Effects of isometric resistance training and detraining on ambulatory blood pressure and morning blood pressure surge in young normotensives.

Isometric resistance training (IRT) has been shown to reduce resting and ambulatory blood pressure (BP), as well as BP variability and morning BP surge (MBPS). However, there are no data available regarding how long after cessation of IRT these effects are maintained. Therefore, the purpose of this study was to determine the effects of 8 weeks of detraining on resting BP, ambulatory BP and MBPS following 8 weeks of IRT in a population of young normotensive individuals and to further substantiate previously reported reductions in MBPS following IRT. Twenty-five apparently healthy participants with resting BP within the normal range (16 men, age = 23 ± 6 years; 9 women, age = 22 ± 4 years, resting BP: 123 ± 5/69 ± 7 mmHg) were randomly assigned to a training-detraining (TRA-DT, n = 13) or control (CON, n = 12) group. Resting BP, ambulatory BP and MBPS were measured prior to, after 8 weeks of bilateral leg IRT using an isokinetic dynamometer (4 × 2-min contractions at 20% MVC with 2-min rest periods, 3 days/week) and following an 8-week detraining period. There were significant reductions in 24-h ambulatory systolic BP (SBP) and calculated SBP average real variability (ARV) following IRT that were maintained after detraining (pre-to-post detraining, -6 ± 4 mmHg, p = 0.008, -2 ± 1.5 mmHg, p = 0.001). Similarly, the training-induced decreases in daytime SBP and daytime SBP ARV (pre-to-post detraining, -5 ± 6 mmHg, p = 0.001; -2 ± 1.2 mmHg, p = 0.001, respectively), MBPS (pre-to-post detraining, -6 ± 9 mmHg, p = 0.046) and resting SBP (pre-to-post detraining, -4 ± 6 mmHg, p = 0.044) were preserved. There were no changes in night-time or night-time SBP ARV across all time points (pre-to-post detraining, -1 ± 8 mmHg, p = 1.00, -0.7 ± 2.9 mmHg, p = 1.00). These results confirm that IRT causes significant reductions in resting BP, ambulatory BP, ambulatory ARV and MBPS. Importantly, the changes remained significantly lower than baseline for 8 weeks after cessation of training, suggesting a sustained effect of IRT.

A mixed-method process evaluation of an East Midlands county summer 2021 holiday activities and food programme highlighting the views of programme co-ordinators, providers, and parents.

Background: The Holiday Activities and Food (HAF) Programme is a UK Government initiative created to alleviate food insecurity and promote health and well-being among children and their families, who are eligible for Free School Meals (FSM), during the school holidays. This process evaluation investigated factors that facilitated and acted as a barrier to the delivery of the HAF Programme from the perspectives of key stakeholders (Co-ordinators, Providers, and Parents) involved in the HAF Programme across an East Midlands county. Methods: This evaluation utilized a mixed-methods approach, incorporating focus groups and online surveys to gain rich, multifaceted data. The focus groups were analyzed using a hybrid inductive-deductive thematic analysis and the online surveys were analyzed using mixed-methods approach due to the variation in question type (i.e., quantitative, Likert scale and open response) to align themes to the Government Aims and Standards of the HAF Programme. Findings: The stakeholders highlighted several factors that facilitated and acted as a barrier to the delivery of the HAF Programme. Facilitating factors included existing and maintaining relationships between Co-ordinators, Providers, and facilities/schools/communities as this improved communication and attendance. Additionally, transport provision for those attending the Programme helped overcome barriers to attendance. The primary barrier of the Programme was the late awarding of the Programme contract as this limited the time available to prepare and organize the Programme. This in turn, had several "knock on" effects that created more barriers and resulted in some of the Government Aims and Standards not being met such as, nutrition education for children and parents. Despite the challenges faced, Co-ordinators and Providers were able to deliver the Programme and positively impact upon the children and their families that attended the Programme. Conclusion: Following the facilitators and barriers that were highlighted in this evaluation, several recommendations have been made to enhance the delivery of the HAF Programme and ensure Government Aims and Standards, to improve children and family's health and well-being, are attained.

