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Biomedical subjects

G Jones

Publications and source records attributed to G Jones.

At least 307 records · Page 17Linked to original sources
PubMed1994

Air quality and respiratory functioning in children with pulmonary disorders.

This study was conducted to examine the relation between daily ambient air conditions, contaminants (eg, aeroallergens such as mold spores and pollen), and respiratory health indices of children with respiratory disorders (eg, asthma) residing in metropolitan Baton Rouge, Louisiana. Daily measures of peak expiratory flow rate (PEFR), respiratory symptoms, and other indices of health were monitored as subjects went about their normal daily activities. The results of this study suggest that high summer temperatures had the greatest impact on children's health status and activity level, with humidity and mold counts also contributing significantly to a decline in respiratory health indices.

Adolescent↗
PubMed1994

Epidural analgesia for effective pain control.

Over the past decade, awareness of the harmful effects of postoperative pain has increased. These effects seem to be intensified in critically ill patients. Epidural analgesia has been shown to improve pulmonary function in the critically ill, including a reduction in frequency of intubation and tracheostomies and decreased length of mechanical ventilatory support. In addition, the heightened metabolic-stress response associated with pain may be averted, thereby reducing problems with fluid retention that may further compromise pulmonary status. As a result, epidural analgesia can lead to: shortened length of stay in the ICU overall decreased mortality rate improvement in quality of life As a pain-control method, epidural analgesia is gaining popularity in a variety of ICU patient populations. Therefore, critical care nurses need to update their knowledge base and nursing practice to provide safe and effective nursing care. State nurse practice acts and agency policies dictate the amount and type of involvement nurses have in caring for patients receiving epidural pain therapy. Potential life-threatening problems with epidural analgesia are rare. Many side effects can be controlled or prevented with appropriate patient selection and nursing management.

Analgesia, Epidural↗
PubMed1994

Why I choose autogenous tissue in breast reconstruction.

The history of autogenous breast reconstruction is outlined followed by a review of the problems associated with prosthetic reconstructive techniques. The advantages of and indications for autogenous tissue reconstruction are highlighted and illustrated with clinical examples.

Female↗
PubMed1993

Prediction of osteoporotic fractures by postural instability and bone density.

OBJECTIVE: To investigate the utility of risk factors such as bone mineral density, lifestyle, and postural stability in the prediction of osteoporotic fractures. DESIGN: Longitudinal, epidemiological, and population based survey. SETTING: City of Dubbo, New South Wales. SUBJECTS: All residents of Dubbo aged > or = 60 on 1 January 1989. MAIN OUTCOME MEASURE: Incidence of fracture for individual subjects. RESULTS: The overall incidence of atraumatic fractures in men and women was 1.9% and 3.1% per annum respectively. The predominant sites of fracture were hip (18.9%), distal radius (18.5%), ribs and humerus (11.9% in each case), and ankle and foot (9.1% and 6.6% respectively). Major predictors of fractures in men and women were femoral neck bone mineral density, body sway, and quadriceps strength. Age, years since menopause, height, weight, and lifestyle factors were also correlated with bone mineral density and body sway and hence were indirect risk factors for fracture. Discriminant function analysis correctly identified 96% and 93% (sensitivities 88% and 81%) of men and women, respectively, who subsequently developed atraumatic fractures. Predictions based on this model indicated that a woman with a bone mineral density in the lowest quartile in the hip together with high body sway had a 8.4% probability of fracture per annum. This represented an almost 14-fold increase in risk of fracture compared with a woman in the highest bone mineral density quartile with low postural sway. An individual with all three predictors in the "highest risk" quartile had a 13.1% risk of fracture per annum. CONCLUSIONS: Bone mineral density, body sway, and muscle strength are independent and powerful synergistic predictors of fracture incidence.

Aged↗
PubMed1993

Transfected human liver cytochrome P-450 hydroxylates vitamin D analogs at different side-chain positions.

A full-length cDNA for the human liver mitochondrial cytochrome P-450 CYP27 was cloned from a human hepatoma HepG2 cDNA library and then subcloned into the mammalian expression vector pSG5. When CYP27 cDNA was transfected into COS-1 transformed monkey kidney cells along with adrenodoxin cDNA, transfected cells revealed a 10- to 20-fold higher vitamin D3-25-hydroxylase activity than nontransfected cells. Transfected cells were capable of 25-hydroxylation of vitamin D3, 1 alpha-hydroxyvitamin D3 and 1 alpha-hydroxydihydrotachysterol3. In each case they also showed the ability to 26(27)-hydroxylate the cholesterol-like (D3) side chain. The relative rates of 25- and 26(27)-hydroxylation of 1 alpha-hydroxyvitamin D3 approximately mimicked the ratio of products observed in HepG2 cells. Vitamin D2 and 1 alpha-hydroxyvitamin D2, both with the ergosterol-like side chain, were 24- and 26(27)-hydroxylated by CYP27. The rate of side-chain 24-, 25-, or 26(27)-hydroxylation was greater for 1 alpha-hydroxylated vitamin D analogs than for their nonhydroxylated counterparts. We conclude that CYP27 is capable of 24-, 25-, and 26(27)-hydroxylation of vitamin D analogs and that the nature of products is partially dictated by the side chain of the substrate. This work has revealed that the cytochrome P-450 CYP27 may be important in the metabolism of vitamin D analogs used as drugs.

