A Prospective Study of Serotonin and Norepinephrine Transporter Genes and the Response to Desvenlafaxine Over 8 Weeks in Major Depressive Disorder

No studies to date have evaluated SLC6A2 and SLC6A4 genetic polymorphisms influencing antidepressant response to desvenlafaxine. We conducted an 8-week, open-label, prospective pilot study in 35 patients with major depressive disorder to assess the effects of genetic variations in SLC6A2 and SLC6A4 on both efficacy and side effect profile of desvenlafaxine. Results revealed that homozygotes for the SLC6A4 HTTLPR S allele showed a 33% HDRS reduction compared to a 58% reduction for L allele carriers (p=0.037). No results survived adjustments for covariates or multiple comparisons. While these results need to be interpreted cautiously, they provide preliminary support for the SLC6A4 HTTLPR polymorphism as potential modifier of desvenlafaxine efficacy.

Screening women with menorrhagia for underlying bleeding disorders: the utility of the platelet function analyser and bleeding time

Menorrhagia is a very common clinical problem among women of reproductive age and recent studies have suggested that underlying bleeding disorders, particularly von Willebrand's deficiency and platelet function defects, are prevalent in women presenting with menorrhagia. The objective of this study was to determine the utility of the platelet function analyser (PFA-100) and bleeding time (BT) as initial screening tests for underlying bleeding disorders in women with menorrhagia. In this study, 81 women with a physician diagnosis of menorrhagia underwent PFA-100 testing, BT and comprehensive haemostatic testing. The effectiveness of the PFA-100 and BT as screening tools in women with menorrhagia was assessed using results of haemostatic testing for von Willebrand's disease (VWD) and platelet dysfunction. In women presenting with menorrhagia, the PFA-100 had a sensitivity 80%, specificity 89%, positive predictive value (PPV) 33%, negative predictive value (NPV) 98% and efficiency 88% for VWD. For platelet aggregation defects, the PFA-100 closure time had a sensitivity 23%, specificity 92%, PPV of 75%, NPV of 52% and efficiency 55%. The data suggest that the PFA-100 may be useful in stratifying women with menorrhagia for further von Willebrand testing; however, neither the PFA-100 nor the BT tests are effective for purposes of classifying women for standard platelet aggregometry testing in women presenting with menorrhagia.

Comparison of Sentinel and Bactec blood culture systems

AIMS

To evaluate the Sentinel automated blood culture system and to compare its performance with that of Bactec.

METHODS

The Sentinel blood culture system was evaluated in three centres. The performance of the system was assessed in comparison with the routine blood culture method used in these centres, the Bactec system.

RESULTS

Blood culture sets (n = 2180) consisting of Sentinel aerobic and anaerobic, and Bactec aerobic and anaerobic bottles yielded 218 (10%) clinically important isolates. One hundred and fifty five (71%) of the isolates were detected by both systems; 35 (16%) were detected by Sentinel only; and 28 (13%) by Bactec only. For the duration of the evaluation, the Sentinel system was deliberately configured so that it was impossible to detect positive results during the first 12 hours. The times to positivity after the first 12 hours were similar. Data gathered during and subsequent to the evaluation have been used by the manufacturer to refine the algorithm so that positive results can be detected at a minimum of 2.25 hours.

CONCLUSIONS

After a period of familiarization the Sentinel system was considered easy to use. Sentinel is a useful addition to the methods available for the detection of bacteria in blood cultures.

Simultaneous identification of viral proteins and nucleic acids in cells infected with Aleutian mink disease parvovirus

A method combining in situ hybridization and immunohistochemistry was used to characterize cells infected with Aleutian mink disease parvovirus (ADV). Single-stranded RNA hybridization probes specific for obligate replicative intermediates and antisera specific for virion or non-structural proteins were employed. Crandell feline kidney cells in which the ADV-G strain of ADV was permissively replicating contained virion and non-structural proteins, large amounts of single stranded virion DNA, duplex replicative form (RF) DNA, and mRNA. Late in the infectious cycle, however, cells containing non-structural proteins but little nucleic acid were observed, probably representing cells in the end stage of viral cytopathology. Sections of lung prepared from mink kits infected with the ADV-Utah 1 strain were then examined. Alveolar type II cells permissively replicating ADV contained viral nucleic acids and proteins in patterns nearly identical to CRFK cells, suggesting that permissive ADV replication was similar in vitro and in vivo. Another population of ADV containing cells that had cytoplasmic virion antigen, but undetectable levels of non-structural protein was found in vivo. Furthermore, although virion DNA was present in the cytoplasm of these cells, RF DNA or mRNA could not be detected. These cells may have been alveolar macrophages sequestering viral particles.

