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Each olfactory cortical hemisphere receives ipsilateral odor information directly from the olfactory bulb and contralateral information indirectly from the other cortical hemisphere. Since neural projections to the olfactory cortex (OC) are disordered and nontopographic, spatial information cannot be used to align projections from the two sides like in the visual cortex. Therefore, how bilateral information is integrated in individual cortical neurons is unknown. We have found, in mice, that the odor responses of individual neurons to selective stimulation of each of the two nostrils are significantly correlated, such that odor identity decoding optimized with information arriving from one nostril transfers very well to the other side. Nevertheless, these aligned responses are asymmetric enough to allow decoding of stimulus laterality. Computational analysis shows that such matched odor tuning is incompatible with purely random connections but is explained readily by Hebbian plasticity structuring bilateral connectivity. Our data reveal that despite the distributed and fragmented sensory representation in the OC, odor information across the two hemispheres is highly coordinated., Competing Interests: The authors declare no competing financial interests., (Copyright © 2024 Grimaud et al.)

Rodents can learn from exposure to rewarding odors to make better and quicker decisions. The piriform cortex is thought to be important for learning complex odor associations; however, it is not understood exactly how it learns to remember discriminations between many, sometimes overlapping, odor mixtures. We investigated how odor mixtures are represented in the posterior piriform cortex (pPC) of mice while they learn to discriminate a unique target odor mixture against hundreds of nontarget mixtures. We find that a significant proportion of pPC neurons discriminate between the target and all other nontarget odor mixtures. Neurons that prefer the target odor mixture tend to respond with brief increases in firing rate at odor onset compared to other neurons, which exhibit sustained and/or decreased firing. We allowed mice to continue training after they had reached high levels of performance and find that pPC neurons become more selective for target odor mixtures as well as for randomly chosen repeated nontarget odor mixtures that mice did not have to discriminate from other nontargets. These single unit changes during overtraining are accompanied by better categorization decoding at the population level, even though behavioral metrics of mice such as reward rate and latency to respond do not change. However, when difficult ambiguous trial types are introduced, the robustness of the target selectivity is correlated with better performance on the difficult trials. Taken together, these data reveal pPC as a dynamic and robust system that can optimize for both current and possible future task demands at once., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Berners-Lee et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Accurately measuring respiration in laboratory rodents is essential for many fields of research, including olfactory neuroscience, social behavior, learning and memory, and respiratory physiology. However, choosing the right technique to monitor respiration can be tricky, given the many criteria to take into account: reliability, precision, and invasiveness, to name a few. This review aims to assist experimenters in choosing the technique that will best fit their needs, by surveying the available tools, discussing their strengths and weaknesses, and offering suggestions for future improvements.

The calcium-activated chloride channel anoctamin-2 (Ano2) is thought to amplify transduction currents in olfactory receptor neurons (ORNs), a hypothesis supported by previous studies in dissociated neurons from Ano2 -/- mice. Paradoxically, despite a reduction in transduction currents in Ano2 -/- ORNs, their spike output for odor stimuli may be higher. We examined the role of Ano2 in ORNs in their native environment in freely breathing mice by imaging activity in ORN axons as they arrive in the olfactory bulb glomeruli. Odor-evoked responses in ORN axons of Ano2 -/- animals were consistently larger for a variety of odorants and concentrations. In an open arena, Ano2 -/- animals took longer to approach a localized odor source than Ano2 +/+ animals, revealing clear olfactory behavioral deficits. Our studies provide the first in vivo evidence toward an alternative or additional role for Ano2 in the olfactory transduction cascade, where it may serve as a feedback mechanism to clamp ORN spike output.

The broadly-distributed, non-topographic projections to and from the olfactory cortex may suggest a flat, non-hierarchical organization in odor information processing. Layer 2 principal neurons in the anterior piriform cortex (APC) can be divided into 2 subtypes: semilunar (SL) and superficial pyramidal (SP) cells. Although it is known that SL and SP cells receive differential inputs from the olfactory bulb (OB), little is known about their projections to other olfactory regions. Here, we examined axonal projections of SL and SP cells using a combination of mouse genetics and retrograde labeling. Retrograde tracing from the OB or posterior piriform cortex (PPC) showed that the APC projects to these brain regions mainly through layer 2b cells, and dual-labeling revealed many cells extending collaterals to both target regions. Furthermore, a transgenic mouse line specifically labeling SL cells showed that they send profuse axonal projections to olfactory cortical areas, but not to the OB. These findings support a model in which information flow from SL to SP cells and back to the OB is mediated by a hierarchical feedback circuit, whereas both SL and SP cells broadcast information to higher olfactory areas in a parallel manner.

