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R Knüchel

Publications and source records attributed to R Knüchel.

At least 19 recordsLinked to original sources
PubMed2001

Protoporphyrin IX distribution following local application of 5-aminolevulinic acid and its esterified derivatives in the tissue layers of the normal rat colon.

Photodynamic diagnosis and especially therapy after sensitization with 5-aminolevulinic acid (ALA) is hampered by limitations of uptake and distribution of ALA due to its hydrophilic nature. Chemical modification of ALA into its more lipophilic esters seems to be promising to overcome these problems. The aim of the present study was to investigate the comparative kinetics of protoporphyrin IX (PPIX) fluorescence in rat colonic tissue after topical application of ALA and its esterified derivatives, ALA-hexylester (h-ALA), ALA-methylester (m-ALA) and ALA-benzylester (b-ALA). Fluorescence intensity induced by PPIX in normal colonic tissue was quantified using fluorescence microscopy at 1, 2, 4, 6 and 8 h after sensitization. Mucosa exhibited higher fluorescence levels compared to the underlying submucosa or smooth muscle. Peak fluorescence intensities were seen 4 h after local sensitization with 86.0 mol ml(-1) ALA (513 +/- 0.57 counts per pixel), 6.6 mol ml(-1) m-ALA (508 +/- 35.50) and 4.8 mol ml(-1) h-ALA (532 +/- 128.80), and 6 h after sensitization with 4.6 mol ml(-1) b-ALA (468 +/- 190.27). A 13-18 times lower concentration of ALA esters was required for fluorescence intensities reached with ALA alone. A similar degree of the fluorescence ratio between mucosa and muscularis (5-6:1) was detected for ALA and its derivatives. The time point of the maximum value of this ratio was consistent with peak fluorescence levels for ALA and each ALA-ester. The clinical feasibility and the advantages of topical ALA ester-based fluorescence for detection of malignant and premalignant lesions need further investigations.

Aminolevulinic Acid↗
PubMed2001

Expression of the p53 and Maspin protein in primary prostate cancer: correlation with clinical features.

The serine protease inhibitor Maspin has been reported to inhibit the invasiveness and motility of prostate cancer tumor cells. Additionally, a p53-dependent regulatory pathway of Maspin in prostate cancer cell lines has been indicated. The first aim of our study was to determine the prognostic value of Maspin protein expression for the recurrence-free survival of patients undergoing radical prostatectomy for the treatment of clinically localized prostate cancer. Secondly, Maspin expression was correlated to p53 protein expression in order to gain additional information on a possible and previously suggested regulatory influence of the wild-type p53 protein on the Maspin protein expression. Tumor specimens obtained from 84 patients undergoing radical prostatectomy for localized prostate cancer were investigated for the expression of the Maspin and p53 protein by an immunohistochemic approach. Maspin protein expression was correlated with further patients' and tumor characteristics such as tumor stage, histologic grading, regional lymph node status, p53 protein expression and recurrence-free survival of the patients following radical prostatectomy. After a median follow-up of 64 months (24-197 months), 23 of 40 patients (58%) with a negative or decreased Maspin expression (group 1) developed local recurrence or systemic tumor progression in contrast to 8 of 44 patients (18%) with a retained expression of the Maspin protein (group 2) (p = 0.02; log-rank test). The median recurrence-free survival following radical prostatectomy was 26 months (12-37 months) for group 1 patients and 41 months (5-134 months) for patients from group 2 (p = 0.04). A positive immunohistochemic staining reaction for the p53 protein was significantly correlated with a decreased expression of the Maspin protein (p = 0.015; Spearman correlation coefficient). Additionally, loss of Maspin protein expression was correlated to higher tumor stages (p = 0.002) and an increasing histologic dedifferentiation (p = 0.03). This is the first study to indicate that Maspin protein possibly functions as a clinically relevant inhibitor of tumor progression, preventing the local invasiveness and further systemic progression of prostate cancer. Our investigation delivers first hints for a p53-dependent regulatory pathway of the Maspin protein in human prostate cancer.

