Effects of load and type of physical training on resting and postexercise cardiac autonomic control

The aim of the study was to investigate the influence of training load and exercise mode on heart rate variability and heart rate recovery (HRR) in healthy individuals. The subjects were divided into three groups: sedentary (SED), resistance trained (RT) and aerobically trained (RT). Resting and postmaximal exercise RR intervals were recorded on supine and seated position, respectively. The HRV indices calculated in the resting position were RMSSD and LF and HF power densities. The following HRR indices were calculated throughout the 5‐minute postmaximal recovery period: semi‐logarithmic regression analysis of the first 30 s (T30); absolute difference between the peak and 60 s HR (HRR_60s); and mono‐exponential time constant of HRR (HRRτ). The RMSSD on subsequent 30‐s segments (RMSSD_30s) on recovery period was also calculated. Both RT and AT groups presented faster HRR than SED (P<0·05). The aerobic trained group was the only group that presented vagal reactivation, when analysing the RMSSD_30s. There were no correlations between the Baecke sport score and the HRV vagal‐related indices. However, it was significantly correlated with HRR. It was concluded that that the training load positively influences the HRR, but has no effect on the HRV at rest and that the type of exercise, showed a marked influence on HRV recovery.     

Peritoneal Resting with Heparinized Lavage Reverses Peritoneal Type I Membrane Failure. A Comparative Study of the Resting Effects on Normal Membranes

♦ Background: Ultrafiltration failure (UFF) is a serious complication of long-term peritoneal dialysis (PD). Peritoneal rest (PR) has been demonstrated as a valid treatment to reverse the functional changes that occur in UFF. The effects of PR on a normally functioning human peritoneum are unknown but are expected to be neutral. Our hypothesis was that PR positively modifies peritoneal function in patients with UFF, in contrast to the absence of effects when PR is applied under normal conditions.♦ Patients and Methods: We studied 84 PR periods, comparing 35 patients with UFF and 49 controls (resting for abdominal surgery with temporary discontinuation of PD). We analyzed peritoneal transport pre-PR and post-PR by calculating the mass transfer coefficients of creatinine (Cr-MTAC), the dialysate/plasma creatinine ratio (D/P Cr) and the ultrafiltration (UF).♦ Results: Baseline data was similar for the 2 groups, although the UFF group had a longer median time in PD (39 [18 - 60] vs 10 [5 - 23] months; p = 0.00001). Peritoneal rest induced a decrease in D/P Cr, Cr-MTAC and an increase in UF capacity in the UFF group (p = 0.0001, p = 0.004 and p = 0.001, respectively), without causing changes in the control group. Peritoneal rest in patients with more than 6 months of UFF was not able to reduce peritoneal solute transport or improve UF capacity. Response to PR did not differ among UFF patients with or without a previous history of peritonitis. Peritoneal rest enabled patients with UFF to continue on PD for a median time of 23 months (range, 13 - 46 months).♦ Conclusions: Peritoneal rest induces functional changes in patients with UFF but not in those with no functional abnormalities. This demonstrates that PR works only when abnormal but reversible functional conditions are present. However, the effect is highly dependent on how early PR is applied.     

Impact of a structured intensive follow-up program on the control of hypertension in coronary patients--a randomized trial.

INTRODUCTION: Hypertension is an important risk factor for cardiovascular events. Although several anti-hypertensive agents have shown to be effective in the treatment of hypertension, adequate blood pressure control is not frequent in most populations. The aim of this study was to evaluate the effect of a structured intensive follow-up program (SIFUP) on the control of blood pressure in coronary patients. PATIENTS AND METHODS: we performed a prospective, randomized study including 237 patients admitted to the Cardiology Department for acute coronary syndrome. Patients were randomly assigned to a SIFUP (n=129) or to the general cardiology outpatient department (COD) (n=108). An experienced doctor performed a blind assessment of blood pressure in 157 randomised patients, 9 to 18 months after discharge. In statistical analysis, the chi-square test was used to compare proportions and the Student's t test to compare means. RESULTS: Both groups were predominantly male and mean age was similar. The proportion of patients with known hypertension randomised to the SIFUP and the COD did not differ. At the 9 to 18-month assessment there was no statistical significant difference in the proportion of patients with blood pressure under target values (57.5% in SIFUP and 48.5% in COD, p=NS). However, in hypertensive patients, the proportion of controlled patients was significantly higher in the SIFUP than in the COD (44.8% vs. 24.2%, p=0.05) and systolic and mean blood pressure were significantly lower in the SIFUP (respectively 139.0 vs. 148.8 mmHg, p=0.04 and 98.7 vs. 103.9 mmHg, p=0.03); diastolic blood pressure was also lower in SIFUP (78.5 vs. 81.5 mmHg, p=NS). CONCLUSIONS: The SIFUP has shown to be effective in lowering blood pressure in hypertensive coronary patients. The proportion of patients with controlled blood pressure was consistently higher in the SIFUP.     

