Selective expression of light-harvesting complexes alters phospholipid composition in the intracytoplasmic membrane and core complex of purple phototrophic bacteria.

Phospholipid-protein interactions play important roles in regulating the function and morphology of photosynthetic membranes in purple phototrophic bacteria. Here, we characterize the phospholipid composition of intracytoplasmic membrane (ICM) from Rhodobacter (Rba.) sphaeroides that has been genetically altered to selectively express light-harvesting (LH) complexes. In the mutant strain (DP2) that lacks a peripheral light-harvesting (LH2) complex, the phospholipid composition was significantly different from that of the wild-type strain; strain DP2 showed a marked decrease in phosphatidylglycerol (PG) and large increases in cardiolipin (CL) and phosphatidylcholine (PC) indicating preferential interactions between the complexes and specific phospholipids. Substitution of the core light-harvesting (LH1) complex of Rba. sphaeroides strain DP2 with that from the purple sulfur bacterium Thermochromatium tepidum further altered the phospholipid composition, with substantial increases in PG and PE and decreases in CL and PC, indicating that the phospholipids incorporated into the ICM depend on the nature of the LH1 complex expressed. Purified LH1-reaction center core complexes (LH1-RC) from the selectively expressing strains also contained different phospholipid compositions than did core complexes from their corresponding wild-type strains, suggesting different patterns of phospholipid association between the selectively expressed LH1-RC complexes and those purified from native strains. Effects of carotenoids on the phospholipid composition were also investigated using carotenoid-suppressed cells and carotenoid-deficient species. The findings are discussed in relation to ICM morphology and specific LH complex-phospholipid interactions.

Phospholipid distributions in purple phototrophic bacteria and LH1-RC core complexes.

In contrast to plants, algae and cyanobacteria that contain glycolipids as the major lipid components in their photosynthetic membranes, phospholipids are the dominant lipids in the membranes of anoxygenic purple phototrophic bacteria. Although the phospholipid compositions in whole cells or membranes are known for a limited number of the purple bacteria, little is known about the phospholipids associated with individual photosynthetic complexes. In this study, we investigated the phospholipid distributions in both membranes and the light-harvesting 1-reaction center (LH1-RC) complexes purified from several purple sulfur and nonsulfur bacteria. 31P NMR was used for determining the phospholipid compositions and inductively coupled plasma atomic emission spectroscopy was used for measuring the total phosphorous contents. Combining these two techniques, we could determine the numbers of specific phospholipids in the purified LH1-RC complexes. A total of approximate 20-30 phospholipids per LH1-RC were detected as the tightly bound lipids in all species. The results revealed that while cardiolipin (CL) exists as a minor component in the membranes, it became the most abundant phospholipid in the purified core complexes and the sum of CL and phosphatidylglycerol accounted for more than two thirds of the total phospholipids for most species. Preferential association of these anionic phospholipids with the LH1-RC is discussed in the context of the recent high-resolution structure of this complex from Thermochromatium (Tch.) tepidum. The detergent lauryldimethylamine N-oxide was demonstrated to selectively remove phosphatidylethanolamine from the membrane of Tch. tepidum.

Induction of apoptosis by gallic acid in lung cancer cells.

The apoptosis-inducing effect of gallic acid (3,4,5-trihydroxybenzoic acid) was investigated in four human lung cancer cell lines, SBC-3 (small cell carcinoma), EBC-1 (squamous cell carcinoma), A549 (adenocarcinoma) and SBC-3/CDDP (cisplatin-resistant subclone of SBC-3). Gallic acid induced apoptosis in a dose-dependent manner as evidenced by analyses of DNA fragmentation, changes in cell morphology and loss of viability. Fifty percent inhibitory concentration (IC50) values of gallic acid on the cell viability of SBC-3, EBC-1 and A549 were around 10, 20 and 60 microg/ml, respectively. The IC50 value for SBC-3/CDDP cells was almost the same as that of SBC-3, suggesting that susceptibility of cells to gallic acid-induced apoptosis is not altered by the acquisition of cisplatin resistance. The apoptotic process was effectively triggered by 30 min exposure to gallic acid. A caspase inhibitor and alpha-tocopherol effectively prevented the gallic acid-induced apoptosis, indicating the involvememt of caspase activation and oxidative processes during the course of apoptosis in gallic acid-treated cancer cells. These findings suggest the possible applicability of gallic acid in lung cancer therapy, especially to circumvent resistance to anti-cancer drugs.

[The anesthetic management of patients in chronic renal failure for coronary artery bypass surgery without cardiopulmonary bypass].

We describe our experience with three patients in chronic renal failure who underwent coronary artery bypass surgery without cardiopulmonary bypass. Anesthesia was maintained with fentanyl and midazolam. Nitroglycerin and prostaglandin E1 were administered during the surgical procedure. When the coronary artery was clamped for the anastomosis of the graft, cardiac output and arterial pressure decreased in all cases. The patients were treated with ephedrine and dobutamine, which restored the hemodynamics. The important points for the anesthetic management for this operation are follows: the adequate administration of the coronary vasodilator, and attention to the change of hemodynamics on clamping the coronary artery.

