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PubMed2001

Attentional selection and the processing of task-irrelevant information: insights from fMRI examinations of the Stroop task.

In this chapter, we discuss our research that reveals how attentional mechanisms can modulate activity of posterior brain regions responsible for processing the unattended attribute of a stimulus. To do so, we utilized fMRI to reveal patterns of regional brain activity for variants of the Stroop task that differ in the nature of the task-irrelevant stimulus attribute. In all variants, individuals had to identify the ink color in which an item was presented. To vary attentional demands, we manipulated whether or not the task-irrelevant information contained conflicting color information. The variants differed in whether the conflicting color information was contained in a word naming a color (e.g. the word 'red' in blue ink), a word naming an object highly associated with a specific color (e.g. the word 'frog' in red ink), or a line drawing of an object highly associated with a specific color (e.g. a drawing of a frog in red ink). When the unattended stimulus attribute contained color information that conflicted with an item's ink color, increased activity was observed in the posterior brain region that processes the aspect of the task-irrelevant attribute related to color. Increased activity was observed in the left precuneus and left superior parietal cortex when the conflicting information arose from a color word; in the middle temporal gyrus and insular cortex when the word named an object highly associated with a specific color, and included extensive regions of early portions of the ventral visual processing stream when a line drawing was highly associated with a specific color. These areas have been implicated in word processing, semantic processing, and visual processing, respectively. Our results suggest that attentional selection can occur by: (1) increasing the gain on all posterior regions responsible for processing information related to the task demands, regardless of whether that information is contained in the task-relevant or task-irrelevant dimension; (2) limiting the processing of task-irrelevant information in order to reduce interference; and (3) modulating the processing of representations varying from those of a low-level perceptual nature up through those of a higher-order semantic nature.

Adult↗
PubMed2000

Benign prostatic glands at surgical margins of radical prostatectomy specimens: frequency and associated risk factors.

OBJECTIVES: Elevation of serum prostate-specific antigen (PSA) after radical prostatectomy for prostate cancer is considered a surrogate marker of therapeutic failure. The most likely explanation for early PSA failure is considered to be due to local recurrent disease, provided the patient had a nondetectable PSA level after radical prostatectomy. Others have recently suggested that benign prostatic glands located on the surgical margins may often lead to detectable PSA levels. We examined the frequency of benign prostatic glands at the surgical margins of radical prostatectomy specimens and the factors associated with this finding. METHODS: One hundred nineteen consecutive radical prostatectomies were performed by two experienced oncologic surgeons. Whole-mount sectioning of the prostatectomy specimens was performed at 3-mm intervals. Bivariate and multivariate analyses were used to determine which clinical and pathologic factors were associated with benign glands on inked surgical margins. RESULTS: Of the 119 cases, 13 (11%) had benign glands on the inked surgical margins. Four of these 13 had tumor on the inked margins. The remaining 9 cases (8%) were organ confined (pT2), with negative surgical margins. Benign glands were most often seen to involve the apex focally (7 of 9 cases). On bivariate and multivariate analyses, a high Gleason score and prostate gland volume were significantly associated with finding benign glands on the surgical margins. Only 2 of 86 patients with follow-up had PSA recurrence at 59 and 67 days and neither had benign glands on the inked surgical margins. CONCLUSIONS: The presence of benign prostatic glands identified on inked surgical margins was an infrequent occurrence in this consecutive series of 119 whole-mount prostatectomy specimens. When benign glands were identified, they most often consisted of 1 to 3 glands at the apex margin. These findings suggest that benign glands on surgical margins are an unusual cause of postoperative detectable PSA.

Follow-Up Studies↗
PubMed1993

Leakage evaluation with and without vacuum of two gutta-percha fill techniques.

Two sets of 30 roots were obturated either with lateral condensation or a halothane dip technique. Fifteen roots from each group were immersed in India ink with vacuum and 15 without vacuum. Each root was coated with nail polish and wax, leaving only its apical end open for ink penetration. The roots were cleared and three linear measurements were made: distance of ink penetration coronal to the gutta-percha apical tip; distance from the gutta-percha tip to major foramen; and distance from the major foramen to anatomical apex. The average length of ink penetration coronal to the apical extension of the gutta-percha for the lateral condensation groups combined was 1.33 mm and for the halothane groups combined was 2.15 mm. There was no significant difference between vacuumed and not vacuumed for degree of ink penetration. The gutta-percha of the halothane-dipped groups advanced significantly closer to the foramen than the lateral condensation groups (0.38 mm versus 0.65 mm).

