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1.
Oral Maxillofac Surg ; 24(4): 461-468, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32638173

RESUMEN

OBJECTIVE: The aim of this study was to determine if the timing of administration of systemic enzyme therapy [SET] has any effect on its efficacy in controlling postoperative sequelae of third molar surgery. STUDY DESIGN: A double blinded prospective randomized control trial was planned. The sample included patients requiring impacted mandibular third molar surgical extraction. Patients were randomly allocated to four groups (50 patients per group). Group A included administration of SET 48 h prior to surgery; Group B, started on the day of surgery; Group C started immediately after surgery and control group D included NSAIDS started 3 h after surgery. The predictor variable was timing of administration of SET. The primary outcome variables were pain and swelling measured on 1st day, 5th day, and 7th day after surgery. FINDINGS: Groups A and D reported lower mean and median VAS scores and lesser swelling than groups C and D on postop day 1. On days 5 and 7, all four groups were comparable. On overall analysis, no statistically significant difference (p > 0.05) was evident. INTERPRETATION: The results of the study showed that the differences in swelling and pain with starting the SET 2 days before, on the day of surgery, or immediately after when compared with diclofenac was not statistically significant. TRIAL REGISTRATION: CTRI Registration Number CTRI/2018/03/012502.


Asunto(s)
Diclofenaco , Diente Impactado , Diclofenaco/uso terapéutico , Método Doble Ciego , Edema/tratamiento farmacológico , Terapia Enzimática , Humanos , Tercer Molar/cirugía , Dolor Postoperatorio/tratamiento farmacológico , Péptido Hidrolasas/uso terapéutico , Estudios Prospectivos , Extracción Dental , Diente Impactado/cirugía
2.
Br J Oral Maxillofac Surg ; 58(8): 970-974, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32456996

RESUMEN

The aim of the study was to compare interpositional arthroplasty using a dermis fat graft with gap arthroplasty in the management of ankylosis of the temporomandibular joint (TMJ). We organised a prospective randomised study of 22 patients who presented with ankylosis of the TMJ. They were randomised to be treated with either plain gap arthroplasty or dermis fat arthroplasty, and the predictor variable was the method of treatment. The primary outcome variables were mouth opening and pain on jaw exercises. Pain and interincisal opening were measured on day 5, day 14, at the end of one month, and at six months, one year, two years, and three years. There was a significant difference between the two groups on two occasions: postoperative day 5 (p=0.013) and at one year (p=0.018). The mean (SD) scores for mouth-opening were higher in the dermis fat group at all times (41.20 (4.69) mm compared with 39.50 (2.46) mm in gap arthroplasty at two years, and 41.40 (3.60) mm compared with 38.9 (2.02) mm at three years). The visual analogue pain scores were also lower in the dermis fat graft group. The groups showed similar results at the end of three years follow up, with no significant difference in mouth opening. We conclude therefore that the two techniques have similar outcomes in the management of ankylosis of the TMJ.


Asunto(s)
Anquilosis , Trastornos de la Articulación Temporomandibular , Anquilosis del Diente , Anquilosis/cirugía , Artroplastia , Dermis , Humanos , Estudios Prospectivos , Articulación Temporomandibular/cirugía , Trastornos de la Articulación Temporomandibular/cirugía
3.
Oral Maxillofac Surg ; 22(4): 463-474, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30203137

RESUMEN

PURPOSE: Unilateral or bilateral ankylosis can lead to severe micrognathia and facial deformity that requires multiple, often, staged surgical corrections. To date, there is no ideal treatment modality that satisfactorily corrects the complex anatomy, restores the ramal height, and corrects the micrognathia and microgenia. Distraction osteogenesis has been acclaimed as a successful modality for the treatment of such deformities. It is a cost-effective approach with low morbidity and less relapse thus providing better functional and esthetic outcomes. It allows the surgeon to correct the deformity in various planes by using various devices by changing osteotomy designs and vectors, with simultaneous hard tissue and soft tissue reconstruction. PATIENTS AND METHODS: Here, we present a series of five cases where different types of distraction osteogenesis were combined with various other procedures to correct post-ankylotic facial asymmetry. In one case, simultaneous maxillo-mandibular distraction [Molina's technique] was used. RESULTS: All patients showed significant improvement in function and esthetics. Outcome assessment was made using clinical photographs and radiographs. CONCLUSION: Pre-arthroplastic distraction osteogenesis is a versatile cost effective approach that can be customized for every patient based on their needs.


