[Saw Injuries to the Hand - Epidemiological Aspects]. / Sägeverletzungen der Hand ­ epidemiologische Aspekte.

Background: No current studies regarding saw injuries have been published in German literature for quite some time. Despite awareness measures and safety instructions, saw accidents along with crush injuries are the most common causes of severe hand injuries. Approximately 12,000 circular saw injuries occur in Germany each year. Since professional providers have increased prices due to the rising energy costs and a wide range of different home appliance saws are available, increasing use has been made of portable circular saws in the do-it-yourself market sector. Patients and methods: At our hospital, we evaluated the data of 51 male patients with saw injuries. The present study investigated factors that may contribute to accidents involving saws. Results: 80 % of the accidents occurred at home, usually on weekends or after work. 51 % of the accidents happened while patients cut firewood. In 84 % of the cases, an electric table saw was used. The majority of severe hand injuries were sustained with lower priced saws. Injuries occurred most frequently between 11 a. m. and 2 p. m., primarily with injuries to bones, tendons, blood vessels and nerves. Replantable amputations or partial amputations occured rarely. In 37 % of the patients, anatomical reconstruction using osteosynthesis and/or microsurgical techniques was performed successfully. Conclusions: Saw injuries to the hand are sustained almost exclusively by men. Serious injuries from low-priced table saws and due to the lack of protective covering are predominant. Preventive measures and mandatory training could reduce the number of saw injuries in the years to come. The results obtained by us largely confirm the data from previous publications.

[Talus Fractures - an Update]. / Talusfrakturen ­ ein Update.

Background: Talus fractures are rare and often result from axial trauma. As most of the talus surface is covered by cartilage, the blood supply is limited. Thus talus fractures are seen as one of the most severe fractures and often lead to significant long-term complications. Several studies suggest that the initial fracture classification can lead to correct treatment and that this can influence the long-term outcome. The aim of the current study was to investigate the importance of the initial fracture classification in respect to the radiological outcome in a large patient cohort. Patients and Methods: Over a span of 12 years, 61 patients with talus fractures were treated at our institution. Overall 45 patients were available for a retrospective analysis. Correlation analysis was performed between the initial fracture severity and the radiological outcome. Results: The average follow-up was 17.3 months (range 6-68). Significant correlations were found between the Marti-Weber Classification and Bargon Score (rs = 0.78; p < 0.0001), as well as between the Hawkins Classification and the Bargon Score (rs = 0.80; p < 0.0001). Conclusions: Precise prediction of the expected radiological outcome of talar neck and body fractures is possible through the initial fracture classification alone. Computed tomography is the accepted standard to determine the exact diagnosis and extent of injury.

RpiRc Is a Pleiotropic Effector of Virulence Determinant Synthesis and Attenuates Pathogenicity in Staphylococcus aureus.

In Staphylococcus aureus, metabolism is intimately linked with virulence determinant biosynthesis, and several metabolite-responsive regulators have been reported to mediate this linkage. S. aureus possesses at least three members of the RpiR family of transcriptional regulators. Of the three RpiR homologs, RpiRc is a potential regulator of the pentose phosphate pathway, which also regulates RNAIII levels. RNAIII is the regulatory RNA of the agr quorum-sensing system that controls virulence determinant synthesis. The effect of RpiRc on RNAIII likely involves other regulators, as the regulators that bind the RNAIII promoter have been intensely studied. To determine which regulators might bridge the gap between RpiRc and RNAIII, sarA, sigB, mgrA, and acnA mutations were introduced into an rpiRc mutant background, and the effects on RNAIII were determined. Additionally, phenotypic and genotypic differences were examined in the single and double mutant strains, and the virulence of select strains was examined using two different murine infection models. The data suggest that RpiRc affects RNAIII transcription and the synthesis of virulence determinants in concert with σ(B), SarA, and the bacterial metabolic status to negatively affect virulence.

The role of IL-1ß in Pseudomonas aeruginosa in lung infection.

This mini-review examines the role of the pro-inflammatory cytokine interleukin (IL)-1ß in the interaction of Pseudomonas aeruginosa and the host immune system during lung infection. Different studies show that the reduction of the inflammatory response, especially a decrease in IL-1ß, leads to a better outcome in acute lung infection with this bacterium. This includes a higher survival rate, reduced damage to the lung tissue and, in particular, a better clearance of the airways and the tissue of the lungs from P. aeruginosa.

