Complications of ceftriaxone-associated biliary pseudolithiasis and neprolithiasis: a case report

INTRODUCTION

Ceftriaxone is a wide-spectrum antibiotic frequently used in pediatrics. Biliary pseudolithiasis is a well-known side-effect occurring in 15-57% of cases. However, nephrolithiasis is extremely infrequent, with very few related publications.

CASE REPORT

We present the case of a 9-year-old patient with ceftriaxone-treated complicated acute appendicitis who developed biliary pseudolithiasis and nephrolithiasis. During hospitalization, the patient presented with pseudolithiasis complications such as mild pancreatitis and bilateral ureterohydronephrosis with acute renal failure.

REMARKS

Suspecting ceftriaxone-associated biliary pseudolithiasis and/or nephrolithiasis is key to achieve an early diagnosis and prevent complications such as those reported in this patient. Early discontinuation is essential as an initial treatment measure.

Successful treatment of lichen planus with low-molecular-weight heparin: a case series of seven patients

BACKGROUND

Lichen planus (LP) is characterized by features of a cell-mediated attack on the epidermis by activated T lymphocytes. CD4+ lymphocytes have been shown to produce endoglycosidase (heparanase), which allows them to penetrate into the subendothelial basal lamina. Low-molecular-weight heparin (enoxaparin) has been shown to inhibit expression of heparanase.

METHODS

Seven patients with LP were treated with enoxaparin.

RESULTS

Five experienced a marked improvement with no side effects.

CONCLUSION

Enoxaparin may be an effective treatment for patients with lichen planus.

Chronic and subacute subdural hematoma in the adult population. The Puerto Rico experience

OBJECTIVE

The purpose of this investigation was to study the epidemiology of chronic and subacute subdural hematoma in an adult population and associated factors such as treatment, recurrence, seizures, complications, and outcome.

METHODS

We retrospectively reviewed 267 consecutive cases operated for a suspected diagnosis of chronic or subacute subdural hematoma during a six-year period.

RESULTS

An incorrect diagnosis was done in 12 of the cases (4.5%) giving a total of 255 cases of chronic or subacute subdural hematoma. The mean age of the patients was 68-year old. Two-thirds of the cases were chronic and one-third were subacute. A history of head trauma was identified in 79% of the patients occurring more frequently in the subacute group. The hematoma was bilateral in 16% of the patients. Recurrence occurred in 7.8% of the cases, but there was no significant difference between chronic and subacute cases nor the type of operation done. Postoperative seizures occurred in 6.2% of the cases. Preoperative seizures are not associated to the development of postoperative seizures. A postoperative intracerebral hematoma occurred in 2.7% of the patients and was associated in most of the cases with a poor outcome. The morbidity rate was 9% and the mortality rate was 0.9%. Outcome is good in 95% of the patients.

CONCLUSIONS

Chronic subdural hematoma occurs more frequently than subacute subdural hematoma. Surgical treatment modality and the use of a drain do not change the recurrence rate. Preoperative seizures are not associated to the development of postoperative seizures. The use of postoperative prophylactic antiepileptic drugs does not decrease the postoperative seizure rate even in the alcoholic patient, therefore, their prophylactic use is not indicated.

Sudden appearance of multiple brain lesions in Aids after a cerebral biopsy. Case report

A unique case of cerebral toxoplasmosis which had an acute appearance of multiple discrete lesions following a biopsy and its neuroradiological findings are reported in detail. Possible pathophysiological mechanism are presented.

Cyclic nucleotide phosphodiesterases and methyltransferases in purified lymphocytes, monocytes and polymorphonuclear leucocytes from healthy donors and asthmatic patients

Cyclic nucleotide phosphodiesterase and phospholipid N-methyl-transferase activities were simultaneously measured in purified polymorphonuclear cell-, mononuclear cell-, lymphocyte- and monocyte-homogenates from control subjects, from patients with atopic asthma and from patients with non-atopic asthma. Whereas cyclic AMP and cyclic GMP phosphodiesterase activities were found to be about 10-fold lower in polymorphonuclear than in mononuclear cells, phospholipid N-methyltransferase proved to be rather similar in each cell type from control donors. Cyclic AMP phosphodiesterase and phospholipid N-methyltransferase were significantly decreased in polymorphonuclear cells and monocytes from asthmatic patients compared with the control group while cyclic GMP phosphodiesterase was significantly impaired only in the monocyte subpopulation.

Adenosine analogs elevate N-acetylserotonin and melatonin in rat pineal gland

Adenosine, S-adenosyl-L-homocysteine, adenosine analogs such as 5'-N-ethylcarboxamidoadenosine and mioflazine, a nucleoside transport inhibitor, injected intraperitoneally at 09.00 h during the light period increased melatonin levels in the pineal gland of the rat. The largest increase occurred with 1 mg/kg 5'-N-ethylcarboxamidoadenosine. A representative time-response curve with 5'-N-ethylcarboxamidoadenosine (1 mg/kg) showed a maximal peak of N-acetylserotonin and melatonin 2 and 4 h after injection, respectively. These results are discussed in relation with the possible modulation through A2 receptors of melatonin synthesis in the pineal gland.

