Abstract P6-09-45: Long-term follow-up of early stage breast cancer patients with results of MammaPrint®, Oncotype DX® and MammoStrat® risk classification assays

Introduction: The use of genomic tests for the prediction of breast cancer recurrence is becoming more common. MammaPrint® (MP, Agendia Inc.) is a 70-gene microarray assay designed to assess the 10-year risk of recurrence in an untreated population that was not selected for ER/HER2 results. The Oncotype DX® Recurrence Score® (RS, Genomic Health, Inc.) is a 21-gene RT-PCR assay that is clinically validated to predict the 10-year risk of distant recurrence in ER+ patients treated with Tamoxifen. MammoStrat® (MS, Clarient, Inc.) is an IHC assay that uses 5 antibodies and has been validated in a similar population as RS. Several recent reports show that these assays classify patients differently with significant discordances for all risk groups (Shivers, et al., SABCS 2013; Denduluri, et al., ASCO Breast 2011; Poulet, et al., SABCS 2012; Schneider, et al., ASCO 2013). The present study is an analysis of long-term follow-up in a cohort of patients who have results for all three of these risk-stratifying assays side by side in the same samples.

Methods: Patients with ER+ N0-N1 early-stage breast cancer with an MP result obtained as part of their routine clinical care were identified at the University of South Florida (USF, N=65) and Morton Plant Hospital (N=83). After local IRB approval, slides and/or blocks were cut and de-identified at USF and sent to Genomic Health and Clarient for blinded testing. Clinicopathological features were also reviewed by 3 breast pathologists.

Results: 148 patients with an MP result had tissue available to send for RS and MS assays. These patients had a median age of 62 years; median tumor size 1.8 cm; 9% low grade, 59% intermediate grade and 32% high grade. In our previous analysis of this study, of 148 patients with MP results, 53% were low risk and 47% were high risk. Of 135 samples that yielded enough RNA to produce an RS result, 53% were low risk, 26% were intermediate risk and 21% were high risk. Of 129 samples that yielded an MS result, 44% were low risk, 28% were moderate risk and 28% were high risk. Of 121 patients with results for all 3 assays, only 22% were concordant for low risk and 9% were concordant for high risk across all 3 assays. Overall, 30% of cases showed a major discordance such as low risk for one assay and high risk for another. After median follow-up of 54 months, 9 patients have had a distant metastasis and/or 8 patients have died (11 patients total). One patient who had bone metastasis and died had been classified as low risk by all 3 assays. Three patients with distant metastases had a major discordance between assays, with two high risk and one low risk result. Seven patients were classified as high or intermediate/moderate risk by all 3 assays.

Conclusions: This direct comparison demonstrates that although the assays classify a large proportion of patients differently, the patients who ended up with a distant metastasis and/or died of breast cancer had been classified as high risk by at least two of the three assays. This study has important clinical implications since these assays are used to help make treatment decisions regarding which patients might benefit from chemotherapy.

Citation Format: Shivers SC, Russell S, Blumencrancz L, Mehindru A, Acs G, Ellis D, Vrcelj V, Zanchi A, Blumencrancz PW, Carter E, King J, Cox CE. Long-term follow-up of early stage breast cancer patients with results of MammaPrint®, Oncotype DX® and MammoStrat® risk classification assays [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-09-45.

[Renal aspects of sodium glucose cotransporter 2 inhibitors]

It has been known for centuries that the kidneys play a role in glucose homeostasis, yet the underlying tubular mechanisms have only been recently identified by studying patients with familial glucosuria. These insights have lead to the commercialization of a novel class of oral antidiabetic agents named gliflozines. Gliflozines induce renal glucosuria by blocking the Na-glucose cotransporter SGLT2, localized in the proximal tubule, and allow a reduction of 0.5 to 1% of glycated hemoglobin. They also diminish proximal sodium reabsorption, and reduce the glomerular hyperfiltration that is often seen in the early stages of diabetes. Preliminary data suggest that they may decrease blood pressure and have renoprotective effects. This article provides an overview of the role of kidneys in glucose homeostasis and the renal effects of SGLT2-inhibitors.

[Diabetes and end stage renal disease. Eight year progression in the Canton de Vaud, Switzerland]

Diabetic nephropathy is the first cause of endstage renal disease. The demographic expansion, the increase in the incidence of diabetes and the prolonged survival rates explain the steep increase observed these last 30 years. In the United States, improved treatment has brought to a decline in the incidence of end-stage renal disease in the diabetic population since the mid nineties. We examined the change in prevalence of diabetics on dialysis from 2001 and 2009 in the Canton de Vaud, Switzerland. The prevalence of diabetics on dialysis increased from 18% to 31% in dialysis centers and increased from 1.1/1000 to 1.9/1000 in the diabetic population. These are strong indicators that efforts are needed to improve the renal outcome of patients with diabetic nephropathy.

Effects of the peroxisome proliferator-activated receptor (PPAR)-gamma agonist pioglitazone on renal and hormonal responses to salt in diabetic and hypertensive individuals

AIMS/HYPOTHESIS

Glitazones are powerful insulin sensitisers prescribed for the treatment of type 2 diabetes. Their use is, however, associated with fluid retention and an increased risk of congestive heart failure. We previously demonstrated that pioglitazone increases proximal sodium reabsorption in healthy volunteers. This study examines the effects of pioglitazone on renal sodium handling in individuals prone to insulin resistance, i.e. those with diabetes and/or hypertension.

METHODS

In this double-blind randomised placebo-controlled four-way crossover study, we examined the effects of pioglitazone (45 mg daily during 6 weeks) or placebo on renal, systemic and hormonal responses to changes in sodium intake in 16 individuals, eight with type 2 diabetes and eight with hypertension.

