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1.
Minerva Endocrinol ; 38(2): 165-72, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23732370

ABSTRACT

Obesity has become a national epidemic and a disease of global magnitude. The numbers of patients with obesity have grown exponentially in the last 10 years to the degree that the Centers for Disease Control and Prevention reports that one third of the US population is obese. The prevalence of diabetes has grown by more than 50% in that same time period. Unfortunately, the traditional therapies of diets, exercise, behavioral modification and medications have had little effect, especially in the severely obese. The introduction of bariatric surgery has changed the natural history of the super obese. Operative approaches now provide the most effective treatment of obesity but carry with them possible risks. Only 1% of patients who are estimated to benefit from bariatric surgery have undergone a procedure. The burgeoning field of endoluminal therapy has now allowed us to consider even more minimally invasive procedures to reach a larger patient population. This article will review the most recent advances in innovative technologies to treat the growing numbers of obese patients.


Subject(s)
Obesity/therapy , Behavior Therapy , Botulinum Toxins/administration & dosage , Botulinum Toxins/therapeutic use , Electric Stimulation Therapy , Endoscopy, Gastrointestinal , Gastric Balloon , Gastroplasty , Humans , Obesity/surgery , Stomach/physiopathology , Treatment Outcome , Vagus Nerve Stimulation
2.
Science ; 173(4001): 1035-6, 1971 Sep 10.
Article in English | MEDLINE | ID: mdl-4329180

ABSTRACT

A statistical correlationl was made between adrenocorticotropin (ACTH) and four elements in rats under control, stress, and stress-recovery conditions. Blood serum zinc showed a strong positive correlation with the rise in ACTH during stress and its decline in stress recovery. Serum calcium, copper, and magnesium demonstrated little correlation with ACTH changes. The strong ACTH-zinc correlation points to an as yet undefined interaction between ACTH and zinc


Subject(s)
Adrenocorticotropic Hormone/blood , Minerals/blood , Stress, Physiological/blood , Adrenal Glands/physiopathology , Animals , Calcium/blood , Copper/blood , Corticosterone/blood , Fluorometry , Hypotension/blood , Magnesium/blood , Male , Pituitary Gland/physiopathology , Rats , Spectrum Analysis , Stress, Physiological/physiopathology , Zinc/blood
3.
J Clin Invest ; 81(4): 976-81, 1988 Apr.
Article in English | MEDLINE | ID: mdl-2832449

ABSTRACT

Insulin-like growth factor-I (IGF-I) in human hepatoma cells (HEP-G2) has, in addition to its effect on cell growth, short-term metabolic effects acting through its own receptor. We have demonstrated that normal human hepatocytes, compared with HEP-G2 cells, have virtually no IGF-I binding sites. Because the rate of growth is the major difference between the hepatoma and the normal liver, we asked if normal liver might express IGF-I binding sites under physiologic growth conditions. Indeed, whereas adult rat hepatocytes have low IGF-I binding sites similar to those in human liver, hepatocytes from regenerating liver after 3 d subtotal hepatectomy have an approximately sixfold increase (P less than 0.005) and those from fetal rat liver a approximately 12-fold increase (P less than 0.005), to levels comparable to those in the HEP-G2 cells. The specificity of 125I IGF-I binding to its receptor was demonstrated by competition studies with monoclonal antibodies directed toward the IGF-I and the insulin receptors, with unlabeled IGF-I and insulin and by affinity labeling experiments. Thus, if IGF-I has any short-term metabolic functions in the adult human liver, it is not through interaction with its own receptor. Autocrine regulation by IGF-I of liver growth appears possible since IGF-I binding sites are expressed under pathological and physiological conditions of growth. The mechanism that couples these two phenomena remains to be elucidated.


Subject(s)
Carcinoma, Hepatocellular/metabolism , Insulin-Like Growth Factor I/metabolism , Liver/physiology , Somatomedins/metabolism , Animals , Cell Membrane/metabolism , Humans , Liver/embryology , Liver Neoplasms , Molecular Weight , Rats , Receptor, Insulin/metabolism , Receptors, Somatomedin
4.
J Clin Invest ; 82(2): 486-94, 1988 Aug.
Article in English | MEDLINE | ID: mdl-3403714

ABSTRACT

We have developed an in vitro muscle preparation suitable for metabolic studies with human muscle tissue and have investigated the effects of obesity and non-insulin-dependent diabetes mellitus (NIDDM) on glucose transport. Transport of 3-O-methylglucose and 2-deoxyglucose was stimulated approximately twofold by insulin in muscle from normal nonobese subjects and stimulation occurred in the normal physiological range of insulin concentrations. In contrast to insulin stimulation of 3-O-methylglucose and 2-deoxyglucose transport in muscle from normal, nonobese subjects, tissue from morbidly obese subjects, with or without NIDDM, were not responsive to insulin. Maximal 3-O-methylglucose transport was lower in muscle of obese than nonobese subjects. Morbidly obese patients, with or without NIDDM, have a severe state of insulin resistance in glucose transport. The novel in vitro human skeletal muscle preparation herein described should be useful in investigating the mechanism of this insulin resistance.


