Biomedical subjects

R Paniagua

Publications and source records attributed to R Paniagua.

At least 19 recordsLinked to original sources

PubMed2006

The p38 transduction pathway in prostatic neoplasia.

It has been proposed that, among other cellular responses, TNF-alpha induces not only cell death, but also cell proliferation by activation of p38. It has also been reported that IL-1-alpha favours cell proliferation by p38 activation. The aim of the present study was to evaluate upstream (alpha-PAK, MEK-6) and downstream (Elk-1 and ATF-2) components of the p38 transduction pathway in normal prostate, benign prostatic hyperplasia (BPH), and prostate carcinoma (PC). Immunohistochemical and western blot analyses were performed in 20 samples of normal prostate, 47 samples of BPH, and 27 samples of PC. In all normal prostates, immunoreactivity for p-Elk-1 and p-ATF-2 was observed in epithelial cell nuclei, but no expression of alpha-PAK or MEK-6. In BPH, there was expression of alpha-PAK (cytoplasm) and MEK-6 (cytoplasm), while the proportions of lesions that were immunoreactive for p-Elk-1 (nucleus and cytoplasm) and p-ATF-2 (nucleus) decreased. In PC, the percentages of cells that were immunoreactive for alpha-PAK (cytoplasm) or MEK-6 (cytoplasm) rose slightly in comparison with BPH, while the percentages of cells that were immunoreactive for p-Elk-1 (nucleus and cytoplasm) or p-ATF-2 (nucleus and cytoplasm) were much higher than in BPH. It is concluded that overexpression of alpha-PAK, MEK-6, p38, p-Elk-1, and p-ATF-2 in BPH, and more intensely in PC, enhances cell proliferation. In BPH, such proliferation is triggered by IL-1 and in part counteracted by the TNF-alpha/AP-1 pathway, which promotes apoptosis. In PC, proliferation is triggered by IL-1 and TNF-alpha (the TNF-alpha/AP-1 pathway is diverted towards p38 activation). Since in a study of the same patients immunoexpression of IL-1alpha and IL-1RI was previously observed to be increased in PC, inhibition of p38 is a possible target for PC treatment, as this inhibition would both decrease IL-1-induced cell proliferation and increase TNF-alpha-induced cell death.

Activating Transcription Factor 2↗

PubMed2006

P38 MAPK protects against TNF-alpha-provoked apoptosis in LNCaP prostatic cancer cells.

PURPOSE: One of the most relevant aspects in cell death regulation is the signalling of apoptosis by the serine/threonine kinases MAPKs. The aim of this study was to investigate the effects of TNF-alpha stimulation on MAPK activation, and the pro- or anti-apoptotic role of these kinases in LNCaP and PC3 cells. MATERIAL AND METHODS: Treatments were carried out using several TNF-alpha concentrations, as well as specific pharmacological inhibitors of MAPKs. Apoptosis rates were evaluated by DAPI staining and flow cytometry. MAPK phosphorylation/activation was measured by Western blot. RESULTS: TNF-alpha induced apoptosis in a dose-dependent manner in LNCaP but not in PC3 cells. The MAPK inhibitors revealed that the apoptotic rate in LNCaP cells increased significantly following p38 inhibition. The kinase inhibitors failed to cause changes in apoptosis in PC3 cells. CONCLUSIONS: The potentiation of apoptosis by p38 inhibition points to this kinase as a possible target for the treatment of androgen-dependent prostatic cancer.

Anthracenes↗

PubMed2006

Cell cycle control related proteins (p53, p21, and Rb) and transforming growth factor beta (TGFbeta) in benign and carcinomatous (in situ and infiltrating) human breast: implications in malignant transformations.

