Hemodynamic changes across the human ductus venosus: a comparison between clinical findings and mathematical calculations.

We investigated the hemodynamics of the ductus venosus in the human fetus by means of a combined approach based on Doppler and computational techniques. The aim of our study was to assess the blood velocity changes across the ductus venosus. Color Doppler equipment was used to investigate 29 normal fetuses between 20 and 39 weeks of gestation. Velocities at the systolic peak (S), diastolic peak (D) and atrial contraction (A) were measured at the isthmus and at the outlet of the ductus venosus, and the corresponding angle-independent indices (S/A, (S-A)/S, (S-A)/D) were calculated. A parametric computational model was developed in order to investigate the influence of anatomical features of the ductus venosus on the hemodynamics of the vessel. In all the fetuses the S, D and A velocities at the outlet portion were significantly lower than those at the isthmic part of the ductus venosus (p < 0.0001). The mean percentages of velocity reduction were 23.1%, 26.5% and 33.6%, respectively. Computational simulations also showed a relevant decrease of the velocity along the ductus venosus during the whole cardiac cycle. Velocity reduction along the ductus was mainly due to its conicity and this reduction generally caused velocity values at the outlet to be below the normal range. Conversely, angle-independent indices measured both at the isthmus and at the outlet lay within the same range of the reported reference values and therefore were not influenced by sampling site.

Deposition of kappa and lambda light chains in amyloid filaments of dialysis-related amyloidosis.

beta 2-Microglobulin (beta 2m) is considered to be the amyloidogenic precursor in dialysis-related amyloidosis, although the implication of other relevant cofactors in the pathogenesis of this disease has also been hypothesized. It is conceivable that substances found in amyloid deposits might represent something more than simple codeposition, possibly playing a pathogenic role in amyloidogenesis. Along these lines, a detailed analysis of the protein composition of amyloid fibrils purified from synovial material surgically obtained from nine patients on long-term dialysis was carried out. By the use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, several other protein components, in addition to beta 2m, were found. These were characterized by NH2 amino-terminal sequencing and immunoblotting. In fibrils obtained by water extraction, which fulfill the electron microscopy criteria of highly pure amyloid material, polyclonal kappa and lambda light chains were detected with a concentration of 15 micrograms/mL in the water extraction material; the beta 2m concentration was 200 micrograms/mL. Light microscopy immunohistochemistry was performed on samples from five patients. Amyloid deposits reacted with anti-beta 2m, and anti-light (kappa, lambda), chain antibodies. The immunoreaction of amyloid filaments to anti-beta 2m, anti-lambda, and anti-kappa light chain antibodies was also tested by electron microscopy by use of the immunogold staining procedure. Amyloid filaments were labeled by the three antibodies and showed a different intensity of immunostaining apparently related to their different aggregation pattern. These observations demonstrate that polyclonal immunoglobulin light chains (kappa and lambda) are not contaminants but, together with beta 2m, represent a major constituent of amyloid deposits in dialysis-related osteoarticular amyloidosis, thus indicating their possible role in amyloidogenesis.

Alpha 2-adrenergic receptor sensitivity in panic disorder: I. GH response to GHRH and clonidine stimulation in panic disorder.

Baseline levels of GH and somatomedin C (SmC) and GH responses to GHRH (1 microgram/kg b.w.) and to clonidine (150 micrograms) were measured in 10 outpatients with panic disorder before and after 30 days of 2-2.5 mg of alprazolam therapy, and in 10 psychophysically healthy controls. Basal levels of GH were normal in the patients and those of SmC significantly elevated, both before and after therapy. Basal GH responses to GHRH stimulation were normal and did not change change after alprazolam treatment. Basal GH responses to clonidine stimulation were blunted in the patients and improved after therapy, in parallel with an amelioration of the psychopathology. Our data suggest that adrenoceptor sensitivity, investigated by the clonidine test, is reduced in panic disorder.

Carbon dioxide/oxygen challenge test in panic disorder.

The effects of a single inhalation of a 35% CO2/65% O2 gas mixture were examined in 71 patients with panic disorder with or without agoraphobia and 44 normal control subjects. Compared with the placebo condition, inhalation of air, the CO2/O2 mixture elicited a clear anxiety reaction only in panic disorder patients, who experienced a sudden rise of subjective anxiety as well as of several panic symptoms. Respiratory symptoms and the fear of dying best distinguished the patients from the control subjects. Baseline anxiety was not the key factor in explaining this differential reaction. The clinical features of panic disorder (namely, frequency of panic attacks, agoraphobia, anticipatory anxiety, and duration of illness) were not significantly related to the response to the challenge test, suggesting that CO2 reactivity might be a trait marker of panic disorder.

