolished by pretreating the C5a with GBS that express C5a-ase, a treatment that also destroyed the chemoattractant activity of the C5a. The kinetics of killing of the RDP III-2 strain differed from those of the other two strains. The survival of the RDP III-2 bacteria continued to decline over the entire 60-min incubation of the opsonophagocytic assay when PMNs were prestimulated with C5a or with C5a that had been inactivated with GBS C5a-ase (dC5a). In contrast, killing of the RDP III-1 and III-3 strains almost ceased after 20 or 60 min when PMNs were prestimulated with dC5a or C5a, respectively. A difference in bacterial killing between the III-2 strain and the III-1 and III-3 strains therefore became increasingly apparent with prolonged incubation time. The percentage of bacteria surviving in the extracellular fluid was approximately the same as the percentages of bacteria surviving in both intracellular and extracellular locations when PMNs were prestimulated with either C5a or dC5a. These data imply that the majority of bacterial killing occurred following phagocytosis and suggest that the enhanced killing of GBS following prestimulation of PMNs with C5a resulted from increased ingestion of the bacteria.

A histamine H2 receptor antagonist, roxatidine, stimulates mucus secretion and synthesis by cultured rabbit gastric mucosal cells

We examined the effects of the known antisecretory and mucosal protective drug, roxatidine, on the secretion and synthesis of mucus by cultured rabbit gastric mucosal cells. The amounts of secreted and synthesized mucus were determined by the [3H] glucosamine labelling method. Exposure of the cells to roxatidine for 8 hr caused increases in the secretion and synthesis of mucus in a dose-related manner. The increase in mucus synthesis was maximally induced 4 hr after the addition of roxatidine, while mucus secretion was maximally enhanced a further 4 hr later. However, other H2 antagonists such as cimetidine, rantidine and famotidine failed to stimulate the secretion and synthesis of gastric mucus. In addition, neither indomethacin nor NG-nitro-L-arginine methyl ester affected the roxatidine-induced increases in mucus secretion and synthesis. We conclude that roxatidine directly acts on gastric mucosal cells, inducing increases in both the secretion and synthesis of mucus, and that an unknown regulatory pathway might be involved in these stimulatory actions of roxatidine.

Protein kinase C activation in the heart: effects on calcium and contractile proteins

BACKGROUND

Cardiac contractile function is dependent on the energetic state of the heart, intracellular calcium levels, and the interaction of the contractile proteins with both adenosine triphosphate and calcium. Protein kinase C (PKC) is a ubiquitous intracellular mediator that has been found in the heart and has been shown to phosphorylate proteins that regulate calcium homeostasis (calcium channels) and the contractile proteins themselves (troponin I and troponin T).

METHODS

To determine the role of PKC activation on cardiac contractile function, direct activation of PKC was achieved by the infusion of phorbol 12-myristate 13-acetate, an activating phorbol ester. The effects of PKC activation were evaluated in Langendorff-perfused rabbit hearts. Contractile function, high-energy phosphate content (phosphorous-31 nuclear magnetic resonance spectroscopy), oxygen consumption, and intracellular calcium levels (calcium fluorescent dye Rhod-2) were determined.

RESULTS

Activation of PKC in the heart by phorbol 12-myristate 13-acetate resulted in a significant decrease in both systolic and diastolic function while oxygen consumption and adenosine triphosphate production remained unchanged. Both baseline and peak intracellular calcium levels decreased, which may contribute to the impaired systolic function.

CONCLUSIONS

Activation of PKC in the heart leads to significant loss of contractile function without affecting energetics. The effect is most likely due to alteration in cytosolic calcium regulation and altered contractile sensitivity to calcium.

Multiple neuroepithelial tumors of different cell types--case report

A 31-year-old male developed intramedullary tumors in the medulla oblongata and the upper cervical spinal cord. He was first admitted with tetraparesis. Magnetic resonance (MR) imaging revealed a low intensity mass lesion in the medulla oblongata. The tumor was removed and diagnosed as a pilocytic astrocytoma. Nine years later, he was readmitted with motor weakness and dysesthesia in the right arm. MR imaging revealed a mass lesion in the cervical cord. This tumor was removed and diagnosed histologically as ependymoma. We suggest that the displacement of primitive spongioblasts with subsequent differentiation resulted in an astrocytoma and an ependymoma in adjacent areas.

