Recombinant TSH in ablative therapy and follow-up of patients with differentiated thyroid carcinoma

The studies evaluating the efficacy and safety of recombinant TSH in the ablative therapy and follow-up of patients with differentiated thyroid carcinoma by serum thyroglobulin (Tg) measurement and iodine scanning were reviewed in this article. Recombinant TSH is comparable to hypothyroidism in the generation of Tg and in the execution of iodine-131 whole-body scanning, with the advantage of sparing patients from the symptoms of hypothyroidism and from impaired quality of life induced by levothyroxine withdrawal, in addition to a reduced exposure to elevated TSH and shorter absence from work, with recombinant TSH being the preparation indicated for the diagnosis of metastases in both low risk (Tg after recombinant TSH) and moderate or high risk patients (Tg and iodine-131 scanning after recombinant TSH). In the case of ablative therapy, the results are promising when using a dose of 100 mCi for remnant ablation, but hypothyroidism is still preferred, except for patients in whom the desired TSH elevation after levothyroxine withdrawal is not achieved, patients with base diseases that are aggravated by acute and severe hypothyroidism (severe heart and lung disease, coronary disease, compromised renal function, history of psychosis due to myxedema), patients debilitated by advanced disease, and elderly individuals. The studies also show that the administration of recombinant TSH is safe, with few mild or moderate adverse effects.     

Hyperthermic reactions induced by orexin A: role of the ventromedial hypothalamus

This experiment tested the involvement of the ventromedial hypothalamus (VMH) in the sympathetic and hyperthermic reactions induced by an intracerebroventricular (i.c.v.) injection of orexin A (1.5 nmol). In the first part of the experiment, the firing rate and cytochrome oxidase activity of the VMH neurons, and the colonic temperature were monitored in 12 urethane-anaesthetized rats before an i.c.v. injection of orexin and over a period of 2 h after the injection. Orexin induced an increase in the firing rate, colonic temperature and cytochrome oxidase activity. A group of 12 rats was used as a control: saline, but not orexin, was injected. No modifications in the firing rate, cytochrome oxidase reactivity and colonic temperature were noted. In the second part of the experiment, 12 rats were anaesthetized and lesioned bilaterally in the VMH with an injection of ibotenic acid. Sham lesions were carried out in 12 control rats. After 48 h, all animals were anaesthetized with ethyl-urethane. The firing rates of the sympathetic nerves to interscapular brown adipose tissue (IBAT), along with IBAT and colonic temperatures and heart rate were monitored before and over a period of 2 h after an i.c.v. injection of orexin or saline in the lesioned and sham-lesioned rats. Orexin increased the sympathetic firing rate, IBAT and colonic temperatures and heart rate in the sham-lesioned rats. These increases were reduced by lesion of VMH. Saline did not induce any modification. These findings indicate that the VMH is involved in the control of the orexin-induced hyperthermia.     

Abnormal pH-sensing of platelet Na+/H+ exchanger in patients with cardiac syndrome X

An enhanced activity of Na⁺/Li⁺ countertransport, studied as a surrogate of Na⁺/H⁺ exchanger, has been described in red blood cells of patients with cardiac syndrome X. In this study we investigated whether abnormalities in the activity of platelet Na⁺/H⁺ exchanger (NHE) also existed in syndrome X patients and whether such abnormality was associated with platelet activation. Platelet NHE activity was evaluated in 21 syndrome X patients and 18 controls by measuring the pH recovery in platelets after acid loading and/or thrombin stimulation. The linear correlation existing between the initial intracytoplasmic pH (pH_i) values and the maximal velocity of pH recovery allowed to calculate the values of slope and intercept at pH_i=6.6 (I_pH6.6) for each individual. Urinary excretion of the major TXB₂ metabolite, 11-dehydro-TXB₂ was measured in 15 syndrome X patients and 15 controls. The acidification-induced NHE activity resulted significantly higher in syndrome X patients compared to controls. Indeed, slope values were 0.75±0.29 and 0.5±0.23 min⁻¹ in patients and controls, respectively (P=0.01), while I_pH6.6 values were 0.24±0.1 and 0.17±0.1 ΔpH/min (P=0.04). The thrombin-stimulated NHE activity, however, was not different in the two groups and no significant difference in the urinary excretion of 11-dehydro-TXB₂ between patients and controls (median 920 vs. 765 pg/mg creatinine, respectively) (P=0.32) was also found. Thus our data demonstrate an alkaline shift in pH-dependence of platelet NHE of syndrome X patients. This abnormality does not seem to be associated with increased platelet activation.     

