New enzymatic method with tryptophanase for determining potassium in serum

We established a simple and rapid enzymatic method for measuring potassium ion in serum by using tryptophanase (EC 4.1.99.1) purified from Escherichia coli K12 strain (E. coli K12 IFO 3301). The presence of pyridoxal 5-phosphate promotes this enzymatic reaction, and potassium and (or) ammonium ions further accelerate it, with ammonium and potassium ions providing equivalent acceleration. We eliminated endogenous ammonium ion by using glutamate dehydrogenase (GLDH; EC 1.4.1.4), then produced ammonium ion in the presence of tryptophanase, tryptophan, and pyridoxal 5-phosphate. The concentration of formed ammonium ion, which was proportional to that of potassium ion in sample, was determined by adding GLDH to produce NADP+ in the presence of 2-oxoglutarate and NADPH; we then read the change of absorbance at 340 nm. The standard curve was linear for potassium ion concentrations up to 7.00 mmol/L. The within-assay variation (CV) was 0.89% at 5.51 mmol/L and 1.32% at 3.37 mmol/L. The day-to-day CVs were 0.99% at 6.85 mmol/L and 1.71% at 3.52 mmol/L. Analytical recoveries ranged from 98.7% to 108.9%. The correlation coefficient between values obtained with this enzymatic assay (y) and by flame photometry (x) was 0.995: y = 0.984x + 0.091 mmol/L (Sy.x = 0.105, n = 100). The presence of hemoglobin, bilirubin, or other cations little affects this system.

How does RNase H recognize a DNA.RNA hybrid?

The mechanism of RNase H substrate recognition is proposed from a model of a chemically modified DNA.RNA hybrid Escherichia coli RNase H complex. Site-directed mutagenesis of the enzyme and substrate titration observed by heteronuclear two-dimensional NMR spectra have been carried out. A model complex has been built, based on free structures of the enzyme and the substrate independently determined by x-ray crystallography and NMR distance geometry, respectively. In addition to steric and electrostatic complementarities between the molecular surfaces of the enzyme and the minor groove of the hybrid in the model, putative hydrogen bonds between the polar groups in the enzyme and 2'-oxygens of the RNA strand of the hybrid fix the hybrid close to the active site of the enzyme. The enzymatic activities of the mutant proteins and the changes in NMR spectra during the course of substrate titration are consistent with the present model. Moreover, the specific cleavage of the RNA strand in DNA.RNA hybrids can be explained as well as cleavage modes in modified heteroduplexes. A mechanism of enzymatic action is proposed.

Shift in the megakaryocyte ploidy in MDS patients: microcytofluorometry with DAPI staining after destaining of Wright-Giemsa stain

We applied DAPI (4',6-diamidino-2-phenylindole) staining to the determination of nuclear DNA content in single megakaryocytes in 12 normal subjects and 12 patients with myelodysplastic syndrome (MDS). After the megakaryocytes had been identified on Wright-Giemsa stained smear and classified according to modified Feinendegen's classification, they were photographed. Then Wright-Giemsa stain was removed by immersion in 50% ethanol at 37 degrees C for 1 h and 100% methanol at 37 degrees C for 1 h. The specimens were then stained with DAPI solution (DAPI 0.01 mg/ml, pH 7.4 Tris-EDTA-2Na buffer solution and 0.01 M 2-mercaptoethylamine hydrochloride mixed at the ratio of 0.5:98.5:1.0) for more than 30 min. The amount of nuclear DNA in the previously identified megakaryocytes was measured by microcytofluorometry. The maximum population of megakaryocytes ploidy was in 16N in normal subjects, 8N in 10/12 MDS patients, and 4N in the remaining two patients. These findings suggest impairment of the development of the megakaryocytes nucleus in the MDS patients.

