Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSC) inhibit the proliferation of K562 (human erythromyeloblastoid leukaemic cell line).

hUCB-MSC (human umbilical cord blood-derived mesenchymal stem cells) offer an attractive alternative to bone marrow-derived MSC for cell-based therapy by being less invasive a source of biological material. We have evaluated the effect of hUCB-MSC on the proliferation of K562 (an erythromyeloblastoid cell line) and the cytokine secretion pattern of hUCB-MSC. Co-culturing of hUCB-MSC and K562 resulted in inhibition of proliferation of K562 in a dose-dependent manner. However, the anti-proliferative effect was reduced in transwells, suggesting the importance of direct cell-to-cell contact. hUCB-MSC inhibited proliferation of K562, arresting them in the G0 /G1 phase. NO (nitric oxide) was not involved in the hUCB-MSC-mediated tumour suppression. The presence of IL-6 (interleukin 6) and IL-8 were obvious in the hUCB-MSC conditioned media, but no significant increase was found in 29 other cytokines. Th1 cytokines, IFNα (interferon α), Th2 cytokine IL-4 and Th17 cytokine, IL-17 were not secreted by hUCB-MSC. There was an increase in the number of hUCB-MSC expressing the latent membrane-bound form of TGFß1 co-cultured with K562. The anti-proliferative effect of hUCB-MSC was due to arrest of the growth of K562 in the G0 /G1 phase. The mechanisms underlying increased IL-6 and IL-8 secretion and LAP (latency-associated peptide; TGFß1) by hUCB-MSC remains unknown.

Generation of mesenchymal stem cell from human umbilical cord tissue using a combination enzymatic and mechanical disassociation method.

MSCs (mesenchymal stem cells) promise a great potential for regenerative medicine due to their unique properties of self-renewal, high plasticity, modulation of immune response and the flexibility for genetic modification. Therefore, the increasing demand for cellular therapy necessitates a larger-scale production of MSC; however, the technical and ethical issues had put a halt on it. To date, studies have shown that MSC could be derived from human UC (umbilical cord), which is once considered as clinical waste. We have compared the two conventional methods which are classic enzymatic digestion and explant method with our newly tailored enzymatic-mechanical disassociation method to generate UC-MSC. The generated UC-MSCs from the methods above were characterized based on their immunophenotyping, early embryonic transcription factors expression and mesodermal differentiation ability. Our results show that enzymatic-mechanical disassociation method increase the initial nucleated cell yield greatly (approximately 160-fold) and maximized the successful rate of UC-MSC generation. Enzymatic-mechanical disassociation-derived UC-MSC exhibited fibroblastic morphology and surface markers expression of CD105, CD73, CD29, CD90 and MHC class I. Furthermore, these cells constitutively express early embryonic transcription factors (Nanog, Oct-4, Sox-2 and Rex-1), as confirmed by RT-PCR, indicating their multipotency and high self-renewal capacity. They are also capable of differentiating into osteoblasts and adipocytes when given an appropriate induction. The present study demonstrates a new and efficient approach in generating MSC from UC, hence serving as ideal alternative source of mesenchymal stem cell for clinical and research use.

Genotyping and drug resistance profile of Candida spp. in recurrent and one-off vaginitis, and high association of non-albicans species with non-pregnant status.

Recurrent vulvovaginal candidiasis affects women worldwide and the resistance to azole drugs may be an important factor. The extent of strain-to-strain variation within a species and its relationship to the ability of the organism to colonize the vulvovaginal mucosa is not well established. The aims of this study were to compare: (i) the genotypes of Candida strains in sequential infections in patients with recurrent vaginitis, (ii) the genotypes of strains in patients with only one episode of infection in a period of 1 year and (iii) determine the in vitro antifungal susceptibilities of strains that cause recurrent vaginitis. Fifty-one cultured specimens from six distinct Candida species were genotyped via random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) method using the ERIC1 and ERIC2 primers (ERIC, enterobacterial repetitive intergenic consensus). Statistical analyses allowed three different scenarios to be discerned for recurrent cases: (i) strain maintenance without genetic variation, (ii) strain maintenance with minor genetic variation and (iii) outright strain replacement. The genetic relatedness between strains from patients with recurrent vaginitis and patients with single episode of vaginitis were demonstrated by the dendogramme and the mean pairwise similarity coefficient S(AB) for the intergroup comparison was 0.223. However, intragroup genetic relatedness was slightly higher than intergroup comparison, with mean S(AB) of 0.261 and 0.331 for Groups I and II, respectively. A high proportion of Group I isolates (87.5%) causing recurrent infections were resistant to ketoconazole, whereas 41.7% of these isolates were cross-resistant to both clotrimazole and ketoconazole as shown by the in vitro antifungal susceptibility test, especially for C. glabrata isolates. Pregnancy status of patients displayed a highly significant association with C. albicans species whereas non-albicans species had a markedly higher prevalence in non-pregnant patients (p<0.001). These results may have a profound impact on the management of vaginal candidiasis, especially in recurrent cases.

