A review on host-pathogen interactions: classification and prediction.

The research on host-pathogen interactions is an ever-emerging and evolving field. Every other day a new pathogen gets discovered, along with comes the challenge of its prevention and cure. As the intelligent human always vies for prevention, which is better than cure, understanding the mechanisms of host-pathogen interactions gets prior importance. There are many mechanisms involved from the pathogen as well as the host sides while an interaction happens. It is a vis-a-vis fight of the counter genes and proteins from both sides. Who wins depends on whether a host gets an infection or not. Moreover, a higher level of complexity arises when the pathogens evolve and become resistant to a host's defense mechanisms. Such pathogens pose serious challenges for treatment. The entire human population is in danger of such long-lasting persistent infections. Some of these infections even increase the rate of mortality. Hence there is an immediate emergency to understand how the pathogens interact with their host for successful invasion. It may lead to discovery of appropriate preventive measures, and the development of rational therapeutic measures and medication against such infections and diseases. This review, a state-of-the-art updated scenario of host-pathogen interaction research, has been done by keeping in mind this urgency. It covers the biological and computational aspects of host-pathogen interactions, classification of the methods by which the pathogens interact with their hosts, different machine learning techniques for prediction of host-pathogen interactions, and future scopes of this research field.

Shoe and Field Surface Risk Factors for Acute Lower Extremity Injuries Among Female Youth Soccer Players.

OBJECTIVE: To describe acute lower extremity injuries and evaluate extrinsic risk factors in female youth soccer. DESIGN: Nested case-control study. SETTING: Youth soccer clubs in Seattle, WA. PARTICIPANTS: Female soccer players (n = 351) ages 11 to 15 years randomly selected from 4 soccer clubs from which 83% of their players were enrolled with complete follow-up for 92% of players. INTERVENTIONS: Injured players were interviewed regarding injury, field surface, shoe type, and position. Uninjured controls, matched on game or practice session, were also interviewed. MAIN OUTCOME MEASURES: The association between risk factors and acute lower extremity injury using logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI). RESULTS: One hundred seventy-three acute lower extremity injuries occurred involving primarily the ankle (39.3%), knee (24.9%), and thigh (11.0%). Over half (52.9%) recovered within 1 week, whereas 30.2% lasted beyond 2 weeks. During practices, those injured were approximately 3-fold (OR, 2.83; 95% CI, 1.49-5.31) more likely to play on grass than artificial turf and 2.4-fold (95% CI, 1.03-5.96) more likely to wear cleats on grass than other shoe and surface combinations. During games, injured players were 89% (95% CI, 1.03-4.17) more likely to play defender compared with forward. CONCLUSIONS: Half of the acute lower extremity injuries affected the ankle or knee. Grass surface and wearing cleats on grass increased training injuries. CLINICAL RELEVANCE: The majority, 64%, of female youth soccer players' acute injuries involve the ankle and knee and injury prevention strategies in this age group should target these areas. When considering playing surfaces for training, communities and soccer organizations should consider the third-generation artificial turf a safe alternative to grass.

A randomized, double-blind phase I/IIa study of intranasal glutathione in Parkinson's disease.

BACKGROUND: Depletion of reduced glutathione is associated with PD and glutathione augmentation has been proposed as a disease-modifying strategy. The aim of this study was to determine the safety and tolerability of intranasal reduced glutathione in individuals with PD. METHODS: Thirty individuals with PD were randomized to either placebo (saline), 300 mg/day, or 600 mg/day of intranasal glutathione in three divided daily doses. Follow-up visits included side effect screening of PD symptoms and cognition, blood chemistry, sinus irritation, and hyposmia. Tolerability was measured by frequency and severity of reported adverse events, compliance, and withdrawals from the study. RESULTS: After 3 months, there were no substantial differences between groups in the number of adverse events reported or observed among all safety measures assessed. All groups met tolerability criteria. CONCLUSIONS: These data support the safety and tolerability of intranasal glutathione in this population. Pharmacokinetic and dose-finding studies are warranted.

