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PubMed1982

Products of cultured neuroglial cells. III. Release of an 85,000 molecular weight glycoprotein by C6 glioma cells in vitro.

With [3H]fucose as a marker, C6 glioma cells in culture released an 85,000 molecular weight molecule into the medium as the major extracellular glycoprotein. The quantity and extracellular/cytoplasmic ratio of this glycoprotein suggest that its cellular processing is different from that of five other released glycoproteins of molecular weights 55,000, 115,000, 130,000, 150,000, and 170,000. Nearly 40% of newly synthesized glycoproteins in the cells was released into the culture medium. Major glycoproteins retained by the cells migrated electrophoretically to molecular weight positions of 82,000, 110,000, 120,000, 140,000, and 160,000, and approximately one-third of these returned glycoproteins were labile to trypsinization. Both synthesis and release of these macromolecules were inhibited more than 95% with cycloheximide treatment, demonstrating that nearly all fucosylation was linked to protein synthesis. Since 40% of all glycoproteins was released under conditions of more than 99% cellular viability, it is likely that these extracellular glycoproteins are physiological products of membrane turnover and secretion, but not of cell lysis. The results provide a basis for the further study of glial differentiation and of shed glioma antigens.

Animals↗
PubMed1990

The effect of surgical anaesthesia on antral motility in the ferret.

Gastric motility was recorded from ferrets chronically prepared with an antral strain gauge. In fasted animals, antral motility showed cycles of activity and quiescence typical of the migrating motor complex (MMC) with a period of 44.7 +/- 6.1 min (n = 4). Anaesthesia with pentobarbitone sodium (50 mg/kg) disrupted this interdigestive motor pattern which returned along with recovery from anaesthesia. The first cycle of antral motility occurred 119 +/- 23.9 min after the onset of anaesthesia and thereafter continued to cycle at the pre-anaesthetic interval. The recovery was unaffected by treatment with guanethidine (2 mg/kg) or naloxone (1.25 mg/kg) but all motility was prevented with atropine (100 micrograms/kg). Following chronic truncal vagotomy cycles of antral activity persisted during pentobarbitone anaesthesia. With prolonged anaesthesia with ethyl carbamate (1300 mg/kg) there was no return to antral cycling but instead continuous low amplitude regular contractions were present. The lack of MMC activity in acute experiments is thus a consequence of the anaesthesia and not the surgical interventions.

Anesthesia↗
PubMed1976

Imprinting to chemical cues: the basis for home stream selection in salmon.

Juvenile coho salmon were exposed to morpholine or phenethyl alcohol (p-alcohol) for 1 1/2 months and then released in Lake Michigan. During the spawning migration 18 months later, morpholine and p-alcohol were metered into separate streams, and the number of morpholine- and p-alcohol-exposed fish returning to each stream was determined. Seventeen other locations were also monitored. The majority of the fish exposed to morpholine were captured in the stream scented with morpholine and most fish exposed to p-alcohol were captured at the p-alcohol-treated stream. This field study demonstrates that coho salmon imprint to and utilize chemical cues for homing.

Animals↗
PubMed1994

Precocious and reversible expression of sucrase-isomaltase unrelated to intestinal cell turnover.

The effect of starvation and refeeding on the developmental pattern of intestinal sucrase-isomaltase (SI) was analyzed in preweaned rats. Starvation at postnatal day 12 caused a precocious expression of SI activity and mRNA. Alkaline phosphatase activity was slightly reduced, and no significant change was observed for aminopeptidase and lactase activities. Immunostaining showed that SI molecules appear in cells at the base of the villus. Sucrase expression was further increased by prolonged food deprivation, whereas enzyme activity as well as the amount of SI mRNA dropped to reach the low level found in control sucklings when 48 h-starved pups were refed by returning them to their dams. During the refeeding period, the enterocytes that were committed to produce SI by starvation continued to express the enzyme while migrating up the villi. However, the new epithelial cells arising from the crypts no longer synthesized the disaccharidase. The starvation-evoked appearance of SI was preceded by a transient burst of expression of the protooncogene c-fos, an event that may be correlated to the ontogenic rise of c-fos mRNA observed before weaning. However, in contrast to the normal weaning condition, SI induction by starvation occurred without obvious increase of epithelial cell proliferation and turnover. During the starvation and refeeding period, patterns of sucrase activity and SI mRNA paralleled the serum level of glucocorticoids.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed2000

Self-expanding esophageal metallic stents in the treatment of esophageal obstruction.

