Coral communities of the remote atoll reefs in the Nansha Islands, southern South China Sea.

During the months of May and June in the year 2007, a survey was conducted regarding coral reef communities in the remote atolls (Zhubi Reef and Meiji Reef) of Nansha Islands, southern South China Sea. The goals of the survey were to: (1) for the first time, compile a scleractinian coral check-list; (2) estimate the total richness, coral cover, and growth forms of the community; and (3) describe preliminary patterns of community structure according to geomorphological units. Findings of this survey revealed a total of 120 species of scleractinia belonging to 40 genera, while the average coral cover was 21 %, ranging from less than 10 % to higher than 50 %. Branching and massive corals were also found to be the most important growth forms of the whole coral community, while Acropora, Montipora, and Porites were the three dominant genera in the overall region, with their contributions to total coral cover measuring 21, 22, and 23 %, respectively. Overall, coral communities of the Nansha Islands were in a relative healthy condition with high species diversity and coral cover. Spatial pattern of coral communities existed among various geomorphological units. Mean coral cover was highest in the patch reef within the lagoon, followed by the fore reef slope, reef flat, and lagoon slope. The greatest contributors to total coral cover were branching Acropora (45 %) in the lagoon slope, branching Montipora (44 %) in the reef flat, and massive Porites (51 %) in the patch reef. Coral cover in the fore reef revealed a greater range of genera than in other habitats. The leeward fore reef slope had higher coral cover (> 50 %) when compared with the windward slope (< 10 %). The coral communities of the inner reef flat were characterized by higher coral cover (27 %) and dominant branching Montipora corals, while lower coral cover (4 %) was dominated by Psammocora with massive growth forms on the outer reef flat. Destructive fishing and coral bleaching were two major threats to coral communities in the study area.

Intensive insulin therapy in severe acute pancreatitis: a meta-analysis and systematic review.

OBJECTIVE: To assess the effect of intensive insulin therapy on outcomes of patients with severe acute pancreatitis. METHODS: Relevant literatures cited in these electronic databases: Medline, Chinese Biomedical Literature Database, China National Knowledge Infrastructure (CNK1) database, and Excerpta Medical database (Embase) were systematically searched for randomized controlled trials (RCTs) in which intensive insulin therapy was used in severe acute pancreatitis. Length of hospitalization, acute physiology and chronic health evaluation II (APACHE II) score, incidence of complications, and adverse effects were recorded for statistical analysis. The methodological quality of the eligible studies was assessed by Jadad scale. The results were analysed by Revman 4.3 software. RESULTS: Three studies, which included a total of 118 cases, were finally reviewed. The methodological quality of the trials varied substantially In patients with severe acute pancreatitis, intensive insulin therapy was associated with shorter length of hospitalization (weighted mean difference (WMD) = -12.13, 95% confidence interval (CI) [-15.48, 8.78], p > 0.00001) and lower APACHE II score after 72 hours treatment (WMD = -3.80, 95% CI [-4.88,2. 72], p > 0.00001). One study reported insulin-related adverse event. CONCLUSION: In patients with severe acute pancreatitis, intensive insulin therapy could relieve the patient's condition earlier and shorten the length of hospitalization without serious adverse effect.

Population dose from medical exposure in Taiwan for 2008.

PURPOSE: The largest contribution to the population dose from man-made ionizing radiation sources is the medical exposure. Exposure to patients from medical examinations is of interest because it is a global indicator for the quality of radiology practice. Due to the different healthcare systems and the considerable variations in the equipment and manpower in radiology, the population dose from medical exposure varies by a large extent in different countries. This dose from different diagnostic procedures provides information that can be used to establish national reference levels. It is also useful to determine the priority in terms of dose reduction so as to optimize the protection of patients in a cost-effective manner. In the present work, the collective effective doses due to different medical modalities were estimated for the Taiwan population in 2008. METHODS: The collective effective dose from medical exposure was calculated using information on the number of procedures and the average effective dose per procedure. The frequency of procedures was extracted from the National Health Insurance (NHI) research database. The enrollment of Taiwan population in the NHI program was 99.48% in 2008. The average effective dose per procedure was derived from hospital surveys, measured data, and published results. RESULTS: Estimates of the collective effective dose were made for different medical modalities, i.e., the conventional radiography and fluoroscopy, computed tomography, interventional fluoroscopy, nuclear medicine, and dental radiography. Each modality was further divided into relevant classes by the body part or organ system. Among 23 037 031 Taiwan population in 2008, the annual examination frequencies per 1000 population were 550, 55.1, 15.6, 13.6, and 112 for the conventional radiography and fluoroscopy, computed tomography, interventional fluoroscopy, nuclear medicine, and dental radiography, respectively. The corresponding collective effective doses were 3277, 8608, 2743, 2303, and 28 man-Sv, respectively. Thus, the average effective dose per caput was 0.74 mSv, which was in the range of 0.3-1.5 mSv for the 12 European countries estimated for 2008. CONCLUSIONS: In the period from 1997 to 2008, the procedure frequency per 1000 population increased by a factor of 2.3 for computed tomography, 2.2 for interventional fluoroscopy, 1.8 for conventional radiography and fluoroscopy, and 1.5 for nuclear medicine. It demonstrated that the medical utilization of imaging facilities raised rapidly.

