Environmental drivers of increased ecosystem respiration in a warming tundra.

Arctic and alpine tundra ecosystems are large reservoirs of organic carbon1,2. Climate warming may stimulate ecosystem respiration and release carbon into the atmosphere3,4. The magnitude and persistency of this stimulation and the environmental mechanisms that drive its variation remain uncertain5-7. This hampers the accuracy of global land carbon-climate feedback projections7,8. Here we synthesize 136 datasets from 56 open-top chamber in situ warming experiments located at 28 arctic and alpine tundra sites which have been running for less than 1 year up to 25 years. We show that a mean rise of 1.4 °C [confidence interval (CI) 0.9-2.0 °C] in air and 0.4 °C [CI 0.2-0.7 °C] in soil temperature results in an increase in growing season ecosystem respiration by 30% [CI 22-38%] (n = 136). Our findings indicate that the stimulation of ecosystem respiration was due to increases in both plant-related and microbial respiration (n = 9) and continued for at least 25 years (n = 136). The magnitude of the warming effects on respiration was driven by variation in warming-induced changes in local soil conditions, that is, changes in total nitrogen concentration and pH and by context-dependent spatial variation in these conditions, in particular total nitrogen concentration and the carbon:nitrogen ratio. Tundra sites with stronger nitrogen limitations and sites in which warming had stimulated plant and microbial nutrient turnover seemed particularly sensitive in their respiration response to warming. The results highlight the importance of local soil conditions and warming-induced changes therein for future climatic impacts on respiration.

Presentation of 6 cases with parathyroid cysts and discussion of the literature.

INTRODUCTION: Cystic lesions of the parathyroid glands are uncommon, and rare are those that cause primary hyperparathyroidism. Preoperative diagnosis can be challenging and some of these tumors might be misinterpreted as parathyroid carcinoma. With an expertise of more than 1700 patients operated on primary hyperparathyroidism, we present six cases with cystic degeneration of a parathyroid gland causing primary hyperparathyroidism in five patients. CASE REPORTS: A woman at the age of 67 presented with hypercalcaemic crisis due to persistent primary hyperparathyroidism after an operation four years ago. As cervical exploration was unsuccessful, sternotomy was performed and a cystic adenoma of a parathyroid gland could be resected from the anterior mediastinum. The second patient - a 63-year-old female with severe hypercalcaemic crisis, operated on under suspicion of a parathyroid carcinoma - had a functional cyst of the parathyroid gland with a parathyroid hormone level of 700,000 pg/ml in the aspirated fluid. Third, operation on a 70-year-old woman with a benign euthyreot goiter and the laboratory findings of primary hyperparathyroidism revealed a cystic adenoma adjacent to the thyroid gland, whose aspirate had a parathyroid hormone level of 1,500,000 pg/ml. In the fourth case of a 67-year-old female with an adenoma of the right inferior parathyroid gland localized by ultrasonography, the cystic parathyroid adenoma was operated on by video-assistance. A cystic structure in the upper mediastinum was diagnosed in the fifth patient, a 66-year-old woman. It was suspected to be a thyroid cyst at the left-lower pole of the thyroid gland. After hemithyroidectomy pathological evaluation revealed a large parathyroid cyst. The last case of a 56-year-old male illustrates the extensive preoperative work-up of a patient with primary hyperparathyroidism who was preoperatively diagnosed as having a thyroid cyst. Final histopathological examination exposed multiple gland disease with a parathyroid adenoma as well as a cystic parathyroid gland. DISCUSSION: Cystic adenomas of the parathyroid glands are often misdiagnosed as thyroid cysts or - in the case of extremely elevated parathyroid hormone levels - even as parathyroid carcinoma. The routine preoperative diagnostic tools, such as ultrasonography or (99m)Tc-sestamibi-scintigraphy, cannot clearly distinguish between these entities and might be jeopardized by mediastinal localization, which is not uncommon in parathyroid adenomas with cystic degeneration.

