Waning Antibody Responses in Asymptomatic and Symptomatic SARS-CoV-2 Infection

We investigated the kinetics of severe acute respiratory syndrome coronavirus 2 neutralizing antibodies in 7 asymptomatic persons and 11 patients with pneumonia. The geometric mean titer of neutralizing antibodies declined from 219.4 at 2 months to 143.7 at 5 months after infection, indicating a waning antibody response.     

天麻的组织培养及快速繁殖

目的：利用组织培养方法快速繁殖成米麻作为种麻,为寻找出一简便可行的快繁天麻种麻的新途径提供理论依据。方法：天麻块茎或茎尖无菌离体培养,米麻块茎诱导培养基为1／2MS＋6－BA 1mg/L NAA0.5mg/L＋香蕉50mg/L;箭麻茎尖诱导培养基为1／2MS＋6－BA2mg/L NAAO.2mg/L。结果：小米麻经50d无菌培养后开始生长出新米麻,70d后原小米麻块茎上生长出多个分枝的新米麻;箭麻茎尖超过140d组织培养,茎尖分化、诱导形成原球茎,超过160d培养原球长大并开花。结论：天麻可以用组织培养方法快速繁殖成米麻作为种麻。     

Atlantoaxial instability in a patient with neck pain and rheumatoid arthritis

Context: The purpose of this report is to describe the clinical decision-making process for a patient with rheumatoid arthritis with neck pain with underlying atlantoaxial instability.Findings: The patient was evaluated for worsening upper neck pain that began insidiously 1 year prior. The patient denied numbness or tingling in her upper or lower extremities, dizziness or lightheadedness, difficulty maintaining balance with walking, or muscle weakness. Cervical spine range of motion was limited in all planes due to pain and apprehension. The patient’s neurological examination was unremarkable. Prior flexion and extension radiographs of the cervical spine were interpreted as unremarkable with alignment preserved in flexion and extension. However, upon further inspection, the cervical spine flexion radiograph was concerning for inadequate cervical motion, which may have limited the diagnostic utility of these radiographs. Additionally, a Sharp-Purser test was performed, which was positive for excessive motion. Flexion and extension radiographs of the cervical spine were then repeated ensuring the patient adequately flexed and extended during the imaging. Severe anterior subluxation of C1 relative to C2 with cervical flexion was noted, as C1 moved as much as 8–9 mm anterior to C2 with cervical flexion. Given the degree of atlantoaxial instability, the patient subsequently underwent successful posterior fusion from the occiput to C2.Conclusion/Clinical Relevance: This case report demonstrates the importance of properly screening for upper cervical spine instability in patients with rheumatoid arthritis and neck pain and understanding the importance of obtaining adequate and appropriate diagnostic imaging.     

Biomechanical assessment with electromyography of post-stroke ankle plantar flexor spasticity

Spasticity has been defined as a motor disorder characterized by a velocity-dependent increase in tonic stretch reflex (muscle tone). Muscle tone consists of mechanical-elastic characteristics, reflex muscle contraction and other elements. The aims of this study were to determine whether to assess spasticity quantitatively, and to characterize biomechanical and electromyographic spasticity assessment parameters. These assessment parameters were described by investigating the correlation between clinical measures and the response to passive sinusoidal movement with consecutive velocity increments. Twenty post-stroke hemiplegic patients and twenty normal healthy volunteers were included in the study. Five consecutive sinusoidal passive movements of the ankle were performed at specific velocities (60, 120, 180, and 240 degrees/ sec). We recorded the peak torque, work, and threshold angle using a computerized isokinetic dynamometer, and simultaneously measured the rectified integrated electromyographic activity. We compared these parameters both between groups and between different velocities. The peak torque, threshold angle, work, and rectified integrated electromyographic activity were significantly higher in the post-stroke spastic group at all angular velocities than in the normal control group. The threshold angle and integrated electromyographic activity increased significantly and linearly as angular velocity increased, but the peak torque and work were not increased in the post-stroke spastic group. Peak torque, work, and threshold angle were significantly correlated to the Modified Ashworth scale, but the integrated electromyographic activity was not. The biomechanical and electromyographic approach may be useful to quantitatively assess spasticity. However, it may also be very important to consider the different characteristics of each biomechanical parameter.     

