Showing papers by "Drexel University published in 1987"

Long‐term observations of the patterns of failure in patients with unresectable non‐oat cell carcinoma of the lung treated with definitive radiotherapy report by the radiation therapy oncology group

Abstract: This report details the patterns of tumor recurrence in two prospective randomized studies involving 551 patients with histologically proven unresectable or medically inoperable non-oat cell carcinoma of the lung treated with definitive radiotherapy. Patients were treated according to two protocols, depending on the stage of the tumor: (1) Patients with T1, 2, 3-NO, 1, 2 tumors were randomized to four different regimens: 4000 cGy split course (2000 cGy in five fractions, per 1 week, 2 weeks rest and additional 2000 cGy in five fractions, per 1 week) or 4000, 5000, or 6000 cGy continuous courses, five fractions per week. (2) Patients with T4, any N or N3, any T stage tumors were randomized to be treated with 3000 cGy tumor dose (TD), ten fractions in 2 weeks, 4000 cGy split course (described above), or 4000 cGy continuous course. In the patients with less advanced tumors (Study 1) the intrathoracic failure rate within the irradiated volume was 48% with 4000 cGy continuous, 38% with 4000 cGy split course or 5000 cGy continuous, and 27% for patients receiving 6000 cGy continuous course. The failure rate in the nonirradiated lung ranged from 25% to 30% in the various groups. Patients with adenocarcinoma or large cell undifferentiated carcinoma had better intrathoracic tumor control (35%) than those with squamous cell carcinoma (20%). The incidence of distant metastases was 75% to 80% in all histologic groups. Distant metastases appeared sooner after therapy in the patients with adenocarcinoma or large cell undifferentiated carcinoma. The initial failure rate in the brain was 7% in patients with squamous cell carcinoma, 19% with adenocarcinoma, and 13% in patients with large cell carcinoma. The ultimate incidence of brain metastases was 16% in squamous cell carcinoma, and 30% for adenocarcinoma or large cell undifferentiated carcinoma. Higher doses of irradiation will be necessary in order to improve the intrathoracic tumor control. Clinical trials by the Radiation Therapy Oncology Group, some of them involving multiple daily fractionation, are in progress. Furthermore, because of the high incidence of distant metastases, effective systemic cytotoxic agents are critically needed to improve survival of lung cancer patients. The high frequency of brain metastases suggests that, as in small cell carcinoma of the lung, elective irradiation of the brain may be necessary, if not to improve survival to enhance the quality of life of patients with adenocarcinoma and large cell carcinoma.

Clinical determinants of mortality in chronic congestive heart failure secondary to idiopathic dilated or to ischemic cardiomyopathy.

Abstract: To determine which of the many clinical parameters routinely collected influence mortality in patients with congestive heart failure (CHF), 201 patients with idiopathic or ischemic dilated cardiomyopathy were prospectively followed for a 28-month study period. Mean age of the study group was 62 ± 10 years, 60 % had Ischemic cardiomyopathy, and two-thirds were in New York Heart Association functional class If or III. Fifteen clinical variables were analyzed using a Cox proportional hazards model, while individual variables also were calculated for independent prognostic significance. There were 85 deaths, 26 (31 %) of which were sudden cardiac deaths. Three characteristics at the study entry independently predicted an increased mortality risk: left ventricular ejection fraction, maximal oxygen uptake and ischemic cardiomyopathy. A Cox proportional hazards model showed that the combination of VO2max, S3 and the diagnosis of ischemic cardiomyopathy provided the best estimates of risk for an early death. Mortality for the low-risk group was only 5 % at 6 months and 10 % at 1 year. In contrast, in patients with an S3, ischemic cardiomyopathy and low maximal oxygen uptake, 6-month mortality was 24 % and 36 % at 1 year (p < 0.001). Thus, these patients at high risk with left ventricular dysfunction associated with ischemic heart disease, a decreasing exercise tolerance and the development of an S3 should be strongly considered for an interventional trial with the aim of decreasing mortality.

