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PubMed1983

Thymus cell differentiation and in vivo T-cell migration. I. Migration of lectin-selected thymocytes.

The in vivo quantitative distribution and tissue positioning of mouse thymocytes selected in vitro by Lyt phenotype and lectin binding properties were examined. Lyt 1+2- thymocytes were selected for by cytotoxic elimination; peanut agglutinin (PNA) and soybean agglutinin (SBA) binding and nonbinding thymocyte fractions were separated by an agglutinin technique. Selected cell suspensions were labelled in vitro with 51chromium (51Cr) or [3H]adenosine. Labeled washed cells were injected intravenously into syngeneic recipients which were killed at 1, 24 or 48 hr. In recipients of 51Cr-labeled cells, tissues were collected for gamma counting, and the overall percentage recovery of injected radiolabel from the various tissues was assessed. Tissues collected from recipients of [3H]adenosine-labeled cells were fixed, sectioned, and processed for autoradiography; the positioning of labeled cells within the tissues was determined. Selected Lyt 1+2-, PNA-, and SBA- sets all showed significantly enhanced entry into lymph nodes and intestinal lymphoid tissues. Entry of SBA+ cells into these tissues was comparable to that of peripheral T cells. PNA- and SBA- selected sets, but not Lyt 1+2- selected cells, also showed increased localization to the spleen and lungs, and decreased localization to the liver. By autoradiography, PNA- cells entered lymphoid tissues much more than PNA+ cells, and at 1 hr fewer PNA+ cells in spleen were associated with lymphoid follicles. At 24 and 48 hr almost all labeled cells in lymphoid tissues were positioned in T-dependent areas. These results suggest that enrichment for thymocyte subpopulations described as "mature" also enriches for cells with the ability to enter lymphoid tissue. They also suggest that interactions at other tissue sites are important in the determination of in vivo migration, and that surface carbohydrate composition is an important factor in this determination.

Animals↗
PubMed1984

The migration of larval Toxocara canis in mice. I. Migration through the intestine in primary infections.

Toxocara canis second stage larvae (L2) hatched in the stomach of mice and within 2 h reached all parts of the small intestine, the posterior half being the preferred site for larval penetration. Following penetration at the base of crypts of leiberkuhn they followed tortuous routes in the lamina propria, and entered the tunica muscularis obliquely. Larvae only appeared to be arrested in their migration in the submucosa and lamina propria by an inflammatory reaction composed mainly of lymphocytes and eosinophils. Larvae were seen entering and within lymphatic vessels as well as the peritoneal cavity and invasion of the vascular system followed though actual penetration of intestinal blood vessels was not seen. Proteolytic enzyme activity was detected in culture media in which L2 larvae were maintained.

Animals↗
PubMedDate not supplied

Migration from plasticized films into foods. 2. Migration of di-(2-ethylhexyl)adipate from PVC films used for retail food packaging.

A UK survey of di-(2-ethylhexyl)adipate (DEHA) levels in retail foods (83 samples) wrapped in plasticized PVC film has been carried out, examining a wide range of different food types obtained from retail and take-away outlets. Foodstuffs analysed included fresh meat and poultry, ready-cooked poultry, cheese, fruit, vegetables and baked goods such as cakes, bread rolls and sandwiches. Analysis by stable isotope dilution GC/MS showed DEHA levels ranging from 1.0 to 72.8 mg/kg in uncooked meat and poultry, 9.4 to 48.6 mg/kg in cooked chicken portions, 27.8 to 135.0 mg/kg in cheese, less than 2.0 mg/kg in fruit and vegetables and 11 to 212 mg/kg in baked goods and sandwiches. The level of DEHA migration correlated with the extent of contact between the film and exposed fatty portions of the food, whether that was the mayonnaise filling of a sandwich or the surface fat from a joint of uncooked meat. The level of DEHA in meat exposed to plasticized film was not reduced significantly by volatilization or chemical transformation on subsequent cooking by grilling or frying.

Adipates↗
PubMed1968

Migration of lymphocytes and thymocytes in the rat. I. The route of migration from blood to spleen and lymph nodes.

