Investigation of genetic diversity using molecular and biochemical markers associated with powdery mildew resistance in different flax (Linum usitatissimum L.) genotypes.

Under greenhouse conditions, the resistance of 18 different genotypes of flax to powdery mildew was evaluated. To investigate genetic diversity and identify the molecular and biochemical markers linked to powdery mildew resistance in the tested genotypes, two molecular marker systems-start codon targeted (SCoT) and inter-simple sequence repeat (ISSR)-as well as a biochemical marker (protein profiles, antioxidant enzyme activity, and secondary metabolites) were used. Based on the results, the genotypes were classified into four categories: highly susceptible, susceptible, moderately susceptible, and moderately resistant. The genotypes differed significantly in powdery mildew severity: Polk had a severity of 92.03% and Leona had a severity of 18.10%. Compared to the other genotypes, the moderately resistant genotypes had higher levels of flavonoids, antioxidant enzymes, phenolics, and straw yield; nevertheless, their hydrogen peroxide and malondialdehyde levels were lower. Protein profiles revealed 93.75% polymorphism, although the ISSR marker displayed more polymorphism (78.4%) than the SCoT marker (59.7%). Specific molecular and biochemical markers associated with powdery mildew resistance were identified. The 18 genotypes of flax were divided into two major clusters by the dendrogram based on the combined data of molecular markers. The first main cluster included Leona (genotype number 7), considered moderate resistance to powdery mildew and a separate phenetic line. The second main cluster included the other 17 genotypes, which are grouped together in a sub-cluster. This means that, besides SCoT, ISSR markers can be a useful supplementary technique for molecular flax characterization and for identifying genetic associations between flax genotypes under powdery mildew infection.

The efficacy of chemical inducers and fungicides in controlling tomato root rot disease caused by Rhizoctoniasolani.

Chitosan is an environmentally friendly natural substance that is used in crop disease management as an alternative to chemical pesticides. A significant issue restricting output in Egypt is root rot, which is a disease, caused by Rhizoctonia solani. Therefore, a greenhouse experiment was conducted to assess the effects of R. solani on 60-day-old tomato plants under fungal infection and to determine the antifungal activity of chitosan and Rizolax T fungicide against the pathogenic fungus. The findings demonstrated that 4 g/L of chitosan seed application completely obstructed the radial mycelial growth of R. solani and decreased the disease severity. Pathogenic infection significantly decreased morphological characteristics and total chlorophyll but significantly increased carotenoid, total thiol, non-protein thiol, protein thiol, antioxidant enzymes, oxidative stress, total phenolic, total flavonoid, and isoflavone compared to healthy plants. Tomato plants treated with chitosan exhibited lower rates of oxidative stress, but higher levels of all previously mentioned parameters compared to untreated infected plants. The number and molecular mass of protein banding patterns varied in all treated tomato plants as compared to the healthy control. There are 42 bands in the treatments, and their polymorphism rate is 69.55%. Moreover, the number and density of α- and ß-esterase, and peroxidase isozymes in treated tomato plants exhibited varied responses. Moreover, in treated and control plants, chitosan treatment raised the expression levels of phenylalanine ammonia-lyase, pathogenesis-related protein-1, ß-1,3-glucanases and chitinase. In conclusions, chitosan reduces R. solani infection by controlling the biochemical and molecular mechanisms in tomato plants during infection.

Agro-morphological, biochemical, and molecular markers of barley genotypes grown under salinity stress conditions.