Effects of macrophage-activating lipopeptide-2 (MALP-2) on the vascularisation of implanted polyurethane scaffolds seeded with microvascular fragments.

The seeding of scaffolds with adipose tissue-derived microvascular fragments represents a promising strategy to establish a sufficient blood supply in tissue constructs. Herein, we analysed whether a single application of macrophage-activating lipopeptide-2 (MALP-2) at the implantation site further improves the early vascularisation of such microvessel-seeded constructs. Microvascular fragments were isolated from epididymal fat pads of C57BL/6 mice. The fragments were seeded on polyurethane scaffolds, which were implanted into mouse dorsal skinfold chambers exposed to MALP-2 or vehicle (control). The inflammatory host tissue response and the vascularisation of the scaffolds were analysed using intravital fluorescence microscopy, histology and immunohistochemistry. We found that the numbers of microvascular adherent leukocytes were significantly increased in MALP-2-treated chambers during the first 3 days after scaffold implantation when compared to controls. This temporary inflammation resulted in an improved vascularisation of the host tissue surrounding the implants, as indicated by a higher density of CD31-positive microvessels at day 14. However, the MALP-2-exposed scaffolds themselves presented with a lower functional microvessel density in their centre. In addition, in vitro analyses revealed that MALP-2 promotes apoptotic cell death of endothelial and perivascular cells in isolated microvascular fragments. Hence, despite the beneficial pro-angiogenic properties of MALP-2 at the implantation site, the herein evaluated approach may not be recommended to improve the vascularisation capacity of microvascular fragments in tissue engineering applications.

Expression of caveolin-1 and podocalyxin in rat lungs challenged with 2-kDa macrophage-activating lipopeptide and Flt3L.

Caveolin-1 is one of the important regulators of vascular permeability in inflamed lungs. Podocalyxin is a CD34 protein expressed on vascular endothelium and has a role in podocyte development in the kidney. Few data are available on the expression of caveolin-1 and podocalyxin in lungs challenged with Toll-like receptor 2 (TLR2) agonists such as mycoplasma-derived macrophage activating lipopeptide or with immune modulators such as Fms-like tyrosine kinase receptor-3 ligand (Flt3L), which expands dendritic cell populations in the lung. Because of the significance of pathogen-derived molecules that act through TLR2 and of the role of immune modulators in lung physiology, we examine the immunohistochemical expression of caveolin-1 and podocalyxin in lungs from rats challenged with a 2-kDa macrophage-activating lipopeptide (MALP-2) and Flt3L. Normal rat lungs expressed caveolin-1 in alveolar septa, vascular endothelium and airway epithelium, especially along the lateral borders of epithelial cells but not in alveolar macrophages. MALP-2 and Flt3L decreased and increased, respectively, the expression of caveolin-1. Caveolin-1 expression seemed to increase in microvessels in bronchiole-associated lymphoid tissue (BALT) in Flt3L-challenged lungs but not in normal or MALP-2-treated lungs. Podocalyxin was absent in the epithelium and alveolar macrophages but was present in the vasculature of control, Flt3L- and MALP-2-treated rats. Compared with control and MALP-2-treated rats, Flt3L-treated lungs showed greater expression of podocalyxin in BALT vasculature and at the interface of monocytes and the endothelium. These immunohistochemical data describing the altered expression of caveolin-1 and podocalyxin in lungs treated with MALP-2 or Flt3L encourage further mechanistic studies on the role of podocalyxin and caveolin-1 in lung inflammation.

Toll-like receptor 2/6-dependent stimulation of mesenchymal stem cells promotes angiogenesis by paracrine factors.

