Tomografía computada de doble energía para la detección de lesiones focales hepáticas / Dual-energy computed tomography for the detection of focal liver lesions

Objetivo. Explorar cualitativamente y cuantitativamente el estudio espectral de las lesiones focales hepáticas, comparándolo con la valoración policromática habitual de la tomografía de energía simple. Método. El presente estudio prospectivo incluyó 50 pacientes remitidos para la realización de tomografía computada multidetector abdominal con contraste intravenoso, que tuvieran al menos una lesión focal hepática. La fase portal fue adquirida con energía dual. Se realizaron mediciones densitométricas de las lesiones y del parénquima hepático circundante, tanto en la adquisición policromática basal como en las posteriores reconstrucciones monocromáticas a 40, 70 y 140 keV. Se trazaron las curvas espectrales y se calcularon los índices de doble energía y la relación contraste-ruido. Por último, se hizo una valoración subjetiva de la calidad de las imágenes y la detectabilidad lesional. Resultados. Las diferencias densitométricas entre los distintos tipos de lesiones (avasculares y vascularizadas) y el hígado fueron mayores a bajos niveles energéticos (a la izquierda de la curva espectral) que en la evaluación policromática. En la valoración subjetiva, el nivel energético de 40keV presentó una mayor detectabilidad lesional. Conclusiones. El estudio espectral monocromático mediante tomografía computada de energía dual provee una mayor detectabilidad lesional a 40keV en relación a la que se dispone con la valoración policromática habitual (AU)

Objective. To qualitatively and quantitatively explore the spectral study of focal liver lesions, comparing it with the usual polychromatic assessment with single-energy computed tomography. Material and methods. We prospectively studied 50 patients with at least one focal liver lesion who were referred for abdominal multidetector computed tomography with intravenous contrast material. The portal phase was acquired with dual energy sources. The density of the lesions and of the surrounding liver parenchyma was measured both in the baseline polychromatic acquisition and in the posterior monochromatic reconstructions at 40 keV, 70 keV, and 140 keV. Spectral curves were traced and the dual-energy indices and contrast-to-noise ratio were calculated. Lastly, the quality of the images and the detectability of the lesions were assessed qualitatively. Results. Densitometric differences between the different types of lesions (avascular and vascularized) and the liver were greater at low energy levels (left side of the spectral curve) than in the polychromatic evaluation. In the subjective assessment, the 40keV energy level had the greatest lesion detectability. Conclusions. Monochromatic spectral study with dual-energy computed tomography provides better lesion detectability at 40keV compared to that provided by the ordinary polychromatic evaluation (AU)

Dual-energy computed tomography for the detection of focal liver lesions. / Tomografía computada de doble energía para la detección de lesiones focales hepáticas.

OBJECTIVE: To qualitatively and quantitatively explore the spectral study of focal liver lesions, comparing it with the usual polychromatic assessment with single-energy computed tomography. MATERIAL AND METHODS: We prospectively studied 50 patients with at least one focal liver lesion who were referred for abdominal multidetector computed tomography with intravenous contrast material. The portal phase was acquired with dual energy sources. The density of the lesions and of the surrounding liver parenchyma was measured both in the baseline polychromatic acquisition and in the posterior monochromatic reconstructions at 40 keV, 70 keV, and 140 keV. Spectral curves were traced and the dual-energy indices and contrast-to-noise ratio were calculated. Lastly, the quality of the images and the detectability of the lesions were assessed qualitatively. RESULTS: Densitometric differences between the different types of lesions (avascular and vascularized) and the liver were greater at low energy levels (left side of the spectral curve) than in the polychromatic evaluation. In the subjective assessment, the 40keV energy level had the greatest lesion detectability. CONCLUSIONS: Monochromatic spectral study with dual-energy computed tomography provides better lesion detectability at 40keV compared to that provided by the ordinary polychromatic evaluation.

Vancomycin-sensitized photooxidation in the presence of the natural pigment vitamin B2: Interaction with excited states and photogenerated ROS.

