A role for class 3 semaphorins in prostate cancer

BACKGROUND

Class 3 semaphorins are secreted proteins that act as guidance cues for migrating cells via their transmembrane receptors plexins and neuropilins. Semaphorins have a role in cancer affecting tumor progression both directly, and indirectly by affecting angiogenesis.

METHODS

The expression of semaphorins and their receptors in prostate cancer cell lines and tissue was determined by RT-PCR, Western blotting and immunohistochemistry. The effect of Sema3E on prostate cancer cell lines was determined by adhesion assays and transwell migration assays.

RESULTS

Semaphorins and their receptors, plexins and neuropilins, are widely co-expressed in prostate cancer cell lines and tissue with a significant overexpression of Sema3E in tumor tissue. Sema3E affected integrin-mediated adhesion to fibronectin of prostate cancer cells, and inhibited their motility. Expression of Sema3C was upregulated and Sema3A and Sema3E were down regulated in prostate cells by hypoxia, consistent with an additional role for Sema3A and 3E as anti-angiogenic factors in prostate cancer.

CONCLUSIONS

Semaphorin 3E is aberrantly expressed in prostate cancer and affects adhesion and motility of prostate cancer cells, indicating a role for the Sema3E/PlexinD1 signaling pathway in prostate cancer and identifying a new possible target for therapy.

Vertically acquired HIV diagnosed in adolescence and early adulthood in the United Kingdom and Ireland: findings from national surveillance

OBJECTIVE

The aim of the study was to describe the characteristics of young people with vertically acquired HIV diagnosed aged > or =13 years.

METHODS

A retrospective review of HIV diagnoses reported to well-established national paediatric and adult HIV surveillance systems in the United Kingdom/Ireland was conducted.

RESULTS

Forty-two young people with vertically acquired HIV diagnosed aged > or =13 years were identified; 23 (55%) were female, 40 (95%) were black African and 36 (86%) were born in sub-Saharan Africa. The median age at HIV diagnosis was 14 years (range, 13-20 years). Half of the patients presented with symptoms; the remainder were screened for HIV following diagnosis of a relative. The median CD4 count at diagnosis was 210 cells/microL (range, 0-689 cells/microL), 12 patients (29%) were diagnosed with AIDS at HIV diagnosis or subsequently, and 34 (81%) started combination antiretroviral therapy (ART), most (31 of 34) within a year of diagnosis.

CONCLUSION

A small number of young people with vertically acquired HIV survive childhood without ART and are diagnosed at age > or =13 years in the United Kingdom/Ireland. Half of the patients were asymptomatic, highlighting the importance of considering HIV testing for all offspring of HIV-infected women, regardless of age or symptoms. Increased awareness among clinicians and parents is required to reduce delayed presentation with advanced disease and to avoid onward transmission as these young people become sexually active.

Is Antibiotic Prophylaxis Required for Flexible Cystoscopy? A Truncated Randomized Double-Blind Controlled Trial

PURPOSE

To examine the incidence of urinary tract infection (UTI) after flexible cystoscopy (FC) and determine whether prophylactic norfloxacin reduces this incidence compared with placebo.

PATIENTS AND METHODS

A double-blind trial was performed, randomizing 234 patients to either 400 mg of norfloxacin or placebo prior to FC. All patients provided a midstream urine specimen (MSU) before the procedure, as well as at day 3 and day 7 after FC. In addition, a telephone questionnaire was performed to correlate the nature and severity of any symptoms associated with UTI.

RESULTS

Interim analysis was performed because of the low recruitment rate, and a significantly lower infection rate than expected meant that the trial was discontinued. There was one symptomatic UTI in the placebo group (0.82%) and one in the norfloxacin group (0.89%). The UTI in the placebo group was de novo, while the infection in the norfloxacin group was secondary to pre-FC bacteriuria. There was no difference in the infection rates in the two groups. The overall infection rate (de novo and secondary to existing bacteruria) after FC was 0.85%.

CONCLUSION

Infection after flexible cystoscopy is rare and not associated with significant morbidity. A much larger study would be required to determine whether antibiotic prophylaxis significantly reduces the rate of postprocedure UTI.

