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Biomedical subjects

R Serrano

Publications and source records attributed to R Serrano.

At least 181 records · Page 10Linked to original sources
PubMedDate not supplied

Physiology of mutants with reduced expression of plasma membrane H+-ATPase.

Two mutations containing insertions and deletions in the promoter in the plasma membrane H+-ATPase gene (PMA1) of Saccharomyces cerevisiae have been introduced into the genome by homologous recombination, replacing the wild-type gene. The resulting strains have 15 and 23% of the wild-type ATPase content. Decreased levels of ATPase correlate with decreased rates of proton efflux and decreased uptake rates of amino acids, methylamine, hygromycin B and tetraphenylphosphonium. This supports a central role of the enzyme in yeast bioenergetics. However, the final accumulation gradient of tetraphenylphosphonium is not affected by the mutations and that of methylamine and 2-aminoisobutyric acid is only decreased in the most extreme mutant. Apparently, kinetic constraints seem to prevent the equilibration of yeast active transports with the electrochemical proton gradient. As expected from their transport defects, the ATPase-deficient mutants are more resistant to hygromycin B and more sensitive to acidification than wild-type yeast. Mutant cells are very elongated, suggesting a structural role of the ATPase in the yeast surface.

Biological Transport, Active↗
PubMedDate not supplied

Effects of prepro-vasoactive intestinal peptide-derived peptides on the murine immune response.

We have studied the effects of prepro-vasoactive intestinal polypeptide-derived peptides on lectin-induced lymphocyte proliferation and natural killer cell (NK) activity in cells from murine spleen, mesenteric lymph nodes, Peyer's patches, thymus and peripheral blood mononuclear lymphocytes (PBL). These peptides (vasoactive intestinal peptide (VIP), peptide histidine methionine (PHM-27) and peptide histidine valine (PHV-42)) showed differential effects in their immune response in a dose- and tissue-dependent manner. All peptides significantly decreased DNA synthesis in spleen (range: 45-30%), lymph nodes (range: 30-0%), Peyer's patches (range: 30-4%) and PBL (range: 30-16%). In these tissues there was no significant difference in their potency. In the thymus, however, PHM-27 (range: 27-15%) was significantly more potent (p less than 0.001) in inhibiting DNA synthesis than either VIP (range: 6-0%) or PHV-42 (range: 20-8%). The modulatory effects on NK activity by these peptides also showed an inhibitory effect. The order of potency was: VIP (range: 40-27%), PHV-42 (range: 22-11%) and PHM-27 (range: 20-8%). The presence of VIP inhibitor [( D-p-chloro-Phe6,Leu17]-VIP) at 10(-8) M in both functional assays caused a significant antagonism of the effects of VIP but not PHM-27 or PHV-42. Our results suggest the existence on lymphocytes of different receptors for prepro-VIP-derived peptides, and that they may be considered as important immunoregulatory molecules. Their mechanism of interaction, however, is not clearly understood.

Animals↗
PubMedDate not supplied

Effects of acute benzene exposure on brain enkephalin immunostaining and degradation.

Benzene is a widely used industrial neurotoxin. Its action in the brain is not completely clear. Acute exposure to benzene in vivo reduces aminopeptidase activity in the hypothalamus and in the brain stem, and in vitro treatment with this toxicant generates a dose-related inhibition of this enzyme, notably in the brain stem. Enkephalin immunostaining shows a significant increase in substantia nigra, central gray (dorsal, lateral and pontine), and tegmental nuclei in acute in vivo benzene-treated rats with respect to controls. In summary, this work shows an effect of benzene on the enkephalinergic system, which could be related to the naloxone-reversible analgesia induced by the aromatic hydrocarbon.

Aminopeptidases↗
PubMedDate not supplied

Yeast plasma membrane ATPase is essential for growth and has homology with (Na+ + K+), K+- and Ca2+-ATPases.

