Biomedical subjects
Publications and source records attributed to S Kohan.
The management of spinal epidural abscess has changed over the last few years. Originally treatment was thought to be urgent surgical evacuation. In the more recent literature less invasive techniques have been suggested. We present a case, where a cervical epidural abscess at the C2 level was treated with CT guided aspiration and antibiotic therapy. This has not been previously reported.
BACKGROUND: The current research on Alzheimer's disease is mainly focused in the post-mortem characterization of pathological and biochemical alterations in the brain. The finding of peripheral markers that could be associated with the changes observed in the Alzheimer's brain would be of interest in this field. The aim of the present study was to evaluate the state of different peripheral markers of oxidative stress in probable Alzheimer patients and compare them with a group of healthy individuals. DESIGN: The determinations made include the plasma total antioxidant capacity (TRAP) and tert-butyl hydroperoxide-initiated chemiluminescence and catalase activity in erythrocytes from 18 patients with probable Alzheimer's disease and 18 matched control subjects with normal cognitive function. RESULTS: TRAP was decreased in Alzheimer patients by 24% (control group 308 micromol L-1 Trolox, SEM 34, n = 18). tert-Butyl hydroperoxide-initiated chemiluminescence and catalase activity showed an increase in erythrocytes from Alzheimer patients by 52% (control group 116 700 cps mg-1 haemoglobin, SEM 6690) and 75% (control group 2.55 pmol mg-1 protein, SEM 0.39, n = 18) respectively. CONCLUSION: Oxidative stress in the blood of probable Alzheimer patients could be a reflection of the brain condition and suggests that oxygen free radicals could be partially responsible of the damage observed in this disease.
A study of several elements of the antioxidative system: Cu-Zn superoxide dismutase (SOD), catalase (CAT), glutathione system (GLU), chemiluminescence (CHE), and antioxidant capacity (AOX), was conducted in 20 demented probable Alzheimer's (DAT), and 15 vascular demented (VD) patients, 19 control (C) subjects, and 11 relatives (F) of one DAT patient. A significant association was found between the variables of the antioxidant system, measured in blood samples, and the neurological pathologies VD and DAT: Kruskal-Wallis test; p = 0.0006 (p = 0.014 when the analysis did not include SOD). This demonstrated that VD and DAT diseases are accompanied by oxidative disorders. The VD and DAT diseases are differentially distinguishable by changes in blood profiles. A graphical method for classification, the Principal Components Analysis (PCA), distinguished between demented and non-demented subjects on the basis of their laboratory variables. A numerical method, Discriminant Functions (DF), constructed to separate the clinical groups on the basis of the same variables, obtained relatively high percentages of success: 92% of demented were detected against healthy subjects; of the latter 82% have been correctly identified as non-demented. Discrimination between VD and DAT patients was achieved for 100% of VD and 86% of DAT patients. DF were similarly successful in detecting the healthy condition of DAT relatives. Possible different mechanisms involved in H2O2 elimination in DAT and VD patients are proposed, where CAT is the responsible enzyme of this reaction in DAT patients, while in VD this function would be achieved mainly through the action of GLU. It seems that SOD levels are stable, at least, within one year. Variations appear to be linked with clinical changes.
The potential benefit of interferon (IFN)-alpha therapy in early-stage B cell chronic lymphocytic leukemia (B-CLL) patients is still under discussion, and no assays are available to distinguish potential responders from nonresponders. Herein we analyzed the usefulness of serum tumor necrosis factor (TNF, a cytokine released by CLL cells) and MxA protein (an intracellular marker for biologic activity of endogenous IFN) concentrations as predictive measurements for evolution and response to IFN therapy in early-stage CLL patients. TNF levels and MxA expression were determined at diagnosis in 21 CLL patients. A statistically significant correlation was found between low TNF levels and MxA expression and between high TNF levels and no measurable MxA expression. The patients were then randomized to receive IFN-alpha or no therapy and were evaluated for response and evolution. When response to IFN-alpha therapy was considered, it became apparent that early-stage CLL patients with higher TNF levels and no measurable MxA expression were more likely to benefit from IFN therapy, whereas those patients with lower TNF levels and MxA expression could be considered CLL candidates for longer survival without therapy. More patients have to be tested to strengthen the value of MxA expression and TNF concentrations for subsequent response to IFN-alpha therapy.
