Assessment of Potentially Inappropriate Prescribing for People With Type 2 Diabetes Mellitus Using IMPACT2DM, a New Explicit Tool

Background: People with type 2 diabetes mellitus (T2DM) are at greater risk of potentially inappropriate prescribing (PIP) due to multiple comorbidities and polypharmacy. IMPACT2DM (Inappropriate Medication Prescribing Assessment Criteria for Type 2 Diabetes Mellitus) is a tool designed to identify PIP for adults with T2DM. Objectives: To assess PIP for adults with T2DM in Ethiopia using the IMPACT2DM and to test the face validity and clinical validity of the tool. Methods: A cross-sectional study was undertaken using data extracted retrospectively from the medical records of adults being managed for T2DM at Debretabore Hospital. PIP was assessed using IMPACT2DM. Some items/item components of IMPACT2DM were modified to increase the tool's applicability for the outpatient setting, to clarify content or to use the terms most common in this particular setting. Multivariant logistic regression analyses were conducted to identify factors associated with PIP. Results: More than 90% of medical records had at least 1 PIP. Prescribing omission (80.9%) was the most commonly identified type of PIP. Adults with prescribing omissions are more likely to be ≥40 years old or to be prescribed with <5 medications. Adults with dosing problems were more likely ≥50 years old, or have had a fasting blood sugar (FBS) level out of the target range (80-130 mg/dL). Conclusions: IMPACT2DM is a clinically valid PIP identification tool for application in an Ethiopian outpatient setting. Health professionals should be alert to check for potential prescribing omissions for adults ≥40 years old and dosing problems for adults with an FBS level out of the target range or >50 years.

Effect of exercise training on the renin-angiotensin-aldosterone system: a meta-analysis

Blood pressure (BP) management reduces the risk of cardiovascular disease (CVD). The renin-angiotensin-aldosterone system (RAAS) plays an important role in regulating and maintaining blood volume and pressure. This analysis aimed to investigate the effect of exercise training on plasma renin, angiotensin-II and aldosterone, epinephrine, norepinephrine, urinary sodium and potassium, BP and heart rate (HR). We systematically searched PubMed, Web of Science, and the Cochrane Library of Controlled Trials until 30 November 2022. The search strategy included RAAS key words in combination with exercise training terms and medical subject headings. Manual searching of reference lists from systematic reviews and eligible studies completed the search. A random effects meta-analysis model was used. Eighteen trials with a total of 803 participants were included. After exercise training, plasma angiotensin-II (SMD -0.71; 95% CI -1.24, -0.19; p = 0.008; n = 9 trials), aldosterone (SMD -0.37; 95% CI -0.65, -0.09; p = 0.009; n = 8 trials) and norepinephrine (SMD -0.82; 95% CI -1.18, -0.46; p < 0.001; n = 8 trials) were reduced. However, plasma renin activity, epinephrine, and 24-h urinary sodium and potassium excretion remained unchanged with exercise training. Systolic BP was reduced (MD -6.2 mmHg; 95% CI -9.9, -2.6; p = 0.001) as was diastolic BP (MD -4.5 mmHg; 95% CI -6.9, -2.1; p < 0.001) but not HR (MD -3.0 bpm; 95% CI -6.0, 0.4; p = 0.053). Exercise training may reduce some aspects of RAAS and sympathetic nervous system activity, and this explains some of the anti-hypertensive response.

Isometric Resistance Training to Manage Hypertension: Systematic Review and Meta-analysis

PURPOSE OF REVIEW

Hypertension is the primary risk factor for cardiovascular disease and adequate blood pressure control is often elusive. The objective of this work was to conduct a meta-analysis of trial data of isometric resistance training (IRT) studies in people with hypertension, to establish if IRT produced an anti-hypertensive effect. A database search (PubMed, CINAHL, Cochrane Central Register of Controlled Trials, and MEDLINE) identified randomised controlled and crossover trials of IRT versus a sedentary or sham control group in adults with hypertension.

RECENT FINDINGS

We included 12 studies (14 intervention groups) in the meta-analyses, with an aggregate of 415 participants. IRT reduced systolic blood pressure (SBP), mean difference (MD) - 7.47 mmHg (95%CI - 10.10, - 4.84), P < 0.01; diastolic blood pressure (DBP) MD - 3.17 mmHg (95%CI - 5.29, - 1.04), P < 0.01; and mean arterial blood pressure (MAP) MD - 7.19 mmHg (95%CI - 9.06, - 5.32), P < 0.0001. Office pulse pressure and resting heart rate was not significantly reduced, neither were 24-h or day-time ambulatory blood pressures (SBP, DBP). Night-time blood pressures, however, were significantly reduced with SBP MD - 4.28 mmHg (95%CI - 7.88, - 0.67), P = 0.02, and DBP MD - 2.22 mmHg (95%CI - 3.55, - 0.88), P < 0.01. IRT does lower SBP, DBP and MAP office and night-time ambulatory SBP and DBP, but not 24-h mean ambulatory blood pressures in people with hypertension.

An evidence-based guide to the efficacy and safety of isometric resistance training in hypertension and clinical implications

More than 30 randomized controlled trials, supported by individual patient-level and group-level meta-analyses and a Delphi analysis of expert opinion, unequivocally show isometric resistance training (IRT) elicits antihypertensive benefits in healthy people and those with chronic illness. We aim to provide efficacy and safety evidence, and a guide for IRT prescription and delivery. Recommendations are made for the use of IRT in specific patient populations and appropriate methods for IRT delivery. Published data suggest IRT consistently elicits mean blood pressure reductions of 7.4/3.3 mmHg systolic blood pressure/diastolic blood pressure, equivalent to antihypertensive medication monotherapy. Blood pressure reductions of this size are associated with an approximate 13% to 22% reduction in major cardiovascular events. Moreover, IRT is safe in a range of patient populations. We suggest that IRT has the greatest potential benefit when used as an antihypertensive therapy in individuals unwilling and/or unable to complete aerobic exercise, or who have had limited adherence or success with it; individuals with resistant or uncontrolled hypertension, already taking at least two pharmacological antihypertensive agents; and healthy or clinical populations, as an adjunct to aerobic exercise and dietary intervention in those who have not yet attained control of their hypertension. IRT is efficacious and produces clinically meaningful blood pressure reductions (systolic blood pressure, 7 mmHg; diastolic blood pressure, 3 mmHg). IRT is safe and typical program delivery requires only about 17 min weekly. IRT should be used as an adjunct to other exercise modalities, in people unable to complete other types of exercise, or in resistant hypertension.

