Fabrication and evaluation of porous coatings doped with bioactive elements on titanium surfaces.

OBJECTIVE: Although pure titanium (PT) and its alloys exhibit excellent mechanical properties, they lack biological activity as implants. The purpose of this study was to improve the biological activity of titanium implants through surface modification. MATERIALS AND METHODS: Titanium was processed into titanium discs, where the titanium discs served as anodes and stainless steel served as cathodes, and a copper- and cobalt-doped porous coating [pure titanium model (PTM)] was prepared on the surface of titanium via plasma electrolytic oxidation. The surface characteristics of the coating were evaluated using field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and profilometry. The corrosion resistance of PTM was evaluated with an electrochemical workstation. The biocompatibility and bioactivity of coated bone marrow mesenchymal stem cells (BMSCs) were evaluated through in vitro cell experiments. RESULTS: A copper- and cobalt-doped porous coating was successfully prepared on the surface of titanium, and the doping of copper and cobalt did not change the surface topography of the coating. The porous coating increased the surface roughness of titanium and improved its resistance to corrosion. In addition, the porous coating doped with copper and cobalt promoted the adhesion and spreading of BMSCs. CONCLUSIONS: A porous coating doped with copper and cobalt was prepared on the surface of titanium through plasma electrolytic oxidation. The coating not only improved the roughness and corrosion resistance of titanium but also exhibited good biological activity.

Clinical effect of open reduction and internal fixation with a steel plate through the triceps approach in the treatment of fractures of the middle and lower 1/3 of the humerus.

OBJECTIVE: The stability of fractures of the middle and lower 1/3 of the displaced humeral shaft is poor, and surgery is currently the main treatment. The posterolateral approach to the upper arm has many advantages but it is not widely used in clinical applications. The aim of the study was to investigate the clinical effect of open reduction and internal fixation with a steel plate through the triceps approach in the treatment of fractures of the middle and lower 1/3 of the humerus. PATIENTS AND METHODS: A retrospective analysis was performed on 26 patients with fractures of the middle and lower 1/3 of the humerus who were admitted to our hospital from January 2018 to December 2021. According to the AO ASIF classification, 12 patients had type A, 8 patients had type B, and 6 patients had type C fractures. The posterior transtriceps approach was used for open reduction and internal fixation with a steel plate to evaluate its clinical efficacy. RESULTS: All patients were followed completely, and the follow-up time was 6.0-18.0 months. Fracture nonunion occurred in 1 patient after the operation, and the other 25 patients healed well; 2 patients showed symptoms of radial nerve injury and numbness in the tiger's mouth area, which improved after 2 weeks. The average healing time of the fracture was 12.3 weeks. There were no infections or complications such as plate fractures. Elbow joint function according to Mayo scoring standards was as follows: 19 cases were excellent, 3 cases were good, 2 cases were fair, and 2 cases were poor. The excellent and good rate was 84.6%. CONCLUSIONS: Open reduction through the triceps approach and internal fixation with a steel plate for the treatment of the middle and lower 1/3 of the humerus can directly expose and protect the radial nerve and its branches and reduce radial nerve damage, and plate fixation on the tension side is biomechanical and worthy of clinical application.

Clinical effect of unilateral balloon infusion of low dose bone cement in PKP for osteoporotic thoracolumbar compression fractures in the elderly.

OBJECTIVE: The study was undertaken to determine the clinical effectiveness of percutaneous kyphoplasty (PKP) with unilateral balloon infusion of low dose of bone cement for treatment of osteoporotic vertebral compression fractures (OVCFs) in the elderly. PATIENTS AND METHODS: A retrospective study was carried out. A total of 36 patients with OVCFs treated by PKP from August 2019 and August 2020 were included. Patients were divided into two groups according to the amount of bone cement infused into the vertebral body. The amount of cement in conventional-dose group was 3.5-6.0 mL and the amount of cement in small-dose group was 1.8-3.0 mL. Pain relief before and after the operation were evaluated, and the leakage of bone cement in the two groups was also observed. RESULTS: Two groups of patients have obtained a good clinical efficacy. Pain has significant differences before and after the operation (p < 0.05). More importantly, compared with conventional-dose group, small-dose group has lower bone cement leakage rate (p < 0.05). CONCLUSIONS: PKP with small-dose bone cement infusion can obtain the same clinical effects of conventional-dose, but the incidence of bone cement leakage is lower and safe.

