Tyrosinase gene (TYR) mutations in Chinese patients with oculocutaneous albinism type 1

Background: To identify the sequence variants of the tyrosinase (TYR) gene in Chinese families with oculocutaneous albinism. Methods: Three families with oculocutaneous albinism type 1 and 95 unrelated healthy Chinese individuals with normal pigmentation were screened for mutations in the TYR gene by direct sequencing. Computational algorithms were used to characterize the biological significance of the mutants. Results: Four previously reported mutations (R299C, R299H, W400L and frame‐shift c.930insC) and one novel mutation (F214del) were identified, and probands had homozygous or compound heterozygous TYR mutant alleles. None of the mutants were identified among the 95 normal control subjects. Computational analysis predicted that the R299C mutant inactivates the tyrosinase enzyme by misfolding of protein tertiary structure and/or retention of the misfolded tyrosinase within the endoplasmic reticulum, and F214del causes dysfunction of tyrosine enzyme by affecting the copper binding sites and altering substrate orientation and electronic transfers during catalytic reactions for melanosynthesis. Conclusion: We have identified five different TYR mutations, including one novel mutation, which caused oculocutaneous albinism type 1 in Chinese. Further analysis of the patients will be useful to determine the effects of these mutations on the tyrosinase activities.     

Contribution of SNRNP200 sequence variations to retinitis pigmentosa

Purpose

Mutations in the SNRNP200 gene have been reported to cause autosomal dominant retinitis pigmentosa (adRP). In this study, we evaluate the mutation profile of SNRNP200 in a cohort of southern Chinese RP patients.

Methods

Twenty adRP patients from 11 families and 165 index patients with non-syndromic RP with mixed inheritance patterns were screened for mutations in the mutation hotspots of SNRNP200. These included exons 12–16, 22–32, and 38–45, which covered the two helicase ATP-binding domains in DEAD-box and two sec-63 domains. The targeted regions were amplified by polymerase chain reaction and analyzed by direct DNA sequencing, followed by in silico analyses.

Results

Totally 26 variants were identified, 18 of which were novel. Three non-synonymous variants (p.C502R, p.R1779H and p.I698V) were found exclusively in patients. Two of them, p.C502R and p.R1779H, were each identified in one simplex RP patient, whereas p.I698V occurred in one patient with unknown inheritance pattern. All three residues are highly conserved in SNRNP200 orthologs. Nevertheless, only p.C502R and p.R1779H were predicted to affect protein function by in silico analyses, suggesting these two variants are likely to be disease-causing mutations. Notably, all mutations previously identified in other study populations were not detected in this study.

Conclusions

Our results reveal a distinct mutation profile of the SNRNP200 gene in a southern Chinese cohort of RP patients. The identification of two novel candidate mutations in two respective patients affirmed that SNRNP200 contributes to a proportion of overall RP.     

Hypoglycaemic activity of commelina africana and ageratum conyzoides in relation to their mineral composition

Background

Many plants with antidiabetic properties probably act in part through their content of fibre, vitamins, bioactive or mineral content

Objectives

This study investigated the mineral, proximate, phytochemical compositions and hypoglycaemic effect of Commelina africana and Ageratum conyzoides extracts in diabetic rats, and the likely relationship between this property and the mineral, proximate and phytochemical compositions of the plants.

Methods

The plants were subjected to mineral, proximate composition and phytochemical analysis. Attempt was made to see (if any) the relationship between the hypoglycaemic effect and the mineral, proximate compositions and phytochemistry of the plants. Alloxan-induced diabetic animals were administered 500mg/kg body weight aqueous extracts of the plants and glibenclamide as the reference hypoglycaemic agent.

Results

Aqueous extract of Ageratum conyzoides reduced fasting blood glucose of experimental animals by 39.1% while Commelina africana reduced the same by 78.0%. Alkaloids, cardenolides, saponins, and tannins were detected in both plants. Anthraquinones was absent in C. africana but a trace of it was detected in A. conyzoides. The hypoglycaemic effect of Commelina africana was comparable with the reference hypoglycaemic agent. Ageratum conyzoides showed comparably weaker hypoglycaemic effect than exhibited by reference hypoglycaemic agent. Comparatively, Commelina africana had higher mineral concentrations (except Na) than Ageratum conyzoides.