Asunto(s)
Anquilosis/complicaciones , Asimetría Facial/etiología , Mandíbula/anomalías , Micrognatismo/etiología , Osteogénesis por Distracción/métodos , Trastornos de la Articulación Temporomandibular/complicaciones , Adolescente , Asimetría Facial/diagnóstico por imagen , Asimetría Facial/cirugía , Femenino , Humanos , Masculino , Mandíbula/diagnóstico por imagen , Mandíbula/cirugía , Micrognatismo/diagnóstico por imagen , Micrognatismo/cirugía , Radiografía , Resultado del Tratamiento , Adulto Joven
4.
J Stomatol Oral Maxillofac Surg ; 119(6): 510-513, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29883629

RESUMEN

The intramuscular haemangioma (IMH) is a rare variant of unknown aetiology and comprises 0.8% of soft tissue haemangiomas. Less than 20% of IMHs occur in the craniofacial region of which the masseter is the most common site. It presents as a non-specific, painful soft tissue enlargement in young adults. Symptoms common to vascular lesions usually are absent. Due to the paucity of clinical symptoms, advanced imaging techniques like MRIs are needed to clinch a definitive pre-operative diagnosis. The therapeutic modalities mentioned in the literature range from total surgical excision to non-surgical methods like cryotherapy, sclerotherapy, embolization and feeder vessel ligation. We present a case of an intra-massetric IMH in a 16-year-old male which was treated by total surgical excision with a follow up of 3 years. We also stress on the differential diagnosis of intra-massetric lesions and the key findings of the various imaging modalities available for IMH.


Asunto(s)
Hemangioma , Adolescente , Diagnóstico Diferencial , Humanos , Imagen por Resonancia Magnética , Masculino , Músculo Masetero , Escleroterapia
5.
Circulation ; 104(11): 1292-8, 2001 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-11551882

RESUMEN

BACKGROUND: Numerous pathological mediators of cardiac hypertrophy (eg, neurohormones, cytokines, and stretch) have been shown to activate p38 MAPK. The purpose of the present study was to examine p38 MAPK activation and the effects of its long-term inhibition in a model of hypertensive cardiac hypertrophy/dysfunction and end-organ damage. METHODS AND RESULTS: In spontaneously hypertensive stroke-prone (SP) rats receiving a high-salt/high-fat diet (SFD), myocardial p38 MAPK was activated persistently during the development of cardiac hypertrophy and inactivated during decompensation. Long-term oral treatment of SFD-SP rats with a selective p38 MAPK inhibitor (SB239063) significantly enhanced survival over an 18-week period compared with the untreated group (100% versus 50%). Periodic echocardiographic analysis revealed a significant reduction in LV hypertrophy and dysfunction in the SB239063-treatment groups. Little or no difference in blood pressure was noted in the treatment or vehicle groups. Basal and stimulated (lipopolysaccharide) plasma tumor necrosis factor-alpha concentrations were reduced in the SB239063-treatment groups. In vitro vasoreactivity studies demonstrated a significant preservation of endothelium-dependent relaxation in animals treated with the p38 MAPK inhibitor without effects on contraction or NO-mediated vasorelaxation. Proteinuria and the incidence of stroke (53% versus 7%) were also reduced significantly in the SB239063-treated groups. CONCLUSIONS: These results demonstrate a crucial role for p38 MAPK in hypertensive cardiac hypertrophy and end-organ damage. Interrupting its function with a specific p38 MAPK inhibitor halts clinical deterioration.


Asunto(s)
Cardiomegalia/fisiopatología , Hipertensión/fisiopatología , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Animales , Cardiomegalia/enzimología , Cardiomegalia/mortalidad , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Ecocardiografía , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/fisiopatología , Activación Enzimática , Corazón/efectos de los fármacos , Corazón/fisiopatología , Hemodinámica/efectos de los fármacos , Imidazoles/farmacología , Riñón/efectos de los fármacos , Riñón/fisiopatología , Lipopolisacáridos/farmacología , Masculino , Proteínas Quinasas Activadas por Mitógenos/antagonistas & inhibidores , Miocardio/metabolismo , Miocardio/patología , Fosforilación , Proteinuria/prevención & control , Proteinuria/orina , Pirimidinas/farmacología , Ratas , Ratas Endogámicas SHR , Ratas Endogámicas WKY , Accidente Cerebrovascular/patología , Accidente Cerebrovascular/prevención & control , Tasa de Supervivencia , Factores de Tiempo , Factor de Necrosis Tumoral alfa/efectos de los fármacos , Factor de Necrosis Tumoral alfa/metabolismo , Vasodilatación/efectos de los fármacos , Proteínas Quinasas p38 Activadas por Mitógenos
6.
Endocrinology ; 109(5): 1787-9, 1981 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-7028468

