Parámetros para el monitoreo de la biota fúngica interior en un área subtropical

<p class="Default">En la práctica médica tienen cada vez más importancia las enfermedades causadas por hongos oportunistas adquiridas en ambientes hospitalarios. La mayor gravedad se presenta en lugares de alto riesgo, como guarderías, residencias de ancianos, quirófanos y Unidades de Terapia Intensiva (UTI)(1) . En los ambientes internos la proliferación de los contaminantes biológicos (principalmente hongos) se da en las zonas húmedas como floreros, humedad de las paredes, humidificadores, macetas con plantas y en las fibras capaces de retenerlos, a saber, filtros de aire, alfombras, cortinas de tela, pinturas porosas, etc. Estos contaminantes son transportados por visitantes, personal hospitalario, alimentos contaminados, sondas urinarias, equipos de terapia intravenosa e instrumentos mal esterilizados (2,3,4) . Entre los agentes más destacados se encuentran los mohos, Aspergillus, Penicillium, Fusarium, Alternaría, Cladosporiutn, Acremonium, Stachybotrys, Curvularia y Photna y las levaduras Candida, Cryptococcus, Rhodotorula y Geotrichum(1,5) . Por lo tanto, la vigilancia epidemiológica en los hospitales es necesaria para evitar infecciones fúngicas. Para ello, es imprescindible conocer la calidad del aire confinado, realizando un recuento selectivo de levaduras y de mohos, como el más elemental mecanismo de prevención de enfermedades</p>

[Clinical and epidemiological characteristics of patients with paracoccidioidomycosis diagnosed in a hospital of Resistencia, Chaco]

In order to describe the clinical and epidemiological characteristics of paracoccidioidomycosis, a descriptive study of all the cases diagnosed by the Clinical Microbiology Service at Dr. Julio C. Perrando hospital in the city of Resistencia (Chaco Province, Argentina) was conducted. Between 2011 and 2014, 46 cases were detected. In the period 2013-2014, an almost 4-fold increase in the incidence rate was detected. The chronic form of the disease was predominant with an average age of 53 years. Serological tests in 39 out of 46 patients were performed. In 15 of 39 patients, serological tests were the only diagnostic tool while in 4 patients with a microbiological diagnosis serological tests were non-reactive. In patients from endemic areas with non-specific infectious syndrome it is important to include paracoccidioidomycosis in the differential diagnosis and to apply all available diagnostic tools to reach a timely diagnosis and to reduce the long-term sequelae and their socio-economic impact.

Co-occurrence and seasonal and environmental distributions of the sandflies Lutzomyia longipalpis and Nyssomyia whitmani in the city of Puerto Iguazú, northeastern Argentina

The aim of this work was to study the distribution of Phlebotominae (Diptera: Psycodidade) abundance in time and space in an area in northeastern Argentina with vector transmission of visceral and tegumentary leishmaniasis. For this, 51 households were selected using a 'worst scenario' criterion where one light trap was set during two consecutive nights in peridomiciles in the transitions between the four seasons, and the environment was surveyed simultaneously. The relationships of phlebotomine assemblage structure and the most abundant species with seasonality and environmental variables were evaluated using a canonical correspondence analysis and generalized linear mixed models, respectively. A total of 5110 individuals were captured. Lutzomyia longipalpis (Lutz & Neiva, 1912) and Nyssomyia whitmani (Antunes & Coutinho, 1939) were the most abundant species captured in all samplings (98.3% of the total capture). The period of highest abundance of Lu. longipalpis was early autumn, and it was distributed in the most urbanized areas. Nyssomyia whitmani occupied mainly the less urbanized areas, showing peaks of abundance in early spring and summer. Other species were captured in low numbers and showed seasonal-spatial variations similar to those of Ny. whitmani. We confirmed Leishmania spp. vector persistence throughout the year in spatial patches of high abundance even during the less favorable season.

Azole-Resistance in Aspergillus terreus and Related Species: An Emerging Problem or a Rare Phenomenon?

Objectives: Invasive mold infections associated with Aspergillus species are a significant cause of mortality in immunocompromised patients. The most frequently occurring aetiological pathogens are members of the Aspergillus section Fumigati followed by members of the section Terrei. The frequency of Aspergillus terreus and related (cryptic) species in clinical specimens, as well as the percentage of azole-resistant strains remains to be studied.

Methods: A global set (n = 498) of A. terreus and phenotypically related isolates was molecularly identified (beta-tubulin), tested for antifungal susceptibility against posaconazole, voriconazole, and itraconazole, and resistant phenotypes were correlated with point mutations in the cyp51A gene.

Results: The majority of isolates was identified as A. terreus (86.8%), followed by A. citrinoterreus (8.4%), A. hortai (2.6%), A. alabamensis (1.6%), A. neoafricanus (0.2%), and A. floccosus (0.2%). One isolate failed to match a known Aspergillus sp., but was found most closely related to A. alabamensis. According to EUCAST clinical breakpoints azole resistance was detected in 5.4% of all tested isolates, 6.2% of A. terreus sensu stricto (s.s.) were posaconazole-resistant. Posaconazole resistance differed geographically and ranged from 0% in the Czech Republic, Greece, and Turkey to 13.7% in Germany. In contrast, azole resistance among cryptic species was rare 2 out of 66 isolates and was observed only in one A. citrinoterreus and one A. alabamensis isolate. The most affected amino acid position of the Cyp51A gene correlating with the posaconazole resistant phenotype was M217, which was found in the variation M217T and M217V.

Conclusions:Aspergillus terreus was most prevalent, followed by A. citrinoterreus. Posaconazole was the most potent drug against A. terreus, but 5.4% of A. terreus sensu stricto showed resistance against this azole. In Austria, Germany, and the United Kingdom posaconazole-resistance in all A. terreus isolates was higher than 10%, resistance against voriconazole was rare and absent for itraconazole.

Protothecosis in a patient with T cell lymphocytic leukemia

Human protothecosis is a rare infection caused by algae of the genus Prototheca. Prototheca wickerhamii has been recognized as the main species that causes infection in immunocompromised hosts with deficits in innate or cellular immunity. We report a case of persisting subcutaneous protothecosis in a patient with T-cell large granular lymphocyte leukemia, who also presented a history of disseminated histoplasmosis.

