Bickerstaff's brainstem encephalitis mimicking herpetic encephalomyelitis in a liver transplant patient with anti-GQ1b antibodies.

A woman in her late 70s with a history of liver transplant presented with ophthalmoplegia, ataxia, areflexia, positive Babinski's sign and reduced consciousness. This followed an antecedent illness in the form of a herpes zoster infection. MRI of the brain/spinal cord, cerebrospinal fluid analysis with viral PCR and routine blood tests were normal, and tacrolimus neurotoxicity was ruled out. Serum anti-GQ1b antibodies were positive. A diagnosis of Bickerstaff's brainstem encephalitis was made, forming part of the continuum that involves Miller-Fisher syndrome, entitled the 'anti-GQ1b syndrome'. Complete recovery ensued without intravenous immunoglobulins or plasma exchange. The role of monitoring anti-ganglioside pattern change to predict or confirm disease recurrence and disease severity is further discussed.

The dynamics of the detection of 226Ra in water by scintillation counting in nonequilibrium conditions.

The conventional methods for the 226Ra determination by liquid scintillation counting require to attain secular equilibrium between 226Ra and 222Rn prior to the counting. This study describes a method that allows the immediate counting of a sample after the dissolution of Ba(Ra)SO4 in EDTA. This results from a detailed modelling of the activity of the parent 226Ra and its daughters in both the aqueous and organic scintillator phases. This methodology was tested on standard solutions of 226Ra showing promising results.

IgM paraprotein and anti-MAG sensory polyneuropathy associated with Waldenstrom's macroglobulinaemia and medullary carcinoma of the thyroid.

A previously fit and well 76-year-old man, presented with distal lower limb sensory symptoms suggestive of peripheral sensory neuropathy, associated with positive anti-MAG antibodies (myelin associated glycoprotein) and IgM paraprotein. Bone marrow biopsy showed lymphoplasmocytoid lymphoma (Waldenstrom's macroglobulinaemia, WM), consequently positive for MYD88 mutation. He subsequently developed medullary carcinoma of the thyroid, most likely secondary to WM. He underwent a successful total thyroidectomy and four treatment doses of rituximab, which proved beneficial. He is currently stable and under multidisciplinary monitoring. His sensory symptoms have improved following rituximab treatment and his WM is under control.

Neuromyelitis optica spectrum disorder (NMOSD) presenting as acute transverse myelitis with positive aquaporin 4 antibodies.

An 80-year-old, previously healthy patient presents with acute transverse myelitis with sensory level at T8. The MRI scan of the spinal cord showed longitudinal extensive transverse myelitis, and she tested positive for aquaporin 4 antibodies in serum. She received treatment with intravenous and oral steroids, with no improvement and then underwent plasma exchange. She was then started on azathioprine for prevention of relapses, while continuing physiotherapy and occupational therapy. Eventually, she was transferred to a specialised spinal cord centre for long-term rehabilitation.

Bilateral, vertical supranuclear gaze palsy following unilateral midbrain infarct.

A 60-year-old man recently admitted for bipedal oedema, endocarditis and a persistently positive COVID-19 swab with a history of anticoagulation on rivaroxaban for atrial fibrillation, transitional cell carcinoma, cerebral amyloid angiopathy, diabetes and hypertension presented with sudden onset diplopia and vertical gaze palsy. Vestibulo-ocular reflex was preserved. Simultaneously, he developed a scotoma and sudden visual loss, and was found to have a right branch retinal artery occlusion. MRI head demonstrated a unilateral midbrain infarct. This case demonstrates a rare unilateral cause of bilateral supranuclear palsy which spares the posterior commisure. The case also raises a question about the contribution of COVID-19 to the procoagulant status of the patient which already includes atrial fibrillation and endocarditis, and presents a complex treatment dilemma regarding anticoagulation.

Ultrasound in Austere Environments.

Ultrasonography is a noninvasive, reliable, repeatable, and inexpensive technology that has dramatically changed the practice of medicine. The clinical use of portable ultrasound devices has grown tremendously over the last 10 years in the fields of intensive care, emergency medicine, and anesthesiology. In this review we present the various ways that handheld portable ultrasound devices can be used in austere environments. The purpose of this review is to consider the wide-ranging applications for providers going into the austere environment, which include pulmonary, ocular, vascular, and trauma evaluations, the postdisaster setting, and the role of ultrasonography in tropical diseases. This review is not meant to be a comprehensive how-to guide for each study type, but an overview of some of the more common wilderness applications. This review also focuses on the limitation of each study type. The goal is to help wilderness medicine providers feel more comfortable incorporating ultrasonography as part of their tool kit when heading into austere environments.

