Growth conditions mediate differential transcription of fim genes involved in phase variation of type 1 pili

Type 1 pili in Escherichia coli undergo phase variation in which individual cells in a population reversibly switch between piliated (Pil+) and nonpiliated (Pil-) states. The switching process is mediated by an invertible DNA fragment which contains the promoter for fimA, the gene encoding the major structural subunit of type 1 pili. Although type 1 pili randomly phase vary in broth cultures, many clinical isolates of E. coli do not express type 1 pili when cultured on agar media. We investigated the role of the invertible element and the upstream genes, fimB and fimE, in the agar-mediated suppression of pili in an agar-negative clinical isolate, strain 149. Southern hybridization and polymerase chain reaction analyses of the fimA promoter region in broth-grown 149 cells indicated that the invertible element was present in orientations corresponding to both Pil+ and Pil- phenotypes. In contrast, only one orientation of the invertible element, corresponding to the Pil- phenotype, was observed in strain 149 cells cultured on agar. A second clinical isolate, strain 2-7, which expresses type 1 pili on agar was also examined; the invertible element was found in both the Pil+ and Pil- orientations during growth of this strain on agar as well as in broth. The introduction of the fim gene cluster from strain J96 on a multicopy plasmid into agar-negative strain 149 resulted in the production of both J96 and 149 pili during growth on agar. Experiments with subclones of the J96 genes indicated that the presence of an intact fimB gene allowed strain 149 pili to be produced on agar. Differences in pilus production between agar and broth cultures appear to be the result of differential transcription of fimB and fimE under the two growth conditions. In contrast, the pattern of expression of these genes in agar phase-variable strain 2-7 did not differ between broth- and agar-grown cells.

Efficacy of some anthelmintics on an ivermectin-resistant strain of Haemonchus contortus in sheep

Following evidence of reduced efficacy of ivermectin in a field population of Haemonchus contortus in Brazil, this strain of the parasite was submitted to a controlled anthelmintic test. Eighty worm-free lambs were randomly split into two groups of 40. Each lamb in the first group was infected with 5000 third stage larvae (L3) of the ivermectin-resistant strain; the remaining 40 lambs were each infected with 5000 L3 of a H. contortus strain of known susceptibility to the major groups of anthelmintic compounds used in sheep. On Day 28 post-infection, each group was subdivided according to egg counts and at random into four sub-groups of ten lambs, each of which was treated with albendazole (ABZ) at 3.8 mg kg-1, levamisole (LEV) at 7.5 mg kg-1 or ivermectin (IVM) at 0.2 mg kg-1, or was left as untreated control. At slaughter, 7 days later, all the anthelmintics reduced worm burdens in animals infected with the susceptible strain (ABZ 98.9%, LEV and IVM 100%). By contrast, in the lambs infected with the ivermectin-resistant strain, LEV was 99.8% effective, but ABZ reduced worm counts by only 14.7% and IVM by only 10.4%. Interestingly at necropsy on Day 7 post-treatment, the egg counts in the resistant strain treated with ABZ had been reduced by 92.5%, although worm counts were reduced by only 14.7%.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathophysiological studies on Dicrocoelium dendriticum infection in sheep

Red cell kinetics and plasma protein metabolism were investigated in two experiments using 20 adult sheep naturally infected with Dicrocoelium dendriticum, but free of other liver and gastrointestinal helminths. In the first experiment, where groups of animals with low to high Dicrocoelium burdens were injected with 51Cr-labelled red cells and 125I-labelled albumin, the results indicated that there were no significant differences in the turnover rate of labelled red cells or albumin between any of the groups. In the second experiment, two groups of sheep with low and high worm burdens were studied using the same radioisotope tracers; in addition, 59Fe-citrate was used to assess red cell iron incorporation rates in the two groups. Although the red cell half-lives of the infected sheep were just significantly longer, both were within normal limits and the difference was attributed to random variation within the two small groups of sheep. No significant differences were found in the other parameters. It was concluded that burdens of up to 4000 D. dendriticum do not cause significant blood or plasma protein loss in sheep.

