Percutaneous transluminal angioplasty for stenosis of the aorta due to aortic arteritis in children

Percutaneous transluminal balloon angioplasty for stenosis of the aorta due to aortic arteritis was attempted on 45 lesions in 41 children (age range, 4-14 years; mean, 9.9+/-4.2 years) presenting with symptoms of hypertension, severe congestive heart failure, and lower limb claudication. Balloon dilatation was technically successful in 38 (92.7%) patients for 41 stenotic lesions (91.1%). The mean peak systolic pressure gradient (PSG) decreased from 71.7 +/- 23.9 mmHg to 23.2 +/- 17.5 mmHg (p < 0.001) and the diameter of the stenosed segment increased from 3.3 +/- 1.1 mm to 7.5 +/- 2.2 mm (p < 0.001) immediately after angioplasty. Patients with short-segment (<3 cm) stenosis had a lower residual gradient (17.9 +/- 11.1 mmHg vs 30.5 +/- 22.6 mmHg; p < 0.05) and a wider diameter of the aorta (8.8 +/- 1.1 mm vs 7.5 +/- 2.2 mm; p < 0.02) compared to patients with long-segment (>/=3 cm) stenosis. Four patients required stent implantation; 2 for flow-limiting dissection, 1 for failure to reduce PSG by >50%, and 1 for recurrent restenosis. There was marked hemodynamic and angiographic improvement in these 4 patients. Hemodynamic and angiographic restudy in 21 of the 41 patients at mean follow-up period of 6.2 +/- 4.2 months (range, 3-24 months) showed restenosis in 4 (19%) patients. Restenosis was more common in patients with long-segment stenosis than those with short-segment stenosis (30% vs 9.1%). Late restudy in 8 patients, done at 3-7 years after first restudy, showed no recurrence of aortic narrowing. On clinical follow-up of 38 patients for a mean of 58.8 +/- 36.0 months (range, 8-146 months) there was marked improvement in symptoms. Hypertension was cured in 11 (29%), improved in 24 (63%), and persisted in 3 (8%). Six patients with associated severe renal artery stenosis showed further improvement in hypertension after successful renal angioplasty. Severe congestive heart failure improved in 21 (95.4%) of 22 patients. Mean left ventricular ejection fraction improved from 0.32 +/- 0.08 to 0. 48 +/- 0.10 (p < 0.001) at a mean follow-up of 28.7 +/- 8.4 months in these patients. Hemodynamic restudy in 10 of these patients showed improvements in left ventricular end-diastolic pressure from a mean 37 +/- 9 mmHg (range, 25-55 mmHg) to 16.4 +/- 6.2 mmHg (range, 6-25 mmHg) (p < 0.001). Lower limb claudication improved in all 4 patients. Our results suggest that percutaneous transluminal balloon angioplasty in children is safe and highly effective in relieving stenosis of the aorta due to aortic arteritis, with marked clinical improvement, and should be the treatment of choice particularly for discrete stenosis.

Simultaneous detection of erythromycin-resistant methylase genes ermA and ermC from Staphylococcus spp. by multiplex-PCR

A comparative analysis of the two most dominant erythromycin-resistance determinant genes in Staphylococcus sppnamely, the ermA and ermC genes, was carried out. Sixty erythromycin-resistant strains of Staphylococcus spp. were tested, of which 24 were avian and 36 were clinical isolates. Our results indicated the prevalence of ermA over the ermC gene as opposed to the widely held opinion of the ermC gene being the most dominant resistance determinant gene. A multiplex-PCR assay was developed to detect the presence of ermA and ermC genes. Two pairs of primers, specific for the detection of ermA and ermC genes, were used in a multiplex-polymerase chain reaction (PCR) assay to yield amplified DNA products of 610 and 520 bp, respectively. Their digestion with restriction enzyme FokI that yielded a 477 bp and a 132 bp digestion product for ermA and a 333 bp and a 187 bp digestion product for ermC confirmed the authenticity of PCR products. The method could be used to amplify the ermA and ermC genes with as little as 5 pg of template DNA. The use of excess primers or the template DNA resulted in gene-specific amplification and no non-specific amplification was observed by changing the primer to primer or template to primer ratios. Furthermore, no amplification from erythromycin-sensitive S. aureus strain was observed. Using this assay, the poultry strains were found to contain either ermA alone (50%) or a combination of ermA (100%) and ermC (50%) both. The clinical strains contained either ermA (94.5%) or ermC (5.5%) but never both. The gene-specific internal probes were also used to verify the above findings and a high degree of correlation between the multiplex PCR and Southern hybridization data was observed.

Massively dilated esophagus in achalasia: response to pneumatic balloon dilation

OBJECTIVE

Pneumatic balloon dilation is considered by many to be the treatment of choice for achalasia of the esophagus. Patients with untreated, long standing achalasia may develop massively dilated esophagi, sometimes difficult to dilate with a pneumatic balloon and, rarely, may require esophagectomy. We present our experience with nine such patients out of 110 who underwent pneumatic dilation.

METHODS

Of 110 patients treated for achalasia by pneumatic balloon dilation, from January 1989 until December 1996, nine patients had massively dilated esophagi with transverse diameter >7 cm. Results of these patients are presented with pre- and postdilation symptom scores and barium esophagograms. This study was conducted at the Department of Gastroenterology, Shaikh Zayed Postgraduate Medical Institute, Lahore, Pakistan. A Microvasive Rigiflex 35 mm (Boston Scientific, Watertown, MA) pneumatic balloon was used for dilation.

RESULTS

Although it is often tedious to perform pneumatic dilation in massively dilated esophagus, it was possible to dilate adequately, in all nine cases without complications, with good symptomatic improvement at 12-month follow-up.

CONCLUSIONS

We recommend pneumatic balloon dilation in achalasia with massively dilated esophagus as a first line treatment, the failure of which requires surgical intervention.