Isolation of similar rolipram-inhibitable cyclic-AMP-specific phosphodiesterases from rat brain and heart

A cyclic AMP phosphodiesterase form of rat brain cytosol was purified by means of affinity chromatography on an immobilized analog of the specific inhibitor rolipram, followed by an exclusion chromatography step. The resulting preparation presented two protein bands in polyacrylamide gel electrophoresis, both with phosphodiesterase activity. Kinetics of cyclic AMP hydrolysis by the purified enzyme proved of the Michaelis type, with a Km of 3 microM, while hydrolysis of cyclic GMP displayed anomalous negatively cooperative kinetics. At micromolar concentrations, this enzyme from hydrolyzed highly specifically cyclic AMP (50-fold faster than cyclic GMP). Cyclic GMP proved a poor competitor of cyclic AMP hydrolysis (Ki 1.04 mM). The neurotropic compound, rolipram, strongly inhibited the enzyme, in a competitive manner (Ki 0.9 microM). This enzyme displayed a molecular mass of around 44 kDa as determined by exclusion chromatography, but two molecular masses of 42 kDa and 89 kDa were observable by electrophoresis on a polyacrylamide gradient gel, compatible with an equilibrium between dimeric and monomeric forms. Isoelectric focusing of the preparation gave rise to two activity peaks of pI 4.8 and 6.7, with identical properties, probably representing two charge isomers of the same protein. An enzyme prepared from rat heart cytosol by the same techniques as for brain phosphodiesterase isolation shared numerous characteristics with the enzyme of cerebral origin, suggesting identity of the rolipram-sensitive form between the two tissues. Since the rolipram-sensitive form detected in crude brain preparations markedly differs from the above-described isolated enzyme, both by its molecular mass in exclusion chromatography and by its pI, it is suggested that an alteration of the native protein, due to dissociation of putative subunits, occurs during the purification procedure.

Identification of adenosine receptor in rat pineal gland: evidence for A-2 selectivity

We have examined the binding of the adenosine agonist radioligands [3H]cyclohexyladenosine [( 3H]CHA), R-N6-[3H]phenylisopropyladenosine [( 3H]R-PIA), and 5'-N-ethylcarboxamido[3H]adenosine [( 3H]NECA) to membranes prepared from rat pineal gland. The results showed that the A-1-selective ligands (CHA and R-PIA) had less than or equal to 10% specific binding. By contrast, [3H]NECA, a nonselective A-1/A-2 ligand, gave 72% specific binding of the total binding. This specific binding was insensitive to cyclopentyladenosine (50 nM) or R-PIA (50 microM). To characterize this binding, we used the N-ethylmaleimide pretreatment method. Under these conditions, this binding was of high affinity with a KD of 51 +/- 10 nM and an apparent Bmax of 1,060 +/- 239 fmol/mg of protein. Specific binding was unaffected by the presence of MgCl2 (10 mM) but was sensitive to guanylylimidodiphosphate (100 microM) (-25%), a result suggesting the involvement of an N-protein mechanism in the coupling of the adenosine receptor labeled by [3H]NECA to other components of the receptor complex. The rank of activity of adenosine analogues in displacing specific [3H]NECA binding was NECA greater than 2-chloroadenosine greater than S-adenosyl-L-homocysteine greater than CHA. Binding was also displaced by 3-isobutyl-1-methylxanthine (IC50 = 23.6 microM). These findings are consistent with the selective labeling by [3H]NECA of an A-2-type adenosine receptor in rat pineal membranes.

Cardiovascular action of penta-O-ethylquercetin in the rat

Intravenous (i.v.) administration of penta-O-ethylquercetin (PQ) dissolved in glycerolformal (GF) induced a rapid and transient fall in arterial blood pressure of rats. The mechanism appears rather complex. Beside its inhibitory properties toward cardiac cyclic AMP phosphodiesterase, the drug seems to lower the adrenergic tone, thus acting both at the central (stimulation of the cardiomoderator medullary center) and peripheral (partial blockade of postsynaptic alpha-adrenergic receptors, decrease in noradrenaline liberation) levels. Repeated i.v. administration of variable dosages of PQ caused a decrease in the hypotensive effect of PQ/GF which might be related to a tachyphylaxy phenomenon. In marked contrast, continuous i.v. infusion of PQ/GF progressively increased arterial blood pressure, which very likely involves a quite different mechanism of action.

Flavonoid modulation of protein kinase C activation

The flavonoid quercetin exhibited a biphasic effect on calcium and phospholipid-dependent protein kinase (protein kinase C) activity from rat brain and pig thyroid. At a low concentration (10(-7) M) quercetin stimulated the enzyme activity whereas at higher concentrations quercetin was inhibitory. By contrast the synthetic penta-0-ethylquercetin stimulated protein kinase C activity in a dose-dependent manner. When fresly dispersed pig thyroid cells were treated with penta-0-ethylquercetin or 12-0-tetradecanoylphorbol 13-acetate (TPA), a 50% decrease of the cytosolic protein kinase C activity was observed. These results suggest that the lipophilicity as well as other structural determinants may be crucial for the ability of flavonoids to regulate (inhibit or activate) the enzyme activity.