The aim of this study was to evaluate the impact of salt stress on morphological, yield, biochemical, and molecular attributes of different barley genotypes. Ten genotypes were cultivated at Fayoum Research Station, El-Fayoum Governorate, Egypt, during two seasons (2020-2021 and 2021-2022), and they were exposed to two different salt concentrations (tap water as a control and 8000 ppm). The results showed that genotypes and salt stress had a significant impact on all morphological and physiological parameters. The morphological parameters (plant height) and yield attributes (spike length, number of grains per spike, and grain yield per plant) of all barley genotypes were significantly decreased under salt stress as compared to control plants. Under salt stress, the total soluble sugars, proline, total phenol, total flavonoid, ascorbic acid, malondialdehyde, hydrogen peroxide, and sodium contents of the shoots of all barley genotypes significantly increased while the potassium content decreased. L1, which is considered a sensitive genotype was more affected by salinity stress than the tolerance genotypes L4, L6, L9, and Giza 138. SDS-PAGE of seed proteins demonstrated high levels of genetic variety with a polymorphism rate of 42.11%. All genotypes evaluated revealed significant variations in the seed protein biochemical markers, with new protein bands appearing and other protein bands disappearing in the protein patterns of genotypes cultivated under various conditions. Two molecular marker techniques (SCoT and ISSR primers) were used in this study. Ten Start Codon Targeted (SCoT) primers exhibited a total of 94 fragments with sizes ranging from 1800 base pairs to 100 base pairs; 29 of them were monomorphic, and 65 bands, with a polymorphism of 62.18%, were polymorphic. These bands contained 21 unique bands (9 positive specific markers and 12 negative specific markers). A total of 54 amplified bands with molecular sizes ranging from 2200 to 200 bp were produced using seven Inter Simple Sequence Repeat (ISSR) primers; 31 of them were monomorphic bands and 23 polymorphic bands had a 40.9% polymorphism. The techniques identified molecular genetic markers associated with salt tolerance in barley crop and successfully marked each genotype with distinct bands. The ten genotypes were sorted into two main groups by the unweighted pair group method of arithmetic averages (UPGMA) cluster analysis based on molecular markers and data at a genetic similarity coefficient level of 0.71.

Green synthesized silver nanoparticles mediated by Fusarium nygamai isolate AJTYC1: characterizations, antioxidant, antimicrobial, anticancer, and photocatalytic activities and cytogenetic effects.

Green biosynthesized nanoparticles have a bright future because they can be produced using a method that is more energy-efficient, cost-effective, repeatable, and environmentally friendly than physical or chemical synthesis. In this study, silver nanoparticles (AgNPs) were produced using the Fusarium nygamai isolate AJTYC1. Several techniques were used to characterize the synthesized AgNPs, including UV-Vis spectroscopy, transmission electron microscope, zeta potential analysis, X-ray diffraction analysis, energy dispersive X-ray, and Fourier transform-infrared spectroscopy. AgNPs showed a distinctive surface plasmon resonance (SPR) peak in the UV-visible range at 310 nm. The morphology of the biosynthesized AgNPs was spherical, and the TEM image shows that they ranged in size from 27.3 to 53.1 nm. The notable peaks of the FT-IR results show the different groups for the alkane, alkynes, cyclic alkenes, carboxylic, aromatic amine, esters, and phenolics. Additionally, the results showed that AgNPs had superior antioxidant activity when compared to ascorbic acid and butylated hydroxytoluene, which is a powerful antioxidant. Additionally, AgNPs have antibacterial action utilizing agar diffusion against gram-positive bacteria, gram-negative bacteria, and antifungal activity. AgNPs' anticancer activity varied depending on the type of cancer it was used to treat, including hepatocellular cancer (HepG2), colorectal carcinoma (HCT116), and breast cancer of the mammary gland (MCF7). The viability of the cancer cell lines was reduced with increasing AgNP concentration. AgNPs also demonstrated promising photocatalytic activity by reducing methylene blue, safranin, crystal violet, and green malachite by 88.3%, 81.5%, 76.4%, and 78.2%, respectively. In addition, AgNPs significantly affected the Allium cepa plant's mitotic index and resulted in chromosomal abnormalities as compared to the control. Thus, the synthesized AgNPs demonstrated an efficient, eco-friendly, and sustainable method for decolorizing dyes as well as antioxidant, antibacterial, antifungal, and anticancer activities. This could be a huge victory in the fight against numerous dynamic diseases and lessen wastewater dye contamination.

