In vivo release and turnover of secreted platelet antiheparin proteins in rhesus monkey (Macaca mulatta)

Human and rhesus monkey platelets secrete at least two antiheparin proteins: platelet factor 4 (PF4) and low affinity platelet factor 4 (LA-PF4). Neither of these proteins showed species-related antigenic differences. As determined by radioimmunoassay, the levels of PF4 and LA-PF4 antigen per 10(9) monkey platelets amounted to 10.7 and 20.3 microgram, respectively. One milliliter of monkey plasma prepared from blood collected into an anticoagulant composed of EDTA, prostaglandin E1, and theophylline solution contained 22.4 ng LA-PF4 and 8.0 ng PF4. Concentrations of these two platelet-specific proteins in monkeys closely resembled levels found in human platelets and plasma. Infusion of prostacyclin (PGI2) (100 or 300 ng/kg/min) into monkeys for 15 min resulted in a significant decrease of plasma levels of LA-PF4 antigen and of PF4 by 40%--60% (p < 0.0001). This decrease was related to the inhibitory effect of PGI2 on the secretion of platelets stimulated by a catheter or by venipuncture. Longer infusion of PGI2 did not produce further significant change. The supernate obtained after aggregation of human platelets stimulated by thrombin was injected into monkeys receiving PGI2 infusion. The disappearance of LA-PF4 antigen in monkey plasma followed a biphasic exponential curve with half-lives for the fast and slow components of 8.4 and 63 min. PF4 disappeared faster but followed the same pattern (half-lives for the fast and slow component of 2.1 and 70 min). Analysis of the experimental data suggests that the low levels of secreted platelet proteins in monkey plasma are related to their minimal in vivo release and to their rapid clearance.     

Morphological variability is greater at developing than mature mouse neuromuscular junctions

The neuromuscular junction (NMJ) is the highly specialised peripheral synapse formed between lower motor neuron terminals and muscle fibres. Post-synaptic acetylcholine receptors (AChRs), which are found in high density in the muscle membrane, bind to acetylcholine released into the synaptic cleft of the NMJ, thereby enabling the conversion of motor action potentials to muscle contractions. NMJs have been studied for many years as a general model for synapse formation, development and function, and are known to be early sites of pathological changes in many neuromuscular diseases. However, information is limited on the diversity of NMJs in different muscles, how synaptic morphology changes during development, and the relevance of these parameters to neuropathology. Here, this crucial gap was addressed using a robust and standardised semi-automated workflow called NMJ-morph to quantify features of pre- and post-synaptic NMJ architecture in an unbiased manner. Five wholemount muscles from wild-type mice were dissected and compared at immature (post-natal day, P7) and early adult (P31−32) timepoints. The inter-muscular variability was greater in mature post-synaptic AChR morphology than that of the pre-synaptic motor neuron terminal. Moreover, the developing NMJ showed greater differences across muscles than the mature synapse, perhaps due to the observed distinctions in synaptic growth between muscles. Nevertheless, the amount of nerve to muscle contact was consistent, suggesting that pathological denervation can be reliably compared across different muscles in mouse models of neurodegeneration. Additionally, mature post-synaptic endplate diameters correlated with fibre type, independently of muscle fibre diameter. Altogether, this work provides detailed information on healthy pre- and post-synaptic NMJ morphology from five anatomically and functionally distinct mouse muscles, delivering useful reference data for future comparison with neuromuscular disease models.     

The functional half-life of H-2Kd-restricted T cell epitopes on living cells

The functional half-life (t_1/2) of different complexes formed by major histocompatibility complex (MHC) class I molecules and antigen on the surface of target cells was measured using specific cytotoxic T lymphocyte (CTL) clones in cytolysis, and interferon-γ-production and Ca²⁺-mobilization assays. Functional t_1/2 values of 5–10 h were obtained, which are in accordance with some previous estimations obtained from biochemical and immunochemical measurements. Moreover, these values were independent of the type of target cell, fixation of the target cells, or proteases able to degrade the peptides, suggesting that the unfolding of the peptide/MHC complexes at the cell surface alone determines the functional t_1/2 of the CTL epitopes.     