Inhibition of the different cyclic nucleotide phosphodiesterase isoforms separated from rat brain by flavonoid compounds

A series of synthetic pentasubstituted analogs of quercetin were evaluated for their ability to inhibit the various phosphodiesterase isoforms resolved from rat brain cytosol by isoelectric focusing. All the tested compounds were more potent in inhibiting the calcium plus calmodulin-independent isoforms than the dependent ones. Out of the two calcium-independent cyclic AMP-specific isoforms present in brain preparations, the Rolipram-sensitive enzyme proved to be the most sensitive to flavonoid inhibition. In contrast with the antidepressant compound Rolipram which is totally devoid of anticalmodulin property, these flavonoid derivatives exhibited anticalmodulin activity as illustrated by their higher inhibitory potency toward the calmodulin-dependent isoform in the presence of calcium plus calmodulin than in the presence of EGTA and by the ability of [3H] penta-O-ethylquercetin to bind to calmodulin in a calcium-dependent way.

Kinetic and biochemical properties of CTP:choline-phosphate cytidylyltransferase from the rat brain

In order to investigate the mechanisms involved in some brain disorders at the membrane level, we studied the kinetics and biochemical properties of brain CTP:choline-phosphate cytidylyltransferase (EC 2.7.7.15), the rate-limiting enzyme of the two-step biosynthesis of phosphatidylcholine. This enzyme catalyzes the biosynthesis of CDPcholine from choline phosphate and CTP. We found that its subcellular localization (mainly in microsomal and cytosolic fractions) was different from that of phosphatidylethanolamine N-methyltransferase (EC 2.1.1.17), the enzyme of the alternative pathway for phosphatidylcholine synthesis. CTP:choline-phosphate cytidylyltransferase showed a Km of 10 mM for CTP and 0.3 mM for choline phosphate and exhibited a random mechanism. CDPcholine, the reaction product, was a competitive inhibitor of choline phosphate and CTP utilization and had a Ki of 0.090 mM. Both particulate and soluble enzymes required Mg2+ and exhibited an optimal pH at about 7. Cytosolic activity was enhanced by addition of unsaturated fatty acids or phospholipids extracted from brain membranes. Such an enhancement was increased with the centrifugation time used for preparing the soluble enzyme.

Changes in the rat sleep-wake cycle produced by D,L-beta-(1-naphthyl)alanine, a tryptophan analog

The effects of i.p. injections of D,L-beta-(1-naphthyl)alanine, a synthetic analog of tryptophan were tested on the rat sleep-waking cycle. Administration of 30, 60 and 120 mg/kg resulted in a significant increase in slow-wave sleep (SWS) and a decrease in paradoxical sleep (PS). These modifications were dose-dependent. These results were compared with those previously obtained with L-tryptophan and several analogs and discussed in relation with possible changes in central serotonergic activity.

Comparison of cyclic nucleotide phosphodiesterase isoforms from rat heart and bovine aorta. Separation and inhibition by selective reference phosphodiesterase inhibitors

The resolution as well as the biochemical properties of the multiple molecular forms of cyclic nucleotide phosphodiesterase, in a given tissue, may be strongly dependent upon experimental conditions of preparation (extraction of crude enzyme from tissues and fractionation procedures). In the present study, we compare the different molecular forms of cardiac (rat heart ventricle) and vascular (bovine aorta) phosphodiesterase isolated from crude extracts prepared either in sucrose medium or in hypotonic medium (in the presence of protease inhibitors and ion chelators) using two different fractionation procedures: isoelectric focusing on flat gel bed and DEAE-Trisacryl anion exchange chromatography. Both the calmodulin-dependent and the cAMP-specific forms exhibited close IEF and chromatographic patterns and showed similar sensitivities towards reference inhibitors regardless of the tissue of origin. In marked contrast, the cGMP-specific isoform notably differed from one to another tissue with respect to its biochemical properties (only the cardiac tissue being capable of stimulation by cGMP) and sensitivities to xenobiotics. Thus the possibility exists that pharmacological agents may modulate phosphodiesterase activity differently in cardiac and vascular target tissues.

Morphometry of right ventricular papillary muscle in rat during development and regression of hypoxia-induced hypertension

Morphometric analyses of the right ventricular papillary muscle, as well as measurements of right ventricular pressure and weight, were carried out in the rat during the development and recovery of hypoxic pulmonary hypertension. Animals were divided into hypoxic and normobaric control groups. The hypoxic rats were placed in hypobaric chambers for 1, 2, and 3 wks; and after 3 wks exposure, subgroups of hypoxic rats were allowed to recover in normoxia for 1 to 9 wks. Hematocrit (HCT) and right ventricular systolic pressure (RVSP) were measured prior to sacrifice. The heart was perfused, and the right ventricle (RV) was separated from the left ventricle and septum (LV+S) and weighed. The papillary muscles were dissected and processed for ultrastructural morphometry. Results showed that HCT, RVSP, and RV weight increased in the rats during the hypoxic exposure and then gradually returned to control levels after 3 to 4 wks of normobaric recovery. The papillary muscle of the hypoxic rats showed increased volume density of interstitium, increased diameter and cross sectional area of the cardiac myocytes, reduced volume density of mitochondria, and reduced mitochondria to myofilament ratio. During normoxic recovery, these morphometric indices returned toward control values at various periods of time ranging from less than 3 wks to 9 wks. The results indicate that the adaptive ultrastructural changes of the papillary muscle in RV hypertrophy paralleled the RVSP changes, and also demonstrate the reversibility of these changes in ambient oxygen.

