Electrocardiographic changes related to parasympathetic tone during right coronary angioplasty

The role of basal parasympathetic tone in reducing the heart rate and causing electrocardiographic (ECG) changes during right coronary angioplasty was evaluated in 19 patients with angina pectoris. To measure parasympathetic tone, time and frequency domain parameters of heart rate variability were assessed using 24 h of ambulatory ECG data recorded before angioplasty. There was an age-dependent reduction in heart rate. However, no parameters of heart rate variability were responsible for the changes in heart rate. In contrast, the degree of ST segment elevation during angioplasty correlated significantly with the high-frequency component of heart rate variability. Therefore, the increased parasympathetic tone, as assessed by spectral analysis, may augment the early ST segment elevation induced by right coronary occlusion.

Inhibited serum phospholipase A2 activity in hyperbilirubinemia

BACKGROUND/AIMS

Phospholipase A2 activity is reported to be related to the physiology of various disorders, and the activity is modified by deoxycholic acid.

METHODOLOGY

Serum phospholipase A2 activity was measured by counting the radioactivity of 14C-palmitic acid released from L-3-phosphatidylcholine (1-palmitoyl-2-14C-palmitoyl) in 40 patients with hyperbilirubinemia due to malignant neoplasms and benign cholestasis. Phospholipase A2 activity in serum from healthy subjects was also measured after incubation with 5-30 mg of bilirubin per dL or 0.1-5 mM of cholic acid for 60 min at 37 degrees C.

RESULTS

Serum phospholipase A2 activity was significantly lower in patients with hyperbilirubinemia. There were negative correlations between serum phospholipase A2 activity and concentration of total bilirubin (r = 0.668; P < 0.0001) or total bile acids (r = 0.423; P < 0.05) in patients with hyperbilirubinemia. In 12 patients who underwent percutaneous transhepatic biliary drainage, the low serum phospholipase A2 activity was reversed while bilirubin concentrations decreased. Incubation of sera from healthy subjects with more than 3 mM cholic acid significantly reduced phospholipase A2 activity (P < 0.01), whereas incubation with bilirubin had no effect.

CONCLUSIONS

Inhibition of serum phospholipase A2 activity in patients with hyperbilirubinemia may be caused by increased serum cholic acid concentration.

Discovery of novel trans-3,5-disubstituted pyrrolidinylthio-1beta-methylcarbapenems

Novel trans-3,5-disubstituted pyrrolidinylthio-1beta-methylcarbapenems were designed and synthesized to provide J-111,347 (1a) as the first example of an exceptionally broad-spectrum antibiotic, showing activity against methicillin-resistant Staphyloccocus aureus (MRSA) as well as Pseudomonas aeruginosa. Further derivation of 1a afforded J-111,225 (2a), J-114,870 (3a), and J-114,871 (3b). which showed improved safety profiles and retained broad-spectrum antibacterial activities.

Afferent mechanisms of acute responses of renal sympathetic nerve activity to microgravity

Exposure to microgravity is thought to induce an alteration of autonomic function through several afferent pathways. First, a removal of all hydrostatic gradients, which results in a large cephalad fluid shift. The fluid shift may induce an increase in transmural pressure in the cardiopulmonary region, which stimulates cardiopulmonary mechanoreceptors and baroreceptors, and elicits neurogenic responses. Secondly, an alteration of the vestibular input may modify sympathetic output via the vestibulosympathetic reflex. However, there is a lack of direct evidence for the role of cardiopulmonary mechanoreceptors, baroreceptors, and vestibular system in autonomic responses to microgravity. Accordingly, responses of renal sympathetic nerve activity (RNA) to microgravity, produced by free drop, were examined in anesthetized rats. To examine the afferent pathways of the RNA responses, the same experiment was performed in rats that had undergone labyrinthectomy, sinoaortic baroreceptor denervation (SAD), vagotomy, or SAD plus vagotomy.

Acute responses of renal nerve activity to microgravity induced by free drop in anesthetized rats

To examine acute cardiovascular and autonomic responses to microgravity (microG), arterial pressure (AP), aortic flow velocity (AFV), central venous pressure (CVP), and renal nerve activity (RNA) were measured in anesthetized rats during 4.5 s of microG produced by free drop. A smooth and immediate reduction in gravity occurred during free drop, microG being achieved 100 ms after the start of the drop. Acute microG elicited an immediate and striking, but transient, decrease in RNA with no significant change in AP and AFV, but a significant decrease in CVP. The decrease in RNA lasted 2 s, then RNA recovered to the control level despite the G value remaining at < 0.001 for 4.5 s. The RNA decrease was attenuated or completely abolished by sinoaortic denervation, vagotomy, or sinoaortic denervation plus vagotomy. These results suggest that acute microG conditions stimulate sinoaortic and cardiopulmonary mechanoreceptors and suppress RNA.