Reciprocal formation of plastocyanin and cytochrome c-553 and the influence of cupric ions on photosynthetic electron transport.

The green alga Scenedesmus acutus is able to synthesize plastocyanin and cytochrome c-553. The concentrations of plastocyanin and cytochrome c-553 vary inversely in response to the cupric-ion concentrations of the growth medium (Bohner, H. and Böger, P. (1978) FEBS Lett. 85, 337-339). Both proteins form a homogeneous donor pool to the reaction center of Photosystem I. This donor pool can be varied quantitatively and qualitatively by different growth conditions. These variations have no influence on algal growth or photosynthetic electron transport as measured in vivo by oxygen evolution, fluorescence induction and cytochrome f-553 and c-553 redox reactions using Cu2+ concentrations of less than 10 microM in the culture medium. At higher cupric-ion concentrations, which already retard algal growth, specific sites of the photosynthetic electron-transport chain are affected: the oxidizing side of Photosystem II and the reducing side of Photosystem I.

Formation of silver plastocyanin in Scenedesmus.

Silver ions up to 5 microM do not affect growth of the green microalga Scenedesmus acutus. They induce formation of protein species precipitable by an antibody specific against plastocyanin. The metal is incorporated into a part of the induced protein in competition with copper. Bismuth, lead and molybdenum had no effect. The amount of both silver- and copper-containing plastocyanins so formed apparently regulates concurrently inhibition of soluble plastidic cytochrome c-553. The silver-copper competition for the build-up of blue plastocyanin can be shown with intact cells, not with isolated algal plastocyanin.

Nasal continuous positive airway pressure: A method to avoid endotracheal reintubation in postoperative high-risk patients with severe nonhypercapnic oxygenation failure.

OBJECTIVES: To study whether nasal continuous positive airway pressure (nCPAP) improves pulmonary oxygen transfer and avoids reintubation in patients with severe nonhypercapnic oxygenation failure after major cardiac, vascular, or abdominal surgery. DESIGN: Prospective interventional study. SETTING: Surgical ICU of a university hospital. PATIENTS: Twenty consecutive patients after thoracic, abdominal, or combined thoracoabdominal operations, in whom pulmonary oxygen transfer deteriorated continuously following elective extubation after initial mechanical ventilation. Respiratory failure was due to atelectasis and/or left heart failure, and all patients met predefined criteria for reintubation. INTERVENTIONS: nCPAP therapy (8 to 10 cm H(2)O) was initiated if PaO(2) had decreased to < 80 mm Hg despite application of 100% oxygen (flow, 25 L/min), intermittent mask continuous positive airway pressure, and maximum conventional therapy. MEASUREMENTS AND RESULTS: nCPAP treatment was started 24.1 +/- 3.4 h after elective extubation. PaO(2) was < 80 mm Hg in all patients, in 13 patients it was < 60 mm Hg, and in 3 patients it was < 50 mm Hg. Mean PaO(2)/fraction of inspired oxygen (FIO(2)) ratio had decreased to 60 +/- 2.6, and increased within the first hour of nCPAP to 136 +/- 12 (p < 0.001). The clinical condition in all patients improved further, and after 35.2 +/- 6.3 h, all patients were well oxygenated by face mask at ambient pressure (PaO(2)/FIO(2) ratio, 146 +/- 14). Two patients were reintubated for reasons unrelated to oxygenation or ventilation (data are presented as mean +/- SEM). CONCLUSIONS: nCPAP is safe, easy to apply, and effective to improve arterial blood oxygenation in < 1 h in postoperative patients with severe nonhypercapnic oxygenation failure. In these patients, who otherwise would have been reintubated, nCPAP can avoid endotracheal reintubation and mechanical ventilation.

Relative bioavailability of different butamirate citrate preparations after single dose oral administration to 18 healthy volunteers.

