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Biomedical subjects

A O Jones

Publications and source records attributed to A O Jones.

15 recordsLinked to original sources
PubMed2000

PHEXdb, a locus-specific database for mutations causing X-linked hypophosphatemia.

X-linked hypophosphatemia (XLH) is a dominant disorder of phosphate (Pi) homeostasis characterized by growth retardation, rachitic and osteomalacic bone disease, hypophosphatemia, and renal defects in Pi reabsorption and vitamin D metabolism. The gene responsible for XLH was identified by positional cloning and designated PHEX (formerly PEX) to depict a Phosphate regulating gene with homology to Endopeptidases on the X chromosome. To date, 131 mutations in the PHEX gene have been reported. We undertook to centralize information on mutations in the PHEX gene by establishing a database search tool, PHEXdb (http://data.mch.mcgill.ca/phexdb). This site is dedicated to the collection and distribution of information on PHEX mutations, and is accessible to the scientific community. PHEXdb provides a submission form to allow the addition of newly identified mutations in the PHEX gene. Users can search the database by mutation, phenotype, and authors who have published or submitted mutations. The PHEXdb home page includes links to information pages, which refer to recent publications on PHEX, XLH, and murine Hyp and Gy homologues, and to other web pages relevant to XLH. This resource will facilitate the identification of PHEX structure-function relationships and phenotype-genotype correlations.

DNA Mutational Analysis↗
PubMed1998

Magnetic resonance imaging of the supraspinatus tendon: the significance of signal intensity alterations at the 'critical zone'.

A pictorial essay of normal and abnormal appearances of the supraspinatus tendon is presented. An increased signal intensity within the supraspinatus tendon on short TE sequences is not necessarily abnormal. Increased signal seen within the tendon on modern magnetic resonance imaging (MRI) units is often due to a phenomenon known as the 'magic angle' effect. Only when supraspinatus tendon signal intensity is greater than that of muscle on long TE (T2) sequences should it be considered to be abnormal. The physical basis for the magic angle effect is outlined and a pictorial essay demonstrating the practical implications of this effect is presented. A comparison is made to signal intensity changes seen with partial and complete tears of the supraspinatus tendon. Correlation is made with important morphologic features of partial or complete tears.

Female↗
PubMed1997

Acinic cell carcinoma of the parotid in children.

The imaging findings of two children with acinic cell carcinoma of the parotid gland are presented. Ultrasonic features are emphasized. One of these children, a 6-year-old boy, suffers from the oculocerebrorenal syndrome of Lowe, a rare congenital, inherited condition manifested by defects of the nervous system (mental retardation, hypotonia), eyes (cataracts, glaucoma) and kidneys. To date, no known association exists between these two rare entities. The other child, a 10-year-old girl, was otherwise well. The ultrasound findings of both cases demonstrate features more classic for a benign intraparotid mass than for a potentially malignant lesion. The possibility of acinic cell carcinoma should be considered if a well-defined, relatively homogenously hypo-echoic intraparotid mass is encountered in a child, especially if cystic spaces are present.

Carcinoma, Acinar Cell↗
PubMed1996

Calcium, magnesium, and phosphorus content of hair from two populations of rhesus monkeys.

The use of hair for the assessment of human mineral nutritional status is controversial, yet has potential because of the ease of collection and storage, and the high concentration of minerals in hair. This study generated baseline values for hair macromineral content in the most commonly used primate model for human nutrition and disease, the rhesus monkey. Hair digests from monkeys in Maryland (n = 98) and Puerto Rico (n = 208) were analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). Significant differences existed between the two populations for hair calcium (Ca), magnesium (Mg), and phosphorus (P) (P < 0.01, P < 0.001, P < 0.02). Male hair had higher concentrations of Mg in specimens from the Puerto Rican population (P < 0.001), whereas hair phosphorus was higher in female hair (P < 0.02). There were no significant differences attributable to pregnancy status. Differences in hair content attributable to categorical age were found for Ca and Mg (P < 0.001, P < 0.01). Significant location differences paralleled dietary differences. These values therefore can be considered reference ranges for hair Ca, Mg, and P for free-ranging and caged rhesus monkeys.

Age Factors↗
PubMed1996

Copper, iron, manganese, and zinc content of hair from two populations of rhesus monkeys.

The concentrations of the elements copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) in hair of caged (in Maryland) and free-ranging (in Puerto Rico) rhesus monkey populations were determined. Significant chronological age-related decreases were evident for the trace elements Mn and Zn in both populations (P < or = 0.01) and for Cu and Fe in free-ranging monkeys (P < or = 0.005). The only overall gender difference was higher hair Mn concentration in free-ranging males than in females (P < 0.03). There were no significant differences in hair Cu, Fe, or Mn related to pregnancy status. Hair Zn was lower in samples from pregnant than from nonpregnant monkeys from the caged monkeys (P < or = 0.05), but did not differ in the free-ranging monkeys. Comparison of the two populations revealed that hair Zn levels were significantly higher in caged vs free-ranging animals (P < 0.001). We attribute this higher hair Zn in the caged monkeys to contact and ingestion of Zn from their galvanized enclosures. Hair iron levels were significantly higher (P < 0.001) in free-ranging monkeys, possibly as a result of Fe-rich soil ingestion from their environment. These data support continued investigation of the use of hair as an indicator of the exposure of large groups or populations to potentially high levels of specific minerals, and the use of nonhuman primates as models for the study of trace element deficiency and/or toxicity in humans.

