The modified obstetric metabolic equivalent (MET): finding a MET that fits in pregnancy.

The Compendium of Physical Activities (CPA) provides the energy expenditure (EE) for hundreds of daily activities reported in metabolic equivalents (MET). It remains to be determined if the metabolic changes of pregnancy alter the use of the CPA MET (METCPA) in this population. The energy cost of rest, activities of daily living (ADL; typing, folding laundry and sweeping) and treadmill walking [2.0, 2.5, 3.0 mph (0% incline), 3.0 mph (3% incline)] were compared with the METCPA from the 2000 and 2011 CPA in 30 pregnant women (10-14 weeks gestation) using indirect calorimetry (IC). The METCPA for each activity was compared against two measured IC values: METabsolute (3.5 ml O2/kg/min) and METratio (EEactivity/EErest). Means for both comparisons were tested by one-sample t-test. Measured MET correlated with the 2011 METCPA: METabsolute v. METCPA R 2 = 0.906, P < 0.0001; METratio v. METCPA R 2 = 0.861, P < 0.0001. Differences between measured MET values and the 2011 METCPA ranged from 16% underestimation to 48% overestimation. Using the absolute definition, the METCPA significantly overestimated the ADL (P < 0.0005); yet, no significant differences were found between walking at 0% grade and METCPA. Conversely, only folding laundry was significantly different with the ratio definition, whereas walking at a level grade was significantly underestimated (P < 0.0001). Similar observations were found using the 2000 CPA. The use of the METCPA to estimate EE in pregnant women can result in significant over- or underestimation, depending on the activity and the definition of the MET that is used.

Feasibility of a walking workstation to increase daily walking.

OBJECTIVE: The number of calories expended in the workplace has declined significantly in the past 75 years. A walking workstation that allows workers to walk while they work has the potential to increase caloric expenditure. We evaluated whether employees can and will use walking workstations while performing their jobs. METHODS AND PROCEDURES: We studied nurses, clinical assistants, secretaries and appointment secretaries using the StepWatch Activity Monitor System (which accurately measures steps taken at slow speeds) while performing their job functions in their usual fashion and while using the walking workstation. RESULTS: Subjects increased the number of steps taken during the workday by 2000 steps per day (p<0.05). This was equivalent to an increase in caloric expenditure of 100 kcal/day. Subjects reported that they enjoyed using the workstation, that it could be used in the actual work arena and that, if available, they would use it. DISCUSSION: Walking workstations have the potential for promoting physical activity and facilitating weight loss. Several subjects in this study expended more than 200 extra calories daily using such a system. Further trials are indicated.

A prospective randomized trial of Duraflo II heparin-coated circuits in cardiac reoperations.

BACKGROUND: Heparin-coated circuits in cardiopulmonary bypass have been shown to decrease the systemic inflammatory responses associated with cardiopulmonary bypass. Previous clinical studies on low-risk patients who had coronary artery bypass grafting (CABG) and received full-dose systemic heparin did not have clearly improved clinical outcomes. We hypothesized that the beneficial effects of heparin-coated circuits might be seen in patients who had cardiac reoperations. METHODS: Three hundred fifty patients who had reoperation with CABG only (58%), or with valve operations (42%) were randomly assigned to receive either a heparin-coated (Duraflo II; study group) or uncoated (control group) circuit. Clinical outcomes were compared and the variables were analyzed using the following three groups: entire populations of study group and control group, subgroup of patients who had CABG reoperation only, and a subgroup who had valve reoperation or combined valve and CABG reoperation. RESULTS: Preoperative variables were the same in both groups. No difference in clinical outcomes could be demonstrated except that the percentage of patients with major bleeding episodes was significantly lower in the study group (1.2% versus 5.4%, p = 0.035). In the subgroup analysis of patients who had valve reoperations, lower blood transfusion requirements in the intensive care unit (p = 0.013) were found in the study group. When the subgroup of patients who had CABG reoperations was analyzed separately, there was a trend toward less reoperation for bleeding in the study group (0% versus 4.0%, p = 0.058). CONCLUSIONS: We conclude that the use of heparin-coated circuits was safe and imparted protection from reoperations for bleeding and major bleeding episodes. Material-independent blood activation (eg, blood-air interface and cardiotomy suction) blunted the total effect of the heparin-coated surface.

Extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock.

BACKGROUND: Extracorporeal membrane oxygenation circuits have recently been introduced for extracorporeal life support (ECLS) in adult patients in cardiogenic shock and have been shown to provide excellent oxygenation and hemodynamic support. Heparin coating of the extracorporeal circuit provides a more biocompatible surface, which has been shown to minimize early surface-induced complement activation and platelet dysfunction and hence may improve patient survival. This report reviews our experience with extracorporeal membrane oxygenation to treat postcardiotomy cardiogenic shock using minimal to no systemic heparinization in 23 patients. METHODS: During the 22-month period September 1992 through July 1994, 23 patients in cardiogenic shock were placed on venoarterial ECLS using a heparin-bonded circuit. These patients' charts were retrospectively reviewed. A logistic regression analysis of the variables collected was performed to identify clear-cut predictors of ability to be weaned from ECLS. RESULTS: Average patient age was 47.3 +/- 16.4 years (range, 5 to 72 years). There were 17 male patients. Average time on ECLS was 58.4 +/- 35.1 hours (range, 0.5 to 144 hours). Statistical analysis revealed that patients unable to be weaned from ECLS were more likely to have a critically dilated left ventricle on echocardiography and were female. Ten patients (43.5%) died while on ECLS. Four patients were transferred to an implantable left ventricular assist device, and 3 underwent successful transplantation. The 9 other patients were successfully weaned from ECLS, and 4 were discharged home from the hospital. Overall, 7 patients (30.4%) who were placed on ECLS were successfully discharged home. CONCLUSIONS: Extracorporeal life support using an extracorporeal membrane oxygenation system provides excellent cardiac support with similar hospital survival rates as centrifugal mechanical support. Extracorporeal life support has complications unique to itself, but with time, these are likely to be overcome. Women and patients with persistent left ventricular dilatation are less likely to be weaned.

Complications of extracorporeal life support systems using heparin-bound surfaces. The risk of intracardiac clot formation.

Extracorporeal life support with heparin-coated extracorporeal membrane oxygenation circuits are being used with increased frequency in patients who have cardiogenic shock. We report our experience in 30 patients with cardiogenic shock, looking specifically at the complications associated with this form of life support. Thirty patients with a mean age of 46.5 +/- 16.6 years received extracorporeal life support for a mean of 62.8 +/- 41.1 hours (range 0.5 to 159 hours). Twenty-three patients had postcardiotomy cardiogenic shock, five had acute myocardial infarction, and one each had acute cardiac deterioration after a balloon coronary angioplasty and another after pulmonary artery balloon angioplasty. Peripheral (femoral vein to femoral artery) cannulation was used in 24 patients. Limb ischemia developed in 21 patients (70%), renal failure in 17 patients (57%), oxygenator failure requiring change in 13 patients (43%), bleeding requiring reexploration in 12 (40%), and infection in 9 patients (30%). Transesophageal echocardiography revealed intracardiac thrombus formation in 6 patients (20%) and clot was visualized grossly in the pump head in 2 patients (6%) necessitating pump-head change. Nine patients (30%) were discharged home. We conclude that the use of heparin-coated extracorporeal life support without systemic heparinization, especially after protamine has been used to reverse systemic heparinization in patients having postcardiotomy cardiogenic shock, may be dangerous. Extracorporeal life support has introduced new complications unique to itself specifically limb ischemia, oxygenator failure, and pump-head thrombus.

Catalase and sulfur in the rice rhizosphere: An ultrastructural histochemical demonstration of a symbiotic relationship.