Chromosome assignments in man of the genes for two hexosephosphate isomerases.

Thirty-seven clones of somatic cell hybrids between human and mouse cells were examined for retention of human chromosomes and expression of human constitutive enzymes. Human glucosephosphate isomerase and chromosome F-19 were retained or lost concordantly, as were human mannosephosphate isomerase and chromosome C-7. The genes for the enzymes are thus assigned to these two chromosomes.

Frequencies of sister chromatid exchanges in heteroploid cell lines of human melanoma origin.

Sister chromatid exchange(s) (SCE) per cell and chromosome in five heteroploid cell lines and sublines of human melanoma origin were distinctly more numerous than those in the normal diploid control. The SCE per unit chromosome length was higher in stable heteroploid C32 (0.041-0.047) and C9 (0.056) than in normal diploid control. The SCE per unit chromosome length was higher in stable heteroploid C32 (0.041-0.047) and C9 (0.056) than in normal diploid control C182 (0.036), which suggested that the longer the total chromosome length of the cell genome, the higher the SCE per cell as well as per unit chromosome length. These malignant heteroploid lines had karyotypes ranging from hypodiploidy to hypotriploidy and were extremely heterogeneous in one cell line but unusually homogenous and stable in others. However, none of these properties could be correlated to the increase in SCE frequency. As compared to C32-r7, the subline C32-RO had more SCE per cell, chromosome, and unit chromosome length for the genome as well as for 9 of 11 individual chromosomes and chromosome groups. In contrast, the C32-RO specific ring marker chromosome had only 40% of the SCE of its nonring homologue in C32-r7 cells. Interestingly, C32-RO and its ring marker were less stable than C32-r7 and the nonring marker during in vitro growth. There was no noticeable difference between C32-r7 and its derivative C32-r7-nu-1, which implied that transplantation into nude mice did not alter the expression of SCE in this subline.

Karyotypic derivation of H9 cell line expressing human immunodeficiency virus susceptibility.

BACKGROUND: The T-cell lymphoma HUT78 cell line and the H9 clone of the CD4-positive HT cell line, derived from HUT78, are known to be genetically identical on the basis of allozyme (allelic isozyme) patterns and DNA fingerprinting, but the chromosome compositions of these cell lines have not been determined. The HT cell line and its H9 clone carry susceptibility to the human immunodeficiency virus (HIV). PURPOSE: The purpose of this study was to examine specific chromosome changes linking the expression of the HIV susceptibility that is unique to H9 cells by characterizing the karyotypes of the HUT78 and the H9 cell lines, by comparing chromosome differences between these lines, and by evaluating the relationships between them. METHODS: Air-dried chromosome slides were prepared, and the fast Giemsa-trypsin method was used to delineate G-bands. The numerical distribution of chromosomes from the two cell lines was determined, and complete chromosome analysis in 47 HUT78 metaphases and 21 H9 metaphases with discernible G-banding was used to specify the modal karyotypes of each cell line. RESULTS: Both cell lines had complex karyotypes that contained 47%-65% structurally modified marker chromosomes. The distribution of numbers of chromosomes in HUT78 cultures was broad. There were two distinct modal numbers of chromosomes at 42 and 43 and at 73, resulting from the presence of three actively growing sublines: two hypodiploid (1s) sublines (HUT78/1sA and HUT78/1sB) and a hypertriploid (2s) subline (HUT78/2s), respectively. HUT78/1sA and HUT78/1sB differed by five reciprocal chromosome replacements, and HUT78/2s had double copies of most of the chromosomes in 1s cells. H9 and HUT78/2s had had 21 matching markers, 10 of which were paired; contained 21 chromosomes with the same number of copies; consistently lacked eight homologous normal chromosomes; and showed close modal numbers of chromosomes at 69 and 73, respectively. CONCLUSIONS: Derivation of the 2s subline from the 1s subline by polyploidization is apparent. All lines apparently had the same progenitor cell population, and HUT78/2s represents an intermediate linking HUT78/1s to H9. IMPLICATIONS: These data should be useful for studying specific chromosome changes linking the expression of the HIV susceptibility unique to H9 cells. Karyologic studies such as those presented here can provide data (a) to clearly identify the clonal cell population of a subline, (b) to examine relationships among sublines of the same progenitor, and (c) to provide a clue that may link a subtle chromosome change to a phenotypic expression.

