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Biomedical subjects

J M Gardner

Publications and source records attributed to J M Gardner.

At least 19 recordsLinked to original sources
PubMed1995

In vivo gene delivery and expression of physiological levels of functional human factor VIII in mice.

Hemophilia A is caused by blood coagulation factor VIII (FVIII) deficiency and is an attractive target for gene therapy. However, features of FVIII physiology, such as the instability of the mRNA and protein, have provided obstacles to the design of a feasible strategy for the transfer and expression of the human FVIII gene in vivo. We have constructed a recombinant adenoviral vector, Av1ALH81, that contains the human FVIII cDNA from which the B-domain has been deleted (BDD FVIII) and extensively characterized this vector in vitro and in vivo. In vitro, HepG2, human hepatoma cells, transduced with Av1ALH81 secreted high levels of biologically active human BDD FVIII measured by the Coatest bioassay (> 2,400 mU per 10(6) cells per 24 hr). Administration of Av1ALH81 to mice, via tail vein, resulted in expression of human BDD FVIII in the mouse plasma at levels averaging 307 +/- 93 ng/ml 1 week post-injection, measured by a sensitive human FVIII-specific ELISA. Normal FVIII levels in humans are 100-200 ng/ml, and therapeutic levels are as low as 10 ng/ml. Purification of the human FVIII from the mouse plasma, and subsequent Coatest analysis, revealed that the human FVIII produced in the mice was biologically active. In addition, the duration of FVIII expression in vivo was followed, and high-level FVIII expression was sustained over a period of several weeks. The finding that an adenoviral vector can mediate high-level expression of human FVIII in an animal model provides the basis for the development of gene therapy for hemophilia A.

Adenoviridae↗
PubMed1994

Weaning-food viscosity and energy density: their effects on ad libitum consumption and energy intakes in Jamaican children.

The effects of weaning-food viscosity and energy density on consumption and energy intake were determined in 15 non-breast-fed Jamaican children aged 7-15 mo under standardized conditions. We tested whether feeding thick, energy-dense porridge four times daily resulted in increased energy intakes and whether amylase treatment to reduce viscosity offered any advantage. When a traditional liquid, low-density porridge (2.15 kJ/g) was fed, the mean (+/- SD) daily consumption was 139 +/- 25 g/kg and the mean daily energy intake was 296 +/- 54 kJ/kg. When a semisolid high-density porridge (4.09 kJ/g) was fed, consumption was significantly lower (98 +/- 21 g/kg) but the daily energy intake was significantly higher--402 +/- 85 kJ/kg (P < 0.001). Amylase treatment of the thick energy-dense porridge did not increase intakes further. Meal duration for the thick porridge (12.9 +/- 4.0 min) was significantly longer than that for the low-density (7.4 +/- 2.6 min) or amylase-treated (6.4 +/- 1.8 min) porridges.

Amylases↗
PubMed1994

The mouse pink-eyed dilution gene: association with hypopigmentation in Prader-Willi and Angelman syndromes and with human OCA2.

Mutations at the mouse pink-eyed dilution locus, p, cause hypopigmentation. We have cloned the mouse p gene cDNA and the cDNA of its human counterpart, P. The region of mouse chromosome 7 containing the p locus is syntenic with human chromosome 15q11-q13, a region associated with Prader-Willi syndrome (PWS) and Angelman syndrome (AS), both of which involve profound imprinting effects. PWS patients lack sequences of paternal origin from 15q, whereas AS patients lack a maternal copy of an essential region from 15q. However, the critical regions for these syndromes are much smaller than the chromosomal region commonly deleted that often includes the P gene. Hypopigmentation in PWS and AS patients is correlated with deletions of one copy of the human P gene that is highly homologous with its mouse counterpart. A subset of PWS and AS patients also have OCA2. These patients lack one copy of the P gene in the context of a PWS or AS deletion, with a mutation in the remaining chromosomal homologue of the P gene. Mutations in both homologues of the P gene of OCA2 patients who do not have PWS or AS have also been detected.

