Learning postural tasks in hemiparetic patients with lesions of left versus right hemisphere

There are a number of studies concerning difference of postural control following left or right hemisphere lesions. Few studies, however, compare the role of the right and left hemisphere in learning new postural tasks. This study aimed to address this question. Twenty patients with hemiparesis after ischemic stroke in the middle cerebral artery territory (11 with a right and 9 with a left hemispheric lesion) were investigated. All subjects were trained using two different tasks during ten training sessions. In both tasks, the subjects stood on a force platform and were taught to change the position of the center of pressure (COP) presented as a cursor on a monitor screen in front of the patient. The subjects were instructed to align the COP with the target and then move the target by shifting the COP in the indicated direction. In the “Balls” task, the position of the target (a ball) varied randomly, so the subject had to learn a general strategy of voluntary COP control. In “Bricks”, the subject always had to move the target in a single direction (downward) from the top to the bottom of the screen, so that a precise postural coordination had to be learned. The number of correctly performed trials for a session was scored. The task performance and its rate were analyzed and compared with respect to the lesion lateralization between two patient groups. The voluntary control of the COP position and learning course were initially impaired in all groups of patients in both tasks. In “Balls”, there were no differences between the two groups of patients. In contrast, in “Bricks”, there was a greater initial deficit in patients with right hemisphere lesions, while the rate of postural learning and the final performance level did not differ between the groups. With a lower initial deficit and similar rate of learning, the maximal level of the task performance was reached earlier (on the 5th day of training) in patients with left hemisphere lesions. This group stopped improving its performance during follow-up training. The results suggest that the motor structures of the right hemisphere are more involved in the precise control of COP trajectory, but not in learning. There is no difference between hemispheres in the initial performance and learning of the general strategy of voluntary COP control. Possibly, the control of specific COP trajectory needs more sensory feedback that is associated with greater involvement of the right hemisphere. This might be a reason for the greater initial impairment of this task after lesions in the right hemisphere.     

Modified oxygen mask to induce target levels of hyperoxia and hypercarbia during radiotherapy: a more effective alternative to carbogen

PURPOSE: Carbogen has long been under investigation as an adjuvant to radiotherapy of tumors. A major factor confounding its evaluation is its inconsistency in raising blood partial pressure of CO(2) (pCO(2)). We investigated whether a new partial rebreathing method would provide better control of pCO(2) than carbogen. METHODS AND MATERIALS: We compared the efficacy of each method in 10 healthy volunteers. Volunteers breathed 1.5, 3 and 5% carbogen in 5-min stages via the usual non-rebreathing circuit. All the volunteers then breathed 100% O(2) through a commercial sequential gas delivery (SGD) circuit modified by attaching a reservoir to its exhalation port. Hypercarbia was induced by step reductions in oxygen flow to the SGD circuit. We monitored minute ventilation and end-tidal pCO(2) (ETpCO(2)) as a surrogate for its arterial value. RESULTS: Inhalation of 1.5 and 3% carbogen did not increase ETpCO(2) from baseline (40 +/- 1.5 mmHg); 5% carbogen increased ETpCO(2) to 45 +/- 1.6 mmHg (p < 0.001). With the SGD circuit, reducing O(2) flow to 4.3 +/- 0.7 l/min increased ETpCO(2) in all subjects from 41 +/- 2.0 mmHg (baseline) to 46 +/- 2.1 mmHg (p < 0.001). Voluntary hyperventilation reduced ETpCO(2) with 5% carbogen but not with SGD (p = 0.379). CONCLUSIONS: We confirm previous observations that carbogen inhalation does not result in a predictable rise in ETpCO(2) and suggest that a precise and stable target ETpCO(2) can instead be induced by simply controlling O(2) flow into a modified SGD circuit. We hoped that the reliable control of pCO(2) will enable studies that address first, the efficacy of raising ETpCO(2) on specific tumor blood flow, and eventually, its benefit as an adjuvant to radiotherapy.     

Low incidence of adhesion-related bowel obstruction after laparoscopic colorectal surgery

BACKGROUND: Postoperative adhesions are a major cause of morbidity, accounting for approximately 5% of the readmissions of surgical patients. Bowel obstruction is attributed to adhesions in more than half of the cases, many of which are following colon and rectal surgery. Laparoscopic surgery has the potential advantage of reduced adhesion formation owing to attenuated surgical trauma, less tissue handling, and smaller scars. However, the translation of these advantages to a reduced rate of bowel obstruction has not been sufficiently demonstrated. The aim of this study was to assess the rate of adhesion-related bowel obstruction after laparoscopic colon and rectal surgery. METHODS: Data regarding all cases of laparoscopic colon and rectal surgery were prospectively collected. Information relative to demographics, surgical procedures, and follow-up was analyzed, and patients who were readmitted for bowel obstruction were identified. RESULTS: Over a period of 8 years, 306 patients, at a mean age of 63 years, had a laparoscopic colon and rectal operation in our department-122 for benign conditions and 184 for malignant disease. The mean length of follow-up was 38 months. Six cases (2%) of bowel obstruction, which were unrelated to hernia or advanced cancer, were identified. Two patients had a history of open surgery, in addition to the laparoscopic procedure, so adhesions could be attributed solely to the laparoscopic procedure in 4 patients, which consisted of 1.3% of the total study group. Obstruction occurred within 2 weeks of surgery in 2 patients, and one early reoperation was required. CONCLUSIONS: The incidence of adhesion ileus after laparoscopic colon and rectal surgery appears to be very low. This long-term benefit of laparoscopic surgery should be considered when comparing this technique to its open counterpart.     

