TonB-dependent iron supply in Salmonella by alpha-ketoacids and alpha-hydroxyacids

A range of structurally diverse alpha-ketoacids and alpha-hydroxyacids promoted the growth of isolates of Salmonella serovars S. typhimurium, S. enteritidis, S. agona, S. paratyphi and S. stanleyville in iron restricted conditions in the absence of functional siderophores. Growth stimulation, observed both in cross-feeding tests on solid medium and in liquid cultures, and uptake of 55Fe in the presence of alpha-ketoisocaproic acid, were TonB dependent in S. typhimurium. In this respect the mechanism is distinct from a previously described Serratia marcescens system (sfuABC); the presence of the cloned sfuABC genes mediated tonB-independent uptake by S. typhimurium of iron complexed with alpha-ketoacids.

Oral immunization of interleukin-4 (IL-4) knockout mice with a recombinant Salmonella strain or cholera toxin reveals that CD4+ Th2 cells producing IL-6 and IL-10 are associated with mucosal immunoglobulin A responses

Mucosal immunoglobulin A (IgA) responses are often associated with Th2-type cells and derived cytokines, and interleukin-4 (IL-4) knockout (IL-4-/-) mice with impaired Th2 cells respond poorly to oral antigens. However, we have noted that IL-4-/- mice have normal mucosal IgA levels, which led us to query whether different oral delivery systems could elicit mucosal immunity. Two oral regimens were used: (i) a live recombinant Salmonella strain which expresses fragment C (ToxC) of tetanus toxin, and (ii) soluble tetanus toxoid (TT) with cholera toxin (CT) as an adjuvant. Oral immunization of IL-4-/- mice with recombinant Salmonella vaccine expressing ToxC induced brisk mucosal IgA and serum IgG (mainly IgG2a) anti-TT antibody responses. TT-specific CD4+ T cells from spleen or Peyer's patches produced gamma interferon, indicative of Th1 responses; however, IL-6 and IL-10 were also seen. Oral immunization of IL-4-/- mice with TT and CT induced weak mucosal IgA to TT; however, brisk IgA anti-CT-B responses and CT-B-specific CD4+ T cells producing IL-6 and IL-10 were also noted. These results show that although IL-4-dependent antibody responses are impaired, mucosal IgA responses are induced in IL-4-/- mice. These result suggest that certain cytokines, i.e., IL-6 and IL-10 from Th2-type cells, play an important compensatory role in the induction and regulation of mucosal IgA responses.

A somatically mutated human antiganglioside IgM antibody that induces experimental neuropathy in mice is encoded by the variable region heavy chain gene, V1-18

IgM paraproteins associated with autoimmune peripheral neuropathy and anti-Pr cold agglutinins react with sialic acid epitopes present on disialylated gangliosides including GD1b, GT1b, GQ1b, and GD3. A causal relationship between the paraprotein and the neuropathy has never been proven experimentally. From peripheral blood B cells of an affected patient, we have cloned a human hybridoma secreting an antidisialosyl IgM mAb, termed Ha1, that shows identical structural and functional characteristics to its serum counterpart. Variable region analysis shows Ha1 is encoded by the same VH1 family heavy chain gene, V1-18, as the only other known anti-Pr antibody sequence and is somatically mutated, suggesting that it [correction of is] arose in vivo in response to antigenic stimulation. In the rodent peripheral nervous system, Ha1 immunolocalizes to dorsal root ganglia, motor nerve terminals, muscle spindles, myelinated axons, and nodes of Ranvier. After intraperitoneal injection of affinity-purified antibody into mice for 10 d, electrophysiological recordings from the phrenic nerve-hemidiaphragm preparation demonstrated impairment of nerve excitability and a reduction in quantal release of neurotransmitter. These data unequivocally establish that an antidisialosyl antibody can exert pathophysiological effects on the peripheral nervous system and strongly support the view that the antibody contributes to the associated human disease.

Regulation of mucosal and systemic antibody responses by T helper cell subsets, macrophages, and derived cytokines following oral immunization with live recombinant Salmonella

