Biomedical subjects

Tong Guo

Publications and source records attributed to Tong Guo.

11 recordsLinked to original sources

PubMed2006

Capillary separations enabling tissue proteomics-based biomarker discovery.

Development of the capability to enable large-scale proteome studies, analogous to comprehensive gene expression analysis, will clearly have far-reaching impacts on protein biomarker investigations of human diseases such as cancer through interrogation of the archived fresh frozen and formalin-fixed and paraffin-embedded tissue collections. This review therefore focuses on the most recent advances in microdissection techniques and proteome platforms for procuring homogeneous subpopulations of tumor cells or structures and performing comprehensive analysis of protein profiles within tissue specimens, respectively. Developments in capillary separations capable of providing extremely high resolving power and selective analyte enrichment are particularly highlighted for their roles within the broader context of a state-of-the-art integrated tissue proteome effort. The capabilities of CIEF-based multidimensional separations for performing proteome analysis from minute samples create new opportunities in the pursuit of biomarker discovery using enriched and selected cell populations procured from tissue specimens. These proteome technological advances combined with recently developed tissue microdissection techniques provide powerful tools for those seeking to gain a greater understanding at the global level of the cellular machinery associated with human diseases such as cancer.

Biomarkers↗

PubMed2006

Characterization of the human salivary proteome by capillary isoelectric focusing/nanoreversed-phase liquid chromatography coupled with ESI-tandem MS.

Saliva is a readily available body fluid with great diagnostic potential. The foundation for saliva-based diagnostics, however, is the development of a complete catalog of secreted and "leaked" proteins detectable in saliva. By employing a capillary isoelectric focusing-based multidimensional separation platform coupled with electrospray ionization tandem mass spectrometry (MS), a total of 5338 distinct peptides were sequenced, leading to the identification of 1381 distinct proteins. A search of bacterial protein sequences also identified many peptides unique to several organisms and unique to the NCBI nonredundant database. To the best of our knowledge, this proteome study represents the largest catalog of proteins measured from a single saliva sample to date. Data analysis was performed on individual MS/MS spectra using the highly specific peptide identification algorithm, OMSSA. Searches were conducted against a decoyed SwissProt human database to control the false-positive rate at 1%. Furthermore, the well-curated SwissProt sequences represent perhaps the least redundant human protein sequence database (12,484 records versus the 50,009 records found in the International Protein Index human database), therefore minimizing multiple protein inferences from single peptides. This combined bioanalytical and bioinformatic approach has established a solid foundation for building up the human salivary proteome for the realization of the diagnostic potential of saliva.

Chromatography, Liquid↗

PubMed2006

[Experimental study on repairing damage of corneal surface by mesenchymal stem cells transplantation].

OBJECTIVE: To investigate the survival, migration and differentiation of the cultured human mesenchymal stem cells derived from bone marrow (hMSCs) after transplanted onto the alkaline burn rabbit cornea. METHODS: Alkaline burn on rabbit corneas was induced with NaOH solution. One month later, hMSCs cultured with a feeding of amniotic membrane were transplanted onto the surface of alkaline burn rabbit corneas. Amniotic membrane alone transplantation was used at the same time as control group. One month after transplantation, the changes of corneal morphology were analyzed by clinical observations and HE staining. Immunohistochemistry was carried out with the antibodies against human nuclei and cytokeratin 12 to investigate the distribution and differentiation of hMSCs. RESULTS: The rabbit cornea became totally opaque one month after alkaline burn. Blood vessels could be seen within the superficial layer and stroma. The surface of cornea was rough and dry. There were many goblet cells found in the corneal epithelial layer. One month after transplantation of hMSCs, the surface of alkaline burn cornea became smoother. The amount of the new blood vessels of the cornea reduced and the goblet cells disappeared. Anti-human nuclei antibody staining showed positive cells on the surface layer and superficial stroma while cytokeratin 12 positive cells were only present in the epithelium layer. In the amniotic membrane transplantation control group, no clinical improvement of the cornea was found. Goblet cells were still seen on the corneal surface. Both anti-human nuclei antibody and cytokeratin 12 staining were negative. CONCLUSIONS: hMSCs survive and migrate to stroma after transplanted onto the surface of alkaline burn rabbit cornea. No rejection is detected. hMSCs on the corneal surface differentiate to corneal epithelium, where those migrated to the stroma differentiate to cells other than epithelium. hMSCs transplantation decrease corneal conjunctivization after alkaline burn.

Amnion↗

PubMed2005

Dynamic ergosterol- and ceramide-rich domains in the peroxisomal membrane serve as an organizing platform for peroxisome fusion.

