Analysis of renal immune-deposits in canine leishmaniasis. Preliminary results

Previous studies carried out on 34 dogs spontaneously infected by Leishmania infantum showed the presence of kidney lesions characterized by immunologically mediated glomerular and tubular damage. Glomerular immune-deposits were studied in 13 of these dogs. Immunoglobulins were isolated from kidney tissues by acid elution; IgG fractions from eluates, obtained by ammonium sulfate precipitation, were subjected to clonotypic analysis by autoradiography after isoelectrofocusing (IEF) using 125I radiolabelled goat IgG fraction-anti Fab2 of dog IgG. Idiotypic characterization of IgG eluted from kidney tissues was performed by IEF and autoradiography using both 125I radiolabelled membrane antigens of L. infantum extracted by Triton x 100 and 125I radiolabelled dog IgG for rheumatoid or anti-idiotypic activity. The IgG deposited in the kidney tissues of examined dogs were polyclonal and a specific activity against Leishmania membrane antigens was revealed. Meanwhile an anti-IgG activity of deposited immunoglobulins was not observed.

[The pharmacologic action of extracts of Polygonum punctatum Elliot (= P. acre HBK)]

In vivo pharmacological studies were carried out with the aqueous and hydroalcoholic extracts of P. punctatum Elliot. Previously we have made a phytochemical screening and a essay of acute toxicity. The extracts exhibited an inhibition of the carrageenan-induced rat paw oedema, at doses of 300 and 600 mg.kg-1 p.o. and the hydroalcoholic extract at a dose range of 100-600 mg.kg-1 p.o. reduced significantly the increase of the vascular permeability induced by histamine. The extracts showed antipyretic activity only by i.p. administration. The gastrointestinal propulsion of a charcoal suspension was affected by both extracts, but significantly only by the aqueous extract. They elicited bradycardia and lowered the arterial blood pressure, but they do not demonstrate analgesic and diuretic activities. The pharmacological effects assayed are discussed in relation to the chemical composition of this plant and also to its popular use.

Ultrasonographic measurement of the common carotid artery wall thickness in hypercholesterolemic patients. A new model for the quantitation and follow-up of preclinical atherosclerosis in living human subjects

Ultrasound high resolution B-mode imaging of human arteries allows in vivo an accurate and non-invasive determination of the thickness of the intimal-medial complex. A computer assisted procedure to measure this parameter at the level of common carotid arteries was developed. The average difference between duplicate thickness determinations was 4.6%. The thickness of the intimal medial complex of common carotid arteries was then measured in a group of hypercholesterolemic patients. This parameter was significantly greater in these patients as compared to controls (P less than 0.001). The prevalence of small plaques in the carotid arterial tree was also significantly increased in patients. Analysis of data showed that in controls, but not in patients, the thickness of the intimal medial complex increases with age (r = 0.46, P less than 0.05). Within the hypercholesterolemic group, intimal-medial complex values were greater in male patients and in smokers. It is concluded that the common carotid arteries of hypercholesterolemic patients show thickening of the intimal-medial complex. Cigarette smoking, male sex and age increase the extent of this modification. The determination of this parameter using a non-invasive technique may represent an important tool to monitor in vivo the progression and/or the regression of early atherosclerosis in man.

Neurotoxic effect of 1-methyl-4-phenylpyridinium ion on dopaminergic neurons of the retina of goldfish

Dopaminergic neurons of the goldfish retina were selectively destroyed after a single intravitreal injection of 1-methyl-4-phenylpyridinium ion (MPP+). The ultrastructural analysis of the retina 3 days after toxin administration shows darkening of some retinal neurons present in the inner nuclear layer including their cytoplasmic processes. Both uptake and release of dopamine were reduced in the toxin-injected retina, whereas choline acetyltransferase (ChAT) and glutamic acid decarboxylase (GAD) activities, as well as the uptake of D-[3H]aspartate were not affected.

Prevalence, ultrastructure of the cyst wall and infectivity for the dog and cat of Sarcocystis sp. from fallow deer (Cervus dama)

The prevalence of Sarcocystis sp. (Protozoa: Sarcocystidae) in fallow deer (Cervus dama) in Tuscany, Italy was determined by digestion technique and histological examination. Forty-four of 45 fallow deer were infected. Infections occurred in adult deer and in fawns. Samples from the heart were more intensively parasitized than samples from tongue, oesophagus and diaphragm muscle. With transmission electron microscopy, the primary cyst wall was folded and formed narrow, overlapping, sinuous projections which were often parallel to the cyst surface. Dogs fed heart samples from infected fallow deer shed sporocysts after 10-11 days. Cats fed the same samples did not shed any sporocysts.

