Biomedical subjects
Publications and source records attributed to A Mai.
Thiomorpholine analogues of U-100480 with the biphenylmethyl group replacing the acetamidomethyloxazolidinone moiety have been synthesized and tested as antimycobacterial agents together with various related derivatives. Some biphenyl derivatives were endowed with high activity against Mycobacterium tuberculosis and other non-tuberculous mycobacteria.
Novel compounds related to 2-(cyclohexylthio)-3,4-dihydro-5-methyl-6-(3-methylbenzyl)-4-ox opyrimidine (3c, MC 639) have been synthesized and tested as inhibitors of human immunodeficiency virus type-1 (HIV-1). Reaction of thiourea with ethyl arylmethylacetoacetates furnished 5-alkyl-6-(arylmethyl)-3,4-dihydro-2-mercapto-4-oxopyrimidines which were then alkylated at the sulfur atom to afford the required 2-alkylthio or 2-cycloalkylthio derivatives (S-DABOs). Chemical modifications at N-3, C-4, and C-6 of the pyrimidine ring were attempted with the aim of improving antiretroviral activity. In particular, replacement of the benzyl group with the 1-naphthylmethyl moiety enhanced the activity of S-DABOs, whereas N-3 alkylation and C=O transformation into C=S at position 4 of the pyrimidine ring led to compounds devoid of anti-HIV-1 activity. Lower activity was generally observed when 1-naphthylmethyl was replaced by the isomeric 2-naphthylmethyl moiety. The most active compounds showed activity in the low micromolar range with EC50 values comparable to that of nevirapine.
Abundance of anophelines in 10 villages in the Wosera area of Papua New Guinea was monitored during 1990-1993. Of 85,197 anophelines collected in 1,276 paired indoor and outdoor landing catches, 40.4% were Anopheles koliensis Owen, 36.7% An. punctulatus Donitz, 14.3% An. karwari (James), 4.9% An. farauti s.l. Laveran, 3.1%, An, longirostris Brug, and 0.7% An. bancroftii Giles. Maps of average indoor biting rates were produced using a Bayesian conditional autoregressive model which allowed for heterogeneities in sampling effort over time and space. Differences in spatial distributions among species were observed among and within villages and were related to the distribution of larval habitats and vegetation. Abundance of An. punctulatus and An. koliensis decreased with distance from the main waterway and probably from a sago swamp forest at 6 villages in North Wosera. Abundance of An. punctulatus was associated negatively with those of An. farauti s.l., An. longirostris, and An. bancroftii. The latter 3 species also had relatively low ratios of indoor-to-outdoor biting rates, and earlier biting times than An. punctulatus. Human blood indices of at least 0.79 were observed for all species except An. bancroftii. Abundance of all 6 species was correlated temporally with recent rainfall, but An. koliensis, An. karwari, and An. longirostris showed greater temporal variability than the other species. An punctulatus and An. koliensis tended to occur together in time and space (index of association, I = 0.85). Weaker associations were seen between An. farauti s.l. and An. longirostris (I = 0.44) and An. koliensis and An. karwari (I = 0.34). The most frequently collected species occurred together and were concentrated near the Amugu river; the remaining species tended to occur together but in different parts of the Wosera area. The importance of understanding ecological requirements of the different Anopheles vectors and their association with key household and landscape features are discussed in relation to malaria transmission and control.
S1 proteins A-D are hnRNP proteins which were originally isolated from nuclei of various tissues, by selective extraction of pH 4.9 from the supernatants of nuclei mildly treated with DNase I or RNase A. In the present study, a hybridoma was isolated which produced a monoclonal antibody that reacted specifically with S1 proteins C2 and D2. When the antibody was used in indirect immunofluorescence staining of cultured cells, it stained, in addition to the nuclei, the cytoskeleton-like fibrous structures in the cytoplasm. We demonstrate that the cytoskeletal filaments are vimentin intermediate filaments. This is the first report on the hnRNP protein-association with cytoskeleton, and will help to clarify cytoplasmic mRNA localization as well as cytoplasmic distribution of hnRNP proteins.