We describe unusual ergosterol- and ceramide-rich (ECR) domains in the membrane of yeast peroxisomes. Several key features of these detergent-resistant domains, including the nature of their sphingolipid constituent and its unusual distribution across the membrane bilayer, clearly distinguish them from well characterized detergent-insoluble lipid rafts in the plasma membrane. A distinct set of peroxisomal proteins, including two ATPases, Pex1p and Pex6p, as well as phosphoinositide- and GTP-binding proteins, transiently associates with the cytosolic face of ECR domains. All of these proteins are essential for the fusion of the immature peroxisomal vesicles P1 and P2, the earliest intermediates in a multistep pathway leading to the formation of mature, metabolically active peroxisomes. Peroxisome fusion depends on the lateral movement of Pex1p, Pex6p, and phosphatidylinositol-4,5-bisphosphate-binding proteins from ECR domains to a detergent-soluble portion of the membrane, followed by their release to the cytosol. Our data suggest a model for the multistep reorganization of the multicomponent peroxisome fusion machinery that transiently associates with ECR domains.

ATPases Associated with Diverse Cellular Activitie↗

PubMed2004

Adsorption of methylene blue on Cu(II)-exchanged montmorillonite.

Cu(2+)-exchanged montmorillonite (CEM) was prepared using the method of ion exchange reaction. The goal was to determine the adsorption of methylene blue (MB) onto montmorillonite and CEM. The results showed that treatment with Cu(2+) slightly reduced the adsorption of montmorillonite. Temperature, pH value, and ionic strength in the medium had greater or smaller effects on interaction between MB and the clay. The data obtained from MB adsorption onto the tested adsorbents followed the Langmuir and BET equations. Also, the adsorption processes were endothermic and spontaneous in nature.

Journal Article↗

PubMed2004

Feeding effects on growth during infancy.

OBJECTIVE: To examine the effects of formula, other milks, other liquids, cereals, and other solid foods on growth during infancy. STUDY DESIGN: Observational cohort study nested within a large (n=17,046), cluster-randomized trial. We compared growth [weight-for-age, length-for-age, and weight-for-length z scores (WAZ, LAZ, WLZ) and head circumference (HC)] during the intervals 1 to 3, 3 to 6, 6 to 9, and 9 to 12 months, using hierarchical multivariate regression to control for size at the beginning of each interval, maternal education, geographic region, and urban versus rural location. RESULTS: Mixed BF and formula/other milk were associated with significantly higher (versus breast milk only) LAZ at 1 to 3 months (+0.038 and +0.047, respectively). In the 3- to 6-month interval, mixed BF and formula/other milk led to significantly higher WAZ (+0.125 and +0.139) and LAZ (+0.081 and +0.075), whereas cereal intake was associated with large and highly significant reductions in both measures (-0.293 and -0.240) and in HC (-0.291 cm). Mixed BF and formula/other milk continued to have positive albeit smaller associations with WAZ and LAZ in the 6- to 9-month and 9- to 12-month intervals. CONCLUSIONS: Our results confirm the growth-accelerating effects of formula and other milks (versus breast milk) on weight and length gain throughout infancy, with a dose-response gradient and largest associations observed at 3 to 6 months.

Body Height↗

PubMed2004

A new-style, slotted-cymbal transducer with large displacement and high energy transmission.

The cymbal transducer had more improved performances than the moonie transducer, but as with the moonie end caps, flexural motion of the cymbal end caps would cause high-tangential stresses, which could lead to loss of mechanical output energy. So, a new-style design, called slotted-cymbal transducer, is presented in this paper. The slotted-cymbal transducer released the tangential stresses by adopting a new-style, radial-slotted cymbal end caps. Through theoretical calculation and finite element analysis in collaboration with measurements, the slotted-cymbal transducer was demonstrated to possess high performances of displacement and energy transmission. This design would decrease the fundamental resonance frequencies of systems by different numbers of slots, and it would have more potential applications of low frequency and large displacement.

Journal Article↗

PubMed2003

Peroxisome division in the yeast Yarrowia lipolytica is regulated by a signal from inside the peroxisome.

We describe an unusual mechanism for organelle division. In the yeast Yarrowia lipolytica, only mature peroxisomes contain the complete set of matrix proteins. These mature peroxisomes assemble from several immature peroxisomal vesicles in a multistep pathway. The stepwise import of distinct subsets of matrix proteins into different immature intermediates along the pathway causes the redistribution of a peroxisomal protein, acyl-CoA oxidase (Aox), from the matrix to the membrane. A significant redistribution of Aox occurs only in mature peroxisomes. Inside mature peroxisomes, the membrane-bound pool of Aox interacts with Pex16p, a membrane-associated protein that negatively regulates the division of early intermediates in the pathway. This interaction inhibits the negative action of Pex16p, thereby allowing mature peroxisomes to divide.

Acyl-CoA Oxidase↗

PubMed2003

Infant growth and health outcomes associated with 3 compared with 6 mo of exclusive breastfeeding.