Clinical effect of cement-enhanced APFN in the treatment of elderly osteoporotic intertrochanteric fractures.

OBJECTIVE: To explore the clinical effect of bone cement-enhanced Asian proximal femoral anti-rotation intramedullary nail (APFN) internal fixation in the treatment of elderly osteoporotic intertrochanteric fractures of the femur and provide it as a more robust treatment to elderly patients with osteoporotic intertrochanteric femoral fractures. PATIENTS AND METHODS: Between January 2017 and January 2019, 42 patients with osteoporotic intertrochanteric fractures in our hospital were selected. All patients were randomly divided into the proximal femoral anti-rotation intramedullary nail (PFNA) group and APFN group. The PFNA group received conventional PFNA internal fixation, and the APFN group received bone cement-enhanced APFN internal fixation. The operation time, intraoperative blood loss, average fracture healing time, weight bearing time, and hip function recovery of the two groups of patients were evaluated. RESULTS: All patients were followed up. There was no significant difference in intraoperative blood loss between the two groups. Compared with the PFNA group, the weight-bearing time and hospital stay of the APFN group were significantly shorter. According to the Harris score of hip joint function, the excellent and good rate of the APFN group was better than that of the PFNA group. CONCLUSIONS: Compared with conventional PFNA internal fixation, cement-enhanced APFN internal fixation has the advantage of early functional reconstruction in the treatment of osteoporotic femoral intertrochanteric fractures. It can significantly shorten the time required for patients to get out of bed and bear weight. It is an effective method for the treatment of osteoporotic femoral intertrochanteric fracture.

Effect of concentrated growth factor on lower lip hypoesthesia after osseous genioplasty: a prospective, split-mouth, double-blind randomized controlled trial.

Lower lip hypoesthesia is the most common complication following osseous genioplasty. Concentrated growth factor (CGF) has recently been shown to improve neural regeneration. The aim of this study was to evaluate the effect of concentrated growth factor on neurosensory recovery after osseous genioplasty. Patients who underwent osseous genioplasty between June 2017 and February 2020 were enrolled. CGF was applied to the mental nerve on one side. The treatment side was randomized, and the other side was considered as the control. Lower lip hypoesthesia was assessed preoperatively and postoperatively (1 week, 1, 3, 6, and 9 months) using the two-point discrimination test and a 10-point visual analogue scale (self-reported paresthesia). The assessor was blinded. Twenty-six female patients completed the study. At 1 and 3 months, both the mean two-point discrimination value and mean visual analogue scale score were significantly lower in the CGF group than in the control group (P < 0.001). At 3 months, the percentage of patients with lower lip hypoesthesia in the CGF group was significantly lower than that in the control group (P < 0.001). Both groups showed resolution of lower lip hypoesthesia at 6 months. Concentrated growth factor may accelerate the recovery of long-standing sensory nerve impairment following mental osteotomy.

[Retrospective analysis of infliximab in the treatment of Kawasaki disease].

Objective: To investigate the efficacy and safety of infliximab (IFX) therapy for children with Kawasaki disease. Methods: Sixty-eight children with Kawasaki disease who received IFX therapy in Children's Hospital of Fudan University from January 2014 to April 2021 were enrolled. The indications for IFX administration, changes in laboratory parameters before and after IFX administration, response rate, drug adverse events and complications and outcomes of coronary artery aneurysms (CAA) were retrospectively analyzed. Comparisons between groups were performed with unpaired Student t test or Mann-Whitney U test or chi-square test. Results: Among 68 children with Kawasaki disease, 52 (76%) were males and 16 (24%) were females. The age of onset was 2.1 (0.5, 3.8) years. IFX was administered to: (1) 35 children (51%) with persistent fever who did not respond to intravenous immunoglobulin (IVIG) or steroids, 28 of the 35 children (80%) developed CAA before IFX therapy; (2) 32 children (47%) with continuous progression of CAA; (3) 1 child with persistent arthritis. In all cases, IFX was administered as an additional treatment (the time from the onset of illness to IFX therapy was 21 (15, 30) days) which consisted of second line therapy in 20 (29%), third line therapy in 20 (29%), and fourth (or more) line therapy in 28 (41%). C-reactive protein (8 (4, 15) vs. 16 (8, 43) mg/L, Z=-3.38, P=0.001), serum amyloid protein A (17 (10, 42) vs. 88 (11, 327) mg/L, Z=-2.36, P=0.018) and the percentage of neutrophils (0.39±0.20 vs. 0.49±0.21, t=2.63, P=0.010) decreased significantly after IFX administration. Fourteen children (21%) did not respond to IFX and received additional therapies mainly including steroids and cyclophosphamide. There was no significant difference in gender, age at IFX administration, time from the onset of illness to IFX administration, the maximum coronary Z value before IFX administration, and the incidence of systemic aneurysms between IFX-sensitive group and IFX-resistant group (all P>0.05). Infections occurred in 11 cases (16%) after IFX administration, including respiratory tract, digestive tract, urinary tract, skin and oral infections. One case had Calmette-Guérin bacillus-related adverse reactions 2 months after IFX administration. All of these adverse events were cured successfully. One child died of CAA rupture, 6 children were lost to follow up, the remaining 61 children were followed up for 6 (4, 15) months. No CAA occurred in 7 children before and after IFX treatment, while CAA occurred in 54 children before IFX treatment. CAA regressed in 23 (43%) children at the last follow-up, and the diameter of coronary artery recovered to normal in 10 children. Conclusion: IFX is an effective and safe therapeutic choice for children with Kawasaki disease who are refractory to IVIG or steroids therapy or with continuous progression of CAA.

