The teriparatide in the treatment of severe senile osteoporosis

The osteoporosis is a systemic disease of multicausal etiopathogenesis. A progressive bone loss and qualitative alterations in the macro- and micro-architecture of the remaining bones, resulting in a loss of strength of bones to such an extent that even very modest traumas will cause fractures characterize it. Three forms are defined (i) postmenopausal appearing after the menopause, (ii) senile appearing with advancing age, and (iii) the idiopathic forms. Severe osteoporosis is declared when the patients suffer vertebral or femoral fractures without any trauma during a treatment with anti-reabsorptive medicines of at least 1-year. The treatment of osteoporosis is based on various categories of pharmaca, such as bisphosphonates, selective estrogen receptor modulators (SERMs), diaminobutyric acid (DABA), parathyroid hormone (PTH), estrogens and non-hormonal drugs. The teriparatide, the recombinant human (rh)PTH(1-34), is identical in amino acid sequence until the 34th (N-terminal) amino acid of the endogenous, human PTH. It is produced in E. coli using the recombinant DNA technology. It is a pharmacon having a strong trophic-anabolic action on the bone tissue, assuring both the inhibition of the bone loss, and the formation of new bones of good quality. It acts as a stimulant of the osteoblast functions, and at the same time, increases the absorption of calcium from the intestine, and also the renal reabsorption of calcium, and decreases the excretion of phosphates in the kidney. This study summarizes our own experience with the use of rhPTH(1-34) in the treatment of senile patients with severe osteoporosis. Our sample consisted of 40 elderly women of the mean age of 78+/-5 years, having severe osteoporosis. They displayed a columnar T-score>-3.5 and femoral T-score>-2.5, had been under antireabsorptive treatment since at least 12 months. In particular, 15 patients were treated with Alendronate (70 mg/week), 10 of them with Risedronate (35 mg/week), and 15 of them with Raloxifene (60 mg/day). These patients in our study were treated for 1 year with 20 microg/day of rhPTH (1-34), injected subcutaneously, and supplemented also with a daily dose of 1g of calcium and 800 IU of Vitamin D, per os. At start of this treatment (time t(0)), after 6 months (time t(6)) and after 12 months (time t(12)) patients underwent a bone mineral density (BMD) analysis (Dexa-Lunar-DPX-P) on the lumbar vertebral column, (L1-L4 zone), as well as a femoral BMD. We applied also quality of life (QoL) questionnaire of the European Foundation for Osteoporosis (QUALEFFO), and evaluated also the use of non-steroidal anti-inflammatory drugs (NSAIDs). Our final considerations are that the teriparatide therapy increases significantly the bone mass density, expressed in terms of T-Score, reduces the occurrence of new fractures, improves the QoL, and decreases also the consumption of NSAIDs.

The inflammatory abdominal aortic aneurysm and coronary artery disease. Case report and review

Inflammatory abdominal aortic aneurysm (IAAA) is defined as an unusually thickened aneurysmatic wall, encircled by a wide dense perianeurysmal and/or retroperitoneal fibrosis with adjacent tissues adhesion, and is now considered as an extreme shape of the common phlogistic process involved in atherosclerotic plaque formation. Latest studies demonstrated that inflammation plays an important role in coronary disease and in other atherosclerosis manifestations. We introduce the clinical case of a patient with IAAA who developed an acute myocardial infarction 6 months after the surgical procedure on the aorta. Through a literature review about IAAA we stress the clinical usefulness of the inflammatory markers as independent predictors in management of patients with coronary disease and we present the hypothesis, related to the introduced case, of an advanced coronary disease, aggravated or clinically revealed after the cytokine storm related to important localized inflammatory engagements or great vascular surgery treatments.

Proportional assist ventilation

Acute respiratory failure due to derangement of mechanical properties of respiratory system and/or to neuromuscular weakness has been defined as "poor neuroventilatory coupling.'' Proportional assist ventilation (PAV) is an innovative mode of partial ventilatory support designed to "amplify'' patient inspiratory effort and thus to restore a normal "neuroventilatory coupling.'' Potential advantages of PAV in terms of more physiologic patient-ventilator interactions have been evaluated by several studies. We review the literature to elucidate the state of the art of the clinical implementation of PAV.

Adaptive responses to the stress induced by hyperthermia or hydrogen peroxide in human fibroblasts

Perturbation of oxidant/antioxidant cellular balance, induced by cellular metabolism and by exogenous sources, causes deleterious effects to proteins, lipids, and nucleic acids, leading to a condition named "oxidative stress" that is involved in several diseases, such as cancer, ischemia-reperfusion injury, and neurodegenerative disorders. Among the exogenous agents, both H(2)O(2) and hyperthermia have been implicated in oxidative stress promotion linked with the activation of apoptotic or necrotic mechanisms of cell death. The goal of this work was to better understand the involvement of some stress-related proteins in adaptive responses mounted by human fibroblasts versus the oxidative stress differently induced by 42 degrees C hyperthermia or H(2)O(2.) The research was developed, switching off inducible nitric oxide synthase (iNOS) expression through antisense oligonucleotide transfection by studying the possible coregulation in the expression of HSP32 (also named HO-1), HSP70, and iNOS and their involvement in the induction of DNA damage. Several biochemical parameters, such as cell viability (MTT assay), cell membrane integrity (lactate dehydrogenase release), reactive oxygen species formation, glutathione levels, immunocytochemistry analysis of iNOS, HSP70, and HO-1 levels, genomic DNA fragmentation (HALO/COMET assay), and transmembrane mitochondrial potential (deltaPsi) were examined. Cells were collected immediately at the end of the stress-inducing treatment. The results, confirming the pleiotropic function of i-NOS, indicate that: (i). HO-1/HSP32, HSP70, and iNOS are finely tuned in their expression to contribute all together, in human fibroblasts, in ameliorating the resistance to oxidative stress damage; (ii). ROS exposure, at least in hyperthermia, in human fibroblasts contributes to growth arrest more than to apoptosis activation; and (iii). mitochondrial dysfunction, in presence of iNOS inhibition seems to be clearly involved in apoptotic cell death of human fibroblasts after H(2)O(2) treatment, but not after hyperthermia.

[Uterus in a male: persistent Mullerian duct syndrome. Report of a case with embryological considerations]

We describe a case of persistent mullerian duct syndrome incidentally found in a 79-year-old man. It was characterized by the presence of a uterus-like retroperitoneal mass composed of an ovoidal corpus and rudimental portio with a central lumen. Histologically the mass was leiomyomatous in nature, closely resembling myometrium, while the central lumen was lined by a monolayer of ciliated cuboidal to columnar epithelium similar to embryo-fetal celomatic epithelium. Although this is a dysembryogenetic syndrome due to the lack of regression of the mullerian duct, it may be incidentally discovered in elderly patients, as in the present case during hernioplastic surgery. We also briefly discuss the regression of mullerian duct, focusing on morphological features observed in a large collection of human embryos and fetuses, in order to better understand the pathogenesis of a "uterus' in a male without evidence of sexual abnormalities.

