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Biomedical subjects

A Prentice

Publications and source records attributed to A Prentice.

At least 127 records · Page 7Linked to original sources
PubMed1993

Immunohistochemical localization of acidic and basic fibroblast growth factors in normal human endometrium and endometriosis and the detection of their mRNA by polymerase chain reaction.

Growth factors play a role in the cyclical growth and vascularization of normal endometrium. Abnormal endometrial proliferation and neovascularization may result in endometriosis. This study determines the presence and localization of acidic and basic fibroblast growth factors (aFGF and bFGF respectively) in endometrium of normal women, and in normal and ectopic endometrium of women with endometriosis. Endometrium was obtained at curettage or hysterectomy for benign disease, or laparoscopy for endometriosis. aFGF- and bFGF-immunoreactivity was detected at different phases of the menstrual cycle by immunohistochemistry using primary polyclonal rabbit antibodies. Expression of mRNA for aFGF and bFGF was determined in normal endometrium by nested reverse transcriptase polymerase chain reaction (RT-PCR). aFGF- and bFGF-immunoreactivity were both detected in endometrium from normal women, and in normal and ectopic endometrium of women with endometriosis. The pattern of staining with the two different FGFs was the same: immunoreactivity was predominantly confined to glandular epithelial cells and did not change throughout the menstrual cycle. Little or only light staining was seen in stromal cells and myometrium, and the pattern of staining did not differ between endometriotic and normal tissue. The presence of mRNA for aFGF and bFGF was demonstrated in normal endometrium. The detection of aFGF and bFGF mRNA in normal endometrium and aFGF- and bFGF-immunoreactivity in normal and endometriotic tissues suggests that these peptides may play a role in the proliferation and angiogenesis of normal and ectopic human endometrium.

Base Sequence↗
PubMed1993

Does mild zinc deficiency contribute to poor growth performance?

Zinc promotes growth in severely malnourished children, and mild zinc deficiency may limit growth in otherwise healthy children. An intervention study involving children aged six to seven years from a poor area of Guatemala failed to show beneficial effects of zinc on height and weight gain, although body fat status was increased. Further studies are needed to clarify the influence of mild zinc deficiency on growth.

Body Composition↗
PubMed1992

The expression of retinoic acid receptors in cultured human endometrial stromal cells and effects of retinoic acid.

Patterns of expression of retinoic acid receptors (RAR) in cultures of human endometrial stromal cells are described. Transcripts for all three classes of RAR were expressed in these cells but RAR-beta was expressed at a low level by comparison with RAR-alpha and RAR-gamma. The abundance of RAR-beta transcripts was elevated by treating the cells with retinoic acid, but there was no effect on the level of expression of RAR-alpha and RAR-gamma. The induction of RAR-beta by retinoic acid was detectable within 4 h and at low concentrations of retinoic acid (10(-10) M). Adenosine 3':5'-cyclic monophosphate (cAMP) analogues and forskolin, an adenylate cyclase activator, had no effect on the retinoic acid-mediated induction of RAR-beta, contrary to recent observations on embryonal carcinoma cells. However, the phosphodiesterase inhibitor, 3-isobutyl-1-methyl-xanthine (IBMX), forskolin and 8-bromo-cAMP depressed basal levels of RAR-beta expression. These data suggest that endometrial stromal cells may be a target tissue of retinoic acid in vivo, and imply a role for retinoic acid in the cyclical differentiation of human endometrium.

Blotting, Northern↗
PubMed1992

Ovarian steroid receptor expression in endometriosis and in two potential parent epithelia: endometrium and peritoneal mesothelium.

Endometriosis is an oestrogen dependent condition and it is expected that the tissue of origin of endometriosis will express receptors for the ovarian steroids. Two epithelia, endometrium and peritoneal mesothelium, are the potential parent epithelium. Oestrogen and progesterone receptor expression has been studied immunohistochemically in (i) timed endometrial biopsies from 25 normal subjects and 27 patients with endometriosis, (ii) 25 endometriotic biopsies and (iii) 42 peritoneal biopsies. Endometrium but not peritoneal mesothelium expresses both oestrogen and progesterone receptors. No difference in the intensity of staining between endometria of normal subjects compared with the endometria of patients with endometriosis was noted. In paired endometrial and endometriotic biopsies, the intensity of staining for the oestrogen receptor in stromal cells and for the progesterone receptor in both glandular and stromal cells was less in the endometriotic biopsies. These data provide circumstantial evidence for an endometrial origin for endometriosis although quantitative differences exist in receptor expression between endometrium and endometriosis.

Endometriosis↗
PubMed1992

Epidermal growth factor receptor expression in normal endometrium and endometriosis: an immunohistochemical study.