Acute coronary syndromes in young women.

INTRODUCTION: Acute coronary syndromes (ACS) in young women are relatively unusual. This subgroup of patients presents a premature risk of death and disability, with significant social repercussions. OBJECTIVE/METHODOLOGY: This retrospective study was undertaken to define risk factors, symptoms and signs at presentation, electrocardiographic and angiographic characteristics, treatment and complications, in pre-menopausal women younger than fifty years old, admitted to the Coronary Care Unit between 1991 and 2002. RESULTS: We evaluated 33 patients (mean age 43.0 years). The most frequent risk factors were hypertension (48.5%) and smoking (45.5%). Typical chest pain (78.7%) and tachycardia (34.1%) were the most prevalent symptom and sign respectively. A history of previous angina was present in 18% of the patients. The most common presenting electrocardiographic finding was ST segment elevation (45.5%). Critical coronary lesions were present in 78.7%, mainly in the left anterior descending (LAD) (54.5%). Single-vessel disease was more frequent than multi-vessel disease (57.6% vs. 18.2%). Coronary arteries were angiographically normal in 9.1%. Left ventricular dysfunction assessed by echocardiography was present in 63.6%. Recurrent angina was the most common complication (24.2%). No fatal cases were recorded. Acute reperfusion therapy was indicated in fifteen patients: direct angioplasty in six, thrombolysis in six and none in three. Elective revascularization was performed in seventeen patients (angioplasty in ten and coronary artery bypass graft in seven). Secondary prevention included platelet antiaggregants in 100%, beta-blockers in 81.5%, angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers in 42.2%, and statins in 42.2%. Diagnosis at discharge was Q-wave myocardial infarction (anterior--36.3% and inferior--15.2%), non-Q wave myocardial infarction (27.2%), and unstable angina (21.2%). CONCLUSIONS: This study shows that atherosclerosis was the principal etiopathogenic factor in young women with ACS. Hypertension and smoking were the commonest risk factors. Critical LAD stenosis, Q-wave myocardial infarction (mostly anterior) and left ventricular dysfunction were common.     

Report of two cases of spontaneous direct carotid-cavernous fistula

Summary Spontaneous fistulas presenting as direct communication between the carotid siphon and cavernous sinus are very rare. They occurred in two patients where a dissection as possible cause is discussed. The diagnostic and therapeutic aspects are described.     

Visual-vestibular interaction studied with stroboscopically illuminated visual patterns

Summary Horizontal DC-electrooculograms were recorded in subjects rotating on a horizontal turntable sinusoidally at 0.1 Hz and 35 to 40° amplitude. The subjects either fixated a stroboscopically illuminated vertically striped pattern (1.15 to 3.45° period) rotating with the turntable or initiated Sigma-OKN before the rotation began and tried to maintain Sigma-OKN during rotation. In a third paradigm, interaction of vestibulo-ocular reflex (VOR) and Phi OKN was studied. (1) VOR-suppression by fixation was complete within the limits of EOG-recording precision (±1° · s^-1) for flash frequencies f_s>10 flashes · s^-1. VOR-suppression decreased monotonically with f_s between 10 and 1 flashes · s^-1. (2) A similar dependency on f_s was found for VOR-suppression during Sigmaor Phi-OKN. Above 10 flashes · s^-1 VOR-suppression remained incomplete; below 5 flashes · s^-1 VOR-suppression was stronger with the Sigma-OKN paradigm than during fixation and depended on spatial frequency of the pattern. (3) During sinewave rotation of the subject the perceived speed V_p of Sigma-movement correlated to the movement of gaze in space and not to the movement of the eye in head. (4) In a control experiment with normal optokinetic stimulation, OKN-suppression by fixating a small flashing target was found to depend on f_s in a similar way as VOR-suppression in the experiments described above.     

