RESUMO
PURPOSE: The increasing share of older adults is associated with heavier Emergency Health Services utilization. In this context, a significant problem is the rate of unplanned revisits of geriatric patients after discharge from the Emergency Department (ED). We aimed to evaluate whether the referral to a dedicated Geriatric Revaluation Clinic (GRC) after discharge from the ED is associated with fewer early unplanned returns. METHODS: We conducted an observational, retrospective, case-control study comparing patients 65 years or older evaluated in a GRC after an ED visit and a control group of same age subjects accessing the ED during the study period and discharged with one of the ICD-9-CM diagnoses used for the cases, for whom defined post-ED assessment was not arranged. The intervention at the GRC consisted of a comprehensive geriatric evaluation. We calculated unadjusted and adjusted OR for unplanned ED revisits within 30 days from ED discharge using two logistic regression models including the variables with statistically significant differences among study groups at univariate analysis. RESULTS: During the study period, 121 eligible patients were evaluated at the GRC and were matched to 242 subjects included in the control group. The median age of the study population was 85 years. The adjusted OR for unplanned return after ED discharge and unplanned hospital admission after ED discharge were 0.44 (CI 0.20-0.89) and 0.52 (CI 95% 0.18-1.74), respectively. CONCLUSIONS: In a population of older patients discharged from the ED, the referral to a GRC is associated with fewer early unplanned revisits.
Assuntos
Serviço Hospitalar de Emergência , Hospitalização , Humanos , Idoso , Idoso de 80 Anos ou mais , Estudos Retrospectivos , Estudos de Casos e Controles , Alta do PacienteRESUMO
From a biological point of view, aging can be considered a progressive inability of an organism to react to stress, maintain homeostasis, and survive unfavourable changes during post-maturational life. The expression of several adipokines changes during aging and for some changes, a role in the onset of chronic disease and frailty has been proposed. Among adipokines, resistin was shown in recent studies to play a key role in aging. Resistin is a small secreted protein that regulates glucose metabolism in mammalians. High resistin levels induce insulin resistance and exert proinflammatory effects. Consistently, resistin has been shown to play a pivotal role in various metabolic, inflammatory, and autoimmune diseases. Herein, the role of resistin as a molecular link between aging and age-related conditions was reviewed and the clinical implications of this knowledge discussed.
Assuntos
Envelhecimento , Resistina , Idoso , Envelhecimento/genética , Envelhecimento/imunologia , Envelhecimento/metabolismo , Animais , Doenças Cardiovasculares/mortalidade , Doenças Cardiovasculares/fisiopatologia , Doenças do Sistema Nervoso Central/fisiopatologia , Doença Crônica , Glucose/metabolismo , Humanos , Inflamação/genética , Inflamação/metabolismo , Resistência à Insulina/fisiologia , Transtornos Mentais/fisiopatologia , Camundongos , Pessoa de Meia-Idade , Doenças Musculoesqueléticas/fisiopatologia , Obesidade/fisiopatologia , Resistina/genética , Resistina/imunologia , Resistina/metabolismoRESUMO
The present study aimed to evaluate the effects of two types of 9-month adapted physical activity (APA) program, based on a muscle reinforcement training and a postural training, respectively, on muscle mass, muscle strength, and static balance in moderate sarcopenic older women. The diagnosis of sarcopenia was done in accordance with measurable variables and cut-off points suggested by the European Working Group on Sarcopenia in Older People (EWGSOP). Seventy-two participants were randomly assigned to two groups: the muscle reinforcement training group (RESISTANCE) (n=35; 69.9 ± 2.7 years) and the postural training group (POSTURAL) (n=37; 70.0±2.8 years). Body composition, muscle mass, skeletal muscle mass index (SMI), and handgrip strength (HGS) were evaluated for sarcopenia assessment, whereas Sway Path, Sway Area, Stay Time, and Spatial Distance were evaluated for static balance assessment. Sixty-six participants completed the study (RESISTANCE group: n=33; POSTURAL group: n=33). Significant increases of muscle mass, SMI, and handgrip strength values were found in the RESISTANCE group, after muscle reinforcement program. No significant differences appeared in the POSTURAL group, after postural training. Furthermore, RESISTANCE group showed significant improvements in static balance parameters, whereas no significant differences appeared in the POSTURAL group. On the whole, the results of this study suggest that the APA program based on muscle reinforcement applied on moderate sarcopenic older women was able to significantly improve muscle mass and muscle strength, and it was also more effective than the applied postural protocol in determining positive effects on static balance.
