Prenatal diagnosis and appearance of nasal chondromesenchymal hamartoma in a fetus: A case report

We report a case of fetal nasal chondromesenchymal hamartoma (NCMH) first noted on prenatal ultrasound at 34 weeks. A solid-cystic mass which predominantly hyperechoicgenic and relatively clear margin, was located on the left nasal cavity and pharynx, with anterior extension and moderate blood flow. Further follow-up ultrasound examination depicted an enlargement of the tumor. Fetal magnetic resonance imaging (MRI) showed an inhomogeneous signal lesion involving the ethmoid sinuses, nasal cavity, and pharynx. The infant, delivered via cesarean section at 37 + 5 weeks, required urgent neonatology intervention due to respiratory difficulties. Neonatal MRI and computer tomography were subsequently performed at 1 day after birth. Surgical excision occurred at 7 days, confirming NCMH via histological examination. Awareness of this entity, is essential to avoid potentially harmful therapies, especially in prenatal period. Considered NCMH in diagnosis when fetal nasal masses presenting with predominantly high-level echo, well-defined margins and moderate vascularity.

A systematic analysis on global epidemiology and burden of foot fracture over three decades

PURPOSE

To comprehensively analyze the geographic and temporal trends of foot fracture, understand its health burden by age, sex, and sociodemographic index (SDI), and explore its leading causes from 1990 to 2019.

METHODS

The datasets in the present study were generated from the Global Burden of Diseases Study 2019, which included foot fracture data from 1990 to 2019. We extracted estimates along with the 95% uncertainty interval (UI) for the incidence and years lived with disability (YLDs) of foot fracture by location, age, gender, and cause. The epidemiology and burden of foot fracture at the global, regional, and national level was exhibited. Next, we presented the age and sex patterns of foot fracture. The leading cause of foot fracture was another focus of this study from the viewpoint of age, sex, and location. Then, Pearson's correlations between age-standardized rate (ASR), SDI, and estimated annual percentage change were calculated.

RESULTS

The age-standardized incidence rate was 138.68 (95% UI: 104.88 - 182.53) per 100,000 persons for both sexes, 174.24 (95% UI: 134.35 - 222.49) per 100,000 persons for males, and 102.19 (95% UI: 73.28 - 138.00) per 100,000 persons for females in 2019. The age-standardized YLDs rate was 5.91 (95% UI: 3.58 - 9.25) per 100,000 persons for both genders, 7.35 (95% UI: 4.45 - 11.50) per 100,000 persons for males, and 4.51 (95% UI: 2.75 - 7.03) per 100,000 persons for females in 2019. The global incidence and YLDs of foot fracture increased in number and decreased in ASR from 1990 to 2019. The global geographical distribution of foot fracture is uneven. The incidence rate for males peaked at the age group of 20 - 24 years, while that for females increased with advancing age. The incidence rate of older people was rising, as younger age incidence rate declined from 1990 to 2019. Falls, exposure to mechanical forces, and road traffic injuries were the 3 leading causes of foot fracture. Correlations were observed between ASR, estimated annual percentage change, and SDI.

CONCLUSIONS

The burden of foot fracture remains high globally, and it poses an enormous public health challenge, with population ageing. It is necessary to allocate more resources to the high-risk populations. Targeted realistic intervention policies and strategies are warranted.

[Analysis of conventional echocardiographic features in apical hypertrophic cardiomyopathy patients complicated with left ventricular apical aneurysm]

Objective: To explore the basic characteristics of conventional echocardiography of apical hypertrophic cardiomyopathy (ApHCM) patients complicating with left ventricular apical aneurysm (LVAA). Methods: This is a retrospective study. Patients who underwent echocardiography and cardiac magnetic resonance (CMR) and were diagnosed with ApHCM complicated with LVAA by CMR at Fuwai Hospital, Chinese Academy of Medical Sciences from August 2012 to July 2017 were enrolled. According to whether LVAA was detected by echocardiography, the enrolled patients were divided into two groups: LVAA detected by echocardiography group and LVAA not detected by echocardiography group. Clinical data of the two groups were compared to analyze the causes of missed diagnosis by echocardiography. Results: A total of 21 patients were included, of whom 67.0% (14/21) were males, aged (56.1±16.5) years. Patients with chest discomfort accounted for 81.0% (17/21), palpitation 38.1% (8/21), syncope 14.3% (3/21). ECG showed that 21 (100%) patients had ST-T changes and 18 (85.7%) had deep T-wave invertion. Echocardiography revealed ApHCM in 17 cases (81.0%) and LVAA in 7 cases (33.3%). The mean left ventricular apical aneurysm diameter was 33.0 (18.0, 37.0) mm, and left ventricular ejection fraction was (66.5±6.6) %, and left ventricular apex thickness was (21.0±6.3) mm. Left ventricular outflow tract obstruction was presented in 4 cases and middle left ventricular obstruction in 10 cases. The mean left ventricular apical aneurysm diameter of LVAA detected by echocardiography was greater than that of LVAA not detected by echocardiography (25.0 (18.0, 28.0) mm vs. 16.0 (12.3, 21.0) mm, P=0.006). Conclusions: Conventional echocardiography examination has certain limitations in the diagnosis of ApHCM. Smaller LVAA complicated with ApHCM is likely to be unrecognized by echocardiography. Clinicians should improve their understanding of this disease.

The Ratio of Clavicle Length to Head Circumference: A Novel Date-Independent Clavicle Index

ABSTRACT

We aimed to plot the growth curve of the fetal clavicle, identify gestational date-independent parameters. Using 2-dimensional ultrasonography, we obtained the clavicle lengths (CLs) from 601 normal fetuses between 12 and 40 gestational age (GA). The CL/fetal growth parameters ratio was calculated. Moreover, 27 cases of fetal growth restriction (FGR) and 9 cases of small for GA (SGA) were detected. In normal fetuses, the mean CL (mm) = -68.2 + 29.80 × ln(GA) ± Z × (1.07 + 0.02 × GA). A linear relationship was detected between CL and head circumference (HC), biparietal diameter, abdominal circumference and femoral length with R2 values of 0.973, 0.970, 0.962, and 0.972, respectively. The CL/HC ratio (mean value 0.130) showed no significant correlation with GA. Clavicle lengths in the FGR group significantly decreased compared with the SGA group ( P < 0.01). This study determined a reference range of fetal CL in a Chinese population. Furthermore, the CL/HC ratio, which is independent of GA, is a novel parameter for the evaluation of the fetal clavicle.

