Acute hypoxia blunts cold sensitivity through the inhibition of the lateral parabrachial nucleus in rats / 生理学报

To explore the changes of cold sensitivity after exposure to acute hypoxia and its mechanisms, Sprague-Dawley rats were divided into normoxia control group (21% O2, 25 °C), 10% O2 hypoxia group (10% O2, 25 °C), 7% O2 hypoxia group (7% O2, 25 °C), normoxia cold group (21% O2, 10 °C) and hypoxia cold group (7% O2, 10 °C). Cold foot withdrawal latency and preference temperature of each group were measured, skin temperatures were estimated using an infrared thermographic imaging camera, body core temperature was recorded by wireless telemetry system, immunohistochemical staining was used to detect the expression of c-Fos in the lateral parabrachial nucleus (LPB). The results showed that acute hypoxia significantly prolonged the latency of cold foot withdrawal and significantly enhanced the intensity of cold stimulation for foot withdrawal, and the rats under hypoxia preferred cold temperature. Cold exposure (10 °C) for 1 h significantly enhanced the expression of c-Fos in LPB of rats in normoxia, while hypoxia inhibited cold-induced c-Fos expression. Acute hypoxia significantly increased the skin temperature of feet and tails, decreased the skin temperature of interscapular region, and decreased the body core temperature of rats. These results indicate that acute hypoxia can significantly blunt cold sensitivity through the inhibition of LPB, suggesting actively keeping warm measures should be taken at the early stage after ascent to high altitude to prevent the upper respiratory infection and acute mountain sickness.

Clinicopathological analysis of 155 patients with persistent isolated hematuria / 中国医学科学杂志(英文版)

<p><b>OBJECTIVES</b>To reveal etiologies of persistent isolated hematuria (PIH) through ultrastructural pathological examination, to disclose clinicopathological correlation in cases with PIH, and to summarize appropriate management of patients with PIH.</p><p><b>METHODS</b>we retrospectively studied 155 PIH patients receiving renal biopsy between January, 2003 and December, 2008 in Peking Union Medical College Hospital. All the clinical data and follow-up result were analyzed.</p><p><b>RESULTS</b>All subjects included 38 children and 117 adults, with mean age of 11.38±3.25 years for children and 35.17±8.44 years for adults. Thin basement membrane nephropathy (TBMN) was the most common pathology (55.3% of children and 49.6% of adults), followed by IgA nephropathy (18.4% of children and 32.5% of adults, mainly grade 2-3) and mesangial proliferative glomerulonephritis (MsPGN) without IgA deposition (13.2% of children and 12.8% of adults). Besides, Alport syndrome (2.6% of children) and membrane nephropathy (2.6% of children and 0.9% of adults) were demonstrated as other causes of PIH. Elevated mean arteral pressure or protein excretion rate, as well as episodic macrohematuria, indicated higher risk for MsPGN rather than TBMN. On the other hand, severity of microhematuria was irrelevant to pathological types of PIH. Totally, 86 patients were followed up and 37 cases therein stayed on track for long term (mean duration 41.11?28.92 months, range 8-113 months). Most cases had benign clinical course except 3 cases with TBMN, 5 cases with IgA nephropathy, 1 case with MsPGN (without IgA deposition), and 1 case with Alport syndrome, who developed hypertension or proteinuria. All of them were administered timely intervention.</p><p><b>CONCLUSIONS</b>Close follow-up should be required as the primary management for PIH. Equally important is careful monitoring for early identification of undesirable predictors; while renal biopsy and other timely intervention are warranted if there is hypertension, significant proteinuria or renal impairment.</p>

Application of the Oxford classification of IgA nephropathy to predict renal outcome / 中国医学科学院学报

<p><b>OBJECTIVE</b>To validate the value of the Oxford classification of IgA nephropathy in predicting the renal outcome in Chinese population.</p><p><b>METHODS</b>Retrospective study was done in patients with IgA nephropathy. All slides were re-assessed according to the Oxford classification of IgA nephropathy. The primary end point is doubling serum creatinine, or a 50% reduction in estimated glomerular filtration rate (eGFR), or end-stage renal disease. Pathologic predictors for the progression to the end point were determined by univariate and multivariate Cox regression.</p><p><b>RESULTS</b>Totally 533 patients were enrolled in the study. During the follow-up (median: 39 months; range: 12-263 months), 5.07% of the patients reached the end point. While tubular atrophy and interstitial fibrosis and arterial/ arteriolar lesion were associated with the endpoint in univariate analysis, only the T score was predictive of the renal outcome in multivariate Cox regression. Combination of the patho- logic lesions had no impact on renal outcome.</p><p><b>CONCLUSION</b>According to the Oxford classification of IgA nephropathy, the degree of tubulointerstitial fibrosis is the only feature independently predictive of renal outcome.</p>

Effects of acute hypobaric hypoxia and exhaustive exercise on AMP-activated protein kinase phosphorylation in rat skeletal muscle / 生理学报

The present study was aimed to explore the changes of phosphorylated AMP-activated protein kinase (pAMPK) level in skeletal muscle after exposure to acute hypobaric hypoxia and exhaustive exercise. Thirty-two male Sprague-Dawley (SD) rats were randomly divided into sea level and high altitude groups. The rats in high altitude group were submitted to simulated 5 000 m of high altitude in a hypobaric chamber for 24 h, and sea level group was maintained at normal conditions. All the rats were subjected to exhaustive swimming exercise. The exhaustion time was recorded. Before and after the exercise, blood lactate and glycogen content in skeletal muscle were determined; AMPK and pAMPK levels in skeletal muscle were detected by Western blot. The results showed that the exhaustion time was significantly decreased after exposure to high altitude. At the moment of exhaustion, high altitude group had lower blood lactate concentration and higher surplus glycogen content in gastrocnemius compared with sea level group. Exhaustive exercise significantly increased the pAMPK/AMPK ratio in rat skeletal muscles from both sea level and high altitude groups. However, high altitude group showed lower pAMPK/AMPK ratio after exhaustion compared to sea level group. These results suggest that, after exposure to acute hypobaric hypoxia, the decrement in exercise capacity may not be due to running out of glycogen, accumulation of lactate or disturbance in energy status in skeletal muscle.

