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1.
Actas urol. esp ; 47(8): 527-534, oct. 2023. tab
Article in Spanish | IBECS | ID: ibc-226119

ABSTRACT

Objetivo En este estudio nos propusimos averiguar cuál es el momento óptimo para realizar la fijación testicular contralateral evaluando nuestros resultados de diez años en pacientes pospuberales con torsión testicular bajo un enfoque centrado en el paciente. Métodos Los pacientes pospuberales con diagnóstico de torsión testicular en un hospital terciario entre enero de 2012 y septiembre de 2022 se dividieron en dos grupos según los criterios del «enfoque centrado en el paciente» que adoptamos en nuestro centro. En el grupo1 se fijó el testículo contralateral en el mismo acto quirúrgico y en el grupo2 la fijación se realizó de forma diferida. Ambos grupos fueron examinados retrospectivamente, analizados estadísticamente y comparados. Resultados Un total de 41 pacientes se incluyeron en el estudio. En 19 (46,3%) de ellos se realizó fijación en el mismo acto, y en 22 (53,7%) se efectuó la fijación testicular contralateral de forma electiva. Se observó dehiscencia precoz de la herida en un paciente de cada grupo (4,5% grupo1 frente al 5,3% grupo2). En el periodo postoperatorio no se detectó atrofia ni torsión testicular contralateral en ningún grupo del estudio durante el seguimiento de 1año. Conclusión No existe ningún algoritmo para determinar el momento óptimo en que debe realizarse la fijación testicular contralateral en pacientes pospuberales con torsión testicular. Mediante enfoques centrados en el paciente, en los que se da prioridad a las características clínicas del paciente para determinar cuándo realizar la fijación testicular contralateral, se pueden obtener resultados que demuestran su eficacia y su seguridad (AU)


Objective In this study, we aimed to describe the timing of contralateral testicular fixation with our ten year results in postpubertal patients with testicular torsion with a patient-based approach. Methods Postpubertal patients diagnosed with testicular torsion in a tertiary hospital between January-2012 and September-2022 were divided into two groups according to the «patient-based approach» criteria we adopted in our clinic. Group1 in whom the contralateral teste was fixed in the same surgical act and group2 in whom the fixation was deferred. Both groups, were retrospectively examined, statistically analyzed and compared. Results A total of 41 patients were included in the study. Among those, 19 (46.3%) were fixed in the same act, and 22 (53.7%) underwent postponed elective contralateral testicular fixation. Early term wound dehiscence was observed in one patient in each group (4.5% group1 vs. 5.3% group2). In the postoperative period, no contralateral testicular atrophy or torsion was detected in the study groups during 1-year follow-up. Conclusion There is no algorithm for when contralateral testicular fixation should be performed in postpubertal patients with testicular torsion. Patient-based approaches, in which the clinical characteristics of the patient are prioritized in determining the timing of contralateral testicular fixation, can produce more effective and safe results (AU)


Subject(s)
Humans , Male , Adolescent , Young Adult , Spermatic Cord Torsion/surgery , Patient-Centered Care , Treatment Outcome , Time Factors
2.
Actas Urol Esp (Engl Ed) ; 47(8): 527-534, 2023 10.
Article in English, Spanish | MEDLINE | ID: mdl-37453494

ABSTRACT

OBJECTIVE: In this study, we aimed to describe the timing of contralateral testicular fixation with our ten year results in postpubertal patients with testicular torsion with a patient-based approach. METHODS: Postpubertal patients diagnosed with testicular torsion in a tertiary hospital between January-2012 and September-2022 were divided into 2 groups according to the "patient-based approach" criteria we adopted in our clinic. Group 1 in whom the contralateral teste was fixed in the same surgical act and group 2 in whom the fixation was deferred. Both groups, were retrospectively examined, statistically analyzed and compared. RESULTS: A total of 41 patients were included in the study. Among those, 19 (46.3%) were fixed in the same act, and 22 (53.7%) underwent postponed elective contralateral testicular fixation. Early term wound dehiscence was observed in one patient in each group (4.5% Group 1 vs. 5.3% Group 2). In the postoperative period, no contralateral testicular atrophy or torsion was detected in the study groups during 1-year follow-up. CONCLUSION: There is no algorithm for when contralateral testicular fixation should be performed in postpubertal patients with testicular torsion. Patient-based approaches, in which the clinical characteristics of the patient are prioritized in determining the timing of contralateral testicular fixation, can produce more effective and safe results.