Biodiversity of species of Aspergillus section Fumigati in semi-desert soils in Argentina

The distribution of Aspergillus species in soil has been widely studied all over the world. The aim of this study was the phenotypic and genotypic characterization of species Aspergillus belonging to section Fumigati present in soils from two Argentinian semi-desert areas having different geological conditions. Altogether, 23 isolates belonging to Aspergillus section Fumigati were recovered and identified using a polyphasic approach including phenotypic and molecular identifications. Aspergillus fumigatus sensu stricto and Aspergillus fumigatiaffinis had the highest frequency, of occurrence while isolates closely related to Aspergillus udagawae and Aspergillus felis were rarely observed. A. fumigatiaffinis and isolates closer to A. udagawae were isolated for the first time from Argentinian soils and this is the first report on the occurrence of species belonging to the A. felis clade in South America. Recent scientific interests in biodiversity, as well as the increasing importance of aspergilli as causative agents of human and animal diseases increase the need to understand the diversity and occurrence of these fungi in nature.

A prospective international Aspergillus terreus survey: an EFISG, ISHAM and ECMM joint study

OBJECTIVES

A prospective international multicentre surveillance study was conducted to investigate the prevalence and amphotericin B susceptibility of Aspergillus terreus species complex infections.

METHODS

A total of 370 cases from 21 countries were evaluated.

RESULTS

The overall prevalence of A. terreus species complex among the investigated patients with mould-positive cultures was 5.2% (370/7116). Amphotericin B MICs ranged from 0.125 to 32 mg/L, (median 8 mg/L).

CONCLUSIONS

Aspergillus terreus species complex infections cause a wide spectrum of aspergillosis and the majority of cryptic species display high amphotericin B MICs.

Austromegabalanus psittacus barnacle shell structure and proteoglycan localization and functionality

Comparative analyzes of biomineralization models have being crucial for the understanding of the functional properties of biominerals and the elucidation of the processes through which biomacromolecules control the synthesis and structural organization of inorganic mineral-based biomaterials. Among calcium carbonate-containing bioceramics, egg, mollusk and echinoderm shells, and crustacean carapaces, have being fairly well characterized. However, Thoraceca barnacles, although being crustacea, showing molting cycle, build a quite stable and heavily mineralized shell that completely surround the animal, which is for life firmly cemented to the substratum. This makes barnacles an interesting model for studying processes of biomineralization. Here we studied the main microstructural and ultrastructural features of Austromegabalanus psittacus barnacle shell, characterize the occurrence of specific proteoglycans (keratan-, dermatan- and chondroitin-6-sulfate proteoglycans) in different soluble and insoluble organic fractions extracted from the shell, and tested them for their ability to crystallize calcium carbonate in vitro. Our results indicate that, in the barnacle model, proteoglycans are good candidates for the modification of the calcite crystal morphology, although the cooperative effect of some additional proteins in the shell could not be excluded.

[Genotyping of Cryptococcus neoformans/Cryptococcus gattii complex clinical isolates from Hospital "Dr. Julio C. Perrando", Resistencia city (Chaco, Argentina)]

Cryptococcosis is a fungal infection caused by yeast species of Cryptococcus genus, particularly Cryptococcus neoformans/Cryptococcus gattii species complex. The knowledge of the cryptococcosis casuistic in northeastern Argentina is scarce and there is no information about the molecular types circulating in this area. The aim of this study was to genotyping C. neoformans/C. gattii complex clinical isolates obtained at Hospital "Dr. Julio C. Perrando", Resistencia city (Chaco, Argentina), in order to determine species, variety and molecular type. During two years and one month 26 clinical isolates were studied. Using conventional and molecular methods one isolate was identified as C. gattii VGI type, and 25 isolates as C. neoformans var. grubii; 23 of these belonged to VNI type and two belonged to VNII type. This data is a contribution to the knowledge of cryptococcosis epidemiology in Argentina and the first report about C. neoformans/ C. gattii complex molecular types from clinical isolates in northeastern Argentina.

Aspergillus terreus complex: an emergent opportunistic agent of Onychomycosis

The incidence of onychomycosis due to non-dermatophyte moulds (NDM) is increasing. Aspergillus terreus is relatively undocumented as an agent of this fungal infection. The aim of this work is to show the prevalence of onychomycosis caused by A. terreus and to describe its clinical features. Nail samples were collected for microscopic examination and culturing in selective media. All cases of onychomycosis due to NDM were confirmed by a second sample. Aspergillus terreus isolates were identified through their morphological characteristics and using molecular methods. A total of 2485 samples were obtained. Positive cultures were obtained in 1639 samples. From 124 NDM confirmed cultures, 23 were identified as A. terreus (18.5%). Superficial white onychomycosis was the most frequent clinical pattern. A high percentage was found in fingernails. The prevalence of A. terreus in this study considerably exceeded the percentages reported by other authors. Onychomycosis due to A. terreus presents similar clinical patterns to those caused by dermatophytes, but is difficult to eradicate and is associated with less predictable treatment outcomes. Better knowledge of the aetiology of A. terreus may be important for accomplishing more accurate and effective treatment.

Evaluation of a multilayered chitosan-hydroxy-apatite porous composite enriched with fibronectin or an in vitro-generated bone-like extracellular matrix on proliferation and diferentiation of osteoblasts

The use of extracellular matrix (ECM) molecules from tissues is an interesting way to induce specific responses of cells grown onto composite scaffolds to promote adhesion, proliferation and differentiation. There have been several studies on the effects on cell proliferation and differentiation of osteoprogenitor cells cultured onto composites, either adding some ECM molecules or grown in the presence of growth factors. Other studies involve the use of osteoblasts cultured on a three-dimensional (3D) matrix, enriched with ECM molecules produced by the same cells grown previously inside the composite. Here, the effect of enrichment of a novel multilayered chitosan-hydroxyapatite composite with ECM molecules produced by osteoblasts, or the addition of 25 or 50 µg/ml fibronectin to the composite, on proliferation and differentiation of osteoblasts cultured on these composites was studied. The results showed an increase in the number of osteoblasts from day 1 of culture, which was higher in the group grown onto composites enriched with the highest concentration of fibronectin or with ECM molecules produced naturally by osteoblasts cultured previously on them, when compared with the control group. However, this increment tended to decline in all groups after day 7 of culture, the day when they reached the highest peak of proliferation. Differentiation expressed as alkaline phosphatase activity followed the proliferation pattern of the cells cultivated on the scaffolds. The results demonstrate the potential offered by these enriched 3D multilayered composites for improving their ability as bone grafting material.