Esophageal obstruction from any cause is debilitating. In patients with malignant obstruction palliation to relieve pain and dysphagia is the primary goal. Conventional endoluminal prostheses allow variable palliation. Covered expandable metallic stents with an 18-mm lumen allow improved deglutition. From December 1994 through December 1998, 59 patients underwent placement of self-expanding silicone-covered esophageal stents for esophageal obstruction. There were 36 men and 23 women ranging in age from 41 to 94. All patients underwent esophageal dilation using a flexible gastroscope and Savary bougies. After dilation placement of the stent was performed under fluoroscopic control. Follow-up was complete in all patients. Technical success was achieved in all patients. There was one postoperative death (bronchopulmonary fistula), one migration of the stent requiring removal, and one recurrent obstruction. The remaining stents were well tolerated even in the cervical region (four patients). All patients returned to a diet of solid foods. We conclude that covered self-expanding esophageal metallic stents are technically simple and safe to insert and appear to provide durable excellent palliation of esophageal obstruction due to either benign or malignant conditions.

Adult↗
PubMed1999

Changes in body fluid distribution during 7 days 6 degrees head-down bed rest.

It is well known that, in a state of weightlessness, body fluids shift toward the head site, but the actual rates of the migration of fluids has never been measured. In order to identify the causes of reduced orthostatic tolerance and the reduction in circulating blood volume after returning from a space mission, it is necessary to measure the changes in body fluid distribution. Although the methods for measuring changes in body fluids include the use of isotopes or pigments, such methods cannot be employed in space due to their invasive properties. Therefore, we directed our attention toward the impedance method, for which we developed a non-invasive apparatus for measuring the distribution of body fluids. We therefore measured the actual distribution of body fluids using the bed-rest method, a model of the zero gravity state.

Abdomen↗
PubMed1991

Cytokine-activated human endothelial monolayers support enhanced neutrophil transmigration via a mechanism involving both endothelial-leukocyte adhesion molecule-1 and intercellular adhesion molecule-1.

rIL-1 beta treatment of cultured human endothelial cells (HEC) promotes polymorphonuclear leukocyte (PMN) adhesion and transmigration. Using in vitro quantitative monolayer adhesion and videomicroscopic transmigration assays, we have examined the contributions of endothelial-leukocyte adhesion molecule-1 (ELAM-1), intercellular adhesion molecule-1 (ICAM-1), and the leukocyte adhesion complex, CD11/CD18, to these processes. Maximal enhancement of PMN adhesion and transmigration were observed after 4 h of rIL-1 beta treatment, when surface expression of ELAM-1 had peaked and ICAM-1 was modestly increased. Blocking mAb directed to either ELAM-1 or ICAM-1 inhibited greater than 90% of the up-regulated PMN transmigration. Blocking mAb directed to either CD11a/CD18 (LFA-1, a ICAM-1 counter-receptor), CD11b/CD18 (Mo-1), or CD18 (common beta 2-integrin) also blocked greater than 90% of PMN transmigration. At later time points (24 or 48 h), ELAM-1 surface expression was markedly decreased, whereas ICAM-1 expression was increased over the 4-h level; PMN adhesion remained elevated (approximately 50 to 60% of 4 h level), but transmigration returned to levels seen with unactivated HEC. These data indicate that PMN interaction with at least two distinct HEC adhesion molecules is necessary for transendothelial migration and suggests that PMN adhesion and transmigration, although interrelated, are mechanistically distinct processes.

Antigens, CD↗
PubMed1983

Remote nailing of intertrochanteric and subtrochanteric fractures of the femur.