Cuspid↗
PubMed2002

A new method for the investigation of capillary structure.

Numerous physiological conditions as well as behavioral conditions have been shown to influence central nervous system vascular structure. Many of the methods used to investigate these structural alterations take advantage of the visibility of viscous substances (e.g. India ink in gelatin) perfused into the vasculature. The high viscosity of the solution, however, can cause incomplete vessel perfusion. The aim of the present study was to test whether or not capillaries seen in tissue perfused with fixative, embedded in celloidin and stained with Methylene Blue-Azure II (n=6) could be a useful alternative for the investigation of brain vascular structure. The method was compared to tissue from six rats perfused with India ink in gelatin and stained with cresyl violet. Qualitatively, vessels in the standard perfused tissue embedded in celloidin yielded clear vessels with stained pericytes. The two methods did not differ in branch point to cell ratio, length of individual capillaries, vessel length per mm(3), and capillary tortuosity. The capillary diameter was greater in the celloidin embedded tissue than in the India ink perfused tissue. Measuring the diameter between vessel walls appears to provide a more accurate measure than the widest distance between India ink pigments. Quantitative comparisons suggest that perfusion with standard fixative followed by embedding in celloidin provides vascular quantification comparable to that from India ink perfused tissue. The present method has several advantages, which include visualization of pericytes, increased probability of complete perfusion, clear view of cells that might otherwise be obscured by opaque vessels, and the possibility of using the alternate cerebral hemisphere for investigation of vascular ultrastructure.

Animals↗
PubMed1995

Experimental observation of particulate flow along cranial nerves.

The purpose of this study was to investigate the communicative routes via the cranial nerves among the middle ear, the auditory tube, the inner ear, and the subarachnoid space under nearly physiological conditions. Various volumes of Indian ink were slowly injected into the facial nerve trunk of rabbits at the stylomastoid foramen, then serial sections of the heads were observed under the light microscope. This study yielded the following results: (i) Indian ink penetrated into the subarachnoid space through the internal auditory canal and/or the jugular foramen along the nerve sheaths of the VIIth, IXth, and/or Xth cranial nerves. (ii) Indian ink penetrated through the nerve sheaths of the cochlear, superior vestibular, and inferior vestibular nerves to the fundus of the internal auditory canal. (iii) Indian ink reached the scala tympani and the scala vestibuli via the cochlear aqueduct. (iv) Indian ink penetrated to the nerve sheaths of the tensor tympani and/or tensor palati nerves from the subarachnoid space of the trigeminal ganglion. In conclusion, it was shown that certain small particles are able to penetrate from the facial nerve sheath at the entrance of the stylomastoid foramen to the VIIIth, IXth, and Xth nerve trunks, the middle ear, the area around the auditory tube, the inner ear, and the subarachnoid space.

Animals↗
PubMed2005

Diffusion of alkanethiols in PDMS and its implications on microcontact printing (muCP).

n-Alkanethiols HS-(CH2)n-CH3 such as hexadecanethiol (HDT, n = 15), octadecanethiol (ODT, n = 17), and eicosanethiol (ECT, n = 19) have been shown to provide highly protective etch resists on microcontact-printed noble metals. As the quality of the printed pattern strongly depends on the mobility of the ink compound, we focused on understanding the diffusion behavior of HDT, ODT, and ECT in poly(dimethylsiloxane) (PDMS) stamps. We used a commercial PDMS material (Sylgard184), which is commonly used for microcontact printing (muCP), and a custom-synthesized one with a higher modulus. On the basis of linear-diffusion experiments, which maintained realistic printing conditions, we showed that the ink transport in the stamp follows Fick's law of diffusion. We then determined the diffusion coefficient by analytical and numerical modeling of the diffusion experiments. Numerical calculations were carried out with the finite-difference method applying more realistic boundary conditions (ink adsorption). Values for the diffusion coefficients of the three ink compounds in the two different PDMS materials all are on the order of (4-7) x 10(-7) cm2 s(-1). The scope and limits of the mathematical models are discussed. To demonstrate the potential of such models for microcontact printing, we simulate multiple printing cycles of an inked stamp and compare the results with experimental data.

