Chemical characterization of melanins in sheep wool and human hair

The color of hair and wool in mammals and feathers in birds is mostly determined by the quantity and quality of melanins that are synthesized in follicular melanocytes and transferred to keratinocytes. These are two chemically distinct types of melanin pigments: the black to brown eumelanins and the yellow to reddish pheomelanins. Melanins in sheep wool and human hair of various colors were characterized by HPLC methods to estimate 5,6-dihydroxyindole-2-carboxylic acid (DHICA)-derived units in eumelanins and benzothiazine units in pheomelanins. Melanins were also characterized by spectrophotometric methods after differential solubilization in alkalies. It was demonstrated that 1) black wool in Asiatic sheep contains eumelanin with the DHICA content similar to black mouse melanin, while black to brown melanins from human hair contain much lower ratios of DHICA-derived units, comparable to the slaty mutation in mice, 2) dark brown to brown hair in human contains eumelanin whose chemical properties are indistinguishable from those of black hair; 3) dark red wool and red human hair contain pheomelanic pigments whose chemical properties are rather different from those of yellow pheomelanins in mice, and 4) light brown, blonde, and red hairs in human can be differentiated from each other with this methodology.

Oxidized ethyl linoleate induces mucosal hypertrophy of the large intestine and affects cecal fermentation of dietary fiber in rats

Oxidized ethyl linoleate (OEL) was prepared by aeration at low temperature. Peroxide value (POV, mEq/kg lipid) of OEL was 1400; the major oxidized compounds were 9-hydroperoxy-cis, trans- and 13-hydroperoxy-trans, cis-octadecadienoate. Rats fed fiber-free or sugar-beet fiber (SBF, 100g/kg diet) diets were divided into three groups for each diet, and administered OEL (high OEL group), OEL diluted with ethyl linoleate (low OEL group, POV 700) and nonoxidized ethyl linoleate (EL group) through gastric tubes each day at 1400-1600 h (2.5 g/kg body wt) for 16 d. The relative wet weight, and DNA and protein contents of the cecal mucosa were higher in the high OEL groups than in the low OEL and EL groups in rats fed the fiber-free diet and in rats fed the SBF diet except for mucosal protein content. Spermidine concentration in cecal mucosa of rats fed the fiber-free diet was greater in the high OEL group than in the EL group. These results suggest that metabolism related to mucosal proliferation of the cecum was affected by the high dose of OEL. The total short-chain fatty acid (SCFA) concentration in the cecal contents of SBF-fed rats was 100% higher than the concentration in rats fed the fiber-free diet in the EL group, but the administration of low dose and high dose OEL lowered the SCFA concentration in fiber-fed rats to that of rats fed the fiber-free diet. Butyric acid concentration was markedly lowered by ingestion of OEL in a dose-dependent manner in rats fed the SBF diet. In contrast, the isobutyric acid concentration was higher in the OEL-treated groups than in the EL groups. We conclude that a low dose of OEL depresses cecal fermentation of dietary fiber with changes in SCFA composition, and that a high dose of OEL induces mucosal hypertrophy in the cecum. These data show that dietary oxidized lipids affect cecal metabolism and may be associated with colon cancer.

PLD activation in Chinese hamster ovary (CHO) cells transfected with PGF2 alpha receptor cDNA

