Ubiquitous atmospheric production of organic acids mediated by cloud droplets.

Atmospheric acidity is increasingly determined by carbon dioxide and organic acids1-3. Among the latter, formic acid facilitates the nucleation of cloud droplets4 and contributes to the acidity of clouds and rainwater1,5. At present, chemistry-climate models greatly underestimate the atmospheric burden of formic acid, because key processes related to its sources and sinks remain poorly understood2,6-9. Here we present atmospheric chamber experiments that show that formaldehyde is efficiently converted to gaseous formic acid via a multiphase pathway that involves its hydrated form, methanediol. In warm cloud droplets, methanediol undergoes fast outgassing but slow dehydration. Using a chemistry-climate model, we estimate that the gas-phase oxidation of methanediol produces up to four times more formic acid than all other known chemical sources combined. Our findings reconcile model predictions and measurements of formic acid abundance. The additional formic acid burden increases atmospheric acidity by reducing the pH of clouds and rainwater by up to 0.3. The diol mechanism presented here probably applies to other aldehydes and may help to explain the high atmospheric levels of other organic acids that affect aerosol growth and cloud evolution.

[Prosthetic care of proximal femur fractures]. / Prothetische Versorgung der proximalen Femurfrakturen.

The endoprosthetic replacement of the hip joint or its components in fractures of the proximal femur is a standard method. Indications for replacement are strongly dislocated intracapsular femoral neck fractures in elderly patients, fractures with an existing arthritis of the hip joint, and profound osteoporosis. Improved perioperative management and more gentle anesthetic techniques have helped to reduce perioperative mortality from nearly 50% to 11.5% over the last 40 years. As routine treatment options, the bipolar endoprosthesis without replacement of the acetabular joint surface and total hip replacement in case of degenerative arthritis of the acetabular joint surface are commonly used. The mere replacement of the femoral head with a simple femoral head prosthesis should be reserved for exceptional cases. For the implantation of a hip joint prosthesis and its uncomplicated post-treatment and long-term durability, careful preoperative planning is essential together with the selection of a suitable implant, its optimal bony fixation, avoidance of intra-operative complications and restoration of the anatomical landmarks such as the centre of rotation of the hip joint, the offset of the prosthetic shaft as well as leg length. Despite the high standard of endoprosthetics in Germany, the results are still improvable in comparison to other countries. Measures which preserve the joint as well as the bone will be increasingly important in prophylaxis of further complications. In addition, more attention should be paid to the prophylaxis of falls and a sufficiently guide-lined therapy of osteoporosis for the prophylaxis of fractures of the elderly.

Regional hemostatic status and blood requirements after total knee arthroplasty with and without tranexamic acid or aprotinin.

UNLABELLED: Antifibrinolytics seem to reduce postoperative blood loss after total knee arthroplasty. Few studies have shown the impact of these drugs on the mechanisms of coagulation. The purpose of this study was to examine coagulation/fibrinolysis variables as well as blood loss after total knee arthroplasty with and without antifibrinolytics in the operated limb on a regional level. Thirty-six patients were randomized into one of three groups to receive aprotinin, tranexamic acid, or no medication. We took blood samples of the femoral vein before deflating the tourniquet and after 5, 10, 30, 60, 120 min and on the first postoperative day. The implantation of a knee prosthesis in artificial ischemia caused a significant activation of coagulation and fibrinolysis in the regional circulation. Tranexamic acid and aprotinin did not cause a significant modulation of fibrinolysis variables or a significant reduction of postoperative bleeding and transfusion requirements. One of the differences in comparison to other studies was the decreased total blood loss. The use of bone cement as well as surgical hemostasis before wound closure may be regarded as reasons for this. Therefore, primarily these methods should be used because there is no increased risk of adverse drug effects. IMPLICATIONS: After total knee arthroplasty total blood loss may be kept in a low range if methods such as cemented knee prosthesis and surgical hemostasis are used. In this case aprotinin and tranexamic acid did not cause a significant modulation of fibrinolysis variables or a significant reduction of postoperative bleeding.

[Gallbladder carcinoma--an unexpected finding after laparoscopic cholecystectomy]. / Das Gallenblasenkarzinom--ein unerwarteter Befund nach laparoskopischer Cholezystektomie.

The carcinoma of the gallbladder can be found mostly in a late stage. We have to expect a incidental carcinoma of the gallbladder in 1-2% after conventional cholecystectomy. We report 9 cases of unexpected carcinoma of the gallbladder after 1700 laparoscopic cholecystectomies. The time of survival were--dependent on tumor stage--2 to 36 month. We outline special items of this disease within the context of minimal-invasiv surgery.

[Incidental gallbladder carcinoma--a report of experiences after 1,200 laparoscopic cholecystectomies]. / Das unerwartete Gallenblasenkarzinom--ein Erfahrungsbericht nach 1200 laparoskopischen Cholezystektomien.

Incidental carcinoma of the gallbladder can be found histologically in 1-2% of specimens after surgery of benign diseases of the hepatobiliary tract. We present our results of 7 cases of incidental gallbladder carcinoma in 1200 laparoscopic cholecystectomies. Surgical treatment and clinical outcome are reported. We tried to outline special items of this disease within the context of minimal-invasive surgery.