Biomedical subjects

A Paz

Publications and source records attributed to A Paz.

At least 37 records · Page 2Linked to original sources

PubMed2000

Protein kinase C (PKC) isoenzymes immunohistochemistry in lymph node revealing solution-fixed, paraffin-embedded bladder tumors.

Protein kinase C (PKC) plays an important role in cellular differentiation and in the malignant process. In an earlier study, it was shown that the expression pattern of PKC isoenzymes is altered in some tumors compared to their corresponding normal tissue. In this study, we evaluated the pattern of PKC isoenzyme immunostaining in bladder transitional cell carcinoma (TCC) of different grades and stages and normal tissue. Twenty-seven TCC samples and six areas of normal bladder mucosa were stained with antibodies specific for the PKC isoenzymes: alpha, beta 1, beta 2, delta, and zeta. The sections were scored for intensity of staining, and the correlation with grade and stage of the tumors was computed. The PKC alpha and beta 2 immunostains were intense in normal urothelium and in all evaluated tumors. PKC beta 1 and delta stains were intense in normal and low-grade and -stage tumors and weak in high-grade and -stage tumors. The opposite trend was found for PKC zeta. PKC isoenzyme expression differs in invasive TCC compared to low-grade, low-stage TCC and normal urothelium. The value of these findings as a marker of tumor aggressiveness should be further assessed.

Aged↗

PubMed2000

Influence of internal and environmental factors on the distribution and occurrence of Hypoderma (Diptera: Oestridae) in cattle in Galicia (northwest of Spain).

This study establishes the seroprevalence of Hypoderma spp in cattle and the influence of some internal and environmental factors in the distribution of this myiasis in Galicia (northwest of Spain). Humoral antibody levels were measured by means of an indirect enzyme-linked immunosorbet assay, using as the antigen hypodermin C obtained from 1st-instar Hypoderma lineatum (De Villers). The percentage of positive sera in the total sample of 1,473 animals was 78.4%. Considering the different climatic areas in Galicia, the seroprevalence was lower in coastal areas; whereas, in the inland the percentages of positive sera were higher. The study revealed significant differences in seroprevalence between breeds; the autochthonous Rubia Gallega breed was the most prevalent, followed by the crossbreeds Brown Swiss and Friesian. The breeding system was an important factor affecting the occurrence of hypodermosis.

Animals↗

PubMed1999

Targeting of K-Ras 4B by S-trans,trans-farnesyl thiosalicylic acid.

Ras proteins regulate cell growth, differentiation and apoptosis. Their activities depend on their anchorage to the inner surface of the plasma membrane, which is promoted by their common carboxy-terminal S-farnesylcysteine and either a stretch of lysine residues (K-Ras 4B) or S-palmitoyl moieties (H-Ras, N-Ras and K-Ras 4A). We previously demonstrated dislodgment of H-Ras from EJ cell membranes by S-trans,trans-farnesylthiosalicylic acid (FTS), and proposed that FTS disrupts the interactions between the S-prenyl moiety of Ras and the membrane anchorage domains. In support of this hypothesis, we now show that FTS, which is not a farnesyltransferase inhibitor, inhibits growth of NIH3T3 cells transformed by the non-palmitoylated K-Ras 4B(12V) or by its farnesylated, but unmethylated, K-Ras 4B(12) CVYM mutant. The growth-inhibitory effects of FTS followed the dislodgment and accelerated degradation of K-Ras 4B(12V), leading in turn to a decrease in its amount in the cells and inhibition of MAPK activity. FTS did not affect the rate of degradation of the K-Ras 4B, SVIM mutant which is not modified post-translationally, suggesting that only farnesylated Ras isoforms are substrates for facilitated degradation. The putative Ras-recognition sites (within domains in the cell membrane) appear to tolerate both C(15) and C(20) S-prenyl moeities, since geranylgeranyl thiosalicylic acid mimicked the growth-inhibitory effects of FTS in K-Ras 4B(12V)-transformed cells and FTS inhibited the growth of cells transformed by the geranylgeranylated K-Ras 4B(12V) CVIL isoform. The results suggest that FTS acts as a domain-targeted compound that disrupts Ras-membrane interactions. The fact that FTS can target K-Ras 4B(12V), which is insensitive to inhibition by farnesyltransfarase inhibitors, suggests that FTS may target Ras (and other prenylated proteins important for transformed cell growth) in an efficient manner that speaks well for its potential as an anticancer therapeutic agent.

3T3 Cells↗

PubMed1999

Molecular cloning and structural and functional characterization of human cathepsin F, a new cysteine proteinase of the papain family with a long propeptide domain.

