Effects of tissue preparation on glomerular volume and capillary structure in the rat

The effect of tissue preparation on glomerular volume in normal rats was assessed. In group 1 rats (N = 8), kidney tissue was obtained by immersion-fixation of needle biopsy cores and excised slices from the left kidney and by perfusion-fixation of the remaining right kidney at close to ambient arterial pressure. In group 2 rats (N = 8), tissue was obtained by kidney perfusion at a supernormal pressure (approximately 165 mm Hg). Studies in group 1 showed that mean glomerular volume (VG) was not different in biopsy cores (1.07 +/- 0.13 x 10(6) mu 3) and in kidney slices fixed by immersion (0.92 +/- 0.09 x 10(6) mu 3). A significantly higher value for VG (1.51 +/- 0.18 x 10(6) mu 3) was obtained in kidneys perfusion-fixed at close to ambient arterial pressure. Morphometric studies showed that reduced VG in immersion-fixed tissue was associated with lowered values for peripheral capillary wall surface area (225 +/- 21 x 10(3) mu 2 versus 159 +/- 27 x 10(3) mu 2, p less than 0.05) and reduced mean capillary radius (4.5 +/- 6 mu versus 2.7 +/- 3 mu, p less than 0.05) compared with perfusion-fixed tissue. The data suggest that glomerular capillaries contract when tissue is immersion-fixed and shows that values for mean peripheral capillary wall surface area/glomerulus and mean glomerular capillary radius obtained in immersion- and perfusion-fixed tissue cannot be directly compared. Studies in group 2 showed that VG was not altered by perfusion at a supernormal pressure (1.40 +/- 0.16 x 10(6) mu 3) as compared with perfusion at ambient pressure (1.51 +/- 0.18 x 10(6) mu 3). Further studies in group 1, however, showed that values for VG obtained in paraffin-embedded tissue were approximately 40% lower than values for VG obtained in methacrylate-embedded tissue from the same kidneys.     

The surface area of sheep cardiac Purkinje fibres

1. Measurements combining the techniques of point counting and line integration were performed on light and electron micrographs of Purkinje fibres from the sheep's heart. The measurements were aimed at determining membrane areas of importance for the cellular electrophysiology of this tissue.2. The mean volume fractions of the cells occupied by various constituents were: myofibrils, 0.234; mitochondria, 0.103; and nuclei, 0.009. The mean volume fraction of the fibres occupied by the interspaces between the tightly packed cells was 0.0023.3. The mean fractions of intercellular surface area occupied by junctional specializations were: nexus, 0.17; desmosome, 0.023; and fascia adherens, 0.014.4. The mean surface to volume ratio of the Purkinje cells and fibres was 0.46 mu(-1) which is 11.5 times the value of the surface to volume ratio of a long right circular cylinder 100 mu in diameter.5. There are two reasons for the increment in the surface to volume ratio of the fibre (when compared to that of a long right circular cylinder 100 mu in diameter): the multicellular composition of the fibres and the extensive folding of the surface of the cells.6. After correction for the intercellular nexal area the surface to volume ratio of a long cylindrical fibre 100 mu in diameter was 0.39 mu(-1), or about 10 times the value for a long right circular cylinder 100 mu in diameter. The surface to volume ratio of the tissue interspaces in the same fibre was 170 mu(-1).7. It was concluded that the total sarcolemmal area in this tissue is great enough so that the specific membrane capacitance could be about 1 muF/cm(2) and the specific membrane resistance 20,000 Omega cm(2).     

