Functional uncertainty, aging and memory processes during sleep

Disorganized sleep patterns, can be found both during normal development and in pathological conditions. Aging could also be accompanied by a disorganization of the night sleep episode; sleep could be interrupted by spontaneous awakening, sleep cycle could be shortened or incomplete, sleep states modified. These patterns suggest an inability to sustain a stable condition, i.e. a condition of functional uncertainty. Biological and cognitive implications of functional uncertainty conditions are discussed. In particular, the hypothesis has been put forward that disturbances of sleep could have a detrimental role on memory. Recent results obtained in our lab support this hypothesis: recall is correlated with NREM-REM cycles proportion. Future research should ascertain the role of the functional uncertainty with respect to the kind of memory being involved during sleep, and establish how much and for which cognitive processes (including those involved in dream production) the inability to sustain a steady condition impairs the functioning during sleep. The duration of the functional uncertainty condition is also important. The long-term study of the link between functional uncertainty and cognitive resources, could be important for the understanding of the night life and for an adequate treatment of patients.

Clinical subtypes of bipolar mixed states: validating a broader European definition in 143 cases

OBJECTIVE

To validate and clinically characterize mixed bipolar states derived from the concepts of Kraepelin and the Vienna School and defined as sustained instability of affective manifestations of opposite polarity--that usually fluctuate independently of one another--in the setting of marked emotional perplexity.

METHOD

Our criteria for mixed states represent a modified "user-friendly" operationalization of these classical concepts. We compared 143 mixed state patients, so defined, with 118 DSM III-R manic patients, systematically evaluated with the Semistructured Interview for Depression (SID) in our in-patient and day-hospital facilities.

RESULTS

The two groups were comparable from demographic and familial standpoints (including family history for bipolar disorder). Mixed states were predominant in the past history of index mixed patients who were more likely to have experienced stressors and to have attempted suicide; manic and hypomanic episodes were more common in the past history of the index manic patients who, in addition, had more episodes and hospitalizations. Although rates of chronicity and rapid cycling were not significantly different in the two groups, the modal episodes in the mixed states were 3-6 months, and in mania they were less than 3 months. Two thirds of both groups arose from a dysregulated baseline temperamental dysregulation, which in manics, was largely hyperthymic, and in mixed patients, was both hyperthymic and depressive. Of our 143 mixed states, only 54% met the DSM III-R criteria for mixed states (which conformed to "dysphoric mixed mania"); of the remaining, 17.5% could be described as "mixed agitated psychotic depressive states" with irritable mood and flight of ideas, and 26% as "unproductive-inhibited manic" with fatigue and indecisiveness. The family history and course of these "non-DSM III-R" mixed states were essentially similar to DSM III-R mixed states.

LIMITATION

Family history could not be obtained blind to clinical status in patients with severe psychotic mood states.

CLINICAL RELEVANCE

These data favor the classical European approach to mixed states over the grossly under-inclusive current official diagnostic systems.

CONCLUSION

The phenomenology of mixed states is more than the mere superposition of opposite affective symptoms and, in many instances, it represents an expansive-excited phase intruding into a depressive temperament, and a melancholic episode intruding into a hyperthymic temperament.

Accuracy of two newly described D-dimer tests in patients with suspected deep venous thrombosis

Accumulating evidence suggests that the ELISA determination of D-Dimer might be a useful tool for the exclusion of deep vein thrombosis (DVT) of lower extremities, because of its high sensitivity and negative predictive value. However, conventional ELISA assay is time-consuming and, therefore, is not suitable for emergency use. To evaluate the accuracy of two rapid assays recently described, 126 consecutive outpatients with the clinical suspicion of DVT underwent the NycoCard D-Dimer and the Instant I.A. D-Dimer determination, using venography as the reference test. In all patients, the conventional ELISA assay was also performed. Venography confirmed the presence of DVT in 30 patients (23.8%), and ruled out the diagnosis in the remaining 96. Instant I.A D-Dimer was positive in 28 patients with DVT (sensitivity, 93.3%), and negative in 90 subjects free from thrombosis (specificity, 93.8%). Nycocard D-Dimer correctly identified 27 patients with DVT (sensitivity 90.0%), and was negative in 77 subjects free from thrombosis (specificity, 80.2%). Sensitivity, specificity, negative and positive predictive values of both tests did not differ from those found with the classic ELISA method. In conclusion, both Instant I.A. D-Dimer and Nycocard D-Dimer assays show a great potential for clinical use.