Chromatographic determination of 7,8-methylenedioxy-4H-2,3-benzodiazepin-4-ones in rat plasma: relationship to their anticonvulsant activity

The present investigation was designed to develop an assay suitable for pharmacokinetic studies of new compounds, i.e. the novel 7,8-methylenedioxy-4H-2,3-benzodiazepin-4-one derivatives (2a and 2b), acting as non-competitive AMPA-receptor antagonists. A reversed-phase high-performance liquid chromatographic method has been developed to determine the time-course of plasma concentrations of derivatives 2a and 2b administered intraperitoneally to Sprague-Dawley rats. The separation of compounds studied and a N-methyl-2,3-benzodiazepin-4-one derivative as internal standard (I.S.) from plasma, were carried out by liquid-liquid extraction using diethyl ether. The samples were injected onto the analytical column (Partisil 10 ODS) eluted with acetonitrile/0.01 M acetate buffer (pH 5.3) at a flow-rate of 2 ml/min and detected at 240 nm. Compounds 2a, 2b and I.S. gave retention times of 8.5, 5.25 and 11.1 min, respectively. The selectivity of the method was satisfactory. The mean recovery from spiked rat plasma ranged from 86.7 to 91.6% for 2a, and from 85.1 to 87.0% for 2b. The procedures were validated with a good reproducibility and linear response from 0.0625 to 2 microg/ml, with a regression coefficient of 0.9932 for 2a and 0.9854 for 2b. The lower limit of quantification (LOQ) was taken as 15 ng/ml for the two compounds. 2a and 2b showed no signs of significant degradation in rat plasma during storage at -20 degrees C and following freeze/thaw cycles. Moreover, plasma levels of the tested compounds have been correlated with their anticonvulsant activity, determined in vivo in genetically epilepsy-prone rats. Due to its sensitivity, the method was suitable for application to pharmacokinetic study.

[The glial cell in the ontogenesis of the human peripheral sympathetic nervous system and in neuroblastoma]

The developmental role of glial cells in the human peripheral sympathetic nervous system is still unclear. Immunohistochemical studies on human embryos and fetuses reveal that the migrating clusters of undifferentiated neuroblasts contain sustentacular cells and are completely separated from adjacent tissues by a peripheral layer of Schwann-like cells and continuous basement membrane. This topographic distribution seems to be strategic and suggests a role of glial cells and extracellular matrix in migration and differentiation processes of undifferentiated neuroblasts. A similar distribution pattern between glial cells/extracellular matrix and neuroblasts can be observed in neuroblastomas exhibiting a microscopic nodular growth pattern, providing additional evidence that neuroblastoma represents an arrest in the differentiation/maturation of cells during the ontogenesis of the human peripheral sympathetic nervous system. Although it is commonly believed that Schwann cells in neuroblastoma arise from cells "infiltrating neoplasia", arising from peripheral nerves adjacent tumor, our ontogenetic findings suggest that the glial cell component of neuroblastoma derives from that normally associated with developing neuroblasts. We discuss the normal development of the three lineages of the human peripheral sympathetic nervous system (ganglial, neuroendocrine or chromaffin, and glial), with special emphasis on glial cells and extracellular matrix components and on the comparison between ontogenesis and neuroblastoma.

Synthesis and structure-activity relationships of 2,3-benzodiazepines as AMPA receptor antagonists

There is increasing evidence of the potential therapeutic utility of glutamate receptor antagonists in the treatment of several neurodegenerative disorders, including stroke and epilepsy. In the last few years noncompetitive AMPA receptor antagonists have received considerable attention due to their therapeutic potentiality. The discovery of GYKI 52466, the prototype of noncompetitive AMPA receptor antagonists endowed with anticonvulsant and neuroprotective properties, induced growing interest on 2,3-benzodiazepine derivatives. This review covers the chemistry and pharmacology of this important class of AMPA receptor antagonists.

Proportional assist ventilation

Partial ventilatory support techniques are intended for patients who are unable to maintain a normal alveolar ventilation, despite normal central control for respiration. Proportional assist ventilation (PAV) is a novel mode of partial ventilatory support in which the ventilator generates an instantaneous inspiratory pressure in proportion to the instantaneous effort of the patient. In theory, PAV should normalize the neuro-ventilatory coupling by making the ventilator an extension of patient's respiratory muscles, while leaving to the patient the entire control of all aspects of breathing. PAV, however, shares a common problem with the conventional partial ventilatory support modes. In mechanically ventilated patients, the respiratory system impedance may change over time. These changes may impair the good matching between ventilator output and patient's ventilatory demand and lead to patient-ventilator asynchrony. To take full advantage of PAV, the authors believe that PAV should continuously and automatically adapt to the respiratory system passive mechanics, assessed by continuous noninvasive measurement of total elastance and resistance.

7-Chloro-1-(2,6-difluorophenyl)-1H,3H-thiazolo[3,4-a]benzimidazole and 1-(2,6-difluorophenyl)-6-methyl-1H,3H-thiazolo[3,4-a]benzimidazole

The title molecules, C(15)H(9)ClF(2)N(2)S and C(16)H(12)F(2)N(2)S, respectively, display the well known butterfly-like conformation with a flat thiazolobenzimidazole system. In both compounds, the mean plane through the tricyclic system is almost perpendicular to the 2,6-difluorophenyl ring. This arrangement of the aryl group is determined by two intramolecular hydrogen bonds and by an attractive F.S interaction.

Comparative immunohistochemical analysis of the expression of cytokeratins, vimentin and alpha-smooth muscle actin in human foetal mesonephros and metanephros

The human mesonephros is currently regarded as a simplified version of the foetal metanephros, primarily due to the close morphological resemblance between these two structures. The aim of the present study was to define whether human mesonephric and foetal metanephric nephrons share immunophenotypical traits in their corresponding structures (glomeruli, proximal and distal tubules). For this purpose we first investigated immunohistochemically the overall expression and topographical distribution of cytokeratins 7, 8, 18, 19, and 20, vimentin and alpha-smooth muscle actin in mature mesonephric nephrons and compared the results with those obtained in maturing-stage foetal metanephric nephrons. No expression of cytokeratins 7 and 20 was found. Cytokeratins 8, 18, and 19 and vimentin showed a restricted and basically coincident expression along the different components of both mesonephric and metanephric nephrons. These findings indicate that the intermediate filament protein profile of human mature mesonephric nephrons closely recapitulates that observed in developing metanephros and thereby strengthens the concept that human mesonephros, a transient ontogenic structure, is largely similar to the foetal metanephros. The sole difference between human mesonephros and foetal metanephros was the divergent expression of alpha-smooth muscle actin. This protein exhibited an increasingly accentuated mesangial expression paralleling the morphological maturation of metanephric glomerulus, whereas it was absent from the mesonephric one. This would suggest that the mesangial cells in these two renal structures have a different function during the foetal life.

