Effect of sunlight on the infectivity of Cryptosporidium parvum in seawater

The prevalence of pathogenic microorganisms in seawater can result in waterborne and food borne outbreaks. This study was performed to determine the effect of sunlight and salinity on the die-off of Cryptosporidium parvum. Cryptosporidium parvum oocysts, Escherichia coli, and MS2 coliphage were seeded into tap water and seawater samples and then exposed to sunlight. The die-off of C. parvum in seawater, as measured by infectivity, was greater under sunlight (-3.08 log10) than under dark conditions (-1.31 log10). While, no significant difference was recorded in the die-off of C. parvum, under dark conditions, in tap water as compared to seawater (P < 0.05), indicating that the synergistic effect of salinity and sunlight was responsible for the enhanced die-off in seawater. The die-off of MS2 coliphage and E. coli was greater than that observed for C. parvum under all tested conditions. This indicates that these microorganisms cannot serve as indicators for the presence of C. parvum oocysts in seawaters. The results of the study suggest that C. parvum can persist as infectious oocysts for a long time in seawater and can thus pose a serious hazard by direct and indirect contact with humans.     

Chronopotentiometry and Faradaic impedance spectroscopy as signal transduction methods for the biocatalytic precipitation of an insoluble product on electrode supports: routes for enzyme sensors, immunosensors and DNA sensors

The biocatalyzed precipitation of an insoluble product produced on electrode supports is used as an amplification path for biosensing. Enzyme-based electrodes, immunosensors and DNA sensors are developed using this biocatalytic precipitation route. Faradaic impedance spectroscopy and chronopotentiometry are used as transduction methods to follow the precipitation processes. While Faradaic impedance spectroscopy leads to the characterization of the electron-transfer resistance at the electrode, chronopotentiometry provides the total resistance at the interfaces of the modified electrodes. A horseradish peroxidase, HRP, monolayer-functionalized electrode is used to sense H₂O₂ by the biocatalyzed oxidation of 4-chloro-1-naphthol (1), to the insoluble product benzo-4-chlorohexadienone (2). An antigen monolayer electrode is used to sense the dinitrophenyl antibody, DNP-Ab, applying an anti-antibody–HRP conjugate as a biocatalyst for the oxidative precipitation of 1 by H₂O₂ to yield the insoluble product 2. An oligonucleotide (3) functionalized monolayer electrode is used to sense the DNA-analyte (4), that is one of the Tay–Sachs genetic disorder mutants. Association of a biotin-labeled oligonucleotide to the sensing interface, followed by the association of the avidin–HRP conjugate and the biocatalyzed precipitation of 2 leads to the amplified sensing of 4. The amount of the precipitate accumulated on the conductive support is controlled by the concentration of the respective analytes and the time intervals employed for the biocatalytic precipitation of 2. The electron-transfer resistances of the electrodes covered by the insoluble product (2) are derived from Faradaic impedance measurements, whereas the total electrode resistances are extracted from chronopotentiometric experiments. A good correlation between the total electrode resistances and the electron-transfer resistances at the conducting supports are found. Chronopotentiometry is suggested as a rapid transduction means (a few seconds). The precautions needed to apply chronopotentiometry in biosensors are discussed.     

Child sexual abuse--children and families referred to a treatment project and the effects of intervention.