Safety, efficacy and delivery of isometric resistance training as an adjunct therapy for blood pressure control: a modified Delphi study

Uncontrolled hypertension remains the major risk factor for cardiovascular disease. Isometric resistance training (IRT) has been shown to be a useful nonpharmacological therapy for reducing blood pressure (BP); however, some exercise physiologists and other health professionals are uncertain of the efficacy and safety of IRT. Experts' consensus was sought in light of the current variability of IRT use as an adjunct treatment for hypertension. An expert consensus-building analysis (Delphi study) was conducted on items relevant to the safety, efficacy and delivery of IRT. The study consisted of 3 phases: (1) identification of items and expert participants for inclusion; (2) a two-round modified Delphi exercise involving expert panelists to build consensus; and (3) a study team consensus meeting for a final item review. A list of 50 items was generated, and 42 international experts were invited to join the Delphi panel. Thirteen and 10 experts completed Delphi Rounds 1 and 2, respectively, reaching consensus on 26 items in Round 1 and 10 items in Round 2. The study team consensus meeting conducted a final item review and considered the remaining 14 items for the content list. A final list of 43 items regarding IRT reached expert consensus: 7/10 items on safety, 11/11 items on efficacy, 10/12 items on programming, 8/10 items on delivery, and 7/7 on the mechanism of action. This study highlights that while experts reached a consensus that IRT is efficacious as an antihypertensive therapy, some still have safety concerns, and there is also ongoing conjecture regarding optimal delivery.

Potentially inappropriate prescribing for adults living with diabetes mellitus: a scoping review

BACKGROUND

People living with diabetes often experience multiple morbidity and polypharmacy, increasing their risk of potentially inappropriate prescribing. Inappropriate prescribing is associated with poorer health outcomes.

AIM

The aim of this scoping review was to explore and map studies conducted on potentially inappropriate prescribing among adults living with diabetes and to identify gaps regarding identification and assessment of potentially inappropriate prescribing in this group.

METHOD

Studies that reported any type of potentially inappropriate prescribing were included. Studies conducted on people aged < 18 years or with a diagnosis of gestational diabetes or prediabetes were excluded. No restrictions to language, study design, publication status, geographic area, or clinical setting were applied in selecting the studies. Articles were systematically searched from 11 databases.

RESULTS

Of the 190 included studies, the majority (63.7%) were conducted in high-income countries. None of the studies used an explicit tool specifically designed to identify potentially inappropriate prescribing among people with diabetes. The most frequently studied potentially inappropriate prescribing in high-income countries was contraindication while in low- and middle-income countries prescribing omission was the most common. Software and websites were mostly used for identifying drug-drug interactions. The specific events and conditions that were considered as inappropriate were inconsistent across studies.

CONCLUSION

Contraindications, prescribing omissions and dosing problems were the most commonly studied types of potentially inappropriate prescribing. Prescribers should carefully consider the individual prescribing recommendations of medications. Future studies focusing on the development of explicit tools to identify potentially inappropriate prescribing for adults living with diabetes are needed.

Development and validation of explicit criteria to identify potentially inappropriate prescribing for adults with type 2 diabetes mellitus

BACKGROUND

Early detection and timely resolution of potentially inappropriate prescribing (PIP) prevents adverse outcomes and improves patient care. An explicit tool specifically designed to detect PIP among people with Type 2 Diabetes Mellitus (T2DM) has not been published.

OBJECTIVES

This study aims to develop and validate the Inappropriate Medication Prescribing Assessment Criteria for Type 2 Diabetes Mellitus (IMPACT2DM); an explicit tool that can be used to identify PIP for adults with T2DM.

METHODS

Current national and international guidelines for the management of T2DM and drug information software programs were used to generate potential items. The content of the IMPACT2DM was validated by 2 consecutive rounds of Delphi method. Physicians and clinical pharmacists experienced in providing care for people with diabetes and authors of selected diabetes guidelines were invited to participate in the Delphi panel. Consensus was assumed if 90% (first round) and 85% (second round) of expert panelists showed agreement to include or exclude an item.

RESULTS

A total of 95 potential items were generated from selected diabetes guidelines and drug information software programs. After the first Delphi round 27 items had ≥90% agreement and were included in the tool; 19 items were considered not PIP and were excluded from the tool. The second round contained 49 items; of these 43 were included and 6 were excluded from the tool. The final IMPACT2DM contains 70 items categorized by type of PIP and arranged in terms of medical conditions and medication classes. IMPACT2DM can be applied using information on medical charts and requires minimal or no clinical knowledge to assess quality of diabetes care and improve medication selection.

CONCLUSIONS

IMPACT2DM has been developed from current quality evidence and undergone content validation. It is the first explicit tool specifically designed to identify PIP for adults with T2DM.

The effect of remote ischaemic conditioning on blood pressure response: A systematic review and meta-analysis

BACKGROUND

Previous work has evaluated the effect of remote ischaemic conditioning (RIC) in a number of clinical conditions (e.g. cardiac surgery and acute kidney injury), but only one analysis has examined blood pressure (BP) changes. While individual studies have reported the effects of acute bouts and repeated RIC exposure on resting BP, efficacy is equivocal. We conducted a systematic review and meta-analysis to evaluate the effects of acute and repeat RIC on BP.

METHODS

A systematic search was performed using PubMed, Web of Science, EMBASE, and Cochrane Library of Controlled Trials up until October 31, 2020. Additionally, manual searches of reference lists were performed. Studies that compared BP responses after exposing participants to either an acute bout or repeated cycles of RIC with a minimum one-week intervention period were considered.

RESULTS

Eighteen studies were included in this systematic review, ten examined acute effects while eight investigated repeat effects of RIC. Mean differences (MD) for outcome measures from acute RIC studies were: systolic BP 0.18 mmHg (95%CI -0.95, 1.31; p = 0.76), diastolic BP -0.43 mmHg (95%CI -2.36, 1.50; p = 0.66), MAP -1.73 mmHg (95%CI -3.11, -0.34; p = 0.01) and HR -1.15 bpm (95%CI -2.92, 0.62; p = 0.20). Only MAP was significantly reduced. Repeat RIC exposure showed non-significant change in systolic BP -3.23 mmHg (95%CI -6.57, 0.11; p = 0.06) and HR -0.16 bpm (95%CI -7.08, 6.77; p = 0.96) while diastolic BP -2.94 mmHg (95%CI -4.08, -1.79; p < 0.00001) and MAP -3.21 mmHg (95%CI -4.82, -1.61; p < 0.0001) were significantly reduced.

CONCLUSIONS

Our data suggests repeated, but not acute, RIC produced clinically meaningful reductions in diastolic BP and MAP.

Effect of Age on Clinical Outcomes Following On-/Off-Pump Coronary Artery Bypass: Meta-Analysis and Meta-Regression

Objective

There is currently much debate about which patients would benefit more after on- or off-pump coronary artery bypass grafting (CABG). The aim of this meta-analysis and meta-regression is to investigate the effect of age on short-term clinical outcomes after these approaches.

Methods

To identify potential studies, systematic searches were carried out in the Excerpta Medica dataBASE (EMBASE), PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials (CENTRAL). The search strategy included the key concepts of “cardiopulmonary bypass” AND “coronary artery bypass grafting” AND “off pump” OR “on pump”. This was followed by a meta-analysis and meta-regression investigating the effect of age on the incidences of stroke, myocardial infarction (MI), and mortality.