Albinism, Oculocutaneous↗
PubMed1992

The mouse pink-eyed dilution gene: association with human Prader-Willi and Angelman syndromes.

Complementary DNA clones from the pink-eyed dilution (p) locus of mouse chromosome 7 were isolated from murine melanoma and melanocyte libraries. The transcript from this gene is missing or altered in six independent mutant alleles of the p locus, suggesting that disruption of this gene results in the hypopigmentation phenotype that defines mutant p alleles. Characterization of the human homolog revealed that it is localized to human chromosome 15 at q11.2-q12, a region associated with Prader-Willi and Angelman syndromes, suggesting that altered expression of this gene may be responsible for the hypopigmentation phenotype exhibited by certain individuals with these disorders.

Amino Acid Sequence↗
PubMed1992

Genetic and molecular analysis of recessive alleles at the pink-eyed dilution (p) locus of the mouse.

Recessive mutant alleles at the pink-eyed dilution (p) locus on mouse chromosome 7 reduce pigmentation of both the coat and eyes. Here we describe the properties and complementation interactions of 10 p alleles, including 6 not previously reported. Several alleles that cause additional phenotypes affecting development, reproduction, and behavior were shown to be deletions by using DNA probes derived from the p region. An alignment of functional and marker-defined units is proposed, giving a linear complementation map that orders at least four functional loci. The characterization of a nested set of deletions around p will facilitate detailed molecular analyses of the genes and developmental functions associated with this part of the mouse genome.

Alleles↗
PubMed1992

Differences in salivary cortisol levels in cocaine-exposed and noncocaine-exposed NICU infants.

To assess whether cocaine exposure in utero affected adrenocortical responsiveness in the neonatal period, salivary cortisol levels were compared between noncocaine-exposed (n = 35) and cocaine-exposed (n = 11) healthy preterm infants just prior to hospital discharge. Cortisol levels were measured under three conditions: Basal--120 min after no disrupting event or behavioral distress; Noninvasive Stressor--30 min after a neurobehavioral examination; Invasive Stressor--30 min after a heel-stick procedure. There were no differences in Basal cortisol levels between the noncocaine-exposed and cocaine-exposed infants, but the cocaine-exposed infants had significantly lower levels in both the Noninvasive and Invasive Stressor conditions. The suppressed cortisol responding to stressful events in cocaine-exposed infants suggests that these infants may have decreased modulation capability to normally stressful events, which could underlie some of the subtle state regulation problems reported.

Adrenal Cortex↗
PubMed1990

Dietary intake and observed activity of stunted and non-stunted children in Kingston, Jamaica. Part II: Observed activity.

It is generally believed that activity levels are reduced in poorly nourished children. This may conserve energy, but may have a detrimental effect on mental development. However there are few data which support this hypothesis. No previous studies were found which looked at the activity levels of stunted children. In this study we modified the time and motion observation methods of Torun (1984) by using recording periods of 1 instead of 10 min. This significantly reduced the estimated time spent by young children in moderate and vigorous activities. Four hours of observing young children while they were awake, using the modified method, produced highly reliable data. The activity levels of a subsample of children described in part I were observed. The children were aged 12-24 months and were observed for 4 h on 2 d. Seventy-eight stunted children (height less than -2 SD of median, NCHS) were compared with 26 non-stunted children (height greater than -1 SD). The stunted children were significantly less active than the non-stunted children, although the difference in activity rating was small (3.4 per cent). They spent more time in light activities (P less than 0.001) and less time in moderate or vigorous activities (P less than 0.01). Both groups slept a similar amount. Using Torun's values for the energy cost of activities it appears unlikely that the reduced activity would conserve energy to a great extent, but it may still be of biological importance, since it is comparable to the energy cost of growth at this age. Activity levels increased with age but were not significantly related to weight for height.(ABSTRACT TRUNCATED AT 250 WORDS)

Child, Preschool↗
PubMed1989

Use of salivary cortisol measurements in young infants: a note of caution.

