Polymorphisms of adrenergic cardiovascular control genes are associated with adolescent chronic fatigue syndrome

Aim: To explore the frequency of polymorphisms in adrenergic cardiovascular control genes in adolescent with chronic fatigue syndrome (CFS) and the relation of such polymorphisms to cardiovascular variables. Methods: DNA from 53 patients with CFS, 12–18 years old, was analysed for five single nucleotide polymorphisms (SNPs) in the genes catechol‐O‐methyltransferase (COMT), the β₂‐adrenergic receptor (two SNPs), the β₁‐adrenergic receptor and the α_2a‐adrenergic receptor. Frequencies were compared to a reference population constructed from the National Center for Biotechnology Information (NCBI) database, and associations between frequencies and autonomic cardiovascular responses during a 20° head‐uptilt‐test were explored. Results: For the COMT SNP Rs4680, patients with CFS had a higher frequency of the AA genotype and a lower frequency of the G containing genotypes (AG and GG), when compared to the reference sample (p = 0.046). Also, the AA genotype was associated with a smaller increase in LF/HF ratio (low‐frequency:high‐frequency heart rate variability ratio, an index of cardiac sympathovagal balance) during head‐up tilt when compared to the AG/GG genotypes. For the β₂‐adrenergic receptor SNP Rs1042714, patients with CFS had a lower frequency of the GG genotype and a higher frequency of the genotypes containing C (CG and CC) (p = 0.044). Conclusions: CFS might be related to polymorphisms of COMT and the β₂‐adrenergic receptor. More details of the molecular mechanisms remain to be investigated.     

Treatment of chronic fatigue and orthostatic intolerance with propranolol

We describe the effect of propranolol in an adolescent with chronic fatigue syndrome and orthostatic intolerance. Our observations suggest that the head-up tilt-test and beta-blocker treatment might be considered in patients with chronic fatigue syndrome and that enhanced sympathetic nervous activity might be part of the underlying pathophysiology.     

Standardization of extracellular vesicle measurements by flow cytometry through vesicle diameter approximation

Essentials

• Platelet extracellular vesicles (EVs) concentrations measured by flow cytometers are incomparable.
• A model is applied to convert ambiguous scatter units to EV diameter in nanometer.
• Most included flow cytometers lack the sensitivity to detect EVs of 600 nm and smaller.
• The model outperforms polystyrene beads for comparability of platelet EV concentrations.

Summary

Background

Detection of extracellular vesicles (EVs) by flow cytometry has poor interlaboratory comparability, owing to differences in flow cytometer (FCM) sensitivity. Previous workshops distributed polystyrene beads to set a scatter‐based diameter gate in order to improve the comparability of EV concentration measurements. However, polystyrene beads provide limited insights into the diameter of detected EVs.

Objectives

To evaluate gates based on the estimated diameter of EVs instead of beads.

Methods

A calibration bead mixture and platelet EV samples were distributed to 33 participants. Beads and a light scattering model were used to set EV diameter gates in order to measure the concentration of CD61–phycoerythrin‐positive platelet EVs.

Results

Of the 46 evaluated FCMs, 21 FCMs detected the 600–1200‐nm EV diameter gate. The 1200–3000‐nm EV diameter gate was detected by 31 FCMs, with a measured EV concentration interlaboratory variability of 81% as compared with 139% with the bead diameter gate. Part of the variation in both approaches is caused by precipitation in some of the provided platelet EV samples. Flow rate calibration proved essential because systems configured to 60 μL min^?1 differed six‐fold in measured flow rates between instruments. Conclusions EV diameter gates improve the interlaboratory variability as compared with previous approaches. Of the evaluated FCMs, 24% could not detect 400‐nm polystyrene beads, and such instruments have limited utility for EV research. Finally, considerable differences were observed in sensitivity between optically similar instruments, indicating that maintenance and training affect the sensitivity.

     

Multimeric composition of endothelial cell-derived von Willebrand factor

The multimeric composition of human endothelial cell (EC)-derived von Willebrand factor (vWF) was studied using SDS-agarose gel electrophoresis and autoradiography. Two multimers were found in lysates prepared from confluent cultures of human umbilical vein endothelial cells. The smaller multimer had a molecular weight (mol wt) of approximately 950 Kd, while the second was larger than those seen in plasma. When electrophoresis was performed using the discontinuous buffer system of Ruggeri and Zimmerman, the small multimer consisted of a single band migrating with the slowest-moving component of the corresponding plasma triplet. The large EC-vWF multimer was detected in culture media conditioned with EC monolayers for ten minutes. It remained the only multimer in media conditioned for up to three days. Calcium ionophore A23187 increased the amount of the large vWF multimer released into the culture media, but did not change its multimeric composition. The small multimer was never detected in the EC- conditioned media. These findings suggest that (1) a large, fully polymerized multimer of vWF is released from the ECs, while the small multimer probably represents a major intermediate component in the process of multimerization, and (2) plasma vWF multimers are probably generated from the large endothelial vWF after it is released into the circulation.     

