Effect of Ramadan fasting on fuel oxidation during exercise in trained male rugby players

PURPOSE

The aim of this study was to assess the effect of Ramadan fasting on substrate oxidation in trained athletes during moderate-intensity exercise.

METHODS

Nine trained men (age: 19+/-2 yr, Height: 1.78+/-0.74 m) were tested on three occasions: during a control period immediately before Ramadan (C), at the end of the first week (Beg-R), and during the fourth week of Ramadan (End-R). On each occasion, they performed submaximal cycle ergometer exercise, with work-rates that were increased progressively (loadings corresponding to 20, 30, 40, 50, 60% of Wmax). Steady-state substrate oxidation was evaluated by indirect calorimetry.

RESULTS

Participants showed significant decreases in body mass and body fat at the end of Ramadan, relative to initial control values (P<0.001). The daily food intake was also reduced during Ramadan (P<0.01). Haemoglobin concentrations and hematocrit were significantly higher at the end-Ramadan, both at rest (P<0.001 and P<0.0001 respectively) and after exercise, (P<0.05 and P<0.01 respectively) compared to control measurements made before Ramadan. At the end of Ramadan, our subjects had increased their fat utilization during exercise. The cross-over was observed at a higher intensity at the End-R (35% vs. 30% of Wmax, P<0.001). For the same power output, the Lipox max was also higher at the End-R, compared to control value (265+/-38 vs. 199.1+/-20 mg/min, P<0.001).

CONCLUSION

Ramadan fasting increases the lipid oxidation of trained athletes during submaximal exercise. The increased fat utilisation may be related to decreases in body mass and body fat content.

Substrate oxidation during exercise: type 2 diabetes is associated with a decrease in lipid oxidation and an earlier shift towards carbohydrate utilization

OBJECTIVES

Exercise is a recommended treatment for type 2 diabetes but the actual pattern of metabolic adaptation to exercise in this disease is poorly known and not taken in account in the protocols used. Metabolic defects involved in the pathways of substrate oxidation were described in type 2 diabetes. We hypothesized that type 2 diabetes, regardless of age, gender, training status and weight, could influence by its own the balance of substrates at exercise.

METHODS

30 sedentary type 2 diabetic subjects and 38 sedentary matched control subjects were recruited. We used exercise calorimetry to determine lipid and carbohydrate oxidation rates. We calculated two parameters quantifying the balance of substrates induced by increasing exercise intensity: the maximal lipid oxidation point (PLipoxMax) and the Crossover point (COP), intensity from which the part of carbohydrate utilization providing energy becomes predominant on lipid oxidation.

RESULTS

Lipid oxidation was lower in the diabetic group, independent of exercise intensity. PLipoxMax and COP were lower in the diabetic group [PLipoxMax=25.3+/-1.4% vs. 36.6+/-1.7% %Wmax (P<0.0001)] - COP =24.2+/-2.2% vs. 38.8+/-1.9% %Wmax (P<0.0001).

CONCLUSIONS

Type 2 diabetes is associated with a decrease in lipid oxidation at exercise and a shift towards a predominance of carbohydrate oxidation for exercise intensities lower than in control subjects. Taking into account these alterations could provide a basis for personalizing training intensity.

Accuracy of continuous subcutaneous glucose monitoring with the GlucoDay in type 1 diabetic patients treated by subcutaneous insulin infusion during exercise of low versus high intensity

AIM

The GlucoDay allows continuous glucose monitoring by subcutaneous microdialysis in sedentary conditions. To validate it when glycaemia may undergo rapid and dramatic changes, we investigated its accuracy during two exercise sessions with markedly different glucose disposal rates.

METHODS

Nine male diabetic patients, aged 32-61, treated by insulin pumps, first underwent a standard maximal exercise-test designed for determining the maximal oxygen consumption and the first ventilatory threshold (Vt1). Then two 30 min steady-state workloads at 15% below and 15% above the Vt1 were performed in random order with the GlucoDay, and measurement of CHO oxidation rates was made by indirect calorimetry.