In order to investigate possible contamination of saliva samples with formula or breast milk obtained from young infants for cortisol assays, we measured cortisol concentrations in 3 common infant milk formulas and in breast milk before and after defatting and extraction using a commercial radioimmunoassay kit. Cortisol concentrations obtained prior to defatting and extraction were equal to or higher than (1.64-82.80 micrograms/dL) levels reported for salivary cortisol levels reported in newborn infants (0.09-2.08 micrograms/dL). Cortisol concentrations obtained after the defatting and extraction were lower (0.02-0.15 micrograms/dL), indicating that values obtained prior to defatting and extraction were due to cross-reacting substances as well as cortisol. As saliva samples are not routinely defatted or extracted prior to being assayed, high cortisol levels and interfering substances in formula and breast milk could contaminate salivary cortisol measurements in young infants. The present study suggests that appropriate controls should be taken when making salivary cortisol measurements in young infants to help ensure accurate results.

Humans↗
PubMed1988

Mapping of mouse gamma crystallin genes on chromosome 1.

Restriction fragments analysis of DNA from mouse-hamster somatic-cell hybrid clones revealed that a mouse gamma crystallin cDNA hybridized to genomic sequences located on mouse chromosome 1. Identification of restriction fragment length polymorphisms (RFLPs) in the gamma crystallin sequences of inbred strains of mice permitted the further localization of the gamma crystallin genes (Cryg) to the proximal region of chromosome 1 closely linked to the loci encoding isocitrate dehydrogenase (Idh-1), a low molecular weight (LM) crystallin protein polymorphism (Len-1), and fibronectin (Fn-1). A single recombinant was observed between Len-1 and an RFLP in the gamma crystallin gene family, consistent with the hypothesis that Len-1 is one of the several structural loci encoding gamma crystallin genes. Len-1 is probably located on the centromeric end of the Cryg gene family. Linkage of Idh-1, Cryg, and Fn-1 in mice extends the syntenic relationship of those loci to the human, bovine, and rodent genomes and may define a chromosomal region that is generally conserved among mammals. The map position of Cryg, near the eye lens obsolescence (Elo) locus, was confirmed by the discovery that the restriction fragment patterns of gamma crystallin sequences differed between strain C3H/HeJ and the congenic anophthalmic mutant strain, C3H.Elo. Therefore, the gamma crystallin genes were cotransferred with the mutant Elo gene in the derivation of C3H.Elo. The results establish that LEN-1 is a marker for the gamma crystallin gene family, position the gamma crystallin gene family relative to other markers on mouse chromosome 1, and provide additional evidence that the Elo mutation is encoded at a locus closely linked to the gamma crystallin gene cluster. This study found no evidence of recombination hot spots within the gamma crystallin gene cluster.

Animals↗
PubMed1987

Tolypocladium cylindrosporum (Deuteromycotina: Moniliales), a fungal pathogen of the mosquito Aedes australis. II. Methods of spore propagation and storage.

A laboratory fermenter was used to produce up to 12 l of infective Tolypocladium cylindrosporum blastoconidia in Sabouraud dextrose broth. Two media derived from coconuts were also demonstrated as suitable alternative systems for the production of viable blastoconidia. T. cylindrosporum conidia when dried at 37 degrees C and stored at 4 degrees C retained their viability for 10 months, but, when stored at 25 degrees C, the conidia lost viability after 2 months and blastoconidia did not survive the drying process. Distilled water suspensions were a simple, economic technique for the long-term storage of spores at both 4 and 25 degrees C. The adsorption of conidia onto silica gel crystals was a very suitable technique for the storage of stock culture material at 4 degrees C. The virulence, production and storage capabilities of both spore types were examined.

Aedes↗
PubMed1987

Tolypocladium cylindrosporum (Deuteromycotina: Moniliales), a fungal pathogen of the mosquito Aedes australis. III. Field trials against two mosquito species.

