Prevalent Serotypes of Pasteurella multocida Isolated from Different Animal and Avian Species in India

Identification and estimation of the prevalence of Pasteurella multocida organisms in different animal and avian species in India during November 2000 to July 2003 was carried out. Out of 418 samples collected from different outbreaks suspected to be caused by P. multocida, a total of 206 bacterial cultures were identified as P. multocida on the basis of cultural, morphological and biochemical characteristics. All the 206 cultures were isolated from different domestic animal species (cattle, buffalo, sheep, goat, pig and rabbit), avian species (chicken, duck, quail, turkey, goose) and wild animals such as leopard and deer. Serotyping of P. multocida cultures revealed the presence of various serotypes (A:1, A:3, A:1,3, A:4, B:2, D:1 and -:1) among the livestock population. P. multocida polymerase chain reaction (PCR) assay applied on different forms of bacterial cultures (bacterial culture lysate, direct bacterial colony and mixed bacterial culture lysate) yielded an amplified product of approximately 460 bp specific for P. multocida. The results of PCR assay correlated well with conventional methods of identification. The present investigation revealed the presence of varied serotypes among livestock and PCR assay was found to be useful for rapid, sensitive and specific diagnosis of pasteurellosis in animals and avian species.

Molecular variability among strains of Pasteurella multocida isolated from an outbreak of haemorrhagic septicaemia in India

The applicability of conventional and molecular methods for rapid detection and differentiation of Pasteurella multocida serogroup B isolates involved in an outbreak of haemorrhagic septicaemia affecting Indian buffaloes, was studied. Five isolates were obtained and were subjected to phenotypic and genotypic characterization. None of the five isolates could be differentiated on the basis of cultural, biochemical, pathogenicity and antimicrobial sensitivity patterns. Polymerase chain reaction (PCR)-based techniques were found to be specific and sensitive for rapid detection and differentiation of isolates. Repetitive extragenic palindromic (REP-) PCR, enterobacterial repetitive intergenic consensus (ERIC-) PCR and single-primer PCR differentiated all the five isolates into different profiles. All the isolates involved in the outbreak were found to have a genetic profile different from standard P. multocida strain (P52). However, three isolates had similar profiles, whereas each of the remaining two had a different profile. The study indicates the involvement of multiple strains of P. multocida in a single outbreak of haemorrhagic septicaemia in buffaloes. The results also indicate that molecular methods of detection and typing are superior to conventional methods for rapid epidemiological investigations of haemorrhagic septicaemia.

Specific identification of Pasteurella multocida serogroup-A isolates by PCR assay

A polymerase chain reaction (PCR) assay targeting the hyaC-hyaD gene was developed and used to identify strains of Pasteurella multocida belonging to serogroup-A. A set of serogroup-specific-PCR primers amplified a 564 bp product from genomic DNA prepared from bacterial cells or directly from bacterial colonies. This method detected as low as 10 ng of bacterial DNA and had a specificity of 100% for P. multocida serogroup-A. A nested PCR method yielded a single 374 bp product. All fifty isolates were also shown to be identical by restriction fragment length polymorphism (RFLP) analysis of the PCR products after digestion with BglII.

Fatal intentional poisoning cases admitted to the University Hospitals of Leuven, Belgium from 1993 to 1996

Between January 1993 and July 1996, a total of 2827 intentional cases of poisoning were registered in the University Hospitals of Leuven, Belgium. Ten of these cases were fatal. This study was set up to evaluate the substances involved, the circumstances, the features and the characteristics of the patients who died due to intentional poisoning. The male to female ratio of these fatal cases was 9 : 1. The median age was 43 years. Two groups of substances were revealed to be associated with fatal outcome. The first group consisted of chemicals (seven lethal cases): cholinesterase inhibitors ( =3), methanol ( =2) and paraquat ( =2). The second group consisted of benzodiazepines (three lethal cases). In the cases of poisoning with chemicals, death was directly related to product toxicity and the severity of the poisoning, whilst with benzodiazepines, which are considered to be relatively safe drugs even when taken in overdose, there was a clear relationship between a fatal outcome and a delay between ingestion and medical support. Product toxicity, complications and a delay in medical support may be considered as predictors for the effectiveness and efficacy of treatment and may influence which medical treatments need to be administered.

