Secretion of IL-6, IL-8 and G-CSF by human endothelial cells in vitro in response to Staphylococcus aureus and staphylococcal exotoxins

The capacity of endothelial cells to produce and release cytokines (IL-6, IL-8 and G-CSF) in response to exposure to Staphylococcus aureus strains or staphylococcal exotoxins (alpha-toxin, enterotoxin A and TSST-1) was investigated. An endothelial cell culture model of human umbilical vein endothelial cells (HUVEC) was used. Five out of ten clinical isolates of S. aureus were found to induce cytokine production and release from endothelial cells. Four of the five isolates that induce cytokine release produced enterotoxin A, B, C, D and/or TSST-1, compared with two of those that did not induce release. Purified staphylococcal exotoxins (1 pg/ml-1 microg/ml) did not act as primary stimuli and induced no detectable cytokine secretion. When endothelial cells were prestimulated with IL-1beta or TNF alpha at a concentration of 1 ng/ml for 2 h, IL-1beta served as a potent primary stimulus for IL-6, IL-8 and G-CSF production, whereas TNF alpha did not induce any significant cytokine release during the subsequent 24 h. A further increase in IL-6 and G-CSF release, but not of IL-8, was observed when IL-1beta prestimulated cells were exposed to alpha-toxin or TSST-1. However, to potentiate cytokine production (IL-6 and IL-8) by SEA, both IL-1beta and the toxin had to be present simultaneously. Our data show that S. aureus, but not staphylococcal exotoxins, have the capacity to act as primary stimuli of endothelial cells and induce production and release of cytokines. IL-1beta may prime HUVEC to release IL-6, IL-8 and G-CSF prior to subsequent stimulation with staphylococcal exotoxins.

Economic evaluation of screening for prostate cancer: a randomized population based programme during a 10-year period in Sweden

Prostate cancer is a growing health problem representing considerable costs. Screening and early curative treatment may reduce morbidity and possibly prevent future escalating costs. However, population screening programmes are generally not well accepted at present due to uncertainty about whether screening for prostate cancer can result in reduced mortality. Evidence from large, randomized, controlled trials is still lacking. The objective of this study was to calculate clinical and economic consequences of general prostate cancer screening based on a limited screening trial in a Swedish community and a decision-tree model. A random selection of 1492 men (50-69 years) were invited to repeated screening in 1987. They have been examined every third year (four rounds). The other 7679 men in the population act as controls. The results show that the total incremental health care costs for prostate cancer will increase by 179 million SEK per year with screening compared to no-screening. The number of detected cases of localized cancer will increase by about 1000, which represents an additional cost of about 158,000 SEK per case. In conclusion, general screening for prostate cancer can be performed with a reasonable cost per detected localized cancer. Information on the long-term effect on life quality and cancer mortality is unknown.

Impact on health service costs of medical technologies used in management of prostatic cancer

The aim of the study was to calculate the direct costs for the management of prostatic cancer throughout the need for care period. The impact of new medical technologies was analysed on the basis of an earlier cost study. The records of all 128 men in a defined population who died in 1992-93 and had been diagnosed with prostatic adenocarcinoma were retrospectively reviewed from diagnosis to death. The median cost per case, SEK 86,400, was significantly lower than the average cost per case, SEK 135,000, largely because of a few high-cost patients (in 20% of cases the cost exceeded SEK 250,000). Analysis of cost distribution throughout the need for care period showed that about 84% of the total cost per case was incurred during the the 3 years up to death. Estimated total direct care costs due to prostatic cancer in Sweden in the mid-1980s and early 1990s rose from approx. SEK 550 million to approx. SEK 780 million (1993 prices).

Community-acquired pneumonia in adults

Efforts to reduce hospitalization or the length of stay are common topics in papers published last year. Chlamydia pneumoniae is now recognized worldwide as a common pathogen in community-acquired pneumonia. A great variation in the frequency of various pathogens is found in different countries, stressing the importance of ascertaining the aetiological and epidemiological situation in each respective country.

