Endothelin receptor selectivity: evidence from in vitro and pre-clinical models of scleroderma

Scleroderma [systemic sclerosis (SSc)] is a spectrum of connective tissue diseases characterized by micro- and macro-vasculopathy, inflammation and autoimmunity and tissue remodelling that often leads to excessive scarring and fibrosis in both interstitial and vascular compartments. Pre-clinical investigations and gene association studies have led to improved understanding of the cell and molecular mechanisms underlying disease pathogenesis and to the identification of key molecular candidates that may represent potentially useful disease biomarkers and effective therapeutic targets. Studies on the endothelin (ET) system, pre-dominantly ET-1 and the cell surface receptors [type A (ET(A))] and type B (ET(B))], have provided evidence for an important role of this system in the vascular and fibrotic pathologies in SSc. To date, promising clinical results, utilizing dual/mixed ET receptor antagonism have been obtained in two of the vascular complications associated with SSc, ischaemic digital ulceration and pulmonary arterial hypertension. Evidence suggests that ET-1 is able to activate and re-program the functional phenotypes of vascular smooth muscle cells, microvascular pericytes and tissue fibroblasts into pro-fibrogenic cell populations with myofibroblasts-like properties. The impact of receptor-selective, over mixed-receptor, antagonism has also been studied in vitro with respect to cell differentiation and proliferation, extracellular matrix synthesis, production and deposition and in pathological cellular contraction. However, the complexity of the ET system, potential for receptor cross-talk, interactions with down-stream signal transduction cascades, as well as the potent inter-relationships with other important ligand-receptor pathways have made in vivo studies difficult to unravel. Moreover, little information is available on the role of the ET system and receptor selectivity in the recruitment and activation of mesenchymal progenitor cells in tissue remodelling and fibrosis or on the early inflammatory response. Here, we discuss the available pre-clinical evidence for the role of the ET system in tissue repair, scarring and fibrosis, using the connective tissue diseases SSc and model systems of fibrogenesis.

Expression of the Gxf1 transporter from Candida intermedia improves fermentation performance in recombinant xylose-utilizing Saccharomyces cerevisiae

The glucose/xylose facilitator Gxf1 from Candida intermedia was expressed in the recombinant xylose-fermenting Saccharomyces cerevisiae strain TMB 3057. The new strain, TMB 3411, displayed approximately two times lower K (m) for xylose transport compared to a control strain not expressing Gxf1. In aerobic batch cultivation, the specific growth rate was significantly higher at low xylose concentration, 4 g/L, when Gxf1 was expressed, whereas it remained unchanged at high xylose concentration, 40 g/L. Similarly, in aerobic-xylose-limited chemostat culture, the Gxf1-expressing strain consumed more xylose than the control strain at low dilution rates (low xylose concentration), whereas the situation was reversed at higher dilution rates (high xylose concentration). Also, under anaerobic conditions, the Gxf1-expressing strain showed faster xylose uptake and ethanol formation at low substrate concentrations. The results are discussed in relation to previous observations, which suggested that transport controlled xylose utilization in recombinant xylose-utilizing S. cerevisiae only at low xylose concentrations.

Capitalizing on the immunogenicity of dying tumor cells

Cancer cell death occurs continually during tumor development and progression, whereas the selective killing of surviving cancer cells remains the primary objective of antineoplastic treatments. Recent insights into the immunologic consequences of cancer cell death have begun to elucidate the ways in which host antitumor immunity is shaped during cancer pathogenesis and then modulated by therapeutic intervention. Dying tumor cells evoke a range of host responses, dependent in part upon the mode of cell death, which may either impede or foster additional immune-mediated cancer destruction. Within the tumor microenvironment, the capture of apoptotic tumor cells by macrophages and dendritic cells may trigger tolerance networks that contribute to immune suppression, whereas the uptake of necrotic cancer cells may engender inflammatory pathways that fuel antitumor cytotoxicity. Milk fat globule epidermal growth factor 8, a phosphatidylserine-binding protein, and MHC class I chain-related protein A, an NKG2D ligand, play key roles in these competing outcomes. A deeper understanding of the mechanisms underlying the immunogenicity of dying cells informs the crafting of strategies that exploit endogenous or treatment-induced cancer cell death as the basis for stimulating sustained host antitumor cytotoxic reactions.

