PubMed Health⌕ Search

Biomedical subjects

G Grove

Publications and source records attributed to G Grove.

16 recordsLinked to original sources
PubMed2000

Whole body protein turnover can be measured non-invasively in women using the end product method with [15N]glycine to show changes with the menstrual cycle and pregnancy.

OBJECTIVES: To assess the effect of the menstrual cycle and pregnancy on whole body protein turnover. DESIGN AND SUBJECTS: Whole body protein turnover was determined using oral [15N]glycine in normal women from enrichment measured in urine at days 7 and 14 of the menstrual cycle and in pregnant women at 17-20 weeks and 30-32 weeks gestation. RESULTS: Nitrogen flux was 38.2 (5.8) mg N/kg/h using a single dose and 31.1+/-4.1 mg N/kg/h with prime-intermittent doses-the same as in men using the same methods. Nitrogen flux around the time of ovulation, 32.3 (8.2) mg N/kg/h, was greater than at day 7, 26.8 (3.0) mg N/kg/h (P<0.05). For women taking the contraceptive pill flux at day 7, 22.7 (0.2) mg N/kg/h, and day 14, 21.3 (2.1) mg N/kg/h, were similar, but were lower at day 14 than for women not taking the pill (P<0.05). Protein synthesis increased between mid and late pregnancy (1.7-2.0 g N/h; P=0.012), but not when expressed in relation to body weight CONCLUSIONS: Protein turnover can be measured reproducibly in women using a non-invasive method, provided care is taken to standardize the conditions, and especially the duration over which urine is collected. There is an increase around the time of ovulation when hormonal levels are at their highest and during pregnancy the results obtained are similar to those reported using [13C]leucine. SPONSORSHIP: University of Southampton and Medical Research Council.

Administration, Oral↗
PubMed1997

Enrichment in urinary ammonia and urea with hourly oral doses of [15N]glycine: evidence for a step function and a circadian rhythm in protein turnover.

1. The present study sought to determine the possible existence of a pool of proteins which turn over with life-time kinetics. The pattern of enrichment of ammonia and urea in hourly samples of urine was determined in normal adults to whom oral doses of [15N]glycine were given hourly for 36 h. The subjects received hourly meals throughout, and in six the study commenced at 06.00 hours, in five at 12.00 hours and in two at 18.00 h. 2. A plateau level of enrichment was achieved in urinary ammonia within 4-6 h. Regardless of the time at which the study started this plateau was held until about midnight, at which time there was an increase in enrichment, with a second higher plateau 5-6 h later. The second plateau was held to the end of the study. For urinary urea the rate of rise in enrichment was slower and smoother, because of the slow turnover of the urea pool. 3. Protein synthesis, derived from the first ammonia plateau, 179 mg h-1 kg-1, was significantly higher than that derived from the second plateau, 118 mg h-1 kg-1. Using the plateau in urea towards the end of the 36 h, the estimate of protein synthesis was 153 mg h-1 kg-1. 4. The results are considered to provide evidence of a pool of proteins for which degradation takes place in harmony with a circadian rhythm.

Adult↗
PubMed1997

The neuroanatomy of 5-HT dysregulation and panic disorder.

The advent of highly effective antipanic medications with specific serotonin reuptake inhibition as a mechanism of action has prompted the need for new pathophysiological models of panic disorder. The authors attempt an integration of the emerging basic science literature regarding the neuro-anatomy and physiology of the mammalian central serotonin nervous system, its influence on neural substrates that underlie fear and defense responses, and the clinical literature pertaining to serotonin-related abnormalities in panic disorder. A neuro-anatomical model for the potential sites of action of the specific serotonin reuptake inhibitors in panic disorder is proposed.

Afferent Pathways↗
PubMed1996

Short contact 70% glycolic acid peels as a treatment for photodamaged skin. A pilot study.

BACKGROUND: Glycolic acid has been one of the more commonly used alpha hydroxy acids for the treatment of photodamaged skin. Its value as a quick "skin refreshing" peeling agent has been widely touted. This type of peel differs from a conventional therapeutic peel (eg, phenol, trichloroacetic acid, or a longer time exposure alpha hydroxy acid peel) in that there is little skin reaction and patients can go about their daily routine without concern. OBJECTIVE: To assess the potential value of glycolic acid-based refresher peels as a cosmetic procedure. METHODS: Twelve healthy subjects with at least a moderate degree of photodamage were treated with monthly serial 70% glycolic acid peels over a period of 4 months. In addition to the "peels," six subjects were randomized to a 10% glycolic acid-based moisturizer twice daily. Patients were evaluated monthly and graded on a clinical scale using objective measures. RESULTS: No conclusive differences were noted on histologic evaluation. Ninety percent (9/10) of patients felt that overall they noticed significant improvement, however, there was no distinction between the two treatment options. The improvement in fine wrinkling and pigmentation was primarily seen in the patients who additionally received 10% glycolic emollient twice daily. CONCLUSION: In this limited pilot study, no specific benefit could be assigned to the concomitant use of monthly glycolic acid refresher "peels" in the treatment of photodamaged skin.

