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PubMed1994

Heterochronic expression of an adult muscle actin gene during ascidian larval development.

Adultation is a heterochronic mode of development in which adult tissues and organs differentiate precociously during the larval phase. We have investigated the expression of an adult muscle actin gene during adultation in the ascidian Molgula citrina. Ascidians contain multiple muscle actin genes which are expressed in the larva, the adult, or during both phases of the life cycle. In ascidian species with conventional larval development, the larval mesenchyme cells, which are believed to be progenitors of the adult mesoderm, remain undifferentiated and do not express the muscle actin genes. In M. citrina, the mesenchyme cells differentiate precociously during larval development, suggesting a role in adultation. An adult muscle actin gene from M. citrina was obtained by screening a mantle cDNA library with a probe containing the coding region of SpMA1, a Styela plicata adult muscle actin gene. The screen yielded a cDNA clone designated McMA1, which contained virtually the complete coding and 3' noncoding regions of a muscle actin gene. The deduced McMA1 and SpMA1 proteins exhibit 97% identity in amino acid sequence and may be encoded by homologous genes. The McMA1 gene is expressed in juveniles and adults, but not in larval tail muscle cells, suggesting that it is an adult muscle actin gene. In situ hybridization with a 3' non-coding region probe was used to determine whether the McMA1 gene is expressed during adultation in M. citrina. McMA1 mRNA was first detected exclusively in the mesenchyme cells during the late tailbud stage and continued to accumulate in these cells during their migration into the future body cavity and heart primordium in the hatched larva. The McMA1 transcripts persisted in mesenchyme cells after larval metamorphosis. It is concluded that an adult muscle actin gene shows a heterochronic shift of expression into the larval phase during adultation in M. citrina.

Actins↗
PubMed2002

Virtual endoscopy: current perspectives.

Virtual endoscopy is a new method for evaluating the gastrointestinal tract using either thin-section computed tomography (CT) or magnetic resonance imaging (MRI). The acquired data are then subjected to computer manipulation to render images simulating the conventional endoscopic view. CT and MR imaging data can provide information that is not accessible endoscopically. These important features include information on tissue extending through and beyond organ walls and the anatomic context of the entire gastrointestinal tract, which permits correct anatomic localization of the lesion. Many clinical studies have shown that it is a safe, noninvasive, well-tolerated alternative to conventional endoscopy. Virtual endoscopy may have potential as a method of screening for colorectal cancer. This review describes the technique, reviews reported results, and discusses the present and future applications of this technique, focusing on CT colography (CTC).

Colonic Neoplasms↗
PubMed2006

MR colonography: current status.

Magnetic resonance colonography (MRC) has gained access into clinical routine as a means for the assessment of the large bowel. There are widely accepted indications for MRC, especially in patients with incomplete conventional colonoscopy. Furthermore, virtual MRC is more and more propagated as a screening tool, with advantages especially inherent to the non-invasive character of this procedure and the lack of ionizing radiation exposition. Beyond a sufficiently high diagnostic accuracy, outstanding patient acceptance is a major advantage of MRC as a diagnostic modality. This review article describes indications, techniques and clinical outcome of current MRC approaches. Furthermore, the impact of fecal tagging concepts is discussed.

Colon↗
PubMed1992

Silent allelic variants of a T-cell receptor V beta 12 gene are present in diverse human populations.

Amino acid substitutions in variable regions of the T-cell receptor (TCR) can alter T-cell reactivity; however, relatively little is known about the extent of allelic variation in human TCR coding sequences. In the present studies, coding region variation in the human TCR V beta 12.2 gene was examined in detail. Virtually the entire V beta 12.2 coding region was screened for nucleotide substitutions by single-stranded conformational polymorphism analysis. Four alleles were identified in a sample population of 90 unrelated people from diverse genetic backgrounds. Three of the alleles were common, with estimated frequencies of 0.32, 0.47, and 0.20. Sequence analyses revealed that variation between the alleles was confined to three single-base differences in codons 24, 31, and 45; none of these changes altered the amino acid sequence. No evidence for other coding region differences in this gene were found. This analysis suggests that coding region variation in V beta 12.2 is limited, and amino acid sequence is highly conserved.

