Early effects of acetazolamide on hemoglobin mass and plasma volume in chronic mountain sickness at 5100 m

INTRODUCTION AND OBJECTIVES

Chronic Mountain Sickness (CMS) syndrome, combining excessive erythrocytosis and clinical symptoms in highlanders, remains a public health concern in high-altitude areas, especially in the Andes, with limited therapeutic approaches. The objectives of this study were to assess in CMS-highlanders permanently living in La Rinconada (5100-5300 m, Peru, the highest city in the world), the early efficacy of acetazolamide (ACZ) and atorvastatin to reduce hematocrit (Hct), as well as the underlying mechanisms focusing on intravascular volumes.

MATERIALS AND METHODS

Forty-one males (46±8 years of age) permanently living in La Rinconada for 15 [10-20] years and suffering from CMS were randomized between ACZ (250 mg once-daily; N = 13), atorvastatin (20 mg once-daily; N = 14) or placebo (N = 14) uptake in a double-blinded parallel study. Hematocrit (primary endpoint) as well as arterial blood gasses, total hemoglobin mass (Hb_mass) and intravascular volumes were assessed at baseline and after a mean (±SD) treatment duration of 19±2 days.

RESULTS

ACZ increased PaO₂ by +13.4% (95% CI: 4.3 to 22.5%) and decreased Hct by -5.2% (95% CI: -8.3 to -2.2%), whereas Hct remained unchanged with placebo or atorvastatin. ACZ tended to decrease Hb_mass (-2.6%, 95% CI: -5.7 to 0.5%), decreased total red blood cell volume (RBCV, -5.3%, 95% CI: -10.3 to -0.3%) and increased plasma volume (PV, +17.6%, 95% CI: 4.9 to 30.3%). Atorvastatin had no effect on intravascular volumes, while Hb_mass and RBCV increased in the placebo group (+6.1%, 95% CI: 4.2 to 7.9% and +7.0%, 95%CI: 2.7 to 11.4%, respectively).

CONCLUSIONS

Short-term ACZ uptake was effective to reduce Hct in CMS-highlanders living at extreme altitude >5,000 m and was associated with both an increase in PV and a reduction in RBCV.

The levonorgestrel intrauterine system for prevention of endometrial cancer in women with obesity: A cost-effectiveness study

OBJECTIVE

To estimate the cost-effectiveness of the levonorgestrel intrauterine system (LNG-IUS) as an endometrial cancer prevention strategy in women with obesity.

METHODS

A Markov decision-analytic model was used to compare 5 strategies in women with a body mass index of 30 or greater: 1) Usual care 2) LNG-IUS for 5 years 3) LNG-IUS for 7 years 4) LNG-IUS for 5 years, replaced once for a total of 10 years 5) LNG-IUS for 7 years, replaced once for a total of 14 years. Obesity was presumed to be associated with a 3-fold relative risk of endometrial cancer incidence and a 2.65-fold disease-specific mortality. The LNG-IUS was assumed to confer a 50% reduction in cancer incidence over the period of the LNG-IUS insertion. Outcomes were incremental cost-effectiveness ratios, calculated in 2019 Canadian dollars (CAD) per year of life saved. One-way and two-way sensitivity analyses were performed.

RESULTS

The LNG-IUS strategy was considered cost-effective if the cost of the intervention is less than $66,400 CAD ($50,000 US dollars) per year of life saved. The strategy becomes cost-effective if the LNG-IUS is inserted at age 57 (strategy #2), at age 52 for strategy #3, at age 51 for strategy #4 and at age 45 for strategy #5, when compared to usual care. The results are stable to variations in cost but sensitive to the estimated risk reduction of the LNG-IUS and the impact of obesity on endometrial cancer incidence and disease-specific mortality.

CONCLUSION

The LNG-IUS is a cost-effective method of endometrial cancer prevention in women with obesity.

Traumatic avulsion of the triceps brachii

Traumatic avulsion of the triceps brachii tendon is a rare injury. Clinical diagnosis shows that elbow extension against gravity is not possible. Radiologically, the lateral elbow may show the presence of flecks of avulsed osseous material from the olecranon ("flake sign"), which is almost pathognomonic of this lesion. The authors of the present study present a case of avulsion fracture treated with the attachment of bone suture anchors.

Fibronectin-induced intracellular calcium rise in Entamoeba histolytica trophozoites: effect on adhesion and the actin cytoskeleton

The interaction of Entamoeba histolytica trophozoites with fibronectin (FN) promotes adhesion of the protein to the cells and its later degradation by locally released proteases. Binding to FN-covered surfaces induces, in addition, the formation of actin adhesion plates and focal contacts in the amebas. The signaling mechanisms underlying the response to FN are incompletely understood. In this paper we examined the modifications of cytosolic free calcium ([Ca2+]i) induced in the trophozoites by the interaction with FN and their effect on adhesion and the actin cytoskeleton organization. FN produced a sustained rise of [Ca2+]i that could be correlated to the incremented adhesion to FN-covered surfaces. Further increments in [Ca2+]i produced by Ca2+ ionophores A23187 or ionomycin significantly increased the adhesion of trophozoites, whereas depletion of cytoplasmic Ca2+, by treatment with the ionophores in the absence of external Ca2+ or using the chelator BAPTA/AM, blocked it almost completely. To study the role of internal calcium we used the plant lactone thapsigargin, which was found to produce a transient increase of [Ca2+]i but a low stimulatory effect on adhesion and the organization of actin plates. The shifting of soluble actin to the F-actin form and the stabilization of adhesion plates and focal contacts, seen as results, of the FN stimulus, were positively influenced by rises in [Ca2+]i and negatively affected by its decrement. Additional evidence for Ca2+ -mediated signaling in the response to FN was provided by the poor adhesion and defective actin plate organization observed in trophozoites treated with calmodulin antagonists. The results presented here suggest that FN action is mainly dependent on the influx of external Ca2+.

Intergeneric hybrids of Saccharomyces cerevisiae and Zygosaccharomyces fermentati obtained by protoplast fusion

To obtain strains that are able to efficiently produce ethanol from different carbohydrates, mainly cellulose hydrolysates, several species of the genus Candida and a Zygosaccharomyces fermentati strain were examined for their ability to utilize cellobiose and produce ethanol, as well as for their thermotolerance and the possibility of genetic manipulation. Candida obtusa and Zygosaccharomyces fermentati tolerated the maximal temperature for growth, possessed the highest cellobiase activity, and offered the possibility of genetic manipulation, although neither of them proved to be a good producer of ethanol. Intergeneric hybrids of Saccharomyces cerevisiae and Z. fermentati were obtained after protoplast fusion. They were selected as prototrophic strains, after isolation of auxotrophic mutants from Z. fermentati and fusion with an S. cerevisiae strain which was also auxotrophic. The hybrids, which appeared at a frequency of 2 X 10(-7), presented characteristics of both parents, such as resistance to certain drugs and the ability to grow with either cellobiose or lactic acid as the sole carbon source; they were very stable, even under nonselective conditions. These hybrids may have important industrial applications as good fermenting strains.