Uveal melanoma radiation. 125I brachytherapy versus helium ion irradiation

The optimum radiation therapy for uveal melanoma is uncertain. Both helium ion irradiation and 125I brachytherapy have been used to treat this neoplasm. This investigation analyzed the control and complication rates of uveal melanomas treated with helium ions of 125I plaques. In both a retrospective and a prospective dynamically balanced study, the control rates appeared to be similar. There were more posterior segment complications after 125I plaques and more anterior segment complications, including neovascular glaucoma, after helium ion irradiation. The follow-up period is too short to draw definitive conclusions on the radiation complications. Overall, approximately 89% of eyes were retained and less than 4% of treated eyes were removed because of failure to control the tumor.     

General practitioners' views on the implementation of community-led maternity care in south Camden, London.

New recommendations suggesting that maternity care should be increasingly community-based have generated concern regarding the interprofessional cooperation between general practitioners and midwives. In Camden, London, this service was expanded in 1993. Although existing joint antenatal care arrangements between GPs and midwives were not expected to alter significantly, the shift of care from hospital to community midwives, and the expansion of community-led care to women with complications, was expected to have implications for the GPs. A questionnaire-based study asked GPs who provide antenatal care about their role and liaison with other professionals. Most were satisfied with the current arrangements; only a minority felt that their workload, clinical practice, or communication with obstetric teams had altered.     

Hemorrhagic and nonhemorrhagic brain lesions: evaluation with 0.35-T fast MR imaging

Two fast magnetic resonance (MR) imaging techniques, advanced Fourier and partial-flip imaging, were used at 0.35 T to examine 21 patients with suspected intracranial lesions; the results were quantitatively compared with a conventional spin-echo study. Both of the fast MR techniques yielded a fourfold reduction in imaging time per section. The advanced Fourier sequence showed contrast that was identical to the conventional spin-echo study with signal-to-noise ratios of 58% and 57% for the first and second echoes, respectively. The partial-flip sequence showed a contrast of 109% and 57% for lesions versus substantia alba, and 107% and 78% for substantia grisea versus substantia alba relative to the first and second echoes of the conventional spin-echo study. The partial-flip sequence was particularly sensitive to magnetic susceptibility; this produced artifacts that may undermine the usefulness of partial flip for routine screening in certain parts of the brain. However, this susceptibility significantly improved the detection of intracranial hemorrhage when compared with the spin-echo sequence, particularly when combined with phase mapping of the partial-flip study.     

HPA-5b (Bra) neonatal alloimmune thrombocytopenia: clinical and immunological analysis of 39 cases

Maternal alloimmunization against fetal platelets can cause fetal and neonatal thrombocytopenia (NAIT). The HPA-1a (PIA1, Zwa) antigen is by far the most common antigen implicated in NAIT. However, today another antigen often linked with that affection is HPA-5b (Br(a)). This is a report of 39 cases of NAIT involving the HPA-5b antigen. Thrombocytopenia may be of grave consequence. Three infants developed intracerebral haemorrhages (ICH). Of these, one died presumably as a consequence of ICH. Central nervous system (CNS) sequelae in the neonatal period was observed in two children. The potential hazards of death or disabling neurologic sequelae following intracerebral haemorrhage call for rapid and reliable diagnosis and effective therapy. Because there is high risk that subsequent pregnancies might be also affected by NAIT, the mothers of a previously affected child should be managed similarly to the HPA-1b mothers (PIA2, Zwb). The antenatal diagnosis of thrombocytopenia should be made and if necessary the in utero therapy instituted.     

von Willebrand factor binding to platelet glycoprotein Ib-IX-V stimulates the assembly of an α-actinin-based signaling complex

Summary. Background: Pathological shear stress induces platelet aggregation that is dependent on von Willebrand factor (VWF) binding to glycoprotein (Gp)Ib‐IX‐V and phosphatidylinositol 3‐kinase activation. We tested the hypothesis that pathological shear stress stimulates phosphatidylinositol 3,4,5‐trisphosphate (PIP₃) synthesis by directing the assembly of a molecular signaling complex that includes class IA phosphatidylinositol 3‐kinase (PI 3‐KIA). Methods: Platelets were subjected to 120 dynes cm^?2 shear stress in a cone‐plate viscometer. Resting and sheared platelets were lyzed, immunoprecipitations of PI 3‐KIA performed, or lipids extracted for PIP₃ measurements. α‐Actinin was incubated with phosphatidylinositol 4,5‐bisphosphate (PIP₂), immunoprecipitated, and used as a substrate for in vitro PI 3‐KIA activity. Results: Pathological shear stress induces biphasic PIP₃ production. In resting platelets, PI 3‐KIA associates with α‐actinin and PIP₂. After exposure to shear stress, α‐actinin and PIP₂ rapidly disassociate from PI 3‐KIA. PI 3‐KIA then gradually re‐associates with PIP₂ and α‐actinin, and this complex becomes linked to GpIbα through the cytoskeleton. PIP₃ production and the observed changes in the association between α‐actinin, PIP₂, and PI 3‐KIA are inhibited when VWF binding to GpIbα is blocked. In a cell‐free system, α‐actinin binds PIP₂ and when the α‐actinin–PIP₂ complex is added to platelet PI 3‐KIA, PIP₃ production is stimulated. Conclusions: These results suggest that pathological shear‐induced VWF binding to GpIb‐IX‐V stimulates PIP₃ production through the assembly of an α‐actinin‐based complex that colocalizes PI 3‐KIA with substrate PIP₂.     

Interface echos between the retina and choroid

In 61 patients echographically examined in A and AB mode at Münster University Eye Hospital a membrane-like echo was found between the retina and the choroid. The acoustic characteristics were studied. The usefulness for the differential diagnosis of retinal detachment was demonstrated with several situations of the retina. The thickness of the retina and choroid can be measured in routine examinations.