Biomedical subjects

C P Pang

Publications and source records attributed to C P Pang.

At least 19 recordsLinked to original sources

PubMed2006

A novel genetic study of Chinese families with autosomal recessive retinitis pigmentosa.

Autosomal recessive retinitis pigmentosa (arRP) is the commonest form of RP worldwide. To date 22 loci have been implicated in the pathogenesis of this disease; however none of these loci independently account for a significant proportion of recessive RP. Linkage studies of arRP in consanguineous families have been mainly based on homozygosity mapping, but this strategy cannot be applied in the case of non-consanguineous families. Therefore, we implemented a systematic approach for identifying the disease locus in three non-consanguineous Chinese families with arRP. Initially, linkage analysis using SNPs/microsatellite markers or mutation screening of known arRP genes excluded all loci/genes except RP25 on chromosome 6. Subsequently a whole genome scan for the three families using the 10K GeneChip Mapping Array was performed, in order to identify the possible disease locus. To the best of our knowledge this is the first report on the utilisation of the 10K GeneChip to study linkage in non-consanguineous Chinese arRP. This analysis indicates that the studied families are probably linked to the RP25 locus, a well defined arRP locus in other populations. The identification of another ethnic group linked to RP25 is highly suggestive that this represents a major locus for arRP.

Asian People↗

PubMed2006

Uptake and distribution of catechins in fetal organs following in utero exposure in rats.

BACKGROUND: Although catechins are known to be powerful antioxidants, no reports have shown their transport to fetal organs. We investigated the distribution of catechins in fetal rat organs after maternal exposure to green tea extract (GTE). METHODS: GTE (550 mg/kg) or water was fed orally to pregnant dams at 15.5 days of gestation, the dams were sacrificed and fetal organs were dissected 0, 0.5, 1, 2, 3, 5, and 8 h later. Catechins and catechin gallates were determined by high-performance liquid chromatography (HPLC) after solid-phase extraction. RESULTS: In the GTE-treated group, catechins were detected in most of the fetal organs studied, including the brain, eyes, heart, lungs, kidneys and liver but not in the control group. The first peak times (T(max)) were about 0.5-1 h. The maximum concentrations (C(max)) of catechins in the fetal eye were about 2-10 times higher than in the other organs, ranging from 249 pmol/g for epicatechin (EC) to 831 pmol/g for epigallocatechin gallate (EGCG). Catechin gallates were generally more readily taken up by fetal organs than catechins. EGCG had the highest level of uptake according to area under the curve (AUC) plots and the highest C(max) in all organs. CONCLUSIONS: Various fetal organs had low but significant levels of catechins after GTE intake by the dams, and organ levels were found to be related to catechin structure. EGCG could be a potential candidate for antioxidant supplementation of the fetus in utero.

Animals↗

PubMed2006

An in vitro study on the compatibility and concentrations of combinations of vancomycin, amikacin, and dexamethasone in human vitreous.

PURPOSE: To investigate the precipitation process of a mixture of vancomycin, amikacin, and dexamethasone by equilibrium dialysis and its subsequent effect on the levels of available-free antibiotics and steroid. METHODS: Concentrations of amikacin, vancomycin, and dexamethasone in an equilibrium dialysis chamber were measured during the equilibrium process by high-performance liquid chromatography and fluorescence polarisation immunoassay. Vitreous were used as the medium of dialysis, with the three medications prepared in normal saline (NS) and balanced salt solution plus (BSS Plus) separately. RESULTS: Amikacin showed no measurable loss in NS or BSS Plus, either alone or when mixed with vancomycin or dexamethasone. Vancomycin showed minimal loss in BSS Plus, either alone or when mixed with amikacin or dexamethasone. Dexamethasone showed a median loss of 16 and 15% when incubated alone in NS and BSS Plus, respectively, at 48 h. When mixed with vancomycin or amikacin in BSS Plus, it showed a median loss of 13 and 12%, respectively, at 48 h. There was no statistically significant difference in the loss of dexamethasone under various conditions. In equilibrium dialysis in vitreous, amikacin, vancomycin, and dexamethasone reached equilibrium within 24 h and with no loss up to 192 h. There was no difference observed when the medications were prepared in NS or BSS Plus. CONCLUSIONS: Both amikacin and vancomycin did not show precipitation or decrease in concentration in NS or BSS Plus. Dexamethasone showed relatively small percentage loss. As a result, treatment of endophthalmitis with vancomycin and amikacin combination is preferred.