RESULTS

Pioglitazone was associated with a rapid increase in body weight and an increase in diurnal proximal sodium reabsorption, without any change in renal haemodynamics or in the modulation of the renin-angiotensin aldosterone system to changes in salt intake. A compensatory increase in brain natriuretic peptide levels was observed. In spite of sodium retention, pioglitazone dissociated the blood-pressure response to salt and abolished salt sensitivity in salt-sensitive individuals.

CONCLUSIONS/INTERPRETATION

Pioglitazone increases diurnal proximal sodium retention in diabetic and hypertensive individuals. These effects cause fluid retention and may contribute to the increased incidence of congestive heart failure with glitazones.

TRIAL REGISTRATION

ClinicalTrial.gov NCT01090752

FUNDING

Hypertension Research Foundation Lausanne.

Deep Sedation in Paediatric MR: A Review of Our Case Histories

Sedation in paediatric MR is a necessary choice because very often we are dealing with uncooperative patients about to undergo lengthy examinations. The aim of this a retrospective study is to demonstrate that profound sedation with halogenated vapour Sevorane, together with specific systems for monitoring vital signs, is a safe and reliable technique. In accordance with current guidelines, it is considered essential to have an expert anaesthetist present in order to reduce the risk of incidents, which, in the case of difficulty in the airways, as seen in literature, could have fatal outcomes.

Activation of electrical triggers of atrial fibrillation in hyperthyroidism

CONTEXT

A shortening of the atrial refractory period has been considered as the main mechanism for the increased risk of atrial fibrillation in hyperthyroidism. However, other important factors may be involved.

OBJECTIVE

Our objective was to determine the activity of abnormal supraventricular electrical depolarizations in response to elevated thyroid hormones in patients without structural heart disease.

PATIENTS AND DESIGN

Twenty-eight patients (25 females, three males, mean age 43+/-11 yr) with newly diagnosed and untreated hyperthyroidism were enrolled in a prospective trial after exclusion of heart disease. Patients were followed up for 16 +/- 6 months and studied at baseline and 6 months after normalization of serum TSH levels.

MAIN OUTCOME MEASURES

The incidence of abnormal premature supraventricular depolarizations (SVPD) and the number of episodes of supraventricular tachycardia was defined as primary outcome measurements before the start of the study. In addition, heart rate oscillations (turbulence) after premature depolarizations and heart rate variability were compared at baseline and follow-up.

RESULTS

SVPDs decreased from 59 +/- 29 to 21 +/- 8 per 24 h (P = 0.003), very early SVPDs (so called P on T) decreased from 36 +/- 24 to 3 +/- 1 per 24 h (P < 0.0001), respectively, and nonsustained supraventricular tachycardias decreased from 22 +/- 11 to 0.5 +/- 0.2 per 24 h (P = 0.01) after normalization of serum thyrotropin levels. The hyperthyroid phase was characterized by an increased heart rate (93 +/- 14 vs. 79 +/- 8 beats/min, P < 0.0001) and a decreased turbulence slope (3.6 vs. 9.2, P = 0.003), consistent with decreased vagal tone. This was confirmed by a significant decrease of heart rate variability.

CONCLUSION

Hyperthyroidism is associated with an increased supraventricular ectopic activity in patients with normal hearts. The activation of these arrhythmogenic foci by elevated thyroid hormones may be an important causal link between hyperthyroidism and atrial fibrillation.

[Chronic kidney disease and antidiabetic treatment]

Diabetic nephropathy is the leading cause of chronic renal failure (CRF) in Europe. About fifty percent of diabetic subjects develop microalbuminuria, which progresses towards established diabetic nephropathy in one third of patients. The treatment of type 2 diabetes in a patient with CRF is a challenge for the general practitioner, because of the accumulation of drugs and/or specific metabolites. Sulfonylureas are associated with an increased risk of hypoglycaemia. Biguanides may exceptionally cause life-threatening lactic acidosis. Glitazones have an interesting profile since they decrease microalbuminuria and blood pressure. However, their safety is not well defined in the context of CRF In the case of severe CRF, only insulin and repaglinide can be recommended.

Antimicrobial susceptibility of Streptococcus pyogenes and Streptococcus pneumoniae: surveillance from 1993 to 2004 in Central Italy

The susceptibility of 1870 Streptococcus pyogenes and 1595 Streptococcus pneumoniae to macrolides and lincosamides has been monitored from 1993 to 2004 in Central Italy. Among S. pyogenes, 30.2% were erythromycin resistant; 18.5% were also resistant to josamycin and clindamycin (MLS phenotype). After an increasing erythromycin resistance rate in 1993-1997 (maximum 53.16%), a definite decrease was observed since 2001 with resistance rates always less than 30%. Thirty six percent of pneumococcal isolates were erythromycin-resistant, with minor temporal fluctuations; the MLS phenotype was the most prevalent overall (32.6%) and in individual years. S. pneumoniae strains were also tested for susceptibility to beta-lactams and other antimicrobial agents: 11.2% were penicillin non-susceptible, with a gradually increasing prevalence after 2001 (maximum rate 17.3% in 2004), 31.15% were resistant to tetracycline, 4.9% to chloramphenicol, 0.74% to rifampin. All pneumococcal isolates were susceptible to teicoplanin and 99.9% to ceftriaxone and ofloxacin.

Epidemiology of streptococcus group A in school aged children in Pemba

BACKGROUND

In Pemba (Zanzibar) all the risk factors which favour Group A Streptococci spreading, infections and late sequelae are present, though GAS epidemiology is unknown.

OBJECTIVE

To determine the prevalence of GAS pharyngeal carriers among school-aged-children.

DESIGN

Community-based cross sectional study, carried out at the end of the dry season (January-February 2001).

SETTING

Eight primary schools over the four Pemba districts were included in the study.

SUBJECTS AND METHODS

Two thousand two hundred and eighty six children aged 7-10 years were selected by random sampling and submitted to throat-swab after informed consent. Swabs were processed according to the "Lennette Manual of Clinical Microbiology" 7th Ed. Isolated were tested for antibiotic susceptibility toward penicillins, erythromycin, clindamycin, josamycin, cloramphenicol, levofloxacin, rifampin and tetracyclines.

