[Prospective study on the effects of resistance training with elastic band at home on muscle function and walking ability of severely burned children]

Objective: To explore the effects of resistance training with elastic band at home on muscle function and walking ability of severely burned children. Methods: A prospective non-randomized controlled study was conducted. From January 2022 to April 2023, 40 children with severe burns who met the inclusion criteria were admitted to Tongren Hospital of Wuhan University & Wuhan Third Hospital. According to the willingness of the children or their families, the children were assigned to conventional rehabilitation group and combined rehabilitation group. During the study, 8 children dropped out of the study, 17 children were finally included in the conventional rehabilitation group with 6 males and 11 females, aged (8.5±2.4) years, and 15 children were included in the combined rehabilitation group with 5 males and 10 females, aged (9.6±2.5) years. The children in the 2 groups received conventional burn rehabilitation treatment in the hospital, including active and passive activity training, scar massage, and pressure therapy. The children in combined rehabilitation group received resistance training with elastic band of 3 to 5 times per week after discharge, and the children in conventional rehabilitation group received daily activity ability training after discharge. Before home rehabilitation training (1 week before discharge) and 12 weeks after home rehabilitation training, the grip strength was measured using a handheld grip dynamometer, the muscle strengths of the upper and lower limbs were measured using a portable dynamometer for muscle strength, lean body mass was measured by bioelectrical impedance measuring instrument, and the 6-min walking distance was measured. Data were statistically analyzed with independent sample t test, paired sample t test, Mann-Whitney U test, or Fisher's exact probability test. Results: After 12 weeks of home rehabilitation training, the grip strengths of children in combined rehabilitation group and conventional rehabilitation group were (15±4) and (11±4) kg, respectively, which were significantly higher than (10±4) and (9±4) kg before home rehabilitation training (with t values of -9.99 and -11.89, respectively, P values all <0.05); the grip strength of children in combined rehabilitation group was significantly higher than that in conventional rehabilitation group (t=3.24, P<0.05). After 12 weeks of home rehabilitation training, the muscle strengths of upper and lower limbs of children in combined rehabilitation group (with t values of -11.39 and -3.40, respectively, P<0.05) and the muscle strengths of upper and lower limbs of children in conventional rehabilitation group (with t values of -7.59 and -6.69, respectively, P<0.05) were significantly higher than those before home rehabilitation training, and the muscle strengths of upper and lower limbs of children in combined rehabilitation group were significantly higher than those in conventional rehabilitation group (with t values of 3.80 and 7.87, respectively, P<0.05). After 12 weeks of home rehabilitation training, the lean body mass of children in combined rehabilitation group was significantly higher than that before home rehabilitation training (t=0.21, P<0.05). After 12 weeks of home rehabilitation training, the 6-min walking distances of children in conventional rehabilitation group and combined rehabilitation group were significantly longer than those before home rehabilitation training (with t values of -5.33 and -3.40, respectively, P<0.05), and the 6-min walking distance of children in combined rehabilitation group was significantly longer than that in conventional rehabilitation group (t=3.81, P<0.05). Conclusions: Conventional burn rehabilitation treatment in hospital and home resistance training with elastic band for 12 weeks after discharge can significantly improve the muscle function and walking ability of severely burned children.

[Long-term outcomes of childhood steroid-sensitive nephrotic syndrome]

Objective: To investigate the long-term outcomes and risk factors in children with steroid-sensitive nephrotic syndrome (SSNS). Methods: A retrospective cohort study was conducted on newly onset SSNS admitted to the Department of Pediatrics of the First Affiliated Hospital of Sun Yat-sen University from January 2006 to December 2010 and 105 cases with follow-up for more than 10 years were included. Clinical data including general characteristics, clinical manifestation, laboratory tests, treatment and prognosis. The primary outcome was the clinical cure, and the secondary outcomes were relapse or ongoing immunosuppressive treatment within the last 1 year of follow-up and complications at the last follow-up. According to the primary outcome, the patients were divided into clinical cured group and uncured group. Categorical variables were compared between 2 groups using the χ² or Fisher exact test, and continuous variables by t or Mann-Whitney U test. Multiple Logistic regression models were used for multivariate analysis. Results: Of the 105 children with SSNS, the age of onset was 3.0 (2.1, 5.0) years, and 82 (78.1%) were boys, 23(21.9%) were girls. The follow-up time was (13.1±1.4) years; 38 patients (36.2%) had frequently relapsing or steroid-dependent nephrotic syndrome (FRNS or SDNS) and no death or progression to end-stage kidney disease. Eighty-eight patients (83.8%) were clinically cured. Seventeen patients (16.2%) did not reach the clinical cure criteria, and 14 patients (13.3%) had relapsed or ongoing immunosuppressive treatment within the last year of follow-up. The proportion of FRNS or SDNS (12/17 vs. 29.5% (26/88), χ²=10.39), the proportion of treatment with second-line immunosuppressive therapy (13/17 vs. 18.2% (16/88), χ²=21.39), and the level of apolipoprotein A1 at onset ((2.0±0.5) vs. (1.7±0.6) g/L, t=2.02) in the uncured group were higher than those in the clinical cured group (all P<0.05). Multivariate Logistic regression analysis showed that patients treated with immunosuppressive therapy had an increased risk of not reaching clinical cure in the long term (OR=14.63, 95%CI 4.21-50.78, P<0.001). Of the 55 clinically cured patients who had relapsed, 48 patients (87.3%) did not relapse after 12 years of age. The age at last follow-up was 16.4 (14.6, 18.9) years, and 34 patients (32.4%) were ≥18 years of age. Among the 34 patients who had reached adulthood, 5 patients (14.7%) still relapsed or ongoing immunosuppressive treatment within the last year of follow-up. At the last follow-up, among the 105 patients, 13 still had long-term complications, and 8 patients were FRNS or SDNS. The proportion of FRNS or SDNS patients with short stature, obesity, cataracts, and osteoporotic bone fracture was 10.5% (4/38), 7.9% (3/38), 5.3% (2/38), and 2.6% (1/38), respectively. Conclusions: The majority of SSNS children were clinically cured, indicating a favorable long-term prognosis. History of treatment with second-line immunosuppressive therapy was the independent risk factor for patients not reaching the clinical cure criteria in the long term. While it is not uncommon for children with SSNS to persist into adulthood. The prevention and control of long-term complications of FRNS or SDNS patients should be strengthened.

[Research progress of the application of metagenomics technology in female reproductive tract diseases]

In recent years, many studies have found that vaginal microbiota is closely related to female reproductive tract diseases. However, traditional microbial culture technology has the defects of long culture cycle and most microorganisms cannot be cultured. The development of metagenomics technique has broken the limitations of culture technology, and has been gradually applied to the study of vaginal microorganisms with the characteristics of high throughput, short time, identification of microbial population structure and gene function. It also provides technical support for elucidating the relationship between vaginal microbiota and female reproductive tract diseases. This article mainly introduces the metagenomics techniques and their applications in prevention, screening and diagnosis of common female reproductive tract diseases, and discusses their promising development and limitations to be overcome.