Pathophysiology of Haemonchus placei infection in calves

This study was conducted to investigate the pathophysiology of Haemonchus placei infection in Friesian calves. Seven calves were divided into two groups, three uninfected calves (control group) and four infected animals. The latter group were infected orally with 500 H. placei larvae kg-1 body weight. Five weeks after infection they were all housed in metabolic crates and injected with 125I-bovine albumin. 51Cr-red cells and 59Fe-transferrin, to study albumin metabolism, erythrokinetics and ferrokinetics. The results showed that there was a significant reduction in the mean haematocrit values and reduced weight gains in the infected calves compared with the controls. There was also a change in the distribution of albumin from the extravascular to the intravascular pool and a significant increase in the plasma and blood volumes of infected calves although the blood and albumin loss via the gastrointestinal tract recorded in this study was similar in both groups.

The use of CA15.3 as a serum tumour marker in breast carcinoma

There is, as yet, no tumour marker which is sufficiently specific and sensitive for use in the routine assessment of breast cancer patients. CA15.3 is a recently described tumour marker determined by two monoclonal antibodies. We have estimated CA15.3 by immunoradiometric assay in 187 patients attending a breast clinic. Eighty-one patients with benign disease were used as controls and 32 U/ml was taken as the upper limit of the normal range (means + 3SD = 31.7). Of 58 women with Stage I and II disease, only four had abnormal concentrations of CA15.3 and all are disease-free at a mean follow-up of 31 months. Seven women with normal CA15.3 concentrations developed recurrent disease at a mean of 18.7 months (range 10-25 months). Seven-day postoperative values were significantly lower than pre-operative values. There was no association between the CA15.3 value and the axillary nodal status. The patients with disseminated disease had a wide range of CA15.3 concentrations and there was no association between the CA15.3 concentration and the apparent tumour load.

The value of assessing cell proliferation in breast cancer

Using three methods to measure cell proliferation, namely DNA cell cycle; anti-proliferating cell monoclonal antibody (MAb) (Ki67, P145) analysis by flow cytometry; and the histological silver (argyrophilic) staining technique to visualize nuclear-organizing regions (AgNOR), twenty-two paired samples of primary breast tumour and axillary lymph node were analysed. The results showed variable levels of correlation between the methods used for the tumour group (r = 0.915, P less than 0.001 for Ki677 versus P145; r = 0.42, P less than 0.005 for percentage S/G2/M-phase versus P145; r = 0.16, P less than 0.5 for percentage S/G2/M-phase versus AgNOR; r = 0.400, P less than 0.1 for Ki67 versus AgNOR). The lymph-node group showed slightly poorer correlations, yet involved nodes showed a consistently higher level of proliferation than non-involved nodes by all methods used. Overall, MAb binding of Ki67 or P145 was seen to be a good indicator of cycling cells, detecting G1-phase cells in addition to S/G2/M-phase cells identified by the other methods used. However, no advantage was found over the usual DNA flow cytometric analysis of cells, which had clear prognostic value. AgNOR scores were found to be able to discriminate between diploid and aneuploid; and dividing and non-dividing cells, but areas of score overlap limited the application of this technique to that of a positive discriminator only.

Mannose-sensitive haemagglutination in the absence of piliation in Escherichia coli

The relationship between type 1 pilus structure and the mannose-sensitive adhesin was investigated by analysing the properties of an 11.2 kb fragment of DNA derived from the chromosomal pil region of a type 1 piliated uropathogenic strain of Escherichia coli. The recombinant plasmids pHA9 and pSJH9, containing the cloned fragment, conferred a mannose-sensitive haemagglutination (MSHA)-positive but non-piliated phenotype on recipient cells of ORN104. Most of the DNA sequences homologous to the pilA and hyp genes were not present in the 11.2 kb insert, and the genetic information necessary for MSHA in the absence of piliation spanned a 6.5 kb region of the cloned fragment. The polypeptides expressed by pSJH9 were examined in minicells and Tn1000 insertions in three genes encoding proteins of molecular weights 90 kD, 29 kD and 17 kD abolished the MSHA phenotype.

