[Predictive value of left ventricular ejection fraction for the occurrence of postoperative myocardial infarction after coronary endarterectomy in patients with diffuse coronary artery disease]

Objective: To investigate the predictive value of ejection fraction for the postoperative myocardial infarction after coronary endarterectomy (CE) in patients with diffuse coronary artery disease (DCAD). Methods: Patients who underwent cardiac artery bypass graft (CABG) surgery and CE in Beijing Anzhen Hospital affiliated to Capital Medical University from May 2018 to December 2020 were enrolled in this prospective observational study. Baseline features including age, sex and echocardiography parameters were obtained. Left ventricular ejection fraction(EF) was measured by echocardiography. The patients were divided into postoperative myocardial infarction (PMI) group and non-PMI group according to PMI occurrence. Linear regression analysis, logistic regression model, and receiver operating characteristic(ROC) curve were used to analyze the correlation between left ventricular ejection fraction and PMI and the influencing factors. Results: A total of 120 patients were enrolled in the study. There were 32 patients (27%) in the PMI group (male 27(84%), age (62±8)), inferior myocardial infarction occurred in 24 (75%) patients. There were 88 patients (73%) in the non-PMI group (male 70(80%), age (62±8)). EF (55% (49%, 64%) vs. 62% (55%, 67%), P=0.01) was significantly lower in the PMI group than in the non-PMI group. Perioperative TNI, IABP use and length of hospitalization were significantly higher in the PMI group than in the non-PMI group. Multivariate logistic regression showed that lower EF was an independent risk factor of PMI (OR=0.93, 95%CI: 0.89-0.98, P=0.01) after adjusting age, sex and body mass index. ROC curve analysis showed that EF<60% could sufficiently predict the occurrence of PMI (AUC= 0.67, sensitivity 64%, specificity 69%, P=0.01). Linear regression analysis showed that left ventricular end-diastolic diameter (OR=-0.52, 95%CI:-1.13-0.60, P<0.001), graft flow in left anterior descending (OR=-0.20, 95%CI:-0.15-0.01, P=0.02) and history of diabetes (OR=-0.28, 95%CI:-8.25-1.85, P=0.002) were negatively correlated with preoperative EF value. Conclusion: Lower preoperative EF is an independent risk factor for PMI after CABG and CE in DCAD patients, closely related to the left ventricular end-diastolic diameter, graft flow in left anterior descending artery and diabetes mellitus.

Neurology of COVID-19 in Singapore

PURPOSE

To describe the spectrum of COVID-19 neurology in Singapore.

METHOD

We prospectively studied all microbiologically-confirmed COVID-19 patients in Singapore, who were referred for any neurological complaint within three months of COVID-19 onset. Neurological diagnoses and relationship to COVID-19 was made by consensus guided by contemporaneous literature, refined using recent case definitions.

RESULTS

47,572 patients (median age 34 years, 98% males) were diagnosed with COVID-19 in Singapore between 19 March to 19 July 2020. We identified 90 patients (median age 38, 98.9% males) with neurological disorders; 39 with varying certainty of relationship to COVID-19 categorised as: i) Central nervous system syndromes-4 acute disseminated encephalomyelitis (ADEM) and encephalitis, ii) Cerebrovascular disorders-19 acute ischaemic stroke and transient ischaemic attack (AIS/TIA), 4 cerebral venous thrombosis (CVT), 2 intracerebral haemorrhage, iii) Peripheral nervous system-7 mono/polyneuropathies, and a novel group, iv) Autonomic nervous system-4 limited dysautonomic syndromes. Fifty-one other patients had pre/co-existent neurological conditions unrelated to COVID-19. Encephalitis/ADEM is delayed, occurring in critical COVID-19, while CVT and dysautonomia occurred relatively early, and largely in mild infections. AIS/TIA was variable in onset, occurring in patients with differing COVID-19 severity; remarkably 63.2% were asymptomatic. CVT was more frequent than expected and occurred in mild/asymptomatic patients. There were no neurological complications in all 81 paediatric COVID-19 cases.

CONCLUSION

COVID-19 neurology has a wide spectrum of dysimmune-thrombotic disorders. We encountered relatively few neurological complications, probably because our outbreak involved largely young men with mild/asymptomatic COVID-19. It is also widely perceived that the pandemic did not unduly affect the Singapore healthcare system.

Encephalopathy in COVID-19 patients; viral, parainfectious, or both?

