Biomedical subjects

S Harvey

Publications and source records attributed to S Harvey.

At least 19 recordsLinked to original sources

PubMed2006

Expression, translation, and localization of a novel, small growth hormone variant.

A novel transcript of the GH gene has been identified in ocular tissues of chick embryos. It is, however, unknown whether this transcript (small chicken GH, scGH) is translated. This possibility was therefore assessed. The expression of scGH mRNA was confirmed by RT-PCR, using primers that amplified a 426-bp cDNA of its coding sequence. This cDNA was inserted into an expression plasmid to transfect HEK 293 cells, and its translation was shown by specific scGH immunoreactivity in extracts of these cells. This immunoreactivity was directed against the unique N terminus of scGH and was associated with a protein of 16 kDa, comparable with its predicted size. Most of the immunoreactivity detected was, however, associated with a 31-kDa moiety, suggesting scGH is normally dimerized. Neither protein was, however, present in media of the transfected HEK cells, consistent with scGH's lack of a signal sequence. Similar moieties of 16 and 31 kDa were also found in proteins extracted from ocular tissues (neural retina, pigmented epithelium, lens, cornea, choroid) of embryos, although they were not consistently present in vitreous humor. Specific scGH immunoreactivity was also detected in these tissues by immunocytochemistry but not in axons in the optic fiber layer or the optic nerve head, which were immunoreactive for full-length GH. In summary, we have established that scGH expression and translation occurs in ocular tissues of chick embryos, in which its localization in the neural retina and the optic nerve head is distinct from that of the full-length protein.

Amino Acid Sequence↗

PubMed2006

Pulmonary artery catheters for adult patients in intensive care.

BACKGROUND: Pulmonary artery catheterization was adopted about 30 years ago and widely disseminated without rigorous evaluation as to whether it benefited critically ill patients. The technique is used to measure cardiac output and pressures in the pulmonary circulation to guide diagnosis and treatment. Clinicians believe these data can improve patients' outcomes, even in the absence of consensus about the specific interpretation of the data. OBJECTIVES: To assess the effect of pulmonary artery catheterization on mortality and cost of care in adult intensive care patients. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 2, 2006); MEDLINE (all records to April 2006); EMBASE (all records to April 2006); CINAHL (all records to April 2006) and reference lists of articles. We contacted manufacturers and researchers in the field. SELECTION CRITERIA: We included all randomized controlled trials in adults, comparing management with and without a pulmonary artery catheter (PAC). DATA COLLECTION AND ANALYSIS: We screened the titles and abstracts of the electronic search results and obtained the full text of studies of possible relevance for independent review. We determined the final results of the literature search by consensus between the authors. We did not contact study authors for additional information. MAIN RESULTS: We identified 12 studies. Mortality was reported as hospital, 28-day, 30-day, or intensive care unit. We considered studies of high-risk surgery patients (eight studies) and general intensive care patients (four studies) separately for the meta-analysis. The pooled odds ratio for the studies of general intensive care patients was 1.05 (95% confidence interval (CI) 0.87 to 1.26) and for the studies of high-risk surgery patients 0.99 (95% CI 0.73 to 1.24). Of the eight studies of high-risk surgery patients, five evaluated the effectiveness of pre-operative optimization but there was no difference in mortality when these studies were examined separately. Pulmonary artery catheterization did not affect intensive care unit (reported by 10 studies) or hospital (reported by nine studies) length of stay. Four studies, conducted in the United States, measured costs based on hospital charges billed to patients, which on average were higher in the PAC groups. AUTHORS' CONCLUSIONS: To date, there have been two multi-centre trials of the effectiveness of PACs for managing critically ill patients admitted to intensive care, although only one was adequately powered. Efficacy studies are needed to determine optimal management protocols and patient groups who could benefit from management with a PAC.

Adult↗

PubMed2006

Thiamine is synthesized by a salvage pathway in Rhizobium leguminosarum bv. viciae strain 3841.

