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Biomedical subjects

M Dixon

Publications and source records attributed to M Dixon.

At least 127 records · Page 7Linked to original sources
PubMed1986

Production of a monoclonal antibody to enamelins which does not cross-react with amelogenins.

Developing enamel matrix contains a complex mixture of proteins whose characterization is essential to an understanding of amelogenesis. It is not known whether each component is the product of an individual gene, or whether they are interrelated by physiologic or artifactual breakdown. To define these relationships, monoclonal antibodies were prepared to enamel proteins and we have previously reported the characterization of six antibodies to amelogenins which did not react with enamelins (Christner et al. (1985) Arch. Oral Biol. 30:849-854). We now report the isolation of antibody to enamelins which stains the enamel matrix but does not cross-react with amelogenins. These results suggest that amelogenins and enamelins are distinct classes of proteins.

Amelogenin↗
PubMed1986

Multi-flash campimetry as an indicator of visual field loss in glaucoma.

Multi-flash campimetry is a computer-implemented technique used for the rapid assessment of temporal resolving power across the visual field. On the basis of previous reports that glaucoma patients exhibit impaired temporal sensitivity earlier than conventional perimetric field loss, the question of whether multi-flash campimetry might also be sensitive to the visual consequences of glaucoma was explored. Of the 27 patients that were tested, only one had normal temporal resolving power in both eyes, suggesting that multi-flash campimetry might be a useful aid in determining whether a patient should be diagnosed and treated as a glaucoma suspect or as a confirmed glaucoma patient.

Adult↗
PubMed1986

Prescription of above-knee and below-knee prostheses.

New developments in socket design, materials and fabrication are briefly reviewed. A series of charts is presented which summarize the below-knee and above-knee prescription procedures followed at the Veterans Administration Prosthetics Center.

Age Factors↗
PubMed1985

Liver disease in alpha 1-antitrypsin deficiency. A retrospective analysis of the influence of early breast- vs bottle-feeding.

We identified children with alpha 1-antitrypsin deficiency from the medical records of the Massachusetts General Hospital and Children's Hospital, Boston, and investigated their early feeding history. Between 1969 and 1983, forty children with the deficiency were seen at one or both hospitals. Clinical information was obtained from hospital records and from questionnaires mailed to the parents. Complete morbidity, mortality, and early feeding data were obtained for 32 of the children who were born at 38 to 42 weeks' gestation and whose weights were appropriate for gestational age. We compared the presence of severe liver disease and the death rate of those who had been exclusively breast-fed for one month with those who had been bottle-fed. Severe liver disease was present in eight (40%) of bottle-fed and one (8%) of breast-fed infants. Twenty-four of the 32 infants were still alive at the termination of the study; 12 had been breast-fed and 12 bottle-fed during their first month of life. All eight deceased infants had been bottle-fed. The mortality rate in the bottle-fed group was significantly greater than that of the breast-fed group. Our study suggests that breast-feeding may offer some protection against severe liver disease and early death in infants with alpha 1-antitrypsin deficiency.

Birth Weight↗
PubMed1984

Intestinal uptake of trypsin in newborn and weaned rabbits.

Earlier studies have shown that the uptake of intact proteins from the intestinal lumen into the systemic circulation is increased in neonates. The present experiments tested the uptake of trypsin in newborn compared with 4-wk-old weaned rabbits. Trypsin (200 mg/100 g body wt) was administered by gavage to newborn and 4-wk-old rabbits. Four hours later, the tryptic activity and immunoreactive trypsin (i-trypsin) content of serum from newborn rabbits exceeded that of the older animals. After Sephadex G-200 gel filtration of serum from animals gavaged with trypsin, tryptic activity was detected in the excluded volume (presumably reflecting trypsin bound to alpha 2-macroglobulin), and i-trypsin was detected in the included volume (presumably reflecting trypsin bound to alpha 1-antitrypsin). In vitro experiments demonstrated that large amounts of trypsin were required to overwhelm the antiprotease present in normal rabbit serum. We suggest that complete or partial deficiencies of serum protease inhibitors may permit proteases taken up from the intestinal lumen of the neonate to circulate, reach the liver, and induce tissue injury at this site.

Animals↗
PubMed1984

Dental caries of primary incisors in children with cleft lip and palate.

