Formation of ion-pairs in aqueous solutions of diclofenac salts

In this work we studied the ability of the diclofenac anion to form ion-pairs in aqueous solution in the presence of organic and inorganic cations: ion-pairs have a polarity and hydrophobicity more suitable to the partition than each ion considered separately and can be extracted by a lipid phase. The cations considered were those of the organic bases diethylamine, diethanolamine, pyrrolidine, N-(2-hydroxyethyl) pyrrolidine and N-(2-hydroxyethyl) piperidine; the inorganic cations studied were Li(+), Na(+), K(+), Rb(+), Cs(+). Related to each cation we determined the equilibrium constant (K(XD)) for the ion-pair formation with the diclofenac anion in aqueous solution and the water/n-octanol partition coefficient (P(XD)) for each type of ion-pair formed. Among the alkali metal cations, only Li(+) shows some interaction with the diclofenac anion, in agreement with its physiological behaviour of increasing clearance during the administration of diclofenac. The influence of the ionic radius and desolvation enthalpy of the alkali metal cations on the ion-pair formation and partition was briefly discussed. Organic cations promote the formation of ion-pairs with the diclofenac anion better than the inorganic ones, and improve the partition of the ion-pair according to their hydrophobicity. The values of the equilibrium parameters for the formation and partition of ion-pairs are not high enough to allow the direct detection of their presence in the aqueous solution. Their formation can be appreciated in the presence of a lipid phase that continuously extracts the ion-pair. Extraction constants (E(XD)=P(XD) times K(XD)) increase passing from inorga to organic cations. This study could help to clarify the mechanism of the percutaneous absorption of diclofenac in the form of a salt, a route where the formation of ion-pairs appears to play an important role.

[Cryptococcal lymphadenitis in a dog.]

We describe a case of canine crytococcosis, the clinical symptoms were: feverish syndrome, vomiting and diarrhoeas and bilateral lymphadenitis in superficial lymph nodes. Microbiology and histopathology study of popliteal lymph node biopsy demonstrated the presence of round yeasts of some 3 microm of diameter, which we identified as Cryptococcus neoformans. Thirty months after suspending the medication the dog returned to the surgery; the dog was very thin and it had nervous symptoms; the owners decided it upon euthanasia. After carrying out the necropsy we take samples for their microbiology and histopathology study, both techniques detect to C. neoformans in marrow, CNS tissue and lymph nodes.

Noninvasive assessment of left atrial maximum dP/dt by a combination of transmitral and pulmonary venous flow

OBJECTIVES

The study assessed whether hemodynamic parameters of left atrial (LA) systolic function could be estimated noninvasively using Doppler echocardiography.

BACKGROUND

Left atrial systolic function is an important aspect of cardiac function. Doppler echocardiography can measure changes in LA volume, but has not been shown to relate to hemodynamic parameters such as the maximal value of the first derivative of the pressure (LA dP/dt(max)).

METHODS

Eighteen patients in sinus rhythm were studied immediately before and after open heart surgery using simultaneous LA pressure measurements and intraoperative transesophageal echocardiography. Left atrial pressure was measured with a micromanometer catheter, and LA dP/dt(max) during atrial contraction was obtained. Transmitral and pulmonary venous flow were recorded by pulsed Doppler echocardiography. Peak velocity, and mean acceleration and deceleration, and the time-velocity integral of each flow during atrial contraction was measured. The initial eight patients served as the study group to derive a multilinear regression equation to estimate LA dP/dt(max) from Doppler parameters, and the latter 10 patients served as the test group to validate the equation. A previously validated numeric model was used to confirm these results.

RESULTS

In the study group, LA dP/dt(max) showed a linear relation with LA pressure before atrial contraction (r = 0.80, p < 0.005), confirming the presence of the Frank-Starling mechanism in the LA. Among transmitral flow parameters, mean acceleration showed the strongest correlation with LA dP/dt(max) (r = 0.78, p < 0.001). Among pulmonary venous flow parameters, no single parameter was sufficient to estimate LA dP/dt(max) with an r2 > 0.30. By stepwise and multiple linear regression analysis, LA dP/dt(max) was best described as follows: LA dP/dt(max) = 0.1 M-AC +/- 1.8 P-V - 4.1; r = 0.88, p < 0.0001, where M-AC is the mean acceleration of transmitral flow and P-V is the peak velocity of pulmonary venous flow during atrial contraction. This equation was tested in the latter 10 patients of the test group. Predicted and measured LA dP/dt(max) correlated well (r = 0.90, p < 0.0001). Numerical simulation verified that this relationship held across a wide range of atrial elastance, ventricular relaxation and systolic function, with LA dP/dt(max) predicted by the above equation with r = 0.94.

CONCLUSIONS

A combination of transmitral and pulmonary venous flow parameters can provide a hemodynamic assessment of LA systolic function.

Assessment of diastolic function by tissue Doppler echocardiography: comparison with standard transmitral and pulmonary venous flow

The objective of this study was to determine the utility of Doppler tissue echocardiography in the evaluation of diastolic filling and in discriminating between normal subjects and those with various stages of diastolic dysfunction. We measured myocardial velocities in 51 patients with various stages of diastolic dysfunction and in 27 normal volunteers. The discriminating power of each of the standard Doppler indexes of left ventricular filling, pulmonary venous flow, and myocardial velocities was determined with the use of Spearman rank correlation and analysis of variance F statistics. Early diastolic myocardial velocity (E(m)) was higher in normal subjects (16.0 +/- 3.8 cm/s) than in patients with either delayed relaxation (n = 15, 7.5 +/- 2.2 cm/s), pseudonormal filling (n = 26, 7.6 +/- 2.3 cm/s), or restrictive filling (n = 10, 7.4 +/- 2.4 cm/s, P <.0001). E(m ) was the best single discriminator between control subjects and patients with diastolic dysfunction (P =.7, F = 64.5). Myocardial velocities assessed by Doppler tissue echocardiography are useful in differentiating patients with normal from those with abnormal diastolic function. Myocardial velocity remains reduced even in those stages of diastolic dysfunction characterized by increased preload compensation.

