Association between Gc genotype and susceptibility to TB is dependent on vitamin D status

Group-specific component (Gc) variants of vitamin D binding protein differ in their affinity for vitamin D metabolites that modulate antimycobacterial immunity. We conducted studies to determine whether Gc genotype associates with susceptibility to tuberculosis (TB). The following subjects were recruited into case-control studies: in the UK, 123 adult TB patients and 140 controls, all of Gujarati Asian ethnic origin; in Brazil, 130 adult TB patients and 78 controls; and in South Africa, 281 children with TB and 182 controls. Gc genotypes were determined and their frequency was compared between cases versus controls. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were obtained retrospectively for 139 Gujarati Asians, and case-control analysis was stratified by vitamin D status. Interferon (IFN)-gamma release assays were also performed on 36 Gujarati Asian TB contacts. The Gc2/2 genotype was strongly associated with susceptibility to active TB in Gujarati Asians, compared with Gc1/1 genotype (OR 2.81, 95% CI 1.19-6.66; p = 0.009). This association was preserved if serum 25(OH)D was <20 nmol.L(-1) (p = 0.01) but not if serum 25(OH)D was > or =20 nmol.L(-1) (p = 0.36). Carriage of the Gc2 allele was associated with increased PPD of tuberculin-stimulated IFN-gamma release in Gujarati Asian TB contacts (p = 0.02). No association between Gc genotype and susceptibility to TB was observed in other ethnic groups studied.

Nerve blocks in the treatment of headache

Nerve blocks and neurostimulation are reasonable therapeutic options in patients with head and neck neuralgias. In addition, these peripheral nerve procedures can also be effective in primary headache disorders, such as migraine and cluster headaches. Nerve blocks for headaches are generally accomplished by using small subcutaneous injections of amide-type local anesthetics, such as lidocaine and bupivicaine. Targets include the greater occipital nerve, lesser occipital nerve, auriculotemporal nerve, supratrochlear and supraorbital nerves, sphenopalatine ganglion, cervical spinal roots, and facet joints of the upper cervical spine. Although definitive studies examining the usefulness of nerve blocks are lacking, reports suggest that this area deserves further attention in the hope of acquiring evidence of effectiveness.

Tail regeneration in Xenopus laevis as a model for understanding tissue repair

Augmentation of regenerative ability is a powerful strategy being pursued for the biomedical management of traumatic injury, cancer, and degeneration. While considerable attention has been focused on embryonic stem cells, it is clear that much remains to be learned about how somatic cells may be controlled in the adult organism. The tadpole of the frog Xenopus laevis is a powerful model system within which fundamental mechanisms of regeneration are being addressed. The tadpole tail contains spinal cord, muscle, vasculature, and other terminally differentiated cell types and can fully regenerate itself through tissue renewal--a process that is most relevant to mammalian healing. Recent insight into this process has uncovered fascinating molecular details of how a complex appendage senses injury and rapidly repairs the necessary morphology. Here, we review what is known about the chemical and bioelectric signals underlying this process and draw analogies to evolutionarily conserved pathways in other patterning systems. The understanding of this process is not only of fundamental interest for the evolutionary and cell biology of morphogenesis, but will also generate information that is crucial to the development of regenerative therapies for human tissues and organs.

Peliosis hepatis following treatment with androgen-steroids in patients with bone marrow failure syndromes

Androgens widely used in the treatment of bone marrow failure syndromes can in rare cases cause hepatic peliosis, a pathological entity characterized by multiple blood-filled cavities in the liver parenchyma. Bone marrow failure syndromes per se are associated with a low coagulation status, which is further magnified by bone marrow transplantation for aplastic anaemia due to deep thrombocytopenia. Both these conditions can cause bleeding; their combination is especially dangerous. We describe two cases of aplastic anaemia due to paroxysmal nocturnal hemoglobinuria and Fanconi syndrome, in which patients developed peliosis hepatis after prolonged treatment with androgens. One patient developed severe subcapsular bleeding, successfully treated with catheterization of the right hepatic artery and embolization of the bleeding site. The second patient bridged over deep post-transplant aplasia with high frequency platelet transfusions, and demonstrated an uncomplicated post-BMT course. We suggest avoiding or interrupting treatment with androgens in patients preparing for BMT.

