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Biomedical subjects

C K Anderson

Publications and source records attributed to C K Anderson.

At least 19 recordsLinked to original sources
PubMed1991

Longitudinal evaluation of condylar position in extraction and nonextraction treatment.

In 111 patients pretreatment and posttreatment condylar position was evaluated with corrected tomograms taken with the mandible in centric occlusion. Seventy-nine of the patients were treated by nonextraction procedures and 32 were treated by extraction procedures, 27 of the patients with the extraction of one or more premolars and 5 with the extraction of one or more anterior teeth. When the condylar positions before and after treatment were compared in the entire sample of 111 patients, in the nonextraction patients, in the extraction patients, and in extraction patients relative to nonextraction patients, no statistically significant differences were found. Thus condylar position was stable during treatment and did not behave differently under extraction and nonextraction conditions. On an individual basis, condylar retropositioning, as defined in this study, occurred in only nine of the 222 joints examined and was noted in patients treated both with and without extraction.

Adult↗
PubMed1991

Interpretation of biopsies of "normal" urothelium in patients with superficial bladder cancer. MRC Superficial Bladder Cancer Sub Group.

In the course of a Medical Research Council trial of intravesical chemotherapy, biopsies were taken from apparently normal bladder urothelium near to newly diagnosed superficial bladder cancers in 417 patients. Differences were noted in the rates at which histological features were described in different centres. To gain more information about the reproducibility of the pathological findings, a group of 6 pathologists (5 from the UK and 1 from the USA), all having a special interest in urological pathology, were asked to examine a representative sample of 92 slides. They were then asked to re-examine 30 of them after an interval of at least 6 months. At first examination and at re-examination the slides were assessed using a standard proforma. However, the definitions of the categories were left unspecified for the pathologists to use their own criteria. The 5 UK pathologists then met to establish a consensus view of each slide. The results indicated that: (1) The reporting of non-dysplastic changes varied so much between pathologists as to render it of little value to clinical practice. (2) There were wide variations between different pathologists in the reported incidence of dysplastic change. (3) On a second review the pathologists reproduced their own assessment on only 62% of occasions. (4) Even after discussion between pathologists there was no consensus on the diagnosis of mild as opposed to moderate dysplasia. Consensus was reached on all biopsies which showed either severe dysplasia or carcinoma in situ. (5) In adopting a policy of taking urothelial biopsies, urologists should be aware of the imprecision and lack of reproducibility in the interpretation of such biopsies. (6) Biopsies of cystoscopically normal urothelium may not be a useful guide in defining therapy.

Biopsy↗
PubMed1990

Response of fibroblast cultures from ataxia-telangiectasia patients to oxidative stress.

The object of this study was to determine whether ataxia-telangiectasia (AT) cells are more sensitive than normal cells to reduced oxygen species generated either during normal cell processes or resulting from metabolism of xenoblotics. To test this hypothesis four AT and four normal fibroblast cultures were exposed to hydrogen peroxide (H2O2) and the induction of micronucleated cells was assayed. AT cultures responded to the H2O2 treatment with a greater increase in micronucleus frequencies than that observed in normal cultures (P less than 0.01). At time course study showed that an elevation in micronucleus frequencies occurred earlier in AT cultures (significant increase by 1.5 h after treatment) than in normal cultures, possibly indicating a G2-phase sensitivity of AT cells to H2O2. The addition of an aqueous extract of areca nut to the cultures, as an example of exogenous stress, induced a greater frequency of micronucleated cells in AT cultures than in the normal cultures. These results suggest that the AT syndrome may serve as a model for investigating the role of reduced oxygen species in cancer.

Areca↗
PubMed1987

Extra-urethral ectopic prostate.

Extra-urethral ectopic prostatic tissue is a distinct entity which has been identified in the bladder of seven patients and may be more common than previously thought. Such tissue probably derives from the subtrigonal glands of Lowsley.

Adult↗
PubMed1986

Prediction of overexertion injuries using biomechanical and psychophysical models.

