Vi serology in the detection of typhoid carriers

A new haemagglutination assay for Vi antibodies was evaluated in searches for symptom-free carriers of Salmonella typhi associated with sporadic cases of typhoid fever. The assay differs from previous ones in that a purified (instead of crude) Vi antigen from Citrobacter was used to sensitise the red blood cells. In ten sporadic outbreaks of typhoid stool culture identified seven enteric carriers of S. typhi among the patients' families or other close contacts. All seven carriers had Vi antibodies in titres ranging from 1:40 to 1:2560. Moreover, among thirty-seven stool-culture-negative contacts of patients, only one had Vi antibodies, in a titre of 1:10. Thus, the new assay for Vi antibodies was as sensitive and as specific as faecal culture in detecting symptom-free typhoid carriers. It could become a convenient screening test.

Urethritis in women attending an STD clinic

Of an unselected group of 159 women attending a sexually transmitted diseases (STD) clinic 20% (32) had symptoms of urethritis. A positive correlation existed between the finding of more than 10 polymorphonuclear leucocytes (PMNL) per high-power field in the Gram-stained urethral smear and the presence of Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis. Conversely, these organisms were rarely isolated if no PMNL were present. Fewer cultures gave positive results for these organisms if micturition had occurred less than four hours before examination. C trachomatis was recovered from the urethra or endocervix in 29/150 (19 . 3%) and from the urethra alone in six women. In contrast, N gonorrhoea was never recovered from the urethra in the absence of endocervical infection. Of the 159 women 10% had bacteriuria due to non-sexually transmissible agents; 50% had asymptomatic bacteriuria. All, however, had other urethral pathogens isolated as well. Thus, sexually transmitted disease agents are highly prevalent in women attending an STD clinic who have signs and symptoms of urethritis. As in non-gonococcal urethritis in men, C trachomatis may be an important cause of urethritis in women.

Control of fat cell phosphohydrolase by lipolytic agents

The Mg2+-dependent phosphatidate phosphohydrolase activity increased in the microsomal and decreased in the soluble fraction of isolated rat fat cells incubated for short periods with the lipolytic hormones or agents, epinephrine, cyclic AMP, theophylline, and dibutyryl cyclic AMP. Adrenocorticotropin, on the other hand, increased not only the microsomal but also the soluble activity. The increases in microsomal activity ranged from 30 to 134% with epinephrine to almost 200% with dibutyryl cyclic AMP. The decreases in soluble activity were more modest. The effect of epinephrine was inhibited by the beta-adrenergic antagonist propranolol while the alpha-antagonist phentolamine enhanced it. These results strongly suggest that the fat cell phosphatidate phosphohydrolase is controlled through the beta-adrenergic receptor and the activity of adenylate cyclase. Lipolysis, as measured by fatty acid release, was stimulated in a similar pattern as the microsomal activity suggesting parallel activation of the hormone sensitive lipase and phosphatidate phosphohydrolase. It is speculated that the activation of this lipogenic enzyme by lipolytic stimuli may represent a mechanism whereby fatty acid release from adipose tissue may be modulated and intracellular fatty acid accumulation may be counteracted during accelerated lipolysis in adipose tissue.

The effect of naloxone on enkephalin catabolism

Naloxone strongly inhibited the breakdown of Met- and Leu-enkephalin when the substrate was incubated with brain homogenate, supernatant, or partially purified soluble aminopeptidase, but it had no effect on the mitochondrial fraction. Arylamidase was also inhibited by naloxone. The inhibitory effect of naloxone on the soluble aminopeptidase was in a linear relationship with concentration in the range of 8-500 microM. The KI for Met-enkephalin is 0.6 mM and for Leu-enkephalin is 2.0 mM. When the naloxone was administered intraperitoneally to the mice, its effects were somewhat different from its effects in vitro. It inhibited the brain catabolism of Met-enkephalin but not of Leu-enkephalin or Tyr-beta NA in vitro. In vivo, acute morphine in mice decreased the Met-enkephalin hydrolysis but increased the Leu-enkephalin hydrolysis. Chronic morphine (by morphine pellet implantation) increased the breakdown rate of enkephalin and of Tyr-beta NA. Naloxone (1 mg/kg) could not reverse the effects of morphine, although abstinence syndrome and stereotypical jumping were precipitated. Naloxone decreased the Leu-enkephalin level in the control mice but did not affect it in the addicted mice.

