Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 114
Filtrar
3.
Clin Case Rep ; 12(3): e8640, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38444926

RESUMO

We are reporting a case of hypothyroidism presenting as fissured tongue, demonstrating significant resolution of fissure tongue upon thyroid hormone replacement therapy.

4.
Nano Lett ; 23(24): 11533-11539, 2023 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-38100087

RESUMO

The established paradigm to create valley states, excitations at local band extrema ("valleys"), is through selective occupation of specific valleys via circularly polarized laser pulses. Here we show a second way exists to create valley states, not by valley population imbalance but by "light-shaping" in momentum space, i.e. controlling the shape of the distribution of excited charge at each valley. While noncontrasting in valley charge, such valley states are instead characterized by a valley current, identically zero at one valley and finite and large at the other. We demonstrate that these (i) are robust to quantum decoherence, (ii) allow lossless toggling of the valley state with successive femtosecond laser pulses, and (iii) permit valley contrasting excitation both with and without a gap. Our findings open a route to robust ultrafast and switchable valleytronics in a wide scope of 2d materials, bringing closer the promise of valley-based electronics.

5.
Nano Lett ; 23(22): 10305-10310, 2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-37956341

RESUMO

The field of valleytronics considers the creation and manipulation of "valley states", charge excitations characterized by a particular value of the crystal momentum in the Brillouin zone. Here we show, using the example of minimally gapped (≤40 meV) graphene, that there exist lightforms that create almost perfect valley contrasting current states (up to ∼80% valley purity) in the absence of a valley contrasting charge excitation. These "momentum streaked" THz waveforms act by deforming the excited state population in momentum space such that current flows at one valley yet is blocked at the conjugate valley. This approach both unlocks the potential of graphene as a materials platform for valleytronics, as gaps of 10-40 meV are robustly found in useful experimental contexts such as graphene/hBN systems, while simultaneously providing a tool toward ultrafast light control of valley currents in diverse minimally gapped matter, including many topological insulator systems.

6.
J Nat Prod ; 86(11): 2502-2513, 2023 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-37939299

RESUMO

2-Alkylquinolones are a class of microbial natural products primarily produced in the Pseudomonas and Burkholderia genera that play a key role in modulating quorum sensing. Bacterial alkylquinolones were synthesized and then subjected to oxidative biotransformation using human cytochrome P450 enzyme CYP4F11, heterologously expressed in the fission yeast Schizosaccharomyces pombe. This yielded a range of hydroxylated and carboxylic acid derivatives which had undergone ω-oxidation of the 2-alkyl chain, the structures of which were determined by analysis of NMR and MS data. Oxidation efficiency depended on chain length, with a chain length of eight or nine carbon atoms proving optimal for high yields. Homology modeling suggested that Glu233 was relevant for binding, due to the formation of a hydrogen bond from the quinolone nitrogen to Glu233, and in this position only the longer alkyl chains could come close enough to the heme moiety for effective oxidation. In addition to the direct oxidation products, a number of esters were also isolated, which was attributed to the action of endogenous yeast enzymes on the newly formed ω-hydroxy-alkylquinolones. ω-Oxidation of the alkyl chain significantly reduced the antimicrobial and antibiofilm activity of the quinolones.


Assuntos
Bactérias , Sistema Enzimático do Citocromo P-450 , Humanos , Oxirredução , Sistema Enzimático do Citocromo P-450/metabolismo , Família 4 do Citocromo P450/metabolismo
7.
Curr Microbiol ; 80(11): 361, 2023 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-37796343

