Comparison of Native American births in upstate New York with other race births, 1980-86.

The purpose of this study was to describe the neonatal characteristics of Native American (Indian) infants and the antenatal characteristics of their mothers as compared with white, black, and other race infants. The study population comprised 979,444 live births to upstate New York (exclusive of New York City) resident mothers between 1980 and 1986. Data were abstracted from vital records (birth certificates) and analyzed using a variety of descriptive statistics. Mothers of Native American and black infants had similar antenatal profiles (that is, younger, higher parity, lower educational attainment, and delayed initiation of prenatal care), which differed from mothers of white or other race infants. Despite having at-risk mothers, Native American infants were similar to white and other race infants with respect to the percentage of births that were considered low birth weight or premature. Black infants were twice as likely as the other three groups of infants to be low birth weight or premature. These findings suggest that other factors appear to be important in determining neonatal outcome and that typical at-risk antenatal profile of mothers may not be consistent across all racial groups.


The hepatitis B immunization campaign for children in the Federated States of Micronesia.

Hepatitis B has long been recognized as hyperendemic among persons residing in the western Pacific. Effective control strategies have not been described. From December 1988 through October 1989, the Federated States of Micronesia (FSM) conducted a campaign to immunize children through age 6 years with three doses of hepatitis B (HB) vaccine. In addition, HB vaccination was incorporated into the routine immunization schedule for all children born in FSM, with the first dose given to newborns. Between December 1988 and October 1989, a total of 64,085 doses of HB vaccine were administered to the children. After the start of the campaign, the subject group was enlarged to include children through 15 years of age in the States of Yap and Kosrae. Fifty-nine percent of the enlarged group in all States received a complete series of HB vaccinations. During each client encounter, individual immunization records were examined and diphtheria-pertussis-tetanus, oral polio vaccine, and measles-mumps-rubella antigens were administered to children who were not adequately immunized. The annual immunization assessment for 1990 showed coverage improved significantly from previous years in every FSM State.


Factors influencing the effectiveness of mailed health surveys.

The authors investigated sources of bias in health surveys by examining responses to their 1989 questionnaire mailed to 1,255 Massachusetts men who were eligible for dental care provided by the Department of Veterans Affairs. After a maximum of three mailings and one telephone call to nonrespondents, a total of 1,049 veterans had responded out of 1,228 finally determined to be eligible, a response rate of 85 percent. The investigators found that small differences in univariate estimates would have occurred had the field phase been terminated after the first mailing, which had a response rate of 61 percent. To evaluate multivariate distributions, they duplicated their previously published logistic regression model for sources of dental care, using only those who responded to the first and second mailings. Although model fits would have been substantively the same had the field phase been terminated after the first or the second mailings, analysis of parameter estimates and their statistical significances suggested bias that would have led to different substantive conclusions, in some instances. Another potential source of bias in surveys was found to be item omission. Fifty-eight percent of respondents answered all 46 survey questions, and 90 percent answered at least 91 percent of the questions. Fewer questions were answered by those whose responses were received last, but trends regarding missing data by age or education were not statistically significant. Although the survey using this methodology met all objectives, subject nonresponses, the ineligibility of potential respondents, item nonresponses, and skewed distributions of outcome variables combined to reduce the statistical power to detect differences among groups or to alter the analysis of the differences. These factors need to be planned for by investigators undertaking similar surveys.


Effect of gum chewing following food ingestion on the pH of interproximal dental plaque.

Recent publications have suggested that chewing sorbitol- or sucrose-containing gum after a snack or meal can reduce development of caries by neutralizing dental plaque acids at interproximal sites in the dentition. To confirm these findings four volunteers wore appliances containing a miniature pH electrode. After plaque accumulation, subjects ingested a bowl of sugar-coated cereal with milk and 20 minutes later chewed a sorbitol-containing gum, a sucrose-containing gum, or did not chew anything for 20 minutes. After exposure to the cereal, the plaque pH fell within 20 minutes from approximately 6.4 to 4.8. Sorbitol gum caused the pH to rise to 5.5, while the sucrose gum caused the pH to rise to only 5.1. After cessation of chewing, the pH in all cases dropped to 4.5 or lower. No statistically significant difference could be shown between plaque pH changes with the various protocols. Gum chewing after eating caused only a transient elevation in plaque pH.


Restoration of endodontically treated teeth using a combined amalgam-composite resin technique.

This article describes a combined amalgam-composite resin technique for the restoration of endodontically treated molars suffering from severe, subgingival coronal damage. The use of silver amalgam in the subgingival areas provides an effective interface and a proper barrier for restoring and reinforcing the rest of the crown with a composite resin material.


Using after-shelter case management to improve outcomes for families with children.

Homelessness and living in shelters have complex and multiple adverse effects on children that lend urgency to assisting families with children to leave shelters and to achieve independent and stable living arrangements. Some shelters offer only short-term housing with no additional support services. Others offer long stays with a comprehensive range of social and economic support services. While living in a shelter, families are faced with such major challenges as finding employment that is adequate to meeting the family's financial needs and locating permanent housing. Because shelter or street living may exacerbate children's health and developmental problems, families with children should move from them into a stable home situation as quickly as possible. The researchers examined some of the specific effects of living in a shelter for homeless families with children in Virginia Beach, VA. They focused on whether the policy of offering families after-shelter case management services for 1 year decreased their average length of the time in the shelter, and whether case management of families with children for 1 year after leaving a shelter increased the proportion of families who obtained permanent housing. A non experimental descriptive design was used. In case management after the shelter stay, an advisor worked intensively with families, helping to locate resources and serving as a resource link, assisting with application processes, providing transportation when necessary, and acting as advocate and support person. Some families needed minimal assistance, while others needed more intensive assistance. The findings suggest that case management services for families following discharge from a homeless shelter effectively reduces the length of stay ina shelter and increases housing stability after discharge from the shelter. For this sample, the average shelter stay was reduced from 31.1 to 22.8 days.


Cigarette use among Arab Americans in the Detroit metropolitan area.

Use of cigarette tobacco by large proportions of the population of Middle Eastern countries has been reported; however, little is known about smoking behavior in one of America's fastest growing minorities, the Arab Americans. The purpose of this study was to examine cigarette smoking behavior of 237 randomly selected Arab American adults from a telephone listing in the Detroit area. Participants lived in the geographic Arab American community and identified with a Middle Eastern cultural heritage. Nurses, who spoke both English and Arabic, interviewed one adult family member using the 59-item self-report from the Cardiovascular Risk Factor Survey developed by Rice. Mean age of respondents was 40.4 years, 97 percent had been born in the Middle East, and 67 percent had been living in the United States 15 years or less. Current smokers rate was 38.9 percent, former smokers rate was 11.1 percent, never smokers rate was 50 percent, and the quit ratio (proportion of ever smokers who are former smokers) was 22.2 percent. Fifty-four percent of the current smokers were between 25 and 34 years of age; fewer women than men were former smokers, and the highest proportion of current smokers were Lebanese. Subjects who had smoked for the longest time were the least well educated. Arab Americans in this sample had a higher smoking rate, a lower quitting rate, and a much lower quit ratio when compared with national and State of Michigan data. With the growing numbers of Middle Eastern immigrants, there is potential for a dramatic increase in smoking-related health problems.


Dentin- and enamel-bonded Class V composite resin restoration.

Improvements in dental materials and methods of their use necessitate continuing modifications of clinical techniques. This paper details a step-by-step procedure for restoring a Class V carious lesion with polishable, visible light-polymerizing composite resin combined with one of the new-generation dentin-enamel bonding systems.


Bacterial infections and skin cleaning prior to injection among intravenous drug users.

In a survey of 1,057 active intravenous drug users in Baltimore, MD, who were recruited through extensive community outreach, 12 reported endocarditis and 113 reported subcutaneous abscesses in the 6 months before being interviewed. Of all the persons surveyed, 556 reported cleaning their skin prior to injection at any time and 173 reported cleaning their skin all the time in the 6 months before the interview. The frequency of subcutaneous abscesses was lower among those who reported skin cleaning all the time; a similar trend was noted for frequency of endocarditis. The relatively simple procedure of encouraging intravenous drug users to clean their skin prior to injection will not eliminate but might reduce the frequency of these serious and expensive infectious complications of intravenous drug use.


History, safety, and effectiveness of current bleaching techniques and applications of the nightguard vital bleaching technique.

This article reviews the literature on the use of hydrogen peroxide in three professionally administered bleaching techniques from historical, technique, and safety viewpoints. Safety over time, absolute safety, and relative safety of nonvital bleaching, in-office vital bleaching, nightguard vital bleaching, and over-the-counter bleaching kits are compared. The advantages and disadvantages of different bleaching options, as well as indications for individual or combined use of the techniques, are discussed. In addition, specific indications for the use of the nightguard vital bleaching technique are presented.


Effects of home bleaching products on composite resins.

A number of home bleaching products have recently been introduced. This in vitro study evaluated the effect of three representative bleaching products on the microhardness and surface texture of hybrid and microfilled composite resins. Scanning electron microscopic examination revealed cracking of the microfilled specimens treated with carbamide peroxide gels (Proxigel and White & Brite). White & Brite also caused slight roughening of the hybrid composite resin. Microhardness tests indicated that the treated composite resins became somewhat softer. However, the only statistically significant softening was associated with White & Brite.


Pneumatic versus hand condensation of amalgam: effect on microleakage.

This study compared two techniques of amalgam condensation for effect on early microleakage. Class V preparations were restored with a high-copper amalgam using pneumatic condensation or conventional hand condensation. Significantly less microleakage was observed when pneumatic condensation was used. Further, pneumatic condensation proved equally effective in reducing early microleakage whether or not a dentinal sealant was used as an intermediary.


Adaptation and condensation of amalgam restorations in Class II preparations of conventional and conservative design.

The purpose of this study was to investigate in vitro the adaptation and condensation of the proximal section of amalgam restorations placed in Class II preparations of conventional and conservative designs. The amalgam restorations were placed with traditional hand instruments with and without the aid of an automatic amalgam condenser. The restorations and sections of the restored teeth were examined and scored for adaptation and porosity. The restorations in the preparations of conservative design, especially those placed without the aid of the automatic condenser, exhibited more adaptation defects, porosity, and voids than did the restorations in the preparations of conventional design. It is necessary to identify and describe instruments and techniques that will facilitate the placement of amalgam restorations in preparations with limited access.


