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Biomedical subjects

S Richmond

Publications and source records attributed to S Richmond.

At least 127 records · Page 7Linked to original sources
PubMed1987

The screening and categorization of patients: a case for natural selection?

A preliminary study was performed on the feasibility and validity of objective categorization of patients into basic 'treatment types'. The Reflex Metrograph was used for a three-dimensional cast analysis, and an H.P. 9874 A digitizer was used for a two-dimensional radiograph analysis. In both measurement techniques the method error was found to be acceptable. Using the Ricketts 10 Factor Analysis, it was found that by means of 'Clinical deviators' radiographs could be used to distinguish orthognathic cases from the other treatment groups. The three-dimensional study cast analysis showed promise, distinguishing a number of statistically significant factors within the lower arch and between simple and fixed appliance cases. A number of variables which might have been expected to be significant were confounded by their range of values within the groups. Further investigation is required with an improved technique of initial categorization of patients, perhaps by means of a panel of clinicians, and more sophisticated statistical techniques.

Cephalometry↗
PubMed1986

Orthodontic movement of a canine into an adjoining extraction site.

The orthodontic movement of a canine tooth into an adjoining extraction site using a removable appliance is calculated using the finite element method (FEM). The calculated movements are compared, using a reflex plotter, with actual clinical measurements made on several patients. In both cases, wide variations in tooth displacement and hence rotation are found. The most important variable indicated by FEM appears to be the angle at which the load acts on the tooth. The position and magnitude of load have only a minor influence.

Cuspid↗
PubMed1985

Initial tooth movement: force application and pain--a relationship?

Initial dental casts of 24 patients, who had previously completed a discomfort index card for the first 16 days following placement of a fixed appliance, were examined. A method is described whereby the anterior and overall crowding in the relevant dental arch was measured as a tooth/arch discrepancy index using the reflex metrograph. The crowding was measured in three dimensions as the discrepancy between the sum of the anatomic mesiodistal widths of the teeth and the actual mean arch shape canine to canine (3 to 3) and first molar to first molar (6 to 6) inclusive. An additional two-dimensional method using the best "goodness of fit" (least variance) of a parabolic arch shape for the mean arch length in the 6 to 6 crowding measurement is also described. The measurement accuracy of the reflex plotter was less than 0.12 mm. The method error for the crowding measurements expressed as root mean square (RMS) values was 0.97 mm for the anterior tooth/arch, 1.45 mm for the overall tooth/arch discrepancies, and 1.35 mm for the tooth/arch discrepancy based on the best fit of a parabolic curve. It is proposed that since the same bracket width and fully engaged arch wire type were used in every case, some relationship between the initial crowding that reflected the forces applied and the discomfort experienced by the patients might be expected. This was not found to be true. There was no correlation between the total discomfort experienced and the crowding measurements 3 to 3 or 6 to 6.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

A comparison of two- and three-dimensional incisor angles.

Two- and three-dimensional incisor angulations are compared in 40 patients using lateral radiographs and direct dental cast measurement using the Reflex Metrograph coupled to a computer. The two-dimensional upper and lower incisor angulations to the occlusal plane were also compared by the two methods. It was found that: The two-dimensional radiographic and three-dimensional dental cast inter-incisor angulation showed a significant difference at a probability level 0.01 greater than p greater than 0.001. The two-dimensional radiographic and two-dimensional dental cast upper left and right incisor angulations to the functional occlusal plane showed a significant difference at a probability level of 0.01 greater than p greater than 0.001. The significant differences can be attributed to the measurement of the incisor crown angulation in the dental cast measurement and the incisor tip and apex assessment in the radiographic technique. The system of dental cast measurement arguably provides a more realistic and reliable assessment of incisal angles than conventional radiographic measurement techniques.

Cephalometry↗
PubMed1984

Isolation of Chlamydia psittaci from cases of conjunctivitis in a colony of cats.

