Jan P. A. Baak

Prof. Dr. Jan P. A. Baak

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Research Focus & Metrics

Academic Career Length

35Years (1992-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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11 September 2012 in Histopathology
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EGEinar Gudlaugsson
Einar Gudlaugsson
ISIvar Skaland
Ivar Skaland
EJEmiel A M Janssen
Emiel A M Janssen
RSRune Smaaland
Rune Smaaland
ZSZhiming Shao
Zhiming Shao
JBJan P. A. Baak
Jan P. A. Baak

27 February 2023 in Molecules
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Journal Article
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YGYanxiong Gan
Yanxiong Gan
JBJan P. A. Baak
Jan P. A. Baak
TCTaijun Chen
Taijun Chen
HYHua Ye
Hua Ye
WLWan Liao
Wan Liao
SZShichao Zheng
Shichao Zheng
Supersaturation is a promising strategy to improve gastrointestinal absorption of poorly water-soluble drugs. Supersaturation is a metastable state and therefore dissolved drugs often quickly precipitate again. Precipitation inhibitors can prolong the metastable state. Supersaturating drug delivery systems (SDDS) are commonly formulated with precipitation inhibitors, hence the supersaturation is effectively prolonged for absorption, leading to improved bioavailability. This review summarizes the theory of and systemic insight into supersaturation, with the emphasis on biopharmaceutical aspects. Supersaturation research has developed from the generation of supersaturation (pH-shift, prodrug and SDDS) and the inhibition of precipitation (the mechanism of precipitation, the character of precipitation inhibitors and screening precipitation inhibitors). Then, the evaluation approaches to SDDS are discussed, including in vitro, in vivo and in silico studies and in vitro–in vivo correlations. In vitro aspects involve biorelevant medium, biomimetic apparatus and characterization instruments; in vivo aspects involve oral absorption, intestinal perfusion and intestinal content aspiration and in silico aspects involve molecular dynamics simulation and pharmacokinetic simulation. More physiological data of in vitro studies should be taken into account to simulate the in vivo environment. The supersaturation theory should be further completed, especially with regard to physiological conditions.

20 October 2015 in BMC Cancer
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MZMenghan Zhu
Menghan Zhu
YHYuan He
Yuan He
JBJan P. A. Baak
Jan P. A. Baak
XZXianrong Zhou
Xianrong Zhou
YQYuqing Qu
Yuqing Qu
QWQing Wang
Qing Wang
In 5–20 % of patients with cervical high-grade squamous intraepithelial lesion (HSIL), a positive margin after the loop electrosurgical excision procedure (LEEP) is associated with persistence/recurrence, but the prognostic value of other clinico-pathological factors is less clear. Among 4336 patients with HSIL who underwent an initial LEEP, 275 (6 %) had HSIL-positive margins, 37 of whom were lost to follow-up. We evaluated the remaining 238 patients. Persistence/recurrence was defined as histopathological HSIL during follow-up. The age of the patients ranged from 21 to 69 years (median: 40). The median follow-up period was 25 months (range: 6–43). Of the 238 patients, 211 (88.7 %) patients remained free of persistence/recurrence, while 27 (11.3 %) experienced persistence/recurrence. According to a univariate analysis, age (P = 0.03) and maximum specimen diameter (P = 0.043) were associated with persistence/recurrence, but number/location of involved margin sections and the pathology of the endocervical curettage were not (P > 0.10). The relative risk of the subjects (greater than or equal to 35 years ages) was 4.6 times of the subject less than 35 years, the difference was statistically significant (14 % vs. 3 %, P < 0.05). A multivariate analysis indicated that an age of 35 years or older was the only independent risk factor (OR 4.97, 95 % CI 1.14–21.62, P = 0.03). In patients with HSIL and HSIL-involved margins after an initial LEEP, age is a strong independent predictor of persistence/recurrence. Follow-up with screening cytology and/or biopsy may be considered in younger patients, whereas a secondary LEEP/hysterectomy may be considered in older patients.