Chromatographic Techniques for Assessment of Bisoprolol Fumarate and Perindopril Arginine in Solid Formulations under Various Stress Conditions and Application to Six Sigma, Content Uniformity, and Comparative Dissolution Approaches.

BACKGROUND: Antihypertensives bisoprolol fumarate (BIS) and perindopril arginine (PER) were simultaneously determined in their pure, bulk, and combined tablet dosage form. OBJECTIVE: This study develops a novel, reproducible, and accurate Reversed phase high-performance liquid chromatography (RP-HPLC) and Reversed phase ultra-performance liquid chromatography (RP-UPLC) with photodiode array detection techniques, which were then applied to in vitro dissolution studies. METHODS: The first RP-HPLC method relied on isocratic elution using a mobile phase of methanol-0.05 M phosphate buffer pH 2.6 (1 + 1, by volume), and separation was performed using a Thermo Hypersil C8 column (150 mm × 4.6 mm, 5 µm). Ion-pair UPLC was the second method. An acceptable resolution was achieved using an RP-C18 chromatographic column, Agilent Eclipse (100 × 2.1 mm, 1.7 µm), with a mobile phase containing 0.005 M sodium 1-heptane sulfonate-triethylamine (64 + 1 + 35, by volume), adjusted with phosphoric acid to a pH of 2.0. RP-HPLC used a 1.0 mL/min flow rate, while UPLC used 0.5 mL/min, and the two methods used detection at 210 nm. RESULTS: Calibration curves of BIS and PER were linear for RP-HPLC and RP-UPLC methods at 0.5-15 and 0.5-40 µg/mL, respectively. BIS and PER had RP-UPLC LODs of 0.22 and 0.10 µg/mL, respectively, and LOQs of 0.68 and 0.31 µg/mL, respectively. As a result, the approach has been effectively applied to in vitro dissolution testing for drugs in generic and reference products, showing that the two products are comparable. The Six Sigma approach was implemented to compare the recommended and United States Pharmacopeia (USP) procedures, which both exhibited process capability index (Cpk) >1.33. A content uniformity test demonstrated that the drugs in their dosage form met the acceptance limit (85-115%). The degradation products were reliably distinguished from pure drugs for a range of retention times. CONCLUSION: In their commercial drug product, the proposed method could be used in QC laboratories for concurrent testing, content uniformity, and in vitro dissolution investigations of BIS and PER. The methods were successfully validated per International Council for Harmonisation (ICH) guidelines. HIGHLIGHTS: This study is innovative since it is the first to establish and validate specific and reproducible UPLC and HPLC methods for the concurrent quantitation of the studied drugs in their binary mixture and application to lean Six Sigma, content uniformity, and comparative dissolution approaches.

Prospective Comparison of Subtalar Arthroereisis With Calcaneal Lengthening in the Management of Planovalgus Feet of Ambulatory Children With Spastic Cerebral Palsy?

BACKGROUND: Pes planovalgus (PPV) deformity is common among cerebral palsy (CP) patients. There is no true consensus about the best way of treating this common deformity, especially when surgical interference is required. Treatment options range from orthotics to complex surgical procedures. The purpose of this prospective study was to evaluate and compare the effectiveness of 2 different procedures in the correction of symptomatic flexible PPV in ambulatory CP patients. METHODS: A total of 57 feet in 35 patients were divided into 2 groups: group 1, subtalar arthroereisis group, using the calcaneostop technique; group 2, lateral column lengthening group, using Evans osteotomy. Patients were assessed clinically by the clinical score proposed by Yoo et al and radiologically by measuring 7 weight-bearing angles, both preoperatively and 12 months postoperatively. Patients' (or parents') satisfaction and their tolerance to braces or shoes were assessed 12 months after surgery as secondary outcome parameters. RESULTS: There was a statistically significant improvement in both primary and secondary outcome parameters after both procedures in comparison to the preoperative parameters. No statistically significant differences were observed between the 2 groups regarding the outcomes of both procedures except for the greater power of arthroereisis in the correction of hindfoot valgus, which was statistically significant both clinically and radiographically. CONCLUSION: Both procedures are valid options for the surgical management of PPV in ambulatory children with spastic CP. The less-invasive nature and lower potential morbidity suggest that judicious use of arthroereisis is appropriate for some patients, especially in the context of single-event multilevel surgery. LEVELS OF EVIDENCE: Level II: Prospective, comparative study.