Remote nailing of intertrochanteric and subtrochanteric fractures of the femur is a definite addition to the armamentarium in the management of these injuries. The advantages of the technique are too great to ignore. The surgeon should not be misled, however, into thinking that this is an easy operation or that it represents a panacea for difficult fracture situations. Considerable time must be spent learning the operative technique, its pitfalls and complications, and the postoperative management of patients. After the operation we allow our patients early weight bearing in the knee-extended position, this being maintained by the use of a Jones bandage. We believe that the prevention of knee flexion minimizes stresses across the fracture site and prevents the tendency toward external rotation. Early external rotation deformity in the patient lying in bed may cause concern, but this tendency toward external rotation disappears as soon as the patient begins to walk and bear weight. In the patient with the fracture anatomically reduced and fixed a significant external rotation will not be a problem. The use of remote nailing does not eliminate complications in the surgical treatment of intertrochanteric fractures but merely replaces one set of complications for another. It is our belief that the complications arising from remote nailing in intertrochanteric and subtrochanteric fractures are of less severity to the patient and more easily managed by the surgeon than the more traditional complications occurring as a result of direct attack on the fracture site with the implantation of various nail plate devices. Lower blood loss, shorter operating time, decreased incidence of infection, earlier walking, extremely high rate of union, and extremely low rate of implant failure are sufficient returns for occasional shortening and occasional external rotation deformity, the two complications most frequently mentioned in the literature. Excessive deformity, failure of fixation, and pin migration either proximally or distally are attributable to poor technique (with the system) and are not inherent defects of the method itself. As a relatively unbiased observer I find praise and fault with both techniques and am not in a position to recommend one over the other for any given surgeon or any given fracture. The concept advanced by both Ender and Harris, however, is sound and if used correctly can improve the overall care of the unfortunate patient who suffers an intertrochanteric fracture of the femur.

Bone Nails↗
PubMed1994

Investigating sea turtle migration using DNA markers.

The past year has seen a further marshaling of genetic evidence for 'natal homing' in several species of marine turtles, a phenomenon wherein females, upon reaching sexual maturity, exhibit a propensity to return to nest at or near the respective beaches upon which they hatched some two or more decades earlier. This genetics-based inference stems from the strong spatial patterning observed in mitochondrial DNA lineages among nesting sites. Rookery-specific mitochondrial DNA markers are now being employed to monitor the natal sources of individuals captured at other phases of the life cycle, and the genetic findings have important conservation ramifications.

Animals↗
PubMed1990

Guests or immigrants? Contradiction and change in the German immigration policy debate since the recruitment stop.

The authors review major points in the policy debate over immigration in West Germany since the 1973 recruitment stop legislation. Special emphasis is placed on the labor force effects of migration to West Germany and their impact on migration policy. The authors find that "government immigration policy since 1973 has embraced three contradictory goals: reduce the influx of foreigners, integrate those who intend to settle in West Germany, and encourage the return of migrants who are inclined to leave. The internal contradictions between these policy goals have prevented them from being fulfilled and thereby have generated considerable frustration."

Demography↗
PubMed1983

Regulation of the fasting enterohepatic circulation of bile acids by the migrating myoelectric complex in dogs.