[Trapped epidural catheter: reconstruction of computed tomography images]

A trapped epidural catheter without a knot is a rare complication. During placement of an epidural catheter for analgesia during labor, resistance made it impossible to position the catheter within the epidural space. A second catheter was inserted to provide the required analgesia. When the second catheter was removed, computed tomography (CT) revealed that the tip of the first catheter was close to the the right facet joint space. A second attempt to extract the catheter failed. In light of this situation, the patient was seated with the spine slightly bent to one side, a guidewire was inserted through the catheter lumen, and the catheter and guidewire were gently pulled; the catheter was extracted without causing the tip to break up. Three-dimensional CT reconstruction allowed the catheter tip and characteristics of the joint surfaces to be observed. We discuss protcols and alternative strategies that can be followed when an epidural catheter is difficult to remove, including the most appropriate images to use for guidance.

Prospective comparison of clinical and echocardiographic diagnosis of rheumatic carditis: long term follow up of patients with subclinical disease

OBJECTIVE

To determine the frequency of occurrence and long term evolution of subclinical carditis in patients with acute rheumatic fever.

DESIGN

Valvar incompetence was detected by clinical examination and Doppler echocardiographic imaging during the acute and quiescent phases of rheumatic fever. Patients were followed prospectively and submitted to repeat examinations at one and five years after the acute attack. Persistence of acute mitral and aortic lesions detected solely by echocardiography (subclinical disease) was compared with that of disease detected by clinical examination as well (thereby fulfilling the latest 1992 Jones criteria for rheumatic carditis).

SETTING

Three general hospitals with a university affiliation in Chile.

PATIENTS

35 consecutive patients fulfilling the revised Jones criteria for rheumatic fever. Clinical and echocardiographic examination was repeated in 32 patients after one year and in 17 after five years. Ten patients had subclinical carditis on admission, six of whom were followed for five years.

MAIN OUTCOME MEASURES

Auscultatory and echocardiographic evidence of mitral or aortic regurgitation during the acute attack or at follow up.

RESULTS

Mitral or aortic regurgitation was detected by Doppler echocardiographic imaging in 25/35 rheumatic fever patients as opposed to 5/35 by clinical examination (p = 0.03). Doppler echocardiography revealed acute valvar lesions in 10 of 20 rheumatic fever patients who had no auscultatory evidence of rheumatic carditis (subclinical carditis). Three of these subclinical lesions and three of the clinical or auscultatory lesions detected on admission were still present after five years of follow up, emphasising that subclinical lesions are not necessarily transient.

CONCLUSIONS

Doppler echocardiographic imaging improves the detection of rheumatic carditis. Subclinical valve lesions, detected only by Doppler imaging, can persist. Echocardiographic findings should be accepted as a major criterion for the diagnosis of rheumatic fever.

Escherichia coli membrane fluidity as detected by excimerization of dipyrenylpropane: sensitivity to the bacterial fatty acid profile

A coordinated study of membrane fluidity and fatty acid composition has been carried out in Escherichia coli W3110. The lipid acyl chain profile of the bacteria, altered by growing cells in steady state at 30, 37, 42, or 45 degrees C, was determined by gas chromatography of the fatty acid methyl esters. In parallel experiments, total membranes obtained from cells of the above-mentioned cultures were labeled with dipyrenylpropane and their relative fluidity was measured on the basis of the excimer to monomer fluorescence intensity ratio of the fluorophore. It has been found that, at constant assay temperature, fluidity determined with dipyrenylpropane decreases gradually with the growth temperature increment, from 30 to 45 degrees C. Interestingly, when fatty acid composition is taken into account, fluidity increases linearly in the range under study, with the proportion of unsaturated fatty acyl chains, both variables being highly correlated (0.924 </= r(2) </= 0.996). Our results show that dipyrenylpropane is a reliable and quantitative indicator of changes in membrane fluidity, driven by modifications in the acyl chain composition of bacterial lipids.

[Single-system ectopic ureters. A review of 19 cases]

Single system ectopic ureters are usually associated with multiple congenital abnormalities and the corresponding renal units is frequently abnormal. 19 cases of single system ectopic ureters were diagnosed and treated in our hospital during the last 20 years. The patients were less than 11 years old. The abnormality was bilateral in two cases and the 63% of all had associated malformations, being the anorectal abnormalities the most frequent. The incidence of reflux into the ectopic ureter was 57%, and the association to unilateral or contralateral renal agenesis, 26.3%. Thirteen ectopic ureters were reimplanted successfully into the bladder, and the cases of nonfunctioning kidneys were removed (nephroureterectomy). The follow-up period was 10 months to 14 years, developing the 68% of the cases without any complication and a good renal function. Two patients were transplanted due to a kidney failure. Diagnosis is often extremely difficult and requires a high degree of suspicion. This diagnosis may be incidental, and it may be made during investigation of patients with other malformations. An early diagnosis and treatment must be made in order to avoid a disturbance of renal function. We wish to point up the high incidence of reflux into the ectopic ureter and the high association to renal agenesis in the single system ectopic ureters in comparison with ectopic ureter of duplex system.

Spontaneous biliary perforation and necrotizing enterocolitis

A case of spontaneous bile-duct perforation in a 5-month-old boy with a history of necrotizing enterocolitis in his 1st week of life is reported. To our knowledge, this is the second case reported with such an antecedent, supporting a vascular etiology for some cases of spontaneous biliary perforation.