OBJECTIVE: To study epidermal growth factor (EGF) receptor expression in endometrium throughout the menstrual cycle and to compare EGF-receptor expression in endometrium from patients with endometriosis with receptor expression in synchronously sampled endometriosis and in endometrium from healthy women. DESIGN: An immunohistochemical study of receptor expression using murine monoclonal antibodies and timed endometrial and endometriotic biopsies. SUBJECTS: 25 healthy women and 27 patients with a diagnosis of endometriosis. RESULTS: Positive staining for EGF receptors was observed in 24 of 25 samples from normal women and in 26 of 27 endometrial samples from patients with endometriosis. In neither group was there any variation in the intensity of staining throughout the menstrual cycle and both glands and stroma were stained. EGF-receptor expression was observed in the glands of 15 out of 17 endometriotic lesions and in 12 of these biopsies positive staining was also present within endometriotic stroma. CONCLUSION: This study shows no difference in the intensity of staining of EGF receptors in endometrium throughout the menstrual cycle or between the glands of normal endometrium and those of endometriosis.

Endometriosis↗
PubMed1992

Starch digestion in young children with cystic fibrosis measured using a 13C breath test.

The study was designed to evaluate a non-invasive breath test using naturally 13C-rich corn (maize) as substrate to provide quantitative information about the digestion of starch by children in health and disease. The variability of background 13C:12C of young British children was investigated by collecting breath samples over 6 h from 17 healthy children, 6-35 mo old, and from seven children with cystic fibrosis, 25-48 mo old, in their homes. Background 13C enrichment was -26.6 and -25.4 delta per mil in the healthy and cystic fibrosis groups, respectively (p less than 0.01), and varied little during the day (SD = 0.4 delta per mil). Eight healthy children and five with cystic fibrosis were given a test breakfast of corn starch cooked in milk with sugar. The cystic fibrosis group repeated the test with the addition of an enzyme supplement containing alpha-amylase. Subjects accepted variable amounts of starch (range 0.2-2.8 g/kg body wt). The percentage of ingested 13C recovered during the 6 h after the meal increased with age in the healthy children (range 15-53%). Three children with cystic fibrosis had negligible 13C recoveries, and the other two had lower recoveries than expected for their age. The addition of enzymes did not consistently improve 13C recovery. We conclude that the 13C breath test based on corn has potential for investigating starch digestion in young children. Initial results suggest that starch digestion is impaired in some children with cystic fibrosis and that enzyme supplements do not improve digestion consistently or completely.

Breath Tests↗
PubMed1991

Bone mineral content of British and rural Gambian women aged 18-80+ years.

The bone mineral content (BMC) of the mid-shaft radius was measured in 446 rural Gambian and 349 British women aged 18-80+ years using single-photon absorptiometry. The two groups of women differed substantially in habitual calcium intake, calcium requirements for reproduction, physical activity and incidence of minimal-trauma fractures. The relationships of BMC with bone width (BW) and with body weight and height were explored using stepwise multiple regression analysis. The pattern of BMC with age was similar in The Gambia and Britain; BMC increased slightly to a peak at the end of the fourth decade followed by a decrease of about 30% between 40 and 70+ years. Gambian women had significantly lower BMC than British women of the same age (-5.6%, P less than 0.001) but after adjusting for weight, height and BW, the BMC of Gambian women was shown to be slightly higher than that of British women (+2.1%, P less than 0.05).

Absorptiometry, Photon↗
PubMed1991

Epidermal growth factor in human endometrium: proliferative effects in culture and immunocytochemical localization in normal and endometriotic tissues.

Endometrial proliferation is stimulated by oestradiol. The precise mechanism is poorly understood, but may be mediated by epidermal growth factor (EGF). The aim of the present study was to assess the effects of oestradiol and EGF on glandular and stromal proliferation in human endometrial cell cultures, and to determine the localization of EGF-like immunoreactivity (EGF-IR) using immunocytochemistry in normal and endometriotic tissue. Endometrium was obtained from women undergoing curettage or hysterectomy for benign disease, or laparoscopy for endometriosis. For tissue culture experiments, enriched glandular and stromal cells were prepared by digestion with collagenase and DNAase, and cultured for 4 days with oestradiol or EGF, both alone and in combination. Immunocytochemical studies were performed using sheep primary antibody against EGF, with binding visualized using the unlabelled antibody--enzyme method. In combination, oestradiol and EGF increased mean cell counts from 1.15 +/- 0.06 and 1.36 +/- 0.05 x 10(5)/ml to 1.68 +/- 0.1 (+46%) and 1.94 +/- 0.16 (+43%) x 10(5)/ml, in proliferative and secretory gland preparations respectively (n = 10, P less than 0.01). No effect was seen in stromal cell preparations; however the stimulation in gland preparations was further augmented after the addition of stromal-conditioned medium. EGF-IR was detected in endometrium from normal women, and in normal and ectopic endometrium from women with endometriosis. EGF-IR was seen in glands and stroma and was not related to the phase of the menstrual cycle. EGF may play a role in the oestrogen-stimulated proliferation of normal and endometriotic endometrium.