Reconstruction of critical size bone defects represents a major challenge in orthopaedic surgery. Insufficient angiogenesis is a limiting factor for engraftment of large-scale tissue transplants. Transplantation or stimulation of local mesenchymal stem cells (MSCs) represents a potential solution to enhance angiogenesis. We recently identified angiogenic properties for the Toll-like receptor (TLR) 2/6 agonist MALP-2 and now investigated if MALP-2 could be used to stimulate MSCs in order to promote angiogenesis in vitro and in vivo. Human MSCs from the bone marrow of healthy subjects were isolated, cultured and expanded in vitro and were shown to be positive for mesenchymal stem cells markers as well as for the MALP-2 receptors TLR2 and TLR6. MALP-2 directly enhanced migration but not proliferation of human MSCs. Conditioned medium from MALP-2 stimulated MSCs significantly increased proliferation, migration and tube formation of endothelial cells. Analysis of the conditioned medium from MSCs revealed that MALP-2 stimulation enhanced the secretion of several chemokines and growth factors including vascular endothelial growth factors (VEGF) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Finally, we studied MALP-2 effects on MSCs in a sheep model of tissue engineering in vivo. Therefore, MSCs were isolated from the iliac crest of black head sheep and co-cultivated with MALP-2 ex vivo. Implantation of autologous MSCs within a scaffold cylinder into the M. latissimus dorsi significantly enhanced vessel density of these constructs after 6 months. We here present the first evidence that TLR2/6-dependent stimulation of MSCs promotes angiogenesis in vitro and in vivo offering a novel strategy for therapeutic angiogenesis, e.g., for tissue engineering of bone.

[The effects of tobacco smoke on alveolar macrophages - an in vivo mouse lung model for short-term smoking]. / Die Auswirkungen von Tabakrauch auf Alveolarmakrophagen - ein In-vivo-Kurzzeitrauchmodell zur Mauslunge.

BACKGROUND: The effect of cigarette smoke (CS) on the phagocytosis of alveolar macrophages is discussed controversially on the basis of in vitro experiments. In this short report we describe the in vivo observations that we have performed. METHODS: For this purpose mice were exposed to CS for three consecutive days. One day later the fluorescent microspheres were administered intratracheally and the lung surface was investigated using long-distance fluorescence microscopy. RESULTS: We found that the numbers of neutrophils which engulfed particles was increased in the CS group as compared to controls. The overall phagocytic activity was not significantly different after CS exposure. CONCLUSIONS: In conclusion the phagocytosis of alveolar macrophages and neutrophils after short time CS exposure was not affected. Further investigations will need to look for the effects of long-term CS exposure and the phagocytosis of living bacteria.

All-trans retinoic acid results in irregular repair of septa and fails to inhibit proinflammatory macrophages.

All-trans retinoic acid (ATRA) is controversially discussed in emphysema therapy. We re-evaluated ATRA in the elastase model and hypothesised that beneficial effects should be reflected by increased alveolar surface area, elastin expression and downregulation of inflammatory mediators and matrix metalloproteinases (MMPs). Emphysema was induced by porcine pancreatic elastase versus saline in Sprague-Dawley rats. On days 26-37, rats received daily intraperitoneal injections with ATRA (500 µg · kg(-1) body weight) versus olive oil. Lungs were removed at day 38. Rat alveolar epithelial L2 cells were incubated with/without elastase followed by ATRA- or vehicle-treatment, respectively. ATRA only partially ameliorated structural defects. Alveolar walls exhibited irregular architecture: increased arithmetic mean thickness, reduction in surface coverage by alveolar epithelial cells type II. ATRA only partially restored reduced soluble elastin. It tended to increase the ratio of ED1(+):ED2(+) macrophages. Bronchoalveolar lavage (BAL) cells exhibited a proinflammatory state and high expression of interleukin-1ß, cytokine-induced neutrophil chemoattractant-1, tumour necrosis factor-α, nuclear factor-κB, MMP-2, MMP-9, MMP-12, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in emphysema, with ATRA exerting only few effects. MMP-7 was highly induced by ATRA in healthy but not in emphysematous lungs. ATRA reduced both MMP-2 and TIMP-1 activity in BAL fluid of emphysematous lungs. ATRA-therapy may bear the risk of unwanted side-effects on alveolar septal architecture in emphysematous lungs.

Ceremonies of gratitude following the dissection course: A report on procedures in departments of anatomy in German speaking countries.

