Ionotropic GABA receptors with mixed pharmacological properties of GABAA and GABAC receptors

Ionotropic gamma-aminobutyric acid (GABA) receptors form a large family of molecular isoforms with distinct properties. We have characterized a distinct new type of GABA receptors in CA1 pyramidal cells in rat hippocampal slices. Somatic application of GABA induced currents which were partially suppressed by (1,2,5,6-tetrahydropyridin-4-yl)methylphosphinic acid (TPMPA), a specific antagonist of GABA(C) receptors. This sensitivity was enhanced when we evoked the currents by the GABA(C) receptor agonist cis-4-aminocrotonic acid (CACA). However, both GABA- and CACA-evoked currents were sensitive towards bicuculline and thus lack the defining feature of GABA(C) receptors, which are insensitive towards this antagonist. Spontaneous miniature post-synaptic currents (mIPSCs) revealed a similar pharmacological behaviour. We conclude that juvenile CA1 pyramidal cells express a fraction of ionotropic GABA receptors with mixed pharmacological properties of both, GABA(A) and GABA(C) receptors.

[Urticaria. Classification and diagnosis]

Urticaria belongs to the most frequent dermatologic diseases. Although the pathogenesis of urticaria is not fully understood, systematic studies in recent years have identified the most important triggering factors of the different forms of urticaria. Based on these results, it is recommended to restrict diagnostic procedures in acute urticaria to history and physical examination, while in chronic urticaria, one should exclude drugs, infections, pseudoallergic reactions, and autoimmune processes as causes. For the diagnosis of physical urticaria, standardized provocation test are recommended.

Pyoderma gangraenosum: erfolgreiche Therapie mit topischer Applikation von Cyclosporin A

Pyoderma gangraenosum (PG), eine seltene, ulzerierende Hauterkrankung, ist wahrscheinlich durch vaskulitische Prozesse verursacht. In ca. 20 bis 70% der Fälle ist PG mit einer Grunderkrankung assoziiert, am häufigsten mit chronisch-entzündlichen Darmerkrankungen und Erkrankungen des rheumatischen oder hämatologischen Formenkreises. PG kommt auch posttraumatisch als Pathergiephänomen vor.

Der größte Teil der verschiedenen Therapieansätze bei Pyoderma gangraenosum beruht auf systemischer Gabe von Immunsuppressiva. Wir berichten über unsere Therapieerfahrungen mit topischer Applikation von Cyclosporin-A-Lösung.

Evidence for altered mast cell proliferation and apoptosis in cutaneous mastocytosis

BACKGROUND

Mastocytosis presents as a focal or generalized increase of mast cells, particularly in the skin, but also in other organs. Activating mutations of KIT (formerly c-kit), the receptor of the mast cell growth factor stem cell factor (SCF), appear to play a key role in the pathogenesis of sporadic adult onset mastocytosis. However, these mutations are not present in childhood-onset and familial mastocytosis and also fail to explain the heterogeneity of adult-onset disease. Other factors such as prolonged survival of mast cells may therefore participate in causing and modulating the pathological increase of mast cells in mastocytosis.

OBJECTIVES

To examine the expression of proliferation and apoptosis markers in the mast cells of cutaneous mastocytosis lesions in order to gain further insight into the pathogenesis of mastocytosis.

METHODS

Lesional cutaneous biopsies from eight infants with solitary mastocytomas, five children with multiple mastocytomas, 11 children with generalized urticaria pigmentosa, 12 adults with urticaria pigmentosa, and skin from seven normal controls were used in this study. Serial sections were stained with toluidine blue to quantify mast cell numbers and with antibodies against the proliferation marker Ki67 protein, the tumour suppressor protein p53, and the inhibitor of cyclins and cyclin-dependent kinases p21WAF1/CIP1, using the alkaline phosphatase antialkaline phosphatase technique. The terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labelling (TUNEL) method was used to assess apoptosis.

RESULTS

Cutaneous mast cell counts were significantly increased in all patient sections, particularly in childhood lesions, and similarly, a small but significant increase of proliferation was found in the lesional mast cells of all patients. Enhanced mast cell numbers and proliferation was associated with a significant decrease of TUNEL staining, particularly in mastocytomas. p53 expression was highly variable, with an overall significant increase in all patient skin mast cells, whereas p21 expression was barely observed at all.

CONCLUSIONS

These findings further support the concept that an imbalance of mast cell proliferation and apoptosis is prevalent in mastocytosis lesions that may account in part for the increased focal mast cell accumulation in this condition.