In the absence of added thiamine, Rhizobium leguminosarum bv. viciae strain 3841 does not grow in liquid medium and forms only "pin" colonies on agar plates, which contrasts with the good growth of Sinorhizobium meliloti 1021, Mesorhizobium loti 303099, and Rhizobium etli CFN42. These last three organisms have thiCOGE genes, which are essential for de novo thiamine synthesis. While R. leguminosarum bv. viciae 3841 lacks thiCOGE, it does have thiMED. Mutation of thiM prevented formation of pin colonies on agar plates lacking added thiamine, suggesting thiamine intermediates are normally present. The putative functions of ThiM, ThiE, and ThiD are 4-methyl-5-(beta-hydroxyethyl) thiazole (THZ) kinase, thiamine phosphate pyrophosphorylase, and 4-amino-5-hydroxymethyl-2-methyl pyrimidine (HMP) kinase, respectively. This suggests that a salvage pathway operates in R. leguminosarum, and addition of HMP and THZ enabled growth at the same rate as that enabled by thiamine in strain 3841 but elicited no growth in the thiM mutant (RU2459). There is a putative thi box sequence immediately upstream of the thiM, and a gfp-mut3.1 fusion to it revealed the presence of a promoter that is strongly repressed by thiamine. Using fluorescent microscopy and quantitative reverse transcription-PCR, it was shown that thiM is expressed in the rhizosphere of vetch and pea plants, indicating limitation for thiamine. Pea plants infected by RU2459 were not impaired in nodulation or nitrogen fixation. However, colonization of the pea rhizosphere by the thiM mutant was impaired relative to that of the wild type. Overall, the results show that a thiamine salvage pathway operates to enable growth of Rhizobium leguminosarum in the rhizosphere, allowing its survival when thiamine is limiting.

Alkyl and Aryl Transferases↗

PubMed2006

An evaluation of the clinical and cost-effectiveness of pulmonary artery catheters in patient management in intensive care: a systematic review and a randomised controlled trial.

OBJECTIVES: To evaluate the clinical and cost-effectiveness of managing critically ill patients in adult, general intensive care with or without pulmonary artery catheters (PACs). DESIGN: An open, multi-centre, randomised controlled trial with economic evaluation (cost-utility and cost-effectiveness analysis). SETTING: The setting was general (mixed medical/surgical) intensive care units (ICUs) in the UK admitting adults. PARTICIPANTS: Adult patients in participating ICUs deemed by the responsible treating clinician to require management with a PAC. INTERVENTIONS: These were insertion of a PAC and subsequent clinical management, at the discretion of the responsible treating clinicians, using data derived from the PAC. The control group were managed without a PAC but with the option of using alternative cardiac output monitoring devices. MAIN OUTCOME MEASURES: The main outcome measure was hospital mortality. Secondary outcome measures were length of stay in the ICU, length of stay in an acute hospital and organ-days of support in the ICU. For the economic evaluation, the main outcome measure was quality-adjusted life-years (QALYs) and the secondary outcome measure was hospital mortality. RESULTS: Sixty-five ICUs in the UK participated. Of these, 43 (66%) used alternative cardiac output monitoring devices in control group patients. A total of 1263 patients were identified as being eligible for the trial. Of these, 1041 (82.4%) were randomised and allocated to management with (n = 519) or without (n = 522) a PAC. There were no losses to follow-up. However, 27 patients (13 in the PAC group and 14 in the control group) were withdrawn from the trial because either the patient withdrew consent on recovering mental competency or the relatives withdrew agreement following randomisation. Data on 1014 patients were included in the analysis. Participants in the two groups had similar baseline characteristics. There was no difference in hospital mortality for patients managed with (68.4%) or without (65.7%) a PAC. The adjusted hazard ratio (PAC versus no PAC) was 1.09 [95% confidence interval (CI) 0.94 to 1.27]. There was no difference in the median length of stay in ICU, the median length of stay in an acute hospital or mean organ-days of support in ICU between the two groups. The economic evaluation found that the expected cost per QALY gained from the withdrawal of PAC was 2985 pounds. The expected cost per life gained from the withdrawal of PAC was 22,038 pounds. CONCLUSIONS: Clinical management of critically ill patients with a PAC, as currently practised in the UK, neither improves hospital survival for adult, general intensive care patients nor reduces length of stay in hospital. The lack of demonstrable benefit from a device previously believed to be beneficial could be explained by statistical chance, by misinterpretation of PAC-derived data, by ineffective treatment strategies based on data correctly interpreted using the current paradigm or by subsequent inaction following insertion of the device. It is also possible that detailed data on haemodynamics, however used, cannot modify the disease process sufficiently to influence disease outcome. The economic evaluation, using decision analysis techniques rather than conventional hypothesis testing, suggests that the withdrawal of the PAC from routine clinical practice in the NHS would be considered cost-effective in the current decision-making climate, and might result in lives or life-years being saved at modest cost. With the declining use of PACs in the UK and the findings of this report indicating no overall benefit from management with a PAC, it should now be possible to examine protocolised management with a PAC in selected groups of critically ill patients against appropriate controls, something that was difficult while PACs were the considered standard of care.