An ultrastructural study has been made of a symbiotic association between a sulfur bacterium and the roots of the rice plant (Oryza saliva L.). This association is proposed to have useful economic consequences in ameliorating hydrogen sulfide toxicity and associated Akiochi or Straighthead disease in lowland rice cultivation. The presence of catalase (E.C. 1.11.1.6) in rice roots and in some rhizosphere bacteria has been demonstrated in ultrathin sections of field-grown rice using a catalasespecific medium. Catalase was detected in capsules surrounding the catalase-negative S-bacteria. These capsules were of a novel fibrillar structure. Two sizes of inclusion bodies were present in these large bacteria. The disappearance of the smaller inclusions during carbon disulfide treatment suggests that they are the sulfur granules. The name "thiosome" is proposed for these membrane-bound structures.

Polysaccharides in soil fabrics.

Treatment of ultrathin sections of natural soil fabrics with heavy metal stains, specific for carbohydrates, showed that polysaccharides are widely distributed in soils. In addition to being associated with living cells and dead remains of plants and microbes, carbohydrates also coat clay platelets and occur in crevices of submicron size within mineral aggregates. The determination of the precise location of polysaccharides in soils explains in part why some carbohydrates are resistant to microbial degradation and why small quantities of microbial polysaccharides are able to stabilize clay aggregates.

Sterols of Delphinium ajacis; production and metabolic relationships in whole plants and callus tissue.

Sterols from whole nonsterile Delphinium ajacis plants and from sterile tissue cultures (callus) were identified and determined quantitatively. The major sterols in the whole plant tissues were sitosterol, campesterol and stigmasterol, whereas those in the callus tissue were stigmastanol, 24-ethylidenelophenol and Delta (7)-stigmastanol. Of the 21 compounds identified in callus tissue, 5 were not present in the whole plant, most notably Delta (7)-stigmastanol. For both sources of tissue, the sterol predominating in one was a minor component in the other (whole plant/tissue cultures: sitosterol 57%/5%; stigmastanol 2%/35%). On a tissue dry-weight basis, the amount of sterols isolated from callus tissue culture was ten to twenty times that obtained from the whole plant. Qualitatively the sterols from both sources fit into a metabolic scheme which proceeds from cycloartenol through 4,4-dimethylsterols and 4-methylsterols to sterols. A proposed metabolic pathway shows the differences in accumulation of sterols in the two types of tissue. The increase in sterol production in cultured cells, especially when favored by growth conditions, has promise for industrial application and in organic synthesis.

A putative role for cell-cell epithelial contacts in lactose secretion.

Rates of synthesis and secretory release and the maximal requisite intracellular transit time (Tsec) for lactose were measured in vitro for three preparations of lactating guinea pig mammary tissue: tissue slices, mammary epithelial cell (MEC) acini, and mono-dispersed MEC. The Tsec values for tissue slice and acini preparations were similar, lactose required approximately 16 min to pass from its site of synthesis (Golgi) to the extracellular medium. Dispersal of mammary tissue into single cells by collagenase disruption of all cell-cell junctional complexes increased the Tsec value to approximately 25 min but did not alter kinetics of lactose synthesis and secretory release. These data suggest a possible involvement of cell-cell junctional contacts in intracellular transport of lactose.

Changes in mouse mammary epithelial cell size during mammary gland development.

The average volume and size distribution of mouse mammary epithelial cells (MMEC) at different stages of functional activity of the mammary gland have been estimated. During early pregnancy, the mean MMEC volume begins to enlarge, resulting in a 21-fold cell volume increase by late lactation (Day 18). Progressive increases in mean MMEC volume during late pregnancy and throughout lactation result from the appearance and progressive hypertrophy of secretory alveolar cells. Involution of the mammary tissue brings about a precipitous decrease both in the average MMED volume and in the distribution of cell sizes established during the later phases of lactation. The progressive hypertrophy of cells particularly throughout the lactational period appear to correlate with previously reported changes in the metabolic activities of the mammary gland.