We describe the clinical, laboratory and radiological features of 3 critically ill patients with COVID-19 who developed severe encephalopathy. The first patient did not regain consciousness when sedation was removed at the end of 2 weeks of intensive care. He had received treatment with convalescent plasma. His clinical examination was remarkable for intact brainstem reflexes, roving eye movements, later transient ocular flutter; and then what appeared to be slow ocular dipping. He had no coherent volitional response to the environment. The second patient recovered with measurable cognitive deficits after a prolonged period of encephalopathy. He had received combination treatment with interferon beta 1b and lopinavir/ritonavir. The third patient remained in persistent, severe agitated delirium and died 3 months into his illness. The MRI of the 3 patients showed multifocal abnormalities predominantly in the cerebral white matter, with varying involvement of the grey matter, brainstem and spinal cord. Case 1's MRI changes were consistent with acute disseminated encephalomyelitis. The patients also displayed blood markers, to varying degree, of autoimmunity and hypercoagulability. We were not able to convincingly show, from microbiological as well as immunological evaluation, if the effects of COVID-19 on these patients' nervous system were a direct consequence of the virus, proinflammatory-thrombotic state or a combination. Patient 1 responded partially to empirical, albeit delayed, therapy with intravenous immunoglobulins. Patient 2 recovered with no specific treatment. These cases illustrate the need to understand the full spectrum of encephalopathy associated with COVID-19 so as to better guide its management.

•

We describe three severe COVID-19 patients with encephalopathy.

•

We hypothesize possible underlying pathophysiology; viral, parainfectious or both.

•

We discuss the dilemma we faced in their diagnosis and management.

Phenotypic bases of NOTCH2NLC GGC expansion positive neuronal intranuclear inclusion disease in a Southeast Asian cohort

Neuronal intranuclear inclusion disease (NIID) is a neurodegenerative disorder associated with GGC repeats of >60 to 500 copies in the 5'-untranslated region of NOTCH2NLC. The clinical and genetic characterization of NIID outside of East Asia remains unknown. We identified twelve patients who underwent genetic testing using long-read sequencing or repeat primed polymerase chain reaction. All were positive for a GGC repeat expansion; the median repeat length was 107 (range 92-138). Ten were Chinese and two of Malay ethnicity. Age at onset ranged from 50 to 69 years. Eight (66.7%) patients had dementia, while four (33.3%) patients were oligosymptomatic, without typical NIID symptoms of dementia, Parkinsonism, or muscle weakness. GGA interruptions within the GGC expansion were present in four patients; the number of GGA interruptions was highest (6.71%) in the patient with the earliest age at onset (50 years). Median plasma neurofilament light level was 47.3 pg/mL in seven patients (range 26-380 pg/mL). The highest level (380 pg/mL) was found in one patient who experienced an encephalitic episode. Overall, we describe a cohort of genetically confirmed NIID patients from Southeast Asia and provide further information that the presence of GGA interruptions within GGC repeat expansions may serve as a potential genetic modifier in NIID.

NOTCH2NLC GGC Repeat Expansions Are Associated with Sporadic Essential Tremor: Variable Disease Expressivity on Long-Term Follow-up

We screened 662 subjects comprising 462 essential tremor (ET) subjects (285 sporadic, 125 with family history, and 52 probands from well-characterized ET pedigrees) and 200 controls and identified pathogenic NOTCH2NLC GGC repeat expansions in 4 sporadic ET patients. Two patients were followed up for >1 decade; one with 90 repeats remained an ET phenotype that did not evolve after 40 years, whereas another patient with 107 repeats developed motor symptoms and cognitive impairment after 8 to 10 years. Neuroimaging in this patient revealed severe leukoencephalopathy; diffusion-weighted imaging hyperintensity in the corticomedullary junction and skin biopsy revealed intranuclear inclusions suggestive of intranuclear inclusion body disease (NIID). No GGC repeats of >60 units were detected in familial ET cases and controls, although 4 ET patients carried 47 to 53 "intermediate" repeats. NOTCH2NLC GGC repeat expansions can be associated with sporadic ET. Carriers presenting with a pure ET phenotype may or may not convert to NIID up to 4 decades after initial tremor onset. ANN NEUROL 2020;88:614-618.

Correction to: atypical radiological findings of primary central nervous system lymphoma

The above article was published with incorrect list of authors. We have added Seyed Ehasan Saffari and his affiliation as the addition of the new author to the author list was requested at revision stage.

[Exposure to famine in fetus and infant period and risk for hypertension in adulthood]

Objective: To investigate the relationship between exposure to famine in fetus and infant period and the risks for hypertension in adulthood. Methods: A total of 5 960 participants born between 1956 and 1965 were included in the study and were divided into unexposed group (1963-1965), fetal exposed group (1959-1961), early- childhood exposed group (1956-1958) and transitional group (1962). Logistic regression model was used to explore the association between famine exposure in early life and the risk for hypertension in adulthood. Results: Both the fetal exposure and the early-childhood exposure were the risk factors for hypertension in adulthood (OR=1.249, 95%CI: 1.049-1.486 and OR=1.360, 95%CI: 1.102-1.679). Meanwhile, in rural area, compared with unexposed group, the fetal exposure (OR=1.401, 95%CI: 1.091-1.798) and the early-childhood exposure (OR=1.460, 95%CI: 1.145-1.862) were also associated with a greater risk of hypertension in adulthood. In addition, fetal exposure and early-childhood exposure to famine in women were associated with 36.0% and 31.9% increased risks for hypertension (95%CI: 7.8%-71.7% and 95%CI: 4.8%-66.0%) according to the stratified analysis. Conclusion: Fetal exposure to famine might increase the risk for hypertension in adulthood.