Regression of the atherosclerotic lesion in man: the impact of noninvasive techniques

Experimental studies demonstrate that atherosclerotic plaques induced in animals can regress following appropriate treatment, but evidence in favour of the regression of atherosclerotic lesions in man is still scanty. New imaging techniques, such as high resolution B-mode echotomography, allow the visualization and measurement of anatomical parameters of the arterial wall in sample arteries of human patients "in vivo", introducing the possibility of a much more precise monitoring of early atherosclerotic lesions. New information on the natural history of atherosclerotic disease in man, including the possibility of differentiating between lesions of different clinical significance, can be expected from the wide application of these techniques to atherosclerosis research. A more precise testing of diets, drugs and physical procedures intended to obtain the regression of atherosclerosis in human beings will also be possible.

Effects of d,l-propranolol on apomorphine induced stereotyped behavior in rats

The effects of d,l propranolol on stereotyped behavior induced by apomorphine administration was studied quantitatively. d,l Propranolol caused a 2.5 leftward displacement of the control dose-response curve constructed to apomorphine-induced stereotypy; the ED50 for apomorphine was reduced from 1.87 +/- 0.38 to 0.74 +/- 0.17. The potentiation was dependent on both d,l-propranolol and apomorphine doses. Results are discussed in the light of a possible interference of the central noradrenergic systems with the expression of dopaminergic-induced stereotyped behavior.

Intimal plus medial thickness of the arterial wall: a direct measurement with ultrasound imaging

A study in vitro of specimens of human aortic and common carotid arteries was carried out to determine the feasibility of direct measurement (i.e., not from residual lumen) of arterial wall thickness with B mode real-time imaging. Measurements in vivo by the same technique were also obtained from common carotid arteries of 10 young normal male subjects. Aortic samples were classified as class A (relatively normal) or class B (with one or more atherosclerotic plaques). In all class A and 85% of class B arterial samples a characteristic B mode image composed of two parallel echogenic lines separated by a hypoechoic space was found. The distance between the two lines (B mode image of intimal + medial thickness) was measured and correlated with the thickness of different combinations of tunicae evaluated by gross and microscopic examination. On the basis of these findings and the results of dissection experiments on the intima and adventitia we concluded that results of B mode imaging of intimal + medial thickness did not differ significantly from the intimal + medial thickness measured on pathologic examination. With respect to the accuracy of measurements obtained by B mode imaging as compared with pathologic findings, we found an error of less than 20% for measurements in 77% of normal and pathologic aortic walls. In addition, no significant difference was found between B mode-determined intimal + medial thickness in the common carotid arteries evaluated in vitro and that determined by this method in vivo in young subjects, indicating that B mode imaging represents a useful approach for the measurement of intimal + medial thickness of human arteries in vivo.

Indenolol kinetics versus pharmacodynamics in hypertension

A kinetic model has been employed to compare the duration of the antihypertensive activity of indenolol to its plasma half-life both after single administration and at steady-state. After a 14 day run-in period with placebo, 60 or 120 mg indenolol were given to hypertensive patients I or II grade, according to W.H.O. guidelines, once a day for 14 days. Blood samples were drawn and blood pressure recorded at intervals after the first dose, during treatment and after the last dose of the compound. Both plasma concentration and mean arterial pressure difference curves were fitted by a first order input-output model, where plasma half-life was 4 h, while pharmacological half-life was 24 h for both dose-levels tested. Therefore, with once-a-day dose regimen an accumulation of the antihypertensive effect of indenolol was demonstrated, with 99% steady-state of blood pressure reached after 7 days, while the drug did not accumulate in the central compartment.

Ultrastructural and neurochemical effects of the presumed cholinergic toxin AF64A in the rat interpeduncular nucleus

We have studied the effect of the presumptive cholinergic neurotoxin, ethylcholine mustard aziridinium ion (compound AF64A), on ultrastructure and neurochemical markers in the rat interpeduncular nucleus (IPN). Stereotaxic injections of 1 nmol of AF64A resulted in extensive degeneration of synaptic terminals within 40 h. Ultrastructural damage to neuronal cell bodies, dendrites and axons was also sometimes observed at this stage. Five days after the injection, more severe degenerative changes were observed in a larger number of neuronal cell bodies, axons and dendrites. High affinity uptake of [3H]choline, but not [3H]GABA, was significantly decreased 24 h after toxin injection. Five days after the injection, not only choline acetyltransferase but also glutamate decarboxylase levels were significantly decreased. Our results suggest that, in addition to presynaptic cholinergic neurotoxicity, AF64A also leads to degenerative alterations of non-cholinergic neurons. Our electron microscopic observations constitute the first ultrastructural report on neuropathological damage caused by AF64A.