Description and preliminary evaluation of a new ultrasonic atomizer for spray-congealing processes

A new atomizer that operates with ultrasonic energy is described. This apparatus is intended to obtain microparticulate drug delivery systems through spray-congealing or spray-drying technologies. In this work, some experimental results are reported on model systems submitted to spray-congealing. The formulations under examination contained theophylline and fenbufen as model drugs and stearic acid, carnauba wax, Cutina HR(R) and Compritol 888 ATO(R) as low melting excipients. Non-aggregate and spherical-shaped microparticles were obtained with all the materials tested; moreover, they had smooth surface and good flowability. The particle sizes depend on the amount of drug present and in each case the maximum size value of the distribution frequency was found to be 375 mu. In vitro release of the drug depends on its solubility and on the excipient lipophilicity. The results suggest that the ultrasound-assisted atomizer could be proposed as a possible alternative to traditional atomizers used for spray-congealing in the pharmaceutical field.

Effects of ultrasound-assisted compaction on Ketoprofen/Eudragit S100 mixtures

Ketoprofen alone and in binary mixtures with Eudragit S100 was compacted by an ultrasound-assisted (US) tableting machine at an energy ranging from 50 to 400 J. The final material was analysed by TLC and HPLC: no decomposition product of the active agent was found. IR spectra and HSM revealed the absence of any interaction between the two components. Thermal analysis (DSC) evidenced that ketoprofen inside the mixtures was transformed into an amorphous state, documented by the decreasing of the DeltaHfus as the Eudragit/ketoprofen ratio increases and as US energy increases. While pure ketoprofen recovers its crystalline state quickly after the US treatment, the presence of Eudragit was found to slow down or possibly to prevent the regeneration of the crystallinity.

Clinical, virologic, and immunologic follow-up of convalescent Ebola hemorrhagic fever patients and their household contacts, Kikwit, Democratic Republic of the Congo. Commission de Lutte contre les Epidémies à Kikwit

A cohort of convalescent Ebola hemorrhagic fever (EHF) patients and their household contacts (HHCs) were studied prospectively to determine if convalescent body fluids contain Ebola virus and if secondary transmission occurs during convalescence. Twenty-nine EHF convalescents and 152 HHCs were monitored for up to 21 months. Blood specimens were obtained and symptom information was collected from convalescents and their HHCs; other body fluid specimens were also obtained from convalescents. Arthralgias and myalgia were reported significantly more often by convalescents than HHCs. Evidence of Ebola virus was detected by reverse transcription-polymerase chain reaction in semen specimens up to 91 days after disease onset; however, these and all other non-blood body fluids tested negative by virus isolation. Among 81 initially antibody negative HHCs, none became antibody positive. Blood specimens of 5 HHCs not identified as EHF patients were initially antibody positive. No direct evidence of convalescent-to-HHC transmission of EHF was found, although the semen of convalescents may be infectious. The existence of initially antibody-positive HHCs suggests that mild cases of Ebola virus infection occurred and that the full extent of the EHF epidemic was probably underestimated.

A new simple method to perform pressure-volume curves obtained under quasi-static conditions during mechanical ventilation

OBJECTIVE

To describe a fast, simple method to acquire pressure-volume curves of the respiratory system and to compare this with a classic method in terms of reliability of the data and speed.

DESIGN

Acquisition of pressure-volume curves by low flow inflation technique (P-Vlf) versus the occlusion technique (P-Vst) using the standard equipment of a Cesar ventilator.

SETTING

General ICU - Aix en Provence Hospital.

PATIENTS

Ten sedated, curarized patients undergoing mechanical ventilation.

INTERVENTIONS

P-Vlf curves were acquired by setting the ventilator parameters at f = 5 c./min, duty time Ti/Ttot = 80 %, VT = 1100 ml, pause time = 0. The pressure and volume data were collected directly on the ventilator screen. P-Vst curves were acquired using an airway occlusion technique. The pressures obtained for the same inflation volumes and times necessary for performance of the two techniques were compared.

RESULTS

The time needed to acquire a P-Vlf curve was 3 min versus 38 min for P-Vst curve. Concordance analysis between the two methods showed a 95 % confidence interval of (-0.5 cm H2O, + 1.8 cm H2O) for pressure.

CONCLUSIONS

P-Vlf curves are close to P-Vst curves, are much less time-consuming, easy to acquire with Cesar ventilator equipment, and may be used in clinical routine to assess the elastic properties of the respiratory system.

Aldose reductase catalyzes the oxidation of naphthalene-1, 2-dihydrodiol for the formation of ortho-naphthoquinone

The oxidation of naphthalene-1,2-dihydrodiol (ND) to o-naphthoquinone (NQ) in the lens is believed to be responsible for the formation of cataracts in naphthalene-fed rats. Studies using either recombinant rat lens (RLAR) or human muscle aldose reductase (HMAR) incubated in vitro with ND in the presence of NAD(P) verified that aldose reductase (EC 1.1.1.21) is the dihydrodiol dehydrogenase that catalyzes the oxidation of ND to NQ. Kinetic studies of Vmax/Km indicated that RLAR catalyzes the NAD-dependent oxidation of ND with an optimal pH of 9.0. The corresponding activity of HMAR was lower than that of rat enzyme. The metabolite produced by the incubation of RLAR with ND in the presence of 2-mercaptoethanol and NAD in 20 mM phosphate buffer, pH 7.5, was isolated by C18 reversed-phase high-performance liquid chromatography. The elution profile showed the formation of a new peak that was identical with a peak generated when NQ was incubated under the same condition. The metabolite in both peaks was identified as 4-(2-hydroxyethylsulfanyl)-1, 2-dihydro-1,2-naphthalenedione (HNQ) by 1H and 13C NMR analyses using homonuclear correlation spectroscopy, heteronuclear multiple quantum coherence, and heteronuclear shift correlations via multiple bond connectivities as well as infrared analysis. HNQ is readily autoxidized to 2,3-dihydro-1-oxa-4-thia-9,10-phenanthrenedione. The stoichiometry of 1:1 between the consumption of ND and the formation of NADH for the formation of HNQ implies that rat lens aldose reductase catalyzes a 2e- oxidation of ND to yield the corresponding ketol, which is autoxidized to NQ.

Application of color Doppler flow mapping to calculate orifice area of St Jude mitral valve

BACKGROUND

The effective orifice area (EOA) of a prosthetic valve is superior to transvalvular gradients as a measure of valve function, but measurement of mitral prosthesis EOA has not been reliable.