A novel dry active electrode for EEG recording

The design and testing of a "dry" active electrode for electroencephalographic recording is described. A comparative study between the EEG signals recorded in human volunteers simultaneously with the classical Ag-AgCl and "dry" active electrodes was carried out and the reported preliminary results are consistent with a better performance of these devices over the conventional Ag-AgCl electrodes.

A polymorphism in the promoter region of the CD86 (B7.2) gene is associated with systemic sclerosis

Systemic sclerosis (SSc) is a connective tissue disease of unknown aetiology characterized by fibrosis of the skin and internal organs, vascular abnormalities and humoral autoimmunity. Strong T-cell-dependent autoantibody and HLA associations are found in SSc subsets. The co-stimulatory molecule, CD86, expressed by antigen-presenting cells, plays a crucial role in priming naïve lymphocytes. We hypothesized that SSc, or one of the disease subsets, could be associated with single-nucleotide polymorphisms of the CD86 gene. Using sequence specific primer-polymerase chain reaction (SSP-PCR) methodology, we assessed four CD86 polymorphisms in 221 patients with SSc and 227 healthy control subjects from the UK. Haplotypes were constructed by inference and confirmed using PHASE algorithm. We found a strong association between SSc and a specific haplotype (haplotype 5), which was more prevalent in patients than in controls (29% vs 15%, OR = 2.3, chi(2) = 12, P = 0.0005). This association could be attributed to the novel -3479 promoter polymorphism; a significant difference was observed in the distribution of the CD86 -3479 G allele in patients with SSc compared to controls (43.7% vs. 32.4%, OR = 1.7, chi(2) = 12.1, P = 0.0005). TRANSFAC analyses suggest that the CD86-3479T allele contains putative GATA and TBP sites, whereas G allele does not. We assessed the relative DNA protein-binding activity of the -3479 polymorphism in vitro using electromobility gel shift assays (EMSA), which showed that the -3479G allele has less binding affinity compared to the T allele for nuclear proteins. These findings highlight the importance of co-stimulatory pathways in SSc pathogenesis.

Environmental tobacco smoke exposure in public places of European cities

BACKGROUND

Exposure to environmental tobacco smoke (ETS) has important public health implications. The results of the first European multi-centre study that measured ETS exposure in a range of public places (transport, educational settings, and leisure facilities such as bars and restaurants) are presented.

METHOD

Nicotine vapour phase was measured using ETS passive samplers containing a filter treated with sodium bisulfate.

RESULTS

Bars and discos are the places with the highest concentrations of nicotine from ETS, median ranging from 19 to 122 microg/m(3). Restaurants had the next highest values. Concentrations of nicotine generally range from 0.1-5 microg/m(3) in airports, and from 0.5-10 microg/m(3) in train stations. Nicotine was also found in schools and universities, yet schools tended to have the lowest concentrations compared to all the other public places sampled. In hospitals levels were generally below 5 microg/m(3).

CONCLUSIONS

Although there is some variability between cities, this study shows that tobacco smoke is present in most of the studied public places. The study also showed that in areas where smoking is prohibited, concentrations of nicotine are lower than in areas where smoking is allowed but they are not zero. The results of this study indicate that policies should be implemented that would effectively reduce levels of tobacco smoke in public areas.

Single-nucleotide polymorphisms in the SPARC gene are not associated with susceptibility to scleroderma

OBJECTIVE

SPARC (secreted protein, acidic and rich in cysteine) is a matricellular protein that modulates cell-cell and cell-extracellular matrix interactions. SPARC expression is restricted mainly to sites of tissue remodelling and wound repair, and is prominent in fibrotic disorders. Single-nucleotide polymorphisms (SNPs) in the SPARC gene are reportedly linked to scleroderma in four ethnic groups: Choctaw Indians, Caucasians, African Americans and Mexican Americans. We set out to reproduce and to positionally clone these disease associations in a set of UK Caucasian scleroderma patients and ethnically matched controls.

METHODS

One hundred and twenty-one scleroderma subjects and 200 controls were genotyped by polymerase chain reaction with sequence-specific primers differing only in the 3' nucleotide corresponding to each allele of the biallelic SNPs. Scleroderma patients were analysed against controls and on the basis of their fibrosing alveolitis status as judged by high-resolution computed tomography evaluation and the extent of cutaneous involvement.