A low frequency, high amplitude rhythmic fluctuation of laser-Doppler skin blood flow after subarachnoid phenol block.

A 51-year-old male with a huge chondrosarcoma received subarachnoid dorsal root blocks with 10% phenol in glycerine to treat severe pain along the left leg. The dermatomes below the Th9 lost all somatic sensation on the left side after the nerve blocks, but the patient was not completely relieved from the pain. Laser-Doppler flowmetry on the toe of the left foot disclosed an increased blood flow and an abnormal fluctuation of the cutaneous capillary blood flow, i.e. a high amplitude rhythmic (HAR) wave with 2.5 to 3 cycles.min-1. The low frequency HAR wave persisted for the subsequent 3 months until a tingling sensation returned to the left leg. It would seem that some travelling roots of the sympathetic nerve were preserved from the chemical neurolysis and the remaining efferent and afferent nerve fibers were responsible for the persisting low frequency HAR wave and pain in the left leg.

[A case of endodermal sinus tumor in the basal ganglia associated with Down's syndrome].

A case of Down's syndrome accompanied by endodermal sinus tumor of the left basal ganglia is reported. She was referred to us because of right hemiparesis. A CT scan showed a calcified mass in the left basal ganglia, which was well enhanced on contrast CT. Emergency removal of the tumor was performed because of its rapid growth, intratumoral hemorrhage, and acute hydrocephalus. The histological diagnosis established after surgery was endodermal sinus tumor. Alphafetoprotein-positive cells were seen in the resected tumor by light microscopy. Postoperative irradiation was very effective, and the high level of serum alphafetoprotein decreased during the course of irradiation. The residual tumor, enhanced on contrast CT, was treated by administration of cisplatin and etoposide after irradiation. Cases of malignant tumors other than leukemia, which are associated with Down's syndrome, are extremely rate. To our knowledge, including three cases of germ cell tumor, there have been only nine cases of brain tumors associated with Down's syndrome reported previously.

[Comparison of two hours' biofiltration and four hours' bicarbonate hemodialysis by multiple clinical parameters].

Ten uremic patients maintained stable on regular dialysis treatment participated in a comparison study of 2 hours' biofiltration and 4 hours' bicarbonate hemodialysis with informed consents. In biofiltration, ultrafiltrate was replaced by a solution consisting of Na 145 mEq/l, HCO3- 100 and Cl 45 at the infusion rate 2.51/hour. Dialysate composition was Na 130-149 mEq/l, K 1.0, Cl 119, Ca 2.5, Mg 0.5, CH3COO- 15 and glucose 200 mg/dl. Hemodiafilter was F80, polysulphone, 1.9 m2, manufactured by Fresenius Co. Ltd. Blood flow rate was 5 ml/min/kg.body.weight to keep urea index (Kt/V) over 1.0. B-A-B' comparison was designed in which B and B' stand for 4 hours' bicarbonate hemodialysis while A for 2 hours' biofiltration, 3 times per week for 2 months, respectively. It was intended to find out if there are aggravations of clinical parameters in A after B and/or improvements in B' after A in view of evaluation of optimum for 2 hours' biofiltration. One patient was withdrawn from biofiltration at 15th treatment in A because of frequent muscular twitchings. Others finished the whole program, thus making drop-out rate 10%. No significant differences were observed in the following parameters between B and A and between A and B': cardiothoratic ratio, pre-treatment blood pressure, human atrial natriuretic hormone, cardiovascular dynamics, total protein, BUN, serum creatinine, uric acid, beta 2 microglobulin, blood counts, blood gas analysis, electrolytes, alkaline-phosphatase, PTH-C, protein catabolic rate (PCR), lipids and liver functions.(ABSTRACT TRUNCATED AT 250 WORDS)

[A case of colloid cyst of the third ventricle].

Colloid cysts of the third ventricle are rare, accounting for less than 1% of all intracranial neoplasms. However, its incidence will increase with increased use of CT scan and MRI. The symptomatology is principally acute or chronic hydrocephalus obstructing the foramen of Monro, and the origin of this cyst is controversial, neuroepithelial or endodermal. We report a case of colloid cyst of the third ventricle, associated with cavum veli interpositi. The patient, a 46-years-old female, had suffered from headache, ataxic gait and tremor lasting 6 months. CT scan and homogenous high signal intensity by SR (2450/450) MR image, detected a small round mass in the anterior part of the third ventricle that was of homogenous high density, but without the effect of enhancement. The lateral ventricle was markedly dilated, and a large cavum veli interpositi was found between the third ventricle and the corpus callosum. The cyst was totally removed by transventricular approach, and the result was satisfactory. We reviewed literatures and discussed MRI findings of colloid cysts of the third ventricle. Because of the presence of microvilli covered with coating materials seen in electron microscopic study, we suggested that the colloid cyst was endodermal in origin.