METHODS AND RESULTS

In vitro flow across St Jude valves was calculated by hemispheric proximal isovelocity surface area (PISA) and segment-of-spheroid (SOS) methods. For steady and pulsatile conditions, PISA and SOS flows correlated with true flow, but SOS and not PISA underestimated flow. These principles were then used intraoperatively to calculate cardiac output and EOA of newly implanted St Jude mitral valves in 36 patients. Cardiac output by PISA agreed closely with thermodilution (r=0.91, Delta=-0.05+/-0.55 L/min), but SOS underestimated it (r=0.82, Delta=-1.33+/-0.73 L/min). Doppler EOAs correlated with Gorlin equation estimates (r=0.75 for PISA and r=0.68 for SOS, P<0.001) but were smaller than corresponding in vitro EOA estimates.

CONCLUSIONS

Proximal flow convergence methods can calculate forward flow and estimate EOA of St Jude mitral valves, which may improve noninvasive assessment of prosthetic mitral valve obstruction.

Three-dimensional echocardiographic planimetry of maximal regurgitant orifice area in myxomatous mitral regurgitation: intraoperative comparison with proximal flow convergence

OBJECTIVES

We sought to validate direct planimetry of mitral regurgitant orifice area from three-dimensional echocardiographic reconstructions.

BACKGROUND

Regurgitant orifice area (ROA) is an important measure of the severity of mitral regurgitation (MR) that up to now has been calculated from hemodynamic data rather than measured directly. We hypothesized that improved spatial resolution of the mitral valve (MV) with three-dimensional (3D) echo might allow accurate planimetry of ROA.

METHODS

We reconstructed the MV using 3D echo with 3 degrees rotational acquisitions (TomTec) using a transesophageal (TEE) multiplane probe in 15 patients undergoing MV repair (age 59 +/- 11 years). One observer reconstructed the prolapsing mitral leaflet in a left atrial plane parallel to the ROA and planimetered the two-dimensional (2D) projection of the maximal ROA. A second observer, blinded to the results of the first, calculated maximal ROA using the proximal convergence method defined as maximal flow rate (2pi(r2)va, where r is the radius of a color alias contour with velocity va) divided by regurgitant peak velocity (obtained by continuous wave [CW] Doppler) and corrected as necessary for proximal flow constraint.

RESULTS

Maximal ROA was 0.79 +/- 0.39 (mean +/- SD) cm2 by 3D and 0.86 +/- 0.42 cm2 by proximal convergence (p = NS). Maximal ROA by 3D echo (y) was highly correlated with the corresponding flow measurement (x) (y = 0.87x + 0.03, r = 0.95, p < 0.001) with close agreement seen (AROA (y - x) = 0.07 +/- 0.12 cm2).

CONCLUSIONS

3D echo imaging of the MV allows direct visualization and planimetry of the ROA in patients with severe MR with good agreement to flow-based proximal convergence measurements.

Effect of sorbitol dehydrogenase inhibition on sugar cataract formation in galactose-fed and diabetic rats

Several recent studies with the sorbitol dehydrogenase inhibitors 4-[4-(N,N-dimethylsulfamoyl)-piperazino]-2-methylpyrimidine, SDH-1, and its active metabolite 4-[4-(N, N-dimethylsulfamoyl)piperazino]-2-hydroxymethylpyrimidine , SDH-2, suggest that inhibition of sorbitol dehydrogenase may be beneficial in delaying the onset of diabetic complications due to their ability to ameliorate redox changes associated with polyol metabolism. To compare the relative importance of sorbitol dehydrogenase versus aldose reductase inhibition on sugar cataract formation, cataract formation was monitored in 50% galactose-fed and diabetic rats treated with/without the sorbitol dehydrogenase inhibitors SDH-1 or SDH-2 or the aldose reductase inhibitors AL 1576 or Ponalrestat. For these studies, diabetes was induced in young 50 g rats with streptozotocin while galactosemia was produced by feeding a diet containing 50% galactose. Inhibitors were administered in the diet with the diet containing 0.06% (w/w) of the sorbitol dehydrogenase inhibitors or Ponalrestat, and 0.0125% (w/w) of AL 1576. Cataract formation was monitored by hand-held slit lamp and polyol levels were measured by gas chromatography. Sugar cataract formation was accelerated in diabetic rats treated with sorbitol dehydrogenase inhibitors while no difference in cataract formation was observed in galactose-fed rats treated with/without SDH inhibitors. Cataract formation was inhibited in both diabetic and galactosemic rats by either Ponalrestat or AL 1576. These results support the concept that sugar cataract formation is initiated by the aldose reductase catalysed intracellular accumulation of polyols and that these sugar cataracts can be prevented through inhibition of aldose reductase.

Validation of the verbal autopsy method to ascertain acute respiratory infection as cause of death

The validity of the Verbal Autopsy (VA) in death due to acute respiratory infection (ARI), was tested in 36 children who died by any acute infectious disease as stated by the necropsy diagnosis, at two public hospitals in Mexico City; the illness started at home. Clinical data obtained through VA were compared with diagnoses of necropsies, which were considered as "gold standard". The presence of dyspnoea for more than one day showed sensitivity of 0.69 and specificity of 0.74, while history of coughing showed a sensitivity of 0.61 and a specificity of 0.73. Combination of both clinical data improved specificity (0.83), but decreased sensitivity (0.54). Additional sources of diagnosis (a panel of assessors, the clinical record and the death certificate), also showed good sensitivity (0.69-0.77) and specificity (0.74-7.8). Focus on history of dyspnea and/or cough in children with an infectious syndrome should be emphasized, as a useful epidemiologic tool to determine children's mortality due to ARI in areas where diagnosis resources are constrained.

