Inhibition of 3-Hydroxy-3-Methylglutaryl–Coenzyme A Reductase and Application of Statins as a Novel Effective Therapeutic Approach against Acanthamoeba Infections

Acanthamoeba is an opportunistic pathogen in humans, whose infections most commonly manifest as Acanthamoeba keratitis or, more rarely, granulomatous amoebic encephalitis. Although there are many therapeutic options for the treatment of Acanthamoeba, they are generally lengthy and/or have limited efficacy. Therefore, there is a requirement for the identification, validation, and development of novel therapeutic targets against these pathogens. Recently, RNA interference (RNAi) has been widely used for these validation purposes and has proven to be a powerful tool for Acanthamoeba therapeutics. Ergosterol is one of the major sterols in the membrane of Acanthamoeba. 3-Hydroxy-3-methylglutaryl–coenzyme A (HMG-CoA) reductase is an enzyme that catalyzes the conversion of HMG-CoA to mevalonate, one of the precursors for the production of cholesterol in humans and ergosterol in plants, fungi, and protozoa. Statins are compounds which inhibit this enzyme and so are promising as chemotherapeutics. In order to validate whether this enzyme could be an interesting therapeutic target in Acanthamoeba, small interfering RNAs (siRNAs) against HMG-CoA were developed and used to evaluate the effects induced by the inhibition of Acanthamoeba HMG-CoA. It was found that HMG-CoA is a potential drug target in these pathogenic free-living amoebae, and various statins were evaluated in vitro against three clinical strains of Acanthamoeba by using a colorimetric assay, showing important activities against the tested strains. We conclude that the targeting of HMG-CoA and Acanthamoeba treatment using statins is a novel powerful treatment option against Acanthamoeba species in human disease.     

The role of aggressions suffered by healthcare workers as predictors of burnout

Aims and objectives. To examine the prevalence of aggression against healthcare professionals and to determine the possible impact that violent episodes have on healthcare professionals in terms of loss of enthusiasm and involvement towards work. The objective was to analyse the percentage of occupational assault against professionals’ aggression in different types of healthcare services, differentiating between physical and verbal aggression as a possible variable in detecting burnout in doctors and nursing professionals. Background. Leiter and Maslach have explored a double process model of burnout not only based on exhaustion by overload, but also based on personal and organisational value conflicts (community, rewards or values). Moreover, Whittington has obtained conclusive results about the possible relationship between violence and burnout in mental health nurses. Design. A retrospective study was performed in three hospitals and 22 primary care centres in Spain (n = 1·826). Methods. Through different questionnaires, we have explored the relationship between aggression suffered by healthcare workers and burnout. Results. Eleven percent of respondents had been physically assaulted on at least one occasion, whilst 34·4% had suffered threats and intimidation on at least one occasion and 36·6% had been subjected to insults. Both forms of violence, physical and non‐physical aggression, showed significant correlations with symptoms of burnout (emotional exhaustion, depersonalisation and inefficacy). Conclusions. The survey showed evidence of a double process: (1) by which excess workload helps predict burnout, and (2) by which a mismatch in the congruence of values, or interpersonal conflict, contributes in a meaningful way to each of the dimensions of burnout, adding overhead to the process of exhaustion–cynicism–lack of realisation. Relevance to clinical practice. Studies indicate that health professionals are some of the most exposed to disorders steaming from psychosocial risks and a high comorbidity: anxiety, depression, etc. There is a clear need for accurate instruments of evaluation to detect not only the burnout but also the areas that cause it. Professional exhaustion caused by aggression or other factors can reflect a deterioration in the healthcare relationship.     

Mapping of mangrove forests on the southern coast of São Paulo,Brazil, using synthetic aperture radar data from ALOS/PALSAR

Widespread in the coastal zones of (sub)tropical regions, mangroves are an essential habitat for many animal species and provide subsistence resources for many human coastal communities. Among remote sensing techniques, synthetic aperture radar is a particularly advantageous method to monitor mangroves: images are not dependent on cloud cover and can provide information from forest understory. This article mapped mangrove forests in the southern coast of São Paulo State (Brazil) using frequency-based contextual classification of incoherent attributes derived from a multi-polarized Phased Array L-Band Synthetic Aperture Radar (PALSAR) image. The use of 10 incoherent attributes and only 3 Synthetic Aperture Radar (SAR) vegetation indices as input for digital classification showed the best accuracies with kappa index values of 0.739 and 0.734, respectively. HH polarization and SAR vegetation indices were the attributes that contributed most to the mangrove mapping procedure. The use of L-Band SAR data was effective for mapping mangrove areas, and therefore it is recommended as a tool for coastal management.     