Amikacin↗

PubMed2006

Molecular characterization of the developmental gene in eyes: through data-mining on integrated transcriptome databases.

OBJECTIVES: Our aim was to utilize publicly available and proprietary sources to discover candidate genes important for ocular development. DESIGN AND METHODS: The collated information on our 5092 non-redundant clusters was grouped and functional annotation was conducted using gene ontology (FatiGO) for categorizing them with respect to molecular function. The web-based viewer technological platform (H-InvDB) was employed for transcription analyses of in-house high quality fetal eye Expressed Sequence Tags (ESTs). Eye-specific ESTs were also analyzed across species by using EMBEST. RESULTS: According to adult eye cDNA libraries, nucleic acid binding and cell structure/cytoskeletal protein genes were the most abundant among the ESTs of fetal eyes. Using cDNA assembly in H-InvDB, 20 (80%) of the 25 most commonly expressed genes in the human eye are also expressed in extraocular tissues. The crystalline gamma S gene is highly expressed in the eye, but not in other tissues. We used EMBEST to compare human fetal eye and octopus eye ESTs and the expression similarity was low (1.6%). This indicated that our fetal eye library contains genes necessary for the developmental process and biological function of the eye, which may not be expressed in the fully developed octopus eyes. The human fetal eye cDNA library also contained highly abundant eye tissue genes, including alphaA-crystallin, eukaryotic translation elongation factor 1 alpha 1 (EEF1A1), bestrophin (VMD2), cystatin C, and transforming growth factor, beta-induced (BIGH3). CONCLUSIONS: Our annotated EST set provides a valuable resource for gene discovery and functional genomic analysis. This display will help to appreciate the strengths and weaknesses of the different technological platforms, so that in future studies the maximum amount of beneficial information can be derived from the appropriate use of each method.

Animals↗

PubMed2006

A novel missense RP1 mutation in retinitis pigmentosa.

AIMS: More than 20 mutations associated with retinitis pigmentosa (RP) have been identified in the retinitis pigmentosa 1 (RP1) gene, all of them leading to the production of a truncated protein without 50-70% of the C-terminal of the RP1 protein. RP1 was recently found to be a microtubule-associated protein (MAP) and responsible for the organisation of the photoreceptor outer segment. The N-terminal doublecortin (DCX) domain of RP1 is essential for its function. But how the C-terminal of the protein affects its function is still not known. This study aims to get a better understanding of the RP1 gene by mutation screening on RP patients. METHODS: Peripheral blood was taken from 72 RP patients. Together with 101 RP patients and 190 control subjects previously reported, mutation screening was performed by polymerase chain reaction (PCR) and direct sequencing. Statistical analysis was performed using SPSS. RESULTS: Two novel missense sequence changes, D984G and C727W, and one novel variant, 6492T>G, at the 3' untranslated region were found. They were not found in 190 control subjects. D984G causes RP. It creates two possible N-myristoylation sites according to PROSITE. C727W does not segregate with RP in the family. It abolishes an N-myristoylation site. R872H, a previously reported polymorphism, was predominantly present in control subjects (P=0.001). CONCLUSIONS: Our results suggest that disruption of the C-terminal of RP1 may be associated with the development of RP, and the possible involvement of the RP1 polypeptide downstream of its DCX domain in normal RP1 function.

Adult↗

PubMed2005

Genomic annotation of 15,809 ESTs identified from pooled early gestation human eyes.

