Redifferentiation and induction of tumor suppressors miR-122 and miR-375 by the PAX8/PPARγ fusion protein inhibits anaplastic thyroid cancer: a novel therapeutic strategy.

Anaplastic thyroid cancer (ATC) is an aggressive, fatal disease unresponsive to traditional therapies, generating a need to develop effective therapies. The PAX8/PPARγ fusion protein (PPFP) has been shown to favorably modulate tumor growth in follicular thyroid cancer, prompting our evaluation of its efficacy to inhibit ATC cell and tumor growth in vitro and in vivo. PPFP was constitutively expressed in five ATC cell lines: BHT-101, FRO, C-643, KTC-2 and KTC-3, and inhibited cell growth in four of five cell lines and xenograft tumor growth in four of four cell lines. PPFP-mediated growth inhibition involved multiple mechanisms, including upregulation of miR-122 and miR-375, associated with decreased angiogenesis and AKT pathway inactivation, respectively. Also, PPFP expression resulted in marked increase of thyroid-specific marker transcripts, including PAX8, thyroid peroxidase (TPO), sodium iodide symporter (NIS) and thyroglobulin, to varying degrees by activating their respective promoters, suggesting that PPFP induced cellular redifferentiation. Functional studies demonstrate that increased NIS messenger RNA is not associated with increased 125I uptake. However, ectopic expression of wild-type NIS-induced perchlorate-sensitive iodine uptake, suggesting that endogenous NIS in ATC cell lines is defective. As current treatment for ATC is only palliative, overexpression of PPFP may offer a novel therapeutic strategy for the treatment of ATC.

Onset of auditory deprivation.

The purpose of this investigation was to study further the assertion that auditory function deteriorates in the unaided ear of individuals with sensorineural hearing loss (SNHL) who receive monaural hearing aid fittings. The word recognition scores (WRSs) of 77 monaurally and 65 binaurally fitted subjects with symmetric bilateral SNHL were examined at 1, 3, and 5 years post hearing aid fitting. The deterioration in auditory function was defined as a significant change in the WRSs for Northwestern University Auditory Test No. 6 (NU-6) materials in the unaided ear of individuals fitted with a monaural hearing aid arrangement. Analyses of the data indicate that 25 percent of the monaurally fitted subjects experienced a significant change in the WRSs of their unaided ears, whereas only 6 percent of the binaurally fitted subjects experienced a significant change in the WRSs of either ear. Auditory function does deteriorate in the unaided ears of individuals with SNHL who receive monaural hearing aid fittings. Moreover, the decline in auditory function of the unaided ear does not result from a decrease in hearing sensitivity.

Is the unaided ear effect independent of auditory aging?

As a group, adults with bilateral symmetric sensorineural hearing loss (SNHL) who receive a monaural hearing aid fitting experience a progressive decline in their word recognition score (WRS) for monosyllabic word materials in the unaided ear but not in the aided ear. However, adults with binaural fittings do not demonstrate a similar deterioration in their WRS. In an effort to determine the role of senescent auditory changes on the unaided ear effect, a retrospective investigation was carried out on a group of hearing aid wearers. Using NU-6 to assess the WRS, this investigation attempted to answer the following question: is the unaided ear effect related to asymmetric senescent auditory changes? The present results indicate that the unaided ear effect is not related to such an asymmetric effect since it is shown to occur in adults with SNHL whether in the fourth or seventh decade of life.

Effectiveness of three central auditory processing (CAP) tests in identifying cerebral lesions.

The effectiveness of three central auditory processing (CAP) tests was evaluated using clinical decision analysis (CDA) procedures. The tests under study were the Dichotic Digits Test (DDT), the Auditory Duration Patterns Test (ADPT), and the P300 evoked potential test (P300). Subjects with normal hearing, sensorineural hearing loss (SNHL), and central lesions provided the data for CDA analyses. To identify the most effective test, we used the conventional CDA parameters of hit rate (sensitivity), false-positive rate (1 - false-positive rate = specificity), and A' (test performance at specific hit/false-positive combinations). Further, we illustrated the extension of the conventional CDA parameters to posterior probability determination, which incorporates disorder prevalence to compute the likelihood of a patient having a disorder when a test result is positive (Pr[D/+]) or not having a disorder when the test result is negative (Pr[N/-]). Last, we used the CDA parameter of hit rate and disorder prevalence to determine cost effectiveness.

