Comparison of fecal microflora of elderly persons in rural and urban areas of Japan

The Fecal microflora of 15 healthy elderly persons with a median age of 84 years in a rural area whose inhabitants tend to be long-lived (Yuzurihara-area, Uenohara, Yamanashi Prefecture) was compared with the microflora of individuals with a median age of 68 years in an urban area (Tokyo). The diet of the elderly persons in the Yuzurihara area is characterized by a high intake of dietary fiber. Total numbers of anaerobic bacteria were significantly smaller in the elderly persons in the Yuzurihara area than those in the Tokyo area. A significantly large number of bifidobacteria, but not of lecithinase-negative clostridia, was observed in the elderly persons in the Yuzurihara area. Large numbers and high incidences of bacilli and lecithinase-positive clostridia (mainly Clostridium perfringens) were found in the elderly persons in the Tokyo area. Twenty-five genera and over 81 species were isolated from the elderly persons in the Yuzurihara area, and 25 genera and over 92 species were isolated from the elderly persons in the Tokyo area. Furthermore, significantly larger numbers of Bifidobacterium adolescentis and Fusobacterium mortiferum strains were found in the Yuzurihara group, but significant reductions in the Bacteroides buccae-oris group, B. thetaiotaomicron, Bacteroides spp., C. coccoides, C. paraputrificum, and Clostridium spp. were observed in the same group. A significantly higher isolation rate of Bacillus subtilis was observed in the elderly persons in the Tokyo area. The difference in the fecal microflora between elderly persons in Yuzurihara and those in the Tokyo area might be due to a difference in the intake of dietary fiber.

Growth characteristics of Tyzzer's organism in cultured mouse hepatocytes

The growth characteristics of Tyzzer's organisms in cultured mouse hepatocytes were examined by direct bacterial counting and plaque assay. The viability of propagated bacteria and time required for the maximum titers depended on incubation time and inoculum dose, respectively. Both infectious titers and bacterial counts at optimum harvests were much higher than those obtained from infected mouse livers. Immunofluorescence revealed, after a lag phase of about 2 h, a linear multiplication during a 6 h period.

Effect of rice fiber on human fecal microflora

The effects of brown rice, containing fourfold as much dietary fiber as polished rice, on the human fecal microflora were determined. Significantly increased numbers of Bifidobacterium adolescentis and Enterococcus faecalis were observed during the brown rice intake, whereas the total counts and the numbers of bacteroides, Eubacterium aerofaciens, and Escherichia coli during the intake were lower than those before and after the intake. Lower numbers of clostridia and low incidences of Clostridium paraputrificum and C. perfringens were observed during the brown rice intake.

Changes in T wave morphology during hypercalcemia and its relation to the severity of hypercalcemia

The effect of hypercalcemia on T wave morphology, polarity, and amplitude was studied in 14 patients with a primary diagnosis of malignant lymphoma (8 patients), adult T-cell leukemia (5 patients), and Hodgkin's disease (1 patient). Hypercalcemia was severe to extreme in 11 (14.9-22.8 mg/dl), moderate in 1 (13.4 mg/dl), and mild in 2 (11.8 and 12.2 mg/dl) patients. Ten of the 11 patients (91%) with severe hypercalcemia showed inverted, biphasic, and notched T waves, mainly in the chest leads. Notched T waves were observed in all 10 of these patients in anterior to lateral, mid to lateral, or lateral chest leads. Biphasic and/or inverted T waves in anterior or anterior to midchest leads were present in 4 of these 10 patients who had extreme hypercalcemia (greater than 16 mg/dl). Changes in T wave morphology were not observed in moderate or mild hypercalcemia. T wave amplitude showed significant inverse correlation with serum calcium (T mV vs Ca, r = -0.60, p less than 0.001; T/R ratio vs Ca, r = -0.68, p less than 0.001; n = 35). Decrease in T wave amplitude was marked in severe hypercalcemia (p less than 0.0001) and moderate hypercalcemia, but there was no change in mild hypercalcemia. Changes in T wave morphology, polarity, and amplitude either appeared with development of hypercalcemia or disappeared with normalization of serum calcium level. It was concluded that in addition to shortening the QT interval, severe to extreme hypercalcemia can cause development of inverted, biphasic, or notched T wave with a marked decrease in amplitude of T waves.

