Chronic hypertension induced by streptozotocin in rats

An intravenous injection of 40 or 65 mg/kg streptozotocin induced not only diabetes but also severe hypertension in rats. Whereas the hyperglycemia developed fully within a few days after the injection of streptozotocin, the hypertension progessively advanced and reached maximum level several weeks after the treatment and lasted more than 20 weeks. Twenty mg/kg streptozotocin did not induce hyperglycemia but significantly increased blood pressure several weeks after the treatment. Arrest of growth, polyuria, glycosuria, hyperlipemia and lenticular cataracts developed in the animals treated with 40 or 65 mg/kg streptozotocin, but in none of the animals treated with 20 mg/kg. In histological examinations in the 24th week after the treatment, degranulation and necrosis in the pancreatic beta-cells, and vacuolization and deposition of PAS-positive materials in the renal proximal tubules were found in the animals treated with 40 or 65 mg/kg streptozotocin.

Frequency of intrahepatic arteriovenous fistula as a sequela to percutaneous needle puncture of the liver

Incidence of intrahepatic arteriovenous fistula after needle biopsy of the liver, percutaneous transhepatic cholangiography, and transhepatic catheterization of an intrahepatic bile duct or portal vein, was determined by studying the hepatic arteriograms obtained within 1 month of the transhepatic procedure. An arteriovenous fistula, mostly arterioportal, occurred in 5 (5.4%) of the 93 patients after biopsy, in 3 (3.8%) of 79 after percutaneous transhepatic cholangiography, and in 7 (26.2%) of 26 after catheterization. None of the fistulae was so large and close to the porta hepatis as to cause portal hypertension. In 1 patient with an intrahepatic bile duct carcinoma, the long track of a 0.7-mm caliber needle became a fistula draining arterial blood into the parenchyma. In another, an aneurysm was found after biopsy and percutaneous transhepatic cholangiography. The possibility of spontaneous closure of small fistulae is discussed.

Behavior of a vigorous alpha- or beta-hemolysin-producing strain of Staphylococcus aureus in the cutaneous tissue of mice

Two strains of Staphylococcus aureus were examined for behavior in the cutaneous tissue of mice by the fluorescent antibody technique, hematoxylin and eosin staining. When about 10(8) viable cells of an alpha-hemolysin-producing strain (Wood 46) were inoculated subcutaneously into a mouse, they multiplied in the subcutaneous tissue of the mouse and gradually entered the corium to produce alpha-hemolysin and nuclease. Edematous and necrotic lesions were observed in the cutaneous tissue where the organisms had multiplied. When 10(8) viable cells of a beta-hemolysin-producing strain (Kitami 3-9D) were inoculated into a mouse, they multiplied within a narrow extent surrounded mainly by infiltrating leukocytes and produced mainly beta-hemolysin. The changes of cutaneous tissue were weaker in mice inoculated with Kitami 3-9D strain than in mice inoculated with strain Wood 46. When 10(6) viable cells of both strains were inoculated into mice, they were phagocytized by leukocytes. Neither multiplication of organisms nor production of any active extracellular substance was observed in these mice. Edema, degeneration, and necrosis were also noticed in the cutaneous tissue of mice inoculated with alpha- and beta-hemolysin. In addition, the infiltration of leukocytes was inhibited mainly by alpha-hemolysin.

Membrane particle aggregates in innervated and noninnervated cultures of Xenopus embryonic muscle cells

Clusters of membrane particle aggregates were found in the cultures of Xenopus embryonic muscle cells. In innervated cultures, the aggregates were usually found in the vicinity of the nerve. In terms of particle density and morphology, they resembled the postsynaptic particle aggregates of adult skeletal muscle fibers, suggesting that they may be related to acetylcholine receptors. Similar particle aggregates were also found in noninnervated cultures. They may correspond to extrajunctional clusters of acetylcholine receptors or "hot spots."

Clinicopathologic features of encapsulated hepatocellular carcinoma: a study of 26 cases

The clinicopathologic features of 26 cases of hepatocellular carcinoma (HCC) surrounded by a grossly distinct capsule-like fibrous tissue were studied. The frequency of this type was 10.3% among autopsy cases of HCC. The mean age of the patients was 64.1 years, which was significantly older compared with that of 143 cases of nonencapsulated HCC. Hepatitis-B surface antigen in serum was positive in 18.7% of the cases studied, the positivity rate being lower than that of HCC in general. Histologically, the tumor was relatively well differentiated and the capsule was the product of slow expanding growth. Intravenous tumor invasion was less frequent compared with other types of HCC. Clinically, celiac angiography proves to be a most useful diagnostic method; a thick capsule may be demonstrated as a thin radiolucent rim around the mass. The clinical course from the early stage is protracted and, if detected early, this type of HCC may be removed surgically.

