Search PubMed⌕ Search

Biomedical subjects

J Navarro

Publications and source records attributed to J Navarro.

At least 289 records · Page 16Linked to original sources
PubMed1991

The effect of artificial feeding on cholestasis, gallbladder sludge and lithiasis in infants: correlation with plasma cholecystokinin levels.

The occurrence of hepatic cholestatis (judged by fasting serum bile acid levels), gallbladder sludge formation and lithiasis (ultrasonography) and their correlation with plasma cholecystokinin (CCK) levels was studied in a group of children on continuous total parenteral nutrition (TPN) (n = 95), and later in 40 of these children on cyclic TPN (cTPN). After resumption of oral feeding, 75 were studied on partial oral feeding (2-4 meals) and 40 on constant rate enteral nutrition (CREN) then 45 on total oral feeding (4-6 meals). Gallbladder sludge occurred in 23% of the children on TPN for 1 month and 32% of those on cTPN for 3 months. On CREN, the sludge rate was unchanged, but dropped significantly (17%) on partial oral feeding, and disappeared in children on total oral feeding. Serum bile acids were abnormal in 80% of children on TPN or cTPN and diminished significantly on total oral feeding only. Plasma CCK levels on TPN, cTPN and CREN were identical to fasting levels of children on total oral feeding. Plasma CCK levels increased significantly 1 h post-prandially during both partial (p < 0.02) and total oral feeding (p < 0.001). There was a significant negative correlation between the gallbladder sludge rate and CCK levels for all methods of feeding. This study demonstrates the frequent occurrence of hepatic cholestasis in infants, and the much lower frequency of gallbladder sludge in children compared to adults on TPN. Plasma CCK levels obtained during the different methods of feeding could explain the reduction and eventual disappearance of sludge following stimulation of CCK secretion by discontinuous feeding.

Journal Article↗
PubMed1991

Chromosome abnormalities in human spermatozoa after albumin or TEST-Yolk capacitation.

Cytogenetic studies were made on 328 spermatozoa from three individuals using either fresh semen samples capacitated in Biggers, Whitten and Whittingham (BWW) medium plus human serum albumin (BWW + HSA) or semen samples preserved at 4 degrees C in TEST-Yolk buffer. A total of 261 sperm karyotypes were obtained in a series of experiments in which half of each sample was capacitated in BWW + HSA and the other half in TEST-Yolk buffer at 4 degrees C for 2 days; 123 and 138 sperm karyotypes were obtained from the two capacitation methods respectively. Neither the frequency of sperm chromosomal abnormalities nor the sex ratio was significantly different after each capacitation methods. In one individual, however, the sex ratio (19X:32Y in the fresh sample and 49X:28Y in the preserved sample) did show a significant difference. In three experiments with semen samples from a single individual capacitated at 4 degrees C for 1, 2 or 3 days in TEST-Yolk buffer we obtained 33, 30 and 34 sperm karyotypes respectively. No significant differences in the sex ratio was exhibited between these experiments; the number of chromosome anomalies was too low to allow statistical analysis. Our results suggest that TEST-Yolk capacitation for 1, 2 or 3 days does not induce significant variations in the frequency and type of chromosomal abnormalities in human spermatozoa.

Animals↗
PubMed1991

XY-trivalent association and synaptic anomalies in a male carrier of a Robertsonian t(13;14) translocation.

Synaptonemal complexes were analysed in 91 pachytenes from a patient carrier of a Robertsonian translocation 45XY, t(13;14). Electron microscopic studies were carried out in 36 pachytenes. In some cases, sequential light microscopy/electron microscopic images were obtained (16/36). As the resolution of the light microscope does not allow an accurate characterization of anomalies, only EM images have been taken into account. Association of the trivalent and the sex vesicle was detected in 8 of 36 pachytenes (22.2%). Synaptic anomalies (25%), fragmentation of synaptonemal complexes (11.1%) or both (2.8%) were seen in 14 of 36 nuclei. According to previous studies, synaptic anomalies may produce a spermatogenic arrest. However, it has been suggested that synaptic anomalies may be the result of a process of cell degeneration, and not its cause. The non-random relationship between the sex vesicle and the translocation trivalent may result from the tendency of unpaired segments to associate with each other after homology search is relaxed and heterologous synaptic adjustment is allowed.

Adult↗
PubMed1991

Location of phosphorylated residues in human respiratory syncytial virus phosphoprotein.

