5-Fluorouracil drug delivery system based on bacterial nanocellulose for colorectal cancer treatment: Mathematical and in vitro evaluation

Colorectal cancer (CRC) is the third most common worldwide. Its treatment includes adjuvant chemotherapy with 5-fluorouracil (5FU) administered intravenously. 5FU is an antineoplastic drug of the fluoropyrimidines group, widely used in the treatment of solid tumors, mainly CRC. Nevertheless, it causes several adverse effects and poor effectiveness due to its short half-life. This work aimed to employ bacterial nanocellulose (BNC) as an encapsulation material for the oral administration of 5FU. First, the adsorption phenomena were analyzed by isotherms, thermodynamic parameters, and kinetic models. Then, encapsulation was carried out using spray-drying, and encapsulated 5FU desorption profiles were assessed in simulated fluids. The biological behavior was evaluated on colon cancer SW480 and SW620 cell lines. As result, it was found that at 25 °C a monolayer of 5FU was formed and the process showed to be the most spontaneous one. In the characterization of the nanocapsules, important changes were detected by the presence of 5FU. The delivery in the colon corresponded to a controlled release behavior. The in vitro assay indicated an improvement in the toxicity effect of the drug and its mechanism of action. Accordingly, BNC is a promising biomaterial for the development of a colon drug delivery platform of 5FU.

Artificial Intelligence for Modeling Complex Systems: Taming the Complexity of Expert Models to Improve Decision Making

Major societal and environmental challenges involve complex systems that have diverse multi-scale interacting processes. Consider, for example, how droughts and water reserves affect crop production and how agriculture and industrial needs affect water quality and availability. Preventive measures, such as delaying planting dates and adopting new agricultural practices in response to changing weather patterns, can reduce the damage caused by natural processes. Understanding how these natural and human processes affect one another allows forecasting the effects of undesirable situations and study interventions to take preventive measures. For many of these processes, there are expert models that incorporate state-of-the-art theories and knowledge to quantify a system's response to a diversity of conditions. A major challenge for efficient modeling is the diversity of modeling approaches across disciplines and the wide variety of data sources available only in formats that require complex conversions. Using expert models for particular problems requires integration of models with third-party data as well as integration of models across disciplines. Modelers face significant heterogeneity that requires resolving semantic, spatiotemporal, and execution mismatches, which are largely done by hand today and may take more than 2 years of effort.

We are developing a modeling framework that uses artificial intelligence (AI) techniques to reduce modeling effort while ensuring utility for decision making. Our work to date makes several innovative contributions: (1) an intelligent user interface that guides analysts to frame their modeling problem and assists them by suggesting relevant choices and automating steps along the way; (2) semantic metadata for models, including their modeling variables and constraints, that ensures model relevance and proper use for a given decision-making problem; and (3) semantic representations of datasets in terms of modeling variables that enable automated data selection and data transformations. This framework is implemented in the MINT (Model INTegration) framework, and currently includes data and models to analyze the interactions between natural and human systems involving climate, water availability, agricultural production, and markets. Our work to date demonstrates the utility of AI techniques to accelerate modeling to support decision-making and uncovers several challenging directions for future work.

Improved algorithm with adaptive regularization for tomographic reconstruction of gas distributions using DOAS measurements

Differential optical absorption spectroscopy (DOAS) is notably well suited for the retrieval of UV-absorbing trace gases present in the atmosphere. We combine multi-axis DOAS observations to perform a tomographic reconstruction of the distribution of gases emitted from different sources. We use a new algorithm based on a regularized minimization approach embedding key physical aspects of the solution to constrain the inversion. In this work, we take into account that the spatial sampling of the plume being scanned by the instruments is not homogeneous. Therefore, we introduce an adaptive approach with a locally tuned regularization weight according to the uncertainty levels introduced by the sampling scheme. We tested our approach on reconstructions of simulated gas distributions and different configurations applicable to multi-axis DOAS. Finally, our approach is applied to experimental data for the retrieval of the distribution of ${\rm NO}_2$NO₂ within a plume cross section emitted from a group of stacks.

