Metabolism, mitochondrial uptake and toxicity of 2', 3'-dideoxycytidine

2',3'-Dideoxycytidine (ddCyd) is a prescription anti-retroviral drug that causes mitochondrial toxicity and peripheral neuropathy. ddCyd is actively phosphorylated by cytosolic deoxycytidine kinase and nucleoside (di)phosphate kinase to the 5'-triphosphate derivative. However, 2',3'-dideoxycytidine 5'-diphosphocholine (ddCDP-choline) was also found in human cells incubated with ddCyd. In this paper we show that ddCDP-choline is produced from dideoxyCTP (ddCTP) and phosphocholine by phosphocholine cytidylyltransferase. dCTP and CTP appear to activate this synthesis in a concentration-dependent manner. Although ddCTP and ddCDP-choline can both enter the mitochondria, ddCDP-choline uptake is more efficient than ddCTP uptake. These data suggest that ddCDP- choline is the ddCyd metabolite that is probably responsible for mitochondrial toxicity. The uptake of ddCTP and ddCDP-choline by mitochondria is inhibited by 3.0 mM l-carnitine in the cell-free system investigated; when added to U937 cells grown in the presence of 0.25 microM ddCyd, 3.0 mM l-carnitine partially abrogated the mitochondrial toxicity of ddCyd.

[Four species of mosquito as possible vectors for Dirofilaria immitis piedmont rice-fields]

Wild mosquitoes were allowed to feed, during two nights, on a heartworm-infected dog with a very high microfilaraemia (72,000 and 78,000 microfilariae/ml just prior to be allocated in the live trap). A heartworm-free dog was used as control bait in the second night. Engorged mosquitoes (Aedes caspius, Anopheles maculipennis s.l., Culex modestus, and Cx pipiens) were kept under laboratory conditions, artificially fed until day 10 post-infection (PI) and then dissected for the presence of Dirofilaria immitis larvae. Mortality of Ae. caspius and Cx modestus was significantly higher than controls on day 3 PI (89.4 and 80.3%, respectively), but survival rates were similar in the following period. Third-stage larvae were observed from day 12 to 17 PI in the four mosquito species studied. However, vector efficiency was significantly higher in Ae. caspius which produced 102 (73.9%) of the 138 infective larvae found. Although less efficient vectors, the other 3 species may contribute to D. immitis transmission in the study area due to their abundance (Cx modestus) or higher resistance to the negative effects of infection (An. maculipennis s.l., Cx pipiens). As far as Cx pipiens is concerned, this mosquito, which luckily fed the least frequently on the dog, confirmed to act as powerful vector in iperendemic areas. The risks for veterinary and medical health, related to the zoo-antropophylic host-feeding pattern of the studied species, are discussed.

Metabolism of furazolidone: alternative pathways and modes of toxicity in different cell lines

1. The metabolism and cytotoxicity of the antimicrobial nitrofuran drug furazolidone have been studied in Caco-2, HEp-2 and V79 cell lines. Free radical production, metabolite pattern, formation of bound residues, inhibition of cellular replication and protection by the antioxidant glutathione were compared for the three cell lines. 2. All three cell lines produced the same nitro-anion radical with similar kinetics. Little further metabolic breakdown was observed in V79 cells, whereas Caco-2 and HEp-2 cells showed extensive degradation of furazolidone, but with different end patterns. 3. Under hypoxic conditions, the colony-forming ability was extensively impaired in HEp-2 cells whereas the other two cell lines were less affected, suggesting that irreversible damage to DNA occurred prevalently in HEp-2 cells. In V79 cells the absence of oxygen caused a 25-fold increase in the formation of protein-bound residues. 4. Brief exposure to furazolidone caused a 50% loss of endogenous glutathione in Caco-2 cells, but no loss could be detected in V79 and HEp-2 cells. Consistently, when glutathione was depleted by buthionine-[S,R]-sulphoximine (BSO) and diethylmaleate (DEM) treatment, the viability of V79 and HEp-2 cells was minimally affected by furazolidone, whereas that of Caco-2 cells was substantially reduced. 5. It is concluded that the cytotoxicity of furazolidone in these cell lines can be exerted by a number of different mechanisms, possibly related to different metabolic pathways. The cytotoxicity of nitrofuran drugs, therefore, cannot be ascribed to a single toxic intermediate, but in Caco-2 cells furazolidone is extensively metabolized and detoxified by GSH, in V79 is only partially activated and then bound to proteins, whereas in HEp-2, once activated, may react with DNA.

