Clinical Outcomes Associated With Overestimation of Oxygen Saturation by Pulse Oximetry in Patients Hospitalized With COVID-19

Importance

Many pulse oximeters have been shown to overestimate oxygen saturation in persons of color, and this phenomenon has potential clinical implications. The relationship between overestimation of oxygen saturation with timing of COVID-19 medication delivery and clinical outcomes remains unknown.

Objective

To investigate the association between overestimation of oxygen saturation by pulse oximetry and delay in administration of COVID-19 therapy, hospital length of stay, risk of hospital readmission, and in-hospital mortality.

Design, Setting, and Participants

This cohort study included patients hospitalized for COVID-19 at 186 acute care facilities in the US with at least 1 functional arterial oxygen saturation (SaO2) measurement between March 2020 and October 2021. A subset of patients were admitted after July 1, 2020, without immediate need for COVID-19 therapy based on pulse oximeter saturation (SpO2 levels of 94% or higher without supplemental oxygen).

Exposures

Self-reported race and ethnicity, difference between concurrent SaO2 and pulse oximeter saturation (SpO2) within 10 minutes, and initially unrecognized need for COVID-19 therapy (first SaO2 reading below 94% despite SpO2 levels of 94% or above).

Main Outcome and Measures

The association of race and ethnicity with degree of pulse oximeter measurement error (SpO2 - SaO2) and odds of unrecognized need for COVID-19 therapy were determined using linear mixed-effects models. Associations of initially unrecognized need for treatment with time to receipt of therapy (remdesivir or dexamethasone), in-hospital mortality, 30-day hospital readmission, and length of stay were evaluated using mixed-effects models. All models accounted for demographics, clinical characteristics, and hospital site. Effect modification by race and ethnicity was evaluated using interaction terms.

Results

Among 24 504 patients with concurrent SpO2 and SaO2 measurements (mean [SD] age, 63.9 [15.8] years; 10 263 female [41.9%]; 3922 Black [16.0%], 7895 Hispanic [32.2%], 2554 Asian, Native American or Alaskan Native, Hawaiian or Pacific Islander, or another race or ethnicity [10.4%], and 10 133 White [41.4%]), pulse oximetry overestimated SaO2 for Black (adjusted mean difference, 0.93 [95% CI, 0.74-1.12] percentage points), Hispanic (0.49 [95% CI, 0.34-0.63] percentage points), and other (0.53 [95% CI, 0.35-0.72] percentage points) patients compared with White patients. In a subset of 8635 patients with a concurrent SpO2 - SaO2 pair without immediate need for COVID-19 therapy, Black patients were significantly more likely to have pulse oximetry values that masked an indication for COVID-19 therapy compared with White patients (adjusted odds ratio [aOR], 1.65; 95% CI, 1.33-2.03). Patients with an unrecognized need for COVID-19 therapy were 10% less likely to receive COVID-19 therapy (adjusted hazard ratio, 0.90; 95% CI, 0.83-0.97) and higher odds of readmission (aOR, 2.41; 95% CI, 1.39-4.18) regardless of race (P for interaction = .45 and P = .14, respectively). There was no association of unrecognized need for COVID-19 therapy with in-hospital mortality (aOR, 0.84; 95% CI, 0.71-1.01) or length of stay (mean difference, -1.4 days; 95% CI, -3.1 to 0.2 days).

Conclusions and Relevance

In this cohort study, overestimation of oxygen saturation by pulse oximetry led to delayed delivery of COVID-19 therapy and higher probability of readmission regardless of race. Black patients were more likely to have unrecognized need for therapy with potential implications for population-level health disparities.

Thromboprophylaxis in people hospitalized with COVID-19: Assessing intermediate or standard doses in a retrospective cohort study

Background and Objectives

Current clinical guidelines recommend thromboprophylaxis for adults hospitalized with coronavirus disease 2019 (COVID-19), yet it is unknown whether higher doses of thromboprophylaxis offer benefits beyond standard doses.

Methods

We studied electronic health records from 50 091 adults hospitalized with COVID-19 in the United States between February 2020 and February 2021. We compared standard (enoxaparin 30 or 40 mg/day, fondaparinux 2.5 mg, or heparin 5000 units twice or thrice per day) versus intermediate (enoxaparin 30 or 40 mg twice daily, or up to 1.2 mg/kg of body weight daily, heparin 7500 units thrice per day or heparin 10 000 units twice or thrice per day) thromboprophylaxis. We separately examined risk of escalation to therapeutic anticoagulation, severe disease (first occurrence of high-flow nasal cannula, noninvasive positive pressure ventilation or invasive mechanical ventilation), and death. To summarize risk, we present hazard ratios (HRs) with 95% confidence intervals (CIs) using adjusted time-dependent Cox proportional hazards regression models.

Results

People whose first dose was high intensity were younger, more often obese, and had greater oxygen support requirements. Intermediate dose thromboprophylaxis was associated with increased risk of therapeutic anticoagulation (HR, 3.39; 95% CI, 3.22-3.57), severe disease (HR, 1.22; 95% CI, 1.17-1.28), and death (HR, 1.37; 95% CI, 1.21-1.55). Increased risks associated with intermediate-dose thromboprophylaxis persisted in subgroup and sensitivity analyses varying populations and definitions of exposures, outcomes, and covariates.

Conclusions

Our findings do not support routine use of intermediate-dose thromboprophylaxis to prevent clinical worsening, severe disease, or death among adults hospitalized with COVID-19.

Real-World Effectiveness Of Remdesivir In Adults Hospitalized With Covid-19: A Retrospective, Multicenter Comparative Effectiveness Study

Background

There is an urgent need to understand the real-world effectiveness of remdesivir in the treatment of SARS-CoV-2.

Methods

This was a retrospective comparative effectiveness study. Individuals hospitalized in a large private healthcare network in the US from February 23, 2020 through February 11, 2021 with a positive test for SARS-CoV-2 and ICD-10 diagnosis codes consistent with symptomatic COVID-19 were included. Remdesivir recipients were matched to controls using time-dependent propensity scores. The primary outcome was time to improvement with a secondary outcome of time to death.