Microleakage of etched-dentin composite resin restorations.

Some clinicians now advocate dentinal etching to eliminate microleakage around composite resin margins. This study evaluated the "Kanca technique" and three commercial dentinal adhesives, including Clearfil Photo Bond, which uses phosphoric acid to etch dentin. The Kanca technique and Tenure were the most effective systems tested. However, none of the bonding systems completely eliminated microleakage. Total sealing of dentinal margins is not predictable with current adhesives and composite resins.


Periodontal changes in furcations resulting from orthodontic uprighting of mandibular molars.

Periodontal examinations were carried out preorthodontically and again 2 to 28 months after orthodontic uprighting of 20 molars (40 furcation areas) in 16 patients. Preorthodontically, patients presented with generalized periodontitis. Postorthodontically, nine of 20 buccal furcations had become more severe, one had improved, and ten remained unchanged. Lingually, nine worsened, and 11 had no change. Furcation area pocket depths increased in 35.0% of furcations, but did not change in 57.5%. Furcation root form was not associated with the degree of change. Possible mesial root extrusion was found in 60.0% of the uprighted molars. The molars showing root extrusion had furcations that increased in severity. Heavy uprighting forces contributed to extrusion, and some effect may have been due to periodontal inflammation and bone loss. Mandibular molars can be uprighted in patients with moderate periodontitis, but light intrusive forces in an inflammation-free environment are recommended.


Amalgam repair: a case report.

Through the report of a clinical case, the feasibility and advantages of repair and recontouring of complex amalgam restorations are discussed. In this patient, the kind of alloy used for the fractured restoration and the age of the restoration were known factors. Additional mechanical retention was prepared in both the "old" amalgam and the dentin, and the repair was made with a high-copper alloy. The bond at the repair site was stable at the 2.5-year recall examination.


Cermet reinforcement of a weakened endodontically treated root: a case report.

Many clinical applications have been recommended for glass-cermet cement because of its improved properties compared to the original glass-ionomer cements. It has also been accepted as a dentinal substitute that can strengthen teeth. In this paper, an additional clinical application for glass-cermet cement, the reinforcement of weakened endodontically treated roots, is suggested. This technique is in keeping with the trends of tooth conservation and the use of an adhesive restorative material in the restoration of severely damaged teeth by a conservative approach.


Tooth discoloration resulting from long-term tetracycline therapy: a case report.

Administration of tetracycline to children or pregnant women is known to adversely affect the color of developing teeth. This case report suggests the possibility that discoloration from tetracycline may not be limited to tooth development in the child, but may also affect the adult dentition. When given over long periods of time in adults, the tetracycline molecule is incorporated into the continuously forming secondary dentin. It is possible that chronic sun exposure of the incorporated tetracycline may cause the formation of a reddish-purple oxidation product, resulting in discoloration of the permanent teeth.


An update of a one-appointment master impression and jaw relation record technique.

Dentists may want to consider using an update of a unique complete denture technique that saves total chair time and, therefore, decreases cost. The technique combines appointments two and three, during which time the dentist both makes the master impressions and records the maxillomandibular relationships. In the past, protection of the maxillomandibular relationship records during the subsequent laboratory work was a problem. By applying new, tough, and thin denture base materials to the technique, the dentist will be less likely to distort the maxillomandibular records while boxing and pouring the impressions.


Origination and progression of microleakage in a restoration with a smear layer-mediated dentinal bonding agent.

Several recently marketed dentinal bonding agents modify, but do not remove, the smear layer. Some controversy exists as to whether the smear layer should be left in place or completely removed from preparations to be restored with composite resin systems. This study utilized scanning electron microscopy with energy dispersive x-ray analysis to evaluate the pathway of microleakage in a composite resin restorative material that utilizes a smear layer-mediated dentinal bonding agent. Microleakage occurred at the smear layer-dentin interface and progressed into both the smear layer and dentinal tubules, suggesting that the smear layer acts as a pathway for microleakage.


One-year clinical evaluation of an anterior composite resin.

An anterior composite resin was evaluated in a clinical study of 93 Class III and Class IV restorations placed in patients aged 12 to 50 years. The restorations were evaluated at baseline, 6 months, and 1 year. Sixty-four (79%) of the 81 restorations examined at the 1-year recall were unchanged. Marginal discoloration and changes in surface appearance and marginal adaptation accounted for most of the changes. All changes appeared in patients younger than 14 years, which may indicate that the patients had problems in oral hygiene. Replicas of randomly selected restorations showed smooth surfaces and well-sealed margins with a smooth transition from restoration to enamel. Some restorations showed marginal breakdown and a pitted irregular surface.


The shear bond strength between human enamel and composite resin placed with cured or uncured unfilled resin.

The shear bond strength between enamel and composite resin placed with an unfilled resin layer was tested under several conditions: The unfilled resin layer was either blown thin or left unthinned, and pre-cured alone or cured with the composite resin. Shear testing showed that the bond to enamel was slightly enhanced for Pekalux and was significantly enhanced for Durafill VS when the unfilled resin was not pre-cured. Thinning of unfilled resin slightly increased the bond strength of Pekalux and decreased the bond strength of Durafill VS. A majority of the specimens fractured at the composite resin-unfilled resin interface, and more than half of all interface failures occurred in specimens in which the unfilled resin had been pre-cured. The results indicated that the link between composite resin and the unfilled resin layer was enhanced by simultaneous curing.


Dry socket: frequency of occurrence after intraligamentary anesthesia.

To determine whether the use of intraligamentary anesthesia increases the incidence of dry socket, results of 305 extractions of mandibular molars in two groups of patients were studied. In the first group, inferior alveolar nerve block was applied, and, in the second, intraligamentary anesthesia was applied. A solution of 2% lidocaine with 1:80,000 epinephrine was used. Statistical analysis of the postoperative occurrence of dry socket indicated that the use of intraligamentary anesthesia did not result in a higher frequency of dry socket than did conventional anesthesia.


Dental caries and stress among South African political refugees.

The aim of this study, which was conducted in a refugee camp of the African National Congress in Tanzania, was to analyze the caries experience in relation to perceived stress and sleeping problems and stressful experiences among South African political refugees. A sample of 194 persons, aged 11 to 39 years, was examined clinically and interviewed. There was a consistent association between caries experience and the different parameters for estimating perceived and experienced stress. In particular, the aggregation of different stress indicators seemed be strongly related to higher caries experience.


Interaction between radiation and drug damage in mammalian cells. VI. Radiation and doxorubicin age-response function of doxorubicin-sensitive and -resistant Chinese hamster cells.

A comparative study of the radiation and/or doxorubicin (DOX) survival response for synchronous populations of Chinese hamster V79 cells and two DOX-resistant variants (77A and LZ-8) was performed. The greatest cellular radiation sensitivity was observed in mitosis, while the greatest resistance was observed during late S phase for the three cell lines. The variation in radiation response throughout the cell cycle was expressed as a change in the width of the shoulder of the survival curves (Dq) with little change in D0. This suggests that each phase of the cell cycle has a different capacity for accumulation of radiation injury. The radiation age-response function for the three cell lines revealed that 77A and LZ-8 cells were more radiosensitive than V79 cells throughout the cell cycle. Exposure of synchronous populations to DOX (1.84 microM for V79, 9.21 microM for 77A, and 921 microM for LZ-8) for 1 h as a function of cell cycle phase revealed that V79, 77A, and LZ-8 cells exhibited the greatest sensitivity to DOX in mitosis and the most resistance to DOX during S phase, as indicated by the differences in the slope of the initial component of the survival curve. Levels of P-glyco-protein (P-gp) are probably not a factor contributing to DOX age-response function since P-gp levels remain constant throughout the cell cycle in all three cell lines. Synchronous populations of V79, 77A, and LZ-8 cells sequentially treated with DOX and radiation at various cell cycle phases were also analyzed. The results showed that the interaction between radiation and DOX damage resulted in a reduced cellular capacity for the accumulation of radiation damage throughout the cell cycle, as indicated by a decrease in the width of the shoulder of the survival curve. Overall, both DOX-sensitive V79 cells and DOX-resistant 77A and LZ-8 cells exhibited (1) a similar age-response function for radiation or DOX, and (2) no differences in the effects of DOX on radiation-induced damage throughout the cell cycle. These results indicate that acquired resistance to DOX associated with increased levels of P-gp in the cell membrane did not appear to affect the age-response function for radiation or DOX, and the nature of the interaction between damage caused by radiation and DOX was also not affected.


Relative biological effectiveness of 50-MV X rays on jejunal crypt survival in vivo.

Earlier in vitro studies of relative biological effectiveness (RBE) of 50-MV X rays show an RBE of approximately 1.1 compared to 4 MV. No difference in RBE has been found for 20-MV X rays or 50-MeV electrons. The higher RBE for 50 MV can be explained to some extent by the small high linear energy transfer contribution from photonuclear reactions at high X-ray energies. To investigate the validity of the results in vitro, a study of the RBE of 50-MV X rays has been performed in vivo using the jejunal crypt microcolony assay in mice. The reference radiation used in this case was 20-MV X rays. The results confirm the earlier in vitro studies. The RBE for 50-MV X rays was estimated to be 1.06, calculated as the ratio between the slopes of the response curves.


The clonogen content of murine intestinal crypts: dependence on radiation dose used in its determination.

The number of colony-forming (clonogenic) cells in each of the crypts in mouse small intestine was deduced using a two-dose irradiation technique. The number was 7.5 +/- 0.8 cells using two equal doses each less than 9 Gy and 38 +/- 7 cells using 9 Gy or more per dose. The significant dose dependence could not be accounted for by considerations of intra- or intercrypt variability, or by the factor introduced to correct the sampling frequency for the influence of crypt size. The results suggest that more colony-forming cells may be recruited when the injury is more severe.


The effect of light fluence rate in photodynamic therapy of normal rat brain.

