Trends in the sequence of initiation of alcohol, tobacco, and marijuana use among adolescents in Argentina and Chile from 2001 to 2017.

Background: Variation in drug policies, norms, and substance use over time and across countries may affect the normative sequences of adolescent substance use initiation. We estimated relative and absolute time-varying associations between prior alcohol and tobacco use and adolescent marijuana initiation in Argentina and Chile. Relative measures quantify the magnitude of the associations, whereas absolute measures quantify excess risk.

Possible etiologies for tropical spastic paraparesis and human T lymphotropic virus I-associated myelopathy.

The epidemiology of tropical spastic paraparesis/human T lymphotropic virus I (HTLV-I)-associated myelopathy (TSP/HAM) is frequently inconsistent and suggests environmental factors in the etiology of these syndromes. The neuropathology corresponds to a toxometabolic or autoimmune process and possibly not to a viral disease. Some logical hypotheses about the etiology and physiopathology of TSP and HAM are proposed.

Neutrophils and NADPH oxidase mediate intrapancreatic trypsin activation in murine experimental acute pancreatitis.

Background & Aims: Intrapancreatic activation of digestive enzymes is a key event in the parenchymal cell injury of pancreatitis. We hypothesized that neutrophils recruited to the pancreas during pancreatitis may contribute to such activation.

Methods: To cause experimental pancreatitis, rats and mice were treated with high doses of cerulein.

Localized pancreatic NF-kappaB activation and inflammatory response in taurocholate-induced pancreatitis.

Transcription factor nuclear factor-kappaB (NF-kappaB) is activated in cerulein pancreatitis and mediates cytokine expression. The role of transcription factor activation in other models of pancreatitis has not been established. Here we report upregulation of NF-kappaB and inflammatory molecules, and their correlation with local pancreatic injury, in a model of severe pancreatitis.

Beta-globin gene haplotype characteristics of Colombian Amerinds in South America.

Haplotypes and subhaplotypes in the beta-globin gene cluster were identified in 146 and 156 chromosomes, respectively, of three tribes of Colombian Amerinds. Subhaplotype [+----] was a major one in Colombian Amerinds as in most human ethnic groups except Africans. A major subhaplotype [----+] in Africans was observed in only one chromosome.

Activation of pancreatic acinar cells on isolation from tissue: cytokine upregulation via p38 MAP kinase.

Cytokines produced by pancreatic acinar cells may mediate cell death and recruitment of inflammatory cells into pancreas in pancreatitis and other disorders. Here, we demonstrate mRNA expression for a number of cytokines in acini isolated from rat pancreas. Using RNA from microscopically selected individual cells, we confirmed the acinar cell as a source for cytokine expression.

Cerulein upregulates ICAM-1 in pancreatic acinar cells, which mediates neutrophil adhesion to these cells.

Neutrophil infiltration into the pancreas is a key event in pancreatitis. Here we show that intercellular adhesion molecule-1 (ICAM-1), which regulates neutrophil adhesion, is present on rat pancreatic acinar cells, is upregulated by a hormone (cerulein) and mediates direct binding of neutrophils to acinar cells. ICAM-1 was upregulated in pancreas of rats with experimental pancreatitis induced by supramaximal doses of cerulein.

Characteristic distribution of HTLV type I and HTLV type II carriers among native ethnic groups in South America.

To confirm the geographic and ethnic segregation of HTLV-I and HTLV-II carriers in native populations in South America, we have conducted a seroepidemiological study of native populations in South America, including HTLV-I carriers distributed among seven ethnic groups in the Andes highlands of Colombia, Peru, Bolivia, Argentina, and Chile, and two ethnic groups on Chiloe Island and Easter Island; and HTLV-II carriers distributed among seven ethnic groups of the lowlands along the Atlantic coast of Colombia, Orinoco, Amazon, and Patagonia, and one ethnic group on Chiloe Island. The incidence rate of HTLV-I and HTLV-II carriers varied among the ethnic groups, ranging from 0.8 to 6.

Ethanol diet increases the sensitivity of rats to pancreatitis induced by cholecystokinin octapeptide.

