Exclusion of the alpha 1(II) cartilage collagen gene as the mutant locus in type IA osteogenesis imperfecta.

Using two restriction site polymorphisms within the structural gene coding for human type II collagen we have examined the segregation of this gene in three pedigrees with dominantly inherited osteogenesis imperfecta (Sillence type IA). We have demonstrated that the gene does not segregate with clinical expression of the disease and cannot, therefore, contain the mutation responsible for osteogenesis imperfecta in these families.     

Sequence analysis and comonomer interactions in poly[(4-chlorophenyl methacrylate)-co-(methyl methacrylate)]s

Copolymers of 4-chlorophenyl methacrylate and methyl methacrylate were prepared and investigated by ¹H and ¹³C NMR spectroscopy. The copolymer composition, determined by chlorine analysis, ¹H and ¹³C NMR, was found to be close to the initial composition of the monomer mixture. The sequence analysis was carried out by analyzing the methoxy signals of the ¹H NMR spectra. Six out of ten tactic and compositional triads could be resolved. It was found that the copolymers are predominantly syndiotactic and the compositional and tactic triad populations are given. The aromatic carbon atoms are sensitive towards compositional and tactic sequence effects, which results in a switch of the order of the tactic signals at different aromatic carbon atoms.     

The development of spatial capacity in piloting and dead reckoning by infant rats: use of the huddle as a home base for spatial navigation

Two forms of spatial navigation, piloting using external cues and dead reckoning using self-movement cues, are manifest in the outward and homeward trips of adult rats exploring from a home base. Here, the development of these two forms of spatial behavior are described for rats aged 14-65 days using a new paradigm in which a huddle of pups or an artificial huddle, a small heat pad, served as a home base on an open circular table that the rats could explore. When moving away from both home bases, the travel distance, path complexity, and number of stops of outward trips from the home base increased progressively with age from postnatal day 16 through 22. When returning to the home bases, the return trips to the home base were always more direct and had high travel velocities even though travel distance increased with age for the longest trips. The results are discussed in relation to the ideas that: (1) the pups pilot on the outward portion of their excursion and dead reckon on the homeward portion of their excursion, and (2) the two forms of navigation and associated spatial capacity are interdependent and develop in parallel and in close association with locomotor skill.     

Molecular and biochemical mechanisms ofPasteurella haemolyticaleukotoxin-induced cell death

Pasteurella haemolyticaleukotoxin (LKT) is a member of the RTX family of pore-forming toxins that kill bovine immune cells. Several studies have suggested that RTX toxins kill target cells by the induction of apoptosis. In the present study, BL3 bovine leukaemia cells were exposed to LKT and assessed by molecular and flow cytometric techniques that measure different aspects of apoptotic cell death. The intoxicated cells demonstrated morphological, light scatter and Hoechst 33258 staining characteristics consistent with cells undergoing apoptosis. The cells also exhibited internucleosomal DNA fragmentation and poly (ADP-ribose) polymerase (PARP) cleavage, both indicators of apoptosis. LKT-treated cells bound annexin-V-FITC indicating that phosphatidylserine groups were translocated from the inner to the outer leaflet of the cell membrane. The effect of LKT on cells was dose dependent and inhibitable by incubation with anti-LKT monoclonal antibody. Finally, an early step for induction of apoptosis appears to be the binding of LKT to a β2 integrin since pre-incubating cells with anti-β2 integrin antibodies inhibited LKT-induced apoptosis. This study provides new insights into understanding the pathogenesis of bovine pasteurellosis and could lead to the development of both preventative and therapeutic strategies for disease management.     

Overloaded training increases exercise-induced oxidative stress and damage.

