Absence of coactivation in the motor component: evidence from psychophysiological measures of target detection

Previous research examining response time has supported coactivation under certain conditions. Other research has found more forceful responses to redundant-target than to single-target displays, suggesting coactivation in the motor component. The authors tested for motor coactivation using response time, response force, and other psychophysiological measures. Experiments 1 and 2 showed that response force is determined by the number of stimuli, not the number of targets, when target-distractor discriminations are required. In Experiment 3, 1 stimulus was presented on each trial, and the number of target features was varied. The response time results showed that coactivation occurred somewhere in the information-processing system, but no evidence of motor coactivation was found using any psychophysiological measure. These data disconfirm the motor-coactivation hypothesis for tasks that require visual discriminations.

Synthesis of a lacI gene analogue with reduced CpG content

A lacI gene analogue with reduced CpG content has been synthesized. Codon usage in the lacI gene was manipulated to remove most CpG sites (82/95; 86%) while maintaining wild-type amino acid sequence. The double-stranded gene sequence was synthesized using standard beta-cyanoethyl phosphoramidite chemistry and subsequently cloned into pBR322. Bacterial promoter sequences with different levels of activity were attached upstream of the modified coding region to study its expression in E. coli. Production of lacI protein was confirmed in a lacI- E. coli strain by Western blot analysis and by measuring repression of the lacZ gene with the chromogenic lacZ indicator, 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-gal). The modified lacI gene construct can be used as a genetic target in cultured mammalian cells or in transgenic animals to avoid high levels of background mutation associated with methylated CpG sequences. The construction scheme described here provides a general approach to remove CpG sequences from gene constructs when methylation is undesirable.

Urethritis/dysuria after simultaneous pancreas-kidney transplantation

We evaluated the role of conservative treatment for urethritis and its complications after simultaneous pancreas-kidney (SPK) transplant. Twenty-six type I diabetic recipients with end-stage renal disease underwent SPK transplants with bladder exocrine drainage. Urethritis/ dysuria occurred in 4/26 (16%) of the patients. All cases resolved with conservative treatment that included Foley catheter and/or suprapubic cystostomy. Despite the frequency of this urological complication, none of the patients needed diversion of the exocrine drainage from the bladder to the intestine.

Prostaglandin E2 gel for cervical ripening in patients with an indication for delivery

OBJECTIVE

To determine if labor can be induced safely and efficiently in patients with a medical or obstetric indication for delivery before 41 completed weeks of gestation by pre-induction cervical ripening with prostaglandin (PG) E2 gel.

METHODS

One hundred eighteen women with confirmed indication for induction of labor before 41 completed weeks were randomized in a double-blind fashion to either intracervical PGE2 gel or placebo before induction by a standard oxytocin protocol. Data regarding the change in Bishop score, interval to complete dilation, maximal oxytocin dose required to establish labor, and route of delivery were collected. Apgar scores and umbilical artery pH were also recorded.

RESULTS

The maximum oxytocin dose required to establish progressive labor was significantly lower in the PGE2 group (10.06 +/- 8.50 versus 13.35 +/- 9.27 mU/minute, P = .014). The cesarean rate was also significantly lower in the PGE2 group (13.1 versus 31.6%, P = .016).

CONCLUSION

Pre-induction intracervical deposition of 1 mg PGE2 gel decreased the amount of oxytocin required to induce progressive labor and decreased the cesarean rate in patients who had medical or obstetric indications for delivery before 41 completed weeks. This was accomplished without negative effect on Apgar score or umbilical artery pH.

Effect of adenine methylation on the structure and dynamics of TpA steps in DNA: NMR structure determination of [d(CGAGGTTTAAACCTCG)]2 and its A9-methylated derivative at 750 MHz

At TpA steps in DNA, the adenine base experiences exceptionally large amplitude (20 degrees-50 degrees) and slow (10 ms-1 microsecond) motion [Kennedy et al. (1993) Biochemistry 32, 8022-8035] which has been correlated with transitions between multiple conformational states [Lefevre et al. (1985) FEBS Lett. 190, 37-40]. The base dynamics can be detected in one-dimensional 1H NMR spectra as excess line width of the aromatic proton resonances. The magnitude of the excess line width is temperature dependent and reaches a maximum at some temperature. In order to better understand the origin of the dynamics, we have studied the effect of N6-methylation of the TpA adenine on both the line widths and its local structure. Here, solution-state 500 and 750 MHz 1H NMR data collected on [d(CGAGGTTTAAACCTCG)]2 show that the excess line width of the TpA adenine-H2 is diminished when the TpA adenine is N6-methylated and that the line width no longer experiences a maximum as the temperature is varied. The resonances sharpen upon methylation because the amplitude of base motion is restricted due to steric effects and due to other structural changes at the TpA site. Additionally, both the TpA adenine-H8 and the exchangeable imino resonance of thymine at the TpA step were also found to have excess line width that is diminished upon N6-methylation. In order to elucidate the structural features responsible for TpA base dynamics, solution-state NMR structures of [d(CGAGGTTTAAACCTCG)]2 and its A9 N6-methylated derivative were determined at 750 MHz. Comparison of the structures shows that poor base stacking at the TpA step may contribute to, or be the origin of, its base dynamics.

