Physical aptitudes to exertion in children with Down's syndrome

ABSTRACT. The individual with Down's syndrome is characterized by apathy towards physical exercise. Ten untrained subjects with Down's syndrome and a control group have been tested at rest and after exercise on a bicycle ergometer. In subjects with Down's syndrome, the authors have observed: (a) a lower orthostatic index at rest; (b) a lower indirect maximal oxygen consumption; (c) a shorter performance time and a lower maximal workload; (d) a higher urinary catecholamines excretion; (e) a blood pressure which did not rise regularly with the workload increment. It is concluded that, in subjects with Down's syndrome, the low level of physical fitness is not only explained by lack of motivation but also by physiological impairments.     

Comparing Cause-Specific Infant Mortality in a West German State and the United States of America

ABSTRACT. The infant mortality rate in North Rhine Westphalia (NRW), the most populous West German state, has continuously been around 10 % higher than the German national average in the post-war period. Using white singleton data from the US 1980 National Infant Mortality Surveillance project (NIMS) and similar 1980/1981 data from NRW we compared infant mortality by birthweight and cause to describe the distribution of excess mortality in NRW. The US infant mortality rate was 8.7 deaths per 1000 live births, compared with 13.1/1000 for NRW (rate difference: 4.3/1000). Of the 4.3/1000 overall rate difference, 1.9/1000 was attributable to neonatal deaths, 2.4/1000 to postneonatal deaths. A major proportion, 2.0/1000, of the overall rate difference of 4.3/1000 was attributable to normal birthweight deaths postneonatally. 0.85/1000 of this 2.0/1000 rate difference was attributable to SIDS, 0.44/1000 to external causes and 0.42/1000 to infections.     

The Feasibility of Fully Automated Pacemaker Advise in Treating Atrial Tachyarrhythmias

Background: Modern pacemakers continuously store significant cardiac‐related events. Interpreting these data and reprogramming the pacemaker can be time‐consuming and demands expert knowledge. A software‐based expert system, the therapy advisor (TA), was developed, which analyzes stored data and provides reprogramming recommendations. This study addresses whether pacemaker experts consider the messages that are automatically generated appropriate in the management of atrial tachyarrhythmias/atrial fibrillation (AT/AF). Methods: This observational, international, multicenter study follows 150 patients with suspected or documented atrial arrhythmias who received a dual‐chamber pacemaker (model Vitatron T‐70, Medtronic Inc., Minneapolis, MN, USA) incorporating the TA. The TA summarizes technical and clinical data stored in the pacemaker into key messages and may suggest programming changes. Twenty‐five cardiologists examined their patients per normal practice during two follow‐up visits. They reported the therapy changes they deemed necessary without initially reviewing the TA messages. Next, they rated their satisfaction with and the clinical relevance of the TA messages and recorded the final therapy changes. Results: The TA generated (mostly AT/AF‐related) main observations in 49% and programming advice in 33% of the patients. The experts rated 95% of the TA messages as satisfactory and deemed therapy changes necessary in roughly half the patients. Pacemaker changes in AT/AF therapy or general settings were prompted primarily by the diagnostic information stored in the device. Medication changes were mostly led by the symptoms reported by the patient. Conclusion: This study demonstrates that experienced cardiologists agree with 95% of the observations and programming suggestions that the TA automatically generates. (PACE 2010; 605–614)     

Mapping Guided Laser Catheter Ablation of the Atrioventricular Conduction in Dogs

Safety and efficacy of mapping guided laser catheter ablation of the AV junction was tested in a canine model. A total of 43 laser pulses (continuous wave, Nd:YAG, 1,064 nm, 30 W, irradiated spot diameter 2.0–2.5 mm) were delivered in 15 dogs (2–5 per dog) via a novel laser catheter system. Pulses were selectively aimed at: (1) the AV node: (2) the His bundle; and (3) the bundle branches. Laser pulses of 9.7 ± 1.1 seconds (n = 31) produced reversible conduction disturbances in the targeted segment of the AV conduction system, while pulses of 28.6 ± 7.9 seconds (n = 9) resulted in chronic block. The dogs survived the procedure without complications. Follow-up was 6.5–10.5 months. Histopathologically, lesions showed clear-cut oval-shaped areas of fibrosis of 0.5–18.0 mm in diameter and 0.5–3.5 mm (transmural) in depth, depending on the irradiation time. Pervenous mapping guided laser catheter irradiation of the AV junction can produce AV block consistently and selectively in the targeted segment of the right ventricular conduction system in dogs. The method is safe and can be performed in a controllable manner by using the catheter system presented.     

