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Biomedical subjects

E Gonzalez

Publications and source records attributed to E Gonzalez.

At least 19 recordsLinked to original sources
PubMed1992

A comparison of standard-dose and high-dose epinephrine in cardiac arrest outside the hospital. The Multicenter High-Dose Epinephrine Study Group.

BACKGROUND: Experimental and uncontrolled clinical evidence suggests that intravenous epinephrine in doses higher than currently recommended may improve outcome after cardiac arrest. We conducted a prospective, multicenter study comparing standard-dose epinephrine with high-dose epinephrine in the management of cardiac arrest outside the hospital. METHODS: Adult patients were enrolled in the study if they remained in ventricular fibrillation, or if they had asystole or electromechanical dissociation, at the time the first drug was to be administered to treat the cardiac arrest. Patients were randomly assigned to receive either 0.02 mg of epinephrine per kilogram of body weight (standard-dose group, 632 patients) or 0.2 mg per kilogram (high-dose group, 648 patients), both given intravenously. RESULTS: In the standard-dose group 190 patients (30 percent) had a return of spontaneous circulation, as compared with 217 patients (33 percent) in the high-dose group; 136 patients (22 percent) in the standard-dose group and 145 patients (22 percent) in the high-dose group survived to be admitted to the hospital. Twenty-six patients (4 percent) in the standard-dose group and 31 (5 percent) in the high-dose group survived to discharge from the hospital. Ninety-two percent of the patients discharged in the standard-dose group and 94 percent in the high-dose group were conscious at the time of hospital discharge. None of the differences in outcome between the groups were statistically significant. CONCLUSIONS: In this study, we were unable to demonstrate any difference in the overall rate of return of spontaneous circulation, survival to hospital admission, survival to hospital discharge, or neurologic outcome between patients treated with a standard dose of epinephrine and those treated with a high dose.

Aged↗
PubMed1992

Influence of VIP on the number of enterochromaffin and mucosal mast cells in the colon of the rat.

The possibility that VIP (Vasoactive intestinal peptide) could influence the enterochromaffin (EC) cell secretion of serotonin (5HT) and the action of VIP on the mast cell population of lamina propria were investigated in Wistar rat colon infused with a short chain fatty acid solution (sodium acetate), during a 1 h period. Under the action of an intravenous injection of synthetic porcine VIP, 14 micrograms/kg/h), the number of EC cells diminished significantly in the cecum and left colon, when compared to non-injected animals, both infused with a sodium acetate solution. At the same time, the number of mucosal mast cells in the crypts and lamina propria decreased significantly in the cecum. The postulate we put forward is that these VIP-induced changes are exerted through the stimulation of 5HT released from EC cells not only under normal physiological conditions but probably also under pathological conditions.

Animals↗
PubMed1992

Latex hypersensitivity: a new and unexpected problem.

Allergy to such latex products as surgical gloves is a growing medical problem. About 3% of hospital physicians and nurses are affected, and higher rates have been reported in surgical units. Allergic reactions may be delayed (and usually local) or immediate, with systemic derangements that are potentially fatal. Allergic patients are also vulnerable in the hospital setting.

Adult↗
PubMed1992

Granulocyte turnover in the feline intestine.

The objective of this study was to determine the turnover rate of the extravascular pool of granulocytes in different regions of the feline gastrointestinal tract. Leukocyte emigration from the vasculature was prevented over a 48-h period by repeated intravenous injections of a monoclonal antibody (MAb IB4) directed against the leukocyte adhesion glycoprotein complex CD11/CD18. Tissue-associated myeloperoxidase (MPO) activity was used to monitor the total tissue granulocyte pool at 0.5, 12, 24, and 48 h after MAb IB4 administration. The mucosal layer of the duodenum, jejunum, ileum, and colon exhibited different kinetics of granulocyte clearance, with average life-spans (t1/2) ranging between 6.9 (colon) and 10.4 h (duodenum). Granulocyte clearance rates of 0.5 x 10(6) and 2.4 x 10(6) cells/h/g tissue were estimated (from measured values of t1/2 and tissue granulocyte pool) for the small bowel and colonic mucosae, respectively. The submucosal layer of the intestine exhibited a biphasic reduction in tissue MPO activity following immunoneutralization of CD11/CD18, with an initial t1/2 < or = 0.5 h followed by a t1/2 of 36-60 h. The initial rapid decline in tissue MPO suggests that a significant fraction of granulocytes in the submucosa is localized in a readily exchangeable pool (e.g., marginated cells within the vasculature). The results of this study indicate that the average life-span of resident granulocytes varies significantly between different regions of the gastrointestinal tract, with the intestinal mucosa exhibiting a t1/2 comparable to that previously reported for circulating feline neutrophils (approximately 8 h).