c-Jun氨基末端激酶在慢性低O2高CO2大鼠海马损伤中的作用

目的： 探讨c-Jun氨基末端激酶（JNK）在慢性低O2高CO2大鼠海马损伤中的作用。方法：采用慢性低O2高CO2肺动脉高压大鼠模型。30只SD大鼠随机分为正常对照（NC）组、低O2高CO2 2周（2WH）组和低O2高CO2 4周（4WH）组,每组10只。 Morris水迷宫检测行为学,用半定量逆转录-聚合酶链反应（RT-PCR）动态观察海马p-JNK mRNA的转录情况,免疫组织化学法测定p-JNK在海马CA1/CA3区的变化,TUNEL法检测海马CA1/CA3区神经细胞凋亡。结果：与NC组相比,低O2高CO22WH、4WH组大鼠寻找站台的平均逃避潜伏期延长、游泳总距离增加(P<0.01或P<0.05),且4WH组比2WH组潜伏期延长及游泳总距离增加更加明显(P<0.05);NC组大鼠海马仅见少量JNK mRNA及蛋白表达,低O2高CO2各组较NC组JNK表达明显增加（P<0.01或P<0.05）,且4WH组比2WH组增加更明显(P<0.05)。低O2高CO22WH、4WH组的TUNEL阳性细胞数均明显多于NC组（P<0.01或P<0.05）,且4WH组比2WH组增多明显（P<0.01）。结论：低O2高CO2能导致大鼠学习记忆障碍,可能与激活海马神经细胞内JNK有关。     

A quantitative morphological study of the carotid bodies of rats living at a simulated altitude of 4300 metres.

A quantitative histological study was carried out on the carotid bodies of 10 normal rats and 10 rats living in a hypobaric chamber at a pressure of 460 mm Hg from 25 to 96 days. In the chronically hypoxic rats there was a four-fold increase in the mean combined volume of the carotid bodies. Morphometric analysis disclosed a three-fold increase in the mean volume of specialised glomic cells and a ten-fold increase in the mean volume of capillaries, although the proportion of glomic cells was actually significantly decreased. In all our hypoxic rats there was evidence of both right and left ventricular hypertrophy. However, there was no linear relation between total carotid body volume or volume of glomic cells on one hand and the right and left ventricular weight, on the other hand. Although there was no linear relation between combined total carotid body volume and duration of hypoxia, the linear relation between glomic cell volume and duration of hypoxia was significant at the 5 per cent. level. The increase in vascularity of the hypoxic carotid body may be a mechanism to increase blood flow and thus oxygen transport to a hypoxic organ with increased metabolic activity. Small quantities of an amorphous hyaline material of unknown nature were found in relation to capillaries and type I cells in all the hypoxic rats.     

A quantitative study of some ultrastructural features of the type I cells in the carotid bodies of rats living at a simulated altitude of 4300 metres

Summary A quantitative study was carried out on the ultrastructure of the type I cells of the carotid bodies of three normal rats and three rats living in a hypobaric chamber at an atmospheric pressure of 460 mm Hg for 27, 28 and 35 days. Point-counting methods were performed on electron micrographs of randomly selected cross-sections of type I cells. These sections always included the nucleus of the cell. The same electron micrographs were used to determine the number of mitochondrial cross-sections and electron-dense core vesicles appearing in each type 1 cell profile. The morphometric analysis disclosed that the mean cross-sectional area of the type I cells was 41.35 m³ in the untreated rats and 82.03 m³ in the rats exposed to chronic hypoxia. Assuming that this area of cross-section was in direct proportion to the volume of the cell, this result indicates an approximately three-fold increase in volume of the type I cells of the carotid bodies in hypoxaemic rats. There was no change in the volume proportion of the type I cells occupied by the mitochondria. However, as the cells had increased in volume in hypoxaemic rats, it was concluded that the number of mitocondria in each type I cell was increased. The concentration of electron-dense core vesicles was 21.9/m³ cytoplasm in the type I cells of untreated rats and 7.3/m³ in the hypoxaemic rats. The dense-core vesicles were increased in diameter in states of chronic hypoxia. Their mean diameter was 102.3 nm in normal rats and 117.0 nm in hypoxaemic rats. The enlargement of the type I cells and the increase in the number of mitochondria within each cell suggests that this depletion is more likely to be due to an increased rate of release of dense-core vesicles, than to a reduced rate of their synthesis.     

