Polysomnography before and after weight loss in obese patients with severe sleep apnea

OBJECTIVE

While obstructive sleep apnea (OSA) is strongly related to obesity, few studies have examined polysomnographic (PSG) changes with major weight loss. We examined the effect of weight loss following laparoscopic adjustable gastric banding (LAGB) on the PSG changes in patients with severe OSA. In addition, we studied daytime sleepiness, the metabolic syndrome and quality of life (QOL).

METHODS

A prospective study was conducted of 25 severely obese patients (17 men, eight women) with paired diagnostic PSG, biochemical and questionnaire studies, the first prior to LAGB and the second at least 1 y later. Subjects with a baseline apnea-hypopnea index (AHI) >25/h were included.

RESULTS

Subject baseline age was 44.7 y, weight 154 kg and body mass index 52.7 kg/m(2). The second PSG study was conducted 17.7+/-10 (range 12-42) months after surgery and mean percentage of excess loss and weight loss were 50.1+/-15% (range 24-80%) and 44.9+/-22 kg (range 18-103 kg), respectively. There was a significant fall in AHI from 61.6+/-34 to 13.4+/-13, improved sleep architecture with increased REM and stage III and IV sleep, daytime sleepiness, as measured by Epworth Sleepiness Scale, of 13+/-7.0 to 3.8+/-3.0, and fewer patients requiring nasal continuous positive airways pressure (CPAP). There were also major improvements in the metabolic syndrome, QOL, body image and fewer symptoms of depression (P<0.05 for all).

CONCLUSION

Weight loss provides major improvement or resolution of OSA and CPAP requirements. It also reduces daytime sleepiness, and improves the metabolic syndrome and QOL. LAGB placement should be considered a broadly effective therapy for sleep apnea in the severely obese patient.

Body composition changes following laparoscopic gastric banding for morbid obesity

Most reports of outcome following obesity surgery report weight and co-morbidity changes only. We studied body composition changes in 17 adult patients (15 F, 2 M, age 43+/-2 years, range 28-58 years), with morbid obesity (initial BMI 40.4+/-4.9 kg/m(2), range 34.7-48.8) who were managed surgically by laparoscopically inserting an adjustable gastric band. Body composition was studied before and after surgery (mean interval of 909+/-51 days, range 441-1155 days) using anthropometry (abdominal circumference, AC, sum of four skinfold thicknesses, SFSUM), whole-body potassium counting (TBK), in vivo neutron activation analysis total body nitrogen (TBProtein) and whole-body dual-energy ray absorptiometry (total body percent fat TBF%, and total body bone mineral density TBBMD). Weight loss over the study period was 23.4+/-2.5 kg. ( p<0.0003) with an AC reduction of 20.0+/-4.5 cm ( p<0.008). Both SFSUM and TBF% were significantly reduced ( p<0.02 and p<0.0005 respectively). Both TBK and TBProtein after normalization for sex and height, were significantly ( p<0.0054 and p<0.001 respectively) reduced, but the ratio of loss of fat mass to fat-free mass, at 4.4:1 was usual for weight loss, and there was no significant changes in the ratio of potassium to protein. TBBMD, after normalization relative to a young same sex adult, was not significantly changed. In this group of patients, most of the substantial weight loss over a 2- to 3-year period was due to loss of fat mass, with relatively less reduction in the components of fat-free mass. Adjustable laparoscopic gastric banding induces fat loss without significant other deleterious effects on body composition.

Improvements in insulin sensitivity and beta-cell function (HOMA) with weight loss in the severely obese. Homeostatic model assessment

AIMS

To examine the effect of weight loss on insulin sensitivity and beta-cell function in severely obese subjects of varying glycaemic control.

PATIENTS AND METHODS

Subjects were 254 (F:M 209:45) patients having adjustable gastric banding for severe obesity, with paired biochemical data from before operation and at 1-year follow up. The homeostatic model assessment method was used to calculate insulin sensitivity (HOMA%S) and beta-cell function (HOMA%B). Subjects were grouped by diabetic status and by pre-weight loss HbA1c.

