Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 21
Filter
1.
Clin Obes ; 5(3): 127-35, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25873234

ABSTRACT

AIMS: Whether overweight is a risk factor for cardiovascular disease in the absence of metabolic disorders remains under debate and is largely unexamined in young women. We evaluated the risk of myocardial infarction and ischaemic stroke in fertile women conditional on time-dependent presence of metabolic disorders. MATERIALS AND METHODS: From nationwide registers we identified all normal weight (body mass index [BMI] ≥ 18.5 to <25 kg m(-2) and overweight (BMI ≥ 25 kg m(-2)) Danish women giving birth from 2004 to 2009. Using multivariable Poisson regression models adjusted for age, calendar year and smoking, the risk of the composite outcome of myocardial infarction and ischaemic stroke was assessed with metabolic disorders (i.e. hypertensive conditions, abnormal glucose metabolism and/or dyslipidaemia) included as time-dependent variables. RESULTS: The population comprised 261,489 women with median age of 30.5 years (interquartile range = [27.3, 33.8]). Median follow-up was 5.6 years (interquartile range = [4.0, 6.8]). Compared with normal weight women without metabolic disorders (with an incidence rate [IR] of 17.0 [95% confidence interval {CI} = 14.5-20.0] events per 100,000 person-years), overweight women without metabolic disorders had no significantly increased risk, IR 22.6 (CI = 18.3-27.8), adjusted incidence rate ratio (IRR), 1.26 (CI = 0.97-1.65). For women with metabolic disorders, IR was 30.2 (CI = 18.8-48.6) and adjusted IRR 1.77 (CI = 1.07-2.93) in normal weight, while IR was 87.1 (CI = 67.6-112.2) and IRR 4.24 (CI = 5 3.11-5.79) in overweight. CONCLUSIONS: The risk of myocardial infarction and ischaemic stroke was more strongly associated with the presence of metabolic disorders than with overweight per se in fertile women. Targeting prevention of metabolic disorders might be beneficial to reduce cardiovascular disease in overweight/obese young women.


Subject(s)
Brain Ischemia/etiology , Metabolic Diseases/complications , Myocardial Infarction/etiology , Overweight/complications , Stroke/etiology , Adult , Body Mass Index , Brain Ischemia/mortality , Female , Fertility , Humans , Metabolic Diseases/mortality , Myocardial Infarction/mortality , Obesity/complications , Obesity/mortality , Overweight/mortality , Registries , Retrospective Studies , Stroke/mortality
2.
Phys Rev Lett ; 111(22): 227001, 2013 Nov 27.
Article in English | MEDLINE | ID: mdl-24329465

ABSTRACT

We present a combined magnetic neutron scattering and muon spin rotation study of the nature of the magnetic and superconducting phases in electronically phase separated La(2-x)Sr(x)CuO(4+y), x=0.04, 0.065, 0.09. For all samples, we find long-range modulated magnetic order below T(N) is approximately equal to Tc=39 K. In sharp contrast to oxygen-stoichiometric La(2-x)Sr(x)CuO(4), we find that the magnetic propagation vector as well as the ordered magnetic moment is independent of Sr content and consistent with that of the "striped" cuprates. Our study provides direct proof that superoxygenation in La(2-x)Sr(x)CuO(4+y) allows the spin stripe ordered phase to emerge and phase separate from superconducting regions with the hallmarks of optimally doped oxygen-stoichiometric La(2-x)Sr(x)CuO(4).

3.
Dalton Trans ; 40(45): 12028-32, 2011 Dec 07.
Article in English | MEDLINE | ID: mdl-21858343

ABSTRACT

Reaction of the Single Molecule Magnet [Mn(12)O(12)(CH(3)CO(2))(16)(H(2)O)(4)] (Mn(12)) with mesogenic dendritic ligands Li (i = 4, 5) quantitatively yields functional clusters [Mn(12)O(12)(Li-H)(16)(H(2)O)(4)] (i = 4, 5) that self-organize into a thermotropic SmA-type liquid crystalline phase. The perturbation of the molecular interface by methylation of the terminal mesogenic cyanobiphenyl groups induces a significant decrease of the clearing temperature without affecting the magnetic properties and the supramolecular organization of the Mn(12)-based clusters.

