Decreased rotational flow and circumferential wall shear stress as early markers of descending aorta dilation in Marfan syndrome: a 4D flow CMR study.

BACKGROUND: Diseases of the descending aorta have emerged as a clinical issue in Marfan syndrome following improvements in proximal aorta surgical treatment and the consequent increase in life expectancy. Although a role for hemodynamic alterations in the etiology of descending aorta disease in Marfan patients has been suggested, whether flow characteristics may be useful as early markers remains to be determined. METHODS: Seventy-five Marfan patients and 48 healthy subjects were prospectively enrolled. In- and through-plane vortexes were computed by 4D flow cardiovascular magnetic resonance (CMR) in the thoracic aorta through the quantification of in-plane rotational flow and systolic flow reversal ratio, respectively. Regional pulse wave velocity and axial and circumferential wall shear stress maps were also computed. RESULTS: In-plane rotational flow and circumferential wall shear stress were reduced in Marfan patients in the distal ascending aorta and in proximal descending aorta, even in the 20 patients free of aortic dilation. Multivariate analysis showed reduced in-plane rotational flow to be independently related to descending aorta pulse wave velocity. Conversely, systolic flow reversal ratio and axial wall shear stress were altered in unselected Marfan patients but not in the subgroup without dilation. In multivariate regression analysis proximal descending aorta axial (p = 0.014) and circumferential (p = 0.034) wall shear stress were independently related to local diameter. CONCLUSIONS: Reduced rotational flow is present in the aorta of Marfan patients even in the absence of dilation, is related to aortic stiffness and drives abnormal circumferential wall shear stress. Axial and circumferential wall shear stress are independently related to proximal descending aorta dilation beyond clinical factors. In-plane rotational flow and circumferential wall shear stress may be considered as an early marker of descending aorta dilation in Marfan patients.

Human rhinovirus infections in symptomatic and asymptomatic subjects.

The role of rhinovirus asymptomatic infections in the transmission among close contacts subjects is unknown. We tested health care workers, a pair of one child and a family member and immunocompromised patients (n =191). HRV were detected on 22.9% symptomatic and 3.6% asymptomatic cases suggesting lower transmission among contacts.

Rhinovirus detection using different PCR-based strategies.

Human rhinoviruses (HRVs) are the major cause of the common cold. HRVs were recently reclassified into the Enterovirus genus (HEV) in the Picornaviridae family. HRVs and other members of the HEV genus share many common features, including sense RNA genomes and partial nucleotide sequence identity. The aim of this study was to evaluate different HRV detection strategies. Samples from adults with acute respiratory infection (n = 291) who were treated in Sao Paulo Hospital (2001-2003) were tested using three assays. The first assay detected picornaviruses by RT-PCR and hybridization, the second detected rhinoviruses using RT-PCR/sequencing, and the third differentiated HRV from HEV using duplex semi-nested-RT-PCR. Analysis of the results obtained from the first two strategies revealed 83% concordance. Discordant samples were then evaluated by the third protocol, and 82% were negative. The picornavirus detection protocol was more sensitive but less specific than the rhinovirus detection protocols. The semi-nested protocol utilized in the present study was less sensitive and was not useful in differentiating HRV from HEV. Sequencing assays examining different genes would address the best strategy of confirming rhinovirus and enterovirus infections.

Effect of a single tetanus-diphtheria vaccine dose on the immunity of elderly people in São Paulo, Brazil.

Epidemiological data regarding tetanus and diphtheria immunity in elderly people in Brazil are scarce. During the First National Immunization Campaign for the Elderly in Brazil in April 1999, 98 individuals (median age: 84 years) received one tetanus-dyphtheria (Td) vaccine dose (Butantan Institute, lot number 9808079/G). Inclusion criteria were elderly individuals without a history of severe immunosuppressive disease, acute infectious disease or use of immunomodulators. Blood samples were collected immediately before the vaccine and 30 days later. Serum was separated and stored at -20 degrees C until analysis. Tetanus and diphtheria antibodies were measured by the double-antigen ELISA test. Tetanus and diphtheria antibody concentrations lower than 0.01 IU/mL were considered to indicate the absence of protection, between 0.01 and 0.09 IU/mL were considered to indicate basic immunity, and values of 0.1 IU/mL or higher were considered to indicate full protection. Before vaccination, 18% of the individuals were susceptible to diphtheria and 94% were susceptible to tetanus. After one Td dose, 78% became fully immune to diphtheria, 13% attained basic immunity, and 9% were still susceptible to the disease. In contrast, 79% remained susceptible to tetanus, 4% had basic immunity and 17% were fully immune. Although one Td dose increases immunity to diphtheria in many elderly people who live in Brazil, a complete vaccination series appears to be necessary for the prevention of tetanus.

