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Biomedical subjects

F Cruz

Publications and source records attributed to F Cruz.

At least 55 records · Page 3Linked to original sources
PubMed1994

Activation of the c-fos proto-oncogene in the spinal cord following noxious stimulation of the urinary bladder.

Activation of the c-fos proto-oncogene following mechanical or chemical noxious stimulation of the urinary bladder was studied at T12-L2 and L5-S1, the spinal cord segments of projection of the hypogastric nerve (HGN) and pelvic nerve (PN) fibers, respectively. In intact adult rats, c-fos expression was found at T12-L2 only in lamina I. At L5-S1, Fos cells occurred in lamina I, the intermediolateral gray matter (ILG), and the dorsal commissure (DCM). These two areas contained the highest number of immunoreactive cells. Although more Fos cells were induced by mechanical than by chemical stimulation, the distribution of the reactive neurons was similar after both types of stimuli. In adult rats that had been treated neonatally with capsaicin, there was a marked fall in c-fos activation by mechanical or chemical noxious stimuli in all immunoreactive areas. The loss of Fos cells was more pronounced in ILG and DCM at L5-S1 (95%) than in lamina I at the two spinal domains (70%). The confinement of c-fos activation to lamina I at T12-L2, the spinal cord domain of the HGN, suggests that the input carried from the bladder by this nerve is preferentially used for pain perception. The same function is expected for noxious input reaching lamina I at L5-S1, the spinal cord territory of termination of the PN. However, the striking number of Fos cells in ILG and DCM supports the important role played by this nerve in the control of the micturition reflex.(ABSTRACT TRUNCATED AT 250 WORDS)

Afferent Pathways↗
PubMed1993

Periterminal synaptic organization of primary afferents in laminae I and IIo of the rat spinal cord, as shown after anterograde HRP labelling.

The fine structure and periterminal synaptology of the primary afferent terminations in laminae I and IIo are examined in the rat, following anterograde labelling with horseradish peroxidase applied to the right C5-dorsal root. Labelled varicosities observed along the terminal arbors in parasagittal thick sections were relocated in ultrathin sections by electron microscopy. The labelled terminal profiles generated by the three primary afferent plexuses which can be identified by light microscopy in laminae I-IIo had similar fine structural features, except that axo-axonal contacts, although rare, were more frequent in the medial network plexus. Primary boutons were packed with agranular spherical vesicles and some large granular vesicles, and were mostly presynaptic to profiles of dendritic trunks of marginal cells. Unlabelled axonal profiles, either light with some flattened vesicles, or dense with round vesicles, were also presynaptic at symmetrical or asymmetrical contacts, respectively, to those dendritic profiles. It is suggested that such knobs of intrinsic origin are responsible for postsynaptic modulation of the primary noxious input. Although the 20 microns wide lamina IIo belongs cytoarchitectonically to lamina II and can be distinguished from lamina I by a decreased amount of myelinated fibres and large dendritic profiles, the periterminal synaptology was here found to be the same as in lamina I.

Afferent Pathways↗
PubMed1993

[Percutaneous biliary endoprostheses. Clinical experience of 6 years].

The aim of this study was to assess the effectiveness and long term permeability of percutaneous biliary endoprostheses. Seventy three patients with biliary tract obstruction due to a primary malignant tumor (n = 60), lymph node metastases at the porta hepatis (n = 10) and benign stenosis of a biliary-enteric anastomosis (n = 3), were treated between 1985 and 1990. Plastic prostheses were installed in 63 patients and metallic in 10. The procedure had a 30% incidence of complications. Thirty three percent of the prostheses remained patent until patient's death. In 15 and 40% of patients, signs of prosthesis obstruction were observed three and six months after installation respectively, bearing in mind a mean survival of 24 weeks. In 90% of patients there was a clinical and laboratory improvement. Mortality was 30% at 30 days in the group of patients with malignant diseases. It is concluded that the installation of percutaneous biliary endoprostheses is a relatively safe and well tolerated procedure, with a low incidence of complications or mortality and that allows an effective biliary decompression.