Reaction of cytochrome bo3 with oxygen: extra redox center(s) are present in the protein

The reaction of oxygen with cytochrome bo3, a quinol oxidase from Escherichia coli, has been studied by resonance Raman scattering after initiation of the reaction by CO photolysis in a continuous flow apparatus and by directly mixing the enzyme with oxygen. The high-frequency region of the spectrum was monitored to determine the time evolution of the spin, oxidation, and coordination states of heme O and the oxidation state of heme B by using newly established marker lines for each heme. Three phases of the reaction were detected. In phase I, complete in 75 microseconds, O2 reacted with heme O and formed a low-spin ferric or ferryl adduct without significant oxidation of heme B. In phase II, between 75 and 120 microseconds, a small fraction of heme B was oxidized. In phase III, at approximately 1 s, the majority of heme B was oxidized and heme O reverted to a high-spin ferric state. The high rate of oxygen reduction at heme O to the three- or four-electron reduced level, despite a very low rate of heme B oxidation, indicates that there are electron donors active in the enzyme other than the metal centers. Assays of our enzyme preparations rule out a quinol in the tight binding (QH) site as a possible donor but instead suggest electron donation from the protein matrix, such as from tryptophans or tyrosine.(ABSTRACT TRUNCATED AT 250 WORDS)

Localization of furin to the trans-Golgi network and recycling from the cell surface involves Ser and Tyr residues within the cytoplasmic domain

Furin is a membrane-associated endoprotease that catalyzes cleavage of precursor proteins at Arg-X-Lys/Arg-Arg sites. Although, at steady state, furin is predominantly found in the trans-Golgi network (TGN), it also cycles between the TGN and the cell surface. Recently, the cytoplasmic tail of furin has been shown to be sufficient for its localization to the TGN. Within the cytoplasmic domain, there are Ser residues, which we now show are sites for phosphorylation by casein kinase II in vitro, and a Tyr-containing sequence, both of which have been shown to be important for other TGN proteins to localize to this compartment. In the present study, we show by site-directed mutagenesis that these residues are important for TGN localization and recycling of furin. Mutation of the Ser residues abrogated the TGN localization. By contrast, mutation of the Tyr residue did not affect the TGN localization but impaired the internalization from the plasma membrane. These observations suggest that distinct cytoplasmic determinants are responsible for retention in the TGN and retrieval from the cell surface of furin.

Chromosomal anomalies in prostatic intraepithelial neoplasia and carcinoma detected by fluorescence in situ hybridization

The pathogenetic relationship between high-grade prostatic intraepithelial neoplasia (PIN), prostatic carcinoma, and metastases is poorly understood. We used fluorescence in situ hybridization (FISH) with centromere-specific probes for chromosomes 7, 8, 10, 12, and Y to evaluate numeric chromosomal anomalies in PIN (68 foci), localized prostatic carcinoma (78 foci), and lymph node metastases (8 foci) in 40 whole-mount radical prostatectomy and pelvic lymphadenectomy specimens. Chromosomal anomalies were found in 50, 51, and 100% of the foci of PIN, carcinoma, and metastases, respectively. The mean numbers of abnormal chromosomes per focus were 0.66 in PIN, 1.09 in carcinoma, and 3.75 in metastases. The most frequent anomaly in PIN was a gain of chromosome 8 (32% of foci), followed by gains of chromosomes 10 (13%), 7 (10%), 12 (4%), and Y (4%). The most frequent anomalies in foci of carcinoma were gains of chromosomes 7 and 8 (28% and 30% of foci, respectively), followed by gains of chromosomes 10 (23%), 12 (9%), and Y (9%). There was a positive correlation of the gain of chromosome 8 with the pathological stage and Gleason score (both P < 0.05). Usually, carcinoma foci contained more anomalies than paired PIN foci, but five prostates contained one or more foci of PIN with more anomalies than carcinoma. Among the cases with metastases, usually one or more foci of the primary tumor shared chromosomal anomalies with the matched metastases. Our results indicate that PIN and prostatic carcinoma foci have similar proportions of chromosomal anomalies, but foci of carcinoma usually have more alterations. This observation supports the hypothesis that PIN is often a precursor of carcinoma, although there are some carcinoma foci that have few or no apparent chromosomal alterations, whereas concurrent PIN foci have multiple alterations. A gain of chromosome 8 was the most common numerical alteration and was associated with increasing cancer stage and grade, suggesting that it may play a role in the initiation and progression of prostatic carcinoma. Usually, one or more foci of the primary tumor shared chromosomal anomalies with associated lymph node metastases, suggesting that, often, just a single focus of carcinoma gives rise to metastases.

