Biomedical subjects

M Suter

Publications and source records attributed to M Suter.

At least 109 records · Page 6Linked to original sources

PubMed1995

Accumulation of activated CD4+ lymphocytes in the lung of individuals infected with HIV accompanied by increased virus production in patients with secondary infections.

The lung is continuously exposed to infectious and non-infectious agents causing cell activation. Activated cells in the lung such as antigen-presenting cells which harbour HIV may favour this organ as a site for virus production. To test this hypothesis, cells from blood and bronchoalveolar lavage (BAL) of HIV-infected patients and healthy controls were obtained and the activation of the cells were analysed by measuring the expression of IL-2 receptor, HLA-DR and VLA-1. The HIV-infected individuals were subdivided into 'lung symptomatic' or 'lung asymptomatic' patients, depending on the presence or absence of secondary lung diseases besides HIV. All HIV-infected individuals demonstrated a decreased number of CD4+ lymphocytes in blood; however, normal numbers of these cells were found in BAL. The activation state of CD4+ and CD8+ T lymphocytes in blood and BAL was higher in lymphocytes from HIV-infected patients compared with controls. The activation state was highest in the lung symptomatic group. Lung symptomatic patients and lung asymptomatic patients with extrapulmonary infections had increased levels of free virus in plasma. Four out of four individuals without or with only low amounts of cell-free HIV in plasma belonged to the symptom-free subgroup. These results suggest that microorganisms other than HIV may promote viral replication via antigen-driven accumulation and activation of CD4+ cells in the lung or other organs, and thus may be responsible for the loss of helper T cells and the progression of the disease.

Bronchoalveolar Lavage Fluid↗

PubMed1995

[Interlocking nailing of the tibia].

Centromedullary nailing is a well-established method of treatment for diaphyseal long bone fractures. The indications have been broadened greatly since the introduction in 1974 of interlocking centromedullary nailing. The purpose of this paper is to review our first results with locked intramedullary nailing of the tibia. We report our experience with the first 19 cases of interlocking tibia nails (15 fractures, 1 delayed union, 2 pseudarthrosis, 1 osteotomy). On the extension table, the insertion of the nail and the placement of the interlocking screws did not cause any problem. In 3 cases, a proximal screw had to be removed within two weeks because of spontaneous displacement. Complications have been noticed in three patients (15.8%) (pulmonary embolism on day 1, and compartment syndrome two days later in one case, sciatic nerve neuroapraxia in the other two). The other patients have been mobilized 24 to 48 hours after surgery. 94% of the fractures were consolidated 4 months post-operatively, with no major deformation. Interlocking tibia nailing seems to be an attractive method in the treatment of certain fractures of the tibia. Early mobilisation and weight-bearing are provided. The indications, the technical aspects as well as the dangers of the method must be carefully respected in order to avoid complications and poor results.

Bone Nails↗

PubMed1995

Haemorrhage into the pancreatic duct (Hemosuccus pancreaticus): recognition and management.

OBJECTIVE: To highlight the clinical presentation, investigation and treatment of haemorrhage into the pancreatic duct. DESIGN: Retrospective study and review of publications. SETTING: University hospital, Switzerland. SUBJECTS: All 4 cases from 1972 to 1993. INTERVENTIONS: 2 Whipple procedures, 1 resection of the pancreatic head, 1 exploratory laparotomy. Radiological embolisation in one case. MAIN OUTCOME MEASURES: Cessation of haemorrhage and survival. RESULTS: The diagnosis was made preoperatively in three cases by gastroduodenoscopy and arteriography. Operation was the primary treatment in all patients and was effective with low morbidity and no mortality in three of them. Embolisation stopped the haemorrhage in the fourth patient, who was alcoholic and died of progressive liver insufficiency and variceal haemorrhage. CONCLUSIONS: There is no specific indication for haemorrhage into the pancreatic duct. The diagnosis is suggested by endoscopy (absence of a more common cause, or blood in the second part of the duodenum). Arteriography is essential to confirm the site of the bleeding and to attempt embolization. Operation is usually the definitive treatment.

Adult↗

PubMed1994

Antigenic surface of the bee venom allergen phospholipase A2. Structural functional analysis of human IgG4 antibodies reveals potential role in protection.

