Comparison of Intestinal Absorption Rates of Glycine and Glycylglycine in Man and the Effect of Glucose in the Perfusing Fluid

1972 ◽  
Vol 43 (3) ◽  
pp. 443-453 ◽  
Author(s):  
G. C. Cook
Keyword(s):  
Absorption Rate ◽  
Kinetic Curve ◽  
Glucose Absorption ◽  
Double Lumen Tube ◽  
Jejunal Segment ◽  
The Mean ◽  
The Difference ◽  
Mean Glucose ◽  
Effect Of Glucose

1. Using a double-lumen tube perfusion system the rates of glycine, glycylglycine, and glycylglycine and glucose absorption from a 30-cm jejunal segment have been studied in vivo in a group of relatively normal Zambian African subjects. 2. To determine the kinetic curve for glycine absorption, four subjects were given consecutive perfusions of 50, 100 and 150 mm-glycine. 3. Six other subjects had consecutive perfusions of (1) a 100 mm-glycine and (2) a 50 mm-glycylglycine solution. Five of the six had a higher absorption rate of glycine from the glycylglycine solution. When data from a further six similar subjects in another study are included, the mean rate of glycine absorption is significantly greater from the glycylglycine compared with the glycine solution (P < 0·001). 4. A further six subjects were given consecutive perfusions of (1) 50 mm-glycylglycine, (2) 50 mm-glycylglycine and 200 mm-glucose, and (3) 200 mm-glucose. The absorption rate of glycine from glycylglycine was lower in all subjects when glucose was present in the perfusing fluid (P < 0·01). Although the mean glucose absorption rate was lower when glycylglycine was present in the perfusing fluid, the difference was not significant.

Comparison of Absorption Rates of Glucose and Maltose in Man in Vivo

1973 ◽  
Vol 44 (4) ◽  
pp. 425-428 ◽  
Author(s):  
G. C. Cook
Keyword(s):  
Glucose Solution ◽  
Glucose Absorption ◽  
Double Lumen Tube ◽  
Proximal Jejunum ◽  
Perfusion Technique ◽  
Double Lumen ◽  
Lumen Tube ◽  
The Mean ◽  
The Difference

1. Using a double-lumen tube perfusion technique in vivo, the absorption rates of glucose from a glucose (200 mmol l−1) and from a maltose (100 mmol l−1) solution were measured in the proximal jejunum of six Zambian African adults. 2. In all of the subjects the rate of glucose absorption from the maltose solution was greater than that from the glucose solution. The difference between the mean rates was approximately 15% and is significant (P < 0.01).

scholarly journals Increased glycine absorption rate associated with acute bacterial infections in man

1973 ◽  
Vol 29 (3) ◽  
pp. 377-386 ◽  
Author(s):  
G. C. Cook
Keyword(s):  
Bacterial Infections ◽  
Absorption Rate ◽  
Reference Group ◽  
Normal Subjects ◽  
Double Lumen Tube ◽  
Present Observation ◽  
Chronic Infections ◽  
Jejunal Segment ◽  
Acute Bacterial Infections

1. Glycine absorption rate from a 300 mm jejunal segment was determined in vivo in four Zambian African subjects with acute, and four with chronic, respiratory infections. Glycine solutions (100, 150 and 250 mmol/l) were perfused, by means of a double-lumen tube technique. The results were compared with those for four relatively normal Zambian African subjects (‘reference’ group) previously studied. The group with acute-infections had a significantly higher mean absorption rate than the reference or chronic-infection group.2. Glycine absorption results from a 100 mmol/l glycine solution in an additional twenty-four Zambian African subjects have also been analysed. When results for the thirty-six subjects were combined, those with acute bacterial infections had a significantly higher mean absorption rate than the normal subjects or those with chronic infections. For the twenty-one normal subjects there was a significant positive correlation between the individual absorption rates and serum total globulin and γ-globulin concentrations.3. It seems likely that the rapid catabolism of protein associated with infection is counteracted by an increase in amino acid absorption rate. In subjects on a low-protein diet that mechanism would be limited. The deterioration in nutritional status during infections in developing countries could therefore be partly explained by the present observation.

