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At least 847 records · Page 47Linked to original sources
PubMed1998

Vascular remodeling and altered protein expression during growth of coronary collateral arteries.

The cellular mechanism of growth of coronary collateral vessels (adaptive arteriogenesis) is still poorly understood. To define a possible role of an altered expression pattern of cellular and matrix proteins in this process we implanted a constricting device around the left circumflex artery in 25 canine hearts and sacrificed the animals at the time of initiation (3 weeks), high activity (6 weeks) and discontinuation (8 weeks) of vessel growth. Methods were electron microscopy, labeling with Ki-67, the TUNEL method and immunofluorescence with confocal laser microscopy. As described earlier, the collateral vessels increased in wall thickness by the formation of a neointima without luminal narrowing. We report here for the first time that extensive vascular remodeling including migration, proliferation and apoptosis in all cell types takes place during the growth phase but not in more mature vessels. The most obvious difference with normal vessels is the reiteration of an embryonal expression pattern in smooth muscle cells of the neointima which includes a significant reduction of desmin and alpha-smooth muscle actin, calponin and vinculin. Fibronectin as a promoter of migration and adhesion was abundant, its antagonist tenascin and chondroitin sulfate showed patchy localization. A completely new finding in arteriogenesis is the involvement of mast cells releasing histamine and serotonin and probably cytokines. Vascular protein expression returned to almost normal at 8 weeks indicating cessation of remodeling. We conclude that in collateral vessel development an altered cellular and matrix protein expression is involved in a drastic case of positive vascular remodeling finally resulting in mature vessels 20-fold increased in size which are capable of maintaining the functional and structural integrity of the myocardium at risk.

Actins↗
PubMed2006

Calponin and caldesmon cellular domains in reacting microvessels following traumatic brain injury.

Calponin (Cp) and caldesmon (Cd) are actin-binding proteins involved in the regulation of smooth muscle (SM) tone during blood vessel contraction. While in vitro studies have reported modifications of these proteins during vessel contractility, their role in vivo remains unclear. Traumatic brain injury (TBI) causes disruption of cerebral microvascular tone, leading to sustained contractility in reacting microvessels and cerebral hypoperfusion. This study aimed to determine the spatial and temporal expressions of Cp and Cd in rat cerebral cortical and hippocampal microvessels post-TBI. Reacting microvessels were analyzed in control, 4, 24, and 48 h post-injury. Single and double immunocytochemical techniques together with semiquantitative analyses revealed a Cp upregulation in SM at all time frames post-TBI; with the protein migrating from SM cytosol to the vicinity of the cell membrane. Similarly, Cd immunoreactivity significantly increased in both SM and endothelial cells (En). However, while Cp and Cd in SM remained elevated, their levels in En returned to normal at 48 h post-TBI. The results suggest that Cp and Cd levels increase while compartmentalizing to specific subcellular domains. These changes are temporally associated with modifications in the cytoskeleton and contractile apparatus of SM and En during blood vessel contractility. Furthermore, these changes may underlie the state of sustained contractility and hypoperfusion observed in reacting microvessels after TBI.

Animals↗
PubMed1999

Evolution of acute cytomegalovirus gastritis to chronic gastrointestinal dysmotility in a nonimmunocompromised adult.

A 30-year-old nonimmunocompromised woman developed chronic gastrointestinal dysmotility as a consequence of acute cytomegalovirus infection. The acute nature of the infection was documented by high immunoglobulin M antibody titer to cytomegalovirus (CMV); the chronicity of the infection was shown by persistence of CMV in biopsy specimens of her gastrointestinal tract over a 21/2-year period. Gastrointestinal dysmotility was confirmed by delayed emptying on gastric nuclear scintigraphy, by retrograde propagation of migrating myoelectric complexes on small intestinal manometry, and by presence of tachygastria on cutaneous electrogastrography. The patient's nausea, vomiting, abdominal pain, and early satiety resolved after a short course of treatment with leuprolide acetate but returned after medication was discontinued. Her symptoms persisted despite clearance of CMV from the gastrointestinal tract after a course of treatment with ganciclovir. These observations show that acute CMV infection can cause gastrointestinal dysmotility in nonimmunocompromised individuals and that the disturbance in gastrointestinal motor function may persist for years after viral infection of the gastrointestinal tract has been eradicated.