The plasma membrane ATPase of plants and fungi is a hydrogen ion pump. The proton gradient generated by the enzyme drives the active transport of nutrients by H+-symport. In addition, the external acidification in plants and the internal alkalinization in fungi, both resulting from activation of the H+ pump, have been proposed to mediate growth responses. This ATPase has a relative molecular mass (Mr) similar to those of the Na+-, K+- and Ca2+-ATPases of animal cells and, like these proteins, forms an aspartylphosphate intermediate. We have cloned, mapped and sequenced the gene encoding the yeast plasma membrane ATPase (PMA1) and report here that it maps to chromosome VII adjacent to LEU1. The strong homology between the amino-acid sequence encoded by PMA1 and those of (Na+ + K+), Na+-, K+- and Ca2+- ATPases is consistent with the notion that the family of cation pumps which form a phosphorylated intermediate evolved from a common ancestral ATPase. The function of the PMA1 gene is essential because a null mutation is lethal in haploid cells.

Adenosine Triphosphatases↗
PubMedDate not supplied

MHC class I expression on human tumour cells and their susceptibility to NK lysis.

Although natural killer (NK) activity is not restricted by the major histocompatibility complex (MHC), it has been suggested that the level of expression of MHC antigens by target cells may influence their lysis by NK cells. We have studied the NK susceptibility of 20 cell lines obtained from primitive and metastatic human tumours and the K562 cell line treated with gamma-interferon, phorbol ester TPA and tumour factor NK-RIF. When the levels of MHC class I antigen expression on the human tumour cell lines and their NK susceptibility were compared, no relationship between these two parameters was observed. Furthermore the treatment of K562 with either gamma-interferon, TPA or NK-RIF decreased its NK susceptibility independently of MHC class I expression. These results indicate that the MHC class I antigen is not the only factor directly involved in NK susceptibility and suggest that other membrane structures modulated by gamma-interferon, TPA or NK-RIF may also influence NK susceptibility.

Cytotoxicity, Immunologic↗
PubMedDate not supplied

Fine needle aspiration cytology of metastatic hepatic adrenocortical carcinoma mimicking hepatocellular carcinoma: a case report.

BACKGROUND: Adrenocortical carcinoma (AC) is a rare neoplasm, usually considered one of the most morbid and lethal human tumors. It occurs primarily in children and young adults and often presents with advanced and/or metastatic disease. CASE: A 9-year-old boy with a previous diagnosis of adrenocortical carcinoma underwent computed tomography (CT)-guided fine needle aspiration (FNA) for preoperative investigation of a hepatic mass. All smears revealed abundant groups of cells surrounding an interconnective, thin-walled, central vascular core. These cells showed finely vacuolated, large cytoplasm with eccentrically placed nuclei. Occasionally, cells underwent a sudden, marked increase in size, with prominent atypia. Multinucleated, atypical giant cells and high mitotic rate were also evident. The cytologic findings resembled the previous histologic adrenocortical carcinoma features. CONCLUSION: The cytologic features of metastatic hepatic adrenocortical carcinoma may mimic those of hepatocellular carcinoma. However, the presence of atypical multinucleated and pleomorphic cells with microvacuolated cytoplasm and eccentric nuclei as well as the absence of naked nuclei and endothelial linings yield the diagnosis of adrenocortical carcinoma. Nevertheless, other space-occupying liver lesions in children must also be considered. This case demonstrates the usefulness of CT-localized FNA biopsy in hepatic masses in children, and discusses the possible cytologic differential diagnosis.

Adrenal Cortex Neoplasms↗
PubMedDate not supplied

Liesegang rings in a dermoid cyst of the floor of the mouth. Report of a case with cytologic findings.

