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1.
West Afr J Med ; 41(2): 126-134, 2024 Feb 29.
Article in English | MEDLINE | ID: mdl-38581673

ABSTRACT

BACKGROUND: Hypertension is a leading cause of morbidity and mortality globally. Over a quarter of patients with hypertension have uncontrolled hypertension. Lifestyle modification has been shown to improve blood pressure control, thus measures that would help patients with hypertension achieve positive lifestyle modification would improve BP control. The study aims to determine the effect of motivational interviews on lifestyle modification and blood pressure control among patients with hypertension attending the Family Medicine Clinics of Irrua Specialist Teaching Hospital (ISTH), Irrua, Nigeria. METHODS: The proposed study will be a randomised control trial (PACTR202301917477205). About 212 adults between 18 and 65 years with hypertension presenting to the Family Medicine Clinics of ISTH will be randomised into intervention and control groups. The intervention group will be given a motivational interview (MI) on lifestyle modification at the start of the study and monthly for 6 months in addition to standard care for the management of hypertension. The control group will be given standard care for the management of hypertension only without MI and seen monthly for 6 months. Both groups will be assessed at baseline and 6 months. At baseline, a qualitative technique will be used to determine the reason for not adopting lifestyle modification. STUDY OUTCOME: The primary outcome shall be lifestyle modification at 6 months while the secondary outcome shall be blood pressure control at 6 months. CONCLUSION: Findings from the study will provide cost-effective ways of blood pressure control and reduction in the disease burden of hypertension in Nigeria.


CONTEXTE: L'hypertension est l'une des principales causes de morbidité et de mortalité à l'échelle mondiale. Plus d'un quart des patients hypertendus ont une hypertension non contrôlée. La modification du mode de vie a été démontrée pour améliorer le contrôle de la pression artérielle, ainsi les mesures qui aideraient les patients hypertendus à réaliser une modification positive de leur mode de vie amélioreraient le contrôle de la PA. L'étude vise à déterminer l'effet des entretiens motivationnels sur la modification du mode de vie et le contrôle de la pression artérielle chez les patients hypertendus fréquentant les cliniques de médecine familiale de l'hôpital spécialisé d'enseignement d'Irrua (ISTH), Irrua, Nigeria. MÉTHODES: L'étude proposée sera un essai contrôlé randomisé (PACTR202301917477205). Environ 212 adultes âgés de 18 à 65 ans atteints d'hypertension se présentant aux cliniques de médecine familiale de l'ISTH seront randomisés en groupes d'intervention et de contrôle. Le groupe d'intervention recevra un entretien motivationnel (EM) sur la modification du mode de vie au début de l'étude et mensuellement pendant 6 mois en plus des soins standard pour la prise en charge de l'hypertension. Le groupe témoin recevra uniquement les soins standard pour la prise en charge de l'hypertension sans EM et sera vu mensuellement pendant 6 mois. Les deux groupes seront évalués au départ et à 6 mois. Au début, une technique qualitative sera utilisée pour déterminer la raison de la non-adoption de la modification du mode de vie. RÉSULTAT DE L'ÉTUDE: Le critère de jugement principal sera la modification du mode de vie à 6 mois, tandis que le critère de jugement secondaire sera le contrôle de la pression artérielle à 6 mois. CONCLUSION: Les résultats de l'étude fourniront des moyens rentables de contrôle de la pression artérielle et de réduction de la charge de morbidité de l'hypertension au Nigeria. MOTS-CLÉS: hypertension, entretien motivationnel, modification du mode de vie, contrôle de la pression artérielle, médecine familiale.