Effect of dietary safflower phospholipid on plasma and liver lipids in rats fed a hypercholesterolemic diet

The effect of safflower phospholipid (SP) on plasma and liver lipids in rats fed a hypercholesterolemic diet was examined. Triglyceride mixture (SPO) of safflower oil and palm oil (8:2) containing almost comparable amounts of linoleic acid to safflower phospholipid was used as a control diet. Similarly, the effect of paste safflower phospholipid (PSP) which contains approximately 45% of neutral lipid was also compared to safflower oil (SO). Concentrations of total cholesterol in plasma and liver of rats fed the SP diet were markedly decreased in comparison with those of the other diets, but a slight reduction of total cholesterol in plasma and liver was observed in rats fed PSP diet. SP and PSP induced a reduction in the plasma level of low density lipoprotein (LDL) cholesterol as well as an increase in the level of high density lipoprotein (HDL) cholesterol. The activity of plasma lecithin-cholesterol acyltransferase (LCAT) was greatly increased in rats fed SP diet. These results suggest that the safflower phospholipids suppress the elevation of plasma and liver cholesterol and that this effect may depend on the phospholipid content in dietary lipid.

Impaired autologous mixed-lymphocyte reaction of peripheral blood lymphocytes in adult periodontitis

The autologous mixed-lymphocyte reactions (AMLR) of peripheral blood lymphocytes from 80 patients with adult periodontitis were examined. Some but not all patients showed clearly low AMLR responses; 31 of 80 subjects (39%) showing consistently low responses in AMLR (less than the mean--2 standard deviations of the healthy control group values) were designated low-AMLR patients, whereas the 42 patients (53%) who showed normal AMLR responses were designated normal-AMLR patients. However, there were no significant differences in the clinical parameters between these two groups of patients. The phenotypic analysis of T-cell fractions revealed a lower percentage of CD45RA-positive cells in CD4-positive cells (CD4+ CD45RA+ T cells) in the low-AMLR patients than those in normal-AMLR patients and healthy control subjects. No significant differences were demonstrated between the two groups in terms of the proportion of CD4-positive and CD8-positive cells in the T-cell fractions or in the expression of human leukocyte antigen DR of the monocytes and B cells in the non-T-cell fractions. In the low-AMLR patients, the allogeneic MLR was found to be normal, but the interleukin 2 production in the AMLR was found to be significantly depressed. The depressed AMLR responses and the lower percentage of CD4+ CD45RA+ T cells in the low-AMLR patients were found to be normalized following the periodontal therapy. These results might reflect changes in regulatory T-cell function induced by development of periodontal diseases.

The oxidative modification of low density lipoprotein by nonenzymatically glycated peptide-Fe complex

Glycated polylysine, a model of glycated peptide, produces Fe(3+)-chelated compound, which could be converted to an active form in a nonenzymatic process. The exposure of human low density lipoprotein (LDL) to the active glycated polylysine-iron complex caused lipid peroxidation significantly higher than LDL exposed to Fe3+, accompanied by formation of fluorescence compound in apoprotein B (Ex.max. 360 nm, Em.max. 435 nm). Highly modified LDL, which can be judged by an obvious increase of fluorescence compound, could be easily endocytized by rat peritoneal macrophages. alpha-Tocopherol or probucol possessed powerful inhibitory action against active glycated polylysine-iron complex-induced lipid peroxidation of LDL. Each of intrinsic proteins tested, such as apotransferrin, ceruloplasmin and albumin, at the concentration of normal levels of human blood or at the lower levels, also exhibited inhibitory action on the lipid peroxidation of LDL.

Cell membrane signaling as target in cancer therapy. II: Inhibitory effect of N,N,N-trimethylsphingosine on metastatic potential of murine B16 melanoma cell line through blocking of tumor cell-dependent platelet aggregation

