Chemisorption-repulsion energies of H2 on surface (110) of Mg1-xMx alloys (M = Al, Ni, Zn; 0.0 ≤ x ≤ 0.20) as a function of temperature

In recent years, the popularity of metal hydrides has increased considerably for hydrogen storage and their applications in hydrogen fuel cells. Their potential applications for clean energy are promissory. However, the temperatures required for adsorption and desorption are extremely high, which range between 500 and 700 K, making their use impractical. To overcome these difficulties, the following work considers using three hydride alloys: magnesium-aluminum (MgAl), magnesium-nickel (MgNi), and magnesium-zinc (MgZn). The Mg concentrations were set to be between 80 and 100 wt% in order to reduce the temperatures of adsorption and desorption in contrast with the temperatures of pure magnesium. The chemisorption and repulsion energies of the hydrogen molecule on the surface (110) of the different metallic alloys were studied at 0, 200, 400, 600, and 700 K, respectively. The study was based on the density functional theory (DFT), with the module DMol³ of the molecular simulation program Materials Studio, which was used to obtain these energy values. The results confirm that adding aluminum, nickel, or zinc into magnesium matrix increases the chemisorption and decreases the energy repulsion values on surfaces of the metallic alloys, improving the effectiveness of the hydrogen storage.

Inducing ovulation with hCG in a five-day progesterone-based fixed-time AI protocol improves the fertility of anestrous dairy cows under heat stress conditions

This study compares the fertility effects of inducing ovulation using human chorionic gonadotropin (hCG) versus gonadotropin releasing hormone (GnRH) at the end of a 5-day progesterone(P4)-based protocol for fixed-time artificial insemination (FTAI) in heat-stressed and non-heat stressed anestrous lactating dairy cows. Heat stress (HS) was defined as an environmental temperature-humidity index (THI) > 72. A P4 intravaginal device (CIDR) was fitted for five days and GnRH administered upon CIDR insertion and a double dose (24 h apart) of prostaglandin F_2α upon CIDR removal. Cows then received either GnRH (GnRH group; n = 506), or hCG (hCG group; n = 493) 36 h after CIDR removal and were inseminated 50-56 h after CIDR removal. Ovulation failure was investigated in a subset of 425 cows: 223 and 202 receiving GnRH and hCG, respectively. Based on odds ratios, the interaction between treatment and HS had a significant effect on the ovulation failure rate (P = 0.01). This meant that compared to the rates recorded in non-heat-stressed, GnRH-treated cows (13%), ovulation failure in heat-stressed GnRH-treated cows (25.3%) was more likely by a factor of 2.3 (P = 0.04), in non-heat-stressed hCG-treated cows (2.3%) was less likely by a factor of 0.16 (P = 0.02) and was not significantly different in heat-stressed hCG-treated cows (7%). Interactions between treatment and HS and between treatment and parity had a significant effect on the pregnancy rate (P = 0.0001 and P = 0.001, respectively). The treatment-HS interaction determined that compared to the rates recorded in non-heat-stressed, GnRH-treated cows (30.5%), pregnancy in heat-stressed GnRH-treated cows (17.6%) was less likely by a factor of 0.48 than the remaining cows (P = 0.001), whereas because of the treatment-parity interaction, compared to the rates recorded in primiparous, GnRH-treated cows (31.4%), pregnancy in GnRH-treated multiparous cows (18.9%) was less likely to conceive by a factor of 0.51 than the remaining cows (P = 0.002). No significant effects of treatment on the rates of pregnancy loss or twin pregnancy were identified by binary logistic regression. In conclusion, hCG treatment given at the end of a 5-day P4-based protocol for FTAI improved ovulation and pregnancy rates in anestrous cows under conditions of HS and also had a beneficial impact on the pregnancy rate in anestrous multiparous cows throughout the year.

[Quality of care and safety indicators in anticoagulated patients with non-valvular auricular fibrillation and deep venous thromboembolic disease]

OBJECTIVES

To identify and prioritise indicators to assess the quality of care and safety of patients with non-valvular auricular fibrillation (NVAF) and deep vein thrombosis (DVT) treated with anticoagulants.

