Neurologic aspects of inflammatory bowel disease

To determine the frequency, spectrum, and clinical features of neurologic disorders associated with ulcerative colitis (UC) and Crohn's disease (CD).

BACKGROUND

Extraintestinal manifestations of inflammatory bowel disease (IBD) are well documented, but the association of IBD with neurologic involvement is rare and often controversial.

METHODS

Tertiary care center ambulatory and hospital services data bank retrospective computerized search with subsequent file review.

PATIENTS

From among 638 IBD patients diagnosed from 1981 to 1991, we identified 10 CD patients and nine UC patients with neurologic involvement unrelated to a defined systemic or iatrogenic cause. Neurologic disorders diagnosed 15 or more years before the intestinal symptomatology were excluded.

RESULTS

Three percent of IBD patients had neurologic involvement. In 14 of 19 (74%), it started within a mean of 5.7 years (range, 0.7 to 12 years) after the diagnosis of bowel disease, and in two of 19 (10%) it occurred at the time of IBD exacerbation. During the course of IBD, 10 of 19 patients (53%) exhibited other extraintestinal manifestations. Peripheral nerve disorders were observed in six UC patients. Myelopathy (5 patients), myopathy (3), and myasthenia gravis (1) were diagnosed in eight CD patients and one UC patient. Cerebrovascular disorders occurred in two UC and two CD patients.

CONCLUSIONS

Neurologic disorders associated with IBD are more common than appreciated and follow a different pattern of involvement in UC and CD. A prospective study is required to define the nature of this association.

Herpes simplex virus type 1 latency-associated transcripts are evidently not essential for latent infection

The herpes simplex virus type 1 (HSV-1) transcripts that can be detected during latent infection by Northern blot analysis in human and experimental animal sensory ganglia are encoded by diploid genes. To investigate their role in latent infection we studied HSV-1 variant 1704, which has deleted most of the IRL copy of the coding region of these RNAs and has a 1.2-kb deletion that is immediately upstream of the coding region of the TRL copy. During primary infection, 1704 replicated in trigeminal ganglia with kinetics similar to the parent virus (17+) and established latent infection. However, while explant reactivation of latent HSV-1 from trigeminal ganglia was detected in 100% of 17+ infected mice within 7 days, the reactivation of 1704 was significantly delayed, and 31 days elapsed before eight out of nine mice became virus positive. The recognized HSV-1 latency-associated RNAs were not detected during the latent state of 1704 by Northern blot analysis or in situ hybridization, which implies that the 1.2-kb deletion may contain the promoter or other important regulatory elements. The data indicate that detectable levels of these latency-associated transcripts are not required for viral replication, establishment, or maintenance (greater than 6 weeks) of HSV-1 latency in trigeminal ganglia, but suggest a role in reactivation.

Viral meningoencephalitis: a review of diagnostic methods and guidelines for management

BACKGROUND

Viral encephalitis is a medical emergency. The prognosis depends mainly on the pathogen and host immunologic state. Correct immediate diagnosis and introduction of symptomatic and specific therapy has a dramatic influence upon survival and reduces the extent of permanent brain injury.

METHODS

We searched the literature from 1966 to 2009. Recommendations were reached by consensus. Where there was lack of evidence but consensus was clear, we have stated our opinion as good practice points.

RECOMMENDATIONS

Diagnosis should be based on medical history and examination followed by CSF analysis for protein and glucose levels, cellular analysis, and identification of the pathogen by polymerase chain reaction amplification (recommendation level A) and serology (level B). Neuroimaging, preferably by MRI, is essential (level B). Lumbar puncture can follow neuroimaging when immediately available, but if this cannot be performed immediately, LP should be delayed only under unusual circumstances. Brain biopsy should be reserved only for unusual and diagnostically difficult cases. Patients must be hospitalized with easy access to intensive care units. Specific, evidence-based, antiviral therapy, acyclovir, is available for herpes encephalitis (level A) and may also be effective for varicella-zoster virus encephalitis. Ganciclovir and foscarnet can be given to treat cytomegalovirus encephalitis, and pleconaril for enterovirus encephalitis (IV class evidence). Corticosteroids as an adjunct treatment for acute viral encephalitis are not generally considered to be effective, and their use is controversial, but this important issue is currently being evaluated in a large clinical trial. Surgical decompression is indicated for impending uncal herniation or increased intracranial pressure refractory to medical management.