Eighteen volunteers have been treated with different oral formulations of butamirate citrate according to 2 randomized 2-way crossover designs. In the first study (study I) the test preparation was a syrup (Demotussol Hustensirup, Demopharm), and the reference preparation was a syrup already marketed (Sinecod Sirup, Zyma SA). A test preparation (Demotussol Tabletten) was compared to a solution (Demotussol Hustentropfen) in the second study (study II). Within the 2 study periods the volunteers received single 45 mg doses of the test and the reference formulation, respectively. Blood samples have been drawn immediately prior to each administration and at 17 sampling points within 96 h after dosing. A wash-out period of 1 week was maintained between successive drug doses. The plasma concentration of one of the main metabolites, 2-phenylbutyric acid, was determined by a validated reversed-phase HPLC method with UV detection, with a lower limit of quantification of 50 ng/ml. The following mean values have been obtained in study I (syrup preparations) for the test: AUC0-infinity 46.9 micrograms x h/ml, Cmax of 1.77 micrograms/ml at 1.1 h, t1/2 28 h and after administration of the reference: AUC0-infinity 50.4 micrograms x h/ml, Cmax 1.86 micrograms/ml, tmax 1.5 h, t1/2 26 h. In study II the following mean values have been obtained for the test preparation (tablet): AUC0-infinity 54.7 micrograms x h/ml, Cmax of 1.88 micrograms/ml at 1.1 h, t1/2 27 h and for the reference (solution): AUC0-infinity 54.5 micrograms x h/ml, Cmax 1.94 micrograms/ml, tmax 1.1 h, t1/2 26 h. Both preparations have been proven to be bioequivalent to their corresponding references regarding extent and rate of absorption.

[Current diagnosis and therapy of non-occlusive mesenteric ischemia]. / Aktuelle Diagnostik und Therapie der nicht okklusiven mesenterialen Ischämie.

PURPOSE: Non-occlusive mesenteric ischemia (NOMI) is a life threatening disease. Therapy and prognosis depend upon the length of time elapsed between primary clinical manifestation and the time of definitive diagnosis and treatment. MATERIALS AND METHODS: NOMI was diagnosed by intraarterial selective angiography in four patients. After a bolus administration of 20 g Alprostadil (Prostavasin) into the superior mesenteric artery, intraarterial perfusion was continued with 60 microg Alprostadil/day via the catheter for three days. RESULTS: The mesenteric ischemia resolved in all patients. One patient recovered completely. Three patients recovered from mesenteric ischemia, but died subsequently due to complications of their primary diseases. CONCLUSION: When NOMI without perforation or necrosis of the bowel wall is suspected clinically, immediate intraarterial angiography is the diagnostic method of choice. If NOMI is confirmed, the appropriate treatment is the intraarterial application of potent vasodilators for several days. The diagnostic work-up in suspected NOMI and the impact of different radiological examinations are explained. The literature is reviewed.

Detection and prognosis of recurrent gastric cancer--is routine follow-up after gastrectomy worthwhile?

BACKGROUND/AIMS: Although routine follow-up after surgery for gastric cancer is recommended its value after gastrectomy has not been evaluated. METHODOLOGY: All patients who underwent gastrectomy for gastric cancer entering the routine follow-up program between January 1987 and August 1996 were identified. The patients studied were those with either histologically proven recurrence or those in whom recurrence was highly probable from clinical course. Two groups were compared. The first group comprised the patients whose recurrence was detected by routine follow-up prior to the development of clinical signs (asymptomatic group). The second group consisted of the patients who developed clinical symptoms due to a recurrence that was detected subsequently (symptomatic group). The main parameters were the time until recurrence occurred, the pattern of recurrence, treatment and survival. RESULTS: Out of 184 patients entering the routine follow-up 135 patients had undergone potentially curative gastrectomy. Sixty-seven patients (49.6%) had recurrences. Only 15 (22.3%) belonged to the asymptomatic group and 52 (77.7%) to the symptomatic one. The time until recurrence occurred was not different between the 2 groups (17.1 vs. 18.0 months). Chemotherapy was performed more frequently in the asymptomatic group and survival was longer (8.4 vs. 5.9 months). This difference was due to the time the patients remained asymptomatic (average 43 months). No effect of either early detection or chemotherapy was seen. In the asymptomatic group distant recurrence was common while recurrence in the symptomatic group was more often local but this difference did not reach statistic significance. CONCLUSIONS: Routine follow-up after gastrectomy for gastric cancer does not contribute to early detection of gastric cancer recurrence. It has no benefit with respect to treatment and survival of patients with recurrent disease and should therefore be reduced to symptomatic and psychological aftercare.

