Radiophysical characteristics of different detectors for use in dosimetry

The present study investigated the radiophysical influences on the measurement of dosimetry basic data, attributable to field size, photon energy and detector type. A natural diamond detector, two ionisation chambers, different Si-diodes and a EBT-Gafchromic film were studied for this purpose. The characteristics of the detectors were investigated with regard to the measurement of output factors, lateral beam profiles and relative depth-dose curves for narrow and wide photon beams of 15 MV Significant differences in output factors were obtained with different detectors. For narrow fields, the natural diamond detector and the diodes PTW-60012 and SCX_WH-PFD measured output factors close to those of the EBT-Gafchromic film. The output facto rfor large fields was overestimated by the unshielded diode PTW 60012 and the PinPoint-chamber PTW-31006 because of their over-response to scattered photons. The relative depth dose distributions for wide beams at large depths agree well for the diamond, the ionisation chambers and the shielded Diode SCX_ WH-PFD and PTW-60008, while the measured dose was overestimated by an unshielded diode PTW-60012. Considering the influence due to the sensitive materials and the construction of the detectors the manufacturers of dosimeters have specified the application ranges for the various types of detectors.     

Biomechanical analyses of overlap and mesh dislocation in an incisional hernia model in vitro

BACKGROUND: Incisional hernia repair is one of the most common surgical complications. Despite the introduction of mesh techniques of repair, recurrences are still prevalent. The aim of the current study was to evaluate the dependence of mesh dislocation on defect size, facial overlap, mesh-position, and orientation of the mesh in cases of anisotropic stretchability. METHODS: An in vitro incisional hernia model was used, which consisted of a pressure chamber, an elastic silicone pad representing the peritoneal sac, and a silicone mat with bovine muscle tissue representing the abdominal wall. Intrinsic pressure (up to 200 mm Hg) was generated within the pressure chamber by continuous inflation with CO(2). A slit-like or flap-like defect was created in the silicone mat to simulate small or large hernia defects, respectively. The implanted mesh was arranged in both onlay and sublay configurations. A large pore polypropylene mesh with significant anisotropic stretchability was investigated, whereas overlaps of 2, 3, and 4 cm were applied. RESULTS: Despite the application of pressures up to 200 mm Hg, no mesh ruptures occurred. In the slit-like defect model, the minimal overlap required to prevent dislocation at 200 mm Hg was 3 cm using the sublay technique provided that the mesh was positioned with its most stretchable axis parallel to the largest slit dehiscence. Perpendicular rotation of the mesh resulted in dislocation at 160 mm Hg, despite using an overlap of 3 cm. Mesh reinforcement showed less stability in both the onlay position and the flap-like defect. CONCLUSION: An overlap of 3 cm is sufficient to prevent early mesh dislocation. Meshes with anisotropic stretchability should be orientated with the most stretchable axis in the direction of least overlap.     

Affektionen der Lendenwirbelsäule bei rheumatoider Arthritis

In rheumatoid arthritis the anatomical structures of the lumbar spine are affected by the same mechanisms of destruction as are known from other skeletal regions. Although spinal symptoms do not become apparent until the later stages of rheumatoid arthritis, patients do sometimes complain of typical symptoms. We present data recorded in 19 patients with seropositive rheumatoid arthritis who underwent hospital treatment directed exclusively at isolated low-back pain. The patients were questioned in some detail with the aid of instruments including the Oswestry, TypE, HAQ and RADAI questionnaires and a visual-analogue-pain scale. Roentgen exposures were also evaluated. A comparison was drawn between patients treated surgically with decompression and various spondylodeses (n=13) and those who received conservative treatment (n=6). Better results were obtained in the group of patients treated surgically, though a statistical evaluation was not possible. No histological evidence of rheumatoid alterations was found in the intervertebral disc tissue samples available.     

