Accuracy of parent-reported ages and stages questionnaire in assessing the motor and language skills of preterm infants.

BACKGROUND: Parent-completed tools like the Ages and Stages Questionnaire Third Edition (ASQ-3) are important in developmental screening. As a screening tool, a high negative predictive value (NPV) is critical to avoid missing the diagnosis of developmental delay. This study evaluated the NPV and accuracy of the ASQ-3 in assessing the development of preterm infants. METHODS: Infants born at <32 weeks and/or <1250 grams, presenting to the Neonatal Neurodevelopmental Clinic at the Singapore General Hospital for follow-up from January 2014 to June 2017, at 6, 12, and 18 months corrected age, were included. The ASQ-3 and standardized tests - Peabody Developmental Motor Scale-Second Edition (PDMS-2) and Preschool Language Scale, Fourth Edition UK (PLS-4 UK) - were administered. ASQ-3 gross motor and fine motor scores were compared to PDMS-2 at 6 and 12 months, and ASQ-3 communication scores to PLS-4 UK at 18 months. RESULTS: At 6 months (n = 145), NPV for gross motor and fine motor were 96.4% (accuracy 80.0%) and 95.4% (accuracy 77.2%) respectively. At 12 months (n = 127), NPV for gross motor and fine motor were 88.9% (accuracy 79.8%) and 82.8% (accuracy 74.0%) respectively. At 18 months (n = 113), NPV for language was 56.9% (accuracy 63.7%). CONCLUSIONS: The ASQ-3 showed high NPV and accuracy in screening gross motor and fine motor skills at 6 and 12 months, but not in screening language skills at 18 months. Judicious use of the ASQ-3 may allow for more effective utilization of resources.

Hand-touch contact assessment of high-touch and mutual-touch surfaces among healthcare workers, patients, and visitors.

BACKGROUND: Unlike direct contact with patients' body, hand hygiene practice is often neglected by healthcare workers (HCWs) and visitors after contact with patients' environment. Contact with hospital environmental items may increase risk of pathogen transmission. AIM: To enumerate the number of hand-touch contacts by patients, HCWs and visitors with any hospital environmental items. METHODS: All contact-episodes between person and item were recorded by direct observation in a six-bed cubicle of acute wards for 33 working days. High-touch and mutual-touch items with high contact frequencies by HCWs, patients, and visitors were analysed. FINDINGS: In total, 1107 person-episodes with 6144 contact-episodes were observed in 66 observation hours (average: 16.8 person-episodes and 93.1 contact-episodes per hour). Eight of the top 10 high-touch items, including bedside rails, bedside tables, patients' bodies, patients' files, linen, bed curtains, bed frames, and lockers were mutually touched by HCWs, patients, and visitors. Bedside rails topped the list with 13.6 contact-episodes per hour (mean), followed by bedside tables (12.3 contact-episodes per hour). Using patients' body contacts as a reference, it was found that medical staff and nursing staff contacted bedside tables [rate ratio (RR): 1.741, 1.427, respectively] and patients' files (RR: 1.358, 1.324, respectively) more than patients' bodies, and nursing staff also contacted bedside rails (RR: 1.490) more than patients' bodies. CONCLUSION: Patients' surroundings may be links in the transmission of nosocomial infections because many are frequently touched and mutually contacted by HCWs, patients, and visitors. Therefore, the focus of hand hygiene education, environmental disinfection, and other system changes should be enhanced with respect to high-touch and mutual-touch items.

Coordinated upper limb training assisted with an electromyography (EMG)-driven hand robot after stroke.

An electromyography (EMG)-driven hand robot had been developed for post-stroke rehabilitation training. The effectiveness of the hand robot assisted whole upper limb training on muscular coordination was investigated on persons with chronic stroke (n=10) in this work. All subjects attended a 20-session training (3-5 times/week) by using the hand robot to practice object grasp/release and arm transportation tasks. Improvements were found in the muscle co-ordination between the antagonist muscle pair (flexor digitorum and extensor digitorum) as measured by muscle co-contractions in EMG signals; and also in the reduction of excessive muscle activities in the biceps brachii. Reduced spasticity in the fingers was also observed as measured by the Modified Ashworth Score.