Subject(s)
Diabetes Mellitus, Type 2/metabolism , Glucose/metabolism , Insulin Resistance , Muscles/metabolism , Obesity, Morbid/metabolism , 3-O-Methylglucose , Adult , Biological Transport/drug effects , Deoxyglucose/metabolism , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/pathology , Female , Glucose Tolerance Test , Humans , In Vitro Techniques , Male , Methylglucosides/metabolism , Muscles/ultrastructure , Obesity, Morbid/complications , Obesity, Morbid/pathology , Time Factors
5.
J Clin Invest ; 78(1): 249-58, 1986 Jul.
Article in English | MEDLINE | ID: mdl-3522628

ABSTRACT

We have developed a method to isolate insulin-responsive human hepatocytes from an intraoperative liver biopsy to study insulin action and resistance in man. Hepatocytes from obese patients with noninsulin-dependent diabetes were resistant to maximal insulin concentration, and those from obese controls to submaximal insulin concentration in comparison to nonobese controls. Insulin binding per cell number was similar in all groups. However, insulin binding per surface area was decreased in the two obese groups because their hepatocytes were larger. In addition, the pool of detergent-extractable receptor was further decreased in diabetics. Insulin receptors in all groups were unaltered as determined by affinity-labeling methods. However, insulin-stimulated insulin receptor kinase activity was decreased in diabetics. Thus, in obesity, decreased surface binding could explain resistance to submaximal insulin concentrations. In diabetes, diminished insulin-stimulated protein kinase activity and decreased intracellular pool of receptors could provide an explanation for postinsulin-binding defect(s) of insulin action in human liver.


Subject(s)
Insulin Resistance , Insulin/metabolism , Liver/metabolism , Protein Kinases/metabolism , Receptor, Insulin/analysis , Biopsy , Cell Separation , Diabetes Mellitus/physiopathology , Electrophoresis, Polyacrylamide Gel , Humans , Kinetics , Obesity/physiopathology , Receptor, Insulin/metabolism , Structure-Activity Relationship
6.
J Clin Invest ; 79(5): 1330-7, 1987 May.
Article in English | MEDLINE | ID: mdl-3033021

ABSTRACT

We have studied the structure and function of the insulin receptors in obese patients with and without noninsulin dependent diabetes mellitus (NIDDM) and in nonobese controls using partially purified receptors from muscle biopsies. Insulin binding was decreased in obesity due to reduced number of binding sites but no differences were observed in insulin binding between obese subjects with or without NIDDM. The structural characteristics of the receptors, as determined by affinity labeling methods and electrophoretic mobility of the beta-subunit, were not altered in obese or NIDDM compared to normal weight subjects. Furthermore, the ability of insulin to stimulate the autophosphorylation of the beta-subunit and the phosphoamino acid composition of the phosphorylated receptor were the same in all groups. However, insulin receptor kinase activity was decreased in obesity using Glu4:Tyr1 as exogenous phosphoacceptor without any appreciable additional defect when obesity was associated with NIDDM. Thus, our data are supportive of the hypothesis that in muscle of obese humans, insulin resistance is partially due to decreased insulin receptors and insulin receptor kinase activity. In NIDDM the defect(s) in muscle is probably distal to the insulin receptor kinase.


Subject(s)
Diabetes Mellitus, Type 2/enzymology , Diabetes Mellitus/enzymology , Muscles/enzymology , Obesity/enzymology , Protein-Tyrosine Kinases/metabolism , Adult , Female , Humans , Insulin/metabolism , Insulin Resistance , Male , Phosphorylation , Receptor, Insulin
7.
J Clin Invest ; 80(4): 1073-81, 1987 Oct.
Article in English | MEDLINE | ID: mdl-3308958