Radiological outcome of calcaneo-cuboid-cuneiform osteotomies for planovalgus feet in cerebral palsy children: Relationship with pedobarography.

BACKGROUND: Calcaneo-cuboid-cuneiform (triple C) osteotomies correct all levels of deformity of flexible planovalgus feet (PVF) in patients with cerebral palsy (CP). The objective was assessing short term results and the hypothesis was that static pedobarography correlates with radiological parameters as outcome measures. METHODS: A prospective case series of consecutive skeletally immature ambulatory spastic CP patients above the age of 4 years who underwent triple C for PVF. Assessment was done using static pedobarography and standing dorsoplantar (DP) and lateral radiographs. The calcaneal pitch, lateral talocalcaneal, lateral and DP talo-first metatarsal, and DP talonavicular coverage angles were measured. RESULTS: Eighteen feet (12 patients) were analyzed. Postoperative changes in lateral and DP talo-first metatarsal, and DP talonavicular coverage angles were statistically significant (P-value=0 with paired T-test). Post operative foot pressure changes were significant and highest in mid-foot. Both outcomes were related together with a p-value of 1 using McNemar test. CONCLUSIONS: The triple C and associated soft tissue procedures reliably corrected PVF deformities. Static pedobarography can be used for postoperative assessment of adequate correction.

MicroRNA-122 as a Novel Non-Invasive Marker of Liver Fibrosis in Hepatitis C Virus Patients.

BACKGROUND: Noninvasive evaluation of hepatic fibrosis is a growing scientific effort in medicine and is of particular interest as early diagnosis is important for the timely prevention and treatment of liver fibrosis and cirrhosis. Non-invasive markers of liver fibrosis have recently been developed as an alternative to liver biopsy. Aim of the work: The aim of this study was to assess the diagnostic value of serum microRNA 122 in Egyptian chronic hepatitis C virus infected patients. This may be a useful tool as a non invasive diagnostic test to detect early stages of fibrosis in comparison to 4 non invasive indexes (APRI, Forns, FIB-4, and FI) vs. control and their ability to differentiate between mild and moderate fibrosis stages. METHODS: This study was conducted on 40 chronic hepatitis C patients diagnosed by liver biopsy and PCR and 20 apparently healthy volunteers who served as control group (III). Liver fibrosis was staged according to the METAVIR scoring system and consequently patients were classified in two groups of liver fibrosis: mild fibrosis (I) and moderate fibrosis (II). RESULTS: The mean expression level of microRNA-122 was significantly higher in both patient groups (I and II) as compared to the control group (III) (p < 0.001 for each). While there was no statistically significant difference in serum miR-122 expression level between group I compared to group II, microRNA 122 and 4 non invasive indexes (APRI, Forns, FIB-4, and FI) were statistically significant for prediction of fibrosis. MicroRNA 122 had the best performing ROC curve for prediction of fibrosis followed by APRI, FI, Forns, and FIB-4. The AUROCs ranged from 0.912 for FIB-4 to 1 for microRNA 122. While FIB-4 and Forns were statistically significant in differentiating mild and moderate fibrosis, FIB-4 had a better AUROC than Forns (0.75 and 0.71, respectively). CONCLUSIONS: The study concluded that there was increased expression of mcroiRNA-122 in Egyptian chronic hepatitis C virus (CHCV) infected patients. MicroRNA 122 has a strong potential to serve as one of the novel noninvasive markers of early liver fibrosis.

Role of Endogenous Bone Marrow Stem Cells Mobilization in Repair of Damaged Inner Ear in Rats.