The departments of anatomy in Germany, Austria and the German-speaking part of Switzerland were sent comprehensive (18 items) questionnaires requesting details on memorial ceremonies held at the close of the dissection course in the medical curriculum, including objectives, organization, number of participants and the role of the medical students. The response rate was very high (95%). In more than 95% of instances a ceremony is held, initiated mainly after 1970. The titles of the ceremony range from commemoration ceremony (42%), service of mourning (19%) memorial service (19%) to ceremony of gratitude (7%). The number of participants exceeds 300 in 15% of these ceremonies. The invitation comes mostly from the student group organizing the ceremony (62%). The ceremony is offered mainly for the students of the course (23%), for student tutors (16%), relatives of the body donors (23%) and scientific staff (15%). The students actively participate with musical contributions (19%), gestures such as candles (17%) and flowers (12%), speeches (17%) and readings (12%). The relevance of the practical dissection course and body donation programs is also discussed. The results are compared to ceremonies in various countries with different religious backgrounds. This dissection course is unique among all courses in the medical curriculum as it obviously also has spiritual aspects.

Mitochondrial regulation of reactive oxygen species (ROS) production-Unexpected observations in early postnatal cerebral vasculature.

Nicotinamide-nucleotide-transhydrogenase (Nnt) is a mitochondrial protein. It is altered and functionally lacking in the C57BL/6J sub-strain. This leads to the generation of more radical oxygen species than in the C57BL/6N sub-strain. During studies on the effect of Nnt in perinatal hypoxia the cerebral vasculature was investigated in postnatal day 9 mice using post mortem arterial filling with silicone rubber compounds. Surprisingly, the tiny vessels were no longer uniformly filled and a bleb-like pattern occurred in both sub-strains. Furthermore, considerably more bleb-like spots were observed in the C57Bl/6J sub-strain than in the C57Bl/6N sub-strain. These blebs might be the result of feathery vessels bursting. It remains unclear how the mechanisms in the used strains differ. Nnt might influence the vascular structure or its development and mechanisms and should be investigated further.

Brain damage resulting from postnatal hypoxic-ischemic brain injury is reduced in C57BL/6J mice as compared to C57BL/6N mice.

Perinatal hypoxia is a critical complication during delivery and is mostly studied in animal models of postnatal hypoxic-ischemic brain injury. We here studied the effects of postnatal hypoxic-ischemic brain injury in two different sub-strains of C57BL/6 mice, i.e. C57BL/6J and C57BL/6N mice. These two sub-strains show different metabolic properties, for instance an impaired glucose tolerance in C57BL/6J mice. Genetically, this was linked to differences in their nicotinamide nucleotide transhydrogenase (Nnt) genes: In C57BL/6J mice, exons 7-11 of the Nnt gene are deleted, resulting in the absence of functional Nnt protein. The mitochondrial Nnt-protein is one of several enzymes that catalyses the generation of NADPH, which in turn is important for the elimination of reactive oxygen species (ROS). As ROS is thought to contribute to the pathophysiology of hypoxia-ischemia, the lack of Nnt might indirectly increase ROS levels and therefore result in increased brain damage. We therefore hypothesize that lesion score and lesion size will increase in C57BL/6J mice as compared to C57BL/6N mice. Surprisingly, the results showed exactly the opposite: C57BL/6J mice showed a decrease in lesion score and size, associated with a reduced number of apoptotic cells and activated microglia. In contrast, the number of cells with ROS-induced DNA modifications (detected by 8OHdG) was higher in C57BL/6J than C57BL/6N mice. In conclusion, C57BL/6J mice showed reduced ischemic consequences after postnatal hypoxic-ischemic brain injury compared to C57BL/6N mice, with the exception of the amount of ROS-induced DNA-damage. These differences might relate to the lack of Nnt, but also to a modified metabolic setting (cardiovascular parameters, oxygen and glucose metabolism, immune function) in C57BL/6J mice.

Mini-laparotomy and full laparotomy, but not laparoscopy, alter hepatic macrophage populations in a rat model.