ABSTRACT

We have tested the hypothesis that in vitro exposure of insulin-resistant adipocytes with insulin results in improved insulin action. A primary culture system of adipocytes from obese subjects with or without non-insulin-dependent diabetes mellitus (NIDDM) and nonobese control subjects has been developed. The adipocytes when cultured in serum-free medium do not lose their original characteristics in regard to insulin binding and glucose transport. The adipocytes from three groups were incubated with insulin (0, 10(-10) M, and 10(-7) M) for 24 h at 37 degrees C, receptor-bound insulin was dissociated, and basal and insulin (1 X 10(-11)-10(-7) M)-stimulated glucose transport and 125I-insulin binding were determined. The 24-h insulin exposure of adipocytes from control subjects decreased basal and insulin-stimulated glucose transport. The effects of 1 X 10(-7) M insulin were more pronounced than 1 X 10(-10) M insulin. Similarly, insulin exposure decreased insulin sensitivity and responsiveness of cultured adipocytes from obese and NIDDM patients. The insulin-induced reduction in insulin sensitivity and responsiveness for glucose transport in three groups were due to alterations at insulin binding and postbinding levels. In conclusion, insulin induces insulin resistance in control adipocytes and further worsens the insulin resistance of adipocytes from obese and NIDDM subjects. For insulin to improve the insulin resistance of adipocytes from NIDDM patients, either more prolonged in vitro insulin exposure and/or other hormonal factors might be required.


Subject(s)
Adipose Tissue/metabolism , Diabetes Mellitus, Type 2/metabolism , Glucose/metabolism , Insulin/metabolism , Insulin/pharmacology , Obesity/metabolism , Adipose Tissue/drug effects , Adult , Binding, Competitive , Cells, Cultured , Female , Humans , Insulin Resistance , Leucine/metabolism , Male
8.
J Clin Invest ; 99(10): 2416-22, 1997 May 15.
Article in English | MEDLINE | ID: mdl-9153284

ABSTRACT

The peroxisome proliferator activated receptor (PPAR gamma) plays a key role in adipogenesis and adipocyte gene expression and is the receptor for the thiazolidinedione class of insulin-sensitizing drugs. The tissue expression and potential for regulation of human PPAR gamma gene expression in vivo are unknown. We have cloned a partial human PPAR gamma cDNA, and established an RNase protection assay that permits simultaneous measurements of both PPAR gamma1 and PPAR gamma2 splice variants. Both gamma1 and gamma2 mRNAs were abundantly expressed in adipose tissue. PPAR gamma1 was detected at lower levels in liver and heart, whereas both gamma1 and gamma2 mRNAs were expressed at low levels in skeletal muscle. To examine the hypothesis that obesity is associated with abnormal adipose tissue expression of PPAR gamma, we quantitated PPARgamma mRNA splice variants in subcutaneous adipose tissue of 14 lean and 24 obese subjects. Adipose expression of PPARgamma 2 mRNA was increased in human obesity (14.25 attomol PPAR gamma2/18S in obese females vs 9.9 in lean, P = 0.003). This increase was observed in both male and females. In contrast, no differences were observed in PPAR gamma1/18S mRNA expression. There was a strong positive correlation (r = 0.70, P < 0.001) between the ratio of PPAR gamma2/gamma1 and the body mass index of these patients. We also observed sexually dimorphic expression with increased expression of both PPAR gamma1 and PPAR gamma2 mRNAs in the subcutaneous adipose tissue of women compared with men. To determine the effect of weight loss on PPAR gamma mRNA expression, seven additional obese subjects were fed a low calorie diet (800 Kcal) until 10% weight loss was achieved. Mean expression of adipose PPAR gamma2 mRNA fell 25% (P = 0.0250 after a 10% reduction in body weight), but then increased to pretreatment levels after 4 wk of weight maintenance. Nutritional regulation of PPAR gamma1 was not seen. In vitro experiments revealed a synergistic effect of insulin and corticosteroids to induce PPAR gamma expression in isolated human adipocytes in culture. We conclude that: (a) human PPAR gamma mRNA expression is most abundant in adipose tissue, but lower level expression of both splice variants is seen in skeletal muscle; to an extent that is unlikely to be due to adipose contamination. (b) RNA derived from adipose tissue of obese humans has increased expression of PPAR gamma 2 mRNA, as well as an increased ratio of PPAR gamma2/gamma1 splice variants that is proportional to the BMI; (c) a low calorie diet specifically down-regulates the expression of PPAR gamma2 mRNA in adipose tissue of obese humans; (d) insulin and corticosteroids synergistically induce PPAR gamma mRNA after in vitro exposure to isolated human adipocytes; and (e) the in vivo modulation of PPAR gamma2 mRNA levels is an additional level of regulation for the control of adipocyte development and function, and could provide a molecular mechanism for alterations in adipocyte number and function in obesity.