Cholinergic, GABAergic and excitatory amino acidic neurotransmission in the goldfish vagal lobe

Some neurotransmitter systems operating in the goldfish vagal lobe, an hypertrophied gustatory center, have been studied by means of experimental (kainic acid injection and vagal rhizotomy), neurochemical and ultrastructural methods. The use of the neurotoxin, kainic acid, revealed the existence of cholinergic and GABAergic neurons in the vagal lobe. The results of histochemical observations and biochemical assays performed after rhizotomy of sensory and motor vagal roots, suggest that the motor neurons of the vagal motor layer are cholinergic. The same experiments also indicate that the primary gustatory afferents distributing to the sensory layer of the vagal lobe are, at least in part, cholinergic. By contrast, no decrease of excitatory amino acid uptake was demonstrated following the experimental lesions. GABA is likely to play an important role in the goldfish vagal lobe, particularly in the sensory layer, where the highest level of its synthetic enzyme, glutamate decarboxylase, is recorded. The significant decrease of glutamate decarboxylase in the sensory layer after vagal rhizotomy suggests that either GABAergic primary afferents reach the vagal lobe, or that deafferentation results in a decreased GABA synthesis in intrinsic GABAergic neurons.

Increase of serum lipid-associated sialic acid concentration in dogs with neoplasms

Serum concentrations of lipid-associated sialic acid (LASA) were determined in sera obtained from 26 apparently healthy dogs (group 1), 56 dogs with nonneoplastic disorders (group 2), and 100 dogs with neoplasms (benign [group 3], malignant [group 4]), using a simple, reliable, rapid spectrophotometric procedure. The LASA concentrations were significantly increased (P less than 0.01) in group 4 dogs (malignant neoplasms) when compared with those in dogs from groups 1, 2, and 3. The sensitivity of the test was between 71.5% and 100%, and specificity was 92.3% for group 1, 67.8% for group 2, and 80.6% for group 3. A preliminary study concerning variations of serum LASA values as a marker after surgical treatment of tumor showed a good correlation between effectiveness of therapy and serum LASA concentrations.

Colonisation of Haemophilus influenzae and Streptococcus pneumoniae in the upper respiratory tract of neonates in Papua New Guinea: primary acquisition, duration of carriage, and relationship to carriage in mothers

In order to determine the age of acquisition and duration of carriage of the first strains of Haemophilus influenzae and Streptococcus pneumoniae in the upper respiratory tract of Papua New Guinea children, 25 babies were recruited at, or shortly after birth. Nasal secretions from mothers and children were cultured at 1- to 2-weekly intervals. H. influenzae and S. pneumoniae were acquired within the neonatal period by 60% of the infants, and all were colonised by both organisms within the first 3 months of life. Carriage periods for H. influenzae ranged from 6 to 221 days (mean, 74 days), and for S. pneumoniae from 5 to 290 days (mean, 96 days). Penicillin resistance was detected in 36% of the first acquired strains of pneumococci. Mothers, generally either did not carry H. influenzae or S. pneumoniae, or harboured types different to those first acquired by their infants. However, one-third of mothers subsequently became colonised with H. influenzae and S. pneumoniae types similar to those carried by their babies.

[3H] kainic acid binding sites in the synaptosomal-mitochondrial (P2) fraction from goldfish brain

Binding of [3H]kainic acid to the synaptosomal-mitochondrial fraction (P2) of the goldfish brain was studied. Specific binding to this fraction represents about half of the total binding capability of the homogenate particulate material and is enriched in synaptic membranes; it is greater by about two orders of magnitude than those given for rat brain and pigeon optic tectum membranes. Association of the ligand-site complex has a time constant lower than 1 min and the same is true for the main component of the dissociation process. The binding equilibrium is apparently not affected by substances contained in the fraction material. The analysis of the dose-response data showed a main receptor population (B max = 139 pmol/mg protein) which displayed positive cooperativity (nH = 1.29). The same behaviour was shown by washed membranes from the same fraction but, in this case, the affinity for the ligand was lower (apparent affinity constants: K'D = 0.28 nM for the intact fraction and K'D = 0.38 nM for membranes). A smaller population of sites with higher affinity was also detected both in the intact fraction and in membranes. Among the substances tested as displacers of kainic acid from the synaptosomal sites, the most effective were quisqualate and L-glutamate. Folic acid and its dihydro and tetrahydro derivatives were half as potent as glutamate whereas methyltetrahydrofolic acid and folinic acid had a very weak action. The difference between these sites and those detected on rat brain membrane preparations is discussed.