Pertussis toxin-insensitive GTP-binding protein was observed to be involved in prostaglandin F2 alpha (PGF2 alpha)-induced phosphoinositide metabolism in Chinese hamster ovary (CHO) cells transfected with PGF2 alpha receptor cDNA (CHO-PGF2 alpha R cells) (Ito, S. et al. Biochem. Biophys. Res. Commun. 200: 756,1994). In the present study, we investigated PGF2 alpha-induced PLD activation in CHO-PGF2 alpha R cells. PLD activation was examined by measuring the production of [3H]phosphatidylbutanol ([3H]PBut), a specific product of the PLD-catalyzed transphosphatidylation reaction. PGF2 alpha-induced [3H]PBut formation was concentration-dependent with the maximal level obtained at 1 microM PGF2 alpha. The maximal [3H]PBut formation was observed at 2 min after addition of PGF2 alpha. Depletion of extracellular Ca2+ with EGTA suppressed PGF2 alpha-induced PLD activation by 50%. PKC inhibitors Ro31-8425 and calphostin C inhibited PGF2 alpha-induced [3H]PBut formation by 50%. PTK inhibitors genistein and herbimycin A failed to inhibit PGF2 alpha-induced PLD activation. A combination of maximal effective concentrations of PGF2 alpha (1 microM) and PMA (100 nM) enhanced PLD activation in an additive manner. Pretreatment of the cells with PMA for 2 h down-regulated PKC alpha and decreased PGF2 alpha-induced PLD activation. These results suggest that PLD activation by PGF2 alpha is mediated by both PKC-dependent and -independent pathways and that PKC alpha is involved in the former pathway.

Interleukin 1 beta markedly stimulates nitric oxide formation in the absence of other cytokines or lipopolysaccharide in primary cultured rat hepatocytes but not in Kupffer cells

To investigate whether a single inflammatory cytokine could stimulate nitric oxide formation in the absence of other cytokines or lipopolysaccharide (LPS), NO was measured by the redox chemiluminescence method in primary cultured rat hepatocytes and in rat Kupffer cells. Interleukin (IL) 1 beta, but neither IL-6, tumor necrosis factor alpha (TNF-alpha), interferon gamma (IFN-gamma), nor LPS stimulated NO formation in a dose-dependent manner and induced half-maximal effects at 30 pmol/L. Maximal stimulation was achieved at 12 to 16 hours after the addition of 1I nmol/L of IL-1 beta, and was 50- to 60-fold above basal levels in rat hepatocytes. The combined effect of these cytokines with LPS or IFN-gamma on NO formation was also examined. Neither LPS nor IFN-gamma affected the IL-1 beta-induced NO formation. TNF-alpha, however, stimulated IL-1 beta-induced NO formation, while IL-6 inhibited it, although independently these cytokines had no effect on NO formation. None of the cytokines tested stimulated NO formation in cultured rat Kupffer cells. In hepatocytes, the NO formation induced by IL-l beta was blocked by both the NO synthase (NOS) inhibitor NG-monomethyl-L-arginine (L-NMMA) and by IL-1 receptor antagonist (IL-1ra). Furthermore, IL-1 beta markedly increased NOS activity, and this increase in activity was accompanied by the expression of inducible NOS (iNOS) messenger RNA (mRNA). This study clearly demonstrated that IL-1 beta markedly stimulates NO formation in hepatocytes, in the absence of other cytokines or LPS.

Separation of functional domains for the alpha-1,4 and alpha-1,6 hydrolytic activities of a Bacillus amylopullulanase by limited proteolysis with papain

An amylopullulanase (APase) from alkalophilic Bacillus sp. KSM-1378 hydrolyzes both alpha-1,6 linkages in pullulan and alpha-1,4 linkages in other polysaccharides, each maximally active at an alkaline pH, to generate oligosaccharides. We analyzed proteolytic fragments that were produced by exposing pure APase to various proteases, to identify its catalytic domain(s). The intact, pure 210-kDa APase was partially digested with papain for a short time, yielding simultaneously two smaller non-overlapping active fragments, designated amylose-hydrolyzing fragment (AHF114, 114 kDa) and pullulan-hydrolyzing fragment (PHF102, 102 kda). The two truncated protein fragments, each containing a single catalytic domain, were purified to homogeneity. The purified AHF114 and PHF102 had similar enzymatic properties to the amylase and pullulanase activities, respectively, of intact APase. The partial amino-terminal sequences of APase and AHF114 were both Glu-Thr-Gly-Asp-Lys-Arg-Ile-Glu-Phe-Ser-Tyr-Glu-Arg-Pro and that of PHF102 was Thr-Val-Pro-Leu-Ala-Leu-Val-Ser-Gly-Glu-Val-Leu-Ser-Asp-Lsy-Leu. These results were direct evidence that the alpha-1,6 and alpha-1,4 hydrolytic activities were associated with two different active sites in this novel enzyme. Our alkaline APase is obviously a "biheaded enzyme".

