Phase II study investigating the efficacy and safety of glesatinib (MGCD265) in patients with advanced NSCLC containing MET activating alterations.

OBJECTIVES: Dysregulated signaling by mesenchymal epithelial transition factor (MET) and heightened AXL activation are implicated in the pathogenesis of non-small cell lung cancer (NSCLC). Glesatinib (MGCD265) is an investigational, oral inhibitor of MET and AXL. MATERIALS AND METHODS: This open-label, Phase II study investigated glesatinib (free-base suspension [FBS] capsule 1050 mg BID or spray-dried dispersion [SDD] tablet 750 mg BID) in patients with advanced, previously treated NSCLC across four cohorts grouped according to presence of MET activating mutations or amplification in tumor or ctDNA. The primary endpoint was objective response rate (ORR). RESULTS: Sixty-eight patients were enrolled: n = 28 and n = 8 with MET exon 14 skipping mutations in tumor tissue and ctDNA, respectively, and n = 20 and n = 12 with MET gene amplification in tumor tissue and ctDNA, respectively. Overall, ORR was 11.8 %, median progression-free survival was 4.0 months, and median overall survival was 7.0 months. Among patients with MET activating mutations, ORR was 10.7 % with tumor testing and 25.0 % with ctDNA testing. For MET amplification, responses were observed only in patients enrolled by tumor testing (ORR 15.0 %). Diarrhea (82.4 %), nausea (50.0 %), increased alanine aminotransferase (41.2 %), fatigue (38.2 %), and increased aspartate aminotransferase (36.8 %) were the most frequent adverse events assessed as related to study medication. Glesatinib exposure was similar with the SDD tablet and FBS capsule formulations. The study was terminated early by the sponsor due to modest clinical activity. CONCLUSIONS: Glesatinib had an acceptable safety profile in patients with advanced, pre-treated NSCLC with MET activating alterations. Modest clinical activity was observed, which likely reflects suboptimal drug bioavailability suggested by previously reported Phase I data, and pharmacodynamic findings of lower than anticipated increases in circulating soluble shed MET ectodomain (s-MET).

Mocetinostat in Combination With Durvalumab for Patients With Advanced NSCLC: Results From a Phase I/II Study.

BACKGROUND: Histone deacetylase (HDAC) inhibitors have potential to augment the effectiveness of immune checkpoint inhibitors and overcome treatment resistance. This dose-escalation/expansion study (NCT02805660) investigated mocetinostat (class I/IV HDAC inhibitor) plus durvalumab in patients with advanced non-small cell lung cancer (NSCLC) across cohorts defined by tumor programmed death-ligand 1 (PD-L1) expression and prior experience with anti-programmed cell death protein-1 (anti-PD-1) or anti-PD-L1 regimens. PATIENTS AND METHODS: Sequential cohorts of patients with solid tumors received mocetinostat (starting dose: 50 mg TIW) plus durvalumab at a standard dose (1500 mg Q4W) to determine the recommended phase II dose (RP2D: phase I primary endpoint), based on the observed safety profile. RP2D was administered to patients with advanced NSCLC across 4 cohorts grouped by tumor PD-L1 expression (none or low/high) and prior experience with anti-PD-L1 /anti-PD-1 agents (naïve, clinical benefit: yes/no). The phase II primary endpoint was objective response rate (ORR, RECIST v1.1). RESULTS: Eighty-three patients were enrolled (phase I [n = 20], phase II [n = 63]). RP2D was mocetinostat 70 mg TIW plus durvalumab. ORR was 11.5% across the phase II cohorts, and responses were durable (median 329 days). Clinical activity was observed in NSCLC patients with disease refractory to prior checkpoint inhibitor treatment: ORR 23.1%. Across all patients, fatigue (41%), nausea (40%), and diarrhea (31%) were the most frequent treatment-related adverse events. CONCLUSION: Mocetinostat 70 mg TIW plus durvalumab at the standard dose was generally well tolerated. Clinical activity was observed in patients with NSCLC unresponsive to prior anti-PD-(L)1 therapy.

