bluuebunny/crossref_metadata_2025 huggingface dataset:
FOSTERING HOPE IN PEOPLE LIVING WITH AIDS IN AFRICA: THE ROLE OF PRIMARY HEALTH‐CARE WORKERS
Authors: Akinsola Henry Abayomi
Published: March 2003

Today the medical literature is dominated by discussions on issues related to HIV/AIDS. This is not surprising considering the fact that in the history of humankind, the HIV/AIDS scenario has posed one of the greatest challenges. The reality of the physical, socioeconomic and psychological problems associated with the AIDS epidemic has become obvious to the general populace in Africa. Currently, both the AIDS victims and several others in the society continue to entertain the fear of dying from AIDS. The situation has become a source of concern to almost everyone, including primary health‐care (PHC) workers. While several options are being examined to address the AIDS problem in Africa, one area that is often neglected is how to foster hope in people living with AIDS (PLWA) and their caregivers. In an attempt to examine this issue, this paper discusses the concept of hope, the cultural construct of HIV/AIDS in African countries and the role of PHC workers in fostering hope in PLWA. The paper concludes that by assisting the PLWA to develop a good sense of hope, PHC workers will be able to meet an important challenge: how to improve the quality of life for PLWA.
DEVELOPING BETTER CASEMIX EDUCATION FOR RURAL NEW SOUTH WALES
Authors: Bridges John F. P. , Mazevska Deniza , Haas Marion
Published: March 2003

Casemix is now an important mechanism for the planning, evaluation and funding of health services in Australia. In New South Wales (NSW) it was believed that while staff from most hospitals in metropolitan Sydney had become both literate and vocal about casemix, staff from rural areas were less familiar and much less likely to participate in casemix initiatives. In conjunction with the NSW Casemix Clinical Committee (NCCC), NSW Health considered a special program of casemix education for rural NSW. Before an education program was attempted, NSW Health inquired into the specific needs for casemix education in rural NSW. Qualitative and quantitative methods of analysis were used. Results of the quantitative analysis indicate that the understanding of casemix classifications is highest among managers. Of concern were the relatively low proportion of Allied Health staff who had more than a vague understanding of the Sub‐ and Non‐Acute Patient (SNAP) classification; the lack of any knowledge of the Mental Health Costing And Service Classification (MH‐CASC) by nursing staff; and the lack of any knowledge of the emergency department classification: Urgency, Disposition and Age‐related Groups (UDAG), either by clinical or nursing staff. The results of the qualitative analysis show that casemix education for rural areas needs to differ from metropolitan education programs. The analysis also highlights the perception of casemix in rural areas and the special circumstances in rural hospitals that place limits on the ability to use casemix more fully.
PREVENTIVE SOCIAL HEALTH PROGRAMS: ARE THEY AUSTRALIA’S ANSWER TO RISING HEALTH CARE COSTS IN RURAL COMMUNITIES?
Authors: Harvey Peter
Published: March 2003

Although we have good evidence to support the notion that early intervention, prevention and community education programs can mitigate the impact of preventable disease, expanded primary health care is also being promoted by Australian governments as a panacea for reducing growth in demand generally. While preventive programs do reduce acute demand, they may not do so to the extent that resources, currently allocated to the acute sector, can be substituted to provide the additional primary care services necessary to reduce acute demand permanently. These developments have particular relevance for rural and isolated communities where access to acute services is already very limited. What appears to be occurring, in rural South Australia at least, is that traditional acute services are being reduced and replaced with lower level care and social intervention programs. This is well and good, but eventually the acute care being provided in rural health units now will still need to be provided by other units elsewhere and probably at much higher cost to the system and to consumers. Where rural communities have previously managed much of their own acute service demand, they may now be forced to send patients to more distant centres for care but at much greater social and economic cost to individuals and the system.
Food plant selection by the wild Japanese serow (Capricornis crispus) with reference to the traces eaten
Authors: DEGUCHI Yoshitaka , SATO Shusuke , SUGAWARA Kazuo
Published: March 2003

Vegetation and plants eaten by the serow were investigated once a month from spring to autumn in two areas with different vegetative composition of deciduous broad‐leaved trees and forbs. Then we calculated Ivlev's electivity indices (EI) for some plant species and six plant groups: the deciduous broad‐leaved tree, the evergreen broad‐leaved tree, the conifer, the forb, the graminoid and the fern. In Area 1, the frequency of deciduous broad‐leaved trees and forbs was 78.2% and 1.1%, respectively. The proportion of deciduous broad‐leaved trees and forbs eaten was 65.9% and 33.1%, respectively. In Area 2, the frequency of deciduous broad‐leaved trees and forbs was 32.4% and 23.1%, respectively. The proportion of deciduous broad‐leaved trees and forbs eaten was 46.9% and 52.0%, respectively. In Area 1, the deciduous broad‐leaved tree was eaten in proportion to its frequency in the habitat (EI, 0.06–0.05) except in May (−0.32) and June (−0.11). The deciduous broad‐leaved tree was a little selected in Area 2 (0.02–0.46) except in June (−0.41) when serows selected some forb species. In Area 2, forbs were selected throughout the observational period (0.16–0.97), except during July (−0.05) when serows fed mainly on deciduous broad‐leaved trees (0.46).
Comparative study of the innervation of acetylcholinesterase‐positive nerves in the cerebral arterial tree of birds
Authors: KUSABA Haruo , ANDŌ Koichi , NOBORU Masayuki , HAYASHI Kiyonori , FUJIHARA Noboru , IWAMOTO Hisao
Published: March 2003

