Acromegaly associated with Chiari-I malformation and polycystic ovary syndrome

We report a 19-year-old female case of acromegaly associated with Chiari-I malformation and polycystic ovary syndrome. She also had syringomyelia and thoracic scoliosis. Although the association of acromegaly and Chiari-I malformation was by chance, exaggerated secretion of growth hormone may have aggravated the scoliosis. The incidence of polycystic ovary in acromegalic patients remains to be elucidated. However, elevation of plasma insulin and insulin-like growth factor, that is usually observed in patients with acromegaly, could stimulate androgen production in the ovaries. The patient was successfully treated with transsphenoidal adenomectomy for pituitary tumor and correction surgery for thoracic scoliosis.

Antibodies to beta 2-glycoprotein I and clinical manifestations in patients with systemic lupus erythematosus

OBJECTIVE

To investigate whether anticardiolipin antibodies (aCL) in patients with systemic lupus erythematosus (SLE) bind to beta 2-glycoprotein I (beta 2GPI), and to search for a relationship between the presence of IgG and/or IgM anti-beta 2GPI antibody and clinical manifestations in SLE patients.

METHODS

IgG and IgM anti-beta 2GPI in 308 Japanese SLE patients were measured using phospholipid-independent enzyme immunoassays. Relationships to clinical histories and to various laboratory data were examined.

RESULTS

The values of anti-beta 2GPI and aCL, as measured by conventional enzyme immunoassay, showed a strong correlation, but the anti-beta 2GPI assay was more useful in distinguishing beta 2GPI-dependent aCL from beta 2GPI-independent aCL. The presence of IgG anti-beta 2GPI was associated with an increased frequency of a history of thrombosis. Comparisons of various laboratory data suggested that the titer of anti-beta 2GPI may fluctuate with disease activity.

CONCLUSION

The results suggest that pathogenic aCL is directed against structurally altered beta 2GPI and that enzyme immunoassay for anti-beta 2GPI may prove useful in evaluating the risk of thrombosis and monitoring the clinical course in patients with SLE.

Transcatheter arterial embolization as treatment for life-threatening maxillofacial injury

A rare case of massive maxillofacial hemorrhage, which was controlled by transcatheter arterial embolization, is reported. A 23-year-old man with massive nasal and oral hemorrhage caused by maxillofacial fracture was admitted. Emergency angiography demonstrated extravasation of contrast material from the posterior superior alveolar artery, which was immediately embolized using gelatin sponge particles. This case shows that transcatheter arterial embolization is useful and effective for the treatment of massive hemorrhage resulting from severe maxillofacial injury.

[Variations of serum amyloid A protein and interleukin-6 in patients with low concentration of serum C-reactive protein]

Both C-reactive protein (CRP) and Serum amyloid A protein(SAA) are determined as an indicator of inflammation and tissue damage. But serum CRP in the range less than 10 micrograms/dl was not correlated with SAA. We determined CRP, SAA and interleukin-6(IL-6) in sera of patients who had received corticosteroid therapy. CRP decreased extremely after administration of more than 50 mg/day corticosteroid. However, SAA and IL-6 levels changed independently from CRP levels. In the patients under long-term corticosteroid therapy, CRP decreased rapidly to the level below the reference range and remained low, while SAA decreased but to the level in the reference range, and IL-6 levels was unchanged. When they were complicated with infectious disease during the corticosteroid therapy, CRP increased to or above the reference level but not so markedly, however, SAA increased markedly and exceeded the upper reference range three or four days earlier than the day of CRP increase. It is suggested that serial SAA monitoring will be reliable for the early diagnosis of infection if the patients is taking corticosteroid therapy.

[Correlation of interleukin-2 (IL-2) responsiveness by egg white-stimulated lymphocytes with hen egg oral provocation test in atopic children]

