Complexity and interplay of faced adversities and perceived health and well-being in highly vulnerable pregnant women-the Mothers of Rotterdam program.

BACKGROUND: Living in socially disadvantaged circumstances has a widespread impact on one's physical and mental health. That is why individuals living in this situation are often considered vulnerable. When pregnant, not only the woman's health is affected, but also that of her (unborn) child. It is well accepted that vulnerable populations experience worse (perinatal) health, however, little is known about the lived adversities and health of these vulnerable individuals. OBJECTIVES: With this article, insights into this group of highly vulnerable pregnant women are provided by describing the adversities these women face and their experienced well-being. METHODS: Highly vulnerable women were recruited when referred to tailored social care during pregnancy. Being highly vulnerable was defined as facing at least three different adversities divided over two or more life-domains. The heat map method was used to assess the interplay between adversities from the different life domains. Demographics and results from the baseline questionnaires on self-sufficiency and perceived health and well-being were presented. RESULTS: Nine hundred nineteen pregnant women were referred to social care (2016-2020). Overall, women had a median of six adversities, distributed over four life-domains. The heat map revealed a large variety in lived adversities, which originated from two parental clusters, one dominated by financial adversities and the other by a the combination of a broad range of adversities. The perceived health was moderate, and 25-34% experienced moderate to severe levels of depression, anxiety or stress. This did not differ between the two parental clusters. CONCLUSIONS: This study shows that highly vulnerable pregnant women deal with multiple adversities affecting not only their social and economic position but also their health and well-being.

The addition of a boost dose on the primary tumour bed after lumpectomy in breast conserving treatment for breast cancer. A summary of the results of EORTC 22881-10882 "boost versus no boost" trial.

PURPOSE: To investigate the impact of the boost dose to the primary tumour bed in the framework of breast conserving therapy on local control, cosmetic results, fibrosis and overall survival for patients with early stage breast cancer. PATIENTS AND METHODS: Five thousand five hundred and sixty-nine patients after lumpectomy followed by whole breast irradiation of 50 Gy were randomised. After a microscopically complete lumpectomy (5318 patients), the boost doses were either 0 or 16 Gy, while after a microscopically incomplete (251 patients) lumpectomy randomisation was between 10 and 26 Gy. The results at a median follow-up of 10 years are presented. RESULTS: At 10 years, the cumulative incidence of local recurrence was 10.2% versus 6.2% for the 0 Gy and the 16 Gy boost groups (p < 0.0001) and 17.5% versus 10.8% for the 10 and 26 Gy boost groups, respectively (p > 0.1). There was no statistically significant interaction per age group but recurrences tended to occur earlier in younger patients. As younger patients had a higher cumulative risk of local relapse by year 10, the magnitude of the absolute 10-year risk reduction achieved with the boost decreased with increasing age. Development of fibrosis was significantly dependent on the boost dose with a 10-year rate for severe fibrosis of 1.6% after 0 Gy, 3.3% after 10 Gy, 4.4% after 16 Gy and 14.4% after 26 Gy, respectively. CONCLUSION: An increase of the dose with 16 Gy improved local control for patients after a complete lumpectomy only. The development of fibrosis was clearly dose dependent. With 10 years median follow-up, no impact of survival was observed.

Effective palliation by low dose local radiotherapy for recurrent and/or chemotherapy refractory non-follicular lymphoma patients.

