Diabetic ketoacidosis in children with new-onset type 1 diabetes mellitus: demographics, risk factors and outcome: an 11 year review in Hong Kong.

OBJECTIVES: Diabetic ketoacidosis (DKA) is a life-threatening complication of type 1 diabetes (T1D). The aim of this study is to analyze the incidence, clinical characteristics, management and outcome of children presenting with DKA in new-onset T1D from 2008 to 2018 in Hong Kong. METHODS: Data was extracted from the Hong Kong Childhood Diabetes Registry. All subjects less than 18 years with newly diagnosed T1D from 1 January 2008 to 31 December 2018 managed in the public hospitals were included. Information on demographics, laboratory parameters, DKA-related complications and management were analyzed. RESULTS: In the study period, there were 556 children with newly diagnosed T1D in our registry and 43.3% presented with DKA. The crude incidence rate of new-onset T1D with DKA was 1.79 per 100,000 persons/year (CI: 1.56-2.04). Subjects presenting with DKA were younger (9.5 ± 4.5 vs. 10.5 ± 4.4, p=0.01) and had shorter duration of symptoms (4.2 ± 5.9 days vs. 10.6 ± 17.1 days, p<0.01). Regarding management, up to 12.4% were given insulin boluses and 82.6% were started on insulin infusion 1 h after fluid resuscitation. The rate of cerebral edema was 0.8% and there was no mortality. CONCLUSIONS: Younger age and shorter duration of symptoms were associated with DKA in new-onset T1D. Despite availability of international guidelines, there was inconsistency in acute DKA management. These call for a need to raise public awareness on childhood diabetes as well as standardization of practice in management of pediatric DKA in Hong Kong.

Epidemiology and phenotypes of diabetes in children and adolescents in non-European-origin populations in or from Western Pacific region.

BACKGROUND: Type 1 diabetes (T1D) incidence varies substantially between countries/ territories, with most studies indicating increasing incidence. In Western Pacific region (WPR), reported rates are much lower than European-origin populations. In contrast, there are reports of substantial numbers of young people with type 2 diabetes (T2D). A deeper understanding of T1D and T2D in the WPR may illuminate factors important in pathogenesis of these conditions. Furthermore, with varying resources and funding for diabetes treatment in this region, there is a need to more clearly determine the current burden of disease and also any gaps in knowledge. AIM: To compile and summarise published epidemiologic and phenotypic data on childhood diabetes in non-European populations in and from WPR. METHODS: Research articles were systematically searched from PubMed (MEDLINE), Embase, Cochrane library, and gray literature. Primary outcome measures were incidence and prevalence, with secondary measures including phenotypic descriptions of diabetes, including diabetes type categorization, presence of diabetic ketoacidosis (DKA) at onset, autoantibody positivity, C-peptide levels, and human leucocyte antigen phenotype. Extracted data were collected using a customized template. Three hundred and thirty relevant records were identified from 16 countries/territories, with analysis conducted on 265 (80.3%) records published from the year 2000. RESULTS: T1D incidence ranged from < 1-7.3/100000 individuals/year, rates were highest in emigrant/ mixed populations and lowest in South-East Asia, with most countries/territories (71.4%) having no data since 1999. Incidence was increasing in all six countries/territories with data (annual increases 0.5%-14.2%, highest in China). Peak age-of-onset was 10-14 years, with a female case excess. Rate of DKA at onset varied from 19.3%-70%. Pancreatic autoantibodies at diagnosis were similar to European-origin populations, with glutamic acid decarboxylase-65 autoantibody frequency of 44.1%-64.5%, insulinoma-associated 2 autoantibody 43.5%-70.7%, and zinc transporter-8 autoantibody frequency 54.3% (one study). Fulminant T1D also occurs. T2D was not uncommon, with incidence in Japan and one Chinese study exceeding T1D rates. Monogenic forms also occurred in a number of countries. CONCLUSION: T1D is less common, but generally has a classic phenotype. Some countries/ territories have rapidly increasing incidence. T2D is relatively common. Registries and studies are needed to fill many information gaps.

Incidence and clinical characteristics of pediatric-onset type 2 diabetes in Hong Kong: The Hong Kong childhood diabetes registry 2008 to 2017.

