Inadequacies of self-report data for exclusion criteria detection in marihuana research: an empirical case for multi-method direct examination screening

Stringent exclusion criteria in drug abuse research are necessary to protect against methodological confounds compromising the interpretation of findings. However, reliance on self-report screening may fail to detect important exclusion variables. We compared three levels of exclusion criteria screening in a study of neurophysiological/neurocognitive sequelae of chronic marihuana use in normals. LEVEL 1 (self-report) consisted of telephone pre-screening. LEVEL 2 (also self-report) involved in-depth personal interviews. LEVEL 3 consisted of several direct examination assessments including a medical/psychiatric examination by a board certified psychiatrist, eight weeks of twice per week urine drug screens, an EEG exam and eight hours of neuropsychological testing. Results indicated that 39.0% of subjects passing self-report screening had significant exclusion criteria findings that were only detected through LEVEL 3 direct examination procedures. Of all subjects found to have exclusion criteria after being provisionally accepted following LEVEL 1 telephone pre-screening, 55.7% were detected only through more rigorous LEVEL 3 direct examination screening methods.

The use of the L-plastin promoter for adenoviral-mediated, tumor-specific gene expression in ovarian and bladder cancer cell lines

A 2.4-kb truncated L-plastin promoter was inserted either 5' to the LacZ gene (Ad-Lp-LacZ) or 5' to the cytosine deaminase (CD) gene (Ad-Lp-CD) in a replication-incompetent adenoviral vector backbone. Infectivity and cytotoxicity experiments with the LacZ and CD vectors suggested that the L-plastin promoter-driven transcriptional units were expressed at much higher levels in explants of ovarian cancer cells from patients and in established ovarian or bladder cancer cell lines than they were in normal peritoneal mesothelial cells from surgical specimens, in organ cultures of normal ovarian cells, or in the established CCD minimal deviation fibroblast cell line. Control experiments showed that this difference was not attributable to the lack of infectivity of the normal peritoneal cells, the normal ovarian cells, or the minimal deviation CCD fibroblast cell line, because these cells showed expression of the LacZ reporter gene when exposed to the replication-incompetent adenoviral vector carrying the cytomegalovirus (CMV)-driven LacZ gene (Ad-CMV-LacZ). The Ovcar-5 and Skov-3 ovarian cancer cell lines exposed to the Ad-Lp-CD adenoviral vector were much more sensitive to the prodrug 5-fluorocytosine (5FC), which is converted from the 5FC prodrug into the toxic chemical 5-fluorouracil, than was the CCD minimal deviation fibroblast cell line after exposure to the same vector. A mouse xenograft model was used to show that the Ad-Lp-CD vector/5FC system could prevent engraftment of ovarian cancer cells in nude mice. Finally, injection of the Ad-Lp-CD vector into s.c. tumor nodules generated a greater reduction of the size of the tumor nodules than did injection of the Ad-CMV-LacZ vectors into tumor nodules. The Ad-Lp-CD vectors were as suppressive to tumor growth as the Ad-CMV-CD vectors. These results suggest that an adenoviral vector carrying the CD gene controlled by the L-plastin promoter (Ad-Lp-CD) may be of potential value for the i.p. therapy of ovarian cancer.

Topographic quantitative EEG sequelae of chronic marihuana use: a replication using medically and psychiatrically screened normal subjects

In two previous studies it was reported that chronic marihuana (THC) use was associated with unique quantitative EEG features which were present in the non-intoxicated state. THC users, as contrasted with controls, had significant elevations of Absolute Power, Relative Power, and Coherence of alpha activity over the bilateral frontal cortex. Furthermore, a quantitative EEG discriminant function analyses permitted a 95% correct user versus non-user classification. However, because all of the THC users and 58% of the non-user controls were psychiatric inpatients, diagnostic and medication effects, if any, were uncontrolled. In the present study the same quantitative EEG methods were used to study daily THC users and non-user controls who underwent a rigorous screening process to insure that they were medically and psychiatrically healthy. The results of previous studies were replicated and an additional EEG correlate of chronic THC exposure (reduced alpha frequency) was identified.

Reduced P50 auditory gating response in psychiatrically normal chronic marihuana users: a pilot study

BACKGROUND

Neurophysiological studies of marihuana (THC) often contain uncontrolled confounds [psychiatric diagnoses, polydrug use, central nervous system (CNS)-relevant injury, etc.] that can alter electrophysiological measures. This P50 sensory gating report is part of a larger neurophysiological and neurocognitive investigation of chronic THC exposure using rigorously screened medically and psychiatrically normal individuals without concurrent use of non-THC substances.

METHODS

Following medical and psychiatric screening, including serial urine drug screens, technically adequate P50 paired auditory recovery tests were obtained on 19 chronic THC users and 14 control subjects. Fifty pairs of 80-dB auditory clicks (1 pair per 10 sec, 500-msec interclick separation) were delivered through earphones. The sensory gating measure was the ratio between the P50 amplitudes at the vertex elicited by the conditioning (first) and test (second) click.

RESULTS

THC subjects had significantly higher sensory gating ratios (i.e., reduced suppression) than did control subjects. Among THC users, sensory gating ratios did not correlate with duration or frequency of THC use, although subjects with ratios above 40 had nearly twice the number of "joint-years" of THC exposure than did those with lower ratios.

CONCLUSIONS

Reduced P50 suppression in the sensory gating paradigm may be a possible neurophysiological CNS sequela of long-term cumulative exposure to THC.

Use of L-plastin promoter to develop an adenoviral system that confers transgene expression in ovarian cancer cells but not in normal mesothelial cells