Synthesis and anticonvulsant activity of novel and potent 1-aryl-7,8-methylenedioxy-1,2,3,5-tetrahydro-4H-2,3-benzodiazepin-4-ones

The synthesis and anticonvulsant activity of 1-aryl-7,8-methylenedioxy-1,2,3,5-tetrahydro-4H-2,3-benzodiazepin-4-(thi)ones (4a-d) and their 3-N-alkylcarbamoyl derivatives (4e-h) are reported. The new compounds possess marked anticonvulsant properties, comparable to those of the dehydro analogues 3 and higher than that of GYKI 52466 (1). Noteworthy, compound 4c shows a longer-lasting anticonvulsant activity. Electrophysiological experiments show that derivative 4c is less effective than 1 and 3c to reduce the KA-evoked currents in cerebellar granule neurons.

Synthesis and in vitro antitumour activity evaluation of 1-aryl-1H,3H-thiazolo[4,3-b]quinazolines

A series of 1H,3H-thiazolo[4,3-b]quinazolines (2a-i) were synthesized and evaluated for their in vitro antitumour activity against ca. 60 human tumour cell lines. They exhibited moderate (2c, 2d, 2f and 2g) to strong (2a, 2b, 2e, 2h and 2i) cell-growth inhibition at a concentration of 10(-4) M, but weak activity at lower concentrations. Only 1-(2,6-dichlorophenyl)-1H,3H-thiazolo[4,3-b]quinazoline (2h) possesses a significant growth inhibitory activity on 22 cell lines at a concentration of 10(-5) M.

Pressure-time curve predicts minimally injurious ventilatory strategy in an isolated rat lung model

BACKGROUND

We tested the hypothesis that the pressure-time (P-t) curve during constant flow ventilation can be used to set a noninjurious ventilatory strategy.

METHODS

In an isolated, nonperfused, lavaged model of acute lung injury, tidal volume and positive end-expiratory pressure were set to obtain: (1) a straight P-t curve (constant compliance, minimal stress); (2) a downward concavity in the P-t curve (increasing compliance, low volume stress); and (3) an upward concavity in the P-t curve (decreasing compliance, high volume stress). The P-t curve was fitted to: P = a. tb +c, where b describes the shape of the curve, b = 1 describes a straight P-t curve, b < 1 describes a downward concavity, and b > 1 describes an upward concavity. After 3 h, lungs were analyzed for histologic evidence of pulmonary damage and lavage concentration of inflammatory mediators. Ventilator-induced lung injury occurred when injury score and cytokine concentrations in the ventilated lungs were higher than those in 10 isolated lavaged rats kept statically inflated for 3 h with an airway pressure of 4 cm H2O.

RESULTS

The threshold value for coefficient b that discriminated best between lungs with and without histologic and inflammatory evidence of ventilator-induced lung injury (receiver-operating characteristic curve) ranged between 0.90-1.10. For such threshold values, the sensitivity of coefficient b to identify noninjurious ventilatory strategy was 1.00. A significant relation (P < 0.001) between values of coefficient b and injury score, interleukin-6, and macrophage inflammatory protein-2 was found.

CONCLUSIONS

The predictive power of coefficient b to predict noninjurious ventilatory strategy in a model of acute lung injury is high.

Neoadjuvant chemotherapy with ifosfamide, cisplatin, and vinorelbine in advanced squamous cell carcinoma of the cervix

A phase II trial was performed to assess the efficacy and toxicity of a combination of ifosfamide (IFX), cisplatin (CDDP), and vinorelbine (VNB) as neoadjuvant chemotherapy (NAC) for untreated advanced cervical carcinoma (ACC). Between October 1995 and February 1998, 40 patients were entered in this study. Their median age was 43 years (range: 23-74 years). International Federation of Gynecology and Obstetrics stages were: IIB, 23; IIIB, 13; and IVA, 4. Therapy consisted of: IFX 2,000 mg/m2 1-hour (H) IV infusion days 1 to 3; 2-mercaptoethanesulfonic acid sodium salt (mesna) 400 mg/m2 IV bolus H 0 and 4, and 800 mg/m2 by mouth H 8, days 1 to 3; VNB 25 mg/m2 20-minute IV infusion days 1 and 8; and CDDP 75 mg/m2 IV day 3. Cycles were repeated every 28 days for a total of three courses. Both staging and response (R) assessment were performed by a multidisciplinary team. An objective response (OR) was observed in 24 of 40 patients (60%; 95% confidence interval, 45-75%). Four patients achieved complete response (CR) (10%); 20 partial response (50%); 12 patients stable disease (30%); and 4 progressive disease (10%). Eight of 24 patients (33%) with OR underwent radical surgery, and histologic CRs were recorded in 2 of them. The remaining patients received definitive radiotherapy after NAC. The dose-limiting toxicity was myelosuppression. Leukopenia occurred in 32 patients (80%) and was grade III or IV in 14 patients (36%). Peripheral neuropathy occurred in 9 patients (22%), whereas myalgias occurred in 10 (25%). Constipation was observed in 9 patients (23%); emesis occurred in 35 patients (88%). There were no therapy-related deaths. These results indicate that IFX/CDDP/VNB is an active combination for ACC with moderate toxicity. Implementation of this regimen in a multimodal therapy protocol deserves further study.

Cathepsin D is a marker of ganglion cell differentiation in the developing and neoplastic human peripheral sympathetic nervous tissues

Cathepsin D (CD) is an aspartic proteinase which has been immunolocalised in intestinal ganglion cells of human neonates and adults. The aim of the present study was to define whether CD is a reliable ganglion cell differentiation marker in routinely fixed, paraffin-embedded tissues. For this purpose, we investigated immunohistochemically the expression and distribution of CD in the developing human peripheral sympathetic nervous system (PSNS) and gastroenteric nervous system (GENS), and in childhood neuroblastic tumours (NTs; neuroblastomas, ganglioneuroblastomas and ganglioneuromas), where ganglion cells differentiate from immature neuroblastic cells. During ontogenesis, CD expression is restricted to ganglion cell lineage with a progressively more intense cytoplasmic staining, mirroring the morphological differentiation of ganglion cells with increasing gestational ages. In neoplastic tissues, CD immunoreactivity was restricted to neuroblastic cells showing morphological features of gangliocytic differentiation (differentiating neuroblastomas, ganglioneuroblastomas) as well as to neoplastic ganglion cells (ganglioneuroblastomas, ganglioneuromas). We conclude that CD is a reliable ganglion cell differentiation marker, which can be used routinely to stain developing and mature ganglion cells in formalin-fixed, paraffin-embedded tissues. Furthermore, our results indicate that CD immunoreactivity in childhood NTs recapitulates the changes during normal PSNS development, as previously reported for Bcl-2 oncoprotein, c-ErbB2, insulin-like growth factor 2 and beta2-microglobulin. This is consistent with the current view that childhood NTs exhibit gene expression profiles mirroring those occurring during PSNS ontogenesis.