In the human immune response to the main bee venom allergen phospholipase A2 (PLA2), Abs of the IgG4 isotype are associated with protection. The antigenic sites of PLA2 that are recognized by two mAb of this isotype have been analyzed at the molecular level. The interaction of PLA2 with these two Abs has previously been shown to depend on the conformation of the Ag and to be sensitive to lysine modifications. Therefore, genetically engineered Ag displaying single point mutations of lysine residues were generated. Nine out of twelve surface-exposed lysine residues were substituted by glutamate or glutamine, and the effect of individual mutations on mAb binding was analyzed in the context of the folded Ag. Substitution of lysine at position 25 with either glutamate or glutamine completely abrogates binding to both mAb. All other mutants do not show a difference in binding when compared with wild-type Ag. Probing of sera from bee keepers with lysine 25 mutants reveals that a significant proportion of serum Abs of the IgG4 isotype display specificity for this epitope, suggesting that this represents a major B cell-antigenic site in hyperimmune individuals. We further found that both mAbs inhibit the catalytic activity of PLA2, a property that may account for the protective role of IgG4 Abs in hyperimmune individuals.

Allergens↗

PubMed1994

Human monoclonal or polyclonal antibodies recognize predominantly discontinuous epitopes on bee venom phospholipase A2.

BACKGROUND: Two hybridomas, which secrete human monoclonal antibodies of IgG4 isotype specific for the main bee venom antigen/allergen phospholipase A2, were generated. The antigenic determinants recognized by these antibodies were mapped and compared with the binding sites of murine monoclonal and human polyclonal antibodies raised against the same antigen. METHODS: Two hybridomas were developed by fusing heteromyelomas to Epstein-Barr virus immortalized B cells obtained from beekeepers. The cloned hybridomas were stable and secreted up to 40 mg/L of antibody into the culture supernatant. Phospholipase A2 specificity of the human monoclonal antibodies was confirmed by binding and inhibition ELISA and by Western blot analysis. Epitope mapping on phospholipase A2 was done with the PEPSCAN method and ELISA techniques. RESULTS: The epitopes recognized by the human monoclonal antibodies were shown to be discontinuous and did not contain the sugar residue. Similar results were obtained with polyclonal antibodies of IgG4 isotype (from beekeepers) specific for phospholipase A2, which could also inhibit the binding of the human monoclonal antibodies to phospholipase A2. In contrast, antigen binding of the human monoclonal antibodies could not be inhibited by murine monoclonal antibodies against bee venom phospholipase A2. CONCLUSIONS: The data indicate that the human monoclonal antibodies obtained are representative of a part of the polyclonal immune response to phospholipase A2 from beekeepers and may allow a more precise analysis of the humoral immune response to phospholipase A2 that is associated with protection.

Animals↗

PubMed1994

Diagnostic value of recombinant Aspergillus fumigatus allergen I/a for skin testing and serology.

BACKGROUND: We report a clinical study comparing the recombinant Aspergillus fumigatus allergen I/a (rAsp f I/a) to two commercial A. fumigatus extracts in skin prick tests, intradermal tests, and serologic assays. METHODS: Patients with allergic bronchopulmonary aspergillosis and A. fumigatus-allergic patients with asthma, and control subjects, including allergic patients with asthma without allergy to A. fumigatus and healthy subjects, were investigated. RESULTS: All patients with allergic bronchopulmonary aspergillosis (n = 15) reacted to skin prick tests with the commercial extracts, and eight were sensitized to rAsp f I/a. Of 10 patients with well-characterized A. fumigatus-allergic asthma nine showed positive skin prick test results to at least one of the commercial extracts, and five reacted to rAsp f I/a. There was a strong correlation between skin test reactivity to rAsp f I/a and rAsp f I/a-specific serum IgE as determined by an antigen-specific ELISA. The healthy control subjects (n = 7) and allergic patients with asthma without A. fumigatus allergy (n = 6) did not react in skin prick and intradermal tests to rAsp f I/a, nor did they have detectable amounts of rAsp f I/a-specific IgE. In addition, patients with allergic bronchopulmonary aspergillosis showed significant elevated levels of rAsp f I/a-specific IgG4 and IgG1 but no significant differences in rAsp f I/a-specific serum IgA levels when compared with the healthy control subjects. CONCLUSIONS: The data show that rAsp f I/a is a major allergen with biologic relevance in some A. fumigatus-allergic individuals as evaluated by skin prick tests, intradermal tests, or serologic methods. Furthermore, no discrepancies were observed between skin test results and rAsp f I/a-specific IgE. Hence the correlation between rAsp f I/a skin test results and serologic data indicates the potential of recombinant allergens for clinical applications and diagnosis of allergies.

Adult↗

PubMed1994

Lysine residues in bee venom phospholipase A2 are important for binding to human monoclonal or polyclonal antibodies of the IgG4 isotope.