This paper reports the effect of incident light fluence rate on the depth to which necrotic lesions are produced by photodynamic therapy (PDT) in the brains of normal Fisher rats. The rats were injected intraperitoneally with Photofrin (12.5 mg kg-1) 48 h prior to PDT with a fixed incident fluence of 35 J cm-2. The treatment was performed at 10, 50, 100, and 200 mW cm-2 and also in a periodic manner (30 s "on" at 100 mW cm-2, 30 s "off"). The depth to which necrosis occurred was determined 24 h after treatment by microscopic examination of tissue sections. No differences were found in the depth to which necrosis was produced by any of the five irradiation schedules. This finding is discussed in the context of other published dose-rate experiments.


A comparison of the predicted risks of developing osteosarcoma for dogs exposed to 238PuO2 based on average bone dose or endosteal cell dose.

Dose-response relationships observed in laboratory animals can be used to identify possible human risk factors and may also be used in a quantitative manner when human data are not available. This paper presents an analysis of the dose dependency of osteosarcoma incidence in beagle dogs given a single inhalation exposure to a monodisperse aerosol of 238PuO2. We were particularly interested in comparing the predicted risks that were based on average bone dose with those based on endosteal cell dose and in evaluating the advantages of using a more biologically relevant cell-specific dose in risk estimation. The endosteal cell dose was calculated using the method of Marshall et al. (Health Phys. 35, 91-101, 1978), as extended to account for exposure by inhalation. The relationship between dose and time to tumor was analyzed by the proportional hazards regression model. The probability of developing osteosarcoma was strongly dependent on dose for dogs receiving low doses, but this was not true for dogs receiving high doses. The predicted risk based on endosteal cell dose was not consistently higher or lower than the risk based on average bone dose at various times after exposure, because the relationship between these two doses was not linear with respect to time. Also, as a result of the nonlinear relationship between these two doses, the risk estimated based on endosteal cell dose would not be a fixed factor of that based on the average dose. Random errors in the measured initial lung burden had a relatively large impact on the predicted risk based on endosteal cell dose, and the difference between the estimated risk of developing osteosarcoma based on endosteal cell dose and that based on average bone dose is likely to be within the error margins of the estimated risks.


Essential metalloelement metabolism and radiation protection and recovery.

Understanding the metabolism of essential metalloelements and their role in tissue maintenance and function as well as the roles of essential metalloelement-dependent enzymes in responding to injury offers a new approach to preventing and/or treating radiation injury. This review presents the roles of some essential metalloelement-dependent enzymes in the maintenance and function of tissues and their responses to radiation injury and gives an account of the observed effects of nontoxic doses of essential metalloelement compounds on protection against radiation damage and its recovery. The radiolysis of chemical bonds and free radicals derived from oxygen accounts for the acute and chronic aspects of radiation injury. The recognized biochemical roles of essential metalloelements and their observed pharmacological effects predict the therapeutic usefulness of essential metalloelement complexes in the prevention and/or treatment of radiation injury. Copper complexes have radiation protection and radiation recovery activities and cause rapid recovery of immunocompetence and radiation-induced damage to cells and tissues. Recently, iron, manganese, and zinc complexes have also been found to prevent death in lethally irradiated mice. These pharmacological effects of essential metalloelement complexes can be understood to be due to facilitation of de novo synthesis of essential metalloelement-dependent enzymes which have roles in preventing the accumulation of pathological concentrations of oxygen radicals or repairing damage caused by radiation-induced bond homolysis. Essential metalloelement complexes offer a physiological approach to prevention and/or treatment of radiation injury.


Comparisons of cellular radiation response using absolute rather than relative parameters.

One important goal of radiobiology is to describe the response to radiation damage in quantitative terms. Because the dose response is nonlinear, this typically involves the comparison of several dose-dependent parameters. Past attempts at simplifying this process have often involved manipulations of these dose-dependent parameters to derive a single comparative number. Unfortunately, the advantages of a single comparative number, often a ratio or even a ratio of ratios, can be outweighed by the loss of significant biological information. Examples are given in four areas of research: (1) definition of radiation response at clinically relevant radiation doses, (2) modification of radiation sensitivity by oxygen, (3) effects of combined radiation modifiers (e.g., sensitizers and protectors), and (4) comparisons of radiation modifiers in different dose/response regions. In each area, to define and compare dose response, we propose the use of consistent, simple, and absolute radiation response parameters: the inverse dose (or dose) required to produce a given effect. The use of absolute sensitivity (or resistance) avoids the use of many other parameters, ratios, and definitions and permits a uniform and unambiguous description of "radiation response."


Lymph flow from murine footpad tumors before and after sublethal hyperthermia.

The effect of local hyperthermia (43.5 degrees C for 1 h) on lymph flow from B16-F10 tumor-bearing foot pads of C57BL/6 mice was measured by monitoring the clearance of 99mTc-labeled human serum albumin. The foot was represented by a single-compartment model enabling a quantitative computation of lymphatic flow from the tumor to regional lymph nodes. Lymphatic flow from untreated tumors was 0.0059 +/- 0.0011 ml/min cm3 compared to 0.0118 +/- 0.0027 ml/min cm3 lymphatic flow from tumors immediately following heating. Morphological alterations in tumor blood vessels result in their high vascular permeability. The increase in lymphatic clearance from tumors after sublethal hyperthermia is compatible with the increase in interstitial fluid formation in tumors based on Starling's Law.


Radiation-induced micrencephaly in guinea pigs.

The effect of X rays on brain weight of guinea pig pups at birth was studied in 21-day-old embryos exposed in utero to doses of 75 and 100 mGy. When compared to controls and when corrected for body weight, gestation time, litter size, sex, and examiner differences, the brains of irradiated pups weighed approximately 46 mg less than those of controls (P < 0.001) for the 75-mGy group and about 55 mg less for the 100-mGy group. Brains of females weighed 51 mg less than those of males of the same body weight. Dam weight and caging conditions had no observed effect on brain weight.


Effects of the calcium channel blocker flunarizine on the hemodynamics and oxygenation of tumor microvasculature.

Flunarizine is a diphenylpiperazine calcium entry blocker that has been shown previously to increase tumor blood flow and sensitivity to radiotherapy via reduction in the radiobiologically significant hypoxic fraction. Two mechanisms of action have been proposed previously (vasodilation, altered blood viscosity), but no studies have been performed to examine its mechanisms of action in vivo. Such information would be invaluable in determining the role of flunarizine in multimodality approaches to reduce tumor hypoxia. Fisher-344 rats bearing R3230Ac tumors transplanted into dorsal flap window chambers were used to examine microcirculatory changes after administration of flunarizine (1.0 mg/kg, iv). The drug increased the diameters of the microvasculature and red cell velocities specifically in central tumor regions (producing an average increase in vessel flow by a factor of 1.96), which was accompanied by an increase in perivascular pO2 of 12 mm Hg, on the average. The drug did not change the diameters of tumor "feeding" vessels, nor did it change vascular length densities. Thus the improvement in central tumor blood flow and oxygenation could not be attributed to dilation of feeding vessels. The oxygen-carrying capacity of the blood was not altered either since hemoglobin saturation (measured in vitro) and the hematocrits of the microvasculature were unchanged after drug administration. Therefore, by a process of elimination, the most likely explanation for the effect of the drug is modification of blood viscosity. Additional studies are under way in this laboratory to examine whether changes in viscosity occur after flunarizine administration.


The effect of superhelical density on the yield of single-strand breaks in gamma-irradiated plasmid DNA.

Using agarose gel electrophoresis, the formation of DNA single-strand breaks (SSBs) by 137Cs gamma irradiation was quantified in negatively supercoiled topological isomers of plasmid pUC18. The G value for SSB formation falls slightly from 1 x 10(8) to 8 x 10(-9) SSB Gy-1 Da-1 as the superhelical density varies from 0.00 to -0.08. This result is not in agreement with recent observations by others which suggest that increasing the negative superhelical density of plasmid DNA increases its sensitivity to X irradiation.


Radiation-induced inactivation of dihydroorotate dehydrogenase in dilute aqueous solution.

The inactivation of dihydroorotate dehydrogenase by gamma irradiation in dilute aqueous solution has been investigated. The activity of the enzyme decreased exponentially as a function of the absorbed dose under aerated and nitrous oxide-saturated conditions. The contributions of the individual radical species derived from water radiolysis were estimated from the inactivation results observed under aerated, argon-saturated, and nitrous oxide-saturated conditions. The hydrogen atom and hydroxyl radical were found to be important in enzyme inactivation. The effect of selected inorganic radical anions such as Br.2-, I.2-, and (SCN).2- on the enzyme activity was also studied, and the results implicate the possible involvement of cysteine and tyrosine residues in the catalytic activity of dihydroorotate dehydrogenase. Changes in the kinetic parameters (Michaelis-Menten constant, Km, and maximal velocity, Vmax) due to irradiation under the conditions investigated suggest that radiation-induced inactivation is due to modification of the substrate binding sites and that of the active site residues in the enzyme. Evidence for the reduction of iron-sulfur centers in the enzyme during the inactivation process has been put forward from the difference spectrum of the irradiated dihydroorotate dehydrogenase. It has also been shown by electrophoretic studies that radiation-induced inactivation was not due to any fragmentation of the protein structure or the formation of any intermolecular crosslinking.


Thrombopoietin from human embryonic kidney cells causes increased thrombocytopoiesis in sublethally irradiated mice.

Previous work showed that mice treated with platelet-specific antiserum prior to whole-body irradiation did not suffer the degree or duration of thrombocytopenia as did irradiated control mice. We now report that a partially purified preparation of a thrombocytopoiesis-stimulating factor (TSF or thrombopoietin) mimics the biological effects of platelet-specific antiserum treatment in hematopoietically suppressed mice. Male C3H mice were exposed to 3.0 or 4.5 Gy of 137Cs gamma radiation and injected with a total dose of 4 units (U) of TSF. Human serum albumin (HSA) and rabbit anti-mouse platelet serum-injected mice, along with unirradiated mice, served as controls. Packed cell volumes (PCV), RBC counts, WBC counts, platelet counts, and percentage 35S incorporation into platelets were measured in mice at various days (7-14) following treatment. The results showed that irradiated mice treated with TSF had increased 35S uptake into platelets and higher platelet counts than HSA-treated controls. Also, PCV, RBC counts, and WBC counts of irradiated mice treated with TSF were significantly higher than values for HSA-treated mice. Additional experiments using 40,000 U/mouse of Interleukin-6 (IL-6), 227 U/mouse of granulocyte macrophage-colony stimulating factor (GM-CSF), or a combination of GM-CSF and IL-6 did not show increased platelet counts or 35S incorporation into platelets on Days 10 and 14 when compared to other mice treated with control substances. These results suggest that the radioprotective effects of platelet antibodies reported previously may be due to the release and action of thrombopoietin. These studies also demonstrate that thrombopoietin therapy will modulate the severe thrombocytopenia that occurs in radiation-induced bone marrow suppression.