[The value of (18)F-fluorodeoxyglucose positron emission tomography-computed tomography ((18)F-FDG PET-CT) in evaluating the stability of atherosclerotic plaques].

Objective: Positron emission tomography-computed tomography (PET-CT) has been used to quantify inflammatory response in the body. The aim of the present study was to explore the possibility of using this method to evaluate the stability of atherosclerotic plaques and the efficacy of atorvastatin in stabilizing atherosclerotic plaques. Methods: Twenty New Zealand male white rabbits were included and divided into the atorvastatin intervention group and the control group, with 10 rabbits in each group. Rabbits in both groups were fed with a high fat diet for 20 weeks, and treated with thoracoabdominal aortic balloon-pulling to establish atherosclerosis model at the end of the 2nd week. Rabbits in atorvastatin intervention group was given atorvastatin intragastrically once a day. At the 8th week, thoracoabdominal aortic ultrasound was used to detect plaques in all rabbits. Blood was drawn at the 3rd and the 20th week, respectively, to measure blood lipids, high-sensitive C-reactive protein (hs-CRP) and matrix metalloproteinase-9 (MMP-9). At the end of experiment, survival animals were scanned by (18)F-FDG PET-CT, and the average and maximum standard uptake values (SUVmean, SUVmax) of aortic segments were measured. Thereafter, the animals were sacrificed and aortic specimens of rabbits were taken and examined by immunohistochemistry. The pathological indexes were measured and compared. Results: At the end of experiment, the total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), hs-CRP [ (4.58±0.51) ng/ml vs.(5.87±0.66) ng/ml, P<0.01], MMP-9[ (43.93±2.16) ng/ml vs. (50.77±2.32) ng/ml, P<0.01], SUVmean (0.59±0.15 vs. 0.68±0.20, P<0.05) , SUVmax (0.68±0.20 vs. 0.81±0.27, P<0.05) , plaque area [ (0.36±0.24) mm(2) vs. (0.50±0.34) mm(2), P<0.05) ] and density of macrophage[ (4.34±1.54) % vs. (5.65±1.89) %, P<0.01] in the atorvastatin intervention group were significantly lower than those in the control group. In contrast, fiber cap thickness of the plaque[ (4.12±0.66) µm vs. (2.96±0.37) µm, P<0.01] in the atorvastatin intervention group was higher than that of the control group, and the difference was statistically significant. The arterial plaque areas were positively correlated with SUVmean (r=0.27, P<0.05) and SUVmax (r=0.43, P<0.01) . Fiber cap thickness was negatively correlated with SUVmean (r=-0.38, P<0.05) and SUVmax (r=-0.47, P<0.01) . The density of macrophage were positively correlated with SUVmean (r=0.52, P<0.01) and SUVmax (r=0.51, P<0.01) . Conclusion: (18)F-FDG PET/CT can be used to evaluate the efficacy of atorvastatin by the stability of atherosclerotic plaques.

[Comparison of safety between continued warfarin therapy and bridging anticoagulation therapy in patients undergoing coronary intervention].