Subject(s)
Spermatic Cord Torsion , Testis , Male , Humans , Testis/surgery , Spermatic Cord Torsion/surgery , Spermatic Cord Torsion/diagnosis , Retrospective Studies , Orchiectomy , Postoperative Complications/surgery
3.
J Colloid Interface Sci ; 606(Pt 1): 434-443, 2022 Jan 15.
Article in English | MEDLINE | ID: mdl-34411826

ABSTRACT

HYPOTHESIS: Even a small fraction of nanoparticles in fluids affects the splashing behavior of a droplet upon impact on a smooth surface. EXPERIMENTS: Nanofluid drop impact onto a smooth sapphire substrate is experimentally investigated over wide ranges of Reynolds (102

4.
Animal ; 10(10): 1689-96, 2016 Oct.
Article in English | MEDLINE | ID: mdl-27641929

ABSTRACT

The effect of maternal nutrition level during the periconception period on the muscle development of fetus and maternal-fetal plasma hormone concentrations in sheep were examined. Estrus was synchronized in 55 Karayaka ewes and were either fed ad libitum (well-fed, WF, n=23) or 0.5×maintenance (under-fed, UF, n=32) 6 days before and 7 days after mating. Non-pregnant ewes (WF, n=13; UF, n=24) and ewes carrying twins (WF, n=1) and female (WF, n=1; UF, n=3) fetuses were removed from the experiment. The singleton male fetuses from well-fed (n=8) and under-fed (n=5) ewes were collected on day 90 of gestation and placental characteristics, fetal BWs and dimensions, fetal organs and muscles weights were recorded. Maternal (on day 7 after mating) and fetal (on day 90 of pregnancy) blood samples were collected to analyze plasma hormone concentrations. Placental characteristics, BW and dimensions, organs and muscles weights of fetuses were not affected by maternal feed intake during the periconception period. Maternal nutrition level did not affect fiber numbers and the muscle cross-sectional area of the fetal longissimus dorsi (LD), semitendinosus (ST) muscles, but the cross-sectional area of the secondary fibers in the fetal LD and ST muscles from the UF ewes were higher than those from the WF ewes (P<0.05). Also, the ratio of secondary to primary fibers in the ST muscle were tended to be lower in the fetuses from the UF ewes (P=0.07). Maternal nutrition level during the periconception period did not cause any significant changes in fetal plasma insulin and maternal and fetal plasma IGF-I, cortisol, progesterone, free T3 and T4 concentrations. However, maternal cortisol concentrations were lower while insulin concentrations were higher in the WF ewes than those in the UF ewes (P<0.05). These results indicate that the reduced maternal feed intake during the periconception period may alter muscle fiber diameter without affecting fiber types, fetal weights and organ developments and plasma hormone concentrations in the fetus.


Subject(s)
Fetal Development/physiology , Maternal Nutritional Physiological Phenomena , Muscle Development/physiology , Muscle Fibers, Skeletal/physiology , Pregnancy, Animal , Sheep/physiology , Animals , Eating , Female , Fertilization , Hormones/blood , Hydrocortisone/blood , Insulin/blood , Insulin-Like Growth Factor I/analysis , Male , Pregnancy , Progesterone/blood , Sheep/embryology
5.
Eur J Clin Microbiol Infect Dis ; 34(6): 1213-21, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25698311