Results

Thirty-seven studies including 15,324 participants were analysed. Overall, there was a significant odds reduction for patients receiving off-pump CABG suffering a stroke (odds ratio [OR] 0.770, 95% confidence intervals [CI] 0.594, 0.998, P=0.048); however, when patients were subdivided according to different age bands, this difference disappeared. There were also no significant differences in the odds of mortality (OR 0.876, 95% CI 0.703, 1.093, P=0.241) or MI (OR 0.937, 95% CI 0.795, 1.105, P=0.439). Meta-regression analysis revealed no significant relationship between age and stroke (P=0.652), age and mortality (P=548), and age and MI (P=0.464).

Conclusion

Patients undergoing CABG are becoming older and may suffer from multiple comorbidities increasing their risk profile. However, with respect to short-term clinical outcomes, the patient’s age does not help in determining whether off- or on-pump is superior.

Potentially inappropriate prescribing for adults with diabetes mellitus: a scoping review protocol

OBJECTIVE

This scoping review aims to explore and map studies investigating potentially inappropriate prescribing (PIP) for adults with diabetes mellitus.

INTRODUCTION

Inappropriate prescribing for people with diabetes mellitus has been reported by various authors focusing on different aspects of inappropriateness. A preliminary search revealed no published reviews on PIP for adults with diabetes mellitus. As a result, it is difficult to obtain a comprehensive map of PIP in this patient group.

INCLUSION CRITERIA

This scoping review will consider all studies on PIP for adults with the diagnosis of type 1 or type 2 diabetes mellitus from any clinical setting. Studies conducted in pediatric populations or in adults with pre-diabetes or gestational diabetes will be excluded.

METHODS

A three-step search strategy (i.e. an initial limited search in PubMed and ProQuest Central databases, a main search of eight databases and gray literature, and manual searches of reference lists of included articles) will be utilized. No language restrictions will be applied. All retrieved articles will be screened against the inclusion/exclusion criteria at title, abstract, and full-text stages. Data to be extracted from each study will include, but not be limited to, country, objective, study population, study methodology, type of PIP studied, examples of PIP events, medications involved, and criteria used for PIP identification. Data will be extracted by study team members using an online application for conducting systematic synthesis of evidence.

Effect of vitamin D supplementation on endothelial function - An updated systematic review with meta-analysis and meta-regression

BACKGROUND AND AIMS

Atherogenesis and endothelial dysfunction contribute to cardiovascular risk and vitamin D has been implemented in endothelial repair. This systematic review, meta-analysis and meta-regression aims to establish the effect of vitamin D supplementation on endothelial function.

METHODS AND RESULTS

To conduct the systematic review we searched the Cochrane Library of Controlled Trials, PubMed, ProQuest and EMBASE for randomized controlled trials that investigated the effects of vitamin D supplementation on flow-mediated dilation (FMD%), pulse wave velocity (PWV), and central augmentation index (AIx). Meta-analysis was based on a random effects model and inverse-variance methods to calculate either mean difference (MD) or standardized mean difference (SMD) as effects sizes. This was followed by meta-regression investigating the effect of baseline vitamin D concentrations, vitamin D dosing and study duration. Risk of bias was assessed using the JADAD scale and funnel plots. We identified 1056 studies of which 26 studies met inclusion criteria for quantitative analysis. Forty-two percent of the 2808 participants had either deficient or insufficient levels of vitamin D. FMD% (MD 1.17% (95% CI -0.20, 2.54), p = 0.095), PWV (SMD -0.09 m/s (95% CI -0.24, 0.07), p = 0.275) and AIx (SMD 0.05% (95% CI -0.1, 0.19), p = 0.52) showed no improvement with vitamin D supplementation. Sub-analysis and meta-regression revealed a tendency for AIx and FMD% to increase as weekly vitamin doses increased; no other significant relationships were identified.

CONCLUSIONS

Vitamin D supplementation showed no improvement in endothelial function. More evidence is required before recommendations for management of endothelial dysfunction can be made.

The confirmation of treatment effects in Japanese acupuncture

BACKGROUND

Japanese acupuncture is gaining international recognition. However, previous research has failed to comprehensively describe the characteristics of Japanese acupuncture by not investigating it within the Japanese clinical environment. This qualitative ethnographic study aimed to identify unique and routine elements of Japanese acupuncture, describe these in detail and examine how they related to treatment principles.

METHODS

Between August 2012 and December 2016, ethnographic fieldwork was conducted in Japan. Participants were recruited by chain referral and emergent sampling. Data were collected through participant observation and interviews as well as by analyzing documents. A total of 38 participants were recruited. A total of 22 agreed to clinical observation; 221 treatments were observed with 172 patients. Seventeen participants consented to participate in formal interviews and 28 to informal interviews. Thematic analysis was used to evaluate data.

RESULTS

That practitioners tended to confirm perceived effects of interventions during treatment, was a major theme interpreted from the data. Confirmation was performed continually throughout treatment and at three different levels of timing and anatomical areas (micro, meso and macro). Many markers signified treatment effects which were in general, perceived by observing and/or palpating body tissue. Belief in the instantaneous effects of treatment and the value of effect through technique exemplify the philosophical foundations of confirmation. Continually monitoring treatment results at a range of time and body location increments is an important element of Japanese acupuncture.

CONCLUSION

This effect confirmation practice model promotes a system of constant feedback gained by repeated intervention and confirmation. This may be a unique feature of Japanese acupuncture.

Contact Tools in Japanese Acupuncture: An Ethnography of Acupuncture Practitioners in Japan

This study aimed to identify procedural elements of Japanese acupuncture, describe these elements in detail, and explain them in terms of the key thematic category of treatment principles. Between August 2012 and December 2016, ethnographic fieldwork was conducted in Japan. In total, 38 participants were recruited by chain referral and emergent sampling. Data was collected through participant observation, interviews, and by analyzing documents. A total of 22 participants agreed to clinical observation; 221 treatments were observed with 172 patients. Seventeen consented to formal interviews and 28 to informal interviews. Thematic analysis was used to critically evaluate data. One especially interesting theme was interpreted from the data: a variety of contact tools were applied in treatment and these were manipulated by adjusting elements of form, speed, repetition, and pressure. Tapping, holding, pressing/pushing, and stroking were the most important ways contact tools were used on patients. Contact tools are noninvasive, painless, can be applied in almost any environment, and may be easily accepted by patients worldwide. Contact tool theory and practice may be successfully integrated into acupuncture curricula outside of Japan, used to inform clinical trials, and contribute to an expanded repertoire of methods for practitioners to benefit individual patients in international contexts.

Beliefs and values in Japanese acupuncture: an ethnography of Japanese trained acupuncture practitioners in Japan

BACKGROUND

Japanese acupuncture is gaining international recognition. However, previous research has failed to comprehensively describe the characteristics of Japanese acupuncture by not investigating it within the Japanese clinical environment. This study aimed to identify unique and routine elements of Japanese acupuncture, describe these elements in detail, and examine how the current beliefs and attitudes of Japanese acupuncture practitioners related to philosophical concepts in their practice.

METHODS

Between August 2012 and December 2016, ethnographic fieldwork was conducted in Japan. Japanese trained acupuncture practitioners were recruited by chain referral and emergent sampling. Data were collected through participant observation, interviews, and by analyzing documents. Thematic analysis was used to critically evaluate the data.