Significance of the DNA synthesis in hypertrophic cardiomyopathies

DNA content and proliferating cell nuclear antigen (PCNA) expression were investigated in normal hearts, in hypertrophic from hemodynamic overload hearts and in hypertrophic cardiomyopathy (HCM). The aim of this study was mainly to determine whether the hyperdiploid myocardial cells in all cases are in dynamic or static phase. The percentage of PCNA positive cells only in the HCM group was significantly higher (mean value = 25.4%) than the percentage of hyperdiploid cells (mean value = 9.3%). Therefore, the DNA replication occurs through a different process from that of normal cell cycle which lead to an increase in ploidy and eventually mitosis. These data should be interpreted not only as the result of a periodic amitotic DNA renewal and not even as the result of an increased apoptosis, but especially as a repair process of the DNA molecules affected by a various types of damages in HCMs.

Nifedipine GITS versus diltiazem in chronic stable angina: a randomised multicentre study

In order to compare the efficacy of nifedipine gastrointestinal therapeutic system (GITS) with diltiazem, 99 patients with chronic stable angina were studied in a parallel-group randomised trial. According to the results of the two exercise tolerance tests (ETTs) performed during the placebo run-in, patients were divided into a fixed threshold group if the variability in time to 1 mm ST-segment depression was 20%, or a variable threshold group if it was higher. Efficacy was assessed by comparing the time to 1 mm ST-depression on a bicycle ETT after 4 weeks of treatment, adjusting for the baseline value. The adjusted means were 7.44 min for nifedipine GITS and 7.68 min for diltiazem; the difference was -0.24 min, with a lower 90% confidence limit of -0.90, which is within the stated interval for equivalence. The same result was confirmed by the 'intention-to-treat' analysis, and comparable results were obtained both in fixed and in variable threshold groups. The incidence of side effects was 12% with nifedipine GITS and 8.2% with diltiazem. Nifedipine GITS and diltiazem were found to be equally effective in increasing exercise tolerance in chronic stable angina patients.

Substituted indole-2-carboxylates as in vivo potent antagonists acting as the strychnine-insensitive glycine binding site

A series of indole-2-carboxylates bearing suitable chains at the C-3 position of the indole nucleus was synthesized and evaluated in terms of in vitro affinity using [3H]glycine binding assay and in vivo potency by inhibition of convulsions induced by N-methyl-D-aspartate (NMDA) in mice. 3-[2-[(Phenylamino)carbonyl]ethenyl]-4,6-dichloroindole-2-carboxyl ic acid (8) was an antagonist at the strychnine-insensitive glycine binding site (noncompetitive inhibition of the binding of [3H]TCP, pA2 = 8.1) displaying nanomolar affinity for the glycine binding site (pKi = 8.5), coupled with high glutamate receptor selectivity (> 1000-fold relative to the affinity at the NMDA, AMPA, and kainate binding sites). This indole derivative inhibited convulsions induced by NMDA in mice, when administered by both iv and po routes (ED50 = 0.06 and 6 mg/kg, respectively). The effect of the substituents on the terminal phenyl ring of the C-3 side chain was investigated. QSAR analysis suggested that the pKi value decreases with lipophilicity and steric bulk of substituents and increases with the electron donor resonance effect of the groups present in the para position of the terminal phenyl ring. According to these results the terminal phenyl ring of the C-3 side chain should lie in a nonhydrophobic pocket of limited size, refining the proposed pharmacophore model of the glycine binding site associated with the NMDA receptor.