RESULTS

Eight biallelic SNPs were genotyped: three from the last untranslated exon, which had been described previously, and an additional five novel SNPs: two in the promoter region, one in exon three and two in the 3' untranslated region. Six major haplotypes were constructed across all eight SNP positions. No significant differences in genotype, allele or haplotype frequency were observed between scleroderma and controls or within scleroderma subgroups.

CONCLUSIONS

SNPs in the SPARC gene are not associated with susceptibility to scleroderma. This research adds to the genetic knowledge of the SPARC gene by identifying five novel SNPs spanning the whole gene and inserting these within the context of clearly defined haplotypes.

Albumin adsorption on alkanethiols self-assembled monolayers on gold electrodes studied by chronopotentiometry

Chronopotentiometry was used to study the adsorption of human serum albumin (HSA) to self-assembled monolayers with the following terminal functional groups: CH(3), COOH and OH. Surfaces were characterized by X-ray photoelectron spectroscopy, water contact angle measurements and cyclic voltammetry. HSA coverage of the different SAMs was investigated by chronopotentiometry and the total amount of adsorbed protein was determined using radiolabelled albumin. Both techniques have demonstrated that HSA adsorption to the different SAM-modified electrodes increases in the following order: OH<COOH<CH(3)-terminated SAMs. A good correlation between coverage and total amount of HSA adsorbed was observed for long adsorption times (900s).

Heart failure treatment in Portuguese hospitals: results of a survey

The management of heart failure in Europe is largely conducted by primary care physicians in out-patient clinics and by cardiologists and internists in hospitals. Several reports suggest differences among these specialists regarding knowledge and actual practice, and indicate that the application of guidelines is far from optimal. In order to look for differences between cardiologists and internists in terms of implementation of guidelines a survey was carried out among the directors of 83 hospital departments of cardiology and internal medicine in Portugal. The survey included questions about diagnostic and treatment protocols, special areas for management, and suggestions to improve the quality of heart failure patient treatment. The answers suggest that in Portuguese hospitals at least half of the patients with HF are treated by internists. Treatment protocols exist in about 25% of the cardiology departments but are virtually non-existent in internal medicine. The use and availability of echocardiography are high in cardiology but no more than reasonable in internal medicine. There are neither special in-hospital areas nor specialized nurses for the treatment of HF. Cardiologists recognize the need for greater specialization in this field--doctors, nurses and clinics--but this is not a priority for internists. An effort should be made to improve in-hospital HF treatment.

[Relationship between respiratory syncytial virus subtype and clinical severity in bronchiolitis]

BACKGROUND

Respiratory syncytial virus (RSV) is the most frequently implicated agent in bronchiolitis. The virus presents two antigenic subtypes (A and B). The results of studies on the relationship between viral subtype and clinical severity are conflicting.

PURPOSE

To evaluate whether the subtype of this virus constitutes an independent variable in the severity of clinical expression of RSV infection.

PATIENTS AND METHODS

We prospectively studied previously healthy children aged less than 2 years admitted for RSV infection during an epidemic season. Clinical presentation and evolution, laboratory and radiological aspects were compared in subsets of children infected with RSV subtype A or B. Clinical severity parameters included score and duration of respiratory distress, oxygen requirements, admission to the intensive care unit, mechanical ventilation and length of hospital stay.

RESULTS

Eighty-five patients were enrolled in the study (50 boys and 35 girls; mean age 4.8,4.3 months). Fifty-nine children were infected with RSV subtype A. No differences were found in age, sex or antecedents but children with subtype B were less likely to have been breast-fed. Clinical presentation and laboratory and radiological findings were similar in both groups. No statistically significant differences in clinical severity parameters were found between subsets A and B. Age less than 3 months was associated with greater duration of respiratory distress and longer hospital stay.

CONCLUSION

The results do not support the hypothesis that subtype A infection is associated with more severe respiratory syncytial virus disease.