OBJECTIVE: To illustrate blunt traumatic injury of the gallbladder in childhood. DESIGN: A case report. SETTING: Hospital. SUBJECT: An eight year old boy. MAIN OUTCOME MEASURE: Incidence, history, treatment. RESULT: The gallbladder was ruptured at the neck necessitating a cholecystectomy. The child has remained well at three months follow up. CONCLUSIONS: Blunt traumatic injury of the gallbladder, though rare, does occur usually as a consequence of direct abdominal injury especially in children during sporting activities and fights. Minor injuries can be repaired but cholecystectomy is necessary in more extensive injuries or injury to the cystic duct and neck. A comprehensive history taking including direct questioning regarding trauma and a high index of suspicion are important for early diagnosis and prompt treatment.
A 3-D QSAR study has been carried out on a new class of potent and selective human rhinovirus-14 (HRV-14) inhibitors. In particular, the CoMFA (comparative molecular field analysis) technique has been applied to develop a model able to explain and predict the anti-HRV-14 activity of a class of compounds 4 and potentially helpful to design new and more potent antirhinovirus agents. Docking experiments have also been performed with the aim of elucidating the possible binding mode of these inhibitors. These two approaches are combined to highlight a single, highly favoured mode of interaction of the compounds with the viral capsid proteins.
Using affinity chromatography on lactosyl-Sepharose, a beta-galactoside-binding protein of 38 kDa was detected in mouse L1210 lymphocytic leukemia cells. Immunoblotting analysis revealed that it is distinct from any known larger molecular weight galectin. The partial amino acid sequences of the 38 kDa protein indicated that it is a novel member of the galectin family. This 38 kDa lectin is expressed in lymphocytic cell lines but not macrophage-like cell lines.
OBJECTIVE: There are few and incomplete data about the epidemiology of echinococcosis in Germany. The aim of this retrospective study was to collect informations about frequency and distribution of this parasitosis in one of the main endemic regions (Bavaria). PATIENTS AND METHODS: Standardized questionnaires were sent to all Bavarian hospitals, requesting (anonymous) information about all patients with echinococcosis seen between 1985 and 1989. In addition, hospital statistics and archives were searched for echinococcosis cases. A total of 216 cases were found; sufficient data were available for 181 (87 males, 94 females; mean age 41 [4-79] years). There were 123 patients with cystic echinococcosis (infection with the larval stage of Echinococcus granulosus), 58 with the alveolar form (larval stage of Echinococcus multilocularis). In the remaining 35 the available information was inadequate for reliable differentiation. RESULTS: The data indicate a prevalence of echinococcosis in Bavaria of 1.9 per 100,000 inhabitants, 1.1 for Echinococcus granulosus and 0.5 for Echinococcus multilocularis. The mean annual incidence was 0.22 (Echinococcus granulosus 0.15; Echinococcus multilocularis 0.03). Dividing the patients by country of origin, 86.2% of those with Echinococcus multilocularis were German, while 68.3% of those with Echinococcus granulosus originated from outside Germany, mostly the Mediterranean area. The prevalence of Echinococcus multilocularis infection was highest in the District of Swabia (2.4/100,000) and Upper Bavaria (0.6/100,000). These are regions in which there is a proven significantly higher infestation of echinococcosis in foxes. Farmers were most at risk of being infected with alveolar echinococcosis.