Discontinuous antigenic sites on bee venom phospholipase A2 (PLA) have been mapped using human monoclonal antibodies or human polyclonal serum antibodies (hpAbs) of the IgG4 isotype from beekeepers or of the IgE isotype from individuals allergic to PLA. Lysine residues of PLA have been specifically modified by acetylation or acylation by treatment with citraconic anhydride of their epsilon-amino groups to analyze their role in antigen-antibody binding. After the modifications, the binding of PLA to the human monoclonal antibodies is lost, whereas the binding to IgG4 hpAbs is significantly decreased. In contrast, the effect on the binding of PLA to IgE hpAbs appears to be more heterogeneous. The data indicate the importance of lysine residues as being part of B cell epitopes in PLA-specific antibodies of the IgG4 isotype, but less so for those of the IgE isotype.

Acetylation↗

PubMed1994

[Volvulus of the small intestine as a cause of primary acute abdomen].

As a cause of small intestine occlusion, volvulus is often a consequence of a band or adhesions. Except in infants, it is rarely the primary cause of symptomatology. Between January 1976 and December 1992, 13 patients (7 women and 6 men, mean age of 56.8 years) were admitted in our department for an acute abdomen due to a spontaneous primary volvulus of the small bowel. Clinical examination and laboratory tests did not help in preoperative diagnosis. All patients underwent an explorative laparotomy. Six patients had had prior abdominal surgery but none of them presented adhesion or band. In 8 patients (62%), detorsion was sufficient. Resection of a segment of small bowel was necessary in 4 patients. Gangrenous of the entire bowel was observed in one patient who rapidly died. Two patients presented minor complications. One patient with Down syndrome died of bronchoaspiration. One patient has been reoperated on one year later for recurrence of the volvulus, and underwent a Noble procedure. We conclude that volvulus of the small bowel is a rare cause of acute abdomen that must be remembered. Early surgery is mandatory to reduce the risk of gangrene, which is known to double the mortality. Laparoscopy will be helpful in early diagnosis and therapy.

Abdomen, Acute↗

PubMed1994

[Therapeutic approach to para-esophageal hernia].

The charts of all the patients operated upon for paraesophageal hernia (HPO) were reviewed. 24 patients could be found between 1976 and 1992. The mean age was 64 years, with 15 men and 9 women. 15 patients had a pure HPO, whereas 9 had a mixed hernia (HPO and laxial hiatal hernia). 3 patients presented with acute symptoms, and 2 of them were operated on emergently. The remaining patients had elective surgery, consisting of reduction of the stomach (all cases), excision of the hernia sac (12), closure of the diaphragm (17) and gastropexy (8). There was no mortality. Due to the fact that acute complications occur in as much as 30-40% of the cases, elective surgery should be proposed to any patient with a known paraesophageal hernia if the operative risks are not prohibitive. A careful preoperative assessment including endoscopy and pH-manometry of the esophagus will provide arguments to add a antireflux procedure to the standard operation, which should include reduction of the stomach, resection of the sac, closure of the hiatal defect and gastropexy.

Aged↗

PubMed1994

[Endorectal ultrasound of rectal cancers].

Endorectal ultrasonography has become the preferred exam to assess the local extent of rectal cancers. From 1990 to 1992, we have examined 28 patients with a rectal cancer. The tumours were classified according to the TNM. The objective of this exam is to identify patients whose tumours have invaded the perirectal fat. These patients are first treated in our clinic by an accelerated hyperfractionated radiotherapy and then operated. The preoperative staging made with the endorectal ultrasound was then compared with the anatomopathologic staging. The depth of the invasion was assessed precisely in 78.5% of cases. The exam's sensitivity to detect the invasion of the perirectal fat was 96% and its specificity 75%. Lymph node involvement was accurately identified in 67.8% of cases with a sensitivity of 81% and a specificity of 50%. This short retrospective study confirms that endorectal ultrasonography is a highly accurate tool for the staging of rectal carcinoma prior to operation and hence to select the patients that can benefit from preoperative irradiation.

Adenocarcinoma↗

PubMed1994

[Thoracoscopic treatment of recurrent pneumothorax].

