Aminopeptidase activity in human nasal mucosa

BACKGROUND: Aminopeptidases activate bradykinin and degrade many inflammatory peptides. OBJECTIVE: The objective of this study was to identify the types of aminopeptidase activities in human nasal mucosa. METHODS: Human nasal mucosa was homogenized (n = 12), and cytoplasmic (S2) and membrane-rich (P2) fractions were obtained. Several aminopeptidase (Ap) activities were defined by (1) substrate specificity with leucine-enkephalin (leu-Ap) and alanine-nitroanilide (ala-Ap), (2) inhibitor studies with puromycin and bestatin, (3) enzyme activity histochemistry (zymography), (4) immunohistochemistry, and (5) gel electrophoresis. Human volunteers had methacholine, histamine, and allergen nasal provocations to determine the mechanisms controlling nasal aminopeptidase secretion in vivo. RESULTS: P2 was the largest reservoir of puromycin-resistant aminopeptidase activity (630 pmol leu-enk/min/mg protein). S2 contained 32 pmol leu-enk/min/mg activity, with 80% representing puromycin-resistant activity and 20% puromycin-sensitive aminopeptidase (PS-Ap). Ala-Ap was detected in both P2 and S2 fractions and was localized by zymography to epithelial and gland cells. Anti-rat brain-soluble PS-Ap IgG detected immunoreactive material in epithelium, glands, and endothelium. In nasal provocation studies, leu-AP correlated with glandular exocytosis but not vascular leak. CONCLUSIONS: The predominant aminopeptidase in human nasal epithelial and submucosal gland cells was membrane-bound puromycin-resistant aminopeptidase. A novel soluble puromycin-resistant aminopeptidase and lower amounts of soluble PS-Ap were also detected.     

Sequences of MGH-1, YOU-1, and YOU-2 extended-spectrum beta-lactamase genes

Genes for MGH-1, YOU-1, and YOU-2 extended-spectrum beta-lactamases have been cloned and sequenced. The gene for MGH-1 has the sequence of blaTEM-10, YOU-2 has that of blaTEM-12, and YOU-1 has that of blaTEM-26. All have evolved from blaTEM-1b but have the strong dual promoter sequence of blaTEM-2.     

Prostaglandin production after experimental discectomy

STUDY DESIGN: This study ascertained the effects of discectomy on prostaglandin synthesis. OBJECTIVES: The purpose of these novel experiments was to measure the levels of two prostaglandins in lumbar epidural fluid obtained from an area subjected to discectomy. For comparison, lumbar epidural fluid from a site not disturbed by discectomy and fluid from a subcutaneous site were analyzed for the prostaglandins. SUMMARY OF BACKGROUND DATA: Previous studies have shown that nuclear material obtained from degenerative discs manifests an extraordinarily high level of phospholipase A2 activity. Others have hypothesized that the known inflammatory effects of phospholipase A2 are due to the release of arachidonic acid, which is converted to various eicosanoids, including several algesic prostaglandins (PGI2 and PGE2). No previous study has continuously measured prostaglandin levels in epidural fluid or assessed the effect of discectomy on prostaglandin production. METHODS: An ultrafiltrate of lumbar epidural fluid of dogs was obtained from indwelling catheters located adjacent to spinal areas that were and were not subjected to discectomy as well as from subcutaneous tissue. The fluid was collected daily for 14 days and analyzed for PGE2 and 6-keto PGF1(alpha) (the stable metabolite of PGI2) by radioimmunoassay. RESULTS: The concentration of 6-keto PGF1(alpha) and PGE2 in fluid collected during the first 24 hours was significantly higher in the area of discectomy than in the epidural region that was not subjected to discectomy and significantly higher than in fluid obtained from the subcutaneous site. The high level of these prostaglandins at the discectomy site fell rapidly, so that by the end of 48 hours the differences in values between spinal fluid from the discectomy and nondiscectomy regions were not statistically significant. The concentration of the prostaglandins in epidural fluid decreased with time and became minimal within the second week. CONCLUSION: The removal of normal discs is accompanied for 24 hours by a marked rise in the synthesis of two prostaglandins known to produce pain. Because the concentration of prostaglandins in epidural fluid decreased rapidly thereafter, the initial surge obtained appears to be associated more with chemical factors such as phospholipase A2 than with wound healing.     