[Analysis of the development trend of burn discipline from the literature published in Chinese Journal of Burns in 22 years]

Objective: To analyze the literature published in Chinese Journal of Burns (now Chinese Journal of Burns and Wounds) in the last 22 years, and to explore the development trend of burn discipline. Methods: The relevant clinical and research literature published in Chinese Journal of Burns from January 1, 2000 to December 31, 2021 were retrieved through China National Knowledge Infrastructure database. Bibliometrics was used to classify and analyze the literature by research types, involved research fields, and reported causes of injury, and compare them every 3 years according to the year of publication (with literature published in 2021 being included in the last time period). Keywords of all the literature were retrieved, which were corrected and conversed later. CiteSpace 6.1.R2 software was used to visually cluster the included keywords, count high-frequency and high-centrality keywords, and divide the high-frequency keywords by time as before for segment comparison. Results: A total of 4 485 relevant papers were included, with an average of about 204 papers each year. The research types analysis of literature showed that clinical diagnosis and treatment literature had the highest proportion, reaching 65.3% (2 929/4 485), followed by cell experiment and animal experiment literature, accounting for 18.1% (812/4 485) and 13.2% (591/4 485), respectively. The proportion of various research types of the literature in each time period was basically stable. The analysis of the research fields involved in the literature showed that the literature in the field of systemic treatment of burns accounted for the highest proportion, reaching 60.2% (2 699/4 485), followed by the literature in the fields of acute wounds and plastic surgery, accounting for 20.2% (908/4 485) and 7.3% (326/4 485), respectively. The proportion of the literature in the field of systemic treatment of burns decreased from 84.0% (430/512) in 2000-2002 to 40.3% (373/926) in 2018-2021, with a decreasing proportion of 43.7%. While compared with that in 2000-2002, the proportions of literature in the fields of acute wounds, plastic surgery, chronic wounds, and burn rehabilitation were on the rise, with the proportions in 2018-2021 increased by 11.7%, 9.1%, 10.7%, and 5.5%, respectively. In the first 6 time periods, the number of literature in the field of discipline management was few and remained in single digits, but it increased to 49 in 2018-2021. Among the 1 099 literature in the field of systemic treatment of burns with a clear cause of injury, the literature on thermal burns was the most, accounting for 58.5% (643/1 099), followed by the literature on electrical burns and chemical burns, accounting for 19.8% (218/1 099) and 12.6% (138/1 099), respectively. The comparison by time period showed that the proportion of literature reporting thermal burns showed a significant downward trend, while the proportion of literature reporting other causes of injury did not change significantly. A total of 6 822 keywords from 2 236 literature were included for analysis. Visual cluster analysis showed that relevant studies focused on burns, surgical flaps, scars, and wound healing. The top 3 keywords in frequency were burns, wound healing, and surgical flaps, and the top 3 keywords in centrality were burns, scars, and skin transplantation. The comparison by time period showed that the only keyword with a stable frequency in the top 10 ranks was burns; with the passage of time, some keywords such as endotoxin/endotoxins and fibroblasts gradually dropped out of the top 10 ranks, while keywords such as wounds and injuries, surgical flaps, and negative-pressure wound therapy gradually entered the top 10 ranks. Conclusions: Among the literature published in Chinese Journal of Burns during the last 22 years, the literature on systemic treatment of burns and thermal burns has gradually decreased, while the literature on chronic wounds and burn rehabilitation has increased. Surgical flaps, wound healing, and scar prevention and treatment are the current research hot spots in burn discipline.

[Diagnostic and predictive values of three criterias of acute kidney injury in children with chronic kidney disease]

Objective: To compare the consistency in diagnosing and staging acute kidney injury (AKI) in children with chronic kidney disease (CKD) according to three criterias. Methods: Children with CKD hospitalized in the First Affiliated Hospital of Sun Yat sen University from January 2013 to December 2019 were analyzed retrospectively. These patients underwent serum creatinine examination more than twice during hospitalization. The AKI diagnosis and staging were performed for each patient according to the 2007 pRIFLE, 2012 KDIGO and 2018 pROCK criteria respectively. All the children were followed up for 1 year after discharge through outpatient visit, re-hospitalization or online consultation. The clinical characteristics and prognosis of CKD children with or without AKI that were diagnosed by 3 criteria were compared. Analysis of variance and chi-squared tests were used for the comparison among groups. Concordance between the different diagnostic criteria was evaluated using Cohen's kappa coefficient. Result: A total of 2 551 children with CKD were included in this study, with an age of (8±4) years. There were 1 628 boys and 923 girls. Nephrotic syndrome was the most prevalent primary disease (55.4%), followed by lupus nephritis (11.2%) and purpura nephritis (8.2%). Among all stages of CKD, CKD category G1 was the most common type (2 146 cases, 84.1%), followed by CKD category G2 (221 cases, 8.7%). AKI occurence rates according to pRIFLE, KDIGO and pROCK criteria were 33.9% (866/2 551), 26.2%(669/2 551) and 19.5% (498/2 551) respectively (χ²=136.3,P<0.01). The diagnostic consistency within three criteria for AKI was high in children with CKD (κ=0.702), but AKI staging consistency was low (κ=0.329). Both the diagnosis and staging consistency of three AKI criteria were poor in children with CKD category G5 (all κ<0.400). The length of hospital stay (LOS), hospitalization costs, the occurence of intensive care unit (ICU) admission and in-hospital mortality were significantly higher in children with AKI diagnosed by different criteria (P<0.05). After 1-year follow-up, the repeated admission rate and CKD staging progress significantly increased in children with AKI (P<0.05). In children with baseline serum creatinine≥200 μmol/L, compared with children who did not experience AKI during hospitalization, the LOS and the hospitalization costs in children who were diagnosed AKI according to pRIFLE or pROCK criteria was significantly higher (P<0.05). However, there was no significant difference in the LOS and hospitalization costs between children with or without AKI who were diagnosed according to KDIGO criteria (all P>0.05). Conclusions: AKI diagnosed by all of the three criteria (pRIFLE, KDIGO and pROCK criteria) was associated with the poor prognosis in children with CKD. However, in those whose baseline serum creatinine≥ 200 μmol/L, AKI diagnosed by pRIFLE and pROCK criteria could better reflect the poor outcomes than by KDIGO criteria.

[Retrospective study of fiberoptic bronchoscopy airway lavage in the treatment of extremely severe burn patients with severe inhalation injury]

