Triangle target principle for the placement of trocars during video-assisted thoracic surgery.

OBJECTIVE: The baseball-diamond principle is generally used for trocar placement during video-assisted thoracic surgery; however, we are unable to treat all peripheral lung lesions using this principle. Therefore, we have developed another method for determining trocar placement based on a modification of the conventional principle. We have termed this method the triangle target principle. This report describes the instrument positioning that we now use for many video-assisted thoracic surgical procedures. METHODS: We position 3 trocars in an equilateral triangle, with the target lesion at the apex. One vertex of the base becomes the site of the first trocar placement for introduction of the thoracoscopic camera. Another vertex of the base becomes the site for the second trocar for forceps or the endoscopic stapler. The third trocar is for forceps and is inserted to create the vicinity of target lesion. Four types of the triangle target principle were developed according to sites of the target lesion. RESULTS: Between January 2000 and December 2002, we used this principle for 161 patients who underwent video-assisted thoracic surgery and all intrathoracic lesions were accessible except in 3 patients requiring intraoperative modifications. CONCLUSIONS: We conclude that video-assisted thoracic surgery by this principle is more effective and easier than the conventional principle to treat intrathoracic disease.     

Inhibitory effect of calcium chloride on gastric carcinogenesis in rats after treatment with N-methyl-N'-nitro-N-nitrosoguanidine and sodium chloride.

The effects of calcium chloride on glandular stomach carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and sodium chloride were investigated in male outbred Wistar rats. Animals were given MNNG solution (100 p.p.m.) as drinking water and simultaneously fed a diet supplemented with 5% sodium chloride for 8 weeks. Matched negative controls received neither MNNG nor sodium chloride. Rats were then fed basal diet and given calcium chloride solution (1 or 0.2%) or tap water for the following 52 weeks. The incidences and multiplicities of preneoplastic hyperplasias in the glandular stomachs of rats given MNNG/sodium chloride followed by 1 and 0.2% calcium chloride were significantly lower than those in rats given MNNG/sodium chloride alone. The inhibitory effects of calcium were exerted in a dose-dependent manner. Calcium treatment also showed a tendency to inhibit the development of gastric adenocarcinomas although this was not statistically significant. Rats without carcinogen treatment had neither carcinomas nor preneoplastic hyperplasias in the glandular stomach. Calcium intake also significantly reduced the levels of malondialdehyde, a measure of lipid peroxidation, in the gastric mucosa and urine, the former in a dose-dependent manner. Thus, calcium chloride exerted inhibitory effects when given during the post-initiation phase of two-stage glandular stomach carcinogenesis in rats.     

Effects of Ageing on the Oral Absorption of d-Xylose in Rats: Analysis of Gastrointestinal Disposition

The effects of ageing on the oral (gastrointestinal) absorption of d -xylose were investigated by analysing the gastrointestinal disposition after oral administration to young (9 weeks) and old (53 weeks) rats. A linear model assuming first-order gastric emptying followed by first-order intestinal absorption was fitted to remaining fraction vs time profiles for the stomach and small intestine to estimate the gastric emptying rate constant (k_g) and the intestinal absorption rate constant (k_a). In young and old rats, k_g values were 0·087 ± 0·008 and 0·070 ± 0·007 min^?1, respectively, and k_a values were 0·020 ± 0·002 and 0·018 ± 0·002 min^?1 suggesting an insignificant effect on ageing on the rate of oral absorption. The average intestinal lumen volume (V_av) was unchanged with ageing, and so was the apparent intestinal membrane permeability clearance (CL_app) as the product of k_a and V_av. However, the small intestinal transit time (T_si) was suggested to be twice that in older rats (171 min) than in young rats (78 min) by the analysis of gastrointestinal disposition of inulin, a non-absorbable marker. It was also shown that our preceding finding of an increase in the fraction absorbed of D-xylose with ageing can be solely ascribable to the delay in intestinal transit. Thus, among various determinants of oral absorption, only T_si was found to be altered with ageing. The CL_a,app and k_a of passively absorbed drugs such as D-xylose may be generally unchanged, and the fraction absorbed may increase with ageing by the delay in intestinal transit.     