RESUMEN

When evaluated at 15 C, insulin binding to human erythrocytes is similar to that of human adipocytes fibroblasts, monocytes and placental membranes. At 37 C, however, both insulin binding and degradation by human erythrocytes have a unique character. At this temperature, by the end of the first 30 minutes, erythrocyte specific insulin binding is 3 to 4% of the total available insulin. This percentage of binding remains until the end of the first hour, then for the next four hours, increases linearly to 24%. Intact erythrocytes had negligible degradation of the free 125I-insulin but 56% of the 125I-insulin associated with the erythrocytes was degraded after five hours of incubation at 37 C. The degradation of the bound insulin was determined to be an intracellular property of erythrocytes. This degradation may be the mass action driving force responsible for the increased association of 125I-insulin observed after one hour of incubation. On the other hand, erythrocyte ghosts reached a steady state with 2% of the 125I-insulin bound after 1.5 hours of incubation at 37 C. More than 94% of the bound and free insulins were intact after 5 hours of incubation. These observations indicate, for the first time, that erythrocyte insulin degrading activity is localized inside the cells, not in their membranes, and that the human erythrocyte with its insulin receptors may be one of the important cell types in the metabolism of insulin.


Asunto(s)
Eritrocitos/metabolismo , Insulina/análogos & derivados , Receptor de Insulina/metabolismo , Membrana Eritrocítica/metabolismo , Humanos , Insulina/metabolismo , Cinética
7.
J Clin Pharmacol ; 32(10): 935-43, 1992 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-1447402

RESUMEN

Although pharmacokinetic and pharmacodynamic differences between the enantiomers of a chiral drug have been known or suspected for many years, racemate drugs have frequently been developed and approved without clinical pharmacologic consideration of their chiral components. In the late 1970s, the technology to isolate, manufacture, and detect pure enantiomers of racemate drugs became generally available. This availability has created new demands on both pharmaceutical firms and regulatory agencies. To prepare for this new technology, the Center for Drug Evaluation and Research at the Food and Drug Administration is formulating a policy statement to guide evaluation of new chiral drugs. At this time, it appears that whatever new policies are developed will not necessarily be applied retroactively to previously approved racemate drugs. Additional policies to guide the development and approval of generic and OTC chiral drugs may be required. In the Office of Generic Drugs in the Center, abbreviated new drug or antibiotic applications are approved on the basis of adequate chemistry, manufacturing, and control procedures and comparative pharmacokinetics (bioequivalence). The generic drug must be a racemate or single enantiomer if the corresponding innovator drug is a racemate or single enantiomer respectively. Whether a generic firm will be required to provide bioequivalence information on enantiomers of a racemate is determined on a case-by-case basis. Although it might be claimed that a generic drug product should be required only to undergo the same general kind of pharmaceutical evaluation as did the innovator, there may be instances when the approval of a generic drug or antibiotic will require measurement of specific enantiomers of a chiral drug.


Asunto(s)
Farmacocinética , Estereoisomerismo , Equivalencia Terapéutica , Aprobación de Drogas , Farmacología Clínica , Formulación de Políticas
8.
Clin Biochem ; 21(3): 163-5, 1988 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-3390905

RESUMEN

We report a modification of the technique of Mahoney et al. (Blood 1982; 59: 439) for the determination of sodium-22 (22Na+) uptake in human erythrocytes. This modification facilitates the separation of 22Na+ taken up by erythrocytes from the free 22Na+ in the buffer by the addition of dibutyl phthalate, which forms an immiscible layer between the two. To further improve the sensitivity of 22Na+ uptake, we incubated a range of known numbers of erythrocytes with 22Na+ as opposed to the single cell suspension of known hematocrit used in Mahoney's et al. procedure (1). Erythrocytes are incubated in KCI buffer containing 2627 Bq (0.071 microCi) 22Na+ in a total volume of 0.5 mL for 0.5 h at 37 degrees C. Incubation is terminated by placing the tubes in ice for 10 min and the amount of 22Na+ taken up by the erythrocytes determined. We observe a linear relationship between erythrocyte concentrations (0.5 to 2.5 X 10(9) cells/mL) and percent uptake of 22Na+ (0.37 +/- 0.06 (1 SD) to 1.85 +/- 0.27 (1 SD) of the total 22Na+, respectively). The procedure is simple and sensitive, and can be used in clinical laboratories for the routine evaluation of 22Na+ uptake in erythrocytes.