Autocrine overexpression of CTGF maintains fibrosis: RDA analysis of fibrosis genes in systemic sclerosis

We have used representational difference analysis (RDA) to identify up-regulated genes in skin fibroblasts from fibrotic lesions obtained from patients with systemic sclerosis (scleroderma). RDA of cDNA libraries derived from fibroblasts from involved and uninvolved skin detected several differentially expressed genes. One such gene consistently up-regulated in scleroderma cells coded for human connective tissue growth factor (CTGF). Other studies described here show that the CTGF protein is readily detected in cultures of systemic sclerosis fibroblasts but was not detected in comparable normal cells. High levels of CTGF are also evident in biological fluids from patients with systemic sclerosis. TGFbeta stimulates CTGF production in both normal and systemic sclerosis fibroblasts with the latter found to be higher producers. Moreover, an analysis of constitutive and TGFbeta-induced CTGF gene activation showed altered and elevated transcriptional responses in systemic sclerosis cells compared with controls. CTGF stimulated a two- to threefold increase in proalpha1(I) collagen and fibronectin synthesis by both dermal and lung fibroblasts in culture and promoted significant matrix remodeling of fibroblast-populated three-dimensional collagen lattices. A direct relation between the overexpression of CTGF and elevated collagen synthesis was suggested by the observation that transfection of a CMV-CTGF cDNA construct and protein expression in fibroblasts increased the transcription of a Col 1alpha2 promoter-reporter construct to levels seen in systemic sclerosis fibroblasts. Using Col 1alpha2 promoter deletion constructs the CTGF responsive element was localized to the first 379 bp upstream of the transcriptional start site. These data indicate that there is an overexpression of CTGF in the systemic sclerosis cells, probably due to increased gene transcription, and suggest that the dysregulation of CTGF production is an important factor in fibroblast activation and the excessive deposition of collagen in systemic sclerosis.

[Diastolic dysfunction and left ventricular hypertrophy in familial amyloidotic polyneuropathy: a cause-effect relationship?]

TTR Met30 Familial Amyloidotic Polyneuropathy of the Portuguese type (FAP) is an incapacitating and lethal hereditary disorder that affects predominantly young adults of both genders. Portuguese type FAP patients have sensory, motor and autonomic polyneuropathy. The generalised systemic amyloid infiltration involves the heart, leading to the characteristic granular bright sparkling echocardiographic pattern. LV wall thickening occurs in the late phases of the disease. LV diastolic dysfunction has been reported in the absence of systolic dysfunction; an abnormal diastolic transmitral flow pattern assessed by pulsed wave Doppler (PW) was described. PW is very much dependent on load conditions. Tissue Doppler imaging (TDI) has been used as a more reliable method to assess long axis diastolic function.

OBJECTIVE

1--To identify the incremental value of TDI in the assessment of diastolic function in FAP. 2--To correlate diastolic pattern abnormalities and left ventricular mass index (LVMI) in FAP patients.

METHODS

We performed a prospective evaluation of 24 consecutive FAP patients and selected 14 (sinus rhythm, age < 45 years). Diastolic function was assessed by PW and classified as normal (GI-E/A > 1) or abnormal (GII-E/A < 1). TDI was performed in 4 sites of the mitral annulus (septum, lateral, inferior, anterior). Velocities of the rapid filling wave (E') and atrial contraction wave (A') were measured and E'/A' calculated. In each site we considered the TDI as normal (E'/A' > 1) or abnormal (E'/A' < 1). The LVMI was calculated by Devereux's formula.

RESULTS

Age, gender and heart rate were similar in both groups. TDI at the septal mitral annulus was normal in all of the GI patients (E'/A': 1.29 +/- 0.19) and suggestive of abnormal LV relaxation in all of the GII patients (E'/A': 0.82 +/- 0.11, p < 0.0001). TDI revealed abnormal diastolic pattern when a restricted number of sites of the mitral annulus were assessed, even in GI patients and before PW abnormalities occurred. Fractional shortening (FS) and LVMI were similar in GI and GII (FS-GI: 45.5 +/- 5.3, GII 43.5 +/- 8.1%, p: NS; LVMI--GI: 66 +/- 9.3, GII: 67 +/- 3.0 g/m2 p: NS).

CONCLUSION

The assessment of mitral annulus motion has introduced new data in the study of diastolic function of FAP patients. An abnormal LV relaxation pattern occurred early in the evolution of the disease in patients with normal LVMI and systolic function.

Tissue Doppler imaging in different locations of the mitral annulus: all different or all the same?

BACKGROUND

The assessment of the mitral annulus motion with tissue Doppler imaging is claimed to be an accurate method to quantify global left ventricular systolic and diastolic function. However, it is not yet perfectly defined which site of the annulus must be selected. Familial amyloidotic polyneuropathy of the Portuguese type (FAP) is an hereditary systemic disease in which diastolic dysfunction may occur.

