Effect of nordihydroguaiaretic acid on luteal phase length and oxytocin-induced release of prostaglandin F2 alpha in heifers

Two experiments were conducted to determine if intrauterine infusion of nordihydroguaiaretic acid, a lipoxygenase pathway inhibitor, would delay luteolysis (Experiment 1) and inhibit oxytocin-induced release of prostaglandin F2 alpha (as measured by the stable prostaglandin F2 alpha metabolite, 15-keto-13,14-dihydroprostaglandin F2 alpha) in plasma on d 16 (d 0 = estrus) of the estrous cycle (Experiment 2). Nordihydroguaiaretic acid (20 mg) or saline was infused twice daily into the uterus on d 14 to 23 (Experiment 1) or d 14 to 20 (Experiment 2) postestrus, respectively. In Experiment 1 and 2, mean concentration of progesterone was higher and luteolysis was delayed in nordihydroguaiaretic acid-infused heifers compared with saline-infused heifers. In Experiment 2, saline or oxytocin (100 IU, i.v.) was injected into each heifer on d 16 postestrus to stimulate the release of prostaglandin F2 alpha from the uterus. Mean concentration of 15-keto-13,14-dihydroprostaglandin F2 alpha increased within 1.5 h postinjection in heifers infused with saline, whereas concentration of 15-keto-13,14-dihydroprostaglandin F2 alpha in nordihydroguaiaretic acid-infused heifers did not increase within the same time period. Thus, nordihydroguaiaretic acid may inhibit both the lipoxygenase and cyclooxygenase pathways of arachidonic acid metabolism and therefore delay luteolysis.     

A paradigm of experimentally induced mild hyperthyroidism: effects on nitrogen balance, body composition, and energy expenditure in healthy young men

OBJECTIVE: To conceptualize, with fine needle aspiration cytology (FNAC), the early cellular events occurring in and around fresh autogenous and allogenic bone grafts during the first 40 postimplantation days. STUDY DESIGN: Forty-eight cases of bone grafts were studied by FNAC at serial intervals of 10, 20, 30 and 40 postimplantation days. Twenty patients were recipients of autogenous grafts, 16 received 0.6N HCI partially decalcified allogenic bone implants, and 4 received combined autogenous and allogenic bone grafts (included in the allograft group). There were eight control cases of closed fracture shaft femur, which were managed conservatively. RESULTS: The initial cellular responses in autogenous grafts, allografts and controls appear to be a part of the nonspecific reparative process followed by a more specific phase, with a steady increase in relative lymphocyte count from the 20th day onwards. Osteogenesis, as judged by osteoblasts and osteoclasts, was also comparable. CONCLUSION: Partially decalcified allografts appear to be a good substitute for autogenous bone grafts in clinical practice when adequate autogenous material is not available. FNAC is a good technique for studying bone graft responses without interfering with graft uptake. It is helpful in the early detection of subclinical infection or any other pathology at the graft site.     

Psychology interns as patient suicide survivors: Incidence, impact, and recovery.

The authors investigated incidence, impact, and methods of coping with patient suicide during the training years of psychology graduate students. All 54 interns in clinical psychology at the Boston VA in 1983–1988 were surveyed. One in 6 Ss had experienced a patient's suicide at some time during their training. The group who experienced a patient's suicide and a group who experienced a patient's suicide attempt both reported high levels of stress on the Impact of Event Scale. Trainees with patient suicides reported stress levels equivalent to that found in patient samples with bereavement and higher than that found with professional clinicians who had patient suicides. Trainees most frequently turned to supervisors for both support and formulation of the suicide. Preparatory efforts at suicide education were found to be minimal and inadequate. Recommendations for assisting the trainee who experiences a patient's suicide are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Demonstration of a word design strategy for DNA computing on surfaces

A strategy for DNA computing on surfaces using linked sets of 'DNA words' that are short oligonucleotides (16mers) is proposed. The 16mer words have the format 5'-FFFFvvvvvvvvFFFF-3' in which 4-8 bits of data are stored in 8 variable ('v') base locations, and the remaining fixed ('F') base locations are used as a word label. Using a template and map strategy, a set of 108 8mers each of which possesses at least a 4 base mismatch with the complements to all the other members of the set (4bm complements) are identified for use as a variable base sequence set. In addition, sets of 4 and 12 word labels of the form ABCD....DCBA that are respectively 8bm and 6bm complements with each other are identified. The 16mers are chosen to have a G/C content of 50% in order to make the thermodynamic stability of the perfectly matched hybridized DNA duplexes similar; a simple pairwise additive method is used to estimate the perfect match and mismatch hybridization thermodynamics. A series of preliminary experiments are presented that use small arrays of 16mers attached to chemically modified gold surfaces and fluorescently labeled complements to study the hybridization adsorption and enzymatic manipulation of the oligonucleotides.     

