Showing papers by "Virginia Commonwealth University published in 1981"

Traumatic acute subdural hematoma: major mortality reduction in comatose patients treated within four hours.

Abstract: To discover which factors contributed to recovery after surgical intracranial decompression, we reviewed the records of 82 consecutive comatose patients with traumatic acute subdural hematoma (ASDH) who were treated in a single center under a uniform protocol. The delay from injury to operation was the factor of greatest therapeutic importance. Patients who underwent surgery within the first four hours had a 30 per cent mortality rate, as compared with 90 percent in those who had surgery after four hours (P less than 0.0001). Other important prognostic variables included results of the initial neurologic examination, sex, multimodality-evoked potentials, and postoperative intracranial pressure (ICP). If all patients with traumatic ASDH were taken directly to hospitals equipped to diagnose and remove the hematoma within four hours of injury, mortality rates could be reduced considerably.

Inhibition by free radical scavengers and by cyclooxygenase inhibitors of pial arteriolar abnormalities from concussive brain injury in cats.

Abstract: We studied the role of prostaglandins and free radicals in the induction of the functional and morphological pial arteriolar abnormalities produced by concussive brain injury. Anesthetized cats equipped with a cranial window for the observation of the pial microcirculation were subjected to concussive brain injury using a fluid-percussion device following administration of cyclooxygenase inhibitors (indomethacin or AHR-5850) or the vehicle for the solution of these agents (NaCl or Na2CO3 solution). Pial arterioles from vehicle-treated animals displayed sustained dilation, reduced responsiveness to the vasoconstrictor effect of arterial hypocapnia, and a high density of endothelial lesions. Animals pretreated with cyclooxygenase inhibitors showed less pronounced vasodilation, normal responsiveness to hypocapnia, and a significantly reduced number of lesions. The vasodilation and reduced responsiveness to the vasoconstrictor effects of hypocapnia after brain injury also were inhibited by topical application of free radical scavengers (nitroblue tetrazolium, superoxide dismutase, or mannitol). The vessels from cats pretreated with free radical scavengers also had a lower density of endothelial lesions than controls. The results support the view that the immediate cause of cerebral arteriolar damage in concussive brain injury is the generation of free oxygen radicals associated with increased prostaglandin synthesis.

An iterative procedure for the estimation of the parameters of stable laws

Abstract: The sample characteristic function is used in an iterative procedure for estimating the parameters of a stable law. This method refines an earlier-developed two-step procedure which finds estimators of the characteristic exponent, a, skewness b, scale c, and location parameter 6 from non-weighted linear regressions. A number of simulation experiments with the new method show an improvement in terms of mean square error over the previous method in most cases. In particular, the improvement in estimating the parameter 3 for distributions which do not have both a close to two and 3 close to zero, and the improvement in estimating the parameters a and 6 when a is close to zero are substantial.

Mechanism of cerebral arteriolar abnormalities after acute hypertension

Abstract: Acute severe hypertension induced by intravenous norepinephrine or angiotensin in anesthetized cats equipped with a cranial window caused prolonged arteriolar vasodilation associated with reduced responsiveness to arterial hypercapnia or hypocapnia and passive response to changes in arterial blood pressure. Scanning and transmission electron microscopy of such pial arterioles showed discrete destructive endothelial lesions the density of which correlated with the degree of vasodilation. Abnormalities of the vascular smooth muscle were seen in all dilated arterioles but affected only a small number of smooth muscle cells. The oxygen consumption of pial arterioles from cats subjected to hypertension was significantly reduced in comparison to that of vessels from normal animals. The arteriolar abnormalities induced by hypertension were inhibited by pretreatment with inhibitors of cyclooxygenase (indomethacin or AHR-5850) or by topical application on the brain surface of scavengers of free oxygen radicals (mannitol or superoxide dismutase). The results suggest that the mechanism of the arteriolar abnormalities from acute hypertension involves a sudden increase in prostaglandin synthesis that leads to generation of free oxygen radicals.

Greenfield vena caval filter experience: late results in 156 patients.