The effects of post-stroke upper-limb training with an electromyography (EMG)-driven hand robot.

Loss of hand function and finger dexterity are main disabilities in the upper limb after stroke. An electromyography (EMG)-driven hand robot had been developed for post-stroke rehabilitation training. The effectiveness of the hand robot assisted whole upper limb training was investigated on persons with chronic stroke (n=10) in this work. All subjects attended a 20-session training (3-5times/week) by using the hand robot to practice object grasp/release and arm transportation tasks. Significant motor improvements were observed in the Fugl-Meyer hand/wrist and shoulder/elbow scores (p<0.05), and also in the Action Research Arm Test and Wolf Motor Function Test (p<0.05). Significant reduction in spasticity of the fingers as was measured by the Modified Ashworth Score (p<0.05). The training improved the muscle co-ordination between the antagonist muscle pair (flexor digitorum (FD) and extensor digitorum (ED)), associated with a significant reduction in the ED EMG level (p<0.05) and a significant decrease of ED and FD co-contraction during the training (p<0.05); the excessive muscle activities in the biceps brachii were also reduced significantly after the training (p<0.05).

The effects of electromechanical wrist robot assistive system with neuromuscular electrical stimulation for stroke rehabilitation.

An electromyography (EMG)-driven electromechanical robot system integrated with neuromuscular electrical stimulation (NMES) was developed for wrist training after stroke. The performance of the system in assisting wrist flexion/extension tracking was evaluated on five chronic stroke subjects, when the system provided five different schemes with or without NMES and robot assistance. The tracking performances were measured by range of motion (ROM) of the wrist and root mean squared error (RMSE). The performance is better when both NMES and robot assisted in the tracking than those with either NMES or robot only (P<0.05). The muscle co-contractions in the upper limb measured by EMG were reduced when NMES provided assistance (P<0.05). All subjects also attended a 20-session wrist training for evaluating the training effects (3-5 times/week). The results showed improvements on the voluntary motor functions in the hand, wrist and elbow functions after the training, as indicated by the clinical scores of Fugl-Meyer Assessment, Action Research Arm Test, Wolf Motor Function Test; and also showed reduced spasticity in the wrist and the elbow as measured by the Modified Ashworth Score of each subject. After the training, the co-contractions were reduced between the flexor carpi radialis and extensor carpi radialis, and between the biceps brachii and triceps brachii. Assistance from the robot helped improve the movement accuracy; and the NMES helped increase the muscle activation for the wrist joint and suppress the excessive muscular activities from the elbow joint. The NMES-robot assisted wrist training could improve the hand, wrist, and elbow functions.

Studying the transmission dynamics of meticillin-resistant Staphylococcus aureus in Hong Kong using spa typing.

This study investigated the transmission dynamics of meticillin-resistant Staphylococcus aureus (MRSA) in a tertiary referral surgical unit with 300 beds. All adult patients were actively screened for MRSA by culture at hospital admission and twice weekly thereafter during hospitalisation from 1 October to 31 December 2008. The colonisation pressure per 1000 patient-days and the incidence density of nosocomial MRSA transmission per 1000 colonisation-days were calculated for the different spa types of MRSA. In total, 6619 nasal swabs were obtained from 2289 patients. One-hundred and forty-eight (7%) patients had MRSA in nasal swabs at admission screening, of which 68/148 (46%) were residents of elderly care homes. Fifty-two of 2141 (2%) patients had conversion of nasal MRSA carriage status from negative to positive during hospitalisation. Among the 200 patients with MRSA, spa types t1081 and t037 were found in 99 (50%) and 30 (15%) patients, respectively. The colonisation pressure per 1000 patient-days was 40.9 for t0181, 22.2 for t037 and 26.3 for the less common spa types. The incidence densities of nosocomial MRSA transmission per 1000 colonisation-days were significantly higher for t1081 (28.5 vs 4.0, P<0.01) and t037 (21.5 vs 4.0, P=0.03) compared with the less common spa types. Proactive screening of MRSA in patients from elderly care homes and targeted isolation of these patients, especially those carrying spa types with high transmissibility, are important for the control of MRSA in hospitals.