Quinupristin-dalfopristin is active against Toxoplasma gondii

Synercid and each of its components (quinupristin and dalfopristin) were examined for their activities against Toxoplasma gondii. In vitro, intracellular replication of tachyzoites was inhibited by synercid and each of its two components. The 50% inhibitory concentrations of synercid, quinupristin, and dalfopristin were 1.6, 2.7, and 6.3 microg/ml, respectively. Thus, synercid was markedly more active than its components. Treatment of acutely infected mice with 100 or 200 mg of synercid per kg of body weight per day administered intraperitoneally for 10 days resulted in survival of 50% (P = 0.0002) and 100% (P < 0.0001) of infected mice, respectively, whereas all control mice died by day 18. In contrast, treatment with 200 mg of either quinupristin and dalfopristin per kg per day alone resulted in only 20% survival; treatment with 50 mg of either drug per kg per day resulted only in the prolongation of time to death. These results suggest that synercid may be useful for treatment of toxoplasmosis in humans.

Biochemical and molecular characterization of erthromycin-resistant avian Staphylococcus spp. isolated from chickens

The epidemiology of the two common erythromycin-resistant methylase (erm) genes ermC and ermA was analyzed in 12 coagulase-negative Staphylococcus spp. and 34 coagulase-positive Staphylococcus spp. isolated from chicken. Southern hybridization indicated that only 2 of the 12 coagulase-negative Staphylococcus spp. strains contained the ermC gene on the plasmid; 1 strain of Staphylococcus xylosus harbored the ermC gene on a 2.5-kb plasmid, and 1 strain of Staphylococcus cohnii harbored the gene on a 4.0-kb plasmid. Twelve of the 34 strains of Staphylococcus aureus contained the ermC gene. Eleven of these strains had the ermC gene on a 2.5-kb plasmid, and 1 strain had the gene on a 4.0-kb plasmid. Ten of the 12 coagulase-negative Staphylococcus spp. and 22 of the 34 coagulase-positive Staphylococcus spp. harbored the ermA gene exclusively on the chromosome. Two different ermA EcoRI restriction fragment length polymorphisms (RFLP) were identified. A majority of the isolates was found to have two chromosomal inserts (8.0- and 6.2-kb EcoRI fragments) of ermA. One strain of S. aureus had different chromosomal inserts (6.4- and 5.8-kb EcoRI fragments) of ermA. Our results indicate that either the ermC or ermA gene, homologous to those described in human isolates, was present in all avian Staphylococcus spp. and that ermA was the predominant gene in coagulase-negative and coagulase-positive avian Staphylococcus spp. The size and copy numbers of the ermA gene were different from its human counterpart.

Microscopic Nikolsky's sign

Nikolsky's sign is a useful clinical sign in patients with active pemphigus. It does not however, indicate the level of split in the skin, and is seldom present in partially-treated patients. The purpose of this study was two fold: (i) to document the microscopic or subclinical counterpart of clinical Nikolsky's sign; and (ii) to improve the diagnostic yield of routine histopathology in pemphigus patients in whom the lesions are infected/old and are therefore not useful for histopathology, and when intact blisters are not present; this is particularly useful for institutions in which immunofluorescence facilities are not available. Pemphigus patients were allocated to one of two groups. Group A patients (n = 23) were subjected to manual tangential pressure over the perilesional skin before a biopsy specimen was taken from that site; group B patients (n = 14) were subjected to a biopsy without the tangential pressure technique. Group C consisted of 37 healthy volunteers who were subjected to the tangential pressure technique before a biopsy. Histopathological changes of pemphigus vulgaris or foliaceus were present in 73.9% patients in group A, 28.6% in group B and none in the control group C. Tangential pressure as described below can produce microscopic changes in the epidermis which are diagnostic of pemphigus. These changes are produced at the suprabasal level in pemphigus vulgaris and intraepidermally in pemphigus foliaceus. This technique is of value in those parts of the world where immunofluorescence facilities are not readily available.

Helicobacter pylori in dental plaque of Pakistanis

Helicobacter pylori is now generally accepted to play a key role in acid related and neoplastic pathology of gastroduodenal diseases. Recent reports have concluded that dental plaque is not an important reservoir for Helicobacter pylori, however, these studies did not consider the ethnic background of their subjects nor the amounts of dental plaque present. The aim of this study was to explore the association of Helicobacter pylori dental plaque colonisation in 125 males and 53 females (group I) attending a dental clinic in Pakistan. A simultaneous sample of 30 healthy volunteers with good orodental hygiene consisting of 17 males and 13 females was included as a control group (group II). Six dental plaque specimens were obtained from each subject with a sickle scaler; two were inoculated into CLO test gel and the remaining four were used to prepare cytology slides stained with Giemsa's stain. CLO test was positive in all specimens from group I, while cytology for Helicobacter pylori was positive in 173 cases in this group. One hundred and forty two cases had heavy plaque deposits and all of them were positive on cytology. In group II CLO test was positive in 20 and dental plaque cytology was positive in 7 cases. In conclusion, it is important that future studies into the prevalence of Helicobacter pylori in the oral cavity should take into account the levels of oral cleanliness and the ethnic background of the subjects.