For hundreds of years, the sense of smell has generated great interest in the world literature, oenologists, and perfume makers but less of scientists. Only recently this sensory modality has gained new attraction in neuroscience when original tools issued from physiology, anatomy, or molecular biology were available to decipher how the brain makes sense of olfactory cues. However, this move was promptly dampened by the difficulties of developing quantitative approaches to study the relationship between the physical characteristics of stimuli and the sensations they create. An upswing of olfactory investigations occurred when genetic tools could be used in combination with devices borrowed from the physics of light (a hybrid technique called optogenetics) to scrutinize the olfactory system and to provide greater physiological precision for studying olfactory-driven behaviors. This review aims to present the most recent studies that have used light to activate components of the olfactory pathway, such as olfactory receptor neurons, or neurons located further downstream, while leaving intact others brain circuits. With the use of optogenetics to unravel the mystery of olfaction, scientists have begun to disentangle how the brain makes sense of smells. In this review, we shall discuss how the brain recognizes odors, how it memorizes them, and how animals make decisions based on odorants they are capable of sensing. Although this review deals with olfaction, the role of light will be central throughout., (© 2016 Grimaud and Lledo; Published by Cold Spring Harbor Laboratory Press.)

Two 4 L tubular microbial fuel cells (MFCs) were installed in a municipal wastewater treatment facility and operated for more than 400 days on primary effluents. Both MFCs removed 65-70% chemical oxygen demand (COD) at a hydraulic retention time (HRT) of 11 h and reduced about 50% suspended solids. The COD removal rates were about 0.4 (total) or 0.2 (soluble) kg m(-3) day(-1). They could handle fluctuation, such as emptying the anode for 1-3 days or different HRTs. The preliminary analysis of energy production and consumption indicated that the two MFCs could theoretically achieve a positive energy balance and energy consumption could be reduced using larger tubing connectors. Through linkage to a denitrifying MFC, the MFC system improved the removal of total nitrogen from 27.1 to 76.2%; however, the energy production substantially decreased because of organic consumption in the denitrifying MFC. Establishing a carbon (electron) balance revealed that sulfate reduction was a major electron scavenger (37-64%) and methane production played a very minor role (1.3-3.3%) in electron distribution. These results demonstrate the technical viability of MFC technology outside the laboratory and its potential advantages in low energy consumption, low sludge production, and energy recovery from wastes.