Objective: To explore the clinical effects of fiberoptic bronchoscopy airway lavage (FBAL) in the treatment of extremely severe burn patients with severe inhalation injury. Methods: From January 2015 to January 2019, 47 extremely severe burn patients with severe inhalation injury who were hospitalized in Tongren Hospital of Wuhan University & Wuhan Third Hospital, meeting the inclusion criteria, were recruited in this retrospective cohort study. According to whether or not they were treated with FBAL, the patients were divided into fiberoptic bronchoscopy group (23 cases, 19 males and 4 females) and routine group (24 cases, 20 males and 4 females), with the age of (44±11) and (49±9) years, and the admission time of 4 (3, 4) h and 4 (3, 5) h respectively. The patients in routine group were given routine comprehensive treatment, and the patients in fiberoptic bronchoscopy group were treated with FBAL on the basis of routine comprehensive treatment. The pH value, arterial partial pressure of oxygen (PaO(2)), arterial partial pressure of carbon dioxide (PaCO(2)), arterial oxygen saturation (SaO(2)), oxygenation index, white blood cell count (WBC), neutrophils, blood lactic acid, and procalcitonin (PCT) at admission and on post injury day (PID) 3, 5, 7, and 10, the time of mechanical ventilation, the day of intensive care unit (ICU) stay, the incidence of complications and death within PID 28 were compared between the two study groups. The occurrences of bronchospasm and asphyxia of patients in fiberoptic bronchoscopy group were monitored. Data were statistically analyzed with independent sample t test, Mann-Whitney U test, Bonferroni correction, chi-square test, and Fisher's exact probability test. Results: (1) At admission, the values of pH, PaO(2), PaCO(2), SaO(2), and oxygenation index of patients in the two groups were similar (Z=-0.118, -0.320, -0.362, -2.416, -0.234, P>0.05). On PID 3, 5, 7, and 10, the values of pH, PaO(2), SaO(2), and oxygenation index of patients in fiberoptic bronchoscopy group were significantly higher than those of routine group (Z(3 d)=-4.711, -4.161, -5.525, -2.661; Z(5 d)=-3.489, -4.678, -5.875, -3.599; Z(7 d)=-5.104, -4.619, -5.876, -4.844; Z(10 d)=-4.026, -5.698, -5.877, -4.716; P<0.05 or P<0.01). The PaCO(2) values of patients in fiberoptic bronchoscopy group were significantly lower than those of routine group (Z=-2.895, -3.162, -3.407, -2.831, P<0.05 or P<0.01). (2) At admission and on PID 3, 5, and 7, the values of WBC, blood lactic acid, and PCT of patients in the two groups were similar (Z=-0.830, -0.915, -0.458, -0.648, -1.714, -1.479; -0.330, -0.128, -1.766, -0.494, -1.396, -1.522, P>0.05). On PID 10, the values of WBC, blood lactic acid, and PCT of patients in fiberoptic bronchoscopy group were significantly lower than those of routine group (Z=-3.502, -2.630, -2.662, P<0.05 or P<0.01). At admission, the value of neutrophils of patients in fiberoptic bronchoscopy group was 0.887 (0.862, 0.912), which was similar to 0.887 (0.856, 0.897) in routine group (Z=-0.404, P>0.05). On PID 3, 5, 7, and 10, the values of neutrophils of patients in fiberoptic bronchoscopy group were respectively 0.848 (0.802, 0.867), 0.831 (0.815, 0.849), 0.798 (0.771, 0.849), 0.796 (0.751, 0.869), which were significantly lower than those of routine group [0.882 (0.820, 0.906), 0.871 (0.835, 0.903), 0.845 (0.819, 0.905), 0.881 (0.819, 0.916), Z=-2.756, -2.810, -2.618, -3.033, P<0.05]. (3) The time of mechanical ventilation and the days of ICU stay of patients were shorter in fiberoptic bronchoscopy group than those in routine group (Z=-2.199, t=2.368, P<0.05). Within PID 28, the number of patients with complications was significantly less in fiberoptic bronchoscopy group than in routine group (χ(2)=5.436, P<0.05), while the incidence of death within PID 28 in fiberoptic bronchoscopy group was similar to that of routine group (P>0.05). The airway lavage procedures of patients in fiberoptic bronchoscopy group went well with no bronchospasm or asphyxia occurred. Conclusions: FBAL is effective in treating extremely severe burn patients combined with severe inhalation injury. It can improve the oxygenation status of the lung, reduce the systemic inflammatory reaction of patients, shorten the time of mechanical ventilation and ICU stay, and reduce the incidence of complications.

[The significance of eosinophils in the correlation of upper and lower airway inflammation in patients with chronic rhinitis]

Objective: To explore the predictor of lower airway inflammation among the index of nasal inflammation by investigating the expression and association of eosinophils (EOS) in the upper-lower airways and blood of patients with chronic rhinitis. Methods: A total of 162 patients with allergic rhinitis (AR), 117 patients with non-allergic rhinitis (NAR) and 104 controls were enrolled from June 2010 to December 2013 from General Hospital of Eastern Theater Command, People's Liberation Army. All subjects were required detailed medical history collection and nasal resistance measurement. Skin prick test (SPT), blood total immunoglobin E (tIgE) and blood EOS, nasal lavage and induced sputum EOS, nasal provocation and bronchial provocation test (NPT, BPT), nasal and forced exhaled nitric oxide (NNO, FeNO) were performed in all patients. One-way analysis of variance was used for comparison between groups. LSD t test or Mann-Whitney U test was used for comparison between the two groups. Pearson or Spearman related parameter test was used for correlation analysis. Results: The nasal lavage EOS, NNO, induced sputum EOS, FeNO, blood EOS and tIgE were higher in the AR group than that in the NAR group (3.70[1.20, 14.23]/200 HP vs 1.40[0.20, 3.40]/200 HP, 673.50[466.80, 936.00] ppb vs 455.80[248.10, 705.60] ppb, 2.97[0.00, 10.63]% vs 1.00[0.23, 2.00]%, (49.28±26.37)ppb vs (34.07±19.11)ppb, 4.00[2.00, 7.00]% vs 2.00[1.00, 5.00]%, 208.01[61.70, 387.50] IU/ml vs 43.30[19.00, 122.00] IU/ml, F or χ(2) value was 11.442, 19.440, 70.727, 69.449, 47.453, 46.525, respectively, all P<0.05). But there was no significant difference in nasal resistance, NPT and BPT between the two groups. Nasal lavage EOS in AR group and NAR group was correlated with induced sputum EOS, FeNO, tIgE and blood EOS (r value of AR group was 0.448, 0.202, 0.159, 0.321, r value of NAR group was 0.442, 0.268, 0.268, 0.334, respectively, all P<0.05), but not with BPT. After adjustment for gender, age, height and weight, nasal EOS was positively correlated with sputum EOS. Multiple linear regression analysis showed that nasal EOS, blood EOS and SPT were factors affecting sputum EOS levels. The optimal threshold for nasal EOS to determine induced sputum EOS was 3.30/200 HP by (receiver operating characteristic,ROC) analysis. Conclusion: The nasal EOS is correlated with multiple lower airway and systemic inflammatory markers, and is a risk factor for the induced sputum EOS, which can be used as an inflammation biomarker to predict the lower air inflammation.

Analysis of EEG Lemple-Ziv complexity and correlative aspects before and after treatment of anti-syphilis therapy for neurosyphilis

Objective To investigate the diagnostic value of electroencephalogram (EEG) complexity in patients with neurosyphilis by comparing the changes of electroencephalogram Lempel-Ziv complexity (EEG-LZC) before and after anti-syphilis treatment. Methods The EEG complexity of neurosyphilis patients diagnosed in our hospital from July in 2015 to June in 2017 was analyzed and compared with other diagnostic results such as serology examination and cerebrospinal fluid examination. Results A total of 27 patients were diagnosed, including 19 males and 8 females, of which 6 were mesenchymal(cerebrospinal membrane and meningeal vascular), 16 were parenchymal(paralytic dementia, spinal cord tuberculosis and optic neuropathy), and 5 were asymptomatic. After intensive anti-syphilis therapy, the LZC increased significantly in all patients while the trend and degree of change were consistent with other diagnostic results. Conclusion The LZC can be used as one of the diagnostic indexes meanwhile the trend and degree of its change can be used as the reference index of curative effect to neurosyphilis.

