PubMed Health⌕ Search

Biomedical subjects

M A Curtis

Publications and source records attributed to M A Curtis.

At least 91 records · Page 5Linked to original sources
PubMed1991

Specific antibody responses to subgingival plaque bacteria as aids to the diagnosis and prognosis of destructive periodontitis.

We have reviewed the recent literature on the humoral immune responses to a variety of subgingival plaque bacterial species in patients with destructive periodontal diseases. We do not feel that the information presently available on the specific antibody responses to proposed pathogens such as Bacteroides gingivalis and Actinobacillus actinomycetemcomitans allows antibody responses to be diagnostic. All control subjects without periodontal destruction have antibodies to candidate pathogens but the generally higher levels in patients are not sufficiently elevated to be diagnostic. Nor can they be used to predict the initiation of disease or the onset of new episodes of destruction where disease had previously occurred. Successful treatment of patients may lead to lower levels of antibodies to some organisms, including possible pathogens, and thus support a given species in the aetiopathogenesis of disease. It appears that unsuccessful treatment may be accompanied by continuing high antibody levels to some organisms and further studies may enable this observation to be used to monitor therapy. There is some evidence from serological studies that each destructive episode may be induced by a different bacterial species or consortium. The start of studies using single antigens and the techniques of molecular biology will provide not only antibody-based diagnostic methods but also allow us to determine which bacterial antigens are virulence factors and thus the role of the antibody responses, whether protective or damaging, in the periodontal diseases.

Actinobacillus↗
PubMed1991

Paternal origin of the chromosomal deletion resulting in Wolf-Hirschhorn syndrome.

DNA samples were obtained from children with Wolf-Hirschhorn syndrome and their parents to assist with gene mapping studies of 4p16.3 (the region known to contain the Huntington's disease gene). A panel of seven families was studied, using polymorphic DNA markers, to determine the parental origin of the chromosome abnormality resulting in Wolf-Hirschhorn syndrome. All seven cases were the result of de novo deletions or rearrangements of 4p and in each case the abnormality arose on the paternal chromosome. Analysis of the 3' hypervariable regions of the alpha globin and mucin loci indicated that non-paternity was unlikely to be an explanation for these results. A paternal age effect was not observed. The possibilities of an environmental influence or genetic imprinting require further consideration. This report extends information regarding the preponderance of the paternal origin of de novo structural deletion syndromes.

Adult↗
PubMed1991

Diphyllobothriasis: fish tapeworm disease in the circumpolar north.

Although fish tapeworm infections in arctic and subarctic residents are often attributed to the cestode Diphyllobothrium latum, other Diphyllobothrium species are frequently responsible. D. dendriticum, for example, occurs throughout the circumpolar area at high latitudes beyond the range of D. latum. Several additional species are also implicated in human infections in northern communities bordering the Pacific: D. ursi from northern Canada and Alaska, D. dalliae from Alaska and Siberia, and D. klebanovskii from Siberia. Routine diagnosis of diphyllobothriasis by coprology does not allow designation of the Diphyllobothrium species involved as their eggs cannot be differentiated and identification of the proglottids from adult worms requires a taxonomic specialist. On the other hand, relevant information on the Diphyllobothrium species most likely to infect the inhabitants of a particular region can be derived from a knowledge of the fish consumed. Larvae of D. dendriticum occur predominantly in salmonid fishes (e.g. arctic char, salmon, trout, whitefish), and this parasite has never been found in pike and perch, the usual intermediate hosts of D. latum. Conversely, D. latum is rarely found in salmonids. D. ursi and D. klebanovskii predominantly occur in Pacific salmon, and D. dalliae in Alaskan blackfish. Species other than D. latum probably constitute transitory intestinal infections in humans, usually lasting for only a few months. Although many carriers are asymptomatic, overt clinical manifestations of diphyllobothriasis can include diarrhea, epigastric pain, nausea and vomiting. There are no reports of anaemia associated with any of the northern species except D. latum. Effective control for diphyllobothriasis originating from D. latum has been achieved in many areas by a combination of selective drug therapy and improved sewage treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Responses of the fish ectoparasite Salmincola edwardsii (Copepoda) to stimulation, and their implication for host-finding.

The short-lived infective copepodid stages of the copepod Salmincola edwardsii, ectoparasitic on brook trout, Salvelinus fontinalis, are under strong selective pressure to evolve efficient host-finding mechanisms. In laboratory experiments, we quantified the effects of visual and mechanical stimulation on the activity of the copepodids. We found that shadows passing above the copepodids and shock waves passing through the water generated marked increases in the rate and length of upward swimming bursts, which resulted in more time spent suspended in the water column and greater distances travelled. However, we found no strong evidence for a relationship between the magnitude of the copepodids' response and the intensity of stimulation. Although these responses are not host-specific, they allow the parasites to conserve their limited energy stores by increasing their host-finding activity only when potential hosts are nearby.

Analysis of Variance↗
PubMed1990

Haemin inhibits the trypsin-like enzyme activity of Porphyromonas gingivalis W83.