Adolescent↗

PubMed2005

Heterogeneity of growth hormone immunoreactivity in lymphoid tissues and changes during ontogeny in domestic fowl.

Growth hormone (GH) expression is not confined to the pituitary and occurs in many extrapituitary tissues. Here, we describe the presence of GH-like moieties in chicken lymphoid tissues and particularly in the bursa of Fabricius. GH-immunoreactivity (GH-IR), determined by ELISA, was found in thymus, spleen, and in bursa of young chickens, but at concentrations <1% of those in the pituitary gland. Although the GH concentration in the spleen and bursa was approximately 0.82 and 0.23% of that in the pituitary at 9-weeks of age, because of their greater mass, the total GH content in the spleen, bursa, and in thymus were 236, 5.18, and 31.5%, respectively, of that in the pituitary gland. This GH-IR was associated with several proteins of different molecular size, as in the pituitary gland, when analyzed by SDS-PAGE under reducing conditions. While most of the GH-IR in the pituitary was associated with the 26 kDa monomer (40%), the putatively glycosylated 29 kDa variant (16%), the 52 kDa dimer (14%) and the 15 kDa submonomeric isoform (16%), GH-IR in the lymphoid tissues was primarily associated (27-36%) with a 17 kDa moiety, although bands of 14, 26, 29, 32, 37, 40, and 52 kDa were also identified in these tissues. The heterogeneity pattern and relative abundance of bursal GH-IR bands were determined during development between embryonic day 13 (ED13) and 9-weeks of age. The relative proportion of the 17 kDa GH-like band was higher (45-58%) in posthatched birds than in the 15 and 18-day old embryos (21 and 19%, respectively). The 26 kDa isoform was minimally present in embryos (<4% of total GH-IR) but in posthatched chicks it increased to 12-20%. Conversely, while GH-IR of 37, 40, and 45 kDa were abundantly present in embryonic bursa ( approximately 30% at ED13 and approximately 52-55% at ED15 and ED18, respectively), in neonatal chicks and juveniles they accounted for less than 5%. These ontogenic changes were comparable to those previously reported for similar GH-IR proteins in the chicken testis during development. In summary, these results demonstrate age-related and tissue-specific changes in the content and composition of GH in immune tissues of the chicken, in which GH is likely to be an autocrine or paracrine regulator.

Animals↗

PubMed2004

Growth hormone in the male reproductive tract of the chicken: heterogeneity and changes during ontogeny and maturation.