Journal Article↗
PubMed2004

Spreading of 16-mercaptohexadecanoic acid in microcontact printing.

Spreading in microcontact printing refers to the process or processes by which the ink molecules end up in the parts of the substrate that are adjacent to the contacted areas but which are not contacted themselves. This has been investigated for different inking concentrations of 16-mercaptohexadecanoic acid (MHDA). Spreading of MHDA takes place with retention of a well-defined demarcation. Feature sizes can be controlled by varying the contact times. Spreading, however, only takes place beyond a certain threshold concentration. For low ink concentrations the edges of stamp features dominate the ink transfer. For these low concentrations the extent of this edge dominance depends strongly on ink concentration rather than on contact time. These observations indicate a dominant role of the stamp surface in the processes of pattern formation and spreading.

Journal Article↗
PubMed2000

Structural evidence for counter-current flow in proximal tubules versus pertitubular capillaries in the rat kidney. Evaluation of the counter-current mechanism between the proximal convoluted tubules and the peritubular capillaries in the rat nephron.

BACKGROUND: In spite of the very high exchange of water and solutes between the proximal tubules and the peritubular capillaries, very little is known about flow directions in these two interrelated structures. We therefore developed a morphological technique suitable for the quantitative evaluation of a counter-current system between the proximal convoluted tubules and the peritubular capillaries in rat renal cortex. METHODS: In male pentothal-anesthetized Wistar rats (body weight 200-250 g), India ink was injected into the aorta above the renal arteries, followed by instant freezing of the right kidney in isopentane at -165 degrees C, and subsequent freeze-substitution in alcohol. In microscopic slides from kidneys in which only 20-55% of the cortical peritubular capillary loops was filled with ink--representing the arterial end of the capillaries--and in which the proximal tubular segmentation could be identified in PAS-stained sections, the segments of the convoluted proximal tubules were quantitatively compared with regard to the presence of ink-stained and unstained peritubular capillaries in nephrons from the whole renal cortex. RESULTS: In the microscopic specimens of the five animals used both the loops from the first segment (P1) of the proximal convoluted tubule and those of the second segment (P2) were systematically packed closely together, the transitional segment (P1-2) being interposed between the groups. Around the loops of P1, 8%+/-2% of the capillaries was stained with India ink. In contrast, surrounding the P2 loops 67%+/-5% of the capillaries contained ink, significantly exceeding that for P1 (p<0.01). CONCLUSION: Throughout the rat renal cortex, the most proximal fraction of the peritubular capillaries surrounds the second segments of the proximal convoluted tubules, while the first tubular segments are surrounded by the more distal fraction of the peritubular capillaries. Consequently, the flows in the peritubular capillaries and in the proximal convoluted tubules in the rat renal cortex are systematically arranged as a counter-current system. This feature was previously identified only in superficial nephrons.

Animals↗
PubMed1995

Identification and characterization of a functional retinoic acid/thyroid hormone-response element upstream of the human insulin gene enhancer.