To complement cDNA libraries from the human eye at early gestation and to discover candidate genes associated with early ocular development, we used freshly dissected human eyeballs from week 9-14 of gestation to construct the early human fetal eye cDNA library. A total of 15,809 clones were isolated and sequenced from the unamplified and unnormalized library. We screened 11,246 good-quality ESTs, leading to the identification of 5,534 nonredundant clusters. Among them, 4,010 (72%) genes matched in the human protein database (Ensembl). The remaining 28% (1,524) corresponded to potentially novel or previously unidentified ESTs. We used BLASTX to compare our EST data with eight organisms and found common expression of a high portion of genes: Caenorhabditis briggsae (26%), Caenorhabditis elegans (27%), Anopheles gambiae (37%), Drosophila melanogaster (32%), Danio rerio (42%), Fugu rubripes (49%), Rattus norvegicusvalitus (52%), and Mus musculus (59%). Nevertheless, 48% (2,680 of 5,534) of the genes expressed in the early developing eye were not shared with current NEIBank human eye cDNA data. In addition, eight known retinal disease genes existed in our ESTs. Among them, six (COL11A1, BBS5, PDE6B, OAT, VMD2, and PGK1) were conserved among the genomes of other organisms, indicating that our annotated EST set provides not only a valuable resource for gene discovery and functional genomic analysis but also for phylogenetic analysis. Our foremost early gestation human eye cDNA library could provide detailed comparisons across species to identify physiological functions of genes and to elucidate evolutionary mechanisms.

Animals↗

PubMed2005

Gene mutations in retinitis pigmentosa and their clinical implications.

Retinitis pigmentosa (RP) is a group of inherited progressive retinal diseases affecting about 1 in 3500 people worldwide. So far, there is no prevention or cure, with permanent visual loss or even blindness the ultimate consequence usually after midlife. The genetics of RP are complex. It can be sporadic, autosomal dominant, autosomal recessive, or X-linked. Thirty-two genes are known to be associated with RP, sometimes the same gene gets involved in different inheritance traits. Some RP cases have a digenic cause. About 60% RP cases still have no known genetic cause. A large number of mutations cause RP, and they can be deletions, insertions, or substitutions that cause missense mutations or truncations. The RHO, RP1, and RPGR genes contribute the greatest number of known mutations causative of RP. But there is no single mutation that alone accounts for more than 10% of unrelated patients. Genetic testing for RP therefore requires screening for a group of genes. High-throughput and automated sequence detection technologies are essential. Due to the complexity in phenotype and genetics, and the fact that RP is untreatable, genetic testing for presymptomatic diagnosis of RP is controversial. Meanwhile, new genes are still to be identified, mostly by family linkage and sib-pair analysis. Research on gene therapy for RP requires information on gene mutations causative of RP.

Eye Proteins↗

PubMed2005

Cardiovascular risk-associated allele frequencies for 15 genes in healthy elderly French and Chinese.

In order to investigate possible ethnic differences in genetic and environmental determinants, we investigated several cardiovascular disease-associated genetic variations in successful ageing populations of France (Nancy) and China (Hong Kong). Allelic frequencies of these genetic variations were compared between healthy elderly Chinese (n=103) and French populations (n=100). A multi-locus assay was used to genotype 15 genes for 29 biallelic sites, genes implicated in lipid and homocysteine metabolism, thrombosis, leukocyte adhesion, and blood pressure regulation. For most of the candidate markers within lipid metabolism genes, the less frequent alleles were more common in the Chinese population compared with the French population, while the less frequent alleles of the majority of the other markers were detected only or more commonly in the French population. In conclusion, polymorphisms in 13 genes exhibited statistically significant differences in allelic frequencies between the two populations. Since the two populations were selected as examples of successful ageing, we could hypothesise that genetic factors that could play a role in a successful ageing process may be different between the two populations.

Aged↗

PubMed2005

Genetic markers for retinitis pigmentosa.