Kainic acid differentially affects the synaptosomal release of endogenous and exogenous amino acidic neurotransmitters

Presynaptic actions of kainic acid have been tested on uptake and release mechanisms in synaptosome-enriched preparations from rat hippocampus and goldfish brain. Kainic acid increased in a Ca2+-dependent way the basal release of endogenous glutamate and aspartate from both synaptosomal preparations, with the maximum effect (40-80%) being reached at the highest concentration tested (1 mM). In addition, kainic acid potentiated, in an additive or synergic way, the release of excitatory amino acids stimulated by high K+ concentrations. Kainic acid at 1 mM showed a completely opposite effect on the release of exogenously accumulated D-[3H]aspartate. The drug, in fact, caused a marked inhibition of both the basal and the high K+-stimulated release. Kainic acid at 0.1 mM had no clear-cut effect, whereas at 0.01 mM it caused a small stimulation of the basal release. The present results suggest that kainic acid differentially affects two neurotransmitter pools that are not readily miscible in the synaptic terminals. The release from an endogenous, possibly vesiculate, pool of excitatory amino acids is stimulated, whereas the release from an exogenously accumulated, possibly cytoplasmic and carrier-mediated, pool is inhibited or slightly stimulated, depending on the external concentration of kainic acid. Kainic acid, in addition, strongly inhibits the high-affinity uptake of L-glutamate and D-aspartate in synaptic terminals. All these effects appear specific for excitatory amino acids, making it likely that they are mediated through specific recognition sites present on the membranes of glutamatergic and aspartatergic terminals. The relevance of the present findings to the mechanism of excitotoxicity of kainic acid is discussed.

Neurotransmitter-related markers in the normal and experimentally lesioned telencephalon of the goldfish

The telencephalon of teleost fish shows high affinity uptake for D-[3H]aspartate, intermediate levels of GABAergic markers and low levels of cholinergic enzymes. Experimental results (resection of the olfactory tracts or unilateral kainic acid administration in the telencephalon) suggest that: the projection from the olfactory bulbs to telencephalic targets is mediated by aspartate and/or glutamate; and a population of GABAergic neurons is present in a telencephalic area which is considered homologous to part of the striatal complex of land vertebrates. From the present results, it appears that the neurochemical approach can be used, in conjunction with neuroanatomical methods, to study evolutionary problems of telencephalic function.

Effects of d,l-propranolol on open field behavior of rats

Rats were administered with different doses of d,l-propranolol or d,l-propranolol plus amphetamine before open-field observations. Results show that d,l-propranolol decreased locomotion and rearing frequencies and increased immobility duration in rats. An antagonism between the effects of amphetamine and d,l-propranolol on general activity of rats was also observed. Results are discussed in the light of a possible interference of the drugs with the activity of either noradrenergic neurons or mid-brain reticular formation.

Evidence for a neurotransmitter role of aspartate and/or glutamate in the projection from the torus longitudinalis to the optic tectum of the goldfish

Different experimental approaches have been used to demonstrate that aspartate and/or glutamate is a transmitter(s) in the projection from the torus longitudinalis to the marginal layer of the optic tectum in the goldfish. Slices of the optic tectum incubated in vitro in the presence of D-[3H]aspartate and processed for light microscopic autoradiography, demonstrated a preferential accumulation of the labeled compound in the marginal layer. Under the same experimental conditions several neurons in the central part of the torus longitudinalis selectively accumulated D-[3H]aspartate. Synaptosome-enriched preparations from the optic tectum showed high-affinity uptake for D-[3H]aspartate and the rate of the uptake was significantly decreased after disconnection from the ipsilateral torus longitudinalis. The same subcellular preparations showed Ca2+-dependent release of previously accumulated D-[3H]aspartate under high potassium stimulation. This release was significantly reduced in preparations from optic tecta 5 days after cutting their connection with the ipsilateral torus longitudinalis. Finally, D-[3H]aspartate injected in the optic tectum retrogradely labeled the fiber systems connecting the marginal layer with the ipsilateral torus longitudinalis as well as neuronal cell bodies in the torus longitudinalis itself. From autoradiographic experiments it was, in addition, noticed that several tectal neurons selectively accumulated D-[3H]aspartate in the cell bodies as well as in main dendritic trunks. This observation suggests tht aspartate and/or glutamate may be a transmitter(s) in some intrinsic circuits and extrinsic projections of the optic tectum.