Agreement between allergen-specific IgE assays and ensuing immunotherapy recommendations from four commercial laboratories in the USA.

BACKGROUND: Canine allergen-specific IgE assays in the USA are not subjected to an independent laboratory reliability monitoring programme. HYPOTHESIS/OBJECTIVES: The aim of this study was to evaluate the agreement of diagnostic results and treatment recommendations of four serum IgE assays commercially available in the USA. METHODS: Replicate serum samples from 10 atopic dogs were submitted to each of four laboratories for allergen-specific IgE assays (ACTT(®) , VARL Liquid Gold, ALLERCEPT(®) and Greer(®) Aller-g-complete(®) ). The interlaboratory agreement of standard, regional panels and ensuing treatment recommendations were analysed with the kappa statistic (κ) to account for agreement that might occur merely by chance. Six comparisons of pairs of laboratories and overall agreement among laboratories were analysed for ungrouped allergens (as tested) and also with allergens grouped according to reported cross-reactivity and taxonomy. RESULTS: The overall chance-corrected agreement of the positive/negative test results for ungrouped and grouped allergens was slight (κ = 0.14 and 0.13, respectively). Subset analysis of the laboratory pair with the highest level of diagnostic agreement (κ = 0.36) found slight agreement (κ = 0.13) for ungrouped plants and fungi, but substantial agreement (κ = 0.71) for ungrouped mites. The overall agreement of the treatment recommendations was slight (κ = 0.11). Altogether, 85.1% of ungrouped allergen treatment recommendations were unique to one laboratory or another. CONCLUSIONS AND CLINICAL IMPORTANCE: Our study indicated that the choice of IgE assay may have a major influence on the positive/negative results and ensuing treatment recommendations.

Reproducibility of a quantitative cutaneous cytological technique.

BACKGROUND: Cutaneous cytology is a valuable tool for diagnosis of canine superficial pyoderma. Current published reproducible techniques are semiquantitative. HYPOTHESIS/OBJECTIVES: The aim of this study was to evaluate the reproducibility of a quantitative method for skin surface cytology in dogs with superficial pyoderma. ANIMALS: Impression smears were collected from five normal dogs and 20 dogs with clinical and cytological evidence of superficial pyoderma. METHODS: Four investigators evaluated 10 oil immersion fields (OIF) on 25 slides, selecting fields with inflammatory cells, nuclear streaming and or keratinocytes under ×10 magnification. Investigators repeated blinded evaluations of all slides at least twice. For each OIF, polymorphonuclear leukocytes (PMNs), intracellular (IC) cocci, extracellular (EC) cocci, IC rods, EC rods and yeast were quantified. Nuclear streaming was scored as present or absent. For each parameter, within-reader and between-reader agreements were expressed by the intraclass correlation (ICC) value (≤0.20 poor, 0.21-0.40 fair, 0.41-0.60 moderate, 0.61-0.80 good and 0.81-1.00 excellent) or kappa statistic (κ). RESULTS: Reproducible parameters included: PMNs (ICC = 0.58), nuclear streaming (ICC = 0.68), EC cocci (ICC = 0.64) and IC cocci (ICC = 0.32). When qualified as present or absent, within-reader κ for IC cocci was 0.71. The method demonstrated 93% sensitivity in identifying dogs with superficial pyoderma and 51% specificity in identifying normal dogs according to established criteria. However, if criteria for normal dogs were limited to the absence of PMNs and IC bacteria, sensitivity of 64% and specificity of 98% were demonstrated. CONCLUSIONS AND CLINICAL IMPORTANCE: For several parameters, including PMNs, nuclear streaming, EC cocci and IC cocci, a reproducible, quantitative cytological technique was identified.

Evaluation of the Zachery Lystedt Law among female youth soccer players.

