Surgical Management for Systolic Anterior Motion (SAM) of the Mitral Valve in Obstructive Hypertrophic Myopathy

In patients with obstructive hypertrophic cardiomyopathy, left ventricular outflow tract (LVOT) obstruction can be created by the hypertrophic interventricular septum (IVS) as well as systolic anterior motion (SAM) of the anterior mitral leaflet (AML). Sufficient septal myectomy is a fundamental surgical technique to treat LVOT obstruction, however, direct surgical management for SAM is another key aspect. Besides the hypertrophic IVS, mitral valve, subvalvular apparatus, and papillary muscle may play important role for SAM and several surgical techniques have been proposed to treat SAM in literature. In this review, each surgical technique is classified by the anatomical structure on which the surgical procedure is applied. The AML is the main surgical site and is applied with plication (vertical plication, resection–plication–release strategy), extension (the AML extension, transverse incision of the AML), sutured (edge-to-edge repair, anterior leaflet retention plasty), or traction (floating stitch, papillary muscle-to-anterior annulus stitches, paradoxical stitches, transposition of a directed chorda tendinea to the AML). Height reduction of the posterior mitral valve leaflet and papillary muscle reorientation are other techniques. We should understand theoretical aspects of each technique on correction of anatomical and functional abnormalities of the structure and should apply them under proper indication.     

An adult case of malignant choroid plexus papilloma in the lateral ventricle and the cerebellopontine angle revealed simultaneously

An adult case of malignant choroid plexus papilloma is very rare. This report is an adult case of malignant choroid plexus papilloma revealed in the lateral ventricle and in the cerebellopontine (CP) angle simultaneously. A 37-year-old man was admitted to the hospital complaining of headache, nausea, and a floating sensation on August 29, 1984. Neurological examination on admission revealed bilateral papilledema, left dysmetria and horizontal nystagmus. CT scan revealed a slightly high density round mass in the right lateral ventricle and a cystic mass with mural nodule in the left CP angle. The intraventricular mass and mural nodule were enhanced moderately and homogeneously. The initial surgery was for removal of the CP angle tumor, and 8 days later removal of the lateral ventricle tumor was carried out. The histology of these tumors was the same and revealed malignant choroid plexus papilloma. Postoperative radiation therapy was carried out 70Gy to the brain (whole brain; 50Gy, focal; 20Gy) and 30Gy to the whole spine. About 2 years later paraparesis, lower cranial nerve palsy, and disturbance of consciousness had progressed gradually. He died of the severe recurrence of the tumor in the brain stem, and multiple dissemination in the spinal cord on September 6, 1987. There was no recurrence of tumor in the right lateral ventricle. This is a very rare case of malignant choroid plexus papilloma which was revealed in both the supra- and infratentorial regions simultaneously. They may have developed independently or they may have arisen through subarachnoid seeding. Radical removal of the tumor is important to prevent recurrence of malignant choroid plexus papilloma.     

Sodium bicarbonate infusion test: a new method for evaluating parathyroid function

We have developed a new test for estimating the secretory capacity of parathyroid hormone (PTH) from the parathyroid gland. Sodium bicarbonate solution [8.4% (w/v); 35 ml/m(2) body surface area] was infused for 2 min, and blood samples for the determination of plasma ionized calcium, plasma PTH (intact, midregion, carboxy-terminus) and related parameters were serially obtained. In 8 healthy volunteers, the mean (+/-SE) plasma ionized calcium fell promptly and significantly (from 1.21 +/- 0.01 to 1.11 +/- 0.01 mmol/L) after the sodium bicarbonate infusion. The mean (+/-SE) plasma intact PTH increased promptly and significantly, by more than four fold (42.3 +/- 4.2 to 182.4 +/- 34.7 pg/ml), and then gradually returned to basal levels. In patients with partial hypoparathyroidism who have detectable basal plasma levels of PTH, the absolute increment in PTH levels was much less, and in the plasma obtained from patients with complete hypoparathyroidism, absolutely no response was observed. Plasma obtained from patients diagnosed with primary hyperparathyroidism (parathyroid adenoma or hyperplasia) has high basal PTH levels. The response to the sodium bicarbonate infusion in these patients was markedly blunted (less than a two-fold increase in all cases examined). No significant adverse effects were observed during the procedure. Therefore, the sodium bicarbonate infusion test is a simple and sensitive method to stimulate PTH release, and is clinically useful for evaluating parathyroid gland function.     

Identification of amino acid residues responsible for von Willebrand factor binding to sulfatide by charged-to-alanine-scanning mutagenesis

von Willebrand factor (VWF) performs its hemostatic functions through binding to various proteins. The A1 domain of VWF contains binding sites of not only physiologically important ligands, but also exogenous modulators that induce VWF-platelet aggregation. Sulfatides, 3-sulfated galactosyl ceramides, that are expressed on oligodendrocytes, renal tubular cells, certain tumor cells and platelets, have been suggested to interact with VWF under some pathological conditions. The binding of VWF to sulfatide requires the A1 domain, but its binding sites have not been precisely identified. Here, we report that alanine mutations at Arg1392, Arg1395, Arg1399 and Lys1423 led to decreased VWF–sulfatide binding. These sites have been reported to be the binding sites for platelet membrane glycoprotein (GP) Ib and/or snake venom botrocetin, and, interestingly, are identical to the monoclonal antibody (mAb) NMC4 epitope previously reported to inhibit the VWF-GPIb interaction. We observed that NMC4 also inhibited VWF interaction with sulfatides in a dose-dependent manner. Thus, we conclude that VWF binding sites of sulfatide overlap those of platelet GPIb and botrocetin.