Subject(s)
Hypertension , Motivational Interviewing , Adult , Humans , Nigeria , Family Practice , Hypertension/therapy , Life Style , Blood Pressure , Hospitals, Teaching , Randomized Controlled Trials as Topic
2.
Niger. j. clin. pract. (Online) ; 18(2): 678-682, 2015.
Article in English | AIM (Africa) | ID: biblio-1267141

ABSTRACT

Background: Several international studies have shown that abuse or mistreatment is a regular phenomenon faced by medical students. However; there is limited information on medical student abuse/mistreatment in Nigeria. The study was therefore conducted to assess the prevalence and patterns of mistreatment experienced by Medical Students in the University of Calabar. Materials and Methods: A descriptive cross-sectional study was conducted among 451 undergraduate medical trainees in the University of Calabar. Systematic sampling was used in recruiting participants into the study. A self-administered questionnaire was then employed to obtain information on patterns of mistreatment experienced by medical undergraduates. Data were analyzed using Statistical Package for Social Scientists version 19 and level of significance set at 0.05. Results: More than a third (35.5) of all respondents interviewed had experienced one or more forms of mistreatment during their training; with 38.5 of them experiencing it weekly. The most common form of mistreatment experienced was verbal abuse (52.5); and the main perpetrators of these incidents were medical consultants; (18.6) other cadre of doctors (17.3) and lecturers (14.4). Being in the clinical level of study and aged above 25 years were significantly associated with experiencing mistreatment in this study (P 0.05). However; only 8.8 reported these incidents. Conclusion: With more than a third of undergraduate medical trainees experiencing mistreatment; development of appropriate strategies for the prevention and reduction of these incidents are strongly recommended


Subject(s)
Case Reports , Social Behavior , Students , Violence
3.
Niger J Clin Pract ; 17(6): 678-82, 2014.
Article in English | MEDLINE | ID: mdl-25385901

ABSTRACT

BACKGROUND: Several international studies have shown that abuse or mistreatment is a regular phenomenon faced by medical students. However, there is limited information on medical student abuse/mistreatment in Nigeria. The study was therefore conducted to assess the prevalence and patterns of mistreatment experienced by Medical Students in the University of Calabar. MATERIALS AND METHODS: A descriptive cross-sectional study was conducted among 451 undergraduate medical trainees in the University of Calabar. Systematic sampling was used in recruiting participants into the study. A self-administered questionnaire was then employed to obtain information on patterns of mistreatment experienced by medical undergraduates. Data were analyzed using Statistical Package for Social Scientists version 19 and level of significance set at <0.05. RESULTS: More than a third (35.5%) of all respondents interviewed had experienced one or more forms of mistreatment during their training, with 38.5% of them experiencing it weekly. The most common form of mistreatment experienced was verbal abuse (52.5%), and the main perpetrators of these incidents were medical consultants, (18.6%) other cadre of doctors (17.3%) and lecturers (14.4%). Being in the clinical level of study and aged above 25 years were significantly associated with experiencing mistreatment in this study (P < 0.05). However, only 8.8% reported these incidents. CONCLUSION: With more than a third of undergraduate medical trainees experiencing mistreatment, development of appropriate strategies for the prevention and reduction of these incidents are strongly recommended.


Subject(s)
Interprofessional Relations , Professional Misconduct/statistics & numerical data , Schools, Medical , Students, Medical/psychology , Adult , Cross-Sectional Studies , Female , Humans , Male , Nigeria , Prevalence , Social Behavior , Students, Medical/statistics & numerical data , Surveys and Questionnaires , Young Adult
4.
Horm Metab Res ; 34(4): 217-21, 2002 Apr.
Article in English | MEDLINE | ID: mdl-11987033

ABSTRACT

Chronic hyperglycemia is known to lead to a progressively further impaired insulin response and to hasten the development of complications in patients with type 2 diabetes, a notion referred as glucose toxicity. T-1095, a derivative of phlorizin, is a newly developed oral hypoglycemic agent that acts as a specific inhibitor of renal Na(+)-glucose co-transporters, reducing circulating blood glucose levels by promoting glucose excretion into urine. The effects of glycemic improvement by T-1095 on secretory function and cytoplasmic calcium response in pancreatic beta-cells were investigated using spontaneously diabetic GK rats. After four weeks of treatment with T-1095 (age 4 to 8 week rats), serum glucose and HbA1c levels were significantly improved (serum glucose level, GK vs. GK T-1095, 277.3 +/- 11.8 vs. 204.7 +/- 6.4 mg/dl; HbA1c level, GK vs. GK T-1095, 6.2 +/- 0.2 vs. 4.8 +/- 0.1 %). Insulin secretion induced by 16.7 mM glucose was also significantly increased in the T-1095-treated group compared to the untreated group. The [Ca(2+)]i response induced by 16.7 mM glucose in GK beta-cells was characterized by the loss of the steep first peak of [Ca(2+)]i elevation, and the lost first peak of [Ca(2+)]i reappeared in T-1095-treated beta-cells in 32 of 34 observations. In T-1095-treated beta-cells, the time lag to peak [Ca(2+)]i levels in the 16.7 mM glucose stimulation was significantly reduced (259.1 +/- 15.3 sec, p < 0.01) compared to untreated GK rats (524.7 +/- 52.9 sec). Thus, improvement of hyperglycemia by T-1095 ameliorates beta-cell function by relieving [Ca(2+)]i response.