Sensitized photooxidation processes in the presence of natural pigments may provide an alternative to antibiotics degradation since these compounds are transparent to natural light irradiation, therefore, they can be degraded by the action of photosensitizers which absorb light and produce highly reactive species, especially those derived from molecular oxygen (ROS). Most antibiotics used currently belong to a group of pharmaceutical substances that have been considered a new type of contaminants due to their persistence and bioaccumulation in the environment. OBJECTIVE: In this context, we decided to investigate the kinetic and mechanistic aspects of Vancomycin (Vanco) photosensitized degradation in the presence of the natural pigment Riboflavin (Vitamin B2, Rf) and the artificial dye Rose Bengal (RB) for comparative purposes. METHODS: The study have been done by using Stationary photolysis, Laser flash photolysis, Time-resolved phosphorence detection of O2(1Δg) experiments and Bactericidal activity evaluation. The experiments were carried out in aqueous solution at different pH values in order to establish relationships between the structure of the compound and its susceptibility to ROS-mediated photooxidation. RESULTS: Experimental evidence indicates that in the presence of Rf there is considerable contribution of the radical-mediated mechanism, while in the presence of RB the photooxidation process occurs exclusively through O2(1Δg) and the reactivity to this excited species increases with increasing pH of the environment. DISCUSSION: The results obtained, have been shown that Rf can raise the photodegradation of Vanco by both the radical pathway and the O2(1Δg) mediated. Furthermore, the antibiotic is able to interact with the excited electronic states of Rf as well as O2(1Δg) generated by energy transfer between the excited triplet state of the photosensitizer and the oxygen ground state. The predominant mechanism for photodegradation of Vanco in the presence of the Rf is the radical via because of the considerable interaction with the excited triplet state of the photosensitizer demonstrated by laser flash photolysis experiments. Microbiological test on Staphylococcus aureus ATCC25923 showed that the bactericidal activity of the antibiotic on the strain studied was affected by the sensitized photodegradation process, suggesting that photoproducts generated eventually do not retain the bactericidal properties of the original antibiotic.

Enzalutamide as monotherapy for advanced prostate cancer: why not? / Enzalutamida como monoterapia para cáncer de próstata avanzado: ¿por qué no?

OBJECTIVES: Prostate cancer (PCa) is an androgen-dependent disease. In some cases, the tumor progresses despite castration levels of serum testosterone, turning into the lethal phenotype of castration-resistant prostate cancer (CRPC), still driven by androgens and requiring the androgen receptor as a driver and responsible for progression. Enzalutamide, an androgen receptor inhibitor, is indicated for the treatment of metastatic CRPC, asymptomatic or mildly symptomatic, after failure of androgen deprivation. In both clinical trials that led to its approval, Enzalutamide was administered with an LHRH analog, setting the "standard of care" for its use. In this article we evaluate the available evidence and theory on the use of Enzalutamide as monotherapy. METHODS: Androgen deprivation well-known adverse events, together with the fact that its clinical benefit is moderate and the evidence strength is weak, and the direct negative impact on the common chronic conditions affecting this age-group led to investigation of Enzalutamide without LHRH analogs. RESULTS: There are clinical trials on Enzalutamide monotherapy for hormone-sensitive prostate cancer with favourable outcomes, and there are also two ongoing studies in different advanced PCa scenarios, the PROSPER and EMBARK trials. It would be up to now a safe alternative, with less toxicity and lower costs. CONCLUSION: It is mandatory to validate these early results on the use on Enzalutamide monotherapy for advanced prostate cancer, hormone-sensitive or castration resistant, metastatic or not, but in the meantime, we wonder, why not?

Kinetic and mechanistic aspects of sensitized photodegradation of ß-lactam antibiotics: microbiological implications.

Amoxicillin (Amx) and cephalexin (Cfx) are ß-lactam antibiotics widely used in human and veterinary medicine. Two points of interest surrounding these molecules are the photodegradation of the molecules and their microbiological implications, as well as the persistence and bioaccumulation in the environment which may cause resistance to bacterial strains. The kinetic and mechanistic aspects of the photosensitized degradation of Amx and Cfx have been studied in water at pH 7.4 and 10 by stationary and time-resolved methods. Kinetic evidence indicates that the Rose Bengal-sensitized photooxidation of Amx at pH 7.4 proceeds via O(2)((1)Δ(g)) and O(2•-) mechanisms while at pH 10 the degradation path occurs, principally, via O(2)((1)Δ(g)). For Cfx, this process is attributed to O(2)((1)Δ(g)) and O(2•-). Photoproducts, which arise from the addition of oxygen atoms and subsequent oxidation of the groups -CH(3) to -COOH, were detected. For both antibiotics the bacteriostatic activity decreases in parallel to their photodegradation. The results of this study could potentially help scientists to better understand and predict the photodegradability of these antibiotics on living organisms and in different environmental compartments.

Begomoviruses Associated with Bean Golden Mosaic Disease in Nicaragua.