The phosphoprotein (P protein) from human respiratory syncytial virus Long strain, labelled in vivo with [32P]orthophosphate, was purified from virions or virus-infected human epithelial (Hep-2) cells. The main phosphorylated amino acid found was serine. The determination of the N-terminal sequence of unphosphorylated and phosphorylated fragments of P protein obtained after chemical or enzymic treatments suggested that some or all of the six serines present at positions 116, 117, 119, 143, 156 and 161 are the major phosphorylated residues, although a modification in serine residues at positions 86, 94 and 99 can not be ruled out.

Amino Acid Sequence↗
PubMed1991

DNA restriction fragment length polymorphism differentiates crossed from independent infections in nosocomial Xanthomonas maltophilia bacteremia.

Restriction fragment length polymorphisms of total DNA and rDNA were used to study the relationship between 11 isolates of Xanthomonas maltophilia, obtained from seven patients with nosocomial bacteremia in four distinct wards of a single hospital, and the type strain of the species, ATCC 13637. Our results indicated that there were episodes of cross-infection among the patients of two wards, but there were also independent infectious episodes in the two other wards.

Child↗
PubMed1991

[Controversies over regional lymphadenectomy in carcinoma of the penis].

Epidermoid carcinoma of the penis, although rare, is a very aggressive tumor type. The presence or absence of inguinal metastasis is an essential prognostic factor. Treatment of these metastases is one of the current controversies in urological practice; i.e., when and to what extent lymphadenectomy should be performed. Of 24 patients with penile carcinoma, 10 had undergone regional lymphadenectomy over the past 8 years at our institution. Following treatment of the primary penile tumor, 6 patients had palpable inguinal nodes that persisted after treatment with antibiotic and antiinflammatory agents for 6 weeks. Of these, 3 had a positive node biopsy. They were submitted to regional lymphadenectomy which revealed node metastasis in 5 cases (2 pN3, 2 pN2 and 1 pN1). The patients with no palpable nodes were closely followed and were submitted to lymphadenectomy when these appeared (3 cases). The fatal outcome of 2 cases (both pN3) prompted us to perform lymphadenectomy prophylactically in the last case, a 40-year-old male with pT2G2 N0 penile cancer. This approach is advocated in patients under 65 with invasive penile carcinoma (pT greater than 1) or a high histological grade of malignancy (G2 and G3).

Adult↗
PubMed1991

Tetany induced on separate occasions by administration of potassium and magnesium in a patient with hungry-bone syndrome.

The case is described of a 68-year-old man whose therapy induced tetany during each of two consecutive hospital admissions. On each occasion the patient had marked hypocalcemia and hypomagnesemia, presumably as a result of the hungry-bone syndrome associated with diffuse prostatic osteoblastic metastases. During the February 1991 admission, marked hypokalemia was the principal initial concern. It seems likely that the tetany associated with the administration of KCl, without sufficient calcium, resulted from attenuation of the protection against hypocalcemia-enhanced neuromuscular excitability conferred by coexisting hypokalemia. The admission in March 1991 was prompted by the finding (without symptoms) of very low levels of both serum Mg and serum Ca. Tetany occurred during the infusion of MgSO4, without calcium. An acute decrement in plasma ionized Ca resulting from complexing of Ca with sulfate ions together with augmented urinary excretion of Ca were likely pathogenic factors.

Aged↗
PubMed1991

Giant multilocular prostatic cystadenoma: a distinctive lesion of the retroperitoneum in men. A report of two cases.

Two examples of large, multiloculated, cystic tumors that arose within the pelvis in men of 28 and 37 years of age are described. The tumors were composed of glands and cysts lined by prostatic-type epithelium lying in a hypocellular fibrous stroma. The prostatic nature of the lesions was confirmed by immunohistochemical staining of the epithelium for prostate-specific antigen and prostatic acid phosphatase. Two apparently similar lesions were found in the literature; one tumor was attached to the prostate by a pedicle, and the other arose in the retrovesical space. These tumors, for which we propose the designation "giant multilocular prostatic cystadenoma," appear to be benign, although they may recur if incompletely excised. They may pose considerable diagnostic difficulty if the prostatic nature of the epithelium is not appreciated, an error that is likely if a relationship to the prostate is not recognized. This lesion should be included in the differential diagnosis of retroperitoneal cystic tumors in men.

Adult↗
PubMed1990

Molecular cloning of the fMet-Leu-Phe receptor from neutrophils.

