Experimental induction of cerebral aneurysms in monkeys

Saccular cerebral aneurysms were successfully induced in two monkeys treated with ligation of the common carotid artery, experimental hypertension, and beta-aminopropionitrile feeding. The cerebral aneurysms developed on the large arteries at the base of the brain, such as the anterior communicating artery and the internal carotid artery at the origin of the posterior communicating artery. Because of the similarity of the monkey to man as a species, the present results strongly suggest the significance of postnatal aggravating factors in the development of cerebral aneurysms in man.

Distribution of uranium in human lungs

Several human lung samples were dissected into lobes and uranium and silicon contents in each lobe were determined by the fission track method and the inductively coupled plasma-atomic emission spectrometry (ICP-AES), respectively. It was found that both uranium and silicon concentrations were high in the upper lobe compared with those in the lower one. Though the tendency may be mainly interpreted by the deposition way of airborne dust in the lung, the higher U/Si concentration ratio in the upper part than that in the lower part of lungs may suggest the partial removal of uranium deposited in the lower part of the tissue.

Duodenal neoplasms: role of CT

In a retrospective study of 14 cases of duodenal neoplasms evaluated by computed tomography (CT), there were four primary adenocarcinomas of the duodenum, one lymphoma, five metastatic carcinomas, two duodenal lipomas, one villous adenoma, and one leiomyoma. The CT findings were diagnostic in patients with duodenal lipomas. In 11 cases, a primary origin of the mass was clearly identifiable in the duodenum. Thickening of the bowel wall, tumor necrosis, ulceration, and intraluminal defects were common. The relationship of the masses to adjacent structures was clearly shown on CT scans. Extraluminal extent of the lesion was noted on CT scans in seven patients; however, at surgery only four of six were found to have extramural disease. The presence of adenopathy, liver metastases, and vascular and mesenteric invasion were also demonstrated on CT scans. Twelve patients underwent upper gastrointestinal tract series. A duodenal abnormality was seen in all 12 patients, but the extramural extent and distant metastatic involvement could not be seen on these examinations. CT scans allowed the accurate staging of eight of ten malignant lesions and thus helped in the management of duodenal tumors.

Rapid and sensitive method for measuring norepinephrine, dopamine, 5-hydroxytryptamine and their major metabolites in rat brain by high-performance liquid chromatography. Differential effect of probenecid, haloperidol and yohimbine on the concentrations of biogenic amines and metabolites in various regions of rat brain

A rapid and sensitive method has been developed for the simultaneous determination of norepinephrine, dopamine, 5-hydroxytryptamine and their respectively metabolites 3-methoxy-4-hydroxyphenylglycol, homovanillic acid, 3,4-dihydroxyphenylacetic acid, and 5-hydroxyindoleacetic acid in discrete brain regions of rats. The supernatants of tissue homogenates were injected directly into a reversed-phase liquid chromatography system, coupled with electrochemical detection. Each of these compounds gave a linear response over the range 5.5-200 ng/ml cerebellar homogenate (0.11-4.0 ng on column). Analytical recoveries of these compounds, added to the homogenate, were essentially complete when compared with standards dissolved in perchloric acid. The average between-assay coefficients of variation for all these compounds were lower than 6.9% over the range 5.5-200 ng/ml. The within-assay coefficients of variation were lower than 9.7%, measured at 5.5 or 23.6 ng/ml. With the present test parameters and mobile phase conditions, all compounds were readily oxidized at 0.8 V vs. a Ag/AgCl reference electrode. The method was applied to an analysis of the differential activity of biogenic amines in the rat striatum, hypothalamus, and hippocampus, produced by probenecid, haloperidol and yohimbine.

