26
|
Brad A, Spies T, Olivier F, Lane M, Gardner D, Bartels P, Krisher R. 203TIMING OF IN VITRO OOCYTE MATURATION IN SPRINGBOK (ANTIDORCAS MARSUPIALIS), BLACK WILDEBEEST (CONNECHAETES GNU), BLESBOK (DAMALISCUS DORCUS PHILLIPSI), AND REEDBUCK (REDUNCA ARUNDINUM). Reprod Fertil Dev 2004. [DOI: 10.1071/rdv16n1ab203] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
With an increased need for genetic diversity within populations, assisted reproductive technology is becoming an important tool for banking semen and embryos, with the possibility of future AI or embryo transfer between distant populations. Previous research has demonstrated that the broad approach of applying bovine IVM/F/C protocols to African antelope is inefficient for embryo production. The purpose of this study was to determine the timing of oocyte maturation (to telophase or metaphase II) in vitro in springbok (Antidorcas marsupialis; n=84), black wildebeest (Connechaetes gnu; n=18), blesbok (Damaliscus dorcus phillipsi; n=9), and reedbuck (Redunca arundinum; n=1). Ovaries were collected within 4h of death from culled animals on game reserves in South Africa, placed into warm SOF-HEPES, sliced and cumulus-oocyte complexes (COCs) collected. Complexes were placed into GMat medium supplemented with 0.01UmL−1 each FSH and LH, 50ngmL−1 EGF, and 1.0% (v/v) PSA (100U penicillin mL−1, 100μg streptomycin mL−1, 0.25ng amphotercin mL−1). Oocytes were removed from medium after 16, 20, 24, 28 or 32h of maturation in 5% CO2 in air at 39°C. After removal, complexes were denuded with hyaluronidase, mounted on a slide and placed into 3:1 (ethanol:glacial acetic acid) fixative until time of analysis. Oocytes were stained with aceto-orcein, and nuclear maturation was evaluated with a phase contrast microscope. As shown in the Table 1, in springbok (n=311), the percentage of mature oocytes peaked at 28h of maturation and was not different (P<0.05) from oocytes matured for 32h. Fewer springbok oocytes were mature at 16, 20 and 24h. Black Wildebeest (n=88) oocytes were mature by 24h, with no additional increase in maturation at 28 or 32h. Blesbok oocytes (n=42) were not mature at 16 or 20h, and there was no difference (P>0.05) in the percentage of oocytes mature at 24 or 28h. Observational data in reedbuck (n=10) indicated that no oocytes were mature at 20 or 24h, but 25.0% were mature at 28h. The low occurrence of mature oocytes at 28h in blesbok and reedbuck suggests that additional time points should be examined later in maturation. This study demonstrates that oocytes of these species can be successfully matured in vitro, but the rate of maturation and thus the optimal time of insemination for IVF is species specific.
Table 1
Timing of in vitro oocyte nuclear maturation to telophase or metaphase II in springbok, black wildebeest and blesbok
Collapse
|
27
|
Meier U, Bartels P. The importance of the intrathecal infusion test in the diagnosis of normal pressure hydrocephalus. J Clin Neurosci 2002; 9:260-7. [PMID: 12093131 DOI: 10.1054/jocn.2001.1004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The intrathecal infusion test is a reliable method in diagnosing normal pressure hydrocephalus. Between May 1982 and January 2000 we investigated 300 patients suspected of having normal pressure hydrocephalus (NPH) by carrying out an intrathecal infusion test in a constant flow technique. The resistance to cerebrospinal fluid outflow (R(out)) in the intrathecal infusion test was the main criterion of grouping patients into those with normal pressure hydrocephalus or those with cerebral atrophy. A further differentiation into early stage and late stage was made by measuring the compliance (C(p)) - this being the secondary criterion. In 162 patients (54%) the diagnosis of NPH could be confirmed. Of these, 154 patients (95%) underwent a shunt operation. Graduation of NPH and cerebral atrophy following the results of the infusion test at an early stage and an advanced stage allow the conclusion of prognostic evaluations about the course of disease to be made. Patients with NPH in an early stage report in the follow up an improvement of their symptoms after a shunt operation in 65 percent of cases, and those with advanced stage NPH, in 50 percent of cases. The computer aided infusion test allows a reliable differentiation between patients with NPH and those with cerebral atrophy.
