[Analysis of changes in intrinsic neural timescales in male smoking addicts based on whole brain resting-state functional magnetic resonance imaging].

Objective: To investigate the abnormal changes of intrinsic neural time scale (INT) in male smoking addicts based on whole brain resting state functional magnetic resonance imaging (rs-fMRI). Methods: A case-control study. The clinical data and whole brain rs-fMRI data of 139 male subjects, aged (34.1±8.8) years, recruited through the online platform from January 2019 to December 2021 were retrospectively analyzed. According to the existence of smoking addiction, they were divided into smoking addiction group (n=83) and healthy control group (n=56).INT was calculated to reflect the brain neural activity dynamics. Single sample t test was used to obtain the whole brain spatial distribution maps of INT in smoking addiction group and the control group. Then two-sample t test was conducted to explore the difference of INT between the smoking addition group and the healthy control group, with age and years of education as covariates. Finally, Spearman correlation analysis was used to explore the relationship between INT and nicotine dependence scale score and smoking index. Results: Subjects with smoking addiction and healthy control group showed a similar pattern of hierarchical neural timescales, namely shorter INT in sensorimotor areas and longer INT in parietal lobe, posterior cingulate cortex. In addition, in the smoking addiction group, the left medial occipital gyrus (peak t=-3.18), left suproccipital gyrus (peak t=-3.66), bilateral pericalar cleft cortex (left: peak t=-3.02, right: peak t=-3.22), bilateral lingual gyrus (left: peak t=-3.10, right: t peak=-3.04), left cuneus (peak t=-2.97), default network associated brain region [left anterior cuneus(peak t=-3.23), left angular gyrus (peak t=-3.07), and left posterior cingulate cortex (peak t=-3.54) were significantly lower than those of healthy controls (gaussian random field correction, voxel level all P<0.005, mass level all P<0.05). However, there was no significant correlation between INT and nicotine dependence scale score and smoking index (both P>0.05 after Bonferroni correction). Conclusion: Compared with healthy controls, smoking addicts showed abnormal changes in the dynamics of neural activity in the visual cortex and the default network.

[Primary synovial sarcoma of lung: a clinicopathological analysis of 12 cases].

Objective: To investigate the clinicopathological features, immunophenotype, molecular features and differential diagnosis of primary synovial sarcoma of the lung (PSSL). Methods: Twelve cases of PSSL were collected at Henan Provincial People's Hospital, during May 2010 and April 2021, and their clinicopathological parameters were summarized. SS18-SSX, H3K27Me3, and SOX2 were added to the original immunomarkers to evaluate their diagnostic value for PSSL. Results: The age of 12 patients when diagnosed ranged from 32 to 75 years (mean of 50 years). There were 7 males and 5 females, 2 left lung cases and 10 right lung cases. Of the 6 patients who underwent surgical resection, five cases were confined to lung tissue (T1), one case had mediastinal invasion (T3), two cases had regional lymph node metastasis (N1), and none had distal metastasis. Microscopically, 11 cases showed monophasic spindle cell type and one case showed biphasic type composed of mainly epithelial cells consisting of cuboidal to columnar cells with glandular and cribriform structures. It was difficult to make the diagnosis by using the biopsy specimens. Immunohistochemistry (IHC) showed CKpan expression in 8 of 12 cases; EMA expression in 11 of 12 case; TLE1 expression in 8 of 12 cases; S-100 protein expression in two of 12 cases; various expression of bcl-2 and vimentin in 12 cases, but no expression of SOX10 and CD34 in all the cases. The Ki-67 index was 15%-30%. The expression of SS18-SSX fusion antibody was diffusely and strongly positive in all 12 cases. SOX2 was partially or diffusely expressed in 8 of 12 cases, with strong expression in the epithelial component. H3K27Me3 was absent in 3 of 12 cases. SS18 gene translocation was confirmed by fluorescence in situ hybridization (FISH) test in all 12 samples. Six cases underwent surgery and postoperative chemotherapy, while the other six cases had chemotherapy alone. Ten patients were followed up after 9-114 months, with an average of 41 months and a median of 26 months. Five patients survived and five died of the disease within two years. Conclusions: PSSL is rare and has a broad morphological spectrum. IHC and molecular tests are needed for definitive diagnosis. Compared with current commonly used IHC markers, SS18-SSX fusion antibody has better sensitivity to PSSL, which could be used as an alternative for FISH, reverse transcription-polymerase chain reaction or next generation sequencing in the diagnosis of PSSL.