Ex Vivo and In Vivo Biocompatibility Assessment (Blood and Tissue) of Three-Dimensional Bacterial Nanocellulose Biomaterials for Soft Tissue Implants

Bacterial nanocellulose (BNC) is a promising biomedical material. However, the haemocompatibility (haemolysis and thrombogenicity) and acute and sub-chronic immune responses to three-dimensional (3D) BNC biomaterials have not been evaluated. Accordingly, this manuscript focused on the effect of 3D microporosity on BNC haemocompatibility and a comparison with 2D BNC architecture, followed by the evaluation of the immune response to 3D BNC. Blood ex vivo studies indicated that compared with other 2D and 3D BNC architectures, never-dried 2D BNC presented antihemolytic and antithrombogenic effects. Nevertheless, in vivo studies indicated that 3D BNC did not interfere with wound haemostasis and elicited a mild acute inflammatory response, not a foreign body or chronic inflammatory response. Moreover, compared with the polyethylene controls, the implant design with micropores ca. 60 µm in diameter showed a high level of collagen, neovascularization and low fibrosis. Cell/tissue infiltration increased to 91% after 12 weeks and was characterized by fibroblastic, capillary and extracellular matrix infiltration. Accordingly, 3D BNC biomaterials can be considered a potential implantable biomaterial for soft tissue augmentation or replacement.

Novel surface modification of three-dimensional bacterial nanocellulose with cell-derived adhesion proteins for soft tissue engineering

Bacterial nanocellulose (BNC) is a natural polymer composed of glucose units with an important application as a two and three-dimensional scaffold for tissue engineering. However, as a polysaccharide, BNC does not have the biological signals of protein biomaterials. Therefore, this paper aims to develop a novel methodology to biomimic soft extracellular matrix (ECM) chemistry on to 3D BNC using the bioengineering of fibroblasts (the cells responsible for producing and regenerating the ECM) to immobilise adhesion proteins such as collagen and fibronectin. Modified 3D BNC (Mod-BNC) biomaterials were morphologically, thermally, and chemically characterised, and furthermore, the cell response was analysed by adhesion studies using atomic force microscopy (AFM), XTT assay, and confocal microscopy. Cell-derived proteins were deposited on the BNC nanoribbon network to modify its surface. The contact angle was increased from 40° to 60°, reducing the wettability of the biomaterial, and during thermogravimetry, the proteins in Mod-BNC exhibited an enhanced thermal stability because of the interactions between themselves and BNC. Chemical and immunocytochemistry analyses confirmed the presence of collagen type I and fibronectin on 3D BNC. These proteins activate integrin adhesion pathways that generate stronger cell adhesions. AFM experiments showed higher forces and energies on modified biomaterials, and moreover, the cells that adhered on to Mod-BNC exhibited higher mitochondrial activity and higher cell populations per cubic millimetre than non-modified surfaces (NMod-BNC). Accordingly, it was established that this novel methodology is robust and able to biomimic the chemical surface of soft ECM and immobilise cell-derived adhesion proteins from fibroblast; moreover, the Mod-BNC exhibited better cell response than NMod-BNC because of the biological signals in 3D BNC.

Dose-dense regimen of temozolomide given every other week in patients with primary central nervous system tumors

BACKGROUND

Temozolomide has shown activity and limited toxicity in patients with primary brain tumors at doses of 150-200 mg/m(2)/day on days 1-5 every 4 weeks. In this study, a new alternative dose-dense regimen of temozolomide was explored in patients with recurrent brain tumors.

PATIENTS AND METHODS

In this study, we evaluated the safety, dose-limiting toxicity, maximum tolerated dose, recommended dose and activity of temozolomide given on days 1-3 and 14-16 every 28 days (one cycle). The starting daily dose was 200 mg/m(2) in a group of at least six patients, with subsequent increments of 50 mg/m(2) in groups of at least 12 patients until unacceptable toxicity was reached. Oral ondansetron (8 mg) was given 1 h prior to temozolomide administration. McDonald's criteria were used to evaluate antitumor activity.