Expression of Splice Variants of Insulin-Like Growth Factor I and the State of the Myosatellite Cell Pool in the Soleus Muscle in Rats during Gravitational Unweighting and Passive Stretching

Gravitational unweighting is known to induce atrophy and to suppress proliferative processes in the postural muscles; muscle stretching during unweighting allows this atrophy to be overcome. It has been suggested that stretching of the soleus muscle promotes proliferation of satellite cells with subsequent incorporation of their nuclei into fibers on functioning loading of the hindlimbs in rats. The numbers of satellite cells labeled with M-cadherin on cross-sections of single fibers were assessed. After two weeks of antiorthostatic suspension, the number of labeled cells decreased by 33% from the level seen in the control group. In passive stretching, the number of labeled cells was 2.5 times greater than that in suspended animals and 1.7 times greater than in that control animals. The key role in the activation of satellite cells is known to be played by growth factors, including insulin-like growth factor I (IGF-I). Levels of IGF-I expression were measured in the soleus muscle after suspension with stretching, which showed no changes as compared with the suspension without stretching or control groups. Thus, these experiments demonstrated that passive stretching stimulates increases in the proliferation of satellite cells in the soleus muscle of the stretched limb in rats as compared with the level seen in normal conditions, with no changes in the expression of IGF-I or its splice variant MGF.     

Silica-induced hypertrophy of type II cells in the lungs of rats

Several investigators have reported the appearance of hypertrophic type II cells in the lungs of silica-treated rats. The purpose of this study was to isolate and characterize these hypertrophic type II cells. Lungs were digested with trypsin and the released cells were separated by using a flow gradient during centrifugal elutriation. Type II cells from control lungs were distributed in the flow gradient as a single population, whereas type II cells from the lungs of silica-treated rats had a bimodal distribution suggesting the presence of two distinct populations of type II cells; one of these populations appeared hypertrophic (type IIB) and the other appeared normal (type II cells; one of these populations appeared hypertrophic (type IIB) and the other appeared normal (type IIA). These two populations of type II cells from silica-treated rats differed significantly in cell size and their lamellar body content. The mean volume of type IIA and type IIB cells was 350 +/- 38 micron 3 and 523 +/- 29 micron 3, respectively. The mean number of lamellar bodies in type IIA and type IIB cells was 77 +/- 53 and 131 +/- 84 per cell, respectively. The mean volume of lamellar bodies was 0.39 +/- 0.09 micron 3 in type IIA cells and 0.66 +/- 0.10 micron 3 in type IIB cells. Type IIA cells were not significantly different from type II cells from the lungs of untreated rats. The distribution of type II cells from silica-treated lungs was such that 2 weeks after a single intratracheal injection of silica (10 mg/rat) type IIB cells accounted for 39.2 +/- 6.4% of the total type II cells recovered after centrifugal elutriation. The general morphological appearance of the isolated type IIA and type IIB cells was similar to that observed in type II cells isolated from untreated rats. These data indicate that hypertrophic type II cells may be isolated from the lungs of silica-treated rats and separated from normal type II cells thus allowing the role of these unusual type II cells in lung injury and repair to be investigated.     

氨溴索对抗低氧性肺动脉高压大鼠慢性肺损伤的保护作用

目的:探讨氨溴索对低氧性肺动脉高压大鼠慢性肺损伤的对抗作用。方法:36只Wistar雄性大鼠,随机分成 3组:正常对照组,低氧组,氨溴索干预组。后 2组大鼠制成低氧性肺动脉高压模型。检测肺动脉平均压及血液和肺匀浆超氧化物歧化酶(SOD)活性及过氧化脂质(LPO)和一氧化氮(NO)的含量,各组随机选取 10只大鼠,取其右下肺叶做病理组织切片,观察肺组织和肺血管损伤的情况。结果:低氧组大鼠血液和肺组织SOD和NO水平明显低于正常对照组,而血浆和肺组织LPO水平明显高于正常对照组(P均 <0.01);氨溴索干预组大鼠血液和肺组织SOD和NO水平明显高于低氧组,而血液和肺组织LPO水平明显低于低氧组(P均 <0.01),氨溴索干预组肺动脉平均压显著低于低氧组(P <0.01);氨溴索干预组的肺动脉平滑肌细胞和细胞外基质的病变明显轻于低氧组,管壁面积占总面积的百分比和管壁厚度占外径的百分比明显低于低氧组(P <0.01)。结论:慢性低氧大鼠体内存在着氧化/抗氧化失衡,可能是肺组织和血管损伤的原因之一;氨溴索具有较好的抗氧化能力,它的应用使内皮细胞的损伤减轻.     