[Prognostic value of combined preoperative fibrinogen and platelet-lymphocyte ratio in patients with early recurrent hepatocellular carcinoma].

Objective: To explore the risk factors in HBV-associated hepatocellular carcinoma (HCC) patients with early recurrence after ablation and to establish predictive model. Methods: A total of 81 patients with HBV-related HCC who underwent ablation from January 2016 to December 2016 were included in Beijing Youan Hospital, including 66 males and 15 females. Standard medical records were collected, which were summarized as follows: demographic data, liver function, the number and size of tumors and the modality of ablation. Univariate and multivariate analysis were performed to identify the independent risk factors.The ROC curve was used to determine prognostic value. Cox proportional hazards model was used to establish predictive model, and the scores of risk factors were assigned according to HR value. Patients were divided into high-risk group and low-risk group in accordance with scores.The analysis of early recurrence rate was performed by the Kaplan-Meier method. Results: Tumor number, fibrinogen (Fib) and platelet-lymphocyte rate (PLR) were independently correlated with recurrence-free survival (RFS). The AUCs of Fib, PLR and Fib-PLR were 72.9%, 71.5% and 81.8%. The recurrence rates of the low-risk group were 4.9%,7.3% and 29.3% at 6 months,12 months and 24 months while 14.6%,43.9% and 78.1% in high-risk group. Two groups revealed statistically significant differences (all P<0.05). Conclusion: Tumor number, Fib, and PLR may be used as a set of predictive indicator of early recurrence in HBV-associated HCC patients after ablation.

[Development of a quantitative serum assay of Golgi protein 73 in hepatocellular carcinoma using xMAP technology].

Objective: To establish a quantitative assay of serum Golgi protein 73 (GP73) using xMAP technology and evaluate its performance. Methods: Monoclonal antibodies against GP73 were prepared and purified, and antibody pair screening was performed by double-antibody sandwich enzyme-linked immunosorbent assay. The screened antibodies were used to construct a Luminex liquid chip detection system, and the analysis performance of the detection system was evaluated. The serum levels of GP73 were detected in 90 clinical samples from healthy controls and patients with chronic hepatitis B infection (CHB) and hepatocellular carcinoma (HCC). Results: Five anti-GP73 monoclonal antibodies were prepared and purified, and 5 antibody pairs were successfully screened. The Luminex liquid chip detection system of GP73 was successfully constructed using 8F10D1 and 10B9F11 antibody pairs. The analytical performance evaluation showed that the sensitivity of this system was 0.25 ng/ml and the dynamic range was 0.25-100 ng/ml. No cross reactivity was observed. The intra- and inter-assay variation for GP73 was <8% and <11%, respectively. The recovery was 83%-92%. The linear regression equation was y=1.141x+ 6.436 (r(2)=0.998 4, P<0.001). The GP73 concentrations in the serum samples of healthy control, CHB group, and HCC group were 42.8 (38.68, 55.90) ng/ml, 61.49 (43.59, 81) ng/ml, and 122.78 (49.36 liter, 264.55) ng/ml, respectively. The levels of GP73 in HCC group were significantly higher than those in CHB group and healthy controls (P<0.05). Moreover, the levels of GP73 in CHB group were significantly higher than those in healthy controls (P<0.05). Conclusions: A liquid chip detection system of GP73 was successfully constructed. It provides a powerful tool for the clinical application of GP73 in the future.

Combination of the gamma-glutamyltransferase-to-prealbumin ratio and other indicators may be a novel marker for predicting the prognosis of patients with hepatocellular carcinoma undergoing locoregional ablative therapies.

