Search PubMed⌕ Search

Biomedical subjects

O Martinez

Publications and source records attributed to O Martinez.

At least 55 records · Page 3Linked to original sources
PubMed1992

Effects of pentoxifylline on the cardiovascular manifestations of group B streptococcal sepsis in the piglet.

Pentoxifylline (PTXF) is a methylxanthine that modifies leukocyte function and inhibits cytokine release. To evaluate its effects on the cardiovascular manifestations of sepsis secondary to group B streptococci, 14 anesthetized, mechanically ventilated piglets were studied over a 240-min period. Animals were randomly assigned to a treatment group that received a PTXF bolus (20 mg/kg) followed by a continuous infusion of 5 mg/kg/h before and during group B streptococci (1 x 10(8) colony forming units/kg/min) administration and a control group that received saline as a placebo. Comparison of the hemodynamic measurements and arterial blood gases during the first 90 min of PTXF treatment with those of the control group resulted in the following 90 min values: systemic arterial blood pressure was significantly higher in the PTXF group (89 +/- 10 versus 56 +/- 30 mm Hg; p less than 0.005) as was cardiac output (0.18 +/- 0.04 versus 0.10 +/- 0.07 L/kg/min; p less than 0.005). Pulmonary vascular resistance remained lower in the PTXF-treated animals (135 +/- 117 versus 248 +/- 119 mm Hg/L/min/kg; p less than 0.001), and these animals were less acidotic as measured by pH (7.07 +/- 0.2 versus 7.31 +/- 0.1; p less than 0.05) and base deficit (-15 +/- 9 versus -5 +/- 2 mmol/L; p less than 0.05). Median survival time was significantly longer in the PTXF group (210 versus 90 min; p less than 0.002). These data demonstrate that PTXF can ameliorate some of the deleterious hemodynamic manifestations of group B streptococci sepsis and result in improved survival in a young animal model.

Acid-Base Equilibrium↗
PubMed1991

Hemodynamic effects of conventional and high frequency oscillatory ventilation in normal and septic piglets.

The cardiovascular effects of high frequency oscillation (HFO) and conventional ventilation (CMV) were evaluated in 10 piglets prior to and during an infusion of group B streptococci (GBS). Animals were randomized to begin ventilation with either HFO or CMV. Arterial blood gases, cardiac output (CO), and pulmonary artery (Ppa), pulmonary wedge (Ppw) and arterial blood pressures were measured. These values were recorded at a mean airway pressure (MAP) of 2 cm H2O for both modes of ventilation after which a continuous infusion of GBS (4 X 10(7) CFU/kg/min) was begun. MAP was increased in both ventilators in the following sequence: 4, 8 and 12 cm H2O. Prior to GBS infusion, HFO was associated with small but significant changes in hemodynamic parameters when compared to CMV for the following: Ppa (15 +/- 4 vs. 13 +/- 4.0 mm Hg; p less than 0.03), Ppw (3 +/- 1 vs. 2 +/- 1 mm Hg; p less than 0.02), and CO (0.24 +/- 0.08 vs. 0.25 +/- 0.09 l/min/kg; p less than 0.05). Similar statistically significant increases in Ppa (p less than 0.005) and Ppw (p less than 0.0001), and decrease in CO (p less than 0.007) were present during GBS infusion when animals were ventilated with HFO, irrespective of the MAP used. Our results suggest that the use of HFO in both normal piglets and those receiving an infusion of GBS results in mild but consistent impairment in cardiovascular function compared to CMV. In summary, these data demonstrate that HFO has no beneficial effect compared to CMV at similar MAP in the management of the septic piglet model and may in fact further compromise the animal's hemodynamic status.

Animals↗
PubMed1990

Recombinant IL-4 inhibits IL-6 synthesis by adherent peripheral blood cells in vitro.

IL-4 has been shown to participate in interregulatory networks with other cytokines including IL-2, IFN-gamma, IL-1 beta, and TNF-alpha. The ability of recombinant IL-4 (rIL-4) to modulate the synthesis and release of IL-6 was investigated in vitro. LPS-stimulated adherent cells (AC) from human peripheral blood secreted IL-6 as determined by ELISA and bioassay with the B9 hybridoma cell line. The secretion of IL-6 peaked between 12-16 h after LPS stimulation. The addition of rIL-4 inhibited LPS-induced IL-6 production measured at 8 h. The inhibitory effect of rIL-4 on IL-6 secretion was dose-dependent and occurred at doses as low as 0.001 U/ml (0.01 pg/ml). Recombinant IL-4 was added to the cultures for various periods and removed by aspiration of the medium and washing the cells. The subsequent LPS-induction of IL-6 secretion was reduced in cultures exposed to rIL-4 for as little as 5 minutes indicating that the effect of rIL-4 on the monocytes was rapid and irreversible. Northern blot analysis revealed that the effect of rIL4 on LPS-induced production of IL-6 by AC occurred at least in part at the level of transcription. In contrast, PMA-induced IL-6 gene transcription was not affected by rIL-4. These findings indicate that rIL-4 can regulate the synthesis of IL-6 by adherent peripheral blood mononuclear cells.