7 January 2014 in PLOS ONE
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OMOk Målfrid Mangrud
Ok Målfrid Mangrud
RWRune Waalen
Rune Waalen
EGEinar Gudlaugsson
Einar Gudlaugsson
IDIngvild Dalen
Ingvild Dalen
ITIlker Tasdemir
Ilker Tasdemir
JBJan P. A. Baak
Jan P. A. Baak
European treatment guidelines of TaT1 urinary bladder urothelial carcinomas depend highly on stage and WHO1973-grade but grading reproducibility is wanting. The newer WHO2004 grading system is still debated and both systems are currently used. To compare reproducibility and prognostic value (of stage progression) of the WHO1973 and WHO2004. One hundred and ninety-three primary urothelial carcinomas were reviewed. Follow-up data were retrieved from the patient records. Kappa statistics and Harrell's C-index were used. Median follow-up was 75 months (range 1–127). 17 patients (9%) progressed, 82% of these within and 18% after 60 months. The distribution of WHO73-grades 1, 2 and 3 was 23%, 51% and 26%, interobserver agreement for each individual grade was 66% (kappa = 0.68), while for grades 1&2 versus 3 89% (kappa = 0.68). Intraobserver reproducibility was 68–63% for WHO73 and 88–89% for WHO73 as 1&2 vs.3. Progression free survival rates at 5 years were 95% (grade 1), 98% (grade 2) and 82% (grade 3) and 96% and 82% for grades 1&2 versus 3 (Hazard Ratio, HR, 5.4, p = 0.003). Using WHO2004, 62% were low grade and 38% high grade, inter-observer agreement 87% (kappa = 0.70), intraobserver reproducibility 93%, and progression free 5-year survival rates 97% and 85% (HR 6.6, p = 0.004). Positive and negative predictive values for stage progression within 5 years for the WHO73 (1&2 vs. 3) were 18% and 96%, and 15% and 97% for the WHO04. Using Harrell's C-index, none of the grading systems was prognostically superior. None of the grading systems is prognostically stronger than the others. Most importantly, inter-observer reproducibility and sensitivities for stage progression of both systems are low and need improvement for optimal treatment.

8 July 2012 in Breast Cancer Research and Treatment
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KJKristin Jonsdottir
Kristin Jonsdottir
HZHui Zhang
Hui Zhang
DJDarshni Jhagroe
Darshni Jhagroe
ISIvar Skaland
Ivar Skaland
ASAida Slewa
Aida Slewa
JBJan P. A. Baak
Jan P. A. Baak

8 December 2010 in Integrative Cancer Therapies
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HGHuiru Guo
Huiru Guo
JLJia Xiang Liu
Jia Xiang Liu
LXLing Xu
Ling Xu
TMTesfaye Madebo
Tesfaye Madebo
JBJan P. A. Baak
Jan P. A. Baak
Background: Targeted therapy (TT), chemotherapy, and traditional Chinese medicine herbal treatment (TCM) can improve the prognosis of advanced pulmonary adenocarcinoma patients. Their independent prognostic value is unknown. Objective: To study whether TCM improves survival in stage IV pulmonary adenocarcinoma patients with platinum-based chemotherapy (PBT), or combined PBT and second-line TT. Methods: Retrospective analysis of 133 fully ambulant clinical outpatients treated with PBT alone or PBT with/without second-line TT, with/without TCM. Univariate (Kaplan—Meier) and multivariable (Cox model) survival analysis were performed, using disease-specific mortality as an endpoint. Results: Gender (P = .002), TT (P < .0001), and TCM (P < .0001) had univariate prognostic value but not age, radiotherapy, or TCM syndrome differentiation (P > .10). TCM herbal treatment (P < .0001) and TT (P = .03) had multivariable independent prognostic value. TCM-treated patients (n = 103, PBT+TT+TCM+ = 62; PBT+TT−TCM+ =41) had 88% 1-year overall survival rate with median survival time (MST) of 27 months, contrasting 27% 1-year overall survival and MST of 5.0 months for non-TCM-treated (n = 30) patients. Patients with chemotherapy/TT/TCM (PBT+TT+TCM+, n = 62), TCM without TT (PBT+TT−TCM+, n = 41), or chemotherapy only (PBT+TT−TCM−, n = 30), had 1-year survival rates of 94%, 78%, and 27% respectively; for these 3 groups, respectively, MST was not reached (MST of 30.9 months), 22.6, and 5.0 months (P < .0001). Conclusions: TCM herbal treatment may improve survival of stage IV pulmonary adenocarcinoma patients treated with chemotherapy without or with second-line TT. This warrants formal phase 1 and 2 trials and ultimately properly designed prospective clinical validation trials with adequate methodology developed for data collection.