One hundred and twenty five cases of atopic children such as atopic dermatitis and bronchial asthma were orally provocated with rare hen egg every 20 minutes one by one upto the whole amount. In one week observation 75 cases showed any symptoms of allergy including eruption and exacerbation of atopic eczema in an immediate, late, and/or delayed responses. Frequency of positive egg white-induce IL-2 responsiveness test in patients with positive oral provocation was 90.7% (68 out of 75 cases; sensitivity). That of negative test in patients with negative provocation was 84.0% (42 out of 50 cases; specificity). In contrast, specificity of IgE RAST for egg white were 88.0% comparable to the value of antigen-specific IL-2 responsiveness (AIR) test, but the specificity was lower value (37.3%) for screening the etiological antigens as compared to that of AIR test. High frequency of positive egg white-induced IL-2 responsiveness test was observed over an immediate, late and delayed responses, while low frequency of positive IgE RAST for hen egg was observed largely in patients showing delayed but not immediate response. The results indicate that IgE RAST in this study reflects IgE-mediated immediate type hypersensitivity, whereas AIR test reflects, in addition to immediate responses, late and delayed type hypersensitivity. The combined results suggest that AIR test in hen egg allergy is a useful method in vitro for both screening and determining etiological allergens, and might be able to substitute for provocation test in vivo for which many times, labours, expenses, and patients' risks are required, and to cover IgE RAST which fails to determine etiological allergens in 62.7% of patients with positive oral provocation.

Effect of glycated collagen on proliferation of human smooth muscle cells in vitro

While non-enzymatic glycation of long-lived tissue proteins such as collagen has been implicated in chronic complications of diabetes mellitus, its role in the aetiology of diabetic macroangiopathy has not been elucidated. To test the hypothesis that glycation of collagen abolishes the inhibitory effect of native collagen on the proliferation of human smooth muscle cells, we obtained smooth muscle cells from human gastric arteries and cultured them on dishes coated with glycated or non-glycated collagen. The proliferation of human smooth muscle cells in the presence of 10% fetal calf serum or platelet derived growth factor-BB (10 ng/ml) was inhibited by type 1 collagen coated on the dishes. Glycation of collagen with glucose 6-phosphate for 7 days abolished the growth-inhibitory effect of native collagen. Succinylation of collagen, which like glycation blocked the lysyl residues in collagen, also abolished the growth-inhibitory effect. Adhesion of human smooth muscle cells to collagen-coated dishes was not affected by glycation of collagen. Addition of glycated albumin to the medium did not affect the growth of human smooth muscle cells on plastic dishes. The inhibition of human smooth muscle cell proliferation by collagen was not reversed by the glycation of collagen in the presence of aminoguanidine. Results suggest that early glycation abolishes the inhibitory effect of collagen on human smooth muscle cell proliferation and may thus participate in the progression of macro-angiopathy in diabetes.

Modeling and analysis of spatio-temporal change in [Ca2+]i in a retinal rod outer segment

The change in [Ca2+]i, in a retinal rod outer segment to flash and step stimuli was simulated. The present model included inward and outward calcium fluxes through cation channels and an Na-Ca-K exchanger, respectively, calcium buffers, and diffusion through the interdiskal space of cytoplasm and incisures. Under control conditions (with the diffusion constant for calcium (DCa) of 10(-10) m2/s and the total concentration ([B]t) of 240 microM) the decrease in [Ca2+]i to flash stimuli was found to be localized around the edge of a disk irrespective of the presence or absence of incisures. Homogeneous but limited degree of decrease in [Ca2+]i was seen under a larger DCa of 10(-9) m2/s with no incisure. For the step illumination by which all the cation channels on a plasma membrane were closed, the decrease in [Ca2+]i around the edge of a disk was quick, while that at the center of an interdiskal space was slow (50% of the resting level at 5 s after the onset of the step illumination). These results indicate that the calcium feedback on guanylate cyclase and possibly on S-modulin in response to flash stimuli proceeds only around the edge of disk membranes or on the plasma membrane. This implicates localized mechanisms for the signal transduction and early phase of adaptation within rod outer segments.

Interactions and properties of smooth muscle myosin phosphatase

Interactions of the type 1 phosphatase catalytic subunit (PP1c) and the myosin phosphatase holoenzyme (MBP) were compared using affinity columns. In the absence of ATP, MBP bound to dephosphorylated myosin, heavy meromyosin (HMM), and subfragment 1. In contrast, PP1c was not bound. In the presence of ATP, the binding of MBP occurred only with phosphorylated protein. The interaction of MBP with phosphorylated proteins also was demonstrated using thiophosphorylated proteins as competitive inhibitors. Kinetics parameters were determined. With phosphorylated light chains (P-LC20), the major difference between PP1c and MBP was a lower K(m) for the latter. With myosin, MBP showed a marked increase in kcat, compared to PP1c. ATP did not affect these parameters. To investigate the role of the large phosphatase subunit, two recombinant proteins representing the N-terminal two-thirds of the molecule were expressed. These activated PP1c, and activation was maximum at approximately an equimolar ratio. The equimolar mixture of recombinant fragment and PP1c exhibited K(m) values similar to MBP and increased kcat values, compared to PP1c alone. An affinity column was prepared using the recombinant fragment. Phosphorylated HMM and P-LC20 were bound in the presence and absence of ATP. The interaction of P-LC20 was not ATP-dependent. Dephosphorylated HMM did not bind in the presence of ATP. The N-terminal fragment of the large subunit also contained a binding site for PP1c. These results indicate that the N-terminal portion of the large subunit of MBP contained binding sites for P-LC20 and PP1c.

