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Biomedical subjects

T C Aitchison

Publications and source records attributed to T C Aitchison.

At least 55 records · Page 3Linked to original sources
PubMed1993

The in vitro lysozyme susceptibility of Candida albicans cultured in carbohydrate-supplemented media.

The in vitro lysozyme susceptibility of three oral isolates of Candida albicans cultured in carbohydrate-supplemented media was studied. Lysozyme was shown to have a dose- and time-dependent killing effect on C. albicans isolates. Fungicidal activity persisted to varying degrees when yeast isolates were cultured in a variety of carbohydrates (glucose, galactose, sucrose, maltose, xylitol and lactose) before exposure to 20 micrograms/ml lysozyme. Sucrose and galactose grown yeasts exhibited increased resistance to lysozyme compared with (in decreasing order) those grown in glucose, maltose, xylitol or lactose. Further, the C. albicans isolates tested demonstrated strain variations in their susceptibility to lysozyme. These results suggest that dietary carbohydrate may play a role in modulating the yeast cell populations in the oral cavity by altering the fungal susceptibility to salivary lysozyme.

Analysis of Variance↗
PubMed1993

Improved repeatability of 12-lead ECG analysis using continuous scoring techniques.

This study describes a method for improving the day-to-day and minute-to-minute repeatability of the deterministic computer-assisted diagnosis of left ventricular hypertrophy. Conventional upper limits of normal for many age-dependent electrocardiographic parameters have been replaced by continuous equations, thereby, eliminating points of discontinuity that can contribute to lack of repeatability. Estimates of the normal amounts of variability present in many electrocardiographic parameters that are used in the diagnosis of left ventricular hypertrophy are calculated. These estimates are then used together with a smoothed version of a score function to form the basis of the new technique. The implementation of smoothing techniques enhances the repeatability of the Glasgow electrocardiographic analysis program. With respect to the electrocardiographic diagnosis of left ventricular hypertrophy, these methods eliminate 44% of the day-to-day and 50% of the minute-to-minute inconsistencies in computer reports.

Adult↗
PubMed1993

The in vitro lysozyme susceptibility of Candida species cultured in sucrose supplemented media.

The in vitro sensitivity to lysozyme of twelve isolates of Candida (three isolates each of C. albicans, C. tropicalis, C. glabrata and C. krusei) pre-incubated in sucrose supplemented media, was determined by a growth inhibition assay. In general, C. albicans and C. tropicalis exhibited increased susceptibility to lysozyme as the sucrose concentration in the growth medium was reduced. Candida krusei demonstrated the reverse effect and C. glabrata isolates showed different trends. Although generally the Candida species examined were susceptible to lysozyme in the decreasing order of C. glabrata, C. albicans, C. tropicalis and C. krusei, differences in susceptibility were noted among different isolates within a given species. These results imply that salivary lysozyme and dietary carbohydrates may exert selective pressure on oral colonization by Candida species.

Candida↗
PubMed1992

Cutaneous malignant melanoma, Scotland, 1979-89. The Scottish Melanoma Group.

The Scottish Melanoma Group (SMG) was established in 1979 to assess mortality from and incidence, features, pathological data, and management of cutaneous malignant melanoma in Scotland. Incidence during the first five years and five-year survival have already been reported. We now have data about incidence and mortality over eleven years in relation to anatomical site and pathological types. From 1979 to 1989, 1354 male and 2459 female patients with primary cutaneous malignant melanomas were first diagnosed in Scottish residents. The incidence rate per 100,000 population per year has increased from 3.4 in 1979 to 7.1 in 1989 for men, and from 6.6 to 10.4 for women. The overall increase over eleven years is 82% (7.4% per year). The greatest rates of increase are seen in lesions of the superficial spreading histogenetic type, arising on the female leg and the male trunk. Following public education programmes started in 1985, the proportion of all melanomas less than 1.5 mm thick has shown a sustained and significant increase. Mortality data for 1661 patients for whom a minimum of five-year follow-up is available shows five-year survival of 71.6% overall (77.6% for women, 58.7% for men). The survival advantage for women persists when appropriate statistical adjustment is made for thickness, ulceration, and histogenetic type. These data are useful in designing public education programmes aimed at both primary and secondary prevention of melanoma and in auditing changes in trends that might result from such education.

Adolescent↗
PubMed1992

Staphylococcus aureus and intra-nasal mupirocin in patients receiving isotretinoin for acne.