RESUMO

Extra-pulmonary tuberculosis (EPTB) continues to be difficult to diagnose. Novel biomarkers in biological specimens offer promise. Detection of Mycobacterium tuberculosis (Mtb) DNA in urine could prove useful in diagnosis of EPTB, possibly due to disseminated disease or micro-abscesses reported in kidneys. The current study was designed to detect Mtb DNA in stored urine samples from patients with EPTB. Diagnosis of EPTB was reached using Microbiological Reference Standards (MRS) on samples from the disease site using WHO Recommended Diagnostics (WRD), [smear microscopy, liquid culture (MGIT-960)] and GX (molecular WRD, mWRD) and Comprehensive reference standards [CRS, clinical presentation, microbiological reference standards, radiology, histopathology]. GX-Ultra was performed on urine samples stored in -80oC deep freezer, retrospectively. Of 70 patients, 51 (72.9%) were classified as confirmed TB, 11 (15.7%) unconfirmed TB, and 8 (11.4%) unlikely TB. GX-Ultra in urine samples demonstrated sensitivity of 52.9% and specificity of 57.9% against MRS, and higher sensitivity of 56.5% and specificity of 100% against CRS. The sensitivity and specificity of GX-Ultra in urine was 53.6% and 75% for pus sample subset and 52.2% and 53.3% for fluid sample subset. Urine being non-invasive and easy to collect, detection of Mtb DNA using mWRD in urine samples is promising for diagnosis of EPTB.


Assuntos
Tuberculose Extrapulmonar , Humanos , Estudos Retrospectivos , Rim , Microscopia , DNA
8.
Curr Issues Mol Biol ; 45(9): 7130-7146, 2023 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-37754235

RESUMO

Cytochromes P450 (CYP) and UDP-glucuronosyltransferases (UGT) are two enzyme families that play an important role in drug metabolism, catalyzing either the functionalization or glucuronidation of xenobiotics. However, their mutual interactions are poorly understood. In this study, the functional interactions of human CYP2D6 with four human UGTs (UGT1A7, UGT1A8, UGT1A9, and UGT2A1) were investigated using our previously established co-expression model system in the fission yeast Schizosaccharomyces pombe. The substrate employed was propranolol because it is well metabolized by CYP2D6. Moreover, the CYP2D6 metabolite 4-hydroxypropranolol is a known substrate for the four UGTs included in this study. Co-expression of either UGT1A7, UGT1A8, or UGT1A9 was found to increase the activity of CYP2D6 by a factor of 3.3, 2.1 or 2.8, respectively, for the conversion of propranolol to 4-hydroxypropranolol. In contrast, UGT2A1 co-expression did not change CYP2D6 activity. On the other hand, the activities of all four UGTs were completely suppressed by co-expression of CYP2D6. This data corroborates our previous report that CYP2D6 is involved in functional CYP-UGT interactions and suggest that such interactions can contribute to both adverse drug reactions and changes in drug efficacy.

9.
10.
Cureus ; 15(5): e39712, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37398753

RESUMO

BACKGROUND: Antiseizure drug valproate alters thyroid functions. Magnesium is implicated in the pathogenesis of epilepsy and it may affect the efficacy of valproate and thyroid functions. OBJECTIVE: To study the effect of six months of valproate monotherapy on thyroid functions and serum magnesium levels. To study the association among these levels and the effects of clinicodemographic profile. MATERIALS AND METHOD: Children aged three to 12 years presenting with newly diagnosed epilepsy were enrolled. A venous blood sample was collected for estimation of thyroid function test (TFT), magnesium, and valproate levels at onset and after six months of valproate monotherapy. Valproate levels and TFT were analyzed by chemiluminescence and magnesium by colorimetric method. RESULTS: Thyroid stimulating hormone (TSH) increased significantly from 2.14±1.64 µIU/ml at enrollment to 3.64±2.15 µIU/ml at six months (p<0.001), free thyroxine (FT4) decreased significantly (p<0.001). Serum magnesium (Mg) decreased from 2.30±0.29 mg/dl to 1.94±0.28 mg/dl (p<0.001). At six months, eight out of 45 (17.77%) participants had significantly increased mean TSH levels (p=0.008). Serum valproate levels were not associated significantly with TFT and Mg (p<0.05). There was no effect of age, sex, or repeat seizures on the measured parameters. CONCLUSION: The TFT and Mg levels are altered by six months of valproate monotherapy in children with epilepsy. Hence we suggest monitoring and supplementation if required.

