Greater Percent Change Research Articles

Thermodynamics of the Dimensional Changes in the Wheat Kernel during Cooking for Bulgur Production

Thermodynamics and physical properties of the dimensional changes in the wheat kernel during cooking was carried out for bulgur production at 87, 92 and 97°C for 140min. There were determined changes of the length ( x-dimension), two widths ( y- and z-dimensions), weight, volume and density of the wheat kernel. The length of the wheat kernel during cooking decreased, although crease-side width ( y-dimension) and secondary width ( z-dimension) significantly increased ( p 0.05) at each cooking temperature between 6.95-68.05% and 9.95-69.00%, respectively. The volume of the kernel during cooking also significantly ( p 0.05) increased (27.35-185.20%), and had a greater percentage change value than the weight (19.25-160.70%) due to swelling of the wheat kernel. Therefore, density decreased negatively. Activation energy, enthalpy, entropy and Gibbs free energy were used to describe the changes of physical attributes of the wheat kernel during cooking. Rate constant values for the length and density of the wheat kernel were negative in contrast to positive rate constant values of the widths, weight and volume of the wheat kernel. The influence of cooking temperature on the physical properties of the wheat kernel revealed that the rate of change in the secondary width ( z-dimension), weight and density of the wheat kernel were more sensitive to temperature due to their greater activation energies, 5.95 107, 5.26 107 and 6.11 107 J, respectively. In contrast, the y-dimension of width of the wheat kernel required a lower amount of energy due to crease side. All of the changes in physical properties agreed with the positive values of Gibbs free energy.

Deflection and deceleration of hydrogen Rydberg molecules in inhomogeneous electric fields.

Hydrogen molecules are excited in a molecular beam to Rydberg states around n=17-18 and are exposed to the inhomogeneous electric field of an electric dipole. The large dipole moment produced in the selected Stark eigenstates leads to strong forces on the H2 molecules in the inhomogeneous electric field. The trajectories of the molecules are monitored using ion-imaging and time of flight measurements. With the dipole rods mounted parallel to the beam direction, the high-field-seeking and low-field-seeking Stark states are deflected towards and away from the dipole, respectively. The magnitude of the deflection is measured as a function of the parabolic quantum number k and of the duration of the applied field. It is also shown that a large deflection is observed when populating the (17d2)1 state at zero field and switching the dipole field on after a delay. With the dipole mounted perpendicular to the beam direction, the molecules are either accelerated or decelerated as they move towards the dipole. The Rydberg states are found to survive for over 100 micros after the dipole field is switched off before being ionized at the detector and the time of flight is measured. A greater percentage change in kinetic energy is achieved by initial seeding of the beam in helium or neon followed by inhomogeneous field deceleration/acceleration. Molecular dynamics trajectory simulations are presented highlighting the extent to which the trajectories can be predicted based on the known Stark map. The spectroscopy of the populated states is discussed in detail and it is established that the N+=2, J=1, MJ=0 states populated here have a special stability with respect to decay by predissociation.

Desmosterol: a biomarker for the efficient development of 20,25-diazacholesterol as a contraceptive for pest wildlife.

20,25-Diazacholesterol is being evaluated as a contraceptive for the nonlethal control of avian and mammalian wildlife pests. The identification of an analyte in blood which was highly correlated with absorbed dose and efficacy is valuable for determining effective formulations and dosing variables. Such an analyte or biomarker is also valuable for determining the percentage of pest populations that consume an effective dose of the active ingredient in the field. HPLC analyses of blood collected from dosed animals failed to detect 20,25-diazacholesterol but indicated that levels of free cholesterol and related compounds were affected by 20,25-diazacholesterol absorption. The greatest percent change in chromatographic peak area associated with 20,25-diazacholesterol administration was observed for desmosterol, a cholesterol precursor. 20,25-Diazacholesterol appeared to block the conversion of desmosterol to cholesterol, resulting in an elevated concentration of the precursor. The elevation of blood desmosterol levels is being used as an indicator of 20,25-diazacholesterol absorption and to facilitate the development of a 20,25-diazacholesterol-based contraceptive for pest wildlife.