RESULTS

Thirty-eight participants were recruited. Of these participants, 22 agreed to clinical observation; 221 treatments were observed with 172 patients. Additionally, 17 participants consented to participate in formal semistructured interviews and 28 to informal unstructured interviews (fieldwork discussion). Besides "knowledge," "beliefs and values" was a major theme interpreted from the data. Subthemes-including Zen Buddhism, effect through technique, instant effects of treatment, anatomical areas of significance, resolution of abnormalities, minimal stimulation, and patient comfort and customer service-were identified.

CONCLUSION

Beliefs and values are an underrepresented, yet extremely important aspect of philosophical concepts influencing acupuncture practice in Japan. Uniquely Japanese beliefs and values that do not rely on a commitment to any spiritual or religious affiliations or proprietary knowledge of traditional or biomedicine may be successfully exported from Japan to advance acupuncture education, research and practice in international contexts.

The efficacy of isometric resistance training utilizing handgrip exercise for blood pressure management: A randomized trial

INTRODUCTION

Hypertension is a major risk factor contributing to cardiovascular disease, which is the number one cause of deaths worldwide. Although antihypertensive medications are effective at controlling blood pressure, current first-line treatment for hypertension is nonpharmacological lifestyle modifications. Recent studies indicate that isometric resistance training (IRT) may also be effective for assisting with blood pressure management. The aim of this study was to determine the efficacy of IRT for blood pressure management and the suitability of a low-intensity working control group.

METHODS

Forty hypertensive individuals, aged between 36 and 65 years, conducted IRT for 8 weeks. Participants were randomized into 2 groups, working at an intensity of either 5% or 30% of their maximum voluntary contraction. Participants performed 4 × 2 minute isometric handgrip exercises with their nondominant hand, each separated by a 3-minute rest period, 3 days a week.

RESULTS

Blood pressure measurements were conducted at baseline and at the end of the protocol using a Finometer. Eight weeks of isometric resistance training resulted in a 7-mmHg reduction of resting systolic blood pressure (SBP) (136 ± 12 to 129 ± 15; P = 0.04) in the 30% group. Reductions of 4 mmHg were also seen in mean arterial pressure (MAP) (100 ± 8 to 96 ± 11; P = 0.04) in the 30% group. There were no statistically significant reductions in diastolic blood pressure for the 30% group, or any of the data for the 5% group.

CONCLUSION

Isometric resistance training conducted using handgrip exercise at 30% of maximum voluntary contraction significantly reduced SBP and MAP. A lack of reduction in blood pressure in the 5% group indicates that a low-intensity group may be suitable as a working control for future studies.

Effect of exercise training on liver function in adults who are overweight or exhibit fatty liver disease: a systematic review and meta-analysis

OBJECTIVE

Exercise training has been shown to have beneficial effects on liver function in adults overweight or with fatty liver disease. To establish which exercise programme characteristics were likely to elicit optimal improvements.

DESIGN

Systematic review and meta-analysis of randomised, controlled trials.

DATA SOURCES

PubMed, CINAHL and Cochrane controlled trials registry searched (1966 to 2 October 2015).

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Exercise intervention, with or without dietary intervention, versus usual care in adults undertaking, exercise training, who were overweight, obese or exhibited fatty liver disease (non-alcoholic fatty liver disease or non-alcoholic steatohepatitis).

RESULTS

We included 21 randomised controlled trials, totalling 1530 participants. Exercise intervention studies with total exercise programme workload >10 000 kcal produced significant improvements in intrahepatic fat, -3.46% (95% CI -5.20% to -1.73%), p<0.0001, I²=73%; effect size (standardised mean difference, SMD) -1.77 (-3.11 to -0.42), p=0.01, I²=77%. When data from only exercise studies were pooled, there was a reduction in fasting free fatty acids (FFAs) -74.15 µmol/L (95% CI -118.47 to -29.84), p=0.001, I²=67% with a large effect size (SMD) -0.94 (-1.36 to -0.52), p<0.0001, I²=0%. When data from only exercise studies were pooled, there was a significant reduction in insulin MD -1.88 UL (95% CI -3.43 to -0.34), p=0.02, I²=31%. The liver enzymes, alanine aminotransferase, aspartate aminotransferase and γ-glutamyl transpeptidase, were not significantly altered with exercise.

CONCLUSIONS

Exercise training reduces intrahepatic fat and FFAs while increasing cardiorespiratory fitness. An aggregate exercise programme energy expenditure (>10 000 kcal) may be required to promote reductions in intrahepatic fat.

Isometric exercise training for blood pressure management: a systematic review and meta-analysis to optimize benefit

The objective of our study was to examine the effects of isometric resistance training (IRT) on resting blood pressure in adults. We conducted a systematic review and meta-analysis of randomized-controlled trials lasting ⩾2 weeks, investigating the effects of isometric exercise on blood pressure in healthy adults (aged ⩾18 years), published in a peer-reviewed journal between 1 January 1966 to 31 January 2015. We included 11 randomized trials, totaling 302 participants. The following reductions were observed after isometric exercise training; systolic blood pressure (SBP) mean difference (MD) -5.20 mm Hg (95% confidence interval (CI) -6.08 to -4.33, P<0.00001); diastolic blood pressure (DBP) MD -3.91 mm Hg (95% CI -5.68 to -2.14, P<0.0001); and mean arterial blood pressure (MAP) MD -3.33 mm Hg (95% CI -4.01 to -2.66, P<0.00001). Sub-analyses showed males tended to reduce MAP MD -4.13 mm Hg (95% CI -5.08 to -3.18) more than females. Subjects aged ⩾45 years demonstrated larger reductions in MAP MD -5.51 mm Hg (95% CI -6.95 to -4.06) than those <45 years. Subjects undertaking ⩾8 weeks of IRT demonstrated a larger reduction in SBP MD -7.26 mm Hg (95% CI -8.47 to -6.04) and MAP MD -4.22 mm Hg (95% CI -5.08 to -3.37) than those undertaking<8 weeks. Hypertensive participants in IRT demonstrated a larger reduction in MAP MD -5.91 mm Hg (95% CI -7.94 to -3.87) than normotensive participants MD -3.01 mm Hg (95% CI -3.73 to -2.29). Our study indicated that IRT lowers SBP, DBP and MAP. The magnitude of effect may be larger in hypertensive males aged ⩾45 years, using unilateral arm IRT for >8 weeks.