A blastoconidial preparation of the New Zealand isolate of T. cylindrosporum was tested in two field trials against larvae of the freshwater mosquito Aedes subalbirostris and the brackish water species Ae. australis. There was some reduction in the population of the Ae. subalbirostris larvae and larvae collected from the test pools exhibited signs of fungal infection when reared in the laboratory. In the brackish pools there was no observable decrease in the larval populations even though Ae. australis is the natural host of T. cylindrosporum [NZ]. Water volume fluctuations in the test pools were a major difficulty experienced when monitoring the results. Tests against field-collected non-target fauna indicated that T. cylindrosporum is non-specific in action. Species of daphnid, dixid larvae and copepods were all susceptible to infection at varying degrees.

Aedes↗
PubMed1986

Tolypocladium cylindrosporum (Deuteromycotina: Moniliales), a fungal pathogen of the mosquito Aedes australis. I. Influence of temperature, pH and salinity on the growth and sporulation of the fungus in the laboratory.

The New Zealand strain of Tolypocladium cylindrosporum was cultured on Sabouraud dextrose agar medium under varying regimes of growth conditions. The isolate exhibited good tolerances to temperature (4-35 degrees C), pH (3-10) and salinity (0-7% NaCl). Optimal vegetative growth and sporulation were recorded between a temperature range of 20-30 degrees C, pH of 5-6 and a salinity level of 0-2% NaCl. The North American isolate of the fungus showed similar tolerances, while the European isolate was less tolerant.

Aedes↗
PubMed1986

Field trials of Tolypocladium cylindrosporum against larvae of Aedes polynesiensis breeding in crab holes in Fiji.

The New Zealand isolate of the entomopathogenic fungus Tolypocladium cylindrosporum was field-tested against larvae of the crab hole breeding mosquito Aedes polynesiensis. A reduction of approximately 87% was achieved in the larval populations of all crab holes treated with T. cylindrosporum by day 21 of spore application. However, the mosquito populations recovered to the pretreatment level within two months indicating that any residual activity of this pathogen was insignificant.

Aedes↗
PubMed1985

Interaction of fibronectin with its receptor on platelets.

We report that the 12,000 dalton domain of fibronectin that interacts with fibroblast cell surfaces also binds specifically to thrombin-inducible, saturable receptors on platelets. Furthermore, we have used chemical cross-linking and monoclonal antibodies to show that the 12,000 dalton domain of fibronectin interacts directly with glycoprotein IIIa at the platelet cell surface. Both binding and cross-linking of this domain to platelets are competed by a hexapeptide previously shown to block fibroblast adhesion to fibronectin. Finally, we show that a complex of the platelet glycoproteins IIIa and IIb binds to affinity columns of a cell-attachment fragment of fibronectin. These results localize a major fibronectin-platelet interaction to a specific domain of fibronectin and to a specific platelet glycoprotein.

Antibodies, Monoclonal↗
PubMed1983

Fibronectin expression during myogenesis.

The biosynthesis and localization of fibronectin during chick muscle differentiation are described. This study employed two monoclonal antibodies, one that selectively killed mononucleated cells and one specific for avian fibronectin. These antibodies allowed precise analyses of fibronectin expression in well-defined cultures of myoblasts or myotubes and avoided the complications of exogenous fibronectin and contamination by fibroblasts or unfused myoblasts. Fibronectin synthesis, as a fraction of total protein synthesis, remains constant at 0.3-0.4% before and after myoblast fusion, suggesting that the absolute rate of fibronectin synthesis may increase somewhat when myotubes synthesize and accumulate myofibrillar proteins. The pattern of fibronectin arrangement does change during myogenesis. In myotube cultures, the appearance of pulse-labeled fibronectin at the cell surface and its secretion into the medium begin after a 2-3-h lag period, in contrast to the 30-min lag period observed in fibroblast cultures. This lag between polypeptide biosynthesis and the exteriorization of the new protein is thus a characteristic of each cell type rather than the protein. All of the major secretory proteins of myogenic cells, including fibronectin and collagenous components, share this 2-3-h intracellular transit time.

Animals↗