Showing papers by "Virginia Commonwealth University published in 1979"

Sensitivity of the retina to radiation damage as a function of wavelength

Abstract: —Exposure of the retina of the rhesus monkey to visible and infrared radiation from CW optical sources like the Sun, xenon lamps, etc. produces small lesions or scotomata which may be classified as thermal or photochemical, depending on the wavelength and duration of exposure. The action spectrum for the production of retinal lesions has been determined for eight monochromatic laser wavelengths extending from 1064 to 441 nm. The corneal power required to produce a lesion decreases by three orders of magnitude in going from 1064 to 441 nm. Exposure to 1064 nm radiation for 1000 s produces a typical thermal lesion at elevated retinal temperatures. whereas a 1000 s exposure to 441 nm light produces a photochemical lesion at power levels too low to raise the retinal temperature by an appreciable amount (<0.1°). The two types of lesion have entirely different characteristics as will be discussed in some detail. The photopathology of thc photochemical lesion has been studied at postexposure times ranging from 1 h to 90 days and will be demonstrated in a number of histological slides. Moreover, this photopathology correlates well with monocular visual acuity tests in the rhesus monkey as defined by the Landolt ring technique. To further elucidate the differential effects on the retina of short vs long wavelength CW radiation, we have divided a simulated solar spectrum at sea level into two spectral bands. 400–800 nm and 700–1400 nm, and determined the radiant exposures required to produce very mild lcsions on the rhesus retina for exposure times of 1, 10, 100 and 1000 s. To correlate our data with solar retinitis and eclipse blindness the image diameter or spot size on the retina was 159 μm, corresponding to the image size of the Sun on the human retina. Exposure to the 400–800 nm spectrum for durations of 10 s or greater required approximately 400 J/cm2 to produce a mild photochemical lesion. Reciprocity is maintained over the exposure range 10–1000 s. Radiant exposure to the 700–1400 nm spectrum, on the other hand, required roughly 69,100 J/cm2 for a 1000 s exposure. This was a mild thermal lesion. We were unable to produce a lesion for exposure times less than 1000 s. We interpret these data to mean that solar retinitis and eclipse blindness are primarily photochemical events produced by the short wavelength component of the solar spectrum, and that the infrared component of the solar spectrum plays only a minor role in these retinal pathologies.

The genesis and significance of delayed traumatic intracerebral hematoma.

Abstract: During a 34-month period, 12 cases of delayed traumatic intracerebral hematoma (DTICH) were diagnosed among 162 consecutive prospectively studied patients admitted to the Medical College of Virginia with severe closed head injuries. All patients were unresponsive to command and unable to utter formed words at the time of admission. The interval from injury to diagnosis of DTICH by computerized tomography (CT) was within 48 hours in 11 of the 12 cases. Six patients had no decompressive surgery before the development of the lesion. Four patients had undergone decompressive surgery and then developed DTICH on the contralateral side. Two patients developed lesions in the vicinity of the operative site that were thought not to be the result of operation. The development of DTICH was not heralded by neurological deterioration nor by elevation of intracranial pressure. Eleven of the 12 patients had suffered a secondary hypoxic insult soon after the head injury. We suggest that the CT appearance of DTICH is likely to represent hemorrhage into an existing traumatized area and is an epiphenomenon rather than a cause of severe primary and secondary brain damage.

Characteristics of transport of 4-amino antifolates and folate compounds by two lines of l5178y lymphoblasts, one with impaired transport of methotrexate.

