Cerebellar infarction affects visual search

Recent studies have discussed the role of the cerebellum in not only motor but also cognitive functions, and in particular, fronto-executive operations. Similar to a previous study on hemineglect patients, we recorded eye movements during a visual search task to investigate patients with isolated infarction of the cerebellum compared with controls. Patients showed longer search durations, associated with mild saccadic dysmetria, longer single fixation durations and a higher number of repeated fixations of items. Systematic search strategies were preserved, but less frequent in patients. In conclusion, though basic mechanisms of visual search including spatial memory were not affected by cerebellar lesions, patients' search behaviour was slower and less efficient, indicating a mild deficit of visual attention and motor planning.     

Diagnostic image (105). A woman with painful nodules. Infection with O. volvulus

A 17-year-old woman from the Democratic Republic of Congo presented with painful nodules on the legs and malaise. An infection with Onchocerca volvulus was diagnosed.     

Borrelia burgdorferi induces chemokines in human monocytes.

Lyme disease is clinically and histologically characterized by strong inflammatory reactions that contrast the paucity of spirochetes at lesional sites, indicating that borreliae induce mechanisms that amplify the inflammatory response. To reveal the underlying mechanisms of chemoattraction and activation of responding leukocytes, we investigated the induction of chemokines in human monocytes exposed to Borrelia burgdorferi by a dose-response and kinetic analysis. Lipopolysaccharide (LPS) derived from Escherichia coli was used as a positive control stimulus. The release of the CXC chemokines interleukin-8 (IL-8) and GRO-alpha and the CC chemokines MIP-1alpha, MCP-1, and RANTES was determined by specific enzyme-linked immunosorbent assays, and the corresponding gene expression patterns were determined by Northern blot analysis. The results showed a rapid and strong borrelia-inducible gene expression which was followed by the release of chemokines with peak levels after 12 to 16 h. Spirochetes and LPS were comparably effective in stimulating IL-8, GRO-alpha, MCP-1, and RANTES expression, whereas MIP-1alpha production preceded and exceeded chemokine levels induced by LPS. Unlike other bacteria, the spirochetes themselves did not bear or release factors with intrinsic chemotactic activity for monocytes or neutrophils. Thus, B. burgdorferi appears to be a strong inducer of chemokines which may, by the attraction and activation of phagocytic leukocytes, significantly contribute to inflammation and tissue damage observed in Lyme disease.     

Prevalence of basidiospore allergy in the Pacific Northwest

Mold spore-induced respiratory allergy has been incompletely studied, and only a limited number of Fungi Imperfecti are well established as aeroallergens. Basidiomycetes, a complex and common group of fungi, which include mushrooms, rusts, smuts, brackets, and puffballs, have not been well studied. Although basidiospores can be present in high atmospheric concentrations, little is known of their aeroallergen potential. To examine this question, we performed skin prick and RASTs in 33 adult residents of Washington State using a panel of 15 common inhalant allergents that included four Fungi Imperfecti and 15 basidiospore extracts. Thirty-one of 33 (94%) subjects had positive immediate reactions to two or more common inhalants. Nine of 33 (27%) subjects responded to at least one Fungi Imperfecti; reactions were most common to Aspergillus sp. (21%), and least common to Penicillium sp., which were positive in 6%. Positive responses to basidiospore extracts were observed in 10 of 33 (30%) subjects. The prevalence of basidiospore reactivity was similar to that of Fungi Imperfecti, ranging from 18% for Scleroderma sp. to 6% for four different spore extracts. These results demonstrate that a significant number of subjects with respiratory allergies have skin test reactivity to basidiospore extracts, suggesting that these spores could be important aeroallergens in the Pacific Northwest.     

Studies of neutrophil chemotactic factor of anaphylaxis in metabisulfite sensitivity

The mechanism(s) of adverse reactions to sulfites remains unclear. To determine whether mast cell degranulation is involved in sulfite sensitivity, we performed single-blind, placebo-controlled oral aqueous challenges with potassium metabisulfite in 13 patients with histories suggestive of sulfite sensitivity. Ten patients were also skin tested with potassium metabisulfite at 10 mg/mL and all had negative reactions. Serum samples were obtained from all the patients before the challenge and for 180 minutes after the challenge. The samples were tested for the presence of neutrophil chemotactic factor of anaphylaxis, using both a 51chromium microchamber chemotaxis assay and a leukocyte polarization technique. Six of 13 patients had positive challenges as defined by a fall equal to or greater than 20% in their forced expiratory volume in one second. No significant increase in neutrophil chemotactic factor activity was detected in the postchallenge serum samples from patients who experienced positive or negative challenges. We conclude that sensitivity to aqueous metabisulfite is not associated with mast cell degranulation in metabisulfite skin test-negative patients.