4.
Prev Vet Med ; 101(1-2): 121-3, 2011 Aug 01.
Article in English | MEDLINE | ID: mdl-21195493

ABSTRACT

Danish pigs that are within optimal weight limits and have a high lean meat percentage (LMP) obtain the best prices at slaughter. Another reason to consider the variation in LMP is the assumed association between LMP and average daily weight gain (ADG) at the individual level. The aim of this study was to test whether high ADG was associated with low LMP and vice versa. A cohort of 99 pigs from a conventional Danish herd was followed from 30kg to slaughter. The data included days in the herd, start- and end-weights, calculated ADG and LMP, reported from the abattoir. The study also included existing data from 13,057 boars from a Danish boar test station. The results of the study demonstrated a significant negative association between LMP and ADG: Pearson's correlation coefficient (r)=-0.42 (95% CI: -0.57; -0.24) (p<0.0001) for the cohort and r=-0.42 (95% CI: -0.48; -0.36) (p<0.0001) for the boars.


Subject(s)
Meat , Swine , Weight Gain , Abattoirs , Animals , Cohort Studies , Denmark , Meat/economics , Thinness , Weight Gain/physiology
5.
Animal ; 4(11): 1922-8, 2010 Nov.
Article in English | MEDLINE | ID: mdl-22445153

ABSTRACT

Sows suffering from clinical signs of disease (e.g. lameness, wounds and shoulder ulcers) are often involuntarily culled, affecting the farmer's economy and the welfare of the animals. In order to investigate the interrelationships between clinical signs of individual pregnant group-housed sows, we performed an explanatory factor analysis to identify factors describing the patterns of variation of clinical signs. Moreover, we investigated how these emerging factors affected the probability of a sow to be either (i) euthanized, (ii) suddenly dead, (iii) sent to slaughter due to clinical signs of disease such as claw lesions or wounds or (iv) involuntarily culled (representing a pool of sows that were either euthanized, dead or sent to slaughter due to disease). Data from 2.989 pregnant sows in group-housing systems from 33 sow herds were included in the study. A thorough clinical examination was performed for each sow by using a protocol including 16 different clinical signs. Farmers recorded all cullings and deaths and the reasons for these actions in a 3-month period after the clinical examination. Among the observed sows, 4.2% were involuntarily culled during the 3-month period. From the explanatory factor analysis, we identified three factors describing the underlying structure of the 16 clinical variables. We interpreted the factors as 'pressure marks', 'wounds' and 'lameness' Logistic analyses were performed to investigate the effect of the three factors and the parity number of each sow on the four outcomes: (i) euthanized, (ii) suddenly dead, (iii) sent to slaughter due to clinical signs of disease and (iv) involuntarily culled. The analyses showed that 'lameness' significantly increased the risk of sows to be involuntarily culled (P = 0.016) or sent to slaughter due to clinical signs of disease (P = 0.026). Lameness is generally considered to be an important welfare problem in sows, which could explain the increased risk seen in this study. By contrast, 'pressure marks' and 'wounds' did not have any significant effect on the four outcomes (P > 0.05).

6.
J Bone Joint Surg Br ; 89(1): 121-6, 2007 Jan.
Article in English | MEDLINE | ID: mdl-17259430

ABSTRACT

Impacted bone allograft is often used in revision joint replacement. Hydroxyapatite granules have been suggested as a substitute or to enhance morcellised bone allograft. We hypothesised that adding osteogenic protein-1 to a composite of bone allograft and non-resorbable hydroxyapatite granules (ProOsteon) would improve the incorporation of bone and implant fixation. We also compared the response to using ProOsteon alone against bone allograft used in isolation. We implanted two non-weight-bearing hydroxyapatite-coated implants into each proximal humerus of six dogs, with each implant surrounded by a concentric 3 mm gap. These gaps were randomly allocated to four different procedures in each dog: 1) bone allograft used on its own; 2) ProOsteon used on its own; 3) allograft and ProOsteon used together; or 4) allograft and ProOsteon with the addition of osteogenic protein-1. After three weeks osteogenic protein-1 increased bone formation and the energy absorption of implants grafted with allograft and ProOsteon. A composite of allograft, ProOsteon and osteogenic protein-1 was comparable, but not superior to, allograft used on its own. ProOsteon alone cannot be recommended as a substitute for allograft around non-cemented implants, but should be used to extend the volume of the graft, preferably with the addition of a growth factor.