Abstract: In a line of L5178Y lymphoblasts resistant to methotrexate (MTX) by virtue of a permeability defect, there is a marked decrease in the membrane transport of MTX, aminopterin, and 5-methyltetrahydrofolate. Influx is depressed by 93, 92, and 96%, respectively, as compared to MTX-sensitive cells when the extracellular levels are 1 µm. This is compatible with a common defect in a high-affinity transport carrier mechanism shared by these three folate compounds. Conversely, however, adsorption of MTX to the surface of resistant cells is slightly increased. Uptake of 3H following exposure of these cells to [3H]folic acid is comparable in both resistant and sensitive lines, supporting the concept that influx of folic acid is mediated largely by a process independent of the MTX-tetrahydrofolate cofactor carrier. In addition to the quantitative differences in the rates of transport of 4-amino antifolates and 5-methyltetrahydrofolate, there are important differences in the characteristics of transport of these substances in these two cell lines. The Q 27–37°'s for MTX influx in MTX-sensitive and -resistant cells are 6.4 and 1.4, respectively. While influx is markedly inhibited by p -chloromercuriphenylsulfonic acid and 5-formyltetrahydrofolate in MTX-sensitive cells, only a small component of influx in resistant cells (∼25%) is inhibited by these agents. Transstimulation of MTX influx can be demonstrated in both cell lines but to a much lesser extent in resistant L5178Y cells. Sodium azide stimulates MTX influx in sensitive cells but has no effect on influx in resistant cells. However, this metabolic poison augments net uptake of MTX in both cell lines. Net accumulation of exchangeable MTX is markedly reduced in resistant cells, but differences in influx and net transport between resistant and sensitive cells decrease as extracellular MTX is increased, indicating the utility of high extracellular MTX levels in generating free intracellular drug as an approach to overcoming the permeability defect. These data suggest that the bulk of transport of antifolates and 5-methyltetrahydrofolate in resistant cells occurs by a process distinct from the MTX-tetrahydrofolate cofactor carrier system. The MTX-tetrahydrofolate cofactor transport carriers in MTX-resistant cells have undergone a marked reduction in affinity for their substrate, or else the major portion of these carriers have been deleted or are not operational. The observation that azide enhances net MTX uptake in resistant as well as sensitive L5178Y cells along with findings in other studies that the net uptake of folic acid is enhanced by azide raises the possibility that the effects of metabolic inhibitors on net transport of MTX and folic acid may be mediated, at least in part, by inhibition of a common exit process.

Enterobacter cloacae septicemia in a burn center: epidemiology and control of an outbreak.

Abstract: An outbreak of infections due to Enterobacter cloacae occurred in the burn center at the Medical College of Virginia (Richmond, Virginia) in 1976. Fifteen patients had bacteremia due to E. cloacae; 10 cases of bacteremia occurred during a six-week period in January and February. The development of bacteremia was significantly related to the extent of third-degree burn and to admission to the burn center in January and February but not to the presence of an intravenous cannula, underlying disease, or antimicrobial therapy. E. cloacae was spread by contaminated hands of personnel and by cross-contamination of hydrotherapy water. A shortage of staff appeared to be an important factor in the occurrence of the outbreak. Control measures included an increase in the number of personnel, instruction of personnel in proper aseptic technique, and adoption of a new hydrotherapy protocol.

An Interpersonal Communication Analysis of Relationship in Psychotherapy

Abstract: In psychotherapy theorty, research, and practice, relationship has remained a controversial and elusive construct. Psychoanalytic theorists highlight transference-countertransference factors as central theoretical and technical components, but have yet to translate these constructs into a scientifically useful format. Rogerian theorists have consistently specified the relationship factors of positive regard, empathy, and congruence as "necessary and sufficient conditions" for constructive personality change in therapy and have evolved operational anchorings (e.g. Rogers, Gendlin, Kiesler, and Truax, 1967). Behaviorists (e.g., Wilson and Evans, 1978) conceptualize relationship factors as nonspecific variables which are important in enhancing the social influence and eliciting power of the therapist as an agent of change, while considering most client emotional responses toward the therapist as random factors which are generally irrelevant to the therapeutic process. My purpose in this paper is to offer a conceptual and empirical analysis of relationship in human behavior and in psychotherapy from an interpersonal communication perspective.

Fine structural differentiation of germ layers in the mouse at the time of mesoderm formation.

Abstract: The morphology of early postimplantation mouse egg cylinders was studied using light and electron microscopy. Implantation sites at seven, seven and one-half and eight days of gestation were dissected from the myometrium and whole implants, including both decidua and egg cylinders were processed for electron microscopy. Pre-primitive streak egg cylinders were composed of two germ layers, a tall columnar ectoderm and an outer visceral endodermal layer. Ectodermal cells demonstrated large oval nuclei and an organelle sparse cytoplasm except for many free polyribosomes. The visceral endodermal layer was composed of two cell populations. One visceral endodermal cell type observed was tall columnar in shape and appeared absorptive as demonstrated by many microvilli, pinocytotic profiles and lysosomal granules. This population was confined to extraembryonic regions of the egg cylinder. The second visceral endodermal cell type, squamous in shape, evidenced only a few microvilli, pinocytotic profiles and lysosomal granules. This population was confined to the embryonic region of the egg cylinder. Concurrent with the formation of the primitive streak an increased number of cellular junctions and nuclear pores became evident in the ectoderm. Mesodermal cells were large and stellate-shaped exhibiting many filapodia which made contact with adjacent mesodermal elements. Later the cephalic region of the primitive streak proliferated resulting in the migration of wedge-shaped mass of cells, the head process. At the most ventral extremity of the post-primitive streak egg cylinder the cells of the head process became intimately associated with the ectoderm by areas of focal contact and gap junctions.