Anti-Toxoplasma gondii activities and structure-activity relationships of novel fluoroquinolones related to trovafloxacin

Eleven novel fluoroquinolones closely related to trovafloxacin were evaluated for their in vitro activity against Toxoplasma gondii, and their structure-activity relationships were examined. The 50% inhibitory concentration (IC50) of trovafloxacin against T. gondii was 2.93 microM; the IC50 of the 11 analogs ranged from 0.53 to 14. 09 microM. Six analogs had IC50s lower than that of trovafloxacin. Examination of the structure-activity relationships of the compounds revealed that addition of a -CH3 at C-5 of the 1,8-naphthyridone ring, at C-2 of the azabicyclohexane ring, or on the -NH2 at the 6 position of the azabicyclohexane ring resulted in a four- to sixfold increase in activity. Moreover, replacement of 2,4-difluorophenyl by cyclopropyl at N-1 of the 1,8-naphthyridone ring increased activity twofold, and moving the -NH2 one atom further away from the azabicyclohexane ring decreased activity. There was no difference between the naphthyridone and quinolone analogs. These results indicate that structure-activity studies of compounds related to drugs active against T. gondii may be useful in producing compounds with more potent activities against the parasite.

Direct in-gel hybridization of digoxigenin-labelled non-radioactive probes

An improved, simple, cost-effective and non-radioactive procedure for in-gel hybridization is described for the detection of signal in dried agarose gels. Large and small digoxigenin-labelled DNA and oligonucleotide probes hybridized efficiently and specifically with the complementary DNA sequences in the gel. The signal-to-noise ratios for the gels dried at 55 degrees C at 1 atmospheric pressure were 3-3.5-fold higher than the gels dried at 25 degrees C under vacuum. The method shows an increased sensitivity over currently available non-radioactive methods for in-gel hybridization. A single copy of a gene insert could be detected by the use of this procedure.

Identification of Aeromonas trota (hybridization group 13) by amplification of the aerolysin gene using polymerase chain reaction

Aeromonas trota is recognized as an important enteropathogen, and its haemolysin (aerolysin) is purported to be one of the virulence factors. Rapid detection and identification of A. trota is important for early and specific diagnosis of the infectious diseases that it causes. Synthetic oligonucleotide primers were used in a polymerase chain reaction (PCR) technique to amplify a species-specific sequence of the aerA gene, which encodes the aerolysin of A. trota. A DNA fragment of 622 bp was amplified from both lysed cells and isolated DNA from A. trota. The identity of the amplified 622 bp fragment was confirmed by digestion with BamH I restriction endonuclease, which produced the predicted 557 and 65 bp fragments. The lower limit for detection of the aerA gene by PCR amplification was 10 pg of total DNA or 10-15 cells ml-1. Primer specificity for A. trota was determined by the PCR assay with cells of 55 strains of Aeromonas sppincluding all of the 14 currently recognized DNA hybridization groups. A strain of Aeromonas enteropelogenes that had been reclassified as A. trota was also PCR positive. The method described here can be used to detect aerolysin-producing A. trota (hybridization group 13) strains from environmental and clinical samples without the use of selective media or additional biochemical tests.

Recombinant bactericidal/permeability-increasing protein (rBPI21) in combination with sulfadiazine is active against Toxoplasma gondii

The activity of recombinant bactericidal/permeability-increasing protein (rBPI21), alone or in combination with sulfadiazine, on the intracellular replication of Toxoplasma gondii was assessed in vitro and in mice with acute toxoplasmosis. rBPI21 markedly inhibited the intracellular growth of T. gondii in human foreskin fibroblasts (HFFs). Following 72 h of exposure, the 50% inhibitory concentration of rBPI21 for T. gondii was 2.6 micrograms/ml, whereas only slight cytotoxicity for HFF cells was observed at the concentrations tested. Subsequent mathematical analyses revealed that the combination of rBPI21 with sulfadiazine yielded slight to moderate synergistic effects against T. gondii in vitro. Infection of mice orally with C56 cysts or intraperitoneally (i.p.) with RH tachyzoites resulted in 100% mortality, whereas prolongation of the time to death or significant survival (P = 0.002) was noted for those animals treated with 5 to 20 mg of rBPI21 per kg of body weight per day. Treatment with rBPI21 in combination with sulfadiazine resulted in significant (P = 0.0001) survival of mice infected i.p. with tachyzoites but not of mice infected orally with T. gondii cysts. These results indicate that rBPI21 is active in vitro and in vivo against T. gondii and that its activity is significantly enhanced when it is used in combination with sulfadiazine. To our knowledge, this is the first report of the activity of rBPI21 against a protozoan parasite.

Effect of clarithromycin and azithromycin on production of cytokines by human monocytes

We examined the in vitro effect of clarithromycin and azithromycin on cytokine production by LPS and Pansorbin stimulated human monocytes. At concentrations that are physiologically achievable, both antibiotics affected in vitro production of IL-1alpha, IL-1beta, IL-6, IL-10, GM-CSF and TNF-alpha to varying degrees. Of those individuals in whom a significant increase or decrease in cytokine production was noted, clarithromycin treatment resulted in a significant suppression of production of each cytokine in 71% and a significant increase in 29% of the individuals. Similar results were noted with azithromycin. The results with IL-6 and TNF-alpha in the clarithromycin studies were most striking. A significant decrease was noted in 60% of individuals for IL-6 and 86% for TNF-alpha. For azithromycin, the most interesting results were for IL-1alpha (decrease in 100% of individuals) and for TNF-alpha (decrease in 100% of individuals). These results show that both clarithromycin and azithromycin alter cytokine production in human monocytes and thus possess immunomodulatory activity.