Bacteria as solid phase in a concentration fluorescence immunoassay analysis of antibodies to surface antigens

A modified solid-phase fluorescence immunoassay was developed using bacterial cells as the solid phase to screen antibodies produced against surface antigens from a clinical isolate of Escherichia coli, strain 1-149. The bacterial solid phase was used to analyze both polyclonal and monoclonal antibodies. The bacterial concentration fluorescence immunoassay (BCFIA) showed up to 50-fold greater sensitivity in bacterial cell detection as compared to ELISA (enzyme-linked immunosorbent assay). Moreover, BCFIA was considerably faster than ELISA with uniform reproducibility. This paper demonstrates the utility of using bacteria and their surface antigens as solid-phase matrices for antibody characterization in a FIA.

In vivo expression and variation of Escherichia coli type 1 and P pili in the urine of adults with acute urinary tract infections

In vivo expression of pili by Escherichia coli in the urine of 41 adults with lower urinary tract infections was analyzed by immunostaining with polyclonal antiserum to type 1 and P pili. Type 1 pili were detected in 31 of 41 urine specimens, while P pili were detected in 6 of 18 specimens. The piliation status of bacterial populations in urine was heterogeneous, varying from predominantly piliated to a mixture of piliated and nonpiliated cells. Bacteria frequently adhered to exfoliated uroepithelial cells and leukocytes in urine. Expression of pili in vivo did not always correlate with the hemagglutination phenotype after growth in vitro. Strains isolated from different sites in the urogenital tract of two individuals showed phenotypic variation in the state of piliation. The results demonstrate that E. coli type 1 and P pili are expressed and are subject to variation in vivo during acute urinary tract infections in adults.

World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) guidelines for evaluating the efficacy of equine anthelmintics

These guidelines have been designed to assist in the planning, operation and interpretation of studies which would serve to assess the efficacy of drugs against internal parasites of horses. Although the term anthelmintic is used in the title and text, these guidelines include studies on drug efficacy against larvae of horse bot flies, Gasterophilus spp, which are non-helminth parasites commonly occurring in the stomach of horses. The advantages, disadvantages and application of critical and controlled tests are presented. Information is also provided on selection of animals, housing, feed, dose titration, confirmatory and clinical trials, record keeping and necropsy procedures. These guidelines should assist both investigators and registration authorities in the evaluation of compounds using comparable and standard procedures with the minimum number of animals.

Noninvasive diagnosis and treatment of atrial flutter utilizing previously implanted dual chamber pacemaker

Patients with previously implanted dual chamber pacemakers (PM) may develop atrial flutter (AFL). The Siemens-Pacesetter AFP and Genesis PM have the capability of noninvasively synchronizing to a standard external electrophysiology (EP) stimulator. Any arrhythmia termination or induction protocol may be used with a refractory period limitation of approximately 127 msec (472 ppm). The PM stimulation sequence is directly controlled by the APS Model 370EP Programmer which acts as an interface between the PM and EP stimulator. All testing is conducted with the PM functioning in a single chamber mode. The external EP stimulation is detected by the programmer and a 37 KHz coded radio frequency transmission is used to control the PM stimulation in a 1:1 fashion. Real-time intracardiac electrograms (IEG) can be recorded from either the atrial (A) or ventricular lead. The IEG can be used for: (1) hard-copy for diagnosis and cycle length determination; (2) monitoring during and after the procedure; and (3) a synchronization signal to the EP stimulator. Two patients presented with three episodes of AFL with A rates ranging from 220-290 bpm. An A-IEG was obtained in each case to document the exact rhythm and rate. Rapid A pacing from 300-340 ppm was accomplished using a standard external rapid A pacemaker in concert with the 370EP programmer and PM. In two episodes, the AFL accelerated to transient A fibrillation followed by spontaneous conversion to sinus rhythm (SR). In the other episode, the AFL converted directly to SR.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevention and termination of pacemaker-mediated tachycardia in a new DDD pacing system (Siemens-Pacesetter model 2010T)

