Idiopathic hypertrophic cranial pachymeningitis: clinicoradiological spectrum and therapeutic options.

OBJECTIVE: Idiopathic hypertrophic cranial pachymeningitis is a rare disease, of undetermined pathogenesis, that is characterized by inflammation and fibrosis of the dura mater. METHODS: We encountered six patients with idiopathic hypertrophic cranial pachymeningitis and analyzed their clinical presentations, radiological findings, and treatment. RESULTS: In the six patients, the main manifestations were cranial nerve palsies and headache. Three associations were present, namely optic neuropathy, Tolosa-Hunt syndrome, and diabetes insipidus. Gadolinium-enhanced magnetic resonance imaging was diagnostic, showing intense dural enhancement in a linear or nodular pattern. The responses to corticosteroid therapy were better for patients who exhibited linear, rather than nodular, dural enhancement. For one patient, surgical decompression of the superior orbital fissure provided lasting relief. The course of the disease followed one of three patterns, i.e., sustained remission, relapse with corticosteroid independence, or relapse with corticosteroid dependence. Pulse corticosteroid therapy provided significant relief, while reducing the daily corticosteroid requirement and avoiding side effects, for a corticosteroid-dependent relapsing patient. CONCLUSION: Idiopathic hypertrophic cranial pachymeningitis exhibits varied clinical courses. It is important to prevent irreversible cranial neuropathy during the active phase of the disease, using daily administration of corticosteroids, pulse corticosteroid therapy, or surgical decompression.

An antimutagenic metabolite, streptovaricin C, isolated from Streptomyces sp.

Streptomyces sp. KM1-30 was isolated from soil as a producer of antimutagens by screening with a modified Ames test. The chemical structure of the antimutagenic metabolite was identified as streptovaricin C, which is known to inhibit DNA dependent RNA polymerase from E. coli and RNA dependent DNA polymerase from RNA tumor viruses, by MS and 1H-, 13C-NMR analyses. Addition of streptovaricin C to the cultures of UV treated Salmonella typhimurium TA100 or Trp-P-2-treated S. typhimurium TA98 decreased the frequency of mutation without a decrease in viable cell counts. The effect of streptovaricin C to the mutation induced by UV and Trp-P-2 was not desmutagenic, but antimutagenic.

Titanium aneurysm clips: mechanical characteristics and clinical trial.

Titanium clip is well documented to reduce the artifact observed in computed tomography (CT) or magnetic resonance (MR) imaging and improve the quality of these images. There are, however, some demerits based on metallic characteristics including large spring portions, lack of long and fenestration clips, and difficulties to produce. We examined the mechanical characteristics of Sugita titanium aneurysm clips (product of 6 aluminium-4 vanadium-titanium) and investigate the safety in clinical use and the imaging quality compared with those of cobalt (Co) alloy clips. On mechanical test, Sugita titanium clips showed no significant difference in closing force compared with the conventional Co alloy clips. The closing force reduced about 10% after 100 times repeated opening in titanium clips in contrast with no remarkable changes in Co alloy clips. Sixty-four patients with ruptured or unruptured cerebral aneurysms (total number of 71 aneurysms) were treated with Sugita titanium clips through the microsurgical technique. None of the unfavorable outcome occurred in related to the titanium clips. Neither clip dislocation nor deformation was experienced in this series during the follow-up period. The clip artifacts seen in CT and MR image were markedly reduced, however, MR angiography had less quality to resolve anatomical structures due to an existence of vessel gap. These results indicate that in spite of some disadvantages, Sugita titanium clips allow safe and beneficial use routinely in aneurysm surgery insofar as the complete clipping is obtained.

A comparative study of intracranial aneurysm clips: closing and opening forces and physical endurance.

OBJECTIVE: The closing and opening forces of various types of intracranial aneurysm clips were measured, and the physical endurance of the clips was evaluated. METHODS: Straight, bayonet, angled, fenestrated, and temporary Sugita and Yasargil clips were tested by measuring the forces exerted by the blades as they were opened in wider increments and at various points along their length by a specially designed clip tester. Closing forces after repeated openings, continuous opening, or multiple sterilization procedures also were measured. RESULTS: The opening forces of Yasargil clips increased linearly and more sharply as the blades were opened wider than those of Sugita clips. Only Sugita clips showed significant differences between the opening and closing forces (hysteresis). Closing forces of all of the tested clips were according to a hyperbolic curve. Straight clips showed a sharper rise in closing forces than those of bayonet, angled, or fenestrated clips. A relatively weak closing force at the tip of Yasargil long clips and a strong closing force at the base of temporary clips were unexpected findings. The closing force decreased by only 3 to 7% after 500 openings and did not decrease after continuous opening for 17 hours or 100 sterilization procedures. CONCLUSION: Our study showed that the closing forces differed depending not only on the distance of the point of measurement from the clip spring but also on the shapes of the clip blades. Repeated opening or sterilization of the clips did not significantly decrease the closing forces of the aneurysm clips.

Motion and image artifacts of various intracranial aneurysm clips in a magnetic field.

Deflection angles of 36 types of Sugita intracranial aneurysm clips (Elgiloy), 2 types of Yasargil clips (Phynox), a Kirschner chip (SUS316) and a silver clip were examined by suspending each in a 1.5-tesla MRI (TOSHIBA MRT-200/FXII). Image artifacts of 5 types of intracranial aneurysm clips were also studied quantitatively with respect to their ratio of artifact/actual clip size using a spin-echo sequence with T1-weighted (Time of repetition (TR) = 500 ms, Time of echo (TE) = 20 ms) and T2-weighted (TR = 2000 ms, TE = 80 ms) images. All the Sugita clips from mini type to long type showed a deflection angle of less than 1.0 degree, the Yasargil clips less than 2.0 degrees, the Kirschner chip less than 6.0 degrees, and the silver chip did not move at all. Both brands of clips are therefore suitable for intracranial applications. The artifact size was directly proportional to the clip size and weight, though the ratio of artifact/actual width tended to decrease proportionately as the actual size and weight increased. The ratio of the width seemed slightly bigger than that of the length, but the difference did not reach statistical significance. There was no significant difference in the ratio of image artifacts/clip size between T1- and T2-weighted images.

Cavernous malformations of the optic chiasma.

Two cases of cavernous malformation of the optic chiasm are reported, and 12 previously reported cases are reviewed. The first patient presented with gradually progressive and the second patient with a subacute chiasmal syndrome. Total excision was performed in both cases. Visual function improved slightly after surgery in the first patient while the other showed marked improvement. Although cavernous malformations are angiographically occult, pre-operative diagnosis has become possible based on the characteristic features such as repeated haemorrhages in multiple sinusoidal structures as revealed by magnetic resonance imaging (MRI). A gliotic interspace between the malformation and normal neural tissue provides a plane of cleavage for dissection which permits total excision without causing new deficits. Review of previously reported cases revealed that chiasmal cavernous malformations haemorrhage more frequently than those in the brain. Early diagnosis with total excision is the treatment of choice for cavernous malformations of the optic chiasma.