Animals↗
PubMed1993

Echolocation calls of bats are influenced by maternal effects and change over a lifetime.

The greater horseshoe bat, Rhinolophus ferrumequinum, is a model species in echolocation studies, and emits calls containing long constant-frequency (CF) components. The bats have auditory systems tuned sharply to frequencies close to the resting CF (RF) values. Call frequency and neural processing are both flexible within individual bats which use this mode of echolocation. The simple structure of the calls makes them ideal for sonographic analysis. Here, in a large-scale and long-term analysis of changes in the vocalizations of bats we show that: (i) the calls of R. ferrumequinum aged 1-28 years vary seasonally and over a lifetime in a predictable manner; and (ii) an infant's RF is at least partly determined by the RF of its mother. We consider the relative importance of genetic and learning factors upon the correlation between RFS of mothers and offspring.

Aging↗
PubMed1993

Identification of a chemotactic domain of the pro-inflammatory S100 protein CP-10.

We previously reported the purification and partial amino acid sequence of a novel murine cytokine designated CP-10, which has chemotactic activity for murine polymorphonuclear cells (PMN) and macrophages. The complete cDNA encoding an 88-amino acid polypeptide has been isolated and the sequence is presented here. Transient transfection of CP-10 cDNA into CV-1 cells confirmed the chemotactic activity of rCP-10 for murine PMN. CP-10 has sequence homology with members of the S100 family of Ca(2+)-binding proteins with pronounced amino acid sequence similarities within the putative N- and C-terminal Ca(2+)-binding sites, but differences within their connecting hinge and C-terminal regions. We have confirmed the hypothesis of Kligman and Hilt that functional specificity of individual members of the S100 protein family may reside in the hinge region. A synthetic peptide corresponding to the hinge region of CP-10 (CP-10(42-55) was compared with native CP-10 in chemotaxis and skin test assays. Native CP-10 had potent activity for phagocytic cells, but not lymphocytes, in vitro (optimal activity, 10(-11) to 10(-13) M) and elicited a sustained recruitment of neutrophils and mononuclear cells over 24 h in vivo. The hinge-region peptide had strong chemotactic activity for murine phagocytic cells (optimal activity, 10(-10) - 10(-11) M) but elicited only a transient infiltration of neutrophils over 4 to 8 h after intradermal injection. Results indicate that although the hinge region contributes significantly to the functional specificity of the S100 protein CP-10, sustained cellular recruitment typical of a delayed type hypersensitivity response is apparently dependent on the structural integrity of the protein.

Amino Acid Sequence↗
PubMed1993

Rubella surveillance to December 1992: second joint report from the PHLS and National Congenital Rubella Surveillance Programme.

The high uptake of measles/mumps/rubella vaccine since October 1988 has had a major impact on rubella susceptibility in children under five years of age, with interruption of the epidemic cycle and reduction in incidence to a low endemic level. The number of infections in pregnancy reported in England and Wales to the PHLS Communicable Disease Surveillance Centre fell to 23 in 1990, and to 12 and two, respectively, in 1991 and 1992. The reduction was greatest in parous women, a group who were previously at risk through exposure to their own children. During 1991, however, susceptibility in parous antenatal women rose from 0.7% to 1%, suggesting that post-partum immunisation rates may have declined recently. If continued, this could give rise to outbreaks of congenital rubella in the future during the brief periods of rubella resurgence expected before disease elimination is achieved. Susceptibility among Asian women was four times higher than among non-Asians. Of the total of 94 births of congenitally infected infants since January 1987, only 19 occurred during 1990-92 (but this may increase due to late diagnoses). Factors contributing to the continuing occurrence of congenital rubella include missed opportunities for immunisation at school or post-partum, maternal reinfection, and recent immigration into the United Kingdom. Twenty-two (24%) of the women giving birth to congenitally infected infants since 1987 were Asian or Oriental women, of whom at least three acquired their infections abroad. Imported cases will be distinguished in future surveillance reports.

Abortion, Eugenic↗
PubMed1993

Bimodal echolocation in pipistrelle bats: are cryptic species present?

