Disability in patients with chronic patellofemoral pain syndrome: a randomised controlled trial of VMO selective training versus general quadriceps strengthening

This study was a prospective single blind randomised controlled trial to compare the effects of rehabilitation with emphasis on retraining the vastus medialis (VMO) component of the quadriceps femoris muscle and rehabilitation with emphasis on general strengthening of the quadriceps femoris muscles on pain, function and Quality of Life in patients with patellofemoral pain syndrome (PFPS). Patients with PFPS (n=69) were recruited from a hospital orthopaedic clinic and randomised into three groups: (1) physiotherapy with emphasis on selectively retraining the VMO (Selective); (2) physiotherapy with emphasis on general strengthening of the quadriceps femoris muscles (General); and (3) a no-treatment control group (Control). The three groups were then compared before and after an eight-week rehabilitation period. The Selective and General groups demonstrated statistically significant and 'moderate' to 'large' effect size reductions in pain when compared to the Control group. Both the Selective and General groups displayed statistically significant and 'moderate' and 'large' effect size improvements in subjective function and Quality of Life compared to the Control group. Knee flexion excursion during the stance phase of gait, demonstrated that there were no statistical significant differences and only 'trivial' to 'small' effect size differences between the Selective or General groups and the Control group. A large number of PFPS patients can experience significant improvements in pain, function and Quality of Life, at least in the short term, with quadriceps femoris rehabilitation, with or without emphasis on selective activation of the VMO component. Both approaches would seem acceptable for rehabilitating patients with PFPS. It may be appropriate to undertake exercises involving selective activation of the vastus medialis early in the rehabilitation process, however, clinicians should not overly focus on selective activation before progressing rehabilitation, especially in more chronic cases with significant participation restrictions.

Investigation of infection with Campylobacter jejuni in a man with hypogammaglobulinaemia using PCR-single-stranded conformational polymorphism (PCR-SSCP) typing

This study investigated several episodes of infection of Campylobacter jejuni in an immunocompromised male with hypogammaglobulinaemia, presenting with diarrhoea and bacteraemia over a 16-month period, by employing three phenotyping and four genotyping schemes, including the single-stranded conformational polymorphism (SSCP) technique to establish if infection was reinfection or persistent infection. Four isolates from blood culture and two faecal isolates of Campylobacter jejuni were obtained from the patient by direct selective plating on Skirrow Selective agar. Isolates were characterised at the sub-species level by Penner serology, Preston biotyping, Preston phage-typing, as well as E3CJC2 restriction fragment length polymorphism (RFLP), 16S ribotyping, flagellin (flaA) RFLP and single-stranded conformational polymorphism (SSCP) analyses. Phenotyping and genotyping sub-species analyses demonstrated that the patient was infected with at least two different strains of Campylobacter jejuni, i. e. one strain that persisted throughout the 16-month period and another strain that was transient suggesting reinfection from a different source. SSCP analysis was the most discriminatory of all the typing schemes examined and demonstrated an altered genotype of the persistent strain, whereby there were subtle modifications to the hypervariable regions of the flaA gene. Overall, as SSCP examines the hypervariable region of the flaA gene and as this technique can detect point mutations, differences between SSCP banding patterns may represent markers and thus examine mutations that occur under immune selection, thereby permitting the C. jejuni to evade the host immune response. In conclusion, this study describes the novel use of SSCP genotyping of C. jejuni and demonstrated that this method is a highly discriminatory technique which may be beneficial in outbreak characterisation, but which is not suitable to examine the clonal patterns of C. jejuni over a long period of time.

Ethics and economics

The author suggests that one way to better manage the burgeoning costs in acute care settings and improve patient care is by the earlier use of ethics case consultations and end-of-life support from ethics teams. This study determined that, in several very diverse clinical scenarios, timely facilitation of meaningful communication and decision making between patients, families, and health care providers can result in the more appropriate use of health care resources. While few of the patients in this study had recorded advanced directives in place, and there was initially a lack of family consensus in some cases, compliance with the ethics team recommendations led to a more appropriate clinical unit placement; and improved family support helped manage the costs of care and focus on the patients' quality of life. The decrease in the use of medical interventions and therapies after ethics consultations was consistent in all cases presented here.

