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1.
Case Rep Urol ; 2021: 9981381, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34603815

RESUMEN

INTRODUCTION: The genitourinary system is a recognized site for multiple primary malignant neoplasms even without syndromic anomalies. However, to the best of our knowledge, a case of upper tract urothelial carcinoma (UTUC) with contralateral renal cell carcinoma (RCC) is not reported in surgical literature so far. Case Presentation. A 52-year-old Sri Lankan male patient was found to have a right lower ureteric tumour and a left renal mass together upon investigating for painless visible hematuria. The right ureteric tumour measured 32 × 22 mm resulting in moderate hydronephrosis and cortical thinning of the right kidney, and the left renal mass measured 43 × 38 mm involving the lower pole. The biopsy of the right ureteric lesion revealed a high-grade transitional cell carcinoma with focal nested pattern and that of the left renal mass revealed a clear cell carcinoma. Right nephroureterectomy followed by a left partial nephrectomy was performed in six weeks' interval. The histology of both the resected specimens confirmed the biopsy findings. Discussion. A high-risk upper tract urothelial carcinoma such as the right ureteric tumour of this patient required a nephroureterectomy which makes the management of the contralateral renal cell carcinoma more complex. An adequate functional renal remnant was ensured after offering oncologically sound surgical treatment for both the malignancies of this patient. CONCLUSION: A UTUC when associated with a contralateral RCC poses challenges in patient management. The preservation of renal excretory function has to be considered as an important determinant in addition to oncologically sound surgical resection when managing complex cases of genitourinary malignancies involving both sides of the upper urinary tract.

2.
Animal ; 13(7): 1376-1384, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30501685

RESUMEN

Protein is the most costly nutrient in fish feed, and while diets offered in the early stages of development typically have high levels of CP, they do not always correspond to the real requirements of the animals. Thus, research that seeks to learn the true nutritional requirements of fish is fundamental to improving commercial fish culture. The present study evaluated the protein requirements of Nile tilapia (Oreochromis niloticus) under larviculture. Fish performance, gene expression for digestive enzymes and their enzymatic activity and stress response to air exposure were analyzed. Four experimental diets differing in CP level were formulated: 30%, 36%, 42% and 48%. Fish larvae were fed the experimental diets during development and sampled 10, 20 and 30 days after the beginning of the experiment for performance, gene expression and enzymatic activity. At sampling time 30, stress resistance was also evaluated by means of an air exposure test. At sampling time 10, CP levels between 36% and 48% could be used for a better performance. During this period, pepsinogen expression was greater for 30% CP, intermediate for 42% and lower for 36% and 48%. After this initial period, diets of between 30% and 42% CP are recommended for better performance. At sampling time 20, gene expression for digestive enzymes and their enzymatic activity were similar for all diets tested. At sampling time 30, the diet of 42% CP induced both greater pepsinogen expression and pepsin activity. Survival after the air exposure test after 30 days of feeding was influenced by CP level in the diet, with the highest survival being for fish fed with 36% CP. Taken together, the present results demonstrate that dietary CP influences digestive enzyme gene expression and activity, and suggest that the best CP levels for Nile tilapia larviculture vary depending on larval stage.


Asunto(s)
Alimentación Animal/análisis , Cíclidos/crecimiento & desarrollo , Dieta/veterinaria , Proteínas en la Dieta/administración & dosificación , Alimentación Animal/normas , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Cíclidos/genética , Cíclidos/metabolismo , Dieta/normas , Regulación Enzimológica de la Expresión Génica , Larva/enzimología , Larva/genética , Larva/crecimiento & desarrollo
3.
J Transcat Intervent ; 26(supl. 1): 34-35, jun., 2018.
Artículo en Portugués | Sec. Est. Saúde SP, SESSP-IDPCPROD, Sec. Est. Saúde SP | ID: biblio-1046784