Ethnic differences in testicular structure and spermatogenic potential may predispose testes of Asian men to a heightened sensitivity to steroidal contraceptives

Spermatogenesis in Asian men appears to be more susceptible to suppression by steroidal contraceptives administered in clinical trials than spermatogenesis in Caucasian men. The objective of this study was to determine whether ethnic differences exist in testicular structure and spermatogenic potential that might predispose Asians to a high sensitivity to steroidal contraceptives. Testes from 12 Chinese men were compared to those from 8 Hispanic men and 12 non-Hispanic Caucasian men of ages 29+/-3, 30+/-2, and 29+/-3 years, respectively. Testes were fixed by vascular perfusion with glutaraldehyde, further fixed in osmium, embedded in Epon, and evaluated by stereology using 0.5-microm sections stained with toluidine blue. Homogenates of fixed testes were evaluated for the number of Sertoli cells and the daily sperm production based on pachytene primary spermatocytes (PDSP) or spermatids with spherical nuclei (DSP). Paired parenchymal weight was less (P < 0.05) in Chinese men than in Hispanic or Caucasian men. The PDSP per gram of parenchyma was lower (P < 0.05) and the DSP per gram tended to be lower in Chinese men than in other groups. The histologic appearance, volume density, and length per man of seminiferous tubules were the same among the ethnic groups; however, the diameter of seminiferous tubules was less (P < 0.05) in Chinese than in Hispanic or Caucasian men. The PDSP per man and the DSP per man were lower (P < 0.05) in Chinese than in Hispanic or Caucasian men. The number of Sertoli cells per gram was higher (P < 0.05) in Chinese or Caucasian men than in Hispanic men, but the number of Sertoli cells per man was lower (P < 0.05) in Chinese men than in Hispanic or Caucasian men. Sertoli cell function, measured as the number of germ cells accommodated by a single Sertoli cell, was lower (P < 0.05) in Chinese men than in Caucasian men. The volume density of Leydig cell cytoplasm was greatest (P < 0.05) in Chinese men, but the number of Leydig cells was similar among the ethnic groups. Hence, smaller testes coupled with reduced Sertoli cell number and function and reduced daily sperm production could predispose Asian men to have a heightened negative response of testes to steroidal contraceptives, as compared to Caucasian men. Dampening (by exogenous androgens) of any physiological benefit to spermatogenesis that a high volume density of Leydig cell cytoplasm may bestow on the human testis (that Asian men may have evolved to require) would exacerbate ethnic differences in the spermatogenic response to hormonal contraceptives.

Fractal analysis of beta-cyclodextrin-indomethacin particles compacted by ultrasound

An association between indomethacin and beta-cyclodextrin (beta-CD) was obtained by compacting a 1:2 molar physical mixture by ultrasound. The product prepared by this technique was compared with the initial physical mixture and with materials having the same composition but prepared by a simple compaction and kneading process. The samples examined by scanning electron microscopy revealed morphological differences related to the methods of preparation. In particular the material obtained by ultrasound had a smooth surface and on milling produced particles of uniform size; moreover EDAX analysis (energy dispersion analysis by X-rays) also revealed a homogeneous distribution of the two components in each particle examined. Surface fractal dimension of the surface of these particles is very low, suggesting the presence of a regular and smooth surface whereas the sample obtained by kneading had a higher value. The reactive dimension related to dissolution was much higher than the corresponding surface dimension in all cases and had comparable values for all samples regardless of the techniques used. This behavior was attributed to the hydrophilicity of beta-CD, which levels the differences during dissolution and which could be originated by surface imperfections. Experimental results suggested that the material obtained by ultrasound had a dissolution rate comparable to that measured with the kneaded material. The use of ultrasound, however, can both reduce the production time and improve the homogeneity of the association between indomethacin and beta-CD.

Contrasting effects of hypochlorous acid and hydrogen peroxide on endothelial permeability: prevention with cAMP drugs

Activated polymorphonuclear leukocytes generate a cascade of reduced oxygen metabolites. In addition to their antimicrobial role, hydrogen peroxide (H2O2) and hypochlorous acid (HOCl) function as inflammatory mediators and increase the protein permeability of the vascular endothelium. The objectives of the present study were to compare the effects of H2O2 and HOCl with respect to relative potencies and the time course and magnitude of changes in cell shape and permeability of endothelial cell monolayers derived from bovine pulmonary artery, to determine if HOCl produced by conversion of H2O2 with myeloperoxidase and Cl- produces comparable results as the direct administration of HOCl, and to show that adenosine 3',5'-cyclic monophosphate (cAMP)-enhancing agents can prevent the increased endothelial permeability induced by HOCl and H2O2. HOCl given directly or produced by myeloperoxidase, H2O2, and Cl- caused faster and greater changes in cell shape (cell retraction), electrical resistance, and protein permeability (125I-labeled albumin clearance) of endothelial cell monolayers than induced by H2O2. HOCl (10 to 100 microM) induced these changes within 1 to 3 min, whereas H2O2 (50 to 400 microM) required approximately 30 min. 8-Bromo-cAMP prevented the increased endothelial protein permeability induced by HOCl or H2O2, but isoproterenol only prevented the H2O2 response. Thus, HOCl at a much lower concentration caused a faster and greater increase in endothelial permeability in vitro than H2O2, and an increased intracellular level of cAMP prevented the increased permeability induced by either oxidant.

Age-dependent lens changes in galactose-fed dogs

Aldose reductase initiated sugar cataract formation in 9-month old galactose-fed dogs has been documented to progress from an accentuation of lens sutures (1 month after initial feeding) to the appearance of cortical vacuoles (3 months), cortical opacities (4-6 months) and eventually the progressive formation of a clear zone at the cortical equatorial regions of the cataractous lenses (> 12 months). Here, the effect of age on the onset and degree of sugar cataract formation has been investigated in beagles fed a 30% galactose diet starting at 2, 6, and 24 months of age. Cataract formation was monitored by slit lamp and retroillumination microscopy. Compared to 9-month old dogs, cataract formation in the younger dogs was more rapid and the lens changes were more severe. In the 2-month old group of dogs, galactose-feeding resulted in a rapid formation of dense cataracts which began to resorb after 106 days of galactose feeding with only opaque nuclear remnants remaining after eight months. These changes were mirrored by age-dependent reductions of lenticular NADPH-dependent reductase activity.

Purification and characterization of an invertase from Candida utilis: comparison with natural and recombinant yeast invertases

A periplasmic invertase from the yeast Candida utilis was purified to homogeneity from cells fully derepressed for invertase synthesis. The enzyme was purified by successive Sephacryl S-300, and affinity chromatography and shown to be a dimeric glycoprotein composed of two identical monomer subunits with an apparent molecular mass of 150 kDa. After EndoH treatment, the deglycosylated protein showed an apparent molecular weight of 60 kDa. The apparent K(m) values for sucrose and raffinose were 11 and 150 mM, respectively, similar to those reported in Saccharomyces cerevisiae. The range of optimum temperature was 60-75 degrees C. The optimum pH was 5.5 and the enzyme was stable over pH range 3-6.