OBJECTIVE: The aim of this study was to investigate the prognostic significance of the serum γ-glutamyltransferase (γ-GT)-to-prealbumin ratio (GPR) and whether combining this ratio with other parameters can lead to an improved prognostic value for patients with hepatocellular carcinoma (HCC) undergoing transcatheter arterial chemoembolization (TACE) combined with local ablation therapy. METHODS: A total of 235 HCC patients who were treated with combined therapies were retrospectively analyzed. The demographic data and clinicopathological data were collected. A fibrinogen (Fib)-GPR score of 2 was assigned to patients with elevated Fib and GPR values, and a score of 1 or 0 was assigned to patients with one or neither of these two markers, respectively. In addition, an N-score of 2 was assigned to patients with low neutrophil and high GPR values, and a score of 1 or 0 was assigned to patients with one or neither of these two markers, respectively. The optimal cutoff values and prognostic roles of GPR and other markers were identified according to the time-dependent receiver operating characteristic (ROC) curves and Youden's index. RESULTS: Multiple tumors, high levels of α-fetoprotein (AFP) and Fib, as well as a high GPR, were found to be independent risk factors in recurrent patients, while multiple tumors, a low neutrophil count, and a high GPR were associated with reduced overall survival (OS) in patients with HCC who received combined therapies. Patients with a Fib-GPR score of 2 and N-GPR score of 2 had poor recurrence-free survival (RFS) and OS, respectively. CONCLUSIONS: Fib-GPR and N-GPR scores may be helpful in predicting both recurrence and the prognosis of HCC patients, thereby assisting in the process to make a true clinical decision and optimize therapeutic options.

[Analysis of the entrance and suture method of umbilical incision in gynecological laparoscopy].

Objective: To explore the entrance and suture method of umbilical incision in gynecological laparoscopy. Methods: A total of 204 cases of gynecologic laparoscopy in our hospital from 2013 to 2016 were reviewed respectively. All the cases used two kinds of approach of umbilical incision: intra-umbilical incision and peri-umbilical incision (longitudinal/transverse oblique/arc incision according to the bellybutton natural skin folds) and two methods of suture: the suture of "U" and the suture of the whole subcutaneous tissue. Two groups were randomly assigned based on the entrance and suture method with each group 102 cases. The peri-operative outcomes were compared, including intra-operative and postoperative bleeding, postoperative incision fat liquefaction and infection, incision pain, incision appearance satisfaction and incision healing satisfaction. Results: The difference was statistically significant in the intra-operative and postoperative bleeding between two groups of intra-umbilical incision and peri-umbilical incision (P<0.05). There was statistically significant difference in postoperative incision fat liquefaction, infection and incision pain between two groups of the suture of "U" and the suture of the whole subcutaneous tissue (P<0.05). The incision appearance satisfaction showed no difference (P>0.05), but the difference was statistically significant (P<0.05) in the incision healing satisfaction between two groups. Conclusion: The peri-umbilical incision (longitudinal/transverse oblique/arc incision according to the bellybutton natural skin folds) and suture of the whole subcutaneous tissue can be the feasible modified methods with high practicability and security, good cosmetic result. It should be promoted in gynecologic laparoscopy.

[The expressions and the roles of SDF-1/CXCR-4 and SDF-1/CXCR-4 in human endometriosis].

Objective: To investigate the expressions and significances of SDF-1 and its receptor CXCR-4 in endometriosis. Methods: 50 hysteromyoma patients treated at Beijing Tongren Hospital, Capital Medical University between 1(st) January 2016 and 31(st) December 2017 were divided into control group, that is, non-endometriosis group, while another 50 endometriosis patients were divided into experimental group.The endometrial tissues, endometriosis lesions, and peritoneal fluid samples of hysteromyoma patients were collected by operation.RT-PCR, ELISA and immunohistochemistry were adopted to detect the expressions of SDF-1 and CXCR-4 in the two groups.Cell count was used to analyze the roles of SDF-1 and CXCR4 in the mitosis and proliferation of endometrial stromal cells. Results: The mean value of SDF-1 and CXCR-4 expressions in ascites or peritoneal fluid of endometriosis patients were (2.56±0.33) mg/L and (4.47±0.32) mg/L, respectively. The mean concentrations in ascites or peritoneal fluid in hysteromyoma patients were (1.39±0.36) mg/L and (3.16±0.32) mg/L, respectively.The expressions of SDF-1 and CXCR-4 in ascites or peritoneal fluid of endometriosis patients were both significantly higher than those of patients in non-endometriosis group (P<0.05). SDF-1 and CXCR-4 were expressed in both endometriosis lesions and the glandular epithelial cells and mesenchymal cells of normal endometrial tissue.Positive staining sites were located in the cytoplasm.A value was used to calculate and analyze the expression of immune staining.The mean A value of SDF-1 and CXCR-4 in endometriosis group were 0.21±0.13 and 0.21±0.13, respectively, and the mean A value in normal endometrial tissues were 0.15±0.13 and 0.14±0.13, respectively.The expressions of these two in endometrial tissues were significantly higher than that in normal endometrial tissues, and the differences were statistically significant (P<0.05). The expression of CXCR-4 mRNA was abundant in the mesenchymal cells of endometriosis cultured in vitro.SDF-1 promoted the mitosis and proliferation of endometrial stromal cells cultured in vitro in a dose-dependent manner.The neutralizing antibody against CXCR-4 was obviously inhibited. Conclusion: The high expressions of SDF-1 and CXCR-4 in endometriosis as well as SDF-1 through its specific receptor CXCR-4 promoted the mitosis and proliferation of endometrial stromal cells, suggesting that SDF-1 and CXCR-4 played important roles in the pathogenesis of endometriosis.

