Topo IIIalpha and BLM act within the Fanconi anemia pathway in response to DNA-crosslinking agents.

The Bloom protein (BLM) and Topoisomerase IIIalpha are found in association with proteins of the Fanconi anemia (FA) pathway, a disorder manifesting increased cellular sensitivity to DNA crosslinking agents. In order to determine if the association reflects a functional interaction for the maintenance of genome stability, we have analyzed the effects of siRNA-mediated depletion of the proteins in human cells. Depletion of Topoisomerase IIIalpha or BLM leads to increased radial formation, as is seen in FA. BLM and Topoisomerase IIIalpha are epistatic to the FA pathway for suppression of radial formation in response to DNA interstrand crosslinks since depletion of either of them in FA cells does not increase radial formation. Depletion of Topoisomerase IIIalpha or BLM also causes an increase in sister chromatid exchanges, as is seen in Bloom syndrome cells. Human Fanconi anemia cells, however, do not demonstrate increased sister chromatid exchanges, separating this response from radial formation. Primary cell lines from mice defective in both Blm and Fancd2 have the same interstrand crosslink-induced genome instability as cells from mice deficient in the Fancd2 protein alone. These observations demonstrate that the association of BLM and Topoisomerase IIIalpha with Fanconi proteins is a functional one, delineating a BLM-Topoisomerase IIIalpha-Fanconi pathway that is critical for suppression of chromosome radial formation.

Loss of homologous recombination or non-homologous end-joining leads to radial formation following DNA interstrand crosslink damage.

High levels of interstrand cross-link damage in mammalian cells cause chromatid breaks and radial formations recognizable by cytogenetic examination. The mechanism of radial formation observed following DNA damage has yet to be determined. Due to recent findings linking homologous recombination and non-homologous end-joining to the action of the Fanconi anemia pathway, we speculated that radials might be the result of defects in either of the pathways of DNA repair. To test this hypothesis, we have investigated the role of homologous recombination proteins RAD51 and RAD52, non-homologous end-joining proteins Ku70 and LIG4, and protein MRE11 in radial formation and cell survival following interstrand crosslink damage with mitomycin C. For the studies we used small inhibitory RNA to deplete the proteins from cells, allowing for evaluation of radial formation and cell survival. In transformed normal human fibroblasts, depletion of these proteins increased interstrand crosslink sensitivity as manifested by decreased cell survival and increased radial formation. These results demonstrate that inactivation of proteins from either of the two separate DNA repair pathways increases cellular sensitivity to interstrand crosslinks, indicating each pathway plays a role in the normal response to interstrand crosslink damage. We can also conclude that homologous recombination or non-homologous end-joining are not required for radial formation, since radials occur with depletion of these pathways.

The role of A-kinase anchoring proteins (AKaps) in regulating sperm function.

Cyclic AMP (cAMP)-dependent protein kinase (PKA) is a signalling molecule involved in the regulation of many physiological functions including those of cilia and flagella. PKA localizes to specific cellular structures and organelles by binding to AKAP (A-kinase anchoring protein) molecules via interaction with the regulatory subunits (RI and RII) of PKA. AKAPs are capable of forming multi-protein complexes to coordinate the action of several signalling molecules all at a single location. AKAPs also bind to a group of four proteins that share the RII dimerization/docking (R2D2) domain. R2D2 proteins are expressed at high levels in both the testis and spermatozoa and mutants lacking R2D2 proteins exhibit abnormal sperm motility. Thus AKAPs and AKAP associated proteins appear to be key molecules in the biochemical machinery regulating the functions of flagella and cilia.

Finite-time collapse of N classical fields described by coupled nonlinear Schrödinger equations.

We prove the finite-time collapse of a system of N classical fields, which are described by N coupled nonlinear Schrödinger equations. We derive the conditions under which all of the fields experiences this finite-time collapse. Finally, for two-dimensional systems, we derive constraints on the number of particles associated with each field that are necessary to prevent collapse.

Conical refraction and nonlinearity.