Asunto(s)
Eritrocitos/metabolismo , Ouabaína/farmacología , Sodio/sangre , Población Negra , Membrana Eritrocítica/efectos de los fármacos , Eritrocitos/efectos de los fármacos , Humanos , Técnicas In Vitro , Masculino , Cloruro de Potasio/farmacología , Radioisótopos de Sodio
9.
J Natl Med Assoc ; 77(2): 119-28, 1985 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-3981646

RESUMEN

Highly specific insulin receptors have been identified on the rat erythrocyte. A radioreceptor assay for the evaluation of these receptors has been developed, and the characteristics of these receptors have been investigated. Insulin receptor binding on the rat erythrocytes was found to be dependent on pH, temperature, time, and ionic strength. When incubated for 3½ hours at 15° C, 5.0 × 10(9) erythrocytes/mL from each of 10 rats were found to bind specifically 7.54 percent (±0.15 SEM) of 40 pg of (125)I-insulin. Specific binding was found to be a function of cell concentration. The pH optima for insulin binding were found to be 7.4 and 7.0 in the absence of cations. The presence of cations not only shifted pH optimum to 7.4 from 7.0, but also increased specific insulin binding.These observations suggest the stabilization of negatively charged groups on ligand and receptor, as well as providing a suitable ionic environment for the hormone-receptor interaction. Based on the resistance of rat erythrocytes to the pH of the external buffer, a simple method for determining the internal pH of rat red- blood cells is described. Scatchard analyses of insulin-binding data yielded curvilinear plots, and the number of receptor sites per cell was found to be 762 (±12.1 SD), as opposed to the large variation (410 ± 260 SD) in normal humans. The rat erythrocytes may serve as a useful, precise, sensitive, and efficient model system for future erythrocytic-receptor studies that would be difficult to obtain from human subjects.


Asunto(s)
Eritrocitos/metabolismo , Ensayo de Unión Radioligante , Receptor de Insulina/metabolismo , Animales , Masculino , Ratas , Ratas Endogámicas
10.
J Natl Med Assoc ; 75(5): 503-7, 1983 May.
Artículo en Inglés | MEDLINE | ID: mdl-6864830

RESUMEN

The authors established the specificity, reliability, and precision of human erythrocyte insulin radioreceptor assay. On the basis of insulin binding, cell viability, and degree of hemolysis, heparin sodium was found to be a more suitable anticoagulant than sodium fluoride, ethylenediaminetetraacetic acid, sodium oxalate, or sodium citrate. In two sets of experiments carried out at 4°C and 23°C, human erythrocytes were stored as whole blood or isolated erythrocytes suspended in Tris-{4-(2-hydroxyethyl)-1-piperazine-ethanesulfonic acid} buffer. The effect of storage under these conditions was evaluated by erythrocytespecific insulin binding. Human erythrocytes can be stored for 72 hours at 4°C without any change in insulin binding, insulin receptor sites per cell, or average affinity constant at the empty sites. Isolated erythrocytes can also be stored in plasma for 72 hours or in buffer G for 24 hours at 4°C without any change in insulin binding. It is not advisable to store human erythrocytes in plasma or as whole blood for more than 24 hours at 23°. These findings are useful in preserving insulin receptor activity when storage of erythrocytes is unavoidable.


Asunto(s)
Conservación de la Sangre/métodos , Eritrocitos/metabolismo , Receptor de Insulina/metabolismo , Anticoagulantes/metabolismo , Heparina/farmacología , Humanos , Ensayo de Unión Radioligante
11.
J Natl Med Assoc ; 74(4): 331-7, 1982 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-7120468

RESUMEN

Erythrocytes from human newborns were observed to have specific insulin receptors. The characteristics of these receptors were similar to those of the normal adult subjects. An observed slight increase in R(o) and a decrease in K̄(e) of insulin receptors in erythrocytes may be speculated to facilitate the transfer of insulin from the fetal erythrocytes to other rapidly growing fetal tissues at a rate faster than that present in the circulation of the adult subjects.


