Nasopharyngeal carcinoma: clinical and radiographic findings in children

Nasopharyngeal carcinoma (NPC) in childhood occurs so infrequently that it is not suspected in affected children until the disease has been present for a long time and local spreading has occurred. The survival rates are therefore quite poor. Six children with NPC are described. A massive local lymph node spread simulating lymphoma was present in half of the patients; in the other half the disease was more subtle, presenting with epistaxis and CNS involvement. If an evaluation of the nasopharynx were part of the initial physical examination in children, the diagnosis of NPC would be made earlier and survival rates would improve.     

Low prevalence of <Emphasis Type=Italic>H. pylori</Emphasis> Infection in HIV-Positive Patients in the Northeast of Brazil

Background  

This study conducted in Northeastern Brazil, evaluated the prevalence of H. pylori infection and the presence of gastritis in HIV-infected patients.     

Reintoxication: the release of fat-stored Δ9-tetrahydrocannabinol (THC) into blood is enhanced by food deprivation or ACTH exposure

Background and purpose:

Δ⁹-tetrahydrocannabinol (THC), the main psychoactive constituent of cannabis, accumulates in adipose tissue where it is stored for long periods of time. Here we investigated whether conditions that promote lipolysis can liberate THC from adipocytes to yield increased blood levels of THC.

Experimental approach:

In vitro studies involved freshly isolated rat adipocytes that were incubated with THC before exposure to the lipolytic agent adrenocorticotrophic hormone (ACTH). A complementary in vivo approach examined the effects of both food deprivation and ACTH on blood levels of THC in rats that had been repeatedly injected with THC (10 mg·kg⁻¹) for 10 consecutive days. Lipolysis promoted by ACTH or food deprivation was indexed by measurement of glycerol levels.

Key results:

ACTH increased THC levels in the medium of THC-pretreated adipocytes in vitro. ACTH also enhanced THC release from adipocytes in vitro when taken from rats repeatedly pretreated with THC in vivo. Finally, in vivo ACTH exposure and 24 h food deprivation both enhanced the levels of THC and its metabolite, (-)-11-nor-9-carboxy-Δ⁹-tetrahydrocannabinol (THC-COOH) in the blood of rats that had been pre-exposed to repeated THC injections.

Conclusions and implications:

The present study shows that lipolysis enhances the release of THC from fat stores back into blood. This suggests the likelihood of ‘reintoxication’ whereby food deprivation or stress may raise blood THC levels in animals chronically exposed to the drug. Further research will need to confirm whether this can lead to functional effects, such as impaired cognitive function or ‘flashbacks’.     

A new rat model of portal hypertension induced by intraportal injection of microspheres

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Establishment of human T-cell leukemia virus type I T-cell lymphomas in severe combined immunodeficient mice

Human T-cell leukemia virus type I (HTLV-I) is recognized as the etiologic agent of adult T-cell leukemia (ATL), a disease endemic in certain regions of southeastern Japan, Africa, and the Caribbean basin. Although HTLV-I can immortalize T lymphocytes in culture, factors leading to tumor progression after HTLV-I infection remain elusive. Previous attempts to propagate the ATL tumor cells in animals have been unsuccessful. Severe combined immunodeficient (SCID) mice have previously been used to support the survival of human lymphoid cell populations when inoculated with human peripheral blood lymphocytes (PBL). SCID mice were injected intraperitoneally with PBL from patients diagnosed with ATL, HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), or from asymptomatic HTLV-I-seropositive patients. Many of these mice become persistently infected with HTLV-I. Furthermore, after human reconstitution was established in these mice, HTLV-I-infected cells displayed a proliferative advantage over uninfected human cells. Lymphoblastic lymphomas of human origin developed in animals injected with PBL from two ATL patients. The tumor cells represented outgrowth of the original ATL leukemic clone in that they had monoclonal or oligoclonal integrations of the HTLV-I provirus identical to the leukemic clone and predominantly expressed the cell surface markers, CD4 and CD25. In contrast, cell lines derived by HTLV immortalization of T cells in vitro did not persist or form tumors when inoculated into SCID mice, indicating differences between in vitro immortalized cells and ATL leukemic cells. This system represents the first small animal model to study HTLV-I tumorigenesis in vivo.