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J A Siegel

Publications and source records attributed to J A Siegel.

At least 19 recordsLinked to original sources
PubMed2005

The effectiveness of stand alone air cleaners for shelter-in-place.

UNLABELLED: Stand-alone air cleaners may be efficient for rapid removal of indoor fine particles and have potential use for shelter-in-place (SIP) strategies following acts of bioterrorism. A screening model was employed to ascertain the potential significance of size-resolved particle (0.1-2 microm) removal using portable high efficiency particle arresting (HEPA) air cleaners in residential buildings following an outdoor release of particles. The number of stand-alone air cleaners, air exchange rate, volumetric flow rate through the heating, ventilating and air-conditioning (HVAC) system, and size-resolved particle removal efficiency in the HVAC filter were varied. The effectiveness of air cleaners for SIP was evaluated in terms of the outdoor and the indoor particle concentration with air cleaner(s) relative to the indoor concentration without air cleaners. Through transient and steady-state analysis of the model it was determined that one to three portable HEPA air cleaners can be effective for SIP following outdoor bioaerosol releases, with maximum reductions in particle concentrations as high as 90% relative to conditions in which an air cleaner is not employed. The relative effectiveness of HEPA air cleaners vs. other removal mechanisms was predicted to decrease with increasing particle size, because of increasing competition by particle deposition with indoor surfaces and removal to HVAC filters. However, the effect of particle size was relatively small for most scenarios considered here. PRACTICAL IMPLICATIONS: The results of a screening analysis suggest that stand-alone (portable) air cleaners that contain high efficiency particle arresting (HEPA) filters can be effective for reducing indoor fine particle concentrations in residential dwellings during outdoor releases of biological warfare agents. The relative effectiveness of stand-alone air cleaners for reducing occupants' exposure to particles of outdoor origin depends on several factors, including the type of heating, ventilating and air-conditioning (HVAC) filter, HVAC operation, building air exchange rate, particle size, and duration of elevated outdoor particle concentration. Maximum particle reductions, relative to no stand-alone air cleaners, of 90% are predicted when three stand-alone air cleaners are employed.

Aerosols↗
PubMed2001

The long-term mental health consequences of child sexual abuse: an exploratory study of the impact of multiple traumas in a sample of women.

The current study examined exposure to multiple traumas as mediators of the relationship between childhood sexual abuse and negative adult mental health outcomes. Participants were 174 women interviewed in the third wave of a longitudinal study of the consequences of child sexual abuse. Child sexual abuse victims reported a lifetime history of more exposure to various traumas and higher levels of mental health symptoms. Exposure to traumas in both childhood and adulthood other than child sexual abuse mediated the relationship between child sexual abuse and psychological distress in adulthood. There were also some significant direct effects for child sexual abuse on some outcome measures. Results point to the importance of understanding the interconnected nature of trauma exposure for some survivors.

Adult↗
PubMed2001

Understanding links among childhood trauma, dissociation, and women's mental health.

Interrelationships among pathological dissociation, child and adult trauma exposure, and adult mental health symptoms were examined in a sample of low-income, mostly African-American women. Dissociation was significantly related to both trauma exposure and mental health symptoms but did not mediate this relationship. Implications for research and practice are discussed.

Adult↗
PubMed2001

Feasibility and safety of outpatient Bexxar therapy (tositumomab and iodine I 131 tositumomab) for non-Hodgkin's lymphoma based on radiation doses to family members.

Radioimmunotherapy with anti-CD20 antibodies is a promising treatment approach for relapsed low-grade non-Hodgkin's lymphoma. Under revised Nuclear Regulatory Commission regulations (May 1997), patients may be released following treatment provided the maximum dose to any individual is not likely to exceed 500 mrem. Non-Hodgkin's lymphoma patients have been studied to evaluate radiation exposure to caregivers/family members after outpatient treatment with tositumomab and iodine I 131 tositumomab (Bexxar therapy). Estimates of total radiation doses to individuals expected to be maximally exposed to patients posttreatment have revealed that the doses should be within revised guidelines. In a University of Nebraska Medical Center study, the predicted total radiation doses (based on patient dose rate at 1 meter) ranged from 95-423 mrem. Family members were provided radiation-monitoring devices to directly monitor radiation exposure. Measured doses ranged from 10-409 mrem. In this and other studies, estimated and measured dose equivalents to maximally exposed individuals were below 500 mrem. Measured doses were, in most instances, lower than those predicted by patient-specific calculations, thus confirming the validity of the calculated dose predictions. Therefore, radioimmunotherapy with tositumomab and iodine I 131 tositumomab can be safely conducted on an outpatient basis.