Significant GH deficiency after long-term cure by surgery in adult patients with Cushing's disease

OBJECTIVE: Impaired GH secretion usually accompanies Cushing's syndrome and a variable proportion of patients reportedly fail to recover normal GH secretion after successful treatment. This wide variability is most probably due to differences in the treatment (i.e. surgery and/or radiotherapy), timing of patient re-evaluation after surgery and dynamic tests employed to challenge GH secretion, and hinders a precise assessment of risk of GH deficiency after cure. The aim of the present study is to evaluate GH secretory status after long-term cure of Cushing's disease achieved by surgery alone. DESIGN AND METHODS: We studied 34 patients (27 females and 7 males, age range 21-68 years) formerly affected by Cushing's disease. Patients were studied 2-20 years (median 3.3 years) following remission of hypercortisolism; all patients underwent transsphenoidal surgery with the removal of an ACTH-secreting adenoma; repeat pituitary surgery for relapse was performed in two patients while bilateral adrenalectomy was necessary in two patients. In all subjects, the GH response to GHRH+arginine stimulation was evaluated. At the time of testing, 13 patients were still on steroid replacement therapy. RESULTS: In long-term surgical remission, 22 patients (65.0%) presented subnormal GH secretion; partial GH deficiency (GH peak <16.5 microg/l) was found in 11 patients and severe GH deficiency (GH peak <9 microg/l) in another 11. Male gender and length of hypercortisolism were risk factors for postsurgical GH deficiency. CONCLUSIONS: This study demonstrates the presence of GH deficiency in a high percentage of patients with Cushing's disease after long-term remission of hypercortisolism obtained by surgery alone. Male gender and length of hypercortisolism are the most significant predictors of postsurgical GH deficiency. This finding is significant as it highlights that even the most favourable therapeutical course, i.e. remission achieved by surgery alone, is accompanied by impaired GH secretion. Assessment of GH secretion is therefore recommended for all patients cured from Cushing's disease, even if not submitted to radiotherapy. Studies on the clinical impact of GH deficiency and the use of GH replacement therapy seem warranted in patients cured from Cushing's disease.     

The structural and functional mechanisms of motor recovery: complementary use of diffusion tensor and functional magnetic resonance imaging in a traumatic injury of the internal capsule

OBJECTIVES—Recovery from focal motor pathwaylesions may be associated with a functional reorganisation of corticalmotor areas. Previous studies of the relation between structural braindamage and the functional consequences have employed MRI and CT, whichprovide limited structural information. The recent development ofdiffusion tensor imaging (DTI) now provides quantitative measures offibre tract integrity and orientation. The objective was to use DTI andfunctional MRI (fMRI) to determine the mechanisms underlying theexcellent recovery found after a penetrating injury to the rightcapsular region.
METHODS—DTI and fMRI were performed on the patientdescribed; DTI was performed on five normal controls.
RESULTS—The injury resulted in a left hemiplegiawhich resolved fully over several weeks. When studied 18 months laterthere was no pyramidal weakness, a mild hemidystonia, and sensorydisturbance. fMRI activation maps showed contralateral primary andsupplementary motor cortex activation during tapping of each hand;smaller ipsilateral primary motor areas were activated by the recoveredhand only. DTI disclosed preserved structural integrity and orientationin the posterior capsular limb by contrast with the disrupted structure in the anterior limb on the injured side.
CONCLUSIONS—The findings suggest that the mainrecovery mechanism was a preservation of the integrity and orientationof pyramidal tract fibres. The fMRI studies do not suggest substantialreorganisation of the motor cortex, although ipsilateral pathways mayhave contributed to the recovery. The initial deficit was probably dueto reversible local factors including oedema and mass effect; permanentdamage to fibre tracts in the anterior capsular limb may account for the persistent sensory deficit. This study shows for the first time thepotential value of combining fMRI and DTI together to investigatemechanisms of recovery and persistent deficit in an individual patient.