Atypical radiological findings of primary central nervous system lymphoma

PURPOSE

Primary central nervous system lymphoma (PCNSL) presenting with atypical radiological findings often leads to delayed diagnosis. We aim to characterize the radiological features and apparent diffusion coefficient (ADC) values of PCNSL with atypical neuroimaging presentation in our local population.

METHODS

We retrospectively reviewed all patients with histological diagnosis of CNS lymphoma at our tertiary center from 2005 to 2016. We screened all initial pre-treatment MRIs and excluded cases with typical imaging findings of contrast-enhancing lesions without intra-lesional susceptibility and central non-enhancement. Additional exclusion criteria included (i) relapsed PCNSL, (ii) secondary CNS lymphoma, and (iii) positive HIV status. Two independent raters scored MRI and CT scans at presentation. We computed ADC values in the tumors by 2 methods: single region of interest (ROI1) and multiple ROI (ROI2).

RESULTS

Sixteen (25.4%) of 63 patients with CNS lymphoma met inclusion criteria. There were 8 men; median age was 61 (range 22-81) years. Histological diagnoses were diffuse large B cell lymphoma (n = 14) and intravascular lymphoma (n = 2). Fifteen (93%) patients had enhancing lesions (5 solitary; 10 multifocal); most enhancing lesions had T1 hypointense (67%) and T2 mixed (53%) signals, and 6 (40%) had central non-enhancing regions. Nine (56%) patients had lesions with susceptibility. Using the ROI methods, median values for minimum ADC and mean ADC ranged 0.65-0.71 × 10^-3 mm²/s and 0.79-0.84 × 10^-3 mm²/s respectively.

CONCLUSION

PCNSL with atypical radiological features represented one-fourth of our histologically diagnosed lymphoma cases; low ADC values in atypical lesions should prompt clinicians to consider early biopsy for definitive diagnosis.

[Clinical characteristics of LC-BPPV patients with bilateral direction-fixed horizontal nystagmus in primary Roll test]

Objective:To investigate the clinical features of LC-BPPV with direction-fixed horizontal nystagmus in the primary Roll test. Method:Nine patients of LC-BPPV with bilateral direction-fixed horizontal nystagmus in the first Roll test were treated by repositioning maneuvers after judging the affected side and the prognosis was observed. Result:The affected side of eight patients was the side of the apogeotropic nystagmus. Barbecue or Gufoni maneuvers was effective for reposition. The other one had no conversion of nystagmus and could not judge the affected side. Conclusion:The nystagmus performance of patients with LC-BPPV is complicated. It is necessary to carefully analyze the nystagmus performance of each position. Combining with bow and lean test, lying down test and null plane, the position of the otolith is inferred. Comprehensive use of the Barbecue or Gufoni maneuvers, forced side lying on the affected side, mastoid sniper, shaking head method is effective to complete the reposition treatment.

[Curative effect analysis of the vestibular rehabilitation training on residual dizziness after successful canalith repositioning maneuvers in patients with benign paroxysmal positional vertigo]

Objective:To explore the curative effect and quality life of the vestibular rehabilitation training on residual dizziness after successful canalith repositioning maneuvers in patients with benign paroxysmal positional vertigo (BPPV). Method:Residual dizziness after successful canalith repositioning maneuvers in patients with BPPV were enrolled in our study. They were randomized into three groups, the control group A were no disposition which include 32 patients, the intervention group B were guided to self rehabilitation training which include 33 patients, the control group C were guided to Brandt Daroff training which include 33 patients. Dizziness handicap inventory (DHI) and residual dizziness duration were used to evaluation the patients. Result:After one week vestibular rehabilitation training, the scores of DHI in group B and C decreased, and there was no significant difference (P>0.05), there were significant differences between group B and group C in group A, respectively (P<0.01). After four weeks of vestibular rehabilitation training, the scores of DHI in group B and group C were lower than those in group A, the decrease of group B was significantly higher than that of group C (P<0.01). The residual dizziness duration indicated that no statistical differences in the B, C groups (P>0.05) and scores of group B,C were significantly lower than group A (P<0.05). Conclusion:The appropriate vestibular rehabilitation training on residual dizziness after successful canalith repositioning maneuvers in patients with BPPV can help promote the central vestibular compensation, reduce the residual symptoms, improve the quality life of patients, and which can be used as the adjuvant treatment on BPPV patient who has residual dizziness symptoms.

Post-targeting strategy for ready-to-use targeted nanodelivery post cargo loading

Based on boronate formation, this study reports a post-targeting methodology capable of readily installing versatile targeting modules onto a cargo-loaded nanoplatform in aqueous mediums. This permits the targeted nanodelivery of broad-spectrum therapeutics (drug/gene) in a ready-to-use manner while overcoming the PEGylation-dilemma that frequently occurs in conventional targeting approaches.

