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Biomedical subjects

M Campos

Publications and source records attributed to M Campos.

At least 73 records · Page 4Linked to original sources
PubMed1996

[Ureteral obstruction caused by periureteral venous dilatation secondary to infrarenal caval obstruction].

Presentation of a case report of a female patient with single right kidney and background of left nephrectomy 21 years earlier due to hypertension who presented to the clinic after an episode of oliguria with lower limbs oedema and renal failure. Renal ultrasound evidenced moderate hydronephrosis, and backward pyelography showed medialization and lumbar ureter compression. CAT examination confirmed the ureteropyelocalycectasis as well as the reduction of the infrarenal lower cava vein to a fibrous cord with internal calcification. Axillary cavography and venography through both femorals demonstrated absence of the infrarenal cava vein segment and existence of a large replacement venous network. During surgery it became evident that the latter was displacing a retrovenous right lumbar ureter medially. Ureterolysis and ureter section with transposition, and termino-terminal anastomosis were performed. The morphological and functional results were excellent with recovery of the renal function (normal serum creatinine) which is still maintained after 7 years follow-up. As a consequence of this case, a review was made of different cava vein anomalies with repercussion in the urine excretory tract.

Aged↗
PubMed1995

Inhibition of murine peritoneal macrophage functions by sulfated cholecystokinin octapeptide.

The effect in vitro of the sulfated octapeptide form of cholecystokinin, CCK-8, at concentrations from 10(-12) M to 10(-6) M on several functions of resting peritoneal macrophages from BALB/c mice: adherence to substrate, mobility (spontaneous and directed by chemical gradient or chemotaxis), ingestion of inert particles (latex beads) or cells (Candida albicans), and production of superoxide anion measured by nitroblue tetrazolium reduction was studied. CCK-8, at concentrations from 10(-10) M to 10(-8) M, inhibited significantly all functions studied with the exception of adherence to substrate, which was increased. A dose-response relationship was observed, with a maximum inhibition of macrophage functions found at 10(-8) M. This neuropeptide induced in murine macrophages a significant, but transient, increase of cAMP levels at 60 sec. On the contrary, CCK-8 produced a slight but significant decrease of protein kinase C (PKC) activity at 5 min of incubation. These results suggest that CCK-8 is a negative modulator of several macrophage functions, and that the inhibition of these activities is carried out through an increase of intracellular cAMP levels and a decrease in PKC activity.

Animals↗
PubMed1995

Fast imaging MR assessment of ureterohydronephrosis during pregnancy.

PURPOSE: to assess the value of the fast imaging sequence called RARE-MR-Urography (RMU) for the diagnosis of pathologic ureterohydronephrosis during pregnancy. MATERIALS AND METHODS: 15 pregnant women with an acute flank pain were examined with RMU. Results were compared with those of ultrasonography (US), X-rays, and the evolution of symptoms. RESULTS: the accuracy of RMU in the detection of urinary tract dilatation and the localization of the level of obstruction was excellent (100%). The determination of the type of obstruction, intrinsic vs. extrinsic, was always exact. RMU alone cannot specify the exact nature of the intrinsic obstruction. Ultrasonography gave less sensitive information in terms of level (60%) and type of obstruction (53%). CONCLUSION: RMU is able to differentiate a physiological from a pathologic ureterohydronephrosis during pregnancy. It could be considered as a procedure of choice for special cases when US failed to establish this differential diagnosis.

Adult↗
PubMed1995

Clinical characteristics and risk factors for Vibrio cholerae infection in children.

Surveillance was conducted during February and March 1991 in the pediatric emergency department of Cayetano Heredia Hospital, Lima, Peru, to contrast the characteristics of children with epidemic cholera with those of children with noncholera-associated diarrhea. Among 626 patients 14 years of age or younger, Vibrio cholerae O1 was isolated from stool specimens of 310 patients (49%), more commonly from children older than 24 months of age (66%; p < 0.0001) than from younger children. Cholera was clinically characterized by a more sudden onset; watery diarrhea; and associated abdominal pain, muscle cramps, and vomiting, which led to more severe dehydration and hospitalization more often than in noncholera cases. Only one patient with cholera died, for a case-fatality rate of 3.2 deaths per 1000 persons. Nonpotable water and uncooked foods were identified as probable vehicles for V. cholerae. The frequency of diarrhea among relatives of patients with cholera suggested intrafamily transmission. This study of epidemic cholera describes the clinical features and the risk factors for acquisition of the infection, and points out the low case-fatality rate with prompt and appropriate treatment.