The role of hypoxic response and breath holding at sea level in prediction of acute mountain sickness / 中国应用生理学杂志

<p><b>AIM</b>To explore whether hypoxic response and breath holding at sea level could predict acute mountain sickness (AMS).</p><p><b>METHODS</b>113 men aged (19 +/- 1) years took part in this study. Blood oxygen saturation (SaO2), heart rate and blood pressure were measured during the course of breathing 10% O2 for 10 minutes and breath holding. Two days later after reaching Lasa (3 658 m altitude) by air, the symptomatic scores of AMS were evaluated. Then the relations between them were analyzed.</p><p><b>RESULTS</b>The SaO2 reduced progressively and the heart rate speeded up, while the blood pressure represented increase at first and then decrease within 10 min during the short-term hypoxia. The heart rate was lower during short-term hypoxia in subjects who developed AMS than in subjects doing well. But significant reverse correlation existed only between AMS scores and heart rate at 7th min after hypoxic breathing (r = -0.176).</p><p><b>CONCLUSION</b>Limited information can be gained on AMS score by assessing physiological responses to short-term hypoxia and breath holding at sea level.</p>

Effects of acute hypoxia and adenosine on splenic T-lymphocyte proliferation of rats / 中国应用生理学杂志

<p><b>AIM</b>To observe the effects of acute hypoxia and adenosine on splenic T lymphocyte proliferation.</p><p><b>METHODS</b>Wistar rats were divided into control and hypoxic group, and the latter were exposed to hypoxia (5000 m simulated high altitude, 23 h/d). Three days later, spleen cells were collected and stimulated by 5.0 microg/ml and 2.5 microg/ml concanavalin A (ConA) to determine the splenocyte proliferation. The proliferation was also observed after addition of different amount of adenosine to culture medium.</p><p><b>RESULTS</b>Acute hypoxia and adenosine had marked inhibitory effect on mitogenic response to Con A in splenic T cells, and the inhibitory effect induced by adenosine displayed concentration-dependent.</p><p><b>CONCLUSION</b>Acute hypoxia may impair the T cell function and adenosine could be involved in this process.</p>

Effects of hypoxia combined-exercise on blood viscosity and cardiac function of rats / 中国应用生理学杂志

<p><b>AIM</b>To study the effects of hypoxia alone or combined-exercise on blood viscosity and cardiac function of rats.</p><p><b>METHODS</b>22 wistar rats were divided into 3 groups: I normoxic control; II hypoxia and III hypoxia-combined exercise. Rats of II and III groups were subjected to hypobaric hypoxia for 5 weeks (23 h/day). They were first brought to simulated 4 000 m altitude, where rats of the III group were forced to swim for 1 h/day (6 days/week). Then the animals were ascent to 5 000 m. Cardiac function were detected by polygraph, the blood viscosity was assayed by E-viscosimeter, 99mTc radiolabelled frog red blood cell was used to measure the cardiac output.</p><p><b>RESULTS</b>Hypoxia alone caused an increase in blood hematocrit (Hct) and viscosity. Cardiac function of the left and right ventricles, especially +/- dp/dt(max) was also increased. Hypoxia-combined-exercise did not cause further increase in Hct, while the blood viscosity was decreased. Cardiac function increased further in both ventricles and the cardiac output was increased by 20% after hypoxia-combined-exercise.</p><p><b>CONCLUSION</b>During acclimatization to hypoxia, moderate exercise can decrease the blood viscosity and increase the cardiac function. These changes may be advantageous in delivering oxygen to tissues and may be favorable for promoting acclimation to high altitude.</p>

Non-diabetic renal disease in type II diabetes mellitus / 中国医学科学院学报

<p><b>OBJECTIVE</b>Several studies have suggested that non-diabetic renal disease (NDRD) was common among non-insulin dependent diabetes mellitus (NIDDM) patients with renal involvement.</p><p><b>METHODS</b>The prevalence of NDRD among Chinese NIDDM population in PUMC hospital center was retrospectively studied. Renal biopsy specimens were evaluated with light-, immunofluorescence- and electron-microscopy. The cohort consisted of 33 NIDDM patients who received renal biopsy.</p><p><b>RESULTS</b>Patients with both isolated diabetic nephropathy (DN, n = 7) and NDRD (n = 22) had comparable duration of DM, creatinine clearance, serum creatinine, albumin and 24 hours proteinuria, as well as incidences of retinopathy, neuropathy and hypertension. Significantly more patients with NDRD had haematuria (P = 0.030) or non-nephrotic proteinuria (P = 0.016). IgA nephropathy accounted for 40.9% of the NDRD identified.</p><p><b>CONCLUSIONS</b>In this study, haematuria and non-nephrotic proteinuria predicted the presence of NDRD among NIDDM patients complicated with renal disease. IgA nephropathy is the most frequent type of NDRD in Chinese.</p>