Efficacy of IV Theophylline in Children with Severe Status Asthmaticus

Purpose of the Study. To determine if the addition of intravenous (IV) theophylline to an aggressive treatment regimen of inhaled and IV beta-agonists, inhaled ipratroprium and IV methylprednisolone would enhance the recovery of children with severe status asthmaticus admitted to the pediatric intensive care unit (PICU).Study Population. Forty-seven children with a diagnosis of status asthmaticus who were admitted to the Cardinal Glennon Children’s Hospital in St Louis PICU for ≤2 hours. All subjects were in severe distress with a modified Wood-Downes clinical asthma score (CAS) of ≥5. Subjects’ age range was 13 months to 17 years.Methods. Subjects were enrolled who fulfilled the above criteria. In brief, the CAS includes measures of oxygenation, breath sounds, accessory muscle use, expiratory wheezing, and cerebral function. Admission to the PICU was determined by inadequate response to repeated albuterol treatments and the ED and critical care staff. Subjects were randomly assigned to receive in addition to their regular aggressive treatment (denoted above in purpose of study) either IV aminophylline 7 mg/kg loading dose followed by age adjusted rates of 0.5–0.65 mg/kg/hr or no additional treatment (controls). Theophylline levels were kept between 12 to 17 μg/mL. The CAS evaluations were performed by investigators blinded to the treatment and were performed twice daily by 1 of 4 investigators. The PICU attending and resident team were all aware of the treatment assignment and made all medical decisions related to the subjects. CAS was suspended in the event of intubation and resumed on extubation. Nursing staff was queried regarding side effects of the subjects.Results. There was no significant difference between the theophylline and control groups with respect to age, sex, race, home medications, past use of hospital resources, origin (ED or ward), ED treatment, or time of admission. The baseline CAS scores were not different. Six subjects required mechanical ventilation (3 in each group), although the 3 control subjects were intubated after treatment and the 3 in the theophylline group before treatment was begun. Subjects receiving IV theophylline had a significant decrease in time to reach CAS ≤3 and a greater percentage change in respiratory rate than control subjects during the first 12 hours in the PICU. Theophylline did not significantly influence the time to meet PICU discharge criteria among patients not receiving mechanical ventilation, but in those requiring intubation, the PICU stay was reduced. There was no significant difference in adverse effects between the 2 groups, except and increase in complaints of emesis in the theophylline group and increase in tremor in the control group.Conclusions. Contrary to the National Heart Lung and Blood Institute guidelines for treatment of status asthmaticus in children, this study suggests that critically ill children with severe status asthmaticus may benefit from the addition of IV theophylline to β-agonist, anticholinergic, and corticosteroid therapies. Additional studies may examine the administration of theophylline to select patients in the ED unresponsive to conventional therapy or in patients known to be high risk for respiratory failure.Reviewer’s Comments. This is the first prospective randomized trial of IV theophylline limited to children admitted to the PICU. Other studies in hospitalized (noncritical care) asthmatic children failed to show a benefit with the addition of theophylline to conventional treatment. It is possible that the benefit of the addition of theophylline is dependent on the severity of their illness. Adult studies have shown the improvement in spirometry with the addition of a methylxanthine is related to the degree of airway narrowing. The addition of theophylline may serve to reduce the incidence of respiratory failure and mechanical ventilation in children with severe status asthmaticus. The authors note that not blinding the medical team to the treatment may have influenced the results to some degree, but for safety reasons, they did not feel that was warranted. The authors referred to this as a “controlled” study, but there was no reference to a placebo (ex: saline). It would be interesting to repeat this study with a placebo control and with some of the newer critical care treatments such as heliox.

Estrogen replacement therapy moderates the sleep disruption associated with nocturnal blood sampling.