Animals↗
PubMed1992

Electrochemical modification of tumor growth in mice.

We evaluated the effect of direct electrical current on large tumors in mice. Lewis lung carcinoma greater than 1 cm in the shortest dimension was treated percutaneously with 20 mA for 15 min. Separate groups were given one or more than one (two or three) percutaneous electrical treatments (PET). A third group was given sham electrical treatment, and a fourth group had surgical excision of the tumor. Animals in both PET groups survived longer and had smaller primary tumors at death compared with the sham group. PET did not alter the systemic course of the disease, judged by lung and spleen weights and by histological observation of the extent of metastatic burden in the lung. Surgery resulted in long-term survival of 17% and an increase in average survival time compared with both PET and sham treatment. PET produced rapid and polarity-dependent alterations in physiological solutions in vitro, and it is likely that similar electrochemical processes mediated the observed reduction in tumor growth. PET is potentially useful as an adjuvant modality because it reduces local tumor mass but does not alter the extent of metastasis.

Animals↗
PubMed1992

Treatment of telangiectases and other benign vascular lesions with the 577 nm pulsed dye laser.

BACKGROUND: This study was undertaken to evaluate the effectiveness and safety of the 577 nm pulsed dye laser in the treatment of various vascular lesions of the face. OBJECTIVE: Our purpose was to make observations on the effects of different variables that could affect response. METHODS: Ninety-two adults with telangiectases of the face were sequentially selected for treatment according to a protocol previously established. Evaluation consisted of visual inspection by two investigators, and before and after photographs at 2-months intervals. A few patients with other vascular lesions were also treated and reported. RESULTS: Ninety-one percent of the patients (84 of 92) showed good to excellent response after a single treatment. Recurrence occurred in 2%. Atrophy of the skin occurred in 2%. Venous lakes, pyogenic granulomas, and mucosal vascular malformations showed significant improvement. CONCLUSION: The 577 nm pulsed dye laser is effective and safe for vascular lesions of the face.

Adult↗
PubMed1992

The action of the psychoactive drug 2C-B on isolated rat thoracic aorta.

1. 2C-B [2-(4-bromo-2,5-dimethoxyphenyl)ethylamine] elicits concentration-dependent contraction of the rat thoracic aorta (apparent pD2 = 4.55). The maximal contraction (Emax) attained with 2C-B is less than that produced by either norepinephrine (NE) or serotonin (5-HT). 2. Pretreatment with either prazosin (5 x 10(-9) - 10(-8) M) or ketanserin (5 x 10(-9) - 10(-8) M) leads to decreased slopes and Emax in the 2C-B dose-response curves. 3. 2.82 x 10(-5) M 2C-B potentiates the response to low concentrations of NE; 5 x 10(-5) M 2C-B shows similar behaviour, but with reduced Emax. At 10(-6) M 2C-B acts as a competitive 5-HT antagonist; at 2.8 x 10(-5) M, however, it behaves like a non-competitive 5-HT antagonist. 4. Removal of the endothelial lining from the aortal rings only shifts the 2C-B dose-response curve to the left. 5. These results suggest that 2C-B behaves as a partial agonist toward both alpha 1-adrenergic and 5-HT2 serotonergic receptors. The endothelium only seems to act as a diffusional barrier to the drug.

Adrenergic alpha-Agonists↗
PubMed1992

D-penicillamine therapy associated with rapidly progressive glomerulonephritis.

A 55-year-old woman with advanced rheumatoid arthritis developed rapidly progressive glomerulonephritis with epithelial crescents and pulmonary hemorrhage following treatment with D-penicillamine. D-penicillamine was then withdrawn and a pulse therapy with methylprednisolone halted the progression of kidney and lung damage. We review the other cases previously reported and discuss pathogenesis and treatment of this rare condition.

