Human mini-chromosomes in mouse embryonal stem cells

We have introduced human mini-chromosomes of 4 Mb and approximately 15 Mb in size into mouse embryonal stem cells. Although these human mini- chromosomes are stable in hamster and chicken cells, they re-arrange or segregate aberrantly in the embryonal stem cells and are rapidly lost in the absence of selection. However, one of the mini-chromosomes re- arranged, acquired mouse centromeric sequences and was then stably maintained for at least 60 population doublings in culture. This mini- chromosome, which is 4 Mb in size, is a candidate for a mouse germ line chromosome vector.      

A translational approach for limb vascular delivery of the micro-dystrophin gene without high volume or high pressure for treatment of Duchenne muscular dystrophy

Background  

Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder with monogenic mutations setting the stage for successful gene therapy treatment. We have completed a study that directly deals with the following key issues that can be directly adapted to a gene therapy clinical trial using rAAV considering the following criteria: 1) A regional vascular delivery approach that will protect the patient from widespread dissemination of virus; 2) an approach to potentially facilitate safe passage of the virus for efficient skeletal muscle transduction; 3) the use of viral doses to accommodate current limitations imposed by vector production methods; 4) and at the same time, achieve a clinically meaningful outcome by transducing multiple muscles in the lower limb to prolong ambulation.     

Zum Ursprung der Normalantikörper

Zusammenfassung In allen Studien mit modernen Methoden der keimfreien Forschung, der Serologie und der Genetik hat sich als die Ursachenachweisbarer normaler Hämagglutinine immunogene Stimulation beweisen oder hochwahrscheinlich machen lassen. Ererbt ist die Fähigkeit, Antikörper zu bilden. Genetische Faktoren dürften bei der Induktion der Antikörpersynthese durch Antigene bedeutungsvoll sein. Auch ist nach dem heutigen Stande des Wissens die primäre Globulinstruktur genetisch bedingt.Die eigenen hier referierten Versuche wurden von der U.S. National Science Foundation durch Grant G-3516 und durch Grant DA 49-007-MD-463 der Research and Development Division, Office of the Surgeon General, Department of the Army, Washington, D.C., unterstützt.Established Investigator of the American Heart Association.     

Mutational analysis of the SOX9 gene in campomelic dysplasia and autosomal sex reversal: lack of genotype/phenotype correlations

It has previously been shown that, in the heterozygous state, mutations in the SOX9 gene cause campomelic dysplasia (CD) and the often associated autosomal XY sex reversal. In 12 CD patients, 10 novel mutations and one recurrent mutation were characterized in one SOX9 allele each, and in one case, no mutation was found. Four missense mutations are all located within the high mobility group (HMG) domain. They either reduce or abolish the DNA-binding ability of the mutant SOX9 proteins. Among the five nonsense and three frameshift mutations identified, two leave the C-terminal transactivation (TA) domain encompassing residues 402-509 of SOX9 partly or almost completely intact. When tested in cell transfection experiments, the recurrent nonsense mutation Y440X, found in two patients who survived for four and more than 9 years, respectively, exhibits some residual transactivation ability. In contrast, a frameshift mutation extending the protein by 70 residues at codon 507, found in a patient who died shortly after birth, showed no transactivation. This is apparently due to instability of the mutant SOX9 protein as demonstrated by Western blotting. Amino acid substitutions and nonsense mutations are found in patients with and without XY sex reversal, indicating that sex reversal in CD is subject to variable penetrance. Finally, none of 18 female patients with XY gonadal dysgenesis (Swyer syndrome) showed an altered SOX9 banding pattern in SSCP assays, providing evidence that SOX9 mutations do not usually result in XY sex reversal without skeletal malformations.      

Monoclonal xenogeneic antibodies to murine cell surface antigens: identification of novel leukocyte differentiation antigens.

Hybrid myeloma cell lines secreting monoclonal antibodies to mouse cell surface antigens have been prepared. Spleen cells from a DA rat immunized with B10 mouse spleen cells that had been enriched for T cells were fused to cells from a nonsecreting mouse myeloma line (NSI). The presence in the culture supernatants of antibodies binding to mouse spleen cells was tested by a binding assay with 125I-labeled anti-rat IgG. From a large number of positive cultures, ten independent hybrid clones were purified, each secreting a different antibody. Each antigenic target was analyzed by (a) gel electrophoresis of immunoprecipitated 125 I-labeled cell surface molecules, (b) heat stability, (c) strain and species distribution and (d) cross-inhibition of binding of different monoclonal antibodies. It was concluded that the ten monoclonal antibodies regognized four types of antigen. One was the heterophile, heat-stable, Forssman antigen. The second (mol.wt. 210 000) appears to be a major 125I-labeled lymphoid cell surface protein. The third, a minor component of spleen cells, was precipitated as two polypeptides of mol.wt. 190 000 and 105 000. Five IgG-secreting clones identify the fourth antigen, a heat-stable, possibly glycolipid component expressed on mouse red blood cells and also on thymocytes. Cross-inhibition studies suggest that these last monoclonal antibodies bind to overlapping, but not identical, determinants. The class and chain composition of the monoclonal antibodies were studied by gel electrophoresis, isoelectric focusing and ability to lyse red blood cells and thymocytes.     