[The social marketing models and policy advices for HIV rapid testing initiated by non-govermental organization].

Currently, a growing number of community-based organizations are providing rapid HIV testing service in various forms, some people with specific needs also purchase HIV rapid test papers through online sales channels, those imply that the demand of HIV self-test is in increasing year by year.In this paper, aims to understand the current situation of HIV rapid test led by CBOs and the approach, strategies and results of social marketing by means of expert interviews and site visits. Hope to illustrate the current situation, and make recommendations for future work.

Mechanism of action of ethylene sulfite and vinylene carbonate electrolyte additives in LiNi1/3Mn1/3Co1/3O2/graphite pouch cells: electrochemical, GC-MS and XPS analysis.

The role of ethylene sulfite used either alone or in combination with VC in LiNi1/3Mn1/3Co1/3O2 (NMC)/graphite pouch cells was studied by correlating data from differential capacity (dQ/dV) analysis, gas chromatography/mass spectroscopy (GC-MS), theoretical calculations, ultrahigh precision coulometry, storage experiments and X-ray photoelectron spectroscopy. For cells containing VC alone, the electrochemical performance and gas production were greatly improved, compared to cells without VC, due to the formation of more stable and protective SEI films at both electrode surfaces by a polymer of VC. For cells with ES alone, a vigorous reactivity was observed due to preferential reduction that also generated large amounts of gas during formation. The dramatic decrease in electrochemical performance as well as the continuous production of gas during cycling in cells with ES was explained by the formation of a very thin and ineffective SEI film at the NMC surface. The suppression of the vigorous reaction of ES in cells with both ES and VC occurred because the solvation energy of Li(+) by VC is smaller than that of EC so VC is reduced first during formation. During charge-discharge cycling, a slow consumption of ES occurred and different sulfur species were observed on the electrodes when VC was combined with ES. SEI film formation processes and SEI composition were therefore dominated by VC and the electrochemical performance of cells with both VC and ES were similar compared to those of cells with VC alone.

Cardiovascular risk profiles in relation to newly diagnosed type 2 diabetes diagnosed by either glucose or HbA1c criteria in Chinese adults in Qingdao, China.

AIMS: To study the cardiovascular disease risk profiles in newly diagnosed diabetes diagnosed by either glucose or/and HbA(1c) criteria in Chinese adults. METHODS: Two population-based cross-sectional studies were conducted in 2006 and 2009, respectively. Data from 1987 men and 2815 women aged 35-74 years were analysed. Newly diagnosed diabetes was defined according to either glucose (fasting and/or 2-h glucose), HbA(1c) or both criteria. RESULTS: Ageing, positive family history of diabetes, elevated levels of waist circumference, systolic blood pressure, total cholesterol, triglycerides and γ-glutamyl transferase were independently associated with newly diagnosed diabetes defined by glucose criterion alone, but not for diabetes defined by HbA(1c) criterion alone. Only waist circumference, total cholesterol and smoking were significantly associated with the presence of diabetes defined by HbA(1c) criterion alone. CONCLUSIONS: Cardiovascular disease risk profiles were different in patients with newly diagnosed diabetes defined by the two diagnostic criteria for diabetes. This may have certain clinical implications on diabetes management and research.

