AKAPs as antiarrhythmic targets?

Phosphorylation of ion channels plays a critical role in the modulation and amplification of biophysical signals. Kinases and phosphatases have broad substrate recognition sequences. Therefore, the targeting of kinases and phosphatases to specific sites enhances the regulation of diverse signaling events. Ion channel macromolecular complexes can be formed by the association of A-kinase anchoring proteins (AKAPs) or other adaptor proteins directly with the channel. The discovery that leucine/isoleucine zippers play an important role in the recruitment of phosphorylation-modulatory proteins to certain ion channels has permitted the elucidation of specific ion channel macromolecular complexes. Disruption of signaling complexes by genetic defects can lead to abnormal physiological function. This chapter will focus on evidence supporting the concept that ion channel macromolecular complex formation plays an important role in regulating channel function in normal and diseased states. Moreover, we demonstrate that abnormal complex formation may directly lead to abnormal channel regulation by cellular signaling pathways, potentially leading to arrhythmogenesis and cardiac dysfunction.

Association of habitual long-distance running with the thickness of skeletal muscles and subcutaneous fat in the body extremities and trunk in middle-aged men

AIM

We investigated the association of habitual long-distance running with the thickness of skeletal muscles and subcutaneous fat in the body extremities and trunk in middle-aged men using ultrasonography.

METHODS

Three groups of healthy middle-aged men [mean (SD), 62.1 (2.8) years] took part in this investigation: a high-level group of 11 master runners who had competed in a 42.195 km race and run 51.6 (21.7) km every week, an intermediary-level group of 10 master runners who had competed in a 5-20 km race and run 9.3 (4.9) km every week, and a low-level group of 7 untrained men who continued to do no systematic training. The muscle thickness at 8 sites and the subcutaneous fat thickness at 10 sites were measured by B-mode ultrasonography, and were compared among the 3 groups.

RESULTS

The high-level group had 10.0(-1)5.2% higher values for muscle thickness at the erector spinae, hamstrings, tibialis anterior, and triceps surae, compared with the intermediary-level and the low-level groups (p<0.05-0.001). The thickness of the subcutaneous fat about the rectus abdominis and external oblique was lower in the high-level group than in the intermediary-level and the low-level groups (p<0.05).

CONCLUSIONS

Middle-aged male master athletes who habitually run at a high level have more muscle thickness in the lower extremities and trunk, and less subcutaneous fat thickness in the central regions of the body than do middle-aged men who habitually run at an intermediary level or do not run at all.

Stimulation of protein kinase C inhibits bursting in disease-linked mutant human cardiac sodium channels

BACKGROUND

Mutations in SCN5A, the gene coding for the human cardiac Na+ channel alpha-subunit, are associated with variant 3 of the long-QT syndrome (LQT-3). Several LQT-3 mutations promote a mode of Na+ channel gating in which a fraction of channels fail to inactivate, contributing sustained Na+ channel current (Isus), which can delay repolarization and prolong the QT interval. Here, we investigate the possibility that stimulation of protein kinase C (PKC) may modulate Isus, which is prominent in disease-related Na+ channel mutations.

METHODS AND RESULTS

We measured the effects of PKC stimulation on Na+ currents in human embryonic kidney (HEK 293) cells expressing 3 previously reported disease-associated Na+ channel mutations (Y1795C, Y1795H, and DeltaKPQ). We find that the PKC activator 1-oleoyl-2-acetyl-sn-glycerol (OAG) significantly reduced Isus in the mutant but not wild-type channels. The effect of OAG on Isus was reduced by the PKC inhibitor staurosporine (2.5 micromol/L), ablated by the mutation S1503A, and mimicked by the mutation S1503D. Isus recorded in myocytes isolated from mice expressing DeltaKPQ channels was similarly inhibited by OAG exposure or stimulation of alpha1-adrenergic receptors by phenylephrine. The actions of phenylephrine on Isus were blocked by the PKC inhibitor chelerythrine.

CONCLUSIONS

We conclude that stimulation of PKC inhibits channel bursting in disease-linked mutations via phosphorylation-induced alteration of the charge at residue 1503 of the Na+ channel alpha-subunit. Sympathetic nerve activity may contribute directly to suppression of mutant channel bursting via alpha-adrenergic receptor-mediated stimulation of PKC.

Leucine/isoleucine zipper coordination of ion channel macromolecular signaling complexes in the heart. Roles in inherited arrhythmias

The sympathetic nervous system controls the force and rate of contraction of the heart. The rapid response to stress and exercise mediated by increased sympathetic nervous system (SNS) activity requires the coordinated regulation of several ion channels in response to activation of beta-adrenergic receptors. The microenvironment of target channels is mediated by the assembly of macromolecular signaling complexes in which targeting proteins recruit phosphatases and kinases and in turn bind directly to the channel protein via highly conserved leucine/isoleucine zippers (LIZs). Disruption of local signaling by disease-associated LIZ mutations unbalances the physiologic response to SNS stimulation and increases the risk of arrhythmia in mutation carriers.

Clostridium thermocellum cellulase CelT, a family 9 endoglucanase without an Ig-like domain or family 3c carbohydrate-binding module

The celT gene of Clostridium thermocellum strain F1 was found downstream of the mannanase gene man26B [Kurokawa J et al. (2001) Biosci Biotechnol Biochem 65:548-554] in pKS305. The open reading frame of celT consists of 1,833 nucleotides encoding a protein of 611 amino acids with a predicted molecular weight of 68,510. The mature form of CelT consists of a family 9 cellulase domain and a dockerin domain responsible for cellulosome assembly, but lacks a family 3c carbohydrate-binding module (CBM) and an immunoglobulin (Ig)-like domain, which are often found with family 9 catalytic domains. CelT devoid of the dockerin domain (CelTDeltadoc) was constructed and purified from a recombinant Escherichia coli, and its enzyme properties were examined. CelTDeltadoc showed strong activity toward carboxymethylcellulose (CMC) and barley beta-glucan, and low activity toward xylan. The V(max) and K(m) values were 137 micro mol min(-1) mg(-1) and 16.7 mg/ml, respectively, for CMC. Immunological analysis indicated that CelT is a catalytic component of the C. thermocellum F1 cellulosome. This is the first report describing the characterization of a family 9 cellulase without an Ig-like domain or family 3c CBM.