Prevalence of serological markers of hepatitis B virus in pregnant women from Paraná State, Brazil.

The prevalence of hepatitis B virus (HBV) in Brazil increases from South to North but moderate to elevated prevalence has been detected in the Southwest of Paraná State. The prevalence of serological markers of HBV was evaluated in 3188 pregnant women from different counties in Paraná State and relevant epidemiological features were described. The prevalence of HBV markers in pregnant women for the state as a whole was 18.5% (95% CI = 17.2-19.9), ranging from 7.2% in Curitiba to 38.5% in Francisco Beltrão. The endemicity of HBV marker prevalence in pregnant women was intermediate in Cascavel, Foz do Iguaçu, and Francisco Beltrão, and low in Curitiba, Londrina, Maringá, and Paranaguá. Multiple logistic regression showed that HBV marker prevalence increased with age, was higher among black women, among women of Italian and German descent, and among women who had family members in neighboring Rio Grande do Sul State. Univariate analysis showed that HBV marker prevalence was also higher among women with no education or only primary education, with a lower family income and whose families originated from the South Region of Brazil. Pregnant women not having positive HBV markers (anti-HBc, HBsAg or anti-HBs detected by ELISA) corresponded to 73.7% of the population studied, implying that HBV vaccination needs to be reinforced in Paraná State. The highest prevalence was found in three counties that received the largest number of families from Santa Catarina and Rio Grande do Sul, where most immigrants were of German or Italian ascendance. This finding probably indicates that immigrants that came to this area brought HBV infection to Southwestern Paraná State.

Risk factors for poor immune response to influenza vaccination in elderly people.

Influenza vaccination of elderly people is efficacious and cost effective for the prevention of influenza and its complications. Some studies have pointed out low immunogenicity in this group. Health status has been poorly investigated as a risk factor that may influence the immune response to influenza vaccine. We established an immunization response study of a highly-matched elderly population in a nursing home. One-hundred-twenty subjects of Ashkenazian origin had their vaccine-induced antibody response assessed. Good response was obtained in 30.8% (37/120), and 31.7% (38/120) did not react. A lack of good response was found to be associated with dementia (P=0.016) in a multivariate analysis. In addition to dementia, malnutrition was frequently observed among poor responders, suggesting that these factors should be considered in vaccination studies. Chemoprophylaxis in addition to vaccination for elderly presenting dementia should be considered, particularly for those people living nursing homes.

Essential thrombocythemia--clinical features, therapy and follow-up of 12 cases.

The authors analyzed twelve patients with symptomatic essential throthrombocythemia (E.T.) diagnosed from 1983 to 1991. Haemorrhagic and thrombotic phenomena were the main presenting features. Treatment consisted mostly of alpha-interferon (IFN-alpha 2b) subcutaneously in dosage ranging from 3 to 5 MU/m2 and hydroxyurea (HU) in conventional dosage. A clinical response was seen in seven patients treated with IFN-alpha 2b (4 CR and 2 PR), and in four patients treated with HU (3 CR and 1 PR). No significant side effects were observed. Our findings indicate that IFN-alpha 2b offers a non-leukaemogenic and very promising therapeutic alternative for E.T.

Beta adrenergic modulation of spontaneous microcontractions and electrical field-stimulated contractions in isolated strips of rat urinary bladder from normal animals and animals with partial bladder outflow obstruction.