Abdominal Pain↗
PubMed1995

Lymphocyte proliferative responses to recombinant bovine herpes virus type 1 (BHV-1) glycoprotein gD (gIV) in immune cattle: identification of a T cell epitope.

The lymphocyte proliferative response to BHV-1 in immune cattle was compared to recombinant wild-type gD and truncated gD produced from recombinant vaccinia viruses. The response exhibited by recombinant proteins was comparable to the response induced by BHV-1 suggesting that gD is the major target structure for stimulation of bovine lymphocytes. Analysis of the proliferative response using vaccinia virus vectors expressing various modified forms of gD identified a region between residues 165 and 216 recognized by T-lymphocytes of immune cattle. Further analysis by overlapping peptides in this region localized the T cell epitope to residues 161-172. Antibody-blocking studies demonstrated that lymphocytes responding to this epitope are CD4+. In addition, lymphocytes stimulated with gD or peptide 77 (residues 161-172) also produced IFN-gamma and IL-2.

Animals↗
PubMed1995

Effects of long-term nitric oxide synthesis inhibition on plasma volume expansion and fetal growth in the pregnant rat.

We conducted the present study to investigate whether the vasodilator nitric oxide plays a role in plasma volume homeostasis during pregnancy. Pregnant Sprague-Dawley rats were randomly assigned to a control group (n = 18) or to groups receiving 0.69 mmol/L (n = 11) or 1.7 mmol/L (n = 14) N omega-nitro-L-arginine, a competitive inhibitor of nitric oxide synthetase, from gestational days 7 through 21. On day 20 systolic pressure was measured. On day 21 blood samples were taken for plasma volume, hematocrit, and hormonal measurements. Fetal and placental weights also were determined. Systolic pressure was significantly higher in experimental rats (101 +/- 6 and 115 +/- 6 mm Hg in the 0.69 and 1.7 mmol/L groups, respectively) than in controls (79.7 +/- 7.5 mm Hg), and plasma volume was lower (18.4 +/- 1.1 and 17.1 +/- 0.5 mL) than in controls (21.5 +/- 0.8 mL). Both experimental groups had increased hematocrit levels. Plasma renin activity was significantly lower in the experimental groups (11.5 +/- 3 and 7.2 +/- 1.5 ng angiotensin I/mL per hour) than in controls (21.9 +/- 2.7 ng angiotensin I/mL per hour); however, no changes were observed in aldosterone levels. Experimental groups had lower fetal weight (4.6 +/- 0.1 and 5.1 +/- 0.1 g) than controls (5.5 +/- 0.1 g). In addition, fetal hindlimb hypoplasia was observed in the experimental groups. In conclusion, the present data indicate that long-term N omega-nitro-L-arginine administration to pregnant rats leads to increased blood pressure, reduced plasma volume expansion, lower plasma renin activity, and fetal growth retardation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
PubMed1995

Local production of tumor necrosis factor-alpha in corynebacterial pulmonary lesions in sheep.

Corynebacterium pseudotuberculosis infection is a common cause of pyogranulomas in ovine lungs and often occurs as a dual infection with lentiviruses. This coinfection usually leads to the development of chronic pneumonia and cachexia that is similar to the clinical syndrome seen in human beings with AIDS-related pneumonias. Recent in vitro studies indicate that monokines such as tumor necrosis factor-alpha (TNF alpha) are induced by C. pseudotuberculosis, suggesting that TNF alpha is involved in the pathogenesis of corynebacterial lesions in vivo. To substantiate in vitro observations concerning bacterial induction of TNF alpha in ovine pulmonary macrophages, immunohistochemical labeling techniques were used in combination with in situ hybridization to identify TNF-producing cells in corynebacterial lesion sites in vivo. TNF alpha message and translation product were found in macrophages comprising pyogranulomas that were induced by naturally acquired and experimental pulmonary C. pseudotuberculosis infections.