RESULTS

Initial mean (sd) weight and body mass index were 128 (26) kg and 46.2 (7.7) kg/m2, respectively, and at 1-year were 101 (22) kg and 36.4 (6.7) kg/m2. The percentage of excess weight lost (%EWL) was 44.3 (14)%. HOMA%S improved from 37.5 (16)% presurgery to 62 (25)% (P < 0.001). %EWL was the only predictor of HOMA%S improvement (r = 0.28, P < 0.001). Subjects with normal fasting glucose, impaired fasting glucose and Type 2 diabetes had a fall, no change and increase in HOMA%B, respectively. The improvement in HOMA%B in subjects with diabetes (n = 39) was inversely related to the time with diabetes (r = -0.36, P = 0.02). In non-diabetic subjects the HOMA%S-HOMA%B relationship was favourably altered with weight loss, so that for any given HOMA%S there was an increase in HOMA%B (f = 11.8, P = 0.001). This improvement in HOMA%B was positively related to %EWL (r = 0.25, P = 0.019).

DISCUSSION

There are beneficial changes in both insulin sensitivity and beta-cell function with weight loss. Modern laparoscopic obesity surgery may have an important early role in the management of Type 2 diabetes in obese subjects.

Molecular configurations and orientations of hydrazine between structural layers of kaolinite

Hydrazine is one of the most commonly used entraining agents to penetrate kaolinite, yet the mechanism of intercalation of kaolinite by hydrazine is still in debate. The objectives of this study are to investigate the possible molecular configurations and orientations of hydrazine in the interlayer of kaolinite and the configuration changes induced by water molecules. Water molecules increased the intercalation rate and caused the expansion of the intercalation complex from 0.96 to 1.03 nm. The kinetic effect was likely the result of breaking the self-associations of hydrazine molecules and releasing more "free" hydrazine molecules for the intercalation. H-bonding caused large red shifts of the inner surface OH stretching bands from 3695 to 3626 cm(-1) in the 0.96-nm kaolinite hydrazine intercalation (KHI) complex and to 3570 and 3463 cm(-1) in the 1.03-nm KHI complex. The NH stretching bands of the hydrazine molecules in the KHI complexes became sharper and blue-shifted more than 20 cm(-1) compared with the free liquids. The symmetric NH vibrations at 3365 and 3310 cm(-1), and the NN vibration at 1092 cm(-1) became infrared inactive in the 0.96-nm KHI complex. The frequency of the SiO bands of the kaolinite in the 1.03-nm KHI complex was slightly lower than in the 0.96-nm KHI complex (5 cm(-1) shift). These IR band changes implied that hydrazine molecules have different configurations in the complexes: hydrazine molecules had an eclipsed form in the interlayer of the 0.96-nm KHI complex. The eclipsed configuration has a dipole moment of 3.31 D, which is higher than the gauche form (1.83-1.90 D). The molecule was oriented with the NN bond parallel or nearly parallel to the (001) surface of the mineral and the four H atoms of each hydrazine molecule reacted with the basal siloxane surface. When a suitable amount of water was present, it promoted the configuration change of the hydrazine molecules from the eclipsed form to the common gauche form. This gauche form was stabilized by transforming to a more polarized NH3NH tautomer structure (5.4 D). To promote an optimal interaction between hydrazine and the mineral surface, the NN bond of the hydrazine was tilted about 30 degrees from the (001) plane and caused the intercalation complex to expand from 0.96 to 1.03 nm. The eclipsed form and the tautomer were stabilized by the asymmetric interlayer environment of kaolinite. The two proposed models and reaction mechanisms match the high dipole moment requirement as found for other entraining agents. Further investigation is needed to confirm the exact configuration of hydrazine molecules and whether or not the tautomer exists.

Reduced plasma homocysteine in obese red wine consumers: a potential contributor to reduced cardiovascular risk status

BACKGROUND

Moderate alcohol consumption is associated with improved vascular risk profile and decreased mortality in the middle aged. An elevated homocysteine concentration is an independent risk factor for cardiovascular disease.

OBJECTIVE

To examine the relationship between alcohol consumption and homocysteine concentrations in severely obese patients (body mass index (BMI)>35).

DESIGN

A careful alcohol history was obtained from 350 (male:female 1:5) consecutive patients as part of preoperative assessment for surgical treatment of obesity. Data were obtained concerning amount, frequency, timing and type of alcohol consumption. Fasting homocysteine, serum folate and vitamin B(12) concentrations were measured. Differences between groups were assessed using Student t-test, and ANOVA. Linear regression was used to assess factors influencing homocysteine concentration.