Adenocarcinoma↗
PubMed2001

[Endoscopic fluorescence diagnosis of esophageal carcinoma after sensitization with 5-aminolevulinic acid].

BACKGROUND: Barrett's esophagus is a complication of gastroesophageal reflux disease (GERD) characterized by specialized columnar epithelium that contains goblet cells and replaces the squamous epithelium of the distal esophagus. It is found in about 10% of patients with symptomatic reflux disease and more importantly has been associated with the development of esophageal cancer. Adenocarcinoma arises from dysplasia, which is usually not visible during routine endoscopy, therefore extensive random sampling of the entire Barrett's segment should be performed with biopsies in the 4 quadrants every 1 to 2 cm and of any macroscopic abnormality. CASE REPORT: We report the history of a 60-year-old man who was admitted to hospital because of an ulcer in Barrett's esophagus not healing despite conservative treatment. He has suffered from gastroesophageal reflux disease for more than 30 years and an antireflux surgical procedure had not resulted in regression of Barrett's esophagus. However, close surveillance could not reveal any dysplastic or malignant lesion. Endoscopic fluorescence detection (EFD) after sensitization with 30 mg/kg 5-aminolevulinic acid (5-ALA) in this patient demonstrated a selective red fluorescence in a macroscopically normal appearing area near the already known ulcer. Biopsies from this fluorescent area showed an adenocarcinoma. Esophagectomy confirmed the presence of intramucosal adenocarcinoma without lymph node metastases.

Adenocarcinoma↗
PubMed2001

Endoscopic detection of transitional cell carcinoma with 5-aminolevulinic acid: results of 1012 fluorescence endoscopies.

OBJECTIVES: The initial encouraging results using 5-aminolevulinic acid (5-ALA) induced fluorescence endoscopy (AFE) have promised a procedure with an outstanding sensitivity for the detection of early stage bladder cancer. Summarized here is our clinical experience and data comprising 1012 fluorescence endoscopies. METHODS: Two hours, 30 minutes before endoscopy, 1.5 g 5-ALA dissolved in 50 mL of 5.7% sodium monohydrogen phosphate was instilled in patients intravesically. Before AFE, all patients underwent white light endoscopy, and a bladder washing cytologic specimen was obtained. A special light source provided blue light (375 to 440 nm) for fluorescence excitation. Suspicious sites were identified by their red fluorescence contrasting against backscattered blue light when observed through the long pass filter (445 nm) integrated into the telescope eyepiece. RESULTS: Two thousand four hundred seventy-five specimens were obtained (2.4 biopsies per AFE). In 552 AFEs (54.5%), neoplastic urothelial lesions were detected, in 34.2% only because of their positive fluorescence; 38.7% of these additionally detected neoplastic foci had poorly differentiated histologic features. CONCLUSIONS: AFE has proved to be a clinically feasible procedure with an outstanding detection rate for flat, urothelial, high-risk lesions.

Administration, Intravesical↗
PubMed2001

Autofluorescence imaging to optimize 5-ALA-induced fluorescence endoscopy of bladder carcinoma.

OBJECTIVES: To design an optical system for detecting autofluorescence (AF) of bladder tumors and to determine the success of reducing the false-positive rate of 5-aminolevulinic acid-induced fluorescence endoscopy (AFE). AFE provides significantly higher sensitivity in detecting and localizing bladder carcinoma compared with white light endoscopy. The specificity of AFE is equivalent to white light endoscopy, mostly because of the false-positive fluorescence of chronic cystitis lesions. Laser-induced spectral autofluorescence detection is also an efficient method in the diagnosis of bladder carcinoma. METHODS: Bladder tissue was excited to AF using the D-Light (375 to 440 nm) after regular AFE with detection of fluorescence-positive areas. The optical image was produced using a special RGB camera. Biopsies were taken from AFE-positive areas, the peritumoral edges, and normal bladder mucosa. The AF images of the suspicious areas were compared with the AFE images and the histologic results. RESULTS: A total of 43 biopsies were histologically examined (24 benign and 19 neoplastic). AF imaging showed contrast differences between papillary tumors, flat lesions, and normal mucosa. The combination of AFE with AF raised the specificity of AFE alone from 67% to 88%. CONCLUSIONS: AF imaging is possible. The value of the method in reducing the false-positive rate of the highly sensitive AFE needs to be validated with higher numbers. The combination of AF with AFE had a 20% higher specificity than AFE alone in our study.

