Dynamics of a colloid-stabilized cream.

We use x-ray photon correlation spectroscopy to investigate the dynamics of a high-volume-fraction emulsion creaming under gravity. The dodecane-in-water emulsion has interfaces stabilized solely by colloidal particles (silica). The samples were observed soon after mixing: as the emulsion becomes compact we discern two regimes of aging with a crossover between them. The young emulsion has faster dynamics associated with creaming in a crowded environment accompanied by local rearrangements. The dynamics slow down for the older emulsion, although our studies show that motion is associated with large intermittent events. The relaxation rate, as seen from the intensity autocorrelation function, depends linearly on the wave vector at all times; however, the exponent associated with the line shape changes from 1.5 for young samples to less than 1 as the emulsion ages. The combination of ballisticlike dynamics, an exponent that drops below 1, and large intermittent fluctuations has not been reported before to our knowledge.

Bicontinuous emulsions stabilized solely by colloidal particles.

Recent large-scale computer simulations suggest that it may be possible to create a new class of soft solids, called 'bijels', by stabilizing and arresting the bicontinuous interface in a binary liquid demixing via spinodal decomposition using particles that are neutrally wetted by both liquids. The interfacial layer of particles is expected to be semi-permeable; hence, if realized, these new materials would have many potential applications, for example, as micro-reaction media. However, the creation of bijels in the laboratory faces serious obstacles. In general, fast quench rates are necessary to bypass nucleation, so that only samples with limited thickness can be produced, which destroys the three-dimensionality of the putative bicontinuous network. Moreover, even a small degree of unequal wettability of the particles by the two liquids can lead to ill-characterized, 'lumpy' interfacial layers and therefore irreproducible material properties. Here, we report a reproducible protocol for creating three-dimensional samples of bijel in which the interfaces are stabilized by essentially a single layer of particles. We demonstrate how to tune the mean interfacial separation in these bijels, and show that mechanically, they indeed behave as soft solids. These characteristics and their tunability will be of great value for microfluidic applications.

Inhibition of malignant glioma cell growth by a survivin mutant retrovirus.

Glioblastoma multiforme (GBM) is a highly malignant brain tumor that is resistant to conventional radiotherapy and chemotherapy. The median survival time of patients with GBM has remained less than 2 years despite concerted efforts to improve therapy. As a new approach to treat GBM we generated retroviral particles encoding mutant survivin for transduction of glioma cells. We demonstrate here that retroviral overexpression of a nonphosphorylatable Thr-34 --> Ala mutant of survivin (survivinT34A), in the glioma cell lines U373 and H4 resulted in a marked increase in the percentage of cells bearing multiple nuclei, which was accompanied by significantly decreased cell proliferation, and in greater numbers of cells with hypodiploid DNA content. Administration of the broad caspase inhibitor z-Val-Ala-Asp(OMe)-fluoromethyl-ketone did not reduce the cell death rate. Yet increased nuclear translocation of apoptosis-inducing factor (AIF) was observed in cells transduced with survivinT34A, indicating caspase-independent cell death. Transduction of retroviral vectors encoding wild-type survivin also led to the appearance of multinuclear cells. In contrast to mutant survivin, overexpressed wild-type survivin did not increase the cell death rate and no enhanced nuclear AIF translocation was observed. We suggest that retroviral vectors delivering mutant survivinT34A might be employed for the treatment of glioblastoma.

Leiomyomas of the duodenum.

Leiomyoma is a neoplasm of smooth muscle relatively common in the stomach, but very rare in the duodenal location. Symptoms are gastrointestinal bleeding or abdominal pain resembling peptic disease. Three cases of duodenal leiomyomas are described, and the importance of endoscopy is emphasized as a diagnostic tool. Surgical resection of the tumor is the recommended therapeutic procedure, and the difficulty in deciding at the pathological examination whether the leiomyoma is benign or malignant demands prompt follow-up of patients after surgery.

Idiopathic chondrolysis--an immunopathologic study.

Investigations were performed to determine the potential of an immunologically-mediated basis underlying development of severe bilateral knee chondrolysis arising over a 2-yr period in a 29-yr-old man. Humoral and cell-mediated immune responses to autologous and homologous articular cartilage proteoglycan and collagen rich fractions were identified in sequential studies. Employing gradient derived peripheral blood mononuclear cells there was demonstration of spontaneous, T cell mitogen augmented and autologous cartilage antigen-induced release of factors capable of degrading articular cartilage proteoglycans and inhibiting chondrocyte glycosaminoglycan synthesis. Evidence has thus been provided incriminating immunologic events, likely functioning in a perpetuant manner, in the pathogenesis of this chondrolytic process.

Split-thickness skin graft for treatment of oral benign mucous membrane pemphigoid. Report of a case.

The painful oral lesions of benign mucous membrane pemphigoid often make the wearing of complete dentures difficult or impossible. A mandibular split-thickness skin graft vestibuloplasty was performed on a patient with benign mucous membrane pemphigoid. This procedure may be indicated in those cases which do not respond to meticulous denture construction and steroid therapy.

Acquired circulating anticoagulant to factor VIII. Response to high doses of cryoprecipitate and immunosuppressive therapy.

Hematuria, arthralgias, and bleeding from subcutaneous and soft tissues developed in a 56-year-old man with an allergic background following a course of sulfisoxazole for urinary tract infection, Coagulation studies demonstrated the presence of an inhibitor to factor VIII in high titers. Massive doses of antihemophilic factor concentrate (30,000 to 60,000 units/day), azathioprine, and corticosteroids were followed by an immediate decrease in bleeding and a reduced level of inhibitor units. Three months after the onset of symptoms, the partial thromboplastin time returned to normal and inhibitor units to factor VIII became undetectable.