RESULTS

There is a U-shaped relationship between alcohol consumption and homocysteine concentrations, with light to moderate consumption being associated with lower concentrations. Those consuming <100 g/week (n=165) of alcohol had geometric mean (95% CI of mean) serum homocysteine concentrations of 8.5 (8.2-8.9) micromol/l compared with 9.5 (9.1-9.9) micromol/l for non or rare consumers (n=153; P=0.001). The lower concentrations of homocysteine in regular consumers were associated with higher folate concentrations of 9.4 (8.6-10.2) ng/ml when compared with non-consumers 7.5 (7.1-7.8) ng/ml (P=0.001). Red wine consumers (n=42) had lower fasting concentrations of homocysteine 7.8 (7.5-8.1) micromol/l compared with 153 non-consumers 9.4 (9.0-9.8) micromol/l (P<0.001), 82 beer and spirit consumers 9.0 (8.4-9.7) micromol/l (P=0.005) and 73 white wine consumers 8.8 (8.2-9.4 micromol/l (P=0.013). Red wine consumption was an independent predictor for lower homocysteine concentrations.

CONCLUSION

Mild to moderate alcohol consumption, especially red wine consumption, in obese subjects is associated with lower fasting homocysteine concentrations. This may reduce cardiovascular risk and help explain the 'French paradox'.

Effect of Structural Stress on the Intercalation Rate of Kaolinite

Particle size in kaolinite intercalation showed an inverse reactivity trend compared with most chemical reactions: finer particles had lower reactivity and some of the fine particles cannot be intercalated. Although this phenomenon was noted in the early 1960s and several hypotheses have been reported, there is no widely accepted theory about the unusual particle size response in the intercalation. We propose that structural stress is a controlling factor in the intercalation and the stress contributes to the higher reactivity of the coarser particles. In this study, we checked the structural deformation spectroscopically and indirectly proved the structural stress hypothesis. A Georgia kaolinite was separated into nine size fractions and their intercalations by hydrazine monohydrate and potassium acetate were investigated with X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) analyses. The apical Si-O band of kaolinite at 1115 cm(-1) shifted to 1124 cm(-1) when the mineral was intercalated to 1.03 nm by hydrazine monohydrate, and its strong pleochroic properties became much weaker. Similar reduction in pleochroism was observed on the surface OH bands of kaolinite after intercalation. Both the bending vibrations of the inner OH group at 914 cm(-1) and of the surface OH group at 937 cm(-1) shifted to 903 cm(-1) after intercalation by hydrazine. A new band for the inner OH group appeared at 3611 cm(-1) during the deintercalation of the 1.03 nm hydrazine kaolinite complex. Pleochroism change in the apical Si-O band suggested the tetrahedra had increased tilt with respect to the (001) plane. The tilt of the Si-O apical bond could occur only if the octahedra had also undergone structural rearrangement during intercalation. These changes in the octahedral and tetrahedral sheets represent some change in the manner of compensation for the structural misfit of the tetrahedral sheet and octahedral sheet. As the lateral dimensions of a kaolinite particle increases, the cumulative degree of misfit increases. Intercalation breaks the hydrogen bonds between layers and allows for the structure to reduce the accumulated stress in some other manner. The reversed size effect on intercalation probably was not caused by crystallinity differences as reported in the literature, because the Hinckley and Lietard crystallinity indices of the four clay fractions were very close to each other. Impurities, such as dickite- or nacrite-like phases are not significant in the studied sample as suggested by the XRD and IR results, they are not the main reasons for the lower reactivity of the finer particles.

Echinococcus granulosus: regulation of leukocyte growth by living protoscoleces from horses, sheep, and cattle

To determine whether living hydatid tissue can, like hydatid fluid, regulate leukocyte growth, T-cell, B-cell, and macrophage lines were cocultured with protoscoleces of Echinococcus granulosus and their growth was compared with that of control cultures by thymidine uptake estimates and chemiluminescent assays of cell number. Protoscoleces supported mitosis of IL-1-deprived D10 T cells, but did not increase D10 count. The action of protoscoleces was affected by the species and organ of their origin and the length of time in culture. Unusually marked mitotic reaction, unaffected by parasite age and origin, was recorded in the B-cell line, BSM, also without commensurate count increase, indicating that induced mitosis resulted in cell loss. It is concluded that protoscoleces can induce mitosis in B and T cells of particular lineages and that this is a potential means of producing the pathological proliferation and depletion of B- and T-cell areas which characterize local reaction to hydatids.

Quality of life after lap-band placement: influence of time, weight loss, and comorbidities

OBJECTIVE

To assess the quality of life (QOL) in severely obese subjects before and after Lap-Band gastric restrictive surgery and identify factors that may influence change.

