Production of very-high-amylose potato starch by inhibition of SBE A and B.

High-amylose starch is in great demand by the starch industry for its unique functional properties. However, very few high-amylose crop varieties are commercially available. In this paper we describe the generation of very-high-amylose potato starch by genetic modification. We achieved this by simultaneously inhibiting two isoforms of starch branching enzyme to below 1% of the wild-type activities. Starch granule morphology and composition were noticeably altered. Normal, high-molecular-weight amylopectin was absent, whereas the amylose content was increased to levels comparable to the highest commercially available maize starches. In addition, the phosphorus content of the starch was increased more than fivefold. This unique starch, with its high amylose, low amylopectin, and high phosphorus levels, offers novel properties for food and industrial applications.

The complications of pancreatectomy.

This paper analyses the early postoperative complications after 285 pancreaticoduodenectomies performed during the past 15 years in the Surgical University Clinic, Mannheim. There were 235 partial (Whipple) and 52 total pancreatectomies performed for pancreatic and periampullary tumors (181 patients) and complicated chronic pancreatitis (104 patients). A total of 92 complications requiring relaparotomy in 42 patients ended fatally in nine patients. The overall operative and hospital mortality rate was 3.1%. The most frequent and most dangerous were complications at or around the pancreaticojejunal anastomosis, which occurred 25 times with five deaths. Postoperative hemorrhage was seen in 16 patients; endoscopic treatment in four patients and operation in 12 patients was successful in stopping the bleeding in all but one patient. Eight biliary fistulae either ceased spontaneously (3 patients) or after operative reintervention (5 patients) without any mortality. Control of these complications depends on four lines of approach: (1) before operation: optimal preparation of the jaundiced patient including endoscopic transpapillary decompression of the common duct; (2) during operation: a meticulous and standardized technique is mandatory; (3) after operation: continuous observation in the surgical intensive care unit is essential for the timely detection of possible complications; and (4) early reintervention can salvage the great majority of these patients with deleterious complications.

[Multivisceral and extended resection in pancreatic cancer]. / Multiviszerale und erweiterte Resektionen beim Pankreaskarzinom.

Out of 303 pancreatoduodenectomies performed for carcinoma in the past 19 years, 100 patients required a multivisceral or (in 39 cases) a regional pancreatectomy. Although the operative and hospital mortality for these extended resections was only 2%, long-term survival (only 1 patient survived more than 5 years) was inferior to conventional radical pancreatoduodenectomy with a 25% 5-year survival rate.

Thoracic spinal stenosis: diagnostic and treatment challenges.

Thoracic stenosis may be defined by a narrowing of the anteroposterior (AP) diameter of the thoracic spinal canal to < 10 mm. Primary thoracic stenosis, documented when myelography is carried beyond the thoracolumbar junction into the upper thoracic canal, is most frequently associated with lumbar stenosis, whereas secondary stenosis, attributed to endocrinopathies and systemic diseases, more typically involves the entire spinal canal. Recognition of the presence of primary or secondary thoracic stenosis and the entire extent of attendant disease in the adjacent cervical or lumbar regions is essential to proper surgical management. Nine cases of primary and one instance of secondary thoracic spinal stenosis were reviewed. Seven of nine patients with primary thoracic stenosis had accompanying lumbar involvement, whereas one patient with secondary stenosis attributed to acromegaly had cervical, thoracic, and lumbar stenosis.

[The Whipple partial duodenopancreatectomy--its value in the treatment of chronic pancreatitis]. / Die partielle Duodenopankreatektomie nach Whipple--Stellenwert in der Behandlung der chronischen Pankreatitis.

The surgical treatment of chronic pancreatitis is indicated only in the complicated disease. The aim is mainly the treatment of pain, of mechanical obstacles and to exclude suspicion of cancer. Between October 1972 and January 1993 713 patients with chronic pancreatitis were treated at the Surgical University Hospital in Mannheim. In 40% of the patients conservative treatment was continued or intensified. Only in 123 patients a Whipple operation was performed. The leading symptom was pain in these patients. We saw postoperative surgical complications in 14 patients (11.4%). One of them died due to an operative leak (0.8%). Late results are based on a median follow up of 4.8 years and showed a complete or substantial pain relief in 94%. 66% went back to work. 77% gained weight with an average of more than 10 kg. The rate of postoperative endocrine insufficiency was 10% (total 40%), of exocrine insufficiency 26 (total 51%). Late mortality was 11% and mostly caused by continued alcoholic abuse. Based on these results, the Whipple operation seems to be the best standardized method for surgery of the complicated chronic pancreatitis within the head of the pancreas.

