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Biomedical subjects

M Palma

Publications and source records attributed to M Palma.

At least 37 records · Page 2Linked to original sources
PubMed1999

Fractional extraction of compounds from grape seeds by supercritical fluid extraction and analysis for antimicrobial and agrochemical activities.

White grape seeds were subjected to sequential supercritical fluid extraction. By increasing the polarity of the supercritical fluid using methanol as a modifier of CO(2), it was possible to fractionate the extracted compounds. Two fractions were obtained; the first, which was obtained with pure CO(2), contained mainly fatty acids, aliphatic aldehydes, and sterols. The second fraction, obtained with methanol-modified CO(2), had phenolic compounds, mainly catechin, epicatechin, and gallic acid. The fractions were bioassayed. Antimicrobial activities were checked on human pathogens, and a high degree of activity was obtained with the lipophilic fraction. Agrochemical activities on phytopathogenic fungi and activities on the etiolated wheat coleoptile bioassay were also checked. The more polar fraction was active in the latter bioassay.

Bacteria↗
PubMed1999

Functional studies of a fibrinogen binding protein from Staphylococcus epidermidis.

A gene encoding a fibrinogen binding protein from Staphylococcus epidermidis was previously cloned, and the nucleotide sequence was determined. A portion of the gene encompassing the fibrinogen binding domain has now been subcloned in an expression-fusion vector. The fusion protein can bind to fibrinogen in a capture enzyme-linked immunosorbent assay and can be purified by fibrinogen affinity chromatography. This protein can completely inhibit the adherence of S. epidermidis to immobilized fibrinogen, suggesting that the adherence of S. epidermidis to fibrinogen is mainly due to this protein. Antibodies against this fibrinogen binding protein were also found to efficiently block the adherence of S. epidermidis to immobilized fibrinogen. Despite homology with clumping factors A and B from S. aureus (cell surface-associated proteins binding to fibrinogen), binding involved the beta chain of fibrinogen rather than the gamma chain, as in clumping factor A.

Animals↗
PubMed1999

Adherence of Staphylococcus aureus is enhanced by an endogenous secreted protein with broad binding activity.

A novel mechanism for enhancement of adherence of Staphylococcus aureus to host components is described. A secreted protein, Eap (extracellular adherence protein), was purified from the supernatant of S. aureus Newman and found to be able to bind to at least seven plasma proteins, e.g., fibronectin, the alpha-chain of fibrinogen, and prothrombin, and to the surface of S. aureus. Eap bound much less to cells of Staphylococcus epidermidis, Streptococcus mutans, or Escherichia coli. The protein can form oligomeric forms and is able to cause agglutination of S. aureus. Binding of S. aureus to fibroblasts and epithelial cells was significantly enhanced by addition of Eap, presumably due to its affinity both for plasma proteins on the cells and for the bacteria.

Bacterial Adhesion↗
PubMed1999

[Immunoglobulin rearrangement in the differential diagnosis of primary gastric lymphoma].

BACKGROUND: The traditional methods to distinguish Chronic Follicular Gastritis and Primary Gastric Lymphoma do not allow an adequate definitive diagnosis in a significant number of cases. The molecular Biology diagnostic methods are based on the rearrangement of immunoglobulin genes. The polymerase chain reaction (PCR) specifically amplifies this rearrangement and allows molecular analysis of minimal tissue samples obtained with endoscopical biopsies. AIM: To test the usefulness of this PCR method in the differential diagnosis between Chronic Follicular Gastritis and Primary Gastric Lymphoma. MATERIAL AND METHODS: We analyzed the endoscopical biopsies of six Chronic Follicular Gastritis cases and eight surgically treated Primary Gastric Lymphoma cases, six with the correct diagnosis in the endoscopical biopsies and two with a diagnosis of Chronic Follicular Gastritis. RESULTS: A policlonal immunoglobulin rearrangement was found in the six cases with Chronic Follicular Gastritis. A monoclonal arrangement was found in 5 of 6 biopsies with the diagnosis of Primary Gastric Lymphoma. The same monoclonal rearrangement was observed in the two biopsies incorrectly diagnosed as Chronic Follicular Gastritis. CONCLUSIONS: PCR analysis of immunoglobulin rearrangement is a useful method in the differential diagnosis between Chronic Follicular Gastritis and Primary Gastric Lymphoma.

Chronic Disease↗
PubMed1998

Identification of functional domains in Efb, a fibrinogen binding protein of Staphylococcus aureus.