A cDNA encoding a new cysteine proteinase belonging to the papain family and called cathepsin F has been cloned from a human prostate cDNA library. This cDNA encodes a polypeptide of 484 amino acids, with the same domain organization as other cysteine proteinases, including a hydrophobic signal sequence, a prodomain, and a catalytic region. However, this propeptide domain is unusually long and distinguishes cathepsin F from other proteinases of the papain family. Cathepsin F also shows all structural motifs characteristic of these proteinases, including the essential cysteine residue of the active site. Consistent with these structural features, cathepsin F produced in Escherichia coli as a fusion protein with glutathione S-transferase degrades the synthetic peptide benzyloxycarbonyl-Phe-Arg-7-amido-4-methylcoumarin, a substrate commonly used for functional characterization of cysteine proteinases. Furthermore, this proteolytic activity is blocked by trans-epoxysuccinyl-L-leucylamido-(4-guanidino)butane, an inhibitor of cysteine proteinases. The gene encoding cathepsin F maps to chromosome 11q13, close to that encoding cathepsin W. Cathepsin F is widely expressed in human tissues, suggesting a role in normal protein catabolism. Northern blot analysis also revealed a significant level of expression in some cancer cell lines opening the possibility that this enzyme could be involved in degradative processes occurring during tumor progression.

Amino Acid Sequence↗

PubMed1999

Subclass profile of specific IgG antibodies in rats challenged during acute and chronic primary infection with Fasciola hepatica.

The influence of a previous infection (acute and chronic) on the kinetics of the immune humoral response in rats challenged with Fasciola hepatica was studied. Two infected groups were reinfected at different times--one, at 4 weeks after primary infection (w.a.p.i.); and the other, at 11 w.a.p.i. Signs of reinfection were observed in the two challenged groups as evidenced by an increment in glutamate dehydrogenase and gamma-glutamyl transpeptidase activity after secondary infection. IgG subclass (IgG1, IgG2a, IgG2b, IgG2c) responses to F. hepatica excretory/secretory products (FhESP) differed, depending on the time of challenge infection, but no difference was observed between the reinfected groups. A predominance of the IgG1 subclass was noted in the group challenged at 4 w.a.p.i., and IgG2b and IgG2c were prominent in the group reinfected at 11 w.a.p.i. These results indicate that the presence of juvenile or adult flukes in the liver at the time of challenge seems to influence the immune response to a secondary infection.

Acute Disease↗

PubMed1999

Lymph node revealing solution: a rapid method for the fixation of cystectomy specimens.

The objective of this study was to describe the use of the lymph node revealing solution (LNRS) for rapid fixation of total cystectomy specimens, and to compare it with formalin fixation. LNRS is a mixture of 95% ethanol, diethyl ether, glacial acetic acid and buffered formalin (65:20:5:10 v/v) prepared under a fume-hood. Sixteen consecutive cystectomy specimens were fixed for two hours either in LNRS or in buffered formalin. Representative sections were embedded in paraffin, sectioned and stained with H&E, periodic acid Schiff, alcian-blue, and immunostained for cytokeratins 20, high and low molecular weight cytokeratins, prostatic specific antigen, Factor VIII related antigen, s-100 protein, and protein kinase C isoenzymes. Results showed that the tissues were well fixed after 2 hours in LNRS, and were not fixed after 2 hours in formalin. Processing and sectioning of the paraffin blocks of the LNRS fixed tissue was excellent; it was impossible in the sections fixed for 2 hours in formalin. All the stains were excellent after LNRS fixation. We conclude that fixation of cystectomy specimens in LNRS requires only two hours and results in excellent stained slides. It is therefore recommended for cystectomy specimens.

Biomarkers, Tumor↗

PubMed1999

Twenty-four-hour oscillations of facial electroneurography parameters and their relationship to body temperature.

The purpose of the present study was to assess the temporal variation of the facial electroneurography (ENoG) parameters recorded from the nasolabial crease and to compare it to the temporal oscillations of oral and facial cutaneous temperatures. Twelve healthy individuals were examined at 4-hour intervals for 2 consecutive days. Twenty-four-hour rhythms of oral and facial cutaneous temperatures were found in all subjects (troughs on average at 4:20 and 4:00 AM, respectively). Significant 24-hour oscillations of ENoG amplitude were found in all subjects, which were positively correlated to the oscillations of oral and facial cutaneous temperatures (trough on average at 2:40 AM). The compound action potential (CAP) latency fluctuated during the day and was negatively correlated with local temperatures. However, these fluctuations and correlations did not reach statistical significance. We also found a significant reduction of ENoG amplitude in 5 patients with artificial cooling of the face near the facial nerve. Also, there was a small increase in CAP latency with facial cooling. Interpreting ENoG recordings in accordance with oral temperature and recording time of day reduce the intertest variation.