A deletion analysis of the human insulin gene extending to 2 kb upstream of the transcription start site provided evidence of regulatory sequences located upstream of the insulin-linked polymorphic region (ILPR). Within this ILPR-distal region is a sequence (Ink, for insulin kilobase upstream) which contains three potential nuclear hormone-receptor half-sites, closely matching the consensus sequence AGGTCA. These sequences are arranged as a palindromic element with zero spacing over-lapping a direct repeat with 2 bp spacing. The Ink sequence was used in electrophoretic mobility-shift assays within nuclear extracts from COS-7 cells overexpressing the vitamin D, thyroid hormone or retinoic acid receptors, or from an insulin-expressing hamster cell line, HIT-T15. These studies suggest that the insulin-expressing cell line contains thyroid hormone and retinoic acid receptors at least, and that these receptors are able to recognize the Ink sequence. Three copies of the Ink sequence were placed upstream of the thymidine kinase promoter and firefly luciferase reporter gene. In COS-7 cells expressing the appropriate nuclear hormone receptor, this construct was responsive to both thyroid hormone (18-fold) and all-trans-retinoic acid (31-fold). In HIT-T15 cells the same construct responded to all-trans-retinoic acid, but not to thyroid hormone. Within the context of a 2 kb insulin gene fragment, the Ink sequence was shown to be activated by retinoic acid and by the retinoic acid receptor, but acted as a negative element in the presence of both retinoic acid and the retinoic acid receptor. Mutagenesis studies demonstrated that the palindromic sequence was important for the retinoic acid response, and for binding of complexes containing retinoic acid receptor. In human islets of Langerhans, retinoic acid was shown to stimulate insulin mRNA levels. These results demonstrate that a functional nuclear hormone-receptor-response element is located upstream of the human ILPR. As retinoic acid and thyroid hormone are frequently involved in developmental regulatory processes, it is possible that this element may be important in the process of islet cell differentiation.

Animals↗
PubMed2006

Evidence of meniscus interface transport in dip-pen nanolithography: An annular diffusion model.

Ring shaped dots were patterned with mercaptohexadecanoic acid ink by dip-pen nanolithography. These dots have an ink-free inner core surrounded by an inked annular region, making them different from the filled dots usually obtained. This suggests a different transport mechanism than the current hypothesis of bulk water meniscus transport. A meniscus interface ink transport model is proposed, and its general applicability is demonstrated by predicting the patterned dot radii of chemically diverse inks.

Journal Article↗
PubMed2000

Study of cerebrospinal fluid flow dynamics in TGF-beta 1 induced chronic hydrocephalic mice.

In a previous study, we found that the CSF level of transforming growth factor beta 1 (TGF-beta 1) is elevated following subarachnoid hemorrhage (SAH) in patients who later develop communicating hydrocephalus, while in mice, an intrathecal injection of TGF-beta 1 can induce communicating hydrocephalus. Recently, histopathological changes in the leptomeninges were studied using the above TGF-beta 1 induced mice model of hydrocephalus. In the present study, in order to further clarify the ventricular dilatation mechanism, we examined cerebrospinal fluid (CSF) flow dynamics in TGF-beta 1 induced hydrocephalic mice. To assess CSF flow, Indian ink was injected into the passage pathway and the time taken for the ink to pass from the parietal intrameningeal CSF space to cervical lymph nodes was determined. The ink study revealed a significant lengthening of the ink passage time due to altered CSF flow dynamics, while a histological examination showed ink stasis in the altered leptomeningeal CSF space compared to PBS injected control mice. TGF-beta 1 induced increased cellularity in the leptomeninx and fibrosis, and a subsequent narrowing of the intrameningeal CSF space. This narrowing causes a disturbance in CSF flow, thus generating a mild pressure gradient, which ultimately leads to the development of slowly progressive ventricular dilatation. After SAH, elevated TGF-beta 1 in the CSF may play a similar role, in concert with other factors, in the development of communicating hydrocephalus in human.

Animals↗
PubMed1997

Color-Word Stroop test performance across the adult life span.

In the Color-Word Stroop test (CWST), the basic task is to name the ink color of rows of XXXs, and performance in this condition is compared with performance in naming the ink-color of color words under conditions where word meanings and ink colors mismatch or are incongruent (e.g., the word red printed in green ink). The present study investigated whether Stroop test interference, defined as the cost associated with ink-color naming in the incongruous stimulus condition versus in the basic color-naming condition, provides positive evidence for a kind of processing qualitatively different than that which is required for color naming or for word reading. Does the pattern of age-related differences in Stroop interference force the conclusion that the incongruous condition taps a qualitatively different kind of processing than that required for color naming or for word reading? We gave the CWST to 310 healthy adults. Their performance in each condition of the test replicates and extends previous findings. Structural equation modeling of the data showed a significant, direct link between age and performance in the latent factor associated with the incongruent condition. However, this direct link with age produced a relatively small increase in the model's fit; it amounted to only a .024 increase in the proportion of variance explained in the incongruent condition. In light of this small direct influence due to age, the most parsimonious explanation of our findings is that age effects in Stroop interference are due to age-related slowing (which is also indexed by color naming and by word reading) primarily; the findings do not provide evidence for a qualitatively different kind of processing that declines with age.

