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Biomedical subjects

L A Martinez

Publications and source records attributed to L A Martinez.

13 recordsLinked to original sources
PubMed1989

Benzodiazepines identified by capillary gas chromatography-mass spectrometry, with specific ion screening used to detect benzophenone derivatives.

We developed algorithms for confirmation and identification of benzodiazepines and their metabolites, initially detected in urine samples by enzyme-multiplied immunoassay (EMIT). These algorithms are based on the pattern of benzophenone derivatives of benzodiazepines obtained by gas chromatography-mass spectrometry (GC-MS) with use of a modified specific ion selection mode. Benzophenone derivatives were produced by acid hydrolysis of urine samples containing benzodiazepines and (or) their metabolites. We present mass spectra of the newer benzodiazepines--alprazolam, midazolam, and triazolam--and we determined the detection limit (0.2 mg/L) for these drugs as measured with the EMIT d.a.u. benzodiazepine assay and the ETS instrument (both from Syva Co.). We conclude that these algorithms are useful mostly in forensic toxicology in which unequivocal identification of benzodiazepines is the desired goal.

Alprazolam↗
PubMed1988

Cardiovascular effects of leukotrienes in the bullfrog.

While the cardiovascular effects of the sulfidopeptide leukotrienes (LTs) have been well studied in mammals, their effects are not well known in lower vertebrates. American bullfrogs (Rana catesbeiana) were cannulated in the right sciatic artery and left sciatic vein. In some studies an additional ventricular cannula was implanted. LTC4, LTD4, and LTE4 were compared for their cardiovascular actions by infusion via the sciatic vein into the unanesthetized animals. While all three leukotrienes decreased mean arterial pressure (MAP) and increased heart rate (HR), LTC4 was found to be more potent than the other leukotrienes. In bullfrogs with ventricular cannulae to measure ventricular pressure (VP) and its derivative (+ dP/dt), LTC4 had negative inotropic effects which were blunted by indomethacin (4 mg/kg-bw). 3H-LTC4 metabolism studies were carried out using blood and plasma to examine conversion to other products. Following incubation for 12 min and extraction by C18 Sep-Pak cartridges, samples were analyzed by high performance liquid chromatography. In whole blood, but not in plasma, 3H-LTC4 was rapidly converted to a compound with the retention time of the LTD4 standard. Little conversion to LTE4 was observed within the time course of the experiment. The data suggest that cardiovascular effects of LTC4 may be greater than those observed, since LTC4 is rapidly metabolized to a less active compound. The effects of LTC4 may, in part, be due to stimulation of synthesis of cyclooxygenase metabolites. The ability to record the effects of leukotrienes uncomplicated by effects on coronary arteries make the bullfrog an excellent model for comparative studies on the cardiovascular effects of leukotrienes.

Animals↗
PubMed1986

Type II cell proliferation related to migration of inflammatory cells into the lung.

Enhanced proliferation of epithelial cells in the lung is usually associated with some form of cellular injury. However, increased epithelial cell proliferation has also been observed in the absence of morphological signs of cellular injury. The nature of the stimuli to cell proliferation in the absence of cell injury is not clear. We hypothesized that one stimulus to epithelial cell proliferation in the absence of morphological injury to lung cells was the migration of inflammatory cells through the epithelium from the vasculature. This hypothesis was tested by comparing proliferation in the lungs of normal mice with that of white blood cell (WBC)-depleted mice when migration of WBC was stimulated by carbon instillation. White blood cell depletion in mice was accomplished with injections of 89SrCl2 (irradiated group). Sixteen days later, when WBC levels were reduced by about 64%, 4 mg colloidal carbon was instilled intratracheally into both normal and irradiated mice. At intervals of 1 through 4, 7, and 14 days after carbon instillation, four mice in each group were given ip tritiated thymidine and killed 1 hr later, and the lungs lavaged and prepared for electron microscopy and light microscope autoradiography. Analysis of lavage fluid revealed about 69% fewer cells in the irradiated mice compared to the normal mice at 1 day. There was no electron microscopic evidence of injury to the alveolar epithelium in either the normal or irradiated mice but there was increased proliferation of Type II cells. The proliferative response of Type II cells was 100 and 300% greater in the normal lung compared to irradiated mice at 3 and 4 days after carbon instillation, respectively. These data support the hypothesis that epithelial cell proliferation in the lung, in the absence of cellular injury, is related to the migration of WBC into the lung.

Animals↗
PubMed1986

Enhanced proliferation of pulmonary alveolar macrophages after carbon instillation in mice depleted of blood monocytes by strontium-89.

The purpose of this study was to evaluate the potential of pulmonary alveolar macrophage (PAM) and interstitial cell division as local sources of PAM in the absence of migratory monocytes. Male B6C3F1 mice were treated with Strontium-89 to deplete the levels of circulating monocytes. Normal and irradiated mice were then instilled intratracheally with carbon particles to increase the demand for PAM. Dividing cells were labeled with tritiated thymidine. The proportion of tritiated thymidine-labeled cells was then determined in lavaged PAM and in IC of lung tissue as an indicator of the proliferative response associated with the demand for increased number of PAM. It was hypothesized that, in the absence of circulating monocytes as a source of PAM, cell division of the local source of PAM would be greater in the monocyte-depleted mice than in the normal mice. It was found that proliferation of lavaged PAM was 112% greater in the monocyte-depleted mice, whereas proliferation of IC in the monocyte-depleted mice was 45% less than that in the normal mice. It was concluded that: cell proliferation of PAM is a significant local source of PAM, and division of cells in the interstitium could not be evaluated as a source of PAM due to the heterogenous nature of the cell types which comprise this population of cells. This study established that cell division of "free" PAM can be a significant local source of PAM and raises questions concerning the nature of the interstitial source of PAM.

Animals↗
PubMed1985

Topical ketoconazole for fungal keratitis.

Six patients (five men and one woman, 19 to 57 years old) with laboratory-proven fungal corneal infections were successfully treated with topical ketoconazole, a synthetic imidazole derivative. No signs of progression of the corneal infection were seen after the antifungal therapy was initiated. The clinical signs of corneal infection disappeared after three (Aspergillus infections) to seven weeks (Fusarium infections) of ketoconazole therapy. In all cases, posttreatment visual acuities were better than pretreatment visual acuities. No significant biomicroscopic signs of ocular surface toxicity were noted.

Administration, Topical↗
PubMed1983

Metronidazole in the prophylaxis of anaerobic infections in gynecologic surgery.

A double-blind study was initiated in January 1978 to determine the effectiveness of the prophylactic use of metronidazole, either orally or intravenously, in patients undergoing elective gynecologic surgery. A total of 121 women were evaluated; 42 women received oral metronidazole, 40 women intravenous metronidazole, and 39 women placebo therapy. Evidence of postoperative infection was present in 20% of patients treated with placebo, whereas in the active drug groups the incidence of infection was 12%. Blood levels of metronidazole during the operations had a mean value of 22.2 and 17.9 micrograms/ml for patients receiving intravenous and oral metronidazole, respectively. Preoperative cultures for anaerobic organisms revealed an incidence range of 23% to 45% for the three study groups. The incidence of positive anaerobic cultures declined dramatically by the second postoperative day for patients receiving intravenous and oral metronidazole, In the placebo group, the incidence was not significantly different from that in the preoperative period. This preliminary study revealed that the incidence of postoperative infections subsequent to gynecologic surgery can be reduced significantly through the use of prophylactic metronidazole.

Cesarean Section↗