Exploring South Asian women's perspectives and experiences of maternity care services: A qualitative evidence synthesis

BACKGROUND

The United Nations Women and other sources have highlighted the poor maternal and neonatal care experienced by South Asian women, emphasizing the need to understand the cultural factors and specific experiences that influence their health-seeking behavior. This understanding is crucial for achieving health equity and improving health outcomes for women and infants.

OBJECTIVES

This study aims to examine and synthesize qualitative evidence on the perspectives and experiences of South Asian women regarding maternity care services in destination countries.

METHODS

A systematic review was conducted using the Joanna Briggs Institute's approach. Eight databases were searched for studies capturing the qualitative views and experiences of South Asian women - Medline, EMBASE, CINAHL Plus, Global Health, Scopus, PsycInfo, British Nursing Index and the Applied Social Science Index and Abstracts. Qualitative and mixed method studies written in English are included. The methodological quality of the included studies was assessed using the JBI's QARI checklist for qualitative studies and the MMAT checklist for mixed-methods studies.

RESULTS

Fourteen studies, including twelve qualitative and two mixed-methods studies, were identified and found to be of high methodological quality. The overarching theme that emerged was "navigating cross-cultural maternity care experiences." This theme encapsulates the challenges and complexities faced by South Asian women in destination countries, including ethnocultural and religious differences, communication and language barriers, understanding different medical systems, and the impact of migration on their maternity care experiences.

CONCLUSIONS

South Asian migrant women often have expectations that differ from the services provided in destination countries, leading to challenges in their social relationships. Communication and language barriers pose additional obstacles that can be addressed through strategies promoting better communication and culturally sensitive care. To enhance the utilization of maternity healthcare services, it is important to address these factors and provide personalized, culturally sensitive care for South Asian migrant women.

Feasibility and Acceptability of an Online WhatsApp Support Group on Breastfeeding: Protocol for a Randomized Controlled Trial

Background

Mobile health, the use of mobile technology in delivering health care, has been found to be effective in changing health behaviors, including improving breastfeeding practices in postpartum women. With the widespread use of smartphones and instant messaging apps in Hong Kong, instant messaging groups could be a useful channel for delivering breastfeeding peer support.

Objective

The aim of this paper is to study the feasibility and acceptability of an online instant messaging peer support group by trained peer counselors on improving breastfeeding outcome in primiparous women in Hong Kong.

Methods

A two-arm, assessor-blind, randomized controlled feasibility study will be conducted on 40 primiparous women with the intention to breastfeed. Participants are recruited from the antenatal obstetrics and gynecology clinic of a public hospital in Hong Kong and randomly assigned at a 1:1 ratio to either intervention or control group. The intervention group receives peer support in an online instant messaging group with trained peer counselors on top of standard care, whereas the control group receives standard care. Breastfeeding outcome will be assessed for 6 months post partum or until weaned. The breastfeeding status, the proportion and duration of exclusive and any breastfeeding in each group, and the self-efficacy and attitude of participants will be assessed. The feasibility and acceptability of the study would also be assessed in preparation for a full randomized controlled trial.

Results

This study (protocol version 1 dated January 5, 2021) has been reviewed and approved by the institutional review board of the University of Hong Kong, Hospital Authority Hong Kong West Cluster (reference UW 21-039), on January 26, 2021. Data collection is ongoing and expected to be completed in December 2021. The findings will be updated on clinical trial registry and disseminated in peer-reviewed journals.

Conclusions

This study aims to assess the feasibility and effectiveness of an online instant messaging peer support group in improving the breastfeeding outcome of primiparous women in Hong Kong. Its findings could inform the feasibility of a full-scale trial with this intervention design.

Trial Registration

ClinicalTrials.gov NCT04826796; https://clinicaltrials.gov/ct2/show/NCT04826796

International Registered Report Identifier (IRRID)

DERR1-10.2196/32338

Psychometric Evaluation of a Fear of COVID-19 Scale in China: Cross-sectional Study

BACKGROUND

At the very beginning of the COVID-19 pandemic, information about fear of COVID-19 was very limited in Chinese populations, and there was no standardized and validated scale to measure the fear associated with the pandemic.

OBJECTIVE

This cross-sectional study aimed to adapt and validate a fear scale to determine the levels of fear of COVID-19 among the general population in mainland China and Hong Kong.

METHODS

A web-based questionnaire platform was developed for data collection; the study instruments were an adapted version of the 8-item Breast Cancer Fear Scale ("Fear Scale") and the 4-item Patient Health Questionnaire. The internal construct validity, convergent validity, known group validity, and reliability of the adapted Fear Scale were assessed, and descriptive statistics were used to summarize the participants' fear levels.

RESULTS

A total of 2822 study participants aged 18 years or older were included in the analysis. The reliability of the adapted scale was satisfactory, with a Cronbach α coefficient of .93. The item-total correlations corrected for overlap were >0.4, confirming their internal construct validity. Regarding convergent validity, a small-to-moderate correlation between the Fear Scale and the 4-item Patient Health Questionnaire scores was found. Regarding known group validity, we found that the study participants who were recruited from Hong Kong had a higher level of fear than the study participants from mainland China. Older adults had a higher level of fear compared with younger adults. Furthermore, having hypertension, liver disease, heart disease, cancer, anxiety, and insomnia were associated with a higher fear level. The descriptive analysis found that more than 40% of the study participants reported that the thought of COVID-19 scared them. About one-third of the study participants reported that when they thought about COVID-19, they felt nervous, uneasy, and depressed.

CONCLUSIONS

The psychometric properties of the adapted Fear Scale are acceptable to measure the fear of COVID-19 among Chinese people. Our study stresses the need for more psychosocial support and care to help this population cope with their fears during the pandemic.

International survey on fear and childbirth experience in pregnancy and the postpartum period during the COVID-19 pandemic: study protocol

INTRODUCTION

The COVID-19 pandemic has caused unprecedented disruptions around the world. Adding to the existing stress surrounding pregnancy and childbirth, the threat of infection and social isolation policies may negatively impact pregnant women and new mothers. Literature on the effect of COVID-19 on fear during pregnancy and childbirth experience is limited. As the COVID-19 pandemic continues to affect the global population, it is important to understand how it has impacted pregnant women and new mothers' experiences worldwide to inform perinatal care and interventions.

METHODS AND ANALYSIS

This multicountry study involving China and Canada targets to recruit 1000 pregnant women and new mothers who gave birth since 2020 in each participating country. Participants will be recruited online in the local language through mothers' groups, antenatal and postnatal clinics and hospital wards. All questionnaires will be completed online. Participants' level of fear, depression and childbirth experience will be assessed along with other sociodemographic, medical and COVID-related measures. Regression models will be used to compare the outcomes among the participating countries.

ETHICS AND DISSEMINATION

The study has been reviewed and approved by the institutional review boards of the participating countries. Findings will be disseminated in peer-reviewed journals and academic conferences. Results from this study may guide the formulation of future health guidelines and policies in the face of a pandemic.

A tail's tale: Biomechanical roles of dorsal thoracic spine of barnacle nauplii

Many marine invertebrates have complex life histories that begin with a planktonic larval stage. Similar to other plankton, these larval invertebrates often possess protruding body extensions, but their function beyond predator deterrence is not well-documented. For example, the planktonic nauplii of crustaceans have spines. Using the epibiotic pedunculate barnacle Octolasmis spp., we investigated how the dorsal thoracic spine affects swimming and fluid disturbance by comparing nauplii with their spines partially removed against those with intact spines. Our motion analysis showed that amputated Octolasmis spp. swam slower, in jerkier trajectories, and were less efficient per stroke cycle than those with intact spines. Amputees showed alterations in limb beat pattern: larger beat amplitude, increased phase lag, and reduced contralateral symmetry. These changes might partially help increase propulsive force generation and streamline the flow, but were insufficient to restore full function. Particle image velocimetry further showed that amputees had a larger relative area of influence, implying elevated risk by rheotactic predator. Body extensions and their interactions with limb motion play important biomechanical roles in shaping larval performance, which likely influences the evolution of form.