New molecular arrays based on a tin(IV) porphyrin scaffold

Two new porphyrin arrays-a hexamer and a nonamer-have been synthesized and characterized by elemental analysis as well as mass, (1)H NMR, and UV-vis spectroscopic methods. The scheme of construction of these arrays employs a synthetic protocol involving sequential "organic" and "inorganic" reactions conducted, respectively, at the peripheral meso-phenyl ring and the central tin(IV) ion of the porphyrin scaffold. The architecture of the hexamer is such that it is based on a covalently linked tin(IV) porphyrin dimer, with each of the two tin(IV) centers trans-axially ligated to two free-base porphyrins, while the higher homologue features a tin(IV) porphyrin trimer as the basal unit, with its central metalloid ions having two free-base porphyrins as axial ligands. This extended, "axial-bonding"-type architecture of the new arrays has been investigated by the (1)H NMR method, which reveals characteristic ring-current-induced shifts and coupling patterns for the resonances due to protons of the axial free-base porphyrin subunits. The presence of any ring-ring (basal-basal, basal-axial, or axial-axial) interaction in these arrays is not obvious from their UV-vis and redox potential data, which are close to those of the corresponding constituent monomeric species. On the other hand, their singlet-state activities are quite different from those of the precursor reference compounds as probed by steady-state fluorescence. The results of the detailed investigations carried out on these hybrid, "bichromophoric" arrays have been interpreted in terms of the occurrence of intraarray, interchromophore energy- and electron-transfer reactions.

Ocular and systemic lesions in children with HIV

The spectrum of ocular lesions in children with HIV infection is different from that seen in adults. Ocular lesions in pediatric AIDS patients have not been studied in India. We analyzed the clinical profile, demographic characteristics, ocular and systemic lesions in children with AIDS seen in a referral eye institute in India. The clinical profile and demographic features were studied and complete ocular examination was done. Systemic findings were evaluated at an AIDS care center and recorded in a precoded proforma. Out of the 218 cases of HIV infection seen at our hospital between December 1993 and October 1999, 12 (5.50%) were below 15 years of age. Seven (58.33%) were males and 5 (41.66%) were females with the mean age of 6.5 years and median age of 6.2 years. Vertical transmission was the most common mode of infection (58.33%). Seven (58.33%) of these patients had systemic infection, the most common being pulmonary tuberculosis (42.85%). Ocular lesions were found in 6 (50%) patients. The most common ocular lesions were anterior uveitis and cytomegalovirus retinitis (CMV) (33%) followed by retinal detachment (16.66%) and vitreous hemorrhage (16.66%). High prevalence of ocular lesions in pediatric AIDS patients in India in a referral eye centre was observed. The most common lesions were anterior uveitis followed by CMV retinitis. The management in such cases was often challenging in a developing country like India.

Electrical impedance cardiography using artificial neural networks

This study evaluates the use of artificial neural networks to estimate stroke volume from pre-processed, thoracic impedance plethysmograph signals from 20 healthy subjects. Standard back-propagation was used to train the networks, with Doppler stroke volume estimates as the desired output. The trained networks were then compared to two classical biophysical approaches. The coefficient of determination (R2 x 100%) between the biophysical approaches and the Doppler was 8.20% and 9.90%, while it was 77.38% between the best neural network and the Doppler. Among these methods, only the neural network residuals had a significant zero mean Gaussian distribution (alpha=0.05). Our results indicate that an invertible relationship may exist between thoracic bioimpedance and stroke volume, and that artificial neural networks may offer a potentially advantageous approach for estimating stroke volume from thoracic electrical impedance, both because of their ease of use and their lack of confounding assumptions.

The effect of paroxetine on thiothixene pharmacokinetics

OBJECTIVE

In this study healthy volunteers received thiothixene with and without a 3-day pretreatment with paroxetine to determine if paroxetine decreased the clearance of thiothixene.

METHOD

Ten healthy medication-free volunteers (4 women and 6 men, mean age 38 +/- 12 years) were randomized to receive a single 20 mg oral dose of thiothixene on two separate occasions. On one occasion thiothixene was given concurrently, and following 3 days of pre-treatment with oral paroxetine (20 mg/day). On the other occasion thiothixene was given without paroxetine pre-treatment. The two study days were separated by a minimum period of 2 weeks. On both study days, after the administration of thiothixene, 10 ml blood samples were collected over the next 72 h.