Post-stroke wrist rehabilitation assisted with an intention-driven functional electrical stimulation (FES)-robot system.

In this work, a novel FES-robot system was developed for wrist rehabilitation training after stroke. The FES-robot system could be continuously controlled by electromyography (EMG) from the residual wrist muscles to facilitate wrist flexion and extension tracking tasks on a horizontal plane by providing assistance from both FES and robot parts. The system performance with five different assistive combinations from the FES and robot parts was evaluated by subjects with chronic stroke (n=5). The results suggested that the assistance from the robot part mainly improved the movement accuracy in the tracking tasks; and the assistance from the FES part mainly suppressed the excessive muscular activities from the elbow joint. The best combination was when the assistances from FES and robot was 1:1, and the results showed better wrist tracking performance with less muscle co-contraction from the elbow joint.

Effectiveness of functional electrical stimulation (FES)-robot assisted wrist training on persons after stroke.

A functional electrical stimulation (FES)-robot system controlled by subjects' motor intention was developed in our previous study. The effectiveness of the FES-robot on wrist training was investigated in this work. Five hemiplegic subjects with chronic stroke were recruited for an FES-robot assisted wrist training with 20 sessions. After the training, motor improvements were found in the wrist and fingers, represented by significant increase (P < 0.05) in clinical scores of the Fugl-Meyer Assessment (FMA), the Action Research Arm Test (ARAT), and the Modified Ashworth Score (MAS). Muscle coordination in the upper limb was also improved during the training as assessed by electromyography. The increased ARAT scores suggested improved upper limb motor functions, especially in the hand and fingers, compared to no improvement in previous study with only interactive robot-assisted wrist training without FES.

An intention driven hand functions task training robotic system.

A novel design of a hand functions task training robotic system was developed for the stroke rehabilitation. It detects the intention of hand opening or hand closing from the stroke person using the electromyography (EMG) signals measured from the hemiplegic side. This training system consists of an embedded controller and a robotic hand module. Each hand robot has 5 individual finger assemblies capable to drive 2 degrees of freedom (DOFs) of each finger at the same time. Powered by the linear actuator, the finger assembly achieves 55 degree range of motion (ROM) at the metacarpophalangeal (MCP) joint and 65 degree range of motion (ROM) at the proximal interphalangeal (PIP) joint. Each finger assembly can also be adjusted to fit for different finger length. With this task training system, stroke subject can open and close their impaired hand using their own intention to carry out some of the daily living tasks.

Combined functional electrical stimulation (FES) and robotic system for wrist rehabiliation after stroke.

Functional electrical stimulation (FES) and rehabilitation robots are techniques used to assist in post-stroke rehabilitation. However, FES and rehabilitation robots are still separate systems currently; and their combined training effects on persons after experiencing a stroke have not been well studied yet. In this work, a new combined FES-robot system driven by user's voluntary intention was developed for wrist joint training after stroke. The performance of the FES-robot assisted wrist tracking was evaluated on five subjects with chronic stroke. With simultaneous assistance from both the FES and robot parts of the system, the motion accuracy was improved and excessive activation in elbow flexor was reduced during wrist tracking.

Parental knowledge of prematurity and related issues.