Spontaneous pneumothorax (PNO) is usually due to rupture of a small subpleural bleb into the pleural cavity and affects mainly young men. After simple drainage, recurrence occurs in about 50% of cases. The risk of recurrence increases after each new PNO. Secondary PNO complicates an underlying pulmonary disease, especially chronic obstructive pulmonary disease with emphysema. A new form of secondary PNO has emerged in the recent years in AIDS patients with pneumocystis carinii pneumonia. We have shifted to a thoracoscopic therapy of PNO since May 1991. 25 PNO in 24 patients (1 bilateral) have been treated since that time up to April 1993. 19 PNO were primary, whereas 6 were secondary, included 3 iatrogenic PNO. Resection of the leaking parenchymal area was performed in 20 patients, and parietal partial pleurectomy was done in 20 cases. In the remaining cases, fibrin glue was applied on the lesion and in 3 cases, chemical pleurodesis was attempted using silver nitrate or talc. 1 AIDS patient died of ARDS. 3 patients had recurrent PNO and had thoracotomy without complication. 21 patients did well. Partial PNO recurred in one of them 4 months later, and was treated by simple needle aspiration. Thoracoscopy is a useful method to treat recurrent or persistent spontaneous PNO. After only 25 cases, our success rate in primary PNO is 90%. There should be a learning curve. On the basis of our experience, we believe that recognition of the lesion and its resection as well as apical parietal pleurectomy are necessary to obtain good results and a low recurrence rate.

Adolescent↗

PubMed1994

[Current status of surgical transduodenal papillotomy].

The treatment of biliary lithiasis has changed during the past 20 years. Cholecystectomy remains the gold standard for cholelithiasis, but many options are available for calculi of the common bile duct. Among them are surgical open or laparoscopic choledochotomy, biliary-enteric anastomosis, transduodenal sphincterotomy (TDS), endoscopic sphincterotomy. With the aim to describe the current place of TDS, we reviewed the patients operated on in our department between 1976 and 1992. We found 78 patients with a mean age of 58 years (26-89 years). 34 (43%) of them had acute cholecystitis, with 26 being operated on urgently. 47 (60%) were jaundiced, 15 (19%) had pancreatitis and 12 (15%) had cholangitis before operation. Indications for TDS have been impacted stone or absence of progression of the contrast medium on intraoperative cholangiography in 71 patients (91%). 3 patients died (1 pulmonary embolism, 1 sepsis of pulmonary origin, 1 MOF syndrome complicating preoperative necrotizing pancreatitis). 30 patients (38%) had complications, of which 20 were directly related to TDS. Hemorrhage occurred in 4 cases, and resolved spontaneously without transfusion. Hyperamylasemia occurred in 17 instances, but clinical pancreatitis developed in only 1 case, with complete resolution. 1 duodenal fistula healed after conservative therapy. No death is attributable directly to TDS. Today, the importance of endoscopic sphincterotomy is increasing. This retrospective study shows that TDS, if performed with caution, does not increase the operative risks even in emergent operations. During surgical exploration of the common bile duct, TDS is indicated to remove an impacted stone, or as a bilio-enteric anastomosis if multiple stones are present with a thin common duct.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Display of biologically active proteins on the surface of filamentous phages: a cDNA cloning system for selection of functional gene products linked to the genetic information responsible for their production.

A cloning and expression system allowing display of functional cDNAs or other gene products on the surface of filamentous phage has been developed, exploiting the high-affinity interaction of the Jun and Fos leucine zippers. Gene jun was expressed from a lacZ promoter as a fusion protein with the viral coat protein, pIII, thereby being structurally incorporated into phage particles during infection with a helper phage. Using a second lacZ promoter of the phagemid, gene fos was co-expressed as an N-terminal fusion peptide to cDNA library gene products, so that the resulting Fos-fusion proteins could become associated with the Jun-decorated phage particles. To avoid interphage exchange of fos-cDNA fusion products, cysteines were engineered at the N- and C-termini of each of the leucine zippers, providing a covalent link of the cDNA gene product to the genetic instructions required for its production. Dissociation between phage and cDNA gene products was readily achieved using reducing agents. Phages displaying gene products covalently anchored on their surface via the modified leucine zippers can be selectively enriched 10(4)-10(6)-fold over nonspecific phages using antibodies. Thus, this cloning system allows rapid isolation of rare mRNA products from complex cDNA libraries by enrichment with appropriate ligands. This approach should allow the expression and cloning of dimeric proteins by cDNA shuffling.

Amino Acid Sequence↗

PubMed1993

Recombinant Aspergillus fumigatus allergen I/a (rAsp f I/a) in the diagnosis of Aspergillus related diseases.

A. fumigatus allergen I/a (rAsp f I/a) was produced in Escherichia coli, affinity purified by Ni(2+)-chelate chromatography and refolded. rAsp f I/a binds IgE of A. fumigatus-allergic individuals as shown by ELISA, dot blots and Western blots. In addition, rAsp I/a elicited positive immediate type I skin reactions in individuals allergic to A. fumigatus but not in control individuals. Hence, rAsp f I/a can be used as a standardized antigen/allergen for an improved serological and clinical diagnosis of A. fumigatus-associated diseases.

