On the relative influence of individual harmonics on pitch judgment

Spectral weighting functions were estimated in a pitch-comparison task to assess the relative influence of individual harmonics on listeners' pitch judgment. The stimuli were quasi-harmonic complex tones composed of the first 12 components, with fundamental frequencies ranging from 100 to 800 Hz. On each stimulus presentation the frequency of each harmonic was randomly jittered by a small amount. The perceptual weight for each harmonic was calculated as the correlation coefficient between the binary responses of the listener and the frequency jitters for that harmonic. Although in general the present results conform to previous ones showing the predominant role of several low-ranked harmonics, discrepancies exist in details. Contrary to some previous reports that the dominant harmonics were of fixed harmonic ranks regardless of their frequencies, the current results showed that the dominant harmonics were best described as close to a fixed absolute frequency of 600 Hz.

[Molecular cytogenetics study in a case with unbalanced chromosome translocation]

OBJECTIVE

To analyze the chromosome structural aberration in a case of unbalanced chromosome translocation by fluorescence in situ hybridization technique.

METHODS

The 1,18 whole chromosome specific painting probe were used to confirm chromosome abnormality suggested by high resolution G-banding examination.

RESULTS

An unbalanced translocation t(1;18)(q42;q22) was detected in the patient, which caused partial trisomy of 1q42-qter and partial monosomy of 18q22-qter.

CONCLUSION

The identified translocation suggested a potential site for congenital heart disease.

Nanotube molecular wires as chemical sensors

Chemical sensors based on individual single-walled carbon nanotubes (SWNTs) are demonstrated. Upon exposure to gaseous molecules such as NO(2) or NH(3), the electrical resistance of a semiconducting SWNT is found to dramatically increase or decrease. This serves as the basis for nanotube molecular sensors. The nanotube sensors exhibit a fast response and a substantially higher sensitivity than that of existing solid-state sensors at room temperature. Sensor reversibility is achieved by slow recovery under ambient conditions or by heating to high temperatures. The interactions between molecular species and SWNTs and the mechanisms of molecular sensing with nanotube molecular wires are investigated.

PSM, a mediator of PDGF-BB-, IGF-I-, and insulin-stimulated mitogenesis

PSM/SH2-B has been described as a cellular partner of the FcepsilonRI receptor, insulin receptor (IR), insulin-like growth factor-I (IGF-I) receptor (IGF-IR), and nerve growth factor receptor (TrkA). A function has been proposed in neuronal differentiation and development but its role in other signaling pathways is still unclear. To further elucidate the physiologic role of PSM we have identified additional mitogenic receptor tyrosine kinases as putative PSM partners including platelet-derived growth factor (PDGF) receptor (PDGFR) beta, hepatocyte growth factor receptor (Met), and fibroblast growth factor receptor. We have mapped Y740 as a site of PDGFR beta that is involved in the association with PSM. We have further investigated the putative role of PSM in mitogenesis with three independent experimental strategies and found that all consistently suggested a role as a positive, stimulatory signaling adapter in normal NIH3T3 and baby hamster kidney fibroblasts. (1) PSM expression from cDNA using an ecdysone-regulated transient expression system stimulated PDGF-BB-, IGF-I-, and insulin- but not EGF-induced DNA synthesis in an ecdysone dose-responsive fashion; (2) Microinjection of the (dominant negative) PSM SH2 domain interfered with PDGF-BB- and insulin-induced DNA synthesis; and (3) A peptide mimetic of the PSM Pro-rich putative SH3 domain-binding region interfered with PDGF-BB-, IGF-I-, and insulin- but not with EGF-induced DNA synthesis in NIH3T3 fibroblasts. This experiment was based on cell-permeable fusion peptides with the Drosophila antennapedia homeodomain which effectively traverse the plasma membrane of cultured cells. These experimental strategies independently suggest that PSM functions as a positive, stimulatory, mitogenic signaling mediator in PDGF-BB, IGF-I, and insulin but not in EGF action. This function appears to involve the PSM SH2 domain as well as the Pro-rich putative SH3 domain binding region. Our findings support the model that PSM participates as an adapter in various mitogenic signaling mechanisms by linking an activated (receptor) phospho-tyrosine to the SH3 domain of an unknown cellular partner.

[Influence of pavulon on facial nerve monitoring during middle ear-mastoid operation]

OBJECTIVE

To evaluate the influence of pavulon (muscle relaxant) on facial nerve monitoring for patient with middle ear-mastoid operation during general anesthesia.

METHOD

Intraoperative monitoring of the facial nerve (FNM) was done in 45 ears (44 case). For patient with middle ear-mastoid disease, 38 ears underwent inhaled-intravenous anesthesia with muscle relaxant pavulon (group of general anesthesia), 7 ears underwent local anesthesia (group of local anesthesia). Accelography (ACCG) was used in 10 case for testing the correlation between of FNM and the various degree of recovery from ulnar nerve-musculor blockade.

RESULT

FNM could be elicited during different periods of recovery with values of T4/T1 varying from 10%-98%. Pavulon could be used to eliminate muscular vibration from disturbing FNM. Electromyography (EMG) potentials were successfully recorded in 34 ears (89.4%). Anesthesia was uneventful and it may be controled satisfactority.

CONCLUSION

Considering the advantage of pavulon. It can be used for general anesthesia during intraoperative monitoring of the facial nerve for children or adults suffering from local complicated diseases.

Gate-Controlled Superconducting Proximity Effect in Carbon Nanotubes

The superconducting proximity effect in single-walled carbon nanotubes connected to niobium electrodes was controlled with the use of nearby gates that tune the niobium-nanotube transparency. At 4.2 kelvin, when the transparency was tuned to be high, a dip in the low-bias differential resistance was observed, indicating a proximity effect mediated by Andreev reflection. When the transparency was tuned to be low, signatures of Andreev reflection disappeared and only tunneling conduction was observed. Below approximately 4 kelvin, a narrow peak in differential resistance around zero bias appeared superimposed on the Andreev dip, probably as a result of electron-electron interaction competing with the proximity effect.

