Expression of monocyte chemoattractant protein-1 in the lesional skin of systemic sclerosis

Systemic sclerosis (SSc) is a connective tissue disease with unknown etiology characterized by excessive deposition of collagen in the skin as well as various internal organs. One of the characteristic histological features is the presence of infiltrating mononuclear cells in the dermis in its early stage. As well as T cells, macrophages are implicated to play an important role in the initial pathologic changes associated with SSc by releasing fibrogenic cytokines, including transforming growth factor-beta or platelet-derived growth factor. However, the precise mechanism for increased monocyte/macrophage recruitment in the lesional skin of SSc is still not completely elucidated. Monocyte chemoattractant protein-1 (MCP-1) is a predominant monocyte chemoattractant secreted by various cells types including mononuclear cells, fibroblasts, smooth muscle cells, endothelial cells, or keratinocytes. In this study, we examined the expression of MCP-1 protein and mRNA in the lesional skin of seven patients with SSc by immunohistochemistry and in situ hybridization. Results of immunohistochemistry showed that MCP-1 was detected on infiltrating mononuclear cells and fibroblastic cells in scleroderma skin, whereas normal skin showed only minimal MCP-1 expression. We demonstrated the expression of MCP-1 mRNA in infiltrating mononuclear cells and keratinocytes in scleroderma and contact dermatitis skin. In addition, signals were also detected in fibroblasts in the lesional skin of scleroderma, whereas fibroblasts in normal skin and contact dermatitis skin did not express MCP-1 mRNA. These findings suggest that MCP-1 plays a role in recruiting monocyte/macrophages in the lesional skin of scleroderma and that activated fibroblasts in scleroderma are involved in this process.

Video-intuboscopic assistance is a useful aid to tracheal intubation in pediatric patients

PURPOSE

To evaluate the efficacy of video-intuboscopic assisted tracheal intubation in a difficult intubation setting.

METHODS

In 50 pediatric patients (mean age 12.8 +/- 3.1 yr, range 6-16 yr) a grade 3 direct laryngoscopic view was simulated. Eight certified registered nurse anesthetists without experience in endoscopic intubation performed tracheal intubation on five or more patients using the video-optical intubation stylet. Time from insertion of the tube into the oral cavity until the tip had passed the vocal cords was recorded. Failed intubation was defined as intubation >60 sec, arterial oxygen saturation <92% or esophageal intubation. Subjective degree of difficulty was asked from the operators using a Likert-scale.

RESULTS

Forty-six of the 50 patients were successfully intubated within 60 sec and without arterial oxygen desaturation. In four patients, video-assisted tracheal intubation failed due to prolonged intubation time. Intubation times ranged from 10-40 sec (median 15 sec). Mean intubation time in the first patient (24.5 +/- 17.3 sec) appeared longer than for the fifth patient (20.8 +/- 10.9 sec), but the difference was not statistically significant (P=0.87). Mean estimated degree of difficulty was 3.9 +/- 2.1. Subjective estimates of difficulty increased with intubation times (P=0.001).

CONCLUSION

The video-optical intubation stylet can be considered a valuable aid for tracheal intubation in pediatric patients with a difficult airway.

Role of stem cell factor and monocyte chemoattractant protein-1 in the interaction between fibroblasts and mast cells in fibrosis