Acute Disease↗
PubMed2004

A reproducible laser-wounded skin equivalent model to study the effects of aging in vitro.

Skin aging involves both chronological and photoaging processes. The effects of these processes are often overlapping and include changes in both the stratified epithelium and the fibroblast-rich dermis. Wound healing is frequently delayed with aging and can result in scarring. A skin equivalent model can be used to study the role of cells and the extracellular matrix in the process of wound healing. Current studies using this model employ a full-thickness wound placed atop a nonwounded dermis to mimic a partial-thickness wound. However, a true reproducible partial-thickness wound model has yet to be described. In this study, we investigated whether a laser-wounded skin equivalent would be a useful partial-thickness wound healing model. Three lasers were compared for the ability to generate a reproducible wound: an erbium-YAG, a high-powered excimer, and a low-powered excimer laser. Reepithelialization ability was tested using newborn and adult skin keratinocytes, adult esophageal keratinocytes, and cdk4-overexpressing newborn keratinocytes. Keratinocyte compartmentalization and basement membrane formation were assessed by immunofluorescence. The erbium-YAG and high-powered excimer laser cut reproducible wounds but left the remaining surface either discolored due to thermal damage and/or ragged; keratinocytes were unable to migrate into the wound area. The low-powered excimer laser cut reproducible wounds, leaving the cut surface intact and visibly unaltered; keratinocytes reepithelialized the wound in a collagenase-dependent manner within 3 days; and return of compartmentalization and basement membrane occurred within 14 days. The laser-wounded skin equivalent is an adjustable, reproducible partial-thickness wound model where keratinocyte biology akin to in vivo can be studied, and will be useful to study the effects of aging on wound healing.

Basement Membrane↗
PubMed1979

Predictive value for survival of lymphocytes and polymorphonuclear leukocytes in patients with sepsis.

To study their value in predicting prognosis, tests were performed on peripheral blood lymphomononuclear cells and polymorphonuclear leukocytes in 34 critically ill patients with sepsis. Intially, the number of lymphomononuclear cells was reduced by 32% compared with healthy control subjects and was 42% lower in those who died than in survivors. The values remained low in those who died. The numbers of T and B cells, determined by rosette formation using sheep and mouse erythrocytes, did not change during the period of observation. Intially, K cell activity was decreased by 48% compared with normal activity. In those younger than 65 years, K cell activity was 68% lower in patients who later died than in survivors. It returned to normal at 20 to 30 days and decreased in those who died. Polymorphonuclear leukocyte adherence was decreased by 50% compared with healthy control subjects and tended to be lower in those who died. Chemotactic migration of polymorphonuclear leukocytes and intracellular killing of Staphylococcus aureus and Pseudomonas aeruginosa were not impaired. It was concluded that the lymphomononuclear cell count, K cell activity and adherence of polymorphonuclear leukocytes were decreased in patients with sepsis and that the values were useful in predicting prognosis.

Adolescent↗
PubMed1977

Studies on the cytodynamics of experimental endometrial regeneration in the rabbit. I. Historadioautography and ultrastructure.

The kinetic and fine structural characteristics and site of origin of the resurfacing uterine lining, as well as the influence of ovarian hormonal stimuli on the reparative processes of experimentally injured endometrium in the rabbit, were studied by means of in vivo historadioautography and electron microscopy. The first-generation, resurfacing spindle-shaped cells lacked mitosis and expanded by ameboid migration. This was followed by a rapid increase in nuclear deoxyribonucleic acid synthesis, which presumably provided for accelerated mitosis-mediated surface epithelial proliferation and maturation. By Day 3 after injury, endometrial regeneration was completed with a return of labeling index to base-line levels. The newly formed surface lining was derived exclusively from the persistent surface epithelium bordering the denuded regions. The isotope uptake and morphologic alterations of the regenerating endometrium in castrated rabbits which were similar to those of intact rabbits suggest that endometrial repair is not mediated by the hormones of the reproductive system.

Animals↗
PubMed1978

Acetylcholinesterase resynthesis after DFP poisoning; histochemical and biochemical study.