Effect of tesamorelin in people with HIV with and without dorsocervical fat: Post hoc analysis of phase III double-blind placebo-controlled trial.

Tesamorelin, a synthetic growth hormone-releasing hormone, is indicated for the reduction of visceral adipose tissue (VAT) in people with HIV. Here, we performed a post hoc analysis of participants receiving tesamorelin for 26 weeks in a phase III clinical trial. Efficacy data were compared between individuals with and without dorsocervical fat, stratified by tesamorelin response. Among tesamorelin responders, VAT and waist circumference (WC) decreased in both dorsocervical fat groups and did not statistically differ (VAT P = 0.657, WC P = 0.093). These data demonstrate that tesamorelin is equally effective and should be considered in the treatment of excess VAT regardless of the presence of dorsocervical fat.

Trajectory of patients consulting the emergency department for high blood pressure values.

OBJECTIVES: Emergency department (ED) visits for high blood pressure are increasing in frequency. We aimed to map those patients' trajectory, from referral sources to the type of care received at the ED to anticipated actions for future high blood pressure concerns, and to better understand their reasons for consulting the ED for high blood pressure values. METHODS: Between 2018 and 2020, patients who presented to the Montreal Heart Institute's ED for elevated blood pressure were recruited in a prospective observational study including a post hoc structured telephone interview and medical chart review. Five possible referral sources were predetermined. We provided proportions and 95% confidence intervals. RESULTS: A total of 100 patients were recruited (female: 59%, mean age: 69 ± 12). A majority (93%, 95% CI 88-98%) possessed a home blood pressure device, among which 46% (95% CI 36-56%) remembered receiving advice for its use. The main referral sources for high blood pressure to the ED were self-reference (53%, 95% CI 43-63%), advice of a lay person (19%, 95% CI 11-27%) or a nurse (13%, 95% CI 6-20%). Mainly, patients reported being concerned by concomitant symptoms or experiencing acute medical consequences (44%, 95% CI 34-54%), having followed the recommendation of a third party (33%, 95% CI 24-42%), or having concerns about their medication (6%, 95% CI 1-11%). Two weeks following their ED visits, consulting ED remained the main choice for future concerns about high blood pressure for 27% of participants. When specifically asked if they would return to the ED for elevated blood pressure, 73% (95% CI 64-83%) said yes. CONCLUSIONS: Most patients who consulted the ED for elevated blood pressure values were self-referred. More can be done to promote blood pressure education, effective use of personal blood pressure devices, and recommendations for patients and health professionals when confronted with high blood pressure results.

RéSUMé: OBJECTIFS: Les visites aux services d'urgence pour hypertension artérielle (TA) sont de plus en plus fréquentes. Nous avons cherché à cartographier le parcours de ces patients, depuis les sources d'orientation jusqu'au type de soins reçus aux urgences, en passant par les mesures prévues en cas de problèmes futurs de tension artérielle élevée, et à mieux comprendre les raisons pour lesquelles ils consultent les urgences pour des valeurs de tension artérielle élevées. MéTHODES: Entre 2018 et 2020, les patients qui se sont présentés aux urgences de l'Institut de cardiologie de Montréal pour une TA élevée ont été recrutés dans le cadre d'une étude observationnelle prospective comprenant une entrevue téléphonique structurée post-hoc et un examen des dossiers médicaux. Cinq sources de référence possibles ont été prédéterminées. Nous avons fourni des proportions et des intervalles de confiance à 95 %. RéSULTATS: Au total, 100 patients ont été recrutés (femmes : 59 %, âge moyen : 69 ± 12). Une majorité (93%, IC à 95% 88-98%) possédait un tensiomètre à domicile, parmi lesquels 46% (IC à 95% 36-56%) se souvenaient avoir reçu des conseils pour son utilisation. Les principales sources d'orientation vers les urgences en cas de tension artérielle élevée étaient l'auto-référence (53 %, IC 95 % 43-63 %), le conseil d'un tiers non-professionnel de la santé (19 %, IC à 95 % 11-27 %) ou d'une infirmière (13 %, IC à 95 % 6-20 %). Principalement, les patients ont déclaré être préoccupés par des symptômes concomitants ou des conséquences médicales aiguës (44 %, IC à 95 %, 34-54 %), avoir suivi la recommandation d'un tiers (33 %, IC à 95 %, 24-42 %) ou avoir des préoccupations au sujet de leurs médicaments (6 %, IC à 95 %, 1-11 %). Deux semaines après leur visite au service d'urgence, la consultation du service d'urgence est restée le principal choix en cas de préoccupations futures concernant l'hypertension artérielle pour 27 % des participants. À la question spécifique de savoir s'ils retourneraient aux urgences pour une TA élevée, 73% (IC à 95% 64-83%) ont répondu oui. CONCLUSIONS: La plupart des patients qui ont consulté les urgences pour des valeurs élevées de la tension artérielle se sont adressés d'eux-mêmes. Il y a place à l'amélioration pour promouvoir l'éducation sur la TA, l'utilisation efficace des appareils de pression artérielle personnels et les recommandations aux patients et aux professionnels de la santé lorsqu'ils sont confrontés à des résultats élevés en matière de TA.