Two phenotypic parameters, aberrant expression of protein kinase C and tumor cell-induced platelet aggregation (PA), have been correlated with abnormal growth behavior and metastatic potential of tumor cells. We recently observed that N,N,N-trimethylsphingosine (TMS) and N,N-dimethylsphingosine (DMS), but not sphingosine (SPN), had an inhibitory effect (via blocking of transmembrane signaling) on the growth of various human tumor cell lines in vitro as well as in vivo in nu/nu mice (K. Endo et al., Cancer Res., 51: 1613-1618, 1991). We therefore investigated the effects of TMS, DMS, and SPN on (a) PA induced by ADP and thrombin; (b) PA induced by melanoma cell line B16/BL6; and (c) experimental lung colonization as well as spontaneous lung metastasis of BL6 cells in syngeneic C57BL/6 mice. In experiments on agonist-induced PA, TMS inhibited PA and ATP secretion 5-fold more strongly than DMS or SPN. This effect may be based on the inhibition of Mr 47,000 platelet protein phosphorylation and/or inhibition of phosphatidylinositol turnover as a transmembrane signaling pathway in platelets. Tumor cell (BL6 melanoma)-induced PA and ATP secretion were also strongly inhibited by TMS, but not by DMS or SPN. Unlike ADP- or thrombin-induced PA, BL6 cell-induced PA was not inhibited by Calphostin-C (a potent protein kinase C inhibitor) or cilostazol (a potent inhibitor of PA based on inhibition of cyclic AMP phosphodiesterase). Since many previous studies suggested that the ability of tumor cells to induce PA is related to the degree of malignancy (e.g., metastatic potential) of tumor cells, we studied the effect of TMS on lung metastatic potential. Three independent sets of experiments, as described below, all showed clear inhibition of lung metastasis by administration of TMS: (a) i.v. coinjection of BL6 melanoma cells and TMS; (b) i.v. injection of TMS and, 1 h later, BL6 cells; (c) spontaneous metastasis to lung from s.c. BL6 tumor (TMS administered after establishment of tumor, followed by resection of tumor). In comparison to tumor growth inhibition produced by TMS or DMS, inhibition of melanoma metastasis by TMS is obvious at lower doses.

Evaluation of acridinium-ester-labeled DNA probes for identification of Mycobacterium tuberculosis and Mycobacterium avium-Mycobacterium intracellulare complex in culture

The detectability of mycobacteria in culture by the use of nonisotopic, chemiluminescent DNA probes for Mycobacterium tuberculosis and the M. avium-M. intracellulare complex (MAC) was evaluated and compared with that by the use of 125I-labeled DNA probes for the same mycobacteria. In the assay, rRNA-directed DNA probes labeled with acridinium ester (AE-DNA probes) were used. Unhybridized probes were chemically degraded, and the esterified acridinium on the hybridized probes was hydrolyzed by the addition of alkaline hydrogen peroxide solution, resulting in the production of visible light which was measured with a luminometer. The detection limits of the AE-DNA probes were almost the same as those of the 125I-labeled DNA probes. A total of 107 clinical isolates of mycobacteria (47 isolates of M. tuberculosis, 36 MAC, and 24 atypical mycobacteria other than MAC) were tested. The sensitivity and specificity of the AE-DNA probes for M. tuberculosis were 100% both for the conventional method and with the 125I-labeled DNA probe. The sensitivity and specificity of the AE-DNA probes for MAC were 97.2 and 100%, respectively, for the conventional method and were both 100% with the 125I-labeled DNA probes. Because the procedure is simple, reliable, rapid (it can be completed within an hour), and safe (it does not use radioisotopes), it can easily be performed in any clinical laboratory.

Three cases of acquired immunodeficiency syndrome complicated with toxic epidermal necrolysis

Co-trimoxazole (trimethoprim-sulfamethoxazole) and pyrimethamine-sulfadoxine have been recommended for treatment and prophylaxis, respectively, of Pneumocystis carinii pneumonia (PCP). However, toxic epidermal necrolysis (TEN) occurred in three of four patients with acquired immunodeficiency syndrome (AIDS) during the course of treatment or prophylaxis of PCP with these agents. On the other hand, 14 patients with PCP treated with pentamidine never developed TEN. Because the incidence of adverse skin reactions is higher among patients with AIDS than those without AIDS, and TEN is a severe, potentially fatal skin reaction, sulfonamide-containing drugs should be given cautiously to patients with AIDS.