To examine the feasibility of integrating microbial fuel cells (MFCs) into an activated sludge process, three MFCs with different ion exchange membranes and/or cathode catalysts were installed in an aeration tank to treat primary effluent. Both contaminant treatment and electricity generation were studied during the operation for more than 400 days. The effects of membrane/catalysts on MFC performance were not observed, likely due to the low removal of chemical oxygen demand (COD) (<53%) caused by low electricity generation. The MFCs did not achieve any obvious removal of nutrients. The produced energy was lower than the theoretic energy consumption. The performance was seriously affected by cathode biofouling, variation of wastewater quality, and other operating conditions. Unlike prior lab studies by others, the results of this study suggest that MFCs may not be suitable for deployment in an aeration tank, unless the key problems such as biofouling are solved., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The long-term performance of sludge treatment in microbial fuel cells (MFCs) was examined by operating two MFCs for almost 500 days. In Phase I, one MFC fed with primary sludge removed 69.8±24.1% of total chemical oxygen demand (TCOD) and 68.4±17.9% of volatile suspended solids (VSS); the other MFC with digested sludge reduced 36.2±24.4% of TCOD and 46.1±19.2% of VSS. In Phase II, both MFCs were operated as a two-stage system that removed 60% of TCOD and 70% of VSS from the primary sludge. An energy analysis revealed that, although the total energy in the MFC system was comparable with that of anaerobic digesters, the electric energy had a minor contribution and methane gas still dominated the total energy production. The results suggest that MFCs may not be suitable for treating primary sludge for energy recovery, but could potentially be used to polish the effluent from anaerobic digesters., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The use of spiral spacers to create a helical flow for improving electricity generation in microbial fuel cells (MFCs) was investigated in both laboratory and on-site tests. The lab tests found that the MFC with the spiral spacers produced more electricity than the one without the spiral spacers at different recirculation rates or organic loading rates, likely due to the improved transport/distribution of ions and electron mediators instead of the substrates because the organic removal efficiency was not obviously affected by the presence of the spiral spacers. The energy production in the MFC with the spiral spacers reached 0.071 or 0.073 kWh/kg COD in either vertical or horizontal installment. The examination of the MFCs installed in an aeration tank of a municipal wastewater treatment plant confirmed the advantage of using the spiral spacers. Those results demonstrate that spiral spacers could be an effective approach to improve energy production in MFCs., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: There have been few epidemiologic studies on neuromyelitis optica (NMO) and none used the recent 2006 diagnostic criteria. Here we describe the clinical, laboratory, MRI, and disability course of NMO in a French cohort of 125 patients., Methods: We performed an observational, retrospective, multicenter study. Data were collected from September 2007 through August 2008, corresponding to the endpoint of the study. We identified 125 patients fulfilling the 2006 NMO criteria. Selection was made using hospital files and a specific clinical questionnaire for NMO., Results: Mean age at onset was 34.5 years (range 4-66) with a mean disease duration of 10 +/- 7.8 years at the endpoint. The patients were mainly (87%) Caucasian, with a female:male ratio of 3:1. In 90% of cases, the association of optic neuritis, longitudinal extensive myelitis, and a Paty-negative initial brain MRI was sufficient to fulfill the supportive criteria. Eighty-eight percent of patients were treated with immunosuppressive therapies. Median delay from onset to Expanded Disability Status Scale (EDSS) score 4 was 7 years; score 6, 10 years; and score 7, 21 years. The first episode of myelitis was immediately followed by an EDSS score > or = 4 in 37.3% of cases, and a severe residual visual loss was observed in 22% of patients after the first episode of optic neuritis. Multivariate analysis did not reveal any predictors of a poor evolution other than a high number of MRI brain lesions at diagnosis, which were predictive of a residual visual acuity < or = 1/10., Conclusions: Our demographic data provide new data on disability in patients with neuromyelitis optica, most of whom were receiving treatment.

Objectives: The EDMUS system is a clinical database specifically tailored to the description of multiple sclerosis (MS). The EVALUED (Evaluation of the EDMUS system) study is an European project with two objectives: 1) to assess the inter-examiner reliability of the whole EDMUS system; 2) to validate the EDMUS-Grading Scale (EGS),which is a simplified version of the Kurtzke Disability Status Scale (DSS)., Methods: The protocol included 12 neurologists working in pairs within six European centres (Bari, Basel, Florence, London, Lyon, Würzburg). They assessed independently 30 MS patients in their centre, filling in the EDMUS forms. The reliability of the system was assessed on selected key items in the history of the MS onset, the clinical course and the disease course classification. The clinical examination of the patients permitted an assessment of the Kurtzke Expanded Disability Status Scale (EDSS) and the EGS. Level of agreement was measured in terms of kappa and weighted kappa indexes whenever appropriate., Results: The study included 180 patients with definite or probable MS of whom 37% were males. Age was 35.8+/-9.6 years (mean +/- SD), disease duration 7.8+/-5.7 years, and mean EDSS score 4.1+/-2.2. The disease course was relapsing-remitting in 67%, secondary progressive in 22%, and progressive from disease onset in 11%. For key items of the history, the inter-examiner reliability level ranged from moderate to excellent. Concerning the disability scales, perfect agreement was reached in 59 % for EDSS and 78% for EGS. The close correlation and linear association (r=0.94, p<0.0001) between both scales demonstrated EGS's construct validity., Conclusion: The EDMUS system allows a consistent clinical description of MS using a common language. This standardized follow-up of MS patients is valuable especially in studies requiring a critical mass of informative patients.