In this work, we have studied the response rates and duration of response after low-dose (4 Gy) involved field radiotherapy (LD-IF-RT) in relapsed or chemotherapy refractory indolent and aggressive lymphoma patients. 71 patients (177 symptomatic sites) received LD-IF-RT consisting of 39 males and 32 females with a median age of 69 years (range 43-93). Patients included were those with small lymphocytic lymphoma/chronic lymphocytic leukaemia (n=23), marginal zone lymphoma, nodal type (n=18), mantle cell lymphoma (n=17), and diffuse large B-cell lymphoma (n=13). Bulky disease (5 cm) was present in 73% of all patients. A median of two prior chemotherapy regimens (range 0-10) preceded LD-IF-RT. Median time since diagnosis was 31 months (range 1-216 months). Time to (local) progression was calculated according to the Kaplan-Meier method. Differences in response rates were compared using the chi2-test. The results showed that overall response rate was 87%; complete remission (CR) was reached in 34 patients (48%) and a partial remission (PR) in 28 patients (39%). Stable disease (SD) was maintained in nine patients (13%). The median time to progression (TP) was 12 months and the median time to local progression (TLP) was 22 months. The 34 CR patients showed a median TP of 16 months and a median TLP of 23 months. None of the factors studied (age, sex, lymphoma subtype, radiotherapy regimen, number of prior regimens or time since diagnosis, number of positive sites or largest lymphoma diameter) were found to relate to response. At time of death 70% of patients were without in-field progression after LD-IF-RT. It appears that LD-IF-RT is a valuable asset in the management of relapsed disease in both indolent and aggressive lymphoma and should be considered to palliate symptoms in patients with recurrent and/or chemotherapy refractory disease.

High response rates and lasting remissions after low-dose involved field radiotherapy in indolent lymphomas.

PURPOSE: To study the response rates and duration of response after low-dose (4 Gy) involved field radiotherapy (LD-IF-RT) in patients with recurrent indolent lymphoma. PATIENTS AND METHODS: A total of 109 assessable patients (304 symptomatic sites) were irradiated (53 males and 56 females; median age, 62 years; range, 35 to 93), including 98 patients with follicular lymphoma (43 grade 1 and 55 grade 2), nine extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue-type and two patients with lymphoplasmacytoid lymphoma. Bulky disease (> or =5 cm) was present in 52% of all patients. A median of two prior regimens (range, 0 to 11) preceded LD-IF-RT. The median time since diagnosis was 41 months (range, 2 to 358 months). Time to (local) progression was calculated according to the Kaplan-Meier method. Differences in response rates between treatments within the same patient were compared using the McNemar test. RESULTS: The overall response rate was 92%; complete response was reached in 67 patients (61%), partial response in 34 patients (31%), stable disease in six patients (6%), and progressive disease in two patients (2%). The median time to progression was 14 months. The median time to local progression was 25 months. The 67 patients with complete response showed a median time to progression of 25 months and a median time to local progression of 42 months. None of the factors studied (age, sex, follicular lymphoma grade, radiotherapy regimen, number of previous regimens and previous history, number of positive sites or largest lymphoma diameter) were found to be related to response rate. CONCLUSION: LD-IF-RT is a valuable asset in the management of patients with follicular lymphoma and should be considered in patients with recurrent disease.

The potential impact of treatment variations on the results of radiotherapy of the internal mammary lymph node chain: a quality-assurance report on the dummy run of EORTC Phase III randomized trial 22922/10925 in Stage I--III breast cancer(1).

PURPOSE: To present the results of the dummy run of the European Organization for Research and Treatment of Cancer (EORTC) trial investigating the role of adjuvant internal mammary and medial supraclavicular (IM-MS) irradiation in Stage I--III breast cancer. METHODS AND MATERIALS: All participating institutions were asked to produce a treatment plan without (Arm 1) and with (Arm 2) simultaneous IM-MS irradiation of 1 patient after mastectomy and of 1 patient after lumpectomy. Thirty-two dummy runs have been evaluated for compliance to protocol guidelines, with respect to treatment technique and dose prescription. RESULTS: A number of more or less important deviations in treatment setup and prescription have been found. The dose in the IM-MS region deviated significantly from the prescribed dose in 10% of the cases for Arm 1, and in 21% for Arm 2. Assuming a true 5% 10-year survival benefit from optimal IM-MS irradiation, an increase of only 3.8% will be found due to this suboptimal dose distribution. CONCLUSION: In the dummy run, a number of potential systematic protocol deviations that might lead to false-negative results were detected. By providing recommendations to the participating institutions, we expect to improve the interinstitutional consistency and to promote a high quality irradiation in all institutions participating in the trial.