Subject(s)
Bone Morphogenetic Proteins/therapeutic use , Bone Substitutes/therapeutic use , Bone Transplantation/methods , Joint Prosthesis , Osseointegration/drug effects , Transforming Growth Factor beta/therapeutic use , Animals , Bone Morphogenetic Protein 7 , Coated Materials, Biocompatible , Dogs , Drug Evaluation, Preclinical , Durapatite , Osteogenesis/drug effects , Random Allocation
7.
Int Orthop ; 29(2): 67-72, 2005 Apr.
Article in English | MEDLINE | ID: mdl-15685457

ABSTRACT

We compared processed morselized bone allograft with fresh-frozen bone graft around noncemented titanium implants. Also, the influence of platelet-rich plasma (PRP) in combination with bone allograft was evaluated. Analysis was based on implant fixation and histomorphometry. PRP was prepared by isolating the buffy coat from autologous blood samples. Bone allograft was used fresh-frozen or processed by defatting, freeze drying, and irradiation. Cylindrical hydroxyapatite-coated titanium implants were inserted bilaterally in the femoral condyles of eight dogs. Each implant was surrounded by a 2.5-mm concentric gap, which was filled randomly according to the four treatment groups--group 1: fresh-frozen bone allograft; group 2: processed bone allograft; group 3: fresh-frozen bone allograft + PRP; group 4: processed bone allograft + PRP. Histological and mechanical evaluation demonstrated no influence of bone allograft processing. Even though the level of platelet in PRP was 7.7 times that found in whole blood, we found no improvement of bone formation or implant fixation by adding PRP.


Subject(s)
Blood Platelets/physiology , Bone Transplantation/physiology , Fracture Healing/drug effects , Joint Prosthesis , Plasma/physiology , Animals , Biocompatible Materials/therapeutic use , Bone Transplantation/methods , Dogs , Durapatite/therapeutic use , Osseointegration/drug effects , Osseointegration/physiology , Specimen Handling/methods , Titanium/therapeutic use
8.
J Orthop Res ; 22(3): 653-8, 2004 May.
Article in English | MEDLINE | ID: mdl-15099648

ABSTRACT

Platelet rich plasma (PRP) is an autologous source of growth factors. By application of PRP around cementless implants alone or in combination with bone allograft chips, early implant fixation and gap healing could be improved. We inserted two porous HA coated titanium implants extraarticularly in each proximal humerus of eight dogs. Each implant was surrounded by a 2.5 mm gap. Four treatments were block randomized to the four gaps in each dog: Treatment 1: empty gap, treatment 2: PRP, treatment 3: fresh frozen bone allograft, treatment 4: fresh frozen bone allograft+PRP. PRP was prepared from each dog prior to operation by isolating the buffycoat from centrifuged blood samples. Platelet count in PRP was increased 670% compared to baseline level. Calcium/thrombin was added to degranulate platelets and form a gel. Three weeks after surgery, push-out test and histomorphometri was performed. After three weeks, the non-allografted implants had poor mechanical properties. Bone grafting significantly increased implant fixation, bone formation in the gap and bone growth on the implant surface. We found no significant effect of PRP alone or mixed with bone allograft on implant fixation or bone formation. In conclusion, we showed the importance of bone allografting on early implant fixation and bone incorporation but we found no effect of PRP. More studies are needed to investigate the effect and possible clinical applications of platelet concentrates which are now being commercialised.