Growth hormone (GH) gene expression is not confined to pituitary somatotrophs and occurs in many extrapituitary tissues. In this study, we describe the presence of GH moieties in the chicken testis. GH-immunoreactivity (GH-IR), determined by ELISA, was found in the testis of immature and mature chickens, but at concentrations <1% of those in the pituitary gland. The immunoassayable GH concentration in the testis was unchanged between 4 and 66 weeks of age, and approximately 10-fold higher than that at 1-week of age and 25-fold higher than that in 1-day-old chicks and perinatal (embryonic day 18) embryos. This immunoreactivity was associated with several proteins of different molecular size, as in the pituitary gland, when analyzed by SDS-PAGE under reducing conditions. However, while most of the GH-IR in the pituitary ( approximately 40 and 15%, respectively) is associated with monomer (26 kDa) or dimer (52 kDa) GH moieties GH-IR in the testis is primarily (30-50%) associated with a 17 kDa moiety. GH bands between 32 and 45 kDa are also relatively more abundant in the testis than in the pituitary. During ontogeny the relative abundance of a 14 kDa GH and 40 kDa GH moieties in the testis significantly declined, whereas the relative abundance of the 17 and 45 kDa moieties increased with advancing age. In adult birds, GH-IR was widespread and intense in the seminiferous tubules. Although the GH-IR was not present in the basal compartment of Sertoli cells, nor in spermatogonia and primary spermatocytes, it was abundantly present in secondary spermatocytes and spermatids in the luminal compartments of the tubules as well as in some surrounding myocytes and interstitial cells. In summary, immunoreactive GH moieties are present in the chicken testis but at concentrations far less than in the pituitary. Age-related changes in the relative abundance of testicular GH variants may be related to local (autocrine/paracrine) actions of testicular GH. The localization of GH in spermatocytes and spermatids suggests hitherto unsuspected roles in gamete development.

Aging↗

PubMed2004

Testicular growth hormone (GH): GH expression in spermatogonia and primary spermatocytes.

Growth hormone (GH) gene expression is not restricted to pituitary somatotrophs and has recently been demonstrated in a variety of extrapituitary sites in mammals and the domestic chicken. The possibility that GH gene expression occurs in the male reproductive system of chickens was therefore examined, since GH has established roles in male reproductive function and GH immunoreactivity is present in the chicken testis. Using RT-PCR and oligonucleotide primers for pituitary GH cDNA, GH mRNA was shown to be present in the testes and vas deferens of adult cockerels. Although testicular GH mRNA was of low abundance (not detectable by Northern blotting), a 690 bp fragment of the amplified testicular GH cDNA was cloned and had a nucleotide sequence 99.6% homologous with pituitary GH cDNA. GH mRNA was localized by in situ hybridization in spermatogonia and primary spermatocytes of the seminiferous tubules, but unlike testicular GH-immunoreactivity, GH mRNA was not present in secondary spermatocytes, spermatids or spermatozoa. The presence of Pit-1 mRNA in the male reproductive tract may indicate Pit-1 involvement in GH expression in these tissues. The presence of GH receptor mRNA in the testis and vas deferens also suggests they are target sites for GH action. These results demonstrate, for the first time, expression of the pituitary GH gene in the testis, in which GH mRNA was discretely localized in primary spermatocytes. The local expression of the GH gene in these cells suggests autocrine or paracrine actions of GH during spermatogenesis.

Amino Acid Sequence↗

PubMed2003

Accident and emergency departments are still failing to assess asthma severity.

OBJECTIVES: To quantify the documentation of vital signs in children attending accident and emergency (A&E) for asthma and to assess whether indicators of severity were used appropriately. METHODS: Records of all children aged 3 to 14 attending A&E for the treatment of asthma in four London hospitals over a three month period were examined for documentation of heart rate, respiratory rate, peak expiratory flow rate, oxygen saturation, and fraction of inspired oxygen. The relation between severity indicators and whether the child was admitted or not was examined. RESULTS: There were 255 attendances in 229 children. Heart rate, respiratory rate, and oxygen saturation were recorded on most attendances (94.5%, 85.5%, and 96.8%) but fraction of inspired oxygen and peak flow were recorded in few children (48.6% and 48.5%). Heart rate and respiratory rate were higher and oxygen saturation lower in children who were admitted compared with those who were not. CONCLUSIONS: Assessment of airways obstruction is inadequate in children but when measured may be used appropriately to guide admission. There is a need for interventions to improve assessment of children attending A&E for asthma.

