'Dynamic' Starling mechanism: effects of ageing and physical fitness on ventricular-arterial coupling

Cardiovascular diseases increase with advancing age, associated with left ventricular and arterial stiffening in humans. In contrast, daily exercise training prevents and/or improves both ventricular and arterial stiffening with ageing. We propose a new approach to quantify the dynamics of the Starling mechanism, namely the beat-to-beat modulation of stroke volume (SV) caused by beat-to-beat alterations in left ventricular filling, which we propose reflects the complex interaction between ventricular and arterial stiffness. We hypothesized that the dynamic Starling mechanism would be impaired with ageing, and that this impairment would be prevented and restored by daily exercise training. Two different approaches were employed: (1) a cross-sectional study to assess the effects of ageing and life-long exercise training; and (2) a longitudinal study to assess the effects of one-year endurance training in the elderly. Spectral transfer function gain between beat-to-beat changes in left ventricular end-diastolic pressure and SV was used as an index of the dynamic Starling mechanism. Gain was significantly lower in the sedentary elderly (70 ± 3 years) than in both young individuals (27 ± 6 years) and Masters athletes (68 ± 3 years), and it was significantly lower in Masters athletes than in young controls (elderly: 0.37 ± 0.11; Masters athletes: 0.96 ± 0.55; young: 1.52 ± 0.42 ml m⁻² mmHg⁻¹, mean ± s.d. ). Gain increased by 65% after one-year exercise training in the elderly, although the response was quite variable ( P = 0.108). These findings suggest that the dynamic Starling mechanism is impaired with human ageing possibly due to ventricular–arterial stiffening. Life-long daily exercise training may minimize this impairment, although the effect may be limited particularly when started later in life.     

Peculiarity of small lymphocytes in the thymic medulla in neonatal mice

Summary Karyometric studies were made of lymphocytes for the cortex and medulla of the thymus of mice at various ages from birth to adulthood. From the results obtained it was evident that in early neonate mice, medullary small lymphocytes were characterized by having larger nuclei than cortical small lymphocytes. On the basis of cytological features, such medullary lymphocytes could reasonably be classified as small lymphocytes rather than medium lymphocytes, although they had larger nuclei than typical small lymphocytes. Such peculiar small lymphocytes with larger nuclei were preponderant in the medulla during early neonatal life, but they rapidly decreased in number with advancing age, although they were present in a small proportion even in adults. The findings on the occurrence of such peculiar small lymphocytes in the medulla were discussed in relation to the maturation pathway of lymphocytes in the thymus.Supported by research grant from the Education Ministry (No. 748046, 1972).     

The inferior supernumerary renal arteries: A classification into three types

Among cases that had multiple renal arteries on one side, an inferior supernumerary renal artery was found in 24/270 cases (ca. 9%) on the right and in 19/270 cases (ca. 7%) on the left, together with the usual renal artery. We have noticed that there are correlations between their levels of origin from the aorta and their positional relation to the ureter and the inferior vena cava (IVC). An inferior supernumerary renal artery (InfRA) of lower origin passes in front of the IVC and behind the ureter. An InfRA of middle origin passes in front of both the IVC and the ureter. An InfRA of upper origin passes behind the IVC and in front of the ureter or renal pelvis. In addition there was a tendency for the lower origin type to have an ureteric branch, while the middle and upper origin types had a gonadal branch. These findings suggest that different derivations lead to the inferior supernumerary renal arteries.     

Molecular design of biodegradable functional polymers, 3. Biodegradability and functionality of poly[(sodium acrylate)-co-(vinyl alcohol)]

As a design for a biodegradable functional polymer, compositionally homogeneous poly[(sodium acrylate)-co-(vinyl alcohol)] [P(SA-co-VA)], containing varying amounts of vinyl alcohol groups as biodegradable segments were prepared and their biodegradability and builder performance in detergent formulations were analyzed with respect to the successive vinyl alcohol length. It was found that the acrylate copolymers having more than 80 mol-% vinyl alcohol content showed biodegradability. That is, P(SA-co-VA) having a vinyl alcohol chain length of more than about 5–6 is cleaved by PVA-degrading microbes. This indicates that the vinyl alcohol blocks, which act as biodegradable segments, should be incorporated into the polymer chain in such a manner that they are accepted as substrates by the PVA-degrading enzymes.     

Comprehensive analysis of monoclonal antibodies against detergent-insoluble membrane/lipid rafts of HL60 cells

Glycosphingolipids and cholesterol are principal components of plasmamembrane microdomains, i.e. lipid rafts. Recent studies revealed the possible presence of a variety of microdomains that distinctly differ in terms of their molecular composition and functions. To understand their precise structures and functions, we produced monoclonal antibodies (MAbs) by immunizing mice to the microdomains prepared from a fraction of detergent-insoluble membrane (DIM) of HL60 cells. Biochemical characterization of the antigen epitopes led to classification of the MAbs into two groups. One group consists of MAbs that react with lipids such as phosphatidylglucoside, lysophosphatidylinositol, and gangliosides (GM1a and GD1b), and the other consists of MAbs that react with proteins such as annexin I, aminopeptidase N and acrogranin. Immunofluorescence staining of HL60 cells with the MAbs, except for the MAbs that recognize lysophosphatidylinositol or annexin I, resulted in patchy-like images of the cell membranes. Interestingly, MAbs belonging to the former group had the potential to induce cell proliferation/differentiation in vitro. Our MAbs against the DIM fraction of HL60 cells can be valuable tools for the study of membrane microdomains.     