Transforming growth factor-beta suppresses interferon-gamma-induced toxoplasmastatic activity in murine macrophages by inhibition of tumour necrosis factor-alpha production.

Activation of macrophages plays an important role in the host resistance against intracellular pathogens. Various mechanisms are employed to control the activation processes and limit tissue damage by factors produced by activated macrophages. One of these mechanisms is the production of macrophage-deactivating cytokines, such as tumour growth factor (TGF)-beta. The present study concerns the effects of TGF-beta on interferon (IFN)-gamma-induced activation of murine macrophages with respect to induction of toxoplasmastatic activity, and production of tumour necrosis factor (TNF)-alpha, prostaglandin E2 (PGE2) and reactive nitrogen intermediates (RNI). IFN-gamma activation of macrophages resulted in inhibition of T. gondii proliferation [mean fold increase (FI) = 1.8, control mean FI = 7.0]; polymyxin B had no effect on this activation. The IFN-gamma-induced toxoplasmastatic activity of macrophages was inhibited by TGF-beta (mean FI = 6.3), which was also found for the IFN-gamma-induced production of TNF-alpha, RNI and PGE2 by macrophages. We found that PGE2, which has macrophage deactivating properties, was not involved in the inhibition of macrophage activation by TGF-beta. The deactivating activities of TGF-beta on the IFN-gamma-induced toxoplasmastatic activity and production of RNI are mediated by inhibition of production of TNF-alpha. Addition of exogenous TNF-alpha during the incubation of macrophages with IFN-gamma and TGF-beta abrogated the deactivating activity of TGF-beta. In sum, the results demonstrate that inhibition of TNF-alpha production is a key factor in the TGF-beta-induced suppression of macrophage activation with respect to toxoplasmastatic activity and RNI production.

The influence of the boost in breast-conserving therapy on cosmetic outcome in the EORTC "boost versus no boost" trial. EORTC Radiotherapy and Breast Cancer Cooperative Groups. European Organization for Research and Treatment of Cancer.

PURPOSE: To evaluate the influence of a radiotherapy boost on the cosmetic outcome after 3 years of follow-up in patients treated with breast-conserving therapy (BCT). METHODS AND MATERIALS: In EORTC trial 22881/10882, 5569 Stage I and II breast cancer patients were treated with tumorectomy and axillary dissection, followed by tangential irradiation of the breast to a dose of 50 Gy in 5 weeks, at 2 Gy per fraction. Patients having a microscopically complete tumor excision were randomized between no boost and a boost of 16 Gy. The cosmetic outcome was evaluated by a panel, scoring photographs of 731 patients taken soon after surgery and 3 years later, and by digitizer measurements, measuring the displacement of the nipple of 3000 patients postoperatively and of 1141 patients 3 years later. RESULTS: There was no difference in the cosmetic outcome between the two treatment arms after surgery, before the start of radiotherapy. At 3-year follow-up, both the panel evaluation and the digitizer measurements showed that the boost had a significant adverse effect on the cosmetic result. The panel evaluation at 3 years showed that 86% of patients in the no-boost group had an excellent or good global result, compared to 71% of patients in the boost group (p = 0.0001). The digitizer measurements at 3 years showed a relative breast retraction assessment (pBRA) of 7.6 pBRA in the no-boost group, compared to 8.3 pBRA in the boost group, indicating a worse cosmetic result in the boost group at follow-up (p = 0.04). CONCLUSIONS: These results showed that a boost dose of 16 Gy had a negative, but limited, impact on the cosmetic outcome after 3 years.

Elderly and young driver's reaction to an in-car enforcement and tutoring system.

