MOG encephalomyelitis: international recommendations on diagnosis and antibody testing

Over the past few years, new-generation cell-based assays have demonstrated a robust association of autoantibodies to full-length human myelin oligodendrocyte glycoprotein (MOG-IgG) with (mostly recurrent) optic neuritis, myelitis and brainstem encephalitis, as well as with acute disseminated encephalomyelitis (ADEM)-like presentations. Most experts now consider MOG-IgG-associated encephalomyelitis (MOG-EM) a disease entity in its own right, immunopathogenetically distinct from both classic multiple sclerosis (MS) and aquaporin-4 (AQP4)-IgG-positive neuromyelitis optica spectrum disorders (NMOSD). Owing to a substantial overlap in clinicoradiological presentation, MOG-EM was often unwittingly misdiagnosed as MS in the past. Accordingly, increasing numbers of patients with suspected or established MS are currently being tested for MOG-IgG. However, screening of large unselected cohorts for rare biomarkers can significantly reduce the positive predictive value of a test. To lessen the hazard of overdiagnosing MOG-EM, which may lead to inappropriate treatment, more selective criteria for MOG-IgG testing are urgently needed. In this paper, we propose indications for MOG-IgG testing based on expert consensus. In addition, we give a list of conditions atypical for MOG-EM ("red flags") that should prompt physicians to challenge a positive MOG-IgG test result. Finally, we provide recommendations regarding assay methodology, specimen sampling and data interpretation.

NMO-IgG predicts the outcome of recurrent optic neuritis

OBJECTIVE

To determine the prognostic value of neuromyelitis optica (NMO)-immunoglobulin G (IgG) in patients with recurrent optic neuritis (ON). The aquaporin-4-specific serum autoantibody, NMO-IgG, is a biomarker for NMO and relapsing transverse myelitis. Recurrent ON may herald multiple sclerosis (MS) or NMO, or it may occur as an isolated syndrome. The prognosis and response to therapy differs in each of these contexts.

METHODS

We evaluated 34 patients who were tested for NMO-IgG between 2000 and 2007 and who had two or more episodes of ON without satisfying a diagnosis of MS or NMO prior to serologic testing. Clinical data were available for 25 Mayo Clinic patients (5 NMO-IgG positive and 20 NMO-IgG negative) and for an additional 9 seropositive patients whose serum was referred to the Mayo Clinic Neuroimmunology laboratory for testing.

RESULTS

Twenty percent of the patients with recurrent ON seen at Mayo Clinic were seropositive. All NMO-IgG-positive patients (vs 65% NMO-IgG-negative patients) had at least one attack with visual acuity in the affected eye worse than 20/200 (p = 0.05). In seropositive patients for whom long-term follow-up was possible (median 8.9 years after the initial ON), 6 of 12 (50%) experienced an episode of myelitis and fulfilled criteria for NMO. In contrast, 1 of 15 seronegative patients (6.7%) fulfilled McDonald criteria for MS (p = 0.03). Seropositive patients had a final visual score which was worse than that of seronegative patients (p = 0.02).

CONCLUSIONS

Neuromyelitis optica (NMO)-immunoglobulin G seropositivity predicts poor visual outcome and development of NMO. Seropositive recurrent optic neuritis is a limited form of NMO.

Origin of the TEM-beta-lactamase gene found on plasmids

A sequence of deoxyribonucleic acid of 2.7 times 10-6 to 3.3 times 10-6 daltons which includes the TEM beta-lactamase gene is present on the small plasmid RSF 1030 (R-Amp). This same sequence is present on plasmid derivatives that have received a translocation of deoxyribonucleic acid specifying the TEM beta-lactamase and is also present on naturally occurring plasmids of the F1, F11, N, X, O, I, C, and W incompatibility groups that do not specify ampicillin resistance or specify O-type beta-lactamases.