[Application of nasolabial fold wrapped perforator flap in one-stage repairof nasal alar full-thickness defects after tumor resection]

Objective:To explore the application of nasolabial fold wrapped perforator flap in one-stage repair of nasal alar full-thickness defects after external nasal tumor resection.Method:Fifteen csaes of alar full-thickness defects after external nasal tumor resection were repaired with the nasolabial fold wrapped perforator flaps in a one-stage procedure. We detected the blood vessel distribution and exit of the blood vessel with Doppler Ultrasonography before these surgeries，and designed the nasolabial fold wrapped perforator flap according to the area and size of nasal alar defects． The flap with reasonable thickness was able to repair the both sides of defect after being trimmed properly. Meanwhile，the flap could be folded to form a local flap covered or lined with skin. We rotated and transferred the flap to repair nasal alar defect． Result:All the flaps survived and all donor sites healed primarily．After 3 to 36 months of follow-up,the color，texture and thickness of the flaps was similar to those of recipient sites．The scar in donor site was minor．There was little scab skin in the nasal cavity. The cosmetic results was satisfactory. Conclusion:The nasolabial fold wrapped perforator flap has the advantages of reliable blood supply,long pedicle flap,proper thickness,outside the skin and the inner lining. The cosmetic appearance of nose is satisfactory.There was little scab skin in the nasal cavity. Also the sensory function of the external nose was retained. The nasolabial fold wrapped perforator flap technique provides an ideal reconstructive option for the nasal alar full-thickness defect repair at one-stage after tumor resection.

[Differential expression of microRNAs in serum of severe burn patients and analysis of the signaling pathway at early stage]

Objective: To explore differential expression of microRNAs in serum of patients with severe burn and analysis of the signaling pathway at early stage. Methods: In this study, we included three healthy adult volunteers and three patients with severe burn, conforming to the inclusion criteria and hospitalized in Tongren Hospital of Wuhan University & Wuhan Third Hospital in July 2015. Venous whole blood of 6 mL of each burn patient and healthy volunteer was collected at 24 to 48 h post injury of burn patients. The whole blood was divided into burn group and healthy control group. Whole blood of 2 mL of each one was used to determine white blood cell count and neutrophile granulocyte content. Serum was separated from the other whole blood of 4 mL of each one. Half of serum was used to determine content of blood glucose, total protein, and albumin; another half of serum was used to extract total RNA with Trizol method. The differentially expressed microRNA, with differential expression ratio larger than or equal to 1.500 between 2 groups, were screened by microRNA chip technique. Then cluster analysis and functional enrichment analysis of Kyoto encyclopedia of genes and genomes (KEGG) signaling pathway were performed on the differentially expressed microRNAs. Data were processed with t test. Results: (1) Content of white blood cell count, neutrophile granulocyte of whole blood, and blood glucose of serum of patients in burn group was obviously higher than that in healthy control group (with t values from 4.27 to 7.83, P<0.05 or P<0.01). Content of total protein and albumin of serum of patients in burn group was significantly lower than that in healthy control group (with t values respectively -12.80 and -12.36, P values below 0.01). (2)Compared with those in serum of healthy control group, differential expression ratios of 48 microRNAs in serum of burn group were larger than 1.500, with 22 up-regulated microRNAs and 26 down-regulated microRNAs. MicroRNA expression profile in serum of burn group was different from that of healthy control group. (3)Functional enrichment analysis of KEGG signaling pathway showed that compared with those in serum of healthy control group, microRNAs of differential expression in serum of burn group took part in tumor transcription misregulation signaling pathway, tumor proteoglycan signaling pathway, long-term potentiation signaling pathway, tumor associated microRNAs signaling pathway, citrate cycle signaling pathway, tumor necrosis factor signaling pathway, focal adhesion signaling pathway, endocytosis signaling pathway, insulin secretion signaling pathway, and estrogen signaling pathway. Conclusions: MicroRNA expression profile in serum of patients with severe burn is different from that in serum of healthy adults. MicroRNAs of differential expression may take part in important pathophysiological process of energy metabolism, inflammatory response, and regulation of blood glucose at early stage of severe burn.

[Lower airway abnormalities in patients with allergic rhinitis]

Objective: To investigate the characteristics of lower airway abnormalities in allergic rhinitis(AR) patients without asthma. Methods: Between June 2008 and December 2012, 377 consecutive AR patients and 264 healthy subjects were recruited. All subjects underwent meticulous history taking, nasal examination, allergen skin prick test, blood routine test, serum total immunoglobin E assay, induced sputum cell count and differentials, measurement of fractional exhaled nitric oxide (FeNO) and bronchial challenge test. Results: The positive rates in AR patients was 12.2%(46/377) for bronchial provocation test, 49.2%(185/377) for FeNO, 39.0%(147/377) for sputum eosinophilia, 15.6%(40/377) for peripheral blood eosinophilia and 55.4%(209/377) for increased serum total IgE levels, which were consistently and statistically higher than those of healthy controls(P<0.01). The levels of FeNO [35.0 (21.8, 65.9)ppb], induced sputum eosinophil percentage [2.0 (0.0, 7.5)%], peripheral blood eosinophil percentage [2.9 (1.8, 4.5)%] and serum total IgE [178.4 (63.1, 384.0)kU/L] in AR patients were also higher(P<0.01). Compared with healthy controls, patients with AR demonstrated lower levels of FEV₁/FVC%, MMEFpred%, MEF₇₅ pred%, MEF₂₅pred% (all P<0.05). Statistical analysis showed that FeNO, ratio of induced sputum eosinophil percentage and peripheral blood eosinophil percentage had significant correlations with each other(P<0.01), the r value being 0.247, 0.235, 0.355 respectively. Conclusion: AR without asthma is characterized by lower airway inflammation, small airway impairment and bronchial hyperreactivity, features similar to those of asthma.

Osteopontin gene expression in the aorta and the heart of propylthiouracil-induced hypothyroid mice

It is known that there is abnormal osteopontin (OPN) expression at the sites of atherosclerotic lesions. In the Apolipoprotein E gene knockout (ApoE-KO) mouse, a model of the atherosclerotic process, altered cholesterol metabolism with associated increase in OPN expression is evident at 12-22 weeks in the aorta and at 22 weeks in the heart. In this study, we analyzed another animal model of hypothyroid mice created by ingestion of propylthiouracil (PTU). After 2 weeks of PTU ingestion, the animals had significant decreases in thyroid hormones (T3 and T4) and immediate increases in blood lipids/cholesterol. Hypothyroid mice showed 1.3-, 1.5-, 2-fold increases in blood levels of total cholesterol, triglycerides, and low density lipoprotein-cholesterol respectively. Semi-quantitative RT-PCR analysis showed that hypothyroid mice had 1.4- to 2-fold increases of OPN mRNA expression in the aorta and 1.5-fold increases in the heart. Hypothyroid animals treated with T3 (5 microg/day for 6 days) or statin (0.2 mg/30 g for 2 weeks) reduce blood lipids and aortic OPN mRNA expression. Data obtained with ELISA analyses showed 1.5- and 1.7-fold increases in OPN protein in the aorta (10 weeks) and the heart (22 weeks), respectively. This increase is close to the mRNA expression in both tissues of hypothyroid mice. In addition, western blots showed several variants of OPN protein expressed in the aorta and the heart. The decrease in the 70 kDa OPN is accompanied by an increase in 45 kDa OPN in the aorta of hypothyroid mice. In contrast, only 45 kDa OPN is found in the heart of control and hypothyroid mice. These data indicate that the increase of OPN mRNA and protein expression occurs in cardiovascular tissues of hypothyroid mice.