Clinical outcomes and cardiovascular responses to exercise training in heart failure patients with preserved ejection fraction: a systematic review and meta-analysis

Exercise training induces physical adaptations for heart failure patients with systolic dysfunction, but less is known about those patients with preserved ejection fraction. To establish whether exercise training produces changes in peak V̇o2 and related measures, quality of life, general health, and diastolic function in heart failure patients with preserved ejection fraction. We conducted a MEDLINE search (1985 to October 10, 2014), for exercise-based rehabilitation trials in heart failure, using search terms "exercise training, heart failure with preserved ejection fraction, heart failure with normal ejection fraction, peak V̇o₂, and diastolic heart dysfunction". Seven intervention studies were included providing a total of 144 exercising subjects and 114 control subjects, a total of 258 participants. Peak V̇o₂ increased by a mean difference (MD) 2.13 ml·kg(-1)·min(-1) [95% confidence interval (CI) 1.54 to 2.71, P < 0.00001] in exercise training vs. sedentary control, equating to a 17% improvement from baseline. The corresponding data are provided for the following exercise test variables: V̇e/V̇co₂ slope, MD 0.85 ml·kg(-1)·min(-1) (95% CI 0.05 to 1.65, P = 0.04); maximum heart rate, MD 5.60 beats per minute (95% CI 3.95 to 7.25, P < 0.00001); Six-Minute Walk Test, MD 32.1 m (95% CI 17.2 to 47.1, P < 0.0001); and indices of diastolic function: E/A ratio, MD 0.07 (95% CI 0.02 to 0.12, P = 0.005); E/E' ratio MD -2.31 (95% CI -3.44 to -1.19, P < 0.0001); deceleration time (DT), MD -13.2 ms (95% CI -19.8 to -6.5, P = 0.0001); and quality of life: Minnesota Living with Heart Failure Questionnaire, MD -6.50 (95% CI -9.47 to -3.53, P < 0.0001); and short form-36 health survey (physical dimension), MD 15.6 (95% CI 7.4 to 23.8, P = 0.0002). In 3,744 h patient-hours of training, not one death was directly attributable to exercise. Exercise training appears to effect several health-related improvements in people with heart failure and preserved ejection fraction.

Exercise training for health-related quality of life in peripheral artery disease: A systematic review and meta-analysis

We sought to quantify whether health-related quality of life (HRQoL) is improved through exercise training in people with peripheral artery disease (PAD) and to clarify which prescriptions were optimal for improving HRQoL when compared to usual care. We conducted a systematic search (PubMed, CINAHL, Cochrane Central Register of Controlled Trials; 1966 – 31 August 2014). We only included randomized controlled trials (RCTs) of exercise training versus usual medical care in persons with PAD that included the Walking Impairment Questionnaire (WIQ) and Short-Form Health Survey component summary scores as outcomes. Of 15 RCTs, 1257 participants were studied: 543 participated in supervised exercise, with only 61 undertaking resistance training and 316 unsupervised exercise. When compared to controls, participants who completed any form of exercise training significantly improved their WIQ speed [mean difference (MD) 9.60 (95% CI 6.98 to 12.23, p<0.00001)]; WIQ distance [MD 7.41 (95% CI 4.49 to 10.33, p<0.00001)] and WIQ stair-climbing [MD 5.07 (95% CI 3.16 to 6.99, p<0.00001)]. Walking also significantly improved the Short-Form Physical Component Summary (SF-PCS) score when compared to controls [MD 1.24 (95% CI 0.48 to 2.01, p=0.001)], but not the Mental Component Summary (SF-MCS) score [MD –0.55 (95% CI –1.27 to 0.18, p=0.14)]. Exercise training improves the SF-PCS dimension, as well as perceived walking distance, speed and stair-climbing as measured by the WIQ, but not the SF-MCS score. Future studies should aim to blind assessors of such subjective measures, and study alternative modes and prescriptions of exercise alternative to walking.

Early referral to specialist nephrology services for preventing the progression to end-stage kidney disease

BACKGROUND

Early referral of patients with chronic kidney disease (CKD) is believed to help with interventions to address risk factors to slow down the rate of progression of kidney failure to end-stage kidney disease (ESKD) and the need for dialysis, hospitalisation and mortality.

OBJECTIVES

We sought to evaluate the benefits (reduced hospitalisation and mortality; increased quality of life) and harms (increased hospitalisations and mortality, decreased quality of life) of early versus late referral to specialist nephrology services in CKD patients who are progressing to ESKD and RRT. In this review, referral is defined as the time period between first nephrology evaluation and initiation of dialysis; early referral is more than one to six months, whereas late referral is less than one to six months prior to starting dialysis. All-cause mortality and hospitalisation and quality of life were measured by the visual analogue scale and SF-36. SF-36 and KDQoL are validated measurement instruments for kidney diseases.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2012; Issue 1) which contains the Cochrane Renal Group's Specialised Register; MEDLINE (1966 to February 2012), EMBASE (1980 to February 2012). Search terms were approved by the Trial Search Co-ordinator.

SELECTION CRITERIA

Randomised controlled trials (RCTs), quasi-RCTs, prospective and retrospective longitudinal cohort studies were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Events relating to adverse effects were collected from the studies.

MAIN RESULTS

No RCTs or quasi-RCTs were identified. There were 40 longitudinal cohort studies providing data on 63,887 participants; 43,209 (68%) who were referred early and 20,678 (32%) referred late.Comparative mortality was higher in patients referred to specialist services late versus those referred early. Risk ratios (RR) for mortality reductions in patients referred early were evident at three months (RR 0.61, 95% CI 0.55 to 0.67; I² = 84%) and remained at five years (RR 0.66, 95% CI 0.60 to 0.71; I² = 87%). Initial hospitalisation was 9.12 days shorter with early referral (95% CI -10.92 to -7.32 days; I² = 82%) compared to late referral. Pooled analysis showed patients referred early were more likely than late referrals to initiate RRT with peritoneal dialysis (RR 1.74, 95% CI 1.64 to 1.84; I² = 92%).Patients referred early were less likely to receive temporary vascular access (RR 0.47, 95% CL 0.45 to 0.50; I² = 97%) than those referred late. Patients referred early were more likely to receive permanent vascular access (RR 3.22, 95% CI 2.92 to 3.55; I² = 97%). Systolic blood pressure (BP) was significantly lower in early versus late referrals (MD -3.09 mm Hg, 95% CI -5.23 to -0.95; I² = 85%); diastolic BP was significantly lower in early versus late referrals (MD -1.64 mm Hg, 95% CI -2.77 to -0.51; I² = 82%). EPO use was significantly higher in those referred early (RR 2.92, 95% CI 2.42 to 3.52; I² = 0%). eGFR was higher in early referrals (MD 0.42 mL/min/1.73 m², 95% CI 0.28 to 0.56; I² = 95%). Diabetes prevalence was similar in patients referred early and late (RR 1.05, 95% CI 0.96 to 1.15; I² = 87%) as was ischaemic heart disease (RR 1.05, 95% CI 0.97 to 1.13; I² = 74%), peripheral vascular disease (RR 0.99, 95% CI 0.84 to 1.17; I² = 90%), and congestive heart failure (RR 1.00, 95% CI 0.86 to 1.15; I² = 92%). Inability to walk was less prevalent in early referrals (RR 0.66, 95% CI 0.51 to 0.86). Prevalence of chronic obstructive pulmonary disease was similar in those referred early and late (RR 0.89, 95% CI 0.70 to 1.14; I² = 94%) as was cerebrovascular disease (RR 0.90, 95% CI 0.74 to 1.11; I² = 83%).The quality of the included studies was assessed as being low to moderate based on the Newcastle-Ottawa Scale. Slight differences in the definition of early versus late referral infer some risk of bias. Generally, heterogeneity in most of the analyses was high.