Survival after pancreatoduodenectomy. 118 consecutive resections without an operative mortality.

Twenty-one years ago, Howard published a paper entitled "Forty-one Consecutive Whipple Resections Without an Operative Mortality." That paper stimulated the present analysis of the last 118 consecutive pancreatoduodenectomies (107 Whipple and 11 total resections) performed at the Surgical University Clinic Mannheim from November 1985 to the present day with no deaths. Ninety-one resections were performed for neoplasms and 27 were for complicated chronic pancreatitis. The preoperative evaluation, operative technique, and postoperative care of these cases is discussed in detail and compared to the experience of Howard. While there was general agreement on operative technique, there were differences concerning preoperative evaluation (modern imaging methods) and postoperative care (simplification). In this series 21 postoperative complications required seven relaparotomies. Long-term survival after resection for carcinoma was analyzed for 133 consecutive patients who were shown to have true ductal adenocarcinoma. In 76 patients, who had radical (R0-) resections, the actuarial 5-year-survival rate was 36%. In 44 patients, whose R0-resections for pancreatic cancer occurred more than 5 years ago, the actual survival rate was 25%.

Resection of pancreatic cancer--surgical achievements.

INTRODUCTION: Looking back at the initially dismal record for pancreatic cancer surgery - Whipple himself felt that a 30-35% mortality was justifiable (!) - significant progress has been made. PROGRESS: The operative mortality has fallen below 5% and the serious complications of pancretic resections such as leaks and haemorrhage have been reduced to some 10% and we are better equipped to deal with these if they occur. The 5-year-survival of patients in whom pancreatic cancer was amenable to an R0-resection has risen to 30%. These are the surgical achievements using the standard Kausch-Whipple technique alone. There has been no improvement in these results, either by increasing radicality (regional pancreatectomy) or by reducing it (pylorus-preserving pancreatoduodenectomy). The same can be said of all other modalities of oncological treatment that have been tried so far: adjuvant radiochemotherapy, regional chemotherapy, hormonal or genetic manipulations. PERSPECTIVE: This does not mean that we should reduce efforts at improving early detection of the disease and unravelling its complex molecular biology. On the contrary, the results of surgery alone in spite of all improvements seem to have reached a plateau that gives little cause for complacency.

Resection for adenocarcinoma of the body and tail of the pancreas.

Adenocarcinoma of the pancreatic body and tail often presents late and is widely regarded as incurable by surgical resection; long-term survivors are rare. Thirteen patients underwent left resection (n = 7) or total pancreatectomy (n = 6) in a consecutive series of 105 patients with carcinoma of the body or tail of the pancreas. Comparison was made with 17 patients with locally advanced or metastatic disease. Preoperative computed tomography predicted irresectable disease when a large perivascular lymph node mass was demonstrated. Preoperative angiography predicted irresectable disease when there was encasement or obliteration of the coeliac axis or its major branches, or of the superior mesenteric artery or vein. Splenic vessel involvement was sometimes compatible with resection. After resection, median survival was 13 (range 3-50) months, with a minimum follow-up of 2 years. Five patients survived more than 2 years, and three are still alive 30, 43 and 50 months after resection. Resection of carcinoma of the body or tail of the pancreas was possible in 12 per cent of patients and long-term survival was observed in some of these.

[Results of surgical therapy of early stomach cancer]. / Ergebnisse der chirurgischen Therapie beim Magenfrühkarzinom.

Between 1972 and 1993 232 patients with early gastric cancer have been resected at the Surgical University Hospital of Mannheim. At the time of surgery 9.9% of the patients had lymph node involvement, 2 of them had distant metastases. In 59.9% of the cases (n = 138) a subtotal distal gastric resection, in 34.1% (n = 79) a total gastrectomy and in 6.4% (n = 15) a proximal or an atypical resection were performed. Following distal resection and total gastrectomy a radical lymphadenectomy of the compartments I and II was performed. The hospital lethality was 5.2%, the morbidity 18.1%. There were no statistical significant differences between the different surgical methods. The cumulative-5-year-survival rate was 80% without any statistically significant differences between the surgical methods and the histological types according to the Japanese classification of early gastric cancer.