The effect of haemin and related porphyrins on the activity of the trypsin-like enzyme activity in cell sonicates of Porphyromonas gingivalis was examined using a spectrophotometric assay and by following the degradation of human IgG. Haemin was inhibitory in both assay systems and the effect was shown to be reversible. The high concentration of haemin accumulated by P. gingivalis may protect the organism against autodegradative effects of the trypsin-like protease.

Arginine↗
PubMed1990

Detection of high-risk groups and individuals for periodontal diseases: laboratory markers based on the microbiological analysis of subgingival plaque.

Periodontal microbiology is reviewed with regard to the potential of certain characteristics to serve as markers of high risk groups or individuals for periodontal diseases. The generally accepted associations between particular organisms and the various periodontal diseases are discussed. The usefulness of various clinical study designs is reviewed. The ecology of the subgingival plaque microflora is discussed and a number of suggestions for future research are made. We have concluded that there is no monospecific aetiology to any of the various periodontal conditions. Nevertheless, we give particular attention to the role of the black-pigmented bacteroides based upon our belief that they, and Bacteroides gingivalis in particular, are fundamental to our understanding of the biology of periodontal diseases in humans and other animals. Consequently, the contribution of its various virulence factors and their potential as markers of disease susceptibility and activity is addressed.

Bacterial Physiological Phenomena↗
PubMed1990

The role of histopathology in the diagnosis and prognosis of periodontal diseases.

The histological evaluation of surgical biopsies from affected tissues is a standard way of assessing pathological change and determining treatment in many diseases. In most forms of periodontal disease, however, this approach finds limited application. Here, we review what uses the histopathological approach has in the study and evaluation of the periodontal diseases. Current understanding of the changes in epithelial anatomy during pocket formation, the cellular composition and dynamics of the inflammatory infiltrate and the mechanisms of bone resorption and repair are reviewed from the perspective of the information available from microscopical investigation, including the uses and potential application of modern immunocytochemical methods to these questions. The usefulness of histological study of biopsy material is reassessed in the light of advances made in immunohistochemical techniques and their application to gingival inflammatory infiltrates and epithelia. Such techniques offer immediately valuable research opportunities with potential for diagnostic applications, noteably the recognition of phases of destructive activity and their differentiation from periods of effective host defence.

Gingiva↗
PubMed1990

Statistical models for data from periodontal research.

Many factors have been hypothesised either to characterise groups and individuals at risk for periodontal disease or to be markers of periodontal breakdown. In order to identify these as associated either with disease status or progression, a statistical association between the factor and a measure of disease will have to be demonstrated. The statistical modelling of data arising from periodontal research presents special problems. These include the large number of measurements made in each subject, the large magnitude of measurement error compared to the changes in attachment level, the analysis of longitudinal studies, the lack of a measure of instantaneous rate of attachment loss and controversies over the nature of the progression of the disease. We consider statistical methods currently available in the light of these difficulties and identify areas in which further research is necessary.

Analysis of Variance↗
PubMed1990

The protein composition of gingival crevicular fluid sampled from male adolescents with no destructive periodontitis: baseline data of a longitudinal study.

Gingival crevicular fluid (GCF) is a promising source for markers of destructive periodontal diseases activity. As the initial stage of a longitudinal study into the characterization of disease markers, GCF sampled from 104 sites in 74 adolescents was examined via sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS/PAGE). In this population, which had varying degrees of gingivitis but little evidence of destructive periodontitis, there was a highly homologous GCF protein profile. The plasma components, albumin, transferrin and IgG, were major constituents of all samples. In addition, a second group of non-plasma derived proteins, with molecular weights 37 kDa, 47 kDa, 57 kDa and 59 kDa, was also commonly detected. The high frequency of occurrence of these components suggests that they may represent products of normal turnover of the periodontal tissues. Analysis of GCF sampled from patients with progressing destructive disease revealed a different SDS/PAGE profile particularly with respect to proteins of non-plasma origin. It is anticipated that the major metabolic changes which accompany the destruction of the tissues during future disease episodes in the adolescent study population will be discernible as alterations to the GCF protein profile.

Adolescent↗
PubMed1990

Treatment of virulent footrot with lincomycin and spectinomycin.

A mixture of lincomycin and spectinomycin was investigated as a treatment for footrot in sheep. In a controlled clinical trial 92.5% of acute and chronic cases of virulent footrot were cured following a single intramuscular injection of a mixture containing 50 mg lincomycin and 100 mg spectinomycin/ml at a dose rate of 1 ml/10 kg bodyweight. No improvement in clinical response was observed in groups of sheep treated on 3 successive days with this dose rate nor in another group treated once at a dose rate 1 ml/3.3 kg bodyweight. Cure effectiveness of each of the 3 treatment groups relative to untreated controls was 89%, 95% and 95%. Efficacy of lincomycin/spectinomycin was compared with that of penicillin/streptomycin in the treatment of footrot on 2 farms in south western New South Wales. Assessments made 14 to 17 d after treatment showed that on one farm all 122 ewes treated with lincomycin/spectinomycin had recovered while 170 of 175 ewes treated with penicillin/streptomycin recovered in the same period. On the second farm 87 of 90 ewes treated with lincomycin/spectinomycin recovered, compared with 184 of 190 sheep in the same flock treated with penicillin/streptomycin. Supportive footbathing did not seem to improve the clinical response in either treatment group and the paring done was sufficient only to establish diagnosis and to remove grossly overgrown horn.

