Neurochemical correlates of sparing from motor deficits in rats depleted of striatal dopamine as weanlings

The behavioral and neurochemical effects of striatal DA depletions were investigated in rats lesioned as weanlings (Day 27) or as adults (250-300 g). Administration of 6-OHDA into the medial forebrain bundle resulted in comparably large (> or = 95%) depletions of tissue levels of DA in both age groups. As expected, rats depleted of DA as adults exhibited marked deficits in motoric behavior and body weight regulation that persisted for the 8 days of postsurgical observation. In contrast, rats depleted of DA as weanlings were spared from such deficits, and their behavior closely resembled that of age-matched controls. Microdialysis studies revealed dialysate levels of striatal DA that paralleled these age-dependent behavioral differences. At a time when age-related behavioral differences were still quite pronounced (5-6 days postsurgery), basal DA levels were reduced by 80% of control values in rats lesioned as adults whereas basal DA levels in rats lesioned as weanlings were unchanged relative to their controls. Finally, adults depleted of striatal DA as weanlings were no more sensitive to the movement-impairing effects of intrastriatal sulpiride (3.0 or 10.0 micrograms/hemisphere) infusions than were control rats. These data suggest that weanlings compensate for large, but incomplete, denervation of striatal DA with markedly enhanced release and turnover from residual terminals. This developmental plasticity may prevent the occurrence of behavioral deficits soon after the lesion and also the supersensitivity to the challenging effects of DA antagonists as animals grow into adulthood.     

Responses of sacral visceral afferents from the lower urinary tract,colon and anus to mechanical stimulation

The discharge characteristics of sacral visceral afferents supplying the urinary bladder, urethra, colon and anus to mechanical stimuli were analyzed in the anaesthetized cat. The stimuli used were passive distension (urinary bladder, colon), isovolumetric contraction (urinary bladder), movements of the urethral catheter and mechanical shearing stimuli (mucosal skin of the anal canal). (1) In total 245 afferent units which projected in the pelvic nerve were isolated from the sacral dorsal roots. From one of the following organs, urinary bladder, colon, urethra and anus 117 afferent units were activated. By these stimuli from the bladder, urethra and anus 122 afferent units could not be activated, and as far as tested also not from the colon; in 6 afferent units the classification was unclear. (2) Afferent units from the urinary bladder and the colon responded consistently to passive distension of the respective organ. The units from the urinary bladder showed graded responses at intraluminal pressures of about 10–70 mm Hg and responded also to isovolumetric contractions of the organ. The thresholds of the units from the bladder to passive distension and contraction varied from about 5 to 20 mm Hg intravesical pressure. (3) The afferent units from the urethra and the anus did not react or showed some weak phasic and irregular responses to distension and contraction applied to the urinary bladder or to distension of the colon. They were consistently excited by low threshold mechanical stimulation of the urethra and anus, respectively. (4) The axons from the bladder, urethra and anus were presumably myelinated (conduction velocity above 2 m/s) and conducted at 10.3±6.1 m/s (n=34, mean±SD), 26.3±9.3 m/s (n=13) and 9.5±5.1 m/s (n=37), respectively. The axons from the colon conducted at about 0.5 to 16 m/s (n=20), 13 of them conducting at less than 2 m/s. About 75% of the axons which could not be activated by mechanical stimulation of the visceral organs were presumably unmyelinated (conduction velocity below 2 m/s). (5) Some ongoing activity was found in 9 out of 26 afferent units from the anus but, with one exception, the afferent units from the bladder, urethra and colon were silent. (6) It is concluded that the pelvic afferent units from the urinary bladder, urethra, colon and anus consist of distinct populations with characteristic response patterns. There is no indication from this investigation that the urinary bladder is supplied by sacral afferents which are only recruited at high intravesical pressures during passive distension and isovolumetric contractions and which are possibly associated with pain.Supported by the Deutsche Forschungsgemeinschaft     

Effects of "Below-Zero" Habituation on the Electrodermal Orienting Response to a Test Stimulus

Two experiments were designed to investigate the effect of below-zero habituation training on skin conductance response (SCR) amplitude to a change in auditory stimulus frequency. In both experiments, subjects were trained with a 1000 Hz tone until zero responding and then received 5, 10, or IS further training trials. In Experiment 1 (N=45), subjects then received 1 presentation of a test stimulus of 1400 Hz, while in Experiment 2 (N=45), the test stimulus was a tone of 670 Hz. On the basis of dual-process theory, it was hypothesized that response amplitude to the test stimulus would be inversely related to amount of below-zero training. However, the results of both experiments indicate that SCR amplitude was positively related to amount of below-zero training. These results suggest that in situations of extended habituation training, an expectancy or subjective probability of stimulus occurrence gradient is important in determining response amplitude to a test stimulus.     