Background and Purpose: Previously reported quantitative parameters for the magnetization transfer ratio (MTR) do not give identical results, which can limit their ability to differentiate normal from diseased tissue and render them vulnerable to variations among MR systems. Our purpose was to systematically study different MTR metrics; propose a new MTR histogram parameter, AMTR(2/3); and compare AMTR(2/3) with existing parameters in a study of multiple sclerosis (MS)., Methods: Seven conventional MTR parameters were proposed: global and mean MTR; peak height and position of the histogram; and percentiles MTR25, MTR50, and MTR75. Additionally, we investigated a parameter, AMTR(2/3), to indicate the normalized pixel count (area under the histogram curve) inside the band size of two-thirds MTR histogram peak height. All parameters were measured in 10 patients with relapsing-remitting MS (group A), 10 healthy control subjects from the same imaging center as that of patients (group B), and four healthy control subjects from an outside institution (group C). Comparison of findings was performed between groups A and B to assess the discriminating ability of MTR parameters and groups B and C to evaluate intersystem variations., Results: All MTR parameters differed between groups A and B, but the difference was significant for only global MTR, mean MTR, MTR25, and AMTR(2/3). With the exception of AMTR(2/3), all parameters differed significantly between the two control groups., Conclusion: AMTR(2/3) is less sensitive to MR imaging system variations than are other MTR parameters and was most effective in differentiating patients with MS from healthy control subjects. This finding supports the use of AMTR(2/3) in multicenter MT MR imaging studies of MS.

Leprosy, also known as Hansen's disease, is a chronic, infectious disease caused by Mycobacterium leprae. Bacilli localize preferentially in the skin and peripheral nerves and have a propensity to cause nerve damage. The resulting disability has caused great suffering for victims in many countries. Despite recent advances in the immunopathogenesis, epidemiology and prognostic factors of leprosy nerve damage, many aspects of the disease have remained enigmatic. The spectrum of clinical and pathological manifestations of the disease ranges from lepromatous to tuberculoid, depending on the host's T-cell-mediated immune response. Diagnosis is based on three criteria: characteristic skin lesions in association with thickened nerves, demonstration of acid fast bacilli in slit skin smears, and histopathology of skin biopsies. Nerve biopsy is necessary to establish the diagnosis of pure "neural leprosy". In developed countries, the diagnosis is suspected when a patient who has stayed in an endemic area suffers from a peripheral neuropathy of unknown etiology. To facilitate determination of the appropriate antibiotic regimen, patients are classified as either paucibacillary or multibacillary. Some patients may have multibacillary leprosy in nerves and paucibacillary leprosy in skin, which emphasizes the usefulness of nerve biopsy. The course of the disease is often complicated by immune mediated "reactions", which can rapidly lead to further nerve damage, namely reversal reaction and erythema nodosum leprosy. However, nerves are often functionally impaired before developing obvious symptoms such as skin reactions or nevralgia (silent neuropathy). Early recognition and prompt treatment with corticosteroids of leprous reactions and "silent neuropathies" is very important to prevent disability with all its attendant problems. Research progress from clinical trials may improve current methods of prevention and treatment of nerve damage in leprosy.

The purpose of this review of the literature is to analyze the contribution of magnetization transfer (MT) imaging techniques in understanding the various characteristics of multiple sclerosis. MT imaging allows contrast augmentation by use of magnetization transfer contrast. MT imaging allows lesion characterization by means of quantification of the degree of signal loss due to magnetization transfer contrast by a magnetization transfer ratio. It is used as an indicator of tissue destruction; in particular, to demyelination. Both applications of MT imaging in multiple sclerosis are studied in this review, as well as the methodological and technical limitations.

A method is presented for fully automated detection of Multiple Sclerosis (MS) lesions in multispectral magnetic resonance (MR) imaging. Based on the Fuzzy C-Means (FCM) algorithm, the method starts with a segmentation of an MR image to extract an external CSF/lesions mask, preceded by a local image contrast enhancement procedure. This binary mask is then superimposed on the corresponding data set yielding an image containing only CSF structures and lesions. The FCM is then reapplied to this masked image to obtain a mask of lesions and some undesired substructures which are removed using anatomical knowledge. Any lesion size found to be less than an input bound is eliminated from consideration. Results are presented for test runs of the method on 10 patients. Finally, the potential of the method as well as its limitations are discussed.