No association of the dopamine DRD4 receptor (DRD4) gene polymorphism with attention deficit hyperactivity disorder (ADHD) in the Irish population

Attention deficit hyperactivity disorder (ADHD) is one of the most prevalent childhood-onset syndromes affecting 3%-6% of school-age children worldwide. Although the biological basis of ADHD is unknown, a dopaminergic abnormality has long been suggested. The dopamine D4 receptor gene (DRD4) has been mapped to chromosome 11p15.5 and has been implicated in predisposition to ADHD. Several independent genetic association studies have demonstrated increased frequency of the DRD4 7-repeat allele in ADHD cases compared with controls or excess transmission of the 7-repeat allele from parents to affected offspring. However, there have also been few negative studies. In this study we investigated 78 ADHD parent proband trios and 21 parent proband pairs for the transmission of the DRD4 alleles in HHRR and case control design. We found no significant differences in the frequency of the DRD4 alleles transmitted or not transmitted to ADHD cases from their parents nor when comparing case allele frequencies to ethnically matched controls. Therefore, it is unlikely that the DRD4 7-repeat allele is associated with ADHD in the Irish population.

No association between catechol-O-methyltransferase (COMT) gene polymorphism and attention deficit hyperactivity disorder (ADHD) in an Irish sample

Pharmacological and biochemical studies have indicated that imbalances in dopaminergic transmission may contribute to the aetiology of attention deficit hyperactivity disorder (ADHD). The enzyme catechol-O-methyltransferase (COMT) plays a key role in the degradation of catecholamines such as dopamine, L-DOPA, adrenaline, and noradrenaline and therefore could be considered as a candidate locus for ADHD susceptibility. We hypothesised that a proportion of the genetic susceptibility to ADHD may be a consequence of dopamine depletion in the synapses due to high-level activity of the COMT gene (allele 1). Using the haplotype-based haplotype relative risk method and 94 affected children and their parents genotyped for COMT alleles, we found no significant differences in the frequency of the transmitted and nontransmitted alleles to ADHD cases from their parents. The absence of association between COMT alleles and ADHD indicated that this locus does not play a significant role or at least a role independent of other genes, in predisposing to ADHD in the Irish population.

Immuno- and genetic therapy in autoimmune diseases

Animal models of autoimmune disease have been developed that mimic some aspects of the pathophysiology of human disease. These models have increased our understanding of possible mechanisms of pathogenesis at the molecular and cellular level and have been important in the testing, development and validation of new immunotherapies. The susceptibility to develop disease in the majority of these models is polygenic as is the case in humans. The exceptions to this rule are gene knock outs and transgenic models of particular genes which, in particular genetic backgrounds, have also contributed to the understanding of single gene function and their possible contribution to pathogenesis. Gene therapy approaches that target immune functions are being developed with encouraging results, despite the polygenic nature of these diseases. Basically this novel immuno-genetic therapy harnesses the knowledge of immunology with the myriad of biotechnological breakthroughs in vector design and delivery. Autoimmune disease is the result of genetic dysregulation which could be controlled by gene therapy. Here we summarize the genetic basis of these human diseases as well as some of the best characterized murine models. We discuss the strategies for their treatment using immuno- and gene therapy.

Uracil-DNA glycosylase (UNG)-deficient mice reveal a primary role of the enzyme during DNA replication

Gene-targeted knockout mice have been generated lacking the major uracil-DNA glycosylase, UNG. In contrast to ung- mutants of bacteria and yeast, such mice do not exhibit a greatly increased spontaneous mutation frequency. However, there is only slow removal of uracil from misincorporated dUMP in isolated ung-/- nuclei and an elevated steady-state level of uracil in DNA in dividing ung-/- cells. A backup uracil-excising activity in tissue extracts from ung null mice, with properties indistinguishable from the mammalian SMUG1 DNA glycosylase, may account for the repair of premutagenic U:G mispairs resulting from cytosine deamination in vivo. The nuclear UNG protein has apparently evolved a specialized role in mammalian cells counteracting U:A base pairs formed by use of dUTP during DNA synthesis.

