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Biomedical subjects

L Backman

Publications and source records attributed to L Backman.

At least 37 records · Page 2Linked to original sources
PubMed1998

Intraduodenal neuropeptide levels, but not plasma levels, vary in a cyclic fashion with the migrating motor complex.

The neurohormonal control of the migrating motor complex (MMC) is not fully understood. The hypothesis of the present study was that neuropeptide levels might vary with the different phases of the MMC and that a similar variation might be found in the secretions of the gastrointestinal tract. Thus, plasma and intraduodenal concentrations of vasoactive intestinal peptide (VIP), somatostatin (SOM), substance P (SP) and neurokinin A (NKA) were determined by radioimmunoassay every 10 min during two complete MMC cycles in eight male subjects. For comparison, plasma motilin (MOT) concentrations were measured. Plasma concentrations of MOT (mean peak value +/- SEM; 39 +/- 6 pmol L-1), but none of the neuropeptides studied, showed a cyclic variation in plasma with the different phases of the MMC. Peak intraduodenal concentrations of VIP (79 +/- 23 pmol L-1), SOM (2437 +/- 432 pmol L-1) and SP (718 +/- 326 pmol L-1) occurred at or at the time point before the onset of phase III of the MMC. No such correlation was observed for NKA. These results demonstrate that intraduodenal but not plasma concentrations of the neuropeptides VIP, SOM and SP show an association with phase III of the MMC. The biological relevance of this finding is yet unclear, but the results raise the possibility that gut neuropeptides may regulate fasting motility through a luminal release.

Adult↗
PubMed1998

An adjustable vertical banded gastroplasty does not eliminate the risk of staple-line disruption.

BACKGROUND: The two main reasons for reoperation after vertical banded gastroplasty (VBG) in the treatment of obesity are staple-line disruption and stomal stenosis. PATIENTS: Seven morbidly obese patients of mean (+/-SEM) body mass index (BMI) 43.7 +/- 1.9 kg/m2 treated with an adjustable vertical banded gastroplasty (AVBG). RESULTS: No complications of the band system were reported. Weight-loss [BMI at 2 years follow-up 33.9 +/- 6.9 kg/m2 (n = 5)] was equivalent to that seen after VBG with a fixed band. Two of the patients developed staple-line disruption at 18 and 24 months after surgery. CONCLUSION: AVBG allows adjustment of the stoma, but staple-line disruption was common in this small series. It is possible that an excessive filling of the band in order to achieve excess weight loss results in a high pressure in the upper pouch which increases the risk of staple-line disruption.

Adult↗
PubMed1998

Importance of small bowel peptides for the improved glucose metabolism 20 years after jejunoileal bypass for obesity.

BACKGROUND: Obese patients operated with jejunoileal bypass (JIB) have reduced plasma concentrations of insulin and glucose. Gastric inhibitory peptide/glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1) have been found to have a profound incretin effect in humans. The aim of the present study was to examine the long-term effect of JIB on glucose metabolism. METHODS: Four groups (lean, nonoperated obese, obese 9 months after JIB and obese 20 years after JIB) of six females each were given a mixed meal (280 kcal). Plasma samples were obtained every 10 min for 60 min postprandially and were analyzed for glucose, insulin, GIP and GLP-1. RESULTS: A reduction in body mass index (kg/m2) was seen for the two patient groups operated with JIB (12.1, at 9 months post-op; 13.1, at 20 years post-op). Surgery by JIB resulted in a reduction of glucose and insulin values. Concomitantly there was an elevation of postprandial GIP and GLP-1 plasma concentrations. In the obese subjects 20 years after JIB both fasting and postprandial GIP and GLP-1 values were markedly elevated compared with the other three groups; and plasma glucose and insulin concentrations were maintained at normal levels. CONCLUSIONS: The improvement in glucose metabolism seen after JIB may be due to reduced insulin resistance after weight loss and/or increased levels of the incretin hormones GIP and GLP-1. Progressively, elevated levels of GIP and GLP-1 seem to be necessary to maintain glucose homeostasis at long-term follow-up after this procedure.