Staphylococcus aureus produces and secretes a protein, Efb, that binds to fibrinogen, seems to be required for virulence, and may benefit the microorganism by delaying wound healing. Interactions of Efb with fibrinogen are influenced by divalent metal cations, including Ca2+. Increasing concentrations of Ca2+ increased the binding of fibrinogen to immobilized Efb, whereas binding of Efb to immobilized fibrinogen was decreased with increasing Ca2+ concentration. Studies with synthetic peptides showed that peptides from the carboxyl terminal half of Efb bound to soluble fibrinogen and enhanced the binding of fibrinogen to Efb. A peptide corresponding to a repeated sequence in the amino terminal half of the protein also bound fibrinogen and inhibited binding of fibrinogen to Efb. These results may provide clues to the biological function of Efb and aid in the rational design of agents to block the Efb fibrinogen interaction.

Amino Acid Sequence↗
PubMed1998

Multiple binding sites in the interaction between an extracellular fibrinogen-binding protein from Staphylococcus aureus and fibrinogen.

Efb (previously Fib) is a fibrinogen-binding protein secreted by Staphylococcus aureus. It has previously been shown that it plays a role in a wound infection model in the rat and that antibodies against Efb reduce the number of recovered bacteria from the mammary glands in a mouse mastitis model. Efb binds to the alpha-chain of fibrinogen and does not participate in bacterial adherence to fibrinogen. The binding of Efb to fibrinogen is divalent, with one binding site within the two repeat regions in Efb at the N terminus and one binding site at the C terminus. The divalent binding nature leads to precipitation of Efb-fibrinogen complex when the proteins are added to each other at a 1:1 molar ratio. The interaction between Efb and fibrinogen is strongly enhanced by Ca2+ or Zn2+ but not by Mg2.

Animals↗
PubMed1996

Lack of the extracellular 19-kilodalton fibrinogen-binding protein from Staphylococcus aureus decreases virulence in experimental wound infection.

A mutant deficient for the 19-kDa extracellular fibrinogen-binding protein (Fib) from Staphylococcus aureus has been constructed. The gene was inactivated by allele replacement. A 2.0-kb fragment from transposon Tn4001 carrying the gene for gentamicin resistance was inserted into the gene encoding Fib (fib). The genotype was verified by PCR analysis, and the loss of Fib was demonstrated by Western blotting (immunoblotting). The mutation has not altered the ability of the strain to bind to fibrinogen or fibronectin compared with that of the isogenic parental strain, FDA486. The mutant, designated K4.3, was compared with strain FDA486 in a wound infection model in rats. Sixty-eight percent of the rats challenged with parental strain FDA486 developed severe clinical signs of wound infection, whereas only 29% of the animals challenged with isogenic mutant K4.3 showed severe symptoms (P < 0.01). The weight loss of animals infected with the wild type was also significantly different from that of animals infected with the mutant strain. The result demonstrates that the extracellular 19-kDa fibrinogen-binding protein from S. aureus contributes to the virulence in wound infection and delays the healing process.

Alleles↗
PubMed1996

Insertional inactivation of the gene for collagen-binding protein has a pleiotropic effect on the phenotype of Staphylococcus aureus.

This report describes phenotypical changes caused by the insertional inactivation of the gene for the collagen-binding protein in Staphylococcus aureus PH100. Insertional inactivation resulted in reductions in the amount of fibronectin-binding protein in PH100 and the ability of intact cells to aggregate in the presence of fibronectin. However, the capacity of PH100 to adhere to immobilized fibronectin remained the same.

Adhesins, Bacterial↗
PubMed1996

[Poor digestion of lactose. Its definition, prevalence in Mexico, and its implications in milk consumption].

We review the studies that have been carried out in Mexico related to prevalence of lactase deficiency. We also describe a study carried out in three regions of Mexico with different consumption of milk (Northern, Central & Southeastern), comprising 960 individuals of ages ranging from 1 to 99 years. They were evaluated in a double blind study in order to determine the prevalence of lactose maldigestion with habitual dosis of milk. Each subject received two treatments: a) 240 or 360 mL of intact milk according to age, and b) the same amount of milk but with the lactose hydrolyzed (> 90% hydrolyzed). The participants were classified as digesters or maldigesters of lactose using the hydrogen breath test. The prevalence of maldigesters was higher in the Central (30%) and Southeastern (22%) regions than in the Northern one (9%, p < 0.01). The prevalence increased with age from 4.5% (< 3 years), 13.6% (3 to 5.9), 20.8% (6 to 12.9), 21.8% (13 to 17.9) and 32.9% in adults. Lactose maldigestion affected consumption marginally.

Adolescent↗
PubMed1996

[Lactose intolerance. Its definition, its prevalence in Mexico, and its implications in milk consumption].