Results

Of 96,859 COVID-19 patients, 42,473 (43.9%) received at least one remdesivir dose. The median age of remdesivir recipients was 65 years, 23,701 (55.8%) were male and 22,819 (53.7%) were non-white. Matches were found for 18,328 patients (43.2%). Remdesivir recipients were significantly more likely to achieve clinical improvement by 28 days (adjusted hazard ratio [1.19, 95% confidence interval (CI), 1.16-1.22]). Remdesivir patients on no oxygen (aHR 1.30, 95% CI 1.22-1.38) or low-flow oxygen (aHR 1.23, 95% CI 1.19-1.27) were significantly more likely to achieve clinical improvement by 28 days. There was no significant impact on the likelihood of mortality overall (aHR 1.02, 95% CI 0.97-1.08). Remdesivir recipients on low-flow oxygen were significantly less likely to die than controls (aHR 0.85, 95% CI 0.77-0.92; 28-day mortality 8.4% [865 deaths] for remdesivir patients, 12.5% [1,334 deaths] for controls).

Conclusions

These results support the use of remdesivir for hospitalized COVID-19 patients on no or low-flow oxygen. Routine initiation of remdesivir in more severely ill patients is unlikely to be beneficial.

Exposure to foreign gut microbiota can facilitate rapid dietary shifts

Dietary niche is fundamental for determining species ecology; thus, a detailed understanding of what drives variation in dietary niche is vital for predicting ecological shifts and could have implications for species management. Gut microbiota can be important for determining an organism’s dietary preference, and therefore which food resources they are likely to exploit. Evidence for whether the composition of the gut microbiota is plastic in response to changes in diet is mixed. Also, the extent to which dietary preference can be changed following colonisation by new gut microbiota from different species is unknown. Here, we use Drosophila spp. to show that: (1) the composition of an individual’s gut microbiota can change in response to dietary changes, and (2) ingestion of foreign gut microbes can cause individuals to be attracted to food types they previously had a strong aversion to. Thus, we expose a mechanism for facilitating rapid shifts in dietary niche over short evolutionary timescales.

Outcomes of COVID-19 in hospitalized solid organ transplant recipients compared to a matched cohort of non-transplant patients at a national healthcare system in the United States

Data describing outcomes of solid organ transplant (SOT) recipients with coronavirus disease 2019 (COVID‐19) are variable, and the association between SOT status and mortality remains unclear. In this study, we compare clinical outcomes of SOT recipients hospitalized with COVID‐19 between March 10, and September 1, 2020, to a matched cohort of non‐SOT recipients at a national healthcare system in the United States (US). From a population of 43 461 hospitalized COVID‐19‐positive patients, we created a coarsened exact matched cohort of 4035 patients including 128 SOT recipients and 3907 weighted matched non‐SOT controls. Multiple logistic regression was used to evaluate association between SOT status and clinical outcomes. Among the 4035 patients, median age was 60 years, 61.7% were male, 21.9% were Black/African American, and 50.8% identified as Hispanic/Latino ethnicity. Patients with a history of SOT were more likely to die within the study period when compared to matched non‐SOT recipients (21.9% and 14.9%, respectively; odds ratio [OR] 1.93; 95% confidence interval [CI]: 1.18–3.15). Moreover, SOT status was associated with increased odds of receiving invasive mechanical ventilation (OR [95% CI]: 2.34 [1.51–3.65]), developing acute kidney injury (OR [95% CI]: 2.41 [1.59–3.65]), and receiving vasopressor support during hospitalization (OR [95% CI]: 2.14 [1.31–3.48]).

User-centered design and usability testing of RxMAGIC: a prescription management and general inventory control system for free clinic dispensaries

BACKGROUND

To address challenges related to medication management in underserved settings, we developed a system for Prescription Management And General Inventory Control, or RxMAGIC, in collaboration with the Birmingham Free Clinic in Pittsburgh, Pennsylvania. RxMAGIC is an interoperable, web-based medication management system designed to standardize and streamline the dispensing practice and improve inventory control in a free clinic setting. This manuscript describes the processes used to design, develop, and deploy RxMAGIC.

METHODS

We transformed data from previously performed mixed-methods needs assessment studies into functional user requirements using agile development methods. Requirements took the form of user stories that were prioritized to drive implementation of RxMAGIC as a web-application. A functional prototype was developed and tested to understand its perceived usefulness before developing a production system. Prior to deployment, we evaluated the usability of RxMAGIC with six users to diagnose potential interaction challenges that may be avoided through redesign. The results from this study were similarly prioritized and informed the final features of the production system.

RESULTS

We developed 45 user stories that acted as functional requirements to incrementally build RxMAGIC. Integrating with the electronic health record at the clinic was a requirement for deployment. We utilized health data standards to communicate with the existing order entry system; an outgoing electronic prescribing framework was leveraged to send prescription data to RxMAGIC. The results of the usability study were positive, with all tested features receiving a mean score of four or five (i.e. somewhat easy or easy, respectively) on a five-point Likert scale assessing ease of completion, thus demonstrating the system's simplicity and high learnability. RxMAGIC was deployed at the clinic in October 2016 over a two-week period.

CONCLUSIONS

We built RxMAGIC, an open-source, pharmacist-facing dispensary management information system that augments the pharmacist's ability to efficiently deliver medication services in a free clinic setting. RxMAGIC provides electronic dispensing and automated inventory management and alerting capabilities. We deployed RxMAGIC at the Birmingham Free Clinic and measured its usability with potential users. In future work, we plan to continue to measure the impact of RxMAGIC on pharmacist efficiency and satisfaction.

Computer Science, Biology and Biomedical Informatics academy: Outcomes from 5 years of Immersing High-school Students into Informatics Research

The University of Pittsburgh's Department of Biomedical Informatics and Division of Pathology Informatics created a Science, Technology, Engineering, and Mathematics (STEM) pipeline in 2011 dedicated to providing cutting-edge informatics research and career preparatory experiences to a diverse group of highly motivated high-school students. In this third editorial installment describing the program, we provide a brief overview of the pipeline, report on achievements of the past scholars, and present results from self-reported assessments by the 2015 cohort of scholars. The pipeline continues to expand with the 2015 addition of the innovation internship, and the introduction of a program in 2016 aimed at offering first-time research experiences to undergraduates who are underrepresented in pathology and biomedical informatics. Achievements of program scholars include authorship of journal articles, symposium and summit presentations, and attendance at top 25 universities. All of our alumni matriculated into higher education and 90% remain in STEM majors. The 2015 high-school program had ten participating scholars who self-reported gains in confidence in their research abilities and understanding of what it means to be a scientist.

