Phototransduction in Anuran Green Rods: Origins of Extra-Sensitivity

Green rods (GRs) represent a unique type of photoreceptor to be found in the retinas of anuran amphibians. These cells harbor a cone-specific blue-sensitive visual pigment but exhibit morphology of the outer segment typical for classic red rods (RRs), which makes them a perspective model object for studying cone–rod transmutation. In the present study, we performed detailed electrophysiological examination of the light sensitivity, response kinetics and parameters of discrete and continuous dark noise in GRs of the two anuran species: cane toad and marsh frog. Our results confirm that anuran GRs are highly specialized nocturnal vision receptors. Moreover, their rate of phototransduction quenching appeared to be about two-times slower than in RRs, which makes them even more efficient single photon detectors. The operating intensity ranges for two rod types widely overlap supposedly allowing amphibians to discriminate colors in the scotopic region. Unexpectedly for typical cone pigments but in line with some previous reports, the spontaneous isomerization rate of the GR visual pigment was found to be the same as for rhodopsin of RRs. Thus, our results expand the knowledge on anuran GRs and show that these are even more specialized single photon catchers than RRs, which allows us to assign them a status of “super-rods”.

The role of ultrasonography in diagnosing hourglass-like fascicular constriction(s) of the anterior interosseous nerve

Background In the past, the diagnosis of hourglass-like fascicular constriction(s) of the anterior interosseous nerve mostly depended on electrophysiological examination, by which the location could not be diagnosed. There are few studies on the evaluation of hourglass-like fascicular constriction(s) by ultrasonography. Purpose To evaluate the role of ultrasonography in the diagnosis of hourglass-like fascicular constriction(s) of the anterior interosseous nerve. Material and Methods A retrospective analysis of 12 patients with hourglass-like fascicular constriction(s) of the anterior interosseous nerve was carried out, and the characteristics of the high-frequency ultrasonographic images were summarized and compared with surgical exploration. Results The 12 cases of hourglass-like fascicular constriction(s) of the anterior interosseous nerve were all located in the median nerve of the distal upper arm, including nine cases of single hourglass-like fascicular constriction and three cases of multiple hourglass-like fascicular constrictions. High-frequency ultrasonography can accurately locate the hourglass-like fascicular constriction(s) of the anterior interosseous nerve and the extent of neuropathy. The ultrasonographic images of hourglass-like fascicular constriction(s) of the anterior interosseous nerve showed single or multiple hourglass-like change(s) in the median nerve of the distal upper arm. The nerve fascicles on both sides of the affected nerve with hourglass-like change thickened. Conclusions High-frequency ultrasonography could be a reliable, convenient, and non-invasive diagnostic imaging method for hourglass-like fascicular constriction(s) of the anterior interosseous nerve.

Post-coronavirus disease 2019 polyneuropathy with significant response to immunoglobulin therapy: a case report

Background The symptoms of coronavirus disease 2019, caused by the novel severe acute respiratory syndrome coronavirus 2, were originally assumed to be mainly respiratory. With increasing knowledge, however, it turned out that the spectrum of complaints varies broadly with age and concomitant diseases. While many neurological symptoms were reported in the context of the disease, ranging from permanent fatigue to recurrent headaches and concentration disturbance, treatment approaches are still in development. This case discusses a possible treatment approach with immunoglobulin therapy and its outcomes. Case presentation We present the case of a 56-year-old Caucasian female patient who, following coronavirus disease 2019, developed peripheral sensory and autonomic disturbances that fell within subacute demyelinating neuropathy. Because a significant improvement in symptoms as well as in the results of clinical and electrophysiological examination was reported after immunoglobulin therapy, long-term therapy does not appear to be necessary. Conclusion Given the significant subjective and objective improvement reported, this case provides additional evidence that immunoglobulin therapy can be considered in post-coronavirus disease 2019 syndrome.

Case Report: Successful Outcome for Refractory Diabetic Peripheral Neuropathy in Patients With Ultrasound-Guided Injection Treatment

Diabetic peripheral neuropathy is the most prevalent chronic complication of diabetes and is based on sensory and autonomic nerve symptoms. Generally, intensive glucose control and nerve nourishment are the main treatments. However, it is difficult to improve the symptoms for some patients; such cases are defined as refractory diabetic peripheral neuropathy (RDPN). In this paper, we present five patients treated with saline and mecobalamin by ultrasound-guided injection. The Visual Analog Scale and Toronto Clinical Scoring System were used to evaluate the symptoms, and the neuro-ultrasound scoring system and electrophysiological severity scale were evaluated by ultrasound and electrophysiological examination. In brief, ultrasound-guided hydrodissection may be a safe way to treat RDPN.