Antibodies, Monoclonal↗
PubMed2001

Contribution to red marrow absorbed dose from total body activity: a correction to the MIRD method.

UNLABELLED: The contribution to red marrow absorbed dose from beta-emitting radionuclides distributed uniformly in the total body can be overestimated using either MIRD 11 or MIRDOSE3. The S value assigned to the red marrow target region from activity distributed in the remainder of the body is of particular concern. The assumption that the specific absorbed fraction for total body irradiating red marrow and other skeletal tissues is the inverse of the total-body mass can result in an inappropriate remainder-of-body contribution to marrow dose. We evaluated differences in the calculation of marrow dose using MIRD 11 and MIRDOSE3 formulations and developed methods to correct the results from either to remove inappropriate contributions. When bone takes up significantly less activity than is predicted from an apportionment of remainder-tissue activity based on mass, the standard remainder-of-body correction may substantially overestimate the electron component of the S value from remainder tissues to red marrow using either MIRD 11 or MIRDOSE3. If bone takes up activity, this contribution is negligible using MIRD 11 S values but remains with MIRDOSE3 S values. This overestimate can be significant, particularly when the residence time of activity in the remainder of the body is much higher than in the red marrow and a different correction is needed. As the ratio of the remainder of body to marrow residence time is lowered, the overestimate becomes less significant. CONCLUSION: In this article, we show the magnitude of this overestimate (which is most important for nuclides with large "nonpenetrating" emission components and for pharmaceuticals that have a large ratio of remainder of body to marrow residence times), show the appropriate corrections to be made in each case, and propose a new method for calculating marrow dose contributions that will avoid this complication in future applications. Because all models give approximate doses for real patients, with uncertainties within those involved in these corrections, we do not suggest that changes be made to existing marrow dose estimates. We suggest only that future calculations be as accurate as possible.

Beta Particles↗
PubMed2001

Outpatient treatment with (131)I-anti-B1 antibody: radiation exposure to family members.

UNLABELLED: The Nuclear Regulatory Commission (NRC) regulations that govern release of patients administered radioactive material have been revised to include dose-based criteria in addition to the conventional activity-based criteria. A licensee may now release a patient if the total effective dose equivalent to another individual from exposure to the released patient is not likely to exceed 5 mSv (500 mrem). The result of this dose-based release limit is that now many patients given therapeutic amounts of radioactive material no longer require hospitalization. This article presents measured dose data for 26 family members exposed to 22 patients treated for non-Hodgkin's lymphoma with (131)I-anti-B1 antibody after their release according to the new NRC dose-based regulations. METHODS: The patients received administered activities ranging from 0.94 to 4.77 GBq (25--129 mCi). Family members were provided with radiation monitoring devices (film badges, thermoluminescent or optically stimulated luminescent dosimeters, or electronic digital dosimeters). Radiation safety personnel instructed the family members on the proper wearing and use of the devices. Instruction was also provided on actions recommended to maintain doses to potentially exposed individuals as low as is reasonably achievable. RESULTS: Family members wore the dosimeters for 2--17 d, with the range of measured dose values extending from 0.17 to 4.09 mSv (17--409 mrem). The average dose for infinite time based on dosimeter readings was 32% of the predicted doses projected to be received by the family members using the NRC method provided in regulatory guide 8.39. CONCLUSION: Therapy with (131)I-anti-B1 antibody can be conducted on an outpatient basis using the established recommended protocol. The patients can be released immediately with confidence that doses to other individuals will be below the 5-mSv (500 mrem) limit.

Ambulatory Care↗
PubMed2000

Proximal humerus malunions.

Malunion of a proximal humerus fracture often is painful and debilitating. Operative management of this deformity is technically demanding and frequently results in a relatively high rate of complications. Reconstruction involves a spectrum of procedures including excision of bony prominences, tuberosity osteotomy and realignment, and shoulder arthroplasty. This article covers the etiology, classification, diagnosis, and management of these complex injuries. A successfully performed reconstruction diminishes the patient's pain and potentially increases function.

Fractures, Ununited↗
PubMed2000

A generalized algorithm for determining the time of release and the duration of post-release radiation precautions following radionuclide therapy.