Decline in mortality, AIDS, and hospital admissions in perinatally HIV-1 infected children in the United Kingdom and Ireland

OBJECTIVE

To describe changes in demographic factors, disease progression, hospital admissions, and use of antiretroviral therapy in children with HIV.

DESIGN

Active surveillance through the national study of HIV in pregnancy and childhood (NSHPC) and additional data from a subset of children in the collaborative HIV paediatric study (CHIPS).

SETTING

United Kingdom and Ireland.

PARTICIPANTS

944 children with perinatally acquired HIV-1 under clinical care.

MAIN OUTCOME MEASURES

Changes over time in progression to AIDS and death, hospital admission rates, and use of antiretroviral therapy.

RESULTS

944 children with perinatally acquired HIV were reported in the United Kingdom and Ireland by October 2002; 628 (67%) were black African, 205 (22%) were aged > or = 10 years at last follow up, 193 (20%) are known to have died. The proportion of children presenting who were born abroad increased from 20% in 1994-5 to 60% during 2000-2. Mortality was stable before 1997 at 9.3 per 100 child years at risk but fell to 2.0 in 2001-2 (trend P < 0.001). Progression to AIDS also declined (P < 0.001). From 1997 onwards the proportion of children on three or four drug antiretroviral therapy increased. Hospital admission rates declined by 80%, but with more children in follow up the absolute number of admissions fell by only 26%.

CONCLUSION

In children with HIV infection, mortality, AIDS, and hospital admission rates have declined substantially since the introduction of three or four drug antiretroviral therapy in 1997. As infected children in the United Kingdom and Ireland are living longer, there is an increasing need to address their medical, social, and psychological needs as they enter adolescence and adult life.

Evolution of the beta defensin 2 gene in primates

With the aim of further investigating the molecular evolution of beta defensin genes, after having analysed beta defensin 1 (DEFB1) in humans and several nonhuman primate species, we have studied the evolution of the beta defensin 2 gene (DEFB2), which codifies for a peptide with antimicrobial and chemoattractant activity, in humans and 16 primate species. We have found evidence of positive selection during the evolution of orthologous DEFB2 genes at two points on a phylogenetic tree relating these primates: during the divergence of the platyrrhines from the catarrhines and during the divergence of the Cercopithecidae from the Hylobatidae, Great Apes and humans. Furthermore, amino acid variations in Old World Monkeys seem to centre either on residues that are involved in oligomerisation in the human molecule, or that are conserved (40-80%) in beta-defensins in general. It is thus likely that these variations affect the biological function of the molecules and suggest that their synthesis and functional analysis might reveal interesting new information as to their role in innate immunity.

Role of the serine-threonine kinase PAK-1 in myxoma virus replication

Subversion or appropriation of cellular signal transduction pathways is a common strategy employed by viruses to promote an environment within infected cells that supports the viral replicative cycle. Using subsets of 3T3 murine fibroblasts previously shown to differ in their ability to support myxoma virus (MV) replication, we investigated the role of host serine-threonine kinases (STKs) as potential mediators of the permissive phenotype. Both permissive and nonpermissive 3T3 cells supported equivalent levels of virion binding, entry, and early virus gene expression, indicating that MV tropism in 3T3 cells was not determined by receptor-mediated entry. In contrast, late virus gene expression and viral DNA replication were selectively compromised in restrictive 3T3 cells. Addition of specific protein kinase inhibitors, many of which shared the ability to influence the activity of the STKs p21-activated kinase 1 (PAK-1) and Raf-1 attenuated MV replication in permissive 3T3 cells. Western blot detection of the phosphorylated forms of PAK-1 (Thr423) and Raf-1 (Ser338) confirmed activation of these kinases in permissive cells after MV infection or gamma interferon treatment, but the activated forms of both kinases were greatly reduced or absent in restrictive 3T3 cells. The biological significance of these activations was demonstrated by using the autoinhibitory domain of PAK-1 (amino acids 83 to 149), expression of which reduced the efficiency of MV infection in permissive 3T3 cells concurrent with a decrease in PAK-1 activation. In comparison, overexpression of a constitutively active PAK-1 (T423E) mutant increased MV replication in restrictive 3T3 cells. These observations suggest that induced signaling via cellular STKs may play important roles in determining the permissiveness of host cells to poxvirus infection.