EFNS guideline on the management of community-acquired bacterial meningitis: report of an EFNS Task Force on acute bacterial meningitis in older children and adults

Acute bacterial meningitis (ABM) is a potentially life-threatening neurological emergency. An agreed protocol for early, evidence-based and effective management of community-acquired ABM is essential for best possible outcome. A literature search of peer-reviewed articles on ABM was used to collect data on the management of ABM in older children and adults. Based on the strength of published evidence, a consensus guideline was developed for initial management, investigations, antibiotics and supportive therapy of community-acquired ABM. Patients with ABM should be rapidly hospitalized and assessed for consideration of lumbar puncture (LP) if clinically safe. Ideally, patients should have fast-track brain imaging before LP, but initiation of antibiotic therapy should not be delayed beyond 3 h after first contact of patient with health service. In every case, blood sample must be sent for culture before initiating antibiotic therapy. Laboratory examination of cerebrospinal fluid is the most definitive investigation for ABM and whenever possible, the choice of antibiotics, and the duration of therapy, should be guided by the microbiological diagnosis. Parenteral therapy with a third-generation cephalosporin is the initial antibiotics of choice in the absence of penicillin allergy and bacterial resistance; amoxicillin should be used in addition if meningitis because of Listeria monocytogenes is suspected. Vancomycin is the preferred antibiotic for penicillin-resistant pneumococcal meningitis. Dexamethasone should be administered both in adults and in children with or shortly before the first dose of antibiotic in suspected cases of Streptococcus pneumoniae and H. Influenzae meningitis. In patients presenting with rapidly evolving petechial skin rash, antibiotic therapy must be initiated immediately on suspicion of Neisseria meningitidis infection with parenteral benzyl penicillin in the absence of known history of penicillin allergy.

Viral encephalitis: a review of diagnostic methods and guidelines for management

Viral encephalitis is a medical emergency. The spectrum of brain involvement and the prognosis are dependent mainly on the specific pathogen and the immunological state of the host. Although specific therapy is limited to only several viral agents, correct immediate diagnosis and introduction of symptomatic and specific therapy has a dramatic influence upon survival and reduces the extent of permanent brain injury in survivors. We searched MEDLINE (National Library of Medicine) for relevant literature from 1966 to May 2004. Review articles and book chapters were also included. Recommendations are based on this literature based on our judgment of the relevance of the references to the subject. Recommendations were reached by consensus. Where there was lack of evidence but consensus was clear we have stated our opinion as good practice points. Diagnosis should be based on medical history, examination followed by analysis of cerebrospinal fluid for protein and glucose contents, cellular analysis and identification of the pathogen by polymerase chain reaction (PCR) amplification (recommendation level A) and serology (recommendation level B). Neuroimaging, preferably by magnetic resonance imaging, is an essential aspect of evaluation (recommendation level B). Lumbar puncture can follow neuroimaging when immediately available, but if this cannot be obtained at the shortest span of time it should be delayed only in the presence of strict contraindications. Brain biopsy should be reserved only for unusual and diagnostically difficult cases. All encephalitis cases must be hospitalized with an access to intensive care units. Supportive therapy is an important basis of management. Specific, evidence-based, anti-viral therapy, acyclovir, is available for herpes encephalitis (recommendation level A). Acyclovir might also be effective for varicella-zoster virus encephalitis, gancyclovir and foscarnet for cytomegalovirus encephalitis and pleconaril for enterovirus encephalitis (IV class of evidence). Corticosteroids as an adjunct treatment for acute viral encephalitis are not generally considered to be effective and their use is controversial. Surgical decompression is indicated for impending uncal herniation or increased intracranial pressure refractory to medical management.

