Activity of trovafloxacin in combination with other drugs for treatment of acute murine toxoplasmosis

Current therapy for toxoplasmosis with a synergistic combination of pyrimethamine plus sulfadiazine or pyrimethamine plus clindamycin is not always efficacious and is frequently discontinued due to intolerable toxic effects in immunocompromised individuals, particularly those with AIDS. Trovafloxacin, a new fluoroquinolone with potent activity against Toxoplasma gondii, was examined for potential synergistic activity when combined with other drugs used for treatment of human toxoplasmosis. Combinations of trovafloxacin with clarithromycin, pyrimethamine, or sulfadiazine demonstrated significantly enhanced activities compared to those observed with each drug alone. Our results suggest that combinations of trovafloxacin and other anti-toxoplasma drugs should be further explored for treatment of toxoplasmosis in humans.

Development of gastroenterology in Bangladesh

Diseases of the gastrointestinal tract and liver are very common in Bangladesh. Gastroenterology as a dedicated specialty was initiated in 1977 at the Institute of Postgraduate Medicine and Research in Dhaka. One more centre was set up later and these centres are providing specialized diagnostic and therapeutic services. These centres are also imparting training in endoscopy and 49 endoscopists trained so far are providing services in 22 centres around the country. Clinical gastroenterologists are also being trained in a 3 year Master's degree course and three specialists have already completed this. A Gastroenterology Society was formed in 1988 and has held three national scientific conferences and 20 regional meetings. Research in special problems of the country has also been initiated and work on aspects of peptic ulcer disease, chronic calcific pancreatitis and chronic viral hepatitis has been conducted. The demand for gastrointestinal services is high and the specialty has attracted a good number of young doctors. Gastroenterology is likely to grow in size and quality in Bangladesh.

Rapid and sensitive method for the detection of Aeromonas caviae and Aeromonas trota by polymerase chain reaction

A 16S rDNA-based polymerase chain reaction (PCR) method was developed for the detection of Aeromonas caviae and Aeromonas trota. These two species were identified from other Aeromonas spp. and closely related species by primers set (AER1 and AER2). The amplified product was 316 bp. The identity of the amplified product was confirmed by DNA-DNA hybridization. Two sets of primers (AER8 and AER9) were used for specific identification of Aer. caviae. Amplifying the 260 bp fragment of 16S rRNA gene region and digesting it with AluI restriction enzyme, yielded 180- and 80-bp fragments. For PCR assay, template DNA was released by mixing equal volumes of homogenized seeded crab meat with Aer. caviae and Chelex 100 (6%) incubated for 10 min at 56 degrees C followed by addition of an equal volume of 0.1% Triton-X-100 and boiled for 10 min. The detection limit was between 50 and 100 cells g-1 of crab meat. This method is very rapid and obviates the need for DNA isolation from complex food matrices and is specific for detecting two Aeromonas species.

Pharmacokinetic studies of 13-cis-retinoic acid in pediatric patients with neuroblastoma following bone marrow transplantation

A phase I clinical trial of 13-cis-retinoic acid (cis-RA) was undertaken to determine the maximally tolerated dose (MTD) and pharmacokinetics (PK) of cis-RA following bone marrow transplantation (BMT) in children with high-risk neuroblastoma. Mean peak serum levels of cis-RA in 31 pediatric patients ranged from 4.9 to 8.9 microM following doses of 100-200 mg/m2 per day, divided into two doses every 12 h administered orally. The PK of cis-RA obeyed a single-compartment model following first-order absorption in the majority of patients. A linear increase in the mean peak serum levels and area under the time-concentration curve (AUC) with increasing dose was observed. The average half-lives of absorption and elimination were 1.0 and 5.8 h, respectively. At the MTD of 160 mg/m2 per day, the mean cis-RA peak serum concentration was 7.2 +/- 5.3 microM. AUC values were not altered significantly during a 2-week course of treatment or over a long period of multiple courses. Levels of trans-retinoic acid, a metabolite of cis-RA, remained low but were similar on days 1 and 14, whereas the 4-oxo-13-cis-RA metabolite had increased in 64% of patients by day 14. Peak serum cis-RA concentrations correlated with clinical toxicity as grade 3 to 4 toxicity was seen in 44% of patient-courses (8/18) with peak serum levels > 10 microM, but only 13% (12/96) with peak serum levels < 10 microM. These results show that cis-RA given at 160 mg/m2 to children achieved serum concentrations known to be effective against neuroblastoma in vitro, and the PK for cis-RA differs from that reported for trans-retinoic acid in children.

