Effects of elevated carbon dioxide environment on calcium metabolism in humans.

BACKGROUND: Chronic respiratory acidosis induced by an elevated carbon dioxide (CO2) environment should provoke hypercalciuria with related total body and subsequent bone calcium losses. We examined this hypothesis in four healthy male volunteers, who were exposed during a 25-d period to an 0.7% CO2 environment within a deep diving isolation chamber. Three months later the same subjects were reexamined during a second campaign being exposed to a 1.2% CO2 atmosphere. METHODS: The subjects received a constant calcium intake (1.4 g.d-1) and vitamin D supplement (1000 IU.d-1) during both campaigns. Calcium balance (oral calcium intake minus urinary and fecal calcium output) was evaluated. Serum calcium concentrations and biomarkers of bone metabolism were measured, in order to evaluate bone turnover. Additionally, the response to an acute oral calcium load was examined as a sensitive measure of changes in calcium metabolism. RESULTS: Both, urinary calcium excretion (from 245 +/- 38 to 199 +/- 31 mg.d-1; mean +/- SE, 0.7% and 1.2%, respectively) and fecal calcium losses (from 1229 +/- 128 to 996 +/- 62 mg.d-1) were significantly reduced in the higher (1.2%) CO2 atmosphere. Although more calcium was retained in the body during the 1.2% than during the 0.7% CO2 campaign, serum calcium concentrations and biomarkers of bone formation were significantly lower in the higher CO2 campaign. Furthermore, bone resorption was slightly increased in the 1.2% experiment. CONCLUSION: Elevated CO2 atmosphere may dose-dependently preserve body calcium without a parallel improvement of bone substance.

[Operative technique and outcome in metabolic surgery: conventional and banded gastric bypass]. / Operative Technik und deren Outcome in der metabolischen Chirurgie: Konventioneller und Banded Gastric Bypass.

BACKGROUND: The prevalence of morbid obesity and its sequelae is increasing in Germany, Europe and worldwide. Bariatric surgery is thus gaining in importance for the treatment of patients with malignant obesity. Creation of a gastric bypass is one of the most frequently performed procedures for obesity. DISCUSSION: The gastric bypass has been used -since 1966 as a surgical means of weight reduction in obese patients. In the mean time various modifications have been developed. Thus, for example, the laparoscopic procedure represents the current standard. After the operation most patients experience an excess weight loss (EWL) of between 61 and 83 %. The comorbidities of obesity are also markedly improved and in a high percentage even cured after the operation. It is worthy of note that diabetes mellitus type II improves shortly after the operation even before any weight loss has occurred. The suggests that the operation induces more than "just" a loss of weight. CONCLUSION: For decades the gastric bypass has been a well known standard operation of overweight and, in addition to the reduction in weight, is also a therapy for diabetes mellitus -type II.

EEG controlled rapid opioid withdrawal under general anaesthesia.

We performed rapid opioid detoxification under propofol anaesthesia in 30 opioid addicts, using the opioid receptor antagonist naltrexone. Two strategies to obtain a sufficient depth of anaesthesia and to avoid anaesthetic overdose were evaluated. Patients were allocated randomly to one of two groups. In group 1, the effects of propofol were monitored by observing clinical signs, and in group 2, depth of anaesthesia was controlled using an EEG threshold method. Withdrawal symptoms and post-anaesthetic recovery time were assessed. All patients remained stable and no anaesthetic complications were noted. There were significant differences in the total dose of propofol given (group 1, mean 72 (SD 9) mg kg-1; group 2, 63 (8) mg kg-1; P < 0.01), duration of anaesthesia (318 (53) min vs 309 (42) min; P < 0.05), duration of recovery time (49 (13) min vs 40 (12) min; P < 0.01) and frequency of withdrawal symptoms between groups. In addition, the incidence of side effects was different between groups (62 vs 29 points on a withdrawal symptom scale; P < 0.01). To obtain a sufficient depth of anaesthesia but to avoid inappropriately large doses of anaesthetic, we consider that EEG monitoring is valuable during rapid opioid detoxification.