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Biomedical subjects

S Ferrer

Publications and source records attributed to S Ferrer.

At least 55 records · Page 3Linked to original sources
PubMed1995

Protection against bacteriocin 28b in Serratia marcescens is apparently not related to the expression of an immunity gene.

The gene encoding bacteriocin 28b from Serratia marcescens N28b (bss gene) has been cloned in Escherichia coli and its nucleotide sequence has been determined. The genetic determinants coding for other well-characterized bacteriocins from enterobacteria (colicins) are located in plasmids and they have always been shown to contain a gene responsible for immunity located downstream from the bacteriocin structural gene. In some cases there is another gene located downstream from the immunity gene, which is responsible for bacteriocin release. Analysis of bacteriocin 28b release and the sensitivity to this bacteriocin of E. coli strains harbouring recombinant plasmids containing the bss gene showed that bacteriocin 28b is not released from the cell in these strains and that their phenotypic insensitivity is not associated with any region close to the structural gene. The nucleotide sequence of the region downstream from the bss gene contains two putative open reading frames transcribed in the opposite direction to the bss gene. These open reading frames apparently encode proteins that seem not to be involved in bacteriocin immunity or release. Moreover, a S. marcescens N28b genomic library was screened and no immunity gene was found. Therefore, bacteriocin 28b differs greatly from the bacteriocins from other enterobacteria, and in the following senses it is unique: firstly, the gene encoding bacteriocin 28b seems to be located on the chromosome, and secondly, insensitivity to this bacteriocin in S. marcescens N28b is not associated with the expression of an immunity gene.

Amino Acid Sequence↗
PubMed1995

[Eosinophilic pustular folliculitis in acquired immunodeficiency syndrome. Report of 6 cases].

Eosinophilic pustulous foliculitis (EPF) is a rare dermatosis which has been reported in association with the human immunodeficiency virus infection. Six patients infected with HIV are reported with advanced disease in whom the diagnosis of EPF was made. All patients has a highly pruritic follicular papular rash. In all cases the pathology study revealed a mixed inflammatory infiltrate with predominance of eosinophils at the infundibulum of the pilous folliculi. Two patients had eosinophilia in peripheral blood. Therapy with antihistaminic agents and topical corticosteroids was ineffective in all cases. A favourable therapeutic response was achieved with phototherapy associated with the topic application of disodium cromoglycate 4%.

Adult↗
PubMed1994

Transformation of Aspergillus parasiticus using autonomously replicating plasmids from Aspergillus nidulans.

A genetic transformation system for the aflatoxin-producing fungus Aspergillus parasiticus using two autonomously replicating plasmids from A. nidulans (ARp1 and pDHG25) is reported. Transformation frequencies using the plasmid pDHG25 were from 5 x 10(2) to 2.5 x 10(4) transformants per 10(6) viable protoplasts and microgram DNA. The stability of the plasmids in the transformants was also studied. This transformation system offers a new opportunity to clone genes related to aflatoxin production using appropriate aflatoxin-defective mutants.

Aspergillus↗
PubMed1994

[Polyneuropathies and dysglobulinemias].

We review the concept fo Monoclonal Gammopathy emphasizing that the so called benign forms, with or without polyneuropathy can have an unpredictable evolution. Polyneuropathies associated to monoclonal gammopathy-IgM, IgG, IgA, Waldestrom's disease, Multiple myeloma, Osteosclerotic myeloma (POEMS), Amyloidosis and Cryoglobulinemias are reviewed. They generally are solely sensory, sensorimotor or rarely, solely motor. The importance of neuro-physiological studies and nerve biopsy is emphasized. For progressive forms, treatment with plasmapheresis, immunotherapy, corticoids or intravenous gammaglobulin is suggested.

Aged↗
PubMed1993

Nucleotide sequence of a Trichophyton mentagrophytes HindIII mitochondrial DNA fragment containing a tRNA gene cluster.

A 0.85-kb HindIII mitochondrial DNA fragment of the dermatophytic fungus Trichophyton mentagrophytes has been sequenced. The fragment contains eight complete genes which corresponds to a tRNA gene cluster. From 5' to 3', the sequenced genes code for tRNA(thr), tRNA(glu), tRNA(val), tRNA(met1), tRNA(met3), tRNA(leu), tRNA(ala), and tRNA(phe). This tRNA gene cluster is located downstream of the larger ribosomal RNA gene. The particularities of the sequenced genes and their comparison with other fungal tRNA mitochondrial genes are reported.