Alleles↗
PubMed2001

Action planning in a virtual context after prefrontal cortex damage.

Patients with frontal lobe lesions are known to encounter severe problems in the organisation of their behaviour in everyday life. Script generation tasks assess the subject's conceptual ability to formulate and evaluate a coherent and structured plan of action. In the present study, we investigated to what extent neuropsychological deficits observed at the conceptual level of action knowledge lead to impairments in action execution. We examined seven patients with prefrontal cortex damage and sixteen normal subjects. Subjects were first asked to verbally formulate a plan of action and then to use this knowledge for 'executing' the actions in a virtual 3-dimensional interactive apartment presented on a computer screen. The results indicated that the presence of the realistic context improved patients' performance. However, specific impairments were observed in patients in the execution condition, namely actions slips, omissions, failure in initiating actions and purposeless displacements. Moreover, an analysis of planning time showed that, differently of the patients group, normal subjects spent more time during plan execution as compared to plan generation. These results suggest that after a frontal lobe lesion a defective formulation of a routine plan might affect the execution of the corresponding course of actions.

Adult↗
PubMed1987

The radio-opacity of surgical and radiological devices used in vivo: a test method for markers in surgical gauze.

Most radio-opaque markers used in surgical gauze contain barium sulphate, and a minimum percentage content of this is required to ensure an acceptable level of radio-opacity. When this minimum percentage is specified by Standards authorities, a suitable test method must be available to determine compliance. A new radiographic test method is presented which can be used to determine the barium sulphate content or equivalence to within 2% of compliance requirements. The method consists of immersing the marker in a solution of barium sulphate which is then radiographed. Compliance can be evaluated by inspection of the radiograph. The method was found to be virtually independent of x-ray energy, film-screen combination and thickness or shape of the test object. The method is also an appropriate test for any other material or object, such as vascular catheters used in radiology or small toys which pose an ingestion hazard.

Barium Sulfate↗
PubMed1975

Screening for endometrial cancer.

Since Gusberg's description in 1947 of adenomatous hyperplasia (15), the role of precursors in the development of endometrial carcinoma has been well studied. There is now no doubt that in many patients histologic precursors can be demonstrated in the endometrial cavity prior to the development of invasive cancer. At this point in the continuum, interruption by hysterectomy or other therapy will insure the patient's health. We have discussed a wide variety of techniques designed to provide cytologic or histologic samples of the endometrium that are highly effective in the detection of early neoplasia. As a goal, universal endometrial sampling on a periodic basis is probably impractical and may be unecessary or undesirable. However, surely the patient at high risk for endometrial cancer requires close periodic screening. The high-risk category may be expanded to include others beyond the group of hypertensive, diabetic, obese, anovulatory, nulliparous women. It should include patients with irregular vaginal bleeding, those with a strong family history of genital and breast cancer, those patients receiving hormone therapy, and patients in the menopausal years who experience changes in the menstrual pattern. With intelligent and aggressive application of outpatient screening, uterine cancer can be diagnosed when patients are virtually completely curable, thus resulting in further reduction in mortality from this disease.

Adenocarcinoma↗
PubMed1987

Use of directly acquired digital fundus and fluorescein angiographic images in the diagnosis of retinal disease.

Direct on-line acquisition of digital fundus and fluorescein images is a useful alternative to conventional fundus photography. Immediately after acquisition, digital images may be electronically reassembled, manipulated, and displayed, avoiding the delays inherent in film development. Digital fundus images, conventional photographs, and fluorescein angiograms were obtained at the same sitting in 50 consecutive patients with retinal disease. Digital studies were displayed on a video monitor and diagnoses were made directly from the screen. The interpretations based on digital images alone were virtually identical to those made from photographs, although the resolution of digital images was not equal to that of the photographic images. Despite this disadvantage, the system proved extremely versatile, and for this reason, digital image acquisition was used to routinely document the retinal findings in the majority of the clinical patients.