[Is diagnostic laparoscopy a reliable addition to preoperative staging of pancreatic carcinoma?]. / Ist die diagnostische Laparoskopie eine sinnvolle Ergänzung des präoperativen Stagings beim Pankreaskarzinom?

Over the last decade several authors proposed adopting diagnostic laparoscopy as an early diagnostic routine method in the staging of pancreatic carcinoma to prevent exploratory laparotomy. In our hospital only 11.6% of all patients who underwent explorative laparotomy would have benefitted from diagnostic laparoscopy. Therefore, we do not recommend diagnostic laparoscopy as a routine method to assess resectability of pancreatic carcinoma?

Completion pancreatectomy for surgical complications after pancreaticoduodenectomy.

Significant complications continue to occur in a minority of patients undergoing pancreaticoduodenectomy; these frequently have fatal consequences. Analysis of 458 patients undergoing the Whipple procedure in this institution from 1972 to 1994 revealed that 16 patients with malignant periampullary tumours (ampullary, eight; pancreatic, seven; bile duct, one), and one patient with chronic pancreatitis subsequently required completion pancreatectomy. Postoperative difficulties after pancreaticoduodenectomy and indications for re-exploration were multifactorial: leakage (n = 8), pancreatitis (n = 7), bleeding (n = 1), and a delayed report of cancer at the margin of the pancreatic transection (n = 1). Completion pancreatectomy was often difficult (mean operating time 2.7 h, mean estimated blood loss 1897 ml). There was considerable significant postoperative morbidity (41 per cent) and mortality (24 per cent) after completion pancreatectomy. Patients who survived completion pancreatectomy lived a mean of nearly 4 years (range 4 months to 9.7 years, median 2.6 years). Tumour recurrence led to death in ten of 13 patients. Three patients remain alive and free of recurrence each more than 8 years after resection. Re-exploration and subsequent completion pancreatectomy after pancreaticoduodenectomy is rarely necessary, but if clinical manifestations occur secondary to failure of the pancreaticojejunostomy, early surgical intervention may maximize survival.

The transketolase gene family of the resurrection plant Craterostigma plantagineum: differential expression during the rehydration phase.

Transketolases, key enzymes of the reductive and oxidative pentose phosphate pathways, are responsible for the synthesis of sugar phosphate intermediates. Here we report the first molecular analysis of transketolase genes from plants. Three distinct classes of transketolase-encoding cDNA clones were isolated from the desiccation-tolerant resurrection plant Craterostigma plantagineum. One class represented by the transcript tkt3 is constitutively expressed in leaves and roots under all physiological conditions tested. By biochemical analysis and protein sequencing of purified transketolase, it was shown that tkt3 is expressed in three enzymatically active isoforms. An intriguing discovery was that accumulation of the two other transketolase transcripts, tkt7 and tkt10, is preferentially associated with the rehydration process of the desiccated plant; whereas tkt10 is only expressed in leaves, tkt7 was detected in leaves and roots. This observation suggests a possible role for these transketolases in the conversion of sugars, which are a major phenomenon in the rehydration process. Despite an abundant level of tkt7 and tkt10 transcripts in rehydrating leaves, proteins could not be isolated. This is due in part to a translational control mechanism acting on the loading of mRNAs to polysomes.

Determination of lectin characteristics by a novel agglutination technique.

A technique generally applicable for the determination of lectin characteristics is described. A sensitive light transmission/scattering method was adapted for the determination of lectin levels and lectin activity. Applying this procedure Geodia cydonium lectin-mediated agglutination was studied in an agglutimeter device using erythrocytes and even T-lymphocytes. In the Geodia lectin/T-lymphocyte system chosen, (i) a lectin concentration as low as 0.57 micrograms/ml could be measured accurately, (ii) the observed cell agglutination velocity constant with a maximal value of 0.75 min-1 was calculated, and (iii) the size of the agglutinates at a given lectin concentration and time period was estimated. The Geodia lectin activity was determined in parallel also in the erythrocyte system. Here, compared to the lectin/T-lymphocyte system the agglutination efficiency of the Geodia lectin-mediated agglutination was more than 10-fold higher and the lowest detectable lectin concentration was 0.06 micrograms/ml. Compared to the hemagglutination assay the lectin/erythrocyte system turns out to be more sensitive and to give much more information on agglutination behavior; this conclusion is supported by additional data using a second lectin isolated from Pellina semitubulosa. The superiority of the agglutination method described here over other known methods must be seen in its accuracy; moreover more lectin characteristics can be determined.