Apolipoprotein C-II deficiency. The role of apolipoprotein C-II in the hydrolysis of triacylglycerol-rich lipoproteins

Kinetic studies were performed incubating lipoprotein lipase and hepatic triacylglycerol lipase from human postheparin plasma with triacylglycerol-rich lipoproteins from two patients with apolipoprotein C-II deficiency. These lipoproteins differed in their lipid and apolipoprotein composition from normal very-low-density lipoproteins and chylomicrons. The addition of isolated apolipoprotein C-II and normal or apolipoprotein C-II-deficient high-density lipoproteins caused an increase of Vmax and a decrease of the Km for lipoprotein lipase-induced hydrolysis. Hepatic triacylglycerol lipase activity was not influenced by the presence of apolipoprotein C-II in the incubation medium, but was inhibited by increasing amounts of high-density lipoproteins. Binding studies were performed in order to analyze the interactions between lipolytic enzymes, apolipoprotein C-II, and triacylglycerol-rich lipoproteins. Apolipoprotein C-II was, as expected, rapidly taken up by apolipoprotein C-II-deficient very-low-density lipoproteins and chylomicrons when they were incubated with normal high-density lipoproteins or with the purified apolipoprotein. This uptake was inhibited by the addition of increasing amounts of lipoprotein lipase in conditions in which no lipolysis could occur. Binding of lipoprotein lipase to apolipoprotein C-II-deficient very-low-density lipoproteins or chylomicrons was not affected by the addition of apolipoprotein C-II when an excess of triacylglycerol-rich lipoprotein was present. The stability of lipoprotein lipase was also studied. Apolipoprotein C-II and high-density lipoproteins were unable to prolong the half-life of the enzyme activity, while triacylglycerol-rich particles effectively stabilized lipoprotein lipase. We conclude that binding of lipoprotein lipase to the substrate surface is not affected by apolipoprotein C-II. It is more likely that the peptide catalyzes the conversion of lipoprotein lipase from a less to a more active form.

Familial lipoprotein lipase and apolipoprotein C-II deficiency. Lipoprotein and apoprotein analysis, adipose tissue and hepatic lipoprotein lipase levels in seven patients and their first degree relatives

Plasma lipids, lipoproteins, tissue lipoprotein lipase (LPL) and hepatic lipase (H-TGL) were studied in 7 patients with familial hyperchylomicronemia from four different families. Their first-degree relative were also studied. The patients were heterogeneous for the genetic defect; LPL activity was absent in five patients (LPL deficiency) but normal in two. However, these two did not have apo C-II, the physiological activator of LPL (C-II deficiency). There were no significant differences in the clinical picture between patients with LPL deficiency and C-II deficiency. In both mutants, marked hypertriglyceridemia was due to an accumulation of lipoproteins of density less than 1.006 g/ml. The LDL fraction was very reduced and abnormal in composition, presenting a CH/TG ratio of 0.5. The plasma apolipoprotein B (apo B) level was low (67 +/- 5.5 mg/dl) and was transported mainly in the VLDL fraction (26 +/- 3.2 mg/dl) rather than in the LDL fraction (15 +/- 1.4 mg/dl). Very low levels of cholesterol and apolipoprotein A-I in HDL subfractions HDL2 and HDL3 were also recorded. Only 3 out of the 24 first-degree relatives of patients with LPL deficiency showed even a small increase in plasma triglycerides, but 15 had low or low to normal LPL values. H-TGL levels were normal in all subjects. The 4 first-degree relatives of C-II deficiency patients showed normal levels of plasma lipids. LPL and H-TGL, and 2 children of 1 patient showed normal distribution of apo C peptides in their VLDL. A block in chylomicron catabolism, due to the absence of LPL or apo C-II, may lead to a massive accumulation of lipoproteins with a density less than 1.006 g/ml, and a drastic reduction in the LDL and HDL fractions. Low LPL values in the first-degree relatives of LPL deficiency patients might represent a biochemical marker for healthy carriers of LPL deficiency.

Study of differential effects of kainic acid on metabolic rates, utilizing exogenous or endogenous substrates, in rat brain slices

CO2 production from exogenous glucose of cortical, whole hippocampal, and CA3 region hippocampal slices, as well as O2 consumption of whole hippocampal slices, were measured in the presence of different concentrations of kainic acid. A moderate, significant increase of CO2 production was seen only in the CA3 region hippocampal preparation at kainic acid concentrations of 10(-4)-10(-2) M. The O2 consumption, at the expense of endogenous energy stores of whole hippocampal slices, was substantially increased by 10(-3) M kainic acid when the slices were incubated without exogenous glucose. The effect was partly paralleled by the use of high (50 mM) K+ concentration. Some of the possible factors involved in the differential metabolic responses of brain slices to the action of kainic acid are discussed briefly.