Synthesis and anticonvulsant activity of novel and potent 6,7-methylenedioxyphthalazin-1(2H)-ones

In this paper, we describe the synthesis of a series of novel substituted 4-aryl-6,7-methylenedioxyphthalazin-1(2H)-ones. The anticonvulsant activity of these compounds against audiogenic seizures was evaluated in DBA/2 mice after intraperitoneal (ip) injection. Most of these derivatives are more active than 1-(4-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2,3-benzodiazepine (1, GYKI 52466), a well-known noncompetitive AMPA receptor antagonist. As deduced by the rotarod test, all the compounds exhibit a toxicity lower than that of 1. Within the series of derivatives submitted to investigation, 4-(4-aminophenyl)-2-butylcarbamoyl-6,7-methylenedioxyphthalazin -1(2H)-one (21) proved to be the most active compound and is 11-fold more potent than 1 (i.e., ED50 3.25 micromol/kg for 21 versus ED50 35.8 micromol/kg for 1). When compared to 1, compound 21 as well as its analogue 4-(4-aminophenyl)-6,7-methylenedioxyphthalazin-1(2H)-one (16) show a longer lasting anticonvulsant activity. Compound 21 also effectively suppresses seizures induced in Swiss mice by maximal electroshock (MES) and pentylenetetrazole (PTZ). Furthermore, it antagonizes in vivo seizures induced by 2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA), 2-amino-3-(3-hydroxy-5-tert-butyl-isoxazol-4-yl)propionic acid (ATPA), and kainate (KA), and its anticonvulsant activity is reversed by pretreatment with aniracetam. Using the patch-clamp technique, the capability of derivatives 16 and 21 to antagonize KA-evoked currents in primary cultures of granule neurons was tested. They behaved as antagonists, but they proved to be less effective than 1 and 1-(4-aminophenyl)-3,4-dihydro-4-methyl-3-N-methylcarbamoyl-7,8-met hylenedioxy-5H-2,3-benzodiazepine (2, GYKI 53655) to reduce the KA-evoked currents.

First Report of Armillaria mellea on a Fern from Italy

Several perennial species of rhizomatous herbaceous ferns are cultivated as ornamental foliage plants. During late summer 1999, in a garden at the foot of Mount Etna, eastern Sicily (Italy), we noted a fern hedge showing patches of withered or stunted plants. The fern was identified as Cyrtomium falcatum (L.f.) C. Presl. (=Polystichum falcatum (L.f.) Diels), a house holly fern or Japanese holly fern, which is an ornamental fern native to East and South Asia. Other woody plants in the immediate vicinity had died over the last few years, including apricot and cedar trees whose stumps had not been removed. A close examination of uprooted ferns revealed the presence of creamy white fan-shaped mycelial mats with an odor typical of Armillaria species that were intermixed with the felt-like tangle formed by the rhizomes and roots of the ferns. In autumn, clumps of honey mushrooms with an annulus grew around patches of the withered fern hedge and in other parts of the same garden. The spore print of the basidiocarp was light cream. Basidiospores (8 to 9 × 5 to 6.5 µm) examined under a microscope were hyaline and apiculate. The fungus was isolated in pure culture from infected rhizomes with the selective medium of Kulman and Hendrix (3). In pure culture on 2% malt agar, the fungus formed ribbon-shaped, contorted, fast-growing rhizomorphs that branched profusely. Mycelial proteins of the isolate were analyzed by both polyacrylamide slab gel and starch gel electrophoreses, as described by Bragaloni et al. (1). The electrophoretic patterns of five isozymes (esterase, glutamic oxalacetic transaminase, phospho-glucomutase, alcohol dehydrogenase, and polygalacturonase) of the isolate from fern were identical to those of the reference isolate of A. mellea (Vahl:Fr.) Kumm. from grapevine. Conversely, the patterns were clearly distinct from those of reference isolates from other species, including A. ostoyae (Romagnesi) Herink, A. bulbosa (Barla) Kile et Watling, and A. cepistipes Velenovsky. Thus, on the basis of cultural, morphological, and biochemical characteristics, the species infecting the fern was identified as A. mellea. This pathogen, very common and widespread on wooded or previously wooded sites, has an extremely wide host range, encompassing both woody and herbaceous plants (2,4). However, this is the first report of A. mellea on a fern in Italy. References: (1) M. Bragaloni and N. Anselmi. Eur. J. For. Pathol. 27:147, 1997. (2) D. F. Farr et al. 1989. Fungi on Plants and Plants Products in the United States. The American Phytopathological Society, St. Paul, MN. (3) E. G. Kulman and F. F. Hendrix. Phytopathology 52:1310, 1962. (4) C. G. Shaw and G. A. Kile. 1991 Armillaria root disease. Agric. Handb. No 691. U.S. Department of Agriculture Forest Service, Washington, DC.

Sustentacular cells in sporadic paraganglioma-like medullary thyroid carcinoma: report of a case with diagnostic and histogenetic considerations

Sustentacular cells (SCs) are glial supporting cells of the fetal, adult normal, and neoplastic extra and adrenal human chromaffin cell lineage. SCs have also been identified in some cases of medullary thyroid carcinoma (MTC), raising both diagnostic and histogenetic problems. We report a rare case of a sporadic paraganglioma-like variant of MTC showing numerous S-100 protein and glial fibrillar acid protein (GFAP) positive SCs encircling neoplastic cells in a nesting (Zellballen) pattern similar to that observed in paragangliomas or pheochromocytomas. Although stromal amyloid deposits were only focally detected, diagnosis was immunohistochemically confirmed by immunoreactivity of the neoplastic cells for cytokeratin, CEA, calcitonin, chromogranin A, neuron-specific-enolase, and synapthopysin. As for the histogenesis of SCs, if we assume that MTC is a neural crest-derived tumor, it is likely that these cells reflect the ability of the common precursor cell to differentiate towards a sustentacular-type glial cell lineage in addition to the typical neuroendocrine one. This viewpoint is supported by the evidence that rare cases of MTC may contain neoplastic or supporting cells showing a multidirectional differentiation (usually neuroendocrine and melanocytic) that recapitulates the different cell lineages arising from the developing neural crests.