The clinical incidence of Pacemaker-Mediated Tachycardia (PMT) has been substantially reduced with the availability of wide range postventricular atrial refractory period (PVARP) programmability in most current technology DDD pacemakers. However, patients may still be at clinical risk for PMT if the PVARP must be reduced to allow higher atrial tracking capability or VA conduction (VAC) is not periodically assessed to ensure adequate PVARP selection. A new DDD pacer (Siemens-Pacesetter Model 2010T) incorporates programmable responses to a sensed PVC to prevent PMT induction due to VAC following a PVC. In each of these responses, the PVARP is automatically extended to prevent detection of the retrograde P wave, thus preventing the PMT. Additionally, should a PMT occur for reasons other than a PVC, the selected PVARP extension algorithm is periodically invoked to terminate the PMT. This study was conducted to evaluate the operation and clinical benefit of these PVC response functions and PMT termination capabilities. The exact timing operation of the pacer during these responses is also reviewed.

Role of Escherichia coli adhesins in urethral colonization of catheterized patients

Escherichia coli is a major cause of catheter-associated urinary tract infection and frequently colonizes the urethra prior to invading the urinary tract. Bacterial pili, filamentous protein cell surface-associated appendages, have been shown to mediate colonization of epithelial cells. Pili associated adhesins can be detected in vitro by their ability to mediate bacterial hemagglutination of erythrocytes. We have assessed the role of bacterial adhesins in supporting urethral colonization by determining the hemagglutination reactions of 56 E. coli isolates from the urethra of patients with indwelling urethral catheters. The adhesin detected most frequently was the type 1 mannose-sensitive hemagglutinin (43%), and 43% of isolates failed to hemagglutinate guinea pig or human erythrocytes. E. coli hemagglutinins were no more common on urethral isolates from patients that were persistently colonized (E. coli present 70% of the time catheterized), than from those that were transiently colonized (E. coli present 30% of the time catheterized). Analysis of the HA reactions and DNA plasmid profiles of multiple isolates from persistently colonized patients suggested that the E. coli strain colonizing the urethra changed over time. The data suggest that bacterial colonization of the urethra is mediated in part by adhesins and changes over time.

Tuberculosis: a surgical viewpoint

Over the past 15 years, 32 cases of tuberculosis have been seen and diagnosed in the surgical and gynaecological departments of the Northern General Hospital, Sheffield. The average age of patients was 42.8 years. Of the sites affected, 17 had head, neck or axillary swellings, 6 affected the female genital tract, 3 had intra-abdominal tuberculosis, 2 presented with soft tissue swellings on the trunk or limbs, 2 affected the male genitourinary system, whilst the remaining cases presented with an ischiorectal and psoas abscess. The time delay between initial consultation and diagnosis being established was between 1 and 8 months. In only 7 (21.8%) cases was a correct preoperative diagnosis made, with only 8 patients being clinically unwell at presentation. Twenty-three received antituberculous chemotherapy and there was one death. Tuberculosis will not be diagnosed or correctly treated unless it is considered in the differential diagnosis and appropriate specimens sent for bacteriology and histology. We conclude that tuberculosis is still prevalent in the surgical departments and both general surgeons and gynaecologists should consider the diagnosis more frequently than is currently the case.

Forms of bovine pepsinogen in plasma from cattle with three different 'syndromes' of Ostertagia ostertagi infection

Calves infected orally with third stage larvae of Ostertagia ostertagi or infected with adult O ostertagi by direct transplantation into the abomasum had raised plasma pepsinogen activity, as did four-year-old dairy cattle challenged with O ostertagi third stage larvae on five occasions. Using fast protein liquid chromatography two forms of pepsinogen; pepsinogen 1 (PG1) and pepsinogen 2 (PG2) were identified in each of the parasitic infection regimes.