UNLABELLED: The purpose of this study was to correlate the fasting enterohepatic circulation (EHC) of bile acids with the migrating myoelectric complex. Four dogs were surgically provided with a functional cholecystectomy, a duodenal cannula for direct vision cannulation of the common bile duct, and 12 bipolar electrodes implanted from stomach to terminal ileum. Bile was collected in equal-volume, timed aliquots over 6 to 10 h. Aliquots were sampled and either returned to the duodenum for study of the intact EHC, or collected and retained in order to study the time course of the bile acid pool washout. In the washout experiments boluses of radiolabeled taurocholic acid were instilled into the duodenum before and after duodenal phase III of the migrating motor or myoelectric complex (MMC). In another group of experiments the bile acid pool was washed out and during a continuous duodenal infusion of taurocholic acid bile was collected to study the pattern of hepatic secretion. RESULTS: (a) In all experiments, a single broad peak of bile flow and bile acid secretion occurred at 35-55% of the MMC migration time. At this time the MMC had migrated to a point 70-85% of the distance along the small intestine. (b) During bile acid pool washout the peak of bile flow and bile acid secretion occurred with the distal migration of the first MMC and then bile flow and bile acid secretion rates decreased to a minimum and stabilized. (c) In bile acid pool washout experiments the radiolabeled bile acids instilled into the duodenum prior to duodenal phase III were secreted and peaked with peak endogenous bile acid secretion. The secretion of radiolabeled bile acids instilled into the duodenum after duodenal phase III was delayed until the subsequent cycle of the MMC. 88% of the bile acid pool collected over 6 h was secreted during the distal migration of the first MMC (2.4 +/- 0.4 h). (d) After bile acid pool washout and during continuous duodenal infusion of taurocholic acid, hepatic bile flow and bile acid secretion continued to fluctuate with the same pattern observed with the EHC intact. CONCLUSIONS: (a) In the fasting state, the transport of intestinal bile acids to the liver is pulsatile rather than continuous and is determined by the MMC. Maximum hepatic secretion occurs when phase III of the MMC propels the intraluminal bile acid pool to its site of absorption in the distal small bowel. (b) The "housekeeping" action of the MMC is very efficient and clears 88% of the 6-h washout bile acid pool in one pass.

Animals↗
PubMed1992

Centrosomes, microtubules, and microfilaments in the reendothelialization and remodeling of double-sided in vitro wounds.

The maintenance of endothelial monolayer integrity is an important function of aortic endothelial cells. Our study was designed to test two hypotheses related to the repair of the wounded endothelial monolayer. First, that the reappearance of the highly ordered cobblestone monolayer after wound closure is associated with specific sequential changes in the cytoskeletal system. Second, that there are different patterns of reendothelialization depending on whether microfilaments or microtubules are disrupted. One and a half millimeter wide wounds were created down the middle of confluent endothelial monolayers so that there were two wound edges facing each other. During the initiation of repair, the centrosomes of the cells on both sides of the wound reorientated to the front of the cell. The dense peripheral band of actin microfilaments disappeared, the cells elongated and migrated as a uniform sheet with wound closure occurring within 60 hours. The rate of closure remained constant until the migrating fronts met. The cytoskeletal changes observed and the rate of closure were similar to those we reported in a single edge wound. At closure, however, there was a transient piling up of cells which disappeared after 24 to 36 hours. Within 36 to 48 hours after closure, the centrosomes became randomly distributed around the nucleus. By 40 to 48 hours, the dense peripheral band started to reappear and the cells returned to a cobblestone appearance 72 to 96 hours after closure. Thus, the remodeling of the confluent monolayer after wound closure occurs in association with a specific series of cytoskeletal changes. When the microfilaments were disrupted with cytochalasin B, cell migration still occurred but it took up to four times longer for closure. These cells were initially flatter than normal and contained only a few microfilament fibers; however, the microtubule system was intact and centrosome reorientation occurred, but at a slower rate. However, when the microtubules were disrupted with colchicine, either at the onset of wounding or during repair, neither centrosome reorientation nor cell migration occurred. Thus wound closure of small-sized wounds require the presence of intact microtubules, whereas the additional presence of microfilaments results in a more rapid and efficient system of reendothelialzation.

Actin Cytoskeleton↗
PubMed2005

Female genital mutilation -- an exported medical hazard.

