Biomedical subjects
B Fox
Publications and source records attributed to B Fox.
Effects of dental health education for mothers with young children in London.
Dental health education for mothers with young children is thought to be capable of achieving a high standard of dental health for these children. This study considers the dental health of a sample of 5-yr-old children whose mothers were given dental health education at an early stage in their child's life. The dental health education was given to one group during home visits and to a second through leaflets sent by post. Comparisons were made with a third group of children whose mothers had been randomly selected to form a control group. Sixty-nine percent of children whose mothers were given advice at home were caries free, compared to 58% of children in the control group. Scores for gingivitis were also significantly lower in the first group. No significant differences in disease levels were seen between children whose mothers had been sent leaflets through the post and those in the control group. In relation to the use of fluoride supplements, 25% of the children whose mothers had been given personal advice received fluoride supplements regularly throughout the period of the study. Children of these highly motivated mothers showed less caries (83% were caries free) and lower levels of gingivitis than children who had never received supplements.
Diagnosis and treatment of dental caries: the clinicians dilemma. Introduction.
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Redox potentials of the flavoprotein lactate oxidase.
The redox potentials for both electron transfers for the enzyme lactate oxidase have been measured at pH 7.0 in 0.01 M imidazole buffer at 25 degrees C. Methylviologen is the electrochemically generated reducing agent capable of transferring both electrons to the enzyme in this spectroelectrochemical experiment. The E0' values are as follows: for EFlox + e- = EFl-., E0'1 = -0.067 +/- 0.006 V; for EFl-. + e- + H+ = EFlredH-, E0'2 = -0.231 +/- 0.004 V. All potentials are reported vs. the standard hydrogen electrode (SHE). Both electron transfers are reversible. Consistent with the 164-mV potential separation, 95% of the enzyme anion radical is thermodynamically stabilized at half-reduction in all experiments.
Dental health education through home visits to mothers with young children.
In the course of a recent experiment a group of 314 mothers with very young children were visited at home by a dental health educator on three occasions. Mothers were given advice about dental health for their children and were offered a free supply of fluoride drops. Results drawn from questionnaires completed at each home visit suggested that dental health education given in this way was able to influence maternal attitudes and behaviour. Virtually all mothers accepted the offer of fluoride drops for their children and after 14-16 months, 65% of the group were still using the supplements.
The distribution and assessment of electron-microscopic abnormalities of human cilia.
The aim of this study was to overcome difficulties of assessing the true incidence of electromicroscopic abnormalities of microtubular structure of cilia by examining large numbers of cilia from each case. The effects of different fixatives on the appearances of cilia were also studied. Bronchial biopsies were examined from 35 subjects who were being investigated for various lung diseases and nasal biopsies from 12 subjects (7 with retinitis pigmentosa (R.P.), and 5 healthy controls). Numerous pieces of normal looking bronchial wall from a lobectomy specimen were used to examine the effect of six different fixatives. 2.9% of bronchial cilia (mean of 890 cilia examined) and 2.4% of nasal cilia (mean of 808 cilia examined) showed microtubular abnormalities. Examining large numbers of cilia established that increased microtubular abnormalities were associated with smoking, chronic pulmonary infection and carcinoma of the lung. There was a significant increase (p less than 0.001) in microtubular abnormalities in nasal cilia in R.P. The appearances of cilia varied considerably with different fixatives. The numbers of dynein arms seen and the ease of recognising radial spokes and microtubules was particularly effected by fixation. The true incidence of microtubular abnormalities can only be ascertained by examining large numbers of cilia.
Abnormal photoreceptors in a dog with a delayed progressive retinal atrophy.
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Mercuric reductase. Purification and characterization of a transposon-encoded flavoprotein containing an oxidation-reduction-active disulfide.
The flavoprotein mercuric reductase catalyzes the two-electron reduction of mercuric ions to elemental mercury using NADPH as an electron donor. It has now been purified from Pseudomonas aeruginosa PAO9501 carrying the plasmid pVS1. In this plasmid system, where the mer operon is on the transposon Tn501, mercuric reductase comprises up to 6% of the soluble cellular protein upon induction with mercurials. The purification is a rapid (two-step), high yield (80%) procedure. Anaerobic titrations of mercuric reductase with dithionite revealed the formation of a charge transfer complex with an absorbance maximum around 540 nm. Striking spectroscopic similarities to lipoamide dehydrogenase and glutathione reductase were observed. These two enzymes, which catalyze the transfer of electrons between pyridine nucleotides and disulfides, are flavoproteins which contain an oxidation-reduction-active cysteine residue at the active site. The expectation that mercuric reductase contains a similar electron acceptor was confirmed when it was shown that mercuric reductase has the capacity to accept four electrons per FAD-containing subunit, and that two thiols become kinetically titrable by 5,5'-dithiobis-(2-nitrobenzoate) upon reduction with NADPH. These are characteristic features of the disulfide reductase class of flavoproteins. Further similarities with at least one of these enzymes, lipoamide dehydrogenase, include the E/EH2 midpoint potential (-269 mV), fluorescence properties, and extinction coefficients of E and EH2. Preliminary observations relevant to an understanding of the mechanism of mercuric reductase are discussed.
Distribution of fatty and fibrous plaques in young human coronary arteries.