We have assessed regulatory Th cell and cytokine responses in mice after oral immunization with recombinant Salmonella (BRD 847) expressing fragment C of tetanus toxoid, since little information is available to explain how these vectors induce mucosal IgA responses. A single dose of BRD 847 elicited serum IgG2a and mucosal IgA anti-tetanus toxoid Ab responses. To assess Th1-and Th2-type responses, CD4+ T cells from Peyer's patches and spleen were restimulated in vitro, and cytokine-specific ELISPOT, ELISA, and reverse transcriptase-PCR assays were used to assess cytokine patterns. CD4+ T cells produced IFN-gamma and IL-2 as well as IL-10, but not IL-4 or IL-5. Although IL-6 was elevated, further purification of cells from in vitro cultures into CD4+ Mac-1- T cells and Mac-1+ CD4- cells revealed that only the latter cell population had consistently elevated IL-6 gene expression, whereas both sorted populations exhibited increased IFN-gamma and IL-10 gene expression. Thus, orally administered recombinant Salmonella expressing fragment C of tetanus toxoid elicited dominant Ag-specific Th1-type responses together with Th2-type cells producing IL-10 in both mucosal and systemic tissues. Macrophages producing IL-6 were also evident. Our results are consistent with the suggestion that Ag-specific Th1 cells and their derived cytokines, IFN-gamma and IL-2, and Th2-derived IL-10 together with IL-6 produced by macrophages provide important signals for the development of mucosal IgA and serum IgG subclass responses in the absence of preferential expression of Th2 cytokines IL-4 and IL-5.

Regulation of mucosal and systemic antibody responses by T helper cell subsets, macrophages, and derived cytokines following oral immunization with live recombinant Salmonella

We have assessed regulatory Th cell and cytokine responses in mice after oral immunization with recombinant Salmonella (BRD 847) expressing fragment C of tetanus toxoid, since little information is available to explain how these vectors induce mucosal IgA responses. A single dose of BRD 847 elicited serum IgG2a and mucosal IgA anti-tetanus toxoid Ab responses. To assess Th1-and Th2-type responses, CD4+ T cells from Peyer's patches and spleen were restimulated in vitro, and cytokine-specific ELISPOT, ELISA, and reverse transcriptase-PCR assays were used to assess cytokine patterns. CD4+ T cells produced IFN-gamma and IL-2 as well as IL-10, but not IL-4 or IL-5. Although IL-6 was elevated, further purification of cells from in vitro cultures into CD4+ Mac-1- T cells and Mac-1+ CD4- cells revealed that only the latter cell population had consistently elevated IL-6 gene expression, whereas both sorted populations exhibited increased IFN-gamma and IL-10 gene expression. Thus, orally administered recombinant Salmonella expressing fragment C of tetanus toxoid elicited dominant Ag-specific Th1-type responses together with Th2-type cells producing IL-10 in both mucosal and systemic tissues. Macrophages producing IL-6 were also evident. Our results are consistent with the suggestion that Ag-specific Th1 cells and their derived cytokines, IFN-gamma and IL-2, and Th2-derived IL-10 together with IL-6 produced by macrophages provide important signals for the development of mucosal IgA and serum IgG subclass responses in the absence of preferential expression of Th2 cytokines IL-4 and IL-5.

Altered glomerular permselectivity to neutral dextrans and heteroporous membrane modeling in human pregnancy

Hyperfiltration precedes renal function loss in several nephropathies. Animal studies suggest this may be due to accompanying increases in transglomerular capillary hydrostatic pressure difference (delta P) and/or altered glomerular processing of macromolecules. Renal hemodynamics increase strikingly in human pregnancy. To test the hypothesis that these alterations are not potentially harmful, clearances of inulin, p-aminohippurate, and neutral dextrans were measured at 16- and 36-wk gestation, then 4 mo postpartum, in 11 normotensive women. Results were analyzed using two computer modeling programs. Glomerular filtration rate and renal plasma flow (RPF) were markedly elevated in early and late pregnancy (135 +/- 6 and 895 +/- 53 and 135 +/- 6 and 754 +/- 32 ml/min, respectively, vs. 87 +/- 7 and 520 +/- 17 ml/min postpartum). Gestational hyperfiltration was primarily due to RPF increments with a minor contribution from decrements in capillary oncotic pressure. Fractional dextran clearances (particularly the smaller dextrans, 30-39 A radii) were lower in early pregnancy, decreasing further in late pregnancy. There was no evidence of increased delta P and alterations in glomerular membrane porosity resolved postpartum. These data provide a database by which to study effects of pregnancy on chronic renal disease.

Violence among psychiatric in-patients at an Interim Secure Unit: changes in pattern over a two-year period

A retrospective study of recordings of all violent episodes among in-patients requiring restraint was undertaken over a two-year period during which the nature of admissions to the unit changed to an increase in mentally abnormal offenders (those admitted through the criminal justice system and detained under criminal sections of the Mental Health Act). It was found that those detained under criminal sections were less likely to be aggressive, were of relatively older age and less likely to repeat the violence than their mentally ill counterparts detained under civil sections. In addition to the past history of violence, verbally abusive behaviour was the best predictor of subsequent physical aggression though only a minority of patients displaying serious physical assault showed verbally abusive behaviour. Deterioration in mental health and staff-patient interaction were seen as major contributory factors to aggression which will also explain a greater degree of aggression directed towards the staff. Further comparative analysis of aggressive behaviour of mentally ill patients detained under civil sections and mentally abnormal offenders is warranted.