To determine whether chronic oral estrogen replacement therapy (ERT) (1) improves the sleep of older, non-symptomatic postmenopausal women; and (2) reduces the sleep disruption associated with a stressor (frequent remote nocturnal blood-sampling through an intravenous catheter). Descriptive, cross-sectional, secondary analysis of a larger study. The General Clinical Research Center at the University of Washington Medical Center. Women aged 57-80 (mean age = 70) at least 5 years past menopause were recruited from the community. Hot flashes and significant sleep difficulties were exclusion criteria. The ERT group (n=37) consisted of women on chronic oral ERT for > or = 2 years. The NERT group (n=56) consisted of women not using estrogen (NERT) for > or = 2 years. N/A. Following an adaptation night, polysomnographic measures were collected for 2 consecutive nights. A blood sample was collected every 20 minutes for the last 24 hours (including Night 2), through an intravenous catheter. The only group difference in sleep on the baseline (non-catheter) night was that NERT women had a shorter sleep latency. Sleep on the catheter night was characterized by increased wakefulness, longer sleep latency, and decreased REM sleep for both groups relative to the baseline. However, the impact of nocturnal blood sampling was much greater for NERT than for ERT women: they experienced significantly greater percent changes in more sleep-wake variables, particularly slow-wave sleep (SWS). In this cross-sectional study, the use of chronic oral ERT was associated with little effect on the sleep of older postmenopausal women not experiencing hot flashes, except in the presence of a challenge to sleep. ERT ameliorated the disruptive effect of nocturnal blood sampling on both objectively assessed and subjectively assessed sleep.

Microbial and nutrient activity in soils from three different subtropical forest habitats in Belize, Central America before and during the transition from dry to wet season

Significant variations were found in soil texture, levels of organic carbon, microbial biomass carbon, nitrate, and nitrification rates in the upper 20 cm of soil from three distinct Uplands forest, Cohune Palm forest, and Bajo forest habitats within the subtropical rainforest of Northwestern Belize. The Cohune Palm forest soils had the most organic carbon, microbial biomass carbon, nitrate, and highest nitrification rates, while the soils from the Bajo forests had the lowest levels of these parameters. The heterogeneity in the soil composition is even more significant given that the three habitats studied are part of the same ‘forest’ and are within 2 km of each other. The first rains at the beginning of the wet season had a rapid and significant effect on various components in the soil. A rapid increase in the microbial biomass carbon, organic carbon, and nitrification rates and a decrease in nitrate occurred in the soil from all three habitats within hours after what locals anecdotally consider the start of the wet season. The greatest percent change in all factors following the rains occurred within the soil from the Bajo forests, while the smallest percent change occurred within soil from the Uplands forest. There were also significant correlations found between soil moisture levels and organic carbon, microbial biomass carbon, and nitrification rates. The variations in the measured parameters were also associated with the amount of clay in the soil. It appears, then, that the amounts of moisture and clay are most critical soil composition factors which when combined with microbial biomass carbon, organic carbon, and nitrification rates may be good predictors of soil quality in these forests.

Effect of Submucosal Diathermy to the Inferior Turbinates on Unilateral and Total Nasal Airflow in Patients with Rhinitis

The efficacy of the controversial treatment of submucosal diathermy to the inferior turbinates (SMDIT) was evaluated objectively. Twenty-seven patients with chronic rhinitis were investigated by hourly posterior rhinomanometry to assess changes in total and minimum (Fmin) and maximum (Fmax) unilateral nasal airflow over 5 h, before and 2-3 months after standardized SMDIT treatment. Nasal airflow was recorded at a sample pressure of 75 Pa and the results are reported as medians with interquartile range. Whilst SMDIT caused a significant 51% increase (p<0.0001) in total nasal airflow from 246 cm3/s (131) to 371 cm3/s (133) the changes in unilateral airflow provided further evidence which strongly supported the benefits of this operation. Unilateral Fmin significantly increased by 136% (p<0.0001) from 69 cm3/s (82) to 163 cm3/s (74) and Fmax significantly increased by 23% (p<0.0001) from 171 cm3/s (74) to 211 cm3/s (59). The effect of surgery was to ?splint? to the turbinate in a state of relative vasoconstriction. Our findings therefore provide functional evidence of submucosal fibrosis following SMDIT. The greater percentage change in unilateral Fmin suggests that this parameter is a more sensitive index of the effect of nasal surgery than total nasal airflow measurements. The importance of considering the nose as two separate airways in the evaluation of nasal treatments is emphasized.