Regulation of energy metabolism by interleukin-1beta, but not by interleukin-6, is mediated by nitric oxide in primary cultured rat hepatocytes

The effects of inflammatory cytokines (interleukin-1beta, interleukin-6, and tumor necrosis factor-alpha) on energy metabolism were studied in primary cultured rat hepatocytes. Adenine nucleotide (ATP, ADP, and AMP) content, lactate production, the ketone body ratio (acetoacetate/beta-hydroxybutyrate) reflecting the liver mitochondrial redox state (NAD+/NADH), and nitric oxide formation were measured. Insulin increased ATP content in hepatocytes and had a maximal effect after 8-12 h of culture. Both interleukin-1beta and interleukin-6, but not tumor necrosis factor-alpha, significantly inhibited the ATP increase time- and dose-dependently. Interleukin-1beta and interleukin-6 also stimulated lactate production. During the same period, interleukin-1beta but not interleukin-6 decreased the ketone body ratio. Furthermore, interleukin-1beta markedly stimulated nitric oxide formation in hepatocytes, and this increase was blocked by NG-monomethyl-L-arginine (a nitric oxide synthase inhibitor) and by interleukin-1 receptor antagonist. NG-monomethyl-L-arginine reversed inhibition of the ATP increase, decrease in the ketone body ratio, and increase in lactate production, which were induced by interleukin-1beta. Interleukin-1 receptor antagonist completely abolished all of the effects induced by interleukin-1beta. These results demonstrated that interleukin-1beta and interleukin-6 affect the insulin-induced energy metabolism in rat hepatocytes by different mechanisms. Specifically, interleukin-1beta inhibits ATP synthesis by causing the mitochondrial dysfunction, a process which may be mediated by nitric oxide.

Mechanisms of action of atrial natriuretic factor and C-type natriuretic peptide

After secretion by the heart, atrial natriuretic factor (ANF) circulates in plasma, whereas C-type natriuretic peptide (CNP), which is found in abundance in the endothelium, may regulate vascular tone in a paracrine manner. However, there is little information on the effect of CNP on renal microvessels. We hypothesized that CNP dilates the afferent arteriole via the nitric oxide pathway, whereas ANF acts directly on vascular smooth muscle cells. When we perfused rat kidneys with minimal essential medium and bovine serum albumin at 100 mm Hg and examined the juxtamedullary afferent arterioles, neither CNP nor ANF was found to have any effect. When the peptides were added to arterioles preconstricted with norepinephrine, CNP and ANF dilated them in a similar fashion; diameters increased by 25 +/- 4% (n=7) and 29 +/- 6% (n=6) at 10(-7) mol/L, respectively (P < .008). Pretreatment with 10(-4) mol/L N-nitro-L-arginine methyl ester (L-NAME) or 5 x 10(-6) mol/L indomethacin blocked CNP-induced dilation; dilation by ANF was unaffected by indomethacin (52 +/- 25%, n=5) and potentiated by L-NAME (73 +/- 14%, n=5). Thus, CNP dilates the afferent arterioles via the prostaglandin/nitric oxide pathway, whereas ANF dilates them directly. This difference may be important in controlling glomerular hemodynamics.

