Search PubMed⌕ Search

Biomedical subjects

G H Davis

Publications and source records attributed to G H Davis.

At least 55 records · Page 3Linked to original sources
PubMed1982

Polysaccharase activity in Streptococcus agalactiae (group B streptococci).

Of 300 recently isolated strains of Streptococcus agalactiae from human sources, 97% degraded starch. Representative strains also degraded glycogen, pullulan, amylopectin and amylose. The polysaccharase activity is easily detected by clearing around growth on Columbia agar base medium. The activity is weaker than that of some S. pyogenes strains, and it does not appear to produce fermentable products but is inhibited by the presence of easily used sugars.

Polysaccharide-Lyases↗
PubMed1982

Enzymatic profile of Pseudomonas maltophilia.

An enzymatic profile of 20 strains of Pseudomonas maltophilia was undertaken with conventional plate tests, API ZYM, and 4-methylumbelliferyl-conjugated substrates. All strains produced DNase, RNase, arbutinase, esterases and lipases, mucinase, acid and alkaline phosphatases, alkaline pyrophosphate diesterase, phosphoamidase, beta-glucosidase, leucine arylamidase, and acetatase and were hemolytic for horse, sheep, and rabbit blood. The majority of strains produced chitinase, hyaluronidase, albuminase, valine arylamidase, trypsin, alpha- and beta-glucosidases, and N-acetyl-beta-glucosaminidase. API ZYM and 4-methylumbelliferyl-conjugated substrate assays are rapid, simple, specific, and sensitive and may be useful as diagnostic aids in the identification of P. maltophilia and other pseudomonads.

Deoxyribonucleases↗
PubMed1980

The distribution of group B streptococcal serotypes among isolates obtained in three Australian cities.

One hundred and sixty three isolates of group B streptococci from human carrier and disease conditions in Brisbane, Melbourne and Adelaide were serotyped by the Lancefield capillary precipitin test, coagglutination and microimmunodiffusion. Serotypes I and III were most common; serotype III appeared to occur uniformly but serotype Ia varied in distribution. No significant difference was found in serotype distribution among isolates from pregnant and non-pregnant women, or rectal and vaginal swabs; however, type Ia was found to occur significantly more often as an infectious agent than as a commensal (P less than 0.01).

Australia↗
PubMed1980

Changes in the vaginal and rectal carriage of group B streptococci during pregnancy.

The group B streptococcus carrier status of pregnant women appears to be relatively unstable. By using multiple low vaginal and rectal samples cultured on 2 or more media, an overall carrier rate of 38% was found in 187 women. Sequential samples commonly showed changes in the nature of the carrier status with time. More carriers were detected late in pregnancy; women giving negative results early in pregnancy often produced positive cultures later and there was a significant tendency towards rectal positivity.

Female↗
PubMed1979

A comparison of four methods for the serotyping of group B streptococci.

Group B streptococci are implicated in a wide range of clinical conditions in human adults and neonates. The Group is subdivided into five serotypes Ia, Ib, Ic, II and III, which are differentiated on the basis of capsular polysaccharides. In the interests of epidemiology and efficiency a cheap, rapid method which is easily interpreted would be advantageous. In this study four methods of serotyping, namely, counter-immunoelectrophoresis (CIEP), microimmunodiffusion (MID), coagglutination (COA), and the Lancefield capillary precipitin (CP) test were compared in terms of ease of operation and interpretation, accuracy and rapidity. Todd Hewitt Broth (THB) cultures and acid extracts of the group B streptococcal strains were used as antigens for these methods. It was concluded that COA using THB cultures allows cheap and rapid screening for presumptive serotyping, having a 93-96% correlation with the CP test. MID gives an accurate (100% correlation with the CP test) and unambiguous confirmatory diagnosis of serotype.

Agglutination Tests↗
PubMed1975

Efficacy of 17alpha-hydroxyprogesterone caproate in the prevention of premature labor.

We conducted a double-blind study to determine the efficacy of 17alpha-hydroxyprogesterone caproate in preventing premature delivery in 43 high-risk patients. Premature delivery did not occur in 18 patients receiving the progestational agent, whereas 41 per cent of the 22 receiving the palcebo had premature delivery (P less than 0.01). The mean duration of pregnancy and the mean birth weight in the former group (38.6 weeks +/- 1.6 S.D., and 2836 g +/- 412 S.D.) were both significantly greater (P less than 0.025) than that in the latter (35.2 weeks +/- 6.7 S.D.; 2361 g +/- 1085 S.D.). The perinatal mortality rate in the group given the progestational agent (O per cent) was significantly less than that observed in the placebo group (27 per cent) (P less than 0.05). Although there were no complications attributable to the progestational drug, the study population was too small for assessment of immediate or long term safety. However, the results indicate a possible obstetric use for this drug.

Adult↗
PubMed1967

Sensitivity to six mycobacterial antigens in young Nigerian adults.

A preliminary survey of sensitivity to six mycobacterial antigens in young Nigerian adults resident in Lagos is reported. The results support the contention that non-specific tuberculin reactions in Nigeria are largely the result of sensitization of the population by atypical mycobacteria and that the bacteria most active in this respect are of Runyon's Groups II and III (scotochromogens and unpigmented). Cross-reactions with antigens of atypical mycobacteria in populations of different tuberculin status are analysed in some detail.

Adolescent↗