[Research progress of intervention strategies on voice disorders in children with vocal nodules]

Vocal nodules in children is one of the common diseases in children, characterized as the hoarse voice of the children, which is mainly due to improper use of sound long-term or excessive use of the voice. The hoarseness of children's voice undermine not only the physical and mental health of children, but also the quality of life of children and their families. In recent years, the incidence of vocal nodules in children has been increasing. There are considerable differences between the children's own characteristics and adults such as bronchial lumen and cognitive and cooperate aspects, which lead to a large number of difficulties for clinical diagnosis and intervention. Based on a large number of literatures, this paper reviews the risk factors, diagnosis, voice assessment and intervention strategies of vocal nodules in children, in order to provide more comprehensive reference for the medical workers.

[Review of 1 000 Hz probe tone tympanogram applying to evaluate middle ear of infants]

1 000 Hz probe tone acoustic admittance test as a efficient method used to evaluate function of middle ear in infants, has reached consensus from domestic and foreign scholars. But there still exsits controversy on proper use in infants of months old. Here is to make a brief introduction about physiological characteristics of middle ear in infants, 1 000 Hz tympanometry and applicable age range, hoping to providing reference for future research.

Clinicoradiologic features distinguish tumefactive multiple sclerosis from CNS neoplasms

BACKGROUND

There are limited data to guide clinicians in differentiating tumefactive multiple sclerosis (TMS) from CNS neoplasms. Identifying distinguishing features will inform diagnosis and management and avoid unnecessary diagnostic biopsy. Our study aimed to determine the clinical and radiologic features that differentiate TMS from glioma and CNS lymphoma (CNSL) in patients who present with tumefactive lesions.

METHODS

We retrospectively reviewed all patients with tumefactive lesions and histologically proven or clinically diagnosed TMS, glioma, or CNSL at our tertiary center from 1999 to 2012. Two independent blinded neuroradiologists rated MRI brain scans at presentation. We correlated patients' demographic, clinical, laboratory, and radiologic data to final diagnosis.

RESULTS

A total of 133 patients (10 TMS, 85 glioma, 38 CNSL) were analyzed. Patients with TMS were younger and a greater proportion were women. Presenting symptoms did not distinguish between diagnoses. TMS lesions were smaller compared to glioma and CNSL, had no or mild mass effect, and were always associated with contrast enhancement. Radiologic features that were more frequent in TMS lesions were incomplete rim (open-ring) enhancement, incomplete peripheral diffusion restriction, and mixed T2 signal and CT hypoattenuation of MRI-enhancing components (all p < 0.05).

CONCLUSIONS

Radiologic features but not presenting symptoms are useful in distinguishing TMS from CNS neoplasms.

Reducing cranial computed tomography effective radiation dose by 30% using adaptive iterative dose reduction

Introduction:

The use of computed tomography (CT) imaging as a diagnostic modality is increasing rapidly and CT is the dominant contributor to diagnostic medical radiation exposure. The aim of this project was to reduce the effective radiation dose to patients undergoing cranial CT examination, while maintaining diagnostic image quality.

Methods:

Data from a total of 1003, 132 and 27 patients were examined for three protocols: CT head, CT angiography (CTA), and CT perfusion (CTP), respectively. Following installation of adaptive iterative dose reduction (AIDR) 3D software, tube current was lowered in consecutive cycles, in a stepwise manner and effective radiation doses measured at each step.

Results:

Baseline effective radiation doses for CT head, CTA and CTP were 1.80, 3.60 and 3.96 mSv, at currents of 300, 280 and 130–150 mA, respectively. Using AIDR 3D and final reduced currents of 160, 190 and 70–100 mA for CT head, CTA and CTP gave effective doses of 1.29, 3.18 and 2.76 mSv, respectively.

Conclusion:

We demonstrated that satisfactory reductions in the effective radiation dose for CT head (28.3%), CTA (11.6%) and CTP (30.1%) can be achieved without sacrificing diagnostic image quality. We have also shown that iterative reconstruction techniques such as AIDR 3D can be effectively used to help reduce effective radiation dose. The dose reductions were performed within a short period and can be easily achievable, even in busy departments.

Eye Globe Abnormalities on MR and CT in Adults: An Anatomical Approach

Eye globe abnormalities can be readily detected on dedicated and non-dedicated CT and MR studies. A primary understanding of the globe anatomy is key to characterising both traumatic and non-traumatic globe abnormalities. The globe consists of three primary layers: the sclera (outer), uvea (middle), and retina (inner layer). The various pathological processes involving these layers are highlighted using case examples with fundoscopic correlation where appropriate. In the emergent setting, trauma can result in hemorrhage, retinal/choroidal detachment and globe rupture. Neoplasms and inflammatory/infective processes predominantly occur in the vascular middle layer. The radiologist has an important role in primary diagnosis contributing to appropriate ophthalmology referral, thereby preventing devastating consequences such as vision loss.

Papular acantholytic dyskeratosis of the vulva associated with familial Hailey-Hailey disease

Papular acantholytic dyskeratosis (PAD) of the vulva is a rare, chronic disorder first described in 1984. It presents in young women as white to skin-coloured smooth papules over the vulva, which are persistent but asymptomatic. Histologically, there is hyperkeratosis and focal parakeratosis with acantholytic and dyskeratotic cells forming corps ronds and grains, placing PAD within Ackerman's spectrum of focal acantholytic dyskeratoses with Hailey-Hailey disease (HHD) and Darier disease. There have been 17 previous reports of PAD of the vulva, to our knowledge. Only one demonstrated a familial pattern, and none of the cases was associated with a family history of HHD. This is the first report of PAD and HHD in a single family, suggesting that PAD and HHD lie on a spectrum of disease and are genetically linked.