Repopulation of O-2A progenitor cells after irradiation of the adult rat optic nerve analyzed by an in vitro clonogenic assay.

In the central nervous system (CNS) O-2A (Oligodendrocyte type 2 Astrocyte) progenitor cells have been proposed as potential target cells, and their depletion by irradiation will cause demyelination. The extent and time course of repopulation of these glial stem cells were studied in the adult rat optic nerve after irradiation in vivo. The number of O-2A progenitor cells was measured quantitatively by an in vitro clonogenic assay. Although the CNS is typically a late-responding tissue, repopulation was initiated almost immediately after irradiation and after several weeks a plateau was reached that lasted up to 6 months. Single doses of 4-12 Gy of X rays caused a permanent reduction in the number of O-2A progenitor cells. An analysis of the colony size of O-2A progenitor cells showed a sustained reduction in the number of offspring of cells surviving a dose of 12 Gy. In addition, the colony size of unirradiated progenitors diminished with increasing age of the animals.


Identification of nitroxide radioprotectors.

The nitroxide Tempol, a stable free radical, has recently been shown to protect mammalian cells against several forms of oxidative stress including radiation-induced cytotoxicity. To extend this observation, six additional water-soluble nitroxides with different structural features were evaluated for potential radioprotective properties using Chinese hamster V79 cells and clonogenic assays. Nitroxides (10 mM) were added 10 min prior to radiation exposure and full radiation dose-response curves were determined. In addition to Tempol, five of the six nitroxides afforded in vitro radioprotection. The best protectors were found to be the positively charged nitroxides, Tempamine and 3-aminomethyl-PROXYL, with protection factors of 2.3 and 2.4, respectively, compared with Tempol, which had a protection factor of 1.3. 3-Carboxy-PROXYL, a negatively charged nitroxide, provided minimal protection. DNA binding characteristics as studied by nonequilibrium dialysis of DNA with each of the nitroxides demonstrated that Tempamine and 3-amino-methyl-PROXYL bound more strongly to DNA than did Tempol. Since DNA is assumed to be the target of radiation-induced cytotoxicity, differences in protection may be explained by variabilities in affinity of the protector for the target. This study establishes nitroxides as a general class of new nonthiol radioprotectors and suggests other parameters that may be exploited to find even better nitroxide-induced radioprotection.


Radioprotection of DNA in isolated nuclei by naturally occurring thiols at intermediate oxygen tension.

Incubation of isolated Chinese hamster ovary cell nuclei, equilibrated in an atmosphere containing 2% O2, with glutathione, cysteine, or cysteamine resulted in a decrease in the number of X-ray-induced DNA double-strand breaks (DSBs), determined by pH 9.0 filter elution. In the absence of exogenous thiol, no sensitization was observed with the addition of N-ethylmaleimide, indicating that endogenous thiols were not present at significant levels. Protection by 0.3 mM glutathione was not enhanced by the addition of exogenous glutathione S-transferases or by glutathione peroxidase. The data were analyzed according to a simple competition model with various hypotheses. Cysteamine was more than an order of magnitude more effective than the other thiols tested, on a molar basis, in preventing DSB formation. Depending on the hypothesis used to evaluate the data, glutathione was either much less effective, on a molar basis, in preventing the bulk of the DSBs or was capable of preventing only approximately 55% of the damage, regardless of concentration. These data suggest that natural thiols other than glutathione may contribute to cellular radioprotection even if their concentration is much lower than that of glutathione. The data also suggest that despite the relative inefficiency of glutathione as a radioprotector, some areas of oxygenated tissues--where the oxygen tension falls below 2%--may be protected by glutathione concentrations in the physiological range of 3-20 mM.


[The functional status of the hypophyseal-adrenal cortical adaptation system in children in Byelarus living under the action of low doses of radiation after the accident at the Chernobyl Atomic Electric Power Station].

The analysis of the status of sympatho-adrenal and hypophysis-adrenal medulla systems of adaptation in children living in territories contaminated by radionuclides was carried out. A decrease in the catecholamine level in children's urine and hyperactivity of the hormonal response of adrenal medulla to endogenous ACTH indicated the reduced ability of adaptation and decreased resistance of children's organisms to stress factors of the environment.


[The effect of iodine-131 on the binding characteristics of sex and thyroid hormones by blood plasma proteins in children with a functional thyroid disorder as a result of the accident at the Chernobyl Atomic Electric Power Station].

In studying characteristics of specific interaction of estradiol-, testosterone- and thyroid-binding blood globulins with the corresponding ligands in children from Gomel Province with endemic swelling of the thyroid gland (degrees I and II) affected by iodine-131 revealed were a reduced cooperativity in estradiol and T-3 binding and a halved affinity to androgens and thyroids as compared to healthy controls. In addition, there was a drastic decline in the binding capacity of estradiol- and testosterone-binding globulins in the blood plasma. The endemic thyroid gland swelling is supposed to be due to sexual malfunction in teenagers.


[Radiation reactions and the possibilities for their modification in rats exposed in the area of the Chernobyl Atomic Electric Power Station].

A study was made of some embryological, hematological, cytogenetic and biochemical characteristics in Wistar rats exposed within the Chernobyl NPP zone over a period of 30 days (the average radiation background level, 75, and at the soil surface, 115 mR/h; a cumulative dose, 57 rad/30 days, and for pregnant rats, 36 rad/20 days). The quantity of chromosome aberrations in bone marrow metaphases and the embryonal death rate were invariable; some cases of teratogenesis were, however, observed. The total number of karyocytes in the brain and the leukocyte content in the peripheral blood sometimes decreased. The changes in certain characteristics (such as the content of endogenous amines and thiols in the liver and spleen) of the endogenous radioresistance background (ERB) and the normalization of the ERB by the radioprotective agent MIGI-K were found.


[Chromosome aberration induction in murine spermatocytes in joint exposure to radiation and sodium nitrite and nitrate].

In studying the combined effect of single and fractionated exposure to gamma/neutron radiation (12.5-50 cGy) and sodium nitrite (100 mg/kg) and chronic irradiation with a mixture of radiation (25 cGy) and sodium nitrite, nitrate (10-100 mg/l) the synergistic effect was observed in inducing reciprocal translocations in mouse spermatocytes. The dose-response function of the reciprocal translocations occurrence in Af mouse spermatocytes was nonlinear; there was a "plateau" within the dose range from 25 to 50 cGy.


[The role of the thyroid hormones in regulating chromosomal resistance to microwave exposure].

The mutagenic effect of microwaves (2450 MHz, 500 mu W/cm2, 30 days, 7 h/day) on rats was shown to decrease under the influence of thyroxine (2.5 mu g/100 g) administered over a two-week period. The major role of thyroid hormones in the formation of the antimutagenic effect of nonionizing radiation (2450 MHz, 10 mu W/cm2, 30 days, 7 h/day) was confirmed by the experiments with the parathyroid gland being removed.


[The quantitative patterns in the yield of chromosome aberrations in a human lymphocyte culture under fractionated gamma-neutron irradiation at different stages of the mitotic cycle. The cytogenetic effects at the G0 stage].

A study was made of the quantitative regularities of the interaction of cytogenetic damages induced, at the G0 stage of human lymphocyte culture, by fractionated gamma-neutron radiation, within a wide range of doses, delivered in the direct of reverse sequence at the intervals between fractions of 1 and 5 h. The results were compared with those obtained in experiments with single and fractionated gamma- or neutron irradiation within the same dose range.


[The inhibition by the tumor necrosis factor of the death and DNA fragmentation of lymphoid cells in irradiated rats].

The influence of a tumor necrosis factor, administered 16 h before irradiation of rats, on the radiation response of thymus and bone marrow cells has been investigated. Three and 6 h after irradiation the following indices were analyzed: the number of apoptotic cells in the thymus; the accumulation of polydeoxyribonucleotides and the appearance of single-strand breaks in DNA of bone marrow and thymus cells; and the electrophoretic properties of thymocyte DNA. The injection of a tumor necrosis factor reduced the number of polydeoxyribonucleotides, inhibited internucleosome DNA fragmentation, and did not influence the formation of single-strand breaks in DNA.


[The effect of one-time external gamma irradiation at different stages of ontogeny on the thyroid status of rats].

A single external gamma-irradiation (1 Gy) of rats on day 35 of their life causes stable structural and functional disturbances in the thyroid gland leading to the development of hypothyrosis at the remote times following irradiation which is demonstrated by the decrease in the concentration of thyroxine in the blood, increase in the thyrotropic function of the hypophysis and inhibition of the activity of tyrosine-dependent enzyme, alpha-glycerophosphate dehydrogenase, in the liver. Disturbances induced by such exposure in the thyroid gland of adult rats are insignificant and compensatory in time.


[The effect of gamma irradiation at sub- and supralethal doses on the lipid composition of the mucosa and of the brush border membrane of the small intestine in rats].

A study was made of the amount of cholesterol and its ethers (phosphatidyl choline, phosphatidyl ethanolamine, sphingomyelin, phosphatidyl serine, and phosphatidyl inositol) in mucosa and membrane of the small intestine brush border 24 h after 4 Gy and 2 h after 20 Gy irradiation. No changes in the lipid content of mucosa and membrane of the brush border were noted after 4 Gy irradiation. Exposure to 20 Gy radiation doubled the number of cholesterol ethers and made the number of individual phospholipids and cholesterol increase by nearly 1.5 times. The amount of phosphatidyl serine in the brush border membrane increased by almost 3 times; the concentration of other lipids increased by nearly 1.5 times; cholesterol/phospholipid ratio was unchangeable.


[The individual postradiation reactions of cyclic nucleotides in the lymphoid cells of the rat spleen].