A system that contrasts driver behaviour with normative behaviour was tested in an advanced driving simulator. Drivers were provided with auditory and visual tutoring messages if deviations were detected from normative, i.e. legally allowed behaviour with respect to a selection of offences. Results showed that the system was very effective in increasing law-abiding behaviour, which has a major positive effect on traffic safety. However, driver mental effort, as indicated by self-reports and drivers' physiological states, was slightly increased in conditions where drivers received feedback. Opinion about the tutoring system was positive in terms of usefulness. Self-reports on satisfaction differed between age groups; young drivers rated it low, while elderly drivers held a positive attitude.

Safety evaluation of a polymerized hemoglobin solution in a murine infection model.

Several investigators have observed that free hemoglobin may increase the mortality rate in experimental Escherichia coli peritonitis in animals. This effect is probably mediated by the heme moiety of hemoglobin, but the mechanism remains controversial. Free hemoglobin might impair neutrophil function, and it might serve as a source of iron, which is necessary for bacterial replication. Several modified hemoglobin solutions, developed as blood substitutes, are currently being tested in clinical studies, but concern exists that these solutions may have the potential to exacerbate a bacterial infection. At the Central Laboratory of the Netherlands Red Cross Blood Transfusion Service, a blood substitute based on modified hemoglobin (PolyHbXl) has been developed that has improved oxygen affinity and prolonged vascular retention. In the present study the potential risk of this solution on the promotion of infections has been evaluated. PolyHbXl was intravenously injected into mice in a clinically relevant dose of 1.5 gm/kg body weight 1 hour before intravenous administration of a sublethal number of Listeria monocytogenes, Salmonella typhimurium, E. coli, or Candida albicans organisms. PolyHbXl did not promote the proliferation of any of these microorganisms in the liver and spleen, nor did it lead to an increased mortality rate in the mice. Also, the in vitro proliferation of L. monocytogenes, S. typhimurium, and E. coli was not increased by PolyHbXl. In conclusion, PolyHbXl does not affect the course of infection with various microorganisms in mice, and no indication was found that this new blood substitute compromises the host defense against infections.

Effect of IFN-gamma and endogenous TNF on the histopathological changes in the liver of Listeria monocytogenes-infected mice.

During primary infection of mice with Listeria monocytogenes, the bacteria proliferate extensively in the liver resulting in the development of inflammatory lesions in this organ. In the present study, the effect of interferon-gamma (IFN-gamma) on the development of these lesions, and the involvement of endogenous tumour necrosis factor-alpha (TNF-alpha) in the IFN-gamma-induced effects were evaluated. During an infection of naive mice with L. monocytogenes, two types of inflammatory lesions in the liver could be distinguished: large necrotic lesions consisting of granulocytes and/or exudate macrophages and small lesions containing mainly mature macrophages, i.e. BM8-expressing cells. Necrotic lesions were characterized by the presence of CD11b-expressing cells and consisted mainly of granulocytes during days 1 and 2 of infection and thereafter of exudate macrophages. The lesions consisting of mature macrophages and lymphocytes were not associated with necrosis and were called granulomatous lesions. Some of the granulomatous lesions contained many cells that expressed Ia antigen, i.e. activated cells. Treatment of mice with recombinant (r)IFN-gamma before injection of L. monocytogenes resulted in a decrease in the number of necrotic lesions and an increase in the number of granulomatous lesions in the liver, which was accompanied by a reduced bacterial proliferation in the liver. The effect of rIFN-gamma on the development of the various types of inflammatory lesions in the liver during infection with L. monocytogenes was abrogated by anti-TNF-alpha antibody and this antibody abrogated the rIFN-gamma-induced reduction of bacterial proliferation in the liver as well. Together, the results demonstrate that endogenous TNF-alpha plays a key role in the effects of rIFN-gamma on the inflammatory response in the liver during an infection with L. monocytogenes.

Murine peritoneal macrophages activated by the mycobacterial 65-kilodalton heat shock protein express enhanced microbicidal activity in vitro.

