Use of prednisolone to aid propagation of Toxoplasma gondii in mice

AIM

To determine the usefulness of prednisolone in increasing the number of Toxoplasma (T.) gondii tachyzoites and bradyzoites in mice.

MATERIALS AND METHODS

The mice were water-fasted prior to being immunosuppressed with oral inoculation of prednisolone. Tachyzoites of 7T gondii RH strain were inoculated into mice and the number of the parasites in the intraperitoneal fluids was then determined at 96 hs post-infection. In addition, tachyzoites of T. gondii ME49 strains were orally introduced into mice and the number of brain cysts formed was observed by microscopic observation at 45 days post-infection.

RESULTS

T. gondii propagation was found to be significantly improved by introduction of the prednisolone (p = 0.0004); and the number of parasite showed positive correlation with the increment in dosage of prednisolone (r = 0.9051).

CONCLUSIONS

The use of prednisolone greatly improved the number of parasite formed in mice: both tachyzoite and cyst forms.

Accelerating consensus on coevolving networks: the effect of committed individuals

Social networks are not static but, rather, constantly evolve in time. One of the elements thought to drive the evolution of social network structure is homophily-the need for individuals to connect with others who are similar to them. In this paper, we study how the spread of a new opinion, idea, or behavior on such a homophily-driven social network is affected by the changing network structure. In particular, using simulations, we study a variant of the Axelrod model on a network with a homophily-driven rewiring rule imposed. First, we find that the presence of rewiring within the network, in general, impedes the reaching of consensus in opinion, as the time to reach consensus diverges exponentially with network size N. We then investigate whether the introduction of committed individuals who are rigid in their opinion on a particular issue can speed up the convergence to consensus on that issue. We demonstrate that as committed agents are added, beyond a critical value of the committed fraction, the consensus time growth becomes logarithmic in network size N. Furthermore, we show that slight changes in the interaction rule can produce strikingly different results in the scaling behavior of consensus time, T(c). However, the benefit gained by introducing committed agents is qualitatively preserved across all the interaction rules we consider.

A study of adverse drug reactions in pediatric patients

Aim:

To study the adverse drug reaction (ADR) pattern in a pediatric population in a tertiary care hospital.

Materials and Methods:

An observational study was done in the department of pediatrics in a tertiary care hospital. The ADRs occurring in the inpatient wards and outpatient department of pediatrics were actively monitored. The collected reports were analyzed for ADR pattern, drug groups, demographic profile, causality, severity, and preventability of the ADR.

Results:

A total of 30 ADRs were documented during the mid period of 2009 among pediatric patients. Most of the ADRs (60%) occurred below the age of 1 year. Antibiotics comprised the major group of drugs causing ADRs (67%). Rashes and urticaria were the most common type of ADR (37%) followed by fever, anaphylactic shock, vomiting, chills, and rigors. A single case of death had been reported in the study period. There were more occurrences of ADRs with multiple drugs compared to single drug therapy. About 80% of the ADRs were of probable causality and 87% were of probable preventability. There were no mild reactions, with 77% of reactions being moderate and 23% of reactions being severe in the severity scale.

Conclusions:

ADRs occur more among infants and antibiotics were more commonly implicated. Most of the reactions were of moderate severity. This indicates the need for a rigid ADR monitoring among pediatric patients to ensure safety of drug therapy.

Social consensus through the influence of committed minorities

We show how the prevailing majority opinion in a population can be rapidly reversed by a small fraction p of randomly distributed committed agents who consistently proselytize the opposing opinion and are immune to influence. Specifically, we show that when the committed fraction grows beyond a critical value p(c) ≈ 10%, there is a dramatic decrease in the time T(c) taken for the entire population to adopt the committed opinion. In particular, for complete graphs we show that when p < pc, T(c) ~ exp [α(p)N], whereas for p>p(c), T(c) ~ ln N. We conclude with simulation results for Erdős-Rényi random graphs and scale-free networks which show qualitatively similar behavior.

Social influencing and associated random walk models: Asymptotic consensus times on the complete graph

We investigate consensus formation and the asymptotic consensus times in stylized individual- or agent-based models, in which global agreement is achieved through pairwise negotiations with or without a bias. Considering a class of individual-based models on finite complete graphs, we introduce a coarse-graining approach (lumping microscopic variables into macrostates) to analyze the ordering dynamics in an associated random-walk framework. Within this framework, yielding a linear system, we derive general equations for the expected consensus time and the expected time spent in each macro-state. Further, we present the asymptotic solutions of the 2-word naming game and separately discuss its behavior under the influence of an external field and with the introduction of committed agents.