Validity of the ipsilateral acoustic reflex as a screening parameter.

Historically, the ipsilateral acoustic reflex (IAR) has played a prominent role in middle ear screening protocols. However, in 1990, the American Speech-Language-Hearing Association's revised guidelines, "Screening for Hearing Impairment and Middle Ear Disorders," deleted the IAR as a screening parameter. This decision was based on studies that demonstrated that the inclusion of the IAR resulted in a high false-positive rate without adding to the hit rate and thus was a major contributor to over-referral. However, other investigations demonstrated the converse, that the IAR is a sensitive and contributory measure in a screening protocol. Our data suggest that the conflicting results are due to different operating systems in the middle ear analyzers that were used to elicit the IAR. Based on our findings, an optimal IAR screening protocol would use a pulsed elicitation immittance system (multiplexing circuit) and a maximum intensity level of 105 dB HL. Further, if the IAR screening were to be carried out using an automated (programmed) immittance system with an equivalent volume change criteria for IAR detection, the equivalent volume change of > or = 0.03 ml is recommended.

Escherichia coli verotoxin binding to human paediatric glomerular mesangial cells.

Haemolytic uraemic syndrome (HUS) remains the leading cause of acute renal failure in children. Although an Escherichia coli-produced verotoxin (VT) has been implicated in the pathogenesis of HUS, the precise mechanisms of disease are not well defined. We hypothesise that the pathogenesis of renal failure in HUS includes the binding of E. coli VT to the glomerular mesangial cell, with consequent effects on renal function. Using human paediatric mesangial cells, we studied the binding and biological effects of the purified verotoxin VT-1. We isolated, purified and characterised paediatric glomerular mesangial cells. The mesangial cells were characterised by their immunoreactivity with both smooth muscle actin and vimentin antibodies, and lack of immunoreactivity with cytokeratin or factor VIII antibodies. Using an fluorescein isothiocyanate-conjugated VT (10(-7)-10(-8) M), we demonstrated specific binding to the mesangial cell membrane by immunofluorescence microscopy. We also demonstrated a dose-dependent inhibition of mesangial cell mitogenesis at concentrations from 10(-9) to 10(-17) M. Our data demonstrate that VT-1 binds to paediatric human glomerular mesangial cells and this binding results in specific biological actions, including an inhibition of cell mitogenesis.

Airbag deployments: the Canadian experience.

Transport Canada is undertaking an in-depth study of motor vehicle collisions involving airbag deployments. University-based collision investigation teams across Canada are used to collect crash data. The primary objective of the study is to gain a better understanding of the injuries and the injury mechanisms associated with airbag deployments among both restrained and unrestrained occupants. Preliminary results show an exceptionally high level of seatbelt use in conjunction with the supplemental air cushion restraints. Most crashes are, however, of only minor to moderate severity, in which the seatbelt systems alone would be expected to provide adequate occupant protection. Initial findings indicate that, at the lower end of the collision severity spectrum, deployment of an airbag may, in some circumstances, increase the overall likelihood of injury to a restrained occupant. This suggests that the current deployment threshold is set too low, at least for belted occupants.

Acoustic neuroma in an adolescent without neurofibromatosis: case study.

When acoustic neuromas are found in younger age groups, they are typically bilateral and associated with neurofibromatosis (NF). A unilateral acoustic neuroma in a child or adolescent without NF is rare. We report audiometric, auditory brainstem response (ABR) and magnetic resonance imaging (MRI) data for a 15-year-old male with an acoustic neuroma but without associated NF. The patient was seen for audiologic assessment on three separate occasions over a period of 5 years. The first two assessments produced unremarkable audiometric and immittance data. The third assessment, subsequent to a failed school hearing screening, demonstrated a flat unilateral sensorineural hearing loss, unilateral absent acoustic reflexes, and abnormal bilateral ABR recordings. MRI with contrast demonstrated a unilateral mass extending out of the internal auditory meatus. Microscopic examination of the removed tumor confirmed a vestibular schwannoma. An enhanced MRI 3 years post neuroma removal demonstrated no evidence of tumor regrowth and no evidence of other neoplasms. ABR recordings for the uninvolved ear continued to demonstrate neural synchrony as evidenced by normal absolute wave latencies; however, the III-V and I-V interwave latencies remained extended beyond the 99th percentile. Postoperatively, the young man was fitted with a high gain in-the-ear hearing aid in the involved ear, which he has continued to wear on a daily basis for the past 3 years.