Fluorescein Angiography↗
PubMed2002

Cell-type-specific and selectively induced expression of members of the p24 family of putative cargo receptors.

Members of the p24 family of type I transmembrane proteins are highly abundant in transport vesicles and are thought to be involved in selective protein transport between the endoplasmic reticulum and the Golgi complex. The p24 proteins have been grouped into four subfamilies (alpha, beta, gamma, and delta) and appear to assemble into tetrameric complexes that contain only one representative from each subfamily. Here we molecularly dissected the p24 family in a single cell type, namely in the intermediate pituitary melanotrope cells of the amphibian Xenopus laevis. The biosynthetic activity of these cells for production of their major cargo protein proopiomelanocortin (POMC) can be physiologically manipulated via the process of background adaptation (similar30-fold induction, with highly active cells in black toads and virtually inactive cells in white animals). Extensive cDNA library screening revealed the identity of six p24 proteins expressed in the Xenopus melanotrope cells, namely one member of the p24alpha (alpha(3)), one of the p24beta (beta(1)), two of the p24gamma (gamma(2), gamma(3)) and two of the p24delta (delta(1), delta(2)) subfamily. Two other Xenopus p24 proteins, Xp24alpha(2) and -gamma(1), were not expressed in the melanotrope cells, pointing to cell-type specific p24 expression. Of the six melanotrope p24 proteins, the expression of four (Xp24alpha(3), -beta(1), -gamma(3) and -delta(2)) was 20- to 30-fold induced in active versus inactive melanotropes, whereas that of the other two members (Xp24gamma(2) and -delta(1)) had not or only slightly increased. The four proteins were induced only in the intermediate melanotrope cells and not in the anterior pituitary cells, and displayed similar overall tissue distributions that differed from those of Xp24gamma(1), -gamma(2) and -delta(1). Together, our results reveal that p24 expression can be cell-type specific and selectively induced, and suggest that in Xenopus melanotrope cells an alpha(3)/beta(1)/gamma(3)/delta(2) p24 complex is involved in POMC transport through the early stages of the secretory pathway.

Animals↗
PubMedDate not supplied

A simple and economic slide micro-immunoenzymatic (micro-SIA) test for epidemiological studies of toxoplasmosis.

A slide micro-immunoenzymatic assay (micro-SIA) to detect antibodies to non-particulate Toxoplasma gondii antigens is described. This assay allows the diagnosis of toxoplasmosis infection in about 1 hr. Twenty-four determinations can be performed per slide. Five hundred ng of antigen and 5 or 10 microliters drop of each reactive are necessary per well. The clear contrast of colours obtained for negative and positive sera after the test is finished, allows direct discrimination of the results. However, it is possible to quantify the results of the reaction using a minireader. Sera dilution cutoff value, determined as the most frequent titre for the general population, is 1:100. The toxoplasma micro-SIA correlates well with indirect immunofluorescence (IIF), its sensitivity is at least three times as much as IIF. The test has an intra and inter assay variation coefficient of 5.46% and of 6.24% respectively. Sera obtained at random from argentinian people were analyzed and a 56% of infection was found. The main features of the Toxoplasma micro-SIA are its simplicity, sensitivity, reproducibility, and the virtual absence of background making it very suitable for screening tests.

Animals↗
PubMed2001

[Virtual large intestine imaging with multi-level CT. Pain free coloscopy--that works!].

Provided that the bowel is carefully cleansed, virtual colonoscopy permits a safe, reliable and painfree diagnosis of the large bowel. It requires distension of the bowel with ambient air. Contraindications include pregnancy, acute inflammation of the bowel and recent surgery. Tumors and large polyps (10 mm and more) can be diagnosed with certainty, while polyps measuring 5 mm and more are detected with a high degree of sensitivity. It goes without saying that virtual colonoscopy does not allow for the taking of biopsy material or the performance of therapeutic measures, so that positive or suspicious findings must be clarified by conventional colonoscopy. In principle, virtual colonoscopy is also suitable for use as a screening procedure. Whether the radiation exposure associated with the conventional examination protocol can be considered acceptable for screening purposes is questionable. However, using mathematical means, the radiation dose can be reduced to one-tenth of the usual dose.