Molecular characterization and tissue-specific expression of invariant chain isoform in Muscovy Duck (Cairina moschata)

Invariant chain (Ii) isoform, through its thyroglobulin-like (Tg) domain, inhibits cysteine proteases during antigen presentation in vertebrates. In birds, the Ii of Muscovy Duck (MDIi) has 2 forms: MDIi-1 and MDIi-2 (MDIi isoform). To understand the genetic information and expression characteristics of MDIi-2, polymerase chain reaction, and bioinformatic analysis were performed for MDIi-2 from healthy adult Muscovy Duck. The full-length MDIi-2 cDNA sequence was found to be 1377-base pairs, encoding a 285-amino acid protein. MDIi-2 contains 63 amino acids with an insertion sequence in the Tg domain. MDIi-2 shares high identity (72.51-94.74%) with the same protein in other birds. The Tg domain of MDIi-2 is highly conserved and showed relatively high identity (96.83%) among all tested birds. The molecular structure of the Tg domain supports this conservation. MDIi-2 expression was measured in various tissues using real-time quantitative polymerase chain reaction. Similar to MDIi-1, MDIi-2 was detected in all tissues but at different levels. Higher expression level was observed in the spleen, intestinal mucosa, and bursa stipe (bursa of Fabricius stipe) than in other tissues. This suggests that MDIi-2, like MDIi-1, plays an essential role in all tissues and that its differential expression may be related to its functions in these tissues. The coexistence of 2 MDIi isoforms indicates that their functions are correlated in Muscovy Duck. This study improves the understanding of poultry immunology and may be used to improve measures to protect Muscovy Duck from disease.

Intracellular localization and association of MHC class I with porcine invariant chain

The objective was to investigate the intracellular localization and association of pig major histocompatibility complex (MHC) class I subunits with invariant chain (Ii). Pig MHC class I subunit cDNAs were cloned by RT-PCR and eukaryotic expression plasmids of α and β2m were constructed with fusions to red or enhanced green fluorescent protein (pDsRed2-N1-α, pEGFP-N1-α, pDsRed2-N1-β2m, and pEGFP-N1-β2m). A pig Ii mutant with a deleted CLIP region (DCLIP-Ii) was constructed by overlap extension PCR. Wild-type Ii and mutant Ii were cloned into pEGFP-C1 (pEGFP-C1-Ii, pEGFP-C1-DCLIP-Ii). The recombinant plasmids of MHC I subunits and pEGFP-C1-Ii (pEGFP-C1-ΔCLIP-Ii) were transiently cotransfected into COS-7 cells with Lipofectamine 2000. Immunofluorescence microscopy was performed to detect expression and intracellular localization of Ii and MHC I subunits, and immunoprecipitation was used to analyze their association. Our results indicated that pig Ii associates with integrated MHC I subunits to form oligomers, but cannot associate with single MHC I subunits. Furthermore, deletion of the Ii CLIP sequence blocks association with integrated MHC I subunits. Thus, pig Ii cannot associate with a single MHC I molecule, the α or β2m chain, but Ii and the integrated MHC I molecule can form complexes that colocalize in the endomembranes of COS-7 cells. The Ii of CLIP plays a key role in assembly of Ii and MHC I.

Molecular cloning and site-directed mutagenesis of leucine-based sorting motifs of the porcine invariant chain

Invariant chain (Ii) is a transmembrane protein that associates with MHC class II molecules in the endoplasmic reticulum. The cytoplasmic tail of Ii contains two leucine residues able to direct Ii to the endocytic pathway. We obtained the pig Ii gene by RT-PCR. Mutated Ii was prepared via site directed mutagenesis by the PCR Megaprimer method to study the effect of the two leucines on the localization of pig Ii. These mutated fragments were ligated to the vector pmCherry-C1. The recombinant plasmids were transiently transfected into COS-7 cells with Lipofectamine(TM) 2000. Fluorescence of fusion proteins (mCherry-Ii) was observed with a fluorescent microscope. Amino acid sequence alignment showed that pig Ii has domains similar to those seen in other mammalian Ii, including the cytoplasmic, transmembrane, class II-associated Ii-derived peptide, and trimerization domains. Based on observations with the fluorescent microscope, we found that two leucine-based motifs are required for pig Ii intracellular localization, and that both motifs independently mediate this function in Ii.