The roles of platelet-activating factor and endothelin-1 in renal damage after total hepatic ischemia and reperfusion

BACKGROUND

This study was designed to verify the involvement of platelet-activating factor (PAF) in renal damage associated with hepatic ischemia and reperfusion (HIR) injury through the release of endothelin (ET)-1 and to determine the modulating effect of a specific PAF receptor antagonist on these insults in rats.

METHODS

Male rats pretreated with either normal saline as a vehicle (NS group) or intravenous TCV-309, a PAF receptor antagonist (TCV group), were subjected to 120 min of total hepatic ischemia under an extracorporeal portosystemic shunt. Plasma aspartate transaminase, creatinine, blood urea nitrogen, and ET-1 levels and the relative renal wet weight were determined under nonischemic conditions and at 1, 3, and 6 hr of reperfusion after hepatic ischemia. Changes in mean arterial blood pressure and renal tissue blood flow measurements in the kidney were determined throughout the experiment.

RESULTS

Increased plasma aspartate transaminase, creatinine, blood urea nitrogen, and ET-1 levels and the relative renal wet weight after HIR in the NS group were significantly suppressed by TCV-309 pretreatment. Mean arterial blood pressure and renal tissue blood flow after HIR in the TCV group were significantly improved when compared with those in the NS group. These effects resulted in attenuation of structural hepatic and renal damage with the improvement of 7-day survival (62%).

CONCLUSIONS

The present study demonstrates that renal damage as well as critical liver injury is produced after reperfusion following 120 min of total hepatic ischemia. A PAF receptor antagonist may be therapeutically useful to protect against these types of damage via indirect modulation of plasma ET-1 levels.

Role of the vestibular system in sudden shutdown of renal sympathetic nerve activity during microgravity in rats

The purpose of this study was to examine the effect of microgravity (muG) on renal sympathetic nerve activity (RNA) in rats. Additionally, we estimated the participation of the vestibular system in the response of RNA to muG. Eight normal Sprague-Dawley (SD) rats and five chemically and bilaterally labyrinthectomied SD rats were used to measure RNA during free-drop examination (4.5-s duration of muG); arterial pressure (AP) and aortic flow velocity (AFV) were additionally monitored. Although AFV showed no particular change, AP tended to decrease during muG in the later phase. Prior to this AP fall-off, RNA was immediately and markedly attenuated by muG. This attenuation was transient and RNA returned to 1G level within the mu;muG condition. Interestingly, this phenomenon remained even in labyrinthectomied rats. In conclusion, cephalad shift of the body fluid by loading of muG may cause cardiopulmonary low-pressure receptor activation and consequent RNA attenuation, but the participation of the vestibulosympathetic reflex in this phenomenon is not obvious.

Thyroid hypertrophic effect of semotiadil fumarate, a new calcium antagonist, in rats

We studied the effects of semotiadil fumarate (SF), a new calcium antagonist with a unique benzothiazine structure, on the thyroid gland and liver in rats and compared them with those of another calcium antagonist, nicardipine (NCD), a well-known thyroidal hypertrophic agent and microsomal enzyme inducer, phenobarbital (PB), and goitrogen propylthiouracil (PTU). In oral 2-week treatment, SF caused increases in hepatic microsomal protein levels, uridine diphosphate glucuronosyltransferase (UDPGT) activity and an increase in serum thyroid stimulating hormone (TSH) level together with decreases in serum thyroid hormone levels. These results suggest that SF accelerates peripheral disposition of thyroid hormones and subsequently stimulates secretion of TSH from the pituitary gland as a compensatory response. PB and NCD had similar effects on the thyroid gland and the liver. PTU showed obvious thyroid hyperplasia and an increase in relative liver weight. Drastic increase in TSH level was observed in the PTU-treated group together with significant decreases in serum thyroid hormone levels and an increase in hepatic UDPGT activity. Histopathologically, PTU depleted the colloids in follicles, suggesting the inhibition of thyroid hormone synthesis. SF, PB and NCD showed thyroidal hyperplasia, but the extent of the change was far more moderate than that induced by PTU. These results indicate that the effect of SF is similar to those of PB and thyroid hypertrophy seen in the oral 2-week treatment with SF, and may be caused by indirectly elevated TSH levels which resulted from the induction of hepatic UDPGT activity.

