Immunobiological role of llama heavy-chain antibodies against a bacterial beta-lactamase.

In 1993, a fraction of antibodies (Abs) devoid of L chain was found naturally occurring in the Camelidae. They were found to lack L chains, as well as the first constant heavy-chain domain (CH(1)) and therefore they were named "heavy-chain Abs" (HCAbs). Subsequent studies focused on the functional, structural and biochemical properties of recombinant variable fragments (rVHHs) of HCAbs. It was stated that rVHHs have an augmented capacity to interact with "partially hidden" epitopes, like enzymes active sites, and have an increased stability to thermal and chemical aggression. It has been suggested that these unconventional Abs could represent an evolutionary advantage, being more efficient than conventional Abs to inhibit microbial enzymes, and thus exerting a more protective immune response against pathogens. The present work focuses on the immunobiological role of HCAbs, in their capacity to inhibit microbial enzymes. Two animal models were selected, comprising a model for common vertebrates without HCAbs (rabbits), and a model for vertebrates with both conventional and unconventional Abs (Lama glama). A recombinant bacterial beta-lactamase (CTX-M-2) was selected as the microbial enzymatic antigen. After conventional immunization schedules, neither serum titers nor serum inhibitory capacity showed significant differences when rabbits and llamas were compared. These results indicate that the a priori assumption that the adaptive immune system of camelids could be better "prepared" to respond to bacterial enzymes because of the presence of HCAbs, is not always accurate. Furthermore, when the different llama antibody isotypes and subclasses were purified, it was demonstrated that the inhibitory capacity of total serum was due exclusively to IgG(1). HCAbs not only failed to inhibit CTX-M-2, but instead they activated its enzymatic activity. Altogether, these results indicate that the hypotheses extrapolated from the rVHHs properties need to be revised; the real role of HCAbs in vivo remains unknown, as well as their evolutionary cause.

Ultrasonic anatomical study of the lesser omental sac: a pictorial essay.

The peritoneal and visceral limits of the lesser omental sac have been studied by ultrasound in ten patients with gross ascites. Ascitic fluid provides necessary contrast and ultrasound examination gives valuable anatomic information. A few pathologic examples are also studied.

Acute fatty liver of pregnancy: CT evaluation. Case report.

CT scans of two patients with acute fatty liver of pregnancy were reviewed in conjunction with the clinical evolution of this uncommon and potentially fatal disorder. In each of the CT scans, liver density measurements were less than those of the spleen. While the findings are non-specific, in the proper clinical context they are highly suggestive and may be the sole method of diagnosis, as these patients often have coagulation problems which rule out liver biopsy. It is an important diagnosis, as the high maternal and fetal mortality rates appear to be considerably reduced by early foetal delivery.

[Ultrasonographic study of retroperitoneal and abdominopelvic hematomas]. / Etude ultrasonographique des hématomes rétropéritonéaux et abdomino-pelviens.

A sonographic diagnosis was obtained in 33 hematomas encountered in conditions of emergency. Most hematomas were related to anticoagulant therapy. Most hematomas were located within the psoas muscle sheath, hematomas of the abdominal wall and Retzius'cavum. Follow-up examination of non operated hematomas show a progressive decrease of echogenicity.

[Comparative contribution of ultrasonography and tomodensitometry in the diagnosis of retroperitoneal adenopathies]. / Apport comparé de l'ultrasonographie et de la tomodensitométrie dans le diagnostic des adénopathies rétropéritonéales.

CT and sonography were compared in 78 cases of retroperitoneal lymph nodes. The results obtained with both methods are similar. Thus, ultrasound can be chosen as the first procedure in the evaluation of retroperitoneal lymph nodes. CT will be used as a complement in case of technically insufficient sonograms.

[Echographic diagnosis of peritoneal metastases in patients with ascites]. / Le diagnostic échographique des métastases péritonéales chez les malades ascitiques.

A prospective study of 14 malignant ascites examined with high frequency ultrasonic probes enabled he authors to achieve a diagnosis of peritoneal metastases in 78% of cases. Peritoneal metastases appear as areas of peritoneal thickening or scalloping, as nodules, with sometimes a strong bulging, and as intestinal masses. Soft part ultrasound should be employed systematically in the diagnosis and follow up of malignant ascites.

[Acute fatty liver of pregnancy. Apropos of 4 cases: contribution of x-ray computed tomography]. / Stéatose hépatique aiguë gravidique. A propos de 4 cas: apport de la tomodensitométrie.

Acute fatty liver of pregnancy is a disease of the third trimester, generally considered to be rare and to have a grave prognosis. Histologically the characteristic fine droplet steatosis usually produces distinct vacuolization. Successful treatment depends on accurate diagnosis and early delivery. Computed tomography is of value in the diagnosis of fatty liver through liver and spleen attenuation value measurements. We reviewed 4 cases of acute fatty liver of pregnancy. Computed tomography was performed in two cases and was very helpful in the diagnosis of this condition.

[Ultrasonography and x-ray computed tomography in the diagnosis of intra-abdominal textiloma. Apropos of 12 cases]. / Apport de l'échographie et de la scanographie dans le diagnostic des textilomes intra-abdominaux. A propos de 12 cas.

