Experimental studies of membrane tethers formed from human neutrophils

Membrane tethers (thin, cylindrical pieces of membrane) have been implicated in the rolling of neutrophils along the endothelium. In our studies, these tethers were formed from passive, stimulated (0.1 M fMLP), and osmotically swollen (170–180 mOsm) human neutrophils; as well as neutrophils treated with 0.3 M latrunculin A to disrupt the cytoskeleton. This tether formation was accomplished by micropipette suction of latex beads coated with antibodies to proteins on the neutrophil membrane surface. From plots of force versus velocity for the tether formation process, we calculated adhesion energies per unit area of the lipid membrane to the cytoskeleton and the viscous resistance (effective viscosity) that occurs during the formation of these tethers at finite velocity. Most of the properties of the neutrophil were altered once it had been treated as described above. We were also able to show mechanical reversibility of membrane tethers, as well as an unexpected formation rate at high tether forces. Since membrane tethers have been implicated in the rolling of neutrophils, then the changes in tether formation may ultimately alter how these cells roll. © 2002 Biomedical Engineering Society. PAC2002: 8716Dg     

Human V5/MT+: comparison of functional and cytoarchitectonic data

To date, the delineation of the human visual “motion area” still relies on functional paradigms originally devised to identify monkey area MT. Using fMRI, we have identified putative human area V5/MT+ in normals by modelling the BOLD responses to alternating radially moving and stationary dot patterns. Functional activations were compared with cytoarchitectonic probability maps of its putative correlate area hOc5, which was calculated based upon data from histological sections of ten human post-mortem brains. Bilateral visual cortex activations were seen in the single subject dynamic versus stationary contrasts and in the group random-effects analysis. Comparison of group data with area hOc5 revealed that 19.0%/39.5% of the right/left functional activation was assigned to the right/left hOc5. Conversely, 83.2%/53.5% of the right/left hOc5 was functionally activated. Comparison of functional probability maps (fPM) with area hOc5 showed that 28.6%/18.1% of the fPM was assigned to hOc5. In turn, 84.9%/41.5% of the area hOc5 was covered by the respective fPM. Thus, random-effects data and fPMs yielded similar results. The present study shows for the first time the correspondence between the functionally defined human V5/MT+ and the post-mortem cytoarchitectonic area hOc5.     

Interaction of immunoglobulin with actin

Actin can form specific, direct associations with immunoglobulin resulting in soluble complexes or cross-linked matrices. This interaction can be detected by four in vitro assays using purified components: (1) actin enhances the cytophilic activity of guinea pig IgG2; (2) in solutions of low ionic strength, actin and IgG2 co-precipitate: (3) soluble complexes exist in 0.1 M KCl as revealed by the displacement of actin from its expected sedimentation pattern in a gradient of sucrose when in the presence of IgG 1, IgG2, or IgM; (4) immunoglobulin (IgG1, IgG2, BGG)‡: increases the viscosity of F-actin solutions, presumably by crosslinking F-actin filaments. These data suggest that direct interaction of a cytoskeletal protein with a cell surface receptor is possible.     

A pilot study of recombinant interferon beta (IFN-βser) in patients with recurrent glioma

Recombinant interferon beta (IFN-_ser) has been administered by intravenous bolus injection three times weekly at a dose of 90 × 10⁶ IU to 14, patients with recurrent malignant glioma in an ongoing study. The treatment period has ranged from 1 to 40 weeks. The most common adverse experiences were fever, chills, malaise, and headache. Fever, chills and headache were worse with the first two doses and were usually relieved with acetaminophen. All patients tolerated subsequent treatments without any difficulties. No neurologic or hematologic toxicities were observed. Of ten evaluable patients, five had progressive disease in 4 to 8 weeks; three had stable disease for 12 to 21 weeks; one has had a minor response for 13 weeks; and one has had a complete resolution of tumor for 150 + weeks. IFN-_ser appears to have activity in human glioma and is well tolerated at this dosage and schedule.     

The effect of recombinant human erythropoietin therapy on red cell expansion during autologous blood donation

As the result of the institution of coordinated programs involving regional blood centers, hospital blood banks, information services, and physicians, preoperative autologous blood donation, a previously underutilized practice, has become a standard of care in a number of elective surgical procedures. In addition, the administration of recombinant human erythropoietin has been shown to facilitate the collection of autologous blood from patients scheduled for elective orthopaedic surgery. An analysis of the findings in a study of 263 orthopaedic surgical patients in which the relationship between autologous blood ordering, collection and storage, and subsequent blood transfusion was studied indicates that both blood ordering and blood procurement practices are significant factors with regard to allogeneic blood exposure.     

Munchausen syndrome by proxy and factitious illness: Symptomatology,parent-child interaction,and psychopathology of the parents

The term Munchausen syndrome by proxy is used to diagnose children presenting symptoms of an organic disorder resulting from manipulations initiated by their caretakers. Even in early infancy it happens that injuries are induced, and that drugs, poisons or medicine are administered in order to provoke and feign clinical symptoms of severe diseases. Exact data on prevalence are not available but it is obvious that Munchausen syndrome by proxy is a rare psychiatric disorder. There is a body of evidence that Munchausen syndrome by proxy is nothing but the extreme of a broader clinical entity for which the term factitious illness has been introduced. In this group children are included whose mothers invent a history of disease in order to produce symptoms without actually damaging their children. It is not well established whether such a distinction is necessary and whether there are differences in long-term outcome. Onset of symptoms is as early as three weeks up to twelve years, and mean age of diagnosis according to a more comprehensive study is 3 1/4 year. The estimated mortality rate of children with Munchausen syndrome by proxy is 9 percent. In three of the four cases of children reported here clinical presentations were dominated by symptoms of central nervous disorders. All mothers showed unsure and inconsistent parental behaviour and inefficient coping. None of them received support from their partners, if present. In interaction the children always wanted to dominate their mothers. The high amount of personality disorders observed in the caretakers might be the reason for the often reported failure of psychotherapeutic interventions.