Adult↗
PubMed1995

Measurement of protein turnover in normal man using the end-product method with oral [15N]glycine: comparison of single-dose and intermittent-dose regimens.

The 'single-dose end-product' approach for the measurement of protein turnover is the only method suited for application to free-living individuals and for field studies. However, the method has never been widely accepted because the results obtained appear to vary from one situation to another. There is the need for a formal comparison of the different approaches that have been used and the assumptions on which they are based in order to be able to understand the extent to which the variation in the results obtained is real or might be attributed to methodological differences. The present study used the 'prime/intermittent-dose end-product' approach over 18 h as a reference with which to compare the 'single-dose end-product' approach, with urine being collected for periods of 9 to 48 h. N flux was derived in a total of thirteen normal men using oral [15N]glycine and measurement of 15N enrichment in urinary NH3 or urea, with isotope being given either as prime/intermittent doses or a single dose in separate studies. The pattern of results was similar to those reported in the literature. In all studies the rates of N flux derived from urea were higher than those derived from NH3, under equivalent conditions, by about 25-30%. The single-dose approach, with urine collection over 9 h, gave results which were consistently higher than the prime/intermittent-dose approach. The extent of the difference was influenced by the duration of time over which the cumulative excretion of isotope in urine was determined, and with NH3 as the end-product the most consistent estimates of N flux could be obtained with a urine collection of at least 12 h and no greater than 24 h. With urea as the end-product, correction for the label retained in the body pool at 9 h gave similar results for N flux to those derived from the total excretion of label in urea over 24 h. The derivation of values for protein synthesis and protein degradation from measures of flux requires care to ensure that the time periods over which N intake and excretion are measured accord with those for which the measurement of flux apply. It is concluded that measurements of protein turnover similar to those obtained with the prime/intermittent-dose approach can be obtained with the single-dose approach in the fed state during the daytime, either from the excretion of label in urinary NH3 over a period of 12 h or with the excretion of label in urinary urea over a period of 24 h. The suitability of the method for use in the fasted state or at night time remains to be determined.

Adult↗
PubMed1989

Stratum corneum lipids in skin xerosis.

Lipids of the stratum corneum are implicated in cohesion and desquamation of the stratum corneum as well as in the maintenance of normal barrier function. Evidence linking the intercellular lipids to such processes has mainly been derived from studies on acquired or inherited diseases of lipid metabolism manifesting abnormalities in the structure and the function of the stratum corneum. We have studied the composition of stratum corneum lipids in clinically normal individuals with typical xerosis or 'winter dry skin' in order to establish if the lipid composition differs from that of normal individuals, showing no signs of xerosis. The amount of total stratum corneum lipids was not related to xerosis (22.0 +/- 1.8 micrograms/cm2 for normal skin, and 26.3 +/- 2.9 micrograms/cm2 for severe xerosis), and no correlation was evident between polar lipids, cholesterol sulfate (2.8 +/- 0.5% for normal skin, and 1.6 +/- 0.2% for severe xerosis), or ceramides types I-VI, and dry skin. It therefore appears that dramatic changes in stratum corneum lipids are not detectable in normal 'winter dry' skin. However, a decreased proportion of neutral lipids (sterol esters, triglycerides), coupled to increased amounts of free fatty acids, were found associated to the severity of dry skin. Apart from a decline in the sebaceous function and in esterases activity, winter dry skin does not appear to be associated to dramatic changes in polar stratum corneum lipids.

Adult↗
PubMed1988

Gene expression of rat glutathione S-transferases. Evidence for gene conversion in the evolution of the Yb multigene family.

We have characterized a cDNA with complete coding sequence for the rat liver glutathione S-transferase subunit 4 (Yb2) isolated from a constructed lambda gt10 cDNA library. Functional expression of the cDNA sequence has resulted in the purification to homogeneity of an enzymatically active anionic glutathione S-transferase. In addition to three previously described Yb-type subunits (Yb1, Yb2, Yb3), we now report characterization of a fourth Yb subunit sequence in the form of a genomic DNA clone lambda GTR15-2. The Yb4 gene has no apparent defect, and the deduced Yb4 polypeptide sequence differs from the other three Ybs by 40 to 53 amino acids. The Yb4 gene organization is similar to that of the Yb2 gene in having a minimum of eight exons. Three out of the seven introns between the two genes are conserved to the extent of more than 88% nucleotide identity. We propose that gene conversion may have played a role in the evolution of these Yb genes.

Amino Acid Sequence↗
PubMed1988

Characterization and heterospecific expression of cDNA clones of genes in the maize GSH S-transferase multigene family.

