Precision of the Hologic Horizon A dual energy X-ray absorptiometry in the assessment of body composition.

BACKGROUND: As the number of individuals with obesity increases, so too will the demand for a precise, cost-effective and safe method to better risk-stratify this heterogenous population. Visceral adipose tissue (VAT) area, a body composition measurement has been associated with the many facets of the metabolic syndrome. AIM: To determine the precision of dual energy X-ray absorptiometry (DXA) in providing body composition measurements, including VAT area, using the Hologic Horizon A scanner. METHOD: Thirty participants (mean age 64 years, 47% male), underwent two sequential body composition scans. The coefficient of variation (CV) and least significant change (LSC) were calculated for android/gynoid ratio, appendicular lean/height2, lean/height2, total body fat and lean mass, total body mass, and subcutaneous adipose tissue (SAT) and VAT area. Participants were stratified according to age (<70 or ≥70 years), body mass index (BMI) (≤30 kg/m2 or >30 kg/m2) and sex (male or female). The CV was calculated for each parameter and then analysed for differences between groups. RESULTS: The CV for all parameters was <3% with the exception of SAT (3.86%). The CV of VAT area was 2.63% with a LSC at 95% confidence of 7.28%. Apart from the CV differences between males and females for android/gynoid ratio (male: 3.56% vs. female: 1.74%, p = 0.01) and SAT area (5.04% vs. 2.46%, p = 0.01), there were no significant differences identified between the calculated CV for all other body composition parameters when participants were stratified by age, BMI and sex. CONCLUSION: DXA scanning, using the Hologic Horizon A system, is capable of providing precise body composition measurements.

Bone health in women with breast cancer.

Women with early, estrogen receptor-positive breast cancer are treated with adjuvant endocrine therapy, using aromatase inhibitors or selective estradiol receptor modulators such as tamoxifen, to deprive breast tissue from the deleterious effects of estradiol action, hence improving long-term prognosis. Aromatase inhibitors and, in premenopausal women, tamoxifen accelerate bone loss and increase fracture risk. Therefore, all women commencing endocrine therapy need a targeted work-up to assess the baseline fracture risk, and monitoring of bone health during endocrine therapy should be individualized based on this baseline risk. While high-level evidence specific to early breast cancer is lacking, non-pharmacologic measures to maintain optimal bone health such as weight-bearing exercise and calcium and vitamin D sufficiency should be implemented in all women. Antiresorptive treatment should be initiated in all women with preexisting fragility fractures (including vertebral morphometric fractures) and should be considered in women with areal bone mineral density (BMD) T-scores < -2.0 (or Z-scores in women aged <50 years) or those experiencing rapid bone loss (≥5% per year), taking into consideration the baseline BMD and other risk factors for fracture. Further clinical trial evidence is required to provide definitive guidance regarding criteria to initiate antiresorptive treatment, choice of agents, and duration of treatment, taking into account potential oncologic benefits of antiresorptive therapy on breast cancer-related outcomes.

Pitfalls in bone density monitoring in prostate cancer during anti-resorptive treatment.

A 74-year-old man presented to the Andrology Clinic for management of potential complications of androgen deprivation therapy for prostate cancer. He had a rising prostate-specific antigen with a concurrent rise in alkaline phosphatase and bone remodeling markers. This was despite treatment with a radical prostatectomy, androgen deprivation, and anti-resorptive therapy. A follow-up dual-energy X-ray absorptiometry scan revealed a marked increase in his bone mineral density at both the lumbar spine and femoral neck. This increase, especially in the context of rising bone remodeling markers, was unlikely due to the effect of anti-resorptive therapy alone. Subsequent whole-body bone scintigraphy demonstrated a "superscan" phenomenon which is characterized by uniform and avid tracer retention throughout the skeleton, in this case due to widespread skeletal metastasis, so that the usual physiological uptake in the kidneys is no longer observed and can be misinterpreted as a "normal" scan if the absence of the kidneys is not recognized. This case highlights the importance of considering diffuse metastatic disease when there is a rapid increase in bone mineral density, even in individuals treated with anti-resorptive therapy.

Current technique of laparoscopic total mesorectal excision (TME): an international questionnaire among 368 surgeons.