Target Abnormal Returns Associated with Acquisition Announcements:Payment, Acquisition Form, and Managerial Resistance

Abstract: Abnormal returns earned by target firms at the time of initial acquisition announcements are related to form of payment, degree of resistance, and type of offer. Results indicate that interdependence among these characteristics is important. Previous research suggests that tender offer targets earn higher abnormal returns than merger targets. After controlling for payment method and degree of resistance, however, the difference in abnormal returns between tender offers and mergers is insignificant. Resisted offers are associated with insignificantly higher returns than unresisted offers. Abnormal returns associated with cash offers are significantly higher than those associated with stock offers.

A Work-Nonwork Interactive Perspective of Stress and Its Consequences

Abstract: This paper examines the intersection of work and non-work roles as related to stress, and proposes an integrative framework for understanding the relationships among stressors, stress, and strains in the work and nonwork domains. The sources and consequences of work-nonwork stress are delineated, and directions for future research are identified.

Comparative distribution of mRNAs for glutamic acid decarboxylase, tyrosine hydroxylase, and tachykinins in the basal ganglia: an in situ hybridization study in the rodent brain.

Abstract: Neurotransmitter-related messenger RNAs were detected by in situ hybridization in sections of rat and mouse brains by using 35S-radiolabelled RNA probes transcribed from cDNAs cloned in SP6 promoter-containing vectors. The distribution of messenger RNAs for glutamic acid decarboxylase, tachykinins (substance P and K), and tyrosine hydroxylase was examined in the striatum, pallidum, and substantia nigra. Dense clusters of silver grains were observed with the RNA probe complementary of the cellular messenger RNA for glutamic acid decarboxylase (antisense RNA) over most large neurons in the substantia nigra pars reticulata and medium-sized to large neurons in all pallidal subdivisions. A few very densely and numerous lightly labelled medium-sized neurons were present in the striatum. Among the areas examined, only the striatum contained neurons labelled with the antisense tachykinin RNA. Most of these neurons were of medium size, and a few were large. With the antisense tyrosine hydroxylase RNA, silver grains were found over neurons of the substantia nigra pars compacta and adjacent A10 and A8 dopaminergic cell groups. No signal was observed with RNAs identical to the cellular messenger RNA for glutamic acid decarboxylase or tachykinin (sense RNA). These results show a good correlation with immunohistochemical studies, suggesting that documented differences in the distribution and the level of glutamic acid decarboxylase, tyrosine hydroxylase, and substance P immunoreactivities in neurons of the basal ganglia are related to differences in the level of expression of the corresponding genes rather than to translation accessibility, stability, or transport of the gene products.

Singular-value decomposition and embedding dimension

Abstract: Data from dynamical experiments are often studied with use of results due to Shaw et al. and to Takens, which generate points in a space of relatively high dimension by embedding measurements which are typically one dimensional. A number of questions arise from this, the most obvious being how should one choose the dimension of the embedding space. In this paper we show that a method which seems promising at first sight, estimating the rank of the matrix of embedded data, is unfortunately not useful in general. Previous encouraging results have almost certainly been due to numerical problems which can, in part, be avoided by a careful application of singular-value decomposition. We show that this process does not give useful dynamical information, though it is often useful in noise control.

Ultrasound Doppler Probing of Flows Transverse with Respect to Beam Axis

Abstract: It is an accepted fact that transverse Doppler effects of the first order in v/c are nonexistent for all physical wave phenomena, including acoustics, i.e., the Doppler effect is zero for radiation normal to the direction of motion. However, this statement assumes that the incident field is a plane wave, which is not true in general for finite aperture sources. Consequently, the probing of flows transverse to the axis of finite diameter beams, particularly focused beams, is feasible. This geometry will be advantageous in many applications where the classical orientation of the sound beam, oblique to the flow, is not possible. With this motivation in mind, the theory and experimental feasibility of measuring Doppler spectra in transverse geometries is presently investigated.