Clinicopathologic features of encapsulated hepatocellular carcinoma: a study of 26 cases

The clinicopathologic features of 26 cases of hepatocellular carcinoma (HCC) surrounded by a grossly distinct capsule-like fibrous tissue were studied. The frequency of this type was 10.3% among autopsy cases of HCC. The mean age of the patients was 64.1 years, which was significantly older compared with that of 143 cases of nonencapsulated HCC. Hepatitis-B surface antigen in serum was positive in 18.7% of the cases studied, the positivity rate being lower than that of HCC in general. Histologically, the tumor was relatively well differentiated and the capsule was the product of slow expanding growth. Intravenous tumor invasion was less frequent compared with other types of HCC. Clinically, celiac angiography proves to be a most useful diagnostic method; a thick capsule may be demonstrated as a thin radiolucent rim around the mass. The clinical course from the early stage is protracted and, if detected early, this type of HCC may be removed surgically.

Antihypertensive effect of combined treatment with alpha- and beta-adrenergic blockers in the spontaneously hypertensive rat

Using a continuous systolic monitor, effects of oral administration of three alpha-adrenergic blockers, i.e. phenoxybenzamine, phentolamine and a new quinazoline compound (2-[4-(n-butyryl)-homopiperazine-1-yl]-4-amino-6, 7-dimethoxy-quinazoline; E-643), on blood pressure and heart rate in normotensive Wistar rats (NWR) and spontaneously hypertensive rats (SHR). 1) An oral dose of 1 mg/kg phenoxybenzamine or E-643 almost completely reversed pressor response to adrenaline (2 microgram/kg i.v). Phentolamine was 3 to 5 times less effective than phenoxybenzamine and E-643. These alpha-blockers reduced pressor response to noradrenaline (2 microgram/kg i.v.) merely to one half at an oral dose of 100 mg/kg. 2) All these alpha-blockers did not reduce blood pressure but markedly increased heart rate in NWR. On the other hand, they reduced blood pressure of SHR without marked increase in heart rate. Although the alpha-blocking and cardiac stimulating effects of phenoxybenzamine lasted more than several days, its hypotensive effect in SHR disappeared within 24 hours. 3) An oral dose of 30 mg/kg propranolol did not reduce blood pressure in both NWR and SHR but slightly decreased heart rate. The combined treatment of these alpha-blockers with propranolol completely abolished the cardiac stimulating effect of the alpha-blockers and resulted in a definite reduction in blood pressure of NWR and potentiated the hypotensive effect of alpha-blockers in SHR.

Binding characteristics of L-triiodothyronine to isolated rat liver chromatin

The binding characteristics of [125I]-labeled L-triiodothyronine (T3) to chromatin isolated from rat liver nuclei were investigated. Binding of T3 to chromatin showed temperature-, incubation time-, and DNA concentration-dependence. According to Scatchard analysis, the apparent equilibrium dissociation constant was 225 pM, with a maximum binding capacity of about 0.2 pmoles per mg DNA. Displacement studies with unlabeled thyroxine (T4) and T3 showed that the binding sites for T4 might be the same as T3 but the binding affinity of the former was less than that of the latter. The binding was completely inhibited by the eukaryotic RNA polymerase inhibitor, rifampicin AF/021, but not by the prokaryotic inhibitor, rifampicin and alpha-amanitin. These observations indicate that the receptors for T3 have certain properties in common with RNA polymerase or other enzyme proteins which are sensitive to the rifampicin derivative. The hormone--chromatin fragments complex was solubilized from residual chromatin by digestion with DNase, but not with RNase, suggesting that the T3 receptors localize in the DNase-sensitive regions of DNA in the chromatin. This provides a useful method to use to investigate the localization of the receptor proteins in the chromatin and the interaction of the hormone-receptor complex with DNA.

False-positive liver scan caused by anomalous quadrate lobe and right portal branch

A case of early cirrhosis exhibiting a discrete scan defect along the inferomedial margin of the liver near the hilum is described. Peritoneoscopy and percutaneous transhepatic portography disclosed that the quadrate lobe had a tongue like protrusion increasing activity below the hilum on the scan and a dilated right portal branch which divided near the superior mesenteric vein entered the liver at the porta hepatis.