Neurogenic appendicopathy in children.

BACKGROUND: In a prospective multicenter study, we could show that neurogenic appendicopathy is a histological entity. This study compares the general and the pediatric population with respect to clinical presentation and incidence of neurogenic appendicopathy (NA). METHODS: Included were patients that underwent appendectomy for suspected appendicitis, excluded were patients younger than 6 years and patients with missing data. Neurogenic appendicopathy was diagnosed by S-100 immunochemistry and/or haematoxylineosin (H.E.) staining. Two age groups (< or = 14 y and > 14 y) were compared with respect to the frequency of NA. RESULTS: In only four cases out of 84 children (4.8%) did we find neurogenic appendicopathy compared to 48 patients (24.2 %) out of 198 adolescents and adults. In the subgroup with negative appendectomy, the frequency of NA was 16.7% (< or = 14 years) and 56.6% (> 14 years). A clinical differentiation between neurogenic appendicopathy and acute appendicitis was not possible because of the small sample size. CONCLUSION: Neurogenic appendicopathy is a very rare histopathological entity in children. History and clinical examination do not make it possible for us to differentiate preoperatively between acute appendicitis and neurogenic appendicopathy.

[Computer-assisted case-based education in surgery]. / Computergestützte fallbasierte Lehre in der Chirurgie.

INTRODUCTION: Computer technology is well established in the fields of medical diagnosis and monitoring. In recent years, there has also been an increase in the use of computers for the purpose of medical education. METHODS: With the aid of the "author's-system" CASUS, investigation of a case of acute abdominal pain was integrated into the practical medical training for students in the 4th. year of clinical studies. For patient history, clinical examination and laboratory tests, the method involves the use of 41 cards with pictorial and acoustic information (text, graphics, sound recordings and videos), including 23 questions to be answered by the students. At the end of the session, the acceptance, effectiveness and practicability of the computer-based training was evaluated by a questionnaire. RESULTS: In 356 students, a high rate of acceptance and satisfaction was achieved (positive judgement of various aspects: 55%-98%). Technical difficulties which occurred initially were overcome during the course of the evaluation. Some questions were answered more positively by female students. CONCLUSION: Most students share the view that computer-based training, though not able to take the place of bedside teaching, is a valuable addition to the armamentum of medical teaching.

[Splenectomy in osteomyelofibrosis. Indications and outcome]. / Splenektomie bei Osteomyelofibrose. Indikationen und Ergebnisse.

Osteomyelofibrosis is a myeloproliferative disorder in which fibrosis and sclerosis finally lead to bone marrow obliteration. Liver and spleen compensate for bone marrow loss with extramedullary hematopoiesis. In some patients the resulting splenomegaly causes severe symptoms such as local compression, thrombocytopenia and hemolytic anemia. In such patients, splenectomy is the only promising treatment, although it represents a significant risk.

[Delirium increases morbidity and length of stay after vascular surgery operations. Results of a prospective study]. / Delirien erhöhen die Morbidität und die Liegezeit nach gefässchirurgischen Operationen. Ergebnisse einer prospektiven Untersuchung.

