Incidence of aplastic anemia in a defined subpopulation from Mexico City

Aplastic anemia (AA) is a hematological disease characterized by the deficient production of blood cells. The incidence of AA worldwide is low (1-5 new cases per 10(6) individuals per year). In contrast to other countries, no current reports exist on the incidence of this disorder in Mexico. In the present study, we have determined the incidence of AA in a defined subpopulation from Mexico City during the period 1996-2000. For the purpose of this study, we focused on the experience from a single medical institution: the Mexican Institute of Social Security (IMSS), which covers around 50% of Mexico's population. The incidence of AA was determined based on the actual number of patients diagnosed with this disease at the IMSS in Mexico City in a given year and the total number of individuals registered at the IMSS in Mexico City in the same year. Considering the IMSS population as a whole, the annual incidence of AA was 3.9 new cases per 10(6) individuals per year. In the pediatric population, the annual incidence was 4.2 new cases per 10(6) individuals per year, whereas in people 15-years-old and older the incidence was 3.8 new cases per 10(6) individuals per year. These incidences were higher than those reported in most studies from the USA, Europe and Israel. Compared to the incidence in Thailand, the incidence we observed in children was considerably higher, whereas the one in adults was similar to the one in that country. The results of the present study suggest that the incidence of AA in Mexico City is one of the highest worldwide, particularly in terms of the pediatric population; however, these results must be taken with caution since this study comprises only a subpopulation from Mexico City and not the entire population. Thus, further studies including a broader population, both in Mexico City and other urban and rural areas of this country, will be necessary in order to obtain better and more complete estimates of the actual incidence of AA in Mexico.     

Up-regulation of L-selectin and E-selectin in hypersensitivity pneumonitis

BACKGROUND: Selectins are adhesion molecules that contribute to leukocyte recruitment into the tissue after an injury. Hypersensitivity pneumonitis (HP) is a lymphocytic alveolitis, and we hypothesized that the overexpression of selectins could play a role in this process. PATIENTS AND MEASUREMENTS: We studied 16 patients with HP and 7 healthy control subjects (HCs). Sera and BAL selectins and tumor necrosis factor-alpha were determined by enzyme-linked immunosorbent assay, and cellular lung localization was determined by immunohistochemistry. Additionally, BAL L-selectin, and L-selectin-bearing T-lymphocytes analyzed by flow cytometry were evaluated in HP patients and in exposed but asymptomatic subjects (EAS). SETTING: Tertiary referral center and immunohistochemistry laboratory. RESULTS: Raised levels of E-selectin (mean [+/- SD], 178.9 +/- 30.5 vs 59.4 +/- 4.7 ng/mL, respectively; p < 0.001) and P-selectin (mean, 232.6 +/- 29.9 vs 67.6 +/- 14.2 ng/mL, respectively; p < 0.001) were detected in HP patient sera compared to control subjects, while L-selectin levels showed no differences between groups. Conversely, HP patients displayed a significant increase in levels of L-selectin found in BAL fluid compared with both HCs and EAS (11.0 +/- 1.7 vs 6.9 +/- 0.43 and 3.1 +/- 0.5 ng/mL, respectively; p < 0.05). The levels of E-selectin found in BAL fluid were similar in patients from both groups, and P-selectin was not detected. Percentage of CD3+CD62 L+ lymphocytes was lower in HP patients compared with EAS (2.33 +/- 0.8 vs 4.31 +/- 2.4, respectively; p = 0.05). By immunohistochemistry, L-selectin was detected in interstitial macrophages and polymorphonuclear cells, and E-selectin was detected in endothelial cells. CONCLUSION: These findings demonstrate that L-selectin and E-selectin are up-regulated during the development of HP, suggesting that they may contribute to the increased traffic of lung inflammatory cells.     

Flow-injection spectrophotometric determination of paracetamol in tablets and oral solutions

A flow injection method is proposed for the determination of paracetamol in pharmaceutical dosage forms. The method is based on the nitration of paracetamol with sodium nitrite, and the absorption of the reaction product is measured at 430 nm in alkaline medium. Unlike other colorimetric methods used for determination of paracetamol, this method does not require the use of heat. The influence of several operating parameters is studied. The method was applied to the determination of paracetamol in oral solutions and in tablets, alone or associated with caffeine. When the results were compared with those obtained by the official HPLC method (USP 24) the relative differences found were from 0.4 to 2.3%, with relative standard deviations below 1%.     