BACKGROUND: Female circumcision (FC) has remained a common practice in the countries where it has traditionally been performed. Following increased global mobility, it has also become a common medical issue in the predominantly non-Islamic countries where an increasing number of immigrants from regions where FC is still traditional, have settled. OBJECTIVES: To investigate types of FC found in a group of immigrants from northern Africa with a current domicile in Scandinavia. To characterize these women with regard to education, socio-economic status and experienced complications and sequelae. To report attitudes to FC among the women and their husbands. METHODS: An autoquestionnaire was distributed to 220 immigrant women (16-42 years old), who belonged to an African community in Scandinavia and who had all been circumcised. Information was also gathered concerning 76 of their daughters (aged 1-13 years). Of the women's husbands, 95 were asked about their attitudes to FC. RESULTS: Of the 140 women, who had been circumcised in their home country before they migrated, 78 (35%) had been clitoridectomized, 38 (17%) had been subjected to genital excision and 24 (11%) to infibulation. The corresponding percentages in the remaining women, who had had FC when returning home for a visit, were 0%, 14% and 22%, respectively. Of the daughters, 15 (19%) had been circumcised whilst living in Scandinavia; all had been clitoridectomized. Twenty-eight (13%) women reported having experienced late complications or post-FC sequelae. A positive attitude to stopping the tradition of FC was reported twice as often by the husbands (69%) as by the circumcised women (35%). Religion (95% of the responders were Muslims and 5% Christians), cultural tradition, and increased chance of marriage or of continued health were the reasons put forward in favor of the continuation of FC by 58%, 27%, 10% and 4 %, respectively. Five per cent could not supply an opinion. CONCLUSIONS: FC is performed in immigrant women even after settling in areas where this practise is legally banned. Circumcised immigrant women experience medical and sexual problems which have to be dealt with in their new domicile country. Many African Islamic women, who have migrated to Scandinavia, seem still to be in favour of the continuation of circumcision for varying reasons.

Adolescent↗
PubMed1976

Physician migration to the U.S.--foreign aid for U.S. manpower.

Data were obtained from the American Medical Association on Iranian physicians practicing in the U.S., and from the Iranian Medical Registry on U.S.-trained Iranian physicians who have returned to practice in Iran. There were 2,066 Iranian physicians practicing in the U.S. in 1972, 1,234 (60%) of whom were not undergoing any training. Only 600 of Iran's 9,535 physicians in 1972 had been trained in the United States. Thus, less than one-third of the specialists who have completed training in the U.S. have returned to practice in Iran. The specialist group with the highest rate of return is the combined surgery subspecialties (neurosurgery, thoracic surgery, orthopedic surgery, and plastic surgery). The specialist groups with the lowest rates of return were pathology, anesthesiology, and psychiatry. A comparison is made of the manpower problems Iran faces and the American problems in the area of physician manpower.

Adult↗
PubMed1980

Amyotrophic lateral sclerosis among Chamorro migrants from Guam.

Amyotrophic lateral sclerosis (ALS), which occurs in unusually high incidence among the Chamorro people on the island of Guam, has developed in 28 Chamorro migrants--24 of whom had onset in the United States, Japan, Germany, or Korea--after periods of absence from Guam of 1 to 34 years. Thus, the latency period for the disease, if caused by environmental factors on Guam, may be over three decades. Four further patients developed ALS within 1 to 14 years of their return to Guam after long-term residence in the continental United States. The minimum exposure time to environmental variables on Guam, based on age at migration, was 18 years, and all patients had spent their childhood and adolescence on Guam. Estimates of crude mortality rates for ALS from these data are considerably higher than for the United States population, and lower than the ALS mortality rates for nonmigrant Chamorros on Guam.

Adult↗
PubMed2002

Modification of acute and late-phase allergic responses to ovalbumin with lipopolysaccharide.

BACKGROUND: We have previously shown that lipopolysaccharide (LPS) exposure in sensitised animals 18 h after ovalbumin (OVA) challenge inhibits OVA-induced airway hyper-responsiveness (AHR). In the present study, we investigated the effect of LPS on OVA-induced acute and late-phase allergic responses in sensitised rats when challenged with OVA. METHODS: Rats were sensitised with OVA and 11 days later challenged with 1% OVA in the presence or absence of LPS (0.5-50 microg/ml) given in the same nebulizer. Acute responses to OVA were measured each minute for 30 min after challenge. In a separate group of animals, late-phase responses to OVA were determined at 24 h. At the end of each study, Evans blue dye was injected and animals sacrificed 30 min later. Bronchoalveolar lavage was obtained to monitor inflammatory cell migration and microvascular leakage. RESULTS: OVA challenge in sensitised animals produced an acute response with changes in lung mechanics peaking 10.0 +/- 0.9 min after OVA and returning to baseline within 30 min. This was followed 24 h later by increased responses to methacholine chloride (MCh), inflammatory cell influx and increased Evans blue leakage into the lungs. Presence of 5 or 50 microg/ml LPS in the nebulizer during OVA challenge altered the kinetics of the acute-phase response, with an immediate decrease in lung function (time to peak decreased from 10.3 +/- 1.2 to 1.8 +/- 0.2 and 2.2 +/- 0.3 min, respectively: p < 0.001, n = 6) and a dose-dependent attenuation of late-phase AHR, cellular influx (n = 5, p < 0.001) and Evans blue leakage (n = 5, p < 0.001) at 24 h. CONCLUSIONS: In summary, co-administration of OVA with LPS modifies both the acute and late-phase responses to the allergen, inducing an earlier acute change in lung function and a dose-dependent inhibition of late-phase responses to the allergen.