Adoptive immunotherapy with tumor-specific T lymphocytes generated from cytokine gene-modified tumor-primed lymph node cells

Adoptive immunotherapy with immune T cells mediates regression of established tumors in animal models. We previously demonstrated that precursor lymphocytes of sensitized T cells can develop into mature effector cells after in vitro activation with anti-CD3 mAb and IL-2. We demonstrate here that tumor cells genetically modified to secrete IL-2 can enhance the precursor response in the tumor-bearing host and subsequently augment the antitumor efficacy of adoptive immunotherapy. MCA205 and MCA203, weakly immunogenic fibrosarcomas, were transfected in vitro with cDNA encoding for IL-2, IL-4, or IL-6. Lymph nodes (LN) draining these cytokine-producing tumors for 7 days were harvested, activated in vitro with anti-CD3/IL-2, and adoptively transferred into mice bearing established parental MCA205 pulmonary metastases. The effector cells generated from LN draining the IL-2 producing tumor exhibited enhanced antitumor activity compared with cells from LN draining parental, IL-4-producing, or IL-6-producing tumor. Phenotype analysis of cells from LN draining the IL-2-producing tumor revealed selective expansion of V beta 8+ cells. Depletion of V beta 8+ effector cells abrogated the antitumor efficacy indicating that V beta 8+ cells constituted the majority of antitumor reactivity and that secretion of IL-2 from tumor cells promoted the priming of V beta 8+ precursor cells, which can develop into mature effector cells. These results have important clinical implications that the method presented here could be applicable to the treatment of human cancer as more effective immunotherapy.

Adoptive immunotherapy with tumor-specific T lymphocytes generated from cytokine gene-modified tumor-primed lymph node cells

Adoptive immunotherapy with immune T cells mediates regression of established tumors in animal models. We previously demonstrated that precursor lymphocytes of sensitized T cells can develop into mature effector cells after in vitro activation with anti-CD3 mAb and IL-2. We demonstrate here that tumor cells genetically modified to secrete IL-2 can enhance the precursor response in the tumor-bearing host and subsequently augment the antitumor efficacy of adoptive immunotherapy. MCA205 and MCA203, weakly immunogenic fibrosarcomas, were transfected in vitro with cDNA encoding for IL-2, IL-4, or IL-6. Lymph nodes (LN) draining these cytokine-producing tumors for 7 days were harvested, activated in vitro with anti-CD3/IL-2, and adoptively transferred into mice bearing established parental MCA205 pulmonary metastases. The effector cells generated from LN draining the IL-2 producing tumor exhibited enhanced antitumor activity compared with cells from LN draining parental, IL-4-producing, or IL-6-producing tumor. Phenotype analysis of cells from LN draining the IL-2-producing tumor revealed selective expansion of V beta 8+ cells. Depletion of V beta 8+ effector cells abrogated the antitumor efficacy indicating that V beta 8+ cells constituted the majority of antitumor reactivity and that secretion of IL-2 from tumor cells promoted the priming of V beta 8+ precursor cells, which can develop into mature effector cells. These results have important clinical implications that the method presented here could be applicable to the treatment of human cancer as more effective immunotherapy.

Human beta2-glycoprotein I as an anticardiolipin cofactor determined using mutants expressed by a baculovirus system

beta2-Glycoprotein I (beta2-GPI) consists of five repeats of a homologous domain. We designed a series of human beta2-GPI mutant genes, ie, three mutant genes lacking the domain(s) present in the NH2-terminal region and two of those present in the COOH-terminal region. These mutant genes were expressed in Spodoptera frugiperda insect cells (Sf9) infected with recombinant baculoviruses and the mutant proteins were secreted into the culture medium. The molecular mass of the purified mutant proteins, estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was fairly consistent with the size calculated from their nucleotide sequences. Binding of beta2-GPI to solid-phase cardiolipin (CL) was diminished by the deletion of the fifth domain (domain V) from its complete structure. Thus, the phospholipid binding site of beta2-GPI is located on its domain V. Monoclonal anti-CL antibodies (aCL) derived either from NZW x BXSB (WB) F1 mice or from patients with antiphospholipid syndrome bound directly to the domain V-deleted mutant protein (DI-IV) absorbed not only on an oxygenated but also on a plain polystyrene surface. We conclude from this study that the epitope for aCL is exposed on a conformationally changed structure of beta2-GPI by interacting with negatively charged phospholipid or on the mutant protein, DI-IV.