The role of ABI3 and FUS3 loci in Arabidopsis thaliana on phase transition from late embryo development to germination

Arabidopsis abi3 and fus3 mutants are defective in late embryo development and their embryos show precocious growth. To understand the function and role of ABI3 and FUS3, we analyzed expression patterns of genes which were normally activated during late embryo development and germination in these mutants. Using the differential display method, both upregulated and downregulated genes were observed in immature siliques of the abi3 fus3 double mutant. Four clones having more abundant expression in the abi3 fus3 double mutant than in wild type were isolated. These genes were activated during wild-type germination, suggesting that some genes that are activated during wild-type germination are precociously activated in the abi3 fus3 mutant during late embryo development. Also, genes that were activated during wild-type germination were isolated and their expression patterns during late embryo development in the wild type and in abi3, fus3, and abi3 fus3 mutants were analyzed. Sixteen such clones were found, and 11 of these showed derepression or precocious activation of gene expression in the mutants. These results indicate that ABI3 and FUS3 negatively regulate a particular set of genes during late embryo development. We also showed that immature fus3 siliques accumulated one-third of the wild-type level of abscisic acid (ABA), but mature fus3 siliques accumulated ABA at a level comparable to that in the wild type. The possible mechanisms of controlling developmental timing in late embryo development as well as collaborative and distinct roles of ABI3 and FUS3 are discussed.

[A patient with advanced gastric cancer who obtained downstaging and underwent radical surgery by neoadjuvant chemotherapy]

The patient was a 74-year-old man with extremely advanced gastric cancer. A CT scan of the abdomen showed enlargement of many huge abdominal para-aortic lymph nodes. Neoadjuvant chemotherapy (NAC) was planned in order to reduce or eliminate the tumor. Two cycles of FLP combination therapy (5-fluorouracil, leucovorin, cisplatin) were given. After NAC, a CT scan revealed marked shrinkage of the No. 16 lymph nodes, and a distal gastrectomy with extended radical lymph node dissection including the No. 16 nodes was performed. The histological effect was judged to be grade 2. There were no viable cancer cells in the No. 16 lymph nodes. The FLP combination therapy as NAC was so effective that it induced downstaging from stage IVb to IIIb.

[The three-dimensional CT angiography findings of ruptured aneurysms hardly detectable by repeated cerebral angiography]

We reported three cases of cerebral aneurysms hardly detectable by cerebral angiography, but easily detected by three-dimensional CT angiography (3D-CTA). These cases were ruptured aneurysms with subarachnoid hemorrhage. After detection of subarachnoid hemorrhage on CT scan, cerebral angiography was performed at first, but aneurysms were not detected. Subsequently 3D-CTA was carried out, and aneurysms were detected. In all cases, cerebral angiography was repeated, after the aneurysms had been found by 3D-CTA. This time aneurysms were all detected by cerebral angiography, but each case needed photographs from special direction. The aneurysms were small by usual cerebral angiography and they were almost invisible behind the artery near which they existed. 3D-CTA was very useful for detection of small aneurysms, but small perforating arteries around the aneurysms were invisible by 3D-CTA. To find these perforating arteries, cerebral angiography was needed.

Studies on the 1,1-diphenyl-2-picrylhydrazyl radical scavenging mechanism for a 2-pyrone compound

The radical scavenging mechanisms for the 2-pyrone compound, 4-hydroxy-3,6-dimethyl-2H-pyrane-2-one (1), and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical (4) in several solvent systems were evaluated by the quantitative change in compounds detected at 270 nm and subsequent HPLC analyses. The HPLC profile for each condition suggested that the reaction proceeded by a different mechanism in each solvent system. In organic solvents (CHCl3, iso-propanol, and EtOH), 1-[4-(3,4-dihydro-3,6-dimethyl-2,4-dioxo-2H-pyran-3-yl) phenyl]-1-phenyl-2-picrylhydrazine (2) was produced as an adduct of the DPPH radical and 1. On the other hand, the reaction in a buffer solution (an acetate buffer at pH 5.5) gave several degradation products with 1[4-(2,3-dihydro-2,5-dimethyl-3-oxo-fur-2-yl) phenyl]-1-phenyl-2-picrylhydrazine (5), this being structurally elucidated by spectroscopic analyses. The decrease of the DPPH radical in each reaction system suggests that compound 1 could scavenge about 1.5-1.8 equivalents of the radical in organic solvents and about 3.5-3.9 in the buffer solution.