Measuring time utilization of pharmacists in the Birmingham Free Clinic dispensary

Background

Free and charitable clinics are a critical part of America’s healthcare safety net. Although informatics tools have the potential to mitigate many of the organizational and service-related challenges facing these clinics, little research attention has been paid to the workflows and potential impact of electronic systems in these settings. In previous work, we performed a qualitative investigation at a free clinic dispensary to identify workflow challenges that may be alleviated through introduction of informatics interventions. However, this earlier study did not quantify the magnitude of these challenges. Time-motion studies offer a precise standard in quantifying healthcare workers’ time expenditures on clinical activities, and can provide valuable insight into system specifications. These data, informed by a lean healthcare perspective, provide a quality improvement framework intended to maximize value and eliminate waste in inefficient workflow processes.

Methods

We performed a continuous observation time-motion study in the Birmingham Free Clinic dispensary. Two researchers followed pharmacists over the course of three general clinic sessions and recorded the duration of specific tasks. Pharmacists were then asked to identify tasks as value-added or non-value-added to facilitate calculation of the value quotient, a metric used to determine a workflow’s level of efficiency.

Results

Four high-level workflow categories occupied almost 95 % of pharmacist time: prescription (Rx) preparation (39.8 %), clinician interaction (21.5 %), EMR operations (14.8 %), and patient interaction (18.7 %). Pharmacists invested the largest portion of time in prescription preparation, with 21.8 % of pharmacist time spent handwriting medication labels. Based on value categorizations made by the pharmacists, the average value quotient was found to be 40.3 %, indicating that pharmacists spend more than half of their time completing tasks they consider to be non-value-added.

Conclusions

Our results show that pharmacists spend a large portion of their time preparing prescriptions, primarily the handwritten labeling of medication bottles and documentation tasks, which is not an optimal utilization of pharmacist expertise. The value quotient further supports that there are many wasteful tasks that may benefit from workflow redesign and health information technology, which could result in efficiency improvements for pharmacists.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-016-1787-6) contains supplementary material, which is available to authorized users.

Assessing Perceived Challenges to Laboratory Testing at a Malawian Referral Hospital

Adequate laboratory infrastructure in sub-Saharan Africa is vital for tackling the burden of infectious diseases such as human immunodeficiency virus and acquired immune deficiency syndrome, malaria, and tuberculosis, yet laboratories are ill-integrated into the diagnostic and care delivery process in low-resource settings. Although much of the literature focuses on disease-specific challenges around laboratory testing, we sought to identify horizontal challenges to the laboratory testing process through interviews with clinicians involved in the diagnostic process. Based on 22 interviews with physicians, nurses, clinical officers, medical students, and laboratory technicians, technologists and supervisors, we identified 12 distinct challenges in the areas of staff, materials, workflow, and the blood bank. These challenges underscore the informational challenges that compound more visible resource shortages in the laboratory testing process, which lend themselves to horizontal strengthening efforts around the diagnostic process.

How can we improve Science, Technology, Engineering, and Math education to encourage careers in Biomedical and Pathology Informatics?

The Computer Science, Biology, and Biomedical Informatics (CoSBBI) program was initiated in 2011 to expose the critical role of informatics in biomedicine to talented high school students.[1] By involving them in Science, Technology, Engineering, and Math (STEM) training at the high school level and providing mentorship and research opportunities throughout the formative years of their education, CoSBBI creates a research infrastructure designed to develop young informaticians. Our central premise is that the trajectory necessary to be an expert in the emerging fields of biomedical informatics and pathology informatics requires accelerated learning at an early age.In our 4^th year of CoSBBI as a part of the University of Pittsburgh Cancer Institute (UPCI) Academy (http://www.upci.upmc.edu/summeracademy/), and our 2nd year of CoSBBI as an independent informatics-based academy, we enhanced our classroom curriculum, added hands-on computer science instruction, and expanded research projects to include clinical informatics. We also conducted a qualitative evaluation of the program to identify areas that need improvement in order to achieve our goal of creating a pipeline of exceptionally well-trained applicants for both the disciplines of pathology informatics and biomedical informatics in the era of big data and personalized medicine.

Understanding the dispensary workflow at the Birmingham Free Clinic: a proposed framework for an informatics intervention

Background

The Birmingham Free Clinic (BFC) in Pittsburgh, Pennsylvania, USA is a free, walk-in clinic that serves medically uninsured populations through the use of volunteer health care providers and an on-site medication dispensary. The introduction of an electronic medical record (EMR) has improved several aspects of clinic workflow. However, pharmacists’ tasks involving medication management and dispensing have become more challenging since EMR implementation due to its inability to support workflows between the medical and pharmaceutical services. To inform the design of a systematic intervention, we conducted a needs assessment study to identify workflow challenges and process inefficiencies in the dispensary.

Methods

We used contextual inquiry to document the dispensary workflow and facilitate identification of critical aspects of intervention design specific to the user. Pharmacists were observed according to contextual inquiry guidelines. Graphical models were produced to aid data and process visualization. We created a list of themes describing workflow challenges and asked the pharmacists to rank them in order of significance to narrow the scope of intervention design.

Results

Three pharmacists were observed at the BFC. Observer notes were documented and analyzed to produce 13 themes outlining the primary challenges pharmacists encounter during dispensation at the BFC. The dispensary workflow is labor intensive, redundant, and inefficient when integrated with the clinical service. Observations identified inefficiencies that may benefit from the introduction of informatics interventions including: medication labeling, insufficient process notification, triple documentation, and inventory control.

Conclusions

We propose a system for Prescription Management and General Inventory Control (RxMAGIC). RxMAGIC is a framework designed to mitigate workflow challenges and improve the processes of medication management and inventory control. While RxMAGIC is described in the context of the BFC dispensary, we believe it will be generalizable to pharmacies in other low-resource settings, both domestically and internationally.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-016-1308-7) contains supplementary material, which is available to authorized users.

