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[Postcoital IUD insertion, a review].

Following the development of hormonal interception after coitus the post-coital insertion of an intrauterine contraceptive device was proposed by Tatum . The advantage of this treatment is the avoidance of the ingestion of large doses of estrogen which causes much nausea and vomiting although it is a very effective post-coital method of contraception. The recently proposed alternative administration of 200 micrograms Ethynol Estradiol combined with 2 mg of DL norgesterol in 2 equal doses at 12 hour intervals has the same disadvantage of a high percentage of side effects. The post-coital insertion of an intrauterine contraceptive device is the first method which is effective up to five days following unprotected intercourse which is three days longer than treatment by estrogen. In addition the method can be offered to women who would want to continue to wear the intrauterine contraceptive device for long term contraception. The disadvantage of the post-coital insertion of an intrauterine contraceptive device is the ability of serious complications if the patient has a vaginal or venereal infection or an asymptomatic cervicitis or salpingitis. Following appropriate physical examination women who present themselves for post-coital treatment are selected. Cases of rape are usually not suitable for treatment with intrauterine contraceptives devices. However, when cases of rape are seen early enough the appropriate investigations may be done and the treatment with the intrauterine device started within five days. The potential risk of future infertility must be considered since salpingitis is 7 times more common in nulliparous wearers of intrauterine devices than in nulliparous non-wearers. Young sexually active nulliparous women especially of lower socio economic background are patients with a high risk. Over 70% of the women who present themselves for interception treatment are nulliparous.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Comparison of simultaneous invasive and noninvasive measurements of pressure gradients in congenital aortic valve stenosis.

PURPOSE: Congenital aortic valve stenosis is a common problem in pediatric cardiology. The catheter peak to peak systolic gradient is the accepted standard used for prognosis and intervention, but noninvasive correlation in pediatric patients is frequently associated with underestimation or overestimation of this gradient. The purpose of this study was to compare different noninvasive measurements with simultaneous catheter gradients to identify which best predicts the catheter peak to peak gradient. METHODS: Twenty-five simultaneous Doppler and catheter measurements of aortic stenosis gradient were performed in 14 children (all 14 before valvuloplasty and 11 after valvuloplasty). Noninvasive estimates of pressure gradient were compared with catheter measurements with linear regression and Bland-Altman analysis. RESULTS: The Doppler peak instantaneous pressure gradient overestimated the catheter peak to peak gradient but correlated well with the catheter peak instantaneous gradient. The Doppler mean systolic gradient correlated well with the catheter peak to peak gradient at low gradients and underestimated higher catheter gradients but agreed well at all levels with the catheter mean gradient. The modification of a catheter-derived correlation equation produced good correlation with the catheter peak to peak gradient (slope, 1.14; intercept, -1.8; R, 0.92), as did the use of estimated pressure recovery (slope, 1.04; intercept, 5.0; R, 0.94), calculated from a defined fluid mechanic equation. CONCLUSION: The catheter peak to peak gradient can be accurately estimated noninvasively using estimated pressure recovery or correlation equations incorporating Doppler measurements.

Adolescent↗

Effect of acutely increased left ventricular afterload on work output from the right ventricle in conscious dogs.

OBJECTIVE: To determine the effect of acute increments in left ventricular afterload on the stroke work output of the right ventricle in vivo. METHODS: After pharmacologic attenuation of autonomic reflexes, left and right ventricular pressure-volume data were obtained in 9 conscious dogs during vena caval occlusions performed before and during aortic constriction. RESULTS: The relationship between right ventricular stroke work and end-diastolic volume during vena caval occlusion was highly linear (r = 0.97 +/- 0.02), but the slope decreased by 20% +/- 13% during aortic constriction sufficient to increase left ventricular mean ejection pressure by 25% +/- 14% (P <.05). The volume-axis intercept remained constant. Similarly, the slope of the linear relationship between right ventricular free wall regional segment work and end-diastolic segment length declined by 22% +/- 10% during aortic constriction (P <.05), without significant change in the length-axis intercept. The reduction in both global and regional right ventricular stroke work at any given preload with increased left ventricular afterload was due entirely to decreased right ventricular stroke volume and free wall shortening, because right ventricular mean ejection pressure was unchanged. Additional experiments were performed in 5 open-chest dogs to produce a greater reduction in left ventricular free wall shortening than observed with aortic constriction by transient constriction of the left circumflex coronary artery. However, this intervention had no effect on right ventricular free wall segment work output. CONCLUSION: Increased left ventricular afterload decreases global and regional right ventricular stroke work at any given preload, a direct, negative systolic ventricular interaction.