MATERIALS AND METHODS

Using the consensus conference technique, a group of professionals and clinical experts, the determining factors of the NVAF and DVT care process were identified, in order to define the quality and safety criteria. A proposal was made for indicators of quality and safety that were prioritised, taking into account a series of pre-established attributes. The selected indicators were classified into indicators of context, safety, action, and outcomes of the intervention in the patient.

RESULTS

A set of 114 health care and safety quality indicators were identified, of which 35 were prioritised: 15 for NVAF and 20 for DVT. About half (49%) of the indicators (40% for NVAF and 55% for DVT) applied to patient safety, and 26% (33% for NVAF and 20% for DVT) to the outcomes of interventions in the patient.

CONCLUSIONS

The present work presents a set of agreed indicators by a group of expert professionals that can contribute to the improvement of the quality of care of patients with NVAF and DVT treated with anticoagulants.

Infrastructure and equipment for radiation oncology in the Spanish National Health System: analysis of external beam radiotherapy 2015-2020

PURPOSE

Planning for radiation oncology requires reliable estimates of both demand for radiotherapy and availability of technological resources. This study compares radiotherapy resources in the 17 regions of the decentralised Spanish National Health System (SNHS).

MATERIALS AND METHODS

The Sociedad Española de Oncología Radioterápica (SEOR) performed a cross-sectional survey of all Spanish radiation oncology services (ROS) in 2015. We collected data on SNHS radiotherapy units, recording the year of installation, specific features of linear accelerators (LINACs) and other treatment units, and radiotherapeutic techniques implemented by region. Any machine over 10 years old or lacking a multileaf collimator or portal imaging system was considered obsolete. We performed a k-means clustering analysis using the Hartigan-Wong method to test associations between the gross domestic regional product (GDRP), the number of LINACs per million population and the percentage of LINACs over 10 years old.

RESULTS

The SNHS controls 72 (61%) of the 118 Spanish ROS and has 180 LINACs, or 72.5% of the total public and private resources. The mean rate of LINACs per million population is 3.9 for public ROS, and 42% (n = 75) of the public accelerators were obsolete in 2015: 61 due to age and 14 due to technological capability. There was considerable regional variation in terms of the number and technological capacity of radiotherapy units; correlation between GRDP and resource availability was moderate.

CONCLUSION

Despite improvements, new investments are still needed to replace obsolete units and increase access to modern radiotherapy. Regular analysis of ROS in each Spanish region is the only strategy for monitoring progress in radiotherapy capacity.

Allergic Rhinitis and its Impact on Asthma (ARIA): achievements in 10 years and future needs

Allergic rhinitis (AR) and asthma represent global health problems for all age groups. Asthma and rhinitis frequently coexist in the same subjects. Allergic Rhinitis and its Impact on Asthma (ARIA) was initiated during a World Health Organization workshop in 1999 (published in 2001). ARIA has reclassified AR as mild/moderate-severe and intermittent/persistent. This classification closely reflects patients' needs and underlines the close relationship between rhinitis and asthma. Patients, clinicians, and other health care professionals are confronted with various treatment choices for the management of AR. This contributes to considerable variation in clinical practice, and worldwide, patients, clinicians, and other health care professionals are faced with uncertainty about the relative merits and downsides of the various treatment options. In its 2010 Revision, ARIA developed clinical practice guidelines for the management of AR and asthma comorbidities based on the Grading of Recommendation, Assessment, Development and Evaluation (GRADE) system. ARIA is disseminated and implemented in more than 50 countries of the world. Ten years after the publication of the ARIA World Health Organization workshop report, it is important to make a summary of its achievements and identify the still unmet clinical, research, and implementation needs to strengthen the 2011 European Union Priority on allergy and asthma in children.