Asunto(s)
Eritrocitos/metabolismo , Recién Nacido , Receptor de Insulina/metabolismo , Adolescente , Adulto , Femenino , Sangre Fetal/metabolismo , Humanos
12.
Med Biol Eng Comput ; 32(6): 625-31, 1994 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-7723420

RESUMEN

In this paper, the limitations of the conventional formula for the computation of peripheral blood flow from impedance plethysmograms are highlighted, and a correction to the formula is suggested. A conductivity cell experiment is described to show the dependence of the value of the blood flow index (BFI), obtained from the conventional formula, on the mean resistivity of the cell. It is also shown that the value of the corrected BFI is independent of the mean resistivity. Anomalies observed in the amplitude of systolic waves in impedance plethysmograms of patients with oedema are explained.


Asunto(s)
Pierna/irrigación sanguínea , Pletismografía de Impedancia/métodos , Flujo Sanguíneo Regional , Adulto , Edema/fisiopatología , Reacciones Falso Positivas , Humanos , Matemática , Persona de Mediana Edad , Valores de Referencia
16.
Biomarkers ; 12(1): 87-112, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17438656

RESUMEN

The assessment of target organ damage is important in defining the optimal treatment of hypertension and blood pressure-related cardiovascular disease. The aims of the present study were (1) to investigate candidate biomarkers of target organ damage, osteopontin (OPN) and plasminogen activator inhibitor-1 (PAI-1), in models of malignant hypertension with well characterized end-organ pathology; and (2) to evaluate the effects of chronic treatment with a p38 MAPK inhibitor. Gene expression, plasma concentrations, and renal immunohistochemical localization of OPN and PAI-1 were measured in stroke-prone spontaneously hypertensive rats on a salt-fat diet (SFD SHR-SP) and in spontaneously hypertensive rats receiving N(omega)-nitro-L-arginine methyl ester (L-NAME SHR). Plasma concentrations of OPN and PAI-1 increased significantly in SFD SHR-SP and L-NAME SHR as compared with controls, (2.5-4.5-fold for OPN and 2.0-9.0-fold for PAI-1). The plasma levels of OPN and PAI-1 were significantly correlated with the urinary excretion of albumin (p < 0.0001). Elevations in urinary albumin, plasma OPN and PAI-1 were abolished by chronic treatment (4-8 weeks) with a specific p38 MAPK inhibitor, SB-239063AN. OPN immunoreactivity was localized predominantly in the apical portion of tubule epithelium, while PAI-1 immunoreactivity was robust in glomeruli, tubules and renal artery endothelium. Treatment with the p38 MAPK inhibitor significantly reduced OPN and PAI-1 protein expression in target organs. Kidney gene expression was increased for OPN (4.9- and 7.9-fold) and PAI-1 (2.8- and 11.5-fold) in SFD SHR-SP and L-NAME SHR, respectively. In-silico pathway analysis revealed that activation of p38 MAPK was linked to OPN and PAI-1 via SPI, c-fos and c-jun; suggesting that these pathways may play an important role in p38 MAPK-dependent hypertensive renal dysfunction. The results suggest that enhanced OPN and PAI-1 expression reflects end-organ damage in hypertension and that suppression correlates with end-organ protection regardless of overt antihypertensive action.


Asunto(s)
Biomarcadores/análisis , Hipertensión/metabolismo , Osteopontina/metabolismo , Inhibidor 1 de Activador Plasminogénico/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Quinasas p38 Activadas por Mitógenos/antagonistas & inhibidores , Animales , Ensayo de Inmunoadsorción Enzimática , Hipertensión/fisiopatología , Inmunohistoquímica , Masculino , Análisis de Secuencia por Matrices de Oligonucleótidos , Ratas , Ratas Endogámicas SHR
17.
Biochem Med Metab Biol ; 39(3): 284-9, 1988 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-3293635

RESUMEN

Using conventional techniques of ammonium sulfate fractionation and Sephadex gel column chromatography, insulin-degrading enzyme was partially purified from lysate of human erythrocytes. The enzymatic activity was measured by the trichloroacetic acid precipitation method. Compared to trypsin, the enzyme was highly specific for insulin. The apparent molecular weight of the enzyme was 160,000 Da, the optimum pH was the 7.4 to 7.8 range, and the Km value for insulin for the partially purified enzyme was 162 nM. Bacitracin and N-ethylmaleimide were potent inhibitors, while chloroquine, ethylenediaminetetraacetate, antipain, and soybean trypsin inhibitor failed to inhibit the activity of the enzyme. Like most nucleated cells, human erythrocytes not only have the membranal insulin receptors, but also possess the cytosolic specific insulin-degrading enzyme. Insulin internalization and degradation are shown to be due to the receptor and the enzyme acting in concert as in many nucleated cells. Anucleated erythrocytes have both these entities for possible internalization and degradation of insulin.