Transurethral laser therapy and urinary tract infections

To date transurethral laser ablation of the prostate (TULAP) in benign prostatic hyperplasia (BPH) is the commonest form of transurethral laser surgery. The invention of the so-called "sidefire" laser fibre was the prerequisite condition for effective transurethral laser ablation of the prostate. Since the first transurethral laser ablation in human BPH was performed by Costello in September 1990, a multitude of urologists have adopted this technique. In the meantime, a great many studies have been carried out and a lot of data have been published. The initial, to some extent euphoric, enthusiasm of some urologists as well as some patients, especially in the USA and Europe, has turned into a more critical reflection. There is no doubt at all that TULAP is a feasible alternative treatment method with reasonable results. Especially in the high-risk patient, there is neither severe blood loss nor an uptake of irrigation fluid. It is also beneficial to allow unlimited treatment in patients on anticoagulant medication. Nevertheless, the value of TULAP in comparison to transurethral electroresection of the prostate (TURP), generally accepted as the "gold-standard" in the surgical therapy of BPH, remains unclear. A final assessment will only be possible when further data on mortality, short and long term morbidity and outcome with this method have been presented. Strong evidence exists that the operation can be performed without blood loss and uptake of irrigation fluid. A further advantage seems to be preservation of sexual function, especially anterograde ejaculation in the majority of patients, in comparison to the "gold-standard" TURP. In most studies, the value of TULAP is further compared with regard to the elimination of obstruction by means of pressure-flow-studies. The aspect most frequently neglected by all investigators to date is the frequency and severity of urinary tract infections (UTI) in patients in whom TULAP is performed. Basically, UTI in the form of cystitis, ascending infections such as male adnexitis or pyelonephritis, prostatitis of the remaining parts of the prostate and catheter-induced urethritis are associated with transurethral surgery in general. Certain data indicate an age-related frequency of UTI. From a rate of approximately 1% of UTI in infants, the frequency rises to 30% in the 8th decade of life. According to these data, one can expect that in a study of TULAP in high risk patients, most of whom are elderly, a large number present for surgery with a preexisting UTI. Other data demonstrate that after 4.5 days 50% and more of patients with an indwelling catheter develop an ascending UTI, although a closed urinary drainage system has been used. In most cases enterobacteriaceae, in 80% Escherichia coli, are detected. Especially in TULAP, a period of prolonged catheterisation has to be expected in the majority of patients. The risk of UTI in the perioperative phase is therefore expected to be higher. There are several higher risks and possibilities of complications in transurethral surgery in patients with UTI. Taking this into account, all our patients routinely undergo low dose antibiotic prophylactic treatment. The frequency of infections of the remaining parts of the prostate after prostatic surgery is strongly correlated to the flow characteristics in the prostatic urethra and to the amount of destruction of the prostatic tissue. Here are further reasons for a higher risk of infection after TULAP. Due to the fact that the prostatic tissue is not removed by a clear cut, but coagulated by laser beam, a rough surface due to tissue necrosis results. This is an ideal culture medium for bacteria aggravated by the disturbed laminar flow in the prostatic urethra, which favours an intraprostatic reflux of infected urine. There is evidence that UTI are the most important factor of morbidity during the first weeks after TULAP because of their bothersome symptoms.(ABSTRACT TRUNCATED)

The sampling distribution of d'

The distribution of sample estimated d's, although mathematically intractable, can be tabulated readily by computer. Such tabulations reveal a number of interesting properties of this distribution, including: (1) sample estimated d's are biased, with an expected value that can be higher or lower than the true value, depending on the sample size, the true value itself, and the convention adopted for handling cases in which the sample estimated d' is undefined; (2) the variance of estimated d' also depends on the convention adopted for handling cases in which the sample estimated d' is undefined and is in some cases poorly approximated by the standard approximation formula, (3) the standard formula for a confidence interval for estimated d' is quite accurate with at least 50-100 trials per condition, but more accurate intervals can be obtained by direct computation with smaller samples.