Natural history of TCDD-induced liver lesions in rats as observed by transmission electron microscopy during a 32-week period after a single intraperitoneal injection

Forty-two male rats were injected with a single intraperitoneal dose of TCDD in acetone and corn oil and sacrificed after 2, 4, 8, 16, 24, and 32 weeks, to study the long-term effects of a single injection. The liver lesions become progressively worse up to the 16th week and appear thereafter to slowly regress.

Pharmacological manipulation of GABA system does not protect the goldfish optic tectum from the neuroexcitatory and neurotoxic action of kainic acid

Inhibition of GABA transaminase which led to a several-fold increase of GABA levels in the goldfish optic tectum or diazepam pre-treatment, were unable to protect tectal neurons from kainic acid neurotoxicity, as judged by light and electron microscopic observations and by the drop of marker enzymes for neurotransmitters. In an in vitro preparation of tectal slices GABA, added to the incubation medium, had no effect on a metabolic parameter (CO2 production from exogenous glucose) related to the excitatory action of kainic acid. It is concluded that, in the goldfish optic tectum, pharmacological manipulation cannot enhance the activity of GABAergic circuits to the extent necessary to block the neuroexcitatory and neurotoxic action of kainic acid.

Characterization of human chylomicrons

Apolipoprotein and lipid composition of differently sized chylomicrons from healthy volunteers was determined. During their intravasal catabolism the chylomicrons lose triacylglycerol and apolipoproteins. Decreasing particle size results in a loss of apolipoprotein C and apolipoprotein E peptides and an increase in apolipoproteins B and A-I, which constitutes more than 20% of the moiety of small chylomicrons. The C peptides do not seem to behave as a functional entity. Apolipoprotein C-III, the inhibitor of lipolytic activities, is catabolized independently of the other C peptides. Albumin constitutes about 15-25% of the protein moiety of all chylomicrons. The different chylomicron fractions were incubated with lipolytic activities of lipoprotein lipase and hepatic triacylglycerol lipase. At lower substrate concentrations the reactions were of first-order. Large chylomicrons were the favored substrate for both enzymes with Michaelis Menten constant Km = 1.1 mM for hepatic triacylglycerol lipase and 0.48 mM for lipoprotein lipase. After incubation with hepatic triacylglycerol lipase or lipoprotein lipase the shape of chylomicrons differs from that of control particles as demonstrated by electron microscopy. C peptides were completely dissociated and found in the infranatant. In the enzyme assay with triolein gum arabic substrate several apolipoproteins showed an influence on the activities of hepatic triacylglycerol lipase and lipoprotein lipase. Apolipoprotein C-III peptides were the most effective inhibitors of both enzymes. Also, apolipoprotein A-II, A-I and apolipoprotein C-I inhibited lipoprotein lipase activity, whereas only apolipoprotein A-II was able to decrease hepatic triacylglycerol activity.

Effect of kainic acid, glutamate, and aspartate on CO2 production by goldfish tectal slices

For a study of the excitatory effect of kainate, glutamate, and aspartate in the goldfish optic tectum, these substances were tested on the production of CO2 from radioactive glucose in tectal slices incubated in Krebs-Ringer medium for fish. Kainate increased the rate of CO2 production for up to 30 min in a dose-related manner, the effect being maximum at 0.1 mM concentration and decreasing at higher doses. The effect was blocked by ouabain (1 mM) as well as by the substitution of choline for Na+ in the incubation medium. Glutamate and aspartate exerted a less pronounced excitatory effect on CO2 production at higher concentration than kainate. This effect was also abolished by ouabain. Glutamate, added to the medium at a concentration at least 100-fold higher than kainate, partially reversed the increase in CO2 production induced by kainic acid. No similar effect was noticed for aspartate. The supposed glutamate antagonists glutamic acid diethylester (1 mM) and proline (5 mM) did not affect the excitatory action of kainic acid or exert an antagonistic effect towards glutamate. At higher concentration (10 mM) glutamic acid diethylester increased CO2 production, an effect that was, however, ouabain insensitive. Methyltetrahydrofolic acid (1 mM), a substance reported to compete for the kainate receptor, did not inhibit the effect of kainic acid or increase CO2 production.