Collapse
|
28
|
Meier U, Bartels P. The importance of the intrathecal infusion test in the diagnostic of normal-pressure hydrocephalus. Eur Neurol 2002; 46:178-86. [PMID: 11721123 DOI: 10.1159/000050801] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
OBJECTIVE The intrathecal infusion test is a reliable method for diagnosing normal-pressure hydrocephalus (NPH). METHODS Between May 1982 and January 1997, we investigated 200 patients suspected of having NPH by carrying out an intrathecal infusion test with a constant-flow technique. The resistance to cerebrospinal fluid outflow in the intrathecal infusion test was the main criterion for grouping patients into those with NPH or those with cerebral atrophy. A further differentiation into early stage and advanced stage was made by measuring the compliance, this being the secondary criterion. RESULTS In 107 patients (54%), the diagnosis of NPH could be confirmed. Of these, 102 patients (95%) underwent a shunt operation. Graduation of NPH and cerebral atrophy following the results of the infusion test at an early stage and an advanced stage allows prognostic evaluations about the course of disease to be made. Patients with NPH at an early stage reported an improvement of their symptoms in the follow-up after a shunt operation in 65% of cases, while 50% of those with advanced-stage NPH reported improvement. CONCLUSION The computer- aided infusion test allows a reliable differentiation between patients with NPH and those with cerebral atrophy.
Collapse
|
29
|
Meier U, Kiefer M, Bartels P. The ICP-dependency of resistance to cerebrospinal fluid outflow: a new mathematical method for CSF-parameter calculation in a model with H-TX rats. J Clin Neurosci 2002; 9:58-63. [PMID: 11749020 DOI: 10.1054/jocn.2001.0930] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The international The simultaneous measurement of the resistance and compliance during a single investigation minimizes the patients exertion. In contrast to the classical method it is not necessary that the ICP reaches a plateau. Our mathematical method diverges with t he description of a pressure dependent slope of the function for the resistance from the static examination models. We proved our mathematical method by the use of a dynamic infusion test in 10 H-Tx rats without hydrocephalus and five hydrocephalic H-Tx rats. For that we are able to take the non linearity of the CSF resorption into consideration.
Collapse
|
30
|
Schönherr B, Gräwe A, Bartels P, Meier U. [The importance of neuronavigation in endoscopic operations in neurosurgery]. ZEITSCHRIFT FUR ARZTLICHE FORTBILDUNG UND QUALITATSSICHERUNG 2001; 95:725-9. [PMID: 11778326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Intracranial endoscopy as minimal invasive surgery for the treatment of hydrocephalus and intracranial cysts cannot be disregarded after 10 years of clinical practicing. The advantages are low traumatization of brain tissue and good visual control of the operation field. Neuronavigation qualifies as a method of increased operation safety for lesions which are deep seated or difficult to access. A combination of both systems partially neutralizes the respective disadvantages. On the one hand, the neuronavigation ensures the endoscopic approach up to the intracranial caverns and especially supports the endoscopy in cases of bad vision or pathologic anatomy. Endoscopy, on the other hand, enables the surgeon to recognize discrepancies and mistakes of the neuronavigation due to optical control. Increased expenses and time and staff requirements are counterbalanced by the increased cumulated operation safety. An advantageous side-effect of the combination of neuronavigation and intracranial endoscopy is the high learning potential for assistants. For all these reasons the application of neuronavigation in intracranial endoscopy is considered very important and strongly recommended.