Waldenstrom-associated anti-MAG paraprotein polyneuropathy with neurogenic tremor.

A 71-year-old female patient presented with a 14-year history of slowly progressive distal limb numbness, paraesthesia and reduced vibration perception, ataxic gait and intentional tremor. Examination revealed with a length-dependent sensory neuropathy. Nerve conduction studies showed a chronic sensorimotor inflammatory demyelinating polyneuropathy. Intravenous immunoglobulin treatment (on two occasions) proved ineffective. Serum electrophoresis showed increased monoclonal IgM with kappa light chains. Anti-myelin-associated glycoprotein (MAG) levels were extremely elevated, >70 000 BTU. Bone marrow biopsy revealed 15%-20% small B cells and positive MYD88 mutation, indicative of Waldenstrom macroglobulinaemia. A diagnosis of Waldenstrom-associated anti-MAG paraprotein neuropathy with intentional (neurogenic) tremor was made. Repeat nerve conduction study showed a severe sensory demyelinating neuropathy with no axonal lesion. Treatment with rituximab was given for 1 month with minimal improvement. Repeat anti-MAG levels dropped to 53 670 BTU, with minimal clinical improvement.

Developing new SrI2 and ß-D-fructopyranose-based metal-organic frameworks with nonlinear optical properties.

In the context of personalized medicine, there is a growing interest in materials bearing at the same time diagnostic and therapy functions. This article reports a cheap and easily reproducible procedure to obtain materials with a high potential for these applications. Three new strontium iodide-fructose-based metal-organic frameworks with formulae [Sr(C6H12O6)2]I2, [Sr2(C6H12O6)3(H2O)3]I4·0.5H2O and [Sr(C6H12O6)(H2O)3I]I differing in stoichiometry, symmetry and crystal packing, were obtained and characterized by X-ray diffraction. Bulk quantum simulations show that both the ions and the sugar are crucial in determining the predicted nonlinear response; also, the relative arrangement of various functional groups in the unit cell plays a role in the computed optical properties. Small fragments of the three compounds were selected for in vacuo calculations, proving that the reduced dimensions of the particles have a great influence on the nonlinear optical response. Despite the similar chemical composition of the three compounds, second harmonic generation measurements and in crystal and in vacuo theoretical calculations agree that one of the compounds is a much more efficient second harmonic emitter than the other two, and is thus a suitable candidate for bio-sensor applications.

Synthesis, structure and non-linear optical properties of new isostructural ß-D-fructopyranose alkaline halide metal-organic frameworks: a theoretical and an experimental study.

In this work four metal-organic framework isomorphs, based on fructose and alkali-earth halogenides, were investigated to better understand the effect of the size of the cation and the different polarizability of the anion on the calculated hyperpolarizability and optical susceptibility, which are correlated to non-linear optical properties. The compounds were characterized by X-ray diffraction and the first hyperpolarizability and the second-order susceptibility were obtained from theoretical calculations. Furthermore, a new method to measure the second-harmonic (SH) efficiency on a small quantity of powder at different wavelengths of excitation was optimized and an attempt was made to assess the reduction of the SH intensity for small quantities of nano-crystals, in order to ascertain the possibility of applications in biological systems. The results of this work show that both the intrinsic nature of the anion and the induced dissociation of cations and anions by fructose play a role in the second-harmonic generating properties of such compounds.

Reversible and unilateral corticospinal tract disease secondary to autoimmune free-T3-thyrotoxicosis.

68-year-old female patient with no significant medical history presents with a 3-month history of progressive neurological symptoms, which began with left eye ptosis, blurred vision and non-painful jaw discomfort, followed by left spastic weakness and hyper-reflexia with positive Babinski and Hoffman signs. An elevated T3 level, a positive peroxidase and an antigraves antibody level led to an ultrasound, which confirmed a sub acute-chronic autoimmune thyroiditis. A nerve conduction studies/electromyogram showed normal motor and sensory velocity conduction with a small amplitude compound motor action potential, indicative of likely axonal damage. Following treatment with carbimazole, the neurological symptoms greatly improved. The authors concluded that the left pyramidal syndrome was secondary to autoimmune free T3-thyrotoxicosis.

