Abstract 292: Magnetic-based Multi-layer Microparticles for Stem Cell Isolation, Enrichment, and Detachment

Due to the extensive therapeutic potential of endothelial progenitor cells (EPCs) in regenerative medicine, various techniques have been developed to isolate and expand them ex vivo . Yet these methods are limited by the use of harmful chemicals and difficulty in ex vivo stem cell expansion. The aim of this research was to develop multi-layer microparticles (MLMPs) that can magnetically isolate EPCs without using Ficoll and harsh shear forces, provide sequential proliferating and differentiating growth factor release for stem cell enrichment, and detach cells in response to temperature changes without the use of chemicals such as Trypsin. MLMPs consisted of a poly(lactic-co-glycolic acid) (PLGA) core embedded with magnetic nanoparticles and the temperature-sensitive polymer (poly( N -isopropyl acrylamide-allylamine): PNIPAAm-AH) shell. MLMPs were formulated and characterized for their physicochemical properties. Studies to investigate growth factor release, optimization concentrations of MLMPs and antibodies as well as the time required for maximal cell isolation were also carried out. Finally, effects of MLMPs on the growth of isolated cells were studied. MLMPs had core-shell structure with spherical morphology of 50-75 μm, and their growth factors were released in a sequential manner required for cell proliferation and differentiation. EPCs successfully attached to the polymer surface, while maintaining their morphology as verified from staining and SEM. Moreover, 64% EPCs were isolated over a period of 2 hours with 1 mg/ml MLMPs conjugated with 3 μg/ml CD34 antibodies. Cells were successfully detached from the particle surface by lowering the surrounding temperature to room temperature for a short time. MLMPs loaded with growth factors show an enhanced cell growth compared to those of commercial beads. These results indicate that MLMPs might have a significant impact on cell isolation and expansion technologies.

Treatment of femoral fractures in children: is titanium elastic nailing an improvement over hip spica casting?

PURPOSE

The purpose of the study was to assess the validity of surgical interference with elastic nailing in treating pediatric femur fractures in comparison with the traditional treatment method-hip spica casting.

METHODS

Sixteen consecutive femur fractures in children 5-15 years of age were recruited prospectively over 13 months. An equal number of age-matched children treated by spica casting were recruited retrospectively. Subtrochanteric, supracondylar femur fractures were excluded.

RESULTS

Fracture union occurred earlier in the surgical group (6 weeks) than in the spica group (8 weeks) (P = 0.001). Spica casting caused higher coronal plane angulation (P = 0.001), higher rotational malalignment (P < 0.001), higher limb length discrepancy at 1-year follow-up (P < 0.001), longer duration of immobilization (P < 0.001), later full weight-bearing (P < 0.001), and greater absence from school (P < 0.001). Flynn outcome scores were better with titanium elastic nailing than with hip spica casting.

CONCLUSION

Titanium elastic nailing led to better outcomes compared to hip spica casting in terms of earlier union, lower rates of malunion, shorter rehabilitation milestones, and better functional outcome scores.

Genome-wide scan identifies novel modifier loci of acromegalic phenotypes for isolated familial somatotropinoma

Isolated familial somatotropinoma (IFS) accounts for 18% of familial isolated pituitary adenoma (FIPA) cases. Recently, germline mutations of the aryl hydrocarbon receptor-interacting protein gene (AIP) have been found in families with pituitary adenoma predisposition, FIPA, and IFS. In this study, we investigate the AIP mutation status and perform a genome-wide scan to search for the modifier regions of acromegalic phenotypes in an IFS family of 31 aborigines from Borneo. Complete endocrine diagnosis and data could not be collected due to logistical and cultural reasons. AIP mutation screening was carried out by direct sequencing and the genome-wide scan was performed using 400 microsatellites. Non-parametric linkage analysis was performed to obtain the logarithm of odds (LOD) scores. A novel AIP frameshift mutation in exon 4 (c.500delC) (p.P167HfsX3) was identified in all members with acromegalic features, as well as in 15 members without acromegalic features, revealing incomplete penetrance of AIP. The data showed that patients with the same mutation may express acromegalic features of differing severity, suggesting the existence of modifier genes. The highest LOD score of 2.2 was obtained near D19S571 (19q13.41). We also found weak linkages on chromosomes 3q28, 8q12.1, and 21q22.13, with LOD scores of 1.1, 1.8, and 1.4 respectively. Our results show the first genome-wide scan that identifies novel modifier loci for acromegalic phenotypes in an IFS family. Identification of modifier loci may provide further insight into the disease mechanism and explain the clinical variability observed in its patients.