Adult↗
PubMed1993

Pregnancy and cholelithiasis: pathogenesis and natural course of gallstones diagnosed in early puerperium.

Several recent reports have indicated an increased prevalence of gallstones in association with pregnancy. If these reports are true, the early puerperium should be a favorable time to detect the disease in its initial stages and follow its natural course. Accordingly, the gallbladder was examined by ultrasound in 980 women during the immediate postpartum period and in 150 nulliparous, age-matched healthy volunteers. Gallstones were detected in 12.2% of the puerperal women and in 1.3% of the control group. In 70 patients who had stones in a functioning gallbladder, 22 (31%) had had attacks of biliary colic. The history of pain was more common in patients with stones greater than 10 mm in diameter. Forty-one women with small stones (< 10 mm) were followed clinically and ultrasonographically for between 6 and 24 (mean = 8.7) mo. All remained pain-free, and in twelve subjects (29%) the stones disappeared. Gallbladder bile was examined in 11 normal volunteers (controls) immediately after delivery and in 19 women with small stones 39 +/- 6 days postpartum. Bile was saturated with cholesterol in the controls and was unsaturated in patients with gallstones. We conclude that in our population pregnancy is a very important pathogenetic factor favoring gallstone formation. Attacks of biliary colic appear early and frequently in young Chilean women with this disease. Unexplained disappearance of small stones frequently occurs: in some cases it is likely to be the result of spontaneous dissolution because bile becomes unsaturated within a few weeks of delivery.

Abdominal Pain↗
PubMed1992

Immunocytochemical staining of neuropeptides in terminal arborization of primary afferent fibers anterogradely labeled and identified at light and electron microscopic levels.

A method is described to combine, at the ultrastructural level, horseradish peroxidase (HRP) anterograde tracing of primary afferents and peptide immunocytochemistry, using the lateral plexus of primary afferent fibers in laminae I-IIo of the rat dorsal horn as a model system. Free HRP was crushed against the dorsal roots. After a 14-h survival, animals were perfused, and the spinal cord was sliced at 50 microns with a Vibratome in a parasagittal plane. From these thick sections, camera lucida drawings of HRP-labeled fibers were obtained. Following osmication and Epon flat embedding, thick sections were re-cut at 5 microns and the labeled arbors matched with those previously drawn from the 50-microns sections. Ultrathin sections were cut from the 5-microns semithin sections and directly stained on grids using a post-embedding immunogold labeling procedure. Single and/or double immunocytochemical staining was performed using a rat monoclonal antibody against substance P and a rabbit polyclonal antiserum against calcitonin gene-related peptide (CGRP). Immunocytochemical reactions were visualized using appropriate immunoglobulin G-gold conjugates and the double-labeled synaptic boutons were matched with the varicosities previously visualized at the light level in the thick and semi-thin sections. The major advantages of this method are: (i) correlative studies at light and electron microscope level are made possible; (ii) tissue ultrastructure and antigenicity are adequately preserved so that a reliable subcellular localization of antigens under study is obtained; (iii) the markers used for tracing and immunocytochemistry are clearly distinguishable, even when present in the same nerve profile; and (iv) anterograde tracing can easily be combined with multiple immunolabeling.

Animals↗
PubMed1992

[Correlation between ultrasound and pathology of the gallbladder].

Ultrasound is a sensible and specific method for the diagnosis, study of natural course and follow up of medical treatment of gallstones. Thus it is important to specify the concordance between echographic and pathological findings of the gallbladder. Ninety one patients were subjected to an ultrasound gallbladder examination immediately before elective surgery and the excised organ was pathologically examined right after the operation. The number and size of stones, the diameters and wall thickness of the gallbladder and the presence of polyps and septa were compared with both methods. The correlation was fair for the number or size of the stones considered separately; however the correct diagnosis of both parameters was obtained in only a third of the cases. Diameters of the gallbladder were underestimated by ultrasound; wall thickness measurement showed a very good correlation with both methods. No correlation was found for polyps or septa. Although ultrasound is excellent for the diagnosis of gallstones, its precision, is insufficient to determine the exact number and size of the stones.