A review of the toxicology of air pollutants: toxicology of chemical mixtures

On a temporal basis, air has immense capacity for moving a large mass of pollutants. Mammals and birds are exposed to pollutants in air by the inhalation (nose and mouth), cutaneous or ocular routes. Most laboratory studies on air pollutants have been limited to single air pollutants and very little research has been done on the complex mixture of compounds that exist in ambient air. Complex mixtures are further complicated by dynamic chemical reactions that occur after the emissions leave point sources. Exposure parameters are also important in the toxicity of air pollutants. Intermittent exposure of monkeys to ozone increased the adverse pulmonary effects. Superimposing spikes of 0.8 ppm nitrogen dioxide on a baseline of 0.2 ppm, as occurs on a calm winter day, increased the susceptibility of mice to bacteria-induced pneumonia. Sulfur dioxide at concentrations of 5 ppm increased pulmonary resistance by 39%. Sulfuric acid is the predominate acid particle in the atmosphere. Exposure for 1 h to > 200 micrograms sulfuric acid/m3 depressed bronchomucociliary clearance. Concentrations of 100 micrograms/m3 of photochemical products caused headaches and 510 micrograms/m3 produced cough and chest pain. For chemical interactions in dose response, nitrogen dioxide is synergistic with ozone and ammonium sulfate. When all 3 chemicals are used in mixture, the response was 340%. Atmospheric conditions, such as fog, can alter the toxicity of air pollutants. The dose response to a single chemical can be altered by chemical mixtures and pre-existing disease conditions. Understanding these relationships is important for establishing no observable adverse effect levels. Mechanisms for multiple chemical interactions are multifaceted. One chemical may interfere with the metabolism or detoxification of another. Others may interact at cell receptors. To understand the effects of multiple chemical interactions of air pollutants, there is a need for a blend of epidemiological, laboratory and field studies. Studies are expensive. In the rural agricultural settings, the economic and environmental health risks are high. Should field observations and chemical problems be used as "red flags" for action?

Comparison of ultrasonography and cholangiography (ERCP/PTC) in the differential diagnosis of obstructive jaundice

Diagnostic accuracy of ultrasonography and cholangiography (ERCP/PTC) was compared in determining the site and nature of obstruction in obstructive jaundice. Ultrasound was performed in 50 patients with clinical diagnosis of obstructive jaundice. All patients subsequently underwent ERCP/PTC and/or surgery. ERCP was performed in 38 and PTC in 15 patients. The positive predictive value for the site and etiology of obstruction by ultrasonography was 94% and 86% respectively. In comparison, the cholangiography (ERCP/PTC) had positive predictive value of 100% in site and 98% in etiology. High degree of accuracy and non-invasiveness makes ultrasound as the primary radiological tool in the differential diagnosis of obstructive jaundice. ERCP is the gold standard for determining the precise level and cause of obstruction. PTC adds further to ultrasound based diagnosis of obstructive jaundice particularly in proximal obstruction and in ERCP failure.