Evaluation of Aerosol and Water Contamination and Control of Cross Infection in Dental Clinics

Background

The oral cavity is an unique environment which provides an ideal medium for bacterial growth. As a result of repeated exposure to the microorganisms present in blood and saliva, the dental health professionals and the patients are at a higher risk for developing many infectious diseases. A pilot study was carried out in the Dept of Dental Surgery, Armed Forces Medical College to assess the risk of cross infection in dental clinics.

Methods

Samples were collected from different dental surgeries of the Dept of Dental Surgery, Armed Forces Medical College and sent for microbiological culture and identification to the Dept of Microbiology, Armed Forces Medical College. The sampling was carried out in two stages, before and after implementing a set protocol.

Result

All dental unit waterlines were coated with a well established biofilm made up of filamentous and bacillus-like microorganisms in first stage of study. There was marked reduction in the number of colonies from the samples collected during second stage. Same findings were observed in the samples of aerosol produced by ultrasonic scalers.

Conclusion

The present study concluded that the new set protocol followed is significantly effective in reducing the microbial load in the water tubing, container and aerosol production. It is an effective measure for reducing the chances of cross infection in the dental surgeryKey Words: Aerosol, Biofilm, Cross infection, Colony forming units     

The relative stress scale,a useful instrument to identify various aspects of carer burden in dementia?

OBJECTIVE: To identify carer and patient characteristics associated with various aspects of burden of care. METHOD: The burden on 196 carers, each caring for one patient with dementia, was rated by means of the Relative Stress Scale (RSS). Patients were assessed with the Mini Mental State Examination (MMSE), the Disability Assessment for Dementia (DAD) and the Neuropsychiatric Inventory (NPI). RESULTS: Factor analysis of the RSS resulted in three subgroups: 'emotional distress', 'social distress' and 'negative feelings'. The total NPI score contributed to the explanation of the RSS total score and the three RSS subgroup scores with an explanatory power of 37% for total RSS, 34% for emotional distress, 27% for social distress and 20% for negative feelings. In multiple regression analysis, total NPI, DAD%, the carer being a wife and the hours spent caring per week, contributed to the explanation of total RSS with an explanatory power of 48%. Total NPI, the carer being a female and the hours spent caring, explained 38% of the variance in 'emotional distress'. Total NPI, the DAD%-score, contact with the patient on a daily basis and the hours spent caring, explained 'social distress' (49%). 'Negative feelings' were associated with total NPI, younger patients and the carer being a wife (27%). CONCLUSIONS: The RSS offers an opportunity to differentiate between different patterns of distress. This facilitates the creation of tailored intervention to reduce the strain of caring.     

High score on the Relative Stress Scale, a marker of possible psychiatric disorder in family carers of patients with dementia

OBJECTIVE: To compare the scores on the Relative Stress Scale (RSS) with those on the General Health Questionnaire (GHQ) and the Geriatric Depression Scale (GDS), and to establish a cut-off score for RSS in order to distinguish carers with symptoms of psychiatric disorders from those without. METHODS: One hundred and ninety-four carers of 194 patients suffering from dementia according to ICD-10 were included in the study. Burden of care was assessed by the 15-items RSS, and psychiatric symptoms by means of the GHQ-30 and the 30-items GDS. A case score above 5 on GHQ and above 13 on GDS were used to define carers with probable psychiatric morbidity. Sensitivity (SS), specificity (SP), accuracy and likelihood ratio for a positive test (LR+) were calculated for different cut-points of the RSS. RESULTS: Fifty-six percent of the carers had a GHQ score above 5, and 22% had a GDS score above 13. A two-step cluster analysis using 192 of the 194 carers, identified three groups of carers; a low risk group for psychiatric morbidity (LRG), 82 carers with GHQ < or = 5 and GDS < or = 13; a medium risk group (MRG), 69 carers with GHQ > 5 and GDS < or = 13; and a high-risk group (HRG), 40 carers with GHQ > 5 and GDS > 13. The optimal RSS cut-off to distinguish between the LRG and the others was > 23 (SS 0.72, SP 0.82, accuracy 0.76, LR + 4.0), whereas the optimal cut-off to separate the HRG from the others was >30 (SS 0.74, SP 0.87, accuracy 0.84, LR + 5.7). CONCLUSION: The RSS is a useful instrument to stratify carers according to their risk of psychiatric morbidity.