Poxvirus infection rapidly activates tyrosine kinase signal transduction

Viruses have evolved a number of strategies to gain entry and replicate in host target cells that, for human immunodeficiency virus (HIV) and the poxvirus, myxoma virus, involve appropriating chemokine receptors. In this report we demonstrate that activation of multiple intracellular tyrosine phosphorylation events rapidly ensues following virus adsorption to NIH 3T3.CD4.CCR5 cells and affects the ultimate level of myxoma virus replication. UV-inactivated myxoma virus induces the rapid phosphorylation of CCR5 on tyrosine residues, the association of CCR5 with Jaks and p56(lck), and their phosphorylation-activation within minutes of virus adsorption. Additionally, we provide evidence for myxoma virus-inducible signal transducers and activators of transcription (Stat) and insulin receptor substrate (IRS) activation. In contrast to CCR5 activation effected by HIV Env protein, these myxoma virus-inducible phosphorylation events are not sensitive to pertussis toxin treatment. Moreover, in cells that are non-permissive for myxoma virus infection, we provide evidence that myxoma virus fails to invoke this tyrosine phosphorylation cascade. Consistent with the observation that infection of CCR5-expressing cells is blocked by herbimycin A and the Jak 2 inhibitor, tyrophostin AG490, we infer that viral infectivity may be dependent on non-G-protein-coupled signal transduction pathways triggered by the infecting myxoma virus particle. This provides a novel post-binding mechanism by which viruses can co-opt a cellular receptor to permit productive virus infection.

Development of an enhanced anticaries efficacy dual component dentifrice containing sodium fluoride and dicalcium phosphate dihydrate

A dual-chamber dentifrice, which contains sodium fluoride (NaF) in one component and dicalcium phosphate dihydrate (dical) in the other, has been developed. The dentifrice is packaged in a dual-chamber tube and is formulated to deliver 1100 ppm F. A series of studies consisting of in vitro fluoride uptake, in vivo calcium labeling, intraoral remineralization-demineralization, and animal caries studies were performed to support the improved anticaries efficacy of this product in comparison to a sodium fluoride/silica dentifrice (NaF/silica). An in vitro fluoride uptake study comparing 1100 ppm F NaF/dical dentifrice to 1100 ppm F NaF/silica showed that NaF/dical delivered significantly more fluoride than NaF/silica, 3.72 +/- 0.36 micrograms/cm2 versus 2.41 +/- 0.10 micrograms/cm2. A 6-day in vivo brushing study with a 44Ca labeled NaF/dical dentifrice showed that calcium from dical penetrated demineralized enamel and was present in plaque up to 18 hrs since the last brushing. An intra-oral remineralization-demineralization study was performed to evaluate NaF/dical's ability to promote remineralization in comparison to three silica-based dentifrices containing 0, 250, and 1100 ppm F as NaF. The percent mineral changes after treatment were +20.44 +/- 17.14 for NaF/dical, +9.27 +/- 19.53 for 1100 ppm NaF/silica, -1.43 +/- 20.57 for 250 ppm NaF/silica, and -12.36 +/- 32.76 for 0 ppm F/silica. A statistical analysis showed that the dual-chamber NaF/dical dentifrice was significantly more effective than the 1100 ppm NaF/silica dentifrice at promoting remineralization. A rat caries study was performed to evaluate NaF/dical ability to prevent caries in comparison to 1100 ppm F NaF/silica, 250 ppm F NaF/silica, silica, and dical dentifrices. The mean smooth surface caries scores were 1.6 +/- 2.8 for NaF/dical, 5.5 +/- 6.2 for 1100 ppm F NaF/silica, 10.6 +/- 6.2 for 250 ppm F NaF/silica, 13.7 +/- 4.7 for 0 ppm F/silica, and 9.5 +/- 7.8 0 ppm F/dical. A statistical analysis showed that the the dual-chamber NaF/dical dentifrice was superior to all other treatments tested in preventing caries in rats. The dical dentifrice was significantly superior to the silica dentifrice in preventing caries, which indicates that dical alone exhibits anticaries efficacy. In conclusion, individual and cumulative results from the fluoride uptake, intra-oral remineralization-demineralization, and rat caries studies from the dual chamber NaF/dical dentifrice support the improved anticaries efficacy of this product.