A herpes simplex virus type 1 mutant containing a nontransinducing Vmw65 protein establishes latent infection in vivo in the absence of viral replication and reactivates efficiently from explanted trigeminal ganglia

Vmw65, a herpes simplex virus type 1 (HSV-1) tegument protein, in association with cellular proteins, transactivates viral immediate early genes. In order to examine the role of Vmw65 during acute and latent infection in vivo, a mutant virus (in1814), containing a 12-base-pair insertion in the Vmw65 gene, which lacks the transactivating function of Vmw65 (C. I. Ace, T. A. McKee, J. M. Ryan, J. M. Cameron, and C. M. Preston, J. Virol. 63:2260-2269, 1989) was examined in mice. Following corneal inoculation, the parental virus (17+) and the revertant (1814R) replicated effectively in eyes and trigeminal ganglia with 30 to 60% mortality. At either equal PFU or equal particle numbers, in1814 did not replicate in trigeminal ganglia and none of the infected mice died. Although in1814 did not replicate following corneal inoculation, it established latent infection in trigeminal ganglia. HSV-1 in1814 reactivated at explant as efficiently and rapidly as did 17+ and 1814R. Even low amounts of inoculated in1814 (10(2) PFU) were sufficient to establish latent infection in some animals. Since infectious in1814 was not detected at any time in mouse trigeminal ganglia, in1814 provided a unique opportunity to determine how soon after primary infection latency begins. Latent in1814 infection was detected shortly after virus reached the sensory ganglia, between 24 to 48 h postinfection. Thus, though Vmw65 may be required for lytic infection in vivo, it is dispensable for the establishment of and reactivation from latent infection. These data support the hypotheses that the latent and lytic pathways of HSV-1 are distinct and that latency is established soon after infection without a requirement for viral replication. However, the levels of Vmw65 reaching neuronal nuclei may be a critical determinant of whether HSV-1 forms a lytic or latent infection.

In vivo and in vitro reactivation impairment of a herpes simplex virus type 1 latency-associated transcript variant in a rabbit eye model

Many recent studies of latent herpes simplex virus type 1 (HSV-1) infections within the nervous system have focused on the diploid genes encoding the latency-associated transcripts (LATs). The impaired explant reactivation of LAT variants from mouse trigeminal ganglia has implicated the LATs in the efficiency or speed of the reactivation process (D. A. Leib, C. L. Bogard, M. Kosz-Vnenchak, K. A. Hicks, D. M. Coen, D. M. Knipe, and P. A. Schaffer, J. Virol. 63:2893-2900, 1989; I. Steiner, J. G. Spivack, R. P. Lirette, S. M. Brown, A. R. MacLean, J. H. Subak-Sharpe, and N. W. Fraser, EMBO J. 8:505-511, 1989). However, it is not known how closely explant reactivation mimics the reactivation process in vivo. In the current study, a LAT variant (1704), parental strain (17+), and rescuant (1704R) were compared in vivo for reactivation of latent infection by iontophoresis in the rabbit eye model and in vitro by explant cocultivation of trigeminal ganglia from rabbits. Following iontophoresis, 17+ and 1704R reactivated in vivo from 76 and 64% of rabbits, respectively, while 1704 reactivated only from 4% (1 of 25) of the animals. In explant reactivation experiments, 17+ and 1704R reactivated from 98 and 67% of rabbit trigeminal ganglia, while 1704 reactivated from only 28% of trigeminal ganglia. The mean time required for the appearance of reactivated 1704 in explant culture, 17 days, was significantly longer than for 17+ and 1704R, 8 to 9 days. Thus, the explant reactivation kinetics in rabbit trigeminal ganglia reflect the behavior of LAT variant 1704 in vivo in the rabbit eye model. These data support the role of the LATs in the reactivation process and support the hypothesis that explant reactivation is a suitable system for analyzing the biological behavior of HSV-1 variants with defined genetic alterations in the LAT gene.