We have correlated atheromatous plaque distribution with vessel geometry in coronary arteries from subjects dying of non-cardiovascular causes under 40 years of age. After standardised preparation, the area, and circumferential and longitudinal position of each plaque, were measured in the major coronary arteries. Of 41 sets of vessels, two were free of disease. In the remainder, total plaque area varied from 8 to 586 mm2. Half the cases showed fatty plaques only, and half showed both fatty and fibrous plaques. We analysed the distribution of plaques in those vessels affected only by very early fatty disease. In all vessels, plaques were concentrated proximally, but in the left anterior descending and circumflex branches the wall close to the flow-divider was spared. Circumferential distribution was also not random. In the right coronary artery, lesions were concentrated on the inner wall of the major curvature. In the left anterior descending branch, lesions spiralled anticlockwise from the orifice. We suggest that local mechanical factors may determine these patterns.
Presumptive identification of streptococci with a new test system.
A test is described that could replace bacitracin susceptibility for presumptive identification of group A streptococci as well as 6.5% NaCl agar tolerance for presumptive identification of enterococcal streptococci. The L-pyrrolidonyl-beta-naphthylamide test, based on hydrolysis of pyrrolidonyl-beta-naphthylamide, was used in conjunction with the CAMP and bile-esculin tests to presumptively identify the streptococci. Among the beta-hemolytic streptococci; 98% of 50 group A, 98% of 46 group B, and 100% of 70 strains that were not group A, B, or D were correctly identified by the new presumptive test scheme. Among the non-beta-hemolytic streptococci; 96% of 74 group D enterococcal, 100% of 30 group D nonenterococcal, and 82% of 112 viridans strains were correctly identified by the new presumptive test scheme.
Immunohistological study of human lungs by immunoperoxidase technique.
An unlabelled antibody peroxidase-antiperoxidase method for the detection of IgG, IgM, complement (C3 and Clq), fibrinogen and albumin was applied to routinely processed paraffin sections of lung from 27 cases. The results in 11 cases were compared with those obtained by immunofluorescence using frozen sections. Tissue was obtained from surgical specimens of cases with interstitial pneumonia comprising 10 of the usual type (UIP) and three of the desquamative type (DIP). Tissue was also obtained from the specimens of cases with sarcoidosis (two cases) and granulomatous inflammation of unknown cause (one case). There were 11 control cases, nine with primary carcinoma of the lung and two with metastatic tumours of the lung. Immunoglobulins of various types and complement were seen in diseased lung tissue. Although most of these deposits were probably due to a non-immunological mechanism there was evidence of the possible implication of immune complexes in three cases of UIP and in the interstitial pneumonia present in the two cases of sarcoidosis. The immunoperoxidase technique is a more sensitive method than immunofluorescence and has the additional advantage of the easy identification of the precise sites of the various deposits.
Location of early atheroma in the human coronary arteries.
We have correlated the location of early atheroma with vessel geometry in the major coronary arteries of subjects dying of noncardiovascular causes under 40 yr of age. We analyzed only those vessels affected minimally by very early (fatty) disease. In each of the three major branches, disease was concentrated close to the entrance and diminished with distance downstream. Circumferential distribution of disease was also not random. In the right coronary artery, lesions were concentrated on the inner wall of the major curvature. Immediately downstream of the entrances of both branches of the left coronary artery, the flow-dividing walls were spared. Further downstream in the left anterior, descending branch plaques followed a spiral distribution. We believe these patterns may be determined by local mechanical factors.
Mast cells in the human alveolar wall: an electronmicroscopic study.
Mast cells were identified by electronmicroscopy in the alveolar wall of the lung in 20 subjects (10 normal, 10 abnormal). A quantitative and qualitative study was made of the mast cells. In the normal lung there was an average concentration of 350 mast cells/mm2 of alveolar wall and in the abnormal 523/mm2. Mast cells occupied approximately 1.6-2.1% of the area of the alveolar wall. There was marked variation in the structure of the mast cell granules but no differences between those in the normal and abnormal lungs. There was evidence that constant degranulation of mast cells may be occurring in the lung. The role that alveolar mast cells may play in the vasoconstrictor response to alveolar hypoxia is discussed. It is suggested that the tachypnoea present in asthma may partly be due to release of mediators from sensitised mast cells within the alveolar wall.
Chronic eosinophilic pneumonia and rheumatoid arthritis--coincidental?
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The significance of ultrastructural abnormalities of human cilia.
The electronmicroscopic structure of cilia was studied from the inferior turbinate of the nose in 22 adults, and in 84 biopsies from the bronchial tree of 40 adults. The incidence of compound cilia and abnormal microtubular structures was assessed. There were significant variations in the incidence of abnormalities in different parts of the airways and even within different areas of the same electronmicroscopic section. The focal nature of differences in structure of cilia indicate that abnormalities found in a single biopsy do not necessarily reflect a generalized change in the bronchial tree. Thus, such a finding should not be used as evidence that the abnormalities of cilia are the cause of decrease in mucociliary clearance or that they play a role in the pathogenesis of bronchiectasis and sinusitis.
The objectives of dental health education.
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A hundred years of dental health education.
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Phonemic analysis and severe reading disability in children.
Forty-five first-grade children of average intellectual ability were studied, consisting of one group of average readers, one group with mild reading difficulty, and one group with severe reading disability. A striking deficit in phonemic analysis was observed in children with severe reading disability. These children were unable to segment spoken syllables into individual speech sounds, while children with only mild reading difficulty or none were quite proficient at this skill. In fact, using phonemic analysis scores, it was possible to distinguish the severe reading disability group from the others with perfect accuracy.