Subject(s)
Calcium/metabolism , Carbonates/pharmacology , Diabetes Mellitus, Type 2/metabolism , Glucosides/pharmacology , Hypoglycemic Agents/pharmacology , Islets of Langerhans/drug effects , Islets of Langerhans/metabolism , Monosaccharide Transport Proteins/metabolism , Animals , Arginine/metabolism , Blood Glucose/metabolism , Calcium/antagonists & inhibitors , Diabetes Mellitus, Type 2/blood , Diabetes Mellitus, Type 2/drug therapy , Glycated Hemoglobin/metabolism , Hyperglycemia/drug therapy , Hyperglycemia/metabolism , Insulin/metabolism , Insulin Secretion , Male , Monosaccharide Transport Proteins/antagonists & inhibitors , Rats , Rats, Wistar
5.
Org Lett ; 3(21): 3309-12, 2001 Oct 18.
Article in English | MEDLINE | ID: mdl-11594821

ABSTRACT

[reaction: see text]. Phenylalanine-derived B-aryl-N-tosyloxazaborolidinones selectively activate one of two enantiotopic oxygen atoms in prochiral anti dioxane acetals derived from meso-1,3-diols, leading to enantioselective formation of ring-cleavage products. The reaction is utilized as a key step in asymmetric desymmetrization of meso-1,3-diols.

6.
Org Lett ; 3(13): 2101-3, 2001 Jun 28.
Article in English | MEDLINE | ID: mdl-11418059

ABSTRACT

[reaction: see text] O-(2-Naphthoyl)-N-tosyl-L-allo-threonine-derived B-phenyloxazaborolidinone catalyzes the asymmetric Mukaiyama-Michael addition of simple acyclic enones to give adducts of 54-85% ee. 2,6-Diisopropylphenol as an additive is demonstrated to effectively retard the undesirable Si(+)-catalyzed racemic pathway.

7.
Am J Physiol Endocrinol Metab ; 280(5): E816-24, 2001 May.
Article in English | MEDLINE | ID: mdl-11287365

ABSTRACT

To determine the molecular mechanism underlying hyperglycemia-induced insulin resistance in skeletal muscles, postreceptor insulin-signaling events were assessed in skeletal muscles of neonatally streptozotocin-treated diabetic rats. In isolated soleus muscle of the diabetic rats, insulin-stimulated 2-deoxyglucose uptake, glucose oxidation, and lactate release were all significantly decreased compared with normal rats. Similarly, insulin-induced phosphorylation and activation of Akt/protein kinase B (PKB) and GLUT-4 translocation were severely impaired. However, the upstream signal, including phosphorylation of the insulin receptor (IR) and insulin receptor substrate (IRS)-1 and -2 and activity of phosphatidylinositol (PI) 3-kinase associated with IRS-1/2, was enhanced. The amelioration of hyperglycemia by T-1095, a Na(+)-glucose transporter inhibitor, normalized the reduced insulin sensitivity in the soleus muscle and the impaired insulin-stimulated Akt/PKB phosphorylation and activity. In addition, the enhanced PI 3-kinase activation and phosphorylation of IR and IRS-1 and -2 were reduced to normal levels. These results suggest that sustained hyperglycemia impairs the insulin-signaling steps between PI 3-kinase and Akt/PKB, and that impaired Akt/PKB activity underlies hyperglycemia-induced insulin resistance in skeletal muscle.