Fatty acid profile of Escherichia coli during the heat-shock response

The possible changes in the fatty acid profile of Escharichia coli during heat-shock have been investigated. Bacteria growing in steady-state at 30 degrees C were subjected to an abrupt temperature upshift to 45 degrees C and held at the high temperature for various periods of time in order to elicit the heat-shock response. Fatty acid compositions of lipids extracted from samples taken at different times after the temperature upshift, as well as from cultures in steady-state at 30 and 45 degrees C, were determined by gas-chromatography. It has been found that the total unsaturates to total saturates ratio decreases gradually during heat-shock and that 30 min after the temperature jump, the reduction is equivalent to 57% of the difference between ratios corresponding to steady-state cultures at 30 and 45 degrees C. Consistent with this remodeling of lipid acyl chains, there is a decrease in the excimerization rate of the fluidity probe dipyrenylpropane incorporated into sonicated E. coli lipid extracts. Such modifications occur within the time-span of the heat-shock response, as judged from our previous measurements of the kinetics of change in heat-shock proteins induction ratio. Together, these results indicate that the control of membrane fluidity during the heat-shock response can be accounted for, at least in part, by an important change in the fatty acid composition of Escherichia coli lipids.

[Laparoscopic transsection of Ladd's bands: a new indication for therapeutic laparoscopy in neonates]

Within the last ten years and by the introduction of some new instruments, laparoscopy is a safe and effective method that has been further extended in children. We report our experience in the treatment of laparoscopy on a seven day old newborn affected by malrotation with an intermittent duodenal obstruction. The treatment consisted of a duodenal liberation after the section was easily performed in congenital Ladd's bands. The spiral twists of the small intestine found in the upper gastrointestinal series, disappeared in a new study done after surgery. We consider this operation as a new indication for an operative laparoscopy. It allows a good visualization of this congenital abnormality, and it is easy to perform with a significantly reduced operative trauma.

Long-gap esophageal atresia: reconstruction preserving all portions of the esophagus by Schärli's technique

For distances of over 4-5 cm, esophageal replacement is almost always necessary in esophageal atresias. We present the technical details and describe our experience with esophageal reconstruction by elongation of the lesser curvature (Schärli's technique) in four cases of very long atresias. A retrosternal transposition was made without a thoracotomy in two children, and an orthotopic mediastinal route through a right thoracotomy was done in two others. There were two main complications: anastomotic leaks in three patients that closed spontaneously, and too-rapid gastric emptying, resulting in dumping symptoms that improved with time and diet. One patient developed an anastomotic stricture that responded to bouginage, while another had temporary feeding problems. Esophageal reconstruction by elongation of the lesser curvature provides a relatively simple method of esophageal replacement in children in that all portions of the esophagus are preserved. We propose this technique for early establishment of esophageal continuity in neonates.

The interaction of phospholipase A2 with liposomes: an immunological approach to its study

Porcine pancreatic phospholipase A2 (PLA2) has been incubated for 2 hours at 34 degrees C with rabbit anti-pig pancreatic PLA2 polyclonal antiserum in the absence or presence of phosphatidylcholine liposomes in different physical states. Subsequent assay of hydrolysis -triggered through addition of 5 mM Ca2+- at 34 degrees C, shows that preincubation with antiserum in the presence of 1,2-dimyristoyl-3-sn-phosphatidylcholine liquid-crystalline vesicles, renders the PLA2 activity undetectable, similarly to what is found if preincubation is carried out in the absence of liposomes. In contrast, 1,2-dipalmitoyl-3-sn-phosphatidylcholine liposomes, which at 34 degrees C are in the gel-phase, protect the enzyme from the antiserum effect. The results are consistent with a stronger binding of PLA2 to gel phase, as compared to liquid crystalline vesicles and suggest that through the physical interaction with liposomes in the gel state, the enzyme is shielded from reaction with the antibodies. Taking into account the characteristic hydrolysis profiles of vesicles in different physical states, it can be concluded that the above interpretation agrees with the proposal that PLA2-membrane association promotes the interfacial activation of the enzyme.

Role of type X collagen on experimental mineralization of eggshell membranes

Type X collagen is a transient and developmentally regulated collagen that has been postulated to be involved in controlling the later stages of endochondral bone formation. However, the role of this collagen in these events is not yet known. In order to understand the function of type X collagen, if any, in the process of biomineralization, the properties of type X collagen in eggshell membranes were further investigated. Specifically, calvaria-derived osteogenic cells were tested for their ability to mineralize eggshell membranes in vitro. Immunohistochemistry with specific monoclonal antibodies was used to correlate the presence or absence of type X collagen or its propeptide domains with the ability of shell membranes to be mineralized. The extent of mineralization was assessed by Von Kossa staining, scanning electron microscopy and energy-dispersive spectroscopy. The results indicate that the non-helical domains of type X collagen must be removed to facilitate the cell-mediated mineralization of eggshell membranes. In this tissue, intact type X collagen does not appear to stimulate or support cell-mediated mineralization. We postulate that the non-helical domains of type X collagen function in vivo to inhibit mineralization and thereby establish boundaries which are protected from mineral deposition.

Cantrell's pentalogy. Report of four cases and their management

Four neonates with the uncommon Cantrell's pentalogy seen in our hospital within a 6-month period without any apparent factor in common are described, with a review of the world literature. The first case was diagnosed prenatally at 15 weeks' gestation, the earliest intrauterine finding in the literature. The occurrence of imperforate anus with the syndrome, observed in one of the cases, has not been previously reported. Two were operated upon and only one of the four survived. This high mortality was confirmed by similar cases reported by other authors.

[Solid ovarian tumors in childhood]

We evaluate our experience in solid ovarian tumors at the Children's Hospital La Fe. The main aims of the study were finding out relevant clinical data for a correct clinical approach, and the optimal surgical attitude in order to obtain tumor relieving with preservation of fertility when possible. A review of 28 girls under 14 years with solid ovarian tumors was carried out. Previous history, initial symptoms and signs, analytical and radiological explorations, treatment and evolution were analysed. 17 benign and 11 malignant tumors were found. Main clinical data were acute abdominal pain and palpation of a mass. Surgery was performed in all of them: salpyngo-oophorectomy in 23 and oophorectomy in 5, with tumoral resection. All patients survive, with periodic follow-up. We remark the frequency of acute abdominal pain as initial symptom of an ovarian tumor, and the importance of a surgical attitude that, intending to be curative, would preserve fertility.