Mitochondrial cholesterol in health and disease

Cholesterol is a critical component of biological membranes, which not only plays an essential role in determining membrane physical properties, but also in the regulation of multiple signaling pathways. Cells satisfy their need for cholesterol either by uptake from nutrients and lipoproteins or de novo synthesis from acetyl-CoA. The latter process occurs in the endoplasmic reticulum, where transcription factors that regulate the expression of enzymes involved in the de novo cholesterol synthesis reside. Cholesterol is distributed to different membranes most prominently to plasma membrane, where it participates in the physical organization of specific membrane domains. Mitochondria, however, are considered cholesterol-poor organelles, and obtain their cholesterol load by the action of specialized proteins involved in its delivery from extramitochondrial sources and trafficking within mitochondrial membranes. Although mitochondrial cholesterol fulfills vital physiological functions, such as the synthesis of bile acids in the liver or the formation of steroid hormones in specialized tissues, recent evidence indicates that the accumulation of cholesterol in mitochondria may be a key step in disease progression, including steatohepatitis, carcinogenesis or Alzheimer disease.

Method for the development of topical medicinal aerosols using liquified hydrocarbon gas

Low chain liquid hydrocarbons (LH) at room temperature and atmospheric pressure can be used to simulate the effect of gas hydrocarbons (GH) in aerosol systems without the need of using pressured flasks. Samples of different tetracycline formulations were tested with LH and GH in order to study their behaviour and physicochemical stability in the system. The results showed a similar behaviour between samples when LH or GH were used, suggesting the use of LH to simulate the effect of GH introduction in the system, as a useful predictive method for the development of pressured aerosol formulations without using pressured containers in early steps of the process, such as pre-formulation studies.

BanTeC: a software tool for management of corneal transplantation

BACKGROUND

Until recently, all cornea information at our tissue bank was managed manually, no specific database or computer tool had been implemented to provide electronic versions of documents and medical reports. The main objective of the BanTeC project was therefore to create a computerized system to integrate and classify all the information and documents used in the center in order to facilitate management of retrieved, transplanted corneal tissues.

MATERIALS AND METHODS

We used the Windows platform to develop the project. Microsoft Access and Microsoft Jet Engine were used at the database level and Data Access Objects was the chosen data access technology.

CONCLUSIONS

In short, the BanTeC software seeks to computerize the tissue bank. All the initial stages of the development have now been completed, from specification of needs, program design and implementation of the software components, to the total integration of the final result in the real production environment. BanTeC will allow the generation of statistical reports for analysis to improve our performance.

CARREL: an internet platform for the distribution of human organs for transplantation

BACKGROUND

Human organs for transplant from a deceased donor are presently distributed in Spain by means of manual handling and telephone or fax transmission of data. This procedure is conducted organ by organ with the information transmitted sequentially. This process has several inherent drawbacks, the main one being the long length of time to allocate organs on many occasions. A difficulty of this type could be solved by means of an electronic system of data management and transmission through the Internet. CARREL is a platform that could provide an alternative organ distribution procedure. The main objective of CARREL was to increase the efficiency, safety, rapidity, and quality of organ distribution for transplantation, thereby helping the allocation process.

MATERIALS AND METHODS

CARREL is a database system, accessible through the Internet, to which any medical center authorized to perform organ transplants in Spain may subscribe. CARREL allows information share between centers, including administrative, anthropometric, immunological, analytical, and clinical data, as well as parameters concerning donor maintenance.

CONCLUSIONS

CARREL is an online system that can reduce organ distribution time, directly store complete information concerning the donor, and also share data between centers. It facilitates communication between transplant coordinators at different centers, thereby improving and hastening candidate selection.

Cell cycle arrest and modulation of HO-1 expression induced by acetyl salicylic acid in hepatocarcinogenesis

BACKGROUND AND AIMS

Control of cell proliferation is important for cancer prevention since cell proliferation has an essential role in carcinogenesis. In rodent carcinogenesis models, antioxidant agents suppress carcinogen-induced cellular hyper proliferation in the target organs. Strict control of cell division is an essential process to ensure that DNA synthesis and mitotic division are accurately and coordinately executed. We studied the interplay between cell cycle and heme oxygenase-1 (HO-1) and the effect of the acetylsalicylic acid (ASA) in hepatic carcinogenesis.