RESEARCH METHODS AND PROCEDURES

All patients, over a 3-year period, attending for preoperative assessment (n = 459) or annual review after surgery (n = 641) have completed the Short Form-36 (SF-36) health survey. Eight domain and physical component summary (PCS) and mental component summary (MCS) scores were calculated. Scores were analyzed in groups based on time after surgery and compared with community normal (CN) values. Paired preoperative and 1-year scores (n = 218) data were used to find predictors of QOL change.

RESULTS

All preoperative mean scores (n = 459) were lower than CN values, with greater impairment in the PCS (36.8 +/- 9.5 vs. CN: 51.3 +/- 8.3, p < 0.001) than in the MCS (45.7 +/- 8.2 vs. CN: 48.8 +/- 9.5, p < 0.001) scores. After 1 year, scores were closer to CN scores (PCS: 52.4 +/- 8.2 and MCS: 48.4 +/- 7.7), and these remained closer for 4 years. Preoperative obesity comorbidity, especially physical disability, was the best predictor of poor preoperative SF-36 scores and of improvement in scores at 1 year. The percentage of excess weight loss at 1 year (46 +/- 16%) was of little predictive value of improved QOL.

DISCUSSION

Severely obese subjects have poor health-related QOL as measured by the SF-36 health survey. Lap-Band surgery for this group has provided a dramatic and sustained improvement in all measures of the SF-36. Improvement is greater in those with greater preoperative disability, and the extent of weight loss is not a good predictor of improved QOL.

Pregnancy after Lap-Band surgery: management of the band to achieve healthy weight outcomes

BACKGROUND

Severely obese women have higher obstetric risks and poorer neonatal outcomes. Weight loss reduces obstetric risk. The introduction of a laparoscopically-placed adjustable gastric band, a safe and effective method of weight loss, has given us the ability and responsibility to adjust the band in relation to pregnancy.

OBJECTIVE

Our aim was to devise a safe management plan to achieve healthy maternal weight gain (Institute of Medicine 1990) during pregnancy.

METHODS

In a cohort group of 650 patients to have a Lap-Band placement for severe obesity, we have reviewed the management of the band and pregnancy outcomes of all women (n=20) to complete a pregnancy (n=22) with a band in-situ.

RESULTS

All 22 pregnancies were singleton, with no primary caesarean sections (3 for recurring indications). The mean maternal weight gain was 8.3 kg compared with 15.2 kg for the 15 previous pregnancies of women in this group (p<0.05). There was no difference in birth weights. Obstetric complications were minimal, and there were no premature or low birth weight infants. 11 of 15 subjects with active management of the band achieved a maternal weight gain within the advised range compared with only 2 of 7 prior to this.

CONCLUSION

The ability to adjust gastric restriction allows optimal control of maternal weight change in pregnancy and should help avoid the risks of excessive weight change.

Nonalcoholic fatty liver disease: predictors of nonalcoholic steatohepatitis and liver fibrosis in the severely obese

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease (NAFLD) is common in severely obese subjects and can progress to cirrhosis and liver failure. Predicting advanced or progressive disease may help in selecting patients for liver biopsy and assist the development of therapeutic options.

METHODS

Liver biopsies were taken at laparoscopic obesity surgery in 105 consecutive patients. The clinical and biochemical variables were analyzed for correlation with specific histologic features.

RESULTS

Twenty-six patients (25%) were found to have nonalcoholic steatohepatitis (NASH), and 11 (42%) of these had advanced fibrosis. A raised index of insulin resistance (odds ratio [OR] 9.3, 95% confidence interval [CI] 3.4-26), systemic hypertension (OR 5.2, 95% CI 2.0-13.5), and raised alanine aminotransferase (OR 8.6, 95% CI 3.1-23.5) were independent predictors of NASH. A combination of 2 or 3 of these predictors allows a sensitivity of 0.8 and specificity of 0.89 for NASH. Alcohol consumption was associated with a reduction in NASH (OR 0.35, 95% CI 0.12-1.00) and diabetes (OR 0.18, 95% CI 0.047-0.67).

CONCLUSION

Insulin resistance and systemic hypertension, features of the metabolic syndrome, are independently associated with advanced forms of NAFLD. Moderate alcohol consumption seems to reduce the risk of NAFLD in the severely obese, possibly by reducing insulin resistance.

