Systemic lipopolysaccharide and pokeweed mitogen increase quinolinic acid content of mouse cerebral cortex

The effects of lipopolysaccharide and pokeweed mitogen on brain L-tryptophan and quinolinic acid (QUIN) concentrations were investigated in C57BL/6NCR mice. Twenty-four hours after an intraperitoneal injection of lipopolysaccharide (5 micrograms from Salmonella abortus equii) or pokeweed mitogen (500 micrograms), cortical QUIN concentrations were increased by 81 +/- 6% and 182 +/- 15%, respectively. Plasma QUIN was increased 175 +/- 7% of control in pokeweed-mitogen treated mice only. Brain L-tryptophan concentrations were increased, whereas plasma L-tryptophan concentrations were decreased. The consequences of increased QUIN concentrations during endotoxin and mitogen exposure remain to be determined.

Endothelium-dependent relaxation to aggregating platelets in isolated basilar arteries of control and hypercholesterolemic pigs

The role of the endothelium was examined in the response to aggregating platelets in cerebral arteries from normal and hypercholesterolemic animals. Male Yorkshire pigs were fed either a normal diet or a 2% high-cholesterol diet for 10 weeks. Endothelium-dependent responses were examined in vitro. In rings of basilar arteries from control animals aggregating platelets caused endothelium-dependent relaxations, which were significantly inhibited by apyrase, an adenosine diphosphatase and triphosphatase, but were augmented by methiothepin, a combined S1- and S2-serotonergic blocker. In quiescent rings platelets induced contractions that were inhibited by the presence of the endothelium; these contractions were significantly inhibited by methiothepin, but not by ketanserin (an S2-serotonergic blocker) or dazoxiben (a thromboxane-synthetase blocker) in the presence or absence of SQ29548 (a thromboxane-receptor blocker). Adenosine diphosphate but not serotonin caused endothelium-dependent relaxations. In cholesterol-fed animals the endothelium-dependent relaxations in response to aggregating platelets and adenosine diphosphate were impaired. These experiments indicate that 1) the endothelium inhibits the vasoconstrictor effect of aggregating platelets in porcine cerebral arteries; 2) platelet-induced relaxations are achieved mainly by a purinergic mechanism, while platelet-induced contractions are mediated by activation of S1-serotonergic receptors with little contribution of thromboxanes; and 3) hypercholesterolemia impairs the endothelium-dependent relaxations in response to aggregating platelets due to the impaired responses to adenosine diphosphate.

Alterations in endothelium-dependent responsiveness of the canine basilar artery subarachnoid hemorrhage

To investigate the alteration of endothelium-dependent responses in chronic vasospasm after subarachnoid hemorrhage (SAH), experiments were carried out in the double-hemorrhage canine model. After the presence of vasospasm was confirmed by cerebral angiography on Days 0 and 7, pharmacological studies on the basilar artery were conducted in vitro on Day 8. In the SAH group, endothelium-dependent relaxation was abolished in response to arginine vasopressin and was significantly reduced in response to thrombin. Endothelium-independent relaxation in the SAH group was preserved in response to papaverine and was minimally reduced in response to sodium nitroprusside. Endothelium-dependent contraction in response to arachidonic acid, acetylcholine, the calcium ionophore A23187, adenosine diphosphate, mechanical stretching, and hypoxia persisted in the SAH group. The maximal contraction to KCl and uridine triphosphate, which is endothelium-independent, was diminished in the SAH group, but not changes in sensitivity were noted in the concentration-response relationships. A significant correlation was observed between the degree of vasospasm determined angiographically and the loss of endothelium-dependent relaxation. The loss of endothelium-dependent relaxation and the persistence of endothelium-dependent contraction suggest that the deterioration in the endothelium-dependent responses may be an important component in the pathogenesis of cerebral vasospasm.

Determination of the levels of urokinase and its receptor in human colon carcinoma cell lines