The management of post-cardiac transplantation coronary artery disease

OBJECTIVE

Allograft coronary artery disease remains the single greatest limitation to long term survival after cardiac transplantation. It is peculiarly aggressive in its behavior and diffuse in its nature. The role of conventional approaches to coronary artery revascularisation were studied in a selected group of cardiac transplant recipients.

METHODS

Of the 557 patients undergoing cardiac transplantation at our unit between January 1979 and December 1993, all were screened for the development of allograft coronary artery disease routinely after 2 years and yearly thereafter or after 4 years. Twenty patients with allograft coronary artery disease were considered suitable for treatment by conventional means 17 of whom had undergone transplantation for ischaemic cardiomyopathy and the others for dilating cardiomyopathy. Percutaneous transluminal coronary angioplasty was performed in 18, 25-103 months after transplantation (mean 60 months) all of whom had severe proximal stenoses and reversible defects on perfusion scans. None suffered chest pain. Coronary artery bypass grafting was performed in 5, 95-105 months after transplantation (mean 101 months) 2 of whom had post-infarction unstable angina and 3 had severe triple vessel disease, dyspnoea, and perfusion abnormalities.

RESULTS

The primary success rate for PTCA was 84% (16/19). Two lesions restenosed and 3 patients had progressive disease which necessitated coronary revascularisation. No patient died. Of the 5 patients undergoing coronary artery surgery 2 died perioperatively, one from acute left ventricular failure and one from acute rejection. All 18 survivors have improved perfusion scans. Following surgery, all survivors had improvement in dyspnoea and relief of angina. Five late deaths a mean of 89 months after transplantation were from coronary artery disease (4) and lung malignancy (1).

CONCLUSIONS

Revascularisation by PTCA and CABG is feasible and successful in selected cardiac transplant recipients. Further study is required to determine the effect of revascularisation on prognosis.

Cardiac outcome after peripheral vascular surgery. Comparison of general and regional anesthesia

BACKGROUND

Despite evidence that regional anesthesia may be associated with fewer perioperative complications than general anesthesia, most studies that have compared cardiac outcome after general or regional anesthesia alone have not shown major differences. This study examines the impact of anesthetic choice on cardiac outcome in patients undergoing peripheral vascular surgery who have a high likelihood of associated coronary artery disease.

METHODS

Four hundred twenty-three patients, between 1988 and 1991, were randomly assigned to receive general (n = 138), epidural (n = 149), or spinal anesthesia (n = 136) for femoral to distal artery bypass surgery. All patients were monitored with radial artery and pulmonary artery catheters. Postoperatively, patients were in a monitored setting for 48-72 h and had daily electrocardiograms for 4-5 days and creatine phosphokinase/isoenzymes every 8 h x 3, then daily for 4 days. Cardiac outcomes recorded were myocardial infarction, angina, and congestive heart failure.

RESULTS

Baseline clinical characteristics were not different between anesthetic groups. Overall, the patient population included 86% who were diabetic, 69% with hypertension, 36% with a history of a prior myocardial infarction, and 41% with a history of smoking. Cardiovascular morbidity and overall mortality were not significantly different between groups when analyzed by either intention to treat or type of anesthesia received. In the intention to treat analysis, incidences of cardiac event or death for general, spinal, and epidural groups were 16.7%, 21.3%, and 15.4%, respectively. The absolute risk difference observed between general and all regional anesthesia groups for cardiac event or death was -1.6% (95% confidence interval -9.2%, 6.1%) This reflected a nonsignificant trend for lower risk of postoperative events with general anesthesia.

CONCLUSIONS

The choice of anesthesia, when delivered as described, does not significantly influence cardiac morbidity and overall mortality in patients undergoing peripheral vascular surgery.

Excellent outcome of cardiac transplantation using domino donor hearts

OBJECTIVE

Domino cardiac transplantation affords flexible and optimal organ utilization, provides hearts unaffected by brain death, allows prospective tissue matching, and subsequent transplantation with short allograft ischemic times. A retrospective review of our experience with domino cardiac transplantation has been made.

