Etiological diagnosis of influenza A virus by enzymatic radioimmunoassay.

An enzymatic radioimmunoassay for influenza A virus was developed by using polystyrene beads coated with rabbit immunoglobulin G to capture viral hemagglutinins (H1 and H3). Captured hemagglutinin was detected with goat immunoglobulin G followed by affinity-purified rabbit anti-goat immunoglobulin G labeled with alkaline phosphatase. [3H]AMP was added to quantify alkaline phosphatase activity, and free [3H]adenosine was measured with a scintillation counter. The assay detected as little as 0.1 ng of purified hemagglutinin. It was specific for hemagglutinin subtype and, depending on the source of the goat immunoglobulin G used, detected either H1 or H3. There was no reaction with neuraminidase or core antigens of influenza strain WSN-33. The clinical efficacy of the assay was evaluated with sequential nasal washes from 33 patients with naturally acquired H1N1 influenza. In the first 3 days of infection, the assay was consistently less sensitive than the viral culture, although detectable antigen persisted in secretions longer than did the infectious virus. Testing of multiple samples greatly increased the number of individuals in whom an etiological diagnosis could be made by immunoassay (81% of patients were positive for viral antigens at some point in their illness), and such testing was necessary to achieve the sensitivity of a single culture. Mean antigen levels were highest in nasal washes with the highest titers of infectious virus.     

Pneumococcal pneumonia: capsular polysaccharide antigenemia and antibody responses.

Capsular polysaccharide was detected in the serum in 19 of 46 patients with pneumococcal pneumonia. Antigenemia was strongly associated with bacteremia and with infection by low-numbered serotypes. During antibiotic therapy, the concentration of polysaccharide in the circulation declined progressively, but circulating antigen remained detectable in two thirds of cases for 2 weeks or longer. The development of measurable type-specific antibody was delayed in patients with antigenemia. It is not known whether this delay was due to diminished antibody production or to neutralization of antibody by circulating antigen. Despite effective antibiotic therapy many patients with antigenemia had a severe and protracted illness; this may have been related to diminished availability of antibody early in the infection.     

Can autism be diagnosed accurately in children under 3 years?

This study investigated the reliability and stability of an autism diagnosis in children under 3 years of age who received independent diagnostic evaluations from two clinicians during two consecutive yearly evaluations. Strong evidence for the reliability and stability of the diagnosis was obtained. Diagnostic agreement between clinicians was higher for the broader discrimination of autism spectrum vs. no autism spectrum than for the more specific discrimination of autism vs. PDD-NOS. The diagnosis of autism at age 2 was more stable than the diagnosis of PDD-NOS at the same age. Social deficits and delays in spoken language were the most prominent DSM-IV characteristics evidenced by very young children with autism.     

Species variation in the mechanism of killing of inhaled pneumococci

Detailed studies in murine models show inhaled staphylococci are killed mainly by alveolar macrophages. Recently, using histology and lung lavage to determine the site of killing of inhaled 59Fe-labeled pneumococci in rats, we found unexpectedly that most of the organisms were killed extracellularly. In the present studies we compared clearance of inhaled 59Fe-pneumococci in rats, guinea pigs, and rabbits to determine if extracellular killing of pneumococci is species-dependent. Absolute clearance rates were measured using Andersen plates. lung lavage and differential centrifugation were used to measure leukocyte-associated and free 59Fe-pneumococci and nonsedimentable 59Fe. Clearance was rapid in all species but was fastest in rabbits, which killed pneumococci almost as quickly as they were deposited (p less than 0.025 versus rats and guinea pigs). At 1-1/2 hours after pneumococcal deposition in rats, when clearance had reached 92%, alveolar macrophages contained only 31% of the total 59Fe while 56% was in the nonsedimentable, extracellular fraction. At 1-1/2 hours in guinea pigs, when clearance was 96% complete, macrophages contained 51% of the 59Fe and 34% was nonsedimentable (p less than 0.002 versus rats). In rabbits at 1-1/2 hours, macrophages had 94% of the 59Fe and only 4% was nonsedimentable (p less than 0.001 versus the other species). In no species were opsonic antibodies detected in sera or concentrated lavage. In vitro, rabbit and guinea pig alveolar macrophages killed pneumococci opsonized with both specific antibody and fresh serum, while rat macrophages had little activity (p less than 0.001). We conclude that the role of alveolar macrophages in killing inhaled pneumococci varies in different species.     

Cellular sources of thymidine nucleotides: studies for PET

The relative utilization of endogenously synthesized thymidine nucleotides and exogenously supplied thymidine analog was compared in a number of mammalian cell lines, tissues, and tumors. To measure the relative utilization, cells were incubated in tissue culture media containing the thymidine analog [3H]-5-bromo-2'-deoxyuridine (BUDR). After extraction of the DNA, the degree of substitution of the thymidine by BUDR was determined by density gradient centrifugation. All the cell lines and tissues tested utilized both exogenous BUDR and endogenous thymidine sources to a similar extent. The relative utilization of the exogenous pathway could be manipulated by varying the exogenous concentration of BUDR. Our results demonstrate that one can predict the relative utilization of these two pathways and can calculate the effective specific activity of the intracellular thymidine nucleotide pool. Such information is needed in interpreting 11C-labeled thymidine uptake as measured by positron emission tomography.     