A teledermatological approach to enhance diagnostic accuracy in dermatohistopathology

We determined whether digital photographs of skin lesions could enhance diagnostic accuracy in dermatohistological evaluations. Two dermatohistopathologists examined 375 unsorted consecutive cases. On a standardized questionnaire they recorded whether the final diagnostic interpretation would be improved by the availability of digital images of the skin lesions. In 101 cases (27%) they said that digital photographs would be helpful. Subsequently, 30 histological analyses were performed with and without digital photographs of the skin lesions. Presentation of digital photographs reduced the number of differential diagnoses significantly, from a median of 3 to 2. Ratings of ability to make a single definitive diagnosis increased significantly with the presentation of digital photographs. Enhancement of information given by the digital images was scored a median of 6 (on a scale of 0-10, with higher scores reflecting greater enhancement). Digital photographs of skin lesions are likely to refine diagnostic accuracy in histopathology.

One year follow up of macular translocation with 360 degree retinotomy in patients with age related macular degeneration

AIM

To evaluate the benefits of macular translocation with 360 degree retinotomy in patients with exudative age related macular degeneration (ARMD).

METHODS

A consecutive interventional case series was performed on patients who underwent macular translocation between June 1997 and January 2000 at the department of ophthalmology, University of Aachen, Germany. A retrospective pilot study was set up with a minimum follow up of 12 months in 39 consecutive patients with subfoveal choroidal neovascularisation secondary to ARMD. The surgical technique included pars plana vitrectomy, induction of retinal detachment, 360 degree retinotomy, removal of the choroidal neovascular membranes (CNVM), macular translocation, peripheral laser retinopexy, and silicone oil endotamponade.

RESULTS

18 patients showed predominantly occult CNVM, six patients had predominantly classic CNVM, and 15 showed subretinal haemorrhage. At the 12 month follow up 13 patients (33%) showed an improvement in visual acuity of more than three lines (logMAR scale), 18 patients (46%) retained stable visual acuity with a change of equal or less than three lines (logMAR scale), and eight patients (21%) showed a decrease in visual acuity of more than three lines (logMAR scale). Recurrence of CNVM was observed in three (8%) eyes at 5-11 months postoperatively. Other complications included proliferative vitreoretinopathy with retinal detachment (n=10), peripheral epiretinal membranes (n=9), macular pucker (n=2), corneal decompensation (n=2), and hypotony (n=11). 18 patients (46%) complained about persistent diplopia.

CONCLUSION

Macular translocation surgery is able to maintain or improve distant vision in the majority of patients with exudative ARMD. Proliferative vitreoretinopathy and diplopia are the two major complications. A prospective randomised controlled trial comparing macular translocation with observation for patients with the occult form of exudative ARMD may be justified.

Hyperbaric oxygen: does it promote growth or recurrence of malignancy?

It has been a concern that a therapeutic modality recommended as an adjunct to healing and administered to promote proliferation of fibroblasts, epithelial cells and blood vessels in a wound could also lead to proliferation of malignant cells and angiogenesis in a malignant tumor. The first reported concern that hyperbaric oxygen (HBO2) might have cancer growth enhancing effects appeared in a paper by Johnson and Lauchlan in 1966. In a series of patients treated with HBO2 radiosensitization, they reported a more frequent than expected incidence of metastases and an unusual pattern of metastases. The published literature from clinical reports, animal studies and cell culture studies are reviewed. Putative mechanisms whereby HBO2 could have carcinogenic effects are discussed. The processes of angiogenesis in wound healing and in cancer growth are compared and contrasted. In vitro, in vivo and clinical studies strongly suggest no more than a neutral effect of HBO2 on tumor growth. In fact some studies suggest a negative impact of HBO2 on malignant progression or formation. For angiogenesis, similarities in wound healing and cancer are striking but significant differences are found including the relative importance of angiogenic factors and the process of cessation of angiogenesis. Tumors that grow in hypoxic environments are more prone to metastases and more lethal to the patient. They are also more likely to mutate toward resistant genotypes. Discussion of postulated mechanisms of carcinogenesis including free radical and immunosuppressive effects points out why they are not likely to enhance or cause cancer growth or initiation. In conclusion, the published literature on tumor angiogenesis mechanisms and other possible mechanisms of cancer causation or accelerated growth provides little basis for HBO2 to enhance malignant growth or metastases. A history of malignancy should not be considered a contraindication for HBO2 therapy.