A comparative study of the products of the cell cycle control genes p53 (mutated form), p21, Rb (nonphosphorylated and phosphorylated form) and TGFbeta was performed by immunohistochemistry and Western blot, in benign breast disorders and breast cancer (in situ and infiltrating tumors). For the five proteins studied, the relative numbers of positively stained cells were higher in in situ carcinoma than in benign breast diseases. In infiltrating breast tumors, the relative numbers of positively stained cells were even higher than in in situ tumors except for the percentage of pRb immunostained cells, which decreased slightly in infiltrative tumors. For the other four proteins, the percentages of positively stained cases were similar to those found in in situ tumors. In the three groups of patients, TGFbeta immunoreaction appeared in the cytoplasm while immunoreactions to p53, p21, Rb, and pRb were found always in the nucleus except for p21 in in situ tumors, which showed cytoplasmic immunoreaction. Present results suggest that accumulation of mutated p53, cytoplasmic p21, and pRb in breast gland epithelium might be a crucial point in the development of in situ adenocarcinoma. In the infiltrating tumors, the expression of p21 in the nuclei and the decrease in pRb expression suggest an insufficient attempt to hinder cell proliferation.

Adult↗

PubMed2005

Influence of thyroid hormone receptors on breast cancer cell proliferation.

BACKGROUND: The involvement of thyroid hormones in the development and differentiation of normal breast tissue has been established. However, the association between breast cancer and these hormones is controversial. Therefore, the objective of the present study was to determine the protein expression pattern of thyroid hormone receptors in different human breast pathologies and to evaluate their possible relationship with cellular proliferation. PATIENTS AND METHODS: The presence of thyroid hormone receptors was evaluated by immunohistochemistry and western blot analysis in 84 breast samples that included 12 cases of benign proliferative diseases, 20 carcinomas in situ and 52 infiltrative carcinomas. RESULTS: TR-alpha was detected in the nuclei of epithelial cells from normal breast ducts and acini, while in any pathological type this receptor was located in the cytoplasm. However, TR-beta presented a nuclear location in benign proliferative diseases and carcinomas in situ and a cytoplasmatic location in normal breast and infiltrative carcinomas. The highest proliferation index was observed in carcinomas in situ, although in infiltrative carcinomas an inverse correlation between this index and the TR-alpha expression was encountered. CONCLUSIONS: The results of this study reveal substantial changes in the expression profile of thyroid hormone receptors suggesting a possible deregulation that could trigger breast cancer development.

Blotting, Western↗

PubMed2005

IL-6, its receptors and its relationship with bcl-2 and bax proteins in infiltrating and in situ human breast carcinoma.

AIMS: To characterize the expression pattern of IL-6 and its receptors (IL-6R(alpha) and gp130), to relate this pattern to bcl-2 and bax expression and to elucidate the effects on the proliferation/apoptosis equilibrium in benign conditions and in situ and infiltrating breast cancer. METHODS AND RESULTS: The immunoexpression of IL-6 and its receptors (IL-6R(alpha) and gp130), and their relationship with bcl-2 and bax proteins, were studied in in situ and infiltrating tumours and in benign breast lesions by means of Western blotting and immunohistochemistry. The percentages of samples positive for IL-6, bcl-2 and bax and their immunoreaction densities were higher in in situ carcinomas and infiltrating tumours than in benign lesions; although in in situ lesions were not so high as in infiltrating tumours, except for bax, whose immunoexpression was as weak as in benign conditions, resulting in a bcl-2/bax ratio higher than in infiltrating tumours. CONCLUSIONS: The high expression of IL-6 and its receptors in tumours might be related to the enhanced cell proliferation occurring in breast cancer. IL-6 could act by increasing bcl-2 expression and thus altering the proliferation/apoptosis balance toward neoplastic cell proliferation. The increased bax immunoreactivity observed only in infiltrating tumours, which was not so high as the increase in bcl-2 immunoreactivity, might be interpreted as an attempt to hinder cell proliferation.

Adolescent↗

PubMed2004

Expression of ghrelin and its functional receptor, the type 1a growth hormone secretagogue receptor, in normal human testis and testicular tumors.