Accumulation of premutagenic DNA lesions in mice defective in removal of oxidative base damage

DNA damage generated by oxidant byproducts of cellular metabolism has been proposed as a key factor in cancer and aging. Oxygen free radicals cause predominantly base damage in DNA, and the most frequent mutagenic base lesion is 7,8-dihydro-8-oxoguanine (8-oxoG). This altered base can pair with A as well as C residues, leading to a greatly increased frequency of spontaneous G.C-->T.A transversion mutations in repair-deficient bacterial and yeast cells. Eukaryotic cells use a specific DNA glycosylase, the product of the OGG1 gene, to excise 8-oxoG from DNA. To assess the role of the mammalian enzyme in repair of DNA damage and prevention of carcinogenesis, we have generated homozygous ogg1(-/-) null mice. These animals are viable but accumulate abnormal levels of 8-oxoG in their genomes. Despite this increase in potentially miscoding DNA lesions, OGG1-deficient mice exhibit only a moderately, but significantly, elevated spontaneous mutation rate in nonproliferative tissues, do not develop malignancies, and show no marked pathological changes. Extracts of ogg1 null mouse tissues cannot excise the damaged base, but there is significant slow removal in vivo from proliferating cells. These findings suggest that in the absence of the DNA glycosylase, and in apparent contrast to bacterial and yeast cells, an alternative repair pathway functions to minimize the effects of an increased load of 8-oxoG in the genome and maintain a low endogenous mutation frequency.

Molecular characterization of a human DNA kinase

Human polydeoxyribonucleotide kinase is an enzyme that has the capacity to phosphorylate DNA at 5'-hydroxyl termini and dephosphorylate 3'-phosphate termini and, therefore, can be considered a putative DNA repair enzyme. The enzyme was purified from HeLa cells. Amino acid sequence was obtained for several tryptic fragments by mass spectrometry. The sequences were matched through the dbEST data base with an incomplete human cDNA clone, which was used as a probe to retrieve the 5'-end of the cDNA sequence from a separate cDNA library. The complete cDNA, which codes for a 521-amino acid protein (57.1 kDa), was expressed in Escherichia coli, and the recombinant protein was shown to possess the kinase and phosphatase activities. Comparison with other sequenced proteins identified a P-loop motif, indicative of an ATP-binding domain, and a second motif associated with several different phosphatases. There is reasonable sequence similarity to putative open reading frames in the genomes of Caenorhabditis elegans and Schizosaccharomyces pombe, but similarity to bacteriophage T4 polynucleotide kinase is limited to the kinase and phosphatase domains noted above. Northern hybridization revealed a major transcript of approximately 2.3 kilobases and a minor transcript of approximately 7 kilobases. Pancreas, heart, and kidney appear to have higher levels of mRNA than brain, lung, or liver. Confocal microscopy of human A549 cells indicated that the kinase resides predominantly in the nucleus. The gene encoding the enzyme was mapped to chromosome band 19q13.4.

Mapping susceptibility loci in attention deficit hyperactivity disorder: preferential transmission of parental alleles at DAT1, DBH and DRD5 to affected children