Mast cell infiltration and accumulation is known to occur in tissue fibrosis. Increased numbers of mast cells are detected in scleroderma or hypertrophic scar skin, however, neither the role of mast cells nor the interaction of fibroblasts and mast cells in fibrosis are fully understood. A growing body of evidence indicate that mast cells are rich source of cytokines, growth factors or chemokines, which are suggested to play an important role in the induction of fibrosis. Recent in vivo and in vitro studies suggest the involvement of monocyte chemoattractant protein-1 (MCP-1), a member of the C-C chemokine family, in fibrosis. Here, we examined the effect of stem cell factor (SCF), a mast cell growth factor, on MCP-1 gene expression in a human mast cell line, HMC-1, and as well as the effect of MCP-1 on alpha1(I) collagen gene expression in human skin fibroblasts. HMC-1 cells spontaneously expressed MCP-1 mRNA transcripts, which was detectable by in situ hybridization and Northern blot analysis. Stimulation with SCF further upregulated MCP-1 mRNA expression in a time- and dose-dependent manner, and stimulation with 100 ng/ml SCF for 24 h induced a 3-fold increase of MCP-1 mRNA expression in HMC-1 cells as compared with unstimulated cells. The concentration of MCP-1 protein in the culture supernatants of 50 ng/ml SCF-stimulated HMC-1 cells (3816+/-70 pg/ml) was significantly elevated compared to unstimulated cells (2588+/-130 pg/ml) (P < 0.01), as assessed by ELISA. Adversely, MCP-1 induced alpha1(I) collagen mRNA expression in normal skin fibroblasts dose-dependently. Finally, comparative study revealed that the concentration of SCF in the culture supernatants of scleroderma fibroblasts at primary passages was significantly increased (344.6+/-182.4 pg/ml), as compared with normal skin fibroblasts (72.4+/-20.2 pg/ml) (P<0.05). These results suggest that fibroblast-derived SCF upregulates MCP-1 expression and synthesis in mast cells, which acts on fibroblasts to enhance alpha1(I) collagen mRNA expression. Our data may indicate an important interaction of fibroblasts and mast cells, via SCF and MCP-1, in the induction of fibrosis.

Human mast cell apoptosis is regulated through Bcl-2 and Bcl-XL

It is well established that human mast cell proliferation and maturation are regulated by kit ligand (stem cell factor). Little is known, however, about how these two processes are negatively regulated and thus, how mast cell number is controlled in normal and pathologic conditions. We therefore first hypothesized that SCF-dependent human mast cells would undergo programmed cell death (apoptosis) on removal of SCF as has been shown for growth factor-dependent rodent mast cells. We then examined whether SCF acts as a survival factor through the regulation of the bcl-2 family of apoptosis-regulatory genes. As hypothesized, elimination of SCF from primary peripheral blood-derived human mast cell cultures resulted in a significant apoptotic process. During apoptosis, down-regulation of the two apoptosis-regulatory proteins Bcl-2 and Bcl-XL was observed. Moreover, a deregulated expression of these two proteins was found in two human mast cell lines which are SCF-independent. Thus, SCF functions as a survival factor by repressing apoptosis of human mast cells through Bcl-2 and Bcl-XL. Deregulated expression of these antiapoptotic proteins may contribute to proliferation and accumulation of mast cells in certain forms of systemic mast cell disorders.

The speckling domain of the Wilms tumor suppressor WT1 overlaps with the transcriptional repression domain

The Wilms tumor suppressor gene WT1 encodes a zinc finger protein, expressed as different splicing variants, that has all the hallmarks of a transcription factor. The -KTS form of WT1 displays a homogeneous localization within the nucleus and has been shown to activate or repress the activity of various target genes. In contrast, the WT1(+KTS) variant demonstrates a speckled pattern of expression within the nucleus. This and its association with factors of the splicing machinery has led to the hypothesis that WT1(+KTS) might play a role in post-transcriptional processes. By the generation of a series of deletion constructs and subsequent immunofluorescence analysis, we have identified and characterized the domain which is responsible for the localization of WT1 variants in nuclear speckles. The speckling domain comprises amino acids 76-120 within the N-terminus of WT1 and is sufficient to target other proteins into distinct nuclear domains. Interestingly the WT1 speckling domain does not overlap with the domain required for interaction with the splicing factor U2AF65 but overlaps with the transcriptional repression domain. Thus our data challenge the view that association of WT1 with spliceosomes is responsible for the speckling phenotype.