Adolescent↗

PubMed2003

Growth hormone in the nervous system: autocrine or paracrine roles in retinal function?

Growth hormone (GH) is primarily produced in the pituitary gland, although GH gene expression also occurs in the central and autonomic nervous systems. GH-immunoreactive proteins are abundant in the brain, spinal cord, and peripheral nerves. The appearance of GH in these tissues occurs prior to the ontogenic differentiation of the pituitary gland and prior to the presence of GH in systemic circulation. Neural GH is also present in neonates, juveniles, and adults and is independent of changes in pituitary GH secretion. Neural GH is therefore likely to have local roles in neural development or neural function, especially as GH receptors (GHRs) are widespread in the nervous system. In recent studies, GH mRNA and GH immunoreactive proteins have been identified in the neural retina of embryonic chicks. GH immunoreactivity is present in the optic cup of chick embryos at embryonic day (ED) 3 of the 21-d incubation period. It is widespread in the neural retina by ED 7 but also present in the nonpigmented retina, choroid, sclera, and cornea. This immunoreactivity is associated with proteins in the neural retina comparable in size with those in the adult pituitary gland, although it is primarily associated with 15-16 kDa moieties rather than with the full-length molecule of approximately 22 kDa. These small GH moieties may reflect proteolytic fragments of "monomer" GH and (or) the presence of different GH gene transcripts, since full-length and truncated GH cDNAs are present in retinal tissue extracts. The GH immunoreactivity in the retina persists throughout embryonic development but is not present in juvenile birds (after 6 weeks of age). This immunoreactivity is also associated with the presence of GH receptor (GHR) immunoreactivity and GHR mRNA in ocular tissues of chick embryos. The retina is thus an extrapituitary site of GH gene expression during early development and is probably an autocrine or paracrine site of GH action. The marked ontogenic pattern of GH immunoreactivity in the retina suggests hitherto unsuspected roles for GH in neurogenesis or ocular development.

Animals↗

PubMed2003

Extrapituitary GH in the chicken: underestimation of immunohistochemical staining by Carnoy's fixation.

GH has previously been shown to be present in peripheral extrapituitary tIssues of chick embryos, but the cellular distribution of GH immunoreactivity is still uncertain because of differing immunohistochemical findings. The possibility that this uncertainty reflects differences in fixation of the embryonic tIssues was assessed by comparing GH immunoreactivity in tIssues fixed in 4% (w/v) paraformaldehyde or Carnoy's fluid (60% ethanol (v/v); 30% chloroform (v/v); 10% acetic acid (v/v)). A widespread distribution of GH immunoreactivity was seen in paraformaldehyde-fixed tIssues, although it was particularly intense in the spinal cord, dorsal and ventral root ganglia, notochord, myotome, epidermis, crop, heart, lung and humerus. In marked contrast, GH immunoreactivity in embryonic tIssues fixed with Carnoy's was more discrete and mainly restricted to marginal and mantle layers of the spinal cord, spinal nerves, the ventral root ganglia and the extensor nerve of the anterior limb bud. Since these are neural derivatives, Carnoy's fixation appears to preferentially result in neural GH staining, whereas GH staining in neural and non-neural tIssues is seen after paraformaldehyde fixation. Carnoy's, because it is a precipitive fixative, may only fix large GH moieties, whereas GH in peripheral tIssues includes numerous molecular variants, many of which are of relatively small size. Paraformaldehyde, because it is a cross-linking fixative, preferentially fixes peptides and small proteins, and it may therefore fix more GH moieties than Carnoy's fluid. Carnoy's fixation appears to underestimate GH immunoreactivity in immunohistochemical studies on the cellular distribution of GH-like proteins in embryonic chicks.