Anti-hypertensive action of DL-alpha-tocopharyl esters in rats

1. Oral administration of DL-alpha-tocopheryl nicotinate (EN) (0-04 or 0-2 mmol day-1 kg-1) or DL-alpha-tocopharyl acetate (EA) (0-2 mmol day-1 kh-1) delayed the progress of hypertension in unilaterally nephrectomized rats, which were treated with deoxycorticosterone and salt, and in genetically hypertensive rats (SHR) which were given sodium chloride solution. Suppression of body weight gain, incidence of pneumonia and mortality were reduced by treatment with EN or EA. 2. Severe hypertension in old SHR (9 months) further progressed, when drinking water was replaced by sodium chloride solution, and four out of ten of these animals died of cerebral haemorrhage during 4 weeks. The administration of EN or EA prevented the increase in blood pressure and incidence of stroke.

Crossed inhibition as revealed by cross-correlogram between bilateral homonymous motor unit spikes in man

Neuromuscular unit (NMU) spikes activated during the tonic vibration reflex (TVR) in man were studied by means of the cross-correlogram test. Those NMUs which preferredly fired at some definite interval with good correlation with vibration were called "locked" spikes. The amount above zero correlation level seen in the cross-correlogram was expressed as ipsilateral "excitatory frequency", Ef. TVR contraction of the ipsilateral quadriceps femoris muscle was stimulated by voluntary contraction of the contralateral quadriceps femoris. I. Cross-correlogram test of the contralateral voluntary NMU spikes with ipsilateral vibration revealed "contralateral inhibitory modulation". Such inhibitory modulation was observed in 24% of the contralateral NMUs during voluntary tracking contraction with visual feed-back and in 22% of NMUs during blind simulated contraction without visual feed-back. The "subtracted" amount, i.e., contralateral inhibitory modulation, was also expressed as the contralateral "inhibitory frequency", If, which was calculated from the indentations of the cross-correlogram. 2. When varied vibratory frequency was applied to the muscle both Ef and If attained their maximum value around an "optimal frequency" of vibration, i.e., 80-95 HZ. 3. The ratio Ef/If was proposed as the reciprocal co-activation ratio which was fairly independent of the change of vibratory frequency. An average value of Ef/If ratio was calculated at 2.2 +/- 0.9 from 19 experiments.

A combined use of triphenyl phosphite and 2,2'-dipyridyl diselenide as a coupling reagent in oligonucleotide synthesis

Oligonucleotides and nucleoside phosphoramidates can be synthesized in high yields by a combined use of triphenyl phosphite and 2,2'-dipyridyl diselenide as a coupling reagent.

Fine structure of synaptic vesicles in two types of nerve terminals in crayfish stretch receptor organs: influence of fixation methods

Crayfish stretch receptor organs were used. The standard procedure consisted of primary fixation with a 1.6% glutaraldehyde solution containing either buffer which was 60% hyposmotic or buffer which was isosmotic with the physiological solution (440 milliosmols), washing with isosmotic buffer, and postfixation with an isosmotic 1% osmium tetroxide solution. Under these conditions, we encountered two types of nerve terminals; small-vesicle terminals (SVTs) containing small elongated vesicles (300 approximately 330 A) and large-vesicle terminals (LVTs) containing larger round vesicles (430 A). Their location and physiological evidence suggest that SVTs and LVTs are inhibitory and excitatory, respectively. A hyperosmotic primary fixation solution due to increased glutaraldehyde concentration gave results similar to the standard procedures, while a hyperosmotic primary fixation solution due to increased buffer concentration caused shrinkage of the nerve terminal. A hyperosmotic buffer wash produced elongation of vesicles in SVTs and LVTs, while washing with hypoosmotic buffer rendered vesicles in both types round. Direct fixation with isosmotic osmium tetroxide yielded less elongated vesicles in SVTs and irregularly round vesicles in LVTs. However, under all conditions, vesicles in SVTs were smaller than those in LVTs. These results suggest that the consistent morphological difference in vesicles between SVTs and LVTs is size rather than shape, and it is important to standardize the osmolarity of primary fixation and washing solutions when discussing the differences of vesicle shape in various kinds of synapses.

Effects of sudden changes in external sodium concentration on twitch tension in isolated muscle fibers

When [Na] was suddenly introduced to single muscle fibers (Xenopus or frog), which had been pretreated with Na-free solution (Tris-substituted), the time-course of twitch recovery was very variable, half-time ranging from less than 1 S to 5 S. The [Na] vs. twitch height relationship was also variable. In small Xenopus fibers, decreases of [Na] to 50% increased the twitch, while in large Xenopus fibers twitch height remained constant or decreased as [Na] was decreased to 50%. The apparent diffusion constant (D') of Na+ or K+, calculated from the time-course of twitch recovery and the [Na] vs. twitch relation, and from the time-course of the slow repolarization upon sudden reduction of [K] was about 1-1.5 X 10(-6) cm2/S. This is one order of magnitude smaller than the diffusion constants in an aqueous solution. Even if the tortuosity factor of the T system is taken into account, there remains a substantial discrepancy. Although our value of D' is subject to various errors, if we accept the value, the twitch recovery is predicted to be either very quick or slow depending upon the variation of [Na]-twitch relation and fiber size. Thus, both quick and slow twitch recoveries can be explained by the diffusion time of Na+ in the T system, and therefore the results are consistent with the idea that the T system is excitable.