CONCENTRATION OF FELDSPATHIC WASTE FROM A TITANIUM MINE NEAR ROSELAND,VIRGINIA *

The beneficiation of the feldspathic waste from a titanium mine near Roseland, Virginia, is discussed. This waste, which is mainly sodic plagioclase, quartz, and an iron-bearing mineral, gedrite, contains about 5.3% of Fe₂O₃. By magnetic concentration, 73% of the feed was recovered in a feldspar-quartz mixture with an iron content of 0.81% of Fe₂O₃. From this nonmagnetic product, between 85% and 90% of the feldspar with an iron content of 0.41 to 0.52% of Fe₂O₃ was recovered by agglomerate tabling and flotation. Examination of the feldspar concentrate, however, showed that iron stains and iron-bearing impurities of microscopic size in the feldspar prevented the separation of a feldspar concentrate with less than 0.36% of Fe₂O₃.     

ABCD matrices for dispersive pulse propagation

The use of the ABCD matrices for the calculation of pulse propagation in second-order dispersive media is developed rigorously. Their usefulness is demonstrated by obtaining the results for the propagation of a Gaussian pulse with an arbitrary linear chirp. By analogy with ray optics, the concept of a time ray is introduced to give further insight. The analogy with paraxial optics is carried further by extending the matrix method to a complete Hermite-Gaussian basis and thus to arbitrarily shaped and nonlinearly chirped pulses. Some practical applications of the matrix method are discussed     

In vitro binding of bile acids by bananas,peaches, pineapple,grapes, pears,apricots and nectarines

The in vitro binding of bile acids by bananas (Musa × paradisiaca), peaches (Prunus persica), pineapple (Ananus comosus), grapes (Vitis spp.), pears (Pyrus communis), apricots (Prunus armeniaca) and nectarines (Prunus persica, nectarina) was determined using a mixture of bile acids secreted in human bile at a duodenal physiological pH of 6.3. Six treatments and two blank incubations were conducted, testing various fresh fruits on an equal dry matter basis. Considering cholestyramine (bile acid binding, cholesterol lowering drug) as 100% bound, the relative in vitro bile acid binding percentages on dry matter (DM), total dietary fibre and total polysaccharides basis were 2–9%, 15–101% and 10–101%, respectively. Bile acid binding, on a DM basis, for bananas was significantly (P ? 0.05) higher and that for nectarines significantly lower than those for peaches, pineapple, grapes, pears and apricots. The bile acid bindings for peaches and pineapple were similar and significantly higher than those for grapes, pears and apricots. Binding values for grapes and pears were significantly higher than apricots. These results point to the relative health promoting potential of bananas > peaches = pineapple > grapes = pears > apricots > nectarines, as indicated by their bile acid binding on a DM basis. The variability in bile acid binding between the fruits tested maybe related to their phytonutrients, antioxidants, polyphenols, flavonoids (anthocyanins, flavonols, and proanthocyanidins), structure, hydrophobicity of undigested fractions, anionic or cationic nature of the metabolites produced during digestion or their interaction with active binding sites. Animal studies are planned to validate in vitro bile acid binding of fruits, observed herein, to their healthful potential, atherosclerosis amelioration and cancer prevention.     

Nonclinical model for assessing gastric effects of bisphosphonates

Mechanisms by which ketones potentiate manganese-bilirubin (Mn-BR)-induced cholestasis are unknown. The purpose of the present study was to investigate the effect of methyl isobutyl ketone (MiBK), a widely used ketonic solvent, at the level of the bile canalicular membrane (BCM) and to verify if altered membrane lipid dynamics could be involved in MiBK-potentiated Mn-BR cholestasis. Male Sprague-Dawley rats were exposed 4 hr/day for 3 days to MiBK vapors (200 or 600 ppm). Eighteen hours after the last exposure, manganese (Mn, 4.5 mg/kg) was given i.v. followed 15 min later by bilirubin (BR, 25 mg/kg). Rats were killed 30 min after BR; liver cell plasma membranes (bile canalicular and sinusoidal), microsomes, mitochondria, and cytosol were isolated by differential centrifugation. Lipids were extracted and cholesterol was measured in each fraction. After Mn-BR and MiBK exposure (600 ppm), results indicated a marked increase in BCM cholesterol content compared to rats exposed to air only. This increase was greater than that due to Mn-BR or MiBK given alone. Also, results indicated that cholesterol increased in a dose-related fashion in BCM after MiBK exposure, whereas PM cholesterol remained unaltered. To identify the source of the increased BCM cholesterol and to permit distinction between de novo cholesterol synthesis and subcellular shifts, the hepatic lipid pool was labeled in vivo with [3H]-cholesterol and [2-14C]-mevalonic acid, a cholesterol synthesis precursor. Results showed that after 600 ppm MiBK exposure, 14C-labeled cholesterol was greater than 3H-labeled cholesterol, indicating that the contribution of de novo cholesterol synthesis to the total cholesterol content of the various isolated hepatocellular fractions was more important than the contribution of intracellular pools. Therefore, increased BCM cholesterol content and enhanced accumulation of newly synthesized cholesterol appear to be involved in MiBK potentiation of Mn-BR-induced cholestasis.     

Science of daylighting in buildings

The materials characterisation requirements for accurate yet practical simulation of daylighting in buildings is examined for a range of emerging and existing technologies which seek to raise the contribution of daylighting to overall lighting requirements. Algorithms based on underlying physical models can be established from analysis of data on bi-directional transmission and reflection. Demonstrations of effects in simulation relevant to glare, view and illuminance are given.