Acetylcholinesterase (AChE) histochemistry and quantitative analysis were used to investigate and compare the projections and densities of cerebral perivascular AChE nerves in five avian species. In the society finch, AChE nerves arising from the cerebral carotid, internal ethmoidal and vertebral arteries generally have no overlap with each other. This is different from AChE neuronal projections via these three vascular routes reported previously for the pigeon, duck, chicken and quail. AChE nerves supplying the pigeon cerebral arterial tree are the highest in density, predominate in the anterior circulation (AC) rather than in the posterior circulation (PC). Similar differential supply of nerves is also found in the duck, with a marked low density in the PC. In contrast, the chicken PC has a substantial amount of AChE nerves that is larger than the fiber amount contained in the AC. The reduction of nerves is far greater in both the AC and PC of the finch. It is not so prominent as that seen in the quail. The significant difference in the distribution and density of cerebral perivascular AChE nerves presented here may indicate that there are some species‐specific cholinergic controlling mechanisms responsible for the cerebral circulation of birds.
Impact of fermented milk on human health: Cholesterol‐lowering and immunomodulatory properties of fermented milk
Authors: HOSONO Akiyoshi , OTANI Hajime , YASUI Hisako , WATANUKI Masaaki
Published: March 2003

In this review, we focus on the cholesterol‐lowering activity of Lactobacillus gasseri, the immunomodulatory function of casein phosphopeptides (CPPs) and lactic acid bacteria as starters for fermented milk, and the probability and difficulty of creating immunomodulatory fermented milk as a ‘food for specified health use’. Among the starter bacteria used for the preparation of fermented milk, L. gasseri SBT0270 could exert a hypocholesterolemic effect in rats fed a diet high in cholesterol through deconjugation of bile salts. On the other hand, CPPs, having a tripeptide sequence consisting of two phosphoserine residues at N‐ and C‐terminal positions, stimulated lymphocyte proliferation and IgA formation via the increase of interleukin‐5 and interleukin‐6 produced by type 2 helper T cells. The oral ingestion of CPPs enhanced the level of antigen‐specific and total intestinal IgA. Moreover, one strain of bifidobacteria (Bifidobacterium breve YIT4064) and one strain of Lactobacilli (Lactobacillus casei strain Shirota), used as a starter for fermented milk, activated the humoral and cellular immune system, respectively, and prevented various diseases. It is important to elucidate what components modulate and what mechanisms are responsible for the physiological function of fermented milk in order for it to be accepted as a ‘food for specified health use’ claiming immunomodulatory activity.
Effect of enzymes of microbial origin on in vitro digestibilities of dry matter and crude protein in soybean meal
Authors: SALEH Fuad , OHTSUKA Akira , TANAKA Tsuneo , HAYASHI Kunioki
Published: March 2003

The effects of supplementation with cellulase, xylanase, pectinase, hemicellulase, glucanase, phytase and protease of microbial origin on digestibility of crude protein (CP) and dry matter (DM) of soybean meal in vitro were examined in the present study. Changes in viscosity during in vitro digestion were also examined as an index of carbohydrate digestibility. Hemicellulase and all enzyme combinations without protease showed significant improvement of CP digestibility. Cellulase, xylanase, phytase and glucanase tended to improve CP digestibility. Dry matter digestibility was improved significantly by pectinase and all enzyme combinations. Cellulase and phytase tended to improve DM digestibility. Crude protein and DM digestibilities were the highest when all the enzymes except protease were added. Protease, cellulase, pectinase, xylanase, glucanase and hemicellulase significantly reduced viscosity, while phytase had no effect on viscosity. Viscosity was increased unexpectedly when all the enzymes were added. These results strongly suggest that a combination of carbohydrases improves the CP and DM digestibility of soybean meal while protease inhibits the actions of these enzymes. The present study also suggests that viscosity is not always a good index of digestibility. Moreover, excluding the protease from commercial crude enzyme preparations may improve digestibility.
Safety and efficacy of KOGENATE® Bayer in previously untreated patients (PUPs) and minimally treated patients (MTPs)
Authors: Giangrande P. L. F. ,   BAYER STUDY GROUP
Published: March 2003

Summary.  Safety and efficacy of KOGENATE® Bayer (Kogenate® FS), a second‐generation full‐length recombinant factor VIII formulated with sucrose as stabilizer and produced without the addition of human albumin during purification and the final formulation, was assessed in a prospective, international clinical trial including 31 previously untreated patients (PUPs) and minimally treated patients (MTPs) with severe haemophilia A in home therapy and surgery. Factor VIII inhibitor development was monitored and mutation type profiles were analysed. As of 30 June 2000, the patients received a total of 2.729 infusions (mean 88; range 6–274) for bleeding episodes, surgery or prophylactic treatment. No unexpected drug‐related adverse events were observed. Four patients developed an inhibitor after 3–12 exposure days (EDs). One patient successfully underwent immune tolerance treatment; inhibitors in two patients disappeared spontaneously with on‐demand treatment, while the inhibitor titre remains low in one patient. Twenty‐nine patients (93%) with more than 20 EDs can be regarded as at low risk for inhibitor development. In conclusion, KOGENATE® Bayer is efficacious and well‐tolerated for treatment of children with severe haemophilia A. The incidence of inhibitor formation is not different to that observed with other recombinant or plasma‐derived products.
Smoking cessation among daily smokers, aged 45–69 years: a longitudinal study in Malmö, Sweden
Authors: Lindström Martin , Isacsson Sven‐Olof , The Malmö Shoulder–Neck Study Group
Published: March 2003

Objective To investigate differences in snuff consumption, socio‐demographic and psychosocial characteristics between baseline daily smokers who had remained daily smokers, become intermittent smokers or stopped smoking at the 1‐year follow‐up.