BACKGROUND: Despite recent increased awareness about sports concussions, few studies have evaluated the effect of concussion laws on concussion outcomes among young athletes. The purpose of our study was to evaluate the effect of the Washington State Zachery Lystedt Concussion Law on playing with concussion symptoms and being evaluated by a health care provider. METHODS: We performed a prospective cohort study of 351 elite female soccer players, aged 12 to 15 years, from 33 randomly selected youth soccer teams in the Puget Sound region of Washington State from 2008 to 2012. The Washington State Zachery Lystedt Concussion Law went into effect on July 1, 2009. Among concussed players (N = 59), we assessed the risk of playing with symptoms, the evaluation by a health care professional, and receiving a concussion diagnosis before and after the law was passed using logistic regression to estimate odds ratios and 95% CIs. RESULTS: The majority of concussed players (59.3%) continued to play with symptoms, and we found no statistically significant difference in the proportion of players who played with symptoms before and after the law was passed. Only 44.1% of concussed players were evaluated by a health care provider, with no difference before and after the law was passed. Among those evaluated by a health care professional, players were 2.1-fold (95% CI, 1.0-10.1) more likely to receive a concussion diagnosis after the law was passed. CONCLUSION: The majority of concussed female youth soccer players report playing with symptoms. Legislation mandating concussion education and evaluation prior to returning to play was not associated with an increase in concussion evaluations by health care providers.

Temporal distribution of dissolved trace metal in the coastal waters of Southwestern Bay of Bengal, India.

The objective of the present study was to characterize the concentrations of selected dissolved trace metals in the coastal waters (500 m from shore) of Kalpakkam, Tamil Nadu, India. The order of dissolved concentration of these metals was found to be as follows: Co (cobalt) < Cd (cadmium) < Cr (chromium) < Mn (manganese) < Cu (copper) < Ni (nickel) < Pb (lead) < Zn (zinc). The levels of these trace metals were found to be relatively low as compared to the reported values for other Indian coastal waters, which indicates negligible pollution at this location. Cadmium was the only metal found to increase its concentration during the monsoon period, suggesting its allochthonous input. Factor analysis indicated that chromium, nickel, zinc, cobalt, copper, manganese, and lead were of common origin, and external inputs through land runoff had nominal or little impact, typifying in-situ regeneration and remineralization linkage with their temporal variation. However, levels of zinc, cobalt, and copper remained relatively high during the summer period, and abrupt increases in their concentration during December (monsoon season) may be due to their dual (autochthonous as well as allochthonous) input.

A Machine Learning Approach for Predicting Real-time Risk of Intraoperative Hypotension in Traumatic Brain Injury.

BACKGROUND: Traumatic brain injury (TBI) is a major cause of death and disability. Episodes of hypotension are associated with worse TBI outcomes. Our aim was to model the real-time risk of intraoperative hypotension in TBI patients, compare machine learning and traditional modeling techniques, and identify key contributory features from the patient monitor and medical record for the prediction of intraoperative hypotension. METHODS: The data included neurosurgical procedures in 1005 TBI patients at an academic level 1 trauma center. The clinical event was intraoperative hypotension, defined as mean arterial pressure <65 mm Hg for 5 or more consecutive minutes. Two types of models were developed: one based on preoperative patient-level predictors and one based on intraoperative predictors measured per minute. For each of these models, we took 2 approaches to predict the occurrence of a hypotensive event: a logistic regression model and a gradient boosting tree model. RESULTS: The area under the receiver operating characteristic curve for the intraoperative logistic regression model was 0.80 (95% confidence interval [CI]: 0.78-0.83), and for the gradient boosting model was 0.83 (95% CI: 0.81-0.85). The area under the precision-recall curve for the intraoperative logistic regression model was 0.16 (95% CI: 0.12-0.20), and for the gradient boosting model was 0.19 (95% CI: 0.14-0.24). Model performance based on preoperative predictors was poor. Features derived from the recent trend of mean arterial pressure emerged as dominantly predictive in both intraoperative models. CONCLUSIONS: This study developed a model for real-time prediction of intraoperative hypotension in TBI patients, which can use computationally efficient machine learning techniques and a streamlined feature-set derived from patient monitor data.