[Our experience in portal cavernomatosis in childhood: cross-sectional study and analysis of results]

A retrospective and transversal study of our patients with portal cavernomatosis is developed, with the aim of comparing the evolution and the present status of the patients that have undergone different therapeutical approaches. Between 1975 and 1995, 15 patients with portal cavernomatosis have been treated. Personal history, signs and symptoms at the moment of diagnosis, and treatment were analyzed. Now, the controls have been made by physical examination and ECO-Doppler of the espleno-portal system. In 6 cases the absence of bleeding made surgery unnecessary. In the 9 patients with digestive haemorrhage, it could be controlled pharmacologically, with a later surgical approach. Now, all non-operated and 6 operated patients show splenomegaly, without bleeding. The ECO-Doppler shows colateral flow, the splenomegaly in the non-operated and the surgical shunts and the hepatofugal circulation in the operated patients. Looking at our results, we believe that prophylactic surgery is not indicated. In those cases of digestive bleeding, surgery after the complete resolution of the acute disease shows good results at a short and long term.

Congenital intrahepatic portocaval shunt associated with trimethylaminuria

A case of congenital portal-systemic shunting due to an intrahepatic connection diagnosed by ultrasound scanning and color Doppler in an 8-month-old girl is reported. She began to manifest trimethylaminuria 3 years later. At 7 years of age, she is asymptomatic without therapeutic measures except for diet. This is the seventh reported case and the third in a child to our knowledge.

[Ureteral ectopia in pediatric age: treatment and evolution in 55 cases]

In the last twenty years 55 children with ureteral ectopia were diagnosed and treated in our Hospital. Thirty seven of them were female (67.3%) and they presented the urinary tract infection like the most frequent symptomatology. Seven children were diagnosed during the first days after being born because the detection of hydronephrosis in the antenatal ultrasound; 36 were associated with complete ureteric duplication (65.4%) and the other 19 with single system (34.6%). Congenital abnormalities associated were seen in 14 patients with more frequency in those which presented single-system ectopic ureter (12/14), being the imperforate anus and the kidney agenesia those the most incidence. The most frequent points of opening were the bladder neck and posterior uretra. Diagnostic work-up included some radiological studies (abdominal ultrasound, intravenous urography, sequence mictional cystourethrography and vaginogram), isotopical tests, meticulous genital exploration, cystoscopy and vaginoscopy. 49.1% underwent conservative surgical treatment (7 ipsilateral ureteroureterostomy and 20 ureteral reimplantation) and 50.9% underwent total or partial nephroureterectomy, being the type of treatment depended on functionality of renal units. After treatment, 74.5% had not any incident; among all postsurgical complications, reflux reappearance was the most frequent (3 cases).

[The use of color doppler sonography of the acute scrotum in children]

The differential diagnosis of the causes of acute scrotum only by clinical means, is often very difficult and supposes the risk of making mistakes, which leaves to several unnecessary surgical explorations. By Colour Doppler Sonography we get some information about testicular flow that helps us in the diagnosis. During the last two years 72 consecutive cases of acute scrotum in children younger than 13 years old, were seen in our hospital emergency department. They all underwent testicular bilateral sonography with color flow imaging using a 7.5 MHz linear array transducer (Model Sonolayer Toshiba SSH-140 A). The sonographical diagnosis were: 45 epididymo-orchitis (62.5%), 8 testicular torsions (11%), 7 torsions of the appendix of testis (9.7%), 7 normal explorations (9.7%), 4 acute idiopathic scrotal oedema (5.5%) and a Henoch-Schönlein purpura (1.38%). Doppler examination showed a 97.2% sensibility and 72.2% specificity in the diagnosis of epididymo-orchitis and 88.88% sensibility and 100% specificity in the diagnosis of testicular torsion. The Colour Doppler Sonography should not minimize importance to the clinical explorations, but is very useful for the diagnosis of acute scrotal process, overcoat in inflammatory diseases.

[Treatment with Ethibloc of lymphangiomas and venous angiomas]

Lymphangioma and venous angioma are a group of pathological entities which have required surgical treatment since years. Extension, localization and poor delimitation of some lesions have resulted in technical difficulties and serious complications. Our group began the sclerosing therapy with an injection of fibrin adhesive and, due to the lack of response in the first patient, a program with Ethibloc as an alternative substance was developed. We present 10 cases, 4 lymphangiomas and 6 venous angiomas. In 50% of our patients one single session of sclerotherapy was made, in 25% two sessions, and in the rest 25% three. From 10 cases, 4 are still on treatment, complete remission in 5 cases, and good evolution in one case (mixed lymphangioma). As a long-term complication, we have noticed fistulization in 3 cases, and expulsion of the sclerosing agent. In our experience, percutaneous sclerosis with Ethibloc should be the first therapeutic alternative.

[Neonatal intravaginal testicular torsion in an undescended testis]

We report a case of intravaginal testicular torsion with an unusual debut in a 30 day old patient which had undescended testis. We emphasize the need of a complete physical exploration of the child that go to the emergency service with inspecific symptoms of abdominal pain, and supposing the hemiscrotum was empty, is essential to reject a torsion of a cryptorchidic testicle. An immediate surgery is necessary in order to diagnose and treat this disturbance.

Membrane fluidity of Escherichia coli during heat-shock

The excimer-forming fluorophore dipyrenylpropane has been used to measure the relative fluidity of total membranes isolated from Escherichia coli grown at 30 or 45 degrees C, or exposed to a heat-shock from 30 to 45 degrees C for various periods of time. Parallel experiments were performed using [35S]methionine pulse-labeling of cells, to study the induction of heat-shock proteins (HSPs) at different times after the sudden change in E. coli growth-temperature from 30 to 45 degrees C. Results suggest that upon an abrupt temperature upshift from 30 to 45 degrees C, membrane fluidity adjustment to the steady-state level at the high temperature, takes place during the E. coli heat-shock response.