Objective: To compare the safety of continued warfarin therapy and bridging anticoagulation therapy during hospital stay in patients undergoing percutaneous coronary intervention (PCI). Methods: We retrospectively analyzed patients on warfarin therapy referred for PCI in Beijing Anzhen Hospital from January 2008 to December 2016. The patients were divided into continued warfarin therapy (n=195) or bridging anticoagulation therapy (n=311) groups. After Propensity Score Matching, data from matched patients (n=123 in each group) were analyzed. Bleeding complications and major adverse cardiac events including death, myocardial infarction, target vessel revascularization, and stent thrombosis were assessed. Results: There were no significant difference in the rate of death (2.4%(3/123) vs. 1.6%(2/123),P=0.54), acute myocardial infarction (4.1%(5/123) vs. 4.9%(6/123), P=0.78),re-revascularization (0.8%(1/123) vs. 1.6%(2/123),P=0.16), stent thrombosis (1.6%(2/123) vs. 1.6%(2/123),P=1.00) and stroke between the two groups. Prevalence of minor bleeding complications was significantly higher in the bridging therapy group (15.4%(19/123) vs. 9.8%(12/123),P=0.01). Rate of access-site complications (hematoma:4.1%(5/123) vs. 2.4%(3/123),P=0.20; pseudoaneurysm:2.4%(3/123) vs. 2.4%(3/123),P=1.00; arteriovenous fistula:0.8%(1/123) vs. 1.6%(2/123),P=0.09; and retroperitoneal hematoma:0(0/123) vs. 0.8%(1/123),P=0.23) were similar between the two groups. Conclusion: For patients receiving chronic warfarin therapy, the uninterrupted oral anticoagulant treatment is as safe as bridging therapy in PCI patients.

[Assessment of undiagnosed critical congenital heart disease before discharge from the maternity hospital].

Objective: Undiagnosed critical congenital heart disease (CCHD) was assessed before discharge from maternity hospital.Basic information was provided for screening CCHD in the early neonatal stage.Chi-squared test was used for comparison of categorical variables(detection rate of different types of CCHD). Method: A retrospective cohort study was conducted in neonates with CCHD who were admitted to Children's Hospital of Fudan University between 1 January 2012 and 31 December 2015. For comparing with the previously reported undiagnosed rate of CCHD at discharge, CCHD was defined as all duct dependent congenital heart disease (DDCHD) and any cyanotic CHD that required early surgery. Result: A total of 1 036 infants with CCHD were included. The prenatal detection rate of CCHD was 14.04%(122/869). As a whole, 52.51% (544/1 036) of CCHD cases were undiagnosed at discharge, and 14.09%(146/1 036)were still missed after 6-week examination. The diagnoses most likely to be unrecognized at discharge included critical coarctation of the aorta (COA) (75.00%), total anomalous pulmonary venous connection (61.54%), pulmonary atresia (PA) with ventricle septal defect (VSD) (61.45%), single ventricle (SV) (60.10%) and critical aortic stenosis (52.94%). Among newborns diagnosed prior to discharge, 54.88% (270/492) due to symptom or prenatal ultrasonographic diagnosis, 45.12% (222/492) due to abnormal findings in routine examination. Among asymptomatic CCHD cases without prenatal diagnosis, 71.02% (544/766) were undiagnosed and the most common delayed diagnosis was SV (82.78%), interrupted aortic arch (81.82%), transposition of the great arteries with intact ventricular septum (79.63%), PA/VSD (79.07%), and critical COA (78.57%). Newborns with DDC were more likely to develop symptoms within the first few days after birth, in comparison with non-DDC cases. However, their detection rates were close to each other. Conclusion: The rate of misdiagnosis of CCHD before discharge from maternity hospitals is high in China, indicates the importance of implementation of CCHD screening in Chinese maternity hospitals, so as to give timely diagnosis and proper treatment.

Monitoring of atherosclerosis evolution by detection of inflammatory states of aortae in a rabbit model using 18F-FDG -PET/CT.