Abstract: • In a review of clinical experience with the Greenfield filter in 156 patients, the most common indication for insertion was a contraindication to anticoagulation or recurrent embolism during treatment. Most of the filters (86%) were placed infrarenal, with 7% placed intentionally suprarenal and 7% misplaced but amenable to retrieval. Recurrent embolism was suspected in three patients (2%) on the basis of symptoms and was diagnosed by scan in three patients (2%). Follow-up studies on 119 local patients (11 were lost, 49 died) extended to 63 months (average, 23 months) and showed no migration or deaths due to recurrent embolism. Of 102 venacavograms obtained, occlusion of the cava was seen in only three patients (5%), for a long-term patency rate of 95%. (Arch Surg1981;116:1451-1456)

Moral Judgment The Influence of Ethical Ideology

Abstract: In order to determine when ethical ideology influences judgments of morality, individuals who endorsed an absolutist, exceptionist, subjectivist, or situationist ideology morally evaluated an actor linked, at varying levels of responsibility, to positive or negative outcomes. As predicted, absolutists judged the actor more harshly than exceptionists, but only when the described actor has foreseen or intended to produce a highly negative consequence.

Multiple Carboxylase Deficiency: Clinical and Biochemical Improvement Following Neonatal Biotin Treatment

Abstract: Multiple carboxylase deficiency is characterized by deficient activities of three biotin-dependent enzymes, propionyl coenzyme A carboxylase, pyruvate carboxylase, and beta-methylcrotonyl coenzyme A carboxylase. A newborn infant was seen with metabolic ketoacidosis, hyperammonemia, organic aciduria, seizures, and coma. Multiple carboxylase deficiency was subsequently confirmed by enzyme activity determinations in his peripheral blood leukocytes and cultured skin fibroblasts. The infant's neurologic and metabolic status improved markedly within a few days of administration of pharmacologic doses of oral biotin. His EEG, which was distinctly abnormal, became normal; his extensive computed tomography scan changes resolved, with the exception of ventricular dilation, over the next two months. After two weeks of biotin treatment the excretion of abnormal organic acid metabolites was reduced and his carboxylase activities increased to the normal range. However, the activities of these enzymes increased only to 30% to 55% of normal in fibroblasts incubated in supplemental biotin. This partial correction of enzyme activity differs from that observed in other individuals with multiple carboxylase deficiency and suggests biochemical heterogeneity in this disorder. Prompt diagnosis and intervention can avert some of the pathologic complications of this biotin-responsive condition.

A Goodness-of-fit Test based on the Empirical Characteristic Function when Parameters must be Estimated

Abstract: SUMMARY The goodness-of-fit test using the empirical characteristic function proposed by Koutrouvelis (1980) is extended to the case where parameters must be estimated. The proposed test statistic is shown to have an asymptotic chi-squared distribution with degrees of freedom reduced by the number of parameters estimated.

Genetic analysis of K88-mediated adhesion of enterotoxigenic Escherichia coli

Abstract: Four cistrons (adh) involved in the expression of the K88 adhesion system have been identified and mapped. Three of these (adh A, adh B and adh C) are located in a single operon(I) whereas the fourth (adh D) is expressed from a separate promoter (operon II). The polypeptides encoded by these cistrons have been identified and their role in the formation and regulation of K88 fimbriae (pili) is discussed.

Attributions, Affect, and Expectations: A Test of Weiner's Three-Dimensional Model

Abstract: In a test of predictions derived from Weiner's reformulated three-dimensional model of attributions, college students who had performed well or poorly on an examination reported the locus, stability, and controllability of the causes of their performance, their affective reactions, and their expectations. As is consistent with Weiner's model, more positive affective reactions were reported by students who (a) felt they controlled the causes of their performance, (b) attributed success to internal factors or failure to external factors, and (c) attributed their outcomes to factors that were stable, controllable, and internal. Expectations, however, were related more to perceived locus of cause and controllability than to stability. The implications of attributions and perceived control in educational settings are discussed in relation to learned helplessness, expectations, and reactions to failure. Weiner's approach to classroom motivation and experience (Weiner, 1972, 1979, 1980) emphasizes the importance of causal attributions in explaining the consequences of academic failure and success. According to this perspective, achievement striving, affective reactions, and expectations concerning future outcomes are determined, in part, by students' attributional conclusions concerning their classroom experiences. Following performance on an academic task, students react affectively in a generally positive or negative manner, formulate causal attributions to explain their performance, and then experience further affect and expectancy changes dependent on the nature of these attributions. Although a substantial amount of laboratory research suggests such linkages exist (Weiner, 1979), relatively few studies have examined Weiner's three-dimensional model in the context of actual academic tasks. The present study examined Weiner's proposed model of educational attributions by assessing the relationship between the attributions, affect, and expectations of college students following a course examination.

Topical clindamycin therapy for acne vulgaris. A cooperative clinical study.