Neurologic manifestations of progressive systemic sclerosis

Neurologic involvement in progressive systemic sclerosis is considered uncommon. We retrospectively examined the prevalence and nature of neurologic complications in 50 patients with progressive systemic sclerosis. In 20 (40%), neurologic abnormalities were detected, with a total of 28 neurologic manifestations. All levels of the central and peripheral nervous system were affected: muscle (22%), peripheral nerve (18%), spinal cord (8%), and brain (6%). Of note were the presence of myelopathy in four patients and inclusion-body myositis in two. In 10 patients (20%), no definable cause of the neurologic dysfunction could be identified, apart from progressive systemic sclerosis. Thus, neurologic presentations of progressive systemic sclerosis are much more common than previously reported and may be due to direct involvement of the nervous system by a primary pathologic process in a significant number of patients.

A GPS logger and software for analysis of homing in pigeons and small mammals

A detailed analysis of homing in pigeons and small mammals has remained difficult because the paths of the animals could not be reconstructed precisely. Here, we describe a lightweight global position system (GPS) data logger (35 g including battery and casing; 40 x 68 x 18 mm) that records the flight of pigeons and the path of dogs with an accuracy of +/-12 m. With one battery, the logger runs in continuous mode (1 fix/s) for 3.5 h and in power-saving mode (1 fix/5 s) for about 16 h, and stores a maximum of 100,000 data points that are downloaded to a PC. A module of our public domain software WINTRACK permits a detailed numerical and graphical analysis of path geometry, phases of resting and moving, and path similarity. The device can be adapted to different species provided that satellite signals can be received reliably and that the loggers can be recovered. We expect it to be useful for testing hypotheses about pigeon homing, assessing natural spatial behavior and orientation of many species, and anticipate further miniaturization.

The value of cerebrospinal fluid antiviral antibody in the diagnosis of neurologic disease produced by varicella zoster virus

We studied four patients with subacute to chronic varicella zoster virus (VZV) infection of the central nervous system (CNS). VZV infection was verified by detecting antibody to VZV in the cerebrospinal fluid (CSF). VZV caused myelitis in two patients and encephalitis in two patients. In one of the patients with VZV encephalitis, in addition to VZV IgM antibody, VZV DNA was found in the CSF. Among the four patients with VZV infection of the CNS, CSF antibody to VZV was the crucial diagnostic laboratory test which corroborated the clinical features, and indicated that VZV caused neurologic disease. In addition to looking for amplifiable VZV DNA in the CSF of patients with neurologic disease whose clinical and radiologic features suggest VZV infection, we also recommend a search for CSF antibody to VZV, particularly in patients with intervals of weeks to months between zoster and the onset of neurologic disease, or in those patients without rash in whom the tempo of illness is unknown.

Herpes simplex virus type 1 latency-associated transcripts suppress viral replication and reduce immediate-early gene mRNA levels in a neuronal cell line

During herpes simplex virus type 1 (HSV-1) latent infection in human dorsal root ganglia, limited viral transcription, which has been linked to HSV-1 reactivation ability, takes place. To study the involvement of this transcription in HSV-1 replication in neuronal cells and consequently in viral latency, we constructed stably transfected neuronal cell lines containing (i) the entire HSV-1 latency transcriptionally active DNA fragment, (ii) the same DNA sequence with deletions of the latency-associated transcript (LAT) promoters, or (iii) the DNA coding sequence of the LAT domain. Replication of HSV-1 or a LAT-negative mutant was markedly repressed in the LAT-expressing cells, a phenomenon mediated by the LATs. To study the mechanism responsible for this effect, we examined LAT influence upon expression of HSV-1 immediate-early (IE) genes ICP0, ICP4, and ICP27, by Northern blot analysis. Following infection of a LAT-expressing neuronal cell line with a LAT-negative mutant, the steady-state levels of all three IE mRNAs were reduced compared to those for control cells. Transient transfections into a neuronal cell line indicated that the LAT suppressive effect upon ICP0 mRNA was mediated directly and was not due to the LAT effect upon the ICP0 promoter. We therefore propose that the LATs may repress viral replication in neuronal cells by reducing IE gene mRNA levels and thus facilitate the establishment of HSV-1 latency in nervous tissue.