Exploring the role of simulation to foster interprofessional teamwork among medical and nursing students: A mixed-method pilot investigation in Hong Kong

Effective teamwork is a critical component of maintaining patient safety. However, there is lack of clarity on the best teaching approach to interprofessional teamwork training in medical and nursing curricula. This study aimed to compare the effects of blended classroom plus clinical simulation versus clinical simulation alone on teamwork attitudes, perceptions and performance in medical and nursing students in Hong Kong. This was a pilot study with a mixed-method research design, with both quantitative and qualitative evaluations. Students who studied medicine or nursing courses at a university in Hong Kong were invited to this study. They were assigned into two groups: clinical simulation alone versus blended classroom plus clinical simulation. The primary outcome was attitudinal change related to teamwork behaviours, which was measured using the Human Factors Attitude Survey. The secondary outcomes were perceptions of team-based learning and teamwork performance, which were accessed by the Team-Based Learning Student Assessment Instrument and Ottawa Global Rating Scale, respectively. Four focus group interviews were conducted after the training sessions. Conventional content analysis using inductive coding was performed with the qualitative data. Forty-six students participated in this study. There was a significant increase in the participants' positive attitudes on teamwork for both groups (intervention: MD = 5.36 and control: MD = 3.6, p <.05); however, there was no significant difference on increasing positive attitudes between the groups (estimate = 1.76, 95% CI [-8.59, 5.06], p = .61). Qualitative analysis identified four themes: (1) reconsidering professional roles in managing patients; (2) embodying the experience to share responsibility and complement each other's skills; (3) realizing the importance of trust and communication; and (4) engaging to achieve the mission within a limited time. This pilot study found that a blended classroom did not further improve teamwork attitudes, perceptions and performance in medical and nursing students compared with clinical simulation alone. Qualitative findings showed that students had reconsidered their professional roles in managing patients and realized the importance of teamwork in caring patients.

Evolution of Feeding Shapes Swimming Kinematics of Barnacle Naupliar Larvae: A Comparison between Trophic Modes

A central goal in evolutionary biology is connecting morphological features with ecological functions. For marine invertebrate larvae, appendage movement determines locomotion, feeding, and predator avoidance ability. Barnacle larvae are morphologically diverse, and the morphology of non-feeding lecithotrophic nauplii are distinct from those that are planktotrophic. Lecithotrophic larvae have a more globular body shape and simplified appendages when compared with planktotrophs. However, little is known about whether and how such morphological changes affect kinematics, hydrodynamics, and ecological functions. Here, we compared the nauplii kinematics and hydrodynamics of a lecithotrophic Rhizocephalan species, Polyascus planus, against that of the planktotrophic nauplii of an intertidal barnacle, Tetraclita japonica. High-speed, micro-particle image velocimetry analysis showed that the Polyascus nauplii swam faster and had higher amplitude and more synchronous appendage beating than the Tetraclita nauplii. This fast swimming was accompanied by a faster attenuation of induced flow with distance, suggesting reduced predation risk. Tetraclita nauplii had more efficient per beat cycles with less backward displacement during the recovery stroke. This "anchoring effect" resulted from the anti-phase beating of appendages. This movement, together with a high-drag body form, likely helps direct the suction flow toward the ventral food capturing area. In sum, the tradeoff between swimming speed and predation risks may have been an important factor in the evolution of the observed larval forms.

A Mobile App for Identifying Individuals With Undiagnosed Diabetes and Prediabetes and for Promoting Behavior Change: 2-Year Prospective Study

BACKGROUND

To decrease the burden of diabetes in society, early screening of undiagnosed diabetes and prediabetes is needed. Integrating a diabetes risk score into a mobile app would provide a useful platform to enable people to self-assess their risk of diabetes with ease.

OBJECTIVE

The objectives of this study were to (1) assess the profile of Diabetes Risk Score mobile app users, (2) determine the optimal cutoff value of the Finnish Diabetes Risk Score to identify undiagnosed diabetes and prediabetes in the Chinese population, (3) estimate users' chance of developing diabetes within 2 years of using the app, and (4) investigate high-risk app users' lifestyle behavior changes after ascertaining their risk level from the app.

METHODS

We conducted this 2-phase study among adults via mobile app and online survey from August 2014 to December 2016. Phase 1 adopted a cross-sectional design, with a descriptive analysis of the app users' profile. We used a Cohen kappa score to show the agreement between the risk level (as shown in the app) and glycated hemoglobin test results. We used sensitivity, specificity, and area under the curve to determine the optimal cutoff value of the diabetes risk score in this population. Phase 2 was a prospective cohort study. We used a logistic regression model to estimate the chance of developing diabetes after using the app. Paired t tests compared high-risk app users' lifestyle changes.

RESULTS

A total of 13,289 people used the app in phase 1a. After data cleaning, we considered 4549 of these as valid data. Most users were male, and 1811 (39.81%) had tertiary education or above. Among them, 188 (10.4%) users agreed to attend the health assessment in phase 1b. We recommend the optimal value of the diabetes risk score for identifying persons with undiagnosed diabetes and prediabetes to be 9, with an area under the receiver operating characteristic curve of 0.67 (95% CI 0.60-0.74), sensitivity of 0.70 (95% CI 0.58-0.80), and specificity of 0.57 (95% CI 0.47-0.66). At the 2-year follow-up, people in the high-risk group had a higher chance of developing diabetes (odds ratio 4.59, P=.048) than the low-risk group. The high-risk app users improved their daily intake of vegetables (baseline: mean 0.76, SD 0.43; follow-up: mean 0.93, SD 0.26; t₈₁=-3.77, P<.001) and daily exercise (baseline: mean 0.40, SD 0.49; follow-up: mean 0.54, SD 0.50; t₈₁=-2.08, P=.04).

CONCLUSIONS

The Diabetes Risk Score app has been shown to be a feasible and reliable tool to identify persons with undiagnosed diabetes and prediabetes and to predict diabetes incidence in 2 years. The app can also encourage high-risk people to modify dietary habits and reduce sedentary lifestyle.

Seroprevalence of Leptospirosis in Working Dogs

Working dogs are canine animals that have been trained to assist human beings in carrying out various tasks. They help in guarding property, performing rescues, assisting the visually impaired or physically handicapped, searching for drugs, explosives, and others. Leptospirosis is one of the most widespread zoonotic diseases in the world and a commonly occurring disease of the tropics and subtropics. In Malaysia, all working dogs are normally vaccinated with serovars, Pomona, Icterohaemorrhagiae, Canicola, and Grippotyphosa based on protocols recommended from other countries. The duration of immunity in vaccinated dogs for Leptospira can last up to 13 months; however, there is no full crossprotection between the different serovars. Five representative canine units from different government agencies in Malaysia (n = 96 dogs) were recruited in this study. For detection, the microscopic agglutination test was performed by incubating the serum from dogs with various serovars of leptospires, namely, Icterohaemorrhagiae, Canicola, Pomona, Grippotyphosa, Australis, Bataviae, Javanica, Tarassovi, Hebdomadis, Lai, and Pyrogenes. The plasma obtained was used for polymerase chain reaction (PCR) analysis, for the detection of 16S rRNA, and lipL 32 genes of Leptospira. Out of the 96 dogs sampled, only 3 dogs were positive toward serovars, Australis, Bataviae, and Javanica, based on the cutoff point at 1:80. The seroprevalence of canine leptospirosis in this population was 3.1% (n = 3/96). However, all 96 blood samples of working dogs tested negative for both pathogenic and nonpathogenic Leptospira genes. The results revealed that, by vaccination alone, working dogs were not fully protected against leptospirosis and could pose a risk to dog handlers. A preventative and control protocol for leptospirosis is warranted, and its implementation should be monitored and improved accordingly from time to time, in order to maintain a healthy condition in both working dogs and their handlers.

Automated otolith image classification with multiple views: an evaluation on Sciaenidae

Combined multiple 2D views (proximal, anterior and ventral aspects) of the sagittal otolith are proposed here as a method to capture shape information for fish classification. Classification performance of single view compared with combined 2D views show improved classification accuracy of the latter, for nine species of Sciaenidae. The effects of shape description methods (shape indices, Procrustes analysis and elliptical Fourier analysis) on classification performance were evaluated. Procrustes analysis and elliptical Fourier analysis perform better than shape indices when single view is considered, but all perform equally well with combined views. A generic content-based image retrieval (CBIR) system that ranks dissimilarity (Procrustes distance) of otolith images was built to search query images without the need for detailed information of side (left or right), aspect (proximal or distal) and direction (positive or negative) of the otolith. Methods for the development of this automated classification system are discussed.

Surface modification of uniaxial cyclic strain cell culture platform with temperature-responsive polymer for cell sheet detachment

Current cell sheet-based blood vessels lack biomimetic structure and require excessively long culture times that may compromise smooth muscle cell phenotype. We modified a commercially available product for uniaxial cell sheet conditioning with thermoresponsive copolymers. Thus, culture of detachable conditioned cell sheets is shortened while retaining structural integrity and contractility.

