Muscle Disuse as a Pivotal Problem in Sarcopenia-related Muscle Loss and Dysfunction.

An age-associated loss of muscle mass and strength--sarcopenia--begins at around the fifth decade of life, with mass being lost at ~0.5-1.2% per year and strength at ~3% per year. Sarcopenia can contribute to a variety of negative health outcomes, including an increased risk for falls and fractures, the development of metabolic diseases like type 2 diabetes mellitus, and increase the chance of requiring assisted living. Linear sarcopenic declines in muscle mass and strength are, however, punctuated by transient periods of muscle disuse that can accelerate losses of muscle and strength, which could result in increased risk for the aforementioned conditions. Muscle disuse is recognizable with bed rest or immobilization (for example, due to surgery or acute illness requiring hospitalization); however, recent work has shown that even a relative reduction in ambulation (reduced daily steps) results in significant reductions in muscle mass, strength and possibly an increase in disease risk. Although reduced ambulation is a seemingly "benign" form of disuse, compared to bed rest and immobilization, reports have documented that 2-3 weeks of reduced daily steps may induce: negative changes in body composition, reductions in muscle strength and quality, anabolic resistance, and decrements in glycemic control in older adults. Importantly, periods of reduced ambulation likely occur fairly frequently and appear more difficult to fully recover from, in older adults. Here we explore the consequences of muscle disuse due to reduced ambulatory activity in older adults, with frequent comparisons to established models of disuse: bed rest and immobilization.

The effect of exercise mode on the acute response of satellite cells in old men.

AIM: A dysregulation of satellite cells may contribute to the progressive loss of muscle mass that occurs with age; however, older adults retain the ability to activate and expand their satellite cell pool in response to exercise. The modality of exercise capable of inducing the greatest acute response is unknown. We sought to characterize the acute satellite cell response following different modes of exercise in older adults. METHODS: Sedentary older men (n = 22; 67 ± 4 years; 27 ± 2.6 kg*m(-2) ) were randomly assigned to complete an acute bout of either resistance exercise, high-intensity interval exercise on a cycle ergometer or moderate-intensity aerobic exercise. Muscle biopsies were obtained before, 24 and 48 h following each exercise bout. The satellite cell response was analysed using immunofluorescent microscopy of muscle cross sections. RESULTS: Satellite cell expansion associated with type I fibres was observed 24 and 48 h following resistance exercise only (P ˂ 0.05), while no expansion of type II-associated satellite cells was observed in any group. There was a greater number of activated satellite cells 24 h following resistance exercise (pre: 1.3 ± 0.1, 24 h: 4.8 ± 0.5 Pax7 + /MyoD+cells/100 fibres) and high-intensity interval exercise (pre: 0.7 ± 0.3, 24 h: 3.1 ± 0.3 Pax7 + /MyoD+cells/100 fibres) (P ˂ 0.05). The percentage of type I-associated SC co-expressing MSTN was reduced only in the RE group 24 h following exercise (pre: 87 ± 4, 24 h: 57 ± 5%MSTN+ type I SC) (P < 0.001). CONCLUSION: Although resistance exercise is the most potent exercise type to induce satellite cell pool expansion, high-intensity interval exercise was also more potent than moderate-intensity aerobic exercise in inducing satellite cell activity.

Characterisation of Rep-encoding components associated with banana bunchy top nanovirus in Vietnam.

We have analysed the sequence variability of the banana bunchy top nanovirus (BBTV) DNA-1 sequence from 17 isolates collected throughout Vietnam, and showed that the level of DNA-1 sequence variation within Vietnam was approximately double that previously reported for Asian BBTV isolates. Furthermore, the sequences separated into two geographical subgroups that generally correlated to the northern or southern regions of Vietnam. We have also characterised an additional putative Rep-encoding component associated with some BBTV isolates from Vietnam. This component, which we have named BBTV-S3, shared 47%, 69%, 56% and 65% nucleotide sequence identity with the previously reported Rep-encoding components BBTV DNA-1, S1, S2 and Y1 respectively.

An evaluation of how MRI is used as a pre-operative screening investigation in patients with temporal lobe epilepsy.

AIMS: A retrospective analysis was carried out of how magnetic resonance imaging (MRI) is used as a pre-operative screening investigation in patients with a clinical diagnosis of medically intractable temporal lobe epilepsy (TLE). Up to 65% of such patients are said to have hippocampal sclerosis (HS). MATERIALS AND METHODS: Forty-six patients in a 26-month period underwent MR examination on a 1.5 T scanner according to a routine protocol. Each patient had coronal T1-weighted and oblique coronal T2-weighted scans performed. Hippocampal volume was calculated from the T1-weighted images, the T2-weighted images being assessed for relative hippocampal signal intensity. Each individual patient's medical records were audited. RESULTS: Thirty per cent of patients in our study had a diagnosis of HS made on their MR scan. No patient had a diagnosis of HS made without prior clinical evidence of seizure lateralization. Sixty-eight per cent of patients with clinical evidence of a unilateral seizure focus had HS diagnosed by MR scanning. Forty-three per cent of patients did not have clinical evidence of an unilateral seizure focus. It was found that over 25% of patients referred to the unit did not fit the criteria of having medically intractable TLE. Nine per cent of patients had previously stated that they did not want epilepsy surgery. CONCLUSION: The lower than expected diagnostic rate of HS in this patient population reflects the broad criteria used in referring patients for imaging studies. This is likely to mirror the initial investigation of these patients outside specialist units where more extensive investigation prior to MRI is available. However, when MRI is used as an initial screening investigation, this study indicates that implementation of simple clinical criteria should significantly reduce the number of unnecessary scans.