Deep venous thrombosis and pulmonary thromboembolism associated with a huge uterine myoma--a case report

A 51-year-old woman with a large uterine myoma suffered from acute pulmonary thromboembolism. Venography revealed thrombosis in the right common iliac vein and almost complete obstruction of the left common iliac vein. The ascending lumbar vein showed collateral drainage. Treatment was initiated with continuous intravenous heparin sodium, and a Greenfield filter was inserted to prevent the extension of the pulmonary embolism during and after hysterectomy. After a total hysterectomy, venography revealed restoration of patency in the bilateral common iliac veins, and no flow was seen in the ascending lumbar vein. Thorough clinical examinations failed to identify any other prothrombotic conditions. These results suggest that a large uterine myoma compressed veins in the pelvis, and the resulting impaired blood flow caused deep venous thrombosis and pulmonary thromboembolism.

Effects of chlorine, iodine, and quaternary ammonium compound disinfectants on several exotic disease viruses

The effects of three representative disinfectants, chlorine (sodium hypochlorite), iodine (potassium tetraglicine triiodide), and quaternary ammonium compound (didecyldimethylammonium chloride), on several exotic disease viruses were examined. The viruses used were four enveloped viruses (vesicular stomatitis virus, African swine fever virus, equine viral arteritis virus, and porcine reproductive and respiratory syndrome virus) and two non-enveloped viruses (swine vesicular disease virus (SVDV) and African horse sickness virus (AHSV)). Chlorine was effective against all viruses except SVDV at concentrations of 0.03% to 0.0075%, and a dose response was observed. Iodine was very effective against all viruses at concentrations of 0.015% to 0.0075%, but a dose response was not observed. Quaternary ammonium compound was very effective in low concentration of 0.003% against four enveloped viruses and AHSV, but it was only effective against SVDV with 0.05% NaOH. Electron microscopic observation revealed the probable mechanism of each disinfectant. Chlorine caused complete degeneration of the viral particles and also destroyed the nucleic acid of the viruses. Iodine destroyed mainly the inner components including nucleic acid of the viruses. Quaternary ammonium compound induced detachment of the envelope of the enveloped viruses and formation of micelle in non-enveloped viruses. According to these results, chlorine and iodine disinfectants were quite effective against most of the viruses used at adequately high concentration. The effective concentration of quaternary ammonium compound was the lowest among the disinfectants examined.

The novel neuropeptide Y Y(1) receptor antagonist J-104870: a potent feeding suppressant with oral bioavailability

Neuropeptide Y (NPY) is known to induce robust feeding through the action of NPY receptors in the hypothalamus. Among the subtypes of NPY receptors, Y(1) receptors may play a key role in feeding regulation. In the present study, we demonstrated that a novel Y(1) antagonist, J-104870, shows high selectivity and potency for the Y(1) receptor with an anorexigenic effect on NPY-mediated feeding. J-104870 displaced [(125)I]peptide YY (PYY) binding to cloned human and rat Y(1) receptors with K(i) values of 0.29 and 0.54 nM, respectively, and inhibited the NPY (10 nM)-induced increase in intracellular calcium levels (IC(50) = 3.2 nM) in cells expressing human Y(1) receptors. In contrast, J-104870 showed low affinities for human Y(2) (K(i) > 10 microM), Y(4) (K(i) > 10 microM), and Y(5) receptors (K(i) = 6 microM). In rat hypothalamic membranes, J-104870 also completely displaced the binding of [(125)I]1229U91, which is known to bind to the typical Y(1) receptor, with a high affinity (K(i) = 2.0 nM). Intracerebroventricular (ICV) injection of J-104870 (200 microg) significantly suppressed NPY (5 microg)-induced feeding in satiated Sprague-Dawley rats by 74%. Furthermore, ICV and oral administration of J-104870 (200 microg and 100 mg/kg, respectively) significantly suppressed spontaneous food intake in Zucker fatty rats. These findings suggested that J-104870 is a selective and potent nonpeptide Y(1) antagonist with oral bioavailability and brain penetrability. In addition, the anorexigenic effect of J-104870 clearly revealed the participation of the Y(1) receptor in NPY-mediated feeding regulation. The potent and orally active Y(1) antagonist J-104970 is a useful tool for elucidating the physiological roles of NPY in obesity.