Characteristics and relationship between hyperphagia, anxiety, behavioral challenges and caregiver burden in Prader-Willi syndrome.

OBJECTIVES: Prader-Willi syndrome (PWS) is a rare genetic disorder characterized by maladaptive behaviors, amongst which hyperphagia is a life-long concern for individuals with PWS and their caregivers. The current study examined the contribution of hyperphagia and other factors to caregiver burden across lifespan, in 204 caregivers of individuals with PWS living in the US, using the Zarit Burden Interview (ZBI) and the hyperphagia questionnaire (HQ-CT). RESULTS: We found a strong relationship between ZBI and HQ-CT especially in individuals with PWS older than 4 y and showed that HQ-CT scores of individuals with PWS is positively correlated with ZBI scores of their caregivers. The weight status of individuals with PWS was not associated with HQ-CT and ZBI scores, except for obese individuals who had significantly higher HQ-CT scores when compared to normal weight PWS individuals. We looked at PWS symptoms and care-related issues that impacted individuals and caregivers the most. We found that care-related tasks had the biggest negative impact on caregivers of children aged 0-4 y, whereas anxiety, temper tantrums, and oppositional behaviors of older individuals with PWS had the biggest impact on their caregivers concomitant with their high caregiver burden. Finally, we assessed the variability of HQ-CT and ZBI over 6 months in a subgroup of 83 participants. Overall, neither measure differed between 6 months and baseline. Most individual's absolute HQ-CT score changes were between 0-2 units, whereas absolute ZBI score changes were between 0-6 points. Changes in the caregiver's or individual's life had little or no effect on HQ-CT and ZBI scores. CONCLUSIONS: This study demonstrates a relationship between hyperphagia and caregiver burden and sheds light on predominant symptoms in children and adolescents that likely underly PWS caregiver burden. The stability and relationship between HQ-CT and ZBI support ZBI as an additional outcome measure in PWS clinical trials.

Visceral fat reduction with tesamorelin is associated with improved liver enzymes in HIV.

OBJECTIVE: Tesamorelin reduces visceral adipose tissue (VAT) in HIV. We investigated whether reductions in VAT with tesamorelin are associated with changes in alanine aminotransferase (ALT) and aspartate aminotransferase (AST). DESIGN AND METHODS: We utilized data from two multicenter Phase III trials of tesamorelin among 806 HIV-infected patients with abdominal obesity. These studies showed that the majority of patients treated with tesamorelin are 'responders', defined a priori by the Food and Drug Administration as achieving at least 8% reduction in VAT. In the current analysis, we sought to examine the impact of VAT reduction on ALT and AST among patients participating in the Phase III trials with baseline elevated ALT or AST. Within this group, we compared changes in ALT and AST in VAT responders vs. nonresponders after 26 weeks of treatment, and then assessed the effects of drug discontinuation on these endpoints over a subsequent 26-week period. RESULTS: At baseline, VAT was positively associated with ALT (P = 0.01). In study participants assigned to tesamorelin with baseline ALT or AST more than 30 U/l, VAT responders experienced greater reductions in ALT (-8.9 ±â€Š22.6 vs. 1.4 ±â€Š34.7 U/l, P = 0.004) and AST (-3.8 ±â€Š12.9 vs. 0.4 ±â€Š22.4 U/l, P = 0.04) compared with nonresponders over 26 weeks. This improvement among VAT responders persisted over 52 weeks even in those switched to placebo despite a partial reaccumulation of VAT. CONCLUSION: A clinically significant VAT reduction with tesamorelin was associated with improved liver enzymes among HIV-infected patients with abdominal obesity and elevated baseline transaminases.