Magnetic resonance imaging (MRI) is frequently used to monitor new treatments in multiple sclerosis (MS), but its role is limited by the uncertain relationship between MRI parameters and clinical disability. A brain MRI study using nine MRI parameters was undertaken in 15 MS patients with a wide spectrum of disability to evaluate the relationship between each parameter and disability. A strong correlation was found between disability (measured using Kurtzke's EDSS) and total lesion load on both proton density (PD; r = 0.79) and T1 (r = 0.71) weighted sequences. There was also a strong correlation of disability with average lesion magnetisation transfer ratio (MTR; r = -0.74) and calculated T1 (r = 0.71) but not with calculated T2 or the average signal intensity of lesions on the conventional T1-weighted, PD-weighted and heavily T2-weighted images. Thus, four parameters which measured either the extent of lesions (PD lesion load) or their pathological severity (MTR, calculated T1, hypointense T1-lesion load) were correlated significantly with disability. While this suggests that such parameters will be useful in treatment trial monitoring, further multi-parameter MRI studies, of larger cohorts and using a wider range of techniques, are indicated.

Multiple sclerosis (MS) is the most common chronic disabling neurological disease affecting young women. Paradoxically, our knowledge of the relationship between pregnancy and MS is limited. However, several conclusions emerge from the literature: 1) The rate of relapse in MS decreases during pregnancy, and it rises significantly during the first three months post partum before coming back to its level prior to pregnancy. 2) Although pregnancy and delivery cause changes of the relapse rate, they have no influence on mid and long term residual disability. 3) Breast-feeding and epidural analgesia do not seem to have any deleterious effect on the disease. 4) Lastly, MS does not seem to influence pregnancy, delivery or the child's health. The studies available to date suffer from methodological limitations. They need to be confirmed by prospective studies. This is the purpose of the study entitled "Pregnancy in multiple sclerosis, PRIMS", which has been carried out since 1992 at the European level.

We report the case of a 48-year-old patient who developed acute onset bilateral, peripheral motor dysfunction in the arms and forearms. Clinical history, electromyography and laboratory tests confirmed the diagnosis of peripheral neuropathy caused by lead poisoning from the domestic water supply. The EMG showed axonal alterations. Improvement was observed after treatments with chelating agents and removal of the source of poisoning. This case provides the opportunity to recall the traditional 1889 Dejerine classification of lead-related peripheral neuropathies and is a warning signal that lead poisoning remains a problem in peri-urban areas of developed countries.

Quantitative assessment of Magnetic Resonance Imaging (MRI) lesion load of patients with multiple sclerosis (MS) is the most objective approach for a better understanding of the history of the pathology, either natural or modified by therapies. To achieve an accurate and reproducible quantification of MS lesions in conventional brain MRI, an automatic segmentation algorithm based on a multiresolution approach using pyramidal data structures is proposed. The systematic pyramidal decomposition in the frequency domain provides a robust and flexible low level tool for MR image analysis. Context-dependent rules regarding MRI findings in MS are used as high level considerations for automatic lesion detection.

Three characteristic features describe our understanding of the clinical course and outcome in multiple sclerosis: a validated statistical model of disease progression, wide interindividual variability, and a fixed rate of progression in an individual patient. However for and individual patient, it is still impossible to derive a precise and exact prediction of disease outcome, the only reliable method is the deterministic approach developed by Fog and Linneman in 1970 which consists in objective quantitative neurological examinations performed at three month intervals over several years in the same patient. In routine practice, this method in rather unrealistic. Bran MRI data with conventional techniques are also poorly discriminant. Conversely, it may be anticipated that new magnetic resonance techniques, more sensitive to axonal loss, demyelinization and gliosis, will provide reliable answers to this issue upon which therapeutic decisions depend.