Effect of Notch inhibition on radiation in an explant model of glioblastoma multiforme

e22080

Background: Glioblastoma Multiforme (GBM) is highly radioresistant, possibly due to a subpopulation of Brain Tumor “Stem-like‘ Cells (BTSC) capable of repopulating the tumor. The Notch signaling pathway is essential for maintaining normal neural stem cells. We asked whether Notch inhibition can overcome radioresistance by allowing BTSCs to exit their stem cell state. Methods: To maintain the BTSCs in their original niche we used an organotypic culture method (explants). GBM explants are cultured on a semiporous membrane in an air-medium interface. They are treated with the Notch inhibitor DAPT, radiation or a combination thereof. Proliferation and neurosphere forming capacity are assessed. Results: The explant model faithfully maintained the cytoarchitecture of the tumor (preservation of blood vessels and pericytes) and its high proliferation rate (%ki67+ cells: 14.3% -17.1%). The effect of DAPT or radiation treatment alone differed among tumors (from no change to a two-fold and nine-fold decrease post DAPT or radiation respectively). However, in all tumors tested the combination of DAPT and radiation dramatically decreased the proliferation rate compared to either treatment alone (%ki67 + cells: 0.19%-2.24%). Interestingly the rate of neurosphere formation was highest following radiation alone (threefold increase). Neurosphere formation after DAPT treatment differed amongst the tumors from a decrease (fourfold) to an increase (twofold). The combination treatment resulted in a modest increase over control (twofold). Conclusions: Our data demonstrates that inhibition of proliferation does not correlate with the status of neurosphere forming ability, arguably a surrogate for cancer stem cell function. Combining radiation with notch inhibition has a profound effect on GBM proliferation, most likely due to selectively inhibiting the BTSC repopulating ability. Ongoing studies will determine the impact of this approach on tumor growth and progression in in vivo tumor models.

No significant financial relationships to disclose.

Demography and clinical course of ulcerative colitis in a multiracial Asian population: a nationwide study from Malaysia

OBJECTIVE

To establish the clinical course of ulcerative colitis (UC) in the Malaysian population, comparing the three major ethnic groups: Malay, Chinese and Indian.

METHODS

Patients who were diagnosed with UC from seven major medical referral centers in Malaysia were recruited. Their baseline characteristics, and the extent of the disease, its clinical course and complications were recorded.

RESULTS

A total of 118 patients was included. The extent of disease was as follows: proctitis alone in 22 (18.6%), sigmoid colon in 23 (19.5%), descending colon in 16 (13.6%), transverse colon in 11 (9.3%), ascending colon and pancolitis 46 (39%). Most patients had chronic intermittent disease. Extra-intestinal complications were seen in 27 (22.9%) patients and fulminant colitis was seen in four (3.4%). None developed colorectal cancer. The overall cumulative colectomy rates at 1, 5 and 10 years were 3.4% (CI: 0.9-8.5), 5.9% (CI: 1.9-13.2) and 15.6% (CI: 6.5-29.4), respectively. There was a higher prevalence of extra-intestinal manifestations and a trend towards more extensive disease among Indian patients. However, no significant differences were seen in the age of onset, the severity of disease (fulminant colitis, refractory disease) and the colectomy rate.