Exosomes derived from inflammatory myoblasts promote M1 polarization and break the balance of myoblast proliferation/differentiation

BACKGROUND

Acute muscle injuries are one of the most common injuries in sports. Severely injured muscles are prone to re-injury due to fibrotic scar formation caused by prolonged inflammation. How to regulate inflammation and suppress fibrosis is the focus of promoting muscle healing. Recent studies have found that myoblasts and macrophages play important roles in the inflammatory phase following muscle injury; however, the crosstalk between these two types of cells in the inflammatory environment, particularly the exosome-related mechanisms, had not been well studied.

AIM

To evaluate the effects of exosomes from inflammatory C2C12 myoblasts (IF-C2C12-Exos) on macrophage polarization and myoblast proliferation/differentiation.

METHODS

A model of inflammation was established in vitro by lipopolysaccharide stimulation of myoblasts. C2C12-Exos were isolated and purified from the supernatant of myoblasts by gradient centrifugation. Multiple methods were used to identify the exosomes. Gradient concentrations of IF-C2C12-Exos were added to normal macrophages and myoblasts. PKH67 fluorescence tracing was used to identify the interaction between exosomes and cells. Microscopic morphology, Giemsa stain, and immunofluorescence were carried out for histological analysis. Additionally, ELISA assays, flow cytometry, and western blot were conducted to analyze molecular changes. Moreover, myogenic proliferation was assessed by the BrdU test, scratch assay, and CCK-8 assay.

RESULTS

We found that the PKH-67-marked C2C12-Exos can be endocytosed by both macrophages and myoblasts. IF-C2C12-Exos induced M1 macrophage polarization and suppressed the M2 phenotype in vitro. In addition, these exosomes also stimulated the inflammatory reactions of macrophages. Furthermore, we demonstrated that IF-C2C12-Exos disrupted the balance of myoblast proliferation/differentiation, leading to enhanced proliferation and suppressed fibrogenic/myogenic differentiation.

CONCLUSION

IF-C2C12-Exos can induce M1 polarization, resulting in a sustained and aggravated inflammatory environment that impairs myoblast differentiation, and leads to enhanced myogenic proliferation. These results demonstrate why prolonged inflammation occurs after acute muscle injury and provide a new target for the regulation of muscle regeneration.

Urokinase plasminogen activator predicts poor prognosis in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and its prognosis remains dismal. Hence, it is important to identify the diagnostic and prognostic biomarkers for HCC. Urokinase plasminogen activator (uPA), an extracellular matrix (ECM)-degrading protease, plays a pivotal role in the invasion and metastasis of HCC.

Methods

To confirm the clinical significance of uPA in HCC, we explored uPA expression in HCC in The Cancer Genome Atlas (TCGA) database. The expression level of uPA was further verified by quantitative reverse transcription polymerized chain reaction (qRT-PCR) in 133 pairs of primary HCC samples. A survival analysis was conducted with the Kaplan-Meier method in the HCC samples and TCGA database.

Results

Our results showed that uPA was overexpressed in HCC and was significantly associated with HCC tumor size (P=0.015), differentiation grade (P=0.028), and absence of tumor encapsulation (P=0.010). Patients with high uPA expression levels had a poor outcome (P=0.026). TCGA database analysis was also consistent with our experimental results.

Conclusions

In conclusion, our findings revealed that uPA was overexpressed in HCC and was related to HCC malignant features including tumor size, differentiation grade and absence of tumor encapsulation. High uPA expression had a shorter survival time. It is a potential prognostic biomarker of HCC.

SERPINA11 Inhibits Metastasis in Hepatocellular Carcinoma by Suppressing MEK/ERK Signaling Pathway

Purpose

By using integrative RNA sequencing analysis, we identified a novel tumor suppressor, serpin family A member 11 (SERPINA11), which is a serine proteinase inhibitor that belongs to the serpin superfamily. However, the function of SERPINA11 in hepatocellular carcinoma (HCC) remains unclear. The aim of this study was to investigate the role and molecular mechanism of SERPINA11 in HCC.

Methods

Gene expression patterns of SERPINA11 were analyzed in tissue samples of HCC patients by qRT-PCR. In vitro and in vivo experiments were performed to characterize the function and molecular mechanism of SERPINA11 in the tumor metastasis capacity.

Results

SERPINA11 was downregulated in approximately 50% of HCC and significantly associated with metastasis and poor outcome of patients. Functional study demonstrated that SERPINA11 could inhibit cell growth, cell migration and tumor metastasis. Mechanistic investigations suggested that SERPINA11 accelerated urokinase-type plasminogen activator (uPA) degradation to suppress extracellular signal-regulated kinase (ERK1/2) phosphorylation, and thereby subdued metastatic capabilities of HCC cells.

Conclusion

SERPINA11 plays an important tumor suppressive role in HCC, with possible use as a biomarker and an intervention point for new therapeutic strategies.

Case report and literature review: antenatal diagnosis of a fetal anaplastic astrocytoma

OBJECTIVES

To describe the ultrasonographic appearance of congenital anaplastic astrocytoma, so as to provide diagnostic clues for it. An updated review of the literature was also carried out.

RESULTS

There was a case of fetal anaplastic astrocytoma detected by ultrasound at 37 + 1 weeks of gestation. It showed that a hypoechoic mass was located in the left hemisphere with a relatively clear margin and subtle color flows. Prenatal magnetic resonance imaging (MRI) which was taken subsequently confirmed the result of ultrasound. Intratumoral hemorrhage was observed in later follow-up and further confirmed by histological examination. The fetus was delivered vaginally at 39 + 6 weeks. The infant died 2 h after delivery due to respiration failure. The histological examination confirmed an anaplastic astrocytoma.

CONCLUSIONS

Congenital anaplastic astrocytoma commonly detected by ultrasound has a relatively better perinatal prognosis, especially compared with glioblastoma. Prenatal ultrasonography diagnosis accurately is of critical importance. The anaplastic astrocytoma should be considered in cases in which fetal images reveal a heterogeneous echogenic mass in the brain, especially in the presence of intratumoral hemorrhage, subtle color flow, and relatively clear margin.