Ghrelin, the endogenous ligand for the GH secretagogue receptor (GHS-R), has been primarily linked to the central neuroendocrine regulation of GH secretion and food intake, although additional peripheral actions of ghrelin have also been reported. In this context, the expression of ghrelin and its cognate receptor has been recently demonstrated in rat testis, suggesting a role for this molecule in the direct control of male gonadal function. However, whether this signaling system is present in human testis remains largely unexplored. In this study we report the expression and cellular location of ghrelin and its functional receptor, the type 1a GHS-R, in adult human testis. In addition, evaluation of ghrelin and GHS-R1a immunoreactivity in testicular tumors and dysgenetic tissue is presented. The expression of the mRNAs encoding ghrelin and GHS-R1a was demonstrated in human testis specimens by RT-PCR, followed by direct sequencing. In normal testis, ghrelin immunostaining was demonstrated in interstitial Leydig cells and, at lower intensity, in Sertoli cells within the seminiferous tubules. In contrast, ghrelin was not detected in germ cells at any stage of spermatogenesis. The cognate ghrelin receptor showed a wider pattern of cellular distribution, with detectable GHS-R1a protein in germ cells, mainly in pachytene spermatocytes, as well as in somatic Sertoli and Leydig cells. Ghrelin immunoreactivity was absent in poorly differentiated Leydig cell tumor, which retained the expression of GHS-R1a peptide. In contrast, highly differentiated Leydig cell tumors expressed both the ligand and the receptor. The expression of ghrelin and GHS-R1a was also detected in dysgenetic Sertoli cell-only seminiferous tubules, whereas germ cell tumors (seminoma and embryonal carcinoma) were negative for ghrelin and were weakly positive for GHS-R1a. In conclusion, our results demonstrate that ghrelin and the type 1a GHS-R are expressed in adult human testis and testicular tumors. Overall, the expression of ghrelin and its functional receptor in human and rat testis, with roughly similar patterns of cellular distribution, is highly suggestive of a conserved role for this newly discovered molecule in the regulation of mammalian testicular function.

Adult↗

PubMed2004

Expression of vitamin D3 receptor and retinoid receptors in human breast cancer: identification of potential heterodimeric receptors.

Vitamin D3 (VD) and all-trans-retinoic acid (ATRA) have been postulated as a novel treatment option for breast carcinoma. Since the combined effects of retinoids and VD derivatives are attributed to heterodimeric interactions between members of the nuclear receptor family, the expression patterns of the heterodimers formed by vitamin D3 receptor (VDR) and the retinoid receptors RARs (RAR-alpha, RAR-beta and RAR-gamma) and RXRs (RXR-alpha, RXR-beta and RXR-gamma) have been studied by immunohistochemistry in benign and malignant breast tissues. Present results revealed that immunoexpressions to all receptor types studied were higher in both in situ and infiltrative carcinomas than in benign breast diseases. In a variable number of cases of infiltrative carcinoma, immunostaining appeared in the nucleus, whereas in the other two disorders immunostaining was only cytoplasmic. The correlation established between VDR and the different isoforms of retinoid receptors revealed that VDR seems to select mainly RAR-alpha to form heterodimers and to exert their properties as transcription factor. The results of this study suggest that this heterodimer plays a critical role in cancer malignancy, and its presence indicates those patient groups presenting a better response to adjuvant therapies based on the combination of vitamin D and ATRA.

Adult↗

PubMed2003

First immunocytochemical study of echinoderm smooth muscle: the Antarctic cushionstar Odontaster validus Koehler (Echinodermata, Asteroidea).