The pipistrelle bat Pipistrellus pipistrellus is the most widespread in Europe, and is often the most abundant bat species in northern and central Europe. P. pipistrellus has traditionally been considered as one species throughout Europe. Here we show that: (i) the echolocation calls of pipistrelles fall into two distinct frequency bands in Britain, with frequencies containing most energy averaging 46 kHz and 55 kHz; (ii) roosts consist of bats which use only one form of echolocation; (iii) small but significant differences in average gross morphology exist between the phonic types; and (iv) the two phonic types occur in sympatry over much of Britain. Recordings made from European populations show that bimodal echolocation is also typical of continental pipistrelles, with only one phonic type found in some areas, two types in sympatry in others. The sympatric occurrence of two phonic types, the lack of mixing of types between colonies, and the morphological divergence between phonic types suggests that P. pipistrellus may actually consist of at least two cryptic sibling species. The evolution of bimodal echolocation in bats is discussed, and a model involving disruptive selection is presented to show how sympatric speciation may occur.

Acoustics↗
PubMed1993

Characterization of two major isoforms of juvenile hormone esterase from Trichoplusia ni (Lepidoptera).

The two major isoforms of juvenile hormone (JH) esterase isolated from Trichoplusia ni were fragmented by cyanogen bromide and trypsin digestion. The resulting CNBr or CNBr/trypsin fragments were characterized and compared biochemically by SDS-PAGE, isoelectric focusing, two-dimensional electrophoresis and HPLC. Similar and unique fragments were examined for sequence, antigenic determinants and carbohydrate moieties. The studies identified small regions of the proteins which possess either potentially different sequences or different post-translational modifications. The location of a glycosylated asparagine residue was determined, as well as a region containing an epitope probably composed of a linear sequence of residues. An N-terminal region was identified that contained charge variation between the two isoforms and the sequence was obtained for the only unique CNBr/trypsin fragment detected from that region. These are the first data on mapping of regions of charge variation, epitope location and glycosylation sites for this enzyme from any insect species.

Amino Acid Sequence↗
PubMed1993

Hormonal regulation and properties of a new group of basic hemolymph proteins expressed during insect metamorphosis.

Two abundant basic proteins, and arylphorin, that are expressed during metamorphosis of Trichoplusia ni were isolated, their cDNAs cloned, and regulation of their expression assessed. According to the criteria of encoded protein sequence, positions of sequence coinitiation and cotermination, amino acid compositions, nonsex-specificity, and immunological analyses, the related yet distinct basic proteins do not correspond to any previously established group of insect proteins, each of which can be distinguished on the basis of such criteria, although they appear to be within the arthropod hemocyanin superfamily. The basic proteins can be separated under native isoelectric focusing conditions, indicating that they do not preferentially form heteromeric complexes under such conditions. While the transcripts for both basic proteins and a coexpressed acidic protein (Jones, G., Brown, N., Manczak, M., Hiremath, S., and Kafatos, F. (1990) J. Biol. Chem. 265, 8596-8602) appeared in both sexes on the day prior to ecdysteroid-driven metamorphic commitment, and persisted at high abundance for the next 24 h, the arylphorin mRNA appeared 1 day earlier and declined immediately after metamorphic commitment. The dynamics of suppression of the appearance and abundance of transcripts in response to maintenance of a high juvenile hormone titer was different for the acidic versus the two basic proteins. Another regulatory difference in response to juvenile hormone was shown by a decreased translatability of the mRNAs for the two basic proteins, but not for the acidic protein. In contrast, the abundance and translatability of arylphorin mRNA was insensitive to a high juvenile hormone level. A further difference in regulation was shown by the maintenance of a high level of both arylphorin and the acidic protein in the hemolymph after disappearance of their transcripts, while the basic proteins instead disappeared from the hemolymph and persisted in the fat body. These results establish at least three qualitatively different effects of juvenile hormone on the abundance of transcripts for these representatives of three groups in the hemocyanin superfamily, and also establish mRNA translatability as another differential level of regulation among them. Given these differences in mechanisms of regulation of evolutionarily related proteins, this system of metamorphosis-associated proteins in T. ni should prove to be a valuable tool in studies of mechanisms of hormonal regulation of gene expression during the metamorphic transformation of larval tissues.

Adipose Tissue↗
PubMed1993

In vivo metabolism of the vitamin D analog, dihydrotachysterol. Evidence for formation of 1 alpha,25- and 1 beta,25-dihydroxy-dihydrotachysterol metabolites and studies of their biological activity.