Correlation of in vivo malignancy with in vitro properties of human-mouse hybrid cells.

The in vivo tumorigenicity of malignant mouse-nonmalignant human somatic cell hybrids was correlated with the in vitro characteristics. The renal adenocarcinoma mouse cell line RAG and the normal, diploid human cell line Wl-38 were used as the fusion parents. Five independent RAG Wl 38 hybrid clones were tested for concanavalin A (Con A) agglutination patterns, in vitro invasiveness, and tumor formation in immunosuppressed mice. Tests on the parental lines showed that RAG cells agglutinated at much lower levels of Con A than the Wl-38 cells. RAG cells overgrew Wl-38 cells in the in vitro invasiveness assay. RAG cells readily formed tumors in untreated adult or young immunosuppressed mice, whereas the Wl-38 cells did not. The five hybrid clones were all similar, since they had Con A agglutination levels intermediate to those of both parents, though patterns were more "tumor-like", overgrew the Wl-38 cells in the invasiveness assay, and formed tumors in immunosuppressed mice.

Characteristics of cell lines established from human colorectal carcinoma.

We have characterized 14 human colorectal carcinoma cell lines established from primary and metastatic sites by us during the years 1982 to 1985. Five lines were established in fully defined ACL-4 medium and 9 in serum supplemented R10 medium. However, after establishment, cultures could be grown interchangeably in either medium. The lines grew as floating cell aggregates in ACL-4 medium, while most demonstrated substrate adherence in R10 medium. The lines had relatively long doubling times and low cloning efficiencies. Twelve were tumorigenic in athymic nude mice when injected s.c., and two grew i.p. as well. Based on culture, xenograft, and ultrastructural morphologies, the 14 lines could be subtyped as follows: 4 were well differentiated; 5 were moderately differentiated; 4 were poorly differentiated; and 1 was a mucinous carcinoma. Membrane associated antigens characteristic for gastrointestinal cells (carcinoembryonic antigen, CA 19-9, and TAG-72 antigens) were expressed by 50-71% of the lines. Lines expressing carcinoembryonic antigen and CA 19-9 actively secreted these antigens into the supernatant fluids while TAG-72 antigen was not secreted. Surprisingly, 5 of 7 of the original tumor samples tested and 13 of 14 cultured lines expressed L-dopa decarboxylase activity, which is a characteristic enzyme marker of neuroendocrine cells and tumors. In addition, one poorly differentiated cell line contained dense core granules, characteristic of endocrine secretion. Preliminary cytogenetic analyses indicated that 9 of 11 lines examined contained double minute chromosomes. In addition, 3 of the 9 lines with double minutes also had homogeneously staining regions. These findings indicate a high incidence of amplification of one or more as yet unidentified genes.

Establishment and characterization of a human adrenocortical carcinoma cell line that expresses multiple pathways of steroid biosynthesis.