Tolerance to hyperthermia produced by morphine in rat

The present study addressed the prevailing notion that the rat develops tolerance only to the hypothermic effect of morphine and not to its hyperthermic effect. Rectal temperatures were measured at different intervals after various test doses of morphine in rats that had been rendered tolerant to morphine antinociception, by daily intraperitoneal injections of 0, 20, or 200 mg/kg morphine, and dependent, as seen by naloxone-produced loss of body weight. The well-known tolerance to the hypothermic effect was confirmed by changes in the dose-response curves for latency to peak hyperthermic response. In the falling arm of the test dose time/effect curve, consistent, clear decreases in morphine hyperthermia were seen. These decreases were proportional to the chronic treatment dose, and occurred in a normal test environment, where acute hypothermic effects were produced by morphine at short test intervals, and in a warm test environment, where no hypothermia was seen. Similar effects were noted when the data were analyzed in terms of area under the time/effect curve for hyperthermia. In the morphine-treated animals, decreased hyperthermia was seen despite serum morphine levels at the time of testing being up to twice as high as those in control rats. It was concluded that substantial tolerance develops to hyperthermia produced by opiates in rats. The previous difficulty in seeing this effect is discussed in regard to the probability that, in naive rats, the effect of morphine shortly after administration of a test dose reflects a summation of two opposing, acute thermic effects. The findings challenge the view that tolerance develops only to the depressant, and not to the excitatory, effects of opiates.

Intoxicating effects of lorazepam and barbital in rat lines selected for differential sensitivity to ethanol

The motor impairing effects and plasma concentrations of barbital and lorazepam were studied in the alcohol tolerant (AT) and alcohol non-tolerant (ANT) rat lines developed for low and high sensitivity to motor impairment from ethanol. The mixed (M) line, from which the AT and ANT rats were derived, was also included in the study. Like ethanol, barbital and lorazepam impaired the performance of the ANT rats more than that of the AT rats. The motor performance of the M rats was relatively more impaired after barbital than after lorazepam administration at the same dose used in the AT and ANT rats. At the two latter time points (2.5 and 3.5 h) the sensitive ANT rats had significantly higher serum barbital concentrations than the AT rats. The serum barbital concentrations of the AT and ANT rats did not differ, however, at the two first time points (0.5 and 1.5 h) of the tilting plane tests, although the ANT rats were significantly more intoxicated. The concentrations of lorazepam in plasma do not explain the differential motor impairment either, since the sensitive ANT rats had lower plasma concentrations than the insensitive AT rats. The results, thus, suggest that the selection involved in the development of the AT and ANT lines has not been specific for ethanol. The results also support the idea that ethanol, barbiturates and benzodiazepines have some modes of action in common.

Simultaneous determination of biogenic amines and morphine in discrete rat brain regions by high-performance liquid chromatography with electrochemical detection

A simple and sensitive method has been developed for the simultaneous determination of norepinephrine, epinephrine, dopamine, 5-hydroxytryptamine, 5-hydroxyindoleacetic acid, and morphine in discrete rat brain regions by reversed-phase high-performance liquid chromatography with electrochemical detection. Perchloric acid extracts of the tissue were directly injected into the chromatographic system. Each of these compounds gave a linear response over the range of 20-160 ng/ml cerebellar homogenate (0.4-3.2 ng on column). Recoveries of these compounds, added to the homogenates, were complete when compared with standards dissolved in perchloric acid. The average between-run coefficients of variation for all these compounds were lower than 7.4% over the range of 20-160 ng/ml, and the within-run coefficients of variation at 20 ng/ml were lower than 8.7%. The present method has been applied to a study of the effects of intraperitoneal administration of morphine on biogenic amines in several discrete rat brain regions.

Increased vitamin A in esophagus and other extrahepatic tissues after chronic ethanol consumption in the rat

In rats fed ethanol (36% of total energy) for 1 month, vitamin A content of the esophageal mucosa was found to be increased 5-fold, compared to animals pair-fed an isocaloric control diet containing the same amount of vitamin A. Similar results were observed with diets of either lower vitamin A content or zinc supplementation. Significant increases of retinoids were also found in lungs, trachea, kidneys, and testes, but not in the eyes. These increases in extrahepatic tissues contrasted strikingly with the concomitant decrease in the liver and suggests that chronic ethanol consumption may be associated with some mobilization of vitamin A from the liver to other organs.