Design, setting, participants and measurements A population of 12 507 individuals aged 45–69 years, interviewed at baseline in 1992–94 and at a 1‐year follow‐up, was investigated in this longitudinal study. The three groups of baseline daily smokers were compared to the total population according to socio‐demographic, psychosocial and snuff consumption characteristics. A multivariate logistic regression model was used to assess differences in psychosocial conditions, adjusting for age, sex, country of origin, marital status, education and snuff consumption.

Findings Eighty‐six per cent of all baseline daily smokers remained daily smokers, 6.5% had become intermittent smokers and 7.3% had stopped smoking at the 1‐year follow‐up. The daily smokers who remained daily smokers were more likely to be born in other countries than Sweden, not married, have a lower educational level and poorer psychosocial conditions than the total population, while the socio‐demographic characteristics and psychosocial resources of those daily smokers who had become intermittent smokers or had stopped smoking were much more similar to the general population, with the exception of a higher snuff consumption, especially for intermittent smokers.

Conclusions Daily smokers who remained daily smokers at the 1‐year follow‐up had poorer psychosocial assets, especially social participation, than baseline daily smokers who had become intermittent smokers or had stopped smoking, and the general population. The results suggest that low levels of social participation are a potent barrier against smoking cessation. Snuff consumption may explain a part of the increase in smoking cessation among men as opposed to women in Sweden.
The capillary filtration coefficient for evaluation of capillary fluid permeability in cat calf muscles
Authors: KONGSTAD  , GRÄNDE
Published: March 2003

Measuring the capillary filtration coefficient (CFC) from the transvascular fluid filtration following a fixed increase in transcapillary hydrostatic pressure is a common method to estimate capillary hydraulic permeability (conductivity) in an organ. Constant flow pump perfusion with an artificial perfusate and a maximally dilated vascular bed are often used in CFC studies to avoid influence on CFC of variations in vascular tone, blood flow and perfusion pressure. The present study evaluates if capillary hydraulic conductivity can be estimated by the CFC method, when analyzed on a de‐nervated cat skeletal muscle with quite well‐preserved local vascular control and perfused with autologous blood. CFC was estimated by increasing venous pressure and by decreasing tissue pressure, and both during autoperfusion and pressure controlled pump perfusion. A constant filtration rate was achieved 3–4 min after the transcapillary pressure elevation, giving a CFC around 0.0090 mL min−1 mmHg−1 100 g. The CFC did not change with arterial pressure or with reduced vascular tone using the tissue pressure method, but decreased slightly with increased arterial pressure and reduced vascular tone using the venous pressure method. CFC variations with arterial pressure were larger during pump perfusion in which myogenic reactivity is depressed, indicating that influence of myogenic tone on CFC is small. We conclude that CFC can be used to evaluate capillary hydraulic conductivity, and also when arterial pressure, vascular tone and blood flow are altered within reasonable physiological limits during the experiment, and the tissue pressure method and autoperfusion is to be preferred.
α 2–Adrenoceptor activation may trigger the increased production of endothelium–derived nitric oxide in skeletal muscle during acute haemorrhage
Authors: EKELUND  , BJÖRNBERG  , MELLANDER
Published: March 2003

Our previous studies indicated that acute haemorrhage leads to a pronounced increase in the release of endothelium‐derived nitric oxide (EDNO) graded in relation to the magnitude of the blood loss. The EDNO‐induced vasodilatation, confined selectively to the arterial `feeder' vessels, attenuates the concomitant reflex adrenergic constriction and thereby prevents deleterious reduction of blood flow. The present study aimed at investigating whether the reflex release of blood‐borne catecholamines might trigger this EDNO release via activation of endothelial α2‐adrenoceptors. The study was performed on the sympathectomized vascular bed of cat skeletal muscle with a technique permitting quantitative recordings of resistance (tone) in consecutive vascular sections. Selective α2‐adrenoceptor blockade with idazoxan applied at steady state vasoconstriction after a 35% blood loss evoked an initial generalized dilator response (attributable to inhibition of post‐synaptic smooth muscle α2‐adrenoceptors), followed by a constrictor response selectively in the arterial feeder vessels, the latter compatible with the hypothesis of reduced EDNO release by α2‐adrenoceptor blockade. More direct evidence for the hypothesis was obtained from studies of the vascular response to EDNO blockade (
L‐NAME) after haemorrhage in the presence and absence of α2‐adrenoceptor blockade. The constrictor response to EDNO blockade, which is a measure of the pre‐existing EDNO dilator influence (EDNO production), was significantly smaller (P < 0.01) in the presence than absence of α2‐adrenoceptor blockade. The results indicate that blood‐borne catecholamines, via activation of endothelial α2‐adrenoceptors, trigger the increase in the EDNO release in acute haemorrhage, implying a functionally important negative feedback in the integrated control of vascular tone in bleeding.
Myosin phosphatase: subunits and interactions
Authors: HARTSHORNE
Published: March 2003

