提高稀释液浓度测定硫酸卡那霉素含量

目的：探讨按中国药典（2000年版）抗生素微生物检定法测定硫酸卡那霉素含量的最后稀释液浓度范围；方法：应用ZY－300IV型抗生素抑菌圈面积测量分析仪，测定硫酸卡那霉素抑菌圈面积与对数剂量的线性关系范围；结果：测定硫酸卡那霉素含量时，最后稀释液浓度范围在5.5-20.4IU/ml内对数剂量与抑菌圈面积呈直线关系。     

Assessment of patellar maltracking using combined static and dynamic MRI

Between January 1995 and Jul 1997, 474 patients with anterior knee pain resistant to conservative treatment were referred for MR of the knee. The MR examination consisted of routine sequences with an additional patellofemoral dynamic examination using a technique that has been developed at this institution. The dynamic study examines both knees simultaneously, with the patient supine and the quadriceps loaded. No gating or restraint apparatus is needed. Patellar subluxation or tilt was present in 188(40 %) of cases, bilateral in 104 and unilateral in 84 cases (right 39, left 45). It was classified as mild in 51 %, moderate in 39 % and severe in 10 %. Subluxation was more prevalent in females than males (42 % vs. 37 %) and this was most obvious in the severe group where 68 % were female. In 90 knees selected at random, four measurements of patellofemoral morphology were obtained using reconstructed images from a volume gradient echo sequence. These measurements were correlated with the degree of subluxation or tilt. A tibial tubercle distance greater than 20 mm, a femoral sulcus angle greater than 150 degrees, sulcus depth less than 4 mm were specific for subluxation but no measurement proved to be sufficiently sensitive to preclude a tracking study. MRI can be used to define more precisely the anatomy of the extensor mechanism and its relationship to the femur and tibia, in both a static and dynamic setting. In this way, patients with anterior knee pain can be classified more accurately and the outcomes of treatment more reliably assessed. Received: 17 September 1999; Revised: 31 January 2000; Accepted: 4 February 2000     

豚鼠血液流变学指标正常参考范围的研究

目的建立豚鼠血液流变学各指标的正常参考范围,供学者及同行作研究或实验时参考。方法用心脏采血法采集豚鼠血液5ml、肝素抗凝,雄性44只、雌性23只;用MVIS-2020全自动血液流变学分析仪检测豚鼠血液流变学各指标。结果豚鼠全血黏度(高切)正常值:雄性(5.17±0.72)mpas,雌性(4.86±0.69)mpas;全血黏度(低切):雄性(10.37±1.59)mpas,雌性(9.34±1.38)mpas;血浆黏度:雄性(1.42±0.15)mpas,雌性(1.40±0.13)mpas;全血还原黏度:雄性(6.28±0.90)mpas,雌性(5.93±0.88)mpas;红细胞压积:雄性0.42±0.03,雌性0.37±0.02。结论动物种系之间血液流变学指标存在差异;豚鼠血液流变学结果与性别有关。     

计算机编程建立肝脏移植患者他克莫司的有效血药浓度范围

目的 :为临床合理化使用免疫抑制剂他克莫司 (FK5 0 6 )提供理论依据 ,建立适合中国人肝脏移植受者FK5 0 6的有效血药浓度范围。方法 :用VISUALBASIC 6 .0开发程序 ;程序对用微粒子酶免分析法 (MEIA)测定全血FK5 0 6的血药浓度数据进行处理。结果 :肝脏移植术后 1mo内FK5 0 6理想有效血药浓度范围为 7～ 14 μg·L-1。结论 :该程序是开展治疗药物监测工作非常实用的工具 ,按程序所推荐浓度范围调整给药方案 ,既可获得满意的免疫抑制效果 ,又能减少排斥反应和FK5 0 6毒性     

HOW TO ASSESS THE RELATIVE RANGE OF TWO CONSECUTIVE LABORATORY MEASUREMENTS TO MONITOR PATIENTS

An integral part of routine health checkups involves laboratory measurements on various analytes in the blood. It is then common to compare the value of two consecutive measurements sampled at different times from the same patient. A “significant” change requires an action (additional sample and/or clinical action). The current rule is to check whether the relative range of measurement is larger than a certain critical threshold. This rule should guarantee a specified confidence level (e.g., 95%), but its derivation was based on an approximation. We derive the exact distribution and show that it is related to the doubly noncentral F distribution. The currently used threshold values are compared with the exact ones, and some limited power calculations are presented to detect changes in the patient condition.     