BACKGROUND AND OBJECTIVES: The utilization of the stem cells is widely used in the last few years in different fields of medicine, either by external transplantation or endogenous mobilization, most of these studies still experimental on animals; few were tried on human as in the spinal cord injury or myocardial infarction. As regard its use in the inner ear, stem cell transplantation was examined in many previous studies, while the mobilization idea is a new method to be experimented in inner ear hair cell regeneration. The present work assessed the possibility of mobilizing endogenous bone marrow derived stem cells (SCs) in rats using granulocyte colony stimulating factor (G-CSF) to induce regeneration and repair to experimentally damaged inner ear hair cells by Amikacin injection. METHODS: The study included thirty adult Sprague Dawley male rats. Experimental induction of inner ear damage was done by repeated intratympanic injection of amikacin sulfate. Mobilization of bone marrow SCs was provoked by subcutaneous injection of GCSF. Cochlear integrity, induction of hearing loss and functional recovery of sensory hearing loss were assessed using Distortion Product Otoacoustic Emission (DPOAEs). The morphological alteration and recovery of the organ of Corti was assessed histologically using the light and scanning electron microscopes. RESULTS: After six month duration, there was improvement in 50% of the sensorineural DPOAE results. Functional recovery coincided with the repair of structural components of organ of Corti. CONCLUSIONS: SCs mobilization by G-CSF is a promising alternative method for replacement therapy in sensorineural hearing loss.

Midterm Follow-Up of Talectomy for Severe Rigid Equinovarus Feet.

Rigid equinovarus foot is a challenging problem. Talectomy has been advocated as a salvage procedure to achieve a plantigrade painless foot in the treatment of rigid equinovarus deformity. The present prospective observational study evaluated the effectiveness of talectomy in the treatment of Dimeglio grade IV rigid equinovarus feet. Nineteen feet in 13 patients were treated by talectomy from September 2001 through January 2012 (10-year, 2-month period). Of the 13 patients, 9 (69.23%) had a foot deformity due to arthrogryposis multiplex congenita and 1 (7.69%) each due to sacral agenesis, spastic cerebral palsy, neglected congenital talipes equinovarus, and post-traumatic contracture. Of the 13 patients, 9 (69.23%) were male and 4 (30.77%) were female. Their mean age was 7.7 (range 3 to 26) years. The mean follow-up duration was 6.4 (range 2 to 11) years. Along with talectomy, excision of the navicular was performed in 8 feet (42.11%), calcaneal osteotomy with a laterally based wedge in 8 (42.11%), and calcaneocuboid fusion in 3 feet (15.79%). Postoperatively, all the feet improved to Dimeglio grade II and were painless, and 16 feet (84.22%) were plantigrade; 1 foot (5.26%) had residual equinus resulting from incomplete removal of the talus and 2 (10.53%) had residual varus. Also, 3 feet (15.79%) had forefoot adduction (2 residual and 1 recurrent) that required a second surgery to correct the deformity. From our experience, talectomy is an effective procedure for correction of severe rigid equinovarus feet, provided that the talus is completely removed and the calcaneus is positioned correctly in the ankle mortise.

Combining multivariate analysis and human risk indices for assessing heavy metal contents in muscle tissues of commercially fish from Southern Red Sea, Saudi Arabia.

Jizan fishers are the major fish source for more than 1.5 million populations in the southern region in Saudi Arabia. Despite the overgrowing of various man-made activities in Jizan City, no recent study on environmental monitoring was reported. In the current study, heavy metals were quantified in muscle tissues of 12 fish species, as the most edible, from Jizan fisheries. Electrothermal atomic absorption spectrophotometry was used for quantification after microwave wet digestion. Acceptable recovery values (83.46-97.48%) for spiked fish samples with standard solutions were obtained. The following wide ranges of heavy metal concentrations (µg/g, wet weight) in studied fish species were recorded: V (0.004-0.561), Cr (0.013-0.477), Mn (0.073-0.128), As (0.002-0.935), Se (0.083-3.058), Sn (2.835-5.540), and Pb (0.150-0.386). Comparing with international permissible limits, lower levels were recorded in the current study. For total metal accumulation, the relationship between species was examined by cluster analysis, which showed that Epinephelinae was the farthest species from others. The principal component analysis shows one component indicating normal distribution of heavy metals in fish species. Different metal pollution indices (1.35-0.30), which shows the distribution of the total heavy metal concentrations in each species, were recorded. The hazard indices for muscle consumption were less than 1.0 for all studied metals at both ingestion rates except Sn which showed a marginal value of 28.9.