Adult↗
PubMed1997

Phosphoinositide metabolism in hereditary ovalocytic red blood cell membranes.

Metabolic depletion of hereditary ovalocytes leads, similar to normal red cells, to decreased intracellular concentrations of ATP and GSH as well as degradation of the phosphoinositides to phosphatidylinositol and diacylglycerol. In contrast to normal red cells, however, loss of ATP does not induce any gross shape transformations; even after extensive depletion the ovalocytes retain their initial elongated stomatocytic character. The mechanical properties of hereditary ovalocytes are associated with a deletion of nine amino acid residues in band 3. Since the deletion appears to increase the stiffness of a normally flexible region of band 3, connecting the N-terminal cytoplasmic domain with the membrane spanning domain, our results indicate that shape changes require a flexible attachment of the cytoskeleton to the membrane-spanning band 3. The results also imply that metabolism of phosphoinositide cannot be the only determinant of cell shape, as suggested by the bilayer-couple hypothesis, but also other factors are involved in metabolically induced shape transformations.

Adenosine Triphosphate↗
PubMed1997

Calcium-binding mechanism of human nonerythroid alpha-spectrin EF-structures.

We have used circular dichroism and 1H- and 15N-NMR spectroscopy to investigate calcium binding to the two EF-hands of human nonerythroid or alphaII-spectrin. Comparison of the 1H-NMR spectra from the peptide containing both EF-hands to the peptides containing the single EF-I and EF-II structures showed that both the structural and calcium-binding properties are significantly different. Further studies of the 121 amino acid peptide containing both EF-hands using circular dichroism and NMR showed that the binding of calcium ions induces conformational changes. To investigate the calcium-binding mechanism, the chemical shifts changes were recorded using multidimensional NMR spectroscopy during calcium titration. A total of 25 titration curves were obtained, each corresponding to the chemical shift changes of individual amino acid residues. The shapes of these titration curves were either hyperbolic or sigmoidal. Using factor analysis, two functions were extracted, one hyperbolic and one sigmoidal, which accounted for nearly all information present in the titration curves. By fitting the two functions to binding curves based on different binding models, we found that the binding mechanism is best described as sequential. Since the sigmoidal type was more pronounced in the titration curves corresponding to residues from the first EF-hand, we suggest that calcium binding to the first EF-hand is described by the sigmoidal function, and that the hyperbolic function describes calcium binding to the second EF-hand. Therefore, is seems likely that the second EF-hand must contain bound calcium before the first EF-hand can bind.

Amino Acid Sequence↗
PubMed1997

Gastrointestinal hormones and gastric emptying 20 years after jejunoileal bypass for massive obesity.

OBJECTIVE: Some studies have shown a more rapid gastric emptying in obese subjects. Six to twelve months after jejunoileal bypass (JIB) neurotensin (NT) and enteroglucagon have been shown to be elevated after food intake. These hormones, together with peptide YY (PYY) and glucagon-like peptide-1 (GLP-1) have been implicated in the reduction of upper gastrointestinal motility seen after infusion of nutrients into the ileum. AIM: To study if the postprandial gut hormone pattern and gastric emptying is altered 20 y after JIB. SUBJECTS: Seven subjects operated with JIB a mean (s.d.) 20 +/- 3 y ago, with a BMI of 44 +/- 4 kg/m2 at the time of surgery and 31 +/- 4 at present. For comparison seven sex-matched non-operated obese controls (BMI 43 +/- 3) were studied. METHODS: Serial blood samples were obtained every 10 min after intake of a 280 kcal meal. Radioimmunoassays for motilin, cholecystokinin (CCK), NT, PYY and GLP-1 were performed. Gastric emptying of a solid meal was studied using a radioactively labelled omelette (of 310 kcal) for 120 min). RESULTS: After JIB postprandial motilin, CCK, NT, PYY and GLP-1 were elevated compared to non-operated obese subjects. Similarly, basal levels of CCK, motilin, GLP-1 and PYY were elevated in the operated group. No difference was observed in the rate of gastric emptying between the two groups. CONCLUSION: Both fasting and postprandial gut hormone levels are elevated 20 y after JIB. The impact of long-term rapid stimulation of the ileum and subsequent raised gut hormone levels on gastric emptying is not clear.