This paper summarizes a three year epidemiological study conducted in five large industrial plants in order to evaluate the validity of two alternative modeling approaches to overexertion injury prediction. Detailed biomechanical and psychophysical job evaluations were performed for 55 industrial jobs comprised of 2934 potentially stressful manual materials handling tasks. The medical experiences of 6912 incumbent workers were monitored retrospectively for two years and prospectively for one year to establish a data base for comparison of the different models. The results show that each of the models can be used to predict both the incidence and severity of certain overexertion types of injuries such as contact, musculoskeletal and back injuries. The application of these models to identify or design administrative and engineering controls, however, may be limited as a result of the inherent correlation between the available indices and multifaceted jobs.

Accidents, Occupational↗
PubMed1986

A study of lumbosacral orientation under varied static loads.

This paper describes a study of lumbar and sacrum orientations in select standing postures with the patient holding different loads in the hands. Vertebral rotation data were gathered from two young, healthy men and two young, healthy women while they performed static lifts at two load levels and in postures ranging from erect standing to deep squatting. The results disclosed a predictable reorientation of the sacrum and lumbar spine for both men and women as a function of torso and knee angles. Nonlinear second-order regression models of torso angle and knee angle versus reorientation angle were fit to the data with resulting r2 values of about 0.89. Load was not found systematically to affect the sacrum/lumbar reorientation.

Adult↗
PubMed1985

A biomechanical model of the lumbosacral joint during lifting activities.

A biomechanical model of the lumbosacral region was constructed for the purpose of systematically studying the combined stresses and strains on the local ligaments, muscles and disc tissue during sagittal plane two-handed lifting. The model was validated in two ways. The first validation was a comparison of experimental study results with model predictions. In general predictions compared very reasonably with observed values of several authors with the exception of strain predictions on the articular ligaments. Second, a sensitivity analysis was performed over a wide range of lifting tasks. The predicted stress/strain values followed anticipated patterns and were of reasonable magnitudes. On the basis of the results of the sensitivity analysis it was concluded that typical lifting tasks can lead to excessive disc compressive forces, muscle moment generation requirements, and possibly lumbodorsal fascia strains. Conversely, annulus rupture of a healthy disc due to overstrain appears very unlikely.

Biomechanical Phenomena↗
PubMed1985

Excess days lost as an index for identifying jobs with ergonomic stress.

A new health impact index, excess cost, is advocated for identifying jobs in need of further study regarding ergonomic problems. The excess cost index is compared with incidence rate, excess count, and severity rate indices in terms of concept and appropriateness to the purpose. The four indices are illustrated with data regarding medical leave from an automobile assembly plant and evaluated in terms of ability to identify jobs most strongly contributing to excessive days lost.

Absenteeism↗
PubMed1979

Embryotoxic effects of pine needles and pine needle extracts.

A heat stable toxin present in needles of ponderosa pine was found to be soluble in methanol, ethanol, chloroform hexanes and 1-butanol. The embryotoxic effects of fresh green pine needles and a chloroform/methanol extract were determined by measuring embryo resorption in pregnant mice. Autoclaving the needles and extract for 1 hour prior to feeding enhanced the embryoresorptive effect by 28% and 32%, respectively. The results of this study revealed that the embryo resorptive dose (ERD50) of heat stable toxin for 1 mouse was 8.95 gms. for fresh green pine needles and 6.46 gms. for autoclaved green pine needles. In addition to embryocidal effects, feeding of the toxin resulted in significant weight loss in adult mice.

Animals↗
PubMed1978

Immunological studies of testicular tissue in oligozoospermic and azoospermic patients.

