Riboflavin

Seventeen cis-dominant mutations leading to riboflavin overproduction in Bacillus subtilis were localized to the region between nucleotides + 37 and + 159 relative to the transcription initiation site of the riboflavin operon. This region displays an unusual structure for regulatory sequences. The main part of it represents clusters of A/T and G/Grich sequences that symmetrically blank a short inverted repeat.

Trauma transfusion packages for hemorrhage control consist of red blood cells, plasma, and platelets at a set ratio. Although pathogen reduction improves the transfusion safety of platelet and plasma units, there is an associated reduction in quality. This study aimed to investigate the impact of riboflavin/ultraviolet light-treated plasma or platelets in transfusion trauma packages composed of red blood cell, plasma, and platelet units in a ratio of 1:1:1 in vitro by modeling transfusion scenarios for trauma patients and assessing function by rotational thromboelastometry. Pathogen-reduced or untreated plasma and buffy coat platelet concentrate units produced in plasma were used in different combinations with red blood cells in trauma transfusion packages. After reconstitution of these packages with hemodiluted blood, the hemostatic functionality was analyzed by rotational thromboelastometry. Hemostatic profiles of pathogen-inactivated buffy coat platelet concentrate and plasma ind...

We have complemented the riboB2 mutation of Aspergillus nidulans by transformation with a plasmid library of wild-type (wt) sequences. We have isolated, by marker rescue from a riboB+ transformant, a plasmid that complements riboB2 efficiently. From this plasmid we have subcloned an A. nidulans sequence that complements riboB2 efficiently and that integrates by homologous recombination at a site closely linked to the riboB locus. We conclude that this sequence contains the wt riboB+ allele.

Two experiments were conducted to evaluate the response of sows to high levels of dietary riboflavin. Responses evaluated were erythrocyte glutathione reductase activity coefficient (EGRAC, a biochemical indicator of riboflavin status) and reproductive performance. In Exp. 1, eight sows were fed diets either slightly deficient or superadequate in riboflavin throughout a reproductive cycle, beginning in midgestation. The EGRAC values confirmed the slight deficiency (P < .01) but did not clearly show a time when the sow is most likely to be deficient in riboflavin. In Exp. 2, 118 sows at two farms were fed diets providing 10 (control, 1.4 times the NRC [1988] requirement estimate), 60, 110, or 160 mg of riboflavin/d for 21 d beginning at breeding, and the control level through the remainder of the reproductive cycle. The percentage of sows farrowing tended to be lower (P < .10) for the control sows than for sows fed the other treatments (66.7, 85.7, 93.3, and 86.7% for 10, 60, 1...

Cupric chloride-triphenylphosphine complex reacts with riboflavin in alkaline medium giving an orange color having maximum absorbance at 460–465 nm and 1μg/ml as visual limit of identification. This color reaction has been utilized for the spectrophotometric determination of riboflavin from pharmaceutical preparations in minute quantities. The reaction is specific for riboflavin and does not require stringent conditions. The maximum tolerable amount of other vitamins, sugars and amino acids during determination of riboflavin is reported. Der Kupfer(II)-chlorid-Triphenylphosphin-Komplex reagiert mit Riboflavin in alkalischem Medium unter Orangefärbung mit einem Absorptions-maximum bei 460 bis 465 nm. Die Empfindlichkeitsgrenze beträgt 1μg/ml. Diese Farbreaktion wurde zur spektrophotometrischen Bestimmung geringer Mengen Riboflavin in pharmazeutischen Präparaten herangezogen. Sie ist spezifisch für Riboflavin und nicht an stringente Versuchsbedingungen gebunden. Die maximale Menge anderer Vitamine, Zucker und Aminosäuren, die die Reaktion nicht stören, wurde angegeben.

Riboflavin is a potent photosensitizer as well as part of the vitamin B complex. Recently we demonstrated that the products generated by irradiation of riboflavin have potential as anti-leukaemic therapy. The possible action, however, of the riboflavin photoproducts in solid cancers has not been addressed. Hence, we investigated the effects of irradiated riboflavin on androgen-independent human prostate cancer cells (PC3), a known model for solid tumour cells with an exceptional resistance to therapy. Our results show that riboflavin photoproducts are cytotoxic to these cells in a FasL-Fas-dependent manner. Furthermore, irradiated riboflavin inhibited matrix-degrading proteases, caused downregulation of VEGF and upregulation of TIMP1 suggesting anti-metastatic potential. Together, these results show that the anti-neoplastic action of riboflavin photoproducts is not limited to haematological malignancies, warranting clinical studies in solid tumours.

Methylenetetrahydrofolate reductase (MTHFR) is a critical folate-metabolising enzyme which requires riboflavin as its co-factor. A common polymorphism (677C→T) in the MTHFR gene results in reduced MTHFR activity in vivo which in turn leads to impaired folate metabolism and elevated homocysteine concentrations. Homozygosity for this polymorphism (TT genotype) is associated with an increased risk of a number of conditions including heart disease and stroke, but there is considerable variability in the extent of excess risk in various reports. The present review will explore the evidence which supports a role for this polymorphism as a risk factor for a number of adverse health outcomes, and the potential modulating roles for B-vitamins in alleviating disease risk. The evidence is convincing in the case which links this polymorphism with hypertension and hypertensive disorders of pregnancy, particularly preeclampsia. Furthermore, elevated blood pressure was found to be highly responsiv...

Objective: Riboflavin UVA (collagen crosslinking [CXL]) treatment for keratoconus is a method for stabilizing or improving corneal properties. Our aim was to evaluate changes in corneal topography indices after CXL. Methods: A total of 38 eyes of 25 patients (mean age 29.36 ± 9.7 years) were treated with CXL technique. The follow-up period was 36 months. Slit-lamp examination, visual acuity tests, and pachymetry measurements were performed; in order to obtain the following numerical data, corneal topography (TMS-4; Tomey) was used: simulated keratometry (K1, K2), CYL (cylinder value), SAI (surface asymmetry index), IAI (irregular astigmatism index), SRI (surface regulatory index), ACP (average corneal power), and CEI (corneal eccentricity index). Treatments were performed with In-Pro CCL- Lix (Germany) equipment. Results: The values of mean K1 (p = 0.82), cylinder (p = 0.73), SAI (p = 0.99), IAI (p = 0.82), SRI (p = 0.73), ACP (p = 0.73), K2 (p = 0.8), and CEI (p = 0.99) showed no s...