Assuntos
Terapia por Exercício , Força Muscular/fisiologia , Equilíbrio Postural/fisiologia , Treinamento Resistido , Sarcopenia/terapia , Idoso , Exercício Físico/fisiologia , Feminino , Força da Mão/fisiologia , Humanos , Músculo Esquelético/fisiologia , Sarcopenia/fisiopatologiaRESUMO
OBJECTIVE: The aim of the present study was to validate the photographic indirect method as an accurate and specific tool to assess nutritional intake in a cohort of elderly hospitalized patients. DESIGN: this is a prospective observational study. SETTING: hospital (geriatric acute ward and transitional care of IRCCSS AUO San Martino Hospital, Genoa, Italy). PARTICIPANTS: 255 consecutive elderly hospitalized patients. MEASUREMENTS: assessment of malnutrition by: Mini nutritional assessment (MNA) and abbreviated Comprehensive geriatric assessment (CIRS; Barthel index, SPMSE). The direct method (Gold standard): food dish weight (before lunch) and residual (after lunch) food dish weight and estimation of the percentage of eaten food and of residual food for each dish. The percentages of food intake and residual food were calculated according to the following formula: intake %= initial weight of the dishes- residual food weight)/ initial weight dish x100. The unit of variable was the percentage. The indirect photographic method with extrapolation of the lunch food intake by photographic method confronting initial meal and residual meal (25% quartile food dish estimation). RESULTS: The results showed a significant correlation between the direct method (weighing residual food) and the indirect photographic method(n=255; r=0.9735; p<0.001) as well as a significant positive correlation between the indirect photographic method and the food caloric estimation calculated by the direct method (n=255; r= 0.6489, p<0.001). Intraclass coefficient (ICC), showed a highly significant degree of agreement between the gold standard and the indirect photographic method (ICC: 0.69; p<0.0001). Additionally, the results showed a good inter rater agreement of the indirect photographic method (kappa-statistic measure of interrater agreement: (Z=13.04; p<0.001); agreement 70.29% e Kappa=0.5965) and a good specificity of the indirect method as it was independent on the single food item. CONCLUSIONS: The study originally provided the validation of the indirect photographic method for the assessment of nutritional intake in a vast cohort of hospitalized elderly subjects. The present results moved a step forward in the appropriate assessment of nutrition intake in frail elderly, providing an easy to use tool that may be incorporate in routine clinical practice for early and targeted therapeutic interventions.
Assuntos
Ingestão de Alimentos , Ingestão de Energia , Avaliação Geriátrica/métodos , Hospitalização , Desnutrição/diagnóstico , Avaliação Nutricional , Fotografação , Idoso , Idoso de 80 Anos ou mais , Feminino , Alimentos , Idoso Fragilizado , Humanos , Itália , Masculino , Estado Nutricional , Estudos Prospectivos , Reprodutibilidade dos TestesRESUMO
AIMS: The Belgian case of a 24 years' woman affected by resistant depression, who obtained the legal right to assisted suicide rehearsed ethical issues. From the famous Chabot case of the Dutch court in 1994, accumulating legal evidence indicates that the unbearable psychiatric suffering may be equate to the physical struggle of end of life patients. The Belgian law has addressed assisted suicide as an option in case of unbearable psychic suffering with no future prospective. DESIGN: It is unlikely that the practice of euthanasia may be mechanistically reduced to the provision of a suicide as alleviating the burden of suffering in depression is a long life commitment; moreover, the principle of patient's self determination and autonomy is highly debatable: the closure to the future, the hopelessness and the suicidal ideation represent per se core features of depression. Might they be discriminated as non pathological in assessing patients' competence and how? DISCUSSION: The slippery slopes is even more upsetting when dealing with elderly affected by chronic disability. Some body of evidence justified suicide in elderly as the final auto determination to preserve the person's dignity, and quality of life. The growing scenario of economic shortages in heath care system seems to further legalize the social prejudice and the ageistic discrimination towards elderly with disability. The silver tsunami will face the challenge of true self determination; will it be acted through assisted suicide or through a rebuilding of western heath care policies to fulfill the emergent needs of an aging population?