Myosin phosphorylation is an important mechanism in regulating contractile activity of smooth muscle. The level of myosin phosphorylation depends on the balance of two enzymes, myosin light chain kinase and myosin phosphatase. Recently it has been discovered that myosin phosphatase can be regulated and this renewed interest in characterization of the phosphatase. It is suggested that the myosin phosphatase is composed of three subunits: a catalytic subunit of type 1 phosphatase (δ isoform; PP1cδ); and two non‐catalytic subunits, large and small (M20). The large subunit is thought to be a targeting subunit and is termed myosin phosphatase target subunit (MYPT). There are several isoforms of MYPT and two genes have been identified on human chromosomes 1 and 12. A dominant feature of MYPT is a series of ankyrin repeats at the N‐terminal end of the molecule and these may be involved in binding to the catalytic subunit and to substrate, phosphorylated myosin. In addition, at the N‐terminal fringe of the ankyrin motifs is a consensus PP1c binding motif. The function of the M20 subunit is not established but is known to bind to the C‐terminal end of MYPT. Various interactions between subunits that might be relevant for the regulation of phosphatase activity are discussed.
Volume‐activated taurine efflux from the in situ perfused lactating rat mammary gland
Authors: CALVERT  , SHENNAN
Published: March 2003

The effect of cell swelling on the efflux of amino acids from the in situ perfused lactating rat mammary gland has been examined. Cell swelling, induced by a hyposmotic shock, increased the fractional release of [3H]taurine. In contrast, a hyposmotic shock did not stimulate the efflux of
D‐[3H]aspartate, suggesting that the effect of a hyposmotic challenge on taurine release cannot be attributed to cell lysis. Volume‐activated taurine efflux was reversible, dependent upon the extent of the osmotic challenge and inactivated with a prolonged hyposmotic shock. The release of taurine was also reversibly increased following isosmotic cell swelling (using urea). The results confirm the presence of a volume‐sensitive taurine efflux transport system in lactating rat mammary tissue and suggest that the volume‐activated amino acid efflux pathway is located at the blood‐facing aspect of the mammary epithelium.
Middle cerebral artery blood velocity depends on cardiac output during exercise with a large muscle mass
Authors: IDE  , POTT  , LIESHOUT J.J. VAN , SECHER
Published: March 2003

We tested the hypothesis that pharmacological reduction of the increase in cardiac output during dynamic exercise with a large muscle mass would influence the cerebral blood velocity/perfusion. We studied the relationship between changes in cerebral blood velocity (transcranial Doppler), rectus femoris blood oxygenation (near‐infrared spectroscopy) and systemic blood flow (cardiac output from model flow analysis of the arterial pressure wave) as induced by dynamic exercise of large (cycling) vs. small muscle groups (rhythmic handgrip) before and after cardioselective β1 adrenergic blockade (0.15 mg kg−1 metoprolol i.v.). During rhythmic handgrip, the increments in systemic haemodynamic variables as in middle cerebral artery mean blood velocity were not influenced significantly by metoprolol. In contrast, during cycling (e.g. 113 W), metoprolol reduced the increase in cardiac output (222 ± 13 vs. 260 ± 16%), heart rate (114 ± 3 vs. 135 ± 7 beats min−1) and mean arterial pressure (103 ± 3 vs.112 ± 4 mmHg), and the increase in cerebral artery mean blood velocity also became lower (from 59 ± 3 to 66 ± 3 vs. 60 ± 2 to 72 ± 3 cm s−1; P < 0.05). Likewise, during cycling with metoprolol, oxyhaemoglobin in the rectus femoris muscle became reduced (compared to rest; −4.8 ± 1.8 vs. 1.2 ± 1.7 μmol L−1, P < 0.05). Neither during rhythmic handgrip nor during cycling was the arterial carbon dioxide tension affected significantly by metoprolol. The results suggest that as for the muscle blood flow, the cerebral circulation is also affected by a reduced cardiac output during exercise with a large muscle mass.
Increase in nitric oxide formation after chronic voluntary exercise in spontaneously hypertensive rats
Authors: JONSDOTTIR  , JUNGERSTEN  , JOHANSSON  , WENNMALM  , THORÉN  , HOFFMANN
Published: March 2003

The effect of chronic voluntary exercise on the plasma level of nitrate, a major stable metabolite of nitric oxide (NO) was studied in spontaneously hypertensive rats (SHR). Exercise consisted of spontaneous running in wheels for 3–35 days. Blood samples were collected after 3, 7, 14, 21 and 35 days of exercise and all samples were drawn after the running wheel had been locked during the preceding 12 h. The plasma nitrate level was significantly (P < 0.05) elevated in SHR after 35 days of exercise. Surprisingly after 7 days of exercise a significant (P < 0.001) decrease in the nitrate level in plasma was noted. Further research is needed to elucidate this biphasic change in nitrate seen in this study. The elevated level of plasma nitrate seen after 35 days of voluntary exercise was still present up to 36 h after termination of exercise. We conclude that exercise training in SHR elicits an enhanced formation of NO.
Glomerular charge selectivity for proteins larger than serum albumin as revealed by lactate dehydrogenase isoforms
Authors: LINDSTRÖM  , JOHNSSON  , HARALDSSON
Published: March 2003