Endoscopic resection of sinonasal malignancies: a preliminary report

BACKGROUND: A minimally invasive endoscopic approach for the management of sinonasal malignancy offers several advantages including excellent illumination, maximal preservation of uninvolved vital structures, and sparing of facial incisions. The purpose of this study was to evaluate the outcome and morbidity of endoscopic resection with or without combined radiotherapy and/or chemotherapy. METHODS: Forty-seven patients with sinonasal malignancy were diagnosed and/or treated with an endoscopic approach at The Cleveland Clinic Foundation and The University of Pennsylvania Medical Center from 1996 to 2003. Nineteen patients fulfilled the study criteria and had a minimally invasive endoscopic resection. Fifteen patients were treated with curative intent and four patients underwent palliative resection. RESULTS: The mean age was 56.9 (9-78 years) years and the mean follow-up period was 26.4 months. Combined radiation with or without chemotherapy pre- or postoperatively was given to 15 of 19 (78.9%) patients. Thirteen patients were resected strictly with an endoscopic approach and six patients were resected in combination with neurosurgery. There were no peri- and postoperative deaths. The local recurrence (LR) rate was 26.3% (5/19) and the distant metastasis rate was 15.8% (3/19). Overall survival rate (OS) was 78.9% (15/19) at a mean follow-up duration of 32.1 (4-74 months) months. The disease-free survival (DFS) rate was 68.4% (13/19) by clinical, endoscopic, and radiographic surveillance at a mean follow-up duration of 33.1 months. Patients treated with curative intent had LR, OS, and DFS rates of 21.4, 85.7, and 85.7%, respectively, and the patients treated for palliation had LR, OS, and DFS rates of 40, 60, and 15%, respectively. CONCLUSION: Minimally invasive endoscopic resection of sinonasal malignancy in combination with adjunctive therapies reduces treatment morbidity and yields LR, OS, and DFS rates that are comparable with traditional anterior craniofacial approaches.     

Reliability of the IOLMaster in measuring corneal power changes after photorefractive keratectomy

PURPOSE: To test the accuracy of the IOLMaster (Carl Zeiss) in detecting corneal power changes after photorefractive keratectomy (PRK). SETTING: Department of Ophthalmology, 2nd University of Naples, Naples, Italy. METHODS: Two hundred twenty-five consecutive eyes that had PRK (mean -5.13 diopters [D] +/- 2.98 [SD] [range +0.25 to -16.25 D]) were analyzed. The data included preoperative and postoperative (1, 3, and 6 months) subjective refraction and computerized keratometry. Statistical analysis was performed to determine the correlation between the changes in the subjective refraction at the corneal plane and the changes in keratometry. RESULTS: The mean difference between the changes in refraction and the measured corneal changes was 0.75 +/- 1.13 D (range -3.84 to +7.68 D) at 1 month, 0.92 +/- 1.10 D (range -0.87 to +7.93 D) at 3 months, and 0.75 +/- 0.98 D (range -1.70 to +3.85 D) at 6 months. The difference was significant (P<.001). CONCLUSION: Automated keratometry provided by the IOLMaster did not accurately reflect the effective refractive changes after PRK, particularly in eyes that had a high dioptric treatment.