The cellular deficit in rats thymectomized at birth is primarily one of circulating small lymphocytes. The lymphocyte deficiency is similar to that induced in adult rats by chronic drainage from a thoracic duct fistula. In both cases, the animals show a reduction of small lymphocytes in peripheral blood, thoracic duct lymph, and in circumscribed areas of lymphoid tissue. The lympocyte deficiency in lymphoid tissue can be corrected by an intravenous injection of thoracic duct lymphocytes. The evidence suggests that the deficiency is corrected by small lymphocytes. Small lymphocytes pass from blood to lymphoid tissue along a route which includes the marginal sinus in splenic white pulp and postcapillary venules in the cortex of lymph nodes and Peyer's patches. Neither the ability of small lymphocytes to colonize lymphoid tissue nor their ability to traverse postcapillary venules are thymus-dependent phenomena. However, movement of small lymphocytes across postcapillary venules appears to modify the structure of endothelium. Intravenously injected small thymocytes migrate to lymphoid tissue in smaller numbers than small lymphocytes inoculated by the same route. The few thymocytes which localize in lymphoid tissue follow the same pathway as circulating small lymphocytes.

Animals↗
PubMed1983

The migration of lymphocytes across specialized vascular endothelium VII. The migration of T and B lymphocytes from the blood of the athymic, nude rat.

The primary migration of lymphocytes from the blood was compared in nude rats and in euthymic rats. The flatter endothelium in the post-capillary venules (PCV) in the lymph nodes of nude rats was as efficient as the high endothelium of PCV in euthymic rats at capturing both T and B lymphocytes from the blood, although lymphocytes took a longer time to cross the PCV wall in nude recipients. The organ distribution of both lymphocytes and lymphoblasts ([125I]UdR-labelled cells) was broadly similar in nude and euthymic recipients. A second aim was to compare B and T lymphocytes with respect to the rate and sites at which they leave the blood after intravenous injection. As judged by sampling venous blood, B lymphocytes left the blood faster, but this was partly attributable to a larger intravascular pool of B lymphocytes in small blood vessels, especially in the lung. Thoracic duct lymphocytes from nude rats collected under standard conditions (16 h, O degrees C) entered the cervical lymph nodes very poorly, but when lymphocyte transfer was performed under more physiological conditions entry of B lymphocytes into lymph nodes was about half that of T lymphocytes. B lymphocytes did show a slight preference for entry into Peyer's patches compared with lymph nodes.

Animals↗
PubMed1993

Neutrophil sequestration and migration in localized pulmonary inflammation. Capillary localization and migration across the interalveolar septum.

Recent studies have raised the possibility that biophysical properties of the neutrophil, specifically cell size and deformability, along with the unique hemodynamic properties of the pulmonary microvasculature may be important determinants of neutrophil transit through the lung and lead to significant retention in capillaries. Additionally, accumulating evidence supports the concept that leukocytes may emigrate into inflammatory lesions through the pulmonary capillary wall, quite unlike the situation in the systemic circulation where the predominant site of margination and emigration is the postcapillary venule. To confirm and extent this suggestion, morphometric techniques were employed to determine the location and kinetics of neutrophil movement from the vascular compartment to the alveolar space in response to an inflammatory reaction initiated by local instillation of fragments of the activated form of the fifth component of complement (C5f). We found that the site of neutrophil sequestration and probable migration was almost exclusively the capillary. Neutrophil sequestration appeared first in the capillaries of the interalveolar septae, with negligible accumulation in arterioles and venules (less than that in interalveolar septae by a factor of 10(4) when corrected for the relevant surface areas). Accumulation in the airspaces lagged behind that in the interalveolar septa by about 60 min, placing an upper time-limit on the emigration process across the epithelial barriers. Interestingly, neutrophils samples by bronchoalveolar lavage represented only 1 to 2% of those neutrophils shown to be present in the airspaces of the lung by morphometric assessment, suggesting that bronchoalveolar lavage may sample only a subpopulation of the emigrated cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1997

Anxiety, depression and PTSD in asylum-seekers: assocations with pre-migration trauma and post-migration stressors.