RESULTS

CHO oxidation during exercise at +15% Vt1 was higher (+943.5 mg/min, ie +45.5%, P<0.01) than during exercise at -15% Vt1 No hypoglycaemia occurred. Due to breakages of 39% of subcutaneous probes, eleven steady-state sessions in 7 subjects allowed to compare 141 paired glucose (sensor vs. venous) determinations. The Clarke error grid situates 92.9% of glucose values within the A zone and 6.4% within the B zone, while only one pair of values (0.7%) falls in the D zone. Venous glucose tended to decrease more rapidly than sensor glucose during exercise. Bland-Altman plots evidence for a few cases of underestimation of venous glucose at high intensity.

CONCLUSIONS

This study showed satisfactory accuracy of the GlucoDay during exercise. A slight lag time in sensor values likely explains a few discrepancies that do not appear as clinically meaningful. Reduction of probe fragility and confirmed sensor accuracy in hypoglycaemia would further support applicability of GlucoDay at exercise.

Lower ability to oxidize lipids in adult patients with growth hormone (GH) deficiency: reversal under GH treatment

BACKGROUND

The aim of the study was to characterize lipid oxidation at exercise in adults with growth hormone deficiency (GHD) and to evaluate the effect of 6 and 12 months of GH replacement therapy on substrate carbohydrate (CHO) and lipid utilization at exercise.

PATIENTS AND MEASUREMENTS

Twenty-five patients with GHD and 40 matched controls participated in the study. Ten of the 25 GH-deficient patients were treated with recombinant GH for 12 months. Anthropometric measurements and exercise calorimetry were performed before and after treatment. Maximal fat oxidation and the crossover point [that is the percentage of the theoretical maximal power (Wmax th) where CHO become the predominant fuel used for oxidation] were determined.

RESULTS AND CONCLUSION

The GH-deficient patients exhibited a highly significant shift in the balance of substrate oxidation during exercise, towards a decrease in fat oxidation, and a shift towards lower intensities of the crossover (52 +/- 5.5%vs. 72.6 +/- 6.6% of Wmax th, P < 0.03) and maximal fat oxidation (131.04 +/- 14 vs. 234.4 +/- 30.1 mg/min, P < 0.03) in the GHD and control groups, respectively. However, GH treatment at 6 and 12 months partially reversed this defect, resulting in an increase (+83%, P < 0.001) in the maximal ability to oxidize fat during exercise. These findings are consistent with the hypothesis that a lack of GH reduces the ability to oxidize lipids during exercise and that GH treatment restores this muscular metabolic property.

Influence of Temperature, Inoculation Interval, and Dosage on Biofumigation with Muscodor albus to Control Postharvest Gray Mold on Grapes

Control of postharvest gray mold, caused by Botrytis cinerea, on Thompson Seedless grape by biofumigation with a rye grain formulation of Muscodor albus, a fungus that produces volatiles lethal to many microorganisms, was evaluated. The influences of temperature, biofumigant dosage, and interval between inoculation and treatment on disease incidence and severity on detached single berries were assessed. When biofumigation began within 24 h after inoculation, higher M. albus dosages (≥50 g of the M. albus grain formulation per kilogram of grapes at 20°C or 100 g/kg at 5°C) stopped infections and control persisted after M. albus removal. Biofumigation was more effective at 20 than 5°C. Among inoculated clusters inside clamshell boxes incubated for 7 days at 15°C, gray mold incidence was reduced from 20.2% among untreated grape fruit to less than 1%, when ≥5 g of the formulation per kilogram of grapes was added. Among grape berries commercially packaged in ventilated polyethylene cluster bags incubated for 7 days at 15°C, gray mold incidence was 40.5% among untreated fruit and 11.1 or 6.7% when the formulation at 5 or 20 g/kg, respectively, had been added. In the same packaging, among grape berries incubated for 28 days at 0.5°C, gray mold incidence was 42.8% among untreated fruit and 4.8 or 4.0% when the formulation at 5 or 10 g/kg, respectively, had been added. Lower dosages (≤20 g/kg) suppressed disease development while M. albus was present; however, after their removal, B. cinerea resumed growth and gray mold incidence increased. Placement of M. albus inside grape packages significantly controlled gray mold and may be a feasible approach to manage postharvest decay of table grape.