It is well known that macromolecules like albumin are markedly restricted in their passage across the glomerular capillary wall. However, the relative importance of solute size, charge and shape is currently debated since much of the previous work is based on dextran in neutral or charge‐modified forms. These polymers have certain drawbacks that make them less suitable for analysis of capillary permeability and the notion of a glomerular charge barrier has therefore been questioned. Moreover, macromolecules larger than albumin (mol. wt. 69 000) have been suggested to pass through nonselective 'shunt' pathways. In order to study glomerular permeability, isolated rat kidneys were perfused with albumin solutions containing trace amounts of two differently radiolabelled isoenzymes of lactate dehydrogenase (LDH) at low temperature to inhibit tubular function. The isoenzymes have similar size (mol. wt. 140 000) and shape but differ in charge, one carrying a negative net surface charge (LDH1, − 19) and the other being slightly cationic (LDH5, + 2). The urine and perfusate samples were subjected to high pressure liquid chromatography (HPLC) gel‐filtration to allow for measurements of intact LDH. The fractional clearance was 0.11% ± 0.04% for the anionic LDH1 and 0.56% ± 0.07% for LDH5, whereas that for albumin was 0.21% ± 0.03% at a glomerular filtration rate of 0.11 ± 0.01 mL min−1 g−1 kidney wet weight. The results were analysed using a homogenously charged membrane model and are compatible with a charge density of 35 mEq L−1, with 95% confidence interval of 26–41 mEq L−1. These findings suggest a significant glomerular charge selectivity for proteins substantially larger than albumin. The charge density is, however, far less than estimated from dextran studies.
Endogenous muscarinic activity attenuates adrenergic inotropic effects in field stimulated atrial myocardium from children with congenital heart defects
Authors: BORTHNE  , LANGSLET  , LINDBERG  , OSNES  , SKOMEDAL
Published: March 2003

To analyse the possible influence of endogenous muscarinic activity on the inotropic effects of endogenously released noradrenaline in field stimulated myocardial preparations from atria of children with congenital heart defects, we studied the maximal effect of the muscarinic antagonist atropine (1.5 μmol L−1). Maximal force of contraction increased by 12.8 ± 2.0% (SEM), while the maximal rate of development of the force increased by 16.7 ± 2.7% (SEM). Time to half maximal developed force was 57 ± 5 s (SEM). Time to peak force, time to relax to the 20% level and relaxation time all decreased significantly after atropine. Compared with endogenous adrenoceptor stimulation alone, the combined effects of partial muscarinic and adrenergic receptor stimulation thus were moderate reductions of the maximal force of contraction and maximal rate of development of the force and increased time to peak force, time to relax to the 20% level and relaxation time. The main effect of the endogenous muscarinic activity probably was to attenuate the effect of the β‐adrenoceptor stimulation. The endogenous muscarinic activity in field stimulated atrial preparations from children is significant, and has to be taken into account in experimental set‐ups.
C‐peptide potentiates the vasoconstrictor effect of neuropeptide Y in insulin‐dependent diabetic patients
Authors: JOHANSSON  , PERNOW
Published: March 2003

Recent findings suggest that proinsulin C‐peptide improves renal and nerve function as well as microcirculation in patients with insulin‐dependent diabetes possibly by stimulating Na−K+‐ATPase activity. Furthermore, in vitro studies on proximal rat renal tubule cells show that the effect of C‐peptide on Na+, K+‐ATPase activity is potentiated in the presence of the vasoconstrictor peptide neuropeptide Y. The aim of the present study was to examine whether the effects of neuropeptide Y on resting forearm blood flow in insulin‐dependent patients is altered in the presence of C‐peptide. Forearm blood flow was measured by a plethysmographic method in eight insulin‐dependent patients and six healthy control subjects. Neuropeptide Y (20, 200 and 2000 pmol min−1) was infused into the brachial artery before and during an i.v. infusion of C‐peptide (5 pmol kg−1 min−1). Basal blood flow was 36.7 ± 2.2 mL min−1 L−1 tissue. It decreased in a dose dependent manner by 11 ± 2, 18 ± 3 and 25 ± 3%, respectively, during infusion of neuropeptide Y. Administration of C‐peptide increased basal blood flow by 25 ± 6%, to 46.3 ± 3.5 mL min−1 L−1 tissue (P < 0.01) and forearm glucose uptake by 76 ± 34% (P < 0.05). Infusion of the three doses of neuropeptide Y during administration of C‐peptide decreased forearm blood flow by 14 ± 4, 22 ± 3 and 42 ± 4%. There was a significant difference (43%, P < 0.001) between the reduction in blood flow evoked by the high dose (2000 pmol min−1) of neuropeptide Y before and during C‐peptide infusion. Similar differences were also obtained when data were calculated as changes in vascular resistance. C‐peptide did not affect resting forearm blood flow or the response to neuropeptide Y in healthy controls. In conclusion, the present data demonstrate that C‐peptide increases resting forearm blood flow and augments the vasoconstrictor effects of neuropeptide Y in insulin‐dependent patients.
Mechanisms of impaired urinary concentrating ability in adult rats treated neonatally with enalapril
Authors: GURON  , NILSSON  , NITESCU  , NIELSEN  , SUNDELIN  , FRØKIÆR  , FRIBERG
Published: March 2003