Begomovirus spp. cause substantial losses in bean crops in tropical and subtropical regions of the Americas. The predominant Begomovirus sp. in Central America associated with golden mosaic symptoms in bean is Bean golden yellow mosaic virus (BGYMV). However, Calopogonium golden mosaic virus was previously found to infect bean crops in the northern region of Costa Rica. The objective of this research was to identify Begomovirus spp. that infect bean plants in different geographical regions of Nicaragua. In all, 126 samples of young bean leaves with symptoms of golden mosaic were collected from eight different regions of Nicaragua. Using DNA hybridization with specific probes, 120 samples tested positive for BGYMV, 14 samples tested positive for Squash yellow mild mottle virus, and 7 samples tested positive for Calopogonium golden mosaic virus. Sequence analysis of polymerase chain reaction-amplified products from three samples (MA-9 Managua, BE-8 Rivas, and SO-9 Granada) also indicated that the symptoms of golden mosaic in bean are associated with viral sequences from three different Begomovirus spp. Management of bean golden mosaic disease must take into account that BGYMV is the predominant virus (95% of the samples) and that 12% of the samples exhibited possible mixed infections or recombination events in the south and central geographical regions of Nicaragua.

Kinetics of the photosensitized oxidation of chymotrypsin in different media.

The kinetic aspects of the Perinaphthenone-sensitized photooxidation (singlet molecular oxygen [O2 ((1)Delta(g))]-mediated) of alpha-chymotrypsin (alpha-Chymo) have been studied at pH 8 and pH 11 as well in reverse micelles (RMs) of sodium 1, 4 bis (2-ethylhexyl) sulfosuccinate (AOT) in n-heptane. The rate constant values for both overall (k(t)) and chemical (k(r)) quenching of O2 ((1)Delta(g)) by alpha-Chymo in homogeneous media were higher at pH = 11 than at pH = 8, indicating that the OH-ionized tyrosine (Tyr) residues, clearly dominate the quenching process. Besides, the rate constants in water were higher than those determined in RMs, demonstrating that the organized medium protects the protein against photooxidation, probably due to a diminution in both, the accessibility towards oxidizable amino acid residues and the polarity inside the aggregate, as compared to water. The protection effect of alpha-Chymo against the attack by the oxidative species O2 ((1)Delta(g)) in RMs of AOT seems to be due to the increase of protein stability by the encapsulation within the micellar structure. The effect of both, surfactant concentration and variation of the ratio ([H2O]/[AOT]) = W on the reactive rate constant was also investigated. The process does not depend significantly on micelles concentration while the k(r) values increase as W increases. Furthermore, at W = 30, the highest W studied, k(r) tends to the value obtained in aqueous medium.

Human defensin 5 expression in intestinal metaplasia of the upper gastrointestinal tract.

BACKGROUND: Upper gastrointestinal tract intestinal metaplasia (IM) is termed Barrett's oesophagus (BO) or gastric intestinal metaplasia (GIM), depending on its location. BO and GIM are associated with chemical exposure resulting from gastro-oesophageal reflux and chronic Helicobacter pylori infection, respectively. Paneth cells (PCs), characterised by cytoplasmic eosinophilic granules, are found in a subset of IM at these sites, but histology may not accurately detect them. AIM: To determine human defensin 5 (HD5; an antimicrobial peptide produced by PCs) expression in BO and GIM, and to investigate its association with H pylori infection. METHODS: Endoscopic biopsies from 33 patients with BO and 51 with GIM, and control tissues, were examined by routine histology and for H pylori infection and HD5 mRNA and protein expression. RESULTS: In normal tissues, HD5 expression was specific for PCs in the small intestine. Five patients with BE and 42 with GIM expressed HD5, but few HD5 expressing cells in IM had the characteristic histological features of PCs. Most HD5 positive specimens were H pylori infected and most HD5 negative specimens were not infected. CONCLUSIONS: HD5 immunohistochemistry was often positive in IM when PCs were absent by conventional histology. Thus, HD5 immunohistochemistry may be superior to histology for identifying metaplastic PCs and distinguishing GIM from BO. The higher frequency of HD5 expression in GIM than in BO is associated with a higher frequency of H pylori infection, suggesting that in IM PCs may form part of the mucosal antibacterial response.

A single, double lumen high-flow catheter for patients undergoing peripheral blood stem cell transplantation. Experience at the National Cancer Institute in Mexico.