X irradiation (4.3 Gy) of rats was shown to cause different reactions of the cyclic nucleotide system in differently reactive animals which was determined by the neutrophilic response in the peripheral blood after three-hour immobilization. Changes in the cyclic nucleotide content and in the activity of adenylate cyclase were found to occur in both hyper- and hyporeactive animals 24 h after irradiation. In hyperreactive animals, however, these changes were more pronounced: a relative ability of adenylate cyclase to be activated in hyperreactive animals made 30%, and 52% in hyporeactive animals. The cAMP content in lymphocytes of the spleen of hyporeactive rats was twice as high as that in hyperreactive animals.


[The effect of ionizing radiation on nitrosamine formation from anthropogenic precursors].

The kinetics of formation of nitrosoamines from precursors under the effect of ionizing radiation has first been quantitatively estimated, and the optimal conditions of their formation determined. The possibility of formation of nitrosoamines under the effect of low-level radiation has been investigated. Using the mathematical functions obtained from the experiments, the number of nitrosoamines, that may form under the effect of radiation in the aqueous medium, has been determined.


[Changes in cellular radiosensitivity by modifying the cytoplasmic membranes].

The radiosensitivity of mouse myeloma and E. coli cells in the presence of Mg2+ and UO2(2+) ions has been investigated. It has been shown that Mg2+ ions (10(-4) M) do not influence the viability of E. coli and mouse myeloma cells. The presence of Mg2+ ions during irradiation reduces the survival rate of E. coli cells, but the addition of Mg2+ ions after irradiation does not influence the radiosensitivity of E. coli cells. Comparison of the results on the influence of Mg2+ ions upon cells and bilayer lipid membranes (BLM) permits us to suppose that Mg2+ ions increase the positive charge of the membranes thus promoting the increase in the number of short-lived radiolysis products which impair membranes and increase cell radiosensitivity. UO2(2+) ions (10(-4) M) increase the radioresistance of E. coli cells which can be associated with the increase in the lateral membrane viscosity, as it was shown in the studies on BLM.


[The effect of ionizing radiation at superhigh doses on the processes of dopamine release and reuptake by nerve endings in different sections of the brain].

Rats exposed to fast 24 MeV electrons (100 Gy) at the state of early transient incapacity (ETI) exhibited active release and reuptake of dopamine in nerve terminals of the striatum. No changes in the indices under study were found in rats exposed to 25 Gy radiation that did not cause the ETI development. The in vitro irradiation of the isolated synaptosomes (100 Gy) inhibited dopamine reuptake and increased the number of sites of 3H-spiperone binding to D2-receptors in a membrane fraction isolated from the striatum.


[The effect of the immunomodulator glucosaminylmuramyl dipeptide on hematopoiesis in mice with experimental cytopenia].

Simulation of cytopenia by injection of cyclophosphamide (100 mg/kg) or by exposure to ionizing radiation (4 Gy) was shown to cause in mice similar, by the severity and rate of development, transient inhibition of haemopoiesis which was somewhat more persistent after irradiation. Glucosaminylmuramyl dipeptide applied after the above effects promoted the haemopoiesis recovery.


[The effect of gas hypoxia (10% O2) and dextran sulfate on the radiosensitivity of the stem cells of the intestinal epithelium in mice].

Injection of dextran sulphate before irradiation was shown to protect jejunal epithelium stem cells (D0 increased from 1.13 to 1.82 Gy). The protective effect of a combination of dextran sulphate and gas hypoxic mixture (10% O2) did not exceed that of the administration of the gas hypoxic mixture (10% O2) alone.


[The circadian oscillations in the radioresistance of the CNS in female and male rats after craniocaudal gamma radiation].

In experiments with albino mongrel male and female rats subjected to craniocaudal gamma irradiation (60Co, 62.5 Gy), daily oscillations of the CNS radioresistance were revealed by the criterion of occurrence of early transient neurological disorders (ETND). Experiments were conducted during two seasons (January and April). The time factor was significant, as estimated by the frequency and severity of opisthotonos and convulsions in males. ETND were more frequent and severe in females than in males.


Clinical overview of occupational lung disease.

The workplace has been a source of lung injury for centuries, yet awareness of the types of injuries has varied over time. Because of distinctive differences among the occupational lung disorders, a continual update of the clinical findings, dose response data, physiologic characteristics, and radiographic findings is needed. The radiologist plays a key role for the evaluation of miners, foundry or factory workers exposed to mineral dusts, and of workers exposed to the "biologic" dusts, infectious agents, cancer causing agents, and chemicals causing interstitial lung diseases. This overview includes a discussion of classification systems, criteria for diagnosis of occupational lung diseases, the pulmonary clinician's evaluation, and important aspects of specific disorders and concludes with a discussion of pulmonary disability determination.


The 1980 ILO classification of radiographs of the pneumoconioses.

The 1980 ILO classification of radiographs of the pneumoconioses has undergone revision and improvement in response to increases in knowledge and international concerns. Its goal is to standardize the reading and reporting of radiographic manifestations of the inhalation of dust so that international epidemiologic comparisons are possible. It remains an imperfect instrument, but "... although total elimination of variation is impossible, some measure of control can be achieved."


Standard imaging in silicosis and coal worker's pneumoconiosis.

Silicosis and coal worker's pneumoconiosis (CWP) are two relatively common occupational diseases. Silicosis is the most common pneumoconiosis in the United States. It results from inhalation of the particulate form of quartz or other crystalline forms of silicon dioxide with a diameter of less than 5 micrograms. CWP is the result of inhalation of carbon particles. Pathologic features of the two diseases differ, yet their radiologic features are identical. Simple pneumoconiosis is characterized by multiple small rounded opacities of 1 to 5 mm in diameter and with a bias for the upper lung zones. Complicated pneumoconiosis results from confluence of small opacities into large opacities that form conglomerate masses or progressive massive fibrosis.


Computed tomographic evaluation of silicosis and coal workers' pneumoconiosis.

The introduction of computed tomography (CT) has modified the radiologic approach to silicosis and coal worker's pneumoconiosis considerably, allowing earlier recognition and more precise characterization of pulmonary abnormalities than chest radiography. An optimal approach to CT recognition requires an understanding of the main physiologic and pathologic features that are known to occur in both pneumoconioses. This report focuses on the most common CT features of simple and complicated forms of silicosis and coal worker's pneumoconiosis as well as on the optimal scanning protocol. The respective roles of chest radiographs and CT scans in the recognition of pneumoconiosis and follow-up of exposed workers are discussed.


Conventional radiography in the diagnosis of asbestos-related disease.

Standard chest radiography, despite its limitations, remains an important means of evaluating the asbestos-exposed worker. Because of its wide availability, low radiation dose, and low cost, it will continue to be the standard imaging procedure for the screening of asbestos-exposed populations.


Computed tomography in the evaluation of benign asbestos-related disorders.

High-resolution CT is more sensitive than chest radiography and conventional CT in the detection and assessment of benign asbestos-related pleural and parenchymal diseases. The HRCT features of asbestosis correlate with clinical and functional restriction. The specificity of HRCT findings of asbestosis needs further evaluation. Given its low cost and availability, chest radiography remains the mainstay of imaging in benign asbestos-related diseases. CT (conventional or high-resolution) is not recommended as a universal screening test in asbestos-exposed workers. It has a useful role in identifying and quantitating pulmonary fibrosis distinct from emphysema and pleural disease, in distinguishing pleural disease from normal extrapleural soft tissues, and in clarifying the confusing chest radiograph or conflicting pulmonary function data. CT is useful in excluding a mass that may be obscured by extensive pleural and parenchymal fibrosis and is helpful in the follow-up of benign fibrotic masses or in the direction of their biopsy.


Chronic beryllium disease.

Chronic beryllium disease is a multisystem granulomatous disease caused by industrial exposure to beryllium dust or fumes. It is thought to represent a hypersensitivity disorder rather than a true pneumoconiosis. The lung is the primary organ of involvement, and many of the radiographic features resemble sarcoid.


[The effect of gamma irradiation on the direct intercellular interaction (rosette formation) of thymic macrophages with thymocytes].

In experiments with (CBA x C57BL/6)F1 mice, the effect of radiation on rosette formation between thymus macrophages (Th-MPh) and thymocytes (Thc) was studied on days 1, 4, 12, 30, and 60 following gamma irradiation with doses of 0.5, 2, 4, and 8 Gy. The influence of supernatants of thymus epithelial cells (EC) on the rosette formation was estimated. Gamma irradiation with doses of above 2 Gy was shown to cause a dose-dependent inhibition of rosette formation of Th-MPh with Thc in vitro. Recovery of rosette-forming ability of Th-MPh was observed on day 60 of the experiment. Two types of rosette-forming Th-MPh were identified: RFMPhII with low rate of binding to Thc and RFMPhII with high rate of binding to Thc. Radiation affects mainly the RFMPhII content. With radiation doses of 4 and 8 Gy no complete restoration of RFMPhI was observed on day 60. The total population of rosette-forming Th-MPh was restored on day 60 mainly due to cells with low rate of rosette formation. The EC supernatant promoted rosette formation of exposed Th-MPh with Thc. The effect was maximum at early times following irradiation of Th-MPh with a dose of 4 Gy.


Hypersensitivity pneumonitis.

Hypersensitivity pneumonitis is an immunologic mediated response in the lung to inhaled organic antigen. Farmer's lung and pigeon breeder's lung are the two most widely know disorders. The chest radiograph usually is normal in hypersensitivity pneumonitis. When abnormal, the distribution of disease favors the lung bases with acute disease and the upper lung zones with chronic disease. Computed tomography (CT) may be more sensitive in detecting parenchymal abnormalities, although the characteristic findings of hypersensitivity pneumonitis at CT or high-resolution CT are nonspecific.


[The effect of ionizing radiation on the vascular bed of the skin in ontogeny. The function of the microcirculatory bed of the skin in the fetuses of white rats sublethally irradiated].

Albino female rats were exposed to X radiation (5 Gy, 180 kV, 10 mA, filter 0.5 mm Cu) on days 10-15 of pregnancy. After 3 and 7 days they were sacrificed (under ether anesthesia) and fetuses were extracted. The status of the lympho- and hemomicrocirculatory beds (LMCB and HMCB) of the fetus back skin was studied by the macro- and microscopic methods. As early as day 3 of radiation sickness the diameter of LMCB vessels increased by 1.4-1.9 times, whereas changes in GMCB were less pronounced. On day 7, there was a progressive increase in dilatation of LMCB vessels, alongside with the narrowing of large units (arteries and veins). The development of the connective framework of the fetus skin was retarded.