The Nuclear Regulatory Commission has recently amended its regulation concerning patients who have received therapeutic amounts of radioactivity. The amended regulation allows patient release based on a total effective dose equivalent (TEDE) limit of 5 mSv (500 mrem) instead of the activity administered or retained [1,110 MBq (30 mCi)] or the dose rate [0.05 mSv h(-1) (5 mrem h(-1)) at 1 m]. Record-keeping and written post-release radiation safety precautions are required, however. A general algorithm, combining patient-specific kinetics and dose rate measurements, has been developed to systematically determine the actual duration of post-release radiation precautions as well as the time of release post-treatment. This algorithm is based on the maximum permissible effective dose equivalents (MPEDEs) of the respective cohorts exposed, 5 mSv (500 mrem) to non-pregnant adult family members and 1 mSv (100 mrem) to pregnant women, children, and members of the general public. Operational equations to determine the times post-radionuclide treatment of release from medical confinement, of not working, of avoiding pregnant women and children, of limiting holding of children, and of sleeping partners not sleeping together have been derived and illustrated with a hypothetical example. TEDE-based release criteria should be less restrictive than the previous activity-based or dose rate-based release criteria. However, post-release radiation precautions may be more intrusive and longer in duration than those to which most practitioners have grown accustomed. Up to now, however, the duration (typically 1-2 d) of advised post-release precautions had not been rigorously derived from MPEDEs and were generally inappropriately short. Even so, dose-based release criteria should prove more cost-effective overall than hospitalization of patients commonly imposed by activity-based and dose rate-based release criteria.

Adult↗
PubMed2000

Effects of posture on gastric emptying and satiety ratings after a nutritive liquid and solid meal.

To study the effects of posture and meal structure on gastric emptying and satiety, nine women ingested tomato soup and then immediately or 20 min later an egg sandwich, when seated and when supine. The lag time was not different, but the half-emptying time of the sandwich was 32% longer (P < 0.01) and the emptying rate after the lag phase was 39% slower (P < 0.01) when the subjects were supine than when they were seated. The half-emptying time of the soup was 50% longer (P < 0.01) when the subjects were supine and ingested the soup immediately before the sandwich than in the other three conditions. Postprandial hunger ratings recovered more slowly (P < 0.01) when the subjects ingested the soup 20 min before the sandwich than when they ingested the soup immediately before the sandwich. These results suggest that posture did not affect the intragastric distribution of the sandwich but affected propulsion of the meal into the intestine and that postprandial satiety was enhanced by the cumulative effect over time of a 20-min "head start" in stimulation of intestinal receptors by emptying of the soup.

Adult↗
PubMed2000

Adult sexual revictimization among black women sexually abused in childhood: a prospective examination of serious consequences of abuse.

This study is a prospective investigation of adult sexual revictimization among 113 Black women with documented histories of childhood sexual abuse. The purpose was to obtain information on the frequency of sexual abuse in both childhood and adulthood and to determine which characteristics of the child sexual abuse were predictive of revictimization. Thirty percent of the participants were revictimized and physical force predicted subsequent victimization. This study also investigated possible sexual behavioral correlates of revictimization. Revictimized women reported more involvement in prostitution and partner violence. Finally, the present study considered the reproductive and sexual health correlates of revictimization. When compared to women abused in childhood only, revictimized women experienced more problems conceiving, repeated vaginal infections, sexually transmitted diseases, and painful intercourse. Suggestions for intervention are discussed.

Adolescent↗
PubMed2000

Functional and oncological outcome of acetabular reconstruction for the treatment of metastatic disease.