Subject(s)
Blood Platelets/physiology , Bone Transplantation , Implants, Experimental , Animals , Biomechanical Phenomena , Coated Materials, Biocompatible/pharmacology , Dogs , Hydroxyapatites/pharmacology , Osteogenesis , Transplantation, Homologous
10.
J Biomed Mater Res ; 55(1): 89-95, 2001 Apr.
Article in English | MEDLINE | ID: mdl-11426402

ABSTRACT

This study evaluated the effects of osteogenic protein 1/collagen composite (OP-1/col) mixed with impacted allograft around hydroxyapatite (HA)-coated titanium alloy implants in a canine model. The aim of the study was to test different doses of OP-1 growth factor in a collagen composite for stimulatory effect on allograft incorporation around an implant. Unloaded implants were inserted in each proximal humerus of 16 skeletally mature dogs. The cylindrical implants (4 x 9 mm) coated with HA were initially surrounded by a 3-mm gap into which allograft mixed with OP-1/col was impacted. Two different doses of OP-1 were investigated. In eight animals 325 mg OP-1 protein and 130 mg bovine collagen type I as carrier were mixed with the allograft chips. This composite is identical to the clinically used OP-1 device called Novus. In another eight animals a lower dose of 65 mg OP-1 protein and 130 mg bovine collagen type I was used. Control implants placed in the contralateral humerus were surrounded by allograft mixed with collagen carrier only. The dogs were euthanized at 6 weeks. Implant fixation was determined by push-out testing. Bone ingrowth and bone formation were evaluated by quantitative histomorphometry on serial sections of the bone-implant interface. Impacted allograft together with low-dose OP-1 enhanced bone volume in a zone adjacent to HA-coated titanium alloy implants. The high dose had no effect on bone formation. Mechanical fixation, bone ingrowth, and bone volume in the gap near the original trabecular bone were unaffected by both low and high OP-1/col composite. In this model and observation period, the low dose of OP-1/col composite mixed with impacted allograft has a moderate effect on bone healing around HA-coated implants and no effect on implant fixation.


Subject(s)
Bone Morphogenetic Proteins/pharmacology , Bone Transplantation/physiology , Coated Materials, Biocompatible , Collagen/pharmacology , Humerus/surgery , Hydroxyapatites , Prostheses and Implants , Titanium , Transforming Growth Factor beta , Transplantation, Homologous/physiology , Animals , Biocompatible Materials , Biomechanical Phenomena , Bone Morphogenetic Protein 7 , Cattle , Dogs , Materials Testing , Osteogenesis/drug effects , Stress, Mechanical
11.
Ugeskr Laeger ; 162(47): 6399-403, 2000 Nov 20.
Article in Danish | MEDLINE | ID: mdl-11116450

ABSTRACT

Growth factors with specific effects on bone cells have been known of for more than a decade. Clinical usage of growth factors has recently become possible due to recombinant gene technology. In vivo studies over the last five years have demonstrated that growth factors can stimulate bone formation and bone healing and these results have made growth factors candidates for future clinical use in orthopaedic surgery. Growth factors for clinical use will become commercially available in the near future. The aim of this review paper is to describe the most important growth factors with effect on bone tissue and to give an updated review on experimental and clinical data on growth factor mediated bone healing in situations related to orthopaedic surgery. Possible areas for future clinical usage of growth factors are also discussed.


Subject(s)
Bone Morphogenetic Proteins/administration & dosage , Growth Substances/administration & dosage , Wound Healing/drug effects , Bone Transplantation , Bone and Bones/drug effects , Bone and Bones/metabolism , Bone and Bones/pathology , Growth Substances/genetics , Humans , Prostheses and Implants , Spinal Fusion
12.
Am J Physiol Endocrinol Metab ; 279(6): E1413-25, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11093931