The polyamine oxidase inhibitor MDL-72,527 selectively induces apoptosis of transformed hematopoietic cells through lysosomotropic effects

Polyamine oxidase functions in the polyamine catabolic pathway, converting N1-acetyl-spermidine and -spermine into putrescine (Put) and spermidine (Spd), respectively, thereby facilitating homeostasis of intracellular polyamine pools. Inhibition of polyamine oxidase in hematopoietic cells by a specific inhibitor, N,N'-bis(2,3-butadienyl)-1,4-butanediamine (MDL-72,527), reduces the levels of Put and Spd and induces the accumulation of N1-acetylated Spd. Although previously thought to be relatively nontoxic, we now report that this inhibitor overrides survival factors to induce cell death of several immortal and malignant murine and human hematopoietic cells, but not of primary myeloid progenitors. Cells treated with MDL-72,527 displayed biochemical changes typical of apoptosis, and cell death was associated with the down-regulation of the antiapoptotic protein Bcl-X(L). However, enforced overexpression of Bcl-X(L), or treatment with the universal caspase inhibitor zVAD-fmk, failed to block MDL-72,527-induced apoptosis in these hematopoietic cells. Despite decreases in Put and Spd pools, MDL-72,527-induced apoptosis was not blocked by cotreatment with exogenous Put or Spd, nor was it influenced by overexpression or inhibition of the polyamine biosynthetic enzyme ornithine decarboxylase. Significantly, MDL-72,527-induced apoptosis was associated with the rapid formation of numerous lysosomally derived vacuoles. Malignant leukemia cells were variably sensitive to the lysosomotropic effects of MDL-72,527, yet pretreatment with the ornithine decarboxylase inhibitor L-alpha-difluoromethylornithine sensitized all of these leukemia cells to the deleterious effects of the inhibitor by stimulating its intracellular accumulation. The lysosomotropic nature of select polyamine analogues may, thus, provide a novel chemotherapeutic strategy to selectively induce apoptosis of malignant hematopoietic cells.

[CAG trinucleotide mutation detection in patients with hereditary spinocerebellar ataxia]

OBJECTIVE

To assess the frequency of the SCA1, SCA2,SCA3/MJD, SCA6, SCA7 and DRPLA CAG trinucleotide repeat expansions(CAG)n among individuals diagnosed with hereditary spinocerebellar ataxia(SCA) from Chinese families.

METHODS

The SCA1, SCA2, SCA3/MJD, SCA6, SCA7 and DRPLA(CAG)n mutations were detected by polymerase chain reaction (PCR), denaturing polyacrylamide gel electrophoresis and silver staining technique in 167 patients with autosomal dominant SCA from 85 Chinese families and 37 sporadic SCA patients.

RESULTS

Among 85 families, four families(4.70%) had seven SCA1 patients with the CAG repeat expanded to 53 to 62 repeats, five (5.88%) had twelve SCA2 patients with the CAG repeat expanded to 43 to 47 repeats, and 41 (48.23%) had 83 SCA3/MJD patients with the CAG repeat expanded to 68 to 83 repeats. Analysis of the mutation in these families showed a strong negative correlation between the size of the expanded CAG repeat and the age of disease onset. None of the SCA patients were positive for SCA6, SCA7, or DRPLA. Nor was any of the sporadic SCA patients positive for the CAG repeat expansion in the SCA1, SCA2, SCA3/MJD, SCA6, SCA7, or DRPLA gene.

CONCLUSION

The frequency of SCA3/MJD is substantially higher than that of SCA1 and SCA2 in the autosomal dominant SCA from Chinese families. Chinese SCA3/MJD patients are non-Portuguese. Clinical expressions of the various SCAs overlap one another and hence can make the phenotype-based diagnostic classification inaccurate in many instances. It is important for SCA clinical studies to make an SCA gene diagnosis and genotype analysis.

Elevated levels of soluble TNF receptors in bronchoalveolar lavage fluid in extrinsic allergic alveolitis

BACKGROUND

Soluble TNF receptors (sTNFR1 and sTNFR2) are inhibitors of TNF and can block TNF bioactivity. TNF plays an important role in the development of extrinsic allergic alveolitis (EAA).

OBJECTIVE

To evaluate whether sTNFR1 and sTNFR2 are locally increased in EAA.

METHODS

We measured sTNFR1 and sTNFR2 in bronchoalveolar lavage fluid (BALF) and serum from nine EAA patients and 11 control subjects using an ELISA method.

RESULTS

BALF sTNFR1 and sTNFR2 levels were 0.24+/- 0.04 ng/mL and 0.59+/-0.16 ng/mL in EAA patients, and thus significantly elevated in comparison with the controls (0.13+/-0.02 ng/mL and 0.08+/-0.04 ng/mL, both P<0.05). Serum sTNFR levels were not significantly different between the two groups. Both sTNFR1 and sTNFR2 concentrations in BALF correlated significantly with the lymphocyte percentage of BALF (r = 0.57 and 0.81, respectively).

CONCLUSION

The two alveolar sTNFRs, particularly sTNFR2, may be involved in the pathogenesis of EAA as counter-regulators of TNF.

Grb10, a positive, stimulatory signaling adapter in platelet-derived growth factor BB-, insulin-like growth factor I-, and insulin-mediated mitogenesis

Grb10 has been described as a cellular partner of several receptor tyrosine kinases, including the insulin receptor (IR) and the insulin-like growth factor I (IGF-I) receptor (IGF-IR). Its cellular role is still unclear and a positive as well as an inhibitory role in mitogenesis depending on the cell context has been implicated. We have tested other mitogenic receptor tyrosine kinases as putative Grb10 partners and have identified the activated forms of platelet-derived growth factor (PDGF) receptor beta (PDGFRbeta), hepatocyte growth factor receptor (Met), and fibroblast growth factor receptor as candidates. We have mapped Y771 as a PDFGRbeta site that is involved in the association with Grb10 via its SH2 domain. We have further investigated the putative role of Grb10 in mitogenesis with four independent experimental strategies and found that all consistently suggested a role as a positive, stimulatory signaling adaptor in normal fibroblasts. (i) Complete Grb10 expression from cDNA with an ecdysone-regulated transient expression system stimulated PDGF-BB-, IGF-I, and insulin- but not epidermal growth factor (EGF)-induced DNA synthesis in an ecdysone dose-responsive fashion. (ii) Microinjection of the (dominant-negative) Grb10 SH2 domain interfered with PDGF-BB- and insulin-induced DNA synthesis. (iii) Alternative experiments were based on cell-permeable fusion peptides with the Drosophila antennapedia homeodomain which effectively traverse the plasma membrane of cultured cells. A cell-permeable Grb10 SH2 domain similarly interfered with PDGF-BB-, IGF-I-, and insulin-induced DNA synthesis. In contrast, a cell-permeable Grb10 Pro-rich putative SH3 domain binding region interfered with IGF-I- and insulin- but not with PDGF-BB- or EGF-induced DNA synthesis. (iv) Transient overexpression of complete Grb10 increased whereas cell-permeable Grb10 SH2 domain fusion peptides substantially decreased the cell proliferation rate (as measured by cell numbers) in normal fibroblasts. These experimental strategies independently suggest that Grb10 functions as a positive, stimulatory, mitogenic signaling adapter in PDGF-BB, IGF-I, and insulin action. This function appears to involve the Grb10 SH2 domain, a novel sequence termed BPS, and the Pro-rich putative SH3 domain binding region in IGF-I- and insulin-mediated mitogenesis. In contrast, PDGF-BB-mediated mitogenesis appears to depend on the SH2 but not on the Pro-rich region and may involve other, unidentified Grb10 domains. Distinct protein domains may help to define specific Grb10 functions in different signaling pathways.