RESULTS

Twenty seven point six percent of school-aged children harboured beta-haemolytic Streptococci in their pharynx; most of the isolates were serologically identified as non Group A streptococci group C and G represented more than 70% of all strains, 38.8% of whom were identified as group G; the prevalence of group A streptococci carriers among healthy children all over the island was 8.6%; group A streptococci isolates were sensitive to all the antibiotic tested, except tetracyclines, towards which 83.2% of strains were resistant.

CONCLUSION

This is the first research in the field of bacteriology carried out in Pemba. According to the epidemiology of group A streptococci and to the environmental and underlying factors which predispose to late group A streptococci sequelae, we suggest to consider antibiotic treatment for children presenting with sore throat with fever and swollen cervical lymphonodes without cough or coryza.

Staphylococcus aureus nasal carriage in the community: a survey from central Italy

Recently, concern has increased regarding the spread of methicillin-resistant Staphylococcus aureus (MRSA) in the community. We studied 812 subjects from central Italy to establish the rates of nasal carriage of S. aureus, and antibiotic susceptibility patterns, in the community. The prevalence of S. aureus nasal carriage was 30.5%. Only one subject, with predisposing risk factors for acquisition, was identified as carrier of MRSA (prevalence of 0.12%). The presence of MRSA in the community of our area still appears to be a rare event. Among methicillin-susceptible S. aureus (MSSA) isolates, a surprisingly high rate (18%) of resistance to rifampin was observed.

Testing mode of inheritance of a candidate mutation at a quantitative trait locus

Here is presented an approach to testing whether the effect of a candidate gene on a quantitative trait is dominant and for testing whether the effect is recessive. The approach uses parental genotype information in nuclear families to adjust for bias due to population admixture. The approach is applicable regardless of the nature of the sampling. The results of an application of the methods to a candidate mutation for diabetic nephropathy are used for illustration.

Risk of advanced diabetic nephropathy in type 1 diabetes is associated with endothelial nitric oxide synthase gene polymorphism

Risk of advanced diabetic nephropathy in type 1 diabetes is associated with endothelial nitric oxide synthase gene polymorphism.

BACKGROUND

Polymorphisms in the endothelial nitric oxide synthase gene (eNOS) may be implicated in the development of nephropathy in patients with type 1 or insulin-dependent diabetes mellitus (IDDM).

METHODS

Three groups of IDDM patients were selected to study this hypothesis: cases with advanced diabetic nephropathy (N = 78), cases with overt proteinuria but normal serum creatinine (N = 74), and controls with normoalbuminuria despite 15 years of diabetes (N = 195). Parents of 132 cases and 53 controls were also examined and were used for the transmission disequilibrium test, a family-based study design to test association.

RESULTS

We examined four eNOS polymorphisms, and two were associated with diabetic nephropathy in the case-control comparisons: a T to C substitution in the promoter at position -786 and the a-deletion/b-insertion in intron 4. For the former, the risk of developing advanced nephropathy was higher for C allele homozygotes than for the other two genotypes (odds ratio 2.8, 95% CI, 1.4 to 5.6). For the latter polymorphism, it was the a-deletion carriers that had the higher risk (odds ratio 2.3, 95% CI, 1.3 to 4.0) in comparison with noncarriers. Both polymorphisms were analyzed together as haplotypes in a family-based study using the transmission disequilibrium test. The C/a-deletion haplotype was transmitted from heterozygous parents to cases with advanced diabetic nephropathy with a significantly higher frequency than expected (P = 0.004).

CONCLUSION

The findings of the case-control and family-based studies demonstrate clearly that DNA sequence differences in eNOS influence the risk of advanced nephropathy in type 1 diabetes.

Mantle exhumation along the Tirich Mir Fault Zone, NW Pakistan: pre-mid-Cretaceous accretion of the Karakoram terrane to the Asian margin

The left-lateral strike-slip Tirich Mir Fault, Chitral, NW Pakistan, is associated with a belt of periodotites, metagabbros and gneisses named the Tirich Boundary Zone (TBZ), separating the Late Palaeozoic-Mesozoic units of the East Hindu Kush from the Palaeozoic successions of the Karakoram block. These rocks were metamorphosed up to upper amphibolite facies conditions, followed by a greenschist facies overprinting, and then thrust on to very low grade metasediments; they were finally intruded at shallow levels by the mid-Cretaceous Tirich Mir pluton. Ultramafic rocks along the fault zone include well-preserved spinel lherzolites and harzburgites (Tirich Gol, Barum valley, Arkari Gol), whereas schistose serpentinites occur in the Rich Gol. Whole-rock analyses and mineral chemistry of olivine, clinopyroxene, orthopyroxene and spinel from these peridotites show a depleted signature. Microstructural and petrological features suggest a mantle origin for these ultramafic bodies, which equilibrated at temperatures ranging from 1000–1100°C. Periodotites are faulted against partially metamorphosed igneous bodies including hornblende-gabbros, hornblende cumulates and quartz-diorites. Metamorphic rocks of the TBZ, which lay south of the ultramafic-mafic complex, include quartzites, amphibolites, garnet-sillimanite (± kyanite ± K-feldspar)-biotite gneisses and mica schists, locally displaying migmatitic textures.

A sub-continental character of the peridotites indicated by low temperatures of equilibration and by the presence of a deep crustal sequence. These characters along with the absence of an ophiolitic sequence may suggest that the TBZ represents a fragmented crust-mantle boundary developed along a zone of attenuated continental crust. The TBZ is interpreted as a sheared lithospheric section of a Jurassic-Early Cretaceous orogenic complex, formed as a consequence of the accretion of the Karakoram terrane to the southern side of the Pamir belts, which were progressively accreted to the Asian margin.