After an intraperitoneal (i.p.) injection of purified protein derivative, peritoneal macrophages from mice infected with Mycobacterium bovis bacillus Calmette-Guérin (BCG) show an enhanced respiratory burst, inhibit the intracellular proliferation of Toxoplasma gondii, and kill Listeria monocytogenes more efficiently than peritoneal macrophages from normal mice. One of the immunodominant antigens of Mycobacterium spp. is the 65-kDa heat shock protein (Hsp 65), and in the present study, we determined whether injection of this protein into mice leads to activation of their peritoneal macrophages. After an i.p. injection of Hsp 65, peritoneal macrophages from BCG-infected CBA/J mice also released more H2O2, inhibited the proliferation of T. gondii, and killed L. monocytogenes faster than peritoneal macrophages from normal mice, although Hsp 65 was less effective than purified protein derivative. When normal mice were injected with Hsp 65 suspended in saline after a booster injection with Hsp 65, their macrophages did not display enhanced antimicrobial activity, indicating that an adjuvant was required for a cellular immune response against Hsp 65. In the present study, the adjuvant dimethyl dioctadecylammonium bromide (DDA) was preferred because it contains no endotoxin or mycobacterial antigens and because it has been reported that DDA does not induce the production of gamma interferon. Peritoneal macrophages from C57BL/6 and CBA/J mice that had received a subcutaneous injection of Hsp 65 suspended in DDA followed by an i.p. booster injection of Hsp 65 suspended in saline were activated, as indicated by the enhanced production of H2O2, inhibition of the intracellular proliferation of T. gondii, and increased rate of intracellular killing of L. monocytogenes in vitro relative to that by resident peritoneal macrophages and peritoneal macrophages obtained from mice that had received ovalbumin instead of Hsp 65. The rate of phagocytosis of L. monocytogenes was not affected by Hsp 65 treatment. Despite the in vitro expression of enhanced microbicidal activity of peritoneal macrophages, no difference in the growth of L. monocytogenes in the liver and spleen between Hsp 65-treated and control mice was found.

Endogenous tumor necrosis factor alpha is required for enhanced antimicrobial activity against Toxoplasma gondii and Listeria monocytogenes in recombinant gamma interferon-treated mice.

In vitro studies have shown that macrophages stimulated with recombinant gamma interferon (rIFN-gamma) produce tumor necrosis factor alpha (TNF-alpha), which in an autocrine fashion activates these cells. The aim of the present study was to determine whether endogenously formed TNF-alpha also is required for rIFN-gamma-induced macrophage activation and enhanced antimicrobial activity in vivo. After an intraperitoneal injection of rIFN-gamma into CBA/J mice, their peritoneal macrophages released enhanced amounts of NO2- and inhibited the intracellular proliferation of Toxoplasma gondii. Injection of neutralizing antibodies against TNF-alpha simultaneously with the rIFN-gamma completely inhibited both the release of NO2- by macrophages and their toxoplasmastatic activity. Similar results were observed after intraperitoneal injection of a competitive inhibitor of L-arginine, NG-monomethyl-L-arginine, together with rIFN-gamma, demonstrating that in vivo L-arginine-derived reactive nitrogen intermediates are essential for the induction of toxoplasmastatic activity. Intravenous injection of rIFN-gamma inhibited the growth of Listeria monocytogenes in the livers and spleens of mice; this effect was abrogated by antibodies against TNF-alpha. Intravenous injection of a large dose of rTNF-alpha resulted in a decrease in the number of bacteria in the liver and spleen, but an injection of rIFN-gamma and rTNF-alpha did not result in enhanced inhibition of the proliferation of L. monocytogenes. Together, the results of the present study are the first to demonstrate that endogenous TNF-alpha is required in vivo for the expression of macrophage activation with respect to the release of reactive nitrogen intermediates and toxoplasmastatic activity and for enhanced listericidal activity in the livers and spleens of mice stimulated with rIFN-gamma.