Die Beanspruchung des menschlichen Ellenbogengelenks

Zusammenfassung Bei 80 Objekten werden die Gelenkflächen des menschlichen Ellenbogengelenks untersucht. Die Trochlea und das Capitulum humeri sowie das Caput radii zeigen keine nennenswerten Unterschiede in der Ausdehnung der mit typischem Gelenkknorpel bedeckten Flächen. Dagegen lassen sich für die Ulnazange drei charakteristische Formgruppen abgrenzen: In 3 Fällen kann eine einheitliche Knorpelfläche beobachtet werden. Bei etwa zwei Drittel der untersuchten Objekte liegt im mittleren Bereich der Incisura trochlearis in horizontaler Richtung ein 2–5 mm breiter knorpelfreier Streifen, der den Gelenkknorpel in 2 vollständig getrennte Flächen unterteilt. Das restliche Drittel der Objekte besitzt eine unvollständige Trennung der Gelenkfläche. Unter Berücksichtigung der Vorstellungen von Pauwels über die causale Histogenese der mesenchymalen Stützgewebe sowie der Materialverteilung im Knochengewebe in Abhängigkeit von der einwirkenden Spannungsgröße werden die morphologischen Befunde den für die jeweiligen Skeletelemente von Pauwels ermittelten Spannungsdiagrammen gegenübergestellt. An der Trochlea und dem Capitulum humeri und am Caput radii findet sich eine geradezu ideale Übereinstimmung in der Ausdehnung der Knorpelfläche und der Knochendichte unter den Gelenkflächen mit den entsprechenden Spannungsdiagrammen. An der Ulna trifft dies nur für einen geringen Teil der Objekte zu. Für die unterschiedliche Ausgestaltung der Incisura trochlearis werden zwei mögliche Ursachen diskutiert: 1. die Resultierende R verharre während des Bewegungsablaufes in einzelnen Positionen innerhalb der Incisura trochlearis verschieden lange; 2. der Krümmungsradius der Trochlea humeri sei größer als derjenige im mittleren Bereich der Ulnazange, so daß hier wegen des fehlenden Kontaktes der Gelenkflächen keine Druckübertragung möglich ist.

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The stress of the human elbow jointI. Functional morphology of the articular surfaces

Summary The articular surfaces of 80 human elbow joints are analysed. The trochlea and capitulum humeri and the caput radii of the investigated individuals show no particular differences in the extent of their surfaces covered with typical articular cartilage. On the other hand the form of the incisura trochlearis is rather variable. Three characteristic formgroups are to be discerned. In three objects a continuous cartilage surface has been observed. In 50 of the investigated joints there is a small intersection free from cartilage in the midst of the incisura trochlearis, dividing the articular cartilage in two isolated surfaces. In the rest of the analysed objects the articular surface is divided only partially. According to Pauwels' hypothesis on the causal histogenesis of the mesenchymal supporting tissues and of the density distribution of the bone dependence upon the magnitude of the local unit stress the morphological findings in the single investigated parts of the elbow joint are confronted with the corresponding stress diagram as described by Pauwels. In the trochlea and capitulum humeri and in the caput radii a nearly ideal correspondence of the extent of the articular surface and the density of the bone tissue with the unit stress diagrams are found. In the ulna this correspondence exists only in few of the analysed objects. For the different form of the incisura trochlearis two possible explanations are discussed: 1, during the motion the resultant of forces may stay for a different time in their single positions in the incisura trochlearis; 2. the curvature radius of the trochlea humeri may be greater than that one of the incisura trochlearis in the central area. So no pressure occurs in this part of the articular surface.