Patterns of macrolide resistance determinants among community-acquired Streptococcus pneumoniae isolates over a 5-year period of decreased macrolide susceptibility rates

Erythromycin resistance rates were found to be increased, from 7.1 in 1993 to 32.8% in 1997, among community-acquired Streptococcus pneumoniae isolates from the Siena area of central Italy. Most of the erythromycin-resistant isolates carried ermAM determinants and were also resistant to josamycin and clindamycin, whereas a minority (5.8%) carried mefA determinants and remained susceptible to the latter drugs.

Aortic connexin43 is decreased during hypertension induced by inhibition of nitric oxide synthase

Connexin43 (Cx43), the predominant gap junction protein in vessels and heart, is involved in the control of cell-to-cell communication and is thought to modulate the contractility of the vascular wall and the electrical coupling of cardiac myocytes. We have investigated the effects of arterial hypertension induced by inhibition of nitric oxide synthase on the expression of Cx43 in aorta and heart as well as on the distensibility of the carotid artery. Administration of 0.4 g/L NG-nitro-L-arginine methyl ester (L-NAME) to rats in their drinking water for 4 weeks increased intra-arterial mean blood pressure, wall thickness of aorta and carotid artery (25%), and heart weight (17%). Analysis of heart mRNA demonstrated increased expression of the fetal skeletal alpha-actin and of atrial natriuretic peptide but not of Cx43. In contrast, Cx43 mRNA and protein were decreased by 50% in the aortas of L-NAME-treated rats that did not show increased carotid distensibility. Because these data contrasted with those obtained in the 2-kidney, 1 clip model of rat hypertension, which is characterized by increased arterial distensibility and Cx43 expression in aorta, we investigated by Western blot analysis the posttranslational modifications of Cx43. We found that Cx43 was more phosphorylated in the aorta of 2-kidney, 1 clip rats than in that of L-NAME or control rats, which indicated a differential regulation of Cx43 in different models of hypertension. The data suggest that the cell-to-cell communication mediated by Cx43 channels may help regulate the elasticity of the vascular wall.

Identification of Aeromonas strains of clinical origin with atypical phenotypical profiles

A total of 47 strains of Aereomonas isolated from patients with gastroenteritis was analyzed for 40 phenotypical characters and for evaluating the numeric taxonomy based on 27 discriminatory tests. It was proved that the clinical isolates showed a relative phenotypical distance and the groups of strains that had atypical profiles were compared with the type species by the present identification schemes.

Differences in the mechanical properties of the rat carotid artery in vivo, in situ, and in vitro

The elastic properties of carotid arteries of spontaneously hypertensive rats (SHR) and normotensive controls (Wistar-Kyoto rats [WKY]) were examined in vivo, in situ, and in vitro. The changes of internal diameter were measured with a high-resolution A-mode echo-tracking device simultaneously with the intra-arterial pressure at the carotid. The internal diameter at mean arterial blood pressure (MBP) was substantially smaller in vitro than in vivo in SHR (-33.8%) and WKY (-48.3%). The arterial distensibility was lower in vitro in all arteries compared with in vivo conditions (SHR, -30.1%; WKY, -60.4%; at MBP) despite a reduced incremental elastic modulus in vitro (SHR, -56.9%; WKY, -45.1%; at MBP). However, the in vitro and in vivo measurements show consistent elastic behavior of the carotid arteries between both strains of rats. Carotid arteries from WKY were also examined in situ. Although no significant reduction in internal diameter could be observed in situ, distensibility was dramatically decreased (-87% at MBP). These results emphasize the importance of considering the original vascular geometry when determining elastic properties of arteries. We conclude that experimental conditions are likely to be a critical determinant for the assessment of the mechanical properties of conduit vessels.

Unusual species of campylobacters isolated in the Siena Tuscany area, Italy

From January 1989 to December 1990, stool samples from 288 children with enteritis were examined for the presence of unusual campylobacters which represented about 20% of all campylobacteria isolated when the filtration technique was used. The isolation percentage was the following: C. jejuni ss. jejuni 6.9%; C. coli 2%; C. jejuni ss. doylei, C. upsaliensis and C. concisus each 0.7%. The atypical Campylobacter isolates were examined for their virulence characteristics. Toxin profiles based on cytotonic, cytotoxic and cytolethal distending factors were determined after analysis responses in Vero, CHO and HeLa cells. Adhesivity and invasivity tests were performed on Intestine 407 cells. No strain was cytotoxic. C. jejuni ss. doylei and C. concisus induced an elongation of CHO cells (a cytotonic-like effect). C. upsaliensis strains provoked a cytolethal distending effect. No strain adhered to cells in vitro. Our results suggest that the filtration technique is excellent for the isolation of atypical campylobacters and indicate that the unusual Campylobacter isolates could be potentially virulent.

Age-related changes of the mechanical properties of the carotid artery in spontaneously hypertensive rats

BACKGROUND

We had previously demonstrated that the distensibility of the carotid artery in spontaneously hypertensive rats (SHR) aged 18 weeks does not differ from that of the carotid artery in normotensive animals for common pressure levels, despite vascular hypertrophy in SHR.

OBJECTIVE

To examine the time-course effects of hypertension on the geometry and the mechanical properties of the carotid artery in SHR.

METHODS

The mechanical behavior of the carotid arteries of anesthetized SHR, stroke-prone SHR (SHRSP), and Wistar-Kyoto (WKY) rats aged 4, 8, 12, 16, and 32 weeks was examined by simultaneously measuring the internal diameter with an A-mode ultrasonic echo-tracking device and the intra-arterial pressure with a computerized data-acquisition system. Histometric measurements of the carotid artery were performed after death of rats.