RESULTS

Seventy patients with brain tumors entered this study. The median number of prior chemotherapy treatments was two (range 1-3). Patients were assigned to one of four groups to receive temozolomide at daily doses of 200 (seven patients), 250 (13 patients), 300 (38 patients) and 350 mg/m(2)/day (12 patients). The absence of dose-limiting toxicity at cycle 1 led us to establish dose recommendations based on toxicity after repeated cycles. A total of 23, 72, 192 and 83 cycles were given at daily doses of 200, 250, 300 and 350 mg/m(2), respectively. Grade 3-4 thrombocytopenia was observed in 0/7, 1/13, 5/38 and 4/12 patients treated at doses of 200, 250, 300 and 350 mg/m(2)/day, respectively. Grade 3-4 neutropenia was observed in 1/7, 0/13, 3/38 and 4/12 patients treated with 200, 250, 300 and 350 mg/m(2)/day temozolomide, respectively. At a dose of 350 mg/m(2), sustained grade 2-3 thrombocytopenia did not allow treatment to be resumed at day 14 in >40% of patients, and this dose was considered to be the maximum tolerated dose. Thus, a dose of 300 mg/m(2)/day that was associated with <20% treatment delay due to sustained hematological toxicity was considered as the recommended dose. Objective responses were reported in 13 patients.

CONCLUSIONS

Temozolomide can be given safely using a dose-dense regimen of 300 mg/m(2)/day for 3 consecutive days every 2 weeks in patients with recurrent brain tumors.

Phosphatidylcholine-specific phospholipase C and sphingomyelinase activities in bacteria of the Bacillus cereus group

Bacillus anthracis is nonhemolytic, even though it is closely related to the highly hemolytic Bacillus cereus. Hemolysis by B. cereus results largely from the action of phosphatidylcholine-specific phospholipase C (PC-PLC) and sphingomyelinase (SPH), encoded by the plc and sph genes, respectively. In B. cereus, these genes are organized in an operon regulated by the global regulator PlcR. B. anthracis contains a highly similar cereolysin operon, but it is transcriptionally silent because the B. anthracis PlcR is truncated at the C terminus. Here we report the cloning, expression, purification, and enzymatic characterization of PC-PLC and SPH from B. cereus and B. anthracis. We also investigated the effects of expressing PlcR on the expression of plc and sph. In B. cereus, PlcR was found to be a positive regulator of plc but a negative regulator of sph. Replacement of the B. cereus plcR gene by its truncated orthologue from B. anthracis eliminated the activities of both PC-PLC and SPH, whereas introduction into B. anthracis of the B. cereus plcR gene with its own promoter did not activate cereolysin expression. Hemolytic activity was detected in B. anthracis strains containing the B. cereus plcR gene on a multicopy plasmid under control of the strong B. anthracis protective antigen gene promoter or in a strain carrying a multicopy plasmid containing the entire B. cereus plc-sph operon. Slight hemolysis and PC-PLC activation were found when PlcR-producing B. anthracis strains were grown under anaerobic-plus-CO(2) or especially under aerobic-plus-CO(2) conditions. Unmodified parental B. anthracis strains did not demonstrate obvious hemolysis under the same conditions.

Epidermal growth factor-based cancer vaccine for non-small-cell lung cancer therapy

BACKGROUND

The role that growth factors and their receptors play in human cancer growth and progression makes them interesting targets for novel treatment modalities. Our approach consisted of active immunotherapy with the epidermal growth factor (EGF). Two pilot clinical trials were conducted to examine the safety and immunogenicity of a five-dose immunization protocol and to compare different adjuvants and treatment designs.

PATIENTS AND METHODS

Forty patients with advanced non-small-cell lung cancer were enrolled in both trials. They were randomized to be treated with aluminum hydroxide or montanide ISA 51 as adjuvants in the EGF vaccine preparation. The use of cyclophosphamide prevaccination treatment was evaluated in the second trial.

