The face of postural tachycardia syndrome - insights from a large cross-sectional online community-based survey.

BACKGROUND: Patients with postural tachycardia syndrome (POTS) experience chronic symptoms of orthostatic intolerance. There are minimal data detailing the demographics, clinical features and clinical course of this condition. This online, community-based survey highlights patients' experience with POTS. It consists of the largest sample of POTS patients reported to date. OBJECTIVES: To describe the demographics, past medical history, medications, treatments and diagnostic journey for patients living with POTS. METHODS: Postural tachycardia syndrome patients completed an online, community-based, cross-sectional survey. Participants were excluded if they had not received a diagnosis of POTS from a physician. The questions focused on the patient experience and journey, rather than physiological responses. RESULTS: The final analysis included 4835 participants. POTS predominantly affects white (93%) females (94%) of childbearing age, with approximately half developing symptoms in adolescence (mode 14 years). POTS is a chronic multisystem disorder involving a broad array of symptoms, with many patients diagnosed with comorbidities in addition to POTS. POTS patients often experience lengthy delays [median (interquartile range) 24 (6-72) months] and misdiagnosis, but the diagnostic delay is improving. POTS patients can present with a myriad of symptoms most commonly including lightheadedness (99%), tachycardia (97%), presyncope (94%), headache (94%) and difficulty concentrating (94%). CONCLUSIONS: These data provide important insights into the background, clinical features and diagnostic journey of patients suffering from POTS. These data should serve as an essential step for moving forward with future studies aimed at early and accurate diagnoses of these patients leading to appropriate treatments for their symptoms.

Cell proliferation in the cochlear nucleus following acoustic trauma in rat.

Our previous studies have suggested that surgical lesions of the rat cochlea induce cell proliferation in the cochlear nucleus (CN) that may be related to neurogenesis. The aim of the present study was to further investigate the nature of cell proliferation in the CN, following acoustic trauma that has previously been shown to induce tinnitus in rats. Rats were subjected either to a unilateral acoustic trauma (16-kHz pure tone, 115dB for 1h under anesthesia) or a sham procedure. Bromodeoxyuridine (BrdU) immunohistochemistry was used to measure cell proliferation and newborn cell survival; an antibody to interleukin-6 was used to investigate inflammatory responses; and double immunolabeling for BrdU and Ki-67, BrdU and CD-11b, and BrdU and doublecortin (DCX), was used to investigate the origin of the proliferating cells. There was a time-dependent increase in the number of BrdU(+ve) cells in the CN following acoustic trauma; however, the number of BrdU(+ve) cells that survived was comparable to that of control animals at 4 weeks post-trauma. Cell proliferation was unlikely to be due to proliferating inflammatory cells as a result of a trauma-induced inflammatory response as the IL-6 expression level was comparable between sham and exposed groups. Immunolabeling revealed the BrdU(+ve) cells to co-express Ki-67 and DCX, but not CD-11b. However, there was no difference in DCX expression between sham and exposed animals. The results suggest that DCX-expressing cells in the CN may proliferate in response to acoustic trauma; however, the proportion of cells proliferating and the survival rate of the newborn cells may not support functional neurogenesis in the CN.

Acoustic trauma that can cause tinnitus impairs impulsive control but not performance accuracy in the 5-choice serial reaction time task in rats.

Although tinnitus is an auditory disorder, it is often associated with attentional and emotional problems. Functional neuroimaging studies in humans have revealed that the hippocampus, amygdala and anterior cingulate, areas of the brain involved in emotion, attention and spatial processing, are also involved in auditory memory and tinnitus perception. However, few studies of tinnitus-evoked emotional and cognitive changes have been reported using animal models of tinnitus. In the present study, we investigated whether acoustic trauma that could cause tinnitus would affect attention and impulsivity in rats. Eight male Wistar rats were exposed to unilateral acoustic trauma (110 dB, 16 kHz for 1 h under anaesthesia) and eight rats underwent the same anaesthesia without acoustic trauma. Tinnitus was tested in noise-exposed rats using a frequency-specific shift in a discrimination function with a conditioned lick suppression paradigm. At 4 months after the noise exposure, the rats were tested in a 5-choice serial reaction time task. The behavioural procedure involved training the rats to discriminate a brief visual stimulus presented randomly in one of the five spatial locations and responding by poking its nose through the illuminated hole and collecting a food pellet from the magazine. While all of the animals performed equally well in making correct responses, the animals exposed to acoustic trauma made significantly more premature responses. The results suggest that rats exposed to acoustic trauma and some of which have chronic tinnitus are impaired in impulsive control, but not performance accuracy.

Effects of two sesquiterpene lactones isolated fromArtemisia annua on physiology ofLemna minor.

The effects of artemisinin and arteannuic acid extracted fromArtemisia annua on the physiology ofLemna minor were evaluated. Changes in frond production, growth, dry weight, and chlorophyll content ofL. minor were determined. Photosynthesis and respiration were evaluated with a differential respirometer. Artemisinin (5 µM) inhibitedL. minor frond production and dry weight 82 and 83%, relative to methanol controls. Chlorophyll content was reduced 44% by artemisinin (2.5 µM). Arteannuic acid (10 µM) was less active, inhibiting frond production 61% and reducing chlorophyll content 66% at 5 µM. Artemisinin (1 µM) reducedL. minor photosynthesis 30% and 2.5 µM reduced respiration 39%. Arteannuic acid had no significant effect on photosynthesis or respiration at the levels tested.