BACKGROUND: Current literature shows no consensus for the technique of laparoscopic total mesorectal excision (LTME). This study aimed to assess the current practice of LTME. METHODS: From January to March 2008, members of the European Association for Endoscopic Surgery (EAES), the Indian Association of Gastrointestinal Endo-Surgeons (IAGES), and the Society of Laparoscopic Surgeons (SLS), together with renowned surgeons in the field of LTME, were invited to fill out an online questionnaire concerning aspects of LTME. RESULTS: The 368 questionnaires showed that 77% of the study participants performed 1-20 LTMEs per year (low volume) and that 33% performed more than 20 LTMEs per year (high volume). Preoperative bowel preparation (PBP), Trendelenburg position, periumbilical insertion of a 30º laparoscope, medial-to-lateral dissection, ultrasonic hemostasis, high-tie ligation, splenic flexure mobilization, left ureteral identification, partial sigmoid resection, extraction of the specimen by a new minilaparotomy and wound protector, end-to-end stapled anastomosis using a 28- to 29-mm anvil with 3.5-mm staples, abdominal lavage, pelvic drainage, and diverting ileostoma were performed by a majority of the surgeons. Less consistency was observed in identification of the right ureter, dissection of Denonvilliers' fascia, location of the minilaparotomy, and construction of a colonic pouch. There were significant differences between high and low volume and between American and European surgeons. Significantly more low-volume surgeons indicated a preference for an open TME depending on the age and gender of the patient, the presence of comorbidity, previous laparotomy, and locally advanced tumor. More low-volume surgeons applied PBP (83.4% vs. 71.8%; p = 0.017). On the average, high-volume surgeons identified more autonomic pelvic nerves during dissection (2.6 vs. 1.8 nerves). The right ureter was identified by 66% of the American and 31.2% of the European surgeons. In the United States 91.5% and in Europe 61.2% created an end-to-end anastomosis. Pouches were created by 32% of the European and 6.8% of the American surgeons. CONCLUSION: The respondents showed an apparent preference for several aspects of LTME. Differences were related to expertise and still more to continent.

Iliopsoas bursitis following total hip replacement.

We report the imaging features of a 52-year-old man presenting with a groin mass and gross lower limb oedema secondary to venous occlusion by massive cystic enlargement of the iliopsoas bursa 4 years after uncemented primary total hip replacement. Ultrasonography of the groin mass demonstrated a large cystic lesion extending into the pelvis. CT showed displacement of the external iliac vessels with venous compression. Bursography showed the bursa's margins and no communication with the hip joint. Diagnostic aspiration excluded infection, but fluid recollection occurred subsequently. Complete resolution of symptoms, including limb swelling, followed surgical excision with no recurrence at the 5-year follow-up. We believe iliopsoas bursitis occurred as a tissue response to polyethylene wear within the prosthetic hip and occurred even in the absence of loosening or a direct communication between bursa and joint.

Levels-of-processing effects on Chinese character completion: the importance of lexical processing and test cue.

The levels of processing (LoP) effect was studied in Chinese character completion tasks. The same stem cue, either graphemically or semantically related to the target character, was used to generate either a perceptual or a conceptual test. Participants received either direct or indirect instructions, so that the same stem cue also produced either an explicit or an implicit test of memory. This allowed us to examine simultaneously the roles of perceptual versus conceptual test and retrieval intentionality in the LoP effect. No LoP effects were found when the memory test was implicit. LoP effects were also not found for stems and characters related graphemically (perceptually), but were found for stems and characters related semantically (conceptually) when the memory test was explicit. The results are discussed in terms of the importance of lexical processing for character completion tests and the importance of reinstatement of the study process during retrieval for explicit memory tests.

Rival Penalized Competitive Learning based approach for discrete-valued source separation.

This paper presents an approach based on Rival Penalized Competitive Learning (RPCL) rules for discrete-valued source separation. In this approach, we first build a connection between the source number and the cluster number of observations. Then, we use the RPCL rule to automatically find out the correct number of clusters such that the source number is determined. Moreover, we tune the de-mixing matrix based on the cluster centers instead of the observation themselves, whereby the noise interference is considerably reduced. The experiments have shown that this new approach not only quickly and automatically determines the number of sources, but also is insensitive to the noise in performing blind source separation.

Adaptive rival penalized competitive learning and combined linear predictor model for financial forecast and investment.

We propose a prediction model called Rival Penalized Competitive Learning (RPCL) and Combined Linear Predictor method (CLP), which involves a set of local linear predictors such that a prediction is made by the combination of some activated predictors through a gating network (Xu et al., 1994). Furthermore, we present its improved variant named Adaptive RPCL-CLP that includes an adaptive learning mechanism as well as a data pre-and-post processing scheme. We compare them with some existing models by demonstrating their performance on two real-world financial time series--a China stock price and an exchange-rate series of US Dollar (USD) versus Deutschmark (DEM). Experiments have shown that Adaptive RPCL-CLP not only outperforms the other approaches with the smallest prediction error and training costs, but also brings in considerable high profits in the trading simulation of foreign exchange market.

Differences in FM response correlate with morphology of neurons in the rat inferior colliculus.