Latent herpes simplex virus type 1 transcription in human trigeminal ganglia

We studied latent herpes simplex virus type 1 gene expression in human trigeminal ganglia. Two transcripts were mapped to a 3.0-kilobase region within the long repeat region and appeared to be located in neuronal nuclei. These viral RNAs were not abundant during lytic replication and may represent an alternative pattern of herpes simplex virus type 1 gene expression involved in the pathogenesis of latent infection.

A herpes simplex virus type 1 latency-associated transcript mutant reactivates with normal kinetics from latent infection

The herpes simplex virus type 1 (HSV-1) latency-associated transcripts (LATs) accumulate in neuronal nuclei of latently infected ganglia. Explant reactivation kinetics of LAT deletion mutants in the mouse eye model have suggested a role for the LATs in the reactivation process. This report describes the construction and characterization of an HSV-1 strain HFEM mutant, TB1, disrupted within both copies of the LAT gene. TB1 contains a 440-base-pair segment of bacteriophage lambda DNA in place of a 168-base-pair deletion within the transcribed portion of the LAT gene. The 2.0-kilobase LAT was not produced after infection of tissue culture cells with TB1, but a 0.7- to 0.8-kilobase RNA was expressed. TB1 did establish latent infection after corneal inoculation as efficiently as the parental virus, and its reactivation kinetics from explanted ganglia were similar to those of HFEM. During latent infection with TB1, HSV-1 transcripts were not detectable. Rescuant virus (TB1-R) contained intact LAT genes, synthesized full-length LAT transcripts during productive infection in tissue culture, and reactivated from ganglionic explants of latently infected mice with normal kinetics. Thus, any function these transcripts have in the reactivation process appears to include the region between the putative LAT promoter and the disruption in TB1--a region of approximately 1,600 nucleotides, 800 of which encode the LATs.

Single-Cell Analysis Identifies LY6D as a Marker Linking Castration-Resistant Prostate Luminal Cells to Prostate Progenitors and Cancer

The exact identity of castrate-resistant (CR) cells and their relation to CR prostate cancer (CRPC) is unresolved. We use single-cell gene profiling to analyze the molecular heterogeneity in basal and luminal compartments. Within the luminal compartment, we identify a subset of cells intrinsically resistant to castration with a bi-lineage gene expression pattern. We discover LY6D as a marker of CR prostate progenitors with multipotent differentiation and enriched organoid-forming capacity. Lineage tracing further reveals that LY6D+ CR luminal cells can produce LY6D- luminal cells. In contrast, in luminal cells lacking PTEN, LY6D+ cells predominantly give rise to LY6D+ tumor cells, contributing to high-grade PIN lesions. Gene expression analyses in patients' biopsies indicate that LY6D expression correlates with early disease progression, including progression to CRPC. Our studies thus identify a subpopulation of luminal progenitors characterized by LY6D expression and intrinsic castration resistance. LY6D may serve as a prognostic maker for advanced prostate cancer.