Cognition and agoraphobia: Bias in the interpretation of threat.

Abstract: Foa and Kozak (1985, 1986) have proposed that agoraphobics are characterized by a fear structure in which information about physiological arousal is associated in memory with information about danger. Accordingly, agoraphobics should be more likely than normals to interpret ambiguous bodily stimuli as threatening. They are also expected to exaggerate the probability and cost of unpleasant events related to arousal more than of events unrelated to arousal. Three groups — untreated and treated agoraphobics, and normals — were administered three questionnaires designed to test these conjectures. Agoraphobics, but not normals, manifested the hypothesized cognitive biases. Moreover, these biases were greatly diminished in agoraphobics who had undergone cognitive-behavior therapy.

Decline in mitogen induced proliferation of lymphocytes with increasing age.

Abstract: We previously reported that mitogen-induced proliferative responses of lymphocytes in the elderly were significantly lower than in young individuals. To determine when this decline occurs, we evaluated the responses of 26-30 subjects of each decile from the third to the tenth decile to the T cell mitogens, phytohaemagglutinin (PHA) and concanavalin A (ConA), and the T dependent B cell mitogen, pokeweed mitogen (PWM). There was a significant decrease in the responses of the 70-, 80- and 90-year-olds to PHA and ConA (less than 40% of the 20-year-olds; P less than 0.01). The 80- and 90-year-olds also showed a decreased response to PWM (approximately 50%; P less than 0.01). The 60-year-olds showed a decreased response to all three mitogens but only the PHA and ConA responses were significantly decreased (P less than 0.01). The 50-year-olds showed a decreased response to ConA, while the 40-year-olds showed decreased responses to both PHA and ConA; both significant at P less than 0.01. The decreased response of the 40-year-olds, however, was only seen in the females. This may be due to the hormonal changes associated with menopause. The general trend of the data suggests that there is a gradual decrease in mitogen-induced proliferative responses with increasing age, large differences become apparent at the age of 60, with a further decrease in the 70s, and most importantly, they remain fairly constant thereafter. Of interest is that only three of the 111 subjects less than 60 years old failed to mount a proliferative response and in each case this was to only one mitogen, while 42 of 118 subjects greater than 60 years old did not respond to at least one mitogen. Ten of these older subjects (2/28 of the 60-year-olds) did not respond to any of the three mitogens (P less than 0.01). This lack of response may be important since we have found a significant association between the lack of response to all three mitogens and increased mortality.

Corticocortical connections within the primary somatosensory cortex of the rat.

Abstract: Corticocortical connections within the primary somatosensory (SI) cortex of rat were investigated by using discrete injections of retro- and orthogradely transported neuroanatomical tracers (including HRP, WGA, PHAL, and 3H-leucine). Tangential and vertical connections were defined with respect to the cytoarchitectonic divisions within the rat SI, specifically: (1) the “granular zones” (GZs), characterized by their dense layer IV granular aggregates, which receive the majority of direct ventroposterior (VP) thalamocortical terminations, (2) the “perigranular zones” (PGZs), the less-granular cortical matrix just surrounding the GZs, and (3) the “dysgranular zones” (DZs), the larger dysgranular regions lying centrally within and just lateral to the SI. Receptive fields recorded in the granular zones are small and discrete, whereas in the perigranular zones and especially in dysgranular zones they exhibit complex sensory convergence. A major aim of this study was to determine whether the pattern of intracortical connectivity within the SI is compatible with these observed physiological differences. In general, the perigranular and dysgranular zones contained more profuse systems of corticocortical connections than did the granular zones. For example, discrete tracer injections in the perigranular zones produced “walls” of labelling throughout the adjacent perigranular zones, while adjacent granular zones were relatively empty. Nevertheless, the granular zones were filled with dendritic branches of neurons in adjacent perigranular zones. Since these dendrites could presumably receive direct VP thalamocortical contacts, they represent one path through which this thalamic sensory information might be transmitted to the perigranular zones. Further transmission to the dysgranular zones might be subserved by a topographically organized system of reciprocal interconnections that was found between the perigranular zones and dysgranular zones. In coronal sections, labelling produced by relatively distant injections of either retro or orthograde tracers generally appeared in a columnar distribution, and was localized in perigranular zones and dysgranular zones. Within these zones, orthograde labelling consisted of vertically oriented axons emitting collateral sprays of terminals in all layers. Retrograde neuronal labelling (composed almost exclusively of pyramidal cells) was greatest in supragranular layers. Proximal to the injection site, labelling tended to spread out from these columns into supra- and infragranular layers in adjacent granular zones. The cellular basis for these connections was assessed by following single axons (filled by extracellular HRP or PHA-L injections) for long distances through thick sections. Axons of layer III pyramids travelled in a U-shaped trajectory, first ramifying locally, then descending to the deep cortical layers and ramifying further before coursing through deep cortical layers or white matter to their termination zones. It was concluded that neurons in the perigranular zones as well as the granular zones may receive VP thalamocortical information projecting to layer IV in the granular zones, and that this may be transmitted (I) to deep layers of adjacent granular zones and (3) to topographically more distant dysgranular zones. This is consistent with neurophysiological findinge that receptive fields are smallest in granular zone layer IV, and largest in layerV, and in all layers in perigranular zones and in dysgranular zones.