Endothelial dysfunction is an independent factor responsible for vasospastic angina

In order to evaluate peripheral endothelial function in patients with vasospastic angina (VSA), we measured flow-mediated dilation (FMD) of the brachial artery in patients with VSA and compared it with FMD in patients without VSA. Endothelial dysfunction is considered one of the mechanisms underlying VSA. However, its exact role remains to be clarified. The study included 30 patients with positive spasm-provocational test results without evidence of significant coronary stenosis (VSA group) and 30 patients with negative spasm-provocational test results without evidence of significant coronary stenosis (control group). In each patient, brachial artery diameter responses to hyperemic flow and glyceryl trinitrate spray were measured using high-resolution ultrasound. The carotid intima-media thickness was also measured as a marker of systemic atherosclerosis. FMD was lower in the VSA group (4.8+/-0.5%) compared with the control group (9.4+/-0.7%, P<0.0001). In the VSA group, FMD was not affected by coronary risk factors or the presence of atherosclerotic changes on coronary angiography. Glyceryl trinitrate-induced dilation did not differ between the two groups. The intima-media thickness was comparable between the VSA (0.85+/-0.04 mm) and control groups (0.81+/-0.05 mm). These findings indicated that peripheral endothelial function is impaired only in the VSA group, whereas the atherosclerotic changes were similar in the two groups. We conclude that endothelial dysfunction may be an independent factor responsible for the development of VSA.

Usefulness of flow-mediated dilation of the brachial artery and/or the intima-media thickness of the carotid artery in predicting coronary narrowing in patients suspected of having coronary artery disease

It has been reported that flow-mediated dilation (FMD) of the brachial artery and the carotid intima-media thickness (IMT), markers of atherosclerosis, are altered in patients with coronary artery disease (CAD), but it is still not known if the presence of CAD can be detected using these markers. We examined whether the presence of CAD can be detected by FMD of the brachial artery and/or IMT. Eighty-one patients who underwent coronary angiography for the first time were enrolled. In each patient, brachial artery diameter responses to FMD and the administration of nitroglycerin spray, and carotid IMT were measured using high-resolution ultrasound (10 MHz) before coronary angiography. CAD was defined as >50% stenosis of a major coronary artery. Fifty-six patients had CAD. FMD was lower and IMT was greater in patients with CAD (FMD, 2.9 +/- 0.2% vs 9.4 +/- 0.5%; IMT, 1.09 +/- 0.05 vs 0.79 +/- 0.04 mm, both p <0.0001). Nitroglycerin-induced dilation did not differ in the 2 groups. Multivariate analysis showed that FMD was the only predictor of the presence of CAD (p = 0.0026). Receiver-operating characteristic analysis demonstrated that a cutoff value for FMD for detecting the presence of CAD was 6%, with a sensitivity of 0.93 (52 of 56) and a specificity of 0.88 (22 of 25). These findings suggest that FMD but not IMT may be used to detect the presence of CAD in patients with suspected CAD.

Molecular basis of the delayed rectifier current I(ks)in heart

J. Kurokawa, H. Abriel and R. S. Kass. Molecular Basis of the Delayed Rectifier Current I(Ks)in Heart. Journal of Molecular and Cellular Cardiology (2001) 33, 873-882. Electrical activity underlies the control of the frequency, strength, and duration of contraction of the heart. During the cardiac cycle, a regular rhythmic pattern must be established in time-dependent changes in ionic conductances in order to ensure events that underlie normal cardiac function. This pattern must be tightly regulated by sympathetic nervous activity to ensure a physiologically relevant relationship between diastolic filling and ejection times with variable heart rate. The duration of the ventricular action potential is controlled in part by a slowly activated potassium channel current, I(Ks). The molecular identity of the subunits that comprise the channels conducting this current is important, not only for understanding the fundamental mechanisms that control electrical activity in healthy individuals, but also for understanding the molecular basis of at least one inherited human disease, LQTS-1. This brief review summarizes key points of information regarding the molecular determinants of the activity of these channels, their relationship to human disease, and what is known, and yet to be discovered, about the molecular determinants of the regulation of this channel by sympathetic nervous activity.

Clinicopathological study of mucinous gastric carcinoma

BACKGROUND AND AIMS

Mucinous gastric carcinoma (MUC) is relatively a rare subtype of gastric carcinoma, and there has been considerable controversiy over the prognosis of this type of carcinoma. In this study we tried to analyze the clinicopathological differences between MUC and other types of gastric carcinoma (non-MUC) and determine whether MUC is associated with a worse prognosis than non-MUC.

MATERIAL AND METHODS

We reviewed 645 patients with pathologically confirmed gastric cancer who underwent gastrectomy in our facility during the period from 1975 through 1997. Among them, 20 patients (3.1%) had gastric carcinoma with (MUC), and 625 patients had it without extracellular mucin (non-MUC). In addition, we classified MUC into two groups (well-differentiated type; 7 cases and poorly differentiated type; 9 cases) and analyzed the differences between them.

RESULTS

The MUC tumors were more often located in the lower and the upper third of the stomach (MUC: 55% and 25%, non-mUC: 41% and 18%, respectively). The patients with MUC had more serosal invasion (t3 plus t4; MUC: 45%, non-MUC: 18%), more-invasive carcinoma (Type 3 plus 4; MUC: 60%, non-MUC: 36%) and more lymph-node involvement (MUC: 45%, non-MUC: 38%) than the patients with non-MUC. The patients with MUC were more advanced in stage at the time of diagnosis (Stage III plus IV; MUC: 50%, non-MUC: 26%) and had a higher peritoneal dissemination rate (MUC: 30%, non-MUC: 12%) and a lower curability rate (MUC: 60%, non-MUC: 78%) than the patients with non-MUC. The mean size of tumors in MUC (7.4 cm) was larger than that of non-MUC (5.5 cm). Therefore, the overall 5-year survival rate for MUC patients (33%) was lower than that for non-MUC patients (64%). There were no significant differences between well-differentiated and poorly differentiated subtypes of MUC except for the curability and peritoneal dissemination rates.

