Comparing health care outcomes before and after employing nurse practitioners in cardiovascular hospitals in Japan: A retrospective chart review.

BACKGROUND: There are approximately 872 certified nurse practitioners (NPs) in Japan as of April 2024. However, research on the results of their specific activities is still scarce. PURPOSE: This study aimed to compare health care outcomes before (i.e., 2019) and after (i.e., 2021) employing NPs in cardiovascular hospitals in Japan. METHODOLOGY: We conducted a retrospective chart review and analyzed 114 patients who underwent cardiac surgery in Hospital A and 381 patients who received pacemaker implantation/replacement in Hospital B. Hospital A hired one NP for cardiac surgery service, and Hospital B hired one NP for pacemaker device service. The NPs assisted in the surgical procedures and provided postsurgical management. RESULTS: In Hospital A, the median length of hospitalization and intubation were shorter in 2021 than in 2019 (p = .02 and .01, respectively). In Hospital B, medical fee reimbursement was lower in 2021 (p < .001) than in 2019, and the median procedure duration was shorter (p = .01), which remained statistically significant after controlling for age, comorbidities, and device types. Some outcomes improved following the employment of NPs, whereas others remained unchanged. CONCLUSIONS: Nurse practitioners managed surgical patients well and contributed to the quality care of cardiovascular medicine. IMPLICATIONS: The employment of NPs in Japan is encouraged because even a single NP can have a positive, although not large, impact on patients and organizations.

Adrenal infarction with latent myelodysplastic/myeloproliferative neoplasm, unclassifiable with JAK2V617F mutation.

Key Clinical Message: Hematopoietic neoplasms can cause adrenal infarction. In cases of thrombosis occurring at uncommon sites, it is necessary to consider evaluating for the JAK2V617F mutation, even in the absence of notable abnormalities in blood counts. Abstract: Adrenal infarction, a rare ailment, has been sporadically linked to hematopoietic neoplasms. A 46-year-old male encountered left adrenal infarction, which coincided with a progressive rise in platelet counts. Subsequent diagnosis revealed myelodysplastic/myeloproliferative neoplasm-unclassifiable, featuring a JAK2V617F mutation. Simultaneously, the patient manifested multiple arteriovenous thromboses, necessitating treatment with edoxaban, aspirin, and hydroxyurea. Following thrombosis resolution, he was transferred to a transplantation center. This report delves into the thrombogenicity linked to the JAK2V617F mutation, while also examining documented instances of adrenal infarction in myeloid neoplasms. We should consider evaluating for JAK2V617F mutation even in cases of thrombosis at unusual sites, including adrenal infarction, even if there are no considerable abnormalities in blood counts.

Hemoglobin-platelet index as a prognostic factor in patients with peripheral T-cell lymphoma.

Peripheral T-cell lymphoma (PTCL) is a heterogeneous group of aggressive lymphomas with a poor prognosis. The International Prognostic Index (IPI) and the Prognostic Index for PTCL-unspecified (PIT) is used to predict the prognosis of PTCL. The hemoglobin-platelet index (HPI), based on anemia and thrombocytopenia status, is associated with the prognosis of diffuse large B-cell lymphoma. However, its significance in terms of predicting the prognosis of PTCL has not been fully investigated. We herein retrospectively analyzed 100 patients with newly diagnosed PTCL in our department. At a median follow-up of 3.2 years, the median progression-free survival (PFS) and overall survival (OS) was 0.72 (95% confidence interval [CI]: 0.56-1.2) years and 2.0 (95% CI: 1.5-4.7) years, respectively. Multivariate analysis revealed that elevated lactic dehydrogenase (LDH) and hypoalbuminemia were independent adverse variables for PFS. The HPI showed significant predictive value for both PFS and OS. As a new prognostic model comprising the HPI, LDH, and albumin, the LA-HPI allowed the stratification of patients into four distinct risk subgroups: low risk (zero risk factors), low-intermediate risk (one risk factors), high-intermediate risk (two or three risk factors), or high risk (four risk factors). The PFS and OS differed significantly among the patients by the LA-HPI score. The LA-HPI demonstrated better predictive performance compared to the IPI, PIT, and HPI. Our data demonstrated the prognostic utility of the HPI in patients with PTCL. The LA-HPI, incorporating four readily obtainable parameters, exhibited superior performance compared to traditional indices.

Focal nodular hyperplasia: our experience of 53 Japanese cases.