Analysis of poly(ADP-ribose) glycohydrolase activity in nuclear extracts from mammalian cells

We have analysed poly(ADP-ribose) glycohydrolase, the enzyme responsible for in vivo degradation of ADP-ribose polymers, by means of a biochemical assay based on the capacity of the enzyme to use a synthetic 32P-labelled polymer as a substrate. The visualization of the reaction has been achieved by separation of poly and mono(ADP-ribose) by thin-layer chromatography followed by autoradiography, whereas polymer hydrolysis has been quantified by counting the spots corresponding to poly and mono(ADP-ribose). By addition of the enzyme inhibitor ethacridine to the reaction mixture, we have confirmed the specificity of the procedure we have developed. The protocol has been applied to study the specific activity of glycohydrolase in nuclear extracts from different mammalian cell lines and to an apoptotic experimental system, namely HL60 cells treated with etoposide. We have observed the activation of the enzyme after a two-hour drug treatment, that is concomitant with the activation of poly(ADP-ribose) polymerase, the enzyme which synthesizes the polymer. These data suggest a precise regulation of ADP-ribosylation process during cell death by apoptosis.

Postischemic hyperemia in subjects with lower limbs obstructive arteriopathy: role of PGI2 and endothelin

The physiological basis of postischemic hyperemia is not yet fully understood. The present study investigated the effects of pharmacologic manipulation of the prostaglandin system on local hemodynamics. Strain-gauge plethysmography was used to study 8 normal subjects and 9 patients with obliterating arterial disease of the lower limbs. Hemodynamic evaluations were performed before treatment, after seven days of low-dose acetylsalicylic acid (100 mg/day) to inhibit platelet thromboxane synthesis, and after acute infusion of 1 g of acetylsalicylic acid to inhibit endothelial prostacyclin synthesis. In patients with arterial disease, the hemodynamic study was also carried out after infusion of iloprost, a synthetic prostacyclin analogue. Acute infusion of acetylsalicylic acid significantly reduced basal blood flow in normal subjects, but not in patients with arterial disease. In the latter group, iloprost affected neither basal nor maximal postischemic flow. The study also evaluated the role of endothelin in musculocutaneous hemodynamic regulation, both in physiological conditions and in atherosclerosis. This part of the study addressed the possibility that the hemodynamic effects of vasodilator prostanoids like prostacyclin might affect endothelin release in vivo. During reactive hyperemia, plasma endothelin was reduced in normal subjects (-1.02 pg/mL, 95% CI: -2.23, 0.08), but not in patients with atherosclerosis (-0.35 pg/mL, 95% CI: -1.45, 0.75). In both groups, plasma endothelin was not affected by aspirin. These findings confirm the role of prostacyclin in local hemodynamic regulation. In the normal subject, musculocutaneous blood flow seems to depend at least in part on the action of vasodilator prostanoids and endothelin. This is not the case in patients with arterial disease, in whom plasma endothelin does not seem to be affected by postischemic changes in blood flow. A possible explanation for this difference could be alteration of the endothelial function in patients with arterial disease, related to the functional and structural characteristics of the artery wall in atherosclerosis.

Metal substrates influence the release of glycosaminoglycan and transforming growth factor beta by human bone cells

Bone cells derived from human jaw were isolated from explants and grown in vitro. Subcultures were cultured on plastic (control) and metal substrates for 24 and 48 hours in medium containing 3H-glucosamine and labeled glycosaminoglycan (GAG) accumulation was measured. In bone cells cultured on metal substrates there was an evident reduction in the synthesis and secretion of radiolabeled macromolecules compared to bone cells cultured on plastic. Moreover, the accumulation of single GAG classes was specific for each substrate tested. The results showed that titanium was the only metal substrate studied in which the percentage of individual GAG classes remained the same as control cultures. GAG reduction was due to a decreased synthesis and not to an increased degradation as shown by the decrement of exoglycosidase activity. The metals also reduced the activity of transforming growth factor beta (TGF beta), measured using interleukin-1 assay method, a factor involved in the various phases of bone remodeling; in this case, too, cells grown on titanium showed the highest TGF beta activity compared to the other metal substrates studied. The results indicate that the substrate to which the cells adhere do exhibit specific differences in GAG composition and TGF beta activity. The differences observed may be important during in vivo events such as guided tissue regeneration and bone deposition.