Collapse
|
31
|
Boone CW, Lieberman R, Mairinger T, Palcic B, Bacus J, Bartels P. Computer-assisted image analysis-derived intermediate endpoints. Urology 2001; 57:129-31. [PMID: 11295610 DOI: 10.1016/s0090-4295(00)00956-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The development of prostatic lesions undergoes a slow progression. To establish efficacy of chemopreventive intervention it is therefore necessary to define surrogate endpoint biomarkers. Such biomarkers should be sensitive in their ability to indicate response. They should be objective, ie, the result of measurement, and numerically defined so that a statistical validation of response is possible. They should be able to indicate not only a halt of progression of a lesion, but also a reversal of progression. The spatial and statistical distribution of nuclear chromatin in the secretory and luminal cells in prostatic intraepithelial neoplastic lesions has been shown to be well defined. It can be represented by a set of features. These have been used to define a progression curve along which progression or regression of a lesion can be assessed. One could define a fixed endpoint, or one might choose to accept a statistically significant regression along the progression curve as criterion for chemopreventive efficacy. Expected difficulties could arise from lesion heterogeneity, as it would affect the sampling, and from multifocal lesions of differing progressions. Lesion heterogeneity thus limits the precision with which regression could be detected. These problems might be partially overcome by observations taken in histologically normal appearing regions of the prostate. The nuclear chromatin pattern of secretory cell nuclei measured in such tissue regions from prostates harboring intraepithelial or malignant lesions has been shown to exhibit distinctive changes from the chromatin pattern seen in secretory cell nuclei from prostates free from any such lesions. These changes appear to be expressed in the tissue up to a substantial distance from a lesion. The expression of changes in the nuclear chromatin suggests the existence of an intraepithelial preneoplastic lesion that can be detected by biomarkers, but which is not apparent from visual microscopic inspection. Since chemoprevention might be expected to be most effective at the earliest stages of lesion development, the assessment of such early alterations is seen as highly relevant to efforts to validate the efficacy of chemopreventive intervention.
Collapse
|
32
|
Linskens RK, van Bodegraven AA, Schoorl M, Tuynman HA, Bartels P. Predictive value of inflammatory and coagulation parameters in the course of severe ulcerative colitis. Dig Dis Sci 2001; 46:644-8. [PMID: 11318546 DOI: 10.1023/a:1005628005734] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Alterations in markers of coagulation have been found in patients with inflammatory bowel disease. Our aim was to study the predictive value of coagulation and inflammatory parameters in the course of severe ulcerative colitis. Twenty-seven patients were included. The disease course was followed for one year. Sensitivity, specificity, negative predictive value, positive predictive value, and likelihood ratio, as well as the clinical predictive value of laboratory variables were calculated. Inflammatory variables, such as ESR, CRP, and leukocyte and platelet count showed poor diagnostic accuracy. Several coagulation parameters, such as fibrinogen and fibrin(ogen) degradation products, were increased in patients with active ulcerative colitis, whereas coagulation factor XIII was decreased. No significant relationship between clinical course and coagulation parameters was demonstrated, though both inflammatory and coagulation parameters were useful in the assessment of disease activity in patients with active ulcerative colitis.