Inequalities in enrollment of women and racial minorities in trials testing uric acid lowering drugs

AimsWe investigated sex and racial inequalities in clinical trials testing serum uric acid (SUA) lowering drugs and analyzed the temporal trends of participation among the pre-specified demographic groups.Data were collected from publications of clinical trials testing SUA-lowering drugs. Linear regression analysis was performed to assess the relation between drug approval year and proportion of women and minorities enrolled in clinical studies.Data synthesisThe mean percentage enrollment of women in clinical trials significantly decreased over the time (r = −0.43, P-value = 0.02). Moreover, there was a statistically significant difference in mean percentage enrollment of women among trials testing different SUA-lowering drugs, with the highest representation in rasburicase (71.1%) and the lowest representation of women in dotinurad (0.8%). Over the time, also the mean percentage enrollment of racial minorities decreased, passing from 8.7% to 2.2% in a 10-year period.Women were proportionally underrepresented compared with their share of the population with asymptomatic hyperuricemia, overall (participation-to-prevalence ratio (PPR) = 0.34), in trials testing xanthine oxiase inhibitors (PPR = 0.38) and uricosurics (PPR = 0.29), and in trials with febuxostat, allopurinol, pegloticase, halofenate/arhalofenate, verinurad, lesinurad and dotinurad. Women were proportionally underreppresented also compared with their share of the population with gout, overall (PPR = 0.69) and in trials testing XOIs (PPR = 0.69), uricosurics (PPR = 0.68), and all SUA-lowering drugs excepted for rasburicase, pegloticase and topiroxostat.ConclusionsOur analysis shows that women and racial and ethnical minorities are underrepresented in controlled clinical trials testing SUA-lowering drugs, with similar pattern across drug classes.     

Place and Time Coding of Frequency in the Peripheral Auditory System: Some Physiological Pros and Cons

Evidence for and against classical theories of ‘place’ and ‘period’ mechanisms for the coding of frequency, and the modifications of the theories invoked to account for the pitch of ‘residue’ and other types of stimuli, are examined in the light of physiological data. These include new data on the temporal discharge patterns of cochlear nerve fibres under stimulation with two-tone complexes, harmonic and inharmonic three-tone complexes, and five-tone complexes of differing relative phase. They show, in particular, that certain arguments against ‘period’ coding of ‘residue’ pitch are invalid. The interspike intervals in the discharge patterns of cochlear fibres under these conditions are consistent with the pitches heard. On the other hand, the classical ‘period’ theory needs to be modified to take into account the normally relatively sharp frequency selectivity of cochlear fibres, and requires certain inefficiencies on the part of the central processor for pitch.

Comparison of measures of cochlear fibre frequency selectivity with analogous psychophysical data in man, including those on the ‘existence region’ of ‘residue’ pitch, suggests that ‘residue’-type stimuli judged to be tonal in quality could both: (a) be sufficiently resolved spectrally at the cochlear fibre level to serve as input to any of the current spectral ‘pattern recognition’ mechanisms proposed for the pitch extraction of complex signals, and also, (b) could generate patterns of temporal discharge reflecting enough waveform interaction between the harmonics to convey the pitch heard, because of the shape of the cochlear filters. (This conclusion might have to be qualified in the light of further physiological experiments on the ‘second effect’ of pitch shift.)