A disparity between conventional lipid and insulin resistance markers at body mass index levels greater than 34 kg/m(2)

OBJECTIVE

The aim of this study was to examine changes in lipid profile and markers of insulin resistance with increasing body mass index (BMI) in the range 34-77 kg/m(2). In addition we compare the lipid profiles of severely obese patients with those of the Australian community.

SUBJECTS AND METHODS

A total of 572 patients (85% F, 15% M) were assessed prior to gastric restrictive surgery. Conventional lipid profiles and markers of insulin resistance were measured. Lipids were compared with the Australian National Heart Foundation 1989 study (control group).

RESULT

There was no difference in mean total cholesterol levels between the obese group (5.52 mmol/l) and the control group (5.47 mmol/l). The mean total cholesterol levels in the obese group fell with increasing BMI (r=-0.13, P<0.01). Obese subjects had elevated fasting triglyceride levels 1.96 mmol/l (control group, 1.12 mmol/l, P<0.001), but levels did not change with increasing BMI (r=0.0, NS). HDL-C levels were lower, 1.21 mmol/l (control group 1.44 mmol/l, P<0.001), and decreased with increasing BMI (r=-0.20, P<0.01). LDL-C levels were lower in obese men (3.65 mmol/l vs control group 4.17 mmol/l, P<0.01) but not women and levels fell with increasing BMI (r=-0.15, P<0.05). For the obese group, markers of insulin resistance (fasting plasma glucose, HbA1c, fasting plasma insulin and C-peptide) all rose significantly with increasing BMI.

CONCLUSION

Raised total cholesterol is not a co-morbidity of severe obesity. There is a disparity between the conventional lipid measures and insulin resistance measures of the metabolic syndrome with increasing BMI. Conventional lipid measures may be poor indicators of dyslipidaemic risk in the severely obese.

Mitosis and differentiation in T-cells under cytotoxic action of Echinococcus granulosus hydatid fluid

In the T-cell line, D10, thymidine uptake was used to measure the proportion of cells in S-phase, and the MTT assay to measure the number of viable cells. The effect of Echinococcus granulosus hydatid fluid (HF) on the lymphocytes was assayed in 3-day cultures of the T-cell line, D10, in increasing concentrations of HF. Apparent cytotoxic effects of HF were recorded as a log-linear decline in S-phase activity, which was reduced by the presence of IL-1, IL-2, or a combination of the two. In the presence of IL-2, however, mitogenic treatment with concanavalin A increased the cytotoxic effect in 3-day cultures, while in day-2 cultures, HF itself showed mitogenic effect. HF-induced decline in S-phase activity was not matched by a parallel decline in viable cells, suggesting that the apparent cytotoxicity of HF could result from cell-cycle arrest. Depending on its origin, HF enhanced membrane expression of CD25 and CD38 on human peripheral blood lymphoblasts, and diminished that of CD28. Taken together, these changes suggest that HF can induce T-cell mitosis and reduce co-stimulation with subsequent T-cell anergy or apoptosis.

Pre-operative predictors of weight loss at 1-year after Lap-Band surgery

BACKGROUND

The authors studied a range of preoperative factors for their predictive value of effectiveness of Lap-Band placement, using the percentage of excess weight loss at 1-year as the outcome measure (%EWL1).

METHODS

All factors were measured and recorded prior to surgery. Factors included: patient demographics, family, medical and weight history. Laboratory measures and the responses to the SF-36 Health Survey were also assessed. Factors were assessed for correlation with %EWL1.

RESULTS

The group (N=440, F:M 383:57) had mean age 40.0+/-9.5 years, weight of 126+/-25 kg, and BMI 45.6+/-7.5 kg/m2 pre-operatively. At 1-year follow-up, the group had mean weight 97.6< or =20 kg, BMI 35.6 = 6.3 kg/m2, and %EWL1 45.8< or =17%. Increasing age (R= -0.13, p<0.01) and preoperative BMI (R=-0.22, p<0.001) were significantly associated with less %EWL1 and all other factors were controlled for these before assessing significance. Important factors associated with a lower %EWL1 included: hyperinsulinemia (R=-0.36, p<0.001), insulin resistance (R=-0.33, p<0.001) and disease associated with insulin resistance, poor physical ability, pain, and poor general health responses to the SF-36 Health Survey. Patients who consumed alcohol regularly had a better rate of weight loss (R= 0.23, p<0.005). Factors that had no influence included gender, a history of mental illness and measures of mental health, previous bariatric surgery, and a history of many medical conditions associated with obesity.