AIM

1--To determine if in FAP patients the mitral annulus motion is independent of the selected site. 2--To compare pulsed wave Doppler parameters with tissue Doppler parameters in the different annular sites.

METHODS

Of 24 FAP patients studied, 14 were included. In each patient we performed conventional transmitral pulsed wave Doppler and tissue Doppler in the 4 sites of the mitral annulus and measured the velocities of the rapid filling wave e, of the atrial contraction wave a and calculated e/a ratio.

RESULTS

According to the transmitral inflow profile, patients were divided in 2 groups: Group I--normal global diastolic function and Group II--abnormal relaxation. Group I--33% of these patients showed e/a > 1 in the four sites and 67% showed e/a > 1 in at least 1, but not in all the sites. The rate of normal sites per patient was 3.1. Group II--25% of these patients showed e/a < 1 in the 4 sites of the annulus and 75% had e/a < 1 in at least 1, but not in all the sites analysed. The rate of abnormal sites/patient was 3.1. in this group. When conventional and tissue Doppler data were compared (bland and altman) the septal portion of the annulus was the one with the best correlation.

CONCLUSIONS

1--The assessment of the mitral annulus motion with tissue Doppler imaging is dependent on the site selected for study. 2--The septal site was the one that showed the highest correlation and concordance between pulsed wave Doppler and tissue Doppler. 3--The relative number of normal versus abnormal sites was determinant of the transmitral pattern. 4--Tissue Doppler imaging identified: a) among patients until now classified as normal diastolic function, a subgroup of patients with abnormal function in some sites of the annulus and b) among patients with abnormal relaxation, a subgroup with normal diastolic function in some sites of the annulus.

[Prevalence of heart failure in Portugal]

The incidence and prevalence of heart failure are increasing, which presents an enormous problem for health care systems. In Portugal, there are no studies assessing this issue. The EPICA study was designed to estimate the prevalence of chronic heart failure in Portugal in 1998. This is a community-based epidemiological survey involving 13,000 primary care recipients, selected through a two-stage sampling procedure: each GP, from a random sample of 500, with proportionality to district population, will include 26 primary care recipients recruited sequentially within each age group. The cases will be identified according to ESC Guidelines: symptoms and signs of heart failure and echocardiographic evidence of cardiac dysfunction. The individuals will be screened for echo examination on the basis of a structured questionnaire (EPICA questionnaire) that was drafted from seven questionnaires previously used in epidemiological surveys for heart failure. Age and gender adjusted estimates of the prevalence of chronic heart failure will be obtained as well as a prevalence estimate for the whole population. The study will also estimate the test statistics (sensitivity, specificity and predictive values) for the EPICA questionnaire compared to echo data, as well as the seven other questionnaires used for the diagnosis of chronic heart failure. Their agreement will also be evaluated.

PRELIMINARY RESULTS

93% of the GPs recruited have participated. The final data will be available in early 2000.

The natural history of asymptomatic moderate internal carotid artery stenosis by duplex ultrasound

The purpose of this study was to determine the rate of progression of the degree of carotid stenosis and to determine the risk of continued observation in a group of asymptomatic patients with moderate stenosis of at least one internal carotid artery. Between 1989 and 1994, 2130 patients were found to have 60-79% stenosis of at least one internal carotid artery following a duplex ultrasound examination in the authors' vascular laboratory. Of these, 465 patients (255 men, 210 women) were asymptomatic and had more than one ultrasound examination, and they form the basis of this retrospective review. The mean +/- SD age was 68.8 +/- 9.0 years. The mean +/- SD number of ultrasound examinations was 3.1 +/- 1.4 (range 2-11). The mean +/- SD follow-up was 24.4 +/- 17.6 months (range 2-79 months). Over the period of follow-up 72 patients (15.5%) progressed to 80-99% stenosis (n = 71) or to occlusion (n = 1). The estimated percentage of patients who progressed by life table methods were 5 +/- 1% at 1 year, 11 +/- 2% at 2 years and 20 +/- 3% at 3 years. There was no statistically significant difference in the rate of progression in men compared with women. Twenty-one patients had a late ipsilateral TIA or stroke. Five out of 72 patients (6.9%) who progressed had a late ipsilateral TIA compared with nine out of 393 patients (2.3%) who did not progress (estimated risk ratio 16.1, P = 0.0001). Four out of 72 patients (5.6%) who progressed had a late ipsilateral stroke compared with three out of 393 patients (0.76%) who did not progress (estimated risk ratio 23.6, p = 0.0002). The cumulative ipsilateral stroke rate using life table methods was 0.22% at 1 year, 1% at 2 years and 2.4% at 3 years. In a large cohort of asymptomatic patients, the frequency of progression of 60-79% internal carotid artery stenosis was 5% at 1 year, 11% at 2 years and 20% at 3 years. Patients who progressed were more likely to have symptoms, but the rate of unheralded stroke was relatively low over a 3-year time period. Surveillance carotid ultrasound examinations should be performed in patients with moderate carotid stenosis. Because of the lack of clear benefit, carotid endarterectomy for asymptomatic 60-79% internal carotid artery stenosis cannot be justified.