Antibody response in Staphylococcus aureus septicaemia--a prospective study

Formation of serum antibodies against alpha-toxin, teichoic acid and lipase was followed in 63 patients with Staphylococcus aureus septicaemia in 240 consecutive serum samples. Control subjects comprised 23 patients with septicaemia due to other causes and 21 febrile patients without septicaemia. An antibody response against alpha-toxin, measured by ELISA, was most common (40%) in the initial serum, but antibody to teichoic acid was present in the highest number of positive patients (60%) when samples were drawn between 0 and 30 days: 74% of the patients showed a positive antibody response to at least one of the three antigens. When complicated versus uncomplicated septicaemia was compared (samples taken 8-14 days), 14 (45%) of 31 patients had a positive response against alpha-toxin versus 12 (75%) of 16, against teichoic acid 16 (51%) of 31 versus 12 (75%) of 16 and against lipase 15 (48%) of 31 versus 8 (50%) of 16. Patients with low initial antibody levels displayed a poorer antibody response than those with higher initial antibody levels. This phenomenon was observed with all three antigens, but was most pronounced with alpha-toxin. The initial antibody levels may predict the antibody response during the course of the disease. ELISA titres against alpha-toxin correlated (r=0.87) with biological neutralising activity of the antisera. The results may indicate a biological role of serum antibodies in staphylococcal septicaemia.

Evaluation of Alcaligenes eutrophus cells as an NADH regenerating catalyst in organic-aqueous two-phase system

A soluble NAD-dependent hydrogenase contained in Alcaligenes eutrophus was evaluated as a coenzyme regenerating catalyst in an organic-aqueous two-phase (predominantly organic) system. The horse-liver alcohol-dehydrogenase (HLADH) catalyzed reduction of cyclohexanone to cyclohexanol was used as a model reaction. The impact of different solvents (selected to span a large variety of principal properties) on the stability and activity of the HLADH, using substrate-driven regeneration, was studied. Solvents suitable for the HLADH were then selected for an evaluation of the hydrogenase-driven coenzyme regeneration. Hydrophobic solvents such as heptane, toluene, and 1,1,1-trichloroethane were found to be suitable for the coupled reactions catalyzed by HLADH and hydrogenase. Nonimmobilized cells, permeabilized with cetyl-trimethyl-ammonium bromide, were the most efficient preparation for the regeneration of NADH. The use of this preparation in heptane (10% water) was optimized with respect to the yield obtained in the HLADH-catalyzed reduction of cyclohexanone. Using the optimized conditions, yields of 99% cyclohexanol were obtained.

Developmental adaptation of rat nociceptive withdrawal reflexes after neonatal tendon transfer

Nociceptive withdrawal reflexes (NWRs) were studied in adult rats in which the movement patterns produced by single muscles had been altered by neonatal tendon transfer. NWRs evoked by cutaneous noxious mechanical and thermal (CO2-laser) stimulation were recorded using electromyography in a decerebrate spinal preparation. The sensitivity distribution within the receptive fields of the NWRs of the extensor digitorum longus and the peronei muscles exhibited changes corresponding to the altered movement patterns. No detectable change of NWRs was found in normal muscles whose receptive fields overlapped that of the modified muscle. Furthermore, NWRs of muscles that regained an essentially normal function after neonatal tendon transfer did not differ from normal. It is proposed that a developmental experience-dependent mechanism, which takes into account the hindlimb movement pattern caused by contraction of single muscles, underlies the functionally adapted organization of adult NWRs.

Bottle-blowing in hospital-treated patients with community-acquired pneumonia

A study was carried out to determine whether bottle-blowing has any positive effects in patients with pneumonia. In a prospective open study 145 adults with untreated community-acquired pneumonia requiring hospitalization were randomized to early mobilization (group A), to sit up and take 20 deep breaths on 10 occasions daily (group B), or to sit up and to blow bubbles in a bottle containing 10 cm water through a plastic tube 20 times on 10 occasions daily (group C). Peak expiratory flow (PEF), vital capacity (VC), forced expiratory volume in 1 sec (FEV1) and serum concentration of C-reactive protein (CRP) were determined on admission, and on days 4 and 42. Fever duration and hospital stay were recorded. In a subset of 16 patients, single breath diffusion capacity of carbon monoxide was measured on 3 occasions. The patients in group A were hospitalized for a mean of 5.3 days, group B for 4.6 days and group C for 3.9 days. Treatment was a significant factor (p = 0.037) in a Cox regression model, with group C significantly better than group A (p = 0.01). The number of days with fever was 2.3, 1.7 and 1.6 in groups A, B and C respectively. These differences were not significant (p = 0.28). No significant differences were found between the groups regarding CRP, PEF, VC, FEV1, or diffusion capacity. Intensive bottle-blowing shortens the hospital stay in patients with pneumonia. The underlying mechanism is not clear.