Increased intracellular levels of calcitonin gene-related peptide-like immunoreactivity in pulmonary endocrine cells of hypoxic rats

The mammalian respiratory tract contains innervated groups of endocrine cells which are believed to respond to hypoxia. We have demonstrated the involvement of a specific regulatory peptide produced by the cells, calcitonin gene-related peptide (CGRP), in this response. Cells immunoreactive for CGRP or for protein gene product 9.5 (PGP 9.5), a general marker of nerves and endocrine cells, were quantified in sections of lungs from hypoxic (21 days, 10 per cent O2) and normoxic rats. An immunostaining method employing supra-optimal dilutions of primary antiserum was used. This detects variations in antigen concentration which may be masked if the routine, optimal dilution is used. The number of CGRP-immunoreactive endocrine cells was significantly (P less than 0.001) greater in the lungs of hypoxic rats (76.9 +/- 10.1 cells/cm2, mean +/- SEM) compared with controls (19.7 +/- 2.4). However, the numbers of PGP 9.5-immunoreactive cells were the same in both groups (81.3 +/- 12.2, hypoxic; 79.5 +/- 9.8 control), suggesting that the total number of endocrine cells did not change. It is concluded therefore that the apparent increase in CGRP-immunoreactive endocrine cells in hypoxic rat lungs is due to increased intracellular levels of the peptide. Since CGRP is a vasodilator, this could have important implications in the vasoconstrictor response to hypoxia.     

微囊化兔雪旺细胞移植对大鼠损伤脊髓胶质纤维酸性蛋白表达的影响

目的:观察大鼠脊髓损伤后及进行微囊化兔雪旺细胞移植后胶质纤维酸性蛋白(GFAP)表达的变化.方法: 130只成年SD大鼠随机分为微囊组、细胞悬液组、损伤对照组和正常对照组4组,术后3、 7、 14及28d,冰冻切片行免疫组织化学显色观察GFAP表达的变化.结果:大鼠脊髓损伤后3～14d, GFAP阳性细胞数及平均光密度均增加;至第28天时则减少,但仍高于正常组.其中阳性细胞数和平均光密度在第7天开始,微囊组与细胞悬液组、损伤组比较均有明显降低.结论: 微囊化异种雪旺细胞移植能抑制损伤脊髓GFAP的表达,减轻由反应性胶质化所形成的胶质瘢痕.     

Muscle conduction velocity and morphology after prolonged hypoxemia and diabetes in rats.

One of the electrophysiological abnormalities in the experimental rat model of chronic hypoxia (10% O2) and in the experimental rat model of diabetes is an increase in jitter in the stimulated single fibre EMG, which is thought to result from a primary disorder of the axon with its terminal branches. But muscle fibre alterations that influence the propagation of muscle action potentials can also increase jitter. The contribution of possible changes in muscle conduction velocity and muscle morphology to jitter were investigated in the present study. Muscle conduction velocities were determined and compared with the morphological properties of muscle fibers in muscles of control, chronic hypoxic and terminal-stage diabetic rats. The mean muscle conduction velocities were in the same range in the three groups. The muscle fibre type composition and the mean muscle fibre diameters were about the same in the hypoxic and the control rats, whereas the muscles of the diabetic rats showed a higher percentage of intermediate type muscle fibres, which is suggestive of muscle degeneration, and a smaller mean muscle fibre diameter in comparison with muscles of the hypoxic and the control rats. It is concluded that the similarities between the electrophysiological properties of the muscles despite differences in their morphology, indicate that there is primary axonal degeneration in diabetic hypoxic rats.     

An objective morphologic parameter to aid in the diagnosis of flat urothelial carcinoma in situ