The impact of routine obstetric ultrasonographic screening in a low-risk population

OBJECTIVES: Our goal was to develop a framework for evaluating the current controversy regarding routine obstetric ultrasonography in a population of low-risk pregnancies. STUDY DESIGN: A retrospective chart review was performed for all low-risk pregnancies from a single obstetric practice during 1990 to 1994, to determine the accuracy of screening ultrasonography for fetal anomalies. All patients received a routine ultrasonographic examination at 18 to 20 weeks' gestation. Neonatal records for all patients were evaluated for the presence of both major and minor anomalies. The data were analyzed with attention to the classification of anomalies (all anomalies vs major anomalies, detectable vs nondetectable). RESULTS: A total of 860 fetuses in 854 pregnancies were evaluated. Anomalies were present in 5.35% (46/860); these were major anomalies in 1.16% (10/860) and minor anomalies in 4.19% (36/860). The sensitivity, specificity, and positive and negative predictive values for the diagnosis of all anomalies were 8.7%, 99.9%, 80%, and 95.7%, respectively. However, if only major anomalies detectable by ultrasonography are included, these values become 75%, 100%, 100%, and 99.9%, respectively. There was one false-positive diagnosis not affecting outcome, a small ventriculoseptal cardiac defect. Postnatal ascertainment of anomalies was excellent, as determined by an incidence of ventriculoseptal defects of 1 in 120. CONCLUSION: Distinguishing between major and minor anomalies and between ultrasonographically detectable versus nondetectable anomalies is essential in the evaluation of the diagnostic accuracy of screening ultrasonography. Any comparisons of studies examining the effectiveness of prenatal screening for congenital anomalies with ultrasonography should use the same outcome: major anomalies identifiable by ultrasonography.     

Modification of experimental Porphyromonas gingivalis murine infection by immunization with a polysaccharide-protein conjugate

To better understand the role of the capsular polysaccharide in the virulence of Porphyromonas gingivalis, the effect of immunization with a polysaccharide-protein conjugate on experimental murine infection was evaluated. The conjugate was prepared using polysaccharide isolated from P. gingivalis strain ATCC 53977 and bovine serum albumin. One group of 22 mice was immunized by intraperitoneal injection with the conjugate and a control group of 25 mice was similarly immunized with bovine serum albumin. Serum antibody reactive to the polysaccharide, as determined by enzyme-linked immunosorbent assay, was elevated in the group of mice immunized with the polysaccharide-protein conjugate but not in the mice immunized with bovine serum albumin. Both groups of mice were challenged with P. gingivalis strain ATCC 53977 (10(10) cells) administered subcutaneously on the dorsal surface. Following challenge, the mice immunized with the polysaccharide-protein conjugate appeared healthier and demonstrated less weight loss than did the control group of mice. Ulcerative lesions at secondary locations were smaller in mice immunized with the polysaccharide-protein conjugate. Thus, immunization of mice with a conjugate containing P. gingivalis polysaccharide could reduce the severity of but not prevent an invasive infection with P. gingivalis.     

Effect of different dialysis membranes on platelet function. A tool for biocompatibility evaluation