RESULTS

None of the pharmacokinetic parameters of thiothixene were significantly altered by a 3-day treatment with paroxetine.

DISCUSSION

It is likely that the CYP2D6 isoenzyme is not responsible for a high proportion of thiothixene clearance, but one cannot exclude the possibility that a longer paroxetine pretreatment might have caused some inhibition of thiothixene clearance.

Cryosurgery of prostate cancer. Use of adjuvant hormonal therapy and temperature monitoring--A one year follow-up

OBJECTIVE

To determine the clinical outcomes at one year of Stages T2-T3 prostate cancer by cryosurgery utilizing pretreatment with total androgen ablation therapy and temperature monitoring to control the freezing process. Study Group To date, 347 patients have had 356 cryosurgical procedures, 280 have reached one year post treatment. Of these 131 had re-evaluation with prostatic biopsy and serum PSA.

METHODS

Transrectal ultrasound (TRUS) measurement of tumor size and biopsy of extraprostatic space was used to stage patients into two main groups: confined (66.6%) versus nonconfined (19.3%). Radiation failures (14.1%) formed a separate group. Failure rates for the 131 men include all cancer diagnosed during the one year period following cryosurgery.

RESULTS

The one year failure rate for the study group was 19.8% (26/131). For stages T2a, T2h C, T3 and radiation failures, the rates of positive biopsies were 13.9%, 12.9%, 33.3% and 35%, respectively. For those with local control of cancer (negative biopsy), 80% had prostate specific antigen (PSA) levels of < 0.5 ng/ml. The statistical variables for persistent cancer with prostate specific antigen > 0.5 ng/ml were: sensitivity of 66.7%, PPV of 16.7%, NPV of 98% and specificity of 83.7%. A statistically significant difference exist between stages T2 vs T3 and radiation failures (p = < 0.5). Major complications of rectal fistula and total incontinence for previously non-treated cancer versus radiation failures were 0.33% and 8.7% respectively, a 26 times greater risk.

CONCLUSION

Results of cryosurgery for all stages of prostate cancer at one year are encouraging, being 80% free of disease (biopsy and prostate specific antigen). The morbidity of the previously non-treated cancers from this procedure for us was minimal with high patient acceptance. For radiation failures a local control rate of 65% was achieved. However, early in our experience significant morbidity did occur and our enthusiasm for attempted salvage was initially tempered.

Genotoxicity testing of two red dyes in the somatic and germ line cells of Drosophila

Two red dyes, rhodamine B and amaranth, were tested for their genotoxic effects in the somatic (wing primordia) and germ line cells of Drosophila melanogaster following the wing spot and the sex-linked recessive lethal tests. Second- and third-instar larvae, carrying suitable genetic markers, were subjected to chronic exposure to different concentrations of the test dyes. The results indicate that rhodamine is genotoxic in both somatic and germ line cells and amaranth is non-genotoxic.

Genotoxicity of 2,4-dichlorophenoxyacetic acid tested in somatic and germ-line cells of Drosophila

The genotoxic potential of 2,4-dichlorophenoxyacetic acid, a commonly used chlorophenoxy herbicide, was tested in Drosophila somatic and germ-line cells following the protocols of the wing spot test and the sex-linked recessive lethal test. In the wing spot test second- and third-instar larvae, carrying genetic markers mwh and flr3, were exposed to different concentrations of the herbicide so that induced genetic changes would be phenotypically expressed as mosaic spots on the wings of eclosing adults. The Basc (Muller-5) standard technique but with larval exposure was followed for the sex-linked recessive lethal test. The results obtained indicate that the test compound is genotoxic both in the somatic and germ-line cells of Drosophila.