12.
Indian Pediatr ; 60(11): 913-916, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37260065

RESUMO

OBJECTIVE: To evaluate the efficacy and safety of sublingual methylcobalamin for the treatment of vitamin B12 deficiency anemia in children. METHODS: A single arm intervention study was conducted between November, 2020 and April, 2022 in children aged 1-12 years with vitamin B12 deficiency anemia. Children aged 1-6 years received a tablet of methylcobalamin (1500 mcg) by sublingual route every alternate day (three doses) while those aged 7-12 years received five such doses. Thereafter, one such sublingual tablet was given weekly and all participants were followed-up for 6 weeks. RESULTS: 37 children with a mean (SD) age of 8.2 (4.1) years were treated and followed up prospectively. On day 10, no child needed rescue therapy with parenteral methylcobalamin. After 6 weeks, the mean (SD) serum cobalamin (mL) increased from 123.3 (35.5) pg/mL to 507.3 (274.2) pg/mL (P<0.001), plasma homocysteine (L) decreased from 48.9 (17.8) pg/mL to 16.3 (8.5) µmol/L (P<0.001), the mean (SD) hemoglobin increased by 2.3 (1.1) g/dL (P<0.001), and MCV decreased by 12.9 (6.8) fL (P<0.001). 67.6% children persisted to have anemia, albeit majority of them had mild or moderate anemia. There were no unsolicited side-effect reported. CONCLUSION: Sublingual methylcobalamin is effective for the treatment of vitamin B12 deficiency anemia in children; although, the duration of treatment needs to be longer than six weeks.


Assuntos
Anemia , Gastroenteropatias , Deficiência de Vitamina B 12 , Humanos , Criança , Deficiência de Vitamina B 12/tratamento farmacológico , Vitamina B 12/uso terapêutico , Comprimidos/uso terapêutico
13.
Sci Rep ; 13(1): 6976, 2023 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-37117209

RESUMO

Rapid, cost-effective, and sensitive diagnostic assays are essential for global tuberculosis (TB) control, especially in high TB burden, resource-limited settings. The current study was designed to evaluate diagnostic accuracy of Truenat MTB-Rif Dx (MolBio) in children less than 18 years of age, with symptoms suggestive of TB. Gastric aspirate, induced sputum, and broncho-alveolar lavage samples were subjected simultaneously to AFB-smear, GeneXpert MTB/RIF, liquid culture (MGIT-960) and Truenat MTB-Rif Dx. The index-test results were evaluated against microbiological reference standards (MRS). Truenat MTB-Rif Dx had a sensitivity of 57.1%, specificity of 92% against MRS. The sensitivity and specificity of the Truenat MTB-RIF Dx compared with liquid culture was 58.7% and 87.5% while GeneXpert MTB/RIF was 56% and 91.4%. The performance of both GeneXpert MTB/RIF and Truenat MTB-Rif Dx are comparable. Result of our study demonstrates that Truenat MTB-Rif can aid in early and efficient diagnosis of TB in children.


Assuntos
Mycobacterium tuberculosis , Tuberculose Pulmonar , Tuberculose , Humanos , Criança , Tuberculose Pulmonar/diagnóstico , Tuberculose Pulmonar/microbiologia , Mycobacterium tuberculosis/genética , Tuberculose/diagnóstico , Escarro/microbiologia , Sensibilidade e Especificidade
14.
Sci Adv ; 9(11): eadf3673, 2023 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-36921048

RESUMO

Spin and valley indices represent the key quantum labels of quasi-particles in a wide class of two-dimensional materials and form the foundational elements of the fields of spintronics and valleytronics. Control over these degrees of freedom, therefore, remains the central challenge in these fields. Here, we show that femtosecond laser light combining optical frequency circularly polarized pulse and a terahertz (THz) frequency linearly polarized pulse, a so-called "hencomb" pulse, can generate precisely tailored and 90% pure spin currents for the dichalcogenide WSe2 and >75% pure valley currents for bilayer graphene with gaps greater than 120 millielectron volts (dephasing time, 20 femtoseconds). The frequency of the circular light component and the polarization vector of the THz light component are shown to represent the key control parameters of these pulses. Our results thus open a route toward light control over spin/valley current states at ultrafast times.