ABSTRACT

The concentration of pituitary adenylyl cyclase-activating polypeptide [PACAP-(1-38)] in porcine adrenal glands amounted to 14 +/- 3 pmol/g tissue. PACAP immunoreactive (PACAP-IR) fibers innervated adrenal chromaffin cells (often co-localized with choline acetyltransferase). Subcapsular fibers traversed the cortex-innervating endocrine cells and blood vessels [some co-storing mainly calcitonin gene-related peptide but also vasoactive intestinal polypeptide (VIP)]. PACAP-IR fibers were demonstrated in the splanchnic nerves, whereas IR adrenal nerve cell bodies were absent. In isolated, vascularly perfused adrenal gland, splanchnic nerve stimulation (16 Hz) and capsaicin (10(-5) M) increased PACAP-(1-38) release (1.6-fold and 6-fold respectively, P = 0.02). PACAP-(1-38) dose-dependently stimulated cortisol (2 x 10(-10) M; 24-fold increase, P = 0.02) and chromogranin A fragment (2 x 10(-9) M; 15-fold increase, P = 0.05) secretion. Both were strongly inhibited by the PAC(1)/VPAC(2) receptor antagonist PACAP-(6-38) (10(-7) M). PACAP-(6-38) also inhibited splanchnic nerve (10 Hz)-induced cortisol secretion but lacked any effect on splanchnic nerve-induced pancreastatin secretion. PACAP-(1-38) (2 x 10(-10) M) decreased vascular resistance from 5.5 +/- 0.6 to 4.6 +/- 0.4 mmHg. min. ml(-1). PACAP-(6-38) had no effect on this response. We conclude that PACAP-(1-38) may play a role in splanchnic nerve-induced adrenal secretion and in afferent reflex pathways.


Subject(s)
Adrenal Glands/chemistry , Adrenal Glands/innervation , Nerve Fibers/chemistry , Neuropeptides/analysis , Peptide Fragments/analysis , Animals , Capsaicin/pharmacology , Chromatography, High Pressure Liquid , Chromogranin A , Dose-Response Relationship, Drug , Epinephrine/metabolism , Gene Expression/physiology , Hydrocortisone/metabolism , Immunohistochemistry , In Situ Hybridization , Nerve Fibers/drug effects , Nerve Fibers/metabolism , Neuropeptides/genetics , Neuropeptides/metabolism , Neuropeptides/pharmacology , Norepinephrine/metabolism , Pancreatic Hormones/analysis , Pancreatic Hormones/metabolism , Peptide Fragments/genetics , Peptide Fragments/pharmacology , Pituitary Adenylate Cyclase-Activating Polypeptide , RNA, Messenger/analysis , Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide , Receptors, Pituitary Hormone/genetics , Splanchnic Nerves/chemistry , Splanchnic Nerves/cytology , Splanchnic Nerves/metabolism , Swine , Vascular Resistance/drug effects , Vascular Resistance/physiology , Vasoactive Intestinal Peptide/metabolism
13.
J Chromatogr A ; 873(2): 149-62, 2000 Mar 24.
Article in English | MEDLINE | ID: mdl-10757293

ABSTRACT

Simulated moving-bed (SMB) chromatography is attractive for reducing sorbent and solvent consumption relative to fixed-bed systems. In this contribution, we describe a novel and versatile method for further reducing solvent consumption in the case of reversed-phase chromatography. The method is based on the variation of the distribution coefficients of solutes to be separated upon varying the composition of a multi-component mobile phase. If the solvent strength of the desorbent is set higher than the solvent strength of the feed, the components will have smaller distribution coefficients in the extraction section of the SMB and hence will be more easily eluted. This will result in a lower desorbent flow and possibly also in a shorter desorbent zone, and, ultimately, in more concentrated products. The so-called "Triangle-method" by Storti et al. [AIChE J., 39 (1993) 471] to obtain the region of complete separation, is extended for this novel SMB method. Theoretical evaluation of the proposed methodology supports the anticipated solvent reduction relative to fixed-bed RP-HPLC for the cases of the purification of the polyketide antibiotic nystatin and the separation of bovine insulin from porcine insulin.