Expression of recombinant human plasminogen in mammalian cells is augmented by suppression of plasmin activity

We present evidence that over-expression of human plasminogen, the precursor to the serine protease plasmin, can be cytotoxic to mammalian cells. When an expression vector containing plasminogen cDNA is transfected into baby hamster kidney cells, the number of drug-resistant colonies as well as the levels of plasminogen secreted by those colonies is lower than observed in similar transfections of other protease precursor genes. The recombinant plasminogen accumulates intracellularly as degraded NH2-terminal fragments. In contrast, a mutant of plasminogen that produces inactive plasmin (active site Ser740 changed to Ala) is synthesized by these cells as a full-length plasminogen molecule, and the colony numbers and expression levels are normal. Thus, the generation of plasmin activity is responsible for the cytotoxic phenomena and the degradation associated with plasminogen expression. In addition, experiments using a plasminogen mutant that cannot be activated to plasmin (activation cleavage site Arg560 to Gly) or using coexpression of antisense urokinase RNA indicate that an endogenous plasminogen activator is responsible for converting newly synthesized plasminogen to plasmin. Finally, coexpression of plasminogen with alpha 2-plasmin inhibitor, a serpin which is the physiologic inhibitor of plasmin, prevents the toxic effects of intracellular plasmin activity and allows the synthesis and secretion of native human plasminogen.

Stereotactic brain biopsy in the diagnosis of malignant lymphoma

Fifteen patients with cerebral involvement by malignant non-Hodgkin's lymphoma were identified, among more than 200 patients who underwent stereotactic biopsy at The Johns Hopkins Hospital. All but one of these cases were diagnosed accurately by the stereotactic biopsy procedure. In 12 of 14 patients, the material was adequate to classify the lymphoma according to the Working Formulation. Because all but one of the lesions were intermediate or high-grade neoplasms, a diagnosis of lymphoma was often possible by conventional light microscopic examination alone. Monotypic light chain expression was demonstrated by immunohistochemical techniques in six patients, and positivity for B-cell markers was observed in an additional case. In one instance, two stereotactic biopsy specimens were interpreted as being suggestive of lymphoma, but necrosis and inflammation prevented a definitive diagnosis. Nine patients had no known risk factors for cerebral lymphoma, and the diagnosis often was unsuspected clinically.

Endoproteolytic processing of the human protein C precursor by the yeast Kex2 endopeptidase coexpressed in mammalian cells

The human protein C precursor undergoes extensive co- and posttranslational modification during its biosynthesis in the liver. These modifications include glycosylation, gamma-carboxylation, and beta-hydroxylation of specific amino acids and endoproteolytic processing to remove the pre- and propeptides as well as the pair of basic amino acids which connect the light and heavy chains in the precursor. Previous studies with a recombinant mammalian expression system have indicated that the endopeptidase in several mammalian cell types which recognizes and cleaves this dibasic site has a substrate specificity for sites which also include a basic amino acid in the -4 position (Foster et al., 1990). Since the human protein C precursor has His154 in the -4 position, it is poorly and incompletely cleaved in BHK and several other mammalian cell lines and also apparently secreted from the liver as a mixed population of mature two-chain and precursor one-chain molecules. In the present study, a mammalian expression system has been used to study the effect of coexpressing the protein C precursor together with the yeast Kex2 endopeptidase which is known to recognize and process dibasic pairs within peptide precursors in yeast. Coexpression of the KEX2 gene resulted in complete conversion of the protein C precursor to the mature two-chain form. Amino-terminal sequencing of the cleavage products has indicated that the cleavage occurs in the correct location and that this site is preferentially recognized by the yeast endopeptidase within the context of the mammalian cell secretory pathway.

Artificial intelligence for medical decision making

Artificial intelligence techniques find extensive applications in medical decision making and other aspects of health care. A number of successful expert systems have been developed in various disciplines of medicine. This paper gives an overview of expert system techniques, describes some practical systems, and discusses the relevance of such systems in clinical diagnosis and management of diseases.

Endoproteolytic processing of the dibasic cleavage site in the human protein C precursor in transfected mammalian cells: effects of sequence alterations on efficiency of cleavage