Effects upon spindle discharges of electrical stimulation of static fusimotor fibers with concomitant application of muscle vibration

Discharges of single afferent fibers from the primary endings of the soleus muscle spindles were recorded from thin dorsal root filaments in cats anesthetized with urethane and chloralose. The distal cut end of the ventral root was split into fine filaments to obtain functionally single fusimotor fibers. The fusimotor fibers obtained in this study were of the static type. The soleus muscle was sinusoidally stretched at 70 Hz with various amplitude concurrently with 100 Hz electric stimulation of fusimotor fiber. The spindle afferent discharges were analysed by compiling inter-spike interval histograms and cross-correlograms between the afferent spikes and the stimulus pulses applied to the fusimotor fiber. The same analysis was also made between the afferent spikes and peak extensions of muscle yielded by vibratory stimulation. One-third of the fusimotor fibers were capable of driving the spindle afferents. The driving of fusimotor stimulation was replaced by driving by muscle dibration of more than 10 mum amplitude applied concurrently with fusimotor stimulation. The remaining two-thirds of the fusimotor fibers could not drive the spindle afferents. In this case, the driving by muscle vibration was obtained when vibration of more than 5 mum amplitude was applied concurrently with fusimotor stimulation. It was suggested that fusimotor fibers which produced driving of the spindle afferents would terminate on nuclear chain fibers and those not producing driving on nuclear bag fibers, or the latter would terminate relatively distant from the primary ending as compared with the former.

Speed of repolarization and morphology of glygerol-treated frog muscle fibres

1. Single muscle fibres from frog semitendinosus were subjected to sudden changes in [K](o), while recording membrane potential.2. In agreement with Hodgkin & Horowicz (1960), a sudden increase in [K](o) in normal fibres produced a rapid depolarization (half-time 0.3 sec), whereas a sudden decrease in [K](o) produced a slower repolarization (half-time 2-3 sec).3. Fibres were subjected to ;glycerol-treatment', a procedure which was supposed to produce a functional disconnexion of the T-system from the surface. In these glycerol-treated fibres both depolarization and repolarization induced by changes of [K](o) took place rapidly.4. The results suggest that the slowness of the repolarization in normal fibres is due to a retention of K ions inside the T-tubules.5. Electron microscopical observation of single fibres or bundles of fibres, which have been soaked in a Ringer containing ferritin, revealed that normal fibres contained ferritin particles in the T-system, while glycerol-treated fibres showed no ferritin. Except for the presence of some large vacuoles and some swelling of the T-system, glycerol-treated fibres appeared morphologically normal.6. Prolonged soaking in a high potassium solution produced electrical effects suggesting that K ions can enter the tubules of treated fibres very slowly, in spite of their inaccessibility to ferritin.7. The main effect of glycerol-treatment does not seem to be a total disconnexion of the T-system from the fibre surface, but rather constriction of the T-tubules near their openings to the exterior.

Presynaptic inhibition at inhibitory nerve terminals. A new synapse in the crayfish stretch receptor

Previous physiological evidence has shown that the receptor neuron of the slowly adapting stretch receptor organ of crayfish receives synapses from three inhibitory axons, while the receptor muscle is innervated by both excitatory and inhibitory axons. Fine structural studies have indicated that after certain preparative procedures synaptic vesicles in the inhibitory terminals on dendrites of the receptor neuron appear small and elongate, while those in the excitatory terminals on the receptor muscle are round and larger. This study describes a new synapse between two inhibitory nerve endings on the receptor neuron. One axon, containing small elongate vesicles, forms a presynaptic chemical contact with another morphologically similar axon that, itself, presumably releases inhibitory transmitter onto the receptor neuron. A second type of presynaptic axo-axonic synapse, analogous to one previously described in another crustacean muscle, was also found between presumed inhibitory and excitatory nerve terminals on the receptor muscle. Thus, the stretch receptor has a relatively complex organization with a morphological basis for two types of presynaptic inhibition: one on excitatory terminals and the other on inhibitory terminals.