Influence of transducer frequency and imaging modality on the intraoperative assessment of myocardial perfusion with transesophageal echocardiography

OBJECTIVE

To determine factors that improve intraoperative myocardial perfusion assessment with conventional ultrasound imaging and intravenous ultrasound agents.

DESIGN

Prospective cohort study with repeated interventions on each patient.

SETTING

Single university hospital.

PARTICIPANTS

Fourteen patients scheduled for elective coronary artery bypass graft surgery.

INTERVENTIONS

Myocardial perfusion was evaluated with contrast transesophageal echocardiography during conventional imaging after central venous injections of the contrast agent Optison (0.3 mL) before cardiopulmonary bypass. Eight patients received the injection during continuous sampling at each of 4 transducer frequency settings (3.5, 5.0, 6.0, 7.0 MHz). In another 6 patients, injections were administered during continuous and intermittent sampling (electrocardiogram-gated) at 3.5 and 5.0 MHz. Generalized estimating equations were used to compare mean responses, with p < or = 0.05 considered significant.

MEASUREMENTS AND MAIN RESULTS

All recorded images were analyzed with off-line videodensitometry. Background-corrected peak pixel intensity (PPI(corr)) and rate of change in pixel intensity (PPI(corr)/T(PPI)) were determined for each injection. PPI(corr) was greater at 3.5 MHz than at 5.0, 6.0, and 7.0 MHz (p < 0.001). PPI(corr)/T(PPI) was greater at 3.5 MHz than at 5.0 (p < 0.001), 6.0 (p = 0.003), and 7.0 MHz (p < 0.001). PPI(corr) was greater for gated than for nongated sampling conditions at 3.5 (p < 0.05) and 5.0 MHz (p < 0.05).

CONCLUSION

To optimize myocardial contrast opacification, intraoperative transesophageal echocardiography should be performed with intermittent sampling at a transducer frequency close to the intrinsic frequency of the contrast agent.

Photodynamic therapy-mediated oxidative stress as a molecular switch for the temporal expression of genes ligated to the human heat shock promoter

Oxidative stress associated with photodynamic therapy (PDT) is a transcriptional inducer of genes encoding stress proteins, including those belonging to the heat shock protein (hsp) family. The efficiency of PDT to function as a molecular switch by initiating expression of heterologous genes ligated to the human hsp promoter was examined in the present study. Selective and temporal reporter gene expression was documented after PDT in mouse radiation-induced fibrosarcoma cells stably transfected with recombinant vectors containing an hsp promoter ligated to either the lac-z or CAT reporter genes and in transfected radiation-induced fibrosarcoma tumors grown in C3H mice. Hyperthermia treatments were included as a positive control for all experiments. Expression vectors containing either human p53 or tumor necrosis factor (TNF)-alpha cDNA under the control of an hsp promoter were also constructed and evaluated. A p53 null and TNF-alpha-resistant human ovarian carcinoma (SKOV-3) cell line was stably transfected with either the p53 or TNF-alpha constructs. Inducible expression and function of p53 as well as inducible expression, secretion, and biological activity of TNF-alpha were documented after PDT or hyperthermia in transfected SKOV cells. These results demonstrate that PDT-mediated oxidative stress can function as a molecular switch for the selective and temporal expression of heterologous genes in tumor cells containing expression vectors under the control of an hsp promoter.

Further data on the structure of brown seaweed fucans: relationships with anticoagulant activity

The composition, molecular weight (MW), anticoagulant activity and nuclear magnetic resonance spectra of various low-molecular-weight fucans (LMWFs) obtained by partial hydrolysis or radical depolymerization of a crude fucoidan extracted from the brown seaweed Ascophyllum nodosum are compared. Fucose units were found mainly sulfated at O-2, to a lesser extent at O-3, and only slightly at O-4, contrary to previously published results for fucoidans from other brown seaweeds, and fucose 2, 3-O-disulfate residues were observed for the first time. As the sulfation pattern excluded an alpha-(1-->2)-linked fucose backbone and a high proportion of alpha-(1-->4) linkages was found, it would appear that the concept of fucoidan structure needs to be revised. Anticoagulant activity is apparently related not only to MW and sulfation content, as previously determined, but also (and more precisely) to 2-O-sulfation and 2,3-O-disulfation levels.

Spiral CT of acute pulmonary thromboembolism: evaluation of pleuroparenchymal abnormalities

PURPOSE

The goal of this work was to identify and categorize the spectrum of pulmonary parenchymal and pleural abnormalities identified by CT in patients with acute pulmonary thromboembolism (PE).

METHOD

A review of interpretations from 4,715 consecutive contrast-enhanced thoracic CT studies identified 41 examinations in which the diagnosis of PE was reported. Thirty-four studies were available for review, and two radiologists confirmed intraluminal defects in 31 patients. The number of emboli were counted and localized using bronchopulmonary nomenclature. Associated parenchymal and pleural abnormalities were tabulated.

RESULTS

Of the 31 patients, 13 underwent confirmatory or correlative studies including angiography, radionuclide study, or autopsy. In addition, deep venous thrombosis was confirmed by ultrasound or MRI in 13 patients. An average of 7.5 emboli per patient was detected. Pleuroparenchymal findings were as follows: Nine patients (29%) had no acute pulmonary parenchymal or pleural abnormality. In the remaining 22 patients, pleural effusion was the most common abnormality, found in 14 of 31 (45%). Ten patients (32%) had peripheral wedge-shaped parenchymal opacities suggestive of pulmonary infarction. Normally enhancing lobar atelectasis was seen in nine patients (29%). Six patients (19%) demonstrated heterogeneous parenchymal enhancement within nonaerated lung, two of whom had pathologically proven pulmonary infarct. Thirteen of 31 patients underwent high resolution CT; a typical mosaic perfusion pattern was seen in only 1 patient.

CONCLUSION

Twenty-nine percent of patients with acute PE had no acute lung parenchymal abnormality on CT; thus, the absence of parenchymal abnormality on CT does not exclude PE. High resolution CT mosaic perfusion was not a common feature of acute pulmonary embolism. Regions of decreased enhancement within nonaerated lung, seen in 19%, may prove to be an indicator of pulmonary infarction; however, this is a nonspecific finding.