DFP (0.4 to 2.0 mg/kg) was injected into the rat spinal ganglion leads to N. ischiadicus model system and examinations were made of the AChE inhibitory affect and the influence on the transport and resynthesis of the enzyme. It was concluded that the intraganglionically administered DFP inhibits the enzyme activity of the pseudo-unipolar large ganglion cells, but the specific ChE remains in some of the small neurones. Autoradiographically, 3H-DFP could be demonstrated at the same morphological sites as the AChE histochemically. The labelled material migrates from the perikaryon towards the axon terminal by slow transport (10 mm/24 h). The intraganglionically administered DFP inhibits (96%) the AChE activity of the spinal ganglion. However, the enzyme activity of the ganglion cells begins to return 3 h later, and in 12 h it has attained 27% of the original activity. The enzyme undergoing transport from the perikaryon displays a proximo-distal gradient in the axon, and hence the results do not support the hypothesis of local axonal synthesis of AChE.

Acetylcholinesterase↗
PubMed1997

Acute dyslipoproteinemia induced by interleukin-2: lecithin:cholesteryl acyltransferase, lipoprotein lipase, and hepatic lipase deficiencies.

Recombinant human interleukin-2 (rIL-2) is used to treat refractory cancers. During such treatment, patients develop severe hypocholesterolemia along with striking alterations in the concentration and composition of the circulating lipoproteins. The present study was undertaken to gather information about the pathogenesis of these abnormalities. Patients were studied before-, during- and after a 5-day course of high dose i.v. rIL-2. Whole plasma cholesterol was markedly reduced by rIL-2 administration (52%; P < 0.001), whereas the triglyceride concentration did not change. Thus, the lipoproteins became triglyceride enriched (P = 0.004). Low density lipoprotein cholesterol, apolipoprotein B (apoB), high density lipoprotein cholesterol, and apoA-I concentrations all decreased. Esterified cholesterol levels were markedly reduced. Total plasma apoE increased markedly, and two kinds of abnormal particles appeared: 1) beta-migrating, very low density lipoproteins; and 2) discoidal, apoE- and phospholipid-containing particles with abnormal density and electrophoretic mobility. The activities of two lipoprotein triglyceride hydrolases, lipoprotein lipase and hepatic lipase, fell significantly during treatment and returned promptly to pretreatment levels after rIL-2 was discontinued. Lecithin:cholesteryl acyltransferase (LCAT) activity also decreased significantly (64%) during treatment, but in contrast to the lipases, remained low for at least 5 days after the last dose of rIL-2 (P < 0.001). High dose i.v. rIL-2 induces severe dyslipidemia with deficiencies of both postheparin lipases and acute LCAT deficiency. Most, if not all, of the lipoprotein changes observed are explained by the LCAT deficiency that follows IL-2-induced hepatocellular injury and cholestasis.

Apolipoprotein A-I↗
PubMed1977

Biological investigations of higher and lower plants aboard Soyuz 19.

Biological investigations carried out aboard Soyuz 19 consisted of three independent complex experiments. All biological materials aboard the spacecraft were kept in "Biocat" thermostats which maintained the required temperature. The objective of the experiment "Genetic investigations" was to determine the effect of space flight factors on the heredity of lower (Chlamydomonas reinhardi Dang) and higher (Crepis capillaris (L) Wallr and Arabidopsis thaliana (L) Heynh) plants, and on the radiosensitivity of plant seeds and the radiation effect of prior gamma-irradiation. The space flight factors decreased the survival of Chlamydomonas cells and A. thaliana plants of the first generation. They decreased the germination of seeds, increased the rate of chlorophyll mutations and embryonal lethals, produced no effect on the rate of visible mutations in unicellular algae, increased the rate of chromosome aberrations in root meristem cells C. capillaris, induced disturbances in mitosis of unicellular algae and modified the effect of prior gamma-irradiation. The experiment "Growth of micro-organisms" was conducted with a culture of Proteus vulgaris in a growth chamber. After return to the laboratory the experimental and control variants were studied for twenty-two tests. The control and experimental material differed in the average cell size, biomass distribution, the character of haemotaxis, the rate of cell migration over the substratum surface, dehydrogenase activity, ribosomal aggregation, and ultrastructural peculiarities of cells. The experiment "Embryological investigations" was carried out to study the effect of space flight factors on embryogenesis of the bony fish Brachyodanio rerio. No abnormalities were noted in the course or rate of the development of spawn cultivated in a special thermostat.