Compensation for increase in respiratory workload during mechanical ventilation. Pressure-support versus proportional-assist ventilation

Variation in respiratory impedance may occur in mechanically ventilated patients. During pressure-targeted ventilatory support, this may lead to patient-ventilator asynchrony. We assessed the hypothesis that during pressure-support ventilation (PSV), preservation of minute ventilation (V E) consequent to added mechanical loads would result in an increase in respiratory rate (RR) due to the large reduction in tidal volume (VT). WITH proportional-assist ventilation (PAV), preservation of V E would occur through the preservation of VT, with a smaller effect on RR. We anticipated that this compensatory strategy would result in greater patient comfort and a reduce work of breathing. An increase in respiratory impedance was obtained by chest and abdominal binding in 10 patients during weaning from mechanical ventilation. V E remained constant in both ventilatory modes after chest and abdominal compression. During PSV, this maintenance of VE was obtained through a 58 +/- 3% increase in RR that compensated for a 29 +/- 2% reduction in VT. The magnitudes of the reduction in VT (10 +/- 3%) and of the increase in RR (14 +/- 2%) were smaller (p < 0. 001) during PAV. During both PSV and PAV, chest and abdominal compression caused increases in both the pressure-time product (PTP) of the diaphragm per minute (142.9 +/- 26.9 cm H(2)O. s/min, PSV, and 117.6 +/- 16.4 cm H(2)O. s/min, PAV) and per liter (13.4 +/- 2.5 cm H(2)O. s/L, PSV, and 9.6 +/- 0.7 cm H(2)O. s/L, PAV). These increments were greater (p < 0.001) during PSV than during PAV. The capability of keeping VT and V E constant through increases in inspiratory effort after increases in mechanical loads is relatively preserved only during PAV. The ventilatory response to an added respiratory load during PSV required greater muscle effort than during PAV.

Dichotomic effects of IFN-gamma on the development of systemic lupus erythematosus-like syndrome in MRL-lpr / lpr mice

Systemic lupus erythematosus (SLE)-prone female MRL-lpr / lpr (MRL-lpr) mice were treated with mouse or rat IFN-gamma under different experimental conditions, both prophylactically in 6- to 8 week-old animals and therapeutically in 12- to 18-week-old SLE-affected mice. It was found that IFN-gamma heterogeneously modulated the course of the disease in MRL-lpr mice. When administered prophylactically, IFN-gamma favorably modulated the histological, serological and clinical signs of the disease. Relative to untreated or PBS-treated control animals, the MRL-lpr mice which received IFN gamma were virtually free of inflammatory infiltration of the kidneys and the lungs, had lower levels of azotemia with reduction of both circulating IgG1, IgG2a and IgG3 and anti-double strand (ds) and single strand (ss) DNA antibodies, milder skin vasculitis, significantly reduced enlargement of their lymph nodes and lower weight of the spleens. IFN-gamma also lowered the rate of mortality of MRL-lpr mice. In contrast to these findings, therapeutically administered IFN-gamma worsened the course of the disease in MRL-lpr mice, which exhibited increased proteinuria, higher levels of IgG2a and IgG3 and anti-ds and -ss DNA antibodies, more aggressive nephritis and died at an earlier age than PBS-treated control mice. The dichotomic effect of IFN-gamma on disease manifestation in MRL-lpr mice offers new insights into the complex role of this cytokine in the regulation of systemic autoimmunity such as SLE.

Synthesis and anticonvulsant activity of novel and potent 2,3-benzodiazepine AMPA/kainate receptor antagonists

We have previously shown that 1-aryl-3,5-dihydro-7, 8-methylenedioxy-4H-2,3-benzodiazepin-4-ones (3) possess marked anticonvulsant properties and antagonize seizures induced by 2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) in analogy to the structurally related 1-(4-aminophenyl)-4-methyl-7, 8-methylenedioxy-5H-2,3-benzodiazepine (1, GYKI 52466), a well-known noncompetitive AMPA/kainate receptor antagonist. We now report the synthesis of 3-(N-alkylcarbamoyl)-1-aryl-3,5-dihydro-7, 8-methylenedioxy-4H-2,3-benzodiazepin-4-ones (4a-h) and 1-aryl-3, 5-dihydro-7,8-methylenedioxy-4H-2,3-benzodiazepine-4-thiones (5a-c). The activity of all compounds, intraperitoneally (ip) injected, was evaluated against audiogenic seizures in DBA/2 mice and against seizures induced by maximal electroshock (MES) and pentylenetetrazole (PTZ) in Swiss mice. Some of the new compounds 4 and 5 showed remarkable anticonvulsant activity, and their toxicity, as evidenced by the rotarod test, is lower than that of 1. The time course of anticonvulsant activity of derivatives 4b and 5b,c was studied and compared to that of 1 and 3b,c. Compounds 4a,b and 5a-c antagonize seizures induced by AMPA and kainate (KA) and their anticonvulsant activity is reversed by pretreatment with aniracetam. Using the patch-clamp technique, the capability of derivatives 3c, 4b, and 5c to antagonize KA-evoked currents in primary cultures of granule neurons was tested and compared with that of the parent compounds 1 and 1-(4-aminophenyl)-3, 4-dihydro-4-methyl-3-methylcarbamoyl-7,8-methylenedioxy-5H-2, 3-benzodiazepine (2, GYKI 53655).

Time-course of impairment of respiratory mechanics after cardiac surgery and cardiopulmonary bypass

OBJECTIVE

Cardiopulmonary bypass (CPB) is associated with abnormalities of lung function characterized by an increase in static elastance of the respiratory system. We examined the following: a) the effects of CPB on the total inspiratory volume-pressure (V-P) relationship of the respiratory system; b) the relative contribution of the chest wall and lung to the impairment of respiratory system mechanics; and c) the time-course of such impairment.

DESIGN

Prospective, interventional study.

SETTING

Surgical and medical intensive care units in a teaching hospital.

PATIENTS

Eight adult patients scheduled for elective open heart surgery to correct valvular dysfunction.

INTERVENTIONS

V-P curves (interrupter technique) of the respiratory system were partitioned between the chest wall and lung by measurements of esophageal pressure. Measurements were obtained before sternotomy (control), immediately after, 4 hrs after, and 7 hrs after separation from CPB.

MEASUREMENTS AND MAIN RESULTS

Control V-P relationships of the respiratory system and lung showed lower inflection points (Pflex) at pressure values of 5.9+/-2.3 and 4.3+/-2.5 cm H2O, respectively. Immediately after and 4 hrs after separation from CPB, both curves had sigmoid shapes because of lower Pflex and formation of upper inflection (UIP) points. The pressures corresponding to the Pflex increased significantly (p < .001) by 56%+/-3% and 78%+/-4%, whereas the UIP corresponded to a pressure value of 42.34+/-8.5 and 35.6+/-7.8 cm H2O in the respiratory system and lung, respectively. A linear V-P relationship of the chest wall was observed during the control condition and after separation from CPB. Four hours later, no further increases in the pressure values corresponding to Pflex were observed on the inspiratory V-P curves of the respiratory system and lung, whereas the UIP occurred at a pressure of 35.6+/-9.1 and 29.7+/-8.4 cm H2O, respectively. A UIP was present on the V-P curve of the chest wall at a volume of 0.77+/-0.02 L. Seven hours after separation from CPB, the inspiratory V-P curves of the respiratory system, chest wall, and lung returned to normal.