Successful lung transplant in a child with cystic fibrosis and persistent Blastobotrys rhaffinosifermentans infection

Fungal respiratory infections in patients with CF are a significant concern both pre- and post-lung transplantation (LTx). Fungal infection is associated with increased mortality post-LTx, and in the past decade, the prevalence of fungal colonization in Canadian pediatric patients with CF has increased. The emergence of novel fungal pathogens is particularly challenging to the transplant community, as little is known regarding their virulence and optimal management. We present a case of a successful double-lung transplant in a pediatric patient with CF who was infected pretransplantation with a novel yeast, Blastobotrys rhaffinosifermentans. This patient was treated successfully with aggressive antifungal therapy post-transplantation, followed by extended fungal prophylaxis. The significance of fungal colonization and infection in children with CF pre- and post-LTx is reviewed.

Preliminary inferences on the age-specific seriousness of human disease caused by avian influenza A(H7N9) infections in China, March to April 2013

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Preliminary inferences on the age-specific seriousness of human disease caused by avian influenza A(H7N9) infections in China, March to April 2013

Between 31 March and 21 April 2013, 102 laboratory-confirmed influenza A(H7N9) infections have been reported in six provinces of China. Using survey data on age-specific rates of exposure to live poultry in China, we estimated that risk of serious illness after infection is 5.1 times higher in persons 65 years and older versus younger ages. Our results suggest that many unidentified mild influenza A(H7N9) infections may have occurred, with a lower bound of 210–550 infections to date.

Mice lacking the alpha4 nicotinic receptor subunit fail to modulate dopaminergic neuronal arbors and possess impaired dopamine transporter function

Neuronal nicotinic acetylcholine receptors (nAChRs) at presynaptic sites can modulate dopaminergic synaptic transmission by regulating dopamine (DA) release and uptake. Dopaminergic transmission in nigrostriatal and mesolimbic pathways is vital for the coordination of movement and is associated with learning and behavioral reinforcement. We reported recently that the D2 DA receptor plays a central role in regulating the arbor size of substantia nigra dopaminergic neurons. Given the known effects of nAChRs on dopaminergic neurotransmission, we assessed the ability of the alpha4 nAChR subunit to regulate arbor size of dopaminergic neurons by comparing responses of wild-type and alpha4 nAChR subunit knockout [alpha4(-/-)] mice to long-term exposure to cocaine, amphetamine, nicotine, and haloperidol, and after substantia nigra neurotoxic lesioning. We found that dopaminergic neurons in adult drug-naive alpha4(-/-) mice had significantly larger terminal arbors, and despite normal short-term behavioral responses to drugs acting on pre- and postsynaptic D2 DA receptors, they were unable to modulate their terminal arbor in response to pharmacological manipulation or after lesioning. In addition, although synaptosome DA uptake studies showed that the interaction of the D2 DA receptor and the dopamine transporter (DAT) was preserved in alpha4(-/-) mice, DAT function was found to be impaired. These findings suggest that the alpha4 subunit of the nAChR is an independent regulator of terminal arbor size of nigrostriatal dopaminergic neurons and that reduced functionality of presynaptic DAT may contribute to this effect by impairing DA uptake.

Granulomatous infectious diseases associated with tumor necrosis factor antagonists

The relationship between the use of tumor necrosis factor antagonists and onset of granulomatous infection was examined using data collected through the Adverse Event Reporting System of the US Food and Drug Administration for January 1998-September 2002. Granulomatous infections were reported at rates of approximately 239 per 100,000 patients who received infliximab and approximately 74 per 100,000 patients who received etanercept (P<.001). Tuberculosis was the most frequently reported disease, occurring in approximately 144 and approximately 35 per 100,000 infliximab-treated and etanercept-treated patients, respectively (P<.001). Candidiasis, coccidioidomycosis, histoplasmosis, listeriosis, nocardiosis, and infections due to nontuberculous mycobacteria were reported with significantly greater frequency among infliximab-treated patients. Seventy-two percent of these infection occurred < or =90 days after starting infliximab treatment, and 28% occurred after starting etanercept treatment (P<.001). These data indicate a risk of granulomatous infection that was 3.25-fold greater among patients who received infliximab than among those who received etanercept. The clustering of reports shortly after initiation of treatment with infliximab is consistent with reactivation of latent infection.

Recombinant paramyosin (rec-Sj-97) tested for immunogenicity and vaccine efficacy against Schistosoma japonicum in mice and water buffaloes

A primary vaccine candidate antigen against schistosomiasis is paramyosin (pmy), a myofibrillar protein found exclusively in invertebrates. Here we report the results of vaccine trials against the Asian schistosome undertaken on inbred and outbred mice and water buffaloes using a bacterially expressed and purified form of Schistosoma japonicum pmy (rec-Sj-97). Vaccination of the mice resulted in high levels of specific anti-pmy IgG antibodies when compared with adjuvant controls and significant reduction in worm burdens and in liver eggs. Furthermore, a significant reduction in liver eggs was recorded in two of the three water buffalo vaccine trials undertaken and, in all three trials, high levels of specific anti-pmy IgG antibodies were generated. There was no evidence of any toxic effects and the vaccine preparations and Quil A adjuvant were clearly well tolerated. The development of a vaccine intended for livestock animals such as bovines would be beneficial in two ways; directly by blocking transmission of schistosomiasis to humans and economically by contributing to healthier livestock. We are encouraged by the consistent efficacy in the mouse and the buffalo vaccine trials that resulted in a significant decrease in liver eggs. Indeed, predictions from mathematical models indicate that an egg reduction effect of 42-45% in buffaloes would be sufficient when combined with human treatment to control schistosomiasis japonica in the marshes and lakes along the middle and upper reaches of the Yangtze River, the most highly endemic areas for the disease in China.

Impact of polymer tether length on multiple ligand-receptor bond formation

The promoters of cell adhesion are ligands, which are often attached to flexible tethers that bind to surface receptors on adjacent cells. Using a combination of Monte Carlo simulations, diffusion reaction theory, and direct experiments (surface force measurements) of the biotin-streptavidin system, we have quantified polymer chain dynamics and the kinetics and spatial range of tethered ligand-receptor binding. The results show that the efficiency of strong binding does not depend solely on the molecular architecture or binding energy of the receptor-ligand pair, nor on the equilibrium configuration of the polymer tether, but rather on its "rare" extended conformations.

Effector genes altered in MCF-7 human breast cancer cells after exposure to fractionated ionizing radiation

Understanding the molecular mechanisms involved in the response of tumors to fractionated exposures to ionizing radiation is important for improving radiotherapy and/or radiochemotherapy. In the present study, we examined the expression of stress-related genes in an MCF-7 cell population (MCF-IR20) that has been derived through treatment with fractionated irradiation (2 Gy per fraction with a total dose of 40 Gy). MCF-IR20 cells showed a 1.6-fold increase in sensitization with dose at 10% isosurvival in a clonogenic assay, and a reduced growth delay ( approximately 15 h compared to approximately 27 h), compared to the parental MCF-7 cells treated with a single dose of 5 Gy. To determine which effector genes were altered in the MCF-IR20 cells, the expression of stress-related effector genes was measured using a filter with 588 genes (Clontech) that included major elements involved in cell cycle control, DNA repair, and apoptosis. Compared to MCF-7 cells that were not exposed to fractionated radiation, 19 genes were up- regulated (2.2-5.1-fold) and 4 were down-regulated (2.7-3.4- fold) in the MCF-IR20 cells. In agreement with the array results, 6 up-regulated genes tested by RT-PCR showed elevated expression. Also, activities of the stress-related transcription factors NFKB, TP53 and AP1 showed a 1.2-4.5-fold increase after a single dose of 5 Gy in MCF-IR20 cells compared with parental MCF-7 cells. However, when the radioresistant MCF-IR20 cell were cultured for more than 12 passages after fractionated irradiation (MCF-RV), radioresistance was lost, with the radiosensitivity being the same as the parental MCF- 7 cells. Interestingly, expression levels of CCNB1, CD9 and CDKN1A in MCF-RV cells returned to levels expressed by the parental cells, whereas the expression levels of three other genes, MSH2, MSH6 and RPA remained elevated. To determine if any of the changes in gene expression could be responsible for the induced radioresistance, CCNB1 and CDKN1A, both of which were up-regulated in MCF-IR20 cells and down-regulated in MCF-RV cells, were studied further by transfection with antisense oligonucleotides. Antisense of CCNB1 significantly reduced the clonogenic survival of MCF- IR20 cells at doses of 5 and 10 Gy, from 42% to 26% and from 5.7% to 1.0%, respectively. Antisense of CDKN1A, however, had no effect on radiation survival of MCF-IR20 cells. In summary, these results suggest that stress-related effector genes are altered in cells after treatment with fractionated irradiation, and that up-regulation of CCNB1 is responsible, at least in part, for radioresistance after fractionated irradiation.

