Dissociation and posttraumatic stress disorder in Vietnam combat veterans.

Objective: This study compared current dissociative symptoms and dissociation at the time of specific traumatic events in Vietnam combat veterans with posttraumatic stress disorder (PTSD) and Vietnam combat veterans without PTSD.

Method: Vietnam combat veterans who sought treatment for PTSD (N = 53) were compared to Vietnam combat veterans without PTSD (N = 32) who sought treatment for medical problems. Dissociative symptoms were evaluated with the Dissociative Experiences Scale.

Regulation of assimilatory nitrate reductase activity in soil by microbial assimilation of ammonium.

It is well established that assimilatory nitrate reductase (ANR) activity in soil is inhibited by ammonium (NH4+). To elucidate the mechanism of this inhibition, we studied the effect of L-methionine sulfoximine (MSX), an inhibitor of NH4+ assimilation by microorganisms, on assimilatory reduction of nitrate (NO3-) in aerated soil slurries treated with NH4+. We found that NH4+ strongly inhibited ANR activity in these slurries and that MSX eliminated this inhibition.

Magnetic resonance spectroscopy studies on experimental murine and human tumors: comparison of changes in phosphorus metabolism with induced changes in vascular volume.

The responses of two experimental murine tumors and two human tumor xenografts to the vasodilator hydralazine were compared using two magnetic resonance spectroscopy endpoints. Changes in tumor metabolism were determined using 31P MRS where inorganic phosphate levels relative to total phosphate (Pi/total) were measured, and alteration in tumor blood volume was examined using 19F MRS with perfluorooctylbromide (PFOB) as tracer. The integrated 19F signal from PFOB is dose dependent and stable for at least 2 hr after injection.

Bioreductive drugs as post-irradiation sensitizers: comparison of dual function agents with SR 4233 and the mitomycin C analogue EO9.

Various bioreductive drugs that are potent hypoxic cell cytotoxins can also function as effective potentiators of radiation action when administered in vivo post irradiation. There is evidence that a contributory mechanism to this potentiation is enhanced sensitivity to the bioreductive drugs exhibited by cells that are damaged sublethally by radiation.

Sensitivity to viewpoint in children's drawings of objects and relations between objects.

Previous literature suggests that young children are relatively insensitive to viewpoint, only showing their view when the task is manipulated to provoke it. In contrast, older children appear to become more sensitive to viewpoint and it has been claimed that there is a developmental progression toward use of linear perspective as a means of drawing a view-specific scene. This study investigates sensitivity to viewpoint by manipulating it directly.

In vivo 31P nuclear magnetic resonance spectroscopy of experimental murine tumours and human tumour xenografts: effects of blood flow modification.

The effect of hydralazine on tumours appears to vary depending on tumour type. Blood flow and radiation sensitivity decrease more in murine tumours than human tumour xenografts. In this study a comparison between various tumour types has been made using in vivo 31P nuclear magnetic resonance spectroscopy (NMRS) to follow the metabolic responses occurring after clamping or intravenous administration of hydralazine (5 mg kg-1).

Hypnotic efficacy of estazolam compared with flurazepam in outpatients with insomnia.

Estazolam is a new benzodiazepine hypnotic agent with an intermediate half-life of 12 to 15 hours. The authors designed an investigation to compare its hypnotic efficacy to that of flurazepam, generally considered the reference standard. The hypnotic efficacy of estazolam at two doses (1 mg and 2 mg) was compared with that of flurazepam (30 mg) in a double-blind, placebo-controlled, multicenter, 7-night study that involved 223 outpatients with insomnia.

Form perception at birth: Cohen and Younger (1984) revisited.

Cohen (1988; Cohen & Younger, 1984) has suggested that there is a shift in the perception of form sometime after 6 weeks of age. Prior to this age infants can remember the specific orientations of line segments, but cannot process and remember the angular relations that line segments can make. Experiment 1 used simple line stimuli with newborn infants to test this suggestion.

The measurement of radiosensitizer-induced changes in mouse tumor metabolism by 31P magnetic resonance spectroscopy.

Flunarizine and nicotinamide have previously been shown to increase blood perfusion to experimental mouse tumors and consequently, to increase their sensitivity to X rays. These agents were examined for their ability to alter metabolism, measured by 31P magnetic resonance spectroscopy, in the SCCVII/Ha carcinoma and the KHT sarcoma. Flunarizine at 5 mg/kg I.

Induction of hypoxia in the KHT sarcoma by tumour necrosis factor and flavone acetic acid.