Electrophysiological features of Guillain-Barré syndrome in Mongolian adult patients

The Guillain-Barré syndrome (GBS) is a rare but severe disorder that affects peripheral nerves and is classified into several subtypes based on clinical presentation and electrophysiological abnormalities. Incidence and predominant subtypes of GBS differ geographically. The diagnosis is made upon clinical features and confirmed by nerve conduction studies (NCSs) which can differentiate subtypes such as demyelinated and axonal. Demyelinating subtypes in Europe and North America and axonal subtypes in Asia are predominant. Electrophysiological subtypes have not been determined in Mongolia. Therefore, we aimed to determine common electrophysiological subtypes of Guillain-Barré syndrome in Mongolia. In our study, 75 patients referred to Reflex Neurological Clinic between 2016 and 2019 were retrospectively reviewed. After excluding the cases by the criteria, patients were classified as demyelinating, axonal, normal and equivocal subtypes based on Hadden criteria. We compared the electrophysiological features of axonal and demyelinating subtypes. SPSS-23 was used for statistical analysis. The results are expressed in averages (standard deviations) and percentages (numbers). The difference between the mean and the group of variables was calculated using the T-test and the Chi-square test. Patients were 44% male (33), and the mean age was 46.4±15.1. There was no significant association between seasonal factors and electrophysiological subtypes. Among 75 patients with Guillain-Barré syndrome, a nerve conduction study was performed in the first week on 36% of patients, 33.3% in the 2nd week, and others in the 3rd-4th week after symptom onset. Electrophysiology subtypes were classified as demyelinating (65.3%), axonal (20%), within the normal range (5.4%) and equivocal (9.3%) based on Hadden criteria. The absence of F-waves on electrophysiological examination was higher in patients within 14 days of the disease onset, whereas non-sensory changes were higher in patients after 14 days. We conclude that acute inflammatory demyelinating neuropathy (AIDP) was the most frequent subtype of GBS in Mongolia.

Case Report: Wide-to-Narrow QRS Tachycardia in a 3-Month-Old Infant

Introduction: It is rare to find that wide QRS tachycardia automatically changes to narrow QRS tachycardia, and it is more difficult to clarify the mechanism.Case Report: A 3-month-old infant with recurrent paroxysmal supraventricular tachycardia underwent transesophageal cardiac electrophysiological examination. The wide QRS tachycardia was induced by atrial RS2 stimulation, and it soon changed to narrow QRS tachycardia automatically. By the accurate measurement of esophageal lead, it was found that the electrocardiogram changes completely conform to Coumel law. The mechanism of wide and narrow QRS tachycardia was orthodromic atrioventricular reentrant tachycardia with or without ipsilateral functional bundle branch block, and the accessory pathway was defined as the left free wall-concealed accessory pathway.Conclusion: Transesophageal cardiac electrophysiological examination can reveal some special electrophysiological phenomena, and its non-invasive nature is especially suitable for infants.

Guillain Barre Syndrome associated with COVID-19 Infection: A Case Report

Coronavirus Disease has become a global pandemic after its emergence at the end of 2019 as a cluster of pneumonia. Apart from respiratory symptoms, neurologic complications are also common, mostly in hospitalized patients. More than 80 percent of patients have neurological symptoms during their disease course of which most common is encephalopathy. However, data on neurological complications like Guillain-Barré syndrome associated with coronavirus-2019 are scarce. Here, we report a case of a 64-years-old female patient with typical clinical and electrophysiological manifestations of Acute motor axonal neuropathy variant, who was reported positive with polymerase chain reaction for severe acute respiratory syndrome coronavirus-2, 13 days before the onset of acute bilateral weakness of extremities, areflexia, and normal sensory examination. Cerebrospinal fluid and electrophysiological examination were also suggestive. The neurological symptoms improved during treatment with immunoglobulins. Quick recognition of symptoms and diagnosis is important in the management of Guillain-Barré syndrome associated with coronavirus-2019.

Kinesio taping as an alternative treatment for manual laborers with carpal tunnel syndrome: A double-blind randomized clinical trial

BACKGROUND: Carpal tunnel syndrome (CTS) is one of the most common forms of peripheral neuropathies due to median nerve compression. Occupational factors, such as repetitive hand motions are believed to be associated with this condition. OBJECTIVE: This clinical trial assessed the effect of Kinesio taping (KT) of hand flexor muscles on the management of mild to moderate CTS in Iranian manual laborers. METHODS: Thirty manual laborers with mild to moderate CTS participated in this clinical trial. They were assigned to an intervention or a control group. The treatment consisted of a 2-week KT followed by a 4-week follow-up. The control group received sham KT without tension applied. Boston Carpal Tunnel Questionnaire scores, pinch and grip force tests, and electrophysiological examination of the median nerve were performed for each participant at baseline, 24 to 48 hours, and two to four weeks of follow-up. The statistical analysis of variance was performed five times for all participants, comparing differences in the data within and between the two groups. RESULTS: The baseline assessment revealed no inter-group differences in the clinical outcomes (P⩽ 0.05). Comparisons of the changes in the electro-physiological and functional variables indicated significantly greater improvement in the KT group than in the sham counterpart (P< 0.05). No statically significant improvement was evident by the electrodiagnostic criteria in the sham-KT group (P⩽ 0.05). CONCLUSIONS: KT is an effective, safe, reliable, and conservative therapeutic choice for the management of patients with CTS. The treatment does not restrict the daily activities of patients nor has it any side effects.