Increased expression of apoptosis signalling receptors by alveolar macrophages in sarcoidosis

The Fas receptor (FasR) and the tumour necrosis factor (TNF) receptor 55/60 kDa (TNFR1) are recognized as apoptosis signalling receptors. They are known to be expressed by lymphocytes in association with immune regulation and immunological disorders. This study aimed to investigate the expression of FasR and TNFR1 by alveolar macrophages (AM) in patients with sarcoidosis. Bronchoalveolar lavage (BAL) was performed in 12 patients with active sarcoidosis and 11 control subjects. BAL cells were characterized by monoclonal antibodies using a peroxidase-antiperoxidase method. Both FasR and TNFR1 were expressed on a higher percentage of AM in sarcoidosis with respect to control subjects (mean +/-sem 40.8+/-3.1% versus 14.9+/-1.7%, p<0.001 and 61.9+/-3.3% versus 23.1+/-4.1%, p<0.001, respectively). There was a close relationship between the expression of FasR and TNFR1 on AM (r = 0.86, p<0.001). The percentages of FasR+ AM and TNFR1+ AM were in direct proportion to the percentage of BAL lymphocytes (r = 0.75 and 0.84), the CD4/CD8 ratio (r = 0.78 and 0.78), and the percentage of the CD14+ AM subset (r = 0.77 and 0.87), p<0.001 for all correlations. This study indicates that alveolar macrophages expressing apoptotic receptors are increased in patients with active sarcoidosis. Further studies are required to determine whether these alveolar macrophages from patients with sarcoidosis undergo apoptosis more readily than those from control subjects.

[Pharmacological comparison between volatile oil and water extract]

OBJECTIVE

To compare the pharmacological differences between volatile oil and water extract in eight aromatic drugs for resolving dampness.

METHOD

Volatile oil and water extract of eight commonly used aromatic drugs for resolving dampness were ig administered to rats respectively, and the effects of volatile oil and water extract on the secretion of gastric juice, volume of gastric mucous blood flow and activity of SOD in gastric mucous membrane were studied.

RESULT

It was shown that the effects of aromatic volatile oil in eight drugs on the indexes mentioned above were generally equal or similar to those of water extract, and it was obvious that the volatile oil in some high oil content drugs such as Amonum cardamomum L(Baidoukou), Alpinia katsumadai Hagata (Caodoukou), Amomum villosum Lour (Saren), and Amomum tsao-ko Crevost et Lem (Caogou) had better effects on the secretion of gastric juice and volume of gastric mucous blood flow that those of water extract.

CONCLUSION

It has been pharmacologically proved that in using aromatic drugs for resolving dampness, the loss of aromatic (volatile) components should be avoided.

Requirements for urology and renal dialysis PC-based telemedicine applications: comparative analysis

The Imaging Science and Information Systems (ISIS) Center of the Department of Radiology at Georgetown University Medical Center (GUMC) has been developing technical requirements for different telemedicine applications. This paper details the process through which those technical requirements are determined and shows how they may differ substantially, depending on the clinical need. This information is presented in light of two telemedicine applications being undertaken at GUMC: a urology application for the management of patients with surgical stone disease and a nephrology application for monitoring of renal dialysis patients.

Vertical shift in cerebral autoregulation curve: a graded head-up tilt study

According to the classical theory of cerebral autoregulation, cerebral blood flow (CBF) will be maintained at a near-constant level for cerebral perfusion pressure (CPP) within the range of 60-150 mmHg. In recent years, however, studies with contradicting results have demonstrated a change in CBF when the level of CPP had not changed significantly. It is suggested that a shift in the autoregulation curve may have taken place along the horizontal axis or along the vertical axis. This paper describes previously unreported findings of a graded head-up tilt (HUT) study which was designed as a preliminary experiment to test the protocol for possible use on astronauts upon returning from space-flight. Data from this study tend to support the findings of previous studies regarding possible shifts in the cerebral autoregulation curve. Five female and four male healthy volunteers were exposed to HUT for 5 minutes at each angle of 30 degrees, 60 degrees, and 90 degrees. Throughout the test, cerebrovascular and cardiovascular responses were evaluated by use of continuous acquisition of mean flow velocity (MFV) from the right middle cerebral artery with transcranial Doppler sonograhy, mean arterial blood pressure (MABP, Finapres) and heart rate (HR, ECG). Based on the last 60 seconds of data at each tilt angle and baseline, the percentage changes in MFV from baseline were found to be similar to those in MABP at the level of the brain (MABPbrain), and both were significant (p<0.05) at the 60 degrees (-9.1 +/- 7% for MABP brain, -9.8 +/- 5% for MFV) and 90 degrees (-13 degrees +/- 8%, -12.0 +/- 6%) positions. Heart rate (HR) increased significantly (p<0.05) from the baseline at 30 degrees (6.3 +/- 5%) through 90 degrees (23.3 +/- 8%). The trend toward decreasing MFV in normal subjects, even while MABP brain remained within the normal limits of cerebral autoregulation, may suggest a downward shift of the cerebral blood flow plateau in the classic cerebral autoregulation curve.

[The tissue oxygenation status and the effects of mechanical ventilation on oxygen dynamics in COPD patients with hypercapnia]

OBJECTIVE

To assess the tissue oxygenation status and the effects of mechanical ventilation (MV) on oxygen dynamics in COPD patient with hypercapnia.

METHODS

Gastric intramucosal pH (pHi) measured by gastric tonometer was examined in 19 patients before and after MV.

RESULTS

pHi calculated before MV was 7.18 +/- 0.06; After receiving MV, pHi increased gradually until above 7.32 in 4 days; during weaning, there were no significant changes in pHi before and after discontinuation. The correlation analysis showed that there was no correlation between pHi and pHa (r = 0.352, P > 0.05), PgCO(2) and PaCO(2) (r = 0.421, P > 0.05), suggesting that pHi measurement would not be affected by hypercapnia.

CONCLUSIONS

Our study showed that tissue oxygenation insufficiency existed in COPD exacerbation stage. Gastric pHi may be used as the parameter to estimate tissue oxygenation status and a predictor of weaning from mechanical ventilation.

Self-oriented regular arrays of carbon nanotubes and their field emission properties

The synthesis of massive arrays of monodispersed carbon nanotubes that are self-oriented on patterned porous silicon and plain silicon substrates is reported. The approach involves chemical vapor deposition, catalytic particle size control by substrate design, nanotube positioning by patterning, and nanotube self-assembly for orientation. The mechanisms of nanotube growth and self-orientation are elucidated. The well-ordered nanotubes can be used as electron field emission arrays. Scaling up of the synthesis process should be entirely compatible with the existing semiconductor processes, and should allow the development of nanotube devices integrated into silicon technology.