J-104129, a novel muscarinic M3 receptor antagonist with high selectivity for M3 over M2 receptors

A new class of 4-acetamidopiperidine derivatives has been synthesized and investigated for human muscarinic receptor subtype selectivity. Introduction of a hydrocarbon chain of appropriate length into the piperidine nitrogen of the racemic N-(piperidin-4-yl)-2-cyclobutyl-2-hydroxy-2-phenylacetamide platform conferred up to 70-fold selectivity for human muscarinic M3 receptors over M2 receptors. Subsequent synthetic derivatizations resulted in highly potent M3 receptor antagonists with selectivity greater than two orders of magnitude for M3 over M2 receptors, from which the analogue 4r was selected. Preparation of both enantiomers of 4r led to the identification of (2R)-N-[1-(4-methyl-3-pentenyl)piperidin-4-yl]-2-cyclopentyl-2-hyd roxy-2-phenylacetamide (J-104129, (R)-4r), which exhibited 120-fold selectivity for M3 receptors (Ki = 4.2 nM) over M2 receptors (Ki = 490 nM). In isolated rat trachea, (R)-4r potently and specifically antagonized acetylcholine (ACh)-induced responses with a K(B) value of 3.3 nM. The highly subtype-selective profile was also seen in isolated rat tissue assays (50-fold) and in anesthetized rats (> 250-fold). Oral administration of J-104129 ((R)-4r) antagonized ACh-induced bronchoconstriction with an ED50 value of 0.58 mg/kg in rats. Thus, J-104129 ((R)-4r) may effectively facilitate bronchodilation in the treatment of obstructive airway disease.

[A case of advanced gastric cancer with abdominal para-aortic lymph node metastasis successfully treated with FLP therapy]

A 73-year-old woman was admitted to our hospital in June 1998, suffering from upper abdominal pain. The upper G-I series and endoscopic examination revealed stenosis of the pylorus and antrum by a type 2 cancer, and a poorly differentiated adenocarcinoma and a signet-ring cell carcinoma were confirmed on endoscopic biopsy. A CT scan showed the enlargement of many regional and abdominal para-aortic lymph nodes. FLP therapy combined with cisplatin (50 mg/m2 drip i.v., day 1-8), 5-fluorouracil (333 mg/m2 drip i.v.) and leucovorin (30 mg/body i.v., day 1-8) was planned for neoadjuvant chemotherapy (NAC) in order to reduce or eliminate the tumor and increase curability. After two cycles of the FLP therapy, the tumor size shrunk remarkably and the enlargement of the para-aortic lymph nodes disappeared. Distal gastrectomy with extended lymphadenectomy and cholecystectomy was performed. The histological findings of the primary tumor and metastatic lymph nodes demonstrated massive cancer cell degeneration such as pycnosis and vacuolation, xanthogranulomatous inflammation and dense fibrosis. The effect of NAC was judged to be grade 2 histologically. FLP therapy is an effective and safe regimen for NAC.

[Effects of intravenous and oral administration of ondansetron hydrochloride on chemotherapy-induced nausea and vomiting in patients with esophageal cancer]

The effects of ondansetron hydrochloride (OND) were studied through 11 courses of chemotherapy, including 70 mg/m2 of cisplatin, in 9 patients with advanced esophageal cancer. During the observation period of 5 days, 4 mg of OND was given intravenously on the day of cisplatin infusion and orally for consecutive 4 days, and nausea was controlled by over 70%. Vomiting was controlled by over 80%. The inhibitory effect of OND on nausea and vomiting was found in 72.7% on the day of cisplatin injection and 88.9% overall. No other side effects of OND except slight increases in total bilirubin and LDH were found in any patient. These findings suggest that intravenous and oral administration of OND may inhibit chemotherapy-induced nausea and vomiting in patients with advanced esophageal cancer.

Combined modality therapy for basaloid squamous carcinoma of the esophagus

A 61 year-old woman came to our hospital with dysphasia that had persisted for 2 months. Endoscopy and barium swallow showed a protruding tumor, about 6.0 cm long, in the midportion of the esophagus. A biopsy specimen showed squamous cell carcinoma of the esophagus. Computed tomography (CT) scan revealed adventitial involvement and lymph node metastases beneath the carina. After 2 courses of chemotherapy with cisplatin (CDDP) 100 mg for 1 day, 5-Fluorouracil (5-FU) 800 mg for 5 days, and leucovorin 30 mg for 5 days, complete regression of the tumor was observed by endoscopy and barium esophagography. Transthoracic esophagectomy with lymph node dissection was performed. Histologically, the muscle layers of the resected esophagus had been replaced by fibrous tissue; however, small foci of basaloid squamous carcinoma (BSC) were found in the submucosa. Six months after surgery, a CT scan revealed a metastatic lymph node around the right main bronchus. Chemotherapy and radiotherapy resulted in the disappearance of the metastasis. The patient has survived for more than 3 years since surgery with a good quality of life.