RESUMEN

INTRODUÇÃO: Os dados de resultados a longo prazo após valvoplastia mitral percutânea (VMP) em pacientes portadores de estenose mitral ainda são escassos e os sistemas de pontuação atuais têm limitações. Propomos um novo escore capaz de predizer sucesso imediato e tardio em pacientes elegíveis para o tratamento de estenose mitral por VMP, baseando-se nas análises de características ecocardiográficas, fatores clínicos e hemodinâmicos relevantes. MÉTODOS: Análise retrospectiva de 1582 pacientes com estenose mitral grave que foram submetidos à VMP no período de agosto de 1987 a junho de 2011 em um único centro. O período de seguimento dos pacientes apresentou mediana de 8,3 anos, com um seguimento máximo de até 23 anos. O desfecho combinado foi composto de morte cardiovascular, nova VMP ou cirurgia para plastia/troca valvar mitral. Dois modelos estatísticos foram construídos para prever a sobrevivência imediata e de longo prazo livre de eventos. RESULTADOS: A média de idade dos pacientes foi de 36,8±12,9 anos e houve prevalência do sexo feminino (86,4%). A maioria dos pacientes no momento da VMP apresentavam classe funcional New York Heart Associaton (NYHA) III (57,7%) e escore de Wilkins entre 9-11 (49,1%). Na análise multivariada para predição de sucesso imediato tiveram significância estatística a idade, tamanho de átrio esquerdo, gradiente transvalvar mitral médio e pontuação pelo escore de Wilkins. Para predição de sucesso tardio tiveram significância estatística idade, classe funcional, tamanho de átrio esquerdo e pontuação pelo escore de Wilkins. CONCLUSÃO: Na ampla população estudada tornou-se evidente que não somente o escore de Wilkins parece ter relevância na predição de sucesso imediato e tardio para os pacientes com estenose mitral reumática submetidos a VMP. Além de parâmetros ecocardiográficos, os parâmetros clínicos e hemodinâmicos também parecem contribuir de forma importante no sucesso imediato do procedimento, bem como no tempo livre de intervenções e mortalidade a longo prazo. (AU)


Asunto(s)
Humanos , Valvuloplastia con Balón , Estenosis de la Válvula Mitral , Puntaje de Propensión
4.
J Med Case Rep ; 11(1): 293, 2017 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-29058619

RESUMEN

BACKGROUND: A wide variety of complications due to the extrauterine migration of intrauterine contraceptive devices have been reported in the literature. Here we describe the case of a large bladder stone formed around a migrated Copper T380A device that was neglected and detected 15 years after insertion. CASE PRESENTATION: A 48-year-old Sri Lankan woman underwent a workup for lower urinary tract symptoms and recurrent urinary tract infections over the previous 6 months. The radiographs showed a large bladder stone with an imprint of an intrauterine contraceptive device in the center of it. The device had been inserted 15 years previously. Two years after the insertion, it was considered to be missing, but our patient did not comply with the recommended follow-up. She had been completely asymptomatic until she developed lower urinary tract symptoms. After confirming the location of the stone via ultrasonography, a vesicolithotomy was performed, revealing a stone with three limbs corresponding to the shape of the Copper T380A device. The device and the threads were fully covered with the stone material. Our patient was asymptomatic following the surgery. CONCLUSIONS: A migrated intrauterine contraceptive device can act as the nidus for the formation of a secondary bladder stone. The detailed imprint of the device inside the stone and the laminated appearance of the stone material were characteristic of a secondary bladder stone formed around an intrauterine contraceptive device. Radiography and ultrasonography are adequate for the diagnosis of intravesical migration of intrauterine contraceptive devices.


Asunto(s)
Migración de Cuerpo Extraño/complicaciones , Dispositivos Intrauterinos/efectos adversos , Cálculos de la Vejiga Urinaria/etiología , Cálculos de la Vejiga Urinaria/cirugía , Femenino , Humanos , Persona de Mediana Edad , Vejiga Urinaria/cirugía
5.
J Med Case Rep ; 11(1): 123, 2017 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-28468689

RESUMEN

BACKGROUND: Splenic artery aneurysm is rare and its diagnosis is challenging due to the nonspecific nature of the clinical presentation. We report a case of a splenic artery aneurysm in which the patient presented with chronic dyspepsia and multiple episodes of minor intragastric bleeding. CASE PRESENTATION: A 60-year-old, previously healthy Sri Lankan man presented with four episodes of hematemesis and severe dyspeptic symptoms over a period of 6 months. The results of two initial upper gastrointestinal endoscopies and an abdominal ultrasound scan were unremarkable. A third upper gastrointestinal endoscopy detected a pulsatile bulge at the posterior wall of the gastric antrum. A contrast-enhanced computed tomogram of his abdomen detected a splenic artery aneurysm measuring 3 × 3 × 2.5 cm. While awaiting routine surgery, he developed a torrential upper gastrointestinal bleeding and shock, leading to emergency laparotomy. Splenectomy and en bloc resection of the aneurysm with the posterior stomach wall were performed. Histology revealed evidence for a true aneurysm without overt, acute, or chronic inflammation of the surrounding gastric mucosa. He became completely asymptomatic 2 weeks after the surgery. CONCLUSIONS: Splenic artery aneurysms can result in recurrent upper gastrointestinal bleeding. The possibility of impending catastrophic bleeding should be remembered when managing patients with splenic artery aneurysms after a minor bleeding. Negative endoscopy and ultrasonography should require contrast-enhanced computed tomography to look for the cause of recurrent upper gastrointestinal bleeding.