Cyclic nucleotide phosphodiesterase activity in the quail oviduct: hormonal regulation and involvement in estrogen-induced growth

A previous study has shown that cAMP was involved in estrogen-activated growth in the quail oviduct. The present study was undertaken to investigate the hormonal regulation of 3',5'-cyclic nucleotide phosphodiesterase activity in the oviduct. Tamoxifen, an antiestrogen compound, and 3-isobutyl-1-methylxanthine, an inhibitor of phosphodiesterase, were also used to determine the relationship between estradiol-induced cell proliferation and cAMP phosphodiesterase activity. Cyclic nucleotide phosphodiesterase was almost completely restricted to the cytosolic fraction (108,000 X g supernatant) of the quail oviduct homogenate. By affinity chromatography on immobilized calmodulin, we separated and partially characterized three different forms of the enzyme. They differed in their cyclic nucleotide specificities, kinetics, and sensitivity to calmodulin. In vivo, estradiol benzoate (EB) modulated crude cytosolic phosphodiesterase activity. cAMP and cyclic-GMP hydrolyzing activities increased between 12 and 48 h after a single injection of EB and then declined to return to control value by 96 h. Estrone, 17 alpha-estradiol, progesterone, and testosterone were ineffective, while estriol slightly increased cyclic-GMP hydrolyzing activity. When administered with EB, tamoxifen drastically increased oviduct cAMP concentration while it completely inhibited oviduct growth and the activation of cAMP phosphodiesterase induced by EB alone. Moreover, 3-isobutyl-1-methylxanthine produced a dose-dependent inhibition of oviduct cell proliferation when given with EB. These results demonstrate that the activation of cAMP phosphodiesterase after an injection of EB and the subsequent decrease in oviduct cAMP concentration are necessary for the epithelial cells to achieve their proliferative cycle.

Effect of estrogen on adenosine 3'5',cyclic monophosphate in quail oviduct: possible involvement in estradiol-activated growth

Previous studies have shown that estradiol indirectly stimulated the proliferation of oviduct epithelial cells in the quail. The present study was undertaken to investigate the effects of estradiol and other steroid hormones on the cAMP concentration. The ability of forskolin, a specific activator of the catalytic subunit of adenylate cyclase, to induce oviduct cell proliferation and specific protein synthesis (progesterone receptor) in the absence of estrogen was also tested. Administration of estradiol benzoate (EB) to immature female quails produced a transient surge in oviduct cAMP concentration. After EB injection, cAMP concentration increased by 36.7% after 6 h and returned to control values after 12 h. This rise in oviduct cAMP concentration preceded the beginning of DNA synthesis. The same effect was observed even in the absence of increased plasma estradiol, when the hormone was perfused through the hepatic portal vein. Estriol, estrone, and testosterone failed to elevate cAMP concentrations. After repeated EB injections, the oviduct cAMP concentration declined below the control value (-66% after 72 h). A similar drop in the cAMP concentration was observed in developing quails during the proliferative phase of the luminal epithelial and glandular cells. Administration of forskolin to immature female quail pretreated with EB rapidly increased the oviduct cAMP concentration, induced a burst of DNA synthesis, and shortened the prereplicative period. In addition, forskolin administration did not increase the progesterone receptor concentration. These results demonstrate that cAMP is involved in the mechanism by which estradiol indirectly stimulates oviduct epithelial cell proliferation in the quail. The events that may take place during the prereplicative period and the antiproliferative effect of progesterone through a sustained increase in the cAMP concentration in the oviduct are discussed.

B16 melanoma development in black mice exposed to low-level microwave radiation

The effect of low-level microwave exposure, 2,450 MHz, at a power density of 1 mW/cm2 and specific absorption rate of 1.2 mW/g, continuous waves (CW) or pulsed waves (PW), 2.5 h/day, 6 sessions/week until death (up to 690 h of irradiation), has been studied in black C57/6J mice with B16 melanoma. The results show that no significant effects are observed on tumor development or on survival times compared to controls, or between CW- and PW-treated animals.

Interaction of propranolol with GABA stimulated diazepam binding to rat brain membranes

1. In the case of an intraperitoneal propranolol injection to rats (25 mg/kg), there was no modification in benzodiazepine and gamma-amino-butyric acid recognition sites since [3H]diazepam or [3H]-muscimol binding was not affected. 2. There was an increase in GABA stimulated-diazepam binding (100%, statistical risk lower than 1%). 3. This last result suggests that propranolol treatment can stimulate GABA-benzodiazepine receptor coupling.