CONCLUSION

Important physical factors have been found to influence the rate of weight loss. Those with increased age, pain, physical disability and insulin resistance have a great deal to gain from weight loss. Although this study has identified factors that are associated with less weight loss, we have not found any factor that predicts an unacceptably low weight loss and thus provides a contraindication to Lap-Band placement. The findings of this study allow us to set more realistic goals for the rate of weight loss in specified sub-groups of our patients.

Elevated homocysteine levels with weight loss after Lap-Band surgery: higher folate and vitamin B12 levels required to maintain homocysteine level

OBJECTIVE

To investigate homocysteine levels and their relationship with serum folate and vitamin B12 concentrations with weight loss after the Lap-Band form of gastric restrictive surgery, with the view to minimizing risk.

METHODS

We measured levels of fasting plasma homocysteine (tHcy), folate (serum and RBC) and vitamin B12 in two groups. The study group was 293 consecutive patients at 12 (n=192) or 24 (n=101) months review after surgery. The controls were 244 consecutive patients presenting for this surgery.

RESULTS

The group losing weight had higher geometric mean tHcy levels: 10.4 (95% CI, 9.8-10.8) micromol/l compared with 9.2 (95% CI, 8.9-9.7) in controls (P<0.001). This occurred with higher folate levels and unchanged vitamin B12 levels. Levels of folate and B12 together explained 35% (r (2)) of the homocysteine variance in the weight loss group compared with only 9% (r (2)) in controls (P<0.001). Those taking regular multivitamin supplements had lower tHcy levels: 9.6 (9.1-10.0) micromol/l vs 12.3 (11.4-13.3) in those not taking supplements (P<0.001). A low normal plateau of tHcy levels occurred at levels of folate >15 ng/l and B12)600 ng/ml. A curvilinear relationship exists between these cofactors and tHcy levels, with the dose-response relationship shifted to the right in the weight loss group.

CONCLUSION

This study shows elevated tHcy levels with weight loss, without lower serum folate or vitamin B(12) levels. There is an altered dose-response relationship with higher serum B(12) and folate levels required to maintain recommended tHcy levels. Patients losing weight have significant health benefits; however, they may be at greater risk of vascular events or fetal abnormality in association with raised tHcy levels. Multivitamin supplementation is effective in lowering tHcy levels.

Sleep disturbance and obesity: changes following surgically induced weight loss

BACKGROUND

Obesity causes sleep disturbance and is the most significant risk factor for sleep apnea. Only surgical methods provide substantial sustained weight loss for most severely obese subjects.

OBJECTIVE

To study sleep disturbance in patients undergoing laparoscopic adjustable gastric banding with a commercially available product (Lap-Band).

METHODS

In this study, 313 consecutive patients with severe obesity (body mass index [calculated as weight in kilograms divided by the square of height in meters] >35) completed a preoperative sleep questionnaire and clinical assessment. One hundred twenty-three patients completed the same assessment 12 months after surgery. The characteristics of sleep disturbance and changes in responses to weight loss have been assessed.

RESULTS

There was a high prevalence of significantly disturbed sleep in men (59%) and women (45%), with women less likely to have had their sleep disturbance investigated. Observed sleep apnea was more common in men, but daytime sleepiness was not affected by sex. Waist circumference was the best clinical measure predicting observed sleep apnea (R = 0.36; P<.001). The group lost an average of 48% (SD, 16%) of excess weight by 12 months. There was a significant improvement in the responses to all questions at follow-up, with habitual snoring reduced to 14% (preoperative value, 82%), observed sleep apnea to 2% (preoperative value, 33%), abnormal daytime sleepiness to 4% (preoperative value, 39%), and poor sleep quality to 2% (preoperative value, 39%) (P<.001 for all).

CONCLUSIONS

Obesity-related sleep disorders improve markedly with weight loss. Sustainable weight loss should be a primary aim in the management of severely obese patients with significant sleep disturbance, including sleep apnea. Low-risk laparoscopic obesity surgery should be considered for selected patients with this important comorbidity.

Growth kinetics of leukocyte cell lines cultured with hydatid fluid of Echinococcus granulosus equinus

Oxidation of 3,(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and tritiated thymidine uptake were used to measure, respectively, the viable cell count and the S-phase activity of D10, B9, A20 and p388d leukocytic cell lines cultured in the presence of varying concentrations of fluid from fertile and infertile hydatid cysts of Echinococcus granulosus equinus. Exposure to hydatid fluid raised or lowered the entry of D10 cells into S-phase depending on the concentration of the fluid and of the supporting cytokines. Enlargement of the S-phase population was unaccompanied by increase in viable count indicating that the mitotic cycles induced by hydatid products were not completed. A similar conclusion was reached in respect of the p388d monocytic line, and both changes appear consistent with those occurring in histopathology in vivo. By contrast, the main effect on B9 and A20 B cells was inhibition of entry into S-phase.