Degradation of melanotropin inhibiting factor by brain

Degradation of melanotropin inhibiting factor (MIF) was measured by fluorometry, using pareptide as an internal standard, following the separation of the dansyl derivatives of MIF and its metabolites by HPLc. MIF was not split by carboxypeptidases A and B, prolidase, or pyroglutamate aminopeptidase. It was hydrolyzed by leucine aminopeptidase, aminopeptidase M, and carboxypeptidase Y. Rat brain hydrolyzed 159 nmol of MIF per mg of protein per h; the activity was linear with enzyme concentration. Hydrolysis start from the N-terminal end, as shown by the appearance of proline as the first metabolite of the MIF degradation, followed by leucine, glycinamide, leucylglycine, and glycine. Activity in the rat brain regions was in the order striatum, medulla oblongata > cortex, hippocampus, midbrain > hypothalamus, cerebellum, and pituitary. The enzyme was mostly in the supernatant, with significant amounts in the myelin and synaptosomal fractions. MIF aminopeptidase could be separated from carboxypeptidase by centrifugation at 30,000 x g for 20 min and precipitation with 45--75% (NH4)2SO4. It showed pH optima in the alkaline range (8.25 and 8.75) and was inhibited by EDTA, EGTA, SQ 14,225, puromycin, bacitracin, and bestatin.

Murine infection model for contagious equine metritis: a new venereal disease of horses

An infection model in laboratory mice for studying the bacterium (proposed name Haemophilus equigenitalis) causing contagious equine metritis is described. Small porous chambers were implanted subcutaneously into mice and after 1 to 3 weeks were inoculated with H equigenitalis. Infections that persisted for > 30 days were established by direct transfer of infective chamber fluid or by injection of laboratory-grown cultures. Immunization of mice with formaldehyde-treated cells induced significant, strain-related immunity to infection and did not appear to require complement as a protection mediator. Substantial differences in staining characteristics and cell morphology were observed between bacteria grown in mouse chambers and those grown on a laboratory medium. These differences were more apparent in smears of the organism stained by a modified Gimenez method than in smears stained by the conventional Gram stain. This murine model may be a convenient and inexpensive method for studying the immunobiology of this newly discovered animal pathogen.

Evaluation of a new assay for Vi antibody in chronic carriers of Salmonella typhi

The assay for serum antibody to the Salmonella typhi capsular polysaccharide (Vi) antigen has recently been revised because of the availability of a purified, highly polymerized Vi antigen. We compared this revised Vi antibody assay to the traditional one for potential usefulness in the surveillance of chronic enteric carriers of S. typhi. The purified Vi antigen of Citrobacter freundii was incorporated into a passive hemagglutination assay for serum Vi antibody; the standard Vi antibody assay was also a hemagglutination assay that employed as the Vi antigen a crude extract of Citrobacter (Ballerup O group 29). As determined by the revised assay, Vi antibody was found in the sera of 22 (71%) of 31 current typhoid carriers, none of 6 resolved carriers, and none of 22 control subjects. According to the traditional assay, Vi antibody was present in 23 of those current carriers (74%), 1 of the resolved carriers (17%), and 4 of the control subjects (18%). The rate of false-positive Vi antibody tests among resolved carriers and control subjects was less with the revised assay (P < 0.05). Successful antimicrobial therapy resulted in a reversion to seronegativity within 1 year in 8 of 10 Vipositive carriers according to the revised assay, but in only 3 of 11 according to the standard assay (P < 0.05). During a 2-year period of observation, 15 (94%) of 16 current typhoid carriers had at least one positive purified Vi antibody test; among 12 of those patients with Vi titers of 1:40 or greater, 9 (75%) were continuously Vi positive. Thus, the revised Vi antibody assay is more specific and no less sensitive than the standard assay for the condition of current enteric carriage of S. typhi. This serological test could be of value in the surveillance of typhoid carriers by public health agencies.

The microbiology and therapy of acute pelvic inflammatory disease in hospitalized patients

We examined microbial isolates from the endocervical and peritoneal cavity of 30 women hospitalized with acute PID. Patients were randomly assigned to one of two antibiotic regimens: amoxicillin, 6 gm by mouth every 24 hours, or aqueous penicillin G, 30 million units and gentamicin, 180 to 240 mg intravenously every 24 hours. We measured response by quantifying physical examination findings. Neisseria gonorrhoeae was isolated from the cervix of 24 patients (80%) and from the peritoneal cavity of 10 (33%). Other peritoneal isolates included Enterobacteriaceae in five patients, Ureaplasma urealyticum in five, Mycoplasma hominis in six, and Chlamydia trachomatis in three. Bacteroides melaninogenicus, the most frequent anaerobe, was isolated in 11 cases. Bacteroides fragillis was not isolated from any specimen. The cure rates were the same for both regimens: three patients failed on each. Four women required total abdominal hysterectomy and unilateral or bilateral salpingo-oophorectomy.