Photodynamic therapy sensitivity is not altered in human tumor cells after abrogation of p53 function

Photodynamic therapy (PDT) is an effective local cancer treatment that induces cytotoxicity through the intracellular generation of reactive oxygen species. The current study investigated whether abrogation of wild-type p53 expression modified the sensitivity of tumor cells to PDT-mediated oxidative stress. In these experiments, human colon (LS513) and breast (MCF-7) carcinoma cells exhibiting a wild-type p53 phenotype were directly compared to LS513 and MCF-7 cells with abrogated p53 function induced by stable integration of the human papillomavirus type 16 E6 viral oncoprotein. The effectiveness of this viral oncoprotein to target p53 for degradation was confirmed using a p53 transactivation reporter gene assay. Western analysis also confirmed attenuated expression of p53 in E6-transfected cells. Photosensitivity of PDT-treated cells was measured by a clonogenic assay and found to be equivalent for parental and p53-abrogated cells. PDT-mediated oxidative stress resulted in a rapid shift of pRb from a hyperphosphorylated form to a predominantly underphosphorylated form in parental cells that was not preceded by increases in p53 or p21 expression. Hypophosphorylated pRb was also observed in PDT-treated LS513/E6 and MCF-7/E6 cells, further indicating that p53 was not involved in this process. Delayed expression of p53 and p21 proteins was seen in parental cells 24-48 h after photosensitization. Cell cycle analysis showed that the abrogation of p53 had minimal effects on an observed PDT-induced G1 block. Rapid induction of apoptosis was documented in PDT-treated LS513 cells, whereas LS513/E6 treated cells exhibited reduced apoptosis in response to PDT. The MCF-7 cell lines exhibited a minimal apoptotic response to PDT. These results indicate that p53 expression does not directly modulate tumor cell sensitivity to PDT in either apoptosis-responsive (LS513) or nonresponsive (MCF-7) cells.

Increased soft-tissue blood flow in patients with reflex sympathetic dystrophy of the lower extremity revealed by power Doppler sonography

OBJECTIVE

We evaluated the ability of power Doppler sonography to show increased soft-tissue blood flow in patients with reflex sympathetic dystrophy of the lower extremity.

SUBJECTS AND METHODS

Power Doppler sonography was performed in 30 patients with reflex sympathetic dystrophy of the lower extremity and in 26 asymptomatic control subjects. The bilateral power Doppler sonograms that were obtained of the soft tissues of the dorsum of the foot of each subject were grouped in pairs, and three sonologists who were unaware of clinical information independently reviewed the images. Images were evaluated for the amount of power Doppler signal shown on the following scale: 1 = no flow or minimal flow; 2 = mild flow; 3 = moderate flow; and 4 = marked flow.

RESULTS

More power Doppler flow was seen in the patients with reflex sympathetic dystrophy than in the control subjects (p < .005). In addition, side-to-side asymmetry of flow was seen in patients, but this trend was not statistically significant (p < .20). Receiver operating characteristic (ROC) analysis showed that combined flow and asymmetry were more related to reflex sympathetic dystrophy than either parameter alone (area under the ROC curve: for flow, 0.748; for asymmetry, 0.566; for both, 0.799). We found that when the sum of power Doppler flow in both feet was greater than or equal to five, and asymmetry of flow was greater than or equal to one, the sensitivity of power Doppler sonography for reflex sympathetic dystrophy was 73% and the specificity was 92%.

CONCLUSION

Patients with reflex sympathetic dystrophy of the lower extremity have increased power Doppler flow compared with asymptomatic control subjects. Patients may also exhibit more side-to-side asymmetry of flow than control subjects.

A familial case of X chromosome deletion ascertained by cytogenetic screening of women with premature ovarian failure

The association between X chromosome deletions and premature ovarian failure is well established. Previous anecdotal reports however, have not documented the prevalence of X deletions in women with premature ovarian failure. We therefore performed cytogenetic analyses on 79 women with primary or secondary amenorrhoea to assess the utility of screening for a genetic marker for familial premature ovarian failure. A normal karyotype was found in 77 women. One woman with primary amenorrhoea had an XY karyotype and a woman with secondary amenorrhoea had a deletion at Xq 26.1. This second case had a family history of premature ovarian failure, and her mother who underwent premature ovarian failure at 28 years shared this deletion. The early diagnosis of familial X deletions causing premature ovarian failure allowed for the prediction of impending menopause and the implementation of manoeuvres to advance conception. Although cytogenetic aberrations are rare in secondary amenorrhoea, the ability to predict premature ovarian failure can be vital.

Distal 6p deletion syndrome: a report of a case with anterior chamber eye anomaly and review of published reports

We describe a 32 year old male with a distal 6p24.3-->pter deletion. He has specific developmental anomalies of the anterior chamber of the eye and a cleft uvula which is consistent with the recent localisation of genes for iris development and orofacial clefting to distal 6p. In addition he has progressive sensorineural deafness and this may localise a gene for deafness to this region. We conclude that a refined distal 6p deletion syndrome exists and includes a characteristic facial appearance with hypertelorism, downward slanting palpebral fissures, tented mouth, smooth philtrum, palatal malformation, ear anomalies, anterior chamber eye defects, progressive sensorineural deafness, cardiac defects, abdominal herniae, small external genitalia, and motor and speech delay.

Preventing lead poisoning and its consequences

The harmful effects of lead poisoning have been clearly espoused in the literature. All health care providers should be aware of these dangers and of current recommendations for screening for lead poisoning risks and follow-up of blood lead levels. Health education is an important aspect of health care. Pediatric nurses need to understand the hazards of lead poisoning, screening and follow-up recommendations, and have information about lead poisoning and abatement procedures available to families.

