N-glycosylation engineering of biopharmaceutical expression systems.

N-glycosylation, the enzymatic coupling of oligosaccharides to specific asparagine residues of nascent polypeptide chains, is one of the most widespread post-translational modifications. Following transfer of an N-glycan precursor in the ER, this structure is further modified by a number of glycosidases and glyco-syltransferases in the ER and the Golgi complex. The processing reactions occurring in the ER are highly conserved between lower and higher eukaryotes. In contrast, the reactions that take place in the Golgi complex are species- and cell type-specific. Due to its non-template driven nature, glycoproteins typically occur as a mixture of glycoforms. Since N-glycans influence circulation half-life, tissue distribution, and biological activity each glycoform has its own pharmacokinetic, pharmacodynamic and efficacy profile. Moreover, modification of glycoproteins with non-human oligosaccharides can result in undesired immunogenicity. Therefore, engineering of the N-glycosylation pathway of most currently used heterologous protein expression systems (bacteria, mammalian cells, insect cells, yeasts and plants) is actively pursued by several academic and industrial laboratories. These research efforts are in the first place directed at humanizing the N-glycosylation pathway and eliminating immunogenic glycotopes. Moreover, one wants to establish new structure-function relationships of different glycoforms, which helps to decreasing the complexity of the N-glycan repertoire towards one defined N-glycan structure. In this review, we discuss the most important recent milestones in the glycoengineering field.

[A men with a Salmonella dublin-infected aneurysm of the abdominal aorta]. / Een man met een door Salmonella dublin geïnfecteerd abdominaal aneurysma aortae.

A 71-year-old male was diagnosed with a Salmonella dublin infection. He presented with abdominal pain with no diarrhoea, and sepsis, and was found to have an infected aneurysm of the infrarenal abdominal aorta. He was treated surgically with resection of the aneurysm and implantation of an extra-anatomic axillobifemoral bypass, followed by long-term antibiotic treatment. Nine months after the primary treatment, the patient died as a result of rupture of the aortic stump. S. dublin-infected aneurysm of the abdominal aorta is a rare condition with high mortality. Human S. dublin infections are associated with the consumption of unpasteurised dairy products from infected animals.

Traumatic pseudoaneurysm of the superficial temporal artery.

This paper describes, by case histories and a literature review, the cause, diagnosis and therapy of pseudoaneurysm of the superficial temporal artery. Two patients with a traumatic pseudoaneurysm of the superficial temporal artery were examined by physical examination and histology of the excised lesions. Blunt injury caused a histologically proved pseudoaneurysm in two reported cases. A total of 12 additional reports of pseudoaneurysm of the superficial temporal artery were found in the literature. Pseudoaneurysm of the superficial temporal artery is an uncommon complication of blunt head injury. Symptoms are limited and diagnosis can be made by noninvasive means. A high suspicion level for arterial injury and sufficient follow-up of patients is necessary for the detection of arterial injury.

[Simple ligation superior to inversion of the appendiceal stump; a prospective randomized study]. / Simpel onderbinden beter dan instulpen van de appendixstomp; een prospectief gerandomiseerd onderzoek.

OBJECTIVE: To compare two methods of treatment of the appendix stump after appendectomy for acute appendicitis. DESIGN: A prospective randomised trial of 134 consecutive appendectomies in which the appendix stump was either simply ligated or ligated and doubly invaginated. SETTING: Department of General Surgery, St Joseph Hospital, Veldhoven, the Netherlands. PATIENTS AND METHODS: During a period of 15 months all patients in whom an appendectomy for acute appendicitis was performed were allocated at random to the two groups. The following data were recorded: age, sex, histological diagnosis, hospital stay and occurrence of complications. All patients were followed until 6 months after the operation. The data were analysed statistically with the chi-square-test and the Mann-Whitney test. P less than 0.05 was considered significant. RESULTS: The appendix stump was ligated in 79 patients and invaginated in 55. Both groups were similar with respect to age, sex, degree of appendiceal inflammation, antibiotic treatment and hospital stay. There were significantly more wound infections in the 'invagination' group (p = 0.017). The other complications showed no statistical intergroup difference. CONCLUSION: Simple ligation facilitates and shortens appendectomy. It is a safe procedure, preventing deformation of the caecal wall and possibly reducing the risk of postoperative ileus due to adhesions. We therefore recommend simple ligation as the standard procedure at appendectomy.

[Medium-long-term good results of vertical gastroplasty in the treatment of morbid obesity]. / Goede resultaten op middellange termijn van verticale maagverdeling ter behandeling van overmatige vetzucht.