CONCLUSIONS

The overall survival rate for patients with MUC was worse than that for patients with non-MUC. The poor prognosis was correlated with more advanced stage at diagnosis and more frequent serosal invasion. These results suggest the need to diagnose patients with MUC in the early stage of cancer and that in the case of the advanced stage, wide excision of the surrounding tissues and aggressive lymph-node dissection will be needed.

Sequence of the Clostridium thermocellum mannanase gene man26B and characterization of the translated product

The man26B gene of Clostridium thermocellum strain F1 was found in pKS305, which had been selected as a recombinant plasmid conferring endoglucanase activity on Escherichia coli. The open reading frame of man26B consists of 1,773 nucleotides encoding a protein of 591 amino acids with a predicted molecular weight of 67,047. Man26B is a modular enzyme composed of an N-terminal signal peptide and three domains in the following order: a mannan-binding domain, a family 26 mannanase domain, and a dockerin domain responsible for cellulosome assembly. We found that this gene was a homologue of the man26A gene of C. thermocellum strain YS but that there were insertion or deletion mutations that caused a frame-shift mutation affecting a stretch of 26 amino acids in the catalytic domain. Man26B devoid of the dockerin domain was constructed and purified from a recombinant E. coli, and its enzyme properties were examined. Immunological analysis indicated that Man26B was a catalytic component of the C. thermocellum F1 cellulosome.

TEA(+)-sensitive KCNQ1 constructs reveal pore-independent access to KCNE1 in assembled I(Ks) channels

I(Ks), a slowly activating delayed rectifier K(+) current through channels formed by the assembly of two subunits KCNQ1 (KvLQT1) and KCNE1 (minK), contributes to the control of the cardiac action potential duration. Coassembly of the two subunits is essential in producing the characteristic and physiologically critical kinetics of assembled channels, but it is not yet clear where or how these subunits interact. Previous investigations of external access to the KCNE1 protein in assembled I(Ks) channels relied on occlusion of the pore by extracellular application of TEA(+), despite the very low TEA(+) sensitivity (estimated EC(50) > 100 mM) of channels encoded by coassembly of wild-type KCNQ1 with the wild type (WT) or a series of cysteine-mutated KCNE1 constructs. We have engineered a high affinity TEA(+) binding site into the h-KCNQ1 channel by either a single (V319Y) or double (K318I, V319Y) mutation, and retested it for pore-delimited access to specific sites on coassembled KCNE1 subunits. Coexpression of either KCNQ1 construct with WT KCNE1 in Chinese hamster ovary cells does not alter the TEA(+) sensitivity of the homomeric channels (IC(50) approximately 0.4 mM [TEA(+)](out)), providing evidence that KCNE1 coassembly does not markedly alter the structure of the outer pore of the KCNQ1 channel. Coexpression of a cysteine-substituted KCNE1 (F54C) with V319Y significantly increases the sensitivity of channels to external Cd(2+), but neither the extent of nor the kinetics of the onset of (or the recovery from) Cd(2+) block was affected by [TEA(+)](o) at 10x the IC(50) for channel block. These data strongly suggest that access of Cd(2+) to the cysteine-mutated site on KCNE1 is independent of pore occlusion caused by TEA(+) binding to the outer region of the KCNE1/V319Y pore, and that KCNE1 does not reside within the pore region of the assembled channels.

[A case of left renal cell carcinoma in a young male adult with left varicocele]

A 25-year-old man presented to our hospital with the chief complaint of left-sided painless scrotal swelling. Varicocele was diagnosed and high ligation was performed. Two months later, he noticed asymptomatic gross hematuria. Transabdominal ultrasonography and abdominal computed tomographic scanning showed a left renal tumor measuring more than 10 cm in diameter. Radical nephrectomy (thoraco-abdominal approach) was performed and pathological diagnosis was granular cell carcinoma (G2, pT2, INF alpha, pNX, pMX). He then received intramuscular injections of interferon-alpha 3 million units on three days per week. The frequency of renal cell carcinoma was reported to be about 1-3% for individuals in the 20s in the recent Japanese literature, and renal cell carcinoma in a young man with left varicocele is very rare.

[Psychogenic lower urinary tract dysfunction in women: patho-physiological investigation for psychogenic frequency-urgency syndrome and psychogenic urinary retention]

PURPOSE

Psychogenic lower urinary tract dysfunction (PLUTD) is composed of two syndromes; psychogenic frequency-urgency syndrome (PFUS) and psychogenic urinary retention (PUR). We evaluated the patho-physiology of PFUS and PUR, and explored the different pathogenesis in these syndromes.

MATERIAL AND METHODS

Forty five patients with PLUTD, consisting of 23 patients with PFUS and 22 patients with PUR were investigated by using the psychological tests: CMI (Cornell Medical Index) and TEG (Todai's Egogram), a quantitative perspiration test in 45 females (23 patients with PFUS and 22 patients with PUR), and simultaneous measurements of voiding cysto-urethrography and urodynamic studies using the Life-Tech 6 channel polygraph in 35 patients (17 patients with PFUS and 18 patients with PUR).