Involvement of dopamine D<Subscript>1</Subscript> and D<Subscript>2</Subscript> receptors in the nucleus accumbens core and shell in inhibitory response control

Rationale Impaired inhibitory control over behavior is a key feature in various psychiatric disorders, and recent studies indicated an important role for dopamine D₁ and D₂ receptors and the nucleus accumbens (Acb) in this respect. Objective The present experiments were designed to study the role of dopamine D₁ and D₂ receptors in the Acb in inhibitory response control. Methods Rats were trained in a five-choice serial reaction time task and received bilateral infusions into the Acb core or shell of either SCH 23390 or eticlopride (representing selective dopamine D₁ and D₂ receptor antagonists, respectively). Subsequently, the effects of systemic amphetamine on inhibitory response control were examined. Results Eticlopride into either the Acb core or shell did not affect premature responding, a measure for inhibitory response control, but increased reaction time and errors of omission. In contrast, SCH 23390 into both regions reduced premature responding, slightly improved attentional performance in the core and increased errors of omission in the shell. Amphetamine robustly increased premature responding which was dose-dependently blocked by eticlopride in the Acb core and attenuated by eticlopride in the shell. In addition, amphetamine slightly decreased accuracy and reaction time, and these effects were inhibited by eticlopride in both regions. SCH 23390 infusion into the Acb core or shell did not alter amphetamine’s effects. Conclusion Our data provide evidence for the involvement of dopamine D₁ and D₂ receptors in the Acb core and shell in inhibitory response control and attentional performance.     

Marijuana use motives: A confirmatory test and evaluation among young adult marijuana users

The present investigation evaluated the measurement model and construct validity of marijuana use motives as measured by the Marijuana Motives Measure (MMM; [Simons, J., Correia, C. J., Carey, K. B., and Borsari, B. E. (1998). Validating a five-factor marijuana motives measure: Relations with use, problems, and alcohol motives. Journal of Counseling Psychology, 45, 265-273]). Confirmatory factor analysis (CFA) and incremental tests of validity of marijuana use motives were conducted on a sample of young adult marijuana users (n=227, 127 women; M(age)=20.11, SD=4.30 years). As hypothesized, CFA analysis of marijuana use motives, as indexed by the MMM, demonstrated support for a multidimensional measurement model; specifically, a five-factor solution denoting Enhancement, Conformity, Expansion, Coping, and Social motives for marijuana use, each with satisfactory levels of internal consistency. Subsequent tests of incremental validity suggested that only certain motives were uniquely related to current substance use and cognitive-affective factors. Results are discussed in relation to refining the scientific understanding of marijuana use motives.     

Incremental validity of anxiety sensitivity in relation to marijuana withdrawal symptoms

The present investigation examined the relation between anxiety sensitivity (AS) and marijuana withdrawal severity among 84 (47 female) young adult marijuana smokers. As expected, after covarying for the theoretically-relevant variables of frequency of past 30-day marijuana use, number of cigarettes smoked per day, volume of alcohol consumed, and anxious arousal as well as anhedonic depressive symptoms, both the global AS factor and the AS-mental incapacitation concerns factor were significantly related to the severity of retrospectively reported marijuana withdrawal symptoms. Results are discussed in relation to better understanding cognitive-emotional variables related to the marijuana withdrawal.     

Hyposensitization therapy with autologous semen in two Dutch caucasian males: beneficial effects in Postorgasmic Illness Syndrome (POIS; Part 2)

