Mycobacterial infection in HIV seropositive and seronegative populations, 1987-93

BACKGROUND

Although the causes of the worldwide resurgence of tuberculosis are multifactorial, the HIV epidemic is believed to have had a central role. Control is further threatened by the emergence of multidrug-resistant tuberculosis.

METHODS

A retrospective evaluation was undertaken of trends in pulmonary and extrapulmonary culture positive mycobacterial pathology, and the prevalence of drug-resistant tuberculosis in both HIV seropositive and, presumptively, HIV seronegative patients receiving their clinical care at St Mary's Hospital, London. Five hundred and thirty eight patients (188 of whom were known to be HIV seropositive) with positive mycobacterial isolates between January 1987 and March 1993 were identified from laboratory records. These were cross referenced with drug surveillance records.

RESULTS

Overall, between 1987 and 1992 there was a progressive 3.5 fold increase in positive mycobacterial isolates and a 2.5 fold increase in patients with proven mycobacterial infection. This increase was greater within the HIV seropositive population. A total of 663 positive mycobacterial isolates was evaluated; the major pathogen identified was Mycobacterium tuberculosis (379 isolates, 57%). Three hundred and fourteen patients were diagnosed as having M tuberculosis, 49 of whom were HIV seropositive. M tuberculosis was predominantly isolated from the lung. Of 358 positive cultures for M tuberculosis (68 HIV seropositive, 290 presumptively HIV seronegative), only 27 isolates (7.6%), almost exclusively derived from presumed HIV seronegative patients, were resistant to either isoniazid, rifampicin, or both drugs together. No increases in drug-resistant isolates were observed over this period.

CONCLUSIONS

There has been a considerable increase in the incidence of tuberculosis in both HIV seronegative and seropositive populations during the study period. The emergence of drug-resistant tuberculosis was not observed.

Abnormalities of serum type III procollagen aminoterminal peptide in methotrexate-treated psoriatic patients with normal liver histology do not correlate with hepatic ultrastructural changes

In a previous study, it was shown that the serum levels of type III procollagen aminoterminal peptide (P3NP) were significantly greater in patients receiving methotrexate (MTX) treatment for psoriasis than in untreated control patients with psoriasis. Although levels were highest in patients with hepatic fibrosis and cirrhosis, serum P3NP concentrations in those patients with normal liver histology on light microscopy were also shown to be significantly higher than in controls. In the present study, liver biopsies from 22 such 'normal' patients were examined by electron microscopy, in order to determine whether P3NP levels correlated with ultrastructurally demonstrable fibrosis. Fibrosis in the perisinusoidal space of Disse was present in as many as 82% of biopsies. Although the prevalence of such fibrosis in psoriasis patients who have not received MTX is unknown, the high prevalence of Disse space fibrosis and of raised P3NP in MTX-treated patients suggests that MTX causes subtle liver damage in a majority of treated patients. However, we were unable to show a statistical correlation between P3NP and the degree of Disse space fibrosis.

Two conformations of the catalytic site in the aa3-type cytochrome c oxidase from Rhodobacter sphaeroides

Resonance Raman spectra of the carbon monoxy derivative of the aa3-type cytochrome c oxidase from Rhodobacter sphaeroides show two distinct Fe-CO stretching modes (519 and 493 cm-1) at room temperature. The frequency of the mode at 519 cm-1 coincides with that of other terminal oxidases at neutral pH. Two C-O stretching modes, one at 1966 cm-1 and one at 1955 cm-1, are also found. The splitting of the C-O stretching mode is consistent with the FTIR spectra of cytochrome c oxidases at cryogenic temperatures in which two different conformations (alpha and beta) of the catalytic site of the enzyme are present. The splitting of both the Fe-CO and C-O stretching modes under our conditions indicates that these two forms of the enzyme are also present at room temperature, and with the additional information on the Fe-CO modes provided here, a structural origin for the two forms may be postulated. The alpha-form has the same general structure of the active site as mammalian oxidase, a structure in which the copper atom that is the part of the Fe-CuB binuclear site interacts strongly with the bound CO. We postulate that the copper atom exerts a strong polar or steric effect on the heme-bound CO, resulting in either compression of the Fe-CO bond or distortion of the Fe-CO moiety.(ABSTRACT TRUNCATED AT 250 WORDS)

Rapid purification of wildtype and mutant cytochrome c oxidase from Rhodobacter sphaeroides by Ni(2+)-NTA affinity chromatography

A rapid and highly efficient method of purifying the aa3-type cytochrome c oxidase from Rhodobacter sphaeroides has been developed. This method relies upon a six-histidine affinity tag fused to the C-terminus of subunit I, which confers to the oxidase a high affinity for Ni(2+)-nitrilotriacetic acid (NTA) agarose. The histidine-tagged oxidase can be purified rapidly and with high yield by one affinity chromatography step, starting with solubilized membranes. The purified oxidase is > 95% pure and possesses structural and functional characteristics of the wildtype enzyme. The six-histidine tag can be easily added to pre-constructed site-directed mutants of subunit I, increasing the availability of purified cytochrome c oxidase mutants for biophysical and biochemical studies.