Male infertility and environmental exposure to lead and cadmium

Humans are exposed occupationally and environmentally to metal aerosols including lead (Pb2+) and cadmium (Cd2+). These toxicants accumulate in male reproductive organs. Epidemiological studies have been equivocal about effects of Pb2+ and Cd2+ on hormone concentrations, male fertility and sperm parameters. Comparison of Pb2+ and Cd2+ concentrations in fertile and infertile men are problematic. Problem areas include failure to control confounding variables, but genetic polymorphisms as in somatic diseases may modulate Pb2+ and Cd2+ damage. Multiple calcium (Ca2+) and potassium (K+) channel isoforms have been identified in human testes and spermatozoa. These Ca2+ and K+ channels are involved in early events of acrosome reactions. Ca2+ channel are susceptible to Cd2+ poisoning and K+ channels to Pb2+. These channels offer entry paths for metallic toxicants into mature spermatozoa. Ion channel polymorphisms may cause differential sensitivities to Cd2+ and Pb2+, explaining in part prospective blinded studies showing high Cd2+ in varicocele-related human infertility and high Pb2+ in unexplained infertility. In both forms of male infertility the ability to undergo an acrosome reaction decreases. Reverse transcriptase-polymerase chain reaction assays for Ca2+ and K+ channel isoforms may identify susceptibility subgroups with lower resistance to environmental exposures.

Five year risk of progression of primary angle closure suspects to primary angle closure: a population based study

AIM

To report progression of primary angle closure suspects (PACS) to primary angle closure (PAC) at the 5 year follow up of a population based sample.

METHODS

82 of 118 PACS who could be contacted and 110 randomly selected normals from a population based survey in 1995 were invited for a follow up examination in 2000. Progression to PAC was based on the development of raised IOP or synechiae in a PACS.

RESULTS

50 of the 82 PACS contacted were examined. 11 (22%; 95% CI 9.8 to 34.2) developed PAC (seven synechial and four appositional); all were bilateral PACS. Two of 50 people previously diagnosed as PACS were reclassified as normal. One person among the 110 normals progressed to PAC. The relative risk of progression among PACS was 24 (95% CI 3.2 to 182.4). There was no significant difference in axial length, anterior chamber depth, or lens thickness between those who progressed and those who did not. None of the patients developed optic disc or field damage attributable to angle closure. One angle closure suspect was diagnosed to have normotensive glaucoma.

CONCLUSION

In this population based study of PACS the 5 year incidence of PAC was 22%; none developed functional damage. Bilateral PACS was a clinical risk factor for progression.

Brainstem manifestations in neuromyelitis optica: a multicenter study of 258 patients

BACKGROUND

Neuromyelitis optica (NMO) is a severe autoimmune disease of the central nervous system characterized by spinal cord and optic nerve involvement. Brainstem manifestations have recently been described.

OBJECTIVE

To evaluate the time of occurrence, the frequency and the characteristics of brainstem symptoms in a cohort of patients with NMO according to the ethnic background and the serologic status for anti-aquaporin-4 antibodies (AQP4-abs).

METHODS

We performed a multicenter study of 258 patients with NMO according to the 2006 Wingerchuk criteria and we evaluated prospectively the frequency, the date of onset and the duration of various brainstem signs in this population.

RESULTS

Brainstem signs were observed in 81 patients (31.4%). The most frequently observed signs were vomiting (33.1%), hiccups (22.3%), oculomotor dysfunction (19.8%), pruritus (12.4%), followed by hearing loss (2.5%), facial palsy (2.5%), vertigo or vestibular ataxia (1.7%), trigeminal neuralgia (2.5%) and other cranial nerve signs (3.3%). They were inaugural in 44 patients (54.3%). The prevalence was higher in the non-Caucasian population (36.6%) than in the Caucasian population (26%) (p<0.05) and was higher in AQP4-ab-seropositive patients (32.7%) than in seronegative patients (26%) (not significant).

CONCLUSIONS

This study confirms the high frequency of brainstem symptoms in NMO with a majority of vomiting and hiccups. The prevalence of these manifestations was higher in the non Caucasian population.

