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Biomedical subjects

M Desai

Publications and source records attributed to M Desai.

At least 109 records · Page 6Linked to original sources
PubMed1996

Adhesion to enamel of light-cured poly-acid dental materials.

The purpose of this study was to determine the tensile bond strengths of a resin-modified glass ionomer cement and a poly-acid modified resin composite to enamel. Three different enamel surface preparations (unetched enamel; enamel treated with 10 per cent polyacrylic acid, enamel etched with 35 per cent phosphoric acid), were used. On etched enamel, the glass ionomer cement (15.0 MPa) and the resin composite (14.3 MPa) had significantly higher bond strengths than the other groups tested, but were not significantly different from each other. In the acid treated groups, cohesive failure within the material occurred in all specimens, while in the other groups, all specimens failed adhesively. Further investigation is required to test the clinical efficacy of these restorative materials.

Acid Etching, Dental↗
PubMed1996

Cervical smears--an opportunity for disinvestment?

BACKGROUND: The National Cervical Screening Programme was introduced to increase population coverage while reducing the overscreening of women at low risk. AIM: To describe the frequency with which cervical smears are unnecessarily repeated within the prescribed screening interval. METHOD: All cervical smears taken in a primary care setting in Manchester from women aged 20-64, during 1988-92, were identified. A smear was considered unscheduled if it was taken within 30 months of a preceding smear and if there was no clinical indication or laboratory recommendation for an early repeat smear. RESULTS: A total of 100 134 smears were identified from 85 594 women attending 130 general practices and 40 NHS community clinics; 12 633 women subsequently had 14 702 unscheduled smears; 50% of the unscheduled smears were taken by 18% of the general practices and 8% of the NHS community clinics. CONCLUSION: If they are replicated elsewhere, these findings suggest a substantial disinvestment opportunity.

Adult↗
PubMed1995

Clinical benefit from nebulized human recombinant DNase in Kartagener's syndrome.

Nebulized recombinant human DNase (rhDNase) reduces sputum viscosity, improves pulmonary function, and results in a small reduction in acute respiratory exacerbations requiring intravenous antibiotics in many patients with cystic fibrosis (CF). rhDNase is now recommended for use in CF patients with moderately severe suppurative lung disease. A 14-year-old girl with suppurative lung disease [forced expiratory volume in 1 second (FEV1) 69% and forced vital capacity (FVC) 81% predicted] secondary to Kartagener's syndrome and severe gastroesophageal reflux had worsening spirometry together with intractable gastrointestinal symptoms over the previous 18 months despite conventional treatment. She was, therefore, started on 2.5 mg rhDNase once daily. Her cough lessened and the volume of sputum decreased within 72 hours of commencement of treatment; this improvement was strongly associated with a dramatic reduction in gastrointestinal symptoms. Spirometry after 4 weeks of treatment demonstrated a 20% improvement in FEV1 and a 13% improvement in FVC. These improvements have been maintained after 4 months of rhDNase therapy. The use of rhDNase should be considered in patients with Kartagener's syndrome and a multicenter trial may be justified.

Administration, Inhalation↗
PubMed1995

Histomorphometric and biochemical characterization of bone following acute severe burns in children.

Severe burns in adults is associated with an uncoupling of normal remodeling, low bone formation without reduced resorption. The risk of osteopenia that may occur under such circumstances is heightened by our detection in a cross-sectional study of low bone mass in severely burned children. We report here the acute histomorphometric and biochemical response of bone to severe burn injury, as well as bone mass in severely burned children. We enrolled 24 patients ages 5.8 to 17.5 years following burns of 63 +/- 16% (SD) body surface area. Serum and urine were collected weekly until iliac crest bone biopsy was obtained 26 +/- 10 days postburn. Seventeen of 18 patients, including 5 patients receiving growth hormone treatment to accelerate wound healing, failed to take up doxycycline in trabecular bone, and had no detectable osteoblasts at the osteoid seam, while eroded surface was normal and osteoblasts were documented by staining. Thus, bone formation was virtually absent. There was an eightfold elevation in urinary free cortisol excretion and high serum levels of acute phase reactants and interleukin-1 beta and -6. Biochemical markers of bone formation, osteocalcin, and type I procollagen propeptide were low, as were resorptive markers urinary pyridinoline and deoxypyridinoline. However, there was no correlation with resorptive surface. Mean age-related z-score for bone mass was -1.06 +/- 1.05, 40 days postburn. Immobilization and endogenous corticosteroid production may be the main factors responsible for acutely reduced bone formation while inflammatory cytokines may mediate resorption.

Absorptiometry, Photon↗
PubMed1995

Molecular subtyping of prevalent M serotypes of Streptococcus pyogenes causing invasive disease.