Collapse
|
33
|
Nash RA, Antin JH, Karanes C, Fay JW, Avalos BR, Yeager AM, Przepiorka D, Davies S, Petersen FB, Bartels P, Buell D, Fitzsimmons W, Anasetti C, Storb R, Ratanatharathorn V. Phase 3 study comparing methotrexate and tacrolimus with methotrexate and cyclosporine for prophylaxis of acute graft-versus-host disease after marrow transplantation from unrelated donors. Blood 2000; 96:2062-8. [PMID: 10979948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
After the transplantation of unmodified marrow from human leukocyte antigen-matched unrelated donors receiving cyclosporine (CSP) and methotrexate (MTX), the incidence of acute graft-versus-host disease (GVHD) is greater than 75%. Tacrolimus is a macrolide compound that, in previous preclinical and clinical studies, was effective in combination with MTX for the prevention of acute GVHD. Between March 1995 and September 1996, 180 patients were randomized in a phase 3, open-label, multicenter study to determine whether tacrolimus combined with a short course of MTX (n = 90), more than CSP and a short course of MTX (n = 90), would reduce the incidence of acute GVHD after marrow transplantation from unrelated donors. There was a significant trend toward decreased severity of acute GVHD across all grades (P =.005). Based on the Kaplan-Meier estimate, the probability of grade II-IV acute GVHD in the tacrolimus group (56%) was significantly lower than in the CSP group (74%; P =.0002). Use of glucocorticoids for the management of GVHD was significantly lower with tacrolimus than with CSP (65% vs 81%, respectively; P =. 019). The number of patients requiring dialysis in the first 100 days was similar (tacrolimus, 9; CSP, 8). Overall and relapse-free survival rates for the tacrolimus and CSP arms at 2 years was 54% versus 50% (P =.46) and 47% versus 42% (P =.58), respectively. The combination of tacrolimus and MTX after unrelated donor marrow transplantation significantly decreased the risk for acute GVHD than did the combination of CSP and MTX, with no significant increase in toxicity, infections, or leukemia relapse.
Collapse
|
34
|
Adlercreutz H, Mazur W, Bartels P, Elomaa V, Watanabe S, Wähälä K, Landström M, Lundin E, Bergh A, Damber JE, Aman P, Widmark A, Johansson A, Zhang JX, Hallmans G. Phytoestrogens and prostate disease. J Nutr 2000; 130:658S-9S. [PMID: 10702603 DOI: 10.1093/jn/130.3.658s] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
35
|
Horowitz MM, Przepiorka D, Bartels P, Buell DN, Zhang MJ, Fitzsimmons WE, Erdman J, Huang C, Hodosh E, Maher R, Wingard JR. Tacrolimus vs. cyclosporine immunosuppression: results in advanced-stage disease compared with historical controls treated exclusively with cyclosporine. Biol Blood Marrow Transplant 1999; 5:180-6. [PMID: 10392964 DOI: 10.1053/bbmt.1999.v5.pm10392964] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A phase HI comparative trial of tacrolimus- vs. cyclosporine-based graft-vs.-host disease (GVHD) prophylaxis for human leukocyte antigen (HLA)-identical sibling bone marrow transplantation showed less GVHD but poorer survival in the tacrolimus arm. To test the comparability of the two treatment arms with respect to baseline survival prognosis, a matched control study using exclusively cyclosporine-treated patients from the International Bone Marrow Transplant Registry (IBMTR) database was performed. Controls were matched (2:1) based on age (within 5 years), disease, and pretransplant disease status. Two-year survival for tacrolimus-treated clinical trial patients was similar to that of their cyclosporine-treated matched controls (27 and 24%, respectively), and 2-year survival of the cyclosporine-treated clinical trial patients was similar to that of their cyclosporine-treated matched IBMTR controls (42 and 45%, respectively). Consistent with the clinical trial results, the cyclosporine-treated IBMTR controls matched to the tacrolimus group had significantly poorer 2-year survival than the cyclosporine-treated IBMTR controls matched to the cyclosporine group (24 and 45%, respectively; p < 0.01). No significant difference was seen in GVHD between the cyclosporine-treated clinical trial patients and their matched controls; however, the tacrolimus-treated clinical trial patients had significantly less GVHD than their cyclosporine-treated IBMTR controls (p < 0.01). These results support the hypothesis that the survival difference in the phase III trial resulted from an imbalance in the underlying risk factors for death in the two groups rather than from the randomized immunosuppressive regimen.