Our immunocytochemical observations reveal that the muscle present in the tips of the arms of the Antarctic cushionstar Odontaster validus contains caldesmon and calponin but not troponin. Thus, the muscle clearly belongs to the smooth muscle category. Distributions of contractile proteins such as actin, myosin (the latter a typical vertebrate muscle filament protein), paramyosin, and miniparamyosin (the latter two being characteristic of thick invertebrate muscle filaments) were also determined immunocytochemically. The results suggest that the thin filaments of the starfish smooth muscle are similar to those of the vertebrate muscle, but that the thick filaments differ from those of vertebrates and possess traits that are also seen in the muscle organization of invertebrates. The absence from the O. validus muscle of titin and nebulin, proteins so far known almost exclusively from the striated vertebrate muscle, comes as no surprise, but immunoreactivity to mini-titin (a protein of the same family as titin and its replacement in invertebrates) was strong and unambiguously recognizable between filaments. Odontaster validus' histochemical characteristics may be a reflection of the phylogenetic position of the echinoderms as deuterostome invertebrates or they may express an adaptation of the muscle to the harsh environmental conditions under which it has to function in the Antarctic water.

Actins↗

PubMed2003

Formation of multiple complexes between beta-dystroglycan and dystrophin family products.

Beta-dystroglycan is expressed in a wide variety of tissues and has generally been reported with an Mr of 43 kDa, sometimes accompanied with a 31 kDa protein assumed to be a truncated product. This molecule was recently identified as the anomalous beta-dystroglycan expressed in various carcinoma cell lines. We produced and characterized a G5 polyclonal antibody specific to beta-dystroglycan that is directed against the C-terminal portion of the molecule. We provide evidence that beta-dystroglycan may vary in size and properties by studying different Xenopus tissues. Besides normal beta-dystroglycan with an Mr of 43 kDa in smooth and cardiac muscle and sciatic nerve extracts, we found it in skeletal muscle and brain proteins with an Mr of 38 and 65 kDa, respectively. Glycosylation properties and proteolytic susceptibilities of these different beta-dystroglycans are analysed and compared in this work. Crosslinking experiments with various beta-dystroglycan preparations obtained from skeletal and cardiac muscles and brain gave rise to specific new covalent products with Mr of 125 kDa (doublet band), or 120 and 130 kDa, or 140 and 240 kDa, respectively. We provide evidence, using various similar beta-dystroglycan preparations, that the immunoprecipitation procedure with G5 specific polyclonal antibody allows consistent pelleting of various dystrophin-family isoforms. Skeletal muscles from Xenopus reveals the presence of two distinct beta-dystroglycan complexes, one with dystrophin and another one which involves alpha-dystrobrevin. Cardiac muscle and brain from Xenopus are shown to contain three beta-dystroglycan complexes related to various dystrophin-family isoforms. Dystrophin or alpha-dystrobrevin or Dp71 were found in cardiac muscle and dystrophin or Dp180 or Up71 in brain. This variability in the relationship between beta-dystroglycan and dystrophin-family isoforms suggests that each protein--currently known as dystrophin associated protein--could not be present in each of these complexes.

Animals↗

PubMed2003

Dystrophin and dystrophin-associated protein in muscles and nerves from monkey.

Since all organs (i.e. skeletal, cardiac, smooth muscles and sciatic nerve) are never only taken from a single patient, all these tissues were obtained from one cynomolgus monkey, a model closely resembling humans. This work describes an up-to-date reinvestigation of the dystrophin-glycoprotein complex and related molecules in various monkey tissues such those cited above. We used monoclonal and polyclonal antibodies produced in our laboratory, which are directed against dystrophin, utrophin, short-dystrophin products, alpha-dystrobrevin, beta-dystroglycan, alpha-syntrophin, alpha-, beta-, gamma-, delta-, epsilon-sarcoglycan, and sarcospan. For each molecule, we determined their molecular weight and tissue localization. Regardless of the tissue analyzed, at least one dystrophin or utrophin as full-length molecule and one short-dystrophin product or dystrobrevin as proteins belonging to the dystrophin superfamily were found. Beta-dystroglycan, beta and delta sarcoglycans were always detected, while other sarcoglycans varied from all to only three components. Epsilon sarcoglycan appears to be specific to smooth muscle, which is devoid of alpha sarcoglycan. Sarcospan is only absent from sciatic nerve structures. Among the different muscles investigated in this study, short dystrophin products are only present in cardiac muscle. All of these findings are summarized in one table, which highlight in one single animal the variability of the dystrophin-glycoprotein complex components in relation with the organ studied. This statement is important because any attempt to estimate protein restoration needs in each study the knowledge of the expected components that should be considered normal.