Effects of chronic hypokalemia on ventricular vulnerability during acute myocardial ischemia in the dog

Chronic hypokalemia (2.9 +/- 0.2 mEq/L) was induced in 10 dogs by a low potassium diet and furosemide administration. Five control dogs with normokalemia (5.0 +/- 0.3 mEq/L) were fed an ordinary diet. Three of the 10 hypokalemic dogs had electrically induced, nonsustained ventricular tachycardia (NSVT) and ventricular fibrillation (VF); none of the 5 control dogs had these ventricular arrhythmias. After ligation of the left anterior descending coronary artery (LAD), 4 of the 10 hypokalemic dogs developed spontaneous VF and 6 had electrically induced NSVT and VF, whereas 2 of the 5 control dogs had only NSVT. The effective refractory period (ERP) of the ventricles of the hypokalemic dogs was slightly longer than that of the control dogs. After LAD ligation, only the ERP of the anterior wall of the left ventricle was prolonged significantly in either group (p less than 0.01). The ventricular fibrillation threshold (VFT) of hypokalemic dogs was significantly lower than the control dogs (p less than 0.05), and was reduced markedly (p less than 0.05) after LAD ligation. A positive correlation between VFT and serum potassium level was observed. Thus, chronic hypokalemia increases ventricular vulnerability. This effect depends upon the severity of hypokalemia and is markedly augmented by acute myocardial ischemia. These findings indicate that, in clinical settings, preexisting hypokalemia and its severity may play important roles in the occurrence of lethal ventricular arrhythmias during the acute phase of myocardial infarction.

Experimental encephalomyocarditis virus infection in Mongolian gerbils (Meriones unguiculatus)

Two strains of Mongolian gerbils (Meriones unguiculatus), Tumble Brook (TUM) and Japan Medical Science (JMS), were intraperitoneally inoculated with the D variant of encephalomyocarditis virus (EMC-D) and killed 3 days later. Mortality was significantly higher in females than in males. Evidence of viral replication was detected in the heart of both strains and in the pancreas of the TUM strain. Histopathological alterations were found in the heart and pancreas. Heart lesions involved foci of necrosis with inflammatory cell infiltration and calcification in both strains. Pancreatic lesions were restricted to the exocrine glands; islets of Langerhans were rarely and secondarily involved in the extensive destruction of exocrine glands. Severe acinar cell necrosis with marked inflammatory edema was conspicuous in TUM, whereas only slight acinar cell involvement was detected in JMS gerbils. Immunoperoxidase staining showed viral antigens in intracytoplasmic vacuoles in damaged acinar cells.

Gastrointestinal flora of cotton rats

The gastrointestinal (GI) flora of cotton rats was examined. No lactobacilli were detected in any part of the GI tract. Anaerobes, including Peptococcaceae, Bacteroidaceae, bifidobacteria and eubacteria, were the predominant bacteria in the stomach, small intestine, caecum and faeces. Aerobes and facultative anaerobes, including Enterobacteriaceae and streptococci, were detected at low numbers and very low frequency of occurrence in all parts of the GI tract. Sixty-one isolates of bifidobacteria were recovered from the stomach, small intestine, caecum and faeces of cotton rats. They were identified as Bifidobacterium animalis, B. pseudolongum biovar a and b. The study showed that the GI flora of cotton rats seem to be very different from the GI flora in other rodents.