Various thio analogues of dihydroalkoxybenzyloxopyrimidines (DABOs), a new class of non-nucleoside reverse transcriptase inhibitors, were found to selectively inhibit the HIV-1 multiplication in vitro. Among the C-5 H-substituted 6-benzyl-3,4-dihydro-4-oxopyrimidines, the introduction of alkylthio or cycloalkylthio substituents at C-2 of the pyrimidine ring led to derivatives (S-DABOs) which were up to 10-fold more potent than the alkyloxy or cycloalkyloxy counterparts. The further introduction of a methyl group at the 3'-position of the benzyl portion of 2-(alkylthio)-6-benzyluracils reduced the cytotoxicity leading to more selective compounds. Among C-5 methyl-substituted S-DABOs, numerous derivatives showed EC50 values as low as 0.6 microM and lacked cytotoxicity at doses as high as 300 microM. In the C-5 double methyl-substituted series, a more pronounced cytotoxicity was observed and the further introduction of a methyl at the 3'-position in the benzylidene group resulted in total loss of antiviral activity. S-DABOs, namely 2-(alkylthio)-6-benzyl-3,4-dihydro-4-oxopyrimidines, were synthesized by reacting proper methyl (phenylacetyl)acetates or their 2-methyl compounds with thiourea to afford 6-benzyl-4-oxo-1,2,3,4-tetrahydro-2-thiaoxopyrimidines or the related 5-methyl derivatives. Treatment of the latter derivatives with alkyl or cycloalkyl halides in alkaline medium gave the required title compounds.
As an approach to more extensive structural modifications of [(oxazolylphenoxy)alkyl]isoxazoles, we synthesized new compounds characterized by the replacement of the isoxazole nucleus with furan, pyrrole, and thiophene rings and by the presence of a ketocarbonyl group in the aliphatic chain connecting these pentatomic heterocycles to the 4-(4,5-dihydro-2-oxazolyl)phenoxy, 4-(ethoxycarbonyl)phenoxy, and 4-carboxyphenoxy moieties. Some pentamethylene derivatives were also prepared, and their antirhinovirus activity was compared to that of the corresponding ketomethylene derivatives. Syntheses were carried out by Friedel-Crafts acylation of the above pentatomic heterocycles and subsequent reaction of chloroalkyl ketones with the proper 4-substituted phenol. Reduction of the ketone function afforded the related polymethylene derivatives. The new compounds were tested for antirhinovirus activity and cytotoxicity in comparison with WIN 51711, used as reference drug. Inspection of the structure-activity relationships revealed that the thiophene ring and the carbonyl group are the structural components which to a large extent contribute to the positive biological profile in terms of both wideness of spectrum and low cytotoxicity. Among the various derivatives, compounds 8e,d showed in vitro the same potency of WIN 51711 but a cytotoxicity at least 10 times lower.
Novel 3,4-dihydro-6-benzyl-4-oxopyrimidines (DABOs), variously substituted at both the C-2 and C-5 positions of the pyrimidine ring, proved to be specific inhibitors of the human immunodeficiency virus type 1 (HIV-1) in vitro. Some compounds showed potency at micromolar doses, no cytotoxicity at the maximum testable doses and selectivity indexes comparable to that of 2'-3'-dideoxyinosine (ddI). Mode of action studies suggested that DABOs interfered with a step of the virus multiplication cycle following adsorption and preceding integration. Enzyme assays indicated that DABOs targeted HIV-1 reverse transcriptase: they inhibited the RNA-dependent DNA polymerase activity in a template-dependent manner and, to a lesser extent, the DNA-dependent DNA polymerase activity. No inhibition of the RNase-H associated activity was observed. When DABOs were assayed in combination with 3'-azido-3'-dideoxythymidine (AZT) or ddI against HIV-1 in cell cultures, a slightly synergistic inhibitory effect was observed. The combination of DABO 546 and AZTTP in enzyme assays showed that the two compounds were kinetically mutually exclusive.
The synthesis and antifungal activities of some dichlorophenyl-1H-pyrrol-2-yl-1H-imidazol-1-ylmethane derivatives substituted at pyrrole nitrogen are reported. When tested against Candida albicans and Candida spp., some derivatives were found to be from two to four times less active than miconazole, bifonazole and ketoconazole, used as standard controls.