Complement-enhanced immunity to infection with Neisseria gonorrhoeae in mice

Subcutaneous chambers were implanted in mice, injected with Neisseria gonorrhoeae, and supplemented with complement as a model for studying the immunogenicity and strain diversity of N. gonorrhoeae. Immunotypic resistance to N. gonorrhoeae in immunized mice was significantly (P less than 0.01) increased by injection of exogenous guinea pig complement into the host before challenge with gonococci. By using this model to test gonococcal isolates from various geographical areas, two highly immunogenic but immunotypically different gonococcal strains were identified. The piliated cells of these strains induced both complement-enhanced immunity and a degree of exogenous complement-independent immunity. The immunity in mice not treated with complement developed more slowly, was less effective, and waned earlier than that which was complement-dependent. Pretreatment with complement, although highly effective in preventing infection in immunized mice, was much less beneficial in terminating already established infections, even though bactericidal antibodies were present at the time of complement treatment. The mouse chamber model in which both complement-mediated and complement-independent mechanisms of protection can be evaluated may provide an additional tool for elucidating the immunology of gonococcal or other microbial infections.

Immunologic factors affecting the in-vivo and in-vitro survival of the Legionnaires' disease bacterium

Immunologic factors affecting viability of the Legionnaires' disease (LD) bacterium were studied in vitro and in vivo in mice and guinea pigs. In bactericidal tests, fresh human serum quickly killed LD cells. Heating fresh serum to 56 degrees C for 30 min destroyed bactericidal activity; absorbing it with bentonite had little effect. Fresh normal human serum was more effective than guinea pig serum. Adding LD cells to fresh normal human serum caused a greater than 50% depletion in functional complement activity, apparently by activating the classic C-142 pathway, because human serum deficient in C4 was not bactericidal. Antibodies to the Knoxville 1 LD strain in guinea pigs showed enhanced complement-mediated bactericidal activity. Without complement, immune guinea pig or human sera prolonged in-vitro LD cell survival. Antibodies to Knoxville 1 in mice depressed in-vitro bactericidal activity of human complement against Knoxville 1. In-vitro bactericidal tests support in-vivo studies in subcutaneous chambers. Complement-deficient mice immunized with Knoxville 1 were (P less than 0.01) less resistant to homologous challenge than nonimmunized mice. Immunized guinea pigs had a greater than 80-fold increase in resistance to subcutaneous-chamber infection.

Immunochemical, serologic, and immunologic properties of major antigens isolated from the Legionnaires' disease bacterium. Observations bearing on the feasibility of a vaccine

Two antigens were isolated from each of three strains of the Legionnaires' disease (LD) bacterium. One antigen was serotype-specific; the other cross-reacted with strains of LD bacteria of different serotypes. The serotypic antigens contained all the major branched-chain fatty acids characteristic of LD bacteria and were a lipid-protein-carbohydrate complex. Electrophoresis resolved the serotypic antigen of Knoxville 1 strain into four protein bands and one glycoprotein band with molecular weights ranging from 0.5 to 7.2 x 10(5). The specificity of the serotypic antigens was established by immunofluorescent staining, and double gel diffusion confirmed the absence of cross-reactions between the serotypic antigens of different types and the partial identity of the serotypic antigens from serologically related strains. The cross-reacting antigens formed precipitin bands with all the homologous and heterologous sera tested. Induction of immunity by vaccination with serotypic antigens was shown in three animal models using guinea pigs and mice. Passive-transfer of immunity (IgG) was also shown in mice and guinea pigs. These observations raise the possiblity of a vaccine for protection against infection of LD bacteria.