Response of Fibrinolytic Proteins and Endothelin 1 to Venous Occlusion in Patients on Chronic Hemodialysis

The main purpose of the present study was to determine whether any abnormalities in the response of fibrinolytic activity to venous occlusion could be observed in patients undergoing chronic hemodialysis (HD patients). A 10-min venous occlusion test was performed in 13 HD patients and in 9 healthy subjects. The arm opposite to the arteriovenous fistula was occluded in HD patients. The following factors were measured: tissue plasminogen activator (t-PA), plasminogen activator inhibitor 1 (PAI-1), plasmin-alpha2-plasmin inhibitor complex (PIC), stabilized fibrin degradation product (D-dimer), and von Willebrand factor antigen determined by enzyme immunoassay, and endothelin 1 by radioimmunoassay with two antibodies. Preocclusion levels of PIC, D-dimer, von Willebrand factor, and endothelin 1 were significantly higher and those of t-PA significantly lower in HD patients than in controls. During the occlusion, there was a positive correlation between the percent changes in t-PA and von Willebrand factor and between those in von Willebrand factor and PIC. There was no correlation between percent and absolute changes during the occlusion in endothelin 1 and those in t-PA, PAI-1, PIC, D-dimer, or von Willebrand factor. There was no significant difference between HD patients and controls as to the percent changes in hematocrit, t-PA, PIC, D-dimer and von Willebrand factor. HD patients demonstrated a significantly greater percent change in PAI-1 than controls. The mechanism by which endothelin 1 is released in response to the occlusion appears to differ from that for t-PA, PAI-1, and von Willebrand factor. PAI-1 may be readily released in response to stimuli to blood vessels in HD patients.

Heparin Causes the Accumulation of Heparan Sulfate in Cultures of Arterial Smooth Muscle Cells

Heparin infusion in an experimental animal model of arterial injury causes a significant increase in the proteoglycan (PG) component of the extracellular matrix in the injured arteries (Snow, A.D., Bolender, R.P., Wight, T.N., and Clowes, A.W. (1990)Am. J. Pathol.137, 313–330). The mechanisms responsible for this heparin-induced increase in arterial PGs are not understood. To address this question, we have examined the effect of heparin on PG synthesis and accumulation by aortic smooth muscle cells in culture. Heparin causes a dose-dependent increase in the accumulation of PGs while the greatest percentage change among the different types of PGs is a doubling of the amount of heparan sulfate (HS) accumulated in the cell layer. There is also a selective enrichment of HS in the trypsin-resistant component of the cell layer indicating a specific modification in intracellular PGs. This change is due to the accumulation of large HS glycosaminoglycans (GAGs) which elute atKav≃ 0.3 on Sepharose CL-6B (Mr≃ 50,000) under dissociative conditions and which are absent from the controls. These GAGs are located inside the cell as is indicated by their retention after heparitinase or trypsin treatment of the cell layer. Furthermore, the increased accumulation of labeled HS in steady-state heparin-treated cells above controls does not appear for several hours after the addition of [35S]sulfate, indicating that HS accumulation is due to decreased degradation of the HS and not new synthesis. This possibility is further supported by the fact that degradation of the intracellular large HS in trypsinized cells is delayed for 2 h by incubation with heparin. These results suggest that heparin may reduce the intracellular degradation of HS through competitive inhibition of endogenous heparitinase.

連結固定が歯周組織の粘弾性特性に及ぼす影響

The purpose of the present study was to determine whether splinting of healthy teeth affected the mechanical mobility of each tooth. Upper first and second premolars, upper second premolar and first molar, or lower premolar and IMZ implants with titanium element were splinted with the device, without any changes of occlusal tooth contacts, which could be removed by the operator over about 2-month period. Horizontal mechanical mobility of individual teeth and implants were measured periodically.The results were as follows:1. The coefficient of variation in the mechanical mobility of splinted teeth for periods of experimental were significantly greater than those in non-splinted control teeth (p<0.01).2. For a few days after the start of splinting the effect of splinting on mechanical mobility of each tooth splinted was great significant.3. When a difference between the two initial mobility of teeth was large, the difference tended to become smaller after splinting. And furthermore, there was a greater percentage change in mobility of teeth that initially had smaller mobility than was the case for teeth that initially had greater mobility.4. The mobility of teeth did not decrease significantly after splinting with implants.