Dynamic and static phantoms for evaluation of digital subtraction angiographic systems

Two types of phantoms were developed with which to evaluate the overall performance of digital subtraction angiography (DSA) systems. A dynamic phantom, called a "fish bone" phantom, consists of polyethylene tubes that simulate blood vessels with various lesions, such as stenoses, ulcers, and aneurysms. With this phantom, washout curves were obtained representing the relationship between iodine content and time. It will be useful for qualitative assessment of DSA images, evaluation of different image-processing schemes, and studies of blood flow analysis. A static phantom, called a "C-D" phantom, can be used for measurement of quantitative contrast-detail (C-D) diagrams and for daily monitoring of DSA systems. This was constructed of tubes of seven different diameters (2.15-0.28 mm) and 14 different concentrations of contrast medium (100%-1.1% Renografin-76 [meglumine and sodium diatrizoate]). The C-D diagrams were determined from an observer performance study using C-D phantom images obtained at four different DSA settings.     

Temperament as a moderator of children's stressful experiences

Data on 158 children, six and nine years old, are analyzed for the relationship between stress and behavior. Undesirable life events and intense "hassles" were particularly correlated with behavioral symptoms. Statistically, temperament appears to moderate this influence but, lacking appreciable variance of symptoms in the models including these interaction effects, the more parsimonious main-effects concept may be more useful.     

The Functional Status of the ACL in Varus OA of the Knee: The Association With Varus Deformity and Coronal Tibiofemoral Subluxation

BackgroundThe present article analyzes the association of the functional anterior cruciate ligament (ACL) status and the overall varus deformity and coronal tibiofemoral subluxation (CTFS) in varus OA of the knee.MethodsOne hundred consecutive knees with varus OA in 84 patients were prospectively included. Knees were divided into two groups, in accordance with the ACL status (functionally sufficient or insufficient). All included patients were potential candidates for unicompartmental knee arthroplasty with predominantly medial compartment OA. Knees with Kellgren/Lawrence ≥ grade 3 in the lateral compartment were excluded leaving 79 knees to be included in this study. Mechanical varus deformity and CTFS were evaluated on AP radiographs and valgus stress radiographs, and compared between the two groups.ResultsKnees with a functionally insufficient ACL had significantly more varus deformity on hip-to-ankle AP standing radiographs (P = .001) and on valgus stress radiographs (P = .017). CTFS on AP standing radiographs was significantly higher (P = .045) in knees with a functionally insufficient ACL. Seventy-three percent (8/11) of the ACL-insufficient knees had a varus deformity of ≥10° and 64% (7/11) of ACL-insufficient knees had CTFS ≥ 6mm. By contrast, only one patient (2%, 1/41) with an insufficient ACL had< 10° varus deformity and a CTFS of < 6mm.ConclusionFunctional ACL insufficiency in osteoarthritic varus knees is associated with greater varus deformity and more advanced CTFS. Seventy-three percent of ACL-insufficient knees had a varus deformity of ≥10° and 64% of ACL-insufficient knees a CTFS of ≥ 6mm. In the work-up for medial unicompartmental knee arthroplasty, functional ACL insufficiency is likely in knees with varus deformity of ≥10° and CTFS of ≥ 6mm.     

Needle biopsy of renal allografts: comparison of two techniques

Two techniques for renal allograft biopsy were retrospectively evaluated to compare relative safety and efficacy. After ultrasound (US) localization of the kidney and biopsy with a hand-held 14-gauge cutting needle, an adequate specimen was obtained in 74 of 77 cases (96%). Major complications occurred in six of these 77 cases (8%). One hundred four biopsies were performed by using a smaller 18-gauge cutting needle with a spring-loaded biopsy "gun" and real-time US guidance. With this newer technique, specimens adequate for diagnosis were obtained in 99 biopsies (95%). There was a single major complication with this technique (1%). The 18-gauge needle with real-time US guidance yields comparably adequate specimens with a lower frequency of complications.     

31P and 23Na NMR spectroscopy of normal and ischemic rat skeletal muscle. Use of a shift reagent in vivo

23Na NMR spectroscopy was used 1, to define the distribution of the shift reagent for cations, triethylenetetraminehexaacetatedysprosium(III), DyTTHA3-, in the living rat; 2, to define the characteristics of the Na resonances reporting intra- and extracellular Na+ in skeletal muscle in vivo; and 3, to calculate the Na+ concentrations in the intra- and extracellular spaces of the gastrocnemius muscle during well-perfused and ischemic conditions. The concentration of DyTTHA3- infused intravenously into the jugular vein of the living rat reached a maximum value of 8-9 mM in the extracellular space of the muscle after ca 40 min of infusion. This allowed excellent discrimination of extra- and intracellular Na signals (Nao and Nai, respectively) and did not spoil the resolution of concurrent 31P NMR spectra. Infusion of shift reagent changed neither hemodynamic performance of the rat nor the high-energy phosphate content of skeletal muscle. Shift reagent enters ca 15% (v/w) of the rat body weight; this corresponds to almost all of the "fast" or rapidly permeable extracellular space. It is excreted from the body with a pseudo-first order rate constant of 0.0158 min-1. In resting muscle, we estimate that [Na+]i is 3-5 mM and, in muscle perfused with the sodium salt of the shift reagent, that [Na+]o in the fast exchangeable extracellular space is 166 mM. During 11 h of ischemia at 37 degrees C, the area of the Nai+ signal area monotonically increased sixfold. Based on estimates for maximum changes in fluid shifts reported by the decrease in the area of the Nao signal area, we calculate that the lower limit for [Na+]i after 11 h of ischemia is 27 mM. The NMR-visibility factors for the extracellular and intracellular Na+ signals are essentially the same. This study demonstrates that the shift reagent DyTTHA3- is acutely non-toxic and that the 23Na NMR spectra obtained can be used to quantitate [Na+]o and [Na+]i in tissues in vivo. Using this technique, we found that the transmembrane sodium gradient fell from ca 35 in well-perfused skeletal muscle to less than 6 during prolonged ischemia.