Optimal perfusion flow rate for the brain during deep hypothermic cardiopulmonary bypass at 20 degrees C. An experimental study

The relationship between the perfusion flow rate and cerebral oxygen consumption during deep hypothermic cardiopulmonary bypass at 20 degrees C was investigated in dogs. In 10 dogs the perfusion flow rate was decreased in steps from 100 to 60, 30, and 15 ml/kg/min every 30 minutes. Although cerebral blood flow decreased as perfusion flow rate decreased, the ratio of cerebral blood flow to the perfusion flow rate increased significantly (p less than 0.05) at a perfusion flow rate of 15 ml/kg/min compared to that at a perfusion flow rate of 100 or 60 ml/kg/min. The arterial-sagittal sinus blood oxygen content difference increased as perfusion flow rate decreased. Consequently, cerebral oxygen consumption did not vary significantly at perfusion flow rates of 100 (0.48 +/- 0.10), 60 (0.43 +/- 0.14), and 30 ml/kg/min (0.44 +/- 0.12 ml/100 gm/min), and it decreased significantly to 0.31 +/- 0.22 ml/100 gm/min at a perfusion flow rate of 15 ml/kg/min. In five dogs the perfusion flow rate was decreased in one step from 100 to 15 ml/kg/min, and after 60 minutes' perfusion at a perfusion flow rate of 15 ml/kg/min, the perfusion flow rate was returned to 100 ml/kg/min. Cerebral oxygen consumption decreased significantly during 60 minutes' perfusion at a perfusion flow rate of 15 ml/kg/min and did not return to its initial value after the perfusion flow rate was returned to 100 ml/kg/min. These data indicate that the optimal perfusion flow rate for the brain during deep hypothermic cardiopulmonary bypass at 20 degrees C appears to be 30 ml/kg/min, with a possible oxygen debt in the brain resulting in anaerobic metabolism if the perfusion flow rate is kept at 15 ml/kg/min or less.     

Effect of dietary fiber on cytochrome P450IA1 induction in rat colonic mucosa.

The effect of dietary fiber on the induction of cytochrome P450IA1 in rat colonic mucosa after a single intragastric injection of 3-methylcholanthrene (3MC, 20 mg/kg) was investigated by examining the drug-metabolizing enzyme activity, immunoblotting for cytochrome P450IA1 and immunohistochemistry. 7-Ethoxycoumarin-O-deethylase activities were approximately 20-fold higher in microsomes from both proximal and distal portions of the colonic mucosa of control diet-fed 3MC-treated rats compared with those of control diet-fed untreated rats. Strong immunofluorescence for cytochrome P450IA1 was localized in the cytoplasm of the colonic mucosa surface epithelium from the control diet-fed 3MC-treated rats. 7-Ethoxycoumarin-O-deethylase activity and cytochrome P450IA1 content determined by immunoblotting were significantly lower in wheat bran-fed 3MC-treated rats than in control diet-fed 3MC-treated rats. Immunohistochemical analysis showed much weaker immunofluorescence for cytochrome P450IA1 in the surface epithelium of the colonic mucosa of the wheat bran-fed 3MC-treated rats. These observations suggested that dietary fiber can affect the induction of cytochrome P450IA1 in colonic mucosa by dietary inducers or carcinogens.     

BUN/Cr ratio as an index of gastrointestinal bleeding mass in children.

Determining the site and severity of blood loss is important in the management of children with gastrointestinal (GI) bleeding. Blood urea nitrogen (BUN) and serum creatinine (Cr) were measured on the day of hospitalization and the ratio of BUN/Cr was calculated in 11 children with 16 episodes of upper GI bleeding and 49 with lower GI bleeding. There was a significant difference between the two GI bleeding groups with regard to BUN/Cr ratio (p less than 0.001). When the ratio was 30 or above, the specificity of upper GI bleeding was 98% with a sensitivity of 68.8%. A linear relationship was found between the BUN/Cr ratio and delta Hb (delta Hb = 0.08 x BUN/Cr +/- 0.8 g/dl) for bleeding originating from the upper GI tract. This study confirms that measurement of the BUN/Cr ratio is useful for localizing the source of bleeding to the upper GI tract and also demonstrates its usefulness as an estimation of the severity of blood loss from the upper GI tract.     

Molecular cloning, characterization, and overexpression of ERG7, the Saccharomyces cerevisiae gene encoding lanosterol synthase.

We report the cloning, characterization, and overexpression of Saccharomyces cerevisiae ERG7, which encodes lanosterol synthase [(S)-2,3-epoxysqualene mutase (cyclizing, lanosterol forming), EC 5.4.99.7], the enzyme responsible for the complex cyclization/rearrangement step in sterol biosynthesis. Oligonucleotide primers were designed corresponding to protein sequences conserved between Candida albicans ERG7 and the related Arabidopsis thaliana cycloartenol synthase [(S)-2,3-epoxysqualene mutase (cyclizing, cycloartenol forming), EC 5.4.99.8]. A PCR product was amplified from yeast genomic DNA using these primers and was used to probe yeast libraries by hybridization. Partial-length clones homologous to the two known epoxysqualene mutases were isolated, but a full-length sequence was found neither in cDNA nor genomic libraries, whether in phage or plasmids. Two overlapping clones were assembled to make a functional reconstruction of the gene, which contains a 2196-bp open reading frame capable of encoding an 83-kDa protein. The reconstruction complemented the erg7 mutation when driven from either its native promoter or the strong ADH1 promoter.     

