RESUMEN
Antimicrobial Susceptibility Testing is mandatory for Bloodstream Infections management in order to establish appropriate antimicrobial therapy. Herein we evaluated new approach based on AST results directly from positive blood cultures, using Microscan WA to carry out rapid phenotypical profile of antibiotic resistance. Our investigations allow to reduce time versus traditional results.
Asunto(s)
Antibacterianos/farmacología , Bacteriemia/microbiología , Bacterias/efectos de los fármacos , Farmacorresistencia Bacteriana , Cultivo de Sangre , Diagnóstico Precoz , Humanos , Fenotipo , Factores de TiempoRESUMEN
Polyomavirus-associated nephropathy (PVAN) has a predilection for kidney rather than for other solid organ transplants such as the liver. Immunosuppression is widely recognized to be a major risk factor for PVAN development. Since end-stage liver disease (ESLD) patients are immunocompromised and immunosuppression is a major cause of BK virus reactivation, we sought to evaluate BK virus replication in patients listed for liver transplantation. From April to October 2010, we enrolled 20 patients listed for liver transplantation. BK virus load was measured by quantitative real-time polymerase chain reaction on plasma and urine samples. Viremia occurred in only 1 among 20 patients. We hypothesized that in ESLD patients, the low prevalence of BK virus infection may be related to the prevalent impairment of antibacterial immunity rather than to the viral-specific one. In BK virus reactivation, not only the immunodepressive state itself, but also the specific immunologic mechanisms involved may have a role.
Asunto(s)
Virus BK/patogenicidad , Enfermedad Hepática en Estado Terminal/cirugía , Riñón/fisiopatología , Trasplante de Hígado , Infecciones por Polyomavirus/virología , Replicación Viral , Virus BK/genética , Enfermedad Hepática en Estado Terminal/inmunología , Enfermedad Hepática en Estado Terminal/fisiopatología , Femenino , Humanos , Italia , Riñón/inmunología , Riñón/virología , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , Infecciones por Polyomavirus/inmunología , Infecciones por Polyomavirus/fisiopatología , ARN Viral/sangre , ARN Viral/orina , Viremia , Listas de EsperaRESUMEN
This is a report concerning human polyomavirus JC (JCV) reactivation in a pediatric patient with Crohn's disease (CD) during the treatment with 5-aminosalicylic acid (5-ASA), a non-steroidal anti-inflammatory drug (NSAID). We examined 9 bioptic samples from three different bowel districts (ileum, cecum, rectum) of this child. These samples were analyzed by Quantitative PCR (Q-PCR) to investigate the presence of JCV DNA. JCV DNA was detected in one rectum biopsy taken two months after 5-ASA treatment. Although our result must be validated in a larger group of subjects and with a longer follow-up period, it underlines the importance of JVC monitoring in CD patients.
Asunto(s)
Enfermedad de Crohn/complicaciones , Virus JC , Infecciones por Polyomavirus/complicaciones , Infecciones por Polyomavirus/virología , Antiinflamatorios no Esteroideos/uso terapéutico , Biopsia , Niño , Colon/patología , Colon/virología , Colonoscopía , Enfermedad de Crohn/dietoterapia , Enfermedad de Crohn/tratamiento farmacológico , ADN Viral/genética , Femenino , Humanos , Intestinos/patología , Intestinos/virología , Mesalamina/uso terapéutico , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Lung cancer remains a leading cause of disease globally, with smoking being the largest single cause. Phase I enzymes, including cytochrome P(450), family 1, subfamily A, polypeptide 1 (CYP1A1), are involved in the activation of carcinogens, such as polycyclic aromatic hydrocarbons, to reactive intermediates that are capable of binding covalently to DNA to form DNA adducts, potentially initiating the carcinogenic process. The aim of the present study was to investigate the association of CYP1A1 gene polymorphisms and haplotypes with lung cancer risk. A case-control study was carried out on 1,040 nonsmall cell lung cancer (NSCLC) cases and 784 controls to investigate three CYP1A1 variants, CYP1A1*2A (rs4646903; thymidine to cytosine substitution at nucleotide 3801 (3801T>C)), CYP1A1*2C (rs1048943; 