[A 5-year follow-up study of pneumoconiosis patients with positive autoantibody]

Objective: To explore the progress of small shadow and the change of lung function in pneumoconiosis with positive autoantibody, so as to provide basis for clinical treatment of pneumoconiosis. Methods: A total of 756 patients were admitted to the pneumoconiosis department of the Guangzhou Occupational Disease Prevention Hospital from January 1, 2013 to June 1, 2019. The patients with combined infection were excluded. According to whether the autoantibody was positive, they were divided into positive group and negative group, 25 cases in each group. Follow-up observation of X-ray chest radiographs, chest CT, forced expiratory volume in one second (FEV(1)) and forced expired flow at 50% of FVC (MEF(50)) of pneumoconiosis patients for 5 years, to analyze the influence of positive autoantibody on the morphology of X-ray chest film, the pneumoconiosis promotion in 5 years and lung function. Results: There were 22 males and 3 females in the autoantibody positive group, aged 53.14±10.51 years. In the autoantibody negative group, there were 23 males and 2 females, aged 53.88±8.10 years. During the 5-year observation period, there was no significant difference of small shadow shape, pneumoconiosis stage, and the pneumoconiosis promotion in 5 years between the autoantibody positive group and the autoantibody negative group (P>0.05). However, the increment of small shadow area in the autoantibody positive group was higher than that in the autoantibody negative group (P<0.05). FEV(1) and MEF(50) of the autoantibody positive group were significantly lower than those of the autoantibody negative group in the fourth and third years, respectively (P<0.05). Positive autoantibody was negatively correlated with FEV(1) and MEF(50) (P<0.05). Conclusion: The positive autoantibody can't promote the progress of X-ray, but show more small shadows on chest CT; the positive autoantibody may aggravate the decline of lung function.

[Influencing factors of postoperative acute kidney injury in patients undergoing cardiac surgery]

Objective: To analyze the influencing factors of acute kidney injury (AKI) in patients after cardiac surgery using levosimendan or dobutamine, and explore the effect of positive inotropic drugs on AKI. Methods: The clinical data of 417 patients undergoing cardiac surgery from January to June 2018 in Beijing Anzhen Hospital and treated with levosimendan or dobutamine during perioperative period were retrospectively reviewed and collected. Patients were divided into AKI group and non-AKI group according to whether AKI occurred. Univariate logistic regression analysis was used to analyze the factors related to the occurrence of AKI. The statistically significant factors (P<0.05) were further included in the multivariate logistic regression analysis. Results: Totally, 417 patients were enrolled in the study, with a mean age of (58.2±10.4) years old and a male rate of 65.0% (n=271), and the AKI incidence rate was 25.2% (105/417). Univariate logistic regression analysis showed that male, chronic kidney disease, high serum creatinine level in preoperative period, aortic obstruction time ≥ 120 minutes and extracorporeal circulation time ≥ 120 minutes were risk factors for AKI (all P<0.05). Vasodilator and levosimendan treatment during perioperative period were protective factors (P<0.05). Multivariate logistic regression analysis showed that chronic kidney disease (OR=17.291, 95%CI: 4.335-68.960, P<0.001) and high serum creatinine level (OR=1.097, 95%CI: 1.074-1.121, P<0.001) in preoperative period were independent risk factors for AKI. Perioperative application of levosimendan (OR=0.533, 95%CI: 0.288-0.984, P=0.044) was an independent protective factor. Conclusions: Risk factors for AKI after cardiac surgery include chronic kidney disease and high serum creatinine level in preoperative period. The use of levosimendan during preoperative period has the potential effect to protect against AKI.

Integrative genomic analyses identify WDR12 as a novel oncogene involved in glioblastoma

Glioblastoma (GBM) is the most malignant primary brain tumor in adults. Due to its invasive nature, it cannot be thoroughly eliminated. WD repeat domain 12 (WDR12) processes the 32S precursor rRNA but cannot affect the synthesis of the 45S/47S primary transcript. In this study, we found that WDR12 is highly expressed in GBM according to the analysis results of mRNA expression by The Cancer Genome Atlas database. The high expression level of WDR12 is dramatically related to shorter overall survival and reduced disease-free survival. Next, we knocked down WDR12 and found that knockdown of WDR12 promoted the apoptosis and inhibited the proliferation by cell biology experiments. Differential expression genes in gene-chip revealed that WDR12 knockdown mainly inhibited cell cycle. Finally, we also found that WDR12 is associated with PLK1 and EZH2 in cell proliferation of GBM. Resumptively, this report showed a possible evidence that WDR12 drove malignant behavior of GBM, whose expression may present a neoteric independent prognostic biomarker in GBM.

Prenatal Evaluation for Detection of Anorectal Atresia: Value of Ultrasound

OBJECTIVES

To investigate the applicability and value of ultrasound (US) in the diagnosis of anorectal atresia.

METHODS

Between January 2008 and January 2016, we prospectively evaluated 63,101 fetuses (gestational age, 20-38 weeks), including low- and high-risk populations using 2-dimensional US scans. An abnormal imaging finding was defined as an anal canal diameter of less than the 95% confidence interval (small anal canal) of the normal range or the absence of an anal canal and rectum. Imaging findings were considered normal on detection of an anal canal with a normal width and the absence of abnormalities. Prenatal imaging findings were confirmed by a postnatal or postmortem examination.

RESULTS

Among the investigated fetuses, 28 showed evidence of anorectal atresia on US scans, and 22 of those with anorectal atresia had additional anomalies. Six cases of isolated anorectal atresia were successfully detected during the preclusive prenatal US scans. Four cases of a low imperforate anus (including 2 covered anuses) yielded false-negative results, indicating a diagnostic rate of 87.5% (28 of 32). The normal appearance of the fetal rectum and anal canal ruled out anorectal atresia in 30 fetuses with a dilated colon. Additionally, there were 3 false-positive cases, in which a narrow anal canal was observed.

CONCLUSIONS

Identifying the abnormal appearance or absence of the fetal anal canal and rectum on preclusive US anomaly scans is useful for prenatal diagnosis or exclusion of anorectal atresia, which may help improve the detection of isolated anorectal atresia. Furthermore, a combined evaluation of the longitudinal and axial appearances of the fetal anal canal and rectum can improve diagnostic accuracy.

