Archive for May, 2009

Patients with depressive disorder, their co-morbidity, visiting rate and disability in relation to self-evaluation of physical and mental health: a cross-sectional study in family practice

Sunday, May 31st, 2009

Background:
High prevalence of depression among primary care patients has increased the need for more research in this field. The objectives of our study were to analyse how depressed patients evaluate their health; which co-morbid diseases are associated with depression; how depression influences the patients’ consultation rate in family practice (FP); how disability is associated with depression; and how depression influences the patients’ working ability.
Methods:
A cross-sectional study, part of the PREDICT study. The study group was formed of 1094 consecutive patients from 23 FPs across Estonia, aged 18-75 years, attending a FP to consult the family doctor (FD). Occurrence of major depression during six months was estimated using the Depression Section of the Composite International Diagnostic Interview. The medical records of all patients were analysed concerning co-morbid diseases, number of visits to the FD, and disability. Every patient filled in questionnaires to assess health-related risk factors for depression, and the SF-12 Health Survey to assess functioning and the perception of health.
Results:
Depression was found in 230 (21%) of the patients. Depressed patients reported less accomplishment owing to emotional problems (OR 1.80; 95% CI 1.18-2.72), being less careful as usual (OR 1.81; 95% CI 1.26-2.60), and having pain that extremely interfered with their normal work (OR 2.50; 95% CI 1.33-4.70) in comparison with non-depressed patients. Also depressed patients were more days on sick-leave (OR 1.00; 95% CI 1.00-1.01) than non-depressed patients. However, analysis of the medical records did not indicate that depressed patients consulted the FD more or had more co-morbid diagnoses than the non-depressed patients.
Conclusions:
Depressed patients may have low self-reported functioning due to emotional problems, pain, and their working ability may have decreased; however, the patients of both groups have an equal number of co-morbid diagnoses and their consultation rate is similar.

Co-morbid disorders and sexual risk behavior in Nigerian adolescents with bipolar disorder

Sunday, May 31st, 2009

Background:
Adolescent onset bipolar disorder often presents with co-morbid disorders of which psychoactive substance use disorders are notable. Mania symptoms and co-morbid psychoactive substance use disorders prone adolescents with bipolar disorder to impulsivity, impaired judgment, and risk taking behavior which often includes sexual risk behavior. There are dearth of information on pattern of co-morbid disorders and sexual risk behavior in adolescent onset bipolar disorder in Nigeria. This study assessed the prevalence and pattern of co-morbid disorders and determined associated factors of sexual risk behavior among adolescents with bipolar disorder.MethodSocio-demographic information was obtained from the adolescents using socio-demographic questionnaire. Clinical interview, physical examination and laboratory investigations were employed to establish co-morbid disorders in these adolescents during the outpatient follow up visits over a one year period.
Results:
A total of forty six (46) adolescents with bipolar disorder were followed up over a one year period. Twenty two (47.8%) of the adolescents had co-morbid disorders with cannabis use disorders, alcohol use disorders, conduct disorder with or without other psychoactive substance use accounting for 23.9%, 8.7%, 13.0% respectively and HIV infection, though a chance finding accounting for 2.2%. Twenty one (45.7%) of the adolescents had positive history of sexual risk behavior, which was significantly associated with presence of co-morbid disorders (p = 0.003), level of religion activities in the adolescents (p = 0.000), and marital status of the parents (p = 0.021).
Conclusion:
When planning interventions for children and adolescents with bipolar disorder, special attention may need to be focused on group of adolescents with co-morbid disorders and propensity towards impulsivity and sexual risk behavior. This may help in improving long term outcome in this group of adolescents.