The objective of this study was to develop an adenoviral vector system that would generate a pattern of expression of exogenous therapeutic genes appropriate for the treatment of ovarian cancer. For this purpose, we have generated a replication-deficient recombinant adenoviral vector, AdLPLacZ, which contains the human L-plastin (LP) promoter (LP-P) driving the Escherichia coli LacZ gene. LP is constitutively expressed at high levels in malignant epithelial cells but is not expressed in normal tissues, except at low levels in mature hematopoietic cells. Because adenoviral vectors infect early hematopoietic multilineage precursor cells only poorly or not at all, this vector would be of use in the peritoneal cavity and in vitro for marrow purging. We first analyzed the expression of the LacZ reporter gene in ovarian and breast cancer cell lines, normal fibroblasts, and leukemia cell lines using the adenoviral vector in which the LacZ gene is governed by the LP-P promoter (AdLPLacZ) or in which the LacZ gene is governed by the cytomegalovirus (CMV) promoter (AdCMVLacZ). We found equivalent and high levels of expression of beta-galactosidase (beta-gal) by AdLPLacZ and AdCMVLacZ vectors in the breast or ovarian cancer cell lines as well as in a fibrosarcoma cell line, indicating that the adenoviral vectors infected these cells and expressed their transgenes equally with the LP and CMV promoters. Expression of the LacZ gene with the CMV vector but not with the LP-P vector was observed in experiments with normal fibroblasts, indicating that the vectors infected the cells, but that the LP-P was not active within them. In hematopoietic cells such as U937 cells, no measurable beta-gal activity was detected in cells infected either by AdLPLacZ or by AdCMVLacZ, indicating that the adenoviral vectors were not infecting the cells. Although beta-gal activity was observed in fresh ascitic ovarian cancer cells after infection with adenoviral vectors containing CMV or the LP promoters, beta-gal activity was detected in a portion of a biopsy of normal peritoneum when the tissues were exposed to the AdCMVLacZ vector, but not when tissues were exposed to the AdLPLacZ vector. These results suggest that the transcription of therapeutic genes in cells infected by the AdLP vectors would be restricted to LP expression-positive ovarian carcinoma cells but would not be seen in the normal mesothelial cells of the peritoneal cavity. This possibility implies that adenoviral vectors carrying therapeutic genes driven by the LP-P would be of use for the intracavitary treatment ovarian cancer.

Emergency department use of aspirin in patients with possible acute myocardial infarction

BACKGROUND

Efforts have been made to improve the suboptimal use of aspirin after hospitalization.

OBJECTIVE

To assess the frequency and timing of aspirin administration in emergency department patients with possible myocardial infarction.

DESIGN

Retrospective record review.

SETTING

Emergency departments of four hospitals affiliated with the same university.

PATIENTS

All patients who were admitted to the four hospitals in 1994 for evaluation and treatment of suspected acute myocardial infarction.

MEASUREMENTS

The frequency and timing of aspirin administration and the definitive diagnosis established before discharge from the hospital.

RESULTS

Aspirin was not given to 253 of 463 emergency department patients (55%) who had a definitive diagnosis of acute myocardial infarction. Seventy-eight percent of patients who did receive aspirin received it more than 30 minutes after arrival in the emergency department.

CONCLUSION

Aspirin therapy is underutilized as the first intervention in patients who are admitted with suspected myocardial infarction.

Mutagenic activity of high-energy 532 nm ultra-short laser pulses

The mutagenic activity of green (532 nm) and infrared (1064 nm) ultra-short laser light pulses was tested in cultured Syrian hamster fibroblasts by a hypoxanthine phosphoribosyl-transferase (HPRT) mutagenesis assay. In 18 irradiation trials, cells were exposed to eight consecutive 100-ps pulses of either 532 nm or 1064 nm light from a Nd:YAG laser at average irradiances of 3.0 GW/cm2. The 532 nm irradiations produced Hprt mutations at an average observed frequency of 5.3-5.6 x 10(-6), 10-fold higher than control trials (P < 0.01), while 1064 nm irradiations produced only background (spontaneous mutation) frequencies. A HAT (hypoxanthine, aminopterin, thymidine) sensitivity test allowed us to infer that Hprt- clones, selected as 6-thioguanine-resistant clones, possessed mutations at the Hprt locus after 532 nm Nd:YAG laser irradiation. The mutagenic effects of 532 nm high-energy laser pulses and not 1064 nm wavelengths are discussed in light of a two-photon absorption hypothesis. These preliminary findings suggest that 460-590 nm visible-light lasers may be mutagenic to mammalian cells either as a result of two-photon absorption or through some other photochemical process that damages DNA.

Isoform-specific complementation of the yeast sac6 null mutation by human fimbrin

The actin cytoskeleton is a fundamental component of eukaryotic cells, with both structural and motile roles. Actin and many of the actin-binding proteins found in different cell types are highly conserved, showing considerable similarity in both primary structure and biochemical properties. To make detailed comparisons between homologous proteins, it is necessary to know whether the various proteins are functionally, as well as structurally, conserved. Fimbrin is an example of a cytoskeletal component that, as shown by sequence determinations and biochemical characterizations, is conserved between organisms as diverse as Saccharomyces cerevisiae and humans. In this study, we examined whether the human homolog can substitute for the yeast protein in vivo. We report here that two isoforms of human fimbrin, also referred to as T- and L-plastin, can both substitute in vivo for yeast fimbrin, also known as Sac6p, whereas a third isoform, I-fimbrin (or I-plastin), cannot. We demonstrate that the human T- and L-fimbrins, in addition to complementing the temperature-sensitive growth defect of the sac6 null mutant, restore both normal cytoskeletal organization and cell shape to the mutant cells. In addition, we show that human T- and L-fimbrins can complement a sporulation defect caused by the sac6 null mutation. These findings indicate that there is a high degree of functional conservation in the cytoskeleton, even between organisms as diverse as S. cerevisiae and humans.

Regulation of synthesis of the transformation-induced protein, leukocyte plastin, by ovarian steroid hormones

Previous studies indicated that, among normal cells, only those of hemopoietic lineages expressed the abundant leukocyte phosphoprotein, L-plastin, and that activation of the L-plastin gene frequently occurred in malignant cells of solid tumors. We discovered that the gene encoding L-plastin contains potential estrogen and progesterone response elements upstream from its promoter, suggesting that L-plastin expression is subject to ovarian steroid regulation. To determine if L-plastin synthesis is regulated by ovarian steroids (estrogens and progestins), we examined cultured uterine endometrial stromal cells (SC) which are known to be responsive to ovarian steroids in a fashion that approximates the normal endometrium. Primary SC, which synthesized estrogen receptor and progesterone receptor mRNA transcripts, dramatically elevated L-plastin transcript synthesis in response to treatment with estradiol (E2) and medroxyprogesterone acetate (MPA). Stimulation of L-plastin synthesis by E2 and MPA was also evident by examination of protein synthesis using high-resolution two-dimensional gel electrophoresis and Western blotting. By contrast, SC that were propagated through multiple culture passages exhibited a coordinate decline in L-plastin, estrogen receptor, and progesterone receptor transcript levels and L-plastin protein synthesis. No other intracellular proteins could be found that were modulated significantly by E2 and MPA, but secretory protein synthesis was profoundly affected by E2 and MPA. Like L-plastin synthesis, hormone-mediated secretory protein synthesis was lost after propagation of the SC culture and reduction of estrogen receptor and progesterone receptor transcript synthesis. Our findings suggest that L-plastin synthesis is regulated coordinately with secretory protein synthesis in endometrial SC by estrogens and progestins.