Identification of Nematodirus species (Nematoda: Molineidae) from wild ruminants in Italy using ribosomal DNA markers

The sequence of the second internal transcribed spacer of ribosomal DNA was determined for four species of Nematodirus (Nematodirus rupicaprae, Nematodirus oiratianus, Nematodirus davtiani alpinus and Nematodirus europaeus) from roe deer or alpine chamois. The second internal transcribed spacer of the four species varied in length from 228 to 236 bp, and the G + C contents ranged from 41 to 44%. While no intraspecific sequence variation was detected among multiple samples representing three of the taxa, sequence differences of 5.9-9.7% were detected among the four species, Nematodirus davtiani alpinus and N. rupicaprae were genetically most similar (94.1%), followed by N. oiratianus, N. europaeus and N. rupicaprae (91.1-91.5%), whereas N. oiratianus was genetically most different from N. davtiani alpinus. The interspecific sequence differences were exploited for the delineation of the four species by PCR-based restriction fragment length polymorphism (using two enzymes) and single-strand conformation polymorphism. The results have implications for diagnosis, epidemiology and for studying the systematics of the Nematodirinae.

Leuconostoc species: a case-cluster hospital infection

Leuconostoc species are members of the Streptococcacae family. They are generally regarded as non-pathogenic culture contaminants and are thought to be an uncommon cause of infection. We present a study of a case-cluster nosocomial infection due to Leuconostoc spp. Three patients were hospitalized at the time of the infection with significant underlying diseases and all had a compromised skin and mucous barriers. Two had received previous antibiotic therapy. This report highlights the importance of Leuconostoc spp. as an emerging pathogen, even though the modes of transmission and reservoirs of Leuconostoc spp. are as yet unknown.

Histologic findings in the conduction system after cardiac transplantation and correlation with electrocardiographic findings

The study of the sinus node and the specialized atrioventricular junction by serial sections in cardiac transplantation revealed that acute rejection involving the conduction system was equally severe as the working myocardium, with the exception of the His bundle. During acute rejection, the sudden appearance of a first-degree atrioventricular block may suggest severe involvement of the conduction system with impending cardiac arrest.

Body fat distribution predicts the degree of endothelial dysfunction in uncomplicated obesity

OBJECTIVE

To ascertain in obesity the role of body fat distribution (the strongest predictor of morbility and mortality in obese subjects) in determining the degree of endothelial dysfunction, an early marker of atherosclerotic disease.

SUBJECTS

18 premenopausal women with uncomplicated obesity excluding other cardiovascular risk factors and 12 age-matched slim healthy women.

MEASUREMENTS

Endothelium-dependent vasodilation, studied as diameter variation in response to an increase in shear-stress, was evaluated in the right common femoral artery of obese and slim subjects by a non invasive approach and compared to glyceril-trinitrate vasodilation. To characterize better the vascular functional and/or structural properties, we studied the arterial wall distensibility by an echo-tracking system. Adipose tissue regional distribution was determined by computerised axial tomography.

RESULTS

The endothelium-dependent vasodilation was significantly impaired in obese subjects (P<0.005 versus non-obese subjects) while glyceril-trinitrate vasodilation and arterial distensibility were similar in the two groups. In our obese subjects endothelial-dependent vasodilation was inversely correlated to body fat distribution (visceral/subcutaneous adipose tissue ratio: r=- 0. 624, P=0.0058). In contrast, metabolic parameters (except C-peptide response during oral glucose tolerance test (OGTT): r=-0.587, P=0. 01), blood pressure values and body weight did not correlate with the endothelial function.

CONCLUSION

Uncomplicated obesity per se is characterised by an alteration of the endothelial function; the degree of this vascular damage is predicted by body fat distribution independently of body weight and metabolic and other haemodynamic parameters, and correlates with an index of insulin secretion.