We study conical refraction in crystals where both diffraction and nonlinearity are present. We develop a new set of evolution equations. We find that nonlinearity induces a modulational instability when it is defocussing as well as focussing. We also examine the evolution of incident beams which contain analytic singularities, and in particular optical vortices, which do not feel the effect of conical refraction.

Polygonal planforms and phyllotaxis on plants.

We demonstrate how phyllotaxis (the arrangement of leaves on plants) and the ribbed, hexagonal, or parallelogram planforms on plants can be understood as the energy-minimizing buckling pattern of a compressed sheet (the plant's tunica) on an elastic foundation. The key idea is that the elastic energy is minimized by configurations consisting of special triads of periodic deformations. We study the conditions that lead to continuous or discontinuous transitions between patterns, state testable predictions, and suggest experiments to test the theory.

Multicentre audit of the treatment of uncomplicated urinary tract infection in South Thames.

A regional audit report on the management of uncomplicated urinary tract infections (UTIs) in genitourinary (GU) medicine clinics in the UK in South Thames (South London, Kent, Surrey and Sussex). The majority of centres use trimethoprim as first-line treatment for uncomplicated UTIs. The incidence of trimethoprim resistance was 22.6%. The group has therefore recommended that cephalexin should be the first choice antibiotic for suspected UTIs within GU medicine.

Renal medullary carcinoma metastatic to the orbit: a clinicopathologic report.

A 39-year-old black man with sickle cell trait presented with a rapidly progressive, painful proptosis of the left eye. A computed tomographic scan was interpreted as revealing a cavernous hemangioma. Medial orbitotomy revealed a hard, gray mass supranasal to the optic nerve and invading the medial rectus muscle. Intraoperative frozen section specimens were read initially by the pathologist as metastatic adenocarcinoma. On gross examination, the conspicuous hemorrhage, necrosis, and bright yellow color characteristic of renal cell carcinoma were not present. Final pathologic analysis of the orbital lesion revealed metastatic renal medullary cell carcinoma. The primary lesion was located in the right kidney. Renal medullary carcinoma is a rare tumor, often affecting young individuals with sickle cell trait or disease. We report the first confirmed case of renal medullary carcinoma metastatic to the orbit with orbital symptoms preceding the diagnosis of the primary tumor.

Gonorrhoea in a south London genitourinary medicine department.

The management and outcome of all cases of gonorrhoea which presented to a south London genitourinary medicine clinic during 1999 were assessed and compared with published national guidelines. The incidence of penicillin resistance was calculated, as was the rate of co-infection with chlamydia and trichomonas. Information regarding demographic data, microscopy, culture results, test of cure, antibiotic use, sensitivity and health adviser contact was examined. A total of 257 cases of gonorrhoea were diagnosed in 238 patients. Heterosexual men constituted 52.9% of cases, 6.6% were in homosexual men and 40.5% in women. Direct microscopy was positive in 88.8% of men and in 40.5% of women. In women, the rate of gonorrhoea co-infection with chlamydia was 34.7% and with trichomonas was 11.5%. In men the rate of chlamydia co-infection was only 3.3%, however, we do not believe this to be an accurate figure as we are unable to routinely screen all men for chlamydia due to financial restrictions. Amoxicillin with probenecid were the most commonly used antibiotics in line with local guidelines. Penicillin resistance was demonstrated in 4.6% of infected cases. Health advisers saw 73.2% of patients.

Issues in conducting randomized controlled trials of health services research interventions in nonacademic practice settings: the case of retail pharmacies.

OBJECTIVE: To describe unexpected challenges and strategies to overcome them when conducting randomized controlled trials (RCT) of health services research interventions in retail pharmacies. STUDY SETTING: Thirty-six retail drug stores in Indianapolis. STUDY DESIGN: We conducted an RCT to evaluate the effectiveness of an intervention to increase pharmacists' involvement in caring for customers. We describe: (1) our RCT as originally designed, (2) unexpected challenges we faced; and (3) how we resolved those challenges. DATA COLLECTION/EXTRACTION METHODS: Randomized controlled trial. PRINCIPAL FINDINGS: Major modifications in research design were necessitated by factors such as corporate restructuring, heightened sensitivity to patient confidentiality, and difficulties altering employees' behavior. We overcame these barriers by conducting research that is consistent with corporate goals, involving appropriate corporate administrators and technical personnel early in the process, and being flexible. CONCLUSIONS: Health services researchers should conduct RCTs in a variety of non-academic practice settings to increase generalizability and better reflect the true impact of interventions. Pragmatic problems, although significant, can be successfully overcome.