Activation of the leukocyte plastin gene occurs in most human cancer cells

Examination of human neoplastic cell lines using reverse transcription-polymerase chain reaction (RT-PCR), Northern blotting, and protein profiling revealed that > 90% of transformed human cell lines surveyed exhibited widely varying degrees of activation of the leukocyte (L)-plastin gene. By contrast, diploid cell types exhibited no evidence of event transient activation of this gene. The low level activation of the L-plastin gene, detectable only by RT-PCR, was confirmed by using the recombinant human L-plastin promoter to select "L-plastin positive" clonal subpopulations from these RT-PCR-positive cell lines. A stable cell line selected by this method exhibited low level constitutive synthesis of L-plastin mRNA and polypeptide. This cell line also exhibited the coinduction of at least three highly abundant new cytoplasmic proteins (M(r) 42,000, 37,000, and 34,000) and reduction in growth rate and saturation density. Most clonal cell lines derived by this selection procedure that activated the L-plastin gene exhibited a crisis stage that led to death of the clonal strain, a phenomenon that could be reproduced by induction of synthesis of recombinant L-plastin from its complementary DNA.

Discovery and characterization of two novel human cancer-related proteins using two-dimensional gel electrophoresis

Comparative examination of protein synthesis in normal and neoplastic human fibroblasts led to the discovery of two novel microfilament proteins with roles in human neoplasia. One protein, a mutant beta-actin was found to convert nontumorigenic human fibroblasts to tumorigenicity. Recently, the oncogenic potential of this mutant beta-actin was verified independently and shown to alter the metastatic phenotype of human cells in conjunction with the myc and ras oncogenes. A second protein, leukocyte plastin, was discovered to be a marker of a majority of human cancer cells of nonhemopoietic origin. A survey of SV40-transformed human fibroblasts and human sarcoma and carcinoma cell types demonstrated that the L-plastin gene was activated at widely varying degrees in nearly all human cancer cells. Activation of the L-plastin gene was not detected in normal nonhemopoietic cells using sensitive reverse transcript-polymerase chain reaction, excepting those cells that expressed estrogen and progesterone receptors which mediate activation of L-plastin synthesis in reproductive tissues. Our most recent findings have revealed that activation of L-plastin synthesis in neoplastic cells that cannot phosphorylate L-plastin (e.g. those neoplastic cell types that express only trace amounts of L-plastin) results in the coinduction of two alternative inflammatory programs of gene expression which mediate cytolytic effects on surrounding cells. This inflammatory response appears to be mediated by "inappropriate" constitutive synthesis of L-plastin and failure of the induced cell to phosphorylate L-plastin. Our findings suggest explanations for the novel resistance of human cells to in vitro transformation and one role of oncogene activation in cancer. As a consequence of the interplay of two-dimensional (2-D) gel electrophoretic analyses with other sophisticated techniques of molecular biology, the formal characterization of two fundamentally important multigene families was completed with determination of many aspects of the structure and function of these proteins and their genes. The discovery and characterization of the mutant beta-actin and L-plastin and their relationship to the human neoplastic phenotype serve as useful models for the discovery of other important disease-related proteins/genes using 2-D gel electrophoresis.

Human plastin genes. Comparative gene structure, chromosome location, and differential expression in normal and neoplastic cells

Plastins are a family of actin-binding proteins that are conserved throughout eukaryote evolution and expressed in most tissues of higher eukaryotes. In humans, two ubiquitous plastin isoforms (L and T) have been identified. The L isoform is expressed only in hemopoietic cell lineages, while the T isoform has been found in all other normal cells of solid tissues that have replicative potential (fibroblasts, endothelial cells, epithelial cells, melanocytes, etc.). However, L-plastin has been found in many types of malignant human cells of non-hemopoietic origin suggesting that its expression is induced accompanying tumorigenesis in solid tissues. To learn more about the nature of plastin genes and their potential role in malignancy, the L- and T- plastin genes were cloned and sequenced to characterize their structure and mechanisms of regulation of expression. Each gene was found to be approximately 90 kilobases in size and was composed of 16 exons. All exon-intron junction sequences were identified and shown to conform to the canonical junction sequences. It was evident from their similar structure and coding homology that the two plastin genes have diverged from a common ancestor gene. L- and T-plastin genes were also mapped to chromosomes 13 and X, respectively, using polymerase chain reaction amplification with isoform-specific probes. An expanded survey of normal cell types and 50 tumor cell lines, demonstrated that 68% of carcinomas and 53% of other solid tumors of nonepithelial origin exhibited L-plastin expression, whereas the normal stem cell progenitors did not. Fibrosarcomas (n = 4), ovarian carcinomas (n = 9), breast carcinomas (n = 4), and choriocarcinomas (n = 2) combined exhibited the highest frequency and levels of L-plastin expression (95% frequency). In addition, 4 tumor cell lines that were L-plastin-negative exhibited evidence of defective T-plastin expression increasing the apparent co-incidence of plastin abnormalities associated with human tumorigenesis to 71%. Evidence is presented in support of a trans-activation mechanism for activation of L-plastin synthesis accompanying tumorigenesis. The induction of L-plastin expression accompanying SV40-mediated transformation of human embryonic lung MRC-5 fibroblasts was also confirmed. Finally, we present evidence that fimbrin is a third distinct plastin isoform which is specifically expressed at high levels in the small intestine.

Characterization of the human L-plastin gene promoter in normal and neoplastic cells