Assuntos
Depressão , Suicídio Assistido , Idoso , Depressão/psicologia , Feminino , Humanos , Autonomia Pessoal , Qualidade de VidaRESUMO
Osteoporosis is a metabolic multifaceted disorder, characterized by insufficient bone strength. It has been recently shown that advanced glycation end products (AGEs) play a role in senile osteoporosis, through bone cell impairment and altered biomechanical properties. Pentosidine (PENT), a wellcharacterized AGE, is also considered a biomarker of bone fracture. Adequate responses to various hormones, such as 1,25-dihydroxyvitamin D3, are prerequisites for optimal osteoblasts functioning. Vitamin K2 is known to enhance in vitro and in vitro vitamin D-induced bone formation. The aim of the study was to assess the effects of Vitamins D3 and K2 and PENT on in vitro osteoblast activity, to convey a possible translational clinical message. Ex vivo human osteoblasts cultured, for 3 weeks, with vitamin D3 and vitamin K2 were exposed to PENT, a well-known advanced glycoxidation end product for the last 72 hours. Experiments with PENT alone were also carried out. Gene expression of specific markers of bone osteoblast maturation [alkaline phosphatase, ALP; collagen I, COL Iα1; and osteocalcin (bone-Gla-protein) BGP] was measured, together with the receptor activator of nuclear factor kappa-B ligand/osteoproteregin (RANKL/OPG) ratio to assess bone remodeling. Expression of RAGE, a well-characterized receptor of AGEs, was also assessed. PENT+vitamins slightly inhibited ALP secretion while not affecting gene expression, indicating hampered osteoblast functional activity. PENT+vitamins up-regulated collagen gene expression, while protein secretion was unchanged. Intracellular collagen levels were partially decreased, and a significant reduction in BGP gene expression and intracellular protein concentration were both reported after PENT exposure. The RANKL/OPG ratio was increased, favouring bone reabsorption. RAGE gene expression significantly decreased. These results were confirmed by a lower mineralization rate. We provided in vitro evidence that glycoxidation might interfere with the maturation of osteoblasts, leading to morphological modifications, cellular malfunctioning, and inhibition of the calcification process. However, these processes may be all partially counterbalanced by vitamins D3 and K2. Therefore, detrimental AGE accumulation in bone might be attenuated and/or reversed by the presence or supplementation of vitamins D3 and K2.
Assuntos
Arginina/análogos & derivados , Colecalciferol/farmacologia , Lisina/análogos & derivados , Osteoblastos/efeitos dos fármacos , Vitamina K 2/farmacologia , Fosfatase Alcalina/biossíntese , Fosfatase Alcalina/genética , Antígenos de Neoplasias/biossíntese , Antígenos de Neoplasias/genética , Arginina/antagonistas & inibidores , Arginina/toxicidade , Remodelação Óssea/efeitos dos fármacos , Células Cultivadas , Colágeno Tipo I/biossíntese , Colágeno Tipo I/genética , Cadeia alfa 1 do Colágeno Tipo I , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Lisina/antagonistas & inibidores , Lisina/toxicidade , Proteínas Quinases Ativadas por Mitógeno/biossíntese , Proteínas Quinases Ativadas por Mitógeno/genética , Osteoblastos/metabolismo , Osteocalcina/biossíntese , Osteocalcina/genética , Osteogênese/efeitos dos fármacos , Osteoprotegerina/biossíntese , Osteoprotegerina/genética , Ligante RANK/biossíntese , Ligante RANK/genética , RNA Mensageiro/biossíntese , RNA Mensageiro/genéticaRESUMO
Cachexia, the most severe paraneoplastic syndrome, occurs in about 80% of patients with advanced cancer; it cannot be reverted by conventional, enteral, or parenteral nutrition. For this reason, nutritional interventions must be based on the use of substances possessing, alongside nutritional and energetic properties, the ability to modulate production of the pro-inflammatory factors responsible for the metabolic changes characterising cancer cachexia. In light of their nutritional and anti-inflammatory properties, polyunsaturated fatty acids (PUFAs), and in particular n-3, have been investigated for treating cachexia; however, the results have been contradictory. Since both n-3 and n-6 PUFAs can affect cell functions in several ways, this research investigated the possibility that the effects of both n-3 and n-6 PUFAs could be mediated by their major aldehydic products of lipid peroxidation, 4-hydroxyhexenal (HHE) and 4-hydroxynonenal (HNE), and by their anti-inflammatory properties. An "in vitro" cancer cachexia model, consisting of human lung cancer cells (A427) and murine myoblasts (C2C12), was used. The results showed that: 1) both n-3 and n-6 PUFAs reduced the growth of lung cancer cells without causing cell death, increased lipid peroxidation and Peroxisome Proliferator-Activated Receptor (PPAR)α, and