OBJECTIVE: To review recent advances in the molecular genetics of retinitis pigmentosa with emphasis on the development of genetic markers that aids diagnosis and prognosis. DATA SOURCES AND EXTRACTION: Literature search of MEDLINE from 1988 to 2005 using the following key words: 'retinitis pigmentosa', 'rhodopsin', 'RP1', 'RPGR', and 'genetic counseling'. References of two genes--RHO and RP1--causing retinitis pigmentosa in the Chinese population were reviewed. STUDY SELECTION: Literature and data related to genetic markers for retinitis pigmentosa. DATA SYNTHESIS: The genetics of retinitis pigmentosa is complex. It can be sporadic or familial, with heterogeneous transmission modes. Retinitis pigmentosa is associated with nearly 40 chromosomal loci, where 32 candidate genes have been identified. A large number of mutations are known to cause retinitis pigmentosa. But no single mutation alone accounts for more than 10% of unrelated retinitis pigmentosa patients. Genetic tests for retinitis pigmentosa require screening for a consort of mutations in a large number of genes. High throughput screening technology such as denaturing high performance liquid chromatography and automated DNA sequencing should make such tests feasible. CONCLUSIONS: Rapid developments in the understanding of the genetics of retinitis pigmentosa have helped to establish genetic tests of clinical value. The complex mode of inheritance nonetheless makes genetic counselling difficult, even in the presence of positive genetic screening results.

Chromosome Mapping↗

PubMed2004

Treatment results of endometrial carcinoma with positive peritoneal washing, adnexal involvement and serosal involvement.

AIMS: To review the treatment results of patients with endometrial carcinoma having positive peritoneal washing (PPW), adnexal involvement, uterine serosal involvement, or all three. MATERIALS AND METHODS: The treatment records of patients who had undergone primary surgery for endometrial cancer without distant metastasis during 1990--2001 at the Department of Clinical Oncology, Tuen Mun Hospital, Hong Kong, were reviewed. Thirty-five patients were found to have involvement of positive PPW, adnexal involvement, uterine serosal involvement, or all three. Seven (20%) of them had gross or microscopic lymph-node metastasis. Thirty-three (94.3%) patients received adjuvant radiotherapy (28 whole-pelvic irradiation [WPI]; five abdominal radiotherapy [WART]). Two patients with solitary ovarian metastasis received chemotherapy, and one with isolated PPW also received adjuvant hormonal therapy. The median follow-up was 50.4 months (range 2.4-151.2 months). Multivariate analysis was carried out using the Cox regression proportional hazards model. RESULTS: Among the 28 patients with clinical or pathological node-negative disease (International Federation of Gynecology and Obstetrics [FIGO] stage IIIA), only two patients with solitary ovarian metastases developed recurrence. The 5-year actuarial disease-free survival (DFS) rates for the whole group and patients without lymph-node involvement were 77.9% and 91.7%, respectively. Five out of the seven patients with lymph-node involvement developed recurrences. Univariate analysis showed that lymph-node involvement (P < 0.0001) and high-grade disease (P = 0.011) were the significant poor prognostic factors. Multivariate analysis showed that lymph-node involvement was the only significant poor prognostic factor to predict poor 5-year DFS (P = 0.0001). Only one patient (3.7%) who had received WART developed grade 4 toxicity. CONCLUSIONS: This study showed that good treatment results could be obtained from patients with stage IIIA endometrial carcinoma without clinical or pathological lymph-node involvement after adjuvant radiotherapy, with acceptable late side-effects. The relative prognostic importance of individual IIIA involvement and the optimal adjuvant treatment remain to be determined.

Adult↗

PubMed2004

Use of fasting urinary methylmalonic acid to screen for metabolic vitamin B12 deficiency in older persons.

OBJECTIVES: We sought to determine the cutoffs of fasting urinary methylmalonic acid (MMA) indicating elevated and mildly elevated serum MMA concentrations in older persons. METHODS: We studied 113 female Chinese vegetarians older than 55 y with normal renal function. Fasting serum samples were obtained for measurement of vitamin B12, MMA, and folate and tests of renal function. A fasting urine sample was collected for MMA measurement by the stable-isotope dilution method. The correlation between serum and urinary MMA levels was examined. The optimal cutoffs of urinary MMA for predicting elevated and mildly elevated serum MMA were estimated by use of receiver operating characteristic curves. RESULTS: Fasting urinary and serum MMA levels were linearly correlated. Pearson's correlation coefficient was 0.94. The cutoff of fasting urinary MMA of 2 microM/mM of creatinine had a sensitivity of 79%, a specificity of 85%, and a positive predictive value of 93% for elevated serum MMA (> 0.4 microM/L). A cutoff of 1.5 microM/mM of creatinine had a sensitivity of 86%, a specificity of 85%, and a positive predictive value of 95% for mildly elevated serum MMA (> 0.3 microM/L). Both cutoffs had high positive predictive values for subnormal vitamin B12 concentrations. CONCLUSION: Overnight fasting urinary MMA concentrations have a strong linear relation to serum MMA in older vegetarians without renal impairment. Urinary MMA is potentially useful as a screening tool for metabolic vitamin B12 deficiency in older persons.