Characterization of neuromyelitis optica and neuromyelitis optica spectrum disorder patients with a late onset

BACKGROUND

Few data are available for patients with a late onset (≥ 50 years) of neuromyelitis optica (LONMO) or neuromyelitis optica spectrum disease (LONMOSD), defined by an optic neuritis/longitudinally extensive transverse myelitis with aquaporin-4 antibodies (AQP4-Ab).

OBJECTIVE

To characterize LONMO and LONMOSD, and to analyze their predictive factors of disability and death.

METHODS

We identified 430 patients from four cohorts of NMO/NMOSD in France, Germany, Turkey and UK. We extracted the late onset patients and analyzed them for predictive factors of disability and death, using the Cox proportional model.

RESULTS

We followed up on 63 patients with LONMO and 45 with LONMOSD during a mean of 4.6 years. This LONMO/LONMOSD cohort was mainly of Caucasian origin (93%), women (80%), seropositive for AQP4-Ab (85%) and from 50 to 82.5 years of age at onset. No progressive course was noted. At last follow-up, the median Expanded Disability Status Scale (EDSS) scores were 5.5 and 6 in the LONMO and LONMOSD groups, respectively. Outcome was mainly characterized by motor disability and relatively good visual function. At last follow-up, 14 patients had died, including seven (50%) due to acute myelitis and six (43%) because of opportunistic infections. The EDSS 4 score was independently predicted by an older age at onset, as a continuous variable after 50 years of age. Death was predicted by two independent factors: an older age at onset and a high annualized relapse rate.

CONCLUSION

LONMO/LONMOSD is particularly severe, with a high rate of motor impairment and death.

Enzymatic activity of the Src homology 2 domain-containing inositol phosphatase is regulated by a plasma membrane location

The negative regulatory role of the Src homology 2 domain-containing inositol 5-phosphatase (SHIP) has been invoked in a variety of receptor-mediated signaling pathways. In B lymphocytes, co-clustering of antigen receptor surface immunoglobulin with FcgammaRIIb promotes the negative effects of SHIP, but how SHIP activity is regulated is unknown. To explore this issue, we investigated the effect of SHIP phosphorylation, receptor tyrosine engagement by its Src homology 2 domain, and membrane recruitment of SHIP on its enzymatic activity. We examined two SHIP phosphorylation kinase candidates, Lyn and Syk, and observed that the Src protein-tyrosine kinase, Lyn is far superior to Syk in its ability to phosphorylate SHIP both in vitro and in vivo. However, we found a minimal effect of phosphorylation or receptor tyrosine engagement of SHIP on its enzymatic activity, whereas membrane localization of SHIP significantly reduced cellular phosphatidylinositol 3,4, 5-triphosphate levels. Based on our results, we propose that a membrane localization of SHIP is the crucial event in the induction of its phosphatase effects.

Multiple sclerosis risk in radiologically uncovered asymptomatic possible inflammatory-demyelinating disease

BACKGROUND

Natural history of patients with incidentally discovered lesions that fulfill magnetic resonance imaging (MRI) criteria for multiple sclerosis (MS) in the absence of objective clinical symptoms suggestive of central nervous system (CNS) inflammatory-demyelinating disease is not well defined.

OBJECTIVE

We evaluated the risk of developing symptomatic MS in patients with radiologically uncovered asymptomatic possible inflammatory-demyelinating disease (RAPIDD).

METHODS

We identified and longitudinally followed a cohort of 22 patients from two tertiary care MS centers: Istanbul University, Cerrahpasa School of Medicine, Istanbul, Turkey, and Mayo Clinic, Rochester, Minnesota, after an initial MRI study fulfilling the Barkhof-Tintore MRI criteria completed for other reasons unrelated to MS.

RESULTS

Eight of 22 patients developed an objective clinical symptom consistent with a CNS inflammatory-demyelinating syndrome and fulfilled dissemination in space and time criteria for definite MS. Median age at the time of diagnosis of MS was 44.8 years (range 28.3-71.4 years). Time taken for the development of definite MS was studied by survival analysis. Cumulative event rates were; 12 months: 9%, 24 months: 15%, 36 months: 30.4%, and 60 months: 44.6%. Six of 22 patients were followed beyond 60 months. Two of these six patients developed MS later (at 66 and 112 months, respectively). Three patients remained asymptomatic despite follow-up of 10 years.