Effect of beta-dystroglycan processing on utrophin/Dp116 anchorage in normal and mdx mouse Schwann cell membrane

In the peripheral nervous system, utrophin and the short dystrophin isoform (Dp116) are co-localized at the outermost layer of the myelin sheath of nerve fibers; together with the dystroglycan complex. Dp116 is associated with multiple glycoproteins, i.e. sarcoglycans, and alpha- and beta-dystroglycan, which anchor the cytoplasmic protein subcomplex to the extracellular basal lamina. In peripheral nerve, matrix metalloproteinase activity disrupts the dystroglycan complex by cleaving the extracellular domain of beta-dystroglycan. Metalloproteinase creates a 30 kDa fragment of beta-dystroglycan, leading to a disruption of the link between the extracellular matrix and the cell membrane. Here we asked if the processing of the beta-dystroglycan could influence the anchorage of Dp116 and/or utrophin in normal and mdx Schwann cell membrane. We showed that metalloproteinase-9 was more activated in mdx nerve than in wild-type ones. This activation leads to an accumulation of the 30 kDa beta-dystroglycan isoform and has an impact on the anchorage of Dp116 and utrophin isoforms in mdx Schwann cells membrane. Our results showed that Dp116 had greater affinity to the full length form of beta-dystroglycan than the 30 kDa form. Moreover, we showed for the first time that the short isoform of utrophin (Up71) was over-expressed in mdx Schwann cells compared with wild-type. In addition, this utrophin isoform (Up71) seems to have greater affinity to the 30 kDa beta-dystroglycan which could explain the increased stabilization of this 30 kDa form at the membrane compartment. Our results highlight the potential participation of the short utrophin isoform and the cleaved form of beta-dystroglycan in mdx Schwann cell membrane architecture. We proposed that these two proteins could be implicated in Schwann cell proliferation in response to a microenvironment stress such as mediated by accumulating macrophages in mdx mouse muscle inflammation sites.

Comparison of the type of substrate oxidation during exercise between pre and post pubertal markedly obese boys

The aim of this study was to investigate, in markedly obese children, the effect of puberty on substrate oxidation during an acute bout of exercise. Two groups of markedly obese boys (7 pre pubertal, 8 post pubertal, matched for adiposity) performed an exercise-test designed for measuring carbohydrate and fat oxidation with indirect calorimetry, and consisting of five six-minute steady-state workloads at 20, 30, 40, 50, and 60 % of the theoretical maximal aerobic power. Fat oxidation (mg . min (-1)) is correlated to fat free mass (FFM) (r = 0.7, p = 0.02). When expressed in crude flow rate units, fat oxidation is slightly higher in PostP than PreP children (p < 0.05). However, when expressed per unit of FFM or as a percentage of total fuel oxidation, fat oxidation is lower in PostP than PreP children (p < 0.05). Multivariable analysis shows that the influence of age on the ability to oxidize fat at exercise is explained by the pubertal increase in FFM. In markedly obese children during puberty, the ability of each kg of FFM to oxidize fat at exercise decreases (- 28% at 20%Wmax th), but the pubertal increase in FFM overcomes this effect, resulting in an increase in whole body ability to oxidize fat at exercise (+ 17,3% at 20%Wmax th).