Plastins are a family of human actin-binding proteins (isoforms) which are abundantly expressed in all normal replicating mammalian cells. One isoform, L-plastin, is constitutively expressed at high levels in hemopoietic cell types while T-plastin is constitutively expressed in all non-hemopoietic cells of solid tissues that have replicative potential (fibroblasts, endothelial cells, epithelial cells, melanocytes, etc.). L-plastin is, however, constitutively synthesized in many types of malignant human cells of solid tissues suggesting that its expression is induced during tumorigenesis. The frequency of L-plastin induction in some cancers of the steroid-regulated female reproductive tract (breast, ovary, uterus, and placenta) appears to be especially high (79% in a limited survey). To learn the mechanism of L-plastin gene activation accompanying tumorigenesis, we have begun to characterize the promoter and regulatory elements of the L-plastin gene. Transcription initiation from this promoter was found to occur at multiple sites and as near as 10 base pairs from the 3'-side of the TATAAA box. The promoter and its flanking DNA were cloned and sequenced to identify potential regulatory elements that participate in the induction of the L-plastin gene in neoplastic cells. Examination of upstream sequences revealed the existence of two potential progesterone, one potential estrogen, and four potential Ets-1 responsive elements flanking the promoter. A 315-base pair fragment spanning the TATAAA box and a potential Sp1-binding site exhibited maximum promoter activity using CAT as a reporter while longer promoter fragments extending into upstream flanking sequences spanning the hormone receptor-response elements exhibited reduced promoter activity. An expression vector, pHLPPr-1-neo, was constructed using a 5.1-kilobase pair EcoRI-HindIII fragment of the L-plastin gene that contained the potential upstream regulatory elements, the TATAAA box, and part of the first exon. This promoter could direct the constitutive expression of the reporter beta-galactosidase at high frequency in transfected colonies of transformed cells that express L-plastin constitutively; by contrast, this promoter was virtually inactive in transfected colonies of normal fibroblasts and it exhibited a low frequency of constitutive activation in transfected colonies of in vitro SV40-transformed fibroblasts which did not exhibit L-plastin expression. The utility of this recombinant promoter in determining the mechanism(s) that leads to activation of the L-plastin gene in tumor cells is discussed. The potential significance of regulation of the L-plastin gene by reproductive hormones in cancers arising in hormone-responsive tissues is also discussed.

Fimbrin is a homologue of the cytoplasmic phosphoprotein plastin and has domains homologous with calmodulin and actin gelation proteins

Fimbrin is an actin-bundling protein found in intestinal microvilli, hair cell stereocilia, and fibroblast filopodia. The complete protein sequence (630 residues) of chicken intestine fimbrin has been determined from two full-length cDNA clones. The sequence encodes a small amino-terminal domain (115 residues) that is homologous with two calcium-binding sites of calmodulin and a large carboxy-terminal domain (500 residues) consisting of a fourfold-repeated 125-residue sequence. This repeat is homologous with the actin-binding domain of alpha-actinin and the amino-terminal domains of dystrophin, actin-gelation protein, and beta-spectrin. The presence of this duplicated domain in fimbrin links actin bundling proteins and gelation proteins into a common family of actin cross-linking proteins. Fimbrin is also homologous in sequence with human L-plastin and T-plastin. L-plastin is found in only normal or transformed leukocytes where it becomes phosphorylated in response to IL 1 or phorbol myristate acetate. T-plastin is found in cells of solid tissues where it does not become phosphorylated. Neoplastic cells derived from solid tissues express both isoforms. The differences in expression, sequence, and phosphorylation suggest possible functional differences between fimbrin isoforms.

Sequence analysis of proteins separated by polyacrylamide gel electrophoresis: towards an integrated protein database

Improved technologies or the synergistic use of complementary methods enhance the efficiency of research and permit the exploration of new approaches for the investigation of complex problems. High sensitivity protein sequence analysis and polyacrylamide gel electrophoresis are such complementary methods. Here we summarize the current status of high sensitivity sequence analysis of proteins separated in polyacrylamide gels and discuss strategies by which this technology can enhance biological research by generating new approaches for the solution of complex, multifacetted problems. Finally, we outline imminent technological advances in the area of high sensitivity protein sequence analysis and argue that further technological developments will ultimately lead to the generation of an integrated protein database (containing structural and functional as well as physiological information in an easily accessible form) of all the proteins separated by high resolution two-dimensional gel electrophoresis.

Correction of the N-terminal sequences of the human plastin isoforms by using anchored polymerase chain reaction: identification of a potential calcium-binding domain

Plastins are a family of at least three cytoplasmic protein isoforms that are expressed differentially between cells of the hematopoietic lineages and cells of solid tissues. Expression of the L-plastin isoform appears to be restricted to replicating blood cells, and the two T-plastin isoforms appear to be restricted to replicating cells of solid tissues. However, L-plastin is induced in many human solid tumor-derived cells. We used the anchored polymerase chain reaction technique to amplify and clone the missing 5' ends of plastin mRNAs. We found that both plastin isoforms contain a potential calcium binding site near the N terminus.

Homozygote for Huntington disease

Four offspring of three different Huntington disease (HD) affected x affected matings were assessed by genetic linkage analysis for possible homozygosity. One individual was found to have a 95% likelihood of being an HD homozygote. The homozygote individual had an age at onset and symptoms which were similar to those of affected HD heterozygote relatives, including some with younger onset. This confirms the observation of Wexler et al. that in HD the homozygote is not more severely afflicted than the heterozygote.

Regulation of the human beta-actin promoter by upstream and intron domains

We have identified three regulatory domains of the complex human beta-actin gene promoter. They span a region of about 3000 bases, from not more than -2011 bases upstream of the mRNA cap site to within the 5' intron (832 bases long). A distal upstream domain contains at least one enhancer-like element. A proximal upstream domain, with a CArG [for CC(A + T rich)6GG] motif found in all known mammalian actin genes, seems to confer serum, but not growth factor, inducibility. The third domain is within the evolutionarily conserved 3' region of the first intron and contains a 13 base-pair sequence, identical to the upstream sequence with the CArG motif. This domain also contains sequences that are both serum and fibroblast growth factor inducible.

Mapping of D4S98/S114/S113 confines the Huntington's defect to a reduced physical region at the telomere of chromosome 4

The dominant gene defect in Huntington's disease (HD) is linked to the DNA marker D4S10, near the telomere of the chromosome 4 short arm. Two other markers, D4S43 and D4S95, are closer, but still proximal to the HD gene in 4p16.3. We have characterized a new locus, D4S114, identified by cloning the end of a NotI fragment resolved by pulsed-field gel electrophoresis. D4S114 was localized distal to D4S43 and D4S95 by both physical and genetic mapping techniques. The "end"-clone overlaps a previously isolated NotI "linking" clone, and is within 150 kb of a second "linking" clone defining D4S113. Restriction fragment length polymorphisms for D4S113 and D4S114, one of which is identical to a SacI polymorphism detected by the anonymous probe pBS731B-C (D4S98), were typed for key crossovers in HD and reference pedigrees. The data support the locus order D4S10-(D4S43, D4S95)-D4S98/S114/S113-HD-telomere. The D4S98/S114/S113 cluster therefore represents the nearest cloned sequences to HD, and provides a valuable new point for launching directional cloning strategies to isolate and characterize this disease gene.