RESULTS

Blood pressure increased with time in rats of the two genetic hypertensive models. However, it rose earlier and to higher levels in the SHRSP. Cardiac hypertrophy was comparable in the two hypertensive groups whereas vascular hypertrophy was less pronounced in the SHRSP than it was in the SHR. There was an age-related decrease in arterial distensibility in rats of all groups that was more pronounced in the SHRSP than it was in the SHR compared with that in WKY rats (decreases of 57 and 36%, respectively, versus WKY rats aged 32 weeks; P < 0.05). For rats of all ages studied, although aging affected differently the vascular properties of the distinct animal strains, arterial distensibility was increased in the SHR and SHRSP compared with that in control animals for similar blood pressure levels, implying a rightward shift of the distensibility-pressure curves in the two hypertensive models. However, there was a significant reduction in arterial distensibility in rats of the two hypertensive strains at their respective mean blood pressures, compared with that in control animals.

Species, biotype and serogroup of Campylobacter spp. isolated from children with diarrhoea over a ten-year period

From 1981 to 1990, stool samples from 6403 gastroenteritis cases were examined for the presence of campylobacters as well as Salmonella, Shigella, Aeromonas species and Yersinia enterocolitica. The percentages of isolation were the following: campylobacters 10.8 (86.1% of isolates were C. jejuni and 13.9% were C. coli), Salmonella spp. 8.4, Aeromonas spp 1.4, Yersinia enterocolitica 0.3. Shigella spp. were isolated only occasionally. Predominant biotypes of campylobacters were C. jejuni I (69.5%), C. jejuni II (29.5%) and C. coli I (92.7%). The six most common LIO serogroups-36; 4; 1; 28.53; 11; 2-accounted for 50% ca. of typable strains. Campylobacters are the most common etiological agent of bacterial enteritis in children living in this area of Tuscany. The species and serogroup determination can be useful from an epidemiological point of view.

Time course changes of the mechanical properties of the carotid artery in renal hypertensive rats

Distensibility of the carotid artery is not altered 2 weeks after renal artery clipping despite adaptive vascular hypertrophy related to hypertension. The purpose of this study was to assess arterial wall behavior with hypertension persisting for a longer period. Male Wistar rats were examined 1, 5, 9, and 24 weeks after renal artery clipping (two-kidney, one clip renal hypertension; n = 40) or after sham operation (n = 39). Mean blood pressure increased significantly to 132 +/- 4, 143 +/- 4, 153 +/- 4, and 144 +/- 4 versus 98 +/- 2, 107 +/- 2, 115 +/- 3, and 108 +/- 3 mm Hg, respectively, in 1-, 5-, 9-, and 24-week hypertensive rats and age-matched controls. Cardiac and vascular hypertrophy increased in parallel and were correlated to mean blood pressure. Wall stress at mean blood pressure did not differ between the hypertensive and normotensive groups (3.79 +/- 0.24, 4.60 +/- 0.34, 4.49 +/- 0.27, and 4.14 +/- 0.28 versus 3.15 +/- 0.12, 4.14 +/- 0.25, 4.80 +/- 0.28, and 4.69 +/- 0.32 10(3) dyne/cm2, respectively, in 1-, 5-, 9-, and 24-week hypertensive rats and age-matched controls). Distensibility-pressure data from the two groups fell on a common curve for all study periods. The intrinsic properties of the wall constituents were similar in controls and hypertensive rats at 1 and 5 weeks. However, the arteries became stiffer in the 9- and 24-week hypertensive rats, as illustrated by a shift to higher levels of the incremental elastic modulus-stress curve. Wall stress remains constant at mean blood pressure as a result of the increase in wall tissue mass. With time, even though the distensibility-pressure curve is not shifted downward, the thickened wall becomes stiffer in the hypertensive rats, which may predispose them to accelerated alterations of the wall material.

Susceptibility of macrolide and beta-lactam antibiotics of Streptococcus pyogenes strains isolated over a four-year period in central Italy

In vitro susceptibility to erythromycin, azithromycin, penicillin G, ceftriaxone and ceftibuten was investigated in 190 Streptococcus pyogenes strains isolated over a 4-year period (1991-1994) from patients attending a university hospital located in central Italy. The rate of susceptibility to macrolide antibiotics of the S. pyogenes strains showed a progressive decrease (from 90.3% in 1991 to 79.5% in 1994), while all strains were susceptible to the three beta-lactam antibiotics. Owing to the reduced prevalence of macrolide-susceptible S. pyogenes strains, in vitro susceptibility testing of streptococcal isolates appears to be always necessary before starting a macrolide-based chemotherapy. Concerning beta-lactams, ceftriaxone presented minimum inhibitory concentrations (MIC) always equal to or lower than those of penicillin G, while the oral long-acting cephalosporin, ceftibuten, had MICs higher than those of the other beta-lactams, although in the susceptible range. Results of in vitro susceptibility testing are discussed in relation to their implications for antimicrobial chemotherapy of S. pyogenes infections.

Endothelial function of the mesenteric arteriole and mechanical behaviour of the carotid artery in rats with insulin resistance and hypercholesterolaemia

OBJECTIVE

To examine whether insulin resistance and hypercholesterolaemia in obese Zucker rats are associated with a modification of the mechanical behaviour of a conductance (carotid) artery and with an altered endothelium-dependent response to acetylcholine of a small resistance (mesenteric) artery.

DESIGN

Male obese Zucker rats, 6-8 months old, were compared with age-matched lean heterozygous and control Zucker rats.

METHODS

The mechanical behaviour of the carotid artery was examined in anaesthetized rats by simultaneously monitoring the internal diameter with an A-mode ultrasonic echo-tracking device and the intra-arterial pressure with a computerized data-acquisition system. Furthermore, histometric measurements of the carotid artery were carried out after death. The response to acetylcholine was examined in vitro with a Mulvany dual myograph on precontracted isolated segments of the third-generation mesenteric artery.

RESULTS

Obese Zucker rats exhibited high plasma insulin and cholesterol levels. Blood pressure was the same in the obese and control animals. There was no hypertrophy or change in the mechanical behaviour of the carotid arterial wall. Heart weight was slightly higher in the obese rats than in the controls, but smaller in relation to body weight. The relaxation to acetylcholine was significantly attenuated in isolated small mesenteric arteries obtained from the obese strain.