Mit freundlicher Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Neuromagnetic investigation of somatotopy of human hand somatosensory cortex

Summary In order to investigate functional topography of human hand somatosensory cortex we recorded somatosensory evoked fields (SEFs) on MEG during the first 40 ms after stimulation of median nerve, ulnar nerve, and the 5 digits. We applied dipole modeling to determine the three-dimensional cortial representations of different peripheral receptive fields. Median nerve and ulnar nerve SEFs exhibited the previously described N20 and P30 components with a magnetic field pattern emerging from the head superior and re-entering the head inferior for the N20 component; the magnetic field pattern of the P30 component was of reversed orientation. Reversals of field direction were oriented along the anterior-posterior axis. SEFs during digit stimulation showed analogous N22 and P32 components and similar magnetic field patterns. Reversals of field direction showed a shift from lateral inferior to medial superior for thumb to little finger. Dipole modeling yielded good fits at these peak latencies accounting for an average of 83% of the data variance. The cortical digit representations were arranged in an orderly somatotopic way from lateral inferior to medial superior in the sequence thumb, index finger, middle finger, ring finger, and little finger. Median nerve cortical representation was lateral inferior to that of ulnar nerve. Isofield maps and dipole locations for these components are consistent with neuronal activity in the posterior bank of central fissure corresponding to area 3b. We conclude that SEFs recorded on MEG in conjunction with source localization techniques are useful to investigate functional topography of human hand somatosensory cortex non-invasively.     

The recovery of α-adrenoceptor function and binding sites after phenoxybenzamine

Summary The recovery of peripheral -adrenoceptor function and binding sites was studied in male New Zealand white rabbits after treatment with the irreversible adrenoceptor antagonist phenoxybenzamine. Phenoxybenzamine (5 mg/kg) was administered intravenously and the animals studied 30 min to 12 days later. Pressor dose response curves to intravenous phenylephrine, noradrenaline and guanabenz were constructed in vivo in conscious animals. The contractile response of abdominal aorta and renal artery to phenylephrine and noradrenaline was examined in vitro and the recovery of specific prazosin and clonidine binding to spleen membranes investigated in radioligand binding studies.The half life (t _1/2) for recovery of maximum pressor response in vivo ranged from 0.9±0.2 days for phenylephrine to 1.4±0.1 days for guanabenz. The t _1/2 for recovery of ED₅₀ was not significantly different to t _1/2 for recovery of maximum pressor response and ranged from 0.8±0.2 days for noradrenaline to 1.3±0.3 days for phenylephrine.Half life for recovery of maximum response and EC₅₀ in the isolated tissues was similar to that obtained in vivo for recovery of pressor responses and ranged from 0.4±0.1 days for the EC₅₀ of noradrenaline in the renal artery to 1.2±0.6 days for maximum response to phenylephrine in the abdominal aorta.The rate of recovery of specific clonidine binding did not differ significantly from the rate of recovery of pressor responses to the ₂-selective agonist guanabenz. t _1/2 for maximum number of specific clonidine binding sites, B _max was 1.6±0.9 days. However t _1/2 for recovery of specific prazosin binding was significantly longer than recovery of responses to phenylephrine and noradrenaline, t _1/2 for B _max was 3.6 ±0.1 day.     

The Application of Creatine Supplementation in Medical Rehabilitation

Numerous health conditions affecting the musculoskeletal, cardiopulmonary, and nervous systems can result in physical dysfunction, impaired performance, muscle weakness, and disuse-induced atrophy. Due to its well-documented anabolic potential, creatine monohydrate has been investigated as a supplemental agent to mitigate the loss of muscle mass and function in a variety of acute and chronic conditions. A review of the literature was conducted to assess the current state of knowledge regarding the effects of creatine supplementation on rehabilitation from immobilization and injury, neurodegenerative diseases, cardiopulmonary disease, and other muscular disorders. Several of the findings are encouraging, showcasing creatine’s potential efficacy as a supplemental agent via preservation of muscle mass, strength, and physical function; however, the results are not consistent. For multiple diseases, only a few creatine studies with small sample sizes have been published, making it difficult to draw definitive conclusions. Rationale for discordant findings is further complicated by differences in disease pathologies, intervention protocols, creatine dosing and duration, and patient population. While creatine supplementation demonstrates promise as a therapeutic aid, more research is needed to fill gaps in knowledge within medical rehabilitation.     