The Mycobacterium tuberculosis small heat shock protein Hsp16.3 exposes hydrophobic surfaces at mild conditions: conformational flexibility and molecular chaperone activity

Hsp16.3, the alpha-crystallin-related small heat shock protein of Mycobacterium tuberculosis that is maximally expressed during the stationary phase and is a major membrane protein, has been reported to form specific trimer-of-trimers structure and to act as an effective molecular chaperone (Chang Z et al., 1996, J. Biol Chem 271:7218-7223). However, little is known about its action mechanism. In this study, Hsp16.3 conformational intermediates with dramatically increased chaperone activities were detected after treatment with very low concentrations of guanidine hydrochloride (0.05 M), urea (0.3 M), or mild heating (30 degrees C). The intermediates showed a significant increase in their capacity to bind the hydrophobic probe 1-anilino-8-naphthalene sulfonate (ANS), indicating an increased exposure of hydrophobic surfaces. Interestingly, the greatest chaperone activities of Hsp16.3 were observed in the presence of 0.3 M guanidine HCl or when heated to 35 degrees C. CD spectroscopy studies revealed no significant changes in protein secondary and tertiary structures at these mild treatments. Our in vitro studies also indicate that long-time-heated Hsp16.3, heated even to temperatures as high as 85 degrees C, has almost the same, if not a slightly greater, chaperone activities as the native protein when cooled to room temperature and its secondary structures also almost recovered. Together, these results suggest that Hsp16.3 modulates its chaperone activity by exposing hydrophobic surfaces and that the protein structure is highly stable and flexible, thus highly adapted for its function.

Diet and exercise in the treatment of obesity: effects of 3 interventions on insulin resistance

BACKGROUND

In short-term studies, diet and exercise both improve insulin sensitivity.

OBJECTIVE

To determine the effects of a 48-week supervised diet and exercise program on weight and insulin sensitivity after initial weight loss and weight maintenance, and then subsequent weight regain over 96 weeks.

METHODS

Forty-five obese women were randomly assigned to 1 of 3 treatment groups: (1) diet alone, (2) diet and aerobic training, and (3) diet and strength training. All subjects received the same 48-week group behavior modification program and diet (approximately 3879 kJ/d [approximately 925 kcal/d] for the first 16 weeks; approximately 6276 kJ/d [approximately 1500 kca/d] thereafter). Exercising subjects were provided 3 supervised exercise sessions per week for the first 28 weeks and 2 sessions weekly until week 48. During weeks 48 to 96, subjects were unsupervised. Oral glucose tolerance tests were performed at baseline and weeks 16, 24, 44, and 96.

RESULTS

Subjects across the 3 conditions achieved a mean weight loss of 13.8 kg by week 16, which was associated with decreased insulin levels (61.8% of baseline) There were no significant differences among groups in changes in body mass index, which is a measure of weight in kilograms divided by the square of the height in meters, weight, glucose tolerance, or insulin levels at weeks 16, 24, and 44. No additional beneficial effect of aerobic or strength exercise on insulin resistance, as reflected by serum insulin levels before and after a glucose load, was demonstrated. The 22 subjects who were studied at week 96 maintained a loss of approximately 10% of initial weight. Insulin levels, however, had returned to pretreatment levels.

CONCLUSIONS

This study confirms the beneficial effect of weight reduction on hyperinsulinemia in obese individuals. Participation in supervised exercise did not result in additional improvement in weight loss or insulin sensitivity. We also observed a marked increase in insulin levels with only partial weight regain. Determining the amount of sustained weight loss necessary for continued improvement in insulin sensitivity will require further study.

Drug target validation and identification of secondary drug target effects using DNA microarrays

We describe here a method for drug target validation and identification of secondary drug target effects based on genome-wide gene expression patterns. The method is demonstrated by several experiments, including treatment of yeast mutant strains defective in calcineurin, immunophilins or other genes with the immunosuppressants cyclosporin A or FK506. Presence or absence of the characteristic drug 'signature' pattern of altered gene expression in drug-treated cells with a mutation in the gene encoding a putative target established whether that target was required to generate the drug signature. Drug dependent effects were seen in 'targetless' cells, showing that FK506 affects additional pathways independent of calcineurin and the immunophilins. The described method permits the direct confirmation of drug targets and recognition of drug-dependent changes in gene expression that are modulated through pathways distinct from the drug's intended target. Such a method may prove useful in improving the efficiency of drug development programs.

Detection of sinusoidal amplitude modulation at unexpected rates

The detectability of sinusoidal amplitude modulation at unexpected modulation rates was assessed using a probe-signal method. With this method, three listeners were led to expect a target modulation rate (4, 32, or 256 Hz) by presenting the signal most often at that rate, and sensitivity to modulation at six other unexpected rates between 4 and 256 Hz was measured via occasionally presented probe modulation rates. The modulation phase was random on each two-interval forced-choice trial and the overall level of the 500-ms broadband carrier was randomly varied between 55 and 75 dB SPL across intervals. The modulation depth at each rate was set so that the modulation was detected on about 90% of the trials when only that rate was presented. Performance at the unexpected rates depended upon the target rate. For the 4-Hz target, modulation at all rates was detected on about 80% of the trials. For the 32- and 256-Hz targets, unexpected modulation rates of 16 Hz and above were detected on 80%-90% of the trials, but modulation rates below 16 Hz were detected nearly at chance. The influence of expectation of modulation rate on the detection of sinusoidal amplitude modulation is not readily predicted by current models of modulation detection.

[The effects of diltiazem on pulmonary hemodynamics and oxygenation in copd induced pulmonary hypertension]

OBJECTIVE

To study hemodynamic the effects of intravenous diltiazem on COPD induced pulmonary hypertention.

METHODS

11 cases in exacerbation stage were chosen to study. Swan-Ganz catheterization were taken for hemodynamic monitoring.

RESULTS

After the administration of diltiazem, pulmonary vascular resistance, pulmonary pressure, right artrial pressure and heart rate decreased significantly (the extents decreased were 14.0 kPa.s-1.L-1, 0.62-1.27 kPa, 0.27-0.40 kPa and 25-30 beats/min respectively, P < 0.05); Cardiac output and stroke volume increased identically (the extents increased were 0.3-0.6 L.min-1.m-2 and 5-9 ml.beat-1.m-2 respectively, P < 0.05); No significant changes found in Qs/Qt, PaO2 and systemic blood pressure.

CONCLUSION

Our study showed that diltiazem produces beneficial pulmonary hemodynamic effects without oxygenation compromise in COPD cases and has a strong indication in those who complicated with superventricular tachycardia.

Deployable teleradiology and telemedicine for the US military

The US military has been an effective proponent of digital imaging and teleradiology for the past 15 years. A digital imaging network that can eliminate the use of X-ray film can make the requirements simpler for military medicine. X-ray film requires the storage of new, unexposed films that have a fixed shelf life, and the storage and use of chemicals and water for processing. In some deployed situations, the chemical discharge has to be collected and shipped out of the deployed area. The technology of electronic imaging is therefore intrinsically important to military medicine. In December of 1995, the US government started to deploy 20000 US troops to Bosnia-Herzegovina as part of NATO's peace keeping operation (IFOR). A full complement of medical support facilities was to be established in the Bosnia region and Hungary where the deployment was staged. Primetime III was a project to deploy telemedicine and teleradiology capabilities linking these medical treatment facilities (MTF). The deployment of telemedicine was not the responsibility of our engineering team. This paper deals with the deployable teleradiology (DEPRAD) system that was installed by the ISIS Center at a number of facilities for filmless radiology and teleradiology services.