PURPOSE: Contrast-enhanced ultrasound (CEUS) is a very sensitive diagnostic tool in characterizing liver tumors. It is especially useful in the diagnosis of focal nodular hyperplasia (FNH) of the liver. According to the previous reports, FNH is common in young women, and it is usually diagnosed by MRI. The majority of the previous reports come from European countries, and a very few studies of large series designed to describe the clinical features in Japanese patients have been reported. The aim of this study was to (a) describe the clinical features in 53 patients (59 lesions) diagnosed with CEUS and (b) compare the data with those from the previous reports. METHODS: The medical data from 53 patients diagnosed on the basis of typical CEUS findings at our institution and affiliated hospitals were reviewed, and their clinical data were analyzed. RESULTS: (1) The medical data from 53 cases showed a slight male predilection, with 30 male cases (57 %) and 23 female cases (43 %), although the occurrence in both sexes was equal. FNH cases were distributed throughout all generations in both sexes, mostly concentrated in the age of 30-60 years old, and metabolic cases were more common in men than in women (4 vs 0). (2) The lesions were small (mean: 23 mm) and distributed throughout the whole liver. (3) Lesion size was not influenced by age in either sex. (4) A rapid draining to the hepatic vein was recognized in five out of 59 lesions (8 %). CONCLUSIONS: Our data indicate that FNH occurs slightly more frequently in men than in women in Japan. It occurs also at any age in both sexes, but the mean lesion size was smaller in our series than in the previous reports. Metabolic disease was seen only in male FNH patients. A direct communication between the FNH lesion and the hepatic vein is diagnostically worth noting.

Evaluation of Interferon Resistance in Newly Established Genotype 1b Hepatitis C Virus Cell Culture System.

BACKGROUND AND AIMS: The hepatitis C virus (HCV) genotype 1b is known to exhibit treatment resistance with respect to interferon (IFN) therapy. Substitution of amino acids 70 and 91 in the core region of the 1b genotype is a significant predictor of liver carcinogenesis and poor response to pegylated-IFN-α and ribavirin therapy. However, the molecular mechanism has not yet been clearly elucidated because of limitations of the HCV genotype 1b infectious model. Recently, the TPF1-M170T HCV genotype 1b cell culture system was established, in which the clone successfully replicates and infects Huh-7-derived Huh7-ALS32.50 cells. Therefore, the purpose of this study was to compare IFN resistance in various HCV clones using this system. METHODS: HCV core amino acid substitutions R70Q and L91M were introduced to the TPF1-M170T clone and then transfected into Huh7-ALS32.50 cells. To evaluate the production of each virus, intracellular HCV core antigens were measured. RESULTS were confirmed with Western blot analysis using anti-NS5A antibodies, and IFN sensitivity was subsequently measured. RESULTS: Each clone was transfected successfully compared with JFH-1, with a significant difference in intracellular HCV core antigen (p < 0.05), an indicator of continuous HCV replication. Among all clones, L91M showed the highest increase in the HCV core antigen and HCV protein. There was no significant resistance against IFN treatment in core substitutions; however, IFN sensitivity was significantly different between the wildtype core and JFH-1 (p < 0.05). CONCLUSIONS: A novel genotype 1b HCV cell culture was constructed with core amino acid substitutions, which demonstrated IFN resistance of genotype 1b. This system will be useful for future analyses into the mechanisms of HCV genotype 1b treatment.

Efficacy of additional radiofrequency ablation after transcatheter arterial chemoembolization for intermediate hepatocellular carcinoma.

AIM: For intermediate hepatocellular carcinoma (HCC), transcatheter arterial chemoembolization (TACE) therapy is recommended in the guidelines as a monotherapy, although TACE is a non-curative therapy. The aims of the present study were to evaluate the efficacy of adding radiofrequency ablation (RFA) to TACE in patients with intermediate HCC, and to identify the factors that were associated with favorable survival in these patients. METHODS: Fifty-nine patients with intermediate HCC were enrolled in this retrospective study. Thirty-nine patients were treated with TACE alone and 20 patients were treated with additional RFA after TACE. RESULTS: The recurrence-free survival rates at 0.5, 1 and 2 years for the additional RFA group were 32%, 19% and 13%, respectively, and these were significantly higher than those of the TACE group (8%, 3% and 0%, respectively; log-rank test, P = 0.001). The cumulative survival rates of the additional RFA group were significantly higher than those of the TACE group (log-rank test, P = 0.002), although this significant difference was not found in the subgroup of treatment naive patients because of small sample size. Multivariate analysis indicated male sex, lower total bilirubin, lower α-fetoprotein, lower des-γ-carboxyprothrombin, newly recurrent HCC nodules within the last 12 months and additional RFA as independent factors that were significantly associated with favorable overall survival. CONCLUSION: Additional RFA of nodules insufficiently treated by TACE is effective therapy for obtaining favorable disease-free survival in patients with intermediate HCC, and leads to better overall survival particularly in recurrent patients.