Subject(s)
Diabetes Mellitus, Experimental/metabolism , Hyperglycemia/enzymology , Insulin/pharmacology , Muscle Proteins , Muscle, Skeletal/enzymology , Protein Serine-Threonine Kinases , Proto-Oncogene Proteins/metabolism , Animals , Biological Transport , Deoxyglucose/metabolism , Enzyme Activation/drug effects , Glucose/metabolism , Glucose Transporter Type 4 , Intracellular Membranes/physiology , Lactic Acid/metabolism , Male , Monosaccharide Transport Proteins/metabolism , Muscle, Skeletal/metabolism , Muscle, Skeletal/physiopathology , Oxidation-Reduction , Proto-Oncogene Proteins c-akt , Rats , Rats, Sprague-Dawley , Signal Transduction
8.
J Org Chem ; 66(8): 2618-23, 2001 Apr 20.
Article in English | MEDLINE | ID: mdl-11304179

ABSTRACT

Solvolysis of 4-alkoxycarbonyl-(or 4-acyl)-3-oxo-1,2,3,4-tetrahydroquinolizinium ylides (1-4) was studied and three types of reactions were found to proceed competitively. Thus, alcoholysis afforded the Chichibabin rearrangement products, 2,3-dihydro-2-indolizinones (5-8), solvolysis in trifluoroethanol or in aqueous methanol caused ring opening (and subsequent ester cleavage) to 2-alkoxycarbonylethylpyridinium-1-acetates 10, 15, and 16, and hydrolysis resulted in ring opening to 1-alkoxycarbonylmethylpyridinium-2-propionates 11 or 13 (and subsequently to 12 or 14). Characteristically, all the types of reactions proceeded significantly faster with t-butoxycarbonyl substituted ylides than with smaller alkoxycarbonyl substituted ones. The general mechanism for the solvolysis, involving a ketene intermediate, is proposed based on kinetic measurements.

9.
J Org Chem ; 66(5): 1638-46, 2001 Mar 09.
Article in English | MEDLINE | ID: mdl-11262108

ABSTRACT

By the Cu(II)-catalyzed reaction of 2-(4-diazo-3-oxoalkyl)pyridines (2), 4-alkoxycarbonyl (or 4-acyl)-3-oxo-1,2,3,4-tetrahydroquinolizinium ylides (3) were obtained in high yields. From the cycloaddition reaction of 3 with acetylenic esters (propynoates or acetylenedicarboxylates) the labile [2 + 3] cycloadducts, 3-oxo-3H-2a,4,5,8a-tetrahydropyrrolo[2,1,5-de]quinolizine-2a-carboxylates (8 or 12), were identified, which further reacted with DMAD (dimethyl acetylenedicarboxylate) to afford azocine derivatives (15 or 16) and produced pyrrolodihydroquinolizines (9 or 20) by dealkoxycarbonylation.

10.
Mol Pharmacol ; 59(2): 358-66, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11160873

ABSTRACT

OCTN2 is an Na(+)-dependent transporter for carnitine, which is essential for fatty acid metabolism, and its functional defect leads to fatal systemic carnitine deficiency (SCD). It also transports the organic cation tetraethylammonium (TEA) in an Na(+)-independent manner. Here, we studied the multifunctionality of OCTN2, by examining the transport characteristics in cells transfected with mouse OCTN2 and in juvenile visceral steatosis (jvs) mice that exhibit a SCD phenotype owing to mutation of the OCTN2 gene. The physiological significance of OCTN2 as an organic cation transporter was confirmed by using jvs mice. The embryonic fibroblasts from jvs mice exhibited significantly decreased transport of [(14)C]TEA. Pharmacokinetic analysis of [(14)C]TEA disposition demonstrated that jvs mice showed decreased tissue distribution and renal secretory clearance. In transport experiments using OCTN2-expressing cells, TEA and carnitine showed mutual trans-stimulation effects in their transport, implying a carnitine/TEA exchange mechanism. In addition, Na(+) affected the affinity of carnitine for OCTN2, whereas Na(+) is unlikely to be involved in TEA transport. This is the first molecular and physiological demonstration of the operation of an organic cation transporter in renal apical membrane. The results are consistent with the physiological coupling of carnitine reabsorption with the secretion of organic cations.