Administration, Intravesical↗
PubMed2001

[Surveillance of patients with Barrett's esophagus].

Barrett's esophagus is a major complication of gastroesophageal reflux disease and is associated with 30-125 fold increased risk of developing carcinoma. Because of the rising incidence of esophageal adenocarcinoma the malignant potential of Barrett's esophagus has been generally recognized. The definition of Barrett's esophagus has evolved over the last decades. It is now accepted that "Long-Barrett-Segment" (LBS) is used when intestinal-type epithelium, characterized by the presence of goblet cells, is detected in the distal esophagus > 3 cm in length. The term "Short-Barrett-Segment" (SBS) is defined by intestinal metaplasia detection < 3 cm in length in the distal esophagus. Recently, there has been focus on microscopic Barrett's esophagus, so called "Ultra-Short-Barrett's esophagus", with histological evidence of intestinal metaplasia without endoscopic appearance. The most significant predictor of the risk of malignancy in patients with Barrett's esophagus is the presence of dysplasia. Guidelines for surveillance are based on the diagnosis of dysplastic lesions. New methods (e. g. Methylene blue staining, endoscopic fluorescence detection, OCT) to improve the recognition of Barrett's esophagus and especially enhance the detection of premalignant and malignant lesions are under evaluation. So far, the standard biopsy protocol for patients with LBS includes biopsies in the 4 quadrants every 1-2 cm, whereas the appropriate surveillance intervals are dependent on the grade of dysplasia. Whether surveillance in patients with SBS has to be similar to that in patients with LBS is unclear and needs further evaluation.

Adenocarcinoma↗
PubMed2001

Quantification of 5-aminolevulinic acid induced fluorescence improves the specificity of bladder cancer detection.

PURPOSE: 5-Aminolevulinic acid induced fluorescence endoscopy has outstanding sensitivity for detecting early stage bladder cancer. Nevertheless, a third of the lesions that show specific fluorescence are histologically benign. We decreased the false-positive rate of 5-aminolevulinic acid induced fluorescence endoscopy by incorporating protoporphyrin IX fluorescence quantification into the standard cystoscopy procedure. MATERIALS AND METHODS: In 25 cases (53 biopsies) of a history of or suspicion for bladder cancer 5-aminolevulinic acid induced fluorescence endoscopy and fluorescence image quantification were performed. For fluorescence image quantification images obtained with a target integrating color charge-coupled device camera were digitized and stored in a personal computer. Red-to-blue ratios were calculated from fluorescence positive lesions and results were correlated with hematoxylin and eosin histology. RESULTS: Malignant fluorescence positive lesions showed significantly stronger fluorescence intensity than fluorescing lesions with benign histology. A threshold was established that decreased the false-positive rate by 30% without affecting sensitivity. CONCLUSIONS: Fluorescence image quantification is a new endoscopic method for objectively selecting multicolor fluorescence bladder lesion images for biopsy. It has the potential of eliminating human error by different surgeons with variable experience in fluorescence endoscopy.

Adult↗
PubMed2000

High-dose-rate brachytherapy: dose escalation in three-dimensional miniorgans of the human bronchial wall.

