Dynamics of metal accumulation in the grasshopper Chorthippus brunneus in contaminated grasslands.
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Animals↗
Biomedical subjects
D J Thompson
Publications and source records attributed to D J Thompson.
No episiotomy?!
A method is presented which with careful manipulation of the vagina around the crowning head reduces the incidence of an episiotomy or a perineal tear. Using the method described, the overall result obtained was an intact perineum in 68% of vaginal deliveries (which included forceps deliveries). An episiotomy was performed in only 7% of deliveries--all associated with the use of forceps.
Episiotomy↗
Hysterical personality disorder. The process of diagnosis in clinical and experimental settings.
A study of the case notes of 52 patients with a diagnosis of hysterical personality disorder showed that 27 had no recorded features of that condition, but were frequently described as aggressive, uncooperative, or attention-seeking. Although 60% were recorded as depressed, only 17% received antidepressant treatment. In an experimental study, the core traits of the disorder were found to have a low inter-rater reliability. Two patients, who had received hospital diagnoses of hysterical personality disorder, were shown to display behaviour that caused psychiatrists to make a diagnosis on wholly inadequate information.
Adult↗
Effects of hydrocortisone on carbohydrase concentrations, de novo synthesis and turnover patterns in immature rat intestine.
Hydrocortisone administration to infant rats enhanced cellobiase and maltase activities and induced precocious expression of sucrase and trehalase activities along the length of the small intestine. These activity changes reflected proportional concentration increases in the enzymes lactase (EC 3.2.1.23), maltase/glucoamylase (EC 3.2.1.20) and sucrase-isomaltase (EC 3.2.1.48/10). Administration of an equivalent tracer dose of [3H]leucine (by body weight) to control and hydrocortisone-treated infant rats resulted in greater accumulation of label in the carbohydrase pools of the treated rats, suggesting their increased de novo synthesis. The increased concentrations of lactase and maltase/glucoamylase induced by exogenous hydrocortisone were matched by the presence of corresponding greater amounts of label in their brush border pools. Accumulation of label in each of the lactase, maltase/glucoamylase and sucrase-isomaltase pools was generally similar in the hydrocortisone-treated rats, suggesting equivalent stimulation of their synthesis as a group by the humoral agent. The turnover rates of the carbohydrases as a group were found to be similar and did not appear to differ in control and hydrocortisone-treated rats. Total protein synthesis rates were slightly greater in the intestine of the hydrocortisone-treated group of rats.
Aging↗
Residual embryos in failed embryo transfer.
One hundred thirteen embryo transfers (ETs) were performed in an in vitro fertilization and ET program of which residual or extruded embryos were found in 17 transfers (15%). Residual or extruded embryos are those embryos found outside the uterine cavity, either at the cervical os, on the vaginal speculum, or remaining in the catheter after an ET. Patients were divided into two groups according to the method of inspection for residual embryos. In group I, microscopic visualization of the transfer catheter alone revealed that 9 of the 67 transfers (13.4%) had 17 residual embryos either at the catheter tip or adherent to mucus on the side of the catheter. In group II inspection of the catheter and cervical wash revealed that 8 of 46 ETs (17.4%) had 15 residual embryos that failed to be transferred during the initial attempt. Six of these 15 (40%) were found in the cervical wash medium. Thus, failure of the proper placement of embryos at the time of transfer may occur frequently. Evaluation of only the transfer catheter may result in a significant underestimation of the problem.
Animals↗
Digital instrument for measurement of aural acoustic immittance: a preliminary report.
Development of techniques for measurement of aural acoustic immittance (AAI) is reviewed. Measurement characteristics of selected AAI instruments are compared. Real-ear data obtained with a digital instrument are presented. Review of data support the suggestion that digital AAI instruments promote development of quantitative measurement protocols with greater efficiency and power.
Acoustic Impedance Tests↗
Wolfe mammographic parenchymal patterns. A study of the masking hypothesis of Egan and Mosteller.