Subject(s)
Carnitine/metabolism , Carrier Proteins/physiology , Membrane Proteins/physiology , Organic Cation Transport Proteins , Tetraethylammonium/metabolism , Animals , Biological Transport , Carbon Radioisotopes , Carrier Proteins/genetics , Carrier Proteins/metabolism , Cells, Cultured , Embryo, Mammalian/cytology , Fibroblasts/metabolism , Humans , Male , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mice , Mice, Inbred C3H , Solute Carrier Family 22 Member 5 , Tetraethylammonium/blood , Tetraethylammonium/pharmacokinetics , Tissue Distribution , Tritium
11.
Br J Pharmacol ; 132(2): 578-86, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11159708

ABSTRACT

1. The therapeutic effects of an orally active inhibitor of Na(+)-glucose cotransporter (SGLT), T-1095 (a derivative of phlorizin; 3-(benzo[b]furan-5-yl)-2',6'-dihydroxy-4'-methylpropiophenone 2'-O-(6-O-methoxycarbonyl-beta-D-glycopyranoside)) were examined in C57BL/KsJ-db/db (db/db) mice, a genetic animal model of obese type 2 diabetes. 2. The higher renal SGLT activity in db/db mice than normoglycaemic C57BL/KsJ-db/+m (db/+m) mice may support the rationale for using an SGLT inhibitor in the treatment regimen for type 2 diabetes. Both T-1095 and its metabolite, T-1095A, which had approximately 10 times more potency, effectively inhibited renal SGLT activity of these mice in vitro. 3. Single oral administration of T-1095 (10, 30, 100 mg kg(-1), p.o.) to db/db mice caused a dose-dependent reduction in blood glucose levels and a concomitant increase in glucose excretion into urine. In contrast, T-1095 only slightly affected blood glucose levels in db/+m mice. 4. Chronic administration of T-1095 (0.1% w w(-1) pellet chow, for 12 weeks) decreased blood glucose and haemoglobin A(1C) levels, and improved glucose intolerance in db/db mice. The age-related decrease in plasma insulin levels was markedly inhibited and there was a 2.5 fold increase of insulin content in the pancreas of T-1095-treated db/db mice. Food consumption was not changed, while impaired body weight gain was ameliorated by T-1095 treatment. 5. Both the development of albuminuria and the expansion of glomerular mesangial area in db/db mice were significantly suppressed by chronic T-1095 treatment, indicating the prevention of the progression of diabetic nephropathy. 6. These results demonstrate that the SGLT inhibitor T-1095 is able to improve the metabolic abnormalities and inhibit the development of diabetic complications in db/db mice. Thus, T-1095 can be used for therapy of type 2 diabetic patients.


Subject(s)
Carbonates/therapeutic use , Diabetes Mellitus, Type 2/drug therapy , Glucosides/therapeutic use , Hypoglycemic Agents/therapeutic use , Membrane Glycoproteins/antagonists & inhibitors , Monosaccharide Transport Proteins/antagonists & inhibitors , Animals , Blood Glucose/metabolism , Diabetes Mellitus, Type 2/blood , Diabetes Mellitus, Type 2/genetics , Diabetic Nephropathies/pathology , Diabetic Nephropathies/prevention & control , Glucagon/metabolism , Glucose Tolerance Test , Glycosuria/metabolism , Insulin/metabolism , Kidney Glomerulus/pathology , Male , Mice , Mice, Inbred C57BL , Mice, Obese , Microvilli/drug effects , Microvilli/metabolism , Pancreas/metabolism , Phenotype , Sodium-Glucose Transporter 1
12.
J Biol Chem ; 275(51): 40064-72, 2000 Dec 22.
Article in English | MEDLINE | ID: mdl-11010964