decreased TNFα; 2) culture medium conditioned by A427 cells grown in the absence of PUFAs blocked myosin production and the differentiation of C2C12 muscle cells; conversely, muscle cells grown in culture medium conditioned by the same cells in the presence of PUFAs showed myosin expression and formed myotubes; 3) adding HHE or HNE directly to C2C12 cells maintained in culture medium conditioned by A427 cells in the absence of PUFAs stimulated myosin production and myotube formation; 4) putative consensus sequences for (PPARs) have been found in genes encoding fast isoforms of myosin heavy chain, by a bioinformatics approach. The overall results show, first, the ability of both n-3 and n-6 PUFAs and their lipid peroxidation products to prevent the blocking of myosin expression and myotube formation caused in C2C12 cells by medium conditioned by human lung tumour cells. The C2C12 cell differentiation can be due to direct effect of lipid peroxidation products, as evidenced by treating C2C12 cells with HHE and HNE, and to the decrease of pro-inflammatory TNFα in A427 cell culture medium. The presence of consensus sequences for PPARs in genes encoding the fast isoforms of myosin heavy chain suggests that the effects of PUFAs, HHE, and HNE are PPAR-mediated.
Assuntos
Aldeídos/farmacologia , Ácidos Docosa-Hexaenoicos/farmacologia , Ácido Eicosapentaenoico/farmacologia , Cadeias Pesadas de Miosina/metabolismo , PPAR alfa/metabolismo , Mucosa Respiratória/efeitos dos fármacos , Aldeídos/metabolismo , Animais , Sítios de Ligação , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Meios de Cultivo Condicionados/farmacologia , Regulação da Expressão Gênica , Humanos , Peroxidação de Lipídeos , Camundongos , Células Musculares/citologia , Células Musculares/efeitos dos fármacos , Células Musculares/metabolismo , Cadeias Pesadas de Miosina/genética , PPAR alfa/genética , Ligação Proteica , Mucosa Respiratória/metabolismo , Mucosa Respiratória/patologia , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Persistent pain in the elderly with dementia is neglected and effective pain diagnostic tools still lack. The aim of the study was to re-assess pain after 1 year in a group of elderly with dementia, resident in a Nursing Home. Doloplus-2 scale was adopted to detect pain and to evaluate its adequacy to address analgesia. Thirty-six out of 90 residents were affected by moderate-severe dementia and 23 patients with persistent pain were enrolled in the study. The results showed a significant reduction of Doloplus-2 score in the observational period (p <0.001) and of its mean score below the pain threshold (p <0.0001). This case analysis confirmed the clinical utility of Doloplus-2 to detect pain in patients with very advanced age and with severe dementia. The tool also confirmed its handiness and clinical applicability by nurses in order to support a systematic pain assessment in long term care.
Assuntos
Demência/enfermagem , Idoso Fragilizado , Avaliação Geriátrica , Medição da Dor/enfermagem , Dor/enfermagem , Idoso de 80 Anos ou mais , Demência/diagnóstico , Feminino , Avaliação Geriátrica/métodos , Instituição de Longa Permanência para Idosos , Humanos , Masculino , Casas de Saúde , Dor/diagnóstico , Reprodutibilidade dos TestesRESUMO
Matrix metalloproteinases (MMPs), their inhibitors (TIMPs) and inflammatory cytokines, such as interleukin-1 (IL-1), are considered markers of evolution and/or instability of atherosclerotic plaques. Accumulation of Advanced Glycation Endproducts (AGE) is a well known phenomenon in diabetes and has also been considered in the pathogenesis of atherosclerosis. Aim of the present study was to analyse the levels of pentosidine, a fluorescent AGE, and to evaluate the expression of MMP-2, TIMP-3, and IL-1 in an ex vivo model of human advanced atherosclerotic plaques. We intended to test the possible correlation between pentosidine and markers of ECM remodelling and inflammation in the atherosclerotic process, and to investigate if classic risk factors, such as diabetes and hypertension, influenced these biochemical parameters. We found that diabetic plaques showed higher level of pentosidine, as expected, but much lower, or even undetectable, expression levels of MMP-2 and TIMP-3; IL-1 expression was not different between diabetic and non diabetic plaques. Hypertension did not influence any of these parameters. Although the statistical correlations between the expression of the considered genes and pentosidine did not reach significance, slight negative trends were noted between TIMP-3 and IL-1 expression vs. pentosidine content. We suggest that in mature diabetic plaques AGE accumulation can exert stabilizing effects on matrix proteins, while scanty cell presence leads to poor capacity of reactive responses, such as remodelling and inflammation.