BACKGROUND: Metastatic disease of the acetabulum can be painful and disabling. Operative intervention is indicated for patients who fail to respond adequately to nonoperative treatment. We evaluated the functional and oncological outcome of acetabular reconstruction after curettage for the treatment of refractory symptomatic acetabular metastases. METHODS: Fifty-five patients with metastatic disease of the acetabulum were treated with operative acetabular reconstruction combined with a total hip replacement. The most common primary tumor was carcinoma of the breast (eighteen patients), followed by carcinoma of the kidney (seven patients) and carcinoma of the prostate (seven patients). Forty (73 percent) of the patients presented with multiple skeletal metastases, and eighteen (33 percent) had associated visceral metastases. Twenty-eight (51 percent) had severe pain requiring continuous use of narcotics, twenty-four (44 percent) had moderate pain requiring periodic use of narcotics, and the remaining three (5 percent) had mild pain requiring use of non-narcotic analgesics. Eighteen (33 percent) of the patients could not walk, twenty-three (42 percent) needed a walker or crutches, twelve (22 percent) used a single cane, and two (4 percent) walked without assistive devices. Intralesional curettage of the tumor was performed in all of the patients. Fifty-four of the hips were reconstructed with a protrusio cup and one, with a hemipelvis endoprosthesis. Large defects were reinforced with cement and pin or screw fixation (the modified Harrington technique), which allowed transmission of weight-bearing forces to the remaining intact pelvis. Thirty-six acetabular reconstructions were performed with antegrade pins or cannulated screws; fifteen, with long retrograde screws; and four, with cement. RESULTS: The median period of survival was nine months. Patients with visceral metastases had a median period of survival of three months compared with twelve months for patients without visceral metastases (p < 0.001). Patients with breast cancer presented later in the disease process (p < 0.004) and lived longer than did those with other carcinomas (p < 0.004). Forty-five patients were evaluated three months after reconstruction. Thirty-four (76 percent) of them had relief of pain as determined by decreased use of narcotics. Nine of the eighteen patients who could not walk preoperatively regained the ability to walk. Fourteen of the seventeen patients who originally were able to walk in the community retained that ability. Thirty-three patients were available for evaluation at six months. Twenty-five (76 percent) still had relief of pain, and nineteen (58 percent) were able to walk and function in the community. Overall, fourteen (25 percent) of the fifty-five patients had moderate local progression of the disease, and five of these patients had failure of the fixation. Fourteen early complications developed in twelve (22 percent) of the patients. One patient (2 percent) died perioperatively. CONCLUSIONS: Patients who have acetabular metastases that are refractory to radiation and chemotherapy have a short life expectancy. The early, gratifying results of reconstruction validate the role of operative treatment as a short-term palliative procedure. Protrusio acetabular cups presumably compensate for deficiencies of the medial wall, while cement and pin fixation can be used effectively to reconstruct large defects in the acetabular column and dome. The low rate of fixation failure supports the biomechanical principles of the reconstruction. Generally, the reconstructions are sufficiently durable to exceed the life expectancy of the patients.

Acetabulum↗
PubMed2000

Aggressive behavior among women sexually abused as children.

Although research shows that sexually abused children appear to be at risk of subsequent aggressive behavior, few investigations address whether such behavior persists beyond childhood. This research describes the self-reported adolescent and adult fighting behavior of 136 women sexually abused as children and examines the role of intervening variables in the risk of such behavior. The women are part of a longitudinal study of 206 primarily low-income, urban women whose abuse was documented at the time it occurred. Fighting was common, particularly during adolescence. Adult aggression was strongly associated with being a victim of violence by an intimate partner. A history of exposure to other forms of violence significantly increased the risk of fighting while strong maternal attachments mitigated the risk, primarily by reducing the likelihood of involvement in an abusive intimate relationship.

Adolescent↗
PubMed1999

Physeal response to absorbable polydioxanone bone pins in growing rabbits.

Absorbable fixation materials would seem especially useful for treating transphyseal fractures in growing children, but their degradation products may affect physeal growth. The histologic response of an open physis to placement of transphyseal, polydioxanone (PDS), bioabsorbable pins was studied in skeletally immature New Zealand White rabbits. A 1.3-mm PDS pin was inserted across the right femoral physis, and a 1.3-mm empty drill hole across the left femoral physis served as a control. The animals were sacrificed at 3, 6, 9, and 12 weeks postsurgery. Biplanar radiographs, bone length measurements, and histology sections of the physis and adjacent bone were made. Three independent observers graded the histologic response of the physis to the drilling and implant. There was no evidence of inflammation, foreign body reaction, or distortion of the growth plate during the entire growth period. This suggests bioabsorbable pins do not cause any appreciable inflammatory response or adverse effect on physeal function during active longitudinal growth of the bone.

Animals↗
PubMed1999

An analytical solution set for a four-compartment mixed mammillary/catenary model.

The purpose of this study was to extract the intercompartmental rate constants analytically from the coefficients and exponents of the exponential sum fitted to tracer data points for a unique four-compartment mixed mammillary/catenary (extended mammillary, radial) model, with losses solely from the central (blood) compartment. This model is useful in estimating myocardial and skeletal blood flow. Using Laplace transforms, the transfer functions of the exponential sum and the differential equations describing the model were obtained and the corresponding coefficients equated sequentially, which yielded the intercompartmental rate constants. Three solution sets of rate constants were found for the model, each of which satisfies both transfer functions. A program written in BASIC is provided, which requires only the coefficients and exponents of the exponential terms as input; the output is the three sets of rate constants. An example is given as an aid in debugging. Only one solution set of the three was physiologically realizable in the example, but the bounds defining these limits are not known. The advantages and limitations of the method are discussed. The method is suitable for initializing a non-linear least-squares fitting program for the rate constants. The appropriate physiological solution set for this model yields fractional and total myocardial or skeletal blood flow in a subject in the steady state.