Environmental and human influence on the ecology of Trichinella spiralis and Trichinella britovi in Western Europe

Surveys on Trichinella parasites in domestic and sylvatic animals collected in France, Italy, and in the Extremadura region of Spain showed that the distribution of Trichinella spiralis and Trichinella britovi is influenced by both environmental and human behaviour factors. In France, both Trichinella species are prevalent in the fox population from mountain areas and natural parks but are infrequent in wild boars (< 0.001%). In Italy, only T. britovi is present in sylvatic animals (foxes, wolves, and mustelids) living 500 m above sea level. This species is rare in wild boars (< 0.001%) in that area. Sylvatic trichinellosis is found in only 24% and 34% of French and Italian territory, respectively, while lowland areas may generally be considered Trichinella-free, because the domestic cycle is absent. The ecology of T. spiralis and T. britovi in the Extremadura shows a different picture from that observed in France and Italy because of the presence of both domestic and sylvatic cycles. The domestic cycle not only allows the maintenance of T. spiralis in the domestic environment, but it also has a great impact on the prevalence in wild boar populations. It does not influence the prevalence in vulpine populations. These data suggest (1) that domestic trichinellosis occurs only in rural areas of Western Europe in association with traditional swine-rearing practices, but not in industrialized pig farms; (2) that sylvatic trichinellosis occurs only in natural habitats which, in Western Europe, are widespread in mountain areas; (3) that the fox is the primary reservoir in the sylvatic cycle, where the parasite is maintained in a closed circuit and (4) that among sylvatic animals T. spiralis is present at lower altitude than is T. britovi.

[Solitary fibrous mesothelioma of the peritoneum. Considerations of a clinical case in our observation]

The authors report a case of so-called solitary fibrous peritoneal mesothelioma which was successfully operated on. Their case is compared with the few cases reported in the literature. Analysis of findings shows the fibrous peritoneal mesothelioma to be a solitary well defined tumor, generally of considerable size at the time of the diagnosis, very similar to the fibrous metothelioma of the pleura. It is believed to originate in the sub-mesothelial connective tissue. Surgery provides a definitive cure.

[The expression of transforming and epidermal growth factors in organ cultures of embryonic lungs]

Bronchial branching of the early embryonic lung rudiments (Day 12 of pregnancy) cultivated on polycarbonic millipore TM filters was studied on the total preparations. Each lobe of the embryonic lung of the 12-day embryos has three to four terminal buds. After four days of cultivation, their number increased to 18. Immuno-reactive staining of EGF and its receptor was observed both in the cells lining the primitive airway and in the cells and extracellular matrix surrounding the airway of embryonic lung explants cultivated for four and 10 days on TM and MF filters. Expression of TGF-alpha was co-localized with that of EGF but on MF filters only. This mat be connected with the phenomenon of autoinduction.

[Hepatic resection in the fetal rabbit. Histologic comparison of tissue regeneration in the fetus versus the adult]

Fetal tissues present peculiar features of repair after injury. Although the development of fetal hepatocytes have already been studied in vitro and in transplant models, an in vivo study of fetal liver regeneration is still missed in the literature, to the best of our knowledge. Eight time-dated pregnant California rabbits (23, 24, 25, 30 days of gestational age) and 2 adult male California rabbits were anesthetized following a standardized i.v. protocol (ketamine 50 mg/kg; xilazine 5 mg/kg; propiopromazine 0.75 mg/kg; spontaneous breathing; no anesthetic gas). All the pregnant does underwent a midline laparotomy and a minimal hysterotomy to approach a fetus per each animal. In 2 cases, 1 fetus was delivered and prior to sacrifice the fetal liver was sampled in toto (30 days of gestational age). These pregnancies were allowed to continue to term and were uneventful with a full-term spontaneous delivery of the remaining fetuses. In the other 6 pregnancies, after the hysterotomy, the fetal abdomen was entered through a right-sided longitudinal incision and the liver was partially resected by thermocauterization. Fetal abdomen was closed in 1 layer (non absorbable suture 7-0). The fetus was then returned in the uterus and, after amniotic fluid restoration with warmed saline, the hysterotomy was sutured in double layer (polyglycolic 5-0). Maternal abdomen was closed in 1 layer (polyglycolic 4-0) and the skin in a continuous overlying fashion (silk 3-0). The abdominal cavity of the 2 adult male rabbits was entered through a right subcostal incision. Partial liver resection was performed, and abdominal and skin closure followed the same techniques used for the pregnant does. The treated livers were then sampled in toto at 24, 48, 72 hrs and 4 days after surgery from the fetuses, and at 7 days from the adult rabbits. Histological stains were: H & E; Van Gieson; Masson; Alcian Bleu; PAS. Fetal histology showed a low inflammatory reaction poor in PMN cells with minimal deposition of collagen and a high amount of glycogen in the hepatocytes. The inflammatory response to resection was much more evident in the adult samples as much as the abundant intra and extra-cellular deposition of collagen associated to a minor amount of intracellular glycogen. The peculiar features of liver regeneration in the fetus, deserve further experimental studies.