Growth performance, carcass composition, and pigmentation of broilers fed supplemental nickel

Two experiments were conducted to evaluate effects of supplemental Ni on growth performance, carcass composition, and pigmentation of broilers. In Experiment 1, female broilers (n = 120) were housed in individual cages from 21 to 49 d of age and fed a commercial finisher diet that contained 2.4 +/- .1 ppm Ni. Supplementation of this diet with 6 or 12 ppm NiCl2 did not affect growth performance or carcass composition. In Experiment 2, female broilers (n = 60) housed in individual cages were fed finisher diets with 44 or 77 ppm xanthophyll and 0 or 12 ppm supplemental NiCl2. Growth performance from 21 to 49 d of age was not altered by diet. At 49 d of age, serum xanthophyll concentration as well as amount of lutein and total xanthophylls in skin were higher (P < or = .01) in broilers fed 77 ppm xanthophyll. Supplemental NiCl2 decreased (P < or = .1) yellow color of carcasses from broilers fed 44 ppm xanthophyll and increased yellow color of carcasses from broilers fed 77 ppm xanthophyll. Abdominal fat yields and concentration of total xanthophylls in skin followed a similar pattern, suggesting that supplemental NiCl2 may have indirectly influenced pigmentation by altering fat deposition. These data indicated that an adequate level of Ni was present in the basal diet to promote optimal growth performance and carcass quality.

The effect of sterols and brefeldin A on protein degradation in UT-1 cells

UT-1 cells, a mutant Chinese hamster ovary (CHO) cell line induced to produce an abundance of the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), were used to determine the effects of sterols and brefeldin A on the degradation of this enzyme. Brefeldin A has been shown to cause retention of proteins in and relocation of proteins to the endoplasmic reticulum (ER). UT-1 cells were incubated with (a) sterols only (12 micrograms/ml cholesterol and 0.2 microgram/ml 25-hydroxycholesterol), (b) sterols and brefeldin A (0.5 microgram/ml), and (c) brefeldin A only. Western blot analysis showed that incubation with sterols and brefeldin A decreased HMGR levels more slowly than incubation with sterols alone over the first 24-36 h of incubation; however, the rates were not significantly different. By 48 h of incubation, HMGR had decreased to a level comparable to that found when cells were incubated in sterols only. Incubation with brefeldin A alone did not cause a decrease in HMGR over the same 48-h time period. HMGR was undetectable in parental CHO cells under all of the conditions described. Indirect immunofluorescence microscopy revealed a pattern of tight, perinuclear staining with sterol incubation. After 48 h in sterols, HMGR staining was uniformly decreased throughout the cytoplasm. This change in staining pattern is also observed during incubation of UT-1 cells with sterols and brefeldin A. Incubation for 48 h with brefeldin A alone had no effect on the tight perinuclear pattern originally observed. Diffuse, faint staining of CHO cells under all conditions served as a negative control. The results of these experiments indicated that brefeldin A, and therefore retention of proteins in the ER, does not interfere with the degradation of HMG CoA reductase. Despite the presence of brefeldin A, sterol-mediated dispersal and degradation of the crystalloid ER (CER) continued in UT-1 cells. Lack of brefeldin A sensitivity implied that the mechanism for CER dissolution was distinct from previously described mechanisms for ER to Golgi transport.

Platelet-derived growth factor-beta mRNA in human alveolar macrophages in vivo in asthma

Collagen deposition and myofibroblast proliferation beneath the epithelial basement membrane in patients with asthma is now increasingly recognized, although the molecular pathogenesis remains obscure. We have evaluated messenger ribonucleic acid (mRNA) expression of the profibrotic cytokine, platelet-derived growth factor-beta (PDGF-beta), in alveolar macrophages obtained following fibreoptic bronchoscopy and bronchoalveolar lavage in patients with asthma. Three subject groups were studied: 1) asthmatics using regular inhaled glucocorticoid medication (ASTST, n = 9), 2) asthmatics using intermittent inhaled beta 2-agonist therapy only (ASTBR, n = 10); 3) nonasthmatic control volunteers (n = 10). Alveolar macrophage mRNA was extracted and PDGF-beta mRNA quantified by reverse-transcriptase polymerase chain reaction (PCR) (RT-PCR) and expressed as the ratio to that of a control gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH). There were no significant differences in PDGF-beta mRNA expression between the groups, or between all asthmatic (n = 19) and control subjects. Furthermore, there was no correlation between alveolar macrophage PDGF-beta mRNA expression and airway spirometry, or duration of glucocorticoid usage or dose. Thus, in contrast to other fibrotic lung diseases, we found little evidence of enhanced expression of PDGF-beta mRNA in alveolar macrophages in clinically stable bronchial asthma.