Parasitism Performance of Tetrastichus brontispae Ferriere over the Coconut Hispine Beetle, Brontispa longissima (Gestro)

In this study, the effect of host density, host, and parasitoid ages in choice and no-choice tests on the parasitism performance of Tetrastichus brontispae Ferriere, one of the major parasitoid of Brontispa longissima (Gestro), was investigated in the laboratory. The results revealed that an increased host density resulted in no increased parasitism of B. longissima by T. brontispae; the optimal host density was three host pupae per parasitoid when considering the costs for mass rearing. Moreover, parasitoid age was quite crucial for effective parasitism and affected the emergence rate. Although 2-h to 4-day-old parasitoids successfully parasitized the host pupae, younger parasitoids (within 2-day-old) presented higher parasitism capacity than older parasitoids. More importantly, both choice and no-choice tests confirmed that all host stages tested from 2-h to 4-day-old were suitable for T. brontispae parasitization, although 2-h to 2-day-old hosts were preferred. We also demonstrated that sex ratio, emergence rate, and egg to adult developmental time were not influenced by host density, parasitoid, and host age in both choice and no-choice tests. Our data will allow for more accurate prediction and interpretation on the parasitization by T. brontispae, supporting mass-production initiatives and mass release in programs of B. longissima.

Pseudogene integrator complex subunit 6 pseudogene 1 (INTS6P1) as a novel plasma-based biomarker for hepatocellular carcinoma screening

In this study, we aimed to determine whether the pseudogene integrator complex subunit 6 pseudogene 1 (INTS6P1) in plasma could be used as a novel approach to screen for and detect hepatocellular carcinoma (HCC). We explored the clinical role of INTS6P1: First, the expression level of INTS6P1 was measured in a cohort of 33 HCC tissue samples and adjacent normal liver tissue, next, the INTS6P1 expression was detected in the culture medium and tumor cells in a cellular experiment, and last, the diagnostic performance of INTS6P1 was examined in an independent cohort of 100 people. The expression level of INTS6P1 was remarkably downregulated in the HCC tissues compared with that in the normal liver tissues (p = 0.0066). In plasma, the INTS6P1 levels were significantly decreased in HCC patients compared with non-HCC patients (p < 0.01). Additionally, we inferred that INTS6P1 might be a prospective biomarker for screening HCC patients in which the serum-AFP levels were lower than 20 ng/ml by the area under the curve-receiver operating characteristic (AUC-ROC) analysis (p < 0.05). Pseudogene INTS6P1 could be used as a novel HCC plasma-based biomarker and might improve the accuracy of HCC screening.

Chinese lacto-vegetarian diet exerts favorable effects on metabolic parameters, intima-media thickness, and cardiovascular risks in healthy men

BACKGROUND

To investigate whether the Chinese lacto-vegetarian diet has protective effects on metabolic and cardiovascular disease (CVD).

METHODS

One hundred sixty-nine healthy Chinese lacto-vegetarians and 126 healthy omnivore men aged 21-76 years were enrolled. Anthropometric indexes, lipid profile, insulin sensitivity, pancreatic β cell function, and intima-media thickness (IMT) of carotid arteries were assessed and compared. Cardiovascular risk points and probability of developing CVD in 5-10 years in participants aged 24-55 years were calculated.

RESULTS

Compared with omnivores, lacto-vegetarians had remarkably lower body mass index, systolic and diastolic blood pressure, and serum levels of triglyceride, total cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, γ-glutamyl transferase, serum creatinine, uric acid, fasting blood glucose, as well as lower total cholesterol/high-density lipoprotein cholesterol ratio. Vegetarians also had higher homeostasis model assessment β cell function and insulin secretion index and thinner carotid IMT than the omnivores did. These results corresponded with lower cardiovascular risk points and probability of developing CVD in 5-10 years in vegetarians 24-55 years old.

CONCLUSIONS

In healthy Chinese men, the lacto-vegetarian diet seems to exert protective effects on blood pressure, lipid profiles, and metabolic parameters and results in significantly lower carotid IMT. Lower CVD risks found in vegetarians also reflect the beneficial effect of the Chinese lacto-vegetarian diet.

Primary malignant bone neoplasm: a case report of dedifferentiated chondrosarcoma in the rib and review of the literature

Dedifferentiated chondrosarcoma (DDCS) is a rare but highly malignant primary bone neoplasm, which is resistant to radiotherapy and chemotherapy. There remains uncertainly as to the best treatment of this disease and how to improve its prognosis. In this paper we reported a case of DDCS and reviewed the related literatures in order to provide references to throw a light on the histogenesis, diagnosis and therapy of this disease.

Development of a novel aspherical mirror bender for an active grating

A novel monolithic mechanical bender has been designed and fabricated to meet the requirements of an active polynomial grating in a new soft X-ray scattering and emission beamline at the National Synchrotron Radiation Research Center, Taiwan. This compact bender achieves nearly fixed center point under different bending conditions. Moreover, the compact bender can be bent to a desirable third-order polynomial surface profile to cancel the defocus and coma aberrations using two PZT actuators. Theoretical analysis reveals that the grating has unprecedented spectral resolving power. A detailed mechanical analysis has been conducted and a prototype bender was fabricated and tested. The results indicate that the performance of the bender is excellent and is therefore suitable to be used in the active grating.

[Application of continuous epidural analgesia with ropivacaine and fentanyl during delivery]

OBJECTIVE

To evaluate the safety and efficiency of ropivacaine and fentanyl for continuous epidural analgesia during delivery.

METHODS

Altogether 98 full-term primigravidas with vertex presentation were selected for this study. Epidural catheter was placed during delivery with the cervical dilation of 3 cm, and the mixture of 0.2% ropivacaine and 2 microgram/ml fentanyl at the initial dose of 5 ml was given for continuous epidural analgesia. Drug infusion was discontinued when the second stage of delivery started. Another 98 primigravidas of similar conditions without analgesia served as the control group.

RESULTS

Analgesic group showed obvious pain-relieving effect (P<0.001) during the delivery, in which the active phase was significantly shortened (P<0.05). No obvious adverse effect arose in the mother and fetuses from the administration of analgesia.

CONCLUSION

Continuous epidural analgesia by pumping ropivacaine and fentanyl is effective and convenient for pain relief during delivery, and can be beneficial to the smooth progress of delivery.

[Ion single channel signal restoration and parameters' estimation based on the hidden Markov models]

The single ion channel signal is stochastic ionic current on the order of 1 pA recorded by patch clamp. Because the weakness of the signal, the background noise always dominates in the recordings, the threshold detector traditionally used in patch clamp to denoise and restore the channel signal can't work satisfactorily. This problem was analyzed mathematically, and a signal restoring and parameters estimating scheme called HMM algorithm was studied. The algorithm has been validated by simulation and the results suggest it performs effectively in the situation of low signal to noise ratio where the threshold detector fails completely.