Intravenous injection of interferon-gamma inhibits the proliferation of Listeria monocytogenes in the liver but not in the spleen and peritoneal cavity.

In the present study the effects of intravenous administration of recombinant interferon-gamma (IFN-gamma) on both the proliferation of Listeria monocytogenes in the liver and spleen of mice and the listericidal activity of their peritoneal macrophages were investigated. A single intravenous injection of 1 x 10(6) U or three injections of 2 x 10(5) U recombinant IFN-gamma (rIFN-gamma) induced optimal activation of resident and exudate peritoneal macrophages, as judged by their ability to inhibit the intracellular proliferation of Toxoplasma gondii and their enhanced release of H2O2 and NO2-. The rate of intracellular killing of L. monocytogenes by the rIFN-gamma-activated resident and exudate macrophages was not higher than that by resident macrophages. Addition of 10 ng lipopolysaccharides (LPS) to the rIFN-gamma also did not enhance the bactericidal activity of the activated peritoneal macrophages. The decrease in the number of L. monocytogenes in the peritoneal cavity of mice that had received an i.p. injection of 1 x 10(4) U rIFN-gamma was similar to that in control mice. Intravenous administration of 1 x 10(5) rIFN-gamma activated cells in the liver, as indicated by the increased expression of Ia antigen, and reduced the rate of proliferation of L. monocytogenes in the liver relative to that in control mice when 0.1 LD50 or 1 LD50 L. monocytogenes were injected. However, when 10 LD50 L. monocytogenes were administered there was no effect on their proliferation. The number of L. monocytogenes found initially in the spleen of rIFN-gamma-treated mice was 20-30% of that in the spleen of control mice, but the rate of proliferation of L. monocytogenes was not reduced. These divergent results for the proliferation of L. monocytogenes in the liver, spleen and peritoneal cavity indicate that cells other than macrophages and/or as yet unknown local factors play an important role in the listericidal activity.

Hydrocortisone treatment of BCG-infected mice impairs the activation and enhancement of antimicrobial activity of peritoneal macrophages.

The present study concerns the effect of hydrocortisone (HC) on the effector functions of Bacillus Calmette Guerin-purified protein derivative (BCG-PPD)-activated macrophages. Such activated macrophages release greater amounts of H2O2 and NO2-, inhibit the intracellular proliferation of T. gondii and kill L. monocytogenes more efficiently than resident macrophages. This activation was not fully expressed by macrophages from BCG-activated mice that had received a subcutaneous injection of HC 2 days before intraperitoneal injection of PPD, since the inhibition of the intracellular proliferation of T. gondii, the release of NO2- and the rate of intracellular killing of L. monocytogenes were lower than in macrophages from BCG-PPD-activated mice. However, treatment with HC did not impair the release of H2O2 by BCG-PPD-activated macrophages. The results show that the treatment of infected mice with HC inhibits their ability to develop adequate intracellular microbicidal mechanisms.

IFN-gamma-induced L-arginine-dependent toxoplasmastatic activity in murine peritoneal macrophages is mediated by endogenous tumor necrosis factor-alpha.