Synthesis of new (4-alkylamino-4'-fluoro)-diphenyl sulphones with potential biological activity

In the present work, we report the synthesis and characterization of five (4-alkylalmino-4'-fluoro)-diphenyl sulphones, four of which have not been described before. In a preliminary evaluation of their biological activity, these products showed no effect on several Gram-positive and Gram-negative bacteria and yeasts.

Effects of a decision support system on the diagnostic accuracy of users: a preliminary report

OBJECTIVES

To assess the effects of incomplete data upon the output of a computerized diagnostic decision support system (DSS), to assess the effects of using the system upon the diagnostic opinions of users, and to explore if these effects vary as a function of clinical experience.

DESIGN

Experimental pilot study. Four clusters of nine cases each were constructed and equated for case difficulty. Definitive findings were omitted from the case abstracts. Subjects were randomly assigned to one of four clusters and were trained on the DSS prior to use.

SUBJECTS

The study involved 16 physicians at three levels of clinical experience (six general internists, four residents in internal medicine, and six fourth-year medical students), from three academic medical centers.

PROCEDURE

Each subject worked up nine cases, first without and then with ILIAD consultation. They were asked to offer up to six potential diagnoses and to list up to three steps that should be the next items in the diagnostic workup. Effects of DSS consultation were measured by changes in the position of the correct diagnosis in the lists of differential diagnoses, pre- and post-consultation.

RESULTS

The DSS lists of diagnostic possibilities contained the correct diagnosis in 38% of cases, about midway between the levels of accuracy of residents and attending general internists. In over 70% of cases, the DSS output had no effect on the position of the correct diagnosis in the subjects' lists. The system's diagnostic accuracy was unaffected by the clinical experience of the users.

Longitudinal induced IL-2 mRNA monitoring in renal transplant patients immunosuppressed with cyclosporine and in unmodified canine renal transplant rejection

Immune monitoring of transplant patients to define optimal immunosuppression continues to be important, as rejection occurs despite adjustment of dosaging of CsA or even FK506 to achieve "therapeutic-range" blood levels. Because CsA is known to inhibit upregulation of IL-2 mRNA transcription, we prospectively sequentially measured (induced) IL-2 mRNA in PHA-stimulated PBMC cultures from transplant recipients of kidneys from living-related donors (n = 15) using a quantitative PCR assay, with a potential 24-hour turnaround time, to define immunologic events in real time. Reproducible individual patient sensitivity or refractoriness to CsA was determined pretransplant, by adding a range of CsA concentrations to the PBMC cultures and constructing induced IL-2 mRNA regression inhibition curves. However, this was not predictive of rejection episodes, but did correlate well with individual differences in IL-2 mRNA levels posttransplant, despite similar maintenance trough blood concentrations of CsA between patients. In this prospective study, seven patients experienced rejection episodes despite therapeutic CsA trough levels. Three of these, plus one not receiving CsA therapy, who happened to be prospectively tested at the time that rejection was clinically diagnosed, had a decrease in induced IL-2 mRNA before treatment was instituted. As a correlation to this observation in patients, induced IL-2 mRNA levels in unmodified rejection were sequentially measured in PBMC cultures in autologous vs allogeneic canine renal transplants and IL-2, IL-10, TNF-alpha, and IFN-gamma mRNA were also measured in kidney biopsies. Sequential PHA lymphoproliferation assays of [3H] thymidine incorporation on patient and dog PBMC cultures were also performed. Similar to the observations in patients, unmodified rejection in the canine renal allograft model also was accompanied by a decline of PHA-induced IL-2 mRNA in PBMCs as the serum creatinine concentrations became elevated. In the dog kidney biopsies at later phases of rejection, IL-10 mRNA levels were also significantly elevated (p = 0.032).

Transplacentally acquired antiviral antibodies and outcome in congenital human cytomegalovirus infection

The association between transplacentally acquired maternal antibodies and outcome in congenital human cytomegalovirus (HCMV) infection was investigated by analyzing antiviral antibodies in the cord blood from infants with permanent neurologic sequelae and from those without sequelae. Higher levels of antiglycoprotein B and neutralizing antibodies were observed in infants with sequelae. Infants with symptomatic infection and those with > or = 2 sequelae had higher levels of virus binding antibodies. No association between neutralizing titers and progressive hearing loss was noted. These results suggested that the development of sequelae following congenital HCMV infection was not associated with measurable deficits in the maternal antiviral antibody response. Higher levels of anti-gB and neutralizing antibodies in infants with sequelae also suggested that the natural history of this congenital infection is unlikely to be modified by the passive administration of antiviral antibodies in the postnatal period.