Respiratory variation of mitral and pulmonary venous Doppler flow velocities in constrictive pericarditis before and after pericardiectomy.

The objective of this study was to determine whether Doppler echocardiography is useful in assessing the effects of pericardiectomy in patients with constrictive pericarditis by studying the postoperative change in the respiratory variation of mitral inflow and pulmonary venous Doppler flows. The study population consisted of 35 cases with surgically proven constrictive pericarditis. Thirty-five patients had preoperative Doppler echocardiography, whereas 4 patients died of non-cardiac causes and 1 patient had a heart transplant before follow-up. Postoperative studies were performed at a mean of 1081 +/- 84 days (range 120-2700 days) after pericardiectomy. The mean (+/- SD) respiratory variation changed after surgery from a baseline value of 17% +/- 14% to 8% +/- 8% for peak mitral E velocity (P <.01); from 25% +/- 18% to 7% +/- 13% (P <.001) for pulmonary venous (PV) peak diastolic flow velocity, and from 21% +/- 13% to 11% +/- 13% (P =.009) for PV peak systolic flow velocity. The 23 patients who became asymptomatic after surgery had a significantly lower mean mitral and PV respiratory variation than the 7 patients who were NYHA class II (4% +/- 4% and 6% +/- 4% vs 21% +/- 6% and 19% +/- 10%, respectively, P <.0001 for both). Pulsed Doppler echocardiographic assessment of respiratory variation is useful for evaluating the outcome of pericardiectomy.

Clinical and echocardiographic characteristics of papillary fibroelastomas: a retrospective and prospective study in 162 patients.

BACKGROUND: Cardiac papillary fibroelastoma (CPF) is a primary cardiac neoplasm that is increasingly detected by echocardiography. The clinical manifestations of this entity are not well described. METHODS AND RESULTS: In a 16-year period, we identified patients with CPF from our pathology and echocardiography databases. A total of 162 patients had pathologically confirmed CPF. Echocardiography was performed in 141 patients with 158 CPFs, and 48 patients had CPFs that were not visible by echocardiography (<0.2 cm), leaving an echocardiographic subgroup of 93 patients with 110 CPFs. An additional 45 patients with a presumed diagnosis of CPF were identified. The mean age of the patients was 60+/-16 years of age, and 46.1% were male. Echocardiographically, the mean size of the CPFs was 9+/-4.6 mm; 82.7% occurred on valves (aortic more than mitral), 43.6% were mobile, and 91.4% were single. During a follow-up period of 11+/-22 months, 23 of 26 patients with a prospective diagnosis of CPF that was confirmed by pathological examination had symptoms that could be attributable to embolization. In the group of 45 patients with a presumed diagnosis of CPF, 3 patients had symptoms that were likely due to embolization (incidence, 6.6%) during a follow-up period of 552+/-706 days. CONCLUSIONS: CPFs are generally small and single, occur most often on valvular surfaces, and may be mobile, resulting in embolization. Because of the potential for embolic events, symptomatic patients, patients undergoing cardiac surgery for other lesions, and those with highly mobile and large CPFs should be considered for surgical excision.

Cigarette smoke exposure causes constriction of rat lung.

Cigarette smoke is known to cause acute increases in airway resistance, but the mechanisms behind this effect are unknown. Lung explants were utilized to examine the constrictive effects of acute cigarette smoke exposure on bronchioles from rats in vitro that had or had not been previously exposed to cigarette smoke in vivo. It was found that smoke induced a small but consistent degree of contraction of the airways in vitro, which could be reduced by an endothelin receptor antagonist in the animals which had had no previous smoke exposure in vivo, and reduced by the oxidant scavengers superoxide dismutase or catalase in the animals with previous smoke exposure. In conclusion, cigarette smoke induces acute small airways constriction through both endothelin release and direct oxidant effects; which mechanisms are operative depends on the prior smoking status.

Dissociation of chronic vascular cell proliferation and vascular contractility after chronic cigarette smoke exposure.