The present evidence, both psychophysical and physiological, suggests the following synthesis: musical interval recognition and relatively crude frequency discrimination can be accomplished by trained observers on signals where the frequency appears to be coded exclusively in terms of temporal information. However, the pitch quality of these signals is judged to be poor or absent. Likewise, signals, apparently coded exclusively by ‘place’ mechanisms, while having tonality, allow relatively crude frequency discrimination and judgment of musical intervals. With the possible exception of psychophysical data on the phenomenon of diplacusis, the present evidence cannot exclude the possibility that the central pitch extractor mechanism utilizes both the ‘place’ and ‘period’ cues produced by pure-tone signals (below 5 kHz) and ‘residue’-type signals, both signals evoking strong pitch and fine acuity of frequency discrimination. The degree of salience of a signal's pitch could well depend on the coherence of the two types of cue.

However, the greatest obstacle to the acceptance of ‘place’ coding mechanisms for frequency, particularly of the frequency components of a complex sound, is the restricted dynamic range of the peripheral elements of the auditory nervous system. Because of this, it is not clear how differences in the spectral energy distribution in signals at medium to high sound levels can be established in terms of patterns of mean discharge rate across the cochlear fibre array. At high sound levels, physiological evidence suggests that the discharge rates of the majority of stimulated fibres will be saturated, whereas psychophysical evidence suggests that the coding of the frequency and the relative level of even single-component signals can be carried out over a wide dynamic range in the absence of cues derived from spread of activity across the fibre array. Some new data, however, indicate that this problem may be circumvented at the cochlear nucleus level, but the coding mechanisms involved at the primary neurone level are obscure. One intriguing possibility exists that the auditory nervous system may utilize the fine temporal structure of cochlear fibre discharge patterns for the transmission of ‘place’ information.     

Outcomes of Carotid Revascularization in Patients with Contralateral Carotid Artery Occlusion

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Impact of Margin Status on Survival in Patients with Pancreatic Ductal Adenocarcinoma Receiving Neoadjuvant Chemotherapy

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Lack of effectiveness of 13-valent pneumococcal conjugate vaccination against pneumococcal carriage density in Papua New Guinean infants

BackgroundPapua New Guinea (PNG) introduced the 13-valent pneumococcal conjugate vaccine (PCV13) in 2014, with administration at 1, 2, and 3 months of age. PCV13 has reduced or eliminated carriage of vaccine types in populations with low pneumococcal carriage prevalence, carriage density and serotype diversity. This study investigated PCV13 impact on serotype-specific pneumococcal carriage prevalence, density, and serotype diversity in PNG infants, who have some of the highest reported rates of pneumococcal carriage and disease in the world.MethodsNasopharyngeal swabs were collected at 1, 4 and 9 months of age from PCV13-vaccinated infants (n = 57) and age-/season-matched, unvaccinated infants (at approximately 1 month, n = 53; 4 months, n = 57; 9 months, n = 52). Serotype-specific pneumococcal carriage density and antimicrobial resistance genes were identified by qPCR and microarray.ResultsPneumococci were present in 89% of swabs, with 60 different serotypes and four non-encapsulated variants detected. Multiple serotype carriage was common (47% of swabs). Vaccine type carriage prevalence was similar between PCV13-vaccinated and unvaccinated infants at 4 and 9 months of age. The prevalence of non-vaccine type carriage was also similar between cohorts, with non-vaccine types present in three-quarters of samples (from both vaccinated and unvaccinated infants) by 4 months of age. The median pneumococcal carriage density was high and similar at each age group (~7.0 log₁₀ genome equivalents/mL). PCV13 had no effect on overall pneumococcal carriage density, vaccine type density, non-vaccine type density, or the prevalence of antimicrobial resistance genes.ConclusionPNG infants experience dense and diverse pneumococcal colonisation with concurrent serotypes from 1 month of age. PCV13 had no impact on pneumococcal carriage density, even for vaccine serotypes. The low prevalence of vaccine serotypes, high pneumococcal carriage density and abundance of non-vaccine serotypes likely contribute to the lack of PCV13 impact on carriage in PNG infants. Indirect effects of the infant PCV programs are likely to be limited in PNG. Alternative vaccines with broader coverage should be considered.