Camptothecin analogs with enhanced activity against human breast cancer cells. I. Correlation of potency with lipophilicity and persistence in the cleavage complex

The effect of 7-alkyl substitutions on growth inhibition in seven Camptothecin (CPT) ring systems with various groups at the ten position was evaluated in three human breast cancer cell lines that model (1) hormone-sensitive (MCF-7/wt), (2) hormone insensitive (MDA-MB-231), or (3) alkylator-resistant (MCF-7/4-hc) forms of disease. To assess the impact of persistence of cleavage complexes on antiproliferative activity, a post-exposure recovery period in drug-free medium was incorporated into the growth inhibition assay. This modification produced on average a twofold reduction in the growth inhibition endpoint (the IC50), suggesting a greater apoptotic response. The results further revealed a three log range in potency from a mean IC₅₀ of 2 nM (7-butyl-10,11-methylenedioxy-CPT) to 2.5 μM (7-bromomethyl-10-hydryoxy-CPT). Increasing 7-alkyl chain length in six of the ten-substituted CPTs enhanced potency, which was directly correlated with persistence of topoisomerase I-induced DNA cleavage complexes in 10-hydroxy, 10-methoxy, and 10,11-methylenedioxy substituted CPTs. Modeling of the binding mode of 7-butyl-10-amino-CPT revealed a direct hydrogen bond contact for the 10-amino to the side chain of Glu-356 of Core Subdomain I of top1 in addition to known contacts found for other camptothecins. More important, residues 350–356 and 425–431 of Core Subdomain I may provide induced fit stabilization to the lipophilic alkyl moiety at the seven position.     

Induction of oxidative stress in brain of glutaryl-CoA dehydrogenase deficient mice by acute lysine administration

In the present work we evaluated a variety of indicators of oxidative stress in distinct brain regions (striatum, cerebral cortex and hippocampus), the liver, and heart of 30-day-old glutaryl-CoA dehydrogenase deficient (Gcdh(-/-)) mice. The parameters evaluated included thiobarbituric acid-reactive substances (TBA-RS), 2-7-dihydrodichlorofluorescein (DCFH) oxidation, sulfhydryl content, and reduced glutathione (GSH) concentrations. We also measured the activities of the antioxidant enzymes glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT), superoxide dismutase (SOD) and glucose-6-phosphate dehydrogenase (G6PD). Under basal conditions glutaric (GA) and 3-OH-glutaric (3OHGA) acids were elevated in all tissues of the Gcdh(-/-) mice, but were essentially absent in WT animals. In contrast there were no differences between WT and Gcdh(-/-) mice in any of the indicators or oxidative stress under basal conditions. Following a single intra-peritoneal (IP) injection of lysine (Lys) there was a moderate increase of brain GA concentration in Gcdh(-/-) mice, but no change in WT. Lys injection had no effect on brain 3OHGA in either WT or Gcdh(-/-) mice. The levels of GA and 3OHGA were approximately 40% higher in striatum compared to cerebral cortex in Lys-treated mice. In the striatum, Lys administration provoked a marked increase of lipid peroxidation, DCFH oxidation, SOD and GR activities, as well as significant reductions of GSH levels and GPx activity, with no alteration of sulfhydryl content, CAT and G6PD activities. There was also evidence of increased lipid peroxidation and SOD activity in the cerebral cortex, along with a decrease of GSH levels, but to a lesser extent than in the striatum. In the hippocampus only mild increases of SOD activity and DCFH oxidation were observed. In contrast, Lys injection had no effect on any of the parameters of oxidative stress in the liver or heart of Gcdh(-/-) or WT animals. These results indicate that in Gcdh(-/-) mice cerebral tissue, particularly the striatum, is at greater risk for oxidative stress than peripheral tissues following Lys administration.