Attention deficit hyperactivity disorder (ADHD) is a common disorder of childhood characterized by inattention, excessive motor activity, impulsivity, and distractibility. It is associated with serious disability in children, adolescents and adults. The etiology of the disorder is unknown, but it has a strong genetic component. Pharmacological and biochemical studies have suggested that dopaminergic and noradrenergic systems are involved. Using a sample of affected children and their parents we have found preferential transmission of alleles at polymorphisms at the dopamine transporter (DAT1), RR=1.2 (1.05-1.37), P=0.006, re-confirming and extending our previous findings for DAT1 (new sample one-tailed P=0.039); dopamine-beta-hydroxylase (DBH), RR=1.31 (1.09-1.56), P=0.0027; and the dopamine D5 receptor (DRD5), RR=1.67 (1.29-2.15), P=0.00005. Transmission of the 'associated' alleles at DAT1 and DBH is stronger in familial cases, RR(DAT1)=1.29 (1.04-1.59), RR(DBH)=1.49 (1.10-2.00), but for DRD5, transmission is stronger in non-familial cases, RR=1.59 (1.05-2.42). TDT analysis of complete trios supports the HHRR analysis, with P<0.05, for DAT1 P<0.005 and DBH and P<0.01 for DRD5. Attributable fractions for DAT1, DBH and DRD5 are calculated at 0.08, 0.12 and 0.20 respectively.

The murine p75 TNF receptor promoter region: DNA sequence and characterization of a cis-acting silencer

The promoter region of the murine p75 TNF receptor (TNF-R) was isolated from a mouse genomic DNA cosmid library. The promoter region is devoid of TATA box and has the characteristics of a house keeping gene since it contains multiple SP1 binding sites. Its mRNA has different initiation sites in different lymphoid cell lines. This promoter confers transcriptional activity to heterologous reporter genes. Deletion analysis showed that there is a silencer element located upstream from position -841. This inhibitory sequence is active both in fibroblasts and T-cell lines transiently or permanently transfected. A fragment from -929 to -841 is capable of transferring this 'silencer' activity to the early SV40 promoter. This activity could be blocked in trans- when a plasmid containing the same sequence was co-transfected with the reporter plasmid indicating that a protein binds to this region of the promoter.

Surveys of Arboreal and Terrestrial Mammals in The Montane Forests of Queanbeyan, New South Wales

Surveys of arboreal and terrestrial mammals were conducted across four State Forests in south-east New South Wales encompassing 80 000 ha. Methods used included spotlighting, Elliott trapping, pitfall trapping, hair-tubing and predator scat analysis. The survey included a plot-based approach and the targeting of areas containing the potential habitat of endangered species. Seven species of arboreal marsupial were detected during spotlighting. The greater glider (Petauroides volans) was significantly more abundant in moist forest compared to dry forest. Its density in moist forest was twice as high in unlogged compared to logged forest and is equivalent to the highest recorded in any forest in NSW. Other arboreal species were less abundant. The yellow-bellied glider (Petaurus australis), which is Threatened in NSW, was detected at only two sites despite the occurrence of suitable habitat throughout the study area. Eight species of native terrestrial mammals were detected. The tiger quoll (Dasyurus maculatus), which is Threatened in NSW, appears to be more common in the southern part of the study area adjoining large areas of National Park, than in other State Forests of south-east NSW. Continued analysis of predator scats is required to determine whether several other species of Threatened terrestrial mammal occur in these forests.

A newly identified DNA ligase of Saccharomyces cerevisiae involved in RAD52-independent repair of DNA double-strand breaks

Eukaryotic DNA ligases are ATP-dependent DNA strand-joining enzymes that participate in DNA replication, repair, and recombination. Whereas mammalian cells contain several different DNA ligases, encoded by at least three distinct genes, only one DNA ligase has been detected previously in either budding yeast or fission yeast. Here, we describe a newly identified nonessential Saccharomyces cerevisiae gene that encodes a DNA ligase distinct from the CDC9 gene product. This DNA ligase shares significant amino acid sequence homology with human DNA ligase IV; accordingly, we designate the yeast gene LIG4. Recombinant LIG4 protein forms a covalent enzyme-AMP complex and can join a DNA single-strand break in a DNA/RNA hybrid duplex, the preferred substrate in vitro. Disruption of the LIG4 gene causes only marginally increased cellular sensitivity to several DNA damaging agents, and does not further sensitize cdc9 or rad52 mutant cells. In contrast, lig4 mutant cells have a 1000-fold reduced capacity for correct recircularization of linearized plasmids by illegitimate end-joining after transformation. Moreover, homozygous lig4 mutant diploids sporulate less efficiently than isogenic wild-type cells, and show retarded progression through meiotic prophase I. Spore viability is normal, but lig4 mutants appear to produce a higher proportion of tetrads with only three viable spores. The mutant phenotypes are consistent with functions of LIG4 in an illegitimate DNA end-joining pathway and ensuring efficient meiosis.