Nuclease enhancement of specific cell agglutination in a serodiagnostic test for Neisseria gonorrhoeae

Antiserum to a purified type R lipopolysaccharide antigen isolated from Neisseria gonorrhoeae was used in a slide agglutination test and compared with conventional carbohydrate utilization and fluorescent antibody tests to confirm the identity of laboratory cultures classified as typical or "atypical" N. gonorrhoeae. Cultures of Corynebacterium vaginalis, N. meningitidis, N. catarrhalis, N. sicca, and N. lactamicus were also tested in the slide agglutination procedure. The addition of both deoxyribonuclease and ribonuclease (1 mg/ml) to the cell suspension medium of phosphate-buffered saline improved the sensitivity and specificity of the agglutination reaction for N. gonorrhoeae. Problems relating to the agglutination test as an aid in identification of N. gonorrhoeae are discussed.

"Endotoxicity" of the Legionnaires' disease bacterium

The Legionnaires' disease (LD) bacterium is a gram-negative organism whose "endotoxicity" appears to differ in several respects from the classic endotoxicity generally associated with gram-negative bacteria. Discrepancies were noted between the high activity of LD bacteria in gelating limulus lysate in vitro and their low pyrogenicity in rabbits. Further in-vivo biologic tests indicated that LD bacteria were relatively weak in "endotoxicity". Analysis of LD bacterial cells and in their cellular fractions by gas-liquid chromatography indicated that LD bacteria did not contain hydroxy fatty acids commonly associated with lipid A of endotoxin. The branched-chain fatty acids that were characteristic of LD bacteria were associated with the cell envelope, and were readily extracted into organic solvents without prior saponification. The presence of 2-keto-3-deoxyoctonate in LD bacteria and cell extracts was detected by a microassay method but remains to be confirmed with gas-liquid chromatography and mass spectrometry. The active principle "endotoxicity" in LD bacteria may be a new type of bacterial lipopolysaccharide.

Immunological and serological diversity of Neisseria gonorrhoeae: identification of new immunotypes and highly protective strains

Gonococci, irrespective of serotype or immunotype, varied significantly in their capacity to induce immunity in animal models, and in vitro serological relatedness did not always insure in vivo cross-protection. By using a serum bactericidal assay followed by in vivo cross-protection studies, new immunotypic strains which were highly protective were identified from cultures isolated in different geographical areas and from patients with various clinical manifestations. Beta-lactamase production and gonococcal immunotype did not appear as related characteristics in that certain penicillin-sensitive strains were highly effective in immunizing animals against infection with beta-lactamase producers. The findings of this study emphasize the importance of using appropriate biological tests and strains for the investigation of gonococcal immunity and vaccine development. Immunization with a combination of a few major gonococcal immunotypic immunogens may provide substantial protection against the majority of penicillin-sensitive and beta-lactamase-producing gonococci. Investigation of isolated immunotypic immunogens is in progress.

Evidence for two distinct types of penicillinase-producing Neisseria gonorrhoeae

Since their recognition early in 1976, penicillinase (beta-lactamase)-producing Neisseria gonorrhoeae (P.P.N.G.) have been isolated in more than 15 countries. Most strains isolated in or epidemiologically linked with the Far East are relatively resistant to tetracycline in vitro, are phenotypically wild-type or proline-dependent auxotypes, and carry a plasmid with a molecular weight of 5800 000 (5-8 X 10(6)) daltons coding for beta-lactamase production. In contrast, P.P.N.G. epidemiologically linked with West Africa are more susceptible to tetracycline, require arginine for growth, and their gene coding for beta-lactamase synthesis is contained in a smaller 3-2 X 10(6) dalton plasmid. Moreover, 43% of the Far Eastern strains, but none of those from West Africa, have an additional 24-5 X 10(6) dalton conjugative plasmid which transfers the beta-lactamase R factor(s) to other gonococci. The presence of this conjugative plasmid may explain the relatively high prevalence of P.P.N.G. in certain areas of the Far East.

Virulence and immunogenicity of types 1 and 3 Neisseria gonorrhoeae in guinea pig subcutaneous chambers

The relative virulence and immunogenicity of type 1 (T1) and type 3 (T3) cells of Neisseria gonorrhoeae were determined by tests with two different kinds of subcutaneous chambers in guinea pigs. In tests with a tissue nonencapsulated (NE) chamber, T1 gonococci were found to be greater than 1000 times more virulent as well as about 1000 times more immunogenic than T3 cells of the same gonococcal strain. However, T1 and T3 cells were found to be equally virulent for a tissue encapsulated (TE) chamber in guinea pigs. Analysis of fluids from the two types of chambers in a complement-dependent bactericidal assay revealed that the NE chamber fluid contained a substantially higher level of complement activity than fluid from TE chambers. The decline in complement level of chamber fluids due to tissue encapsulation was also confirmed by quantitation with rocket gel electrophoresis. A greater resistance of T1 cells to the bactericidal effects of complement appeared to provide a mechanism by which the T1 cells were most virulent than T3 cells for subcutaneous chambers in guinea pigs. Consequently, the NE chamber implant would appear to provide a more relevant environment for studying the virulence, as well as immunological characteristics of gonococcal strains and experimental immunogens.