We hypothesized that overloaded training (OT) in triathlon would induce oxidative stress and damage on muscle and DNA. Nine male triathletes and 6 male sedentary subjects participated in this study. Before and after a 4-week OT, triathletes exercised for a duathlon. Blood ratio of reduced vs. oxidized glutathione (GSH/GSSG), plasma thiobarbituric acid reactive substances (TBARS), leukocyte DNA damage, creatine kinase (CK), and CK-MB mass in plasma, erythrocyte superoxide dismutase (SOD) activity, erythrocyte and plasma glutathione peroxidase (GSH-Px) activities, and plasma total antioxidant status (TAS) were measured before and after OT in pre- and postexercise situations. Triathletes were overloaded in response to OT. In rest conditions, OT induced plasma GSH-Px activity increase and plasma TAS decrease (both p < 0.05). In exercise conditions, OT resulted in higher exercise-induced variations of blood GSH/GSSG ratio, TBARS level (both p < 0.05), and CK-MB mass (p < 0.01) in plasma; and decreased TAS response (p < 0.05). OT could compromise the antioxidant defense mechanism with respect to exercise-induced response. The resulting increased exercise-induced oxidative stress and further cellular susceptibility to damage needs more study.     

Histopathological landmarks of hepatocellular carcinoma in Malaysians

A study was conducted at the Department of Pathology, University of Malaya Medical Centre, Kuala Lumpur into the histological type (WHO classification), grade (modified Edmondson and Steiner's grading system), mitotic rate, bile production, hyaline globule and Mallory hyaline formation of 52 cases of hepatocellular carcinoma (HCC) diagnosed during a 13-year period between 1st January 1990 to 31st December 2002. In addition, associated cirrhosis, dysplasia (large liver cell dysplasia: LLCD and small liver cell dysplasia: SLCD) and microvascular permeation were also looked for whenever the situation permitted. The patients' ages ranged from 21-years to 85-years (mean = 58.7 years) with a predilection for males and Chinese. Histologically, majority (73.1%) of the tumours demonstrated a trabecular pattern of growth. The bulk (73%) of the tumours were either of grade II or III differentiation. Mitotic activity ranged between 0-100/10 high power fields (hpf) with a mean of 22.2/10 hpf. Bile was noted in 25%, hyaline globules 17.3% and Mallory bodies in one case. Concomitant cirrhosis was present in 73.5%. 73.5% of the cases had associated LLCD. 5 with LLCD also showed SLCD. Microvascular permeation was shown in 76.2% of cases. On comparison with findings from other studies, no major difference seems to exist between the histological characteristics of our HCC cases and that of other populations.     

Discrimination of single-copy IS6110 DNA fingerprints of Mycobacterium tuberculosis isolates by high-resolution minisatellite-based typing

Seven isoniazid-resistant isolates with mutations in the NADH dehydrogenase (ndh) gene were molecularly typed by IS6110-based restriction fragment length polymorphism analysis. All seven isolates with the R268H mutation had identical 1.4-kb IS6110 fingerprints. High-resolution minisatellite-based typing discriminated five of these isolates; two isolates were identical.     

Drosophila dSAP18 is a nuclear protein that associates with chromosomes and the nuclear matrix, and interacts with pinin, a protein factor involved in RNA splicing

SAP18 is a highly conserved protein that was proposed to be involved in multiple cellular processes from autophagy to gene regulation and mRNA processing. In this paper we show that, in Drosophila, dSAP18 is a predominantly nuclear protein that associates to both chromosomes and the nuclear matrix. dSAP18 becomes nuclear early during development, at the onset of cellularization, and remains so all through embryo development. dSAP18 is also nuclear in salivary glands, ovaries and cultured S2 cells. Here we also show that dSAP18 forms a complex with the Drosophila homolog of pinin (dPnn), a protein factor involved in mRNA splicing. dSAP18-dPnn interaction was confirmed in vivo, through co-immunoprecipitation experiments, as well as in vitro, through GST pull-down assays. These results are discussed in the context of the possible functions played by SAP18.     

Effect of denervation on the endogenous phosphorylating activity in the cytosol of rat skeletal muscle

An endogenous phosphorylating activity is demonstrated in the cytosol from soleus muscle of the rat which is markedly stimulated after severing the motor nerve fibers to this muscle. The [γ-³²P]ATP phosphotransferase reaction is heat-labile, dependent upon Mg²⁺ but not Ca²⁺ or cyclic GMP, inhibited by a cyclic AMP dependent protein kinase inhibitor, and directly related to the amount of cytosolic protein which provides the endogenous source of both the protein kinase enzyme, ATP, cyclic AMP and phosphorylatable protein substrate. The time-course of the delayed transitory stimulation of the cytosolic phosphorylating activity of the denervated soleus may involve neurotropic factors.