Evaluation of two new gadolinium chelates as contrast agents for MRI

Two new gadolinium chelates were investigated for potential use as tissue-specific contrast agents for magnetic resonance imaging. In vitro measurements of stability constants, octanol/water partition coefficients and relaxation times in solutions of water and human serum albumin (HSA) were performed with each new chelate and compared with gadolinium-diethylenetriamine pentaacetic acid, Gd(DTPA). Biodistribution studies and magnetic resonance imaging in rats were used to evaluate the new chelates in vivo. The stability constants (log K) of gadolinium- N,N″-bis(3-hydroxy-6-methyl-2-pyridylmethyl)diethylenetriamine- N,N′,N″-triacetic acid, Gd(DTTA-HP), and gadolinium-1,7-13-triaza-4,10-16-trioxacyclooctadecane- N,N′,N″-triacetic acid, Gd(TTCT), were determined to be 23.65 and 18.07, respectively. These can be compared to a literature value of 22.46 for Gd(DTPA). Octanol/water partition coefficients for both complexes showed they were more lipophilic than Gd(DTPA). Gd(DTTA-HP) exhibited a smaller relaxivity in water but a larger relaxivity in 4% HSA than Gd(DTPA). Gd(TTCT) exhibited a lower relaxivity than Gd(DTPA) in both water and 4% HSA. Both complexes showed similar biodistributions to Gd(DTPA) no carrier-added concentrations. Gd(DTTA-HP) had a greater percent change in signal intensity than Gd(DTPA) on T 1-weighted spin-echo images in the heart, liver, and kidney. Percent change in signal intensity for Gd(TTCT) was lower than Gd(DTPA) in heart, liver, and kidney.

Effect of wood ash application on soil pH and soil test nutrient levels

The use of wood residue as a fuel source for pulp and paper industries has led to the production of wood ash as by-product. Land spreading is a potentially sound method for the disposal of wood ash, which is an alternative soil liming agent. This study was conducted to determine the effect of wood ash amendment on soil pH and soil test nutrient levels as measured by a pH 3, 1 M NH 4OAc extractant. Wood ash and soil mixtures were incubated in the laboratory and then tested to determine soil pH and plant-available nutrient levels. The calcium carbonate equivalence of the ashes used ranged from 26 to 59%, indicating that the acid-neutralizing power of wood ash varies from source to source. The percentage of plant nutrients released from wood ash to soil varied with the particular nutrient. The average nutrient release percentages were: phosphorus (P), 5.7%; potassium (K), 40%; magnesium (Mg), 48%; calcium (Ca), 74%; sodium (Na), 16%. Wood ash application altered the equivalent fraction of K, Mg and Ca in soils. In general, the equivalent fraction of K and Mg decreased, while the equivalent fraction of Ca increased. The soils which had the least initial extractable Ca had the greatest percentage change in K, Mg and Ca equivalent fraction. Wood ash is an acceptable alternative liming agent which also provides modest amounts of P and K to soils.

Magnetic Resonance Imaging of Bone Marrow in Sickle Cell Disease: Clinical, Hematologic, and Pathologic Correlations

A longitudinal, prospective, controlled evaluation of magnetic resonance images (MRI) of long bones in sickle cell patients was undertaken simultaneously with assessment of clinical status and hematologic parameters, including dense erythrocytes. MRI of bone marrow in sickle cell patients during steady states appeared patchy and were markedly different from those in matched controls (P approximately 0). Patients with severe patchiness were older than those with mild or moderate patchiness (P less than .03). Sixty-nine MRI were performed during 28 painful episodes occurring in 14 subjects with sickle cell disease (SCD). Increased signals on intermediate and T2-weighted images were detected in 35.7% of painful episodes. These abnormalities were distinct and not observed to occur spontaneously during the steady-state examinations (P approximately 0). Bone marrow infarcts were confirmed by biopsy in two instances and autopsy in one instance. Dense red cells decreased by 40.81% of baseline during pain crises (P = .00005), more remarkably in those who had pain in the lower extremities (P = .0145). Patients with change in MRI during pain crises had a greater percentage change in the dense cells than those without the change in MRI (69.7% v 31.3%, P = .0120).