Wolfe defined four different classes of breast parenchymal patterns and claimed that they were associated with different risks for the subsequent development of breast cancer. Egan and Mosteller suggested that these patterns did not constitute a true risk factor, rather the effect was caused by the greater difficulty of detecting breast cancers in the dense (P2, DY) patterns compared with the fatty (N1, P1) patterns. Similarly, Mendell believed that a bias was introduced into Wolfe's work by requiring a negative mammogram before a patient entered the study. This study of 221 prevalent and 706 incident cancers followed for up to 10 years indicates that a masking effect does exist, but that it operates in addition to a difference in risk of breast cancer within the four Wolfe classes. Wolfe's hypothesis is found to be valid.
Breast Neoplasms↗
The effect of prenatal procarbazine treatment on brain development in the rat.
Groups of pregnant Sprague-Dawley rats were treated orally with procarbazine, an antineoplastic drug, at dose levels of 0, 1.0, 2.5, 5.0, 7.5, and 10.0 mg/kg/day from days 12 through 15 of gestation. Following normal delivery, offspring were raised until day 21 and sacrificed, and their brains removed and weighed. A dose-dependent micrencephaly, characterized by hypoplasia of the cerebral hemispheres, was seen starting at 2.5 mg/kg/day. In a second study, groups of pregnant female rats were given a single dose of 10 mg/kg procarbazine on gestation day 12, 13, 14, or 15. Micrencephaly occurred in 21-day-old offspring from all groups, with the greatest effect induced on days 13, 14 and 15. Analysis of brain region weights revealed a maximum reduction in neocortex weight in offspring from groups treated on days 13 and 14. The hippocampus, cerebellum, and diencephalon-midbrain were also reduced in size, depending on the day of treatment, while the corpus striatum and pons-medulla were spared. In a final study, embryos from females treated on gestation days 12 through 15 were removed, fixed, and sectioned at 24-hour intervals starting on gestation days 13. Necrosis and cellular degeneration were observed with decreasing severity in the telencephalon, diencephalon, mesencephalon, and medulla. The neocortex of 20-day treated fetuses was characterized by a thickening of the ventricular zone and reduced cellularity of the cortical plate.
Aging↗
The relationship between Wolfe's classification of mammograms, accepted breast cancer risk factors, and the incidence of breast cancer.
Data collected between 1973 and 1984 on 696 incident cases of breast cancer and 1,376 matched controls from four Breast Cancer Detection Demonstration Project clinics in the United States were used to assess the role of mammographic parenchymal pattern as a risk factor and its relationship with other, accepted, risk factors. The data confirm previous reports of the influence of benign breast biopsy, age at first live birth, family history of breast cancer, and duration of menstruation on the incidence of breast cancer. Height is also found to be an influential factor. Parenchymal pattern is found to be a risk factor with effects comparable in magnitude to the other factors studied. It operates separately from them, except for its relationship with height and weight. After adjustment for parenchymal pattern, weight is seen to have a significant effect on breast cancer incidence, and height is no longer needed in a model for risk. A model which simultaneously incorporates all of the risk factors considered, including parenchymal pattern, is presented. While these factors are of interest in the epidemiology of breast cancer, it is demonstrated that they are insufficient to allow reliable prediction of the disease in an individual woman.
Body Height↗
The neuroteratogenicity of procarbazine in the rat: behavioral, morphological, and neurochemical aspects.
Pregnant female Sprague-Dawley rats were treated from day 12 through day 15 of gestation with procarbazine, an antineoplastic drug, and their offspring were subjected to tests of locomotor development and behavior. Treatment levels ranged from 0.5 mg/kg/day, a dose that produced no abnormalities, to 10 mg/kg/day, a dose that caused a marked micrencephaly in the absence of other teratological changes. Despite marked morphological brain changes, preweaning locomotor development, as assessed by open-field swimming activity and vertical grid climbing, was normal in all offspring. Post-weaning passive avoidance learning and retention were also normal. Groups that had been treated prenatally with teratogenic doses (5.0 and 10.0 mg/kg/day) displayed less rearing behavior in the open field, while ambulation in the periphery of the open field arena was unaffected. Groups treated with subteratogenic doses (0.5 and 1.0 mg/kg/day) did not differ from control. In addition to the behavioral studies, sodium-dependent high-affinity choline uptake and choline acetyltransferase activity (CAT) were measured (per mg protein) in the cortex and hippocampus of animals that had been exposed prenatally to either teratogenic or subteratogenic doses of procarbazine. In spite of a substantial reduction in size of both brain structures in the group receiving a teratogenic dose, choline uptake and CAT did not differ from control.