ABSTRACT

The aim of this study was to determine the independent risk factors, morbidity, and mortality of central nervous system (CNS) infections caused by Listeria monocytogenes. We retrospectively evaluated 100 episodes of neuroinvasive listeriosis in a multinational study in 21 tertiary care hospitals of Turkey, France, and Italy from 1990 to 2014. The mean age of the patients was 57 years (range, 19-92 years), and 64% were males. The all-cause immunosuppression rate was 54 % (54/100). Forty-nine (49 %) patients were referred to a hospital because of the classical triad of symptoms (fever, nuchal rigidity, and altered level of consciousness). Rhombencephalitis was detected radiologically in 9 (9 %) cases. Twenty-seven (64 %) of the patients who had cranial magnetic resonance imaging (MRI) performed had findings of meningeal and parenchymal involvement. The mean delay in the initiation of specific treatment was 6.8 ± 7 days. Empiric treatment was appropriate in 52 (52 %) patients. The mortality rate was 25 %, while neurologic sequelae occurred in 13 % of the patients. In the multivariate analysis, delay in treatment [odds ratio (OR), 1.07 [95 % confidence interval (CI), 1.01-1.16]] and seizures (OR, 3.41 [95 % CI, 1.05-11.09]) were significantly associated with mortality. Independent risk factors for neurologic sequelae were delay in treatment (OR, 1.07 [95 % CI, 1.006-1.367]) and presence of bacteremia (OR, 45.2 [95 % CI, 2.73-748.1]). Delay in the initiation of treatment of neuroinvasive listeriosis was a poor risk factor for unfavorable outcomes. Bacteremia was one of the independent risk factors for morbidity, while the presence of seizures predicted worse prognosis. Moreover, the addition of aminoglycosides to ampicillin monotherapy did not improve patients' prognosis.


Subject(s)
Listeria monocytogenes/isolation & purification , Meningitis, Listeria/diagnosis , Meningitis, Listeria/drug therapy , Adult , Aged , Aged, 80 and over , Anti-Bacterial Agents/therapeutic use , Cohort Studies , Female , France , Humans , Italy , Male , Meningitis, Listeria/epidemiology , Meningitis, Listeria/pathology , Middle Aged , Mortality , Prognosis , Retrospective Studies , Risk Factors , Survival Analysis , Tertiary Care Centers , Treatment Outcome , Turkey , Young Adult
8.
Acta Anaesthesiol Scand ; 54(5): 557-61, 2010 May.
Article in English | MEDLINE | ID: mdl-19919580

ABSTRACT

BACKGROUND: Although various local anesthesia techniques have been suggested to decrease pain and discomfort during a transrectal ultrasound (TRUS)-guided prostate biopsy, the best method has not yet been defined. The present prospective, double-blind, randomized study aims to investigate the clinical efficacy of 'walking' caudal block compared with an intrarectal lidocaine gel for this procedure. METHODS: One hundred patients were randomly assigned to two groups. In the lidocaine gel group, 10 ml of gel containing 2% lidocaine was given intrarectally. In the caudal group, 20 ml 0.1% bupivacaine with 75 microg fentanyl was injected. Pain scores, anal sphincter tone and patient satisfaction were evaluated. RESULTS: The pain scores were significantly lower in the caudal group at all stages. Verbal rating scores (scale 1-4) during probe insertion, probe maneuver and biopsies were 1 (0-2), 1 (0-2) and 1 (0-2) vs. 3 (0-5), 2 (1-3) and 4 (2-6), respectively (P value <0.0001 at all stages). The anal sphincter was more relaxed in the caudal group than in the gel group (P value <0.0001 in all categories). Highly satisfied patients were more frequently encountered in the caudal group, 34 (68%) vs. 8 (16%), P<0.0001, and unsatisfied patients were more frequently found in the gel group 1 (2%) vs. 12 (24%); P<0.001. All patients were able to walk without any assistance immediately after the procedures. CONCLUSION: 'Walking' caudal analgesia is an efficacious method for relieving the pain during TRUS-guided prostate biopsies in ambulatory practice.