BACKGROUND: Immune function is better preserved by laparoscopic versus conventional surgery. Numerous mediators of the systemic trauma response are synthesized and/or regulated by the liver. However, it has been stated that the advantages of laparoscopic surgery are no more obvious when conventional operations are performed via mini-laparotomy. We set out to compare the impact of laparoscopy and mini- and full laparotomy on the hepatic macrophage populations. METHODS: Male Lewis rats were subjected to anesthesia alone (control), mini-laparotomy (1 cm), full laparotomy (7 cm), or laparoscopy for 60 min. Endpoints were the total protein in the peritoneal lavage fluid, hepatic ED-1 cells (recruited monocytes), hepatic ED-2 cells (Kupffer cells), the expression of OX-6 in the liver, and C-reactive protein (CRP) in plasma. RESULTS: Protein in the peritoneal lavage fluid increased significantly after all interventions. Full laparotomy was accompanied by an enhancement in ED-1-positive monocytes in the liver parenchyma compared to all other groups (p < 0.001). Mini- and full laparotomy led to an increase in ED-2-positive Kupffer cells (p < 0.001). Laparoscopy did not affect the number of monocytes/macrophages. There was no significant alteration of OX-6 expression in either group. No change in the cellular composition in the periportal fields was observed. The CRP plasma levels did not significantly differ between groups. CONCLUSIONS: Laparoscopy completely prevents hepatic macrophage populations from expansion and normal cell disposition is preserved. Laparotomy, irrespective of incision size, increases the number of Kupffer cells. Moreover, full laparotomy, but not mini-laparotomy or laparoscopy, causes an increase in hepatic monocyte recruitment. The regulating pathways after surgery differ from other immunologic challenges, such as sepsis, in which immunocompetent cells accumulate and are stimulated in the periportal fields.

Effects of macrophage-CSF on pulmonary-macrophage repopulation after bone marrow transplantation.

Pulmonary infections are important causes of morbidity and mortality in immunosuppressed patients after transplantation. After experimental irradiation and syngeneic bone marrow transplantation in mice, macrophages show reduced repopulation in the lung compared with that in other tissues. Macrophages are major microbicidal immune effector cells in host pulmonary defense. Therefore, we examined the role of locally applied cytokines for macrophage repopulation in the lung. An accelerated repopulation of macrophages in the lung was observed after intranasal application of macrophage-colony stimulating factor (M-CSF), but this effect was not enhanced by a combination of M-CSF with interleukin (IL)-3. Local proliferation contributed to this effect. Macrophages in the lung tissue of M-CSF-treated mice displayed greater secretion of IL-6, whereas M-CSF treatment did not enhance the gene expression of other macrophage-specific chemokines. The role of M-CSF treatment was determined in pulmonary murine cytomegalovirus infection using an irradiation/reconstitution model. The M-CSF treatment had no effect on virus load in the lung tissue. However, phosphate-buffered saline-treated mice seemed to develop stronger inflammation after viral infection than M-CSF-treated mice. We conclude that local M-CSF treatment modulates cellular inflammation in the lung during immunosuppression.

Stereological quantification of carboxyfluorescein-labeled rat lung metastasis: a new method for the assessment of natural killer cell activity and tumor adhesion in vivo and in situ.

The function of natural killer (NK) cells is often studied by assessing in vitro levels of NK cell mediated lysis of target cells, or by assessing in vivo levels of lung tumor cell retention or metastatic colonization of intravenously injected tumor cells. However, these methods do not permit direct quantification and visualization of NK cells and their targets in vivo and in situ. Here, a new approach is described to visualize effector-to-target interactions as well as to estimate total numbers of targets in the lung, in vivo and in situ. MADB106 tumor cells were vitally labeled using carboxyfluorescein (CFSE) and intravenously (i.v.) injected into Fischer 344 rats (10(6) cells/rat). This mammary adenocarcinoma derived cell line is syngeneic to the inbred Fischer 344 rat and highly sensitive to NK cell activity in vivo. Effector-to-target interactions were visualized by immunostaining. Using the optical fractionator method, total numbers of CFSE-labeled MADB106 tumor cells were estimated in the left lung of the animals 5 min after tumor inoculation. To further demonstrate the usefulness of this approach in reflecting in vivo processes, rats were inoculated with MADB106 cells and simultaneously with a single i.v. bolus of either 1 microg/kg adrenaline or saline. Both lungs were removed 5 min later. Adrenaline caused a significant 80% reduction in the total number of lung CFSE-labeled MADB106 tumor cells, suggesting a rapid modulation of metastasis by stress hormones. This new approach facilitates the monitoring of effector-to-target interactions and the quantification of immune cell function or tumor adhesion in vivo and in situ.