Developmental adaptation of withdrawal reflexes to early alteration of peripheral innervation in the rat

1. In adult decerebrate spinal rats whose plantar nerves (PLN) had been transected at either postnatal day 1 (P1) or P21 the nociceptive withdrawal reflexes (NWR) of musculi extensor digitorum longus (EDL), peroneus longus (PER) and semitendinosus (ST) were characterized with respect to receptive field (RF) organization, magnitude and time course, using electromyography. Thermal (short CO2 laser pulses) and mechanical (calibrated pinch) stimulation were used. The innervation patterns in normal and lesioned adult rats were assessed by acute nerve lesions. 2. The spatial organization of the mean mechano- and thermonociceptive RFs of all the muscles studied was similar to normal in both P1- and P21-lesioned rats, although in some P21-lesioned rats atypical EDL RFs were encountered. 3. In P1-lesioned rats thermo-NWR of PER and EDL had normal magnitudes, while mechano-NWR were reduced. In P21-lesioned rats both thermo- and mechano-NWR of these muscles had reduced magnitudes. Except for thermo-NWR of ST in P1-lesioned rats, which were increased, NWR of ST had normal magnitudes in both P1- and P21-lesioned rats. The time course of thermonociceptive NWR of the muscles studied were near normal in both P1- and P21-lesioned rats. 4. Acute nerve lesions in adult P1-lesioned rats revealed an essentially abolished contribution to NWR from the PLN. Instead, the contribution to NWR from other hindpaw nerves, such as the superficial and deep peroneal nerves, was dramatically increased. By contrast, in P21-lesioned rats, the regenerated PLN contributed significantly to the NWR. 5. It is concluded that despite profound alterations of plantar hindpaw innervation induced by early PLN transection the cutaneous nociceptive input to NWR attained an essentially normal spatial organization. An experience-dependent mechanism is suggested to be instrumental in adapting the reflex connectivity to the peripheral innervation.

Postnatal development of the nociceptive withdrawal reflexes in the rat: a behavioural and electromyographic study

1. The postnatal development of nociceptive withdrawal reflexes was studied. In awake intact rats, forelimb, hindlimb and tail reflexes were recorded on videotape. In decerebrate spinal rats, electromyography (EMG) was used to record nociceptive withdrawal reflexes in musculi extensor digitorum longus (EDL), peronei, gastrocnemius-soleus (G-S) and biceps posterior-semitendinosus (BP-ST). Thermal (short-lasting CO2 laser pulses) and mechanical stimulation were used. 2. In adults, nociceptive withdrawal reflexes were typically well directed and reflex pathways to single hindlimb muscles had functionally adapted receptive fields. By contrast, at postnatal day (P) 1-7, the nociceptive withdrawal reflexes were often inappropriate, sometimes producing movements towards the stimulation, and EMG recordings revealed unadapted variable receptive fields. With increasing age, the nociceptive withdrawal reflexes progressively became well directed, thus producing localized withdrawal. Both withdrawal movements and spatial organization of the receptive fields were adult-like at P20-25. 3. Up to P25, reflex thresholds were more or less constant in both intact awake rats and spinal decerebrate rats, except in G-S in which no nociceptive withdrawal reflexes were evoked from P20 on. After P25, mechanical, but not thermal, thresholds increased dramatically. 4. EMG recordings revealed that during the first three postnatal weeks, the latency of the CO2 laser-evoked nociceptive withdrawal reflexes decreased significantly in peronei and BP-ST, but not in EDL, and thereafter increased significantly in peronei, BP-ST and EDL. The magnitude of the nociceptive withdrawal reflexes in these muscles increased markedly between P7 and P20 and showed little change thereafter. 5. Possible mechanisms underlying the postnatal tuning of the nociceptive withdrawal reflexes are discussed.

Serum antibody response to Staphylococcus aureus enterotoxins and TSST-1 in patients with septicaemia

The prevalence of enterotoxins and toxic shock syndrome toxin (TSST-1) production in strains isolated from patients with Staphylococcus aureus septicaemia, and the serum antibody response in relation to toxin production in vitro of each isolate, were investigated. Among 63 strains of S. aureus isolated from the blood of patients with septicaemia, 51 from patients with superficial wounds and 49 from nasal carriers, 50-60% produced at least one of the enterotoxins A-D or TSST-1. The most frequent toxins produced were enterotoxins A and C and TSST-1. Among the 63 patients with staphylococcal septicaemia, 51 (81%) had a significant rise or a high antibody titre, or both, to at least one of the toxins. A positive serological response to toxin A was found in 78%, to enterotoxin B in 83%, to enterotoxin C in 80%, to enterotoxin D in 86% and to TSST-1 in 92% of the patients from whom the isolated strain produced the respective toxin. Antibodies against enterotoxins A, B, C and D and TSST-1 were also seen in 35%, 16%, 32%, 59% and 10%, respectively, in patients infected by strains that did not produce the specific toxin. Immunological cross-reactions between the toxins were demonstrated both in hyperimmune sera obtained from rabbits and in patients' sera, particularly between enterotoxins B and C. It is concluded that these potent toxins with superantigenic properties are produced in vivo during S. aureus septicaemia. No differences with regard to enterotoxin or TSST-1 production or antibody response were noted between patients with complicated versus uncomplicated septicaemia.

