Triterpenoidal saponins from the bark of Kalopanax pictum var. typicum

One new triterpenoidal saponin, saponin F(2) has been isolated from the bark of Kalopanax pictum Nakai var. typicum (Araliaceae), together with one known saponin, kizuta saponin K12 (1). On the basis of chemico-spectral evidences, the structure of 2 has been elucidated to be 3-O-beta-D-xylopyranosyl(1-->3)-alpha- L-rhamnopyranosyl(1-->2)-alpha- L-arabinopyranosyl-23-hydroxyolean-12-en-28-O-alpha-L- rhamnopyranosyl(1-->4)-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranosy l ester.

Versicolorin A hemiacetal, hydroxydihydrosterigmatocystin, and aflatoxin G2 alpha reductase activity in extracts from Aspergillus parasiticus

Versicolorin A hemiacetal was converted to versicolorin C in cell-free systems from Aspergillus parasiticus. The rate of reaction catalyzed by the 35-70% ammonium sulfate fraction was 0.43 nmol min-1 mg-1 with NADPH as cosubstrate and 0.17 nmol min-1 mg-1 with NADH at 25 degrees C at pH 7.4. The product from incubation of 17-hydroxy-16,17-dihydrosterigmatocystin with the 35-70% ammonium sulfate fraction and NADPH was a polar compound which was converted to dihydrosterigmatocystin by 0.4 M HCl. The polar compound is proposed to be the 14,17-hydrated open-chain derivative of dihydrosterigmatocystin. Aflatoxin G2 alpha was also reduced in this system to a polar product tentatively identified as the 13,16-hydrated open-chain derivative of AFG2. The reductase activity may be involved in the formation of reduced intermediates and aflatoxins in cultures of A. parasiticus.

Warm growth temperatures decrease soybean cholinephosphotransferase activity

The activity of cytidine 5'-diphosphate (CDP) choline: 1,2-diacylglycerol cholinephosphotransferase (EC 2.7.8.2) in developing soybean (Glycine max L. var Williams 82) seeds was 3 to 5 times higher in cotyledons grown at 20 degrees C than in those grown at 35 degrees C. Some characteristics of the enzyme from cotyledons cultured at 20 and 35 degrees C were compared. In preparations from both growth temperatures, the enzyme showed a pH optimum of 7, K(m) of 7.0 micromolar for CDP-choline, and an optimum assay temperature of 45 degrees C. Both enzyme preparations were stimulated by increasing concentrations of Mg(2+) or Mn(2+), up to 10 millimolar and 50 micromolar, respectively, though Mn(2+) produced lower activities than Mg(2+). Enzymes from both 20 and 35 degrees C show the same specificity for exogenous diacylglycerol. No metabolic effectors were detected by addition of heat treated extracts to the assay mixture. The above findings suggest that the higher enzyme activity at 20 degrees C can be attributed to a higher level of the enzyme rather than to the involvement of isozymes or metabolic effectors. Enzyme activity decreased rapidly during culture at 35 degrees C, indicating a rapid turnover of the enzyme. The level of temperature modulation was found to be a function of seed developmental stage.

Galactolipids of Thylakoid Pigment Protein Complexes Separated Electrophoretically from Thylakoids of Dunaliella salina Labeled with Radioactive Fatty Acids

Experiments have been conducted to determine whether mono- and digalactosyldiacylglycerols (MGDG and DGDG) labeled by short term exposure of the green alga Dunaliella salina to exogenous radioactive lauric, myristic, or palmitic acids are preferentially recovered in one or more thylakoid protein complexes separated by electrophoresis on nondenaturing gels. A selective retention of certain lipid classes and molecular species by the major electrophoretically separable fractions, oligomeric form (LHCP-1) and monomeric form (LHCP-3) of hight-harvesting chlorophyll a/b protein complex, and major photosystem I protein complex (CPla), and nonprotein-bound lipids, was indicated. After 5 min of labeling with (3)H-palmitate the specific radioactivities of MGDG and DGDG molecular species recovered from LHCP-3 and CPla were slightly higher and lower, respectively, than specific radioactivities of equivalent molecular species from LHCP-1 and nonprotein-bound lipid. However, the differences were smaller than those which have been observed between whole thylakoids and the more highly labeled chloroplast envelopes from briefly labeled cells.