Mastocytosis: recent advances in defining the disease

Mastocytosis is a rare disease characterized by a primary pathological increase in mast cells in different tissues, which may present in a variety of clinical patterns. Major advances have been made in recent years in the understanding of the pathogenesis of mastocytosis. This review is aimed at familiarizing dermatologists with these recent findings, and at exploring their possible implications for the diagnosis and treatment of the condition. The heterogeneous clinical presentation of mastocytosis is detailed with respect to the type of skin lesions, age at onset, family history, organ systems involved, associated haematological disorders and prognosis. Recent genetic findings also indicate different pathogenetic forms of mastocytosis, as adult patients and those with associated haematological diseases usually express activating mutations of the stem cell factor receptor c-kit, whereas most cases of childhood-onset and familial mastocytosis seem to lack these mutations. Despite the presence of c-kit mutations, patients with cutaneous lesions generally have a good prognosis, even when there is involvement of other organs. Some patients, particularly those with childhood-onset disease, experience spontaneous remission, mostly by puberty. c-kit mutations do not explain the initial cause of mastocytosis, and their prognostic significance is as yet unclarified, as is the pathogenesis in patients without the mutations. Furthermore, these novel findings have as yet not resulted in a more effective treatment of the cause of the disease, so that counselling, prevention of exposure to mast cell secretory stimuli, and symptomatic treatment remain the mainstays of current patient management.

Expression of mast cell growth modulating and chemotactic factors and their receptors in human cutaneous scars

In order to explore possible mechanisms involved in the previously documented turnover of mast cell subpopulations in human cutaneous scars, we have examined selected factors known to stimulate and/or modulate mast cell hyperplasia (SCF, NGF, TGFbeta1, GM-CSF) and their receptors in human cutaneous scar tissue. On immunohistochemistry, numbers of SCF- and TGFbeta1-positive cells were significantly increased in the epidermis and throughout the dermis in scars (n = 27) of varying ages (4-369 d old), compared with normal skin (n = 12). Furthermore, TRbetaRI, II, and the NGF-p75 receptors were significantly increased in the epidermis, TRbetaRI and NGF-TrkA throughout the dermis, and TRbetaRII, NGF-p75, and GM-CSFR only in the mid- and lower dermis of scars. NGF and GM-CSF expression was in contrast scarce and weak, with no differences between normal skin and scars. In tissue extracts, mRNA levels of SCF, TGFbeta1, TRbetaI and II, and both NGF-receptors, but not GM-CSFR, were significantly increased as well. TRbetaI and II were identified in up to 90% and 83%, respectively, of isolated normal skin mast cells on flow cytometry, and GM-CSFR and NGFR-p75 were identified on 70% and 73%, respectively, of avidin-positive normal mast cells on double immunofluorescence microscopy. As described before for the SCF receptor KIT, GM-CSFR and NGFR-p75 were partly or entirely downregulated on avidin-positive mast cells in scars. The marked upregulation of TGFbeta1, its type I and II receptors, and SCF suggest that these factors play a major role in the orchestration of mast cell increase in human cutaneous scars whereas the role of NGF and GM-CSF is less clear, despite the significant upregulation of their receptors.

Behavioral and pharmacological treatment methods for pregnant smokers: issues for clinical practice

Active and passive exposure to tobacco smoke are the most serious and preventable causes of poor maternal, fetal, and infant outcomes in the United States. Unfortunately, the majority of pregnant smokers do not quit smoking before or during pregnancy or after childbirth. We describe a standardized behavioral counseling model and discuss issues to consider in recommending the use of pharmacotherapy during pregnancy. Although the Food and Drug Administration no longer classifies nicotine replacement therapy (NRT) as contraindicated during pregnancy, precautions should be carefully considered for use in this population. This paper provides a synopsis of the risks of exposure to tobacco smoke during pregnancy and the postpartum; estimates the population at risk and the potential for increased cessation if effective health education methods during pregnancy were routinely provided; presents a meta-analysis of "best practice" patient education methods for pregnant smokers; and estimates the number of pregnant heavy smokers who might be eligible for NRT. We suggest five issues for the physician to consider before recommending NRT medications to pregnant patients who are heavy smokers. The judicious use of NRT medications may significantly reduce harm to the infants of heavy smokers. More evidence derived from large population-based research, however, is needed to provide guidance to the physician about NRT eligibility, dose, scheduling, and effectiveness in clinical practice.