Acute Disease↗

Morphology of nucleolar cistrons in a plant cell, Acetabularia mediterranea.

The structural organization of transcriptionally active DNA that contains cistrons for precursor molecules of ribosomal RNA is described in positively stained spread preparations from nuclei and nucleoli isolated from the green alga, Acetabularia mediterranea Lmx. These nuclei contain large aggregates of nucleolar subunits in which fibril-covered regions, the putative active cistrons for precursors of ribosomal RNA, alternate with fibril-free intercepts, the "spacers." The length distribution of the different intercepts of this DNA is given, and the pattern is compared with those shown in animal cell systems. The data are discussed in relation to problems of transcription and of amplification of ribosomal RNA genes.

Acetabularia↗

Optical properties of etiolated plant tissues.

Etiolated tissues of several plants are multiple bundles of fiber optics capable of coherent transfer of light over at least 20 mm. The acceptance angles (the angles at which light can be intercepted and then internally reflected longitudinally) for mung beans, oats, and corn are 47 degrees , 59 degrees , and 52 degrees -54 degrees , respectively. The shapes of the curves that describe the acceptance angles are the same for various tissues of the same plant but differ between species. The pattern of light transmitted longitudinally through a tissue is dependent on the angle at which the light intercepts the side of the tissue and is strongly influenced by the tissue geometry. When 0.5 mm of the tip is irradiated, the amount of light traveling down the "shaded" side of the coleoptile is equal to or 2- to 3-fold greater than the amount traveling down the "lighted" side.

Journal Article↗

Experimental resolution of the free energies of aqueous solvation contributions to ligand-protein binding: quinone-QA site interactions in the photosynthetic reaction center protein.

Equilibrium binding free energies of 14 benzo-, naphtho-, and anthraquinone cofactors have been determined at the QA redox catalytic site of the purified photosynthetic reaction center protein from Rhodobacter sphaeroides solubilized in water (delta G degrees B,w), in hexane solution containing 30 mM water (delta G degrees B,hh), and after partial dehydration (delta G degrees B,dh) with magnesium sulfate. Our aim is to resolve the contributions of aqueous bulk phase solvation and protein hydration contributions to binding in order to characterize in detail the direct interactions between the ligands and protein at the QA site. This is accomplished by comparing the differences between delta G degrees B,w and delta G degrees B,hh (or delta G degrees B,dh) with the water to hexane solvent transfer free energies of the quinones (delta G degrees tr,Q). Values of delta G degrees tr,Q are determined separately in binary solution and range from 0.65 to -5.69 kcal/mol (1 cal = 4.184 J). The results are interpreted in terms of a thermodynamic cycle that links the species involved in the binding and solvent transfer equilibria. Values of delta G degrees B,hh -delta G degrees B,w are linearly correlated with -delta G degrees tr,Q (slope, 0.78 +/- 0.04; ordinate intercept, -0.13 +/- 0.12 kcal/mol). The deviation of the experimental slopes from the predicted value of unity is attributed in part to a systematic decrease of quinone thermodynamic activity in the aqueous binding medium relative to the aqueous phase in the binary partitioning solvent system. The difference between the quinone-QA site binding free energies measured in hydrated hexane and water is therefore related only to the difference in bulk phase quinone solvation, as given by 0.78 delta G degrees tr,Q. The linear relation obtained using delta G degrees B,dh -delta G degrees B,w has the same slope, but the intercept is decreased to -1.48 +/- 0.19 kcal/mol, indicating that quinone binding strengths in the hexane system are uniformly enhanced after partial dehydration. This suggests that the quinones encounter a common opposition to interaction with the site in the hydrated, relative to the partially dehydrated, state. The further utility of the method to directly assess ligand-site binding free energies is demonstrated with examples that address the contributions of molecular size and dipolar or hydrogen bond interactions to the binding of quinones at the QA site.