Effect of Intraluminal Concentrations on the Impairment of Glycine Absorption by Glucose in the Human Jejunum

1972 ◽  
Vol 42 (5) ◽  
pp. 525-534 ◽  
Author(s):  
G. C. Cook
Keyword(s):  
Clinical Evidence ◽  
Random Order ◽  
Glucose Absorption ◽  
Double Lumen Tube ◽  
Three Solutions ◽  
Lumen Tube ◽  
Jejunal Absorption ◽  
Jejunal Segment ◽  
The Mean ◽  
African Patients

1. To investigate the effect of different intraluminal concentrations on the mutual inhibitive effect of glycine and glucose on their jejunal absorption rates, eighteen convalescent Zambian African patients who had no clinical evidence of intestinal disease or of malnutrition were given constant intrajejunal infusions with those solutes either together or alone. A double-lumen tube perfusion system was used, and three solutions containing (A) glycine, (B) glycine and glucose, and (C) glucose, all of which were rendered iso-osmotic with sodium chloride, were perfused in random order at 12·0 ml/min. The concentration of glycine in the perfusing fluid was either 10 or 20 mm, and that of glucose either 100, 200 or 280 mm. By reference to polyethylene glycol 4000, the absorption rates of the solutes and water were calculated for a 30 cm jejunal segment. 2. At a glucose concentration of 200 or 280 mm, but not 100 mm, the mean rate of glycine absorption was decreased by approx. 30%. Glucose absorption rates were not significantly altered by glycine. 3. These observations, taken in conjunction with those from a previous investigation, are consistent with the view that there are two mechanisms for the jejunal absorption of glycine in man, one of which is inhibited by glucose at high intraluminal concentration.

scholarly journals Independent jejunal mechanisms for glycine and glycylglycine transfer in man in vivo

1973 ◽  
Vol 30 (1) ◽  
pp. 13-19 ◽  
Author(s):  
G. C. Cook
Keyword(s):  
Absorption Rate ◽  
Clinical Evidence ◽  
Double Lumen Tube ◽  
Transport Mechanisms ◽  
Perfusion System ◽  
Double Lumen ◽  
Lumen Tube ◽  
Jejunal Segment ◽  
Rate Of Absorption

1. Rates of absorption of glycine and glycylglycine from a 300 mm jejunal segment were compared in vivo when those compounds were given alone or together to six Zambian African subjects who had no clinical evidence of malnutrition or of gastro-intestinal disease. Solutions containing (A) glycine (100 mmol/1), (B) glycine (100 mmol/l)+glycylglycine (50 mmol/l), and (C) glycylglycine (50 mmol/l) were infused into the upper jejunum by means of a double-lumen tube perfusion system.2. Rate of absorption of glycine was significantly higher from the glycylglycine solution (C) than from the glycine solution (A). Glycine absorption rate from solution B (glycine+glycylglycine) was very similar to the sum of absorption rates of glycine from solutions A and C in each subject. Luminal disappearance rate of glycylglycine from solutions C and B were very similar; however, the rate was significantly greater than the total glycine absorption rate from solution C and indicates back-diffusion of glycine into the lumen after glycylglycine hydrolysis.3. The results are interpreted as indicating that the transport mechanisms for glycine and glycylglycine in man are partly, and possibly wholly, separate.

scholarly journals Enamel interproximal reduction during treatment with clear aligners: digital planning versus OrthoCAD analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Giuseppina Laganà ◽  
Arianna Malara ◽  
Roberta Lione ◽  
Carlotta Danesi ◽  
Simonetta Meuli ◽  
...  
Keyword(s):  
Treatment Plan ◽  
End Of Treatment ◽  
The Mean ◽  
The Difference ◽  
Dependent Sample ◽  
University Of Rome ◽  
The University ◽  
Enamel Reduction ◽  
Lower Arch

Abstract Background The aim of the study was to compare the amount of interproximal enamel reduction (IPR) provided on ClinCheck software with the amount of IPR carried out by the orthodontist during treatment with clear aligners. Methods 30 subjects (14 males, 16 females; mean age of 24.53 ± 13.41 years) randomly recruited from the Invisalign account of the Department of Orthodontics at the University of Rome “Tor Vergata” from November 2018 to October 2019, were collected according to the following inclusion criteria: mild to moderate dento-alveolar discrepancy (1.5–6.5 mm); Class I canine and molar relationship; full permanent dentition (excluding third molars); both arches treated only using Comprehensive Package by Invisalign system; treatment plan including IPR. Pre- (T0) and post-treatment (T1) digital models (.stl files), created from an iTero scan, were collected from all selected patients. The OrthoCAD digital software was used to measure tooth mesiodistal width in upper and lower arches before (T0) and at the end of treatment (T1) before any refinement. The widest mesio-distal diameter was measured for each tooth excluding molars by “Diagnostic” OrthoCAD tool. The total amount of IPR performed during treatment was obtained comparing the sum of mesio-distal widths of all measured teeth at T0 and T1. Significant T1–T0 differences were tested with dependent sample t-test (P < 0.05). Results In the upper arch, IPR was digitally planned on average for 0.62 mm while in the lower arch was on average for 1.92 mm. As for the amount of enamel actually removed after IPR performing, it was on average 0.62 mm in the maxillary arch. In the mandibular arch, the mean of IPR carried out was 1.93 mm. The difference between planned IPR and performed IPR is described: this difference was on average 0.00 mm in the upper arch and 0.01 in the lower arch. Conclusions The amount of enamel removed in vivo corresponded with the amount of IPR planned by the Orthodontist using ClinCheck software.