A second mutant allele of furin in the processing-incompetent cell line, LoVo. Evidence for involvement of the homo B domain in autocatalytic activation

Furin is a Golgi membrane-associated endoprotease that is involved in cleavage of various precursor proteins predominantly at Arg-X-Lys/Arg-Arg sites. Furin itself is synthesized as an inactive precursor, which is activated through intramolecular autocatalytic cleavage at an Arg-X-Lys-Arg site. We previously found that human colon carcinoma LoVo cells have a frameshift mutation within the homo B domain of furin and thereby lack processing activity toward Arg-X-Lys/Arg-Arg sites. In this study, however, we identified a second furin mutation in this cell line. The mutation, a replacement of a conserved Trp residue within the homo B domain with Arg, results in lack of processing activity of the mutant furin. The combination of both mutations can account for the recessive nature of the processing incompetence of LoVo cells. Immunofluorescence analysis with three distinct anti-furin monoclonal antibodies revealed that neither furin mutant underwent the autocatalytic activation or left the endoplasmic reticulum for the Golgi. These data indicate that the homo B domain as well as the catalytic domain is required for autocatalytic activation of furin.

Multisegmental anomaly of the inferior vena cava with thrombosis of the left inferior vena cava

We present a rare case of an extensive venous thrombosis associated with a multisegmental anomaly of the inferior vena cava (IVC), double IVCs, a hypoplastic right IVC, an aneurysm arising at the distal portion of the right IVC, and a severe stenosis between the prerenal and the hepatic segments of the IVC.

Volatile anaesthetic actions on norepinephrine-induced contraction of small splanchnic resistance arteries

The aim of this study was to investigate volatile anaesthetic action on small splanchnic resistance arteries. Employing isometric tension recording, we studied the effects of clinically relevant concentrations (0.25-1.25 minimum alveolar concentration (MAC)) of isoflurane, sevoflurane and enflurane on contractions induced by norepinephrine (NE), a sympathetic neurotransmitter, in the rabbit small mesenteric artery. Rhythmic oscillations were observed in contractile responses to NE. Both isoflurane (> or = 0.25 MAC, 0.5% (approximately 0.11 mM)) and sevoflurane (> or = 0.75 MAC, 2.8% (approximately 0.38 mM)) inhibited the NE (10 microM)-induced contraction with concomitant inhibition of average amplitude of the oscillations. Only enflurane (> or = 0.25 MAC, 0.7% (approximately 0.20 mM)) generated vasoconstriction superimposed on the NE-induced contraction; however, the vasoconstriction was transient and was followed by vasorelaxation. Concurrently, enflurane (> or = 0.25 MAC) strongly inhibited the average amplitude of the oscillations; higher concentrations (> or = 1.0 MAC) of enflurane completely eliminated the oscillations. The frequency of the NE-induced oscillations was less affected by the anaesthetics. The observed vasodilator action of these anaesthetics in small resistance arteries may contribute to their hypotensive effects in vivo. The potent inhibition of the rhythmic oscillations also may play a role in volatile anaesthetic-induced alterations in cardiovascular homeostasis.

Coronary artery spasm induced under lumbar epidural anaesthesia

A case of coronary artery spasm during lumbar epidural anaesthesia prior to surgery is presented. Three paroxysmal episodes of ST segment elevation in lead II without changes in V5 developed concomitantly when the patient complained of chest discomfort. A denervation of the cardiac sympathetic nerve seems to be the primary genesis of the attack in a patient prone to such events.

Liver scarring associated with congenital absence of the right hepatic lobe: CT and MR findings

We describe a patient with liver scarring associated with congenital absence of the right lobe of the liver. Computed tomography demonstrated a low density zone at the periphery of the liver that appeared hyperintense on T2-weighted MRI and markedly enhanced on contrast-enhanced T1-weighted imaging. Computed tomography during both arteriography and arterial portography demonstrated a differential blood supply to the low density zone, suggesting the diagnosis of liver scarring. Histological examination of a biopsy from this region disclosed periportal fibrosis and sinusoidal dilatation, confirming the diagnosis of liver scarring.