BACKGROUND: Opinions and recommendations about the optimal duration of exclusive breastfeeding have been strongly divided, but few published studies have provided direct evidence on the relative risks and benefits of different breastfeeding durations in recipient infants. OBJECTIVE: We examined the effects on infant growth and health of 3 compared with 6 mo of exclusive breastfeeding. DESIGN: We conducted an observational cohort study nested within a large randomized trial in Belarus by comparing 2862 infants exclusively breastfed for 3 mo (with continued mixed breastfeeding through >/= 6 mo) with 621 infants who were exclusively breastfed for >/= 6 mo. Regression to the mean, within-cluster correlation, and cluster- and individual-level confounding variables were accounted for by using multilevel regression analyses. RESULTS: From 3 to 6 mo, weight gain was slightly greater in the 3-mo group [difference: 29 g/mo (95% CI: 13, 45 g/mo)], as was length gain [difference: 1.1 mm (0.5, 1.6 mm)], but the 6-mo group had a faster length gain from 9 to 12 mo [difference: 0.9 mm/mo (0.3, 1.5 mm/mo)] and a larger head circumference at 12 mo [difference: 0.19 cm (0.07, 0.31 cm)]. A significant reduction in the incidence density of gastrointestinal infection was observed during the period from 3 to 6 mo in the 6-mo group [adjusted incidence density ratio: 0.35 (0.13, 0.96)], but no significant differences in risk of respiratory infectious outcomes or atopic eczema were apparent. CONCLUSIONS: Exclusive breastfeeding for 6 mo is associated with a lower risk of gastrointestinal infection and no demonstrable adverse health effects in the first year of life.

Adult↗

PubMed2002

Breastfeeding and infant growth: biology or bias?

BACKGROUND: Available evidence suggests that prolonged and exclusive breastfeeding is associated with lower infant weight and length by 6 to 12 months of age. This evidence, however, is based on observational studies, which are unable to separate the effects of feeding mode per se from selection bias, reverse causality, and the confounding effects of maternal attitudinal factors. DESIGN/METHODS: A cluster-randomized trial in the Republic of Belarus of a breastfeeding promotion intervention modeled on the World Health Organization (WHO)/UNICEF Baby-Friendly Hospital Initiative versus control (then current) infant feeding practices. Healthy, full-term, singleton breastfed infants (n = 17 046) weighing > or =2500 g were enrolled soon after birth and followed up at 1, 2, 3, 6, 9, and 12 months old for measurements of weight, length, and head circumference. Data were analyzed according to intention-to-treat, while accounting for within-cluster correlation. To assess the potential for bias in observational studies of breastfeeding, we also analyzed our data as if we had conducted an observational study by ignoring treatment, combining the 2 randomized groups, and comparing 1378 infants weaned in the first month and those breastfed for the full 12 months of follow-up with either > or =3 months (n = 1271) or > or =6 months (n = 251) of exclusive breastfeeding. RESULTS: Infants from the experimental sites were significantly more likely to be breastfed (to any degree) at 3, 6, 9, and 12 months and were far more likely to be exclusively breastfed at 3 months (43.3% vs 6.4%). Mean birth weight was nearly identical in the 2 groups (3448 g, experimental; 3446 g, control). Mean weight was significantly higher in the experimental group by 1 month of age (4341 vs 4280 g). The difference increased through 3 months (6153 g vs 6047 g), declined slowly thereafter, and disappeared by 12 months (10564 g vs 10571 g). Analysis by z scores confirmed that infants in both groups gained more weight than the WHO/Centers for Disease Control and Prevention reference, with no evidence of undernutrition in the control group. Length followed a similar pattern. In the observational analyses, infants weaned in the first month were slightly lighter and shorter at birth and their weight-for-age and length-for-age z scores declined by 1 month, but they caught up to both experimental and the other observational groups by 6 months and were heavier and longer by 12 months. Among infants in the 2 prolonged and exclusive breastfeeding groups, weight-for-age z scores fell slightly between 3 and 12 months; length-for-age fell below the reference by 6 months with catch-up to the reference by 12 months. Head circumference showed no significant differences at any age between the 2 trial groups or among the observational groups. CONCLUSIONS: Our data, the first in humans based on a randomized experiment, suggest that prolonged and exclusive breastfeeding may actually accelerate weight and length gain in the first few months, with no detectable deficit by 12 months old. These results add support to current WHO and UNICEF feeding recommendations. Our observational analysis showing faster weight and length gains with early weaning and slower gains with prolonged and exclusive breastfeeding may reflect unmeasured confounding differences or a true biological effect of formula feeding.

Breast Feeding↗

PubMed2002

[Preventing and treating effects of "changkun granules" on experimental acute renal failure induced by cisplatin in rats].

OBJECTIVE: To study the preventing and treating effects of "Changkun Granules" in experimental acute renal failure(ARF) induced by cisplatin in rats. METHODS: The ARF rats were administered the "Changkun Granules". Serum BUN and SCr of all the rats were measured and the renal morphology was evaluated. RESULTS: Serum BUN level in the "Changkun Granules" group was lower than the one in cisplatin group. "Changkun Granules" could also improve renal histology damage. CONCLUSION: The results indicated that "Changkun Granules" had certain protective effect on experimental ARF.

Acute Kidney Injury↗