The diagnosis of carcinoma in situ (CIS) lacks objective criteria and is subject to misdiagnosis. We identified 20 bladder biopsy cases each of CIS, urothelial dysplasia, and normal urothelium according to the 1998 World Health Organization/International Society of Urological Pathology consensus classification of urothelial neoplasms. Lymphocytes from 10 bladder biopsy specimens were chosen as reference cells. Using an image analysis system, we measured the following nuclear features: area, diameter, roundness, ellipticity, and optical density (maximum, minimum, mean, median, standard deviation, and quartiles). We measured a mean of 75 urothelial nuclei/case and a total of 500 lymphocytes. Roundness and ellipticity were not useful in distinguishing among the 3 groups. The best discriminators were mean nuclear area and mean nuclear area of the 25% largest nuclei (upper quartile) of urothelial cells compared with lymphocytes. The mean nuclear area relative to lymphocytes was 1.8 times (1.2 to 2.5 times) in normal urothelium, 2.4 times (1.6 to 3.0 times) in urothelial dysplasia, and 3.6 times (2.8 to 5.7 times) in CIS. The mean upper quartile nuclear area relative to lymphocytes was 2.2 times (1.4 to 2.8 times) in normal urothelium (P <.0001), 2.9 times (1.8 to 3.6 times) in urothelial dysplasia (P <.0001), and 4.9 times (4.0 to 7.6 times) in CIS (P <.0001). The difference in optical density was statistically significant between CIS and the other 2 histologic categories (P <.0001). Nuclear area is an easy and objective morphologic parameter for the evaluation of bladder biopsy specimens. Pathologists can assess the size of urothelial nuclei without using an image analysis system and compare them with the size of nuclei of lymphocytes, which are almost always present in a bladder biopsy specimen. Dysplasia, which is a somewhat ambiguous lesion, overlaps in its measurements with those of benign urothelium. The most useful morphologic parameter is the mean nuclear area of the 25% largest nuclei; CIS nuclei are approximately 5 times the size of lymphocytes, whereas normal urothelial nuclei are only 2 times the size of lymphocytes.     

Nuclear morphology of follicular center cell-associated T-cells: an immunoultrastructural study of follicular hyperplasia and follicular center cell lymphomas

Although the immunophenotypic nature and distribution of T-cells in normal follicular centers and in follicular center cell lymphomas have been studied in great detail, the morphology of these cells has been largely ignored. Immunoultrastructural studies using UCHT-1, an antibody to the T-cell receptor-associated CD3 antigen, were therefore performed on four tonsils with reactive follicular hyperplasia and on four follicular center cell lymphomas. T-cells present in normal follicular centers had a mean maximum nuclear diameter of 4.9 +/- 0.93 microns and were not significantly different from those associated with neoplastic follicular center cells which had a maximum nuclear diameter of 4.9 +/- 1.2 microns. In contrast, the T-cells in normal interfollicular T-zones had a mean maximum nuclear diameter of only 4.4 +/- 0.81 microns which was significantly smaller than either of the previous two groups (P = 0.002 and P = 0.004, respectively). Similarly, T-cells in a relatively uninvolved T-zone in a follicular center cell lymphoma had a mean maximum nuclear diameter of 4.5 +/- 0.78 microns. The nuclear configuration of the follicular center cell-associated and interfollicular T-cells ranged from round to clefted with the greatest number of clefted T-cells being associated with the follicular center cell lymphomas. These data demonstrate that T-cells associated with either normal or neoplastic follicular center cells tend to be larger than interfollicular T-cells. Because of the very variable nuclear configurations of these T-cells, not all cells with clefted nuclei in follicular centers or follicular center cell lymphomas can be assumed to be of B-cell origin.     

The effect of passage number on the stimulation by hypoxia of growth and sprouting activity in cultured aortic endothelium from the rat

Primary cultures of endothelium from aortas of rats were harvested at different times to obtain a series of cell lines which had been through a varying number of passages ranging from 3 to 30. These were plated into tissue culture flasks half of which were gassed with 5% CO2 and air to act as controls. The other half were grown in a hypoxic environment employing a gas mixture containing 5.3% O2 and 6% CO2. Cells in their 36th passage were also used to derive growth curves of hypoxic and control cells. The degree of endothelial sprouting of all cultures after 9 days growth was assessed by point counting. At all passage numbers sprouting was more extensive in hypoxic than control cultures but this difference was most significant in early passages. The degree of sprouting stimulated by hypoxia remained constant for passages 3-5 whereas the sprouting activity of equivalent control cultures declined steadily. In late passages the degree of spontaneous sprouting fell sharply to a constant low level, as did that in hypoxic cultures, but not to such a low value. Hypoxia did not induce any marked increase in growth of endothelium in its 36th passage, unlike its previously reported effect on early passages. It is concluded that the stimulatory influence of hypoxia on the growth and sprouting activity of cultured endothelium falls with repeated passage and this decline is probably dependent upon the number of population doublings through which the cells have passed.     