Aging↗

PubMed2004

An in vitro study on the compatibility and precipitation of a combination of ciprofloxacin and vancomycin in human vitreous.

AIMS: To investigate the precipitation process of a mixture of vancomycin and ciprofloxacin by equilibrium dialysis and its subsequent effect on the level of available free antibiotics. METHODS: Concentrations of vancomycin and ciprofloxacin in an equilibrium dialysis chamber were measured during the equilibrium process by high performance liquid chromatography and fluorescence polarisation immunoassay. Normal saline (NS), balanced salt solution plus (BSS Plus), and vitreous were used separately as the medium of dialysis. RESULTS: Precipitation of ciprofloxacin occurred on incubation at 37 degrees C. It formed precipitate on its own or when mixed with vancomycin in all the three media of NS, BSS Plus, and vitreous. There was more precipitation at higher initial ciprofloxacin concentrations; at 25.0 mg/l about 75% free drug in BSS Plus was lost after 72 hours. The extent of precipitation was similar in both NS and BSS Plus. In the dialysis chambers, 20 mg/l ciprofloxacin dialysed against 125 mg/l vancomycin was reduced to a concentration about 5.0 mg/l after 168 hours. Precipitation of vancomycin was negligible. Ciprofloxacin precipitated in vitreous at body temperature, irrespective of the presence of vancomycin. Even after precipitation, the resultant concentration of ciprofloxacin was still higher than the MIC(90) of the drug against most Gram negative organisms. CONCLUSIONS: Based on this in vitro study, ciprofloxacin precipitated in vitreous at body temperature, irrespective of the presence of vancomycin or the medium for intravitreal injection. The resultant amount of ciprofloxacin was still higher than the MIC(90) of the drug against most Gram negative organisms after precipitation. The authors suggest ciprofloxacin in place of ceftazidime when used in combination with vancomycin for treatment of infective endophthalmitis.

Aged↗

PubMed2004

Effects of trypan blue on cell viability and gene expression in human retinal pigment epithelial cells.

AIM: To evaluate the effects of trypan blue on cell viability and gene expression in human retinal pigment epithelial (RPE) cells. METHODS: Three concentrations (0.06 mg/ml, 0.6 mg/ml, and 4 mg/ml) of trypan blue were applied to human ARPE19 cells for 1 minute. Cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. RPE cells were sampled daily for 6 consecutive days to assess the effects of trypan blue on cell viability. The effects of trypan blue on the expression of apoptosis related and cell cycle arrest gene expressions including c-fos, c-jun, p53, and p21 were performed using reverse transcription-polymerase chain reaction and immunostaining. RESULTS: The MTT assay showed a concentration dependent suppression effect of trypan blue on cell viability, with higher reduction in the 0.6 mg/ml and 4 mg/ml trypan blue treated groups. No significant change in the expression of c-fos and c-jun was found with all three concentrations of trypan blue. An increase in p53 expression was found in the 4 mg/ml trypan blue treated group at 10-30 minutes after trypan blue application. Immunostaining showed a mild, albeit insignificant, increase of p53 expression in the RPE cells. No significant increase in p21 expression was observed in the 0.06 mg/ml trypan blue treated group but there were significant increases in p21 expression in both the 0.6 mg/ml (p = 0.032) and the 4 mg/ml (p = 0.025) treated groups. CONCLUSIONS: Trypan blue may lead to toxicity on cultured RPE cells as indicated by the reduction in cell viability and changes in the expression of apoptosis related and cell cycle arrest genes at higher concentrations. The application of 0.06 mg/ml trypan blue for 1 minute appeared to have no significant effect on cultured RPE.