Animals↗
PubMed1989

Effect of epidermal growth factor on healing of corneal endothelial cells in cats.

Epidermal growth factor was injected intracamerally into the anterior chamber of the right eye of 9 cats. The central portion of the cornea in 8 of the 9 cats that had been cryoinjured. Effect of epidermal growth factor on the repair of endothelial cells in cats was evaluated by endothelial specular microscopy. Endothelial cell density and corneal thickness were studied quantitatively, as a measure of endothelial cell function. The repair process also was evaluated qualitatively by studying morphologic changes, developing as a result of reendothelialization and return to normal function. Seemingly, differences between rate of healing of cryoinjured eyes injected with epidermal growth factor and that in nontreated eyes were not significant (P = 0.86). The endothelial repair process was characterized by enlargement and migration of adjacent noninjured cells.

Animals↗
PubMed1987

Desensitization of the acute inflammatory response in skin and mammary gland of sheep.

Desensitization of the inflammatory response was investigated in the mammary glands and skin of sheep. Following twice daily stimulation of non-lactating glands, neutrophil concentrations in inflammatory exudates during the seventh response to endotoxin (1 microgram) and zymosan-activated plasma (1 ml) were 30% and 20% and those in primary responses occurring concurrently in contralateral glands. Cross-desensitization of ZAP was found in non-lactating glands pretreated with endotoxin. In lactating glands, inflammatory responses were examined following daily infusion of endotoxin (1 microgram) and oyster glycogen (50 mg). The neutrophil influx following infusion of each agent declined linearly, with the fourth response being 16% of the first response for both agents. On Day 5, inflammatory responses in contralateral glands receiving an initial challenge were comparable with primary responses on Day 1 in repeatedly stimulated glands. Thus, desensitization was a local phenomenon restricted to the restimulated gland. The return of normal responsiveness to 1 microgram endotoxin occurred after 9 days in glands desensitized by infusion of a single dose of 50 micrograms endotoxin. Accumulation of neutrophils and leakage of plasma were examined in skin sites restimulated with endotoxin and oyster glycogen. Neutrophil accumulation in restimulated lesions was comparable to primary lesions after about 3.5 days for endotoxin and 4.5 days for oyster glycogen. On the other hand, plasma leakage did not return to normal until Day 8 for endotoxin and until after Day 10 for oyster glycogen. The dissociation between neutrophil accumulation and plasma leakage in restimulated skin lesions contrasts with the dependence of plasma leakage on neutrophil migration reported in primary inflammatory lesions. The results suggest that desensitization of the inflammatory response may influence the pathogenesis of bacterial infection.

Acute Disease↗
PubMed1990

Caribbean international circulation: are Puerto Rican women tied-circulators?

Aspects of migration between Puerto Rico and the United States are explored. "This examination of the multiple-movement behaviour of a sample of Puerto Rican women seeks to unravel the relations between their circulation patterns, their family and contextual situations and their declared motives for undertaking international mobility. The leading question asked in this study is whether this international mobility behaviour of Puerto Rican women is autonomous or dependent upon the movement or decision-making of others. Structural theory suggests the latter is most likely, but behavioural divergence occurs in return movement."

Americas↗
PubMed1999

Redox and activation status of monocytes from human immunodeficiency virus-infected patients: relationship with viral load.