Altered expression of cardiac myosin isozymes associated with the malignant hyperthermia genotype in swine

BACKGROUND

Anesthetic-induced malignant hyperthermia (MH) in humans and pigs is associated with dramatic alterations in cardiac function. However, it remains controversial as to whether MH-associated cardiac symptoms represent a primary difference of myocardium or a secondary alteration consequent to increases in the hyperthermic stress. Here the authors describe changes in myosin isoform expression in the hearts of MH-susceptible pigs with and without prior exposure to halothane.

METHODS

One group of pigs was diagnosed as MH susceptible by halothane challenge and Hal-1843 nucleotide examination. To determine if there is an effect of halothane exposure, another group of pigs was diagnosed by simple MH genotyping without exposure to halothane. After diagnosis and genotyping, animals with and without exposure to halothane were killed to study cardiac myosin isozyme distributions, cardiac myofibrillar adenosine triphosphatase (ATPase) activity, and the steepness of the Ca2+-ATPase activity relation in the hearts of normal and susceptible pigs. The altered myosin isozyme expression was analyzed by pyrophosphate gel electrophoresis.

RESULTS

Malignant hyperthermia-susceptible animals with the prior halothane challenge showed an increased V1 myosin (-44%) expression, increased myofibrillar ATPase activity (-25%) and increased steepness of the Ca2+-ATPase activity relation. Without exposure to halothane, no change of myofibrillar ATPase activity was found in the hearts of different genotyped pigs, but there was a small increase in expression of V1 myosin (-5%) in the mutant (TT).

CONCLUSIONS

The potential modulation of V1 myosin expression occurs in the hearts of MH-susceptible pigs. The added stress by halothane challenge would further cause a V3 --> V1 shift, which may be attributed to the long-term effects of hyperthermic stress.

Transforming growth factor-beta1 gene and protein expression associated with atherogenesis of cholesterol-fed rabbits

Transforming growth factor-beta1 (TGF-1beta) has been shown to modulate both cell proliferation and the synthesis of extracellular matrix by vascular cells. This study was aimed to establish the temporal correlation between TGF-beta1 expression, the expression of the extracellular matrix protein fibronectin, and plaque development during atherogenesis of hypercholesterolemic rabbits. New Zealand White rabbits were fed with 2% cholesterol-supplemented chow for 1 week, 2 weeks, 3 weeks or 6 weeks. TGF-beta1 mRNA and protein expression was examined in serial sections of aorta by in situ hybridization and immunohistochemistry. Fibronectin expression was examined by immunohistochemistry. In the control and 1-week feeding group, the expression of TGF-beta1 mRNA and protein was not apparent. In 2-week feeding group, intimal thickening was detected in which TGF-beta1 mRNA and protein were not clearly observed, either. The 3-week and 6-week feeding groups exhibited fatty streaks in which TGF-beta1 mRNA and protein expression markedly increased as feeding proceeded. Cell type-specific staining indicated that TGF-beta1 was expressed by macrophages as well as smooth muscle cells of the fatty streaks. Immunostaining of fibronectin detected low expression levels in control, 1-week and 2-week feeding groups with pronounced upregulation in the thickened intima and the proximal media in 3-week and 6-week feeding groups. These results implicate a role for TGF-beta1 in modulating fatty streak formation and the synthesis of extracellular protein fibronectin during plaque development.

Experimental infection with bovine herpesvirus-4 enhances atherosclerotic process in rabbits

An association of herpesvirus and atherosclerosis has been suggested by seroepidemiologic studies and detection of the virus in arterial tissues. To facilitate the studies of the pathogenic role of herpesvirus in atherosclerosis, we established a rabbit model of atherosclerosis with bovine herpesvirus type-4 (BHV-4). Forty New Zealand White rabbits were randomly divided into six groups. Groups 1, 2, and 3 were inoculated iv with BHV-4 and control Groups 4, 5, and 6 with normal saline. Groups 1 and 4 were fed a regular diet throughout the experiment; Groups 2 and 5 were fed a diet supplemented with 2% cholesterol for 3 weeks starting at 3 weeks postinoculation; and Groups 3 and 6 with a diet supplemented with 2% cholesterol for 6 weeks starting at 3 days postinoculation. Extensive atherosclerotic lesions in Groups 2, 3, and 6, and small lesions in two rabbits in Group 1 were observed, but no obvious lesions were observed in Groups 4 and 5. BHV-4 DNA was demonstrated by polymerase chain reaction and liquid hybridization in aortic sections, various tissue samples, and peripheral blood mononuclear cells of all infected rabbits. Our studies demonstrated that BHV-4 can accelerate the atherosclerotic process in rabbits, and that experimental infection of rabbits with BHV-4 can be a useful atherosclerosis model.

Cyclic strain stimulates monocyte chemotactic protein-1 mRNA expression in smooth muscle cells

Hemodynamic forces are important determinants for the formation of atherosclerotic plaques. The recruitment of circulating monocytes into the arterial wall is an important step during atherogenesis. Monocyte chemotactic protein-1 (MCP-1) has been shown to be a key factor for monocyte transmigration. This study examined the effects of cyclic strain on MCP-1 mRNA expression levels of cultured rat aortic smooth muscle cells. The MCP-1 mRNA levels of aortic smooth muscle cells first increased as the duration of cyclic strain increased, reaching the maximum at 6-12 h, maintained at high levels throughout the 48-h strain period. To explore signaling pathways mediating cyclic strain-stimulated MCP-1 mRNA expression, we examined the involvement of tyrosine kinase and protein kinase C (PKC). Tyrosine kinase inhibitors, genistein and tyrphostin 51, at 50 microM blocked cyclic strain-stimulated MCP-1 mRNA expression. Preincubation with a PKC activator, phorbol 12-myristate 13-acetate (PMA), 2 microM, for 24 h to downregulate PKC did not decrease cyclic strain-induced MCP-1 mRNA expression. A 6-h incubation with 0. 1 microM PMA to activate PKC, which stimulated MCP-1 expression when applied alone, abolished the stimulatory effects of cyclic strain. A specific PKC inhibitor, calphostin C (0.1 microM), diminished cyclic strain-stimulated MCP-1 mRNA expression. Angiotensin II at 10 or 1,000 nM induced a moderate upregulation of MCP-1 mRNA, and no synergistic effects were observed between angiotensin II and cyclic strain. These results indicate that cyclic strain stimulates MCP-1 mRNA expression in smooth muscle cells through signaling pathway(s) mediated by tyrosine kinase activation.