An analysis of cluster headache information provided on internet websites

OBJECTIVE

To evaluate the quality of websites providing cluster headache information for patients and healthcare providers.

BACKGROUND

The Internet has become an increasingly important source of healthcare information. However, limited data exist regarding the quality of websites providing headache information.

METHODS

This was a cross-sectional study conducted in February 2007. Websites providing cluster headache information were determined on the search engine MetaCrawler and classified as either patient oriented or healthcare provider oriented. The overall quality of each site was evaluated using a score system. Readability was evaluated using the Flesch-Kincaid Grade Level Readability Score (FKRS). Website quality was analyzed based on ownership, purpose, authorship, author qualifications, attribution, interactivity, and currency. The technical quality of the cluster headache information was analyzed based on content specific to cluster headache. The final ranking, based on the sum of the ranks of all 3 categories, was determined and then contrasted between the patient-oriented and healthcare professional-oriented websites using 2-sample t-tests.

RESULTS

Of the first 40 websites found on MetaCrawler, 72.5% were advertisements, unrelated to headache, or repeated websites. Although the standard US writing averages are at a seventh to eighth grade level, the mean FKRS of all sites was at a 12th grade level of difficulty, with no significant difference between the patient-oriented or healthcare provider-oriented websites (P = .54). Of a total possible 14 points, the overall mean quality component score was 9.9 for all sites; and of a total possible 23 points, the overall mean technical component score was 13.9. There was no significant difference for either the quality or technical component scores between patient-oriented or healthcare provider-oriented websites (P = .45 and P = .80, respectively).

CONCLUSION

There are numerous cluster headache websites that can be found on the Internet. The quality of most of the websites dedicated to cluster headache is mediocre, and although there are some excellent cluster headache websites, these sites may be challenging for many users to locate. There was no significant difference in the overall quality of websites oriented for patients or healthcare providers providing cluster headache information evaluated in this study. In addition, websites providing high-quality cluster headache information are written at an educational level too high for a significant portion of the general population to fully utilize. Physicians should strongly consider providing lists of quality websites on cluster headache for their patients.

Haplotypic diversity in human CEACAM genes: effects on susceptibility to meningococcal disease

Adhesion between the opacity-associated adhesin (Opa) proteins of Neisseria meningitidis and human carcino-embryonic antigen cell adhesion molecule (CEACAM) proteins is an important stage in the pathogenesis of meningococcal disease, a globally important bacterial infection. Most disease is caused by a small number of meningococcal genotypes known as hyperinvasive lineages. As these are also carried asymptomatically, acquisition of them alone cannot explain why only some hosts develop meningococcal disease. Our aim was to determine whether genetic diversity in CEACAM is associated with susceptibility to meningococcal disease. Frequency distributions of alleles, genotypes and haplotypes were compared in four CEACAM genes in 384 case samples and 190 controls. Linkage disequilibrium among polymorphic sites, haplotype structures and relationships were also analysed. A number of polymorphisms were observed in CEACAM genes but the diversity of CEACAM1, to which most Opa proteins bind, was lower, and a small number of high-frequency haplotypes were detected. Dose-dependent associations of three CEACAM haplotypes with meningococcal disease were observed, with the effect of carrying these haplotypes amplified in homozygous individuals. Two haplotypes were protective while one haplotype in CEACAM6 was associated with a twofold increase in disease susceptibility. These data imply that human CEACAM may be one determinant of human susceptibility to meningococcal disease.

Greater occipital nerve block for migraine and other headaches: Is it useful?

Peripheral nerve blocks have long been used in headache treatment. The most widely used procedure for this purpose has been greater occipital nerve (GON) block. The rationale for using GON block in headache treatment comes from evidence for convergence of sensory input to trigeminal nucleus caudalis neurons from both cervical and trigeminal fibers. Although there is no standardized procedure for GON blockade, the nerve is usually infiltrated with a local anesthetic (lidocaine, bupivacaine, or both). A corticosteroid is sometimes added. Several studies suggested efficacy of GON block in the treatment of migraine, cluster headache, and chronic daily headache. However, few were controlled and blinded. Despite a favorable clinical experience, little evidence exists for the efficacy of GON block in migraine treatment. Controlled studies are needed to better assess the role of GON block in the treatment of migraine and other headaches.