Effectiveness of pharmacist care for patients with reactive airways disease: a randomized controlled trial.

CONTEXT: It is not known whether patient outcomes are enhanced by effective pharmacist-patient interactions. OBJECTIVE: To assess the effectiveness of a pharmaceutical care program for patients with asthma or chronic obstructive pulmonary disease (COPD). DESIGN, SETTING, AND PARTICIPANTS: Randomized controlled trial conducted at 36 community drugstores in Indianapolis, Ind. We enrolled 1113 participants with active COPD or asthma from July 1998 to December 1999. Outcomes were assessed in 947 (85.1%) participants at 6 months and 898 (80.7%) at 12 months. INTERVENTIONS: The pharmaceutical care program (n = 447) provided pharmacists with recent patient-specific clinical data (peak expiratory flow rates [PEFRs], emergency department [ED] visits, hospitalizations, and medication compliance), training, customized patient educational materials, and resources to facilitate program implementation. The PEFR monitoring control group (n = 363) received a peak flow meter, instructions about its use, and monthly calls to elicit PEFRs. However, PEFR data were not provided to the pharmacist. Patients in the usual care group (n = 303) received neither peak flow meters nor instructions in their use; during monthly telephone interviews, PEFR rates were not elicited. Pharmacists in both control groups had a training session but received no components of the pharmaceutical care intervention. MAIN OUTCOME MEASURES: Peak expiratory flow rates, breathing-related ED or hospital visits, health-related quality of life (HRQOL), medication compliance, and patient satisfaction. RESULTS: At 12 months, patients receiving pharmaceutical care had significantly higher peak flow rates than the usual care group (P =.02) but not than PEFR monitoring controls (P =.28). There were no significant between-group differences in medication compliance or HRQOL. Asthma patients receiving pharmaceutical care had significantly more breathing-related ED or hospital visits than the usual care group (odds ratio, 2.16; 95% confidence interval, 1.76-2.63; P<.001). Patients receiving pharmaceutical care were more satisfied with their pharmacist than the usual care group (P =.03) and the PEFR monitoring group (P =.001) and were more satisfied with their health care than the usual care group at 6 months only (P =.01). Despite ample opportunities to implement the program, pharmacists accessed patient-specific data only about half of the time and documented actions about half of the time that records were accessed. CONCLUSIONS: This pharmaceutical care program increased patients' PEFRs compared with usual care but provided little benefit compared with peak flow monitoring alone. Pharmaceutical care increased patient satisfaction but also increased the amount of breathing-related medical care sought.

Coherent structures and entropy in constrained, modulationally unstable, nonintegrable systems.

Many studies have shown that nonintegrable systems with modulational instabilities constrained by more than one conservation law exhibit universal long time behavior involving large coherent structures in a sea of small fluctuations. We show how this behavior can be explained in detail by simple thermodynamic arguments.

Resistance patterns of urinary tract infections diagnosed in a genitourinary medicine clinic.

We aimed to assess the prevalence of antibiotic resistance amongst urinary tract isolates within our clinic. Local protocol has been to prescribe a 3-day course of trimethoprim for uncomplicated urinary tract infections (UTIs). Notes of all culture-proven UTIs (October 1998 to September 1999) were examined. Eighty-six urinary isolates were identified in 84 patients. Seventy-three of the isolates were coliforms with 46 being Escherichia coli. Of the 86 urinary isolates 28 (32.6%) were resistant to trimethoprim, 37 (43.5%) to amoxycillin, 5 (5.8%) to cephradine and 3 (3.5%) to nitrofurantoin. Seventy-four (86%) of the UTIs were known to have been treated; 41 at initial presentation and 33 once sensitivities were available. Of the 41 patients who received treatment initially, 11 needed to return to the clinic for a further course of antibiotics. To try and reduce the number of inappropriate treatments and unnecessary visits a number of options regarding clinic protocol were explored.