Animals↗
PubMed1995

N-terminal amino-acid sequence of beta-lactamase from Shigella flexneri UCSF-129.

A beta-lactamase (EC 3.5.2.6 penicillinase, penicillin amino beta-lactam-hydrolase) was purified from Shigella flexneri USCF-129 by an efficient two-stage procedure involving chromatography in Sephadex G-75 and HPLC on a C18-reverse phase column. The homogeneity of the purified enzyme was confirmed by capillary zone electrophoresis (CZE), HPLC electrospray mass spectrometry (LC-ESMS) and amino acid sequence analyses. The highly purified enzyme was a monomeric protein with a molecular mass of 28.903 +/- 2 Da, as determined by LC-ESMS. The amino acid sequence of the first 49 N-terminal residues of this beta-lactamase revealed 100% similarity with the mature forms of the plasmid coded Escherichia coli enzymes (plasmid pBR 322 and R6K) a TEM-type beta-lactamase.

Amino Acid Sequence↗
PubMed1995

A chlamydial major outer membrane protein extract as a trachoma vaccine candidate.

PURPOSE: As shown in infected humans and in animal models of chlamydial infection, the major outer membrane protein (MOMP) of Chlamydia trachomatis is immunogenically potent. The purpose of this investigation was to test in the cynomolgus monkey model of trachoma a new extract of MOMP as a candidate vaccine against ocular chlamydial infection. METHOD: The nonionic detergent octyl-beta-D glucopyranoside (OGP) was used to extract MOMP from purified C. trachomatis (serovar C) elementary bodies. Protective immunization with OGP-MOMP by mucosal and systemic routes was compared in the cynomolgus monkey model of trachoma. All control and immunized monkeys were challenged by topical application of infectious C. trachomatis to the conjunctivae 35 days after the initiation of immunization. RESULTS: Immunization with OGP-extracted MOMP successfully induced chlamydia-specific local and systemic immunity to MOMP and to whole organism before challenge and early clearance of infection by systemically immunized monkeys. Although ocular disease was not significantly reduced in either immunized group compared to control animals, the lowest clinical and microbiologic disease scores developed in two animals in the mucosal group with the highest immunoglobulin A tear antibody titers at day 0 to 14, whereas higher tear and serum immunoglobulin G correlated with reduced disease in the systemically immunized group. CONCLUSIONS: These data demonstrate that despite evidence of vigorous MOMP-specific and other chlamydia-specific serologic and cell-mediated immunity, as well as anamnestic serologic responses to chlamydia, vaccination with OGP-MOMP was only partially protective against chlamydial ocular disease. The partial protection correlated best with tear immunoglobulin A responses after mucosal immunization and with local and systemic immunoglobulin G responses after peripheral immunization, suggesting that alternative chlamydial antigens may have to be considered in future vaccine development to induce more effective protective immunity and that evaluation of efficacy must be appropriate to route of immunization.

Administration, Oral↗
PubMed1994

Na(+)-ATPase activity of Na(+),K(+)-ATPase. Reactivity of the E2 form during Na(+)-ATPase turnover.