Effects of palmatine on isometric force and intracellular calcium levels of arterial smooth muscle

The effects of palmatine on isometric force and intracellular free calcium levels ([Ca2+]i) were determined in isolated rat arterial strips. Palmatine dose-dependently relaxed the contractile responses stimulated by phenylephrine (PE) in aortic strips. In contrast, it only partially relaxed aortic strips contracted by 51 mM KCl. Pretreatment with palmatine shifted the dose-response curves of PE both rightwards and downwards in a dose-dependent manner. When Ca2+-free solution and re-addition of Ca2+ were applied to assess PE-induced phasic and tonic contractions, palmatine was found to be effective in inhibiting both contractions. The effects of palmatine on intracellular calcium levels were measured with the bioluminescent calcium indicator aequorin in rat tail artery strips. Palmatine caused a concomitant, dose-dependent decrease in PE-activated isometric force and [Ca2+]i, resulting in small changes in the [Ca2+]i-force relationship. These results suggest that vasodilatory effect of palmatine was mediated by reducing [Ca2+]i as well as affecting [Ca2+]i sensitivity of the contractile apparatus. Palmatine-induced [Ca2+]i decreases appeared to involve decreases in both Ca2+ release from intracellular stores and Ca2+ influx through calcium channels.

Monocyte chemotactic protein-1 gene and protein expression in atherogenesis of hypercholesterolemic rabbits

Monocyte adherence to the endothelium and subsequent migration into the subendothelial space are important early events in atherogenesis. Monocyte chemotactic protein-1 (MCP-1) has been shown to be highly expressed in both human atheroma and advanced atherosclerotic lesions of experimental animals. To establish the temporal correlation between MCP-1 expression and plaque development, we examined the expression of MCP-1 during atherogenesis of hypercholesterolemic rabbits using Northern blot analysis, in situ hybridization, and immunohistochemistry. New Zealand White rabbits were fed with 2% cholesterol-containing diet for 1 day, 3 days, 1 week, 3 weeks or 6 weeks. The plasma levels of total cholesterol were significantly increased 3 days after cholesterol feeding and continued to increase during the entire cholesterol-feeding period. Northern blot analysis showed that MCP-1 mRNA levels remained unchanged following cholesterol feeding for up to 1 week, were higher than control levels at 3-week and increased even higher at 6-week. In situ hybridization showed that after 3 weeks of cholesterol feeding, MCP-1 mRNA expression was up-regulated in newly-formed fatty streaks and parts of tunica media in the presence or absence of fatty streaks. At 6-week, pronounced MCP-1 mRNA expression was detected with similar distribution. In contrast, MCP-1 mRNA was detected only in a few endothelial cells and adventitia in control and experimental groups feeding cholesterol up to 1-week. Immunostaining of serial sections indicated that MCP-1 was expressed by macrophages and smooth muscle cells in rabbits fed with cholesterol for 3 or 6 weeks. No MCP-1 was detected in intima or media in all other groups. These results show that a lag period exists between serum cholesterol increase and upregulation of MCP-1 expression, suggesting that cholesterol modifications (e.g. oxidation) are required to stimulate MCP-1 expression. In addition, MCP-1 expressed by both macrophages and smooth muscle cells during the initial stages of atherosclerosis is likely to contribute to the development of fatty streaks in hypercholesterolemic rabbits.

Perturbation of platelet adhesion to endothelial cells by plasminogen activation in vitro

To investigate whether the endothelium-platelet interactions may be altered by plasminogen activation, cultured human umbilical vein endothelial cells (ECs) were treated with tissue-type plasminogen activator (t-PA) in the presence of plasminogen, and platelet adhesion to ECs was subsequently measured by using a tapered flow chamber. Our results demonstrated that platelets adhered more readily to t-PA treated EC monolayer than to the control monolayer at all shear stress levels tested. This phenomenon was treatment time-dependent and dose-dependent, and it could be blocked by adding plasmin inhibitors, such as epsilon-amino caproic acid and aprotinin. Adherent platelets on t-PA treated EC monolayer underwent more severe shape change than those on the control monolayer. While the extracellular matrix directly treated with t-PA attracted less platelets than the control matrix did, platelet adhesion to the matrix that was produced by t-PA-treated ECs was unaltered. These data suggest that t-PA treatment on ECs compromised antiplatelet-adhesion capability on their apical surface without altering the reactivity of their extracellular matrix towards platelets.

Studies on the function of rho A protein in cardiac myofibrillogenesis

The aim of this study was to provide morphological evidence for the presence of rho A protein in developing cardiomyocytes and to investigate its possible role in myofibrillogenesis. Immunostaining with a monoclonal anti-rho antibody gave a diffuse pattern in the cytosol of cultured cardiomyocytes. Introduction of C3 exoenzyme into the cells by electroporation was used to inactivate rho A protein by ADP-ribosylation. An immunostaining with anti-vinculin, anti-talin, and anti-integrin antibodies showed the focal adhesions in electroporation control cardiomyocytes to be evenly distributed in the ventral sarcolemma; the costameric structure was also detected using these antibodies. In contrast, in C3 exoenzyme treated cells, focal adhesions were disassembled and costamere were absent; in addition, beta-actin-positive, non-striated fibrils were lost and assembly of M-protein, titin, and alpha-actinin into myofibrils was poor, as shown by diffuse and filamentous staining pattern. C3 exoenzyme treatment had a less marked effect on mature cardiomyocytes than on immature cells; in this case, cells became distorted and few myofibrils were seen. The intensity of anti-phosphotyrosine antibody staining of the focal adhesion was also decreased or diffuse in C3 exoenzyme-treated cardiomyocytes, suggesting dephosphorylation of focal adhesion components. We therefore conclude that small G protein rho A plays an important role in myofibril assembly in cardiomyocytes.

Increased ferritin gene expression in atherosclerotic lesions

To identify genes potentially implicated in atherogenesis, a cDNA library was constructed from human atherosclerotic aorta and differentially screened with 32P-labeled-cDNAs prepared from human normal and atherosclerotic aortas. Two cDNA clones exhibiting higher hybridization to the 32P-labeled cDNAs from atherosclerotic vessels were isolated and identified to be genes encoding L-ferritin and H-ferritin, respectively. Northern blot analysis confirmed that the expression of both ferritin genes was notably higher in human and rabbit atherosclerotic aortas than in their normal counterparts. A time-course study illustrated that both L- and H-ferritin mRNAs were markedly increased in aortas of rabbits after feeding with a high cholesterol diet for 6 wk, which was also the time period after which the formation of lesions became evident. In situ hybridization revealed that both L- and H-ferritin mRNAs were induced in endothelial cells and macrophages of human early lesions. The signals were also detected in the smooth muscle cells of advanced lesions. Immunostaining further identified the presence of ferritin protein in atherosclerotic lesions. On the other hand, Prussian blue stain revealed the presence of iron deposits in advanced lesions but not in early human or rabbit lesions. Further experiments with cultured human monocytic THP-1 cells and aortic smooth muscle cells demonstrated that ferritin mRNAs were subjected to up-regulation by treatment with IL-1 or TNF, while TGF, PDGF, and oxidized LDL did not affect the expression of either ferritin gene in both cell lines. Collectively, these results clearly demonstrate that ferritin genes are susceptible to induction in the course of plaque formation.