METHODS

Male CF1 mice pre-treated with dietary p-dimethylaminoazobenzene (DAB; 0.5%, w/w) were fed with ASA (0.16%, w/w). We investigated the hepatic expression of cyclin D1, cyclin E, Cdk2, Cdk4, p21, p27, p53; the level of bcl-2, an antiapoptotic protein and of heme oxygenase-1 (HO-1), a marker of oxidative stress, by Western blot analysis.

RESULTS

The treatment with ASA produced an important attenuation in the induction of cyclin E and cyclin D1 provoked by DAB. p21 and p27 levels were increased when animals received both drugs. The administration of ASA to DAB treated animals induced Cdk2 (29%). HO-1 induction (65%) provoked by DAB was diminished by ASA administration reaching lower induction levels (23%).

CONCLUSION

The deregulation of cyclin/CDK expression and the up-regulation of p21 and p27 with the administration of ASA, post-treatment of the carcinogen administration, would block the pass through out to the G0/G1 check point to permit the cells to repair their DNA and HO-1 protected the liver from reactive oxygen species produced from DAB.

[Jejunostomy for enteral feeding in surgery. Technical contribution and experience]

The necessity to maintain the nutritional integrity in patients subjected to major surgery of the superior digestive tract has been broadly accepted. The enteral nutrition for yeyunostomy is accepted as more physiologic, sure and effective than the parenteral one.

MATERIALS AND METHOD

171 yeyunostomies were indicated in: 151 patients with malignant neoplasm of the superior digestive tract, 15 with infected pancreatic necrosis, 3 bile-duodenum-pancreatic traumatisms and in 1 stenosis for gastroesophagic reflux. Depending on the pathological type, a yeyunostomy using the Witzell technique was carried out with either local or general anesthesia at a 15 to 20 cm. of the Treitz angle. To facilitate the fixation of the catheter and to avoid the stenosis of the jejunum we have incorporated, as an original technical detail, the proximal serous section with cold scalpel in about 4 cm, that is to say in the sector to be tunneled.

RESULTS

There was not mortality in relation to the yeyunostomy. Among the minor complications we emphasize the abdominal distension, colic pain and diarrhea, situations that were reverted, controlling the debit and the feeding characteristics. This approach could be maintained for period of 2 months and in some cases at home.

CONCLUSIONS

We emphasize the great importance of the enteral feeding for yeyunostomy, for its of easy handling, security and low cost that, together with the suggested technical detail, has allowed us to obtain a deeding road almost without inherent complications.

Amniotic membrane transplantation for ocular surface pathology: long-term results

Amniotic membrane transplantation has been used for >90 years for cutaneous and mucous lesions for regeneration of tissues. In recent years its effectiveness has been demonstrated in the treatment of diseases of the ocular surface. We present our experience with 53 amniotic membrane transplantations for different ocular pathologies with two different forms of implantation. The 53 cases were divided into three groups according to pathology and type of implant. Group 1 included 24 eyes with amniotic membrane grafts after resection of extensive conjunctival lesions. Group 2 included 19 eyes with amniotic membrane grafts for corneal pathology, and group 3 consisted of 10 eyes with amniotic membrane patches for corneal epithelial defects without ulceration. No intra- or postoperative complications were observed during an average follow-up period of 32 months (24-48 months). Group 1 demonstrated rapid healing of the lesions with minimal scarring in all cases. In group 2 a favorable response was observed in 16 of 19 cases. In group 3 complete healing was achieved in only 3 of 10 cases, and the time for which the graft remained was related to the success of the treatment. The primary intention was to achieve prolonged fixation of the implant. Finally, amniotic membrane transplantation is a safe and effective technique for the treatment of different pathologies of the ocular surface. After the resection of extensive conjunctival lesions it is currently the preferred treatment. In corneal pathology, it represents an additional therapeutic alternative when conservative medical treatments fail.