We established a continuous cell line, NCI-H295, from an invasive primary adrenocortical carcinoma. The cell line was established in a fully defined medium (HITES) and later could be adapted for growth in a simple medium supplemented only with selenium, insulin, and transferrin and devoid of serum, steroids, fibroblast growth factor, and a source of exogenous cholesterol. NCI-H295 cells had a relatively long population doubling time and were tumorigenic when inoculated s.c. into athymic nude mice. The cultured cells had ultrastructural features of steroid-secreting cells and contained complex cytogenetic abnormalities including the presence of multiple marker chromosomes. Steroid analyses (radioimmunoassays and mass spectrometry), performed 7 to 9 years after culture initiation, demonstrated secretion of more than 30 steroids characteristic of adrenocortical cells. Total unconjugated steroid secretion in serum-supplemented medium was 2.83 micrograms/10(6) cells/24 h and about 4-fold less in serum-free medium. The major pathway of pregnenolone metabolism in NCI-H295 cells is androgen synthesis, with formation of dehydroepiandrosterone, androstenedione, testotesterone, and at least three sulfated androgens, as well as estrogens. In addition, formation of cortisol, corticosterone, aldosterone, and 11 beta-hydroxyandrostenidione indicated the presence of 11 beta-hydroxylase. Thus, multiple pathways of steroidogenesis are expressed by NCI-H295 cells, including formation of corticosteroids, mineralocorticoids, androgens, and estrogens. Our findings indicate the presence in NCI-H295 cells of all of the major adrenocortical enzyme systems, including 11 beta-hydroxylase, desmolase, 21 alpha-hydroxylase, 17 alpha-hydroxylase, 18-hydroxylase, lyase, sulfokinase, and aromatase. The NCI-H295 cell line should prove of value in studying the regulation, metabolic pathways, and enzymes involved in steroid formation and secretion. In addition, it may provide insights into the biology and treatment of adrenocortical carcinoma.

Characteristics of cell lines established from human gastric carcinoma.

We report the establishment and characterization of four continuous cell lines derived from human primary and metastatic gastric carcinomas, and we compare their properties with a panel of colorectal carcinoma cell lines previously established and reported by us. Our success rate in culturing gastric carcinomas was relatively low, especially from primary tumors, compared to colorectal carcinoma. These observations may reflect the relatively modest number of gastric carcinoma cell lines established (mainly from Japan), compared to the abundance of colorectal carcinoma lines established worldwide. All four gastric lines expressed the surface glycoproteins carcinoembryonic antigen and TAG-72 and three lines expressed CA 19-9. Two of the lines expressed aromatic amino acid decarboxylase but lacked other markers for neuroendocrine differentiation. All four lines were positive for vasoactive intestinal peptide receptors but lacked gastrin receptors. In addition, two lines expressed receptors for muscarinic/cholinergic receptors but not beta-adrenergic receptors. Cytogenetic evidence for gene amplification was present in the cell lines. All four lines contained varying numbers of double-minute chromosomes. One line, SNU-16, was amplified for the c-myc proto-oncogene and contained four homogeneously staining regions. While c-myc and c-erb-B-2 RNA were expressed by all lines, there was no evidence of amplification or overexpression of several other proto-oncogenes and growth factors. The multiple properties we have described in our gastric carcinoma cell lines are remarkably similar to those found in the panel of colorectal carcinoma cell lines. These properties include morphology, growth characteristics, expression of surface glycoproteins, partial expression of neuroendocrine cell markers, frequent chromosomal evidence of gene amplification, and occasional amplification of the c-myc proto-oncogene. Our four well characterized cell lines should provide useful additions to the modest number currently available for in vitro studies of gastric carcinoma.

Mass spectrometry-guided refinement of chemical energy buffers.

Biocatalytic reactions often require supplying chemical energy and phosphate groups in the form of adenosine triphosphate (ATP). Auxiliary enzymes can be used to convert a reaction by-product-adenosine diphosphate (ADP)-back to ATP. By employing real-time mass spectrometry (RTMS), one can gain an insight into inter-conversions of reactants in multi-enzyme reaction systems and optimize the reaction conditions. In this study, temporal traces of ions corresponding to adenosine monophosphate (AMP), ADP and ATP provided vital information that could be used to adjust activities of the 'buffering enzymes'. Using the RTMS results as a feedback, we also characterized a bienzymatic energy buffer that enables the recovery of ATP in the cases where it is directly hydrolysed to AMP in the main enzymatic reaction. The significance of careful selection of enzyme activities-guided by RTMS-is exemplified in the synthesis of glucose-6-phosphate by hexokinase in the presence of a buffering enzyme, pyruvate kinase. Relative activities of the two enzymes, present in the reaction mixture, influence biosynthetic reaction yields. This observation supports the conclusion that optimization of chemical energy recycling procedures is critical for the biosynthetic reaction economy.

Evidence for a multistep pathogenesis in the generation of tumorigenic cell lines from hemopoietic colonies exposed to Abelson virus in vitro.