Apoptosis↗

PubMed2003

Laparoscopy for the treatment of women with endometrial cancer.

OBJECTIVE: To evaluate the use of a laparoscopic approach for the management of endometrial cancer. DESIGN: Retrospective study. SETTING: Regional hospital, Hong Kong. SUBJECTS AND METHODS: Individual medical records of patients with preoperative histological diagnosis of endometrial carcinoma from January 2000 to December 2001 were reviewed and the data analysed. MAIN OUTCOME MEASURES: Success of laparoscopic-assisted surgical staging, intra-operative and postoperative morbidity, and length of hospital stay. RESULTS: Laparoscopic surgery was successful for 93.3% (28 of 30) patients. Two patients were converted to laparotomy. The mean operating time was 102 minutes (standard deviation, 16 minutes) and the mean operative blood loss was 280 mL (standard deviation, 137 mL). The mean hospital stay was 5 days (standard deviation, 2.3 days). The intra-operative and postoperative complication rate was 16.7%, including vaginal tear, injury to the inferior epigastric vessel, lymphocyst, and pulmonary embolism. CONCLUSION: This study illustrated that a laparoscopic approach is feasible for endometrial cancer surgery and may be considered as the primary treatment modality in skilled hands. This approach should be offered to women with endometrial cancer without contraindications for laparoscopic surgery if experienced endoscopic surgeons are available. Prophylaxis for venous thromboembolism and the use of retroperitoneal drainage may be helpful in decreasing the perioperative morbidity.

Abdominal Abscess↗

PubMed2002

Independent effect of vitamin B12 deficiency on hematological status in older Chinese vegetarian women.

We have examined the independent effect of vitamin B(12) deficiency on hematological indices in older Chinese vegetarian women using a cross-sectional study design: 119 women older than 55 years who had been vegetarian for more than 3 years were studied. Fasting blood samples were taken for complete blood count, serum iron, total serum iron binding capacity, serum iron saturation, serum vitamin B(12), serum folate, serum methylmalonic acid levels (MMA), and renal function test. Subjects with iron deficiency (iron saturation <15%) and those with serum creatinine >150 mmol/L were excluded. The prevalence of definite vitamin B(12) deficiency (vitamin B(12) level < 150 pmol/L and MMA >or= 0.4 micromol/L) was 42%. Another 32.8% had possible vitamin B(12) deficiency (either criterion). The prevalence of iron deficiency was 10%. After exclusions, 96 subjects were further analyzed. Vitamin B(12) deficiency defined by serum vitamin B(12) and MMA was associated with a decrease in hemoglobin concentrations by up to 0.9 g/dL, but it was not associated with an increase in mean corpuscular volume (MCV). Serum MMA but not vitamin B(12) levels correlated inversely with hemoglobin and platelet counts and positively with MCV, after adjustment of confounding factors. However, the percentage of subjects with anemia did not increase significantly until serum MMA became >1.0 micromol/L. In conclusion, vitamin B(12) deficiency was associated with a significant decrease in hemoglobin concentration. However, anemia associated with vitamin B(12) deficiency was seldom macrocytic. We recommend that older vegetarians should be given vitamin B(12) supplements routinely.

Aged↗

PubMed2002

Recurrent BRCA1 and BRCA2 germline mutations in ovarian cancer: a founder mutation of BRCA1 identified in the Chinese population.