Asunto(s)
Aneurisma Roto/complicaciones , Hemorragia Gastrointestinal/etiología , Arteria Esplénica , Abdomen/diagnóstico por imagen , Aneurisma Roto/diagnóstico por imagen , Aneurisma Roto/cirugía , Endoscopía Gastrointestinal , Humanos , Masculino , Persona de Mediana Edad , Esplenectomía , Arteria Esplénica/diagnóstico por imagen , Arteria Esplénica/patología , Estómago/cirugía , Tomografía Computarizada por Rayos X , Resultado del Tratamiento , Ultrasonografía
6.
J Med Case Rep ; 11(1): 84, 2017 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-28347353

RESUMEN

BACKGROUND: Only a limited number of multiple synchronous primary malignancies of the pancreas have been reported in the medical literature. We report a case of two solid malignant tumors of the pancreas diagnosed preoperatively. CASE PRESENTATION: We describe a 65-year-old Sri Lankan woman who presented with progressive obstructive jaundice. Initial contrast-enhanced computed tomography imaging detected a malignant tumor at the tail of her pancreas. A second tumor of the pancreatic head was detected with integrated imaging using multidetector computed tomography and multimodal magnetic resonance imaging. She underwent total pancreaticoduodenectomy and splenectomy. Gross examination of the specimen confirmed the presence of two separate tumors. Histology of the ampullary tumor showed pancreatic-type adenocarcinoma and the tumor in the tail of her pancreas showed a colloid-type adenocarcinoma. CONCLUSION: The possibility of multiple primary malignant solid tumors of different types with malignant potential has to be considered even without background pathology when managing multiple tumors in the pancreas.


Asunto(s)
Ictericia Obstructiva/diagnóstico por imagen , Neoplasias Primarias Múltiples/diagnóstico por imagen , Páncreas/patología , Neoplasias Pancreáticas/patología , Pancreaticoduodenectomía , Esplenectomía , Anciano , Femenino , Humanos , Ictericia Obstructiva/etiología , Ictericia Obstructiva/patología , Imagen Multimodal , Neoplasias Primarias Múltiples/patología , Neoplasias Pancreáticas/clasificación , Neoplasias Pancreáticas/diagnóstico por imagen , Resultado del Tratamiento
7.
Reprod Domest Anim ; 52(1): 144-152, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27868249

RESUMEN

The objective of this study was to evaluate the effects of vitamin C on growth and quality of semen from Oreochromis niloticus breeders. One hundred and sixty males were fed with different levels of vitamin C (0, 261, 599 and 942 mg/kg diet). The higher weight values were recorded for 599 (166 g) and 942 (175 g) mg of vitamin C/kg diet. Sperm motility, vigour and concentration were higher with 599 and 942 mg of vitamin C/kg diet. The semen volume, gonadosomatic index and plasma protein data from the last week showed a direct relationship with increasing levels of vitamin C. No changes were observed in the hepatosomatic index and blood glucose. The haematocrit and erythrocyte showed higher values estimated by equations derived at 850 and 638 mg vitamin C/kg diet, respectively. The leucocytes were inversely proportional to the increasing levels of vitamin C. After 100 days of feeding, animals fed the diet containing 942 mg vitamin C/kg diet had higher sperm motility, linearity, curvilinear velocity, straight line velocity and average path velocity (p < .05). Higher values of beat cross-frequency were observed in broodfish fed diets containing 942 and 599 mg vitamin C/kg. The different vitamin C levels did not cause differences in straightness, lateral head displacement and sperm morphology. For Nile tilapia males on intensive rearing and handling conditions, vitamin C levels between 599 and 942 mg/kg may be used for a better performance and quality of semen.