The characteristics of a series of 274 families who were referred to a sexual abuse treatment programme were analysed. Information was obtained on 411 abused children and 362 non-abused children. Different forms of sexual abuse were noted, with 77% of girls and 23% of boys affected. Boys tended to be abused at a younger age, more severely, and for longer periods than girls. There was a predominance of lower social class groups among the parents, and a wide variety of family structures, with reasonable stability over time. Ninety six per cent of perpetrators were men, and biological and step-parents predominated. Contributing factors in both the family history and the current perpetrators and their wives included sexual abuse, violence, chaotic families, marital problems, sexual difficulties, alcoholism, and subnormality. Follow up of 120 families, 180 victims, and 226 siblings showed that prosecution occurred in 60% of cases, with a high percentage of perpetrators being imprisoned. Treatment was offered to 87% of families, but because the treatment programme was in the early stages of development a variable number of children and parents were offered family treatment or treatment in groups for parents and children separately. There was an improvement in the victim''s circumstances in 61% of cases, and a noticeable reduction in "sexualised" and general emotional difficulties among victims, but there was reabuse rate of 16%. Protection of children was achieved through changes of family attitude and changes in family structure including divorce and separation: 14% of victims were rehabilitated to both parents, 33% to mothers only, and 26% to new families or other residences. Consensus in the family that abuse had occurred was seen as an important factor in determining which children could be rehabilitated with both their parents, with their mothers only, or with new families; which families could be offered or accepted treatment; and whether positive changes in the family occurred.     

Risk factors for development of sexually abusive behaviour in sexually victimised adolescent boys: cross sectional study

Objective: To identify factors that may increase the risk of a sexually victimised adolescent boy developing sexually abusive behaviour. Design: Sexually victimised boys who had sexually abused other children were compared with sexually victimised boys who had not done so. Setting: Social services departments in south east England were invited to refer sexually abused and sexually abusing boys to a London postgraduate teaching hospital. Subjects: 25 adolescent boys aged between 11 years and 15 years and 11 months. Main outcome measures: Adjusted odds ratios estimated from unconditional logistic regression. Results: Unadjusted odds rations for witnessing (8.1) as well as experiencing (18.0) intrafamilial violence and discontinuity of care (7.2) discriminated boys who had sexually abused from others who were solely victims of sexual abuse. Only the adjusted odds ratios for witnessing intrafamilial violence (39.7) discriminated the two groups. Conclusions: The risk of adolescent boys who have been victims of sexual abuse engaging in sexually abusive behaviour towards other children is increased by life circumstances which may be unrelated directly to the original abusive experience, in particular exposure to a climate of intrafamilial violence. Our findings have implications for the management of boys found to have been sexually abused and raise important questions about the possibility of secondary prevention of subsequent abusive behaviour in those at greatest risk.

Key messages

• The risk of sexually abused boys in early adolescence abusing other children may be associated with experiences in early life that are independent of sexual victimisation
• Exposure to persistent violence within the family may be a particularly important risk factor
• Management of sexually abused boys should take into account the impact of early life experiences that may be associated with increased risk with a view to the secondary prevention of sexually abusive behaviour

     

BCKDK regulates the TCA cycle through PDC in the absence of PDK family during embryonic development

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CD74 is a regulator of hematopoietic stem cell maintenance

Hematopoietic stem and progenitor cells (HSPCs) are a small population of undifferentiated cells that have the capacity for self-renewal and differentiate into all blood cell lineages. These cells are the most useful cells for clinical transplantations and for regenerative medicine. So far, it has not been possible to expand adult hematopoietic stem cells (HSCs) without losing their self-renewal properties. CD74 is a cell surface receptor for the cytokine macrophage migration inhibitory factor (MIF), and its mRNA is known to be expressed in HSCs. Here, we demonstrate that mice lacking CD74 exhibit an accumulation of HSCs in the bone marrow (BM) due to their increased potential to repopulate and compete for BM niches. Our results suggest that CD74 regulates the maintenance of the HSCs and CD18 expression. Its absence leads to induced survival of these cells and accumulation of quiescent and proliferating cells. Furthermore, in in vitro experiments, blocking of CD74 elevated the numbers of HSPCs. Thus, we suggest that blocking CD74 could lead to improved clinical insight into BM transplant protocols, enabling improved engraftment.

Hematopoietic stem and progenitor cells (HSPCs) can self-renew and differentiate into all blood cell lineages, making them useful for clinical transplantations and regenerative medicine. This study shows that blocking the MIF receptor CD74 increases the accumulation of HSPCs and could improve the efficacy of bone marrow transplantation protocols.