OBJECTIVE: We intended to analyze the influence of postoperative delirium on postoperative morbidity and length of hospital stay. PATIENTS AND METHOD: 153 patients undergoing elective arterial surgery were studied prospectively. Patients were examined postoperatively by a psychiatrist daily from days 1 to 7. Delirium was diagnosed according to standardised criteria (Diagnostic and Statistical Manual of Mental Disorders). The severity of delirium was quantified using the Delirium Rating Scale. We compared patients without delirium to those who developed postoperative delirium using univariate statistical analysis (t-test, chi (2) test, and Fisher's test). RESULTS: Sixty patients (39.2%) developed postoperative delirium. They removed catheters significantly more frequently than patients without delirium and had more catheter-related infections. Their length of stay in intensive care units was higher, as was their total postoperative length of stay in hospital. CONCLUSIONS: Patients who developed postoperative delirium have significantly more complications and increased postoperative length of stay in hospital and intensive care units.

[Life threatening complication after transthoracic esophageal resection]. / Lebensbedrohliche Komplikation nach transthorakaler Oesophagusresektion.

Acute inflow stasis of the vena cava superior is an emergency case. Because of the rapidly rising venous pressure, life-threatening complications can arise (e.g. cerebral hemorrhage, hemorrhagic venous infarcts). The main cause of central venous thrombosis is bronchial carcinoma (incidence: 3-5%). Iatrogenic reasons are thrombosis caused by pacemaker electrodes, dialysis catheter, central vein catheters, implanted ports and radiation-induced venous fibrosis. In this case a patient with an esophageal carcinoma was pretreated by a neoadjuvant chemoradiotherapy. The chemotherapy was given through a venous access port, which was implanted earlier. Radiation therapy with a total of 60 Gy followed. After the esophagectomy the patient developed an acute inflow stasis of the vena cava superior.

[Aortoiliac reconstruction after kidney transplantation. Strategies to avoid ischemic damage of the transplant]. / Rekonstruktion der aortoiliakalen Strombahn bei Patienten nach Nierentransplantation. Strategien zur Vermeidung einer ischämischen Transplantatschädigung.

INTRODUCTION: The rising life expectancy of patients undergoing kidney transplantation and the improvement in the function rate of the allografts have led to an increasing number of patients suffering from arteriosclerosis-related diseases of the aortoiliac arteries. In these particular cases, an interruption of the blood supply of the allograft is always necessary for operative repair of the aortic and iliac arteries. This means a high risk of ischemic damage to the transplanted kidney. PATIENTS AND METHODS: Between 1987 and 2000, 1,076 kidney transplantations were performed in our department. During this time, 14 reconstructive operations of the aortoiliac arteries were performed in 12 patients (6 women, 6 men, average age 55.2 (45-71) years). Operations were indicated in patients suffering from occlusive disease with imminent extremity or allograft loss, and symptomatic or asymptomatic aneurysms with a maximum diameter of more than 4 cm. In patients presenting with thoracoabdominal (1) and abdominal aortic aneurysms (3), protection of the transplanted kidney was performed by axilloiliac or axillofemoral bypass. Hypothermic flush-perfusion of the allograft containing PGE1 and heparin was performed in seven of nine operations for occlusive disease. RESULTS: None of the patients presented with a permanent decrease in kidney function, six patients showed temporary creatinine elevation, and in nine patients creatinine levels at discharge were lower than they were preoperatively. None of the patients died. CONCLUSION: Reviewing all reported methods of allograft protection, we recommend a three-step strategy including sequential clamp technique (ischemia < 30 min.), hypothermic flush-perfusion (ischemia < or = 60 min.), and temporary axilloiliac/femoral shunt (ischemia > 60 min), depending on the expected renal ischemia time.

[Endoscopic ultrasound in routine clinical practice for staging adenocarcinomas of the stomach and distal esophagus]. / Endosonographie in der klinischen Routine beim Adenokarzinom des distalen Osophagus und Magens. Eine ernüchternde Bilanz.