Substituted indole-2-carboxylates as potent antagonists of the glycine binding site associated with the NMDA receptor

A novel series of indole-2-carboxylate analogues of GV150526 (1) in which the propenoic double bond was substituted with different "probes" or replaced by a isosteric cyclopropyl moiety were synthesized and evaluated for their affinity profile in order to obtain further information on the pharmacophoric model of the glycine binding site associated to the NMDA receptor.

[Health care inequalities: hospitalization and socioeconomic position in Rome]

Although the interest for equity is growing, scanty attention has been reserved so far in Italy to health care inequalities. The relation between hospitalization and socioeconomic position in Rome has been studied by evaluating overall heterogeneity and differences in access to effective non-discretionary treatments or at high degree of generic or specific inappropriateness. An area-based socioeconomic index was assigned to 86.4% out of 554.168 discharges of Rome residents identified during 1997 through the hospital information system. The analysis was performed by comparing standardized hospitalization rates across socioeconomic groups through linear trends and risk ratios. A significant inverse relation of overall hospitalization with socioeconomic position was observed for both acute admissions (+44% for most deprived males) and day hospital (+25%). No difference was found in use of effective treatments such as admissions in coronary care units for acute myocardical infarction or surgery for hip fractures. The inverse relation between socioeconomic position and acute hospitalization blunted in day hospital for inguinal hernia repair and actually reversed for cataract removal among females. The hospitalization risk for minor skin diseases, an ambulatory care sensitive condition, resulted inversely associated to socioeconomic position. An excess of hospitalization was also observed for poorest females undergoing appendectomy. Results indicate that observed heterogeneity between socioeconomic groups does not depend only on different health needs but also on an unequal utilization of services: although disadvantaged groups have equal access to treatments of non-discretionary effectiveness, they hardly use innovative services and are more vulnerable in receiving unnecessary treatments.

Proliferating cell nuclear antigen (PCNA) and apoptosis in hyperacute and acute myocardial infarction

The aim of this study was to determine whether cell proliferation and/or apoptotic cell death occur in hyperacute and acute infarction. Proliferating cell nuclear antigen (PCNA) and apoptosis were investigated in ten autoptic hearts within a few hours of infarction and in three normal hearts as controls. The PCNA Labeling Index (PCNA-LI) ranged from 0 to 3.1 in hyperacute infarction (mean 1.38), from 0.3 to 4 in acute infarction (mean 2.04) and from 0 to 1.2 in controls (mean 0.7). Although the results were not statistically significant, PCNA-LI was higher in acute than in hyperacute myocardial infarctions; and it was higher in hyperacute infarctions than in controls. Regarding apoptosis, the Apoptotic Index (AI) in hyperacute infarctions ranged from 0.7 to 3 (mean 1.78), in acute infarctions from 0.9 to 5 (mean 3.24) and in controls from 0 to 0.4 (mean 0.1). The AI was significantly higher in hyperacute and acute infarctions than in controls (p < 0.05).

Synthesis and biological application of a new heterodinucleotide with both anti-HSV and anti-HIV activity

A new antiviral drug with both anti-HSV and anti-HIV activity was synthesized by coupling Acyclovir and the acyclic nucleoside phosphonate (R)PMPA. The heterodinucleotide ACVpPMPA encapsulated into autologous erythrocytes was added to human macrophages providing an effective in vitro protection from HSV-1 and HIV-1 replication.

Anatomic study of the pelvis in carcinoma of the uterine cervix as related to the box technique

PURPOSE

To review the radiation therapy "box" technique for cancer of the cervix by means of magnetic resonance imaging (MRI), lymphangiography, and anatomic studies on cadavers.

METHODS AND MATERIALS

From 1993 to 1996, the anatomic borders of the "box" technique used at our Radiation Oncology Department-the superior border of the AP-PA fields at the inferior edge of L4; the inferior border at the inferior edge of the ischium; the lateral borders placed 2.5 cm outside of the bony pelvis rim; the anterior border of the lateral fields over the anterior edge of the pubic symphysis; and the posterior at the S2-S3 interspace-were reviewed in 35 sagittal MRI and 10 lymphangiographies of patients with FIGO IB (6), IIA (6), IIB (19), IIIB (3), and IVA (1). An anatomic revision was conducted on 30 cadavers to identify aortic bifurcation, lymphatic nodes, and uterus flexion.