Molecular cloning and characterization of plastin, a human leukocyte protein expressed in transformed human fibroblasts

The phosphoprotein plastin was originally identified as an abundant transformation-induced polypeptide of chemically transformed neoplastic human fibroblasts. This abundant protein is normally expressed only in leukocytes, suggesting that it may play a role in hemopoietic cell differentiation. Protein microsequencing of plastin purified from leukemic T lymphocytes by high-resolution two-dimensional gel electrophoresis produced eight internal oligopeptide sequences. An oligodeoxynucleotide probe corresponding to one of the oligopeptides was used to clone cDNAs from transformed human fibroblasts that encoded the seven other oligopeptides predicted for human plastin. Sequencing and characterization of two cloned cDNAs revealed the existence of two distinct, but closely related, isoforms of plastin--l-plastin, which is expressed in leukocytes and transformed fibroblasts, and t-plastin, which is expressed in normal cells of solid tissues and transformed fibroblasts. The leukocyte isoform l-plastin is expressed in a diverse variety of human tumor cell lines, suggesting that it may be involved in the neoplastic process of some solid human tumors.

Macromolecular changes accompanying immortalization and tumorigenic conversion in a human fibroblast model system

Mutagenesis of a diploid human fibroblast strain, KD, with the chemical carcinogen 4 nitroquinolin-1-oxide led to the isolation of stably immortalized neoplastic substrains. Four of these transformed strains, HuT-11, -12, -13, and -14, have been characterized in great detail with regard to morphology and changes in gene expression from the parental KD strain. The HuT-11, -12 and -13 substrains are immortalized and non-tumorigenic, in contrast to HuT-14 which is both immortalized and tumorigenic. The HuT-14 substrain expresses a defective beta-actin as a consequence of a point mutation in 1 of the 2 functional beta-actin alleles. All 4 HuT strains have induced expression of the phosphoprotein plastin and 2 EGF-related polypeptides, and down-regulated expression of the transformation-sensitive tropomyosin isoforms. KD and HuT cells expressing high levels of exogenous mutant beta-actin after gene transfection show morphological alterations. HuT-12 transfectants with excessive mutant beta-actin expression exhibit an elevated tumorigenic potential and tropomyosin-isoform switching characteristic of the tumorigenic HuT-14 strain.

Modulation of microfilament protein composition by transfected cytoskeletal actin genes

HuT-14T is a highly tumorigenic fibroblast cell line which exhibits a reduced steady-state level of beta-actin due to coding mutations in one of two beta-actin alleles. The normal rate of total actin synthesis could be restored in some clones of cells following transfection of the functional beta-actin gene but not following transfection of the functional gamma-actin gene. In gamma-actin gene-transfected substrains that have increased rates of gamma-actin synthesis, beta-actin synthesis is further reduced in a manner consistent with an autoregulatory mechanism, resulting in abnormal ratios of actin isoforms. Thus, both beta- and gamma-actin proteins can apparently regulate the synthesis of their coexpressed isoforms. In addition, decreased synthesis of normal beta-actin seems to correlate with a concomitant down-regulation of tropomyosin isoforms.

Cloning and characterization of a cDNA encoding transformation-sensitive tropomyosin isoform 3 from tumorigenic human fibroblasts

We isolated a cDNA clone from the tumorigenic human fibroblast cell line HuT-14 that contains the entire protein coding region of tropomyosin isoform 3 (Tm3) and 781 base pairs of 5'- and 3'-untranslated sequences. Tm3, despite its apparent smaller molecular weight than Tm1 in two-dimensional gels, has the same peptide length as Tm1 (284 amino acids) and shares 83% homology with Tm1. Tm3 cDNA hybridized to an abundant mRNA of 1.3 kilobases in fetal muscle and cardiac muscle, suggesting that Tm3 is related to an alpha fast-tropomyosin. The first 188 amino acids of Tm3 are identical to those of rat or rabbit skeletal muscle alpha-tropomyosin, and the last 71 amino acids differ from those of rat smooth muscle alpha-tropomyosin by only 1 residue. Tm3 therefore appears to be encoded by the same gene that encodes the fast skeletal muscle alpha-tropomyosin and the smooth muscle alpha-tropomyosin via an alternative RNA-splicing mechanism. In contrast to Tm4 and Tm5, Tm3 has a small gene family, with, at best, only one pseudogene.

A 60-kDa polypeptide in mammalian cells with epitopes related to actin

We have identified a novel actin-related 60-kDa polypeptide in mammalian cells. The relatedness of this polypeptide to actin is indicated by its affinity for DNase I, two monoclonal anti-actin antibodies, and two independent peptide-specific anti-actin antibodies which bind to actin at around amino acid 244. It is not incorporated into cytoskeletal stress fibers, although it is a stable protein. Its expression (60-kDa polypeptide, pI of 5.4 to 5.5) is inhibited by the K+ ionophore, nonactin, which is known to collapse the energy-dependent translocation of cytoplasmically synthesized proteins into mitochondria.

Internal amino acid sequence analysis of proteins separated by one- or two-dimensional gel electrophoresis after in situ protease digestion on nitrocellulose

We have developed a general two-step method for obtaining peptide fragments for sequence analysis from picomole quantities of proteins separated by gel electrophoresis. After separation by one- or two-dimensional polyacrylamide gel electrophoresis, proteins are electrophoretically transferred (electroblotted) onto nitrocellulose, the protein-containing regions are detected by reversible staining and are cut out, and each protein is digested in situ by proteolytic enzymes such as trypsin or staphylococcal V-8 protease. The resulting peptide fragments are separated by narrow-bore reverse-phase HPLC, collected, and sequenced in a gas-phase sequenator. Excellent peptide recoveries and the absence of extraneous contaminants in the separation of the peptide fragment mixture allow the generation of extensive internal sequence information from picomole amounts of protein. The method thus overcomes the problem of obtaining amino acid sequence data from N-terminally blocked proteins and provides multiple, independent stretches of sequence that can be used to generate oligonucleotide probes for molecular cloning and/or used to search sequence data bases for related proteins. This method has been successfully applied to the routine amino acid sequence analysis of a wide range of proteins isolated from one- and two-dimensional polyacrylamide gels.

A human beta-actin expression vector system directs high-level accumulation of antisense transcripts

We have constructed a mammalian expression vector consisting of 3 kilobases of the human beta-actin gene 5' flanking sequence plus 5' untranslated region and intervening sequence 1 linked at the 3' splice site to a short DNA polylinker sequence containing unique Sal I, HindIII, and BamHI restriction endonuclease sites followed by a simian virus 40 (SV40) polyadenylylation signal. Two derivatives, containing the selection markers obtained from pSV2gpt or pSV2neo, were also generated. We find that the promoter activity of this vector is a great or greater than that of the SV40 early promoter in a variety of human and rodent cells. The vector was used to generate gamma-actin and beta-tubulin antisense transcripts in human fibroblast cell lines. The antisense transcripts accumulate to levels comparable with that of the highly abundant gamma-actin and beta-tubulin mRNAs.