AIM: In vivo dynamic evaluation of atherosclerosis could be clinically significant in the prevention of cardiovascular events. We aimed to monitor Fluorine-18 fluorodeoxyglucose (18F-FDG) uptake in different stages of atherosclerosis, and investigate the feasibility of detecting vulnerable plaques using positron emission tomography/computed tomography (PET/CT) angiography. METHODS: Twenty-two male NZW rabbits were divided into two groups: atherosclerosis group (group A, N.=11) and atherosclerosis and statin group (group S, N.=11). The rabbits underwent two pharmacological triggerings to induce thrombus at the 18th week. In vivo PET/CT scans were performed on four time points: before cholesterol diet (baseline, N.=6), at 8th week (the middle-of-feeding, N.=4), at 18th week (the end-of-feeding, N.=22) and after triggering (post-triggering, N.=15). 18F-FDG uptake by the aorta was expressed as maximal standardized uptake value (SUVmax) and mean SUV (SUVmean). SUVs were measured on serial 7.5 mm arterial segments. RESULTS: SUVmean and SUVmax were 0.449±0.108 and 0.550±0.132 at baseline, 0.694±0.117 and 0.754±0.129 at the middle-of-feeding, 0.788±0.121 and 0.861±0.139 in group A, and 0.651±0.194 and 0.736±0.243 in group S at the end-of feeding before triggering. SUVmean and SUVmax were 1.128±0.420 and 1.302±0.489 in thrombosis group, 0.774±0.159 and 0.859±0.191 in non-thrombosis group after triggering. Thrombus were identified in 10 of 22 rabbits (45.5%): 8 of 11 (72.3%) in group A, and 2 of 11 (18.2%) in group S (P<0.001). CONCLUSION: The inflammatory states of atherosclerosis and vulnerable plaque can be detected by quantitative analysis of 18F-FDG uptake. PET/CT may be used for predicting thrombosis events in patients with atherosclerotic disease.

Lyme borreliosis caused by diverse genospecies of Borrelia burgdorferi sensu lato in northeastern China.

The variety of Borrelia burgdorferi sensu lato (B. burgdorferi) genospecies leads to distinction in clinical manifestations of Lyme borreliosis (LB). There are reports of LB clinical characteristics in China, where the B. burgdorferi genospecies in ticks and animal hosts are different from those in Europe and North America. During May to September in 2010 and 2011, all patients who had erythema migrans (EM, more than 5 cm in diameter) after a recent tick-bite, and sought medical care at Mudanjiang Forestry Central Hospital, Heilongjiang Province of northeastern China, were enrolled in the study. Specific PCR was used to determine the B. burgdorferi genospecies in the disseminated patients. Of 265 EM patients, B. burgdorferi DNA was detected in blood specimens from 15 of 55 disseminated patients. Sequence analyses of 5S-23S rRNA, flagellin, ospC, 16S rRNA and ospA genes revealed that 11 patients were infected with Borrelia garinii, three with Borrelia afzelii and one with Borrelia valaisiana-related genospecies. Among 15 patients, 40%, 13.3% and 13.3% manifested pruritus, pain and ulceration, respectively. Systemic symptoms, arthralgia or a swollen joint and lymphadenopathy were observed in 26.7%, 13.3% and 6.7% patients, respectively. In northeastern China, three genospecies of LB patients were detected. The B. burgdorferi genospecies identified in this study was predominantly B. garinii. A case infected with B. valaisiana-related genospecies was reported for the first time.

Sequence variations in the MBL gene and their relationship to pulmonary tuberculosis in the Chinese Han population.

SETTING: The mannan binding lectin (MBL) gene is thought to play a role in human innate immune response to tuberculosis (TB) infection. OBJECTIVE: To investigate the possible association between MBL sequence variants and TB infection in the Chinese Han population. DESIGN: A total of 152 male pulmonary tuberculosis (PTB) patients and 293 healthy male subjects were recruited. Six MBL single nucleotide polymorphisms (SNPs) (A/B, A/C, A/D, H/L, Y/X and P/Q) were genotyped and haplotyped using the combined analysis of polymerase chain reaction using sequence-specific primers (PCR-SSP) and the PCR-sequence specific oligonucleotide probe (PCR-SSOP) assay. The genotype and haplotype frequencies were compared between TB cases and controls using an unconditional logistic regression model. RESULTS: Neither the genotypes nor the haplotypes of the five loci were significantly associated with the disease when considered individually. After the haplotypes were regrouped, however, the XB haplotype group coding for diminished MBL levels was present at a significantly higher frequency in the patients compared with the YA group (OR 1.57, 95% CI 1.02-2.41, P < 0.05). CONCLUSION: No convincing evidence of association between MBL sequence variants and PTB was observed individually, although the low-producing XB haplotype group may serve as a minor risk factor for PTB infection in the male Chinese Han population.