Two-year survival: preoperative adjuvant chemotherapy in the treatment of cervical cancer stages Ib and II with bulky tumor

The effect of preoperative adjuvant chemotherapy on the 2-year survival rate of patients with locally advanced cervical cancer (stages Ib and II with bulky tumour) was evaluated. The 54 patients first received initial chemotherapy of vinblastine, bleomycin, and cis-platinum in a combined regimen (VBP) and then radical hysterectomy. The overall histologic response rate to chemotherapy of the primary tumor confirmed in the surgical specimen was 81% including microscopic or no evidence of disease (41%, Grade III or IV). A lower than expected incidence of lymph node metastasis (20%) was found. All nodal metastasis was noted in patients with Grades I or II (P = 0.0034). Median follow-up was 36 months (range 26-60 months). Three recurrences (6%) appeared and those patients died of the disease within 24 months. Thus the 2-year tumour-free survival rate was 94%. The patients who had positive nodes more often experienced recurrence (27 vs 0%) and a lower 2-year survival rate (72 vs 100%) (P = 0.0067). All of these recurrences were found in patients with three or more positive nodes. This preliminary study suggest that preoperative adjuvant chemotherapy (VBP) is effective (1) in reducing tumour volume or the stage of the disease, (2) in curing the lymph node involvement, and (3) in improving the 2-year tumour-free survival rate. A prospective randomized study comparing radical surgery alone with preoperative adjuvant chemotherapy followed by radical surgery is in progress.

Alveolar hemorrhage associated with crescentic glomerulonephritis--a case report

Alveolar hemorrhage is a life threatening condition which requires an urgent diagnosis and treatment. We report a case of alveolar hemorrhage associated with crescentic glomerulonephritis without immune complex deposition with a review of the literature.

Prevention of hereditary cardiomyopathy in the Syrian hamster with chronic verapamil therapy

The cardiomyopathic Syrian hamster develops genetically determined cardiac necrosis that invariably leads to premature death from congestive heart failure or arrhythmia. This hamster is a valuable model of human disease because it has many features in common with clinical dilated, congestive cardiomyopathy. Previous studies have shown that therapy for several weeks with the calcium channel blocking drug verapamil or the alpha-1 adrenoceptor blocking drug prazosin can prevent myocardial necrosis due to microvascular spasm. Other investigations have demonstrated the positive effects of verapamil in the early stages of disease. It is not clear, however, whether continued treatment can prevent the long-term expression of the cardiomyopathy or whether the disease is genetically predetermined. To address this question, hamsters were treated with oral verapamil for 7 to 8 months during the necrotizing, compensatory hypertrophy and early failure stages of disease. Analysis of myocardial pathologic and biochemical variables demonstrated that continuously treated animals were generally similar to unaffected control hamsters; discontinuous therapy led to partial protection. These findings demonstrate that virtually complete prevention of this hereditary disease is feasible; these results may have important implications for the treatment of human cardiomyopathy.

A factor in human seminal plasma which affects carnitine accumulation in bovine epididymal sperm

This study was initiated to determine whether factors are present in human sperm-free seminal plasma (HSP) that regulate the uptake and release of carnitine from sperm. Bovine caput epididymal sperm cells accumulated more carnitine than caudal sperm cells. A significant reduction in carnitine uptake by caput sperm was observed in the presence of HSP from normal subjects, but not from three subjects with reduced motility. A factor has been isolated from HSP that inhibits carnitine uptake by caput sperm and has the following properties: it is nondialyzable, stable to freeze-thawing, soluble in 60% ammonium sulfate, and has an approximate molecular weight of 158 kd. These data are consistent with the existence of a relatively high molecular weight protein in HSP responsible for the preservation of carnitine concentrations in sperm.

Preoperative adjuvant chemotherapy in the treatment of cervical cancer stage Ib, IIa, and IIb with bulky tumor

Thirty-five previously untreated patients with stage Ib, IIa, and IIb squamous cell carcinoma of uterine cervix with bulky mass (more than 4 cm) were treated with initial chemotherapy of vinblastine, bleomycin, and cis-platinum combined regimen (VBP, one to five courses) and subsequent radical surgery. The effectiveness of the preoperative chemotherapy was evaluated in the surgical specimen. The overall clinical response rate was 89% and included a complete response in 16 (46%) and a partial response in 15 patients (43%). There were no differences in the response rate by age, stage, or the geographic contour of the tumor. The number of chemotherapeutic courses correlated well with the response of the primary tumor (P = 0.0004) up to three courses. Histologic examination of the resected primary tumor revealed no evidence of disease (Grade IV) in 44% of complete responders, microscopic foci (Grade III) in 38% (6), and macroscopic disease (Grade II) in 18% (3). Of 15 patients with stage IIb, 11 (73%) had a stage-down. Lymphnode metastases after chemotherapy were found in 26% (9/35) of the patients. All nodal metastases were found among the patients who had a partial response or a stable disease, and none was found in those with a complete response (P = 0.0029). This preliminary study suggests that initial chemotherapy before surgery is effective in reducing tumor volume or stage of the disease providing better circumstances for surgery, offers selection of high-risk groups of patients requiring additional chemotherapy, and might be able to eliminate effectively diseases in lymphnodes and possibly micrometastases. This regimen is now being evaluated to test its impact on survival.