Collapse
|
36
|
Smith R, Lubbe K, Bartels P, Godke R. Evaluating in vitro maturation time and in vitro fertilization rate of African buffalo (Syncerus caffer) oocytes. Theriogenology 1999. [DOI: 10.1016/s0093-691x(99)91853-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
37
|
Meintjes M, Bezuidenhout C, Bartels P, Visser DS, Meintjes J, Loskutoff NM, Fourie FL, Barry DM, Godke RA. In vitro maturation and fertilization of oocytes recovered from free-ranging Burchell's zebra (Equus burchelli) and Hartmann's zebra (Equus zebra hartmannae). J Zoo Wildl Med 1997; 28:251-9. [PMID: 9365936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A noninvasive repeatable method to harvest oocytes for in vitro fertilization (IVF) could potentially be used to assist reproduction in endangered equid species. The objectives of this study were to evaluate a specific transvaginal ultrasound-guided oocyte recovery procedure for use in zebra mares and the general applicability of IVF procedures in zebra. Ovaries were collected from Burchell's zebra (Equus burchelli) and Hartmann's zebra (Equus zebra hartmannae) mares at routine culling for Expt. I. Of the 144 oocytes recovered from these ovaries, 70% were of excellent quality. No significant difference in oocyte quality was found between the two zebra species. Zona drilling was performed on in vitro-matured oocytes prior to IVF. Epididymal sperm from culled Burchell's zebra stallions were used for IVF. The sperm either were exposed to calcium ionophore or were not treated and served as a control. In vitro fertilized oocytes were then co-cultured with zebra granulosa cells (ZGC) or with bovine oviduct cells (BOC) for up to 8 days. Overall, a 38% cleavage rate was obtained with 16% of sperm-exposed oocytes developing to the morula or blastocyst stage. All of the embryos that developed to at least the morula stage were cultured on BOC; whereas, none of those cultured on ZGC reached the morula stage during the same interval. Cleavage rates of oocytes inseminated with ionophore-treated or with control sperm were not significantly different, suggesting that ionophore treatment of epididymal sperm for IVF in these zebra species may be redundant. In Expt. II, 10 transvaginal ultrasound-guided oocyte aspiration procedures on five captive Burchell's zebra mares recovered a total of 33 oocytes (6.6 oocytes/female) of which 94% were considered viable. This approach may be an attractive means of producing gametes for assisted reproduction in endangered species. Furthermore, results from this study indicate that IVF may become a means of producing offspring from zebra and other equid species in the future.
Collapse
|
38
|
Elledge RM, Clark GM, Hon J, Thant M, Belt R, Maguire YP, Brown J, Bartels P, Von Hoff DD. Rapid in vitro assay for predicting response to fluorouracil in patients with metastatic breast cancer. J Clin Oncol 1995; 13:419-23. [PMID: 7844603 DOI: 10.1200/jco.1995.13.2.419] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
PURPOSE To determine if a rapid 3H-uridine uptake assay using breast tumor cells from biopsy specimens could predict clinical response to fluorouracil (5FU) in patients with metastatic breast cancer. PATIENTS AND METHODS A double-blind prospective study was conducted of 60 patients with measurable, metastatic breast cancer who had failed to respond to at least one prior chemotherapy regimen. Patients received 5FU 300 mg/m2/d by continuous infusion and were monitored for response. Tumor cells from biopsy specimens were grown in microwells and exposed for 3 days to 0.1, 1.0, 10.0, and 100.00 micrograms/mL of 5FU on strips coated with drug and extracellular matrix. Cells were pulsed with 3H-uridine overnight. Incorporated radioactivity was compared for wells with and without drug. Results were available 4 days from specimen submission. RESULTS Of 45 eligible patients, 11 (24%) were not assessable in vitro. Nine patients were assessable in vitro, but not clinically. Of the remaining 25 patients, who were assessable both clinically and in vitro, there was one complete response (CR), five partial responses (PRs), five cases of stable disease, and 14 cases of progressive disease, for an objective response rate of 24%. Response in vitro was significantly correlated with clinical response (P = .002). Of six clinical responders, five also responded in vitro, for an assay sensitivity of 83%. Of 19 nonresponders, 17 were nonresponders in vitro, for a specificity of 89%. The positive predictive value of the test was 71% (five of seven), and the negative predictive value was 94% (17 of 18). CONCLUSION Results of an in vitro assay were significantly correlated with clinical response in patients with metastatic breast cancer treated with continuous infusion 5FU.