A placebo-controlled phase I/II study of adefovir dipivoxil in patients with chronic hepatitis B virus infection.

Adefovir dipivoxil (bis-POM PMEA) is an adenine nucleotide analogue with activity against retroviruses and herpesviruses, and in vitro activity against hepatitis B virus (HBV). This study was conducted to evaluate its safety and antiviral activity in patients with chronic HBV infection. Twenty patients (13 co-infected with human immunodeficiency virus, HIV) were randomized in a phase I/II, double-blind, placebo-controlled study. Patients who had been hepatitis B surface antigen (HBsAg)/hepatitis B e antigen (HBeAg) positive for > or = 6 months, with elevated hepatic transaminases and serum HBV DNA > or = 50 pg ml-1, were randomized to adefovir dipivoxil 125 mg (n = 15) or placebo (n = 5) as a single, daily, oral dose for 28 days. Antiviral activity was assessed by changes in serum HBV DNA (using the Digene Hybrid Capture assay) and HBeAg/hepatitis B e antibody (HBeAb) status. HBV DNA levels fell rapidly by > 1 log10 in all active drug recipients (median fall 1.8 log10 pg ml-1) but increased by 0.01 log10 pg ml-1 in controls (P = 0.002). Reductions were sustained during treatment. HBV DNA returned to baseline over 1-6 weeks following discontinuation of active drug. HBeAg became transiently undetectable in one patient on treatment and, in another, sustained seroconversion to HBeAb occurred 12 weeks after treatment ended. Liver transaminase elevations > 300 U l-1 were observed in three patients during therapy (leading to protocol-specified treatment discontinuation or dose reduction) and in four patients during follow-up. On-treatment transaminase elevations were associated with HIV status, occurring in three of six HIV-uninfected patients compared with none of nine who were HIV infected. In addition, a slower return to baseline of serum HBV DNA levels was observed in the non-HIV-infected patients. Treatment for chronic hepatitis B as a once-daily oral dose was well tolerated and associated with significant and sustained reductions in serum HBV DNA levels during treatment. Transaminase elevations, which may be related to the therapeutic effect, were observed during and after treatment. Further studies are warranted to investigate the safety, and optimum dose and duration, of adefovir dipivoxil treatment for chronic hepatitis B.

Risk factors for tuberculosis in patients with AIDS in London: a case-control study.

OBJECTIVE: To identify risk factors for the acquired immune-deficiency syndrome (AIDS) associated with tuberculosis, in patients with AIDS attending 11 of the largest human immunodeficiency virus (HIV)/AIDS Units in London. DESIGN: Case-control study nested in a retrospective cohort of 2048 HIV-1 positive patients. Cases were defined as patients with a definitive diagnosis of tuberculosis, and controls as patients with AIDS and without tuberculosis during follow-up. RESULTS: Of 627 patients diagnosed with AIDS, 121 had a definitive diagnosis of tuberculosis. Significant risk factors for tuberculosis in the univariate analysis were sex, ethnicity, age, HIV exposure category and hospital attended, and in the multiple regression analysis ethnicity, age and hospital attended. African ethnicity was the strongest risk factor for tuberculosis (adjusted odds ratio [AOR] 5.9, 95% confidence interval 3.4-10.2). The risk of tuberculosis was higher in the younger age groups (test for trend P < 0.001). The hospital-associated risk of tuberculosis was more heterogeneous in the non-African group, and non-Africans attending Hospital 1 had an increased risk of tuberculosis which was statistically significant. CONCLUSIONS: The risk factors for AIDS-associated tuberculosis in London are sub-Saharan African origin, younger age group, and, among the non-Africans only, attending one hospital in east London. Different transmission patterns and mechanisms for the development of tuberculosis may operate in different settings depending on the background risk of tuberculous infection. Screening for tuberculosis infection and disease among HIV-positive individuals in London is important for the provision of preventive or curative therapy, and prophylaxis policies need to be designed in accordance with the transmission patterns and mechanisms of disease.