Platelet-derived growth factor-beta mRNA in human alveolar macrophages in vivo in asthma

Collagen deposition and myofibroblast proliferation beneath the epithelial basement membrane in patients with asthma is now increasingly recognized, although the molecular pathogenesis remains obscure. We have evaluated messenger ribonucleic acid (mRNA) expression of the profibrotic cytokine, platelet-derived growth factor-beta (PDGF-beta), in alveolar macrophages obtained following fibreoptic bronchoscopy and bronchoalveolar lavage in patients with asthma. Three subject groups were studied: 1) asthmatics using regular inhaled glucocorticoid medication (ASTST, n = 9), 2) asthmatics using intermittent inhaled beta 2-agonist therapy only (ASTBR, n = 10); 3) nonasthmatic control volunteers (n = 10). Alveolar macrophage mRNA was extracted and PDGF-beta mRNA quantified by reverse-transcriptase polymerase chain reaction (PCR) (RT-PCR) and expressed as the ratio to that of a control gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH). There were no significant differences in PDGF-beta mRNA expression between the groups, or between all asthmatic (n = 19) and control subjects. Furthermore, there was no correlation between alveolar macrophage PDGF-beta mRNA expression and airway spirometry, or duration of glucocorticoid usage or dose. Thus, in contrast to other fibrotic lung diseases, we found little evidence of enhanced expression of PDGF-beta mRNA in alveolar macrophages in clinically stable bronchial asthma.

Angiotensin II as a risk factor for cyclosporin nephrotoxicity in patients with psoriasis

Abnormalities of the renin-angiotensin system after low-dose cyclosporin (5 mg/kg/day or less) have not been adequately defined in patients with normal kidneys. 27 patients with psoriasis were assessed before starting cyclosporin, after three months of cyclosporin (5 mg/kg/day or less) and then finally three months after finishing cyclosporin. On each occasion plasma renin activity (PRA), aldosterone, angiotensin II and atrial natriuretic peptide (ANP) were measured together with total renal blood flow (RBF), GFR and filtration fraction (FF) following an i.v. bolus injection of Tc-99m DTPA. Significant renal hemodynamic toxicity was defined as > 25% fall in RBF or > 20% fall in GFR. Using these criteria we identified 12 patients with hemodynamic toxicity (Group A) and 15 patients whose GFR and RBF did not fall significantly (Group B). In Group A a significant fall in GFR (p < 0.001) and reduction in renal blood flow (p < 0.04) were associated with significant rises in both ambulant and recumbent angiotensin II (p < 0.0005). PRA, aldosterone and ANP did not significantly alter. GFR partially recovered after withdrawal of cyclosporin although RBF remained significantly lower compared to initial values. In Group B there was no significant change in GFR or RBF although there was a reversible fall in FF (p < 0.02). There were no significant differences in angiotensin II, PRA, aldosterone or ANP. Circulating angiotensin II rises in patients who develop cyclosporin nephrotoxicity and may be responsible for mediating the hemodynamic effects.

The role of bronchoscopy in patients with HIV disease

Pulmonary involvement is a frequent feature of patients infected with the human immunodeficiency virus (HIV). Pneumocystis carinii pneumonia (PCP) is still the commonest AIDS defining diagnosis despite the advent of effective prophylaxis and antiretroviral treatment. Other pulmonary manifestations of AIDS, including tuberculosis, may pose a greater problem in the future. The clinical manifestations of HIV-disease are many and varied, and changing as the disease is modified by therapeutic interventions. With specific and increasingly effective treatments the need for definitive diagnosis is obvious. Fibreoptic bronchoscopy is a well established tool for the diagnosis of HIV-related pulmonary complications. This article aims to give an account on the use of bronchoscopy in a unit providing care for many HIV seropositive patients.

HIV-1 proviral DNA copy number in peripheral blood leucocytes and bronchoalveolar lavage cells of AIDS patients

In this study we have determined by polymerase chain reaction (PCR) the quantity of HIV-1 proviral DNA in cells obtained by bronchoalveolar lavage (BAL) from the lung of HIV-1+ individuals. This has been compared quantitatively with the proviral DNA in peripheral blood leucocytes (PBL) obtained simultaneously from the same patients. The mean HIV DNA copy number per 10(6) cells was 391 for PBL, with a range of 1-9000, and 2971 for BAL cells, with a range of < 1-70,000. The quantity of HIV DNA detected in BAL cells was higher than that detected in the corresponding PBL samples in 44 out of 78 (56%) individuals, whilst more HIV DNA was detected in the PBL compared with BAL cells in 14 out of 78 (18%) patients. In both BAL and PBL higher levels of HIV DNA were detected in the adherent (monocyte/macrophage) enriched cell populations compared with other non-adherent cells (leucocytes). A direct relationship between HIV DNA copy number and ability to recover infectious HIV progeny in vitro by co-cultivation with cord blood leucocytes was found for both PBL and BAL cells. Individuals known to be receiving azidothymidine treatment had a lower mean HIV DNA load in all cell fractions compared with those patients on no antiretroviral therapy.