2455A>G; substitution of isoleucine 462 with valine (exon 7)) and CYP1A1*4 (rs1799814; 2453C>A; substitution of threonine 461 with asparagine (exon 7)) using PCR restriction fragment length polymorphism methods. The CYP1A1*2A and CYP1A1*2C variants were significantly over-represented in NSCLC cases compared with controls, whereas the CYP1A1*4 variant was under-represented. CYP1A1 haplotypes (in allele order CYP1A1*4, CYP1A1*2C, CYP1A1*2A) CGC and CGT were associated with an increased risk of lung cancer, whereas AAT was associated with decreased lung cancer risk in this population. The present study has identified risk haplotypes for CYP1A1 in NSCLC and confirmed that CYP1A1 polymorphisms are a minor risk factor for NSCLC.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/genética , Citocromo P-450 CYP1A1/genética , Estudios de Asociación Genética , Haplotipos/genética , Neoplasias Pulmonares/genética , Polimorfismo Genético , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo , Adulto JovenRESUMEN
Tumour, node, metastasis staging is essential for lung cancer management. However, similarly staged cancers may have markedly different prognoses, indicating that stage cannot completely explain tumour behaviour. While ipsilateral hilar node involvement is designated N1, the current authors hypothesised that primary tumours involving nodes by direct extension are biologically distinct from those involving nodes through lymphatic metastasis. Microarrays were used to investigate the gene expression profiles of 59 primary lung squamous cell carcinomas, comparing N0 tumours (n = 35), N1 tumours by direct extension (N1d; n = 8), and N1/N2 tumours by lymphatic metastasis (N1/N2m; n = 16). Hierarchical clustering using 125 genes differentially expressed between N0 and N1/N2m tumours found N1d tumours clustered with N0 tumours. Class prediction modelling found the expression profiles of all eight N1d tumours were more similar to N0 than to N1/N2m tumours. The present study demonstrates for the first time that N1 tumours directly invading hilar nodes are genomically different to those that metastasise via lymphatics. Independent reports suggest that tumours with direct, rather than metastatic node involvement have better outcomes. Consequently, the data suggest that there is a need to re-evaluate the N1 staging definition in lung cancer. This is relevant for prognosis prediction and also for clinical management, particularly in selecting those patients most likely to benefit from adjuvant chemotherapy.
Asunto(s)
Carcinoma de Células Escamosas/genética , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Neoplasias Pulmonares/genética , Metástasis Linfática , Anciano , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patología , Análisis por Conglomerados , Femenino , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Ganglios Linfáticos/patología , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Análisis de Secuencia por Matrices de Oligonucleótidos , Factores de TiempoRESUMEN
BACKGROUND AND OBJECTIVE: Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most widely prescribed drugs, and their use can be complicated by the development of adverse drug reactions (ADRs). The aim of this study was to assess the frequency of NSAID-induced ADRs in hospitalised patients in the Clinical Divisions of the Catanzaro and Cosenza hospitals. METHODS: We retrospectively analysed NSAID-induced ADRs after evaluating all ADRs recorded by the Clinical Divisions of the Catanzaro and Cosenza hospitals over a 10-year period, from January 1995 to December 2004. RESULTS: NSAIDs were found to be responsible for 55.2% of the episodes of ADRs overall. Diclofenac and aspirin (acetylsalicylic acid) were the drugs most frequently involved in the development of ADRs, while the skin was the body system most susceptible to NSAID-induced ADRs (43%). We determined that the drug-ADR relationship was probable in 62% of the reports; withdrawal of NSAID therapy led to a resolution of the clinical features of ADRs in 86% of episodes. CONCLUSION: NSAID therapy represents a common cause of ADRs in hospitalised patients. Their use should be carefully considered, especially in the presence of polydrug therapy.