Biochemical and molecular characterization of corn (Zea mays L.) root elongases

Root surfaces are protected against the soil environment by the deposition of lignin and suberin. In order to obtain more insight into the regulation of root suberin biosynthesis, elongases from primary roots of corn (Zea mays L.) seedlings were characterized. Elongase activities (acyl-CoA and ATP-dependent) were located in the microsomal fraction of the root cells. C(20), C(22) and C(24) fatty acids were detected as primary products of elongases. Preferred substrates of the acyl-CoA elongases were C(18:0)-CoA and C(20:0)-CoA. Applying a molecular approach, using PCR and degenerate primers derived from the sequences of known leaf and seed 3-ketoacyl-CoA synthases (KCSs), catalysing the first step of very-long-chain fatty acid synthesis, the cDNA of a putative root KCS was obtained showing high homology to known leaf and seed KCSs at the DNA and amino acid levels. Thus, our approach provides the first direct evidence for the presence and the activity of root elongases in Z. mays. Ongoing research is focusing on the molecular analysis and the regulation of KCS expression in roots in reaction to different environmental stimuli.

Metabolite monitoring in plants with double-quantum filtered chemical shift imaging

1H spectroscopic imaging in combination with double-quantum filtering with magnetic field gradients is used for in vivo applications in humans and animals. Because of its high selectivity and strong reduction of water signal it is also a useful tool for monitoring the distribution of specific metabolites in plants. The development and application of a double-quantum selective spectroscopic imaging sequence for detecting the sucrose distribution in the stem of sugar cane (Saccharum officinarum L.) is described. The results show that local differences in sucrose distribution can be detected non-invasively with a resolution of 0.4x0.4x6 mm(3) to 0.645x0.645x6 mm(3).

[Reactivation of herpes virus infections by vaccination: evidence or coincidence?]

Varicella zoster and herpes simplex viruses cause latent infections by persisting in human cells. Reactivation has been associated with increasing age, immunosuppression, cancer, stress, fever, exposure to ultraviolet light, and tissue damage. Based on three cases reported to the Swiss Drug Monitoring Centre SANZ, we postulated previously that vaccinations may trigger reactivation of herpes virus infections due to vaccine-induced immunomodulation. In the meantime, 10 new cases of reactivated herpes virus infections soon after vaccinations have been reported. They involved 5 women and 5 men with an age range between 16 and 60. In only one case had a trauma preceded, otherwise healthy subjects with no known relevant comorbidity were vaccinated. The clustering of reports after publication points to a previous underreporting of similar cases. This may be explained by the fact that both vaccinations and reactivations of herpes virus infections are frequent, and a causal link is not suspected. However, these new cases do not prove causality, and extensive epidemiological or experimental studies are needed to elucidate the possible link between vaccination and reactivation of herpes virus infections.

Measurement of venous outflow pressure in the central retinal vein to evaluate intraorbital pressure in Graves' ophthalmopathy: a preliminary report

PURPOSE

To evaluate the intraorbital pressure in patients with Graves' ophthalmopathy (GO) in relation to the intraocular pressure (IOP) and proptosis and to find out whether optic nerve compression is predictable.

METHODS

The venous outflow pressure (VOP) in the central retinal vein was measured by the perviously described technique of oculodynamometry.1 Since the central retinal vein passes through the orbit, the VOP cannot be lower than the intraorbital pressure if outflow is to be guaranteed. The IOP was measured either in primary position or with slight chin elevation to avoid restriction of the globe. Fifty-seven patients underwent a complete ophthalmologic examination, including VOP measurements, Hertel exophthalmometry and visual fields.