CONCLUSIONS

PATIENTS

with RAPIDD develop MS at a similar rate to treated patients (and less frequently than placebo groups) with clinically isolated syndromes from prior randomized controlled studies. Some patients with RAPIDD continue to have radiological evolution of subclinical disease without MS symptoms despite long follow-up periods.

Contemporary management of acute coronary syndromes: does the practice match the evidence? The global registry of acute coronary events (GRACE)

OBJECTIVE

To determine to what extent evidence based guidelines are followed in the management of acute coronary syndromes (ACS) in the UK, elsewhere in Europe, and multinationally, and what the outcomes are.

DESIGN

Multinational, prospective, observational registry (GRACE, global registry of acute coronary events) with six months' follow up.

SETTING

Patients presenting to a cluster of hospitals. The study was designed to collect data representative of the full spectrum of ACS in specific geographic populations.

PATIENTS

Patients admitted with a working diagnosis of unstable angina or suspected myocardial infarction (MI).

MAIN OUTCOME MEASURES

Death during hospitalisation and at six months' follow up (adjusted for baseline risks).

RESULTS

In ST elevation MI, reperfusion was applied more often in the UK (71%) than in Europe (65%) and multinationally (59%) (p < 0.01). However, this was almost entirely by lytic treatment, in contrast with elsewhere (primary percutaneous coronary intervention 1%, 29%, 16%, respectively). Statins were applied more frequently in the UK for all classes of patients with ACS (p < 0.0001). In contrast there was lower use of revascularisation procedures in non-ST MI (20% v 37% v 28%, respectively) and glycoprotein IIb/IIIa antagonists (6% v 25% v 26%, respectively). In-hospital death rates, adjusted for baseline risk, were not significantly different but six month death rates were higher in the UK for ST elevation MI (7.2% UK, 4.3% Europe, 5.3% multinationally; p < 0.0001) and non-ST elevation MI (7.5%, 6.2%, and 6.7%, respectively; p = 0.012, UK v Europe).

CONCLUSIONS

Current management of ACS in the UK more closely follows the recommendations of the National Service Framework than British or European guidelines. Differences in practice may account for the observed higher event rates in the UK after hospital discharge.

FcgammaRIIb modulation of surface immunoglobulin-induced Akt activation in murine B cells

We examined activation of the serine/threonine kinase Akt in the murine B cell line A20. Akt is activated in a phosphoinositide 3-kinase (PtdIns 3-kinase)-dependent manner upon stimulation of the antigen receptor, surface immunoglobulin (sIg). In contrast, Akt induction is reduced upon co-clustering of sIg with the B cell IgG receptor, FcgammaRIIb. Co-clustering of sIg-FcgammaRIIb transmits a dominant negative signal and is associated with reduced accumulation of the PtdIns 3-kinase product phosphatidylinositol 3,4,5-trisphosphate (PtdIns 3,4,5-P3), known to be a potent activator of Akt. PtdIns 3-kinase is activated to the same extent with and without FcgammaRIIb co-ligation, indicating conditions supporting the generation of PtdIns 3,4,5-P3. We hypothesized that the decreased Akt activity arises from the consumption of PtdIns 3,4,5-P3 by the inositol-5-phosphatase Src homology 2-containing inositol 5-phosphatase (SHIP), which has been shown by us to be tyrosine-phosphorylated and associated with FcgammaRIIb when the latter is co-ligated. In direct support of this hypothesis, we report here that Akt induction is greatly reduced in fibroblasts expressing catalytically active but not inactive SHIP. Likewise, the reduction in Akt activity upon sIg-FcgammaRIIb co-clustering is absent from avian B cells lacking expression of SHIP. These findings indicate that SHIP acts as a negative regulator of Akt activation.