Testicular biopsies from 6 oligozoospermic and 12 azoospermic patients were examined histologically and immunohistologically. Evidence of maturation arrest and of Type II allergic reactions involving tubular basement membranes was found in all oligozoospermic patients. No evidence of an immune reaction was found in 9 azoospermic patients with maturation arrest. Unilateral or bilateral germ cell aplasia with evidence of mixed Type II and III or Type III and IV reactions was present in 2 oligozoospermic and 2 azoospermic patients. The findings have been interpreted to indicate that maturation arrest and germ cell aplasia may occasionally be linked in a chain of immunological events, initiated possibly by damage to tubular basement membranes. No correlation was demonstrable between the histological and immunohistological findings and indirect immunofluorescent tests for sperm antibodies. It is suggested that testicular biopsy is a potentially hazardous procedure in the investigation of infertility, and that prepubertal testicular tissues as well as sperm be used as antigens in the immunological investigation of infertility.

Antibodies↗
PubMed1978

Urethral tumours.

A series of 33 patients with urethral tumours has been studied to assess the risk of dissemination by endoscopic diathermy. This risk is less than that of cystourethrectomy. Urethral tumours should be treated like the vesical tumours they follow and so closely resemble: by endoscopic treatment while they remain small, sparse and superficial; by cystourethrectomy as soon as they become larger and more extensive. Recurrence of tumour in the urethral stump following cystectomy should always be treated by urethrectomy.

Aged↗
PubMed1978

Right ventricular heart failure of Montana cattle.

Congestive right ventricular heart failure of Montana cattle is characterized clinically by an accumulation of edematous fluid in the brisket region and ventral portions of the body but not of the legs. A well developed jugular pulse is first observed followed by a watery diarrhea and usually by the accumulation of excessive fluid in the pleural and peritoneal cavities. As the case develops over a period of two to three weeks, the ventral edema becomes more marked (Fig. 1) and straw-colored fluid may accumulate in the body cavities until the abdomen is distended and breathing labored. Death may occur as a result of respiratory failure due to the large volume of pleural fluid or from general debilitation as a result of the right ventricular failure. The incidence of this type of heart failure in Montana cattle is highest on moist mountain valleys. Eighty-one of 113 cases observed over a seven year period occurred in cattle that were maintained at altitudes of 1525 m or below. This paper describes the conditions under which the disease occurs in Montana and compares the hemograms of clinically ill and healthy cattle.

Animals↗
PubMed1977

Vascular and glomerular changes in the ageing kidney.

Glomerular size, shape and number were examined in 44 human kidneys obtained at necropsy. Intrarenal vascular appearances were assessed histologically and by post-mortem angiography. The mean cross-sectional area of glomeruli varied nearly three-fold and glomerular number varied more than three-fold when kidneys from different adult subjects were compared but kidneys from the same subject resembled one another in glomerular size and number. A significant negative correlation existed in the adult between glomerular number and dimensions. Glomerular numbers in the few immature kidneys studied were similar to those in adult kidneys but glomeruli were smaller. Glomerular numbers tended to decline as age and severity of age-related vascular changes increased but correlation was poor. The possibility remains that glomerular involution in the senescent kidney occurs independently of events in the vessels. In men, but not in women, totally hyalinised glomeruli were observed more frequently with increasing age but their presence did not appear to be related to the degree of vascular change. In the senescent kidney, glomerular lobulations tended to disappear. This, together with glomerular loss, must result in a reduction in the area available for filtration. Assessments of total glomerular surface area should take account of glomerular shape and dimensions as well as numbers.

Adult↗
PubMed1977

Pine needle toxicity in pregnant mice.

Eight groups of pregnant mice were fed various preparations of ground pine needles or aqueous extracts thereof. An additional group was fed only Purina mouse cubes. Ground pine needles were more toxic to both adult mice and embryos than were the various water extracts. Reproductive failure occurred early in the gestational period. A water soluble and heat labile toxin suggestive of a mycotoxin was demonstrated in water extracts. Pine needle fiber contained a heat stable toxin which was insoluble in water. Evidence suggested the possible presence of a third toxin lethal for adult mice. Results suggested that the heat stable toxin is the one of greatest importance as a source of reproductive failure in mice. Toxins produced by fungi were considered to be of secondary importance.

Animals↗