Abstract: • Eleven institutions participated in an eight-week controlled clinical study to evaluate treatment of acne vulgaris with topical clindamycin hydrochloride and clindamycin phosphate. Three hundred fifty-eight patients with comparable baseline pustule, papule, and nodule counts applied 1% clindamycin hydrochloride, 1% clindamycin phosphate, or a hydroalcoholic vehicle twice daily. Every two weeks, lesions were counted, and patients' evaluations of their acne conditions were scored. By week 8, pustule and papule counts in the groups who were receiving clindamycin were significantly lower than those in the group receiving placebo. Also, more patients who were receiving clindamycin thought their acne improved by week 8 (with significantly higher change-in-acne scores) than did the patients receiving placebo. Patients receiving clindamycin reported 12 episodes of diarrhea; only one episode was considered to be treatment related. These results substantiate the clinical impession that topical clindamycin is effective treatment for acne. (Arch Dermatol1981;117:482-485)

Looking back: An analysis of reminiscence functions and triggers

Abstract: The purpose of this study was two-fold: to determine if hypothesized functions and triggers of reminiscence are empirically supported by a Reminiscence Uses Scale and Reminiscence Triggers Scale, and to determine if functions can be predicted from triggers subject variables.Ninety-one elderly residents of retirement communities completed the paper and pencil survey instrument. A factor analysis of the Reminiscence Uses Scale yielded three factor subscales: Self-Regard/Image Enhancement, Present Problem Solving, and Existential/Self-Understanding. In contrast, five factor subscales were extracted from the Reminiscence Triggers Scale: Death Awareness/Resignation, Death Awareness-Other, Realization of Goals/Accomplishments, Changes/Threats to body, and Change in Career/Life's Direction. A multiple regression analysis indicated that Self-Regard/Image Enhancement was predicted by Realization of Goals/Accomplishments and Reminiscence Frequency; Present Problem Solving was predicted by Death Awareness/Resignation; and Existential/Self-Understanding by Changes/Threats to body and Life Review. These findings support a basic distinction between inter-and intrapersonal reminiscence, suggest a relationship between contemporaneous experiences and memories, and lend empirical support to the construct validity of earlier theoretical views on reminiscence in old age.

Selective activation of 5'-deoxy-5-fluorouridine by tumor cells as a basis for an improved therapeutic index.

Abstract: The intracellular metabolism of a new fluoropyrimidine, 5′-deoxy-5-fluorouridine (5′-dFUrd), was compared with the metabolism of 5-fluorouracil (FUra), 5-fluorouridine (FUrd), and 5-fluoro-2′-deoxyuridine (FdUrd) in freshly isolated bone marrow cells and Ehrlich ascites tumor cells. Following exposure to tumor cells, all four fluoropyrimidines were metabolized to identical products ( i.e. , FUra, 5-fluorouridine 5′-monophosphate, 5-fluorouridine 5′-diphosphate, 5-fluorouridine 5′-triphosphate, and 5-fluoro-2′-deoxyuridine 5′-monophosphate), all produced an incorporation of FUra into RNA (FUrd > FUra > FdUrd > 5′-dFUrd), and all completely inhibited thymidylate synthetase activity by 1 hr. However, in bone marrow cells, very different patterns were observed. 5′-dFUrd accumulated in the cells, but there were no measurable metabolism, no incorporation of FUra into RNA, and no inhibition of thymidylate synthetase activity. In contrast, both FUra and FUrd were metabolized and produced an incorporation of FUra into RNA (2.7 pmol FUra per µg RNA and 4.8 pmol FUra per µg RNA at 2 hr, respectively) in bone marrow. Only a minor inhibition of thymidylate synthetase activity was detected. FdUrd also was metabolized by bone marrow cells, produced a low level of FUra incorporation into RNA (0.23 pmol FUra per µg RNA at 2 hr), and produced a complete inhibition of thymidylate synthetase activity. Since 5′-dFUrd is not directly cytotoxic itself, its superior therapeutic index compared to other fluoropyrimidines may largely reflect the selective activation of 5′-dFUrd by sensitive tumor cells as opposed to bone marrow cells, which can activate FUra, FUrd, and FdUrd.

Prostaglandins in physiological and in certain pathological responses of the cerebral circulation.