Neonatal angiotensin‐converting enzyme inhibition or angiotensin II type‐1 receptor blockade induces irreversible renal histological abnormalities and an impaired urinary concentrating ability in the rat. The aim of the present study was to determine the pathophysiological mechanisms underlying the defect in urine concentration in adult rats treated neonatally with enalapril. Male Wistar rats received daily intraperitoneal injections of enalapril (10 mg kg−1) or saline vehicle from 3 to 24 days of age. Assessments of fluid handling and maximal urine osmolality (Uosmmax), renal function and tubular free water reabsorption (TcH2O) under pentobarbital anaesthesia, renal tissue solute concentrations, renal aquaporin‐2 (AQP2) expression, and kidney histology, were performed in 12–16‐week‐old rats. Uosmmax (1488 ± 109 vs. 2858 ± 116 mosm kg−1, P < 0.05) and maximal TcH2O were reduced in enalapril‐ vs. vehicle‐treated rats after administration of 1‐desamino‐8‐
D‐arginine vasopressin. Neonatally enalapril‐treated rats showed marked papillary atrophy, a decrease in medullary tissue solute concentrations, and a reduction in AQP2 expression specifically in the inner medulla. Glomerular filtration rate, renal plasma flow and urinary excretion rates of sodium, potassium and chloride did not differ between groups. In conclusion, adult rats treated neonatally with enalapril showed a urinary concentrating defect of renal origin which primarily could be explained by the papillary atrophy. However, an impaired ability to generate medullary interstitial hypertonicity, and a decrease in inner medullary AQP2 expression, also seem to contribute to this defect.
Minor redistribution of ventilation and perfusion within the lung during exercise in sheep
Authors: MELSOM  , FLATEBØ  , SJAASTAD  , AULIE  , NICOLAYSEN
Published: March 2003

Considerable heterogeneity unrelated to the effect of gravity has been demonstrated for both local ventilation (V˙) and perfusion (Q˙) in the lung. Local ventilation and perfusion are well matched, so that the heterogeneity of the V˙/Q˙ ratio is less than for ventilation or perfusion alone (
Melsom et al. 1997
). We are searching for the mechanisms responsible for the coordinate heterogeneity of ventilation and perfusion. Here, we ask how and to what extent physical exercise induces changes in the distribution of ventilation and perfusion. We measured local (≈1.5 cm3 tissue volume) pulmonary ventilation and perfusion simultaneously in six sheep before, during and after running on a treadmill. Local ventilation was determined from the deposition of labelled aerosol particles and local perfusion from trapping of radioactive microspheres. Cardiac output increased ≈2.5‐fold during exercise. V˙/Q˙‐ratios were not normally distributed and we therefore present the heterogeneity as the interquartile range. At rest, the average interquartile ranges for local ventilation, perfusion and V˙/Q˙‐ratio were 0.48, 0.51 and 0.39, respectively. During exercise, the corresponding values were 0.44, 0.40 and 0.32. Thus, the distribution of local V˙/Q˙‐ratio was narrower than for ventilation and perfusion also during exercise. We found a moderate redistribution of relative flow towards the dorsal parts of the lungs when perfusion increased, but the increase in total perfusion and ventilation was for the most part throughout the lung. The results indicate that the coupling between local ventilation and perfusion is at least as potent during exercise as at rest. The correlation (r) between paired values in the two resting periods was 0.93 for ventilation and 0.91 for perfusion and thus indicates time stability for the two variables.
Telemetric registration of heart rate and blood pressure in the same unrestrained goats during pregnancy, lactation and the non‐pregnant, non‐lactating period
Authors: HYDBRING  , CVEK  , OLSSON
Published: March 2003

The purpose of this study was to investigate how changes in heart rate and arterial blood pressure relate to the time of day, reproductive period and feeding routines in dairy goats (Capra hircus). Registrations were made by radiotelemetry in the same four goats during pregnancy, lactation and the non‐pregnant, non‐lactating (dry) period. Heart rate rose around the morning and afternoon feedings, whereas blood pressure did not show any diurnal rhythm. Comparison between reproductive periods revealed that heart rate was higher during the fifth month of pregnancy than during lactation and the dry period, whereas for blood pressure no such differences between periods were found. Withholding three meals from lactating goats resulted in a continuous slowdown of the heart rate, whereas blood pressure fluctuated. Re‐feeding temporarily increased the heart rate but had no effect on blood pressure which continued to fluctuate. After another 2 days, blood pressure (but not heart rate) had stabilized. Food‐restriction, aimed at terminating milk production resulted in a consistently depressed heart rate and reduced the mean and systolic blood pressures at night. The results show that with this implantable telemetry device it is possible to measure both heart rate and blood pressure day and night in the same unrestrained animals over a length of time long enough to include all reproductive periods. Our results emphasize that when planning experiments it is important that the exact stage in each reproductive period, the act of feeding and the amount of food given be taken into account.
Regulation of glycogen breakdown by glycogen level in contracting rat muscle
Authors: VANDENBERGHE  , RICHTER  , HESPEL
Published: March 2003

The interaction of glycogen concentration, insulin and β‐adrenergic stimulation in the regulation of glycogen breakdown was studied in perfused rat muscles. Rats were pre‐conditioned to obtain two groups with either normal (N) or `supercompensated' (SC) muscle glycogen. The next day their hindlimbs were perfused with a medium containing insulin (0, 40 and 100 μU mL−1) and/or isoproterenol (0 and 1.5 nmol L−1). Contractions were induced by electrical stimulation of the sciatic nerve. Compared with N, glycogen breakdown in white gastrocnemius during contractions was greater in SC at any hormonal combination (P < 0.05). Conversely, in red gastrocnemius (RG) the higher glycogenolytic rate in SC, compared with N, faded as the insulin concentration was raised from 0 to 100 μU mL−1. However, isoproterenol restored the higher glycogenolytic rate in SC. In any condition, RG glycogen synthase fractional activity was lower (P < 0.05) during contractions in SC than in N. Furthermore, the percentage of phosphorylase a was higher in SC except when muscles were exposed to insulin alone. In conclusion, high initial glycogen concentration in fast‐glycolytic muscle causes high glycogenolytic rate during contractions, irrespective of hormonal stimulation. In contrast, due to down‐regulation of phosphorylase activity, such a relationship does not exist in insulin‐stimulated fast‐oxidative muscle.
Effects of age, sex and physical exercise on the phagocytic process of murine peritoneal macrophages
Authors: Ferrandez  , Fuente
Published: March 2003