Activity of phospholipase A2 on a fluorescent substrate incorporated into non-hydrolyzable phospholipid liposomes

The activity of phospholipase A2 (PLA2) on phospholipid liposomes depends on the physicochemical properties of the aggregated substrate, which are subject to continuous modification by the products released during hydrolysis. We propose here an experimental design that, by means of the incorporation of a fluorescent substrate at very low molar ratio (< or = 1:500) into a nonhydrolizable liposomal matrix of 1,2-dihexadecyl-sn-glycero-3-phosphocholine (DHPC), allows the study of hydrolysis by porcine pancreatic phospholipase A2, in virtual absence of physical perturbations of the lamellar phase, by the released products. We have been able to measure immediate hydrolysis of the fluorescent substrate 1,2-di-[omega(1'-pyreno)-decanoyl]-sn- glycero-3-phosphocholine when the sonicated liposomal matrix is in the gel phase. In the liquid crystalline state, in contrast, hydrolysis is very poor even after 80 min of adding the enzyme. Both in the gel and liquid-crystalline phases, incorporation of unlabeled PLA2 products activates the hydrolysis rate to comparable levels. It appears that the conformation adopted by the substrate immersed in the gel or liquid crystalline matrix is especially important in determining its susceptibility to hydrolysis in the absence of products.

Calcium ions reverse a latency period induced by bovine serum albumin in the time course of phospholipase A2 action on 1,2-dipalmitoyl-sn-glycero-3-phosphocholine liposomes

The time course of hydrolysis of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine liposomes in the gel phase catalyzed by porcine pancreatic phospholipase A2 was studied at 1 mM NaCl and variable CaCl2 concentrations, in the presence of delipidated bovine serum albumin. It has been found that the duration of the latency induced by bovine serum albumin shows an inverse dependence with CaCl2 concentration. As we showed previously, the induction of a lag phase by bovine serum albumin is related to its ability to sequester the fatty acid newly released by hydrolysis. Based on this and on our observation that there is an inverse dependence between the length of the latency period and the interfacial calcium ion concentration, it is interpreted that, while a direct effect of bovine serum albumin is the diminution of the liposome negative surface charge density by sequestration of the fatty acid released during hydrolysis, an indirect effect could be the decrease in the surface Ca2+ concentration. This, in turn, should diminish the enzyme binding to the lipid-water interface. The appearance of a latency phase seems to be the final consequence of these events.

[Renal scintigraphy with captopril in the evaluation of renovascular hypertension]

The administration of an angiotensin-converting enzyme (ACE) inhibitor transitorily reduces the GFR in a kidney with renal artery stenosis, effect that can be ascertained with scintigraphic studies using ACE inhibitors. We evaluated the clinical usefulness of captopril renography (CR) in the diagnosis of renovascular hypertension (RVH) in 51 hypertensive patients in which this diagnosis was suspected. All subjects underwent angiography and RVH was diagnosed when renal artery stenosis exceeded 60%, there was lateralization of renal vein renin or there was a concordant clinical outcome. Renography was performed 15 minutes after Lasix administration, using Tc-99m DTPA, before and 60 minutes after the oral administration of 50 mg of captopril. The scintigraphic criteria for a positive test were a decreased split renal function, a delayed peak uptake, a decreased excretion of DTPA and a prolonged transit time. In three of 28 patients in whom angiography discarded RVH, CR was positive. In the 23 patients with confirmed RVH, CR was positive in 10 of 12 with unilateral stenosis, in 3 of 8 with bilateral stenosis and 1 of 3 with stenosis in a transplanted kidney. The overall sensitivity and specificity of the test for RVH was 60.9% and 89.2% respectively. There were no changes in blood pressure or adverse effects after captopril administration. We conclude that CR in RVH is useful to select patients for further studies (angiography) and to perform a functional interpretation of angiographic alterations.

Partial biochemical and immunochemical characterization of avian eggshell extracellular matrices

There is evidence to suggest that extracellular matrix molecules, such as proteoglycans, are involved in the regulation of mineral deposition in calcifying tissues. One mineralizing system which is characterized by extremely rapid mineralization is the hen eggshell. This eggshell consists of a pair of nonmineralized eggshell membranes subjacent to the calcified eggshell proper; the eggshell proper is organized into palisades (columns) of mineralized matrix separated by pores. Between the membranes and the shell proper are compacted foci of tissue called mammillary knobs, which are thought to be sites where mineralization is initiated. Previous work from this laboratory has shown the presence of types I, V, and X collagen in the shell membranes. To address the question of the possible role of proteoglycans and glycosaminoglycans in mineralization of the eggshell, two approaches were used. First, immunohistochemistry was performed with monoclonal antibodies to various proteoglycan and glycosaminoglycan epitopes. This analysis indicates that different glycosaminoglycans are localized to discrete regions within the eggshell. Dermatan sulfate is present within the matrix of the shell proper and, to a lesser extent, the mammillary knobs and the outer portion of the shell membranes. In contrast, keratan sulfate is found in the shell membranes and prominently in the mammillary knobs. Interestingly, different keratan sulfate antibodies immunostain distinct regions of the eggshell, which suggests that various types of keratan sulfate are distributed differently. The second approach utilized was to extract the eggshell membranes and recover anionic molecules by anion-exchange chromatography. This resulted in the extraction of material which was recognized by antibodies to keratan sulfate, but not to chondroitin sulfate. This material was very large, as evidenced by its elution in the void volume of a Sepharose CL-2B column. The large size may be due to the extensive cross-links known to occur in the eggshell. If eggshell membranes are extracted at elevated temperature, the material recovered is of much smaller size. These results indicate that molecules recognized by antibodies to glycosaminoglycans are present in the eggshell, and their localized distribution relative to the calcified matrix suggests that they may be involved in the regulation of mineral deposition.

[Sexually transmitted diseases: notification in Chile, in the V region and in the Vinã Del Mar-Quillota health service (1977-1988)]

Reports of sexually transmitted diseases in the Vth Region of Chile from 1977 to 1988 were analyzed and compared to nationwide reports and to figures for the Viña del Mar-Quillota area. Overall rates of syphilis decreased during the period. In contrast both number of cases and risk of disease increased for gonorrhoea. Risk of syphilis and gonorrhoea was highest in the Vth Region. HIV infection is increasing, especially in the area covered by the Health Service in Viña del Mar-Quillota. Sexually transmitted diseases not subject to reports were screened along with routine examinations for cancer of the cervix. Infection rates of 9.9% for trichomona and 1.09% for candida were thus detected.