Adolescent↗
PubMed1999

Effects of copper vapor laser irradiation in human enamel and dentin: ablation and morphological studies.

OBJECTIVE: This investigation was performed to determine the ranges of ablation quantitatively and to evaluate the morphological changes in human enamel and dentine irradiated by a green copper vapor laser. SUMMARY BACKGROUND DATA: Recently, green copper vapor laser (CVL), which is said to have characteristics similar to the argon laser has been introduced in dentistry. METHODS: Extracted noncarious human teeth were used in this study. A CVL was used to ablate human dental hard tissues with the output powers of 2.0 W. Ablation extent without water spray using red or black ink was measured, and the morphological changes on enamel and dentin were also investigated by stereoscopy and scanning electron microscopy (SEM). RESULTS: In the samples, irradiated by a CVL after painting red ink on the surface, the ablation depth was increased more than that of irradiation after painting with black ink. Morphological findings by SEM indicated that when irradiated with red ink, brown carbonization was recognized on enamel and dentin surfaces. In addition, cavities with a molten lava-like appearance were produced and an irregular structure with many microholes was observed in the enamel and dentin. Alternatively, a shallow cavity with little carbonization was produced with black ink. CONCLUSIONS: Removal of dental hard tissues appears to be possible using the CVL. However, further studies should be performed on the selection of radiation conditions that achieve the desired ablation with minimal side effects.

Copper↗
PubMed1999

A comparative study on the effects of three types of laser irradiation at the apical stop and apical leakage after obturation.

OBJECTIVE: The purposes of this study were to determine the degree of apical leakage using a dye penetration method after argon, pulsed Nd:YAG with or without black ink, or Er:YAG laser treatment and obturation, and to compare the results of three types of laser irradiation in vitro. SUMMARY BACKGROUND DATA: There have been only a few reports of the laser effect on apical leakage after laser treatment and obturation. METHODS: Seventy-five human extracted single root teeth were divided into five groups of 15 teeth each and prepared up to a #60 K-file size. One group served as the control and was not irradiated. The other four groups were irradiated with an argon laser at 0.3 W for 3 seconds at continuous mode, pulsed Nd:YAG laser at 2 W and 20 Hz for 4 seconds with or without black ink, and Er:YAG laser at 50 mJ per pulse and 4 Hz for 5 seconds. In each group, ten teeth for the apical leakage study were obturated and immersed in rhodamine B solution for 48 hours at 37 degrees C, and the others were used for the observation by scanning electron microscopy (SEM). All teeth were longitudinally bisected and observed by stereoscopy or SEM. RESULTS: After pulsed Nd:YAG laser treatment with black ink and obturation, the apical leakage degree (mean score: 0) was reduced compared to that in the control (mean score: 1.2) significantly (p < 0.05). SEM findings showed that specimens irradiated by pulsed Nd:YAG laser with black ink presented clean root canal walls with debris and smear layer evaporated, melted, fused, and recrystallized in most cases. CONCLUSION: These results suggest that pulsed Nd:YAG laser irradiation with black ink at the apical stop is useful for the reduction of apical leakage after obturation.

Dental Leakage↗
PubMed1996

Endoscopic tattoo agents in the colon. Tissue responses and clinical implications.

Laparoscopic surgery frequently requires tattooing of endoscopically identified sites for localization during surgery. Some tattooing agents cause serious tissue injury, which must be recognized in pathologic examination. Seven surgically resected colons were reviewed after injection with methylene blue or India ink at intervals of 1 day to 7 weeks before surgery. Early reactions to India ink included necrosis, edema, and neutrophilic infiltration in the submucosa and muscularis propria. Vessels were inflamed but without fibrinoid necrosis. Early reactions to methylene blue included ischemic ulceration, necrosis, and eosinophilic infiltration in the submucosa as well as fibrinoid necrosis of vessel walls. In the repair of methylene-blue injury, obliterative intimal fibrosis was seen in vessels. Such changes were absent in the colons injected with India ink. The India ink remained remained visible with the naked eye and microscopically 7 weeks after injection. Methylene blue was not grossly visible 7 days after injection, and only microscopic particles of pigment remained in widely scattered macrophages. In light of these findings, the amount of ink injected should be minimized and the injection site should be completely resected at surgery. Methylene blue is a poor tattoo agent, but its occasional use continues, and pathologists should recognize the resulting reaction.