Colon↗
PubMed1987

[Hepatitis-related viral markers in patients under long-term hemodialysis].

Antibody profiles for hepatitis B virus (HBV), hepatitis A virus (HAV), cytomegalovirus (CMV), Epstein-Barr virus (EBV) and human immunodeficiency virus (HIV) were determined on 55 serum samples collected from patients with chronic renal failure who were on long-term haemodialysis for periods ranging from 8 months to 5 years and 3 months. The exposure rates for HBV, HAV, CMV, EBV and HIV were 94.5%, 100%, 94.5%, 94.5% and 0% respectively. Among the 7 HBsAg carriers, 1 and 3 were positive for e antigen (HBeAg) and antibody to HBeAg (anti-HBe), respectively and three negative for both. These 7 carriers were also negative for anti-delta antibody. A comparison of the above antiviral profiles to those of voluntary blood donors and general population in this district revealed tht there is no difference for HBV, HAV, CMV and EBV exposure rates, VDRL, alpha-fetoprotein and CEA were also tested and the results showed no abnormalities. Only 3 patients had abnormally elevated SGOT and SGPT levels; the causes were undetermined because all of them gave positive HBV, HAV, CMV and EBV antibody profiles. In conclusion the screening of HBsAg and VDRL in the blood banks virtually eliminated possible infections of HBV and spirochate by blood transfusion and the patients with chronic renal failure who are maintained on long-term haemodialysis are generally not at higher risks of hepatitis-related viral infections.

Adult↗
PubMed1995

Mutagenesis and behavioral screening for altered circadian activity identifies the mouse mutant, Wheels.

The molecular processes underlying the generation of circadian behavior in mammals are virtually unknown. To identify genes that regulate or alter circadian activity rhythms, a mouse mutagenesis program was initiated in conjunction with behavioral screening for alterations in circadian period (tau), a fundamental property of the biological clock. Male mice of the inbred BALB/c strain, treated with the potent mutagen N-ethyl-N-nitrosourea were mated with wild-type hybrids. Wheel-running activity of approximately 300 male progeny was monitored for 6-10 weeks under constant dark (DD) conditions. The tau DD of a single mouse (#187) was longer than the population mean by more than three standard deviations (24.20 vs. 23.32 +/- 0.02 h; mean +/- S.E.M.; n = 277). In addition, mouse #187 exhibited other abnormal phenotypes, including hyperactive bi-directional circling/spinning activity and an abnormal response to light. Heterozygous progeny of the founder mouse, generated from outcrossings with wild-type C57BL/6J mice, displayed lengthened tau DD although approximately 20% of the animals showed no wheel-running activity despite being quite active. Under light:dark conditions, all animals displaying circling behavior that ran in the activity wheels exhibited robust wheel-running activity at lights-ON and these animals also showed enhanced wheel-running activity in constant light conditions. The genetic dissection of the complex behavior associated with this mutation was facilitated by the previously described genetic mapping of the mutant locus causing circling behavior, designated Wheels (Whl), to the subcentromeric portion of mouse chromosome 4. In this report, the same locus is shown to be responsible for the abnormal responses to light and presumably for the altered circadian behavior. Characterization of the gene altered in the novel Whl mutation will contribute to understanding the molecular elements involved in mammalian circadian regulation.

Animals↗
PubMed2006

Screening for substance use patterns among patients referred for a variety of sleep complaints.

Virtually all psychiatric and substance use disorders are associated with sleep disruption. Studies indicate that psychiatric disorders are related closely to chronic insomnia and that psychoactive substances have acute and chronic effects on sleep architecture. Several aspects of sleep are compromised in individuals taking these substances, ranging from difficulty initiating sleep to difficulty maintaining sleep and hypersomnia. Sleep disturbances are apparent in person taking psychoactive drugs or alcohol and have been found to persist long after withdrawing from these drugs. For some, sleep disturbance can be so severe as to reverse treatment success and precipitate relapse to addiction or dependence. There is increasing evidence that primary insomnia without a concurrent psychiatric disorder is a risk factor for later developing substance use disorders. Patients were asked to complete two brief screening tools, the Michigan Alcohol Screening Test and Drug Abuse Screening Test, to examine substance use patterns among patients referred for a variety of sleep complaints in a sleep disorders clinic. We found that patients who demonstrated a variety of sleep complaints were more likely to have alcohol and drug problems than those in the general populations.