Comprehensive analyses of mutations and hepatitis B virus integration in hepatocellular carcinoma with clinicopathological features.

BACKGROUND AND AIMS: Genetic alterations in specific genes are critical events in carcinogenesis and hepatocellular carcinoma (HCC) progression. However, the genetic alterations responsible for HCC development, progression, and survival are unclear. METHODS: We investigated the essential difference in genetic alterations between HCC and adjacent non-HCC tissues using next-generation sequencing technology. RESULTS: We found recurrent mutations in several genes such as telomerase reverse transcriptase (TERT; 65% of the total 104 HCCs), TP53 (38%), CTNNB1 (30%), AXIN1 (2%), PTEN (2%), and CDKN2A (2%). TERT promoter mutations were associated with older age (p = 0.005), presence of hepatitis C virus (HCV) infection (p = 0.003), and absence of hepatitis B virus (HBV) infection (p < 0.0001). In hepatitis B surface antigen (HBs Ag)-positive HCC without TERT promoter mutations, HBV integration into TERT locus was found in 47% patients and was mutually exclusive to TERT promoter mutations. Most (89%) HBV integrants were in the HBx region. TP53 mutations were associated with HBV infection (p = 0.0001) and absence of HCV infection (p = 0.002). CTNNB1 mutations were associated with absence of HBV infection (p = 0.010). Moreover, TERT promoter mutation was significantly associated with shorter disease-free survival (p = 0.005) and poor overall survival (p = 0.024). CONCLUSIONS: Gene alterations in TERT promoter, TP53, CTNNB1, and HBV integration were closely associated with HCC development, and mutations in TERT promoter are related to poor prognosis. These results are useful for understanding the underlying mechanism of hepatocarcinogenesis, diagnosis, and predicting outcomes of patients with HCC.

Creation of a questionnaire to measure stress among nurses engaged in palliative care on general wards.

PURPOSE: This study was conducted to create a questionnaire that measures stress among nurses engaged in palliative care on general wards. METHODS: Nurses with at least 3 years of experience involved in palliative care on a general ward in six facilities in Japan were the subjects from September 7 to October 4, 2004. A draft questionnaire on stress factors and conditions of stress in nurses engaged in end-of-life care was created, and question items and content meaning were revised to produce 32 question items, with a four-point Likert scale for the responses. Two pretests were conducted. Internal validity was investigated and resulted in 31 question items. Factor analysis using the principal factor method (Varimax rotation) was performed, and Cronbach's coefficient alpha was used to evaluate internal consistency and check reliability. RESULTS: The survey response rate was 94%, with a valid response rate of 98%. Analysis was conducted using responses from 269 participants, of whom 98.9% were female, with a mean age of 35.4 years. The mean length of experience as a nurse was 13.6 years, and the mean length of experience in cancer nursing was 8 years. Results of factor analysis produced eigenvalues of 5.260-1.558 and a cumulative proportion of 58.032%. After two items were deleted, six stress-related factors were identified; their alpha coefficients were 0.753 to 0.912, ensuring high reliability. CONCLUSIONS: The questionnaire developed had high internal validity and high reliability, and it can thus serve as a first stage in elucidating stress among nurses engaged in palliative care on general wards.

Serum interleukin-6 levels correlate with resistance to treatment of chronic hepatitis C infection with pegylated-interferon-α2b plus ribavirin.