Early changes of experimentally induced cerebral aneurysms in rats: scanning electron microscopic study

To obtain information about the early changes of experimentally induced cerebral aneurysms in rats, the luminal surface of branching areas of their cerebral arteries was examined with a scanning electron microscope. At the branching sites of major cerebral arteries in the control animals, the intima just distal to the apex markedly protruded into the lumen forming a linear bank-like intimal pad. Along and distal to this pad, there was a shallow long groove (juxta-apical groove). Such grooves were much deeper and wider in experimental animals than those in the control rats. By studying various stages of early aneurysmal changes, cerebral aneurysms were proven to develop from such grooves. In deep juxta-apical grooves and small aneurysms, round regenerated endothelial cells with a large number of microvilli were diffusely present. Degenerated cells with balloons and craters were observed intermingled with such regenerated cells. Interendothelial gaps were also seen. The present study showed the complex structure of the apex of arterial bifurcation in rats, including bank-like intimal pads. Such complex structures of the branching sites were considered to be responsible for the initiation of cerebral aneurysms due to endothelial injury possibly caused by turbulent flow there.

Early changes of experimentally induced cerebral aneurysms in rats. Light-microscopic study

The changes of the anterior cerebral artery/olfactory artery junction, one of the favorite sites of aneurysm formation, in rats treated with unilateral ligation of the common carotid artery and renal hypertension were investigated by light microscopy. The initial changes of aneurysm occurred not at the apex itself, but on the distal side of the major branch adjacent to the apex, at the intimal pad and the neighboring distal portion. Here the internal elastic lamina showed various degenerative changes and disappearance. The neighboring distal portion adjacent to the intimal pad showed a shallow depression associated with a thinning of the media due to a decrease of medial smooth muscle cells in number even in some control animals. Such degenerative changes of the internal elastic lamina and medial smooth muscle cells caused by hemodynamic stress due to branching structure, including intimal pads, augmented by the experimental treatment, are supposed to be the basis for aneurysm formation.

Studies on avian erythrocyte metabolism. XIV. Effect of CO2 and pH on P50 in the chicken

The O2 affinity (P50) of erythrocyte suspensions from 18-day chick embryos, from 2-, 5-, 8-, and 14-day chicks, and from mature chickens decreased with increasing concentrations of either CO2 or H+, particularly at a pH near 7.4 and at 37 degrees C. A greater effect on delta P50's was observed from increasing H+ concentration from pH 8.0 to 6.8 in cell suspensions from 18-day embryos (28.8 Torr at 0% CO2) and adult chickens (55.1 Torr at 0% CO2) than from increases in CO2 concentration at any given pH. The Bohr effect (delta log P50/delta pH) in the absence of CO2 was -0.508 and -0.479 for cell suspensions from 18-day chick embryos and adult birds, respectively. The specific effect of CO2 on the Bohr effect, regardless of the CO2 concentration, indicates that the delta P50/0.1 pH is approximately 1.35 and 2.45 Torr for the embryo and adult chicken blood. These results indicate that increasing H+ and CO2 concentrations markedly affect the P50 of chicken blood and that even subtle changes in either could play a significant role physiologically in regulating blood P50 in birds.

Differential sensitivity to ethanol, pentobarbital, and barbital in spontaneously hypertensive and normotensive Wistar-Kyoto rats

Ethanol, pentobarbital, and barbital sleep times and blood levels on awakening were determined in female spontaneously hypertensive (SH) and normotensive Wistar-Kyoto (WK) rats. Ethanol-induced sleep times were significantly longer for SH than for WK and blood ethanol concentrations on awakening were significantly lower in SH than in WK rats. By contrast, pentobarbital and barbital sleep times for SH rats were significantly less than for WK rats and barbiturate blood levels at awakening were significantly higher in SH than in WK rats. No differences were observed between SH and WK rats with respect to the disappearance of ethanol, pentobarbital, and barbital from blood and in the apparent volume of distribution of these drugs. These observations suggest differential CNS sensitivity of the SH and WK rats to ethanol and barbiturates and provide additional support for the notion that there exist differences in the modes of acute action of these drugs.