Spontaneous microcontractions and electrical field stimulation (EFS)-evoked contractions in isolated rat bladder strips from normal and from 6 weeks partial bladder outflow obstruction (pBOO) animals were studied to identify the potential site of action for the ß3-adrenoceptor (AR) agonist mirabegron in detrusor overactivity in rats. For this, effects of the ß-AR agonist isoprenaline and mirabegron were tested in presence or absence of selective antagonists for ß-AR subtypes, namely CGP-20712A for ß1-AR, ICI-118,551 for ß2-AR, and L-748,337 for ß3-AR. In detrusor strips from both normal and obstructed animals, EFS-induced contractions were weakly affected by isoprenaline and even less so by mirabegron. In contrast, microcontraction activity was more potently reduced by isoprenaline (pIC50 7.3; Emax ±85 %), whereas mirabegron showed a small effect. In pBOO strips, concentration response curves for isoprenaline and mirabegron at inhibition of EFS and spontaneous microcontractions were similar to those in normal strips. Isoprenaline-induced inhibition of microcontractions and EFS was antagonized by the ß1-AR antagonist, but not by the ß2- and ß3-AR antagonists. In the context of ß3-AR-mediated bladder functions for mirabegron in other experiments, the current data question a role for effects at spontaneous microcontractions, or neurogenic detrusor stimulation in the mode of action for mirabegron in vivo, since functional bladder effects for mirabegron are reported to occur at much lower concentrations.

Prostaglandin E2 excitatory effects on rat urinary bladder: a comparison between the ß-adrenoceptor modulation of non-voiding activity in vivo and micro-contractile activity in vitro.

Prostaglandin E2 (PGE2) is well known to modulate urinary bladder functions, but it is also thought to be involved in the pathophysiology of lower urinary tract dysfunctions, since high levels of PGE2 have been found in overactive bladder (OAB) patients. ß-Adrenoceptors are major players in detrusor muscle relaxation, and the selective ß3-adrenoceptor (AR) agonist mirabegron was recently approved for the treatment of overactive bladder (OAB). ß-Adrenoceptor modulation of PGE2 excitatory effects on bladder detrusor muscle was investigated by i.v. mirabegron after intravesical PGE2 infusion in conscious rats. Non-voiding activity (NVA) was assessed under isovolumetric conditions. In addition, mirabegron and isoprenaline (0.01-10 µM) were studied on PGE2-increased micro-contractile activity during isometric tension recordings of intact isolated bladder muscle strips. Our investigations showed that PGE2 dramatically increased NVA in vivo and spontaneous micro-contractions in vitro. In vivo administration of mirabegron (0.1, 0.3 and 3 mg/kg) reduced PGE2-augmented NVA in dose-dependent manner, while the PGE2-increased micro-contractions in isolated bladder strips were poorly inhibited. Isoprenaline inhibited PGE2-augmented micro-contractions in a concentration-dependent manner and had a higher potency compared to mirabegron. The apparent pKB of 7.25 for metoprolol at the isoprenaline concentration-response curve for PGE2-augmented micro-contractions suggests a ß1-AR-mediated.

The characteristics of intrinsic complex micro-contractile activity in isolated strips of the rat bladder.

In the resting and un-stimulated state, the bladder wall is not quiescent and discrete contractile events, microcontractions, can be recorded in almost all species. This activity contributes to the active element of compliance and to the basal resting tension. This intrinsic activity underpins the more complex phasic activity, non-voiding activity (NVA) that can be seen to increase progressively as the bladder is filled. The NVA represents the motor component of a motor sensory system that relays information to the CNS on bladder volume. Despite the importance of this intrinsic motor activity, little is known about the mechanisms involved in its generation and modulation. The present experiments were done on isolated hemi-bladders from normal rats and measurements made of the intrinsic motor activity. Detailed analysis of the resting state reveals the presence of discrete phasic contractile events, micro-contractions that range in amplitude from 0.1-0.6 mN. These events seem to occur randomly and the basal activity has the appearance of 'noise'. An analysis of the frequency amplitude distribution of the contractile events, reveals that the total activity appears to be the sum of a number of discrete contractile units, each generating a phasic contraction about a specific mean value and with characteristic frequency. In a hemi-bladder, there are between 20-30 units generating the activity at rest. Using the timed integral of the activity (product of amplitude and frequency), it was noted that the activity was increased by the muscarinic agonist carbachol, but it was decreased by the ß-adrenergic agonist isoprenaline. Stretching the preparations also increased the activity. Using these observations, a simple model of the structural and functional organisation of the isolated rat bladder is proposed: the wall appears to be arranged into a number of discrete motor units acting independently. However, the activity can be stimulated or inhibited by pharmacological agents and mechanically (stretch). The possible relevance of this activity, its relationship to NVA and in relation to the mode of action of drugs are discussed. [Corrected]