Effects of external loads on postural sway during quiet stance in adults aged 20-80 years.

The purpose of this study was to investigate the effects of holding external loads on postural sway during upright stance across age decades. Sixty-five healthy adults (females, n = 35), aged 18-80 years were assessed in four conditions; (1) standing without holding a load, holding a load corresponding to 5% body mass in the (2) left hand, (3) right hand and (4) both hands. The centre of pressure (COP) path length and anteroposterior and mediolateral COP displacement were used to indirectly assess postural sway. External loading elicited reductions in COP measures of postural sway in older age groups only (P < 0.05). No changes were observed in younger or intermediate aged adults (P > 0.05). Holding external loads during standing is relevant to many activities of daily living (i.e. holding groceries). The reduction in postural sway may suggest this type of loading has a stabilising effect during quiet standing among older adults.

Range of motion, neuromechanical, and architectural adaptations to plantar flexor stretch training in humans.

The neuromuscular adaptations in response to muscle stretch training have not been clearly described. In the present study, changes in muscle (at fascicular and whole muscle levels) and tendon mechanics, muscle activity, and spinal motoneuron excitability were examined during standardized plantar flexor stretches after 3 wk of twice daily stretch training (4 × 30 s). No changes were observed in a nonexercising control group (n = 9), however stretch training elicited a 19.9% increase in dorsiflexion range of motion (ROM) and a 28% increase in passive joint moment at end ROM (n = 12). Only a trend toward a decrease in passive plantar flexor moment during stretch (-9.9%; P = 0.15) was observed, and no changes in electromyographic amplitudes during ROM or at end ROM were detected. Decreases in H(max):M(max) (tibial nerve stimulation) were observed at plantar flexed (gastrocnemius medialis and soleus) and neutral (soleus only) joint angles, but not with the ankle dorsiflexed. Muscle and fascicle strain increased (12 vs. 23%) along with a decrease in muscle stiffness (-18%) during stretch to a constant target joint angle. Muscle length at end ROM increased (13%) without a change in fascicle length, fascicle rotation, tendon elongation, or tendon stiffness following training. A lack of change in maximum voluntary contraction moment and rate of force development at any joint angle was taken to indicate a lack of change in series compliance of the muscle-tendon unit. Thus, increases in end ROM were underpinned by increases in maximum tolerable passive joint moment (stretch tolerance) and both muscle and fascicle elongation rather than changes in volitional muscle activation or motoneuron pool excitability.

Can resource costs of polyploidy provide an advantage to sex?

The predominance of sexual reproduction despite its costs indicates that sex provides substantial benefits, which are usually thought to derive from the direct genetic consequences of recombination and syngamy. While genetic benefits of sex are certainly important, sexual and asexual individuals, lineages, or populations may also differ in physiological and life history traits that could influence outcomes of competition between sexuals and asexuals across environmental gradients. Here, we address possible phenotypic costs of a very common correlate of asexuality, polyploidy. We suggest that polyploidy could confer resource costs related to the dietary phosphorus demands of nucleic acid production; such costs could facilitate the persistence of sex in situations where asexual taxa are of higher ploidy level and phosphorus availability limits important traits like growth and reproduction. We outline predictions regarding the distribution of diploid sexual and polyploid asexual taxa across biogeochemical gradients and provide suggestions for study systems and empirical approaches for testing elements of our hypothesis.

Neuromuscular factors influencing the maximum stretch limit of the human plantar flexors.