At present, there is a lack of availability of differentiation markers for colon carcinoma. This may, in part, be a consequence of the diversified function of the normal human colon. This study addresses the possibility that the expression of urokinase and its receptor is inversely related to differentiation in colon carcinoma. Six colon carcinoma cell lines including three well-differentiated (CBS, GEO, FET) and three poorly differentiated ones (HCT116, HCT116b, RKO) were screened for urokinase receptor display and secretion of the plasminogen activator. A radioreceptor assay was used to determine receptor levels. Binding of radioactive urokinase to colon cells was saturable, specific, and time dependent. Cell-bound 125I-labeled protease was unaffected by the presence of epidermal growth factor, low-molecular-weight urokinase, plasminogen, or transferrin. Time course studies revealed that maximum amounts of radioactive tracer were bound in a 30-min period with no change occurring over the course of a 90-min incubation. Scatchard analysis of ligand binding indicated that the well-and poorly differentiated cells could be separated on the basis of receptor display; the aggressive RKO, HCT116, and HCT116b expressed in excess of 10(5) sites per cell, while the more indolent CBS, GEO, and FET possessed less than 1.5 X 10(4) receptors per cell. The colon carcinoma cells were also analyzed for urokinase in the conditioned medium. Low levels of the plasminogen activator (0.8 to 1.3 ng/ml/10(6) cells/72 h) were associated with the more "mature" cells. This was in contrast to the elevated levels of the protease (3.9 to 11.4 ng/ml/10(6) cells/72 h) present in the medium derived from the more aggressive cells (HCT 116, HCT116b, RKO). Thus, secreted urokinase and/or the expression of cellular receptor for the plasminogen activator may provide useful measurements of the degree of undifferentiation of in vitro colon carcinoma.

Production of uric acid in cerebrospinal fluid after subarachnoid hemorrhage in dogs: investigation of the possible role of xanthine oxidase in chronic vasospasm

Based on accumulating evidence of the role of xanthine oxidase (XO) in generating oxygen free radicals and causing tissue damage during ischemia, we examined the possible role of XO in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH). After inducing SAH in dogs by two autologous blood injections 2 days apart, chronic vasospasm of the basilar artery was reliably produced. There was a 3.5-fold elevation in uric acid (UA), the product of XO, in the cerebrospinal fluid (CSF) of these animals. Parenteral administration of allopurinol (i.v., 25 mg/kg, every 6 hours), a specific blocker of XO, successfully abolished the elevation in CSF uric acid levels due to SAH. However, angiographic vasospasm measured on Day 7, morphological changes observed by electron microscope, and elevated CSF prostaglandin levels were not altered by the treatment. It can be concluded that the observed activation of the enzyme XO, which is a well-known source of oxygen free radicals in ischemia in various organs, is not playing a major role in the pathogenesis of chronic cerebral vasospasm in this animal.

Cerebrospinal fluid levels of uric acid in dogs and the effect of allopurinol

Uric acid (UA) levels in cerebrospinal fluid (CSF) were measured in 15 dogs and the entrance and effect of allopurinol, a specific inhibitor of enzyme xanthine oxidase (XO), in brain were measured by sampling CSF in dogs. Allopurinol was administered intravenously 25 mg/kg every 6 h for 48 h. Drug level as well as UA level in plasma and CSF was measured by high-performance liquid chromatography. A significant concentration of allopurinol was achieved in CSF and a remarkable suppression of CSF UA level was observed at all time points measured. Decrease of UA in CSF level was more pronounced than in plasma, and was not considered secondary to suppression of systemic XO activity. Therefore the regimen employed was proven to be sufficient to suppress XO activity in the subarachnoid space, and drug concentration observed in CSF during this period (5 micrograms/ml) is considered to be in the therapeutic range.

Hemiparesis caused by vertebral artery compression of the medulla oblongata. Case report

The case is reported of a patient with progressive left hemiparesis due to vascular compression of the medulla oblongata. Metrizamide computerized tomography cisternography revealed that the left vertebral artery was compressing and distorting the left lateral surface of the medulla. Compression was surgically relieved and symptoms improved postoperatively. Neurological and symptomatic considerations are discussed in relation to the topographical anatomy of the lateral corticospinal tract.