Previous mutational analysis for BRCA gene mutations in sporadic ovarian cancer occurring in Chinese patients in Hong Kong identified six germline BRCA1 mutations and one germline BRCA2 mutation, six of which were novel (Khoo et al., 2000). Knowledge of BRCA gene mutations in the Chinese population is relatively scant. In this study, we focussed on whether any of these mutations could be recurrent in our Chinese population, making use of archival paraffin embedded tissue. A consecutive series of 214 ovarian cancer cases, half of Southern Chinese origin from Hong Kong whilst the other half of Northern Chinese origin from Beijing were used for the study. We identified one further novel mutation, 1081delG, in BRCA1. This was found to occur in two unrelated individuals with shared haplotype as revealed by allelotype analysis, thus demonstrating founder effect. Two other recurrent mutations were also identified, the 2371-2372delTG mutation in BRCA1 and the 3337C>T mutation in BRCA2 recurring in two and three unrelated individuals respectively, giving an overall prevalence 4.7% of recurrent BRCA mutations in ovarian cancer in the Southern Chinese population. Most importantly, all our recurrent mutation carriers were identified from Southern Chinese patients from Hong Kong whilst such mutations were absent in samples from the Northern Chinese. Our findings indicate possible heterogeneity in the BRCA genotype between Northern and Southern Chinese. The identification of a founder mutation and two recurrent mutations moreover, has important implications towards screening strategies for breast and ovarian cancer among Chinese of southern ancestral origin who are now dispersed throughout the world.

Adult↗

PubMed2002

Effects of high inspired oxygen fraction during elective caesarean section under spinal anaesthesia on maternal and fetal oxygenation and lipid peroxidation.

BACKGROUND: Oxygen supplementation is given routinely to parturients undergoing Caesarean section under regional anaesthesia. While the aim is to improve fetal oxygenation, inspiring a high oxygen fraction (FIO2) can also increase free radical activity and lipid peroxidation in both the mother and baby. In this prospective, randomized, double-blind study, we investigated the effect of high inspired oxygen fraction (FIO2) on maternal and fetal oxygenation and oxygen free radical activity in parturients having Caesarean section under spinal anaesthesia. METHODS: Forty-four healthy parturients were randomized to breathe either 21% (air group) or 60% oxygen (oxygen group) intraoperatively via a ventimask. Maternal arterial blood was collected at 5-min intervals from baseline until delivery, and umbilical arterial and venous blood was collected at delivery. We measured blood gases and the products of lipid peroxidation (8-isoprostane, malondialdehyde (MDA), hydroperoxide (OHP)) and purine metabolites. RESULTS: At delivery, the oxygen group had greater maternal arterial PO2 [mean 30.0 (SD 6.3) vs 14.2 (1.9) kPa; mean difference 15.8 kPa, 95% confidence interval 12.9-18.7 kPa, P<0.001] and greater umbilical venous PO2 [4.8 (1.0) vs 4.0 (1.4) kPa; mean difference 0.8 kPa, 95% confidence interval 0.0-1.5 kPa, P=0.04] compared with the air group. Maternal and umbilical plasma concentrations of lipid peroxides (8-isoprostane, MDA, OHP) were greater in the oxygen group than in the air group (P<0.05). CONCLUSIONS: We conclude that breathing high FIO2 modestly increased fetal oxygenation but caused a concomitant increase in oxygen free radical activity in both mother and fetus.

Adult↗

PubMed2002

Bilateral congenital corneal keloids and anterior segment mesenchymal dysgenesis in a case of Rubinstein-Taybi syndrome.

PURPOSE: To report the unusual association of bilateral corneal keloids and anterior segment mesenchymal dysgenesis in a child with Rubinstein-Taybi syndrome. METHODS: Case report of a 2-year-old boy. RESULTS: Excision of the epicorneal mass in the right eye was followed by recurrence of the lesion. Multiple penetrating keratoplasties were unsuccessful in reconstructing the anterior segment because of recurrent corneal epithelial breakdown, suggesting limbal stem cell insufficiency. Histopathology and electron microscopy of the excised mass lesion showed features typical of a corneal keloid: thickened keratinized epithelium, absent Bowman's layer, and fibrovascular hyperplasia, with haphazard orientation of the collagen lamellae. Ultrasound biomicroscopy and intraoperative findings suggested a diagnosis of Peter anomaly, but genetic analysis did not show a PAX6 mutation. CONCLUSION: The findings in our patient add to the spectrum of ocular changes described in Rubinstein-Taybi syndrome and confirm earlier reports of poor ocular prognosis in corneal keloids and Rubinstein-Taybi syndrome.

Anterior Eye Segment↗