An elusive ciliopathy: Joubert syndrome.

The police brought a 65-year-old female patient to the EADU after being found 'roaming the streets' in an apparent state of confusion. This was her third admission under the same circumstances during the last 3 years. Neurological examination revealed (1) cognitive impairment, (2) oculomotor apraxia, (3) abnormal cancellation of vestibular ocular reflex, (4) mild ataxia and (5) mild hypotonia. Renal function was abnormal and liver function was normal. No retinal disturbance was found. The head CT on admission was normal for stroke and the lumbar puncture was negative for encephalitis. Her brain MRI showed 'molar tooth sign', suggestive of Joubert syndrome, which was confirmed by genetic testing showing anomalous NPHP1 gene.

Forgetting to remember: hypoglycaemic encephalopathy.

A 37-year-old woman with a history of poorly controlled type 1 diabetes presented acutely with a decreased Glasgow Coma Scale and a diagnosis of hypoglycaemic brain injury. Her MRI highlighted bilateral hippocampi diffusion restriction and T2 hyperintensity. Clinically, she had a marked cognitive deficit, particularly of short-term, anterograde amnesia. She was managed conservatively and with intensive rehabilitation.

Partial interhemispheric disconnection syndrome (P-IHDS) secondary to Marchiafava-Bignami disease type B (MBD-B).

A 53-year-old man with a 35-year history of excessive alcohol intake presents to our neurology department with 4-year history of progressive neurocognitive deterioration and disconnection syndrome. MRI head demonstrates extensive demyelination of the corpus callosum (and of extracallosal sites as well), leading to a diagnosis of Marchiafava-Bignami disease. He was given treatment with vitamin B complex (including folate) and was assessed and managed by psychology, occupational therapy and physiotherapy with initial signs of improvement.

Park sleep: a non-motor dominant Parkinson's disease phenotype.

A 69-year-old man was evaluated in our neurology department, for a presumed diagnosis of 'night-time seizures'; however, this diagnosis was quickly dismissed after the patient (and his wife) described how he 'acted out' and talked throughout his dreams, without any seizure-like activity. This problem had been present for ∼10 years. An EEG ruled out epilepsy. The patient also described a 10-year history of constipation, loss of smell and 'frequent collapses'. These symptoms fit in with the recently published criteria of 'prodromal Parkinson's Disease' and prompted a formal assessment for Parkinson's disease (PD). He had no tremor. A subtle festinating gait pattern and a 2-finger tremor in the right hand were noted. The diagnosis of PD was confirmed by a dopamine transporter scan. Clinically, this is one-Park sleep: rapid eye movement sleep behaviour disorder subtype-of 7 different non-motor dominant PD phenotypes recently described.

Progressive bilateral ophthalmoparesis--a case of simultaneous autoimmunity: balancing Graves' ophthalmoparesis and ocular myasthenia.

A 44-year-old woman with no medical history presented with a 1-year history of horizontal diplopia, bilateral exophthalmos and progressive asymmetrical ophthalmoparesis, with no pupillary dysfunction or ptosis. Within 3 months of her initial presentation, she noticed paresis of right eye abduction, followed after 1 month with paresis of left eye abduction. Initial investigations revealed positive antiperoxidase antibodies for Graves' disease and positive AChR for myasthenia gravis. MRI of the brain showed increased intensity in bilateral inferior rectus muscles and CT of the chest showed thymic hyperplasia. Treatment with carbimazole and pyridostigmine was started, with complete resolution after 1 month.

A deceitful stroke, a hidden tumour.

A 41-year-old woman with malignant left middle cerebral artery infarction underwent an immediate decompressive craniectomy, obtaining good recovery, both clinically and radiologically. However, approximately 6 months after a successful discharge, the patient returned with gradual memory deterioration, dysarthria and progressively worsening headaches. Subsequent CT and MRI of the brain revealed a solid malignancy located in the same region as the extensive infarction. Following this finding, she underwent surgical debulking of the tumour and follow-up radiotherapy, with good progression of symptoms and overall good outcome.

A model study on the absorbed dose of radiation following respiratory intake of 238U3O8 aerosols.