OBJECTIVE: With increasing prevalence of childhood obesity worldwide, the incidence of pediatric-onset type 2 diabetes (T2D) is also increasing in many countries. We aim to analyze the time trend and incidence of T2D in children in Hong Kong from 2008 to 2017, and to characterize clinical characteristics at diagnosis. METHODS: Data were retrieved from the Hong Kong Childhood Diabetes Registry. All children with T2D diagnosed at the age of less than 18 years from January 1, 2008 to December 31, 2017 and managed in the public health care system were included in this study. RESULTS: In the incident years of 2008-2017 period, 391 children were diagnosed with T2D. The crude incidence rate was 3.42 per 100,000 persons/year [95% confidence interval (CI) 3.08-3.76], which was much higher than that in last registry of 1.27 per 100,000 persons/year in 1997-2007 (P < 0.001).Most children (76%) were asymptomatic and were diagnosed by routine screening. At presentation, a significant proportion presented with co-morbidities including fatty liver (37.9%), dyslipidaemia (35.3%), hypertension (22.5%), and microalbuminuria (12.8%). CONCLUSIONS: The incidence of T2D in children has increased significantly in Hong Kong. Most of them were asymptomatic and picked up on routine health screening. Yet, comorbidities were commonly identified at diagnosis.

A Multicenter Survey of Type I Diabetes Mellitus in Chinese Children.

Purpose: To investigate the features and treatment status of children with type 1 diabetes mellitus (T1DM) in China. Methods: We recruited patients <14 years of age with T1DM from 33 medical centers in 25 major cities of China between January 2012 and March 2015. All patients completed a questionnaire that was conducted by their pediatric endocrinologists at all centers. Results: A total of 1,603 children (755 males and 848 females) with T1DM participated in this survey. Of these, 834 (52.03%) of the patients exhibited diabetic ketoacidosis (DKA) at onset, while 769 patients (47.97%) did not exhibit DKA (non-DKA) at onset. There was a higher proportion of females (55.71%) in the cohort of patients exhibiting DKA at onset than in the non-DKA cohort (49.33%). The mean age of patients exhibiting DKA at presentation was 7.12 ± 0.14 years; this was significantly younger than that in non-DKA group (7.79 ± 0.15 years; P < 0.005). The frequency of DKA in 3 years old, 3-7 years old, and 7 years old or more was 77.21%, 26.17%, and 37.62%, respectively. Upon initial diagnosis, 29.4%, 15.2% and 11.8% of patients showed positivity for glutamic acid decarboxylase antibody (GADA), Insulin autoantibodies (IAA), or islet cell antibody (ICA), respectively. During six months follow-up, 244 patients (15.21%) reported receiving insulin pump therapy, and more than 60% of patients monitored their blood glucose levels less than 35 times per week. Although the majority of patients had no problems with obtaining insulin, 4.74% of the children surveyed were not able to receive insulin due to financial reasons, a shortage of insulin preparations, or the failure of the parents or guardians to acquire the appropriate medicine. Conclusion: DKA is more common in very young children. Treatment and follow-up of T1DM in China still face very serious challenges.

Recommendations for the Diagnosis, Prevention, and Control of Coronavirus Disease-19 in Children-The Chinese Perspectives.

Ever since SARS-CoV-2 began infecting people by the end of 2019, of whom some developed severe pneumonia (about 5%), which could be fatal (case fatality ~3.5%), the extent and speed of the COVID-19 outbreak has been phenomenal. Within 2.5 months (by March 18, 2020) over 191,127 COVID-19 patients have been identified in 161 countries. By then, over 700 pediatric patients were confirmed to have COVID-19 in China, with only about 58 diagnosed elsewhere. By now, there are thousands of children and adolescents infected. Chinese pediatricians would like to share their experience on how these patients were managed in China and the key recommendations that had guided them in meeting the evolving challenges. A group of experts were summoned by the Chinese Pediatric Society and Editorial Board of Chinese Journal of Pediatrics to extract informative data from a survey on confirmed COVID-19 pediatric patients in China. Consensus on diagnosis, management, and prevention of pediatric COVID-19 were drawn up based on the analysis of such data plus insights gained from the past SARS and MERS coronavirus outbreaks. Relevant cumulating experiences from physicians managing adult patients, expedited reports on clinical and scientific COVID-19 and SARS-CoV-2 data, and the National Health Committee guidelines on COVID-19 management were integrated into this proposal.