ABSTRACT

Carnitine is essential for beta-oxidation of fatty acids, and a defect of cell membrane transport of carnitine leads to fatal systemic carnitine deficiency. We have already shown that a defect of the organic cation/carnitine transporter OCTN2 is a primary cause of systemic carnitine deficiency. In the present study, we further isolated and characterized new members of the OCTN family, OCTN1 and -3, in mice. All three members were expressed commonly in kidney, and OCTN1 and -2 were also expressed in various tissues, whereas OCTN3 was characterized by predominant expression in testis. When their cDNAs were transfected into HEK293 cells, the cells exhibited transport activity for carnitine and/or the organic cation tetraethylammonium (TEA). Carnitine transport by OCTN1 and OCTN2 was Na(+)-dependent, whereas that by OCTN3 was Na(+)-independent. TEA was transported by OCTN1 and OCTN2 but not by OCTN3. The relative uptake activity ratios of carnitine to TEA were 1.78, 11.3, and 746 for OCTN1, -2, and -3, respectively, suggesting high specificity of OCTN3 for carnitine and significantly lower carnitine transport activity of OCTN1. Thus, OCTN3 is unique in its limited tissue distribution and Na(+)-independent carnitine transport, whereas OCTN1 efficiently transported TEA with minimal expression of carnitine transport activity and may have a different role from other members of the OCTN family.


Subject(s)
Carrier Proteins/metabolism , Membrane Proteins/metabolism , Membrane Transport Proteins , Amino Acid Sequence , Animals , Base Sequence , Carrier Proteins/chemistry , Carrier Proteins/genetics , Cell Line , DNA, Complementary , Humans , Membrane Proteins/chemistry , Membrane Proteins/genetics , Mice , Molecular Sequence Data , Organic Cation Transport Proteins , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Sequence Homology, Amino Acid , Symporters
13.
Metabolism ; 49(8): 990-5, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10954015

ABSTRACT

The effect of T-1095, an inhibitor of renal glucose reabsorption, on hyperglycemia and the expression of Na+-glucose cotransporters (SGLTs) and facilitative glucose transporter 2 (GLUT2) in streptozotocin (STZ)-induced diabetic rats was examined. There was an elevation of blood glucose, hemoglobin A1c (HbA1c), kidney weight, and urinary excretion of both glucose and albumin in STZ rats. Administration of 0.03% and 0.1% (wt/wt diet) T-1095 to STZ rats for 4 weeks improved the hyperglycemia and dose-dependently decreased HbA1c. Moreover, treatment with 0.1% (wt/wt diet) T-1095 in STZ rats for 8 weeks not only reduced blood glucose and HbA1c, levels but also prevented the elevation of urinary albumin levels and kidney weight and the development of epithelial vacuolation. The expression of renal SGLT2, a major glucose transporter in the kidney, was not different in normal, STZ, and T-1095-treated STZ rats. In contrast, the elevated renal GLUT2 level in STZ rats was suppressed by T-1095. These data suggest that T-1095 improves hyperglycemia by suppressing the renal reabsorption of glucose, which results in a suppression of the development of functional and histological changes and abnormal expression of GLUT2 in the kidney.


Subject(s)
Carbonates/pharmacology , Diabetes Mellitus, Experimental/drug therapy , Glucosides/pharmacology , Hyperglycemia/drug therapy , Hypoglycemic Agents/pharmacology , Kidney/drug effects , Monosaccharide Transport Proteins/antagonists & inhibitors , Albuminuria/urine , Animals , Blood Glucose/drug effects , Blood Glucose/metabolism , Body Weight/drug effects , Diabetes Mellitus, Experimental/metabolism , Diabetes Mellitus, Experimental/urine , Glucose Transporter Type 2 , Glycated Hemoglobin/metabolism , Glycosuria/urine , Hyperglycemia/blood , Hyperglycemia/metabolism , Jejunum/cytology , Jejunum/drug effects , Jejunum/metabolism , Kidney/anatomy & histology , Kidney/metabolism , Male , Monosaccharide Transport Proteins/biosynthesis , Organ Size/drug effects , Rats , Rats, Wistar , Sodium-Glucose Transporter 2 , Urine
14.
Org Lett ; 2(13): 1855-1857, 2000 Jun 29.
Article in English | MEDLINE | ID: mdl-10891175

ABSTRACT

Treatment of terminal alkynes bearing a remote leaving group with MNR(2) (M = Li, Na, K) gives bicyclo[n.3.0]-1-alkenes (n = 3, 4). The tandem cyclization proceeds through a mechanism involving exo-cyclization of an alkynylmetal intermediate and intramolecular C-H insertion of the resulting carbenoid.

