Intramyocardial Injections to De-Stiffen the Heart: A Subject-Specific in Silico Approach

We hypothesized that minimally invasive injections of a softening agent at strategic locations in stiff myocardium could de-stiffen the left ventricle (LV) globally. Physics-based finite element models of the LV were created from LV echocardiography images and pressures recorded during experiments in four swine. Results confirmed animal models of LV softening by systemic agents. Regional de-stiffening of myocardium led to global de-stiffening of LV. The mathematical set up was used to design LV global de-stiffening by regional softening of myocardium. At an end diastolic pressure of 23 mmHg, when 8 ml of the free wall was covered by intramyocardial injections, end diastolic volume (EDV) increased by 15.0%, whereas an increase up to 11 ml due to intramyocardial injections in the septum and free wall led to a 26.0% increase in EDV. Although the endocardial intramyocardial injections occupied a lower LV wall volume, they led to an EDV (44 ml) that was equal compared to intramyocardial injections in the mid-wall (44 ml) and larger compared to intramyocardial injections in the epicardium (41 ml). Using an in silico set up, sites of regional myocardium de-stiffening could be planned in order to globally soften overly stiff LV in heart failure with preserved ejection fraction. This novel treatment is built on subject-specific data. Hypothesis-testing of these simulation findings in animal models is warranted.     

A Method for Staining Pollen Tubes in Pistil

A quadruple staining procedure has been developed for staining pollen tubes in pistil. The staining mixture is made by adding the following in the order given: lactic acid, 80 ml; 1% aqueous malachite green, 4 ml; 1% aqueous acid fuchsia, 6 ml; 1% aqueous aniline blue, 4 ml; 1 % orange G in 50% alcohol, 2 ml; and chloral hydrate, 5 g. Pistils are fixed for 6 hr in modified Carnoy's fluid (absolute alcohol:chloroform:glacial acetic acid 6:4:1), hydrated in descending alcohols, transferred to stain and held there for 24 hr at 45±2 C They were then transferred to a clearing and softening fluid containing 78 ml lactic acid, 10 g phenol, 10 g chloral hydrate and 2 ml 1% orange G. The pistils were held there for 24 hr at 45±2 C, hydrolyzed in the clearing and softening fluid at 58±1 C for SO min, then stored in lactic acid for later use or immediately mounted in a drop of medium containing equal parts of lactic acid and glycerol for examination. Pollen tubes are stained dark blue to bluish red and stylar tissue light green to light greenish blue. This stain permits pollen tubes to be traced even up to their entry into the micropyle.     

A method for staining pollen tubes in pistil

A quadruple staining procedure has been developed for staining pollen tubes in pistil. The staining mixture is made by adding the following in the order given: lactic acid, 80 ml; 1% aqueous malachite green, 4 ml; 1% aqueous acid fuchsin, 6 ml; 1% aqueous aniline blue, 4 ml; 1% orange G in 50% alcohol, 2 ml; and chloral hydrate, 5 g. Pistils are fixed for 6 hr in modified Carnoy's fluid (absolute alcohol:chloroform:glacial acetic acid 6:4:1), hydrated in descending alcohols, transferred to stain and held there for 24 hr at 45 +/- 2 C. They were then transferred to a clearing and softening fluid containing 78 ml lactic acid, 10 g phenol, 10 g chloral hydrate and 2 ml 1% orange G. The pistils were held there for 24 hr at 45 +/- 2 C, hydrolyzed in the clearing and softening fluid at 58 +/- 1 C for 30 min, then stored in lactic acid for later use or immediately mounted in a drop of medium containing equal parts of lactic acid and glycerol for examination. Pollen tubes are stained dark blue to bluish red and stylar tissue light green to light greenish blue. This stain permits pollen tubes to be traced even up to their entry into the micropyle.     

Fungi Associated with Softening of Bisulfite-Brined Cherries

Softening of sound, calcium bisulfite-brined cherries was induced fairly quickly by brining them with cherries rotted by Aspergillus niger, Cytospora leucostoma, and Penicillium expansum, but not with cherries rotted by a variety of other microorganisms, including Alternaria sp., Aspergillus oryzae, Aureobasidium pullulans, Botrytis cinerea, Cladosporium sp., Mucor racemosus, Rhizopus stolonifer, and Sclerotinia fructicola. Rapid softening was correlated with the presence of a bisulfite-stable polygalacturonase, as demonstrated by a cup-plate test. A survey of naturally rotted cherries suggests the involvement of a bark-canker fungus, C. leucostoma, in softening of commercially brined cherries in the Pacific Northwest.     