Formalizing an electronic institution for the distribution of human tissues

The use of multi-agent systems (MAS) in health-care domains is increasing. Such agent-mediated medical systems can manage complex tasks and have the potential to adapt gracefully to unexpected events. However, in these kinds of systems the issues of privacy, security and trust are particularly sensitive in relation to matters such as agents' access to patient records, what is acceptable behaviour for an agent in a particular role and the development of trust both between (heterogeneous) agents and between users and agents. To address these issues we propose a formal normative framework, deriving from and developing the notion of an electronic institution. Such institutions provide a framework to define and police norms that guide, control and regulate the behaviour of the heterogeneous agents that participate in the institution. These norms define the acceptable actions that each agent may perform depending on the role or roles it is playing, and clearly specifies the data it may access and/or modify in playing those roles. In this paper, we present the formalization of Carrel, a virtual organization for the procurement of organs and tissues for transplantation purposes, as an electronic institution using the ISLANDER institution specification language as formalizing languages. We demonstrate aspects of the formalization of such an institution, example fragments in the language used for the textual specification, and how such formalization can be used as a blueprint in the implementation of the final agent architecture, through techniques such as skeleton generation.

Short- and long-term success of organs transplanted from acute methanol poisoned donors

BACKGROUND

The shortage of organs for transplantation has made it necessary to extend the criteria for the selection of donors, among others including those patients who die because of toxic substances such as methanol. Methanol is a toxic which is distributed through all the systems and viscera of the organism and tends to cause a severe metabolic acidosis. It can specifically cause serious or irreversible lesions of the central nervous system (CNS) and retina, and ultimately brain death. We present our experience with 16 organ donors who died as a result of acute methanol intoxication in 10 Spanish hospitals over the last 14 yr.

PATIENTS AND METHODS

Between October 1985 and July 1999, 16 organ donors with brain death caused by acute methanol intoxication, 13 females and three males with a mean age of 38.4 +/- 7.6 yr (interval: 26-55 yr), allowed 37 elective transplants to be performed: 29 kidneys, four hearts and four livers for 37 recipients, and one urgent liver transplantation to a recipient with fulminant hepatitis.

RESULTS

The immediate postoperative period was favourable for the 38 graft recipients. None of the graft recipients presented gap anion metabolic acidosis in the immediate postoperative period, nor symptomatology or lesions of the CNS characteristic of methanol intoxication. Two patients died during the first month post-transplantation, a liver recipient and a heart recipient, at 16 and 24 days, respectively, because of acute rejection of the graft. At 1 month after transplantation 35 of the 36 recipients had been discharged from hospital with normal-functioning grafts. The last of the recipients, a kidney recipient, was discharged at 6 wk with normal-functioning graft. Actuarial survival of the graft and patient of kidney recipients at 1, 3 and 5 yr was 92.6, 77.8, and 75%, and 100, 88.9 and 83.3%, respectively; with average serum creatinines of 139.9 +/- 42.9, 150.4 +/- 42.8, and 164.4 +/- 82.5 micromol/L, respectively. At 1 yr after transplantation the three heart recipients and two of the three liver recipients had normal-functioning graft.

CONCLUSIONS

Methanol intoxication is not transferred from the donor to the recipient. The survival of the graft and kidney, heart and liver recipients using organs from donors who die because of methanol does not differ in the short- and long-term from the transplants performed with organs from donors who die from other causes.

Elderly donor kidney grafts into young recipients: results at 5 years

BACKGROUND

To date, few data are available on older donor renal grafts transplanted into young recipients. We compare 63 kidneys grafts from donors older than 60 years transplanted into recipients younger than 60 years (group 1) with a control group of 235 patients in whom both recipients and donors were younger than 60 years (group 2).

