Acute Effects of Calcitonin Nasal Spray on Serum C-telopeptide of Type 1 Collagen (CTx) Levels in Elderly Osteopenic Women with Increased Bone Turnover

Salmon calcitonin is a potent inhibitor of osteoclastic activity. The effect of calcitonin in elderly women with high bone turnover at higher risk of developing osteoporosis has not been studied. To investigate acute effects of calcitonin treatment on bone resorption markers in elderly women, we conducted a randomized trial in women >65 years of age with high bone turnover assessed as urinary N-telopeptide of type-I collagen (NTx) levels 1 SD higher than mean premenopausal levels, which was irrespective of bone density. A total of 98 elderly women were randomly assigned to receive either 200 IU calcitonin nasal spray (n = 75) with calcium (500 mg) and vitamin D (200 IU) or calcium and vitamin D (n = 23) alone for 6 months. Blood and urine samples were collected at 0, 2, 4, and 6 months and analyzed for urinary NTx and serum C-telopeptide of type-1 collagen (CTx). At baseline, mean age was 72.1 ± 4.7 (mean ± SD) in the calcitonin group and 72.2 ± 6 years in the control group. The spine and total hip BMD, serum PTH levels and urinary calcium/creatinine ratios were similar in both groups. Mean BMD was in the osteopenic range in both groups. Calcitonin treatment resulted in significant decreases in serum CTx levels, 2, 4 and 6 months after treatment as compared to baseline, and after 4 and 6 months as compared to controls. A maximum decrease from baseline of 33% was seen at 6 months. The urinary resorption marker, urine NTx, showed a significant decrease in the calcitonin group when compared to baseline only at the 6-month time point. Analysis of least significance change (LSC) showed that 70% of calcitonin patients were categorized as responders using serum CTx after 6 months of treatment. We conclude that 200 IU calcitonin effectively decreases bone resorption within 60 days of therapy, thus preventing further bone loss in elderly women who are at a high risk of developing osteoporosis.     

Medical informatics in an undergraduate curriculum: a qualitative study

Background  

There is strong support for educating physicians in medical informatics, and the benefits of such education have been clearly identified. Despite this, North American medical schools do not routinely provide education in medical informatics.     

Hepatic and colonic perforation by an abandoned ventriculoperitoneal shunt

We report a case of an abandoned distal limb of a ventriculoperitoneal shunt that resulted in hepatic as well as colonic perforation in a 12-year-old girl. Although it is common practice at the time of shunt revision to leave a retained distal catheter in the peritoneal cavity, we suggest this can result in perforation of solid as well as hollow viscera.     

Pneumothorax during laparoscopy

Background: Pneumothorax is a known complication of laparoscopy, with most pneumothoraces diagnosed postoperatively with conventional chest x-ray. Electrocardiogram (ECG) conduction changes are associated with pneumothorax. In a sheep model, ECG changes were evaluated as a potential indicator of intraoperative pneumothorax. Additionally, resolution rates of helium (He) and carbon dioxide (CO₂) pneumothorax were also evaluated in this model.Methods: Under general anesthesia, 10 sheep had known volumes (20–100 cc) of either He or CO₂ introduced into the left hemithorax. A 12-lead ECG recorded changes associated with the induced pneumothorax. After changes in the ECG plateaued, the gas volume in the hemithorax was increased to 2 L and the resultant pneumothorax was followed for a 2-h period using fluoroscopy to determine resolution rates for the different gas pneumothoraces. Gas volumes were aspirated after 2 h and ECGs were again recorded.Results: Pneumothorax volumes as low as 20 cc produced consistent ECG changes. The amplitude of the precordial QRS complex was seen to diminish, and this lowering of the QRS amplitude continued as pneumothorax volume increased up to 100 cc. The ECG returned to prepneumothorax patterns with aspiration of the left chest. For different gas pneumothoraces, CO₂ pneumothorax showed almost complete resolution in the 2-h period, whereas He pneumothorax was unchanged.Conclusions: Precordial ECG changes appear to be a very sensitive indicator of pneumothorax, with very small pneumothorax (<100 cc) consistently being detected by reduction of the QRS complex amplitude. Intraoperative use of precordial ECG leads could result in rapid identification of pneumothorax during laparoscopic surgery. Carbon dioxide pneumothorax shows near 100% resolution in a 2-h period. This supports recommendations of expectant management in asymptomatic patients with CO₂ pneumothorax. However, He pneumothorax does not resolve spontaneously quickly and may require aspiration even in asymptomatic patients.     

Association study between Alzheimer’s disease and genes involved in Aβ biosynthesis,aggregation and degradation: suggestive results with BACE1

Background Amyloid -peptide (A) biosynthesis, aggregation and degradation constitute three important steps to consider in the study of pathological mechanisms involved in Alzheimers disease (AD). Several proteins have been suggested as involved in each of these processes: proteolytic cleavage of the amyloid precursor protein by the -site APP cleaving enzyme (BACE), increased amyloid fibril formation by the activity of the acetylcholinesterase (ACHE gene), and degradation of A aggregates by the plasmin system have been exhaustively documented.Methods A case-control design was used to evaluate the possible association between candidate genes involved in these three processes and AD. We analysed three polymorphisms located at the BACE1 gene, one polymorphism at the ACHE gene, and two variants located at the tissue plasminogen activator and plasminogen activator inhibitor-1 (genes TPA and PAI- 1, respectively), both part of the plasmin system.Results We found an association between BACE1 exon 5 GG genotype and AD (ageand gender-adjusted odds ratio = 2.14, P =0.014). Although a similar association was reported previously by Nowotny and collaborators only in subjects carrying the 4-allele of the apolipoprotein E gene (APOE), we did not detect this effect. However,when we combined our results with those previously reported, a clear increase of the risk to develop AD appeared in subjects carrying both the BACE1 exon 5 GG genotype and the APOE 4-allele (crude OR = 2.2, P = 0.004).Conclusion These data suggest a possible genetic relation between BACE1 and AD.