BACKGROUND: Interleukin (IL)-6, a pleiotropic cytokine, is increased in various types of chronic liver disease, including chronic hepatitis C (CHC). It was reported recently that IL-6 is associated with insulin resistance, iron metabolism and interferon resistance, which may affect the outcome of antiviral treatment. In this study, we investigated the association of serum IL-6 levels with outcomes of pegylated interferon (PEG-IFN) plus ribavirin (RBV) combination therapy. METHODS: We included 149 CHC patients and measured serum IL-6 levels at baseline and at 4, 8 and 12 weeks, and the end of treatment in 49 patients. We performed univariate and multivariate regression analyses for the association of IL-6 levels and clinical and laboratory parameters and treatment responses. RESULTS: Serum IL-6 levels were significantly higher in CHC patients than healthy subjects. Pretreatment IL-6 levels of male patients were inversely correlated with sustained virological response (SVR) in univariate analysis (P=0.012). In male patients with SVR, serum IL-6 levels decreased significantly at 4 weeks of treatment (P=0.029) and remained significantly lower than those of non-SVR patients after 4, 8 and 12 weeks of PEG-IFN plus RBV therapy. CONCLUSIONS: Our results suggest that baseline levels of IL-6, as well as their decrease during treatment, are correlated to outcomes of PEG-IFN plus RBV therapy in male patients. Further analyses of IL-6 may provide new strategies for difficult-to-treat CHC patients and prevention of hepatocarcinogenesis.

Analysis of interferon signaling by infectious hepatitis C virus clones with substitutions of core amino acids 70 and 91.

Substitution of amino acids 70 and 91 in the hepatitis C virus (HCV) core region is a significant predictor of poor responses to peginterferon-plus-ribavirin therapy, while their molecular mechanisms remain unclear. Here we investigated these differences in the response to alpha interferon (IFN) by using HCV cell culture with R70Q, R70H, and L91M substitutions. IFN treatment of cells transfected or infected with the wild type or the mutant HCV clones showed that the R70Q, R70H, and L91M core mutants were significantly more resistant than the wild type. Among HCV-transfected cells, intracellular HCV RNA levels were significantly higher for the core mutants than for the wild type, while HCV RNA in culture supernatant was significantly lower for these mutants than for the wild type. IFN-induced phosphorylation of STAT1 and STAT2 and expression of the interferon-inducible genes were significantly lower for the core mutants than for the wild type, suggesting cellular unresponsiveness to IFN. The expression level of an interferon signal attenuator, SOCS3, was significantly higher for the R70Q, R70H, and L91M mutants than for the wild type. Interleukin 6 (IL-6), which upregulates SOCS3, was significantly higher for the R70Q, R70H, and L91M mutants than for the wild type, suggesting interferon resistance, possibly through IL-6-induced, SOCS3-mediated suppression of interferon signaling. Expression levels of endoplasmic reticulum (ER) stress proteins were significantly higher in cells transfected with a core mutant than in those transfected with the wild type. In conclusion, HCV R70 and L91 core mutants were resistant to interferon in vitro, and the resistance may be induced by IL-6-induced upregulation of SOCS3. Those mechanisms may explain clinical interferon resistance of HCV core mutants.

Inhibitory effect of a triterpenoid compound, with or without alpha interferon, on hepatitis C virus infection.

A lack of patient response to alpha interferon (α-IFN) plus ribavirin (RBV) treatment is a major problem in eliminating hepatitis C virus (HCV). We screened chemical libraries for compounds that enhanced cellular responses to α-IFN and identified a triterpenoid, toosendanin (TSN). Here, we studied the effects and mechanisms of action of TSN on HCV replication and its effect on α-IFN signaling. We treated HCV genotype 1b replicon-expressing cells and HCV-J6/JFH-infected cells with TSN, with or without α-IFN, and the level of HCV replication was quantified. To study the effects of TSN on α-IFN signaling, we detected components of the interferon-stimulated gene factor 3 (ISGF3), phosphorylated signal transducer and activator of transcription 1 (STAT1), and STAT2 by Western blotting analysis; expression levels of mRNA of interferon regulatory factor 9 using real-time reverse transcription-PCR (RT-PCR); and interferon-stimulated response element reporter activity and measured the expression levels of interferon-inducible genes for 2',5'-oligoadenylate synthetase, MxA, protein kinase R, and p56 using real-time RT-PCR. TSN alone specifically inhibited expression of the HCV replicon (50% effective concentration = 20.6 nM, 50% cytotoxic concentration > 3 µM, selectivity index > 146). Pretreatment with TSN prior to α-IFN treatment was more effective in suppressing HCV replication than treatment with either drug alone. Although TSN alone did not activate the α-IFN pathway, it significantly enhanced the α-IFN-induced increase of phosphorylated STATs, interferon-stimulated response element activation, and interferon-stimulated gene expression. TSN significantly increased baseline expression of interferon regulatory factor 9, a component of interferon-stimulated gene factor 3. Antiviral effects of treatment with α-IFN can be enhanced by pretreatment with TSN. Its mechanisms of action could potentially be important to identify novel molecular targets to treat HCV infection.