Subject(s)
Adipose Tissue/metabolism , Dexamethasone/pharmacology , Gene Expression , Insulin/pharmacology , Muscle, Skeletal/metabolism , Obesity, Morbid/physiopathology , Receptors, Cytoplasmic and Nuclear/biosynthesis , Transcription Factors/biosynthesis , Transcription, Genetic , Weight Loss/physiology , Adipose Tissue/drug effects , Adult , Cells, Cultured , Cloning, Molecular , DNA Primers , Diet, Reducing , Energy Intake , Female , Gene Expression/drug effects , Humans , Liver/metabolism , Male , Muscle, Skeletal/drug effects , Myocardium/metabolism , Nuclear Proteins/biosynthesis , Obesity, Morbid/diet therapy , Obesity, Morbid/metabolism , Polymerase Chain Reaction , Sex Characteristics , Thinness , Transcription, Genetic/drug effects
9.
Diabetes ; 49(8): 1353-8, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10923637

ABSTRACT

This study was conducted to investigate the possible involvement of protein kinase C (PKC) and serine/threonine phosphorylation of the insulin receptor in insulin resistance and/or obesity. Insulin receptor tyrosine kinase activity was depressed in muscle from obese insulin-resistant patients compared with lean insulin-responsive control subjects. Alkaline phosphatase treatment resulted in a significant 48% increase in in vitro insulin-stimulated receptor tyrosine kinase activity in obese but not lean muscle. To investigate the involvement of PKC in skeletal muscle insulin resistance and/or obesity, membrane-associated PKC activity and the protein content of various PKC isoforms were measured in human skeletal muscle from lean, insulin-responsive, and obese insulin-resistant patients. Membrane-associated PKC activity was not changed; however, PKC-beta protein content, assayed by Western blot analysis, was significantly higher, whereas PKC-theta, -eta, and -mu were significantly lower in muscle from obese patients compared with muscle from lean control subjects. Incubation of muscle strips with insulin significantly increased membrane-associated PKC activity in muscle from obese but not lean subjects. PKC-delta, -beta, and -theta were translocated from the cytosol to the membrane fraction in response to insulin treatment. These results suggest that in skeletal muscle from insulin-resistant obese patients, insulin receptor tyrosine kinase activity was reduced because of hyperphosphorylation on serine/threonine residues. Membrane-associated PKC-beta protein was elevated under basal conditions, and membrane-associated total PKC activity was increased under insulin-stimulated conditions in muscle from obese insulin-resistant patients. Thus, we postulate that the decreased tyrosine kinase activity of the insulin receptor may be caused by serine/threonine phosphorylation by PKC.


Subject(s)
Insulin Resistance/physiology , Muscle, Skeletal/physiopathology , Obesity/physiopathology , Protein Kinase C/metabolism , Receptor, Insulin/metabolism , Adult , Alkaline Phosphatase/metabolism , Blood Glucose/metabolism , Body Mass Index , Cell Membrane/enzymology , Fatty Acids, Nonesterified/blood , Female , Humans , Insulin/blood , Isoenzymes/metabolism , Male , Muscle, Skeletal/enzymology , Reference Values , Thinness
10.
Diabetes ; 44(6): 682-8, 1995 Jun.
Article in English | MEDLINE | ID: mdl-7789633

ABSTRACT

In response to insulin, several proteins are phosphorylated on tyrosine and on serine/threonine residues. Decreased phosphorylation of signaling peptides by a defective insulin receptor kinase may be a cause of insulin resistance. Accordingly, inhibition of the appropriate phosphatases might increase the phosphorylation state of these signaling peptides and thereby elicit increased glucose transport. The purpose of this study was to examine the effect of the serine/threonine phosphatase inhibitor okadaic acid and the tyrosine phosphatase inhibitors phenylarsine oxide and vanadate on 2-deoxyglucose transport in insulin-resistant human skeletal muscle. All three phosphatase inhibitors stimulated 2-deoxyglucose transport in insulin-resistant skeletal muscle. These data suggest that these compounds have bypassed a defect in at least one of the signaling pathways leading to glucose transport. Furthermore, maximal transport rates induced by the simultaneous presence of insulin and phosphatase inhibitor in insulin-resistant muscle were equal to insulin-stimulated rates in lean control subjects. However, both vanadate alone and vanadate plus insulin stimulated 2-deoxyglucose transport significantly more in insulin-sensitive tissue than in insulin-resistant tissue. These results demonstrate that although vanadate is able to stimulate glucose transport in insulin-resistant muscle, it is not able to normalize transport to the same rate achieved in insulin-sensitive muscle.