INTRODUCTION: Current medical advances have increased the survival rate of the premature infant with its complications. Risk factors for prematurity include maternal diabetes mellitus, hypertension, smoking and alcohol intake. METHODS: A true/false questionnaire survey focusing on risk factors, outcomes/follow-up and costs was administered to adults attending a parenting-related public forum. One point was awarded per correct answer. Entire prematurity knowledge and section T-scores were calculated, (a pass mark was defined as at least 50 percent for each T-score). Missing answers and affected T-scores were considered invalid. RESULTS: There were 81 respondents: predominantly within 21-40 years of age, Chinese, female, public-housing dwellers, first-time parents-to-be and with graduate or higher-level qualifications. A pass in entire and prematurity knowledge T-scores was achieved in 69 percent (median 13 [range 3-21]) and 62 percent (median 12 [range 0-19]) respectively. A pass in section T-scores on risk factors, outcomes and costs was achieved in 62, 53 and 75 percent, respectively. Awareness of risks and outcomes did not correlate with awareness of costs. Logistic regression did not reveal any factors contributing to a pass or higher T-scores. CONCLUSION: Although the majority achieved a pass in all T-scores, general knowledge among this childbearing group was deemed inadequate by the median scores. As survival improves, awareness of prematurity and its risks has to be improved, with a target to reduce the incidence of prematurity and to support those infants who require resource-intensive follow-up.

EphB2 and EphA4 receptors regulate formation of the principal inter-hemispheric tracts of the mammalian forebrain.

Previously, we have demonstrated that EphB2 activity is required for proper development of the posterior branch of the anterior commissure (ACpp) within the mammalian forebrain. In the present study, using magnetic resonance imaging (MRI), immunohistochemistry, and in vivo stereotactic fluorescence tracing of EphB2, B3, A4 and combinatorial Eph receptor mutants, we have developed a detailed three-dimensional model of how EphB-class receptors interact to regulate commissural formation within the forebrain. The results demonstrate that EphB2 and EphA4 each regulate distinct aspects of axon guidance within the ACpp. Specifically, while EphB2 is required to retard ACpp axons from projecting aberrantly into the ventral forebrain, EphA4 is required to restrict axons from entering the anterior branch of the anterior commissure (ACpa). Together, EphB2 and EphA4 act synergistically to prevent a subpopulation of axons within the anterior branch of the AC from mis-projecting caudally. Analysis of EphA4 null mice using high resolution MRI reveals for the first time that, in addition to errors in midline guidance, loss of EphA4 results in aberrant lateral and ventral displacement of the ACpa tract. In addition, tracing studies in alpha-chimerin null mice reveal that EphA4-mediated effects are not regulated through this pathway. Taken together, the results demonstrate that each of the principal guidance decisions within both anterior and posterior tracts of the anterior commissure can be accounted for by the individual and combinatorial actions of EphB2/A4 receptors.

Development of a high resolution three-dimensional surgical atlas of the murine head for strains 129S1/SvImJ and C57Bl/6J using magnetic resonance imaging and micro-computed tomography.

The mouse has emerged as a major experimental model system for examining the functional properties of the mammalian CNS; both during development and following CNS injury. Histologic procedures currently used to determine the relative position of structures within the CNS are presently limited in their ability to take full advantage of this system for surgical and morphometric procedures. We present here the first three-dimensional interactive digital atlas of the murine brain and skull for two genetically important strains of mice; 129S1/SvImJ and C57Bl/6J. The final resolution of these digital atlases is 54 micro m(3). These representations of the murine brain and skull, in conjunction with our development of a new, more dynamic master coordinate system, provide improved accuracy with respect to targeting CNS structures during surgery compared with previous systems. The interactive three-dimensional nature of these atlases also provide users with stereotactic information necessary to perform accurate "off-axis" surgical procedures, as is commonly required for experiments such as in vivo micro-electroporation. In addition, three-dimensional analysis of the brain and skull shape in C57Bl, 129Sv, CD1, and additional murine strains, suggests that a stereotactic coordinate system based upon the lambda and rostral confluence of the sinuses at the sagittal midline, provides improved accuracy compared with the traditional lambda-bregma landmark system. These findings demonstrate the utility of developing highly accurate and robust three-dimensional representations of the murine brain and skull, in which experimental outputs can be directly compared using a unified coordinate system. The aim of these studies is to enhance comparative morphometric analyses and stereotactic surgical procedures in mice.