Thermal mapping of the airways in humans

To characterize the intrathoracic thermal events that occur during breathing in humans, we developed a flexible probe (OD 1.4 mm) containing multiple thermistors evenly spaced over 30.2 cm, that could be inserted into the tracheobronchial tree with a fiberoptic bronchoscope. With this device we simultaneously recorded the airstream temperature at six points from the trachea to beyond the subsegmental bronchi in six normal subjects while they breathed ambient and frigid air at multiple levels of ventilation (VE). During quiet breathing of room air the average temperature ranged from 32.0 +/- 0.05 degrees C in the upper trachea to 35.5 +/- 0.3 degrees C in the subsegmental bronchi. As ventilation was increased, the temperature along the airways progressively decreased, and at a VE of 100+ 1/min the temperature at the above two sites fell to 29.2 +/- 0.5 and 33.9 +/- 0.8 degrees C, respectively. Interval points were intermediate between these extremes. With cold air, the changes were considerably more profound. During quiet breathing, local temperatures approximated those recorded in the maximum VE room-air trial, and at maximum VE, the temperatures in the proximal and distal airways were 20.5 +/- 0.6 and 31.6 +/- 1.2 degrees C, respectively. During expiration, the temperature along the airways progressively decreased as the air flowed from the periphery of the lung to the mouth: the more the cooling during inspiration, the lower the temperature during expiration. These data demonstrate that in the course of conditioning inspired air the intrathoracic and intrapulmonic airways undergo profound thermal changes that extend well into the periphery of the lung.

Thermal mapping of the airways in humans

To characterize the intrathoracic thermal events that occur during breathing in humans, we developed a flexible probe (OD 1.4 mm) containing multiple thermistors evenly spaced over 30.2 cm, that could be inserted into the tracheobronchial tree with a fiberoptic bronchoscope. With this device we simultaneously recorded the airstream temperature at six points from the trachea to beyond the subsegmental bronchi in six normal subjects while they breathed ambient and frigid air at multiple levels of ventilation (VE). During quiet breathing of room air the average temperature ranged from 32.0 +/- 0.05 degrees C in the upper trachea to 35.5 +/- 0.3 degrees C in the subsegmental bronchi. As ventilation was increased, the temperature along the airways progressively decreased, and at a VE of 100+ 1/min the temperature at the above two sites fell to 29.2 +/- 0.5 and 33.9 +/- 0.8 degrees C, respectively. Interval points were intermediate between these extremes. With cold air, the changes were considerably more profound. During quiet breathing, local temperatures approximated those recorded in the maximum VE room-air trial, and at maximum VE, the temperatures in the proximal and distal airways were 20.5 +/- 0.6 and 31.6 +/- 1.2 degrees C, respectively. During expiration, the temperature along the airways progressively decreased as the air flowed from the periphery of the lung to the mouth: the more the cooling during inspiration, the lower the temperature during expiration. These data demonstrate that in the course of conditioning inspired air the intrathoracic and intrapulmonic airways undergo profound thermal changes that extend well into the periphery of the lung.

Influence of cromolyn sodium on airway temperature in normal subjects

It is well established that cromolyn sodium attenuates the bronchoconstriction induced by airway cooling in both normal and asthmatic subjects. To determine whether this protection derives from a modification of the thermal events that transpire during the conditioning of inspired air, we first recorded the effect of cromolyn on the bronchoconstrictor response to hyperventilation with frigid air in 7 normal subjects. On a separate occasion, we imposed the same thermal burden and measured the temperature at multiple sites within the airways before and after pretreatment with cromolyn. The first cold air challenge produced a significant decrease in forced expiratory volume in one second (FEV1) of 5.5 +/- 0.9% (SEM) and these changes were significantly reduced by cromolyn (FEV1 = 2.8 +/- 0.9%; p less than 0.05). In concert with the improvement in mechanics, the temperatures (T) within the trachea (tr) and the anterior segment of the right lower lobe (AS-RLL) were significantly higher after cromolyn (Ttr = 1.3 +/- 0.2 degrees C; p less than 0.01; TAS-RLL = 1.0 +/- 0.4 degrees C; p = 0.05), and there was a direct positive relationship between the mechanical protection offered by the drug and the increase in airway temperature (Spearman's rank correlation coefficient = 0.83; p = 0.05). These data suggest that cromolyn modifies respiratory heat exchange in such a fashion as to limit airway cooling. The mechanism of this action is not presently known but may reflect a direct or indirect influence on the bronchial vasculature.