Thirty patients commencing isotretinoin for acne were entered into a double-blind, randomized, placebo-controlled trial to investigate the effect of pulsed intra-nasal mupirocin ointment on Staphylococcus aureus colonization and isotretinoin-related side-effects. In both mupirocin and placebo groups there was an increase in isolation of S. aureus throughout the period of treatment with isotretinoin from the anterior nares, facial skin and lips. However, these increases were significantly less in the mupirocin-treated group. A high proportion of all patients suffered inflammatory side-effects of isotretinoin such as cheilitis and nasal vestibulitis, with their maximum severities being recorded 2 months after starting isotretinoin. In spite of the smaller increase in S. aureus colonization in the mupirocin-treated group no difference was demonstrated in either the incidence of specific S. aureus infections (e.g. furunculosis) or the prevalence of isotretinoin-related inflammatory side-effects. Furthermore, no relationship between the presence of S. aureus and the severity of inflammatory side-effects was shown. Streptococcus species were isolated on four separate occasions from four different patients during the study but their pathogenicity was unclear. These findings suggest that although pulsed intra-nasal mupirocin produces a significant reduction in isotretinoin-related staphylococcal colonization, its routine use cannot be justified on the basis of clinical benefit.

Acne Vulgaris↗
PubMed1991

Prediction of caries increment in Scottish adolescents.

Salivary, clinical, and microbiological factors were compared with subsequent 2-yr caries increment in a group of 372 Scottish adolescents. The caries increment was significantly correlated with previous caries experience, salivary buffering capacity and counts of lactobacilli, mutans streptococci and candida. Veillonella levels and salivary flow rate were not correlated with caries increment. Significant improvements in the predictions were obtained when the results of more than one test were included using stepwise regression analysis. On an individual basis, using stepwise discriminant analysis, the caries increment group (low, medium, or high) was identified correctly in 49% of all subjects, but this was reduced to 45% if previous caries experience was excluded from the analysis.

Adolescent↗
PubMed1990

Assessment of a contact-plate sampling technique and subsequent quantitative bacterial studies in atopic dermatitis.

The aerobic bacterial flora of 20 patients with atopic dermatitis and 19 control subjects was extensively sampled using the Williamson and Kligman scrub technique and a contact-plate method (cysteine lactose electrolyte deficient media). Comparison of the two quantitative techniques showed that the contact plate is a reliable and convenient alternative to the scrub technique for the quantification of Staphylococcus aureus, micrococci and coagulase negative staphylococci. Quantification of bacterial flora using both techniques showed high rates of colonization by S. aureus on both involved and clinically normal skin of patients with atopic dermatitis. A linear increase in S. aureus counts with increasing severity of dermatitis was found. In contrast, diphtheroids showed a trend of decreasing isolation rates and counts as the severity of the dermatitis increased. Isolation rates and absolute counts for micrococci/coagulase negative cocci were unaffected by the severity of the dermatitis.

Adult↗
PubMed1990

Caries prevalence and microbiological and salivary caries activity tests in Scottish adolescents.

Salivary and microbiological caries activity tests were investigated on three occasions in a group of 372 Scottish adolescents. Counts of lactobacilli, mutans streptococci, and candida were consistently and significantly associated with caries prevalence, as either DS or DMFS score, and buffering capacity was consistently inversely related to DMFS score. However, veillonella counts and salivary flow rate were not correlated with caries prevalence. Significant improvements in the associations were obtained when the results of more than one test were included using stepwise regression analysis. On an individual basis, at most, stepwise discriminant analysis identified the DMFS group correctly in 49% of all subjects, and the DS group in 47%.

Adolescent↗
PubMed1990

Salivary levels of mutans streptococci, Lactobacillus, Candida, and Veillonella species in a group of Scottish adolescents.

Salivary levels of mutans streptococci, Lactobacillus, Candida, and Veillonella species were investigated on three occasions at annual intervals in a group of 372 Scottish adolescents. Counts of the micro-organisms studied were logarithmically distributed, with Candida spp. being isolated from approximately half the subjects. Counts of lactobacilli, mutans streptococci, and candida were significantly intercorrelated, while veillonella were associated consistently with mutans streptococci alone. Levels of each of the four micro-organisms were significantly correlated over the three examinations, with levels of the Candida spp. being the most stable over the period studied.

Adolescent↗
PubMed1990

The effect of sucrose application and implantation of mutans streptococci on the microbial composition of three-week experimental plaque--an in situ study.