Subject(s)
Anesthesia, Caudal/methods , Anesthetics, Local/administration & dosage , Bupivacaine/administration & dosage , Lidocaine/administration & dosage , Prostate/pathology , Aged , Ambulatory Care , Analgesics, Opioid/therapeutic use , Biopsy , Double-Blind Method , Fentanyl/therapeutic use , Humans , Male , Pain Measurement , Patient Satisfaction , Prospective Studies , Ultrasound, High-Intensity Focused, Transrectal/methods
9.
J Oral Rehabil ; 35(12): 934-9, 2008 Dec.
Article in English | MEDLINE | ID: mdl-19090910

ABSTRACT

Detection of progression level of peri-implantitis may help in the prevention of oral implant failure. C-telopeptide pyridinoline crosslinks of Type I collagen (ICTP) and osteocalcin (OC) are specific markers of bone turnover and bone degradation. Determination of the ICTP and OC levels in the peri-implant sulcus fluid (PISF) may predict the metabolic and/or inflammatory changes in the peri-implant bone. The aim of this clinical study was to evaluate ICTP and OC levels in the PISF for oral implants with and without peri-implant bone destruction and correlate these levels with the traditional clinical peri-implant parameters (probing depth, plaque index, gingival index and gingival bleeding time index) and radiographic bone level measurements. Fifteen patients with 30 peri-implant sites with bone destruction (radiographic bone loss) and health were included. Clinical parameters were measured and PISF was collected from the sites. Peri-implant sulcus fluid ICTP and OC levels were detected by radioimmunoassay technique from PISF samples. All clinical parameters demonstrated a significant increase in peri-implantitis sites compared with healthy sites. The PISF volume of the peri-implantitis sites was also significantly higher than of the healthy peri-implant sites. Although not statistically significant, a trend of increase was demonstrated in ICTP PISF samples sampled from peri-implantitis sites compared with healthy sites. A significant increase was noticed for OC PISF level in peri-implantitis sites compared with healthy ones. As well as peri-implant clinical measurements, volumetric changes at PISF may be counted as an important clinical parameter to distinguish the bone destruction sites from healthy sites around oral implants.


Subject(s)
Bone Resorption/metabolism , Collagen Type I/metabolism , Dental Implantation, Endosseous/adverse effects , Osteocalcin/metabolism , Peptides/metabolism , Periodontitis/metabolism , Adult , Bone Resorption/diagnostic imaging , Bone Resorption/etiology , Female , Humans , Male , Periodontitis/diagnostic imaging , Periodontitis/etiology , Radiography
10.
Andrologia ; 40(1): 38-43, 2008 Feb.
Article in English | MEDLINE | ID: mdl-18211300

ABSTRACT

In the present study, we aimed to evaluate the effects of dehydroepiandrosterone (DHEA) on apoptosis of testicular germ cells after repair of testicular torsion in rats. Twenty-four adult male Sprague-Dawley rats were randomly divided into four groups, with six rats in each group: sham operation, torsion/detorsion (T/D), T/D + vehicle, and T/D + DHEA. Three hours before detorsion, 50 mg kg(-1) DHEA was given intraperitoneally to T/D + DHEA group. In all groups, bilateral orchiectomies were performed and both testicles were histologically examined, with apoptosis detected using the in situ DNA fragmentation [terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL)] system, with morphological damage detected using a four-level grading scale in each specimen. The testes of the sham group showed a normal histology. In T/D and T/D + vehicle groups, apoptotic spermatogonia and spermatocyte number were significantly higher than in the sham group (P < 0.01 for all). The T/D + DHEA group showed a reduction in apoptotic spermatocyte and spermatogonia number in seminiferous epithelia compared with T/D group (P < 0.01 for both). Apoptotic cell number of contralateral testes did not reveal any significant differences among these groups (P > 0.05). Specimens from T/D and T/D + vehicle had a significantly greater histological injury than sham and T/D + DHEA groups in the ipsilateral testes (P < 0.01 for both). Therefore, the results suggest that DHEA may be a protective agent for preventing apoptosis caused by testicular torsion.