Increasing incidence of type 1 diabetes among Hong Kong children and adolescents: The Hong Kong Childhood Diabetes Registry 2008 to 2017.

OBJECTIVE: The incidence of childhood-onset type 1 diabetes (T1D) has been reported to be rising but there is also evidence that it has been attenuated in recent years. We described the time trends and the incidence of T1D in children in Hong Kong from 2008 to 2017 and compared with the previous local registry in 1997 to 2007. METHODS: Data were extracted from the Hong Kong Childhood Diabetes Registry, which was established in 2016. It consists of a retrospective registry (including all childhood diabetes diagnosed in 2008 to 2015) and a prospective registry (including all T1D children diagnosed from 2016 onwards). All T1D children diagnosed at the age of less than 18 years from 1 January 2008 to 31 December 2017 and managed in the public system were included in this study. RESULTS: For the incident years in the 2008 to 2017 period, a total of 498 children with T1D was identified. The crude incidence rate was 4.3 per 100 000 person/year (95% confidence interval 3.96-4.72), which was much higher than the last registry of 2.2 per 100 000 persons/year. Using general linear model, the increment is statistically significant (P = .02). When compared to the last registry, the rate of increment had attenuated, with annual increment in crude incidence in the two periods for T1D <15 years changing from 4.3% to 3.5% (P = .02). CONCLUSIONS: The incidence of T1D children increased significantly in the past two decades in Hong Kong, but the rate of increase had attenuated in recent years.

Diagnosis, Genetics, and Therapy of Short Stature in Children: A Growth Hormone Research Society International Perspective.

The Growth Hormone Research Society (GRS) convened a Workshop in March 2019 to evaluate the diagnosis and therapy of short stature in children. Forty-six international experts participated at the invitation of GRS including clinicians, basic scientists, and representatives from regulatory agencies and the pharmaceutical industry. Following plenary presentations addressing the current diagnosis and therapy of short stature in children, breakout groups discussed questions produced in advance by the planning committee and reconvened to share the group reports. A writing team assembled one document that was subsequently discussed and revised by participants. Participants from regulatory agencies and pharmaceutical companies were not part of the writing process. Short stature is the most common reason for referral to the pediatric endocrinologist. History, physical examination, and auxology remain the most important methods for understanding the reasons for the short stature. While some long-standing topics of controversy continue to generate debate, including in whom, and how, to perform and interpret growth hormone stimulation tests, new research areas are changing the clinical landscape, such as the genetics of short stature, selection of patients for genetic testing, and interpretation of genetic tests in the clinical setting. What dose of growth hormone to start, how to adjust the dose, and how to identify and manage a suboptimal response are still topics to debate. Additional areas that are expected to transform the growth field include the development of long-acting growth hormone preparations and other new therapeutics and diagnostics that may increase adult height or aid in the diagnosis of growth hormone deficiency.

Associations between arterial structure and function and serum levels of liver enzymes in obese adolescents.

AIM: To determine the structural and functional alterations of systemic arteries in obese adolescents and their relationships with adiposity, metabolic and lipid profile, and serum liver enzyme levels. METHODS: Carotid intima-media thickness (IMT), carotid stiffness index, and brachial-ankle pulse wave velocity (baPWV) were measured in 56 obese adolescents and 58 lean controls. Obese adolescents had additional liver ultrasound and determination of fasting blood indices of glucose metabolism and lipid profile, and serum levels of liver enzymes. RESULTS: Carotid IMT (P < 0.0001), carotid stiffness index (P < 0.0001) and baPWV (P = 0.001) were significantly greater in obese than control subjects. Thirty-seven (66%) obese subjects had fatty liver changes and their aspartate aminotransferase, alanine aminotransferase (ALT), alkaline phosphatase, and gamma-glutamyl transferase levels were significantly higher than those without (all P < 0.05). Univariate analyses showed positive correlations between serum ALT (r = 0.29, P = 0.03) and alkaline phosphatase (r = 0.28, P = 0.04) levels and carotid IMT, aspartate aminotransferase level and carotid stiffness (r = 0.41, P = 0.002), and gamma-glutamyl transferase level and baPWV (r = 0.34, P = 0.02) in obese subjects. Multivariate linear regression revealed serum ALT level (ß = 0.02, P = 0.006) as an independent correlate of carotid stiffness. CONCLUSION: Obese adolescents have increased carotid IMT and stiffness, which are associated positively with serum liver enzyme levels.