Age Factors↗
PubMed1983

Effects of dietary zinc, manganese, and copper on tissue accumulation of cadmium by Japanese quail.

The beneficial effects of a combined dietary supplement of Zn, Cu, and Mn in decreasing Cd absorption was previously reported. The purpose of this study was to investigate the individual and combined effects of these three elements. In the first two experiments, day-old Japanese quail were fed basal diets containing either requirement amounts of Zn (30 ppm) and Mn (12 ppm) and slightly above requirement levels of Cu (5 ppm). From Day 7 birds were fed either the basal diet or diets containing combinations at twice these concentrations; a 2 X 2 X 2 factorial design was used. 109Cd content and Cd concentration of these diets were 100 mu Ci and 145 micrograms/kg, respectively. In the third experiment, day-old birds were fed either the basal diet or a basal diet containing 109Cd and single additional supplements of either Zn, Cu, or Mn. All birds were killed at 14 days of age. The Cd concentration was determined for the duodenum, jejunum-ileum, liver, and kidney. When the experimental diets were fed for 7 days, only Zn had a protective effect against Cd. Whereas none of the elements reduced the Cd concentration of the duodenum, Zn reduced the Cd in the jejunum-ileum, liver, and kidney by approximately 66, 21, and 11%, respectively. Cu and Mn caused occasional increases of Cd in some tissues. Feeding the experimental diets for 2 weeks resulted in similar responses. Zn nutrition appears to play an important role in protecting against dietary Cd absorption.

Animals↗
PubMed1980

Elemental content of predigested liquid protein products.

Eight commercially available partially digested gelatin liquid products that have been used as a source of protein in dietary regimens for weight reduction and for protein supplementation were analyzed for their elemental composition. These products were prepared either by dry ashing or wet digestion techniques that were suitable for the analysis of individual elements by their respective analytical methods. Analytical methods used to assess the elemental content included inductively coupled argon plasma emission spectrometry for Ca, Mg, P, Fe, Zn, Cu, Mn, Ni, Mo, V, Be, Co, Cr, Tl, Al, Te, Sn and Sb; atomic absorption spectrophotometry for Na and K; hybride generation with atomic absorption spectrophotometry for Se and As; anodic stripping voltammetry for Cd and Pb; and ion selective electrode for F. The content of almost all of the elements in these products was extremely low compared with the amounts supplied daily for normal individuals by usual sources of dietary protein, the adult United States Recommended Daily Allowances, and typical intakes from the Total Diet Study. The following elements were not detectable in significant amounts in these products by inductively coupled argon plasma emission spectrometry: Mo, V, Be, Co, Cr, Tl, Al, Te, Sn, and Sb. The results suggest that use of these predigested liquid protein products as a sole source of nutriment will result in an inadequate intake of all of the essential elements. These products contained insignificant amounts of Ce and Pb, nonessential toxic elements.

Adult↗
PubMed1980

Effects of vitamin C and iron and cadmium metabolism.

Toxic levels of dietary cadmium (5-200 ppm) interfered with iron absorption and produced an iron deficiency. Supplements of iron (particularly the divalent form) and ascorbic acid protected against the cadmium. With very low levels of dietary cadmium (about 0.06-0.08 ppm), typical of those in the diets of humans, supplements of iron(II) and ascorbic acid markedly decreased cadmium concentrations in the liver, kidney, and small intestine. Iron deficiency changed the distribution of cadmium within the body. The effect of ascorbic acid on cadmium metabolism appears to depend primarily, if not entirely, on its influence in improving iron absorption. Maintenance of modest iron stores appears to be very important in minimizing cadmium absorption.

Animals↗
PubMed1979

Effects of nutritional factors on metabolism of dietary cadmium at levels similar to those of man.

Several nutrients are known to affect cadmium toxicity, but little is known about the effect of dietary nutrient levels on absorption and tissue retention of cadmium at low dietary levels, similar to those of man. Feeding gradedlevels of zinc in a casein-gelatin diet to young Japanese quail with 109Cd (as the chloride) and 0.062 ppm added cadmium decreased the cadmium concentrations in the proventriculus-ventriculus, duodenum, jejunum-ileum, and the liver, but not in the kidney. Zinc also affected some zinc, iron, manganese, and copper tissue levels. Different tissue concentration patterns of cadmium and essential minerals were obtained with two purified control diets, one based on casein-gelatin and the other on soy isolate as the principal protein sources. The data show that relatively small dietary changes can markedly affect tissue levels of cadmium and that a low intake of zinc may increase the risk to dietary cadmium exposure. The complexity of the nutrient interrelationships and their effects on cadmium require further study to define mechanisms, which may be similar to those produced by low cadmium intakes in man.

Animal Nutritional Physiological Phenomena↗