The present studies were undertaken to investigate the ability of Abelson murine leukemia virus (A-MuLV) to transform cells derived in vitro from pluripotent hemopoietic progenitor cells of high proliferative potential. We now report that continuously growing, autonomous cell lines could be obtained from a high proportion of individually infected multilineage colonies generated in assays of spleen cells from normal adult mice if the infected cells were cocultivated for the first two to three months with irradiated NIH-3T3 cells. No lines were obtained if the 3T3 cell feeders were not initially present. Similar results were obtained when the cells exposed to virus were from multilineage colonies originating from isolated single cells obtained by replating small blast colonies. Characterization of the transformants and a number of derivative cloned sublines revealed the consistent presence of a mast cell phenotype, with some suggestion of macrophage differentiation in a few cases. All cell lines tested produced virus, showed a variable pattern of A-MuLV integration, and gave rise directly to tumors when injected subcutaneously, as shown by both Southern analysis and cytogenetic studies. The early absolute but transient dependence of these A-MuLV mast cell transformants on a fibroblast feeder suggests a multistep process in their evolution, in which the acquisition of autonomy from factors of mesenchymal cell origin may play an important role.

Polymorphic variants in human chromosome 15.

We found eight polymorphic variants in human chromosome 15 using Q, C, Q-C and Ag-NOR staining methods. These variants included brightly or dully fluorescent pericentric segments and satellites, giant satellites, increased amounts of short arm hetrochromatin (ph+) and darkly (C band-positive) or lightly (C band-negative) Giemsa-stained pericentric Q-negative segments. These staining properties indicated that the entire short arm of 15 contained at least four distinct chromatin segments: Q-negative centromeric heterochromatin, a Q-variable distal segment, a Q-negative satellite stalk, and Q-variable satellites, in that order, from proximal to distal ends. The BrdU-Hoechst 33258-stained R bands (RBH) and high resolution G subbands were also studied for karyologic characterization of chromosome 15. Most of these variants were reported also in 13, but insufficiently documented in other D and G chromosomes. Together with polymorpic pericentric fluorochromes seen in 3 and 4, Yq, and nonpathogenic t(D;Yq), the pattern of these variants can be used as karyologic fingerprints for identification of each individual and his or her cell explants both in vivo and in vitro.

Modal karyotype of human leukemia cell line, K562 (ATCC CCL 243).

The chromosome composition of the human leukemic cell line, K562, deposited at the American Type Culture Collection (ATCC) (CCL 243), was studied and further compared with those reported by other laboratories. In CCL 243, the modal karyotype had 55 normal and 14 constitutive marker chromosomes and occurred in nearly 50% of the cultured cell population. Other variant karyotypes were observed either at a low frequency in coexisting minor cell types or only once in all other analyzed metaphases. Normal chromosome #9 and the chronic myeloid leukemia (CML) specific Ph/t(9;22) were absent. It appears that karyotypes of most K562 cultures distributed world-wide are similar to each other, with the stable modal chromosome number, and therefore, the modal karyotype presented here should be useful in karyotypic identification of a cell line.

Cytogenetics of somatic cell hybrids. II. Modal karyotypes and mosaicism in mouse mutant cell lines: LM(tk-), A9, and Rag.

Modal karyotypes of mouse mutant cell lines, LM(tk-), A9, and Rag, which are frequently used as a donor line for somatic cell hybridization, are described and compared with karyotypes previously reported by other laboratories. Results are summarized as follows. Many cells (18%-38%) in each line had the same chromosome composition as the modal karyotype. Chromosome differences from the modal karyotype in some cells mainly involved one or a few chromosomes only. These differences are mostly caused by structural changes from well documented mechanisms or simple numerical changes including artifacts arising from the rupture of cells. Karyotypes of coexisting subpopulations within the same cell line can be clearly identified. Assessment of karyologic properties of a heteroploid cell population may vary considerably depending on whether it is estimated on a subpopulation or the total population as a unit. Modal karyotypes of these cell lines contained most marker chromosomes of, and a similar chromosome composition to those previously reported by other laboratories. These cell lines exhibit karyotypic constancy; thus, we believe that chromosome changes associated with clonal growth of somatic cell hybrids can be identified without ambiguity.

SK-UT-1B, a human tumorigenic diploid cell line.

SK-UT-1B (ATCC HTB 115) produced tumors 2 weeks after subcutaneous injection of 10 million cells into athymic nude mice. Karyotypic analysis at the 500-600 subband level, however, did not reveal any noticeable aberrations. This cell line therefore may represent the first example of experimentally proven human tumorigenic cells of solid tumor origin that retains the diploid karyotype in vitro indefinitely.

Intercellular karyotypic similarity in near-diploid cell lines of human tumor origins.