Tranilast suppresses intimal hyperplasia in the balloon injury model and cuff treatment model in rabbits

Intimal hyperplasia is a serious problem after percutaneous transluminal coronary angioplasty (PTCA). In this study, we investigated the effects of tranilast on intimal hyperplasia in both in vivo and in vitro experiments. For the in vivo experiments, we used the balloon injury model and the cuff treatment model of rabbits fed regular chow. In the balloon injury model, tranilast decreased intimal area, intima/media ratio, stenosis ratio and vascular DNA content after endothelial injury. Also in the cuff treatment model, tranilast suppressed the intimal hyperplasia. In the in vitro experiments, we assessed the effects of tranilast on platelet-derived growth factor-induced rabbit vascular smooth muscle cell (VSMC) migration and proliferation and on collagen synthesis by VSMCs. Tranilast inhibited VSMC migration, proliferation and collagen synthesis. These results suggest that tranilast has a suppressive effect on intimal hyperplasia after a vascular injury such as PTCA.

The localization of tissue factor and apolipoprotein(a) in atherosclerotic lesions of the human aorta and their relation to fibrinogen-fibrin transition

We examined the immunohistochemical distribution of tissue factor (TF), apolipoprotein (a) (apo(a)) in atherosclerotic intimas of human thoracic aortas obtained from 51 autopsies in order to analyze the mechanism of fibrinogen-fibrin transition as a part of thrombogenic properties of atherosclerotic intimas. TF was overexpressed mainly by macrophages in both fatty streaks and more advanced lesions, while it was also scatteringly deposited in the matrix of advanced lesions, especially in the atheromatous gruel. TF-positive macrophages were frequently intermingled at the base of fibrin thrombi formed on the eroded intimas. On the other hand, apo(a) was localized in the stroma and within some macrophages, and also in the mural thrombi. Fibrinogen and fibrin were more frequently detected in the matrix of advanced lesions than in that of early lesions. Fibrin was occasionally co-located with cell- and matrix-associated TF and apo(a) deposited in matrix. These findings suggest that the overexpressed TF in the atherosclerotic intima plays a critical role in the initiation of fibrin formation. This could result from either fibrinogen permeating into the intima or from rupture of the fibrous cap overlying atheromas. Apo(a) deposited in the atherosclerotic intima may also participate in the persistent deposition of fibrin.

Phosphorylation of the large subunit of myosin phosphatase and inhibition of phosphatase activity

The partially purified myosin-bound phosphatase had an associated protein kinase that phosphorylated the holoenzyme, primarily on the large (130-kDa) subunit. Phosphorylation of the 130-kDa subunit resulted in inhibition of phosphatase activity. The major site of phosphorylation was threonine 654 of the 130-kDa subunit or threonine 695 of the 133-kDa isoform. Phosphorylation of the large subunit did not dissociate the holoenzyme. Dephosphorylation of the large subunit was achieved by the holoenzyme, and addition of the catalytic subunit of the type 2A enzyme did not increase the rate of dephosphorylation. The associated kinase was inhibited by chelerythrine, with half-maximal inhibition at approximately 5 microM (in 150 microM ATP). The associated kinase phosphorylated two synthetic peptides, one corresponding to the sequence flanking the phosphorylated threonine, i.e. 648-661 of the 130-kDa subunit, and the other to a known protein kinase C substrate, i.e. a modified sequence from the autoinhibitory region of epsilon protein kinase C. The associated kinase was activated by arachidonic and oleic acid and to a lesser extent by myristic acid. The protein kinase that phosphorylated the 130-kDa subunit and resulted in inhibition of myosin phosphatase activity was not identified.