Algorithms↗
PubMed1999

MIRD pamphlet no. 16: Techniques for quantitative radiopharmaceutical biodistribution data acquisition and analysis for use in human radiation dose estimates.

This report describes recommended techniques for radiopharmaceutical biodistribution data acquisition and analysis in human subjects to estimate radiation absorbed dose using the Medical Internal Radiation Dose (MIRD) schema. The document has been prepared in a format to address two audiences: individuals with a primary interest in designing clinical trials who are not experts in dosimetry and individuals with extensive experience with dosimetry-based protocols and calculational methodology. For the first group, the general concepts involved in biodistribution data acquisition are presented, with guidance provided for the number of measurements (data points) required. For those with expertise in dosimetry, highlighted sections, examples and appendices have been included to provide calculational details, as well as references, for the techniques involved. This document is intended also to serve as a guide for the investigator in choosing the appropriate methodologies when acquiring and preparing product data for review by national regulatory agencies. The emphasis is on planar imaging techniques commonly available in most nuclear medicine departments and laboratories. The measurement of the biodistribution of radiopharmaceuticals is an important aspect in calculating absorbed dose from internally deposited radionuclides. Three phases are presented: data collection, data analysis and data processing. In the first phase, data collection, the identification of source regions, the determination of their appropriate temporal sampling and the acquisition of data are discussed. In the second phase, quantitative measurement techniques involving imaging by planar scintillation camera, SPECT and PET for the calculation of activity in source regions as a function of time are discussed. In addition, nonimaging measurement techniques, including external radiation monitoring, tissue-sample counting (blood and biopsy) and excreta counting are also considered. The third phase, data processing, involves curve-fitting techniques to integrate the source time-activity curves (determining the area under these curves). For some applications, compartmental modeling procedures may be used. Last, appendices are included that provide a table of symbols and definitions, a checklist for study protocol design, example formats for quantitative imaging protocols, temporal sampling error analysis techniques and selected calculational examples. The utilization of the presented approach should aid in the standardization of protocol design for collecting kinetic data and in the calculation of absorbed dose estimates.

Humans↗
PubMed1999

The MIRD perspective 1999. Medical Internal Radiation Dose Committee.

The MIRD schema is a general approach for medical internal radiation dosimetry. Although the schema has traditionally been used for organ dosimetry, it is also applicable to dosimetry at the suborgan, voxel, multicellular and cellular levels. The MIRD pamphlets that follow in this issue and in coming issues, as well as the recent monograph on cellular dosimetry, demonstrate the flexibility of this approach. Furthermore, these pamphlets provide new tools for radionuclide dosimetry applications, including the dynamic bladder model, S values for small structures within the brain (i.e., suborgan dosimetry), voxel S values for constructing three-dimensional dose distributions and dose-volume histograms and techniques for acquiring quantitative distribution and pharmacokinetic data.

Humans↗
PubMed1999

MIRD pamphlet No. 17: the dosimetry of nonuniform activity distributions--radionuclide S values at the voxel level. Medical Internal Radiation Dose Committee.

The availability of quantitative three-dimensional in vivo data on radionuclide distributions within the body makes it possible to calculate the corresponding nonuniform distribution of radiation absorbed dose in body organs and tissues. This pamphlet emphasizes the utility of the MIRD schema for such calculations through the use of radionuclide S values defined at the voxel level. The use of both dose point-kernels and Monte Carlo simulation methods is also discussed. PET and SPECT imaging can provide quantitative activity data in voxels of several millimeters on edge. For smaller voxel sizes, accurate data cannot be obtained using present imaging technology. For submillimeter dimensions, autoradiographic methods may be used when tissues are obtained through biopsy or autopsy. Sample S value tabulations for five radionuclides within cubical voxels of 3 mm and 6 mm on edge are given in the appendices to this pamphlet. These S values may be used to construct three-dimensional dose profiles for nonuniform distributions of radioactivity encountered in therapeutic and diagnostic nuclear medicine. Data are also tabulated for 131I in 0.1-mm voxels for use in autoradiography. Two examples illustrating the use of voxel S values are given, followed by a discussion of the use of three-dimensional dose distributions in understanding and predicting biologic response.

Animals↗