Subject(s)
Chromatography, Liquid/methods , Animals , Cattle , Insulin/isolation & purification , Solvents , Swine
14.
Acta Orthop Scand ; 71(6): 563-73, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11145382

ABSTRACT

This study addresses the clinical problems regarding access of wear debris to the bone-implant interface and the possible dissemination of polyethylene (PE) particles to distant organs. We inserted two implants into each knee of 7 dogs allowing access of joint fluid to the bone-implant interface with a 0.75 mm initial gap around the implant. Hydroxyapatite (HA)-coated and non-coated (Ti) titanium alloy implants were randomly allocated to each distal femoral condyle. PE particles were repeatedly injected into the right knee joint 3 weeks after surgery for a period of 49 weeks, while only vehicle was injected into the left knee joint. We found huge amounts of PE particles mainly in the bone-implant interface around Ti implants. Infiltration of mononuclear inflammatory cells was present around 3 of 7 Ti implants in relation to PE particles. HA implants had approximately 70% bone ongrowth. In contrast, no bone ongrowth was seen on any Ti implants, all being surrounded by a fibrous membrane. The number of PE particles was evaluated semi-quantitatively. More PE particles were found around Ti implants than with HA implants (p < 0.002). Specimens from iliac lymph nodes, liver, spleen and lung were examined and showed dissemination of PE particles only in regional lymph nodes.


Subject(s)
Biocompatible Materials/therapeutic use , Durapatite/therapeutic use , Knee Prosthesis , Osteolysis/prevention & control , Animals , Awards and Prizes , Dogs , Prosthesis Failure
15.
World J Surg ; 24(12): 1579-83, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11193727

ABSTRACT

Pancreastatin, a C-terminally amidated peptide derived from chromogranin A, is known to inhibit insulin secretion, pancreatic enzyme release, and gastric acid secretion. It also inhibits parathyroid hormone (PTH) secretion in animals. The physiologic and clinical relevance of pancreastatin in humans, however, is not known. Because pancreastatin has been found in parathyroid adenomas, we investigated the plasma levels in patients with primary hyperparathyroidism (pHPT). Thirteen patients operated on for solitary parathyroid adenoma were investigated. Plasma levels of pancreastatin and serum levels of ionized calcium and intact PTH were measured before and 6 weeks after operation. In 10 patients the levels were also monitored before and 60 minutes after adenoma excision. The adenomas were investigated for pancreastatin immunoreactivity by immunocytochemistry. The median weight of the excised parathyroid adenoma was 0.64 g (range 0.07-2.00 g). Cells displaying pancreastatin immunoreactivity were present in all adenomas examined and varied in number and immunostaining intensity among and within the adenomas. Intraoperatively, after adenoma excision the levels of PTH and pancreastatin declined (p < 0.01), whereas the levels of ionized calcium did not change (p = 0.96). At the 6-week follow-up the levels of ionized calcium and PTH had decreased compared to the preoperative levels (p < 0.01), and all patients were normocalcemic. In contrast, the pancreastatin levels were not changed (14.5 +/- 6.1 pmol/L preoperatively vs. 12.8 +/- 11.2 pmol/L 6 weeks postoperatively; p = 0.12). In patients with pHPT, pancreastatin is likely to be produced by the parathyroid adenoma. The changes in pancreastatin levels immediately after surgery warrant further investigation.


Subject(s)
Hyperparathyroidism/blood , Pancreatic Hormones/blood , Adenoma/blood , Adenoma/surgery , Adult , Aged , Aged, 80 and over , Chromogranin A , Female , Humans , Hyperparathyroidism/surgery , Immunohistochemistry , Male , Middle Aged , Parathyroid Neoplasms/blood , Parathyroid Neoplasms/surgery , Regression Analysis , Statistics, Nonparametric
16.
Clin Chem ; 45(4): 549-60, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10102916