20-HETE requires increased vascular tone to constrict rabbit afferent arterioles

Renal production of 20-hydroxyeicosatetraenoic acid (20-HETE), a cytochrome P-450-dependent arachidonate metabolite, increases during development of hypertension in spontaneously hypertensive rats, and inhibition of its production prevents hypertension. Since 20-HETE is a potent vasoconstrictor, these findings suggest that 20-HETE may contribute to the development of hypertension by elevating renal vascular resistance. In this study we examined the direct action of 20-HETE on the afferent arteriole, a vascular segment crucial to the control of renal vascular resistance. Rabbit afferent arterioles were microperfused at 60 mm Hg in vitro, and 20-HETE was added to the lumen. Although 20-HETE (10(-10) to 10(-6) mol/L) had no effect on the diameter of non-treated afferent arterioles (n=6), it caused dose-dependent constriction when vascular tone was increased with norepinephrine (0.3 micromol/L); 20-HETE at 10(-6) mol/L decreased diameter by 43 +/- 4% (n=6, P < .001). This constriction was abolished by disrupting the endothelium (n=5). Moreover, pretreatment with the cyclooxygenase inhibitor indomethacin (50 micromol/L) or the thromboxane/endoperoxide receptor antagonist SQ29548 (1 micromol/L) significantly (P < .03) attenuated 20-HETE-induced constriction: 20-HETE at 10(-6) mol/L constricted norepinephrine-treated afferent arterioles by 28 +/- 3% (n=6) and 25 +/- 4% (n=5), respectively. These results demonstrate that an increase in afferent arteriolar tone is required for the vasoconstrictor action of 20-HETE, which is partly mediated by the endothelial cyclooxygenase pathway. THus, increased production of 20-HETE in the kidney and increase in afferent arteriolar tone, both of which often precede the development of hypertension, may synergistically contribute to the development of hypertension by elevating renal vascular resistance.

Apoptosis-related fas antigen on memory T cells in aqueous humor of uveitis patients

To investigate the role of lymphocytes in the pathogenesis of uveitis, we analyzed the expression of memory markers, CD29 and CD45RO antigens, and apoptosis-related Fas antigen on T lymphocytes in the aqueous humor (AH) and peripheral blood (PB) from patients with uveitis. Using three-color flow cytometry, we assessed the number of T lymphocyte subsets that stained with fluorescence-conjugated anti-CD3, CD4, CD8, CD29, CD45RA, CD45RO, HLA-DR, and Fas monoclonal antibodies in the AH and PB from 19 patients with active uveitis who were diagnosed as having sarcoidosis, Vogt-Koyanagi-Harada disease, HLA-B27+ uveitis, or idiopathic uveitis. Cells from AH and PB were evaluated by light and electron microscopy before and after 6 h of incubation. The majority of lymphocytes in AH but not in PB, were CD3+HLA-DR+ (activated) T cells. The percentage of CD4+ lymphocytes was significantly higher in uveitic AH than in PBL (P < 0.01). While the percentage of CD4+ CD45RA+ (naive) cells within T cells was much lower in uveitic AH than in PB, the percentage of CD4+CD29+ or CD4+CD45RO+ (memory) cells was significantly higher in uveitic AH than in PBL (P < 0.01). Fas antigen was expressed preferentially on memory cells in uveitic AH. Apoptosis of cells in the AH was observed by microscopically following after incubation with no stimulation. Lymphocytes from the AH of patients with uveitis were more activated than those from PB. The majority of T lymphocytes from uveitic AH expressed memory markers and Fas antigen. Results suggest that an increase in the number of Fas+ memory T lymphocytes in AH is involved in the pathogenesis of uveitis.

[Serum levels of solubule tumor necrosis factor (TNF) receptors in patients with pulmonary tuberculosis]