Intact renal albumin downregulates the extracellular matrix expression by mesangial cells and renal fibroblasts in vitro.

Chronic Adriamycin (ADR) nephropathy is invariably associated with glomerulosclerosis and tubulointerstitial fibrosis. To investigate the hypothesis that severe albuminuria plays a role in the pathogenesis of both processes, we purified the protein from conditioned media of rats with advanced ADR nephropathy and tested the fibrogenic effect on renal fibroblasts and mesangial cells in vitro. Albumin was purified by pseudoligand chromatography and was identified on the basis of the NH2 amino terminus. Furthermore, it was differentiated from the urinary homologue, being more anionic and more fatted while maintaining a conserved peptide composition. The exposure of renal cells to renal albumin induced a dose-dependent reduction in collagen synthesis with a half-maximal decrease with 0.2 microgram/ml of albumin. With renal albumin levels of 0.4 microgram/ml the collagen incorporation of 3H-proline by mesangial cells and renal fibroblasts (primary cultures and cell lines) was reduced by 76, 81 and 45% respectively. A qualitative analysis by SDS-polyacrylamide electrophoresis and immunoprecipitation of radiolabelled collagens demonstrated a drastic and unselective decrease in all major collagens synthesized by mesangial cells and fibroblasts, including type I, III and V. Previous immunoprecipitation of the protein with anti-rat albumin antibodies completely reversed this phenomenon. Finally, albumin purified from urines of rats with ADR nephropathy downregulated the synthesis by renal cells of the same collagens but this effect was less evident compared to renal albumin. These findings demonstrate that renal albumin drastically reduces the synthesis of collagens by mesangial cells and renal fibroblasts, this effect being most evident on those components which constitute the extracellular matrix in glomerulosclerosis and interstitial fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Lymphocyte cholecystokinin concentrations in panic disorder.

Since cholecystokinin (CCK) is known to be anxiogenic in experimental animals and to induce panic attacks in humans, lymphocyte CCK-8 concentrations were measured in 15 patients with panic disorder and 15 age- and sex-matched healthy subjects. The patients' levels were measured again after a 30-day course of alprazolam therapy, 1.5 mg/day. The CCK-8 concentrations were significantly lower in the patients than in the control subjects and did not change after alprazolam therapy. There was no correlation between the peptide values and levels of anxiety or frequency and severity of panic attacks.

Purification and partial characterization of a new 85 KDa amyloidosis-related protein in chronic hemodialysis.

An 85 KDa protein was purified by a multistep procedure (ultracentrifugation, HPLC, SDS-PAGE) from sera and amyloid deposits of patients on chronic hemodialysis and was characterized as a novel protein on the basis of its NH2 terminus (KVQLVE-V). This protein was formed by two subunits with Mr of 55 and 30 KDa and had affinity for Thyoflavin T, a fluorescent dye which was employed for labelling the protein prior HPLC. The 85 KDa was the only fluorescent component of ultracentrifugates from the serum of hemodialyzed patients while in amyloid fibrils it coexisted in roughly equimolar amounts with beta 2-microglobulin. This new high molecular weight protein which accumulates in uremia, could be co-responsible with beta 2-microglobulin for hemodialysis-related osteoarticular amyloidosis.

Purification to homogeneity of alpha (III) collagen chain from human placenta by preparative electrophoresis.

A multiple electrophoretic method suitable for purification of type III collagen from a mixture of various collagen types is described. The technique is based on preparative electrophoresis in acid media and successive electroelution of the collagen fractions. By sodium dodecyl sulfate-polyacrylamide electrophoresis and immunoblotting, the collagen composition of the electroeluted fractions was characterized as a mixture of alpha (III), beta (III) and gamma (III) without any other visible contaminants. This technique enabled us to obtain large quantities of type III collagen from partial pepsin digests of human placenta suitable for further processing.

Effect of dietary protein restriction on renal purines and purine-metabolizing enzymes in adriamycin nephrosis in rats: a mechanism for protection against acute proteinuria involving xanthine oxidase inhibition.