Formation of Methotrexate Polyglutamates in Rat Hepatocytes

Abstract: Polyglutamate derivatives of [3H]methotrexate (MTX) were detected in freshly isolated rat hepatocytes in suspension within 15 min after exposure to the folate analog. The rate of polyglutamate synthesis remained constant for at least one hr, and the polyglutamate derivatives accounted for an increasing proportion of the intracellular radiolabel with time. After initial exposure to 1 µm [3H]MTX, polyglutamate derivatives of MTX continued to be synthesized even after the extracellular [3H]MTX concentration had been reduced 20-fold. Prolonged exposure of hepatocytes in primary culture to 1 µm [3H]MTX resulted in the formation of longer-chain polyglutamate derivatives of MTX. The present studies demonstrate another important biosynthetic capacity of the freshly isolated hepatocyte and suggest the usefulness of this system for studying the mechanism of, and controlling factors in, the synthesis of polyglutamate derivatives of MTX. The ramifications of the formation of MTX polyglutamates on drug cytotoxicity in general and hepatotoxicity in particular are considered.

Early Diagnosis of Relapse in Acute Myeloblastic Leukemia — Serologic Detection of Leukemia-Associated Antigens in Human Marrow

Abstract: We tested serial bone-marrow samples from 47 adults with acute myeloblastic leukemia in remission for reactivity with heteroantiserums to leukemia-associated antigens, to determine whether imminent relapse could be detected in patients with acute leukemia. Of 26 patients who relapsed by standard morphologic criteria, 21 had increased immunoreactivity of bone marrow for one to six months (mean, 3.7 months) before relapse. High concordance was observed between a positive test and relapse during the period of study (chi-square = 27.53, P<0.001). The median time to relapse after a positive test was four months, as compared with the median remission duration of 19 months for the whole group (P<0.02, Peto's log-rank analysis). Serologic detection of leukemia-associated antigens in marrow may be a reliable indicator of imminent relapse in acute myeloblastic leukemia. (N Engl J Med 301:1353–1357, 1979)

Partial t-spreads and group constructible (s,r,μ)-nets

Abstract: We give a method for constructing (s,r,μ)-nets out of partial t-spreads. As one consequence, we are able to apply a theorem of Bose and Bush to improve the known upper bound for the number of subspaces in a partial t-spread. Conversely, known existence results for partial t-spreads yield (s,r,μ)-nets with large replication number r.

The Impact Message Inventory: A New Measure of Relationship in Counseling/Psychotherapy and Other Dyads.

Abstract: The Impact Message Inventory assesses momentary emotional and other engagements of one person by another during ongoing transactions in counseling/psychotherapy and other dyads. A 259-item form of the inventory was administered to 451 undergraduates of both sexes. Fifteen groups of approximately 30 subjects each recorded their impacts to 1 of 15 paragraph descriptions of stylistically "pure" interpersonal types adapted from Lorr and McNair's Interpersonal Behavior Inventory items. Item and factor-analytic procedures, cross-validated on split samples, yielded an 82-item revised inventory of high internal consistency reliability. Results offer strong support for circumplex ordering of the inventory's 15 interpersonal subscales, whereas inconsistent support is found for the prediction that impact messages occupy a two-factor space around the axes of status and affiliation. Applications of the inventory in counseling/psychotherapy research and practice are discussed. In counseling theory and research, relationship has remained a controversial and elusive construct. What has been missing is a relevant measure tied to a systematic and comprehensive theory. This report presents the development and initial validation of an inventory designed to assess relationship behaviors in dyads, including counselor-client and husband-wife, as well as pairs of interactants in other social contexts. The Impact Message Inventory (Kiesler et al., 1975, 1976) taps the momentary affective, cognitive, and behavioral covert engagements of one person by another during ongoing face-to-face communication. The inventory shows promise for single-case and group studies of counseling practice and for counselor training and supervision. It can be used as a dependent variable measure by which the counselor, observers, and significant others in the client's life record their sequential impact responses to the client over the course of counseling and follow-up periods. In marital counseling it can serve as a repeated measure filled out by each partner on the other and also can be in

A new steroidal alkylating agent with improved activity in advanced murine leukemias.

