Doppler echocardiographic evaluation of pulmonary artery pressure in pneumonia of infants and children

Previously, there was insufficient evidence to confirm that pneumonia in infants and children might lead to the development of pulmonary hypertension. Recently, it has been shown that acceleration time corrected for heart rate (ATc) and the ratios of right ventricular preejection period to right ventricular ejection time (RPEP/RVET) and of right ventricular preejection period to acceleration time (RPEP/AT) derived from Doppler echocardiography correlated well with pulmonary artery pressure (PAP). To approach PAP in patients with infantile pneumonia, we measured RPEP/RVET, RPEP/AT, and ATc in 105 infants and children with pneumonia and in 17 controls, using a commercially available 2-dimensional echocardiograph (Toshiba SSH-40A) with SDS-21B Doppler unit. An increase of varying degrees in both ratios and ATc was noted during acute illness and significant differences in ratios RPEP/RVET and RPEP/AT were found among patients with mild, moderate, and severe disease. This suggested that PAP increased to different extents in the acute stage of illness and that the degree of increase was related to the severity of disease.

[A survey on Campylobacter jejuni high infection in a nursery]

An epidemiologic survey on Campylobacter jejuni infection in a nursery was made in April 1987. It was found that there was a spread of C. jejuni high infection. Two cooks affected by enteritis of C. jejuni were considered to be a reservoir of the infection. Stool cultures were positive for C. jejuni in 43 out of 187 children, with a positive rate of 23%. Eight of the 43 had diarrhea and the others were asymptomatic carriers (24.3%). Controls were set up in another nursery with 238 healthy children and 201 non-diarrheal outpatients; C. jejuni was positive for 11.4% and 7.5%, respectively. The difference was quite significant (P less than 0.005). Results of biotyping on the strains isolated from the two cooks and the children in the nursery showed that all were of C. jejuni biotype 1, except two (4.7%) of the strains from the children, which were E. coli. The authors have suggested that transmission of C. jejuni in the nursery may be caused by contaminated food or person-to-person contact.

[Survey of Campylobacter jejuni/coli infection and risk factors in children]

From March to May 1987, 798 children under 7 years of the outpatients in Chengdu district were examined and their stool samples cultured for Campylobacter jejuni/coli. C. jejuni/coli was isolated from 31 (9.51%) of 326 children with diarrhea and 22 (4.66%) of 472 children with non-diarrhea. The difference was significant (P less than 0.05). This result indicated that C. jejuni/coli is an important pathogen of children diarrhea in Chengdu district. Meanwhile, by inquiry we investigated risk factors related with C. jejuni/coli infections. Case group was consisted of 53 children with C. jejuni/coli positive. For each case, 3 controls were chosen from 745 children with C. jejuni/coli negative and matched according to age (less than 6 month), sex, living place (city or countryside), way of feeding, and whether to have diarrhea or not. The results has shown that contact with animals a week before being ill and habit of intake of food with hands are risk factors of C. jejuni/coli infection of childhood in Chengdu, with an odd ratio of 2.97 and 2.71 respectively. This provides valuable information about the prevention of C. jejuni/coli infection.

Nonspecific immunocytochemical reactions with certain neurohormonal peptides and basic peptide sequences

Immunocytochemical staining experiments on filter paper or nitrocellulose models reveal that many, but not all, neurohormonal peptides, as well as poly-L-lysine, strongly bind a number of labeled reporter molecules, including colloidal gold- or peroxidase-labeled IgG, protein A, streptavidin, and albumin. Peptides displaying this type of (nonspecific) binding are basic; they include ACTH, VIP, opioid peptides, and poly-L-lysine. Pre-absorption of labeled probes with excess ACTH[1-24] or poly-L-lysine abolishes or greatly reduces binding not only to the homologous but also to the heterologous peptides tested. A number of cell types previously reported to display nonspecific immunoglobulin binding contain one or several of the basic neurohormonal peptides shown to display nonspecific absorption of labeled IgG, protein A, streptavidin, and albumin. This nonspecific absorption is reversed neither by high salt nor high pH conditions, nor by a number of detergents and blocking proteins. One dynorphin antiserum also displays nonspecific binding to the peptides as well as to pancreatic glucagon cells, and this nonspecific staining can be blocked by basic peptide pre-absorption (whether homologous or heterologous). These results suggest a need for caution when immunocytochemical studies of a number of basic polypeptides are interpreted, and also suggest the inclusion of novel control procedures in immunocytochemistry.

Simplified purification and testing of colloidal gold probes

A novel efficient method for purifying and testing colloidal gold probes has been developed. The method consists of concentrating colloidal gold particles conjugated to IgG or protein A in dialysis bags over silica gel and purifying them by gel chromatography on small columns of Sephacryl S-400. Fractions collected are tested by paper immunocytochemical models. Comparisons to gold probes purified by conventional ultracentrifugation documents that ultrastructural staining intensities and total yield of gold probes is the same, but that the chromatographically purified gold probes are less prone to aggregation or clumping. The method has been extensively used for preparing conjugates of 5, 10 or 15 nm gold particles with antirabbit immunoglobulins but has also been exploited for preparing streptavidin-gold conjugates, protein A-gold conjugates and antirabbit immunoglobulin-silver conjugates.

Simultaneous demonstration of multiple antigens by indirect immunofluorescence or immunogold staining. Novel light and electron microscopical double and triple staining method employing primary antibodies from the same species

Available techniques for light and electron microscopical double immunocytochemical staining are all associated with certain problems. We have developed a novel multiple staining procedure, which allows use of antibodies of differing specificities, raised in the same species (e.g. rabbit). Its essential features include 1) saturation of antigenic epitopes on the first layer primary antiserum by second (fluorophor- or gold-) labelled anti-IgG antibodies and 2) denaturation of free anti-IgG binding sites by formaldehyde vapour treatment. Various combinations of gastrin, somatostatin, glucagon, ACTH, growth hormone and enkephalin/endorphin antibodies have been tested at the light and electron microscopical level and have been found to give highly reproducible double- and triple-staining results. The technique has also been evaluated by use of cytochemical paper models. The method is simple and very useful for multiple staining of a wide variety of antigens.