Tumor targeting of radiometal labeled anti-CEA recombinant T84.66 diabody and t84.66 minibody: comparison to radioiodinated fragments

Recombinant antibody fragments offer potential advantages over intact monoclonal antibodies in the radioimmunoscintigraphy (RIS) of solid tumors. Due to their smaller molecular size, antibody fragments have shown rapid tumor targeting and blood clearance, a more uniform tumor distribution and a lower potential to elicit a human immune response. Previously, we have expressed two genetically engineered antibody fragments, the T84.66 diabody (scFv dimer) and the T84.66 minibody (scFv-CH3 dimer), specific to carcinoembryonic antigen (CEA). When radioiodinated, both antibody fragments exhibited rapid tumor targeting and rapid blood clearance in xenografted mice. To extend and optimize their future clinical RIS utility with radiometals, these antibody fragments were conjugated with the macrocycle 1,4,7,10-tetraazacyclododecane N,N',N' ',N' "-tetraacetic acid (DOTA) and labeled with 111In. Tumor targeting and biodistribution studies were carried out in athymic mice xenografted with a human colorectal tumor cell line, LS174T. The [111In]T84.66 diabody (55 kDa) exhibited very rapid tumor targeting with 12.5 +/- 0.4% injected dose per gram (% ID g(-1) +/- standard error) at 2 h and reached a maximum of 13.3 +/- 0.9% ID g(-1) at 6 h. However, kidney uptake was observed to reached a peak of 183.5 +/- 21.0% ID g(-1) at 6 h, a result similar to that reported by others for other low molecular weight fragments labeled with radiometals. Preadministration of an oral dose of D-lysine resulted in a 59% lowering of the renal accumulation at 6 h, but was accompanied by a 31% reduction of tumor uptake to 9.2 +/- 1.2% ID g(-1). The second recombinant antibody fragment, the [111In]T84.66 minibody (80 kDa), displayed rapid tumor targeting of 14.2 +/- 6.1% ID g(-1) at 2 h, and reached a maximum activity of 24.5 +/- 6.1% ID g(-1) by 12 h. Renal uptake achieved a plateau of 12-13% ID g(-1) which cleared to 7.2% ID g(-1) at 72 h. However, hepatic uptake was elevated and reached a maximum of 26.0 +/- 1.0% ID g(-1) at 12 h in these xenograft-bearing mice. Experiments in nontumor bearing mice showed a reduction of hepatic activity at 12 h to 16.6 +/- 1.5% ID g(-1), indicative of an intrinsic hepatic accumulation of the [111In]DOTA-T84.66 minibody or metabolites. While the anti-CEA [111In]DOTA-T84.66 diabody and T84.66 minibody retain the rapid tumor targeting properties of the radioiodinated form, the normal organ accumulation (kidneys and liver, respectively) of the [111In]DOTA forms appeared problematic for RIS and RIT applications. Development of alternative blocking strategies or new metabolizable chelates are under investigation to enhance the utility of the radiometal form of these and other promising recombinant antibody fragments.

Numerical selection of optimal tumor imaging agents with application to engineered antibodies

Three analytic indicators were used to compare five members of a monoclonal antibody (Mab) family. The cognates consisted of the genetically engineered intact chimeric IgGI (cT84.66) and related engineered fragments [scFv, diabody, minibody, F(ab')2] reactive against the same epitope of carcinoembryonic antigen (CEA). All analyses were based on radioiodinated Mabs targeting to colorectal xenografts of LS174T tumors in nude mice. Affinity constants were evaluated initially. A second indicator was the imaging figure of merit (IFOM) which determines how rapidly a statistically significant tumor image can be acquired. Finally, deconvolution was used to determine tumor temporal response to an arterial bolus. This last analysis gave the possible tumor accumulation in the absence of normal tissue sequestration. Affinities were all in excess of 10(8) M-1 and were highest for the divalent Mabs. Using the IFOM criterion, an 131I label was best suited as a radiolabel for the intact (IgG) T84.66, while an 123I label indicated optimal imaging with either minibody or F(ab')2. Deconvolution analyses showed that divalent members behaved similarly while the univalent member (scFv) had a tumor residence time smaller by an order of magnitude. The diabody had the largest impulse response function, but renal uptake may limit its present usefulness.

Genes regulated in human breast cancer cells overexpressing manganese-containing superoxide dismutase

The mitochondrial antioxidant enzyme manganese-containing superoxide dismutase (MnSOD) functions as a tumor suppressor gene. Reconstitution of MnSOD expression in several human cancer cell lines leads to reversion of malignancy and induces a resistant phenotype to the cytotoxic effects of TNF and hyperthermia. The signaling pathways that underlie these phenotypic changes in MnSOD-overexpressing cells are unknown, although alterations in the activity of several redox-sensitive transcription factors, including AP-1 and NF-kappaB, have been observed. To determine the downstream signaling molecules involved in MnSOD-induced cell resistant phenotype, in the present study we analyzed the expression profile of several groups of genes related to stress response, DNA repair, and apoptosis, in a human breast cancer MCF-7 cell line overexpressing MnSOD (MCF+SOD). Of 588 genes examined, 5 (0.85%) were up-regulated (2-42-fold), and 11 (1.9%) were down-regulated (2-33-fold) in the MCF+SOD cells compared to the parental MCF-7 cells. The five up-regulated genes were MET, GADD153, CD9, alpha-catenin and plakoglobin. The genes with the most significant down-regulation included: vascular endothelial growth factor receptor 1, TNF-alpha converting enzyme, and interleukin-1beta. GADD153 (involved in the repair of DNA double strand breaks) showed a 33-fold increase in microarray analysis and these results were confirmed by RT-PCR. To further determine the specificity in MnSOD-induced gene regulation, MCF+SOD cells were stably transfected with an antisense MnSOD sequence whose expression was controlled by a tetracycline-inducible regulator. Expression of three up-regulated genes was measured after induction of antisense MnSOD expression. Interestingly, expression level of GADD153 but not MET or CD9 was reduced 24 h after antisense MnSOD induction. Together, these results suggest that reconstitution of MnSOD in tumor cells can specifically modulate the expression of down-stream effector genes. GADD153 and other elements observed in the MCF+SOD cells may play a key role in signaling the MnSOD-induced cell phenotypic change.

Proteolysis of human hemoglobin by schistosome cathepsin D

Schistosomes feed on human blood. They employ proteases to degrade hemoglobin from ingested erythrocytes, using the residues released for amino acid metabolism. However, the identity and the role of the participating protease(s) are unclear and controversial. Confocal microscopy localized schistosomal cathepsin D to the parasite gastrodermis, and revealed elevated protease expression in females. At sub-cellular level, cathepsin D was localized to superficial digestive vacuoles of the gut and to cisternae of the gastrodermal rough endoplasmic reticulum. Schistosome cathepsin D, expressed in insect cells, autoactivated at pH 3.6 to a approximately 40 kDa form that cleaved the substrates o-aminobenzoyl-Ile-Glu-Phe-nitroPhe-Arg-leu-NH(2) and hemoglobin. The NH(2)-terminal residues of mature cathepsin D of Schistosoma japonicum and Schistosoma mansoni were Asn1 and Gly1, respectively, revealing that the proregion peptide was comprised of 35 residues. The proteases cleaved hemoglobin at pH 2.5--4.6, releasing numerous fragments. S. Japonicum cathepsin D cleaved at 13 sites, S. mansoni cathepsin D at 15 sites. Early cleavage sites were alpha Phe33-Leu34 and beta Phe41-Phe42, while others included alpha Leu109-Ala-110 and beta Leu14-Trp15, demonstrating a preference for bulky hydrophobic residues at P1 and P1'. Most of the schistosomal cathepsin D cleavage sites were discrete from those of human cathepsin D. The gastrodermal location, elevated expression in females, acidic pH optima, similar substrate preferences in two species, and the discrete substrate preferences compared with human cathepsin D together provide compelling support for the hypothesis that schistosomal cathepsin D plays an integral role in hemoglobin proteolysis, and might be selectively targeted by drugs based on protease inhibition.

Differential diagnosis of malignant lymphomas and related disorders by specific pattern of expression of immunophenotypic markers revealed by multiparameter flow cytometry (Review)

The introduction of monoclonal antibodies (mAbs) for cell immunophenotyping and use of flow cytometry with the progressively improving software for multivariate analyses have revolutionized the diagnosis and influenced the classification of hematologic neoplasms. In this review we focus on the practical application of flow cytometry in the diagnosis and classification of malignant lymphomas and related lymphoproliferative disorders with special emphasis on differential diagnosis. A general approach to the utilization of flow cytometry (FC) in hematopathology with an algorithm to diagnose the most common neoplasms is presented. We discuss precursor B-cell neoplasms, mature B-cell neoplasms (SLL/CLL, mantle cell lymphoma, marginal zone lymphoma, hairy cell leukemia, diffuse large B-cell lymphoma, plasma cell dyscrasias and lymphomas with plasmacytic differentiation), precursor T-lymphoblastic leukemia and mature (peripheral) T-cell neoplasms, including T-SLL/PLL, anaplastic cell lymphomas and large granular cell leukemia/lymphoma. The text is accompanied by characteristic FC scatterplots of the discussed entities.