Cholecystokinin↗
PubMed1997

Reduced food intake after jejunoileal bypass: a possible association with prolonged gastric emptying and altered gut hormone patterns.

The object of this study was to examine whether eating behavior, food preference, gastric emptying, and gut hormone patterns are altered after jejunoileal bypass (JIB) in patients with severe obesity. Eight obese [mean (+/- SD) body mass index (BMI; in kg/m2) 42.9 +/- 4] subjects were studied prospectively before and 9 mo after JIB with eight age- and sex-matched normal-weight control subjects. Total energy intake, data from the universal eating monitor (VIKTOR), eating motivation measured by visual analog scales, a food-preference checklist, a forced-choice list, solid-phase gastric emptying, and postprandial concentrations of cholecystokinin, motilin, and neurotensin were studied. BMI was reduced by 29% after JIB. Compared with normal subjects, the JIB patients showed a reduced desire to eat, decreased hunger, and reduced prospective consumption before a test meal. After surgery, obese subjects selected fewer food items and showed a reduced preference for high-carbohydrate and high-fat items before a test meal. There was a trend from an accelerated toward a decelerated eating pattern in obese subjects after JIB. After JIB, gastric emptying of obese subjects was slowed and similar to that in control subjects. Obese subjects had lower postprandial cholecystokinin concentrations that were lower than those of control subjects both before and after JIB. Postprandial concentrations of neurotensin were higher after JIB. We conclude that after JIB, the desire to eat and preference for high-carbohydrate and high-fat items is reduced, resulting in decreased energy intake. That gastric emptying is prolonged and gut hormone patterns are altered with low postprandial plasma cholecystokinin and high neurotensin plasma concentrations may at least partly account for these observations.

Adult↗
PubMed1997

The incidence of clinical postoperative thrombosis after gastric surgery for obesity during 16 years.

BACKGROUND: Suggested risk factors for postoperative thrombosis such as high fatty acid levels, hypercholesterolemia and diabetes are common in obese patients. METHODS: In a retrospective study, the case records of 328 patients operated for obesity by gastric procedure from September 1977 until December 1993 were analyzed: 253 women and 75 men with a mean age of 38 years and a mean body mass index (BMI) of 44 kg/m2. The operation time, use of epidural anesthesia, and the occurrence of risk factors; fatty acid levels, hypercholesterolemia and diabetes were recorded. Symptomatic thromboses were verified by phlebography or phlethysmography and pulmonary embolism with ventilation/perfusion scintigraphy or autopsy. RESULTS: The mean operating time was 128 minutes, 77% had epidural anesthesia and the mean hospital stay was 12.3 days. The long hospital stay was due to the fact that most patients took part in different scientific studies perioperatively. The incidence of thromboembolism was 2.4%. Four patients had pulmonary embolism, in one of them this was fatal. Three patients had deep leg vein thrombosis and one patient had arm thrombosis secondary to a central venous catheter. None of these patients had high fatty acids, diabetes or high cholesterol. Of the patients, 298 were given dextran-70 (Macrodex, Pharmacia) as prophylaxis, seven were given heparin and 23 were given no prophylaxis. In the patient group without diagnosed thrombosis, 31% had high fatty acid levels, 2% had high cholesterol levels and 9% had diabetes. CONCLUSIONS: Obese patients seem to have a moderate risk of developing postoperative thrombosis when an effective prophylaxis is used. High free fatty acids, hypercholesterolemia and diabetes are not obvious extra risk factors in obese patients. Thromboprophylaxis should be given to all operated obesity patients regardless of age. The surgeons must be aware and investigate promptly any symptoms suggestive of thromboembolism.