Spontaneous chemical degradation of substance P in the solid phase and in solution

The instability of the undecapeptide substance P (SP), a neuropeptide implicated in several physiological processes, was occasionally observed when the peptide was stored in the solid state or in solution. The aim of the present study was to identify the decomposition products of SP stored as lyophilized peptide or in aqueous neutral solution. The main pathway of the decomposition of SP acetate consists of the subsequent release of N-terminal dipeptides via their diketopiperazines. cyclo(Arg-Pro) and cyclo(Lyys-Pro). In contrast to the decomposition of the acetate of SP, the hydrochloride and trifluoroacetate salts were found to be considerably more stable. Under the studied conditions the release of N-terminal dipeptides dominates over other possible routes of spontaneous modifications, such as S-oxidation and deamidation.     

Nephropathy in Type II diabetes

Summary: The incidence and prevalence of end-stage renal failure due to renal involvement in patients with type II diabetes has increased in the Western world and in Asia. Interesting differences of prevalence of this disease are found between nations. the reasons for the increase in the frequency of nephropathy in type II diabetes include: (i) an increasing prevalence of type II diabetes; (ii) ageing of the population; and (iii) improved survival of patients with type II diabetes. Today patients frequently live long enough to develop diabetic nephropathy. In contrast with previous opinion, no major differences in renal involvement is found between type I and type II diabetes. This applies to renal haemodynamics as well as renal histology, although non-specific changes, presumably of an ischaemic nature are more frequently found in patients with type II diabetes. the renal risk appears to be similar in type II diabetes (i.e. cumulative prevalence of proteinuria and rate of progression to renal failure).     

Age-dependent differences in the effect of phenprocoumon on the vitamin K1-epoxide cycle in rats†

The anticoagulant activity and the pharmacokinetics of phenprocoumon as well as the effect of phenprocoumon on the vitamin K₁-epoxide cycle in younger (12 weeks) and older (36 weeks) male inbred Lewis rats has been examined in a study of the mechanism responsible for the increase in the responsiveness to oral anticoagulant drugs (OAD's) with increasing age. After a single i.v.-dose of phenprocoumon (0?355 mg kg^?1 the anticoagulant effect obtained was greater in older than in younger rats. There were no differences between younger and older rats in the rate of elimination, volume of distribution and in the free fraction and free concentration values of phenprocoumon in plasma and liver. After i.v.- injection of 64·3 μg kg^?1 [³ H]vitamin K₁ and different doses of phenprocoumon (0·02 to 3 mg kg^?1) the [³ H]vitamin K₁ concentration in the liver decreased and the [³ H] vitamin K₁-2, 3-epoxide concentration increased dependent on the dose and the liver concentration of phenprocoumon. These changes were more pronounced in the older than in the younger rats. Concentration-response curves gave similar EC50-values for both age-groups but a 1·6-fold higher maximal response (expressed as vitamin K₁-epoxide/vitamin K₁ ratios) in the older rats. Since OAD's exert their anticoagulant effect most probably by inhibiting an enzyme (vitamin K₁-epoxide reductase) which regenerates vitamin K₁ from the epoxide metabolite and since the vitamin K₁-epoxide/vitamin K₁ ratios in the liver may reflect the degree of inhibition of the epoxide reductase by OAD's, our results may indicate that the inhibitory effect of phenprocoumon on this enzyme is more pronounced in older than in younger rats. This could explain the age-dependent differences in the anticoagulant activity.