[Adrenal incidentaloma]. / Adrenale Inzidentalome.

Asymptomatic adrenal tumors are discovered more and more frequently with improving quality of diagnostic imaging. Treatment of these tumors, described as incidentalomas is controversial and depends on the one hand on the size of the tumor and on the other hand on morphological appearance in diagnostic imaging. In the literature a tumor size over 3 cm is in general regarded as an indication for operation, based on findings of Copeland et al. where the size of the tumor was correlated with malignancy. In the Department of Surgery in Mannheim 28 operations on adrenal incidentalomas have been performed between 1973-1993. In three patients a carcinoma was found. Four of the removed tumors each of them benign had a diameter smaller than three centimeters. An operation seems to be justified under certain conditions, even in small tumors, because potentially malignant tumors can undergo early and radical surgery. A general recommendation for treatment of the above mentioned tumors, depending only on size and morphology in diagnostic imaging, seems to be difficult. The decision for surgical therapy needs to be evaluated individually for every patient.

[Postoperative follow-up in patients with partial Whipple duodenopancreatectomy for chronic pancreatitis]. / Postoperative Verlaufskontrolle bei Patienten mit partieller Duodenopankreatektomie nach Whipple wegen chronischer Pankreatitis.

BACKGROUND AND AIM: Physicians and surgeons essentially agree today that chronic pancreatitis must primarily be treated conservatively. The aim of surgery in chronic pancreatitis is the treatment of symptoms. Surgical treatment cannot be a causal therapy for chronic pancreatitis. If surgery is indicated at all. Whipple's operation is considered to be the gold standard. PATIENTS AND METHODS: Between 1973 and 1992, out of a total of 700 patients referred to the surgery University Department in Mannheim with the express purpose of having an operation for chronic pancreatitis, duodenopancreatectomy (Whipple's operation) was performed in 110 cases. 58 of these patients were followed up postoperatively and the results have been compared with preoperative findings. RESULTS: All patients returned to full or only slightly impaired activity. 60% took up work again, 40% retired after the operation with a mean age of 49 years. 38 patients (66%) were totally free of pain, 13 patients (22%) had less pain than preoperatively and only seven (12%) often need analgesics postoperatively because of abdominal pain. Preoperatively there has been a history of long-standing excessive alcohol use in 32 (55%) patients, in the postoperative period there was a significant reduction to only three (5%) patients. 40 patients clinically examined were in a sufficient nutritional condition. Exocrine function of the pancreas (stool chymotrypsin and fluorescein dilaurate test) showed an insufficiency in 20 (71%) of 28 cases. The preoperative exocrine function of the pancreas was not examined in most cases. Examination of endocrine function showed diabetes mellitus treated with insulin occurring preoperatively in six (10%) patients and in 21 (36%) patients postoperatively. CONCLUSION: As chronic pancreatitis very often is concentrated in the head of the pancreas, Whipple's operation seems to be a good procedure for pain relief and concerning late results of life quality and socioeconomic situation.

A minor form of starch branching enzyme in potato (Solanum tuberosum L.) tubers has a major effect on starch structure: cloning and characterisation of multiple forms of SBE A.

Full length cDNAs encoding a second starch branching enzyme (SBE A) isoform have been isolated from potato tubers. The predicted protein has a molecular mass of 101 kDa including a transit peptide of 48 amino acids. Multiple forms of the SBE A gene exist which differ mainly in the length of a polyglutamic acid repeat at the C-terminus of the protein. Expression of the mature protein in Escherichia coli demonstrates that the gene encodes an active SBE. Northern analysis demonstrates that SBE A mRNA is expressed at very low levels in tubers but is the predominant isoform in leaves. This expression pattern was confirmed by Western analysis using isoform specific polyclonal antibodies raised against E. coli expressed SBE A. SBE A protein is found predominantly in the soluble phase of tuber extracts, indicating a stromal location within the plastid. Transgenic potato plants expressing an antisense SBE A RNA were generated in which almost complete reductions in SBE A were observed. SBE activity in the leaves of these plants was severely reduced, but tuber activity was largely unaffected. Even so, the composition and structure of tuber starch from these plants was greatly altered. The proportion of linear chains was not significantly increased but the average chain length of amylopectin was greater, resulting in an increase in apparent amylose content as judged by iodine binding. In addition, the starch had much higher levels of phosphorous.