Handwriting Evidence in Federal Courts - From Frye to Kumho

In federal courts, the admissibility of scientific expert testimony in the last century has been governed by three major standards. The first of these standards, the "general acceptance" test, arose from the 1923 Frye v. United States (Frye) and required that any technique or method introduced in court be generally accepted by the relevant community of scientists. The more liberal "relevancy" standard of the Federal Rules of Evidence was enacted in 1975, and required the expert witness to be qualified by knowledge, skill, experience, training, or education. Finally, the "reliability" standard stated in the Daubert v. Merrell Dow Pharmaceuticals, Inc. (Daubert) opinion was handed down by the U.S. Supreme Court in 1993, supplanting the Frye general acceptance test as the sole determining factor in considering the admissibility of scientific expert testimony, and suggesting falsifiability, peer review and publication, and error rate as additional factors useful in evaluating a scientific technique. Changing views on expert testimony have also resulted in published criticisms of several forensic fields, especially those with subjective components. The first such field to be questioned, which also has been the subject of great debate, is expert handwriting identification. Challenges leveled against handwriting identification began with a law review article published in 1989 (and two subsequent articles); other challenges have been based on the requirements outlined in the Federal Rules of Evidence and Daubert. These challenges resulted in several court opinions with disparate views of handwriting identification, though testimony by an expert in the field was not rejected. In U.S. v. Starzecpyzel, handwriting evidence was admitted as nonscientific expert testimony under the Federal Rules of Evidence after failing a review under the factors outlined in Daubert. In U.S. v. Velasquez (Velasquez), the testimony of a document examiner was accepted, while the testimony of an expert critic of handwriting identification was rejected by the district court; however, on appeal, the Third Circuit held that both witnesses met the requirements of the Federal Rules of Evidence, and thus both testimonies were admissible. U.S. v. Jones (Jones) demonstrated yet another situation, where handwriting identification was challenged under Daubert. There the court found that because handwriting identification was never viewed as scientific evidence under Frye, it should not therefore be reviewed under Daubert. The Jones court admitted handwriting identification as nonscientific evidence, but stated that admissibility of nonscientific evidence should be governed by the facts of future cases. After some time and many other opinions on the admissibility of expert testimony under Daubert, several federal circuits permitted review of nonscientific expert testimony under the factors outlined in Daubert, while other federal circuits restricted such reviews only to purportedly scientific testimonies. In the latter arenas, determining whether handwriting identification was a scientific field or not had bearing on how it was reviewed for admissibility, if it was reviewed at all. This situation ended in March 1999 with the U.S. Supreme Court opinion of Kumho Tire Co., Ltd. v. Carmichael (Kumho), which held that the Daubert factors may be used for review of all expert testimony as the courts see fit, regardless of whether the field is considered scientific. In the wake of Kumho, two other cases challenged handwriting identification: U.S. v. Paul (Paul) and U.S. v. Hines (Hines). The Paul case, like Velasquez, dealt with exclusion of an expert critic of handwriting identification, and also like Velasquez, the court appeared to rely on the Federal Rules of Evidence rather than the factors outlined in Daubert to form its judgment. Hines, however, represented a significant departure from earlier cases, as handwriting identification was partially excluded in that the document examiner was permitted to testify to similarities and differences but was not allowed to opine as to the authorship. In sum, the federal courts are currently evaluating the admissibility of handwriting identification in a variety of ways. Though handwriting identification continues to be widely admitted as a form of expert testimony, the recent changes in admissibility requirements and challenges from the legal community have generated a climate where admissibility should no longer to be taken for granted. Because Kumho is a relatively recent case, its long-term effects on the admissibility of many fields of forensic science, including handwriting identification, are yet unknown.

Gating kinetics of potassium channel and effects of nerve growth factors in PC12 cells analyzed with fractal model

AIM

To study the gating kinetics of voltage-dependent K+ channels i n clonal pheochromocytoma (PC12) cells and the effect of nerve growth factor (NGF) on it.

METHODS

Outward currents of K+ channel were recorded in PC12 cells cultured with or without NGF using cell-attached patch-clamp technique. The kinetic features of K+ channel and the effect of NGF on them were analyzed based on t he fractal model.

RESULTS

The fractal dimension D for the closed durations of K+ channel in PC12 cells cultured without NGF was proportional to the absolute value of the pipette potential (Vp). Whereas the fractal dimension D' was inversely proportional to it. Under pipette potentials of 0, -30, -50, and -70 mV, the values of D were 1.75, 1.88, 1.95, and 2; and of D' were 1.51, 1.40, 1.34, and 1.23. After the addition of NGF the changes in the fractal dimensions became more complex. At the same pipette potential, fractal dimensions for K+ channel in PC12 cells cultured with NGF for both the open and closed durations were not greater than those in PC12 cells cultured without NGF. The kinetic setpoints for both the close and open durations did not vary with the pipette potential with values as follows: A (without NGF) = 0.29 +\ -0.05, A(with NGF) = 0.71 +\- 0.06, A' without NGF) = 0.110 +\- 0.020, and A' (with NGF) = 0.38 +\- 0.08.

CONCLUSION

The voltage dependence of D (without NGF) increases the probability of the channel for remaining closed for long durations as the patch is depolarized, and that of D' (without NGF) decreases the probability of the channel for remaining open for long durations as the patch is depolarized. The addition of NG F in the PC12 cell culture accelerates the dynamic process of the K+ channel occurring over long time scales.

[The development of event related-potential acquisiting system]

A system for acquisiting event-related-potential signalsis presented, making use of random-sequences visial symbols. ATMEL AT89C51 controls Max 186 serial conversion and interface Max202 to serially send data to host computer for poct processing.

[Design of a data acquisition circuit for ventricular late potentials and electrocardiogram]

This paper introduces a data acquisition circuit that is able to acquire ventricular late potentials and standard 12-lead electrocardiogram signals. This circuit adopts time interruption acquisition, it has the characteristics of programmed gain, isolated ground, low-noise, high-CMRR, collecting data for a long time.