The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.

OBJECTIVE: Lipodystrophy syndromes are extremely rare disorders of deficient body fat associated with potentially serious metabolic complications, including diabetes, hypertriglyceridemia, and steatohepatitis. Due to their rarity, most clinicians are not familiar with their diagnosis and management. This practice guideline summarizes the diagnosis and management of lipodystrophy syndromes not associated with HIV or injectable drugs. PARTICIPANTS: Seventeen participants were nominated by worldwide endocrine societies or selected by the committee as content experts. Funding was via an unrestricted educational grant from Astra Zeneca to the Pediatric Endocrine Society. Meetings were not open to the general public. EVIDENCE: A literature review was conducted by the committee. Recommendations of the committee were graded using the system of the American Heart Association. Expert opinion was used when published data were unavailable or scarce. CONSENSUS PROCESS: The guideline was drafted by committee members and reviewed, revised, and approved by the entire committee during group meetings. Contributing societies reviewed the document and provided approval. CONCLUSIONS: Lipodystrophy syndromes are heterogeneous and are diagnosed by clinical phenotype, supplemented by genetic testing in certain forms. Patients with most lipodystrophy syndromes should be screened for diabetes, dyslipidemia, and liver, kidney, and heart disease annually. Diet is essential for the management of metabolic complications of lipodystrophy. Metreleptin therapy is effective for metabolic complications in hypoleptinemic patients with generalized lipodystrophy and selected patients with partial lipodystrophy. Other treatments not specific for lipodystrophy may be helpful as well (eg, metformin for diabetes, and statins or fibrates for hyperlipidemia). Oral estrogens are contraindicated.

Myocardial Integrated Backscatter in Obese Adolescents: Associations with Measures of Adiposity and Left Ventricular Deformation.

BACKGROUND: Myocardial fibrosis has been proposed to play an important pathogenetic role in left ventricular (LV) dysfunction in obesity. This study tested the hypothesis that calibrated integrated backscatter (cIB) as a marker of myocardial fibrosis is altered in obese adolescents and explored its associations with adiposity, LV myocardial deformation, and metabolic parameters. METHODS/PRINCIPAL FINDINGS: Fifty-two obese adolescents and 38 non-obese controls were studied with conventional and speckle tracking echocardiography. The average cIB of ventricular septum and LV posterior wall was measured. In obese subjects, insulin resistance as estimated by homeostasis model assessment (HOMA-IR) and glucose tolerance were determined. Compared with controls, obese subjects had significantly greater cIB of ventricular septum (-16.8±7.8 dB vs -23.2±7.8 dB, p<0.001), LV posterior wall (-20.5±5.6 dBvs -25.0±5.1 dB, p<0.001) and their average (-18.7±5.7 dB vs -24.1±5.0 dB, p<0.001). For myocardial deformation, obese subjects had significantly reduced LV longitudinal systolic strain rate (SR) (p = 0.045) and early diastolic SR (p = 0.015), and LV circumferential systolic strain (p = 0.008), but greater LV longitudinal late diastolic SR (p<0.001), and radial early (p = 0.037) and late (p = 0.002) diastolic SR than controls. For the entire cohort, myocardial cIB correlated positively with body mass index (r = 0.45, p<0.001) and waist circumference (r = 0.45, p<0.001), but negatively with LV circumferential systolic strain (r = -0.23, p = 0.03) and systolic SR (r = -0.25, p = 0.016). Among obese subjects, cIB tended to correlate with HOMA-IR (r = 0.26, p = 0.07). CONCLUSION: Obese adolescents already exhibit evidence of increased myocardial fibrosis, which is associated with measures of adiposity and impaired LV circumferential myocardial deformation.

The clinical significance of aldosterone synthase deficiency: report of a novel mutation in the CYP11B2 gene.