Asunto(s)
Eritrocitos/enzimología , Insulisina/sangre , Péptido Hidrolasas/sangre , Cromatografía en Gel , Citosol/enzimología , Humanos , Insulisina/aislamiento & purificación , Cinética , Especificidad por Sustrato
18.
Clin Chem ; 27(4): 607-9, 1981 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-7008973

RESUMEN

In vitro hemolysates of isolated human erythrocytes degrade 125I-labeled insulin. Ten- to 100-fold dilutions of the hemolysate give a proportionately decreased degradation of 125I-labeled insulin at 37 degrees C, while dilutions of up to eightfold do not. Like the control, diluted "Buffer G" containing 5 mmol/L Tris and 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid buffer alone, more than 500-fold dilutions of the hemolysate or boiled hemolysate (in buffer) caused negligible (less than 1%) degradation of the labeled insulin. We conclude that accurate insulin-binding data during erythrocyte insulin radioreceptor assay under optimum conditions (Clin. Chem. 23: 1590-1595, 1977) depend on avoiding or minimizing hemolysis.


Asunto(s)
Eritrocitos/metabolismo , Insulina/metabolismo , Hemólisis , Humanos , Técnicas In Vitro , Ensayo de Unión Radioligante
19.
Biochem Int ; 23(2): 405-12, 1991 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-1859440

RESUMEN

Internalization and degradation of insulin by human erythrocytes were studied. Erythrocytes were incubated with 125I-insulin at 4 degrees C, 15 degrees C, and 37 degrees C for varying time intervals. These erythrocytes were then subjected to a low pH wash to release bound insulin followed by TCA precipitation. After 4, 22, and 24 hours of insulin binding at 4 degrees C, 92 to 95% of the bound 125I-insulin was dissociable and 92 to 98% of the extractable insulin was undegraded. After 3.5 hours of incubation at 15 degrees, 82% of the bound insulin was dissociable and 60% of this was intact. However, after 60, 90, 120, and 180 minutes of incubation at 37 degrees C, only 42, 34, 24, and 37%, respectively, of the bound insulin was dissociable. The undissociated insulin in the 37 degrees C studies was considered to be intracellular. With increasing time of incubation at 37 degrees C, the extractability of cell bound insulin and the proportion of undegraded dissociable insulin were decreased. When 125I-insulin binding was 95% blocked by preincubating the erythrocytes with anti-insulin receptor antibody, 95% of the degradation of 125I-insulin was also blocked. These studies indicate that mature human erythrocytes degrade internalized insulin and this process is time, temperature, and insulin receptor dependent.


Asunto(s)
Eritrocitos/metabolismo , Insulina/sangre , Receptor de Insulina/metabolismo , Adulto , Anticuerpos Antiidiotipos , Humanos , Ensayo de Unión Radioligante , Receptor de Insulina/inmunología , Temperatura , Factores de Tiempo
20.
Uremia Invest ; 8(2): 103-9, 1984.
Artículo en Inglés | MEDLINE | ID: mdl-6399647

RESUMEN

Glucose tolerance does not improve to the normal level after dialysis; however, our studies showed that the insulin receptor binding to erythrocytes of nondiabetic patients with chronic renal failure (CRF) on hemodialysis was more than that in normal subjects. To understand this apparent anomaly in insulin receptor action and glucose metabolism, we investigated insulin degradation-a postreceptor event of insulin binding-in erythrocytes from CRF patients and compared it with that of normal subjects. We studied insulin degradation by erythrocytes from each of eight CRF patients and five normal subjects. The average hyperbolic insulin degradation curve for the CRF patients showed lower activity and a right-handed shift compared to the curve for the normal subjects. The average maximum degradation of insulin in the CRF patients was significantly lower than that of normal subjects. The number of erythrocytes required to produce 50% of maximum insulin degradation was significantly greater in these patients than that in the normal subjects. Furthermore, a linear correlation was observed between the duration of dialysis and maximum percent of insulin degradation in the CRF patients. Clinical implications of these findings are unclear at the present time. However, the insulin-degrading activity in erythrocytes may be reflective of that in other body tissues.


Asunto(s)
Eritrocitos/metabolismo , Insulina/sangre , Fallo Renal Crónico/sangre , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Receptor de Insulina/sangre , Diálisis Renal , Factores de Tiempo
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