Salivary testing for human immunodeficiency virus type 1 infection in children born to infected mothers in Sao Paulo, Brazil. The Sao Paulo Collaborative Study for Vertical Transmission of HIV-1.

OBJECTIVE: To validate a method for salivary testing for HIV infection in children older than 12 months. METHODS: Oral fluid samples were collected via sponge foam swabs from children born to HIV-positive mothers and were tested for antibodies to HIV-1 and HIV-2 with an IgG antibody capture enzyme-linked immunosorbent assay and a modified Western blot for confirmation. In each child serum antibody status was the standard used to validate the salivary antibody test. RESULTS: We obtained 331 oral fluid samples from children born to HIV-positive mothers. The specificity and sensitivity of salivary testing compared with results on sera were both 100% (297 of 297 (95% confidence interval 98.8 to 100%) and 34 of 34 (95% confidence interval 89.7 to 100%), respectively). Compliance in the study population increased from 91% to 97% when mothers were offered the opportunity to provide oral fluid from their children instead of blood specimens. CONCLUSION: Salivary testing provides an accurate and acceptable noninvasive method for assessing the HIV infection status of children born to infected mothers by using IgG antibody capture enzyme-linked immunosorbent assay alone with a strategy of duplicate retesting of reactive specimens.

Use of the in vitro induced antibody production test (IVIAP) to elucidate inconclusive status of HIV-1 infection.

Studies have demonstrated the diagnostic usefulness of in vitro production of virus-specific antibodies by peripheral blood mononuclear cells (PMBC) from HIV-infected subjects. We evaluated the IVIAP (in vitro induced antibody production) by lympocytes from peripheral blood of 30 adult patients. Samples included 10 patients with inconclusive status of HIV-1 infection on previous serologic screening (2 blood donors, 8 with high risk behavior), 10 AIDS patients (CDC II-IV), and 10 known seronegative subjects. Positive IVIAP results were obtained on 2 of 10 inconclusive cases, earlier than seroconversion would demonstrate. The 8 remaining cases resulted in a negative outcome on IVIAP test, even in 2 seronegative homosexuals presenting Kaposi's sarcoma. Results showed 100% concordance either with a clinical/serological follow-up done after IVIAP tests or PCR performed for Kaposi's cases. Also, no false-positive or false-negative was detected on control groups. We concluded that IVIAP could identify the real status of HIV infection in a shorter time and with low cost compared to conventional serological methods currently available. The IVIAP test is easily performed so that can be considered as a routine supplemental test.

Evaluation of a rapid test (QuickVue) compared with the shell vial assay for detection of influenza virus clearance after antiviral treatment.

QuickVue influenza rapid diagnostic test (Quidel Corp., San Diego, CA, USA) was compared with the classical shell vial assay for evaluation of influenza virus clearance in patients treated with antiviral drugs. The shell vial assay was carried out on nasopharyngeal samples obtained from volunteers for a neuraminidase-inhibitor clinical trial protocol with 24 h or less from the onset of symptoms of influenza before the use of antiviral (day 1). Follow-up included samples collected after 24 and 72 h of therapy (day 2 and 4). The rapid test was retrospectively carried out in frozen samples. Test results on 99 samples from 33 adults were compared and the shell vial assay was considered the gold standard. The overall rate of detection for the shell vial assay was 39.4% and for QuickVue was 35.5%, with a concordance of 79.8%. The sensitivity obtained for QuickVue was 74.4% and the specificity was 82.7%. Comparison of test results day by day in the follow-up resulted: day 1, higher sensitivity of QuickVue test (85.5%, 24/29); day 2, agreement on positive and negative results between QuickVue and shell vial was 60.6% (20/33); day 4, all test results in samples collected after 72 h of therapy were negative. The QuickVue test showed good sensitivity for the diagnosis of influenza-like illnesses. This rapid test kit can be an alternative tool for interventions in disease management.