Maximum joint range of motion is an important parameter influencing functional performance and musculoskeletal injury risk. Nonetheless, a complete description of the muscle architectural and tendon changes that occur during stretch and the factors influencing maximum range of motion is lacking. We measured muscle-tendon elongation and fascicle lengthening and rotation sonographically during maximal plantar flexor stretches in 21 healthy men. Electromyogram (EMG) recordings were obtained synchronously with ultrasound and joint moment data, and H-reflex measurements were made with the ankle at neutral (0°) and dorsiflexed (50% maximal passive joint moment) positions; the maximum H amplitude (normalized to maximum M-wave amplitude; M(max)) and H-amplitude elicited at a stimulation intensity that evoked 10% M(max) were obtained. Maximal stretch was accomplished through significant muscle (14.9%; 30 mm) and tendon lengthening (8.4%; 22 mm). There were similar relative changes in fascicle length and angle, but planimetric modeling indicated that the contribution of fascicle rotation to muscle lengthening was small (<4 mm). Subjects with a greater range of motion showed less resistance to stretch and a greater passive joint moment at stretch termination than less flexible subjects (i.e., greater stretch tolerance). Also, greater fascicle rotation accompanied muscle elongation (9.7 vs. 5.9%) and there was a greater tendon length at stretch termination in more flexible subjects. Finally, a moderate correlation between the angle of EMG onset and maximum range of motion was obtained (r = 0.60, P < 0.05), despite there being no difference in H-reflex magnitudes between the groups. Thus clear differences in the neuromuscular responses to stretch were observed between "flexible" and "inflexible" subjects.

Plantarflexor stretch training increases reciprocal inhibition measured during voluntary dorsiflexion.

Agonist-mediated reciprocal inhibition (RI) in distal skeletal muscles is an important neurophysiological phenomenon leading to improved movement coordination and efficiency. It has been shown to be reduced in aged and clinical populations, so the development of interventions augmenting RI is an important research goal. We examined the efficacy of using chronic passive muscle stretching to augment RI. The influence of 3 wk of plantarflexor stretching (4 × 30 s, two times/day) on RI of soleus and gastrocnemius initiated by tonic, voluntary dorsiflexion contractions [20% of maximum voluntary contraction (MVC)] was examined in 11 healthy men who performed stretch training and in nine nontraining controls. Hoffmann's reflexes (H-reflexes) were elicited by tibial nerve stimulation during both weak isometric (2% MVC) plantarflexions and dorsiflexion contractions at 20% MVC. Changes were examined at three joint angles, normalized to each subject's range of motion (ROM; plantarflexed = 10 ± 0°, neutral = -3.3 ± 2.9°, dorsiflexed = -16.5 ± 5.6°). No changes were detected in controls. A 20% increase in ROM in the stretch subjects was associated with a significant decrease in maximum H-reflex (H(max)): maximum evoked potential (M(max)), measured during 2% plantarflexion at the plantarflexed and neutral angles in soleus and at the plantarflexed angle in gastrocnemius (P < 0.05-0.01). By contrast, decreases in H(max):M(max) during 20% dorsiflexion contract were also seen at each angle in soleus and at the dorsiflexed angle in gastrocnemius. However, a greater decrease in H(max):M(max) measured during voluntary dorsiflexion rather than during plantarflexion, which indicates a specific change in RI, was detected only at the dorsiflexed angle (-30.7 ± 9.4% and -35.8 ± 6.8% for soleus and gastrocnemius, respectively). These results demonstrate the efficacy of soleus-gastrocnemius stretch training in increasing agonist-mediated RI from tibialis anterior onto soleus-gastrocnemius in young, healthy individuals at dorsiflexed, but not plantarflexed, joint angles.

Can phosphorus limitation contribute to the maintenance of sex? A test of a key assumption.

Why sex is so common remains unclear; what is certain is that the predominance of sex despite its profound costs means that it must confer major advantages. Here, we use elemental and nucleic acid assays to evaluate a key element of a novel, integrative hypothesis considering whether sex might be favoured because of differences in body composition between sexuals and asexuals. We found that asexual Potamopyrgus antipodarum, a New Zealand snail, have markedly higher bodily phosphorus and nucleic acid content per unit mass than sexual counterparts. These differences coincide with and are almost certainly linked to the higher ploidy of the asexuals. Our results are the first documented body composition differences between sexual and asexual organisms, and the first detected phenotypic difference between sexual and asexual P. antipodarum, an important natural model system for the study of the maintenance of sex. These findings also verify a central component of our hypothesis that competition between diploid sexuals and polyploid asexuals could be influenced by phosphorus availability.