AIDS risk perception among women drug users in Hartford, CT

This paper reports the findings of a study of congruence between AIDS risk perception and risk behavior in a sample of outreach-recruited out-of-treatment injection and non-injection crack cocaine using women in Hartford, CT. While rates of drug- and sex-related AIDS risk were high in this sample, perception of risk was low among many of the respondents. Variation in risk perception reflects sociodemographic differences in the sample, with those women who were most socially isolated exhibiting the greatest incongruence between personal risk and risk perception. Women who have had contact with health or social service programs were the most likely to report reductions in risk behavior.

Effects of dizocilpine (MK-801) on motor activity and memory

The effects of MK-801 upon motor activity and memory were assessed in a novel use of open-field behavior testing. In this study, rats were treated with different doses of MK-801 (0.025, 0.05, 0.1 and 0.2 mg/kg) and given a brief 10-min exposure to an open-field in which locomotor activity and within-session habituation were measured. Doses of MK-801 < or =0.1 mg/kg had no effect upon locomotor activity or within-session habituation. MK-801 0.2 mg/kg produced a marked hyperlocomotion and completely prevented within-session habituation. One day later, the animals were tested for their retention of habituation to evaluate the effects of MK-801 on memory processes. In that animals treated with 0.2 mg/kg MK-801 failed to habituate to the novel environment under the influence of 0.2 mg/kg MK-801, it was not surprising that these animals were impaired on the retention test for the novel environment. Importantly, however, the 0.1 mg/kg MK-801 treatment, which did not affect locomotor activity or within-session habitation to the novel environment, severely interfered with retention of the novel environment. Additional experiments indicated that this result could not be accounted for by drug conditioning or drug state-dependent effects. Thus, the results indicated that MK-801 can produce profound effects upon motor activity and memory and that these two effects can be disassociated.

Growth regulation of ovarian cancer cell line HO-8910 by transforming growth factor beta 1 in vitro

OBJECTIVE

To further understand the role of growth regulation of human ovarian cancer cells by transforming growth factor (TGF) beta 1.

METHODS

The cell proliferation, cAMP synthesis, gene expression, and induction of programmed cell death (PCD) in human epithelial ovarian cancer cell line HO-8910 cells exposed to TGF beta 1 in vitro were studied.

RESULTS

TGF beta 1 inhibited cell growth and DNA synthesis, and induced G0/G1 arrest in cell cycle. It could also trigger PCD in cells. This induction of PCD may occur within G0/G1 phase. Meanwhile, the assay also showed that TGF beta 1 could inhibit the mRNA expression of c-myc, EGFR and TGF beta 1 genes in cells.

CONCLUSIONS

TGF beta 1 can not only act as an autocrine to inhibit cell proliferation, but also trigger PCD in HO-8910 cells. These functions may be fulfilled through some specific signal transduction pathways.

Fullerene pipes

Single-wall fullerene nanotubes were converted from nearly endless, highly tangled ropes into short, open-ended pipes that behave as individual macromolecules. Raw nanotube material was purified in large batches, and the ropes were cut into 100- to 300-nanometer lengths. The resulting pieces formed a stable colloidal suspension in water with the help of surfactants. These suspensions permit a variety of manipulations, such as sorting by length, derivatization, and tethering to gold surfaces.

[Living related liver transplantation: a case report]

OBJECTIVE

To study a case of living related liver transplantation.

METHOD

The patient was a 10-year-old girl who suffered from congenital diffuse intrahepatic cholangiectasis, recurrent cholangitis and hepatocirrhosis. The donor was the patient's father aged 40. The left lateral lobe of donor's liver was cut and grafted to the patient. Intensive care and treatment as well as follow-up were given after operation.

RESULT

For the donor, the operation lasted 400 min, with 410 ml bleeding and 300 g liver removed. The recovery was satisfactory. For the recipient, the operation lasted 652 min, with 1665 ml bleeding, 80 min non-liver stage, 0 min graft hot ischemic stage, and 137 min cold ischemic stage. Immunosuppressive therapy was given using cyclosporin A, azathioprine and adrenocortical hormones. There was an acute rejection 11 days after operation, which was controlled using hormone impulsive therapy. The patient has been surviving 7 months with normal liver function.

CONCLUSION

The living related liver transplantation is feasible under modern surgical conditions. It is demonstrated that perfect postoperative management is the key for the successful liver transplantation.

Tensile strength of lens capsules in eye-bank eyes

PURPOSE

To measure the tensile strength of the anterior and posterior lens capsules in eye-bank eyes and study the tensile strength of capsules dehydrated with hypertonic glucose solution.

SETTING

Tongren Hospital, Beijing, China.

METHODS

The in situ anterior and posterior capsules of 35 eye-bank eyes (Group 1) donated by healthy men aged 20 to 40 years (mean 27.1 years) were measured with a biomembrane strength device. Sixteen eyes (Group 2), from donors aged 20 to 37 years (mean 27.0 years) and similar to those in Group 1, were measured in the same way after the anterior and posterior capsules were exposed to glucose 50% solution for 15 minutes.

RESULTS

In Group 1, anterior and posterior capsule strength was 6.269 +/- 1.118 and 3.755 +/- 0.835 g, respectively (P < .01), and the correlation between the tensile strength of the anterior and posterior capsules was statistically significant (r = .94; P < .001). In Group 2, the strength of the capsules increased to 9.024 +/- 0.586 and 4.424 +/- 0.761 g, respectively, a finding that was statistically significantly different from that in Group 1 (P < .01 and .05, respectively.

CONCLUSION

The tensile strength of the anterior capsule was stronger than that of the posterior capsule under the experimental conditions. Glucose 50% solution has the potential to increase the tensile strength of anterior and posterior capsules.