An index of early left ventricular filling that combined with pulsed Doppler peak E velocity may estimate capillary wedge pressure

OBJECTIVES

This study sought to determine the applicability of the combined information obtained from transmitral Doppler flow and color M-mode Doppler flow propagation velocities for estimating pulmonary capillary wedge pressure.

BACKGROUND

Although Doppler-derived measurements of left ventricular (LV) filling have been applied to determine left atrial pressure, their accuracy has been limited by the variable effect of ventricular relaxation in these indexes. Recently, flow propagation velocity measured by color M-mode Doppler echocardiography has been suggested as an index of ventricular relaxation.

METHODS

We studied 45 patients admitted to the intensive care unit who underwent invasive hemodynamic monitoring. We measured peak early (E) and late (A) transmitral Doppler velocities, E/A ratio and flow propagation velocity (vp) and compared them by linear regression with pulmonary capillary wedge pressure (pw).

RESULTS

We found a modest positive correlation between pw and E (r = 0.62, p < 0.001) and the E/A ratio (r = 0.52, p < 0.001) and a negative correlation between pw and vp (r = -0.34, p = 0.02). By stepwise linear regression, only E and vp were statistically significant predictors of pw. However, the E/vp ratio provided the best estimate of pw (r = 0.80, p < 0.001; pw = 5.27 x [E/vp] + 4.6, SEE 3.1 mm Hg).

CONCLUSIONS

The ratio of component velocity (E) over the color M-mode propagation velocity during early LV filling, by correcting for the effect of LV relaxation, provides a better estimate of pw than standard measurements of transmitral Doppler flow.

Comparison of the usefulness of Doppler pressure half-time in mitral stenosis in patients < 65 and > or = 65 years of age

Doppler pressure half-time is a reliable method for estimating mitral valve area when net left atrial and ventricular compliance remain stable. The accuracy of Doppler pressure half-time in estimating mitral valve area in older patients is unknown. We studied 80 patients (65 women and 15 men, aged 56 +/- 14 years) with cardiac catheterization and echocardiography. Mitral valve area was calculated using the Gorlin formula and by the Doppler pressure half-time method. Patients were stratified into those aged < 65 years (n = 57), and those aged > or = 65 years (n = 23). The discordance between pressure half-time and Gorlin-derived mitral valve area was assessed and related to multiple clinical, echocardiographic, and hemodynamic variables. The difference between pressure half-time and Gorlin-derived mitral valve area was greater in the older than in the younger patient (0.34 +/- 0.30 vs 0.15 +/- 0.27 cm2, p = 0.009) but the older group had smaller mitral valve areas by the Gorlin method (0.72 +/- 0.18 vs 0.89 +/- 0.32 cm2, p = 0.02) and lower cardiac output. The difference between pressure half-time and Gorlin remained greater in the group of older patients (0.32 +/- 0.30 vs 0.19 +/- 0.22 cm2, p = 0.04), even when the analysis was restricted to patients with similar mitral valve area (< 1 cm2 by the Gorlin method). Using multivariate analysis, age > or = 65 years remained the only significant predictor of the discrepancy between pressure half-time and Gorlin mitral valve area. Thus, when compared with Gorlin-derived mitral valve area, pressure half-time overestimated valve area in older patients, and this technique for estimating mitral valve area should be used with caution in patients > or = 65 years of age.

Use of fatty donor liver is associated with diminished early patient and graft survival

It is well known that implantation of donor livers with severe fatty infiltration (>60%) is frequently associated with early hepatic dysfunction and an increased incidence of primary nonfunction after liver transplantation. The outcome of donor livers with less fatty infiltration has not been well defined. We, therefore, studied the outcome of 59 liver transplantations in which donor livers with up to 30% fat were used. Patient outcome was compared to a time-matched control group of 57 patients. The two groups were similar in terms of age, gender, preservation time, primary diagnosis, and UNOS status. We compared both groups with regard to 4-month and 2-year patient and graft survival. We also assessed the incidence of ischemic type biliary strictures and hepatic artery thrombosis, and evaluated the causes of graft loss in both groups. We found that use of donor livers with up to 30% fatty infiltration was associated with a significant decrease in 4-month graft survival (76% vs. 89%, P<0.05) and in 2-year patient survival (77% vs. 91%, P<0.05). Primary nonfunction and primary dysfunction formed the main cause of graft loss and mortality. Multivariate analysis showed that fatty infiltration is an independent predictive factor for outcome after transplantation. We conclude that liver allografts with up to 30% fat lead to diminished outcome after liver transplantation. However, this diminished outcome should be viewed with respect to the increasing mortality on the national waiting list.

Cell adhesion mechanisms: modeling using derivatized beads and sea urchin cell systems

Agarose beads derivatized with amino acids, peptides, carbohydrates and lectins were used to systematically determine what types of molecules, isolated from all others, can make adhesive bonds strong enough to hold cell-like beads together. The results indicated that strong adhesion occurred when at least one of the two members of certain bead pairs was derivatized with molecules that were dimers or trimers but not monomers. Also, beads derivatized with phosphorylated amino acids, but not their non-phosphorylated counterparts, adhered to beads derivatized with positively charged peptides. Adhesion was sensitive to ionic strength and pH of the medium. It was proposed that adhesion occurred between the phosphate groups of the phosphoamino acids and amino and guanidinium groups of the peptides. Cooperative bonding can explain the stability of the adhesion observed in this system. Information gained from the bead modeling work was used to design experiments to examine the role of phosphorylated molecules in modulating adhesion in sea urchin systems. Phosphoamino acids inhibited sperm-egg interaction, but not reaggregation of blastula cells. Inhibitors of alkaline phosphatase, however, did inhibit reaggregation. The results suggest that cell surface phosphorylated molecules may modulate cellular adhesiveness, in some systems promoting, while in others inhibiting adhesion.