Cholelithiasis↗
PubMed1992

[Computed tomography guided fine needle aspiration biopsies].

Computed tomography (CT) allows the performance of fine needle aspiration biopsies in situations in which ultrasound or conventional X rays do not correctly visualize the lesion or the needle tract. One hundred four patients with a clinical suspicion of neoplasia were subjected to CT guided percutaneous aspiration biopsies in a lapse of 6 years. The most frequently biopsied organs were the lung (39.5%), liver and gallbladder (20.2%) and pancreas (15.4%). Forty nine percent of procedures were performed in the thorax and 51% in the abdomen. Of 51 patients with suspicion of thoracic cancer, there was only one false negative and no false positive results, with an overall accuracy of 98%. For abdominal procedures, there were no false positive results, although there were 6 false negative results, specially for pancreatic or retroperitoneal lesions. Overall accuracy for abdominal procedures was 88%. It is concluded that CT guided fine needle biopsy is a safe and accurate method for the diagnosis of thoracic and abdominal lesions.

Abdominal Neoplasms↗
PubMed1991

Fine structure and synaptic architecture of HRP-labelled primary afferent terminations in lamina IIi of the rat dorsal horn.

The fine structure and synaptic architecture of the afferent terminations in dorsal horn lamina II are studied using a combined light and electron microscopic procedure after anterograde labelling with horseradish peroxidase. Vibratome parasagittal sections, stained with heavy metal intensified diaminobenzidine after tracer application to the dorsal roots, were flat-embedded in Epon. The five types of labelled terminal arbors occurring in lamina IIi (Cruz et al., '87: J. Comp. Neurol. 261:221-236) were drawn and relocated in 5-microns sections cut serially from the thick sections. Ultrathin sections were then cut from the 5-microns sections so that the terminal fibers and swellings observed in the light microscope could be traced in the electron microscope. The flame-shaped arbors arose from fine myelinated stem fibers. Terminal strands generated large oval central terminals of type II synaptic glomeruli (CII), which established frequent axoaxonal contacts. Similar terminals have been labelled in the cat after tracer injections into hair-follicle fibers (Réthelyi et al., '82: J. Comp. Neurol. 207:381-393). The other four plexuses arose from unmyelinated stem fibers. The swarms of ultrafine boutons consisted of extremely thin terminal fibers generating very small, round, or polygonal glomerular terminals containing tightly packed agranular synaptic vesicles of variable size and one mitochondrion at best. The terminal strands of the bouquet plexus bore long and scalloped central varicosities of type I synaptic glomeruli (CI) with pleomorphic agranular vesicles and a relative abundance of dendroaxonal contacts. These features, together with the location in dorsal lamina IIi, suggest their belonging to the fluoride resistant acid phosphatase (FRAP)-reactive population. The boutons of the undulating fibers and those of the lateral plexus were, like those of the bouquets, scalloped and elongated rostrocaudally (CI), but contained a few large granular vesicles. The occurrence of the swarm, undulating, and lateral plexuses in ventral lamina IIi, which seems to lack FRAP or peptidergic terminals, suggests an origin from other, still unidentified neurochemical populations of fine primary afferents.

Animals↗
PubMed1990

An artificial neural network to localize atrioventricular accessory pathways in patients suffering from the Wolff-Parkinson-White syndrome.

UNLABELLED: The electrocardiographic localization of atrioventricular accessory pathways has been extensively described in the literature by a number of well-known electrophysiologists and surgeons. These descriptions, often represented as decision trees, are useful, but do not apply in all cases. To formalize the process of determining the proper localization, this expert human knowledge could be represented in an expert system. But since reasoning is partly based on the use of heuristic knowledge, and are often not represented in the written description of the human expert, the results will be suboptimal. On the other hand, by using a self-learning neural network approach, the causal relations between input (polarity of the delta waves) and output (the correct localization) do not have to be defined by the expert. It is derived by the neural network, by analyzing a learning set of cases consisting of the ECG plus the corresponding correct localization. In our set of 60 cases, 2 hours of training were required to learn how to localize all cases correctly. From a control set of 25 cases, 23 were interpreted by the system satisfactorily. CONCLUSION: the neural network approach can be useful in situations where causal relations between the electrocardiogram and underlying mechanism are partly undefined.