The effect of site-directed mutagenesis of the ambient amino acids of leucine-based sorting motifs on the localization of chicken invariant chain

Two Leu residues and their ambient amino acid residues are known to exist in the cytosolic tail of chicken invariant chain (Ii), and these play an important role as motifs in mediating the sorting endocytic pathway. We performed 20 mutations via site-directed mutagenesis by the PCR megaprimer method to study the effect of some ambient amino residues of both Leu on the localization of chicken Ii. These mutated fragments were ligated to the vector pEGFP-C1. The recombinant plasmids were transiently transfected into COS-7 cells with Lipofectamine 2000. Furthermore, the fluorescence of located fusion proteins (green fluorescent protein-Ii) was observed with a fluorescence microscope. Our results indicated that 2 Leu-based motifs are required for chicken Ii intracellular localization, and both motifs independently mediate this function of the Ii. The other amino acid residues surrounding both Leu also influence Ii-induced endosomal vacuolation. In addition, we found that Pro19, which is near the Val17-Leu18 motif, was a key residue for chicken Ii intracellular localization. Not only is it critical for endocytic targeting to each Leu, but its unique mutation can also result in altering the function of chicken Ii.

Characterization of structure and diffusion behaviour of Ca-alginate beads prepared with external or internal calcium sources

Ca-alginate beads were prepared with either external or internal calcium sources. The structures of both beads were investigated with the aid of scanning electron microscopy (SEM) and confocal microscopy. It was shown that the beads with internal calcium source had a looser structure and bigger pore size than those with external calcium source. The attempts to interpret the difference were carried out by determining the Ca content within the beads at various times, which indicated that it was the different gelation mechanisms that caused the difference of structures of both beads. Furthermore, it was also found that the diffusion rate of haemoglobin (Hb) within the beads with an internal calcium source was faster than that of the beads with an external one, which was consistent with the observation of their structures.

Highly efficient asymmetric epoxidation of alkenes with a D(4)-symmetric chiral dichlororuthenium(IV) porphyrin catalyst

A dichlororuthenium(IV) complex of 5,10,15,20-tetrakis[(1S,4R,5R,8S)-1,2,3,4,5,6,7,8-octahydro-1,2:5,8-dimethanoanthrance-9-yl]porphyrin, [Ru(IV)(D(4)-Por)Cl(2)] (1), was prepared by heating [Ru(II)(D(4)-Por)(CO)(MeOH)] (2) in refluxing CCl(4). Complex 1 is characterized by (1)H NMR (paramagnetically shifted pyrrolic protons at delta(H) = -52.3 ppm), FAB-mass spectroscopies, and magnetic susceptibility measurement (mu(eff) = 3.1 mu(B)). The ruthenium complex exhibits remarkable catalytic activity toward enantioselective alkene epoxidation using 2,6-dichloropyridine N-oxide (Cl(2)pyNO) as terminal oxidant. The Ru(IV)-catalyzed styrene epoxidation is achieved within 2 h (versus 48 h for the 2-catalyzed reaction), and optically active styrene oxide was obtained in 69% ee and 84% yield (875 turnovers). Likewise, substituted styrenes and some conjugated cis-disubstituted alkenes (e.g., cis-beta-methylstyrene, cis-1-phenyl-3-penten-1-yne, 1,2-dihydronaphthalene, and 2,2-dimethylchromenes) are converted effectively to their organic epoxides in 50-80% ee under the Ru(IV)-catalyzed conditions, and more than 850 turnovers of epoxides have been attained. When subjecting 1 to four repetitive uses by recharging the reaction mixture with Cl(2)pyNO and styrene, styrene oxide was obtained in a total of 2190 turnovers and 69% ee. UV-vis and ESI-mass spectral analysis of the final reaction mixture revealed that a ruthenium-carbonyl species could have been formed during the catalytic reaction, leading to the apparent catalyst deactivation. We prepared a heterogeneous chiral ruthenium porphyrin catalyst by immobilizing 1 into sol-gel matrix. The heterogeneous catalyst is highly active toward asymmetric styrene epoxidation producing styrene oxide in 69% ee with up to 10,800 turnovers being achieved. The loss of activity of the Ru/sol-gel catalyst is ascribed to catalyst leaching and/or deactivation. On the basis of Hammett correlation (rho(+) = -1.62, R = 0.99) and product analysis, a dioxoruthenium(VI) porphyrin intermediate is not favored.

Cross-cultural implementation of a Chinese version of the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) in Taiwan

BACKGROUND

There are no published reports of cross-cultural equivalence and interrater reliability at the level of individual symptom items assessed by a semi-structured clinical interview employing operationalised clinician ratings.

AIMS

To assess the cross-cultural clinical equivalence and reliability of a Chinese version of the World Health Organization Schedules for Clinical Assessment in Neuropsychiatry (SCAN).

METHOD

UK-US and Taiwanese groups of psychiatrists used Chinese and English transcripts of videotape interviews of Taiwanese patients to discuss cross-cultural issues and ratings of SCAN items. Item ratings were compared quantitatively individually and pooled by SCAN section.

RESULTS

Chinese equivalents were found for all SCAN items. No between-group differences were found for most individual items, but there were differences for some scaled items. Average agreement between the two groups was 69-100%.

CONCLUSIONS

Cross-cultural implementation based on SCAN in Taiwan appears valid.

