Sensitivity to mechanical stimuli and the role of general sensory and perceptual processes in heartbeat detection

Sensitivity to heartbeat sensations is commonly assessed using tasks that require individuals to judge the simultaneity of heartbeats and tones. In two experiments, we investigated the suitability of this paradigm for examining cardioception. In the first experiment, participants judged the simultaneity of near–threshold vibrations and suprathreshold tones. Precision in judging vibration–tone simultaneity was directly related to the detectability of the mechanical stimuli, thereby supporting use of the simultaneity paradigm to assess heartbeat detection. In the second experiment, we examined the influences of sensitivity to mechanical stimuli and the ability to make intermodality simultaneity judgments on the precision of heartbeat detection. We measured participants' vibrotactile thresholds, precision in judging light–tone simultaneity, and precision in judging heartbeat–tone simultaneity. The ability to judge the simultaneity of lights and tones accounted for 24.3% of the variance in precision of heartbeat detection, and mechanical sensitivity accounted for a further 8.5%.     

Processing of binaural stimuli by cat superior olivary complex neurons

Summary A method was developed to record stereotactically from the cat Superior Olivary Complex (SOC) using glass micropipettes. Sound stimulation was given through a closed system that permitted independent variation of interaural time (time) and intensity (int) differences. The most common binaural units found (n = 34) were ipsilateral excitatory, contralateral inhibitory (EI¹), cells of the Lateral Superior Olive (LSO). Some Medial Superior Olive (MSO) cells and presumed MSO ascending afferents were found but, as noted by other authors, we found it difficult to obtain single unit recordings from this nucleus. The LSO EI cells were mostly sensitive to higher frequencies and showed Peristimulus Time Histograms (PSTHs) consisting of a sharp On response followed by a plateau when stimulated with Best Frequency (BF) tone bursts or noise bursts. This On response was sensitive to time and int such that ipsilateral time lead or intensity increase resulted in a stronger response. The response reached a minimum around zero time or int. No sharp peaks or dips were seen in the physiological range needed for localization, instead the response increased with increasing ipsilateral lead or intensity to the maximum values tested (2048 s time, 30 dB int). In the physiological range the time and int response were complementary (both increasing response as ipsilaterality was increased). Provided enough sound energy in the unit's sensitive region was present, the same time curves were produced when BF tone bursts, masked tone bursts, sharp onset tone bursts or noise bursts were used. Changing the time of the carrier of the tone burst alone had no effect (except for one cell with a BF of 560 Hz), only the relative time of arrival of the stimulus envelope seemed to be important. In contrast to these LSO EI cells MSO-type units showed EI or EE predominantly low frequency phase-locked responses. When stimulated with interaurally phase shifted (pha) BF tones the unit response was a cyclic function of pha. Some cells (all that were tested, n = 6 including the 560 Hz LSO EI cell) showed these cyclic responses when stimulated with noise bursts or non-BF tones. However, these characteristic delays were not necessarily in the physiological range, i.e. we could find no evidence that these units were responding to time/pha values corresponding to a particular sound source direction. In both LSO and MSO it seems that integration of information higher in the CNS from a population of these cells is necessary for unambiguous coding of sound source direction. The time intensity trading ratios measured in two MSO type cells (11 and 26 /dB) were clearly different to those measured in LSO EI cells (n = 6, 99–550 s/dB). These ratios correspond approximately to those of the psychophysical time and int images measured by Hafter and Jeffress (1968).Supported by the Deutsche Forschungsgemeinschaft (SFB 45)     

U波倒置40例临床分析

U波倒置40例,其中孤立性U倒16例(40％),复合性U倒24例(60％)。U波倒置常见于左心前导联V_5V_6,呈现左室肥厚及负荷加重,心电图示“左室劳损”型。U波倒置严重合并症,除心力衰竭外,还有急性心肌梗塞和室性期前收缩。笔者认为,通过本文分析,UV_5倒置对临床诊断冠心病,高血压等是有价值的。     

Effects of a single bout of short-duration high-intensity and long-duration low-intensity exercise on insulin resistance and adiponectin/leptin ratio