Is there an Upgrading to Malignancy at Surgery of Mucocele-Like Lesions Diagnosed on Percutaneous Breast Biopsy?

Management of pure mucocele-like lesion (MLL) diagnosed on percutaneous breast biopsy (PBB) is controversial. To assess surgical upgrade rate and clinical outcome of pure MLL obtained as sole diagnosis on PBB. Patients diagnosed with a MLL as the most advanced lesion on PBB from April 1997 to December 2010 were reviewed for radiologic presentation, biopsy technique, and pathologic and clinical outcomes. Of the 21,340 image-guided PBB performed during the study period, 50 women with 51 MLL (0.24%) were identified. Mean age was 53.1 ± 7.7 years. Radiologic findings were mostly microcalcifications (n = 47, 92.2%). Stereotactic PBB was performed for 49 lesions (96.1%). Surgery was performed shortly after biopsy in 35 women, with benign final pathology in 33, and upgrade to ductal carcinoma in situ (DCIS) in two patients (2/35, 5.7%). Mean follow-up was 4.2 ± 2.5 years (3.7 ± 2.1 years for surgical patients; 5.9 ± 2.9 years for follow-up only patients); three women were lost to follow-up (3/50). Three invasive cancers (3/47, 6.4%) were diagnosed 1.2, 1.2, and 2.8 years after biopsy: two in surgical patients, and one in a follow-up only patient. No cancer occurred at the same site as the original MLL. Pure MLL lesion of the breast is a rare entity and is mostly associated with a benign outcome. We observed an upgrade to DCIS slightly superior to 5%, but no invasive cancer. It is therefore unclear if these lesions should be excised or clinically and radiologically followed up when such lesions are found at PBB.

Canadian Association for Enterostomal Therapy evidence-based recommendations for conservative sharp wound debridement: an executive summary.

The Canadian Association for Enterostomal Therapy Conservative sharp wound debridement evidence-based recommendations are a result of the decision and commitment to advance clinical nursing practice to improve the provision of care to patients via development of an open source guide. The recommendations were developed by a volunteer group of ET nurses who work in clinical practice, policy development, consultation, and education in wound care. The document was developed over the course of 2 years (2009-2011); it is a distillation of existing literature, guidelines, and expert opinion. The development and dissemination of the recommendations were sponsored by the Canadian Association for Enterostomal Therapy. These recommendations should be considered in the context of the organization or care setting as well as available resources and supports. Resources and supports take the form of access to emergency care, physicians and allied health care professionals, education, administrative support, funding, supplies, equipment, and policy. The recommendations should also be applied with consideration of the evolving evidence that will further define practices in Conservative Sharp Wound Debridement. Refer to the supplemental digital content associated with this article at (supplemental digital content 1, http://links.lww.com/JWOCN/A16) for the complete document.

Impact of Tesamorelin, a Growth Hormone-Releasing Factor (GRF) Analogue, on the Pharmacokinetics of Simvastatin and Ritonavir in Healthy Volunteers.