Reduced BDNF mRNA expression in the Parkinson's disease substantia nigra

Brain-derived neurotrophic factor (BDNF) has potent effects on survival and morphology of dopaminergic neurons and thus its loss could contribute to death of these cells in Parkinson's disease (PD). In situ hybridization revealed that BDNF mRNA is strongly expressed by dopaminergic neurons in control substantia nigra pars compacta (SNpc). In clinically and neuropathologically typical PD, SNpc BDNF mRNA expression is reduced by 70% (P = 0.001). This reduction is due, in part, to loss of dopaminergic neurons which express BDNF. However, surviving dopaminergic neurons in the PD SNpc also expressed less BDNF mRNA (20%, P = 0.02) than their normal counterparts. Moreover, while 15% of control neurons had BDNF mRNA expression >1 SD below the control mean, twice as many (28%) of the surviving PD SNpc dopaminergic neurons had BDNF mRNA expression below this value. This 13% difference in proportions (95% CI 8-17%, P < or = 0.000001) indicates the presence of a subset of neurons in PD with particularly low BDNF mRNA expression. Moreover, both control and PD neurons displayed a direct relationship between the density of BDNF mRNA expression per square micrometer of cell surface and neuronal size (r(2) = 0.93, P </= 0.00001) which was lost only in PD neurons expressing the lowest levels of BDNF mRNA. If BDNF is an autocrine/paracrine factor for SNpc dopaminergic neurons, loss of BDNF-expressing neurons may compromise the well-being of their surviving neighbors. Moreover, neurons expressing particularly low levels of BDNF mRNA may be those at greatest risk of injury in PD and possibly the trigger for the degeneration itself.

Phenotypic characterization of an alpha 4 neuronal nicotinic acetylcholine receptor subunit knock-out mouse

Neuronal nicotinic acetylcholine receptors (nAChR) are present in high abundance in the nervous system (Decker et al., 1995). There are a large number of subunits expressed in the brain that combine to form multimeric functional receptors. We have generated an alpha(4) nAChR subunit knock-out line and focus on defining the behavioral role of this receptor subunit. Homozygous mutant mice (Mt) are normal in size, fertility, and home-cage behavior. Spontaneous unconditioned motor behavior revealed an ethogram characterized by significant increases in several topographies of exploratory behavior in Mt relative to wild-type mice (Wt) over the course of habituation to a novel environment. Furthermore, the behavior of Mt in the elevated plus-maze assay was consistent with increased basal levels of anxiety. In response to nicotine, Wt exhibited early reductions in a number of behavioral topographies, under both unhabituated and habituated conditions; conversely, heightened levels of behavioral topographies in Mt were reduced by nicotine in the late phase of the unhabituated condition. Ligand autoradiography confirmed the lack of high-affinity binding to radiolabeled nicotine, cytisine, and epibatidine in the thalamus, cortex, and caudate putamen, although binding to a number of discrete nuclei remained. The study confirms the pivotal role played by the alpha(4) nAChR subunit in the modulation of a number of constituents of the normal mouse ethogram and in anxiety as assessed using the plus-maze. Furthermore, the response of Mt to nicotine administration suggests that persistent nicotine binding sites in the habenulo-interpeduncular system are sufficient to modulate motor activity in actively exploring mice.

Pharmacogenetics: role in modifying drug dosage regimens

With the advent of new molecular biology and scientific techniques, there is better understanding of genetic polymorphisms in oxidative drug metabolism systems today. These systems are important in pharmacogenetic studies which genotype polymorphic alleles encoding drug metabolising enzymes to enable the individual's drug metabolising phenotype to be found. Once found, the knowledge can be used to tailor drug dosage regimens to an individual to maximise therapeutic efficacy and minimise adverse drug reactions (ADRs). The knowledge could also be used to optimise drug development programmes so that all the subgroups within a target population are adequately represented in clinical trails.

X-ray and neutron surface scattering for studying lipid/polymer assemblies at the air-liquid and solid-liquid interfaces

Simple mono- and bilayers, built of amphiphilic molecules and prepared at air-liquid or solid-liquid interfaces, can be used as models to study such effects as water penetration, hydrocarbon chain packing, and structural changes due to head group modification. In the paper, we will discuss neutron and X-ray reflectometry and grazing incidence X-ray diffraction techniques used to explore structures of such ultra-thin organic films in different environments. We will illustrate the use of these methods to characterize the morphologies of the following systems: (i) polyethylene glycol-modified distearoylphosphatidylethanolamine monolayers at air-liquid and solid-liquid interfaces; and (ii) assemblies of branched polyethyleneimine polymer and dimyristoylphophatidylcholine lipid at solid-liquid interfaces.

High-resolution microPET imaging of carcinoembryonic antigen-positive xenografts by using a copper-64-labeled engineered antibody fragment

Rapid imaging by antitumor antibodies has been limited by the prolonged targeting kinetics and clearance of labeled whole antibodies. Genetically engineered fragments with rapid access and high retention in tumor tissue combined with rapid blood clearance are suitable for labeling with short-lived radionuclides, including positron-emitting isotopes for positron-emission tomography (PET). An engineered fragment was developed from the high-affinity anticarcinoembryonic antigen (CEA) monoclonal antibody T84.66. This single-chain variable fragment (Fv)-C(H)3, or minibody, was produced as a bivalent 80 kDa dimer. The macrocyclic chelating agent 1,4,7, 10-tetraazacyclododecane-N,N',N", N"'-tetraacetic acid (DOTA) was conjugated to the anti-CEA minibody for labeling with copper-64, a positron-emitting radionuclide (t(1/2) = 12.7 h). In vivo distribution was evaluated in athymic mice bearing paired LS174T human colon carcinoma (CEA positive) and C6 rat glioma (CEA negative) xenografts. Five hours after injection with (64)Cu-DOTA-minibody, microPET imaging showed high uptake in CEA-positive tumor (17.9% injected dose per gram +/- 3.79) compared with control tumor (6.0% injected dose per gram +/- 1.0). In addition, significant uptake was seen in liver, with low uptake in other tissues. Average target/background ratios relative to neighboring tissue were 3-4:1. Engineered antibody fragments labeled with positron-emitting isotopes such as copper-64 provide a new class of agents for PET imaging of tumors.

Truncation of blood curves to enhance imaging and therapy with monoclonal antibodies

Targeting of monoclonal antibody (Mab) to solid tumor sites is a function of the blood curve of activity versus time. It has been suggested that the blood curve be artificially reduced to approach zero so that the contrast between tumor and blood uptake is maximized. We analyzed tumor uptake as a function of the time tc of blood curve truncation. By using a convolution approach, we were able to find the optimal times for setting the blood curve to zero in either diagnostic or therapeutic animal examples. Two iodinated cT84.66 anti-CEA engineered fragments, diabody and minibody, were considered using previous data from nude mouse studies involving the LS174T colorectal tumor model. Figures of merit (FOMs) were used to compare ordinary and truncated blood curves and their associated tumor accumulations. Using a 1231 label, it was seen that the appropriate time for diagnostic truncation occurred when tumor uptake, as measured, was a maximum. The corresponding point for therapy (with 1311 as a label) was at infinite time. We also demonstrated that the use of traditional indices led to ambiguities in the choice of truncation times. The traditional therapy index, the ratio of the integral of the tumor uptake to the integral of the blood uptake, was found to be a numerical constant independent of tc. This ratio was proved to be the integral of the tumor impulse response function. Use of such convolution techniques to assess truncation of the perfused material is probably also applicable to multistep processes as well as to lesion targeting with other tumor-specific pharmaceuticals.

Pharmacogenetics: the molecular genetics of CYP2D6 dependent drug metabolism

INTRODUCTION

Genetic variation of drug metabolising enzymes has been recognised as one of the major causes of the inter-individual variability to drug response. The vast majority of drugs are degraded via a small number of metabolic pathways, mainly by microsomal P-450 enzymes localised in the liver and, to a minor extent, in the small intestine. Of these, CYP3A4 is the isozyme involved in the metabolism of most of the clinically useful drugs (50%). This is followed by CYP2D6 (20%), CYP2C9 and CYP2C19 (15%). In addition, minor pathways are catalysed by CYP2E1, CYP1A2, CYP2A6 and unidentified P-450s. Almost 40% of human P-450 dependent drug metabolism is carried out by genetically polymorphic enzymes. Polymorphisms generated by mutations in the genes for these enzymes cause quantitatively or qualitatively altered enzyme expression or activity through multiple molecular mechanisms. While CYP3A4 genetic polymorphisms are just beginning to be unraveled, extensive studies on the CYP2D6 gene over the last decade have identified at least 53 alleles. Of these, more than 20 of them are known to significantly alter the metabolism of CYP2D6 substrates.