F prostaglandin levels in amniotic fluid during balloon-induced cervical softening and labor at term

Mechanical stretching of the uterus was applied to seven term patients not in labor with unripe cervix by means of intra-uterine application of a rubber balloon. Significant cervical softening, and initiation and progress of labor was achieved in all cases. Serial analyses of the F prostaglandins (PGF) in amniotic fluid were performed before and at given intervals of cervical dilatation. Before the application of stretch, the level of PGF varied greatly; the values in 5 cases were measureable but low (less than 645 pg/ml) and in two cases the levels were below the sensitivity of the assay (less than 50 pg/ml). Large fluctuations of the levels were noted in many cases during the treatment. However, the rise of the PGF values was significantly with the progress of cervical dilatation compared to the pre-treatment values (P<0.05 at both 3–4 and 5–6 cm, and P<0.01 at 9–10 cm). It was concluded that the increased release of PGF in amniotic fluid is mediated by uterine stretching, and that upon being released PGF is probably involved in the cervical softening and progress of labor.     

Optimization of cassava fermentation for fufu production: effects of single starter cultures

Single starter cultures were used to ferment cassava for fufu production in a process which involved steeping seeded cassava tubers in water for 96 h. The cultures used include Bacillus subtilis, Klebsiella sp., Lactobacillus plantarum and Candida krusei. Lactobacillus plantarum exhibited the highest acid producing ability, decreasing the pH of the cassava tubers from 6.0 to 3.62, with a corresponding increase in total titratable acidity (TTA) from 0.072% to 0.250% during the 96 h fermentation period. The effected changes in pH and TTA by other organisms ranged respectively from 5.03 and 0.125% for Klebsiella sp., 5.07 and 0.126% for C. krusei , to 5.20 and 0.128% for B. subtilis within the period. Lactobacillus plantarum grew better than other cultures singly inoculated. While all the cultures were found to contribute to the characteristic odour of fufu, C. krusei effected the highest perceived characteristic odour. Also, the cultures variably caused softening of the tubers, with B. subtilis showing the highest softening capability.     

Silver Impregnation of Degenerating Axons in the Central Nervous System: A Modified Technic

Frozen sections of formalin-fixed brains containing surgical lesions, were treated with 15% ethanol for 0.5 hr., soaked in 0.5% phosphomolybdic acid for 0.25-1.0 hr., and subsequently treated with 0.05% potassium permanganate for 4-10 min. (The duration of the latter treatment is critical and individually variable). Subsequent procedure is as follows: decolorize in a mixture of equal parts of 1% hydroquinone and 1% oxalic acid; wash thoroughly and soak sections in 1.5% silver nitrate for 20-30 min.; ammoniacal silver nitrate (silver nitrate 0.9 g., distilled water 20 ml., pure ethanol 10 ml., strong ammonia 1.8 ml., 2.5% sodium hydroxide 1.5 ml.) 0.5-1.0 min.; reduce in acidified formalin (distilled water 400 ml., pure ethanol 45 ml., 1% citric acid 13.5 ml., 10% formalin 13.5 ml.) 1 min.; wash, and pass section through 1 % sodium thiosulf ate (0.5-1.0 min.); wash thoroughly and pass sections through graded alcohols and xylene (3 changes); cover in neutral synthetic resin.     

Registration of T-2 mycotoxin with total internal reflection ellipsometry and QCM impedance methods

A sensitive optical method of total internal reflection ellipsometry (TIRE) in conjunction with immune assay approach was exploited for the registration of T-2 mycotoxin in a wide range of concentrations from 100 microg/ml down to 0.15 ng/ml. Association constants of 1.4x10(6) and 1.9x10(7)mol(-1)s for poly- and monoclonal T-2 antibodies, respectively, were evaluated from TIRE kinetic measurements. According to TIRE data fitting, binding of T-2 molecules to antibodies (at saturation) has resulted in the increase in adsorbed layer thickness of 4-5 nm. The QCM impedance measurements data showed anomalously large mass increase and film softening, most likely, due to the binding of large T-2 aggregates to antibodies.     