This report describes the isolation in cell cultures of Chlamydia psittaci from cases of conjunctivitis in a colony of cats. The organism was identified in McCoy cell monolayers by staining the intracytoplasmic chlamydial inclusions with a fluorescent antibody technique, and serological evidence of chlamydial infection in cats was obtained by indirect immunofluorescence. The possible role of C psittaci as an ocular, upper respiratory and reproductive tract pathogen in cats is discussed.

Animals↗
PubMed1984

A large outbreak of keratoconjunctivitis due to adenovirus type 8.

A large nosocomial outbreak of keratoconjunctivitis due to adenovirus type 8 is described. Two hundred cases were identified, 123 by isolation of the virus and 77 by detecting HI antibodies in convalescent sera. Infection usually presented as a severe keratoconjunctivitis, and 107 (54%) of infected patients developed sub-epithelial corneal opacities. The majority (66%) of infections were acquired at the accident and emergency department attached to a large urban eye hospital when patients attended for other reasons; trauma to the eye, especially corneal foreign bodies, was the most frequent cause for the initial attendance. Transmission of virus within the family occurred in 13% of cases, but there was little spread outside family or hospital environments. The outbreak lasted from May to September, 1982, but it was not confirmed by isolation of the virus until the end of June when control measures were instituted. Delay in applying control measures was probably the major factor accounting for this large, prolonged outbreak of epidemic keratoconjunctivitis.

Adenoviridae Infections↗
PubMed1981

Lymphocytotoxic and microbial antibodies in Crohn's disease and matched controls.

Patients with Crohn's disease and age, sex and seasonally matched healthy controls were studied for cold lymphocytotoxic and a variety of microbial antibodies. Lymphocytotoxic antibody titers were increased significantly in the Crohn's patients compared to controls, but did not correlate with any of the microbial titers. Antibodies to a Pseudomonas-like bacterium and Bacteroides vulgatus were also increased in the patients, but titers to Chlamydia trachomatis, rotavirus and Norwalk virus were not elevated above control values. Analysis of microbial antibody within the patient and control groups revealed a significant (P = .001) correlation between antibodies to the Pseudomonas-like bacterium and Bacteroides vulgatus. The elevated titers to the Pseudomonas-like organisms and B. vulgatus are of potential importance, but their significance is not known at this time. There is no evidence of an increased incidence of infection with C. trachomatis, rotavirus or Norwalk virus in Crohn's disease.

Adult↗
PubMed1977

The developmental cycle of Chlamydia trachomatis in McCoy cells treated with cytochalasin B.

The growth of a genital trachoma-inclusion conjunctivitis agent strain of Chlamydia trachomatis in McCoy cells treated with cytochalasin B was studied by quantitative infectivity estimations and by light and electron microscopy. Provided that infection of the monolayer was initiated by centrifuging the infectious particles on to the cells before incubation, this chlamydial strain grew as fast and to as high a titre [approximately 10(7) inclusion-forming units (i.f.u.) per culture] as those chlamydiae which infect cell cultures in vitro without centrifugation. Each i.f.u. inoculated yielded approximately 600 i.f.u., and extracellular infectivity was detected soon after intracellular infectivity appeared. Inclusions were recognized by fluorescent antibody staining techniques early in the developmental cycle when cultures were not infectious and when only reticulate bodies were seen by electron microscopy. Inclusions were recognized in Giemsa-stained preparations examined by dark ground microscopy only when elementary bodies appeared in the inclusions. Iodine staining was not a reliable indicator either of the number of inclusions present or of their infectivity.

Cell Line↗
PubMed1974

Growth of Chlamydia trachomatis in McCoy cells treated with cytochalasin B.

When the fungal metabolite cytochalasin B was added to McCoy cells, multinucleated giant cells developed. Monolayers of these cells proved as efficient as irradiated cells for the growth of three different serotypes of Chlamydia trachomatis and for the primary isolation of chlamydiae from clinical specimens obtained from patients attending a venereal disease clinic. Cytochalasin treatment of McCoy cells provides a convenient alternative to irradiation and should be of value in the isolation of chlamydiae from the eye and genital tract.

Cell Nucleus↗