Applying the Stages of Change Model in a Nutrition Education Programme for the Promotion of Fruit and Vegetable Consumption among People with Severe Mental Disorders (DIETMENT)

Despite growing evidence of the benefits of adequate intake of fruit and vegetables (F&V) and the recommendation to consume five servings daily, the adoption of these habits is poor among people with severe mental disorder (SMD). The main aim of the present study is to determine changes in the intake of F&V and motivation to do so among people with SMDs after participating in a food education programme. A community-based randomized controlled trial was conducted in Spain, with the intervention group (IG) participating in a food education programme based on the stages of change model to promote consumption of F&V and the control group (CG) receiving three informative sessions on basic healthy eating. The main outcomes were related to the intake of F&V and stages of change. Data collection was performed at baseline, post intervention, and 12-month follow-up. Seventy-four participants enrolled in the study and sixty completed the 12-month follow-up. An increase in motivation towards the intake of F&V was observed in the IG but not in the CG (McNemar’s test p = 0.016, p = 0.625). No significant difference was observed for the intake of fruit, vegetables, or F&V. Basing food education strategies on the stages of change model shows positive results, increasing the awareness and disposition of people with SMD towards the intake of F&V. More research is needed to identify the most appropriate eating intervention to increase the intake of F&V.     

Giving a voice to patient experiences through the insights of pragmatism

As a philosophical position, pragmatism can be critiqued to distinguish truth only with methods that bring about desired results, predominantly with scientific enquiry. The article hopes to dismiss this oversimplification and propose that within mental health nursing, enquiry enlightened by pragmatism can be anchored to methods helping to tackle genuine human problems. Whilst pragmatists suggest one reality exists, fluctuating experiences and shifting beliefs about the world can inhabit within; hence, pragmatists propose reality has the potential to change. Moreover, pragmatism includes being cognisant of what works to whom reality concerns, making reality context-driven, with a view to understand how actions shape experiences so what is generated has usefulness. Hence, it somewhat follows pragmatism can inform mental health nursing, after all, nursing is a discipline of action, and awareness is needed in how actions produce experiences that patients find helpful. Given the principles of recovery are preferably adopted in mental health care, the paper will explore how pragmatism can help nurses move towards that goal; specifically, with patients voicing their experiences. This is because like pragmatism, recovery subscribes to hope that reality can progress, and through meaningful experiences and beliefs, patients have expertise about personal difficulties alongside how life may flourish, despite mental illness.     

Machine Learning Algorithms to Predict Mortality and Allocate Palliative Care for Older Patients With Hip Fracture

ObjectivesTo evaluate a machine learning model designed to predict mortality for Medicare beneficiaries aged >65 years treated for hip fracture in Inpatient Rehabilitation Facilities (IRFs).DesignRetrospective design/cohort analysis of Centers for Medicare & Medicaid Services Inpatient Rehabilitation Facility–Patient Assessment Instrument data.Setting and ParticipantsA total of 17,140 persons admitted to Medicare-certified IRFs in 2015 following hospitalization for hip fracture.MeasuresPatient characteristics include sociodemographic (age, gender, race, and social support) and clinical factors (functional status at admission, chronic conditions) and IRF length of stay. Outcomes were 30-day and 1-year all-cause mortality. We trained and evaluated 2 classification models, logistic regression and a multilayer perceptron (MLP), to predict the probability of 30-day and 1-year mortality and evaluated the calibration, discrimination, and precision of the models.ResultsFor 30-day mortality, MLP performed well [acc = 0.74, area under the receiver operating characteristic curve (AUROC) = 0.76, avg prec = 0.10, slope = 1.14] as did logistic regression (acc = 0.78, AUROC = 0.76, avg prec = 0.09, slope = 1.20). For 1-year mortality, the performances were similar for both MLP (acc = 0.68, AUROC = 0.75, avg prec = 0.32, slope = 0.96) and logistic regression (acc = 0.68, AUROC = 0.75, avg prec = 0.32, slope = 0.95).Conclusion and ImplicationsA scoring system based on logistic regression may be more feasible to run in current electronic medical records. But MLP models may reduce cognitive burden and increase ability to calibrate to local data, yielding clinical specificity in mortality prediction so that palliative care resources may be allocated more effectively.