Intratesticular steroid levels and their hormonal control

Litter-mate adult male rats were treated with daily intramuscular injections of ACTH (10.5 micrograms), dexamethasone (2.0 mg), ethynyl estradiol (1.7 micrograms) and hCG (5 IU) for three consecutive days. The animals were sacrificed on the fourth day and the intratesticular and peripheral plasma steroid levels were analyzed. The steroids measured by radioimmunoassay included pregnenolone, 17-hydroxypregnenolone, dehydroepiandrosterone, progesterone, 17-hydroxyprogesterone, androstenedione, testosterone and dihydrotestosterone. In addition, the sulphoconjugated forms of pregnenolone, dehydroepiandrosterone, testosterone and dihydrotestosterone were estimated in the peripheral blood. The administration of ACTH diminished the intratesticular levels of all steroids studied. Also dexamethasone and ethynyl estradiol treatment suppressed all intratesticular steroid levels, except that of pregnenolone (the former) and of 17-hydroxyprogesterone (the latter). The suppressive effect of ethynyl estradiol was strongest on the levels of the delta 5-steroids and that of dexamethasone on the delta 4-steroids; the latter was significantly stronger than the effect of ACTH. The stimulatory effect of hCG was limited to the metabolism of progesterone and was restricted to the sequence: 17-hydroxyprogesterone----androstenedione----testosterone---- dihydrotestosterone. Dexamethasone-suppression, and hCG-stimulation of the intratesticular levels of delta 4-steroids, was mirrored by corresponding changes in the peripheral plasma levels, with the exception of the plasma levels of androstenedione which were not influenced by any of the treatments studied. Also the suppression of intratesticular testosterone and dihydrotestosterone levels by ACTH, dexamethasone, or ethynyl estradiol was closely reflected by their plasma levels both in the unconjugated and sulphoconjugated forms. On the hand, the administration of ACTH diminished the intratesticular levels of pregnenolone and progesterone but significantly increased those in the plasma. Moreover, both ACTH and ethynyl estradiol reduced the levels of all delta 5-steroids in testicular tissue, but not in the peripheral plasma, although they decreased the circulating levels of pregnenolone sulphate and dehydroepiandrosterone sulphate. The data are interpreted as suggesting that the hormonal agents studied interfere with testicular steroidogenesis through different mechanisms.

Observations on synkinesis in patients with hemifacial spasm. Effect of microvascular decompression and etiological considerations

In 95 patients with hemifacial spasm, synkinetic actions were measured objectively using electromyographic examination of the blink reflex and impedance audiometry. Abnormal synkinesis between the orbicularis oculi and the orbicularis oris muscles was recorded in 93% of cases, while synkinesis between the stapedius muscle and the facial muscles was recorded in 87%. Neither of these effects could be demonstrated on the unaffected side. The examinations were performed before and after microvascular decompression in 66 cases. Rapid disappearance of synkinesis, often within 10 days, was observed after the relief of vascular compression in 81% of patients who had not undergone previous peripheral facial nerve block procedures. These findings indicate that the synkinesis seen in hemifacial spasm is essentially a reversible condition, and suggest that axonal ephaptic conduction at the vascular compression site plays an important role in the pathophysiological mechanism of hemifacial spasm.

Electrophysiological characteristics of renorenal reflexes in the cat

1. Experiments were done in anaesthetized, paralysed and artificially ventilated cats to determine the fibre composition of renal nerves and to study the functional characteristics of reflex responses recorded in efferent renal nerves during electrical stimulation of contralateral and ipsilateral afferent renal nerves. 2. Renal nerves were found to contain three afferent fibre groups (Abeta, Adelta and C); the majority of these fibres reach the sympathetic chain through the least splanchnic nerve. Efferent sympathetic nerves to the kidney were found to originate from the greater, lesser and least splanchnic nerves through a synapse in the coeliac ganglion. 3. Two contralateral renorenal reflex responses were demonstrated during selective stimulation of renal afferent A and C fibres. The first (A renorenal reflex) was elicited by stimulation with trains of pulses at low voltage and high frequency (200 Hz), had an onset latency of approximately 100 msec and was followed by post-excitatory depression. The second (C renorenal reflex) was demonstrated by trains of pulses at high voltage and low frequency (20--30 Hz), had an onset latency of approximately 350 msec and was also followed by post-excitatory depression. 4. Ipsilateral renorenal reflexes with characteristics similar to the contralateral reflexes were also demonstrated. 5. Renorenal reflexes were abolished by destruction of the spinal cord and administration of nicotine sulphate (5--20 mg/kg, i.v.), but were not affected by bicuculline (0.4 mg/kg, i.f.). 6. The significance and the physiological role of these renorenal reflexes as well as their pathways within the central nervous system remain to be determined.

Health care for elderly Americans: evaluation of an adult day health care model

This study was designed to analyze the cost and effectiveness of a day care program for the elderly. An experimental group of adult day care participants was compared with a control group of elderly people living in the community. The two groups were evaluated in terms of levels of physical and emotional functioning, behavioral independence in activities of daily living, institutionalization, interpersonal relationships, and re-establishment of life styles. Statistical tests of difference were used to determine if the two groups had improved or were maintained over the six-month study period (November 1973 to March 1974). The experimental group showed improvement and differed significantly from the control group in the areas of emotional functioning, self-maintenance, and interpersonal relationships. No significant differences were found in satisfaction with life styles for either group. The experimental group was somewhat, but not significantly, deficient in independence in daily living activities. Composite analysis of six combined scales indicated that the experimental group inproved in level of functioning over the study period while the control group regressed. Cost analysis of the Lexington Center indicates that adult day care services cost +12.99 per participant per day.