PARATHYROMATOSIS: A RARE CASE OF RECURRENT HYPERPARATHYROIDISM LOCALIZED BY FOUR-DIMENSIONAL COMPUTED TOMOGRAPHY.

OBJECTIVE: To present a rare case of parathyromatosis. METHODS: We present the clinical, laboratory, and imaging findings, along with a review of the literature. RESULTS: A 33-year-old man with a history of right upper parathyroid adenoma removal 5 years prior due to hyperparathyroidism was admitted for severe hypercalcemia (15.6 mg/dL; normal, 8.5 to 10.5 mg/dL) with elevated plasma parathyroid hormone (PTH) (882 pg/mL; normal, 15 to 65 pg/mL). Ultrasound, computed tomography (CT), sestamibi, and positron emission tomography scans were unremarkable; however, a four-dimensional CT (4DCT) of the neck showed an area of increased signal enhancement and hypervascularity without discrete nodule in the posterior right thyroid region. The patient underwent parathyroid surgical exploration with right hemithyroidectomy and compartment neck dissection to remove the affected tissue. PTH levels dropped to 208 pg/mL postoperatively; calcium decreased but remained elevated at 12.7 mg/dL. Pathology revealed the presence of several small nodular foci of atypical hyperplastic parathyroid tissue in the right thyroid and soft tissue in the left central neck compartment consistent with parathyromatosis. CONCLUSION: This case report represents the first-time use of 4DCT to localize parathyromatosis. Parathyromatosis is a rare but problematic cause of recurrent hyperparathyroidism. Ultrasound and 4DCT may represent the best imaging modalities for identification and perioperative management to remove all affected tissue without reseeding.

Radiographic Findings and Clinical Correlates in Pediatric Periorbital Infections.

OBJECTIVE: To review radiographic studies of pediatric patients presenting with periorbital infections and to evaluate sinonasal anatomical factors and clinical course related to this disease process. METHODS: Retrospective study review of computed tomography (CT) scans in 100 patients less than 18 years old, admitted to a tertiary children's hospital with the diagnosis of an orbital infection. CT scans were reviewed for anatomic variants and Lund-Mackay scores were calculated. An independent chart reviews of the treatment course and need for surgical intervention was performed. RESULTS: Of 100 patients, 67% were male, 60% had left-sided infections, and 30% of patients were treated with surgical drainage. Adenoid hypertrophy (61%), inferior turbinate hypertrophy (80%) and septal deviation (47%) were common, but did not show statistical correlation with the need for surgical intervention. Dehiscence of the lamina papyracea was identified in 21% of patients treated without surgery and in 76% of those requiring surgery (P 0.0048). The average overall Lund-Mackay score was 11.8 and did not correlate with the need for surgical intervention. CONCLUSIONS: To our knowledge, this is the first study to evaluate the incidence of sinonasal anatomic abnormalities in children presenting with periorbital infections. This study also demonstrated that lamina papyracea dehiscence is a common finding and is associated with higher rates of surgical intervention. Such findings may have an important role in the diagnosis, surveillance and management of sinus disease in the pediatric population.

Hypocalcemia after minimally invasive thyroidectomy.

We conducted a retrospective study to determine the incidence of postoperative hypocalcemia following minimally invasive thyroidectomy. During the 2-year study period, 74 patients-16 men and 58 women (mean age: 43.7)-underwent either total or hemithyroidectomy through a 3-cm incision. Postoperative hypocalcemia occurred in 14 of these patients (18.9%)-4 men and 10 women-all of whom underwent total rather than hemithyroidectomy. All these patients received supplementation with calcium and vitamin D for 2 weeks postoperatively in order to regain a normal calcium status, and all demonstrated normal serum calcium levels at 3 weeks. Despite their low calcium levels, none of the 14 patients exhibited any overt symptoms of hypocalcemia. We conclude that minimally invasive thyroidectomy is associated with a low rate of postoperative hypocalcemia that is comparable to the rates previously reported for standard thyroidectomy.

Indoleamine 2,3-dioxygenase and 3-hydroxykynurenine modifications are found in the neuropathology of Alzheimer's disease.

Tryptophan metabolism, through the kynurenine pathway, produces neurotoxic intermediates that are implicated in the pathogenesis of Alzheimer's disease. In particular, oxidative stress via 3-hydroxykynurenine (3-HK) and its cleaved product 3-hydroxyanthranilic acid (3-HAA) significantly damages neuronal tissue and may potentially contribute to a cycle of neurodegeneration through consequent amyloid-beta accumulation, glial activation, and up-regulation of the kynurenine pathway. To determine the role of the kynurenine pathway in eliciting and continuing oxidative stress within Alzheimer's diseased brains, we used immunocytochemical methods to show elevated levels of 3-HK modifications and the upstream, rate-limiting enzyme indoleamine 2,3-dioxygenase (IDO-1) in Alzheimer's diseased brains when compared to controls. Importantly, the association of IDO-1 with senile plaques was confirmed and, for the first time, IDO-1 was shown to be specifically localized in conjunction with neurofibrillary tangles. As senile plaques and neurofibrillary tangles are the pathological hallmarks of Alzheimer's disease, our study provides further evidence that the kynurenine pathway is involved with the destructive neurodegenerative pathway of Alzheimer's disease.

Antigen-antibody dissociation in Alzheimer disease: a novel approach to diagnosis.