16.
Biomedicines ; 11(2)2023 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-36830817

RESUMO

Cytochromes P450 (CYPs) and UDP-glucuronosyltransferases (UGTs) are the most important human drug metabolizing enzymes, but their mutual interactions are poorly understood. In this study, we recombinantly co-expressed of each one of the 19 human members of the UGT families 1 and 2 with either CYP2C9, CYP2D6, or CYP4Z1 in fission yeast. Using these strains, we monitored a total of 72 interactions: 57 cases where we tested the influence of UGT co-expression on CYP activity and 15 cases of the opposite approach. In the majority of cases (88%), UGT co-expression had a statistically significant (p < 0.05) effect on P450 activity (58% positive and 30% negative). Strong changes were observed in nine cases, including one case with an activity increase by a factor of 23 (CYP2C9 activity in the presence of UGT2A3) but also four cases with a complete loss of activity. When monitoring the effect of CYP co-expression on the activity of five UGTs, activity changes were generally not so pronounced and, if observed, always detrimental. UGT2B7 activity was not influenced by CYP co-expression, while the other UGTs were affected to varying degrees. These data suggest the notion that mutual influence of CYPs and UGTs on each other's activity is a widespread phenomenon.

17.
Appl Biochem Biotechnol ; 195(2): 1042-1058, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36287330

RESUMO

We report the synthesis of 21 new proluciferin compounds that bear a small aliphatic ether group connected to the 6' hydroxy function of firefly luciferin and either contain an acid or methyl ester function at the dihydrothiazole ring. Each of these compounds was found to be a substrate for some members of the human CYP1 and CYP3 families; a total of 92 new enzyme-substrate pairs were identified. In a screen of the whole human P450 complement (CYPome) with three selected proluciferin acid substrates, another 13 enzyme-substrate pairs were detected, which involve enzymes belonging to the CYP2, CYP4, CYP7, CYP21, and CYP27 families. All in all, we identified new probe substrates for members of seven out of 18 human CYP families.


Assuntos
Sistema Enzimático do Citocromo P-450 , Humanos
18.
Mini Rev Med Chem ; 23(6): 700-718, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35986542

RESUMO

Tuberculosis (TB) is an airborne infection caused by the bacteria Mycobacterium Tuberculosis (MTB). It mainly affects the lungs and causes severe coughing, fever, and chest pains. With the rising prevalence of drug-resistant and inactive Tuberculosis (TB), there is an essential need to discover more effective molecules capable of combating this heinous illness. Pyrazinamide is a first-line tuberculosis therapy that shortens prophylactic duration from twelve to six months. The majority of presently used tuberculosis medications were found by a mix of serendipity and innovative chemical alterations of an existing lead drug. Given that the majority of these discoveries occurred years ago, there is a definite need to use fresh methodologies and technology for discovery to meet the grave danger posed by tuberculosis and the rise of treatment resistance strains. Although current research has provided significant insight into TB transmission, diagnosis, and treatment in the last four years, much more progress is needed to successfully reduce tuberculosis prevalence and eventually eradicate it. The disease continues to be a public health concern, second only to HIV/AIDS in high fatality rates. This review focuses on current efforts to translate the anti-tubercular activity of all known pyrazinamide analogues and proposes a novel approach for developing new anti-tubercular drugs based on the fusion of pyrazinamide with various heterocyclic rings that shorten treatment for drug-sensitive and multidrug-resistant tuberculosis.


