Neurotoxic envenoming by an immigrant spider (Steatoda nobilis) in southern England.

A young woman was bitten on the shoulder by a female Steatoda nobilis spider, in Worthing on the south coast of England. She noticed intense radiating pain, local sweating (indicating parasympathetic stimulation) and feverishness. This immigrant species from the Canary Islands has established itself along the south coast of England in recent years. Like the related Mediterranean species S. paykulliana, S. nobilis may be of medical importance and deserves further study.     

Effect of sequence polymorphisms on performance of two real-time PCR assays for detection of herpes simplex virus

Herpes simplex virus (HSV) is the most common cause of acquired, sporadic encephalitis in the United States. PCR identification of HSV in spinal fluid has become the diagnostic gold standard due to its sensitivity and potential for speed, replacing other methods such as culture. We developed a real-time PCR assay to detect HSV, using a new type of hybridization probe, the Eclipse probe. In this study, we ran 323 samples (171 positives and 152 negatives) with the Eclipse real-time PCR assay and compared these results with another PCR assay using gel detection. The real-time assay agreed with our reference method for 319 out of the 323 samples tested (99%). Using two different real-time PCR platforms, we discovered that SNPs within the amplicon's probe binding region that are used to distinguish HSV-1 from HSV-2 can decrease assay sensitivity. This problem is potentially a general one for assays using fluorescent probes to detect target amplification in a real-time format. While real-time PCR can be a powerful tool in the field of infectious disease, careful sequence evaluation and clinical validation are essential in creating an effective assay.     

Co-localization of calcitonin gene-related peptide-like immunoreactivity with substance P in cutaneous, vascular and visceral sensory neurons of guinea pigs

Calcitonin gene-related peptide (CGRP) has been immunohistochemically co-localized with substance P (SP) in capsaicin-sensitive, varicose axons supplying the skin, viscera and cardiovascular system of the guinea pig. After treatment with colchicine in vitro, 82% of SP neurons in the dorsal root ganglia contained CGRP-like immunoreactivity while 96% of CGRP neurons were immunoreactive for SP. Both CGRP- and SP-like immunoreactive material are transported peripherally and centrally from dorsal root ganglia. Thus, in tissues such as the gut where there are intrinsic nerves containing SP but lacking CGRP, CGRP-like immunoreactivity is a useful means of specifically labelling axons of most sensory neurons containing SP.     

Spatial attention modulates early face processing

It is widely reported that inverting a face dramatically affects its recognition. Previous studies have shown that face inversion increases the amplitude and delays the latency of the face-specific N170 component of the event-related potential (ERP) and also enhances the amplitude of the occipital P1 component (latency 100–132 ms). The present study investigates whether these effects of face inversion can be modulated by visual spatial attention. Participants viewed two streams of visual stimuli, one to the left and one to the right of fixation. One stream consisted of a sequence of alphanumeric characters at 6.67 Hz, and the other stream consisted of a series of upright and inverted images of faces and houses presented in randomized order. The participants’ task was to attend selectively to one or the other of the streams (during different blocks) in order to detect infrequent target stimuli. ERPs elicited by inverted faces showed larger P1 amplitudes compared to upright faces, but only when the faces were attended. In contrast, the N170 amplitude was larger to inverted than to upright faces only when the faces were not attended. The N170 peak latency was delayed to inverted faces regardless of attention condition. These inversion effects were face specific, as similar effects were absent for houses. These results suggest that early stages of face-specific processing can be enhanced by attention, but when faces are not attended the onset of face-specific processing is delayed until the latency range of the N170.     

Immunocytochemical localisation of katacalcin, a calcium-lowering hormone cleaved from the human calcitonin precursor

Katacalcin is a newly discovered calcium-lowering hormone predicted from the nucleotide sequence of a cloned cDNA derived from human calcitonin mRNA. The aim of the study was to localise katacalcin by immunocytochemistry at both light and electron microscope levels. Antisera to synthetic katacalcin and calcitonin were used to investigate 8 cases of medullary thyroid carcinoma and 6 normal human thyroids (3 adult and 3 fetal). We have been able to demonstrate the co-localisation of these peptides in normal and neoplastic C-cells in all cases studied. Our results suggest that peptide sequences predicted by recombinant DNA technology can be localised using immunocytochemistry and that the combination of these techniques may have applications in diagnostic pathology.     

New evidence for,and challenges in,linking small CGG repeat expansion FMR1 alleles with Parkinson's disease

We recently reported a significant increase in the frequency of carriers of grey zone (GZ) alleles of FMR1 gene in Australian males with Parkinson's disease (PD) from Victoria and Tasmania. Here, we report data comparing an independent sample of 817 PD patients from Queensland to 1078 consecutive Australian male newborns from Victoria. We confirmed the earlier finding by observing a significant excess of GZ alleles in PD (4.8%) compared to controls (1.5%). Although both studies provided evidence in support of an association between GZ‐carrier status and increased risk for parkinsonism, the existing evidence in the literature from screening studies remains equivocal and we discuss the need for alternative approaches to resolve the issue.     

Limitations of polymerase chain reaction testing for diagnosing acute Epstein-Barr virus infections

Clinicians use molecular tests to detect Herpesviridae from blood without fully appreciating limitations of testing. Studies are needed to enhance our understanding of the impact of Herpesviridae latency on molecular testing. We retrospectively performed quantitative Epstein-Barr virus (EBV) on sera from patients between the ages of 1 and 30 who demonstrated serologic evidence of acute EBV (n = 50) or remote EBV (n = 50) infection. Epstein-Barr virus DNA was detected in 70% of acutely infected and 4% of remotely infected patients. Sera from acutely infected patients had higher EBV copy number than convalescent sera. Our results suggest that serology should be performed as the initial diagnostic test for acute EBV. The role for polymerase chain reaction in immunocompromised patients with impaired antibody responses or as a 2nd-line diagnostic test when serologic results are equivocal deserves further study.     

Hypercalcaemia in rheumatoid arthritis: investigation of its causes and implications.

When correction was made for hypoalbuminaemia, 23 of 50 ambulant patients with definite or classical rheumatoid arthritis were found to have hypercalcaemia. When these 23 patients were studied 6 months later, 7 had hypercalcaemia as defined by the correction factor for a low serum albumin level, and 6 of these patients had raised serum ionised calcium concentrations. Biochemical studies in the 23 patients indicated evidence of hyperparathyroidism, namely, hypophosphataemia, increased serum alkaline phosphatase, hyperchloraemia, and reduced tubular reabsorption of calcium. However, serum immunoreactive parathyroid hormone concentrations were normal. Only one patient had an abnormally low serum 25-hydroxy-vitamin D result: this patient had a high level of urinary D-glucaric acid and was receiving phenobarbitone for treatment of epilepsy. The biochemical features suggestive of parathyroid overactivity were particularly found in patients with raised serum calcium levels. The cause of hypercalcaemia in rheumatoid arthritis remains to be explained.