The use of dual-energy X-ray absorptiometry to estimate the dissected composition of lamb carcasses

A total of 140 male and female Dorset and Suffolk lambs were slaughtered according to four live weight classes (36-39kg, 41-44kg, 46-49kg and 51-54kg). Total tissue, fat and lean masses, and bone mineral content measured by dual-energy X-ray absorptiometry (DXA) were used to predict dissected tissue weights. The DXA total weights accurately predict half-carcasses and primal cuts weights (shoulder, leg, loin and flank) (R(2)>0.99, CVe<1.3%). The prediction of the half-carcass dissected fat percentage is weaker (R(2)=0.77, CVe=10.4%). Fatness prediction accuracy is equivalent for the shoulder, leg and loin (R(2) between 0.68 and 0.78, CVe between 10% and 13%). The R(2) obtained when predicting dissected lean content from DXA variables is 0.93 for the half-carcass and higher than 0.83 for all cuts other than flank (CVe are between 3.5% and 6.5%, except for the flank, which is 9.1%). The prediction of bone weight using the bone mineral content is not very accurate for the half-carcass, shoulder and leg (R(2): 0.48, 0.47 and 0.43; CVe: 10.2%, 12.0% and 11.6%, respectively). The situation improves, however, for the loin (R(2)=0.70, CVe=10.7%). In conclusion, DXA is an effective technology for predicting total weight and the amount of lean and fat in lamb carcasses and their primal cuts.

Impact of high- and low-intensity targeted exercise training on the type of substrate utilization in obese boys submitted to a hypocaloric diet

BACKGROUND

We assessed the effect of two programs combining a hypocaloric diet with low-intensity (LI) or high-intensity (HI) exercise training, during two months, on substrate utilization at exercise in obese children.

METHODS

Fifteen obese boys participated in a combined program of exercise and caloric restriction-induced weight loss (diet starting two weeks before the training program). The maximal fat oxidation point (Lipox max) was determined to individualize exercise training. Training consisted of cycling at either LI (Lipox max) for seven children or HI (Lipoxmax+40% Lipox max) for eight children.

RESULTS

All children exhibited a decrease in weight (LI: -5.2 kg +/- 0.7 (P<0.01), HI: -7 kg +/- 0.7 (P<0.01)). While in the LI group, both fat and CHO oxidation were unchanged after training, HI group oxidize less fat and more CHO after training when exercising at 20% and 30% Wmax th (P = 0.02).

DISCUSSION

While a LI exercise training program maintains (but does not improve) the ability to oxidize fat at exercise, HI training actually shifts towards CHO the balance of substrate oxidation during exercise. Thus, a low intensity training protocol seems to counteract to some extent the decline in lipid oxidation at exercise that occurs after a hypocaloric diet, and is thus likely to be synergistic to diet in the weight lowering strategy.

Substrate oxidation during exercise: impact of time interval from the last meal in obese women

OBJECTIVE

To investigate whether time interval between meal and exercise alters the balance of substrate oxidation during an exercise bout.

HYPOTHESIS

Exercise performed 3-h after meal induces a higher rate of lipid oxidation than when performed only 1-h after meal.

RESEARCH METHODS AND PROCEDURES

Eight overweight and obese postmenopausal women (age: 57.4+/-2.4 y; BMI: 31.8+/-2.1 kg m(-2); %FAT: 42.7+/-1.2%, mean+/-s.e.m.) performed two sessions of exercise training at an intensity corresponding to their ' crossover' point of substrate oxidation (COP(ox)). One session was held 1 h after a standardized meal and the other, 3 h after an identical meal on another day. Substrate oxidation was evaluated by indirect calorimetry. Hormonal responses were investigated during exercise.

RESULTS

Respiratory exchange ratio values were lower in the 3-h condition, showing higher lipid oxidation during exercise (average difference+38.9+/-2.7 mg min(-1); P<0.001), while mean energy expenditure did not differ. Basal heart rate was reduced in the 3 h compared with the 1-h condition (78+/-5 vs 87+/-5 bpm; P<0.05). Glycemia, lactatemia and insulinemia were reduced when exercise was performed 3 h after meal (P<0.05).