PURPOSE: High-dose-rate (HDR) brachytherapy of human lung cancer is well established, however fractionation schemes and dosages are based mainly on experience. The aim of this investigation was to study the effects of different doses of HDR iridium-192 on normal human bronchial epithelium in three-dimensional miniorgans of the human bronchial wall. METHODS AND MATERIALS: Forty-eight biopsies from normal bronchi were cultivated for 14 days and exposed at random to different doses of HDR iridium 192 (0 Gy, 30 Gy, 45 Gy, 60 Gy, or 75 Gy). Cell viability was assessed immediately after irradiation, after 4 or 18 days by fluorescent staining, and cell damage of the culture was analyzed by light microscopy. Lactate dehydrogenase (LDH) was measured in the supernatant for 4 days. RESULTS: There was no histologically apparent tissue damage regardless of the irradiation dose. The number of nonvital cells increased in irradiated miniorgans depending on the dose used (p < 0. 05 at 75 Gy). This effect occurred early and was less pronounced with time. LDH measurements showed an increase only in the first 24 hours. CONCLUSIONS: Our results confirm that normal bronchial epithelium has a high tolerance to early epithelial damage by irradiation. This model of human bronchial miniorgans is useful for further studies of the effects of irradiation on human bronchi.

Brachytherapy↗
PubMed2000

Identification of a new missense mutation (Gly95Glu) in a highly conserved codon within the high-mobility group box of the sex-determining region Y gene: report on a 46,XY female with gonadal dysgenesis and yolk-sac tumor.

Leydig cells and Sertoli cells of the testes produce hormones that cause male differentiation, if receptors are present. The Y chromosomal SRY gene (sex determining Region Y gene) acts as TDF and is required for regular male sex determination. SRY represents a transcription factor belonging to the superfamily of genes sharing the HMG-box motif(high-mobility group-box), which acts as DNA binding region. Here, we describe a nonmosaic XY sex-reversed female with pure gonadal dysgenesis (46,XY karyotype, completely female external genitalia, normal Müllerian ducts, absence of Wolffian ducts, streak gonads) who harbored a yolk-sac tumor and was referred for the assessment of primary amenorrhea. Using genomic PCR analysis, a 423-bp PCR product, encompassing the HMG-box of the SRY gene, was amplified from the proposita, her father, and her three brothers, whereas no band was visible in the patient's mother and her three sisters. The PCR products were sequenced for mutations subsequently. A new de novo missense mutation within the HMG-box of the SRY gene was discovered in the proposita. A G is replaced by an A in codon 95 at position +284, resulting in the replacement of the nonpolar aminoacid glycine by the polar amino acid glutamate. The glycine at codon 95 is highly conserved between the family of HMG-box proteins and between species. This point mutation has not been described earlier and brings the total number of SRY mutations described so far to 36, each mutation being unique. This mutation was not detected in the patient's father and her male siblings. The present data provide further evidence to support the functional importance of the putative DNA binding activity of the SRY HMG-box domain.

Adult↗
PubMed1999

The need for microdissectional tumor cell preparation during the molecular genetic analysis of prostate cancer.

For clinically localized prostate cancer, recent studies strongly indicate that the determination of p53 inactivation allows the identification of a highly aggressive subgroup of prostatic tumors associated with decreased recurrence-free and long-term survival following radical prostatectomy. However, several questions regarding the determination of p53 alterations in prostate cancer, such as the poor correlation between immunohistochemistry and molecular genetic analysis, remain to be clarified. On the DNA level, p53 gene alterations have been identified in only up to 64% of tumors exhibiting immunohistochemically detected overexpression of the p53 oncoprotein. This discrepancy can be explained either by the genetic microheterogeneity of prostate cancer or by stabilization of the wild-type protein due to posttranslational events. In the present study we tried to determine the concordance between an immunohistochemically detected p53 overexpression and the result of molecular genetic analysis. Therefore, tumor tissue obtained by microdissection from 40 prostate cancer specimens was subjected to DNA-sequence analysis. Microdissection was based either only on histopathologic criteria or on the result of the immunohistochemical staining reaction. In 8 of 14 (57%) tumors a positive immunohistochemical reaction could be confirmed by DNA sequencing, which revealed a missense point mutation at the p53 gene locus, mainly in the form of G-->A transversion in exon 5 of the p53 gene. Following the micropreparation of tumor cells exhibiting p53 oncoprotein overexpression, missense point mutation could be detected in an additional 4 cases. Following a microscopically guided tumor cell dissection according to the result of immunohistochemistry, DNA sequencing confirmed an immunohistochemically detected p53 overexpression in 86% of cases investigated. This result indicates that a microdissectional tumor cell preparation is recommended for molecular genetic analysis of histologically heterogeneous tissue specimens such as prostate cancer and should be performed according to and in addition to the result of immunohistochemistry when an immunohistochemical approach is available.