We examined the activity of the serine protease urokinase-type plasminogen activator (uPA) present in the euglobulin fraction of plasma from 17 demented patients with probable Alzheimer's disease (AD), 12 patients with vascular dementia (VD) and 10 healthy controls. Euglobulin protein fractions were separated by electrophoresis and gels were incubated at the surface of plasminogen-rich casein-agarose underlays. The degradative activity of uPA in this system was measured by densitometric analysis. In 8/17 (47%) patients with AD we observed an excessive uPA activity (> 200 mIU/ml). In contrast, only 2/12 (16%) patients with VD and 1/10 (10%) control subjects revealed a comparable increase in circulating uPA activity. Further evaluation of dementia stage in patients with AD allow us to associate high levels of uPA activity with severity of disease. uPA levels were significantly elevated (2.8-fold increase) in AD patients with severe cognitive and memory impairments (Alzheimer Disease Assessment Scale) with respect to controls, VD patients or AD patients with moderate cognitive and memory impairments (P < 0.001, ANOVA). Our data suggest that the anormalities in circulating fibrinolytic enzymes could be correlated with the severity of dementia. In light of this findings, the free uPA activity in euglobulin plasma fraction should be considered a marker of serious damage in patients with AD.
The activity of the enzyme copper-zinc superoxide dismutase (Cu-Zn SOD) has been investigated in red blood cell (RBC) homogenate obtained from demented patients with probable Alzheimer's disease (DAT), from their first-degree relatives (sisters/brothers and sons/daughters), and from healthy control families of the same age. A statistically significant increase in SOD activity (P < 0.01) was found in RBC's homogenate between families of DAT patients (not including the demented individual) and control families. Variability in SOD activity due to differences between families was not significant for DAT relatives; a significant variance component (P < 0.05) was found between control families. Additionally, a statistically significant increase in SOD activity (P < 0.001) with age in DAT patients up to 70 years and a significant decrease above this age were found, confirming a previously found relation. No changes in SOD activity with age were detected in healthy controls nor in DAT relatives. The increased levels of Cu-Zn SOD, probably represent a general alteration of the oxidative processes characteristic of this dementia and support the proposal that the enzyme could be used as an early diagnostic peripheral marker of the Alzheimer's disease (AD), and to determine to which subgroup the patient belongs, as well as a risk factor in non-demented first-degree relatives.
The activity of the enzyme copper-zinc superoxide dismutase (Cu-Zn SOD) has been investigated in serum and red blood cells (RBC) homogenate obtained from demented patients with associated vascular lesions (VD), demented patients with probable Alzheimer's disease (DAT) and healthy controls (CG) of the same age. The increase in SOD activity was statistically significant (P < 0.01) in RBCs homogenate of DAT and VD patients, when compared to controls, but no differences appear between the two diseases groups. Additionally, a statistically significant increase in SOD activity (P < 0.01) in DAT patients above 70 years as compared to those 50-70 years old, and a relation between SOD and age were found. No changes in SOD activity with age in healthy controls nor in vascular dementia group were detected. A statistically significant increase in Circulating SOD activity (P < 0.01) was observed in vascular patients compared to controls. The observed increase in DAT Circulating SOD activity (against CG) was not significant. The increased levels of Cu-Zn SOD, probably represent a general alteration of the oxidative processes characteristic of these dementias and suggest that the enzyme might be used as a marker.
Explore the source record for details and available documents.
A 94-residue polypeptide isolated from human seminal plasma and its chemically synthesized C-terminal 28-residue segment were studied in an in vitro inhibin bioassay utilizing rat pituitary cell cultures. Both peptides have previously been claimed to have inhibin activities, and the effects on the secretion and cellular content of gonadotrophins (FSH and LH) were now assessed in the in vitro assay. No inhibition was found. After 72 h of culture, both the cellular content and the spontaneous as well as the LHRH-stimulated release of bioactive or immunoactive FSH and LH remained unaffected. Similarly, no effects were found on the storage and/or release of prolactin, growth hormone, or thyrotropin. We conclude that both the native 94-residue peptide and the synthetic replicate of its C-terminal 28-residue segment, do not influence the pituitary FSH secretion when assessed in this in vitro system.