Identification and sequencing of a cDNA encoding 6-phosphogluconate dehydrogenase from a fungus, Cunninghamella elegans and expression of the gene in Escherichia coli

The fungus, Cunninghamella elegans has been widely used in bioremediation and microbial models of mammalian studies in many laboratories. Using the polymerase chain reaction to randomly amplify the insert directly from the single non-blue plaques of a C. elegans cDNA library, then partly sequencing and comparing with GenBank sequences, we have identified a clone which contains C. elegans 6-phosphogluconate dehydrogenase gene. The polymerase chain reaction product was cloned into a plasmid, pGEM-T Easy vector for full insert DNA sequencing. The 6-phosphogluconate dehydrogenase gene (1458 bases) and the deduced protein sequence were determined from the insert DNA sequence. The gene was found by open reading frame analysis and confirmed by the alignment of the deduced protein sequence with other published 6-phosphogluconate dehydrogenase sequences. Several highly conserved regions were found for the 6-phosphogluconate dehydrogenase sequences. The 6-phosphogluconate dehydrogenase gene was subcloned and over-expressed in a plasmid-E. coli system (pQE30). The cell lysate of this clone has a very high 6-phosphogluconate dehydrogenase enzyme activity. Most of the recombinant protein in this system was formed as insoluble inclusion bodies, but soluble in high concentration of urea-buffer. Ni-NTA resin was used to purify the recombinant protein which showed 6-phosphogluconate dehydrogenase enzyme activity. The recombinant protein has a predicted molecular size correlating with that revealed by sodium dodecylsulfate-polyacrylamide gel electrophoresis analysis. The C. elegans 6-phosphogluconate dehydrogenase was in a cluster with yeast' 6-phosphogluconate dehydrogenase in the phylogenetic tree. Bacterial 6-phosphogluconate dehydrogenase and higher organisms' 6-phosphogluconate dehydrogenase were found in different clusters.

The wandering coronary stent. Case report

Complications associated with coronary stent placement have decreased in recent years. One of the complications involved with this procedure is the possibility that the stent is stripped from the delivery catheter prior to deployment and is lost systemically. This paper reports a rare complication which resulted in vascular insufficiency necessitating surgical intervention.

Predicting hospital mortality in cirrhotic patients: comparison of Child-Pugh and Acute Physiology, Age and Chronic Health Evaluation (APACHE III) scoring systems

OBJECTIVE

The severity of hepatic abnormalities and extent of dysfunction of other organ systems influences prognosis for cirrhosis. The Child-Pugh system has been used to classify cirrhotic patients into good, intermediate, or poor risk categories in evaluation and therapy. Disregard for cardiorespiratory, renal, electrolyte balance, and acid base status limits its predictive accuracy. We evaluated the accuracy of Acute Physiology and Chronic Health Evaluation (APACHE III) to predict short term hospital mortality in patients with liver cirrhosis.

METHODS

A total of 282 patients were prospectively enrolled. Child-Pugh and APACHE III scores were recorded on day 1 for each patient.

RESULTS

Mean age was 51.7+/-11.3 yr, with 65% men and 35% women; 57% presented with upper GI bleeding, 47% encephalopathy, 9% hepatorenal syndrome, and 7% hepatocellular carcinoma. Sixty-three patients (22%) died. Major causes of death were upper GI bleeding 38%, liver failure 21%, hepatorenal syndrome 19%, hepatocellular carcinoma 4%, and spontaneous bacterial peritonitis 6%. Child-Pugh and APACHE III scores for survivors (8.6+/-2.3 and 58.9+/-35.1) were lower than those for nonsurvivors (10.9+/-2.7 and 87.4+/-30.3) (p < 0.001). Using discriminant analysis, APACHE III correctly identified 75% of cases vs 67% of cases for Child-Pugh (p < 0.05). When information regarding ascites and prothrombin time was added to APACHE III, 81% of cases were correctly classified.

CONCLUSION

The APACHE III scoring system is superior to Child-Pugh for prognosticating short term survival of cirrhotic patients. Prognostic accuracy of APACHE III can be enhanced by incorporating information regarding ascites and prothrombin time prolongation.

Use of ketolides in combination with other drugs to treat experimental toxoplasmosis

Because combination therapy is required to treat human toxoplasmosis, we examined combinations of the ketolides HMR 3004 and HMR 3647 with atovaquone, clindamycin or sulphadiazine in a murine model of toxoplasmosis. An oral dose of 50 mg/kg/day of HMR 3004 protected 30% of mice lethally infected with Toxoplasma gondii. The same dose protected 100% of infected mice when administered in combination with non-protective doses of atovaquone, clindamycin or sulphadiazine. Similar results were noted with 25 mg/kg/day of HMR 3647. These results demonstrate that these drug combinations are highly effective for treating toxoplasmosis in mice.

Isolation and characterization of Enterobacter cloacae capable of metabolizing asparagine

A gram-negative, rod-shaped bacterium capable of utilizing L-asparagine as its sole source of carbon and nitrogen was isolated from soil and identified as Enterobacter cloacae. An intracellularly expressed L-asparaginase was detected and it deaminated L-asparagine to aspartic acid and ammonia. High-pressure liquid chromatography analysis of a cell-free asparaginase reaction mixture indicated that 2.8 mM L-asparagine was hydrolyzed to 2.2 and 2.8 mM aspartic acid and ammonia, respectively, within 20 min of incubation. High asparaginase activity was found in cells cultured on L-fructose, D-galactose, saccharose, or maltose, and in cells cultured on L-asparagine as the sole nitrogen source. The pH and temperature optimum of L-asparaginase was 8.5 and 37-42 degrees C, respectively. The half-life of the enzyme at 30 degrees C and 37 degrees C was 10 and 8 h, respectively.

Two 2-hydroxy-3-alkyl-1,4-naphthoquinones with in vitro and in vivo activities against Toxoplasma gondii

Two 3-alkyl-substituted 2-hydroxy-1,4-naphthoquinones, NSC 113452 (NSC52) and NSC 113455 (NSC55), were evaluated for activity against Toxoplasma gondii in vitro and in murine models of acute toxoplasmosis. In vitro, both NSC52 and NSC55 significantly inhibited intracellular replication of T. gondii. In vivo, each compound was examined alone and in combination with other drugs currently used for treatment of human toxoplasmosis. Although none of the compounds protected mice against death when administered orally, both were significantly protective when administered intraperitoneally. In addition, a significant increase in survival was observed when suboptimal doses of each compound were used in combination with suboptimal doses of pyrimethamine or sulfadiazine. These results indicate that combinations of NSC52 or NSC55 with pyrimethamine or sulfadiazine have promising activity against T. gondii.