Adipose Tissue↗
PubMed1993

CSF drains directly from the subarachnoid space into nasal lymphatics in the rat. Anatomy, histology and immunological significance.

Cerebrospinal fluid (CSF) drainage pathways from the rat brain were investigated by the injection of 50 microliters Indian ink into the cisterna magna. The distribution of the ink, as it escaped from the cranial CSF space, was documented in 2 mm thick slices of brain and skull cleared in cedar wood oil and in decalcified paraffin sections. Following injection of the ink, deep cervical lymph nodes were selectively blackened within 30 min and lumbar para-aortic nodes within 6 h. Within the cranial cavity, carbon particles accumulated in the basal cisterns but were also distributed in the paravascular spaces around the middle cerebral arteries and the nasal-olfactory artery. Carbon particles in the subarachnoid space beneath the olfactory bulbs drained directly into discrete channels which passed through the cribriform plate and into lymphatics in the nasal submucosa. Although ink was distributed along the subarachnoid space of the optic nerves and entered the cochlea, the nasal route was the only direct connection between cranial CSF and lymphatics. Arachnoid villi associated with superior and inferior sagittal sinuses were identified and a minor amount of drainage of ink into dural lymphatics was also observed. This study demonstrates the direct drainage of cerebrospinal fluid through the cribriform plate in anatomically defined channels which connect with the nasal lymphatics.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Clinical use of the Q-switched ruby and the Q-switched Nd:YAG (1064 nm and 532 nm) lasers for treatment of tattoos.

BACKGROUND: The desire to remove tattoos has probably been around as long as their existence. Recent technological advances in lasers have finally made it possible to remove tattoos without leaving an equally undesirable scar. OBJECTIVE: The purpose of this article is to review the use of the Q-switched ruby (694 nm) and the Q-switched Nd:YAG (532 and 1064 nm) lasers for effective removal of tattoo ink, with cosmetically appealing results. RESULTS: The Q-switched ruby laser (694 nm) effectively removes blue-black and green ink, may treat other colors less efficiently, and is frequently associated with transient pigmentary changes, including rare depigmentation. The Q-switched Nd:YAG laser at 1064 nm quickly removes black ink, as well as other colors less efficiently; pigmentary changes are much less frequent, correlating with its lower absorption by melanin. The 532-nm wavelength treats red ink effectively, but also leads to temporary hypopigmentation. Transient textural changes may be noted at all three wavelengths discussed, but scarring is rare. CONCLUSIONS: Q-switched lasers can remove tattoos without residual scarring. Efficacy of ink removal is dependent on the wavelength used for the targeted pigment.

Adult↗
PubMed2006

A simple microthermal desorption device.

A new method for thermal desorption of small samples is presented. The method uses a solid phase microextraction (SPME) holder with the fiber removed. The sample-for example, an ink sample on paper-is simply placed inside the needle of the holder, where normally an SPME fiber is positioned. The thermal desorption is then performed on any kind of gas chromatograph in a manner similar to that for SPME analysis. The needle of the SPME holder penetrates the injector septum; the temperature of the thermal desorption is simply the temperature of the injector. No solvents or liquid nitrogen cooling are used. The paper sample is kept inside the holder needle during the analysis. After the analysis is completed, the sample is removed from the needle by pushing forward the steel wire inside the needle in the way normally used to perform sampling with the SPME fiber. The desorbed compounds were analyzed by gas chromatography with a flame ionization detector or by gas chromatography-mass spectrometry. The optimum temperature for desorption of ink samples on paper was 200 degrees C. The influence of the paper matrix is negligible at that temperature. Laboratories lacking the commercial device for thermal desorption can use this cheap device for the analysis of, for example, writing ink, printing ink, and inkjet ink samples on paper. Other types of samples can be investigated but the size of samples suitable for analysis is limited.

Journal Article↗