Intradialytic coagulative and platelet activation, one of the main consequences of blood-membrane contact, was studied in a group of 5 RDT patients with a comparative evaluation of 3 different dialytic membranes: Cuprophan (CU), Polysulfone (PS) and Cellulose Triacetate (CT). Each patient underwent 5 consecutive dialysis sessions with the above mentioned membranes. Intradialytic platelet activation was studied through a morpho-functional evaluation between the mean platelet volume (MPV) and Serotonin (S), beta-Thromboglobulin (beta-TG) and Platelet Factor 4 (PF4) serum levels. These determinations were made before HD (time 0) and after 30', 120', and 240'. We also checked the intradialytic status of thrombogenesis and fibrinolysis determining aPTT, thrombin time, fibrinogen, antithrombin III (AT III), alpha-2 antiplasmin and plasminogen, at the same time intervals. All membranes tested (CU, PS, CT) caused appreciable intradialytic platelet activation, above all after 15' and at the end of dialysis sessions, more marked for CU than PS or CT. In particular MPV showed a decrease throughout the session (-5% at 30' and -9% at 240') while S, beta TG and PF4 peripheral blood levels showed a significant increase at the same intervals with CU membrane. Lastly coagulative and fibrinolytic parameters showed no significant differences among any of the membranes tested.     

The age-dependent incidence of injuries due to road traffic accidents in Odense, Denmark from 1980 to 1992

The study was based on data concerning persons treated at Odense University Hospital as a result of road traffic accidents in the period 1980-92. Incidence rates of road traffic accident injuries were calculated on the basis of the population in Odense municipality. The study group included persons older or even 65 years of age, while persons younger than 65 years of age were used as a reference group.     

Left atrial spontaneous contrast echoes--markers of thromboembolic risk in patients with atrial fibrillation

A consecutive series of 80 patients with atrial fibrillation were studied with both precordial and transoesophageal echocardiography. Left atrial spontaneous contrast echoes were observed in one patient with precordial echocardiography and in 26 patients (33%) with transoesophageal echocardiography. They were found most commonly in patients with rheumatic mitral valve disease (67%) but were observed in 28% of patients with lone atrial fibrillation. Their presence was unrelated to the age, gender and therapy of the patient. Although they were more common in patients with a large left atrium, they were sometimes observed in a normal sized atrial chamber. They were more common in chronic (40%) than in paroxysmal atrial fibrillation (5.6%). No patient had severe mitral regurgitation, but contrast echoes were observed in some patients with mild or moderate mitral regurgitation. Of the 26 patients with spontaneous contrast echoes, six (23%) had echoes consistent with left atrial thrombus compared to one of the 54 patients without these echoes (1.9%) (P = 0.006); 17 (65%) had suffered a previous thromboembolic event compared to 17 of the 54 without these echoes (32%) (P = 0.009). These data support the concept that spontaneous contrast echoes in the left atrium are associated with sluggish blood flow and a thrombogenic environment. Transoesophageal echocardiography may thus be useful in assessing which patients with atrial fibrillation might most benefit from anticoagulation. This hypothesis needs to be evaluated further in a prospective study.     

High-dose edatrexate with oral leucovorin rescue: a phase I and clinical pharmacological study in adults with advanced cancer

Our objective was to determine the maximum tolerated dose and toxicity of i.v. edatrexate with p.o. leucovorin. Thirty-one adults with advanced solid tumors received edatrexate as a 2-h infusion, once a week for 3 weeks, recycled every 28 days. p.o. leucovorin (10 mg/m2, every 6 h for 10 doses) began 24 h later. All had urinary alkalinization and p.o. hydration. Nine dosage levels ranging from 120 to 3750 mg/m2 were explored. Fatigue, epistaxis, nausea/emesis, mucositis, rash, myalgias, leukopenia, thrombocytopenia, and transient elevations of serum aspartate transferase were observed. Leukoencephalopathy with clinical manifestations occurred in two patients (one had prior cranial irradiation). Pharmacokinetic studies carried out at the 120- and 1080-mg/m2 dose levels revealed no significant difference in the elimination half-life at the two dose levels studied and no significant intrapatient variability between day 1 and day 8 edatrexate administration. Serum edatrexate levels measured using a dihydrofolate reductase inhibition assay correlated with those by high-performance liquid chromatography. Three major and two minor antitumor responses occurred. The maximum tolerated dose was 3750 mg/m2, with grade 3 or 4 leukopenia (one patient), stomatitis (one patient), and leukoencephalopathy (one patient). Because of the occurrence of leukoencephalopathy, further study of high-dose edatrexate with leucovorin rescue is not recommended.