Hexanes↗

Optimization of left ventricular fibre orientation of the normal heart for homogeneous sarcomere length during ejection.

UNLABELLED: During the ejection phase of the cardiac cycle, left ventricular muscle fibres shorten while generating force. It was hypothesized that fibres are oriented in the wall such that the amount of shortening is the same for all fibres. We evaluated this hypothesis for the equatorial region of the left ventricle. In a finite element model of left ventricular wall mechanics fibre orientation was quantified by a helix angle which varied linearly from the inner to the outer wall. Fibre length was characterized by sarcomere length, set at 1.95 microns everywhere in the passive state of 0 transmural pressure. For a cavity pressure of 15 kPa, considered representative for ejection, inhomogeneity in mechanical loading was expressed by the variance of the sarcomere length. The variance was minimized by adapting the transmural course of fibre angle. First, only the slope was optimized and in a second optimization this was done for both slope and intercept. Optimal helix fibre angles were 69.6 degrees endocardially, 0 degree at the middle of the wall and -69.6 degrees epicardially for the first optimization and 78.2 degrees, 20.7 degrees and, -36.7 degrees respectively for the second. Sarcomere length changed from 1.95 to 1.975 +/- 0.012 and 1.981 +/- 0.004 microns (mean +/- SD) respectively. CONCLUSION: After optimization calculated helix fibre angles were in the physiological range. Describing the transmural course of fibre angle with slope and intercept significantly improved homogeneity in mechanical load.

Biomechanical Phenomena↗

Nitrogen retention in the pig.

I. Published results have been used to study the relationships between nitrogen retention (NR), body-weight (W) and N intake in the pig. 2. The general decrease in maximal NR (g/d per kg W0.75) with increasing W (kg) was curvilinear for values of W from 1-5 to 45: NR = 3.324--0.098 W + 0.001 W2; and rectilinear for values of W from 45 to 165: NR = 1.252--0.006 W. Values for protein requirements derived from these equations agreed closely with published estimates. 3. The slopes of the curves for NR (g/d per kg W0.75) v. N intake (g/d) decreased as W (kg) increased from about 2.5 to 190. After extrapolation to a proposed common intercept on the NR axis of--150 mg N/d per kg W0.75, regression analysis of the intercepts of these curves on the N-intake axis v. W gave an estimate of N requirements for maintenance of 246 + 19 mg/d per kg W0.75. 4. The results also indicated that at low N intakes net protein utilization (N retention + total obligatory N losses divided by N intake) was essentially independent of W, whereas the gross efficiency of N utilization (NR divided by N intake) was influenced by both W and N intake.

Animals↗

Rumen protein degradation and biosynthesis. I. A new method for determination of protein degradation in rumen fluid in vitro.