[The distribution of intratracheally administered plutonium-239 throughout the skeletal bones].

The data are presented on distribution of the intratracheally administered plutonium-239 within the skeleton bones. Plutonium was found to be distributed non-uniformly within the skeleton: it was concentrated mainly in the bones where the trabecular fraction of the bone tissue was most manifest. The results obtained were supported by the correlation analysis.


Chemical pneumonitis.

Many organic and nonorganic agents can cause chemical pneumonitis. The more soluble agents tend to involve the upper respiratory tract, whereas less soluble agents reach the distal airways, causing pulmonary edema. The initial chest radiograph can be normal for as long as 48 hours, therefore delayed radiographs are important in significant exposures. The most common radiographic pattern is pulmonary edema, although various radiographic opacities have been reported. Acute complications include secondary pneumonia. Long-term complications include bronchiectasis, bronchiolitis obliterans, and lung destruction.


Occupationally induced neoplasms of the lung and pleura.

The relationship between asbestos and mesothelioma has been well delineated in the past. The epidemiologic, clinical, radiologic, and pathologic features of mesothelioma are discussed with reference to the diagnostic evaluation of asbestos-exposed patients. The extensive epidemiologic data correlating asbestos, tobacco smoke, and induction of lung carcinoma are also reviewed. These data provide a model for evaluation of other occupationally induced lung carcinogens such as organic and metallic industrial inhalants.


Alternate AP knee method assures open joint space.

An alternate method of imaging the knee in the AP projection assures diagnostic joint spaces to provide optimal diagnostic information. The degree of angulation is varied from 5 degrees cephalic to 5 degrees caudal and is determined by measuring the patient's anterior superior iliac spine to table-top distance.


A comparison of student radiographic reject rates.

Educators and administrators often are called upon to estimate the economic considerations of students in radiology departments for clinical education. Yet, little has been written about student radiographic reject rates. This study assessed the radiographic reject rate of 320 first- and second-year students from 21 hospital- and college-sponsored programs in 18 states.


[The work of the Hessian Medical Office].

The task of this committee on quality control and radiation protection is described, along with an explanation of the legal principles used in the execution of its duties (Nuclear Safety Law and Radiological Ordinance). Furthermore, the procedures used for the evaluation of X-rays are illustrated, followed by test films of X-ray equipment and film developers. Finally, the composition and activities of the Radiation Protection Committee are described.


Task analysis provides data for MRI curriculum planning.

No standardized education or training program currently exists for magnetic resonance imaging technology. The results of this initial national task analysis will assist in development of a curriculum guide and serve as a baseline for further research.


[Quality assurance in radiology from the viewpoint of the specialists and the supervisory authorities].

Quality assurance for diagnostic imaging equipment has been successful so far. In the old Federal Republic of Germany, inspection of the existing equipment in diagnostic radiology in being completed. The estimated number of uninspected units is relatively small. All detected shortcomings have been repaired in the meantime, and very few faults have been detected in newly installed equipment. Of the status obtained following inspection and repair is to be maintained, however, more effective methods must be implemented. There is no doubt that everybody involved in quality assurance programs, including the experts and supervisory authorities, is actively working on improving the results.


TIPSS: use of metallic stents offers non-surgical alternative.

Transjugular intrahepatic portosystemic stent shunts (TIPSS) procedures can be a significant non-surgical treatment for patients with liver cirrhosis, portal hypertension and at least one episode of bleeding from gastroesophageal varices. This article presents an in-depth description of the TIPSS procedure and reports results obtained from 15 attempted TIPSS cases.


[Quality assurance from the viewpoint of the x-ray film industry].

The parameters of a film-screen-combination are listed in the directive to section 16 of the german X-ray Regulation. These parameters are determined by methods described in DIN standards and published by the manufacturer. Comparable but less precise parameters are determined in the Acceptance Test. For physical reasons it is not possible to determine the speed of an X-ray film or the intensification factor of a screen separately. The films, screens and processing chemicals delivered by the members of the manufacturer association ZVEI are kept below a deviation (expressed as relative contribution to the system speed S) of +/- 10% for the majority of products, the upper limit is +/- 15%. Poor storage and transport conditions may adversely affect the quality of X-ray films. A special labeling of the film box shall serve to guarantee safe distribution channels. The processing conditions are adjusted at the Acceptance Test according to the manufacturers recommendations. The Constancy Test of film processing serves to maintain these correct conditions. Methods deviating from the DIN-method are of limited (Bayerische method) or no value (Stuttgart method).


[Evaluation of different methods of control of film processing].

In addition to the official control method (DIN 6868), alternative test methods have been developed in the last few years: the "visuelle Methode" by Eder and the "Stuttgarter Modell." The aim of both methods is mainly to increase practicability and economy. The DIN method, however, demonstrates clear benefits, precision, practicability and economy, and it is the only method that allows a trend analysis at small intervals, which is the basis for possible preventive action.


[Sources of error in the quality assurance of x-ray equipment].

With the introduction of the German industrial protocol for quality assurance of X-ray equipment, everybody using X-ray machines fell into some sort of trap or found some of the procedures misleading. Vigorous discussions were held on every conceivable aspect of this and other protocols, and are still in progress. This paper points out some of the common traps and considers a new type dosimeter, which allows a definite separation of quality assurance of X-ray equipment and of processing and which can also be used in future for quality assurance of digital radiography equipment.


[MR tomographic aspects of olivary pseudohypertrophy].

MRI aspects of olivary pseudohypertrophy (OH) following pontocerebellar lesions of different etiology and localization are reviewed. OH is characterized by unilateral or bilateral enlargement of the inferior olivary nucleus and increased signal intensity in T2- and, especially, in proton-density (PD)-weighted images. Correlations between the extent and the uni- or bilateral presence of olivary hypertrophy and the localization of the primary pontocerebellar lesions are discussed.


[Iotrolan versus iopamidol. A controlled double-blind study with lumbar myelography].

Within the frame work of lumbar myelography, 158 patients were entered in a double-blind study in order to test a dimeric contrast medium (iotrolan) against a monomeric one (iopamidol), both of them non-ionic. A three-step scheme was applied to evaluate the X-ray pictures with respect to contrast quality. Particular attention was paid to the visibility of details, i.e. the nerve root and its course, as well as to how well it could be distinguished in the nerve root sheath. On the basis of a high level of significance (P less than 0.05), comparison of the two contrast media showed no difference in contrast quality. Sixty-nine percent of the examinations using iotrolan resulted in excellent contrast quality, whereas the corresponding very good results using iopamidol lay at 76%. Twenty-nine percent of the patients examined with iotrolan and 27% of those examined with iopamidol showed side effects. Headache occurred most frequently, followed by nausea, dizziness and neck pain. Sixty percent of the patients suffering from postmyelographic reactions reported delayed headache, which occurred most often with iotrolan rather than iopamidol. As for manifestation of other postmyelographic side effects, there were no significant differences (P less than 0.05, Fischer's test) between the two groups of contrast media.


[Ganglioneuroma of the pelvis accompanying pregnancy].

Ganglioneuroma is an uncommon benign tumor of the sympathetic nervous system. In most cases it originates from the thoracic or lumbar portion of the gangliated cord or from the medulla of the suprarenal glands. It is the differentiated form of malignant neuroblastoma. The tumor often manifests itself in young adults by displacement of the surrounding structures. In the case presented the special diagnostic problems of locating the tumor in the pelvis in early pregnancy are discussed.


Gastrointestinal tract in the immunocompromised host: opportunistic infections and other complications.

In the decade since the early 1980s, the increasing use of immunosuppressive therapy for cancer and autoimmune disease, as well as for organ transplantation, has combined with the acquired immunodeficiency syndrome epidemic to increase greatly the incidence of opportunistic infections and other complications of the gastrointestinal tract. Consequently, barium fluoroscopic and cross-sectional imaging studies tailored to address these problems are no longer uncommon. Although overlap exists, there are radiographic patterns that can direct the diagnosis to an opportunistic infection and sometimes to a specific pathogen. This article describes and illustrates the radiographic findings of gastrointestinal superinfection with Candida albicans, cytomegalovirus, Cryptosporidium spp, herpes simplex virus, Mycobacterium tuberculosis, M avium-intracellulare, and human immunodeficiency virus. Other gastrointestinal tract complications of immunosuppression are discussed, including graft-versus-host disease following bone marrow transplantation, typhlitis, and pseudomembranous colitis.


Benign adrenocortical masses: diagnosis with chemical shift MR imaging.

Benign adrenocortical masses often contain lipid; metastases and pheochromocytomas do not. Standard and lipid-sensitive (chemical shift) magnetic resonance (MR) images of the adrenal glands in 31 patients with 45 adrenal masses were reviewed to determine if simple visual analysis of these images would increase diagnostic specificity. Lipid was considered present if signal intensity of the adrenal mass relative to other tissues decreased on chemical shift images relative to comparable standard images. Both myelolipomas and 26 of 27 benign cortical masses displayed a loss of signal intensity on at least one chemical shift image; all 12 metastases, the three hemorrhages, and a cyst did not. Opposed-phase images were slightly more sensitive than fat-suppressed images in depicting lipid within benign cortical masses. All masses had higher signal intensity than that of the liver on standard T2-weighted MR images. Chemical shift MR imaging can demonstrate lipid within benign adrenocortical masses and thus increase specificity, potentially obviating biopsy and aggressive follow-up.


Male infertility: role of transrectal US in diagnosis and management.

Ultrasound (US) has become crucial in the assessment of infertility of couples, in 50% of whom the male partner is responsible. Male infertility is caused by many diverse conditions, from reparable obstructive disorders to noncorrectable intrinsic testicular failure. During the past 4 years, a select group of 70 young infertile men with azoospermia or oligospermia and low ejaculate volume were examined with transrectal US. Twenty-six patients had congenital bilateral absence of the vas deferens, 11 had congenital unilateral absence of the vas deferens and contralateral obstructive pathology, 15 had additional abnormalities thought to be directly related to semen deficiencies, and 18 patients with other causes for semen deficiency and infertility had findings that were either normal or showed minor abnormalities. The delineation of congenital and obstructive abnormalities of the distal urogenital tract with transrectal US enables an accurate diagnosis of certain cases of male infertility and helps guide appropriate clinical and surgical management.