Effects of an extract of Ginkgo biloba on the 3',5'-cyclic AMP phosphodiesterase activity of the brain of normal and triethyltin-intoxicated rats

For clarification of the beneficial effects of the extract of Ginkgo biloba (EGB) on triethyltin (TET) toxicity in rats, the phosphodiesterase (PDE) activities of the cerebral tissue were measured under in vitro and ex vivo conditions. Under in vitro conditions, low concentrations of EGB (0.25-4.0 mg/L) activated the enzyme, whereas after higher concentrations (5-250 mg/L), dose-dependent inhibition of the enzyme activity was observed. In the lower concentration range, the extract also partially restored the high-affinity PDE activity (measured with 0.25 microM cyclic AMP) of the particulate fraction of the brain inhibited by TET in vitro. In contrast, the inhibitory influence of TET on the low-affinity PDE activity (measured with 50 microM cyclic AMP) of the particulate fraction was enhanced by the extract. Although treatment with a single large dose of EGB lowered the particulate PDE activities of the brain of normal rats, no effects of the extract could be detected in animals after repeated daily administrations of EGB during a 4-day period. Curative treatment of the TET-intoxicated rats with EGB during a 7-day period accelerated the recovery of the edematous state of the white matter caused by the intoxication and also normalized the lowered PDE activity of the particulate fraction of the edematous brain tissue. Furthermore, when preventively administered, EGB counteracted both the edema formation and the fall in PDE activity observed with treatment by TET alone. These observations strongly suggest that some beneficial effects of EGB might be due to its modulating influences on cellular cyclic AMP levels via activation of membrane-bound PDE.

Increase of in vitro brain [3H]muscimol binding after L-homocysteine administration to rat

L-Homocysteine intraperitoneal injections to the rat induced 50-70% inhibition of phosphatidyl-N-methyltransferase activity. A 30-40% increase of muscimol (a gamma-aminobutyric acid (GABA) agonist) binding was observed; Scatchard plot analysis showed an increase of the number of sites. [3H]Diazepam binding was not modified.

Comparison of basal and noradrenaline stimulated methylation of chloroform-extractable products in synaptosomal preparations from the rat brain

Noradrenaline addition increases (S-adenosyl-L-methionine)-methylation of chloroform extractable products in the rat brain synaptosomal preparation. The characteristics of this methylation (MgCl2 dependence, S-adenosyl-L-methionine concentration dependence) are different from those of phosphatidylethanolamine methylase. The greatest increase was induced by noradrenaline in the 10(-4) M concentration range; preincubation of noradrenaline with the membranes, before S-adenosyl-L-methionine addition, was necessary. The TLC analysis of chloroform extractable products showed that: methylation of phosphatidylethanolamine derivatives was increased and the production of another unknown product (corresponding to that described by Wazer et al., Life Sci. 32, 2535, 1983) was more enhanced.

Phosphatidylethanolamine methyltransferase and cAMP, cGMP phosphodiesterases in lymphocytes and monocytes in sarcoidosis

Among the various hypotheses proposed to explain immune cell defect in sarcoidosis, we examined thoroughly that of Faguet who described abnormalities of signal transmission at lymphocyte membrane level. Phosphatidylethanolamine methyltransferase and cAMP cGMP phosphodiesterases were studied in blood lymphocytes and monocytes from 8 subjects with sarcoidosis disease. Phosphatidylethanolamine methyltransferase (PMT1) plays an important regulatory role in membrane signal transmission. cAMP and cGMP phosphodiesterases (PDE) regulate cytoplasmic cyclic nucleotide levels and so participate in the modulation of the cell cycle. We observed a decreased PMT1 activity in lymphocytes and monocytes and a decreased cAMP and cGMP PDE activities in monocytes. It is not now possible to say if these abnormalities are primary or secondary. Whatever the origin of this dysfunctioning, these results evoke simultaneous disturbances of membrane signal transmission and cell cycle in monocytes and membrane abnormalities in lymphocytes. These abnormalities could explain some immune cell defects in sarcoidosis disease.

Modification by S-adenosyl-L-homocysteine of norepinephrine in-vitro uptake in rat brain homogenates

After incubation of rat brain homogenates with S-adenosyl-L-homocysteine (10 microM), norepinephrine uptake was modified according to the norepinephrine concentration. For low-range concentrations, uptake was lowered, whereas for high-range concentrations, uptake was increased.

Solubilization and partial purification of S-adenosyl-L-homocysteine binding proteins from the rat brain

Rat brain proteins presenting high-affinity binding of S-adenosyl-L-homocysteine were solubilized and purified. Extraction of binding protein was carried out in the presence of Triton X-100 and 1 M NaCl; this solubilized fraction exhibits similar kinetic properties than the membrane proteins. Purification was performed using affinity chromatography on S-adenosyl-L-homocysteine carboxyhexyl Sepharose 48 conjugate. The analysis of the affinity gel eluate by SDS-PAGE showed high purification ratios for two proteins exhibiting 54 and 68 kDa. Three activity peaks were separated when solubilized membrane proteins were submitted to isoelectric focusing; the activity peaks corresponded to proteins of pH1 6.0, 6.5, and 7.2. SDS-PAGE separation of proteins contained in each peak showed protein aggregation; a 54-kDa subunit was present in each aggregate. Solubilized membrane proteins were labeled by photoaffinity labeling with tritiated S-adenosyl-L-homocysteine; the 54- and 68-kDa proteins were found among the specifically labeled proteins. Finally, according to the previous data from the literature, the purified S-adenosyl-L-homocysteine binding proteins do not seem to be the same as adenosine receptors or phosphatidylethanolamine-N-methyltransferase.