Assuntos
Mycobacterium tuberculosis , Tuberculose Resistente a Múltiplos Medicamentos , Tuberculose , Humanos , Pirazinamida/farmacologia , Pirazinamida/uso terapêutico , Pirazinamida/química , Antituberculosos/farmacologia , Antituberculosos/uso terapêutico , Antituberculosos/química , Tuberculose/tratamento farmacológico , Tuberculose/microbiologia , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Relação Estrutura-Atividade
19.
Bioorg Chem ; 131: 106330, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36565673

RESUMO

Cytochrome P450 enzymes (CYPs) are one of the most important classes of oxidative enzymes in the human body, carrying out metabolism of various exogenous and endogenous substrates. In order to expand the knowledge of these enzymes' specificity and to obtain new natural product derivatives, CYP4F11, a cytochrome P450 monooxygenase, was used in the biotransformation of dialkylresorcinols 1 and 2, a pair of antibiotic microbial natural products. This investigation resulted in four biotransformation products including two oxidative products: a hydroxylated derivative (3) and a carboxylic acid derivative (4). In addition, acetylated (5) and esterified products (6) were isolated, formed by further metabolism by endogenous yeast enzymes. Oxidative transformations were highly regioselective, and took place exclusively at the ω-position of the C-5 alkyl chain. Homology modeling studies revealed that optimal hydrogen bonding between 2 and the enzyme can only be established with the C-5 alkyl chain pointing towards the heme. The closely-related CYP4F12 was not capable of oxidizing the dialkylresorcinol 2. Modeling experiments rationalize these differences by the different shapes of the binding pockets with respect to the non-oxidized alkyl chain. Antimicrobial testing indicated that the presence of polar groups on the side-chains reduces the antibiotic activity of the dialkylresorcinols.


Assuntos
Antibacterianos , Sistema Enzimático do Citocromo P-450 , Resorcinóis , Humanos , Antibacterianos/metabolismo , Biotransformação , Sistema Enzimático do Citocromo P-450/metabolismo , Oxirredução , Resorcinóis/metabolismo
20.
Am J Reprod Immunol ; 89(2): e13632, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36494901

RESUMO

BACKGROUND: Female genital tuberculosis (FGTB), an important clinical sub-type of extra-pulmonary tuberculosis (EPTB) is responsible for about 10% cases of infertility in India. Both FGTB and latent genital tuberculosis (LGTB) can cause infertility through blockage of fallopian tubes and through altered uterine endometrial receptivity. AIMS: This review tries to elucidates the role of various immune factors in FGTB and LGTB. CONTENT: Various immune disturbances are observed in FGTB and LGTB like growth factors and cytokines which inhibit implantation and several inflammatory signaling pathways like mitogen activated protein kinase (MAPK), natural killer (NK) cells, nuclear factor kappa-B (NF-KB), tumor necrosis factor (TNF), and toll like receptors (TLR) signaling are dysregulated. These altered immune factors and pathways may be detected in the endometrial biopsies at the early stages of disease before permanent damage. Prompt and adequate treatment with the four anti-tubercular drugs (rifampicin [R], isoniazid [H], pyrazinamide [Z], and ethambutol [E]) can increase pregnancy rates in some of these women. Assisted reproduction especially in-vitro fertilization and embryo transfer may be required for some women. IMPLICATIONS: Inflammatory pathways identified from the gene profiling have enabled development of potential biomarkers for early diagnosis of FGTB. Immunomodulation and novel biotechniques like stem cell transplantation, nanoparticles and host directed therapies are being tried in selected patients of FGTB and LGTB with promising results.


Assuntos
Infertilidade Feminina , Tuberculose dos Genitais Femininos , Gravidez , Feminino , Humanos , Tuberculose dos Genitais Femininos/diagnóstico , Tuberculose dos Genitais Femininos/tratamento farmacológico , Tuberculose dos Genitais Femininos/patologia , Infertilidade Feminina/tratamento farmacológico , Etambutol/uso terapêutico , Fertilização In Vitro , Tubas Uterinas/patologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...