Encapsulation, metabolism and release of 2-fluoro-ara-AMP from human erythrocytes

2-Fluoro-ara-AMP (fludarabine phosphate) is a purine analogue with anti-neoplastic activity in lymphoproliferative malignancies. Fludarabine phosphate activity and toxicity is schedule-dependent; multiple daily administrations (for five days) are more effective than single dose. We have encapsulated fludarabine phosphate in human erythrocytes and found that it is slowly released as fludarabine for more than four days. Encapsulated fludarabine phosphate does not affect erythrocyte metabolism and is rapidly converted by erythrocyte enzymes both to fludarabine with a Km of 0.4 mM and a Vmax of 20 nmol/min per g hemoglobin and to fludarabine diphosphate and triphosphate. The apparent Km for fludarabine monophosphate in the phosphorylation reaction was 0.4 mM and the Vmax 40 nmol/min per g hemoglobin. In the phosphorylation of 2-fluoro-ara-AMP to the di- and triphosphate derivatives, ATP was the phosphate donor with apparent Km of 0.12 and 1.0 mM, respectively. During incubations of 2-fluoro-ara-AMP-loaded erythrocytes at 37 degrees C fludarabine was found in equilibrium between the erythrocyte and the culture medium suggesting that permeation of the erythrocyte membrane is not rate-limiting. Thus, fludarabine phosphate-loaded erythrocytes might be used as a slow-delivery system for fludarabine administration in the treatment of lymphoid malignancies.

[Secondary prevention of myocardial ischemia. From theory to clinical reality: preliminary results of the EUROASPIRE study in Italy. European Action on Secondary Prevention through Intervention to Reduce Events]

EUROASPIRE study has been carried out in 9 European countries with the aim of assessing coronary risk factors in high-risk patients admitted to hospital to undergo coronary revascularization procedures (coronary angioplasty or coronary artery bypass grafting) or because of angina or myocardial infarction. The results of the initial stage of the study in Italy, investigating the data from 691 hospital medical records, showed that management of risk factors in these patients was inferior than expected. In particular, the prevalence of hyperlipidaemia (63%), hypertension (40%) and diabetes (27%) was remarkably high. These results suggest that there is still a need for secondary prevention of coronary heart disease.

Inhibition of murine AIDS by reduced glutathione

The imbalance of the redox state in cells and body fluids in HIV-1-infected patients may result in progression of the disease as well as in immunologic disfuctions. In this report, we have evaluated whether the direct administration of high doses of reduced glutathione (GSH) exerts any antiviral activity and/or improves immune functions in a murine immunodeficiency animal model. Intramuscular administration of 50 or 100 mg GSH/mouse for five consecutive days weekly to LP-BM5-infected mice did not show local or systemic signs of acute toxicity. During the first 3 weeks from infection, a period in which clinical signs of disease were not yet detectable, GSH significantly reduced the viral load in lymph nodes and spleen as evaluated by a PCR semiquantitative assay of the proviral DNA content. At 10 weeks a GSH concentration-dependent reduction of splenomegaly, lymphadenopathy and hypergammaglobulinemia was evident in all treated mice. Evaluation of proviral DNA content showed that GSH was effective in inhibiting LP-BM5 infectivity in lymph nodes, spleen, and bone marrow at 100 mg/day, while it was less effective when administered at 50 mg/day. At 10 weeks some animals receiving the highest GSH dose died, thus only the mice receiving 50 mg GSH were followed up to 15 weeks without signs of toxicity. In this case, almost not significant differences among infected untreated or treated animals were observed. Thus, GSH is effective in reducing the proviral DNA load in the first period of infection. These data and the failure of sulfhydril supplementation to further counteract the progression of disease after 10 weeks of infection suggest that combinations of GSH and other antiviral agents may be useful for improving current antiviral therapies.