Initial lesions in the mouse brain induced by intraperitoneal injection of hypertonic saline

A dose of 30 ml/kg of 8.5% solution of sodium chloride was intraperitoneally injected into ddY mice and time course observations were conducted. Colloidal carbon was infused 6 hr after injection and distribution of carbon in the brain was observed. A transient increase in hematocrit value, serum osmotic pressure and ascites was observed 1 hr arter injection. Distribution of colloidal carbon in the brain showed less penetration of the basal ganglia. Histopathological examination of the brain showed degeneration of pyramidal cells in hippocampus 6 hr after injection. Electron microscopical examination revealed intracytoplasmic microvacuoles, swollen mitochondria and dilated cisternae in rough-surfaced endoplasmic reticulum of pyramidal cells. It was suggested that serum viscosity was increased by rapid transport of water from blood into the peritoneal cavity or urine, due to the high osmotic pressure of hypertonic saline injected, resulting in a decrease in blood flow and ischemic changes in the brain.

Behavioral characteristics in mice with brain lesions induced by hypertonic saline

Behavioral and histopathological characteristics were studied in mice treated repeatedly with hypertonic saline. In passive avoidance response using a step-through-type shuttle box, the mice treated with hypertonic saline showed shorter latency than control mice. No changes were observed in active avoidance response using a two-way-type shuttle box, spontaneous motor activity or motor function. Histopathological examination revealed marked and frequent degeneration and loss of neurons in the hippocampus as compared with animals after single treatment. The animals with severe hippocampal lesions showed impairment of passive avoidance response. The present brain lesions resulting from repeated treatment with hypertonic saline in mice are considered to be a possible model for memory disorders caused by hippocampal lesions in humans.

Benefits of dual chamber pacing in sick sinus syndrome

The effects of DDD (fully automatic) and VVI (ventricular demand) pacing modes on exercise tolerance, symptom diary cards, and Holter monitoring were investigated in a randomised double blind crossover study of 16 patients who had had DDD pacemakers implanted because of frequent syncope. Eight patients presented with sick sinus syndrome and, with one exception, retrograde atrioventricular conduction and eight age and sex matched patients presented with 2:1 or complete atrioventricular block. Maximal symptom limited exercise in those with atrioventricular block was significantly higher after one month of DDD pacing than after VVI pacing. In those with sick sinus syndrome, however, maximal effort tolerance was not significantly different for the two pacing modes. In all but one patient with sick sinus syndrome sinus rhythm developed during exercise in VVI pacing. For both VVI and DDD modes maximal atrial rates were significantly lower in those with sick sinus syndrome. Palpitation and general wellbeing were significantly improved during DDD pacing in the eight patients with sick sinus syndrome. Shortness of breath was improved by DDD pacing in the eight patients with atrioventricular block but not in those with sick sinus syndrome. Holter monitoring showed that sick sinus syndrome patients remained in paced rhythm, either DDD or VVI, for most of the 24 hour period. DDD pacing was better than VVI pacing in sick sinus syndrome with retrograde atrioventricular conduction. Despite their ability to show sinus rhythm and inhibit their pacemakers on exercise patients with sick sinus syndrome are just as likely to have symptomatic benefit from DDD pacing as patients with atrioventricular block.

Histopathology of BALB/c mice infected with the D variant of encephalomyocarditis virus

BALB/c mice infected with 10(5) pfu of the D variant of encephalomyocarditis virus were examined histopathologically during the subacute stage of infection. Main pathologic changes were observed in the brain, heart (massive myocardial necrosis with subsequent organization (i.e., replacement of necrotic myocardium by connective tissue) and congestion and dilatation of the right ventricle) and pancreas (moderate degranulation of beta-cells resulting in elevation of blood glucose level). The brain lesions were found most frequently in the pyramidal layer of the hippocampus and the granular layer of the cerebellum and were characterized by degeneration of neurons containing virus antigens. Perivascular mononuclear cell infiltration, spreading to the adjacent brain tissue, and thrombosis in small vessels were also frequently seen. Focal loss of neurons and gliosis developed later in these lesions.