     

Energy efficiency and nutrition in societies based on human labor

Improving the conditions of poor traditional societies is a standard goal of development policies. The definition of ‘improvement’ requires a previous definition of values, that is to say, ‘better’ or ‘worse’ can change according to the parameters used to optimize the system. Different scientific disciplines generally focus on different levels of analysis: the individual, the socio‐economic, or the environmental level. Consequently, optimization parameters derived from single disciplines are not holistic in assessing development. System energy analysis can provide a way to describe the interaction among individuals, human societies and natural processes, that bridges the different levels of analysis.

This paper investigates the relationship between nutrition and energy efficiency in farming systems based on human labor. By describing the energetic budget of a society, trade‐offs can be assessed between a better diet at individual level, and the consequent decrease in the conversion ratio of energy input into applied power at societal level (more elderly, larger body size, dramatic increase of energetic cost for nutritional calories). The relationship between energy efficiency and nutrition in the process of societal development is also addressed.     

Effects of 17β-oestradiol on rat detrusor smooth muscle contractility

The aim of this study was to investigate the effect of 17β-oestradiol (E₂) on detrusor smooth muscle contractility and its possible neuroprotective role against ischaemic-like condition, which could arise during overactive bladder disease. The effect of E₂ was investigated on rat detrusor muscle strips stimulated with carbachol, KCl and electrically, in the absence or presence of a selective oestrogen receptor antagonist (ICI 182,780) and, by using confocal Ca²⁺ imaging technique, measuring the amplitude (Δ F / F ₀) and the frequency of spontaneous whole cell Ca²⁺ flashes. Moreover, the effect of 1 and 2 h of anoxia–glucopenia and reperfusion (A-G/R), in the absence or presence of the hormone, was evaluated in rat detrusor strips perfused with Krebs solution which underwent electrical field stimulation to stimulate intrinsic nerves; the amplitude and the frequency of Ca²⁺ flashes were also measured. 17β-Oestradiol exhibited antispasmogenic activity assessed on detrusor strips depolarized with 60 m m KCl at two different Ca²⁺ concentrations. 17β-Oestradiol at the highest concentration tested (30 μ m ) significantly decreased detrusor contractions induced by all the stimuli applied. In addition, the amplitude and the frequency of spontaneous Ca²⁺ flashes were significantly decreased in the presence of E₂ (10 and 30 μ m ) compared with control detrusor strips. In strips subjected to A-G/R, a significant increase in the amplitude of both spontaneous and evoked flashes was observed. 17β-Oestradiol was found to increase the recovery of detrusor strips subjected to A-G/R. The ability of E₂ to suppress contraction in control conditions may explain its ability to aid recovery following A-G/R.     

Trialogue

Hyperglycaemic patients admitted to hospital have worse clinical outcomes with higher operational costs than normoglycaemic patients. Identifying, defining and treating hyperglycaemia promptly and appropriately is essential during hospitalisation; adequate ‘continuity of care’ must be assured after discharge. This requires a multidisciplinary clinical collaboration between the internist and the diabetes team, which plays a central role in the treatment course and should be involved soon after patient admission to the hospital. This document aims to establish guidelines and recommendations for good clinical practice in managing hyperglycaemic internal medicine patients, with or without previous diagnosis of diabetes. The Associazione Medici Diabetologi (AMD), Federazione delle Associazioni dei Dirigenti Ospedalieri Internisti (FADOI) and Società Italiana di Diabetologia (SID) have decided to publish a document useful for internists in the management of hospitalised patients with hyperglycaemia. The Trialogue project, coordinated by a Board of Scientific Experts from the three scientific societies, was initiated for this purpose. A questionnaire consisting of 16 multiple choice questions on the management of hyperglycaemia in hospital was answered by 660 physicians from over 250 Internal Medicine units distributed throughout Italy. Analysis of responses has yielded an overview of routine clinical practice and provided a wealth of ideas to better identify critical points in the treatment of hospitalised patients with hyperglycaemia. These recommendations were developed with the aim of providing mutually agreed practical guidance (instructions for use) that can be readily applied by healthcare professionals in routine clinical practice.