METHODS

This article reviews the information derived from various studies over the past decade and explains the molecular basis of functional differences in CYP2D6 variants, especially with respect to inter-ethnic differences and their clinical implications.

RESULTS

CYP2D6 activity ranges from complete absence to ultra-rapid metabolism. Large inter-individual and inter-ethnic variability exists in the activity of the enzyme, and consequently in the disposition of drugs undergoing oxidative metabolism.

CONCLUSIONS

Pharmacokinetic differences resulting from these polymorphisms show potentially important clinical consequences.

Early direct and transneuronal effects in mice with targeted expression of a toxin gene to D1 dopamine receptor neurons

The neurochemical profile was examined at postnatal day 3-4 in mutant mice generated by in vivo Cre mediated activation of an attenuated diphtheria toxin gene inserted into the D1 dopamine receptor gene locus. An earlier study of this model had shown that D1 dopamine receptor, substance P and dynorphin were not expressed in the striatum. Quantitative in situ hybridization analysis showed an increase in D2 dopamine receptor and enkephalin messenger RNA expression. The nigrostriatal pathway in the mutant pups was intact with a normal number of dopaminergic neurons in the substantia nigra and the ventral tegmental area in addition to a normal pattern of striatal dopamine transporter and tyrosine hydroxylase immunoreactivity. Quantitative analysis of striatal dopamine transporter density using [3H]mazindol showed a reduction of 26% suggesting a degree of transneuronal down-regulation. There was also a 49% reduction of striatal GABA receptor binding and a 36% reduction of striatal muscarinic receptor binding in mutant pups. The number of healthy striatal neuropeptide Y-containing interneurons was also substantially down-regulated in the mutant striatum. In contrast, there was an increase in the number of striatal cholinergic interneurons. Down-regulated cortical GABA receptor and muscarinic receptor binding was also observed in addition to subtle morphological changes in the neuropeptide Y-expressing population of cortical neurons. The changes reflect the early cascade of events which follows the ablation of D1 dopamine receptor-positive cells. Although extensive changes in a number of striatal and cortical neurons were demonstrated, only subtle transneuronal effects were seen in the nigrostriatal pathway.

Late direct and transneuronal effects in mice with targeted expression of a toxin gene to D1 dopamine receptor neurons

Detailed analysis of a novel transgenic model of basal ganglia disease has been undertaken. In this model the expression of an attenuated form of the diphtheria toxin gene was tightly controlled by D1 dopamine receptor regulatory domains. The behavioral and both direct toxin-mediated and transneuronal effects observed in pups in the first postnatal week have been described. Although younger pups are bradykinetic, older pups have a hyperkinetic syndrome with gait abnormality, postural instability and myoclonic jerks typical of human basal ganglia diseases such as Huntington's disease. As expected, striatal D1 dopamine receptor, dynorphin and substance P transcripts were not detected by in situ hybridization but there was a 27% increase in striatal D2 dopamine receptor messenger RNA and a 65% increase in enkephalin messenger RNA expression. Receptor autoradiographic studies confirmed the lack of D1-class binding in the mutant striatum and in contrast to young pups, a substantial increase in striatal D2-class binding. Autoradiographic quantitation also showed a 30% increase in striatal dopamine transporter binding. In addition to the changes described in the striatopallidal and nigrostriatal pathways, up-regulated dynorphin and substance P messenger RNA expression was also seen in the cortex. The capacity of the developing brain for neurochemical adaptation following injury is dramatic. The results show that primary loss of D1 dopamine receptor-positive striatonigral pathway neurons is sufficient to generate a hyperkinetic phenotype.

Analysis of false-negative diagnoses on endoscopic brush cytology of biliary and pancreatic duct strictures: the experience at 2 university hospitals

CONTEXT

Endoscopic brush cytology is a valuable technique for the diagnosis of pancreatobiliary malignancy. Despite its widespread use, the sensitivity of this method has been reported as approximately 50%. The specificity is usually higher than 95%. Few reports have systematically analyzed the reasons for this relatively low sensitivity.

OBJECTIVES

To determine the rate and reasons for false-negative diagnoses in endoscopic brushing cytology of biliary and pancreatic ducts based on the results of sensitivity, specificity, accuracy, and positive and negative predictive values.

DESIGN

Retrospective analysis of laboratory data and slide review of false-negative cases.

SETTING

Two tertiary care state university hospitals.

PATIENTS

A total of 183 pancreatobiliary brushing specimens obtained from patients undergoing endoscopic retrograde cholangiopancreatography for biliary or pancreatic duct disease for a 4- to 5-year period.

INTERVENTION

Endoscopic retrograde cholangiopancreatography brushings.

MAIN OUTCOME MEASURES

Determination of sensitivity, specificity, accuracy, and positive and negative predictive values. Analysis of false-negative results.

RESULTS

The sensitivity, specificity, accuracy, and positive and negative predictive values, overall, were 48%, 98%, 79%, 92%, and 76%, respectively. Sampling error was a major cause of false-negative diagnoses (67%), followed by interpretive (17%) and technical errors (17%).

CONCLUSIONS

Improvements in sensitivity and diagnostic accuracy for cancer of the pancreatobiliary tract can be achieved by optimizing slide preparatory techniques. Also, enhancement of the cytologist's diagnostic skills enables the identification of the morphologic features of premalignant lesions. Repeat brushings are indicated for suspicious or negative results not consistent with the clinical or radiologic findings.

No objective benefit from steroids inhaled via a spacer in infants recovering from bronchiolitis

A double-blind randomized placebo-controlled trial was conducted to investigate the efficacy of 3 months' inhaled steroids delivered via a spacer device with face mask attachment to infants recovering from bronchiolitis. Forty-eight previously healthy infants recovering from their first documented episode of acute bronchiolitis were randomized to receive 150 microg fluticasone propionate (FP) b.i.d. or placebo delivered via the Babyhaler spacer. Longitudinal assessments were performed on seven occasions over 1 yr based on symptom diaries and health records, clinical examinations, overnight cough recordings and oxygen saturation readings. Lung function was measured 6 months after hospital discharge. Forty-three infants completed the trial (FP 21, placebo 22). There were no significant differences in the three objective end-points measured, recorded night cough, oxygen saturation and lung function test results. Symptom scores were low in both the FP and placebo groups with the absence of (0) or mild (1) symptoms > or =90% of the trial days. No statistical differences in symptom frequency, use of rescue respiratory medications or hospital admissions between treatment groups were found throughout the trial or follow-up periods. In conclusion, the use of inhaled fluticasone propionate in infants recovering from acute bronchiolitis cannot be recommended.

Evaluating changes in stable chromosomal translocation frequency in patients receiving radioimmunotherapy

PURPOSE

The lack of any consistent correlation between radioimmunotherapy (RIT) dose and observed hematologic toxicity has made it difficult to validate RIT radiation dose estimates to marrow. Stable chromosomal translocations (SCT) which result after radiation exposure may be a biologic parameter that more closely correlates with RIT radiation dose. Increases in the frequency of SCT are observed after radiation exposure and are highly correlated with absorbed radiation dose. SCT are cumulative after multiple radiation doses and conserved through an extended number of cell divisions. The purpose of this study was to evaluate whether increases in SCT frequency were detectable in peripheral lymphocytes after RIT and whether the magnitude of these increases correlated with estimated radiation dose to marrow and whole body.

METHODS AND MATERIALS

Patients entered in a Phase I dose escalation therapy trial each received 1-3 intravenous cycles of the radiolabeled anti- carcinoembryonic antigen (CEA) monoclonal antibody, 90Y-chimeric T84.66. Five mCi of 111In-chimeric T84.66 was co-administered for imaging and biodistribution purposes. Blood samples were collected immediately prior to the start of therapy and 5-6 weeks after each therapy cycle. Peripheral lymphocytes were harvested after 72 hours of phytohemagglutinin stimulation and metaphase spreads prepared. Spreads were then stained by fluorescence in situ hybridization (FISH) using commercially available chromosome paint probes to chromosomes 3 and 4. Approximately 1000 spreads were evaluated for each chromosome sample. Red marrow radiation doses were estimated using the AAPM algorithm and blood clearance curves.