Acute Disease↗
PubMed2002

STD screening, testing, case reporting, and clinical and partner notification practices: a national survey of US physicians.

OBJECTIVES: This study presents results from a national survey of US physicians that assessed screening, case reporting, partner management, and clinical practices for syphilis, gonorrhea, chlamydia, and HIV infection. METHODS: Surveys were mailed to a random sample of 7300 physicians to assess screening, testing, reporting, and partner notification for syphilis, gonorrhea, chlamydia, and HIV. RESULTS: Fewer than one third of physicians routinely screened men or women (pregnant or nonpregnant) for STDs. Case reporting was lowest for chlamydia (37 percent), intermediate for gonorrhea (44 percent), and higher for syphilis, HIV, and AIDS (53 percent-57 percent). Physicians instructed patients to notify their partners (82 percent-89 percent) or the health department (25 percent-34 percent) rather than doing so themselves. CONCLUSIONS: STD screening levels are well below practice guidelines for women and virtually nonexistent for men. Case reporting levels are below those legally mandated; physicians rely instead on patients for partner notification. Health departments must increase collaboration with private physicians to improve the quality of STD care.

Adult↗
PubMedDate not supplied

Current and future trends in colorectal cancer screening.

Current modalities for colorectal cancer screening include fecal occult-blood testing, flexible sigmoidoscopy, colonoscopy, and double-contrast barium enema. Among these, colonoscopy is becoming the dominant modality, in light of its efficacy and continuing technical refinements. Emerging technologies, such as stool DNA tests and virtual colonoscopy, hold promise for the future but cannot be recommended for screening at present.

Barium Sulfate↗
PubMed2003

Encoding microcarriers by spatial selective photobleaching.

Bead-based assays on very large numbers of molecules in gene expression studies, drug screening and clinical diagnostics, require the encoding of each of the microspheres according to the particular ligand bound to its surface. This allows mixing the uniquely encoded microspheres and subjecting them to an assay simultaneously. When a particular microsphere gives a positive reaction, the substance on its surface can be identified by reading the code. Previously reported techniques for colour encoding polymer microspheres only allow for a limited number of unique codes. Graphical encoding methods use metallic particles, which are rather uncommon in screening applications. Here, we demonstrate a new approach to encode polymer microspheres that are commonly used in screening applications, such as polystyrene microspheres, with a method that provides a virtually unlimited number of unique codes. Patterns can be written in fluorescently dyed microspheres by 'spatial selective photobleaching' and can be identified by confocal microscopy. Such encoded microparticles can find broad application in the collection and analysis of genetic information, high-throughput screening, medical diagnostics and combinatorial chemistry, and can also be used for labelling of consumer goods or as security labels to prevent counterfeiting.

Microspheres↗
PubMed2005

[Early diagnosis of colorectal tumors].

Colorectal cancer (CRC) is one of the most common causes of cancer mortality in Western countries. Approximately six percent of the population will develop colorectal cancer during life. Individuals older than 50 years or with a family history for colorectal tumors as well as patients with an inflammatory bowel disease have an increased risk for CRC. A significant reduction of colorectal cancer mortality can be achieved by screening of asymptomatic patients and removal of premalignant adenomatous polyp precursors. Colonoscopy is recognized as the gold standard, but in future virtual colonoscopy might be a reasonable addition. Asymptomatic individuals with an average risk for CRC should be screened from the age of 50 and then every 10 years if the examination showed no pathological findings. When the individual or family history indicate a higher risk for a colorectal neoplasia, screening should begin at the age of 40 or 10 years before the earliest tumor occurrence in the family. Families with hereditary CRC require a special surveillance.

Chronic Disease↗