In this study, we evaluated the intra- and interobserver variabilities in measuring lesion load of brain MRI abnormalities present on proton-density scans from patients with MS, using using both manual outlining or a semiautomated local thresholding technique (LTT). We also evaluated how these variabilities were affected by the use of standard rules for lesion load measurements, training, and different measurement strategies. The intraobserver variabilities obtained after establishing rules for lesion load measurements and training were not significantly different from those obtained before any consensus among the observers, both for manual outlining and for the LTT. On the contrary, the interobserver variabilities obtained with manual outlining or the LTT were significantly reduced when rules for lesion load measurements were used. For manual outlining, the intraobserver variability did not significantly change when the measurements were performed after an experienced radiologist identified lesions or when using adjacent slices and the corresponding T2-weighted images as reference for lesion identification. On the contrary, for the LTT, the intraobserver variability was significantly reduced by the use of the radiologic marking. The interobserver variabilities for both manual outlining and the LTT were reduced compared with the free condition when these measurement strategies were used. Our findings demonstrate that both lesion identification and outlining are important sources of variation for MRI lesion load measurements in MS and that there are simple strategies to reduce such variation that might be useful when planning clinical trials.

Magnetic resonance imaging (MRI) has provided considerable insight into the pathological process and disease activity and progression in multiple sclerosis. MRI has become an important tool for the diagnosis of multiple sclerosis, and increasingly for monitoring treatment trial. The growing use of MRI calls for careful consideration in applications so that the technology is not misused. Here we propose a summary of the literature on MRI in application in clinical neurology.

An increased risk of cancer has been reported in patients treated with azathioprine. To assess the long-term risk of neoplasia in azathioprine-treated multiple sclerosis (MS) patients, we conducted a case-control study using the Lyon Multiple Sclerosis Database. From the 1,191 MS patients included in the database, we identified patients who developed cancer before December 31, 1991. Each case was then matched to three cancer-free MS controls by gender, date of birth, and date of MS onset. A matched analysis was performed to compare cases and controls for exposure to azathioprine therapy during the same follow-up period. Twenty-three MS patients with cancer were identified: 17 solid tumors, 2 skin carcinomas, 4 hematopoietic cancers. Cases had a mean age of 34.5 years +/- 10.2 (+/- SD) at clinical onset of MS and have been followed up for an average 13.8 years +/- 8.1 before being diagnosed with cancer. Fourteen cases (61%) and 34 controls (49%) had been treated with azathioprine for at least 1 month after being diagnosed with MS (adjusted odds ratio = 1.7; 95% confidence interval [CI], 0.6 to 4.6). When assessing risk associated with different durations of azathioprine therapy compared with no treatment at all, we found that MS patients had an increase in cancer risk of 1.3 (95% CI, 0.4 to 4.0) when treated less than 5 years, of 2.0 (95% CI, 0.4 to 9.1) when treated 5 to 10 years, and of 4.4 (95% CI 0.9 to 20.9) when treated more than 10 years. Similar results were obtained when assessing cancer risk associated with cumulative doses of azathioprine ever taken. This case-control study suggests that the overall long-term risk of cancer from azathioprine is low in MS patients. The results are suggestive of a dose-response relationship with no significant risk during the first years of treatment and a possible increased risk after about 10 years of continuous therapy. Further studies are needed to better assess the risk-benefit ratio of azathioprine in MS.

Substrate specificity of the acyltransferase activity of the lipase (EC 3.1.1.3) from Candida parapsilosis CBS 604 was studied in aqueous media. The specificity toward both acid and alcohol parts of a large number of acylglycerols and aliphatic esters was investigated. This lipase showed a high activity in the presence of esters with long-chain fatty acids and particularly unsaturated fatty acids with a cis-delta 9 double bond. It was observed that the activity profile depended not only on the alcohol part of the acyl ester, but also on the temperature of the reactant medium. The best lipid substrates had their melting point between -40 to +20 degrees C, 14 to 18 carbon atoms in the acyl group and 1 to 4 carbon atoms in the alkyl group. The enzyme, defined as an acyltransferase in a previous paper, showed a high affinity for primary and secondary alcohols with a short carbon chain (1 to 5 carbon atoms) as acyl acceptors. The influence of free alcohols in the reactant medium on the hydrolysis and alcoholysis activities of the enzyme is discussed. Two phenomena seem to be involved, depending on the alcohol: competition with water for the acyltransfer reaction and lipid substrate dilution when the alcohol places at the oil/water interface.