Review of a hospital experience of breast abscesses

A retrospective review of breast abscesses during a 10-year period was performed. Only 8.5 per cent (6/72) of patients were in the puerperium. Peripherally sited abscesses were predominantly staphylococcal in origin, incision and drainage was effective treatment in all. By contrast, a subareolar abscess yielded a higher proportion of anaerobic bacteria and 46 per cent (13/28) of these patients had duct ectasia. We conclude that in present day practice a breast abscess is more likely to be related to duct ectasia than to the puerperium, and that patients with anaerobic infection or subareolar abscesses should be assumed to have duct ectasia and may require excision of the major duct system (Hadfield's procedure).

Relationship of type 1 pilus expression in Escherichia coli to ascending urinary tract infections in mice

The role of type 1 pili and P adhesins during the in vivo growth of Escherichia coli inoculated into the urethras of BALB/c mice was studied. Strains which produced type 1 pili when grown in broth but lost this trait when grown on agar (regulated variants) were tested. Broth-grown organisms colonized the bladder of every animal tested, with counts of 10(3) to 10(4) viable organisms recovered from bladder homogenates. Agar-grown organisms gave lower rates of infection and the number of viable organisms recovered from bladders was significantly reduced. The degree of inoculum piliation influenced bladder colonization in a direct way: as piliation increased, the number of bacteria recovered from bladders also increased. After intraurethral inoculation, all of the bladders and 44% of the kidneys were colonized on day 1, and by day 5, 94% of the bladders and 16% of the kidneys were positive. Hemagglutination titers remained high for the bladder isolates, but the organisms colonizing the kidneys became significantly less piliated with time. Bacteriuria was unrelated to bladder or renal colonization. Strains that demonstrated random phase variation of type 1 pili during growth on agar produced similar colonizations of the urinary tract with broth- and agar-grown inocula. Strains that produced only P adhesins were less effective in colonizing the urinary tract than were type 1 piliated organisms. Other strains which did not produce pili only minimally colonized the bladder. The results suggest that type 1 pili play an essential role in ascending infections of the urinary tract.

An evaluation of the efficacy of netobimin against Dicrocoelium dendriticum in sheep

A trial was carried out to assess the efficacy of a nitrophenylguanidine compound, netobimin against Dicrocoelium dendriticum in naturally infected sheep. At a dose rate of 20 mg/kg bodyweight administered orally the drug was highly effective, producing a mean reduction of 98.9 per cent in the fluke burdens of treated animals compared with untreated controls. No side effects were observed in the treated sheep.

Further studies on the response to transplanted adult Ostertagia ostertagi in calves

Calves infected by surgical transplantation of adult Ostertagia ostertagi had raised levels of plasma pepsinogen and those in which the largest number of worms established also had elevated plasma gastrin concentrations. Despite the elevated plasma pepsinogen values, the abomasal pH of the animals did not change significantly, and there was no significant difference in the percentage establishment of adult parasites in calves previously infected with O ostertagi third stage larvae and those which had been maintained parasite-naive before transplant.

Regulation of production of type 1 pili among urinary tract isolates of Escherichia coli