Abnormalities, Drug-Induced↗
Reproduction and teratology studies on hexamethylmelamine in the rat and rabbit.
The antineoplastic drug hexamethylmelamine (HMM) was evaluated for effects on reproduction and postnatal development in the rat and on embryonal and fetal development in the rat and rabbit. Daily po treatment of male rats for 62 days with doses of 0, 10, 20, or 40 mg/kg/day resulted in testicular atrophy, reduced fertility, and a possible dominant lethal mutagenic effect at the higher two dose levels. Alterations in morphology and function of the beta cells of the pancreatic islets were observed after treatment of males for more than 28 days with 20 or 40 mg/kg/day. The same dose levels administered to female rats for 14 days prior to breeding and through Day 13 or 20 of gestation had no adverse effects on fertility, but the highest dose was embryocidal and postnatal survival was decreased at both the 20- and 40-mg/kg/day dose levels. Similar effects on postnatal survival were observed when the drug was administered by gavage to rats during the last week of gestation and throughout the lactation period. Treatment of pregnant rats throughout organogenesis (Days 6 to 15) or for 4-day intervals during organogenesis (Days 6 to 9, 9 to 12, or 12 to 15) with po doses ranging from 20 to 80 mg/kg/day resulted in decreased body weight gain and food consumption, an increased resorption rate in dams receiving 80 mg/kg/day on Days 6 to 9, and decreased fetal weights at all dose levels and most treatment intervals. The incidence of minor skeletal defects was increased among litters of HMM-treated groups. Major fetal malformations were limited in number but were considered treatment related. Treatment of pregnant rabbits po on Days 6 to 18 of gestation with doses of 0, 20, 40, or 60 mg/kg/day did not result in an embryocidal or teratogenic effect. Treatment with 60 mg/kg/day did, however, result in decreased kit weights, indicating a mild embryo-fetotoxic effect.
Abnormalities, Drug-Induced↗
Pancreatic beta cell vacuolation in rats after oral administration of hexamethylmelamine.
The effects of hexamethylmelamine (HMM) on morphology and function of the endocrine pancreas were investigated following the induction of a diabetic-like syndrome in a reproduction study in rats. Doses of 0, 20, 40, or 80 mg/kg/day were administered once daily, by gavage, to groups of 10 male and 10 female Sprague-Dawley rats for up to 77 days. Signs of toxicity were observed at all treatment levels and were of such severity at 80 mg/kg/day that this group was terminated after 8 days of treatment. Measurement of serum glucose levels revealed a dose- and time-related hyperglycemia in rats from the 20- and 40-mg/kg/day groups with levels exceeding 700 mg/dl in some rats after 77 days of treatment. Reversal of the hyperglycemia after discontinuing treatment with HMM occurred in some rats receiving 20 mg/kg/day, whereas the effects of higher doses were still present following a 2-month recovery period. Microscopically, there were hydropic degeneration of renal tubular epithelium and vacuolation of pancreatic beta cells. Ultrastructurally, vesiculation of the Golgi-smooth membrane reticular complex and a marked reduction in the number of insulin granules were observed. It appeared that HMM exerted a disruptive effect on the production of insulin at or prior to the level of the Golgi complex. The severity and time course of morphologic changes and hyperglycemia were dependent on dose and duration of treatment.
Administration, Oral↗
Teratology and reproduction studies with triclopyr in the rat and rabbit.