IntroductionPostorgasmic illness syndrome (POIS) is a post‐ejaculatory complex of local and/or systemic symptoms that nearly always occurs within seconds, minutes, or hours post‐masturbation, coitus, or spontaneous ejaculation. Recent data suggest an autoimmunogenic/allergic underlying mechanism.AimTo treat males with POIS by hyposensitization with their own semen (autologous semen).MethodsTwo males suffering from POIS, of which one male with coincidental lifelong premature ejaculation (PE) were investigated. Based on their local and systemic symptoms including a positive dermatologic reaction after skin‐prick testing with autologous semen, auto‐allergy to semen was likely an underlying mechanism. A hyposensitization program was initiated, including multiple subcutaneous (SC) injections with autologous semen, initially at 2 weeks intervals in the first year and gradually at 4 weeks intervals in the second and third year. From initial semen dilutions of 1 on 40,000 and 1 on 20,000, the titers were gradually increased to 1 on 20 and 1 to 280, respectively.Main Outcome MeasuresEvaluation with a dedicated questionnaire about severity of POIS symptoms and specialized interviews on self‐perceived intravaginal ejaculation latency times (IELT) before and during the desensitization program.ResultsPOIS was confirmed in both subjects, PE was confirmed in one male, and skin‐prick tests with autologous semen in both subjects were positive. During the program, gradual reduction of complaints resulted in 60% and 90% amelioration of POIS complaints at 31 and 15 months, respectively, which coincided in one male with a delay of the IELT from 20 seconds at baseline to 10 minutes after 3 years of treatment. The cause of this association with IELT is unknown and remains to be elucidated.ConclusionsTwo males with POIS were successfully treated by hyposensitization with autologous semen, which supports an immunogenic/allergic etiology and underscores the clinical implication for immunological sexual medicine. Waldinger MD, Meinardi MMHM, and Schweitzer DH. Hyposensitization therapy with autologous semen in two Dutch Caucasian males: Beneficial effects in postorgasmic illness syndrome (POIS) (Part 2). J Sex Med 2011;8:1171–1176.     

Chronic paroxetine treatment does not affect sexual behavior in hormonally sub-primed female rats despite 5-HT₁(A) receptor desensitization

IntroductionSelective serotonin reuptake inhibitors (SSRIs) cause sexual dysfunctions in humans. However, because SSRIs are used to treat depression, it is unclear whether the problems are caused by the drug, by the depression itself, or an interaction between both.AimThe present study investigated the effects of chronic paroxetine treatment on sexual behavior in female rats. Furthermore, we tested whether 5‐hydroxytryptamine (5‐HT)_1A receptors were desensitized in these females.MethodsOvariectomized female rats, either sub‐primed with estradiol or fully primed with estradiol and progesterone, were tested in a paced mating test. Proceptive (darting and hopping), receptive (lordosis), and paced mating‐related (percentages of exits and contact‐return latencies) behaviors were quantified during the course of 56 days of chronic paroxetine treatment (10 mg/kg and 20 mg/kg per day). The 5‐HT_1A/5‐HT₇ receptor agonist (±)‐8‐hydroxy‐2‐(dipropylamino)tetralin hydrobromide ((±)8‐OH‐DPAT) alone and in combination with the selective 5‐HT_1A receptor antagonist WAY‐100635 was administered to study putative 5‐HT_1A desensitization in the same females.Main Outcome MeasuresProceptive, receptive, and paced mating behaviors were quantified.ResultsAcute and chronic paroxetine treatment did not change proceptive and receptive behaviors in both sub‐primed and fully primed female rats. In all groups, (±)8‐OH‐DPAT showed a clear dose‐dependent inhibition of sexual behaviors in vehicle‐treated females and a right‐shifted dose–response effect in the paroxetine‐treated rats. WAY‐100635 attenuated the inhibiting effect of the 5‐HT_1A receptor agonist in all females. These data suggest 5‐HT_1A receptor desensitization after chronic paroxetine treatment.ConclusionsChronic paroxetine treatment does not cause sexual side effects in sub‐ or fully hormonally primed female rats. Furthermore, chronic treatment causes adaptive changes in the serotonin system such as desensitization of 5‐HT_1A receptors, which may counteract the inhibiting effects of increased extracellular serotonin levels in the chronic paroxetine‐treated rats. Snoeren EMS, Refsgaard LK, Waldinger MD, Olivier B, and Oosting RS. Chronic paroxetine treatment does not affect sexual behavior in hormonally sub‐primed female rats despite 5‐HT_1A receptor desensitization.