Monocytes are precursors of tissue macrophages, which are major targets of human immunodeficiency virus type 1 (HIV-1) infection. Although few blood monocytes are infected, their resulting activation could play a key role in the pathogenesis of HIV disease by modulating their transendothelial migration and inducing the production of reactive oxygen species (ROS). ROS participate in chronic inflammation, HIV replication, and the apoptosis of immune system cells seen in HIV-infected subjects. Published data on monocyte activation are controversial, possibly because most studies have involved monocytes isolated from their blood environment by various procedures that may alter cell responses. We therefore used flow cytometry to study, in whole blood, the activation and redox status of monocytes from HIV-infected patients at different stages of the disease. We studied the expression of adhesion molecules, actin polymerization, and cellular levels of H2O2, Bcl-2, and thioredoxin. Basal H2O2 production correlated with viral load and was further enhanced by bacterial N-formyl peptides and endotoxin. The enhanced H2O2 production by monocytes from asymptomatic untreated patients with CD4(+) cell counts above 500/microliter was associated with a decrease in the levels of Bcl-2 and thioredoxin. In contrast, in patients with AIDS, Bcl-2 levels returned to normal and thioredoxin levels were higher than in healthy controls. Restoration of these antioxidant and antiapoptotic molecules might explain, at least in part, why monocyte numbers remain relatively stable throughout the disease. Alterations of adhesion molecule expression and increased actin polymerization could play a role in transendothelial migration of these activated monocytes.

Adult↗
PubMed1996

Chemotactic factors stimulate CD18-dependent canine neutrophil adherence and motility on lung fibroblasts.

The mechanisms by which neutrophils migrate through the alveolar interstitium during acute lung inflammation are unknown. We wished to determine whether platelet-activating factor (PAF) and IL-8, two important mediators in neutrophil transendothelial migration, stimulated neutrophil adherence and motility on lung fibroblasts. Canine fibroblasts grown from lung explants were characterized by light and electron microscopy, and flow cytometry. Unstimulated neutrophils adhered poorly (less than 2%) to cultured fibroblasts. However, neutrophils stimulated with PAF (20-200 nM) showed a dose-dependent increase in adherence that was largely (70%) mediated by the beta 2 (CD11/CD18) integrins; adherence was less dependent (50%) on fibroblast intercellular adhesion molecule-1. Conversely, neutrophils stimulated with canine rIL-8 did not increase their adherence to fibroblasts. PAF-stimulated neutrophils were nonmotile on the surface of the fibroblast, but subsequent addition of rIL-8 (10(-8) M) induced motility that was entirely CD1 8 dependent. Fibroblasts stimulated with human rTNF-alpha or Escherichia coli endotoxin (LPS) were a significant source of IL-8 mRNA. In response to rTNF-alpha (50 U/ml), IL-8 mRNA was detected at 2 h by northern blot analysis; it peaked at 6 h and returned to baseline by 24 h. Fibroblasts stimulated with rTNF-alpha secreted IL-8 protein into the culture medium; secreted IL-8 was chemotactic for neutrophils. These data suggest that fibroblasts can function not only as an adhesive substrate, but also as a source of stimulation for neutrophil migration through the inflamed alveolar interstitium.

Animals↗
PubMed1995

Borrelia burgdorferi upregulates expression of adhesion molecules on endothelial cells and promotes transendothelial migration of neutrophils in vitro.

The accumulation of leukocytic infiltrates in perivascular tissues is a key step in the pathogenesis of Lyme disease, a chronic inflammatory disorder caused by Borrelia burgdorferi. During an inflammatory response, endothelial cell adhesion molecules mediate the attachment of circulating leukocytes to the blood vessel wall and their subsequent extravasation into perivascular tissues. Using cultured human umbilical vein endothelial cells (HUVEC) in a whole-cell enzyme-linked immunosorbent assay, we demonstrated that B. burgdorferi activated endothelium in a dose- and time-dependent fashion as measured by upregulation of the adhesion molecules E-selectin, vascular cell adhesion molecule 1 (VCAM-1), and intercellular adhesion molecule 1 (ICAM-1). As few as one spirochete per endothelial cell stimulated increased expression of these molecules. Expression of E-selectin peaked after spirochetes and HUVEC were coincubated for 4 h and returned to near-basal levels by 24 h. In contrast, expression of VCAM-1 and ICAM-1 peaked at 12 h and remained elevated at 24 h. HUVEC monolayers cultured on acellular amniotic tissue were used to investigate the consequences of endothelial cell activation by spirochetes. After incubation of HUVEC-amnion cultures with B. burgdorferi, subsequently added neutrophils migrated across the endothelial monolayers. This process was mediated by E-selectin and by CD11/CD18 leukocytic integrins. The extent of migration depended on both the number of spirochetes used to stimulate the HUVEC and the length of the coincubation period. These results raise the possibility that B. burgdorferi induces a host inflammatory response and accompanying perivascular damage through activation of vascular endothelium.