15.
J Org Chem ; 65(12): 3620-5, 2000 Jun 16.
Article in English | MEDLINE | ID: mdl-10864744

ABSTRACT

The reaction of 2-(3-diazo-2-oxopropane-1-yl)-2-methyldithiolane 9a, 2-(4-diazo-3-oxobutane-2-yl)-2-methyldithiolane 9c, and 2-(3-diazo-2-oxopropane-1-yl)-2-methyl-1,3-dithiane 9b with Rh(2)(OAc)(4) gave three-carbon ring-expansion products dithiocan-2-en-1-ones 13a, 13c and dithionan-2-en-1-one 13b, respectively. 2-(5-Diazo-4-oxopentyl)-2-methyldithiolane 9e also gave the five-carbon ring-expansion products dithionan-3-en-1-one 13e and 5-methylenedithionane-1-one 13'e. On the other hand, reaction of 2-(4-diazo-3-oxobutyl)-2-methyldithiolane 9d in the presence of AcOH gave the four-carbon ring-expansion product 16d substituted by an acetoxyl group. In addition, the reaction of 2-(3-diazo-2-oxopropyl)-2-methyl-3-oxathiolane 9f in the absence of AcOH gave 4-oxa-7-thiocan-2-en-1-one 19 via a sulfonium ylide intermediate, whereas, in the presence of AcOH, an alternative regioisomer 20 was also formed competitively with 19 via an oxonium ylide intermediate.

16.
Biochem Biophys Res Commun ; 273(1): 251-60, 2000 Jun 24.
Article in English | MEDLINE | ID: mdl-10873595

ABSTRACT

We identified three novel transporters structurally belonging to the organic anion transporting polypeptide (OATP) family in humans. Since previously known rat oatp1 to 3 do not necessarily correspond to the human OATPs in terms of either tissue distribution or function, here we designate the newly identified human OATPs as OATP-B, -D and -E, and we rename the previously known human OATP as OATP-A. OATP-C proved to be identical with the recently reported LST1/OATP-2. Expression profiles of the five OATPs and the prostaglandin transporter PGT (a member of OATP family) in human tissues showed that OATP-C is exclusively localized in liver, OATP-A and PGT are expressed in restricted ranges of tissues, and OATP-B, -D and -E show broad expression profiles. OATP-B, -C, -D and -E exhibited transport activity for [(3)H]estrone-3-sulfate as a common substrate. OATP-C has a high transport activity with broad substrate specificity.


Subject(s)
Carrier Proteins/genetics , Carrier Proteins/metabolism , Multigene Family/genetics , Amino Acid Sequence , Anion Transport Proteins , Antiporters/chemistry , Antiporters/genetics , Biological Transport , Carrier Proteins/chemistry , Carrier Proteins/classification , Cell Line , Cloning, Molecular , DNA-Binding Proteins/chemistry , DNA-Binding Proteins/genetics , Dinoprostone/metabolism , Estradiol/analogs & derivatives , Estradiol/metabolism , Estrone/analogs & derivatives , Estrone/metabolism , Gene Expression Profiling , Humans , Molecular Sequence Data , Organ Specificity , Organic Anion Transporters , Penicillin G/metabolism , Phylogeny , Physical Chromosome Mapping , Polymorphism, Single Nucleotide/genetics , RNA, Messenger/analysis , RNA, Messenger/genetics , Sequence Alignment , Substrate Specificity , Transfection
17.
J Org Chem ; 65(5): 1335-43, 2000 Mar 10.
Article in English | MEDLINE | ID: mdl-10814093

ABSTRACT

Sequential etherification of 2,2',6,6'-tetrahydroxybiphenyl (1) with 1,4-di-O-benzyl-L-threitol under Mitsunobu conditions gives desymmetrized biphenyldiol 9 of S-axial chirality exclusively. Cyclization of 9 with 1,omega-dibromoalkanes followed by removal of the chiral auxiliary yields (S)-2,2'-biphenyldiols 14 with alkylenedioxy bridges at the 6 and 6' positions. (S)-6,6'-Dialkyl- and -diphenyldiols 20 are obtained in an efficient manner via Pd(0)-catalyzed cross-coupling of bis(triflate) derivative 17 with organozinc reagents. Bis(triflate) 17 also serves as an intermediate for asymmetric synthesis of axially chiral biphenyldicarboxylic acid 23, terphenylcarboxylic acid 28, lactone 26, and lactam 30.