[The construction and expression of two humanized scFv-urokinase fusion genes]

By using PCR and DNA recombination, two fusion genes of humanized mouse anti-human fibrin scFv and low molecular weight single chain urokinase (Scu-PA-32K) was constructed. The difference of these two fusion genes lay in the linker between two moieties, one was (Ala)3 and another was (Gly4Ser)3. These two fusion genes were both overexpressed in E. coli with the expression level at 30%. Both expression products showed the activity of binding antigen D-Dimer and activating plasminogen after the denaturation and renaturation, but under general refolding conditions, the one with linker (Gly4Ser)3 showed better effect in the renaturation of fusion protein.

[Expression of prourokinase in different mammalian cells]

Comparison studies of recombinant prourokinase(pro-UK) in various host cells, and expression vectors were carried out. Expression levels of vectors constructed in this study in different cell lines were compared. Mammalian cells expressing pro-UK were established. The levels of pro-UK expression in recombinant Namalwa, Vero and Sp2/0 cells are 200, 12.5 and 50 IU/(10(6) cells 24 h). pro-UK purities separated by immunoaffinity chromatograph are above 90%. Immunoabsorbent assay showed the ratio of pro-UK in CHO cells is lower than that from Vero and Namalwa cells. This study provide new host cells for pro-UK production.

[Construction and expression of anticolonic cancer scFv fragment]

Anticolonic cancer scFv fragment with a VH-linker-VL structure was constructed and expressed in E. coli. SDS-PAGE analysis showed the fragment cloned in pComb3 was not expressed efficiently in JM83, while cloned in pET-22b(+) highly expressed in BL21(DE3) up to 35.5% of the total bacterial protein obtained, if the culture was incubated under 30 degrees C.

[Construction and expression of a hepatocellular carcinoma specific rodent and its humanized single-chain Fv fragments in Escherichia coli]

The aim of this research is to exploit the expression strategies for two genes encoding a rodent and its humanized version single-chain fragments(scFv) specific for hepatocellular carcinoma (HCC) and compare these two scFves in antigen binding activity. Three vectors were used to express these two genes in different routes of fusion pathway, secrete pathway and intracellular pathway. The refolded single-chain antibodies were examined by antigen capture ELISA. Results showed that inclusion bodies were produced in all of the applied vectors despite of variation of IPTG concentration and culture temperature. Cell ELISA and binding competition inhibition indicated that the humanized single-chain Fv retained the similar affinity as its rodent counterpart. These results implied that the solubility of genetic antibodies are determined primarily by its amino acids sequence; The adopted humanization strategy in previous design made little effect on the natural conformation of complementarity-determining regions(CDR) of the parent antibody. The humanized HCC specific scFv can be further evaluated and developed as therapeutics.

Characteristics of recombinant human butyrylcholinesterase

AIM

To study the biochemical-pharmacological properties of the recombinant human butyrylcholinesterase (rhBChE) and thereby to size up the potential possibility of using it as a detoxifying agent in succinylcholine intoxication.

METHODS

CHO-dhfr cells were transfected with plasmids by electroporation. BChE activity was determined colorimetrically by 5, 5'-dithiobis-(2-nitrobenzoic acid) (DTNB) method. Antigenicity was estimated by enzyme-linked immunosorbent assay and Western blot.

RESULTS

The maximal expression amounted to 25.83 ng.h-1/10(6) cells. The rhBChE was highly similar to the native human BChE (nhBChE) in terms of its catalytic property, substrate affinity, inhibitor sensitivity, reactivation, stability, and immunoreactivity with anti-nhBChE antibodies. Mice challenged with 1.5 lethal dose of succinylcholine preincubated with rhBChE survived without any symptoms of intoxication.

CONCLUSION

The rhBChE and nhBChE exhibit similar biochemical-pharmacological features. It is of potential value in practical use.

Gene amplification and high-level expression of human pro-urokinase cDNA in Chinese hamster ovary cells

Human Pro-Urokinase (Pro-UK) is expressed in CHO-DHFR- cells at high efficiency by co-transfecting the mouse dhfr gene and Pro-UK cDNA under the control of the SV40 late promoter. After gene co-amplification, the product level could reach 2-3 micrograms/10(6) cells/24 h in the presence of 5 x 10(-6) mol/L MTX, and the levels can be further raised to 3.5-4 micrograms/10(6) cells/24 h by PMA superinduction. The copy number of Pro-UK cDNA in the genomes of host cells is about 200-300 copies/cell. The Western blot analysis shows that the recombinant Pro-UK has similar molecular weight to its natural counterpart, and also the amidolytic activity of the product is determined by S-2444 assay.

Identification of residues involved in polymorphic antibody binding epitopes on HLA-DR molecules

Based on previous studies it was predicted that amino acids 4 or 25 of the DR4 beta 1 and DR7 beta 1 chains are involved in polymorphic antibody binding epitopes on DR4 or DR7 molecules. These predictions were tested by analyzing monoclonal antibody (mAb) binding to transfectants expressing mutant DR4 beta 1 or DR7 beta 1 chains with single amino acid substitutions at positions 4 or 25. Antibody binding to transfectants expressing additional DR4/7 beta 1 hybrids was also analyzed to assess further the contributions of four segments of the DR4 beta 1 or DR7 beta 1 chains: amino acids 1-20, 21-40, 41-97, and the beta 2 domain. Single amino acid substitutions at positions 4 and 25 of the DR4 beta 1 chain or DR7 beta 1 chain eliminate binding of several mAb to DR4 or DR7 molecules, documenting that these residues are involved in antibody epitopes. However, the data with the hybrid DR4/7 beta 1 chains indicate that some of these epitopes require contributions from both segments 1-20 and 21-40 of these DR beta chains, whereas other epitopes can be generated by placing the appropriate segment in the context of the other DR beta chain. In addition, the data with other mAb indicate that their epitopes are determined primarily by sequences within the 41-97 segment or in the beta 2 domain.