Evidence of recurrent atypical meningioma with rhabdoid transformation and expression of pyrogenic cytokines in a child presenting with a marked acute-phase response: case report and review of the literature.

Children presenting with acute systemic illnesses that lack specific clinical or serological defining features may be diagnosed as having a chronic infection, an atypical systemic vasculitis or a connective tissue disease, but often turn out to have occult neoplasias. Cytokines have been implicated in causing many of the systemic effects in such cases. In this study, we describe the case of a 9-year-old boy presenting at an interval of 18 months with a marked acute-phase response due to a recurrent atypical meningioma with rhabdoid transformation of the tentorium cerebelli. Resection of the recurrent tumor was curative. We evaluated in detail the local and systemic production of cytokines released by the primary and the recurrent tumor. Blood and CSF samples were taken pre-, intra-, and postoperatively, and the production of IL-6, IL-1beta, and TNF-alpha was measured by enzyme-linked immunosorbent assays (ELISA). The level of IL-6 in CSF was about 150-fold increased before tumor resection, normalizing postoperatively. On the contrary, the levels of IL-1beta and TNF-alpha in CSF and of IL-6, IL-1beta, and TNF-alpha in serum were pre-, intra-, and postoperatively within normal limits. Cytokine production was also evaluated immunohistochemically, and confirmed strong IL-6 and TNF-alpha expression in the primary and the recurrent tumor, while expression of IL-1beta was lacking. The scattered MHC class II- and leukocyte common antigen (LCA)-expressing inflammatory cells, which were infiltrating exclusively the tumoral stroma, had no detectable cytokine immunoreactivity. We conclude that chronic IL-6 and TNF-alpha production by the tumor cells in this patient was responsible for the severe systemic illness with which he presented.

Transplantation of H-2Kb-transgenic adrenocortical cells in the mouse having undergone an adrenalectomy: functional and morphological aspects.

BACKGROUND: A new model of cellular adrenocortical transplantation after bilateral adrenalectomy in the mouse was established. This model was used to study the effects of the expression of the transgenic MHC class I molecule H-2K(b) (Kb) on graft survival and morphologic features, corticosterone secretion, and the possibility of tolerance induction in the recipient. METHOD: A single cell suspension of purified adrenocortical cells was grafted under the kidney capsule of B10.Br (H-2k) mice having adrenalectomies. Syngeneic, fully MHC-mismatched, and MHC class I-incompatible Kb-transgenic mice served as donor strains. To analyze graft function, urinary excretion and serum levels of corticosterone were monitored over 100 days. Tolerance induction in the graft recipients of Kb-transgenic and third party skin grafts was tested on day 50 after adrenocortical transplantation. Histological sections of the adrenocortical grafts were obtained on day 100. RESULTS: Recipients of syngeneic and Kb-transgenic grafts displayed pretransplant corticosterone levels on days 20, 50, and 100 and ACTH-stimulated serum corticosterone levels similar to those of controls on day 100 after adrenocortical transplantation. In contrast, in recipients of fully MHC-mismatched grafts, corticosterone excretion was significantly reduced. In this group, 4 of 7 mice did not survive. Syngeneic skin grafts survived indefinitely in recipients of syngeneic and Kb-transgenic adrenocortical grafts, whereas Kb-transgenic and fully MHC-mismatched skin grafts were acutely rejected. Tissue sections of the adrenocortical grafts revealed vascularized cell conglomerates in syngeneic and Kb-transgenic grafts without infiltrations of mononuclear cells. Furthermore, a differentiation similar to adrenocortical organization was partly found. CONCLUSION: In conclusion, a model of cellular adrenocortical transplantation was established. The results show that syngeneic transplantation resulted in physiological corticosterone levels early after transplantation, whereas fully MHC-incompatible grafts were rejected. Recipients of Kb-transgenic grafts showed unimpaired adrenocortical function, but did not tolerize toward Kb-transgenic skin grafts. Possible mechanisms include a local immunomodulatory effect of glucocorticoids secreted by the graft and a low immunogenicity of the relatively small numbers of transplanted cells.

The numbers of leukocyte subsets in lung sections differ between intercellular adhesion molecule-1-/-, lymphocyte function-associated antigen-1-/- mice and intercellular adhesion molecule-1-/- mice after aerosol exposure to Haemophilus influenzae type-b.