Abstract: The homo-aza-steroidal ester of [p-[bis(2-chloroethyl)amino]phenoxy] acetic acid, 3β-hydroxy 13α-amino-13,17-seco-5α-androstan-17-oic-13,17-lactam-p-bis(2-chloroethyl)aminophenoxyacetate, gave a 100% increase in lifespan over controls in the treatment of L1210 leukemia by IP administration on a days 1 and 4 treatment schedule. This ester gave a maximum activity of 383% increased lifespan over controls in the treatment of P388 leukemia by IP administration on a daily treatment schedule. Activity in advanced L1210 (41% increased lifespan) and P388 leukemias (173% increased lifespan) was maintained, indicating that this compound is the most promising of a number of congeners tested to date.

Surgical implications of acid ingestion.

Abstract: Ingestion of mineral acid may be accidental or intentional. This form of corrosive usually sears the esophageal mucosa only to produce major injury to the stomach. The prepyloric antrum is almost always injured, but the fundus and cardia may be involved if the stomach is empty at the time of ingestion. Clinically, significant esophageal injury occurs in less than 20 per cent. Initial treatment is supportive, with early operation reserved for patients with severe ingestion in whom gastric necrosis rapidly ensues. In the more typical patient, however, late gastric outlet obstruction still makes surgical therapy mandatory. Subtotal gastrectomy with Billroth I reconstruction is usually possible and is the treatment of choice. Total parenteral nutrition is a useful adjunct.

Fracture of the coracoid process associated with subglenoid dislocation of the shoulder. A case report.

Abstract: Choosing the approach for revision total hip replacement is an essential part of surgical planning and should be done well before the patient enters the operating room. Planning includes selecting patient positioning, the location of the incision, techniques for managing previous incisions, the needed exposure equipment, and the steps needed to extend the exposure. More extensive exposure on both the acetabular and femoral sides is often required in revision surgery.

Something old, something new: attention in Wundt and modern cognitive psychology.

Abstract: The theories of attention of Wundt and various contemporary psychologists are described, compared, and related to experimental findings. It is argued that Wundt's theory is a viable alternative to contemporary formulations and that differences between the old and modern theories are based on different experimental paradigms. The historical relationship between Wundt and modern researchers is explored, showing that modern psychologists are generally ignorant of Wundt's psychology even when they adopt an approach quite compatible with it.

Gender Differences in the Career Aspirations of Recent Cohorts of High School Seniors

Abstract: The career aspirations of three cohorts of high school seniors are examined for evidence of changing patterns of sex role socialization. Several important changes occur in the distribution of male and female choices, most of which serve to reduce the overall level of gender dissimilarity. A multivariate analysis of aspirations for high status professional jobs highlights the importance of gender in the choice of career goals. The direct effects of gender are larger than those of the other independent variables (SES, class quartile, residential location and cohort), all of which interact with gender in their relationship to aspirations. In the largest of these interactions the relationship of gender to aspirations weakens across cohorts, suggesting an important change in the acceptance of occupational sex roles by high school seniors.

Fungus balls of the urinary tract

Abstract: Fungus balls of the urinary tract are rare and usually associated with infection by Candid albicans. Since 1968 five patients seen at the Medical College of Virginia Hospitals presented with this peculiar manifestation of candidiasis. Summaries of their epidemiologic clinical, pathologic, and mycologic data are presented. All Candida fungus balls involved the upper collecting system and were detected by radiography and confirmed by culture and/or pathologic section. Two of the five patients completely recovered. Three patients were treated with flucytosine and/or local irrigation with a polyene antifungal agent. Two recovered and the third died of probable bacterial sepsis. One patient was treated successfully with surgical removal of the fungus ball and a brief period of local irrigation with amphotericin B (AMB). The fifth patient recovered after 28 days of parenteral AMB. Predisposing factors and pathogenetic mechanisms are discussed, and a rational approach to therapy is outlined.