Transrectal US in evaluation of patients after radical prostatectomy. Part I. Normal postoperative anatomy.

The appearance of the prostatic fossa on transrectal ultrasound (TRUS) scans obtained after radical retropubic prostatectomy (RRP) was studied in 25 patients believed to have no tumor on the basis of their level of serum prostate-specific antigen (PSA) (< or = 0.4 ng/mL). The profile of the vesicourethral anastomosis (VUA) in the midsagittal plane was tapered in 13 patients (52%) and nontapered in 12 patients (48%). The nontapered profile was associated with incontinence in nine of 11 patients (82%) followed up for less than 12 months but in only four of 14 patients (28%) followed up beyond 1 year. In 20 patients (80%), a hypoechoic soft-tissue lesion (average volume, 1.7 cm3) was seen anterior to the VUA and indented the anterior bladder wall. The length of the urethral high-pressure zone increased with muscular contraction of the pelvic floor. Knowledge of the baseline anatomic structures depicted on TRUS scans obtained after RRP may be useful in selection of tissue for TRUS-guided needle biopsy in patients with elevated levels of PSA. The many post-surgical changes reduced the specificity of the TRUS findings.


Seminal vesicles: biopsy-related hemorrhage simulating tumor invasion at endorectal MR imaging.

The diagnosis of seminal vesicle invasion by prostatic carcinoma is based on observation of foci of relatively decreased signal intensity on T2-weighted magnetic resonance (MR) images. Similar findings were observed in the absence of tumor invasion in nine patients who had recently undergone prostatic needle biopsy. Noncorresponding foci of abnormally increased signal intensity were also present on T1-weighted images in eight patients. These signal intensity abnormalities were of variable location and extent, and usually did not follow the expected pattern of spread from the primary prostatic tumor site. Radical prostatectomy in all patients showed the seminal vesicles to be normal. Signal intensity patterns observed on MR images appear to represent hemorrhagic breakdown products related to prostatic needle biopsy, which may result in direct trauma to the seminal vesicles. Another potential mechanism is retrograde transport of blood products from the site of prostatic biopsy to the seminal vesicles via the ejaculatory ducts. Awareness of this phenomenon will assist in accurate interpretation of MR images for staging of prostate cancer.


Transvaginal US-guided aspiration of ovarian cysts and solid pelvic masses.

Sixty-eight transvaginal ultrasound (US)-guided aspirations or biopsies were performed in 61 patients, of whom 48 had ovarian cysts and 13 had solid pelvic masses. In one patient with an ovarian cyst, aspiration revealed malignancy. Thirty-six of the 48 cysts were drained transvaginally in 23 premenopausal and 13 postmenopausal women, with recurrence rates of 48% and 80%, respectively. In seven cases a cyst was aspirated twice. In the 13 patients with solid pelvic lesions, 11 lesions proved to be malignant, with positive biopsy results in nine (sensitivity, 82%). Two benign lesions were correctly identified. No major complication was observed. The authors conclude that the transvaginal route offers simple access to pelvic lesions in pre- and postmenopausal patients. For women with a solid pelvic lesion, transvaginal aspiration biopsy with endovaginal US guidance is a safe and effective alternative to surgery, especially for patients with previously diagnosed malignant disease.


Central pulmonary thromboembolism: diagnosis with spiral volumetric CT with the single-breath-hold technique--comparison with pulmonary angiography.

Forty-two patients were prospectively evaluated with spiral volumetric computed tomography (CT) and selective pulmonary angiography of each lung to detect central pulmonary thromboembolism. Spiral volumetric CT images obtained with either 90 mL of 30% contrast material or 120 mL of 12% contrast material were graded as excellent or good in 98% of the examinations (41 patients). Diagnosis of pulmonary embolism with spiral volumetric CT was based on the direct visualization of intraluminal clots: partial filling defects (n = 41; 37%), complete filling defects (n = 51; 46%), "railway track" signs (n = 6; 5%), and mural defects (n = 14; 12%). All 23 patients with normal findings of spiral volumetric CT had normal findings of pulmonary angiography. With spiral volumetric CT, the finding of 112 central emboli (eight main, 28 lobar, and 76 segmental) corresponded exactly to the angiographic findings, but nine intersegmental lymph nodes were erroneously interpreted as filling defects. In one case of normal pulmonary angiographic findings, asymmetry in pulmonary arterial perfusion was misinterpreted as pulmonary embolism with spiral volumetric CT. Spiral volumetric CT can reliably depict thromboemboli in second- to fourth-division pulmonary vessels.


Intersegmental (intersublobar) septum of the lower lobe in relation to the pulmonary ligament: anatomic, histologic, and CT correlations.

A thin horizontal linear area of hyperattenuation that extends laterally from the mediastinal surface of the lung within the area between the inferior pulmonary vein and the diaphragm is a common observation on computed tomographic (CT) scans of the chest. To determine the anatomic basis for this structure, the authors examined four normal human lungs (two right and two left lungs) fixed in an inflated state at pathologic and histologic examination and at CT. The structure in question was identified in one right and two left lungs. The linear area of hyperattenuation seen at CT is a septum of thin, loose intraparenchymal connective tissue that is bounded medially by the base of the pulmonary ligament, where the two sleeves of the visceral pleura appose one another, and laterally by a vertically oriented vein. The septum was identified in 39 of 50 (78%) normal chest CT scans. The pulmonary ligament often appeared to look like a beak at the mediastinal side of the lung. The septum, when visible (n = 39), was bounded medially by the beak in 28 CT scans (72%) and laterally by a vein in 24 scans (62%).


Omental flap in lung transplantation.

Some surgeons performing lung transplantation will wrap the bronchial anastomosis with omentum in an attempt to improve healing. The authors retrospectively reviewed the chest radiographs and computed tomographic (CT) scans of 31 patients who underwent lung transplantation with bronchial omentopexy to determine the CT appearance of the intrathoracic omentum and the frequency and type of chest radiographic manifestations created by the omental flap. The omental flap was seen at CT in all patients, was predominantly of fatlike attenuation, and contained linear areas of increased attenuation representing omental vessels. In 16 patients (52%), a total of 29 chest radiographic findings that corresponded to the omental flap were seen. There was no statistically significant correlation between the type of operative procedure and the presence of a chest radiographic correlate for the omentum. The results showed that the omental flap is a potential diagnostic pitfall on post-lung transplantation chest radiographs; when there is confusion, however, the omentum can be identified with CT because of its attenuation value and characteristic course.


Silicone breast implants in vivo: MR imaging.

This study was designed to evaluate pulse sequences and patient positioning for MR imaging of silicone breast implants in patients. One hundred forty-three patients (281 silicone implants) underwent imaging over a 21-month period. The combination of a T2-weighted fast spin echo technique (SE), T2-weighted fast SE with water suppression, and T1-weighted SE with fat suppression is recommended to reliably differentiate silicone from other breast tissues and to identify intracapsular and extracapsular ruptures or leaks. Seventy of the 143 patients underwent removal of their silicone implants. The sensitivity for detection of silicone implant rupture was 76%, with a specificity of 97%. Positioning the patient prone improved image quality.


Nonpalpable breast microcalcifications: frequency, management, and results of incisional biopsy.

In a series of 500 consecutive needle localizations, there were 165 biopsies for benign microcalcifications without a mass. An incisional biopsy was performed in 49 of these cases (30%). Follow-up mammograms were available for review in 39 of the cases. The average length of follow-up was 32 months. In no case did malignancy develop at the biopsy site. When an incisional biopsy is performed, careful follow-up mammography is an alternative to a repeated needle localization and biopsy in selected cases.


Schistosomiasis involving the breast.

A case of ectopic granulomatous schistosomiasis involving the breast is reported. Although schistosomiasis can involve almost any organ, involvement of the breast is very rare; to the authors' knowledge, there have been only three previously reported cases of breast involvement in the literature. This case was discovered at routine screening mammography. Innumerable, segmentally distributed, fine calcifications and mild architectural distortion were seen at mammography, and a biopsy was performed to exclude malignancy. There appears to be no way to accurately discriminate this disease from breast cancer before biopsy.


Radiation therapy of cancer in prosthetically augmented or reconstructed breasts.

The authors review the literature and report their experience with radiation treatment of 39 prosthetically augmented or reconstructed breasts in 37 patients with primary or recurrent breast cancer. Group 1 consisted of 10 patients (12 primary breast cancers), of whom six had undergone previous breast augmentation and were later treated with lumpectomy and radiation therapy. Four patients were treated with mastectomy, reconstruction, and postoperative irradiation. Local tumor control was achieved in all patients. Excellent or good cosmetic results were achieved in all but two patients. Group 2 consisted of 27 patients with recurrent breast cancer after mastectomy and reconstruction. Local tumor control was achieved in 78% (21 of 27), with a mean duration of 34 months. Excellent or good cosmetic results were achieved in 93% (25 of 27). Patients who develop primary or recurrent breast cancer in prosthetically augmented or reconstructed breasts can be offered radical radiation therapy, with satisfactory tumor control and aesthetic results.


Coronary artery calcification detected with ultrafast CT as an indication of coronary artery disease.

To assess the relationship of coronary artery calcification to angiographically detectable disease, the authors evaluated 100 patients less than 60 years of age who underwent clinically indicated coronary angiography and ultrafast computed tomography (CT). The ultrafast CT technique consisted of 3-mm-thick contiguous sections and a 100-msec acquisition time. All patients with clinically significant disease at angiography (defined as at least one stenosis with a diameter narrowing of at least 50%) had some coronary artery calcification present at ultrafast CT (100% sensitivity in this population). The absence of calcification at ultrafast CT had a 100% negative predictive value for clinically significant coronary artery disease. Specificity and positive predictive value were 47% and 62%, respectively. Sensitivity and specificity of ultrafast CT in the detection of patients with angiographically detectable disease were 94% and 72%, respectively. Ultrafast CT of the heart is an anatomically based, noninvasive test with high sensitivity for the detection of coronary artery calcification. Ultrafast CT may be beneficial in the screening of selected populations for the presence of atherosclerotic coronary disease.


MR imaging of hypertrophic cardiomyopathy.