BACKGROUND: Eosinophilic, ring-shaped structures, referred to as Liesegang rings (LRs), have been identified in aspirates from many organs, usually in relation to cystic or inflammatory lesions, but never before in relation to a dermoid cyst. CASE: LRs were intermingled with squamous cells in aspirates from a cyst of the floor of the mouth. The patient, a 23-year-old man, presented with a sublingual mass that had recently grown. Histopathologic study showed a ruptured dermoid cyst with mural foci of granulomatous foreign body reaction mixed with numerous ringlike structures, LRs. CONCLUSION: To the best of our knowledge, this is the first reported case of LRs in a dermoid cyst. Pathologists should be aware of this association when diagnosing cystic lesions.

Adult↗
PubMedDate not supplied

Lymphoepithelial cyst with crystalloid formation. Cytologic features of two cases.

BACKGROUND: The presence of amylase crystalloids (AC) in cystic lesions of the parotid gland is a rare occurrence and has been diagnosed to date as sialadenitis. We report the first two cases of parotid lymphoepithelial cyst (LC) containing this type of crystalloid. CASES: Case 1, a 56-year-old male, presented with a 3-cm parotid cyst. Fine needle aspiration (FNA) was performed on the mass. Smears showed numerous crystalloids identical to those described as crystallized amylase. Case 2, a 36-year-old female, had a 2-cm parotid mass. FNA smears exhibited the same features as did case 1. The two patients were treated with superficial parotidectomy, and an LC containing AC was diagnosed in both cases. CONCLUSION: When the above findings are present on FNA of parotid gland, the diagnosis of LC must be considered.

Adult↗
PubMedDate not supplied

Effect of subacute toluene administration on the enkephalinergic neuromodulatory system in rats and protective action of ganglioside treatments.

Gangliosides perform protective functions in the central nervous system. This paper describes a study of the effect of ganglioside administration on toluene neurotoxicity. Rat brain met-enkephalin immunostaining in the central amygdaloid nuclei showed changes in rats treated simultaneously with gangliosides and toluene with respect to rats treated with toluene alone. It is suggested that gangliosides prevent toluene neurotoxicity at this level, leading to hypothetical neurobehavioral changes.

Animals↗
PubMedDate not supplied

Civil rights in a changing health care system.

Title VI of the 1964 Civil Rights Act prohibits discriminatory conduct by recipients of federal financial assistance. The law has been used in the past to challenge discrimination in health care. The evolution of the health care system from fee-for-service to managed care holds much promise for minority persons, who historically have faced serious, extensively documented barriers to health care access. However, managed care providers, like their fee-for-service counterparts, may perpetuate past discriminatory practices in new ways. Understanding new forms of discrimination is important at this stage of the development of managed care, when program design and policy action can most effectively prevent the occurrence of such practices.

Civil Rights↗
PubMedDate not supplied

[Bacteremia in a community hospital. Review of 78 cases].

We analyze retrospectively all bacteremic episodes seen between January and December, 1987 in our institution. From a total number of blood cultures performed of 897, 145 were positive (16%), and 67 of them considered as contamination (7.5%). There were 78 episodes of bacteremia in 74 patients, 38 males and 36 females. Forty-eight episodes were community-acquired and 30 were nosocomial bacteremia episodes. Aerobic bacteria were isolated in 64 cases, anaerobic bacteria in 9 cases and polymicrobial bacteremia in 5 cases. The most commonly isolated microorganism was S. epidermidis in nosocomial cases and E. coli in community-acquired cases. Predisposing conditions registered were diabetes mellitus in 16 cases (20%), cirrhosis of the liver in 3 (4%), corticosteroid therapy in 7 (9%) and surgical procedures in 19 (24%). Shock was seen in 16 cases (20%), DIC in 8 cases (10%) and ARDS in 5 (6.5%). Appropriate antibiotic treatment was used in 60 episodes (77%). Seventeen patients (22%) died. Prognostic factors identified were: nosocomial bacteremia (p less than 0.05), corticosteroid prior therapy (p less than 0.05), underlying disease UF or RF (p less than 0.0001) and the presence of shock (p less than 0.0001). Mean hospital stay was 20.1 days in bacteremic patients vs. 7.6 days in non bacteremic patients (p less than 0.00001).

Adult↗