Optimal side of implant for single-lead VDD pacing: right-sided versus left-sided implantation

BACKGROUND: Atrial undersensing occurs in a considerable number of patients with single-lead VDD pacing. This study tried to determine the role of implant side in maintenance of the VDD mode in patients with isolated atrioventricular (AV) block. METHODS: Eighty-two patients with isolated AV block (46 females; mean age, 58 +/- 17 years) received a single-lead VDD pacemaker (Medtronic Kappa, n = 70 and St. Jude Medical Affinity, n = 12). The patients were randomly assigned to one of two implantation groups (group I: right-sided VDD and group II: left-sided VDD). In each group, the P-wave amplitudes were determined at implantation, predischarge, 2-month, and 6-month follow-up. At each follow-up visit, stored event histograms of pacemaker were also retrieved. The atrial sensing measurements were compared between two groups. RESULTS: Implantation was easier from right side (1.7 +/- 1.0 vs 2.8 +/- 1.7 attempts, P = 0.001). Implant P-wave was higher in group I compared to group II (4.2 +/- 1.7 vs 2.7 +/- 1.0 mV, P < 0.0001). During follow-up, higher P-wave amplitudes were obtained in group I both at predischarge (2.6 +/- 1.3 vs 1.4 +/- 1.1 mV, P < 0.0001), 2-month (2.8 +/- 1.8 vs 1.3 +/- 1.0 mV, P < 0.0001), and 6-month (2.9 +/- 1.7 vs 1.3 +/- 0.9 mV, P < 0.0001) evaluations but remained stable throughout the 6 months in both groups. After implantation, VDD function was better maintained in group I than group II (100% vs 90%, P = 0.026). Incidence of atrial undersensing was lower in group I than group II (P = 0.026) in last follow-up visit. CONCLUSIONS: Implant side has a significant influence on atrial sensing performance in single-lead VDD pacing. Thus, right-side implantation should be the preferred approach for the implantation of VDD single-lead systems.     

IL-2 mediates NK cell proliferation but not hyperactivity

Natural killer cells play a major role in innate immunity against tumor and virus-infected cells. NK cells express activating and inhibitory receptors to regulate their function. It has been established that modulation in the NK cell receptor profile results in altered function of NK cell against target cells. Here, we study the effect of IL-2 stimulation on NK cell inhibitory receptors Ly49A, Ly49C, and activating receptor Ly49D in C57BL/6 mice. It was observed that there was significant increase in expression of Ly49A but no change in expression of Ly49C and Ly49D on IL-2 stimulation. We further noticed that although IL-2 stimulation increased the NK cell population and expression of activation marker NK1.1 but IL-2 stimulation does not cause hyper-responsiveness in NK cells, as there was no increase in MIP-1α and IFN-γ production in IL-2 stimulated NK cells as compared to unstimulated controls. These findings provide a framework to understand the effect of IL-2 stimulation on cognate and non-cognate receptor ligand interactions and suggest stratagies for immunotherapies in conjunction with IL-2 combinatorial therapies.     

Associations between Potential Bacterial Pathogens in the Nasopharynx of HIV Infected Children

Objective

To investigate bacterial associations of S. pneumoniae, S. aureus, and H. influenzae in the nasopharynx of ambulatory children with HIV infection.

Methods

A cross-sectional nasopharyngeal swab survey of 148 children with HIV infection from West Bengal presenting for routine outpatient care was conducted.

Results

Forty-one (28 %) children carried S. pneumoniae, 35 (24 %) carried S. aureus and 39 (26 %) carried H. influenzae. Seventeen (11 %) had dual colonization with S. pneumoniae and H. influenzae, 13(8.8 %) had dual colonization with S. pneumoniae and S. aureus, and 6(4 %) had dual colonization with S. aureus and H. influenzae. Three (2 %) had triple carriage with H. influenzae, S. aureus, and S. pneumoniae. Neither Cotrimoxazole prophylaxis nor ART (antiretroviral therapy) affected colonization with any organism. There was no association between HIV immune status, recent antibiotic use, exposure to other children, household tuberculosis exposure and colonization with any organism. There was a strong negative association between malnutrition and colonization with H. influenzae.