An in vitro spectrometric method for determining the partition coefficients of non-steroidal anti-inflammatory drugs into human erythrocyte ghost membranes.

Usefulness of second derivative spectrophotometry for determining the partition coefficients (K(p)s) of four non-steroidal anti-inflammatory drugs (NSAIDs) between human erythrocyte ghost (HEG) membranes and buffer at simulated physiological conditions (pH=7.4, 37 °C) has been adequately emphasized. In the absorption spectra for each of the investigated NSAIDs, λ(max) was red-shifted in presence of HEG membranes, indicating that NSAIDs have the nature of metachromasy between lipid bilayer and water. Further quantitative spectral data for calculating K(p)s could not be obtained from the absorption spectra because of the presence of background signal impacts of HEG lipid bilayers. Second derivative spectra were calculated from absorption spectra and fortunately showed three isosbestic derivative points for each NSAID, indicating without doubt that the background signals were entirely eliminated. From the relation between the derivative intensity change (ΔD) induced by addition of HEG membranes, K(p)s were calculated and obtained with RSD of below 6%. Fractions of partitioned NSAIDs are in well-harmony with that derived from the experimental values. Moreover, validity of the proposed method was confirmed. Conclusively, the second derivative spectrometry has proven to be a facile, reliable and more expeditious method to obtain in vitro K(p)s of drugs to HEG without previous separation.

Binding of benzodiazepine drugs to bovine serum albumin: a second derivative spectrophotometric study.

The binding constants (K values) of three benzodiazepine drugs to bovine serum albumin were determined by a second derivative spectrophotometric method. Despite the sample and reference samples were prepared in the same way to maintain the same albumin content in each sample and reference pair, the absorption spectra show that the baseline compensation was incomplete because of the strong background signals caused by bovine serum albumin. Accordingly, further quantitative spectral information could not be obtained from these absorption spectra. On the other hand, the calculated second derivative spectra clearly show isosbestic points indicating the complete removal of the residual background signal effects. Using the derivative intensity differences (ΔD values) of the studied benzodiazepine drugs before and after the addition of albumin, the binding constants were calculated and obtained with R.S.D. of less than 8%. The interactions of drugs with bovine serum albumin were investigated using Scatchard's plot. In addition, the consistency between the fractions of bound benzodiazepine calculated from the obtained K values and the experimental values were established. The results indicate that the second derivative method can be advantageously applicable to the determination of binding constants of drugs to serum albumin without prior separation. Moreover, the validity of the proposed method was confirmed.

Hypovitaminosis D in female patients with chronic low back pain.