Cortical variability and asymmetry in normal aging and Alzheimer's disease

The onset of Alzheimer's disease (AD) is accompanied by a complex and distributed pattern of neuroanatomic change, difficult to distinguish clinically from dynamic alterations in normal aging. Extreme variations in the sulcal patterns of the human cortex have made it difficult to identify diffuse and focal variations in cortical structure in neurodegenerative disease. We report the first comprehensive 3D statistical analysis of deep sulcal structure in vivo, in both normal aging and dementia. High-resolution 3D T1-weighted fast SPGR (spoiled GRASS) MRI volumes were acquired from 10 patients diagnosed with AD (NINCDS-ARDRA criteria; age: 71.9 +/- 10.7 years) and 10 normal subjects matched for age (72.9 +/- 5.6 years), gender, educational level and handedness. Scans were digitally transformed into Talairach stereotaxic space. To determine specific patterns of cortical variation in dementia patients, 3D average and probabilistic maps of primary deep sulci were developed for both normal and AD groups. Major sulci (including supracallosal, cingulate, marginal, parieto-occipital, anterior and posterior calcarine sulci, and Sylvian fissures) were modeled as complex systems of 3D surfaces using a multi-resolution parametric mesh approach. Variations and asymmetries in their extents, curvature, area and surface complexity were evaluated. Three-dimensional maps of anatomic variability, structural asymmetry and local atrophy indicated severe regionally selective fiber loss in AD. A midsagittal area loss of 24.5% at the corpus callosum's posterior midbody (P < 0.025) matched increases in structural variability in corresponding temporo-parietal projection areas. Confidence limits on 3D cortical variation, visualized in 3D, exhibited severe increases in AD from 2 to 4 mm at the callosum to a peak SD of 19.6 mm at the posterior left Sylvian fissure. Normal Sylvian fissure asymmetries (right higher than left; P < 0.0005), mapped for the first time in three dimensions, were accentuated in AD (P < 0.0002), and were greater in AD than in controls (P < 0.05). Severe AD-related increases in 3D variability and asymmetry may reflect disease-related disruption of the commissural system connecting bilateral temporal and parietal cortical zones, regions known to be at risk of early metabolic dysfunction, perfusion deficits and selective neuronal loss in AD.

Band ligation vs endoscopic sclerotherapy in esophageal varices: a prospective randomized comparison

OBJECTIVE

A prospective randomized trial was conducted to compare efficacy, safety and complications of band ligation (BL) with sclerotherapy (Scl).

METHODS

Patients with esophageal variceal bleeding were randomized into two study groups. BL (group A) was done in 28 patients whereas 30 patients (group B) had Scl. After initial treatment, follow-up sessions were repeated by the same method every two weeks till obliteration or reduction to grade 1. Subsequent sessions of endoscopy were done every three months, same procedure was repeated for recurrence of varices and for any episode of rebleeding.

RESULTS

Initial control of bleeding by Scl was achieved in 22 of 28 patients (78%) and in 23 of 24 patients (96%) with BL. Eradication of varices was significantly better achieved in BL group, with less treatment sessions required in Group A as compared with group B 2 +/- 1.2 vs 5 +/- 2.5, P < 0.001). Major complications (3% vs 16%, P < 0.05) as well as mortality (11% vs 21%, P > 0.05) was higher in group B.

CONCLUSION

Band ligation was more effective mode of treatment and was associated with lesser early mortality and complications as compared with sclerotherapy.

Molecular cloning, nucleotide sequence, and expression in Escherichia coli of a hemolytic toxin (aerolysin) gene from Aeromonas trota

Aeromonas trota AK2, which was derived from ATCC 49659 and produces the extracellular pore-forming hemolytic toxin aerolysin, was mutagenized with the transposon mini-Tn5Km1 to generate a hemolysin-deficient mutant, designated strain AK253. Southern blotting data indicated that an 8.7-kb NotI fragment of the genomic DNA of strain AK253 contained the kanamycin resistance gene of mini-Tn5Km1. The 8.7-kb NotI DNA fragment was cloned into the vector pGEM5Zf(-) by selecting for kanamycin resistance, and the resultant clone, pAK71, showed aerolysin activity in Escherichia coli JM109. The nucleotide sequence of the aerA gene, located on the 1.8-kb ApaI-EcoRI fragment, was determined to consist of 1,479 bp and to have an ATG initiation codon and a TAA termination codon. An in vitro coupled transcription-translation analysis of the 1.8-kb region suggested that the aerA gene codes for a 54-kDa protein, in agreement with nucleotide sequence data. The deduced amino acid sequence of the aerA gene product of A. trota exhibited 99% homology with the amino acid sequence of the aerA product of Aeromonas sobria AB3 and 57% homology with the amino acid sequences of the products of the aerA genes of Aeromonas salmonicida 17-2 and A. sobria 33.

Unusual clinical variants of cutaneous leishmaniasis in Pakistan

Cutaneous leishmaniasis is endemic in the Baluchistan province of Pakistan and poses a great risk to non-immune visitors to the area. The wide spectrum of clinical variants of this common disease is at times a diagnostic challenge. A total of 1709 patients with cutaneous leishmaniasis were recorded over a 1-year period. In 37 (2%) patients the lesions were very unusual, and therefore worth reporting. These included acute paronychial, chancriform, annular, palmoplantar, zosteriform and erysipeloid forms. The zosteriform and erysipeloid forms have rarely been reported previously, but to the best of our knowledge, acute paronychial, chancriform, annular and palmoplantar lesions are being reported for the first time. The morphologically unusual lesions may be attributed to an altered host response or involvement of an atypical strain of parasite in these lesions.