Pneumocystis carinii pneumonia and cytomegalovirus infection in children with vertically acquired HIV infection

OBJECTIVES

The outcome of Pneumocystis carinii pneumonia (PCP) in HIV-infected infants is poor, and the role of cytomegalovirus (CMV) co-infection in the course and outcome of PCP is unclear. This study describes the prevalence, clinical characteristics, management and changes in survival over time of vertically HIV-infected infants developing PCP and/or CMV infection.

METHODS

Data on children with HIV, born in the UK and Ireland and reported to the National Study of HIV in Pregnancy and Childhood, with PCP and/or CMV were combined with clinical information collected from reporting paediatricians.

RESULTS

By April 1998, 340 vertically HIV-infected children had been reported, of whom 93 had PCP and/or CMV, as their first AIDS indicator disease; 85 (91%) were infants. Among infants with PCP, 79% were born to mothers not diagnosed as HIV infected, and there was an independent and statistically significant association with breast-feeding, being black African, and developing CMV disease. Median survival after PCP and/or CMV was significantly better in those born between 1993 and 1998 compared with those born before 1993 (P = 0.009), and worse than after other AIDS diagnoses (P = 0.01). Infants with dual infection were more likely to be ventilated (P = 0.003) and receive corticosteroids (P = 0.002) than those with PCP alone.

CONCLUSION

Although survival from PCP and CMV has improved over time, these remain serious and potentially fatal infections among infants in whom maternal HIV status is not recognized in pregnancy. Breast-feeding increases the risk of combined PCP and CMV infection, which is associated with severe disease.

Please pass the cauliflower: a recipe for introducing undergraduate students to brain structure and function

Neurophysiology/pathophysiology content is a frequent source of anxiety for undergraduate students and their instructors. This learning module supplements traditional lecture and overhead presentations to offer a novel, nonthreatening, and entertaining introduction to neuropathology. The module is based on a ridiculous analogy between the human brain and the cauliflower. This module has been used with both underclassmen and more advanced health science undergraduate students and has produced enthusiastic student responses while deescalating both student and instructor anxiety.

Correlates of social development in children with communication disorders: the concurrent predictive value of verbal short-term memory span

Linguistic and cognitive correlates of social skill were examined in a clinically selected sample of children with communication disorders. Thirty-two children aged between 5 and 10 years were assessed using a questionnaire-based sociability scale. Specially designed measures of verbal and visuo-spatial short-term memory span were administered, as well as standardized tests of grammatical and lexical comprehension. Multiple regression analyses revealed strong prediction of social skill from STM measures but not from comprehension scores. The prediction was based on a striking negative correlation between serial word span and sociability. This word-span measure could offer a useful tool in the assessment of children with communication disorders. However, attention is drawn to the substantial number of children in the sample whose patterns of cognitive, linguistic and social skill are not clearly differentiated. It is suggested that assessment should aim to specify as clearly as possible individual patterns of strength and weakness and avoid unwarranted categorization.

Use of chemokine receptors by poxviruses

Chemokine receptors serve as portals of entry for certain intracellular pathogens, most notably human immunodeficiency virus (HIV). Myxoma virus is a member of the poxvirus family that induces a lethal systemic disease in rabbits, but no poxvirus receptor has ever been defined. Rodent fibroblasts (3T3) that cannot be infected with myxoma virus could be made fully permissive for myxoma virus infection by expression of any one of several human chemokine receptors, including CCR1, CCR5, and CXCR4. Conversely, infection of 3T3-CCR5 cells can be inhibited by RANTES, anti-CCR5 polyclonal antibody, or herbimycin A but not by monoclonal antibodies that block HIV-1 infection or by pertussis toxin. These findings suggest that poxviruses, like HIV, are able to use chemokine receptors to infect specific cell subtypes, notably migratory leukocytes, but that their mechanisms of receptor interactions are distinct.

Vertical transmission rates for HIV in the British Isles: estimates based on surveillance data

OBJECTIVE

To estimate and interpret time trends in vertical transmission rates for HIV using data from national obstetric and paediatric surveillance registers.