RESULTS

The prevalence in ages revealed two peaks, 20 years and 50 to 60 years. Over 25% of them had pyuria more than 10/hpf of WBC. Peak flow rate measured by uroflowmetry showed normal range in PFUS group and decreased in PUR group. The functional vesical volume was less than 100 ml in most patients with PFUS. Residual urine in PUR group was significantly greater. Capacity of the PFUS group were able to hold over 400 ml of contrast instilled through the urethral catheter, despite increased desire to void. Over 15% of the study group with PFUS showed uninhibited systolic contraction of detrusor (> 15 cm H2O) during filling phase. The measurement value of urodynamic parameters demonstrated that a periodic follow-up survey of the upper urinary tract should be performed because of the low compliance bladder in the patients with PLUTD. During voiding phase, the women with PFUS had a tendency to be divided into two groups, hypercontractile or acontractile detrusor. The voiding cysto-urethrography (VCUG) showed a tendency of bladder neck opening on patients with PFUS during filling phase. Most of PLUTD cases demonstrated a round to triangle shape on vesical configuration, which led to a spastic condition of detrusor muscle. We attempted to measure the quantitative perspiration using 3 kinds of loading tests; respiratory, arithmetic and psychological load. In the psychological loading test, we asked 98 questions about their daily lives including occupation, living condition, family relationship and sexual activities. Arithmetic loading test consisted of counting in reverse, subtraction and multiplication. The quantitative perspiration rate resulted in a "positive" in many patients with PFUS. Respiration loading test was performed to measure the respiration volume during 3 large inhales. Most patients with PUR tested within the normal range for respiration except for those patients with decreased or no perspiration during the psychiatric loading test. These results may reflect the psychological elements including suppression and subconscious defense mechanism. Neurosis which was diagnosed as having type III to type IV of the Cornell Medical Index was demonstrated in less than under 40% of patients with PFUS and more than 55% patients with PUR. There was no significant trend or difference between PFUS and PUR detected from Todai's Egogram.

CONCLUSIONS

Due to the reflection of many psychological responses, it is necessary to investigate from various examinations including psychological, autonomical and classical urological studies for accurate diagnosis of PLUTD.

Effect of adenosine triphosphate on human coronary circulation

We investigated in humans the effects of adenosine triphosphate (ATP), administered by intracoronary bolus (4-16 microg) or intravenous infusion (25-200 microg/kg/min), on coronary and systemic hemodynamics and electrocardiogram (ECG) variables. All patients had normal epicardial coronary arteries. The maximal coronary blood flow velocity (CBFV) was determined with intracoronary bolus of papaverine. A 12 microg bolus of ATP (n=12) caused maximal coronary hyperemia similar to that caused by papaverine. Intracoronary boluses caused a small brief decrease in arterial pressure but no significant changes in HR or ECG variables. Intravenous infusion of ATP at 150 microg/kg/min (n=15) caused a decrease in the coronary resistance index similar to that caused by papaverine, but the rate of increase in CBFV by ATP was smaller than that caused by papaverine. No patients had a significant change in ECG variables, but some patients (40%) had a serious decrease in arterial pressure. These studies suggest that maximal coronary vasodilation can be achieved safely with intracoronary ATP administration and that intravenous infusions at 150 microg/kg/min cause near-maximal coronary hyperemia in most patients.

[A case of renal oncocytoma associated with acquired cystic disease of the kidney]

We report a case of renal oncocytoma associated with acquired cystic disease of kidney (ACDK). A right renal mass was incidentally found on an annual ultrasonography of the kidneys in a 56-year-old female patient who had been on maintenance hemodialysis for 6 years. Computerized tomography (CT) showed a right hypervascular renal mass, suggesting a renal cell carcinoma associated with ACDK. Right radical nephrectomy was performed. The post-operative pathological diagnosis was renal oncocytoma. Renal oncocytoma in ACDK is very rare, and the pathological characteristics of oncocytoma are discussed.

[A case of spontaneous repair of the ureteral rupture caused by ureteral carcinoma]

We report a 47-year-old male patient with a spontaneous ureteral rupture caused by ureteral carcinoma. Drip infusion pyelography (DIP) and computerized tomography (CT) demonstrated the extravasation of contrast medium around the dilated upper ureter. Nephrostography showed the extinction of extravasation 4 days after the DIP. A total nephroureterectomy with the excision of a cuff of bladder was performed for the transitional cell carcinoma of the right lower ureter. Meticulous pathological examination of the specimen revealed discontinuity of the muscle layer, edema and fibrin deposition in the submucosal layers in the upper ureter indicating the site of the rupture. These findings suggest that the spontaneous rupture of the ureter caused by the ureteral carcinoma could be spontaneously repaired in a short period.

Effects of a novel, potent benzothiazepine Ca2+ channel antagonist, DTZ323, on guinea-pig ventricular myocytes

The effects of a 1,5-benzothiazepine derivative, (+)-cis-3-(acetyloxy)-5-[2-[[2-(3,4-dimethoxyphenyl)ethyl]-methyla mino]ethyl]-2,3-dihydro-2-(4-methyoxyphenyl)-1,5-benzothiazepine-4 (5H)-one (DTZ323), on membrane currents were investigated in guinea-pig ventricular myocytes using the whole-cell patch-clamp technique. DTZ323 suppressed the L-type Ca2+ channel currents (I[Ca(L)]) more selectively than the T-type Ca2+ channel and the Na+ channel currents. DTZ323 inhibited I[Ca(L)] in a use- and a voltage-dependent manner with 24 times higher potency than that of diltiazem. Rate of recovery of I[Ca(L)] from the conditioned block by DTZ323 was faster compared with diltiazem and verapamil, and was steeply dependent on the holding potential at resting membrane potential range in ventricular myocytes (-90 to -60 mV). Our results suggest that DTZ323 is a selective Ca2+ channel antagonist, the most potent among the 1,5-benzothiazepine Ca2+ channel antagonists, and that the voltage- and use-dependent effect of DTZ323 on I[Ca(L)] is due to the steep voltage dependence of the rate of dissociation from the cardiac L-type Ca2+ channels.