Asunto(s)
Ácido Ascórbico/administración & dosificación , Cíclidos/crecimiento & desarrollo , Dieta/veterinaria , Suplementos Dietéticos , Semen/fisiología , Animales , Masculino , Motilidad Espermática
8.
J Fish Biol ; 90(3): 922-935, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27981570

RESUMEN

The growth, physiology and skin pigmentation of pacamã Lophiosilurus alexandri juveniles were evaluated in an experiment using different tank colours (white, yellow, green, blue, brown and black) over an 80 day period. The tank colours did not cause significant differences to final body mass, total length, survival rate, carcass composition (moisture, crude protein, ash, ether extract, calcium, phosphorus, energy), or to plasma protein, triglyceride and cholesterol values. Haematocrit values, however, were highest for fish kept in white tanks (ANOVA P < 0·05), while the greatest haemoglobin levels were recorded for fish kept in blue and brown tanks (P < 0·01). The concentrations of cortisol (P < 0·001) and glucose (P < 0·01) were the most in fish in the black tanks. Tank colour affected skin pigmentation significantly, with fish in white tanks having the highest values of L* (brightness) and the lowest values in blue and black tanks. L*, however, decreased in all treatments throughout the experiment. C*ab increased significantly over the course of the experiment in fish kept in white tanks. Similar increases of C*ab were recorded in the other treatments but to a lesser extent. The use of black tanks during the cultivation of L. alexandri caused stress and should be avoided. Cultivation in white and yellow tanks produced individuals with a pale skin colour, while cultivation in blue and black tanks resulted in juveniles with a darker and more pigmented skin.


Asunto(s)
Bagres/crecimiento & desarrollo , Pigmentación de la Piel/fisiología , Animales , Ambiente , Agua Dulce , Hidrocortisona/sangre
9.
J Med Case Rep ; 10: 196, 2016 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-27423470

RESUMEN

BACKGROUND: Duodenal Peutz-Jeghers polyp is a rare cause of duodenal or biliary obstruction. However, a sporadic Peutz-Jeghers polyp leading to simultaneous biliary and duodenal obstruction has not been reported. CASE PRESENTATION: We report a case of a 25-year-old Sri Lankan woman presenting with features of recurrent upper small intestinal obstruction and biliary obstruction. She had clinical as well as biochemical evidence of intermittent biliary obstruction. Evidence of duodenal intussusception was found in a computed tomography enterogram and a duodenal polyp was noted as the lead point. Marked elongation and distortion of her lower common bile duct with intrahepatic duct dilatation was also noted and the ampulla was found to be on the left side of the midline pulled toward the intussusceptum. Open polypectomy and reduction of intussusception were done and she became fully asymptomatic following surgery. Histology of the resected specimen was reported as a typical "Peutz-Jeghers polyp". As there was not enough evidence to diagnose Peutz-Jeghers syndrome this was considered to be a sporadic Peutz-Jeghers polyp. CONCLUSION: Rare benign causes such as a duodenal polyp should be considered and looked for in initial imaging, when the cause for concurrent biliary and intestinal obstruction is uncertain, particularly in young individuals.


Asunto(s)
Enfermedades Duodenales/etiología , Obstrucción Intestinal/etiología , Pólipos Intestinales/complicaciones , Intususcepción/etiología , Síndrome de Peutz-Jeghers/complicaciones , Adulto , Enfermedades Duodenales/diagnóstico por imagen , Enfermedades Duodenales/fisiopatología , Duodeno/diagnóstico por imagen , Duodeno/fisiopatología , Femenino , Humanos , Obstrucción Intestinal/diagnóstico por imagen , Obstrucción Intestinal/fisiopatología , Pólipos Intestinales/diagnóstico por imagen , Pólipos Intestinales/fisiopatología , Intestino Delgado/diagnóstico por imagen , Intestino Delgado/fisiopatología , Intususcepción/diagnóstico por imagen , Intususcepción/fisiopatología , Síndrome de Peutz-Jeghers/diagnóstico por imagen , Síndrome de Peutz-Jeghers/fisiopatología , Tomografía Computarizada por Rayos X
10.
Ceylon Med J ; 61(1): 18-21, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27031974