Metabolism of exogenous long-chain fatty acids by spinach leaves

When applied in liquid paraffin to the upper surface of expanding spinach leaves, [1-14C]palmitic acid was efficiently and exclusively incorporated into the sn-1 position of cellular glycerolipids, principally phosphatidylcholine and triacylglycerol. A slow transfer of fatty acids from phosphatidylcholine to chloroplast glycolipids subsequently occurred with the positional specificity of the label remaining intact. Labeled palmitate at the sn-1 position of monogalactosyldiacylglycerol was desaturated to hexadecatrienoate so that 1-[14C]hexadecatrienoyl-2-linolenoyl-3-galactosoylglycerol became the major labeled species of the lipid between 8 and 24 h. There was no evidence of deacylation/reacylation reactions modifying the acyl compositions of spinach leaf glycerolipids for at least 48 h after labeling with [1-14C]palmitic acid; even the partially prokaryotic glycerolipids remained firmly labeled at the sn-1 position. Exogenous [1-14C]stearic acid was also incorporated into the sn-1 position of MGD, presumably by the same mechanism, and was there desaturated to [14C]linolenate. Exogenous [1-14C]oleic acid was initially incorporated equally into both sn-1 and sn-2 positions of phosphatidylcholine, and was desaturated to linoleate at both positions before the label was rapidly transferred to monogalactosyldiacylglycerol. There, desaturation of linoleate to linolenate took place. Galactolipids remained equally labeled at both positions throughout the 6 days of the experiment, but label was concentrated in the 1-saturated-2-[14C]linolenoyl molecular species of phosphatidylcholine as those species with two [14C]linoleoyl residues were drawn off for monogalactolipid synthesis. Glycerolipids synthesised from exogenous [1-14C]acetate by spinach leaves were labeled equally at both the sn-1 and the sn-2 positions. These results are interpreted as providing strong support for the two-pathway scheme of glycerolipid synthesis in plants.

On the metabolic relationships between monogalactosyldiacylglycerol and digalactosyldiacylglycerol molecular species in Dunaliella salina

Dunaliella salina cells were pulse-labeled for 2 min with [14C]palmitic acid, [14C]oleic acid, or [14C]lauric acid in order to trace the pathway of galactolipid biosynthesis and desaturation. Through the use of high performance liquid chromatography it was possible to follow the movement of radioactivity through many individual molecular species of monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) for periods of 24 h and, in some cases, as much as 120 h. Analysis of the fatty acid fluxes permitted us to refine current views regarding biosynthesis of the predominantly "prokaryotic" galactolipids. The initial D. salina MGDG molecular species, containing paired oleate and palmitate (18:1/16:0), can follow two metabolic routes. If the palmitoyl chain is desaturated to 16:1, the resulting 18:1/16:1 MGDG is subject to rapid further desaturation to varying degrees, and a part of these products is subsequently galactosylated to DGDG. Contrary to widely held opinions, these DGDG molecular species can themselves be further desaturated toward a 18:3/16:4 final product. In a separate series of reactions, a smaller portion of the nascent 18:1/16:0 MGDG is directly galactosylated to 18:1/16:0 DGDG. This molecular species can then be sequentially desaturated to 18:2/16:0 DGDG and 18:3/16:0 DGDG. However, there is only very limited desaturation of the palmitoyl group attached to these molecular species.

Alterations of the myocardial skeletal framework in acute myocardial infarction with and without ventricular rupture. A preliminary report