1,5-benzothiazepine binding domain is located on the extracellular side of the cardiac L-type Ca2+ channel

To determine whether 1,5-benzothiazepine Ca2+ channel blocker approaches its binding domain within the cardiac L-type Ca2+ channel from inside or outside of the membrane, we tested the effects of a novel potent 1,5-benzothiazepine derivative (DTZ323) and its quaternary ammonium derivative (DTZ417) on guinea pig ventricular myocytes by using the whole-cell patch-clamp technique. The extracellular application of DTZ417 suppressed the L-type Ca2+ channel currents (I[Ca(L)]) with an IC50 value of 1.2 +/- 0.02 microM, which was close to the IC50 value of diltiazem (0.63 +/- 0.01 microM). The suppression of I[Ca(L)] by DTZ417 was voltage and use dependent but lacked tonic block, which allowed us to investigate the onset of the effect on I[Ca(L)] by changing the holding potential (HP) from -90 to -50 mV in the presence of DTZ417. DTZ417 did not have significant effects on I[Ca(L)] at an HP of -90 mV. At -50 mV, DTZ417 (50 microM) applied from the extracellular side completely suppressed I[Ca(L)], whereas it had no effect from the intracellular side. DTZ323 (1 microM) also inhibited I[Ca(L)] only from the extracellular side, without any effects by the intracellular application of < or = 10 microM. However, a quaternary phenylalkylamine derivative, D890 (0.1 mM), acted only from the intracellular side. These results suggest that in contrast to the phenylalkylamine binding site, in cardiac myocytes the 1,5-benzothiazepine binding site is accessible from the extracellular side of the L-type Ca2+ channel.

Diltiazem derivatives modulate the dihydropyridine-binding to intact rat ventricular myocytes

To examine whether the modulation of the 1,4-dihydropyridine-binding by diltiazem derivatives, which has been shown in cardiac and skeletal muscle membranes, takes place in intact cardiac myocytes, effects of diltiazem on the specific binding of [3H](+)-PN200-110 to freshly isolated adult rat ventricular myocytes were investigated in normal Tyrode solution at 37 degrees C. Diltiazem consistently potentiated the [3H](+)-PN200-110-binding in a concentration-dependent manner, while DTZ323 (3-(acetyloxy)-5-[2-[[2- (3,4-dimethoxyphenyl)ethyl]-methylamino]ethyl]-2,3-dihydro-2(-4 methoxyphenyl)-1,5-benzothiazepin-4-(5H)-one), a potent diltiazem derivative, inhibited it in a non-competitive manner. In saturation studies, 100 microM decreased the Kd value of the 3[H](+)-PN200-110-binding (control, 0.102 +/- 0.008 vs. diltiazem, 0.074 +/- 0.004 (nM, n = 6), P < 0.05) without significant effect on Bmax (control, 65.7 +/- 6.4 vs. diltiazem, 76.7 +/- 4.4 (fmol/mg protein, n = 6). Moreover, membrane-impermeant quaternary diltiazem also potentiated the [3H](+)-PN200-110-binding in intact myocytes. These results suggest that diltiazem modulates the 1,4-dihydro-pyridine-binding even in intact cardiac myocytes, and the binding site of diltiazem is accessible from the extracellular side of the L-type Ca2+ channels.

Complications and reimplantation of penile implants

BACKGROUND

Complications of penile prosthesis implants can be divided into surgical and mechanical failure. We investigated penile prosthesis implants to clarify the surgical and mechanical complications that have arisen in our clinical experience.

METHODS

In the 11 years between 1984 and 1995, 83 penile prostheses were implanted in 74 patients ranging from 37 to 82 years of age.

RESULTS

Of the 64 malleable and mechanical prostheses, 11 were extracted, including 4 removed because of surgical complications and 2 due to mechanical failure. Of the 19 inflatable prostheses, 6 were removed, including 1 extracted due to surgical complication and 5 extracted due to mechanical failure. Nine reimplantations for 8 patients were performed and all these cases had good results. As a result, 66 out of 74 patients could have coitus after prosthetic surgery.

CONCLUSIONS

Penile prosthetic surgery is an established method of treating organic impotence, however, it should only be considered for selected and well-informed patients to avoid complications and revision surgery.

[Endothelin levels after extracorporeal shock waves, effects of renal function and blood pressure in rats]

BACKGROUND

Endothelin is a recently discovered peptide with strong vasoconstrictive effects which is of potential relevance in the development of renal hypertension and renal failure. It is secreted by endothelial cells in response to ischemia, endothelial lesions and inflammatory or traumatic processes. Endothelin level after extracorporeal shock waves, effects of renal function and blood pressure were examined in rats.

METHODS

Changes of plasma endothelin-1 (ET-1) levels after extracorporal shock waves were studied by applying 500 shock waves to both kidneys in Wistar Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Plasma ET-1 was measured before shock wave exposure and every thirty minutes up until 2 hours, then at 12 hours and 24 hours after shock wave exposure by specific sandwich enzyme immunoassay (EIA). Findings were then compared with those from the control group. Mean arterial pressure (MAP), glomerular filtration rate (GFR) and renal plasma flow (RPF) in rats were measured before shock wave exposure and every thirty minutes up until 2 hours after shock wave exposure, moreover made evaluation when ET-1 specific antibodies were administered intravenously into WKY and SHR.

RESULTS

Plasma ET-1 was significantly increased in WKY (n = 6) and SHR (n = 7) after shock wave exposure as compared with that in the control group (p < 0.05). In SHR (n = 6), GFR temporarily decreased at 60 min but RPF remarkably decreased and renal vascular resistance (RVR) increased at 30 approximately 120 min after shock wave exposure (p < 0.05). However, infusion of ET-1 specific antibodies into SHR curbed change in those parameters, increased GFR and RPF at 60 approximately 120 min after shock wave exposure (p < 0.05). In WKY (n = 5), RPF temporarily decreased and RVR slightly increased, infusion of ET-1 specific antibodies curbed change in those parameters. MAP in SHR slightly increased at 30 min after shock wave exposure, but there was no significant change in WKY.

CONCLUSION

These results suggest that plasma ET-1 levels elevated in both strains and ET-1 influenced renal function after extracorporeal shock waves, and that SHR is more sensitive to ET-1 in comparison with WKY.

[Clinical experience with the artificial urinary sphincter AMS 800 for male incontinence]

BACKGROUND

The aim of this study is to evaluate the therapeutic efficacy of artificial urinary sphincter AMS 800 implants for male patients with urinary incontinence.