RESULTS

In 50% of the patients with FIGO IB, the posterior border of the lateral field was inadequate to encompass the planning target volume (PTV), and in 67% with Stage IIA. In IIB, the anterior border was inadequate in 1 patient, and the posterior in 8 (42%). In IIB and IVA patients, the PTV was not encompassed. When correlating the anterior and posterior borders of the lateral field and the treatment volume in the 35 sagittal MRIs, the posterior border of the lateral field was inadequate in 49%, and the anterior border in 9% of the cases. According to the lymphangiography, the portals encompassed the external iliac nodes. Dissected female pelvises revealed that the aortic bifurcation occurred at the level of the inferior L4 edge in 80% of the cadavers. There was no correlation between uterus flexion in MRIs and in cadavers.

CONCLUSION

The design of the lateral fields of the four-field technique for the irradiation of the uterine cervix based on anatomic bone references failed to encompass the planning-target volume in a significant number of patients.

Import of DNA into mammalian nuclei by proteins originating from a plant pathogenic bacterium

Import of DNA into mammalian nuclei is generally inefficient. Therefore, one of the current challenges in human gene therapy is the development of efficient DNA delivery systems. Here we tested whether bacterial proteins could be used to target DNA to mammalian cells. Agrobacterium tumefaciens, a plant pathogen, efficiently transfers DNA as a nucleoprotein complex to plant cells. Agrobacterium-mediated T-DNA transfer to plant cells is the only known example for interkingdom DNA transfer and is widely used for plant transformation. Agrobacterium virulence proteins VirD2 and VirE2 perform important functions in this process. We reconstituted complexes consisting of the bacterial virulence proteins VirD2, VirE2, and single-stranded DNA (ssDNA) in vitro. These complexes were tested for import into HeLa cell nuclei. Import of ssDNA required both VirD2 and VirE2 proteins. A VirD2 mutant lacking its C-terminal nuclear localization signal was deficient in import of the ssDNA-protein complexes into nuclei. Import of VirD2-ssDNA-VirE2 complexes was fast and efficient, and was shown to depended on importin alpha, Ran, and an energy source. We report here that the bacterium-derived and plant-adapted protein-DNA complex, made in vitro, can be efficiently imported into mammalian nuclei following the classical importin-dependent nuclear import pathway. This demonstrates the potential of our approach to enhance gene transfer to animal cells.

Pathology of the heart and conduction system in a case of sudden death due to a cardiac fibroma in a 6-month-old child

A 6-month-old female infant considered to be in good health died suddenly and unexpectedly. Post-mortem examination was requested, with clinical diagnosis of sudden infant death syndrome. Gross examination revealed, however, the presence of a cardiac mass 4.5 X 4 x 3.5 cm in diameter. Histological examination of the heart confirmed the presence of a cardiac fibroma. In the present case, the sudden death could have been due to the left ventricular outflow obstruction, as much as to conductive disturbances caused by overstretching and compression of the atrioventricular node and of the bundle branches. Hemodynamic and conductive abnormalities are presumed to have provoked bradycardia degenerating into ventricular fibrillation and sudden death. Necroscopy studies of sudden death should always include histological examination of the cardiac conduction system but seldom do.

Heterodimer-loaded erythrocytes as bioreactors for slow delivery of the antiviral drug azidothymidine and the antimycobacterial drug ethambutol

Disseminated infection with Mycobacterium avium complex (MAC) remains the most common serious bacterial infection in patients with advanced AIDS. The organisms that make up this complex are found ubiquitously in the environment, yet rarely cause disseminated disease in nonimmunocompromised human patients; on the contrary, up to 50% of patients with AIDS may ultimately develop the pathology. Hence, therapeutic strategies able to inhibit HIV and Mycobacterium replication are needed. Because of the rapid plasma elimination and toxicity of the most commonly used drugs, daily multiple-drug therapies must often be continued throughout life, frequently causing major side effects and, as a consequence, poor patient compliance. Therefore, alternative strategies that reduce the toxicity of the drugs and allow prolonged application intervals are sorely needed. Since erythrocytes (RBCs) can behave as bioreactors able to convert impermeant prodrugs to membrane-releasable active drugs, new compounds (AZTpEMB, AZTpEMBpAZT, and AZTp2EMB) consisting of both an antiretroviral and an antimicrobial drug were designed and synthesized. Among these, only AZTp2EMB was hydrolyzed by erythrocyte enzymes and could be encapsulated inside RBCs. AZTp2EMB-loaded RBCs slowly released AZT and EMB in culture medium, reducing its concentration by one-half about every 48 hr of incubation at 37 degrees C. Moreover, when AZTp2EMB-loaded erythrocytes were incubated for 6 days in the presence of human macrophages infected with Mycobacterium avium (M. avium) a marked bactericidal effect (>1 log) was observed. Thus, AZTp2EMB-loaded erythrocytes could be used as endogenous bioreactors for AZT and EMB delivery in the treatment of HIV and M. avium infection.