Acute-Phase Reaction↗
PubMed2003

Mitochondrial DNA transit between West Asia and North Africa inferred from U6 phylogeography.

BACKGROUND: World-wide phylogeographic distribution of human complete mitochondrial DNA sequences suggested a West Asian origin for the autochthonous North African lineage U6. We report here a more detailed analysis of this lineage, unraveling successive expansions that affected not only Africa but neighboring regions such as the Near East, the Iberian Peninsula and the Canary Islands. RESULTS: Divergence times, geographic origin and expansions of the U6 mitochondrial DNA clade, have been deduced from the analysis of 14 complete U6 sequences, and 56 different haplotypes, characterized by hypervariable segment sequences and RFLPs. CONCLUSIONS: The most probable origin of the proto-U6 lineage was the Near East. Around 30,000 years ago it spread to North Africa where it represents a signature of regional continuity. Subgroup U6a reflects the first African expansion from the Maghrib returning to the east in Paleolithic times. Derivative clade U6a1 signals a posterior movement from East Africa back to the Maghrib and the Near East. This migration coincides with the probable Afroasiatic linguistic expansion. U6b and U6c clades, restricted to West Africa, had more localized expansions. U6b probably reached the Iberian Peninsula during the Capsian diffusion in North Africa. Two autochthonous derivatives of these clades (U6b1 and U6c1) indicate the arrival of North African settlers to the Canarian Archipelago in prehistoric times, most probably due to the Saharan desiccation. The absence of these Canarian lineages nowadays in Africa suggests important demographic movements in the western area of this Continent.

Africa, Northern↗
PubMed2001

CCR7 expression and memory T cell diversity in humans.

CCR7, along with L-selectin and LFA-1, mediates homing of T cells to secondary lymphoid organs via high endothelial venules (HEV). CCR7 has also been implicated in microenvironmental positioning of lymphocytes within secondary lymphoid organs and in return of lymphocytes and dendritic cells to the lymph after passage through nonlymphoid tissues. We have generated mAbs to human CCR7, whose specificities correlate with functional migration of lymphocyte subsets to known CCR7 ligands. We find that CCR7 is expressed on the vast majority of peripheral blood T cells, including most cells that express adhesion molecules (cutaneous lymphocyte Ag alpha(4)beta(7) integrin) required for homing to nonlymphoid tissues. A subset of CD27(neg) memory CD4 T cells from human peripheral blood is greatly enriched in the CCR7(neg) population, as well as L-selectin(neg) cells, suggesting that these cells are incapable of homing to secondary lymphoid organs. Accordingly, CD27(neg) T cells are rare within tonsil, a representative secondary lymphoid organ. All resting T cells within secondary lymphoid organs express high levels of CCR7, but many activated cells lack CCR7. CCR7 loss in activated CD4 cells accompanies CXC chemokine receptor (CXCR)5 gain, suggesting that the reciprocal expression of these two receptors may contribute to differential positioning of resting vs activated cells within the organ. Lymphocytes isolated from nonlymphoid tissues (such as skin, lung, or intestine) contain many CD27(neg) cells lacking CCR7. The ratio of CD27(neg)/CCR7(neg) cells to CD27(pos)/CCR7(pos) cells varies from tissue to tissue, and may correlate with the number of cells actively engaged in Ag recognition within a given tissue.

Biomarkers↗