Ictal HMPAO-single photon emission computed tomography findings in reading epilepsy in a Japanese boy

Reading epilepsy is rare. We report a 14-year-old right-handed Japanese boy who had had jaw jerking only while reading since age 12 years. The episodes occurred every time he read an English textbook and sometimes during prolonged reading of a Japanese textbook. The jaw jerking evolved to generalized tonic-clonic seizures (GTCS) on only two occasions during prolonged reading aloud. Routine EEGs showed no abnormality. After a few minutes of reading, however, the EEG showed bilateral 2-Hz, 150-microV spike-wave complexes with left frontotemporal accentuation, accompanied by jaw jerking. Ictal single photon emission computed tomography (SPECT) with [99Tc]hexamethylpropylene amine oxime (HMPAO) showed focal hyperperfusion of the frontal lobes bilaterally and of the left temporal area. Interictal SPECT and magnetic resonance imaging (MRI) were normal. The combination of valproate (VPA) and clonazepam (CZP) almost eliminated his symptoms. Ictal SPECT is a useful technique for seizure localization in reading epilepsy.

Induction of plasminogen activator inhibitor type 1 in murine lupus-like glomerulonephritis

Three major components of the plasminogen activators (PA)/plasmin system are synthesized physiologically in glomeruli, and can be involved in glomerular proteolysis and extracellular matrix metabolism: tissue-type PA (tPA), urokinase (uPA) and PA inhibitor type 1 (PAI-1). To explore the possible role of a dysregulation of the plasmin protease system in the development and progression of lupus-like glomerulonephritis, we studied the expression of the renal plasmin protease components during the course of the disease, either acute, induced by IgG3 monoclonal cryoglobulins, or chronic, occurring spontaneously in three different lupus-prone mice: (NZBxNZW)F1, BXSB and MRL-lpr/lpr. RNase protection assays and in situ hybridizations revealed a marked glomerular induction of PAI-1 mRNA abundance without any significant changes in renal tPA and uPA mRNA levels in the two different types of lupus-like glomerulonephritis. The overexpression of PAI-1 mRNA occurred in parallel with a significant decrease in glomerular tPA-catalyzed enzymatic activity as determined by zymographic analysis. In addition, a concomitant increase in glomerular expression of transforming growth factor beta 1 (TGF-beta 1) mRNA was observed. The demonstration of a close correlation between the PAI-1 and TGF-beta 1 mRNA levels and the severity of lupus-like glomerular lesions suggests that a pertubation of the glomerular PA/PAI balance, resulting from a marked TGF-beta 1-mediated induction of PAI-1 gene expression, plays an important role in the progression of lupus-like glomerular lesions, leading to glomerulosclerosis.

Aberrant gastric venous drainage in cirrhotic livers: imaging findings in focal areas of liver parenchyma

PURPOSE

To analyze imaging finding in focal areas of liver parenchyma with aberrant gastric venous drainage (AGVD) in cirrhotic livers.

MATERIALS AND METHODS

Eighteen patients with AGVD confirmed with computed tomography (CT) during arterial portography and arteriography underwent ultrasound (US) (n = 18), CT (n = 18), magnetic resonance (MR) imaging (n = 12), dynamic CT (n = 14), and dynamic MR imaging (n = 8). Imaging and histologic (n = 2) findings were analyzed.

RESULTS

The focal area with AGVD was hypoechoic on US scans (n = 7), hypoattenuating on CT scans (n = 4), hyperintense on T1-weighted MR images (n = 6), and hypointense on T2-weighted MR images (n = 5). Early enhancement was seen with dynamic CT (n = 8) and with dynamic MR imaging (n = 6), without definite staining on arterial phase of arteriography. Histologic findings revealed hyperplastic changes of liver.

CONCLUSION

The imaging findings, except for early enhancement, were very similar to those of adenomatous hyperplasia or well-differentiated hepatocellular carcinoma. The early enhancement was considered due to early venous return compared with that of the surrounding liver.