METHODS

Seventy-two of 119 patients who underwent heart-lung transplantation from 1988 on served as domino cardiac donors (40 males, 32 females; mean age of 32 years; mean weight of 51 kg). The domino donor diagnoses were cystic fibrosis (n = 47), bronchiectasis (n = 9), primary pulmonary hypertension (n = 6), emphysema (n = 7), pulmonary fibrosis (n = 2) and Eisenmenger's syndrome (n = 1). Forty-seven domino hearts were transplanted at our institution and 25 were exported to other centres in the United Kingdom. The 72 domino cardiac recipients were 62 males and 10 females, mean age of 47 years, mean weight of 60 kg, with ischemic heart disease (n = 32), cardiomyopathy (n = 36) and other conditions (n = 4).

RESULTS

There were four deaths (5.6%) at less than 30 days (2 from multiple organ failure, 1 from primary allograft failure and 1 from acute rejection). Actuarial survival estimates and 1 and 5 years were 77 +/- 5.2% nd 69 +/- 6.3%, respectively. This compared favourably with survival data obtained in 234 non-domino cardiac recipients. In the patients transplanted at Papworth, there was no difference in the incidence of rejection (0.6 +/- 0.05 versus 0.7 +/- 0.03 events per 100 patient days for the first 12 months) or in the freedom from graft atherosclerosis (74 +/- 3% versus 70 +/- 3% at 5 years) between the domino and non-domino groups.

CONCLUSIONS

The use of domino hearts donated by recipients of heart-lung transplants is beneficial and is associated with an excellent early and longer-term outcome.

Mucosal and systemic immunogenicity of a recombinant, non-ADP-ribosylating pertussis toxin: effects of formaldehyde treatment

The effect of formaldehyde treatment on the mucosal and systemic immunogenicity of the genetically detoxified pertussis toxin (PT-9K/129G) was investigated. Groups of BALB/c were immunized intranasally (i.n.) or subcutaneously (s.c.) with untreated, lightly formaldehyde treated (LFT) or heavily formaldehyde treated (HFT) recombinant pertussis toxin (PT) mutant, PT-9K/129G. Intranasal immunization with native PT-9K/ 129G induced significant levels of anti-toxin antibodies in serum and IgA anti-toxin responses in nasal and lung lavages of these mice. Similar local and systemic responses were observed following intransal immunization with LFT toxin. However, i.n. immunization with HFT toxin failed to induce a local IgA response and elicited a much diminished anti-toxin response in the serum. In contrast, the total antibody response following s.c. immunization was not significantly affected. In addition, i.n. immunization with native PT-9K/129G induced low but detectable levels of toxin neutralizing antibodies in the serum. These results show that native PT-9K/129G protein acts as a mucosal immunogen in mice and that this activity is greatly diminished by HFT of the protein.

Allergic bronchopulmonary mycosis caused by Fusarium vasinfectum

We present a case of allergic bronchopulmonary fusariosis (ABPF). This is the first case of allergic bronchopulmonary mycosis (ABPM) caused by Fusarium vasinfectum reported in the medical literature. The patient presented with a history and radiographic picture highly suggestive of allergic bronchopulmonary aspergillosis (ABPA), yet with negative ABPA serology results. The demonstration of a positive skin test and precipitins against F. vasinfectum, elevated serum IgG and IgE antibodies against F. vasinfectum, and a decline in total serum IgE with treatment clearly establish the diagnosis of ABPF. The diagnosis of ABPM caused by organisms other than Aspergillus represents an important consideration in patients who appear clinically to have ABPA but whose serology results do not confirm this diagnosis. As in ABPA, early diagnosis and appropriate therapy may be necessary in order to prevent progressive lung disease.

The relationship between heart rate variability and measures of body habitus

There is a well-recognized relationship between autonomic nervous system function and body habitus although few studies have addressed the role of the parasympathetic nervous system. A decrease in parasympathetic nervous-system-mediated heart rate variability in obesity may in part explain the mortality and morbidity that are associated with the obese state. We used multiple linear regression techniques to explore the relationship between measures of heart rate variability and anthropometric indices in 597 male participants in the Normative Aging Study. After adjustment for age and log10 heart rate, weight and body mass index were significant predictors of both the expiratory to inspiratory ratio (E/I ratio) and the difference between maximum and minimum heart rate (HRMax-Min). The abdomen-to-hip ratio and percentage body fat were not significant predictors of measures of heart rate variability. A one standard deviation change in the anthropometric index (weight, body mass index) resulted in a decrease in the E/I ratio of 0.010-0.014 and a decrease in the HRMax-Min of 0.486-0.715 beats/min. A change in the anthropometric index across the distribution (5-95 percentile) resulted in a decrease in the E/I ratio of 0.032-0.037 and a decrease in the HRMax-Min of 1.56-2.39 beats/min. These results indicate that heart rate variability and overall body size are correlated. This association could in part explain the mortality and morbidity that is associated with the obese state.