Double cancer of the gallbladder and common bile duct associated with an anomalous pancreaticobiliary ductal junction without a choledochal cyst: report of a case

We report herein the case of a 37-year-old woman found to have double cancer of the gallbladder and common bile duct associated with an anomalous pancreaticobiliary ductal junction (APBDJ) without a choledochal cyst (CC). Abdominal ultrasonography showed an isoechoic mass in the gallbladder, and percutaneous transhepatic biliary drainage tubography revealed incomplete obstruction in the upper portion of the common bile duct and APBDJ. The patient underwent cholecystectomy, partial hepatic resection, pancreatoduodenectomy, and portal vein reconstruction. Pathological examination of the tumors from the gallbladder and bile duct revealed papillary carcinoma and poorly differentiated adenocarcinoma, respectively, and direct continuity was not observed between the tumors. A review of the literature on six cases of multiple primary carcinoma of the biliary tract associated with APBDJ without CC is presented following this case report. Double cancer of the biliary tract was found synchronously in five patients and metachronously in one. Gallbladder cancer showed subserosal invasion in four patients, while bile duct cancer invaded the pancreas in one patient and reached the serosa in two patients. Considering the potential for cancer to arise in the biliary tract and the difficulties associated with monitoring it, cholecystectomy and resection of the extrahepatic common bile duct may be the most appropriate treatment for patients with an APBDJ without a CC.

Femtosecond time-resolved optical polarigraphy: imaging of the propagation dynamics of intense light in a medium

A time-resolved imaging technique for visualizing ultrafast propagation dynamics of intense light pulses in a medium has been demonstrated. The method probes the instantaneous birefringence induced by a pulse in the medium. Through consecutive femtosecond snapshot images of intense femtosecond laser pulses propagating in air, ultrafast temporal changes in the two-dimensional spatial distribution of the optical pulse intensity were clearly seen.

Purification and further characterization of enteropeptidase from porcine duodenum

Enteropeptidase [EC 3.4.21.9] is a membrane-bound serine endopeptidase present in the duodenum that converts trypsinogen to trypsin. We previously cloned the cDNA of the porcine enzyme and deduced its entire amino acid sequence [M. Matsushima et al. (1994) J. Biol. Chem. 269, 19976-19982]. In the present study, we purified the porcine enzyme approximately 2,200-fold in a 12% yield from a duodenal mucosal extract to apparent homogeneity by an improved procedure comprising four steps of chromatography including benzamidine-Sepharose affinity chromatography. Lectin blotting analysis suggested that the enzyme is glycosylated mainly with N-linked carbohydrate chains of the tri- and/or tetraantennary complex type. The H and L chains of the enzyme were separated into two major bands upon SDS-PAGE under reducing conditions, suggesting that the enzyme mainly comprises two isoforms, a higher molecular weight form and a lower molecular weight form. The enzyme was also separated by lectin affinity chromatography into two major fractions, named isoforms I and II, which corresponded to the higher and lower molecular weight forms, respectively. These two isoforms appeared to be different only in the carbohydrate moiety, having essentially the same enzymatic properties. The enzyme was optimally active at pH 8.0 toward Gly-Asp-Asp-Asp-Asp-Lys-beta-naphthylamide, and was inhibited strongly by various serine proteinase inhibitors. Furthermore, it was also strongly inhibited by E-64 [L-trans-epoxysuccinyl-leucylamide-(4-guanido)-butane], a cysteine proteinase inhibitor. Substrate specificity studies involving various synthetic peptides indicated that acidic residues at the P2, P3, and/or P4 positions are especially favorable for maximal activity, but are not absolutely necessary, at least in the cases of peptide substrates.

Electron microscopic autoradiography: an improved procedure using Aclar film and Grid-sticks

A simple, time saving technique for electron microscopic autoradiography (EMARG) has been developed using both Aclar film and Grid-sticks. Rats were given 3 mg/kg [pyridine5-3H] nicorandil orally. After 15 min, animals were sacrificed, the hearts were removed, and myocardial samples for EMARG were prepared. Silver grains were detected clearly in myofibrils and in mitochondria, all showing well preserved ultrastructure. The use of Grid-sticks in the procedure improves handling of bulk samples.