Age-related changes in the binding and uptake of Cu, Zn superoxide dismutase in rat liver cells

The present paper reports the effect of aging on receptor mediated endocytosis of Cu, Zn superoxide dismutase in rat liver cells. The fate of bovine Cu, Zn superoxide dismutase conjugated to colloidal gold was followed by electron microscopy in young (2 months) and old (24 months) rats in situ, in vivo and in vitro experiments. The use of different models for the study of the binding and internalization of the enzyme allowed to discriminate the contribution of each different liver cell type. The data obtained demonstrate that aging of the liver affects binding and uptake of this enzyme. In particular both the number of binding sites and the rate of internalization were depressed in old rats. Therefore, the hypothesis of therapeutic application of superoxide dismutase for age-related diseases needs to be revalued in view of the fact that receptor-mediated endocytosis of this protein is a mechanism affected by senescence.

[Ultrasonography in hypertrophic stenosis of the pylorus: clinico-therapeutic implications in borderline cases]

Previous publications attempted to define normal and abnormal ranges in the measurement of pyloric length (L), breadth (D), muscle thickness (S), volume (V) and muscle index (MI). We examined with US 286 patients with suspected hypertrophic pyloric stenosis and investigated all the above diagnostic criteria. Normal and abnormal ranges were in agreement in all five measurements, though less apparent for pyloric volume and muscle index. The patients with borderline values were 46 (16%) for pyloric muscle thickness, 98 (34%) for breadth, 52 (18%) for length, but only 22 (7.7%) for pyloric volume and muscle index. Borderline patients received medical therapy with the antispasmodic drug metaclopramide hydrochloride and they were examined with US after 15 days. Only 8 of 22 borderline patients (36%) developed a typical hypertrophic pyloric stenosis. In the others, pyloric volume was reduced and the symptoms subsided. Pyloric parameters cannot be always measured accurately, but pyloric volume and muscle index measures better distinguish normal from abnormal findings. The formula for pyloric volume calculation is simpler than that for pyloric muscle index calculation and easier to memorize, also because no correction for body weight is necessary.

Inhibition of murine AIDS by combination of AZT and dideoxycytidine 5'-triphosphate

SUMMARY

A combination of antiretroviral drugs acting on different cell types (lymphocytes and macrophages) was evaluated in a murine retrovirus-induced immunodeficiency model of AIDS (MAIDS). In a first experiment, C57BL/6 mice were infected with a single i.p. administration of LP-BM5 and treated with 0.125 or 0.25 mg/ml AZT in drinking water for 3 months. AZT treatment was found to reduce lymphadenopathy (60 and 65 percent, respectively), splenomegaly (37 and 50 percent, respectively), and hypergammaglobulinemia (6 and 50 percent, respectively). Furthermore, at the highest AZT concentration, BM5d proviral DNA content in lymph nodes and in the spleen showed a reduction of 78 and 70 percent, respectively, compared to untreated animals. In a second experiment, infected mice were treated with AZT (0.25 mg/ml in drinking water) and with 2',3'-dideoxycytidine 5'-triphosphate (ddCTP) encapsulated into autologous erythrocytes for macrophage protection. Combined treatments resulted in a further reduction of lymphadenopathy (a further 33 percent with respect to the single treatment of AZT) and splenomegaly (a further 28 percent respect to the single treatment of AZT) but not of gammaglobulinemia. Proviral DNA in lymph nodes and spleen showed a reduction of 82 and 77 percent, respectively, compared to infected mice. Stimulation index of T cells was also significantly increased in animals receiving both treatments versus AZT only. In conclusion, the selective administration of antiviral drugs that preferentially protect different cell types seems to provide additional advantages compared to single-agent therapy.