RESULTS

Patient survival rates at 1 and 5 years, respectively, were 98% and 95% (group 1) and 95% and 84% (group 2) (P=0.01). Graft survival rates were 95% and 83% in group 1 versus 94% and 81% in group 2, although death censoring was significant (100% and 98% group 1 vs. 96% and 86% group 2, P=0.04). In group 1, plasmatic creatinemia was significantly higher. The aged donor, female donor-male recipient combination, and the presence of acute rejection alone or together with acute tubular necrosis, were determinants for worse renal functioning at 1 year after transplantation. Seven patients had chronic nephropathy not related to any clinical parameter.

CONCLUSION

We conclude that kidneys from older donors can be successfully transplanted to younger patients.

Group B Streptococcal sacroiliitis: case report and review

Streptococcus agalactiae, or group B Streptococcus (GBS), is the major cause of neonatal meningitis and sepsis but is an uncommon infection in adults. GBS arthritis is rare, and axial involvement with sacroiliitis is even more uncommon. Microbiological diagnosis frequently relies upon positive blood cultures as synovial fluid cultures are usually negative. Severe joint damage may result due to delay in the initiation of antibiotic treatment.

Interaction of cimetidine with P450 in a mouse model of hepatocarcinogenesis initiation

Many drugs and xenobiotics are lipophilic and they should be transformed into more polar water soluble compounds to be excreted. Cimetidine inhibits cytochrome P450. The aim of this study was to investigate the preventive and/or reversal action of cimetidine on cytochrome P450 induction and other metabolic alterations provoked by the carcinogen p-dimethylaminoazobenzene. A group of male CF1 mice received a standard laboratory diet and another group was placed on dietary p-dimethylaminoazobenzene (0.5% w w(-1). After 40 days of treatment, animals of both groups received p-dimethylaminoazobenzene and two weekly doses of cimetidine (120 mg kg(-1), i.p.) during a following period of 35 days. Cimetidine prevented and reversed delta-aminolevulinate synthetase induction and cytochrome P450 enhancement provoked by p-dimethylaminoazobenzene. However, cimetidine did not restore haem oxygenase activity decreased by p-dimethylaminoazobenzene. Enhancement in glutathione S-transferase activity provoked by p-dimethylaminoazobenzene, persisted in those animals then treated with cimetidine. This drug did not modify either increased lipid peroxidation or diminution of the natural antioxidant defence system (inferred by catalase activity) induced by p-dimethylaminoazobenzene. In conclusion, although cimetidine treatment partially prevented and reversed cytochrome P450 induction, and alteration on haem metabolism provoked by p-dimethylaminoazobenzene AB, it did not reverse liver damage or lipid peroxidation. These results further support our hypothesis on the necessary existence of a multiple biochemical pathway disturbance for the onset of hepatocarcinogenesis initiation.

On the promoting action of tamoxifen in a model of hepatocarcinogenesis induced by p-dimethylaminoazobenzene in CF1 mice

BACKGROUND AND AIMS

Tamoxifen (TMX) has proven to be an effective palliative treatment for advanced breast cancer with low reported incidence of side effects. TMX has been demonstrated to be an initiator and/or a promoter in the rat model of hepatocarcinogenesis. To document the long-term effect of TMX in mice treated with p-dimethylaminoazobenzene (DAB), we have investigated the time response action of these drugs on different biochemical parameters.

METHODS

A group of animals was placed on dietary DAB (0.5%, w/w) during a period of 28 weeks. Control animals received a standard laboratory diet. Two other groups of non-treated and DAB-treated animals received TMX citrate (0.025%, w/w) in the diet since day 20.

RESULTS

The activities of the enzymes involved in heme synthesis and degradation as evaluated in the DAB group was not further affected by TMX. DAB and/or TMX treatment significantly increased the content of total cytochrome P450 and also the activity of glutathione S-transferase indicating liver damage. In all treated groups oxidative stress and an adaptive response of the natural defense system (catalase and superoxide dismutase) were demonstrated. Histological and morphological studies revealed liver cell hyperplasia in DAB treated group; however, only in the DAB+TMX group solid, trabecular and acinar hepatocellular carcinoma was confirmed at the end of the experimental trial.