Adenocarcinoma↗
PubMed1999

Endoscopic fluorescence detection of dysplasia in patients with Barrett's esophagus, ulcerative colitis, or adenomatous polyps after 5-aminolevulinic acid-induced protoporphyrin IX sensitization.

BACKGROUND: Surveillance of patients with Barrett's esophagus or ulcerative colitis for dysplasia is confined to biopsy specimens taken randomly during endoscopy because dysplasia remains undetectable by visual inspection. We attempted to visualize dysplastic tissue during endoscopy after sensitization with 5-aminolevulinic acid (5-ALA) leading to accumulation and formation of protoporphyrin IX and induction of characteristic red fluorescence of the latter substance using blue light illumination. METHODS: Six patients with histologically proven low- or high-grade dysplasia (Barrett's esophagus 2, ulcerative colitis 1, Billroth-II stomach 1, rectal polyps 2) were treated with oral administration of different concentrations of 5-ALA (10 to 20 mg/kg) or by local instillation of 3 gm 5-ALA in the rectum. Endoscopic fluorescence detection was performed 1 to 6 hours after sensitization using a blue light source and compared with conventional white light endoscopy. Biopsies of fluorescent and nonfluorescent areas were compared with histologic findings. RESULTS: Normal duodenal mucosa and squamous epithelium showed more intense 5-ALA-induced background red fluorescence compared with normal mucosa in the stomach or Barrett's mucosa. Histologically, dysplasia was exclusively found in areas with red fluorescence. False-positive fluorescence was associated with microscopic inflammation of the mucosa or feces in the colon. CONCLUSIONS: 5-ALA-induced protoporphyrin IX fluorescence may be useful in the detection of dysplasia in the gastrointestinal tract by enhancement of endoscopic surveillance of patients at a high risk for dysplasia.

Adenomatous Polyps↗
PubMed1999

Predictive value of decreased p27Kip1 protein expression for the recurrence-free and long-term survival of prostate cancer patients.

The p27Kip1 gene has been identified as inductor of cell cycle arrest at the G1 checkpoint to prevent entry of somatic cells into the S phase of the cell cycle when substantial DNA damage has occurred. It has been suggested that decreased expression of the p27Kip1 protein may contribute to the development of human malignancies due to loss of critical antiproliferative mechanisms. In the present study, 95 specimens (T1-T4) from 95 randomly selected patients undergoing radical prostatectomy at the Urological Department of Hannover University (82 patients) as well as in the Josef Hospital Regensburg (13 patients) between 1981 and 1992 for whom tissue blocks for immunohistochemical investigation were available, were investigated for different biological and clinical characteristics as possible predictors for recurrence-free and long-term survival: age, depth of tumour infiltration, histological grade, lymph node status, as well as decreased expression of the p27Kip1 protein. After a median follow-up up of 56 months (24-151 months), seven of 21 (33%) patients (Group 1) with loss of p27Kip1 protein expression or a relative amount of <10% of positively stained tumour cells developed recurrent disease in contrast to 17 of 74 (23%) patients (Group 2) with retained p27Kip1 protein expression (> or =10% of positively stained tumour cells). The median recurrence-free survival was 14 months (5-40 months) for patients from Group 1 and 31 months (7-133 months) for Group 2 patients (P = 0.02). In multivariate analysis, loss of p27Kip1 protein expression was identified as the only independent prognostic parameter for recurrence-free survival. In contrast, neither the univariate nor the multivariate analysis showed a correlation between loss of p27Kip1 protein expression and the long-term survival of the patients. Prospective studies are urgently needed to confirm the independent prognostic value of decreased p27Kip1 protein expression together with overexpression of the p53 tumour suppressor protein in patients with localized prostate cancer. The availability of more refined prognostically important biological variables in addition to established prognostic factors like tumour stage or Gleason score might help decision making in patients at high risk for the development of local recurrence or systemic tumour progression.