Echinococcus granulosus: assays for hydatid immunoregulatory factors using established lymphoid cell lines

Mitosis, mitochondrial metabolic rate and proliferation were measured in established lymphoid cell lines exposed to chromatographic fractions of equine Echinococcus granulosus hydatid fluid. In several cell lines, one or more of the three parameters were modified by the exposure. As an assay for potential immunoregulatory activity, the method was simple and repeatable. The following novel observations were made: (1) Mitotic reaction was found among lines of T-cell, B-cell and macrophage origin; (2) mitosis was accompanied by proliferation in the B-cell lines, B9 and A20, and in the macrophage lines, HL-60 and P388d. With mitotically responsive T-cells, proliferation was slight in CTLL-2 and absent in D10, implying cell-cycle modification; (3) mitotic responsiveness tended to occur in cell lines with mature characteristics; (4) among cytokine-dependent cell lines, hydatid fluid FPLC fraction 1 mimicked IL-1 and several fractions mimicked IL-2 and IL-6 in the maintenance of mitosis; and (5) there was significant statistical interaction between the influences of mammalian cytokines and hydatid fluid fractions, implying that the propensity of antigenically unprimed lymphoid cells to be regulated by E. granulosus is conditioned by cytokine activity.

Anaemia, diarrhoea and opportunistic infections in Fell ponies

This report summarises clinical and pathological observations on Fell pony foals with a range of signs that included ill thrift, anaemia, respiratory infection, glossal hyperkeratosis and diarrhoea. Some of the foals had normochromic, normocytic anaemia and some had low levels of plasma proteins, including immunoglobulin G. Antibiotic and supportive treatment was ineffective and all affected foals died or were killed on humane grounds. Postmortem examination of 12 foals and tissues from 2 other foals revealed a range of lesions that included glossal hyperkeratosis, typhlocolitis, intestinal cryptosporidiosis, granulomatous enteritis, proliferative and necrotising bronchiolitis consistent with adenovirus infection; lesions similar to those in the respiratory tract were present in the salivary gland and pancreas of individual foals. Lymphoid tissue was judged to be smaller than expected. These observations suggest the possibility of opportunistic infections secondary to some form of undefined immunocompromised state.

Gastroesophageal reflux in obesity: the effect of lap-band placement

BACKGROUND

Gastroesophageal reflux disease (GERD) is a common condition which is often aggravated by morbid obesity. Lap-Band surgery provides effective weight loss in the morbidly obese. There have been several reports that gastric banding causes or aggravates reflux. The aim of this study was to evaluate the effect of Lap-Band placement on GERD.

METHODS

All patients with a significant history of GERD who had a Lap-Band inserted over a 2-year period were evaluated postoperatively to assess any change in impact on reflux. Resolution required absence of reflux symptoms and no anti-reflux drug therapy.

RESULTS

There were 48 (16%) of 274 consecutive patients with a significant history of reflux esophagitis requiring regular therapy preoperatively. The median age was 39 (range 23-58) and M:F ratio was 5:43. We confirm a high prevalence of GERD in patients with morbid obesity: 17% with symptoms requiring regular therapy (Community Norm 7%). Total resolution of all reflux symptoms occurred in 36 (76%) patients, improvement in 7 (14%), no change in 3 (6%), and aggravation of symptoms in 2 (4%). Patients with severe and moderate symptoms had similar improvement. Resolution or improvement was reported soon after surgery.

CONCLUSION

Rapid and major improvement in symptoms of GERD occurs after Lap-Band placement. The placement of the band probably acts directly to reduce reflux. This result contrasts with reports which have found gastric banding causes or aggravates GERD.

Marked improvement in asthma after Lap-Band surgery for morbid obesity

BACKGROUND

Asthma and morbid obesity are common chronic conditions that may be related. Laparoscopic banding provides effective weight control of morbid obesity. The aim of this study was to evaluate the prevalence of asthma in the morbidly obese and the changes in asthma after laparoscopic adjustable gastric banding (LAGB) (Lap-Band) surgery for morbid obesity.