18.
Org Lett ; 2(9): 1319-22, 2000 May 04.
Article in English | MEDLINE | ID: mdl-10810737

ABSTRACT

[formula: see text] 2,2',6,6'-Tetrahydroxybiphenyl undergoes a facile annulation reaction with bis(mesylate) derived from (S)-1,2-propanediol in the presence of Cs2CO3 to give the corresponding asymmetric desymmetrization product of S axial chirality with exclusive diastereoselectivity. The desymmetrization product can be utilized as a versatile chiral building block in asymmetric synthesis of axially chiral 6,6'-disubstituted 2,2'-biphenyldiols.

19.
J Org Chem ; 65(7): 1899-906, 2000 Apr 07.
Article in English | MEDLINE | ID: mdl-10774007

ABSTRACT

Two types of bicyclic ortho esters 14 and 18, which are tethered to a diazocarbonyl group by polymethylene linkages--(CH2)n--of different lengths (n = 1-3 for 14 and 1-4 for 18), were prepared and catalytically decomposed by treatment with Rh2(OAc)4 either in the presence or absence of a protic nucleophile (MeOH, PhOH, AcOH) to give ring-enlargement product lactones 25 and 30 of different sizes. With 14, the enlargement took place when n = 1 or 2, but not when n = 3. With 18, in which the diazo carbon is substituted with a methoxycarbonyl group, the length of the chain can be extended further to n = 4 to obtain ring-enlargement products or their derivatives. All of these reactions could be explained in terms of the intermediacy of tricyclooxonium ylides 22 and 28. The ylides form an equilibrium with the corresponding ring-opened zwitterions 22' and 28', respectively, which, after protonation by a protic nucleophile, undergo mainly ring-enlargement to form medium-sized or large oxalactones rather than 1,2-rearrangement.

20.
Am J Physiol Endocrinol Metab ; 278(3): E535-43, 2000 Mar.
Article in English | MEDLINE | ID: mdl-10710509

ABSTRACT

To determine the contribution of hyperglycemia to the insulin resistance in various insulin-sensitive tissues of Zucker diabetic fatty (ZDF) rats, T-1095, an oral sodium-dependent glucose transporter (SGLT) inhibitor, was administered by being mixed into food. Long-term treatment with T-1095 lowered both fed and fasting blood glucose levels to near normal ranges. A hyperinsulinemic euglycemic clamp study that was performed after 4 wk of T-1095 treatment demonstrated partial recovery of the reduced glucose infusion rate (GIR) in the T-1095-treated group. In the livers of T-1095-treated ZDF rats, hepatic glucose production rate (HGP) and glucose utilization rate (GUR) showed marked recovery, with almost complete normalization of reduced glucokinase/glucose-6-phosphatase (G-6-Pase) activities ratio. In adipose tissues, decreased GUR was also shown to be significantly improved with a normalization of insulin-induced GLUT-4 translocation. In contrast, in skeletal muscles, the reduced GUR was not significantly improved in response to amelioration of hyperglycemia by T-1095 treatment. These results suggest that the contribution of hyperglycemia to insulin resistance in ZDF rats is very high in the liver and considerably elevated in adipose tissues, although it is very low in skeletal muscle.


Subject(s)
Adipose Tissue/physiopathology , Diabetes Mellitus/physiopathology , Hyperglycemia/physiopathology , Insulin Resistance , Liver/physiopathology , Muscle Proteins , Muscle, Skeletal/physiopathology , Obesity , Adipocytes/metabolism , Animals , Blood Glucose/analysis , Carbonates/pharmacology , Diabetes Mellitus/blood , Glucokinase/metabolism , Glucose Transporter Type 4 , Glucose-6-Phosphatase/metabolism , Glucosides/pharmacology , Hyperinsulinism/physiopathology , Liver/enzymology , Monosaccharide Transport Proteins/metabolism , Rats , Rats, Zucker
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