Differential photosensitivity in wild-type and mutant p53 human colon carcinoma cell lines

Tumor sensitivity to cancer therapies may be modulated by the p53 status of the malignant cells. Generally, tumors retaining wild-type p53 are more sensitive to radiotherapy and some chemotherapeutic agents than are tumors with either a mutated or deleted p53 phenotype. The role of p53 in the responsiveness to PDT as a cancer treatment is clinically unknown. In the current study, we evaluated the photosensitivity of two human colon carcinoma cell lines, one expressing wild-type p53 protein and the other expressing mutant p53. Wild-type p53 cells were found to be significantly more sensitive to Photofrin-mediated photodynamic treatment measured by clonogenic assay. Uptake of the photosensitizer was equivalent for both cell lines. Interestingly, sensitivity of the colon carcinoma cell lines to ionizing radiation was similar. These two cell lines represent a useful model for examining p53 involvement in the cellular response to PDT-mediated oxidative stress.

Inv(10)(p11.2q21.2), a variant chromosome

We present 33 families in which a pericentric inversion of chromosome 10 is segregating. In addition, we summarise the data on 32 families in which an apparently identical inv(10) has been reported in the literature. Ascertainment was through prenatal diagnosis or with a normal phenotype in 21/33 families. In the other 12 families, probands were ascertained through a wide variety of referral reasons but in all but one case (a stillbirth), studies of the family showed that the reason for referral was unrelated to the chromosome abnormality. There has been, to our knowledge, no recorded instance of a recombinant chromosome 10 arising from this inversion and no excess of infertility or spontaneous abortion among carriers of either sex. We propose that inv(10)(p11.2q21.2) can be regarded as a variant analogous to the pericentric inversion of chromosome 2(p11q13). We conclude that prenatal chromosome analysis is not justified for inv(10) carriers. In addition, family investigation of carrier status is not warranted in view of the unnecessary concern this may cause parents and other family members.

Centromeric inactivation in a dicentric human Y;21 translocation chromosome

A de novo dicentric Y;21 (q11.23;p11) translocation chromosome with one of its two centromeres inactive has provided the opportunity to study the relationship between centromeric inactivation, the organization of alphoid satellite DNA and the distribution of CENP-C. The proband, a male with minor features of Down's syndrome, had a major cell line with 45 chromosomes including a single copy of the translocation chromosome, and a minor one with 46 chromosomes including two copies of the translocation chromosome and hence effectively trisomic for the long arm of chromosome 21. Centromeric activity as defined by the primary constriction was variable: in most cells with a single copy of the Y;21 chromosome, the Y centromere was inactive. In the cells with two copies, one copy had an active Y centromere (chromosome 21 centromere inactive) and the other had an inactive Y centromere (chromosome 21 centromere active). Three different partial deletions of the Y alphoid array were found in skin fibroblasts and one of these was also present in blood. Clones of single cell origin from fibroblast cultures were analysed both for their primary constriction and to characterise their alphoid array. The results indicate that (1) each clone showed a fixed pattern of centromeric activity; (2) the alphoid array size was stable within a clone; and (3) inactivation of the Y centromere was associated with both full-sized and deleted alphoid arrays. Selected clones were analysed with antibodies to CENP-C, and staining was undetectable at both intact and deleted arrays of the inactive Y centromeres. Thus centromeric inactivation appears to be largely an epigenetic event.

Increased photosensitivity in HL60 cells expressing wild-type p53

Loss of p53 function has been correlated with decreased sensitivity to chemotherapy and radiation therapy in a variety of human tumors. Comparable analysis of p53 status with sensitivity to oxidative stress induced by photodynamic therapy has not been reported. In the current study we examined photosensitivity in human promyelocytic leukemia HL60 cells exhibiting either wild-type p53, mutated p53 or deleted p53 expression. Experiments were performed using a purpurin, tin ethyl etiopurpurin (SnET2)-, or a porphyrin, Photofrin (PH)-based photosensitizer. Total SnET2 accumulation was comparable in all three cell lines. Uptake of PH was highest in cells expressing wild-type p53 but incubation conditions could be adjusted to achieve equivalent cellular PH levels during experiments that analyzed photosensitivity. Survival measurements demonstrated that HL60 cells expressing wild-type p53 were more sensitive to PH- and SnET2-mediated photosensitization, as well as to UVC irradiation, when compared to HL60 cells exhibiting deleted or mutated p53 phenotypes. A rapid apoptotic response was observed following purpurin- and porphyrin-induced photosensitization in all cell lines. Results of this study indicate that photosensitivity is increased in HL60 cells expressing wild-type p53 and that photosensitizer-mediated oxidative stress can induce apoptosis through a p53-independent mechanism in HL60 cells.

MR imaging in male infertility

In patients with male infertility, endorectal magnetic resonance (MR) imaging provides high-resolution images of the prostate gland and ejaculatory apparatus. The multiplanar capability of MR imaging allows production of a detailed map of the reproductive tract for guiding treatment. Causes of male infertility can be classified as congenital, acquired, infectious, or hormonal. Wolffian duct abnormalities include agenesis of the kidney, vas deferens, or seminal vesicle and cysts of the vas deferens, seminal vesicle, or urogenital sinus-ejaculatory duct. Müllerian duct abnormalities are less common and consist of müllerian duct cysts and utricle cysts. Cowper duct cysts and peripheral-zone prostatic cysts are acquired causes of male infertility. Prostatitis, an infectious cause of male infertility, may mimic carcinoma on long repetition time/echo time images. A low testosterone levels is one of the hormonal causes of male infertility. Pitfalls in the interpretation of MR images can be avoided by familiarity with normal and abnormal findings in patients with male infertility.

RDCI, the vasoactive intestinal peptide receptor: a candidate gene for the features of Albright hereditary osteodystrophy associated with deletion of 2q37

Albright hereditary osteodystrophy (AHO) is an autosomal dominant disorder characterised by the presence of brachymetaphalangism, short stature, obesity, and mental retardation. Variable biochemical changes many represent either pseudohypoparathyroidism (PHP) owing to resistance to parathormone (PTH) or pseudopseudohypoparathyroidism (PPHP) with no hormone resistance. In most cases of AHO, reduced levels of Gs alpha have been found and a number of deactivating mutations in the gene for Gs alpha located on chromosome 20q13 have been described. Recently a number of people with an AHO-like phenotype have been reported in whom a deletion of chromosomal region 2q37 has been found in the absence of biochemical abnormalities or a reduction in Gs alpha activity. We present a further female patient with a cytogenetically visible deletion of 2q37, an AHO-like phenotype, and unusual biochemistry suggesting moderate PTH resistance. The vasoactive intestinal peptide receptor (RDCI) has recently been mapped to 2q37 and we propose that this is a candidate gene, hemizygosity of which affects signal transduction and leads to the AHO-like phenotype found in patients with 2q37 deletions.