A method is described for the determination of protein degradation based on measurements of ammonia concentration and gas production (Menke et al. 1979) when a feedingstuff was incubated with rumen fluid in vitro. NH3 liberated during incubation is in part used for microbial protein synthesis. Production of carbon dioxide and methane can be regarded as a measure of energy available for protein synthesis. The ratio, gas production: incorporation of NH3-nitrogen was estimated by addition of starch to the substrate. The response in gas production was linear in the range 0-200 mg starch, when starch was added to 0-200 mg feedingstuff dry matter and 30 ml rumen fluid-medium mixture. Linear regression between NH3-N concentration (y, mg) and gas production (x, ml) yielded an intercept (bo) representing that amount of NH3-N which would be released when no fermentable carbohydrates were available and consequently no bacterial protein synthesis took place. The difference between this intercept bo and NH3-N content in the blank (rumen fluid without substrate added) indicated the amount of NH3 liberated from protein and other N-containing compounds of the feeding-stuff incubated. In vitro-degradable N (IVDN) was calculated as a proportion of total N by the equation: (formula; see text).

Ammonia↗

Endogenous losses of energy and amino acids in birds and their effect on true metabolisable energy values and availability of amino acids in maize.

1. Endogenous losses of amino acids (EAAL) and energy (EEL) were determined in unfed adult cockerels. The intercepts of linear regression analysis were determined using 44 birds precision-fed on maize. During the experimental period (48 h), excreta of birds were collected, and the samples of maize and the excreta were dried, ground and assayed for gross energy and amino acids. 2. The EAAL and EEL in unfed cockerels influenced true available amino acid (TAAA) values. Therefore, the intercept of regressions showed an increase in TAAA values of maize. 3. The results indicated that there was no significant difference between the data obtained for EEL from the unfed birds and from regression analysis so, the figure from regression analysis could be used for calculating the true metabolisable energy (TME) value of maize. 4. The calculated EAAL from regression analysis caused an increase in the TAAA value in maize. The amounts of metabolic and endogenous amino acid excretions varied in voided excreta from unfed birds. These differences would be related to genetics, age, sex and environmental temperatures.

Amino Acids↗

The effects of hyperbaric air in combination with ethyl alcohol and dextroamphetamine on serial choice-reaction time.

The effects of ethyl alcohol (1.5 ml/kg body weight) and dextroamphetamine (15 mg) on nitrogen narcosis were investigated in two experiments using a 2-, 3- and 4-choice serial reaction time (RT) task with accuracy held constant. Narcosis was induced with air at 6.4 atmospheres absolute (ATA) and a heliox mixture was used as a control. Heliox at 6.4 ATA did not affect RT. Alcohol alone and air at 6.4 ATA increased the intercept of the Hick-Hyman function whereas amphetamine alone decreased it. The increased intercept with air at 6.4 ATA was exacerbated additively by alcohol and ameliorated antagonistically by amphetamine. The slope of the Hick-Hyman function was unaffected. Frequency distributions were shifted as a whole and their shapes were unaltered. It is concluded that these data are consistent with the slowed processing model which proposes that the effects of narcosis on performance are due to a decrease in arousal in conjunction with secondary changes in task strategy.

Adult↗

I Lost It in the Lights: The Effects of Predictable and Variable Intermittent Vision on Unimanual Catching.

In this study, 2 competing views of interceptive action were examined by assessing the influence of variability in the interval between visual samples in a unimanual ball-catching task. Subjects were required to catch tennis balls projected over a distance of 14 m, under conditions of intermittent vision in which the between-sample intervals were either predictable or unpredictable. Results indicated that, although performance was best with shorter between-sample intervals, the temporal predictability of samples did not reliably affect catching performance. This suggests that between-sample retinal expansion provides sufficient information for the timing of the interceptive act.

catching↗

Speed of memory scanning is not affected in early HIV-1 infection.

Thirty-seven nondemented HIV-seropositive and 17 seronegative control subjects were administered the Sternberg speed of memory scanning task, a procedure frequently employed to study mental slowing in patients with subcortical dementing disorders. Experimental and control subjects did not differ in speed of memory scanning, as indexed by the slopes of set size-reaction time functions, nor on mean 0-intercepts for the RT functions, which index stimulus detection and motor response time. Intercept values were significantly greater for subjects with a positive alcohol abuse history and for subjects with greater self-reported depression, but slopes were not significantly correlated with substance abuse history or psychological distress. Cognitive slowing in early HIV-1 infection is not a nonspecific effect observed across all measures of information processing speed. Underlying component functions measured must be carefully considered when selecting reaction time tasks for study with HIV-seropositive subjects. The term "subcortical" dementia may be too general a descriptor, and RT task performance may provide an alternative basis for classification of dementia types.