Reproducible methodologies and a scheme for high-resolution genotyping of Streptococcus pyogenes were defined with respect to a study of six predominant M serotypes causing invasive group A streptococcal disease in the United Kingdom. Serotype reference strains were compared with nine clinical isolates of each serotype from patients with diseases such as pneumonia, puerperal sepsis, toxic shock-like-syndrome, cellulitis, or necrotizing fasciitis. Four enzymes were evaluated for their discriminatory power in 16S rRNA gene-specific ribotyping. Discriminatory power was greatest with EcoRI, which generated serotype-specific ribotypes, and with SacI, which could subdivide strains of the same M serotype. Twenty-five combined ribotypes were found among the 60 strains, and the indices of discriminatory power (D values) of this method varied from 0.51 within serotype M1 to 0.98 within strains of serotype M5. Macrorestriction with the rarely cutting endonuclease SmaI and pulsed-field gel electrophoresis gave D values varying from 0.37 within serotype M1 to the maximal 1.0 within serotype M5. Comparison of macrorestriction profiles revealed various degrees of genetic heterogeneity within M serotypes. Strains of M1, M3, M6, and M11 exhibited clonally related macrorestriction profiles, while those of R28 and M5 strains were consistent with polyphyletic origin.

Antigens, Bacterial↗
PubMed1994

Effect of temperature and retention time on biomethanation of cheese whey-poultry waste-cattle dung.

Various conditions, such as temperature, total solid content, cattle dung-poultry waste-cheese whey ratio, retention time and stirring, were optimized with an ultimate aim of improving anaerobic digestion. Maximum gas production (2.2 litres litre(-1) of digester day(-1)) with enriched methane content (62% CH(4)) was found with a retention time of 10 days, having a loading rate of 6.0 g total solid litre(-1) of digester day(-1) at 40 degrees C, and total solid of 6% (w/v) using a mixture of cattle dung, poultry waste and cheese whey in the ratio of 2:1:3 (w/w).

Journal Article↗
PubMed1994

Anaerobic digestion of a mixture of cheese whey, poultry waste and cattle dung: a study of the use of adsorbents to improve digester performance.

This paper-describes the results of a study aimed at improving the efficiency of anaerobic digestion of a mixture of cattle dung, poultry waste and cheese whey at a ratio of 2 : 1 : 3 (w/w on dry weight basis) in terms of total gas production, methane content and process stability by adding various adsorbents. The adsorbents appeared to improve the digester performance, for example about a two-fold enhancement in total gas production with 17% enriched methane content were achieved with the addition of 4 g litre(-1) of silica gel.

Journal Article↗
PubMed1994

Flagellin gene profiling of Helicobacter pylori infecting symptomatic and asymptomatic individuals.

Diversity within and around the flagellin (fla) A gene of Helicobacter pylori was studied by polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) analysis and genomic Southern blot hybridization profiling. Four distinct pattern types were identified by DdeI restriction analysis of the 1.5-kb flaA amplicon of 55 strains. Most strains (73%) had the same flaA RFLP type, but subtypic variation was evident in some strains. No consistent associations were observed for selected strain subsets between the DdeI flaA profiles and phenotype (motility and cytotoxicity), urease gene profile or patient symptomatology. A subset of seven (F-1 profile) and four (F-2 profile) strains with identical HindIII digest patterns provided further evidence that the flaA gene was relatively highly conserved within H. pylori. By contrast, the flaA gene blot hybridization profiles were more diverse and consistent with greater variation at restriction sites in adjacent regions of the genome. We conclude that analyses of polymorphisms within the flaA gene provide limited discrimination between strains of H. pylori. The flaA genomic blot profiles offer greater potential for molecular typing purposes, although no associations with other pathogenicity factors or disease symptoms could be deduced.

Blotting, Southern↗
PubMed1994

Molecular typing of Helicobacter pylori isolates from asymptomatic, ulcer and gastritis patients by urease gene polymorphism.

The gastric-adapted bacterium Helicobacter pylori plays an important role in gastritis and ulcer disease, but no phenotypic typing scheme presently exists for this organism. With a view to the development of genotypic typing, we have compared isolates of H. pylori from gastritis or ulcer patients with those from subjects exhibiting no disease. Variation was analysed at the urease genes, ureA and ureCD, by employing PCR-generated probes in genomic Southern blot hybridizations. Whilst ureA restriction fragments provided a fourfold subgrouping of strains, ureCD fragments were considerably more discriminatory. Twenty-four combined ureACD profiles were generated with Hind III, subdividing the 64 strains into 11 types and 13 single profiles. The most prevalent profile (UI) was found in 33% of strains, almost all from gastritis or ulcer patients. On the other hand strains isolated from asymptomatic individuals had the most diverse ureACD profiles. A key finding from this set of isolates was that strains of H. pylori associated with general gastroduodenal disease were genetically more homogeneous than strains carried by people without disease symptoms.