In this document we describe some aspects of lactose and milk intolerance, discuss the results of studies carried out previously in Mexico, and report an investigation whose objective was to quantify the impact of lactose intolerance on the habitual consumption of milk in an open population. The prevalence of lactose intolerance and its effect on the consumption of milk was studied in three regions of Mexico. The design of the study was prospective, randomized, double-blind and crossover. The presence of milk intolerance was investigated in 960 subjects with ages between 6 months and 99 years who, as a function of age, received 240 or 360 mL of intact milk and the same amount of hydrolyzed milk. We quantified the consumption of milk and the presence of symptoms after ingesting the tested milk. Seven percent manifested symptoms with the intact milk but only 2% with the hydrolyzed milk (p < 0.001). The presence of symptoms in the intolerant subjects was significantly associated with a lower consumption of milk in comparison with the tolerant individuals (p < 0.001). On the other hand, the consumption of milk appeared to be only marginally associated with the intolerance and its symptoms. We conclude that lactose intolerance does not appear to be a major factor in determining milk consumption in Mexican healthy populations.

Adolescent↗
PubMed1996

[Anatomopathological study of 86 gastric adenomas. Experience in 14 years].

AIM: To analyze the clinical presentation, pathological aspect and treatment of gastric adenomas. PATIENTS AND METHODS: Retrospective analysis of 75 patients aged 26 to 88 years in whom a gastric adenoma was diagnosed. RESULT: Seventy one patients had elevated endoscopical lesions and two had depressed or flat lesions. Ninety percent of lesions were located in the gastric antrum. Pathological study detected 6 focal carcinomas within the adenomas and 5 concomitant carcinomas located elsewhere in the stomach. Fifty four patients were subjected to endoscopical resection. Among patients with focal carcinomas, a gastrectomy was performed in four and endoscopical resection in two. CONCLUSIONS: Gastric adenomas must be considered in the differential diagnosis of gastric elevated lesions and may be confused in early gastric cancer. There is a histological resemblance between adenomas and gastric dysplasia described by several authors though only in our cases and in the Japanese literature the adenoma is referred to as mostly a polypoid sessile lesion.

Adenoma↗
PubMed1995

Effects of intravenous digoxin on pulmonary venous and transmitral flows in patients with chronic heart failure of different degrees.

Acute effects of digoxin on diastole were evaluated noninvasively by combining data simultaneously obtained by Doppler echocardiograms (echo-Doppler) of transmitral and pulmonary venous flow curves in 38 patients with dilated and failing hearts, who had been stable for at least 7 days before the study. According to the resting ejection fraction (EF), patients were subdivided into Group 1 (EF < 30%: n = 20, mean EF values 23 +/- 8%) and Group 2 (EF > or = 30%: n = 18, mean EF values 40 +/- 3%). Significant differences were observed at rest between the two groups in both transmitral (shorter deceleration time and isovolumic relaxation time and increased peak E and E/A ratio in Group 1 vs. Group 2) and transpulmonary (reduced systolic forward component and systolic fraction of the flow curves in Group 1 compared with Group 2 and control subjects) parameters. Digoxin (1 mg subdivided into two doses, each infused over a 15-min period with 2 h between the doses) significantly modified the diastolic profile in Group 1 patients in the absence of statistically relevant changes in EF: a significant decrease of transmitral peak E (from 76 +/- 17 to 60 +/- 15 cm/s, p < 0.05) and E/A ratio (from 2.5 +/- 1 to 1.6 +/- 0.6; p < 0.05) and a significant lengthening of deceleration time (from 115 +/- 20 to 160 +/- 18 ms; p < 0.05) were detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Splanchnic and systemic hemodynamics in early abstinence and after ethanol administration in non-cirrhotic alcoholic patients.

Thirteen asymptomatic chronic alcoholic patients were studied to investigate the early stages of portal hypertension in alcoholic liver disease and the effects of withdrawal and ethanol on hepatic function and hemodynamic variables. None of the patients presented clinical signs of decompensated liver disease, and their liver biopsies showed normal liver or moderate alterations only. In basal conditions and after an intravenous ethanol infusion (1 g/kg body weight), hepatic venous pressure gradient and hepatic blood flow using indocyanine green were measured through hepatic vein catheterization. Hepatic sinusoidal vascular resistance and indocyanine green intrinsic clearance were also calculated. Portal blood flow measurements were obtained by Doppler ultrasound. No correlation was observed between hepatic venous pressure gradient and histologic features, (steatosis, necrosis, fibrosis, inflammation and hepatocyte surface area). In basal conditions, portal hypertension was not found in any case. After ethanol, portal pressure increased significantly (p < 0.001); in four cases it rose to or above 5 mmHg. Portal blood flow, hepatic blood flow and hepatic vascular resistance also increased significantly. Intrinsic indocyanine green clearance decreased slightly but significantly. No significant correlations were found between portal pressure, hepatic resistance and the histologic parameters. It was concluded that alcoholic patients, without clinical or laboratory evidence of liver failure and with minimal or moderate histologic alterations, have normal portal pressures. After an intravenous ethanol load, however, four out of 13 patients (31%) reached levels of 5 mmHg or more, irrespective of their liver histology.