ObjectivesModerate-intensity exercise improves insulin sensitivity, which may depend on the intensity, duration, and frequency of exercise. We examined the effects of a single bout of short-duration high-intensity exercise (HIE) and long-duration lowintensity exercise (LIE) on insulin sensitivity and the adiponectin/leptin ratio in individuals with different body mass indices (BMIs) who do not exercise regularly.MethodsWe enrolled 42 healthy volunteers aged 20–64 years and divided them into two groups based on BMI: BMI <24 kg/m² and BMI ≥27 kg/m². They were randomly assigned to either the short-duration (20 min) HIE (70%–80% heart rate reserve, HRR) or long-duration (60 min) LIE training groups (30%–40% HRR). Glucose, insulin, adiponectin, and leptin levels were assessed before training and at 0, 30, 60, and 120 min after training.ResultsWe finally analyzed 27 normal weight and 9 obese individuals. No significant differences were observed in the baseline information of both BMI groups. Homeostatic model assessment for insulin resistance significantly improved for both exercise patterns in the normal weight group and for the HIE pattern in the obese group (P < 0.01), whereas the adiponectin/leptin ratio increased significantly only among normal weight participants with the LIE intervention.ConclusionBoth exercise patterns in BMI <24 kg/m² and BMI ≥27 kg/m² benefit on insulin resistance. Therefore, people can choose the way they can fit to improve insulin resistance both short-duration high-intensity exercise and long-duration low-intensity exercise.     

An Overview of the Treatment Options Used for the Management of COVID-19 in Pakistan: Retrospective Observational Study

BackgroundSince the first reports of COVID-19 infection, the foremost requirement has been to identify a treatment regimen that not only fights the causative agent but also controls the associated complications of the infection. Due to the time-consuming process of drug discovery, physicians have used readily available drugs and therapies for treatment of infections to minimize the death toll.ObjectiveThe aim of this study is to provide a snapshot analysis of the major drugs used in a cohort of 1562 Pakistani patients during the period from May to July 2020, when the first wave of COVID-19 peaked in Pakistan.MethodsA retrospective observational study was performed to provide an overview of the major drugs used in a cohort of 1562 patients with COVID-19 admitted to the four major tertiary-care hospitals in the Rawalpindi-Islamabad region of Pakistan during the peak of the first wave of COVID-19 in the country (May-July 2020).ResultsAntibiotics were the most common choice out of all the therapies employed, and they were used as first line of treatment for COVID-19. Azithromycin was the most prescribed drug for treatment. No monthly trend was observed in the choice of antibiotics, and these drugs appeared to be a random but favored choice throughout the months of the study. It was also noted that even antibiotics used for multidrug resistant infections were prescribed irrespective of the severity or progression of the infection. The results of the analysis are alarming, as this approach may lead to antibiotic resistance and complications in immunocompromised patients with COVID-19. A total of 1562 patients (1064 male, 68.1%, and 498 female, 31.9%) with a mean age of 47.35 years (SD 17.03) were included in the study. The highest frequency of patient hospitalizations occurred in June (846/1562, 54.2%).ConclusionsGuidelines for a targeted treatment regime are needed to control related complications and to limit the misuse of antibiotics in the management of COVID-19.     

肝脏局灶性小占位的磁共振信号强度比与病灶性质的相关性

目的 计算肝细胞癌、肝转移瘤、肝脏海绵状血管瘤和肝囊肿的病灶／肝脏磁共振信号强度比（SIR）,并评价其与病灶性质的关系。方法 随机选择经确诊的肝细胞癌、肝转移瘤、肝海绵状血管瘤和肝囊肿病例共92例（148个病灶）行前瞻性磁共振成像（0．5T）研究。计算4种病灶的SIR,并进行统计学分析。结果 在T1W图像上,肝海绵状血管瘤与恶性肿瘤的SIR值间差异无显著性（t=1.799,P=0.075);质子加权像上,良恶性肿瘤的SIR之间无统计学意义（t=0.691,P=0.491);T2WI上,良性病变的SIR显著高于恶性肿瘤（P＜0．01）,且4种病变的SIR值与回波时间（TE）之间均存在线性正向相关关系。结论 在T2WI个测得的SIR可用于区分肝脏占位性病灶的性质。     

