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Biomedical subjects

S M Cochrane

Publications and source records attributed to S M Cochrane.

10 recordsLinked to original sources

A comparison of the perception of facial profile by the general public and 3 groups of clinicians.

Orthodontists and maxillofacial surgeons frequently plan orthognathic treatment to produce an "ideal" Class I occlusion and skeletal relationship. The aim of this study was to investigate whether the preferred facial profile chosen by orthodontists, maxillofacial surgeons, dental students, and members of the general public conformed to a Class I profile. Photographs were taken of 2 male and 2 female adult subjects with Class I profiles, and by means of a computer program the images were manipulated to produce Class II, Class III, and long face profiles. The orthodontists, surgeons, dental students, and members of the general public ranked each group of 4 photos in order of their attractiveness. Orthodontists and maxillofacial surgeons were found to be significantly more likely to choose a Class I skeletal relationship as the most attractive profile. A significant difference was found between orthodontists and dental students (P < 0.01) and between orthodontists and the general public (P < 0.001) with regard to the assessment of the Class I profile as the most attractive, when all 4 subjects were considered. Similar results were noted for maxillofacial surgeons. Whether the assessor was an orthodontist, maxillofacial surgeon, or a member of the general public was found to be significant when examining subjects 1 (female) and 3 (male). The sex of the assessor was also a significant factor for subject 3 (male), where female assessors were more likely to rank the Class I profile as most attractive (P < 0.05).

Adult↗

The permselectivity of glomerular basement membrane can be compromised by glycation or by exposure to low levels of hypochlorite.

Earlier studies indicated that chemically crosslinking glomerular basement membrane (GBM) rendered it more permeable to water and to macromolecules. Here possible mechanisms for the introduction of crosslinks into GBM under pathological conditions were explored. Glycation with glucose and with fructose over periods of 2 wk (fructose) and 6 weeks (glucose) rendered the GBM more permeable to water and myoglobin as judged from in vitro ultrafiltration behaviour. The membranes were also made more permeable to serum following glycation. The permeation changes were shown to be dependent on glycoxidative reactions judging by their inhibition by EDTA and DTPA. Aminoguanidine also prevented glycation from altering the permeability of GBM. Fluorescence studies indicated the formation of bityrosine in glycated GBM. Studies with oxidants showed that while hydrogen peroxide superoxide and peroxynitrite had little effect on GBM, hypochlorite anion was capable of increasing GBM permeability to water, myoglobin, albumin and serum. Changes in permeation were induced by very low quantities of hypochlorite, well within the range of the amounts of hypochlorite formed by activated neutrophils. Thus glycoxidation, or oxidation by hypochlorite, are chemical mechanisms by which GBM permeability can be increased.

Basement Membrane↗

Late developing supernumerary teeth in the mandible.

This paper presents two cases in which supplemental premolars were an incidental finding. Although anomalies of tooth number and form are quite common, both cases demonstrate late forming supernumeraries with one case illustrating their development in a more unusual site. It is not routine practice to screen for late development of teeth during orthodontic treatment. Therefore the possibility of their interference with occlusal development or orthodontic mechanics such as space closure, should always be kept in mind.

Bicuspid↗

In vitro glycation of glomerular basement membrane alters its permeability: a possible mechanism in diabetic complications.

The permeability of glomerular basement membrane (GBM) was assessed in vitro by the filtration of solutions of proteins across films formed from isolated pig GBM. Incubation of the films with fructose or glucose increased their permeability to water and serum albumin. The effect of fructose was similar to that previously noted for films crosslinked with glutaraldehyde. The metal chelator DTPA abolished the effects of glycation; EDTA was partially effective in this respect. Transition metal catalysed formation of glycoxidation induced crosslinks may explain the increased permeability of glycated GBM.

Animals↗

Pharmacokinetics of phenobarbital in the cat following multiple oral administration.

Phenobarbital was administered orally to seven healthy cats at a dose of 5 mg/kg once a day for 21 days. Serum phenobarbital concentrations were determined using a commercial immunoassay technique. A one-compartment model was used to describe the final elimination curve. The elimination half-life (t1/2 b) after the final day of treatment was 43.3 +/- 2.92 h. The large apparent volume of distribution of 695.0 +/- 43.9 mL/kg suggests that the drug was widely distributed within the body. The t1/2 b following multiple oral administration was significantly shorter than previously reported for a single oral dose of phenobarbital in the cat. Analysis of pharmacokinetic results after days 1 and 21 of treatment suggested that the elimination kinetics of phenobarbital did not change significantly with multiple oral administration. It appears that differences in elimination kinetics can exist between populations of cats. These differences emphasize the need for individual monitoring of cats receiving phenobarbital.

Administration, Oral↗

Pharmacokinetics of phenobarbital in the cat following intravenous and oral administration.

Phenobarbital was administered to eight healthy cats as a single intravenous dose of 10 mg/kg. Serum phenobarbital concentrations were determined using an immunoassay technique. The intravenous data were fitted to one-, two- and three-compartment models. After statistical comparison of the three models, a two-compartment model was selected. Following intravenous administration, the drug was rapidly distributed (distribution half-life = 0.046 +/- 0.007 h) with a large apparent volume of distribution (931 +/- 44.8 mL/kg). Subsequent elimination of phenobarbital from the body was slow (elimination half-life = 58.8 +/- 4.21 h). Three weeks later, a single oral dose of phenobarbital (10 mg/kg) was administered to the same group of cats. A one-compartment model with an input component was used to describe the results. After oral administration, the initial rapid absorption phase (absorption half-life = 0.382 +/- 0.099 h) was followed by a plateau in the serum concentration (13.5 +/- 0.148 micrograms/mL) for approximately 10 h. The half-life of the terminal elimination phase (76.1 +/- 6.96 h) was not significantly different from the half-life determined for the intravenous route. Bioavailability of the oral drug was high (F = 1.20 +/- 0.120). Based on the pharmacokinetic parameters determined in this study, phenobarbital appears to be a suitable drug for use as an anticonvulsant in the cat.

Administration, Oral↗

Treatment of cyclophosphamide-induced hemorrhagic cystitis in five dogs.

Sterile hemorrhagic cystitis developed in 5 dogs after treatment with cyclophosphamide. Four dogs were being treated with various antineoplastic protocols, and the fifth dog had recurrent immune-mediated thrombocytopenia. In all instances, clinical signs of hematuria and stranguria persisted after cyclophosphamide administration was discontinued. Three dogs required cystotomy to remove necrotic mucosa and calculi. The other 2 dogs were treated with intravesicularly administered dimethyl sulfoxide to decrease inflammation and to inhibit fibroplasia of the bladder wall. In 4 dogs, clinical signs resolved after treatment. The fifth dog, treated surgically, continued to have intermittent urinary incontinence attributable to residual bladder wall fibrosis.

Animals↗