Experimental infection of European wild swine (Sus scrofa L.) with pseudorabies virus

Experimental infection with pseudorabies virus was carried out by oral exposure of four young wild swine held in contact with two unexposed controls. No disease was observed but virological procedures indicated that the virus was shed in saliva and, in one case, in the nasal discharge, with subsequent infection of the control animals. After slaughter the virus was reisolated from the tonsils but not from lungs and brain. Virus reisolation from the tonsils was obtained in two animals after the throat swabs became negative. Virus neutralizing antibodies were detected.

Neurotoxic effect of kainic acid on ultrastructure and GABAergic parameters in the goldfish cerebellum

Kainic acid administration into the cerebellar dorsal lobe of the goldfish causes selective degeneration of some neuronal types. Stellate and Golgi neurons are very sensitive to the neurotoxin and undergo rapid degeneration. On the basis of their differential responses to kainic acid, Purkinje cells can be divided in two distinct sub-populations (i.e. sensitive and insensitive neurons). The degenerative changes of the Purkinje neurons are in addition remarkably slow in comparison with the same cells in mammals or with stellate and Golgi neurons in the goldfish. Granule cells, as well as the cerebellar afferent fiber system, are not significantly affected. Six days after kainic acid administration, the level of glutamate decarboxylase in the cerebellar dorsal lobe drops to about 40% of the control value. This result suggests that the neurons sensitive to kainic acid neurotoxicity are, at least in part, GABAergic. Light- and electron-microscopic autoradiography of cerebellar elements selectively accumulating [3H]GABA, supports this idea. Moderate decreases of acetylcholinesterase and protein content were also noticed in the kainic acid-treated cerebellar dorsal lobe.

Pharmacological studies on tiadenol in type IV patients. Evidence for a mechanism of action different from other lipid-lowering drugs

Tiadenol [bis(hydroxyethylthio) 1-10 decane], a new absorbable hypolipidemic agent differing in chemical structure from clofibrate and related compounds, was tested in hypertriglyceridemic patients, both responsive and nonresponsive to dietary treatment. Tiadenol administration was remarkably effective in inhibiting fructose induced hypertriglyceridemia in diet responsive type IV patients; it was ineffective in patients with stable, diet refractory, hypertriglyceridemia. The significant reduction of plasma triglycerides (-42%) in sensitive patients, was not accompanied in this study, by the activation of plasma lipoprotein and hepatic lipases. In a second, longer term investigation of stable type IV patients, tiadenol administration resulted in significant triglyceride decreases in the very low density lipoproteins (VLDL) (-45%), as well as in the low and high density lipoproteins (LDL and HDL) (both -25%). The cholesterol content of LDL and HDL was not modified. In VLDL a significant reduction of apoprotein E was observed (from 15.2 +/- 4.9 to 11.9 +/- 5.9% of VLDL proteins). The reported observations are consistent with a difference in the mode of action of tiadenol from that of other lipid lowering agents, particularly of the clofibrate type.

Kainic acid neurotoxicity does not depend on intact retinal input in the goldfish optic tectum

Kainic acid neurotoxicity has been studied in the optic tectum of the goldfish 4 weeks after eye enucleation. The effect of drug treatment has been tested with respect to both neurochemical and morphological parameters. The neurotransmitter-related enzymes, choline acetyltransferase, acetylcholinesterase and glutamate decarboxylase, show about 50% decrease in the deafferented tectum 6 days after kainic acid administration. Relevant morphological alterations of the tectal structure can also be noticed at the same stage. The neurotoxic effects of kainic acid in the deafferented optic tectum are therefore quite similar to the effects of previously noticed for the intact optic tectum of normal fish. Control experiments on the effect of optic nerve degeneration by itself on the levels of the neurotransmitter-related enzymes in the optic tectum, have shown no significant decrease in glutamate decarboxylase, a slight decrease in acetylcholinesterase and a more marked drop in choline acetyltransferase. The findings are discussed with reference to some of the hypotheses advanced in order to explain kainic acid neurotoxicity. It is proposed that the neurotoxic effect of kainic acid after removal of specific excitatory afferents, may vary in different nervous centers depending on differences of the remaining extrinsic connections and of the intrinsic neural circuits.

