Megumi Fujikawa

Effect of aging on regulation of brain stem circulation during hypotension.

This study was designed to determine age-related changes in autoregulatory responses of the brain stem circulation in vivo. In anesthetized adult (4 to 6 months, n = 8) and aged (24 to 26 months, n = 7) Sprague-Dawley rats, local CBF to the brain stem was determined with laser-Doppler flowmetry and diameters of the basilar artery and its branches were measured through an open cranial window during stepwise hemorrhagic hypotension. In aged rats, the lower limit of CBF auto-regulation shifted upward to 60 to 75 mm Hg from 30 to 45 mm Hg in adult rats. Dilator responses of the basilar artery (baseline diameter: 254 ± 15 μm), large branch (109 ± 23 μm), and small branch (44 ± 10 μm) to hypotension were much smaller in aged rats than in adult rats. The maximum change in diameter of the basilar artery during profound hypotension was significantly smaller in aged rats (11 ± 8%) than that in adult ones (23 ± 12%, P < 0.05); that of the large branch was 12 ± 8% versus 33 ± 17% (P < 0.005); and that of the small branch was 17 ± 7% versus 40 ± 13% (P < 0.0005), suggesting greater attenuation of the responses in the smaller vessels. Thus, this study provides direct evidence that aging diminishes the compensatory dilatation of brain stem arterioles and arteries during hypotension and modifies the autoregulatory plateau of CBF, which seems to increase the risk of the brain stem ischemia during hypotensive conditions.

Reversible primary hypothyroidism with blocking or stimulating type TSH binding inhibitor immunoglobulin following recombinant interferon‐α therapy in patients with pre‐existing thyroid disorders

OBJECTIVE Treatment with recombinant interferon‐α (rIFN‐α) may induce autoimmunity. We have evaluated the effect of rIFN‐α on pre‐existing thyroid disease with special reference to changes in TSH receptor antibody.

Age-Related Changes in Response of Brain Stem Vessels to Opening of ATP-Sensitive Potassium Channels

BACKGROUND AND PURPOSE This study was designed to determine regional differences and age-related changes in the contribution of ATP-sensitive potassium (KATP) channels to vasodilator responses in the brain stem circulation in vivo. METHODS Changes in diameter of the basilar artery (baseline diameter, 270 +/- 5 microns [mean +/- SEM]), its large branch (112 +/- 5 microns), and its small branch (49 +/- 2 microns) in response to KATP channel openers levcromakalim and Y-26763 were measured through a cranial window in anesthetized adult (4 to 6 months) and aged (24 to 26 months) Sprague-Dawley rats. RESULTS Topical application of levcromakalim and Y-26763 produced concentration-dependent vasodilation that was similar among the three vessel groups in adult rats. In aged rats, dilator responses of the branches, but not of the basilar artery, to the KATP channel openers were smaller than those in adult rats (P < .05). Glibenclamide, a selective KATP channel blocker, almost abolished this vasodilation in both groups of rats. Vasodilator responses to sodium nitroprusside were preserved in aged rats. CONCLUSIONS In adult rats, there is no regional heterogeneity in vasodilator response to KATP channel openers in the brain stem circulation in vivo. In aged rats, although KATP channels are also functional in the brain stem circulation, dilator response of the microvessels but not of the large arteries to direct activation of KATP channels is impaired.

Elevated bone resorption markers in a patient with hypercalcemia associated with post-partum thyrotoxicosis and hypoadrenocorticism due to pituitary failure

A 36-yr-old woman began to suffer from headache, anorexia and general fatigue at 35 weeks’ gestation. About 2 or 3 months after the delivery, fever, tachycardia and generalized musculoskeletal disorder appeared. Thereafter, they worsened rapidly, accompanied by a disturbance of consciousness and hypercalcemia. Thyrotoxicosis, due to a post-partum thyroiditis, and glucocorticoid deficiency, due to a pituitary failure, probably associated with lymphocytic hypophysitis, were also observed. All the symptoms and hypercalcemia disappeared after the glucocorticoid replacement therapy and the normalization of thyroid hormone levels. Serum and urinary bone resorption markers, such as urine pyridinoline (U-Pyr), urine deoxypyridinoline (U-DPD), urine amino-terminal telopeptide of type I collagen (U-NTx) and serum carboxyterminal telopeptide of type I collagen (ICTP), were extremely high at the hypercalcemic state. In this case, they were 10 to 20 times higher than the normal upper limits, and then markedly decreased in a normocalcemic state, thereby showing an extreme acceleration of bone resorption in a state of both thyrotoxicosis and glucocorticoid deficiency.