Tissue softening of guinea pig oesophagus tested by the tri-axial test machine

Tissue softening is commonly reported during mechanical testing of biological tissues in vitro. The loss of stiffness may be due to viscoelasticity-induced softening (the time-history of load-caused softening) and strain-induced stress softening (the maximum previous load-caused softening). However, the knowledge about tissue softening behaviour is presently poor. The aims of this study were to distinguish whether the loss of the stiffness during preconditioning was due to strain softening or viscoelasticity and to test the tissue softening in circumferential and longitudinal direction in the guinea pig oesophagus. Eight repeated pressure controlled ramp distensions and eight uniaxial tensile-release ramp stretches in three series were done on eight guinea pig oesophagi. The stress–strain curves were used to display the time-dependency (viscoelasticity) and the maximum previous load-caused softening (strain softening) in circumferential and longitudinal directions. For both the longitudinal and the circumferential softening, the peak stress and stiffness produced during the first loading were bigger than those produced in the remaining loadings. The stress loss due to strain softening was about three times more than that due to viscoelasticity in the longitudinal direction. The strain increased more than two times between the strain softening and viscoelastic softening in the circumferential direction. With a stress level of 20 kPa, the stiffness in the circumferential direction lost more than that in the longitudinal direction (P<0.05), indicating the anisotropic softening properties in the oesophagus. In conclusion, the stiffness loss during preconditioning is mainly attributed to strain softening, appears irreversible and is anisotropic.     

A mechanical model for adjustable passive stiffness in rabbit detrusor.

Strips of rabbit detrusor smooth muscle (DSM) exhibit adjustable passive stiffness characterized by strain softening: a loss of stiffness on stretch to a new length distinct from viscoelastic behavior. At the molecular level, strain softening appears to be caused by cross-link breakage and is essentially irreversible when DSM is maintained under passive conditions (i.e., when cross bridges are not cycling to produce active force). However, on DSM activation, strain softening is reversible and likely due to cross-link reformation. Thus DSM displays adjustable passive stiffness that is dependent on the history of both muscle strain and activation. The present study provides empirical data showing that, in DSM, 1) passive isometric force relaxation includes a very slow component requiring hours to approach steady state, 2) the level of passive force maintained at steady state is less if the tissue has previously been strain softened, and 3) tissues subjected to a quick-release protocol exhibit a biphasic response consisting of passive force redevelopment followed by force relaxation. To explain these and previously identified characteristics, a mechanical model for adjustable passive stiffness is proposed based on the addition of a novel cross-linking element to a hybrid Kelvin/Voigt viscoelastic model.     

Manipulation of strawberry fruit softening by antisense expression of a pectate lyase gene

Strawberry (Fragaria x ananassa, Duch., cv Chandler) is a soft fruit with a short postharvest life, mainly due to a rapid lost of firm texture. To control the strawberry fruit softening, we obtained transgenic plants that incorporate an antisense sequence of a strawberry pectate lyase gene under the control of the 35S promoter. Forty-one independent transgenic lines (Apel lines) were obtained, propagated in the greenhouse for agronomical analysis, and compared with control plants, non-transformed plants, and transgenic lines transformed with the pGUSINT plasmid. Total yield was significantly reduced in 33 of the 41 Apel lines. At the stage of full ripen, no differences in color, size, shape, and weight were observed between Apel and control fruit. However, in most of the Apel lines, ripened fruits were significantly firmer than controls. Six Apel lines were selected for further analysis. In all these lines, the pectate lyase gene expression in ripened fruit was 30% lower than in control, being totally suppressed in three of them. Cell wall material isolated from ripened Apel fruit showed a lower degree of in vitro swelling and a lower amount of ionically bound pectins than control fruit. An analysis of firmness at three different stages of fruit development (green, white, and red) showed that the highest reduction of softening in Apel fruit occurred during the transition from the white to the red stage. The postharvest softening of Apel fruit was also diminished. Our results indicate that pectate lyase gene is an excellent candidate for biotechnological improvement of fruit softening in strawberry.     