Trovafloxacin is active against Toxoplasma gondii

Drugs currently used for treatment of toxoplasmosis in pregnant women, congenital infections, immunocompromised patients, and patients with the ocular disease are not always effective or may be dangerous to use; therefore, there is a need for more-effective and less-toxic drugs. Recently, we examined a group of fluoroquinolones for in vitro and in vivo activities against Toxoplasma gondii. Among those examined in vitro (ciprofloxacin, fleroxacin, ofloxacin, temafloxacin, and trovafloxacin), only trovafloxacin significantly inhibited intracellular replication of T. gondii without significant toxicity for host cells. In a murine model of acute toxoplasmosis, 100 or 200 mg of trovafloxacin per kg of body weight per day for 10 days protected 100% of infected mice against death. A dose of 50 mg/kg/day protected 90% of the mice, and a dose of 25 mg/kg/day effected prolongation of time to death. The other fluoroquinolones did not have such in vivo activities. These results indicate that trovafloxacin may be useful for treatment of toxoplasmosis in humans.

Lymphocyte apoptosis: mediation by increased type 3 inositol 1,4,5-trisphosphate receptor

B and T lymphocytes undergoing apoptosis in response to anti-immunoglobulin M antibodies and dexamethasone, respectively, were found to have increased amounts of messenger RNA for the inositol 1,4,5-trisphosphate receptor (IP3R) and increased amounts of IP3R protein. Immunohistochemical analysis revealed that the augmented receptor population was localized to the plasma membrane. Type 3 IP3R (IP3R3) was selectively increased during apoptosis, with no enhancement of type 1 IP3R (IP3R1). Expression of IP3R3 antisense constructs in S49 T cells blocked dexamethasone-induced apoptosis, whereas IP3R3 sense, IP3R1 sense, or IP3R1 antisense control constructs did not block cell death. Thus, the increases in IP3R3 may be causally related to apoptosis.

Prevalence of seromarkers of HBV and HCV in health care personnel and apparently healthy blood donors

Ninety-five health care workers and 91 controls were screened for seromarkers of both HBV (HBsAg, HBeAg, Anti-HBc) and HCV (anti-HCV) by ELISA. The control group showed a much higher frequency of seromarkers for both the viruses. HBsAg was positive in 5% of study group (health care personnel) and 14% of controls. Anti-HBc as a marker of past HBV-exposure was positive in 28% of study group as compared to 36% of controls. Overall, 33% of study group and 48% of control showed one or the other marker of HBV Anti-HCV was positive in 4% of study group and 14% of controls. This study suggests that health care workers are not particularly a high risk group as compared to rest of the population.

Three-dimensional statistical analysis of sulcal variability in the human brain

Morphometric variance of the human brain is qualitatively observable in surface features of the cortex. Statistical analysis of sulcal geometry will facilitate multisubject atlasing, neurosurgical studies, and multimodality brain mapping applications. This investigation describes the variability in location and geometry of five sulci surveyed in each hemisphere of six postmortem human brains placed within the Talairach stereotaxic grid. The sulci were modeled as complex internal surfaces in the brain. Heterogeneous profiles of three-dimensional (3D) variation were quantified locally within individual sulci. Whole human heads, sectioned at 50 micrometer, were digitally photographed and high-resolution 3D data volumes were reconstructed. The parieto-occipital sulcus, the anterior and posterior rami of the calcarine sulcus, the cingulate and marginal sulci, and the supracallosal sulcus were delineated manually on sagittally resampled sections. Sulcal outlines were reparameterized for surface comparisons. Statistics of 3D variation for arbitrary points on each surface were calculated locally from the standardized individual data. Additional measures of surface area, extent in three dimensions, surface curvature, and fractal dimension were used to characterize variations in sulcal geometry. Paralimbic sulci exhibited a greater degree of anterior-posterior variability than vertical variability. Occipital sulci displayed the reverse trend. Both trends were consistent with developmental growth patterns. Points on the occipital sulci displayed a profile of variability highly correlated with their 3D distance from the posterior commissure. Surface curvature was greater for the arched paralimbic sulci than for those bounding occipital gyri in each hemisphere. On the other hand, fractal dimension measures were remarkably similar for all sulci examined, and no significant hemispheric asymmetries were found for any of the selected spatial and geometric parameters. Implications of cortical morphometric variability for multisubject comparisons and brain mapping applications are discussed.