Population heterogeneity of higher-plant mitochondria in structure and function

Mitochondria of rapidly developing mungbean seedlings were fractionated into four populations: two density classes, each from a 1500S and a 150S pellet. Each of the four populations exhibited cytochrome c oxidase (COX) activity and contained mitochondrial DNA and cardiolipin; plastid and glyoxysome content were found to be relatively low. Five mitochondrial membrane proteins, COXII/III, ATPase alpha/beta and porin, and a matrix enzyme, manganese superoxide dismutase (MnSOD), were detected by immunoblots in all four populations. Another matrix enzyme, pyruvate dehydrogenase was detected only in the two respiratory-competent 1500S populations. The two 150S populations contained a previously unidentified organelle that lacked demonstrable respiratory capability. This organelle, which we have tentatively referred to as "slow-sedimenting (ss-) mitochondrion", was small in size (below light-optics resolution, 70-300nm, majority < or =200nm) and possessed a peculiar looking boundary membrane, ribosomes, and an occasional prominent electron-dense spot. Characteristically, ss-mitochondria were almost always in contact with a filament-aligned membrane-like structure of varying length. Cristae structure, while undetected in small ss-mitochondria, appeared in larger individuals. Typical mitochondria were found in the denser 1500S population, while the lighter 1500S population consisted of 300-800 nm mitochondria exhibiting a varying degree of size-dependent inner membrane folding. Using electron microscopy (EM) immunolocalization and serial sectioning, we have identified in situ organelles resembling in size and in fine structure the ss-mitochondria, which also exhibit a size-dependent folding of the inner membrane. These results suggest that small ss-mitochondria may undergo a progressive development in situ. Taken together, our findings demonstrate the existence of a pattern of structure-function-coordinated gross heterogeneity among mitochondria. This pattern of mitochondrial heterogeneity, characterized both in isolated mitochondria and in situ, implies that small ss-mitochondria may represent a type of "nascent mitochondria" derived from a yet unidentified mitochondria-propagation mode operating during rapid seedling growth. Mitochondrial division by binary fission, characterized by the appearance of dumbbell-shaped intermediates, was also detected.

Design and baseline characteristics of the Veterans Affairs Non-Q-Wave Infarction Strategies In-Hospital (VANQWISH) trial. VANQWISH Trial Research Investigators

OBJECTIVES

The Veterans Affairs Non-Q-Wave Infarction Strategies In-Hospital (VANQWISH) trial was designed to compare outcomes of patients with a non-Q wave myocardial infarction (NQMI) who were randomized prospectively to an early "invasive" strategy versus an early "conservative" strategy. The primary objective was to compare early and late outcomes between the two strategies using a combined trial end point (all-cause mortality or nonfatal infarction) during at least 1 year of follow-up.

BACKGROUND

Because of the widely held view that survivors of NQMI are at high risk for subsequent cardiac events, management of these patients has become more aggressive during the last decade. There is a paucity of data from controlled trials to support such an approach, however.

METHODS

Appropriate patients with a new NQMI were randomized to an early "invasive" strategy (routine coronary angiography followed by myocardial revascularization, if feasible) versus an early "conservative" strategy (noninvasive, predischarge stress testing with planar thallium scintigraphy and radionuclide ventriculography), where the use of coronary angiography and myocardial revascularization was guided by the development of ischemia (clinical course or results of noninvasive tests, or both).

RESULTS

A total of 920 patients were randomized (mean follow-up 23 months, range 12 to 44). The mean patient age was 61 +/- 10 years; 97% were male; 38% had ST segment depression at study entry; 30% had an anterior NQMI; 54% were hypertensive; 26% had diabetes requiring insulin; 43% were current smokers; 43% had a previous acute myocardial infarction; and 45% had antecedent angina within 3 weeks of the index NQMI.

CONCLUSIONS

Baseline characteristics were compatible with a moderate to high risk group of patients with an NQMI.

A telemedicine consultative service for the evaluation of patients with urolithiasis

OBJECTIVES

A 6-month pilot teleconsultative project linking Georgetown University Medical Center (GUMC) in Washington, DC, and City Hospital in Martinsburg, West Virginia, 90 miles away, was designed to assess the effectiveness of telemedicine on the clinical decision-making process for patients with urolithiasis.

METHODS

The telemedicine system designed and tested for this project was based on a PC-based platform. Videoconferencing and review of the patient's imaging studies were performed over an Integrated Service Digital Network (ISDN) with 3 Basic Rate (BRI) ISDN lines providing a 336-kilobytes/s bandwidth through an Inverse Multiplexor (IMUX). Treatment options were recorded for the clinical trial group and a simulated study group by the consulting urologist after the initial telephone consultation, after the telemedicine consultation, and after examination of those patients transferred to GUMC.

RESULTS

A total of 32 telemedicine consultations were performed: 14 in the clinical trial group and 18 in the simulated study group. The recommendation of the consulting urologist at the tertiary center was altered in 12 patients (37.5%) after the telemedicine consultation compared with the recommended treatment after the initial telephone consultation.

CONCLUSIONS

In the evaluation of patients with urolithiasis, this telemedicine application enhanced the clinical decision-making process by allowing for improved quality of care through immediate access and effective transfer of information between the referring urologist, the patient, and the stone center specialist.

[The changes of lipid metabolism and hemorrheology in intrahepatic cholestasis during pregnancy]

OBJECTIVE

To identify the influence of the increased level of serum cholyglycine (CG) on lipid metabolism and hemorrheology in patients with intrahepatic cholestasis during pregnancy (ICP).

METHODS

The concentrations of serum CG, total cholesterol (CH), triglycerides (TG), high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), high shear and low shear of blood specific viscosity (HS and LS), plasma specific viscosity (PV) and hematocrit (HCT) were measured in 68 cases of primiparas with single pregnancy and 30 healthy nonpregnant women respectively. The group of ICP was composed of 35 cases with CG > 6 mumol/L, the group of normal pregnancy, 33 cases with CG < 6 mumol/L.

RESULTS

The means of CG and the lipidic parameters in the two pregnant groups were significantly higher than those in the non-pregnancy group (P < 0.02-0.001) except the means of HDL-C between the groups of ICP and non-pregnancy. The levels of LDL-C, LDL-C/HDL-C, LS, PV and HCT in the ICP were significantly higher than those in the normal pregnancy group (P < 0.02-0.001).

CONCLUSIONS

There are significant changes of lipid metabolism and hemorrheology in patients with ICP. However, these changes could be corrected after pregnancy termination, when the level of serum CG returned to normal. The results suggest that the pathophysiologic changes of ICP are associated with increased level of serum CG.

UAS(MAG1), a yeast cis-acting element that regulates the expression of MAG1, is located within the protein coding region of DDI1

MAG1 and DDI1 are two divergently transcribed DNA damage-inducible genes from Saccharomyces cerevisiae. Previous studies have shown that MAG1 induction requires an upstream activating site (UAS) located between nucleotides -376 and -330. Here we show that a 24-bp oligonucleotide from within the UAS(MAG1) region forms a sequence-specific DNA-protein complex with partially purified proteins from S. cerevisiae. Point mutations introduced into the 24-bp oligonucleotide inhibited the formation of the DNA-protein complex and decreased the level of induction of MAG1-lacZ. By determining the transcription and translation start points of both MAG1 and DDI1, an interesting, indeed unprecedented feature of genome organization in eukaryotes was revealed: UAS(MAG1) actually lies within the protein-coding region of DDI1. Although tightly linked to each other, and co-induced upon treatment with DNA-damaging agents, DDI1 does not share the UAS(MAG1) required for DNA damage induction of MAG1. Furthermore, MAG1 and DDI1 respond differently in the presence of the protein synthesis inhibitor cycloheximide, suggesting that these two genes are regulated by different mechanisms in the absence of de novo protein synthesis.