Effect of dietary phenobarbital on spontaneous hepatic tumorigenesis in germfree C3H/He male mice

Phenobarbital (PB) is known to be a promoter of liver tumorigenesis in rats and mice. The present study was designed to examine the effect of PB on liver tumorigenesis in C3H/He germfree (Gf) male mice. Gf and conventional (Cv) animals were given an irradiated (5 Mrad) basal diet containing 200 ppm PB from 6 weeks old until termination of the experiment. When they were 12 months old, the animals were killed under CO2 inhalation and autopsied for the number and size of tumor nodules. The incidence of liver tumors was significantly higher in PB-fed Gf animals (67%) than in non-treated Gf controls (30%), and higher in PB-fed Cv animals (100%) than in non-treated Cv controls (75%). The number of tumor nodules per mouse was also significantly higher in PB-fed Gf animals (2.0) than in non-treated Gf controls (0.4), and higher in PB-fed Cv animals (4.5) than in non-treated controls (1.3). The present study demonstrated that dietary PB induced increases in number of the tumor nodules and decreases in the tumor size of C3H/He mice.

Genetic control in the susceptibility of germfree inbred mice to infection by Escherichia coli O115a,c:K(B)

We studied the susceptibility of five germfree inbred strains of mice to oral infection by murine pathogenic Escherichia coli O115a,c:K(B) (MPEC), the causative agent of mouse megaenteron. Although MPEC colonized all strains of mice at 10(9)/g of feces, the mouse strains could be divided into three groups according to their intestinal lesions. In CF1 and C3H/He mice, intestinal lesions were produced in the cecum and colon with hyperplasia of epithelial cells accompanied by severe inflammatory reactions and erosion. The lesions in NC and C57BL/6 mice were restricted to the tip of the cecum, and hyperplasia of epithelial cells was more severe in these mice than in CF1 or C3H/He mice. BALB/c mice had no lesions. Analysis of F1 hybrids of CF1, NC, and BALB/c mice and offsprings from backcrosses of F1 mice to parental strains showed that susceptibility to MPEC seemed to be controlled genetically by a single locus which may be related to the receptors on epithelial cells for MPEC adherence. However, the differences in lesions between CF1 and NC mice suggest that a combination of this locus and another locus to which it may be related regulates the hyperplasia of intestinal epithelial cells.

Brain lesions induced by hypertonic saline in mice: dose and injection route and incidence of lesions

A single injection of hypertonic saline produced brain lesions with corresponding nervous signs in mice. The lesions were most often found in the hippocampus and were characterized by degeneration and loss of pyramidal cells. They could be induced effectively by a single administration of 20 ml of 25% saline/kg orally or of 30 ml of 8.5% saline/kg intraperitoneally. This simple experimental system seems to be a useful model of central nervous system involvement.

Histochemical characteristics of glycoproteins in the bile duct system of mice immunized with swine serum

The bile duct system of BALB/c and DDY mice, which were immunized with swine serum (SS) or not, was examined histochemically. Biliary epithelial cells of the SS-treated BALB/c mice, which were positively stained with periodic acid-Schiff (PAS) and had binding sites of Dolichos biflorus (DBA), were thought to secrete neutral glycoproteins with terminal N-acetyl-D-galactosamine residues. Those of the SS-treated DDY mice were however negatively or weakly stained with any histochemical stainings. On the other hand, glandular epithelial cells of the SS-treated mice of both strains, which were positively stained with high iron diamine-alcian blue (HID-AB) and had binding sites of DBA, Griffonia simplicifolia-II (GS-II), Ulex europaeus-I (UEA-I), and Triticum vulgaris (WGA), were thought to secrete glycoproteins with terminal sialic acid residues. Biliary and glandular epithelial cells of the normal mice contained only a small amount of glycoproteins showing similar histochemical characteristics to those in the SS-treated BALB/c mice. BALB/c mice immunized with SS were thought to be very useful for the investigation of production and secretion of glycoproteins in the bile duct system as well as being good model of bile duct disease.