Acute-Phase Reaction↗
PubMed1990

Atropine: effects on glucose metabolism.

We have employed the primed constant infusion technique to investigate the metabolic effects of the organophosphate antidote, atropine, on glucose homeostasis in rats. This method utilizes the radioisotopes 6-3H-glucose to measure production and uptake and U-14C-glucose to measure oxidation. Our data indicate that glucose production significantly (p less than 0.05) increased (24.0 +/- 2.0 vs. 30.9 +/- 2.6 mumoles.kg-1.min-1) following atropine administration. The elevated rate of glucose turnover was associated with concomitant increases in glucose oxidation (8.3 +/- 0.6 vs. 12.0 +/- 0.8, mumoles.kg-1.min-1), the percent of glucose uptake oxidized (37.2 +/- 2.0 vs. 44.6 +/- 2.6), and the percent carbon dioxide produced from glucose (8.4 +/- 0.7 vs. 12.0 +/- 1.8). Presumably, these glucokinetic changes were mediated by elevated plasma catecholamines (Epi: 166 +/- 19 vs. 271 +/- 50 pg/ml; Norepi: 262 +/- 24 vs. 525 +/- 63 pg/ml, p less than 0.05) since other glucoregulatory hormones (insulin, glucagon, and corticosterone) were not significantly affected by atropine administration. In addition, there was no change in VO2 associated with atropine administration. These data indicate that atropine enhances glucose production and utilization; such effects could be ergogenic during exercise in thermoneutral conditions.

Animals↗
PubMed1989

[Clinical and paraclinical differences between chronic Chagas' cardiomyopathy and primary dilated cardiomyopathies].

With the purpose of establishing clinical and paraclinical differences among chronic chagasic (MCh) and primary dilated cardiomyopathies (MCDP), 96 MCh and 104 MCDP patients with abnormal ECG were submitted to a study protocol which included clinical history, routine laboratory serology for Chagas' diseases, resting ECG, Chest-X-rays, and cardiac catheterisation. Patients with congestive heart failure (CHF) had common clinical and para-clinical findings. However, chagasic patients without CHF showed more prevalence of RBBB and LAH, complex ventricular arrhythmias and more left ventricular dilation while primary dilated cardiomyopathy patients with CHF had predominantly LBBB, simple ventricular arrhythmias, atrial fibrillation and less LV dilation than MCh patients. In order to establish the prognostic value of these findings and response to modern medical therapy, prospective studies on these two groups of patients are needed.

Cardiomyopathy, Dilated↗
PubMed1988

The role of leukotrienes in the late hemodynamic manifestations of group B streptococcal sepsis in piglets.

In order to evaluate the role of leukotrienes in group B streptococcal (GBS) sepsis we studied the effect of a leukotriene receptor antagonist, FPL 57231, on the late hemodynamic changes occurring secondary to an infusion of live GBS. Paralyzed, mechanically ventilated piglets received a continuous intravenous infusion of bacteria (5 x 10(7) org/kg/min) while systemic arterial (Psa) and pulmonary artery pressures (Ppa) were measured. To separate the effects of the lipoxygenase products of arachidonic acid from those of the cyclooxygenase by-products, animals in control and treatment groups received indomethacin, a cyclooxygenase blocking agent, 15 min after the infusion of GBS was begun. In addition to GBS and indomethacin, treatment animals received a 30 min infusion of FPL 57231 starting 120 min after the bacterial infusion was begun. All study animals responded to bacteria within 15 min with marked elevation in pulmonary artery pressure (X +/- SD) (12 +/- 3 to 49 +/- 5 mmHg; p less than .01), and a decline in PaO2 (84 +/- 9 to 49 +/- 5 mmHg; p less than .01) and cardiac output (0.29 +/- 0.04 to 0.18 +/- .07 liter/min/kg; p less than .01). These changes were reversed by indomethacin. Subsequent values remained relatively stable until approximately 90 min when a gradual decrease in cardiac output (CO) and PaO2, and an increase in Ppa, and calculated systemic (SVR) and pulmonary (PVR) vascular resistances occurred. After the initial increase in TxB2 and 6-keto-PGF1 alpha, indomethacin treatment resulted in return of these values to baseline with no further increase throughout the study period.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗
PubMed1986

Converting Sendai virus into a specific fusogen whose cell target can be selected.

Covalent intermolecular hybrids of Fab anti-hemagglutinin-neuraminidase (HN) monoclonal antibody and avidin were prepared and characterized. These conjugates were used to block and redirect the fusion activity of Sendai virus (SV). After incubation of SV with Fab anti-HN: avidin conjugate on ice for 1-2 h, the SV fused only those P815 or BW5147 cells which were labeled with biotin-modified anti-cell surface immunoglobulin. The levels of cell-cell fusion obtained were at least as high as those achieved with unmodified SV and unlabeled P815 or BW5147 cells. These results demonstrate that it is possible to block the normal agglutinating activity of the HN molecules of SV and to introduce a new cell recognition feature without negating the fusogenic potential of the virus. Such an approach may be useful in harnessing the fusion activity of SV to a targeted delivery system for microinjection of macromolecules into selected cell populations.