BACKGROUND: Aldosterone synthase (CYP11B2) deficiency is a rare autosomal recessive disorder, usually presenting with severe salt-wasting in infancy or stress-induced hyperkalaemia and postural hypotension in adulthood. Neonatal screening for congenital adrenal hyperplasia, another cause of salt wasting, using 17-hydroxyprogesterone measurement would fail to detect aldosterone synthase deficiency, a diagnosis which may be missed until the patient presents with salt-wasting crisis. Due to this potential life-threatening risk, comprehensive hormonal investigation followed by genetic confirmation for suspected patients would facilitate clinical management of the patient and assessment of the genetic implication in their offspring. CASE PRESENTATION: We describe a 33-year old Chinese man who presented in infancy with life-threatening hyponatraemia and failure to thrive, but remained asymptomatic on fludrocortisone since. Chromosomal analysis confirmed a normal male karyotype of 46, XY. Plasma steroid profile showed high plasma renin activity, low aldosterone level, and elevated 18-hydroxycorticosterone, compatible with type 2 aldosterone synthase deficiency. The patient was heterozygous for a novel CYP11B2 mutation: c.977C > A (p.Thr326Lys) in exon 3. He also carried a heterozygous mutation c.523_525delAAG (p.Lys175del) in exon 6, a known pathogenic mutation causing aldosterone synthase deficiency. Sequencing of CYP11B2 in his parents demonstrated that the mother was heterozygous for c.977C > A, and the father was heterozygous for c.523_525delAAG. CONCLUSION: Although a rare cause of hyperreninaemic hypoaldosteronism, aldosterone synthase deficiency should be suspected and the diagnosis sought in patients who present with life-threatening salt-wasting in infancy, as it has a good long-term prognosis when adequate fludrocortisone replacement is instituted. To our knowledge, this is the first Chinese patient in which the molecular basis of aldosterone synthase deficiency has been identified.

Diagnosis of 5α-reductase 2 deficiency: is measurement of dihydrotestosterone essential?

BACKGROUND: 5α-Reductase 2 deficiency (5ARD) is a known cause of 46,XY disorders of sex development (DSD). Traditionally, the diagnosis relies on dihydrotestosterone (DHT) measurement, but the results are often equivocal, potentially leading to misdiagnosis. We reviewed alternative approaches for diagnosis of 5ARD. METHODS: We conducted a retrospective review of the results of urinary steroid profiling (USP) by GC-MS and mutational analysis of SRD5A2 [steroid-5-alpha-reductase, alpha polypeptide 2 (3-oxo-5 alpha-steroid delta 4-dehydrogenase alpha 2)] by PCR and direct DNA sequencing of all 46,XY DSD patients referred to our laboratory with biochemical and/or genetic findings compatible with 5ARD. We also performed a literature review on the laboratory findings of all 5ARD cases reported in the past 10 years. RESULTS: Of 16 patients diagnosed with 5ARD between January 2003 and July 2012, 15 underwent USP, and all showed characteristically low 5α- to 5ß-reduced steroid metabolite ratios. Four patients had DHT measured, but 2 did not reach the diagnostic cutoff. In all 12 patients who underwent genetic analysis, 2 mutations of the SRD5A2 gene were detected to confirm the diagnosis. Twenty-four publications involving 149 patients with 5ARD were published in the review period. Fewer than half of these patients had DHT tested. Nearly 95% of them had the diagnosis confirmed genetically. CONCLUSIONS: 5ARD can be confidently diagnosed by USP at 3 months postnatally and confirmed by mutational analysis of SRD5A2. Interpretation of DHT results may be problematic and is not essential in the diagnosis of 5ARD. We propose new diagnostic algorithms for 46,XY DSD.

Management of massive osteolysis of the mandible: a case report.

The management of a previously reported case of massive osteolysis of the mandible with intravenous bisphosphonate, vascularized free bone graft, and dental implants is reported. Restoration of adequate cosmetics and masticatory function was achieved. Despite the use of bisphosphonates, there were no complications with osseointegration. The reconstruction remained stable and functional 6 years afterward.

Late measures of microstructural alterations in severe neonatal hypoxic-ischemic encephalopathy by MR diffusion tensor imaging.