A mixture of antioxidants and fatty acids improves the viability of cultured rat hepatocytes untreated or treated with doxorubicin

The objective of this study was to determine whether medium supplementation by antioxidants and fatty acids would improve the viability of cultured rat hepatocytes and protect them against doxorubicin toxicity. We examined the effects of three agents: vitamin E, sodium pyruvate and egg yolk (the combination of vitamin E, sodium pyruvate and fatty acids is a proprietary, patented technology of Warner Lambert called CRT) 0.3% (v/v) as a source of fatty acids, on cell viability measured by the dehydrogenase-dependent bioreduction of a tetrazolium salt (MTS). Untreated hepatocytes and hepatocytes treated with carbon tetrachloride (CCl(4), EC(50) 5.7 mm) or doxorubicin (1 and 30 mum) were exposed to different amounts of a mixture of antioxidants and fatty acids. The mixture, identified as 1X, provided a final concentration of 5 units of vitamin E, 0.1% egg yolk and 10 mm sodium pyruvate while the 3X and 5X mixtures contained proportionately higher concentrations of these components. The mixtures were added 18 hr prior to, simultaneously with or following treatment with doxorubicin and just simultaneously with CCl(4). Neither vitamin E, sodium pyruvate nor egg yolk alone improved viability. However, the viability of untreated hepatocytes improved significantly when the 3X mixture was added after 18 hr as indicated by determination of MTS reduction activity 24 hr later. The viability of doxorubicin treated cultures (1 and 30 mum) increased significantly when exposed either to the 3X or 5X mixtures simultaneously. A significant increase in viability was also seen when cells were exposed to the 3X mixture following doxorubicin (1 mum). The mixtures did not protect against toxicity caused by CCl(4), perhaps due to the overwhelming level of damage at its EC(50) concentration. It is proposed that the antioxidant properties of vitamin E and sodium pyruvate protect the cells from low levels of reactive oxygen species generated spontaneously in culture and by doxorubicin metabolism while the fatty acids help to maintain the integrity of hepatocyte membranes, resulting in greater viability of the hepatocytes.

Normocalcemic effect of gallium nitrate in a hypercalcemic rat model

An established rat hypercalcemia model was used to study the effects of gallium nitrate on elevated serum calcium levels. Gallium nitrate was administered by i.v. or i.p. injection at daily doses of 0.07-0.45 mmol/kg for 5 days to the hypercalcemic rats beginning 1 day following surgery. A dose-correlated normocalcemic response was observed. Gallium nitrate administered late after the induction of the hypercalcemic state was also effective in reducing serum calcium levels. The p.o. administration, however, even at doses as high as 0.45 mmol/kg, did not reduce serum calcium to normal levels. The values of area under the concentration versus time curve (0-24 h) of gallium in normal rats were comparable after i.v. [49.2 (micrograms/ml)h] or i.p. [57.0 (micrograms/ml)h] injections. In contrast, the p.o. route achieved only 15% bioavailability, which may explain the ineffectiveness of p.o. administered gallium nitrate at that dose level. This study suggests that daily i.v. bolus injections of gallium nitrate for managing hypercalcemia may be potentially as effective as the current regimen of continuous i.v. infusion.

In vitro neutralization of the inhibitory effect of Microcystin-LR to protein phosphatase 2A by antibody against the toxin

Microcystin-LR (MCYST-LR) was found to be a very potent protein-phosphatase 2A (PP2A) inhibitor at an ID50 as low as 0.1 nM. Comparing to calyculin A and okadaic acid, MCYST-LR was found to be about 100 times stronger than calyculin A and okadaic acid for their inhibition to PP2A. The inhibitory effect on PP2A by MCYST-LR was abolished when antibodies against MCYST-LR were present in the assay system. Polyclonal antibodies were more effective than monoclonal antibodies in reversing the inhibitory effect. A dose-dependent neutralization of the inhibitory effect of MCYST to PP2A by anti-MCYST polyclonal antibodies were observed. Almost 80% of the enzyme activity was restored when as low as 0.012 micrograms of Pab was present. The specific reaction caused by the antibody was evident from an analysis that the antibodies had no effect on reversing the inhibition of PP2A caused by okadaic acid and calyculin A.

[The in vitro potentiation of LAK cell cytotoxicity in cancer and aids patients induced by F3--a fractionated extract of Astragalus membranaceus]

The in vitro induction of LAK cell activity was studied in cancer and AIDS patients. F3, an immuno-regulatory component of Astragalus membranaceus was shown capable of potentiating the LAK cell inducing activity of rIL-2. The killing activity against Hs294T melanoma cell line of LAK cells induced by 50 U/ml rIL-2 in the presence of F3 (55 micrograms/ml) reached 64% which was comparable to that (60%) induced by 500 u/ml of rIL-2 alone. With F3 plus rIL-2, the effector to target cell ratio could be reduced to one-half in order to obtain an equivalent level of cytotoxicity when rIL-2 was used alone. In some patients, whose peripheral blood lymphocytes were relatively inert to rIL-2, F3 could make them responsive to rIL-2. These results imply that F3 may be useful to potentiate LAK cell activity, reduce the amount of rIL-2 and thus minimize the later's toxic side effects when used in vivo.

Determination of peplomycin in mouse tissues and biofluids by radioimmunoassay

Peplomycin, an antitumour antibiotic analogue of bleomycin, was measured in mouse tissues using a rapid radioimmunoassay. Antiserum, obtained by immunizing rabbits with peplomycin-bovine serum albumin conjugate, showed no significant cross-reactivity with the closely related peplomycin analogues bleomycin and liblomycin, nor with a number of other structurally unrelated antitumour drugs. The assay is sensitive and can detect peplomycin levels as low as 2 ng ml-1. The relative intra- and inter-assay standard deviation is < or = 5%, indicating good assay reproducibility. Peplomycin levels in mouse tissues were easily determined without extraction. Fifteen minutes after administration of a single intraperitoneal dose of peplomycin at 8.5 mg kg-1 (1/10 of LD50), high drug levels were found in plasma (46 micrograms ml-1), kidneys (38 micrograms g-1), urine and bladder (32 micrograms ml-1), followed by gastrointestinal tract (13 micrograms g-1), lung (8 micrograms g-1), spleen (3.7 micrograms g-1), heart (3.6 micrograms g-1), gall bladder (2.7 micrograms g-1), liver (2 micrograms g-1), and brain (0.6 microgram g-1). The total amount of drug in all these organs accounted for more than 80% of the dose administered. We conclude that the radioimmunoassay is sensitive and reproducible and is an ideal tool for measuring peplomycin in tissues and biofluids for pharmacological studies.

[Oral complications following a herpes zoster infection of trigeminal nerve]

A case of herpes zoster involving the ophthalmic and maxillary divisions of the trigeminal nerve is reported. It presented as a oral herpes zoster infection with prodromal odontalgia and progressed to spontaneous exfoliation and devitalization of teeth and osteonecrosis of the maxilla. The literature is reviewed and the pathophysiology of tooth exfoliation, tooth devitalization and osteonecrosis by V-Z viruses are discussed in addition to the management of herpes zoster and post-zoster complications.