Hearing impairment and otitis media in a rural primary school in south India

In order to determine the prevalence of hearing impairment and otitis media in rural primary school children, a pilot study of 284 children aged 6-10 years was performed. These children were screened by otoscopy, pure tone audiometry and tympanometry. The overall prevalence of otological abnormalities (excluding wax) was 21.5%. Hearing impairment was detected in 34 children (11.9%). Conductive hearing impairment was predominant (10.9%). Otitis media was diagnosed in 17.6% of children. While 91.2% of children with hearing impairment had associated middle ear disease, only 53.4% of those with middle ear disease were detected as have hearing impairment. The importance of including tympanometry as part of the screening protocol is highlighted.

Recovery of spermatogenesis following bone marrow transplantation

Preparative regimens used in bone marrow transplantation usually result in impairment of male fertility. Although recovery of fertility is more likely after chemotherapy-based regimens, this is a rare occurrence after TBI containing regimens. We undertook a cross-sectional study of recovery of spermatogenesis in men who had undergone allogeneic and autologous marrow or peripheral stem cell transplant between 1984 and 1995. We identified six out of 42 patients eligible for analysis to have either recovered fertility or spermatogenesis. Seminal fluid analysis showed that four out of 25 patients recovered sperm counts. This has important implications for patient counselling, post-transplant follow-up and contraceptive advice.

Signal transduction by human-restricted Fc gamma RIIa involves three distinct cytoplasmic kinase families leading to phagocytosis

Recent experiments indicate an important role for Src family and Syk protein tyrosine kinases and phosphatidylinositol 3-kinase in the signal transduction process initiated by mouse receptors for IgG and leading to phagocytosis. Considerably less is known regarding signal transduction by the human-restricted IgG receptor, FcgammaRIIa. Furthermore, the relationship among the Src family, Syk, and phosphatidylinositol 3-kinase in phagocytosis is not understood. Here, we show that FcgammaRIIa is phosphorylated by an Src family member, which results in recruitment and concomitant activation of the distal enzymes Syk and phosphatidylinositol 3-kinase. Using a FcgammaRI-p85 receptor chimera cotransfected with kinase-inactive mutants of Syk or application of a pharmacological inhibitor of Syk, we show that Syk acts in parallel with phosphatidylinositol 3-kinase. Our results indicate that FcgammaRIIa-initiated monocyte or neutrophil phagocytosis proceeds from the clustered IgG receptor to Src to phosphatidylinositol 3-kinase and Syk.

Assessment of increasing loading rate on two-stage digestion of food waste

A two-stage food waste digestion system involved a first stage hydrolysis reactor followed by a second stage methanogenic reactor. Organic loading rates (OLR) were increased from 6 to 15 g VS L(-1) d(-1) in the hydrolysis reactor and from 2 to 5 g VS L(-1) d(-1) in the methanogenic reactor. The retention time was fixed at 4 days (hydrolysis reactor) and 12 days (methane reactor). A single-stage digester was subjected to similar loading rates as the methanogenic reactor at 16 days retention. Increased OLR resulted in higher quantities of liquid fermentation products from the first stage hydrolysis reactor. Solubilisation of chemical oxygen demand peaked at 47% at the maximum loading. However, enhanced hydrolysis yields had no significant impact on the specific methane yields. The two-stage system increased methane yields up to 23% and enriched methane content by an average of 14% to levels of 71%.

Analysis of ligase chain reaction products via matrix-assisted laser desorption/ionization time-of-flight-mass spectrometry

A rapid and accurate detection of ligation products generated in ligase chain reactions (LCR) by using matrix-assisted laser desorption/ionization time-of-flight-mass spectrometry (MALDI-TOF-MS) is reported. LCR with Pfu DNA ligase was performed with a wild-type template and a template carrying a single point mutation within the Escherichia coli lacI gene as a model system. Starting from about 1 fmol of template DNA the ligation product generated in the positive reactions was analyzed with HPLC and MALDI-TOF-MS, whereby the need of proper sample purification prior to mass spectrometric analysis was demonstrated. A purification procedure with a high potential for automation using streptavidin-coated magnetic particles and ultrafiltration was introduced. Plasmid DNA and short single-stranded oligonucleotides have been used as template. A point mutation could be discriminated from the wild-type template due to the absence or presence of ligation product. This approach allows the rapid-specific detection of template DNA in femtomole amounts and moreover can distinguish between sequence variations in DNA molecules down to point mutations without the need for labeling, gel electrophoresis, membrane transfer, or hybridization procedures.