RESUMEN

INTRODUCTION: Growth hormone releasing hormone receptor (GHRH-R) codon 72 mutation is recognised as a common genetic cause of growth hormone deficiency (GHD) in the Indian subcontinent resulting in a characteristic lean phenotype. Genetic studies have not been previously carried out in Sri Lankans with GHD. METHODS: Patients with GHD presenting to a tertiary care referral centre were studied for GHRH-R codon 72 mutation by PCR amplification and sequencing. The phenotype of the cohort was described as the BMI SDS (Body mass index standard deviation score) based on the anthropometric data at the time of diagnosis. RESULTS: Among 91 patients from 88 families studied, eight (6 boys) carried the codon 72 mutation. The presence of this mutation was low among the Sinhalese ethnicity (3 out of 68) than among Tamil and Moor ethnicities. BMI SDS of <-2 was seen in 71% of mutation positive and 45.8% of mutation negative patients. CONCLUSIONS: Prevalence of GHRH-R codon 72 mutation in this group of GH deficient patients was 8.8%. The lean phenotype observed in 71% of the mutation positive patients was not a significant association when compared to a similar phenotype in 45.8% of the mutation negative patients.


Asunto(s)
Índice de Masa Corporal , Hormona del Crecimiento/deficiencia , Receptores de Neuropéptido/genética , Receptores de Hormona Reguladora de Hormona Hipofisaria/genética , Delgadez/genética , Adolescente , Niño , Preescolar , Codón , Estudios de Cohortes , Femenino , Humanos , Masculino , Mutación , Fenotipo , Sri Lanka , Adulto Joven
11.
Biol Trace Elem Res ; 163(1-2): 67-72, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25395121

RESUMEN

Brazil nut is the richest known food source of selenium. The supplementation with Brazil nut during 3 months was effective in reducing oxidative stress and inflammation in hemodialysis (HD) patients. However, there are no available data on the antioxidant effect after that supplementation. The objective of this work was to determine if the beneficial effects of one Brazil nut supplementation per day during 3 months for the HD patients could be sustained after 12 months. Twenty-nine HD patients (58.6 % men, 51.0 ± 3.3 years) from RenalCor Clinic, Rio de Janeiro, Brazil, were followed up 12 months after the supplementation study had finished. The plasma levels of antioxidant substances as selenium, glutathione peroxidase (GPx), 8-isoprostane, 8-hydroxy-2-deoxyguanosine (8-OHdG) and cytokines (tumour necrosis factor alpha (TNF-α) and interleukin-6 (IL-6)) were determined before, after 3 months of supplementation and after 12 months. After 3-months supplementation, cytokines, 8-OHdG and 8-isoprostane plasma levels have decreased and the activity of GPx and selenium plasma levels have increased significantly. Additionally, after 12 months, the values of 8-isoprostane, 8-OHdG and cytokines increased and the activity of GPx and selenium plasma levels decreased significantly. The levels of oxidative stress and inflammation biomarkers after 12 months increased compared to the basal levels. Consequently, it is necessary to motivate patients to adopt different dietary intake patterns.


Asunto(s)
Antioxidantes/metabolismo , Bertholletia , Suplementos Dietéticos , Diálisis Renal , Insuficiencia Renal Crónica , Citocinas/sangre , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Estrés Oxidativo , Insuficiencia Renal Crónica/sangre , Insuficiencia Renal Crónica/terapia , Selenio/administración & dosificación
12.
Insect Biochem Mol Biol ; 34(1): 19-27, 2004 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-14723894

RESUMEN

The H+-PPase activity was characterized in membrane fractions of ovary and eggs of Rhodnius prolixus. This activity is totally dependent on Mg2+, independent of K+ and strongly inhibited by NaF, IDP and Ca2+. The membrane proteins of eggs were analyzed by western blot using antibodies to the H+-PPase from Arabidopsis thaliana. The immunostain was associated with a single 65-kDa polypeptide. This polypeptide was immunolocalized in yolk granule membranes by optical and transmission electron microscopy. We describe the acidification of yolk granules in the presence of PPi and ATP. This acidification is inhibited in the presence of NAF, Ca2+ and antibodies against H+-PPase. These data show for the first time in animal cells that acidification of yolk granules involves an H+-PPase as well as H+-ATPase.