Artificial Intelligence↗
PubMed1990

Extrathoracic staging of bronchogenic carcinoma.

In assessing the value of systematic evaluation of extrathoracic extension for potentially resectable, non-small-cell bronchogenic carcinoma, a prospective study was conducted in 146 patients. The study protocol included computed tomographic (CT) scan of the brain and upper abdomen, abdominal ultrasonography, and whole-body bone scanning. The findings were matched with the clinical presentation, histologic features, and TN staging, having found out that non-small cell bronchogenic carcinoma does not follow a set pattern to metastasize. The rate of metastasis for adenocarcinoma is not only significantly larger (p less than 0.05) but it does not correlate with the TN staging, in contrast to what happens with the squamous cell carcinoma (p less than 0.01). None of the squamous cell carcinomas in intrathoracic stage I was found to metastasize. Twenty-one percent (4/19) of brain metastases were asymptomatic (three adenocarcinomas and one squamous cell carcinoma with multiorgan metastasis). Bone scanning detected metastasis in 3.4 percent (4/116) of the asymptomatic patients, and three of the four patients with asymptomatic metastasis had nonskeletal foci. In 61 percent (11/18) of patients with hepatic metastasis, we did not find organ-specific indicators to suspect it. The series showed a 7.5 percent incidence of adrenal metastasis. Our findings suggest the convenience of performing an upper abdominal CT scan and/or ultrasonography in all patients, except for those with asymptomatic stage I squamous cell carcinoma; we also suggest brain CT scanning for all patients with adenocarcinomas and large-cell carcinomas as well as for those with squamous cell carcinoma with neurologic symptoms, and whole-body bone scanning only in those patients with clinical and laboratory indication of possible bone involvement by metastatic disease.

Abdominal Neoplasms↗
PubMed1989

Influence of legume intake on biliary lipids and cholesterol saturation in young Chilean men. Identification of a dietary risk factor for cholesterol gallstone formation in a highly prevalent area.

Chileans and North American Indians have one of the highest prevalence rates of cholesterol gallstones in the world. The most common theory to explain this has been the operation of some as yet undefined genetic risk factor in these populations. Searching for some common environmental factor for gallstones in Chileans and North American Indians, we found that beans and other legumes are common foods consumed by both populations. In this study we tested the hypothesis that legume intake may favor the production of biliary cholesterol supersaturation. We studied 20 young men subjected to a diet containing 120 g/day of legumes and a control diet without legumes for a period of 1 mo each. Both diets supplied identical quantities of energy, carbohydrates, protein, total fat, fiber, and cholesterol. Low-density lipoprotein cholesterol concentration decreased by 16% (p less than 0.001) after the legume diet. Biliary cholesterol saturation increased in 19 of the 20 subjects; the mean of the group markedly increased from 110% to 169% (p less than 0.001) after the legume diet. These results are consistent with the hypothesis that legume intake is a potential risk factor for cholesterol gallstone disease.

Adult↗
PubMed1988

The actions of phenol and pentachlorophenol (PCP) on axonal conduction, ganglionic synaptic transmission, and the effect of pH changes.

1. A comparison of phenol, pentachlorophenol (PCP) and procaine effects on axonal conduction were studied in vitro in the sciatic nerves of toad. PCP and procaine were respectively 6.3 and 3.15 times more potent than phenol in blocking axonal conduction. 2. Effects of PCP on synaptic transmission were studied in vitro in the eighth sympathetic ganglion of toad. 3. Axonal conduction block and synaptic transmission block by phenol was reversible, but not that by PCP. 4. When the PCP ionization was increased, a lesser per cent reached the site of action, reducing its capacity to block the axonal conduction and ganglionic transmission. 5. PCP plus, 3,4-Diaminopyridine (3,4-DAP) decreased synaptic transmission block from post-ganglionic compound action potential (CAP) responses to supramaximal preganglionic stimulation.