Agglutination↗
PubMed1986

Simultaneous determination of fluid shifts during thermal stress in a small-animal model.

We have developed methodology to simultaneously measure fluid redistribution among the major compartments during moderate and severe hypohydration. Total body water (TBW) was determined using tritiated water, extracellular fluid volume (ECF) was measured using a single-injection [14C]inulin technique, and plasma volume (PV) was determined by indocyanine green dye dilution. Moderate (10% decrease in body wt) and severe (15%) hypohydration resulted in significant losses in TBW, ECF, and PV. Plasma volume was decreased by approximately 25% in both groups, and other fluid compartments were differentially affected. For example, the moderately dehydrated group maintained PV by shifting fluid from the interstitial fluid volume (ISF) compartment while preserving the intracellular fluid volume (ICF); conversely, the severely dehydrated group maintained PV by redistributing fluid from both the ISF and ICF compartments. The data indicated that the initial response to fluid loss was the movement of fluid from the ISF pool to sustain both PV and ICF. In severely hypohydrated rats, PV was maintained at the expense of ICF. These experiments indicated that PV and ICF were maximally protected, probably to preserve the integrity of the cardiovascular system and to minimize organ injury.

Animals↗
PubMed1986

A prospective randomized study of moxalactam versus gentamicin and clindamycin in penetrating abdominal trauma.

We conducted a randomized, prospective study of moxalactam versus gentamicin plus clindamycin in 42 patients with penetrating abdominal trauma. Patients were randomized to receive intravenously either 2 grams of moxalactam every 12 hours or 80 milligrams of gentamicin every eight hours and 600 milligrams of clindamycin every six hours. Antibiotics were administered preoperatively and continued for a minimum of five days if hollow viscus injury occurred. For those without hollow viscus injury, only those patients receiving a minimum of three days of antibiotics were evaluated. A single intramuscular dose of 10 milligrams of vitamin K was also administered to all patients in the moxalactam group. There were 39 males and three females with a mean age of 33 years. Twenty patients received moxalactam and 22 received gentamicin plus clindamycin. The mechanism of injury was gunshot wound in 32 patients and stab wounds in ten patients. Eight patients in each group sustained injuries to the small intestine or colon, or both. The mean injury severity score was 22.6 and 21.2 in the single and double antibiotic regimen, respectively. The mean duration of antibiotic therapy was 5.8 and 7.0 days in the single and double antibiotic group, respectively. No infectious complications occurred in the moxalactam group whereas five infections occurred in four patients in the gentamicin plus clindamycin group (p less than 0.05). These infections included one intra-abdominal abscess, two wound infections and two episodes of necrotizing fasciitis of the wound and abdominal wall. There were no complications attributable to moxalactam therapy. The over-all mortality rate was zero per cent. The total pharmacy cost of a five day course of moxalactam plus a single dose of vitamin K is $204.67 compared with $226.00 for a similar course of gentamicin plus clindamycin. We conclude that: moxalactam is at least, if not more, effective in preventing infectious complications after penetrating abdominal trauma compared with gentamicin plus clindamycin; moxalactam is safe in the doses used when combined with vitamin K, and 3, moxalactam is more cost-effective than gentamicin plus clindamycin dual antibiotic therapy.

Abdominal Injuries↗
PubMed1985

Phytobezoar from the stem ("quiote") of the cactus Agave americana: report of case.

Agave americana is a cactus growing abundantly in Mexico. Its cooked stem ("quiote") yields by mastication a sweet juice which is swallowed, while the fibers ("bagazo") are spit out. That is the way Mexicans are taught to chew quiote since their early childhood, and it accounts for the rarity of bezoars from this origin. One of such cases is reported herein.

Bezoars↗
PubMed1979

Elongation factor Tu-induced conformational changes of ribosomes detected by iodination.

The effect of elongation factor (EF) Tu, bound to the ribosome with the help of poly(uridylic) acid, Phe-tRNA and guanyl-5'-yl methylene diphosphonate, on the conformation and/or chemical environment of ribosomal proteins has been examined using, as a probe, protein iodination. Ribosomes complexed only with poly(uridylic acid) and Phe-tRNA have been used as a control. EF-Tu on the ribosome significantly increases the iodination of proteins S7, S10 and L3 and decreases that of S21 and L18.

Lactoperoxidase↗
PubMed1977

Effect of oral contraceptives on blood folate levels in pregnancy.

An investigation was carried out to assess residual effects of oral contraceptives on the folate status of pregnant women who had discontinued intake of these drugs within six months of conception. The sample population of middle class women consisted of users and nonusers of oral contraceptives of similar age groups. Subgroups were those studied initially during the summer (May to July) or winter (October to January). Red blood cell folate values showed seasonal variability and were lower in the winter months. Oral contraceptive users had lower plasma and red blood cell folate values than did the respective control subjects. Red blood cell folate values were more affected by previous drug use in the winter group than in the summer group. Dietary folate was found to have a significant effect on plasma and red cell folate; such for any one level of intake, blood folate values were significantly lower in oral contraceptive users.

Adult↗