The prognostic value of the CT scan in conservatively treated patients with intracerebral hematoma

Prognostic factors for survival and neurological recovery were assessed in 42 patients with nontraumatic intracerebral hematoma (ICH) diagnosed by CT scan. None underwent surgical evacuation of hematoma. CT scans were used to determine location and volume of ICH and presence or absence of intraventricular hemorrhage (IVH). Only 11 patients (26%) died and 17 patients (40.5%) recovered fully. Mortality was associated with: 1) loss of consciousness as a presenting symptom (63.5% mortality rate versus 13% when there was no loss of consciousness at the onset; p less than 0.01). 2) extension of the bleeding into the ventricular system (45% mortality rate versus 9% when hemorrhages were confined to brain parenchyma; p less than 0.01). 3) location of hematoma in the posterior fossa (mortality rate of 43% versus 23% for intrahemispheric hematomas). Mortality was unaffected by age of patients and size of ICH. Full neurological and functional recovery occurred mainly when estimated volume of hematomas was less than 15 cc and with lobar hematomas regardless of size. In survivors there is CT evidence of complete resolution of ICH. Our data indicates a favourable outcome in a relatively large percentage of patients with ICH treated conservatively and therefore questions the need for surgical evacuation of hematoma.

Hereditary branching enzyme dysfunction in adult polyglucosan body disease: a possible metabolic cause in two patients

We describe 2 unrelated patients with adult polyglucosan body disease (APBD) diagnosed by sural nerve biopsy. Both patients were offspring of consanguineous marriages. They presented clinically with late onset pyramidal tetraparesis, micturition difficulties, peripheral neuropathy, and mild cognitive impairment. Magnetic resonance imaging of the brain revealed extensive white matter abnormalities in both. In search of a possible metabolic defect, we evaluated glycogen metabolism in these patients and their clinically unaffected children. Branching enzyme activity in the patients' polymorphonuclear leukocytes was about 15% of control values, whereas their children displayed values of 50 to 60%, suggesting a possible autosomal recessive mode of transmission. This is the first report of an inherited metabolic defect in patients with adult polyglucosan body disease. We suggest that branching enzyme dysfunction may be implicated in the pathogenesis of some patients with adult polyglucosan body disease.

Herpes simplex virus latent infection in the nervous system

Herpes simplex virus (HSV) establishes a latent infection in the human peripheral nervous system and can cause recurrent disease by reactivation. Intensive effort has been directed in recent years to unveil the molecular, cellular and immune mechanisms, as well as the virus-host interactions associated with latent HSV infection. The aim of this review is to summarize current knowledge regarding the site of latent infection, the molecular phenomena of latency, and the mechanisms of the various stages of HSV-1 latent infection in the nervous system, relating them where possible to the human situation. Specifically, the following biological questions are addressed: (1) How does this lytic virus survive in the nervous system and why can it establish a lifelong latent infection in nerve cells? (2) What advantage is conferred on HSV by establishing latent infection in nervous tissue? (3) What can be gathered from the accumulated knowledge on latency about the pathogenesis of herpes simplex encephalitis?

Basophils are not the key antigen-presenting cells in allergic patients

BACKGROUND

Recent data obtained in mouse models have initiated a controversy whether basophils are the key antigen-presenting cells (APCs) in allergy. Here, we investigate whether basophils are of importance for the presentation of allergen and the induction of T cell proliferation in allergic patients.

METHODS

T cells, basophils, and APCs depleted of basophils were purified from allergic patients. Co-culture systems based on purified major allergens were established to study allergen-specific T cell responses using proliferation assays.

RESULTS

Only co-cultures of T cells with APCs depleted of basophils but not with basophils proliferated in response to allergen. Even addition of IL-3 to T cell-basophil co-cultures failed to induce allergen-specific T cell proliferation.

CONCLUSIONS

Our data demonstrate by classical in vitro proliferation assays that basophils are not key antigen-presenting cells that promote T cell proliferation in secondary immune responses to allergen in allergic patients.