Subject(s)
Arsenicals/pharmacology , Deoxyglucose/metabolism , Ethers, Cyclic/pharmacology , Insulin Resistance , Muscle, Skeletal/drug effects , Vanadates/pharmacology , Adult , Animals , Biological Transport/drug effects , Humans , Male , Muscle, Skeletal/metabolism , Okadaic Acid , Phosphoprotein Phosphatases/antagonists & inhibitors , Rats , Rats, Sprague-Dawley
11.
Diabetes ; 44(6): 695-8, 1995 Jun.
Article in English | MEDLINE | ID: mdl-7789635

ABSTRACT

Insulin and muscle contraction stimulate glucose transport into muscle cells by separate signaling pathways, and hypoxia has been shown to operate via the contraction signaling pathway. To elucidate the mechanism of insulin resistance in human skeletal muscle, strips of rectus abdominis muscle from lean (body mass index [BMI] < 25), obese (BMI > 30), and obese non-insulin-dependent diabetes mellitus (NIDDM) (BMI > 30) patients were incubated under basal and insulin-, hypoxia-, and hypoxia + insulin-stimulated conditions. Insulin significantly stimulated 2-deoxyglucose transport approximately twofold in muscle from lean (P < 0.05) patients, but not in muscle from obese or obese NIDDM patients. Furthermore, maximally insulin-stimulated transport rates in muscle from obese and diabetic patients were significantly lower than rates in muscle from lean patients (P < 0.05). Hypoxia significantly stimulated glucose transport in muscle from lean and obese patients. There were no significant differences in hypoxia-stimulated glucose transport rates among lean, obese, and obese NIDDM groups. Hypoxia + insulin significantly stimulated glucose transport in lean, obese, and diabetic muscle. The results of the present study suggest that the glucose transport effector system is intact in diabetic human muscle when stimulated by hypoxia.


Subject(s)
Glucose/metabolism , Hypoxia/metabolism , Insulin Resistance , Muscle, Skeletal/metabolism , Adult , Biological Transport , Deoxyglucose/metabolism , Diabetes Mellitus/metabolism , Diabetes Mellitus, Type 2/metabolism , Humans , Insulin/metabolism , Insulin/pharmacology , Obesity/metabolism
12.
Diabetes ; 36(5): 620-5, 1987 May.
Article in English | MEDLINE | ID: mdl-3032715

ABSTRACT

We have determined glucose transport, insulin binding, and insulin-receptor kinase activity in adipose tissue from morbidly obese patients with and without non-insulin-dependent diabetes mellitus (NIDDM). The insulin sensitivity and responsiveness of glucose transport in freshly isolated adipocytes were significantly reduced in NIDDM subjects compared with nondiabetics. This was due in part to decreased insulin binding in adipocytes. Reduced specific 125I-labeled insulin binding was also observed in crude detergent extracts and partially purified insulin receptors from adipose tissue. In addition, the basal and insulin-stimulated tyrosine-specific protein kinase activity per milligram of protein was significantly decreased in NIDDM patients compared with nondiabetics. The differences between maximally insulin-stimulated and basal kinase activities expressed by insulin-binding activity were also significantly reduced in NIDDM subjects. We conclude that insulin resistance in morbidly obese patients with NIDDM is due to both insulin-binding and postbinding defects. One of the postbinding defects in NIDDM appears to be impaired insulin-receptor kinase activity of fat tissue.


Subject(s)
Adipose Tissue/metabolism , Diabetes Mellitus, Type 2/metabolism , Insulin Resistance , Obesity/metabolism , Protein-Tyrosine Kinases/metabolism , Adipose Tissue/drug effects , Adult , Biological Transport/drug effects , Diabetes Mellitus, Type 2/complications , Female , Glucose/metabolism , Humans , Insulin/metabolism , Insulin/pharmacology , Male , Obesity/complications , Receptor, Insulin/metabolism
13.
Diabetes ; 40(4): 472-7, 1991 Apr.
Article in English | MEDLINE | ID: mdl-2010047

ABSTRACT

We investigated the mechanism of peripheral insulin resistance in the adipose tissue of obese and non-insulin-dependent diabetes mellitus (NIDDM) patients at the level of the glucose-transport effector system. Freshly isolated adipocytes from obese nondiabetic and obese NIDDM subjects had decreased insulin sensitivity and responsiveness for glucose-transport stimulation compared with control subjects, with more pronounced changes associated with obese NIDDM patients. The relative abundance of muscle/fat glucose-transporter isoform in the three groups of subjects was determined by Western-blot analysis of detergent-soluble adipose tissue extracts with monoclonal antibody 1F8. Obesity per se had no effect on adipose tissue muscle/fat glucose-transporter isoform (3150 +/- 660 vs. 4495 +/- 410 counts/min [cpm]/mg protein). Furthermore, decreased levels of muscle/fat isoform in adipose tissue of NIDDM patients were also reflected in isolated adipocytes. Our results demonstrate that insulin resistance in isolated adipocytes of NIDDM patients could at least partly be due to a significant depletion of adipose tissue muscle/fat glucose-transporter isoform.