Acquired Immunodeficiency Syndrome↗

Object rotation effects on the timing of a hitting action.

We investigated how perturbing optical information affects the guidance of an unfolding hitting action. Using monocular and binocular vision, six participants were required to hit a rectangular foam object, released from two different heights, under four different approach conditions, two with object rotation (to perturb the viewed surface area) and two without. Participants made more misses under monocular conditions, and the presence of rotation had a significant effect on the duration between the arm's peak velocity and its contact with the object. We conclude that binocular information contributes to the timing of interceptive tasks. In addition, the guidance of interceptive actions does not appear to be based solely on object expansion information picked up from the viewed surface area.

Adult↗

Sodium balance modulates thirst in normal man.

Several lines of evidence suggest that angiotensin II (AII) plays an important physiologic role in the control of thirst in laboratory animals but a conflicting one in humans. Sodium (Na+) balance plays a key role in the control of the renin-angiotensin system, but studies assessing the effect of sodium balance on thirst perception in humans are limited at best. To address this question, we studied the relationship between thirst perception and plasma osmolality during 5% saline infusion (.08 ml/kg/min x 120 min) in 5 healthy volunteers while in metabolic balance on both a 10 mEq. sodium (LS) and 200 mEq. sodium (HS) diet with and without infusion of AII (5 ng/kg/min). Thirst perception was quantified using a linear visual analogue scale. The relationship between serum Na+ (a measure of osmolality) and thirst perception was analyzed using linear regression. The mean x-intercept ([Na+] mEq/l) which represents the osmotic threshold to thirst was 138.2 +/- 0.5 in LS vs 140.7 +/- 0.8 in HS, p < 0.05. We conclude that the osmotic threshold for thirst is lower in LS (high endogenous AII) vs HS (low endogenous AII). There was no evidence for substantial extracellular volume change in HS vs LS with no significant differences in weight, hematocrit or total serum protein. Acute AII infusion did not result in changes in slope or x-intercept, but the pressor response to exogenous AII may have inhibited its dipsogenic effect (as has been shown in animal studies). These data suggest a physiologic role of sodium balance (possibly mediated via endogenous AII) in the control of thirst in normal humans.

Aldosterone↗

Effectiveness of DTPA treatments following the injection of particulate plutonium.

A limited long-term experiment has been completed in which the chronic toxicity resulting from a single intravenous injection of 31.4 kBq of a poly-disperse 239Pu colloid sol per kg of body weight was tested in Beagle dogs. The Pu deposited mostly in the phagocytic cells of liver, spleen and to a lesser degree in lung and bone marrow. Slow solubilization of the Pu particles by endogenous ligands caused translocation of the nuclide and redeposition mostly as monomeric Pu in the skeleton and in liver hepatocytes. Thus, the deposit behaved as expected from a pulmonary or wound contamination in humans with a moderately soluble depot of Pu such as Class W hot particles. Therefore, this type of deposit provided the basis for a practical model to study the ensuing radiation effects under various experimental conditions. The dogs were divided into three groups of four animals each, and the following conditions were applied: (a) no further treatment was given, allowing free translocation of the Pu to its secondary deposition sites; (b) interception of the Pu translocation by weekly injections of 30 mumol of Ca-DTPA/kg of body weight (Ca-chelate of diethylene-triaminepentaacetic acid); and (c) interception of translocation by daily injections of 30 mumol/kg body weight of Zn-DTPA. For each of the groups (b) and (c), three dogs were used in a lifetime study, and one was sacrificed for nuclide distribution studies. Free translocation and subsequent deposition in the skeleton resulted in the death of each of the non-chelated dogs from osteosarcoma between 1267 and 1594 days after injection. Weekly treatment with Ca-DTPA reduced the total Pu burden significantly, but these dogs also died with osteosarcoma between 1462 and 1783 days. Daily injections with Zn-DTPA reduced the total Pu burden more efficiently than Ca-DTPA and prevented continuous deposition of solubilized Pu on bone surfaces. The mean post-injection survival of these dogs was 3520 days or about 2.1 times that of the animals receiving Ca-DTPA, while the latent period for bone tumour induction was about 2.6 times longer. This treatment reduced the severity of liver lesions and eliminated the occurrence of persistent leukopenia, but it did not prevent the formation of bone cancer.