The piliation and hemagglutination properties of 54 consecutive Escherichia coli isolates from women with recurrent urinary tract infections were studied. Mannose-sensitive hemagglutination (MSHA) of guinea pig erythrocytes, characteristic of type 1-piliated bacteria, was produced by 75% of the isolates, 32% produced mannose-insensitive hemagglutination, and 14% produced no hemagglutination reaction. The production of type 1 pili was examined in those strains that produced MSHA only. Studies with antiserum prepared against purified pili suggested that at least three subtypes of type 1 hemagglutinins were represented among the isolates. All of the type 1-piliated isolates produced MSHA after serial subculture in static broth. After growth on agar, selected type 1-piliated isolates were subdivided into two groups. Many strains apparently suppressed piliation during growth on agar (regulated variants); all colonies became MSHA negative and were composed of nonpiliated cells as shown by electron microscopy. The loss of the MSHA phenotype often occurred after a single overnight passage on agar, and any remaining hemagglutinin was gradually lost with one to three additional passages. Seven strains, however, retained a significant hemagglutination titer after multiple subcultures on agar, and they produced colonies consisting of a mixed population of piliated and nonpiliated cells. These strains were apparently able to oscillate between states of pilus expression and nonexpression during growth on agar (random phase variants). When nonpiliated cells isolated from the mixed, random variant population were plated on agar, they gave rise to hemagglutination-positive colonies that consisted of both piliated and nonpiliated cells. The distinction between random variants and regulated variants was also observed in shaking broth cultures inoculated with nonpiliated cells. The random variants produced MSHA-positive cultures composed of piliated and nonpiliated cells, whereas the regulated strains remained nonpiliated. The results indicate that type 1 pili are a predominant adhesin of uropathogenic E. coli and that during growth on agar only about one-fourth of the type 1-piliated isolates regulate pilus expression by random phase variation.

Characteristics and clinical effects of myopotential signals in a unipolar DDD pacemaker population

Myopotential signals were recorded from atrial and ventricular leads during isometric exercise in 25 patients who had chronically implanted dual chamber pacemakers using the electrogram telemetry capability of the pacemakers. Average electrogram amplitude on the atrial channel was 0.92 mV (range 0.3 to 1.9) and on the ventricular channel was 0.98 mV (range 0.3 to 2.2); the difference was not significant. There was a strong correlation (R = 0.82) between the amplitude of myopotentials on the atrial and ventricular leads for individual patients. Myopotential sensing caused ventricular output inhibition in two patients (8%) and ventricular tracking in sixteen patients (64%). Pacemaker reprogramming abolished ventricular myopotential inhibition in all patients and stopped ventricular myopotential tracking in seven patients. We conclude that myopotentials can be analyzed and their effects ameliorated by a multiprogrammable pacemaker with electrogram telemetry capability.

Response to transplanted adult Ostertagia ostertagi in calves

Plasma pepsinogen levels became elevated in groups of recipient calves immediately after transplant with adult Ostertagia ostertagi. These rises occurred in both previously parasite-naive calves and in calves which had experienced prior infection terminated with an anthelmintic either seven or 21 days before transplant. From the results it appears that adult O ostertagi play a significant role in the elevated plasma pepsinogen levels associated with bovine ostertagiasis.

Studies on the abomasal pathology of immunized and non-immunized sheep infected with Haemonchus contortus

Five adult ewes and five lambs were repeatedly immunized with weekly doses of 10,000 irradiated Haemonchus contortus L3 before challenge with 100,000 and 10,000 normal larvae respectively. Two groups of non-immunized ewes and lambs were similarly challenged and one animal from each of the four groups killed on days 3, 5, 7, 10 and 24 post-challenge. The cellular changes in the abomasal mucosa were less marked in the non-immunized groups than in the immunized animals and appeared later in the lambs than in the ewes. Thus, in the immunized ewes increases in the numbers of mast cells and eosinophils were evident within five days of challenge whereas similar changes appeared later in the immunized lambs. Also marked lymphoid aggregates at the base of the mucosa and in the submucosa were detected only in the immunized ewes. However, both immunized and non-immunized ewes showed rises in the numbers of IgA plasma cells after challenge which were not evident in either group of lambs.