Protease-susceptible sites and properties of fragments of aortic smooth-muscle myosin

We have examined the protease susceptibility of aortic myosin, the thermal unfolding profiles of myosin rod and light meromyosin (LMM) and the solubility properties of the LMM fragments. Two major protease-susceptible sites were found, located at the head-rod junction and the heavy meromyosin (HMM)-LMM junction. Both tryptic and chymotryptic digestion of aortic myosin rod produced the LMM (80-85 kDa) and short subfragment 2 (S-2) (40-45 kDa) segments, which were similar to those of gizzard myosin rod and differed from the short LMM (70 kDa) and long S-2 (58 kDa) segments produced from skeletal-muscle rod. The thermal unfolding profile of aortic myosin rods exhibited three helix-unfolding transitions, at 47.5, 51 and 54 degrees C, similar to those of gizzard rods yet different from those of skeletal-muscle rods. There was a dramatic difference in the solubility of aortic LMM fragments of various molecular mass, as for gizzard smooth-muscle LMM and rabbit skeletal-muscle LMM. LMM fragments of molecular mass 77 kDa or more were completely insoluble in low-ionic-strength buffer, whereas LMM fragments of molecular mass 73 kDa or less were completely soluble in low-ionic-strength buffer. Proteolytic digestion patterns of LMM showed two additional protease-susceptible sites located 13 and 30 kDa from the ends of the LMM molecule. This suggests the existence of flexible regions within the LMM molecule, which may be responsible for the folded form of aortic myosin.

Cloning and identification of amino acid residues of human phospholipase C delta 1 essential for catalysis

In vitro single point mutagenesis, inositol phospholipid hydrolysis, and substrate protection experiments were used to identify catalytic residues of human phosphatidylinositide-specific phospholipase C delta 1 (PLC delta 1) isolated from a human aorta cDNA library. Invariant amino acid residues containing a functional side chain in the highly conserved X region were changed by in vitro mutagenesis. Most of the mutant enzymes were still able to hydrolyze inositol phospholipid with activity ranging from 10 to 100% of levels in the wild type enzyme. Exceptions were mutants with the conversion of Arg338 to Leu (R338L), Glu341 to Gly (E341G), or His356 to Leu (H356L), which made the enzyme severely defective in hydrolyzing inositol phospholipid. Phospholipid vesicle binding experiments showed that these three cleavage-defective mutant forms of PLC delta 1 could specifically bind to phosphatidylinositol 4,5-bisphosphate (PIP2) with an affinity similar to that of wild type enzyme. Western blotting analysis of trypsin-treated enzyme-PIP2 complexes revealed that a 67-kDa major protein fragment survived trypsin digestion if the wild type enzyme, E341G, or H356L mutant PLC delta 1 was preincubated with 7.5 microM PIP2, whereas if it was preincubated with 80 microM PIP2, the size of major protein surviving was comparable to that of intact enzyme. However, mutant enzyme R338L was not protected from trypsin degradation by PIP2 binding. These observations suggest that PLC delta 1 can recognize PIP2 through a high affinity and a low affinity binding site and that residues Glu341 and His356 are not involved in either high affinity or low affinity PIP2 binding but rather are essential for the Ca(2+)-dependent cleavage activity of PLC.

Conformationally altered aortic myosin light chains

Aorta smooth myosin contains two types of light chain, LC20 and LC17, which fold together with the N-terminal region of each heavy chain to form the globular head region of myosin. We demonstrate an altered conformation of LC20 after its separation from heavy chain by high concentrations of urea, on the basis of the following evidence: 1) A polyclonal antibody against LC20 was not able to recognize this conformationally altered form; 2) Myosin reconstituted from heavy chains and urea-dissociated light chains exhibited extremely low ATPase activity. Circular dichroism unfolding profiles showed that light chains dissociated from heavy chains by SDS appeared to be more stable than those generated by urea dissociation.

Intracellular calcium and myosin light chain phosphorylation during U46619-activated vascular contraction

We investigated the relationship between [Ca2+]i, myosin light chain (LC20) phosphorylation and isometric force in guinea pig aortic strips during contractions activated by a thromboxane A2 analogue, (15S)-hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5Z, 13E-dienoic acid (U46619). Isometric force and [Ca2+]i were measured simultaneously using preloaded aequorin as the intracellular calcium indicator. LC20 phosphorylation levels were determined by two dimensional polyacrylamide gel electrophoresis in parallel preparations. Contractions induced by U46619 were accompanied by increases in [Ca2+]i and LC20 phosphorylation. The chelation of extracellular calcium with 2.5 mM EGTA significantly inhibited U46619-induced increases in [Ca2+]i, isometric force and LC20 phosphorylation. Steady-state force assumed a similar dependence on LC20 phosphorylation for contractions stimulated by potassium depolarization, alpha 1-adrenergic agonist phenylephrine and U46619 either in the presence or absence of extracellular calcium. On the contrary, the [Ca2+]i/force relation revealed that both U46619 and phenylephrine stimulated greater isometric force at lower [Ca2+]i than did KCl depolarization. The addition of a protein kinase C inhibitor, 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7), decreases force without significantly affecting either [Ca2+]i or LC20 phosphorylation levels. These results suggest that in guinea pig aortic smooth muscle U46619 increases the calcium sensitivity of the contractile apparatus but does not change the LC20 phosphorylation/force relation in comparison to K+ depolarization. Protein kinase C is activated during U46619-stimulated contraction and might be involved in mechanisms other than LC20 phosphorylation.

Acetylpolyamines decrease blood pressure, [Ca++]i and isometric force of vascular smooth muscle

Polyamines are polycations in cells and acetylation is the first step in their intracellular metabolism. We investigated the effects of the acetylated polyamines on arterial blood pressure and vascular reactivities in rats. Acetylspermine and acetylspermidine, administered at concentrations ranging from 12.5 to 50 mmol/kg b.wt., both induced a transient decrease in mean arterial blood pressure. The magnitudes of the hypotensive effects of these acetylpolyamines and polyamines were in the order of spermine > acetylspermine > acetylspermidine = spermidine. Pretreatment of rats with calcium diminished polyamine-induced hypotensive effects. The effects of spermine and acetylspermine on isolated vascular smooth muscle were examined in rat aortic rings and tail artery strips. Both compounds relaxed precontracted arterial preparations, and this relaxation could be counteracted by increasing extracellular calcium concentration. Tail artery strips were more sensitive to acetylspermine when compared to aortic rings. In tail artery strips preloaded with the bioluminescent protein aequorin, both spermine and acetylspermine caused a concomitant decrease in intracellular calcium and isometric force activated by 36 mM of KCl. These results demonstrate clearly that acetylspermine and spermine alike decrease intracellular calcium concentration of vascular smooth muscle, which is likely to account for the relaxation of vasculature. The relaxation of smooth muscle in the vascular wall in turn might lead to decreased arterial blood pressure.

Pathophysiologic role of calcium in the development of vascular smooth muscle tone

Recent information indicates that the intracellular ionized calcium concentration [Ca2+]i plays a regulatory role not only in determining the magnitude of vascular tone but also in regulating growth of vascular tissue. Studies on living vascular smooth muscle cells using the calcium indicator aequorin have revealed that the relation between [Ca2+]i and contraction of the vascular smooth muscle cell is complex. More than 1 intracellular kinase may be involved, leading to the coexistence of multiple excitation-contraction coupling pathways. However, it appears that all of these pathways may be calcium-dependent. It is not yet known whether the cause of human essential hypertension involves an elevated [Ca2+]i in the vascular smooth muscle cell. However, evidence is presented supporting the concept that a decreased [Ca2+]i in the hypertensive smooth muscle cell will lead to a decrease in vascular tone and total peripheral resistance, and possibly also antagonize the growth response of the vascular smooth muscle cell associated with the secondary effects of hypertension.