Hypercalcemia associated with parathyroid hormone–related protein at the terminal stage of uncomplicated squamous cell carcinoma in the head and neck region

Parathyroid hormone–related protein (PTHrP) is mainly responsible for hypercalcemia in squamous cell carcinomas (SCCs).

Hepatitis G virus infection in a high-risk subgroup of hospitalized dental patients

OBJECTIVE The prevalence of hepatitis G virus infection was evaluated in dental patients whose clinical laboratory test results were positive for hepatitis C virus antibody, hepatitis B virus surface antigen, or elevated serum alanine transaminase concentrations. STUDY DESIGN Frozen serum samples from patients with hepatitis C virus antibody (n = 63), hepatitis B virus surface antigen (n = 20), or alanine transaminase concentrations greater than 100 IU (n = 14) were assessed for GB virus C (GBV-C)/hepatitis G virus RNA by a reverse transcriptase-polymerase chain reaction. RESULTS Six of 63 patients with hepatitis C virus antibodies had serum hepatitis G virus RNA (9.5%), and 2 of 20 subjects with hepatitis B virus surface antigen had hepatitis G virus RNA (10.0%). None of 14 patients whose alanine transaminase concentration was greater than 100 IU/L had hepatitis G virus RNA. Of 4 subjects with both hepatitis C virus antibody and hepatitis B virus surface antigen, 2 had hepatitis G virus RNA (50%). In the total study population (N = 92), 6 subjects (6.5%) had hepatitis G virus RNA. All hepatitis G virus-infected patients also had hepatitis C virus antibody. Neither serum alanine transaminase nor aspartate transaminase concentrations were different between subjects with and subjects without hepatitis G virus RNA. The lack of a relationship between hepatitis G virus infection and elevation of alanine transaminase and aspartate transaminase might suggest that this virus is not truly a hepatitis virus. CONCLUSIONS Hospitalized dental patients are infected with hepatitis G virus at a prevalence similar to or slightly higher than that seen in the general population. Dentists should pay close attention to infection control with respect to the potential new hepatitis virus known as hepatitis G virus.

Multiple intracranial recurrent tumors with hyperprolactinemia combined with a parasellar malignant fibrous histiocytoma long after transfrontal surgery and irradiation to a pituitary adenoma

We herein describe a 40-year-old woman with hyperprolactinemia, an empty sella and two extrasellar intracranial recurrent tumors which were revealed 23 years after the first transfrontal craniotomy and 18 years after the second transfrontal surgery and irradiation to a provable prolactin-producing pituitary macroadenoma. One recurrent tumor was in the right orbital apex causing right oculomotor nerve palsy, and the other tumor was in the right apex partispetrosae and foramen jugulare. Although her serum prolactin level decreased after the administration of bromocriptine mesilate, and the size of the two tumors remained unchanged, a malignant fibrous histiocytoma, which might have been induced by the irradiation 18 years before, grew rapidly in the right suprasellar-prepontine cistern to the right pedunculus cerebralis, leading to a poor prognosis. This case confirmed the importance of the life-lasting follow-up of pituitary adenomas treated with surgery and/or irradiation therapy. Not only ectopic recurrence of the primary tumor but also post-irradiation tumors may become apparent long after the removal of the primary tumor.

Increased sensitivity to thyroid hormone replacement therapy followed by hyponatremia and eosinophilia in a patient with long-standing young-onset primary hypothyroidism

We describe a 51-year-old woman with long-standing young-onset primary hypothyroidism. Serum cortisol, adrenocorticotropin, and arginine vasopressin levels were normal, but urinary excretion of 17-hydroxycorticosteroid was decreased. Administration of a very small initial dose of thyroid hormone induced severe acute complications including fever, palpitation, and sweating associated with a rapid decrease in serum thyrotropin level, a dramatic increase in serum alkaline-phosphatase level, and a decrease in serum total cholesterol level. A week later, the late complications of nausea, severe hyponatremia, and eosinophilia occurred. Serum cortisol level decreased slightly but remained within normal limits during this hyponatremic period. This rare case suggests that increased sensitivity to thyroid hormone can occur in long-standing primary hypothyroidism with biphasic clinical course of acute thyrotoxic complications followed by severe hyponatremia resembling hypoadrenocorticism.