Peripheral blood stem cell transplantation (PBSCT) requires a high-flow catheter for adequate cell collection by apheresis and long i.v. support, this is usually achieved by multiple catheters. We analyzed our experience with Mahurkar or Permacath for apheresis and long-term i.v. support in PBSCT, cared for exclusively by an i.v. therapy team. Fifty-six catheters were used in 53 patients that completed PBSCT (28 Permacath and 28 Mahurkar). In 10 patients (19%) the same catheter was used for multiple PBSCT. The average stay was 58.4 days (7-219), Permacath 76.8 days (14-219) and Mahurkar 42 days (7-106). The incidence of infectious complications was 2.2 x 1000 catheter-days (1.7 Permacath and 3.0 Mahurkar); during neutropenia it was 3.7 x 1000 cathether-days. The incidence of thrombosis was 0.9 x 1000 catheter-days. There was a total of seven infectious episodes (12.7%). Five (9%) were local and two were (3.6%) bacteremias. The microorganism most commonly isolated was Staphylococcus sp. (57%). Four catheters (7.1%) were removed because of complications: one thrombosis and three infections. Both catheters have proven useful and safe for long-lasting vascular access in patients undergoing PBSCT. No statistical difference was found in infectious and non-infectious complications between either catheters.

Aprotinin effects related to oxidative stress in cardiosurgery with mechanical cardiorespiratory support (CMCS).

There is evidence to support a relationship between oxidative stress and protease release in "ischemia-reperfusion damage." We have proposed that aprotinin may exert an antioxidant effect. A double blind clinical trial was performed with a control (G-1) and treated (G-2) groups, both submitted to CMCS. Blood samples were taken 5 times. Biochemical indicators were measured spectrophotometrically. Aprotinin was supplied by Bayer. Malonildialdehyde levels were greater in G-1 (7.2 +/- 3.6 nmoles/ml) than in G-2 (4 +/- 1.65) at the time of reperfusion. Phospholipase A2 exhibited a tendency of higher activity in G-1 than in G-2. Uric acid levels were higher in G-2 (431 +/- 274 mumoles/1) than in G-1 (224 +/- 188) at 5 minutes after aortic clamping, and catalase activity was greater in G-2 (294 +/- 55 KU/1) than in G-1 (118 +/- 47) at time of reperfusion. Low cardiac output was 10% in G-2 and 30% in G-1. Arrythmias appeared in 30% of G-2 and in 60% of G-1. These results suggest an antioxidant effect of aprotinin under ischemia-reperfusion conditions.

[Cytogenetic findings in chronic myelocytic leukemia and their prognostic correlation in patients of the National Institute of Cancer of Mexico]. / Hallazgos citogenéticos en leucemia mielocítica crónica y su correlación pronóstica en pacientes del Instituto Nacional de Cancerología de México.

This study describes the cytogenetic alterations in patients with chronic myelogenous leukemia (CML) seen at the Instituto Nacional de Cancerologia (INCAN), Mexico City, whether they have been treated previously or not. It correlates these findings with the prognosis. We studied 31 patients seen during June 1987 and June 1990. Philadelphia (Ph+) chromosome was present in 61% of all specimens. In 10 cases it was the only anomaly, resulting in a survival greater than 40 months. Aneuploidies were seen in 50% of patients with previous treatment and in 31.5% of those without treatment. Patients with numerous abnormalities and double Ph+ (with or without Ph+ chromosome) had a mean survival of 32 months. The worst prognosis was seen in the a cases with no growth, with a mean survival of 19 months. This study suggests that the prognosis of patients with CML correlates with the cytogenetic anomalies whether patients have been treated previously or not. It also seems that the group of patients whose cytogenetic study does not grow or cannot be evaluated upon direct exam have a worse prognosis which may be secondary to intrinsic defects of the neoplastic cells that do not grow in vitro, resulting in a more aggressive disease in vivo.

Radiotherapy compared to chemotherapy as initial treatment of angiocentric centrofacial lymphoma (polymorphic reticulosis).

Polymorphic reticulosis has recently been characterized as an angiocentric lymphoproliferative disorder of the peripheral T-lymphocytes. However, its treatment is still a matter of controversy. In order to study efficacy and toxicity of the primary treatment, we reviewed clinical features and therapeutic results in 29 patients seen at the Instituto Nacional de Cancerologia de Mexico. Nineteen patients received primary local irradiation and 10 patients primary combination chemotherapy. In the radiotherapy group, 14 (74%) patients achieved complete response, but only 4 (40%) did so in the primary chemotherapy group. Five patients in the latter group died of treatment-related complications. The 5-year actuarial survival rate was 70% in the irradiation group, while the 1-year survival rate was only 15% in the chemotherapy group. These data strongly suggest that, in polymorphic reticulosis, initial chemotherapy may be very toxic.