Animals↗
PubMed1989

A method for the refinement of data arising from electrophoresis of biological fluids.

Gingival crevicular fluid (GCF) is being analyzed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS/PAGE) in our laboratory. We wish to characterize the major protein species in GCF and to investigate their association with the progression of disease. Laser densitometry of SDS/PAGE provides estimates of log molecular weight (LMW) and relative abundance for each band in each sample. Our aim was to develop a method for the refinement of these data into clusters which could be treated as distinct protein species, whose relation to disease progression could be assessed. A reproducibility study showed that the estimated LMW would fall within 3% of the true LMW 95% of the time. The method clusters the estimated LMWs of each band in each sample so that clusters form at LMWs which occurred frequently. The data from each band in each sample are thus refined into cluster number and relative abundance. Application of the technique to data from the reproducibility study showed that clusters formed around the individual components in the mixture, with little misclassification. The technique was then applied to two data sets: from SDS/PAGE of 104 GCF samples from 74 adolescents without progressive periodontal disease, and from 2 patients suffering from advanced progressive disease. The clusters appeared accurately to reflect the appearance of the gels, and clear differences were observed between the two data sets. The method will enable changes in the composition of biological fluids to be associated with external factors such as disease status and should be widely applicable.

Adolescent↗
PubMed1989

Detection of high-risk groups and individuals for periodontal diseases: laboratory markers from analysis of gingival crevicular fluid.

Gingival crevicular fluid is regarded as a promising medium for the detection of markers of periodontal diseases activity. The collection protocols are straight forward and non-invasive and can be performed at specific sites of interest in the periodontium. Because the fluid accumulates at the gingival margin, it will contain potential markers derived not only from the host tissues and serum but also the subgingival microbial plaque, and thus an extremely broad range of candidate molecules may be investigated. However, the ability to successfully describe indicators of current disease activity and predictors of future disease is dependent not only upon the choice of the biochemical marker but also on the accurate description of the health status of the sample sites using currently available clinical and radiographic methods. Areas of study which currently show the most promise involve the analysis of host enzyme activities directed against components of the extracellular matrix, the nature of the glycosaminoglycans released into the sulcus and the concentration in gingival crevicular fluid of certain mediators of the inflammatory process, most notably prostaglandin E2.

Disease Susceptibility↗
PubMed1989

Detection of high-risk groups and individuals for periodontal diseases: laboratory markers from analysis of saliva.

The use of saliva as a source of components that may identify subjects at risk of developing destructive periodontitis, or provide markers of disease potential or activity, has been reviewed. It was concluded that bacteria, their constituents or products are unlikely to be rewarding and that host-derived salivary factors such as enzymes cannot identify risk, as deficiency states for these do not exist. Secretory IgA, plasma IgA and IgG isotype levels and specific antibodies may be associated with risk, but probably only if levels fall below those which are protective or a specific antibody response is absent. More work is needed to distinguish between monomeric and dimeric IgA antibodies and to identify IgG antibodies in longitudinal clinical studies. In general, although saliva may prove to be useful as a source of indicators of current disease activity or as a means of assessing responses to treatment, it is unlikely to provide evidence for the existence of risk factors.

Biomarkers↗
PubMed1989

Interstitial deletion, del(4)(q33q35.1), in a mother and two children.

The inheritance of autosomal deletions from affected parents has only rarely been reported. We report an unbalanced interstitial deletion, del(4)(q33q35.1), in a mother and two male offspring. The mother and older sib are mentally retarded but have only mild dysmorphic features. The younger sib, at five months, is showing signs of developmental delay. All three patients show some abnormalities in common with cases that have terminal deletions of 4q with breakpoints at 4q33, but in general exhibit less severe abnormalities. The family illustrates the importance of detailed cytogenetic analysis of children with developmental delay who do not display major dysmorphic features.

Adult↗
PubMed1988

Use of micellar mobile phases and microbore column switching for the assay of drugs in physiological fluids.

The feasibility of directly assaying drugs in physiological fluids using on-line preconcentration and microbore high-performance liquid chromatography has been demonstrated. The untreated sample is injected onto a hydrophobic pre-column, using micellar sodium dodecyl sulfate (SDS) in the case of serum or phosphate buffer in the case of urine, as the load mobile phase. This traps the components of interest which are then backflushed onto a microbore analytical column using a stronger mobile phase. This procedure was then applied to diazepam in serum and phenobarbital in urine. Recovery was linear and quantitative over the range 30-3000 ng/ml for diazepam in serum and 2-200 micrograms/ml for phenobarbital in urine. The diazepam method was specific against caffeine and the three major metabolites of diazepam: oxazepam, temazepam, and nordiazepam. The effects of varying pre-column dimensions, pre-column loading time, and SDS concentration volume were evaluated.

1-Propanol↗