Tumor necrosis factor alpha (TNF-alpha) is released from cells of monocyte/macrophage lincage and mediates the development of a variety of clinical and pathomorphological features in various infectious diseases, autoimmune diseases and cancer. In the case of tuberculosis, it is suggested that the release of TNF-alpha in the affected regions and into the circulation could account for the pathological and clinical features such as the development of necrotic lesions and fever and weight loss in TB patients. In the present study, the levels of soluble TNF receptor type I (sTNFR type I) and type II (sTNFR type II) and TNF-alpha in the sera of patients with pulmonary TB were assayed, and we tried to know whether these levels have clinical significance in determining the disease activity in TB patients. The serum levels of both sTNFR types I and II were significantly higher in TB patients (n = 22) who were previously untreated than in the healthy control (n = 14): for sTNFR type I, 2.82 +/- 1.37 ng/ml vs. 1.40 +/- 0.33 ng/ml (p < 0.0001), and for sTNFR type II, 3.83 +/- 1.76 ng/ml vs. 1.62 +/- ng/ml (p < 0.0001). The serum levels of sTNFR types I and II in TB patients showed significant correlations with their serum levels of CRP. The serum levels of TNF-alpha in these TB patients was 2.21 +/- 1.72 pg/ml, whereas TNF-alpha was not detectable in the sera of 9 healthy control. The serum levels of sTNFR type I and II were significantly higher in cavitary TB (n = 17) than in non-cavitary TB (n = 5). When TB patients were treated with antituberculosis drugs and clinical improvements were achieved, the elevated levels of sTNFR type I and TNF-alpha in the sera of same 5 patients measured before starting treatment showed significant decline and the serum levels of sTNFR type II showed also declined, however, the decline was statistically not significant. From all the results obtained in this study, we conclude that the assay of the serum levels of sTNFR in TB patients is useful in the evaluation of the disease activity of TB.

Purification of alkaline proteases from a Bacillus strain and their possible interrelationship

Alkalophilic Bacillus sp. KSM-K16 produced three alkaline proteases, as detected by polyacrylamide gel electrophoresis (PAGE). The major protease, designated M protease, was recently purified to homogeneity and its properties were characterized. In the present study, two minor proteases, designated H protease and N protease, were purified to homogeneity from cultures of this organism. H protease had a molecular mass of 28 kDa, as estimated by sodium dodecyl sulfate/PAGE (SDS-PAGE) and its maximum activity against casein was observed at pH 11.0 and at 55 degrees C. N protease consisted of two polypeptide chains with molecular masses of 12.5 kDa and 14.5 kDa, as estimated by SDS-PAGE, although it migrated as a single protein band during non-denaturing PAGE. Its maximum activity was observed at pH 11.0 and at 60 degrees C. The amino-terminal sequences of H protease and of the 14.5-kDa polypeptide of N protease were identical to that of M protease. The electrophoretic relationship between the three enzymes was examined after they had been stored at different pH values and at 5 degrees C. M protease was converted to H protease more rapidly at pH 11 than at pH 8 or below, and H protease was converted to M protease at pH 8 or below but not at pH 11. N protease appeared to be the autolytic product of the M and H proteases.

Influence of NaCl concentration at the macula densa on angiotensin II-induced constriction of the afferent arteriole

The macula densa, a plaque of specialized tubular epithelial cells, monitors NaCl concentrations in tubular fluid and controls resistance of the glomerular afferent arteriole (AA). In vivo micropuncture studies suggest that there are significant interactions between angiotensin II (Ang II) and macula densa control of glomerular hemodynamics. We tested the hypothesis that Ang II causes stronger constriction of the AA when NaCl concentration at the macula densa is elevated. Rabbit AAs and the attached macula densa were simultaneously microperfused in vitro, and dose-response curves to Ang II were obtained when the macula densa was not perfused or was perfused with either low NaCl (Na+, 26 mEq/L; Cl-, 7 mEq/L) or high NaCl (Na+, 84 mEq/L; Cl-, 65 mEq/L). Ang II induced stronger constriction when the macula densa was perfused with high NaCl; the decrease in diameter at 100 pmol/L was 29 +/- 5.6% (n= 7) compared with 2.1 +/- 1.2% (n=8) for the nonperfused macula densa or 6.1 +/- 4.2% (n=7) for low NaCl (P < .002). However, there was no such difference in the action of norepinephrine. Adding furosemide (10 micromol/L) to the macula densa perfusate abolished the difference in Ang II action between low and high NaCl at the macula densa. Since AA tone is higher when the NaCl concentration at the macula densa is elevated, we tested whether augmented Ang II action is due to higher AA tone. Preconstriction of the AA by 20% with norepinephrine had no effect on Ang II action. Thus, our results demonstrate that sensitivity of the AA to Ang II increases when NaCl concentration at the macula densa is elevated. Such modulation of Ang II action by macula densa NaCl concentration may be important in the control of glomerular hemodynamics.