Animals↗

PubMed2002

Immunohistochemical detection of the retinoid acid receptors (RXR-alpha, -beta, -gamma) and Farnesoid X-activated receptor (FXR) in the marbled newt along the annual cycle.

Retinoid acid receptors (RXR-alpha, -beta, -gamma) and Farnesoid X-activated receptor (FXR) expression in the testis of the marbled newt were investigated with special attention to the changes during the annual testicular cycle, using light microscopy immunohistochemistry and Western blot analysis. The annual testicular cycle of the marbled newt (Triturus marmoratus marmoratus) comprises three periods: (a) proliferative period (germ cell proliferation from primordial germ cells to round spermatids, April-June); (b) spermiogenesis period (July-September); and (c) quiescence period (interstitial and follicular cells form the glandular tissue, October-April). In the proliferative period, primordial germ cells and primary spermatogonia immunostained intensely to the three types of RXRs and also to FXR. In the other periods, immunostaining to these antibodies was weak or absent. Secondary spermatogonia stained weakly to the four antibodies in the proliferative period, and only to FXR, also weakly, in the spermiogenesis period. Immunoreactive primary spermatocytes were weakly labeled with the RXR antibodies in the proliferative period. Spermatids and spermatozoa did not stain to any antibody in any period. Follicular cells only immunostained to RXR-gamma and only in the quiescence period when they are forming the glandular tissue, together with the interstitial cells. As follicular cells, interstitial cells only immunostained in the quiescence period; however, they immunoreacted to the three types of RXRs. These findings suggest that in the newt, RXRs and FXR are involved in spermatogenesis control by regulating the proliferation of primordial germ cells and spermatogonia. In addition, RXR-gamma seems to be also involved in the development of the glandular (steroidogenic) tissue.

Animals↗

PubMed2001

Cadmium chloride-induced dysplastic changes in the ventral rat prostate: an immunohistochemical and quantitative study.

BACKGROUND: Cadmium chloride is an environmental toxic that might be implicated in human prostate carcinogenesis. The study was directed: 1) to evaluate the immunoexpression of markers for cell proliferation, apoptosis, and resistance to apoptosis, and 2) to estimate the size of premalignant cell population in the preneoplastic changes induced in ventral prostates of rats treated with cadmium chloride administered in drinking water. METHODS: The following parameters were calculated in the ventral prostatic lobe of normal rats and rats that received cadmium in drinking water during 18 months: total volume, epithelial volume, total number of epithelial cells, numerical density of epithelial cells, percentage of cells that immunostained to the proliferating cell nuclear antigen (PCNA), percentage of apoptotic cells (evaluated by a DNA fragmentation method), and absolute volume and volume fraction of immunostaining to bcl-2. RESULTS: The percentage of PCNA immunoreactive nuclei, the bcl-2 expression, and the numerical density of epithelial cells were significantly (P < 0.05) increased in the dysplastic prostatic acini of treated rats in comparison with the normal acini of treated rats and control animals. The percentage of apoptotic nuclei from ventral dysplastic acini was significantly (P < 0.05) decreased in comparison with that of normal acini. A negative correlation between proliferation and apoptosis was found in dysplastic lesions. CONCLUSIONS: Prostate epithelial dysplasia induced in rats by cadmium presents an increased proliferative activity and high expression of bcl-2 protein, as was described in human prostate intraepithelial neoplasia. However, the rate of apoptosis in rat dysplasia was importantly decreased, in contrast to that observed in some human preneoplastic changes. This decrease might be related to the increase of bcl-2 expression.

