The influence of the estrous cycle, persistent estrus, ovariectomy and estrogen replacement, on the numbers and frequency of spontaneously active neurons in slices of the rat preoptic region in vitro

Spontaneous single-unit activity was studied in the preoptic region of rat brain slices. Similar unit frequencies were recorded during the estrous cycle and for all ovariectomized (OVX) rats (median frequencies between 0.8 and 2.0 Hz). Higher frequencies were recorded in persistent estrus (PE) (median 3.5 Hz) and in males (median 3.4 Hz), P vs estrus less than 0.001. The mean percentage of tracks with units was low at estrus (15%), at diestrus (18%), in OVX rats (16%) and male rats (22%), and was significantly increased in metestrus (36%) and proestrus (33%) (P vs estrus less than 0.01) and in OVX rats after estrogen treatment (P less than 0.05 to P less than 0.01). It is suggested that the increased number of units found in OVX rats after estrogen treatment and in PE rats are both effects of prolonged elevated levels of estrogen in the brain.     

Effect of collagen denaturation on the toughness of bone

The purpose of this study was to explore the relationship between the integrity of collagen and biomechanical properties of bone. In this study, age (range, 5-26 years old) and gender related changes in cortical bone samples from 33 baboon femurs (15 males and 18 females) were examined. The percentage of denatured collagen was determined using a selective digestion technique. The fracture toughness, elastic modulus, yield and ultimate strength, and energy to fracture of bone were determined in three-point bending configurations. The porosity and weight fractions of the mineral and organic phase also were measured. A two-way analysis of variance showed that age dependent changes were reflected primarily in the amount of denatured collagen, fracture toughness, energy to fracture, and elastic modulus, whereas gender had effects on the fracture toughness, elastic modulus, and porosity of bone. In addition, regression analyses indicated that the percentage of denatured collagen had an inverse correlation with the toughness of bone and a positive correlation with its elastic modulus, whereas mineral content had positive correlation with the strength and elastic modulus of bone. The results of this study suggest collagen influences the toughness of bone, whereas mineral content predominantly contributes to bone stiffness and strength.     

Differentiation of benign from malignant breast disease associated with screening detected microcalcifications using dynamic contrast enhanced magnetic resonance imaging

Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) is an effective diagnostic modality for symptomatic breast disease. However, its role in evaluating clinically occult disease associated with mammographically detected microcalcification remains unclear. Women recalled following screening mammography with microcalcification had DCE-MRI examination of the breast. The data were evaluated subjectively and objectively using both empirical and 2-compartment pharmacokinetic modelling techniques to evaluate signal intensity parameters. Eighty-eight patients aged 50-75 years (median 58) were recruited. Comparing malignant and benign lesions, the mean values in arbitrary units for the enhancement index at 1 min in the most enhancing 9-pixel square +/-1 standard deviation were 0.61+/-0.40 vs. 0.22+/-0.26 p=<0.001 with sensitivity, specificity, PPV, NPV and accuracy of 80.0%, 82.4%, 57.1%, 93.3% and 81.8%, respectively. The corresponding values attained by the radiologist were 75.0%, 89.7%, 68.2%, 92.4% and 86.4%. DCE-MRI is able to differentiate malignant from benign clinically occult lesions associated with microcalcification and may therefore offer an alternative to open surgical biopsy for women with equivocal findings following initial triple assessment for microcalcification in the breast.     

Suicide facts and myths: A study of prevalence

Abstract

Although statements regarding “myths” about suicide are common in the literature, few empirical investigations have been conducted to determine the extent to which such “myths” are believed. A 32-item questionnaire concerning demographic and clinical correlates of suicidality was administered to 271 college students. Past history of personal suicidal behavior and that of others known to the subjects were also determined. In general, performance was poor with an average score of 59.1 percent, or 18.9 items correctly answered. Subjects with the following characteristics performed best (though still at generally low levels): those with training in suicide prevention or crisis intervention, those with some educational experience about suicide, older students, those with higher college class standing and those enrolled in upper level college courses. In a second study, 49 home health care personnel and 32 individuals being trained to do outreach work with the elderly were given a 16-item subset of the 32-item questionnaire above. Performance was high (approximately 75 percent correctly answered). Nearly all of these items were clinical in nature and were comprised primarily of the “myths” traditionally discussed in the suicide literature. While performance on factual/demographic information was poor in the first study, both investigations found performance on clinical, traditional “myths” about suicide to be high. The implications of these findings for training and education are discussed.     

Reduced Chemotherapy Duration: A Good Idea?

Over the past three decades, survival outcomes of high-risk stage II and stage III colon cancer have improved with the use of adjuvant chemotherapy. Oxaliplatin and fluoropyrimidine combination regimens, given for 6 months, are the current standard of care. However, chronic peripheral neuropathy can result as a side effect of oxaliplatin use. Investigators have questioned whether the recommended duration of adjuvant therapy is necessary. This review discusses the history of adjuvant therapy for colon cancer and provides a rationale for an ongoing clinical trial collaboration addressing the optimal duration of adjuvant therapy.     

Assessment of macronutrient and micronutrient intake in women with anorexia nervosa

OBJECTIVE: The purpose of this study is to evaluate the accuracy of diet history compared to observed food intake in the nutritional assessment of women with anorexia nervosa (AN) and healthy age-matched controls. METHOD: One-month diet history was compared to 1-day observed food intake in 30 women with AN and 28 control subjects. RESULTS: Reported intake by diet history was similar to observed intake for macronutrient composition and fat intake for patients with AN. Reported energy intake was higher than observed intake (1,602 +/- 200 kcal vs. 1,289 +/- 150 kcal, p <.05), but was in agreement with predicted energy expenditure by the Harris-Benedict equation (1,594 +/- 18 kcal, p =.97) in patients with AN. Micronutrient intake by diet history was highly correlated with observed intake in patients with AN. More than one half of the patients with AN failed to meet the recommended dietary allowance (RDA) for vitamin D, calcium, folate, vitamin B12, zinc, magnesium, and copper when assessed by diet history. In contrast to patients with AN, diet history did not correlate with observed intake of energy, macronutrients, or most micronutrients among the controls. DISCUSSION: Diet history is an accurate tool to assess fat intake and macronutrient composition in patients with AN and demonstrates significant micronutrient deficiencies in this population. The agreement between total energy intake and predicted energy expenditure supports the overall utility of the diet history in the nutritional assessment of patients with AN.