Remodelling of cerebrospinal fluid lipoproteins after subarachnoid hemorrhage.

Lipoprotein particles (Lps) in normal human cerebrospinal fluid (CSF) are distinct from those found in plasma and include unique apolipoprotein E (apoE indicates protein; APOE, gene) containing lipoproteins rarely seen in human plasma. Less favourable neurological recovery after subarachnoid hemorrhage (SAH) has been observed in patients who possess the APOE epsilon4 allele raising the possibility that apoE influences neuronal survival after brain injury. We analysed Lps from control and SAH CSF testing the hypotheses that following brain injury CSF Lps undergo remodelling and apoE containing Lps are selectively depleted from brain injury CSF. Lipoproteins were fractionated using CSF from six control pools and six patients with SAH on a sepharose 6HR 10/30 size exclusion column. Fractions were assayed for total cholesterol (TC), free cholesterol (FC), phospholipid, triglyceride (TG), apoE, apolipoprotein B (apoB), and apolipoprotein AI (apoAI). Compared to control CSF there were significant (P<0.05) increases in TC, FC, TG, and apoAI in SAH CSF. Plasma sized apoB-containing lipoproteins and a very small apoAI-containing Lps were identified in the SAH CSF, which were not present in controls. However, despite the release of plasma lipoproteins into the subarachnoid space, there was no significant increase in CSF apoE. These data provide novel indirect evidence suggesting that after SAH CSF Lps undergo remodelling and apoE containing Lps are selectively reduced in brain injury CSF. The remodelling of CSF Lps and selective reduction of apoE containing lipoproteins may reflect an important response of the human brain to injury.

Toxicity of myoglobin and haemoglobin: oxidative stress in patients with rhabdomyolysis and subarachnoid haemorrhage.

Haemolytic events, such as those following rhabdomyolysis and subarachnoid haemorrhage, often result in pathological complications such as vasoconstriction. Haem-protein cross-linked myoglobin and haemoglobin are generated by ferric-ferryl redox cycling, and thus can be used as markers of oxidative stress. We have found haem-protein cross-linked myoglobin in the urine of patients suffering from rhabdomyolysis and haem-protein cross-linked haemoglobin in the cerebrospinal fluid of patients following subarachnoid haemorrhage. These findings provide strong evidence that these respiratory haem proteins can be involved in powerful oxidation processes in vivo. We have previously proposed that these oxidation processes in rhabdomyolysis include the formation of potent vasoconstrictor molecules, generated by the myoglobin-catalysed oxidation of membranes, inducing nephrotoxicity and renal failure. Haem-protein cross-linked haemoglobin in cerebrospinal fluid suggests that a similar mechanism of lipid oxidation is present and that this may provide a mechanistic basis for the delayed vasospasm that follows subarachnoid haemorrhage.

Spinal cord stimulation--a long-term evaluation in patients with chronic pain.

Spinal cord stimulation (SCS) is an established treatment modality for chronic pain, angina pectoris, and peripheral vascular disease. This study evaluates experience with SCS over a 13-year period with emphasis on surgical complications, revisions and pain relief. It took the form of a retrospective study of medical/surgical records coupled with a postal/telephone questionnaire. The subjects consisted of seventy patients, aged from 21 to 76 years (mean 47; median 46), with severe, chronic pain refractory to conventional treatment, who underwent SCS implantation between 1984 and 1997. It investigated surgical revisions, complications and pain relief. There were 72 surgical revisions comprising electrode replacement/repositioning (32), generator replacement (22), cable failure (6) and implant removal (12). Half the devices were revised within 3 years (95% confidence interval: 2-5 years) of implantation. Six (8.6%) implants became infected. Sixty per cent of patients reported substantial relief of pain. This study shows that the majority of patients undergoing SCS derive significant benefit in terms of pain relief, but commonly require surgical revisions due to both technical and biological factors. These devices require systematic evaluation to determine optimal usage, clinical effectiveness and cost-benefit analysis.