Based on work of Post et al. (Post, R. L. Toda, G., and Rogers, F.N. (1975) J. Biol, Chem. 250, 691-701), we studied the E2 form reactivity of Na(+),K(+)-ATPase (EC 3.6.1.37) during Na(+)-ATPase turnover by following ATP hydrolysis with and without P(i) and enzyme phosphorylation from P(i) at 20 degrees C. For theoretical calculations we employed the Albers-Post scheme assuming that, even with no K+, E2 exhibits the ATP regulatory site. Using available rate constants the model predicts: (i) without P(i), Na(+)-ATPase displays a single high affinity ATP site but becomes double Michaelian (with high and low ATP affinity) when P(i) is present. (ii) Phosphorylation from P(i) can be detected during Na(+)-ATPase (t 1/2 about 400 ms); the KmP(i) is substantially higher that the KdP(i). (iii) P(i) incorporation is reduced by ATP acting with low affinity; this does not require an increase in the E2-E1 transition rate. (iv) The KmATP of the regulatory site is augmented when [P(i)] increases. The experimental observations, using partially purified pig kidney enzyme, agreed with the predictions. In addition they showed that: (i) extracellular Na+ can prevent P(i) incorporation; this effect is additive with that of ATP but with independent Ki values. (ii) Mg2+ stimulates P(i) incorporation with low affinity (Km of 1.5 mM). (iii) beta, gamma-Methyleneadenosine 5'-triphosphate and palmitoyl-CoA antagonize P(i) inhibition of Na(+)-ATPase. These results agree with a model where the Na(+),K(+)-ATPase and Na(+)-ATPase cycles share most of their intermediate steps and enzyme conformations.

Adenosine Triphosphatases↗
PubMed1994

Keratocyte loss after corneal deepithelialization in primates and rabbits.

PURPOSE: To evaluate the response of stromal keratocytes to central corneal deepithelialization. METHODS: Rabbits and monkeys underwent unilateral mechanical deepithelialization with a blunt instrument and were killed at intervals ranging from 15 minutes to 24 hours after surgery. Two rabbits underwent unilateral deepithelialization under a fluid bath containing corneal preservation medium. Two rabbits were treated unilaterally with corneal preservation medium topically applied every 15 minutes for 16 hours after epithelial removal. Four rabbits underwent linear keratotomy immediately after deepithelialization of the cornea or on normal unoperated corneas and were killed 1 day (two animals) and 14 days (two animals) after surgery. RESULTS: Deepithelialization resulted in severe ultrastructural changes in keratocytes within 30 minutes after surgery. After 24 hours, the number of keratocytes in the anterior stroma underneath the deepithelialized area had decreased significantly in rabbits (P = .0001) and in monkeys (P = .0007) compared with controls. The wound healing was altered and delayed when the epithelium was not present after keratotomy. The use of storage media during and after deepithelialization minimized the early keratocyte changes and appeared to stimulate reepithelialization. CONCLUSIONS: Removal of corneal epithelium causes loss of superficial stromal keratocytes in rabbits and monkeys. Keratocyte death may results from osmotic changes that alter the corneal wound healing response.

Animals↗
PubMed1994

Proteolytic processing of von Willebrand factor subunit: heterogeneity in type-IIA von Willebrand disease.

Type IIA von Willebrand disease (vWD) is a heterogeneous disorder for which two different pathogenetic mechanisms have been proposed: increased proteolytic susceptibility of von Willebrand factor (vWF), and/or interference of its post-translational processing. Subunit analysis of vWF in type-IIA vWD has revealed an increased relative proportion of the 176- and 140-kDa subunit-derived fragments, suggesting an augmented fragmentation of vWF, even in the resting state. We analyzed the subunit pattern of vWF in plasma from five previously described patients with type-IIA vWD. All of them showed the above-mentioned pattern. In addition, the presence of a new band with an apparent molecular mass of 200 kDa, not described in normal individuals or in patients with vWD, was repeatedly observed in one of these patients. This patient also exhibited an abnormal vWF multimeric structure in platelets and in plasma, before and after desmopressin administration, when the blood was collected either in the presence or in the absence of proteinase inhibitors. We believe that an abnormal primary structure of vWF could be responsible for this abnormal proteolytic fragmentation pattern, as well as for the abnormal multimerization of vWF. Moreover, an abnormal susceptibility to proteolysis appears to be present, as suggested by the increase in the relative proportion of the 176-kDa fragment observed in the same patient. Future sequencing studies and genetic analysis may clarify whether there are one or two different defects related to the vWF of that patient. Our results indicate that the subunit analysis of vWF may reveal additional defects present in type-IIA vWD that may help our understanding of the pathogenesis of such disease.

Blood Platelets↗
PubMed1994

A slow release formulation for recombinant bovine interferon alpha I-1.