Diverse locations of amino acids in HLA-DR beta chains involved in polymorphic antibody binding epitopes on DR(alpha, beta 1*0101), DR(alpha, beta 1*1101), and DR(alpha,beta 3*0202) molecules

In a previous study, we used transfectants expressing hybrid HLA-DR(beta 1*0403)/DR(beta 1*0701) chains to map sequences involved in polymorphic antibody binding epitopes on DR(alpha, beta 1*0403) or DR(alpha, beta 1*0701) molecules. Amino acids 1-40 of the beta 1 domain were found to make the major contributions to most of the antibody binding epitopes studied. To begin to localize sequences that contribute to polymorphic antibody epitopes on DR(alpha,beta 1*0101), DR(alpha,beta 1*1101) and DR(alpha,beta 3*0202) molecules, we used indirect immunofluorescence and flow cytometry to assess the binding of mAb to transfectants expressing hybrid DR(beta 1*0101)/DR(beta 1*1101) or DR(beta 1*1101)/DR(beta 3*0202) chains that divide the DR beta chain into three segments: amino acids 1-40, 41-97, and the beta 2 domain. The results indicate that amino acids 41-97 of the beta 1 domain on DR(beta 1*0101), DR(beta 1*1101), or DR(beta 3*0202) are critical in most of the epitopes, including those recognized by human antibodies MP4 and MP12, and mouse mAb GS88.2, I-LR1, 21r5, and 7.3.19.1, whereas amino acids 1-40 of DR(beta 1*1101) are critical in the epitope recognized by the MCS-7 mAb, and both segments 1-40 and 41-97 of DR(beta 1*1101) are important in the epitopes recognized by the I-LR2 and UL-52 mAbs. Based on these data and comparison of DR beta allelic protein sequences, the residues that may play critical roles in these antibody binding epitopes are predicted.

DRw11 haplotypes: continuum of DRB1 diversity augmented by unique DQ/DRw52 associations

cDNA sequencing of the first domains of DRB1, DRB3, DQA1, and DQB1 alleles was used to examine the extent of diversity in American black individuals expressing several DRw11 haplotypes. In addition to previously described DRw11 alleles, DRB1*1102 and DRB1*1103, two new DRB1 alleles, DRB1*11012 and DRB1*11042, were identified which differ from previously described alleles at the nucleic acid but not at the protein level. Gene conversion-like events have likely generated the DRw11 microvariation resulting in the merging of DRw11 with the DRw13 allele family. The DRw11 alleles are associated with various DQ alleles: DQw1 (DQw5 and DQw6), DQw7, and a serologically undefined DQ allele. This undefined DQ molecule, comprised of a DQ alpha/beta combination encoded by a DQw7 alpha gene (DQA1*0301) and a DQw2 beta gene (DQB1*0201), was previously observed in some DR7 and DR9 haplotypes. DRw11 haplotype diversity is augmented by the association of one of the DRw11 alleles with the DRw52c allele in contrast to the more common DRw11, DRw52b association. The extensive diversity exhibited by the DRw11 and DRw13 family of haplotypes coupled with their high frequency in populations of African ancestry suggest that the DRw11/w13 allele family may be very old and/or that these haplotypes carry some selective advantage.

Antigen-specific T cells with monogamous or promiscuous restriction patterns are sensitive to different HLA-DR beta chain substitutions

The contributions of the amino acids at 13 polymorphic positions in the HLA-DR7 beta 1 chain to T cell recognition of two antigenic peptides of tetanus toxin (p2 and p30) were assessed using transfectants expressing mutant DR7 beta 1 chains as APC for six toxin-specific T cell clones with two different restriction patterns: monogamous (restricted by DR7 only) or promiscuous (restricted by DR7; DR1; DR2, Dw21; and DR4, Dw4). Each of the 13 substitutions significantly decreased or eliminated the ability of the DR7 molecule to present a peptide to one or more of the T cell clones, but none of the substitutions abolished recognition by all clones. Interestingly, substitutions at positions 4 and 25, which are predicted in the class II model to be located outside the peptide binding groove, decreased the ability of the DR7 molecule to present Ag to some clones but not to others. Each of the four clones specific for the p2 peptide and the two clones specific for peptide p30 had a different reactivity pattern to the panel of DR7 beta 1 mutants, indicating that the TCR of each clone has a different view of the p2/DR7 or p30/DR7 complex. These data emphasize the complexity of the interactions of multiple residues in DR7 beta 1 chains in Ag-specific T cell recognition.