METHODS

Eleven male patients with urinary incontinence were treated by implantation of the artificial urinary sphincter AMS 800 between 1988 and 1992. Patient age at the surgery ranged from 14 to 79 years, with a mean age of 58 years. At presentation, 9 patients (82%) had true incontinence and 2 had overflow incontinence, and medical treatments and/or surgical procedures (Teflon injections in 2 and Sling procedure in 1) had been attempted previously elsewhere in all patients. The etiologies of incontinence were post-prostatectomy (transurethral resection in 4 and radical retropubic prostatectomy in 4) in 8 patients (73%) and myelomeningocele, spinal cord injury, pelvic trauma in one each. There were 5 patients with abnormal cystometrogram, and 2 of them were performing intermittent self catheterization. Vesicoureteral reflux was determined in 2 patients preoperatively, which were surgically corrected one year before AMS800 implant in a patient and simultaneously in another patient. The cuff was placed around the bulbous urethra (9), pendulous urethra (1) or bladder neck (1). The device was activated 6 weeks post implantation, and the assessment of therapeutic effects was started 2 weeks after activation.

RESULTS

Follow up ranged from 3 weeks to 75 months, with a mean of 56 months, if 3 cases done explantation due to periprosthetic infections were excluded. After AMS 800 implantation 5 patients (45%) were completely continent, 4(36%) required the use of not more than 1 pad per day, while a patient was not satisfied with the results and another patient was not definitive because of early explantation before device activation. Hence complete or near complete continence was achieved in 9 patients (81%). A patient is performing intermittent self catheterization in conjunction with the AMS 800 without any complications up until now. There were 3 periprosthetic infections (27%) associated with 2 cuff erosions, that consequently required explantation. Besides periprosthetic infection, neither complications nor mechanical device failures was experienced.

CONCLUSION

In conclusion, the AMS 800 artificial urinary sphincter was safe with reasonable mechanical reliability and offered acceptable and satisfactory urinary control to the selected patients with incontinence.

High dose of fluvastatin sodium (XU62-320), a new inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, lowers plasma cholesterol levels in homozygous Watanabe-heritable hyperlipidemic rabbits

The effects of fluvastatin sodium (XU62-320), a new type of inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, on plasma cholesterol and triacylglycerol levels were investigated using homozygous Watanabe-heritable hyperlipidemic (WHHL) rabbit, an LDL-receptor-deficient animal which expresses a hepatic LDL receptor activity less than 5% that of control rabbits. Plasma levels of total, VLDL- and LDL-cholesterol were decreased profoundly after oral administration of fluvastatin at a dose of 50 mg/kg per day for 4 weeks. Plasma triacylglycerol levels were not affected by fluvastatin. Hepatic HMG-CoA reductase activity increased by 3-fold and hepatic LDL receptor activity increased by only 3.7-fold, as calculated by Scatchard plot analysis, with fluvastatin administration for 4 weeks, and the hepatic mRNA level for the rabbit LDL receptor was increased by 3-fold. Combined administration of fluvastatin (50 mg/kg per day) and cholestyramine, a bile acid sequestrant resin, at a level of 2% of the diet for 4 weeks more profoundly decreased plasma total, VLDL- and LDL-cholesterol levels with induction of hepatic cholesterol 7 alpha-hydroxylase and no further induction of the hepatic LDL receptor. Plasma triacylglycerol levels were increased by the combination treatment. These results suggest that high dose of fluvastatin sodium is effective in lowering plasma cholesterol levels in homozygous WHHL rabbits through the shared mechanisms involving decrease in production and secretion of cholesterol from the liver and the induction of hepatic LDL receptor. Additional effect of cholestyramine on decrease in plasma cholesterol levels seems to be due to the further decrease in hepatic cholesterol secretion by up-regulation of hepatic cholesterol 7 alpha-hydroxylase.

Effect of pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, on hepatic cholesterol 7 alpha-hydroxylase, acyl-coenzyme A: cholesterol acyltransferase, and bile lipid secretion in the hamster with intact enterohepatic circulation

The effects of administration of pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, on hepatic cholesterol 7 alpha-hydroxylase and acyl-coenzyme A: cholesterol acyltransferase (ACAT) activities and bile lipid secretion were investigated in Syrian golden hamsters. Continuous administration of pravastatin induced no significant changes in hepatic cholesterol content, ACAT and cholesterol 7 alpha-hydroxylase activities, or bile lipid and acid composition. Abrupt withdrawal of pravastatin induced increases in hepatic cholesterol content and ACAT activity and no change in hepatic cholesterol 7 alpha-hydroxylase activity, and increased cholesterol saturation in bile. Hepatic cholesterol 7 alpha-hydroxylase activity paralleled hepatic mRNA levels of this enzyme. These results suggest that a change in hepatic cholesterol metabolism induced by continuous administration of pravastatin maintains a constant net balance of hepatic cholesterol content. In addition, the drug has no deleterious influence on metabolism of bile lipids and acids and related enzymes, except for a transient increase in cholesterol saturation in bile induced by an inappropriate increase in hepatic cholesterol content and a lack of response of cholesterol 7 alpha-hydroxylase activity to changes in hepatic cholesterol content upon abrupt withdrawal of pravastatin.