Dependence on neutral salt concentration of the latency phase in the time course of hydrolysis of dimyristoylphosphatidylcholine liposomes by phospholipase A2

The time course of the hydrolytic action of porcine pancreatic phospholipase A2 on sonicated dimyristoylphosphatidylcholine liposomes in the presence of variable NaCl concentrations has been studied at temperatures between 17 and 36 degrees C; at these temperatures liposomes are in the gel phase. At a NaCl concentration of 10 mM, the hydrolysis shows a small and constant lag period of 6-8 min at all temperatures within this range. As the temperature is raised into the liquid crystalline range, the latency phase lengthens monotonically so that at 36 degrees C it reaches 55 min. An increase in the NaCl concentration to 1 M makes the lag period longer at all temperatures studied, with the exception of the phase transition range (near 24 degrees C); within this temperature range, a small reduction in the lag time is observed. The increase in the length of the latency period at high salt concentrations may be due to screening of the negative surface charge generated by the nascent fatty acid which seems to be essential for the efficient interfacial binding of the enzyme. In the phase transition range of the lamellae, the unfavorable effect of high salt concentrations on the electrostatic binding of the enzyme appears to be overcome by another type of interaction. Recent findings raise the possibility that this interaction could be hydrophobic in nature.

[Sexually transmitted diseases: epidemiological characteristics of cases notified in the health service of Viña del Mar-Quillota]

During 1987 and 1988 sexually transmitted diseases affected 87.2 per 100,000 inhabitants of the Viña del Mar-Quillota area. At all ages rates were 3.8 times higher in males compared to females. Gonorrhoea, syphilis and non gonorrheal urethritis accounted for most cases. In males, 82% of cases corresponded to gonorrhoea, in females 50% corresponded to gonorrhoea and 50% to syphilis. Rural and urban figures were not significantly different, except for HIV infection which was predominantly urban. Rates of different infections peaked at different ages: HIV between 30 and 39, gonorrhoea from 15 to 29, syphilis from 40 to 49 and after 60 and non gonorrhoeal urethritis from 15 to 59. In a survey of affected subjects 85% manifested to be heterosexual, 10% omitted a response.

The interfacial calcium ion concentration as modulator of the latency phase in the hydrolysis of dimyristoylphosphatidylcholine liposomes by phospholipase A2

Analysis of the time course of hydrolysis of dimyristoylphosphatidylcholine liposomes catalyzed by porcine pancreatic phospholipase A2 at 18 degrees C shows that, in the presence of 10 mM NaCl, the length of the latency period in the presteady-state phase increases from 3 to 10.5 min when the CaCl2 concentration is reduced from 15 to 1 mM. This inverse dependence of the lag period on calcium ion concentration is seen more readily at 1 M NaCl, where the induction time changes from 13.5 to 42 min by decreasing the concentration of CaCl2 from 15 to 1 mM. To interpret these results, we took into account the small amount of fatty acid that is produced during the latency phases. The fatty acid generates a negative surface electrostatic potential and makes the interfacial concentration of calcium ions different from the concentration in the bulk solvent. Variations in the analytical concentrations of NaCl and CaCl2 affect both the interfacial calcium ion concentration and electrostatic potential, as estimated theoretically from Grahame and Boltzmann equations. According to these estimates, the length of the latency period diminishes with the increase of the interfacial calcium concentration, but does not show any logical dependence on the change in surface electrostatic potential.

The local anaesthetic tetracaine as a quencher of perylene fluorescence in micelles

At neutral pH the local anaesthetic tetracaine hydrochloride quenches the fluorescence of the lipophilic dye perylene incorporated into non-ionic micelles. The process follows the Stern-Volmer equation, suggesting that quenching occurs through encounter of fluorophore and quencher. As the pH is lowered from 5 to 1, the apparent quenching constant decreases sigmoidally, the midpoint of the curve being at pH 2.3, close to the pK value characterizing the ionization of the anaesthetic aromatic butylamino group. Quenching is completely reversed below pH 1. These results show that the ability of tetracaine to quench the fluorescence of perylene incorporated into micelles depends on the absence of charge on its aromatic amine. Quenching was also studied in homogeneous dioxane-water solution. In this system the quenching constant also decreases sigmoidally as the pH is lowered. The infection point of the curve is nearly coincident with the pK of tetracaine butylamino group in the same partially non-aqueous medium. Protonation of this group induces 60% reversal of the quenching, suggesting that the main mechanism of fluorescence extinction could be the electron transfer from unprotonated tetracaine aromatic amine to perylene in the excited state. However, an additional process which remains operative even when such an amino group is positively charged must also be involved. It can be concluded that the complete reversal of tetracaine quenching of perylene fluorescence in micelles induced by low pH is due to the inability of the anaesthetic to become partitioned into micelles upon protonation of its aromatic amine. In contrast, at neutral pH the local anaesthetic is able to reach the micelle non-polar core where perylene is located. This is consistent with the models, suggesting that the membrane-bound tetracaine assumes a rod-like configuration parallel to the surface normal with the aromatic butylamino group located into a highly hydrophobic region.

[Value of 2-dimensional echocardiography in infective endocarditis]

We analyzed the two dimensional echocardiograms (2D echo) of 41 patients with infective endocarditis (IE). The diagnosis of endocarditis was based on typical clinical findings, positive blood cultures or anatomical findings at operation or necropsy. Age ranged from 21 to 73 years. Endocarditis was localized in a native valve in 30 patients (aortic 18, mitral 11 and tricuspid 1), a biologic prosthesis in 9 (mitral 4, aortic 4, unknown 1) and a mechanical valve in 4 (aortic 3, mitral 1). The echocardiogram showed vegetations, valve rupture or abscess in 83% of IE in native valves, 56% of IE in biologic prosthesis and 25% of IE in mechanical valves (p less than 0.05, native vs prosthetic valves). The sensitivity of 2D echo was studied in 27 subjects with known anatomical findings. It was 79% for vegetations (mitral 91%, aortic 72%, NS), 53% for valve rupture (mitral 83%, aortic 33%, p less than 0.05) and 70% for abscess. Specificity was over 89% for all lesions. Systemic embolism occurred in 41% of patients with vegetations and in 25% of those without (p = 0.07).