Administration, Oral↗

PubMed2001

Smooth muscle proteins as intracellular components of the chromatophores of the Antarctic fishes Pagothenia borchgrevinki and Trematomus bernacchii (Nototheniidae).

Melanophores, xanthophores, and iridophores from the skins of the two Antarctic fish species Pagothenia borchgrevinki and Trematomus bernacchii were tested immunocytochemically for the presence of a variety of muscle proteins. Actin, myosin, and calmodulin, not surprisingly, were confirmed for all three chromatophore types of the two fishes, but the presence of caldesmon and calponin, both characteristic proteins of smooth muscle fibers, represents a new discovery. It is not known at this stage whether these proteins occur also in the chromatophores of other fishes and are not restricted to Antarctic species. Since, however, motility control of particles in fish chromatophores and the regulation of smooth muscle tension both involve the sympathetic nervous system, the presence of similar target proteins should not come as a surprise. The fact that none of the chromatophores tested positive for troponin shows that there is no close relationship between pigment cells and striated muscle. The lack of alpha-actinin in iridophores, but its presence in melanophores and xanthrophores, is thought to be a reflection of the considerably greater pigment translocations within the latter two types of chromatophore cells.

Animals↗

PubMed2001

Dystrophin-associated proteins in obliquely striated muscle of the leech Pontobdella muricata (Annelida, Hirudinea).

The distribution of dystrophin-associated proteins (beta-dystroglycan, alpha-, beta-, gamma- and delta-sarcoglycan, alpha-syntrophin and sarcospan) were studied in obliquely striated muscle of the leech Pontobdella muricata. Western blot analysis and immunohistochemical electron microscopy, using various polyclonal antibodies, were employed. Western blot analysis of all of these antibodies showed a single band, with approximately the same molecular weights as similar proteins detected in vertebrate muscles. The immunoelectron microscopy study confirmed specific immunogold labelling in the membrane of muscle cells. Since all dystrophin complex components have similar molecular weights and the same localisation in leech as in vertebrate skeletal muscle, we assume that these proteins have similar properties in leech and vertebrate muscle. The presence of these molecules in annelid muscles, together with a short version of dystrophin (previously described as IDLp-140) is of particular interest since phylogenetic and functional studies on this material could help to shed new light on the role and function of this complex in the muscle membrane.

Animals↗

PubMed2001

Lipomembranous fat necrosis in three cases of testicular torsion.

AIMS: To describe for the first time a lesion termed lipomembranous fat necrosis (LFN) in three patients with spermatic cord torsion. METHODS AND RESULTS: We reviewed 386 testes and their epididymides and spermatic cords which had been removed for testicular infarction. For the three cases showing LFN, a battery of histochemical tests (including periodic acid-Schiff (PAS), orcein, Sudan black and Perls stains) was applied and clinical histories and laboratory data were also investigated. Findings were similar in the three specimens. The testes showed a central group of necrotic seminiferous tubules which were surrounded by granulation tissue consisting of macrophages, multinucleated giant cells, lymphocytes, plasma cells and fibrous connective tissue at the periphery of the lesion. The spermatic cord showed thrombosed veins surrounded by fat necrosis showing cystic cavities which were bounded by wavy hyaline membranes. These stained with Sudan black, PAS (before and after diastase digestion) and orcein and presented yellowish-green autofluorescence. CONCLUSIONS: Lipomembranous fat necrosis of the spermatic cord is a distinctive entity which seems to be related to spermatic cord torsion and the differential diagnosis of which should be established with regard to the presence of parasites, sclerosing lipogranuloma and granuloma evoked by rupture of a testicular prosthesis.

Adipose Tissue↗

PubMed2001

Morphometric evaluation of the human prostate.