Thinning of ventricular septum in tetralogy of Fallot]

Cross sectional echocardiography was used to evaluate the thickness of the ventricular septum in tetralogy of Fallot (TOF). Forty-six patients with TOF and 20 patients with pseudo-truncus arteriosus underwent echocardiography during a five-year period beginning in 1984. Thicknesses of the right ventricular anterior wall (RVAWT), trabecular septum (IVST) and left ventricular posterior wall (LVPWT) were measured in end diastole on parasternal short axis view at the level of the tips of papillary muscles. The ratios of IVST to RVAWT and IVST to LVPWT were assessed. The ratio of IVST to RVAWT was 1.09 +/- 0.15 in the group aged less than 7 years (less than 7 y.o.) and 0.94 +/- 0.15 in the group aged of 7 years or more (greater than = 7 y.o.). The ratios of IVST to LVPWT were 1.10 +/- 0.14 (less than 7 y.o.) and 0.90 +/- 0.15 (greater than = 7 y.o.), respectively. Both ratios were significantly different (p less than 0.01) in the two age groups, and relative thinning of the septum was demonstrated in the older patients. It is speculated that thinning of the interventricular septum is caused by the lower systolic wall stress of the ventricular septum compared with that of the free walls, which is produced under equal systolic pressure of the two ventricles. It is suggested that this thinning is one of the factors that reduces left ventricular function after repair of TOF.     

Invasive mycosis in solid organ transplantation]

Invasive mycosis in solid organ transplantation is mainly caused by Candida and Aspergillus, and its risk is higher in small bowel, liver, pancreas, and lung transplantation. Although limited analyses propose not a few risk factors for invasive mycosis in respective transplanted organs, the efficacy of prophylactic use of antifungal agents or preemptive treatments based on the information is not fully supported by prospective randomized controlled clinical data. The final guideline should be helpful for tailor-made evidence-based management based on the stratification of patients by pretransplant, surgical, immunosuppressive and organ specific characteristics. The process of repeated proposals and verification in a large number of patients is necessary.     

An automated on-line method for simultaneous analysis of phenothiazines in human serum by high-performance liquid chromatography/sonic spray ionization mass spectrometry using backflush column switching

An automated on-line method for simultaneous analysis of five phenothiazine drugs by high-performance liquid chromatography (HPLC)/sonic spray ionization mass spectrometry (SSI-MS) has been established, using backflush column switching. A 400-μl portion of serum sample diluted 81-fold with distilled water was subjected to the on-line system. In the system, an Oasis HLB cartridge was used as the precolumn for extraction; large molecules such as proteins in serum were discarded by use of distilled water containing 0.1% formic acid as a mobile phase. After switching a valve, the analytes trapped in the precolumn were eluted in the backflush mode and separated by a Chromolith Performance RP-18e column, which is composed of C₁₈-bonded monolithic silica. The column effluents were then introduced into the SSI-MS. The present method provided successful separation and determination of six phenothiazines including an internal standard. Satisfactory linearities, reproducibility, and sensitivity were obtained at concentration levels that matched the toxic levels of phenothiazines. All drug peaks appeared within 18 min, and the system could be reequilibrated in only about 8 min for the next run. Because of the simplicity and rapidness of the method, it is likely to be useful in the fields of emergency medicine and forensic toxicology.     

Imaging of a large collection of human embryo using a super-parallel MR microscope.

Using 4 and 8-channel super-parallel magnetic resonance (MR) microscopes with a horizontal bore 2.34T superconducting magnet developed for 3-dimensional MR microscopy of the large Kyoto Collection of Human Embryos, we acquired T(1)-weighted 3D images of 1204 embryos at a spatial resolution of (40 microm)(3) to (150 microm)(3) in about 2 years. Similarity of image contrast between the T(1)-weighted images and stained anatomical sections indicated that T(1)-weighted 3D images could be used for an anatomical 3D image database for human embryology.     

Bilateral symmetric tonic posturing suggesting propagation to the supplementary motor area in a patient with precuneate cortical dysplasia.

We report a patient manifesting seizures with bilateral symmetric tonic posturing, which were markedly reduced after resection of the left precuneus. A 16-year-old man had sudden onset, complex partial seizures with bilateral symmetric tonic posturing since the age of eight years. Magnetic resonance fluid-attenuated inversion-recovery imaging revealed a hyperintense lesion in left precuneus. In almost all focal seizures recorded during an invasive EEG evaluation, ictal onset was detected from the inferomesial aspect of the lesion, but fast paroxysmal discharges from the ipsilateral supplementary motor area (SMA) were observed just before the clinical onset. After surgical excision of the EEG onset zone, including the lesion, seizure frequency was markedly (> 95%) reduced. By the 20th month after surgery, there were only brief nocturnal seizures involving slight elevation of both shoulders and slight abduction of both arms, with preservation of consciousness occurring once every few days. Invasive EEG findings and surgical outcome suggested that the epileptic activity originating from the epileptogenic zone may have propagated to the symptomatogenic zone including mainly the ipsilateral SMA. In summary, we report an interesting case of bilateral symmetric tonic posturing suggesting propagation to the SMA. MRI and invasive EEG confirmed the epileptogenic focus as a precuneate cortical dysplasia lesion.[Published with video sequences].