Maturation of composite ligament

A variety of synthetic fibrillar ligaments are being developed and clinically investigated. The tissue response to the variety of polymeric fibrils is similar. The soft-tissue response to carbon fiber braid substituting for lateral collateral ligament in three human knees and for the anterior cruciate ligament in one was examined 12-42 months after surgery. An advanced stage of maturity of the composite structure was particularly evident by dense bundles of collagen in one of the collateral ligaments and in the substitute for the anterior cruciate ligament. Associated with the newly formed collagen the carbon fibril initially formed unique carbon collagen of composite structural units. Eventually, subsidence of the fibroblast response was accompanied by an increase in density and width of the collagen fibers and by a loss of the configuration of the carbon-collagen units. Even the mature collagenous structure was not comparable to the natural ligament.     

Frequent ongoing T-cell receptor rearrangements in childhood B- precursor acute lymphoblastic leukemia: implications for monitoring minimal residual disease

Crosslineage T-cell receptor delta (TCR delta) rearrangements are widely used as tumor markers for the follow up of minimal residual disease in childhood B-precursor acute lymphoblastic leukemia (ALL) by polymerase chain reaction (PCR). The major drawback of this approach is the risk of false-negative results due to clonal evolution. We investigated the stability of V delta 2D delta 3 rearrangements in a group of 56 childhood B-precursor ALL patients by PCR and Southern blot analysis. At the PCR level, V delta 2D delta 3-to-J alpha rearranged subclones (one pathway for secondary TCR delta recombination) were demonstrated in 85.2% of V delta 2D delta 3-positive patients tested, which showed that small subclones are present in the large majority of patients despite apparently monoclonal TCR delta Southern blot patterns. Sequence analysis of V delta 2D delta 3J alpha rearrangements showed a biased J alpha gene usage, with HAPO5 and J alpha F in 26 of 32 and 6 of 32 clones, respectively. Comparison of V delta 2D delta 3 rearrangement status between diagnosis and first relapse showed differences in seven of eight patients studied. In contrast, from first relapse onward, no clonal changes were observed in six patients studied. To investigate the occurrence of crosslineage TCR delta rearrangements in normal B and T cells, fluorescence-activated cell sorter-sorted peripheral blood CD19+/CD3- and CD19-/CD3+ cell populations from three healthy donors were analyzed. V delta 2D delta 3 rearrangements were detected at low frequencies in both B and T cells, which suggests that V delta 2-to-D delta 3 joining also occurs during normal B-cell differentiation. A model for crosslineage TCR delta rearrangements in B-precursor ALL is deduced that explains the observed clonal changes between diagnosis and relapse and is compatible with multistep leukemogenesis of B-precursor ALL.     

Deletion of the ferric uptake regulator Fur impairs the in vitro growth and virulence of Actinobacillus pleuropneumoniae

In order to investigate the role of the ferric uptake regulator Fur in the porcine lung pathogen Actinobacillus pleuropneumoniae, we constructed an isogenic in-frame deletion mutant, A. pleuropneumoniae Deltafur. This mutant showed constitutive expression of transferrin-binding proteins, growth deficiencies in vitro, and reduced virulence in an aerosol infection model.     

Xenografting of fetal pig ventral mesencephalon corrects motor asymmetry in the rat model of Parkinson's disease

Summary A suspension of cells from embryonic day 21 fetal pig ventral mesencephalon was transplanted into the striatum of 20 immunosuppressed rats with 6-hydroxydopamine-induced lesions of the nigrostriatal dopamine pathway. Of these rats, 15 showed reduction of amphetamine-induced ipsilateral rotation by 9 weeks and complete reversal of rotation by 14–17 weeks. Animals maintained stable reversal of rotations (contralateral direction) until cessation of Cyclosporin A (CyA) treatment at 15–20 weeks. Within 4–9 weeks after CyA removal, these rats showed exclusively ipsilateral rotations during behavioral testing which were comparable to pre-transplant levels, suggesting that the grafts were rejected upon cessation of CyA treatment. Rats were sacrificed and tyrosine hydroxylase (TH) immunohistochemistry was performed at several time points, both on and off CyA, to examine a possible correlation between the degree of rotational behavior and the number of TH- positive surviving grafted cells. Staining showed large numbers (230–12,329) of TH-positive surviving cells in animals displaying a high degree of rotational correction (1.6 to -9.6 net ipsilateral rotations/min) after cessation of CyA treatment. Two control groups, those transplanted with nonneuronal cells from the pig ventral mesencephalon (n=5) and those receiving only daily CyA injections (n=4) showed no significant reduction of net ipsilateral rotations throughout the experiment. No TH-positive surviving cells were seen in the one non-neuronal transplant analyzed. This data demonstrates long-term retention of xenografted tissue with immunosuppression and its concomitant restoration of normal motor behavior in the rat model of Parkinson's disease.     

Births of normal daughters after MicroSort sperm separation and intrauterine insemination, in-vitro fertilization, or intracytoplasmic sperm injection

The world's first deliveries of normal babies after use of flow cytometric separated human sperm cells (MicroSort) for preconception gender selection are reported. Offspring were of the desired female gender in 92.9% of the pregnancies. Most of these pregnancies and births were achieved after simple intrauterine insemination.      

Postosteonecrotic osteoarthritis-like disorder of the femoral head of rats

The femoral heads of 15 rats were studied histologically 3 months after the induction of ischaemic necrosis by incising the cervical periosteum and cutting the ligamentum teres. The epiphyses consisted of immature disorganized subchondral and trabecular bone. The inter-trabecular spaces contained fibrous or haematopoietic tissue. Residual necrotic bone was rare. There was marked osteoblastic and osteoclastic activity. The articular aspect of the heads showed a spectrum of changes, ranging from cartilaginous degeneration with fibrillation and loss of glycosaminoglycans to an eburnated and polished bony surface. In seven rats, transphyseal bridges connected the epiphyseal and metaphyseal bony trabeculae to each other. It is suggested that the postnecrotic reparative processes, including the resorption of the necrotic debris and its replacement by newly formed, weak bone, led to an osteoarthritis-like disorder. This healing pattern of the necrotic femoral head was reminiscent of the progressive remodelling that occurs in rings in femoral capital osteonecrosis of adult human patients and in Perthes's disease of children.     

Detecting pre-ovulatory luteinizing hormone surges in urine

The study objectives were to determine (i) if pre-ovulatory luteinizing hormone (LH) surges, undetected in urine by two immunoradiometric assays (IRMA), were detectable by an ultrasensitive immunofluorometric assay (IFMA) and (ii) the influence of creatinine adjustment on the detection and timing of the urinary LH surges. Daily urine specimens were contributed by healthy 25-36 year old volunteers during 14 ovulatory menstrual cycles for an epidemiological study conducted in 1983-1985. Specimens were selected as having been previously assayed by two IRMA without consistently detecting LH surges. These urine specimens were remeasured using an IFMA and adjusted for creatinine concentration. IFMA measurements revealed unambiguous LH surges in all cycles. Adjusting IRMA urinary LH values for creatinine concentrations revealed previously undetected LH surges in four of eight cycles. Creatinine adjustment also altered the timing of IRMA and IFMA LH surges by 1-5 days. These results demonstrate an IFMA that detects pre- ovulatory LH surges in unpreserved, frozen urine from cycles where such surges were previously undetectable. Further, creatinine adjustment can markedly affect detection and timing of the onset and peak of the urinary LH surge. While our analysis suggests that this adjustment improves the validity of the LH measure, this requires further investigation.