[Diagnosis of acute aortic dissection with transesophageal echocardiography and results of surgical treatment]

Forty-four consecutive patients with acute aortic dissection from April 1987 to April 1990 were diagnosed with the use of transesophageal echocardiography (TEE) and treated at our institute. In 43 of them (98%, type A: 22 cases, type B: 21 cases), diagnosis was accurate and there were no complications. In one patient with type A dissection, the small intimal flap could not be detected. Emergency operations were performed in the patient with type A and ruptured type B. In type A, operated before cardiac arrest, the operative mortality rate was 20% (4/20). In ruptured type B, the operative mortality rate was 50% (2/4). The result of conservative therapy in the patient with nonruptured type B (17 cases) was satisfactory. The investigation by TEE was carried out without difficulty at the bed side and in the operating room as well, giving precise and rapid information and could be a useful diagnostic mean for acute aortic dissection.

[Urethral indwelling catheter, intermittent self-catheterization and urinary infection]

Once a catheter has been passed into the bladder without contamination, there are several possible routes of subsequent infection during drainage period, such as: 1. Entry of bacteria alongside the catheter in the urethra. 2. Introduced bacteria adhered easily to the indwelling catheter and drainage system and colonized. 3. The catheter tip is covered rapidly by various nutrient materials which becomes a good culture medium of stuck bacteria, which is a supply source of bacteria into the bladder urine. 4. Although the motile bacilli ascend very slowly through the stagnant tube and no bacteria ascend against a slowly moving column, rapid transport of organisms occurs in the swirling fluid caused by the passage of rising air bubbles. 5. Continuous urethral catheter drainage permits an average residual urine volume of 7.3 ml. 6. The catheter destroys the antibacterial defense mechanisms of the urinary bladder. The reasons why in many cases of intermittent self-catheterization (CID) urine becomes sterile despite non-sterile procedure, are as follows. In addition to that CIC has none of the disadvantages of the indwelling catheter, it improves the vesical defense mechanisms deteriorated by high pressure voiding. The number of bacteria reintroduced during catheterization is relatively small and they can be eradicated by usual scheduled catheterization within 4-5 hours without residual urine. CIC must be started before trabeculation or diverticuli are formed, in which bacteria remain. Actual determination of residual urine volume after catheterization will help to prescribe a rational program of CIC.

Emergency surgical intervention of acute aortic dissection with the rapid diagnosis by transesophageal echocardiography

Forty-five serial patients with acute aortic dissection were examined by transesophageal color Doppler echocardiography (TEE), and the diagnosis was made without aortography. No complications related to TEE occurred. Sufficient information for surgery was immediately obtained at the bedside by the TEE examination. Forty-four of 45 patients (98%) were diagnosed accurately, and 20 emergency operations for patients with type A aortic dissection and six emergency operations for patients with type B aortic dissection were performed. In only one patient, a small intimal flap in the ascending aorta was not detected by TEE. The operative mortality rate was 20% and 50% for types A and B aortic dissections, respectively. As a result of the progress of biplanar TEE technology, an easier and more accurate diagnosis of patients with acute aortic dissection can be achieved. The immediate and accurate diagnosis of acute aortic dissection can be achieved by TEE at the bedside, and treatment strategy can be more precisely determined.

[The parasympathetic direct pathway from the midbrain to the ciliary muscle in cats and monkeys]

The visceral, namely the parasympathetic component of the oculomotor complex which directly innervates ciliary muscle was investigated using horseradish peroxidase (HRP) in three cats and three monkeys. A unilateral total iridectomy to abolish innervation to the iris was made in all animals. After 1 month to allow fiber degeneration in the iris, HRP was injected into the ciliary muscle of ipsilateral eye. Distribution of the labeled cells at the midbrain and at the ciliary ganglion was examined. Labeled cells were present in the ciliary ganglion and midbrain in all three cats and three monkeys. In the cat, labeled cells were distributed in the Edinger-Westphal (EW) nucleus and the Perlia nucleus. In the monkey, labeled cells were distributed in the anteromedian (AM) nucleus, the EW nucleus and the Perlia nucleus, respectively. Therefore, the existence of a direct parasympathetic pathway from the midbrain to the ciliary muscles was confirmed in these animals. Based on these observations, it is obvious that accommodation of the eye was innervated partly by a direct pathway from the midsagittal region of the parasympathetic neuron of the oculomotor nuclear complex.