Role of type 1 pili and effects of phase variation on lower urinary tract infections produced by Escherichia coli

Phase variation of type 1 pili (fimbriae) was studied during the in vivo growth of Escherichia coli in two animal models. In the first, a heavily piliated urinary tract isolate (strain 149) was placed in 1-cm polypropylene chambers sealed with 0.22-micron-pore-size filters. The chambers were surgically implanted intraperitoneally in mice and recovered at various times. Piliation, as determined by electron microscopy and by measuring the minimum number of bacteria needed to produce mannose-sensitive hemagglutination, gradually decreased, and by day 5, most of the organisms were nonpiliated. In the second model, piliated and nonpiliated E. coli phase variants were inoculated into the bladders of BALB/c mice via urinary catheters, and their fate in the lower urinary tract was studied. Viable counts of bladder homogenates revealed that piliated phase variants were significantly more effective in colonizing the bladder urothelium than were their nonpiliated counterparts. Specific antibody to type 1 pili prevented colonization by the piliated organisms. After inoculation of piliated variants, the bladder-associated bacteria gave rise to approximately 80% mannose-sensitive hemagglutination-positive colonies, and immunocytochemistry of bladder lavages revealed large numbers of type 1 piliated bacteria adhering to the bladder transitional cells. Electron microscopy confirmed the presence of piliated bacteria in association with the bladder urothelium. The urine of these mice, whose bladders were colonized with piliated bacteria, frequently showed no growth, and when bacteria were present, strain 149 yielded less than 30% hemagglutination-positive colonies. The results suggest that for some E. coli strains, phase variation may be a factor in determining the fate of the E. coli in the urinary tract and that the urine may not necessarily reflect the bacteriologic state of the bladder mucosa.

Post operative stimulation of cell mediated immunity

The consequences of altered immuno-competence resulting from anaesthesia and surgery are potentially hazardous to the patient with malignant disease. Malnutrition also produces reduction in cell mediated immunity, a condition which is commonly incurred in patients with neoplastic disorders. Numerous agents have been claimed to stimulate the immune responses but few have proved to be of practical value. This paper reports the use variously of protease inhibitors, using Aprotinin, and post operative nutritional therapy, following major surgical resection for carcinoma - specifically as regards their influence on parameters believed to relate to cell mediated immunity. No clinical, metabolic or immunologic benefit was identified from either method of post operative stimulation of cell mediated immunity, although this study did confirm post operative depression of these parameters. The significance of these changes is unclear but there is no evidence to support an immunological mechanism for either of these approaches being of benefit in clinical practice.

A new device for delayed hypersensitivity skin testing

A new device for assessment of delayed cutaneous hypersensitivity using seven standardized antigens (Multitest CMI) was compared to conventional intradermal testing with two recall antigens in 83 patients referred for nutritional support. Sixteen patients (19.3%) were anergic to Multitest CMI while four (4.8%) were anergic to conventional testing. Patients anergic to Multitest CMI had a higher complication (intraabdominal abscess, prolonged ileus, sepsis, pneumonia) than those who were immunocompetent by this test suggesting a group at greater risk. This interpretation is consistent with an increased specificity of Multitest CMI over conventional testing in the identification of clinically important anergy.

Some factors influencing the immunisation of sheep with irradiated Haemonchus contortus larvae

Over the last 6 years a number of experiments in which sheep were successfully immunised with 2 doses of 10 000 Haemonchus contortus larvae, irradiated at 60 krad in a gamma-source, have been reported by the authors. In this paper, the failure of such a regimen of immunisation, using the same strain of larvae, is reported together with an investigation of the possible causes. Technical errors were eliminated as a cause, on the grounds that the failure occurred in 2 separate laboratories using different 60Co sources, as was increased radiosensitivity of the continuously passaged strain of H. contortus as measured by the percentage development of irradiated larvae in 6 naive lambs. From experiments utilising 18 lambs and using both irradiated and normal larvae, it was postulated that the strain had lost its original degree of immunogenicity. Subsequently, in 2 experiments involving 27 lambs, it was shown that irradiation at 40 krad was completely successful in restoring immunogenicity and producing a degree of protection against challenge similar to that previously reported with 60 krad. It was concluded that, with the current strain of H. contortus, 60 krad is now too high a level of irradiation of larvae to produce a consistently high degree of protection against challenge.