The mortality of rheumatoid arthritis

OBJECTIVE

To determine the risk and causes of death and to quantify mortality predictors in patients with rheumatoid arthritis (RA).

METHODS

RA patients (n = 3,501) from 4 centers (Saskatoon n = 905, Wichita n = 1,405, Stanford n = 886, and Santa Clara n = 305) were followed for up to 35 years; 922 patients died.

RESULTS

The overall standardized mortality ratio (SMR) was 2.26 (Saskatoon 2.24, Wichita 1.98, Stanford 3.08, Santa Clara 2.18) and increased with time. Mortality was strikingly increased for specific causes: infection, lymphoproliferative malignancy, gastroenterologic, and RA. In addition, as an effect of the SMR of 2.26, the expected number of deaths was increased nonspecifically across all causes (except cancer), with a large excess of deaths attributable to cardiovascular and cerebrovascular diseases. Independent predictors of mortality included age, education, male sex, function, rheumatoid factor, nodules, erythrocyte sedimentation rate, joint count, and prednisone use.

CONCLUSION

Mortality rates are increased at least 2-fold in RA, and are linked to clinical severity.

Evidence for a Th1-like bronchoalveolar T-cell subset and predominance of interferon-gamma gene activation in pulmonary tuberculosis

Mycobacterium-specific human helper T-cell clones produce a Th1 pattern of cytokines in vitro: interferon-gamma (IFN-gamma) and interleukin-2 (IL-2), but little or no IL-4 or IL-5. To test the hypothesis that a similar Th1-like pattern of cytokine gene expression occurs in vivo in pulmonary tuberculosis we used in situ hybridization to detect cytokine mRNA expression by bronchoalveolar lavage cells from nine patients with microbiologically confirmed tuberculosis and nine control subjects. Because IFN-gamma may also originate from alveolar macrophages, simultaneous immunocytochemistry and in situ hybridization was applied to determine whether cytokine mRNA was localized to bronchoalveolar macrophages in addition to T-lymphocytes. When samples from patients with tuberculosis and control subjects were compared, there was a significant increase in numbers of IFN-gamma mRNA-positive BAL cells per 1,000 among patients with tuberculosis (p < 0.01). Differences between the two groups in the proportions of cells expressing IL-2, IL-4, or IL-5 mRNA were not significant. Expression of IFN-gamma mRNA by macrophages was detected (median, 14.3% of IFN-gamma mRNA-positive BAL cells). However, the majority of IFN-gamma mRNA expressing BAL cells were T-lymphocytes (median, 80.7%). Activation of Th1-like bronchoalveolar T-lymphocytes, together with production of IFN-gamma by alveolar macrophages, may contribute to the local cellular immune response in pulmonary tuberculosis.

Relation of HIV-I in bronchoalveolar lavage cells to abnormalities of lung function and to the presence of Pneumocystis pneumonia in HIV-I seropositive patients

BACKGROUND

HIV is present in bronchoalveolar lavage cells of some but not all HIV seropositive patients. Abnormalities of lung function have been described in such patients in the absence of clinically overt pneumonia or other respiratory infections. It is possible that the presence of HIV in alveolar macrophages could account for these abnormalities. It is also possible that the presence of HIV in alveolar macrophages contributes to immunosuppression and an increased incidence of opportunistic infections.

METHODS

This was a prospective study of 157 HIV seropositive patients requiring diagnostic bronchoscopy for investigation of new respiratory symptoms, chest radiograph abnormality, or pneumonic illness. Presence of HIV in bronchoalveolar lavage cells obtained at diagnostic bronchoscopy was determined by polymerase chain reaction to detect proviral DNA and in vitro cocultivation to detect productive virus infection. With these two techniques the presence or absence of HIV in bronchoalveolar lavage was compared with the presence of abnormalities of lung function or presence of Pneumocystis pneumonia.

RESULTS

HIV was detected in bronchoalveolar lavage cells in 65% of patients by means of the polymerase chain reaction and 59% with cocultivation. With both methods of detection there was no association between the presence or absence of HIV and the presence of Pneumocystis pneumonia; nor was there a relation between the presence of HIV and abnormalities of lung function.

CONCLUSION

The presence of HIV in bronchoalveolar lavage cells does not predispose to an increased incidence of Pneumocystis pneumonia; nor does it contribute to abnormalities of lung function.