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T J Janus

Publications and source records attributed to T J Janus.

12 recordsLinked to original sources
PubMed1996

Neurobehavioral sequelae of high voltage electrical injuries: comparison with traumatic brain injury.

Eighteen survivors of high voltage electrical injuries (HVEI) underwent neuropsychological evaluation in the acute, short-term or long-term epochs Deficits in verbal learning and delayed recall of verbal information were present across various epochs No other cognitive performances were in the impaired range for the HVEI group, although many individual patients also had compromised attention Depression, anxiety and irritability were widespread among HVEI patients, especially beyond the acute period Extreme irritability was accompanied by assaultive behavior in several patients The neurobehavioral effects of HVEI were very similar to those of a closely matched traumatic brain injury (TBI) control group in each epoch The only significant difference between the groups was less successful immediate visual retention by TBI patients in the long-term epoch.

Journal Article↗
PubMed1993

Use of [18F]fluorodeoxyglucose positron emission tomography in patients with primary malignant brain tumors.

In patients with malignant gliomas, [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) may discriminate tumor progression from radionecrosis. We evaluated data from 50 patients undergoing FDG-PET for suspicion of tumor progression. Forty-nine were treated with surgery, 48 with radiotherapy, and 37 with chemotherapy. Twenty-one had intensive radiotherapy with either three daily treatments in two 5-day periods and intravenous carboplatin (17) or interstitial brachytherapy or stereotactic radiotherapy. Twenty underwent surgery after magnetic resonance imaging/FDG-PET; 9 demonstrated increased uptake of FDG and evidence of tumor, whereas 6 had decreased uptake and no evidence of tumor. In 5 patients, there was no correlation (all had intensive radiotherapy). In 17 patients who received bromodeoxyuridine intravenously just before surgery, the bromodeoxyuridine labeling index corresponded to the histological appearance in all but 2 patients (both had received intensive radiotherapy). In 30 patients without surgery, decreased uptake of FDG suggested prolonged survival; increased uptake of FDG did not predict survival. Eight of 10 with intensive radiotherapy had decreased label uptake. We conclude FDG-PET for evaluation of patients with possible recurrent tumors requires more study. In patients with intensive radiotherapy, FDG-PET results cannot be correlated accurately with tumor progression.

Adult↗
PubMed1992

Adjuvant chemotherapy with carmustine and cisplatin for patients with malignant gliomas.

Forty-five patients with malignant gliomas were treated after aggressive surgical resection with alternating intravenous carmustine and cisplatin both during and after radiation therapy. Thirty-three patients were considered evaluable for responses, 17 had glioblastoma multiforme (GBM), 14 had anaplastic astrocytoma (AA) and 2 had anaplastic oligodendroglioma (AO). The median age of the evaluable patients was 47 years. The median time to tumor progression was 34.5 weeks, and the median survival for the entire group was 76 weeks. Early progression occurred more frequently in patients with glioblastoma than in those with AA or AO. Seventeen patients (55%) were alive at 18 months (6 GBM, 9 AA, 2 AO). Toxicity was mainly hematologic, otic and tolerable. The results suggest that further trial is warranted to assess the efficacy of alternating carmustine and cisplatin in conjunction with radiation therapy postoperatively in patients with malignant gliomas.

Adult↗
PubMed1992

Biology and treatment of gliomas.

This review discusses some of the recent advances in glioma research and treatment. Our understanding of the characteristics of these tumors has been strengthened by the application of molecular biologic and genetic techniques to pathologic grading and therapy outcome. Newer attempts to correlate imaging modalities to pathologic grading are also discussed. It is anticipated that these developments will strengthen our ability to design improved treatment strategies, an essential goal inasmuch as current treatment schemes have limited benefit. More work needs to be done to understand the biology of these tumors especially the complex interactions of their cytokine expression, multiplicity of genetic abnormalities, and their local environment. Only then will be able to develop improved therapeutic interventions.

Biomarkers, Tumor↗
PubMed1986

Modulation of lymphocyte responsiveness to phytohemagglutinin by micromolecular fibrinogen degradation products.