Allergic bronchopulmonary aspergillosis presenting with cough variant asthma and identifiable source of Aspergillus fumigatus

BACKGROUND

A 76-year-old man developed allergic bronchopulmonary aspergillosis initially presenting with cough variant asthma. Symptoms worsened after exposure to ground mulch which was an identifiable source of Aspergillus fumigatus. Symptoms improved after corticosteroids and avoidance measures were instituted.

OBJECTIVE

To report a case of allergic bronchopulmonary aspergillosis presenting as cough variant asthma with identifiable source of Aspergillus fumigatus.

METHODS

Single case report. Serum precipitating antibodies against Aspergillus fumigatus were tested using gel diffusion techniques. Total IgE, specific IgE, and IgG indices were measured by ELISA. Cutaneous reactivity to Aspergillus fumigatus was also tested.

RESULTS

Skin test and serum precipitating antibodies to Aspergillus fumigatus were positive. Precipitins were also detected between Aspergillus fumigatus and the mulch. Total serum IgE was 538 IU/mL (1290 ng/mL) which declined to 228 IU/mL (544 ng/mL) after corticosteroid therapy. IgE index = 1.10 and IgG index = 2.86.

CONCLUSION

Allergic bronchopulmonary aspergillosis can present as cough variant asthma. Identification of exacerbating factors such as sources of Aspergillus fumigatus are important in management.

Human tissue retrieval at post-mortem for musculoskeletal research

Laboratory experimentation must attempt to reduce animal involvement, and human cadaveric tissue can be a suitable alternative; however, this tissue is a potential biohazard, with the transmission of human immunodeficiency and hepatitis viruses presenting a very serious problem. In this paper we discuss how human tissue can be obtained at hospital post-mortem, and how it can then be stored and handled in a laboratory environment, focusing particularly on safety issues. We discuss the way in which the Department of Orthopaedic Surgery at Leicester University obtained human tissue for research into hip replacement. It is hoped that the article will serve as a 'blue-print' for other related research projects, where human tissue is required for experimentation.

The characterization of chromosomal rearrangements by a combined micro-FISH approach in a patient with myelodysplastic syndrome

We report the application of a combined strategy: chromosome microdissection, degenerate oligonucleotide primed-PCR, and reverse chromosome painting (micro-FISH), as well as forward chromosome painting, for the characterization of chromosomal rearrangements in a MDS patient with the karyotype 46,XX, -11, +r analyzed by G-banding. The karyotype was refined as 46,XX,der(2)t(2;11) (q35;?p13),der(11)dic r(11)(:p13-->q13::p13-->q13:). Our study demonstrated that the chromosome composition of a neoplasia can be identified more systematically and accurately using these combined molecular cytogenetic approaches. The DOP-PCR methodology modified is suitable for the practical application of micro-FISH on specimens prepared for routine banding analysis.

Multifactorial immunologic lung disease: a case report

BACKGROUND

Allergic asthma, allergic bronchopulmonary aspergillosis, and hypersensitivity pneumonitis are all forms of immunologically mediated lung disease. Recognition that more than one of these diseases may co-exist is necessary for proper patient management.

OBJECTIVE

To report a case of extrinsic (cat) asthma, allergic bronchopulmonary aspergillosis, hypersensitivity pneumonitis, and potentially fatal asthma. Immunologic mechanisms and treatment of these diseases are discussed.

METHODS

The study is a case report from a university hospital setting. Serum precipitating antibodies against avian antigens were measured using gel-diffusion technique. Serum IgE levels were measured and skin testing was performed to selected antigens.

RESULTS

The patient had positive cutaneous reactivity to cat antigen and Aspergillus. Serology for allergic bronchopulmonary aspergillosis and serum precipitating antibodies to finch extract were positive. Symptoms improved and prednisone requirements decreased after removal of finches.

CONCLUSION

A case of cat asthma, potentially fatal asthma, allergic bronchopulmonary aspergillosis, and hypersensitivity pneumonitis is presented. Early recognition and treatment of multifactorial immunologic lung disease with avoidance measures and use of corticosteroids can prevent progressive respiratory damage.

Iron supplying systems of Salmonella in diagnostics, epidemiology and infection

Well-known and newly characterised mechanisms, both endogenous and exogenous, for the uptake of iron by Salmonella are outlined, and their possible roles at various stages in infection are discussed. The contributions of a detailed understanding of iron supplying systems to techniques for diagnosis, epidemiology and disease management are described.