Chronic bacterial rhinosinusitis: description of a mouse model

OBJECTIVES

To survey normal murine sinonasal anatomy and to create a mouse model for chronic bacterial rhinosinusitis.

DESIGN

Anatomic, histologic, and pathophysiologic study displaying normal murine sinonasal anatomy and surgically created unilateral sinonasal inflammation.

SUBJECTS

Twenty-one 6-week-old, male C57BL/6 mice.

INTERVENTIONS

Animals that underwent unilateral maxillary sinus ostial obstruction using Merocel nasal packing, animals with unilateral Bacteroides fragilis inoculation alone, and animals with both ostial obstruction and bacterial inoculation were examined at 4 weeks for histologic evidence of chronic sinonasal inflammation. Experimental interventions were compared with contralateral control sinuses within each animal and with normal and sham-operated controls.

RESULTS

Normal mouse paranasal sinuses include maxillary sinuses, ethmoid air cells, and respiratory-type epithelium. In experimental animals, the lateral maxillary sinus wall, nasal septum, and superior turbinelle of the maxillary sinus were examined histologically. Epithelial thickening and disarray, goblet cell hyperplasia, inflammatory infiltrates, and sinonasal fibrosis were present in the experimental sinuses of animals packed with Merocel alone or Merocel with bacterial inoculation. Changes seen with Merocel and bacteria were more dramatic than those with Merocel alone. Sham-operated controls and sinuses inoculated with bacteria alone did not differ significantly from the sinuses of normal animals.

CONCLUSION

Unilateral maxillary sinus ostial obstruction using Merocel nasal packing along with B fragilis inoculation results in a persistent, localized bacterial rhinosinusitis in mice.

Secondary antibody deficiency: a complication of anti-CD20 therapy for neuroinflammation

B-cell depleting anti-CD20 monoclonal antibody therapies are being increasingly used as long-term maintenance therapy for neuroinflammatory disease compared to many non-neurological diseases where they are used as remission-inducing agents. While hypogammaglobulinaemia is known to occur in over half of patients treated with medium to long-term B-cell-depleting therapy (in our cohort IgG 38, IgM 56 and IgA 18%), the risk of infections it poses seems to be under-recognised. Here, we report five cases of serious infections associated with hypogammaglobulinaemia occurring in patients receiving rituximab for neuromyelitis optica spectrum disorders. Sixty-four per cent of the whole cohort of patients studied had hypogammaglobulinemia. We discuss the implications of these cases to the wider use of anti-CD20 therapy in neuroinflammatory disease.

Human papillomavirus infection in "young" versus "old" patients with squamous cell carcinoma of the head and neck

BACKGROUND

Human papillomavirus (HPV) represents a potential risk factor for squamous cell cancer of the head and neck (SCCHN). We evaluated the prevalence of HPV DNA in patients with SCCHN diagnosed at the University of Michigan from 1994-1996.

METHODS

Patients were stratified by age at diagnosis as "young" (<50 years; median, 39) or "old" (>50 years; median, 66). Fourteen "young" and 14 "old" were matched for tumor site, and 4 additional "old" patients were included. Specimens were analyzed by polymerase chain reaction for HPV DNA using 2 sets of consensus primers. HPV sequences were confirmed by Southern blot hybridization and typed with type-specific probes.

RESULTS

Overall, 15 of 32 (46.9%) samples contained HPV sequences. HPV 16 was detected in 9 of 15 (60%), HPV-18 in 1 of 15 (6.6%), and 5 of 15 (33.3%) remained untyped by multiple methods. When stratified, 7 of 14 (50%) "young" were HPV-positive compared with 8 of 18 (44.4%) "old" (p =.76). Survival in patients with HPV-positive SCCHN was significantly longer than that for HPV-negative patients.

