LC-MS/MS quantitation of plasma progesterone in cattle.

Quantitation of progesterone (P(4)) in biological fluids is often performed by radioimmunoassay (RIA), whereas liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) has been used much less often. Due to its autoconfirmatory nature, LC-MS/MS greatly minimizes false positives and interference. Herein we report and compare with RIA an optimized LC-MS/MS method for rapid, efficient, and cost-effective quantitation of P(4) in plasma of cattle with no sample derivatization. The quantitation of plasma P(4) released from three nonbiodegradable, commercial, intravaginal P(4)-releasing devices (IPRD) over 192 h in six ovariectomized cows was compared in a pairwise study as a test case. Both techniques showed similar P(4) kinetics (P > 0.05) whereas results of P(4) quantitation by RIA were consistently higher compared with LC-MS/MS (P < 0.05) due to interference and matrix effects. The LC-MS/MS method was validated according to the recommended analytical standards and displayed P(4) limits of detection (LOD) and quantitation (LOQ) of 0.08 and a 0.25 ng/mL, respectively. The high selective LC-MS/MS method proposed herein for P(4) quantitation eliminates the risks associated with radioactive handling; it also requires no sample derivatization, which is a common requirement for LC-MS/MS quantitation of steroid hormones. Its application to multisteroid assays is also viable, and it is envisaged that it may provide a gold standard technique for hormone quantitation in animal reproductive science studies.

Influence of spontaneous calcium events on cell-cycle progression in embryonal carcinoma and adult stem cells.

Spontaneous Ca(2+) events have been observed in diverse stem cell lines, including carcinoma and mesenchymal stem cells. Interestingly, during cell cycle progression, cells exhibit Ca(2+) transients during the G(1) to S transition, suggesting that these oscillations may play a role in cell cycle progression. We aimed to study the influence of promoting and blocking calcium oscillations in cell proliferation and cell cycle progression, both in neural progenitor and undifferentiated cells. We also identified which calcium stores are required for maintaining these oscillations. Both in neural progenitor and undifferentiated cells calcium oscillations were restricted to the G1/S transition, suggesting a role for these events in progression of the cell cycle. Maintenance of the oscillations required calcium influx only through inositol 1,4,5-triphosphate receptors (IP(3)Rs) and L-type channels in undifferentiated cells, while neural progenitor cells also utilized ryanodine-sensitive stores. Interestingly, promoting calcium oscillations through IP(3)R agonists increased both proliferation and levels of cell cycle regulators such as cyclins A and E. Conversely, blocking calcium events with IP(3)R antagonists had the opposite effect in both undifferentiated and neural progenitor cells. This suggests that calcium events created by IP(3)Rs may be involved in cell cycle progression and proliferation, possibly due to regulation of cyclin levels, both in undifferentiated cells and in neural progenitor cells.

[Otitis medias with effusion: association with the Eustachian tube dysfunction and adenoiditis. The case of the Central Hospital of Maputo]. / Otitis medias con derrame: asociación con el síndrome de disfunción tubárica y las adenoiditis. El caso del Hospital Central de Maputo.

INTRODUCTION: Although the aetiology of otitis media is known to be multifactorial, adenoids infections and Eustachian tube dysfunction, have been frequently associated with the incidence of middle-ear effusion. Middle-ear effusion cases are frequent in Maputo, Mozambique, and very often insertion of tympanostomy tubes and adenoidectomy alone or with amigdalectomy have been used to treat these cases and to prevent further episodes. The objective of this study is to describe the association of these factors with otitis medias with effusion in patients that visit the Otorrinolaringology department (ENT) at the Central Hospital of Maputo (HCM), as well as to describe the clinical and epidemiological profile of these patients. PATIENTS AND METHODS: A cross sectional study was conducted. 4157 clinical files of all patients who made their first visit to the ENT department at the HCM, with otitis media during a period of 4 years (1995 to 1998). RESULTS: 23.3% of patients who visited the ORL service of Maputo with otitis media, are children under 3 years; the major proportion of otitis media with effusion was observed in children aged from 3 to 7 years old (49.2%). In boys under, otitis media with effusion is strongly associated with the history of adenoiditis and/or Eustachian tube dysfunction (OR=9.53) and in older patients (OR=12.26). CONCLUSION: The proportion of otitis media with effusion increases more evidently in patients with disfuntion tube syndrome. Other factor that can be important in patients under seven, is the presence of adenoiditis.

Prevalence of HIV-1 and HIV-2/HTLV-IV infections in Luanda and Cabinda, Angola.

A seroepidemiological study of human immune deficiency virus type 1 (HIV-1) and HIV-2/human T-lymphotropic virus type IV (HIV-2/HTLV-IV) infections was performed in Angola in October 1986. Until then five cases of acquired immune deficiency syndrome (AIDS) had been registered in Angola. During this study, another three cases with clinical AIDS were found and confirmed by HIV-1 serology. A total of 1,215 sera from groups of healthy persons and patients were tested for HIV-1 and HIV-2/HTLV-IV antibodies by enzyme-linked immunosorbent assays (ELISA). Sera positive by ELISA were also tested by Western blot (WB) analysis. In Luanda, the capital, HIV-1 antibodies were demonstrated in 0.4% (2/452) of male blood donors, in 0.3% (1/357) of pregnant women, in 1% (1/100) of tuberculosis patients, in 4% (4/94) of patients at medical wards, and in none of 22 women hospitalized with pelvic infections. In the Cabinda province, 11% (4/38) of postnatal women at a maternity ward were found to be HIV-1 seropositive, but only 2% (1/55) of other hospitalized patients and none of 32 male blood donors or 59 healthy persons in a village on the border to Zaire. Specific antibodies to HIV-2/HTLV-IV were not found in any of the sera. However, 16 out of 17 HIV-1 positive sera cross-reacted with HIV-2/HTLV-IV core proteins by WB. In October 1987, 280 of the blood donors from Luanda were retested for HIV-1 antibodies and one of them was found to have seroconverted during the previous year.(ABSTRACT TRUNCATED AT 250 WORDS)