DESIGN

Prospective study of HIV infected women reported through obstetric surveillance. HIV infection status of the child and onset of AIDS were reported through paediatric surveillance. Rates of vertical transmission and progression to AIDS rate were estimated by methods that take account of incomplete follow up of children with indeterminate infection status and delay in AIDS reporting.

SETTING

British Isles.

SUBJECTS

Pregnant women infected with HIV whose infection was diagnosed before delivery, and their babies.

MAIN OUTCOME MEASURES

Mother to child transmission of infection and progression to AIDS in children.

RESULTS

By January 1999, 800 children born to diagnosed HIV infected women who had not breast fed had been reported. Vertical transmission rates rose to 19.6% (95% confidence interval 8. 0% to 32.5%) in 1993 before falling to 2.2% (0% to 7.8%) in 1998. Between 1995 and 1998 use of antiretroviral treatment increased significantly each year, reaching 97% of live births in 1998. The rate of elective caesarean section remained constant, at around 40%, up to 1997 but increased to 62% in 1998. Caesarean section and antiretroviral treatment together were estimated to reduce risk of transmission from 31.6% (13.6% to 52.2%) to 4.2% (0.8% to 8.5%). The proportion of infected children developing AIDS in the first 6 months fell from 17.7% (6.8% to 30.8%) before 1994 to 7.2% (0% to 15. 7%) after, coinciding with increased use of prophylaxis against Pneumocystis carinii pneumonia.

CONCLUSIONS

In the British Isles both HIV related morbidity and vertical transmission are being reduced through increased use of interventions.

Incidence of symptomatic toxoplasma eye disease: aetiology and public health implications

Ocular disease is the commonest disabling consequence of toxoplasma infection. Incidence and lifetime risk of ocular symptoms were determined by ascertaining affected patients in a population-based, active reporting study involving ophthalmologists serving a population of 7.4 million. Eighty-seven symptomatic episodes were attributed to toxoplasma infection. Bilateral visual acuity of 6/12 or less was found in seven episodes (8%) and was likely to have been transient in most cases. Black people born in West Africa had a 100-fold higher incidence of symptoms than white people born in Britain. Only two patients reported symptoms before 10 years of age. The estimated lifetime risk of symptoms in British born individuals (52% of all episodes) was 18/100000 (95% confidence interval: 10.8-25.2). The low risk and mild symptoms in an unscreened British population indicate limited potential benefits of prenatal or postnatal screening. The late age at presentation suggests a mixed aetiology of postnatally acquired and congenital infection for which primary prevention may be appropriate, particularly among West Africans.

Role of the myxoma virus soluble CC-chemokine inhibitor glycoprotein, M-T1, during myxoma virus pathogenesis

Myxoma virus is a poxvirus that causes a virulent systemic disease called myxomatosis in European rabbits. Like many poxviruses, myxoma virus encodes a variety of secreted proteins that subvert the antiviral activities of host cytokines. It was recently demonstrated that the myxoma virus M-T1 glycoprotein is a member of a large poxvirus family of secreted proteins that bind CC-chemokines and inhibit their chemoattractant activities in vitro. To determine the biological role of M-T1 in contributing to myxoma virus virulence, we constructed a recombinant M-T1-deletion mutant virus that was defective in M-T1 expression. Here, we demonstrate that M-T1 is expressed continuously during the course of myxoma virus infection as a highly stable 43-kDa glycoprotein and is dispensable for virus replication in vitro. Deletion of M-T1 had no significant effects on disease progression or in the overall mortality rate of infected European rabbits but heightened the localized cellular inflammation in primary tissue sites during the initial 2 to 3 days of infection. In the absence of M-T1 expression, deep dermal tissues surrounding the primary site of virus inoculation showed a dramatic increase in infiltrating leukocytes, particularly monocytes/macrophages, but these phagocytes remained relatively ineffective at clearing virus infection, likely due to the concerted properties of other secreted myxoma virus proteins. We conclude that M-T1 inhibits the chemotactic signals required for the influx of monocytes/macrophages during the acute-phase response of myxoma virus infection in vivo, as predicted by its ability to bind and inhibit CC-chemokines in vitro.