Adult↗
PubMed1994

Lactose maldigestion and milk intolerance: a study in rural and urban Mexico using physiological doses of milk.

Lactose digestion capacity after ingestion of physiological doses of milk and its effect on milk intolerance and consumption were studied in rural and urban populations from three regions of Mexico with different milk intakes. All subjects (n = 926) received two treatments: whole milk (240 mL for children and 360 mL for adults) and the same amount of 90% lactose-hydrolyzed milk; 72% of the subjects also received as a third treatment a water solution containing lactulose (8 g for children and 10 g for adults). Lactose maldigestion determined by a hydrogen breath test was detected in 2 to 43% of subjects (depending on age group) and was higher in subjects from central and southern Mexico than in subjects from northern Mexico (P < 0.01). Only the experience of major symptoms of intolerance affected milk consumption, and these symptoms were present in 0 to 11% of children > 4 y old and in 7 to 17% of the 13- to 60-y-old subjects. No significant differences were found in lactose maldigestion or milk intolerance between rural and urban populations, but milk consumption was higher in urban areas (P < 0.01). Milk consumption in our study was affected primarily by factors not related to the capacity to digest or tolerate the lactose in milk.

Adolescent↗
PubMed1994

[Primary gastric lymphoma. Analysis of 86 cases].

We report the retrospective analysis of 86 patients with primary gastric lymphoma diagnosed in a period of 12 years, that constitute 5.6% of malignant gastric lesions diagnosed in that lapse. Upper gastrointestinal endoscopy diagnosed a malignant lesion in 93% and lymphoma in 36% of cases. Endoscopic biopsies disclosed malignant lesions in 79 cases (93%) and were diagnostic of lymphoma in 70 (82%). All patients were operated, including the seven subjects in which the biopsy did not show malignant lesions; the surgical indication of the latter was based in clinical grounds. The macroscopic examination of the surgical piece showed ulcerated lesions in 45 (52%) and mixed lesions (ulcerated and protruded with and without multiple erosions) in 15 (18%) patients. Seventeen patients (33%) had an early lesion of the MALT type (mucosa associated lymphoid tissue) and 87% of lesions were of low or intermediate histological type.

Adolescent↗
PubMed1993

Effects of flecainide and propafenone on systolic performance in subjects with normal cardiac function.

Flecainide and propafenone are effective in suppressing both ventricular and supraventricular tachyarrhythmias, but their efficacy is often limited by dose-related side effects. This study was performed to evaluate noninvasively the effects of intravenous flecainide and propafenone on left ventricular systolic function indices in a selected population of 40 subjects (28 men and 12 women; mean age, 25 years) with normal cardiac structure and performance. Echocardiographic indexes of global systolic pump function (ejection fraction [EF] and percentage of fractional shortening [percent FS]) as well as monodimensional parameters of the intraventricular septum (IVS) and left ventricular posterior wall (PW) contractility (percent systolic thickening [percent th] and systolic excursion [ex]) were assessed in all subjects at baseline, immediately after, and in the early recovery (15 min) after randomized injection of either flecainide or propafenone. Heart rate and blood pressure did not significantly change after both drugs. A significant increase (p < 0.001) in left ventricular systolic internal diameter was observed after both flecainide and propafenone; simultaneously a significant decrease of percent FS (p < 0.001), EF (p < 0.001), PW percent thickening (th) (p < 0.001), and PWex (p < 0.001 after flecainide and p < 0.01 after propafenone) was recorded. These changes were comparable and promptly reversible. In analyzing individual data, a marked systolic dysfunction was observed in two patients after intravenous flecainide (percent FS from 37 percent to 17 percent and from 42 percent to 13 percent; EF from 55 percent to 40 percent and from 65 percent to 35 percent, respectively) and in one patient after intravenous propafenone (percent FS from 30 percent to 15 percent; EF from 58 percent to 35 percent). We conclude that both intravenous flecainide and propafenone exhibit mild negative inotropic effects leading to a moderate and reversible reduction of left ventricular systolic performance; however, in some cases, a dramatic impairment of systolic pump function may occur, suggesting careful use of both drugs as first-line agents also in normal subjects; finally, the true incidence of this deleterious effect is still unknown.

Adolescent↗