RESULTS

Eighteen patients were studied, each receiving at least one cycle of therapy ranging from 5-22 mCi/m2. Three patients received 2 cycles and two patients received 3 cycles of therapy. Cumulative estimated marrow doses ranged from 9.2 to 310 cGy. Increases in SCT frequencies were observed after each cycle for both chromosomes 3 and 4 in 16 of 18 patients and in at least one chromosome for the remaining 2 patients. Cumulative increases in SCT frequencies ranged from 0.001 to 0.046 with no major differences observed between chromosomes 3 and 4. A linear correlation between cumulative marrow dose and increases in SCT frequencies was observed for chromosome 3 (R2 = 0.63) and chromosome 4 (R2 = 0.80). A linear correlation was also observed between increases in SCT frequency and whole body radiation dose or administered activity (R2 = 0.67-0.89). There was less correlation between observed decrease in wbc or platelet counts and marrow dose, whole body dose, or administered activity (R2 = 0.28-0.43).

CONCLUSIONS

Increases in SCT frequency were detectable in peripheral lymphocytes after low dose-rate RIT irradiation. A linear correlation was observed between increases in SCT and marrow dose, whole body dose, and administered activity. This correlation provides one of the strongest radiation dose-response and activity-response relationships observed with RIT. The detection of SCT may therefore have application as an in situ integrating biodosimeter after RIT. This biologic parameter should prove useful in comparing effects on marrow for different therapeutic radionuclides and in comparing effects of RIT and external beam radiation doses on a cGy per cGy basis. As a result, this should allow for a more direct comparison between different methods of irradiation and in further refinement of radioimmunotherapy dose estimates and dosimetry methodology.

Initial clinical experience evaluating Yttrium-90-chimeric T84.66 anticarcinoembryonic antigen antibody and autologous hematopoietic stem cell support in patients with carcinoembryonic antigen-producing metastatic breast cancer

cT84.66 is a human/murine IgG1 with high affinity and specificity for carcinoembryonic antigen (CEA). An earlier Phase I trial defined the maximum tolerated dose for 90Y-diethylenetriaminepentaacetic acid (DTPA)-cT84.66 at 22 mCi/m2. Dose-limiting toxicities were reversible leukopenia and thrombocytopenia. The purpose of this Phase I trial was to evaluate the feasibility and toxicities of administering higher activities of 90Y-DTPA-cT84.66 with stem cell support in patients with CEA-producing breast cancer. Patients with CEA-producing breast cancer refractory to standard therapies underwent peripheral stem cell collection followed by infusion of 111indium-DTPA-cT84.66. Those patients demonstrating tumor targeting received a single therapy dose of 90Y-DTPA-cT84.66, followed by Ca-DTPA infusion for 72 h posttherapy. Stem cells were reinfused following a divided schedule. To date, seven patients have been accrued to this trial. Each patient received an imaging dose of (111)In-cT84.66. Six patients demonstrated tumor imaging and received a single cycle of 90Y-cT84.66 at 15 mCi/m2 (three patients) and 22.5 mCi/m2 (three patients). One patient did not demonstrate tumor imaging and was not treated. At these administered activities, 90Y-cT84.66 was well tolerated. No dose-limiting toxicities have been observed. All patients demonstrated hematopoietic recovery after stem cell infusion. One patient demonstrated stable disease for 4 months; one patient had stable disease and reduction of bone pain for 3 months; and a third patient experienced >50% reduction of an ovarian metastasis, resolution of malignant pleural effusion, stable pleural metastases, and stable bone scan for 14 months. Preliminary results from this ongoing Phase I trial are promising and demonstrate the feasibility and potential for antitumor effects of stem cell supported 90Y-cT84.66 therapy in patients with CEA-producing breast cancers.

A method for patient-specific absorbed dose estimation for internal beta emitters

The purpose of the study was to determine a technique for estimating patient-specific absorbed radiation doses in radioimmunotherapy and other internal emitter therapies. Beta Radiation sources were considered, with 90Y being the radionuclide of primary interest. Organ uptake of activity was determined using a merged set of computed tomography and planar nuclear images. Estimation of local absorbed dose was accomplished using a voxel source kernel. Voxel size was 0.2 x 0.2 x 0.5 cm; dimensions were from the digital resolution of the nuclear and computed tomography data sets. Dose-volume histograms were also obtained due to the voxel nature of the estimations. Organ dose estimates were made for two patients receiving the chimeric anticarcinoembryonic antigen antibody cT84.66. Considerable variation was observed when comparing the voxel kernel results with medical internal radiation dosimetry values obtained via the MIRDOSE3 program. Primary uncertainty in the organ dose estimates was determined to be due to the variation in organ mass. By correcting the S values in that program by the organ mass ratio, we found generally good agreement between our method and MIRDOSE3. We conclude that patient-specific absorbed doses can be estimated for 90Y-labeled antibodies.

Sprouting of dopaminergic axons after striatal injury: confirmation by markers not dependent on dopamine metabolism

Striatal injury increases dopamine metabolism in the nigrostriatal system but it is unclear whether this response is due to increased synthesis and activation of tyrosine hydroxylase within existing dopamine terminals and/or branching and sprouting of new terminals. While monitoring the density of tyrosine hydroxylase immunoreactive fibers suggests that sprouting occurs, this technique alone cannot adequately answer this question since the intensity of staining and thus the visibility of individual fibers are intimately linked to dopaminergic activity. However, by examining axons and their branches using markers that are independent of dopamine metabolism it is possible to determine whether dopaminergic sprouting does in fact take place. One month after using a Scouten wire knife to create a small lesion in the left striatum of normal C57/bl-6 mice, silver staining revealed an increase in the total number of neuronal fibers throughout the injured striatum. This was accompanied by intense staining of tyrosine hydroxylase-positive fibers around the wound and an increased density of striatal fibers labeled with dextran-biotin after injection of this neuronal tracer into the substantia nigra 1 month after striatal surgery and 5 days prior to sacrifice. The increase in tyrosine hydroxylase immunoreactivity confirms previous observations of increased dopaminergic activity after striatal injury. The increases in silver staining and dextran-biotin transport provide independent evidence that this increase in dopaminergic activity occurs because of sprouting of new fibers originating in the substantia nigra.

Rates of abnormalities and infectious agents in cervical smears from female inmates in Texas: comparison with private and university clinic patients

Inmates are generally considered a high-risk population for gynecologic neoplasia and sexually transmitted diseases. Cervical smears from prisoners of the Texas Department of Corrections (TDC) were expected initially to have higher rates of cellular abnormalities and infectious agents than do smears from the general population. The cytologic findings from 25,522 TDC gynecologic smears were compared with those of 6883 cases from The University of Texas Medical Branch (UTMB) affiliated physician private clinics, and with 56,178 from the UTMB hospital clinics. The period of study was from September 1995 to February 1998. This study revealed a 5.23% higher rate of abnormalities for TDC gynecologic smears as compared with that for the private clinic smears. However, the TDC rate of abnormalities was unexpectedly 1.08% lower than that for the UTMB clinic smears. These unexpected findings were probably the result of a more selected high-risk population referred to the UTMB clinics. The TDC smears showed also the highest incidence of trichomoniasis.

Polymer-cushioned bilayers. I. A structural study of various preparation methods using neutron reflectometry

This neutron reflectometry study evaluates the structures resulting from different methods of preparing polymer-cushioned lipid bilayers. Four different techniques to deposit a dimyristoylphosphatidylcholine (DMPC) bilayer onto a polyethylenimine (PEI)-coated quartz substrate were examined: 1) vesicle adsorption onto a previously dried polymer layer; 2) vesicle adsorption onto a bare substrate, followed by polymer adsorption; and 3, 4) Langmuir-Blodgett vertical deposition of a lipid monolayer spread over a polymer-containing subphase to form a polymer-supported lipid monolayer, followed by formation of the outer lipid monolayer by either 3) horizontal deposition of the lipid monolayer or 4) vesicle adsorption. We show that the initial conditions of the polymer layer are a critical factor for the successful formation of our desired structure, i.e., a continuous bilayer atop a hydrated PEI layer. Our desired structure was found for all methods investigated except the horizontal deposition. The interaction forces between these polymer-supported bilayers are investigated in a separate paper (Wong, J. Y., C. K. Park, M. Seitz, and J. Israelachvili. 1999. Biophys. J. 77:1458-1468), which indicate that the presence of the polymer cushion significantly alters the interaction potential. These polymer-supported bilayers could serve as model systems for the study of transmembrane proteins under conditions more closely mimicking real cellular membrane environments.