Diagnosis of Pneumocystis carinii pneumonia by 5S ribosomal DNA amplification

The polymerase chain reaction technique was used to detect Pneumocystis carinii by amplifying the P. carinii 5S ribosomal DNA. The efficacy and specificity of this diagnostic method is reported. Analysis of patients' sputa indicate that the method can be used on these samples for the diagnosis of P. carinii pneumonia.

Anticoagulant heparin-like glycosaminoglycans on endothelial cell surface

Atherosclerosis is associated with an accumulation of proteoglycans. Proteoglycans and/or glycosaminoglycans, in particular heparan sulfate, produced by endothelial cells are thought to play important roles in diverse vascular functions. Of particular note is that they possess anticoagulant functions, i.e., heparin-like antithrombin cofactor activity. Incubation of antithrombin III with endothelial cell cultures resulted in a specific, saturable binding of this protease inhibitor presumably to the endothelial cell surface. In addition, thrombin inactivation by antithrombin III was accelerated on the endothelial surface, providing strong evidence that heparan sulfate on the surface of endothelial cells exerts a heparin-like activity. beta-D-xyloside or cytokine treatments altered the synthesis of heparan sulfate on the endothelial cell surface, resulting in decreased anti-thrombin III binding and diminished heparin-like anticoagulant activity of endothelial cells. The modulation of endothelial heparin-like compounds by these pharmacologic or physiologic agents may have pathophysiologic implications in thrombosis as well as atherogenesis.

Binding to opioid receptors of enkephalin derivatives taking alpha-helical conformation and its dimer

The opioid receptor binding of [Leu]enkephalin derivatives with extended address segment to the C-terminal was studied. The extension peptide is designed to take an amphiphilic helical structure in order to evaluate effects of helical conformation and membrane affinity of enkephalin moiety of the derivatives on receptor binding. In the delta-receptor-selective binding assay, Tyr-Gly-Gly-Phe-Leu-Lys-Aib-Leu-Aib-OH (1) showed the same affinity as enkephalinamide, whereas in the mu-receptor-selective binding assay, a 7-fold reduction in affinity was observed. On the other hand, Tyr-Gly-Gly-Phe-Leu-(Lys-Aib-Leu-Aib)2-OH (2) showed 51- and 96-fold decreases in affinities for delta- and mu-receptors, respectively, compared with enkephalinamide. The low receptor affinity of derivative 2 is considered due to alpha-helical conformation, which might not be compatible with topological requirements of delta- and mu-receptors. A dimer, Tyr-Gly-Gly-Leu-Phe-(Lys-Aib-Leu-Aib)2-Lys(X)-Aib-OCH3 (X = Tyr-Gly-Gly-Phe-Leu-, (4], showed 2.5- and 3.0-fold increases in affinities respectively for delta- and mu-receptors compared with the monovalent derivative 2, possibly due to cross-linking of neighboring receptors. The Hill plot of the binding of the dimer to bovine brain membranes was composed of two phases, although such a heterogeneity of receptors was not observed in the presence of naloxone or in the binding to NG108-15 cell membranes. These findings indicate the presence of the bivalent-ligand-induced interactions between delta- and mu-receptors in bovine brain membranes.

Characteristics of binding of endothelin-1 and endothelin-3 to rat hearts. Developmental changes in mechanical responses and receptor subtypes

Endothelin-1 (ET-1) and endothelin-3 (ET-3) produced positive inotropic effects on electrically stimulated left atria and increased the frequency of spontaneously beating right atria of adult rats. The potency of the inotropic effect of ET-1 was greater than that of ET-3, but the potencies of the chronotropic effects of ET-1 and ET-3 were not significantly different. In the neonatal atria, ET-1 and ET-3 also induced positive inotropic and chronotropic responses. ET-1 and ET-3 showed weak or no cardiotonic effects on the adult ventricles, whereas they caused marked positive inotropy in the neonatal ventricles. The characteristics of binding sites for ET-1 and ET-3 were very similar between the atria and the ventricles of the rat neonate. Saturation and competition binding experiments have shown that neonatal cardiac membranes from both atria and ventricle have two distinct binding sites for endothelin, that is, a low-affinity and a high-affinity site. ET-1 was found to bind to the low-affinity sites with a significantly lower Kd than ET-3, whereas the estimated Kd values for ET-1 and ET-3 at the high affinity sites were similar. In contrast, the binding sites in adult atria were different from those of the ventricles: only a single binding site for both ET-1 and ET-3 was detected. Adult atrial membranes, on the other hand, had two distinct binding sites similar to those of neonatal membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