Different stages of the phagocytic process, i.e. chemotaxis, ingestion of latex beads and superoxide anion production, were measured in peritoneal macrophages from young (12 ± 2 weeks old) and old (60 ± 2 weeks old) male and female BALB/C mice, which were subjected to an acute bout of exercise (swimming until exhaustion) or to a period of training exercise (90 min of swimming each day during 20 days). Sedentary male and female mice as well as young and old animals were used as sex and age controls. The results show that both acute and training exercise stimulate the phagocytic process of murine peritoneal macrophages. The macrophage functions from sedentary controls were lower in the old than in the young animals. The chemotaxis and ingestion capacities of macrophages were higher in the female young and old sedentary mice than in their male counterparts. After exercise, the stimulation of the phagocytic process was higher in old and female mice than in young and male animals. In addition, serum corticosterone levels were measured in order to investigate the relations between stress and macrophage activity. Old and female mice as well as animals subjected to exercise showed, in general, higher corticosterone levels than young, male and sedentary animals.
Hypoxia and hyperoxia both transiently affect distribution of pulmonary perfusion but not ventilation in awake sheep
Authors: Melsom  , Flatebø  , Nicolaysen
Published: March 2003

Despite a remarkable gravity independent heterogeneity in both local pulmonary ventilation and perfusion, the two are closely correlated at rest and during exercise in the normal lung. These observations strongly indicate that there is a mechanism for coupling of the two so that local V˙/Q˙‐ratio is kept fairly uniform throughout the lung. This is also necessary to achieve adequate gas exchange in the lung. It was recently suggested that oxygen‐induced vasoconstriction has a slow and intense component that might contribute to the matching of ventilation and perfusion also under normal conditions (
Vejlstrup & Dorrington 1993). We therefore simultaneously determined distribution of local (≈ 1½ cm3 lung pieces) ventilation and perfusion in eight sheep at normoxia (FiO2 21%) and after 10 min and 2½ h exposure to hypoxia (FiO2 12%; four sheep) or hyperoxia (FiO2 40%; four sheep). We used a ≈ 1 μm wet fluorescent aerosol and 15 μm radioactive microspheres i.v. to measure local ventilation and perfusion, respectively. Neither hypoxia nor hyperoxia caused changes in the distribution of ventilation. After 10 min exposure to hypoxia or hyperoxia, distribution of perfusion was altered so that the correlation between values for local ventilation and perfusion decreased. After 2½ h exposure to either hypoxia or hyperoxia, distributions of perfusion and v˙/Q˙‐ratio had returned to baseline. These results show that distribution of perfusion is influenced by acute changes in oxygen tension, so that local matching of ventilation and perfusion is affected. Apparently, some mechanism restores the matching during extended exposure to the altered oxygen tension.
Cholinergic induced mesenteric vasorelaxation in response to head‐up tilt
Authors: Perko M.J. , Madsen P. , Perko G. , Schroeder T.V. , Secher N.H.
Published: March 2003

Central hypovolaemia induced by head‐up tilt evokes a reduction in superior mesenteric artery resistance resulting in maintenance of regional blood flow. Mechanisms of importance for this response are not known, but a parasympathetic contribution could be expected. To evaluate this hypothesis, superior mesenteric artery blood flow and resistance were evaluated by duplex ultrasound in eight healthy volunteers during postprandial head‐up tilt with and without cholinergic blockade. During supine rest, cholinergic blockade did not influence the postprandial reduction in peripheral mesenteric artery resistance as expressed by analogous elevations in the diastolic blood velocity (to 62 ± 9 vs. 56 ± 7 cm s–1 with placebo). Throughout the normotensive and hypotensive phases of head‐up tilt, cholinergic blockade reduced mesenteric artery mean blood velocity by 39 and 42%, respectively, corresponding to volume flow reductions by 35 and 41% (0.62 ± 0.10 vs. 0.96 ± 0.13 L min–1 and 0.52 ± 0.07 vs. 0.88 ± 0.16 L min–1; P < 0.05). Also, during both phases of head‐up tilt, cholinergic blockade increased mesenteric artery resistance as reflected in a reduction in the diastolic blood velocity by 41 and 56%, respectively (44 ± 4 vs. 74 ± 13 cm s–1 and 24 ± 6 vs. 54 ± 8 cm s–1). These results support a cholinergic contribution to the mesenteric artery vasorelaxing response to central hypovolaemia induced by head‐up tilt.
Attenuated insulin action on glucose uptake and transport in muscle following resistance exercise in rats
Authors: Fluckey  , Ploug  , Galbo
Published: March 2003