Neonatal hypoxic-ischemic encephalopathy is a major cause of brain damage in infants, and is associated with periventricular white matter injury and chronic neurological dysfunctions. However, the mechanisms of the chronic white matter injury and reorganization are still unclear. In this study, in vivo diffusion tensor imaging (DTI) was employed to evaluate the late changes of white matter microstructural integrity in the rat brains at 10 weeks after severe neonatal hypoxic-ischemic insults at postnatal day 7. In the fractional anisotropy directionality map, qualitative evaluation showed that a dorsoventrally oriented fiber bundle extended from the corpus callosum into the cyst in the anterior brain, whilst the posterior peri-infarct areas had similar fiber orientations as the contralateral internal capsule, optic tract and fimbria of hippocampus. Compared to the contralateral hemisphere, significantly higher fractional anisotropy, axial diffusivity and diffusion trace value were observed quantitatively in the distal end of the extended fiber bundle connecting the anterior and posterior white matters rostrocaudally. A significantly lower fractional anisotropy but higher axial and radial diffusivities and trace were also found in the ipsilateral corpus callosum, proximal external capsule and anterior commissure, while slightly lower fractional anisotropy and axial diffusivity were noticed in the ipsilateral internal capsule and optic nerve. It was suggested that increased fractional anisotropy, axial diffusivity and trace characterize white matter reorganization in chronic neonatal hypoxic-ischemic insults, whereas reduction in fractional anisotropy appears to characterize two types of white matter lesions, with significantly higher axial and radial diffusivities and trace being primary and slightly lower axial diffusivity being secondary. Combined with fractional anisotropy directionality map, in vivo DTI provides important indices to differentiate the chronic effects of severe neonatal hypoxic-ischemic injury and recovery globally, quantitatively and non-invasively.

Characterization of white matter injury in a hypoxic-ischemic neonatal rat model by diffusion tensor MRI.

BACKGROUND AND PURPOSE: We evaluate white matter (WM) injury after hypoxic-ischemic (HI) insult in a neonatal rat model using diffusion tensor imaging (DTI) to determine whether lambda(parallel) and lambda(perpendicular) are able to characterize type and severity of brain damage. METHODS: Eighteen 7-day-old Sprague-Dawley rats underwent unilateral ligation of left common carotid artery followed by 50 minutes (n=9) or 90 minutes (n=9) of hypoxia at 37 degrees C. Rats were divided into 2 groups, according to absence (group A, n=11) or presence (group B, n=7) of cystic lesions on D7 post-HI T2-weighted imaging. DTI was performed for all rats at D1 and for group A rats at D7 post-HI. Signal intensity of ipsilateral and contralateral external capsule (EC) on D1 was compared by paired t test, with histological correlation. RESULTS: Group A rats had significantly reduced FA, elevated trace, elevated lambda(perpendicular), and similar lambda(parallel) on D1 in the ipsilateral compared to contralateral EC, whereas group B rats had significant reduction in all parameters in the ipsilateral EC. Elevated trace normalized on D7 in group A rats. Histopathologic results demonstrated reduced myelination in group A noncystic HI and severe necrosis in group B cystic HI. CONCLUSIONS: Increased lambda(perpendicular) with no significant change in lambda(parallel) appears to characterize noncystic WM injury with reduced myelination, whereas reduction in both lambda(parallel) and lambda(perpendicular) characterize severe damage with loss of structural integrity and necrosis. Combining with FA and trace, lambda(parallel) and lambda(perpendicular) provide additional information which reflects type and severity of HI injury.

Proteomic analysis of neonatal mouse brain: evidence for hypoxia- and ischemia-induced dephosphorylation of collapsin response mediator proteins.

Perinatal hypoxia and ischemia (HI) are a significant cause of mortality and morbidity. To understand the molecular mechanisms for HI-induced brain damage, here we used a proteomic approach to analyze the alteration and modification of proteins in neonatal mouse brain 24 h after HI treatment. Significant changes of collapsin response mediator proteins (CRMPs) were observed in HI brain. CRMPs are a family of cytosolic proteins involved in axonal guidance and neuronal outgrowth. We found that CRMP2, CRMP4 and CRMP5 proteins were altered post-translationally after HI treatment. Mass spectrometric and Western blot analyses detected hypophosphorylated CRMP proteins after HI. Further analysis of CRMP kinases indicated inactivation of cyclin dependent kinase 5 (CDK5), a priming kinase of CRMPs and a neuronal specific kinase that plays pivotal roles in neuronal development and survival. The reduction of CDK5 activity was associated with underexpression of its activator p35. Taken together, our findings reveal HI-induced dephosphorylation of CRMPs in neonatal brain and suggest a novel mechanism for this modification. Hypophosphorylated CRMPs might be implicated in the pathogenesis of HI-related neurological disorders.