In guinea pigs, chronic cigarette smoke exposure produces physiological and structural alterations in the pulmonary vasculature via unknown mechanisms. This study aimed to determine whether chronic cigarette smoke exposure can induce altered pulmonary vascular reactivity, and whether chronic smoke exposure would be associated with a continued increase in vascular cell deoxyribonucleic acid (DNA) synthesis, indicative of cell proliferation. Guinea-pigs were therefore exposed to two regimens of smoke. In the first experiment, animals were exposed once to the smoke of seven cigarettes, and sacrificed 24 h post-smoke, while in the second experiment, the guinea-pigs were exposed for 5 days each week for 4 months. Control animals were exposed to air. Lung explant preparations and computer linked image photography were utilized to determine vascular reactivity, and DNA synthesis was assessed using the 5-bromo-2'-deoxyuridine technique. Neither acute nor chronic smoke exposure affected vascular reactivity, although the older animals had lesser reactivity. In the chronically smoked animals, evidence was found of ongoing vascular DNA synthesis, and evidence of structural alterations with increased muscularization of the arterioles (34.7+/-7.6% of arterioles in control versus 62.7+/-5.5% after smoke exposure). Despite evidence of continued deoxyribonucleic acid synthesis in the peribronchiolar vessels, the alterations of vascular physiology previously found in this model cannot be ascribed to increased reactivity at this site. Instead, the chronic deoxyribonucleic acid synthesis in the arterioles adjacent to the alveolar ducts, culminating in an increased number of fully muscularized vessels, would suggest this compartment as the most probable source.

Inferior vena caval masses identified by echocardiography.

The most common cause of an inferior vena caval mass is renal cell carcinoma that extends through the lumen, occurring in 47 of 62 patients (85%). Detection of an inferior vena caval mass affects the surgical approach requiring cardiopulmonary bypass for resection when the mass extends to the heart.

Long term cigarette smoke exposure does not increase airway responsiveness in rats.

To ascertain whether chronic cigarette smoke exposure induces increased airway responsiveness, we performed methacholine response tests in Sprague-Dawley rats by calculating pulmonary resistance after nebulization of saline followed by an increasing concentration of methacholine. We also calculated the concentration of methacholine which doubled the baseline resistance (R200). Tests were performed at baseline and after 2, 4, 8, and 12 months of exposure to the smoke of seven cigarettes per day, 5 days each week; control animals were exposed to room air. At the completion of the study, there were 13 rats in the smoke-exposed group and 7 rats remaining in the control group. Airway morphology was assessed using a point counting technique. We found that (1) chronic exposure to cigarette smoke did not alter either the baseline resistance or the R200; (2) the saline baseline resistance decreased over time in the control animals; and (3) at the 12-month time point, smokers with increased baseline airway resistance had greater amounts of airway smooth muscle compared with the smoke-exposed animals without increased resistance. We conclude that in this animal model, long term exposure to cigarette smoke did not alter the response to methacholine but did increase airway smooth muscle and baseline resistance in some but not all animals.

Guinea pig pulmonary hypertension caused by cigarette smoke cannot be explained by capillary bed destruction.

Chronic exposure to cigarette smoke is known to produce pulmonary hypertension in humans and in animal models, but the etiology of this process is controversial. To evaluate whether alterations in the structure of the pulmonary capillary bed or the peribronchiolar arterioles could be correlated with the pulmonary arterial pressure (Ppa), we examined the pulmonary vasculature in guinea pigs that had developed pulmonary hypertension after being exposed to cigarette smoke for 6 mo. The smoke-exposed animals had a significant increased Ppa compared with the control (air-exposed) animals (14.4 +/- 2.4 vs. 9.9 +/- 0.9 cmH2O). In the smoke-exposed animals, there was an increased percentage of muscularized peribronchiolar arterioles (33.5 +/- 5.8% smoke exposed vs. 56.1 +/- 5.8% control), and the capillary diameter and density were significantly decreased in both the center and periphery of the lobule (center diameter 8.8 +/- 1.9, periphery diameter 10.0 +/- 2.0 microns, center density 79 +/- 5, and periphery density 84 +/- 4 in smoked exposed vs. center diameter 7.7 +/- 1.9, periphery diameter 8.6 +/- 2.0 microns, center density 73 +/- 6, and periphery density 77 +/- 6 in controls). Neither group showed any correlation between these values and the Ppa. We conclude that although chronic exposure to cigarette smoke produces alteration of the capillary bed and pulmonary arterioles secondary to emphysematous air-space enlargement, these structural findings cannot explain the increase in Ppa. It appears that pulmonary hypertension due to chronic cigarette smoke exposure is a result of a primary alteration of capillary or muscular arteriolar vascular structure but instead may be secondary to alterations of the dynamic properties of the vascular bed with subsequent increase in vascular resistance.