ABSTRACT

BACKGROUND: Human chromogranin A (CgA) is an acidic protein widely expressed in neuroendocrine tissue and tumors. The extensive tissue- and tumor-specific cleavages of CgA at basic cleavage sites produce multiple peptides. METHODS: We have developed a library of RIAs specific for different epitopes, including the NH2 and COOH termini and three sequences adjacent to dibasic sites in the remaining part of CgA. RESULTS: The antisera raised against CgA(210-222) and CgA(340-348) required a free NH2 terminus for binding. All antisera displayed high titers, high indexes of heterogeneity ( approximately 1.0), and high binding affinities (Keff0 approximately 0.1 x 10(12) to 1.0 x 10(12) L/mol), implying that the RIAs were monospecific and sensitive. The concentration of CgA in different tissues varied with the assay used. Hence, in a carcinoid tumor the concentration varied from 0.5 to 34.0 nmol/g tissue depending on the specificity of the CgA assay. The lowest concentration in all tumors was measured with the assay specific for the NH2 terminus of CgA. This is consistent with the relatively low concentrations measured in plasma from carcinoid tumor patients by the N-terminal assay, whereas the assays using antisera raised against CgA(210-222) and CgA(340-348) measured increased concentrations. CONCLUSION: Only some CgA assays appear useful for diagnosis of neuroendocrine tumors, but the entire library is valuable for studies of the expression and processing of human CgA.


Subject(s)
Chromogranins/chemistry , Peptide Library , Adenoma/blood , Adenoma/chemistry , Adult , Antibody Specificity , Carcinoid Tumor/blood , Carcinoid Tumor/chemistry , Chromatography, Gel , Chromogranin A , Chromogranins/blood , Chromogranins/immunology , Digestive System/chemistry , Female , Humans , Immune Sera , Intestinal Neoplasms/blood , Intestinal Neoplasms/chemistry , Male , Middle Aged , Pheochromocytoma/blood , Pheochromocytoma/chemistry , Pituitary Neoplasms/blood , Pituitary Neoplasms/chemistry , Radioimmunoassay , Reference Values , Sensitivity and Specificity
17.
Pflugers Arch ; 436(3): 357-64, 1998 Aug.
Article in English | MEDLINE | ID: mdl-9644216

ABSTRACT

The purpose of this study was to examine how intracellular pH (pHi) regulation and histamine release are affected by HCO3- in rat peritoneal mast cells. The pHi was measured using the pH-sensitive dye 2', 7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF). We observed a pHi of 6.88+/-0.012 (n=24) in resting mast cells exposed to a HEPES buffer (pH 7.4), but a sustained drop of 0.21 pH units to 6.67+/-0.015 (n=23) when we exposed the mast cells to a HEPES/HCO3- buffer equilibrated at all time with 5% CO2 (pH 7.4). This fall in pHi is inhibited by the carbonic anhydrase inhibitor dichlorphenamide and is Na+-independent, indicating the involvement of Na+-independent Cl-/HCO3- exchange activity. Furthermore removal of external Cl- in the presence but not in the absence of HCO3- reversed the Cl-/HCO3- exchange and induced an alkaline load. The recovery from this alkaline load was dependent on external Cl- but independent of Na+. Both the alkalinization and the recovery were inhibited by the anion transport inhibitor 4, 4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS). In addition, 36Cl- uptake measurements confirm the presence of a Cl-/HCO3- exchanger. Histamine release stimulated by antigen and compound 48/80 was substantially reduced in the presence of HEPES/ HCO3- buffer (pHo 7.4, pHi 6.66). Histamine release was increased, however, when pHi was clamped to 6.66 in HCO3--free media (pHo 6.9). We conclude that: (1) Na+-independent Cl-/HCO3- exchange determines steady-state pHi in rat peritoneal mast cells; and (2) the reduction in histamine release observed in the presence of HCO3- is not due to its effect on pHi per se, but rather on other changes in ion transport.


Subject(s)
Bicarbonates/metabolism , Histamine/metabolism , Intracellular Fluid/metabolism , Mast Cells/metabolism , Peritoneal Cavity/cytology , 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid/pharmacology , Amiloride/analogs & derivatives , Amiloride/pharmacology , Animals , Antigens/immunology , Antiporters/metabolism , Biological Transport/drug effects , Buffers , Carbonic Anhydrase Inhibitors/pharmacology , Chloride-Bicarbonate Antiporters , Chlorides/metabolism , Dichlorphenamide/pharmacology , Hydrogen-Ion Concentration , In Vitro Techniques , Intracellular Fluid/drug effects , Male , Mast Cells/drug effects , Mast Cells/immunology , Rats , Rats, Sprague-Dawley , Sodium/metabolism , p-Methoxy-N-methylphenethylamine/pharmacology
18.
J Chromatogr B Biomed Appl ; 670(2): 199-207, 1995 Aug 18.
Article in English | MEDLINE | ID: mdl-8548010