HTLV infection in a group of prostitutes and their male sexual clients in Brazil: seroprevalence and risk factors.

Sera from 653 female prostitutes and 153 male sexual clients living in the city of Santos, São Paulo, Brazil, were tested for the presence of antibodies to human T cell lymphotropic virus types I and II. Seroprevalence for HTLV-I in the females was 2.8% and in the males 2.0%. Infection by HTLV-II could not be demonstrated. Seropositivity to HTLV-I was not associated with intravenous drug use, modality of sexual behaviour or a history of sexually transmitted disease. Among the prostitutes, the prevalence of anti-HTLV-I antibodies was 3 times higher in those with a history of blood transfusion (P = 0.01).

Unexpected low prevalence of delta antibodies in the east Amazon region and São Paulo: evidence for regional differences in the epidemiology of delta hepatitis virus within Brazil.

Antibodies (anti-HD) to hepatitis delta virus (HDV) were tested by radioimmunoassay in 207 human serum samples from the eastern Amazon (states of Pará and Amapá) and São Paulo, Brazil. 42 Amazon HBsAg asymptomatic carriers were negative for anti-HD. 84 São Paulo HBsAg asymptomatic carriers were also negative. Among the 81 HBsAg patients from São Paulo with different liver diseases, only one had anti-HD. Liver biopsy of this chronic active hepatitis case was positive for HBsAg, HBcAg and HDAg in liver, by an immunoperoxidase technique. The low prevalence of HDV infections in São Paulo and eastern Amazon was unexpected and contrasts with the recent reports of high prevalence in the western Amazon region. Such regional differences emphasize the need for extensive and precise worldwide epidemiological studies of HDV.

In vitro induced antibody production for the diagnosis of herpes simplex virus infection in immunosuppressed patients.

We developed and evaluated a specific test for herpes simplex virus (HSV) infection based on the secretion of HSV-specific antibodies by lymphocytes stimulated in vitro with HSV-1 antigens. The in vitro induced antibody production (IVIAP) test was used for the diagnosis of HSV infection in 43 seropositive selected subjects: 9 healthy subjects (controls), 30 symptomatic patients (26 of them immunocompromised and 4 immunocompetent) and 4 patients with varicella zoster infection. Anti-HSV antibodies were detected by an immune assay using an anti-human IgG peroxidase conjugate. The test showed a sensitivity of 93% (15/16) and specificity of 92% (1/13) which were confirmed by positive culture or clinical and laboratory follow-up. One AIDS patient had a false-negative result and one false-positive result (1/9) was obtained among the healthy subjects. All patients infected with varicella zoster virus were negative to the IVIAP test. The test is rapid, inexpensive, easy to interpret and can be used for the diagnosis of HSV infections, especially in immunocompromised patients.

Production of anti-HBsAg monoclonal antibodies.

The production of monoclonal antibodies against the HBsAg is reported. Balb/c mice immunized against a commercial vaccine were used. Upon fusion of spleen cells from an animal having a high titer with the SP2/0 myeloma cell line, we obtained 6 stable cell lines, all of the IgG1 subclass. They showed a wide range of specificities against the classical HBsAg subtypes. These monoclonal antibodies can be used as the basis for the development of new methods for the screening and study of the hepatitis B virus.

In vitro-induced antibody production in chronic hepatitis C virus infection.