CONCLUSION

We have demonstrated that TMX produced changes in hepatic enzyme activities which may be relevant for the metabolism and disposition of this and/or other drugs. Because liver tumors could be initiated and promoted by several agents which need to be activated, the possible hazard of TMX should be considered. This study reports that long-term treatment with TMX enhances hepatocarcinogenesis induced by DAB. The widespread use of TMX as an anticancer agent adds to the significance of this study.

Application of the amniotic membrane in ocular surface pathology

The amnion is a fine semi-transparent membrane that has been used in clinical practice to encourage epithelization in burns, in skin ulcers, or as a skin graft. Application in ocular surface disorders first took place in 1940. We carried out the membrane amniotic implantation on 11 patients with different pathologies: three cases of limbal stem cell deficiency (caustication with failure of prior keratoplasty, congenital aniridia and post-radiotherapy keratopathy), one case with persistent neurotrophic corneal ulcer after prior keratoplasty, four cases with epithelial defect of long evolution, one case of extensive Salzmann's degeneration of the cornea, and two cases after the resection of conjunctival tumour. The follow-up period varied between 2 and 6.5 months (mean = 4 months). Amniotic membrane was obtained by elective Caesarean, and it was preserved at -80 degrees C. In all transplanted patients the reabsorption of the amniotic membrane took place between the third and the fifth week. In the cases of resection of conjunctival tumour the epithelialization was completed between the first and the second post-operative week, with minimal residual scarring. In the other cases, with affliction of the corneal epithelium, the complete epithelialization, together with a marked reduction in the inflammatory response, occurred in all except 2 cases. In conclusion, the implantation of preserved human amniotic membrane can favour the recovery of a normal ocular surface in different pathologies, both in corneal and conjunctival lesions.

Early diagnosis of brain death in patients treated with central nervous system depressant drugs

BACKGROUND

Among the main causes for the relatively small number of organ donors, the delay in the diagnosis of brain death plays a major role. Administration of drugs causing central nervous system (CNS) depression prevents diagnosis of brain death by clinical and electroencephalographic criteria until serum clearance of the drug has occurred. Confirming brain death by demonstrating persistent intracranial circulatory arrest might decrease the length of the diagnostic process. We have carried out a prospective study to investigate whether 99 mTc-hexamethyl propylenamino oxime (99mTc-HMPAO) brain scintigraphy and/or transcranial Doppler ultrasound can speed up the diagnosis of brain death in patients treated with CNS depressant drugs.

METHODS

All 138 consecutive patients with severe brain lesion that progressed to brain death in our center between January 1994 and December 1996 were controlled. Of them, 36 patients aged 1 to 65 years old (mean=25.6+/-18.3 years) who met clinical and EEG criteria for the diagnosis of brain death, except for the presence of significant serum levels of barbiturates (n=34), opiates (n=8), and benzodiazepines (n=3) were distributed in three groups according to the confirmatory test used; group 1: waiting for the metabolic clearance of CNS depressant drugs, or by demonstrating intracranial circulatory arrest with 99mTc-HMPAO (group 2) or transcranial Doppler (group 3). The delay in diagnosing brain death by the three methods was analyzed.

RESULTS

The mean interval between the presumptive and the definitive diagnosis of brain death was 34.4+/-32.2 hr in group 1, 17.7+/-18.3 hr in group 2, and 5.0+/-4.6 hr in group 3 (P=0.004). The between-groups analysis showed that 99mTc-HMPAO and transcranial Doppler decreased the delay in diagnosing brain death with respect to waiting for drug clearance by 49% (P=0.16) and 85% (P<0.001), respectively. Moreover, transcranial Doppler decreased this time by 72% with respect to 99mTc-HMPAO (P<0.01).

CONCLUSIONS

Transcranial Doppler ultrasound and 99mTc-HMPAO brain scintigraphy can significantly reduce the time taken to confirm brain death in patients with significant serum levels of CNS depressant drugs. In this setting, transcranial Doppler is superior to 99mTc-HMPAO in reducing the waiting time for a firm diagnosis of brain death.