Assuntos
Aterosclerose/fisiopatologia , Angiopatias Diabéticas/fisiopatologia , Produtos Finais de Glicação Avançada/metabolismo , Mediadores da Inflamação/metabolismo , Metaloproteases/metabolismo , Placa Aterosclerótica/metabolismo , Idoso , Arginina/análogos & derivados , Arginina/metabolismo , Aterosclerose/epidemiologia , Aterosclerose/imunologia , Biomarcadores/metabolismo , Artéria Carótida Interna/metabolismo , Estenose das Carótidas/fisiopatologia , Angiopatias Diabéticas/epidemiologia , Angiopatias Diabéticas/imunologia , Angiopatias Diabéticas/metabolismo , Matriz Extracelular/metabolismo , Regulação da Expressão Gênica , Humanos , Interleucina-1alfa/genética , Interleucina-1alfa/metabolismo , Itália/epidemiologia , Lisina/análogos & derivados , Lisina/metabolismo , Metaloproteinase 2 da Matriz/genética , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteases/genética , Placa Aterosclerótica/enzimologia , Placa Aterosclerótica/etiologia , Placa Aterosclerótica/fisiopatologia , Fatores de Risco , Índice de Gravidade de Doença , Inibidor Tecidual de Metaloproteinase-3/genética , Inibidor Tecidual de Metaloproteinase-3/metabolismoRESUMO
The aim of this observational study was to investigate the occurrence of postoperative delirium (POD) in elderly patients undergoing urological surgery and to identify those factors associated with delirium. Ninety consecutive patients (81 males and 9 females; average age of 74.3 ± 0.40 years), undergoing urological surgery in University-Hospital Urological Clinic were selected. Personal, medical, cognitive and functional data, biochemical parameters, preoperative medications, conduct of surgery and anesthesia and details of hemodynamic control were collected as predictors of delirium. After surgery, the subjects were divided on the basis of delirium onset within a week observation period. Delirium was diagnosed by the Confusion Assessment Method. Delirium started the first post-operative day (2F; 6 M) and lasted 3.0 ± 0.8 days. Subjects with POD were significantly older, had a previous history of delirium, were more impaired in the instrumental activities of daily living and had poorer clock drawing test (CDT) score. Interestingly, a significantly greater number of hypotensive events were recorded during anesthesia. Age, cognitive and functional status, previous history of delirium and hypotensive episodes intrasurgery are the best predictor of POD in this setting. Our findings have implications in preventing delirium in elderly by an early and targeted evaluation.
Assuntos
Envelhecimento , Delírio/epidemiologia , Complicações Pós-Operatórias/epidemiologia , Procedimentos Cirúrgicos Urológicos , Atividades Cotidianas , Idoso , Cognição , Estudos de Coortes , Feminino , Avaliação Geriátrica , Humanos , Hipotensão/complicações , Masculino , Fatores de RiscoRESUMO
Non-verbal pain assessment scales are useful tools for pain evaluation in persons with communication disorders and moderate-severe dementia. The Doloplus was one of the first scales to be developed and validated as a pain assessment tool in older adults with dementia. This study aims at evaluating the translation of the Doloplus scale in five languages, as regards test-retest and inter-rater reliability. Results show that both tests are good or excellent for the English, Italian, Portuguese and Spanish versions and moderate for the Dutch version. These results bring a unique opportunity to include the translated Doloplus scale in daily assessment of elderly persons with communication disorders, and future studies should focus on enriching the validation of the scale in each language.