Base Sequence↗
PubMed1993

[Clinical correlations and evoked potentials in 29 cases of definitive multiple sclerosis].

Aiming to correlate the alterations in evoked potentials with the initial clinical manifestations of multiple sclerosis, 29 patients with the disease were studied and 19 were followed for a lapse ranging from 1 to 11 years. Visual evoked potentials were studied in all the patients and 51% were abnormal. Auditory evoked potentials were assessed in 26 patients and 26% were abnormal. Somatosensory evoked potentials were made in 21 patients and 61% were abnormal. We found no relationship between clinical status and abnormalities in evoked potentials. In the followed patients, those with the worst clinical deterioration, initially had cerebellar symptoms and pyramidal signs did not predict a bad evolution. There was no relationship between evolution time and aggravation of the disease. There was no general correlation between clinical evolution and alterations in evoked potentials however the presence of bilaterally abnormal auditory evoked potentials was a predictor of bad prognosis. It is concluded that evoked potentials are relevant diagnostic tools in multiple sclerosis, specially when they detect subclinical alterations.

Adult↗
PubMed1993

[Cerebral abscess caused by Toxoplasma gondii and AIDS. Report of a case with anatomo-pathological study].

We report a 47 year old woman that presented to the hospital with an intracranial hypertension syndrome, a right hemiparesis and a several months history of progressive malaise and behavioral disturbances. During the hospital stay, positive HIV antibodies were detected and CAT scan showed a profound left parietal rounded hypodense lesion. The patient died 21 days after admission and the postmortem pathological study showed a deep abscess in the left basal ganglia, with recognizable Toxoplasma gondii trophozoites.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Cloning and DNA sequence analysis of a bacteriocin gene of Serratia marcescens.

Serratia marcescens N28b synthesized and secreted a bacteriocin, with a molecular mass of 45 kDa, which was capable of inhibiting the growth of Escherichia coli. The expression of this bacteriocin was negligible unless induced with mitomycin C. The genes encoding the bacteriocin were cloned in plasmid pBR328. E. coli harbouring recombinant plasmid pBA189 or pBA289 expressed the Serratia marcescens N28b bacteriocin. The nucleotide sequence of the bss gene (Serratia marcescens N28b bacteriocin structural gene) was determined. The predicted amino acid sequence of the carboxy-terminal part of the bacteriocin 28b had a high degree of similarity to the pore-forming domains of colicins A, E1, B, N, Ia and Ib.

Amino Acid Sequence↗
PubMed1991

[Gammagraphy with sucralfate labelled with technetium in esophagitis].

In previous studies it has been reported that, after being labeled with technetium, sucralfate, an useful drug in peptic diseases, can be used to detect peptic lesions of the digestive tract. In this work we report our experience with this technique in the diagnosis of esophagitis. 25 studies (11 controls and 14 patients) were undertaken. Sucralfate scintigraphy was normal in the 11 control studies, and abnormal in 10 out of 14 patients. Scintigraphy was abnormal in peptic as well as caustic lesions.

Adult↗
PubMed1990

[Physiopathology of migraine].

The basic theories on the origin of migraine are reviewed. A vascular paroxysm was the initial hypothesis, followed by the "spreading depression" phenomenon based of regional flow studies of Danish authors. A third hypothesis relates the origin of migraine to liberation of substance "p" and others (K, neurotransmitters and polypeptides) from trigeminal nerve endings. Finally, a behavioral disturbance originating an adrenergic response and a loss of central nervous system defense mechanisms, has been also postulated.

Cerebrovascular Circulation↗
PubMed1990

[Idiopathic tumoral calcinosis. A clinical case].

A 25-year-old Chilean woman of Jewish ancestry developed subcutaneous nodules at the thighs, axillae, elbows and coccygeal areas. X rays disclosed heavily calcified lesions at these levels. The patient's father had Whipple's disease, her mother and one brother had early hip osteoarthrosis and one son had idiopathic pancreatitis. Laboratory studies ruled out hyper or hypoparathyroidism. Electromyogram showed evidence of mild myopathy and inflammatory elements were present on muscle biopsy. However, the diagnosis of polymyositis associated to calcinosis was ruled out. Skin biopsy disclosed calcifications and fat necrosis. After 20 years of follow up, an increase in calcification specially at the pelvis and periarticular regions has been observed. Etiology, differential diagnosis and treatment are discussed.

Arthrography↗