Familial osteodysplasia associated with trigeminal neuralgia: case report

A 24-year-old woman suffering from left trigeminal neuralgia presented with the familial occurrence of skeletal anomalies simulating Hajdu-Cheney syndrome. She was of a short stature and had low-set ears, protrusion of the bilateral temporal and occipital bones, platybasia, basilar impression, and dental anomaly. Vertebral angiography disclosed marked displacement to the left and dorsally of the basilar artery, which was confirmed during the operation to have compressed the left trigeminal nerve in the cerebellopontine angle narrowed by the unusually protruded bony structure. Cases of Hajdu-Cheney syndrome have occasionally been reported, a few combined with facial spasm, but Hajdu-Cheney syndrome with trigeminal neuralgia is very rare. The patient's family members were surveyed. The possible cause of the neuralgia with its relation to the osteodysplasia is briefly discussed.

Rapid and sensitive analysis of morphine in serum by reversed-phase high performance liquid chromatography with electrochemical detection

A method is described for the determination of morphine in serum. Separation and quantitation are performed by reversed-phase high performance liquid chromatography with electrochemical detection. A sample size of 100 microL or less is required for detection of concentrations as low as 1 to 2 ng/mL. In trials with standard solutions, recovery was 75%. The between-run and within-run coefficients of variation were 7.3% (over the range of 5 to 200 ng/mL) and 9.1% (at 5 ng/mL), respectively.

Determination of picogram levels of brain catecholamines and indoles by a simplified liquid chromatographic electrochemical detection method

A simple and rapid method for the simultaneous determination of norepinephrine, epinephrine, dopamine, 5-hydroxytryptamine and 5-hydroxyindoleacetic acid in rat brain regions by high-performance liquid chromatography (HPLC) with electrochemical detection has been developed. Perchloric acid extracts of the tissue were directly analyzed in the HPLC system. Each of these compounds gave a linear response over the range of 10-320 ng/ml cerebellar homogenate (0.2-6.4 ng on column). Analytical recoveries of these compounds added to the homogenates were complete when compared with standards dissolved in perchloric acid. The average between-run coefficients of variation for all these compounds were lower than 6.7%, over the range of 10-320 ng/ml, whereas the within-run coefficients of variation at 10 ng/ml were lower than 6.9%. Under the present instrumental and mobile phase conditions, all compounds were readily oxidized at 0.72 V vs. a Ag/AgCl reference electrode. The present method has been applied to a study determining the basal levels of these compounds in several rat brain regions as well as levels after medium raphe lesions.

Isolation of a tetracycline-resistance plasmid excised from a chromosomal DNA sequence in Bacillus subtilis

When Bacillus subtilis GSY908 (recE4-) (H. C. Spatz and T. A. Trautner, 1971, Mol. Gen. Genet. 113, 174-190) protoplasts were infected with Staphylococcus aureus plasmid pNS1 specifying tetracycline resistance (Tcr) (N. Noguchi et al., 1983, Gene 21, 105-112), which was modified such that it either could not replicate or did not carry a functional Tcr gene, a plasmid with a molecular weight of 3.1 X 10(6) (4.9 kb) was generated in Tcr phenotypes. This plasmid, named Tcr pNS1981, exhibited completely different restriction endonuclease cleavage patterns to pNS1 and showed only negligible sequence homology in hybridization experiments. Southern hybridization experiments revealed that pNS1981 arises by excision of a B. subtilis chromosomal DNA sequence. No sequence corresponding to pNS1 was detectable on the chromosome of pNS1981-maintaining B. subtilis. The production of pNS1981 was also observed in B. subtilis RM125 (r-Mm-Mrec+) (T. Uozumi et al., 1977, Mol. Gen. Genet. 152, 65-69.) with almost the same frequency as B. subtilis GSY908. Since the recipient B. subtilis Marburg 168 derivatives stated above are sensitive to Tc, the results indicate that information essential for Tcr is under negative regulatory control in the integrated state on the chromosome. Restriction endonuclease analysis suggested that pNS1981 is essentially the same as pBC16, formerly found in B. cereus (K. Bernhard, H. Schrempf, and W. Goebel, 1978, J. Bacteriol. 133, 897-903).