Tubuloglomerular feedback

The macula densa, a plaque of specialized tubular epithelial cells located in the distal tubule, monitors the NaCl concentration of the tubular fluid and sends an as of yet unidentified signal to control glomerular hemodynamics. In this mechanism, called tubuloglomerular feedback (TGF), an increase in NaCl concentration at the macula densa constricts the glomerular afferent arteriole and thus decreases the single-nephron GFR. Along with the myogenic response, TGF significantly contributes to renal autoregulation. In addition, the macula densa also controls the rate of renin release, and hence the level of angiotensin II. Studies indicate that an appropriate interaction between TGF and the renin-angiotensin system is essential for body fluid and electrolyte homeostasis in the face of rather big variations in daily salt intake. Thus, alterations in TGF may play an important role in the pathogenesis/pathophysiology of various diseases such as hypertension, diabetes mellitus and congestive heart failure.

Transesophageal pulsed Doppler echocardiographic study of pulmonary venous flow in mitral stenosis

For evaluation of pulmonary venous flow (PVF) in mitral stenosis, transthoracic and transesophageal echocardiography were performed in 33 patients with mitral stenosis and 20 normal controls. The peak systolic flow velocity of the PVF was significantly lower in patients with mitral stenosis and atrial fibrillation. The peak diastolic flow velocity of the PVF was significantly lower in the patients with mitral stenosis than in normal controls. The diastolic wave recorded as laminar flow in the mitral stenosis group showed a peak in the rapid filling phase with a gradually descending slope of velocity during mid to late diastole. There was a significant negative correlation between the peak diastolic flow velocity of the PVF and the pressure half time from transmitral flow obtained by continuous wave Doppler in the mitral stenosis group. These results demonstrate that evaluation of the PVF is helpful in understanding hemodynamic events between the left atrium and left ventricle in patients with mitral stenosis.

Influence of anti-hypertensive drugs on glomerular hemodynamics

Alterations in glomerular hemodynamics may play an important role in the progression of renal dysfunction. Accordingly, treating not only systemic hypertension, but also glomerular hypertension is important for conservation of renal function in patients with renal disease. However, glomerular capillary pressure does not necessarily change in parallel with systemic blood pressure due to unique mechanisms that control the resistance of glomerular afferent and efferent arterioles. While myogenic response and tubuloglomerular feedback play an important role in controlling afferent arteriolar resistance, angiotensin II is a major determinant of efferent arteriolar tone. Calcium antagonists block almost all mechanisms that constrict the afferent arteriole, rendering glomerular capillary pressure dependent on systemic pressure. On the other hand, angiotensin-converting enzyme inhibitors dilate efferent arterioles, thereby lowering glomerular capillary pressure. Such differences should be taken into account when selecting adequate drugs for the treatment of hypertension with various degrees of renal dysfunction.

High prevalence of arthropathy in HTLV-I carriers on a Japanese island

OBJECTIVE

To determine the aetiological relationship between human T cell leukaemia virus type-I (HTLV-I) and arthritis, by performing an epidemiological study of the inhabitants of Tsushima, an island northwest of the main island of Kyushu, Japan, which is an endemic area of HTLV-I.

METHODS

A total of 7087 people underwent an annual health check, and those with arthropathy had further physical and radiological examinations by rheumatologists. The presence of HTLV-I antibody was determined by the particle agglutinin method, and integration of the proviral DNA in peripheral lymphocytes was confirmed by polymerase chain reaction.

RESULTS

HTLV-I was positive in 26.1% of inhabitants; the incidence increased to 37.0% in patients with symptoms of polyarthritis. The prevalence of rheumatoid arthritis (RA) was significantly different between HTLV-I carriers (0.56%) and non-carriers (0.31%). The stage of bone destruction in HTLV-I carriers with articular symptoms was milder than that in RA patients without HTLV-I. The relative risk of HTLV-I infection for polyarthritis was 1.66 (p < 0.05).

CONCLUSION

This is the first epidemiological report clarifying the association between HTLV-I and polyarthritis. Our results suggest that this viral infection has a relationship to RA.