CONCLUSIONS

Sternotomy and CPB produced immediate changes in lung mechanics. Chest wall mechanics were affected only 4 hrs after sternotomy. Seven hours after disconnection from CPB, all mechanics had returned to normal.

Endogenous interleukin-12 only plays a key pathogenetic role in non-obese diabetic mouse diabetes during the very early stages of the disease

A rat monoclonal antibody (mAb) that neutralizes mouse interleukin-12 (IL-12) was administered to female non-obese diabetic (NOD) mice of different ages to dismantle the role of endogenous IL-12 in murine autoimmune diabetogenesis. This mAb was effective in preventing clinical, but not histological signs of spontaneous diabetes when treatment was started early in life at the age of 4 weeks and consecutively continued for 10 weeks. Delaying commencement of anti-IL-12 mAb prophylaxis until the age of 18 weeks, when NOD mice suffer from advanced insulitis, was ineffective. Anti-IL-12 mAb did not influence the course of the accelerated model of diabetes induced by cyclophosphamide. These data prove that the pathogenetic role of endogenous IL-12 in NOD mouse diabetes is restricted to the very early diabetogenic events presumably occurring prior to insulitis development.

Synthesis and biological activity of novel 1H,3H-thiazolo[3,4-a]benzimidazoles: non-nucleoside human immunodeficiency virus type 1 reverse transcriptase inhibitors

Using a known human immunodeficiency virus type 1 (HIV-1) non-nucleoside reverse transcriptase inhibitor (NNRTI), 1-(2,6-difluorophenyl)-1H,3H-thiazolo[3,4-a]benzimidazole (TBZ NSC 625487) as the lead structure for drug design, a series of novel 1H,3H-thiazolo[3,4-a]benzimidazole derivatives substituted on the benzene-fused ring was prepared. Their in vitro anti-HIV-1 activity, as well as their inhibitory effects on the viral reverse transcriptase, were evaluated. The structure-activity relationships for these compounds are described and the results suggest that the apolar binding pocket of RT, into which the NNRTIs must fit, can accommodate only groups with a limited size and shape.

Internal electron transfer and structural dynamics of cd1 nitrite reductase revealed by laser CO photodissociation

Laser photolysis techniques have been employed to investigate the internal electron transfer (eT) reaction within Pseudomonas aeruginosa nitrite reductase (Pa-NiR). We have measured the (d1--> c) internal eT rate for the wild-type protein and a site-directed mutant (Pa-NiR H327A) which has a substitution in the d1-heme binding pocket; we found the rate of eT to be fast, keT = 2.5 x 10(4) and 3.5 x 10(4) s-1 for the wild-type and mutant Pa-NiR, respectively. We also investigated the photodissociation of CO from the fully reduced proteins and observed microsecond first-order relaxations; these imply that upon breakage of the Fe2+-CO bond, both Pa-NiR and Pa-NiR H327A populate a nonequilibrium state which decays to the ground state with a complex time course that may be described by two exponential processes (k1 = 3 x 10(4) s-1 and k2 = 0.25 x 10(4) s-1). These relaxations do not have a kinetic difference spectrum characteristic of CO recombination, and therefore we conclude that Pa-NiR undergoes structural rearrangements upon dissociation of CO. The bimolecular rate of CO rebinding is 5 times faster in Pa-NiR H327A than in the wild-type enzyme (1.1 x 10(5) M-1 s-1 compared to 2 x 10(4) M-1 s-1), indicating that this mutation in the active site alters the CO diffusion properties of the protein, probably reducing steric hindrance. CO rebinding to the wild-type mixed valence enzyme (c3+d12+) which is very slow (k = 0.25 s-1) is proposed to be rate-limited by the c --> d1 internal eT event, involving the oxidized d1-heme which has a structure characteristic of the fully oxidized and partially oxidized Pa-NiR.

Phase II of doxorubicin/taxol in metastatic breast cancer. Argentine Multicenter Taxol Group

PURPOSE

To assess the response rate, survival, and toxicity of Taxol (paclitaxel) as 1-h infusion plus doxorubicin as first-line treatment for patients with metastatic breast cancer (MBC).

PATIENTS AND METHODS

Seventy-six patients with untreated MBC were recruited. All of them had measurable disease and were evaluable for toxicity. Fifty-five percent of the patients had visceral involvement. The dose of doxorubicin was fixed at 50 mg/m2 as a short intravenous infusion, followed by 200 mg/m2 of Taxol as a 1-h intravenous infusion. Doxorubicin was administered during the first seven cycles, continuing with Taxol only up to a maximum of ten cycles.

RESULTS

Neutropenia was the most important toxicity: 30% grade 3 and 18% grade 4. Only 2 patients showed a decrease in the left ventricular ejection fraction (LVEF) which caused discontinuing the treatment. No clinical congestive heart failure (CHF) was observed. Seventy-four patients were eligible for response evaluation: 10 (14%) achieved complete response (CR) and 46 (62%) achieved partial response (PR). The mean duration of response was 13.47+/-1.35 months (95% confidence interval (CI): 10.82; 16.12) and the mean survival was 21.50+/-1.42 months (95% CI: 18.72; 24.29).

CONCLUSION

The overall response (OR) rate was 76%. No CHF was assessed and 2 patients stopped treatment due to LVEF decrease. Although doxorubicin 50 mg/m2 followed by Taxol 200 mg/m2 in 1-h intravenous infusion presents a toxicity profile which demands a close follow-up, it represents a convenient outpatient schedule with similar activity rate compared to longer Taxol infusions.

Synthesis and anticonvulsant activity of new 2,3-benzodiazepines as AMPA receptor antagonists

Novel 1-aryl-3,5-dihydro-7,8-methylenedioxy-4H-2,3-benzodiazepine-4-ones (12a-j) were prepared and their anticonvulsant effects were evaluated by using various models of experimental epilepsy. The seizures were evoked both by means of auditory stimulation in DBA/2 mice and by pentylenetetrazole or maximal electroshock in Swiss mice. Some of these compounds possess marked anticonvulsant properties in all tests employed. Compounds 12 antagonise seizures induced by AMPA in analogy to the structurally-related 1-(4'-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2,3- benzodiazepine (1) (GYKI 52466), a well-known non-competitive AMPA-receptor antagonist. On the other hand, these novel 2,3-benzodiazepines exhibit anticonvulsant properties that are not affected by flumazenil, but are reversed by aniracetam. In addition, when compared to model compound 1, compounds 12 show a longer-lasting anticonvulsant activity and a lower toxicity. A structure-activity relationship study carried out on compounds 12 as well as analogous 7,8-dimethoxy derivatives 2 offers an approach for designing more potent agents.