DISCUSSION

When exercise is performed 3 h after meal at an intensity corresponding to the COP(ox), metabolic and hormonal responses are similar to those targeted during the submaximal exercise test performed at fast that we previously proposed to individualize exercise training in the obese.

Ubiquitin targeting of rat muscle proteins during short periods of unloading

AIM

The ubiquitin-proteasome system is known to be involved in many situations leading to skeletal muscle atrophy. However, the cellular mechanisms triggering the atrophic process initiation are still poorly understood. For short periods of rat hindlimb unloading, we assessed the specific ubiquitin targeting of sarcoplasmic or myofibrillar proteins in slow and fast rat muscle types.

METHODS

Adult Sprague Dawley rats were randomly assigned to three groups: control, hindlimb-unloaded for 4 days (HU4) and hindlimb-unloaded for 8 days (HU8). In fractionated extracts from soleus (SOL) and Extensor Digitorum Longus (EDL) muscles, the relative contents of free and conjugated ubiquitin were quantified by immunoblotting.

RESULTS

Hindlimb unloading of short durations resulted in a preferential atrophy of slow-twitch fibres and bound ubiquitin levels were increased by 37 and 68% in the soleus myofibrillar fraction after respectively 4 and 8 days. The ubiquitin conjugation was shown to principally affect the high molecular weight proteins. Free and conjugated ubiquitin levels remained unchanged in sarcoplasmic fraction from SOL muscle after 8 days HU. For the fast muscle (EDL), ubiquitin contents were approximately twofold lower in control conditions, and did not significantly change during the hindlimb unloading periods considered.

CONCLUSION

The postural SOL muscle was shown to contain higher constitutive sarcoplasmic ubiquitin levels than the phasic EDL. The high response to unloading of the slow twitch fibres rich SOL muscle was accompanied by a specific conjugation of its myofibrillar proteins that may participate in the initiation of skeletal muscle remodelling consequent to disuse.

Is hemoglobin desaturation related to blood viscosity in athletes during exercise?

Several studies have suggested that athletes with low hemoglobin saturation during exercise may experience impaired pulmonary blood gas exchange during maximal exercise. Blood viscosity may be implicated in exercise-induced pulmonary hemorrhage in race horses. We hypothesized that blood rheology may contribute to impaired gas exchange and reduced hemoglobin saturation during exercise in humans. A group of 20 highly trained endurance athletes participated in this study, 9 with low hemoglobin saturation during exercise (Low-SpO (2) group) and 11 with normal hemoglobin saturation (High-SpO (2) group). All subjects performed a progressive exercise test conducted to V.O (2max). Venous blood was sampled at rest, 50 % V.O (2max) and maximal exercise. Blood viscosity (etab) was measured at very high shear rate (1000 s (-1)) and 37 degrees C with a falling ball viscometer. The erythrocyte rigidity coefficient, "Tk", was calculated using the Dintenfass equation. At rest, no significant difference in etab was observed between the two groups (3.00 +/- 0.08 mPa . s vs. 3.01 +/- 0.04 mPa . s for the Low-SpO (2) and High-SpO (2) group, respectively). At 50 % V.O (2max) and maximal exercise, etab was higher in Low-SpO (2) (p < 0.01). Tk decreased in High-SpO (2) (p < 0.01) but remained unchanged in the other group during testing. The greater increase in etab in the Low-SpO (2) group during exercise may therefore have been due to the lack of reduction in Tk. As suggested by previous studies, the greater increase in blood viscosity in athletes with low hemoglobin saturation may lead to vascular shear stress. Whether this could impair the blood gas barrier and result in exercise-induced hypoxemia requires further study.

Blood Rheological Responses to Running and Cycling: A Potential Effect on the Arterial Hypoxemia of Highly Trained Athletes?