RESULTS

The IOP in primary position ranged between 10 and 29 mmHg and in most (n=54) cases the VOP was 0-4 mmHg higher than the IOP. These patients had neither scotomas nor visual deterioration during an observation period of up to 2 years. In those cases (n=3) where the difference between IOP and VOP was 35 mmHg, the patients developed scotomas and visual deterioration and had to be treated (high-dose steroids or orbital decompression). The elevation in VOP did not correlate with the degree of proptosis. In one unilateral case, treatment of high IOP (32 mmHg) with dorzolamide drops led to a decrease in visual acuity of two lines, inferior field depression and relative afferent pupillary defect. The difference between IOP and VOP was 10 mmHg. Stopping treatment normalized visual function, the IOP rose to its original level and the difference between IOP and VOP was 4 mmHg.

CONCLUSION

The increased IOP in GO is not caused by primary glaucoma but by elevated intraorbital pressure. The difference between IOP and VOP must be <5 mmHg to guarantee normal perfusion. We interpret these findings to suggest that loss of visual acuity and visual field defects may not only be caused by optic nerve compression at the apex but also by deterioration of optic nerve head perfusion.

[Immediate hypersensitivity reactions to parenteral glucocorticoids? Analysis of 14 cases]

Immediate hypersensitivity reactions to parenteral glucocorticoids are rare but often serious and life-threatening. In the medical literature some hundred case reports of corticoid hypersensitivity after parenteral administration have been published. The pathomechanism may be immunological or non-immunological in nature and the reaction can be due to the steroid itself or to the excipients. We report on 14 suspected hypersensitivity reactions occurring in 13 patients immediately after parenteral glucocorticoid administration. These cases were reported to the Swiss Drug Monitoring Centre SANZ between 1981 and 1999. 5 out of 26 preparations available in Switzerland and 4 out of the 6 glucocorticoids used for parenteral administration were involved (beta-methasone, methylprednisolone, prednisolone, triamcinolone). 9 reactions were life-threatening: 3 patients experienced an acute asthma attack and 6 a serious anaphylactic reaction including shock. Risk factors were known in 10 patients: allergy was mentioned in 6 patients, and asthma and aspirin-sensitivity in 2 patients each. In 2 patients a clinically relevant cross-reaction with another glucocorticoid was known, while 6 patients tolerated another steroid without problems. Only in 6 cases were skin tests performed: 3 were positive for the preparation, and in one of these cases the skin test was positive for the steroid itself. In 2 cases the hypersensitivity reaction could be traced back to the additive carboxymethylcellulose. Practitioners should be aware of hypersensitivity reactions to glucocorticoids whenever there is a worsening of the clinical status in spite of maximal steroid therapy.

Monocyte chemoattractant protein-1 enhances gene expression and synthesis of matrix metalloproteinase-1 in human fibroblasts by an autocrine IL-1 alpha loop

Monocyte chemoattractant protein-1 (MCP-1), a member of the C-C chemokine superfamily, has recently been shown to be involved in the pathogenesis of tissue fibrosis. In vitro studies demonstrated that MCP-1 up-regulates type I collagen gene expression via endogenous production of TGF-beta in rat lung fibroblasts. We here show that recombinant human MCP-1 affects gene expression of interstitial collagenase (matrix metalloproteinase-1 (MMP-1)) in primary human skin fibroblasts and a stable fibroblast cell line. MMP-1 mRNA was induced by MCP-1 (10 ng/ml) as early as 6 h and reached a maximal expression at 24 h. MCP-1 also caused an increase of MMP-2 mRNA expression in both types of fibroblasts at 48 h. Interestingly, tissue inhibitor of metalloproteinase-1 (TIMP-1) mRNA was also up-regulated by MCP-1, and TIMP-1 mRNA expression peaked at 48 h in both types of fibroblasts. Immunoblot analysis demonstrated increased levels of MMP-1 and TIMP-1 protein in the culture supernatants of primary fibroblasts stimulated with MCP-1. In addition, MCP-1 strongly induced IL-1 alpha mRNA expression in dermal fibroblasts in parallel with the induction of MMP-1. Preincubation with IL-1 receptor antagonist almost completely abrogated the expression of MMP-1 mRNA, and partially inhibited MMP-1 synthesis induced by MCP-1. Transient transfection of primary skin fibroblasts with a MMP-1 promoter-reporter construct indicated a dose-dependent increase in promoter activity by MCP-1 stimulation. These data demonstrate that MCP-1 up-regulates MMP-1 mRNA expression and synthesis in human skin fibroblasts at a transcriptional level and provide evidence that this is mediated by an IL-1 alpha autocrine loop.