CONCLUSION

As in developed countries, most of our patients have a remitting and relapsing pattern of disease but the clinical course appears to be milder, with lower rates of colectomies. There are differences in clinical presentation among the three major ethnic groups, with Indians having a higher prevalence of extra-intestinal manifestations and a trend towards more extensive disease.

Treating leukemia in a resource poor setting

Acute lymphatic leukemia (ALL) is the commonest childhood malignancy in India; most patients have no access to specialized health care. Our experience in treating such children who are unable to avail of facilities at specialized centers is described here. The case records of 79 patients with acute lymphatic leukemia, treated at a Government Medical College in Kerala over 15 years were analyzed. Of the 73 patients who completed treatment, 23 survived (36%) 20 had event-free survival more than 5 years after remission. The utilization of available resources is described. We suggest twinning between specialized centers in India and peripheral hospitals as a means to reach more children.

Microalbuminuria prevalence study in hypertensive type 2 diabetic patients in Malaysia

Microalbuminuria is the earliest indicator of diabetic kidney disease and generalised vascular endothelial dysfunction. The Microalbuminuria Prevalence (MAP) Study was carried out to assess the prevalence of macroalbuminuria, microalbuminuria and normoalbuminuria in Asian hypertensive patients with type 2 diabetes on usual care. This paper presents a subanalysis of data from patients in Malaysia. In 733 analysed patients, the prevalence of macroalbuminuria and microalbuminuria was 15.7% and 39.7%, respectively. The high prevalence of diabetic nephropathy in these high-risk patients is a cause for concern, and the Malaysian Health Care system should be prepared for a pandemic of end-stage renal disease due to diabetic nephropathy.

Microbial growth in vials of Botulinum toxin following use in clinic

PURPOSE

Botulinum toxin has various applications in ophthalmology and is used in the outpatient department, where it is often exposed to room temperatures for 3-4 h. The manufacturer's recommendations are that the reconstituted toxin be stored in a refrigerator when not in use and discarded 4 h after reconstitution. The aim of our study was to examine such used bottles of Botulinum toxin for microbial growth after 4 h at room temperature.

METHODS AND RESULTS

Eleven consecutive bottles of Botulinum toxin used with aseptic precautions in the Ophthalmology outpatient clinics were exposed to room temperatures for 4 h. These were subsequently analysed for microbial growth. No growth was directly obtained from any of the Botulinum toxin bottles during our study.

CONCLUSIONS

This pilot study suggests that if aseptic precautions are followed during the use of Botulinum toxin, the contents of the bottle remain sterile despite being exposed to room temperatures for up to 4 h. This has implications on the use of the reconstituted toxin after the recommended 4 h.

Fasciolopsiasis: a first case report from Malaysia

Fasciolopsiasis is a disease caused by the largest intestinal fluke, Fasciolopsis buski. The disease is endemic in the Far East and Southeast Asia. Human acquires the infection after eating raw freshwater plants contaminated with the infective metacercariae. There has been no report of fasciolopsiasis either in man or in animal in Malaysia. We are reporting the first case of fasciolopsiasis in Malaysia in a 39-year-old female farmer, a native of Sabah (East Malaysia). This patient complained of cough and fever for a duration of two weeks, associated with loss of appetite and loss of weight. She had no history of traveling overseas. Physical examination showed pallor, multiple cervical and inguinal lymph nodes and hepatosplenomegaly. Laboratory investigations showed that she had iron deficiency anemia. There was leukocytosis and a raised ESR. Lymph node biopsy revealed a caseating granuloma. Stool examination was positive for the eggs of Fasciolopsis buski. The eggs measure 140 x 72.5 microm and are operculated. In this case, the patient did not present with symptoms suggestive of any intestinal parasitic infections. Detection of Fasciolopsis buski eggs in the stool was an incidental finding. She was diagnosed as a case of disseminated tuberculosis with fasciolopsiasis and was treated with antituberculosis drugs and praziquantel, respectively.