Assessment of right ventricular outflow tract in children by two-dimensional echocardiography using a new subcostal view. Angiocardiographic and morphologic correlative study

Evaluation of the right ventricular (RV) outflow tract in congenital heart disease is extremely important for surgical management. Therefore, the value of 2-dimensional echocardiography (2-D echo) to assess the RV outflow tract was studied using a new approach: the subcostal elongated right oblique view. Twenty normal children and 49 children with congenital heart disease, aged 1 day to 11 years, were studied. Significant pulmonary infundibular obstruction was present in 22 patients with conotruncal malformations. To obtain the subcostal elongated right oblique view from the short-axis view at the aortic valve level, the transducer was slightly rotated clockwise with an anterior angulation of about 30 degrees so that the ascending aorta was seen in its long axis, providing an image similar to that obtained by a right ventriculogram in the elongated right anterior oblique view. The deviation of infundibular septum was appreciated by measurement of the angle alpha, defined by the long axis of the infundibular septum and the plane of aortic cusps. This view could be obtained in 64 patients (92%). In correlation with angiographic or anatomic data, the subcostal elongated right oblique view permitted recognition of several types of RV outflow tract: type I--normally formed RV outflow tract; type II--disorganized RV outflow tract with obstruction (alpha less than 90 degrees); type III and IV--disorganized RV outflow tract with obstruction (alpha greater than 90 degrees). This view could visualize the crista supraventricularis in type I, but also the anatomic components of RV outflow tract that may contribute to obstruction in the other types: infundibular septum, septoparietal trabeculations and trabecula septomarginalis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Use of somatostatin analogue scintigraphy in the localization of recurrent medullary thyroid carcinoma

Detection of recurrence of medullary thyroid carcinoma (MTC) remains a diagnostic problem. Increased serum tumour marker levels frequently indicate recurrence while conventional imaging techniques (CIT) are non-diagnostic. In this study, we performed indium-111 octreotide scintigraphy and CIT in a series of 20 patients with MTC presenting with elevated serum tumour markers after surgery. ¹¹¹In-octreotide whole-body studies detected 15 pathological uptake foci in 11 of the 20 patients studied and CIT detected 17 lesions in 11 of the 20 patients. Ten patients underwent reoperation, five of them with positive ¹¹¹In-octreotide scintigraphy and CIT and two with positive isotopic exploration and negative CIT. Surgical findings demonstrated that the results of isotopic study and CIT had been false-positive for MTC in one case (sarcoidosis). The six patients with true-positive ¹¹¹In-octreotide studies had significantly higher basal calcitonin (CT) and carcinoembryonic antigen (CEA) levels than the patients with negative isotopic studies. The expression of somatostatin receptor (SSTR) subtypes by PC-PCR could be investigated in four cases with a positive isotopic study. Among the three cases with a true-positive study, SSTR2, the SSTR subtype that preferentially binds to the somatostatin analogue octreotide, was detected in two, SSTR5 was demonstrated in the three, and SSTR3 was detected in one. No subtype of SSTR was detected in the case with a final diagnosis of sarcoidosis. We conclude that ¹¹¹In-octreotide has limited sensitivity in detecting recurrence in patients with MTC, although its sensitivity may improve with high serum CT levels. This radionuclide imaging technique should be employed when conventional imaging techniques are negative or inconclusive or when the presence of somatostatin receptors may provide the basis for treatment with somatostatin analogues. Received 5 April and in revised form 27 July 1998     

Unconsciousness and sedation as precipitating factors of diabetic ketoacidosis

The aim of this study was to identify medico-legal situations characterized by increased vitreous glucose concentrations, potentially lethal blood 3-hydroxybutyrate levels and conditions that could either incapacitate or lead to death on their own. The above was investigated in order to verify whether prolonged states of unconsciousness may play a role in precipitating diabetic ketoacidosis. Six groups of medico-legal situations (corresponding to 206 autopsy cases) were identified. Among these, three cases were characterized by pathologically increased vitreous glucose and blood 3-hydroxybutyrate levels. In one case diabetic ketoacidosis coexisted with underlying features that might have potentially incapacitated or lead to death on their own, whereas in two cases it corresponded with potentially lethal or lethal drug concentrations. The results of this study highlight the usefulness of systematically performing biochemistry in order to identify diabetic ketoacidosis-related deaths, even when autopsy and toxicology results provide apparently conclusive findings.     

Human plasma as a dermal scaffold for the generation of a completely autologous bioengineered skin

BACKGROUND: Keratinocyte cultures have been used for the treatment of severe burn patients. Here, we describe a new cultured bioengineered skin based on (1) keratinocytes and fibroblasts obtained from a single skin biopsy and (2) a dermal matrix based on human plasma. A high expansion capacity achieved by keratinocytes grown on this plasma-based matrix is reported. In addition, the results of successful preclinical and clinical tests are presented. METHODS: Keratinocytes and fibroblasts were obtained by a double enzymatic digestion (trypsin and collagenase, respectively). In this setting, human fibroblasts are embedded in a clotted plasma-based matrix that serves as a three-dimensional scaffold. Human keratinocytes are seeded on the plasma-based scaffold to form the epidermal component of the skin construct. Regeneration performance of the plasma-based bioengineered skin was tested on immunodeficient mice as a preclinical approach. Finally, this skin equivalent was grafted on two severely burned patients. RESULTS: Keratinocytes seeded on the plasma-based scaffold grew to confluence, allowing a 1,000-fold cultured-area expansion after 24 to 26 days of culture. Experimental transplantation of human keratinocytes expanded on the engineered plasma scaffold yielded optimum epidermal architecture and phenotype, including the expression of structural intracellular proteins and basement-membrane components. In addition, we report here the successful engraftment and stable skin regeneration in two severely burned patients at 1 and 2 years follow-up. CONCLUSIONS: Our data demonstrate that this new dermal equivalent allows for (1) generation of large bioengineered skin surfaces, (2) restoration of both the epidermal and dermal skin compartments, and (3) functional epidermal stem-cell preservation.