Development and validation of the Canine Atopic Dermatitis Lesion Index, a scale for the rapid scoring of lesion severity in canine atopic dermatitis.

BACKGROUND: The third iteration of the Canine Atopic Dermatitis Extent and Severity Index (CADESI-03) is the only tool rigorously validated for canine atopic dermatitis (CAD) lesion scoring. The CADESI-03 requires 248 evaluations, limiting its widespread use. HYPOTHESIS/OBJECTIVES: The goal of the study was to develop and validate a practical method of grading CAD lesions that requires scoring only the frequently affected body regions. ANIMALS: Fifty-seven privately owned atopic dogs were used in the study. METHODS: The Canine Atopic Dermatitis Lesion Index (CADLI) was evaluated in an open, multicentre reliability study. Validity was assessed with expert opinion (content validity) and comparison of CADLI with existing disease severity measures (construct and criterion validity). Reliability was evaluated by analysing repeated observations of each dog. Convenience was assessed in terms of the time required to complete the scale. RESULTS: The CADLI scores correlated with overall assessment scores (r = 0.60, P < 0.001, linear mixed model) and pruritus severity scores (r = 0.53, P < 0.001, linear mixed model), establishing construct validity. The CADLI was strongly correlated with CADESI-03 (r = 0.84, P < 0.001, linear mixed model), establishing criterion validity. The CADLI values obtained by two observers correlated very strongly (r = 0.91, P < 0.001), as did the repeat values for the same observer (r = 0.98, P < 0.001). The mean time to complete the CADLI was less than that required for CADESI-03 (1.9 and 12.6 min, respectively), a highly significant difference (P < 0.001). CONCLUSION AND CLINICAL IMPORTANCE: The CADLI was found to be an effective measure of CAD lesion severity, strongly correlating with CADESI-03. The convenience of CADLI makes it suitable for use in both clinical research and practice.

Cytotoxic Effects of Common Irrigation Solutions on Chondrosarcoma and Giant Cell Tumors of Bone.

BACKGROUND: Irrigation is commonly used as an adjuvant treatment during the intralesional curettage of bone tumors. The goal of the present study was to analyze the in vitro cytotoxicity of commonly used irrigation solutions on chondrosarcoma and giant cell tumor (GCT) cells as there is no consensus on which solution leads to the greatest amount of cell death. METHODS: An in vitro evaluation was performed by exposing human GCT and human chondrosarcoma cell lines to 0.9% saline solution, sterile water, 70% ethanol, 3% hydrogen peroxide, 0.05% chlorhexidine gluconate (CHG), and 0.3% povidone iodine solutions independently for 2 and 5 minutes. A low-cytotoxicity control (LCC) and a high-cytotoxicity control (HCC) were established to determine the mean cytotoxicity of each solution and each solution's superiority to LCC and non-inferiority to HCC. RESULTS: The present study demonstrated that 0.05% CHG was non-inferior to the HCC when chondrosarcoma was exposed for 5 minutes and when GCT was exposed for 2 and 5 minutes (mean cytotoxicity, 99% to 102%) (p < 0.003 for all). Sterile water was superior to the LCC when chondrosarcoma was exposed for 5 minutes and when GCT was exposed for 2 minutes (mean, 28% to 37%) (p < 0.05). Sterile water (mean, 18% to 38%) (p < 0.012) and 3% hydrogen peroxide (mean, 7% to 16%) (p < 0.001) were both inferior to the HCC. The 3 other solutions were non-superior to the LCC (mean, -24% to -5%) (p < 0.023). CONCLUSIONS: In vitro irrigation in 0.05% CHG provided high cytotoxicity, comparable with the HCC. Therefore, the use of a 0.05% CHG solution clinically could serve as a potential chemical adjuvant during intralesional curettage of chondrosarcoma and GCT. CLINICAL RELEVANCE: In an effort to reduce the burden of residual tumor cells, irrigation solutions are often utilized as adjuvant local therapy. Use of a 0.05% CHG solution clinically could serve as a potential chemical adjuvant to intralesional curettage of chondrosarcoma and GCT. Further in vivo studies may be indicated to assess clinical outcomes and safety associated with the use of 0.05% CHG in the treatment of chondrosarcoma and GCT.

