Oxygen uptake and cardiac output during progressive and constant load work in patients after acute myocardial infarction

PURPOSE: Simultaneously measured oxygen uptake (VO2) and Doppler echocardiography could verify if an alteration in the VO2 response to progressive and constant load work is due to reduced cardiac output. METHODS: The study group consisted of nine patients after acute myocardial infarction (MI), five age-matched healthy subjects (HE), and five young well-trained subjects (WT). Each subject performed a progressive exercise test and two bouts of constant load work at power outputs equated to 10% below (W1) and 10% above (W2) their ventilatory thresholds. VO2 and cardiac output were measured continuously and simultaneously during the tests. RESULTS: VO2 was significantly reduced for the MI group during the initial stages of the progressive exercise test (P < .02) and remained lower throughout the entire test. During the first 60 seconds of constant load work (W2), VO2 was lower for MI (P < .05). At steady state exercise during W2, cardiac output was significantly less for MI (P < .05). VO2 for the MI group was more reliant on cardiac output during lower power outputs and differences in the arterial and venous O2 content (a-VO2 difference) during greater power outputs. CONCLUSIONS: Cardiac rehabilitation programs must be aware of this delayed VO2 and cardiac output response when setting training workloads or selecting the magnitude of the workload increments during progressive exercise tests.     

The impact of clinical pharmacists on psychiatric patients

BACKGROUND: Studies of population biology are scarce in Mediterranean striped dolphins (Stenella coeruleoalba) mostly because of the lack of samples. Until now, studies of physical maturity, growth, and development of the flipper bones were not available for this species in the Mediterranean. METHODS: The osteological features and metric characters of the pectoral limbs of Mediterranean striped dolphins were analyzed with radiological techniques. Measurements were made directly on the radiographic films. RESULTS AND CONCLUSIONS: We found five carpal bones arranged in a proximal row of three and a distal row of two, although one or two additional osseous elements were occasionally observed. The phalangeal formula (excluding metacarpals) was established as 1-2:8-9-10:6-5-7:3-2:1-2. In metacarpals, epiphyseal ossification centers matured at the same time at both ends. As a general rule, the ossification of the epiphyses in the flipper bones showed a decreasing gradient in the proximodistal direction, confirming the pattern previously described in other species. Phalangeal epiphyses were not useful as indicators of skeletal maturity, and grading epiphyseal maturation of the distal radius and ulna is proposed as the more straight-forward and precise method for assessing bone maturation. In females, maturity of the flipper was achieved between 5 and 6 years of age and 160-175 cm of body length, whereas this maturation occurred between 8 and 9 years of age and 170-181 cm in length in males. Prediction of gender through examination of flipper structure was not feasible.     

A study of the performance and comparability of the sampling response to cotton dust of work area and personal sampling techniques

In order to compare and contrast the sampling response to cotton dust of two forms of dust sampling 85 work areas were identified over a 2-year period for investigation in eight Lancashire spinning mills. Three hundred and five work area dust samples were undertaken and 252 personal dust samples were performed. Operatives who spent a minimum of 80% of their working shift in the area in which work area sampling was also performed were selected for personal sampling. Work area dust exposures have recently shown an upward trend, with highest concentrations occurring in the ring spinning room (median 1.15 mg m-3, range 0.82-2.06). Personal dust samples showed a reduction in dust exposures as cotton processing progressed, from a high in the opening room (median value of 6.24 mg m-3, range 1.0-41.5) to a minimum of 1.02 mg m-3 (range 0.30-0.93) in the winding room. The ratio of measured personal sampling dust exposure to work area sampling exposure was used to compare the relative performance of the two techniques. This ratio was highest in the early processes. There was a 7.8-fold difference in measurement between the two techniques in the opening processes, falling to 4.9 in carding and 4.2 in the other card-room processes. However in ring spinning the ratio was only 1.4, suggesting a degree of comparability in the methods at this stage of processing. The value rose to 2.5 for the last stage (winding). Respiratory disease is known to occur predominantly in the early stages of processing (opening and carding) where high dust concentrations are found using the personal technique. These data support the use of personal sampling for setting exposure limits to cotton dust in preference to the current recommended method using work area sampling techniques, which may significantly underestimate dust exposure in the high risk work areas and is outdated.     