RESULTS

Pooled data from both trials showed that the use of montanide as adjuvant increased the percentage of good antibody responders (GAR). Cyclophosphamide prevaccination treatment did not provoke improvements in antibody response. GAR had a significant increase in survival as compared with poor antibody responders. Response duration was also related to a significant improvement in survival rates.

CONCLUSIONS

Vaccination with five doses of EGF vaccine is safe and immunogenic. Montanide ISA 51 increased the percentage of GAR. There is a direct relationship between anti-EGF antibody titers and immune response duration with survival time.

Induction of hepatitis C virus-specific cytotoxic T lymphocytes in mice by immunization with dendritic cells treated with an anthrax toxin fusion protein

As a novel and safe vaccine strategy, the anthrax toxin-mediated antigen delivery system composed of lethal factor (LF) fusion protein and protective antigen (PA) has been studied to prime hepatitis C virus (HCV) core-specific cytotoxic T lymphocytes (CTLs) in vivo. The core epitope fused to LF (LF-core) together with PA induces a negligible core-specific CTL response in mice, whereas core-specific CTL are effectively primed in mice by injecting dendritic cells (DCs) treated in vitro with LF-core and PA. These findings imply that LF fusion protein plus PA in combination with dendritic cells may be useful for a novel T cell vaccine against HCV infection.

Selective export of MHC class I molecules from the ER after their dissociation from TAP

It has been assumed that upon dissociation from TAP, MHC class I molecules exit the ER by nonselective bulk flow. We now show that exit must occur by association with cargo receptors. Inconsistent with exit by bulk flow, loading of MHC class I molecules with high-affinity peptides triggers dissociation from TAP but has no effect on rates of ER-to-Golgi transport. Moreover, peptide-loaded MHC class I molecules accumulate at ER exit sites from which TAP molecules are excluded. Consistent with receptor-mediated exit, ER-to-Golgi transport of MHC class I molecules is independent of their cytoplasmic tails, which themselves lack ER export motifs. In addition, we show that MHC class I molecules associate with the putative cargo receptor BAP31.

Insulin-like growth factors (IGFs) and IGF binding proteins-1, -2, and -3 in newborn serum: relationships to fetoplacental growth at term

Cord sera were obtained from term, Chilean newborns exhibiting various patterns of intrauterine growth and assayed for IGF-1, IGF-2, IGFBP-1, IGFBP-2, and IGFBP-3 by specific radioimmunoassays (RIA). Serum levels of each peptide were correlated with birth weight (BW), ponderal index (PI), and placental weight (PW). Total IGF-1 levels correlated with BW (r = 0.665, P = 0.0001). PI (r = 0.527, P = 0.004), and PW (r = 0.596, P = 0.0017). In contrast, IGF-2 failed to correlate with any growth parameter. Of the three binding proteins, IGFBP-3 exhibited the strongest relationship to each growth parameter. IGFBP-3 correlated significantly with BW (r = 0.71, P < 0.0001), PI (r = 0.782, P < 0.0001), and PW (r = 0.57, P = 0.0029). In addition IGFBP-3 levels positively correlated to IGF-1 levels (r = 0.614, P = 0.0005). By contrast, circulating IGFBP-1 and IGFBP-2 were inversely related to IGF-1 levels. All five peptides were subjected to multiple regression analysis and related to BW. Significant relationships between the predicted BW and the actual BW were observed in these infants (r = 0.802, P = 0.0006). The BWs of a cohort of unrelated North American infants were also predicted using the Chilean-derived equation and found to be significantly related to their actual BWs (r = 0.453, P = 0.0033). These relationships were strengthened by the inclusion of estimated gestational age (EGA) as an independent variable. These data point to particularly important roles for IGF-1 and IGFBP-3 in regulating fetal growth at term, and suggest that they are regulated in a coordinated manner during the latter stage of gestation. Furthermore, they suggest that IGFBPs play multiple, and potentially opposing, regulatory roles in modulating IGF action. Lastly, an integrated expression of IGF activity derived from one population significantly correlated with newborn BW in a geographically and culturally distinct population.