A new enzymatic method for the determination of inulin

A new enzymatic method for the determination of inulin in plasma and urine, using inulase (EC 3.2.1.7), fructokinase (EC 2.7.1.4), phosphoglucoisomerase (EC 5.3.1.9) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) is described. The assay is based on the hydrolysis of inulin or Inutest (INutest which is the injectable form of inulin), by inulase and the determination of fructose released. The assay was linear up to 2 g/L of Inutest. The within-batch and between batch coefficients of variation were 2.3% and 2.2%, respectively. Recovery of added Inutest from plasma and urine was 98-102%. There was no interference from glucose (27.7 mmol/L), fructose (1.7 mmol/L) or mannose (1.7 mmol/L). When inulin clearance (using this method) and thiosulphate clearance were compared in 37 patients the inulin clearance was 9.3 mL/min (12%) lower than the thiosulphate clearance. We conclude that this enzymatic method is a simple and specific method.

Efficacy of simulated epidural test doses in adult patients anesthetized with isoflurane: a dose-response study

A recent study demonstrated that an epidural test dose containing 15 micrograms epinephrine was an imperfect marker for intravascular injection during isoflurane anesthesia based on the conventional heart rate (HR) criterion (positive if > or = 20 bpm increase). We have determined the effects of epinephrine doses and isoflurane concentrations on these efficacies in healthy adult patients during isoflurane anesthesia. Eighty patients were randomly assigned to one of four groups according to the simulated test dose injected intravenously (IV) under 1% end-tidal isoflurane and nitrous oxide after endotracheal intubation. The saline group (n = 20) received 3 mL normal saline; the epinephrine 7.5 group (n = 20) received 3 mL 1.5% lidocaine containing 7.5 micrograms epinephrine; the epinephrine 15 and epinephrine 22.5 groups (n = 20 each) received an identical dose and volume of lidocaine but containing 15 and 22.5 micrograms epinephrine, respectively. HR and systolic blood pressure (SBP) were monitored invasively for 4 min after IV injection of the study drug. Although none in the saline group developed a HR increase > or = 20 bpm, 2, 14, and 12 patients elicited positive responses in the epinephrine 7.5, 15, and 22.5 groups (10%, 70%, and 60% sensitivities), respectively. If a positive HR response was defined by an increase of 10 bpm, sensitivities were 55%, 100%, and 100% in the epinephrine 7.5, 15, and 22.5 groups, respectively. On the other hand, none in the saline group, 12 in the epinephrine 7.5 group, and all patients in the epinephrine 15 and 22.5 groups developed maximum SBP increases > or = 15 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of midazolam on intracellular Ca2+ and tension in airway smooth muscles

BACKGROUND

It has been demonstrated that a group of minor tranquilizers, benzodiazepines, are able to relax airway smooth muscles. To determine the underlying mechanisms of this phenomenon, the effects of midazolam on the intracellular Ca2+ concentration ([Ca2+]i) and tension in airway smooth muscles were investigated.

METHODS

Using front-surface fluorometry and fura-2-loaded porcine tracheal smooth muscle strips, both [Ca2+]i and isometric tension developments were simultaneously recorded.

RESULTS

When the tracheal strips were exposed to a high external K(+)-solution (40 mM) or 10(-7) M carbachol containing 1.25 mM Ca2+, both [Ca2+]i and tension increased rapidly until they reached a plateau (the steady state). During steady-state contraction induced by K(+)-depolarization or carbachol, the cumulative application of midazolam (10(-7) approximately 10(-4) M) caused decreases in both [Ca2+]i and tension, in a concentration-dependent manner. During 40 mM K(+)-induced depolarization, the stepwise increases in the extracellular Ca2+ concentration induced the stepwise increases in [Ca2+]i and tension. Midazolam (3 x 10(-5) M) inhibited these increases in [Ca2+]i and tension, but had no effect on the [Ca2+]i-tension relationship. In the presence of 3 x 10(-3) M NiCl2 (a nonselective cation channel blocker), midazolam (3 x 10(-5) M) did not cause any additional reduction of [Ca2+]i or tension during the contraction induced by carbachol (10(-7) M). In the absence of extracellular Ca2+, midazolam (3 x 10(-5) M) had no effect on the transient increases in either [Ca2+]i or the tension induced by carbachol (10(-7) M) or caffeine (20 mM). Pretreatment with both 10(-5) M flumazenil (a specific central antagonist of benzodiazepines) and 10(-5) M PK11195 (a specific peripheral antagonist of benzodiazepines) did not influence the effect of 10(-5) M midazolam on [Ca2+]i or tension during the contractions induced by carbachol.