Dynamics of blood cytokine concentrations in patients with bacteremic infections

Cytokines play a major role in the pathophysiology of sepsis and septic shock. Using enzyme immunoassays the acute serum levels of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), granulocyte-colony stimulating factor (G-CSF), interleukin-8 (IL-8), and leukemia inhibitory factor (LIF) were investigated in 90 patients with positive blood cultures and clinical signs of infection. In 27 patients samples were obtained on admission, after 1, 4, 12, 18, and 24 h, and then daily. The acute serum levels of IL-6, TNF-alpha, G-CSF, and IL-8 were significantly higher among patients with severe sepsis. Patients with Gram-negative infection had significantly higher levels of TNF-alpha on admission than did patients with Gram-positive infections (p = 0.0008). The levels of IL-6, G-CSF and, to some extent, TNF-alpha decreased rapidly in survivors within the first 24 h of admission to hospital and institution of treatment. LIF was detected in 8/90 in both survivors and nonsurvivors.

Diagnostic value of blood cytokine concentrations in acute pneumonia

BACKGROUND

The role of cytokines in the pathogenesis of pneumonia is still poorly understood. In a previous study the diagnostic value of measuring blood concentrations of interleukin 6 and interferon gamma was established. In the present study the value of blood concentrations of interleukin 8, granulocyte-colony stimulating factor, and lactoferrin as markers of bacteraemic pneumonia is evaluated.

METHODS

The circulating concentrations of interleukin 8 (IL-8), granulocyte-colony stimulating factor (G-CSF), and lactoferrin were measured in 14 patients with bacteraemic pneumococcal pneumonia and 49 patients with atypical pneumonia or influenza A infection using enzyme immunoassays.

RESULTS

Serum G-CSF concentrations were higher in the group with bacteraemic pneumococcal pneumonia, and G-CSF values correlated with the white blood cell count and levels of C-reactive protein (CRP). The levels of IL-8 were higher in the group with bacteraemic pneumococcal pneumonia than the groups with Chlamydia pneumonia, Legionella pneumonia, or influenza A infection, but there was no difference when compared with the group with Mycoplasma pneumonia. A white blood cell count of > 15 x 10(9)/l was highly suggestive of bacteraemic pneumonia. The concentrations of lactoferrin were raised in all groups except those with influenza A infection, but no difference was found between the different aetiological groups. A correlation was found between lactoferrin and white blood cell counts.

CONCLUSIONS

Serum G-CSF and IL-8 concentrations are potential markers of bacteraemic pneumonia.

A survey of spinal dorsal horn neurones encoding the spatial organization of withdrawal reflexes in the rat

The withdrawal reflex pathways to hindlimb muscles have an elaborate spatial organization in the rat. In short, the distribution of sensitivity within the cutaneous receptive field of a single muscle has a spatial pattern that is a mirror image of the spatial pattern of the withdrawal of the skin surface ensuing on contraction in the respective muscle. In the present study, a search for neurones encoding the specific spatial input-output relationship of withdrawal reflexes to single muscles was made in the lumbosacral spinal cord in halothane/nitrous oxide-anaesthetized rats. The cutaneous receptive fields of 147 dorsal horn neurones in the L4-5 segments receiving a nociceptive input and a convergent input from A and C fibres from the hindpaw were studied. The spatial pattern of the response amplitude within the receptive fields of 118 neurones was quantitatively compared with those of withdrawal reflexes to single muscles. Response patterns exhibiting a high similarity to those of withdrawal reflexes to single muscles were found in 27 neurones located in the deep dorsal horn. Twenty-six of these belonged to class 2 (responding to tactile and nociceptive input) and one belonged to class 3 (responding only to nociceptive input). None of the neurones tested (n = 20) with reflex-like response patterns could be antidromically driven from the upper cervical cord, suggesting that they were spinal interneurones. With some overlap, putative interneurones of the withdrawal reflexes to the plantar flexors of the digits, the plantar flexors of the ankle, the pronators, the dorsiflexors of the ankle, and a flexor of the knee, were found in succession in a mediolateral direction.(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin-6, C-reactive protein, lactoferrin and white blood cell count in patients with S. aureus septicemia