Initial experience with a electronic CT image transfer system.

An electronic image transfer system for computed tomographic images links the CT scanner in Altnagelvin Hospital, Londonderry with the regional neuroradiology department in the Royal Victoria Hospital, Belfast. In the first 13 months of operation, scans of 100 patients were transferred; 49 scans were taken in acute neurosurgical emergencies, and 51 were non-acute sent for a specialist neuroradiological opinion. Potentially hazardous inter-hospital transfer was avoided in 21 cases of acute neurosurgical emergency, and more efficient and appropriate referral was achieved in the cases whose scans had been sent for sent for radiological second opinion. We believe that the system has substantially improved the diagnosis and management of patients with neurosurgical problems in both hospitals.

The value of repeat cerebral angiography in subarachnoid haemorrhage.

In 216 consecutive patients investigated for subarachnoid haemorrhage, 44 (20.3%) of cerebral angiograms were either normal or equivocal for the presence of aneurysm. Arteriography was repeated in 30 patients and an aneurysm was demonstrated in 10 cases. Repeat arteriography is recommended in proven subarachnoid haemorrhage even when the initial study is normal, and in this study achieved a reduction in overall negative rate to 15.6%.

High school driver education using peer tutors, direct instruction, and precision teaching.

The authors investigated the combined effects of direct instruction and precision teaching by peer tutors in a high school driver education curriculum. Learners (N = 4) included students with intellectual and learning disabilities and students without disabilities. Peer tutoring was associated with immediate increases in correct responding and a simultaneous and rapid deceleration of errors. Three learners passed the written tests in the driver education classroom, obtained driver's licenses, and produced similar or better driving records than students who did not require assistance. This program is being continued and expanded by school personnel without assistance from the authors.

Serpentine aneurysm of the posterior circulation: report of two cases.

Giant serpentine aneurysms form a subgroup of giant intracranial aneurysms with specific radiological and surgical features. Previous reports have stressed the predilection of these lesions for the carotid circulation, particularly the middle cerebral artery. Two cases of serpentine aneurysm affecting the posterior circulation are reported and the problems of diagnosis and treatment of this lesion are discussed.

Certified nurse-midwife effectiveness in the health maintenance organization obstetric team.

This study of the effectiveness of certified nurse-midwives in a health maintenance organization (HMO) led to five conclusions: 1) Maternity patients accepted certified nurse-midwife care; 2) the general female HMO population had little awareness of certified nurse-midwives but was receptive to receiving certified nurse-midwife care once the role was explained; 3) certified nurse-midwives reduced inpatient cost; 4) the use of certified nurse-midwives did not affect perinatal outcomes; and 5) physicians and certified nurse-midwives worked well together as team members. Certified nurse-midwives proved to be an unqualified success as team members in this setting.

Iopamidol in the diagnosis of suspected upper gastro-intestinal perforation.

Forty patients, mainly post-operative, were examined for suspected leakage from the oesophagus and/or stomach using iopamidol. Oesophageal leaks were demonstrated in seven patients, tracheo-oesophageal fistulae in two and an unsuspected gastro-jejunostomy intusussception in one. Only two cases were regarded as technically unsatisfactory due to poor coating. Normal examinations were found in 28 (70%) patients. This was confirmed by the subsequent clinical course. Aspiration into the bronchial tree occurred in five (12.5%) patients without ill-effects. Furthermore no adverse side effects as a result of the administration of iopamidol were recorded. It is concluded that a non-ionic medium such as iopamidol is the agent of choice in the detection of oesophageal and gastric perforation, particularly in post-operative patients where there is an increased risk of aspiration.

Steroid-induced Kaposi's sarcoma in a patient with pre-AIDS.

Kaposi's sarcoma is known to occur in a variety of immunosuppressed patients. The course of the disease varies depending on the underlying risk factors. A male homosexual patient in whom Kaposi's sarcoma developed while he was being treated with prednisone for Henoch-Schönlein purpura is described. The resolution of his lesions once the steroid was discontinued places him in the group of patients whose main risk factor is the steroid itself, rather than the acquired immune deficiency syndrome (AIDS) risk group. A review of the literature on steroid-treated patients in whom Kaposi's sarcoma developed is presented.