Biomedical subjects

Ernst Klar

Publications and source records attributed to Ernst Klar.

39 records · Page 3Linked to original sources

PubMed2001

Detection of disseminated medullary thyroid carcinoma cells in cervical lymph nodes by cytokeratin 20 reverse transcription-polymerase chain reaction.

Local recurrence in differentiated and medullary thyroid carcinoma develops frequently from metastatic infiltration of cervical lymph nodes. Despite an aggressive surgical approach, postoperative calcitonin levels as biochemical evidence for residual cancer cells remain often elevated in patients with medullary thyroid carcinoma. In the present study, we compared the detection rates of disseminated medullary thyroid carcinoma cells in cervical lymph nodes by histopathology with reverse transcription-polymerase chain reaction (RT-PCR) amplification of cytokeratin 20 (CK20) transcripts as a more sensitive but still specific molecular parameter for residual thyroid cancer cells. Forty-two cervical lymph nodes obtained from 7 patients with CK20positive medullary thyroid carcinomas were cut into two halves, one used for conventional histology, the other subjected to RNA extraction and subsequent amplification of cytokeratin 20 transcripts. Matching results for CK20 RT-PCR and histopathology were found in 74% (31/42)of the examined lymph nodes (52% positive results, 48% negative results). Positive CK20 RT-PCR pointed to residual thyroid carcinoma cells in another 19% (8/42), in which no thyroid carcinoma cells were identified by histopathology. Histology and immunohistochemistry,however, identified tumor cells in 7% (3/42) of the analyzed lymph nodes, from which no CK20 transcript could be amplified (false-negative results). These data suggest that CK20 RT-PCR might be more sensitive to detect nodal involvement of CK20 positive medullary thyroid carcinomas than conventional histopathology. In combination with histology, it might help to identify patients with residual disease after surgery.

Adenocarcinoma, Follicular↗

PubMedDate not supplied

Reduction in mortality with delayed surgical therapy of severe pancreatitis.

The indications for surgery in acute pancreatitis have changed significantly in the past two decades. Medical charts of patients with acute pancreatitis treated at our institution were analyzed to assess the effects of changes in surgical treatment on patient outcomes. A total of 136 patients with radiologically defined severe pancreatitis were primarily treated or referred to our institution between 1980 and 1997. Severity of the disease (Ranson score), indications for surgical intervention, timing of surgery, and mortality rates were compared during three study periods: 1980 to 1985 (period I), 1986 to 1990 (period II), and 1991 to 1997 (period III). In period I patients underwent exploratory laparotomy if their clinical status did not improve markedly within 72 hours of admission to the hospital, whereas during period II surgery was reserved for patients who had secondary organ failure together with pancreatic necrosis seen on CT scan. During period III the aim was to operate as late as possible in the presence of pancreatic necrosis or when infected necrosis was suspected. The policy of limiting the indications for surgery resulted in a decrease in surgically treated patients from 68% to 33% (P < 0.001). Likewise, surgical intervention was performed later. In period I, 73% of operations were performed within 72 hours of admission, compared to 32% in period III (P = 0.008). The mortality rate for patients who underwent early surgery (within 72 hours) was higher than for those who underwent late surgical exploration of the abdomen (P = 0.02). Overall, the mortality rate for patients with severe pancreatitis was reduced from 39% to 12% (P = 0.003). Mortality among patients treated nonoperatively did not change significantly. The present study supports the policy of delayed surgery in severe acute pancreatitis. Early surgical intervention often results in unnecessary procedures with an increase in the number of deaths. Whenever possible, prolonged observation allows selection of patients who are likely to benefit from delayed surgery or nonoperative treatment.

Acute Disease↗

PubMedDate not supplied

Limits of Couinaud's liver segment classification: a quantitative computer-based three-dimensional analysis.

PURPOSE: Traditionally, liver surgery relies on Couinaud's liver segment classification. As the position and shape of these segments are variable and their borders are hidden within the homogeneous liver mass, the accuracy of segment identification methods needs computer-aided reevaluation. METHOD: The segmental liver anatomy of 23 patients receiving diagnostic helical CT scans because of suspected intrahepatic lesion was analyzed with the aid of a computer-based operation-planning system. We compared the standard Couinaud classification, which depends particularly on the main stems of portal and hepatic veins, with a method that calculates the segment borders by analyzing the complete portal venous tree. Volume, shape, and position of the liver segments found by each method were compared. RESULTS: With reference to the portal vein-based method, segmental volumes were overestimated by the classic Couinaud method by up to 24% and underestimated to 13%. Volumes of Couinaud segments 4a, 7, and 8 were generally larger compared with those obtained by the portal vein-based method, whereas segments 3 and 6 were smaller. Gross variations were found in segments 5, 7, and 8. When shape and position were considered, poor correlation was found for five segments (median kappa = 0.35-0.45). Only segments 2, 7, and 8 had kappa values clearly above 0.45 in the majority of cases. The plane that divides the two hemilivers along the middle hepatic vein and the border between the left sector (segments 2 and 3) and the medial sector (4a and 4b) were found in both methods with very good conformity (kappa > 0.75). CONCLUSION: Couinaud's method of dividing the liver into eight autonomous liver segments has to be accepted as a good approximation. Nevertheless, the volume, position, and shape of these segments and their segmental borders show significant variability.

Adult↗