Animals↗

Improved determination of variant erythrocytes at the glycophorin A (GPA) locus and variant frequency in patients treated with radioiodine for thyroid cancer.

Red blood cells from individuals with the blood group MN express each form of the allelic GPA protein (GPAM and GPAN) on their cell surface. Variant cells have lost one form of the protein. Their frequency is about 10(-5) in blood from unexposed persons. The BR6 assay is currently the most widely used assay to determine variant frequency (VF) by immunolabelling and flow cytometry. The precision of the BR6 assay is mainly limited by the Poisson error because only small numbers of variant cells are detected in each assay. The BR6 assay has been improved by magnetic cell separation (MACS) of variant erythrocytes prior to their determination by this assay. This new version of the assay is named 'MACS-BR6'. It allows enumeration of variant cells from 2 x 10(8) or more blood cells instead of 5 x 10(6) in the BR6 assay with a precision which is about 5 times higher than that of the BR6 assay. The MACS-BR6 assay was used to determine the VF of GPAN/0 and GPAN/N variant cells in 12 healthy adults and 11 patients treated with radioiodine for thyroid cancer 2 to 16 years before. The average red bone marrow dose was 347 mGy. In healthy adults the mean VF of GPAN/0 and GPAN/N variant cells was 16.1 x 10(6) and 5.3 x 10(-6) respectively. In patients the corresponding mean VF was 25.4 x 10(6) and 11.9 x 10(-6), respectively. The patients GPAN/0 VF was significantly higher than that of controls. In patients VF increases linearly with the dose. The linear regression parameters of VF were 16.6 x 10(-6) (intercept), 23.7 x 10(-6) GY-1 (slope) and 6.3 x 10(-6) (intercept), 12.9 x 10(-6) Gy-1 (slope) for GPAN/0 and GPAN/N variant cells, respectively.

Adult↗

A study of methods to reduce groundwater contamination around the Kimpo landfill in Korea.

Four different methods were studied to reduce the groundwater contamination around the Kimpo landfill in Korea by leakage of a leachate. The hydraulic parameters were measured for this study and then the groundwater flow and contaminant transport systems around the Kimpo landfill were simulated with MODFLOW and MT3D models. Both the method of establishing 5 sets of Radial Collector Well Laterals (RCWLs) within the landfill and a method utilizing the wells for dewatering condensed water brought about a 70% leachate elimination efficiency. Their construction costs were cheap, and the maximum concentrations of chloride and phenol in the leachate effluent were high. Meanwhile, a method establishing an interception wall to the 2nd layer at the cirumference of the landfill and 22 sets of RCWLs within it brought about a 92% leachate elimination efficiency. Its construction cost was expensive, and the maximum concentrations of chloride and phenol in the leachate effluent were low. A method of establishing an interception wall to the 3rd layer and 40 sets of RCWLs brought about a 97% leachate elimination efficiency. Its construction cost was the most expensive, and the maximum concentrations of chloride and phenol were low. Conclusively, a method of establishing 22 sets of RCWLs was evaluated as the most stable and economical option to reduce groundwater contamination concentration below drinking water standard.

Cost-Benefit Analysis↗