CO2 reactivity and autoregulation in fetal brain

Intraventricular hemorrhage (IVH) in preterm infants is well known to be associated with the high morbidity and mortality of this group. Previous studies have suggested altered cerebral blood flow (CBF) as an important pathologic factor. We measured the CBF in nearterm rabbit fetuses using the hydrogen clearance technique. The local CBF of the rabbit fetuses was significantly low compared with that of the maternal rabbits. The response of CBF to changes in PaCO₂ was observed in rabbit fetuses. The CO₂ reactivity index of the fetal rabbit was lower than that of the maternal rabbit. This low CO₂ reactivity might reflect the immaturity of the fetal brain and its low CBF. We were unable to monitor the fetal blood pressure, but the fetal CBF remained stable when the maternal blood pressure was altered. It is well known that IVH in preterm infants originates from the subependymal germinal matrix and that this has many fragile vessels. Our observation suggests that even a small increase of CBF during hypercapnia might have a large effect towards producing hemorrhage.     

Novel antifungal antibiotics maniwamycins A and B. I. Taxonomy of the producing organism, fermentation, isolation, physico-chemical properties and biological properties

Two antifungal antibiotics maniwamycins A and B were isolated from the culture broth of a strain of actinomycetes, which were classified as Streptomyces prasinopilosus. These antibiotics were isolated by resin absorption and extraction with EtOAc and purified by column chromatography. Both antibiotics were found to be new azoxy substances from their physico-chemical properties. They showed broad antifungal spectra.     

Purification and characterization of aplysianin E, an antitumor factor from sea hare eggs

An antitumor factor, aplysianin E, inducing tumor lysis was purified to apparent homogeneity from the supernatant of a homogenate of eggs of the sea hare Aplysia kurodai. Purified aplysianin E was a 250-kDa glycoprotein containing three different subunits. This factor was half-maximally active at 2-114 ng protein/ml and lysed all the tumor cells tested but did not lyse normal white or red blood cells. Aplysianin E was labile on treatments with heat, low pH, urea, guanidine, sodium lauryl sulfate, and periodate, but not with proteases or organic solvents, Aplysianin E completely inhibited the syntheses of DNA, RNA, and protein by tumor cells within 2 h and caused their complete cytolysis within 15 h. Tumor lysis by aplysianin E was inhibited by N-acetylneuraminic acid, suggesting that recognition of the sugar moiety is a key step in cytolysis induced by aplysianin E. Aplysianin E also prolonged the survival of mice bearing syngeneic MM46 ascites or solid tumors. These results suggest that aplysianin E, found in an invertebrate, the sea hare, is a new antitumor factor.     

Clinical outcome of surgical management for patients with renal cell carcinoma involving the inferior vena cava

BACKGROUND: The objective of this study was to evaluate the clinical outcome after surgical management of renal cell carcinoma (RCC) extending to the inferior vena cava (IVC). METHODS: This study included a total of 55 patients (41 men and 14 women; mean age, 59.3 years) with RCC (39 right- and 16 left-sided tumors) involving the IVC, who underwent radical nephrectomy and tumor thrombectomy between 1983 and 2005 at a single institution in Japan. The level of thrombus was classified as follows: level I, infrahepatic; level II, intrahepatic; level III, suprahepatic; and level IV, extending to the atrium. Clinicopathological data from these patients were retrospectively reviewed to identify factors associated with survival. RESULTS: There were 11 and 18 patients who were diagnosed as having lymph node and distant metastases, respectively. Twenty-two patients had tumor thrombus in level I, 20 in level II, 10 in level III, and 3 in level IV. Pathological examinations demonstrated that 34 and 21 patients had clear cell carcinoma and non-clear cell carcinoma, respectively, 42, 9 and 4 were pT3b, pT3c and pT4, respectively, and 6, 35 and 14 were Grades 1, 2 and 3, respectively. Cancer-specific 1-, 3- and 5-year survival rates of these 55 patients were 74.5%, 51.4% and 30.3%, respectively. Among several factors examined, clinical stage (P = 0.047), lymph node metastasis (P = 0.016), histological subtype (P = 0.034) and tumor grade (P < 0.001) were significantly associated with cancer-specific survival by univariate analysis. Furthermore, multivariate analysis demonstrated clinical stage (P = 0.037) and tumor grade (P < 0.001) as independent predictors of cancer-specific survival irrespective of other significant factors identified by univariate analysis. CONCLUSIONS: In patients with RCC involving the IVC, biological aggressiveness characterized by tumor grade rather than tumor extension would have more potential prognostic importance; therefore, more intensive multimodal therapy should be considered in patients with high grade RCC with tumor thrombus extending into the IVC.     

Resetting of the arterial baroreflex increases orthostatic sympathetic activation and prevents postural hypotension in rabbits

Since humans are under ceaseless orthostatic stress, the mechanism to maintain arterial pressure (AP) under orthostatic stress against gravitational fluid shift is of great importance. We hypothesized that (1) orthostatic stress resets the arterial baroreflex control of sympathetic nerve activity (SNA) to a higher SNA, and (2) resetting of the arterial baroreflex contributes to preventing postural hypotension. Renal SNA and AP were recorded in eight anaesthetized, vagotomized and aortic-denervated rabbits. Isolated intracarotid sinus pressure (CSP) was increased stepwise from 40 to 160 mmHg with increments of 20 mmHg (60 s for each CSP level) while the animal was placed supine and at 60 deg upright tilt. Upright tilt shifted the CSP–SNA relationship (the baroreflex neural arc) to a higher SNA, shifted the SNA–AP relationship (the baroreflex peripheral arc) to a lower AP, and consequently moved the operating point to marked high SNA while maintaining AP. A simulation study suggests that resetting in the neural arc would double the orthostatic activation of SNA and increase the operating AP in upright tilt by 10 mmHg, compared with the absence of resetting. In addition, upright tilt did not change the CSP–AP relationship (the baroreflex total arc). A simulation study suggests that although a downward shift of the peripheral arc could shift the total arc downward, resetting in the neural arc would compensate this fall and prevent the total arc from shifting downward to a lower AP. In conclusion, upright tilt increases SNA by resetting the baroreflex neural arc. This resetting may compensate for the reduced pressor responses to SNA in the peripheral cardiovascular system and contribute to preventing postural hypotension.     

Clinical significance of selective middle hepatic venography

Selective middle hepatic venography was performed in 86 patients who had been scheduled to undergo liver resection because of hepatobiliary diseases. Special catheters were used of which tips were bended counterclockwise at an angle of 45 degrees. Successful middle hepatic venograms were obtained in 65 cases (76%). Abnormal findings were observed in 27 cases (42%), and it was difficult to diagnose them by ultrasonography or computed tomography. Selective middle hepatic venogram is very useful to understand surgical anatomy of the liver in each case preoperatively. In 5 cases of giant tumor, middle hepatic venography is necessary to identify the exact site of the tumor. Selective middle hepatic venography is considered to be one of the indispensable, examinations for liver resection.