The objectives of the present study were to assess the in vitro-induced anti-hepatitis C virus (HCV) antibody production (IVIAP) in relation to the clinical, biochemical, virologic and histologic variables of patients with HCV infection. The study included 57 patients (60% males) with HCV infection (anti-HCV and HCV-RNA positive). Alanine aminotransferase (ALT) was elevated in 89% of the patients. Mean viral load was 542,241 copies/ml and histology of the liver showed chronic hepatitis in 27/52 (52%) and cirrhosis in 11/52 (21%) patients. IVIAP levels were determined by immunoenzymatic assay at median absorbance of 0.781 at 450 nm. IVIAP was negative in 14% of the patients. When groups with IVIAP levels above and below the median were compared, high IVIAP levels were associated with the male sex, elevated ALT levels and more advanced disease stage. After logistic regression analysis, advanced histologic damage to the liver remained as the only independent variable associated with elevated IVIAP levels. Using a receiver operator characteristic curve, the best cut-off level for IVIAP was established (= 1.540), with 71% sensitivity and 94% specificity for the detection of more advanced disease stages (grades 3 and 4). These findings are consistent with the participation of immunological mechanisms in the genesis of the hepatic lesions induced by HCV and indicate that the IVIAP test may be useful as a noninvasive marker of liver damage either alone or in combination with other markers.

High prevalence of hepatitis C infection in a Brazilian prison: identification of risk factors for infection.

Hepatitis C virus (HCV) causes infectious hepatitis worldwide. It is transmitted mainly by blood products and sharing of intravenous paraphernalia during illicit drug use. High prevalence rates have been described among specific groups considered to be at higher risk for HCV infection, including prison inmates. The objectives of this study were: to determine the HCV seroprevalence among inmates of Casa de Detenção de São Paulo; to identify risk factors for HCV infection; and to compare the seroprevalence of HCV to other blood borne or sexually transmitted diseases. From December, 1993, to January, 1994, a total of 779 inmates were interviewed to collect information on sociodemographic status, sexual behavior, and past experience with illicit drugs. Blood samples were obtained from 756 inmates for serological tests. 310 (41%) blood samples were positive for anti-HCV, 425 (56.2%) were negative, and 21 (2.8%) showed indeterminate results. In this population, we found a seroprevalence of 13.7% for HIV, 3.3% for syphilis (VDRL), and 68.1% for hepatitis B virus previous infection. Four variables were each identified as associated with a positive anti-HCV serologic test: a positive VDRL (OR = 2.63 IC 95% 1.08 to 6.36); a time of current imprisonment longer than 130 months (OR = 2.44 IC 95% 1.04 to 5.71); previous incarceration at Casa de Detenção de São Paulo (OR = 1.73 IC 95% 1.19 to 2.52) and; illicit drug use before admission to the Casa de Detenção de São Paulo (OR = 1.64 IC 95% 1.15 to 2.33). The seroprevalence of HCV antibodies among the study population was high (41%), indeed, one of the highest clusters of HCV infection recorded until now. Four variables were each shown to be associated with HCV infection. The simultaneous presence of these 4 variables is associated with an 82% probability of being anti-HCV positive. Although risk factor analysis indicates most HCV infections occur prior to inprisonment, initiation of control measures to prevent continued transmission after incarceration should be done.

Relationship between the prevalence of antibodies to hepatitis B core antigen and arbovirus in fishermen from the Ribeira Valley, Brazil.

Sera from 299 fishermen 16 to 80 years old, residents in Cananeia and Iguape counties, southern cost of São Paulo State, Brazil, were studied in order to identify a possible association between the prevalence of specific antibodies to the hepatitis B virus (HBV) and exposure to haematophagus mosquitoes evaluated by the prevalence of arbovirus antibodies. This professional group presented the highest prevalence of arbovirus antibodies (54.1%) in past investigations carried out in this heavily forested region. Detection of antibody to hepatitis B core antigen (anti-HBc) in the sera was done by enzyme immunoassay (Roche). Prevalence of anti-HBc antibodies in this group was 31.4% (94/299) which is very high compared with 7.2% to 15.0% for different groups of healthy adults in State of São Paulo. No significant difference is observed between the prevalences of HBV antibodies in Iguape and Cananeia. Prevalence of anti-HBc and anti-arbovirus antibodies increases with age. There is a concordance in the distribution according to age groups of the frequency of anti-HBc and anti-arbovirus positive sera. Ag HBs was detected in 4% of the studied sera. These results support the hypothesis that the transmission of the hepatitis B virus and the arboviruses may be due to the same factor, one of the possibilities would be by anthropophilic mosquitoes.