Sub-part-per-billion analysis of aqueous lead colloids by ArF laser induced atomic fluorescence.

Highly sensitive analysis of aqueous lead carbonate colloids was demonstrated by two-pulse laser-induced atomic fluorescence. The first laser pulse at 1064 nm ablated the sample solution to create an expanding plume. The colloids, being heavier, trailed behind and became concentrated. They were then intercepted by an ArF laser pulse that induced prompt atomic fluorescence at 405.8 nm from the lead atoms. The detection limit for lead was 0.24 ppb. Tap water was analyzed, and lead emissions were clearly observed. Time-resolved spectroscopy revealed that the efficient 193-nm excitation of the analytes was more universal than expected. That was confirmed by the successful application of the technique to colloids and alloys other than lead.

General practitioners' knowledge on childhood developmental and behavioural disorders.

INTRODUCTION: Childhood developmental and behavioural disorders are increasingly being recognised, with high demands for earlier diagnosis and intervention. In Singapore, referrals to the Child Development Unit, KK Women's and Children's Hospital, originate mainly from primary health care practitioners, who therefore should have adequate baseline knowledge of normal development as well as common developmental and behavioural disorders. METHODOLOGY: A pilot study, using a questionnaire survey, was conducted, with the aim of assessing existing knowledge in childhood developmental and behavioural paediatrics amongst a cohort of general practitioners (GPs) in Singapore. True/False questions on normal development as well as developmental disorders such as autistic spectrum disorder (ASD), attention deficit/hyperactivity disorder (ADHD) and learning disability, were structured. These disorders were selected because of their relatively higher prevalence. RESULTS: A total of 48 GPs were surveyed, representing 2% of non-specialists practising in the private sector. The median total score (T-score) was 9 (range 6 to 13) of a possible 14. Only just over a-third of the group achieved the pass rate (defined arbitrarily as 75%) for T-score, with two-thirds replying correctly to all questions on normal development. Scores for factual ASD/ADHD questions were also not ideal, with some myths being believed as truths. CONCLUSION: The scores reflect knowledge and educational deficits in developmental paediatric medicine amongst the study cohort. Expected to provide holistic care and counselling, these GPs are currently insufficiently equipped with the necessary knowledge and skills to support families of special-needs children. Education and training programmes in this aspect of paediatric medicine are clearly needed, through the organisation of CME lectures and incorporation of various developmental topics into the training curriculum. This will enable early identification and diagnosis of childhood developmental and behavioural disorders, which will in turn allow greater optimisation of potential and functionality in these special-needs children.

Application of classification tree and neural network algorithms to the identification of serological liver marker profiles for the diagnosis of hepatocellular carcinoma.