In vivo accuracy of image guidance performed using optical tracking and optimized registration

2006 ◽  
Vol 105 (4) ◽  
pp. 561-567 ◽  
Author(s):  
Christopher R. Mascott
Keyword(s):  
Image Guidance ◽  
Optical Tracking ◽  
Guidance System ◽  
Imaging Data ◽  
Mr Images ◽  
Common Error ◽  
Depth Electrodes ◽  
The Mean ◽  
The Difference

Object Image guidance systems involving the use of frameless referencing of surgical space to compile volumetric imaging data sets recently have come into widespread use. Few studies have addressed the true intraoperative surgical accuracy (that is, the application accuracy) of these systems except in a subjective manner. Calculated accuracies given by the systems do not necessarily reflect true intraoperative accuracy. Methods To objectively assess the stereotactic accuracy of a frameless image guidance system using optical spatial referencing, the author analyzed postoperative magnetic resonance (MR) images after placement of depth electrodes for the investigation of epilepsy. Preoperative planning for the treatment of seven patients included implanting skull fiducial screws and obtaining computed tomography/MR fusion images by using ImMerge image fusion software on the StealthStation (Medtronic, Inc.). A total of 42 electrodes were placed. Postoperative volumetric MR images were fused with preoperative study images. The difference between the planned electrode trajectories and targets and the visualized electrodes was measured in stereotactic space. Conclusions The mean distance between the distal electrode contact and the distal end of the planned trajectory for the 42 targets was 3 ± 1.5 mm. The most common error was in depth. The author’s technique did not involve rigid skull fixation of electrodes because they were subsequently tunneled subcutaneously and later removed at the bedside of the patient. Errors in depth were known to be due to traction at the time of tunneling and not due to stereotactic factors. Correcting for depth along the electrode trajectory, the mean accuracy was found to be 2.4 ± 1 mm.

Morphological Changes of The Root Apex In Anterior Teeth With Periapical Periodontitis: An In-Vivo Study

2021 ◽  
Author(s):  
Chen-chen Zhang ◽  
Ya-jing Liu ◽  
Wei-dong Yang ◽  
Qian-nan Zhang ◽  
Ming-zhu Zha ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Root Apex ◽  
Cone Beam ◽  
Reconstruction Technique ◽  
Apical Constriction ◽  
Anterior Teeth ◽  
The Mean ◽  
The Difference ◽  
Periapical Periodontitis

Abstract Introduction: The aim was to analyze the morphological changes of root apex in anterior teeth with periapical periodontitis. Methods: 32 untreated anterior teeth with periapical periodontitis were enrolled, compared with the healthy contralateral teeth. Cone-beam computed tomography was used to measure diameter of the apical constriction. 3D reconstruction technique was used to reconstruct the teeth, analysis the constriction forms, and measure the distances of constriction to apical foramen and anatomical apex respectively. Results: The difference value between buccolingual and mesiodistal diameter was (0.06±0.09) mm in periapical periodontitis and (0.04±0.04) mm in healthy teeth (p<0.05). The mean distances between apical constriction and anatomical apex were (0.97±0.25) mm and (1.59±0.48) mm in periapical periodontitis and healthy teeth. The mean distances of apical constriction to apical foramen were (0.39±0.12) mm and (0.70±0.18) mm in periapical periodontitis and healthy teeth. The most common form of apical construction was flaring (65.6%) in periapical periodontitis. Conclusions: The anterior teeth with periapical periodontitis had shorter distances of apical constriction to anatomical apex and apical foramen, bigger disparities between the diameters of buccolingual and mesiodistal, and higher proportion of flaring apical construction.

scholarly journals The Evaluation of Osseointegration of Dental Implant Surface with Different Size of TiO2Nanotube in Rats

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Young-Ah Yi ◽  
Young-Bum Park ◽  
Hyunmin Choi ◽  
Keun-Woo Lee ◽  
Sun-Jai Kim ◽  
...  
Keyword(s):  
Surface Characteristics ◽  
Sprague Dawley ◽  
Implant Surface ◽  
Removal Torque ◽  
Sprague Dawley Rats ◽  
Dental Implant Surface ◽  
The Mean ◽  
The Difference ◽  
Perfusion Fixation