Animals↗
PubMed1991

Breast feeding and the older infant.

The possible benefits and disadvantages to the older infant of breast-feeding being continued after the introduction of solid foods are reviewed. The limited evidence from industrialised countries suggests that prolonged partial breast-feeding has little influence on child health and growth. In contrast, in poor areas of the developing world, the continuation of breast-feeding for 1-2 years after the introduction of other foods appears to have several major benefits. These include the supply of nutrients, the delivery of protective, digestive and trophic agents, and extending the period of infertility in the mother. Partial breast-feeding after 6 months is associated with reduced severity of infectious diseases particularly in severely malnourished individuals. There is no evidence that partial breast-feeding plays a causal role in poor growth performance. In poor areas of the developing world, breast-feeding, together with the provision of adequate amounts of other foods, should be encouraged for the first two years of life.

Breast Feeding↗
PubMed1991

Raised urinary secretory IgA in chronic diarrhoea.

Secretory IgA outputs in urine have been measured in 24 malnourished Gambian children who had been admitted to hospital with chronic diarrhoea and in 43 children from a rural Gambian village. Village children of poor nutritional state (less than or equal to 74% weight for age compared with the National Center for Health Statistics reference curve) had secretory IgA outputs that were only one third of those of better nourished individuals. In contrast, the patients with chronic diarrhoea had secretory IgA outputs that were significantly raised compared with village children, regardless of nutritional state. These results demonstrate that secretory IgA production in the urinary tract can be stimulated by intestinal disease, suggesting that malnourished children are able to mount a response to mucosal infection and supporting the hypothesis of a common secretory immune system.

Body Weight↗
PubMed1991

A semi-automated micromethod for the determination of calcium and phosphorus in human milk.

A simple, semi-automated method for the analysis of calcium and phosphorus in small volumes of human milk is described. Samples are ashed, digested with dilute hydrochloric acid and assayed with commercially available kits on a centrifugal analyser. The precision and accuracy of the method are similar to those of standard manual methods using larger volumes of milk. Analysis of human milk for phosphorus without prior ashing and digestion gives observed concentrations only 30-40% of their true value.

Autoanalysis↗
PubMed1991

Breast-milk calcium and phosphorus concentrations of mothers in rural Zaire.

The breast-milk calcium and phosphorus concentrations of 12 mothers living in a poor, rural area of Zaïre have been measured serially over 18 months of lactation. Calcium concentrations remained steady for the first 3-4 months and then decreased by approximately 27%. Phosphorus concentrations decreased by an average of 16% during the first 6 months and then reached a low plateau. The calcium:phosphorus ratio decreased from 1.7 in early lactation to 1.3 after 15 months. A wide range of mineral concentrations was observed between individuals in Zaïre and the differences between mothers were maintained throughout lactation. No influence of maternal nutritional status, age or parity on breast-milk mineral concentrations was observed. Comparison of the results of this study with published data from Britain and The Gambia obtained in the same laboratory demonstrated that breast-milk calcium concentrations in Zaïre resembled Gambian values in being significantly lower than those in Britain by 15%-20%. In contrast, breast-milk phosphorus concentrations in Zaïre were similar to those in Britain and were lower than those in The Gambia. This pattern of mineral composition resulted in Ca:P ratios in Zaïre that were intermediate in value between those of British and Gambian breast-milk. More information is required about the factors which determine calcium and phosphorus secretion into breast-milk.

Calcium↗
PubMed1991

Is human lactation a particularly efficient process?

The recommended dietary allowances of many expert committees (UK DHSS 1979, FAO/WHO/UNU 1985, USA NRC 1989) have set out the extra energy requirements necessary to support lactation on the basis of an efficiency of 80 per cent for human milk production. The metabolic efficiency of milk synthesis can be derived from the measurements of resting energy expenditure in lactating women and in a matched control group of non-pregnant non-lactating women. The results of the present study in Gambian women, as well as a review of human studies on energy expenditure during lactation performed in different countries, suggest an efficiency of human milk synthesis greater than the value currently used by expert committees. We propose that an average figure of 95 per cent would be more appropriate to calculate the energy cost of human lactation.

Adult↗
PubMed1990

Changes in plasma and whole blood lactate in response to arterial occlusion.

The development of lactic acidaemia in the adult forearm in response to partial and total arterial occlusion is described in both plasma and whole blood. Under conditions of total occlusion of the brachial artery lactate levels in the plasma compartment rise at a significantly faster rate; mean difference in gradients -11.6 95% confidence limits -15.6 and -7.6. Thus in these conditions they provide a more sensitive index of tissue hypoxia. Under conditions of partial occlusion there is no significant difference; mean difference in gradients 1.0 95% confidence limits 9.4 and -7.3. Though plasma lactate levels are more sensitive to the ischaemic state in certain circumstances, whole blood measurements are equally applicable to the monitoring of trends in blood lactic acid.

Acidosis, Lactic↗