AUTHORS' CONCLUSIONS

Our analysis showed reduced mortality and mortality and hospitalisation, better uptake of peritoneal dialysis and earlier placement of arteriovenous fistulae for patients with chronic kidney disease who were referred early to a nephrologist. Differences in mortality and hospitalisation data between the two groups were not explained by differences in prevalence of comorbid disease or serum phosphate. However, early referral was associated with better preparation and placement of dialysis access.

Clinical outcomes and cardiovascular responses to different exercise training intensities in patients with heart failure: a systematic review and meta-analysis

OBJECTIVES

The aim of this study was to establish whether aerobic exercise training intensity produces different effect sizes for fitness, adherence, event rates, mortality rates, and hospitalization rates in patients with heart failure.

BACKGROUND

Intuitively, greater exercise intensity is considered to result in higher risk for serious events, but intensity may be the primary stimulus for physical adaptation.

METHODS

A MEDLINE search (1985 to 2012) was conducted for exercise-based rehabilitation trials in heart failure, using the search terms "exercise training," "left ventricular dysfunction," "peak Vo2," "cardio-myopathy," and "systolic heart dysfunction." Seventy-four studies were included, producing 76 intervention groups; 9 (11.8%) were high-intensity, 38 (50%) vigorous-intensity, 24 (31.6%) moderate-intensity, and 5 (6.6%) low-intensity groups, providing a total of 3,265 exercising subjects and 2,612 control subjects.

RESULTS

Peak oxygen consumption increased by a mean difference of 3.33 ml·kg(-1)·min(-1) (95% confidence interval [CI]: 0.53 to 6.13 ml·kg(-1)·min(-1); p = 0.02) with high-intensity training in exercise groups compared with control groups, equating to a 23% improvement from baseline. For vigorous intensity, the mean difference was 2.27 ml·kg(-1)·min(-1) (95% CI: 1.70 to 2.84 ml·kg(-1)·min(-1); p < 0.00001), with an 8% weighted mean; for moderate intensity, the mean difference was 2.17 ml·kg(-1)·min(-1) (95% CI: 1.34 to 2.99 ml·kg(-1)·min(-1); p < 0.00001), with a weighted mean of 13%; and for low intensity, the mean difference was 1.04 ml·kg(-1)·min(-1) (95% CI: -2.50 to 4.57 ml·kg(-1)·min(-1); p = 0.57), with a weighted mean of 7%. In 123,479 patient-hours of training, not a single death was directly attributable to exercise.

CONCLUSIONS

As exercise training intensity rises, so may the magnitude of improvement in cardiorespiratory fitness, accompanied by lower study withdrawal in exercising patients. Total exercise time may be a confounder.

Isometric exercise training for blood pressure management: a systematic review and meta-analysis

OBJECTIVE

To conduct a systematic review and meta-analysis quantifying the effects of isometric resistance training on the change in systolic blood pressure(SBP), diastolic blood pressure (DBP), and mean arterial pressure in subclinical populations and to examine whether the magnitude of change in SBP and DBP was different with respect to blood pressure classification.

PATIENTS AND METHODS

We conducted a systematic review and meta-analysis of randomized controlled trials lasting 4 or more weeks that investigated the effects of isometric exercise on blood pressure in healthy adults (aged ≥18 years) and were published in a peer-reviewed journal. PubMed, CINAHL, and the Cochrane Central Register of Controlled Trials were searched for trials reported between January 1, 1966, and July 31, 2013. We included 9 randomized trials, 6 of which studied normotensive participants and 3 that studied hypertensive patients, that included a total of 223 participants (127 who underwent exercise training and 96 controls).

RESULTS

The following reductions were observed after isometric exercise training: SBP-mean difference (MD), -6.77 mm Hg (95% CI, -7.93 to -5.62 mm Hg; P<.001); DBP-MD, -3.96 mm Hg (95% CI, -4.80 to -3.12 mm Hg; P<.001); and mean arterial pressure-MD, -3.94 mm Hg (95% CI, -4.73 to -3.16 mm Hg; P<.001). A slight reduction in resting heart rate was also observed (MD, -0.79 beats/min; 95% CI, -1.23 to -0.36 beats/min; P=.003).

CONCLUSION

Isometric resistance training lowers SBP, DBP, and mean arterial pressure. The magnitude of effect is larger than that previously reported in dynamic aerobic or resistance training. Our data suggest that this form of training has the potential to produce significant and clinically meaningful blood pressure reductions and could serve as an adjunctive exercise modality.

Effect of lifestyle intervention on the reproductive endocrine profile in women with polycystic ovarian syndrome: a systematic review and meta-analysis

Polycystic ovarian syndrome (PCOS) affects 18-22% of women at reproductive age. We conducted a systematic review and meta-analysis evaluating the expected benefits of lifestyle (exercise plus diet) interventions on the reproductive endocrine profile in women with PCOS. Potential studies were identified by systematically searching PubMed, CINAHL and the Cochrane Controlled Trials Registry (1966-April 30, 2013) systematically using key concepts of PCOS. Significant improvements were seen in women receiving lifestyle intervention vs usual care in follicle-stimulating hormone (FSH) levels, mean difference (MD) 0.39 IU/l (95% CI 0.09 to 0.70, P=0.01), sex hormone-binding globulin (SHBG) levels, MD 2.37 nmol/l (95% CI 1.27 to 3.47, P<0.0001), total testosterone levels, MD -0.13 nmol/l (95% CI -0.22 to -0.03, P=0.008), androstenedione levels, MD -0.09 ng/dl (95% CI -0.15 to -0.03, P=0.005), free androgen index (FAI) levels, MD -1.64 (95% CI -2.94 to -0.35, P=0.01) and Ferriman-Gallwey (FG) score, MD -1.01 (95% CI -1.54 to -0.48, P=0.0002). Significant improvements were also observed in women who received exercise-alone intervention vs usual care in FSH levels, MD 0.42 IU/l (95% CI 0.11 to 0.73, P=0.009), SHBG levels, MD 3.42 nmol/l (95% CI 0.11 to 6.73, P=0.04), total testosterone levels, MD -0.16 nmol/l (95% CI -0.29 to -0.04, P=0.01), androstenedione levels, MD -0.09 ng/dl (95% CI -0.16 to -0.03, P=0.004) and FG score, MD -1.13 (95% CI -1.88 to -0.38, P=0.003). Our analyses suggest that lifestyle (diet and exercise) intervention improves levels of FSH, SHBG, total testosterone, androstenedione and FAI, and FG score in women with PCOS.

Exercise training program characteristics and magnitude of change in functional capacity of heart failure patients

BACKGROUND

Intuitively higher exercise program volume may be the primary stimulus for physical adaptation. We sought to establish if aerobic exercise training program characteristics produced different effect sizes for change in cardiorespiratory fitness in heart failure patients.