Identification of a functional receptor differing from the LDL receptor that catabolizes chylomicron remnant in Hep G2 cells

We investigated types of lipoprotein receptors on Hep G2 cells using a monoclonal antibody against the LDL receptor. IgG-C7 inhibited the binding and internalization of 125I-labeled low density lipoprotein (LDL) in Hep G2 cells with upregulated and downregulated LDL receptors by 90% of control values. Binding and internalization of 125I-labeled chylomicron remnant in Hep G2 cells with upregulated and downregulated LDL receptors was 50% and 85%, respectively, of control values after exposure to IgG-C7. Excess unlabeled chylomicron remnant inhibited binding and internalization of 125I-labeled chylomicron remnant in Hep G2 cells with downregulated LDL receptors completely. Pronase treatment abolished binding and internalization of 125I-labeled LDL and 125I-labeled chylomicron remnant in Hep G2 cells. When solubilized fractions of Hep G2 cells were immunoprecipitated with IgG-C7, the binding activity of 125I-labeled chylomicron remnant to reconstituted vesicles was unchanged. 45Ca blotting analysis showed the presence of 45Ca binding protein (approximately 600 kDa) in Hep G2 cells. The amount of 45Ca binding protein was not affected by cholesterol and was abolished by pronase treatment. These results suggest the existence of a functional receptor other than the LDL receptor that catabolizes chylomicron remnant in Hep G2 cells and that this receptor may correspond to LDL receptor-related protein.

[Clinical analysis in 2266 cases of transurethral resection of the prostate]

During the past 20 years from August 1971 to July 1991, 3215 cases of transurethral resection were performed at Kitasato University Hospital, and consisted of 2008 benign prostatic hyperplasias, 692 bladder tumors, 258 prostate cancers, 167 bladder neck contractures, 38 urethral strictures, 20 chronic prostatities and 32 various urologic diseases. On 2266 transurethral resections of the prostate including 2008 benign prostatic hyperplasias, and 258 prostate cancers analysis was conducted. Patient age ranged from 44 to 97 (mean, 70.1). Resected tissue varied from 1 to 177 (mean, 26.9) grams. The time required for resection was from 9 to 245 (mean, 73.0) minutes. The volume of irrigation fluid was from 4 to 92 (mean, 25.0) liters. The duration of catheter placement after operation was 3 to 44 (mean, 4.1) days and hospitalization, 10 to 81 (mean, 12.1) days. The number of complications and blood transfusions were 308 (13.6%) and 381 (16.8%) respectively. Resected amount of tissue, volume of irrigation fluid, duration of catheter placement and frequency of complication in the benign prostatic hyperplasia group exceeded those in prostate cancer group. The length of hospitalization and blood transfusion rates were higher in the prostate cancer group. The rate or frequency of each item increased with the operating time and amount of resected tissue. Today, 60 minutes of operating time as a limiting factor of transurethral resection is not considered a important factor. Based on the results of the 2266 TURP cases, an attempt will be made to establish safer methods of treatment.

[Pre-operative, operative and postoperative complications in 2266 cases of transurethral resection of the prostate]

Pre-operative and operative complications in 2266 patients having undergone transurethral resection of prostate (TURP) for the past 20 years at Kitasato University Hospital were analyzed. They consisted of 2008 benign prostatic hyperplasia and 258 prostate cancer patients. Seven hundred and fifty four patients showed some of physical disorders prior to TUR:hypertension in 147 cases, diabetes mallitus in 87, ischemic heart disease in 46, chronic obstructive lung disease in 41 and others. Operative and postoperative complications of TURP were seen in 308 cases (13.6%). Perforation of the prostatic capsule was seen in 100 cases (4.4%) and bladder perforation into intraperitoneal cavity in 6 cases (0.3%). Transurethral fulgulation for postoperative hemorrhage was conducted on 79 cases (3.5%). Hyponatremia lower than 130 mEq/L was noted in 14 cases (0.6%). Severe urinary tract infection leading to bacteremia was observed in 9 cases (0.4%). Postoperative epididymitis was evident in 20 cases (0.8%). There was postoperative urinary incontinence in 19 cases, 3 of which was treated with Teflon-paste injection successfully. One patient had to undergo AMS-800 artificial sphincter implantation. The number of postoperative urethral stricture patients requiring urethral dilatation or internal urethrotomy was 12 (0.5%) and postoperative bladder neck contracture was seen in 20 cases (0.9%). One patient (0.04%) who developed DIC after profuse postoperative hemorrhage died on the 37th postoperative day. The efficiency of TURP depends not so much on the skill of cutting as on the speed and accuracy of orientation and haemostasis. The quick recognition of anatomical landmarks will assure effective and safe resection.

Effect of fluvastatin sodium (XU62-320), a new inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, on the induction of low-density lipoprotein receptor in HepG2 cells

The effect of fluvastatin sodium (XU62-320), a new type of inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A, on the induction of LDL receptor in the human liver-derived cell line HepG2 was investigated. Fluvastatin sodium produced marked inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and induction of LDL receptor on HepG2 cells at a concentration of 0.1-1.0 microM. These results suggest that fluvastatin sodium has potential for use as a strong plasma cholesterol-lowering drug.

Partial cloning of cDNA for hamster liver cholesterol 7 alpha-hydroxylase

A partial cDNA clone encoding cholesterol 7 alpha-hydroxylase (pHA 7 alpha-3) was isolated from a hamster liver cDNA library using rat P-450 ch7 cDNA (p 7 alpha-11) as a probe. In comparison with the complete base sequence of p 7 alpha-11, pHA 7 alpha-3 lacked about 500 base pairs at the 5' end. Circadian rhythms of mRNA for hamster liver 3-hydroxy-3-methylglutaryl coenzyme A reductase and cholesterol 7 alpha-hydroxylase were investigated with cDNA clones encoding 3-hydroxy-3-methylglutaryl coenzyme A reductase (pRed-227) and pHA 7 alpha-3. Typical circadian rhythms of mRNA for both enzymes and a time lag between the two circadian rhythms were observed. The circadian rhythm of activity for each enzyme corresponded to that of each mRNA.

Role of cholesterol-accumulating macrophages on vascular smooth muscle cell proliferation

The proliferation of vascular smooth muscle cells (VSMC) was stimulated by co-incubation with macrophages. Further stimulation was observed when co-incubated macrophages were supplied with LDL or cholesterol. However, the stimulation of VSMC proliferation did not result from co-incubation with macrophages supplemented with acetylated LDL or delipidated LDL. The addition of anti-PDGF antibody partially abolished the stimulation of VSMC proliferation induced by co-incubation with macrophages supplemented with LDL or cholesterol. A high concentration of prostaglandin E2 inhibited the proliferation of VSMC stimulated by PDGF and plasma-derived serum when they were at the G0/G1 stage. However, the inhibitory effect of prostaglandin E2 on proliferation was not observed when cells were incubated with macrophages supplemented with LDL or cholesterol in spite of the promotion under these conditions of prostaglandin E2 production. These results suggest that cholesterol-accumulating macrophages may exert a regulatory effect on the proliferation of VSMC through the synthesis and secretion of platelet-derived growth factor (PDGF) and prostaglandin E2, besides foam-cell formation.