Action Potentials↗

PubMed1999

Double-phase 99mTc-sestamibi scintimammography and trans-scan in diagnosing breast cancer.

UNLABELLED: The goal of our study was to assess the value of both scintimammography with 99mTc-sestamibi (SMM) and trans-scan (T-scan) in detecting breast cancer. METHODS: A total of 121 women were evaluated by palpation, mammography, SMM and T-scan. SMM was performed in the prone, breast dependent position. Immediate and delayed views (double-phase) were obtained. T-scan is a new breast imaging method that maps noninvasively the distribution of tissue electrical impedance and capacitance. RESULTS: SMM had 88.9% sensitivity, 88.4% specificity and 88.4% accuracy in detecting breast cancer. SMM had 100% sensitivity in detecting breast tumors >1 cm and only 66% sensitivity in detecting tumors <1 cm. T-scan had 72.2% sensitivity and 67% specificity in detecting breast cancer. It detected one more breast cancer than SMM, at the expense of 27 additional false-positive results. CONCLUSION: Double-phase SMM was sensitive and specific in detecting breast cancer. This method may reduce the rate of negative breast biopsies in tumors >1 cm. T-scan was only moderately accurate in detecting breast cancer. Its addition to SMM did not improve significantly the rate of breast cancer detection. However, because of its complete noninvasiveness, large-scale applicability and low cost, T-scan deserves further refining.

Adult↗

PubMed1999

Development, characterization, and use of monoclonal antibodies made to antigens expressed on the surface of fetal nucleated red blood cells.

BACKGROUND: Current methods for obtaining fetal cells for prenatal diagnosis are invasive and carry a small (0.5-1.0%) but definite risk of miscarriage. An attractive alternative would be isolation of fetal cells from peripheral maternal blood using antibodies with high specificity and avidity. METHODS: To generate antibodies, we purified nucleated red blood cells (NRBCs) from fetal livers and used them as the immunogen to generate monoclonal antibodies (mAbs) directed against surface antigens. RESULTS: The four antibodies recognized at least two conformationally sensitive epitopes of the transferrin receptor. Isolation of NRBCs from 252 maternal blood samples using these antibodies in magnetic activated cell sorting after an initial density gradient centrifugation yielded 0-419 NRBCs per 25 mL of maternal blood. One antibody, 2B7.4, not only isolated the highest number of NRBCs (>10 in 90% of the samples) but also isolated these NRBCs in 78 consecutive maternal samples. CONCLUSION: Antibody 2B7.4 shows promise for the isolation of NRBCs from maternal blood and should allow studies concerning the source of these cells, fetal vs maternal, and the factors controlling their prevalence.

Animals↗

PubMed1998

IgG isotype specific immune response in rats infected with Fasciola hepatica.

Antibody responses (IgG1, IgG2a, IgG2b, and IgG2c subclasses) against Fasciola hepatica L. in rats infected with metacercariae were analysed by ELISA. Animals of group 1 (R-1) remained infected throughout 21 weeks, and rats of group 2 (R-2) received a single oral dose of triclabendazole (Fasinex 10%, Ciba-Geigy) at 4 weeks after infection. Group C (R-C) consisted of rats left intact which served as uninfected controls. All IgG subclasses increased during the first weeks after infection, but when triclabendazole was administered IgG1 and IgG2b diminished markedly. IgG2c showed a different profile to the other antibodies evaluated, increasing earliest and decreasing profoundly from the 9-11th week after infection (w.a.i). The infected-untreated rats produced higher titres of antibodies than the rats of R-2, and these differences were statistically significant (p < 0.05) in all subclasses evaluated except in IgG2a titres.

Animals↗

PubMed1998

Dislodgment and accelerated degradation of Ras.