Background & Aims: Although alcoholism is a major cause of pancreatitis, the pathogenesis of this disorder remains obscure. Failure to produce experimental alcoholic pancreatitis suggests that ethanol may only increase predisposition to pancreatitis. This study sought to develop a model of ethanol pancreatitis by determining if an ethanol diet sensitizes rats to pancreatitis caused by cholecystokinin octapeptide (CCK-8).

On the etiology of tropical spastic paraparesis and human T-cell lymphotropic virus-I-associated myelopathy.

The purpose of this review is to present some concepts on the etiology of tropical spastic paraparesis or human T-cell lymphotropic virus-I (HTLV-I)-associated myelopathy (TSP/HAM). The large number of syndromes that have been associated with HTLV-I (60 to date), the existence of TSP/HAM cases associated with other retroviruses (human immunodeficiency virus-2 [HIV-2], HTLV-II), the existence of many TSPs without HTLV-I, and the evidence of clear epidemiologic contradictions in TSP/HAM indicate that the etiopathogenesis of TSP/HAM is not yet clear. Tropical spastic paraparesis/HAM affects patients of all human ethnic groups, but usually in well localized and relatively isolated geographic regions where HTLV-I has been endemic for a long time.

Amelioration of rat cerulein pancreatitis by guamerin-derived peptide, a novel elastase inhibitor.

Increased activity of various proteases is observed in both human and experimental pancreatitis; however, the information on the effects of specific protease inhibitors on the disease is limited. In this study we show that a novel elastase inhibitor, guamerin-derived synthetic peptide (GDSP), improves the parameters of cerulein-induced acute pancreatitis in the rat. The effects of GDSP on pancreatic weight, serum amylase and lipase, morphologic changes in the pancreas, neutrophil infiltration, and nuclear factor KB (NF-KB) activation were measured in rats infused with supramaximal dose of cerulein (5 (g/kg/h) for 6 h.

Early NF-kappaB activation is associated with hormone-induced pancreatitis.

Inflammation and cell death are critical to pathogenesis of acute pancreatitis. Here we show that transcription factor nuclear factor-kappaB (NF-kappaB), which regulates these processes, is activated and plays a role in rat cerulein pancreatitis. NF-kappaB was strongly activated in the pancreas within 30 min of cerulein infusion; a second phase of NF-kappaB activation was prominent at 3-6 h.

Pancreatic acinar cells produce, release, and respond to tumor necrosis factor-alpha. Role in regulating cell death and pancreatitis.

The aim of this study was to determine whether tumor necrosis factor-alpha (TNFalpha) and receptors for TNFalpha are expressed in the exocrine pancreas, and whether pancreatic acinar cells release and respond to TNFalpha. Reverse transcription PCR, immunoprecipitation, and Western blot analysis demonstrated the presence of TNFalpha and 55- and 75-kD TNFalpha receptors in pancreas from control rats, rats with experimental pancreatitis induced by supramaximal doses of cerulein, and in isolated pancreatic acini. Immunohistochemistry showed TNFalpha presence in pancreatic acinar cells.

Molecular phylogeny of human T-cell leukemia virus type I and II of Amerindians in Colombia and Chile.

Six human T-cell leukemia virus type I (HTLV-I) and eight human T-cell leukemia virus type II (HTLV-II) cases newly isolated from the South American countries of Colombia and Chile were analyzed together with the two Amerindian HTLV-I isolates previously reported. All of the HTLV-I isolates belonged to the transcontinental subgroup of the "cosmopolitan" group, and Colombian isolates, including those from native Amerindians and Negroes, formed a single tight cluster within this subgroup. The transcontinental subgroup consisted of isolates from various regions such as the Caribbean basin, India, Iran, South Africa, Sakhalin, and Japan, and included isolates from the "Ainu" and "Okinawa" people, regarded as relatively pure Japanese descended from the prehistoric "Jomon" period which began more than 10,000 years ago.

Mechanisms of cell death after pancreatic duct obstruction in the opossum and the rat.

Background & Aims: Mechanisms of cell death in human and experimental pancreatitis remain poorly understood. The aim of this study was to determine the mechanisms of cell death, apoptosis vs. necrosis, in models of pancreatitis induced by pancreatic duct ligation in the opossum and rat.