With the ever-increasing population of aged individuals at risk of developing Alzheimer's disease (AD), there is an urgent need for a sensitive, specific, non-invasive, and diagnostic standard. The majority of efforts have focused on auto-antibodies against amyloid-beta (Abeta) protein, both as a potential treatment, and a reliable biomarker of AD pathology. Naturally occurring antibodies against Abeta are found in the CSF and plasma of patients with AD as well as healthy control subjects. To date, differences between diseased and control subjects have been highly variable. However, some of the antibody will be in preformed antigen-antibody complexes and the extent and nature of such complexes may provide a potential explanation for the variable results reported in human studies. Thus, measuring total amounts of antigen or antibody following unmasking is critical. Here, using a technique for dissociating antibody-antigen complexes, we found significant differences in serum antibodies to Abeta between AD and aged-matched control subjects. While the current study demonstrates the relevance of measuring total antibody, bound and unbound, against Abeta in AD, this technique may be applicable to diseases such as acquired immune deficiency syndrome and hepatitis B where determination of antigen and antibody levels are important for disease diagnosis and assessing disease progression.

The estrogen myth: potential use of gonadotropin-releasing hormone agonists for the treatment of Alzheimer's disease.

Estrogen and other sex hormones have received a great deal of attention for their speculative role in Alzheimer's disease (AD), but at present a direct connection between estrogen and the pathogenesis of AD remains elusive and somewhat contradictory. For example, on one hand there is a large body of evidence suggesting that estrogen is neuroprotective and improves cognition, and that hormone replacement therapy (HRT) at the onset of menopause reduces the risk of developing AD decades later. However, on the other hand, studies such as the Women's Health Initiative demonstrate that HRT initiated in elderly women increases the risk of dementia. While estrogen continues to be investigated, the disparity of findings involving HRT has led many researchers to examine other hormones of the hypothalamic-pituitary-gonadal axis such as luteinising hormone (LH) and follicle-stimulating hormone. In this review, we propose that LH, rather than estrogen, is the paramount player in the pathogenesis of AD. Notably, both men and women experience a 3- to 4-fold increase in LH with aging, and LH receptors are found throughout the brain following a regional pattern remarkably similar to those neuron populations affected in AD. With respect to disease, serum LH level is increased in women with AD relative to non-diseased controls, and levels of LH in the brain are also elevated in AD. Mechanistically, we propose that elevated levels of LH may be a fundamental instigator responsible for the aberrant reactivation of the cell cycle that is seen in AD. Based on these aforementioned aspects, clinical trials underway with leuprolide acetate, a gonadotropin-releasing hormone agonist that ablates serum LH levels, hold great promise as a ready means of treatment in individuals afflicted with AD.

Nanoparticle and other metal chelation therapeutics in Alzheimer disease.

Current therapies for Alzheimer disease (AD) such as the anticholinesterase inhibitors and the latest NMDA receptor inhibitor, Namenda, provide moderate symptomatic delay at various stages of disease, but do not arrest disease progression or supply meaningful remission. As such, new approaches to disease management are urgently needed. Although the etiology of AD is largely unknown, oxidative damage mediated by metals is likely a significant contributor since metals such as iron, aluminum, zinc, and copper are dysregulated and/or increased in AD brain tissue and create a pro-oxidative environment. This role of metal ion-induced free radical formation in AD makes chelation therapy an attractive means of dampening the oxidative stress burden in neurons. The chelator desferioxamine, FDA approved for iron overload, has shown some benefit in AD, but like many chelators, it has a host of adverse effects and substantial obstacles for tissue-specific targeting. Other chelators are under development and have shown various strengths and weaknesses. In this review, we propose a novel system of chelation therapy through the use of nanoparticles. Nanoparticles conjugated to chelators show a unique ability to cross the blood-brain barrier (BBB), chelate metals, and exit through the BBB with their corresponding complexed metal ions. This method may prove to be a safe and effective means of reducing the metal load in neural tissue thus staving off the harmful effects of oxidative damage and its sequelae.

Carnosine: a versatile antioxidant and antiglycating agent.

Carnosine (beta-alanyl-L-histidine) has recently attracted much attention as a naturally occurring antioxidant and transition-metal ion sequestering agent. It has also been shown to act as an anti-glycating agent, inhibiting the formation of advanced glycation end products (AGEs). Through its distinctive combination of antioxidant and antiglycating properties, carnosine is able to attenuate cellular oxidative stress and can inhibit the intracellular formation of reactive oxygen species and reactive nitrogen species. By controlling oxidative stress, suppressing glycation, and chelating metal ions, carnosine is able to reduce harmful sequelae such as DNA damage. AGEs are known contributors to the pathology of Alzheimer's disease, and carnosine therefore merits serious attention as a possible therapeutic agent.

Tau phosphorylation in Alzheimer's disease: pathogen or protector?

During the past decade, hypotheses concerning the pathogenesis of most neurodegenerative diseases have been dominated by the notion that the aggregation of specific proteins and subsequent formation of cytoplasmic and extracellular lesions represent a harbinger of neuronal dysfunction and death. As such, in Alzheimer's disease, phosphorylated tau protein, the major component of neurofibrillary tangles, is considered a central mediator of disease pathogenesis. We challenge this classic notion by proposing that tau phosphorylation represents a compensatory response mounted by neurons against oxidative stress and serves a protective function. This novel concept, which can also be applied to protein aggregates in other neurodegenerative diseases, opens a new window of knowledge with broad implications for both the understanding of mechanisms underlying disease pathophysiology and the design of new therapeutic strategies.