1H-NMR of phosphatidylcholine liposomes at low p2H in the presence of a paramagnetic shift reagent

1H-NMR spectra of egg phosphatidylcholine liposomes in 2H2O were obtained at several p2H values in the presence of 10 mM PrCl3 added after sonication of the phospholipid. It has been found that as the p2H is lowered below 2, the two distinct signals corresponding to the outer and inner phospholipid trimethylammonium groups which arise by the shifting effect of the paramagnetic cation on the external surface of vesicles, tend to coalesce into a single, high-field peak, at the position corresponding to the internal, non-shifted -N+ (CH3)3 protons. These results can be interpreted to mean that the shifting effect of Pr3+ on phosphatidylcholine NMR spectra, is due to electrostatic interaction between the lanthanide and the ionized group of the lipid. At low p2H, as the phosphodiester becomes protonated, the paramagnetic cation is no longer attracted by the liposome surface and its shifting effect on the phospholipid NMR signals disappears. The plot of the p2H dependence of the chemical shift of the outer trimethylammonium resonance of phosphatidylcholine liposomes with praseodymium ions present only on the outside of vesicles, results in a sigmoidal titration curve with its midpoint at p2H 1.5. In contrast, the inner signal is not affected by p2H. If coalescence of signals is considered as indicative of complete protonation of the phosphate moiety, the value of 1.5 can be taken as the apparent pK for the ionization of that group under the experimental conditions employed, i.e., 10 mM PrCl3 in 2H2O. That the low p2H-induced merging of the signals is reversible, is shown by the reappearance of the two peaks when the p2H of the phospholipid dispersion is raised from 1 to 5.7. Since the recovery of the trimethylammonium signal splitting indicates that Pr3+ has remained excluded from the liposome inner compartment, these experiments also demonstrate that the vesicles have not been disrupted by exposure to such an extreme acidic condition as p2H 1.

Induction of a latency period in the time-course of phospholipase A2 action on dipalmitoylphosphatidylcholine liposomes in the gel phase

The hydrolysis of dipalmitoylphosphatidylcholine liposomes by porcine pancreatic phospholipase A2 was studied at 31 degrees C, i.e., with the substrate in the gel phase. Addition of delipidated bovine serum albumin to the assay medium induces the appearance of a latency phase in the time course of the enzymatic action. The lag period can be abolished by addition of free palmitic acid whereas no reversal by lysolecithin is found. The generation of a latency period by albumin appears to be due to its ability to sequester the palmitic acid newly released by the phospholipase A2 catalysis. Thus, the nascent fatty acid seems to be an essential activator of the enzymatic process.

The effect of pH on the phase transition temperature of dipalmitoylphosphatidylcholine-palmitic acid liposomes

The shift in the gel-liquid crystal phase transition temperature (tm) of dipalmitoylphosphatidylcholine liposomes induced by incorporation of 10 mol% palmitic acid, was measured by 90 degrees light scattering at different bulk pH values. It has been found that the tm shift decreases sigmoidally from 4.7 to -0.3 degrees C as the bulk pH is raised from 5 to 11. Since it is in this range that the carboxyl group of a membrane-bound fatty acid should ionize, our results can be interpreted to mean that there is relationship between the tm shift and the degree of dissociation of palmitic acid, the uncharged fatty acid increasing tm and its conjugate, anionic form, slightly decreasing the transition temperature of dipalmitoylphosphatidylcholine liposomes. The experimental results are fitted by a modified form of the Henderson-Hasselbach equilibrium expression which takes into account the effect of the anionic fatty acid on the surface potential and hence, on the surface pH of liposomes, according to Gouy-Chapman and Boltzmann equations, respectively. Best fit between theory and experiments is found when the intrinsic interfacial pK of palmitic acid is set equal to 7.7. This high pK value can be explained as due to the effect of the lower dielectric constant of the interfacial region, as compared to bulk water, on the acid-base dissociation of the carboxyl group. The results presented here show that upon incorporation of palmitic acid, the phase transition of dipalmitoylphosphatidylcholine bilayers becomes extremely sensitive to changes of pH in the vicinity of the physiological range. This property is not shown by the pure phospholipid bilayers in the same pH range.

Effect of LiCl on differentiation of mouse embryos beyond the blastocyst stage

In order to test the effect of Li+ on cell differentiation, 2-cell embryos were cultured in vitro with or without Li+ to the blastocyst stage and then, in a "implantation" culture medium, with or without Li+, up the early egg-cylinder stage. Our results show: 1) that Li+ in the preimplantation medium diminishes "implantation" success significantly; 2) that trophoblastic vesicles, produced by culturing preimplantation embryos with Li+, do not generate an inner cell mass when further cultured in "implantation" medium; 3) that the ultrastructure of "implanted" embryos is similar in all experimental series.

The effect of neutral and charged micelles on the acid-base dissociation of the local anesthetic tetracaine

The influence of surfactant micelles on the acid-base dissociation of the charged tertiary amino group of the local anesthetic, tetracaine, has been investigated. From measurements of tetracaine fluorescence as a function of bulk pH, apparent pK values of 6.88, 7.58 and 9.92 were found in the presence of cationic, neutral and anionic micelles, respectively, in 10 mM NaCl. These values are considerably displaced with respect to the pK in aqueous solution which is 8.26. Such large shifts can be attributed to the effect of the surface polarity and electrical potential on the dissociation behavior of the anesthetic bound to micelles. It can be expected that the acid-base dissociation of a local anesthetic adsorbed to nerve fibers will also be affected by the properties of the membrane surface. Thus, it is suggested that the influence of the interfacial region on the pK of surface-bound molecules should not be disregarded when estimating the proportion of charged and uncharged forms of local anesthetics interacting with axonal membranes.