Comparison of anal sac cytological findings and behaviour in clinically normal dogs and those affected with anal sac disease.

No previous study has explored the relationship between cytology and the frequency of behaviours associated with anal sac disease (ASD). The goals of the study were: (i) to compare the cytological findings between anal sac secretions from normal dogs with no history of ASD to those with non-neoplastic ASD; (ii) to determine whether anal sac cytological findings can be used to differentiate between normal dogs and dogs with ASD; (iii) to explore the correlation of anal sac cytology and behaviour between normal dogs and dogs with ASD; and (iv) to describe behaviours typical of ASD as reported by owners. Thirty dogs were selected for this study, based on their behavioural history as detailed in a questionnaire completed by their owners. Of the thirty dogs, ten were considered normal insofar as they had no history of ASD clinical signs. The remaining 20 dogs were characterized as having ASD, with a chronic history of perianal pruritus, but no other pruritus. All dogs had their anal sacs manually expressed, and the discharge was examined microscopically in a blinded manner. A total of 171 oil immersion fields (OIFs) were examined from normal dogs and 333 OIFs from dogs with ASD. The behavioural results for dogs with ASD revealed that scooting recurred with a median frequency of 3 weeks post-anal sac expression. There were no clinically statistically significant cytological differences between normal dogs and those with ASD, thereby leading to the conclusion that cytology is an ineffective tool for diagnosing ASD.

Implementing Primary Palliative Care in Post-acute nursing home care: Protocol for an embedded pilot pragmatic trial.

INTRODUCTION: Older adults with serious illness frequently receive post-acute rehabilitative care in nursing homes (NH) under the Part A Medicare Skilled Nursing Facility (SNF) Benefit. Treatment is commonly focused on disease-modifying therapies with minimal consideration for goals of care, symptom relief, and other elements of palliative care. INTERVENTION: The evidence-based Primary Palliative Care in Post-Acute Care (PPC-PAC) intervention for older adults is delivered by nurse practitioners (NP). PPC-PAC NPs assess and manage symptoms, conduct goals of care discussions and assist with decision making; they communicate findings with NH staff and providers. Implementation of PPC-PAC includes online and face-to-face training of NPs, ongoing facilitation, and a template embedded in the NH electronic health record to document PPC-PAC. OBJECTIVES: The objectives of this pilot pragmatic clinical trial are to assess the feasibility, acceptability, and preliminary effectiveness of the PPC-PAC intervention and its implementation for 80 seriously ill older adults newly admitted to a NH for post-acute care. METHODS: Design is a two-arm nonequivalent group multi-site pilot pragmatic clinical trial. The unit of assignment is at the NP and unit of analysis is NH patients. Recruitment occurs at NHs in Pennsylvania, New Jersey, Delaware, and Maryland. Effectiveness (patient quality of life) data are collected at two times points-baseline and 14-21 days. CONCLUSION: This will be the first study to evaluate the implementation of an evidence-based primary palliative care intervention specifically designed for older adults with serious illness who are receiving post-acute NH care.

Regulation of anti-double-stranded DNA B cells in nonautoimmune mice: localization to the T-B interface of the splenic follicle.

Systemic lupus erythematosus (SLE) and the MRL-lpr/lpr murine model for SLE are characterized by the presence of serum anti-double-stranded (ds)DNA antibodies (Abs), whereas nonautoimmune individuals have negligible levels of these Abs. To increase the frequency of anti-DNA B cells and identify the mechanisms involved in their regulation in nonautoimmune mice, we have used Ig transgenes (tgs). In the present study, we used the VH3H9 heavy (H) chain tg which expresses an H chain that was repeatedly isolated from anti-dsDNA Abs from MRL-lpr/lpr mice. Because the VH3H9 H chain can pair with endogenous L chains to generate anti-single-stranded DNA, anti-dsDNA, and non-DNA B cells, this allowed us to study the regulation of anti-dsDNA B cells in the context of a diverse B cell repertoire. We have identified anti-dsDNA B cells that are located at the T-B interface in the splenic follicle where they have an increased in vivo turnover rate. These anti-dsDNA B cells exhibit a unique surface phenotype suggesting developmental arrest due to antigen exposure.