VDR and NRAMP1 gene polymorphisms in susceptibility to pulmonary tuberculosis among the Chinese Han population: a case-control study.

OBJECTIVE: To explore the potential role of vitamin D receptor (VDR) gene and natural-resistance-associated macrophage protein 1 (NRAMP1) gene polymorphisms in susceptibility to pulmonary tuberculosis (PTB) in the Chinese Han population. DESIGN: In an unmatched case-control study, 120 well defined PTB patients and 240 unrelated normal controls were enrolled. Information on potential risk factors of PTB was collected using a standard questionnaire. Genetic polymorphisms of VDR gene (TaqI and FokI) and NRAMP1 gene (INT4, D543N and 3'UTR) were analysed using PCR and RFLP. Unconditional logistic regression was performed, and odds ratios (ORs), their 95% confidence intervals (CI) and P values were estimated using maximum likelihood methods. RESULTS: Univariate analysis demonstrated that FokI-ff homozygotes, D543N G/A and 3'UTR TGTG+/del heterozygotes occurred more frequently in patients than in controls. The crude ORs were 2.345 (95%CI 1.222-4.499), 2.590 (95%CI 1.043-6.434) and 1.890 (95%CI 1.171-3.051), respectively, compared with their corresponding common genotypes. The P values were 0.033, 0.041 and 0.030, respectively. After adjusting for exposure history and BCG immunisation in the multivariate analysis, the adjusted ORs were 4.625 (95%CI 1.737-12.312), 2.415 (95%CI 1.079-8.759) and 2.187 (95%CI 1.146-4.175), with P values of 0.002, 0.036 and 0.018, respectively. Neither univariate nor multivariate analysis disclosed any significant association between the disease and TaqI or INT4. CONCLUSIONS: Polymorphisms in the VDR and NRAMP1 gene are statistically associated with susceptibility to PTB in the Chinese Han population.

Exercise training with a heart device: a hemodynamic, metabolic, and hormonal study.

PURPOSE: The mechanisms of the training-induced improvements in left ventricular assist (LVAD) patients are unknown. METHODS: We measured the hemodynamic, gas exchange, and metabolic and hormonal effects of 6-wk exercise training in a cardiogenic shock patient who was assisted by an LVAD. RESULTS: After training, the peak power and VO2 increased by 166% and 56%, respectively (80 W and 16.1 mL x min(-1) x kg(-1)), whereas the ventilatory drive decreased. Although the LVAD output increased little with exercise, the systemic cardiac output rose (adequately for the VO2) from 5.91 and 4.90 L x min(-1) at rest to 9.75 and 9.47 L x min(-1) at peak work rate, before and after training, respectively. Thus, the left ventricle ejected again through the aortic valve. Unloading and/or retraining resulted in a left ventricular filling pressure decrease. Although the right ventricular ejection fraction increased with exercise, it decreased again at the maximal load after training. For a given work rate the arterial lactate, the norepinephrine (NE) and epinephrine (E) concentrations fell after training, but the enhanced maximal work rate elicited higher NE and E concentrations (4396 and 1848 pg x mL(-1), respectively). The lack of right ventricular unloading might have kept the atrial natriuretic peptide higher after training, but the blood cyclic GMP and endothelin were lower after training. CONCLUSION: In an LVAD patient, retraining returns the exercise capacity to the class III level by peripheral and left ventricular hemodynamic improvements, but the safety of maximal exercise remains to be proven in terms of right ventricular function and orthosympathetic drive.

Granulocytic Ehrlichiae in Ixodes persulcatus ticks from an area in China where Lyme disease is endemic.

A total of 372 adult Ixodes persulcatus ticks were collected from vegetation in a forest area of Heilongjiang Province in northeastern China, where Lyme disease is known to be endemic. The ticks were examined for the presence of granulocytic ehrlichiae by heminested PCR with primers derived from the 16S rRNA gene. Of 310 ticks obtained from the Dahe forestry farm, two pools (each containing 5 ticks) were found positive, with a minimum infection rate of 0.6%. Ehrlichial DNA was also detected in one female (1.6%) of 62 ticks collected from the Yulin forestry farm. The overall minimum infection rate of the 372 I. persulcatus adults was 0.8%. The nucleotide sequences of 919-bp PCR products from the three positive tick specimens were identical to each other and very closely related to the members of the Ehrlichia phagocytophila genogroup. This is the first identification of granulocytic ehrlichiae in ticks in Asia and the first report of infection in I. persulcatus anywhere.