Asunto(s)
Antiinflamatorios no Esteroideos/efectos adversos , Adolescente , Adulto , Anciano , Niño , Preescolar , Femenino , Hospitalización/estadística & datos numéricos , Humanos , Lactante , Recién Nacido , Italia , Masculino , Persona de Mediana Edad , Vigilancia de Productos ComercializadosRESUMEN
Due to its efficiency and low capital demands, chlorination has been widely used for disinfection in many wastewater treatment plants. Since the oxidation power of free chlorine is bigger than combined chlorines which are formed from the reaction between chlorine and reducing agents in water (especially, NH4+ and organic nitrogen), for effective disinfection, excess amount of chlorine is added until all the reducing agents are oxidized and free chlorine is available. After chlorination, chlorine residues in wastewater are usually reduced with SO2 or sulfites before the treated wastewater is discharged, since they are toxic to aquatic life. Addition of excess amount of SO2 or sulfite should be avoided. Otherwise, they consume dissolved oxygen in a river or stream and may have adverse impact on the aquatic life. Determination of wastewater chlorine demand and of sulfite dosages for dechlorination has been a challenge to WWTP operators, due to the dynamic characteristics of wastewater. Recently, a new ORP/pH based approach to determine chlorine demand and sulfite dosage was proposed. The method utilizes significant points occurring on the pH and ORP profiles during chlorination and dechlorination titrations. In this study, the proposed automatic titration system has been implemented into a control system to optimize chlorine and sulfite doses for a pilot scale chlorination/dechlorination system. In short, the disinfection system with the pH/ORP based controller showed very successful results; complete inactivation of total coliforms, and almost zero residual chlorines and high DO in its effluent.
Asunto(s)
Cloro/química , Aguas del Alcantarillado , Eliminación de Residuos Líquidos/métodos , Purificación del Agua/métodos , Cloraminas/química , Compuestos de Cloro/química , Desinfectantes , Desinfección , Concentración de Iones de Hidrógeno , Sulfitos , Factores de Tiempo , Contaminantes Químicos del Agua/análisisRESUMEN
Due to its efficiency and relatively low capital demanding, many wastewater treatment plants have applied chlorination for disinfection of treated wastewater before discharging it. However, determination of optimal doses of chlorine for chlorination and sulfite for dechlorination, which removes residual chlorine, should made to guarantee complete destruction of microorganisms in treated wastewater and to protect aquatic life in a receiving stream. In this study, a new ORP/pH based approach to determine endpoints of breakpoint chlorination and of dechlorinating titration and to optimize doses of chlorine and sulfite. In this new method, significant points on the ORP and pH profiles occurring during the titrations for chlorination and dechlorination were utilized to determine chlorine demand and sulfite dosage.
Asunto(s)
Cloro/química , Eliminación de Residuos Líquidos/métodos , Desinfectantes/química , Concentración de Iones de Hidrógeno , Oxidación-Reducción , Sulfitos/química , Purificación del AguaRESUMEN
Non-small cell lung cancer (NSCLC) is the leading cause of cancer death in the world. Traditional chemotherapy for advanced NSCLC is often considered excessively toxic. Recent clinical trials documented that gemcitabine may represent a good therapeutical option in patients with NSCLC. Aim of our research was to retrospectively evaluate the adverse effects induced by gemcitabine in patients with NSCLC from 1 January 1997 to 31 December 2002, in clinical records of Oncology Divisions of "S. Giovanni di Dio" Hospital of Crotone, "Ospedali Riuniti" Hospital of Reggio Calabria, Hospital of Paola, and in Pneumological Oncology Division of "Mariano Santo" Hospital of Cosenza, Italy. Clinical records of patients treated with gemcitabine (1000mgm(-2) on days 1 and 8) were reviewed and following data were obtained: sex and age of the patients, histologic diagnosis and disease stage, World Health Organisation (WHO) performance status and toxic effects induced by gemcitabine. We reported that 71.6% of NSCLC patients (age range 48-77 years; 135 males, 27 females; performance status 0=53, 1=109) were eligible for our study. Side effect of gemcitabine involved gastrointestinal system (nausea, vomiting and diarrhoea) and only in the last cycles (VIII-XI) emopoiethic system (leukopenia, neutropenia, thrombocytopenia and anemia). Grade IV vomiting occurred in three patients, thrombocytopenia in two. Grade III leukopenia was observed in three patients. Other toxicities were mild. None of the patients died during chemotherapy. In conclusion, these data showed that gemcitabine present a very good tolerability in patients with NSCLC. Therefore, it could be considered as a new therapeutic agents to use as first line therapy for this disease.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Desoxicitidina/análogos & derivados , Desoxicitidina/efectos adversos , Neoplasias Pulmonares/tratamiento farmacológico , Anciano , Carcinoma de Pulmón de Células no Pequeñas/sangre , Distribución de Chi-Cuadrado , Desoxicitidina/uso terapéutico , Femenino , Humanos , Neoplasias Pulmonares/sangre , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , GemcitabinaRESUMEN
We retrospectively analysed the adverse drug reactions (ADRs) associated with bronchodilator therapy and reported over a 7-year period, from January 1995 to December 2001, in clinical notes of two Pulmonary division of "Mater Domini" University Hospital and "Pugliese-Ciaccio" Hospital, both located in Catanzaro, Italy. Bronchodilators were responsible for 45 (18.5%) out of 243 episodes of ADRs. Theophylline was the drug most involved in ADRs (53.4%), and skin was the body system most susceptible to ADRs induced by all bronchodilators (47.7%). We determined that the drug-ADR relationship was certain in 73% of the reports; withdrawal of the suspected drug led to recovery in 86% of cases. In conclusion, this retrospective evaluation demonstrated that bronchodilators are a common cause of ADRs in hospitalised patients and, therefore, drug surveillance can successfully identify adverse events related with drug administration in hospitalised patients.
Asunto(s)
Albuterol/análogos & derivados , Broncodilatadores/efectos adversos , Enfermedades Pulmonares/tratamiento farmacológico , Administración por Inhalación , Adolescente , Adulto , Anciano , Albuterol/efectos adversos , Beclometasona/efectos adversos , Broncodilatadores/uso terapéutico , Niño , Preescolar , Etanolaminas/efectos adversos , Femenino , Fumarato de Formoterol , Hospitalización , Humanos , Lactante , Italia , Modelos Logísticos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Xinafoato de Salmeterol , Teofilina/efectos adversosRESUMEN
We retrospectively analysed adverse drug reactions (ADRs) associated with antibiotic therapy and reported over a 6-year period, from January 1995 to December 2000, in clinical notes of two Pulmonology Units of "Mater Domini" University Hospital and "Pugliese-Ciaccio" Hospital, both located in Catanzaro, Italy. Antibiotics were responsible for 92 (44.9%) out of 205 episodes of ADRs. In particular, 22 episodes (23.9%) were observed after penicillin G administration, 19 episodes (20.7%) following ceftazidime and cefotaxime administration, 16 episodes (17.4%) after therapy with ampicillin, and 35 reactions (38%) were further reported during treatments with other antibiotics. We determined that the drug-ADR relationship was certain in 63% of the reports; withdrawal of the suspected drug led to recovery in 95% of cases. In conclusion, this retrospective evaluation demonstrated that antibiotics are a common cause of ADRs in hospitalised patients and, therefore, drug surveillance can successfully identify targeted adverse events.
Asunto(s)
Sistemas de Registro de Reacción Adversa a Medicamentos , Antibacterianos/efectos adversos , Hospitales Universitarios , Enfermedades Respiratorias/tratamiento farmacológico , Adolescente , Adulto , Anciano , Antibacterianos/uso terapéutico , Niño , Preescolar , Utilización de Medicamentos , Femenino , Humanos , Lactante , Recién Nacido , Italia , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
Wild-type Dictyostelium amoebae secrete an autocrine, prestarvation factor (PSF) that allows them to measure the amount of food bacteria compared to their cell density. When the ratio of PSF to bacteria reaches a threshold, the cells are signaled to prepare for eventual starvation. This prestarvation response (PSR) usually starts three to four generations before the end of exponential growth, leading to the accumulation of several aggregation specific genes during growth. We characterize a nystatin-resistant mutant, HK19, that expresses the PSR genes three generations earlier than wild type but has an otherwise wild-type PSR. Although HK19 has a full PSR during growth, HK19 continues to grow at the wild-type rate and reaches normal cell densities. Because HK19 temporally separates the PSR from starvation, it became possible to test whether starvation is required for development. Since HK19 growing at low density can be induced to clump with either cAMP or folate, it appears that the PSR and an external signal are sufficient for entry into development. These data suggest that the PSR is a complex genetic pathway that induces genes involved in the exit from growth and the entry into development.