MRL-lpr/lpr mice exhibit a defect in maintaining developmental arrest and follicular exclusion of anti-double-stranded DNA B cells.

A hallmark of systemic lupus erythematosus and the MRL murine model for lupus is the presence of anti-double-stranded (ds)DNA antibodies (Abs). To identify the steps leading to the production of these Abs in autoimmune mice, we have compared the phenotype and localization of anti-dsDNA B cells in autoimmune (MRL+/+ and lpr/lpr) mice with that in nonautoimmune (BALB/c) mice. Anti-dsDNA B cells are actively regulated in BALB/c mice as indicated by their developmental arrest and accumulation at the T-B interface of the splenic follicle. In the MRL genetic background, anti-dsDNA B cells are no longer developmentally arrested, suggesting an intrinsic B cell defect conferred by MRL background genes. With intact Fas, they continue to exhibit follicular exclusion; however, in the presence of the lpr/lpr mutation, anti-dsDNA B cells are now present in the follicle. Coincident with the altered localization of anti-dsDNA B cells is a follicular infiltration of CD4 T cells. Together, these data suggest that MRL mice are defective in maintaining the developmental arrest of autoreactive B cells and indicate a role for Fas in restricting entry into the follicle.

Hemorrhage and large lipid-rich necrotic cores are independently associated with thin or ruptured fibrous caps: an in vivo 3T MRI study.

OBJECTIVE: Histological studies suggest associations between hemorrhage and large lipid-rich/necrotic cores with thin or ruptured fibrous caps in advanced atherosclerosis. We investigated these associations in carotid arteries with mild to severe stenosis by in vivo 3T MRI. METHODS AND RESULTS: Seventy-seven patients with >or=50% carotid stenosis in at least one side by duplex ultrasound underwent bilateral multi-contrast carotid MRI scans. Measurements for wall and lipid-rich/necrotic core sizes, presence of hemorrhage, and fibrous cap status (classified as intact thick, intact thin or ruptured) were recorded. Arteries with poor image quality, occlusion, or no detectable lipid-rich/necrotic core were excluded. For the 798 MRI slices included, multivariate ordinal regression analysis demonstrated larger %lipid-rich/necrotic core (odds ratio for 10% increase, 1.49; P=0.02) and presence of hemorrhage (odds ratio, 5.91; P<0.001) were independently associated with a worse (intact thin or ruptured) stage of fibrous cap status. For artery-based multivariate analysis, a larger maximum %lipid-rich/necrotic core and presence of hemorrhage independently associated with worse fibrous cap status (P<0.001, for both). No hemorrhage was detected in arteries with thick fibrous caps. CONCLUSIONS: Hemorrhage and larger %lipid-rich/necrotic core were independently associated with a thin or ruptured fibrous cap status at an early to advanced stage of carotid atherosclerosis.

Spatial distribution of sequential ventilation during mechanical ventilation of the uninjured lung: an argument for cyclical airway collapse and expansion.

BACKGROUND: Ventilator-induced lung injury (VILI) is a recognized complication of mechanical ventilation. Although the specific mechanism by which mechanical ventilation causes lung injury remains an active area of study, the application of positive end expiratory pressure (PEEP) reduces its severity. We have previously reported that VILI is spatially heterogeneous with the most severe injury in the dorsal-caudal lung. This regional injury heterogeneity was abolished by the application of PEEP = 8 cm H2O. We hypothesized that the spatial distribution of lung injury correlates with areas in which cyclical airway collapse and recruitment occurs. METHODS: To test this hypothesis, rabbits were mechanically ventilated in the supine posture, and regional ventilation distribution was measured under four conditions: tidal volumes (VT) of 6 and 12 ml/kg with PEEP levels of 0 and 8 cm H2O. RESULTS: We found that relative ventilation was sequentially redistributed towards dorsal-caudal lung with increasing tidal volume. This sequential ventilation redistribution was abolished with the addition of PEEP. CONCLUSIONS: These results suggest that cyclical airway collapse and recruitment is regionally heterogeneous and spatially correlated with areas most susceptible to VILI.