In order to investigate the role of the adhesion molecules intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1) in pulmonary immunological processes, leukocyte populations were stained immunohistochemically on cryostat lung sections of ICAM-1-/- and LFA-1-/- mice. A further group of ICAM-1-/- mice was exposed to Haemophilus influenzae type-b (Hib) 24 h before being sacrificed. Comparison of the numbers of leukocytes in these groups revealed different behaviors of the leukocyte subsets: granulocytes were significantly increased in all three groups. Lymphocytes were increased in ICAM-1-/- mice, while there was no significant difference in LFA-1-/- and even a decrease in ICAM-1-/- mice after Hib exposure. Neither in ICAM-1-/- nor in LFA-1-/- mice did macrophages and dendritic cells (DCs) show significant differences to control animals. After Hib exposure, a significant elevation of DCs was observed. The following conclusions can be drawn: (1) all investigated leukocyte subsets can use ICAM-1- and LFA-1-independent pathways in the lungs of mice; (2) the pathways used by the leukocytes are cell-type specific; (3) ICAM-1 plays an important role in the enhanced recruitment of lymphocytes during Hib challenge in the lung; and (4) the alternative migratory mechanisms are able to compensate for the absence of ICAM-1 or LFA-1 or even lead to increased cell numbers. This overcompensation can be seen as a result of a balance between active alternative migratory mechanisms, which takes place in the absence of ICAM-1 or LFA-1.

Increase of inactive intra-alveolar surfactant subtypes in lungs of asthmatic Brown Norway rats.

We tested the hypothesis whether allergic airway inflammation in ovalbumin sensitized and challenged Brown Norway rats is associated with intrinsic surfactant alteration and dysfunction. The determination of intra-alveolar surfactant subtypes and alveolar edema within their original microenvironment is only possible using an ultrastructural stereological approach. Therefore both lungs of control and asthmatic rats were fixed by vascular perfusion. The volume fractions of surfactant subtypes and the epithelial surface fraction covered with alveolar edema were determined by point and intersection counting. Furthermore, lung resistance was measured by means of whole-body plethysmography. The surface activity of surfactant from bronchoalveolar lavage was determined as minimum surface tension at minimal bubble size with a pulsating bubble surfactometer. Compared with controls, in asthmatics (1) the fraction of inactive unilamellar forms was significantly increased from 56% to 66%, (2) the fraction of alveolar epithelium covered with alveolar edema visible by light microscopy was significantly increased from 0.7% to 5.0%, (3) the fraction of alveolar epithelium covered with fluid seen by electron microscopy expanded significantly from 5% to 21%, (4) lung resistance was significantly elevated from 14% to 86% and (5) surface tension was enhanced from 6 mN/m to 12 mN/m. Thus, the inflammatory process after allergen challenge of sensitized Brown Norway rats causes intra-alveolar surfactant alterations. These surfactant alterations might contribute to small airway dysfunction.

Lymphocyte dynamics in the pulmonary microenvironment: implications for the pathophysiology of pulmonary sarcoidosis.

It is generally accepted that lymphocytes play a role in sarcoidosis. Lymphocyte numbers and in particular certain subsets are increased in the bronchoalveolar lavage fluid, and these parameters have been used as indicators for prognosis. To understand the pathophysiology of sarcoidosis the localisation and kinetics of lymphocytes in the normal lung have to be known. Lymphocytes are found in different compartments of the lung: the pulmonary vascular bed with the marginal lymphocyte pool, intraepithelial lymphocytes, the lamina propria of the bronchial tree, at a young age and under certain pathological conditions the bronchus-associated lymphoid tissue, the interstitial lymphocyte pool and the lymphocytes in the bronchoalveolar space as recovered by bronchoalveolar lavage. The lymphocyte subsets differ in these compartments. The number and subset composition are influenced by the balance of immigration, regulated by adhesion molecules, local proliferation, apoptosis and migration. In sarcoidosis lymphocyte proliferation and cell death in the bronchoalveolar space are increased several fold in the lung. More studies on regulatory factors of lymphocyte kinetics are needed in the lung of sarcoidosis patients before new therapeutic strategies can be tested.