Rifapentine is active in vitro and in vivo against Toxoplasma gondii

Rifapentine, a derivative of rifamycin, was examined for its in vitro and in vivo activities against the protozoan parasite Toxoplasma gondii. The drug inhibited the intracellular replication of parasites and was not cytotoxic for the host cells at inhibitory concentrations. Mice infected either intraperitoneally with tachyzoites of the RH strain or orally with tissue cysts of the C56 strain were protected against death by treatment with rifapentine. The degree of protection was similar to that induced by atovaquone and apparently higher than that induced by rifabutin. Rifapentine may be a useful drug for the treatment of toxoplasmosis in immunocompromised individuals.

Purification of 2,3-dihydroxybiphenyl 1,2-dioxygenase from Pseudomonas putida OU83 and characterization of the gene (bphC)

The 2,3-dihydroxybiphenyl 1,2-dioxygenase (2,3-DBPD) of Pseudomonas putida OU83 was constitutively expressed and purified to apparent homogeneity. The apparent molecular mass of the native enzyme was 256 kDa, and the subunit molecular mass was 32 kDa. The data suggested that 2,3-DBPD was an octamer of identical subunits. The nucleotide sequence of a DNA fragment containing the bphC region was determined. The deduced protein sequence for 2,3-DBPD consisted of 292 amino acid residues, with a calculated molecular mass of 31.9 kDa, which was in agreement with data for the purified 2,3-DBPD. Nucleotide and amino acid sequence analyses of the bphC gene and its product, respectively, revealed that there was a high degree of homology between the OU83 bphC gene and the bphC genes of Pseudomonas cepacia LB400 and Pseudomonas pseudoalcaligenes KF707.

Laryngeal atresia: antenatal diagnosis in a twin pregnancy

Congenital laryngeal atresia is a rare malformation almost always incompatible with life. Prenatal sonographic diagnosis of this condition has been described on five occasions and all occurred in singleton pregnancies. To our knowledge, this is the first reported case of prenatal diagnosis of laryngeal atresia in a twin pregnancy. A monochorionic diamniotic twin gestation was noted at a routine ultrasound examination at 18 weeks' gestation. One twin was found to have changes consistent with laryngeal atresia with bilateral enlarged hyperechogenic lungs and hydrops fetalis. The other twin appeared normal. A Cesarean section was performed for worsening pre-eclampsia at 29 weeks' gestation. The abnormal twin died, despite resuscitative measures and autopsy confirmed the diagnosis of laryngeal atresia. The presence of the anomaly in only one twin of a monozygotic gestation supports the theory of a developmental anomaly within the branchial arches. Prenatal diagnosis of laryngeal atresia allows prenatal planning for resuscitation at birth, but its presence in one twin of a twin gestation poses several management dilemmas.

Anaesthesia for Cockayne syndrome. Three case reports

Cockayne syndrome is a rare autosomal recessive condition producing a dwarfed, mentally retarded infant or child. Problems with airway management and an increased risk of gastric aspiration are the main anaesthetic concerns. Anaesthetics given to three patients with Cockayne syndrome are described. In two of these, tracheal intubation was difficult and the use of a laryngeal mask airway proved invaluable.

Fine needle aspiration of intra-abdominal masses for cytodiagnosis

Fine needle aspiration cytology was performed in 50 consecutive patients who presented with palpable intra-abdominal mass. Ninety-four per cent (47/50) of the aspirations yielded adequate material for cytological interpretation. Histopathological confirmation was made in all the 50 cases by means of laparotomy and various surgical procedures. Of the 45 proven malignant lesions, fine needle aspirates were diagnosed as positive in 44 (97.33%) cases. There was no false positive result and no complication was encountered.