Chronic low back pain (LBP) is an extremely common problem in practice, where it is often labeled idiopathic. No sufficient studies have been conducted to analyze the contribution of hypovitaminosis D to the etiology of chronic LBP in populations wherein vitamin D deficiency is endemic. The present study was, therefore, carried out to examine hypovitaminosis D and its determinants in female patients with chronic LBP during the childbearing period. Sixty female patients complaining of LBP lasting more than 3 months were clinically studied rheumatologically and neurologically. Questionnaires and indices quantifying risk factors associated with vitamin D deficiency were utilized. Biochemical assays of serum calcium, phosphorus, alkaline phosphatase (ALP), parathormone (PTH), and 25-hydroxyvitamin D (25 OHD) were performed and compared to those of 20 matched healthy controls. The determinants of vitamin D levels in patients were examined by stepwise regression. Patients with LBP had significantly lower 25 OHD levels (p < 0.05) and significantly higher PTH (p < 0.05) and ALP (p < 0.001) than controls, although there were no significant group differences in calcium and phosphorus. Hypovitaminosis D (25 OHD < 40 ng/ml) was found in 49/60 patients (81%) and 12/20 (60%) of controls, with an odds ratio of 2.97. Although many risk factors related to sun exposure, clothing, diet, and pregnancy were significantly correlated with vitamin D levels in patients, only limited duration of sun exposure, contributing 55% to the variance of 25 OHD, limited areas of skin exposed (13%), and increased number of pregnancies (2%), were significant determinants of vitamin D levels in patients. Despite the sunny climate, hypovitaminosis D is prevalent among Egyptian women in the childbearing period, especially those presenting with chronic LBP, where it is associated with hyperphosphatasia and hyperparathyroidism, without alterations in serum calcium. The major determinant of hypovitaminosis D in our patients is limited sun exposure.

(19)F NMR spectroscopic characterization of the interaction of niflumic acid with human serum albumin.

The interaction of a non-steroidal anti-inflammatory drug, niflumic acid (NFA), with human serum albumin (HSA) has been investigated by (19)F nuclear magnetic resonance (NMR) spectroscopy. A (19)F NMR spectrum of NFA in a buffered (pH 7.4) solution of NaCl (0.1 mol L(-1)) contained a single sharp signal of its CF(3) group 14.33 ppm from the internal reference 2,2,2-trifluoroethanol. Addition of 0.6 mmol L(-1) HSA to the NFA buffer solution caused splitting of the CF(3) signal into two broadened signals, shifted to the lower fields of 14.56 and 15.06 ppm, with an approximate intensity ratio of 1:3. Denaturation of HSA by addition of 3.0 mol L(-1) guanidine hydrochloride (GU) restored a single sharp signal of CF(3) at 14.38 ppm, indicating complete liberation of NFA from HSA as a result of its denaturation. These results suggest that the binding is reversible and occurs in at least two HSA regions. Competitive (19)F NMR experiments using warfarin, dansyl-L: -asparagine, and benzocaine (site I ligands), and L: -tryptophan and ibuprofen (site II ligands) revealed that NFA binds to site I at two different regions, Ia and Ib, in the ratio 1:3. By use of (19)F NMR with NFA as an (19)F NMR probe the nonfluorinated site I-binding drugs sulfobromophthalein and iophenoxic acid were also found to bind sites Ia and Ib, respectively. These results illustrate the usefulness and convenience of (19)F NMR for investigation of the HSA binding of both fluorinated and nonfluorinated drugs.

19F NMR spectrometric determination of the partition coefficients of some fluorinated psychotropic drugs between phosphatidylcholine bilayer vesicles and water.

A simple 19F NMR spectrometric method was proposed for the determination of the partition coefficients of fluorinated psychotropic drugs, trifluoperazine (TFPZ), flunitrazepam (FNZ) and flurazepam (FZ) between phosphatidylcholine (PC) bilayer of small unilamellar vesicles (SUVs) and water (buffer). Each 19F NMR spectrum of these drugs in the presence of PC SUV showed a single signal accompanying a PC concentration-depending shift change and broadening, which indicated a fast exchange of these drugs between the water phase and the PC bilayer of SUV. From the relationship between the 19F chemical shift change (Deltadelta) of each drug and the PC concentration, the molar partition coefficients (K(p)'s) were calculated and obtained with a good precision of RSD below 6%. The fractions of the partitioned drugs calculated by using the obtained K(p)-values were in a good agreement with the experimental values. The results demonstrate that the 19F NMR method can be usefully applied to the determination of partition coefficients of many drugs having fluorine atom(s) without any separation procedure, especially for drugs which do not have absorption in the ultraviolet or visible region, or those having absorption but show insignificant spectral changes according to their incorporation to PC bilayers (e.g. FNZ).