Arthritis, Rheumatoid↗
PubMed1992

IL-1-like production in adriamycin-induced nephrotic syndrome in the rat.

Rats receiving a single dose of adriamycin (7.5 mg/kg) develop heavy proteinuria and morphological abnormalities similar to those observed in minimal change nephrotic syndrome in humans. A concomitance between enhanced I-a display by resident glomerular macrophages, IL-1-like cytokine secreted by whole isolated rat glomeruli and proteinuria was observed in adriamycin-injected rats during the experimental protocol. In addition, in vitro studies have shown that after stimulation with adriamycin or lipopolysaccharide (LPS) this cytokine is mainly produced by resident glomerular macrophages in culture. Although the precise mechanism of proteinuria in this model needs to be further studied, our results indicate that IL-1-like cytokine could be an important mediator implicated in the structural and functional disturbances occurring at the glomerular capillary wall level in adriamycin nephrosis.

Animals↗
PubMed1992

Paraquat poisoning in children: survival of three cases.

Five children with paraquat poisoning are presented. Three were diagnosed early, treated and survived; the other 2 arrived 1-2 days after paraquat ingestion and died subsequently from respiratory failure due to pulmonary fibrosis.

Accidents↗
PubMed1991

IgA immune aggregates stimulate platelet-activating factor and superoxide anion production by human neutrophils. A comparison with IgG aggregates.

We have examined the possibility that human polymorphonuclear cells exposed to IgA immune complexes can mediate the production of platelet-activating factor (PAF) and oxygen radicals. We found that human IgA and IgG immune aggregates stimulated, to a similar extent, PAF and O2- production by human polymorphonuclear cells (PMN) in a concentration and time dependent manner. The PAF, that was largely associated with cells, was shown to be identical to synthetic PAF, as determined by physicochemical, chromatographic and enzymatic assay. Furthermore, de novo synthesis of PAF by PMN was shown to occur by incorporation of radioactive precursors, such as [3H]acetate. The addition of normal human serum to PMN incubated with IgG aggregates resulted in a significant amount of PAF formation which was not observed with IgA aggregates. By contrast, no change was seen in PMN O2- with either aggregates. The preincubation of PMN with cytochalasin B, an inhibitor of phagocytosis, did not affect PAF and O2- production by both aggregates. The results suggest that the interaction of PMN with the IgA complexes in blood vessel walls of different tissues can result in the release of lipid mediators, such as PAF and oxygen radicals that could contribute to the inflammatory response.

Cytochalasin B↗
PubMed1991

The role of platelet-activating factor (PAF) in experimental glomerular injury.

Platelet-activating factor (PAF) is a potent autacoid that participates in inflammation and other pathophysiological processes. In this review we deal with recent evidence suggesting that PAF is a mediator that is released early during glomerular injury. PAF can be synthesized in the glomerulus by infiltrating intrinsic glomerular cells. Normal glomeruli produce PAF upon stimulation, and glomerular PAF synthesis is increased in a variety of experimental glomerulopathies. The local infusion of PAF into the renal artery of isolated blood-free kidneys induces proteinuria. PAF attracts and activates inflammatory cells. Glomerular mesangial, endothelial and epithelial cells are also targets for PAF. Therapy with specific PAF receptor antagonists has prevented or reduced proteinuria and improved glomerular inflammation in several experimental models of proliferative glomerulonephritis and minimal change nephrosis. However, the beneficial effect of administration of PAF antagonists once proteinuria is fully developed has been minimal. PAF may also play a role in the recruitment of inflammatory interstitial cells.

Animals↗
PubMed1991

Use of an in vitro model to assess the effects of APF gel treatment on the staining potential of dental porcelain.

Porcelains and resin composites exposed to acidulated phosphate fluorides (APF) have been reported to result in increased roughness, loss of weight, and loss of specular reflectance (gloss). Six samples of five commercial porcelains were subjected to five four-minute treatments with APF gels. Samples were then subjected to a nine-day cyclic staining procedure that utilized a tea, coffee, and mucin mixture. Changes in reflectance were then measured by means of a Minolta Chromameter (CR121) and converted to CIE L* a* b* values at illuminant D65 against a white background. delta L*, delta a*, delta b*, and delta E values were calculated. There was a substantial decrease in the L* value (lightness) for all porcelains. The average L* value for APF-treated and then stained porcelains was 43.6, for the stained-untreated samples, 48.2, and for untreated-unstained porcelain, 53.5. For three of the five porcelains, the differences in L* between treated and untreated stained porcelains were statistically significant. Changes in a* and b* values were also found to be consistent with but not as large as the changes in L*.