Aberrant growth of granulocyte-macrophage progenitors in juvenile chronic myelogenous leukemia in serum-free culture

We investigated the properties of granulocyte-macrophage (GM) progenitors obtained from patients with juvenile chronic myelogenous leukemia (JCML). CD34+ bone marrow cells from a patient with JCML, unlike normal bone marrow cells, generated a large number of cells in serum-containing liquid culture without additional hematopoietic factors. In serum-deprived culture, only granulocyte colony-stimulating factor (G-CSF) had a modest stimulatory effect on GM colony growth in normal controls. In contrast, stem cell factor (SCF), granulocyte-macrophage colony-stimulating factor (GM-CSF), and interleukin-3 (IL-3), as well as G-CSF, when tested individually, generated significant numbers of GM colonies in some JCML patients. All two-factor combinations generated significantly more GM colonies in JCML compared with normal controls. In particular, GM-CSF plus SCF exerted an interaction equivalent to the all-factor combination in most patients. Significant differences in the size and constituent cells of GM colonies stimulated by GM-CSF plus SCF were also observed. These results suggest that one possible mechanism for the excessive cell production in JCML is the strong proliferation of GM progenitors induced by hematopoietic factors, especially SCF. According to immunofluorescent analysis, however, it is unlikely that this multiplication is due to an increase in the cell surface expression of c-kit receptors on JCML progenitors.

Changes in transmitral and pulmonary venous flow velocity patterns after cardioversion of atrial fibrillation

To examine the recovery time of left atrial mechanical function after electrical cardioversion of atrial fibrillation, we recorded transmitral flow, pulmonary venous flow velocities, and interatrial septal motion during atrial systole within 24 hours (16 +/- 5 hours) and 10 days after cardioversion in 25 patients with atrial fibrillation, including 6 patients with hypertension, 4 with ischemic heart disease, 2 with alcoholic heart disease, 5 with dilated cardiomyopathy, and 8 with no evidence of underlying heart disease. With the exception of the five patients with dilated cardiomyopathy, the peak atrial systolic transmitral and pulmonary venous flow velocities, peak first systolic velocity of pulmonary venous flow, duration of both atrial systolic waves, and amplitude of the interatrial septal motion during atrial systole decreased markedly within 24 hours after cardioversion and increased 10 days after cardioversion. These results suggest that active atrial systolic and relaxant variables obtained from transmitral and pulmonary venous flow velocities may reflect left atrial mechanical function after cardioversion of atrial fibrillation.

Clinical significance of the apical late systolic ejection murmur: a new phonocardiographic sign indicating dynamic mid-left ventricular obstruction

Systolic ejection murmurs of the left heart usually have their peak during early to mid-systole. Few reports have addressed ejection murmurs with their peak at late systole. We evaluated the clinical significance of an apical systolic ejection murmur with a peak intensity during late systole using Doppler and two-dimensional (2-D) echocardiography and phonocardiography. The apical late systolic ejection murmur was observed in 9 of 13 consecutive patients with mid-left ventricular obstruction. We investigated the ejection flow velocity and the timing of maximum velocity at the three different sites of the left ventricle, the left ventricular cavity shape, and the timing of the peak murmur intensity in these nine patients (late-murmur group). The same parameters were also examined in 8 consecutive patients with mid-systolic ejection murmurs (mid-murmur group), 10 with early systolic ejection murmurs (early-murmur group), and 7 controls without murmurs. Patients with aortic stenosis were excluded. The mid-ventricular ejection flow velocity was significantly higher in the late-murmur group than in the other three groups; that of the outflow tract was markedly higher in the mid-murmur group. The ejection flow velocity at the aortic orifice of patients in the early-murmur group was significantly high compared with that of the controls. The timing of the peak murmur intensity in each group correlated with that of the peak flow signal at the corresponding site with maximum velocity. In all patients in the late-murmur group, 2-D echocardiography revealed a systolic narrowing of the cavity at the mid-ventricle. Amyl nitrite inhalation induced a marked increase in the intensity of the murmur without evidence of appearing or increasing mitral regurgitation. It was concluded that the apical ejection murmur with a late systolic peak intensity is a new phonocardiographic sign indicative of dynamic, mid-left ventricular obstruction. This murmur should be differentiated from the mitral regurgitant murmur.