VO(2) kinetics reveal a central limitation at the onset of subthreshold exercise in heart transplant recipients.

Because the cardiocirculatory response of heart transplant recipients (HTR) to exercise is delayed, we hypothesized that their O(2) uptake (VO(2)) kinetics at the onset of subthreshold exercise are slowed because of an impaired early "cardiodynamic" phase 1, rather than an abnormal subsequent "metabolic" phase 2. Thus we compared the VO(2) kinetics in 10 HTR submitted to six identical 10-min square-wave exercises set at 75% (36 +/- 5 W) of the load at their ventilatory threshold (VT) to those of 10 controls (C) similarly exercising at the same absolute (40 W; C40W group) and relative load (67 +/- 14 W; C67W group). Time-averaged heart rate, breath-by-breath VO(2), and O(2) pulse (O(2)p) data yielded monoexponential time constants of the VO(2) (s) and O(2)p increase. Separating phase 1 and 2 data permitted assessment of the phase 1 duration and phase 2 VO(2) time constant (). The VO(2) time constant was higher in HTR (38.4 +/- 7.5) than in C40W (22.9 +/- 9.6; P < or = 0. 002) or C67W (30.8 +/- 8.2; P < or = 0.05), as was the O(2)p time constant, resulting from a lower phase 1 VO(2) increase (287 +/- 59 vs. 349 +/- 66 ml/min; P < or = 0.05), O(2)p increase (2.8 +/- 0.6 vs. 3.6 +/- 1.0 ml/beat; P < or = 0.0001), and a longer phase 1 duration (36.7 +/- 12.3 vs. 26.8 +/- 6.0 s; P < or = 0.05), whereas the was similar in HTR and C (31.4 +/- 9.6 vs. 29.9 +/- 5.6 s; P = 0.85). Thus the HTR have slower subthreshold VO(2) kinetics due to an abnormal phase 1, suggesting that the heart is unable to increase its output abruptly when exercise begins. We expected a faster in HTR because of their prolonged phase 1 duration. Because this was not the case, their muscular metabolism may also be impaired at the onset of subthreshold exercise.

Lung membrane diffusing capacity, heart failure, and heart transplantation.

The pulmonary diffusing capacity for carbon monoxide (DLCO) is reduced in chronic heart failure and remains decreased after heart transplantation. This decrease in DLCO may depend on a permanent alteration after transplantation of one or the other of its components: diffusion of the alveolar capillary membrane or the pulmonary capillary blood volume (Vc). Therefore, we measured DLCO, the membrane conductance, and Vc before and after heart transplantation. At the time of hemodynamic measurements, the Roughton and Forster method of measuring DLCO at varying alveolar oxygen concentrations was used to determine the membrane conductance, Vc, DLCO/alveolar volume (VA), the membrane conductance/VA and thetaVc/VA (theta = carbon monoxide conductance of blood, VA = alveolar volume) in 21 patients with class III to IV heart failure before and after transplantation, and in 21 healthy controls. Transplantation normalized pulmonary capillary pressure and increased cardiac index. DLCO was decreased before transplantation (7.11 vs 10.0 mmol/min/kPa in controls), but DLCO/VA was normal (1.67+/-0.44 vs 1.71+/-0.26 mmol/min/kPa/L in controls). DLCO/VA remained unchanged after transplantation, because the decrease in Vc (82+/-30 vs 65+/-18 ml before and after transplantation) and thetaVc/VA was not compensated by the changes in membrane conductance (11+/-4 vs 12+/-5 mmol/min/kPa before and after transplantation, respectively) and membrane conductance/VA. We conclude that the decrease in DLCO in patients with chronic heart failure is due to a restrictive ventilatory pattern because their DLCO/VA remains normal; the decrease in the membrane conductance is compensated by the increase in Vc. After transplantation, the decrease in Vc due to normalization of pulmonary hemodynamics is not completely compensated for by an increase in membrane conductance. Because the membrane conductances, measured before and after transplantation, are negatively correlated with duration of heart failure, its abnormal pulmonary hemodynamics may have irreversibly altered the alveolar capillary membrane.