Reclassification of a polycyclic aromatic hydrocarbon-metabolizing bacterium, Beijerinckia sp. strain B1, as Sphingomonas yanoikuyae by fatty acid analysis, protein pattern analysis, DNA-DNA hybridization, and 16S ribosomal DNA sequencing

A bacterium isolated from a polluted stream, capable of metabolizing biphenyl, naphthalene, phenanthrene, and higher-molecular-weight polycyclic aromatic hydrocarbons (D. Gibson, V. Mahadevan, D. Jerina, H. Yagi, and H. Yeh, Science 189:295-297, 1975), was previously identified as Beijerinckia sp. strain B1. In this investigation, 16S rRNA gene sequencing, biochemical tests, fatty acid methyl ester analysis, polyacrylamide gel electrophoresis of protein, and DNA-DNA hybridization were used to determine the taxonomic relationship of Beijerinckia sp. strain B1. The sequence of the 16S rRNA gene of B1 was identical to that of Sphingomonas yanoikuyae ATCC 51230T. The biochemical tests, fatty acid analysis, and sodium dodecyl sulfate-polacrylamide gel electrophoresis profile of soluble proteins of strain B1 showed results similar to those of S. yanoikuyae. DNA-DNA hybridization indicated that B1 and S. yanoikuyae ATCC 51230T are 75% homologous at the DNA level. We propose that Beijerinckia sp. strain B1 be reclassified as S. yanoikuyae.

Physical, biochemical, and immunological characterization of a thermostable amidase from Klebsiella pneumoniae NCTR 1

An amidase capable of degrading acrylamide and aliphatic amides was purified to apparent homogeneity from Klebsiella pneumoniae NCTR 1. The enzyme is a monomer with an apparent molecular weight of 62,000. The pH and temperature optima of the enzyme were 7.0 and 65 degrees C, respectively. The purified amidase contained 11 5,5-dithiobis(2-nitrobenzoate) (DTNB)-titratable sulfhydryl (SH) groups. In the native enzyme 1.0 SH group readily reacted with DTNB with no detectable loss of activity. Titration of the next 3.0 SH groups with DTNB resulted in a loss of activity of more than 70%. The remaining seven inaccessible SH groups could be titrated only in the presence of 8 M guanidine hydrochloride. Titration of SH groups was strongly inhibited by carboxymethylation and KMnO4, suggesting the presence of SH groups at the active site(s). Inductively coupled plasma-atomic emission spectrometry analysis indicated that the native amidase contains 0.33 mol of cobalt and 0.33 mol of iron per mol of the native enzyme. Polyclonal antiserum against K. pneumoniae amidase was raised in rabbits, and immunochemical comparisons were made with amidases from Rhodococcus sp., Mycobacterium smegmatis, Pseudomonas chlororaphis B23, and Methylophilus methylotrophus. The antiserum immunoprecipitated and immunoreacted with the amidases of K. pneumoniae and P. chlororaphis B23. The antiserum failed to immunoreact or immunoprecipitate with other amidases.