Investigation of albumin synthesis in rat livers during the perinatal period using immunocytochemistry andin situ hybridization

The immunoreactivity of albumin (ALB) was observed in the hepatocytes of fetal rats on day 18 of gestation, and was especially observable in immature rough endoplasmic reticulum (rER) and Golgi apparatus (GA); by then, a small amount of silver grains of ALB mRNA could already be detected. Just after birth, immunoreactivity of ALB could be observed in fine granules or diffusely in all hepatocytes, and was present in rER and GA. One week after birth immunoreactivity of ALB was observed in all hepatocytes and was visible in developed rER and GA; the grains of ALB mRNA were present in all hepatocytes.     

A Clinical Cassette Dosing Study for Evaluating the Contribution of Hepatic OATPs and CYP3A to Drug-Drug Interactions

Purpose

To demonstrate the relative importance of organic anion-transporting polypeptides (OATPs) and cytochrome P450 3A (CYP3A) in the hepatic elimination of substrate drugs.

Methods

A cocktail of subtherapeutic doses of bosentan, repaglinide, clarithromycin, darunavir, simeprevir, and midazolam (CYP3A probe) was administered orally to eight healthy volunteers. Rifampicin (OATP inhibitor; 600 mg, p.o.) and itraconazole (CYP3A inhibitor; 200 mg, i.v.) were coadministered with the cocktail in the second and third phases, respectively. Based on the extended clearance concept, in vivo β values (fraction of metabolism plus biliary excretion among all the intracellular fates of drugs including basolateral efflux) and R_dif values (ratio of diffusional uptake to active uptake) were estimated.

Results

Rifampicin increased plasma AUCs of bosentan (×3.2), repaglinide (×1.9), clarithromycin (×1.9) and simeprevir (×7.2). Itraconazole increased those of clarithromycin (×2.3), simeprevir (×2.2) and midazolam (×3.7), which had relatively small β values. The plasma AUC of bosentan (with relatively large β and small R_dif) was dominated by OATP-mediated uptake. The AUC of simeprevir was also dominated by OATP-mediated uptake because of its small R_dif value.

Conclusions

The DDI study clarified the rate-determining processes of OATP/CYP3A substrates. Our analyses provide valuable information for predicting complex drug–drug interactions involving multiple processes.

     

Changes in blood viscosity with mucopolysaccharide polysulfate

We examined the dose-dependent effects of mucopolysaccharide polysulfate (MPS) on coagulation variables and whole-blood viscosity in human blood. Both 0.01% and 0.1% MPS significantly reduced levels of both fibrin monomer and thrombin-antithrombin III complex in a manner similar to that of 2.0 IU/ml heparin sodium. Furthermore, MPS dose-dependently decreased whole-blood viscosity, as measured with an oscillation viscometer. Because MPS can be applied in creams and gels, percutaneous application of MPS may effectively reduce whole-blood viscosity in local veins.     

The effect of ultrapure dialysate on improving renal anemia

BACKGROUND: Renal anemia is a very serious problem in hemodialysis patients. In this regard, the investigation was focused on whether ultrapure dialysate could improve renal anemia and the mechanism of renal anemia. METHODS: Ultrapure dialysate was used over a 2 years period for 61 patients on maintenance hemodialysis. During this period, the changes in renal anemia and red blood cell life span were investigated. The changes in the latter were evaluated using the creatine concentration in red blood cell. RESULTS: The hemoglobin concentration, RBC count, and hematocrit concentration before the use of the ultrapure dialysate were 9.1 +/- 0.2 g/dL, 309.9 +/- L7.2 x 10(4)/microL, and 28.8 +/- 0.6%, respectively. These values significantly increased to 10.2 +/- 0.1 g/dL, 349.7 +/- 5.6 x 10(4)/microL, and 32.6 +/- 0.3%, respectively, after 2 years of ultrapure dialysate use. The increase in reticulocyte count indicated enhanced erythropoiesis by ultrapure dialysate. The red blood cell life span evaluated by creatine concentration in red blood cell was also prolonged after the use of ultrapure dialysate. CONCLUSIONS: Ultrapure dialysate is considered to improve the renal anemia of dialysis patients by promoting erythropoiesis and prolonging red blood cell life span.     

Significance of Serum Neuron-specific Enolase as a Predictor of Relapse of Small Cell Lung Cancer

We conducted a prospective study to evaluate the significanceof serum neuron-specific enolase (NSE) as a predictor of relapseof small cell lung cancer (SCLC). Patients entered into thestudy were drawn from those who had shown a complete or partialresponse to first-line chemotherapy with a concurrent declinein the NSE level to less than 10 ng/ml. When the serum NSE levelincreased to more than 15 ng/ml, the patient was restaged onthe basis of clinical, radiological, and bronchoscopic examinations.During the period from August 1988 to December 1990, 57 patientswith SCLC were enrolled and followed up until May 1992; Of thesepatients, 45 had clinical relapses, and 14 (31%) of them showeda clear elevation of the serum NSE level prior to the clinicalrecognition of relapse. Although one false-positive case wasnoted, this involved only a transient elevation of the NSE level.In patients who showed increased NSE levels, the relapses occurredin more difficult to detect silent sites such as the adrenalgland, liver, and deep lymph nodes. In addition, the percentageof patients demonstrating high NSE levels who were able to benefitfrom salvage chemotherapy was higher than for those who didnot (P<0.05). Our results indicate that serial NSE measurementsare useful for the early prediction of SCLC relapse and shouldhelp to facilitate early administration of salvage chemotherapyfor affected patients.(P<0.05)