Manganese-enhanced MRI detection of neurodegeneration in neonatal hypoxic-ischemic cerebral injury.

In this study, we investigated the Mn-enhanced MRI (MEMRI) for detecting neurodegenerative processes in neonatal hypoxic-ischemic (H-I) cerebral injury. Seven-day-old rats were induced with H-I injury, and scanned for T1-weighted image (T1WI) and T2-weighted image (T2WI) with and without systemic MnCl2 administration. Serial histological analysis was performed for Mn-superoxide dismutase (Mn-SOD) and glutamine synthetase (GS), which are Mn-binding enzymes against the oxidative stress and glutamate excitotoxicity in neurodegeneration. In the acute phase (first 2 days), the ipsilateral lesion exhibited no Mn enhancement in T1WIs, with histology showing no Mn-SOD and GS production. In the mid-phase (from day 3), Mn enhancement was found in the cortex, basal ganglia, and hippocampus, correlating with local Mn-SOD and GS increase. In the late phase, the enhancement became more localized to the pericyst basal ganglia and cortex, and then gradually diminished. In T2WIs, a signal decrease was observed from day 3 in the corresponding regions. Hypointense voids gradually formed in the late phase, correlating with the local iron accumulation. H-I rats without Mn2+ administration exhibited similar but weak changes in T1WIs and T2WIs from days 14 and 7, respectively. These results indicate that Mn2+ may be a useful in vivo probe for monitoring Mn-SOD and GS enzymatic activities.

A 3D collagen microsphere culture system for GDNF-secreting HEK293 cells with enhanced protein productivity.

Mammalian cell culture technology has been used for decades in mass production of therapeutic proteins. However, unrestricted cell proliferation usually results in low-protein productivity. Controlled proliferation technologies such as metabolism intervention and genetic manipulation are therefore applied to enhance the productivity. Nevertheless, these strategies induced growth arrest with reduced viability and increased apoptosis. In this study, we report a new controlled proliferation technology by encapsulating human embryonic kidney (HEK) 293 cells over-expressing glial-derived neurotrophic factor (GDNF) in 3D collagen microspheres for extended culture. We investigated the viability, proliferation, cell cycle and GDNF productivity of HEK293 cells in microspheres as compared to monolayer culture. This system provides a physiologically relevant tissue-like environment for cells to grow and exerts proliferation control throughout the culture period without compromising the viability. A significant increase in the production rate of GDNF was found in the 3D microsphere system comparing with the monolayer culture. GDNF productivity was also significantly affected by the initial cell number and the serum concentration. The secreted GDNF was still bioactive as it induced neurite extension in PC12 cells. In summary, the 3D collagen microsphere system presents a cost-effective controlled growth technology for protein production in pharmaceutical manufacturing.

Comparing diffusion-weighted and T2-weighted MR imaging for the quantification of infarct size in a neonatal rat hypoxic-ischemic model at 24h post-injury.

PURPOSE: In a neonatal rat model of hypoxic-ischemic (HI) brain injury, using T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI), we aim to determine the best MRI method of lesion quantification that reflects infarct size. MATERIALS AND METHODS: Twenty 7-day-old rats underwent MRI 24h after HI brain injury was induced. Lesion size relative to whole brain was measured using T2WI and apparent diffusion coefficient (ADC) maps, applying thresholds of 60%, 70% and 80% contralateral control hemisphere mean ADC, and at day 10 post-HI on pathology with TTC staining. Multiple linear regression analysis was used to study the relationships between lesion size at MRI and pathology. RESULTS: Lesion size measurement using all MRI methods significantly correlated with infarct size at pathology; using T2WI, r=0.808 (p<0.001), using 80% ADC, 70% ADC and 60% ADC thresholds, r=0.888 (p<0.001), 0.761, (p<0.001) and 0.569 (p=0.014), respectively. Eighty percent ADC threshold was found to be the only significant independent predictor of final infarct volume (adjusted R(2)=0.775). CONCLUSION: At 24h post-HI, lesion size on DWI, using 80% ADC threshold is the best predictor of final infarct volume. Although T2WI performed less well, it has the advantage of superior spatial resolution and is technically less demanding. These are important considerations for experiments which utilize MRI as a surrogate method for lesion quantification in the neonatal rat HI model.