To assess the capability of magnetic resonance (MR) imaging to define the presence, distribution, and severity of the hypertrophic process, MR imaging was performed in 20 patients with hypertrophic cardiomyopathy and in five healthy volunteers. Among the 20 patients, 13 were classified as having asymmetric septal hypertrophy and seven as having apical hypertrophy. The mean myocardial thickness in the four-chamber view obtained in end diastole in asymmetric septal hypertrophy was 23.5 mm +/- 6.8 (mean +/- standard deviation) in the basal septum; the ratio of septal to posterolateral wall thickness was 2.05 +/- 0.44 (P < .05); those values were 10.4 mm +/- 2.7 and 1.01 +/- 0.19, respectively, in five healthy volunteers. The mean myocardial thickness in apical hypertrophy was 25.3 mm +/- 4.1 in the apex, and the ratio was 2.21 +/- 0.51 (P < .05); these values were 9.6 mm +/- 1.5 and 0.95 +/- 0.17, respectively, in five healthy volunteers. Three different subtypes of hypertrophic cardiomyopathy - resting obstructive (n = 5), latent obstructive (n = 3), and nonobstructive (n = 5) - were classified according to findings at catheterization in the 13 patients with asymmetric septal hypertrophy.


Gastrointestinal hemorrhage in AIDS: arteriographic diagnosis and transcatheter treatment.

The usefulness of arteriography and transcatheter treatment was studied in nine patients with gastrointestinal hemorrhage and acquired immunodeficiency syndrome (AIDS). Selective arteriography was performed in all patients; transcatheter treatment was performed by means of embolotherapy or selective vasopressin infusion. Medical records were reviewed to determine the cause of hemorrhage and clinical outcome. Arteriography enabled identification of the site of hemorrhage in seven patients. Hemorrhage was caused by Kaposi sarcoma (n = 2), cytomegalovirus colitis (n = 1), lymphoma (n = 2), or unknown causes (n = 4). Neovascularity and dense parenchymal stain were present in patients with Kaposi sarcoma. Transcatheter treatment consisted of embolization (n = 3), vasopressin infusion (n = 2), or both (n = 1). Hemorrhage was controlled in six cases in which transcatheter treatment was administered. Complications included thrombosis of the femoral artery in a 7-month-old infant and formation of a pseudoaneurysm of the femoral artery, which was treated successfully with ultrasound-guided compression. In patients with AIDS and profuse gastrointestinal hemorrhage, arteriography often enables identification of a specific site of hemorrhage, which can be stopped with transcatheter treatment.


Nitrogen-filled liposomes as a vascular US contrast agent: preliminary evaluation.

Liposomes with a mean diameter of 1-2 microns were made to entrap nitrogen gas and tested as an ultrasound (US) contrast agent. The gas-filled liposomes, or Aerosomes (ImaRx Pharmaceutical, Tucson) were tested in vitro for size, stability, reflectivity, and acoustic characterization, and were tested in vivo for acute toxicity in mice and for cardiac imaging in rabbits after intravenous injection. Aerosomes have much greater reflectivity and higher attenuation than do standard liposomes and retain their acoustic properties after storage in aqueous media for several months. The interpolated median lethal dose of Aerosomes is approximately 2.5 mmol of lipid per kilogram, and the imaging dose is under 5 mumol of lipid per kilogram, yielding a potential therapeutic index of over 500 to 1. Postcontrast US images showed sustained enhancement of all four cardiac chambers as well as enhancement in the aorta, vena cava, and hepatic veins. Aerosomes hold promise as a contrast agent for cardiac and blood-pool imaging. Further work is in progress to characterize and develop this novel US contrast agent.


Malignant biliary obstruction: histologic findings after treatment with self-expandable stents.

Histologic analysis was performed of bile duct tissue from 15 patients who underwent treatment for malignant obstructive jaundice with a self-expandable stent. Stents were in place from 5 days to 21 months. Malignancies included adenocarcinoma of the pancreas or gallbladder or cholangiocellular, hepatocellular, or gastric carcinoma. Stents were blocked by sludge in two cases and tumor overgrowth in two others. Microscopic evaluation showed that stent placement caused complete denudation of the mucosa and mild submucosal inflammation with edema. In all but one patient, the stent was incorporated into the bile duct wall and was covered by a fibrogranulomatous tissue layer after 2 months. In some cases, an epithelium-like cell formation covered the inner surface of the stent. Tumor ingrowth was observed in two patients with poorly differentiated tumors. In stents placed for longer than 2 months, mild to moderate fibrosis and foreign body reaction were observed. Hyperplastic biliary epithelium was not found within the stent or at the stent ends.


Pancreatic duct obstruction treated with percutaneous antegrade insertion of a metal stent: report of two cases.

Expanding metal stents were used to treat symptomatic pancreatic duct obstruction in two patients with chronic pancreatitis. Both patients initially underwent percutaneous external pancreatic duct drainage and then had metal stents inserted for internal drainage. Both patients remained asymptomatic, and the stents were patent during short-term follow-up periods of 6 and 9 months, respectively. Percutaneous insertion of metal stents, which can be performed to treat pancreatic duct obstruction after a trial of external drainage has been shown to relieve the patient's symptoms, should be considered as an alternative to endoscopic stent placement or surgical drainage.


Spiral CT: decreased spatial resolution in vivo due to broadening of section-sensitivity profile.

Comparable conventional and spiral computed tomographic (CT) scanning protocols for transaxial (n = 30) and multiplanar reformation (MPR) (n = 15) imaging were performed to image the adrenal gland and the upper pole of the right kidney in the same patient, without use of intravenously administered contrast media. The sharpness of soft-tissue-fat interfaces oriented in the transverse (xy) and longitudinal (z) directions was measured as the maximum and full width at half maximum (FWHM) of the edge attenuation profile first derivative. Edge sharpness was qualitatively assessed by three blinded reviewers, who used a four-point scale. In vivo transaxial CT studies showed that the conventional scans produced slightly sharper edges than the spiral scans (mean difference of spiral and conventional FWHM = 0.30 mm [P < .05] [in z direction] and 0.21 mm [P < .05] [in xy direction]). In vivo MPR studies showed that interfaces in the xy plane were significantly less sharp with spiral scanning, whereas interfaces in the z direction were equivalent for conventional and spiral scanning (mean difference of spiral and conventional FWHM = 0.03 mm [P > .05] [in z direction] and 1.19 mm [P < .05] [in xy direction]). Significant respiratory misregistration was present on seven of 15 (47%) conventional MPR scans and on no spiral MPR scans.


Increasing contrast when viewing radiographic images.

Illuminating a developed photographic film with parallel or nearly parallel light provides increased contrast compared with the contrast obtained with diffuse incident light. The viewer of radiographic images can obtain increased contrast simply by increasing the distance between the view box and the radiograph, since this results in more parallel incident light. The authors found a contrast increase of more than 40% when x-ray film was positioned 4 m from a view box. Tilting the film relative to the surface plane of the view box gave additional contrast increase at the cost of somewhat distorted geometry. The photographic effects involved deserve a more thorough discussion in textbooks of radiologic and radiographic physics.


Spleen: dynamic enhancement patterns on gradient-echo MR images enhanced with gadopentetate dimeglumine.

To examine the pattern of immediate enhancement with gadopentetate dimeglumine on dynamic magnetic resonance (MR) images of the spleen, this study was divided into two parts: In the first part, the authors retrospectively reviewed the dynamic MR images obtained with a fast low-angle shot (FLASH) sequence in the abdomen immediately after injection of gadopentetate dimeglumine in 137 patients. In the second part, dynamic gadolinium-enhanced FLASH images were prospectively compared with contrast material-enhanced computed tomographic (CT) scans in 17 patients with focal splenic lesions discovered on CT scans. In the first part, 108 patients (79%) had an arciform pattern of contrast enhancement; 22 patients (16%), a uniform pattern of high signal intensity; and seven patients (5%), a uniform pattern of low signal intensity. Most patients had arciform enhancement of the spleen; uniform enhancement occurred in some patients with underlying malignant or inflammatory disease. In the second part, all focal lesions seen on CT scans were seen on dynamic MR images (75 lesions), significantly more than were seen on FLASH images (15 lesions) (P < .001).


Gastroesophageal reflux disease: correlation of esophageal pH testing and radiographic findings.

In an attempt to ascertain radiologic efficacy in patients with evidence of gastroesophageal reflux disease (GERD) at pH testing, radiographic findings were correlated with pH values obtained with an esophageal monitor worn for a 24-hour period in 112 patients. Fifteen (30%) of 50 patients with abnormal pH test results had esophagitis diagnosed radiographically, compared with six (10%) of 62 with normal pH test results (P < .05). The severity of abnormal pH monitoring results was classified but did not correlate significantly with the prevalence of esophagitis diagnosed radiographically. Hiatal hernia was also more common (80% vs 60%) in patients with abnormal pH test results (40 of 50 patients) than in those with normal results (37 of 62 patients) (P < .05). Pharyngeal, laryngeal, and pulmonary symptoms were common indications for evaluation, and 14 of 27 (52%) patients with hoarseness had an abnormal pH tracing. Only a minority of patients with evidence of GERD as defined by abnormal pH test results had reflux esophagitis diagnosed radiographically.


Esophageal motor disorders: videofluoroscopic and manometric evaluation--prospective study in 88 symptomatic patients.

Esophageal motor disorders are best evaluated with manometry, which, however, is time-consuming and not generally available. The authors prospectively investigated the yield of videofluoroscopy in detection of esophageal motor disorders in comparison with that of manometry. Eighty-eight patients with dysphagia, globus sensation, noncardiac chest pain, or progressive systemic sclerosis underwent both manometry and videofluoroscopy at 0-32-day intervals. Videofluoroscopy was performed with one swallowing study in the upright position and up to three swallowing studies in the prone oblique position. Manometric diagnoses of achalasia (n = 15), diffuse esophageal spasm (n = 1), nonspecific esophageal motor disorders (n = 44), and adynamic esophagus (n = 9) were made. Videofluoroscopically, 87% of the patients with achalasia, the one patient with diffuse spasms, 73% of the patients with nonspecific esophageal motor disorders, and all of the patients with adynamic esophagus received a correct diagnosis, for an overall sensitivity of 80%. The radiographic specificity was 79%. The authors conclude that videofluoroscopy is a valuable and reasonably sensitive technique for screening for esophageal motor disorders.