Assuntos
Demência/complicações , Avaliação Geriátrica , Medição da Dor/normas , Dor/diagnóstico , Idoso , Idoso de 80 Anos ou mais , Humanos , Dor/complicações , Reprodutibilidade dos Testes , Inquéritos e Questionários/normasRESUMO
In Italy, more than 3 million people annually sustain a domestic injury; the elderly experience it the most. From a healthcare perspective, elderly falls are a major clinical issue with an outgrowing socioeconomic burden. The aim of the study was to evaluate the epidemiology of injurious falls in a community dwelling population, admitted to the emergency room (ER) because of a domestic injury, to assess the socioeconomic burden. Seventy-four hospitalized patients among 227 were examined. Falls represented the main cause of admittance to the ER; the average cost for fall-related hospitalization was of 5479.09.
Assuntos
Acidentes por Quedas/estatística & dados numéricos , Acidentes Domésticos/estatística & dados numéricos , Serviço Hospitalar de Emergência/estatística & dados numéricos , Hospitalização/economia , Acidentes por Quedas/economia , Acidentes por Quedas/mortalidade , Acidentes Domésticos/economia , Acidentes Domésticos/mortalidade , Idoso , Idoso de 80 Anos ou mais , Efeitos Psicossociais da Doença , Grupos Diagnósticos Relacionados/economia , Feminino , Idoso Fragilizado/estatística & dados numéricos , Gastos em Saúde/estatística & dados numéricos , Humanos , Itália/epidemiologia , MasculinoRESUMO
Advanced glycation end-products (AGEs), which accumulate in the blood and tissues of patients with chronic renal failure (CRF) undergoing chronic hemodialysis, play an important role in the pathogenesis of uremic complications. Endothelin 1 (ET1), a 21-amino acid peptide with vasoconstricting and mitogenic properties, is an important factor in the endothelial dysfunction occurring in uremia. The circulating levels of both AGEs and ET1 have been reported to be increased in chronic renal failure. In the present study we evaluated the possible relationship between pentosidine and ET1 plasma levels in CRF patients undergoing chronic hemodialysis treatment. The plasma concentrations of "free" and bound pentosidine (HPLC methods) and endothelin-1 (RIA method) were measured before the hemodialysis session in 40 nondiabetic CRF patients (22 males and 18 females; 54+/-3 years) on chronic hemodialysis for at least 1 year. Forty age- and sex-matched normal subjects served as a control group. In hemodialyzed patients, the overall pentosidine residues and pentosidine-free adduct plus pentosidine-free adduct bound reversibly to protein levels (24.9+/-2.04 pmol/mg protein and 110.5+/-5.9 pmol/ml, respectively) were significantly higher than those recorded in normal subjects (2.0+/-0.2 pmol/mg protein and 0.7+/-0.2 pmol/ml, respectively ). Endothelin-1 was also significantly (p<0.01) increased in CRF patients (10.6+/-0.4 pmol/ml in CRF patients and 2.7+/-0.3 pmol/ml in normal subjects). A significant positive correlation (p<0.01) was seen between "total" pentosidine (pentosidine residues and pentosidine-free adduct plus pentosidine-free adduct bound reversibly to protein) levels and endothelin-1 plasma values. The correlation between pentosidine and endothelin-1 provides further evidence that some AGEs exert a detrimental effect on the vascular endothelium, thereby contributing to the hypertension and other cardiovascular damage seen in CRF patients.
Assuntos
Arginina/análogos & derivados , Endotelina-1/sangue , Lisina/análogos & derivados , Diálise Renal , Arginina/sangue , Estudos de Casos e Controles , Feminino , Humanos , Falência Renal Crônica/sangue , Lisina/sangue , Masculino , Pessoa de Meia-IdadeRESUMO
A new, simple and fast spectrophotometric method for the determination of the H(2)S concentration is reported. This method, based on the 1:1 reaction between H(2)S and the ferric derivative of hemoglobin I (HbI) from the bivalve mollusc Lucina pectinata, allows the quantitative determination of H(2)S dissolved in a given solution even at concentrations as low as 1 x 10(-6) M. Note that L. pectinata HbI is considered the physiological receptor of H(2)S.