Primary B cell lymphoma of the rectum in a patient coinfected with HIV-1 and HTLV-I.

This report describes a clinical case of a large cell, immunoblastic plasmacytoid malignant B-cell lymphoma of the rectum in an AIDS patient coinfected with HTLV-I. The malignant cells showed clonal genetic rearrangement of the HC (JH) and LCK genes. Infection by EBV was demonstrated serologically and with slot blots using genomic DNA of the cancer cells. Southern blot analysis with DNA extracted from the lymphoma cells were negative for HTLV-I. The patient received seven cycles of VACO-B which induced complete but transient clinical remission of the tumor. The final outcome of the patient is unknown.

Constitutional translocation (8;13) in a patient with non-Hodgkin's lymphoma.

We report a case of non-Hodgkin's lymphoma in a 16-year-old male, whose peripheral white blood cells have a t(8;13)(q24;q14). There are no previous reports that describe this association. Although the tumor cells were not studied, we discuss the possible link between this finding and the development of the malignant lymphoma.

[Seroprevalence of viral markers of hepatitis B among health professionals. Multicenter study in Mexico]. / Seroprevalencia de marcadores virales de hepatitis B en profesionales de la salud. Estudio multicéntrico en México.

To determine the prevalence of serological markers for hepatitis B infection among health care workers (HCW) in Mexico we surveyed 1072 volunteers from 26 hospitals in 12 states, from which only 1017 fulfilled the inclusion criteria: 82 patients (8.1%) were excluded because of lipemic and/or hemolyzed serum, leaving 935 persons in the study. The study population consisted of physicians, nurses, laboratory chemists, health laboratory technicians and odontologists. All of them had been working in their respective fields and in contact with biological materials for at least 12 months. None of them had been vaccinated for hepatitis B. We determined the presence of HBsAg and anti-HBs by the ELISA method. The participants' mean age was 31.4 years (range: 18-72) and their mean working time was 7.8 years. 615 were female and 320 male. The HBsAg was positive in 11 (1.2%) and the anti-HBs in 91 cases (9.7%). These results suggest that HCW in Mexico have a greater relative risk of becoming infected with the HB virus than the general population. Relative risks were particularly higher for the health laboratory technicians and the physicians. These results confirm that biohazard measures must be reinforced and that the application of HB virus vaccine could be recommended for health care workers.

Acute leukemia during pregnancy: the Toronto Leukemia Study Group experience with long-term follow-up of children exposed in utero to chemotherapeutic agents.

The incidence of acute leukemia in pregnancy is low and even referral centers have limited experience. Although the short-term risks for children exposed in utero to cytotoxic agents are predictable, there is no information on long-term complications. We report here our experience in the treatment of seven cases of acute leukemia diagnosed during pregnancy, and a literature review of 51 cases published since 1975. Fifty-three patients received chemotherapy during their pregnancies. Forty-nine of the 58 cases resulted in the birth of 50 live infants. Twenty-eight infants were born prematurely, and four had low birth-weights for their gestational age. Thirty-three percent of the newborns exposed to chemotherapy in the last month of pregnancy were cytopenic at birth, but other perinatal complications were not increased. Only one child (present series) had obvious congenital malformations, and this same infant later developed a neuroblastoma arising in the adrenal gland and a papillary carcinoma of the thyroid. Follow-up data are not provided in most previously reported cases, but long-term follow-up of our cases from 1 to 17 years has shown normal growth and development and no further malignancies. A central registry is strongly advised in order to document the long-term complications arising in children exposed to chemotherapy in utero.

Acute leukemia occurring 19 years after treatment of acute lymphoblastic leukemia.

A 22-year-old woman presented with acute lymphoblastic leukemia (ALL) during pregnancy. She had been successfully treated for ALL at the age of 3 years and had received maintenance treatment for 11 years. Complete remission of 3 years or more is an important factor for long-term survival and potential cure. Relapses may occur in the first 5 years after maintenance is discontinued. Later relapses are distinctly unusual. We have found six more cases of ALL occurring long after the initial remission in the English literature. It is unclear whether late relapse represents true relapse or a second leukemia. Life-long follow-up of children with ALL may be necessary.