Animals↗

PubMed2003

Ghrelin-induced GH secretion in domestic fowl in vivo and in vitro.

Although avian and mammalian species differ significantly in their regulation of GH secretion, preliminary studies have demonstrated in vivo GH responses to ghrelin in chickens, as in mammals. However, the relative potency of ghrelin as a GH-releasing hormone (GHRH) in birds is uncertain, as is its site of action. The intravenous administration of human ghrelin to immature chickens promptly increased the circulating GH concentration (within 10 min), although this was transitory and was only maintained for 20 min. This GH response was dose-related with an EC50 of approximately 3.0 microg/kg, comparable with the reported potency of human GHRH in chickens. When incubated with dispersed pituitary cells, human ghrelin induced dose-dependent GH release over a range of 10(-6) to 10(-9) M, with an EC50 of 7.0 x 10(-8) M, comparable with that induced by human GHRH (EC50 6.0 x 10(-8) M), although it was less effective at doses of 10(-6) to 10(-8) M. This was due to direct effects on pituitary somatotrophs, since human ghrelin increased GH release (determined by the reverse hemolytic plaque assay) from individual pituitary cells. The incubation of these cells with human ghrelin induced a dose-dependent increase in the numbers of somatotrophs secreting GH and in the amount of GH released by each cell. In summary, these results demonstrated that ghrelin is a dose-related GH-releasing factor in chickens with a potency comparable with that induced by human GHRH. The GH-releasing action of ghrelin is due, at least in part, to stimulatory actions on the numbers of somatotrophs induced to release GH and upon the amount of GH released from individual somatotrophs.

Animals↗

PubMed2003

Growth hormone therapy and Quality of Life: possibilities, pitfalls and mechanisms.

The actions of growth hormone (GH) are not restricted to growth: GH modulates metabolic pathways as well as neural, reproductive, immune, cardiovascular, and pulmonary physiology. The importance of GH in most physiological systems suggests that GH deficiency at any age would be associated with significant morbidity. However, prior to the advent of recombinant GH, cadaver-derived GH was only used therapeutically to correct the height deficit, and thereby hypothetically improve quality of life (QoL), in GH-deficient children. Physicians now have access to unlimited, albeit expensive, supplies of recombinant GH, and are considering the advisability of GH replacement or supplementation in other patient populations. This paper analyses studies investigating the relationship between GH and QoL in GH-deficient children or adults, in GH-replete short children suffering from idiopathic short stature, Turner syndrome, or intrauterine growth retardation and in GH-deficient or replete elderly adults. Possible mechanisms by which GH might improve QoL at neural and somatic sites are also proposed.

Adult↗

PubMed2002

A prospective study of the short-term outcomes of hysterectomy with and without oophorectomy.

OBJECTIVE: To determine the symptom profile and satisfaction rate for women undergoing hysterectomy with and without oophorectomy STUDY DESIGN: Women under 46 years of age who underwent hysterectomy with (n = 266) and without oophorectomy (n = 57) were followed for six months. RESULTS: Satisfaction was high at six months. In-hospital complication rates were 28% in Group 1 and 39% in Group 2 (p = 0.11). Pelvic pain was reported in more than half the women at six weeks. A reduction in constipation, diarrhoea, abdominal and pelvic pain, and depression was reported at six months. Quality of sexual function in women did not improve. New symptoms of pelvic pain or depression were present at six months in more than 16% to 37% of the women. Regrets about loss of fertility were increased at six months. CONCLUSIONS: Although levels of satisfaction with the procedure of hysterectomy were high, new symptoms and regrets about the loss of fertility were commonly reported.

Adaptation, Physiological↗

PubMed2002

GH as a co-gonadotropin: the relevance of correlative changes in GH secretion and reproductive state.