Evaluation of otoscope cone disinfection techniques and contamination level in small animal private practice.

The objective of this study was to evaluate the level of bacterial contamination of otoscope cones in veterinary private practice, and to determine the most effective method of disinfection. Fifty small animal practices participated in this study, which included a detailed survey regarding otoscope cleaning, storage and usage and quantitative culture of the cleaned and stored otoscope cones. Using sterile technique, two cones from each of the 50 hospitals were swabbed and submitted for quantitative culture. Contamination was present in 29% of the samples and the following organisms were isolated: Flavobacterium brevis (10%), Pseudomonas aeruginosa (6%), Pseudomonas alcaligenes (4%), Staphylococcus intermedius (4%), Corynebacterium spp. (2%), Bacillus spp. (1%), Enterococcus faecalis (1%) Malassezia spp. (1%). There was no statistically significant difference between storage type (dry versus stored in solution) and for the instrumentation used to clean the cones (brush, cotton-tipped applicator, both versus none). There was a statistically significant difference between the different cleaning solutions (P < 0.001) and between the storage solutions (P = 0.003). A single most effective cleaning solution was unable to be determined due to the large number of solutions utilized. Cetylcide G (Cetylite Industries, Inc., Pennsauken, NJ, USA) was the most effective of the three most commonly used storage solutions (Cetylcide G, Benz-all, and 2% Chlorhexidine gluconate) when used as directed (P < 0.001). The level of contamination had a positive association with the frequency of cone use and a negative association with the frequency of storage solution replacement.

Cytomegalovirus-seropositivity has a profound influence on the magnitude of major lymphoid subsets within healthy individuals.

Cytomegalovirus (CMV) infects most individuals and elicits a strong CMV-specific immune response. We have studied the influence of CMV-seropositivity on the size of lymphoid subsets in healthy donors and demonstrate that the virus substantially modulates the peripheral lymphoid pool. CD8(+) T cell numbers are increased in all CMV-seropositive individuals because of a striking 60% increment in the CD8(+) T cell memory pool. The CD45RA(+) resting memory pool is doubled after CMV infection and increases further with age. The magnitude of the naïve CD8(+) T cell pool is dramatically reduced in CMV-seropositive individuals at all ages, and this accelerates the physiological decline by approximately 40 years. The number of CD4(+) effector memory T cells is increased in CMV-seropositive individuals and is differentially accommodated by a reduction in the number of naïve and central memory CD4(+) T cells in young and elderly donors respectively. CMV-seropositivity also increases the total number of B cells in older donors and suppresses the number of CD5(+) B cells. These data reveal that CMV has a profound influence on the immune system of all healthy individuals and add to growing concern regarding the clinical and immunomodulatory significance of CMV infection in healthy donors.

Regional lung blood flow and ventilation in upright humans studied with quantitative SPECT.

We used quantitative Single Photon Emission Computed Tomography (SPECT) to study the effect of the upright posture on regional lung blood flow and ventilation. Nine (upright) plus seven (prone and supine) healthy volunteers were studied awake, breathing spontaneously. Regional blood flow and ventilation were marked in sitting upright, supine and prone postures using (113m)In-labeled macroaggregates and inhaled Technegas ((99m)Tc); both remain fixed in the lung after administration. All images were obtained while supine. In comparison with horizontal postures, both blood flow and ventilation were greater in caudal regions when upright. The redistribution was greater for blood flow than for ventilation, resulting in decreasing ventilation-to-perfusion ratios down the lung when upright. We conclude that gravity redistributes regional blood flow and ventilation in the upright posture, while the influence is much less in the supine and prone postures.