Performance of antenatal HIV screening strategies in the United Kingdom

BACKGROUND

In 1996 only 13.5% of previously undiagnosed HIV infected women were detected in pregnancy. In this study, all 265 maternity units in the United Kingdom were surveyed to determine the relation between screening strategy, uptake of testing, and detection rate.

METHODS

Data on HIV screening strategy and uptake of testing were collected in 1997 by postal questionnaire. The proportion of women with previously undiagnosed HIV infection identified during pregnancy (detection rate) was calculated using data from national obstetric HIV surveillance and unlinked anonymous seroprevalence studies.

RESULTS

239 (90%) units responded; 25 of these (10%) had a universal offer strategy, 89 (37%) a selective offer, and 125 (52%) tested only women who requested it. All selective units offered testing to injecting drug users, but only 26% to women who had lived abroad in high prevalence areas. Uptake was over 10% in only eight units, all with a universal strategy, and in 76% of selective units it was below 0.1%. The detection rate was 14.7% in universal units, 7.8% in selective units, and 7.7% in on request units. In universal units, detection increased by 6.3% (95% confidence interval 3.7% to 8.8%) for every 10% increase in uptake of testing. There was evidence of both selective presentation for testing and avoidance of testing among infected women.

CONCLUSIONS

All current antenatal HIV testing strategies fail to identify most infected women. Universal offer strategies achieve a very low uptake and a poor detection rate. Units with selective strategies tend to test only a minority of women at high risk and do not target all the main high risk groups.

A family clinic--optimising care for HIV infected children and their families

A family clinic providing specialist paediatric and adult medical, testing, counselling, and terminal care services for families living with HIV was set up at a paediatric tertiary care hospital in London in 1991. During the first five years, until April 1996, 185 children from 149 families attended, including 119 infected children, of whom 32 have died. Only 5% of mothers were born in the UK; the rest were born in 24 different countries, the majority in sub-Saharan Africa. Less than a quarter of children were cared for by both parents, 61% by mothers alone, and 11% by guardians or foster parents. Of the adult attendees, 76% were women, and more than half were untested when they first attended the clinic. Provision of a family planning service within the family clinic was initiated as a result of women presenting with unplanned pregnancies. Shared care with local clinics is increasing, but with the complexity around the management of paediatric HIV infection, particularly with regard to antiretroviral treatments, there is need for continued specialist input. Coordination among specialist and locally based family services is required to provide flexible, accessible, and up to date care for families living with HIV infection in London.

Persistence of antibody responses to Haemophilus influenzae type b polysaccharide conjugate vaccine in children with vertically acquired human immunodeficiency virus infection

BACKGROUND

Recurrent bacterial sepsis is common in pediatric HIV infection and immunization against Haemophilus influenzae type b (Hib) is recommended. Long term persistence of anti-Hib antibody and the need for, or timing of, a booster dose has not been adequately studied.

METHODS

Immunogenicity during a 12-month period following immunization with Hib-tetanus conjugate vaccine (ACT-HIB; Merieux) was evaluated in 48 vertically HIV-infected children and 36 uninfected children, born to HIV-positive mothers. A titer of anti-Hib polysaccharide antibody of > or = 0.15 microgram/ml was considered to indicate short term and > or = 1 microgram/ml long term protection.

RESULTS

At 1 month postvaccination 36 (100%) uninfected and 42 (88%) HIV-infected children achieved titers of > or = 1 microgram/ml. However, by 1 year titers had dropped below this value in 18 (43%) infected compared with only 4 (11%) uninfected children (chi square, 9.7; P = 0.002). Although the rate of fall of antibody titer was greater in uninfected than in infected children, this was no longer the case after adjustment for the 1-month postimmunization titer. The rate of antibody titer decline was not significantly related to HIV disease status or to either the age-related CD4 count at the time of immunization or the change in age-adjusted CD4 count during the 12 months after immunization.

CONCLUSIONS

Not only was the initial antibody response to Hib conjugate vaccine decreased in children with HIV infection and AIDS but also 1 year later only 57% of the initial responders had persisting titers above the level associated with long term protection. The need for reimmunization of children with HIV infection against Hib requires further evaluation.