Confirmation of association between attention deficit hyperactivity disorder and a dopamine transporter polymorphism

Attention deficit hyperactivity disorder (ADHD) is a common condition of childhood the symptoms of which include inattention, excessive motor activity, inpulsivity and distractibility. It is strongly familial and twin and adoption studies suggest that the familiality is due, at least in part, to shared genes. Gillis et al found concordance rates in ADHD for MZ and DZ twins of 81% and 29% respectively. Stimulant drugs (eg, methylphenidate) are effective in the treatment of ADHD and inhibit the dopamine transporter. This has led to the development of a hypodopaminergic hypothesis for the disease. Cook et al examined a 3' variable number of tandem repeat (VNTR) polymorphism at the dopamine transporter gene (DAT1) in a sample of 49 ADHD patients and their parents, using the haplotype relative risk (HRR) method. They found a significant association (chi 2 = 7.29, 1 d.f., P = 0.007) between ADHD and the 480-bp DAT1 VNTR allele. The authors stressed the importance of independent replication and we have achieved this in a study of 40 probands and their parents, using the same robust HRR method. As in the study of Cook et al we found that the 480-bp allele was preferentially transmitted to ADHD probands (chi 2 = 6.07, 1 d.f., P = 0.014).

Assessing the Impacts of Logging on Reptiles and Frogs in the Montane Forests of Southern New South Wales

This study describes an assessment of the medium-term effects of selection logging on the reptiles and frogs in the montane forests near Queanbeyan, New South Wales. A total of 15 reptile and two frog species was detected across 20 fixed-area plots that were selected according to broad forest type and logging history. Reptile species richness was not significantly different among the different habitat treatments. Total reptile abundance was significantly higher on logged plots, but was not influenced by forest moisture type. Individual analyses for five lizard species (accounting for 84% of all data) showed that several species (Eulamprus tympanum, E. heatwolei and Pseudemoia spenceri) had significantly greater abundances on the logged plots than on the unlogged plots, while two species (Nannoscincus maccoyi and Niveoscincus coventryi) did not differ significantly in their abundances across treatments. Thus, none of these species (which included arboreal, terrestrial and fossorial species) appeared to be adversely affected by past logging practices. Insufficient data on frogs were obtained for analysis. An additional 26 species (13 reptile and 13 frog species) were recorded during a regional survey involving 57 sites. Only two frog species were detected at more than 10 sites, illustrating the difficulty in obtaining data to determine whether logging has any impact on frog populations. Snakes are similarly difficult to assess: 13 snakes from six species were detected in this study. It is concluded that (i) the most abundant reptile species were not adversely affected by past logging, and (ii) many species of herpetofauna were patchy in their distribution across the study area, preventing resolution of the influence of habitat type or disturbance. The difficulty in collecting quantitative data on frogs and snakes confirms the importance of surveys that target endangered frog and snake species so that protective buffer zones can be delineated. Further research is required on these groups to assess the impact of forest management practices.