We have isolated from a constructed lambda gt11 expression library two classes of cDNA clones encoding the entire sequence of the maize GSH S-transferases GST I and GST III. Expression of a full-length GST I cDNA in E. coli resulted in the synthesis of enzymatically active maize GST I that is immunologically indistinguishable from the native GST I. Another GST I cDNA with a truncated N-terminal sequence is also active in heterospecific expression. Our GST III cDNA sequence differs from the version reported by Moore et al. [Moore, R. E., Davies, M. S., O'Connell, K. M., Harding, E. I., Wiegand, R. C., and Tiemeier, D. C. (1986) Nucleic Acids Res. 14:7227-7235] in eight reading frame shifts which result in partial amino acid sequence conservation with the rat GSH S-transferase sequences. The GST I and GST III sequences share approximately 45% amino acid sequence homology. Both the GST I and the GST III mRNAs contain different repeating motifs in front of the initiation codon ATG. Multiple poly(A) addition sites have been identified for these two classes of maize GSH S-transferase messages. Genomic Southern blotting results suggest that both GST I and GST III are present in single or low copies in the maize (GT112 RfRf) genome.

Amino Acid Sequence↗
PubMed1986

Cloning and sequence analysis of a cDNA for a rat liver glutathione S-transferase Yb subunit.

We have isolated a Yb-subunit cDNA clone from a GSH S-transferase (GST) cDNA library made from rat liver polysomal poly(A) RNAs. Sequence analysis of one of these cDNA, pGTR200, revealed an open reading frame of 218 amino acids of Mr = 25,915. The deduced sequence is in agreement with the 19 NH2-terminal residues for GST-A. The sequence of pGTR200 differs from another Yb cDNA, pGTA/C44 by four nucleotides and two amino acids in the coding region, thus revealing sequence microheterogeneity. The cDNA insert in pGTR200 also contains 36 nucleotides in the 5' noncoding region and a complete 3' noncoding region. The Yb subunit cDNA shares very limited homology with those of the Ya or Yc cDNAs, but has relatively higher sequence homology to the placental subunit Yp clone pGP5. The mRNA of pGTR200 is not expressed abundantly in rat hearts and seminal vesicles. Therefore, the GST subunit sequence of pGTR200 probably represents a basic Yb subunit. Genomic DNA hybridization patterns showed a complexity consistent with having a multigene family for Yb subunits. Comparison of the amino acid sequences of the Ya, Yb, Yc, and Yp subunits revealed significant conservation of amino acids (approximately 29%) throughout the coding sequences. These results indicate that the rat GSTs are products of at least four different genes that may constitute a supergene family.

Amino Acid Sequence↗
PubMed1984

Age differences in poison ivy dermatitis.

In both man and animals, cell-mediated immunity diminishes with advanced age. Because poison ivy is a very common allergy, we evaluated age-associated differences in the contact allergic reaction to Rhus. Oleoresin patch tests were applied to two age cohorts (18-25 versus 65-84) each of 14 healthy white subjects. In the elderly, the allergic reaction developed more slowly, the inflammatory response at peak was greatly diminished and the dermatitis lasted longer and seemed to be more pruritic.

Adolescent↗
PubMed1981

Identification of the product of the major regulatory gene of the nitrogen control circuit of Neurospora crassa as a nuclear DNA-binding protein.

The nitrogen regulatory circuit of Neurospora crassa contains an entire set of unlinked structural genes which specify nitrogen catabolic enzymes. These genes are controlled as a group by a major regulatory gene, designated nit-2, which "turns on" their expression in a positive fashion. Moreover, expression of these same structural genes is repressed when the cells contain sufficient nitrogen; the active repressor metabolite has been identified as glutamine. It has been suggested that the nit-2 gene product is a protein which binds at a recognition sequence near each nitrogen-related structural gene to activate their expression. We have directly examined the nuclear proteins of Neurospora in order to attempt to detect th postulated nit-2 regulatory protein. Nonhistone nuclear proteins were isolated, labeled in vitro, and applied to DNA-cellulose and subsequently specifically eluted with glutamine. A single protein, whose molecular weight is approximately 22,000, was eluted from DNA-cellulose by glutamine but not by asparagine. This same protein was greatly reduced in quantity in the nonhistone proteins isolated from two nit-2 mutants; a third nit-2 mutant has a normal amount of this nuclear protein but it displays a slightly higher electrophoretic mobility than found in wild type. Finally, a revertant of a nit-2 mutant possesses approximatley 20 times as much of this protein as does the parental nit-2 mutant, an amount essentially equivalent to that found in wild type. The results suggest that the nit-2 control gene encodes this DNA-binding protein, which is postulated to play a major role in regulating expression of the structural genes of the nitrogen control circuit of Neurospora.

Carrier Proteins↗
PubMed1980

Nitrogen regulation of acid phosphatase in Neurospora crassa.

Neurospora crassa possesses a repressible acid phosphatase with phosphodiesterase activity which appears to permit it to utilize ribonucleic acid as a phosphorus and as a nitrogen source. This acid phosphatase, which is specified by the pho-3 locus, is derepressed approximately eightfold during nitrogen limitation and to an even greater extent during phosphorus limitation, but is unaffected by sulfur limitation. Derepression of the enzyme did not occur when adenosine 5'-monophosphate was the sole phosphorus or nitrogen source. Synthesis of the acid phosphatase is not under the control of the nit-2 locus, which regulates the expression of a large number of other nitrogen catabolic enzymes. The structural gene of the acid phosphatase appears to be a member of both the phosphorus and nitrogen regulatory circuits.

Acid Phosphatase↗