Depletion of patients' plasma tryptophan using tryptophan side-chain oxidase columns

The use of the enzyme tryptophan side-chain oxidase, isolated from Pseudomonas XA, was explored in 3 patients with refractory acute lymphocytic leukemia. Patients were given either a low-tryptophan diet or tryptophan-free hyperalimentation, prior to and during therapy. Their plasma, separated by pheresis, was continuously passed through a tryptophan depletion column containing the immobilized tryptophan side-chain oxidase. Up to 4 plasma volumes were passed through the column daily, 5 days per week for 2-3 weeks, and plasma tryptophan levels, both free and total, were measured by high-performance liquid chromatography. Pre- and postcolumn plasma samples were collected throughout the pheresis procedure. All postcolumn plasma samples had unmeasurable tryptophan levels throughout the treatment period, whereas precolumn samples were always measurable. Generally, tryptophan levels of plasma isolated from peripheral blood decreased after therapy, but rebounded by the next day. The enzyme depletion column reduces circulating plasma tryptophan levels, and its use is well tolerated by patients. However, further development of this method will require study of the effects of diet and of the duration, interval, and frequency of use of this column on therapeutic efficacy. Problems include difficulties with extended diet compliance and apparently intensive mobilization of tryptophan from body stores, which may preclude the clinical application of this enzyme depletion column.

Determination of plicamycin in plasma by radioimmunoassay

This article describes a method for the determination of plicamycin in plasma by radioimmunoassay. The anti-plicamycin antibody was produced against a plicamycin-bovine serum albumin conjugate prepared by using diazotized p-aminobenzoic acid as a cross-linker. The radiolabeled ligand, 125I-plicamycin, was prepared by the chloramine-T method. The linear plicamycin concentration range was 7-400 ng/ml. The coefficients of variation for intra- and interday variabilities were 7.5 and 15%, respectively. No interference was observed from either the structurally related chromomycin A or concomitantly used drugs hydroxyurea or allopurinol. With this method of testing, plicamycin levels in plasma could be determined in patients receiving small (0.85-1.0 mg/m2) therapeutic plicamycin doses. Preliminary pharmacokinetic data in humans indicate that the plasma drug disappearance curve was biphasic with a mean elimination half-life of 10.6 +/- 1.7 h, total clearance rate of 11.1 +/- 0.4 ml/min/m2, and area under the plasma drug concentration-time curve of 1,289-1,546 ng-h/ml. This assay method is clinically useful for pharmacokinetic studies of plicamycin and may be helpful in the design of rational therapeutic drug trials.

Characterization of a monoclonal antibody which is an activator of rabbit platelets

A monoclonal antibody (MAb) raised against rabbit platelet membranes was shown to be a strong agonist to induce platelet aggregation and secretion. This MAb, designated 19CB-1, was identified as an IgM and purified to near homogeneity by ammonium sulfate precipitation and Q-sepharose column chromatography. Aggregation induced by 19CB-1 was only slightly affected in the presence of creatine phosphate/creatine phosphokinase and aspirin, indicating that it was not mediated through the cyclooxygenase pathway and the release of ADP. 19CB-1 Fab fragments did not induce platelet aggregation. However, 19CB-1-induced aggregation was inhibited by these Fab fragments. 19CB-1 also elicited a rise in cytoplasmic calcium concentration in fura-2 loaded platelets. In the absence of external calcium, a substantial calcium signal remained to be observed, suggesting the release of calcium from intracellular stores in response to 19CB-1. This MAb reacted primarily with a polypeptide of Mr = 57,000, as revealed by immunoblotting. These results suggest that the 57 kDa antigen is one of the platelet surface proteins directly involved in the activation of rabbit platelets.

Clinical pharmacology of 1-beta-D-arabinofuranosyl-5-azacytosine (fazarabine) following 72-hour infusion

The clinical pharmacology of fazarabine (1-beta-D-arabinofuranosyl-5-azacytosine), a structural analogue of 1-beta-D-arabinofuranosylcytosine (ara-C) and 5-azacytidine, was assessed in 14 patients with various malignancies during a phase I trial. Since the starting dose for the protocol was low (0.2 mg/m2/hr over a 72-hr continuous iv infusion), a radioimmunoassay (RIA) using commercially available ara-C antibody and [3H]ara-C was developed to measure the anticipated low plasma drug levels. The assay could be used to measure fazarabine accurately in plasma and urine with a sensitivity of 0.08 ng/ml. The RIA does not require extraction of samples. Using both RIA and HPLC, similar results were obtained in plasma samples from a patient receiving a high dose (180 mg/m2/hr) of fazarabine. The assay is simple, sensitive, reproducible, and specific. Following the infusion, plasma levels declined triphasically with a terminal half-life of 5.7 +/- 2.0 hr. The AUC was linearly related to dose. When the various doses were normalized to 1.75 mg/m2/hr (the maximum tolerated dose as determined from the phase I trial) the mean AUC value was 4232 +/- 987 (ng/ml)hr. Plasma steady-state drug levels (CPss) were achieved in 2-4 hr and were linearly dependent to dose. Also, when normalized, the mean CPss was 58 +/- 13 ng/ml, which is within the reported concentration range necessary for inhibiting malignant cell growth. Total clearance was rapid, 528 +/- 138 ml/(m2.min), and not dose-related.

Aortic and pulmonary input impedance in patients with cor pulmonale

The hydraulic load of the right and left ventricles and the clinical effects of nifedipine were evaluated in 8 normal subjects (mean age: 55 years) and 8 patients with cor pulmonale secondary to chronic obstructive lung disease (mean age: 57 years). It was found that there were differences in the right ventricular resistance (174.62 +/- 25.96 vs 468.57 +/- 178.81 dyne/sec/cm-5), first zero crossing frequency (3.62 +/- 0.34 vs 6.07 +/- 3.56 Hz), steady power (218.95 +/- 32.25 vs 359.44 +/- 37.46 mW) and total power of right ventricle (275.81 +/- 36.18 vs 440.46 +/- 85.16 mW) between the normal and cor pulmonale patients, respectively. However, no significant changes in characteristic impedance, pulsatile power or aortic impedance were observed in the right pulmonary artery. After administration of nifedipine to patients with cor pulmonale, there were significant changes in resistance (468.57 +/- 178.81 vs 256.36 +/- 178.56 dyne/sec/cm-5), steady power (359.44 +/- 37.46 vs 225.51 +/- 114.64) and total power (440.46 +/- 85.16 vs. 289.27 +/- 50.85) of the pulmonary artery, respectively. Otherwise there were no significant changes in aortic input impedance or characteristic impedance of right pulmonary artery and pulsatile power. In conclusion, we found that: 1) the hydraulic vascular load in the right ventricle was higher in patients with cor pulmonale, 2) characteristic impedance that was not increased in cor pulmonale patients may be due to a dilated pulmonary artery, 3) there was no impedance mismatch between left ventricle and systemic arterial system in patients with cor pulmonale, and 4) by reducing the pulmonary vascular resistance through nifedipine administration, the total external right ventricular power might be reduced, without affecting the proximal pulmonary arterial compliance.