The human protein C precursor undergoes extensive co- and posttranslational modification during its biosynthesis in the liver. These modifications include glycosylation, gamma-carboxylation and beta-hydroxylation of specific amino acids, and endoproteolytic processing to remove the pre- and propeptides and also to remove the pair of basic amino acids that connect the light and heavy chains in the precursor. Specific molecular signals have been elucidated which direct several of these modifications; however, the mechanism for cleavage and removal of the basic amino acid pair has not been established. In the present study, a recombinant mammalian expression system has been used to study the molecular signals that direct removal of this basic amino acid pair. Mutations were introduced by site-directed mutagenesis either to insert additional basic amino acids or to alter the sequence adjacent to the basic pair by point mutations. The mutant protein precursors were expressed and analyzed for the degree of processing to 2-chain form and also for the location of the cleavage site (by N-terminal sequencing) and subsequent removal of the basic amino acids from the newly formed C terminus of the light chain. These experiments have shown that human protein C can be readily synthesized and secreted in several mammalian cell lines. However, cell lines vary considerably in their capacity to remove the dibasic pair in the protein C precursor and, like the liver, secrete a mixed population of 1-chain and 2-chain forms of the protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Intraoperative CT-guided serial microbiopsy of brain lesions and concomitant use of CT air and angiographic studies

The value of step-by-step confirmation of the location of the brain biopsy probe is demonstrated, using serial CT scanning to confirm the exact source of the sample tissue. Concomitant use of CT angiography and a CT air study makes possible the biopsy of small areas and of areas near major cerebral vessels, as well as of lesions near critical areas like the optic chiasma, basal ganglia, midbrain, and other complex lesions. The pathologist on-line examination of the CT-confirmed serial samples enables the surgeon to obtain the most informative tissue for the ultimate histopathological diagnosis. Our experience with the technique is illustrated by examples of its application in some complex cases.

Propeptide of human protein C is necessary for gamma-carboxylation

Protein C is one of a family of vitamin K dependent proteins, including blood coagulation factors and bone proteins, that contains gamma-carboxyglutamic acid. Sequence analysis of the cDNAs for these proteins has revealed the presence of a prepro leader sequence that contains a pre sequence or hydrophobic signal sequence and a propeptide containing a number of highly conserved amino acids. The pre region is removed from the growing polypeptide chain by signal peptidase, while the pro region is subsequently removed from the protein prior to secretion. In the present study, deletion mutants have been constructed in the propeptide region of the cDNA for human protein C, and the cDNAs were then expressed in mammalian cell culture. These deletions included the removal of 4, 9, 12, 15, 16, or 17 amino acids comprising the carboxyl end of the leader sequence of 42 amino acids. The mutant proteins were then examined by Western blotting, barium citrate adsorption and precipitation, amino acid sequence analysis, and biological activity and compared with the native protein present in normal plasma. These experiments have shown that protein C is readily synthesized in mammalian cell cultures, processed, and secreted as a two-chain molecule with biological activity. Furthermore, the pre portion or signal sequence in human protein C is 18 amino acids in length, and the pro portion of the leader sequence is 24 amino acids in length. Also, during biosynthesis and secretion, the amino-terminal region of the propeptide (residues from about -12 through -17) is important for gamma-carboxylation of protein C, while the present data and those of others indicate that the carboxyl-terminal portion of the propeptide (residues -1 through -4) is important for the removal of the pro leader sequence by proteolytic processing.

Sequence of the Ampullariella sp. strain 3876 gene coding for xylose isomerase

The nucleotide sequence of the gene coding for xylose isomerase from Ampullariella sp. strain 3876, a gram-positive bacterium, has been determined. A clone of a fragment of strain 3876 DNA coding for a xylose isomerase activity was identified by its ability to complement a xylose isomerase-defective Escherichia coli strain. One such complementation positive fragment, 2,922 nucleotides in length, was sequenced in its entirety. There are two open reading frames 1,182 and 1,242 nucleotides in length, on opposite strands of this fragment, each of which could code for a protein the expected size of xylose isomerase. The 1,182-nucleotide open reading frame was identified as the coding sequence for the protein from the sequence analysis of the amino-terminal region and selected internal peptides. The gene initiates with GTG and has a high guanine and cytosine content (70%) and an exceptionally strong preference (97%) for guanine or cytosine in the third position of the codons. The gene codes for a 43,210-dalton polypeptide composed of 393 amino acids. The xylose isomerase from Ampullariella sp. strain 3876 is similar in size to other bacterial xylose isomerases and has limited amino acid sequence homology to the available sequences from E. coli, Bacillus subtilis, and Streptomyces violaceus-ruber. In all cases yet studied, the bacterial gene for xylulose kinase is downstream from the gene for xylose isomerase. We present evidence suggesting that in Ampullariella sp. strain 3876 these genes are similarly arranged.