Asunto(s)
Factores Biológicos/metabolismo , Dictyostelium/crecimiento & desarrollo , Dictyostelium/genética , Regulación de la Expresión Génica , Lectinas , Animales , Antifúngicos/farmacología , AMP Cíclico/metabolismo , AMP Cíclico/farmacología , Dictyostelium/efectos de los fármacos , Discoidinas , Ácido Fólico/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Manosidasas/efectos de los fármacos , Manosidasas/metabolismo , Mutación , Nistatina/farmacología , Proteínas Protozoarias/genética , Proteínas Protozoarias/metabolismo , Inanición , alfa-ManosidasaRESUMEN
Subdural haematoma (SDH) is a known complication of bone marrow transplantation (BMT). A retrospective review of 657 consecutive patients undergoing allogeneic or autologous bone marrow/stem cell transplantation at the Royal Brisbane Hospital between January 1991 and December 1998 is reported. Seventeen cases of subdural haematoma/hygroma were identified (2.6%). Eleven of these (65%) were bilateral. Four required surgical drainage, with two developing re-accumulation of SDH. All cases presented with a headache and eight of these had associated neurological complications. Diagnosis was made predominately by CT scan: however in 25% of cases definitive diagnosis could only be made in MRI studies. An association with intrathecal methorexate-containing conditioning therapy, post lumbar puncture headache, prolonged thrombocytopenia and coagulopathy was noted. In our experience, conservative management with platelet support and correction of coagulopathy achieved resolution of subdural haematoma in most cases, with surgical intervention being reserved for neurological deterioration. Bone Marrow Transplantation (2000) 25, 549-552.
Asunto(s)
Trasplante de Médula Ósea/efectos adversos , Hematoma Subdural/diagnóstico , Hematoma Subdural/terapia , Adolescente , Adulto , Anticoagulantes/uso terapéutico , Anticoagulantes/toxicidad , Niño , Preescolar , Femenino , Cefalea , Hematoma Subdural/etiología , Trasplante de Células Madre Hematopoyéticas/efectos adversos , Humanos , Imagen por Resonancia Magnética , Masculino , Metotrexato/uso terapéutico , Metotrexato/toxicidad , Persona de Mediana Edad , Recuento de Plaquetas , Estudios Retrospectivos , Efusión Subdural/diagnóstico , Efusión Subdural/etiología , Efusión Subdural/terapia , Tomografía , Acondicionamiento Pretrasplante/efectos adversosRESUMEN
In less than a decade, Magnetic Resonance Imaging (MRI) has become the examination of choice in patients with suspected multiple sclerosis (MS). It is the best paraclinical test in assessing dissemination in space of lesions. With serial MRI scans, even dissemination in time can be detected. Using serial Gd-DTPA-enhanced MRI scans, the evolution of lesion can be easily followed. MRI studies in MS patients have contributed to shape current ideas about the pathogenesis of the disease showing that focal breakdown of the blood-brain barrier (BBB) is an early event, if not the first, in the evolution of MS lesions. A number of asymptomatic lesions can be detected by MRI in MS patients, suggesting an ongoing disease activity independent of the clinical appearance. Thus, besides its diagnostic usefulness, MRI will represent the best tool to evaluate effectiveness of treatments in therapeutical trials in MS.