This study describes the predominant cultivable microflora of three-week-old plaque samples obtained from human enamel sites, on the basis of microbial identification of over 9000 fresh isolates. Lower removable appliances, on which were mounted enamel sections and slabs, were worn by five young adult subjects under three experimental protocols. These were (1) 'normal' plaque conditions, (2) extra-oral sucrose applications nine times daily, and (3) inoculation of each subject's own mutans streptococci onto the enamel test sites and sucrose applications, as described above. With the exception of slightly higher proportions of Gram-negative bacilli associated with slab plaque following sucrose application, no significant differences in percentage or absolute counts of organisms were found between normal and sucrose plaques. The inoculation of mutans streptococci, combined with extra-oral sucrose applications, was associated with significantly higher percentages and absolute mean counts of both mutans streptococci and lactobacilli, and lower proportions of S. sanguis and S. oralis. Although the isolation frequency of mutans streptococci increased in all subjects and the overall mean proportion rose following inoculation, considerable inter-subject variation was seen in mean percentage counts of these organisms isolated from the three-week plaque samples.

Adult↗
PubMed1989

Personal risk-factor chart for cutaneous melanoma.

Information from a case-control study of all patients with cutaneous malignant melanoma first diagnosed in Scotland in 1987 has been used to derive a personal risk-factor chart that can be used by both the medical profession and the general public. The relative risk of cutaneous melanoma is estimated from the four strongest risk factors identified by conditional logistic regression. These factors are total number of benign pigmented naevi above 2 mm diameter; freckling tendency; number of clinically atypical naevi (over 5 mm diameter and having an irregular edge, irregular pigmentation, or inflammation); and a history of severe sunburn at any time in life. Use of this risk-factor chart should enable preventive advice for and surveillance of those at greatest risk.

Adolescent↗
PubMed1988

Sickness scoring and response to treatment as predictors of outcome from critical illness.

A physiological sickness scoring system (SS), based on the APACHE II score, has been used to assess outcome from critical illness in 128 patients admitted to a general intensive care unit. Physiological data were collected on each patient from admission until death or discharge from the unit, and survival was recorded as survival to home. The admission SS correctly classified 80.6% of survivors, and 70.4% of non-survivors. Predictive power did not improve with time using the daily SS. However, when the proportional change in SS over time was included in the analysis, predictive power improved; and at day 4, 87.1% of survivors and 75% of non-survivors were correctly classified. At intermediate levels of sickness severity (admission score of 13-18), a reduction in SS of 30% by day 4 reduced the risk of death by 32%; at higher levels (greater than 18) a similar reduction in SS was associated with a 47% reduction in death-risk. Failure to obtain a reduction in score by day 4 was associated with increased risk of death. Survivors consistently showed a greater fall in SS by day 4 than non-survivors. The APACHE score and its modifications provide an accurate, unitary measure of physiological disturbance. Correction of abnormal physiology, and the measurement of responsiveness to therapy are important components in the prediction of outcome from critical illness.

Adult↗
PubMed1988

Bovine acute phase response following turpentine injection.

The serum levels of five proteins, alpha 1 antitrypsin, ceruloplasmin, fibrinogen, haptoglobin and seromucoid, were measured daily in calves after the subcutaneous injection of oil of turpentine. Raised concentrations were detected on the second and third days after injection with peak levels occurring on the fourth to seventh days and returning to normal by the 17th day. Levels of four of these proteins, alpha 1 antitrypsin, ceruloplasmin, haptoglobin and seromucoid were compared in the same calves following three different doses of turpentine. Levels of haptoglobin and seromucoid varied with the dose whereas ceruloplasmin and alpha 1 antitrypsin levels did not.

Acute-Phase Proteins↗
PubMed1986

Sedation in intensive care: morphine and renal function.

Intravenous morphine infusions have been administered to 12 critically-ill patients during controlled ventilation. Acute oliguric renal failure was present in 4 patients, who were treated with a combination of haemofiltration and haemodialysis. Severity of physiological disturbance was assessed using a modified APACHE Score, level of sedation by a linear-analogue scale, and blood morphine levels by high-pressure liquid chromatography. Morphine clearance was impaired in renal failure, and was dependent on haemofiltration volumes; accumulation of morphine did not occur during this form of treatment. Conscious level was clearly more closely related to the degree of physiological disturbance than blood morphine levels; and for a given blood morphine level, depression of consciousness was more pronounced the greater the degree of physiological disturbance. Use of a physiological sickness score may help to clarify some of the factors influencing cerebral function during critical illness. Careful clinical monitoring of level of sedation is important in patients with oliguric renal failure receiving morphine, and haemofiltration appears to reduce the risk of morphine accumulation in these patients.

Acute Kidney Injury↗