[Anatomo-clinical and epidemiologic study of Chagas disease]

Chagas' disease is a chronic form caused by a parasite, the Trypanosoma Cruzi, endemic of Latin America. The Trypanosoma Cruzi is transmitted by hematophageous bugs, particularly in dilapidated rural areas. Three phases of the disease can be distinguished: 1) acute phase, with high tissue and blood parasitic involvement; 2) undetermined phase, in which the diagnosis requires sophisticated clinical investigations; 3) chronic phase (10-30 years following the infection), characterized particularly by cardiac disease manifestations. The present 120 patients were subdivided into four groups: 1) 43 asymptomatic serum-positive subjects; 2) 25 serum-positive patients with electrocardiographic abnormalities; 3) 14 serum-positive patients with cardiomegaly; 4) 38 with classic chagasic cardiopathy. Comparative studies among these four groups were carried out employing Holter monitoring (24h), ergometric and phonomechanographic tests, M-mode and bidimensional echography and radionuclide ventriculography. A significant difference between the first 3 groups and, respectively, the fourth group (p < 0.001) was found. Deadly-risk (p < 0.001) manifestation were pointed out, such as a third tone, right bundle branch block with left anterior hemiblock and left ventricle's dilation. Autoptic controls were performed and in 4 patients the myocardial biopsy showed C3 and IgG deposition in capillaries and myocardial fibers, at electron microscopic examination, some thickening of capillary and myocytic basal membrane, interstitial collagen proliferation, besides non-specific myocellular abnormalities were detected.

Azidothymidine homodinucleotide-loaded erythrocytes and bioreactors for slow delivery of the antiretroviral drug azidothymidine

A new Azidothymidine derivative, di-(thymidine-3'- azido-2',3'-dideoxy-D-riboside)-5'-5'-p1-p2-pyrophosphate (AZTp2AZT), was encapsulated in human erythrocytes according to a conservative procedure of hypotonic shock-isotonic resealing and reannealing. Like in erythrocyte lysates supplemented with 1 mM ATP, intact red cells too were found to convert AZTp2AZT to 3'-Azido-3'-deoxythymidine which was then released linearly in plasma. The major metabolic pathway involved in this conversion was the symmetrical hydrolysis of AZTp2AZT to yield two 3'-Azido-3'- deoxythymidine-5'-phosphate molecules which were then dephosphorylated to 3'-Azido-3'-deoxythymidine. At late times of incubation, also a limited asymmetrical hydrolysis of AZTp2AZT became apparent in the intact erythrocytes, yielding 3'-Azido-3'-deoxythymidine-5'-diphosphate that was then converted to the triphosphorylated derivative. Therefore, erythrocytes loaded with AZTp2AZT act "in vitro" as bioreactors ensuring sustained and potentially useful release of 3'-Azido-3'-deoxythymidine.

N-[5-nitro-2-furfurylidene]-3-amino-2-oxazolidinone activation by the human intestinal cell line Caco-2 monitored through noninvasive electron spin resonance spectroscopy

The pathways participating in the metabolism of the nitrofuran antimicrobial drug N-[5-nitro-2-furfurylidene]-3-amino-2-oxazolidinone (furazolidone) in intact cells were investigated in the human intestinal cell line Caco-2. One-electron reduction of furazolidone led to the formation of a free radical intermediate that could be monitored in dense cell suspensions by noninvasive electron spin resonance spectroscopy. The effects of enzyme inhibitors on the kinetics of radical production and decay were used to estimate the relative contribution of different enzymes to the reductive activation of the drug. Although many enzymes are known to reduce nitrofurans in vitro (e.g., xanthine oxidase, aldehyde oxidase, DT-diaphorase, mitochondrial redox chain components), their contributions were insignificant in living Caco-2 cells. The first reducing equivalent required for the formation of the nitroanion derivative of furazolidone appeared to be provided essentially by the microsomal cytochrome P450 reductase. This was confirmed through studies of the NADPH-dependent radical formation by microsomes. Differentiated Caco-2 cells, an established enterocyte model, showed only modestly increased radical formation and the same enzyme-specificity pattern as undifferentiated cells. Consistently, only a small increase in P450 reductase activity was found in differentiated cells, in contrast to the 10-fold increase seen in typical differentiation marker enzymes. With the electron spin resonance method that we describe, it is possible to distinguish between sites of bioactivation of redox active drugs in intact cells.