Subject(s)
Apoptosis/drug effects , Dehydroepiandrosterone/therapeutic use , Reperfusion Injury/prevention & control , Spermatic Cord Torsion/drug therapy , Animals , Dehydroepiandrosterone/pharmacology , Germ Cells/drug effects , Male , Rats , Rats, Sprague-Dawley , Spermatic Cord Torsion/pathology , Testis/pathology
12.
Arch Androl ; 52(4): 319-23, 2006.
Article in English | MEDLINE | ID: mdl-16728348

ABSTRACT

Male rats were equally divided into trained rest (TR), trained exhaustive exercise (TE), untrained rest (UR), and untrained exhaustive exercise (UE). Endurance training consisted of treadmill running for 1.5 h/d, 5 days a week for 8 weeks reaching the speed of 2.1 km/h at the fortieth week. For acute exhaustive exercise, graded treadmill running was conducted reaching the speed of 2.1 km/h at 95th min, 10% uphill, continued until exhaustion. Testicular tissue malondialdehyde (MDA), antioxidant potential (AOP) levels, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione-S-transferase (GST), glutathione reductase (GR) and catalase (CAT) activities were determined. There was a slight decrease, but not significant, in the SOD activity in UE group compared to TE and TR groups. Activity of GSH-Px decreased in the UE group compared to UR, TR and TE groups. Acute exhaustive exercise did not affect testicular tissue GSH-Px activity in trained rats. Testicular tissue GST activity of the UE group was similar to TE group, but lower than UR and TR groups. In UE group, testicular tissue AOP values were lower than UR, TR and TE groups. The oxidative effects of acute exhaustive exercise on the rat testis decreased with endurance training. Endurance training prevents oxidative injuries by eliminating oxygen radicals and inhibiting lipid peroxidation via preventing decreases in antioxidant enzyme activities.


Subject(s)
Antioxidants/metabolism , Lipid Peroxidation/physiology , Physical Conditioning, Animal , Physical Endurance/physiology , Testis/physiology , Animals , Male , Oxidative Stress , Rats , Rats, Sprague-Dawley , Weight Gain
13.
J Endocrinol Invest ; 28(8): 704-10, 2005 Sep.
Article in English | MEDLINE | ID: mdl-16277166

ABSTRACT

Previous studies showed that subclinical hypothyroidism (SH) was associated with cardiovascular disorders, such as endothelial dysfunction, atherosclerosis and myocardial dysfunction. Only one study investigated left ventricular (LV) function using pulsed tissue Doppler echocardiography (TDE) in patients with SH. However, no study has used this technique in the identification of right ventricular (RV) function in these patients. We aimed to investigate the effect of SH on RV and LV function using TDE technique. The present study included 36 newly diagnosed SH patients and 28 healthy controls. For each subjects, serum free T3 (FT3), free T4 (FT4), total T3 (TT3), total T4 (TT4), TSH, peroxidase antibody (TPOab) and thyroglobulin antibody (TGab) levels were measured, and standard echocardiography and TDE were performed. In patients with SH, TSH levels were significantly higher, and TPOab and TGab levels were significantly higher when compared to healthy controls. TDE showed that the patients had significantly lower early diastolic mitral and tricuspid annular velocity (Ea) and early/late (Ea/Aa) diastolic mitral and tricuspid annular velocity ratio (p<0.05, p<0.05 and p<0.001, p<0.001, respectively), and significantly longer isovolumetric relaxation time (IRT) of left and right ventricles (p<0.001 and p<0.001, respectively). However, Aa, Sa, and isovolumetric contraction time (ICT) and ET (ejection time) of left and right ventricle did not significantly differ (p=ns for all). In addition, a negative correlation between TSH and TD-derived tricuspid Ea velocity and Ea/Aa ratio, and a positive correlation between TSH and IRT of right ventricle were observed. Our findings demonstrated that SH is associated with impaired RV diastolic function in addition to impaired LV diastolic function.