BACKGROUND: Research into the mental health of refugees has burgeoned in recent times, but there is a dearth of studies focusing specifically on the factors associated with psychiatric distress in asylum-seekers who have not been accorded residency status. METHOD: Forty consecutive asylum-seekers attending a community resource centre in Sydney, Australia, were interviewed using structured instruments and questionnaires. RESULTS: Anxiety scores were associated with female gender, poverty, and conflict with immigration officials, while loneliness and boredom were linked with both anxiety and depression. Thirty subjects (79%) had experienced a traumatic event such as witnessing killings, being assaulted, or suffering torture and captivity, and 14 subjects (37%) met full criteria for PTSD. A diagnosis of PTSD was associated with greater exposure to pre-migration trauma, delays in processing refugee applications, difficulties in dealing with immigration officials, obstacles to employment, racial discrimination, and loneliness and boredom. CONCLUSIONS: Although based on correlational data derived from'a convenient' sample, our findings raise the possibility that current procedures for dealing with asylum-seekers may contribute to high levels of stress and psychiatric symptoms in those who have been previously traumatised.

Adult↗
PubMed1996

Auditory epithelial migration: I. Macroscopic evidence of migration and pathways in rat.

Auditory epithelial migration (AEM) was studied in the rat for up to 42 days following the application of dye on the tympanic membrane (TM) and external auditory canal (EAC). Migratory pathways were similar to those in the human. In the pars tensa (PT), pathways were radially and centrifugally oriented from the handle of the malleus (HM) toward the annulus. However, the pathway along the HM from the umbo to the pars flaccida (PF), as reported in the human, was not observed in the rat; instead, a shallow downward pathway along the HM. In the PF, the radial spread of dye-markings from the proximal part of the HM to the upper wall of the EAC, as found in the human, was also observed in the rat. We conclude that the TM and EAC of the rat constitute an appropriate experimental model with which to study the human type of AEM.

Animals↗
PubMed1996

Auditory epithelial migration. II: Morphological evidence for auditory epidermal cell migration in rat.

Morphology of the tympanic membrane (TM) and external auditory canal (EAC) was studied in healthy, intact rat ears. TM-perforated ears (3 days after making the perforation) and TM-perforation-healed ears (14, 28 and 42 days after making the perforation). In intact ears, the epidermis in the annular region of the EAC displayed a characteristic appearance with cytoplasmic protrusions. We termed these protrusions as "finger-like projections". In contrast to the rat, the annular region of the EAC in the guinea-pig did not show "finger-like projections". Following a perforation in the centre of the anterior or the posterior quadrant of the pars tensa in rats the "finger-like projections" disappeared from the annular region on the perforated side of the EAC, while the projections remained on the malleus side of the perforation edge. In perforation-healed ears analysed 42 days after the perforation, the "finger-like projections" had recurred in the annular region on the perforated side of the EAC. The "finger-like projections" are likely to express maturation (keratinization) and desquamation of epidermal cells in the pars tensa and also could constitute morphological evidence of their migration on the TM.

Animals↗
PubMed2000

Clustering on the forward surfaces of migrating neutrophils of a novel GPI-anchored protein that may regulate neutrophil adherence and migration.

We previously reported a novel glycosylphosphatidylinositol (GPI)-anchored glycoprotein (tentatively designated GPI-80) on human leukocytes that may be involved in the regulation of neutrophil adherence and migration. In this study, we examined by immuno- and scanning electron microscopy, the distribution of GPI-80 on neutrophil surfaces. GPI-80 was diffusely distributed on the surface of resting neutrophils and on the peripheral areas of adherent cells after stimulation with N-formyl-methionyl-leucyl-phenylalanine. After longer stimulation (60 min), GPI-80 decreased in number and was again diffusely distributed on the surfaces of round neutrophils. Few GPI-80 were detected on the ventral surfaces of adherent neutrophils. Clusters of GPI-80 were detected on the forward surfaces of neutrophils transmigrating through pores of nitrocellulose membranes. These results may give a morphological background of possible role of GPI-80 for neutrophil extravasation.

Amidohydrolases↗