Functional conservation of cytosolic proteins required for endosomal vesicle fusion

Recent studies suggest that intracellular membrane traffic relies upon families of related proteins which confer specificity to individual transport reactions but which operate in tandem with a ubiquitous fusogenic complex containing the N-ethylmaleimide-sensitive fusion protein (NSF). The extent to which components of this process are functionally conserved is apparent from the finding that yeast Sec18 protein (Sec18p) can substitute or mammalian NSF in intra-Golgi transport reactions. Here we report that yeast cytosol can support mammalian endosomal vesicle fusion, demonstrating conservation of cytosolic components required for this reaction. Furthermore, under conditions in which the fusion reaction is NSF-dependent we show that yeast Sec18p can functionally substitute for NSF, showing that the yeast protein is capable of catalysing at least two distinct mammalian membrane fusion events. In addition we exploit the complex pattern of sensitivity of the mammalian reaction to N-ethylmaleimide (NEM), coupled with the use of yeast cytosol, to dissect a number of factors required for fusion. We reveal at least three novel NEM-sensitive activities. One of these can be restored by yeast cytosol suggesting that it is functionally conserved.

Myocardial wall velocity assessment by pulsed Doppler tissue imaging: characteristic findings in normal subjects

To validate the use of pulsed Doppler tissue imaging that measures myocardial wall velocities and to define the characteristics of these velocities in normal subjects, we obtained and compared the anteroseptal and posterior wall velocities in 24 volunteers with pulsed Doppler tissue imaging and digitized M-mode echocardiography. We also studied the relation between velocity components and hemodynamic events timed by standard Doppler flows. There was an excellent correlation between Doppler and M-mode-derived velocities (r = 0.95, p < 0.001), with higher reproducibility for Doppler (r = 0.99) than for M-mode (r = 0.95, p < 0.001). Biphasic velocities that were uniformly present during isovolumic contraction and relaxation were attributed to geometric changes due to asynchronous contraction and ventricular interdependence. We conclude that wall velocities obtained by pulsed Doppler tissue imaging are accurate and reproducible. This method may prove useful for studying the contractile and elastic properties of the myocardium.

Invertase secretion in Hansenula polymorpha under the AOX1 promoter from Pichia pastoris

A DNA fragment containing a transcription regulating region of the alcohol oxidase (AOX1) gene from the methylotrophic yeast Pichia pastoris was used in the construction of a vector for the expression of heterologous proteins in the methylotrophic yeast Hansenula polymorpha. We used this vector to clone the SUC2 gene from Saccharomyces cerevisiae into H. polymorpha yeast. The culture conditions for invertase production using a fed-batch culture were studied. More than 1.5 x 10(3) U/ml of biologically active invertase (1 g/l) were secreted to the cellular periplasmic space. The fermentative process was scaled up to 50 l. Invertase produced from H. polymorpha was glycosylated, but it contained significantly less carbohydrate than protein produced by S. cerevisiae. Using the Western-blot technique, it was observed that invertase secreted from H. polymorpha and invertase secreted from S. cerevisiae showed common antigenic determinants.

Epidemiology of gastric non-Hodgkin's lymphoma patients: parallels with Helicobacter pylori

BACKGROUND

The incidence of gastric non-Hodgkin's lymphoma (NHL) is increasing in the United States. However, little is known about the etiology of the disease. Some studies have shown an association between gastric NHL and Helicobacter pylori. No study has specifically delineated demographic features that distinguish gastric NHL patients from nongastric NHL patients.

MATERIALS AND METHODS

To obtain information about the differences between gastric and nongastric NHL patients, we conducted a hospital chart review study. We examined charts of all 25 cases of primary gastric NHL, as well as charts of 75 randomly selected nongastric NHL patients as controls. All patients were seen in the Division of Oncology at Stanford University Medical Center from 1972 to 1991. Demographic information was tabulated, and differences between the cases and controls were noted. The identified risk factors were determined by both univariate and logistic regression analyses.

RESULTS

There was no difference between gastric NHL cases and nongastric controls with respect to age, gender, race, and family history of any cancer. However, in logistical regression, persons with gastric NHL were more likely than those with other forms of NHL to be born outside the United States (odds ratio = 12.8; 95% confidence interval = 2.9-56.0) and also to have a family history of stomach cancer (odds ratio = 18.4; 95% confidence interval 2.1-160.1).

CONCLUSIONS

Gastric NHL is more likely than NHL at other sites to occur in persons with a family history of gastric cancer or in those born in developing countries. This epidemiological pattern supports the identified role of H. pylori in the development of gastric lymphoma.

Vesicular stomatitis New Jersey virus RNA persists in cattle following convalescence

To test the hypothesis that vesicular stomatitis New Jersey virus (VSV-NJ) persists in convalescent cattle, we used explant cultures and reverse transcription nested polymerase chain reactions to probe for viral genomic, replicative intermediate, and mRNA in two cows experimentally inoculated in the tongue 5 months earlier and three cows naturally infected 4-14 months previously. Virus was not isolated from any tissues of any animal. Sequences of the viral polymerase and nucleocapsid genes were consistently identified in the tongue and lymph nodes draining the tongue of both experimentally infected animals but not in the three naturally infected animals. Replicative intermediate but not messenger RNA sequences were detected. These results showed for the first time the long term persistence of VSV-NJ RNA in its bovine host.

Assessment of mitral annular dynamics during diastole by Doppler tissue imaging: comparison with mitral Doppler inflow in subjects without heart disease and in patients with left ventricular hypertrophy

The purpose of this study was to determine the normal pattern and magnitude of mitral annular velocities in diastole by Doppler tissue imaging (DTI) and to assess whether this is altered in patients with left ventricular hypertrophy. Mitral annulus velocities were measured by DTI. Peak and time-velocity integral were measured from the DTI tracings and the timing of the velocities in relation to electrocardiogram. DTI was compared with M-mode echo of the annulus and mitral inflow Doppler velocities. Integrated annular velocities by DTI correlated with the annular displacement. Early diastolic velocities decreased with age and in patients with left ventricular hypertrophy. In the hypertrophy group, early diastolic velocities were significantly lower than normal even after correcting for age. Patients with left ventricular hypertrophy also showed a delay in peak early diastolic mitral annular velocity (5.5 +/- 21 msec after the E wave). In conclusion, mitral annular velocity in diastole is readily recorded by DTI. The magnitude and the pattern of these velocities are significantly altered by age and by left ventricular hypertrophy. This method provides a new insight into diastolic filling events and may prove useful in detecting abnormal diastolic function.