Subject(s)
Adipose Tissue/metabolism , Diabetes Mellitus, Type 2/metabolism , Diabetes Mellitus/metabolism , Monosaccharide Transport Proteins/metabolism , Muscles/metabolism , Obesity, Morbid/metabolism , Obesity , Adipose Tissue/drug effects , Adult , Cell Membrane/metabolism , Cells, Cultured , Female , Humans , Insulin/pharmacology , Male , Molecular Weight , Monosaccharide Transport Proteins/isolation & purification , Reference Values
14.
Diabetes ; 39(9): 1028-32, 1990 Sep.
Article in English | MEDLINE | ID: mdl-2166697

ABSTRACT

Based on the observation that insulinlike growth factor I (IGF-I) can stimulate glucose utilization in nondiabetic subjects and that the action of the IGF-I receptor is normal in the skeletal muscle of patients with non-insulin-dependent diabetes mellitus (NIDDM), it seems possible that IGF-I might provide an effective acute treatment for the hyperglycemia of NIDDM. Using our recently developed in vitro human muscle preparation, we investigated the hypothesis that IGF-I might be an effective alternative to insulin in stimulating glucose transport in diabetic muscle. Abdominal muscle samples from nonobese nondiabetic, obese nondiabetic, and obese NIDDM patients were obtained during elective abdominal surgery. Plasma levels of IGF-I in diabetic patients were lower than those in either of the nondiabetic groups. Binding studies with wheat-germ-agglutinin-chromatography-purified receptors demonstrated the presence of IGF-I receptors in human muscle, with IGF-I binding being approximately 24% that of insulin. There was no change in IGF-I binding in muscle from obese or diabetic subjects, and the structural characteristics of the IGF-I receptor were not altered, as determined by electrophoretic mobility. IGF-I stimulated glucose transport approximately twofold in incubated muscle from control subjects, but there was no IGF-I stimulation of transport in muscle from obese subjects with or without NIDDM. These results confirm a previous report that human muscle contains receptors for IGF-I and demonstrate for the first time that IGF-I can stimulate glucose transport in human muscle. However, muscle from obese subjects with or without NIDDM is resistant to the action of IGF-I.


Subject(s)
Diabetes Mellitus, Type 2/metabolism , Diabetes Mellitus/metabolism , Glucose/metabolism , Insulin-Like Growth Factor I/physiology , Muscles/metabolism , Obesity/metabolism , Somatomedins/physiology , Adult , Biological Transport , Deoxyglucose/pharmacokinetics , Female , Humans , In Vitro Techniques , Male , Receptors, Cell Surface/metabolism , Receptors, Cell Surface/physiology , Receptors, Somatomedin
15.
Diabetes ; 38(10): 1217-25, 1989 Oct.
Article in English | MEDLINE | ID: mdl-2551760

ABSTRACT

We demonstrate the presence of specific insulinlike growth factor I (IGF-I) receptors in human adipocytes. Competition studies with 125I-labeled IGF-I and unlabeled IGF-I, IGF-II, and insulin showed the specificity of 125I-IGF-I binding to the IGF-I receptors in adipocytes, membranes, and partially purified detergent-solubilized extracts. The monoclonal antibody to the IGF-I receptor (alpha-IR3) inhibits 125I-IGF-I binding and immunoprecipitates the IGF-I receptor. In addition, the alpha-subunit of IGF-I receptor is approximately 10,000 Mr larger than the alpha-subunit of insulin receptor, and IGF-I stimulates phosphorylation of the beta-subunit of the IGF-I receptor. IGF-I stimulates basal glucose transport in human adipocytes, but the concentrations of IGF-I required for half-maximal and maximal stimulation of glucose transport are 800- and 1000-fold greater than that of insulin. The possibility of IGF-I stimulating glucose transport by interacting predominantly with insulin receptors is suggested by data showing that 1) IGF-I competes with insulin-binding sites, 2) there is a lack of an additive effect with IGF-I and insulin in stimulating glucose transport, 3) alpha-IR3, which specifically inhibits IGF-I binding, does not inhibit IGF-I or insulin-stimulated glucose transport, 4) insulin-receptor antibody MA-10 inhibits IGF-I and insulin-stimulated glucose transport, and 5) IGF-I stimulates insulin-receptor autophosphorylation, although its effect is markedly decreased compared with insulin. In summary, human adipocytes possess specific IGF-I receptors. However, IGF-I stimulates glucose transport predominantly by interacting with the insulin receptor.