Vinorelbine and paclitaxel as first-line chemotherapy in metastatic breast cancer

PURPOSE

To evaluate the efficacy and toxicity of a combination of vinorelbine (VNB) and paclitaxel (PTX) as first-line chemotherapy in metastatic breast carcinoma (MBC).

PATIENTS AND METHODS

Between August 1995 and August 1997, 49 patients with untreated MBC received a regimen that consisted of VNB 30 mg/m2 in a 20-minute intravenous (IV) infusion on days 1 and 8 and PTX 135 mg/m2 in a 3-hour IV infusion (starting 1 hour after VNB) on day 1. Cycles were repeated every 28 days. The median age of the patients was 52 years, and 59% of patients were postmenopausal. Median performance status was 1. Dominant sites of disease were soft tissue in 6%, bone in 29%, and viscera in 65%.

RESULTS

Objective responses were recorded in 27 of 45 assessable patients (60%; 95% confidence interval, 46% to 74%). Complete remissions occurred in three patients (7%), and partial remissions occurred in 24 patients (53%). No change was recorded in 12 patients (27%), and progressive disease occurred in six patients (13%). The median time to treatment failure was 7 months, and median survival duration was 17 months. The limiting toxicity was myelosuppression, mainly leukopenia in 49 patients (100%) (grade 1 to grade 2, four patients; grade 3, 30 patients; and grade 4, 15 patients). Neutropenia was observed in 100% of patients (grade 1 to grade 2, three patients; grade 3, 11 patients; grade 4, 35 patients). Two treatment-related deaths due to febrile neutropenia were observed in patients with massive liver involvement. Peripheral neurotoxicity developed in 33 patients (67%) (grade 1, 25 patients; grade 2, eight patients); there were no grade 3 or grade 4 episodes.

CONCLUSION

The combination of VNB-PTX showed significant activity as first-line chemotherapy for patients with MBC. Myelosuppression was the dose-limiting side effect, whereas neurotoxicity was mild to moderate.

Synthesis, structure and in vitro anti-human immunodeficiency virus activity of novel 3-methyl-1H,3H-thiazolo[3,4-a]benzimidazoles

A series of novel 1-aryl-3-methyl-1H,3H-thiazolo[3,4-a]benzimidazoles, TBZ analogues, were synthesized and investigated as anti-human immunodeficiency virus (HIV) agents in order to study the effects of structural modifications on antiviral activity and cytotoxicity. They were proved to inhibit significantly HIV-1 replication in vitro without showing inhibitory activity on HIV-2 or simian immunodeficiency virus. Their potency was influenced by the presence of suitable substituents in the phenyl ring at C-1 as well as by their stereochemical characteristics. In fact, the most active compound of the series was the trans-1-(2,6-difluorophenyl)-3-methyl-1H,3H-thiazolo[3,4- a]benzimidazole, in which the butterfly-like conformation is stabilized by two intramolecular hydrogen bonds between the fluorine atoms and H-1 and H-3. This was made possible by the trans arrangement of C-1 and C-3 substituents, as shown by X-ray and NMR analysis.

7,8-Methylenedioxy-4H-2,3-benzodiazepin-4-ones as novel AMPA receptor antagonists

The synthesis and anticonvulsant activity of novel 7,8-methylenedioxy-4H-2,3-benzodiazepin-4-ones 3a-e, structurally-related to GYKI 52466 1, a well-known noncompetitive AMPA-receptor antagonist, are reported. The new compounds possess marked anticonvulsant properties and, in analogy to 1, antagonize seizures induced by AMPA. In addition, when compared to the model compound 1, compounds 3 show a longer-lasting anticonvulsant activity and a lower toxicity.

Prenatal diagnosis of cloacal anomaly

The authors present a case of prenatal diagnosis of cloacal anomaly, characterized by the presence of oligohydramnios and cystic pelvic mass with changing features during observation. Postnatal study confirmed the presence of a recto-cloacal fistula, with a high confluence of the urinary, genital and intestinal systems. Both parents had a chromosome 9 inversion (p11q13), but the child was chromosomally normal.

Paradoxical antidiabetogenic effect of gamma-interferon in DP-BB rats

Previous studies have shown that anti-gamma-interferon (IFN-gamma) antibody reduces the frequency of autoimmune IDDM in the DP-BB rat. We tested the effects of systemically administered recombinant rat IFN-gamma in both DP-BB and DR-BB rats. Unexpectedly, IFN-gamma markedly reduced the incidence of IDDM as compared with control rats when administered six times per week at a dosage of 280,000 U between ages 30-35 to 105 days or ages 60-64 to 105 days. A lower dosage (28,000 U on alternate days) was also protective when administered to DP-BB rats between birth and age 60 days. However, long-lasting protection against IDDM development over the 1-year study period was achieved only by the highest dosage of IFN-gamma administered from age 30 to 105 days. Ex vivo production of tumor necrosis factor-alpha from splenic lymphoid cells (SLCs) and peritoneal macrophages of the rats treated with IFN-gamma was comparable with that of controls; however, SLCs from the IFN-gamma-treated animals secreted lower amounts of IFN-gamma after stimulation with concanavalin A. IFN-gamma treatment also markedly reduced the frequency of phenotypically activated SLC-expressing class II antigens and interleukin-2 receptor. Finally, in agreement with the observed antidiabetogenic effects, exogenously administered IFN-gamma induced neither insulitis nor IDDM development in DR-BB rats, a subline of DP-BB rats in which autoimmune diabetes rarely occurs spontaneously but can be induced by administration of polyinosinic-polycytidilic acid.

Type VI collagen in glomeruli of short- and long-term experimental diabetic rats

Type VI collagen was revealed by high-resolution immunocytochemistry in renal glomeruli from short- and long-term streptozotocin-injected hyperglycaemic rats and from their age-matched normoglycaemic controls. The labellings obtained over the glomerular basement membrane and the mesangial matrix were assessed by quantitative evaluations. The labellings over the glomerular basement membrane were low and sparse in the young normoglycaemic animals but became consistent and increased in intensity with age and in both the short- and long-term diabetic animals. For the mesangial matrix, this was labelled more systematically, and its intensity increased with age and in the short-term hyperglycaemic animals. For the long-term hyperglycaemic animals, the intensities of labelling resembled those of their age-matched controls. These results indicate that type VI collagen appears to be a minor constituent of the extracellular matrix of the rat glomeruli, rather concentrated in the mesangial area in the young control animal. Concomitant with the general modifications of the extracellular matrix occurring with age and diabetes, this component increases, but apparently not with the length of the hyperglycaemic state.

Angiomyomatous hamartoma of the lymph node: case report with adipose tissue component

We report the first case of an angiomyomatous hamartoma of the inguinal lymph node with a significant adipose tissue component. The presence of a mixture of smooth muscle cells, blood vessels and adipose tissue, haphazardly arranged within a fibrous background, extending from the hilar region to the lymph node cortex, provides morphologic evidence of the hamartomatous nature of the lesion. We think that the term "angiomyolipomatous hamartoma" is more appropriate for such a lymph node lesion.

