MR imaging of normal perivascular space expansion at midbrain

BACKGROUND AND PURPOSE: A previous investigation of the MR imaging findings in the midbrain reported expanded perivascular (PV) spaces in only the ponto-mesencepalic junction (PMJ) in 20% of healthy subjects, whereas pathologically expanding PV spaces have been reported at the mesencephalo-diencephalic junction (MDJ) as multi-lobulated, cystic lesions with signal intensity compatible with that of CSF that cause aqueductal stenosis. To clarify the anatomical distinctions between normally expanded and pathologically expanding PV spaces, we defined their distribution in the normal midbrain by using high-spatial-resolution MR imaging. METHODS: Heavily T2-weighted MR imaging was performed in 115 adult subjects with neurologic complaints without cerebral disease. Histologic studies were performed from two normal midbrain blocks. RESULTS: Expanded PV spaces were visible at the PMJ in 87% of subjects and at the MDJ in 63% of subjects. On axial images, ovoid or linear lesions with signal intensity compatible to CSF were present behind the cerebral peduncle at both the PMJ and MDJ. These areas varied from less than 1 mm to 5 mm (maximum diameter on coronal sections). Histologic studies confirmed the distribution of expanded PV spaces, as noted on MR images. CONCLUSION: This study, by using high-spatial-resolution MR imaging, revealed that expanded PV spaces were visible at the PMJ and MDJ. Our finding of expanded PV spaces normally present at the MDJ may be related to pathologically expanding PV spaces, which should be kept in mind as a differential diagnosis for intraparenchymal cystic lesions in the midbrain with signal intensity compatible to CSF.     

Pallidoreticular damage in acute carbon monoxide poisoning: diffusion-weighted MR imaging findings

We describe a case of carbon monoxide poisoning that led to pallidoreticular damage and delayed leukoencephalopathy. Serial diffusion-weighted MR imaging was performed. A restricted water diffusion pattern was demonstrated in the globus pallidus and substantia nigra in the early stage. Diffusion-weighted imaging is useful for early identification of the effects of acute carbon monoxide poisoning.     

Chiari I malformation associated with ventral compression and instability: one-stage posterior decompression and fusion with a new instrumentation technique

OBJECTIVE AND IMPORTANCE: We describe an alternative surgical technique for treatment of Chiari I malformation associated with ventral compression and instability of the region. An expansive suboccipital cranioplasty and a rigid occipitocervical fixation are performed in one stage. METHODS: The occipitocervical fixation is performed by use of metal rods fixed on the cranial side by screws inserted into the diploic layer of occipital bone and on the caudal side by screws inserted into the pedicle of the axis or in a transarticular fashion into the lateral masses of axis and atlas vertebra. A large piece of autologous bone is placed in the region between the rostral edge of cranial decompression and the axis, with the aim of achieving both expansive suboccipital cranioplasty and occipitocervical fusion. RESULTS: We performed this procedure in two patients with Chiari I malformation associated with basilar invagination and occipitalization of the atlas. Postoperatively, decompression of the brainstem and restoration of normal cerebrospinal fluid flow at the craniovertebral junction were confirmed radiologically, and the patients were relieved of their symptoms. At 1 and 3 years of follow-up, respectively, solid bone fusion was observed between the occipital bone and axis in both patients. CONCLUSION: Simultaneous posterior decompression and occipitocervical fixation with an alternative instrumentation technique is discussed. The procedure can be performed regardless of the size of suboccipital craniectomy. Screw insertion into the diploic layer of the occipital bone has not been described previously.     

A quantitative anatomic characterization of the quadrilateral surface for periacetabular osteotomy

The periacetabular osteotomy described by Ganz et al is used widely, and includes an outward osteotomy from the quadrilateral surface. Because intraarticular extension of the osteotomy can complicate the Ganz osteotomy, it is important to image the margin of the hip. To prevent this complication, and to do this procedure more safely, 32 hemipelves from cadavers were used in the current study. Some landmarks were selected that can be clarified on the quadrilateral surface during the periacetabular osteotomy. The acetabulum was hollowed out using an acetabular reamer of the same size as each femoral head, and the margin of the penetrated hole through the acetabulum was determined using these landmarks. The posterior margin of the hip is located approximately 2 cm anterior to the sciatic notch. The anatomic guidepoint for the osteotomy of the ischium averaged 14 mm inferior to the distal margin of the hip. By clarifying the margin of the hip presumed on the quadrilateral surface in this way, the periacetabular osteotomy can be done more safely, without causing complications such as intraarticular chisel penetration.     

A comparison between calcium channel blocking drugs with different potencies for T- and L-type channels in preventing atrial electrical remodeling

Calcium overload plays a key role in the development of atrial electrical remodeling. The effect of an L-type Ca channel blocker in preventing this remodeling has been reported to be short lasting, partly due to down-regulation of this channel and persisting Ca entry through the T-type Ca channel. To prove if efonidipine, a dual L- and T-type Ca channel blocker exerts a greater effect than an L-type Ca channel blocker verapamil, 21 dogs underwent rapid atrial pacing at 400 bpm for 14 days, pretreatment with efonidipine in 7 (E), verapamil in 7 (V), and none in 7 (C). We measured the atrial effective refractory period (ERP) serially during 14 days of rapid pacing. In response to rapid pacing, ERP decreased progressively in C. In contrast, in E and V, ERP remained greater than ERP in C (P < 0.01) on days 2 through 7. However, on the 14th day, ERP in V decreased to the level seen in C, whereas ERP in E remained significantly longer than ERPs in C or V (P < 0.01). The blockade L-type Ca channel alone is not sufficient, but the addition of a T-type Ca channel blockade shows a more sustained effect to prevent atrial electrical remodeling.     