Biochemical effects of Pembina Cardium crude oil exposure in cattle

Crude oil pollution at drilling sites located within or in close proximity to agricultural pasture lands poses serious health risks to cattle raised on these lands. To investigate the clinical and systemic biochemical effects, cattle (8/group) were administered single oral doses of Pembina Cardium crude oil (PCCO) at 16.7, 33.4, and 67.4 g/kg, or water (control group) at 80 g/kg. Cattle exposed to PCCO showed dose-dependent clinical effects. At the lowest dosage, PCCO caused transient and minimal clinical effects; however, high dosages caused varied clinical signs which included tremors, nystagmus, vomiting, and pulmonary distress. On posttreatment day 7 or 30, four cattle from each treatment group were sacrificed and biochemical parameters were assayed in liver, lungs, and kidney cortex. In cattle monitored on posttreatment day 7, the PCCO-treated groups showed marked alterations from the control group in hepatic cytochrome P-450 (P-450), and in aryl hydrocarbon hydroxylase (AHH) and 7-ethoxycoumarin-O-deethylase (ECOD) activities of these tissues. Administration of PCCO caused significant increases (> 100%) in hepatic P-450, but produced variable effects on AHH and ECOD activities in each tissue. The activity of AHH was increased in all tissues; however, the effect was highest in kidney cortex (> 5000%), followed by liver (> 500%) and lungs (> 250%). The activity of ECOD was altered in a differential manner. It was either increased markedly (>1300%) in kidney cortex or increased slightly (20-30%) in liver, but decreased (> 80%) in lungs. The activities of respiratory chain enzymes (succinate-cytochrome c reductase, NADH-cytochrome c reductase and cytochrome oxidase), or NADPH-cytochrome c reductase and glutathione transferase were not changed significantly in any tissues. The alterations in P-450, AHH, and ECOD observed on day 7 were markedly reversed in cattle examined on day 30 posttreatment, indicating a recovery from induced changes. Studies in vitro with hepatic microsomal preparations from day 7 posttreatment groups showed that increases in AHH and ECOD activity in PCCO-treated cattle were due to induction of new isoforms of P-450, as evidenced by (1) the appearance of a 448-nm spectral peak, and (2) differential inhibitory effects of metyrapone and 7,8-benzoflavone on AHH and ECOD activities.

Ophthalmic management of Cockayne's syndrome

Cockayne's syndrome is a rare, autosomal recessive condition which usually presents in early childhood, and is characterised by dwarfism, premature ageing, mental retardation and a typical facial appearance and body habitus. Retinal dystrophy, enophthalmos, strabismus, cataract, nystagmus and corneal opacities are associated ocular features. At a genetic level, a defect occurs in the pathway for the repair of transcriptionally active DNA, and the most common form of Cockayne's is associated with mutations in the human repair gene ERCC6. These patients pose a difficult management problem. A significant proportion will require cataract extraction at an early age, which may present technical difficulties due to enophthalmos, which is a constant finding, poor pupillary dilation and growth retardation. Also, the fitting and assessment of aphakic contact lenses during the post-operative period requires great skill. General anaesthesia in these patients may be hazardous. In particular, difficulty with endotracheal intubation should be anticipated. Two patients with Cockayne's syndrome requiring bilateral cataract extraction in early infancy are presented. The problems associated with surgery, anaesthesia and subsequent follow-up in these mentally retarded infants are discussed.

A review of nonpesticide phosphate ester-induced neurotoxicity in cattle

Nonpesticide phosphate esters induce delayed neurotoxicity in cattle. The most common exposures are to complex mixtures of triaryl phosphate used in lubricating oils. Oral ingestion is most common, but dermal exposures have also occurred. Clinical signs of cholinesterase (ChE) inhibition may or may not be seen. Depending on the biochemical targets, the percent reduction in blood ChE is variable and can be < 30% of normal activity. Organophosphate ester-induced delayed neurotoxicity cannot be predicted by inhibition of blood ChEs. Signs of delayed neurotoxicity occur 2 to 25 d after exposure; these signs are neurologic deficiencies of the antigravity muscles and the muscles of the urinary bladder and larynx. Affected cattle may dribble urine and some may be mute. Signs of ChE inhibition generally are not observed in animals with neurological deficiencies. Pathologic findigs are axonopathy and myelin degeneration of nerves with long axons located in both the peripheral and central nervous systems. In the spinal cord, location of the affected nerve tracts is variable. Degenerative changes occur in motor neurons. Calves are less susceptible to organophosphate ester-induced delayed neurotoxicity than cows. A dose of 500 mg triaryl phosphate/kg body weight will produce complete paralysis in a mature cow in 26 d.