The hyperphagic effect of 3 alpha-hydroxylated pregnane steroids in male rats

Like benzodiazepines receptor (BDZR) ligands, 3 alpha-hydroxylated, 5 alpha, or 5 beta pregnane steroids are sedative, anticonvulsant, and anxiolytic. BDZR ligands also modulate the feeding response. Therefore, in this study we have investigated the effects of four 3 alpha-hydroxylated pregnane steroids-Pregnanolone (3 alpha-hydroxy-5 beta-pregnan-20-one), allopregnanolone (3 alpha-hydroxy-5 alpha-pregnan-20-one), alphaxalone (3 alpha-hydroxy-5 alpha-pregnan-11,20-dione), and 5 beta-pregnanediol (5 beta-pregnan-3 alpha,20 alpha-diol) on food intake. In non-food deprived male rats, all four steroids increased the consumption of a palatable diet. For pregnanolone (1-10 mg/kg), hyperphagia was found at lower doses than its anxiolytic effect (5-10 mg/kg) as determined using the elevated plus maze test. The presumed steroid antagonists, isopregnanolone (3 beta-hydroxy-5 alpha-pregnan-20-one) (10 mg/kg) and pregnenolone sulfate (2 mg/kg), and the BDZ antagonist, Ro15-1788 (20 mg/kg), did not reverse the hyperphagic effect of pregnanolone. Picrotoxin, a GABAA receptor antagonist, dose dependently and at a subconvulsive dose (1.5 mg/kg), reversed the hyperphagic effect of pregnanolone and alphaxalone, but had no effect on allopregnanolone- and 5 beta-pregnanediol-induced hyperphagia. These results indicate that the hyperphagic effects of pregnanolone and alphaxalone are mediated by the GABAA receptor but not by direct interaction with BDZ receptors. However, allopregnanolone- and 5 beta-pregnanediol-induced hyperphagia may be mediated by other receptor systems. Because some 3 alpha-hydroxylated pregnane steroids are endogenous progesterone metabolites, they may play an important role in appetite control.

Pulmonary vein thrombosis and peripheral embolization

A 78-year-old-woman was admitted to the hospital with bilateral femoral arterial occlusion. Her medical history disclosed atrial fibrillation and a left thoracoplasty performed 50 years earlier for treatment of tuberculosis. A transesophageal echocardiogram demonstrated intraluminal thrombus in a left pulmonary vein. The patient recovered after thromboembolectomy. This case documents another uncommon cause of cardiac thromboembolism in which a transesophageal echocardiogram was essential to make the diagnosis.

Differentiation of constrictive pericarditis from restrictive cardiomyopathy: assessment of left ventricular diastolic velocities in longitudinal axis by Doppler tissue imaging

OBJECTIVES

We sought to determine the utility of left ventricular expansion velocities in differentiating constrictive pericarditis from restrictive cardiomyopathy.

BACKGROUND

Several studies have shown that left ventricular diastolic expansion is influenced by the elastic recoil forces of the myocardium. These forces are affected by intrinsic myocardial disease but should be preserved when diastole is impaired as a result of extrinsic causes.

METHODS

Using Doppler tissue imaging, we measured peak early velocity of longitudinal axis expansion (Ea) in 8 patients with constrictive pericarditis, 7 patients with restriction and 15 normal volunteers. Transmitral early (E) and late (A) Doppler flow velocities, left ventricular systolic and diastolic volumes, ejection fraction and mitral annular M-mode displacement were also compared between the groups.

RESULTS

The Ea value was significantly higher in normal subjects (14.5 +/- 4.7 cm/s [mean +/- SD]) and in patients with constriction (14.8 +/- 4.8 cm/s) than in those with restriction (5.1 +/- 1.4 cm/s, p < 0.001 constriction vs. restriction). There was weak correlation between Ea and the extent of annular displacement (r = 0.55, p = 0.004) and the E/A ratio (r = 0.44, p = 0.03). There was no correlation between Ea and E (r = 0.33, p = 0.07) or ejection fraction (r = 0.21, p = 0.26). By multivariate analysis, Ea was the best variable for differentiating constriction from restriction.

CONCLUSIONS

Our study indicates that longitudinal axis expansion velocities are markedly reduced in patients with restrictive cardiomyopathy. The poor correlation found with transvalvular flow velocities suggests that Ea may be relatively preload independent. The measurement of longitudinal axis expansion velocities provides a clinically useful distinction between constrictive pericarditis and restrictive cardiomyopathy and may prove to be valuable in the study of diastolic function.

Immunogenicity and immunosensitivity of ex vivo human carcinomas: interferon gamma and tumour necrosis factor alpha treatment of tumour cells potentiates their interaction with autologous blood lymphocytes

Human carcinoma cells vary appreciably in the expression of MHC class I, class II, ICAM-1 (CD54) and B7 (CD80) molecules. Short-term in vitro exposure of ex vivo carcinoma cells to interferon gamma and tumour necrosis factor alpha elevated/induced the surface expression of MHC class I, class II and ICAM-1, but only rarely of B7. We found that cytokine treatment elevated the cytotoxic susceptibility and the stimulatory potential of ex vivo tumour cells. This was demonstrated (a) by the increased frequency and elevated level of auto-tumour lysis and (b) by induction of DNA synthesis and generation of cytotoxic lymphocytes in autologous mixed lymphocyte/tumour cell culture (MLTC). The MHC class I and ICAM-1 molecules on the tumour cells were required for interaction with the lymphocytes as indicated by the inhibitory effect of specific mAb both in the stimulation and in the cytotoxic tests. While the cytokine-induced increases in MHC and ICAM-1 on the low-expression tumours were probably important for the modification of functional interaction with the autologous lymphocytes, it is likely that alterations in other properties of tumour cells were also induced which contributed to the phenomenon. This was indicated by the results obtained with several tumours, which expressed indigenously high levels of these molecules but activated the autologous lymphocytes only after cytokine treatment. In several experiments the untreated targets that did not activate the lymphocytes were sensitive to the cytotoxicity of the effectors activated in MLTC. The results show that the afferent and efferent arms of the immune response have different requirements for functional interactions between lymphocytes and tumour cells.