Cancer mortality among Japanese immigrants and their descendants in the state of São Paulo, Brazil, 1999-2001

BACKGROUND: Only a few studies on the mortality of Japanese immigrants have been conducted in Brazil despite a large population of Japanese immigrants and their different environment and lifestyle from Japanese living in Japan. METHODS: To compare cancer mortality between Japanese in Japan and Japanese immigrants or Brazilians in the state of S?o Paulo, Brazil, we obtained official death certificates registered during 1999-2001. The standardized mortality ratio (SMR) or the standardized proportional mortality ratio (SPMR) of major cancer sites was calculated for the first generation of Japanese immigrants to Brazil (Japan-born), their Brazil-born Japanese descendants, and native Brazilians using mortality data of Japanese in Japan as a standard. RESULTS: The SMRs of stomach and colorectal cancer did not differ between the Japan-born residents of Brazil and the native Japanese, but significantly low SMRs were found among the native Brazilians. Compared with the native Japanese, we observed significantly lower SMRs for liver, gallbladder and lung cancer and significantly higher SMRs for prostate, cervical, and brain and nervous system cancer among both the Japan-born residents of Brazil and the Brazilians. Generally, the SPMR results were similar to those of the SMRs. Significantly high SPMRs for breast and uterine cancer were found for both the Japan- and Brazil-born residents of Brazil, although the Japan-born residents had increased SMRs, but not significantly so. CONCLUSIONS: We confirmed the different cancer mortality pattern in the Japanese immigrants from that in Japanese in Japan, thus demonstrating the relative importance of the environment in the development of cancer.     

Evaluation of multimodality therapy for synchronous liver metastases of gastric cancer

We evaluated the significance of multimodality therapy for cases of liver metastases of gastric cancer. Accumulated survival rate and median survival time were analyzed for twenty cases of such gastric cancer. Survival rates of H1+H2 group and hepatic resection (HR) group were higher than that of H3 group and non-HR group. MST of HR group and hepatic arterial infusion (HAI) group were longer than that of non-HR group and non-HAI group. Survival rate of HAI group was higher than that of non-HAI group among eleven cases of HR group. On the other hand, survival rate of HR group was higher than that of non-HR group among eleven cases of HAI group. These results suggested that HAI chemotherapy after hepatic resection for gastric cancer patients with synchronous liver metastasis would improve prognosis.     

Airway management during the laryngoscopic surgery for the benign laryngeal obstructive disease

The airway management and anesthesia maintenance during the laryngoscopic surgery is essential for a safe operation. For the benign laryngeal obstructive disease such as a large mass or a foreign body of the upper airway, it is difficult to secure the airway. Sometimes they might be hazardous and potentially lethal. We present two cases of a large laryngeal polyp and a laryngeal foreign body of pressthrough-package (PTP). They were successfully operated on with laryngomicrosurgery under neuroleptanalgesia (NLA) without intubation. The choice of the operation and airway management were discussed.     

Effect of various anti-glaucoma eyedrops on human corneal epithelial cells

PURPOSE: To investigate the effects of antiglaucoma eyedrops and vehicles on the proliferation of human corneal epithelial cells. MATERIAL AND METHODS: Seven eyedrops[prostaglandin F2 alpha analogs(2), beta blockers(40), topical carbonic anhydrase inhibitor(1)], and six of the eyedrop vehicles, excluding that of Xalatan, were used. Anti-glaucoma eyedrops and vehicles were serially diluted 2-fold with culture medium(10-2,560 fold). The mixture was added to human corneal epithelial cells and incubated for 48 hrs. Cell proliferation was measured by commercial assay kit. Dye-reagents were added to the wells and incubated for 1 h at 37 degrees C. Optical density were measured at 490 nm. The dilution rate for 50% inhibition was calculated as the dilution rate of drugs or vehicles necessary to produce 50% inhibition of cell proliferation. RESULT: All drugs completely inhibited cell proliferation when the dilution rate was low. At 40-fold dilution, Trusopt and Timoptol showed a significant decrease in cell growth inhibition. On the other hand, Rescula showed almost 100% inhibition at 160-fold dilution. Above 640-fold dilution, the inhibition rate of all drugs became 50% or less and there was no significant difference between drugs. Vehicles also inhibited cell growth. The dilution rates for growth inhibition by vehicles were different from those of drugs. The dilution rate at 50% inhibition of anti-glaucoma eyedrops decreased in the following order: Rescula > Xalatan > Betoptic > Hypadil > Mikelan > Timoptol > Trusopt. The dilution rate for 50% inhibition of vehicles decreased in the following order: Rescula vehicle > Hypadil vehicle > Betoptic vehicle > Mikelan vehicle > Timoptol vehicle > Trusopt vehicle. CONCLUSION: All anti-glaucoma eyedrops inhibited cell proliferation. These effects were stronger in prostaglandin F2 alpha analogs and weakest in Trusopt. Furthermore, the inhibition of cell proliferation was caused also by the vehicle of eyedrops, and the influence of the vehicle varied in each type of eyedrops.