Collapse
|
39
|
Loskutoff N, Bartels P, Meintjes M, Godke R, Schiewe M. Assisted reproductive technology in nondomestic ungulates: A model approach to preserving and managing genetic diversity. Theriogenology 1995. [DOI: 10.1016/0093-691x(94)00005-f] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
40
|
Bezuidenhout C, le R. Fourie F, Meintjes M, Bornman M, Bartels P, Godke R. Comparative epididymal sperm cell motility of african ungulate and equid game species stored at 4 °C. Theriogenology 1995. [DOI: 10.1016/0093-691x(95)92321-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
41
|
Shaw D, Kidson A, van Schalkwyk J, Bartels P, Loskutoff N, Bezuidenhout C, Rogers P, Barry D, Lishman A. In-vitro production of african buffalo (Syncerus caffer) embryos derived from follicular oocytes and epididymal sperm. Theriogenology 1995. [DOI: 10.1016/0093-691x(95)92476-p] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
42
|
Duffy FH, Jones K, Bartels P, McAnulty G, Albert M. Unrestricted principal components analysis of brain electrical activity: issues of data dimensionality, artifact, and utility. Brain Topogr 1992; 4:291-307. [PMID: 1510873 DOI: 10.1007/bf01135567] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Principal components analysis (PCA) was performed on the 1536 spectral and 2944 evoked potential (EP) variables generated by neurophysiologic paradigms including flash VER, click AER, and eyes open and closed spectral EEG from 202 healthy subjects aged 30 to 80. In each case data dimensionality of 1500 to 3000 was substantially reduced using PCA by magnitudes of 20 to over 200. Just 20 PCA factors accounted for 70% to 85% of the variance. Visual inspection of the topographic distribution of factor loading scores revealed complex loadings across multiple data dimensions (time-space and frequency-space). Forty-two non-artifactual factors were successful in classifying age, gender, and a separate group of 60 demented patients by linear discriminant analysis. Discrimination of age and gender primarily involved EP derived factors, whereas dementia primarily involved EEG derived factors. Thirty-eight artifactual factors were identified which, alone, could not discriminate age but were relatively successful in discriminating gender and dementia. The need to parsimoniously develop real neurophysiologic measures and to objectively exclude artifact are discussed. Unrestricted PCA is suggested as a step in this direction.
Collapse
|
43
|
Duffy FH, Jones K, Bartels P, Albert M, McAnulty GB, Als H. Quantified neurophysiology with mapping: statistical inference, exploratory and confirmatory data analysis. Brain Topogr 1990; 3:3-12. [PMID: 2094310 DOI: 10.1007/bf01128856] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Topographic mapping of brain electrical activity has become a commonly used method in the clinical as well as research laboratory. To enhance analytic power and accuracy, mapping applications often involve statistical paradigms for the detection of abnormality or difference. Because mapping studies involve many measurements and variables, the appearance of a large data dimensionality may be created. If abnormality is sought by statistical mapping procedures and if the many variables are uncorrelated, certain positive findings could be attributable to chance. To protect against this undesirable possibility we advocate the replication of initial findings on independent data sets. Statistical difference attributable to chance will not replicate, whereas real difference will reproduce. Clinical studies must, therefore, provide for repeat measurements and research studies must involve analysis of second populations. Furthermore, Principal Components Analysis can be employed to demonstrate that variables derived from mapping studies are highly intercorrelated and data dimensionality substantially less than the total number of variables initially created. This reduces the likelihood of capitalization on chance. The need to constrain alpha levels is not necessary when dimensionality is low and/or a second data set is available. When only one data set is available in research applications, techniques such as the Bonferroni correction, the "leave-one-out" method, and Descriptive Data Analysis (DDA) are available. These techniques are discussed, clinical and research examples are given, and differences between Exploratory (EDA) and Confirmatory Data Analysis (EDA) are reviewed.