The response characteristics to linear frequency sweeps were studied in two groups of FM (frequency modulation) sensitive neurons in the rat inferior colliculus. 'FM specialized' cells responded to frequency sweeps but not to pure tones. 'Mixed' cells responded to both frequency sweeps and pure tones. FM specialized cells preferred faster and broader sweeps of higher intensity than did mixed cells and were more directionally selective. In addition, FM specialized cells were more sharply tuned to FM velocity and FM range and had longer response latencies. Physiologically identified FM cells stained intracellularly with horseradish peroxidase revealed differences in morphology correlating with the differences in their responses to tones. FM specialized cells had larger dendritic fields, more dendritic branching and more dendritic spines than did mixed cells. The findings are taken as evidence that the two groups of inferior colliculus neurons are both functionally and morphologically distinct.

Response of medullary reticular neurons of cat to off-vertical axis rotations.

To investigate whether neurons in the medullary reticular formation of decerebrate cats can encode spatial orientation during 360 degrees off-vertical axis rotations (OVAR), responses of these units were studied during constant velocity OVAR in clockwise (CW) and counter-clockwise (CCW) directions. Tilt-sensitive units, some of which were activated by antidromic stimulation of the thoracic cord, were found to respond to 360 degrees OVAR with position-and direction-dependent modulation in discharge rates. For the individual responsive unit there was a difference in the spatial location of the CW and CCW discharge maxima, while a comparable response gain was obtained for rotations in either direction. The orientation of the best response of each unit was not significantly modified by changes in the amplitude of head tilt and/or velocity of rotation. Such characterized directional axes of the medullary reticular units were found to have a fairly equal distribution over the 360 degrees. The role that neurons in the medullary reticular formation plays in encoding otolith inputs with respect to head movements is discussed.

Rhythmic release pattern of pineal melatonin in rodents.

The plasma melatonin in the confluens sinuum of anesthetized rabbits and rats exhibited an episodic release pattern, with pulses superimposed on a basal level. The rhythmicity of pineal melatonin release revealed by our experimental paradigm was dependent on the blood sampling interval. In rabbits, it was found that the plasma melatonin level in the confluens sinuum was 7-15 times higher than that obtained from the plasma collected at the same time from the peripheral artery where the melatonin level also showed a pulsatile pattern. Diurnal variation in pineal melatonin level in the confluens sinuum was observed only in acutely blinded rabbits and rats. Electrical stimulation of the unilateral cervical sympathetic trunk of rabbits resulted in elevation of the level of plasma melatonin in the confluens sinuum, while the frequency of pulse peaks of plasma melatonin revealed at 4-min intervals was not affected. Similar results were obtained in rabbits with systemic administration of beta-adrenergic agents. These findings suggest that the release of pineal melatonin into the confluens sinuum is under the regulation of the cervical sympathetic system. The sympathetic influence on pineal melatonin secretion seems to vary with age. Furthermore, age-related fluctuation of systemic blood melatonin appeared to be the results of changes in the rate of pineal melatonin secretion, body growth and ageing.

Simultaneous determination of some active ingredients in cough-cold syrups by gas-liquid chromatography.

A simple, efficient and accurate gas-liquid chromatography (GLC) method for the simultaneous determination of eight active ingredients in cough-cold syrups has been developed. The active ingredients under study were bromhexine, chlorpheniramine, codeine, dextromethorphan, diphenhydramine, ephedrine/pseudoephedrine, guaiphenesin and papaverine. Before injection, the active ingredients were first separated, from the excipients present in the cough-cold syrups, with chloroform, from alkaline medium. They were then separated by GLC on a glass column (5 ft x 2 mm i.d.) packed with 3% of OV-25 supported on Supelcoport (80-100 mesh). The column temperature was maintained at 170 degrees C for 1 min, then programmed to 265 degrees C at a rate of 10 degrees C min-1, and maintained at this temperature for 10 and 1 min, respectively, for samples with and without papaverine. The flow-rate of the nitrogen carrier gas was 30 ml min-1. A flame-ionisation detector was used for detection, and clomipramine hydrochloride was used as the internal standard. The recoveries of the drugs ranged from 96.0 to 99.7%, and the relative standard deviations for ten replicate determinations ranged from 0.49 to 4.7%. Results are reported for nine commercially available cough-cold syrups.

Patterns of pineal melatonin secretion in rabbits: diurnal variation of basal and pulsatile release.