To investigate 1) the blood rheological responses to high training volume and 2) the potential effect of these responses on arterial hypoxemia induced during submaximal running and cycling, 10 triathletes performed an incremental cycle test, 20 minutes of running (R), and 20 minutes of cycling (C). All trials were performed at nearly 75 % of VO2max. Hematocrit (H), blood viscosity (etab), plasma viscosity (etapl), index of erythrocyte rigidity (Tk), changes in plasma volume (DeltaPV), pulmonary diffusing capacity (DLco), and arteriolized blood gas (PaO2) were measured before and after each trial. Pulse oxymetry (SpO2) and cardioventilatory data were collected continuously. A significant increase in etab, etapl, and H was noted after R and C with respect to pre-exercise, whereas DeltaPV decreased, with a greater decrease after C. Tk was significantly higher after R than after C. A significantly greater drop in DLco was noted after C compared with R. SpO2 decreased significantly more during R, as did PaO2. We conclude that blood rheological responses are specific to running and cycling. Cycling induced a sharp decrease in plasma volume, which could partially explain the greater DLco alteration. Running was characterized by an increase in Tk, which could be implicated in the severity of the drop in arterial oxygenation observed.

Relationships between maximal muscle oxidative capacity and blood lactate removal after supramaximal exercise and fatigue indexes in humans

The present study investigated whether blood lactate removal after supramaximal exercise and fatigue indexes measured during continuous and intermittent supramaximal exercises are related to the maximal muscle oxidative capacity in humans with different training status. Lactate recovery curves were obtained after a 1-min all-out exercise. A biexponential time function was then used to determine the velocity constant of the slow phase (γ2), which denoted the blood lactate removal ability. Fatigue indexes were calculated during all-out (FIAO) and repeated 10-s cycling sprints (FISprint). Biopsies were taken from the vastus lateralis muscle, and maximal ADP-stimulated mitochondrial respiration ( Vmax) was evaluated in an oxygraph cell on saponin-permeabilized muscle fibers with pyruvate + malate and glutamate + malate as substrates. Significant relationships were found between γ2 and pyruvate + malate Vmax ( r = 0.60, P < 0.05), γ2 and glutamate + malate Vmax ( r = 0.66, P < 0.01), and γ2 and citrate synthase activity ( r = 0.76, P < 0.01). In addition, γ2, glutamate + malate Vmax, and pyruvate + malate Vmax were related to FIAO (γ2 − FIAO: r = 0.85; P < 0.01; glutamate + malate Vmax − FIAO: r = 0.70, P < 0.01; and pyruvate + malate Vmax − FIAO: r = 0.63, P < 0.01) and FISprint (γ2 − FISprint: r = 0.74, P < 0.01; glutamate + malate Vmax − FISprint: r = 0.64, P < 0.01; and pyruvate + malate Vmax − FISprint: r = 0.46, P < 0.01). In conclusion, these results suggested that the maximal muscle oxidative capacity was related to blood lactate removal ability after a 1-min all-out test. Moreover, maximal muscle oxidative capacity and blood lactate removal ability were associated with the delay in the fatigue observed during continuous and intermittent supramaximal exercises in well-trained subjects.

Monocarboxylate transporters, blood lactate removal after supramaximal exercise, and fatigue indexes in humans

The present study investigated whether muscular monocarboxylate transporter (MCT) 1 and 4 contents are related to the blood lactate removal after supramaximal exercise, fatigue indexes measured during different supramaximal exercises, and muscle oxidative parameters in 15 humans with different training status. Lactate recovery curves were obtained after a 1-min all-out exercise. A biexponential time function was then used to determine the velocity constant of the slow phase (gamma(2)), which denoted the blood lactate removal ability. Fatigue indexes were calculated during 1-min all-out (FI(AO)) and repeated 10-s (FI(Sprint)) cycling sprints. Biopsies were taken from the vastus lateralis muscle. MCT1 and MCT4 contents were quantified by Western blots, and maximal muscle oxidative capacity (V(max)) was evaluated with pyruvate + malate and glutamate + malate as substrates. The results showed that the blood lactate removal ability (i.e., gamma(2)) after a 1-min all-out test was significantly related to MCT1 content (r = 0.70, P < 0.01) but not to MCT4 (r = 0.50, P > 0.05). However, greater MCT1 and MCT4 contents were negatively related with a reduction of blood lactate concentration at the end of 1-min all-out exercise (r = -0.56, and r = -0.61, P < 0.05, respectively). Among skeletal muscle oxidative indexes, we only found a relationship between MCT1 and glutamate + malate V(max) (r = 0.63, P < 0.05). Furthermore, MCT1 content, but not MCT4, was inversely related to FI(AO) (r = -0.54, P < 0.05) and FI(Sprint) (r = -0.58, P < 0.05). We concluded that skeletal muscle MCT1 expression was associated with the velocity constant of net blood lactate removal after a 1-min all-out test and with the fatigue indexes. It is proposed that MCT1 expression may be important for blood lactate removal after supramaximal exercise based on the existence of lactate shuttles and, in turn, in favor of a better tolerance to muscle fatigue.