Hiatal hernia in achalasia

Barium esophagograms of 89 patients out of 110 with manometrically proven achalasia were reviewed. Only four (4.4%) patients showed association of hiatal hernia, indicative of its rare occurrence. Presence of hiatal hernia, is said to have less likelihood of associated achalasia but this association does exist as per our report and that of others.

Pneumatic balloon dilation in achalasia: a prospective comparison of balloon distention time

OBJECTIVE

Duration of Inflation in pneumatic balloon dilatation as treatment of achalasia has been variable ranging from 15 s to 6 min. A 60 s duration appears to be most often used. We compared the efficacy of dilation of achalasia with either 6- or 60-s inflation duration using a Rigiflex dilator of 3.0 cm diameter.

METHODS

Eighty-one consecutive patients were prospectively studied in a randomized fashion, 41 in the 60-s group (A) and 40 patients in the 6-s group (B). Mean age of group A was 43 +/- 16.2 yr and of group B was 40 +/- 16.4 yr. Symptoms of dysphagia, chest pain, heartburn, regurgitation, and night cough were evaluated at basal (before dilation), 1- and 6-month intervals after dilation in both groups. Barium swallow was done to assess esophageal emptying 1 wk before dilation and 5 min postdilation in both groups.

RESULTS

Significant and sustained improvement was seen for all symptoms in both groups. In addition, the degree of improvement in symptom scores between the two groups was similar. Barium esophagram in both groups at basal and immediately postdilation showed significant improvement in barium emptying but there was no significant difference between the two groups, indicative of equal efficacy in both distention times. Two patients needed repeat dilatation in group A and one in group B, with one drop out from group A, who was lost to follow-up, and was excluded from the analysis. No perforation occurred.

CONCLUSION

Short duration of pneumatic balloon dilatation (6-s) is as effective as longer duration (60-s) in treatment of achalasia.

Hepatocellular carcinoma: analysis of 76 cases

Hepatocellular carcinoma is one of the most common malignancies world wide. We present data on 76 patients admitted to the Shaikh Zayed Hospital. Mean age was 52.2 +/- 11.3 years. Eighty six percent were males and 14% females. Eighty-six percent patients had underlying cirrhosis documented on ultrasound examination. Seventy-five percent were positive for anti HCV, 10% for HBsAg positive, 10% for both HBsAg and anti HCV and 5% cases had negative viral serology. Main clinical features were abdominal pain, weight loss, jaundice, hepatomegaly and ascites. Forty-three percent patients were Child-Pugh class A, 30% class B and 13% class C and 14% were non cirrhotic. Mean alfa fetoprotein levels were 142 +/- 155 ng/ml (range 2.7 to 1470). Diagnosis of hepatocellular carcinoma was established in 60 patients by fine needle aspiration biopsy under ultrasound guidance. Two patients died after biopsy due to uncontrollable bleeding. Fifty-four percent patients had a solitary lesion and 46% had multifocal or diffuse lesions. The average size of lesion was 7.8 x 8.1 cm. Twenty-two patients received intralesional alcohol injection. Fifty-four percent of these with a tumor size greater than 8 cm died during follow up. The major cause of death was liver failure in 8 patients and fatal bleeding occurred in 4 patients. Hepatocellular carcinoma has a high prevalence in middle aged males with a strong association with anti HCV positive cirrhosis. Patients with a tumour size greater than 8 cm have a poor response to intralesional alcohol injection.

Effect of trovafloxacin on production of cytokines by human monocytes

Antibiotics have previously been shown to have immunomodulatory effects. We examined the effect of the broad-spectrum fluoroquinoline antibiotic trovafloxacin on cytokine synthesis by monocytes obtained from healthy human volunteers and stimulated with either lipopolysaccharide or gram-positive cells (heat-killed Staphylococcus aureus [Pansorbin]). Trovafloxacin levels achievable in humans suppressed in vitro synthesis of each of the cytokines analyzed, viz., interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-6, IL-10, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor alpha. This effect was not due to direct effects of the drug on cellular viability; at these concentrations, trovafloxacin did not have demonstrable cytotoxicity for the monocytes, as determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. Although similar patterns of suppression of cytokine synthesis were observed in samples obtained from the same volunteers on different days, there were significant day-to-day variations. These results reveal that trovafloxacin possesses significant immunomodulatory activity in vitro and suggest that suppression of acute-phase inflammatory responses may occur in vivo, elicited through trovafloxacin's effect on cytokine synthesis by human monocytes.

Independent prognostic significance of ischemic ST-segment response limited to recovery from treadmill exercise in asymptomatic subjects

BACKGROUND

Although exercise-induced ST depression is an independent predictor of future coronary events in asymptomatic populations, the predictive value of ST depression beginning after exercise cessation is unknown.

METHODS AND RESULTS

We analyzed the treadmill exercise tests of 825 healthy volunteers who were 22 to 89 years of age from the Baltimore Longitudinal Study of Aging. All subjects were free from coronary heart disease by history, physical examination, and resting ECG. From 825 participants, 611 (group 0) had no ischemic ST-segment changes during or after treadmill exercise, while 214 subjects developed > or = 1-mm flat or downsloping ST depression: 151 (group 1) had ST changes starting during exercise, and 63 (group 2) had changes limited to recovery. Groups 1 and 2 were similar in age, sex, smoking status, hypertension prevalence, fasting plasma glucose, and serum cholesterol (CHOL). However, both groups were older and had higher CHOL and prevalence of hypertension than group 0. Treadmill exercise duration, peak oxygen consumption, and maximal heart rate were similar between groups 1 and 2 but were lower than in group 0 (each P < 0.05). During a mean follow-up time of 9 years, 55 subjects developed coronary events (angina pectoris, myocardial infarction, or coronary death): 21 of 611 (3.4%) in group 0, 22 of 151 (14.6%) in group 1, and 12 of 63 (19%) in group 2 (P = 0.001). By survival analysis, the risk of coronary events was similar in groups 1 and 2 but significantly higher than in group 0 (P < 0.0001). Multiple logistic regression showed that age (odds ratio [OR] = 1.07 per year, P = 0.00001), CHOL (OR = 1.02 per 1 mg, P = 0.0001), and presence of ST-segment depression (OR = 2.59, P = 0.007 and OR = 2.38, P = 0.04 for groups 1 and 2, respectively) were independent predictors of events.