With the development of nanotechnology, many researches have shown that nanometer-scaled materials especially TiO2nanotube have a positive effect on cellular behavior and surface characteristics of implant, which are considered to be crucial factors in osseointegration. However, it has not yet been verified which nanotube size is effective in osseointegrationin vivo. The aim of this study was to evaluate the effect of implant surface-treated with different size of TiO2nanotubes on osseointegration in rat femur. The customized implants (threaded and nonthreaded type), surface-treated with different diameter of TiO2nanotubes (30 nm, 50 nm, 70 nm, and 100 nm nanotube), were placed on both sides of the femur of 50 male Sprague-Dawley rats (6 weeks old). Rats were sacrificed at 2 and 6 weeks following surgery; then the specimens were collected by perfusion fixation and the osseointegration of implants was evaluated by radiographic and histologic analyses and removal torque value test. The mean of bone area (%) and the mean of removal torque were different in each group, indicating that the difference in TiO2nanotube size may influence new bone formation and osseointegration in rats.

scholarly journals Jejunal absorption rates of glucose, glycine and glycylglycine in Zambian African adults with malnutrition

1974 ◽  
Vol 32 (3) ◽  
pp. 503-513 ◽  
Author(s):  
G. C. Cook
Keyword(s):  
Bacterial Infections ◽  
Absorption Rate ◽  
Clinical Evidence ◽  
Gastrointestinal Disease ◽  
Systemic Infection ◽  
Abdominal Tuberculosis ◽  
Double Lumen Tube ◽  
Albumin Concentration ◽  
Control Subjects

1. Absorption rates of glucose (from a 200 mM solution), glycine (from a 100 mM solution), and glycylglycine (from a 50 mM solution) have been estimated in six Zambian African adults with clinical evidence of malnutrition. A double-lumen tube technique was used to determine absorption rates from a 300 mm section of jejunum in vivo.2. Two of the subjects had ileal tuberculosis and Kaposi's sarcoma respectively. A third probably had abdominal tuberculosis. Three of them had pellagra. Mean serum albumin concentration was 24 (14–43) g/l. Absorption rates have been compared with those in Zambian Africans (control subjects), previously studied, who had no clinical evidence of malnutrition, systemic infection or of gastrointestinal disease.3. Mean glucose, glycine and glycylglycine absorption rates in the malnourished subjects were not significantly different from those in the control subjects. Mean net water absorption rate from the glucose solution was similar in the malnourished subjects and controls; during the glycine and glycylglycine perfusions the mean net absorption rate was, however, significantly lower in the malnourished subjects (P < 0.01 and P < 0.05 respectively); mean net water transfer during the glycine perfusions was towards the jejunal lumen in the malnourished subjects. One subject with pellagra had an abnormal excretion of D-xylose after a 25 g oral load; all other tests were normal.4. It seems probable that malnutrition must be very severe, with jejunal mucosal abnormalities, before absorption rates of glucose, glycine and glycylglycine are significantly altered. The present study does not support the view that subclinical malnutrition is important in producing malabsorption of dietary components in Zambian African subjects. Systemic bacterial infections, and raised serum γ-globulin and immunoglobulin IgG concentrations have previously been associated with an impairment of glucose absorption rate in Zambian African subjects; those factors seem much more likely than subclinical malnutrition to be relevant, in the context of absorption, in the pathogenesis of overt malnutrition.

The effect of two synthetic steroids on plasma glucose concentration and total entry rate of glucose in sheep

1976 ◽  
Vol 87 (2) ◽  
pp. 417-421 ◽  
Author(s):  
Anoma Ranaweera ◽  
E. J. H. Ford
Keyword(s):  
Triamcinolone Acetonide ◽  
Plasma Glucose ◽  
Glucose Concentration ◽  
Intramuscular Injection ◽  
Plasma Glucose Concentration ◽  
Maximum Plasma ◽  
Entry Rate ◽  
The Mean ◽  
The Difference ◽  
Mean Glucose

SummaryPrimed continuous intravenous infusions of tracer amounts of [2·3H]gluscose were used to measure glucose entry rates before and after the administration of triamcinolone acetonide or trienbolone acetate to sheep eating 1200 g/day of chopped hay.The intramuscular injection of triamcinolone acetonide caused hyperglycaemia with a maximum plasma glucose concentration 24 h after the injection. Twenty-four hours after the injection of 0·5 mg/kg of steroid the mean glucose entry rate rose from 1·44 to 2·14 mg/min/kg. The difference between these means is significant (P < 0·02). Twenty-four hours after injecting 0·05 mg/kg of steroid the mean glucose entry rate had risen from 1·34 to 1·86 mg/min/kg. The difference between these means is significant (P < 0·05). The intramuscular injection of trienbolone acetate (0·5 mg/kg) had no effect on plasma glucose concentration or on glucose entry rate.These results are compared with the effect of betamethasone and are discussed in relation to the treatment of ketosis in cattle and sheep.

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