The ability of fibrinogen degradation products (FDP) to influence the regulatory function of adherent cells from peripheral blood mononuclear cells (PBMC) was evaluated. FDP were prepared by digestion of fibrin clots with plasmin. These FDP were incubated overnight with glass-adherent cells following which these treated and untreated cells were cocultivated with fresh autologous responder PBMC in the presence of the T-cell mitogen, phytohemagglutinin (PHA). Lipid metabolism of FDP-treated monocytes was evaluated in cells that had been prelabeled with [3H]arachidonic acid (AA) prior to their overnight incubation with FDP; supernatants were analyzed for conversion of AA to cyclooxygenase and lipoxygenase products by thin-layer chromatography. Treatment of glass-adherent cells with the FDP digests converted these monocytes into suppressor cells. The suppression exerted by these cells in the PHA assay was dose dependent. The suppression exerted by FDP-pretreated monocytes was reversed by treating the PHA-stimulated cocultures with indomethacin and was associated with increased cyclooxygenase activity. These studies demonstrated that FDP can alter T-cell immune function through the induction of monocyte suppressor cells; the means by which that occurs is associated with stimulation of lipid metabolism and secretion of eicosanoids with immunoregulatory capacity.

Arachidonic Acids↗
PubMed1985

Regulation of formation of factor XIIIa by its fibrin substrates.

Thrombin-catalyzed release of activation peptide (AP) from plasma factor XIII was studied to characterize the regulation of this initial step in the activation of factor XIII zymogen (fibrin-stabilizing factor). High-performance liquid chromatography was used to monitor the kinetics of release of AP. Non-cross-linked polymeric fibrins I and II (polymerized des-A- and des-A,B-fibrinogens), physiological substrates of factor XIIIa, were shown to be potent promoters of thrombin-catalyzed release of activation peptide from factor XIII. These promoters are proposed to act by complexing factor XIII and reducing the apparent Km for thrombin-catalyzed release of AP. Since thrombin-catalyzed release of AP is inefficient in the absence of polymerized fibrin, this mode of regulation should minimize formation of factor XIIIa prior to the formation of its fibrin substrates. The promoting activity of polymeric fibrin was rapidly lost when catalytically competent factor XIIIa was allowed to form. This observation suggested the possibility that factor XIIIa catalyzed cross-linking of fibrin inactivates fibrin as a promoter for the thrombin-catalyzed release of AP from factor XIII. Consistent with this view, the thiol reagent S-methyl methanethiosulfonate inactivated factor XIIIa, blocked cross-linking of fibrin, and protected against loss of its promoter activity. This mode of feedback regulation of the activation process by catalytically active factor XIIIa may serve to ensure against continued generation of factor XIIIa after its fibrin substrates have been cross-linked.

Calcium↗
PubMed1983

Promotion of thrombin-catalyzed activation of factor XIII by fibrinogen.

High-performance liquid chromatography was used to analyze the kinetics of the thrombin-catalyzed release of the activation peptide from the factor XIII zymogen (fibrin-stabilizing factor). The specificity constant (kcat/Km) for this reaction, measured at factor XIII concentrations much below Km, was (0.13-0.16) X 10(6) M-1 s-1 at pH 7.4, mu = 0.15, and 37 degrees C. Separate estimates, obtained from the dependence of the initial rates of release of the activation peptide on the concentration of factor XIII, gave values of 10 (+/- 3) s-1 for kcat and 84 (+/- 30) microM for Km, in terms of ab protomers of the zymogen. The thrombin-mediated release of the activation peptide was dramatically enhanced in the presence of fibrinogen. Furthermore, the time course of release, in relation to that of fibrinopeptide A, suggested that some des-A-fibrinogen species (e.g., alpha 2B beta 2 gamma 2) may be the true activator for promoting the cleavage of the Arg-36 peptide bonds in the a subunits of factor XIII. This observation suggests that generation of factor XIIIa and its substrate (fibrin) is coordinated so that thrombin-mediated zymogen activation proceeds efficiently only after the process of clotting has been initiated by the removal of fibrinopeptide A from fibrinogen.

Blood Coagulation↗
PubMedDate not supplied

Neurologic and neurobehavioral effects of electric and lightning injuries.

There are few studies of the effects of electric and lightning injuries (ELI) on the neurologic and neuropsychological status of injured patients. We reviewed records of fourteen patients with ELI injuries seen at our hospital (12 with high-voltage electric and two with lightning injury). Eight had cardiac arrest after injury, and 10 had neurologic complaints when first evaluated. Eight had normal neuroimaging results. Six had electroencephalograms; four showed abnormal results. Thirteen underwent neuropsychological testing. Twelve (92%) showed cognitive dysfunction including impairments in memory, attention, and affective disturbances (anxiety, depression, irritability, and poor frustration tolerance). Five of 12 (62%) had multiple physically aggressive outbursts, not present before the injury. Patients with cardiac arrest did not differ in neurologic psychologic testing from patients not sustaining cardiac arrest. Patients with ELI who had neurobehavioral symptoms had a coherent syndrome characterized by disturbances in cognition (attention and memory), mood (distress with prominent irritability), and behavior (aggressive outbursts). Serial neurologic and neuropsychological evaluations will aid in better defining the sequelae of ELI.

Adult↗