Post-mortem diagnosis of human T lymphotrophic virus type-1 (HTLV-1) associated myelopathy by detection of HTLV-1 DNA in the spinal cord of a patient with post-transfusional myelopathy

Human T lymphotrophic virus type-1(HTLV-1) is thought to be an etiological agent of HTLV-1 associated myelopathy (HAM). Therefore, a definitive diagnosis of HAM can not be made if information on the presence of antibody against HTLV-1 is not available, even though clinical and histopathological features strongly indicate the disease. In this study, HTLV-1 DNA was detected in the formalin-fixed, paraffin-embedded spinal cord of an autopsy case with post-transfusional myelopathy using the polymerase chain reaction (PCR). Ante-mortem HAM was not suspected of and the antibody has not been examined. Neuropathological examination of the sequential sections revealed a loss of axons and myelin sheaths in the white matter, resembling the histopathology of HAM. The post-mortem detection of HTLV-1 DNA by PCR may be useful for the confirmation of HAM in cases which were not provided with appropriate clinical data.

Isolation and characterization of 1,200 kDa peptide of alpha-connectin

When rabbit skeletal muscle myofibrils were kept for 12 h at 4 degrees C, alpha-connectin was partially degraded and 1,200 kDa peptide was newly formed [Takahashi, K. & Takai, H. (1988) Abst. 80th Jpn. Soc. Zootech. Sci. p-102]. The latter was isolated together with remaining alpha-connectin. Ultracentrifugation of the mixture at low ionic strength resulted in sedimentation of alpha-connectin, leaving the 1,200 kDa peptide in the supernatant. Physicochemical properties of the isolated 1,200 kDa peptide were investigated: UV absorption spectra, circular dichroism spectra, amino acid composition, and molecular size and shape. Polyclonal antibodies against the 1,200 kDa peptide [PcAb(1200)] bound the Z line and I-band. The position of the stripe in the I band near the N1 line due to the binding of PcAb(1200) moved both away from the Z lines and from the A band as sarcomeres were elongated. Therefore, it is considered that the 1,200 kDa portion of alpha-connectin is elastic.

Thyroid-specific enhancer-binding protein (T/EBP): cDNA cloning, functional characterization, and structural identity with thyroid transcription factor TTF-1

A cDNA clone encoding a thyroid-specific enhancer-binding protein (T/EBP) was isolated from a rat thyroid-derived FRTL-5 cell lambda gt 11 expression library, using a double-stranded oligonucleotide probe. This oligonucleotide was previously demonstrated to have the strongest binding affinity among three cis-acting DNA elements within the thyroid-specific enhancer region located 5.5 kbp upstream of the human thyroid peroxidase gene transcription start site. Nucleotide and deduced amino acid sequences of the cDNA revealed that T/EBP is identical to the previously reported thyroid-specific transcription factor 1 (TTF-1), which binds to the promoter of the rat thyroglobulin gene and controls its thyroid-specific expression. Expression of the T/EBP cDNA under control of the human cytomegalovirus major immediate-early gene promoter conferred thyroid-specific enhancer activity of as high as 26-fold to nonpermissive human hepatoma HepG2 cells when cotransfected with a vector containing 6.3 kbp of upstream sequence of the human thyroid peroxidase gene connected to a luciferase reporter gene. T/EBP was further expressed in HepG2 cells by using the vaccinia virus expression system. The expressed protein was partially purified by using sequence-specific affinity column chromatography and was further shown, by gel mobility shift experiments, to specifically bind to the enhancer-derived double-stranded oligonucleotide. These results clearly indicate that the binding of T/EBP (TTF-1) to the specific cis-acting enhancer element is largely responsible for thyroid-specific enhancer activity.