Intercellular karyotypic compositions were studied in seven near-diploid cultured cell populations (including six cell lines) of human colorectal and fibrosarcoma origins. Within each population, 50-88% of cells had the same cell-line-specific karyotype. In five of these seven populations, coexisting minor cell types could readily be identified, implicating the frequent occurrence of mosaicism in transformed cell lines. Nearly 90% of these cell types showed a single chromosome loss or gain from the modal cell karyotype. Parameters that may assist in the evaluation of karyotypic diversity of a transformed cell line are discussed briefly.

Karyotype consistency in human colorectal carcinoma cell lines established in vitro.

Karyotypes of nine human colorectal cell lines deposited with the ATCC were studied by trypsin-Giemsa banding. CCL 229,230,231 and 235 (Modal chromosome number, Sm, was 49, 68, 47, and 40, respectively) belong in the stable type that is characterized by karyotypes consisting mostly of normal chromosomes and stable markers. CCL 228, 234, and 238 (Sm=55,79, and 70 respectively) belong in the unstable type that has karyotypes consisting of numerous markers in addition to normal chromosomes and stable markers. The remaining intermediate type (CCL 233 and 237, Sm = 60 and 64, respectively) has karyotypic characteristics between the above two types usually with two or less unstable markers per cell. The stable markers (together with normal chromosomes) are constitutive components of a cell genome and are common to most cells within the same cultured population. Unstable markers, which generally constitute only a small portion of the total chromosome complement are the likely cause of karyotypic variations between cells and often are produced by balanced inter- or intrachromosome changes, or both. Consequently, total chromosome length per cell genome is remarkably consistent within a cell population, and karyotypes between cells, such as from four stable lines, are profoundly stable and mostly identical. Chromosome deletions and interhomologue exchanges (including isochromosomes) had the highest incidences among both stable and unstable markers. The complex markers occurred relatively infrequently. There were neither common markers nor unique chromosome breakages common to all of these established cell lines. However, chromosomes No. 7 and 1 had the highest incidence (15 and 12, respectively) of structural modifications resulting in the formation of stable markers (82 total exchanges in nine cell lines), and chromosomes No. 7 and 2 were involved at high incidence (21 and 15, respectively) in the formation of both stable and unstable markers (181 total exchanges). Moreover, No. 7 is overrepresented in eight of nine lines. The significance of chromosome changes involving No. 7 in this as well as other tumor pathotypes is briefly discussed.

DLD-1 and HCT-15 cell lines derived separately from colorectal carcinomas have totally different chromosome changes but the same genetic origin.

Aneuploid DLD-1 and HCT-15 cell lines independently derived from a colon carcinoma by two researchers lacked a common marker chromosome or a concurrent numerical change. To further look into the genetic identity of these two cell lines, we used chromosome painting with fluorescence in situ hybridization (FISH) and confirmed the G-band identification on all chromosome changes. We have also found comparable results between these two cell lines on C-/Q- polymorphic bands of several chromosomes, and electrophoretic patterns of restriction fragment-length polymorphisms (RFLPs) from eight Y-chromosome-specific DNA probes with 13 restriction enzymes. These results strongly suggest that DLD-1 and HCT-15 are identical genetically. Clearly, cell lines bearing totally unrelated changes in karotypes can be generated from the same cancer specimen.

WiDr is a derivative of another colon adenocarcinoma cell line, HT-29.

This paper documents chromosomal and isozymic evidence indicating that WiDr is a derivative of another colon adenocarcinoma cell line, HT-29, which was established in 1964. The phenotypes for seven isozymes studied were identical for all HT-29 and WiDr cell lines. The karyotypes were similar between four HT-29 cultures separated by more than 100 passages and two WiDr cultures that were studied independently in 1979 and 1985. The isozymic and karyotypic data are consistent with that described for the cell line WiDr, originally reported in 1979. Detailed karyotypic comparisons further show that cultures of WiDr possess all nine chromosomal markers found in the initial HT-29 (passage 19) cultures. However, both the higher passaged HT-29 and WiDr differ from the initial HT-29 (passage 19) because it has an additional five to eight constitutive marker chromosomes. An increase or decrease of one copy in several normal chromosomes is also noticed with more normal chromosome gains than losses. The study provides another example demonstrating the remarkable karyotypic stability within a heteroploid cell line with continued passage. It also reemphasizes the critical need for detailed karyotypic and isoenzymic studies on all cell lines in common use.