Cellular targets and molecular responses associated with photodynamic therapy

The positive clinical results associated with photodynamic therapy (PDT) have led to an expanded need to identify the cellular targets and molecular responses associated with this treatment. Increased knowledge regarding the mechanisms of action associated with PDT-mediated cytotoxicity should contribute to the continued advancement of this therapy. This report focuses on recent studies analyzing PDT resistance and examining stress protein and early response gene activation induced by photosensitizer mediated oxidative stress. Recurring observations from these studies indicate that subcellular targets and cellular responses associated with PDT can vary significantly for different photosensitizers.

Rapid in situ harvesting and cytogenetic analysis of perinatal tissue samples

Thirty perinatal solid tissue samples were used in a pilot study to test the efficacy of collagenase disaggregation onto coverslips, open system culture under low O2 conditions, pre-harvest incubation in bromodeoxyuridine (BrdU) and colcemid, and in situ automated harvesting. Following the success of the pilot study, the new method was applied to a further 126 consecutive diagnostic samples making a total of 156. The method reduced average tissue culture times from 17 to 8.7 days (range 2-17), improved success rates from 76 to 88 per cent, and simultaneously increased the resolution of cytogenetic analysis.

Photodynamic therapy-mediated oxidative stress can induce expression of heat shock proteins

Photodynamic therapy (PDT) is an experimental cancer therapy inducing tumor tissue damage via photosensitizer-mediated oxidative cytotoxicity. A previous report indicates that oxidative stress induced by hydrogen peroxide or menadione activates the heat shock transcription factor in mouse cells but does not result in either increased transcription or translation of heat shock proteins (HSPs). Our study documents that photosensitizer-mediated oxidative stress can activate the heat shock factor as well as increase HSP-70 mRNA and protein levels in mouse RIF-1 cells. The cellular heat shock response after PDT varied for the different photosensitizers being examined. Treatments using either a chlorin (mono-L-aspartyl chlorin-e6)- or purpurin (tin etio-purpurin)-based sensitizer induced HSP-70 expression, whereas identical photosensitization conditions with a porphyrin (Photofrin)-based sensitizer failed to induce a cellular HSP response. These sensitizers, which generate singlet oxygen as the primary oxidant during photosensitization, were used in experiments under isoeffective treatment conditions. HSP-70 expression after photosensitization was associated with the concomitant induction of thermotolerance in PDT-treated cells. Interestingly, reverse transcription-PCR demonstrated that in vivo PDT treatments of RIF-1 tumors induce expression of HSP-70 for all photosensitizers including Photofrin. These results indicate that photosensitizer-generated singlet oxygen exposure can induce in vitro and in vivo HSP-70 expression, and that specific subcellular targets of PDT (which can differ for various sensitizers) are determinants for HSP-70 activation after oxidative stress.

Clinical and preclinical photodynamic therapy

Photodynamic therapy (PDT) is a treatment modality that utilizes a photosensitizing drug activated by laser generated light, and is proving effective for oncologic and nononcologic applications. This report provides an overview of photosensitizers, photochemistry, photobiology, and the lasers involved in photodynamic therapy. Clinical and preclinical PDT studies involving Photofrin and various second generation photosensitizers are reviewed.

Small terminal deletions of the long arm of chromosome 2: two new cases

We report on 2 girls with small de novo terminal deletions of the long arm of chromosome 2 and breakpoints within q37. Four cases with similar or more extensive deletions have been previously reported in full. Hypotonia and psychomotor retardation were the only manifestations common to all 6 cases. The phenotype associated with small terminal 2q deletions is variable and clearly not always as mild as indicated in previous reports. The abnormality may also be more common than has been assumed.

Cycle abnormalities in infertile women with regular menstrual cycles: effects of clomiphene citrate treatment

OBJECTIVE

To investigate the incidence and nature of cycle abnormalities and the effect of clomiphene citrate (CC) treatment in women with apparently ovulatory cycles and unexplained infertility.

DESIGN

Nonrandomized, open study of patients before and during treatment.

SETTING

The Reproductive Medicine Clinic of a District General Hospital.

PATIENTS

Thirty-five women with regular, apparently ovulatory menstrual cycles and unexplained infertility.

INTERVENTIONS

Detailed ultrasound and hormonal cycle tracking was performed before and during treatment with CC.

MAIN OUTCOME MEASURES

Serial ultrasound scans and measurements of serum LH, FSH, E2, and P.

RESULTS

Before treatment, 54% of cycles were uniovulatory, 40% were characterized by cyst formation, and 6% were characterized by poor follicular growth. Fifty-one percent of pretreatment cycles had normal hormone profiles, 31% had defective luteal phases, 14% had increased early follicular phase serum FSH levels, and 9% had increased early follicular phase serum LH levels. Treatment with CC reduced the incidence of cyst formation to 9% and the incidence of luteal phase defects to 3%. However, 28% of CC-treated cycles showed ultrasound features of overstimulation and 51% had high follicular phase E2 peaks so that only 34% of CC-treated cycles had normal hormone profiles.

CONCLUSIONS

Cycle abnormalities are common in unexplained infertility. The incidence of cyst formation and luteal phase defects, the most common abnormalities in this group, is reduced by CC treatment.

Incidence of circulating cells positive for GpIb and GpIIIa in infants with Down's syndrome

Blood samples from 43 infants with Down's syndrome and from 67 with a normal karyotype were screened for the presence of cells positive for platelet glycoproteins GpIb and GpIIIa. There was 1 case of fatal leukaemia and 1 case of transient leukaemia among the Down's syndrome patients, both cases had increased numbers of circulating blood cells positive for platelet glycoprotein markers. These cells were present in small numbers in both the Down's and control groups, especially among stillbirths, and there was no difference in the numbers of such cells found in Down's syndrome patients in comparison with the controls.