In vitro properties and in vivo behavior of technetium-99m labeled fibrinogens

Fibrinogen was labeled with Tc-99m by two methods and in vitro stability and the in vivo behavior in mice were studied. The Tc-99m labeling was performed by mixing an unreduced fibrinogen (UnFib) or a reduced fibrinogen (ReFib) with Tc-99m pertechnetate in the presence of stannous chloride. In both of them, chelation with Tc-99m resulted in a single radiochemical product. For the in vitro stability studies, Tc-99m labeled fibrinogen (Tc-99m UnFib) was prepared with UnFib, and transchelation with cysteine solution was easy to produce compared to Tc-99m labeled fibrinogen (Tc-99m ReFib) prepared with ReFib. The radioactivity bound to clottable protein for Tc-99m UnFib and Tc-99m ReFib was about 70% and about 69%, respectively. The in vivo behavior of these labeled fibrinogens was studied, and their efficiencies for imaging an abscess and Ehrlich tumor in mice were determined with a gamma camera. Technetium-99m UnFib underwent a rapid partial exchange of the Tc-99m with compounds of the blood buffer system in vivo, resulting in early biologically active and would be incorporated into the abscess and tumor. The uptake in the abscess increased slightly over time with Tc-99m ReFib, but the abscess to blood and abscess to muscle ratios were 0.09 and 2.6 at 5 hr, respectively. Clearly delineated images of abscess were obtained beginning at about 5 hr after injection. The tumor to blood and tumor to muscle ratios were 0.05 and 1.4 at 5 hr, respectively. The Ehrlich tumor image in mice was slightly visible at 10 hr. The short half-life of Tc-99m was inappropriate for fibrinogen with a low pharmacokinetic value, because it was necessary for imaging of the abscess and tumor to take a long time.

Angiotensin II action in isolated microperfused rabbit afferent arterioles is modulated by flow

We have recently presented evidence that endogenous nitric oxide (NO) and prostaglandins (PGs) modulate angiotensin II (Ang II) action in microperfused afferent arterioles (Af-Arts). Because flow may be a physiological stimulus of endothelial release of NO and PGs, we tested the hypothesis that flow through the lumen of the Af-Art stimulates the endothelium to produce NO and PGs, which in turn modulate the action of Ang II. We microdissected the terminal segment of an interlobular artery together with two Af-Arts, their glomeruli and efferent arterioles (Ef-Art). The two Af-Arts were perfused simultaneously from the interlobular artery, while one Ef-Art was occluded. Since the arteriolar perfusate contained 5% albumin, oncotic pressure built up in the glomerulus with the occluded Ef-Art and opposed the force of filtration, resulting in little or no flow through the corresponding Af-Art. Thus this preparation allowed us to observe Ang II action in free-flow and non-flow Af-Arts simultaneously. Ang II-induced constriction was weaker in free-flow than non-flow Af-Arts, with the luminal diameter decreasing by 8 +/- 2% and 23 +/- 3% at 10(-9) M, respectively (P < 0.013 free-flow vs. non-flow; N = 9). Disrupting the endothelium augmented Ang II action in free-flow (33 +/- 5.1%; P < 0.01 vs. intact endothelium) but not non-flow Af-Arts (31 +/- 5.3%), thus abolishing the differences between them (N = 8). Pretreatment with an inhibitor of either NO synthase (N-nitro-L-arginine methyl ester) or cyclooxygenase (indomethacin) augmented Ang II action more in free-flow than non-flow Af-Arts, likewise abolishing the differences between them. These results suggest that intraluminal flow modulates the vasoconstrictor action of Ang II in Af-Arts via endothelium-derived NO and PGs. Thus flow may be important in the fine control of glomerular hemodynamics.