The potential impact of tesamorelin on CYP3A activity was investigated by examining its effect on the pharmacokinetics of simvastatin and ritonavir. In two randomized, two-way crossover studies, subjects were administered 2 mg tesamorelin on Days 1-7 with 80 mg simvastatin or 100 mg ritonavir co-administered on Day 6 (Treatment A), and a single dose of simvastatin or ritonavir alone on Day 6 (Treatment B). Pharmacokinetic samples were collected on Day 6 to measure simvastatin, ritonavir and tesamorelin plasma concentrations. For simvastatin, A/B ratios of least squares geometric means and corresponding 90% confidence intervals (CIs) for AUC0-t , AUC0-inf and Cmax were contained within the usual no effect range of 80-125%. For ritonavir, ratios and 90% CIs for AUCs were within this acceptance range, but the lower CI for Cmax was 74.8%, suggesting a decreased rate of exposure. However, since the A/B ratios for AUCs and Cmax parameters were approximately 90%, these were minor decreases and no dose adjustment of ritonavir is required in the presence of tesamorelin. These studies showed that the impact of tesamorelin on CYP3A activity appears to be minimal, if any. Either medication may be co-administered with tesamorelin in patients without changing their original dosing regimen.

Reduction in visceral adiposity is associated with an improved metabolic profile in HIV-infected patients receiving tesamorelin.

BACKGROUND: Tesamorelin, a growth hormone-releasing hormone analogue, decreases visceral adipose tissue (VAT) by 15%-20% over 6-12 months in individuals with human immunodeficiency virus (HIV)-associated abdominal adiposity, but it is unknown whether VAT reduction is directly associated with endocrine and metabolic changes. METHODS: In 2 phase III, randomized, double-blind studies, men and women with HIV-associated abdominal fat accumulation were randomly assigned (ratio, 2:1) to receive tesamorelin or placebo for 26 weeks. At week 26, patients initially receiving tesamorelin were randomly assigned to continue receiving tesamorelin or to receive placebo for an additional 26 weeks. In per-protocol analysis of 402 subjects initially randomly assigned to receive tesamorelin, those with ≥8% reduction in VAT were defined a priori as responders per the statistical analysis plan. Post hoc analyses were performed to assess differences between responders and nonresponders. RESULTS: Compared with tesamorelin nonresponders, responders experienced greater mean (±SD) reduction in triglyceride levels (26 weeks: -0.6 ± 1.7 mmol/L vs -0.1 ± 1.2 mmol/L [P = .005]; 52 weeks: -0.8 ± 1.8 mmol/L vs 0.0 ± 1.1 mmol/L [P = .003]) and attenuated changes in fasting glucose levels (26 weeks: 1 ± 16 mg/dL vs 5 ± 14 mg/dL [P = .01]; 52 weeks: -1 ± 14 mg/dL vs 8 ± 17 mg/dL [P < .001]), hemoglobin A1c levels (26 weeks: 0.1 ± 0.3% vs 0.3 ± 0.4% [P < .001]; 52 weeks: 0.0 ± 0.3% vs 0.2 ± 0.5% [P = .003]), and other parameters of glucose homeostasis. Similar patterns were seen for adiponectin levels, with significant improvement in responders vs nonresponders. Changes in lipid levels and glucose homeostasis were significantly associated with percentage change in VAT. CONCLUSIONS: In contrast to nonresponders, HIV-infected patients receiving tesamorelin with ≥8% reduction in VAT have significantly improved triglyceride levels, adiponectin levels, and preservation of glucose homeostasis over 52 weeks of treatment. CLINICALTRIALS.GOV REGISTRATION: NCT00123253, NCT00435136, NCT00608023.

Bradykinin protects against brain microvascular endothelial cell death induced by pathophysiological stimuli.