Protection from concanavalin A (Con A)-induced T cell-dependent hepatic lesions and modulation of cytokine release in mice by sodium fusidate

The immunomodulatory effects of the antibiotic sodium fusidate (SF) were tested in a model of T cell-dependent hepatic injury that can be induced in normal mice by a single i.v. injection of Con A. Signs of hepatitis with elevated transaminase activities in plasma, severe infiltration of the liver by neutrophil granulocytes, lymphocytes and monocytes, and necrotic areas were observed in control mice treated intraperitoneally with PBS 24 h and 1 h before Con A challenge. T cell- and macrophage-derived cytokines (IL-2, interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha, IL-1beta, IL-6) were released with different kinetics in the circulation of these mice. SF, 20, 40 or 80 mg/kg, administered 24 h and 1 h before Con A challenge, protected the mice against the hepatitic effects of Con A. The protective effects of SF were dose-dependent and accompanied by profound modifications of blood levels of cytokines induced by Con A, so that, relative to control mice, SF (80 mg/kg)-treated animals showed markedly diminished plasma levels of IL-2, IFN-gamma and TNF-alpha, along with augmented levels of IL-6. These results suggest that SF might be useful in the treatment of immunoinflammatory liver diseases in humans.

Liver is not the unique site of synthesis of beta 2-glycoprotein I (apolipoprotein H): evidence for an intestinal localization

Apolipoprotein H is a protein of about 50 kilodaltons, structurally related to the regulators of the complement activation family. Its physiological function is poorly understood but it has been implicated in lipid metabolism and coagulative pathways. The major site of synthesis is thought to be the liver. Several reports indicate that apolipoprotein H is the antigen of the antiphospholipid antibodies and also behaves as an acute-phase reactant. Moreover, 40% of plasma apolipoprotein H is associated with very low-density lipoprotein, high-density lipoprotein, and postprandial chylomicrons. In this study we investigated other sites of synthesis by reverse transcription/polymerase chain reaction and we found apolipoprotein H mRNA expression in intestinal cell lines and tissues. Immunohistochemistry was performed on various fresh and paraffin-embedded tissues and apolipoprotein H was immunolocalized in the cytoplasm of hepatocytes and epithelial cells from colon and jejunum. This study indicates that apolipoprotein H is expressed at both mRNA and protein levels in enterocytes.

Anti-HIV agents. V. Synthesis, structure and in vitro anti-HIV activity of novel 1H,3H-naphtho[2',3':4,5]imidazo[1,2-c]thiazoles

A series of 1H,3H-naphtho[2',3':4,5]imidazo[1,2-c]thiazoles, TBZ analogues, was prepared in order to explore the influence on anti-HIV activity of the spatial requirements of the hydrophobic moiety fused to imidazothiazole system. In spite of a butterfly-like conformation evidenced by X-ray analysis of compound 4g, the results of in vitro screening suggest that the replacement of the benzene fused ring by the naphthyl moiety negatively influences the activity of analogous thiazolobenzimidazole derivatives, some of which are potent non-nucleoside HIV-1 RT inhibitors.

Marine fungi in Terra Nova Bay (Ross Sea, Antarctica)

The occurrence of lignicolous marine fungi in Antarctic marine water far from the coast is reported. Thirty-six wooden baits (beech and poplar), hung in a metallic structure were immersed in Penguin Bay (Adelie Cove) at a depth of 50 m for a year. Fourteen species belonging to Deuteromycotina and six Ascomycotina were observed on the baits examined in Italy. Phoma sp., Trichocladium achrasporum, Trichocladium constrictum and Trichocladium lignincola were the predominant species. Phoma sp., the first species, are not typically marine, but rather of terrestrial origin. Penguin dung proximity can explain this occurrence.

Mutagenesis of nitrite reductase from Pseudomonas aeruginosa: tyrosine-10 in the c heme domain is not involved in catalysis

In Pseudomonas aeruginosa, conversion of nitrite to NO in dissimilatory denitrification is catalyzed by the enzyme nitrite reductase (NiR), a homodimer containing a covalently bound c heme and a d1 heme per subunit. We report the purification and characterization of the first single mutant of P. aeruginosa cd1 NiR in which Tyr10 has been replaced by Phe; this amino acid was chosen as a possibly important residue in the catalytic mechanism of this enzyme based on the proposal (Fulop, V., Moir, J.W.B., Ferguson, S.J. and Hajdu, J. (1995) Cell 81, 369-377) that the topologically homologous Tyr25 plays a crucial role in controlling the activity of the cd1 NiR from Thiosphaera pantotropha. Our results show that in P. aeruginosa NiR substitution of Tyr10 with Phe has no effect on the activity, optical spectroscopy and electron transfer kinetics of the enzyme, indicating that distal coordination of the Fe3+ of the d1 heme is provided by different side-chains in different species.

Convulsant effects of some xanthine derivatives in genetically epilepsy-prone rats

The behavioural and electrocorticographic (ECoG) convulsant effects of several xanthine derivatives injected intraperitoneally (i.p.) were studied in genetically-epilepsy prone rats. The aim of the study was to evaluate the relationship among convulsant potency, molecular structure and lipophilicity of some xanthines. Animals were injected i.p. with various doses (250-1000 micromol/kg) and a different convulsant potency was observed among the various xanthines tested. IBMX (3-isobutyl-1-methylxanthine), theophylline (1,3-dimethylxanthine) and caffeine (1,3,7-trimethylxanthine) induced an epileptogenic pattern that consisted in an initial phase characterized by wet-dog shakes followed by head tremor, nodding, clonic convulsion and they appeared to be the most potent xanthines among those studied. During seizures, the electrocortical activity was usually characterized by single or multiple sharp- or spike-wave episodes followed by polyspike discharges. After the highest doses of IBMX, theophylline and caffeine, the animals react with falling down, transient tonic clonic seizures, escape response and generalized seizures followed by post-ictal period. Equimolar doses of 8-chlorotheophylline and theobromine (3,7-dimethylxanthine) produced less evident epileptic responses in comparison to previous compounds, whereas no epileptic signs were observed following the administration of enprofylline (3-propylxanthine), etofylline [7-(2-hydroxyethyl)theophylline], diprophylline [7-(2,3-dihydroxy-propyl)theophylline] and doxofylline [7-(1,3-dioxolan-2-ylmethyl) theophylline]. Lipophylicity of the compounds was determined, but no convincing correlations were found between the rank order of lipophilicities and the convulsant potencies of the compounds studied. On the other hand, structure-activity relationship was also investigated. We suggest that the substitution pattern on the xanthine nucleus may explain, in part, the different convulsant potency of the compounds studied. Furthermore, a selective antagonism of adenosine subtype receptors should be considered.