Conclusions

The negative association between S. pneumoniae and S. aureus colonization in the nasopharynx described in healthy populations was not present. The authors found a strong positive association between carriage with H. influenzae and S. pneumoniae. These findings provide insight into the increased risk of invasive disease from these organisms in HIV infected children.     

Association of COVID-19 with hepatic metabolic dysfunction

The coronavirus disease 2019 (COVID-19) pandemic continues to be a global problem with over 438 million cases reported so far. Although it mostly affects the respiratory system, the involvement of extrapulmonary organs, including the liver, is not uncommon. Since the beginning of the pandemic, metabolic com-orbidities, such as obesity, diabetes, hypertension, and dyslipidemia, have been identified as poor prognostic indicators. Subsequent metabolic and lipidomic studies have identified several metabolic dysfunctions in patients with COVID-19. The metabolic alterations appear to be linked to the course of the disease and inflammatory reaction in the body. The liver is an important organ with high metabolic activity, and a significant proportion of COVID-19 patients have metabolic comorbidities; thus, this factor could play a key role in orchestrating systemic metabolic changes during infection. Evidence suggests that metabolic dysregulation in COVID-19 has both short- and long-term metabolic implications. Furthermore, COVID-19 has adverse associations with metabolic-associated fatty liver disease. Due to the ensuing effects on the renin-angiotensin-aldosterone system and ammonia metabolism, COVID-19 can have significant implications in patients with advanced chronic liver disease. A thorough understanding of COVID-19-associated metabolic dysfunction could lead to the identification of important plasma biomarkers and novel treatment targets. In this review, we discuss the current understanding of metabolic dysfunction in COVID-19, focusing on the liver and exploring the underlying mechanistic pathogenesis and clinical implications.     

Comparison of an automated enzyme immunoassay with a direct fluorescent antibody test and polymerase chain reaction for the detection ofChlamydia trachomatis in diagnostic specimens from male patients

Endourethral swabs and first-pass urine (FPU) samples from 148 male patients were tested forChlamydia trachomatis by an automated enzyme immunoassay (EIA) (Vidas; bioMérieux, France), a direct fluorescent antibody (DFA) test (MicroTrak; Syva, USA) and two polymerase chain reaction (PCR) methods.Chlamydia trachomatis was considered present if a specimen was positive by at least two methods. This expanded criterion identified 27 patients (18%) as truly infected. One of the PCR methods was most sensitive for both types of specimen. When the recommended cut-off value of Vidas was reduced by 50%, its sensitivity on endourethral swabs was comparable to that of the DFA test, but the DFA test performed better with FPU. In general, FPU was suitable only for PCR.     

Osteological study of lumbar vertebrae in Western Maharashtra population

Introduction: Anatomical studies have been conducted in different ethnic groups to measure the bony vertebral dimensions and to determine the normal limits which will serve as guidelines in assessing lumbar stenosis. Aim: To determine the normal range of measurements of lumbar vertebrae in Western Maharashtra population. Materials and methods: Various dimensions of lumbar vertebrae from L₁ to L₅ were measured in 420 lumbar vertebrae, collected from the Department of Anatomy, Government Medical College, Miraj, and other Medical colleges of Western Maharashtra. Results and discussion: Mean transverse diameter of vertebral body as well as of spinal canal and anteroposterior diameter of vertebral body were minimum at L₁ and maximum at L₅. The mean anteroposterior diameter of spinal canal showed a gradual decrease from L₁ to L₅ in both sexes. Making use of the above parameters, the canal body ratio and spinal index of Jones were calculated. These parameters were also compared with those of previous studies. Similarly, from the above parameters, the values suggestive of lumbar canal stenosis and intraspinal tumor were calculated. Conclusion: The present study shows regional and ethnic variation in the parameters of lumbar vertebrae, thus emphasizing the need to determine the normal range of values for different populations.