To determine the long-term results of the surgical treatment of patients with morbid obesity, a retrospective analysis of the patients in whom a vertical banded gastroplasty according to Mason was performed in the period 1982-1990 was carried out in the department of General Surgery, St. Joseph Hospital, Veldhoven, the Netherlands. In a series of 20 patients (4 men and 16 women) with a mean age of 32 (17-53) years who were eligible for treatment according to international criteria surgery was performed. The preoperative weight averaged 124 (94-207) kg and the mean preoperative excess weight was 60 (37-132) kg. Immediate postoperative complications occurred in 5 and late complications in 7 patients. Revision for technical complications was necessary in 2 patients. Twelve patients were followed up for more than 4 years. The mean weight loss after 4 years was 37 (18-89) kg, which was 28 (18-43) per cent of the mean preoperative weight and 62 (31-89) per cent of the mean preoperative excess weight. The 4-year results were unsatisfactory (less than 50 percent excess weight loss) in 3 of the 12 patients. It is concluded that vertical banded gastroplasty in our hands seems a relatively safe and effective surgical method of achieving sustained weight loss in most patients.

Obstetric fecal incontinence. Role of pelvic floor denervation and results of delayed sphincter repair.

During the last five years, 37 patients with fecal incontinence because of childbirth have been investigated. Ages varied from 22 to 62 years and duration of symptoms from 0.3 to 26 years. Anal manometry was performed in all patients and electromyography was performed in 24 patients. Thirty patients underwent delayed sphincter repair. In all patients, a dehiscence was found anteriorly, bridged by scar tissue. Continence was restored in 25 patients (83 percent). Electromyography was performed postoperatively in patients who remained incontinent and who demonstrated severe denervation. All these patients had undergone previous sphincter repair. In seven patients, there were no signs of obstetric injury. Electromyography demonstrated severe denervation, but sphincter mapping did not demonstrate muscle discontinuity. Continence improved in four patients within one year as a result of reinnervation demonstrated by electromyography. The authors conclude that fecal incontinence after childbirth may be due to either obstetric rupture or denervation. Both disorders may coexist. Delayed sphincter repair gives excellent results provided that denervation is not present. Preoperative assessment with electromyography is mandatory.

Role of gastroenterostomy in the palliative surgical treatment of pancreatic cancer.

The records of 72 consecutive patients with unresectable pancreatic cancer treated between 1974 and 1986 were evaluated to determine whether gastroenterostomy should be performed on a routine basis at initial intervention or on a therapeutic basis. Fourteen patients underwent an explorative laparotomy, 41 patients underwent biliary bypass, and 17 patients required biliary bypass and therapeutic gastroenterostomy at initial laparotomy. The mortality and morbidity rates in this last group were 18 and 59%, respectively. The most common complication was delayed gastric emptying (29%). Of the 37% of patients who required gastroenterostomy after initial biliary bypass, the mortality rate was 50% and delayed gastric emptying occurred in 57%. The mean survival after biliary bypass was 9.4 months while survival after therapeutic gastroenterostomy averaged 4.2 months. These findings suggest that gastroenterostomy should be performed on a prophylactic basis at initial intervention, unless a limited survival is expected.

Postanal repair restores anatomy rather than function.

The effects of postnatal repair on internal and external sphincter function has been assessed by comparing preoperative and postoperative manometric results in 39 patients with neurogenic fecal incontinence. Postanal repair was effective in 70 percent. The urge to defecate was restored in 70 percent, the ability to retain feces in 45 percent. The procedure caused an increase in squeeze pressure (P = .001), but clinical results were not related absolutely to improvement of external sphincter function, which remained within limits of fecal incontinence in most cases. The procedure restores anatomy rather than function. The influence of the procedure on resting pressure was not statistically significant (P = .4).

[Fecal incontinence following obstetrical injury; significance of damaged pelvic floor innervation and results of surgical treatment]. / Incontinentie voor faeces na obstetrisch letsel; betekenis van beschadigde bekkenbodeminnervatie en resultaten van chirurgische behandeling.

During the last 5 years 33 patients with faecal incontinence due to childbirth were investigated. Ages varied from 23 to 61 and duration of symptoms from 0.3 to 25 years. Anal manometry was performed in all patients and electromyography was performed in 21 cases. Twenty-seven patients underwent delayed sphincter repair. Continence was restored in 21 (81%). Post-operatively performed EMG in the patients who remained incontinent demonstrated severe denervation but sphincter mapping did not demonstrate muscle discontinuity. Continence improved in three patients within one year as results of reinnervation. Faecal incontinence after childbirth may be due to either obstetric rupture or denervation. Both disorders may coexist. Sphincter repair gives excellent results provided denervation is not present. Preoperative assessment by EMG is mandatory.