OBJECTIVE: Although many attempts have been made to identify tumour-specific alpha-fetoprotein (AFP) glycoforms or other serological markers for the diagnosis of hepatocellular carcinoma (HCC), none of the available markers has, so far, shown satisfactory sensitivity and specificity. Here we aimed to apply classification tree and neural network algorithms to interpret the levels of multiple serological liver markers to improve overall specificity and sensitivity, particularly with a view to discriminating between liver cirrhosis with and without HCC. METHODS: We developed classification trees and neural networks that identified serological liver marker profiles comprising AFP, alpha1-antitrypsin (A1AT), alpha2-macroglobulin (A2MG), thyroxine-binding globulin (TBG), transferrin and albumin as well as sex and age, which might permit the diagnosis of HCC. Data were collected from 65 HCC patients, 51 patients with liver cirrhosis alone (LC) and 51 normal healthy subjects. RESULTS: The generated classification trees and neural networks showed similar diagnostic values in differentiating HCC from LC. The classification trees identified AFP, A1AT and albumin as the most important classification parameters, whereas the neural networks identified A2MG, AFP, A1AT and albumin as the predominant factors. The classification logic of the classification trees indicated that more HCC cases could be identified among cases with slightly elevated AFP levels by using the serum levels of A1AT and albumin. The neural networks were also useful for the identification of the HCC cases when the AFP levels were below 500 ng/ml (p < 0.005). The neural networks could identify HCC cases with AFP levels within the normal range, but the classification trees could not. By combining the conventional AFP test and the neural networks, the overall diagnostic sensitivity for HCC was significantly increased from 60.0 to 73.8% (p < 0.05) while maintaining a high specificity (88.2%). The sensitivities for tumors of different sizes were similar. CONCLUSION: The neural network algorithm appeared to be more powerful than the classification tree algorithm in the identification of the distinctive serological liver marker profiles for the diagnosis of the HCC subgroup without significant elevation in serum AFP levels. By incorporating serological levels of other liver markers and including data from a large number of patients and control subjects, it should prove possible to develop a versatile neural network for early diagnosis of HCC.

Increased survival of mesothelial cells from the peritoneum in peritoneal dialysis fluid.

Peritonitis remains the most important factor in patient morbidity and technical failure associated with continuous ambulatory peritoneal dialysis (CAPD). In vitro examination of bacterial infection of cultured human peritoneal mesothelial cells (HPMC) is an attractive approach to the study of peritonitis in CAPD, yet there are few reports on this subject. Previous studies have shown two limitations: (i) cell cultures of HPMC lasted for days only when incubated in culture medium and (ii) short-term studies of <30 min were done in HPMC when incubated with peritoneal dialysis fluid (PDF). Human peritoneal mesothelial cells, maintained in a conventional single chamber culture system with PDF alone, were unable to survive more than 40 min. The present study was designed to prolong the viability of HPMC cultured in PDF, with the object of using cells under different conditions, such as that of simulating CAPD. HPMC were cultured using plastic microtiter plates, where they were grown to confluence and growth was arrested. PDF containing different concentrations of NaHCO3and human serum albumin was added. Cell viability after exposure for up to 24 h was measured by trypan blue, Cell Death Detection ELISA and Annex-V flow cytometry. The data confirmed the 'toxic' effect of PDF, with cell viability being <40% after 2 h incubation in 4.25% glucose in PDF. However, the survival time of HPMC increased significantly in 4.25% glucose PDF at a physiological pH and even further after the addition of human albumin. These experimental conditions simulating CAPD may allow future in vitro studies of mesothelial physiology and peritonitis related to CAPD treatment.

Use of the sinus P wave in diagnosing electrocardiographic limb lead misplacement not involving the right leg (ground) lead.

No general approach has been established for the diagnoses of the various types of electrocardiograms of limb lead misplacement not involving the right leg (ground) lead. We have developed a 3-step algorithm for such differential diagnosis that can be applied without having to rely on the comparison with a reference electrocardiogram. It is based on the observation that the frontal plane sinus P vector loop is almost invariably inscribed counterclockwise. The 5 types of electrocardiograms of limb lead misplacement can be differentiated according to the P wave axis, the location of the lead aVR in the electrocardiogram, and specifically any apparent reversal of the direction of inscription of the frontal plane P vector loop due to lead misplacement. Characteristic limb lead P wave patterns provide 6 signs capable of inferring from the electrocardiogram alone the direction of inscription about 94% of the time. P wave axis itself is diagnostic in an additional 4%.

Preoperative systemic chemoimmunotherapy and sequential resection for unresectable hepatocellular carcinoma.