CONCLUSION

Hyperinsulinaemia and hypercholesterolaemia in obese Zucker rats are associated with an abnormal response to acetylcholine in the mesenteric arterioles. This metabolic state does not, however, alter the mechanical behaviour or the geometry of the carotid artery.

Renal haemodynamic and protective effects of calcium antagonists in hypertension

In recent years, the ability of the various antihypertensive drugs to provide renal protection has been the subject of increased attention. Whether calcium antagonists prevent or reduce the rate of progression of renal damage is still a matter of controversy. This paper reviews the findings of recent animal and human studies on the haemodynamic and renal protective effects of calcium antagonists. These agents preferentially vasodilate afferent arterioles, leading to an increase in renal blood flow and glomerular filtration rate. These effects are more pronounced in hypertensive patients than in normotensive subjects and persist even when renal function is impaired. In animal models of chronic renal failure, calcium antagonists can reduce glomerulosclerosis. However, the mechanisms involved in their renal protective effect appear to be different from those of angiotensin converting enzyme (ACE) inhibitors as they do not reduce intraglomerular pressure. Renal failure caused by vasoconstriction related to radiocontrast agents or cyclosporine can be partly prevented by the administration of a calcium antagonist. Furthermore, in patients with renal artery stenosis, calcium antagonists reduce blood pressure with less renal blood flow impairment than ACE inhibitors. Preliminary clinical studies suggest that verapamil or diltiazem may reduce proteinuria in hypertensive diabetic patients. Whether these compounds can also retard the progression of renal failure in these patients remains to be established with larger trials.

Chronic nitric oxide synthase inhibition and carotid artery distensibility in renal hypertensive rats

The goal of the present study was to examine the viscoelastic properties of the carotid artery in genetically identical rats exposed to similar levels of blood pressure sustained by different mechanisms. Eight-week old male Wistar rats were examined 2 weeks after renal artery clipping (two-kidney, one clip [2K1C] Goldblatt rats, n = 53) or sham operation (n = 49). One half of the 2K1C and sham rats received the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 1.48 mmol/L) in their drinking water for 2 weeks after the surgical procedure. Mean blood pressure increased significantly in the 2K1C-water (182 mm Hg), 2K1C-L-NAME (197 mm Hg), and sham-L-NAME (170 mm Hg) rats compared with the sham-water rats (127 mm Hg). Plasma renin activity was not altered by L-NAME but significantly enhanced after renal artery clipping. A significant and similar increase in the cross-sectional area of the carotid artery was observed in L-NAME and vehicle-treated 2K1C rats. L-NAME per se did not modify cross-sectional area in the sham rats. There was a significant upward shift of the distensibility-pressure curve in the L-NAME- and vehicle-treated 2K1C rats compared with the sham-L-NAME rats. L-NAME treatment did not alter the distensibility-pressure curve in the 2K1C rats. These results demonstrate that the mechanisms responsible for artery wall hypertrophy in renovascular hypertension are accompanied by an increase in arterial distensibility that is not dependent on the synthesis of nitric oxide.

Vascular acetylcholine response during chronic NO synthase inhibition: in vivo versus in vitro

OBJECTIVE

The aim of this study was to compare the response to NO-mediated vasodilators in vivo and in vitro during chronic NO synthase inhibition.

METHODS

NG-Nitro-L-arginine-methyl ester (L-NAME, 0.4 g/l) or vehicle was administered in the drinking water for 6 weeks to male Wistar rats weighing 220-240 g. The effect of acetylcholine and sodium nitroprusside was examined in vivo, on systemic blood pressure and heart rate and in vitro, on the precontracted isolated mesenteric artery. The in vivo response to both vasodilators was examined in awake rats monitored by an indwelling catheter in the femoral artery. Isolated segments of the third-generation mesenteric artery were examined in vitro with a Mulvany dual myograph after precontraction with noradrenaline.

RESULTS

In isolated mesenteric arteries obtained from rats chronically treated with L-NAME, the initial relaxant response to acetylcholine was significantly decreased whereas that to sodium nitroprusside was enhanced. A late acetylcholine-induced contractile response was present and abolished by indomethacin. In vivo, the hypotensive action of sodium nitroprusside was also enhanced in the L-NAME-treated rats. Acetylcholine reduced blood pressure in the L-NAME-treated hypertensive animals more than in normotensive controls, but less than in control rats infused intravenously with noradrenaline at a dose increasing their blood pressure to hypertensive levels.

CONCLUSIONS

The NO-mediated vasodilation induced by acetylcholine is attenuated during chronic NO synthase inhibition, both in vivo and in vitro. The blunted hypotensive response to acetylcholine can be demonstrated only if blood pressure of control rats is acutely increased to hypertensive levels.

Effects of chronic NO synthase inhibition in rats on renin-angiotensin system and sympathetic nervous system

This study was designed to assess the role of renin and of the sympathoadrenal system in the maintenance of the hypertension induced by chronic nitric oxide synthase (NOS) inhibition in rats kept on a normal (RS) or a low-sodium (LS) diet. With the administration of NG-nitro-L-arginine methyl ester (L-NAME) in drinking water (0.4 milligrams) for 6 wk, mean intra-arterial blood pressure rose to a similar extent to 201 mmHg in the RS and 184 mmHg in the LS animals. Simultaneously, plasma norepinephrine was increased to 838 and 527 pg/ml and epinephrine to 2,041 and 1,341 pg/ml in RS and LS, respectively. Plasma neuropeptide Y levels did not change. Plasma renin activity rose to 21 ng.ml-1.h-1 in RS but remained at 44 ng.ml-1.h-1 in the LS. Both losartan (10 mg/kg) and phentolamine (0.1 mg/kg) intravenous bolus injections reduced blood pressure considerably in the L-NAME hypertensive animals. Whole brain NOS activity was reduced by 84%. Hypertension induced by chronic NOS inhibition in LS as well as in RS fed rats seems to be sustained by an interaction of several mechanisms, including the activation of the sympathetic nervous system and the renin-angiotensin system.