CONCLUSIONS

Thus, ischemic ST-segment changes developing during recovery from treadmill exercise in apparently healthy individuals have adverse prognostic significance similar to those appearing during exercise.

Rapid method for the detection of genetically engineered microorganisms by polymerase chain reaction from soil and sediments

A rapid and sensitive method for the detection of genetically engineered microorganisms in soil and sediments has been devised by in vitro amplification of the target DNAs by a polymerase chain reaction. A cloned catechol 2,3-dioxygenase gene located on the recombinant plasmid pOH101 was transferred to Pseudomonas putida MMB2442 by triparental crossing and used as a target organism. For the polymerase chain reaction from soil and sediment samples, the template DNA was released from a 100-mg soil sample. Bacterial seeded soil samples were washed with Tris-EDTA buffer (pH 8.0) and treated with a detergent lysis solution at 100 degrees C. After addition of 1% polyvinylpolypyrrolidine solution, the samples were boiled for 5 min. Supernatant containing nucleic acid was purified with a PCR purification kit. The purified DNA was subjected to polymerase chain reaction, using two specific primers designed for the amplification of catechol 2,3-dioxygenase gene sequences. The detection limit was 10(2) cells per gram of soil. This method is rapid and obviates the need for lengthy DNA purification from soil samples.

Glyceraldehyde-3-phosphate dehydrogenase: nuclear translocation participates in neuronal and nonneuronal cell death

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) protein levels increase in particulate fractions in association with cell death in HEK293 cells, S49 cells, primary thymocytes, PC12 cells, and primary cerebral cortical neuronal cultures. Subcellular fractionation and immunocytochemistry reveal that this increase primarily reflects nuclear translocation. Nuclear GAPDH is tightly bound, resisting extraction by DNase or salt treatment. Treating primary thymocytes, PC12 cells, and primary cortical neurons with antisense but not sense oligonucleotides to GAPDH prevents cell death. Because cell-death-associated nuclear translocation of GAPDH and antisense protection occur in multiple neuronal and nonneuronal systems, we propose that GAPDH is a general mediator of cell death and uses nuclear translocation as a signaling mechanism.

Detection of erythromycin resistant methylase gene by the polymerase chain reaction

A polymerase chain reaction (PCR) protocol was developed that could specifically amplify a 520-bp region of the erythromycin resistant methylase (ermC) gene sequence. The identity of the PCR-amplified 520-bp DNA was confirmed by HinCII endonuclease restriction digestion, which produced the predicted 440-bp and 80-bp DNA fragments. A 20-mer (alpha-32P) oligonucleotide probe specifically hybridized with these amplified products confirming the specificity and reliability of this diagnostic assay. The assay could detect the ermC gene in bacterial suspensions containing as few as 10(3) cells ml-1. The assay was used to detect the presence of the ermC gene in several Gram-positive bacterial strains identified as Streptococcus sp., Staphylococcus sp., Micrococcus sp., Lactobacillus sp. and Enterococcus sp., isolated from water samples maintained in experimental animal cages and clinical sources. Only bacteria identified as Staphylococcus sp. were resistant to the antibiotic. Although 17 strains of Staphylococcus sp. isolated from clinical samples were resistant to erythromycin, only seven of these isolates tested positive for the presence of the ermC gene. Of these strains, five were identified as coagulase-positive S. aureus and the rest were identified as coagulase-negative S. epidermidis. The erythromycin resistance in all seven ermC positive isolates was constitutive. The entire diagnostic assay, including template preparation, amplification and electrophoresis can be completed within 6 h.

Pemphigus vulgaris autoantibody response is linked to HLA-DQB1*0503 in Pakistani patients

Pemphigus vulgaris (PV) is an autoimmune disease of the skin and mucous membranes characterized by an autoantibody response against an epidermal cadherin. We performed high resolution HLA class II typing in 19 patients with PV from Rawalpindi, Pakistan and 19 non-Jewish European PV patients from Boston by sequence-specific oligonucleotide probe hybridization. The results were compared with two separate ethnically matched control populations. WE found that PV patients from Pakistan had significantly increased frequencies of DRB1*1404 (p = 0.01), DQA1*0101 (p = 0.02), and DQB1*0503 (p = 0.01). Among the patients of non-Jewish European ancestry, DRB1*1401 (p < 10(-6)), DQA1*0101 (p < 10(-5)) and DQB1*0503 (p < 10(-6)), were increased in PV patients. Formal linkage analysis between the major histocompatibility complex and the PV antibody was performed in 67 relatives of the 19 Pakistani patients. The results showed strong evidence for linkage of HLA-DRB1*1404, DQA1*0101, DQB1*0503, with the presence of PV antibody in relatives' families with a significant logarithm of the odds score of 6.06. Based on the three dimensional structure of class II molecules, we propose that HLA-DQA1*0101 and DQB1*0503, encode a negatively charged P9 peptide binding pocket of the DQ molecule and are significantly associated with susceptibility to PV in non-Jewish populations.