Subject(s)
Heart/physiopathology , Hypothyroidism/physiopathology , Adult , Echocardiography, Doppler, Pulsed , Female , Humans , Hypothyroidism/blood , Male , Thyrotropin/blood , Thyroxine/blood , Triiodothyronine/blood , Ventricular Function, Left/physiology , Ventricular Function, Right/physiology
14.
J Int Med Res ; 30(3): 346-52, 2002.
Article in English | MEDLINE | ID: mdl-12166355

ABSTRACT

This study reviews urinary hydatid disease in seven males and three females (mean age, 32.1 +/- 17.7 years; range, 7-67 years). Cysts were located in the kidney in six cases (one also involved the liver), the paravesical and retrovesical region in two cases (one coexisted with a bladder tumour), the adrenal gland (one case) and in the right parapelvic region (one case). Investigations included urinalysis, eosinophil count, Casoni skin test, indirect haemagglutination test (IHA), abdominal ultrasonography, intravenous urography and computed tomography (CT). All patients underwent surgery and were followed for an average of 5.6 years. Lumbar or abdominal pain was the most common symptom. Eosinophilia was seen in five patients (50%), IHA positivity occurred in four patients (40%) and the Casoni skin test was positive in four patients (40%). Abdominal CT was the most useful diagnostic method of radiological investigation (100%). No complications or recurrences were seen on follow-up. Urinary hydatid disease is uncommon and is likely to cause considerable diagnostic difficulties, and should therefore be considered in the differential diagnosis of space-occupying lesions of the urinary tract.


Subject(s)
Echinococcosis/surgery , Urinary Tract Infections/surgery , Adolescent , Adult , Aged , Child , Echinococcosis/diagnostic imaging , Female , Humans , Male , Middle Aged , Retrospective Studies , Tomography, X-Ray Computed , Urinary Tract Infections/diagnostic imaging
15.
Arch Androl ; 48(3): 181-5, 2002.
Article in English | MEDLINE | ID: mdl-11964210

ABSTRACT

There is an inverse correlation between seminal plasma nitric oxide (NO) concentration and sperm parameters (motility and concentration) in patients with varicocele. This study investigated whether this occurs in patients with oligo- and/or asthenozoospermia due to causes other than varicocele. A total of 69 (19 with varicocele and oligo- and/or asthenozoospermia [group 1], 30 from oligo- and/or asthenozoospermic ones without varicocele [group 2], and 20 from healthy subjects [control group]) semen samples were analyzed. While group 1 had a significantly higher NO concentration in the seminal plasma compared to both the control group and group 2, there was no significant difference between group 2 and the control group (p >.05). In group 1, but not in the other groups, there was an inverse correlation between the seminal plasma NO concentration and sperm motility and concentration. NO production could be specifically related to the varicocele, since NO production in oligo- and/or asthenozoospermia cases without varicocele is not increased.


Subject(s)
Nitric Oxide/metabolism , Oligospermia/metabolism , Semen/metabolism , Sperm Motility/physiology , Varicocele/metabolism , Adult , Humans , Male , Oligospermia/etiology , Oligospermia/pathology , Sperm Count , Varicocele/complications , Varicocele/pathology
16.
Ann Plast Surg ; 47(5): 523-7, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11716264

ABSTRACT

Presented here are 23 patients with Fournier's gangrene who were treated between 1990 and 1999 in the departments of general surgery, urology, and plastic and reconstructive surgery. Patients were reviewed retrospectively and are discussed according to age, gender, bacteriology, etiology, treatment, and outcome in the light of the current literature.


Subject(s)
Fournier Gangrene , Abdominal Muscles/surgery , Adult , Aged , Colostomy , Debridement , Fasciitis, Necrotizing/etiology , Fasciitis, Necrotizing/microbiology , Fasciitis, Necrotizing/therapy , Female , Fournier Gangrene/etiology , Fournier Gangrene/microbiology , Fournier Gangrene/therapy , Humans , Male , Middle Aged , Retrospective Studies , Surgical Flaps
17.
Int J Biochem Cell Biol ; 33(3): 221-6, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11311853