Limbal conjunctival autograft in a subacute alkaline corneal burn

Persistent epithelial defects are a common complication after severe alkaline corneal burns. Chemical damage to the limbal area destroys the stem cells that play a key role in corneal reepithelialization. Limbal conjunctival autograft transplantation has been proposed as a treatment to replace damaged limbal stem cells and promote epithelial healing. We report a case of a persistent epithelial defect after a severe alkaline corneal burn that was successfully treated 6 weeks after the injury with limbal autograft transplantation. Impression cytology provided valuable information for locating the healthy and damaged limbal tissue involved in the transplantation. Two weeks postoperatively the epithelial defect was completely healed, stromal vascularization was regressed, and visual acuity was improved.

Platelet-activating factor acetylhydrolase in term and preterm human milk: a preliminary report

Human milk may protect against necrotizing enterocolitis (NEC). Since platelet-activating factor (PAF) may participate in the pathophysiology of NEC, we measured PAF acetylhydrolase (PAF-AH), which metabolizes PAF, in term and preterm human milk. The activity of PAF-AH in term milk collected 2-4 days after delivery (n = 17) was 2.7 +/- 1.2 nmol x min-1 x ml-1. A higher activity was found in milk collected at similar times from mothers who delivered between 33 and 36 weeks of gestation (n = 6, 5.6 +/- 2.1 nmol x min-1 x ml-1, p < 0.01). However, milk from mothers who delivered between 26 and 32 weeks of gestation had a PAF-AH activity similar to that of term milk (n = 6, 3.0 +/- 0.7 nmol x min-1 x ml-1). With advancing lactational age, PAF-AH activity in term milk decreased, whereas the activity of this enzyme in preterm milk remained unchanged. In milk samples collected beyond 14 days after delivery from women who gave birth between 33 and 36 weeks or 26 and 32 weeks of gestation, PAF-AH activity was fivefold higher than that found in milk for women delivering at term (3.7 +/- 1.3 and 3.6 +/- 3.6 nmol x min-1 x ml-1 serum 0.7 +/- 0.4 nmol x min-1 x ml-1, respectively, p < 0.05). We speculate that the presence of PAF-AH in human milk may protect against NEC in preterm newborns.

[Colonoscopic diagnosis]

Between 1974 and 1992, we perform 3,054 colonoscopies for diagnosis in 2,770 patients, both of sexes, between the ages of 1 and 101 yr, most of them over the fifth decade of life. In 300 procedures the bowel cleansing was made with the standard method of liquid diet and enemas, and in the other 2,754 with the oral administration of saline solution 9% with optimal results. We get the sedation of patients with the intravenous administration of diazepam 10mg, or pethidine 50 mg, or midazolam 2.5 to 5 mg, and in children with ketamine and the anesthesiologist assistance. In 95% of the procedures we can see the cecum and the ileum; the diagnosis was abnormal in 52.78% of cases, normal in 45.20%, and insufficient in 02.02% specially for a bad cleansing of the bowel. In the abnormal group, the most frequent diseases we diagnose were: polyps, cancer, diverticular disease, and specific inflammatory disease of the bowel like TBC, radiation proctosigmoiditis, amebiasis, and non-specific bowel disease: "colitis", ulcerative proctocolitis, erosive colitis, and Crohn's disease. Colonoscopy is a very important method for diagnosis of colon diseases, alone or complementary of double contrast X-ray of the colon.

[Changes in the hemogram and in the laboratory parameters indicative of iron metabolism in mild viral infections]

PURPOSE

To assess the duration and intensity of the changes appearing in laboratory values related to iron utilisation during viral infection.