4-Aminopyridine↗
PubMed1987

Several morphological types of terminal arborizations of primary afferents in laminae I-II of the rat spinal cord, as shown after HRP labeling and Golgi impregnation.

The morphology of the terminal arborizations in laminae I-II of primary afferent fibers was studied in sections stained by the heavy metal (nickel and cobalt) intensification of diaminobenzidine (DAB) after crushing one dorsal root with horseradish peroxidase (HRP) crystals, and with the mixed Golgi method which duplicated the staining provided by the first method. Besides the flame-shaped arbors located in deep lamina IIi as an extension of the arbors of lamina III, which were derived from 1.7-micron thick stem fibers (probably A alpha beta fibers), six types of terminal arbors, all rostrocaudally oriented, arising from fine stem fibers and having preferential locations, were disclosed. The lateral third of laminae I-II contained a longitudinal plexus of parallel 0.8-micron thick stem fibers (C fibers) with longitudinal side branches generating many boutons en passant. Laminae I and IIo, in their middle third, contained dichotomizing longitudinal fibers with elongated boutons, arising from 1-micron thick stem fibers (C or A delta), and, in the medial third, a dense plexus with terminal networks carrying large boutons, which arose from 1.3-micron thick stem fibers (A delta). Fibers ending in terminal bouquets and issuing from 1-micron thick stem fibers (C or A delta) occupied the dorsal part of middle and medial lamina IIi, while the intermediate part contained clusters (swarms) of ultrafine boutons arising from extremely fine fibers. The whole medial lamina IIi also contained fine undulating fibers arising from 0.3 micron-thick stem fibers (C fibers) with large boutons near their ends. The functional meaning of this multiplicity of morphological types and locations is still unclear. It may be clarified when single unit analysis of HRP-injected fine fibers is made possible, or immunocytochemical stainings disclose the neurotransmitters utilized by each fiber type.

3,3'-Diaminobenzidine↗
PubMed1986

Transmission of hepatitis B with resultant restriction of surgical practice.

Five patients developed acute hepatitis B (HB) within four months after major operations by the same obstetric-gynecologic surgeon. Investigation documented that the surgeon was HB surface antigen and HB e antigen positive; all five patients had an HB subtype matching that of the surgeon and no other identifiable risk factors for HB viral infection. A seroprevalence study comparing exposed surgical and obstetric patients with a control group showed no significant additional subclinical HB transmission. The surgeon resumed his surgical practice but was required to obtain written informed consent from patients, to double-glove, and to employ appropriate surgical techniques to avoid self-injury. Seven months later, acute HB occurred in a patient two months after a cesarean section, resulting in exclusion of the surgeon from major operations. This is the fifth outbreak of nosocomial HB linked to an obstetric-gynecologic surgeon, and it reinforces the need for health care workers to receive preexposure prophylaxis with HB vaccine to prevent such occurrences.

Carrier State↗
PubMed1986

Giant venous aneurysm associated with hypogastric arteriovenous malformation.

Venous aneurysms are extremely rare. They may be congenital or acquired in origin and occasionally related to arteriovenous communications. A 58-year-old man complained of dull left lower quadrant pain and constipation. On physical examination a soft deep mass was palpated. Ultrasonogram and CT scan revealed a cystic formation in the pelvic cavity. Angiograms disclosed an arteriovenous malformation (AVM) at the pelvic floor draining into a large cavity. The patient was successfully managed by intraoperative selective embolization of the AVM and partial resection of a 10.6 x 8 x 6.7 cm venous aneurysm. The histopathologic studies of the wall confirmed a venous structure. Venous dilatation has been reported in high flow vein grafts, blood access V fistulas and rarely, proximal to traumatic AV fistulas of the lower extremities. The etiology of the present case is probably congenital, being to the best of our knowledge, the first case affecting the hypogastric territory, reported in the English literature.

Aneurysm↗