METHODS

We conducted a MEDLINE search (1966 to 2012), for exercise based rehabilitation trials in heart failure, using the search terms 'exercise training, left ventricular dysfunction, peak VO2, cardio-myopathy and systolic heart dysfunction'. Forty seven studies were included, producing 54 intervention groups; 3 (6%) were high-, 29 (54%) vigorous-, 20 (37%) moderate- and 2 (3%) low- intensity groups, providing a total of 2285 exercising subjects and 2098 control subjects, totaling 4383 participants.

RESULTS

Peak VO2 increased by a mean difference of 3.3 ml kg(-1)min(-1) [95% CI 0.53 to 6.13, p=0.02] with high intensity training in exercise groups versus control, equating to a 23% improvement from baseline. The corresponding data for vigorous, moderate and low intensity were 8%, 13%; and 7% respectively. Weekly exercise energy expenditure >460 kcal was associated with a mean difference in peak VO2 of 2.6 ml kg(-1)min(-1) [95% CI 1.88 to 3.28, p<0.00001].

CONCLUSIONS

Our data suggest that high-intensity exercise, achieving at least 460 kcal weekly energy expenditure may elicit the greatest changes in cardiorespiratory fitness.

Clinical outcomes and cardiovascular responses to different exercise training intensities in patients with heart failure: a systematic review and meta-analysis

OBJECTIVES

The aim of this study was to establish whether aerobic exercise training intensity produces different effect sizes for fitness, adherence, event rates, mortality rates, and hospitalization rates in patients with heart failure.

BACKGROUND

Intuitively, greater exercise intensity is considered to result in higher risk for serious events, but intensity may be the primary stimulus for physical adaptation.

METHODS

A MEDLINE search (1985 to 2012) was conducted for exercise-based rehabilitation trials in heart failure, using the search terms "exercise training," "left ventricular dysfunction," "peak Vo2," "cardio-myopathy," and "systolic heart dysfunction." Seventy-four studies were included, producing 76 intervention groups; 9 (11.8%) were high-intensity, 38 (50%) vigorous-intensity, 24 (31.6%) moderate-intensity, and 5 (6.6%) low-intensity groups, providing a total of 3,265 exercising subjects and 2,612 control subjects.

RESULTS

Peak oxygen consumption increased by a mean difference of 3.33 ml·kg(-1)·min(-1) (95% confidence interval [CI]: 0.53 to 6.13 ml·kg(-1)·min(-1); p = 0.02) with high-intensity training in exercise groups compared with control groups, equating to a 23% improvement from baseline. For vigorous intensity, the mean difference was 2.27 ml·kg(-1)·min(-1) (95% CI: 1.70 to 2.84 ml·kg(-1)·min(-1); p < 0.00001), with an 8% weighted mean; for moderate intensity, the mean difference was 2.17 ml·kg(-1)·min(-1) (95% CI: 1.34 to 2.99 ml·kg(-1)·min(-1); p < 0.00001), with a weighted mean of 13%; and for low intensity, the mean difference was 1.04 ml·kg(-1)·min(-1) (95% CI: -2.50 to 4.57 ml·kg(-1)·min(-1); p = 0.57), with a weighted mean of 7%. In 123,479 patient-hours of training, not a single death was directly attributable to exercise.

CONCLUSIONS

As exercise training intensity rises, so may the magnitude of improvement in cardiorespiratory fitness, accompanied by lower study withdrawal in exercising patients. Total exercise time may be a confounder.

Efficacy of inspiratory muscle training in chronic heart failure patients: a systematic review and meta-analysis

INTRODUCTION

Inspiratory muscle training (IMT) offers an alternative to exercise training (ExT) in the most severely deconditioned heart failure patients who are unable to exercise. We conducted a meta-analysis to determine magnitude of change in peak VO2, six minute walk distance (6MWD), Quality of Life measured by the Minnesota Living with Heart Failure Questionnaire (MLWHFQ), maximal inspiratory pressure (PI max) and ventilatory equivalent for carbon dioxide (VE/VCO2 slope) with IMT.

METHODS

A systematic search was conducted of randomized, controlled trials of IMT therapy in CHF patients using Medline (Ovid) (1950-February 2012), Embase.com (1974-February 2012), Cochrane Central Register of Controlled Trials and CINAHL (1981-February 2012). The search strategy included a mix of MeSH and free text terms for the key concepts heart failure, inspiratory or respiratory muscle training, exercise training

RESULTS

The eleven included studies contained data on 287 participants: 148 IMT participants and 139 sham or sedentary control. Compared to control groups, CHF patients undergoing IMT showed a significant improvement in peak VO2 (+1.83 ml kg(-1) min(-1), 95% C.I. 1.33 to 2.32 ml kg(-1) min(-1), p<0.00001); 6 MWD (+34.35 m, 95% C.I. 22.45 to 46.24 m, p<0.00001); MLWHFQ (-12.25, 95% C.I. -17.08 to -7.43, p<0.00001); PImax (+20.01, 95% C.I. 13.96 to 26.06, p<0.00001); and VE/VCO2 slope (-2.28, 95% C.I. -3.25 to -1.30, p<0.00001).

CONCLUSIONS

IMT improves cardio-respiratory fitness and quality of life to a similar magnitude to conventional exercise training and may provide an initial alternative to the more severely de-conditioned CHF patients who may then transition to conventional ExT.

Functional electrical stimulation for chronic heart failure: a meta-analysis

INTRODUCTION

We conducted a meta-analysis of randomized, controlled trials of combined electrical stimulation versus conventional exercise training or placebo control in heart failure patients.

METHODS

A systematic search was conducted of Medline (Ovid) (1950-September 2011), Embase.com (1974-September 2011), Cochrane Central Register of Controlled Trials and CINAHL (1981-September 2011). The search strategy included a mix of MeSH and free text terms for the key concepts heart failure, exercise training and functional electrical stimulation (FES).

RESULTS

FES produced inferior improvements in peak VO2 when compared to cycle training: mean difference (MD) -0.32 ml.kg(-1).min(-1) (95% C.I. -0.63 to -0.02 ml.kg(-1).min(-1), p=0.04), however FES elicited superior improvements in peak VO2: MD 2.30 ml.kg(-1).min(-1) (95% C.I. 1.98 to 2.62 ml.kg(-1).min(-1), p<0.00001); and six minute walk distance to sedentary care or sham FES; MD 46.9 m (95% C.I. 22.5 to 71.3m, p=0.0002). There was no difference in change in quality of life between cycling and FES, but FES elicited significantly larger improvements in Minnesota Living with Heart Failure score than placebo or sham treatment; MD 1.15 (95% C.I. 0.69 to 1.61, p<0.00001). Moreover, the total FES intervention hours were strongly correlated with change in peak VO2, (r=0.80, p=0.02).

CONCLUSIONS

Passive or active exercise is beneficial for patients with moderate to severe heart failure, but active cycling, or other aerobic/resistance activity is preferred in patients with heart failure who are able to exercise, and FES is the preferred modality in those unable to actively exercise. The benefits of FES may however, be smaller than those observed in conventional exercise training. Aggregate hours of electrical stimulation therapy were associated with larger improvements in cardio-respiratory fitness.