Conclusions

Plants'' extracts minerals (magnesium, potassium and iron) and bioactive components (alkaloids and cardenolides) seemingly enhanced their hypoglycaemic effect. Furthermore, these minerals, alkaloids and cardenolides could be helpful in ameliorating complications of diabetes like hypertension and cardiovascular disease.     

Antimicrobial and fluoride release capacity of orthodontic bonding materials

Objective

The aim of this study was to evaluate the antimicrobial and fluoride releasing capacity of 3 bonding materials.

Material and Methods

Thirty nine specimens with standardized surface smoothness and dimensions were prepared. The antimicrobial capacity of the materials against S. mutans, L. casei and C. albicans was evaluated by determining the percentage of growth inhibition of these microorganisms in an inoculated medium, obtained by optical density readouts on a spectrophotometer. The potential to interfere in microbial growth on the surface of the studied materials was observed by means of scanning electron microscopy (SEM). The fluoride release capacity in ultrapure water for 14 days was analyzed by means of ion chromatography.

Results

The PLUS group presented the highest percentage of microbial inhibition and the most contamination-free surface. The FUJI group presented the best fluoride release capacity.

Conclusions

The Transbond^TM Plus Color Change was the one that presented the best general behavior considering the evaluated aspects.     

The ML Cu250; clinical experience in Belgium and The Netherlands

Summary. The ML Cu250, a copper-wired intrauterine contraceptive device, was inserted in 5736 women, at interval or immediately after delivery of the placenta. Forty-eight months after insertion, the data covering 196214 woman-months were computerized and then analysed according to the life-table method. Interval insertion was more effective than postplacental insertion. In nulligravidas interval insertion did not increase the removal rates for other medical reasons (including pelvic inflammatory disease), but expulsion rates were higher relative to the entire group (a variety of parities).     

TWO-LEVEL INTERVERTEBRAL DISC HERNIATION IN AN ADOLESCENT

SUMMARY A two-level intervertebral disc prolapse is a rare circumstance in adolescents. We describe the case of a 19-year-old man who suffered a deceleration trauma and developed simultaneous large intervertebral disc herniations at L4/5 and L5/S1. The aetiology is discussed and, in accordance with the current literature, it is pointed out that clinical findings due to intervertebral disc herniations in young people do not necessarily correspond with the extent of the disease.     

Blood lead, calcium, and phosphorus in women with preeclampsia in Edo State, Nigeria

The authors investigated the effect of blood lead (BPb) and its relationship with calcium and phosphorus in the development of preeclampsia in Nigeria. Blood samples were collected from 59 preclamptics, 150 normal pregnant, and 122 nonpregnant women. Blood lead and serum Ca and P were determined. Blood lead was significantly higher (p < .001), whereas serum Ca and P were significantly lower (p < .001) in preclamptics than in normal pregnant women (60.2 ± 12.8 vs 26.3 ± 8.0 μg/dL for Pb, 1.39 ± 0.33 vs 2.03 ± 0.22 mmol/L for Ca, and 0.76 ± 0.10 vs 0.99 ± 0.13 mmol/L for P, respectively). There was significant increase (p < .05) in BPb and decreases (p < .01) in serum Ca and P in pregnant women than in nonpregnant women (35.7 ± 18.0 vs 13.1 ± 6.4 μg/dL for Pb, 1.85 ± 0.33 vs 2.33 ± 0.20 mmol/L for Ca, and 0.93 ± 0.38 vs 1.24 ± 0.26 mmol/L for P). Also, BPb was negatively correlated with serum Ca and, P, and positively correlated with systolic and diastolic blood pressures in pregnancy (r = -.804 for Ca, r = -.728 for P, r = .908 for SBP, and r = .842 for DBP) and preeclampsia (p < .01). It appears that increase in blood lead, which parallels decreases in serum calcium and phosphorus, may be related to the development and progression of preeclampsia in this environment.