Distribution of cphA or related carbapenemase-encoding genes and production of carbapenemase activity in members of the genus Aeromonas

The prevalence of the cphA gene or related carbapenemase-encoding genes was investigated in 114 Aeromonas strains belonging to the six species of major clinical interest. A species-related distribution of cphA-related sequences was observed. Similar sequences were found in A. hydrophila, A. veronii bv. sobria, A. veronii bv. veronii, and A. jandaei, but not in A. caviae, A. trota, or A. schubertii. However, a single A. caviae strain (of 62 tested) was found carrying cphA-related sequences, suggesting the possibility of the horizontal transfer of this gene to species which normally do not carry it. Production of carbapenemase activity was detectable in 83% of the hybridization-positive strains but in none of the hybridization-negative ones. When it was present, carbapenemase activity was always inhibitable by EDTA. Either carbapenemase-producing or not, Aeromonas strains appeared to be susceptible to imipenem when in vitro susceptibility testing was performed with inocula of conventional size (10(5) CFU), for which MICs were always < or = 1 microgram/ml. With a larger inoculum (10(8) CFU), the MICs for carbapenemase-negative strains always remained < or = 1 microgram/ml, while those for carbapenemase-producing strains were always > or = 4 micrograms/ml, being usually higher than the breakpoint for susceptibility. The present results indicate that the production of metallocarbapenemase activity, apparently encoded by cphA homologs, is widespread among some of the Aeromonas species of clinical interest (A. hydrophila, A. veronii bv. sobria, A. veronii bv. veronii, and A. jandaei) and that imipenem MICs for carbapenemase-producing strains are subjected to a relevant inoculum size effect.

Antibiotic susceptibility of 206 Haemophilus influenzae isolates collected from children in central Italy

Susceptibility of 206 H. influenzae isolates was evaluated by disk diffusion method for 11 antimicrobial agents. No isolates were found to be resistant to third-generation cephalosporins, amoxicillin+clavulanic acid, gentamicin and ciprofloxacin. Four untypable isolates (1.9%) were beta-lactamase producing ampicillin-resistant; one of these was also resistant to chloramphenicol. The rate of resistance against rifampin was 0.5 percent.

Angiotensin-converting enzyme inhibition by hydroxamic zinc-binding idrapril in humans

The new angiotensin-converting enzyme (ACE) inhibitor idrapril acts by binding the catalytically important zinc ion to a hydroxamic group. We investigated its pharmacodynamic and pharmacokinetic properties in 8 healthy men: Increasing doses of 1, 5, and 25 mg idrapril as well as placebo or 5 mg captopril were administered intravenously (i.v.) at 1-week intervals. Six of the subjects received 100 mg idrapril orally (p.o.) last, and two ingested oral placebo as a double-blind control. Blood pressure (BP) and heart rate (HR) remained unchanged. No serious side effects were observed. ACE inhibition in vivo was evaluated by changes in the ratio of specifically measured plasma angiotensin II (AngII) and AngI concentrations determined by high-performance liquid chromatography/radioimmunoassay (HPLC/RIA) techniques. Plasma ACE activity in vitro was estimated by radioenzymatic assay; it was suppressed by > or = 93% at 15 min after injection of 25 mg idrapril or 5 mg captopril and by 96% 2 h after idrapril intake. Mean AngII levels were decreased dose dependently at 15 min after idrapril injections. At the same time, plasma renin activity (PRA) and AngI increased according to the doses. The AngII/AngI ratio was clearly related to plasma idrapril levels (r = -0.88, n = 60). Oral idrapril inhibited ACE maximally at 1-4 h after dosing, when < 7% of initial ACE activity was observed in vitro and in vivo. Idrapril is a safe and efficient ACE inhibitor in human subjects. It is well absorbed orally. Besides having a slightly slower onset of action, idrapril has pharmacodynamic effects comparable to those of captopril.

Anaphylactoid purpura like vasculitis following fibrinolytic therapy: role of the immune response to streptokinase

We report the case of a patient who presented with a clinical picture of serum sickness with some characteristics of anaphylactoid purpura (Henoch-Schönlein purpura) five days after receiving streptokinase as a treatment for myocardial infarction. The appearance of Henoch-Schönlein like vasculitis after streptokinase treatment was particularly intriguing in view of the common association of streptococcus infection with this type of vasculitis. The production of streptokinase specific IgG and IgA antibodies was studied in the patient and compared with six controls treated with identical doses of streptokinase without adverse effects. A more rapid increase of streptokinase specific IgA was detected in the patient, with a significant higher amount of streptokinase specific IgA and IgG after six days of treatment. These results suggest that different kinetics could induce a precipitation of the immune complexes responsible for vasculitis. However, we cannot exclude that the IgA found in the vessel walls was only an "innocent bystander" deposited as a secondary event.

Detection of the Vibrio cholerae heat-stable enterotoxin gene by polymerase chain reaction

A polymerase chain reaction assay was developed for detection of the Vibrio cholerae heat-stable enterotoxin gene (sto). The assay is based on two oligonucleotide primers suitable for amplification of the entire sto open reading frame. Reaction conditions were defined to obtain optimal results in terms of specificity and sensitivity. Under these conditions the assay was highly sensitive and enabled good results to be obtained using, as a template, crude DNA preparations from single bacterial colonies. A rapid protocol for direct sequence analysis of the amplification product, which may be used in combination with the PCR assay to confirm the product identity and analyse sequence polymorphisms within the sto gene, was also developed. Twenty-two V. cholerae non-O1 isolates from sporadic cases of V. cholerae non-O1-associated gastroenteritis from Cuba were analysed by this PCR assay. Four strains (18.2%) were found to carry the sto gene. The prevalence of V. cholerae non-O1 strains carrying the sto gene among clinical isolates is higher than that reported for other geographical areas, except in the case of epidemics.