In order to clarify the ageing-related histological changes in the human prostate, a quantitative morphometric analysis was performed. Complete prostates were obtained at autopsy from 281 men (aged 20-84 years) who died in traffic accidents and presented no clinical symptoms of prostatic disease. The prostates were classified as: histologically normal (n=182), with nodular hyperplasia (n=42), with intraepithelial neoplasia (n=40) and carcinomatous with low Gleason grade (n=20). Each prostate was divided into three regions (periurethral, central and peripheral) and the volume of each region, as well as the average volume occupied by stroma and epithelium in each region were quantified. For each parameter, the average values for each age group were compared. In the histologically normal prostates, an increase with ageing in the total volume and the volume occupied by the central region were observed; these increases were mainly caused by an increase in the stromal volume of the central region in men after 30 years of age. No histologically normal prostates were found in men older than 70 years of age. Nodular prostatic hyperplasia was found in men over 30 years of age and a fluctuation in the total volume throughout ageing was observed. Prostates with intraepithelial neoplasia (PIN) and carcinoma were observed in men aged >20 years and the total volume and those of each prostatic region showed multiple variations, except for the eighth decade where a marked increase with regard to that of the previous decades was observed.

Adult↗

PubMed2001

Androgen receptor (AR), estrogen receptor-alpha (ER-alpha) and estrogen receptor-beta (ER-beta) expression in the testis of the newt, Triturus marmoratus marmoratus during the annual cycle.

Expression of androgen receptor (AR), estrogen receptor alpha (ER-alpha) and estrogen receptor beta (ER-beta) in the testis of the marbled newt (Triturus marmoratus marmoratus) was investigated, with special attention to changes during the annual testicular cycle, using light microscopy immunohistochemistry and Western blot analysis. Primordial germ cells, primary and secondary spermatogonia and spermatocytes showed a positive reaction to the 3 receptor antibodies during the annual reproductive cycle. Follicular cells were positive to AR, ER-alpha and ER-beta during the spermiogenesis and quiescence periods in the glandular tissue. Interstitial cells showed reactivity to AR, ER-alpha and ER-beta in the spermiogenesis and the quiescence periods, and presented no labelling to these receptors in the proliferative period. These findings suggest that, as in mammals, there is an androgen-estrogen regulation of the function and development of the newt testis.

Animals↗

PubMed2001

Staphylococcal peritonitis in continuous ambulatory peritoneal dialysis: colonization with identical strains at exit site, nose, and hands.

To evaluate the relationship of nasal or skin Staphylococcus carrier status with identical strains and the development of staphylococcal peritonitis, 59 consecutive peritonitis episodes in patients using a twin-bag system for continuous ambulatory peritoneal dialysis from a single dialysis center were prospectively studied. Dialysate samples and exit-site, nose, and nail swabs from patients and their dialysis partners were obtained on the same day for culture. When bacteria belonging to the same species of the Staphylococcus genus were isolated from dialysate and at least one extraperitoneal anatomic site, pulsed-field gel electrophoresis typing was performed. The bacterial strains isolated from catheter exit site, nose, or nails of each patient and his or her dialysis partner were classified as identical or different. Twenty-seven of the 59 peritonitis episodes (46%) were caused by staphylococci. Nineteen of these 27 patients carried the same Staphylococcus species causing the peritonitis episode at the exit site, nose, or nails, but only 17 patients (63%) carried an identical strain. Four of 5 dialysis partners carried the same Staphylococcus species causing the peritonitis episode at nose or nails, but the strain was identical for only 3 dialysis partners (60%). Four patients and 1 dialysis partner carried unrelated strains of the Staphylococcus species causing the peritonitis episode. The most frequently colonized site with strains identical to that causing the peritonitis episode was the catheter exit site, followed by nose and nails. This finding may be clinically relevant because eradication of Staphylococcus aureus colonizing the catheter exit site may be more important and have a greater likelihood of success than maneuvers directed to more distant locations.

Carrier State↗