心肌多普勒组织显像与心肌增厚率相关分析

目的：研究脉冲多普勒组织显像评价室壁运动的可行性。方法：对19例研究对象左室基底段心肌进行脉冲多普勒组织显像并测量最大收缩速度及心肌收缩平均加速度和在同一部位的M-mode运动轨迹上测量心肌增厚率,对其进行相关回归分析。结果：心肌脉冲多普勒显像的最大收缩速度与M-Mode测量的心肌增厚率呈中度相关（r=0.55,P＜0.05),脉冲多普勒组织显像的心肌收缩平均加速度与M-mode的心肌增厚率呈中度相关（r=0.56,P＜0.05)。结论：脉冲多普勒组织显像显示的心肌最大收缩速度和心肌收缩平均加速度可作为评价室壁节段运动的指标。     

肾盂肾下盏夹角对结石清除率的影响

目的：观察肾盂肾下盏夹角及结石大小对结石排净率的影响。方法：选择68例肾下盏结石患者,通过IVU影像,测量夹角与结石直径,并经ESWL治疗,随访2月,观察结石排空情况。结果：68例患者,结石完全排出42例,总的排石排空率为61．7％。结论：提示肾盂肾下盏夹角,结石直径对结石排净率有重要影响。     

Role of shear wave elastography measured in the flaccid state in predicting arteriogenic erectile dysfunction

The gold-standard method for diagnosing arteriogenic erectile dysfunction (AED) is the penile Doppler ultrasonography. We proposed a novel method for predicting AED using ultrasonic shear wave elastography (SWE) considering that the former was invasive and variable. A total of 98 male patients were enrolled in our study, referred for ED between December 2018 and October 2020. For comparison, we also included 42 volunteers from the Healthy Physical Examination Center of our hospital. The Penile Doppler Ultrasonography (PDU) and SWE were performed for all patients with the intracavernosal injection (ICI). We named three groups as AED group, nonvascular ED group and healthy controls group. No statistically significant differences were found among the three groups in terms of demographic and clinical characteristics. There were no significant differences in IIEF-5 between AED and nonvascular ED. A significant (r = 0.642, p < 0.0001) positive correlation between flaccid and erectile SWE was observed. With a cut-off value of 13.45 KPa, the area under curve, specificity, and sensitivity of the SWE values under the flaccid state in distinguishing AED from healthy subjects were 0.867, 0.786 and 0.896 respectively. The SWE value in the flaccid state can distinguish the AED from healthy subjects.     

Can low intensity pulsed ultrasound (LIPUS) be used as an alternative to revision surgery for patients with non-unions following fracture fixation?

BackgroundNon-union is a significant complication of fracture fixation surgery, and can negatively impact a patient’s quality of life. Low intensity pulsed ultrasound (LIPUS) has been used to treat delayed or non-unions previously in the literature. The aim of this study was to determine the success rate of LIPUS treatment in patients with chronic fracture non-unions, and to establish the effect of systemic or local factors on its success.MethodsThis was a retrospective, observational study which included all patients undergoing LIPUS treatment in a single institution. Patients deemed suitable for LIPUS underwent treatment for a period of 6 months from initiation. They were followed up with sequential radiographs to assess union at intervals of 6 weeks, 3 months, 6 months and 1 year. LIPUS treatment was considered to be successful when patients achieved clinical and radiological union, without the need for revision surgery.ResultsA total of 46 patients were included in the study; 8 were lost to follow – up, leaving 38 patients for the final analysis. The mean age of patients was 47.03 ± 19.7 with a male to female ratio of 1.2:1. Union was achieved in 57.89%; the rest underwent revision surgery. There was no significant association between outcomes after LIPUS treatment and patients’ age, gender, smoking status or type of non-union. Patients with a small inter-fragment bone gap were more likely to have a successful outcome after LIPUS (p = 0.041). Time to treatment did not have a statistically significant impact on outcomes after LIPUS. Interestingly, all 6 patients with diabetes in the study managed to achieve union after LIPUS.ConclusionsThis study demonstrates that LIPUS is not successful in a large proportion of patients with established fracture non-unions. However, it does represent a low risk treatment modality as an alternative to revision surgery, especially for patients with diabetes who have a small inter – fragment bone gap. More research in the form of large randomised controlled trials needs to be carried out to further assess the role of LIPUS in the treatment of non-unions.