MATERIAL AND METHODS

With previous parental consent, 120 eutrophic infants received vaccination with attenuated measles virus or a combination of measles, mumps and rubella viruses as a model of mild viral infection. A number of laboratory tests were performed on day 0 and in two later occasions (4-21, 9-14 or 9-30); these included blood cell counts, ESR, serum iron, total iron binding capacity, transferrin saturation index, free erythrocytic protoporphyrin, serum ferritin, intra-erythrocytic ferritin, direct anti-human globulin test and C-reactive protein. The statistical analyses were done in accordance with ANOVA, Student's t test, Wilcoxon, Kruskall - Wallis, Mann-Whitney and Fisher methods.

RESULTS

A significant haemoglobin drop was seen on days 9 and 14 post-vaccination. This descent was > 10 g/L in 8.2% of the cases, and > or = 6 g/L in 19.6%. Serum iron and transferrin saturation decreased significantly, whereas mean corpuscular volume, free erythrocyte protoporphyrin and serum ferritin were significantly increased. All these but protoporphyrin recovered by day 30. Subjects with normal iron metabolism figures on day 0 and those whose thermal variations were above 38 degrees C had greater changes in the figures related to iron metabolism.

CONCLUSION

The evaluation of iron metabolism is not reliable if the patient has suffered from infection, although a mild viral one, in the three weeks prior to the study.

[Thyroid profile in normal pregnancy]

The aim of this study was to update the thyroid hormone profile in normal pregnant women with adequate iodine nutrition, to analyze the physiological changes that occur during pregnancy and to know the role that TBG and bHCG exert on these changes. One hundred six pregnant women without goiter, former thyroid diseases or positive antimicrosomal antibodies were studied. Fifty three of them were prospectively followed during the gestational period. Thirty age matched non pregnant women were studied as a control group. Serum T3t, T4t, T41, conventional and IRMA TSH, rT3, TBG, bHCG, antimicrosomal antibodies and urinary iodine content were measured. Median urinary iodine content was 18.9 ug/ml in pregnant women, discarding iodine deficiency, the main observed changes occurred between weeks 6 and 14 with significant elevations of T3t, T4t, T41, rT3, TBG and bHCG and TSH decrease. There was a positive correlation between TBG and T3t and T4t indicating a causal relationship. There was a negative correlation between T41 and TSH and between TSH and bHCG and a positive correlation between T41 and bHCG, suggesting a thyroid stimulator effect of bHCG which would raise T41 and thus inhibit TSH secretion.

[Treatment of hyperthyroidism during pregnancy: experience with 19 cases]

Untreated hyperthyroidism in pregnant women is associated with a high incidence of maternal and fetal complications. Thus, its treatment is mandatory, ideally using PTU because it has lesser transplacental passage. From 1987 and 1991 we have attended 19 hyperthyroid pregnant women. Of these, 18 had diffuse and 1 nodular goiter and in 10, thyrotoxicosis preceded pregnancy. PTU was used in 17 women (7 received it along the whole pregnancy), five had to be operated due to poor response, one received propranolol and one patient was not treated due to lack of attendance. Cesarean section was performed in 12 women, 5 had vaginal delivery, one had a miscarriage at the 20th week of pregnancy due to a neurological malformation and one patient was lost from control before delivery. The newborn of the untreated woman had a neonatal thyrotoxicosis and the resting 16 did not show evidence of thyroid disfunction. Newborns from mothers receiving PTU until delivery had significantly lower rT3 levels and non significant changes in T4 and T3. At the end of the observation period, 8 patients were euthyroid, 3 hypothyroid (2 after 131-l and 1 after surgery), 4 continued on PTU and 4 were lost from control. It is concluded that the outcome of pregnancy may be uneventful in hyperthyroid women provided that there is a close and adequate follow up.