Optimizing State Patrol Manpower Allocation

Abstract: One of the most difficult tasks of state highway patrol administrators is allocation of manpower; i.e. determining the most effective level of operational manpower for patrol tasks. Typically, administrators resolve the allocation problem by relying on prior statistical data and by employing subjective analysis. In general, only limited systematic analyses have been applied to the problem. This paper presents an integer goal programming model for allocating highway patrolmen to road segments within a patrol region. The model is demonstrated via a case example of the Nebraska State Patrol. The results of the model are valuable to the patrol administrator for considering departmental goals and priority structure, in addition to available historical data, in the assignment of state patrol manpower.

Hyperfine-field distribution in Fe 3 Si 1-x Al x alloys and a theoretical interpretation

Abstract: In ${\mathrm{Fe}}_{3}{\mathrm{Si}}_{1\ensuremath{-}x}{\mathrm{Al}}_{x}$ alloys with small $x$ the Si and Al nuclear magnetic resonances are 31.5 and 16.1 MHz, respectively. The concentration dependences of the frequencies of these resonances are linear, the Si resonance shifting to lower frequencies, the Al resonance to higher frequencies. Both the magnitudes and concentration dependences of the Si and Al internal fields are in agreement with the predictions of a simple model which Jena and Geldart, following the approach of Daniel and Friedel, have found successful in calculating the fields of $\mathrm{sp}$ elements in Heusler alloys. A positive sign is predicted for the Si internal field, and a negative sign for the Al field. Magnetization and lattice-parameter data required for the comparison of experiment and theory are also reported.

A ristotle and Nonreferring Subjects

Abstract: It is a widely accepted view amongst scholars that Aristotle believed that the subject of an assertion might fail to refer. Two texts, De Interpretatione xi 21 a 25-28 and Categories x 13 b 12-35, are generally cited as evidence for this belief. In this paper I will argue that both passages have previously been misunderstood and that Aristotle did not accept the possible referential failure of the subject of an assertion. In Section I, after first discussing the standard interpretations of both texts, I note the difficulties which result from these accounts. In Section II I offer a brief general argument showing that Aristotle's own account of what an assertion is implies that it is impossible for the subject of an assertion to fail to refer. In Section III I present my own analysis of each passage and show that when properly understood neither is in any way concerned with the problem of referential failure.

Learning Style Preferences: Physical Therapy Students in the United States

Abstract: The purpose of this study was to describe the learning style preferences of students enrolled in their first year of basic professional programs in physical therapy in the United States in the academic year 1975 to 1976. The testing instrument used was the Learning Styles inventory developed by Canfield and Lafferty. A sample of 1,099 (40.8% of the total population) was collected. The results have been tabulated using descriptive statistics of means and standard deviations for: 1) total sample, 2) men, and 3) women. The "typical" or "average" physical therapy student is described. These results have important implications for physical therapy educators in terms of arranging their instructional activities to optimize learning.

Picture Preferences of Children and Young Adults.

Abstract: The authors offer definitions of six types of illustrations and report a study of student preference for those picture styles. Generally, their subjects, 380 students in grades K, 1, 2, 3, 5, 9, and 11, preferred photographs, with realistic drawings ranked second. But there were significant differences between sexes and age groups.

A multimethod assessment of personal space development in female and male, black and white children

Abstract: In order to obtain evidence of the effects of demographic parameters and measurement techniques on personal space, several different assessments were used to determine the impact of subject age, race, and sex on interpersonal distancing. Thirteen different variables representing stimulation, paper-and-pencil, and behavioral techniques indicated that as age increased, personal space requirements decreased, particularly for whites. Blacks as compared to whites required less space at age 7, and mixed-sex dyads tended to require more space than same-sex dyads. The results thus indicate that while some previous findings appear to be measurement method specific, others show intermethod consistency.

Knowledge and structures of scientific growth measurement of a cancer problem domain

Abstract: In the context of bridging the so-called externalist and cognitive perspectives on the growth of research communities, a cancer “problem domain” is examined (1) to distinguish a growth in knowledge from a proliferating research literature, and (2) show how measurement of formal communication, uninformed by the “historical record,” clarifies or distorts sociological interpretations of innovation and growth in biomedicine. Specifically, coauthorship and citation networks are analyzed for reverse transcriptase researchers, 1970–74. This analysis reveals the visibility of large National Cancer Institute laboratories in the research literature, but demonstrates the need to augment disaggregated network data with intellectual and social (policy) history to explain the growth and structure of the domain.