Rat pulmonary circulation after chronic hypoxia: hemodynamic and structural features.

In 55 Sprague-Dawley rats (mean wt, 277 +/- 6.2 g) exposed to hypobaric hypoxia (air at 380 mmHg), and 23 weight-matched controls kept in room air, pulmonary and systemic artery pressures were measured daily for 2 wk via indwelling catheters. After each day of exposure, 1 or 2 hypoxic rats, to a total of 20, and 5 control rats were killed during the experiment. In these rats, the pulmonary arterial tree was injected post mortem with barium-gelatin and inflated with formaldehyde solution, and three structural features were quantified microscopically: 1) abnormal extension of muscle into peripheral arteries where it is not normally present (EMPA); 2) increased wall thickness of the normally muscular arteries, expressed as a percentage of external diameter (%WT); and 3) reduction in artery number expressed as an increase in the ratio of alveoli to arteries (A/a). Mean pulmonary artery pressure (Ppa) rose significantly after day 3 of hypoxic exposure (P less than 0.05) and had doubled by day 14; the mean systemic artery pressure (Psa) of hypoxic rats and Ppa and Psa of control rats were unchanged. The level of Ppa correlated with the degree of structural changes; for EMPA, r = 0.84; for %WT, r = 0.64; and for A/a, r = 0.73 (P less than 0.001 in all.     

Intact and sympathectomized carotid bodies of long-term hypoxic rats: a morphometric ultrastructural study

Summary The ultrastructure of the carotid body after exposure to hypoxia (10% O₂) for one, two or three weeks was investigated morphometrically. The study was performed on rats after unilateral removal of the superior cervical ganglion. The normally occurring bimodal distribution of type I cells, representing cells with small vesicle profile diameters (SVC) and large vesicle profile diameters (LVC) respectively, changed after one week of hypoxia into a unimodal population. After one or two weeks of hypoxia the diameter range of dense-cored vesicle (DCV) profiles in type I cells was not different from that of DCV profiles in control LVC. After three weeks of hypoxia the DCV vesicle size was intermediate between those of control SVC and LVC. The volume density of DCV decreased after one week but returned to initial values after two and three weeks of hypoxia. At two or three weeks of hypoxia, however, the total cell volume was increased about 1.4 times which should reflect an increase of the total content of DCV at these times of exposure to hypoxia. An increased mean area of cell profiles indicates a hypertrophy of the type I cells, but no signs of hyperplasia could be detected. The ganglionectomy did not cause any remarkable changes compared to the intact carotid body except for a higher volume density of DCV during the early periods of hypoxia.It is inferred from the study that the increased total mass of type I cell tissue during long-term hypoxia is due to a hypertrophy of the cells. Furthermore, the type I cells can increase their storage capacity for catecholamines during hypoxia by an increase in the size and number of DCV.     

Expression of adhesion molecules in chronic serum sickness in rats

Peripheral blood leukocytes infiltrate the kidney in chronic serum sickness (CSS). We therefore studied the expression of CD54 and its ligands CD18 and CD11b/c in CSS in 10 rats with CSS, 6 rats immunized similarly who did not developed proteinuria (no-CSS group), and 10 normal rats (control group). Intense (6 to 35 times more than controls) leukocyte infiltration was observed in CSS. The CSS group over-expressed CD54 in glomeruli and interstitium in association with increments in CD18- and CD11b/c-positive cells ranging 2.5 to 7 times the number found in controls. 75% of infiltrating leukocytes expressed CD18 and 87% expressed CD11b/c. The non-CSS group had leukocyte infiltration and expression of adhesion molecules similar to control group. Adherence of CD43-positive cells to renal tissues was 4 times higher in renal tissue from CSS rats than to normal kidney. Pretreatment with corresponding Mabs reduced adherence by half. We concluded that over-expression of CD54 and its ligands CD18 and CD11b/c in infiltrating leukocytes occur in CSS. Binding experiments suggest the functional relevance of these molecules.     