[Pure yolk sac tumor of the testis with brain metastasis: report of an adult case]

Herein we report an adult case of pure yolk sac tumor with brain metastasis. The patient was a 37-year-old male who presented with indulation of his left scrotum for 10 months. The plain computerized tomographic (CT) scan on entry demonstrated tumor metastasis to his lung and liver and serum alpha-fetoprotein (AFP) level was 786 ng/ml. Five days after admission, he developed hemiplegia secondary to the cerebral metastasis and hemorrhage. After chemotherapy and operation of right-posterior lobectomy, PVB (cisplatinum, vinblastine, bleomycin) chemotherapy produced a complete remission and the elevated serum AFP was normalized. However, the second course of chemotherapy had to be discontinued because of drug-induced hepatitis. He died of massive tumor metastasis to his brain 6 months after craniotomy.

[Evaluation of renal function with dynamic Gd-DTPA-enhanced magnetic resonance imaging after shock wave lithotripsy]

It has already been reported that MR imaging is a superior imaging technique to detect minute anatomical changes in the kidney after ESWL. However, the morphological abnormalities found by MR imaging do not necessarily mean deterioration of the renal function. The purpose of this study is to assess the morphological changes in the kidney and changes in renal function after the ESWL treatment by dynamic MR imaging. A total of 16 patients underwent axial MR imaging before and after ESWL. Dynamic MR was also performed on 11 patients of them within 24 hours after ESWL, and both before and after ESWL in the remaining 5 patients. Eight kidneys showed morphological abnormalities on T1-weight images, and 4 of them showed loss of corticomedullary demarcation. Furthermore, the first MR imaging after injection of GdDTPA revealed focal areas of decreased signal intensity in only 2 of these 4 patients who showed loss of corticomedullary demarcation on previous MR images. However, the second MR imaging 6 months after ESWL showed no abnormality in either of them. The percent contrast of signal intensity increase to fat signal intensity was one minute after GdDTPA injection compared before and after ESWL in 5 of the 16 patients. The values before and after ESWL revealed no statistically significant difference, and no patient showed any remarkable decrease of signal intensity after ESWL. These results suggest that loss of corticomedullary demarcation after ESWL does not necessarily reflect damage to the renal function and that the shock-wave exposure causes no permanent damage to the renal function but only temporary impairment.

[A study on local administration of thrombin following transurethral resection of the prostate--clinical investigation with four-way balloon catheter]

The effect of local administration of thrombin via a newly devised four-way balloon indwelling catheter was investigated on 89 patients who underwent transurethral resection of the prostate (TURP). The catheter was introduced into the bladder immediately after TURP, the balloon was inflated with sterile water and mild moist sponge traction was applied to seal the bladder neck for 15 minutes. At the same time, the thrombin solution, 5,000 U in 5 ml of saline, was then injected into the prostatic fossa via the newly added infusion channel to promote early hemostasis. The results were compared with those of 36 randomized control patients, who were treated with the conventional three-way balloon catheter of the same size. The results obtained with this new device were favorable, showing significantly less postoperative hemorrhage in the thrombin infusion group than in the control group. In 7 of 89 thrombin infused patients, serum FDP revealed mild elevation for 2 hours after TURP. In 2 of these 7 patients FDP was closely correlated with thrombin infusion. However, no adverse reactions were observed in any patient in the thrombin infusion group. In conclusion, our new device to administer locally the thrombin solution is effective and safe for management of bleeding after TURP.

[A case of polycystic kidney with bilateral nephrectomy]

A 56-year-old woman in chronic hemodialysis had been suffering from uncontrollable fever for the past 7 months. Her original disease was diagnosed as familial polycystic kidney and three of her five brothers were found to have the same disease. Her chromosome was 46,XX,21P+ and laboratory examination revealed severe anemia, malnutrition, liver dysfunction, pyuria and candidiasis of urine. Abdominal echogram and CT scan revealed polycystic kidneys and multiple liver cysts. She was admitted to our hospital and was diagnosed as having pyelonephritis of the right kidney. As her condition was not improved by conservative therapy right nephrectomy was performed. One month later, spiking fever and left tenderness reappeared. Those symptoms could not be controlled by conservative therapy and left nephrectomy was performed again. Pathological examination on nephrectomized kidneys showed interstitial nephritis, hyaline degeneration and proliferative change of glomeruli, microabscess, colloid of tubules and calcification of parts of Henle's loops. Nephrectomy has been performed in 1.6 to 10.0% of polycystic kidneys due to references since 1952. Eight of the 22 polycystic kidneys (36.3%) seen at our hospital during the past 10 years have been removed.

[Neurogenic bladder with pituitary adenoma: report of two cases]

Two cases of neurogenic bladder with pituitary adenoma are reported. The pituitary adenomas produced excessive GH (growth hormone). The etiology of the neurogenic bladder was not identified by X-ray examination or any other tests. Urodynamic study, however, indicated a functional cause of neurogenic bladder. Case 1 was a 55-year-old male, who had a relatively small pituitary adenoma with mild symptoms. Urologically, there was complete urinary retention. Cystometrogram showed a flaccid pattern, detrusor-sphincter dyssynergia in sphincter-EMG and ice water test was negative. Case 2 was a 67-year-old female, who had a large pituitary adenoma and severe symptoms. Cystometrogram showed an almost normal pattern, however, there was detrusor-sphincter dyssynergia and ice water test was negative. We suggested that the neuropeptide takes some part in the pathophysiologic cause of neurogenic bladder.