Magnetic resonance imaging of bone marrow in sickle cell disease: clinical, hematologic, and pathologic correlations

A longitudinal, prospective, controlled evaluation of magnetic resonance images (MRI) of long bones in sickle cell patients was undertaken simultaneously with assessment of clinical status and hematologic parameters, including dense erythrocytes. MRI of bone marrow in sickle cell patients during steady states appeared patchy and were markedly different from those in matched controls (P approximately 0). Patients with severe patchiness were older than those with mild or moderate patchiness (P less than .03). Sixty-nine MRI were performed during 28 painful episodes occurring in 14 subjects with sickle cell disease (SCD). Increased signals on intermediate and T2-weighted images were detected in 35.7% of painful episodes. These abnormalities were distinct and not observed to occur spontaneously during the steady- state examinations (P approximately 0). Bone marrow infarcts were confirmed by biopsy in two instances and autopsy in one instance. Dense red cells decreased by 40.81% of baseline during pain crises (P = .00005), more remarkably in those who had pain in the lower extremities (P = .0145). Patients with change in MRI during pain crises had a greater percentage change in the dense cells than those without the change in MRI (69.7% v 31.3%, P = .0120).

Phosphofructokinase control in muscle: nature and reversal of pH-dependent ATP inhibition.

The kinetic and regulatory properties of rabbit muscle phosphofructokinase (PFK:EC 2.7.1.11) have been reexamined in an attempt to clarify how the enzyme could achieve significant catalytic rates over the physiological pH range (down to 6.4). At 5.0 mM ATP, the apparent Km for fructose 6-phosphate (fructose 6-P) increases by at least 50-fold as the pH is decreased from 7.67 to 6.8 in 50 mM N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid-KOH buffer at 25 degrees C (7.50 to 6.63 at 37 degrees C). This effect can be nearly completely abolished in the presence of 10 microM fructose 2,6-bisphosphate (fructose 2,6-P2), with the greatest percentage change seen at low pH. In this case, the rabbit enzyme behaves as if the ATP concentration was low (1.0 mM) at any given pH. Conversely, at high ATP levels and a low pH of 6.8 at 25 degrees C, PFK behaves in the presence of fructose 2,6-P2 as if the pH has been increased to approximately 7.15 or a 0.35 pH unit shift at any given fructose 6-P concentration. At physiological concentration of fructose 6-P (0.1 mM), the positive effectors glucose 1,6-bisphosphate (glucose 1,6-P2) and either AMP, inorganic phosphate, or NH4+ were found to be, respectively, 60 and 40% as effective as fructose 2,6-P2 in reversing this pH-dependent ATP inhibition over the physiological pH range. In combination, however, glucose 1,6-P2 plus AMP were as effective as fructose 2,6-P2.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute increases in blood pressure cause arousal from sleep in lambs

We did experiments to determine whether or not acute increases in blood pressure would cause arousal from sleep. Nine lambs were studied 3–4 days after a balloon-tipped catheter was inserted via the femoral artery into the descending aorta and electrodes for the following recordings were implanted: electrocorticogram, electro-oculogram, electrocardiogram and diaphragm electromyogram. Balloon inflation increased mean arterial blood pressure 27.9 ± 6.3 mm Hg (mean ± 1 S.D.) during quiet sleep (QS) and 24.4 ± 8.9 mm Hg during active sleep (AS). Behavioral arousal occurred from both sleep states but was significantly ( P < 0.05) delayed during active sleep (21.3 ± 6.7 s) compared to quiet sleep (10.0 ± 3.3 s). This occurred despite there being a greater percent change in R-R interval for a percent change in mean blood pressure during active sleep (2.68 ± 1.08) than during quiet sleep (1.55 ± 0.62). The increase in blood pressure did not produce any significant changes in respiratory rate or integrated diaphragm activity. Thus, acute increases in blood pressure are capable of causing arousal from sleep. This finding should be considered when one discusses the possible mechanisms of arousal from sleep during rapidly developing hypoxemia.