[Methylation of membrane phospholipids of alveolar macrophages in pulmonary sarcoidosis and diffuse interstitial pulmonary fibrosis]

Alveolar macrophage plays an important role in alveolitis pathogenesis and lung fibrosis process. Macrophages exhibit plasmic membrane biochemical modifications during cell activation. Phospholipid methylation is involved during plasmic membrane stimulation. Phosphatidylethanolamine methyltransferase I was measured in alveolar macrophage membrane from normal subjects and patients presenting with pulmonary sarcoidosis or interstitial lung fibrosis. We observed increased enzyme activity among sarcoidosis subjects with high intensity lung alveolitis and normal subjects receiving immunostimulating treatment (RU 41740). The role of membrane phospholipidic modifications in granulomatous process is discussed.

Alveolar macrophage membrane phospholipid methylation in sarcoidosis and hypersensitivity pneumonitis

Methylation of phospholipids seems to be an essential step in the recognition and transduction of regulatory signals by eukaryotic cells. Phosphatidylethanolamine methylation was compared in alveolar macrophage membrane from patients presenting with pulmonary sarcoidosis or hypersensitivity pneumonitis and control subjects. Phosphatidylethanolamine methyltransferase (PMT1) activity was determined by various measures of incorporation of tritiated methyl group from (3H) S-adenosyl-L-methionine in membrane phospholipids. Tritiated methyl group incorporation in macrophage membrane was higher in some patients presenting with sarcoidosis or hypersensitivity pneumonitis, than in controls. PMT1 activity was found to be higher in sarcoidosis patients with a positive gallium lung scan. As lipids play an important role during macrophage activation and cell interaction, although a wide heterogeneity was observed in PMT1 activity, increased membrane phospholipid methylation seems to be an important feature in pulmonary diseases where macrophages are involved.

Magnum morphogenesis during the natural development of the quail oviduct: analysis of egg white proteins and progesterone receptor concentration

The histological development of the quail oviduct and the changes in concentrations of progesterone receptor, ovalbumin, conalbumin, ovomucoid and ovoglycocomponents are analyzed during the period spanning 7-35 days of age. The initiation of luminal epithelial cell proliferation is the first event of magnum growth. The epithelial cells begin to evaginate into subepithelial stroma and form tubular glands. Meanwhile, luminal epithelium starts cellular pleomorphism through ciliogenesis. No egg white proteins are detectable in the developing glands; at the same time, the concentration of the progesterone receptor increases from about 5500 sites/cell to 30,300 sites/cell. Tubular gland cells then begin to synthetize and accumulate egg white proteins, mucous cells differentiate in the luminal epithelium, and the cell proliferation decreases and finally stops. Compared with earlier studies dealing with the blood levels of estrogen and progesterone in developing quails during the same period, and the cellular changes induced in the oviducts of ovariectomized and ovariectomized-hypophysectomized quail by exogenous steroids, these results distinguish between the cellular responses that are physiologically controlled by estradiol and other responses that have multihormonal regulation.

Purification of cAMP-specific phosphodiesterase from rat heart by affinity chromatography on immobilized rolipram

Affinity chromatography on a cAMP-specific phosphodiesterase inhibitor related to Rolipram, immobilized to AH Sepharose allowed to perform an efficient purification of the cAMP-specific phosphodiesterase isoenzyme from rat heart cytosol (102-fold purification with a 35% yield in a single step). This affinity chromatography involved a biospecific interaction since a 2 mM cAMP elution step at 30 degrees C was necessary for releasing the cAMP specific form tightly bound on the affinity gel. The cAMP eluate fraction exhibited a high specificity towards cAMP (cAMP/cGMP hydrolysis ratio 5-10), a marked sensitivity to Rolipram inhibition and could be resolved in two cAMP-specific, highly Rolipram-sensitive peaks of pI 6.7 and 4.8 by IEF on polyacrylamide gel plates. Protein stain of the IEF gel revealed a single band at pI 6.7.

Possible involvement of the S-adenosyl-L-homocysteine metabolites, adenosine and L-homocysteine, in sleep in rats

The effects of i.p. injections of adenosine (Ado) and homocysteine at 17.00 h were tested on the rat sleep-waking cycle. Administration of 7 and 50 mg/kg of Ado resulted in a significant increase in sleep in otherwise saline male rats during the environmental-dark period (18.00-06.00 h). Increments of paradoxical sleep were maximal with the smaller dose of Ado. The larger dose increased slow-wave sleep during the first 2 h. In contrast, administration of homocysteine (7 mg/kg) had no effect while a larger dose (50 mg/kg) induced a slight but significant long-lasting decrease of paradoxical sleep. These results were compared with those previously obtained with S-adenosyl-L-homocysteine (SAH), an intracellular precursor of Ado and L-homocysteine. It is proposed that the reported hypnotic action of exogenous SAH in rats could be mediated by Ado receptors.

Pharmacokinetics and metabolism of S-adenosyl-L-homocysteine, in rats and dog

Tissue distribution, metabolism and excretion of 14C-S-adenosyl-L-homocyteine were investigated in rat after oral and intraperitoneal administration. The radioactivity was distributed rapidly to the tissues. The urine was the major route of excretion: respectively 32% and 52% of radioactivity were excreted in 48 h urine after oral and intraperitoneal administration. Analysis of urine by HPLC showed that the major part of the radioactivity could be identified as uric acid. Absorption and pharmacokinetic parameters were determined in dog after oral and intravenous administration. The experimental data were fitted to a biexponential equation from a two-compartment open model.