Subject(s)
Adipose Tissue/metabolism , Glucose/metabolism , Insulin-Like Growth Factor I/pharmacology , Receptors, Cell Surface/physiology , Somatomedins/pharmacology , Adipose Tissue/drug effects , Binding, Competitive , Cell Membrane/metabolism , Cells, Cultured , Humans , Insulin/pharmacology , Insulin-Like Growth Factor I/metabolism , Kinetics , Molecular Weight , Phosphorylation , Protein-Tyrosine Kinases/metabolism , Receptor, Insulin/isolation & purification , Receptor, Insulin/metabolism , Receptors, Somatomedin , Recombinant Proteins/metabolism , Recombinant Proteins/pharmacology
16.
Diabetes Care ; 17(5): 372-5, 1994 May.
Article in English | MEDLINE | ID: mdl-8062602

ABSTRACT

OBJECTIVE: To determine if weight loss may prevent conversion of impaired glucose tolerance (IGT) to diabetes, because weight loss reduces insulin resistance. The prevalence of IGT in the U.S. population is estimated at 11.2%, more than twice that of diabetes. Furthermore, because an oral glucose tolerance test is needed for its detection, most of these patients are undiagnosed. Screening for IGT would be meaningful if progression to diabetes could be delayed or prevented. RESEARCH DESIGN AND METHODS: For an average of 5.8 years (range 2-10 years), 136 individuals with IGT and clinically severe obesity (> 45 kg excess body weight) were followed. The experimental group included 109 patients with IGT who underwent bariatric surgery for weight loss. The control group was made up of 27 subjects with IGT who did not have bariatric surgery. The criteria of the World Health Organization was used to detect IGT and diabetes in this population. The main outcome measure of this nonrandomized control trial is the incidence density, or number of events (development of diabetes) divided by the time of exposure to risk. RESULTS: Of the 27 subjects in the control group, 6 developed diabetes during an average of 4.8 +/- 2.5 years of postdiagnosis follow-up, yielding a rate of conversion to diabetes of 4.72 cases per 100 person-years. The 109 individuals of the experimental group were followed for an average of 6.2 +/- 2.5 years postbariatric surgery. Based on the 95% confidence interval of the comparison group, we would expect to find that between 22 and 36 subjects in the experimental group developed diabetes over the follow-up period. Only 1 of the 109 experimental-group patients developed diabetes, resulting in a conversion rate of the experimental group of only 0.15 cases per 100 person-years, which is significantly lower (P < 0.0001) than the control group. CONCLUSIONS: Weight loss in patients with clinically severe obesity prevents the progression of IGT to diabetes by > 30-fold.


Subject(s)
Diabetes Mellitus, Type 2/prevention & control , Glucose Intolerance/physiopathology , Obesity/physiopathology , Weight Loss , Adult , Diabetes Mellitus, Type 2/epidemiology , Female , Glucose Intolerance/complications , Glucose Intolerance/epidemiology , Humans , Incidence , Longitudinal Studies , Male , Obesity/complications , Obesity/surgery , Risk Factors , Stomach/surgery , United States/epidemiology
17.
Am J Clin Nutr ; 55(2 Suppl): 582S-585S, 1992 02.
Article in English | MEDLINE | ID: mdl-1733132

ABSTRACT

Since 1980 we have performed the identical Greenville gastric bypass (GGB) procedure on 479 morbidly obese patients with an acceptable morbidity and a mortality rate of 1.2%. The weight loss in the series was well maintained over the follow-up period of 10 y. The GGB can control non-insulin-dependent diabetes mellitus (NIDDM) in most patients. The group of 479 patients included 101 (21%) with NIDDM and another 62 (13%) who were glucose impaired. Of these 163 individuals, 141 reverted to normal and only 22 (5%) remained with inadequate control of their carbohydrate metabolism. Those patients who were older or whose diabetes was of longer duration were less likely to revert to normal values. The gastric bypass operation is an effective approach for the treatment of morbid obesity. Along with its control of weight, the operation also controls the hyperglycemia, hyperinsulinemia, and insulin resistance of the majority of patients with either glucose impairment or frank NIDDM.


Subject(s)
Diabetes Mellitus, Type 2/surgery , Diabetes Mellitus/surgery , Obesity , Adult , Blood Glucose/metabolism , Diabetes Complications , Diabetes Mellitus, Type 2/complications , Follow-Up Studies , Gastric Bypass , Humans , Insulin/metabolism , Middle Aged , Obesity, Morbid/complications , Obesity, Morbid/surgery , Weight Loss
18.
Am J Surg Pathol ; 10(8): 539-45, 1986 Aug.
Article in English | MEDLINE | ID: mdl-3526931