The synthesis and antifungal activities of aryl-1H-pyrrol-2-yl-1H-imidazol-1-yl-methanes having allyl, crotyl, and acrylate chains linked to the N-pyrrole atom and substituted at phenyl ring by Cl, F, CH3, and NO2 groups are reported. In vitro tests against Candida albicans and Candida spp. showed 2,4-dichlorophenyl-1-allyl-1H-pyrrol-2-yl-1H-imidazol-1-yl-methane to be the most potent derivative with activities comparable to those of ketoconazole and slightly inferior to those of bifonazole and miconazole. Some structure-activity relationships are discussed.
The synthesis of some derivatives and analogues of 12,13,14,14a-tetrahydro-9H,11H-pyrazino-[2,1-c]pyrrolo[1,2- a][1,4]benzodiazepine (isonoraptazepine) is reported. The new derivatives have been subjected to pharmacological tests for evaluation of antidepressant effects. Neurobehavioral assays were also carried out to acquire data on neurotoxicity and sedative action. Isonoraptazepine analogues and derivatives lacked the pharmacological activity of mianserin and aptazepine and showed properties similar to imipramine. Molecular modeling studies revealed structural similarities between isonoraptazepine derivatives and imipramine, thus explaining the similar pharmacological profile found in some of the tests employed. Based on pharmacological data the title compounds cannot be regarded as alpha 2 presynaptic adrenoceptors antagonists. In vitro studies for receptor binding gave support to this observation. The above studies lead us to conclude that isonoraptazepine derivatives are conformationally restricted analogues of imipramine, but their antidepressant activity cannot be correlated to inhibition of 5HT uptake. Among the derivatives tested, 7b and 8e show some affinity for the d-fenfluramine receptor site, a serotonin presynaptic site connected with anorectic activity.
The synthesis of various pyrrylphenylethanones resembling cathinone and lefetamine is described starting from 2-chloro-1-(1-methyl-1H-pyrrol-2-yl)-2-phenylethan-1-one. Some derivatives showed good antinociceptic activity, comparable to that of morphine. The neuropsychopharmacological profile of title compounds has been also studied to explore their action on C.N.S.
A relationship exists between tumours and malformations both generally and in particular combinations. This is also valid for minor errors of morphogenesis suggesting that embryonic tumours are an expression of aberrant intra-uterine morphogenesis. We speculated that these minor aberrations might also manifest in other morphological defects, especially in minor anomalies and malformations of the ribs. We reviewed chest roentgenographs of 1000 children with malignancies for rib anomalies and compared them to 200 patients with mainly infectious diseases. We found 242 rib anomalies in 218 children with tumours (21.8%) and 11 (5.5%) in children without malignancy. This difference was statistically highly significant (P less than 0.001). A high incidence of cervical ribs was found in neuroblastoma (33%), brain tumour (27.4%), leukaemia (26.8%), soft tissue sarcoma (24.5%), Wilms tumour (23.5%) and Ewing sarcoma (17.1%). Only neuroblastoma showed a high incidence of rib bifurcation (4.5%). The increased incidence of these mesenchymal defects in children with malignancies may be another clue for an altered morphogenesis in tumour origin. In neuroblastoma the rib anomaly may be another expression of neurocristopathy as proposed for the association of congenital heart disease and neuroblastoma.
A number of aroylpyrroleacrylic acid derivatives were synthesized by standard procedures and evaluated for cytotoxicity in Vero cells and for capacity to inhibit the multiplication of viruses, bacteria, and fungi. While none of the test compounds showed any activity against bacteria and fungi, most of them inhibited the replication of some DNA viruses at concentrations allowing the exponential growth of uninfected cells. In particular three compounds (8, 9c, and 10h) showed an antiviral activity at doses that were from 4- to greater than 8-fold lower than the maximum nontoxic doses.
Some new 5,6-dihydro-4H-pyrrolo[1,2-a][1,4]benzodiazepine derivatives substituted at the 5 position have been synthesized and tested to evaluate their antidepressant and neuropsychopharmacological activities. The antinociceptic action of these compounds has been also assayed. The introduction of an ethoxycarbonyl group at the 4 position generally decreased the antidepressant effect.