肾上腺髓质素缓解大鼠低氧性肺动脉高压

目的探讨肾上腺髓质素(ADM)对大鼠低氧性肺动脉高压的防治作用及机制。方法雄性Wistar大鼠18只,分为对照组、低氧组和低氧 ADM组,每组6只。持续皮下注射ADM1-50后,测定平均肺动脉压(mPAP)、右心室肥大指数RV/(LV S)、肺小动脉病理及形态计量学和体循环平均压(mSBP),放免法测定肺动脉血浆ADM水平,原位杂交测定肺动脉ADMR mRNA的表达。结果①低氧组大鼠mPAP,RV/(LV S),管壁厚度与血管外径比值(MT%)及管壁面积与血管面积比值(MA%)均显著升高(P<0.01);ADM组显著缓解以上变化(P<0.01)。②低氧组与低氧 ADM组肺动脉血浆ADM浓度均高于对照组,且低氧 ADM组较低氧组ADM浓度低(P<0.05)。③低氧组与低氧 ADM组的ADMR mRNA表达较对照组增强(P<0.01)。结论持续皮下注射ADM对慢性低氧所致的肺动脉高压及肺血管重塑有预防和部分逆转作用。     

慢性低氧性肺动脉高压大鼠肺组织P53表达增高

目的观察P53在低氧性肺动脉高压大鼠肺组织中的表达。方法采用减压低氧方法复制大鼠慢性低氧性肺动脉高压模型;取肺组织,常规SABC免疫组化法染色和Hoechst染色,观察P53表达的变化及细胞凋亡变化。结果P53在慢性肺动脉高压大鼠肺小动脉壁中有少量表达,其中低氧3周组>低氧2周组>正常组。Hoechst染色显示肺组织凋亡细胞增加,其变化趋势与P53的表达变化趋势相同。结论在慢性低氧性肺动脉高压形成过程中,肺小动脉壁发生了增殖和凋亡,程度随低氧时间的延长而增加,同时P53表达增多,提示P53参与了慢性低氧性肺动脉高压肺小血管重建的调控。     

Methods for decreasing the statistical variance of stereological estimates

Three methods are described for decreasing the statistical variance of stereological estimates. Method 1 uses profile boundaries and surface densities of nuclear membranes, measured in thin sections, to estimate the mean diameter, surface area, and numerical density of spherical and nonspherical nuclei. For the guinea pig pancreas (number(m) = 4), the standard deviations (s.d.) as a percent of the mean for the estimates of the diameters of the exocrine, duct, and endothelial cell nuclei were 1.5%, 3.3% and 1.4%. The estimate for the mean diameter of exocrine nuclei (6.4 +/- 0.1 micron) was based on a spherical model, whereas the estimates for the diameters of the nonspherical (and nonconvex) nuclei of the duct (6.4 +/- 0.2 micron) and endothelial (6.7 +/- 0.1 micron) cells were calculated from the numerical density of the exocrine cells and the relative frequencies of the three cell types (determined from serial reconstructions). In an average cubic centimeter, there were 6.17 X 10(8) +/- 0.32 X 10(8) (s.d. 5.1% of mean) exocrine cells, 1.64 X 10(8) +/- 0.18 X 10(8) (10.9%) duct cells, and 0.803 X 10(8) +/- 0.13 X 10(8) (16.6%) endothelial cells. In contrast to method 1, conventional stereological approaches were found to have standard deviations two- to eightfold larger. Method 2 uses a mean nuclear surface area and a ratio of surface densities to estimate the surface area of a membrane compartment in an average cell. A s.d. equal to 6.5% of the mean was found for the surface area of the outer mitochondrial membrane in an average exocrine cell (672 +/- 43.6 micron 2), which represented an almost fourfold reduction in the s.d. compared with an earlier estimate (Bolender, 1974). Method 3 relates the surface area of a membrane compartment to a standard number of cells. Referenced to 10(6) cells, for example, the surface area of the inner nuclear membrane of endothelial cells had a s.d. equal to 2.9% of the mean, whereas the surface density of the same membrane compartment-referenced to a cm3 of cells-had a s.d. at 19.1% of the mean. In this case, method 3 produced almost a sevenfold reduction in the standard deviation. Similar results were found for exocrine and duct cells. The results of the study indicate that the standard deviation of a stereological estimate can be reduced to a minimum by using a mean nuclear profile boundary to generate an estimate for a nuclear numerical density, which, in turn, can be combined with a surface density to obtain average cell information.