Development of a thermosensitive HAMA-containing bio-ink for the fabrication of composite cartilage repair constructs

Fine-tuning of bio-ink composition and material processing parameters is crucial for the development of biomechanically relevant cartilage constructs. This study aims to design and develop cartilage constructs with tunable internal architectures and relevant mechanical properties. More specifically, the potential of methacrylated hyaluronic acid (HAMA) added to thermosensitive hydrogels composed of methacrylated poly[N-(2-hydroxypropyl)methacrylamide mono/dilactate] (pHPMA-lac)/polyethylene glycol (PEG) triblock copolymers, to optimize cartilage-like tissue formation by embedded chondrocytes, and enhance printability was explored. Additionally, co-printing with polycaprolactone (PCL) was performed for mechanical reinforcement. Chondrocyte-laden hydrogels composed of pHPMA-lac-PEG and different concentrations of HAMA (0%-1% w/w) were cultured for 28 d in vitro and subsequently evaluated for the presence of cartilage-like matrix. Young's moduli were determined for hydrogels with the different HAMA concentrations. Additionally, hydrogel/PCL constructs with different internal architectures were co-printed and analyzed for their mechanical properties. The results of this study demonstrated a dose-dependent effect of HAMA concentration on cartilage matrix synthesis by chondrocytes. Glycosaminoglycan (GAG) and collagen type II content increased with intermediate HAMA concentrations (0.25%-0.5%) compared to HAMA-free controls, while a relatively high HAMA concentration (1%) resulted in increased fibrocartilage formation. Young's moduli of generated hydrogel constructs ranged from 14 to 31 kPa and increased with increasing HAMA concentration. The pHPMA-lac-PEG hydrogels with 0.5% HAMA were found to be optimal for cartilage-like tissue formation. Therefore, this hydrogel system was co-printed with PCL to generate porous or solid constructs with different mesh sizes. Young's moduli of these composite constructs were in the range of native cartilage (3.5-4.6 MPa). Interestingly, the co-printing procedure influenced the mechanical properties of the final constructs. These findings are relevant for future bio-ink development, as they demonstrate the importance of selecting proper HAMA concentrations, as well as appropriate print settings and construct designs for optimal cartilage matrix deposition and final mechanical properties of constructs, respectively.

Quantitative PCR detection of t(11;14) bcl-1/JH in mantle cell lymphoma patients: comparison of peripheral blood and bone marrow aspirate samples

OBJECTIVE

Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma (NHL) featured by participation of the lymph nodes, spleen, blood and bone marrow with a short remission period to standard therapies and a median overall survival of 4-5 years.

PATIENTS AND METHODS

In this study, we compare the levels of bcl-1/JH fusion products detected by q-PCR in the concurrent peripheral blood (PB) and bone marrow (BM) aspirate samples from 7 patients with MCL.

RESULTS

In patients with moderate to high levels of bcl-1/JH copies, the results of q-PCR analysis of PB and BM aspirate samples correlate well. In patients with high levels of bcl-1/JH copies, instead, PB levels are a good indication of tumor burden. Finally, in patients with low levels of bcl-1/JH copies, the t(11;14) may be detected by identification of neoplastic cells.

CONCLUSIONS

Our data suggest that PB can be reliably used in place of BM aspirate both for detection of translocation status during minimal residual disease monitoring and for a possible molecular relapse, especially in those patients who have moderate to high levels of bcl-1/JH copies. If these results will be confirmed on a wider number of MCL patients, future study will be required to address the issue.

Temozolomide as salvage treatment in primary brain lymphomas

Methotrexate (MTX)-based chemotherapy extends survival in patients with primary brain lymphomas, but it is not clear whether multiagent chemotherapy is superior to MTX alone. Treatment options for patients with recurrent primary brain lymphoma are limited; there is no standard second-line chemotherapy. New chemotherapeutic agents with clear activity in brain lymphoma are needed for treatment of recurrent disease. We report the results of a phase II trial assessing activity of the alkylating agent temozolomide in immunocompetent patients with recurrent primary brain lymphomas, previously treated with high-dose MTX-containing chemotherapy and/or radiotherapy. A median of two courses (range 1–12) of temozolomide 150 mg m⁻² day⁻¹, for 5 days every 4 weeks was administered to 36 patients yielding nine complete and two partial responses (response rate: 31%; 95% confidence interval 16–46%). One-year survival was 31% (95% confidence interval 16–46%). Toxicity was negligible. We conclude that temozolomide is active in recurrent primary brain lymphomas and should further be evaluated in this disease, perhaps in combination with MTX as initial treatment.

Pure red cell aplasia in Felty's syndrome: a case report of successful reversal after cyclosporin A treatment

We describe the first report of a patient with Felty's syndrome who developed pure red cell aplasia, likely not attributable to medication, that was successfully treated with cyclosporin A.

Low-dose Ara-C in myelodysplastic syndromes and acute nonlymphoid leukemia. Experience with seven patients

Seven patients were treated with low dose Ara-C (LDAC). Five patients had acute nonlymphoid leukemia (ANLL), two patients had myelodisplastic syndrome (MDS): refractory anemia (RA) and refractory anemia with excess of blasts in transformation (RAEB-t). Ara-C treatment was given by s.c. injections at a dose of 10-11 mg/m2 every 12 h and only on two occasions by continuous infusion. No improvement, or limited improvement, was observed in five patients and they died of leukemia or of disease-related complications. Two patients with ANLL achieved remission: the first patient after bone marrow aplasia, the second without aplasia but with morphologic evidence of granulocytic differentiation of leukemic cells.

[Correlation between preincubation time of the leukocyte feeder-layer and in vitro granulocytic-macrophage colony growth]

Granulocytic-macrophage colony in vitro formation depends on the presence of the colony stimulating factor (CSF). When, in double layer agar method, the CSF is provided from leucocyte underlayers, the pre-incubation time of the feeder-layers must be kept constant. The results obtained in this study have demonstrated in fact that the growth of the colonies can be remarkably different if feeder-layers are incubated for 1, 7 or 14 days.