Expression of transfected mutant beta-actin genes: alterations of cell morphology and evidence for autoregulation in actin pools

Two different mutant human beta-actin genes have been introduced into normal diploid human (KD) fibroblasts and their immortalized derivative cell line, HuT-12, to assess the impact of an abnormal cytoskeletal protein on cellular phenotypes such as morphology, growth characteristics, and properties relating to the neoplastic phenotype. A mutant beta-actin containing a single mutation (Gly-244----Asp-244) was stable and was incorporated into cytoskeletal stress fibers. Transfected KD cells which expressed the stable mutant beta-actin in excess of normal beta-actin were morphologically altered. In contrast, a second mutant beta-actin gene containing two additional mutations (Gly-36----Glu-36 and Glu-83----Asp-83, as well as Gly-244----Asp-244) did not alter cell morphology when expressed at high levels in transfected cells, but the protein was labile and did not accumulate in stress fibers. In both KD and HuT-12 cells, endogenous beta- and gamma-actin decreased in response to high-level expression of the stable mutant beta-actin, in a manner consistent with autoregulatory feedback of actin concentrations. Since the percent decreases in the endogenous beta- and gamma-actins were equal, the ratio of net beta-actin (mutant plus normal) to gamma-actin was significantly increased in the transfected cells. Antisera capable of distinguishing the mutant from the normal epitope revealed that the mutant beta-actin accumulated in stress fibers but did not participate in the formation of the actin filament-rich perinuclear network. These observations suggest that different intracellular locations differentially incorporate actin into cytoskeletal microfilaments. The dramatic impact on cell morphology and on beta-actin/gamma-actin ratios in the transfected diploid KD cells may be related to the acquisition of some of the characteristics of cells that underwent the neoplastic transformation event that originally led to the appearance of the beta-actin mutations.

Expression of transfected mutant beta-actin genes: transitions toward the stable tumorigenic state

Mutant human beta-actin genes were introduced into normal human (KD) fibroblasts and the derivative cell line HuT-12, which is immortalized but nontumorigenic, to test their ability to promote conversion to the tumorigenic state. Transfected substrains of HuT-12 fibroblasts that expressed abundant levels of mutant beta-actin (Gly-244----Asp-244) produced subcutaneous tumors in athymic mice after long latent periods (1.5 to 3 months). However, transfected substrains of KD fibroblasts retained their normal finite life span in culture and consequently were incapable of producing tumors. Substrains of HuT-12 cells transfected with the wild-type beta-actin gene and some transfected strains that expressed low or undetectable levels of mutant beta-actin did not produce tumors. Cell lines derived from transfectant cell tumors always exhibited elevated synthesis of the mutant beta-actin, ranging from 145 to 476% of the level expressed by the transfected cells that were inoculated to form the tumor. In general, primary transfectant cells that expressed the highest levels of mutant beta-actin were more tumorigenic than strains that expressed lower levels. The tumor-derived strains were stable in tumorigenicity and produced tumors with shortened latent periods of only 2 to 4 weeks. These findings imply that the primary transfectant strains develop subpopulations of cells that are selected to form tumors because of their elevated rate of exogenous mutant beta-actin synthesis. Actin synthesis and accumulation of gamma-actin mRNA from the endogenous beta- and gamma-actin genes were diminished in tumor-derived strains, apparently to compensate for elevated mutant beta-actin synthesis and maintain the normal cellular concentration of actin. Synthesis of the transformation-sensitive tropomyosin isoforms was decreased along with mutant beta-actin expression. Such modulations in tropomyosin synthesis are characteristically seen in transformation of avian, rodent, and human fibroblasts. Our results suggest that this mutant beta-actin contributes to the neoplastic phenotype of immortalized human fibroblasts by imposing a cytoarchitectural defect and inducing abnormal expression of cytoskeletal tropomyosins.

Tropomyosin isoform switching in tumorigenic human fibroblasts

We identified six tropomyosin (Tm) isoforms in diploid human fibroblasts. We used computerized microdensitometry of 2-dimensional protein profiles to measure the relative rates of synthesis and abundance of the individual Tm isoforms and actin, the two major structural constituents of microfilaments. In carcinogen-transformed human fibroblasts (HuT-14), the rates of synthesis of three Tm isoforms (Tm1, Tm2, and Tm6) were greatly decreased relative to normal diploid parental fibroblasts and to actin. In contrast, related nontumorigenic HuT fibroblasts which are "immortalized" and anchorage independent exhibited both slight down-regulation of Tm1 and Tm6 and 3.5-fold up-regulation of Tm3. Thus, Tm isoform switching from the predominance of the larger more avid Tm isoforms (Tm1, Tm2, Tm3, and Tm6) to the smaller, less avid Tm isoforms (Tm4 and Tm5) in microfilaments was a transformation-induced change correlated with tumorigenicity in human fibroblasts.

Abundant synthesis of the transformation-induced protein of neoplastic human fibroblasts, plastin, in normal lymphocytes

The transformation-induced protein plastin (p219; Mr 68,000, pl 5.3) is a reliable cytosolic marker for neoplastic human fibroblasts. Fibroblasts transformed in vitro by chemical carcinogens or SV40 virus and tumor-derived cancer cells of fibroblastoid or epithelioid origin usually express plastin and p220, a minor phosphorylated form of plastin. We report here that plastin is expressed as one of the most abundant proteins of normal, untransformed lymphocytes. The phosphorylated form of plastin was detectable in adherent monocytes but not in purified T- or NK lymphocytes. We also demonstrate that an allelic variant or mutated form of plastin exhibiting altered charge is found at a reduced frequency in the human population. We discuss the possible significance of these observations in terms of evaluating the role of plastin induction in expression of the cancerous phenotype of fibroblasts.

Pulfrich stereo-illusion phenomenon in serous sensory retinal detachment of the macula

Four patients (three men, 68, 35, and 33 years old, and one woman, 46 years old) had central serous elevation of the macula with abnormal latency of the visual-evoked potential and spontaneous Pulfrich phenomenon. In three instances both the electrophysiologic test and the clinical Pulfrich test reverted to normal on resolution of the retinopathy. This correlated with normalization of visual-evoked potential latency in the affected eye.