Acidulated Phosphate Fluoride↗
PubMed1991

Comparison of minimal phototoxic dose and skin type for determining initial UVA dose in oral liquid methoxsalen photochemotherapy for the treatment of psoriasis.

Twenty-five patients with extensive psoriasis were randomly assigned into one of three groups, each receiving 0.5 mg/kg of oral liquid methoxsalen photochemotherapy followed 1 h later by exposure to long-wave ultraviolet light (UVA). The sole difference between the three groups was the method used to determine the initial UVA dose, which was either based on skin type, 25% of the minimal phototoxic dose (MPD), or 50% of the MPD. All patients were treated in the Phototherapy Unit at the Massachusetts General Hospital. Data were obtained until reaching the endpoint of clearance. At clearance, the results of the number of treatments required to clear, final UVA dose, cumulative UVA dose, and side effects were tabulated, compared, and analyzed for each of the three groups. The 25% and 50% MPD groups required a mean of 15.0 +/- 1.7 and 13.4 +/- 1.9 treatments to clear, respectively, as compared to the skin type group, which needed an average of 17.6 +/- 2.5 treatments. The mean final UVA dose was 7.4 +/- 0.9 J/cm2 and 8.4 +/- 1.4 J/cm2 for the 25% and 50% MPD groups, respectively, in contrast to 11.6 +/- 1.4 J/cm2 for the skin type group. The mean cumulative UVA dose at clearance for the 25% and 50% MPD groups was 79 +/- 16 J/cm2 and 87 +/- 27 J/cm2, respectively, versus 136 +/- 30 J/cm2 for the skin type group. The comparisons between the individual MPD groups and the skin type group did not achieve statistical significance with the exception of a marginally significant difference in final dose between the skin type group and the 25% MPD group (p = 0.06). However, the results of the two MPD groups were then pooled and the mean final (7.9 +/- 0.8 J/cm2) and cumulative (83 +/- 15 J/cm2) UVA doses were significantly (p = 0.04) and marginally significantly (p = 0.07) lower than the respective means of the skin type group. The number of treatments to clear, although lower in the pooled MPD groups (14.2 +/- 1.3) than in the skin type group, did not attain statistical significance (p = 0.19). Our data suggest that the MPD measurement may be superior to the skin-typing system when calculating the initial UVA dose in oral liquid methoxsalen photochemotherapy for the treatment of psoriasis.

Adult↗
PubMed1991

Intracellular cytosolic free calcium concentration in the macula densa and in ascending limb cells at different luminal concentrations of sodium chloride and with added furosemide.

The juxtaglomerular apparatus fulfils several important regulatory functions in the kidney, such as tubuloglomerular feedback (TGF) control and control of renin release. The macula densa (MD) cells sense the fluid load by perceiving the distal NaCl concentration via a Na-K-2Cl cotransport system in the luminal cell membrane. It has been proposed that macula densa cell activation may involve changes in intracellular cytosolic free calcium concentration ([Ca2+]i), as one link in the chain of events activating TGF or releasing renin. We therefore investigated the changes in the intracellular calcium concentrations with fura-2, using a video system, in macula densa cells, and compared them with the changes in the corresponding concentrations in the ascending limb of the loop of Henle (c-TAL). The results show that our technique for analysing intracellular cytosolic free calcium in isolated perfused tubules is valid for this purpose, and the Kd value obtained was similar to that found by Grynkiewicz et al. (1985). The intracellular cytosolic free calcium concentration was about 90 nM both in the macula densa and c-TAL cells, and the macula densa cell intracellular cytosolic free calcium concentration increased by about 20 nM when the tubular lumen was perfused with Na and Cl at low concentrations. No significant changes were noted when furosemide was added to the perfusion solutions. We consider it hardly likely that this small change in intracellular cytosolic free calcium concentration can be entirely responsible for full activation of renin release or full inactivation of the TGF control mechanism. It would seem that the signal transmission from the macula densa cells could occur by other routes than through activation of intracellular cytosolic free calcium concentration.

Animals↗