Interacting negative chronotropic effects of adenosine and the vagus nerve on the canine sinus node

The vagus nerve and adenosine exert a negative chronotropic effect on the mammalian sinus node. In addition, adenosine is released from myocardial cells under both physiological and pathophysiological conditions, which are characterised by variable vagal tone. To determine the interaction between adenosine and the vagus nerve, 21 barbiturate anaesthetised mongrel dogs with bilateral cervical vagotomy and stellectomy were studied. In group 1 (n = 16) adenosine (3 mumol.kg-1) was rapidly (less than or equal to 1 s) administered before (control) and during 60 s of repetitive vagal stimulation. Each stimulus (consisting of a burst of 5 square wave pulses, 0.3 mA in amplitude and 1 ms in duration at 0.1 kHz) was given at a fixed point in time in each sinus cycle (that is, one burst per cycle). This protocol was repeated after a 50 ms incremental change in the phase at which vagal stimulation was given until the entire cycle length was scanned. Recovery time of at least 2 min separated any two consecutive adenosine administrations. In four animals the above protocol was performed twice using vagal stimulation amplitude of 0.3 mA and 0.6 mA in the first and second runs respectively. In this group (group 1), the effect of adenosine was altered by the vagus in a phase dependent manner. In each animal, however, there was at least one phase of the sinus cycle during which vagal stimulation significantly enhanced the effect of adenosine.(ABSTRACT TRUNCATED AT 250 WORDS)

Early ultrastructural changes in the biliary epithelial cells of BALB/c and DDY mice immunized with swine serum

Electron microscopic observations were carried out on the biliary epithelial cells of BALB/c and DDY mice which had received an intraperitoneal injection of 0.2 ml of swine serum twice a week for 2 or 4 weeks. The most characteristic feature of the biliary epithelial cells of BALB/c mice was a marked increase in the number of vesicles having a close spatial relationship with the well-developed Golgi apparatus or rough endoplasmic reticulum (rER). In contrast, marked dilation of rER filled with moderately electron-dense material was conspicuous in the biliary epithelial cells of DDY mice. A prominent increase in the number of blebs and lateral and basal cytoplasmic protrusions in the dilated intercellular space of the biliary epithelium, and submucosal eosinophil infiltration, collagen fiber proliferation and gland hyperplasia with increased mucin secretion were common to both strains. This experimental model of bile duct disease also seems to be useful for investigating alteration of protein synthesis and secretion in epithelial cells.

Influence of collateral flow reduction on electrophysiologic properties of preexisting ischemic area and inducibility of ventricular arrhythmias in the dog

Electrophysiologic properties of the left ventricle, vulnerability to ventricular arrhythmias and regional myocardial blood flow (RMBF) of the left ventricle were examined during superposition of acute ischemia on a healed myocardial infarction. The left circumflex coronary artery (LCX) was ligated in 13 dogs with a 28-day-old anteroapical infarction. Six (46%) of 13 dogs had reproducible ventricular tachycardia in response to programmed ventricular stimulation before LCX ligation. Ventricular fibrillation could be induced in 2 of these 6 dogs. After LCX ligation, 11 (85%) of 13 dogs had ventricular arrhythmias induced by ventricular stimulation. Nine of 13 dogs had ventricular tachycardia and 7 of 13 dogs had ventricular fibrillation. The heterogeneity of the effective refractory period (delta ERP) and the local intraventricular conduction time (LIVCT) in the border and the infarct zones of the left ventricle increased significantly after LCX ligation. RMBF in the border and the infarct zones were markedly decreased by LCX ligation. The magnitude of reduction of RMBF was correlated significantly with the prolongation of LIVCT. In conclusion, acute critical reduction of the collateral blood supply causes a more heterogeneous refractory period and conduction delay in the preexisting ischemic area of the heart, increasing the vulnerability to lethal ventricular arrhythmias.