[Suspected neurological side-effects of tick-borne meningoencephalitis vaccination: experiences of the Swiss Adverse Drug Reaction Reporting Center]

The number of patients affected by tick-born encephalitis (TBE) in Switzerland has increased in the last years and an extension of the endemic foci of TBE has been observed. Therefore, active immunization by TBE vaccination has become more important. The possible adverse vaccine reactions have to be known as exactly as possible. The Swiss Drug Monitoring Center SANZ received from 1987 until June 2000 33 spontaneous cases reporting on 39 neurological adverse reactions in a close temporal relationship with a TBE vaccination and a suspected causal relationship. The following adverse reactions were reported most frequently: headache in 36%, neuropathy in 18% and meningeal irritation in 13%. Twelve out of 33 patients were hospitalized due to the adverse reaction. All neurological reactions were reversible. The spontaneous reporting scheme of the SANZ does not allow to calculate the incidence of neurological reactions after TBE vaccination. In general, adverse neurological reactions after TBE vaccination seem to be rare. According to the experiences of SANZ all reported neurological reactions were reversible.

Mastocytosis: review of clinical and experimental aspects

Mastcytosis is a rare disease characterized by an abnormal increase of mast cells in tissues. The skin is the organ most frequently involved, but mast cells also accumulate in the bone marrow, gastrointestinal tract, lymph nodes, spleen, and liver. Recent studies suggest that activating mutations of c-kit, a protooncogene encoding for the receptor (kit) of stem cell factor, are a possible cause of some forms of mastocytosis. In addition, an increased rate of chromosomal aberrations has been found. Despite significant advances in research on mastocytosis, curative treatment is not yet available. Current management is based on avoidance of mediator-releasing triggers and symptomatic treatment.

Drug-induced bronchospasm: analysis of 187 spontaneously reported cases

BACKGROUND

The Swiss Drug Monitoring Center (SANZ) uses a systematic approach to the collection of spontaneously reported individual cases on suspected adverse drug reactions (ADRs). Spontaneous reporting schemes are designed to detect new, rare and unexpected ADRs and to act as an early warning system but there is a tendency to overreport severe reactions.

OBJECTIVES

The aim of the study was to determine drug-induced episodes of bronchospasm, their seriousness and predisposing risk factors. An ADR is classified as serious if the reaction results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability or incapacity.

RESULTS

From 1986 to 1995 SANZ received 8,191 case reports of suspected ADRs. In 187 cases (2%) bronchospasm was reported. In 55% of these cases the reaction was regarded as serious. Analgesics and nonsteroidal anti-inflammatory drugs (NSAIDs) were reported most frequently and were involved in 24% of the cases of which 64.5% were classified as serious. In three cases a lethal outcome was reported after intravenous administration of metamizol. Anti-infectious agents were implicated in 18% (52% serious), cardiovascular drugs in 11% (50% serious), drug formulation agents in 9% (41% serious), vaccines and immunoglobulins in 5.5% (50% serious), and plasma volume expanders in 5.5% (80% serious). Other drug groups were involved in 27% of the cases. About 50% of patients experiencing bronchospasm after NSAIDs, pharmaceutical formulation agents, vaccines and immunoglobulins had predisposing risk factors such as asthma, atopy or drug allergy. In other drug groups a predisposing factor was identified in 27% or less.

CONCLUSION

Drug-induced bronchospasm is frequently reported with NSAIDs, anti-infective agents, cardiovascular drugs and excipients with a high proportion of serious reactions.

Comparison of six in-house tests for the rapid diagnosis of feline immunodeficiency and feline leukaemia virus infections

Six rapid tests for the diagnosis of feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV) infections which have recently been introduced in Europe for use in small animal practice were compared. Eight hundred serum samples were tested and those reacting FIV-positive in at least one of the tests were confirmed by Western blot, and those reacting FeLV-positive were confirmed by virus isolation. The specificity and sensitivity of each test and the quality of the results produced were compared.

Use of angulated video-intubation laryngoscope in children undergoing manual in-line neck stabilization

Laryngeal views obtained during direct laryngoscopy with and without manual in-line neck stabilization (MILNS) and during video-assisted intubation with MILNS using the angulated video-intubation laryngoscope were assessed in 100 paediatric patients (aged 0.25-17.3 yr). Visualization of the larynx (Cormack and Lehane score) as well as time taken for video-assisted tracheal intubation by six nurses and four resident anaesthetists not experienced in the technique were recorded. Cormack and Lehane scores were significantly worse during direct laryngoscopy when MILNS was applied. Video-assisted visualization of the larynx during MILNS produced scores, which were as good or better than those observed during direct laryngoscopy alone. Intubation times ranged from 19-75 s (mean 35 (SD 13.4); median 32).