1. A low protein diet prevents the development of proteinuria and glomerular damage in adriamycin experimental nephrosis without affecting renal haemodynamics. In this study the hypothesis was tested as to whether protein restriction is able to modulate the purine metabolic cycle and related enzymes such as xanthine oxidase, one of the putative effectors of adriamycin nephrotoxicity. 2. Renal activities of xanthine oxidase and purine nucleoside phosphorylase were markedly depressed in adriamycin-treated rats fed a 9% casein (low protein) diet compared with the group fed a 22% casein (normal protein) diet both 1 day after adriamycin administration and at the time of appearance of heavy proteinuria (day 15), whereas the activity of renal adenosine deaminase was unchanged. 3. The concentrations of the metabolic substrates of xanthine oxidase, i.e. hypoxanthine and xanthine, were constantly lower in renal homogenates of rats fed a low protein diet compared with those on a normal protein diet. In urine, uric acid, the product of hypoxanthine-xanthine transformation, was lower 1 day after adriamycin injection in protein-restricted rats compared with the group on a normal protein diet which showed a marked increase in its excretion. At the same time, the urinary efflux of adenosine 5'-monophosphate, which is the precursor nucleotide of the above-mentioned nucleosides and bases, was very high in rats fed a low protein diet, whereas it was absent in the group on a normal protein diet. 4. The progressive increment in proteinuria of glomerular origin (i.e. increased excretion of albumin and transferrin) typical of adriamycin-treated rats fed a normal protein diet was inhibited in the protein-restricted animals, which were normoproteinuric on day 10 and were only slightly proteinuric on day 15. 5. Like protein restriction, the pharmacological suppression of renal xanthine oxidase by dietary tungstate and the scavenging by dimethylthiourea of the putative free radical deriving from the action of xanthine oxidase, were associated with a similar (quantitative and qualitative) inhibition of glomerular proteinuria. 6. These data demonstrate that dietary protein restriction is associated with a block in purine metabolism within the kidney due to a marked reduction in the activities of two main enzymes of the cycle, i.e. purine nucleoside phosphorylase and xanthine oxidase, the latter being a putative effector of adriamycin nephrotoxicity. The partial reduction of proteinuria induced by a low protein diet is quantitatively and qualitatively comparable with the reduction induced by the specific block of renal xanthine oxidase or by the scavenging of OH.deriving from hypoxanthine and xanthine transformation.(ABSTRACT TRUNCATED AT 400 WORDS)

Analysis by isoelectric focusing of xanthine oxidase and NADH dependent enzymes in rat kidney.

Ultrathin isoelectric focusing was employed for analyzing xanthine oxidase and enzymes with NADH-dependent dehydrogenase activity in homogenates of rat kidney. After isoelectric focusing the enzymes were stained with specific assays where NBT is reduced upon incubation of the gel with xanthine (oxidase stain) and NADH (dehydrogenase stain) as substrates. A good separation of renal enzymes with dehydrogenase activities was obtained by using gels containing 2 M urea and by applying the sample at the anode. In these conditions 4 main isoforms with pI 6.4, 6.35, 6.5 and 6.6 were observed with the dehydrogenase stain but we were unable to demonstrate renal xanthine oxidase (XO) which seemed to be due to precipitation at the application point.

Hypertension and renal selectivity properties in diabetic microalbuminuria.

The renal selectivity properties towards albumin were evaluated in ten diabetic patients with arterial hypertension before and after the pharmacological normalisation of blood pressure, and were compared to 12 subjects with essential hypertension. While all patients of the control group were normoalbuminuric during hypertension, six of the diabetic group were microalbuminuric when hypertensive and became almost normoalbuminuric after blood pressure pharmacological control. All microalbuminuric diabetic patients presented altered properties of renal selectivity as epitomised by a non-preferential urinary excretion of glycosyl albumin (GA) (urinary GA/serum GA less than or equal to 1). At variance the selectivity properties were normal in normoalbuminuric diabetic patients and in essential hypertension. It was concluded that in diabetes mellitus arterial hypertension is associated with microalbuminuria when the renal properties of selectivity are altered, but does not implicate any proteinuric effect in those cases where the GBM function is preserved.

Preparative high performance chromatography of a major browning compound derived from lysine and glucose.

A major browning compound derived from lysine and glucose was purified by high performance chromatography on a RP8 column after several extractions in methanol plus acetonitrile. This compound was separated by a main contaminant corresponding to unreacted lysine by extracting the aminoacid after its derivatization with ninhydrin.