[The possible transpacific travel of the adult T-cell leukemia virus I].

Genetical and archeological similarities in both Japanese and South American populations have been described. These facts along with the recent seroepidemiological studied on retroviruses performed in some of those racial groups, and published up to 1993, allow us to suggest that these retroviruses likely arrived to South America, not only from Africa, but also from The Far East since 6000 years ago or earlier. It could occur following the sea-currents directly.

Ethnic segregation of HTLV-I and HTLV-II carriers among South American native Indians.

To investigate the genetic background of human T-cell leukemia virus type I (HTLV-I) and II (HTLV-II) carriers among South American native Indians, we analyzed HLA DRB1*-DQB1* haplotypes of the virus carriers from Andes highlands and Orinoco lowlands by the PCR-RFLP genotyping method. It was revealed that the HTLV-I-carrying Andes natives had one of the 5 HLA haplotypes: DRB1*-DQB1* 0403-0302, 0802-0402, 0901-0303, 1406-0302 and 0407-0302, and that the Orinoco HTLV-II carriers had one of the 3 HLA haplotypes: DRB1*-DQB1* 1402-0301, 1602-0301 and 0404-0302. The HLA haplotypes of Andes HTLV-I carriers and Orinoco HTLV-II carriers were mutually exclusive.

A search for human T-cell leukemia virus type I in the lesions of patients with tropical spastic paraparesis and polymyositis.

We searched for the presence of human T-cell leukemia virus type I (HTLV-I) sequences in central nervous system and muscle lesions of 3 patients with tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM) and 3 patients with HTLV-I-associated polymyositis. Proviral DNA coding for the Tax protein was found by polymerase chain reaction amplification in DNA extracted from lesions of every patient with TSP/HAM or HTLV-I-associated polymyositis. In contrast, viral RNA was found occasionally by in situ hybridization in muscle lesions of some patients with polymyositis, but was never found in central nervous system lesions of TSP/HAM patients.

Tropical spastic paraparesis on the Caribbean coast of Colombia.

Tropical spastic paraparesis (TSP) is a retroviral disease characterized predominantly by a chronic myelopathy and progressive leg weakness. Four patients from the northern coast of Columbia with chronic spastic paraparesis and serum positivity for antibodies to human T cell lymphotropic virus type 1 by enzyme-linked immunosorbent assay and Western blot are reported. All patients had mixed ethnic origins (white, black, and amerindian).

Distribution of HLA and haplotypes of Colombian and Jamaican black populations.

To investigate the genetic background of the black populations of Colombia and Jamaica, we determined HLA types of 78 Colombian and 98 Jamaican blacks from 2 different socioeconomic groups (Jamaican #1 and Jamaican #2) and estimated the frequencies of HLA genes and haplotypes. A phylogenetic tree based on the HLA gene frequencies revealed that Jamaican #1 and Jamaican #2 were distinct from each other, Jamaican #1 being closely related to the Colombian blacks and the Jamaican #2 being closely related to Senegalese and Zairean populations. Three-locus HLA haplotypes of Colombian and Jamaican #1 blacks were an admixture between Africans and Caucasians or South American Indians, while Jamaican #2 blacks were relatively homogeneous and appeared to conserve African lineages.

[Tropical spastic paraparesis (HAM/TSP) in different regions of the world. Subclinical and geographic differences in neurophysiologic studies].

Tropical spastic paraparesis is the same clinical entity all over the world. It has been suggested that some clinical presentation differences are due to not well defined environmental factors that act along with the virus, modifying the start and progression of the disease. We analyzed 25 publications on the disease coming from different parts of the world, aiming to unravel regional differences.

Geographic independence of HTLV-I and HTLV-II foci in the Andes highland, the Atlantic coast, and the Orinoco of Colombia.

To clarify the ethnic specificity of human T cell leukemia virus type I (HTLV-I) and type II (HTLV-II) carriers among Colombian native Indians, we investigated the geographic distribution of HTLV-I and HTLV-II seroprevalence among the isolated ethnic groups of Mongoloid origin in the Andes highlands and the Atlantic coast of Colombia. HTLV-I carriers were found in 1.6% (1/62 samples) of Inga, 8.