In a syngeneic C3H mammary adenocarcinoma model we studied gamma-interferon (gamma IFN) production during tumor evolution. The IFN production was induced by soluble tumor extracts on spleen cell cultures from tumor-bearing mice. A low level of IFN production was found in culture supernatants from small tumor-bearing mice (tumor diameter less than 10 mm, 12-15 days of tumor evolution). In advanced stages of tumor growth (diameter more than 15 mm, 20 days or more of tumor evolution), this ability was lost.
A retrospective study was done on 575 patients with atypical Papanicolaou smears obtained during a ten-year period (1974-83) at Bellevue Hospital-New York University Medical Center. The smears were classified into three categories. The first consisted of 463 patients (81%) with inflammatory atypia specifically treated for Trichomonas, Monilia, Chlamydia, Gardnerella and atrophic vaginitis. Of them, 162 patients (35% of the group) had persistent inflammatory atypia 90 days after the beginning of therapy and were subjected to colposcopic examination. The second group consisted of 86 patients (15%) with squamous atypia. That group underwent colposcopic examination. The third group, 26 patients (4%), had endocervical atypia and underwent colposcopy and endocervical curettage. Overall, of 162 patients with persistent inflammatory atypia, 36 (22%) were found to have cervical intraepithelial neoplasia (CIN); of 86 with squamous atypia, 60 (70%) had CIN; and of 26 with endocervical atypia, 15 (58%) had CIN. Fifty-eight (28%) of all the patients with CIN had lesions of severity greater than CIN 1. It appears that all patients with persistent inflammation or squamous or endocervical atypia would benefit from colposcopic screening.
We made a colposcopic study of 149 pregnant patients with suspicious or positive Papanicolaou smears. Characteristic changes in the colposcopic images were noted to be physiologic eversion of the squamocolumnar junction, glandular hypertrophy and decidual reaction. Fourteen percent of the patients with suspicious Papanicolaou smears were normal by colposcopic examination. Sixteen percent of colposcopic interpretations of the pregnant cervix suggested CIN when in fact none was present on tissue specimens obtained by directed biopsies. There was a good correlation between colposcopic clinical diagnosis and directed tissue biopsies (79%). Furthermore, there was a strong correlation between colposcopically directed tissue biopsies and subsequent cone and hysterectomy specimens (29 cases). All cases with suspicious cytology and CIN based on colposcopic findings (130 patients with satisfactory colposcopic examinations) were managed conservatively. No invasive neoplasia was subsequently detected in this group. Morbidity for colposcopically directed biopsies in pregnancy was negligible. No massive hemorrhage, premature labor, abortion or infection occurred. Treatment for CIN was accomplished following the puerperium by cryocauterization (101 cases), conization (8 cases) or hysterectomy (21 cases). Colposcopy cannot be a substitute for histologic diagnosis. However, it supplies enough data to avoid unnecessary cone biopsies. Only 19 diagnostic cone biopsies were performed during pregnancy with the indication of positive cytology and unsatisfactory colposcopy.
We have identified trisomy 13 in two additional patients with hematologic malignancies involving the hematopoietic stem cell: a 75-year-old female with acute myelocytic leukemia and a 64-year-old female with agnogenic myelofibrosis and myeloid metaplasia. Chromosome analysis of the direct bone-marrow preparation showed 100% of cells with trisomy 13 in the first and 10% of cells in the second. We also previously reported a patient with Ph1 negative chronic myelogenous leukemia in whom 100% of the marrow cells showed an identical trisomy. The probability of finding three such patients in our case material was calculated to be 0.05--0.08, implying that trisomy 13 may be another nonrandom chromosomal aberration associated with malignancies of hematopoietic pluri-potent stem cell.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.