Transplant-associated autoimmune mechanisms in human hepatitis C virus infection

In order to define factors which are important for the development of hepatitis C virus (HCV) infection and disease in transplant patients, we examined the role of class II MHC antigen restriction in viral antigen presentation to support a hypothesis of the association of this disease with an autoimmune pathogenesis. A greater degree of histocompatibility match between these donors and their HCV-negative recipients was associated with a greater predisposition to recipient HCV liver disease (ALT elevation) posttransplant. The HCV carrier state could be identified with significant amplification of autologous mixed lymphocyte reactivity (AMLR) in both long-term hemodialysis and long-term renal transplant patients, but the AMLR was absent in end-stage liver disease patients with HCV-associated cirrhosis and was insignificantly elevated in these patients with persistent infection in the first 2 years after a new liver was transplanted. There was also a moderate reduction in autologous reactivity as well as serum HCV titers among renal transplant patients who displayed biochemical evidence of chronic liver disease as opposed to those who did not. This appeared later in the course of the disease. HCV RNA could be detected in peripheral blood mononuclear cells (PBMC) of only a portion of HCV-infected renal transplant patients and these showed significantly higher autologous reactivity. In contrast, despite the fact that observations were earlier after de novo liver transplantation, HCV RNA (i.e., earlier in the course of a new or recurrent disease process) was found in PBMC of all liver transplant recipients tested. The AMLR of noninfected laboratory volunteers could be amplified by preincubating their stimulating cells (APCs) with enriched HCV possibly in immune complex (pHCV-IC). This amplification appeared only with specific combinations of HCV strains with HLA DR serotypes. In addition, HCV-primed T cells could be generated to the virus which displayed accelerated activation kinetics. Liver infiltrating lymphocytes extracted from HCV-positive end-stage diseased livers had significantly higher proliferative and cytotoxic reactivity to autologous (HCV-infected) hepatocytes than the extracted lymphocytes responding to autologous hepatocytes from HCV-negative livers. These findings offer evidence of dynamic autoimmune mechanisms in the spectrum of progression of HCV disease and may help to predict the effect of intervention at various intervals in this progression in organ transplant recipients.

Validation of a nitrogen washout system to measure functional residual capacity in premature infants with hyaline membrane disease

A multiple-breath nitrogen washout system designed to measure lung volume in mechanically ventilated infants was validated by assessing three performance criteria: 1) accuracy of lung volume measurements in the presence of an endotracheal tube leak was assessed by comparing the measurements of functional residual capacity (FRC) in a mechanical lung model with and without airway leak; 2) in vivo accuracy was assessed in rabbits by comparing FRC measurements obtained by this system with measurements obtained by helium dilution; and 3) in vivo precision was assessed by analyzing measurements of FRC obtained in replicate measurements at different times in ventilator-dependent premature infants with hyaline membrane disease. The average difference between the measurements of FRC in a mechanical lung model with airway leak and without leak was 3.0 +/- 9.4% (mean +/- SD, P > 0.2), and no difference was greater than 20%. There was a significant correlation between the measurements of FRC in rabbits by nitrogen washout and by helium dilution (r = 0.93, P < 0.0001), and 65.4% of the paired measurements were within 20% of their average. The 95% limits of agreement within pairs of measurements by the two techniques ranged from -4.0 to + 6.5 mL/kg. FRC measured by helium dilution was slightly higher (1.3 +/- 2.7 mL/kg, P < 0.01) than FRC measured by nitrogen washout, and positive end-expiratory pressure was a significant predictor of this difference (P < 0.0001). The regression between the individual FRC measurements obtained in premature infants and the average of the other replicates was significant (r2 > 0.98, P < 0.0001). The coefficient of variation was 12.3%. These findings provide further validation of this multiple-breath nitrogen washout system for measuring FRC in premature infants during mechanical ventilation.

Cloning and expression of canine interleukin-10

We describe here the cloning of canine IL-10 cDNA (GenBank accession No. U33843) and the expression of recombinant IL-10 in a dog kidney cell line (DK6247) and Chinese hamster ovary cells (CHO). Canine IL-10 exhibits strong sequence homology to the known sequences of human, mouse, rat, and bovine genes at nucleotide and amino acid levels. The IL-10 gene, when introduced into DK and CHO cell lines, produces recombinant IL-10 that causes an inhibitory effect on allogeneic MHC-driven lymphoproliferative responses.