New bone formation by murine osteoprogenitor cells cultured on corticocancellous allograft bone

The gold standard for bone grafting in orthopedics is autograft, however autograft has a limited supply and is associated with significant morbidity at the harvest site. One alternative, allograft bone, provides an osteoconductive scaffold, is in less limited supply, and it does not require a harvest from the patient. However, allograft lacks both osteogenic cells and osteoinductive proteins that make autograft bone so advantageous. This study provides a model to investigate strategies for augmentation of corticocancellous allograft bone discs with bone marrow‐derived osteoprogenitor cells (OPCs) plus exogenous growth factors in vitro. In this model, allograft bone discs were created by cutting 1‐mm thick slices from the distal femur and proximal tibia of euthanized mice. The allografts were sterilized and scanned by micro‐computed tomography (µCT) to provide the pre‐culture graft volume and trabecular characteristics. The discs were then seeded with OPCs harvested from murine bone marrow. The seeded grafts were placed in organ culture until harvest, after which they were re‐scanned by µCT and the data compared to the corresponding pre‐culture data. In addition, bone morphogenetic protein‐7 (BMP‐7, also know as osteogenic protein‐1 or OP‐1), basic fibroblast growth factor (bFGF), and OP‐1 combined with bFGF were added on a daily basis to the cultures. After final µCT scanning, all grafts were sectioned and evaluated histologically after hematoxylin and eosin (H&E) staining. µCT scans of cultured allografts with cells at 3, 5, and 9 weeks showed a time‐dependent, statistically significant increase in bone volume. The trabecular thickness (Tb.Th.) of grafts, from both groups that were augmented with OP‐1, showed a statistically significant increase in trabecular thickness of allografts with OPCs. These data suggest that bone marrow‐derived OPCs adhere to, and produce, new bone on corticocancellous allograft in vitro. When exogenous OP‐1 is added to this model, an increase in the production of bone onto the corticocancellous allograft bone disc is seen. This model allows for the investigation of the effects of multiple growth factors, and other interventions, on OPCs seeded onto allograft bone in vitro. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res     

Comparison of chromosome analysis to DNA content by flow cytometry for pediatric tumors

Chromosome analyses in a series of 50 pediatric tumor samples showed abnormal chromosome number, ranging from hypodiploid to tetraploid. Aliquots of the same solid tumor samples were analyzed by flow cytometry (FCM). Material from spontaneous abortions and 12 tumor samples with normal chromosomes were also compared in a control series of 83 samples. Tumors or abortuses with 44-48 chromosomes could not be differentiated from material with normal diploid complement by FCM. However, greater than or equal to 3-4 extra chromosomes produced detectable differences in mean DNA index. Triploidy and tetraploidy were readily identified by FCM. It is concluded that FCM could identify an important group of hyperdiploid pediatric tumors, as well as 3N and 4N tumor complements.     

Quantitative evaluation of the penile vascular status by means of the 99mTc-penogram in conjunction with either papaverine or prostaglandin E1 in the anaesthetised baboon model.

The evaluation of both the arterial blood supply and the venous drainage of the penis is essential in the assessment of the impotent male. The vasoactive drugs papaverine and prostaglandin E1, as intracavernous injections, cause penile erections by influencing arterial blood supply and venous drainage. These drugs were used in a baboon model together with a 99mTc-penogram to provide information on the vascular status of the penis. An increase in penile blood pool was observed, more dramatic and rapid after administration of papaverine. A quantitative assessment of the vascular status seems possible and will next be monitored in a vascular-compromised baboon for purposes of clinical application.     

Immunodominant epitopes of the adhesin of Mycoplasma pneumoniae.

Overlapping octapeptides from the amino acid sequence of the adherence protein of Mycoplasma pneumoniae were synthesized and used as the antigen in an enzyme-linked immunosorbent assay with serum samples from M. pneumoniae-infected patients. Of a sequence of 338 amino acids positioned between leucine 801 and leucine 1139, only two regions with immunodominant continuous epitopes were detected. The immunoglobulin G and immunoglobulin M antibodies of child and adult patients reacted especially with the NH2-(810)-W-I-G-N-G-Y-R-Y peptide but also reacted with the NH2-(1124)-F-T-D-F-V-K-P-R peptide.     

Trigeminal neuralgia (tic douloureux): MR imaging assessment

The magnetic resonance (MR) imaging studies and clinical records of 29 patients with typical or atypical trigeminal neuralgia (TN) were retrospectively reviewed and compared with the MR studies of 30 patients imaged for reasons unrelated to the fifth cranial nerve. The symptomatic patients were in three groups. Group 1 included those without masses or multiple sclerosis (MS) and those who had not undergone microvascular decompression; group 2, those who underwent microvascular decompression; and group 3, those with masses or MS. Twenty-seven percent of the control group and 57% of the symptomatic patients without masses or MS showed vessel contact with the root entry zone of the preganglionic segment of the fifth cranial nerve. Vessel contact in the symptomatic groups was generally indistinguishable from that seen in the normal group. Fifteen percent of the patients had MS or masses. It is concluded that MR imaging is useful in evaluating patients with TN by facilitating identification of MS or masses but is not helpful in selecting patients with vascular contact who might benefit from microvascular decompression.     

Pediatric heart transplantation

Since the introduction of cyclosporine in the early 1980s, there has been a surge of activity in the field of pediatric heart transplantation. Careful patient selection has resulted in operative and short-term patient survival comparable to that achieved in adult transplant programs. The results of neonatal heart transplantation have been exciting and encouraging; neonates may require less immunosuppressive therapy than older infants and children. Transplantation clearly offers the chance of survival and significant rehabilitation to children with end-stage heart disease. Long-term management issues include the effects of chronic immunosuppressive therapy on growth and development and renal function, and the time-related risk of rejection, infectious complications, neoplasms, and graft atherosclerosis.     

Comparative biodistribution of methotrexate and monoclonal antibody-methotrexate complexes in mice

The biodistribution of radiolabelled methotrexate and immune complexes of methotrexate and a murine monoclonal anti-methotrexate antibody has been compared in mice. Complexes formed in-vitro with the antibody, but not with control immunoglobulin. The complexes were, characteristically, acid labile. In-vivo, blood levels, organ distribution and whole body catabolism of methotrexate in immune complexes were similar to those of free antibody, and markedly different from those of free drug. These findings suggest the feasibility of prolonging the survival of drugs and altering in-vivo distribution using complexes with monoclonal antibodies.