A cost-effectiveness analysis of an in-house corporate occupational medical department

There is a current trend for corporations to switch from in-house medical departments to outside contract organizations for provision of occupational health services. Although this may be driven by a desire to reduce expenses, there is little objective data on which to base this decision. This study compares the costs to a corporation of an in-house medical department with the costs for the same services if rendered by outside providers. Costs of the in-house department were obtained from company records. Prevailing charges for outside provider services were determined by an invoice survey and from other sources. We found that the cost for the in-house medical department was 42% less than that of the outside providers at the prevailing rates. Thus, the in-house medical department is more cost-effective than the outside providers. We also discuss other advantages of an in-house department that are more difficult to quantify.

Adriamycin resistance in Chinese hamster fibroblasts following oxidative stress induced by photodynamic therapy

Photodynamic therapy (PDT) generates reactive oxygen species that are responsible for the initial cytotoxic events produced by this treatment. An extended (16 h) porphyrin incubation prior to light irradiation increased expression of the 75, 78 and 94 kDa glucose-regulated stress proteins (GRP), as well as the cognate form of the 70 kDa heat shock protein. However, these stress proteins were not induced following isoeffective PDT doses using a short (1 h) porphyrin incubation protocol. In the current study, Chinese hamster fibroblasts were used to examine sensitivity to adjunctive PDT and adriamycin as previous reports indicate a correlation between stress protein synthesis and a decrease in adriamycin cytotoxicity. Treatments that either induced GRP (i.e. PDT with an extended porphyrin incubation or exposure to the calcium ionophore A23187) or did not induce GRP (i.e. PDT with a short porphyrin incubation or UV irradiation) were followed at increasing time intervals with a 1 h adriamycin incubation. A time-dependent decrease in adriamycin cytotoxicity was observed when cells were first exposed to either of the PDT protocols or to A23187. Alterations in intracellular drug levels did not account for the change in adriamycin sensitivity. Likewise, intracellular glutathione concentrations and antioxidant enzyme activities were not significantly altered following PDT or A23187. Parameters associated with altered adriamycin sensitivity included a decrease in the percentage of S phase cells following PDT and A23187 as well as a depletion of intracellular ATP after PDT using the extended porphyrin incubation. These results demonstrate that PDT can be added to the growing list of diverse stresses producing transient resistance to adriamycin and that stress protein induction is not universally associated with all oxidative treatments inducing this resistance.

Mosaic tetrasomy 8p: molecular cytogenetic confirmation and measurement of glutathione reductase and tissue plasminogen activator levels

We report the case of a 5-year-old girl with severe developmental disabilities, skeletal anomalies, hypotonia, rectal atresia, malrotation of the intestine, horseshoe kidney, vesicoureteric reflux, and minor facial anomalies. Conventional cytogenetic techniques suggested that she had a mosaic 46,XX/47,XX,+i(8p) constitution, and the identity of the isochromosome was confirmed by in situ hybridization and chromosome painting. Polymorphic DNA markers are consistent with the i(8p) having arisen as the result of a segregation error and centromere misdivision at the second maternal meiotic division. The i(8p) was seen in 17/25 (68%) lymphocytes at the age of one month but had declined to 31/100 (31%) cells by the age of 5 years. At this time the i(8p) was seen in 30/68 (44%) cultured skin fibroblasts. The proposita had an approximately twofold increase in red cell glutathione reductase activity but a normal level of tissue-plasminogen activator. These enzyme results are consistent with the known localisation of the glutathione reductase gene on the short arm of chromosome 8 but suggest that the tissue-plasminogen activator gene may map outside this region.

Three patients with ring (X) chromosomes and a severe phenotype

Three patients with mosaicism and a cell line containing a small ring (X) chromosome are described. Their phenotype is similar to several previously reported patients with a 45,X/46,X,r(X) karyotype and a phenotype far more severely affected than expected in Turner's syndrome. The clinical picture includes mental retardation, a facial appearance reminiscent of the Kabuki make up syndrome, and limb anomalies. Some of the patients also had streaky hyperpigmentation of the skin in a pattern suggesting dermal mosaicism. It has been hypothesised that the severe phenotype might be the result of the small r(X) chromosome remaining active. However, there is little critical evidence to support this suggestion, while there is considerable evidence against it, including (1) a similar phenotype in 45,X/46,X,r(Y) patients, (2) the late replication of some of the small r(X) chromosomes associated with this phenotype, and (3) the expression of XIST in some of the affected patients.

Restricted alpha/beta receptor gene usage of idiotype-specific major histocompatibility complex-restricted T cells: selection for CDR3-related sequences

We have sequenced the T cell receptor (TcR) V alpha and V beta genes of seven independent BALB/c CD4+ T cell clones specific for the immunoglobulin lambda 2 light chain produced by the MOPC 315 myeloma (lambda 2(315)). All the clones recognize a peptide of residues 91-101 of lambda 2(315) and are restricted by the major histocompatibility complex (MHC) molecule I-E(d). The results indicate that in BALB/c mice, this anti-idiotypic response uses a very limited number of TcR. The four clones which cross-react between Phe94 and Tyr94 peptide analogues use very similar receptors (V alpha 3, J alpha 1, V beta 6, J beta 1.1). The V alpha 3 gene used by all of these clones is identical and has not been previously described. Although the four clones differ in nucleotide sequence in the V/J borders, two had identical receptors at the amino acid level. One of the cross-reactive clones exhibits a heteroclitic response to the Tyr94 peptide variant resulting from a single amino acid exchange in the V/J junction of the alpha chain. The three remaining clones which recognize only the Phe94 and not the Tyr94 peptide have somewhat more diverse TcR, however, two of these three clones use V beta 6. One of these non-crossreacting clones is alloreactive, the specificity of which can be attributed to differences in the N-D-J sequences. Taken together these data indicate that this T cell response to an immunoglobulin idiotope is very restricted in terms of the TcR used. These data in conjunction with recently published results indicate that, although there can be strong preference for individual V alpha or V beta gene segments, certain V alpha/V beta combinations are preferentially selected for interacting with a given peptide/MHC combination, and that the CDR3-related regions are crucial for antigen fine specificity and alloreactivity.