Roughness-Induced Dynamic Loading at Dry and Boundary-Lubricated Sliding Contacts

Measurements of instantaneous normal and frictional forces have been made at smoothly sliding hemispherical steel contacts under nominally dry and boundary-lubricated conditions. Normalized contact force fluctuations generated by surface irregularities are presented. Instantaneous frictional relations are characterized by performing spectral and transfer function computations on the measured signals. The qualitative dynamic frictional behavior is shown to be similar at dry and boundary-lubricated contacts. However, the magnitude of the dynamic loading is considerably reduced in the presence of lubrication. In both cases, an apparent time-varying frictional behavior is found to exist.

Studies on avian erythrocyte metabolism. XIII. Changing organic phosphate composition in age-dependent density populations of chicken erythrocytes

These studies were performed to determine whether the erythrocytes (RBC's) of chickens are able to alter the concentrations of organic phosphates, particularly inositol pentakis (dihydrogen phosphate) (inositol-P5), in response to anemia. Acute anemia with 33.5% reticulocytes (retics) in the peripheral blood of 4-month-old White Leghorn cockerels was produced after two successive days of controlled bleeding. Five populations of RBC's were prepared from blood of these anemic birds based upon age-dependent density by angle rotor centrifugation. The relative increase in age of Fraction 1 (younger cells) through Fraction 5 (oldest cells) was verified by increased hemoglobin concentration and decreased retic count and cell volume. The acid aqueous-soluble phosphates from each RBC fraction were extracted, fractionated by ion exchange column chromatography, and the concentration of inorganic phosphate (Pi), adenosine triphosphate (ATP), and inositol-P5 quantitated by wet-ash phosphate analysis. Determination of Pi, ATP, and inositol-P5 in Fraction 1 (younger cells, 7.4% retics) from the initial (Day 1) blood withdrawn gave 4.3, 5.7, and 18.6 mumoles Pi/ml RBC, respectively. On Day 4 of controlled-bleeding, Pi, ATP, and inositol-P5 concentrations in Fraction 1 (95.1% retics) were 12.7, 10.6, and 12.3 mumoles Pi/ml RBC, respectively. On Day 11, after 1 week recovery from controlled-bleeding, the values for Pi, ATP, and inositol-P5 in Fraction 1 (37.7% retics) were 5.0, 5.4, and 19.0 mumoles Pi/ml RBC, respectively, which were similar to the values before bleeding.(ABSTRACT TRUNCATED AT 250 WORDS)

Interactions Between Dynamic Normal and Frictional Forces During Unlubricated Sliding

The results of measurements showing large normal and frictional force oscillations during unlubricated smooth sliding between steel surfaces are presented. The measurements were made on a pin-on-disk type apparatus instrumented with piezoelectric force and acceleration transducers. Spectral analysis of the contact forces (including inertia forces) up to frequencies of 2 kHz indicate that the fluctuations have their major components in this frequency range. The force oscillations are primarily associated with normal and tangential contact vibrations which are excited by surface irregularities being swept through the contact region during sliding. Transfer function analyses between the normal and frictional forces show the frictional force fluctuations to be in phase with the normal force fluctuations, but related in magnitude by a ratio larger than the concurrently-measured (average) kinetic friction coefficient. This larger oscillatory (or AC) friction coefficient is indicative of fluctuations in the instantaneous coefficient of friction which are shown to occur in synchronism with the contact force oscillations.