The head injured adult--who cares?

A prospective observational survey of 2957 adults admitted to acute general hospitals in Glasgow after head injury, enabled the features of patients managed in the general hospital 48 hours after head injury to be compared with those transferred to the regional neurosurgical unit and those discharged from hospital.

A clinical audit of the Hakim programmable valve in patients with complex hydrocephalus.

The objective of the investigation was to determine the pattern of use of the Hakim (Medos) programmable valve implanted in patients with complex hydrocephalus and their clinical outcome. A prospective audit of patients with complex hydrocephalus undergoing Hakim programmable valve implantation between 1989 and 1994 in the United Kingdom and Ireland, was followed-up for a minimum of 5 years. Surgical practice and complications were audited together with clinical outcome. One-hundred-and-thirty-nine patients (80 male, 59 female; mean age 43.4 years; median 47 years; range 1 month-84 years) with complex hydrocephalus due to a wide range of aetiologies were implanted with the Hakim programmable valve. Eighty-eight (63%) had large or massive ventricles prior to implantation; seven (5%) were slit. Fifty-five (40%) had previously been shunted with a fixed pressure system. One-hundred-and-thirty-one (94%) of the Hakim programmable shunts were ventriculoperitoneal; four (3%) ventriculoatrial; two (1.4%) cystoperitoneal; and two (1.5%) lumboperitoneal. The initial opening pressure selected ranged from 50 to 200 mmH2O (median 120). Valves were reprogrammed on average 1.7 times with 143 reprogrammings in the first year after implantation; 67 in the second; 19 in the third; three in the fourth; two in the fifth. Forty-nine (36%) valves were never reprogrammed after implantation. During the 5 years audit period, there were 70 (50%) shunt revisions, 40 of which were performed within 1 year of implantation. Thirty-six (27%) shunts were removed. There were 24 (18%) shunt infections. Subdural collections were identified in 37(27%) patients after Hakim programmable valve implantation; 10 (27%) required surgical drainage. Five (3.7%) patients developed symptomatic slit ventricles after Hakim programmable valve implantation. Headache was improved following reprogramming in 27(71%) of the 38 patients with refractory headache. After Hakim programmable valve implantation, patients underwent an average of 4.6 CT scans (range 1-25); 0.3 MRI (range 1-5) and 1.8 skull radiographs (range 1-20). The mean hospital stay per patient over 5 years was 26 days (range 1-110 days). Five years after implantation, the Glasgow Outcome scale was favourable in 64% of patients. The Hakim programmable valve is useful in the management of patients with complex hydrocephalus and may reduce the need for shunt revision for headache. Non-haemorrhagic, post-shunting, subdural collections identified on routine postoperative CT may be treated by reprogramming.

Cerebrospinal fluid monoamine markers are decreased in dementia of the Alzheimer type with extrapyramidal features.

We measured monoamine metabolites and biopterin in the CSF of 37 patients with dementia of the Alzheimer type (DAT), with or without extrapyramidal signs, and in 14 age-matched healthy controls. Compared with concentrations in DAT and controls, the concentrations of homovanillic acid (HVA) and biopterin were significantly decreased in DAT with extrapyramidal signs (EDAT). CSF 3-methoxy-4-hydroxy-phenethyleneglycol and 5-hydroxyindoleacetic acid did not differ significantly among these groups. Age at onset of dementia was positively correlated with CSF HVA (r = 0.49, p less than 0.05). The two dementia groups did not differ significantly in the extent of ventricular dilation as measured by quantitative CT, but EDAT patients had lower Mini-Mental State Examination scores than did DAT patients. When patients were matched for age and dementia severity, CSF HVA and biopterin concentrations remained significantly lower in EDAT than in DAT patients. These results indicate that EDAT patients form a distinct subgroup of DAT with evidence of central monoamine dysfunction.

Cerebrospinal fluid somatostatin and neuropeptide Y. Concentrations in aging and in dementia of the Alzheimer type with and without extrapyramidal signs.