Aerosols of depleted uranium oxides, formed upon high-energy impact of shells on hard targets during military operations, are able to disperse, reach the alveolar region of the lungs and be absorbed and distributed throughout various parts of the body. The absorbed particles are subjected to clearance in the upper respiratory tract, distribution to other body districts, dissolution and excretion. While the soluble forms of uranium are known to deliver a small dose of radiation to the body due to their homogeneous distribution and the low specific activity of (238)U, ceramic particles exhibit a low dissolution rate and irradiate a limited volume of tissue for a long time with alpha particles with an energy of 4.267 MeV. The extent of the irradiated tissues depends on the radius of the particles and the total intake of uranium oxides. For the measured intake of U3O8 of a war veteran (15.51 µg) the number of particles ranges from 5.56×10(4) to 6.95×10(6) for sizes of 0.4-2.0 µm. Modelling the distribution of the particles between two compartments of the body, the averaged dose absorbed in 20 y by tissues surrounding the particles and within the range of the alpha particles varies from 6.8 mGy to 0.85 Gy for lungs and 8.1 mGy to 1.0 Gy for the lymph nodes, respectively. Correspondingly, due to the clearance and redistribution, the mass irradiated by 2.0-µm particles falls in 20 y from 6.06 mg to 0.94 µg in the lungs and grows from 0 to 1.0 mg in the lymph nodes. The estimated rate of formation of hydroxyl radicals upon radiolysis of water in the lungs and lymph nodes is 5.17×10(4) d(-1) per cell after 1 y.

On the curvature in logarithmic plots of rate coefficients for chemical reactions.

In terms of the reduced potential energy barrier ζ = ΔuTS/kT, the rate coefficients for chemical reactions are usually expressed as proportional to e-ζ. The coupling between vibrational modes of the medium to the reaction coordinate leads to a proportionality of the regularized gamma function of Euler Q(a,ζ) = Γ(a,ζ)/Γ(a), with a being the number of modes coupled to the reaction coordinate. In this work, the experimental rate coefficients at various temperatures for several chemical reactions were fitted to the theoretical expression in terms of Q(a,ζ) to determine the extent of its validity and generality. The new expression affords lower deviations from the experimental points in 29 cases out of 38 and it accounts for the curvature in the logarithmic plots of rate coefficients versus inverse temperature. In the absence of tunneling, conventional theories predict the curvature of these plots to be identically zero.

A stationary-wave model of enzyme catalysis.

An expression for the external force driving a system of two coupled oscillators in the condensed phase was derived in the frame of the Debye theory of solids. The time dependence and amplitude of the force is determined by the size of the cell embedding the coupled oscillators and its Debye temperature (theta(D)). The dynamics of the driven system of oscillators were followed in the two regimes of (a) low theta(D) and cell diameter, as a model of liquid water, and (b) large theta(D) and cell diameter, as a model of the core of a protein. The response in potential energy of the reference oscillator was computed for all possible values of the internal parameters of the system under investigation. For protein cores, the region in the parameter space of high maximum potential energy of the reference oscillator is considerably extended with respect to the corresponding simulation for water.

Desequilibrio esfuerzo-recompensa y estado de malestar mental en trabajadores de Servicios de Salud en Chile / Effort-reward unbalance and mental uneasiness state in health services workers in Chile

El presente estudio es de tipo exploratorio y aborda la asociación entre las dimensiones del modelo de estrés laboral (Effort Reward Imbalance, DER), y el modelo de salud mental (General Health Questionnaire, GHQ-28). Se basa en entrevistas y encuestas realizadas a 68 trabajadores del sector salud en 3 lugares de Santiago, Chile (un hospital privado, un hospital público y un consultorio de atención primaria). Los participantes incluyen auxiliares de enfermería, técnicos paramédicos y personal administrativo de varios departamentos. Se encontró asociaciones positivas entre el mal estado de salud mental y la presencia de estrés laboral.

This study explored the association between dimensions of a job-stress model, Effort-Reward Imbalance (ERI), and a mental health model, the General Health Questionnaire (GHQ-28). The exploratory study was based on interviews and self-response questionnaires given to 68 health care workers at three worksites in Santiago, Chile (a large public hospital, a large private hospital, and a primary care clinic). The participants included nursing assistants, technicians, and administrative staff from various departments. Positive associations were found between bad mental health and job stress.