PI-PLC releases a 25-40 kDa protein cluster from the hamster oolemma and affects the sperm penetration assay.

The effects of phosphatidylinositol-specific phospholipase C (PI-PLC) on human sperm-hamster oocyte interaction were investigated to determine whether PI-PLC cleavable glycosylphosphatidyinositol (GPI)-anchored proteins are involved in sperm-egg binding and fusion. Two-dimensional electrophoresis was then utilized to visualize proteins released from hamster oocytes following PI-PLC treatment. For the binding and fusion assay, either spermatozoa or eggs were treated with 1 IU/ml PI-PLC for 30 min and washed prior to gamete co-incubation. Treatment of human spermatozoa with PI-PLC significantly (P 相似文献   

Extracellular killing of inhaled pneumococci in rats

Early clearance of inhaled Staphylococcus aureus is believed to be caused by phagocytosis by alveolar macrophages. In murine models inhaled pneumococci are cleared even more rapidly than S. aureus. Conventional opsonins appear to play no role in this clearance, and recently it has been shown that murine alveolar lining material contains free fatty acids and other soluble factors that are directly bactericidal for pneumococci. To determine whether non-phagocytic factors are involved in pneumococcal clearance, we compared the site of killing of inhaled pneumococci and S. aureus in rats using histologic methods and bronchoalveolar lavage. Spontaneous lysis of pneumococci was prevented by use of autolysin-defective pneumococci or by substitution of ethanolamine for choline in the cell wall. Histologic studies showed that the percent of inhaled staphylococci associated with alveolar macrophages always exceeded the percent of staphylococci cleared, whereas there was little association of pneumococci with macrophages during clearance. Analysis of the intracellular or extracellular location of iron 59 in bronchoalveolar lavage fluid of rats that had inhaled aerosols of 59Fe-labeled bacteria suggested that staphylococci were killed predominantly in macrophages and pneumococci in the extracellular space. When 59Fe-labeled pneumococci or staphylococci were ingested and killed by macrophages in vitro, the 59Fe remained with the macrophages, suggesting that the extracellular location of 59Fe during pneumococcal killing in vivo was not caused by rapid turnover of 59Fe in macrophages. Studies of the site of killing of inhaled type 25 pneumococci labeled exclusively in the cell wall with carbon 14-ethanolamine confirmed the results obtained with 59Fe-labeled pneumococci. Thus, early killing of inhaled pneumococci, unlike staphylococci, appears to take place outside of macrophages.     

Assessment of AlbuSure and its usefulness in identifying IDDM subjects at increased risk for developing clinical diabetic nephropathy

This study, which included 154 participants in a 10-yr follow-up study of diabetes complications, was conducted to evaluate AlbuSure (a qualitative test designed to detect urinary albumin concentrations greater than 0.03 g/L) for its ability to discriminate between albumin concentrations above and below the manufacturer's concentration threshold and to identify individuals at increased risk for developing diabetic nephropathy (i.e., those with albumin excretion rate [AER] greater than 0.0288 g/24 h). The reproducibility of AlbuSure results was also evaluated. The results of these evaluations were examined by three different types of urine collections (24 h, overnight, and timed postclinic) and overall. AlbuSure's validity was examined by comparing its results to immunonephelometrically measured concentrations and AER. When compared to albumin concentration, AlbuSure had an overall sensitivity of 81.8%, specificity of 94.8%, and positive predictive value of 90.6%. AlbuSure's sensitivity was lower (71.4%) when compared with AER; however, this was higher than the sensitivity achieved by dipsticks against AER (50.7%). On testing urine samples stored for 3 days at 4 degrees C, AlbuSure results were 100% reproducible after 1 day and had an overall reproducibility of 92% after 3 days. When urine was retested after 3 and 15 mo of storage at -70 degrees C, AlbuSure was greater than or equal to 90% reproducible, with some of the differing results attributable to corresponding changes in albumin concentration. The overnight sample appeared to be the sample of choice for testing with AlbuSure in that it showed excellent reproducibility and the highest sensitivity (compared to both albumin concentration and AER).     

Additive inhibitory effects of progesterone and sodium nitroprusside on uterine contractility during pregnancy

Progesterone (P4) and nitric oxide (NO) suppress uterine contractility (CTX). This study compares the effects of P4 to sodium nitroprusside (SNP, an NO donor) and their combination on human CTX of term/preterm and labor/nonlabor tissues. Uterine tissues (n = 128) from women (n = 28) undergoing Cesarean were suspended in organ baths. Tissues (n ≥ 6/group) were treated with vehicle, P4, SNP, or combinations. A subset of tissues (n ≥ 2/group) from term/preterm ± labor and nonpregnant patients was analyzed with P4 alone. Analysis of variance (ANOVA) was used for statistical differences (P < .05). The combination of P4 with SNP significantly suppresses CTX (% inhibition of -127.1 ± 14.5) to the levels lower than with either P4 (-20.1 ± 8.6) or SNP alone (-72.0 ± 11.2). Suppression of P4 is similar in term, preterm, and nonpregnant tissues, with increased sensitivity in laboring tissues. This indicates that P4 or SNP alone may be used for preterm labor and their combination may be more successful.