Bulbo-spinal pathology in neurocardiac sudden death of adults: a pragmatic approach to a neglected problem

This paper gives an overview on the neurocardiopathy of reflexogenic sudden death in adults, focusing on the bulbo-spinal cardiovascular-respiratory centers and which is reminiscent of the recent findings in sudden infant death syndrome. The preeminent life-threatening derangements of the oxygen-conserving cardio-inhibitory reflex (dive-reflex and its subsets) were reconsidered in histopathology, together with bulbo-spinal sympathovagal abnormalities and possible underlying arrhythmogenic QT interval prolongation. A simplified methodology for the microscopical examination of the brain stem and upper thoracic spinal cord is suggested. The aim is to facilitate the pathologist's approach to a lamentably neglected, yet fundamental topic in the far-reaching domain of sudden cardiac death with no evidence of cardiovascular respiratory disease.

[Dynamics of ascitic fluid in decompensated cirrhosis]

The ascitic fluid in decompensated liver cirrhosis constitutes a continuously circulating pool which carries on sustained water exchanges with plasma and extracellular fluids through the whole peritoneal membrane. The actual ascites volume results therefore from the steady-state between the formation and reabsorption transperitoneal water flows. The ascitic reabsorption concerns both the "iso-osmotic" (i.e. the portion bound to the ascitic proteins and solutes) and the "free-water" (i.e. the amount exceeding the osmotic bounding ability of the peritoneal solutes) fractions of total ascitic water. By means of a simple dilution test, it is possible an in vivo estimation of both the ascites volume and the rate of transperitoneal free-water reabsorption, which is the actual free-water peritoneal clearance (CPAL) and an evaluation of the total intra-abdominal pressure (PIA). PIA results from the sum of the ascitic hydrostatic pressure, and the tension of the abdominal wall. Diuretic administration is able to significantly reduce CPAL, inducing a negative sodium balance and thus leading to a readjustment of ascites steady-state. This fact may cause reductions of ascites volume and PIA only after several days of diuretic treatment. An acute diuretic treatment by itself, even if intensive and resulting in a rapid diuresis and a significant modification of CPAL, does not appear able to determine rapid and detectable modifications of PIA. CPAL has an intrinsic prognostic value in patients with decompensated cirrhosis, since the cumulative mortality was reported to be significantly higher in the patients with lower CPAL levels. The peritoneal clearance ability may be regarded as a compensatory mechanisms of portal hypertension, and its estimate may be a reliable index of patient's aptitude to a lower hydro-retentive trend, which is in turn correlated to a greater cirrhosis severity and a worse prognosis.

Sudden and unexpected infant death due to an hemangioendothelioma located in the medulla oblongata

Herein, we report the case of a 4-month-old male infant dying suddenly and unexpectedly. Post mortem examination was requested with clinical diagnosis of Sudden Infant Death Syndrome (SIDS). Histological examination showed instead the presence of an hemangioendothelioma located in the medulla oblongata. Sudden unexpected death is the commonest form of death among babies between 1 month and 1 year of age. Although the vast majority of these fatalities are related to SIDS, a very small percentage is due to primary neoplasm. Necroscopy studies of sudden infant death should always include an accurate histological examination of the medulla oblongata on serial sections but seldom do.