Coronary sinus pacing prevents induction of atrial fibrillation

BACKGROUND: Atrial fibrillation (AF) is due to reentry, and its incidence has been shown to decrease after dual-site atrial or biatrial pacing. We investigated whether a simpler pacing approach via the distal coronary sinus (CSd) could eliminate AF inducibility by high right atrial (HRA) extrastimuli (APDs). We based our hypothesis on our previous observation that AF inducibility by HRA APDs was associated with conduction delays to the posterior triangle of Koch, whereas AF was never induced with CSd APDs, which were associated with minimal intra-atrial conduction delays. METHODS AND RESULTS: Programmed electrical stimulation was performed from the high right atrium and CSd, and bipolar recordings were obtained from the high right atrium, His bundle, posterior triangle of Koch, and coronary sinus. In 13 patients (age, 44+/-18 years), AF was reproducibly induced with a critically timed HRA APD (220+/-22 ms) delivered during HRA pacing. AF was not induced in any of the patients when HRA APDs were delivered during CSd pacing at the same critical coupling intervals. Coronary sinus APDs delivered during HRA pacing also were not associated with AF induction. The APD coupling interval measured at the posterior triangle of Koch during CSd pacing was significantly prolonged compared with the one measured during HRA pacing and AF induction (381+/-58 versus 263+/-37 ms; P<.0001). CONCLUSIONS: We propose that CSd pacing suppresses the propensity of HRA APDs to induce AF by limiting their prematurity at the posterior triangle of Koch and not allowing local conduction delay and local reentry to occur.     

The effect of halothane on the recirculatory pharmacokinetics of physiologic markers

BACKGROUND: The cardiovascular effects of halothane are well recognized, but little is known of how this affects drug distribution. The effect of halothane anesthesia on physiologic factors that affect drug disposition from the moment of injection was investigated. METHODS: The dispositions of markers of intravascular space and blood flow (indocyanine green), extracellular space and free water diffusion (inulin), and total body water and tissue perfusion (antipyrine) were determined in four purpose-bred coonhounds. The dogs were studied while awake and while anesthetized with 1%, 1.5%, and 2% halothane in a randomized order determined by a repeated measures Latin square experimental design. Marker dispositions were described by recirculatory pharmacokinetic models based on frequent early and less frequent later arterial blood samples. These models characterize the role of cardiac output and its distribution on drug disposition. RESULTS: Halothane caused a significant and dose-dependent decrease in cardiac output. The disposition of antipyrine was most profoundly affected by halothane anesthesia, which increased both nondistributive intercompartmental clearance and volume while decreasing fast and slow tissue clearances and elimination clearance in a halothane dose-dependent manner. CONCLUSIONS: Halothane-induced changes in blood flow to the compartments of the antipyrine recirculatory model were not proportional to changes in cardiac output. Halothane anesthesia significantly increased (to more than double) the area under the drug concentration versus time curve due to an increase in the apparent peripheral blood flow not involved in drug distribution, despite a dose-dependent cardiac output decrease. Recirculatory pharmacokinetic models include the best aspects of traditional compartmental and physiologic pharmacokinetic models while offering advantages over both.     

Sequences of the primate epsilon-globin gene: implications for systematics of the marmosets and other New World primates

Sequences of the epsilon-globin gene were determined for five species of marmosets, along with approximately 2 kb of 5' flanking sequence. An analysis of these data, compared with those of other primates strongly supports the classification of Callithrix jacchus and C. geoffroyi into the jacchus group, and C. argentata and C. mauesi into the argentata group. The pygmy marmoset, formerly identified as Cebuella pygmaea joined strongly to the argentata group, indicating that without the pygmy marmoset the genus Callithrix would be paraphyletic. Our data support recent studies which indicate that C. pygmaea should be included in the genus Callithrix. Relationships among other primates were as indicated by previous studies of epsilon-globin sequences. Divergence times were estimated according to a local molecular clock. These calculations indicated the divergence of C. mauesi and C. argentata to be approximately 1.6-1.9 Myr (million years ago), and the most recent common ancestor of the marmosets to be between 4.5 and 4.7 Myr. The latter estimate corresponds well to the date of 4.6 Myr calculated from an independent data set.     

Perinatal asphyxia and heart problems

New bisantrene analogues were synthesized, bearing one or two 4,5-dihydro-1H-imidazol-2-yl hydrazone side chains at positions 1,4 or 9 of the anthracene ring system. A 10-azabioisostere was also prepared. The position of substituents in structurally isomeric drugs modulates topoisomerase II poisoning and specificity, along with cytotoxicity.