Effect of exercise on pain processing and motor output in people with knee osteoarthritis: a systematic review and meta-analysis

OBJECTIVE

Guidelines recommend exercise as a core treatment for knee osteoarthritis. However, it is unclear how exercise affects measures of pain processing and motor function. The aim was to evaluate the effect of exercise on measures of pain processing and motor function in people with knee osteoarthritis.

METHODS

We searched five electronic databases (MEDLINE, EMBASE, CINAHL, SCOPUS and Cochrane Central Register of Controlled Trials) for studies on knee osteoarthritis, of any design, evaluating pain processing and motor function before and after exercise. Data were pooled with random-effects meta-analysis. Study quality was assessed using the Downs and Black and quality of evidence was assessed using the GRADE.

RESULTS

Eighteen studies were eligible and 16 were included. Following acute exercise, pressure pain threshold increased local to the study limb (standardised mean difference [95% confidence interval (CI)] 0.26, [0.02, 0.51], n = 159 from 5 studies), but there was no statistically significant change remote from the study limb (0.09, [-0.11, 0.29], n = 90 from 4 studies). Following an exercise program (range 5-12 weeks) there were no statistically significant changes in pressure pain threshold (local 0.23, [-0.01, 0.47], n = 218 from 8 studies; remote 0.33 [-0.13, 0.79], n = 76 from 4 studies), temporal pain summation (0.38 [-0.08, 0.85], n = 122 from 3 studies) or voluntary quadriceps muscle activation (4.23% [-1.84 to 10.30], n = 139 from 4 studies).

CONCLUSION

Very-low quality evidence suggests that pressure pain threshold increases following acute exercise. Very-low quality evidence suggests that pressure pain threshold, temporal pain summation or voluntary quadriceps activation do not change statistically significantly following exercise programs.

Neuroendocrine and endocrine dysfunction in the hyperinsulinemic PCOS patient: the role of metformin

Metformin is a widely used and extensively studied insulin sensitising drug for the treatment of women with polycystic ovary syndrome (PCOS), with various actions in tissues responding to insulin that include the liver, skeletal muscle, adipose tissue, the endothelium of blood vessels, and the ovaries. Treatment of PCOS women with metformin has been shown to reduce fasting glucose levels, blood pressure, and serum androgens; further effects of metformin in women with PCOS may include direct effects on the central nervous system; and indirect effects via the modification of gut hormone and adipokine synthesis and/or secretion. A number of "novel" adipokines and metabolic factors have been recently identified which may play a role both in the pathogenesis and the treatment of women with PCOS. We here discuss recent advances in the area, with a focus on neuroendocrine and endocrine dysfunctions in women with PCOS and the potential role of metformin in this context.

Myoelectric manifestations of fatigue in vastus lateralis, medialis obliquus and medialis longus muscles

The purpose of this study was to determine whether surface electromyography (EMG) assessment of myoelectric manifestations of muscle fatigue is capable of detecting differences between the vastus lateralis and medialis muscles which are consistent with the results of previous biopsy studies. Surface EMG signals were recorded from the vastus medialis longus (VML), vastus medialis obliquus (VMO) and vastus lateralis (VL) muscles during isometric knee extension contractions at 60% and 80% of the maximum voluntary contraction (MVC) for 10s and 60s, respectively. Initial values and rate of change of mean frequency (MNF), average rectified value (ARV) and conduction velocity (CV) of the EMG signal were calculated. Comparisons between the two force levels revealed that the initial values of MNF for the VL muscle were greater at 80% MVC compared to 60% MVC (P<0.01). Comparisons between the vasti muscles demonstrated lower initial values of CV for VMO compared to VL at 60% MVC (P<0.01) and lower than VML and VL at 80% MVC (P<0.01). In addition, initial values of MNF were higher for VL with respect to both VML and VMO at 80% MVC (P<0.01) and initial estimates of ARV were higher for VMO compared to VML at both force levels (P<0.01 at 60% MVC and P<0.05 at 80% MVC). For the sustained contraction at 80% MVC, VL demonstrated a greater decrease in CV over time compared to VMO (P<0.05). These findings suggest that surface EMG signals and their time course during sustained isometric contractions may be useful to non-invasively describe functional differences between the vasti muscles.

An endurance-strength training regime is effective in reducing myoelectric manifestations of cervical flexor muscle fatigue in females with chronic neck pain

OBJECTIVE

The purpose of this study was to investigate whether an endurance-strength training program is effective in reducing myoelectric manifestations of sternocleidomastoid (SCM) and anterior scalene (AS) muscle fatigue which have been found to be greater in people with chronic neck pain.