Identification and order of sequential mutations in beta-actin genes isolated from increasingly tumorigenic human fibroblast strains

We have sequenced the mutant beta-actin gene of a tumorigenic human fibroblast cell line (HuT-14T) and found that it carries three mutations that alter the amino acids at positions 36, 83, and 244 as well as a 22-base-pair "insertion" sequence, in the 5' intron, not present in a wild-type gene. The less tumorigenic cell line HuT-14, a progenitor of HuT-14T, has the same codon-244 mutation and the insertion sequence but not the other two mutations. A nontumorigenic cell line that is related to HuT-14 but that has no beta-actin mutations does carry the intron-length polymorphism. We conclude that the mutation at codon 244 occurred first in a beta-actin allele already bearing the 22-base-pair intron insert and that mutations at codons 36 and 83 arose subsequently during the selection for the HuT-14T phenotype. Rat-2 cells synthesize the appropriate charge-variant species of mutant actin protein when transfected with either the singly or the triply mutated beta-actin gene.

Evolution of the functional human beta-actin gene and its multi-pseudogene family: conservation of noncoding regions and chromosomal dispersion of pseudogenes

We have assigned six members of the human beta-actin multigene family to specific human chromosomes. The functional gene, ACTB, is located on human chromosome 7, and the other assigned beta-actin-related sequences are dispersed over at least four different chromosomes including one locus assigned to the X chromosome. Using intervening sequence probes, we showed that the functional gene is single copy and that all of the other beta-actin related sequences are recently generated in evolution and are probably processed pseudogenes. The entire nucleotide sequence of the functional gene has been determined and is identical to cDNA clones in the coding and 5' untranslated regions. We have previously reported that the 3' untranslated region is well conserved between humans and rats (Ponte et al., Nucleic Acids Res. 12:1687-1696, 1984). Now we report that four additional noncoding regions are evolutionarily conserved, including segments of the 5' flanking region, 5' untranslated region, and, surprisingly, intervening sequences I and III. These conserved sequences, especially those found in the introns, suggest a role for internal sequences in the regulation of beta-actin gene expression.

Smooth muscle alpha-action is a transformation-sensitive marker for mouse NIH 3T3 and Rat-2 cells

Heteroploid mouse NIH 3T3 fibroblasts and several rat fibroblast strains (Rat-1, Rat-2 and REF-52) are cell lines of special interest in the field of carcinogenesis because of their extensive use as normal cells in transformation assays for putative cancer-causing genes. Exposure of these cells to carcinogenic chemicals or oncogenic DNA produces anchorage-independent cells with retracted cytoplasms that lack actin cables. All human fibroblast strains, normal and transformed, synthesize two electrophoretic forms of actin (beta- and gamma-actin). In contrast, we discovered that early-passage mouse and rat strains synthesize abundant amounts of each of the three electrophoretic forms of actin (alpha-, beta- and gamma-actin) but mouse and rat cancer cells express only beta- and gamma-actins. We now show that in NIH 3T3 and Rat-2 fibroblasts a third actin, the smooth muscle alpha isoform, is abundantly co-expressed with beta- and gamma-actin. In every instance tested following transformation to tumorigenicity, the accumulation of alpha-actin messenger RNA and alpha-actin synthesis was greatly inhibited. Shutdown of alpha-actin expression thus appears to be a reproducible transformation-sensitive marker in rodent fibroblasts.

Expression of neoplasia-related proteins of chemically transformed HuT fibroblasts in human osteosarcoma HOS fibroblasts and modulation of actin expression upon elevation of tumorigenic potential

Two sets of abundant cytoplasmic transformation-specific polypeptides, p788/p789 and p219/p220, have been identified by comparing in vitro-transformed human fibroblasts with diploid human fibroblasts. These polypeptides are also expressed by the human fibrosarcoma and osteosarcoma cell lines HT1080 the human fibrosarcoma and osteosarcoma cell lines HT1080 and HOS, respectively. HOS cells, however, synthesize only one of the two electrophoretic forms of each marker set, p789 and p219, at greatly reduced rates compared to the rates of synthesis found for HT1080 cells and the in vitro-transformed cell lines. Induction of expression of these neoplastic marker polypeptides is independent of the activation of a transforming gene that will induce focus formation in confluent mouse 3T3 cell monolayers. Activation of the met oncogene in MNNG-HOS cells and simultaneous elevation of tumorigenic potential did not lead to a significant change in the rate of the 600 most abundant polypeptide species with the exception of one of the two cytoplasmic actin polypeptides. While the normal ratio of beta-to gamma-actin which is approximately 2:1 was expressed in "untransformed" HOS cells, MNNG-HOS cells synthesized 50% less beta-actin resulting in a 1:1 ratio of beta-actin to gamma-actin. Our finding here, together with our previous characterization of the human beta-actin gene, leads us to predict that one of two functional beta-actin genes expressed in HOS cells has been inactivated in MNNG-HOS cells by either a regulatory or structural gene mutation.

Identification of polypeptides on two-dimensional electrophoresis gels by amino acid composition

We present a method that can, in principle, provide tentative identification of a substantial proportion of the polypeptides resolvable on a given two-dimensional electrophoresis gel. Computerized microdensitometry of autoradiograms from 20 gels labeled in turn with each of the 20 common amino acids provides the data for simultaneously measuring the amino acid composition of all polypeptides of interest on the gel. These compositions are then compared with computer data bases of known protein compositions. Similarity between a known and an unknown polypeptide with comparable molecular mass indicates a potential identification, which can then be confirmed with conventional techniques. We illustrate this technique by applying it to the identification of proteins in a transformed human cell line (HuT-14).

Identification of polypeptides on two-dimensional electrophoresis gels by amino acid composition

We present a method that can, in principle, provide tentative identification of a substantial proportion of the polypeptides resolvable on a given two-dimensional electrophoresis gel. Computerized microdensitometry of autoradiograms from 20 gels labeled in turn with each of the 20 common amino acids provides the data for simultaneously measuring the amino acid composition of all polypeptides of interest on the gel. These compositions are then compared with computer data bases of known protein compositions. Similarity between a known and an unknown polypeptide with comparable molecular mass indicates a potential identification, which can then be confirmed with conventional techniques. We illustrate this technique by applying it to the identification of proteins in a transformed human cell line (HuT-14).

