Molecular typing shows a high level of HLA class I incompatibility in serologically well matched donor/patient pairs: implications for unrelated bone marrow donor selection

In comparison with HLA-matched sibling bone marrow transplants, unrelated donor transplants are associated with increased graft-versus-host disease and graft failure. This is likely in part due to HLA incompatibilities not identified by current matching strategies. High resolution DNA-based typing methods for HLA class II loci have improved donor selection and treatment outcome in unrelated donor bone marrow transplantation. By using DNA-based typing methods for HLA-A and -B on a cohort of 100 potential bone marrow donor/patient pairs, we find that serological typing for HLA class I is limited in its ability to identify incompatibilities in unrelated pairs. Furthermore, the incompatibilities identified are associated with the presence at high frequency of alloreactive cytotoxic T-lymphocyte precursors. DNA typing also indicates that HLA-C mismatches are common in HLA-A and -B serologically matched pairs. Such mismatches appear to be significantly less immunogenic with respect to cytotoxic T-lymphocyte recognition, but are expected to influence natural killer cell activity. Thus, improved resolution of HLA class I shows many previously undisclosed mismatches that appear to be immunologically functional. Use of high resolution typing methods in routine matching is expected to improve unrelated donor selection and transplant outcome.     

Cloning of aas, a gene encoding a Staphylococcus saprophyticus surface protein with adhesive and autolytic properties

A gene encoding a novel cell wall-associated protein of Staphylococcus saprophyticus that binds fibronectin and to sheep erythrocytes has been cloned and sequenced. The 4392 bp open reading frame codes for an amino acid sequence that is quite similar to the Atl, an autolysin, of Staphylococcus aureus and to the AtlE of S. epidermidis. The two regions of most pronounced homology code for an N-acetyl-muramyl-L-alanine amidase and for an endo-beta-N-acetyl-D-glucosaminidase. The cloned protein lysed cells of S. saprophyticus and Micrococcus luteus exogenously. Subcloning localized the enzymatic activities to the regions of high homology and demonstrated that the interposed sequence is responsible for the adhesive activities. Two allelic replacement mutants were constructed that lacked autolytic activity and adhesive properties. The N-terminal portion of the protein contains seven highly conserved, contiguous repeats with no similarity to published sequences. It lacks the motifs typical of Gram-positive surface proteins and shows a different overall organization. This autolysin/adhesin of S. saprophyticus (Aas) appears to represent a new class of staphylococcal adhesins.     

Surgical treatment of gastroesophageal reflux disease

Antireflux surgery is successful in 85-90% of eligible patients, with relief of symptoms, cure of oesophagitis and possibly prevention of progression of the dysplasia in a Barrett's oesophagus. The mortality in the latest publications is given as 0.05%. The morbidity, apart from recurrences, is not yet sufficiently known. Some 250 antireflux operations are performed annually in the Netherlands, fewer than 20% of the estimated requirement of 10 operations per 100,000 of the population per year, and also fewer than in Scandinavia. Nissen fundoplication (folding the fundus of the stomach around the entire circumference (360 degrees) of the oesophagus) is generally accepted as the standard primary operation. Nissen fundoplication during laparoscopy seems to be just as good. Results of randomized clinical trials will have to be awaited to prove this assumption. Belsey's operation (folding the fundus around 270 degrees of the circumference of the oesophagus via thoracotomy) is nowadays performed almost exclusively in recurrent reflux disease and in persistent dysphagia after a primary operation.     

Plasma L-arginine concentration, oxygenation index, and systemic blood pressure in premature infants

OBJECTIVE: To determine the relationships between plasma L-arginine concentrations and the severity of respiratory distress syndrome (RDS) or systemic blood pressure in premature infants. DESIGN: Prospective, observational study. SETTING: Neonatal intensive care, tertiary referral hospital. SUBJECTS: Fifty-three premature infants. INTERVENTIONS: We measured arginine and nutritional intake, plasma arginine concentration, total amino acid concentrations, and blood pressure on days 3, 7, 14, and 21 of life. In 33 infants who received assisted ventilation, oxygenation index could be calculated to reflect the severity of RDS. The relationships between plasma arginine and oxygenation index or blood pressure were analyzed using multiple linear regression. MEASUREMENTS AND MAIN RESULTS: On day 3, plasma arginine concentrations were decreased compared with normal published values. Arginine concentrations increased with the day of life of measurement (p < .001) and with arginine intake (p < .001). After adjusting for arginine intake and day of life, an inverse relationship was found between oxygenation index and plasma arginine concentrations: (p = .025). No similar relationship was found between oxygenation index and the concentration of total amino acids. A weak positive relationship was found between plasma arginine concentration and systemic blood pressure. CONCLUSIONS: Increments in the oxygenation index, reflective of an increased severity of RDS, are associated with a decrease in plasma arginine concentration. This finding may reflect arginine consumption by the nitric oxide synthase pathway in the lungs of premature infants with RDS, or may be explained by increased arginine catabolism. The lack of a similar relationship between total plasma amino acids and oxygenation index supports the first interpretation.     

Compression of the celiac trunk (author's transl)

Besides the vascular changes caused by arteriosclerosis the compression stenosis is the most frequent form of the isolated restriction of the arteria coeliaca. The compression of the arteria coeliaca, caused by the ligamentum arcuatum medianum or a fribromatous ganglion tissue, can cause complaints similar to the symptoms of angina abdominalis: pains in the epigastrium, postprandial pains, loss of weight, nausea/vomiting, diarrhea, 93% of the patients with severe vascular compression have an abdominal vascular murmur. Of 31 patients with angiographically proved compression stenosis, 11 patients suffering from occlusion or intense stenosis had to be operated because of heavy complaints. The angiographic and intraoperative findings allow the conclusion that there is a connection between the extent of the stenosis and the clinical appearance. The decompression of the arteria coeliaca, in other words the detachment of the compressing tissue leads to total complaintlessness in 83% of the patients. If the arteria coeliaca is hypoplastic a vessel widening or a bypass operation is necessary to establish normal blood circulation in the epigastric organs.