Adenocarcinoma↗
PubMed1998

Cytokine repertoire during maturation of monocytes to macrophages within spheroids of malignant and non-malignant urothelial cell lines.

Terminal maturation of human blood monocytes to macrophages (MAC) in vivo is believed to be important for the morphology, antigen expression and functional activity of the resulting MAC population. This process is modulated by the specific tissue micro-environment to which blood monocytes migrate upon leaving the vasculature. Tumor-associated macrophages (TAM) are a special type of MAC, and little is known about the modulating capacity of the tumor environment on monocyte-to-MAC differentiation. By co-culturing 3-dimensional multicellular spheroids (MCS) of the urothelial-bladder-carcinoma cell lines J82 and RT4 with human monocytes/MAC we generated TAM in vitro. For comparison, monocytes/MAC were co-cultured with the non-tumorigenic urothelial cell line HCV29. The effects on monocyte differentiation were analyzed, particularly with respect to cytokine release. Monocyte maturation was modulated within the tumor spheroid dependent upon the tumor cell type. Monocytes co-cultured with MCS of the poorly differentiated J82 carcinoma spontaneously produced high amounts of IL-1beta and IL-6, but only low amounts of TNF-alpha, which could be further increased by the addition of LPS. This cytokine pattern is characteristic for monocytes and remained constant for up to 8 days in J82-MCS co-cultures. However, in RT4-MCS and HCV29-MCS co-cultures, the initial cytokine pattern changed and after 8 days corresponded well to that of MAC differentiated in vitro without tumor contact. In addition to functional parameters, we analyzed the morphology of J82-MCS-TAM and found that they displayed a monocyte-like morphology. Our data indicate that (1) tumor cells can influence monocyte-to-MAC differentiation, giving rise to TAM with monocyte-specific phenotypic properties; and (2) this capacity is dependent on the type of tumor cell.

Cell Differentiation↗
PubMed1998

[Photodynamic diagnosis of gastrointestinal precancerous lesions after sensitization with 5-aminolevulinic acid. A pilot study].

BASIC PROBLEM AND OBJECTIVE: Endoscopic diagnosis of gastrointestinal precancerous and cancerous lesions is difficult, often even impossible. This study was undertaken to find out whether premalignant or suspected malignant tumors can be diagnosed by preceding sensitization with 5-aminolaevulinic acid (ALA), which in tumors is transformed in increased amounts into photosensitizing protoporphyrin IX, the latter being recognized by its characteristic red fluorescence on exposure to blue light. PATIENTS AND METHODS: 20 patients with known mild or moderately severe dysplasias (Barrett's esophagus, n = 8; colorectal adenoma, n = 3; ulcerative colitis n = 2, and gastric polyps or mucosal changes suspicious of malignancy, n = 5. Two patients with squamous-cell carcinoma, who after radio- and chemotherapy were endoscopically free of tumor, were sensitized with different concentrations of ALA (orally: 5-30 mg/kg; or locally: 3 g in 100 ml 0.9% NaCl). Photodynamic diagnosis (PDD) took place 4-8 h after oral and ca. 1-2 h after local sensitization with blue light (D-light, Storz, Tuttlingen, Germany). RESULTS: Definite red fluorescence with demonstration of dysplasia was found in three of four patients with Barrett's esophagus. Biopies from nonfluorescent areas were free of dysplasia. Two gastric adenomas (10 mg/kg ALA with high-grade dysplasia were definitively endoscopically by their red fluorescence. In one patient mild dysplasia was found in a non-fluorescent area after radio- and chemotherapy of an esophageal carcinoma. Dysplasias were also seen in the rectal biopsy after local applications. CONCLUSIONS: PDD makes it possible for the first time to visualize precancerous lesions of the gastrointestinal tract after preceding ALA sensitization. PDD is a highly promising method for monitoring patients with gastrointestinal disease and an increased risk of cancer, and for clarifying the diagnosis of mucosal changes suspicious of malignancy.