A previous study reported elevations of insulin‐mediated muscle protein synthesis following four days of resistance exercise in rats (Fluckey et al. 1996. Am J Physiol270, E313–E319). The purpose of this study was to determine if insulin‐stimulated muscle glucose uptake (a–v diff.) and 2‐deoxyglucose (2‐DG) transport were altered under similar conditions. The protocol consisted of squat‐like exercises during four sessions with progressively increased weight (70–190 g). Each session consisted of 50 repetitions and sessions were separated by 48 h. Sixteen hours after the last exercise session, basal glucose uptake in perfused hindlimbs was not different (P > 0.05) between exercised (n=6) and non‐exercised controls (n=6). However, there was a significant (P < 0.05) attenuation of insulin‐stimulated (20 000 μU mL–1) glucose uptake in exercised vs. non‐exercised rats (491 ± 31 vs. 664 ± 58 μmol glucose–1 g–1 [15‐min insulin period]–1, respectively). Following resistance exercise, insulin‐stimulated 2‐DG transport, measured during the last 10 min of the perfusion period, was significantly reduced (P < 0.05) in the soleus, white gastrocnemius and extensor digitorum longus muscles. Additionally, GLUT‐4 glucose transporter protein content was significantly reduced (P < 0.05) in white gastrocnemius and extensor digitorum longus muscles. These results demonstrate that insulin‐stimulated glucose uptake and transport are reduced after resistance exercise. Furthermore, the applied resistance exercise protocol causes directionally opposite changes of insulin action in two major metabolic pathways, i.e. glucose transport and protein synthesis.
Mechanisms associated with hypoxia‐ and contraction‐mediated glucose transport in muscle are fibre‐dependent
Authors: Fluckey  , Ploug  , Galbo
Published: March 2003

The purpose of this study was to examine the effects of hypoxia and muscle contractions on rates of 2‐deoxyglucose (2‐DG) transport in red and white portions of the gastrocnemius muscle of the rat. 2‐DG transport was measured during the last 10 min of a 60‐min hindlimb perfusion in male Wistar rats (≈ 300 g), with or without muscle contractions of one limb. The medium was gassed with either 95% oxygen and 5% carbon dioxide or 95% nitrogen and 5% carbon dioxide to achieve normal or hypoxic conditions, respectively. Muscle contractions began after 30 min of perfusion and consisted of isometric muscle actions (200‐ms trains, 100 Hz; one train per second) for two sets of 5 min, with 1‐min rest between sets. 2‐DG transport in white gastrocnemius was higher (P < 0.05) than basal during hypoxia (4.8‐fold) and following contractions using oxygenated or hypoxic medium (4.6‐fold and 5.4‐fold, respectively; n=6 for each group). 2‐DG transport was not different (P > 0.05) between these stimulated conditions. Similarly, 2‐DG transport in red gastrocnemius was 5.1‐ and 4.8‐fold higher (P < 0.05) than basal during hypoxia and following contractions in oxygenated medium, respectively. However, 2‐DG transport following contractions during hypoxic conditions in red gastrocnemius was, unlike white gastrocnemius, higher (8.9‐fold over basal; P < 0.05) than in all other conditions. These results suggest that mechanisms associated with hypoxia‐ and muscle contraction‐mediated glucose transport are fibre type‐dependent, with additive effects of the two stimuli in fast‐twitch, oxidative fibres.
Pituitary adenylate cyclase‐activating polypeptide inhibits the cyclooxygenase pathway of rat cerebral microvessels
Authors: Kis  , Gáspár  , Mezei  , Gecse  , Telegdy
Published: March 2003

The presence of nerve endings containing pituitary adenylate cyclase‐activating polypeptide (PACAP) and vasoactive intestinal polypeptide (VIP) around cerebral microvessels suggests that these peptides have regulatory roles in the cerebral microcirculation. Prostanoids synthesized by the cerebrovascular endothelium have a determining role in the regulation of the brain circulation. In the present study, the effects of PACAP and VIP on the cyclooxygenase pathway of cerebral microvessels were investigated. The isolated microvessels were incubated with 1‐14C‐arachidonic acid and different concentrations of the peptides. The prostanoids formed were separated by means of overpressure thin‐layer chromatography, and were quantitatively determined by liquid scintillation. Higher concentrations (10–7 and 10–6 mol L–1) of PACAP significantly inhibited the activity of the cyclooxygenase pathway, whereas VIP had no significant effect on it. As regards the cyclooxygenase metabolites, the syntheses of thromboxane A2 and prostaglandin D2 were inhibited significantly. PACAP and VIP are known to increase the intracellular cAMP level in the cerebral microvessels and in the present experiments the protein kinase A inhibitor H‐89 attenuated the effect of PACAP on prostanoid synthesis. It is concluded that the cyclooxygenase pathway of rat cerebral microvessels is more sensitive to PACAP than to VIP. The inhibitory effect of PACAP on prostanoid synthesis is mediated via a cAMP‐dependent pathway. By inhibiting the formation of vasoactive prostanoids, PACAP can decrease the vasoreactivity of the microvessels.
Reduced short and long latency reflexes during voluntary tracking movement of the human wrist joint
Authors: Bawa  , Sinkjær
Published: March 2003

In six healthy human subjects we compared changes in the strength of Hoffmann (H), short latency (30–55 ms) and long latency (55–100 ms) stretch reflexes of flexor carpi radialis (FCR) muscle during movement and isometric contractions. In one set of experiments, stretches were imposed to the wrist during voluntarily tracked sinusoidal movement and during matched isometric contractions to compare short and long latency stretch reflex responses. In the second set, H‐reflexes were compared during similar matched conditions. All reflexes decreased significantly (P < 0.05) during the voluntary tracking movement. The H‐reflex was reduced during the wrist flexion, on average, by 33% of its value obtained during the isometric condition. Compared with their values during isometric conditions, the short latency stretch reflex and long latency stretch reflex during movement were reduced by 52 and 40%, respectively. From the pattern changes of the stretch reflexes and the H‐reflex, a movement‐induced presynaptic inhibition combined with pronounced muscle spindle unloading is proposed to play an important role in decreasing the strength of the stretch reflexes during the tracking task as compared with a matched isometric contraction.