Asunto(s)
Difosfatos/metabolismo , Pirofosfatasa Inorgánica/metabolismo , Bombas de Protones/metabolismo , Rhodnius/enzimología , Adenosina Trifosfato/metabolismo , Animales , Western Blotting , Membrana Celular/enzimología , Proteínas del Huevo/metabolismo , Femenino , Cinética , Proteínas de la Membrana/metabolismo , Microscopía Electrónica , Oocitos/enzimología , Ovario/enzimología , Óvulo/enzimología
13.
J Exp Bot ; 52(359): 1191-201, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11432937

RESUMEN

Hexose phosphorylation by hexokinases plays an important role in glycolysis, biosynthesis and control of sugar-modulated genes. Several cytosolic hexokinase and fructokinase isoforms have been characterized and organelle-bound hexokinases have also been detected in higher plants. In this study a hexokinase activity is described that is inhibited by ADP (K(i)=30 microM) and mannoheptulose (K(i) congruent with 300 microM) in non-cytosolic fractions (mitochondria, Golgi apparatus and microsomes) obtained from preparations of seedling roots of maize (Zea mays L.). The catalytic efficiency (Vmax/Km) for both ATP and glucose in all non-cytosolic hexokinase fractions is more than one order of magnitude higher than that of cytosolic hexokinase and fructokinases. Low (30%) or no ADP and mannoheptulose inhibition is observed with hexokinase and fructokinase activities derived from the cytosolic compartment obtained after ion exchange and affinity chromatography. The soluble fructokinase (FK) shows fructose cooperativity (Hill n>2). The Vmax/Km ratio is about 3-fold higher for ATP than for other NTPs and no difference for hexose phosphorylation efficiencies is found between cytosolic hexokinase and fructokinase isoforms (FK1, FK2) with ATP as substrate. The K(i) for fructose inhibition is 2 mM for FK1 and 25 mM for FK2. The data indicate that low energy-charge and glucose analogues preferentially inhibit the membrane-bound hexokinases possibly involved in sugar-sensing, but not the cytosolic hexokinases and fructokinases.


Asunto(s)
Hexoquinasa/metabolismo , Hexosas/metabolismo , Raíces de Plantas/enzimología , Zea mays/enzimología , Adenosina Difosfato/metabolismo , Adenosina Trifosfato/metabolismo , Citosol/enzimología , Inhibidores Enzimáticos/farmacología , Fructoquinasas/metabolismo , Fructosa/metabolismo , Glucosa/análogos & derivados , Glucosa/metabolismo , Aparato de Golgi/enzimología , Aparato de Golgi/metabolismo , Hexoquinasa/antagonistas & inhibidores , Cinética , Mitocondrias/enzimología , Mitocondrias/metabolismo
14.
Phytochemistry ; 53(1): 29-37, 2000 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-10656404

RESUMEN

Two pools of hexokinase activities differing in sensitivity to ADP inhibition were characterised in maize roots. In order to evaluate how glucose utilisation could be affected by these hexokinases, glucose-6-P and NDP-5'-sugar levels were measured after a D-[U-14C]glucose pulse in root extracts in the presence of 0 or 1 mM ADP. Analysis of radio-labelled activated sugars by paper chromatography revealed that: (1) without ADP, nearly 20% of the 14C appeared in NDP-5'-sugars; (2) 0.1 mM ADP inhibited 14C-NDP-5'-sugar formation by 85%; and (3) with 1 mM ADP, 14C-NDP-5'-sugars were undetectable, but substantial (14%) 14C accumulated as glucose-6-P. Mannoheptulose, a hexokinase inhibitor, blocked the NDP-5'-sugar formation, but did not modify the amount of 14C-glucose-6-P in root extracts either with or without ADP. The analysis of the hexokinase activities with 0.8 mM glucose in maize root extracts showed that: (1) mitochondrial hexokinase activity was totally inhibited by 30 mM mannoheptulose; and (2) the cytosolic hexokinase was inhibited by only 30%. These data suggest that NDP-5'-sugar synthesis is sensitive to ADP fluctuations and that mannoheptulose affects preferentially the mitochondrial-bound hexokinase, but the cytosolic form is less sensitive. We propose that the mitochondrial hexokinase is the main energy charge sensor in this pathway in maize.


Asunto(s)
Glucosa-6-Fosfato/biosíntesis , Hexoquinasa/metabolismo , Azúcares de Nucleósido Difosfato/biosíntesis , Zea mays/metabolismo , Adenosina Difosfato/metabolismo , Glucosa/metabolismo , Manoheptulosa/metabolismo , Mitocondrias/metabolismo , Raíces de Plantas/metabolismo
15.
Planta Med ; 54(1): 37-9, 1988 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17265197

RESUMEN

A new dimeric indoline alkaloid has been isolated from the leaves of PETCHIA CEYLANICA. Its structure has been assigned as 1 on the basis of spectral studies. Its stereochemistry has been established by NOE difference measurements.

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