The assessment of changes in brain volume using combined linear measurements. A CT-scan study

All linear measurements employed for evaluation of brain atrophy, were performed on 148 computed tomograms of patients aged 28 to 84 without evidence of any nervous system disorder. These included size of lateral, third and fourth ventricles, width of the Sylvian and frontal interhemispheric fissures and cortical sulci and size of the pre-pontine cistern. Various parameters indicated decrease in brain mass with age. Since the atrophic process is a diffuse phenomenon, integration of several measurements evaluating separate brain regions was made. The bicaudate ratio and the Sylvian fissure ratio (representing both central and cortical atrophy) were combined arithmetically, resulting in a correlation of 0.6390 with age (P less than 0.0005). With a computed canonical correlation analysis; a formula was obtained which combined measurements of the lateral and third ventricles, the Sylvian fissure and the pre-pontine cistern. This formula yielded a correlation of 0.67795 (P less than 0.0005). These linear measurements will allow simple and reliable assessement of reduction in brain volume during the normal aging process and in disorders accompanied by brain atrophy.

Recurrence of acute disseminated encephalomyelitis at the previously affected brain site

BACKGROUND

Acute disseminated encephalomyelitis (ADEM) is a usually monophasic demyelinating disorder of the central nervous system. Recurrences pose a diagnostic challenge because they can be overlooked or suggest an alternative diagnosis.

OBJECTIVE

To examine the frequency, nature, and outcome of recurrent ADEM.

DESIGN

Review of the medical records of patients diagnosed in our institution as having ADEM between January 1, 1983, and May 31, 1998. Recurrences were defined as appearance of new symptoms and signs at least 1 month after the previous episode.

RESULTS

Five (24%) of 21 patients with ADEM developed recurrent disease episodes. In all, diagnosis was confirmed by brain biopsy. One patient had 4 disease episodes, 2 had 3, and the other 2 each had 2. Recurrence appeared 1.5 to 32 months after initial presentation and involved the same brain territory in 6 of 9 recurrences in 3 of 5 patients. In 2 patients, recurrences included neuropsychiatric signs. A good response to corticosteroid therapy was observed in 10 of 13 of treated ADEM attacks: in 3 of the 4 treated initial events and in 7 of 9 recurrences.

CONCLUSIONS

Recurrent ADEM may be more prevalent than previously recognized. Patients who relapse tend to have more than 1 recurrence that usually involves, clinically and radiologically, a brain territory that was affected before and can simulate a space-occupying lesion that requires histologic diagnosis. Neuropsychiatric features may be the main presentation of a relapse. Since recurrent ADEM is a corticosteroid-responsive condition, awareness and early diagnosis are mandatory.

Isolation and analysis of bacterial cobamides by high-performance liquid chromatography

Cyanocobamides were extracted from diverse bacterial species, purified by XAD-4 and neutral aluminum oxide column chromatography, and separated by isocratic reversed-phase high-performance liquid chromatography (HPLC). Retention times are given for seven cobamide types: dicyanocobinamide (factor B), Co alpha-(alpha-benzimidazolyl)-Co beta-cyanocobamide, Co alpha-(5-hydroxybenzimidazolyl)-Co beta-cyanocobamide (factor III), Co alpha-(5-methoxybenzimidazolyl)-Co beta-cyanocobamide (factor IIIm), Co alpha-(5-methylbenzimidazolyl)-Co beta-cyanocobamide, cyanocob(III)alamin (vitamin B-12) and Co alpha-(naphthimidazolyl)-Co beta-cyanocobamide. Other Co beta-ligandyl-cobamides such as hydroxycobamide and the light-sensitive methyl-, acetyl-, propyl-, and adenosylcobamides were separated by HPLC in a gradient mode. The recovery of total cell cobamide after extraction, purification, and separation was 75-80%. The method was useful in preparative and analytical work. Less than 10 ng cyanocobamide was detectable.

Guillain-Barré syndrome after epidural anesthesia: direct nerve root damage may trigger disease

Guillain-Barré syndrome (GBS) appeared in four patients 1 to 2 weeks after epidural anesthesia. In all patients, clinical diagnosis was confirmed by CSF findings and nerve conduction velocity studies. Although epidural anesthesia has not been listed as an antecedent event in GBS, evidence for the relationship has been previously reported. Interaction between the anesthetic agents and peripheral nervous system myelin or local trauma to roots may initiate a cascade of immunologic events that result in the demyelinating neuropathy.