Liblomycin-mediated DNA cleavage in human head and neck squamous carcinoma cells and purified DNA

Liblomycin (LBM), a novel bleomycin analogue, and bleomycin A2 (BLM A2) were compared with respect to their relative potential to inhibit growth in a human head and neck squamous carcinoma cell line and to produce DNA damage within cellular DNA and nuclei DNA and against isolated naked DNA. Against the BLM-sensitive cell line 183A, the concentration of LBM that inhibits cell growth by 50% was 1.1 microM for a 30-min drug exposure, while it was 23 microM for BLM A2. Drug-mediated DNA double-strand cleavage within cells was compared with the relative ability of these drugs to produce DNA cleavage in isolated 183A cell nuclei. Though 30-min exposures of cells to equimolar concentrations of both drugs resulted in 4-fold greater cellular DNA damage by LBM than BLM A2, the two drugs were nearly equipotent in producing DNA injury within isolated nuclei. Against Simian virus 40 DNA, however, LBM was 10-fold less effective than BLM A2 in producing Forms II and III DNA from Form I DNA. Radioactivity from either [3H]BLM A2 or 125I-LBM found associated with cells after a 30-min incubation period was also assessed in the 183A cell line. The exposure of cells to radiolabeled drug (1 microM) resulted in a 71-fold greater amount of cell-associated radioactivity for LBM than for BLM A2. The relative abilities of the 183A cell line to partially reseal LBM- or BLM A2-mediated DNA double-strand breaks were also assessed. No preferential repair of overall drug-mediated DNA injury, however, was observed. Finally, drug-mediated specific cleavage sites on pBR322 DNA were determined. At doses that gave the same extent of DNA cleavage, both BLM A2 and LBM gave similar patterns of strand scission, although minor differences were observed. Taken together, these data demonstrate that the greater efficacy of LBM against the BLM-sensitive head and neck squamous cell line is due mainly to LBM's greater association with cells over a defined time period, even though the DNA cleaving ability of LBM is relatively lower than that of BLM A2.

[Immune restoration of local xenogeneic graft-versus-host reaction in cancer patients in vitro and reversal of cyclophosphamide-induced immune suppression in the rat in vivo by fractionated Astragalus membranaceus]

Through the process of fractionation, purification by gel filtration chromatography and thereafter the screening with an in vitro local xenogeneic graft-versus-host reaction (XGVHR) model, a fraction was identified as a potent immunorestorative agent and was designated "Fraction 3" (F3). Using the XGVHR in vitro as a model assay for T cell function again, F3 was studied on mononuclear cells (MNC) from 13 cancer patients and exhibited significant immunorestorative activity, with an increase in local XGVHR (compared to untreated cells) of 151.34 +/- 46.02 mm3 vs 57.80 +/- 16.44 mm3, P less than 0.001. The in vitro augmented immune reactions induced by F3 in cancer patients also significantly exceeded the local XGVHR observed in the untreated MNC derived from 9 normal donor controls (94.15 +/- 9.16 mm3, P less than 0.005). In a newly developed in vivo XGVHR animal model, pretreatment of rats with F3 resulted in a significant abrogation of the local XGVHR with a reversal of the immunosuppressive effect of cyclophosphamide from 99.42 +/- 9.2 mm3 (positive control) to 39.78 +/- 8.3 mm3 (P less than 0.001). This reversal was complete as the volume of the abrogated local XGVHR was comparable to that of the negative control (no cyclophosphamide-priming, saline injection only) 34.79 +/- 5.69 mm3 (P greater than 0.1). These results suggest that F3 retained the immunopotentiating activity of the original crude extract and form the rational basis for the use of Astragalus in immunotherapy.

Diagnosis and treatment of giant cell tumor in the thoracic spine

A 23-year-old woman with incomplete paralysis was operated upon for a giant cell tumor in the thoracic spine. X-ray films revealed a destruction lesion in the vertebral body of the 12th thoracic vertebra. On the plain thoracic computed tomography scan, the finding was a soap-bubble appearance with a linear high density area in the mass lesion which destroyed the vertebral body. Preoperative angiography showed no apparent feeding artery to the tumor tissue; preoperative myelography showed incomplete block at the level of the 12th thoracic vertebra. A radical operation was carried out in one stage via a combined antero-posterior approach. In order to give radiotherapy immediately after operation, a vascular pedicled rib graft was made. This paper discusses the role of thoracic computed tomography scan in the diagnosis of giant cell tumor and the surgical techniques used in treatment.

Polyethylene glycol-L-asparaginase and L-asparaginase studies in rabbits

Injections of polyethylene glycol (PEG)-L-asparaginase or L-asparaginase were given to two rabbits each at doses of 40 units/kg. Ten min following injection of either enzyme preparation, the plasma enzyme concentration was approximately 1 unit/ml. This level decreased steadily in the rabbits given L-asparaginase, with a t1/2 of approximately 20 hr. In contrast, the enzyme level in rabbits given PEG-L-asparaginase decreased much more slowly, with a t1/2 of approximately 144 hr. The slower disappearance rate of PEG-L-asparaginase resulted in greater values for the area under the concentration versus time curve and smaller values for total clearance. Immediately following the enzyme injections, no L-asparagine could be detected in the plasma, and a transient elevation of L-aspartic acid levels was noted. By 4 hr, the L-aspartic acid level in all of the rabbits returned to near normal. The L-asparagine, however, was not measurable as long as plasma enzyme was detectable. Levels of L-asparagine returned to normal 4 days after L-asparaginase administration, and 27 days elapsed before L-asparagine was detected in rabbits given PEG-L-asparaginase.