Activated murine peritoneal macrophages inhibit the intracellular proliferation of Toxoplasma gondii and produce a number of cytokines, such as TNF-alpha and IL-1. Both TNF-alpha and IL-1 have been reported to be involved in the immune response against various microorganisms, but the mechanisms responsible for these effects are not known. In the present study it was investigated whether endogenously produced TNF-alpha and IL-1 are involved in the activation of peritoneal macrophages by rIFN-gamma leading to toxoplasmastatic activity and the production of reactive nitrogen intermediates. The rIFN-gamma-induced toxoplasmastatic activity was inhibited by neutralizing antibodies against mouse TNF-alpha in a dose-dependent and time-dependent way, but neutralizing antibodies against mouse IL-1 alpha and IL-1 beta did not affect this activity. Involvement of TNF-alpha in the induction of toxoplasmastatic activity was confirmed by our finding that rTNF-alpha in combination with a nonactivating concentration of rIFN-gamma inhibited the intracellular proliferation of T. gondii. No synergistic activity of rIL-1 and rIFN-gamma on the inhibition of T. gondii proliferation was found. Both rTNF-alpha and rIL-1 alpha alone inhibited the intracellular proliferation of T. gondii only slightly. Because it has been reported recently that activated macrophages produce reactive nitrogen intermediates that are essential in the induction of toxoplasmastatic activity, we investigated whether these intermediates are involved in the TNF-dependent induction of toxoplasmastatic activity. Neutralizing antibodies against mouse TNF-alpha inhibited also the release of NO2- by rIFN-gamma-activated macrophages almost completely. Macrophages incubated with rTNF-alpha in combination with a nonactivating concentration of rIFN-gamma released substantial amounts of NO2-, but rTNF-alpha and rIL-1 alpha alone, and the combination of rIL-1 alpha and a nonactivating concentration of rIFN-gamma induced only little NO2(-)-release by macrophages. To assess whether reactive nitrogen intermediates act directly or indirectly on the intracellular proliferation of T. gondii, macrophages were incubated with the L-arginine analog NG-monomethyl-L-arginine or the NADPH-inhibitor diphenylene iodonium, both inhibitors of the generation of reactive nitrogen intermediates. Good correlation was found between toxoplasmastatic activity and the release of NO2- during the 24-h activation period before infection of the macrophages with T. gondii, but no correlation was found between toxoplasmastatic activity and the release of NO2- during infection of the macrophages.(ABSTRACT TRUNCATED AT 400 WORDS)

Nitrite production by activated murine macrophages correlates with their toxoplasmastatic activity, Ia antigen expression, and production of H2O2.

Activated macrophages have various characteristics in common with exudate and resident macrophages, but the ability to inhibit intracellular proliferation of the protozoa Toxoplasma gondii, the expression of Ia antigen and the capacity to produce H2O2 varies among these cells. Assessment of these features of macrophages, which are generally used as criteria for macrophage activation, has certain drawbacks. Since activated murine macrophages, but not exudate or resident macrophages, produce considerable amounts of NO2-, assessment of NO2- production by these cells might serve as a measure of macrophage activation. The aim of the present study was to find out whether NO2- production by murine peritoneal macrophages correlates with the three generally accepted criteria for macrophage activation. Quantitative data on resident, exudate and activated macrophages revealed that the production of NO2- stimulated by a calcium-ionophore correlates best with the ability to inhibit the proliferation of T. gondii, Ia antigen expression, and capacity to produce H2O2. Because it is rapid and easy to perform, measurement of the amount of NO2- produced by murine macrophages stimulated with a calcium-ionophore offers the most practical criterion for distinction between activated macrophages and exudate and resident macrophages.

Microbicidal activities of Salmonella typhimurium- and interferon-gamma-activated mouse peritoneal macrophages.

Activation of mouse peritoneal macrophages during infection of mice by various facultative intracellular bacteria and after intravenous injection of recombinant interferon-gamma (rIFN-gamma) was studied. Macrophage activation was demonstrated on the basis of three different criteria, i.e. inhibition of Toxoplasma gondii proliferation, enhanced release of H2O2 and increased expression of Ia antigen. Macrophages activated during an infection with Salmonella typhimurium showed no enhanced salmonellacidal or listericidal activity relative to control macrophages, whereas Listeria-activated macrophages killed Listeria but not Salmonella faster than control macrophages. The rate of proliferation of Salmonella in spleen and liver of activated mice was comparable to the proliferation in the organs of control mice. rIFN-gamma-activated macrophages displayed neither an enhanced salmonellacidal nor an enhanced listericidal activity. When high numbers of Listeria were injected intravenously the proliferation in spleen and liver of rIFN-gamma-treated and control mice was similar. The proliferation of Listeria in the liver of rIFN-gamma-treated mice was less than in control mice when 1 LD50 or lower numbers of bacteria were injected. It is concluded that peritoneal macrophages become activated during infections of mice with various intracellular pathogens. However, these activated macrophages do not show enhanced bactericidal activity against all bacteria. Furthermore, rIFN-gamma is not sufficient to enhance the listericidal activity of macrophages.