Induction of cell death by sera from patients with acute brain injury as a mechanism of production of autoantibodies

OBJECTIVE: To investigate the capacity of blood draining from the central nervous system of patients with acute brain injury to induce cell death, and to determine whether this phenomenon could be a way to induce the production of autoantibodies. METHODS: The induction of cell death of several human leukemia cell lines cultured in vitro in the presence of serum collected from the brain or the systemic circulation of patients with acute brain injury was analyzed by flow cytometry after staining with annexin V and propidium iodide. The percentages of apoptotic lymphocytes derived directly from the patients were also quantified. To investigate the mechanisms responsible for the induction of cell death, the expression of apoptosis-related molecules, as well as the effect of addition of several molecules known to interfere with apoptosis, was evaluated in the cell cultures. The presence of serum autoantibodies at the time of injury and 6 months later was studied. RESULTS: Systemic serum and, especially, serum draining from the brain lesions induced the in vitro death of the leukemia cell lines used. Moreover, there were higher percentages of ex vivo dead lymphocytes in regional blood than in systemic blood 48 hours after injury. These effects seemed to be induced by an exogenous and/or endogenous opioid, since they were blocked by the opioid antagonist, naloxone. Furthermore, such effects were mediated by an increased expression of Bax. Importantly, apoptotic Jurkat cells were bound to autoantibodies, and patients with acute brain injury produced serum autoantibodies some months after the injury. However, they did not develop a full autoimmune disease at that time. CONCLUSION: Serum factors from acute brain injuries induce cell death, both in vivo and in vitro. Apoptotic cells and, even more so, necrotic cells in acute brain injury are potential sources for autoantigen presentation that may stimulate autoimmune responses.     

Detection of human papillomavirus and relevant tumor suppressors and oncoproteins in laryngeal tumors.

PURPOSE: The mechanism of larynx oncogenesis is complex and controlled by various factors, most of them involved in cell proliferation and apoptosis. In this study, we evaluated the levels of two suppressor proteins (pRb and p53) and two oncogenic proteins (c-Myc and Bcl-2), as well as the apoptotic levels and the presence of human papillomavirus (HPV) in both tumor types. EXPERIMENTAL DESIGN: Low- or high-risk HPV viral DNA was determined by PCR and in situ PCR; the level of cellular proteins was examined by immunohistochemistry; the presence of apoptotic cells was evaluated by in situ cell death detection. RESULTS: Most laryngeal papillomatosis samples contained low-risk HPV determined by both techniques. However, 25% of laryngeal carcinoma samples were positive for HPV employing PCR or in situ PCR. In papillomatosis, pRb and p53 levels were higher than in normal larynxes, whereas laryngeal cancer presented the lowest levels. c-Myc oncogene expression was very low in normal and cancer tissues but highly increased in papillomatosis. Bcl-2 expression was low and showed no significant difference between laryngeal papillomatosis and normal larynxes. By contrast, Bcl-2 was clearly up-regulated in cancer. Normal larynx samples and those from laryngeal papillomatosis exhibited similar relatively high numbers of apoptotic cells, whereas in malignant tumors, these cells were scarce. CONCLUSION: Our results suggest that HPV is an important risk factor in papillomatosis and in some malignant larynx tumors with a strong participation of cellular genes, specifically involved in proliferation and apoptosis. In benign papillomatosis lesions but not in larynx cancer, high p53 activity might preserve the apoptosis process. In larynx cancer, low p53 levels and high bcl-2 expression may be playing an important role to block apoptosis.     

In vitro interaction between Plasmodium falciparum myosin B (PfMyoB) and myosin A tail interacting protein (MTIP)

Parasitology Research - Apicomplexan parasites, including Plasmodium falciparum, are obligate intracellular organisms that utilize a strategy termed “gliding” to move and invade host...     

Enhanced hearing in heat-activated-crimping prosthesis stapedectomy.

OBJECTIVES: Compare short-term hearing outcomes with a heat-activated-crimping versus manual-crimping stapedectomy prosthesis. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary care neurotology referral center. PATIENTS: 219 charts reviewed. INTERVENTION: Laser stapedectomy. MAIN OUTCOME MEASURES: Audiometric. METHODS: Retrospective study comparing postoperative hearing in manual-crimp prostheses stapedectomies versus heat-activated-crimp prostheses stapedectomies. RESULTS: Of the 219 patients reviewed, 94 met inclusion criteria for the study, with 47 receiving manual-crimp prosthesis and 47 receiving heat-activated-crimp prosthesis. Short-term poststapedectomy air-bone gaps, long-term air-bone gaps, long-term pure-tone averages, and long-term air-bone gap closures were significantly better for heat-activated-crimp versus manual-crimp prostheses. CONCLUSION: Heat-activated-crimping prostheses demonstrated enhanced stapedectomy hearing outcomes versus manual-crimping prostheses on short- and long-term follow-up. Three-dimensional reorientation of the heat-activated prosthesis may enhance the hearing outcome; however, theoretical nickel allergy considerations, effects of case selection, follow-up duration, possible eventual loosening of the heat-activated crimp, and long-term incus necrosis are considerations requiring continued longitudinal analysis.