---

Zusammenfassung Die Diagnose Münchhausen Stellvertreter Syndrom wird bei Kindern gestellt, die Symptome einer organischen Erkrankung zeigen, die durch Manipulationen von Eltern oder anderen Sorgeberechtigten hervorgerufen werden. Vielfach werden bereits im frühen Kindesalter den Kindern Verletzungen beigebracht, Drogen, Gifte oder Medikamente verabreicht, um die klinischen Merkmale schwerer Erkrankungen vorzutäuschen. Obwohl genaue Angaben zur Häufigkeit fehlen, kann man insgesamt von einer seltenen Störung ausgehen. Es gibt zahlreiche Hinweise dafür, daß es sich beim Münchhausen Stellvertreter Syndrom um die seltene, aber sehr schwere Ausprägungsform in einer größeren Gruppe von Störungen gleichartigen klinischen Bildes handelt, für die man den Begriff der vorgetäuschte Störungen geprägt hat. In dieser Gruppe werden auch die Kinder erfaßt, deren Mütter ausschließlich Symptome und eine zugehörige Krankheitsgeschichte erfinden, die aber keine körperlichen Eingriffe (einschließlich Drogen- und Medikamentenverabreichung) vornehmen, um organische Symptome zu simulieren. Unklar ist, ob eine solche Unterscheidung notwendig und hilfreich ist. Bisher fehlen Hinweise auf Unterschiede in der Prognose im Langzeitverlauf zwischen den Untergruppen. Die Symptomatik eines Münchhausen Stellvertreter Syndroms konnte bereits bei Kindern im Alter von 3 Wochen beobachtet werden und wurde noch bei 12jährigen gefunden. In einer größeren Studie wurde ein mittleres Alter von 3 3/4Jahren für den Zeitpunkt der Diagnosestellung ermittelt. Die Sterblichkeitsrate wird auf 9 Prozent geschätzt. Bei den vier Kindern, über deren Symptomatik hier berichtet wird, standen bei drei zentralnervöse Störungen im Vordergrund. Drei Mütter gaben zusätzlich den Verdacht des sexuellen Mißbrauchs ihrer Kinder an. Die motivationalen Aspekte lassen deudiche Unterschiede erkennen. Bei drei Müttern bestand der Wunsch nach Schutz des Kindes vor realem oder vermeintlichem sexuellem Mißbrauch des Kindes. Alle Mütter hatten mindestens eine gescheiterte eheliche Beziehung. Im Erziehungsverhalten wirkten sie unsicher, inkompetent und inkonsistent; von ihren Partnern, sofern vorhanden, erhielten sie keine erzieherische Unterstützung. In der Mutter-Kind Interaktion vermochten die Kinder über die Mütter zu dominieren. Der hohe Anteil an Persönlichkeitsstörungen bei den hier beschriebenen Sorgeberechtigten könnte der Grund für das häufig berichtete Scheitern psychotherapeutischer Interventionen sein.

---

Résumé On parle de Syndrôme de Munchausen par procuration chez des enfants, qui présentent des troubles organiques résultant de manipulations de leurs responsables éducatifs. Des blessures, l'administration de médicaments, de drogues ou de poison — même chez des enfants très jeunes — ont pour effet de provoquer et simuler un tableau clinique sévère. Il s'agit d'un désordre psychiatrique rare — les chiffres exacts de prévalence sont difficiles à évaluer. Le Syndrome est décrit chez l'enfant à partir de l'âge de trois semaines jusqu'à 12 ans. L'âge moyen est de trois ans et quart. La mortalité chez les enfants porteurs d'un syndrome de Munchausen par procuration est estimé à 9%. Dans trois des quatre cas présentés le tableau clinique est dominé par des symptômes d'ordre neurologique. De manière supplémentaire trois mères rapportent un abus sexuel de leurs enfants. Les mères se caracterisent par leur incompétence et inconséquence éducative; souvent elles sont sans soutien éducatif de leur partenaire. Dans l'interaction mère — enfant les enfants ont un comportement dominant envers leur mère. La non-efficacité des interventions psychothérapeutiques peut être liée a un pourcentage élevé de troubles de la personnalité chez les parents.

     

Treatment guidelines for primary nonretentive encopresis and stool toileting refusal

Nonretentive encopresis refers to inappropriate soiling without evidence of fecal constipation and retention. This form of encopresis accounts for up to 20 percent of all cases. Characteristics include soiling accompanied by daily bowel movements that are normal in size and consistency. An organic cause for nonretentive encopresis is rarely identified. The medical assessment is usually normal, and signs of constipation are noticeably absent. A full developmental and behavioral assessment should be made to establish that the child is ready for intervention to correct encopresis and to identify any barriers to success, particularly disruptive behavior problems. Successful interventions depend on the presence of soft, comfortable bowel movements and addressing toilet refusal behavior. Daily scheduled positive toilet sits are recommended. Incentives may be used to reinforce successful defecation during these sits. A plan for management of stool withholding should be agreed on by the parents/caretakers and the family physician before intervention.