Thinning and dilatation (expansion) of the infarct region and complete rupture of the ventricular wall are significant complications of acute transmural myocardial infarction associated with increased morbidity and mortality. The pathogenesis of these related events is unknown. Recent studies of myocardial connective tissue have delineated an extensive array of intercellular and pericellular structures which serve as a skeletal framework and which may modulate contractile activity. We have employed a modified silver impregnation method to visualize the connective tissue components by light microscopy. To explore whether the skeletal framework is altered in acute myocardial infarction with and without ventricular rupture, we studied 9 human hearts at autopsy, and 4 canine infarcts of known duration. The human infarctions included 4 nonruptured cases with infarcts 1-5 days old, and 5 ruptured cases with infarcts 3-10 days old. Sections from normal, lateral, and central infarct or ventricular rupture sites were stained with silver. The normal tissue from each heart served as a control. Silver staining was moderately decreased in the lateral infarct zones, and markedly decreased in the central non-ruptured infarct zones. In the 5 ventricular rupture cases, the rupture site had no silver staining. A similar pattern was observed in the 4 canine infarcts. Thus, we conclude that the skeletal framework is markedly altered in the central zone of acute myocardial infarction. The acute changes of silver stained connective tissue may contribute significantly to the development of infarct expansion or ventricular wall rupture.

Isolation and quantitative analysis of phosphatidylglycerol and glycolipid molecular species using reversed-phase high-performance liquid chromatography with flame ionization detection

Conditions are described for the quantitative analysis of phosphatidylglycerol and plant glycolipid molecular species by reversed-phase high-performance liquid chromatography employing a commercially available flame ionization detector. Direct detection on a mass basis overcomes the problem of poor detectability found with most natural lipids. Effective mobile phases composed primarily of volatile solvents are described. Splitting of the column eluate stream allows a portion of each individual molecular species to be recovered for other types of analysis.

Model for cooperativity of biological membranes

We present a mathematical model for the complex cooperativity observed in biological membranes. In our model, it is assumed that the proteins bound on the membrane are noncooperative and possess a Bohr proton. It is further assumed that the net charge of the unliganded state of the protein is different from that of the liganded state owing to the structural change upon binding the ligand. With this model, we show how an all-or-none response, a graded response, and a noncooperative response arise in the binding curve of such biological membranes. In addition, we show how an effector, which can alter the pKa involved in the binding site, induces a complex cooperativity.

On exploring the basis for slow and fast oscillations in cellular systems

We show that interesting oscillatory patterns may arise from an immobilized enzyme system, when the enzyme has the properties that it is inhibited by a substrate, produces H+ and has a pH-activity curve of bell-shaped form. In agreement with experimental observations in cellular excitations, the system generates fast oscillations that are superimposed on a slow cycle, at certain salt and enzyme concentrations.

Dural arteriovenous malformation of the major venous sinuses: an acquired lesion

Arteriovenous malformations of the dura are thought to be congenital. However, arteriographic investigations of four patients who, after a head injury, developed dural arteriovenous fistulae with features of congenital malformations suggest that these abnormal communications may also be acquired. Thrombosis or thrombophlebitis in the dural sinus or vein may be the primary event in their formation. The pathogenesis is probably "growth" of the dural arteries normally present in the walls of the sinuses during the organization of an intraluminal thrombus. This may result in a direct communication between artery and vein or sinus, establishing an abnormal shunt. Ultimate fibrosis of the sinus wall and intraluminal thrombus may be the factors responsible for the spontaneous disappearance of such malformations.

Ray method for unstable resonators

The previously developed ray-optical method for unstable, symmetric, bare resonators with sharp-edged stop and circular mirrors is reviewed here. A deductive stepwise procedure is presented, with emphasis on the physical implications. It is shown how the method can accommodate other edge configurations such as those produced by rounding, and also more complicated nonaxial structures such as the half-symmetric resonator with internal axicon. For the latter, the ray approach categorizes those rays that must be eliminated from the equivalent aligned unfolded symmetric resonator, and it identifies the canonical diffraction problems that must be addressed to account for shadowing and scattering due to the axicon tip. Effects due to shielding or truncation of the axicon tip are also considered. Approximate calculations of the eigenvalues for the lowest-loss modes illustrate the effects due to various tip shielding lengths and spacings of the axicon from the output mirror.

Shock tube coupled to the time-of-flight mass spectrometer via a molecular beam sampling system

A method for continuous mass spectrometric analysis of high-temperature reacting gas mixtures is described. The apparatus consists of a unique combination of three devices: the shock tube, the time-of-flight mass spectrometer, and the supersonic molecular beam. The driven section of the shock tube constitutes the reservoir of a supersonic molecular beam by which gas is continuously extracted from the reaction zone and introduced through a two-stage high-capacity vacuum system into the ionization region of the mass spectrometer. The shock tube and the mass spectrometer are coupled at right angles to one another. This configuration avoids excessive pressure buildup in the mass spectrometer system. The apparatus has an estimated mass resolution of 100 amu, a frequency range of 10-100 kHz, and can be operated over a wide range of shock conditions during the complete high-temperature pulse.