Adenoma↗
PubMed1998

The immunohistochemical marker Ki-S2: cell cycle kinetics and tissue distribution of a novel proliferation-specific antigen.

The monoclonal antibody Ki-S2 binds to a recently characterized proliferation-specific protein, p100. To assess its distribution pattern under physiologic and pathologic conditions, we performed immunohistochemical analyses on an exhaustive spectrum of normal tissues, 624 miscellaneous solid cancers, and 95 hematologic malignancies, and compared the results with Ki-67 immunostaining on consecutive sections. In addition, Ki-S2 expression was related to the DNA content by dual parameter flow cytometric analysis in parallel with Ki-67 labeling using a human cancer cell line. Immunoreactivity was enhanced at the G1/S transition and persisted through G2 and M phase. After adequate antigen retrieval, the antibody was found to yield identical results on fresh and formalin-fixed, paraffin-embedded material. The antibody specifically labeled actively proliferating cells, which constitute a subset of the population recognized by Ki-67. In normal human tissues, Ki-S2 immunolabeling hardly ever exceeded 40% of the Ki-67+ cell fraction. Immunoreactive scores of the two antibodies exhibited a linear correlation, but statistically significant differences in the ratio of Ki-S2-positive to Ki-67-positive cells were nevertheless observed between different tissue types. In contrast, the ratio of Ki-S2 and Ki-67 immunoreactive scores varied widely in neoplastic cells and tissues, occasionally attaining a ratio of almost 1:1. This suggests that loss of growth regulatory mechanisms in malignant cells might result in an extreme reduction of the G1 phase fraction and thus in a significantly shorter doubling time. Therefore, antibody Ki-S2 is likely to allow a more precise evaluation of the cell fraction that will complete a division cycle and a more confident appraisal of the malignancy potential of a neoplastic process.

Antibodies, Monoclonal↗
PubMed1997

Analysis of cell cycle-related Ki-67 and p120 expression by flow cytometric BrdUrd-Hoechst/7AAD and immunolabeling technique.

Flow cytometric multiparameter analysis of two proliferation associated antigens, Ki-67 and p120, was combined with cell cycle kinetic analysis, achieved by continuous labeling with 5-Bromodeoxyuridine (BrdUrd), followed by staining with Hoechst 33258 and 7-Aminoactinomycin D (7AAD). Exponential and plateau phase monolayer cultures of the human bladder carcinoma cell line J82 were examined. Resting cells, characterized by their absent BrdUrd incorporation, showed no reactivity with the MIB1 antibody, which was used for the detection of the Ki-67 antigen. Proliferating cells revealed a cell cycle phase dependent Ki-67 staining intensity, which was partially related to the time period spent in G1 after mitosis. In contrast to the Ki-67 antigen expression, no decrease in p120 immunofluorescence staining intensity of non-cycling cells could be observed. We could demonstrate that a dissection of the history of cell replication, obtained by the BrdUrd/Hoechst technique combined with a simultaneous immunofluorescence staining reveals detailed information, on a single cell level, about time dependent expression of proliferation associated antigens in all cell cycle compartments.

Antigens, Neoplasm↗