Micromarrows--three-dimensional coculture of hematopoietic stem cells and mesenchymal stromal cells

Hematopoietic stem cell (HSC) transplant is a well established curative therapy for some hematological malignancies. However, achieving adequate supply of HSC from some donor tissues can limit both its application and ultimate efficacy. The theory that this limitation could be overcome by expanding the HSC population before transplantation has motivated numerous laboratories to develop ex vivo expansion processes. Pioneering work in this field utilized stromal cells as support cells in cocultures with HSC to mimic the HSC niche. We hypothesized that through translation of this classic coculture system to a three-dimensional (3D) structure we could better replicate the niche environment and in turn enhance HSC expansion. Herein we describe a novel high-throughput 3D coculture system where murine-derived HSC can be cocultured with mesenchymal stem/stromal cells (MSC) in 3D microaggregates--which we term "micromarrows." Micromarrows were formed using surface modified microwells and their ability to support HSC expansion was compared to classic two-dimensional (2D) cocultures. While both 2D and 3D systems provide only a modest total cell expansion in the minimally supplemented medium, the micromarrow system supported the expansion of approximately twice as many HSC candidates as the 2D controls. Histology revealed that at day 7, the majority of bound hematopoietic cells reside in the outer layers of the aggregate. Quantitative polymerase chain reaction demonstrates that MSC maintained in 3D aggregates express significantly higher levels of key hematopoietic niche factors relative to their 2D equivalents. Thus, we propose that the micromarrow platform represents a promising first step toward a high-throughput HSC 3D coculture system that may enable in vitro HSC niche recapitulation and subsequent extensive in vitro HSC self-renewal.

Nitric oxide releasing plasma polymer coating with bacteriostatic properties and no cytotoxic side effects

We report a stable plasma polymer coating which releases nitric oxide, inhibiting bacterial growth without cytotoxic side effects.

[Intravascular embolization of intracranial arteriovenous hemangiomas]

The paper presents the technique of the procedures as well as the results of treating patients with operable difficult and non-operable intracranial angiomas.

MATERIAL AND METHOD

During 26 months (1997, 1998 and 1999) 13 patients (7 women and 6 men) with intracranial arteriovenous haemangiomas underwent intravascular embolisation. The angiomas were embolised with coils (COOK) and Histoacryl with Lipiodol.

RESULTS

Among the angioma patients, 2 were treated successfully during four procedures, 2 were treated during 3 procedures. The treatment was fully successful in 6 patients following the 3-rd and 4-th procedures. 5 patients are still being treated. Complications, during both the treatment and follow-up, were observed in two patients.

CONCLUSIONS

The intravascular embolisation of intracranial angiomas is an effective treatment modality. It carries, though, a certain risk of complication development. Using this method in neuro-surgically non-operable cases is a method of choice.

[Problems with therapy for renovascular hypertension in Takayasu's arteritis--on the basis of two cases]

Takayasu's arteritis is non-specific vasculitis, affecting aorta and its main branches. Renal involvement is usually manifested by renovascular hypertension followed by ischemic nephropathy. Early start of immunosuppressive treatment can substantially improve prognosis and delay progress of dangerous organic complications. On the basis of two cases of Takayasu's arteritis with renal involvement, we paid the attention to progressive nature of disease with renovascular hypertension, requiring corrective operation of renal arteries, despite intensive immunosuppressive treatment.

[Intravascular embolization of intracranial aneurysms]

The paper presents indications for and the technique of the intravascular procedures as well as the results of treating patients with intracranial aneurysms.

MATERIAL AND METHOD

Between 1997 and the May 2000, 25 patients (14 women and 11 men) with cerebral aneurysms underwent intravascular embolisation. The aneurysms were embolised with MDS-N BALT with coils. In 5 patients with aneurysm (about 2 cm), the procedure was performed in two or three steps.

RESULTS

Aneurysms were embolised successfully in 19 patients. Three patients revealed intra- and postoperative complication manifestations.

CONCLUSIONS

Intravascular embolisation of intracranial aneurysms is an affective treatment modality. It carries, though, a certain risk of complication development. Using this method in neurosurgically non-operable cases is a method of choice.