Release of 5'-terminal deoxyribose-phosphate residues from incised abasic sites in DNA by the Escherichia coli RecJ protein

Excision of deoxyribose-phosphate residues from enzymatically incised abasic sites in double-stranded DNA is required prior to gap-filling and ligation during DNA base excision-repair, and a candidate deoxyribophosphodiesterase (dRpase) activity has been identified in E. coli. This activity is shown here to be a function of the E. coli RecJ protein, previously described as a 5'-->3' single-strand specific DNA exonuclease involved in a recombination pathway and in mismatch repair. Highly purified preparations of dRpase contained 5'-->3' exonuclease activity for single-stranded DNA, and homogeneous RecJ protein purified from an overproducer strain had both 5'-->3' exonuclease and dRpase activity. Moreover, E. coli recJ strains were deficient in dRpase activity. The hydrolytic dRpase function of the RecJ protein requires Mg2+; in contrast, the activity of E. coli Fpg protein, that promotes the liberation of 5'-->3'Rp residues from DNA by beta-elimination, is suppressed by Mg2+. Several other E. coli nucleases, including exonucleases I, III, V, and VII, endonucleases I, III and IV and the 5'-->3' exonuclease function of DNA polymerase I, are unable to act as a dRpase. Nevertheless, E. coli fpg recJ double mutants retain capacity to repair abasic sites in DNA, indicating the presence of a back-up excision function.

Aberrant DNA repair and DNA replication due to an inherited enzymatic defect in human DNA ligase I

Two missense mutations in different alleles of the DNA ligase I gene have been described in a patient (46BR) with immunodeficiencies and cellular hypersensitivity to DNA-damaging agents. One of the mutant alleles produces an inactive protein, while the other encodes an enzyme with some residual activity. A subline of identical phenotype that is homozygous (or hemizygous) for the mutant allele encoding this partially active enzyme has facilitated characterization of the enzymatic defect in 46BR. This subline retains only 3 to 5% of normal DNA ligase I activity. The intermediates in the ligation reaction, DNA ligase I-AMP and nicked DNA-AMP, accumulate in vitro and in vivo. The defect of the 46BR enzyme lies primarily in conversion of nicked DNA-AMP into the final ligated DNA product. Assays of DNA repair in 46BR cell extracts and of DNA replication in permeabilized cells have clarified functional roles of DNA ligase I. The initial rate of ligation of Okazaki fragments during DNA replication is apparently normal in 46BR cells, but 25 to 30% of the fragments remain in low-molecular-weight form for prolonged times. DNA base excision repair by 46BR cell extracts shows a delay in ligation and an anomalously long repair patch size that is reduced upon addition of purified normal DNA ligase I.

Three distinct DNA ligases in mammalian cells

The major DNA ligase of proliferating mammalian cells, DNA ligase I, catalyzes the joining of single strand breaks in double stranded DNA and is active on a synthetic substrate of oligo(dT) hybridized to poly(dA). DNA ligase I does not catalyze the joining of an oligo(dT).poly(rA) substrate. Two additional DNA ligases, II and III, which can act on the latter substrate have been purified from calf thymus. DNA ligase II, which has been described previously, is a 72-kDa protein. DNA ligase III migrates as a 100-kDa protein in denaturing gel electrophoresis. Structural, immunochemical, and catalytic studies on the three DNA ligase activities strongly indicate that they are the products of three different genes.

Mammalian DNA ligases. Catalytic domain and size of DNA ligase I

DNA ligase I is the major DNA ligase activity in proliferating mammalian cells. The protein has been purified to apparent homogeneity from calf thymus. It has a monomeric structure and a blocked N-terminal residue. DNA ligase I is a 125-kDa polypeptide as estimated by sodium dodecyl sulfate-gel electrophoresis and by gel chromatography under denaturing conditions, whereas hydrodynamic measurements indicate that the enzyme is an asymmetric 98-kDa protein. Immunoblotting with rabbit polyclonal antibodies to the enzyme revealed a single polypeptide of 125 kDa in freshly prepared crude cell extracts of calf thymus. Limited digestion of the purified DNA ligase I with several reagent proteolytic enzymes generated a relatively protease-resistant 85-kDa fragment. This domain retained full catalytic activity. Similar results were obtained with partially purified human DNA ligase I. The active large fragment represents the C-terminal part of the intact protein, and contains an epitope conserved between mammalian DNA ligase I and yeast and vaccinia virus DNA ligases. The function of the N-terminal region of DNA ligase I is unknown.