Dihydrotachysterol (DHT), a reduced vitamin D analog in which the A-ring has been rotated through 180 degrees is a biologically active molecule which can be used to study the structural requirements for the calcemic and cell differentiating properties of the vitamin D hormone, 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25-(OH)2D3), as well as to investigate the specificity of the enzyme systems that catalyze the formation of this hormone. In this study we showed that dihydrotachysterol was metabolized in vivo into a significant polar metabolite observed on straight-phase high performance liquid chromatography (HPLC) which subsequently split into two peaks on reverse-phase HPLC. These two metabolites were identified by HPLC and gas chromatography-mass spectrometry techniques as 1 alpha,25-(OH)2DHT and 1 beta,25-(OH)2DHT. This pair of metabolites was formed from either DHT2 or DHT3. Standard 1 alpha,25-(OH)2DHTs were generated in vitro from chemically synthesized 1-hydroxydihydrotachysterol precursors using a liver hepatoma cell system. Both 1 alpha,25-(OH)2D2 and 1 alpha,25-(OH)2DHT3 showed a binding affinity to the mammalian vitamin D receptor only 50-100 less than 1 alpha,25-(OH)2D3 whereas 1 beta,25-(OH)2DHTs showed poor binding. On the other hand 1 beta,25-(OH)2DHT3 bound to the rat vitamin D transport protein (DBP) with stronger affinity than did 1 alpha,25-(OH)2DHT3. When tested in a COS-1 cell transfection assay system using a rat osteocalcin vitamin D responsive element coupled to a growth hormone reporter gene, 1 alpha,25-(OH)2DHT3 showed a biological activity only 10 times lower than 1 alpha,25-(OH)2D3. It is therefore suggested that 1 alpha,25-(OH)2DHT probably represents the metabolite of DHT responsible for some of its in vivo effects although we cannot rule out in vivo effects of other metabolites identified. Our studies suggest that 1 alpha,25-dihydroxylated DHTs represent a promising novel group of vitamin D analogs worthy of study for cell differentiation as well as calcemic properties.

Animals↗
PubMed1993

Basic isoforms of hemolymph storage proteins expressed during larval metamorphosis.

The hemolymph of metamorphosing, final instar larvae of Trichoplusia ni was analyzed for the presence of basic forms of normally positively charged storage proteins. Basic forms of arylphorin and a normally acidic juvenile hormone suppressible protein were identified. For each of these two proteins, variation was observed in the immunoreactivity of forms with different basic charges, where the antisera had been generated against acidic forms of each protein. A basic protein of high molecular size (ca. M(r) 150,000) was identified that cross-reacted specifically with an antiserum raised against a normally basic, M(r) 74,000 juvenile hormone suppressible protein in the hemocyanin superfamily.

Animals↗
PubMed1993

Juvenile hormone action to suppress gene transcription and influence message stability.

Proteins normally expressed in high abundance only at larval-pupal metamorphosis in Trichoplusia ni were examined in a comparative analysis of the role and level of hormonal control of their expression. Some related proteins in the hemocyanin-superfamily (i.e., an acidic protein [AJHSP1] and two basic proteins [BJHSP1, BJHSP2]) were shown by nuclear run-on analysis to be specifically transcriptionally suppressed by juvenile hormone (JH), while transcription of another member of that family which is also metamorphosis-associated (arylphorin) was not specifically sensitive to JH. The stability of the mRNA for those members transcriptionally down-regulated by JH appeared to decrease under high JH conditions. While each protein was resorbed to some extent by the prepupal fat body, only the two basic proteins were quantitatively cleared from prepupal hemolymph. The JH-sensitive proteins studied appear to be encoded in single copy genes not immediately juxtaposed in the genome. These and previous studies now permit a more comprehensive understanding of the different combinations of mechanisms involving transcription, mRNA stability, translation, and protein clearance that operate to regulate these metamorphosis-associated proteins.

Animals↗
PubMed1993

Reduced creatinine clearance in primary osteoporosis in women.

We determined the relationship between bone mass and age, anthropometric variables, and serum and urine biochemical variables in 77 normal white women and 37 women with primary osteoporosis, 25 of whom had one or more vertebral compression fractures. Skeletal status was assessed by radiography of the hands with measurement of combined cortical thickness of the second metacarpal bones (CCT) or measurement of radial and lumbar bone density, or by both methods. Radial bone mineral content (RBMC) was measured by single-photon absorptiometry (SPA) and lumbar bone mineral density by dual-photon absorptiometry (DPA). Serum and urine biochemical variables were measured on days 6 and 7 of a controlled diet. In this mixed population of normal and osteoporotic women, we confirmed the strong positive correlation between creatinine clearance (Ccr) and bone mass that we previously reported in normal women. Multiple regression analysis showed that the relationship between Ccr and bone mass of the radius and lumbar spine was independent of age and body stature. Ccr was significantly lower in the 25 osteoporotic women with vertebral crush fractures than in age-matched normal women, and Ccr had predictive value for bone mass in individual subjects. The basis for the relationship between Ccr and bone mass has not been established. We excluded diminished production of 1,25-dihydroxyvitamin D as a result of declining renal function as a possible mechanism.

Absorptiometry, Photon↗