A case of leukemia-associated arthritis--identification of leukemic cells in synovial fluid by light microscopy

One case of arthritis complicating leukemia is described in which leukemic cells were identified in synovial fluid by light microscopy. Although arthritis is a well-known manifestation of leukemia with an incidence of 13.5%, the pathogenesis often is unclear, and the direct demonstration of leukemic cells in synovial fluid has been very uncommon. A 16 year-old male patient was admitted due to left elbow joint pain and swelling. Synovial fluid examination revealed blast cells and this finding has directed to a final diagnosis of acute lymphoblastic leukemia.     

Neonatal effects of adding epidural fentanyl to 0.5% bupivacaine for caesarean section

Epidural injection of opioids has been introduced to improve analgesia during labour and caesarean section. This study was designed to quantify placental transfer of fentanyl and to evaluate neonatal effects of adding fentanyl to 0.5% bupivacaine for epidural anaesthesia in women undergoing elective caesarean section at term. The parturients were randomly allocated to one of four groups of 20, who received either saline (control) or 50, 75 or 100 microg of fentanyl added to 20 ml of 0.5% bupivacaine. Apgar scores, time to sustained respiration and umbilical acid-base values did not differ among the groups. The median (interquartile range) umbilical artery to maternal vein fentanyl concentration ratio was 0.34 (0.26-0.48) when the fentanyl groups were taken together. Neurologic and adaptive capacity scores were evaluated at 2 and 24 h. Neonates whose mothers received fentanyl had lower scores with regard to supporting reaction at 2 h and active tone at 24 h, when compared to controls (P<0.05), but there were no differences among the groups with regard to the other test criteria in the neurobehavioural test. In conclusion, epidural injection of fentanyl 50-100 microg did not produce depression of the term neonate.     

Effect of hepatic cirrhosis on the pharmacokinetics of theophylline in rats

The experimental hepatic cirrhosis was induced either by bile duct ligation (BDL) or by pretreatment with dimethylnitrosamine (DMNA). The pharmacokinetics of theophylline were studied after a single intravenous or a single oral administration. Using the ultrafiltration method, protein-drug binding experiments were also carried out. The bilirubin level was several-fold increased by BDL, but not by DMNA treatment. The albumin content was decreased in both cirrhotic groups. The total clearance (Clt, ml/kg/hr) of theophylline in both hepatic cirrhosis groups significantly decreased and the terminal half-life (t_1/2) in the cirrhotic rats was increased about two-fold after intravenous and oral administration. The volume of distribution at steady state (Vdss, ml/kg) was increased slightly in the cirrhotic groups. Protein binding in BDL (8.67±4.85%) decreased about four-folds, but in DMNA (73.00±9.85%) similar result, was observed as compared with the control. Increased free fraction of theophylline did not increase the volume of distribution in BDL. Therefore decreased total body clearance of theophylline was mainly due to decreased intrinsic clearance of theophylline in the liver. The absolute bioavailability of theophylline in these experiments was between 63.8 and 72.8%(66.1% in BDL, 63.8% in Sham operated and Control, 72.8% in DMNA). These results suggest that in the experimental hepatic cirrhosis model, administration route does not affect the disposition of theophylline.     

Recent trends of age-specific pneumoconiosis mortality rates in the United States, 1985-1996: coal workers' pneumoconiosis, asbestosis, and silicosis

The authors examined the temporal trends of age-specific pneumoconiosis mortality from coal worker's pneumoconiosis (CWP), asbestosis, and silicosis in the United States in 1985-1996. Mortality data were derived from the National Center for Health Statistics multiple causes of death files for the period. Age-specific mortality rates were computed for three age groups (15-44, 45-64, and > or = 65 years) among decedents with mention of CWP, asbestosis, or silicosis. Linear regression analysis was performed to examine the annual changes in age-specific mortality rates, by age group, with each specific condition. The CWP mortality rates declined significantly (p = 0.0001) in the groups 45 years old and older, but not in the age group 15-44. Asbestosis mortality rates declined significantly (p = 0.005) for the age group 45-64, while increasing (p = 0.0001) for those aged 65 years and older. However, in the younger age group 15-44, the rates showed no significant trend. Silicosis mortality rates declined significantly (p = 0.0001) for all groups. The continued occurrence of deaths from CWP, asbestosis, and silicosis among young adults may be the result of high levels of exposure to occupational risks. These results suggest that pneumoconiosis surveillance may help to evaluate the temporal pneumoconiosis mortality patterns in the United States.