Clinical benefits of telemetered electrograms in assessment of DDD function

The advent of telemetry of the endocardial electrogram is a new capability. It must be convenient to use if it is to gain acceptance. Our experience is still growing but already it is confirming information that was either deduced or previously only available by active invasive procedures. The potential value of the technology has only been touched upon in this presentation. We are convinced that it will grow and that its value will be further established as more physicians have an opportunity to use it and gain additional experience.

The abomasal histology of worm-free sheep given primary and challenge infections of Haemonchus contortus

The histological changes in the abomasal mucosa of pairs of worm-free ewes and lambs were compared at various stages after infection and reinfection with 350 Haemonchus contortus L3 per kg bodyweight. In terms of worm burdens the ewes were relatively resistant to reinfection compared with the lambs and the histological changes in the abomasum at most stages after infection were more marked in the adult animals. These included increases in the numbers of mast cells, globule leucocytes, eosinophils and IgA plasma cells in the mucosa.

Mannose-sensitive adherence of Escherichia coli to epithelial cells from women with recurrent urinary tract infections

The effect of D-mannose on adherence of 73 Escherichia coli strains to vaginal and buccal epithelial cells from women with recurrent urinary tract infections, and on agglutination of human and guinea pig erythrocytes was tested. Urinary, vaginal or anal isolates from women with such infections were used. Of the strains 66 (90 per cent) demonstrated adherence to epithelial cells. D-mannose inhibited completely the adherence of 25 strains (42 per cent) that adhered to vaginal cells and inhibited an additional 11 strains (18 per cent) by at least 50 per cent. Similar results were obtained with buccal cells. The inhibitory effect of D-mannose was similar regardless of the origin of the strains. Hemagglutination frequently was inhibited by D-mannose but no consistent association between hemagglutination, and epithelial cell adherence and the effect of D-mannose was observed. The results suggest that mannose-sensitive as well as mannose-resistant adhesins frequently mediate Escherichia coli adherence to vaginal epithelial cells, and may contribute to vaginal colonization and cystitis.

In vitro leukocyte endogenous mediator production is not impaired following surgical stress in moderately malnourished patients

Leukocyte endogenous mediator (LEM), a protein produced by phagocytizing cells, plays a critical role in the metabolic response to injury and infection. There is an important interaction between protein-calorie malnutrition and the capacity of cells to produce LEM, since severely malnourished or severely stressed individuals, have a reduced capacity to produce LEM. The leukocytes of 10 mildly to moderately malnourished patients undergoing elective major surgery, a moderate stress, had an intact ability to produce LEM on preoperative assessment. This ability was not affected by a 5-day postoperative period of hypocaloric nutrient intake despite a significant loss of body protein in one-half of the patients and a significant fall in serum protein concentrations. These results suggest a high biologic priority for LEM production during the metabolic response to injury and for infection.

Role of enzootic abortion and toxoplasmosis in an outbreak of abortion in a Scottish sheep flock

During 1978-79 there was an outbreak of abortion in a large sheep flock during which approximately 10 per cent of the breeding ewes aborted. Both Toxoplasma gondii and Chlamydia ovis (the agent of enzootic abortion of ewes) were considered to be involved. In the year following this outbreak (1979-80), 156 ewes (11.4 per cent) aborted and the majority of cases were diagnosed as enzootic abortion: only one case showed gross pathology typical of toxoplasmosis. Serology carried out on sera collected from ewes at the time of abortion and at two post abortion samplings demonstrated that large numbers of animals had high titres against enzootic abortion of ewes while the prevalence of sheep with titres against toxoplasmosis was relatively low. Following the introduction of control measures to reduce the spread of enzootic abortion of ewes, the abortion rate in 1980-81 fell to 2.2 per cent. A small-scale trial was carried out to investigate the prophylactic effect of long acting oxytetracycline against enzootic abortion of ewes when given to pregnant sheep three weeks before lambing. Results indicated that treatment reduced the number of abortions in comparison with untreated controls.