Collapse
|
44
|
Bartels P, O'Callaghan WG, Peyton R, Sethi G, Maley T. Metastatic liposarcoma of the right ventricle with outflow tract obstruction: restrictive pathophysiology predicts poor surgical outcome. Am Heart J 1988; 115:696-8. [PMID: 3344669 DOI: 10.1016/0002-8703(88)90828-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
45
|
Lester A, Stilbo I, Bartels P, Bruun B. Value of CSF lactate in the differential diagnosis between bacterial meningitis and other diseases with meningeal involvement. ACTA PATHOLOGICA, MICROBIOLOGICA, ET IMMUNOLOGICA SCANDINAVICA. SECTION B, MICROBIOLOGY 1985; 93:21-5. [PMID: 3984742 DOI: 10.1111/j.1699-0463.1985.tb02846.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Lactate concentrations in the cerebrospinal fluid of 104 patients were determined by the Monotest Lactate Kit. Lactate values were found higher in cases of bacterial meningitis than in patients not suffering from acute CNS disorders. Elevated lactate levels were also found in patients suffering from aseptic meningitis, septicemia, CNS trauma and cerebrovascular accidents, seizures and diabetes mellitus. The highest levels were found in cases of bacterial meningitis, but there was considerable overlapping between the groups. CSF lactate thus appears to have limited diagnostic value in the differential diagnosis between bacterial meningitis and other diseases with meningeal involvement.
Collapse
|
46
|
Bruun B, Stilbo I, Bartels P. Value of pleural lactate in the differential diagnosis between empyema and non-bacterial pleural effusions. ACTA PATHOLOGICA, MICROBIOLOGICA, ET IMMUNOLOGICA SCANDINAVICA. SECTION B, MICROBIOLOGY 1984; 92:85-8. [PMID: 6730971 DOI: 10.1111/j.1699-0463.1984.tb02799.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Lactate concentrations in the pleural fluid of 50 patients were determined by the Monotest Lactate Kit. Lactate values were found higher in bacterial pleural infections than in cases of hydrothorax. Elevated levels were also found in most cases of histologically confirmed cases of pleural neoplasms and in some cases of non-bacterial pleuritis exsudativa . The highest levels were found in cases of empyema, but there was considerable overlapping between the groups. Pleural lactate thus appears to have little diagnostic value in the differential diagnosis between empyema and non-bacterial pleural effusions.
Collapse
|
47
|
Sestoft L, Folke M, Kristensen LO, Gammeltoft S, Bartels P. The effect of fructose on potassium ion movements across the cell membrane in liver [proceedings]. Biochem Soc Trans 1979; 7:204-6. [PMID: 220114 DOI: 10.1042/bst0070204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
48
|
Bartels P, Sestoft L. [Ketogenesis--physiological and pathological aspects]. Ugeskr Laeger 1978; 140:242-3. [PMID: 416534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
49
|
Haest CW, de Gier J, den Kamp JA OP, Bartels P, van Deenen LL. Chages in permeability of Staphylococcus aureus and derived liposomes with varying lipid composition. BIOCHIMICA ET BIOPHYSICA ACTA 1972; 255:720-33. [PMID: 5020221 DOI: 10.1016/0005-2736(72)90385-9] [Citation(s) in RCA: 102] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
50
|
Bartels P. Die Indikationen zur Splenektomie und die post-operative Überlebensrate. J Small Anim Pract 1969. [DOI: 10.1111/j.1748-5827.1969.tb04019.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|