Factors associated with silent multiple lacunar lesions on magnetic resonance imaging in asymptomatic elderly hypertensive patients

1. Factors associated with advanced cerebrovascular damage incidentally seen on brain magnetic resonance imaging (MRI) were investigated in a population of 34 normotensive and 54 hypertensive asymptomatic elderly individuals (69 +/- 5 years). 2. Four or more 'lacunar' lesions per subject were considered to be advanced changes, based on the distribution in normotensive subjects and were found in 11 (20%) out of 54 hypertensive subjects. 3. Compared with the remaining 43 hypertensive patients with fewer or no lacunae, the proportion of subjects over 70 years of age who had electrocardiographic (ECG) evidence of left ventricular hypertrophy (LVH) was significantly higher in this group of hypertensive patients. Patients with multi-lacunar lesions also showed significantly higher 'office' and average ambulatory, in particular, blood pressure during sleep and less nocturnal blood pressure fall, than those with fewer or no lacunae. Furthermore, they showed a higher predicted whole blood viscosity and a lower high density lipoprotein (HDL)-cholesterol. The predictive values of LVH on ECG for the presence of multi-lacunar lesions in hypertensive patients were substantially high (70-90%). 4. The data suggest that silent advanced cerebrovascular damages on MRI are not rare among asymptomatic elderly hypertensive patients and are associated with various cerebrovascular risk factors. A useful marker for their identification appears to be ECG-LVH.

Effect of H+ on ATP-regulated K+ channels in feline ventricular myocytes

Using patch-clamp techniques, we examined the effects of pH on properties of ATP-regulated K+ channels in single myocytes isolated from cat left ventricles. ATP-K+ channels of inside-out patches were bilaterally exposed to 140 mM K+ solutions (22 degrees C). In the absence of ATP and Mg2+, the channels had a linear current-voltage relationship during hyperpolarizing pulses (20-100 mV negative to the reversal potential) at both intracellular pH (pHi) 7.4 and 6.5, but the slope conductance was 66 +/- 2 pS at pHi 7.4 and 46 +/- 2 pS at pHi 6.5. Lowering pHi from 7.4 to 6.5 increased the mean open time (from 15.9 +/- 4.6 to 35.9 +/- 7.9 ms, P less than 0.01) but decreased the open-state probability measured at 50 mV positive to the reversal potential (from 0.35 +/- 0.04 to 0.16 +/- 0.04, P less than 0.01). However, in the presence of both 0.2 mM ATP and 1 mM MgCl2, lowering pHi from 7.4 to 6.5 increased the mean open time (from 5.0 +/- 2.6 to 17.9 +/- 5.9 ms, P less than 0.01) and the open-state probability (from 0.025 +/- 0.010 to 0.098 +/- 0.024, P less than 0.01). These data indicate that increases in intracellular H+ concentration modulate cardiac ATP-K+ channel properties. Ischemia-associated decreases in pHi may enhance the opening of cardiac ATP-regulated K+ channels and resultant action potential shortening.

[Three cases of intramural cyst of the esophagus with ciliated epithelium]

We had 3 cases of intramural cyst of the esophagus with ciliated epithelium. In Case 1, 13-year-old man, the cyst was lined with ciliated columnar epithelium and had a smooth muscle layer. In Case 2, 37-year-old female, the cyst was lined with ciliated stratified epithelium and had some layers of smooth muscle. In Case 3, 42-year-old male, the cyst was lined with ciliated columnar epithelium and had a smooth muscle layer. In all cases, cartilaginous tissue was not found. They had no complaints and the abnormal shadow was found by chance Chest X-ray film. When the cyst did not have typical diagnostic criteria, clear division into esophageal cyst or bronchogenic cyst is difficult. The bronchus and the esophagus are of the foregut origin, so we suppose the middle type cyst, between esophageal and bronchial, may exist. In Case 2, the cyst was diagnosed as esophageal, because it had some muscle layers. But in Case 1 and Case 3, as the cyst did not have typical diagnostic criteria, we diagnosed them as the inclusion cyst of the esophagus, not as esophageal, not as bronchogenic.