ABSTRACT

Two examples of localized primary amyloid tumor of the breast are presented, including one patient with metachronous bilateral lesions. Our findings and review of the literature indicate that this rare lesion occurs predominantly in elderly females and can be mammographically and clinically confused with carcinoma. Fine-needle aspiration biopsy can be a useful procedure to make a preliminary diagnosis. Congo red staining with prior potassium permanganate incubation confirmed the AL type of amyloid in our two cases; this might be the predominant type in the localized form involving the breast. Immunofluorescence studies demonstrated IgA, with kappa and lambda light-chain deposition within the amyloid foci in one case, and intracytoplasmic IgG with both light chains within plasma cells and amyloid deposits of the second case. Ultrastructural examination of one of the cases showed characteristic findings of straight, nonbranching fibrils of 4-9 nm, diagnostic of amyloid. From our findings and a review of the literature, we conclude that amyloid tumors of the breast can occur in three separate settings: secondary amyloidosis, systemic or multiple myeloma associated amyloidosis, and as a localized primary type having a benign course.


Subject(s)
Amyloidosis/pathology , Breast Diseases/pathology , Age Factors , Aged , Amyloid/analysis , Amyloidosis/immunology , Biopsy, Needle , Breast/analysis , Breast Neoplasms/immunology , Female , Histocytochemistry , Humans , Immunoglobulin A/analysis , Immunoglobulin G/analysis
19.
Obes Surg ; 7(1): 16-8, 1997 Feb.
Article in English | MEDLINE | ID: mdl-9730531

ABSTRACT

BACKGROUND: Morbid obesity is a serious disease that afflicts over five million Americans, threatening their health with such co-morbidities as diabetes, arthritis, pulmonary failure and stroke. Surgery is the only effective therapy, providing long-term control of weight, diabetes, pulmonary failure, and hypertension for as long as 14 years. Because the operation presents a major expense, this study examined whether X-ray examination of the gut could be omitted safely as a cost-saving measure. METHODS: The records of 814 consecutive morbidly obese patients who underwent gastric bypass were reviewed to determine: (1) whether these individuals had undergone an upper gastro-intestinal (GI) series, and (2) if these studies influenced therapy or caused cancellation or postponement of surgery. RESULTS: Of the 814 patients, 657 (80.7%) underwent a preoperative GI radiography. Of these examinations, 393 (59.8%) were normal, with the following abnormalities in the remaining 264: hiatal hernia, 164; esophageal reflux, 39; Schatzki's ring, 18; small bowel diverticula, four; renal stones, four; malrotation, three; gall stones, two; pyloric ulcer, one; possible pelvic mass, one; calcified leiomyoma, one; and dysphagial lusoria, one. None of these findings resulted in cancellation or a delay in surgery. CONCLUSIONS: The upper GI series can be safely omitted from the routine preoperative evaluation of patients undergoing gastric bypass. At a cost of $741.00 per examination, this change represents significant potential savings. Similar evaluations of other routine preoperative tests may well provide a better basis for the evaluation of these complex patients.


Subject(s)
Diagnostic Tests, Routine/statistics & numerical data , Digestive System/diagnostic imaging , Gastric Bypass , Preoperative Care/statistics & numerical data , Adult , Cost Savings , Diagnostic Tests, Routine/economics , Gastric Bypass/economics , Humans , Obesity, Morbid/diagnostic imaging , Preoperative Care/economics , Radiography
20.
Surgery ; 80(4): 480-7, 1976 Oct.
Article in English | MEDLINE | ID: mdl-135365

ABSTRACT

A series of 75 patients, with an average age of 65 years, underwent the following extra-anatomic bypasses involving the crossover femorofemoral principle: femorofemoral (F-F), 54 patients; aortofemorofemoral (A-F-F), 12 patients; common iliac-femorofemoral (CI-F-F), six patients; and axillofemorofemoral (Ax-F-F), three patients. Fifty eight of the 75 patients (77 percent) initially presented with rest pain or gangrene. The operative mortality rate in this high-risk group of patients was 4 percent. Analysis by the life-table method showed the graft patency rate to be 91.1 percent at one year and 87.4 percent at 18 months. There have been no graft failures or deaths in the series of 20 patients followed longer than 18 months. Two amputations followed graft failures and nine of the remaining 11 amputations were done in patients with patent grafts during the same period of hospitalization, reflecting the severity of their gangrene upon admission. High-risk patients who are not suitable for crossover F-F grafts without an inflow procedure may be suitable for a CI-F-F or A-F-F bypass before being considered for an Ax-F-F bypass.


Subject(s)
Aortic Diseases/surgery , Arterial Occlusive Diseases/surgery , Blood Vessel Prosthesis/methods , Iliac Artery/surgery , Adult , Aged , Amputation, Surgical , Angiography , Aorta, Abdominal/surgery , Diabetic Angiopathies/surgery , Female , Femoral Artery/surgery , Gangrene/surgery , Humans , Leg/blood supply , Male , Middle Aged , Polyethylene Terephthalates
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