Bacterial Typing Techniques↗
PubMed1993

Differentiation between isolates of Helicobacter pylori by PCR-RFLP analysis of urease A and B genes and comparison with ribosomal RNA gene patterns.

Genetic diversity amongst 21 human gastric isolates of Helicobacter pylori was investigated by polymerase chain reaction amplification and HaeIII digest (restriction fragment length polymorphism) analysis of an internal 2.4-kb segment of the urease A and urease B genes. H. pylori from 11 independent individuals yielded nine distinct restriction fragment patterns but only one pattern was common to H. pylori from two individuals. By contrast, multiple isolate sets of H. pylori from two patients each had common urease gene patterns. Most strains with the same urease gene patterns were distinguishable in their ribosomal RNA gene patterns. The study demonstrated diversity amongst H. pylori and established that PCR analysis of urease genes provided a novel method of identifying isolates. The profiles were reproducible and convenient to obtain and analyse, and were almost as discriminatory as HaeIII ribopatterns.

Bacterial Typing Techniques↗
PubMed1993

Comparisons between degree of histological gastritis and DNA fingerprints, cytotoxicity and adhesivity of Helicobacter pylori from different gastric sites.

Thirty-six isolates of H. pylori from up to three gastric biopsy sites (antrum, corpus and fundus) from 13 patients in Italy with different degrees of histological gastritis were investigated. All strains were tested for motility, cytotoxicity and degree of adhesion, and were typed by analysis of ribosomal RNA gene patterns (ribopatterns). Seventeen different DNA types (ribotypes) were identified, with each patient possessing H. pylori of one or more unique types. Only two patients had identical H. pylori at three sites. Most patients had H. pylori with different ribotypes or subtypes, but nine strains were not typable. Five patients had the same strain colonizing two of the three sites and atypical strains were mostly from the antrum. A complex pattern of H. pylori colonization in the stomach of some individuals was evident and suggested multiple sources of infection. No consistent associations were detected between degree of gastritis and adherence, cytotoxicity and motility but a 2.56Kb rRNA gene fragment that had a higher frequency in strains associated with severe gastritis than mild gastritis, may provide a useful molecular marker for future pathogenicity studies.

Bacterial Adhesion↗
PubMed1993

Biotype and molecular fingerprints of metronidazole-resistant strains of Helicobacter pylori from antral gastric mucosa.

Biotypes, ribosomal RNA gene restriction patterns (ribopatterns), whole-cell protein patterns and plasmid profiles of paired Helicobacter pylori isolates from 17 patients were examined. Each pair comprised a pre- and a post-treatment isolate; nine of the 17 post-treatment isolates were obtained after treatment with tripotassium dicitrate bismuthate (De-Nol) and metronidazole. All strains of H. pylori had identical biotypes, but exhibited diversity between pairs in their molecular fingerprints. Each of the 17 strain pairs had unique ribopatterns; the pre- and post-treatment isolates in most pairs (16 of 17) were similar or identical, irrespective of metronidazole susceptibility. DNA subtype variants were detected in three patient sets. Although nine post-treatment isolates had acquired resistance to metronidazole, most (six of nine) resembled the pre-treatment isolates in their ribopattern, protein and plasmid profiles. No significant correlation was observed between metronidazole resistance and plasmid content in these H. pylori isolates. Emergence of post-treatment metronidazole-resistant isolates of H. pylori was associated only rarely with colonisation by a novel strain or acquisition of a plasmid and, in most patients, probably resulted from spontaneous emergence of resistance in the original infecting strain.

Bacterial Proteins↗
PubMed1993

Genetic diversity of Helicobacter pylori indexed with respect to clinical symptomatology, using a 16S rRNA and a species-specific DNA probe.

DNA probes are described which identify group and fingerprint strains of the human gastric pathogen Helicobacter pylori, on the basis of well-defined band homologies. A 544 bp internal fragment of the 16S ribosomal RNA gene was generated by polymerase chain reaction (PCR) with primers derived from the Escherichia coli rRNA gene sequence. In genomic Southern blots this probe detected restriction site variation around these loci, generating simple but strain-specific molecular fingerprints. A small conserved chromosomal fragment of 1.2 kbp, Hps, species-specific for H. pylori, was obtained by cloning random HindIII fragments into pUC19. It was useful for dot-blot identification, and also separated isolates into one major and two minor groups. When results for these two probes were combined, a baseline characterization of genotype was obtained. A band-matching database of molecular fingerprints for the type strain and 63 clinical isolates of H. pylori from asymptomatic, ulcer and gastritis contexts is presented. No significant association between the genotypes at this level of definition and the associated clinical symptomatology of the isolates was detected.

DNA Primers↗