METHODS

Fifty-eight female patients with chronic non-severe neck pain were randomized into one of two 6-week exercise intervention groups: an endurance-strength training regime for the cervical flexor muscles or a referent exercise intervention involving low load retraining of the cranio-cervical flexor muscles. The primary outcomes were a change in maximum voluntary contraction (MVC) force and change of the initial value and rate of change of the mean frequency, average rectified value and conduction velocity detected from the SCM and AS muscles during sub-maximal isometric cervical flexion contractions at 50, 25 and 10% MVC.

RESULTS

At the 7th week follow-up assessment, the endurance-strength training group revealed a significant increase in MVC force and a reduction in the estimates of the initial value and rate of change of the mean frequency for both the SCM and AS muscles (P<0.05). Both exercise groups reported a reduced average intensity of neck pain and reduced neck disability index score (P<0.05).

CONCLUSIONS

An endurance-strength exercise regime for the cervical flexor muscles is effective in reducing myoelectric manifestations of superficial cervical flexor muscle fatigue as well as increasing cervical flexion strength in a group of patients with chronic non-severe neck pain.

SIGNIFICANCE

Provision of load to challenge the neck flexor muscles is required to reduce the fatigability of the SCM and AS muscles in people with neck pain. Improvements in cervical muscle strength and reduced fatigability may be responsible for the reported efficacy with this type of exercise program.

Preparatory trunk motion accompanies rapid upper limb movement

Evaluation of trunk movements, trunk muscle activation, intra-abdominal pressure and displacement of centres of pressure and mass was undertaken to determine whether trunk orientation is a controlled variable prior to and during rapid bilateral movement of the upper limbs. Standing subjects performed rapid bilateral symmetrical upper limb movements in three directions (flexion, abduction and extension). The results indicated a small (0.4-3.3 degrees) but consistent initial angular displacement between the segments of the trunk in a direction opposite to that produced by the reactive moments resulting from limb movement. Phasic activation of superficial trunk muscles was consistent with this pattern of preparatory motion and with the direction of motion of the centre of mass. In contrast, activation of the deep abdominal muscles was independent of the direction of limb motion, suggesting a non-direction specific contribution to spinal stability. The results support the opinion that feedforward postural responses result in trunk movements, and that orientation of the trunk and centre of mass are both controlled variables in relation to rapid limb movements.

Moving psychiatric patients from hospital to community: views of patients, providers, and families

OBJECTIVE

Differences in the perspectives of severely and persistently ill patients, their family members, and clinical care providers on key aspects of community-based care were examined to help inform community service planning and development.

METHODS

A sample of 183 patients being considered for relocation from psychiatric facilities in Alberta, Canada, to community-based care, were interviewed, as were their primary clinical care providers. Family members of 130 patients were also interviewed.

RESULTS

Among the 130 patient-family pairs, 41 percent disagreed about the desirability of relocation, with fewer patients favoring relocation than families. Forty-nine percent of the pairs disagreed about the desired proximity to the family of the relocated patient, with the patient desiring closer proximity than the family member in about half of these cases. Fifty-three percent of the pairs disagreed about the amount of financial and emotional support that the family would provide after relocation. In half of these cases, patients believed the family would provide a higher level of support than the family indicated it could. Among the patients, 49 percent preferred independent living, whereas only 10 percent of family members and 17 percent of clinical care providers preferred it. Fifty-five percent of patients expressed a clear desire to work, whereas care providers believed that only 12 percent of patients were employable.

CONCLUSIONS

Persistently mentally ill residents of psychiatric facilities express clear preferences about key aspects of community-based care when they are asked, and these preferences often reflect different views from those expressed by either family members or clinical care providers.

Potential for community relocation among residents of Alberta's psychiatric facilities: a needs assessment

OBJECTIVE

To identify the proportion of residents in Alberta's psychiatric hospitals who would be relocatable to community-based alternatives to care if appropriate programs were made available.

METHODS

A Survey of a representative sample of residents in all psychiatric hospitals and care centres was undertaken, excluding patients in specialized programs for forensic psychiatry, brain injury, and substance abuse.

RESULTS

Findings indicate that 11% of institutionalized patients could be considered good candidates for relocation to community-based alternative care. A further 35% were considered to have potential for relocation provided an intensive and complex array of services was first made available.

CONCLUSION

Results support a phased-in approach to hospital downsizing and the need for considerable transitional funding. Because hospital downsizing is unlikely to save dollars, at least in the short term, reforms must remain guided by humanitarian motivations to improve quality of life for persons with severe and persistent mental illnesses.