Activation of mouse peritoneal macrophages during infection with Salmonella typhimurium does not result in enhanced intracellular killing.

Our study was performed to investigate whether macrophages become activated during an infection with Salmonella typhimurium and, if so, whether these activated macrophages kill S. typhimurium faster than resident macrophages. Mice received i.v. injections with a sublethal number of S. typhimurium; on about day 12 of the infection the numbers of bacteria in the liver and the spleen were maximal. During the infection, activation of peritoneal macrophages could be demonstrated on the basis of three criteria, i.e., the ability to inhibit the proliferation of Toxoplasma gondii, an enhanced production of H2O2 and an increased expression of Ia Ag. The rate of in vitro intracellular killing of S. typhimurium by these activated macrophages was not increased compared to that for resident macrophages. To determine the growth of S. typhimurium in activated mice a nalidixic acid-resistant mutant strain, called S. typhimurium 510R, was used. The net growth rates of the mutant S. typhimurium 510R in the spleen of S. typhimurium 510-activated and normal mice were similar. However, in the liver of S. typhimurium 510-activated mice the number of S. typhimurium 510R did not change during 3 to 48 h after injection. The role of specific antibodies during the initial phase of the infection was negligible, because only low levels of antibodies were detected during the first 15 days of infection and the growth rates of S. typhimurium 510 in the spleen and liver of mice with high titers of antibodies were not significantly different from the rates in normal mice. The results of this study demonstrate that although macrophages become activated during an infection with S. typhimurium, these cells do not display an enhanced bactericidal activity in vitro and in vivo no significant effect on the growth rate of S. typhimurium in the spleen and a bacteriostatic effect in the liver is found. Hence macrophage activation is probably not very important in the host defense against S. typhimurium.

Salmonella decontamination of broiler carcasses with lactic acid, L-cysteine, and hydrogen peroxide.

Experiments on salmonella decontamination of broiler carcasses with lactic acid, L-cysteine, and hydrogen peroxide were performed. Treatment with lactic acid (1%) and hydrogen peroxide (.5%) resulted in a 4-log cycle reduction in colony forming units of Salmonella typhimurium both with pure cultures and with artificially inoculated broiler carcasses. L-cysteine was nonbactericidal in these experiments.

[A comparison of 3 isolation methods for the demonstration of Salmonella bacteria in fryer-chicken feed]. / Een vergelijking van drie isolatie-methoden voor het aantonen van Salmonella-bacteriën in braadkuikenvoeders.

167 Samples of fryer chicken feed were examined for the presence of Salmonella using three different methods of isolation. These methods consisted in the isolation of Salmonella using procedure ISO-3565, this method but supplemented by treatment with hydrogen sulphide (ISO + H2S) and the membrane filter disc immuno-immobilisation method (MFDI). In addition, thirty-three samples were examined by the ISO and ISO + H2S techniques. 200 Grams of feed of each sample were studied. A total number of fifteen samples (7.5 per cent) were found to be positive for Salmonella, thirteen of which were examined by the ISO-3565 method of isolation of Salmonella. When the other methods were employed, only five samples were found to be positive for Salmonella using the ISO + H2S technique and two using the MFDI method. When all three methods were used, they failed to produce positive results in each sample which had been found to be positive for Salmonella. The differences in the number of positive samples were found to be significantly (P less than 0.01) in favour of the ISO method. When a choice has to be made between the method used in the detection of Salmonella, the ISO-3565 method of isolating Salmonella is to be preferred.