Genetic relatedness of Candida strains isolated from women with vaginal candidiasis in Malaysia.

The aims of this study were to compare the genetic relatedness of: (i) sequential and single isolates of Candida strains from women with recurrent vaginal candidiasis (RVC); and (ii) Candida strains from women who had only one episode of infection within a 1-year period. In total, 87 isolates from 71 patients were cultured, speciated and genotyped by random amplification of polymorphic DNA (RAPD) analysis. Patients were categorized into three groups, namely those with: (i) a history of RVC from whom two or more yeast isolates were obtained (group A); (ii) a history of RVC from whom only a single isolate was obtained (group B); and (iii) a single episode of vaginal candidiasis within a 1-year period (group C). Six yeast species were detected: Candida albicans, Candida glabrata, Candida lusitaniae, Candida famata, Candida krusei and Candida parapsilosis. Interestingly, the prevalence of non-albicans species was higher in group A patients (50 %) than in patients in groups B (36 %) or C (18.9 %). Eighty RAPD profiles were observed, with a total of 61 polymorphic PCR fragments of distinct sizes. Clustering analysis showed that, overall, the majority of patients in group A had recurrent infections caused by highly similar, but not identical, sequential strains [mean pairwise similarity coefficient (S(AB)) = 0.721 +/- 0.308]. The range of mean S(AB) values for intergroup comparisons for C. albicans isolates alone was 0.50-0.56, suggesting that there was no significant relatedness between strains from different groups. Genetic similarity of C. albicans isolates from patients in group A was lower than that of C. albicans isolates from patients in group C (mean S(AB) = 0.532 +/- 0.249 and 0.636 +/- 0.206, respectively); this difference was statistically significant (P = 0.036). These results demonstrate that the cause of recurrent infections varies among individuals and ranges between strain maintenance, strain microevolution and strain replacement; the major scenario is strain maintenance with microevolution. They also show that C. albicans strains that cause recurrent infections are less similar to each other than strains that cause one-off infections, suggesting that the former may represent more virulent subtypes.

Delivery of macrosomic babies: management and outcomes of 330 cases.

This study reviews the deliveries of macrosomic babies and their outcomes. A total of 330 macrosomic (birth weight > or =4 kg) cases were studied retrospectively from July 1999 to December 1999 in the Maternity Hospital of Kuala Lumpur. The variables studied included induction of labour, mode of delivery and the incidence of maternal and perinatal complications. Three hundred and thirty macrosomic infants were delivered during the period of study. Vaginal delivery was achived in 56% of the study cases. The percentage of vaginal delivery was higher among those who had induction of labour (63%) compared to the group without induction of labour (50%). Vaginal delivery was planned in 267 mothers and of these 69% achieved vaginal delivery. Twelve per cent of the macrosomic infants were delivered by elective caesarean section. Shoulder dystocia occurred in 4.9% of vaginal deliveries. Eighty-eight neonates were admitted to the special care nursery unit and 57% of these infants were delivered by elective caesarean section. Perineal trauma occurred in 26% of vaginal deliveries. Post-partum haemorrhage occurred in 32% of caesarean deliveries compared to 4% in vaginal deliveries. Two cases of stillbirths were documented but no maternal death occurred during the period of study. Vaginal delivery is the most frequent mode of delivery for a fetus weighing in excess of 4 kg and vaginal delivery should be attempted in the absence of contraindications, because vaginal delivery has less maternal morbidity compared to caesarean delivery. However, shoulder dystocia remains a significant complication of vaginal delivery for macrosomic fetuses.