Identification of an aldose reductase inhibitor site by affinity labeling

Animal studies indicate that aldose reductase inhibitors represent a pharmacological method for inhibiting the onset of diabetic complications that is independent of blood sugar control. This has spurred the development of aldose reductase inhibitors (ARIs). To facilitate the rational development of more potent and direct ARIs, more specific knowledge of the structural and pharmacophoric requirements of the site at which ARIs interact are required. Co-crystallization of human placental aldose reductase with the inhibitor zopolrestat has been reported to result in a complex where the inhibitor is almost completely sequestered in the hydrophobic pocket which forms the substrate site. Zopolrestat's observed location, which makes the active site pocket inaccessible to solvent or further productive binding of substrate, is not supported by published inhibitor structure-activity relationships (SAR) studies or kinetic results which indicate that aldose reductase inhibitors such as zopolrestat are either non-competitive or uncompetitive inhibitors. Using a 5-iodoacetamido analog of alrestatin as an affinity labeled aldose reductase inhibitor, an inhibitor binding site on aldose reductase has been located. This inhibitor binding site contains a number of pharmacophoric elements previously proposed for the inhibitor site. Its location and composition is consistent with reported kinetic data, SAR observations, stereochemical requirements, and quantum chemical calculations.

Phase II study of accelerated fractionation radiation therapy with carboplatin followed by vincristine chemotherapy for the treatment of glioblastoma multiforme

PURPOSE

To conduct a Phase II one-arm study to evaluate the long-term efficacy and safety of accelerated fractionated radiotherapy combined with intravenous carboplatin for patients with previously untreated glioblastoma multiforme tumors.

METHODS AND MATERIALS

Between 1988 and 1992, 83 patients received 1.9-2.0 Gy radiation three times a day with 2-h infusions of 33 mg/m2 carboplatin for two 5-day cycles separated by 2 weeks; following radiotherapy, patients received procarbazine, lomustine (CCNU), and vincristine (PCV) for 1 year or until tumor progressed.

RESULTS

Eighty-three patients were evaluable for analysis. Seventy-four of the 83 patients (89%) received one or more courses of PCV; their median survival was 55 weeks. Total resection was performed in 20% (15 of 74), subtotal resection in 69% (51 of 74), and biopsy in 11% (8 of 74); reoperation (total or subtotal resection) was performed in 28 patients (37%). Survival was worst for those > or = 61 year old (median 35 weeks). Fits of the Cox proportional hazards regression model showed covariates individually predictive of improved survival were younger age (p < 0.01), smaller log of radiation volume (p = 0.008), total or subtotal resection vs. biopsy (p = 0.056), and higher Karnofsky performance status (p = 0.055). A multivariate analysis showed that age (p = 0.013) and extent of initial surgery (p = 0.003) together were predictive of a better survival with no other variables providing additional significance. Only 8.4% (7 of 83) of patients had clinically documented therapy-associated neurotoxicity ("radiation necrosis").

CONCLUSION

When comparable selection criteria were applied, the survival in this study is similar to the results currently attainable with other chemoradiation approaches. The relative safety of accelerated fractionated radiotherapy, as used in this study with carboplatin, enables concomitant full-dose administration of chemotherapy or radiosensitizing agents in glioblastoma multiforme patients.

Initial experience with the Cosgrove-Edwards Annuloplasty System

BACKGROUND

The mitral valve has a nonplanar shape and a sphincter action. Pathologic dilatation occurs along the posterior annulus. To preserve the physiologic function and correct annular dilatation, we developed an annuloplasty system that is universally flexible and produces a measured plication of the posterior annulus (Cosgrove-Edwards Annuloplasty System).

METHODS

The results of 150 consecutive mitral valve repairs using this system were analyzed. Mean age was 58 +/- 13 years; 59% were men. The cause of the valve disease was degenerative in 75% of the patients, rheumatic in 13%, ischemic in 8%, and infectious in 4%. Associated procedures were performed in 61 patients (41%).

RESULTS

Echocardiographic mitral regurgitation decreased from 3.7 +/- 0.6 before repair to 0.2 +/- 0.4 after repair (p < 0.0001). There were no hospital deaths and no cases of hemodynamically significant systolic anterior motion or other annuloplasty-related complications. Follow-up was 100% complete at a mean of 3.1 +/- 3.6 months. There were three late deaths, three transient ischemic attacks, and one episode of endocarditis. Five patients (3.3%) have undergone reoperation for recurrent mitral insufficiency; no reoperations were related to the annuloplasty system. At a mean of 9 months, three-dimensional reconstruction of the mitral annulus from multiple echocardiographic images confirmed the nonplanar shape and sphincter mechanism of the annulus. Annular orifice area decreased 19% during the cardiac cycle from a mean of 10.3 cm2 in diastole to 8.6 cm2 in systole.

CONCLUSIONS

This annuloplasty system is effective for repair of insufficiency secondary to all causes, preserves physiologic annulus function, and is associated with a low incidence of valve-related complication.

[MHC-dependent molecular mechanisms of susceptibility and protection in type I diabetes in Mexicans]

MHC class II genes play an important role in the autoimmune destruction of the pancreatic b-cell occurring in IDDM. The genetic pattern of the disease was investigated in Mexican Mestizos. The serological findings of HLA antigens showed a significant association of DR3, DR4, DQ2 and DQ8 and a protective effect of DR11, DR15, DQ5, DQ6 and DQ7. With these results, DNA analysis of HLA-DRB1, B3, B4, DQA1, DQB1, DPA1, DPB1 genes was performed using PCR with allele specific oligotyping. Among the patients, 92.78 carry DQA1 alleles that have ARG in position 52 of DQa chain, and 78.2% are ASP- in DQ5-57. The RR for homozygotes is 32.8 and 5.6, respectively. The main haplotype involved is DRB1*0405, DQA1*0301, DQB1*0302. Thus, DQa and DQb form a relevant recognition site for the "diabetogenic peptidett which induces the autoimmune destruction. Positions 57 and 74 of DRB1 locus contribute highly to the expression and severity of IDDM in Mestizos and other ethnic groups, but not in Caucasians or Blacks.