A longitudinal analysis of pulmonary function in rats during a 12 month cigarette smoke exposure.

We wanted to examine the longitudinal effects of chronic cigarette smoke exposure, and to determine whether the chronic alterations in pulmonary function induced by long-term cigarette smoke exposure in an animal model could be predicted by initial or early alterations in function. A group of Sprague Dawley rats was exposed to the smoke of 7 cigarettes x day(-1) for 5 days x week(-1) during a total period of 12 months. Lung volume, flow-volume curves and pressure-volume curves were recorded at baseline, and after 2, 4, 8 and 12 months of smoke exposure. A control group of rats was subjected to the same regimen of testing, but was not exposed to smoke. Thirteen rats completed the study in the smoke-exposed group and seven rats in the control group. We found that chronic exposure to cigarette smoke produced early abnormalities in pulmonary function, with the forced expiratory volume in one second/forced vital capacity (FEV1/FVC) ratio showing an acceleration of ageing effect, particularly between 4 and 8 months of exposure. In this model, although the two groups had significantly different airflow after 12 months, the initial values in each group were remarkably similar, and we could not identify any pulmonary function test which had predictive value. We conclude that longitudinal studies of cigarette smoke exposure in this rat model allow better characterization of the nature and time course of the effects of smoking on the lung.

Cigarette smoke-induced emphysema in guinea pigs is associated with diffusely decreased capillary density and capillary narrowing.

There is little information about whether alveolar capillaries are altered in emphysema. To examine this question, we used scanning electron microscopic morphometry of microvascular corrosion casts to evaluate capillary structure in a guinea pig model of cigarette smoke-induced emphysema. After 6 months, the mean airspace size in the smoke-exposed animals was 157 +/- 31 microns and 106 +/- 11 microns (p < 0.001) in the control (air-exposed) animals. Because previous results from our laboratory had shown differences in size and density between central and peripheral capillaries in normal guinea pigs, these two areas were sampled separately in the present study. Capillaries in the emphysematous animals were narrowed compared with those in the control animals in both the center (mean diameter, 7.51 +/- 1.95 versus 8.93 +/- 2.01 microns, p < 0.001) and periphery (mean diameter, 8.52 +/- 2.13 versus 10.15 +/- 2.16 microns, p < 0.001) of the lobule. Smoke-exposed animals had a decreased capillary density in both the center (0.73 +/- 0.06 versus 0.79 +/- 0.05, p < 0.001) and periphery (0.77 +/- 0.07 versus 0.84 +/- 0.04, p < 0.001) of the lobule. We conclude that cigarette smoke-induced emphysema is associated with a diffuse and relatively uniform narrowing of capillaries with loss of capillary density throughout the lung. These findings may reflect diffuse smoke-induced abnormalities in the alveolar wall matrix with stretching of capillaries over enlarged airspaces and may partially explain the alteration of ventilation perfusion distribution in cigarette smoke-induced emphysema.

Pulmonary capillaries are smaller in the centre than in the periphery of the guinea-pig lung lobule: possible contributory mechanism for the centrilobular location of emphysema?

We used scanning electron microscopic morphometry of microvascular corrosion casts to compare the capillary structure in the centre and periphery of the lung lobule in the guinea-pig. Capillaries in the centre of the lobule had a lesser diameter than in the periphery (8.6 +/- 1.6 vs 10.4 +/- 1.9 microns respectively, P < 0.001). The polygonal capillary rings differed in structure between the centre and periphery of the lobule, although the number of branches remained constant. Capillary density in the centre of the lung (0.71 +/- 0.05) was significantly less than in its periphery (0.78 +/- 0.06, P < 0.001). We conclude that the capillary structure of the centre of the lung lobule is markedly different from that seen in the periphery. The smaller capillary diameter seen in the centre might be important in trapping polymorphonuclear leucocytes that lose the ability to deform after contact with cigarette smoke components; such an effect could explain why cigarette smoke induced emphysema tends to involve the centre of the lung lobule.