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Biomedical subjects

H Fernández

Publications and source records attributed to H Fernández.

At least 19 recordsLinked to original sources
PubMed2002

LC determination of loratadine and related impurities.

Loratadine, an antihistamine, could include in its raw material seven impurities that ought to be separated identified and quantified for drug development and quality control. A HPLC method employing a SymmetryShield RP8 column has been developed and validated for loratadine and related compounds measurement, the last ones under the 0.1% level. The mobile phase consisted of methanol-buffer A (65:35, v/v), being buffer A: H(3)PO(4) 10 mM (H(2)O) brought up to pH 7.00 with triethylamine. UV detection was performed at 244 nm. Validation parameters for linearity, accuracy and precision are in agreement with ICH guidelines for all the analytes and that permits to consider the method reliable and suitable for application to long-term stability and purity studies.

Chromatography, High Pressure Liquid↗
PubMed2001

Antibodies anti-Chlamydia pneumoniae and anti-Mycoplasma pneumoniae in patients with negative serology for hantavirus. Retrospective study.

The seroprevalence of Chlamydia pneumoniae and Mycoplasma pneumoniae in hantavirus seronegative patients, who had symptoms and signs compatible with pneumonia was established. For this purpose we used the indirect fluorescent antibody test. Titers > or = 1:16 for C. pneumoniae and M. pneumoniae were found in 8.6% and 17.1% of the serum, respectively, showing evidence of recent or current infection.

Adolescent↗
PubMed2000

Heart transplantation: influence of the surgical technique on sinus function.

This study analyzes the influence of the surgical technique on the development of sinus dysfunction. Cycle length, corrected sinus node recovery time, and sinoatrial conduction time were determined in 4 groups of dogs under the following conditions: group 1, controls; group 2, subjected to heterotopic heart transplantation with conservation of atrial anatomy; group 3, subjected to orthotopic heart transplantation by using a standard technique; and group 4, treated as in group 3, but with an ischemic time of 24 hours. The cycle length was prolonged in all the treated groups when compared with the controls (P < .01), an effect attributed to the disconnection of the autonomic nervous system during the transplantation procedure. The corrected sinus node recovery time and sinoatrial conduction time were significantly longer in all the animals in groups 3 and 4 when compared with those of groups 1 and 2 (P < .01); however, there were no significant differences between groups 3 and 4 or between groups 1 and 2. These results suggest that the atrial anatomy play a more relevant role than the ischemic time in the origin of sinus dysfunction occurring after orthotopic heart transplantation.

Animals↗
PubMed2000

Expression of invasiveness of Campylobacter jejuni ssp. jejuni after serial intraperitoneal passages in mice.

We investigated the possibility of inducing the expression of invasiveness in 10 non-invading, laboratory-adapted Campylobacter jejuni ssp. jejuni strains, after serial intraperitoneal (i.p.) passage in mice. All the strains expressed invasive capacity after the first passage, with an increase in invasion rates and the number of internalized bacteria after each passage. These results suggest that i.p. passage enhances the expression of invasiveness in C. jejuni ssp. jejuni strains.

Animals↗
PubMed1999

[Tuberculosis in the V Sanitary Zone of Buenos Aires Province. Analysis of its trends between 1984 and 1996].