Assessment of vasodilator therapy in patients with severe congestive heart failure: Limitations of measurements of left ventricular ejection fraction and volumes

Although noninvasive techniques are often used to assess the effect of vasodilator therapy in patients with congestive heart failure, it is unknown whether changes in noninvasively determined left ventricular ejection fraction, volume, or dimension reliably reflect alterations in intracardiac pressure and flow. Accordingly, we compared the acute effect of sodium nitroprusside on left ventricular volume and ejection fraction (determined scintigraphically) with its effect on intracardiac pressure and forward cardiac index (determined by thermodilution) in 12 patients with severe, chronic congestive heart failure and a markedly dilated left ventricle. Nitroprusside (infused at 1.3 ± 1.1 [mean ± standard deviation] μg/kg/min) caused a decrease in mean systemic arterial, mean pulmonary arterial and mean pulmonary capillary wedge pressure as well as a concomitant increase in forward cardiac index. Simultaneously, left ventricular end-diastolic and end-systolic volume indexes decreased, but the scintigraphically determined cardiac index did not change significantly. Left ventricular ejection fraction averaged 0.19 ± 0.05 before nitroprusside administration and increased by less than 0.05 units in response to nitroprusside in 11 of 12 patients. The only significant correlation between scintigraphically and invasively determined variables was that between the percent change in end-diastolic volume index and the percent change in pulmonary capillary wedge pressure (r = 0.68, p = 0.01). Although nitroprusside produced changes in scintigraphically determined left ventricular ejection fraction end-systolic volume index and cardiac index, these alterations bore no predictable relation to changes in intracardiac pressure, forward cardiac index, or vascular resistance. Furthermore, nitroprusside produced a considerably greater percent change in the invasively measured variables than in the scintigraphically determined ones.

Variation in the size and distensibility of the pulmonary arteries in d-transposition of the great arteries

The relative size of the main pulmonary artery was determined from cineangiograms of 117 patients with d-transposition of the great arteries by calculating the ratio between the diameters of the main pulmonary artery and aorta. The pulmonary artery was largest in patients with ventricular septal defect or patent ductus arteriosus, or both, because of increased pulmonary arterial pressure and flow. In patients with an intact ventricular septum or with left ventricular outflow tract obstruction, or both, the main pulmonary artery was approximately the size of the aorta. Two cases of d-transposition and gross dilatation of the main pulmonary artery and hypoplastic first branch pulmonary arteries are presented. In these cases the ratio between the diameters of the main pulmonary artery and aorta was greater than in any of the other 117 cases studied. Distensibility of the right pulmonary artery in 18 patients with d-transposition was assessed by determining the percent change in radius and the pressure-strain elastic modulus from the cineangiograms. In patients with intact ventricular septum the distensibility was similar to that reported for normal control subjects, but increased pulmonary arterial pressure due to a ventricular septal defect resulted in stiffer vessels. In comparison with these 18 patients the 2 patients with a grossly dilated main pulmonary artery had an excessively distensible main pulmonary arterial wall as indicated by a greater percent change in radius and abnormal tension-strain relation. Excessive distensibility of the main pulmonary artery and hypoplasia of the first branch pulmonary arteries allowed a greater accommodation of left ventricular stroke volume in the main pulmonary artery and hence resulted in their gross dilatation.

THEORY OF BOREHOLE MAGNETIC SUSCEPTIBILITY MEASUREMENTS WITH COIL PAIRS

The boundary value problem for an axially symmetric configuration of a transmitter‐receiver coil pair in a borehole is considered with particular attention to the “quadrature component” of voltage induced at the receiver coil. It has been known from mathematical expressions previously presented in the literature on induction logging that the quadrature voltage is dependent upon the magnetic permeabilities of the formation and borehole media. The purpose of this investigation was to explore the nature of that dependence in sufficient detail to ascertain some features of its potential usefulness for magnetic susceptibility measurements, particularly of the type contemplated in “Project Mohole.” Although that project is no longer being actively pursued, results of the study are of possible interest in magnetic susceptibility measurements for other purposes, such as geologic correlation. Numerical results from a digital computer program show that the quadrature voltage at the receiver coil is essentially independent of changes in borehole or formation conductivity under the conditions for which the computations were performed. Effects of coil size and the spacing between coils on the quadrature receiver coil voltage were used to determine optimum coil geometry. Analytical expressions valid for small ratios of coil diameter to coil spacing confirm the computer results throughout their domain of validity. An investigation of the sensitivity of the method shows that, when coil geometry is optimum, a given percentage change in κ yields a very slightly greater percentage change in receiver coil voltage. With proper coil spacing, the dependence of receiver coil voltage on κ is very well described by an equation of the form [Formula: see text] where γ is a constant nearly equal to one. This result was verified both analytically and numerically by the calculations from the full expression for voltage.