The level and release pattern of plasma melatonin in the confluens sinuum of 28 sighted and 18 blinded (i.e. acute bilateral orbital enucleation) rabbits anesthetized with pentobarbital were studied. The animals had been adapted to a 12:12 h light-dark regime. Blood samples were collected from the cannulated confluens sinuum and/or the femoral artery at either 2- or 4-min intervals in both the light and dark phases. Plasma melatonin was determined by radioimmunoassay. In all rabbits studied, plasma melatonin in the confluens sinuum exhibited an episodic release pattern, with pulses superimposed on a basal level. At 4-min sampling intervals, the pulsatile release of melatonin in sighted rabbits were 3.8 peaks/h in the light phase; shorter sampling interval (2-min) revealed more frequent pulsatile release of melatonin (5.1 peaks/h). In sighted animals in the light phase, the level of melatonin in the plasma of confluens sinuum was 7-15 times higher than that obtained from the plasma collected at the same time from the peripheral artery where the level of melatonin also exhibited pulsatile pattern. In blinded animals, melatonin levels in terms of mean concentration, mean maximum level and mean minimum (or baseline) level obtained in the dark phase were 12-14 times higher than those obtained in the light phase. These results suggest that the level of melatonin exhibits a diurnal rhythm in the confluens sinuum of rabbits.

Elevation of pineal melatonin secretion by electrical stimulation of the cervical sympathetic trunk in rabbits.

The influence of electrical stimulation of the unilateral sympathetic trunk on the release patterns of plasma melatonin in the confluens sinuum of anesthetized rabbits was studied. Plasma melatonin exhibited an episodic release pattern, with pulses superimposed on a basal level. The mean concentration, mean maximum and minimum levels of plasma melatonin in the confluens sinuum were found to be significantly elevated when the sympathetic trunk was electrically stimulated. The frequency of pulse peaks of plasma melatonin sampled at 4-min intervals was not affected by electrical stimulation. Our results suggest that the diurnal rhythmic secretory pattern of pineal melatonin into the confluens sinuum of rabbits is regulated by the cervical sympathetic system.

Light diffraction intensity from muscle fibres in different osmotic solutions: measurement of equilibration time.

A new method for evaluating the osmotic equilibration time of striated muscle fibres is described. Single fibres from the semitendinosus muscles of frog were illuminated normally with a He-Ne laser. The first-order diffraction intensity was measured continuously after the tonicity of the fibre's bathing solution was changed abruptly. Hypertonicity decreased while hypotonicity increased the intensity. The time course of the intensity decrease or increase followed closely a simple exponential with a single time constant. It is proposed that the time constant associated with the diffraction intensity transient is a true representation of the equilibration process. A simple diffraction model provides a relationship between diffraction intensity and the diameter of the muscle fibre. This relationship is used to explain the diffraction intensity of fibres in different osmotic solutions.

Simultaneous determination of ascorbic acid, caffeine and paracetamol in drug formulations by differential-pulse voltammetry using a glassy carbon electrode.

A simple, rapid and accurate method for the simultaneous determination of ascorbic acid, caffeine and paracetamol in drug formulations has been developed. Peak currents were measured with a glassy carbon electrode at +0.350, +0.618 and +1.425 V versus a saturated calomel electrode for ascorbic acid, paracetamol and caffeine, respectively. Perchloric acid (0.1 M) - methanol (1 + 1) was used both as a solvent and supporting electrolyte. The optimum modulation amplitude, pulse repeat time and scan rate of the polarographic analyser were found to be 50 mV, 0.5 s and 5 mV s-1, respectively and the linear calibration ranges for ascorbic acid, caffeine and paracetamol were 0-35, 0-50, and 0-55 micrograms ml-1, respectively. The relative standard deviations for 9.30 micrograms ml-1 of ascorbic acid, 8.50 micrograms ml-1 of caffeine and 7.30 micrograms ml-1 of paracetamol were 1.3, 2.5 and 0.7%, respectively. Results are reported for several commercially available drugs.

The origin and terminal arbors of individual uncrossed retinogeniculate fibers in rabbits.

The distribution and morphology of individual uncrossed retinogeniculate fibers in both normal and monocularly enucleated adult Dutch-belted rabbits were studied using horseradish peroxidase and wheat germ agglutinin conjugated to horseradish peroxidase as neuronal markers. The results showed that the uncrossed retinogeniculate fibers were distributed almost entirely in the ipsilateral segment of the dorsal nucleus of the lateral geniculate body, and the extent of terminal distribution of the fibers observed in rabbits with one eye enucleated during the young adult stage was essentially the same as that in the normal rabbit. Most of the uncrossed retinogeniculate fibers appeared to arise as collateral branches of optic tract fibers which were apparently destined for the pretectum or the superior colliculus. The uncrossed retinogeniculate fibers labeled by the wheat germ agglutinin conjugated to horseradish peroxidase passed through the dorsal nucleus of the lateral geniculate body without any branching until they reached the ipsilateral segment. There they could be divided into several morphological types although the possibility that they may represent different classes of a continuum cannot be ruled out.