Genomic DNA fingerprints and phenotypic characteristics of serotype B Haemophilus influenzae isolates from Italy

Three different restriction enzymes (PstI, EcoRI, SspI) were used to analyze the total genomic DNA fingerprints of 52 Haemophilus influenzae type b (Hib) isolates collected between 1982 and 1992 from patients and carriers in central-northern Italy. The same isolates were also characterized by biotyping and antimicrobial agent susceptibility typing. In addition, 13 Hib reference strains from Sweden and the Netherlands were subjected to DNA fingerprinting and compared to Italian isolates. Both genotypic and phenotypic analysis revealed low variability among the Italian study isolates. Most were biotype I and all study isolates but one were susceptible to ampicillin, chloramphenicol, rifampin, third-generation cephalosporins and cotrimoxazole. Among the 52 Italian isolates, 3 distinct DNA patterns were identified, and 88.5% of study strains belonged to the same DNA group. There was sharing of the predominant DNA profile among isolates cultured in different years from different geographical areas and different invasive, respiratory and surface infections. However, another DNA pattern was only found in carrier isolates and in one surface infection isolate. Comparison by DNA fingerprinting showed that the majority of Italian isolates were closely related to most of the analyzed Swedish and Dutch reference strains, previously shown by other techniques to be predominant in those areas. This finding provides additional support for the hypothesis that there may be a dominant European Hib clone. The results show that DNA fingerprinting is a reliable method for Hib characterization and may be a useful additional epidemiological tool for this microorganism.

Two cases of Campylobacter mucosalis enteritis in children

Two cases of Campylobacter mucosalis enteritis in children are reported. The patients recovered without antimicrobial therapy. Strains were isolated only by the feces filtration technique. In one child, bactericidal antibodies to the homologous strain were detected in a convalescent-phase serum sample. C. mucosalis should be considered a primary intestinal pathogen.

Molecular epidemiology of nasopharyngeal corynebacteria in healthy adults from an area where diphtheria vaccination has been extensively practiced

In addition to conventional biochemical tests, a DNA probe specific for Corynebacterium diphtheriae was used to characterize 53 cystinase-positive and urease-negative corynebacteria strains isolated from pharyngeal and nasal swabs obtained from 515 healthy adults living in an urban area of central Italy. No Corynebacterium diphtheriae strain was found. Six "atypical" strains were isolated, which could not be classified in any of the species so far defined in the Corynebacterium genus. These strains appeared to be biochemically close to Corynebacterium pseudodiphtheriticum and genetically close to Corynebacterium diphtheriae, since their DNAs strongly hybridized, under relatively low stringency conditions, with a Corynebacterium diphtheriae-specific probe and since insertion sequences which are usually found in Corynebacterium diphtheriae genomes were also found to be present in their genomes. No one of these six strains was either toxigenic or susceptible to lysogenization by beta-corynephage carrying the tox gene. Therefore, they do not seem to have any epidemiological relevance as possible hosts for beta-phages.

Immunity to diphtheria in a sample of adult population from central Italy

A sample of 643 healthy subjects from central Italy aged 20 to 80, were screened for diphtheria antitoxin. Serum diphtheria antitoxin was assayed by a new passive haemagglutination technique using turkey red blood cells sensitized with diphtheria toxoid, after having performed a correlation study between this technique and the reference in vivo neutralization test. Of the studied population 26.7% showed a lack of serum antitoxin titres considered to be protective. The rate of susceptible subjects increased with age, showing the highest value (38.9%) in the sixth decade of age. Males proved less protected than females; 53.2% of the male population aged 50-59 were lacking a protective anti-diphtheria immunity. On the basis of present results, a periodical revaccination of the entire adult population with reduced doses of diphtheria toxoid would be advisable.

Rubella epidemiology over a 14-year period in Siena (Italy): a retrospective serological survey

A retrospective rubella serological survey spanning a 14-year period (1973-1986) was carried out on 5,726 subjects (2,339 diseased patients and 3,387 healthy females) of various ages and mostly living in the town of Siena or in its surroundings. Rubella antibodies were assayed by a haemagglutination-inhibition technique. The infection rate, as inferred from the analysis of the seropositivity rate according to age, peaked in the 6 to 10 year age group and was apparently very low in subjects aged over 30. The overall seropositivity rate of healthy females of childbearing age was 88.4%. Notwithstanding the fact that rubella vaccination has been recommended for all school-girls since 1973, no significant difference was noticed between the seropositivity rates of healthy females aged 18-23 observed in the period 1973-78 (i.e. before the first immunized subjects reached this age group) and in the period 1981-86 (i.e. when this age group had already been included among the first vaccinees). Serological diagnosis of acute rubella infection was achieved in 44 (1.9%) of the 2,339 diseased patients. Most diagnoses occurred in spring months.

Specific antibody patterns over a two-year period after rubella immunization with RA 27/3 live attenuated vaccine

Screening for rubella antibodies was carried out on 1557 schoolgirls aged 9-20. Of seronegative subjects 70% (442/631) were immunized with RA 27/3 rubella vaccine and some of the vaccinees underwent a serological and clinical follow-up over a two year period. Adverse reactions occurred in 27% of vaccinees, usually 1-2 weeks after immunization; late reactions were never observed. The vaccine-induced seroconversion rate evaluated at 4-5 weeks after immunization was 99.7%. Both one and two years after immunization the seropositivity rate of vaccinees was 100%. The maximum geometric mean antibody titre (GMT) was observed at 4-5 weeks after vaccination and a significant GMT decrease was evident on both the following annual controls. Specific antibody patterns in vaccinees were highly variable and in a small number of subjects a remarkable antibody titre decrease was noticed.