Abstract: The most abundant prostaglandin produced by brain tissue varies from species to species. The most abundant prostaglandin produced by brain microvessels is PGI2, PGG2, PGH2, PGI2, PGE2, PGD2, and arachidonic acid dilated cerebral arterioles. Cyclooxygenase inhibitors (indomethacin, AHR-5850), in doses that reduced prostaglandin synthesis substantially, did not affect resting vascular caliber and did not influence the responses of cerebral arterioles to arterial hypoxia, arterial hypercapnia, or arterial hypocapnia, suggesting that prostaglandins are not involved in the mediation of these responses. The vasodilator action of vasoactive intestinal peptide on cerebral arterioles was blocked by these cyclooxygenase inhibitors. The cerebral arteriolar damage induced by fluid-percussion brain injury was inhibited by pretreatment with cyclooxygenase inhibitors, or with free radical scavengers. Topical application of arachidonic acid or PGG2, reproduced the damage seen with brain injury. These findings show that prostaglandins are mediators of the cerebral arteriolar damage due to brain injury and that their mechanism of action is dependent on the generation of free oxygen radicals.

Teaching leisure skills to severely handicapped adults: An age-appropriate darts game

Abstract: This study demonstrates the acquisition and generalization of dart skills by three severely multihandicapped adults. The program took place in a community adult development center. By identifying the motor responses required to play darts, a 7-step task analysis was generated to facilitate instruction. Systematic training procedures using applied behavior analysis were implemented. A combination multiple baseline across subjects and changing criterion design was used. The results indicated that not only could this supposedly difficult skill be acquired by severely multihandicapped individuals, but that they could also generalize to other appropriate environments. Acquisition of this skill could help optimize their use of free time for leisure pursuits in a variety of settings.

The mistaken mirror: on Wundt's and Titchener's psychologies.

Abstract: Most psychologists believe that Structuralism, the psychology of E. B. Titchener, was a faithful copy of Wilhelm Wundt's original psychology. This belief is fostered by textbooks for history and systems and introductory psychology courses. The present paper argues that this belief is false. Titchener rejected many of Wundt's goals and concepts, and should be viewed as a traditional British associationist and positivist rather than as a follower of Wundt. Similarities of Wundt's system and Titchener's system to current psychological thinking are noted.

Potential mold growth, aflatoxin production, and antimycotic activity of selected natural spices and herbs.

Abstract: Ground spices and herbs are evaluated as substrates for mycelial growth, sporulation, and aflatoxin production. Three toxigenic strains of Aspergilli, A. flavus ATCC 15548, A. flavus NRRL 3251, and A. parasiticus NRRL 2999, were cultured on moist, commercially packaged herbs and spices. All substrates used were ground and included thyme, celery seed, oregano, cinnamon, ginger, caraway seed, clove, mustard, sesame seed, and rosemary leaves. Following inoculation of the natural materials in sterile bottles containing sterile water, the cultures were incubated 30 days at 23 +/- 4 degrees C. Not all strains of Aspergilli grew, sporulated, or produced toxins. There were definite strain differences and definite substrate differences for the variables evaluated. Sesame seed produced toxins B1, G1, and G2, with a mean of 167 ppm for 3 strains. A. flavus ATCC 15548 was the greatest overall toxin producer followed by A. parasiticus NRRL 2999 and A. flavus NRRL 3251. Ginger and rosemary leaves were also substantial producer-substrates. Mustard, caraway seed, and celery seed were judged as intermediate-producing substrates. Absolute antimycotic substrates were cinnamon and clove. Antiaflatoxigenic substrates were thyme and oregano. Mustard also may be antimycotic. Aflatoxins B1 and G1 were the more commonly found toxins.

Ab initio calculation of interatomic potentials and electronic properties of a simple metal-Al

Abstract: A simple scheme using a single-ion approach has been developed to calculate the pseudopotential and pair potential for aluminum. The electron density around an isolated Al nucleus in a homogeneous electron gas is calculated self-consistently using the density-functional method. The induced charge density is then used to produce an ab initio local pseudopotential and the interionic potential. Two different schemes for embedding the Al nucleus into the jellium have been considered. A model where the Al nucleus is in the jellium vacancy gives better pseudo- and pair potentials than the model where the Al nucleus is embedded into a completely homogeneous electron gas. Using the resulting potentials, the cohesion energy, equilibrium lattice constant, bulk modulus, vacancy formation energy, and the resistivity of the liquid phase were calculated. The sensitivity of the results to various approximations in the model, the volume dependence of the pair potential, and the effects of the ionic core are discussed.