The study of IL-1 beta, TNF-alpha, IL-6 gene expression and plasma levels on hemodialysis before and after dialyzer reuse

OBJECTIVE

To investigate the biocompatibility of dialyzer reuse.

METHODS

Twenty-two hemodialysis patients were randomized into cuprophan (CU, 7), polymethylmethacrylate (PMMA, 7) and polysulphone (PS, 8) membrane groups to observe IL-1 beta, TNF-alpha, IL-6 gene expression and their plasma levels by using themselves as control with enzyme-linked immunosorbent assay (ELISA), reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization.

RESULTS

Plasma levels of interlukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) were 14.07 +/- 3.32 pg/ml, 67.41 +/- 19.79 pg/ml, 83.67 +/- 40.34 pg/ml; 12.80 +/- 3.01 pg/ml, 49.65 +/- 9.75 pg/ml, 33.36 +/- 12.14 pg/ml and 14.41 +/- 3.16 pg/ml, 80.56 +/- 23.22 pg/ml, 48.14 +/- 16.01 pg/ml, respectively, after patients dialyzed with CU, PMMA and PS membranes. Plasma cytokine levels decreased after reuse compared with those before reuse in each group. But no significant difference was found between them (P > 0.05); the levels of IL-1 beta, TNF-alpha, IL-6 gene expression after reuse were 5.61 +/- 0.33, 2.11 +/- 0.12, 5.04 +/- 0.19%; 2.43 +/- 0.19, 1.29 +/- 0.11, 3.48 +/- 0.20% and 2.48 +/- 0.20, 1.24 +/- 0.11, 3.22 +/- 0.20% respectively by in situ hybridization, and 0.92 +/- 0.07, 0.63 +/- 0.05, 0.53 +/- 0.05; 0.61 +/- 0.06, 0.47 +/- 0.04, 0.37 +/- 0.03 and 0.59 +/- 0.05, 0.44 +/- 0.04, 0.38 +/- 0.03 by RT-PCR, respectively. After reuse there was significant decrease as compared with that before reuse (P < 0.001, P < 0.005 and P < 0.05, respectively).

CONCLUSIONS

This suggested reprocessing dialyzer with formaldehyde reduced cytokine release and gene expression in peripheral blood mononuclear cells and enhanced dialyzer biocompatibility. It would be beneficial to reduce the dialysis cost and may reduce the complication related to a long term hemodialysis.

[Induction of apoptosis in human ovarian cancer cell line HO-8910 by transforming growth factor beta 1]

OBJECTIVE

To investigate the mechanism of inhibitory effects of Transforming Growth Factor beta 1 (TGF-beta 1) on human ovarian cancer cell in vitro.

METHODS

The possibility of induction of apoptosis in human ovarian cancer cell line HO-8910 cells after treatment with TGF-beta 1 was studied by using methods of DNA electrophoresis, P1-staining, TdT-mediated dUTP-x nick end labeling and flow cytometer assay (FCM); and the kinetic change of expression of c-myc was also studied by relative quantified RT-PCR.

RESULTS

DNA-strand nicks were present in cells after treatment with TGF-beta 1 at the final concentration of 20 ng/ml for 36 hours. The percent of labeled cells reached 75.55% on the time of 48 hours, PI staining-FCM assay also showed subdiploid peak of apoptotic cells at the same time. The typical apoptotic DNA ladder was present in genomic DNA preparation after treatment with TGF-beta 1 for 60 hours, meanwhile, the expression of c-myc in cells started to decrease beginning at treatment for 9 hours.

CONCLUSIONS

TGF-beta 1 can induce apoptosis in HO-8910; such an inductive effect may occur mainly in G0/G1 phase. The effects of TGF-beta 1 on the inhibited expression of c-myc and on the enhancement of cAMP concentration may also play important roles in the process of apoptotic induction.

[Changes of plasma endothelium-derived relaxing factor and endothelin-1 in patients with chronic cor pulmonale at exercise test]

OBJECTIVE

The authers investigated the levels of plasma EDRF-nitric oxide (NO) and ET-1 in 10 cases of cor pulmonale at exercise.

METHODS

Using the technologies of cardiac catheter, radioimmunization and biochemical analysis.

RESULTS

The level of plasma NO was lower in group A (mean pulmonary artery pressure (mPAP) < 2.67 kPa) than in group B (mPAP > or = 2.67 kPa) at rest; the content of plasma NO increased more markedly in group A than in group B during exercise; there was no change in the content of ET-1 in both groups; mPAP strongly correlated with plasma NO or ET-1 in both groups.

CONCLUSIONS

The patients with cor pulmonale at early stage may be in a state of compensated release of NO, but its release reserve has been reduced.

Restoration of nitric oxide production by aldose reductase inhibitor in human endothelial cells cultured in high-glucose medium

The effects of elevated glucose and aldose reductase inhibitor (ARI:ONO-2235) on nitric oxide (NO) production in cultured human umbilical endothelial cells (HUVEC) were evaluated. Aldose reductase and nitric oxide synthase(NOS) share NADPH as an obligate cofactor, therefore it is suggested that the enhanced of glucose flux (27.5 mM) by aldose reductase inhibited NO production by blunting NOS activity. However, the addition of ONO-2235 (100 microM) prevented the inhibition of [NO2-] production. Since ARI decreases glucose-mediated inhibition of NO production in HUVEC. this agent might ameliorate endothelial function associated with diabetes.

Phase independence of pitch produced by narrow-band sounds

Three listeners matched the pitch of a simple tone to that of narrow-band complex signals having different phases. The pitch matches were independent of the phases; the frequency of the simple tone approximately equaled the center of gravity of the power spectrum of each complex signal. This result is inconsistent with a model that calculates the pitch of a waveform as the average of instantaneous frequency weighted by the envelope of the waveform.

[The effects of growth factors on gene expressions in human ovarian cancer cell line HO-8910]

The effects of EGF and TGF beta 1 on onco gene expressions was studied by RT-PCR technique in an ovarian cancer cell line HO-8910. The results showed that TGF beta 1 could inhibit mRNA expression of TGF beta 1 gene and that of c-myc, EGFR and c-erbB2 genes in HO-8910 cells in vitro. However, EGF could enhance the mRNA expressions of c-myc, c-erbB2 and EGFR to various extents, but inhibit that of TGF beta 1 gene.