The bacterial chemotactic peptide fMet-Leu-Phe (fMLP) activates neutrophils upon binding to surface receptors. In a previous communication we reported the functional reconstitution of the fMLP receptor in Xenopus laevis oocytes (Coats, W. D., and Navarro, J. (1990) J. Biol. Chem. 265, 5964-5966). In this work we report the isolation of the cDNA encoding the fMLP receptor from neutrophils. A rabbit neutrophil cDNA library was screened with an oligonucleotide probe deduced from the nucleotide sequence of G-protein-coupled receptors, and a cDNA encoding the fMLP receptor was isolated. This cDNA was characterized according to the following criteria: 1) Analysis of the deduced amino acid sequence revealed that the clone belongs to a G-protein-coupled receptor. 2) Tissue distribution analysis of the mRNA indicated that the message is only found in neutrophils. 3) In vitro translation of the message revealed a protein corresponding in size to the deglycosylated fMLP receptor. 4) X. laevis oocytes injected with the fMLP receptor message exhibited fMLP-dependent calcium mobilization and specific binding to the fMLP analog 125I-labeled fNle-Leu-Phe-Nle-Tyr-Lys (where Nle is norleucine and fNle is formylnorleucine). The molecular cloning of the fMLP receptor should provide the framework to analyze the relationship between structure, function, and regulation of this receptor.

Amino Acid Sequence↗
PubMed1990

[Results of dietetics and nutritional assistance in cystic fibrosis].

The development of gastric acid-protected pancreatic extracts has radically transformed the diet of patients with cystic fibrosis, who are now provided with a high-caloric, hyperproteinic and normo- or hyperlipidic diet, with a correct supplementation in minerals, vitamins and oligo-elements. Nutrition has a major influence on the course of the disease, and the evaluation of the patients' needs has already shown that these are clearly increased in cystic fibrosis. In the severe and advanced forms of the disease, when refractory anorexia is added to chronic infection, more or less sophisticated techniques of nutritional assistance, such as oral supplementations and enteral or even parenteral feeding, are carried out. These techniques not only improve the anthropometric nutritional parameters, but if they have been prescribed soon enough they also interfere with the outcome of the disease.

Cystic Fibrosis↗
PubMed1990

Functional reconstitution of fMet-Leu-Phe receptor in Xenopus laevis oocytes.

fMet-Leu-Phe (fMLP) receptors were functionally reconstituted into Xenopus laevis oocytes by microinjection with RNA isolated from promyelocytic leukemia cells (HL-60) differentiated with 750 microM N6, O2-dibutyryl cyclic adenosine 3',5'-monophosphate. fMLP-induced Ca2+ mobilization was monitored by measurement of photon emission elicited by aequorin coinjected with RNA into albino X. laevis oocytes. Maximal expression of the fMLP receptor was achieved 48 h after microinjection of RNA. Dose-response experiments revealed a K0.5 of 9.5 nM fMLP which is in good agreement with the dissociation constants of the fMLP receptor complex in human neutrophils. Furthermore, the fMLP-induced Ca2+ mobilization in Xenopus oocytes was blocked by the fMLP receptor inhibitor t-butoxycarbonyl-Met-Leu-Phe. Size fractionation of the RNA and microinjection of the individual fractions indicated that messenger RNA for the fMLP receptor is between 1.5 and 2.0 kilobases. Reconstitution of the fMLP receptor into Xenopus oocytes can be employed to isolate the cDNA encoding the fMLP receptor as well as to study the regulation of the fMLP receptor in a functional system.

Animals↗
PubMed1990

Meiotic and sperm chromosome studies in a reciprocal translocation t(1;2)(q32;q36).

Meiotic and sperm chromosomes were studied in a man heterozygous for a reciprocal translocation t(1;2)(q32;q36). Forty-five meiotic metaphase I cells were obtained from semen samples: 86.6% were 22,XY,IV and 13.3% had synaptic anomalies that affected all or some of the bivalents. The quadrivalents observed had a ring configuration (92.3%) or a chain configuration (7.7%). A total of 105 sperm chromosome complements were analyzed: 41% resulted from an alternate segregation, and the percentage of unbalanced sperm was 59%; most of them (71%) resulted from an adjacent 1 segregation. The frequency of anomalies unrelated to the translocation (5.7% numerical and 14.1% structural anomalies) were within the normal range for control donors. There was a good correspondence between the percentage of cells with a ring IV (92.3%) and the proportion of 2:2 segregations (88.6%) and between the percentage of chain IV (7.7%) and the incidence of 3:1 segregations (11.4%).

Chromosomes, Human, Pair 1↗