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Biomedical subjects

D R Martin

Publications and source records attributed to D R Martin.

At least 109 records · Page 6Linked to original sources
PubMed1984

M-associated protein antibodies in patients with rheumatic fever.

Sequential serum samples obtained from 50 rheumatic fever subjects and from control individuals matched for time, age and geographical location were tested for antibodies against the M-associated protein antigens, MAP I and MAP II. Antibody titres were determined by the complement fixation test with a partially-purified extract of Streptococcus pyogenes serotype M30 as the MAP I antigen and an acid extract of serotype M48 as the MAP II antigen. Titres of MAP I antibody exceeded those of MAP II antibody in all but six rheumatic fever subjects. Anti-MAP I titres in excess of 40 were significantly more common in rheumatic fever subjects than in matched controls (p less than 0.001) or matched subjects with a diagnosis of acute post-streptococcal glomerulonephritis (p less than 0.01). Peak MAP I titres were present at the time of admission to hospital in the sera of 40 of the 50 rheumatic fever subjects. In the remainder peak titres occurred within 10 days. Antibody titres were maintained for a mean of 10.3 weeks before declining. Changes in MAP antibody titres were independent of changes in antistreptolysin O and anti-DNAase B titres. Normal children aged between 6 and 15 had higher MAP antibody titres than 2-5-year-old children. Rheumatic fever subjects had significantly higher mean titres of MAP I antibody than matched controls in each age group.

Acute Disease↗
PubMed1984

Human and bovine group B streptococci: two distinct populations.

Group B streptococci (Streptococcus agalactiae) from humans and animals were compared for cultural, biochemical, serological and bacteriocin sensitivity properties. Each isolate possessed the group B carbohydrate antigen, hydrolysed hippurate, and was CAMP test positive. Most human isolates were characterized as bacitracin resistant, pigment producing, haemolytic, and salicin but not lactose utilizing. In contrast bovine isolates were usually bacitracin sensitive, non-pigment producing, non-haemolytic, salicin and lactose utilizing. Isolates from other animals behaved similarly to those from humans. Whereas human isolates belonged to a variety of serotypes and were uniformly sensitive to bacteriocins, bovine isolates showed varying sensitivity to bacteriocins and most belonged to serotype II or were non-typable. We believe these results support the belief that Strep. agalactiae from humans and cattle are separate populations sharing the same group B carbohydrate antigen.

Animals↗
PubMed1984

Complement-fixing islet cell antibodies in the spontaneously diabetic BB rat.

Fourteen rats of the spontaneously diabetic BB line were bled from the retroorbital sinus approximately every 10 days. Sera taken from an early age up to 20 days after the onset of overt diabetes were assayed for complement-fixing antibodies against antigens of the surface of islet cells (CFA). Dispersed islet cells from normal Wistar rats prelabeled with 3H-leucine were used as targets. Target cells in suspension were incubated with heat-inactivated rat sera and then, after washing, exposed to guinea pig complement. Cytolytic "injury" was measured by the percentage of labeled cellular proteins released into the medium. Sera from sequential bleedings from eight normal Wistar rats and three rats from a nondiabetic BB subline were assayed to establish basal control cytolytic activity. The mean response +/- SD obtained with all control sera was 7.7 +/- 1.7%. A response exceeding the mean + 3 SD (12.8%) was considered significantly different from the basal value. Thirteen of the fourteen BB rats developed strongly positive sera. The cytolytic activity preceded the onset of overt diabetes. In several rats CFA appeared 4-8 wk preceding diabetes while in other rats CFA appeared 1-2 wk preceding the manifestation of the disease. These results indicate that CFA may contribute to the destruction of pancreatic islets directly or by attracting mononuclear cells.

Animals↗
PubMed1984

Evaluation of a typing scheme for group A streptococci based upon bacteriocin-like inhibitor production.

A method of typing (P-typing) streptococci according to their production of inhibitory activity against a set of 9 indicator strains has been evaluated. Modifications to a previously described P-typing procedure have been made which improve the reproducibility of the method and also reduce the proportion of untypable strains. The test conditions, particularly medium composition, incubation temperature and aeration were found to be critical determinants of inhibitor production and must be carefully controlled. The use of certain commercial sources of Blood Agar Base and the presence of human blood in the typing medium are requirements for detection of some inhibitors, particularly for P-type 777 strains. The previously "standardized" conditions for P-typing specify incubation of the test strains aerobically at 32 degrees C. However, in order to increase the proportion of typable strains an additional set of cultures should be incubated anaerobically. Anaerobic incubation was found to be essential for the production of bacteriocin-like inhibitors by M-type 49 strains and markedly increased inhibitor production by M-type 4 and M-type 57 strains. Also associated with anaerobic incubation was an increase in the amount of non-specific, acid-mediated inhibition, but this could be eliminated by buffering the typing medium with 0.5% (w/v) calcium carbonate. The epidemiological validity of P-typing was tested in a survey of group A streptococcus carriage in a school and in 9 family groupings. Inhibitor production appeared to be a stable strain marker and the occurrence of some P-type subdivisions within clusters of strains having identical serotype patterns indicates that combined application of serotyping and P-typing may give improved strain discrimination.

