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2,2'-Azobis(2-amidinopropane) dihydrochloride (AAPH), a free radical-generating azo compound, is gaining prominence as a model oxidant in small molecule and protein therapeutics, namely for its ability to initiate oxidation reactions via both nucleophilic and free radical mechanisms. To better understand its degradation pathways, AAPH was degraded at 40°C in aqueous solutions over a wide pH range. Samples were analyzed via liquid chromatography-ultraviolet spectroscopy and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The thermal decomposition rate of AAPH to form radical species averaged 2.1 × 10(-6) s(-1) and did not vary significantly with pH. The hydrolysis rate increased exponentially with pH, showing hydroxide ion dependence. A mechanism for AAPH hydrolysis is proposed. The LC-MS/MS results provided evidence that the alkoxyl radical is a major radical species in solution. The LC-MS/MS results also showed a radical disproportionation reaction and enabled the generation of an overall reaction scheme showing the various side and termination products of AAPH degradation., (Copyright © 2011 Wiley-Liss, Inc.)

Influenza vaccines must be revised constantly on almost a yearly basis because of the sequential mutations (antigenic drift) that occur as the virus responds to immunologic pressure. New, high yield (hy) reassortant viruses have proved essential to meet production needs for the supply of new vaccines. We have devised a method for simple, rapid and precise identification of the principal influenza A virus RNA segment (RNA 7) associated with hy and transferred from the hy donor virus, A/PR/8/34 (H1N1). The method entails the use of a single restriction enzyme, Bsgl, in analysis by restriction fragment length polymorphism (RFLP) of reverse transcriptase-polymerase chain reaction (RT-PCR)-generated DNA amplicons. The method clearly distinguishes the RNA coding for the M proteins of the donor virus from that of representative and epidemiologically significant human wild type viruses of the past 60 years. In the course of this methodological study further evidence has been found of the variability of the so-called 'invariant' and stable M1 and M2 proteins of the virus. Another finding of potentially basic significance that merits further study is the occurrence of a consistent change at the same amino acid (aa) site of the donated RNA 7 upon its transfer to reassortant viruses.

Gap junction-mediated communication is required for normal cellular growth and differentiation. As cancer is thought to be a manifestation of the breakdown of cell-cell communication, with the concomitant loss of growth control, it would be expected that alterations in the primary structure, processing, oligomerization or trafficking of connexin (cxn) molecules would have a profound effect on the neoplastic process. Here we a present a preliminary immunohistochemical and molecular analysis of cxn 43 expression in prostatic epithelial cells from resected human tissue. Our data indicate that benign prostatic epithelial cells express cxn 43 protein, but that this expression is diminished in more advanced, anaplastic cancer cells. These data suggest that decreased connexin expression is not involved in the initiation of prostate cancer, but rather occurs during the progression of the disease.

Tumor invasion of the carotid artery is a potential indication for brachytherapy, which delivers a high dose of irradiation to residual tumor while limiting the dose to adjacent healthy tissues. The tolerance of carotid-sheath contents to varying doses of brachytherapy, however, has not been clearly established. In order to evaluate brachytherapy effects on carotid-sheath contents, after-loading catheters were implanted bilaterally in 3 groups of 6 rabbits each (18 rabbits). Iridium 192 brachytherapy doses of either 5000 cGy (rad), 9000 cGy, or 13,000 cGy were delivered unilaterally, with the contralateral neck serving as a nonirradiated control in each animal. There were no carotid ruptures and wound healing was normal. Two animals from each group were killed at 6, 20, and 48 weeks. Even at the highest dose (13,000 cGy), nerve conduction studies performed on the vagus nerve prior to sacrifice revealed no increased latency, histologic changes were minimal, and carotid arteries were patent. These observations suggest that the carotid-sheath contents in healthy rabbits could tolerate high doses (up to 13,000 cGy) of low-dose-rate interstitial brachytherapy without complications.

Angioedema that occurs in the head and neck may be a serious and possibly life-threatening condition. We present two cases of oropharyngeal angioedema associated with the use of angiotensin-converting enzyme inhibitors in patients with no underlying renal failure. Angiotensin-converting enzyme-inhibiting agents are now commonly used to control hypertension. Treatment of acquired angioedema is directed first at protecting the airway by careful observation, intubation, or if necessary, tracheostomy. The causative agent is withdrawn, and the patient is treated with antihistamines and steroids until the acute episode resolves. Although not used in our patients, the treatment of angioedema with subcutaneous epinephrine has been described. As more patients are treated with angiotensin-converting enzyme inhibitors, it becomes essential for the otolaryngologist to become aware of this potentially life-threatening complication.