PROBLEM: Endoscopic ultrasound (EUS) is an important diagnostic tool for determining the best therapeutic strategy (primary resection, neoadjuvant therapy or palliation only) to offer esophageal or gastric cancer patients. PATIENTS AND METHODS: In the present study (1992-2001),we evaluated the accuracy of EUS in adenocarcinomas of the distal esophagus and stomach and compared our results with pathologists findings as the gold standard. RESULTS: Of the 222 patients studied, the precise examination of 11% EUS was not completely possible due to severe tumor stenosis. The accuracy of EUS with respect to T, N+/- and TN+/- amounted to 51%, 65% and 34% in 131 patients with adenocarcinomas of the esophageal gastric junction and to 50%, 66% and 37% in 91 patients with adenocarcinomas located in the fundus, corpus or antrum of the stomach respectively. With respect to T-stage, the overstaging of tumors was more common than understaging, especially in pT2b-carcinomas. The subgroup analysis of the 131 EGJ adenocarcinoma patients showed that the results obtained by EUS were slightly better in type I (distal esophageal cancer) than in type II and III cardia carcinomas (proximal gastric cancer).When comparing two observation periods (1992-1996 and 1997-2001), the accuracy of endoscopic ultrasound staging was very similar in both periods for T-category (51% vs 49%) and N-category (63% vs 64%) as well as for combined TN-staging (36% vs 35%) respectively. CONCLUSIONS: In clinical routine examinations of adenocarcinomas of the stomach and the distal esophagus, the accuracy of EUS is not as good as the excellent results in the past--mostly obtained under study conditions--may suggest.

[Delirium after vascular surgery interventions. Intermediate-term results of a prospective study]. / Durchgangssyndrome nach gefässchirurgischen Operationen. Zwischenergebnisse einer prospektiven Untersuchung.

INTRODUCTION: Postoperative delirium is a common psychic disturbance occurring acutely after various surgical procedures and typically presenting with a fluctuating course. These patients' recovery takes longer. In this study we analyze the incidence of postoperative delirium in patients undergoing vascular surgery and try to identify risk factors for its development. METHODS: Patients undergoing elective arterial operations were included. Their medical history, the specific vascular diagnosis and operation performed, the medication and laboratory data were monitored. Additionally the patients were preoperatively interviewed by a psychiatrist. Intraoperatively the drugs, infusions, possible transfusions, blood gases and pressures were monitored, as were the times of surgery and anesthesia. Postoperatively patients were seen daily by the psychiatrist and the surgeon for at least 7 days. Postoperative delirium was diagnosed according to DSM IV criteria, and mild, moderate and severe delirium were distinguished. RESULTS: Fifty-four patients entered the study. Twenty-one (38.9%) developed postoperative delirium (11 mild, 2 moderate, 8 severe). Patients with aortic operations developed delirium more frequently than those with non-aortic procedures(55.5 vs 22.2%, n = 27 each). Some preexisting diseases (hearing disturbance) increased the probability of postoperative delirium, while age was not identified as a risk factor. General psychopathological and depressive disturbances increased the likelihood of postoperative delirium. Patients who had a severe intraoperative course developed postoperative delirium more frequently. This was not seen in the absolute time of surgery or anesthesia nor in the intraoperative development of blood pressure or intraarterial gases, which did not differ between patients with and without postoperative delirium. More reliable parameters were an increased intraoperative need for crystalloid volume, intra- or postoperatively decreased hemoglobin values (Hb < 10 g/dl) and the development of acidosis that had to be treated. Patients with delirium had serious complications more often (8/21 = 38.1% vs 6/33 = 18.2%) and needed Intensive Care treatment longer (2.7 vs 2.1 days, only aortic surgery 3.2 vs 2.4 days). CONCLUSIONS: Postoperative delirium after vascular surgery is frequent. Patients undergoing aortic surgery, with specific concomitant medical disease, psychopathological disturbances and a severe intraoperative course, are at risk of developing postoperative delirium.