Low intensity endurance exercise targeted for lipid oxidation improves body composition and insulin sensitivity in patients with the metabolic syndrome

BACKGROUND

To investigate the effects of individualized training on the metabolic syndrome.

METHODS

Twenty-eight patients, suffering from the metabolic syndrome were studied before and after 2 months of training and compared to eleven patients who did not follow any training. All the patients were overweight. Training was individualized at the point where fat oxidation was maximal (LIPOX(max)) as determined by calorimetry.

RESULTS

The patients exhibited a significant reduction in body weight (- 2.6 +/- 0.7 kg; P=0.002), fat mass (- 1.55 +/- 0.5 kg; P=0.009), waist (- 3.53 +/- 1.3 cm; P<0.05) and hip (- 2.21 +/- 0.9 cm; P<0.05) circumferences, and improved the ability to oxidize lipids at exercise (crossover point: + 31.7 +/- 5.8 W; P<0.0001; LIPOX(max): + 23.5 +/- 5.6 W; P<0.0001; lipid oxidation: + 68.5 +/- 15.4 mg.min(-1); P=0.0001). No clear improvement in either lipid parameters or fibrinogen were observed. The surrogates of insulin sensitivity evidenced a decrease in insulin resistance: HOMA%S (software): + 72.93 +/- 32.64; p<0.05; HOMA-IR (simplified formula): - 2.42 +/- 1.07; P<0.05; QUICKI: + 0.02 +/- 0.004; P<0.01; SI=40/I: + 3.28 +/- 1.5; P<0.05. Significant correlations were found between changes in body weight and HOMA-IR and between changes in LIPOX(max) and QUICKI.

CONCLUSIONS

Individualized aerobic training improves lipid oxidation, body composition and insulin resistance.

[Total osteotomy for maxillary setback. Indications, technique, results]

PURPOSE

Maxillary skeletal protrusion used to be treated by orthodontic treatment or combined surgical and orthodontic treatment consisting in extraction of two maxillary premolars associated with anterior maxillary osteotomy. Although the anterior occlusal result is quite often good, the esthetic impact is often unsatisfactory. Furthermore, these methods do not correct for the generally associated vertical maxillary excess nor for the first molar class II relation.

MATERIAL AND METHODS

This retrospective study included 11 patients who underwent posterior repositioning of the maxilla between 1986 and 2001. The indication for surgery was based on clinical and cephalometric criteria as exposed. Patient evaluation was based on bony stability and relation between hard and soft tissue changes, and changes in hard and soft tissues cephalometric landmarks assessed prior to surgery, post operatively and six months post operatively.

RESULTS

Results were considered quite good with restoration of a first molar Class I relation, restitution of facial harmony and an esthetic soft tissue profile. Cutaneous movements after surgery, the relation between hard and soft tissue changes and rate of relapse are reported.

DISCUSSION

We compared our series with those reported in the literature emphasizing diagnostic and technical difficulties. This method, which provides good healing as well as the good stability can be recommended for surgical treatment of patients with maxillary protrusion associated with vertical maxillary excess.