Early laparoscopic cholecystectomy for acute cholecystitis: a safe procedure

Acute cholecystitis is increasingly managed by laparoscopic cholecystectomy. Some reports have shown conversion and complication rates that are increased in comparison to elective laparoscopic cholecystectomy. This study reviews the combined experience of two hospitals where the intention was to perform early laparoscopic cholecystectomy for acute cholecystitis. A total of 152 cases of laparoscopic cholecystectomy for acute cholecystitis (evidence of acute inflammation clinically and pathologically) were identified. Conversion to open cholecystectomy was required in 14 cases (9%) in the total series. Laparoscopic cholecystectomy was performed within 2 days of admission in 76% (115 of 152) of patients. Conversion was significantly less likely in patients undergoing laparoscopic cholecystectomy within 2 days of admission (4 of 115) compared to those undergoing surgery beyond 2 days (10 of 37; P<0.0001). Eleven patients (7%) had postoperative complications; however, there were no cases of injury to the biliary system and no perioperative deaths. This series shows that laparoscopic cholecystectomy can be performed safely in patients with acute cholecystitis and suggests that early laparoscopic cholecystectomy is preferable to delaying surgery. Although the conversion rate to open surgery is higher than for elective cholecystectomy, the majority of patients (91%) still derive the well-recognized benefits of laparoscopic cholecystectomy. Early laparoscopic cholecystectomy is an acceptable approach to acute cholecystitis for the experienced laparoscopic surgeon.

Chronic mania. Family history, prior course, clinical picture and social consequences

BACKGROUND

Mania with chronic course has been overlooked in the recent literature. Our aim was clinically to characterise and validate this form of mania.

METHOD

We evaluated 155 people with DSM-III-R mania and assessed their family history, temperament, symptomatology and course. We used a semi-structured interview for mood disorders, as well as the Comprehensive Psychopathological Rating Scale and the Scale for the Assessment of Positive Symptoms.

RESULTS

Twenty (13%) had a chronic course arising from a background of hyperthymic temperament and recurrent mania, with a deteriorative pattern. Clinically, they were characterised by a significantly high rate of almost constant euphoria, grandiose delusions and related delusions, but had relatively low rates of sleep disturbance, psychomotor agitation and hypersexuality.

CONCLUSION

Even with current therapies a significant number of people with bipolar disorders have a deteriorative outcome associated with the gradual disappearance of acute mania with an increase in megalomanic delusions, alienation from loved ones and decreased likelihood of medical and psychiatric care.

The effects of irbesartan added to hydrochlorothiazide for the treatment of hypertension in patients non-responsive to hydrochlorothiazide alone

AIM

To evaluate the antihypertensive efficacy and safety of adding irbesartan to hydrochloride (HCTZ) in patients not adequately controlled by HCTZ alone.

PATIENTS AND METHODS

In this multicenter study, after a single-blind, placebo lead-in period, hypertensive patients received single-blind HCTZ 25 mg once daily. After 4 weeks, 238 patients with seated diastolic blood pressure of 93-110 mmHg continued on HCTZ 25 mg once daily and were randomized to double-blind irbesartan 75 mg once daily or matching placebo for 12 weeks. At week 6, the dosage of irbesartan or placebo was doubled for seated diastolic blood pressure > or = 90 mmHg.

RESULTS

At weeks 2, 6, and 12, irbesartan/HCTZ resulted in significantly greater (P<0.01) reductions from baseline in trough seated diastolic and systolic blood pressure compared with placebo/HCTZ. At week 12, the mean reductions in trough seated diastolic and systolic blood pressure were 7.2 mmHg (95%, C.I., 5.1-9.3 mmHg) and 11.1 mmHg (95% C.I., 7.9-14.3 mmHg) greater, respectively, with irbesartan/HCTZ compared with placebo/HCTZ. At week 12, significantly (P < 0.01) more patients were normalized (trough seated diastolic blood pressure < 90 mmHg) with irbesartan/HCTZ (67%) compared with placebo/HCTZ (29%). The frequency of adverse events, serious adverse events, and discontinuations attributed to adverse events was similar in both groups, and there were no clinically relevant changes in serum creatinine, potassium, or any other laboratory parameter.

CONCLUSION

Irbesartan was effective and well tolerated when added to a background of HCTZ 25 mg in patients whose blood pressure was not adequately controlled by HCTZ alone.