What's up, Billy Jo? Deaf children and bilingual-bicultural instruction in east-central Texas

Seven deaf children attended a bilingual-bicultural (bi-bi) prekindergarten, kindergarten, and first grade from 1993 to 1996 in an east-central Texas public school. The children had diverse backgrounds (African American, Hispanic, White) and various intellectual, cognitive, and linguistic abilities. We detail the backgrounds of the seven children and their families and describe three bi-bi classrooms. We present standardized test scores on cognition (Bracken Test of Basic Concepts) and academic achievement (Stanford Achievement Test, 9th edition, and Woodcock-Johnson Psycho-Educational Battery). When, with one exception, the children completed first grade, they all tested at grade level. (The exception was a younger child who had only completed kindergarten but who nonetheless tested at the first-grade level). We interpret our findings in light of theories of first- and second-language acquisition and discuss the feasibility of establishing bi-bi programs in areas where no large Deaf community exists. We also note our plans to evaluate the seven children again, at the end of second grade in spring 1997.

Evaluation of the relationship between laboratory and clinical tests of transversus abdominis function

A clinical test of the function of the deep abdominal muscles was compared to a laboratory electromyographic (EMG) investigation of the contribution of transversus abdominis (TrA) to stability of the lumbar spine during limb movement. The two different functions of TrA were evaluated in 15 subjects. The subject group included six subjects with chronic low back pain and nine subjects with no history of low back pain so that the resultant recordings were spread over a wide range for each test. The clinical test involved quantification of the ability of the subjects to specifically displace the anterior abdominal wall in a way consistent with the function of the muscle. This was evaluated by use of a device designed to measure pressure reduction as the abdomen lifted off a transducer in the prone position. The laboratory test involved determination of the onset of contraction of TrA associated with rapid upper limb movement, measured using fine-wire EMG electrodes. The parameter evaluated was the latency between the contraction of TrA and the prime mover of the limb. Data were analysed both as absolute values and as ordinal data of a three-rating scale derived from criteria based on current knowledge of the response to both tests. No significant correlation was found between the absolute magnitudes of the pressure and timing data, however, comparison of the rating scale data indicated a significant relationship between the tests and associated high level of agreement between the two measures. The results of the study indicate that a reduction in the ability to draw in the abdominal wall is related to changes in the coordination of TrA, although the magnitude of the changes were not correlated. The degree of causality between these co-varying but independent manifestations of the function of TrA is uncertain.

Apolipoprotein B mRNA editing: a new tier for the control of gene expression

Two forms of apolipoprotein (apo) B are found in mammals. The shorter form is translated from an edited mRNA in which a specific cytidine base is deaminated to a uridine, creating a new stop codon. Apo B mRNA editing is mediated by a site-specific cytidine deaminase that recognizes a downstream target sequence in the RNA. The enzyme has no energy or cofactor requirements and no RNA component, and thus bears no obvious relationship to RNA processing events such as splicing or polyadenylation. While apo B mRNA editing activity may have arrived late in evolution to target dietary lipid to the liver in mammals, the discovery of the editing activity in tissues and cells that do not express apo B suggests a more widespread role in the generation of RNA and protein diversity.

Nuclear protein synthesis in animal and vegetal hemispheres of Xenopus oocytes

Experiments were conducted to determine if nuclear proteins are preferentially synthesized in the vicinity of the nucleus, a factor which could facilitate nucleocytoplasmic exchange. Using Xenopus oocytes, animal and vegetal hemispheres were separated by bisecting the cells in paraffin oil. It was initially established that protein synthesis is not affected by the bisecting procedure. To determine if nuclear protein synthesis is restricted to the animal hemisphere (which contains the nucleus), vegetal halves and enucleated animal halves were injected with [3H]leucine and incubated in oil for 90 min. The labeled cell halves were then fused with unlabeled, nucleated animal hemispheres that had been previously injected with puromycin in amounts sufficient to prevent further protein synthesis. Thus, labeled polypeptides which subsequently entered the nuclei were synthesized before fusion. Three hours after fusion, the nuclei were isolated, run on two-dimensional gels, and fluorographed. Approximately 200 labeled nuclear polypeptides were compared, and only 2 were synthesized in significantly different amounts in the animal and vegetal hemispheres. The results indicate that nuclear protein synthesis is not restricted to the cytoplasm adjacent to the nucleus.