Tuberculosis (TB) continues to be a serious health problem in most of the districts in the 5th Sanitary Region of Buenos Aires Province (RSV) which is located in North Buenos Aires City suburbs. The aim of this study was to analyse and compare the evolution of the TB epidemiological situation in ten districts, in a thirteen year period (1984-96) and to analyse possible reasons for differences. The average annual variation (VAP) of morbidity rate was calculated in order to estimate the trends of TB in these communities along time. Reporting to the National and Provincial TB Control Programmes of TB cases is mandatory for physicians and these data were used as a source of information for the number of cases and rates. A statistical analysis was performed. Our results showed that the VAP value for the whole RSV was lower than -5.0%. On this basis several districts were identified as having a TB critical situation. The proportion of smear positive cases among TB patients reported decreased during this period, suggesting that smear microscopy was being poorly used as a diagnostic tool for TB. Furthermore, the cure rates of the patients attained--in average--only 60.0% and several warning indicators (IA)--like TB meningitis cases and mortality due to TB in people younger than thirty years old, as well as TB--HIV/AIDS association--have been observed to grow in several districts. Previous world global experience and those obtained in other provinces in our own country, suggest that the unique possible strategy for modifying this situation, is to set up the directly observed treatment (DOTS), according to World Health Organization/International Union Against Tuberculosis and Lung Diseases (WHO IVATLD) recommendations, in order to achieve the control of TB.

Adolescent↗
PubMed1998

Cape Town solution in prolonged myocardial preservation: structural and ultrastructural study.

This study deals with myocardial preservation after 24 hours of continuous, hypothermic and oxygenated perfusion with Cape Town (CT) solution, focusing on the morphological changes produced by preservation and reperfusion, and their possible relationship to the composition of the solution and the immediate hemodynamic findings after orthotopic heart transplantation in dogs. After preservation, aside from mild or moderate mitochondrial changes, the most relevant lesions included edema and vasoconstriction. Reperfusion was followed by the development of areas of necrosis forming contraction bands and an increment in the mitochondrial damage; the intercalated disks conserved their normal structure; edema became more prominent and was invariably accompanied by hemorrhage; vasoconstriction was very pronounced and was accompanied on occasion by evidence of capillary rupture; and inflammatory cells were observed in the interstitium. These results indicate that colloid must be added to Cape Town solution and that reperfusion probably requires selective approaches to deal with vasoconstriction and inflammation.

Animals↗
PubMed1998

[Primary ureteral amyloidosis].

OBJECTIVE: Two additional cases of primary ureteral amyloidosis are described. The current literature and clinical classification of the disease are reviewed. METHODS: Over a period of 18 months, we observed two cases of organic ureteral stenosis whose etiology was difficult to determine. The first case warranted a nephroureterectomy due to the condition of the compromised urinary tract. Analysis of the surgical specimen showed histological evidence of ureteral amyloidosis. In the second case, the previous experience allowed a preoperative diagnosis to be made, an exceptional situation that permitted conservative surgery. Characterization of the amyloid proteins was done in both cases with immunochemical study by Western Blot. RESULTS: Two patients with primary ureteral amyloidosis were surgically treated. The first case underwent complete excision of the urinary tract. The second case, who had a single kidney, was treated by conservative surgery. In both cases we identified a fragment of the lambda light chain of immunoglobulin by Western Blot characterization as previously reported in localized amyloidosis. CONCLUSIONS: Although ureteral amyloidosis is an infrequent disease, it should be seriously considered in the differential diagnosis of organic ureteral stenosis in order to avoid unnecessary excision. To our knowledge, these are the first cases of ureteral amyloidosis with immunochemical characterization of the amyloid protein.

Aged↗
PubMed1998

[The relationship of Campylobacter jejuni subsp. jejuni enterotoxigenicity and the increase of cAMP and electrolyte changes in the rat intestine].

BACKGROUND: Small intestine alterations produced by the enterotoxigenic capacity of Campylobacter jejuni subsp. jejuni are similar to the hydric, electrolytic and pathological changes caused by choleraic and thermolabile Escherichia coli toxins. AIM: To study the enterotoxigenic capacity of 4 strains of Campylobacter jejuni subsp. jejuni using the intestinal loop model. MATERIAL AND METHODS: Rat intestinal loops were inoculated with culture filtrates of the four strains. Enterotoxigenicity was assessed by fluid accumulation, the increase in Na+ and Cl- in the loop fluid, and cAMP increase in loop tissues. An enterotoxigenic Escherichia coil strain and sterile Brucella both were used as positive and negative controls, respectively. RESULTS: The filtrates of two strains produced fluid accumulation in the loops, significantly increased Na+ and Cl- secretion to the intestinal lumen and increased tissue cAMP levels. CONCLUSIONS: Some strains of Campylobacter jejuni subsp. jejuni are able to show enterotoxigenicity in vivo, increasing cAMP levels in the intestinal cells and altering electrolyte exchange mechanisms.