Asunto(s)
Encéfalo/patología , Imagen por Resonancia Magnética , Esclerosis Múltiple/diagnóstico , Diagnóstico Diferencial , Gadolinio DTPA , Humanos , Compuestos Organometálicos , Ácido Pentético/análogos & derivados , Médula Espinal/patologíaRESUMEN
A total of 110 nonmenopausal women (mean age 42.1 years) presenting with symptomatic uterine leiomyomata and/or fibromatous uteri have been enrolled in this trial to evaluate the efficacy of the depot formulation of leuprorelin acetate in decreasing uterine volume and minimizing menorrhagia, dysmenorrhoea and pressure over the bladder. All patients were treated with an intramuscular injection of leuprorelin acetate depot 3.75 mg every 4 weeks for 16 weeks. Clinical examinations and hormonal and ultrasound determinations were performed before, during and at the end of treatment. Appropriate follow-up is still ongoing for most patients. At the end of the treatment period, of 88 women with enlarged fibromatous uteri, 33 (37.5%) showed a decrease in uterine volume of greater than or equal to 50% of the original size, while nine (10.2%) remained with unchanged uterine volume. Of 80 fibromas measurable separately, 47 (52.8%) decreased by greater than 50% of the initial volume and 16 (18%) remained unchanged or even increased. During treatment, clinically advantageous effects were observed in the associated symptomatology, mainly in the production of amenorrhoea and restoration of normal haemoglobin levels. Most of the patients were affected by irregular menstrual blood loss with consequent anaemia that in 29 patients was expressed by low levels of haemoglobin (mean 9.2 g/dl; SD 1.5; range 4.5-11.8 g/dl). By the end of the treatment, only one patient still had moderate vaginal blood loss. Haemoglobin levels rose to a mean value of 11.8 g/dl (SD 1.3; range 8.5-14.1 g/dl). Three patients (2.7%) failed to complete the 16-week treatment protocol, because of headache (one patient) and increased blood pressure (two patients). As a result of the treatment, of the 107 patients who were candidates for surgery and who were included in this study, only nine (8.4%) required surgery during leuprorelin acetate treatment. Of these, four operations were vaginal excision of the submucous myomata protruding into the cervix during treatment, and in five hysterectomy performed because of persistence of symptoms. In most patients the achievement of amenorrhoea minimized the fear of surgical emergency, facilitating an increased awareness of their clinical condition. With the exception of the three patients who dropped out, side effects were mild in all patients, consisting mainly of hot flushes, which were easily tolerated. In the following 8-12 months, the regrowth of uterine volume to original size has been usual in most of the 82 patients now in follow-up.(ABSTRACT TRUNCATED AT 400 WORDS)
Asunto(s)
Leiomioma/tratamiento farmacológico , Leuprolida/uso terapéutico , Neoplasias Uterinas/tratamiento farmacológico , Adulto , Preparaciones de Acción Retardada , Femenino , Estudios de Seguimiento , Humanos , Inyecciones Intramusculares , Italia , Leiomioma/patología , Neoplasias Uterinas/patología , Útero/patologíaRESUMEN
A case of polyorchism is described and the literature reviewed, highlighting the rarity of this pathological condition. To our knowledge, only 70 cases have been reported in the world literature. Similarly, Nocks' embryological development theory is discussed herein. The present case was diagnosed intraoperatively. No further studies were warranted since the intraoperative findings were compatible with a more common pathological condition. Furthermore, the malformation was asymptomatic and was not associated with any other scrotal conditions, unlike most of the cases described in the literature. We discuss the therapeutic approach and underscore the need to remove the supernumerary testis encountered intraoperatively when the continuity of the seminal duct is uncompromised.
Asunto(s)
Testículo/anomalías , Adolescente , Humanos , MasculinoRESUMEN
Tritiated rifaximin was administered in a single oral dose of 10 mg/kg (specific activity 8.998 microCi/mg) and 100 mg/kg (specific activity 0.786 microCi/mg) to rats. After treatment, at fixed times, the animals were sacrificed and the radioactivity in plasma, urine, feces, and in the principal organs and tissues was measured. The radioactivity present in the feces of the two groups of rats was more than 95% of the administered dose, while the amounts found in the urine ranged between 1.15% and 1.5% of the dose. In the plasma and tissues the radioactivity levels were very low. This evidence confirmed the scanty gastroenteric absorption of L/105. Furthermore, as the radioactivity levels maintained almost the same value during the trial, there was the possibility that the amounts found were in part due to isotopic exchange between tritium of 3H-L/105 and hydrogen of water.