Effects of insulin and anchorage on hepatocytic protein metabolism and amino acid transport

Insulin partially inhibits endogenous protein degradation in isolated hepatocytes. The inhibition seems to specifically affect the lysosomal pathway of degradation, since it is not additive to the effects of lysosome inhibitors such as propylamine and leupeptin. The insulin effect is potentiated by intermediate concentrations of amino acids, but is largely abolished at high amino acid concentrations which suppress degradation maximally, suggesting that the hormone may exert its effect indirectly by acting upon the more basal amino acid control mechanism. Glucagon, which stimulates protein degradation, similarly displays its effect only in the presence of intermediate amino acid concentrations. The insulin inhibition is not affected by the aminotransferase inhibitor, aminooxyacetate, indicating that it is not due to interference with amino acid metabolism. Protein synthesis furthermore does not seem to be required, since a significant insulin effect can be seen in the presence of the protein synthesis inhibitor, cycloheximide. The issue is, however, complicated by the fact that cycloheximide itself inhibits protein degradation to approximately the same extent as does insulin. Insulin stimulates uptake of the amino acid alpha-aminoisobutyrate (AIB), but not the uptake of valine, indicating a specific stimulation of ‘A’-type transport. Cycloheximide similarly stimulates AIB uptake, without completely obfuscating the transport effect of insulin. Neither protein synthesis, protein degradation, amino acid transport, nor the effects of insulin were affected by cell-to-substratum anchorage (attachment and spreading) in any detectable way.

Energy deposition by proton beams of up to 31 MeV in microscopic volumes

The frequency distributions of energy deposition in microscopic volumes for proton beams of various energies and energy spreads were determined by means of a "rossi type" proportional counter. Tissue equivalent spherical volumes of 0.6, 0.72, 0.80, 1.00, 1.25, 1.50, 1.75, 2.00 micrometer diameter were simulated. Frequency distributions of energy deposition per unit pathlength are reported and their behavior as a function of the simulated pathlength, beam energy and energy spread is discussed. The results indicate that energy deposition distributions in microscopic volumes for protons in the range 8-31 MeV are skewsymmetric distributions with a tail on the high energy side, and that degraded beams behave differently from monoenergetic ones. Dose mean lineal energy values have been quoted for beams used in radiobiological experiments.

Amino acid inhibition of the autophagic/lysosomal pathway of protein degradation in isolated rat hepatocytes

Protein degradation in isolated rat hepatocytes, as measured by the release of [14C]valine from pre-labelled protein, is partly inhibited by a physiologically balanced mixture of amino acids. The inhibition is largely due to the seven amino acids leucine, phenylalanine, tyrosine, tryptophan, histidine, asparagine and glutamine. When the amino acids are tested individually at different concentrations, asparagine and glutamine are the strongest inhibitors. However, when various combinations are tested, a mixture of the first five amino acids as well as a combination of leucine and asparagine inhibit protein degradation particularly strongly. The inhibition brought about by asparagine plus leucine is not additive to the inhibition by propylamine, a lysosomotropic inhibitor; thus indicating that the amino acids act exclusively upon the lysosomal pathway of protein degradation. Following a lag of about 15 min the effect of asparagine plus leucine is maximal and equal to the effect of propylamine, suggesting that their inhibition of the lysosomal pathway is complete as well as specific. Degradation of endocytosed 125I-labelled asialofetuin is not affected by asparagine plus leucine, indicating that the amino acids do not affect lysosomes directly, but rather inhibit autophagy at a step prior to the fusion of autophagic vacuoles with lysosomes. The aminotransferase inhibitor, aminooxyacetate, does not prevent the inhibitory effect of any of the amino acids, i.e. amino acid metabolites are apparently not involved.

Multinucleate cells and micronucleus formation in cultured human cells exposed to 12 MeV protons and gamma-rays

Cultured human cells of the EUE line were exposed to different doses of 12 MeV protons, plated and allowed to grow for 8 days; colonies were then scored for the presences of multinucleate cells and micronuclei. The frequency of both effects is an increasing function of the dose; the evaluated exponents of the dose-response equation (e = bDn) are n = 1.0 %/- 0.1 for multinucleate cells and n = 1.6 +/- 0.1 for micronuclei. By comparison with the results obtained with gamma irradiations, r.b.e. values were obtained for both effects. The correlation between the logarithm of the surviving fraction and the yield of the studied effects has been proved to be statiscally significant.

[Acute granulomatous appendicitis. (Contribution to preventive appendectomy in acute ileitis)]

Starting with one case of acute granulomatous appendicitis of their own observation, the authors review the scant literature on the subject (only 23 published cases to date) and advocate systematic appendicectomy in all isolated appendicular localizations of Crohn's disease. On the grounds that no post-appendicectomy fistulization has ever been reported in such patients, the authors recommend prophylactic appendicectomy also in the far more frequent cases of acute ileitis, to forestall the possibility of evolution into chronic Crohn's disease and the risk of missing a nongranulomatous acute appendicitis appearing with the same clinical symptoms.