Molecular cloning and characterization of mutant and wild-type human beta-actin genes

There are more than 20 beta-actin-specific sequences in the human genome, many of which are pseudogenes. To facilitate the isolation of potentially functional beta-actin genes, we used the new method of B. Seed (Nucleic Acids Res. 11:2427-2446, 1983) for selecting genomic clones by homologous recombination. A derivative of the pi VX miniplasmid, pi AN7 beta 1, was constructed by insertion of the 600-base-pair 3' untranslated region of the beta-actin mRNA expressed in human fibroblasts. Five clones containing beta-actin sequences were selected from an amplified human fetal gene library by homologous recombination between library phage and the miniplasmid. One of these clones contained a complete beta-actin gene with a coding sequence identical to that determined for the mRNA of human fibroblasts. A DNA fragment consisting of mostly intervening sequences from this gene was then used to identify 13 independent recombinant copies of the analogous gene from two specially constructed gene libraries, each containing one of the two types of mutant beta-actin genes found in a line of neoplastic human fibroblasts. The amino acid and nucleotide sequences encoded by the unmutated gene predict that a guanine-to-adenine transition is responsible for the glycine-to-aspartic acid mutation at codon 244 and would also result in the loss of a HaeIII site. Detection of this HaeIII polymorphism among the fibroblast-derived clones verified the identity of the beta-actin gene expressed in human fibroblasts.

Neoplastic human fibroblast proteins are related to epidermal growth factor precursor

We report the amino acid composition of two polypeptides, p788 and p789. These polypeptides are reliable markers for neoplastic transformation in human fibroblasts. Their compositions are unusually rich in cysteine and serine. Because the recently reported amino acid sequence of mouse epidermal growth factor precursor (prepro-EGF) is also rich in those two amino acids and because the role of p788 and p789 as markers for neoplastic transformation is consistent with the fact that epidermal growth factor has been shown to play some role in transformation, we investigated the hypothesis that p788 and p789 are related to prepro-EGF. We compared the amino acid composition of p788 with that of all possible interior domains of prepro-EGF of appropriate length. We found that the composition of p788 is remarkably similar to that of residues 630-880 of prepro-EGF. The similarity is sufficiently strong to support the conclusion that it reflects amino acid sequence homology.

Limitations of the brief form of the Halstead Category Test

This study attempted to cross-validate a short form of the Category Test (subtests 1-4) first used by Calsyn, O'Leary, and Chaney (1980). One hundred and sixty-eight subjects were assigned to one of six neurological categories, and Category Test scores predicted (via regression analysis) from performance on the short form were compared with actual scores obtained from the original long form. While there was a high correlation (r = .91) between the two sets of scores, a large number of normal subjects were misclassified as brain-damaged. Additionally, subjects with focal right lesions could not be differentiated from normals either on the basis of error scores predicted from short form performance or the absolute number of errors made on subtests 1-4. These results suggested that shortening the Category Test may limit its applicability with certain populations.

A mutation in actin associated with neoplastic transformation

A new protein was recognized in a chemically transformed human fibroblast cell line when its proteins labeled with [35S]methionine were compared with those from normal human fibroblasts by two-dimensional gel electrophoresis. The new protein was found in the Triton-insoluble cytoskeletal fraction as well as in the Triton-soluble fraction, and it migrated very closely to beta- and gamma-actins on the gels. This new protein was identified as a variant form of actin by its reaction with antiactin antibody and its tryptic peptide pattern, which was identical to actin. mRNA coding for the variant actin was detected only in this particular transformed line. The size and cross- hybridizability with Dictyostelium actin cDNA of mRNA coding for the variant actin and complete amino acid sequence of the variant actin indicate that the new variant actin is the product of a mutated beta-actin gene. Only a single amino acid (glycine) at position 244 was replaced by aspartic acid. This substitution corresponds to a GC----AT transition, a point mutation. On the other hand, a highly malignant cell variant was isolated from the transformed line. The mutated beta-actin was further altered in this highly malignant subclone: it showed a more negative charge, rapid synthetic rate, and a short half-life in the cells. Incorporation into the cytoskeleton was significantly reduced in the mutated beta-actin. A hypothesis on the relationship between a mutation in the actin gene and oncogenic transformation was proposed.

Tumorigenic potential of human fibroblasts as a function of ability to express a novel form of influenza A nucleocapsid protein

Influenza A virus released by infected diploid human fibroblasts contains nearly equal amounts of two electrophoretic forms of the viral nucleocapsid protein NP (NP1 and NP2). Pulse-chase labeling and tryptic fingerprinting of NP1 and NP2 have suggested that NP1 is converted to NP2 late in the lytic cycle as a consequence of a post-translational proteolytic event. Within normal fibroblasts only one cellular form of NP (NP1) is detectable indicating that synthesis of NP2 is associated only with the release of virus from these normal cells. Four neoplastic substrains derived from the normal fibroblast strain exhibit varying degrees of neoplastic character in vitro and tumorigenic potential in athymic mice. This family of human fibroblast strains can be divided into three orders of tumorigenic potential: (i) normal and non-tumorigenic; (ii) neoplastic but rarely tumorigenic; and (iii) neoplastic and always tumorigenic. In contrast to the parental non-tumorigenic cell type which exhibits no cellular NP2, the two classes of neoplastic fibroblasts exhibit NP2 at abundance levels which appear to reflect the two elevated degrees of tumorigenic potential. Thus, assessment of influenza A gene expression may have detected a novel cellular protease which is incrementally elevated along with tumorigenic potential of this human fibroblast family.

Skin tags: a cutaneous marker for colonic polyps

The relation between adenomatous colonic polyps and the development of adenocarcinoma of the colon is well established. An association between skin tags and colonic polyps in patients with acromegaly has also been reported. To ascertain if skin tags are a cutaneous marker for colonic polyps independent of the presence of acromegaly, 100 men referred for colonoscopy were studied. Forty-six patients had colonic polyps and 37 also had skin tags; the correlation was highly significant (p less than 0.005). The sensitivity and specificity of the presence of skin tags serving as a cutaneous marker for adenomatous colonic polyps were both greater than 75%. Thus, at least in this population, skin tags may serve as a means for identifying patients at increased risk for having colonic polyps.

A randomized prospective study of vindesine versus doxorubicin and cyclophosphamide in the treatment of epidermoid lung cancer

A randomized prospective study was conducted comparing vindesine (VDS) with doxorubicin and cyclophosphamide (D/C) in the treatment of advanced squamous cell carcinoma of the lung. No patient had a complete response. Seven of 28 (25%) patients had partial response (PR) to VDS while one of 19 (5%) had a PR to D/C (P less than 0.08). Adding PR plus minor response (MR), ten of 28 (36%) patients responded to VDS while two of 19 (11%) responded to D/C (P less than 0.05). Median survival was improved among patients showing PR and MR over those not responding (P less than 0.05). This study concludes, VDS is an active agent in the treatment of squamous cell carcinoma of the lung and should be considered for combination chemotherapy and adjuvant trials. VDS toxicity appears acceptable with six weekly doses of 3 mg/m2. The benefit of a maintenance schedule could not be demonstrated.