Polymer-cushioned bilayers. II. An investigation of interaction forces and fusion using the surface forces apparatus

We have created phospholipid bilayers supported on soft polymer "cushions" which act as deformable substrates (see accompanying paper, Wong, J. Y., J. Majewski, M. Seitz, C. K. Park, J. N. Israelachvili, and G. S. Smith. 1999. Biophys. J. 77:1445-1457). In contrast to "solid-supported" membranes, such "soft-supported" membranes can exhibit more natural (higher) fluidity. Our bilayer system was constructed by adsorption of small unilamellar dimyristoylphosphatidylcholine (DMPC) vesicles onto polyethylenimine (PEI)-supported Langmuir-Blodgett lipid monolayers on mica. We used the surface forces apparatus (SFA) to investigate the long-range forces, adhesion, and fusion of two DMPC bilayers both above and below their main transition temperature (T(m) approximately 24 degrees C). Above T(m), hemi-fusion activation pressures of apposing bilayers were considerably smaller than for solid-supported bilayers, e.g., directly supported on mica. After separation, the bilayers naturally re-formed after short healing times. Also, for the first time, complete fusion of two fluid (liquid crystalline) phospholipid bilayers was observed in the SFA. Below T(m) (gel state), very high pressures were needed for hemi-fusion and the healing process became very slow. The presence of the polymer cushion significantly alters the interaction potential, e.g., long-range forces as well as fusion pressures, when compared to solid-supported systems. These fluid model membranes should allow the future study of integral membrane proteins under more physiological conditions.

Acupuncture in the management of pain of musculoskeletal and neurologic origin

Acupuncture has been used as therapeutic treatment for the health of the Chinese people for more than 3000 years; it is a system for diagnosing and treating disease using fine needles inserted into specific points of the body. Acupuncture can treat a wide variety of conditions. This article discusses the use of acupuncture in the management of pain of musculoskeletal and neurologic origin, with a focus on pain in spinal cord injuries.

Effect of chronic angiotensin-converting enzyme inhibition on striatal dopamine content in the MPTP-treated mouse

We have previously shown that chronic treatment with the angiotensin-converting enzyme inhibitor perindopril increased striatal dopamine levels by 2.5-fold in normal Sprague-Dawley rats, possibly via modulation of the striatal opioid or tachykinin levels. In the present study, we investigated if this effect of perindopril persists in an animal model of Parkinson's disease, the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mouse. C57BL/6 mice were treated with the neurotoxin (30 mg/kg/day intraperitoneally) for 4 days and then left for 3 weeks to allow the degeneration of striatal dopaminergic terminals. At this time, the mice exhibited a 40% decrease in striatal dopamine content and an accompanying 46% increase in dopamine D2 receptor levels compared with control untreated mice. The dopamine content returned to control levels, and the increase in dopamine D2 receptor levels was attenuated in mice treated with perindopril (5 mg/kg/day orally for 7 days) 2 weeks after the last dose of MPTP. When the angiotensin-converting enzyme inhibitor was administered (5 mg/kg/day for 7 days) immediately after the cessation of the MPTP treatment, there was no reversal of the effect of the neurotoxin in decreasing striatal dopamine content. Our results demonstrate that perindopril is an effective agent in increasing striatal dopamine content in an animal model of Parkinson's disease.

A radionuclide therapy treatment planning and dose estimation system

An object-oriented software system is described for estimating internal emitter absorbed doses using a set of computer modules operating within a personal computer environment. The system is called the Radionuclide Treatment Planning and Absorbed Dose Estimation System (RTDS). It is intended for radioimmunotherapy applications, although other forms of internal emitter therapy may also be considered.

METHODS

Four software modules interact through a database backend. Clinical, demographic and image data are directly entered into the database. Modules include those devoted to clinical imaging (nuclear, CT and MR), activity determination, organ compartmental modeling and absorbed dose estimation.

RESULTS

Both standard phantom (Medical Internal Radiation Dose [MIRD]) and patient-specific absorbed doses are estimated. All modules interact with the database backend so that changes in one process do not influence other operations. Results of the modular operations are written to the database as computations are completed. Dose-volume histograms are an intrinsic part of the output for patient-specific absorbed dose estimates. A sample dose estimate for a potential 90Y monoclonal antibody is described.

CONCLUSION

A four-module software system has been implemented to estimate MIRD phantom and patient-specific absorbed doses. Computations of the doses and their statistical distribution for a pure beta emitter such as 90Y take approximately 1 min on a 300 MHz personal computer.

Intrapatient consistency of imaging biodistributions and their application to predicting therapeutic doses in a phase I clinical study of 90Y-based radioimmunotherapy

Intrapatient variation in the biodistribution of the chimeric monoclonal antibody cT84.66 was assessed in 19 patients having a variety of carcinoembryonic antigen (CEA) positive tumors. The two studies, including whole-body imaging and blood and urine specimen collections, were conducted within 14 days of each other using (111)In-cT84.66 at a fixed total protein dose of 5 mg per patient per study. An initial pretherapy infusion of (111)In-cT84.66 was administered followed by a therapy coinfusion of (111)In-ct84.66 and 90Y-cT84.66 A closed five-compartment model was used to integrate source organ activity curves as residence time inputs into the MIRDOSE3 program. Normal organ absorbed doses were estimated for 90Y-cT84.66, the corresponding radiotherapeutic agent. For the two (111)In-cT84.66 biodistributions, all data were modeled with a R2 value of between 0.72 and 1.00 with the exception of the urine data taken during therapy. This was due to the need of diethylenetriaminepentaacetic acid during the therapy phase because of the possibility that yttrium might escape from the chelator attached to the antibody. With the assurance that the biodistributions were reproducible, we were able to estimate the 90Y-cT84.66 absorbed doses on a per-patient basis. Concordance coefficients showing the agreement between the imaging and therapy phase dose estimates were between the 0.60 and 0.99 levels for liver, spleen, red marrow, total body, and other organ systems. Median results were: 27, 17, and 2.7 rad/mCi of 90Y-cT84.66 for liver, spleen, and red marrow, respectively. Because of decreases in platelets and white cells as the amount of 90Y was increased, dose-limiting toxicity was found at 22 mCi/m2. We conclude that patient biodistributions were consistent over time to 14 days so as to allow absorbed dose estimation in a radioimmunotherapy trial involving the cT84.66 anti-CEA antibody.

Activated macrophages and microglia induce dopaminergic sprouting in the injured striatum and express brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor

Nigrostriatal dopaminergic neurons undergo sprouting around the margins of a striatal wound. The mechanism of this periwound sprouting has been unclear. In this study, we have examined the role played by the macrophage and microglial response that follows striatal injury. Macrophages and activated microglia quickly accumulate after injury and reach their greatest numbers in the first week. Subsequently, the number of both cell types declines rapidly in the first month and thereafter more slowly. Macrophage numbers eventually cease to decline, and a sizable group of these cells remains at the wound site and forms a long-term, highly activated resident population. This population of macrophages expresses increasing amounts of glial cell line-derived neurotrophic factor mRNA with time. Brain-derived neurotrophic factor mRNA is also expressed in and around the wound site. Production of this factor is by both activated microglia and, to a lesser extent, macrophages. The production of these potent dopaminergic neurotrophic factors occurs in a similar spatial distribution to sprouting dopaminergic fibers. Moreover, dopamine transporter-positive dopaminergic neurites can be seen growing toward and embracing hemosiderin-filled wound macrophages. The dopaminergic sprouting that accompanies striatal injury thus appears to result from neurotrophic factor secretion by activated macrophages and microglia at the wound site.

Resection with external beam and intraoperative radiotherapy for recurrent colon cancer

OBJECTIVE

To review treatment outcomes for patients with locoregional recurrent colon cancer who underwent resection, intraoperative radiotherapy (IORT), and external beam radiotherapy (EBRT).

DESIGN

Retrospective study of patients treated between January 1990 and June 1994.

SETTING

Tertiary care cancer center.

PATIENTS

Eleven patients with bulky recurrent colon cancer extending to adjacent organs or structures signed informed consent forms to receive IORT.

INTERVENTION

Of 10 patients who underwent exploratory laparotomy, 5 had no metastatic disease and underwent resection, IORT, and EBRT. Complete resection was accomplished in 4 patients. Doses of IORT ranged from 13 to 20 Gy depending on residual tumor burden; EBRT was typically delivered postoperatively to a dose of 45 Gy.

MAIN OUTCOME MEASURES

Survival and locoregional tumor control.

RESULTS

All 4 patients who underwent complete resection, IORT, and EBRT are alive without locoregional recurrence 53 to 77 months after treatment. Of these, only 1 patient developed distant metastases. The fifth patient, who had gross residual tumor, developed local recurrence 5 months after IORT. One patient developed an IORT complication-ureteral fibrosis leading to ipsilateral nephrectomy.

CONCLUSION

Long-term disease-free survival can be achieved in selected patients with bulky regional recurrence of colon cancer with complete tumor resection, IORT, and EBRT.