Membrane anchorage of Ras oncoproteins, required for transforming activity, depends on their carboxy-terminal farnesylcysteine. We previously showed that S-trans,trans-farnesylthiosalicylic acid (FTS), a synthetic farnesylcysteine mimetic, inhibits growth of ErbB2- and Ras-transformed cells, but not of v-Raf-transformed cells, suggesting that FTS interferes specifically with Ras functions. Here we demonstrate that FTS dislodges Ras from membranes of H-Ras-transformed (EJ) cells, facilitating its degradation and decreasing total cellular Ras. The dislodged Ras that was transiently present in the cytosol was degraded relatively rapidly, causing a decrease of up to 80% in total cellular Ras. The half-life of Ras was 10 +/- 4 h in FTS-treated EJ cells and 27 +/- 4 h in controls. The dislodgment of membrane Ras and decrease in total cellular Ras were dose-dependent: 50% of the effects occurred at 10-15 microM, comparable to concentrations (7-10 microM) required for 50% growth inhibition in EJ cells. Higher concentrations of FTS (25-50 microM) were required to dislodge Ras from Rat-1 cell membranes expressing normal Ras, suggesting some selectivity of FTS toward oncogenic Ras. Membrane localization of the prenylated G beta gamma of heterotrimeric G proteins was not affected by FTS in EJ cells. An FTS-related compound, N-acetyl-S-farnesyl-L-cysteine, which does not inhibit EJ cell growth, did not affect Ras. FTS did not inhibit growth of Rat-1 cells transformed by N-myristylated H-Ras and did not reduce the total amount of this Ras isoform. The results suggest that FTS affects docking of Ras in the cell membrane in a rather specific manner, rendering the protein susceptible to proteolytic degradation.

Acetylcysteine↗

PubMed1998

Subclasses of IgG in different aged rats with fasciolosis.

The variations in antibody responses (total IgG and IgG1, IgG2a, IgG2b, and IgG2c subclasses) were studied in two groups of rats infected with metacercariae of the trematode Fasciola hepatica L. Animals of group 1 were 4 weeks old, and rats of group 2 were 13 weeks old. All IgG subclasses increased during the course of infection except IgG2c, which decreased. The younger rats reached more marked responses than the older, at least during the period of this trial. IgG1 and IgG2a antibodies reached the highest levels, and among these two, IgG2a response was slightly superior to IgG1.

Age Factors↗

PubMed1998

Atypical microangiopathy in a patient treated with ticlopidine.

Microangiopathies are rare complications during treatments with ticlopidine. We describe an atypical microangiopathy, affecting almost exclusively myocardium, and thrombocytopenia, shortly after onset of ticlopidine. The patient died a few days after. Autopsy showed no bleedings or large thrombi in most organs, but were compatible with microangiopathy in myocardial small vessels.

Humans↗

PubMed1998

Comparison of radionuclide scrotal blood-pool index versus gonadal venography in the diagnosis of varicocele.

UNLABELLED: The purpose of our study was to assess the value of a radionuclide scrotal blood-pool index (SBPI) in diagnosing and grading clinical and subclinical varicocele. METHODS: Scrotal scans were performed on 1360 infertile patients. Thirty fertile patients with a normal scrotum on palpation served as controls. The patients' red blood cells were labeled in vivo by administration of stannous ions of pyrophosphate followed by the intravenous administration of 99Tc-pertechnetate. The scans initially were inspected visually and, when bilateral varicocele was excluded, a computerized analysis of the ratio of the blood-pool activity in each hemiscrotum (SBPI) permitted accurate grading of the varicocele. A subgroup of 224 patients was selected randomly and had gonadal venography. The results of physical examination, scrotal scan, gonadal venography and semen analysis were compared. RESULTS: Normal values of SBPI (0.9-1.1) were derived from the control group. There was a 93.5% correlation between palpation and SBPI grade in diagnosing palpable varicocele. When compared to gonadal venography, subclinical varicocele was demonstrated by scrotal scan in 54.8% of infertile male patients with abnormal semen analysis, normal female partners and no other cause of infertility. Of these patients, 32.6% had, unexpectedly, Grade 2 or 3 varicocele. Right and bilateral varicocele were demonstrated three times as often by scrotal scan than by palpation. SBPI was accurate in diagnosing recurrent varicocele but there was a low correlation (61.1%) between SBPI and gonadal venography grade. There was a high correlation between SBPI grade and sperm analysis grade. CONCLUSION: SBPI grading of varicocele was validated as an accurate, quantitative and noninvasive method of grading varicocele, equivalent to the grading system by palpation in a large group of infertile patients. The main contribution of SBPI was in detecting and grading subclinical varicocele in infertile patients with no other cause of infertility. SBPI also was accurate in diagnosing but not in grading recurrent varicocele.

Adolescent↗

PubMed1997

The role of external sphincterotomy for patients with a spinal cord lesion.

For the last three decades external sphincterotomy has been well accepted as a treatment for bladder outlet obstruction in patients with a spinal cord lesions. Recently, however, its value has been brought into question. To assess the current place of this procedure in the treatment of the neuropathic bladder of spinal origin, we studied the outcomes of sphincterotomy in 32 patients. Post-voiding residual urine volume decreased after surgery in 27 patients (84%), considerably in 22 (69%) of them. Clinical infection resolved in 14 out of 19 patients (74%), hydronephrosis disappeared in two out of three (66%), and vesicourethral reflux improved in three out of five (60%) and was cured in two (40%). Six of the patients (19%) were freed from catheterization, but two patients (6%) lost partial continence. Sphincterotomy is an important tool in the treatment of spinal patients with bladder outlet obstruction and should be considered when the proper indications exist.