Borrelia burgdorferi Group↗
PubMed2006

Round-trip catadromous migration in a Japanese amphipod, Sternomoera rhyaca (Gammaridea: Eusiridae).

We conducted a field study of the life cycle of the eusirid gammaridean amphipod Sternomoera rhyaca Kuribayashi, Mawatari, and Ishimaru, 1996 in a stream at Gokibiru, Hokkaido, Japan over the course of two non-consecutive years. This species is biennial; it spends most of its life in freshwater, but undertakes a short catadromous migration to the sea for reproduction. Reproduction occurs from March-June. Mature adults drift downstream to the sea singly and in precopulating pairs. Copulation and oviposition in the marsupium occur in mixed water at the stream mouth. Males die after copulation; ovigerous females return upstream by walking or swimming, where their eggs develop and hatch, after which the females also die. Juveniles remain in the stream, growing until they reach sexual maturity. Laboratory experiments showed that survivorship of all stages was lowest in seawater and highest in freshwater, though juveniles survived equally well in mixed water (50% seawater) and freshwater. Eggs developed to hatching only in freshwater; hatchlings in seawater and mixed water died within one and 21 days, respectively. Thus, S. rhyaca is well adapted to freshwater. Indeed, the only stages that required elevated salinity were copulation and subsequent oviposition, and we speculate that freshwater inhibits the female pre-reproductive molt. Because the life cycle of S. rhyaca has the most ontogenetically and temporally restricted saltwater phase known in any catadromous animal, its origin and maintenance are of evolutionary interest. We discuss two alternative hypotheses for the origin of the migratory life cycle, and discuss its maintenance in terms of fitness costs and benefits.

Amphipoda↗
PubMed1984

Studies on the lymphocytes of sheep. IV. Migration patterns of lung-associated lymphocytes efferent from the caudal mediastinal lymph node.

Small lymphocytes from the efferent lymph of the caudal mediastinal lymph node (CMLN), the regional node of the lower respiratory tract, were labelled in vitro either with 51Cr, or with the fluorochrome rhodamine isothiocyanate. The labelled lymphocytes were washed and returned to the sheep by intravenous (i.v.) injection; their later appearance in the lymph from the CMLN was monitored, as was their appearance in lymph from either a peripheral somatic lymph node (PSLN) or the intestinal lymph duct. It was found that the labelled lymphocytes entered the lymph from the CMLN and PSLNs with equal facility but were significantly less able to enter the intestinal lymph. Similarly, the large lymphocytes (immunoblasts) which were released into the lymph after antigenic stimulation of the CMLN, and which were labelled in vitro with [125I]Udr, showed little tendency to enter the gut after i.v. injection and became distributed throughout the body in the same way as immunoblasts efferent from the PSLN, i.e. they went principally to the lungs, and spleen.

Animals↗
PubMed1986

Rabbit beta-migrating very low density lipoprotein increases endothelial macromolecular transport without altering electrical resistance.

Rabbit aortic endothelial cells (RAEC) were grown on micropore filters in a new device. This system allowed in situ measurement of transendothelial electrical resistance (TEER). The monolayers demonstrated a TEER of 14 +/- 1 omega X cm2 at confluence. No difference was seen in the transport of low density lipoproteins (LDL) across endothelial cell monolayers obtained from normal or Watanabe heritable hyperlipidemic rabbits, indicating that the LDL receptor was not involved in the LDL transport. TEER was inversely correlated with 22Na transport (r2 = 0.93, P = less than 0.001) but not with 125I-LDL transport. The amount of LDL transported at 15 degrees C or across glutaraldehyde-fixed monolayers was half that of the controls at 37 degrees C. Preincubation of the monolayers with rabbit beta-migrating very low density lipoproteins (beta-VLDL) increased cholesterol content by 65%, and the transport of albumin and LDL doubled without a change in TEER. Removal of beta-VLDL from the culture medium resulted in the return of cellular cholesterol content and LDL transport to control values. We conclude that preincubation of RAEC with beta-VLDL resulted in an increased permeability to LDL and albumin, and that beta-VLDL may promote increased transendothelial transport of macromolecules in cholesterol-fed rabbits.

Albumins↗