It is now well established that exogenous GH promotes sexual maturation and reproductive function. The possibility that this may reflect physiological actions of endogenous GH has, however, rarely been considered. Correlative changes in GH secretion and reproductive state (puberty, pregnancy, lactation, menopause and ovarian cycles) are thus the primary focus of this review. GH secretion is, for instance, elevated during major transitions in reproductive status such as puberty and pregnancy. In some cases, augmented circulating GH levels are paired with hepatic GH resistance. This interaction may permit selective activation of gonadal responses to GH without activating IGF-I-mediated systemic responses. This selective activation may also be mediated by autocrine, paracrine or intracrine GH actions, since GH is also synthesized in reproductive tissues. Correlative changes in GH secretion and reproductive state may be mediated by events at the hypothalamic, pituitary and gonadal level. In addition to direct effects on gonadal function, GH may influence reproductive activity by increasing gonadotropin secretion at the hypothalamic and pituitary level and by enhancing gonadotropin responsiveness at the gonadal level. The close association between reproductive status and the somatotrophic axis supports the physiological importance of GH in reproductive function.

Adolescent↗

PubMed2002

Ghrelin: a hypothalamic GH-releasing factor in domestic fowl (Gallus domesticus).

Ghrelin, a recently discovered peptide in the mammalian hypothalamus and gastrointestinal tract is thought to be the endogenous ligand for the GH secretagogue (GHS) receptor and it stimulates GH release in rats and humans. The possibility that ghrelin is present in birds was therefore assessed, since a GHS receptor is present in the chicken pituitary gland. Although immunoreactive ghrelin is readily detectable in the rat stomach and ileum, ghrelin immunoreactivity could not be detected in the chicken proventriculus, stomach, ileum or colon, whereas somatostatin immunoreactivity, in contrast and as expected, was readily detectable in the chicken gastrointestinal tract. Ghrelin immunoreactivity was, however, present in the chicken hypothalamus, although not in the arcuate (infundibular) nucleus, as in rats. Discrete parvocellular cells and neuronal fibers with ghrelin immunoreactivity were present in the anterior medial hypothalamus. This immunoreactivity was specific and completely abolished following the preabsorption of the antibody with an excess of human ghrelin. Ghrelin immunoreactivity was also present in clusters of large ovoid magnocellular cells in the nucleus magnocellularis preopticus pars medialis, nucleus magnocellularis preopticus supraopticus and in the chiasmaopticus. Immunoreactivity for ghrelin was restricted to the cytoplasm of the perikarya and their axonal sprouts. Immunoreactivity for ghrelin was not seen in any other hypothalamic nuclei. In a preliminary experiment, circulating GH concentrations in conscious immature chicks were promptly increased following bolus i.v. administration of human ghrelin. The increase in GH concentration (approximately three times that in the controls) was comparable with that induced by the same dose (10 microg/kg) of human GH-releasing hormone, although less than that (approximately sixfold) induced by thyrotropin-releasing hormone. These results demonstrate the presence of a ghrelin-like protein in the chicken hypothalamus and suggest that it participates in the regulation of GH secretion in birds.

Animals↗

PubMed2001

Extrapituitary beta TSH and GH in early chick embryos.