IL-6-mediated intersubgenotypic variation of interferon sensitivity in hepatitis C virus genotype 2a/2b chimeric clones.

Mechanisms of difference in interferon sensitivity between hepatitis C virus (HCV) strains have yet to be clarified. Here, we constructed an infectious genotype2b clone and analyzed differences in interferon-alpha sensitivity between HCV-2b and 2a-JFH1 clones using intergenotypic homologous recombination. The HCV-2b/JFH1 chimeric virus able to infect Huh7.5.1 cells and was significantly more sensitive to IFN than JFH1. IFN-induced expression of MxA and 25-OAS was significantly lower in JFH1 than in 2b/JFH1-infected cells. In JFH1-infected cells, expression of SOCS3 and its inducer, IL-6, was significantly higher than in 2b/JFH1-infected cells. The IFN-resistance of JFH1 cells was negated by siRNA-knock down of SOCS3 expression and by pretreatment with anti-IL6 antibody. In conclusion, intergenotypic differences of IFN sensitivity of HCV may be attributable to the sequences of HCV structural proteins and can be determined by SOCS3 and IL-6 expression levels.

Antiviral effects of the interferon-induced protein guanylate binding protein 1 and its interaction with the hepatitis C virus NS5B protein.

UNLABELLED: Interferons (IFNs) and the interferon-stimulated genes (ISGs) play a central role in antiviral responses against hepatitis C virus (HCV) infection. We have reported previously that ISGs, including guanylate binding protein 1 (GBP-1), interferon alpha inducible protein (IFI)-6-16, and IFI-27, inhibit HCV subgenomic replication. In this study we investigated the effects of these ISGs against HCV in cell culture and their direct molecular interaction with viral proteins. HCV replication and virus production were suppressed significantly by overexpression of GBP-1, IFI-6-16, or IFI-27. Knockdown of the individual ISGs enhanced HCV RNA replication markedly. A two-hybrid panel of molecular interaction of the ISGs with HCV proteins showed that GBP-1 bound HCV-NS5B directly. A protein truncation assay showed that the guanine binding domain of GBP-1 and the finger domain of NS5B were involved in the interaction. Binding of NS5B with GBP-1 inhibited its guanosine triphosphatase GTPase activity, which is essential for its antiviral effect. Taken together, interferon-induced GBP-1 showed antiviral activity against HCV replication. CONCLUSION: Binding of the HCV-NS5B protein to GBP-1 countered the antiviral effect by inhibition of its GTPase activity. These mechanisms may contribute to resistance to innate, IFN-mediated antiviral defense and to the clinical persistence of HCV infection.

Portal gas in a diabetic patient under pharmacotherapy with an alpha-glucosidase inhibitor: report of a case with emphasis on US findings.

Portal gas is relatively rare, and its relation to ischemic bowel diseases has been emphasized. We report the case of a 56-year-old diabetic man under pharmacotherapy with an alpha-glucosidase inhibitor in which portal gas was incidentally detected by ultrasound (US). It showed multiple echo spots moving in the portal vein. Doppler signals confirmed them to be bidirectional and spiky, which immediately led to the diagnosis of portal gas. A change in oral antidiabetic drug caused the portal gas to disappear. We stress the usefulness of US and Doppler US for detecting and diagnosing portal gas. Although detailed analysis of a larger series of diabetic patients under this therapy is needed to draw a definitive conclusion, our observation merits attention. We also briefly review the literature.

Adult T-cell leukemia/lymphoma presenting multiple lymphomatous polyposis.

Multiple lymphomatous polyposis (MLP) is an unusual form of non-Hodgkin's lymphoma characterized by polyps throughout the gastrointestinal tract. It has been reported that most MLP are observed in cases with mantle cell lymphoma of B-cell type. We herein present a case of a 66-year-old man with adult T-cell leukemia/lymphoma (ATLL). Colonoscopy revealed MLP throughout the colon and histopathological findings of ATLL cell infiltration. The patient died despite combination of chemotherapy. The literature of manifestations of colonic involvement of ATLL is reviewed and the importance of endoscopic evaluation to differentiate ATLL intestinal lesions from opportunistic infectious enterocolitis is discussed.

Multiple anechoic hepatic nodules in a patient with malignant lymphoma: report of a case with an emphasis on B-mode sonograms.