Adult↗

PubMed1997

The clinical and histological features of transitional cell carcinoma of the bladder with microcysts: analysis of 12 cases.

OBJECTIVE: To describe the clinical course and histological features of transitional cell carcinoma (TCC) of the bladder with microcysts. PATIENTS AND METHODS: Among 940 patients with bladder TCC diagnosed at our institution during a 5 year period. 12 (1.2%; eight men and four women, mean age 71.1 years, range 52-85) were diagnosed histologically as having microcystic TCC. Sections of the tumours were stained with haematoxylin and eosin, periodic acid-Schiff and Alcian blue and clinical data obtained from the patients' records. RESULTS: Of the 12 patients with bladder TCC with microcysts, three had tumours confined to the epithelium, six had tumour invasion of the lamina propria and three had muscle invasion. One patient had low-grade TCC and 11 had high-grade TCC; six patients had a second primary tumour; three had a colon carcinoma, one a villous adenoma of the caecum, one a locally advanced carcinoma of the prostate and the last a squamous cell carcinoma of the uterine cervix. CONCLUSIONS: Microcystic TCC was associated with high-stage and high-grade bladder tumours and with other primary tumours, especially of the colon. Screening these patients for asymptomatic tumours of the colon is suggested.

Aged↗

PubMed1997

Lymph-node revealing solution: a new method for detecting minute lymph nodes in cystectomy specimens.

OBJECTIVE: To describe the use of a new lymph-node revealing solution (LNRS) for detecting lymph node involvement in total cystectomy specimens from patients with locally confined invasive transitional cell carcinoma (TCC) of the bladder, and to compare the results obtained with those using the conventional method (palpation and sectioning perivesical fat) that may fail to detect very small lymph nodes. MATERIALS AND METHODS: Of 12 cystectomy specimens obtained from patients with TCC, six in which 0-3 metastatic nodes were identified by the conventional method were further investigated using LNRS. The revealing solution comprised 95% ethanol, diethyl ether, glacial acetic acid and buffered formalin (65:20:5:10 v/v) prepared under a fume-hood. After evaluation using the conventional method, the specimens were immersed for 6-12 h in the solution, washed under running tap water and the adipose tissue sectioned at intervals of 2-3 mm. Lymph nodes were identified as white, chalky nodules against the background of yellow fat. The number of the lymph nodes identified by conventional and the LNRS methods was recorded and classified according the TNM system. RESULT: Twenty-two lymph nodes were detected by the conventional method, of which four were positive for tumour metastasis. Using the LNRS, an additional 21 nodes were identified among which 12 were positive. The mean size of the lymph nodes detected by the conventional and LNRS methods was 7.96 mm and 3.81 mm, respectively. The stage of three patients was increased (Nx to N2, N0 to N2 and N1 to N2) and therefore two of these patients received adjuvant chemotherapy. CONCLUSIONS: LNRS significantly enhanced the yield of normal and metastatic nodes of cystectomy specimens and may identify smaller nodes. The LNRS method allows a more accurate staging with better assessment of the prognosis and need for adjuvant therapy.

Carcinoma, Transitional Cell↗

PubMed1997

Lymph node revealing solution: a new method for detection of minute axillary lymph nodes in breast cancer specimens.

The staging and prognosis of patients with breast cancer is related to the presence or absence of axillary lymph node involvement. However, in some cases no lymph nodes or too small a number of lymph nodes are revealed by the traditional method of palpating and sectioning the axillary fat. In the present study we demonstrate the usefulness of the lymph node revealing solution (LNRS) in breast cancer. Specimens from 13 patients, in whom <10 lymph nodes were identified in the axilla by the traditional method, were included in the study. After excising the lymph nodes by the traditional method, axillary tissue was immersed in LNRS for 6-12 hours. Additional lymph nodes, which stood out as white chalky nodules, were excised and processed as usual. The LNRS increased the mean number of nodes per case from 6.0+/-2.5 found by the traditional method to 12.54+/-4.61 nodes per case (p < 0.01). The size of the nodes identified by the LNRS was significantly smaller (p < 0.01) than those detected by the traditional method. The LNRS changed the lymph node stage of the disease in four of the studied cases (30%). LNRS seems to be the technique of choice for detection of axillary lymph nodes in cases where the number of detected lymph nodes by the traditional method is too small for accurate staging.

Axilla↗