The interaction of FAA or TNF with radiation was studied in the murine KHT sarcoma. When used alone both agents showed a dose- and time-dependent toxicity towards the tumour cells and significantly reduced tumour blood flow within 1 h of treatment. When used in combination with radiation, both TNF and FAA caused an increase in the fraction of hypoxic cells in the KHT tumour.

Bioreductive drugs and the selective induction of tumour hypoxia.

In this work tumour hypoxia is induced by physically occluding the tumour vascular supply by clamping, or by giving mice 5 mg kg-1 hydralazine. These methods have previously been shown to increase the radiobiological hypoxic fraction in tumours close to 100%. Their effectiveness in potentiating the bioreductive toxicity of: misonidazole (800 mg kg-1), RSU1069 (80 mg kg-1), mitomycin C (5 mg kg-1) and SR4233 (50 mg kg-1) is assessed in the RIF-1 and KHT tumours using regrowth delay as an assay.

Phytotoxicity of foliar-applied urea.

Recent work in our laboratory showed that the adverse effect of urea fertilizer on seed germination and seedling growth in soil is due to ammonia produced through hydrolysis of urea by soil urease (NH(2)CONH(2) + H(2)O --> 2NH(3) + CO(2)) and can be eliminated by amending the fertilizer with a small amount of a urease inhibitor such as phenylphosphorodiamidate. Because the leaf-tip necrosis often observed after foliar fertilization of plants with urea is usually attributed to ammonia formed through hydrolysis of urea by plant urease, we studied the possibility that this necrosis could be eliminated or reduced by adding phenylphosphorodiamidate to the urea fertilizer. We found that, although addition of this urease inhibitor to foliar-applied urea increased the urea content and decreased the ammonia content and urease activity of soybean [Glycine max.

Evidence that the adverse effect of urea fertilizer on seed germination in soil is due to ammonia formed through hydrolysis of urea by soil urease.

Studies using seeds of wheat (Triticum aestivum L.), rye (Secale cereale L.), barley (Hordeum vulgare L.

Potential phytotoxicity associated with the use of soil urease inhibitors.

Recent work in our laboratory showed that the adverse effect of urea fertilizer on seed germination and seedling growth in soil is due to ammonia produced through hydrolysis of urea by soil urease (NH(2)CONH(2) + H(2)O --> 2NH(3) + CO(2)) and can be eliminated by amending the fertilizer with a small amount of a urease inhibitor such as N-(n-butyl)thiophosphoric triamide or phenylphosphorodiamidate. Continuation of this work showed that these inhibitors can induce leaf-tip necrosis in plants. Research to account for this phytotoxicity indicated that it resulted from an accumulation of toxic amounts of urea in plants through inhibition of urease activity by N-(n-butyl)thiophosphoric triamide and phenylphosphorodiamidate.

Perceptual and intellectual development in infancy.

The conventional view of development in human infancy is that objective awareness of the surrounding world is gradually constructed during the first 2 years through the infant's actions on the environment. However, recent work on the perceptual abilities of young infants indicates that even newborns perceive objective properties of their surroundings, detecting depth and displaying perceptual constancies that have hitherto been attributed only to older infants. In consequence it is necessary to revise our model of infant development.

Elimination of the adverse effects of urea fertilizer on seed germination, seedling growth, and early plant growth in soil.

The rapidly increasing importance of urea fertilizer in world agriculture has stimulated research to find methods of reducing the problems associated with the use of this fertilizer. One of these problems is that urea has adverse effects on seed germination, seedling growth, and early plant growth in soil. Because there is evidence that these adverse effects are caused largely, if not entirely, by ammonia produced through hydrolysis of urea fertilizer by soil urease, we explored the possibility that they could be reduced or eliminated by amending urea fertilizer with a small amount of a urease inhibitor.

The influence of pre-treatment temperature on the thermal sensitivity of a mouse tumour.

The response of tumours to hyperthermia was tested by giving graded heat treatments and assessing local control at 90 days. Mice were divided into three groups which were pre-treated for 3 days in ambient temperatures of 4, 21 or 35 degrees C. This enabled the mean tumour resting temperature to be varied by up to 11 degrees C, before subsequent heat treatment.

An immunotoxin composed of monoclonal anti-Thy 1.1 antibody and a ribosome-inactivating protein from Saponaria officinalis: potent antitumor effects in vitro and in vivo.

The ribosome-inactivating protein saporin, from Saponaria officinalis, was coupled by a disulfide bond to monoclonal anti-Thy 1.1 antibody (OX7) and to its F(ab')2 fragment. The immunotoxins were at least as toxic as the plant toxin ricin to the Thy 1.