Bacteriocins↗
PubMed1983

Streptococci--are they different in New Zealand?

Rheumatic fever and acute glomerulonephritis resulting from group A streptococcal infection are important childhood illnesses in New Zealand particularly in certain geographical areas. A study of streptococcal serotypes occurring in infections during a three year period, May 1979-May 1982, has shown that many serotypes with well documented disease-association occur amongst New Zealand isolates. During the period of study disease-association of specific serotypes was demonstrated. Serotypes unique to New Zealand were not major contributors to disease patterns.

Humans↗
PubMed1982

Streptococcal involvement in childhood acute glomerulonephritis: a review of 20 cases at admission.

Twenty children sequentially admitted to the paediatric ward, Tauranga Hospital, with a diagnosis of acute glomerulonephritis, are reviewed for evidence of recent streptococcal infection as at admission. Sixteen children (80 percent) were shown to have at least one streptococcal antibody titre (ASO and anti-DNase B) elevated above the upper limit of normal for the population. Two children had negligible antibody levels detected. Case histories and/or cultural results provided additional supportive evidence for recent streptococcal infection. Serotypes of recognised nephritogenic potential were isolated from five patients.

Adolescent↗
PubMed1980

Probable association of M type 57 streptococcal skin infection with acute glomerulonephritis in the Tauranga area.

Evidence is presented for the probable association of streptococcal skin infection (M type 57) with six cases of acute glomerulonephritis. M type 57 streptococcus was isolated from skin infections in four of the cases and from skin sores occurring in sibling contacts of the other two. Two of the cases occurred at a time when M type 57 streptococcus predominated in skin lesions of children from the same school. A further two cases of post-streptococcal nephritis with possible involvement of M type 57 are discussed. The superiority of the anti-DNase B test over anti-streptolysin O determination in a situation when streptococcal pyoderma nephritis has occurred is shown.

Acute Disease↗
PubMed1978

Rheumatic fever and streptococci: the Wairoa College study.

The decline in incidence of rheumatic fever seen in many countries is not evident in New Zealand. Wairoa county has the highest hospital admission rate within New Zealand, 232 per 100 000 per year, five times the national average, 43 per 100 000. Studies in Wairoa included a cross-sectional survey of the local secondary school. Throat swabbing yielded 13.6% of subjects positive for beta-haemolytic streptococcus group A. Boys had a higher rate than girls, and girls aged 14 and over had a lower rate than younger girls. Discriminant analysis failed to identify ethnic, social or geographic factors as contributing to positivity. Sibling concordance was not significant. ASO titres were high in comparison with another New Zealand study (Rotorua Lakes). There was an association between high ASO titre and throat swab positive for group A and group C streptococci. The prevalence of definite rheumatic fever and rheumatic heart disease was established as 11/715 (1.5%). A wide range of residential geographic, climatic and socioeconomic factors failed to discriminate between cases and noncases. Ethnicity alone was a significant discriminator, the cases being more Maori than noncases.

Adolescent↗
PubMed1977

Delayed culture of group-A streptococci: an evaluation of variables in methods of examining throat swabs.

We studied the effects on the frequency of isolation of group-A streptococci from throat swabs of school children on three varibles: (1) plating the cultures within 4 h of collecting the swabs or after storage for 4 days at room temperature; (2) using a plain or a serum-coated cotton swab; and (3) including silica gel in the swab tube or omitting this. Under the conditions of our experiment, only delayed plating of the swab gave a statistically significant advantage. When the delayed-isolation technique was used, neither the swab type nor the presence or absence of silica gel significantly influenced the result. The least advantageous combination of variables was: plating within 4 h, a plain swab, and the absence of silica gel.

Adolescent↗
PubMed1976

Chemical nature and sequence of alamethicin.

An n.m.r. spectroscopy study of pure alamethicin shows it to be a linear polypeptide of 19 residues. The N-terminus is blocked by an acetyl group, and the eighteenth residue, glutamic acid, is linked by an amide bond on its side chain to phenylalaninol (Fig. 6). The new formula is confirmed by a comparison between pure chemical compounds and the products of partial hydrolysis.

Alamethicin↗