Serial measurements of blood pressure, body weight, food and water intake, and salt and water excretion were compared in two groups of spontaneously hypertensive rats (SHR) over a 12-day period: control SHR (n = 11) and a group (n = 9) which received supplementary 5-hydroxytryptophan (5-HTP; 2 mg/ml) in its drinking water. During the final 4 days of study, both groups received additional oral carbidopa (50 mg/kg twice a day) to inhibit peripheral, but not brain aromatic L-amino-acid decarboxylase (LAAD), an enzyme necessary to the formation of 5-hydroxytryptamine (5-HT, serotonin) from 5-HTP. 5-Hydroxytryptophan increased urinary 5-HT and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) markedly; following carbidopa, urinary 5-HT, and to a lesser degree urinary 5-HIAA, decreased, whereas brain 5-HT and 5-HIAA increased. Spontaneously hypertensive rats treated with 5-HTP plus carbidopa had significantly lower blood pressure levels, lower pulse rates, reductions in food and water intake, salt and water excretion, and a loss of body weight, when compared with the control SHR. These data indicate that enhanced brain formation of 5-HT can give rise to metabolic and circulatory responses with a resultant lowering of blood pressure.

Congenital absence of a main pulmonary artery is a rare anomaly. Most patients without associated congenital cardiac abnormalities are asymptomatic, and the diagnosis is first suggested by the appearance of the involved lung on a routine chest roentgenogram. The ipsilateral lung will be smaller than normal, and the contralateral lung will be overinflated and may herniate across the midline. We describe eight children with unilateral pulmonary arterial atresia (seven on the right side, four of whom were without associated cardiac anomalies).

Among the various diagnostic modalities that have been recommended for preoperative assessment of the patient with laryngeal carcinoma is computed tomography. While good overall correlation between CT findings and operative findings has been noted, a significant number of false positives and false negatives have been found, particularly with regard to cartilage invasion and lymphadenopathy. We compared the findings of direct laryngoscopy, palpation of the neck, and CT with pathologic specimens in 29 patients who underwent surgery for carcinoma of the larynx. We found that CT scanning underestimated the extent of neoplastic involvement in over half the cases. With respect to cartilage invasion we determined a significant number of false-negative findings. Computed tomographic scanning was equivalent to palpation in predicting cervical metastasis. Our findings indicate that the role of CT scanning may be more limited than previously acknowledged, particularly in patients for whom nonconservation surgery is planned.

Isolated cutaneous cryptococcosis developed in a 62-year-old white man with an idiopathic deficiency of T-lymphocytes. The patient was healthy, except for the cutaneous infection, and displayed no other evidence of an immunodeficiency disorder. An immunologic workup should be conducted in all patients with cryptococcal infection, regardless of their apparent health status.

Seven hundred sixty-one patients with operable differentiated thyroid carcinoma were treated between 1931 and 1970. Median follow-up time was 18 years and ranged from 5 to 40 years. Sixty-three percent of the patients were followed more than 15 years, and 46% were followed more than 20 years. Because resections usually spared sufficient thyroid tissue for homeostasis, thyroid hormone was not routinely prescribed after operations performed before 1960. Altogether 244 patients with papillary carcinoma and 76 patients with follicular carcinoma received thyroid hormone, while 296 patients with papillary carcinoma and 45 patients with follicular carcinoma did not receive thyroid hormone after operation. With papillary carcinoma, 14% of men greater than 40 and women greater than 50 years of age (high risk) but only 2% of men less than or equal to 40 years of age and women less than or equal to 50 years of age (low risk) died of disease (P 0.0001). Twenty-six percent of high-risk but only 4% of patients with low-risk follicular cancer died (P 0.0001). However, there was no statistically significant improvement in survival times with use of thyroid hormone when patients were categorized by risk group and pathology. These data support the importance of age and sex in previously described risk groups; these factors supersede the effects of adjuvant treatment. This absence of effect on survival times calls into question current recommendations for routine use of thyroid hormone after surgical therapy. Conceptually, such absence of adjunctive hormone effect on survival time after operation is similar to hormonal effects in other endocrine cancers, which may nevertheless provide good palliation in some cases.

Records of 792 patients with differentiated thyroid carcinoma seen at the Lahey Clinic Foundation over a 40-year period were analyzed; 631 patients had a minimum followup period of 15 years. Differentiated types currently constitute nearly 90% of thyroid carcinomas. The clinical presentation has improved substantially through the years, and the results of treatment generally have improved. The per cent of patients with primarily incurable and locally unresectable disease or distant metastases has decreased from 7% before 1950 to 1% currently, and this group resulted in almost one third of the total fatalities and one half of fatalities within the first 5 years after treatment. Clear relationships were demonstrated between older age, men, extraglandular extension, blood vessel invasion, major capsular involvement, multifocal disease, and higher mortality rates. Lymph node metastases were found to exert a protective effect in all categories of disease analyzed, and this effect was directly related to the number of lymph node metastases present such that no deaths occurred in those patients who had more than 10 node metastases. Surgical treatment recommended is subtotal thyroidectomy for patients at high risk of death from disease as defined by combinations of age, sex, and extraglandular extension. Patients at low risk or with small carcinomas can be treated satisfactorily by lobectomy. Lymph node resections should be of a limited type or a modified neck dissection and should be performed only therapeutically. No improvement, as judged by mortality or recurrence rates, could be demonstrated by the use of radio therapy after surgery, and its use should be discouraged. Thyroid hormone administered for suppression of endogenous thyroid-stimulating hormone production improved mortality rates significantly in patients with papillary and mixed forms of carcinoma in all age groups but did not affect survival in patients with follicular carcinoma of the thyroid.20