Effectiveness of transient-evoked otoacoustic emissions (TEOAEs) in predicting hearing level.

The purpose of the present investigation was to (1) determine the short-term test-retest reliability of the transient-evoked otoacoustic emission (TEOAE) parameters of echo level and reproducibility, as produced by the Otodynamic's ILO88 system; and (2) assess the ability of the ILO88 parameters of frequency spectrum, echo level, and reproducibility to identify ears with sensorineural hearing loss. Our results show that the short-term test-retest reliability for both echo level and reproducibility is excellent, reflecting the stability of TEOAEs and the low measurement error associated with the procedure for obtaining TEOAEs. The data suggest, however, that frequency-specific hearing levels (HLs) cannot be accurately predicted from the analogous frequencies depicted in the frequency spectrum produced by the ILO88 system. Although frequency-specific HLs cannot be predicted from the frequency spectrum, the parameters of echo level and reproducibility will clearly separate individuals with HLs < or = 20 dB from individual with HLs > 20 dB for the octave frequencies of 500-4000 Hz. An echo level of < 6 dB and/or a reproducibility value of < 70 percent are associated with HLs > 20 dB between 500 and 4000 Hz. The combination criterion of an echo level of < 6 dB and a reproducibility value of < 70 percent appears to be a suitable screening method for identifying adult ears with an average HL of > 20 dB.

Monaural hearing aid effect: case presentations.

A phenomenon associated with a monaural hearing aid fitting has previously been identified. In some individuals with bilateral sensorineural hearing loss (BSNHL), the speech-recognition score (SRS) of the unfitted ear deteriorates over time. Nine subjects with BSNHL who chose a monaural hearing aid fitting are chronicled from the time of their initial hearing fitting to the time where the SRS of the unfitted ear dropped below the lower limit of the 95 percent critical difference value. All nine of the subjects were fitted with binaural amplification at the time of the significant change in the SRS. Five of the subjects retained the binaural amplification arrangement while three of the subjects returned their second hearing aid after a "30 day trial," and one subject stopped wearing the second hearing aid 8 months after the binaural fitting. All the subjects who chose to utilize the binaural arrangement had their SRS return to within the 95 percent critical difference range as did two of the individuals who chose to retain the monaural arrangement.

Lipopolysaccharide alters suckling rat liver glycogenolysis.

Gram-negative sepsis/septic shock in the newborn continues to be a major medical problem, causing high mortality. Hyperglycemia followed by hypoglycemia is a common symptom in endotoxic shock. However, the mechanism of newborn glucoregulatory response to endotoxin has not been well understood. Paradoxically, monocyte-phagocytes can contribute to shock by overwhelming secretion of cytokines and also host defense by detoxifying endotoxin. Since monocyte-phagocyte function is immature in the newborn, this study was performed to evaluate Kupffer cell's role in liver glycogenolysis during endotoxic shock. Endotoxin (LPS) induced hyperglycemia in 10-day-old rats, and increased net glucose output in the isolated perfused liver. 1) Cytarabine decreased Kupffer cell function (decreased hepatic colloid carbon uptake) and blunted LPS-increased liver net glucose output in the Cytarabine + LPS-treated group (104 +/- 4 vs. 146 +/- 3 micrograms/min/g wet liver in the LPS-treated group: P < .001). 2) Indomethacin (IND) suppressed LPS-induced liver net glucose output in the LPS + IND-treated group (133 +/- 5 vs. 146 +/- 3 micrograms/min/g wet liver, P < .05). Thus, prostaglandins were suggested to contribute to glycogenolysis in the 10-day-old rat liver. 3) Phorbol 12-myristate 13-acetate (PMA) increased liver net glucose output (166 +/- 4 micrograms/min/g wet liver), and H-7, a protein kinase C inhibitor, blunted PMA-induced liver glucose output (140 +/- 2 micrograms/min/g wet liver, P < .05). H-7 enhanced LPS-induced liver net glucose output (196 +/- 9 micrograms/min/g wet liver, P < .01). Therefore, protein kinase C may not be the dominant cell signaling system for LPS stimulation in suckling rat Kupffer cells.