Recombinant bovine interferon-alpha I1 (rBoIFN-alpha) has known antiviral and immunomodulatory effects which have been exploited to reduce clinical disease in a number of clinical situations including bovine respiratory diseases. A slow release rBoIFN-alpha formulation may be of value to reduce bovine respiratory disease under field conditions by extending the period of protection, and hence improving the prophylactic benefits of rBoIFN-alpha. In this report, we describe a formulation of rBoIFN-alpha in sesame oil containing calcium stearate which can successfully sustain the release of rBoIFN-alpha over an 8-day period. Recombinant bovine IFN-alpha could be measured in serum for 8 days following treatment with an initial burst of release 6 h after injection. After a single subcutaneous depot injection of 50 mg and 100 mg of rBoIFN-alpha, initial serum levels reached 12-15 ng/ml and 25 ng/ml respectively. Correlating with this burst of release, there was a decrease in the number of circulating CD4-CD8- gamma delta+ T lymphocytes, and a slight neutropenia. No alterations in other cell phenotypes tested (CD4, CD8, CD2, CD6, B cells, monocytes or MHC class II) were observed, nor were there changes in lymphokine activated killer (LAK), natural killer (NK) cell activity, or oxygen radical formation (assessed by reduction of nitroblue tetrazolium). However, despite the rapid and short-lived burst of rBoIFN-alpha, levels of 2-5 oligoadenylate (2-5 A) synthetase remained elevated for 8 days. The sustained increase of 2-5 A synthetase was not due to the high initial dose released during the burst 6-12 h after injection, since injection of a bioavailable equivalent dose of interferon induced a significant rise in 2-5 A synthetase activity for 4 days only. As 2-5 A synthetase is known to be a correlate of antiviral activity, we propose that this formulation of rBoIFN-alpha may be one approach to increase the window of protection, leading to more effective prevention of bovine respiratory disease.

2',5'-Oligoadenylate Synthetase↗
PubMed1994

Keratocyte loss after different methods of de-epithelialization.

PURPOSE: To evaluate the response of corneal stromal cells to different types of superficial injury. METHODS: Twenty-two rabbits were randomized into five groups of four (with 2 untreated controls), and their corneas de-epithelialized (1) with a blunt instrument alone; (2) with an instrument and application of 100% ethanol, 0.5% proparacaine, or 4% cocaine; or (3) with the excimer laser. Twenty-four hours after surgery, the eyes were enucleated, and histologic changes were quantitated. RESULTS: All the methods of de-epithelialization used resulted in a decrease in the number of keratocytes relative to the control numbers (P = 0.0001). There is a significantly greater decrease in keratocyte counts with 0.5% proparacaine and 100% ethanol when compared with eyes injured by mechanical means, with 4% cocaine, or with the excimer laser (P = 0.009). All treatment groups showed more polymorphonuclear leukocytes than did controls (P < 0.0001). Mechanical de-epithelialization alone or in conjunction with proparacaine produced the least inflammatory response, but de-epithelialization with the laser was associated with a greater inflammatory response (P < 0.0001). CONCLUSIONS: All methods of de-epithelialization produced a significant decrease in rabbit cornea stromal keratocytes 24 hours after injury, associated with acute inflammation. Thus, it may be appropriate to avoid using chemicals, or if chemicals are used, to at least avoid using 100% ethanol. The applicability of these findings to humans has not yet been established.

Animals↗
PubMed1994

[The role of MRT in detecting the cause of therapy-refractory partial complex epilepsy].

MRT is of considerable significance in the investigation of epilepsy because of its ability to render soft tissue contrast for the demonstration of structural lesions. The present retrospective study consists of an analysis of MRT findings in operatively confirmed, circumscribed temporal tumours and in hippocampal sclerosis. The examinations were performed under standard conditions using T1- and T2-weighted spin-echo sequences of the head and coronal T2-weighted gradient-echo sequences of the brain stem. The diagnosis of tumours was extremely accurate (22/23) and specific (18/23) whereas hippocampal sclerosis could not be satisfactorily demonstrated (5/18). The use of intravenous contrast medium did not provide any advantages.

Adolescent↗