OBJECTIVE: To examine the surgical and pathologic findings of 15 patients who had initially unresectable hepatocellular carcinoma (HCC) and received preoperative systemic chemoimmunotherapy and sequential resection. SUMMARY BACKGROUND DATA: More than 80% of patients with HCC present for treatment at an unresectable stage. Conventional treatment has produced a low tumor response rate in this group of patients. Recently, new systemic chemoimmunotherapy has been found to be effective and able to make previously unresectable HCC resectable. Sequential resection after response to chemoimmunotherapy could therefore induce complete clinical remission. METHODS: From July 1996 to February 1999, 150 patients with unresectable HCC were treated with systemic chemoimmunotherapy consisting of cisplatin, alpha-interferon, doxorubicin, and 5-fluorouracil for a maximum of six cycles. The residual tumors were reassessed for resectability after treatment aiming at complete remission in the patients after combined modality treatment. Twenty-seven patients had a more than 50% regression in tumor size (2 complete remissions, 25 partial remissions). Fifteen patients had resectable disease after treatment, and all underwent sequential resection with curative intent. Treatment outcome and the surgical and pathologic features of these 15 patients were studied. RESULTS: Fifteen of 150 patients responded to chemoimmunotherapy and underwent sequential resection. They were considered to have unresectable disease as a result of extensive local disease (with and without major vascular involvement) in 10 patients and the presence of extrahepatic or metastatic disease in 5 patients. All patients except two were hepatitis B carriers. Surgical resection of the residual lesion after chemoimmunotherapy was successful for all patients. Eight of the patients had complete pathologic remission. The rest had minimal residual disease (<5%) only. All 15 patients entered complete clinical remission after surgery. Thirteen patients were still alive as of this writing and two had died of recurrent disease. The 1-, 2-, and 3-year survival rates were 100%, 100%, and 53%, respectively. The mean follow-up period was 27 months (range 15-37). Neither the median disease-free nor overall survival had been reached. Ten patients remained in complete remission as of this writing. CONCLUSION: Combined modalities with systemic chemoimmunotherapy and surgical resection can achieve complete clinical remission and long-term control of disease in patients with unresectable HCC.

Transferrin but not albumin mediates stimulation of complement C3 biosynthesis in human proximal tubular epithelial cells.

Complement is increasingly implicated in the pathogenesis of progressive renal disease resulting from persistent proteinuria. We have previously shown that apical serum proteins stimulate C3 in cultured human proximal tubular epithelial cells (PTECs), and that the stimulant is a nonalbumin compound of 30 to 100 kd. We postulated in this study that transferrin and apotransferrin, also important components of proteinuric urine in this molecular-weight range, might be the culprit. Human PTECs were obtained by differential sieving of renal cortical tissue from the normal pole of tumor nephrectomy specimens and characterized to be predominantly of proximal tubular origin. Complement C3 messenger RNA (mRNA) expression was analyzed in confluent growth-arrested PTEC monolayers in media containing different concentrations (2.5 to 20 mg/mL) of transferrin by reverse transcription and polymerase chain reaction. Pure human albumin was used as a control protein. C3 protein secretion was detected and quantified by a sandwich enzyme-linked immunosorbent assay on cell culture supernatants after distinct time points. Transferrin enhanced the rate of C3 secretion in a dose-dependent manner, reaching maximal stimulation at doses of 10 mg/mL. Selected experiments using the Transwell technique showed that C3 release was predominantly apical in the resting state. The addition of 10 mg/mL of transferrin apically but not basolaterally stimulated both apical and basolateral C3 secretion and increased the basolateral-apical ratio of C3 secretion from 0.45 +/- 0.16 to 0.93 +/- 0.24 (P: < 0.02). Constitutive C3 mRNA expression was upregulated by transferrin in a time- and dose-dependent fashion, reaching a peak after 24 hours. A similar degree of C3 upregulation was reproduced when iron-poor transferrin, apotransferrin, was used instead. These results indicate that C3 synthesis in PTECs is upregulated by transferrin, for which protein rather than iron moiety may account for the observed effects. These findings provide evidence linking proteinuria with overexpression of tubular complement.