Differential mechanism of retention of Cu-pyruvaldehyde-bis(N4-methylthiosemicarbazone) (Cu-PTSM) by brain and tumor: A novel radiopharmaceutical for positron emission tomography imaging

The reductive retention of⁶²Cu-PTSM was comparatively studied in the brain and Ehrlich ascites tumor cells by electron spin resonance spectrometry and nonradioactive Cu-PTSM. In the brain, only the mitochondrial fraction showed the ability to reduce Cu-PTSM, and the other subcellular fractions did not. In contrast, the cytosolic fraction of Ehrlich ascites tumor cells was the specific site of Cu-PTSM reduction. It was therefore considered that the retention of Cu-PTSM in the brain is closely related to mitochondrial reduction, most probably involving the mitochondrial electron transport system.     

Experimental study on choline acetyltransferase activity measurement for brachial plexus injury

We studied choline acetyltransferase (CAT) activity in a rat model of brachial plexus injury. In experiment 1, we found that the CAT activity was remarkably high in the anterior roots and low in the posterior roots. In experiment 2, nerve root segments were extracted and examined for CAT activity in the root avulsion group (group A) and the plexus severance group (group B). CAT activity decreased day by day in group A, reaching about 1/20 of the normal 5 days postoperatively. By contrast, in group B activity decreased only slightly, and even at 90 days postoperatively was about 6,000 cpm (one-half normal level). As a result, CAT activity enabled us to distinghish postganglionic from preganglionic injury of the cervical roots. Furthermore, it was a useful adjunct for minimizing nerve loss in intercostal nerve transfer, distinguishing motor and sensory branches of the intercostal nerve, and evaluating the motor nerve activity. © 1995 Wiley-Liss, Inc.     

Surgical results of performing R4 gastrectomy for gastric cancer located in the upper third of the stomach

Because gastric cancers located in the upper third of the stomach are difficult to detect at an early stage, the surgical results remain poor. We performed R4 gastrectomy as a radical procedure for 25 patients, involving complete resection of the latero-aortic and interaorticovenous lymph modes above and below the left renal vein, in combination with the ordinary R2 or R3 gastrectomy (the R4 group). These patients were compared with 156 others who underwent R2 gastrectomy alone (the R2 group). There were no significant differences in operation time, blood loss, or the incidence of complications between the two groups; however, when the survival rates of the patients with tumors invading beyond the subserosa were compared, the 5-year survival rate was found to be significantly higher in the R4 group than in the R2 group. Furthermore, in patients with para-aortic nodal involvement, a significant survival advantage was observed in the R4 group, as compared with the R2 group. These results suggest that the R4 gastrectomy is a rational approach for patients with advanced gastric cancer located in the upper third of the stomach.     

Antiepileptic effects of inhibitors of nitric oxide synthase examined in pentylenetetrazol-induced seizures in rats

The effects of intraperitoneal and methyl ester, specific inhibitors of nitric oxide (NO) synthase, were examined on the pentylenetetrazol (PTZ)-induced seizures in rats. The incidence and latency for the onset of myoclonic jerks, clonic seizures, and tonic generalized extension were observed as specific parameters among PTZ-induced seizures. Both drugs preferentially suppressed the tonic generalized extension and prolonged the latency for the onset of each parameter, suggesting NO has a significant effect on the PTZ-induced seizure.     

Primary malignant melanoma of the rectum: Report of a case

We describe herein a rare case of primary malignant melanoma of the rectum in an 85-year-old woman. The patient presented with intermittent rectal bleeding, and a colonoscopy revealed an ulcerated polypoid mass in the rectum, located 5 cm from the anal verge. The lesion was histologically characterized by solid growths of small round cells with scanty cytoplasm and prominent nucleoli. Although no melanin pigment was found in the tumor cells, they were immunohistochemically positive for HMB-45, a monoclonal antibody highly specific for malignant melanoma. Thus, HMB-45 proved very useful to establish a diagnosis of amelanotic malignant melanoma of the rectum.