Method of removing contaminants from contaminated soil in situ

Abstract: A method of removing contaminants from a contaminated soil area in situ comprises the steps of placing a barrier in engagement with the exposed surface of the contaminated soil area, sealing the barrier around the periphery of the contaminated soil area and reducing the pressure beneath the outer layer of the barrier to draw the contaminants out of the soil. The barrier is comprised of an outer fluid impermeable layer and an inner fluid permeable layer. The edges of at least the outer layer of the barrier are sealed by digging a trench in the uncontaminated soil beyond the periphery of the contaminated soil area, inserting the edges of the barrier into the trench, refilling the trench and compacting the fill against the ends of the barrier. A liberating fluid may be injected into the soil beneath the contaminated soil area through a plurality of conduits inserted into the soil at acute angles.

Observation of motional-field-induced ripples in the photodetachment cross section of H-

Abstract: A ripplelike structure in the photodetachment cross section of ${\mathrm{H}}^{\mathrm{\ensuremath{-}}}$ near threshold, arising from autocorrelation in the wave function of the photoelectron in the presence of motional electric fields, is observed.

Auditory hallucinations in combat-related chronic posttraumatic stress disorder.

Abstract: Intrusive images have been reported to occur in a broad range of people with posttraumatic stress disorder, but the frequency of intrusive auditory perceptions has rarely been addressed. This study compared five posttraumatic stress disorder veterans experiencing auditory hallucinations with 31 nonhallucinating veterans on demographic, military, postmilitary, and symptom variables. Veterans who reported auditory hallucinations had higher combat exposure and more intense posttraumatic stress disorder symptoms than the other veterans. These veterans also tended to be more refractory to treatment than veterans with no hallucinations. Clinical vignettes of the veterans with auditory hallucinations are given, and the implications of the results for a subgroup of chronic posttraumatic stress disorder veterans are discussed.

Data Requirements for Reliable Estimation of Correlation Dimensions

Abstract: It is not always possible to resolve the dimension of an attractor from a finite data set. The number of data points required depends on the structure of the attractor, the distribution of points on the attractor, and the precision of the data. If the chaotic component of a system’s behaviour is sufficiently small relative to its large scale motion, and if orbits seldom visit the region of the attractor with small scale fractal structure, any method will fail to resolve the attractor’s dimension. It is simple to construct abstract mathematical examples that present this behaviour. However, while these limitations should be explicity recognised, it should also be noted that a growing body of empirical experience suggests that experimentally encountered physical and biological systems do not invariably display these behaviours. It is possible to estimate reliably the dimension of these attractors with comparatively small data sets.