Feared by every surgeon, retained surgical sponges (or gossypiboma) are rare iatrogenic entities. Ultrasonography and computed tomography are very valuable, providing an immediate answer in the majority of cases. We report 12 cases of intra-abdominal retained surgical swabs. The ultrasonic pattern was made whether of a large poorly echogenic mass with a hyper-echogenic center and sharply delineated posterior acoustic shadow (7 cases) or of a large acoustic shadow posterior to a solitary highly echogenic area (4 cases). Computed tomography demonstrated whether large peripherally enhanced cystic mass associated with serpiginous or spongiform central area (5 cases) or heterogeneous abscess-like fluid mass.

[Imaging of the transplanted liver]. / Zobrazenie transplantovanej pecene.

The study brings about the newest information on possibilities of imaging the liver, its vessels, biliary ducts and further organs in coincidence with liver transplantation. (Fig. 7, Ref. 39.)

Activity modulation of microbial enzymes by llama (Lama glama) heavy-chain polyclonal antibodies during in vivo immune responses.

Since they were first described in 1993, it was found that recombinant variable fragments (rVHHs) of heavy-chain antibodies (HCAbs) from Camelidae have unusual biophysical properties, as well as a special ability to interact with epitopes that are cryptic for conventional Abs. It has been assumed that in vivo raised polyclonal HCAbs (pHCAbs) should behave in a similar manner than rVHHs; however, this assumption has not been tested sufficiently. Furthermore, our own preliminary work on a single serum sample from a llama immunized with a ß-lactamase, has suggested that pHCAbs have no special ability to down-modulate catalytic activity. In this work, we further explored the interaction of pHCAbs from four llamas raised against two microbial enzymes and analyzed it within a short and a long immunization plan. The relative contribution of pHCAbs to serum titer was found to be low compared with that of the most abundant conventional subisotype (IgG(1)), during the whole immunization schedule. Furthermore, pHCAbs not only failed to inhibit the enzymes, but also activated one of them. Altogether, these results suggest that raising high titer inhibitory HCAbs is not a straightforward strategy - neither as a biotechnological strategy nor in the biological context of an immune response against infection - as raising inhibitory rVHHs.

Ultrasound study of adenopathies within the hepatoduodenal ligament: the "rosebud" pattern.

In about 10% of lymphopathies with extensive retroperitoneal adenopathies, adenopathies are also encountered within the hepatoduodenal ligament. When large, such adenopathies, which surround the portal vein, hepatic artery, and bile duct, give rise to a particular ultrasound pattern: the "rosebud pattern."

Work in progress CAVUS: transcaval ultrasonography of abdominal organs. Preliminary results.

Endoluminal sonography using tiny transducers (20 MHz) has found wide application in various fields of investigation. We have applied the same technology to the assessment of abdominal organs using the transcaval route (CAVUS). Normal vessels and both normal and dilated bile ducts were displayed. Although the procedure is simple and safe, and the images produced are excellent, to be useful clinically, microtransducers (6 or 7 MHz) will have to be developed. This technique holds much promise, and further miniaturization will allow greatly expanded use of endoluminal approaches.

The butterfly sign: an indicator of fluid within both the greater peritoneal cavity and the lesser omental bursa.

Fluid accumulations present in the lesser omental bursa and the greater peritoneal cavity simultaneously outline a pattern resembling a butterfly. This "butterfly sign" can contribute to a more accurate diagnosis in evaluation of acute pancreatic processes and, more generally, acute abdominal syndromes.

Sonographic study of the juxtarenal retroperitoneal compartments.

Computed tomographic scanning has brought analysis of the different retroperitoneal compartments and fascias into routine radiologic diagnosis. Ultrasound has generally been thought to be incapable of revealing the details of these anatomic structures unless they are enhanced by pathologic changes, such as the presence of fluid collections. The authors show that sonograms can reveal the anatomic features of the juxtarenal compartments in patients with pathologic conditions as well as in many normal subjects.

Cambio del isotipo en la respuesta a antígenos T independientes por co-inoculación con antígenos T dependientes / Isotype switch in the response against T independent antigens by co-inoculation with T dependent antigens

Un paradigma clásico de la inmulogía plantea que para que ocurra cambio de isotipo en los anticuerpos es condición sine qua non la presentación del antígeno a un linfócito T colaborador por parte de una célula presentadora de antígenos. En el presente trabajo se diseñó un modelo animal, ratones BALB/c, de respuesta inmune frente a dos antígenos típicos. Se utilizo dextrán como antígeno T independiente (AgTI) y seroalbúmina bovina (SAB) como antígeno T dependiente (AgTD), y se estúdio la respuesta, analizando los isotipos de los anticuerpos específicos producidos. Los resultados obtenidos muestran que la respuesta a dextrán en presencia de SAB ocurre con cambio de isotipo (swith), essencialmente de IgM a IgG. Estos experimentos sugieren que la SAB genera un entorno bioquímico inductor de cambio de isotipo tanto en supropia via de procesamiento como en del dextrán. Los resultados señalan que la asociación exclusiva de los AgTDs con las respuestas em las que ocurre cambio de isotipo es incorrecta. Considerando el modelo propuesto resulta poco probable encontrar in vivo y en forma espontânea casos en los que los AgTIs ingreses al organismo aislados; en cambio, es mucho más probable que el ingreso ocurra conjuntamente con AgTDs, y en consecuencia ocurra cambio de isotipo.