Effects of ethylene and acetylene on mango fruit ripening

Mangoes (var. Tommy Atkins) were exposed to ethylene and acetylene over a range of concentrations at high humidity for 24 h at 25°C, then ripened in air alone. Ripeness was assessed after 4 and 8 days by analysis of texture, colour development, soluble solids and acid contents. Ethylene in air at concentrations of 0.01 ml litre^-1 and above or acetylene at 1.0 ml litre^-1 were found to initiate ripening. Treatment with 0.01 ml litre^-1 acetylene resulted in limited softening but had no effect on the other ripening changes analysed. Individual ripening processes responded differently to treatment: texture changes were most rapidly affected, while the rate of acidity losses was often reduced in ethylene treated fruits. Acetylene-treated fruits at concentrations of 0.01 and 0.1 ml litre^-1 showed delayed ripening when compared to those treated with either 1.0 ml litre^-1 acetylene or ethylene. Increased acetylene concentrations of 2.0 ml litre^-1 gave a similar response to 1.0 ml litre^-1, although in some instances there were indications of inhibitory effects.     

Clinical evaluation of endocervical prostaglandin E2-triacetin-gel for preinduction cervical softening in pregnant women at term

In an open randomized clinical trial 100 pregnant women with low Bishop Scores at term were treated either with intracervical Prostaglandin (PG) E2 (0.5 mg in 2.5 ml triacetin-gel) 12 hours before labor induction with intravenous oxytocin or with oxytocin infusion alone. In 46 of the 50 pretreated patients (92%) the Bishop Score progressed at least 3 points, in four cases only 2 points. The mean Bishop score in the untreated patients increased insignificantly. After PGE2-gel administration 16 patients delivered during the 12 hour interval compared to 3 in the group without pretreatment. The first induction attempt was successful in 14 (64%) of the 22 patients that were left to be induced after cervical softening and in 26 (57%) of the 47 women without cervical priming. The Cesarean section rate was 10% (n = 5) in the PGE2-gel group and 12% (n = 6) in the control group. Dosage of oxytocin required for labor induction was significantly lower after cervical softening. No serious fetal or maternal side effects were observed after PGE2 pretreatment.     

Effect of dicumarol on the growth of some soil microorganisms.

The effect of dicumarol on growth of selected soil bacteria: Azotobacter chroococcum, Arthrobacter globiformis, A. citreus and Bacillus megaterium was studied. The following minimum concentrations were inhibitory in vitro: Arthrobacter citreus--20 mug/ml., Bacillus megaterium--40 mug/ml., Azotobacter chroococcum--40 mug/ml. Arthrobacter globiformis--70 mug/ml. Cells of all microorganisms studied grown in the presence of dicumarol developed aberrant morphological forms.     

Serial sectioning techniques for a modified LKB Historesin

A glycol methacrylate-based plastic that is capable of producing serial sections has been introduced by LKB. This plastic, provided in the LKB 2218-500 Historesin Embedding Kit, has been tested in our laboratory for its ribbon forming capacity. Various block sizes, concentrations of the softening agent polyethylene glycol 400 (PEG), and tissue types have been examined to determine the optimal conditions for ribbon formation. Although unmodified LKB Historesin is capable of forming ribbons, these ribbons often break. The addition of PEG to the embedding solution enhances ribbon formation. When sectioning with glass knives the best results are achieved with the addition of 0.2 ml of PEG/5.0 ml of embedding medium. A conventional AO rotary microtome can be used to produce ribbons if, in addition to the added PEG (optimal concentration 0.25-0.30 per 5 ml of embedding medium) a thin layer of dental wax is added to the upper and lower surfaces of the block. Ribbons form more easily on microtomes, such as the LKB Historange, that have a retractable specimen arm. If serial sections are to be produced it is very important that the upper and lower faces of blocks be parallel.     

Serial Sectioning Techniques for A Modified LKB Historesin

A glycol methacrylate-based plastic that is capable of producing; serial sections has been introduced by LKB. This plastic, provided in the LKB 2218-500 Historesin Embedding Kit, has been tested in our laboratory for its ribbon forming capacity. Various block sizes, concentrations of the softening agent polyethylene glycol 400 (PEG), and tissue types have been examined to determine the optimal conditions for ribbon formation. Although unmodified LKB Historesin is capable of forming ribbons, these ribbons often break. The addition of PEG to the embedding solution enhances ribbon formation. When sectioning with glass knives the best results are achieved with the addition of 0.2 ml of PEG/5.0 ml of embedding medium. A conventional AO rotary microtome can be used to produce ribbons if, in addition to the added PEG (optimal concentration 0.25-0.30 per 5 ml of embedding medium) a thin layer of dental wax is added to the upper and lower surfaces of the block. Ribbons form more easily on microtomes, such as the LKB Historange, that have a retractable specimen arm. If serial sections are to be produced it is very important that the upper and lower faces of blocks be parallel.     