Somatotropes and thyrotropes are thought to be derived from the same cellular lineage and the expression of both growth hormone (GH) and thyrotropin (beta TSH) is thought to be dependent upon the same (Pit-1) transcription factor. The presence and comparative distribution of GH- and beta TSH-immunoreactivity in early chick embryos, was therefore investigated, especially as extrapituitary GH-immunoreactive cells are present in some peripheral tissues of early chick embryos prior to the ontogenic differentiation of the pituitary gland. At the end of the first trimester of incubation (embryonic day (ED) 7), GH-immunoreactivity was widespread in the head, particularly in neural tissue. Strong labeling was found in the diencephalon and mesencephalon and in neural ganglia and the trigeminal nerve. beta TSH-immunoreactivity was also present in these tissues, although restricted to the ependymal cells lining the diocoele and mesocoele and absent from mantle layers. It was also present in the cellular layer lining the otic vesicle, which was devoid of GH staining. In contrast, Rathke's pouch, the primordial pituitary gland was without GH- or beta TSH-staining. Control sections incubated with preabsorbed antisera or with pre-immune serum were completely devoid of staining. In the trunk, the epidermal cells were stained for beta TSH, but not for GH. Intense GH-immunoreactivity was present in the ventral and dorsal horns of the spinal cord and was particularly strong in the outer marginal layer. In contrast, beta TSH-immunoreactivity was again restricted to ependymal cells lining the spinal canal, which were devoid of GH-immunoreactivity. Strong GH staining was also present in the dorsal and ventral root ganglia, both of which lacked significant beta TSH staining. In non-neural tissues, both GH and beta TSH staining was present in the crop, although in topographically different cells. beta TSH-immunoreactivity was also present in the cells lining the bronchial ducts and the adluminal linings of the pleural and pericardial cavities. GH-immunoreactivity, in contrast, was absent from the lung but present in the surrounding intracostal muscles and in the Müllerian duct. Both GH- and beta TSH-immunoreactivity was present in liver hepatocytes. These results clearly show, for the first time, the presence of TSH-immunoreactivity in central and peripheral tissues of the ED7 chick embryo, prior to the differentiation of pituitary thyrotropes. They also show that beta TSH- and GH-immunoreactive cells are differentially located within embryonic tissues.

Animals↗

PubMed2001

Identification of gene expression profiles that predict the aggressive behavior of breast cancer cells.

With the goal of identifying genes that have an expression pattern that can facilitate the diagnosis of primary breast cancers (BCs) as well as the discovery of novel drug leads for BC treatment, we used cDNA hybridization arrays to analyze the gene expression profiles (GEPs) of nine weakly invasive and four highly invasive BC cell lines. Differences in gene expression between weakly and highly invasive BC cells were identified that enabled the definition of consensus GEPs for each invasive phenotype. To determine whether the consensus GEPs, comprising 24 genes, could be used to predict the aggressiveness of previously uncharacterized cells, gene expression levels and comparative invasive and migratory characteristics of nine additional human mammary epithelial cell strains/lines were determined. The results demonstrated that the GEP of a cell line is predictive of its invasive and migratory behavior, as manifest by the morphology of its colonies when cultured on a matrix of basement membrane constituents (i.e., Matrigel). We found that the expression of keratin 19 was consistently elevated in the less aggressive BC cell lines and that vimentin and fos-related antigen-1 (FRA-1) were consistently overexpressed in the more highly aggressive BC cells. Moreover, even without these three genes, the GEP of a cell line still accurately predicted the aggressiveness of the BC cell, indicating that the expression pattern of multiple genes may be used as BC prognosticators because single markers often fail to be predictive in clinical specimens.

Animals↗

PubMed2001

Insights into a plasma membrane signature.

The plasma membrane (PM) is an organized biological system that serves as a structural barrier and communication interface with the extracellular environment. Many basic questions regarding the PM as a system remain unanswered. In particular, we do not understand the scope of similarity and differences in protein expression at the PM. This study takes an initial step toward addressing these questions by comparing the PM proteomes of fibroblasts and mammary carcinoma cells. Three sets of proteins were revealed by the study. The first set comprises between 9 and 23% of all proteins at the PM and appears to be common to both fibroblasts and mammary carcinoma. A second group of proteins, comprising approximately 40% of the proteins at the PM, is tightly linked to cell lineage. The third set of proteins is unique to each cell line and is independent of cell lineage. It is reasonable to hypothesize then, that this third group of proteins is responsible for unique aspects of cell behavior. In an effort to find proteins linked to the metastatic phenotype, we identified several proteins that are uniquely expressed at the PM of the metastatic MDA-MB-435 cells. These proteins have functions ranging from cell adhesion to the regulation of translation and the control of oxidant stress.

Breast Neoplasms↗