The morphological and functional integrity of the microcirculation is compromised in many cardiovascular diseases such as hypertension, diabetes, stroke, and sepsis. Angiotensin converting enzyme inhibitors (ACEi), which are known to favor bradykinin (BK) bioactivity by reducing its metabolism, may have a positive impact on preventing the microvascular structural rarefaction that occurs in these diseases. Our study was designed to test the hypothesis that BK, via B2 receptors (B2R), protects the viability of the microvascular endothelium exposed to the necrotic and apoptotic cell death inducers H(2)O(2) and LPS independently of hemodynamics. Expression (RT-PCR and radioligand binding) and functional (calcium mobilization with fura-2AM, and p42/p44MAPK and Akt phosphorylation assays) experiments revealed the presence of functional B2R in pig cerebral microvascular endothelial cells (pCMVEC). In vitro results showed that the cytocidal effects of H(2)O(2) and LPS on pCMVEC were significantly decreased by a BK pretreatment (MTT and crystal violet tests, annexin-V staining/FACS analysis), which was countered by the B2R antagonist HOE 140. BK treatment coincided with enhanced expression of the cytoprotective proteins COX-2, Bcl-2, and (Cu/Zn)SOD. Ex vivo assays on rat brain explants showed that BK impeded (by approximately 40%) H(2)O(2)-induced microvascular degeneration (lectin-FITC staining). The present study proposes a novel role for BK in microvascular endothelial protection, which may be pertinent to the complex mechanism of action of ACEi explaining their long-term beneficial effects in maintaining vascular integrity.

Novel kinin B1 receptor agonists with improved pharmacological profiles.

There is some evidence to suggest that inducible kinin B1 receptors (B1R) may play beneficial and protecting roles in cardiovascular-related pathologies such as hypertension, diabetes, and ischemic organ diseases. Peptide B1R agonists bearing optimized pharmacological features (high potency, selectivity and stability toward proteolysis) hold promise as valuable therapeutic agents in the treatment of these diseases. In the present study, we used solid-phase methodology to synthesize a series of novel peptide analogues based on the sequence of Sar[dPhe(8)]desArg(9)-bradykinin, a relatively stable peptide agonist with moderate affinity for the human B1R. We evaluated the pharmacological properties of these peptides using (1) in vitro competitive binding experiments on recombinant human B1R and B2R (for index of selectivity determination) in transiently transfected human embryonic kidney 293 cells (HEK-293T cells), (2) ex vivo vasomotor assays on isolated human umbilical veins expressing endogenous human B1R, and (3) in vivo blood pressure tests using anesthetized lipopolysaccharide-immunostimulated rabbits. Key chemical modifications at the N-terminus, the positions 3 and 5 on Sar[dPhe(8)]desArg(9)-bradykinin led to potent analogues. For example, peptides 18 (SarLys[Hyp(3),Cha(5), dPhe(8)]desArg(9)-bradykinin) and 20 (SarLys[Hyp(3),Igl(5), dPhe(8)]desArg(9)-bradykinin) outperformed the parental molecule in terms of affinity, functional potency and duration of action in vitro and in vivo. These selective agonists should be valuable in future animal and human studies to investigate the potential benefits of B1R activation.

Comparative bioequivalence study between a novel matrix transdermal delivery system of fentanyl and a commercially available reservoir formulation.

AIM: To determine the pharmacokinetics, safety and performance of a novel matrix formulation of fentanyl. METHODS: Transdermal fentanyl was administered as the novel matrix and the Durogesic reservoir formulations (24 subjects, 100 microg h(-1)) in a randomized, fully replicate, four-way crossover study. Serum concentrations of fentanyl were assayed by LC/MS/MS. Pharmacokinetic parameters of fentanyl and performance (adherence and skin irritability) were evaluated. RESULTS: Test/reference ratio (90% confidence intervals) for AUC(0-t), AUC(inf) and C(max) were 105.5% (99.4, 112.0), 105.3% (99.3, 111.6) and 111.4% (100.4, 123.6), respectively. Adherence and skin irritability results of the two formulations were similar. CONCLUSION: The two formulations are expected to result in similar efficacy for the management of severe pain.

Hypotensive effects of hemopressin and bradykinin in rabbits, rats and mice. A comparative study.

