Hypothalamic-pituitary-adrenal axis dysfunction as a neurobiological correlate of emotion dysregulation in adolescent suicide

Background

Biological markers of vulnerability for current or future risk of suicide in adolescents could be important adjuncts to the treatment and prevention of this phenomenon.

Data sources

We conducted a PubMed search of all English-language articles published between January 1990 and June 2011 using the following search terms: (??hypothalamic-pituitary-adrenal?? OR ??HPA??) AND (??adolescence?? OR ??adolescent?? OR ??teenager??) AND (??depression?? OR ??major depressive disorder?? OR ??suicidal behavior?? OR ??suicidal ideation?? OR ??suicidal thoughts?? OR ??deliberate self-harm?? OR ??suicidal attempt?? OR ??suicide??).

Results

HPA axis activity can be examined using different methods that do not have the same biological interpretation. An abnormal HPA axis functioning together with an anomalous interaction between HPA mechanisms and other systems such as the serotonergic system may be one of the neurobiological correlates of emotion dysregulation (ED). ED may play an important role in adolescent suicidal behavior. Some psychopathological conditions such as depression or childhood psychological trauma that increase suicidal risk in adolescents are also associated with HPA axis dysregulation. ED, a personality trait, can also be viewed as a predisposing factor that augments the vulnerability to suffer from psychiatric conditions.

Conclusions

Correlating HPA axis dysfunction with psychological factors such as ED could lead to a better understanding of the role of HPA abnormalities in adolescent suicide and may enhance preventive and treatment strategies.     

Influence of Minor Alloying Element Additions on the Crack Susceptibility of a Nickel Based Superalloy Manufactured by LPBF

Inconel 738LC (IN738LC) is a nickel-based superalloy specially used in the hot section components of turbine engines. One of its main drawbacks relies on the cracking susceptibility when it is manufactured by laser powder bed fusion (LPBF). This paper analyzes the influence of minor alloying element concentration on cracking tendency of IN738LC superalloy manufactured by LPBF. For that objective, samples were manufactured using two powders, which presented different minor alloying elements concentration (Si, Zr and B). It was shown that the samples crack tendency was very different depending on the powder used for their manufacturing. In fact, the measured crack density value was 2.73 mm/mm² for the samples manufactured with the powder with higher minor alloying elements concentration, while 0.25 mm/mm² for the others. Additionally, a special emphasis has been put on elemental composition characterization in cracked grain boundaries in order to quantify possible Si or Zr enrichment. It has been also studied the differences of solidification ranges and grain structures between both samples as a consequence of different minor alloying elements concentration in order to analyze their effect on crack susceptibility. In this sense, Scheil-Gulliver simulation results have shown that samples with higher Si and Zr contents presented higher solidification range temperature. This fact, as well as an increase of the presence of high angle grain boundaries (HAGB), leaded to an increment in the crack formation during solidification. Therefore, in this research work, an understanding of the factors affecting crack phenomenon in the LPBF manufactured IN738LC was accomplished.     

Differential expression of c-Met in Kaposi's sarcoma according to progression stage and HIV infection status

Several cytokines, growth factors and the HIV transactivator Tat have been shown to be involved in the pathogenesis of Kaposi's sarcoma (KS). Hepatocyte growth factor/scatter factor (HGF) is an angiogenic cytokine that stimulates proliferation of spindle cells cultured from human KS lesions. The receptor for HGF, the c-Met protein, is expressed by endothelial cells, dermal dendrocytes and KS tumor cells both in vitro and in vivo. KS cells synthesize and secrete HGF and express the hepatocyte growth factor receptor (c-Met), thus providing an autocrine loop for tumor proliferation and neovascularization which can be enhanced by proinflammatory cytokines. We studied the immunohistochemical expression of c-Met in 40 cases of classical Kaposi's sarcoma (C-KS) and AIDS-associated cutaneous Kaposi's sarcoma (AIDS-KS), including 22 plaque stage lesions (12 AIDS-KS cases) and 18 tumor stage lesions (7 AIDS-KS cases). Statistically significant differences in the average intensity of immunohistochemical staining according to the type of lesions progression stages) and the serologic status of the patients were identified. The staining intensity of c-Met was stronger in tumors than in plaques. When only plaques were taken into consideration, the mean staining score was nearly twice as high in C-KS as in AIDS-KS.     

Diagnosis, treatment and prevention of spontaneous bacterial peritonitis

Spontaneous bacterial peritonitis (SBP) is a frequent complication in cirrhotic patients with ascites. Diagnosis of SBP is established by a polymorphonuclear cell count in ascitic fluid > or =250 cells/mm(3). The organism responsible for the infection is isolated in 60-70% of the cases. The remaining cases are considered to have a variant of SBP (culture-negative SBP) and are treated in the same way as those with a positive culture. The SBP resolution rate ranges between 70 and 90%, and hospital survival between 50 and 70%. An early diagnosis and the use of a more adequate antibiotic therapy are the most probable reasons for the improvement in prognosis for SBP in recent decades. Despite the resolution of the infection, SBP may trigger severe complications such as renal impairment, gastrointestinal bleeding and accentuation of hepatic insufficiency which are responsible for the associated mortality. Patients recovering from an episode of SBP should be considered as potential candidates for liver transplantation.     

Light and electron microscopic immunocytochemical visualization of 5-HT1B receptors in the rat brain

Specific antipeptide antibodies were used for the immunohistochemical visualization of 5-HT_1B receptors in the rat brain. A dense, specific 5-HT_1B receptor-like immunoreactivity was found in the globus pallidus, the dorsal subiculum and the substantia nigra. At the light microscope level, immunostaining was diffuse within the neuropil but absent from cell bodies. Observations at the electron microscope level in the substantia nigra showed immunoperoxidase staining in fine unmyelinated axons and nerve terminals.