The Actinomyces of Potato Scab Demonstrated by Fluorescence Microscopy

The potato scab Actinomyces, like other acid-fast organisms, can be selectively impregnated with carbol-auramin and when exposed to ultraviolet radiation fluoresces bright yellow. The marked contrast of the bright yellow filaments permits ready localization and study of the micropathology of the tissue with a simple fluorescence microscope. The staining technic is done at room temperature and no counterstain is used. The fluorescence technic confirms Lutman's conclusion that the filaments are intercellular and grow within the middle lamellae. After complete removal of the paraffin, the sections are stained 4 minutes in carbol-auramin, (distilled water 97 ml., liquified phenol 3 ml., certified auramin 0.1 g.), washed, destained in a 0.5% solution of NaCl in 70% alcohol with 0.5 ml, HCl (conc.) per 100 ml., washed, and mounted in glycerin.     

果实软化的胞壁物质和水解酶变化

果实软化通常被认为是由于胞壁水解酶如多聚半乳糖醛酸酶,果胶酯酶,纤维素酶降解胞壁物质导致。本文概述了这三种酶分子与果实软化关系的研究进展。反义基因证明,这三种酶基因的任一种表达被报制,果实能够正常软化,暗示果实的软化有其它因子的参与。其中由细胞内的淀粉酶和蔗糖酶引起的细胞膨压的变化及果胶的溶解可能是引起果肉软化的重要原因。     

Mineral content of the forearms of babies born to Asian and white mothers.

Vitamin D deficiency is common in pregnant Asian women. The effect of maternal vitamin D deficiency on fetal skeletal mineralisation was assessed by measuring the bone mineral content of babies born to 45 Asian women, 19 Asian women who had received 1000 units of vitamin D during the last trimester, and 12 white women. The mean cord blood concentrations of 25-hydroxy vitamin D in the three groups were 5.9 +/- SE 0.9 nmol/l (2.4 +/- SE 0.4 ng/ml), 15.2 +/- 3.2 nmol/l (6.1 +/- 1.3 ng/ml), and 33.4 +/- 3.6 nmol/l (13.4 ng/ml), respectively. Despite this wide variation in values there was no significant difference in the bone mineral content (as assessed by photon absorptiometry) of the forearms of babies born to these women. This suggests that mineralization of the fetal skeleton is not impaired in maternal vitamin D deficiency. Craniotabes (skull softening) was present in seven of the 64 Asian babies. The bone mineral content in these babies was not significantly different from that of babies without this sign, and craniotabes should not therefore be taken as an indication of a generalized impairment in skeletal mineralization.     

Exercise stroke volume relative to plasma-volume expansion

The effects of plasma-volume (PV) expansion on stroke volume (SV) (CO2 rebreathing) during submaximal exercise were determined. Intravenous infusion of 403 +/- 21 ml of a 6% dextran solution before exercise in the upright position increased SV 11% (i.e., 130 +/- 6 to 144 +/- 5 ml; P less than 0.05) in untrained males (n = 7). Further PV expansion (i.e., 706 +/- 43 ml) did not result in a further increase in SV (i.e., 145 +/- 4 ml). SV was somewhat higher during supine compared with upright exercise when blood volume (BV) was normal (i.e., 138 +/- 8 vs. 130 +/- 6 ml; P = 0.08). PV expansion also increased SV during exercise in the supine position (i.e., 138 +/- 8 to 150 +/- 8 ml; P less than 0.05). In contrast to these observations in untrained men, PV expansion of endurance-trained men (n = 10), who were naturally PV expanded, did not increase SV during exercise in the upright or supine positions. When BV in the untrained men was increased to match that of the endurance-trained subjects, SV was observed to be 15% higher (165 +/- 7 vs. 144 +/- 5 ml; P less than 0.05), whereas mean blood pressure and total peripheral resistance were significantly lower (P less than 0.05) in the trained compared with untrained subjects during upright exercise at a similar heart rate. The present findings indicate that exercise SV in untrained men is preload dependent and that increases in exercise SV occur in response to the first 400 ml of PV expansion. It appears that approximately one-half of the difference in SV normally observed between untrained and highly endurance-trained men during upright exercise is due to a suboptimal BV in the untrained men.