Pediatric mastocytosis

Pediatric mastocytosis presents with heterogeneous cutaneous lesions and symptoms that are caused by increased numbers of tissue mast cells. In contrast with adult patients with mastocytosis, the course of pediatric patients is usually transient. Therefore, it has long been speculated that pediatric and adult mastocytosis may be based on different pathogenetic mechanisms. Indeed, new genetic findings now indicate differences in the pathogenesis. Adult patients usually express activating mutations of the growth factor receptor c-kit. Most children lack these mutations but sometimes carry other inactivating mutations of c-kit. Only children with progressive mastocytosis seem to express the activating mutations seen in adults. Causal treatment is not yet available, but H1 and H2 antihistamines may provide relief of symptoms. It is important to counsel patients and their parents carefully to avoid triggers that induce systemic mast cell degranulation.

Norditropin SimpleXx: a liquid human growth hormone formulation, a pen system and an auto-insertion device

Patient compliance is of vital importance for the outcome of any medical therapy. Compliance is especially a problem in long-term treatment of non-life threatening diseases, such as growth retardation in children. Until recently, all human growth hormone (hGH) products required a reconstitution process. Norditropin((R)) SimpleXx(TM) is a liquid formulation of the biosynthetic hGH product Norditropin((R)), and, together with an improved NovoPen((R)) 1.5, NordiPen(TM), and an auto-insertion device, PenMate(TM)/NordiPenMate(TM), it has been developed in order to ease the injection process for patients. A randomized, open, multicentre, crossover trial compared Norditropin((R)) SimpleXx(TM)/improved NovoPen((R)) 1.5 with freeze-dried Norditropin((R)) PenSet((R))/Nordiject((R)). A total of 67 children with GH deficiency, aged 5-18 years, were treated with either Norditropin((R)) SimpleXx(TM) for 6 weeks followed by Norditropin((R)) for 6 weeks or the opposite (sequences I and II, respectively). Acceptability/convenience and pain perception were evaluated by questionnaire after each period. The function and handling of the PenMate(TM) were evaluated in a Dutch trial by 27 GH-treated children with intrauterine growth retardation, aged 4-16 years, and their parents. All children were accustomed to using the Nordiject((R)) pen. The evaluation of the PenMate(TM) was based on a questionnaire. A similar trial was conducted in England, in which the NordiPen(TM) and the NordiPenMate(TM) were evaluated by 25 GH-treated children and their parents. Norditropin((R)) SimpleXx(TM) was found to be easier to inject by 64% of the children, and 98% of the children found the system easier to use overall. There was no difference in pain perception between the two administration systems, as judged by questionnaires and visual analogue scale score. Three out of four patients preferred to continue treatment with Norditropin((R)) SimpleXx(TM). The safety profiles of the two systems were similar. In the Dutch trial, the PenMate(TM) was found to be easy and safe to handle, even for very young children (aged 4-5 years). Of patients who took a long time to get used to the injections, 73% found that the new pen would help. A total of 88% of the children would prefer to use the PenMate(TM) in the future. Positive results of the handling tests were also reported in the British trial. The use of Norditropin((R)) SimpleXx(TM) and the auto-insertion device may improve patient compliance.

Cervical neoplasia originating from the vagus nerve in a dog

An eight-year-old intact male Bernese mountain dog was referred with a history of chronic vomiting, coughing and signs of respiratory distress. Other historical findings included lethargy, weight loss and choking. On presentation, clinical findings were Horner's syndrome, ipsilateral laryngeal hemiplegia, coughing, gagging, respiratory distress and vomiting. Lateral cervical radiographs showed ill-defined mineralisation in the soft tissue ventral to the third cervical vertebra, while ultrasonography of the neck revealed a well marginated heterogeneous mass with focal hyperechogenic lesions and acoustic shadowing. Results of an ultrasound-guided fine needle aspirate suggested neoplasia. At necropsy, a large tumour was detected in the ventral cervical region, originating from the right vagosympathetic trunk. In view of the infiltrating pattern, the cellular pleomorphism and the numerous mitoses on histopathological examination, the tumour was classified as a malignant peripheral nerve sheath tumour.