The ketolide antibiotics HMR 3647 and HMR 3004 are active against Toxoplasma gondii in vitro and in murine models of infection

Ketolides are a new class of macrolide antibiotics that have been shown to be active against a variety of bacteria including macrolide-resistant bacteria and mycobacteria. We examined two ketolides, HMR 3647 and HMR 3004, for their in vitro and in vivo activities against the protozoan parasite Toxoplasma gondii. In vitro, both ketolides at concentrations as low as 0.05 microg/ml markedly inhibited replication of tachyzoites of the RH strain within human foreskin fibroblasts. HMR 3004 demonstrated some toxicity for host cells after they were exposed to 5 microg of the drug per ml for 72 h. In contrast, HMR 3647 did not show any significant toxicity even at concentrations as high as 25 microg/ml. In vivo, both ketolides provided remarkable protection against death in mice lethally infected intraperitoneally with tachyzoites of the RH strain or orally with tissue cysts of the C56 strain of T. gondii. A dosage of 100 mg of HMR 3647 per kg of body weight per day administered for 10 days protected 50% of mice infected with tachyzoites. The same dosage of HMR 3004 protected 100% of the mice. In mice infected with cysts, a dosage of 30 mg of HMR 3647 per kg per day protected 100% of the mice, whereas a dosage of 40 mg of HMR 3004 per kg per day protected 75% of the mice. These results demonstrate that HMR 3647 and HMR 3004 possess excellent activities against two different strains of T. gondii and may be useful for the treatment of toxoplasmosis in humans.

Nucleotide sequence of the gene encoding cis-biphenyl dihydrodiol dehydrogenase (bphB) and the expression of an active recombinant His-tagged bphB gene product from a PCB degrading bacterium, Pseudomonas putida OU83

The nucleotide sequence of the bphB gene of Pseudomonas putida strain OU83 was determined. The bphB gene, which encodes cis-biphenyl dihydrodiol dehydrogenase (BDDH), was composed of 834 base pairs with an ATG initiation codon and a TGA termination codon. It can encode a polypeptide of 28.91 kDa, containing 277 amino acids. Promoter-like and ribosome-binding sequences were identified upstream of the bphB gene. The bphB nucleotide sequence was used to produce His-tagged BDDH, in Escherichia coli. The His-tagged BDDH construction, carrying a single 6 x His tail on the N-terminal portion, was active. The molecular mass of the native enzyme was 128 kDa and on SDS-PAGE analysis the molecular mass was 31 kDa. This enzyme requires NAD+ for its activity and its optimum pH is 8.5. Nucleotide and the deduced amino acid sequence analyses revealed a high degree of homology between the bphB gene from Pseudomonas putida OU83 and the bphB genes from P. cepacia LB400 and P. pseudoalcaligenes KF707.

Rapid purification of an active recombinant His-tagged 2,3-dihydroxybiphenyl 1,2-dioxygenase from Pseudomonas putida OU83

2,3-Dihydroxybiphenyl 1,2-dioxygenase (2,3-DBPD) is an extradiol-type dioxygenase that catalyzes the aromatic ring fission of 2,3-dihydroxybiphenyl, the third step in the biphenyl degradation pathway. The nucleotide sequence of the Pseudomonas putida OU83 gene bphC, which encodes 2,3-DBPD, was cloned into a plasmid pQE31. The His-tagged 2,3-DBPD produced by a recombinant Escherichia coli strain, SG13009(pREP4)(pAKC1), and purified with a Ni-nitrilotriacetic acid resin affinity column using the His-bind Qiagen system. The His-tagged 2,3-DBPD construction, carrying a single 6 x His tail on the N-terminal of the polypeptide, was active. SDS-PAGE analysis of the purified active 2,3-DBPD gave a single band of 34 kDa; this is in agreement with the size of the bphC coding region. The K(m) for 2,3-dihydroxybiphenyl was 14.5 +/- 2 microM. The enzyme activity was enhanced by ferrous ion but inhibited by ferric ion. The enzyme activity was inhibited by thiol-blocking reagents and heavy metals HgCl2, CuSO4, NiSO4, and CdCl2. The yield was much higher and the time required to purify recombinant 2,3-DBPD from clone pAKCl was faster than by the conventional chromatography procedures.

Right hemidiaphragmatic twitching: a complication of bipolar atrial pacing

A patient with an atrioventricular sequential pacemaker developed rhythmic contractions of the right hemidiaphragm. This was found to be the result of right phrenic nerve stimulation, which was directly related to the wide distance between the poles of an ELA atrial lead when pacing in bipolar mode. Pole separation in current atrial leads is discussed.

Tropical calcific pancreatitis and fibrocalculus pancreatic diabetes in Bangladesh

The relationship between tropical calcific pancreatitis (TCP) and fibrocalculus pancreatic diabetes (FCPD) is still unclear. The clinical, biochemical and radiological data of age-matched TCP and FCPD subjects have been briefly discussed in the present review. Fibrocalculus pancreatic diabetes patients present with a significantly lower BMI compared with TCP patients. Analysis of the family history reveals that some kind of environmental factors seem to play a predominant role in the development of diabetes in FCPD patients, although these factors remain to be identified. Both TCP and FCPD patients predominantly come from a rural background. Fasting and 2 h blood glucose values as well as fructosamine levels in FCPD patients are approximately four-times higher than those of TCP patients. Measurements of early renal haemodynamic and microvascular changes (glomerular filtration rate, kidney size, microalbuminuria and microtransferrinuria) indicate an early renal involvement in FCPD patients. Tropical calcific pancreatitis subjects have approximately twice as high fasting C-peptide values compared with FCPD patients. Findings of single stranded DNA measurements suggest the involvement of oxidative damage in FCPD patients. Ketosis resistance is the most conspicuous clinical feature in the FCPD group and this relative absence of ketosis is probably due to a defect in the ketone body synthesis pathway and/or in the regulation of counterbalancing hormones. Endoscopic retrograde pancreatography findings of TCP and FCPD patients suggest that FCPD should not be considered only as a form of secondary diabetes consequent to generalized pancreatic damage in TCP.

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.