Integrated Jingmenvirus Polymerase Gene in Ixodes ricinus Genome

Members of the jingmenviruses group have been found in arthropods and mammals on all continents except Australia and Antarctica. Two viruses of this group were isolated from patients with fever after a tick bite. Using a nested RT-PCR assay targeting a jingmenvirus polymerase gene fragment, we screened ticks collected in seven regions of Russia and found that the abundant jingmenvirus-positive were of Ixodes ricinus species, with the prevalence ranging from 19.8% to 34.3%. In all cases, DNase/RNase treatment suggested that the detected molecule was DNA and subsequent next generation sequencing (NGS) proved that the viral polymerase gene was integrated in the I. ricinus genome. The copy number of the integrated polymerase gene was quantified by qPCR relative to the ITS2 gene and estimated as 1.32 copies per cell. At least three different genetic variants of the integrated polymerase gene were found in the territory of Russia. Phylogenetic analysis of the integrated jingmenvirus polymerase gene showed the highest similarity with the sequence of the correspondent gene obtained in Serbia from I. ricinus.     

Sodium–glucose cotransporter-2 inhibitors in heart failure: Potential decongestive mechanisms and current clinical studies

Congestion is a key pathophysiological feature of heart failure (HF) syndrome that drives most of the clinical manifestations of acute HF and is related with poor quality of life and outcomes. Therefore, safe and effective decongestion is an important therapeutic target in the management of acute HF and despite the use of guideline-recommended loop diuretics, adequate decongestion is not always achieved in patients with acute HF. Recently, sodium–glucose cotransporter-2 (SGLT-2) inhibitors have been shown to provide clinical benefits across a broad spectrum of patients with HF, including consistent reduction in the risk of acute HF episodes. While the exact mechanisms underlying these benefits remain a matter of debate, a growing body of evidence suggests that effective decongestion may be partly responsible, especially in the setting of acute HF. In this review, we discuss the potential decongestive mechanisms of SGLT-2 inhibitors, such as osmotic diuresis, natriuresis, preservation of glomerular filtration and facilitation of interstitial drainage, which can collectively translate into effective and safe decongestion. Furthermore, we provide a comprehensive review of up-to-date clinical data of SGLT-2 inhibitor use in the acute HF population.     

The blunted loop diuretic response in acute heart failure is driven by reduced tubular responsiveness rather than insufficient tubular delivery. The role of furosemide urine excretion on diuretic and natriuretic response in acute heart failure

Aims

Diuretic response in heart failure is blunted when compared to healthy individuals, but the pathophysiology underlying this phenomenon is unclear. We aimed to investigate whether the diuretic resistance mechanism is related to insufficient furosemide tubular delivery or low tubular responsiveness.

Methods and results

We conducted a prospective, observational study of 50 patients with acute heart failure patients divided into two groups based on previous furosemide use (furosemide naïve: n = 28 [56%] and chronic furosemide users: n = 22 [44%]). Each patient received a protocol-derived, standardized furosemide dose based on body weight. We measured diuretic response and urine furosemide concentrations. The furosemide naïve group had significantly higher urine volumes and natriuresis when compared to chronic users at all timepoints (all p < 0.05). Urine furosemide delivery was similar in furosemide naïve versus chronic users after accounting for differences in estimated glomerular filtration rate (28.02 [21.03–35.89] vs. 29.70 [18.19–34.71] mg, p = 0.87). However, the tubular response to delivered diuretic was dramatically higher in naïve versus chronic users, that is the urine volume per 1 μg/ml of urine furosemide at 2 h was 148.6 ± 136.1 versus 50.6 ± 56.1 ml (p = 0.005).

Conclusions

Patients naïve to furosemide have significantly better diuresis and natriuresis when compared to chronic furosemide users. The blunted diuretic response in patients with chronic loop diuretic exposure is driven by decreased tubular responsiveness rather than insufficient furosemide tubular delivery.     

Safety and performance of a novel implantable sensor in the inferior vena cava under acute and chronic intravascular volume modulation

Aims

The management of congestion is one of the key treatment targets in heart failure. Assessing congestion is, however, difficult. The purpose of this study was to investigate the safety and dynamic response of a novel, passive, inferior vena cava (IVC) sensor in a chronic ovine model.

Methods and results

A total of 20 sheep divided into three groups were studied in acute and chronic in vivo settings. Group I and Group II included 14 sheep in total with 12 sheep receiving the sensor and two sheep receiving a control device (IVC filter). Group III included an additional six animals for studying responses to volume challenges via infusion of blood and saline solutions. Deployment was 100% successful with all devices implanted; performing as expected with no device-related complications and signals were received at all observations. At similar volume states no significant differences in IVC area normalized to absolute area range were measured (55 ± 17% on day 0 and 62 ± 12% on day 120, p = 0.51). Chronically, the sensors were completely integrated with a thin, reendothelialized neointima with no loss of sensitivity to infused volume. Normalized IVC area changed significantly from 25 ± 17% to 43 ± 11% (p = 0.007) with 300 ml infused. In contrast, right atrial pressure required 1200 ml of infused volume prior to a statistically significant change from 3.1 ± 2.6 mmHg to 7.5 ± 2.0 mmHg (p = 0.02).

Conclusion

In conclusion, IVC area can be measured remotely in real-time using a safe, accurate, wireless, and chronic implantable sensor promising to detect congestion with higher sensitivity than filling pressures.