In a prospective study of 65 patients with S. aureus septicemia, the clinical value of measuring serum IL-6 and lactoferrin levels was assessed and compared with CRP levels and WBC count. 20/65 (31%) patients had a CRP value < or = 100 mg/l on admission and 10 (50%) and 11 (55%) of these had serum levels of IL-6 > 100 pg/ml or lactoferrin > 2.0 mg/l, respectively. 41/64 (64%) patients had a WBC count < or = 15.0 x 10(9)/l and the corresponding figures for increased IL-6 and lactoferrin values were 29 (71%) and 21 (51%) patients, respectively. The high concentrations of IL-6 and lactoferrin on admission decreased rapidly during the hospital stay, better reflecting the clinical course than CRP and WBC count. Patients with endocarditis showed higher IL-6 levels and body temperatures both on admission and during the first days of hospitalization compared with patients without endocarditis.

Serum concentrations of interleukin-6, tumour necrosis factor-alpha, and C-reactive protein in patients undergoing major operations

OBJECTIVE

To investigate the kinetics of interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-alpha) and C-reactive protein after a surgical operation.

DESIGN

Prospective study.

SETTING

Teaching hospital, Sweden.

SUBJECTS

28 patients undergoing cardiac operations, joint replacement, or gastric restrictive operations.

INTERVENTIONS

Samples of serum were taken before operation; at 0, 6, and 12 hours; and then daily for six days.

OUTCOME MEASURES

IL-6, TNF-alpha, and C-reactive protein concentrations at specified time points, and their correlation with complications and outcome.

RESULTS

The IL-6 concentration peaked soon after operation, and that of C-reactive protein 48-96 hours later. Serum IL-6 concentrations were highest in the eight patients undergoing cardiac operations. In one patient an infective complication occurred resulting in secondary peaks of IL-6 and C-reactive protein. Three patients who developed postoperative circulatory and respiratory instability had no additional changes in cytokine concentrations. The overall concentrations of IL-6 were raised above 100 pg/ml for a mean of 36 hours after operation and those of C-reactive protein were over 100 mg/l for a mean of 106 hours (p < 0.0001). Serum TNF-alpha concentrations were low in all patients.

CONCLUSION

The maximum serum concentrations of IL-6 and C-reactive protein after surgical operations were comparable to those in patients with sepsis. If IL-6 and C-reactive protein analyses are used in the diagnosis of infective complications, evaluation of the results should be related to the length of time between the operation and sampling, and to the clinical findings. The shorter period during which IL-6 was raised compared with C-reactive protein indicates that IL-6 may be a more useful marker of postoperative infective complications.

Modular Organization of Spinal Nociceptive Reflexes: A New Hypothesis

Recent experimental studies suggest that the nociceptive withdrawal reflex system essentially has a "modular" organization, with each module concerned with the control of a single or a small group of muscles. This organizational principle appears to apply also to some spinoolivocerebellar pathways.

Improving the implementation of cost recovery for health: lessons from Zimbabwe

In the current debate over health financing policy in developing countries, governments are increasingly focusing on cost recovery--having patients pay part or all of their health care costs--as a way to mobilize more resources for health, improve equity by selectively charging the wealthy, and increase efficiency by encouraging reinvestment of fee revenues into cost-effective primary care. Zimbabwe offers an important example of a country with a tradition of levying fees in government health facilities, but where enforcement became lax in the 1980s. In 1991, policymakers resolved to resuscitate and strengthen cost recovery, as part of a broader economic reform program. This paper discusses the strengths and weaknesses of Zimbabwe's cost recovery system, its potential for improvement, and the obstacles to change in revising the fee structure and billing and collection procedures. It argues that cost recovery can help to achieve Zimbabwe's health objectives, but only in conjunction with other measures to redirect public spending to essential public health and clinic care and improve the efficiency of government services. The paper finds that during the 1980s, the fee schedule became badly misaligned with actual medical care costs and created distortions in patient referral patterns. Billing and collection were also weak, because of deficiencies in personnel and information systems and lack of incentives for revenue generation. The paper concludes that if key steps were taken to raise the collections-to-billings ratio, recover fees from privately-insured patients, and adjust fees in line with medical cost inflation, recoveries could increase fourfold, from 5% to 20% of government spending for clinical care. At the same time, access to government health services for the poor could be maintained by improving exemption procedures.