Crystalline Ropes of Metallic Carbon Nanotubes

Fullerene single-wall nanotubes (SWNTs) were produced in yields of more than 70 percent by condensation of a laser-vaporized carbon-nickel-cobalt mixture at 1200degreesC. X-ray diffraction and electron microscopy showed that these SWNTs are nearly uniform in diameter and that they self-organize into "ropes," which consist of 100 to 500 SWNTs in a two-dimensional triangular lattice with a lattice constant of 17 angstroms. The x-ray form factor is consistent with that of uniformly charged cylinders 13.8 +/- 0.2 angstroms in diameter. The ropes were metallic, with a single-rope resistivity of <10(-4) ohm-centimeters at 300 kelvin. The uniformity of SWNT diameter is attributed to the efficient annealing of an initial fullerene tubelet kept open by a few metal atoms; the optimum diameter is determined by competition between the strain energy of curvature of the graphene sheet and the dangling-bond energy of the open edge, where growth occurs. These factors strongly favor the metallic (10,10) tube with C5v symmetry and an open edge stabilized by triple bonds.

Characterization of polyion counterion interactions in cartilage by 23Na NMR relaxation

Nuclear quadrupole relaxation is a sensitive measure of electrolyte environments. We used the relaxation of 23Na to probe mobile ion-matrix interactions and the electrostatic structure of the polyelectrolyte extracellular matrix of cartilage. Specifically, we measured spin-lattice and spin-spin relaxation times of 23Na in bovine nasal cartilage at 132 MHz under several conditions. Matrix fixed charge density was reduced by protonating anionic sites and by matrix digestion with trypsin and the relaxation times compared to controls. Under all conditions studied, measured longitudinal relaxation was monoexponential with values ranging from 16-32 msec. Transverse relaxation exhibited biexponential behavior in all cartilage samples with a fast component in the range of 2 to 5 ms and a slow component between 16 and 53 ms. Reduction in matrix fixed charge density in all cases led to a decrease in the relaxation rates. The results suggest a two-site model for Na+ ions in cartilage and a relaxation mechanism involving both polyion segmental motion and counterion diffusion. In the context of ion condensation theory, the implication of a two-site model is that the mean polyion-polyion spacing may be less than 0.7 nm. The mean polyion-counterion spacings were estimated by calculating correlation times and quadrupole coupling constants. These spacings were found to be 0.5-0.7 nm.

Decision rules of listeners in spectral-shape discrimination with or without signal-frequency uncertainty

A correlation technique was used to assess the decision rules of three listeners in two cases of spectral-shape discrimination tasks. In one case the signal frequency was fixed, and in the other it was randomly varied within each block of trials. In order to estimate the decision rule of the listeners, the experimenter superimposed random level perturbations on each frequency component upon each stimulus presentation. Over many trials, correlation coefficients were computed between the random perturbations and the binary responses of the listeners, and were expressed as a function of signal level. For both the fixed- and random-signal cases, the measured correlation functions were in reasonably good agreement with those predicted based on the likelihood-ratio decision rules. Thus the listeners appeared to use information nearly optimally in discriminating spectral shapes. This investigation demonstrated that the correlation technique can be used to reveal the decision rules for cases where the decision statistics are nonlinear functions of the observations.

The optimum decision rules in the same-different paradigm

In this paper we derive the optimum (likelihood-ratio) decision statistic for a same-different paradigm. The likelihood ratio is dependent on the degree of correlation between the two observations on each trial. For the two extreme cases in which the observations are either independent or highly correlated, the optimum decision rule is identical to each of two previously suggested decision rules. For these two cases, the receiver-operating characteristic (ROC) curves are calculated. Finally, an experimental procedure is suggested for assessing the decision rule actually used by the observer in a same-different task.

Glutathione S-transferases in the Japanese quail: tissue distribution and purification of the liver isozymes

Cytosolic glutathione S-transferase (GST) activities toward 1-chloro-2,4-dinitro-benzene (CDNB), 1,2-dichloro-4-nitrobenzene (DCNB), ethacrynic acid (EA), 1,2-epoxy-3-(p-nitrophenoxyl)propane (EPNP), trans-4-phenyl-3-buten-2-one(t-PBO), delta 5-androstene-3,17-dione (ASD) and trans-stilbene oxide (t-SO); cytosolic glutathione peroxidase activity toward cumene hydroperoxide (CuOOH); and microsomal GST activity toward CDNB were examined in liver, kidney, brain, and lung of adult male and female Japanese quail. In all cases, the renal specific activity per milligram protein was higher than the hepatic activity and was the highest among the four tissues examined. No consistent sex differences in GST activity were observed. The GSTs were purified from quail liver cytosol by S-hexylglutathione and glutathione affinity chromatography. Total GSTs eluted from the S-hexylglutathione affinity column were further separated by chromatofocusing, and the microheterogeneity of the GST isozymes was shown by high-resolution native isoelectrofocusing (IEF) in polyacrylamide slab gels and by SDS-PAGE. Five subunits were identified: QL1 (30.5 kDa), QL2 (27.2 kDa), QL3a (26.8 kDa), QL3b (26.5 kDa), and QL4 (25.5 kDa). Western blot analysis revealed that QL1 and QL2 reacted with antibodies raised against the rat Mu class GSTs (Yb1 and Yb2), and QL3a and QL3b reacted with those raised against the Alpha class (rat Ya and mouse a). Substrate specific activity of each isoform was determined with CDNB, DCNB, CuOOH, EA, t-PBO, ASD, and t-SO. QL3a and QL3b have high reactivity toward CuOOH, while QL1 and QL2 showed high activity toward t-SO. The N-terminal amino acid sequence of QL2 was identical to that of the chicken Mu class GST subunit CL2. However, no sequence was obtained with QL1 due to possible N-terminal blockage.

The optimum decision rules for the oddity task

This paper presents the optimum decision rule for an m-interval oddity task in which m-1 intervals contain the same signal and one is different or odd. The optimum decision rule depends on the degree of correlation among observations. The present approach unifies the different strategies that occur with "roved" or "fixed" experiments (Macmillan & Creelman, 1991, p. 147). It is shown that the commonly used decision rule for an m-interval oddity task corresponds to the special case of highly correlated observations. However, as is also true for the same-different paradigm, there exists a different optimum decision rule when the observations are independent. The relation between the probability of a correct response and d' is derived for the three-interval oddity task. Tables are presented of this relation for the three-, four-, and five-interval oddity task. Finally, an experimental method is proposed that allows one to determine the decision rule used by the observer in an oddity experiment.

On measuring psychometric functions: a comparison of the constant-stimulus and adaptive up-down methods

Psychometric functions were obtained using the conventional constant-stimulus method and an adaptive up-down method, for both computer-simulated and human observers. Except when the stimuli are closely placed, psychometric functions obtained with the adaptive method are as accurate as those obtained with the constant-stimulus method. Empirically, the adaptive method has some potential advantages owing to its ability to automatically concentrate the trials within the dynamic range of the psychometric function. It needs no pilot measurements for setting the signals as required by the constant-stimulus method. Furthermore, following a marked change in the underlying psychometric function, the distribution of the trials is automatically readjusted. Thus, on the basis of empirical considerations, the adaptive method is a better choice than the constant-stimulus method for measuring psychometric functions.