Induction of Chemotaxis in Mouse Peritoneal Macrophages by Phorbol Ester Tumor Promoters

Abstract: The ability of the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), to induce chemotaxis in three different populations of mouse peritoneal macrophages was studied. TPA in the range of 10(-9) to 10(-7) M produced a dose- and time-related increase in chemotaxis in resident, thioglycollate-elicited, and divinyl ether maleic anhydride copolymer-activated macrophages. A maximal response was obtained after 4 hr incubation with 10(-7) M TPA, and this concentration of TPA was as effective as inducing chemotaxis as was endotoxin-activated mouse serum. Orientation of macrophages towards TPA was also observed by microscopy. Within 2 hr, cells exposed to TPA sent out cytoplasmic processes along the TPA gradient. Parallel arrays of cells oriented towards the TPA were observed after 4 hr incubation. Two other diterpene tumor promoters, phorbol-12,13-didecanoate and mezerein, were also chemotactic for the macrophages, as was the peptide epidermal growth factor, which shares a number of effects with TPA on cells in culture. On the other hand, two phorbol esters inactive as tumor promoters, 4-alpha-phorbol-12,13-didecanoate and phorbol, were not chemotactic for macrophages. Retinoic acid, which inhibits tumor promotion, inhibited TPA-induced, but not endotoxin-activated mouse serum-induced chemotaxis. These findings, taken together with previous studies, indicate that phorbol ester tumor promoters are potent modulators of macrophage function.

Research notes and communications. Toward the development of a planning scale: An example from the banking industry

Abstract: The study dealt with the degree of formal planning undertaken by the commercial banking industry during 1969, 1972, 1975, and 1978. The study found that the Guttman scaling method can be used to develop a corporate planning scale. An outline of the steps in the construction of a Guttman planning scale is presented. Future research into the relationship between formal planning efforts and organizational performance might incorporate this approach.

Carcinoma of the maxillary antrum: Surgery or radiation therapy?

Abstract: Between the years 1968 and 1978, 57 patients with malignant tumors of the para-nasal sinuses were seen at the Medical College of Virginia. Thirty-nine patients presenting with squamous cell epitheliomas of the maxillary antrum, free of lymph node or distant metastases, and primarily treated at the Medical College of Virginia, form the basis of this study. Nineteen patients underwent radical', craniofacial surgery with orbital exenteration and reconstruction. Twenty patients underwent Caldwell-Luc procedure followed by radical radiation therapy. The crude 3 year disease-free survivals are 50% and 37% in the radiation therapy and the surgery group respectively. Local control, survival, and patterns of failure are discussed.

Grade Inflation in Higher Education: A Comparative Study.

Abstract: Recent research in higher education has exposed and documented a phenomenon that some have labeled “grade inflation.” Because of the significant implications of grade inflation for the credibility of academia's standards of excellence and accountability, efforts should be directed toward explaining why this phenomenon is occurring, and remedies sought. The present study represents a comparison of 10 departments displaying high grade inflation rates during a 7-year period with 10 departments within the same university displaying low(er) grade inflation rates. The study found an average inflation of grades of +.298 during this time period, with higher grade inflation rates related to perceived and/or actual increases in the demands or pressures placed upon the academician's role, to greater flexibility in grading options and, in particular, to the use of more subjective student-based methods of evaluation. While the study's findings also support the “peaking effect” theory that grade inflation rates will slow down, the central question remains: How high will grade point averages rise and, in the absence of positive corrective action, what will be the effect of the grade inflation phenomenon on the credibility of institutions of higher education and their graduates?

Gastroplasty for respiratory insufficiency of obesity.

Abstract: Three patients with the obesity hypoventilation syndrome and one patient with the sleep apnea syndrome underwent gastroplasty for weight reduction. A tracheostomy was also performed in the patient with sleep apnea. The PaO2 rose from an average of 51 +/- 9 to 71 +/- 5 torr and the PaCO2 fell from an average of 51 +/- 21 to 41 +/- 6 torr within two to ten months following bariatric surgery. The improved arterial blood gases were associated with an increased forced vital capacity in each patient. The change in maximum voluntary ventilation was variable. Sleep capneography demonstrated cure of the patient with sleep apnea permitting removal of the tracheostomy. All four patients have returned to productive lives in society. Given proper pre- and postoperative care, patients with respiratory insufficiency tolerate the operation well. Respiratory insufficiency associated with morbid obesity should be considered an indication for the gastroplasty procedure, rather than a contraindication as previously suggested.