Parasites may help stabilize cooperative relationships

Sunday, May 31st, 2009

Background:
The persistence of cooperative relationships is an evolutionary paradox; selection should favor those individuals that exploit their partners (cheating), resulting in the breakdown of cooperation over evolutionary time. Our current understanding of the evolutionary stability of mutualisms (cooperation between species) is strongly shaped by the view that they are often maintained by partners having mechanisms to avoid or retaliate against exploitation by cheaters. In contrast, we empirically and theoretically examine how additional symbionts, specifically specialized parasites, potentially influence the stability of bipartite mutualistic associations. In our empirical work we focus on the obligate mutualism between fungus-growing ants and the fungi they cultivate for food. This mutualism is exploited by specialized microfungal parasites (genus Escovopsis) that infect the ant’s fungal gardens. Using sub-colonies of fungus-growing ants, we investigate the interactions between the fungus garden parasite and cooperative and experimentally-enforced uncooperative (”cheating”) pairs of ants and fungi. To further examine if parasites have the potential to help stabilize some mutualisms we conduct Iterative Prisoner’s Dilemma (IPD) simulations, a common framework for predicting the outcomes of cooperative/non-cooperative interactions, which incorporate parasitism as an additional factor.
Results:
In our empirical work employing sub-colonies of fungus-growing ants, we found that Escovopsis-infected sub-colonies composed of cheating populations of ants or fungi lost significantly more garden biomass than sub-colonies subjected to infection or cheating (ants or fungi) alone. Since the loss of fungus garden compromises the fitness of both mutualists, our findings suggest that the potential benefit received by the ants or fungi for cheating is outweighed by the increased concomitant cost of parasitism engendered by non-cooperation (cheating). IPD simulations support our empirical results by confirming that a purely cooperative strategy, which is unsuccessful in the classic IPD model, becomes stable when parasites are included.
Conclusions:
Here we suggest, and provide evidence for, parasitism being an external force that has the potential to help stabilize cooperation by aligning the selfish interests of cooperative partners in opposition to a common enemy. Specifically, our empirical results and IPD simulations suggest that when two mutualists share a common enemy selection can favor cooperation over cheating, which may help explain the evolutionary stability of some mutualisms.

Diagnostic challenges of early Lyme disease: Lessons from a community case series

Sunday, May 31st, 2009

Background:
Lyme disease, the most common vector-borne infection in North America, is increasingly reported. When the characteristic rash, erythema migrans, is not recognized and treated, delayed manifestations of disseminated infection may occur. The accuracy of diagnosis and treatment of early Lyme disease in the community is unknown.
Methods:
A retrospective, consecutive case series of 165 patients presenting for possible early Lyme disease between August 1, 2002 and August 1, 2007 to a community-based Lyme referral practice in Maryland. All patients had acute symptoms of less than or equal to 12 weeks duration. Patients were categorized according to the Centers for Disease Control and Prevention criteria and data were collected on presenting history, physical findings, laboratory serology, prior diagnoses and prior treatments.
Results:
The majority (61%) of patients in this case series were diagnosed with early Lyme disease. Of those diagnosed with early Lyme disease, 13% did not present with erythema migrans; of those not presenting with a rash, 54% had been previously misdiagnosed. Among those with a rash, the diagnosis of erythema migrans was initially missed in 23% of patients whose rash was subsequently confirmed. Of all patients previously misdiagnosed, 41% had received initial antibiotics likely to be ineffective against Lyme disease.
Conclusions:
For community physicians practicing in high-risk geographic areas, the diagnosis of Lyme disease remains a challenge. Failure to recognize erythema migrans or alternatively, viral-like presentations without a rash, can lead to missed or delayed diagnosis of Lyme disease, ineffective antibiotic treatment, and the potential for late manifestations.

The Role of Phosphodiesterase 3 in Endotoxin-Induced Acute Kidney Injury

Sunday, May 31st, 2009

Background:
Acute kidney injury frequently accompanies sepsis. Endotoxin is known to reduce tissue levels of cAMP and low levels of cAMP have been associated with renal injury. We, therefore, hypothesized that endotoxin induced renal injury by activating phosphodiesterase 3 (PDE3) which metabolizes cAMP and that amrinone an inhibitor of PDE3 would prevent the renal injury.
Methods:
Animals were divided into three groups (n = 7/group): 1) Control (0.9% NaCl infusion without LPS); 2) LPS (0.9% NaCl infusion with LPS); 3) Amrinone+LPS (Amrinone infusion with LPS). Either lipopolysaccharide (LPS) or vehicle was injected via the jugular vein and the rats followed for 3 hours. We explored the expression of PDE3 isoenzymes and the concentrations of cAMP in the tissue.
Results:
The PDE3B gene but not PDE3A was upregulated in the kidney of LPS group. Immunohistochemistry also showed that PDE3B was expressed in the distal tubule in the controls and LPS caused PDE3B expression in the proximal as well. However, PDE3A was not expressed in the kidney either in the control or LPS treated groups. Tissue level of cAMP was decreased after LPS and was associated with an increase in blood urea nitrogen, creatinine, ultrastructural proximal tubular changes, and expression of inducible nitric oxide synthase (iNOS) in the endotoxemic kidney. In septic animals the phosphodiesterase 3 inhibitor, amrinone, preserved the tissue cAMP level, renal structural changes, and attenuated the increased blood urea nitrogen, creatinine, and iNOS expression in the kidney.
Conclusion:
These findings suggest a significant role for PDE3B as an important mediator of LPS-induced acute kidney injury.