Adult↗
PubMed1997

Seven year results of vertical banded gastroplasty for morbid obesity.

OBJECTIVE: To present our experience with a group of obese patients treated by vertical banded gastroplasty. DESIGN: Open prospective study. SETTING: Teaching hospital, Sweden. SUBJECTS: 198 Morbidly obese patients operated on between 1986 and April 1994. INTERVENTIONS: Modified Mason vertical banded gastroplasty. MAIN OUTCOME MEASURES: Weight loss, mortality, early and late morbidity, and reoperation. RESULTS: The mean (SEM) age was 40 (0.7) and 149 of the 198 were women (75%). 22 Patients (11%) were lost to follow-up. Five patients died (3%), one soon after operation. Mean (SEM) body mass index (BMI) was 44.4 (0.5) preoperatively and this decreased to 32.6 (0.6) after four years (n = 99) and 33.8 (1.3) after seven years (n = 20). 21 patients developed 24 early postoperative complications, and 31 patients were reoperated on 41 times for late complications. CONCLUSION: All patients lost weight after vertical banded gastroplasty, and their weight continued to decrease during a seven-year follow-up. This was somewhat offset by the high rate of reoperations required.

Adolescent↗
PubMed1996

Gastric emptying of solids in humans: improved evaluation by Kaplan-Meier plots, with special reference to obesity and gender.

It has been suggested that obesity is associated with an altered rate of gastric emptying, and that there are also sex differences in gastric emptying. The results of earlier studies examining gastric emptying rates in obesity and in males and females have proved inconsistent. The aim of this study was to investigate the influence of obesity and gender on gastric emptying, by extending conventional evaluation methods with Kaplan-Meier plots, in order to assess whether these factors have to be accounted for when interpreting results of scintigraphic gastric emptying tests. Twenty-one normal-weight volunteers and nine obese subjects were fed a standardised technetium-99m labelled albumin omelette. Imaging data were acquired at 5- and 10-min intervals in both posterior and anterior projections with the subjects in the sitting position. The half-emptying time, analysed by Kaplan-Meier plot (log-rank test), were shorter in obese subjects compared to normal-weight subjects and later in females compared to males. Also, the lag-phase and half-emptying time were shorter in obese females than in normal females. This study shows an association between different gastric emptying rates and obesity and gender. Therefore, body mass index and gender have to be accounted for when interpreting results of scintigraphic gastric emptying studies.

Adult↗
PubMed1996

Is enteral nutrition optimally used in hospitalized patients? A study of the practice of nutrition in a Swedish hospital.

Thirty patients with parenteral nutrition were studied in order to evaluate if they could be given enteral nutrition instead. Based upon absolute and relative contraindications for enteral nutrition, we calculated that 80% of the patients were possible candidates for enteral nutrition. Long-term use of parenteral nutrition may cause complications. Besides metabolic and other advantages when enteral nutrition is used, economical gains are also important. We have calculated an estimated annual net profit of US$ 357,000 in our hospital, if enteral instead of parenteral feeding is used in patients suitable for the former type of feeding. This implies that it is really cost-beneficial to consider enteral nutrition in hospitalized patients. Although parenteral nutrition will continue to have its place in the management of different occasions, increased use of enteral nutrition may result in improved patient outcomes and improved cost-effectiveness.

Journal Article↗
PubMed1996

Six Cases of Barrett's Esophagus after Gastric Restrictive Surgery for Massive Obesity: An Extended Case Report.