Child and adolescent suicide in a large, urban area: psychological, demographic, and situational factors

We examined all completed suicides by children and adolescents in Los Angeles County who died during 1996 and 1997. There were 46 subjects, aged 11 through 16. The majority of the decedents were males and over age 14. The predominant racial group was Hispanic. There was an almost even split between firearms and hanging as the means of death. Females had a statistically significantly higher rate of prior suicide attempts than males. Over one-third left a suicide note, almost one-half were noted to be depressed, and 22% tested positive for alcohol or illicit drugs. Less than one-quarter were in mental health treatment. Eighty-seven percent had difficulty transitioning to or during adolescence; e.g., problems at home, legal and school difficulties, and relationship losses. These findings are discussed in terms of Eriksonian developmental theory. We offer recommendations for intervention and prevention of suicide.

The future of criminal violence: juveniles tried as adults

Juveniles tried as adults (JTA) represent a select and small subsample of juvenile offenders. This study seeks to provide a profile of habitually violent JTAs transferred to the adult penal system and to compare them with their adult counterparts. Twenty-nine incarcerated violent male juveniles tried as adults were compared with a sample of 27 incarcerated violent male offenders across demographic, neuropsychological, criminal history, psychopathy, and substance abuse variables. The JTAs were characterized by a high rate of gang membership (96%), substance abuse (alcohol, marijuana, and phenylcyclidene), and use of guns. In the juvenile sample, 65 percent used guns in violence not leading to arrest, and 93 percent used guns in a violent crime leading to arrest. Juvenile offenders were similar to their adult counterparts in patterns of criminality, although adult offenders had higher psychopathy scores. Both groups revealed generally intact neuropsychological functioning with the exception of a higher rate of perseverative responses in the adult sample. The results are discussed in terms of the implication of the degree of violence in a young offender population.

Psychological factors in the determination of suicide in self-inflicted gunshot head wounds

Self-inflicted contact gunshot wounds to the head have usually been considered presumptive of suicide. This study evaluates whether sufficient psychological data are gathered in such cases to support a manner of death determination of suicide. We suggest that law enforcement agencies and coroner's departments do not fully explore the decedent's state of mind at the time of death. We studied the first 50 consecutive deaths in 1993 in a major metropolitan county due to self-inflicted gunshot wounds to the head. The sample consists primarily of unmarried, white males, with a median age of 35 years, who displayed psychiatric disturbance, primarily depression, before their death. Younger individuals were often under the influence of alcohol and/or drugs at the time of death. Stressors, such as the loss of a loved one, are common among young and middle-aged persons, while serious health problems are found among the majority of middle-aged and elderly individuals. Many of the findings of this study are consistent with the literature regarding individuals who commit suicide. Although data on many important psychological risk factors are missing in most cases, sufficient psychological material is gathered about the decedent's mental condition at the time of death to support a suicide determination.

Actuarial risk assessment models: a review of critical issues related to violence and sex-offender recidivism assessments

Risk assessment in the area of identification of violence has been dichotomized by several prominent researchers as the "clinical approach" versus the "actuarial method". The proponents of the actuarial approach argue for actuarially derived decisions to replace existing clinical practice. The actuarial method requires no clinical input, just a translation of the relevant material from the records to calculate the risk score. A risk appraisal approach based upon a sole actuarial method raises several questions: those of public safety, peer-accepted standards of practice, liability issues, and concordance with evidence-based medicine practice. We conclude that the sole actuarial approach fails to satisfy these critical issues.

Neuropsychological assessment of competency to stand trial evaluations: a practical conceptual model

Competency for adjudication is a complex concept that, despite judicial efforts to articulate functional criteria, has presented conscientious clinicians with the need to filter through multiple levels of psychological data to adequately evaluate and describe the germane functional capacities and deficits of a given defendant. Practitioners are confronted with preparing evaluations that are either psychologically inclusive and too broad to be judicially useful or too brief (opinions with inadequate descriptions of how a specific defendant's abilities and impediments affect the legal criteria). The trend toward harsh sentencing guidelines has further increased defendants' incentives either to postpone adjudication or to attempt to establish a foundation for an insanity plea. Therefore, accurate identification of malingered deficits has become a more significant problem in evaluating competency to stand trial than it previously was. When neuropsychological factors are introduced, competency assessment becomes complex. This article presents a methodology for managing these complexities. Strategies for preparing concise competency evaluations for defendants presenting neuropsychological symptoms are provided along with examples that help illustrate the evaluation process.

Extended civil commitment for dangerous psychiatric patients

Mental health clinicians are increasingly held civilly liable for the dangerous acts of their psychiatric patients. One area of liability is the negligent release of involuntarily committed patients who engage in dangerous acts after their hospital discharge. All states have provisions for extended involuntary commitment for mentally ill dangerous patients. We examined extended civil commitment petitions in Los Angeles County, California, and found that the great majority were rejected. While the standard for extended civil commitment in California includes verbal threats of substantial physical harm, deputy district attorneys tended to reject petitions initiated by clinicians when verbal threats were the sole criterion of dangerousness. This tendency by deputy district attorneys can be quite confusing for clinicians. Mental health professionals' liability has sensitized them to the legal implications of patients' verbal threats of harm; attorneys do not incur the same legal liability and are not so sensitized.