ABSTRACT

The kinetic properties of placental glucose-6-phosphate dehydrogenase were studied, since this enzyme is expected to be an important component of the placental protection system. In this capacity it is also very important for the health of the fetus. The placental enzyme obeyed "Rapid Equilibrium Ordered Bi Bi" sequential kinetics with K(m) values of 40+/-8 microM for glucose-6-phosphate and 20+/-10 microM for NADP. Glucose-6-phosphate, 2-deoxyglucose-6-phosphate and galactose-6-phosphate were used with catalytic efficiencies (k(cat)/K(m)) of 7.4 x 10(6), 4.89 x 10(4) and 1.57 x 10(4) M(-1).s(-1), respectively. The K(m)app values for galactose-6-phosphate and for 2-deoxyglucose-6-phosphate were 10+/-2 and 0.87+/-0.06 mM. With galactose-6-phosphate as substrate, the same K(m) value for NADP as glucose-6-phosphate was obtained and it was independent of galactose-6-phosphate concentration. On the other hand, when 2-deoxyglucose-6-phosphate used as substrate, the K(m) for NADP decreased from 30+/-6 to 10+/-2 microM as the substrate concentration was increased from 0.3 to 1.5 mM. Deamino-NADP, but not NAD, was a coenzyme for placental glucose-6-phosphate dehydrogenase. The catalytic efficiencies of NADP and deamino-NADP (glucose-6-phosphate as substrate) were 1.48 x 10(7) and 4.80 x 10(6) M(-1)s(-1), respectively. With both coenzymes, a hyperbolic saturation and an inhibition above 300 microM coenzyme concentration, was observed. Human placental glucose-6-phosphate dehydrogenase was inhibited competitively by 2,3-diphosphoglycerate (K(i)=15+/-3 mM) and NADPH (K(i)=17.1+/-3.2 microM). The small dissociation constant for the G6PD:NADPH complex pointed to tight enzyme:NADPH binding and the important role of NADPH in the regulation of the pentose phosphate pathway.


Subject(s)
Glucosephosphate Dehydrogenase/metabolism , NADP/metabolism , Placenta/enzymology , 2,3-Diphosphoglycerate/antagonists & inhibitors , 2,3-Diphosphoglycerate/metabolism , Coenzymes/metabolism , Humans , Kinetics , NADP/analogs & derivatives , NADP/antagonists & inhibitors , Substrate Specificity
19.
Protein Expr Purif ; 21(2): 286-92, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11237690

ABSTRACT

Glucose-6-phosphate dehydrogenase was purified from human placenta using DEAE-Sepharose fast flow, 2',5'-ADP Sepharose 4B column chromatography, and chromatofocusing on PBE 94 with PB 74. The enzyme was purified with 62% yield and had a specific activity of 87 units per milligram protein. The pH optimum was determined to be 7.8, using zero buffer extrapolation method. The purified placental glucose-6-phosphate dehydrogenase gave two activity bands on native PAGE: one band, constituting about 3--5% of total activity, moved slower than the remaining 95%. Among the activity bands only the faster moving band gave a band on protein staining. The slower moving band, which probably corresponded to the higher polymeric form of the G6PD with high specific activity, was not seen on native PAGE due to insufficient protein for Coomassie brilliant blue staining. The observation of one band on SDS--PAGE with an M(r) of 54 kDa and a specific activity lower than expected, suggests the presence of both forms of the G6PD, the high polymeric form at low concentration and the inactive form at high concentration, in our preparation. Measuring the activities of placental glucose-6-phosphate dehydrogenase between 20 and 50 degrees C, the activation energy, activation enthalpy, and Q(10) were calculated to be 8.16 kcal/mol, 7.55 kcal/mol, and 1.57, respectively. It was found that human placental G6PD obeys Michaelis-Menten kinetics. K(m) values were determined using the concentration ranges of 20--300 microM for G6P and 10--200 microM for NADP(+). The K(m) value for G6P was 40 microM; the K(m) value NADP(+) was found to be 20 microM. Double-reciprocal plots of 1/Vm vs 1/G6P (at constant [NADP(+)]) and of 1/Vm vs 1/NADP(+) (at constant [G6P]) intersected at the same point on the 1/V(m) axis to give V(m) = 87 U/mg protein.


Subject(s)
Glucosephosphate Dehydrogenase/isolation & purification , Glucosephosphate Dehydrogenase/metabolism , Placenta/enzymology , Chromatography, Affinity , Chromatography, Ion Exchange , Female , Glucosephosphate Dehydrogenase/chemistry , Humans , Hydrogen-Ion Concentration , Kinetics , Molecular Weight , Thermodynamics
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