Visual dental examinations were performed on 64 children ages 18 months through 4 years presenting at a Craniofacial Defects Team charged with diagnostic and referral services. Of the 41 children with cleft lip and/or cleft palate, 13 (32%) had dental caries of one or more maxillary primary incisors. One of the remaining 23 children examined experienced caries of the maxillary primary incisors. In incisors of children having clefts of the alveolus, caries tended to correspond to sites of enamel deficiency in caries-free children with alveolar clefts. Caries patterns in children with clefts involving only the palate resembled "nursing carries". Children with clefts are at significant risk for caries of the primary incisors; a dental prevention program is to be emphasized in referring these children for care.

Child, Preschool↗
PubMed1983

Interferon and antibody titrations using haemagglutinating Togaviridae and trypsinized human erythrocytes.

Several Togaviridae of the alphavirus and flavivirus genera agglutinate trypsinized human group O erythrocytes (THOE) (Shortridge and Hu, 1976). Haemagglutinin titers of Semliki Forest virus (SFV) and Japanese encephalitis virus (JEV) measured with THOE were equivalent to, if not higher than, those obtained with Embden gander erythrocytes, even with unextracted haemagglutinin. Results obtained with THOE in JEV haemagglutination-inhibition tests on sera taken from a previously infected individual over a 20-yr period were similar to those measured during the initial JEV infection. The inhibition of SFV haemagglutinin production as measured with THOE was a very sensitive bioassay for chicken interferon: interferon titers were 6- to 10-fold higher than those obtained with the vesicular stomatitis virus plaque-reduction method. The generally greater availability of human erythrocytes (including those stabilized with glutaraldehyde), the simplicity of the trypsin treatment, and the possibility of using unextracted haemagglutinin recommend this technique for use with haemagglutinating Togaviridae.

ABO Blood-Group System↗
PubMed1983

Changes in the bronchial reactivity of dogs caused by exposure to sulphur dioxide.

The effects of a 2 h exposure to 250 and 400 p.p.m. of SO2 delivered via an endotracheal tube on the reactivity of the dog lung have been studied. Forty-eight hours after exposure to 250 p.p.m. SO2 base-line values of total lung resistance and dynamic lung compliance were unchanged but there was an increase in the bronchoconstrictor response to histamine (20 micrograms/kg I.V.). This enhanced response was vagally dependent. The response of lung irritant receptors to histamine (20 micrograms/kg I.V.) was also increased in these animals. Forty-eight hours after exposure to 400 p.p.m. SO2 resting total lung resistance had increased and resting dynamic lung compliance had fallen. Vagotomy produced a small but insignificant fall in resting total lung resistance. Changes in total lung resistance produced by acetylcholine (40 micrograms/kg I.V.) histamine (20 micrograms/kg I.V.) and 5-hydroxytryptamine (20 micrograms/kg I.V.) were all increased after exposure and these increases were significantly reduced by vagotomy. The falls in dynamic lung compliance produced by these agents were not enhanced by exposure to SO2. The rise in total lung resistance by bilateral vagal stimulation was increased 48 h after exposure to 400 p.p.m. SO2. Exposing dogs to SO2 produced an increase in the reactivity of the lung principally by the enhancement of reflexes. The mechanisms involved are discussed.

Acetylcholine↗
PubMed1983

The changing Alaskan experience. Health care services and cultural identity.

Before Western contact, Alaskan Native populations were self-sufficient in their health practices. Slowly, the Native health care system was replaced by a Western one which was highly effective in treating infectious diseases. As infectious diseases were brought under control by the Indian Health Service, the emergent leading health problems were related to violence, attributed in part to cultural disintegration. New types of Native health providers and new Native-controlled institutions evolved to provide culturally appropriate health and mental health services and to promote a stronger cultural identity.

Alaska↗
PubMed1983

Native healing in Alaska. Report from Serpentine Hot Springs.

Traditional Alaskan Native healing practices, specifically sweat bathing and hot springs bathing, have medical connotations in that they involve sociocultural factors important to practicing medicine among Alaskan Native people. At Serpentine Hot Springs in northwest Alaska, relief for arthritis, back pain, hip pain, headaches, skin rashes and other disorders was sought. The "treatment setting" was an informal bathhouse and bunkhouse and Eskimo tribal doctors and patients were assigned tasks related to healing. Continuity with traditional cultural patterns was achieved in several ways: meals tended to be traditional Eskimo fare, the predominant language spoken was Inupiaq and styles of interaction were Inupiat in character. All patients showed improvement. The experience reported herein is instructive for those seeking innovative approaches treating Native American groups.

Adult↗