Lactic acid changes during and after hypothermic cardiopulmonary bypass in infants.

Infants undergoing open-heart surgery with hypothermic cardiopulmonary bypass experience markedly elevated lactate and glucose levels. Reports in infants less than 10 kg show the elevated lactate to be progressive during the operative period. The pathogenesis of the hyperglycemia is not clear but may be caused by excess glucose administration, inadequate insulin response, or glucose regulatory hormone levels of glucagon, cortisol, and growth hormone. The purpose of this study is to confirm these findings and to investigate their pathogenesis. Serial blood samples were taken preoperatively, intraoperatively, and postoperatively during hypothermic cardiopulmonary bypass in nine infants of less than 10 kg. Samples were analyzed for levels of lactate, glucose, and regulatory hormones insulin, growth hormone, glucagon, and cortisol. Our study did not show a progressive accumulation of lactate. The elevated lactate level appears to come from the pump prime solution. The hyperglycemia is also from the pump prime solution, and there do not appear to be elevated levels of regulatory hormones intraoperatively. Insulin response during hypothermia is blunted; however, on rewarming the patient in the immediate postoperative period, a brisk insulin response is seen. The changes in levels of lactate and glucose and the regulatory hormones return to baseline at 24 hours with no further significant changes in the next 48 hours.

Assessment of renal function in the young. Special considerations.

Infants are born in a state of renal insufficiency and have varying degrees of maturity of tubular processes. This is even more striking in premature infants. This article presents a review of glomerular and tubular function assessment with particular attention to factors that impact these developmental and maturational factors.

Glycosuria and maternal licking in rats.

Maternal anogenital licking (MAGL) has been studied to understand the mechanism of maternal behaviour. The present study showed that rats had glycosuria at the concentration of 18-20 mg/dl and glucose was the preference of postpartum rats. MAGL increased on suckling rats separated for 24 h. However, wiping anogenital region attenuated the increase of MAGL. Therefore, glucose preference of postpartum rats may be involved in MAGL.

Diltiazem treatment of endotoxic shock in suckling rats.

Gram-negative sepsis septic shock continues to produce significant mortality and therefore remains a major medical problem. Vasodilators have been studied in the treatment of circulatory shock. However, the effectiveness of calcium channel blockers in the treatment of newborn endotoxic shock has not been well documented. In the present study, diltiazem, a calcium channel blocker, and nitroprusside, a vasodilator, were used for the treatment of endotoxic shock in 10-day-old rats. Mortality rate, hemodynamics, and glucose metabolism were monitored. Diltiazem at a dose of 0.3 mg/kg attenuated the hypotension, bradycardia, hypoglycemia, and lactacidemia in newborn endotoxic shock. Diltiazem treatment resulted in reduced 24-hour mortality. However, 0.6 mg/kg diltiazem enhanced the hypotension, bradycardia, and lactacidemia in endotoxic shock. Nitroprusside blunted the hypoglycemia and decreased the mortality rate among rats with endotoxic shock. Afterload reduction may be responsible for the beneficial effects of 0.3 mg/kg diltiazem and nitroprusside. Diltiazem at a dose of 0.3 mg/kg reduced the lactacidemia of endotoxic shock more than nitroprusside. Therefore the effects of diltiazem may be due not only to afterload reduction but also to inhibition of cellular calcium influx. We conclude that 0.3 mg/kg diltiazem and 1.0 mg/kg nitroprusside are beneficial for the treatment of endotoxic shock in newborn rats.

Elevated lead levels in a patient with sickle cell disease and inappropriate secretion of antidiuretic hormone.

A five-year-old girl with known sickle cell disease presented with severe hyponatremia and findings compatible with syndrome of inappropriate secretion of antidiuretic hormone (SIADH). She was found to have lead levels in the Class III category. By exclusion, we postulated that the SIADH was in some way related to the high lead levels, since this was the only abnormality the patient exhibited. The toxic lead levels and the elevated vasopressin levels rapidly responded to dimercaprol and calcium EDTA chelation therapy.