Animals↗
PubMed1997

Use of interferon-alpha in laryngeal papillomatosis: eight years of the Cuban national programme.

Laryngeal papillomatosis is one of the first diseases where interferon (IFN) was found to be effective. In 1983, a programme for the treatment of all such cases started in Cuba. Up to December 1991, 125 patients (92 children, 33 adults) have been treated: 102 with leucocyte IFN-alpha, 12 with recombinant IFN-alpha-2b, and 11 have received both preparations. Case management consisted of surgical removal of the lesions followed by an IFN schedule starting with 10(5) IU/kg of weight in children or 6 x 10(6) IU in adults, i.m. daily. The dose was progressively reduced, as long as no relapses occurred. At the end of the one-year schedule the doses were reduced to 5 x 10(4) IU/kg in children or 3 x 10(6) IU in adults, weekly. If there was a relapse, it was removed surgically and the patient returned to a higher dose level. Most cases (89; 71 per cent) have not relapsed after the treatment; 60 of them have been followed for more than three years. In those with relapses, the frequency of recurrence decreased in all but four patients. The treatment seemed to be more effective if initiated less than three months after the disease onset. The tracheostomy could be removed in five out of seven patients who needed it before the IFN treatment and was necessary in only three new cases during IFN treatment. In two of these, decannulation was possible later on. In a total of 14 patients relapses persisted after several cycles of IFN treatment. They were considered resistant to such treatment. No severe side effects were reported. The most frequent ones were fever, drowsiness, increased bronchial secretion, chills and headache. The establishment of this programme has maintained the disease under control in Cuba.

Adolescent↗
PubMed1997

Occurrence of thermotolerant Campylobacter species in domestic and wild monkeys from Peru.

The isolation rate of thermotolerant campylobacters in pet monkeys and wild monkeys was established. Campylobacter spp. were isolated in 31.9% of the first (pet) group, being less frequent (20.9%) in the second (wild) (P > 0.05). In both groups, only biovars I and II of C. jejuni ssp. jejuni and both biovars of C. coli were isolated (Lior's scheme). Campylobacter lari was not isolated. The results show that domestic and wild monkeys can harbour Campylobacter in their intestinal tract and would be considered as reservoirs of these bacteria.

Animals↗
PubMed1997

Structural and ultrastructural study of the myocardium after 24-hour preservation in University of Wisconsin solution.

This study deals with myocardial preservation after 24 hours of continuous perfusion with University of Wisconsin (UW) solution, focusing on the morphological changes produced by preservation and reperfusion, and their possible relationship to the composition of the solution and the immediate hemodynamic findings after orthotopic heart transplantation in dogs. Following preservation, the histological images of the myocardium were normal in almost every case. After revascularization, although 50% of the hearts recovered preoperative functional levels, there were relevant histological changes in all of them. These changes consisted of interstitial edema, damage to at least 50% of the mitochondria, presence of contraction bands, loss of intercellular junction structure and vasoconstriction. According to these results, the association of continuous perfusion and UW solution appears to be effective during the ischemic period of prolonged myocardial preservation, but not during reperfusion. Perhaps the proportion of viable hearts could be increased by preventing vasoconstriction.

Animals↗
PubMed1996

Isolation of thermotolerant species of Campylobacter from commercial chicken livers.

The qualitative and quantitative contamination levels of Campylobacter spp. in frozen commercial chicken livers were assessed. From the 126 samples studied, 117 (92.9%) were positive for Campylobacter spp. C. coli was isolated more frequently (78.6%) than C. jejuni (21.4%). The MPN method showed that Campylobacter contamination levels ranged from 10 to > 230 bacteria/100 ml of liquid exuded by livers.