OBJECTIVE: The purpose of this study is to report and characterize six patients who have developed Barrett's esophagus after; a gastric restrictive procedure for massive obesity. METHOD: Retrospective analysis of patients operated with gastric banding (GB) and vertical banded gastroplasty (VBG) between 1981 and 1994. RESULTS: Four patients (4/92) initially operated with GB have developed Barrett's esophagus a mean of 9 years post-operatively. Two patients (2/198) operated with VBG developed Barrett's esophagus 18 and 47 months postoperatively. The histopathological type of Barrett's esophagus was cardia-like in three cases, gastric-like in two cases and intestinal-like columnar epithelium in one case. None of the biopsies showed signs of dysplasia. CONCLUSION: Gastric banding is again gaining popularity with the development of adjustable bands that can be placed laparoscopically. The development of Barrett's esophagus after GB and VBG, a premalignant lesion, is cause for some concern. Prospective long-term studies are needed to further address this complication.

Journal Article↗
PubMed1996

Gastro-oesophageal reflux before and after vertical banded gastroplasty in the treatment of obesity.

OBJECTIVE: To study the long term effect of vertical banded gastroplasty on lower oesophageal sphincter pressure. DESIGN: Prospective study. SETTING: University hospital, Sweden. SUBJECTS: 21 morbidly obese patients (mean body mass index 42.5). INTERVENTIONS: Vertical banded gastroplasty, together with measurements of endoscopic grade, oesophageal manometry, and 24 hour pH before, and a mean of 38 months after, operation. MAIN OUTCOME MEASURES: Weight, grade of oesophagitis according to the Savary-Miller classification, number of episodes of reflux, percentage of time that the pH was < 4, and lower oesophageal sphincter pressure. RESULTS: Before operation 5/14 patients (36%) had evidence of oesophagitis, and 12/21 (57%) had evidence of reflux disease. Two patients had abnormally low lower oesophageal sphincter pressure ( < 10 mm Hg). A mean (SEM) of 32 months after operation (range 6-49) the mean body mass index was 32.7 (1.2), and after a mean of 38 months paired data showed that there had been no significant changes in manometric (n = 11) or 24 hour pH (n = 10) measurements, or in endoscopic grading (n = 7). CONCLUSION: Vertical banded gastroplasty used in the treatment of morbid obesity does not affect the antireflux function of the lower oesophageal sphincter.

Esophagitis, Peptic↗
PubMed1995

Activation of the plasma contact system and hemodynamic changes after graft revascularization in liver transplantation.

In this study, the relation between activation of the plasma contact system and hemodynamic changes during orthotopic liver transplantation was evaluated. Nineteen consecutive courses of OLT in 17 adult patients were investigated. Veno-venous bypass was used in all patients. Blood samples were drawn through all phases of the procedure, and analyzed for the following parameters using functional techniques (chromogenic peptide substrate assays): plasma kallikrein (KK), prekallikrein, functional plasma kallikrein inhibition, C1 inhibitor, and alpha 2-macroglobulin. Plasma high molecular weight kininogen (HK) degradation was evaluated using the immunoblotting technique. An abrupt rise in KK activities occurred within 1 min after portal reperfusion of the liver graft (7-16 U/L, P < 0.05). Simultaneously, proteolytic breakdown of HK was seen. The elevated KK activities were maintained the next 1 1/2 hr. Ten min after graft reperfusion, a significant increase in cardiac output compared with the anhepatic phase (7.2-12.4 L/min, P < 0.05) was found. At the same time, systemic vascular resistance fell significantly (817-408 dynes x sec/cm-5, P < 0.05). The increase in plasma KK activities accompanied by simultaneous degradation of HK seen immediately after reperfusion of the liver graft may be due to contact activation as recipient blood contacts with the underlying basement membrane of injured sinusoidal endothelium in the transplanted liver. We suggest that hemodynamic changes associated with the postreperfusion syndrome seen after revascularization of the liver in OLT could at least be caused in part by bradykinin release due to contact activation.

Adult↗