In leprosy, the early detection of peripheral nerve damage is essential for the prevention of disability. To date, there is no consensus on what is the best clinical test to reveal such abnormalities. In this prospective study we examined the effectiveness of five clinical tests to assess radial cutaneous nerve (RCN) damage (the most frequently involved). Light touch was assessed by two nylon threads (based on the Semmes-Weinstein monofilaments testing technique) bent on the skin at a pressure of 0.5 (N. 4 nylon) and 0.2 gram (N. 5 nylon). Pinprick and cooling sensations were examined by a needle and a drop of ether. The nerve thickness was assessed by palpation. Sensory findings were then compared to sensory nerve conduction values of the RCN and a sensitivity analysis was performed. The patient group consisted of 108 consecutive new leprosy sufferers (138 RCN) who attended the Institut de Léprologie Appliquée de Dakar during one year. Diagnosis and classification were based on Ridley and Jopling's criteria (clinical examination, skin smears and biopsy). Normal values were determined among 22 healthy subjects (44 RCN). The best tests in term of sensitivity were palpation (.60), N. 5 nylon (.65) and N. 5 + palpation (.79). Their positive predictive values were .84 (palpation), .94 (N. 5 nylon) and .83 (N. 5 + palpation). The best tests in term of area under the curve were palpation (.66), N. 5 nylon (.71) and N. 5 + palpation (.78). The results remain the same for the lepromatous or tuberculoid leprosy patients.(ABSTRACT TRUNCATED AT 250 WORDS)

In leprosy, ulnar neuritis is considered to be selectively localised at the elbow and is often treated by surgical decompression when pain and/or neurological deficit occurs. The aim of this prospective study is to assess the prevalence, localisation and severity of ulnar nerve damage in leprosy. Motor nerve conduction velocity (MNC) was measured at 3 different segments: arm, elbow and forearm, and was expressed both in meters/second and percentage of the mean normal values found in our laboratory or as reported in other studies. The patient group consisted of 123 consecutive new leprosy sufferers (228 ulnar nerves only) who attended the Institut de Léprologie Appliquée de Dakar over the period of one year. Diagnosis and classification were based on Ridley & Jopling's criteria, including skin and nerve biopsy. Mean MNC was reduced by 13.5 m/s at the arm, 19.8 m/s at the elbow and 7.8 m/s at the forearm as compared to the mean normal values. Increased distal latency as an isolated finding was rare (0.9%). Mean MNC was more reduced in the BL, LL (lepromatous) than in the TT, BT (tuberculoid) subgroups, despite similar disease durations (22.3 +/- 18.7 months and 24.2 +/- 26.4 months respectively (n.s.). Using different normal MNC values did not affect the conclusion: we did not see any selective slowing of ulnar MNC at the elbow suggesting that nerve damage is not primarily related to mechanical factors.

We report the findings of an epidemiological study conducted between June 1989 and February 1990 on a population of leprosy patients in southern Senegal (Bignona major endemic disease sector). Two types of population were studied: patients living in urban areas and inmates of leprosaria. The global HIV seroprevalence (HIV 2 in all cases) of the leprosy-patient population was 1.15% (3/257): 0.8% (1/130) for the urban group and 1.5% (2/127) for the leprosaria. The seroprevalence rate does not differ significantly from that for the control group studied and for blood donors (1/221). The diagnosis of leprosy in the seropositive subjects had been established before 1980. None of them showed any sign of relapse. The immunodepression associated with the presence of HIV was only moderate: it was reflected in a lowering of the CD4 count and of the CD4/CD8 ratio, but with no clinical sign of AIDS.

The purpose of the study is to propose a simple and reproducible test for assessing nerve damage in leprosy. It is applied to the sensory branch of the radial nerve of leprosy patients, prior to any treatment. Skin sensitivity is measured by means of a needle, a drop of ether and some calibrated filaments. These three tests are collated and compared with the results of electromyographic examination of the nerve. The filament calibrated to 0.2 grams gives optimum sensitivity (0.79) and excellent specificity (0.95) in relation to the electromyographic test. Its routine use in the field is simple and reproducible and should result in a greater number of patients receiving the treatment they need.

Lipase activity can be spectrophometrically measured in an optically clear medium using long chain fatty thioesters of 1-mercapto-2,3-propanediol or 2-mercaptoethanol as substrates. With hexamethylphosphoric triamide solutions of these thiosubstrates, the Michaëlis-Menten constants of lipase from Rhizopus arrhizus were determined. The effects of calcium chloride and of bovine serum albumin on the enzyme activity were established.