[Acquirement of the Spanish vocabulary among rural and urban students of the 9th region]

In order to test the assumption that rural children from the Araucanía region at southern Chile start school with significant handicaps in the acquirement of the spanish vocabulary when compared with their urban peers, the Peabody Picture Vocabulary Test (PPVT, spanish version) was used to compare a first group including all those children attending third grade at a public school from a low socio economic level neighborhood of the city of Temuco, Chile (n = 44, age average 9.01 years, s = 0.51) against a second group including all those children attending the same grade at three public schools from the rural areas surrounding the same city (n = 37, age average 9.07 years, s = 0.52). Previously, 19 children aged 3 to 5 years were tested both with the PPVT and with the chilean instrument for the measurement of development at the age group (TEPSI). Both scores show a positive correlation (r = 0.64, p = 0.05). Average scores for the PPVT among rural children were lower than among urban children (64.07, s = 11.36 against 103.05, s = 10.99, p = less than 0.01). In a second stage, 39 children attending 7th grade at the urban school (age average 13.61 years, s = 0.64) and 27 children of the same grade from the rural schools (age average 13.69 years, s = 0.69) were tested with the same instrument.(ABSTRACT TRUNCATED AT 250 WORDS)

Anemia of a mild viral infection: the measles vaccine as a model

To define the hematologic changes during a mild viral infection, 93 infants were immunized with live attenuated measles virus and studied prospectively at 0, 4, 9, 14, 21, and 30 days. Hemoglobin concentration decreased significantly by days 9 and 14. The decrease was greater than 1.0 g/dL in 8.6% and greater than 0.6 in 24.3% of the infants. Of the nonanemic infants, 22% became anemic. Serum iron and percentage saturation of transferrin decreased, whereas serum ferritin increased significantly. Mean cell volume, iron-binding capacity, protoporphyrin, and haptoglobin did not show changes. Reticulocyte index and erythropoietin increased significantly at 30 days. Leukocyte counts, Zetacrit, and C-reactive protein did not help to predict the hemoglobin decrease. These results suggest that a mild viral infection in infants induces a significant decrease in hemoglobin that may persist for 14 to 30 days and may be difficult to distinguish from iron deficiency.

[Ultrasonics in the diagnosis of choledocholithiasis]

The value of ultrasound in the diagnosis of choledocholithiasis is controversial, sensitivity figures ranging from 22 to 75%. We correlated the ultrasound study with operative findings in 38 patients. A diagnosis of common bile duct stone was made upon finding an echogenic image with or without acoustic shadow in the common bile duct; no attention was paid to the dilatation of the biliary tree. The sensitivity was 68% and the positive predictive value was 85%. Therefore, our results approach the highest reported figures for the value of this diagnostic technique.

[Radiologic correlation and endoscopy of the lesions of the colon]

Fiber colonoscopy permitted us to elucidate radiological suspicions of lesions of the colon established after repeated studies. It served to complement the radiological findings and to detect previously undiagnosed lesions and even to avoid possibly unnecessary surgical explorations when it negated the radiological diagnosis of malignant lesion. In this series, in which there were insufficient studies, no complications were registered.

Permanent hypertension after renal homotransplantation in man

1. In forty-one patients who underwent renal homotransplantation the following measurements were made: (a) blood flow and its distribution in the transplanted kidney as measured by the 85-Kr washout method; (b) renin release in the renal vein of the transplant; (c) arteriovenous difference in plasma renin activity (PRA) of the recipient's remaining left kidney. 2. Eleven transplanted patients were normotensive. Renal haemodynamic data were comparable with those obtained in potential kidney donors. 3. Three hypertensive patients had chronic rejection. The mean renal blood flow and the percentage flow in the first component of the washout curve were reduced. Renin release from the transplant, however, was normal. 4. Ten hypertensive patients had transplant artery stenosis. In eight of them renin release from the grafts as well as peripheral PRA were within normal range. This result is similar to experimental data obtained in Goldblatt renovascular hypertension. The two patients with the tightest artery stenosis had an elevated renin release from the transplant. 5. Thirteen hypertensive patients had elevated arteriovenous difference in PRA of the recipient's own left kidney. Peripheral PRA was significantly higher than in normotensive patients. Left nephrectomy relieved hypertension in ten of them; three have not so far undergone nephrectomy. 6. In four other cases hypertension was also relieved by removal of the patient's own kidney; however, the arteriovenous difference in PRA of that kidney fell within normal range.