Preventive aspirin treatment of streptozotocin induced diabetes: blockage of oxidative status and revertion of heme enzymes inhibition

Some late complications of diabetes are associated with alterations in the structure and function of proteins due to glycation and free radicals generation. Aspirin inhibits protein glycation by acetylation of free amino groups. In the diabetic status, it was demonstrated that several enzymes of heme pathway were diminished. The aim of this work has been to investigate the in vivo effect of short and long term treatment with acetylsalicylic acid in streptozotocin induced diabetic mice. In both treatments, the acetylsalicylic acid prevented delta-aminolevulinic dehydratase and porphobilinogen deaminase inactivation in diabetic mice and blocked the accumulation of lipoperoxidative aldehydes. Catalase activity was significantly augmented in diabetic mice and the long term treatment with aspirin partially reverted it. We propose that oxidative stress might play an important role in streptozotocin induced diabetes. Our results suggest that aspirin can prevent some of the late complications of diabetes, lowering glucose concentration and probably inhibiting glycation by acetylation of protein amino groups.

[Value of the nuclear magnetic cholangio resonance in the study of the patient with jaundice]

This report analyse the results about forty three (43) patients, thirty six (36) of which showed an extrahepatic obstructive biliary Syndrome was made evident by ultrasonography, five (5) with a cholecistolithiasis and doubtful history of jaundice were evaluated to carry out a video-surgery procedure and two (2) patients whom hepatic-yeyunostomy had been practiced, a control of anastomosis in postoperative period was required. Nuclear Magnetic Resonance and Operative Cholangiography findings were correlated and afterward with the anatomopathological studies when they arrived. In all cases the Nuclear Magnetic Cholangio Resonance (NMCR) let us prove the diagnosis of extrahepatic biliary obstruction determining with precision furthermore the topographical site of the lesion. Respecting the aetiology of obstruction, NMCR was accurate in 34 out of 36 cases (94.4%). In conclusion Cholangio-Resonance is an excellent diagnostic method to evaluate biliary ductal system including anatomic changes. However, there are some limitations yet in order to determine the aetiology of lesions about extrahepatic biliary via extremes. We emphasize its features such as non-invasive, little operating dependent, and without morbimortality that become it as a method of choice to study the biliary via from a diagnostic viewpoint.

Decerebrate-like posturing with mechanical ventilation in brain death

Complex spinal cord, spontaneous, or upper limb reflexes are rarely observed in brain death. The authors describe two brain-dead heart-beating cadavers (out of 400 consecutive cases in their hospital in the past 9 years) that, immediately after brain-death diagnosis, exhibited symmetric upper limb movements resembling decerebrate posture that were triggered by each mechanical pulmonary insufflation, and also by superficial pressure and noxious stimuli applied to the arms, thorax, or abdomen. These movements persisted until disconnection from mechanical ventilation.

Drug metabolizing enzyme system and heme pathway in hepatocarcinogenesis

Chemically induced and spontaneous liver tumors share some metabolic alterations. The decline in hemoprotein levels during hepatocarcinogenesis may result from a diminution of the intracellular heme pool. To elucidate if the onset of the pre-initiation stage alters the natural regulation mechanism of heme pathway, animals were fed with p-dimethylaminoazobenzene (DAB) and treated or not with 2-allylisopropylacetamide (AIA). The induction of 6-Aminolevulinic acid synthase (ALA-S) activity and the diminution in microsomal heme oxygenase (MHO) did not change when DAB fed animals were treated with AIA. Cytochrome P-450 (P-450) levels and glutathione S-transferase activity were increased in all the groups tested. Tryptophan pyrrolase, sulphatase and beta-glucuronidase activities were altered in DAB fed animals but AIA treatment did not produce any effect. Changes in drug metabolizing enzymes in livers of DAB fed animals could be the result of a primary deregulation of heme metabolism. These results give additional support to our hypothesis about a mechanism for the onset of hepatocarcinogenesis.