Triclopyr (3,5,6-trichloro-2-pyridyloxyacetic acid), being developed as a new herbicide for use on brush and weeds, was evaluated for its potential effects on reproduction, and embryonal and fetal development. Pregnant Sprague-Dawley rats were given doses of 0, 50, 100, or 200 mg/kg/day by gavage on Days 6 through 15 of gestation. Dose-related signs of maternal toxicity were observed during the treatment period. No teratogenic effects were observed at any dose level, though slight fetotoxicity, possibly secondary to maternal toxicity, occurred at the high dose level (200 mg/kg/day). Pregnant New Zealand White rabbits were given doses of 0, 10, or 25 mg/kg/day by gavage on Days 6 through 18 of gestation which produced transient, dose-related decreases in maternal body weight gain. However, there were no indications of any treatment-related effects on fetal growth and development among rabbits. Male and female Sprague-Dawley rats maintained on diets supplying 0, 3, 10, or 30 mg/kg/day over three generations exhibited no consistent treatment-related effects on reproductive performance, pregnancy, parturition, or neonatal survival. These data indicated that triclopyr had little or no potential for teratogenic or reproductive toxicity even when the level of exposure approached that which elicited maternal toxicity.
Abnormalities, Drug-Induced↗
Transcranial conduction of acoustic-reflex-eliciting signals.
Conduction of a broad-band signal from a supra-aural earphone to an acoustic-immittance instrument coupled to the contralateral ear canal was studied using three commercial immittance instruments. Results indicated that portions of the broad-band signal reached the contralateral ear canal at presentation levels of 100-110 dB SPL. At levels as low as 100 dB SPL, the signal was detected by at least one of the acoustic-immittance instruments. At higher sound pressure levels the transmitted signal caused deflections of the acoustic-immittance meter similar to those associated with an acoustic-reflex response. However, these artifacts could be differentiated from acoustic-reflex responses in several respects and could be prevented by high-pass filtering of the broad-band test signal.
Acoustic Impedance Tests↗
In vivo cytogenetic study in rats maintained for eight days on diets containing probucol.
Probucol (4,4'-(isopropylidenedithio)bis(2,6-di-t-butylphenol], a cholesterol-lowering drug, was evaluated for cytogenetic toxicity in the bone-marrow cells of Sprague-Dawley rats. Male and female rats were fed diets containing 0, 200, 400, or 800 mg/kg body weight/day for 8 consecutive days. Animals treated with trimethylphosphate served as positive controls. Femoral bone-marrow specimens were aspirated from all animals for cytogenetic evaluation. Analysis of the data generated by this study indicated that the incidence of cytogenetic aberrations in the bone marrow of rats was not affected by administration of probucol within the present treatment regimen.
Administration, Oral↗
Reproducibility and consistency in classification of breast parenchymal patterns.
The Wolfe Classification System of evaluating risk of developing breast cancer from analysis of mammographic parenchymal patterns (MPP) has received worldwide attention. In addition to confirming its validity, it is necessary to establish the ability of radiologists to apply the classification of mammograms consistently and reproducibly. This paper reports the results of 12 radiologists associated with the former Breast Cancer Detection Demonstration Projects (BCDDP) in Ann Arbor, Honolulu, Seattle, and Tucson. The participating radiologists had all had some experience with classifying mammograms, then were exposed to more intensive instruction, and finally worked with atlases developed at each institution. The results reported here show the comparisons of the radiologists' readings with Dr. Wolfe in a series of three separate exercises and also three tests of intraobserver consistency. Two of the participating institutions used xeromammograms and two, film mammograms. The study was designed and supervised by an independent data coordinating center with masking of mammograms, without benefit of information of previous readings and no information available except age. The results indicate that this group of radiologists could classify mammograms in the method of Wolfe at an acceptable level compared to other similar exercises.
Breast Neoplasms↗
Hydronephrosis of pregnancy: a prospective sequential study of the course of dilatation.
The kidneys of 20 asymptomatic pregnant women were examined sequentially from the first trimester through the postpartum period. In 41.5 per cent, progressive dilatation, more marked on the right side, was seen; however, the remainder demonstrated varying, static, or even diminishing ectasia. In all but two dilatation had reverted to normal by six weeks post partum. The finding of minimal dilatation speaks against pathologic obstruction even in the symptomatic patient. Asymptomatic patients can, however, show variable degrees of hydronephrosis with progression or regression through the course of gestation. The finding of dilatation must be interpreted with caution by virtue of these sequential variations.
Dilatation, Pathologic↗
Accelerators for generating synchrotron radiation.
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Electrons↗