Animals↗
PubMed1996

[Intervention of Campylobacter jejuni subsp. jejuni flagella in the adhesion to cellular cultures: bacteriological and immunological evidence].

The participation of the flagella of a virulent strain (O52) of Campylobacter jejuni subsp. jejuni in the adhesion to HEp-2 cells and their inhibition by means of homologous polyclonal antibodies, monoclonal anti-flagella antibodies and colostral natural antibodies (IgA) was studied. An aflagellated strain (T1) was used as negative control. Adhesion was observed in higher rates with O52 strain (72%) than with T1 strain (27.5%). Polyclonal, monoclonal and colostral antibodies inhibited O52 strain adhesion in more than 70% (p < 0.001). T1 strain adhesion was inhibited only by polyclonal and colostral natural antibodies. Our results suggest that the flagella of C. jejuni subsp. jejuni could participate effectively in the adhesion process. However, the inhibition of T1 strain by polyclonal and colostral antibodies suggests the existence of other binds of adhesins in the bacterial surface.

Bacterial Adhesion↗
PubMed1996

[Participation of Campylobacter jejuni flagellar epitopes in cellular adhesion].

Using a flagellated (052) and an aflagellated (T-1) strains we studied the participation of flagellar epitopes of C. jejuni in the adhesion to HEp-2 cells in vitro. Strain 052 was significantly more adherent than strain T-1. When adhesion assays were carried out with antiflagella monoclonal antibodies, strain 052 showed inhibition of their adhesive capacity that varied between 64.3 and 92.9%. With an ELISA test it was demonstrated that those monoclonal antibodies were specific and directed exclusively against flagellar epitopes of strain 052 being unreactive with strain T-1. Our results show that flagellar epitopes could participate in the adhesion process suggesting that flagella could be involved in the installation of the infectious process.

Antibodies, Monoclonal↗
PubMed1995

Lesions of the medial prefrontal cortex and sexual behavior in the male rat.

Lesions of the cerebral cortex near the midline in the frontal region appearing to destroy most of the cingulate cortex and adjacent prefrontal areas had profound effects on male rat sexual behavior. At the first postoperative tests, one week after the lesion, the mount and intromission latencies were extremely long (> 60 min). They continued elevated at every fortnightly test until postlesion week 13, when they were no longer different from controls. However, the proportion of animals that intromitted or ejaculated was reduced at this time. The lesion had a slight effect on the number of intromissions and on the intromission ratio, but did not reliably modify other parameters of sexual behavior in those males that copulated after operation. These data suggest that the medial prefrontal cortex is important for the initiation of sexual behaviour but less so for its execution. It is proposed that the elaboration and/or interpretation of environmental stimuli are rendered deficient by the lesion. Consequently, sexual behavior is activated only with difficulty. This coincides with the arousal hypothesis proposed by Beach [8]. There appears to exist a spontaneous recovery of the mechanisms responsible for the activation of sex behavior because the lesioned group was not different from the sham or intact groups 13 weeks postlesion. Remaining cortical tissue or other brain structures may compensate for the initial deficiencies. However, the lesion's effect on intromission behavior did not diminish with time. This could suggest that possible motor deficiencies produced by the lesion are irreversible.

Animals↗
PubMed1995

[Isolation of thermotolerant species of Campylobacter from 2 populations of chickens bred in confinement and at liberty].

The isolation rates of thermotolerant Campylobacter species in free-ranging domestic chickens and confined chickens from Iquitos city, Peru, were determined. Campylobacter spp. were isolated in 54.0% of the former group of chickens, being less frequent (35.0%) in the latter (p < 0.05). Of the classical thermotolerant species, C. jejuni and C. coli were the most frequent. However, the presence C. lari suggests that the chickens might be an important reservoir of this bacterium.

Animals↗