METHODS

Asthma was assessed preoperatively in all patients presenting for LAGB. 32 consecutive asthmatic patients were followed up clinically and by a standard questionnaire at least 12 months after surgery, and any change in asthma impact was recorded.

RESULTS

The prevalence of the doctors' diagnosis of asthma was 24.6% (73 of 296 consecutive patients). This was significantly higher than the prevalence in the Australian community of 12% to 13% (P < 0.001). The 32 patients who were followed up had a mean body weight of 125.2 kg and a body mass index (BMI) of 45.7 kg/m2 prior to operation, and a weight of 89.3 kg (BMI 32.9 kg/m2) at follow-up. All 32 patients recorded a lower asthma score postoperatively. There were significant improvements in all aspects of asthma assessed. These included severity, daily impact, medications needed, hospitalization, sleep, and exercise. The mean preoperative scaled asthma score was 44.5 +/- 16. There was a highly significant reduction at follow-up to a mean value of 14.3 +/- 11 (P < 0.001).

CONCLUSIONS

There is a high prevalence of asthma in morbidly obese adults, and major reductions in asthma severity occur after Lap-Band(r) surgery and weight loss. Mechanisms other than direct weight loss appear to play a part in this improvement. Prevention of gastroesophageal reflux may be an important factor.

Effect of transportation and weaning on humoral immune responses of calves

Transportation exposes cattle to stress and results in increased morbidity and mortality. An investigation was made of the effects of transport and another important stressor, weaning, on the immune function of calves by determining humoral immune responses to keyhole limpet haemocyanin (KLH). In a 2 x 2 factorial designed experiment, suckled calves were either (1) weaned at housing (day 0) and not transported, (2) weaned at housing and transported, (3) weaned while still at pasture nine to 13 days prior to housing and not transported or (4) weaned at pasture and transported. All calves were immunized with KLH at housing (day 0) and serum samples were collected subsequently to determine class and subclass anti-KLH antibody responses (IgG1, IgG2, IgA and IgM) by direct ELISA. Increased anti-KLH IgG1 and IgG2 concentrations were shown in calves that were weaned prior to housing and transported on day 10 (P < 0.05 and P < 0.01 respectively). Transported calves had increased IgG1 concentrations on day 20 (P < 0.05) compared with calves that were not transported. However, calves weaned at housing and not transported had increased IgA and IgM responses on day 30 compared with the other groups of calves (P < 0.05). This study shows that transportation and weaning affect the humoral immune responses of suckler calves and that the effects persist for several weeks. However, the effects of the treatments were not consistent for all antibody classes measured.

Immunological activities of a lymphocyte mitogen isolated from coenurus fluid of Taenia multiceps (Cestoda)

The purification of a mitogen from Taenia multiceps coenurus fluid has been previously reported. In the present study, this activity, which was independent of endotoxin, stimulated the expression of lymphocyte IL-2 and Fc receptors, enhanced mitotic response to phylohaemogglutinin and concanavalin A and antagonised the previously described suppressive effects of the macrophage modifying fraction of coenurus fluid. The mitogen also increased peritoneal macrophage count and viability, Fc receptor expression and Fc receptor-mediated phagocytosis. The mitogenic activity could be destroyed by a combination of protease and amylase, but not by either enzyme alone. It is suggested that the mitogen forms part of a homeostatic mechanism for the preservation of a balanced host-parasite relationship.

Echinococcosis

Hydatids, the intermediate stages, or metacestodes, of the tapeworm genus, Echinococcus, present a major immunological problem; they survive, grow and metastasize in immunized hosts which are protected against reinfection and possess effector mechanisms capable of killing the parasite. Explanations for this state of concomitant immunity have been made from investigations of avoidance strategies, genetics and quantitative hydatid growth. The latter study suggests that the host-parasite relationship is sustained as a dynamic equilibrium between parasite growth and acquired immunity, the balance being subject to mutual regulation and including the possibility of spontaneous rejection of the parasite. Two immunoregulatory, or cytokine-like, factors have been detected in hydatids of Echinococcus spp. One appears to be a mediator of the previously reported mitogenic effects of hydatids. Recent evidence has linked these effects to generation of T-suppressor populations. The second factor interferes with the interaction of macrophages and T-cells, mimics the effect of metacestode infection in impairing the accessory action of macrophages in lymphoproliferative responses, and is suppressive for rosette-forming cell responses against third-party antigens. It is suggested that these factors form part of a primary homeostatic mechanism regulating hydatid growth and immunity.