[Pulmonary embolism: a clinical case documented, in acute setting, using pulmonary scintigraphic perfusion]

The acute clinical evolution is presented of a patient with previous myocardial infarction who was admitted for dyspnea and chest pain. Acknowledging the possibility of a new ischemic event, confronted with aortic dissection or pulmonary embolism, the clinical investigation is described up to the scintigraphic diagnosis of pulmonary embolism. The clinical presentation, diagnostic investigation and therapeutic decisions are discussed, with emphasis on the usefulness of pulmonary scintigraphy.

[Acute myocardial infarct--the hospital phase and follow-up: sex-related differences]

OBJECTIVES

The aim of this study was to evaluate the differences between male and female patients, during hospitalization and follow-up, after acute myocardial infarction.

PATIENTS

The clinical data and follow-up files of 504 previously hospitalized patients were studied. The patients were divided in two groups: Group A (male, n = 434) with a mean age of 56.4 +/- 11.7 years, and Group B (female, n = 70) with a mean age of 64.1 +/- 9.2 years.

METHODS

The following parameters were studied: vascular risk factors; clinical, functional and anatomic aspects during hospitalization; therapeutic orientation and events; and mortality during follow-up.

RESULTS

Hypertension, diabetes, obesity, anterior infarction and lower ejection fraction were more common in Group B. Coronary angiography and thrombolytic therapy were performed more frequently in Group A; severe coronary disease was more common in this group (60.8% vs 38.9%, p < 0.05). During the follow-up we observed a worse prognosis in the Group B, with a higher incidence of events, morbidity and mortality. Therapeutic approach was more aggressive in the male group.

CONCLUSION

We observed a worse prognosis in the female patients after myocardial infarction, this fact may be attributed to a later age and higher previous morbidity; the therapeutic and diagnostic procedures are generally less aggressive in females, who are consequently referred for revascularization with more advanced stages of disease, and therefore with higher morbidity and mortality, in the short and long term, even though multivessel coronary disease is more common in males. Thrombolytic therapy was administered and coronary angiography was performed more often in Group A, who had more severe coronary disease.

[Individualized monitoring of the therapy with gentamycin using pharmacokinetic methods. Which method to choose?]

Gentamicin has an excellent cost/efficacy ratio for gram negative infections treatment. Its use is often limited in clinical practice by its narrow safety margins and a high incidence of toxicity. Gentamicin related nephrotoxicity is a major adverse effect, mostly in patients with other concomitant potential risk factors. As many other Authors we have found in our Internal Medicine Service during 1992 a gentamicin related nephrotoxicity incidence of 22.5%. Various empiric methods and nomograms have shown a significant incidence of error in predicting individualized gentamicin dosage regimens. Pharmacokinetics methods have demonstrated much better results regarding efficacy and toxicity. The aim of this prospective study carried out during 1993-1994 was to individualize by pharmacokinetics methods dosage regimens of gentamicin in patients with one or more concomitant risk factors of nephrotoxicity. The purpose of pharmacokinetics dosage regimens has been to achieve trough serum concentrations of gentamicin in therapeutics range-0.5 to 2 micrograms/ml-on the first 24 to 48 hours of treatment, and the maintenance in this range during all the treatment, avoiding both toxic and under therapeutic levels. The incidence of gentamicin related nephrotoxicity has been evaluated in this population. Twenty patients were studied: 18 males and 2 females aged 59.6 years (19 to 85). All had one or more potential risk factors for nephrotoxicity-65 years or more: 13, previous renal failure: 6, other nephrotoxic drugs: 10, diuretics: 4, dehydration: 5, congestive heart failure: 5, diabetes: 3, hypertension: 3. For the first 10 patients gentamicin dosage regimens have been determined by Sawchuk-Zaske pharmacokinetics method and for the subsequent 10 patients by Bayesian method. The two subpopulations had no significant differences regarding mean age, sex and potential risk factors for nephrotoxicity. Results of Sawchuk-Zaske method: 53 trough gentamicin serum concentration were obtained; 86.8% were within the therapeutic range, 7.5% were toxic and 5.7% were under therapeutic. Results of Bayesian method: 44 determinations of gentamicin through concentrations were obtained; 86.3% within therapeutic range, 2.4% were toxic and 11.3% were under therapeutic. A great variability in pharmacokinetic patient's profile has been found and explains the great variability of individualized dosage regimens of gentamicin (30 to 320 mg/day). No patients had gentamicin related nephrotoxicity. Both pharmacokinetics methods lead to a efficient and save employment of gentamicin in patients with previous renal failure and other potential risk factors for nephrotoxicity.