Effects of acute insulin deficiency on catecholamine and indoleamine content and catecholamine turnover in microdissected hypothalamic nuclei in streptozotocin-diabetic rats

The effects of streptozotocin-induced diabetes on catecholamine and indoleamine concentrations and catecholamine turnover rates in individual microdissected hypothalamic nuclei known, or believed, to be involved in the control of neuroendocrine function, were examined in control, insulin-treated diabetic and acutely insulin-withdrawn diabetic female rats. Streptozotocin-induced diabetes and acute insulin deficiency were demonstrated to result in increased concentrations of epinephrine in the suprachiasmatic nucleus, decreased turnover of epinephrine in the arcuate nucleus and decreased turnover of dopamine in the ventromedial nucleus was found to be increased in the insulin-treated diabetic animals. These data indicate that experimental diabetes and acute insulin deficiency result in the rapid onset of detectable alterations in epinephrine and dopamine activity in specific hypothalamic nuclei. These diabetes-induced changes may cause, or contribute to, the development of secondary neuroendocrine abnormalities known to occur in the diabetic condition.

Modulation of growth hormone-releasing factor stimulated growth hormone secretion by plasma glucose and free fatty acid concentrations in sheep

Effects of plasma glucose and free fatty acid (FFA) concentrations on bovine growth hormone-releasing factor (bGRF)-induced release of growth hormone (GH) were examined in ovariohysterectomized sheep. In experiment 1, the effects of an infusion of insulin (0.025 U/kg BW.h-1), glucose (40 mg/kg BW.h-1), insulin plus glucose or saline on the subsequent effects of bGRF on plasma GH concentrations were determined. Insulin-induced hypoglycemia inhibited GRF effects on plasma GH concentrations while glucose infusion enhanced bGRF actions. Infusing a higher glucose dose (120 mg/kg BW.h-1) had no effect on GRF actions. Subsequently, infusion of FFA (0.25 g/kg/.h-1), nicotinic acid (50 mg/kg BW) or saline for 1 h prior to bGRF injection demonstrated that FFA inhibited GRF actions but FFA depletion by nicotinic acid infusion had no effect on GRF actions. Nicotinic acid (40 mg/kg BW.h-1) infused for 2 h prior to bGRF injection significantly enhanced bGRF-stimulated GH secretion. Finally, to determine whether central nervous system glucopenia produced similar effects to insulin-induced hypoglycemia, 2-deoxyglucose (500 mg) was injected into the lateral ventricle followed in 1 by the i.v. injection of bGRF. The central glucopenia produced by 2-DG inhibited GRF-stimulated GH release. These data demonstrate that decreased peripheral or central nervous system glucose availability and exogenous administration of FFA antagonized GRF-induced release of GH. And, pharmacologic depletion of circulating FFA for at least 2 h facilitated GRF-induced release of GH.

Effects of parachlorophenylalanine, quipazine and cyproheptadine on growth hormone and adrenocorticotropin secretion in steers

Adrenergic and perhaps dopaminergic neurons provide inhibitory regulation of growth hormone (GH) secretion in ruminants. This suggests that either serotonergic or other neurons regulate the stimulatory release of GH. The nature of neurotransmitter control of adrenocorticotropin (ACTH) secretion in ruminants has not been determined. Parachlorophenylalanine (PCPA; serotonin synthesis inhibitor), quipazine (serotonin receptor agonist) and cyproheptadine (serotonin receptor antagonist) were utilized in Holstein steers to determine whether serotonin receptors mediate stimulatory actions on GH and ACTH secretion. PCPA (100 mg/kg BW) administered each day at 1900 hr for three successive days did not alter mean GH concentrations, amplitude of GH peaks, nor the number of GH peaks. Likewise, PCPA altered none of these parameters for ACTH. Quipazine injected iv at .1 or .5 mg/kg BW increased plasma GH (P less than .05) and ACTH (P less than .001) concentrations. There was a dose effect of quipazine on both GH (P less than .05) and ACTH (P less than .0001) secretion. Pretreatment of steers with cyproheptadine (.06 and .6 mg/kg BW) reduced the stimulation of GH by quipazine (P less than .0001) and decreased basal GH concentrations (P less than .0004). Cyproheptadine at .06 mg/kg BW did not alter quipazine effects on ACTH, however, the higher dose decreased the peak ACTH response (P less than .02) to quipazine. Studies with quipazine and cyproheptadine indicated that serotonergic mechanisms are likely involved in the regulation of GH and ACTH secretion in steers.

Effect of fasting and dexamethasone on binding characteristics of canine erythrocyte insulin receptors

Insulin binding characteristics of canine erythrocyte insulin receptors were studied before and after a 72-hour fast, and one and three days following glucocorticoid (dexamethasone) administration. The 72-hour fast tended to increase maximum insulin binding, but no significant differences were found. The administration of dexamethasone resulted in an increased maximum binding of insulin to its receptors which, at day 1, was due to an increase in receptor concentration, and at day 3, to an increased insulin binding affinity of the receptor. These data suggest that the erythrocyte insulin receptor may be useful in clinical and experimental studies in the dog.

Binding characteristics of swine erythrocyte insulin receptors

Crossbred gilts (controls; n = 7) had 8.8 +/- 1.1% (mean +/- SEM) maximum binding of [125I]insulin to insulin receptors on erythrocytes. The number of insulin-binding sites per cell was 137 +/- 19, with a binding affinity ranging from 7.4 X 10(7)M-1 to 11.2 X 10(7)M-1 and mean of 8.8 X 10(7)M-1. Pregnant sows (n = 5) had a significant increase (P less than 0.01) in maximum binding due to an increase in number of receptor sites per cell. Lactating sows fed a high-fiber diet (n = 3) and a low-fiber diet (n = 4) did not develop a significant difference in maximum binding of insulin. Sows fed the low-fiber diet had a significantly higher number of binding sites and a significantly lower binding affinity than did sows fed a high-fiber diet. Receptor-binding affinity was lower in the low-fiber diet group than in cycling gilts, whereas data from sows fed the high-fiber diet did not differ from data for cycling gilts. Data from this study indicated that insulin receptors of swine erythrocytes have binding characteristics similar to those in other species. Pregnancy and diet will alter insulin receptor binding in swine.

Crayfish abdominal muscle adenylate cyclase. Studies on the stimulation by a Ca2+-binding protein

A plasma-membrane preparation of crayfish muscle showed an adenylate cyclase activity which is inhibited to about 80% of its original activity by 100 microM-EGTA. Measurements of the enzyme activity in the presence of 100 microM-EGTA and various concentrations of Ca2+ revealed an increase in enzyme activity of about 400%, indicating an adenylate cyclase which is dependent on Ca2+ for activity. Fluphenazine (1 mM), a blocker of the Ca2+-binding protein calmodulin, decreased enzyme activity to zero. The enzyme can be re-activated by the addition of certain concentrations of calmodulin to the assay medium. This suggests that crayfish muscle adenylate cyclase is dependent on Ca2+ and calmodulin for activity.