Modulation of the cardiac membrane-bound cyclic nucleotide phosphodiesterase: inhibition due to a contamination of TLC purified S-adenosyl-L-[methyl-3H] methionine by Zn++ ions

Cardiac membranes pretreated with S-Adenosyl-L-[methyl-3H] methionine([3H] SAM) purified on TLC silica gel 60 F254 plates exhibited a marked decrease in cyclic AMP and cyclic GMP phosphodiesterase activity. However, this inhibition did not appear when membranes were incubated with either [14C] SAM or unlabelled SAM. We showed that, during the TLC purification of [3H] SAM, which involved an acidic elution step, minute amounts of the fluorescent indicator F254 (Zn sulfur) were eluted. The contaminating Zn++ ions strongly inhibited cyclic nucleotide phosphodiesterase activity and phospholipid methylation with I50 values in the micromolar range.

Phospholipid methylase activity, [3H]S-adenosyl-L-homocysteine binding, and S-adenosyl-L-methionine and S-adenosyl-L-homocysteine levels in rat brain during maturation

The changes in activity of phospholipid methyltransferase I and [3H]S-adenosyl-L-homocysteine ([3H]SAH) binding were determined in cortical membrane preparations from newborn rats and rats 1, 2, and 8 months old. The activity of phospholipid methyltransferase I and the [3H]SAH binding were significantly greater (respectively, +30 and +40%) in newborn rats than in 1-, 2-, and 8-month-old rats. The methylated products at days 1 and 30 were identical. These changes in methyltransferase activity may be correlated with variations in concentration of S-adenosyl-L-methionine (SAM) and SAH. The endogenous SAM level was higher and the SAH level was lower in newborn compared with adult rats. These data suggested that the processes of methylation were favored in newborn rats. The modifications observed after treatment with L-homocysteine reinforced this hypothesis.

Activity of cyclic AMP phosphodiesterase and methyltransferases in leukocyte membranes from allergic patients

Cyclic AMP metabolism and methylation of phospholipids are central events which occur at the membrane level. Since a dysfunction of cell membranes seems to characterize some allergic diseases, we investigated cyclic AMP phosphodiesterase and methyltransferase activities in leukocyte membrane fractions obtained from healthy volunteers and from allergic patients. The allergic group presented a significantly decreased methyltransferase activity compared with a control group, whereas cyclic AMP phosphodiesterase and noradrenaline (NA)-stimulated methyltransferase were found to be increased with respect to the control group. A significant correlation has been found between cyclic AMP phosphodiesterase and NA-stimulated methyltransferase with both control and allergic subjects, which suggests close relationships between these two enzymes within the cell membrane.

Decreased adenosine cyclic 3',5'-monophosphate phosphodiesterase activity in rat brain following triethyltin intoxication

The possible involvement of cerebral cAMP-phosphodiesterase (PDE) in the intoxication and brain edema formation after exposure to triethyltin (TET) has been studied in vitro and in vivo in the rat. In vitro studies showed an irreversible inhibition of the particulate and soluble phosphodiesterase activities. In vivo, both high i.v. single dose and repeated oral administration of low TET doses led to a significant decrease of the particulate activities. Phosphodiesterase inhibition preceded edema formation. The soluble activities were less influenced and their inhibition could be a consequence of the edema formed in the brain tissue rather than of a TET direct action upon the enzyme. Kinetic analysis of the brain particulate enzyme from the TET-treated rats showed a significant decrease in the Vmax of the substrate high affinity enzyme form when compared to controls.

Diurnal variations of s-adenosyl-l-methionine and adenosine content in the rat pineal gland

S-adenosylmethionine and adenosine levels in the rat pineal gland were determined by high-performance liquid chromatography after fractionation of the pineal extracts. The concentration of S-adenosylmethionine follows a circadian rhythm and is about three times higher during the day (2.5 nmol/gland) than the night (1.1 nmol/gland). The variations in the level of adenosine are apparently more complex. Over the 24 hours period there are two maxima at 03.00 (120 pmol/gland) and 15.00 hrs (100 pmol/gland) and one minimum at 09.00 hrs (50 pmol/gland). In addition, only an ultradian rhythm with a period of 12 hrs and an acrophase of 3 hrs can be evinced by computer analysis.

Effect of S-adenosyl-L-homocysteine upon sleep in p-chlorophenylalanine pretreated rats

S-Adenosyl-L-homocysteine (7 mg/kg), administered to PCPA-pretreated rats, was able to restore normal SWS and PS quantities, as well as circadian rhythms. This effect was at its maximum when SAH was injected 48 h after PCPA (400 mg/kg). These results are discussed in terms of post-synaptic synergetic control by SAH of serotonergic and noradrenergic nerve terminals via the periventricular system and caudal medulla in relation to environmental input.