Comparative physical and immunological aspects of the chimpanzee and guinea-pig subcutaneous chamber models of Neisseria gonorrhoeae infection

Physical and immunological characteristics of the chimpanzee and guinea-pig subcutaneous chamber models for Neisseria gonorrhoeae infection were compared to evaluate their usefulness for gonococcal research. Urethral infection in chimpanzees anatomically resembled the human infection; however, individual variation in response, limited availability, and the presence of interfering micro-organisms in the urethra were found to limit the usefulness of the chimpanzee in immunological research. Although the guinea-pig subcutaneous chamber model may not be suitable for studying the attachment of gonococci to host cells or for the local production of IgA, it does have the immunological advantages of being more sensitive to infection, less variable in response, free of interfering micro-organisms, and is readily available to investigators. Except for differences in sensitivity and variability, results with the guinea-pig model paralleled results obtained in experiments with chimpanzees. Unlike chimpanzees, guinea-pigs are a comparatively inexpensive, rapidly replenishable animal, which after subcutaneous implantation with small porous chambers provide a convenient model for studying most immunological aspects of gonococcal infections.

Immunological and serological diversity of Neisseria gonorrhoeae: immunotyping of gonococci by cross-protein in guinea pig subcutaneous chambers

An in vivo typing system for studying the immunological relationship of gonococcal strains was established. Nine gonococcal strains of proven virulence for guinea pig subcutaneous chambers were selected, and these isolates were used to immunize groups of guinea pigs that were subsequently cross-challenged with graduated numbers of gonococci from these isolates. Resistance to infection was determined by culture of fluid from challenged chambers; results were expressed as the median dose, in colony-forming units, of gonococci required to produce infection in each group of immunized guinea pigs. This information was then used to develop immunotypes of gonococci based on the cross-protection results obtained. Four cross-protecting immunotypes were established from the preliminary nine strains tested.

Immunological and serological diversity of Neisseria gonorrhoeae: gonococcal serotypes and their relationship with immunotypes

Strains of gonococcus were shown to be immunologically heterologous. Serum bactericidal activity generally correlated with induced immunity to gonococcal challenge as detected by the guinea pig subcutaneous chamber model. Sera devoid of bactericidal activity reflected the lack of cross-protection in subcutaneous chambers. Factors affecting the bactericidal assay described in this report include (i) source of complement, (ii) concentration of test antigen and complement activity, and (iii) presence of calcium and magnesium ions and bovine serum albumin in diluent. Poor correlation was observed between agglutinating activity of the immune sera and protection.

The value of endoscopic study of the bile ducts and the pancreas in the elderly

Endoscopic retrograde cholangiopancreatography was performed in 46 patients age 60 or older with various suspected pancreaticobiliary or duodenal diseases. Thirty-one patients (67.4%) had diagnostically satisfactory opacification of a duct system. Pathologic conditions obstruction injection of the contrast medium prevented opacification in eight patients (17.4%). Seven cannulations (15.2%) were technical failures. There was one complication, a Gram-negative septicemia that was successfully treated. The procedure is of value in the geriatric patient because it may provide preoperative evidence of pancreatic or biliary disease that cannot be diagnosed by any other technique. In jaundiced patients, identification of the site of obstruction facilites the surgical approach and thus reduces operating time. If the common bile duct is shown to be patent, the patient is spared exploratory surgery or a prolonged hospital stay for observation. Although a normal pancreatic duct does not exclude cancer of the pancreas, it should influence the physician to search for other explanations for abdomianl pain or weight loss befror proceeding with abdominal surgery.

Vi antigen from Salmonella typhosa and immunity against typhoid fever. 11. Safety and antigenicity in humans

Safety and antigenicity of a purified preparation of Salmonella typhosa Vi antigen was evaluated in human volunteers. Dosages of Vi antigen at 25, 50, and 100 mug were less toxic than U.S. standard typhoid vaccine (lot 6A) containing 5 X 10(8) bacteria per dosage. Vi antigen in comparison with the standard typhoid vaccine induced higher hemagglutinating antibody but lower bactericidal antibody responses.