Hemopressin is a novel vasoactive nonapeptide derived from hemoglobin's alpha-chain as recently reported by Rioli et al. [Rioli V, Gozzo FC, Heimann AS, Linardi A, Krieger JE, Shida CS, et al. Novel natural peptide substrates for endopeptidase 24.15, neurolysin, and angiotensin-converting enzyme. J Biol Chem 2003;278(10):8547-55]. In anesthetized male Wistar rats, this peptide exhibited hypotensive actions similar to those of bradykinin (BK) when administered intravenously (i.v.), and was found to be metabolized both in vitro and in vivo by several peptidases, including the angiotensin-converting enzyme (ACE). In this study, these findings were expanded upon by examining: (i) the degradation kinetics following incubation with ACE purified from rabbit lung and (ii) the blood pressure lowering effects of HP and BK injected i.v. or intra-arterially (i.a.) in male rabbits, rats, and mice. Our findings demonstrate that, in vitro, HP and BK are both degraded by ACE, but at different velocity rates. Furthermore, both HP and BK induced transient hypotension in all animals tested, although the responses to HP relative to the administration sites were significantly lower (by 10-100-fold) on an equimolar basis compared to those of BK. In rabbits, the decrease of blood pressure induced by HP (10-100 nmol/kg) did not differ whether it was administered i.v. or i.a., suggesting an absence of pulmonary/cardiac inactivation in contrast to BK (0.1-1 nmol/kg). The in vivo effect of HP was significantly potentiated in rabbits immunostimulated with bacterial lipopolysaccharide (LPS), but was unaffected by both the B2 receptor antagonist HOE 140 (0.1 micromol/kg) and captopril (100 microg/kg), contrary to BK. Therefore, HP acts as a weak hypotensive mediator, which does not activate kinin B2 receptors, but uses a functional site and/or signaling paths appearing to be up-regulated by LPS.

Contractile responses of aortae from WKY and SHR to vasoconstrictors.

Aortae taken from spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) rats aged 4, 8 and 16 weeks were prepared as rings and used to measure the effects of five vasoconstrictors. The endothelium was removed in order to measure selectively the contractile responses induced by potassium chloride (KCl), phenylephrine (PHE), angiotensin-II (Ang II), endothelin-1 (ET-1) and human urotensin-II (U-II). These responses were assumed to derive from the activation of specific receptors (namely alpha1, AT1, ETA and UT-II) or from depolarization of the smooth muscle fibers by KCl. Specific antagonists prazosin, losartan, BQ-123 and [Orn8]-UII were used at various concentrations for a pharmacological characterization of these latter receptor systems. The primary purpose of the study was to explore mechanisms or factors that may intervene in the development and maintenance of high blood pressure in SHR. Results indicate that isolated aortae of SHR and WKY contain contractile sites (receptors) whose pharmacological profiles (pEC50 for agonists, pA2 for antagonists) are very similar to those of other biological systems and should be considered as typical for the alpha1, AT1, ETA and UT-II receptor types. Aortae taken from SHR 4 (non hypertensive), 8 and 16 weeks old (hypertensive) responded to the vasoconstrictors with reduced maximal contractions compared to those of age-matched WKY. These unexpected reduced responses of aortae, observed with the five vasoconstrictors, may be attributed to a non specific lesions. Maximal contraction of aortae from SHR increased from 4 to 16 weeks for KCI, PHE and U-II, decreased for Ang II, and remained stable for ET-1. There was also an age-dependent increase of maximal contraction induced by U-II in WKY. It is suggested that aortae from SHR undergo early remodelling that leads to reduced contractility in vitro and possibly to vessel rigidity in vivo. The factors involved in this process appear to be of genetic origin since they are present before hypertension: they may contribute to modify aortic compliance and perhaps vascular resistance in hypertensive animals and thus being the cause and not the consequence of high blood pressure.

Trauma-induced occlusion of the left anterior descending artery following a snowmobile accident in a man without prior coronary artery disease.

Blunt chest trauma can cause several forms of heart injuries, of which myocardial infarction (MI) is recognized as a rare complication. An unusual case of occlusion of the left anterior descending artery following a snowmobile accident, with two episodes of sustained ventricular tachycardia, is presented here. Management of the occluded artery included angioplasty and stenting, less than 5 h following the trauma. The resultant decreased ejection fraction following the event emphasizes the importance of rapid intervention in the setting of acute MI following nonpenetrating trauma.