Heat-related deaths in Philadelphia--1993

A study of heat-related deaths associated with the 1993 heat wave in Philadelphia, Pennsylvania, was conducted. Most of these deaths were in the susceptible elderly with preexisting natural diseases who lived alone without air conditioning in upstairs bedrooms with windows shut, thus creating an even hotter environment. These excessive deaths under such conditions did not meet the standard clinical criteria for hyperthermia because of varying postmortem intervals. Therefore, the authors stress the utility of a postmortem definition of heat-related death to better define the magnitude of health risk posed by hot weather and warn public health and other agencies to take preventative measures.

Effects of a chlorhexidine varnish on the gingival status of adolescents

The purpose of this blind study was to determine the effect of a two-stage chlorhexidine varnish, after three months, on the gingival status of 11- to 15-year-old children attending a school in Rio de Janeiro, Brazil. Subjects participating in the study were randomly allocated to control (C) and treatment (T) groups, n = 53 and n = 57, respectively. All subjects were matched at baseline on age, salivary levels of mutans streptococci, and caries scores. After elimination of carious lesions, a prophylaxis was given to both groups. The chlorhexidine varnish was then painted on the entire dentition of Group T subjects only. Prior to caries elimination, and again after three months, the gingival index was used to assess the gingival status of study subjects. An average of 106.6 +/- 8.9 and 107.7 +/- 6.2 gingival sites per subject (four sites per tooth) in Groups C and T, respectively, were examined by the same calibrated examiner on two occasions. For statistical purposes, data were dichotomized [(0,1) (2,3)] for the gingival index. Independent t-tests and paired t-tests were used to analyze the data. The percentage of sites per subject with scores of two or three at the baseline were balanced between study groups (3.7 +/- 7.1 for T; 1.8 +/- 3.2 for C; p = 0.08). After three months, a statistically significant decrease in the average percentage of sites with scores of two or three was demonstrated in the T group (0.7 +/- 2.4, T, p < 0.0001; 1.3 +/- 3.0, C, p < 0.25). The authors concluded that the application of a chlorhexidine varnish significantly improved the gingival health of T subjects for up to three months. A significant improvement in the gingival health could not be demonstrated in the C group.

Antiphospholipid syndrome in patients with cyanotic congenital heart disease

Patients with cyanotic congenital heart disease exhibit an increased incidence of thrombotic episodes and are frequently thrombocytopenic. We studied the sera of 15 patients with this type of heart malformation, searching for anticardiolipin antibodies. 3/15 had positive results. The three of them were adult females; two had thrombotic episodes and a false positive VDRL. Thus, cyanotic congenital heart disease may be another disease entity associated with the antiphospholipid syndrome.

[Acute pulmonary edema. The therapeutic approach]

The management of acute pulmonary edema remains an interesting challenge to the clinician. The early recognition of this frequent condition, based on clinical features, must lead to the institution of general measures of therapy that can save most patients; a delay or mistake in this early treatment is lethal. The subsequent treatment depends on the characterization of the etiology and the pathophysiological characteristics of each case. The authors present a review of the management of acute pulmonary edema for the general practitioner, which includes the general first line measures and also mention some therapeutic approaches, related to different etiologies, namely those requiring intensive care units.