CONCLUSIONS

The incidence of HPV in "young" versus "old" is not significantly different, suggesting similar roles for both groups. Patients with HPV-positive tumors may have a survival advantage relative to patients with HPV-negative tumors.

Chronic suppurative otitis media: prevalence and practices among rural South Indian children

In order to determine the prevalence of chronic suppurative otitis media (CSOM) in rural South Indian children, a cross-sectional survey was conducted among 914 children (484 boys and 430 girls) from four primary schools and 12 nurseries (balwadis; preschool), of adjacent villages of North Arcot District of Tamil Nadu state. The preschool children were aged 2-5 years, while the ages of the primary school children ranged from 6 to 10 years. The overall prevalence rate of CSOM was found to be 6%. The disease was equally prevalent in preschool children (5.7%) and primary school children (6.2%) (P = 0.94). Cholesteatomatous ear disease was observed in 1.2% of children, those of the older age group having a slightly higher prevalence rate (1.5%) than the younger age group (0.7%). Parental beliefs and existing practices with respect to the disease are also presented.

Recovery of nucleic acids from immobilized biotin-streptavidin complexes using ammonium hydroxide and applications in MALDI-TOF mass spectrometry

The effects of ammonium hydroxide treatment of complexes consisting of biotinylated nucleic acids and immobilized streptavidin were investigated. It was found that incubation of such complexes with ammonium hydroxide at room temperature leads to denaturation of double-stranded DNA molecules, liberating only the complementary nonbiotinylated strand, whereas incubation at elevated temperatures leads to an efficient dissociation of biotin-streptavidin complexes. The introduced procedure is especially suitable as a purification and conditioning format prior to matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometric analysis of DNA from complex enzymatic reactions. This is demonstrated by analysis of polymerase chain reaction (PCR) and sequencing products.

Imaging abnormalities in sporadic hemiplegic migraine on conventional MRI, diffusion and perfusion MRI and MRS

Prolonged hemiparetic migraine aura can cause diagnostic confusion and be mistaken for ischaemic stroke occurring during the course of a migraine--'migrainous infarction'. We report a case of prolonged hemiparesis occurring during the course of a migraine attack. Though initially confused with migrainous infarction, we suggest with sequential magnetic resonance imaging, magnetic resonance angiography, diffusion, perfusion images and magnetic resonance spectroscopy that the hemiplegia was not of vascular origin and that the patient had sporadic hemiplegic migraine. We hypothesize that the mechanisms of sporadic hemiplegic migraine probably lie at a cellular level, similiar to familial hemiplegic migraine.

Dietary intake of choline and plasma choline concentrations in pregnant women in Jamaica

Choline is an essential nutrient for humans and its availability during pregnancy is important for optimal fetal development. The Food and Nutrition Board of the Institute of Medicine in the United States of America has set the adequate choline intake during pregnancy at 450 mg/day. There is limited data available on normal plasma choline concentrations in pregnancy. Moreover, there are neither documented studies of choline intake among pregnant women in the Jamaican population nor of free plasma choline concentrations during pregnancy. Sixteen women presenting to the antenatal clinic of the University Hospital of the West Indies (UHWI) at 10-15 weeks of gestation were selected for this pilot study. A food frequency questionnaire was administered to estimate frequency of consumption of foods rich in choline. Fasting blood samples were collected by venepuncture and plasma assayed for choline using liquid chromatography electrospray ionization isotopic dilution mass spectrometry. Most of the women reported consumption of diets that delivered less than the recommended choline intake (mean +/- SEM, 278.5 +/- 28.9 mg). Mean plasma choline concentration was 8.4 +/- 0.4 micromol/L. This falls below the normal concentration (10 micromol/L) reported for individuals that are not pregnant and pregnant (14.5 micromol/L). The results of this study may be an indication that the choline included in the diet of pregnant women in Jamaica may not be adequate to meet both the needs of the mother and fetus and that further studies are warranted to determine clinical implications.