CONCLUSIONS

Midazolam directly relaxes airway smooth muscles by decreasing [Ca2+]i; this can be attributed to the inhibition of the influx of extracellular Ca2+. Midazolam has no effect on the release of stored Ca2+. In addition, midazolam has no effect on Ca2+ sensitivity of the contractile apparatus. Finally, benzodiazepine antagonists, flumazenil and PK11195, have no effect on this mechanism of direct action of midazolam on airway smooth muscles.

[Ruptured mycotic aneurysm of the middle cerebral artery: a case report]

A sixty-two-year-old woman was diagnosed as having the mitral valve insufficiency seven months prior to admission. The patient was admitted to the hospital with complaints of right hemiparesis and aphasia. CT scan revealed an intracerebral hematoma in the left front-parietal region. Cerebral angiography disclosed an aneurysm at the distal portion of left middle cerebral artery. An increase in the amount of C reactive protein and leukocytosis indicated the presence of inflammatory lesions. Antibiotics were administered because a mycotic aneurysm was suspected. White blood cell count and C reactive protein returned to normal after treatment with antibiotics for one months. The aneurysm had disappeared on the second angiography performed after treatment. Strategy for mycotic aneurysm is still controversial. 49 reported cases in the literature since 1975 were reviewed and the efficiency of antibiotic therapy was discussed.

Regulation of neutral cholesterol esterase activity by phospholipids containing negative charges in substrate liposome

The effect of phospholipids on cholesteryl ester hydrolysis by neutral cholesterol esterase in alveolar macrophages was studied. Among the phospholipids used as emulsifiers, those with a negative charge, such as phosphatidylserine, phosphatidic acid, phosphatidylinositol, and cardiolipin, gave a higher level of hydrolysis by neutral cholesterol esterase than other less negatively charged phospholipids, such as phosphatidylcholine, lysophosphatidylcholine, phosphatidylethanolamine, and sphingomyelin. Phospholipase D treatment of liposomes emulsified with phosphatidylcholine produced phosphatidic acid and enhanced cholesteryl ester hydrolysis. Phospholipase A2 treatment produced lysophosphatidylcholine and decreased the hydrolysis. The hydrolysis of cholesteryl ester in lipid droplets obtained from cholesterol-laden macrophages elicited by thioglycollate in the rat peritoneal cavity was low compared to artificial liposomes emulsified with phosphatidylcholine. The reason for this was speculated to be that lipid droplets were low in total phospholipids and poor in phospholipids with strong negative charges but rich in phosphatidylethanolamine and sphingomyelin. These results suggest that the polar heads of phospholipids may play an important role in cholesteryl ester hydrolysis by neutral cholesterolesterase.

Selective depletion of cyclin-dependent kinases is associated with Fas-mediated apoptosis in human leukemia T-cell lines

The Fas/Apo-1 molecule is a member of tumor necrosis factor/nerve growth factor (TNF/NGF) receptor family and is able to induce apoptosis in various type of malignant cells, including most of the human leukemia T-cells. We previously demonstrated that the Fas-resistant variants may exist in highly Fas-sensitive human leukemia T-cell lines. The surface expression of Fas antigen was unchanged in the variant cells, suggesting the requirement of the cytoplasmic mechanism to exert apoptosis. In the present study, we examined the changes in cytoplasmic proteins of the Fas-sensitive and Fas-resistant cells after stimulation with anti-Fas antibody, 2D1. In Western blotting analysis, we found that the stimulation of Fas-sensitive cells with 2D1, but not resistant variants, induced a repression of cyclin-dependent kinases (cdks), p34cdc2 and p33cdk2, along with apoptosis. There was no alteration in the expression of bcl-2, HSP70, HSP90, and cyclin proteins examined. This observation seemed specific to Fas-mediated apoptosis, because calcium ionophore A23187 or sodium azide failed to repress the expression of cdks. These results indicate that the specific depletion of cdks, most likely due to proteolysis, may play a role in Fas-mediated apoptosis.