Allergens↗

PubMed1993

Antigen focusing by specific monomeric immunoglobulin E bound to CD23 on Epstein-Barr virus-transformed B cells.

Monomeric IgE bound to the low-affinity receptor for IgE (FcERII-CD23) on EBV-transformed human B cells selectively enhances binding of antigen and therefore presentation to specific T-cell clones. To demonstrate the role of monomeric IgE in antigen focusing, we have made use of a system consisting of human T-cell clones specific for Der-P1 (major allergen of the Dermathophagoides pteronyssinus), Der-P1 coupled to NIP (Der-P1-NIP), and the commercially available chimeric (human-murine) monoclonal IgE antibodies with specificity for the hapten NIP. We have found that monomeric IgE binds to CD23 and remains detectable on the surface of the B cells for a period of at least 16 hours at 37 degrees C. Pulsing of these IgE-anti-NIP (1 microgram/ml) treated B cells for 1 hour at 37 degrees C with low amounts (10 ng/ml) of Der-P1-NIP antigen allows the B cells to stimulate Der-P1-specific T cells. Even with IgE concentrations as low as 20 ng/ml, which were not detectable by immunofluorescence, we were able to induce a significant T-cell response. Furthermore, ongoing specific T-cell-B-cell interactions were not inhibited by the presence of high concentrations of nonspecific IgE molecules (incubated with up to 25 micrograms/ml) on the surface of the B cells. Our data confirm the hypothesis that IgE, bound by either CD23 or the high-affinity receptor for IgE, potentiates the immune response. Therefore, IgE may be seen as the fourth general mechanism for antigen capture by (nonspecific) antigen-presenting cells.

Animals↗

PubMed1993

[Hemorrhage through Wirsung's duct: rare form of upper gastrointestinal hemorrhage. A case report].

The case of a 41-year-old alcoholic patient who presented with massive upper gastrointestinal bleeding is reported. The diagnosis was established rapidly by endoscopy which revealed bleeding through the papilla of Vater. Selective angiography of the superior mesenteric artery opacified the pancreatic duct as well as the duodenum. CT scan showed signs of chronic pancreatitis. Because of the recurrence of bleeding and shock, an urgent operation was necessary and a Whipple procedure was performed. Recovery was complete. The clinical presentation, the etiology, the diagnostic modalities and the treatment of this particular condition are discussed. Usually, hemorrhage through the pancreatic duct presents as repeated episodes of upper gastrointestinal bleeding with no source found at endoscopy. The presence of chronic pancreatitis or of epigastric pain during bleeding should suggest the diagnosis. Upper gastrointestinal endoscopy and angiography are the principal diagnostic tools. Definitive treatment requires surgery, and resection in most of the cases.

Adult↗

PubMed1993

[Lesions of the small intestine and colon in blunt injuries of the abdomen].

Between 1976 and 1991, we observed lesions of the small bowel or colon in 39 patients having sustained blunt abdominal trauma. 70% of the patients presented with concomitant injuries. Except for 3 cases, all the patients presented with abdominal pain on admission. All the patients were operated on. The delay between admission and operation varied between a few minutes and 48 hours. Indication was hemoperitoneum, peritonitis or progressive abdominal pain. Overall morbidity is high, often related to associated disease. 4 patients died (mortality 10%), including 2 patients with isolated intestinal trauma who were operated on after 20 and 36 hours. Due to the lack of specific laboratory or X-ray test, we suggest a high index of suspicion for bowel lesions in blunt abdominal trauma, especially in unconscious patients. Close observation is mandatory. Indication for laparotomy must not be delayed if any doubt exists regarding the integrity of hollow viscus.

Abdominal Injuries↗

PubMed1993

[In situ venous grafts. Indications, technique and results. Prospective study of 26 consecutive cases].

The in situ saphenous vein bypass has been introduced in our department since 1989. A total of 26 bypasses in 22 patients have been followed prospectively. Indications for revascularisation have been severe arterial insufficiency in 73% of the cases (stage III or IV). With the exception of one postoperative death (myocardial infarction), all the patients have recovered uneventfully, with a regression to stage I. No amputation has been necessary. Morbidity has been 30%, with mainly minor local complications. The primary patency rate is 83% at one year and 78% after 2 and 3 years, whereas the secondary patency rate is 91% at one year, and remains constant thereafter up to 3 years. Considering our results and those from the literature, we believe that the in situ technique is very valuable, especially for below-knee vascular reconstruction. Technical difficulties of the method are analysed.

Adult↗