Mast cells enhance contraction of three-dimensional collagen lattices by fibroblasts by cell-cell interaction: role of stem cell factor/c-kit

Reorganization of the extracellular matrix is important in many biological and pathophysiological processes, including tissue remodelling, wound healing, or cancer metastasis. The ability of cultured fibroblasts to reorganize and contract three-dimensional type I collagen gels is regarded as an in vitro model for this process. In tissue fibrosis, complex interactions among fibroblasts, inflammatory cells and the extracellular matrix are taking place. Mast cells have often been discussed to play a role in several fibrotic conditions including scleroderma, scar formation, or wound healing. In this study, we examined the effects of mast cells on contraction of collagen lattices. The results demonstrate that co-culture of dermal fibroblasts with a human mast cell line (HMC-1) significantly enhanced contraction of the three-dimensional collagen lattices, whereas mast cells alone failed to contract the gel. Addition of culture supernatants of mast cells did not enhance the speed of gel contraction, indicating the importance of cell-cell contact. Morphological analysis showed that mast cells were incorporated into the lattices. Histological examination also demonstrated that within the lattices, mast cells were localized in close contact to, or attached to, fibroblasts. As fibroblasts and mast cells are known to attach via stem cell factor (SCF)/c-kit interaction when co-cultured in monolayers, we also examined the effect of antibodies against SCF and c-kit in this system. Addition of both antibodies inhibited gel contraction up to 70%. In contrast, antibodies against interleukin-4 (IL-4) and IL-4 receptor did not affect gel contraction. These results indicate that mast cells enhance fibroblast-mediated contraction of collagen lattices via direct cell-cell contact, mediated in part by SCF/c-kit interactions.

[Potential drug interactions and number of prescription drugs with special instructions at hospital discharge]

OBJECTIVE

Up to 6% of all hospitalizations are due to adverse drug reactions and 20% of these are caused by drug-drug interactions. There is only little information on the prescription frequency of drug-combinations with the potential to induce dangerous drug-drug interactions and drugs with the need for special patient instruction (e.g. inhalers). The aim of our study was to investigate the frequency of such drug prescriptions at hospital discharge.

PATIENTS AND METHODS

In a retrospective, descriptive study drug prescriptions of 100 patients discharged consecutively from the department of internal medicine of a 300 bed-hospital were analysed. Possible drug-drug interactions were detected using a special computer program. Furthermore, the number of prescriptions warranting patient instruction such as anticoagulants, antidiabetics, hormones, immunosuppressive drugs, chemotherapeutics, antituberculotic and antiepileptic drugs as well as inhalatives and injections was recorded.

RESULTS

The mean age of the 100 patients (61 men, 39 women) was 61.7 years, the mean duration of the hospital stay was 9.2 days. At discharge, patients took an average of 3.5 different drugs. Half of the patients were given drug-combinations with the potential for drug-drug interactions, whereby 5% were at risk for the development of interactions of severe and 42% of intermediate degree. All drug-combinations with potentially severe interactions were prescribed deliberately. 31% of all patients took medications with the need for special education, with inhalatives being the most frequent. The prescription of drugs with potential interactions and the necessity for special patient instruction was more frequent in the elderly.

CONCLUSIONS

Drug-combinations with the potential of harmful interactions and drugs with the requirement for special patient instruction are frequently prescribed at hospital discharge. The frequency of prescribing these drugs increases with age. Detection of potentially dangerous drug-drug interactions is simplified by special computer programs. Careful patient instruction about the use of certain drugs is a key issue to improve patient compliance and to guarantee an optimal treatment effect.