We present a case of hepatic malignant lymphoma (ML) in which the hepatic ML nodules were imaged as round anechoic nodules with posterior echo enhancement, mimicking hepatic cysts on B-mode ultrasonography (US). However, the boundary echo between the nodules and the surrounding hepatic tissue seemed to be less distinct than that of a hepatic cyst. Contrast-enhanced US showed the nodules to be hypervascular, which ruled out the possibility of hepatic cysts. Our observation stresses the importance of boundary echo for the diagnosis of hepatic ML on B-mode US. We also offer a possible explanation for this phenomenon.

[Recurrent esophageal cancer with complete response to TS-1 chemotherapy].

An 80-year-old man was admitted to our hospital for treatment of recurrent esophageal cancer in December, 2004. He was diagnosed as having esophageal cancer of stage IVa (T2N4M0) in October, 2002, and he received chemoradiotherapy (nedaplatin (CDGP)/5-fluorouracil (5-FU) total 6 course+60 Gy). Afterwards, lymph nodes recurred, and two courses of CDGP/vindesine were given. Then, the primary lesion showed a complete response (CR), and lymph nodes a partial response (PR). In December, 2004, paraesophageal lymph nodes were enlarged to the size of 7 cm. On admission, because of renal disturbance and dementia with advanced age, we chose chemotherapy with TS-1 (100 mg/body/day, three weeks of administration, then two weeks of withdrawal). He had adverse effects of hematotoxicity of grade 3, and non-hematotoxicity of grade 1. He received 6 courses of this regimen and eventually showed CR. Serum SCC was decreased from 4.7 ng/mL to 0.9 ng/mL. At present,the lesions have not recurred during the follow-up for 18 months.

Portal gas in a patient with acute obstructive cholangitis: report of a case with emphasis on US findings.

Portal gas is relatively rare, and its relationship to ischemic bowel diseases has been emphasized. We report the case of a 70-year-old woman with acute obstructive cholangitis in whom portal gas was detected by ultrasonography (US) but not by computed tomography (CT). The former showed multiple echo spots moving in the portal vein. Doppler signals confirmed them to be bidirectional and spiky, which immediately led to the diagnosis of portal gas. Immediate appropriate antibiotic treatment and biliary drainage yielded the disappearance of the portal gas. We stress the usefulness of US and Doppler US for detecting and diagnosing portal gas. Our observation suggests that when portal gas is detected by US, the possibility of cholangitis should be included in the differential diagnosis.

Insetos aquáticos do açude São José dos Cordeiros (semi-árido paraibano) com ênfase em Chironomidae / Aquatic insects of São José dos Cordeiros dam (Paraiban semi-arid) with emphasis in Chironomidae

Com o objetivo de estudar a composição da fauna de Chironomidae e outros insetos aquáticos do açude São José dos Cordeiros (07°23'S e 36° 49'W), semi-árido paraibano, coletas qualitativas bimestrais foram realizadas durante o período de julho/1998 a julho/1999. Utilizou-se para isso um pegador manual com 0,50 mm de abertura de malha. Os arastos foram feitos junto a vegetação da margem e as amostras fixadas em formol a 10por cento. Para a triagem do material utilizou-se bandejas iluminadas e a identificação dos organismos foi feita através de estereomicroscópio. Foram determinadas algumas variáveis físicas e químicas da água para correlacionar com os dados biológicos. Aedokritus foi o gênero de Chironomidae dominante e freqüente no sedimento do açude, contribuindo com uma abundância máxima de 94,47por cento em janeiro/99. Já Dicrotendipes sp3, apenas foi encontrado em julho/98 (12,50por cento da fauna de insetos aquáticos). Além de Chironomidae, observamos a ocorrência de Ceratopogonidae (Diptera), Gomphidae (Odonata), Coleoptera e Campsurus sp.(Polymitarcydae, Ephemeroptera) A abundância de muitos gêneros de quironomídeos é significativamente correlacionada com a matéria orgânica do sedimento. Durante o período de setembro/98 a janeiro/99 observamos um aumento na porcentagem de matéria orgânica do sedimento, o que correspondeu a um aumento na abundância de Aedokritus sp. e uma conseqüente redução da abundância de Gomphidae. Portanto, mudanças nas variáveis físicas e químicas da água, associada principalmente a um aumento na quantidade de matéria orgânica pode produzir um conseqüente decréscimo na biomassa de insetos aquáticos.