Activation of the cyclic nucleotide phosphodiesterase from rat heart cytosol by phospholipase C

Phospholipase C (clostridium perfringens) significantly increased the cyclic nucleotide phosphodiesterase activity of a crude 105 000 g supernatant from rat heart. This activation only concerned the basal activity of cyclic GMP phosphodiesterase determined with 0.25 microM cyclic GMP as substrate, in the presence of EGTA, whereas stimulation was found to be independent of EGTA when phosphodiesterase activity was measured with 0.25 microM cyclic AMP. Similar qualitative results were found for the three cytosolic forms of phosphodiesterase separated from rat heart supernatant by isoelectric focusing. Supplementary experiments provided evidence that the activation of the cyclic AMP-specific phosphodiesterase was attributable to Phospholipase C activity and not to contaminating protease(s). In contrast, the stimulation of the cyclic GMP phosphodiesterase activity appeared to be largely dependent on the proteolytic activity of commercial Phospholipase C. Phosphatidic acid also significantly increased the cyclic AMP phosphodiesterase activity of the rat heart cytosol. These results suggest that the activation of cardiac cyclic AMP phosphodiesterase may be related to changes in phospholipid metabolism, notably the accumulation of phosphatidate, and relevant to physiological regulatory processes.

Autoradiographic localization of [14C]8-S-adenosyl-L-homocysteine in rat brain

Following intracarotid injection of [14C]8-S-adenosyl-L-homocysteine ( [14C]SAH) in the rat, radioactivity was localized by autoradiographic detection in the circumventricular organs, such as the pineal gland, choroid plexuses and area postrema, which lie outside the blood-brain barrier. HPLC analysis indicated a decrease of [14C]SAH radioactivity in these structures from 1 to 45 min, after injection. These results are discussed and related to the known pharmacological properties of SAH.

Development of the oviduct in quail during sexual maturation in relation to plasma concentrations of oestradiol and progesterone

The macromolecular content (DNA, soluble proteins and ovalbumin) of the magnum and the plasma concentrations of oestradiol and progesterone were studied during sexual development of the Japanese quail. Rapid growth and differentiation of the magnum began between 21 and 28 days of age and rapidly reached the laying stage in about 20 days. This rapid change in magnum size occurred in a stepwise manner: cellular proliferation was observed first, followed by the synthesis and accumulation of specific proteins. Just before and during magnum growth, plasma oestradiol and progesterone concentrations followed different patterns: the initiation of epithelial cell proliferation was preceded by a sharp decrease in plasma progesterone. Maximum cell division occurred while plasma progesterone levels continued to decrease slightly; at the same time, oestradiol increased from 0.098 to 0.453 nmol/l. The decrease and finally the cessation of cell proliferation and the concomitant increase in ovalbumin concentration were related to almost constant levels of plasma oestradiol and increasing levels of plasma progesterone. Further development of the magnum (above 2.3 g weight) involving only the accumulation of secretory products was associated with an increased value of plasma progesterone. These data are consistent with the hypothesis that there are multiple hormonal signals controlling cell proliferation and synthesis of egg-white proteins in the oviduct. Progesterone may be one of the key signals that regulates the initiation of oviduct growth in the quail.

Modulation by S-adenosyl-methionine and S-adenosyl-homocysteine of the human leucocytes histamine release

Methylation of membrane phospholipids is an important stage in the process of histamine release. This methylation reaction can be modulated by S-adenosyl-methionine (SAM) as well as by S-adenosyl-homocysteine (SAH). The influence of SAM and of SAH upon the histamine release of leucocytes from asthmatic and normal subjects were compared. In concentration of 10(-4) M, SAM enhanced spontaneous and the specifically induced histamine release. In concentration of 10(-5) M SAM enhanced the histamine release only in normals. This phenomenon could indicate a deficit in methyl-transferase activity in the asthamatics. In concentration of 10(-4) M, SAH reduced spontaneous and specifically induced histamine release, having an effect comparable to that of 10(-4) M Theophylline.

A radioisotopic method for the determination of S-adenosyl-L-homocysteine in tissues in the 10(-7) M range

S-Adenosyl-L-homocysteine is able to bind to brain membranes. We used this characteristic to measure the level of S-adenosyl-L-homocysteine in rat brain tissue. The method is rapid, at the same time very sensitive (down to 10(-7) M) and specific.

Analysis of progesterone receptor in the quail oviduct. Correlation between plasmatic estradiol and cytoplasmic progesterone receptor concentrations

Specific binding sites for [3H]-progesterone are found in the cytosol fraction of the oviduct of castrated, immature and developing quails. The optimal conditions to accurately measure the total cytoplasmic concentration of this progesterone receptor are described. The dissociation constant (KD) at 0 degrees C is 3.6 +/- 0.6 x 10(-9) M (mean +/- SE) for [3H]-P and the concentration of binding sites is 13.4 +/- 2 pmol/mg DNA in immature animals. This binding capacity is not altered even 2 weeks after ovariectomy. During sexual development, although the dissociation constant remains unchanged, the number of binding sites increases to 74.5 +/- 1.6 pmol/mg DNA just before the beginning of the laying cycle. The concentration of cytoplasmic P receptor is under the inductive influence of estradiol. In castrated quails, estradiol 17 beta (E2) perfusion through the portal vein at a rate below or equal to 2 ng/min for 24 hr does not increase plasmatic E2 concentration and consequently does not change [3H]-P binding sites concentration in the oviduct. While E2 perfusion rate exceeds the metabolizing capacity of the liver (6.8 ng/min), both plasmatic E2 level and oviductal P receptor concentration are increased. When E2 is perfused through the jugular vein, plasmatic E2 level increases with the dose of E2 but P receptor concentration only increases when E2 perfusion rate reaches to 2.0 ng/min for 24 h.