Cross-resistance to intercalating agents in an epipodophyllotoxin-resistant Chinese hamster ovary cell line: evidence for a common intracellular target

Several intercalating agents, as well as the epipodophyllotoxins, appear to effect DNA damage through their interaction with type II DNA topoisomerases. However, the relationship of this phenomenon to anti-tumor activity remains unproven. Our studies with an epipodophyllotoxin-resistant cell line not only provide additional evidence that the enzyme is a multidrug target but also serve to implicate it as a mediator of cytotoxic effect. When compared to wild-type cells, the epipodophyllotoxin-resistant Chinese hamster ovary cell line, VpmR-5, exhibits cross-resistance to both the cytotoxic and DNA cleavage activities of 4',9-acridinylaminomethanesulfon-m-anisidide, mitoxantrone, and Adriamycin. Steady-state concentrations of radiolabeled-4',9-acridinylaminomethanesulfon-m-anisidide and daunomycin are identical in both cell lines. Sharp plateaus in the VpmR-5 dose-response curves for Adriamycin-induced DNA strand breaks and cytotoxicity appear to be related to interference with type II topoisomerase-mediated cleavage of DNA at high concentrations of the intercalator. These data support a direct role for DNA strand scission in cell death and also suggest that multidrug resistance may be acquired by a qualitative change in type II topoisomerase that alters interaction of drug with the enzyme or enzyme-DNA complex.

Protein-energy intake and malnutrition in Crohn's disease

A detailed nutrient assessment was made of 23 male and 24 female patients with Crohn's disease who entered sequentially into an outpatient clinic. Assessment included 48-hour dietary recall, anthropometric measurements, and biochemical and hematological tests appropriate to characterize protein-energy malnutrition. Approximately 40% of patients had energy intakes equal to only two-thirds of the Recommended Dietary Allowance (RDA). Three men and five women had relative body weights less than 85% of standard, but body weight was not correlated with energy intake. Relative body weight was correlated with arm muscle circumference in both male and female patients and with triceps skinfold and total lymphocyte count in women. Although the mean protein intake was greater than 150% of the RDA, evidence of protein malnutrition included low arm muscle circumference in 14% of the men and 15% of the women, low serum albumin concentration in 13% of the women, and low total lymphocyte count in one-half of the patients. The Crohn's disease activity index was correlated significantly with serum albumin, energy intake, and duration of disease in men and with serum ferritin and hemoglobin concentration in women. Thus, a reduced relative body weight or reduced serum albumin was not uncommon in patients with Crohn's disease but did not necessarily occur in those with reduced intakes of protein and energy. However, a low relative body weight may indicate need for further nutritional assessment.

Nutrient intake of patients with cystic fibrosis

Nutrient intake, anthropometric measurements, and pulmonary function were assessed in 26 young adult patients with cystic fibrosis (CF). Mean nutrient intakes, excluding those from vitamins and nutrient supplements, were less than the Recommended Dietary Allowances for folate for men and women and for iron and vitamin B-6 for women. Male cystic fibrosis patients consumed significantly more of 11 of 16 nutrients in comparison with men with Crohn's disease and men with functional gastrointestinal complaints. Female cystic fibrosis patients consumed significantly more of 9 of 16 nutrients than did women with gastrointestinal complaints. The relative body weight was less than 85% of standard in 65% of men and 50% of women with CF. Relative body weight was correlated with variables indicative of airflow obstruction, reduced vital capacity, and hyperinflation of lung volumes.

Vitamin and iron intake in patients with Crohn's disease

A descriptive study was conducted in 23 male and 24 female adult patients with Crohn's disease to assess nutritional status. The mean daily intake of vitamin B6 and folate by the men and the women and of iron by the women was less than the Recommended Dietary Allowances. However, the range of individual intakes varied widely. According to Nutrition Canada Interpretive Standards, 50% of the female patients had inadequate intakes of iron; 13%, of riboflavin; 21%, of thiamin; and 21%, of vitamin A. The men consumed significantly less vitamin A and folate per 1,000 kcal than the women. Serum folate was the only laboratory parameter that correlated with nutrient intake; it was correlated with dietary folate, vitamin C, vitamin B12, and vitamin B6 intakes in the women only. Serum folate was low in 21% of the men and 26% of the women. Thus, a low serum folate was predictive of a potential risk of nutritional deficiency of folate and of vitamins B6, B12, and C. This study demonstrated that nutrient intake was reduced in some patients and therefore could be a factor contributing to observed nutritional deficiency in Crohn's disease.

Chromatography of transforming deoxyribonucleic acid on methylated albumin and by gel filtration

1. Native DNA from two strains of Bacillus subtilis was chromatographed by stepwise elution from MAK (methylated albumin on kieselguhr). 2. Transforming activity was confined to two out of the three main fractions, activity being distributed between the two peaks differently for DNA from the different strains. 3. Fractionation of DNA from both strains on 2% agarose gel gave two components. Approx. 75% of the material was eluted within the void volume of the column. Approx. 25% of the material consisted of degradation products of lower molecular weight. 4. Chromatography on MAK of the material of high molecular weight eluted from agarose gel gave a number of peaks differing in molecular weight, indicating that degradation of the DNA takes place during chromatography on MAK. 5. The distribution of transforming activity among the fractions from MAK suggests that degradation occurs preferentially in certain regions of the DNA.