ABSTRACT

Previous studies have measured histamine by derivatization with o-phthaldialdehyde (OPA) and mercaptoethanol (ME), followed by reversed-phase HPLC separation and electrochemical detection. The derivatization product, however, was very unstable. In the present study, inclusion of less polar solvents (e.g., acetonitrile or tetrahydrofuran) in the OPA/ME derivatization reaction produced an OPA/ME-histamine product that was stable for many hours. Changes of the HPLC mobile phase (increasing its ionic strength and pH and including triethylamine) dramatically improved the chromatography and reduced the histamine detection limit to < 0.1 pmol. The modified assay was suitable for batchwise manual derivatization of histamine samples followed by their automated analysis by HPLC with an automatic injector.


Subject(s)
Histamine/analysis , Animals , Chromatography, High Pressure Liquid , Electrochemistry , Hydrogen-Ion Concentration , Male , Mast Cells/chemistry , Mercaptoethanol , Rats , Rats, Sprague-Dawley , o-Phthalaldehyde
19.
Regul Pept ; 36(2): 283-97, 1991 Oct 29.
Article in English | MEDLINE | ID: mdl-1725220

ABSTRACT

Pancreastatin is a 49 amino acid peptide with a C-terminal glycine amide originally isolated from porcine pancreas. In the present study the cellular localisation of pancreastatin in porcine neuroendocrine tissue was examined immunocytochemically using an antiserum raised against porcine pancreastatin (33-49) that does not cross-react with porcine chromogranin A. In order to study the possible precursor-product relationship between chromogranin A and pancreastatin the cellular localisation of both peptides was examined in peripheral tissues using simultaneous double immunostaining. The pancreastatin antiserum immunostained cells and nerve fibers throughout the neuroendocrine system. In most of the examined tissues we found colocalisation of pancreastatin and chromogranin A immunostaining. These results support the precursor-product concept for chromogranin A and pancreastatin. However, in the gastrointestinal tract and the adenohypophysis a minor population of the endocrine cells exhibited immunostaining with only one of the two antibodies. This discrepancy between immunostaining with pancreastatin antiserum and monoclonal chromogranin A antibody could be due to absence of, or extensive, processing of chromogranin A in certain cell populations.


Subject(s)
Brain Chemistry , Chromogranins/isolation & purification , Digestive System/chemistry , Endocrine Glands/chemistry , Pancreatic Hormones/isolation & purification , Animals , Brain Chemistry/immunology , Chromogranin A , Chromogranins/immunology , Digestive System/immunology , Endocrine Glands/immunology , Fluorescent Antibody Technique , Organ Specificity , Pancreatic Hormones/immunology , Peptide Fragments/immunology , Protein Processing, Post-Translational , Staining and Labeling , Swine
20.
Percept Mot Skills ; 58(2): 651-62, 1984 Apr.
Article in English | MEDLINE | ID: mdl-6739258

ABSTRACT

The quality of student life in combined baccalaureate-M.D. degree programs has rarely been investigated although these programs address widely recognized problems in medical education. Through the use of an environmental stress inventory, 183 students' perceptions of the learning environment of a combined-degree program were examined. Students in that program rated few situations in their environment as stressful. Yet, they were significantly concerned about information overload and attendant time problems, just as their peers in 4-yr. schools were. Unlike their 4-yr. counterparts, however, they did not see relations with other students and faculty as problematic. Their scores on the inventory were best predicted at each year level by a combination of personal characteristics, notably living arrangements, sex, and to a lesser extent, introversion.


Subject(s)
Education, Medical , Stress, Psychological/psychology , Students, Medical/psychology , Adult , Environment , Female , Humans , Introversion, Psychological , Learning , Male , Sex Factors
SELECTION OF CITATIONS
SEARCH DETAIL
...