A case for a neonatal, low-dose BCG vaccination trial

The rational design of a successful vaccination strategy against tuberculosis requires certain kinds of information and must take account of several considerations: (i) the nature of the immune response that protects the large majority of individuals infected by Mycobacterium tuberculosis, designated as healthy contacts, must be defined and distinguished from that in tuberculosis patients, whose immune system must have failed; (ii) the vaccination strategy must incorporate a way of priming the immune system to guarantee in all individuals this protective response, normally generated in healthy contacts, upon natural infection by M. tuberculosis; (iii) the strategy must incorporate a mechanism for ensuring that the effectiveness of this priming is not abrogated by exposure to environmental mycobacteria; and (iv) the strategy must take account of the fact that the vaccinated population is genetically heterogeneous, and that individuals will therefore respond variably to most standard vaccination protocols. We describe a tentative proposal for how these interrelated problems might be solved and discuss predictions of this tentative vaccination strategy. Critical testing of the neonatal, low-dose BCG vaccination strategy can only be achieved by a field trial and we outline the considerations underlying this proposal.

Ultrastructural observations on effects of different concentrations of calcium and thyroxine in vitro on larval epidermal cells of Rana catesbeiana tadpoles

During anuran metamorphosis dramatic changes in morphogenesis and differentiation of epidermis occur under the influence of thyroid hormones. Modification of ionic calcium concentration also markedly alters the pattern of proliferation and differentiation in amphibian epidermal cells in vitro. The present study was designed to determine the direct effect of low (0.05 mM) and high (0.5 mM) calcium (Ca2+) in the absence or presence of thyroxine (10(-7) M) on epidermal cells of the body and tail tissue in vitro. When tail fin and body skin explants were maintained in low (0.05 mM) calcium for 48 h, normal ultrastructural morphology and integrity of the cells was observed in both the tissue types. When tissues were exposed to high levels of calcium (0.5 mM) in culture medium, tail epidermis showed stratification, and skein cells exhibited apoptosis, both in the presence or absence of thyroid hormones. Under high calcium conditions, the body epidermis showed keratinization of apical cells, apoptosis of skein cells, and increased desmosome formation. These results suggest that (1) optimal Ca2+ concentration for larval epidermal cells is quite low (0.05 mM), (2) high Ca2+ leads to keratinization only in body epidermis, and (3) apoptosis occurred in skein cells of both the tissues at high Ca2+ concentrations (0.5 mM). The present study therefore suggests that the extracellular calcium concentration regulates the process of cell death and differentiation in Rana catesbeiana larval epidermis, and this effect may be similar to the effect of calcium on mammalian epidermal cells.

Developmental implications of differential effects of calcium in tail and body skin of Anuran tadpoles

The effects of external Ca(++) on metamorphosis of Rana catesbeiana tadpoles were assessed. Treatment of tadpoles with Ca(++) (0.05 mM) during early prometamorphic stages induced precocious metamorphic events such as tail regression, shortening of the intestine, forelimb emergence, and keratinization of body epidermis within 23 days of treatment compared to control tadpoles still in mid-prometamorphic stages. These effects of Ca(++) are probably mediated by the thyroid gland, as indicated by histological features of the gland at the light and electron microscopic levels. Calcium levels of tail and body skin were measured at various stages of development by atomic absorption spectrophotometry. In control and experimental groups, body skin had significantly higher Ca(++) concentrations than tail skin. There were no statistically significant effects of developmental stage on Ca(++) levels of tail or body skin. Experimental Ca(++) treatment significantly increased Ca(++) concentration in tail but not body skin. Ultrastructure studies and gel electrophoresis indicated that calcium induced keratinization of body skin, but not tail epidermis. Ca(++)-treated tail epidermis showed various autolysing figures in apoptotic cells. In summary, calcium treatment accelerated metamorphosis and induced the following region-dependent cellular events: keratinization of body skin-a characteristic of adult epidermis-and programmed cell death in the tail. Whatever signal elicited by calcium in this experimentally induced accelerated metamorphosis is probably mediated via the thyroid gland.