Cerebrospinal fluid somatostatin and neuropeptide Y concentrations were measured in 26 healthy normal subjects, 27 patients with dementia of the Alzheimer type (DAT), and seven patients with DAT with extrapyramidal signs (EDAT). In healthy normal subjects, there was no significant correlation between age and either somatostatin or neuropeptide Y concentration. However, the concentrations of both peptides correlated significantly with each other. In patients with DAT and EDAT, the concentrations of somatostatin (17.5 +/- 5.0 and 16.4 +/- 5.0 pg/mL, respectively) were significantly reduced relative to age-matched control subjects (23.1 +/- 8.2 pg/mL) but were unrelated to dementia severity and did not change significantly during the progression of the disease. Neuropeptide Y concentrations did not differ significantly between the age-matched control, DAT, and EDAT groups (38.2 +/- 12.8, 37.0 +/- 12.3, and 30.3 +/- 7.8 pg/mL, respectively). These results suggest that in DAT, dysfunction of cortical somatostatin but not neuropeptide Y transmitter systems is reflected by reduced cerebrospinal fluid concentrations.

Cerebrospinal fluid cholinesterases in aging and in dementia of the Alzheimer type.

Protein concentration and acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities were assayed in the cerebrospinal fluid (CSF) of 26 healthy normal subjects (20-86 years old), 27 patients with dementia of the Alzheimer type (DAT), and 10 patients with dementia of the Alzheimer type with extrapyramidal signs (EDAT). In normal subjects, there was an age-related increase in CSF protein and AChE activity and a significant correlation (p less than 0.001) between CSF protein and BChE activity. In the DAT and EDAT groups, CSF AChE activities (mean +/- SD = 17.5 +/- 3.6 and 15.3 +/- 4.4 nmol/min/ml, respectively) were significantly lower (p less than 0.05) than in 13 age-matched control subjects (21.5 +/- 5.6 nmol/min/ml). In contrast, neither CSF protein concentration, BChE activity, nor the ratio of AChE/BChE differed significantly between groups. In patients with DAT, CSF AChE activity was significantly lower (p less than 0.05) in subjects with an early onset compared to those with a late onset (16.4 +/- 3.4 and 19.7 +/- 2.8 nmol/min/ml, respectively), and activity in the latter group did not differ significantly from control values. CSF AChE activity was not related to dementia severity and did not change significantly over an 18-month period. Although these results confirm a cholinergic deficit in patients with DAT, the considerable overlap of CSF AChE activity between groups and the nonsignificant correlation between AChE activity and dementia severity limit the usefulness of CSF AChE as a diagnostic marker of this disorder.

Cerebrospinal fluid monoamines in Down's syndrome adults at different ages.

Markers of monoamine metabolism in lumbar cerebrospinal fluid (CSF) and plasma were determined in nine young, healthy adults with trisomy 21 Down's syndrome (DS), 21-34-years-old, and in three DS subjects over 45 years, two of whom were demented, as well as in two groups of age-matched controls. Test scores of general intelligence, visuospatial ability, visual discrimination and verbal intelligence were reduced significantly in the old as compared to the young DS subjects. Dementia in DS was evident from a history of mental deterioration, disorientation and hallucinations. In the young DS adults, as compared to the controls, CSF 5-HIAA and norepinephrine were significantly elevated but plasma levels were unchanged. HVA, MHPG and biopterin did not differ between the DS groups and age-matched controls, or with relation to age in the DS or control subjects. These results suggest an increased turnover of monoamines in young adults with DS but that alterations in monoamine metabolism are unrelated to the cognitive decline with age in DS.

Urethral pressure profilometry in mares.

A technique was developed for recording urethral pressure profiles (UPP) in mares. Profiles were obtained from 12 clinically normal mares and from 3 mares with urinary incontinence. Variables measured on the profile included intravesicular pressure and maximal urethral closure pressure. The mean maximal urethral closure pressure of the incontinent mares was significantly less (P less than or equal to 0.001) than that of the normal mares. The technique is simple and reliable for objectively evaluating urethral pressures in mares.