Agonist-specific myosin phosphorylation and intracellular calcium during isometric contractions of arterial smooth muscle

The relationship between phosphorylation of the 20-kDa myosin light chain, intracellular calcium levels ([Ca2+]i), and isometric force was studied during prolonged activation of arterial smooth muscle. Aequorin, preloaded into ferret aortic strips, was used as a [Ca2+]i indicator. Two dimensional polyacrylamide gel electrophoresis was used to determine the phosphorylation levels of the 20-kDa myosin light chain (LC20). During the 30-min depolarization of arterial smooth muscle by K+ (21 mM), both LC20 phosphorylation and [Ca2+]i increased significantly at all time points examined as did the steady state stress. A transient rise in LC20 phosphorylation and [Ca2+]i occurred within 30 s, followed by suprabasal levels through the 10-min period during a sustained alpha 1-mediated activation by 10(-5) M phenylephrine whereas a higher force was developed at a shorter time compared to K+. An active phorbol ester 12-deoxyphorbol 13-isobutyrate 20-acetate (DPBA, 10(-6) M) induced a slow contraction of similar magnitude to that induced by K+ without significantly changing either [Ca2+]i or LC20 phosphorylation over a 90-min period. These results demonstrate that the amount of LC20 phosphorylation correlates with the [Ca2+]i in all three types of activation. The initial levels of [Ca2+]i and LC20 phosphorylation correlate with the onset of force development but not the magnitude of steady state stress, suggesting a role for [Ca2+]i and LC20 phosphorylation in regulating the cross bridge cycling rate during tension development. The lack of a detectable increase in [Ca2+]i and LC20 phosphorylation during DPBA activation suggests that sites other than LC20, phosphorylated by protein kinase C, may be involved in regulating smooth muscle contraction.

Intracellular calcium levels in phorbol ester-induced contractions of vascular muscle

Intracellular calcium concentration ([Ca2+]i) was measured with aequorin in ferret and rat aortic strips contracted with phorbol esters. In ferret aorta, 12-deoxyphorbol 13-isobutyrate 20-acetate (DPBA, 1 microM) induced contractions without significantly increasing [Ca2+]i, whereas 21 mM K+ induced smaller contractions with a significant rise in [Ca2+]i. Ca2+-free 2.5 mM ethyleneglycol-bis(beta-aminoethylether)-N,N'-tetraacetic acid (EGTA)-physiological saline solution (PSS) had no effect on DPBA-induced tension, whereas it abolished contractions induced by 66 mM K+. The alpha 1-adrenergic agonist phenylephrine (10(-5) M) induced less than 10% of the tension with no initial [Ca2+]i spike under Ca-free conditions. In rat aorta, both phorbol 12-myristate 13-acetate (PMA, 2 microM) and DPBA (1 microM) induced contractions without increasing [Ca2+]i; Ca2+-free EGTA-PSS or the addition of the calcium channel blocker gallopamil (D600, 1 microM), however, abolished greater than 50% of the tension induced by either phorbol ester with a decrease in [Ca2+]i. These results are consistent with the idea that 1) resting [Ca2+]i is both sufficient and required to support phorbol ester-induced contractions in two vascular smooth muscles, suggesting an increased sensitivity of the contractile apparatus for Ca2+, and 2) there are differences in the mechanisms by which phorbol esters and alpha 1-agonists may activate vascular smooth muscle.

Properties and function of phosphatases from vascular smooth muscle

Myosin light chain phosphatase (MLCP) activity was present in extracts from a wide variety of mammalian tissues. A partially purified preparation of bovine aortic MLCP also showed activity against phosphorylase a and p-nitrophenyl phosphate (PNP). Whether these three activities are ascribable to a single multifunctional phosphatase or to three distinct phosphatases is unknown. The three phosphatase activities coelute during gel filtration both before and after treatment with ethanol showing exclusion volumes corresponding to 240,000 and 35,000 daltons, respectively. This indicates that the enzyme is dissociable into a smaller catalytic subunit. The widespread occurrence of MLCP activity and the close parallel among MLCP, phosphorylase a phosphatase, and PNP phosphatase activities suggest that the enzyme (or enzymes) may participate in physiological processes in addition to dephosphorylation of phosphorylated myosin light chains.

Cytoplasmic and nuclear binding of estradiol in the brain and pituitary of old female rats

The subcellular distribution of estradiol following the in vivo administration of 3H-estradiol, cytosol and nuclear estrogen receptor after in vitro incubation with 3H-estradiol were studied in young adult female rats (3-6 months old) and old female rats (over 18 months old). After intravenous injection of 3H-estradiol, with or without deithylstilbestrol pretreatment, significantly higher cytosol uptake of estradiol in the pituitary, dorsal hypothalamus and corticomedial amygdala (AMYG) with concomitant significantly lower nuclear uptake in the preoptic area (POA) and basomedial hypothalamus (BMH) and a tendency of lower nuclear uptake in AMYG and pituitary of old noncyclic (NC) rats as compared with young adult female rats were observed. The uterus of NC rats had a low ratio of milligrams of protein per milligram wet weight as compared with young rats and the nuclear binding 1 h after the injection was significantly lower than that of young rats when the value was expressed as disintegrations per minute per milligram weight but not when expressed as disintegrations per minute per milligram protein. Assays of cytosol and nuclear estrogen receptor after in vitro incubation with 3H-estradiol revealed that old prolonged vaginal cornification (PVC) rats did not react estradiol priming with increased nuclear receptors in the pooled brain tissues of AMYG, POA and BMH, anterior pituitary and uterus. These results indicate that there seems to be an impaired translocation of estradiol from cytosol to nucleus in old PVC rats.

Changes in running-wheel activity, eating and drinking and their day/night distributions throughout the life span of the rat

Running-wheel activity, eating and drinking of 39 male Long-Evans rats of various ages ranging from four to 33 months old, were recorded twice a day and total activity, and food and water intake per day and percentage nocturnal activity were studied. Running activity and food intake decrease as age advances and water intake first decreases from four months to 17 months of age and later increases proportionally with further increases in age. The percentage of nocturnal activity of the running-wheel decreases from 12 months of age proportionally with an increase of age; food and water intake also have this tendency. However, incidence of disappearance of diurnal difference in running activity, eating and drinking is quite low (7%, 32% and 25% respectively). Seven long-term ovariectomized Sprague-Dawley rats over 24 months of age show similar results to those with male Long-Evans rats. Reversal of the lighting schedule does not induce a phase shift of running activity, eating and drinking in two among 15 rats over 18 months of age, seven among 21 rats and four among 21 rats, respectively. Other rats over 18 months of age can recover their light/dark rhythm in a period not significantly different from rats below 13 months of age. The neuron number of the suprachiasmatic nucleus does not have significant correlations with percentage nocturnal activity in running activity, eating and drinking.