T cell mediation of abnormally low production of ovalbumin-specific immunoglobulin A in patients allergic to eggs

Cells producing IgA specific to ovalbumin (OVA) were detected with an assay of plaque-forming cells (PFC). Non-T cells were separated on a polystyrene resin column and were further depleted of B cells that bound sheep erythrocytes (SRBC) by SRBC-rosette sedimentation. The cells were recombined with T cells separated on a polystyrene resin column, stimulated with OVA antigen, and then cultured for 5 d. The number of OVA-specific IgA-PFC from the lymphocytes of infants allergic to hen's eggs (7 +/- 5 per 7 x 10(4) non-T cells, n = 9) was significantly less than that of PFC from lymphocytes of age-matched controls (110 +/- 18 per 7 x 10(4) non-T cells, n = 7) and from those of children with atopic dermatitis who were not allergic to hen's eggs (90 +/- 30 per 7 x 10(4) non-T cells, n = 4). Patients' B cells added to the culture supernatant from OVA-stimulated normal T cells (82 +/- 18 per 7 x 10(4) non-T cells, n = 4) were able to produce the specific IgA to levels comparable to those of normal B cells (92 +/- 9 per 7 x 10(4) non-T cells, n = 6), but the patients' T cells did not cause normal B cells to produce the antibody (8 +/- 2 per 7 x 10(4) non-T cells, n = 4). This indicates that the patients' T cells were less able than were normal T cells to promote the production of OVA-specific IgA-PFC. Until the age of 6 y, the ability of the patients' lymphocytes to produce specific IgA was abnormally low; from that age on, it was normal. At the stage of allergen entry, this transiently low production of OVA-specific IgA may contribute to the onset of allergy to hen's eggs.

Effects of monoclonal anticardiolipin antibody on pregnant mice

OBJECTIVE

To clarify the effects of anticardiolipin antibodies (aCL) on pregnancy.

METHODS

Monoclonal aCL obtained from MRL/lpr mice was administered to pregnant BALB/c mice and changes in the outcome of pregnancy were evaluated.

RESULTS

The pregnant BALB/c mice injected with monoclonal aCL showed a higher intrauterine fetal death rate than controls, but there were no significant differences in platelet counts. We observed signs of placental infarction only in the placenta of the treated pregnant BALB/c mice.

CONCLUSION

The intrauterine fetal deaths may have been due to thrombosis.

Association between a polymorphism in the angiotensin-converting enzyme gene and microvascular complications in Japanese patients with NIDDM

The relationship between diabetic nephropathy and an insertion (I)/deletion (D) polymorphism in intron 16 of the angiotensin-converting enzyme (ACE) gene is still under debate. The association of ACE gene polymorphism with nephropathy and retinopathy was therefore examined in 362 Japanese patients with non-insulin-dependent diabetes mellitus (NIDDM) and 105 healthy control subjects. Distribution of the ACE genotype did not differ between healthy control subjects and diabetic patients without complications. However, the frequency of the D allele was significantly higher in the diabetic subjects with nephropathy than in those without (0.32 in normoalbuminuric patients vs 0.44 in albuminuria patients with albuminuria) (chi 2 = 7.7; p = 0.006). There was no significant association between ACE genotype and retinopathy. These observations thus demonstrate a significant association of the ACE gene polymorphism with nephropathy, but not with retinopathy, in Japanese patients with NIDDM.

Effects of low molecular weight heparin on a severely antithrombin III-decreased disseminated intravascular coagulation model in rabbits

The effect of dalteparin, a low molecular weight heparin, on severely antithrombin III (ATIII)-decreased disseminated intravascular coagulation (DIC) model was compared with that of unfractionated heparin (heparin). The DIC model in rabbits was produced by continuous infusion of thrombin in combination with bolus injection of latex. After a 3 hr infusion of thrombin, plasma ATIII activity was lowered to 30% of normal plasma. Platelet number, fibrinogen content and alpha 2 plasmin inhibitor (alpha 2PI) activity were also decreased. Dalteparin (25-100 IU/kg/hr) and heparin (25-100 U/kg/hr) inhibited the decrease in ATIII activity, platelet number and fibrinogen content, and had no effect on alpha 2PI activity. Activated partial thromboplastin time (APTT) was prolonged by heparin (50 and 100 U/kg/hr), but not by dalteparin (25-100 IU/kg/hr). The ratio of anti-factor Xa (F.Xa) activity to anti-thrombin activity for dalteparin (50 IU/kg/hr) was higher than that for heparin (50 U/kg/hr). With the addition of exogenous ATIII, the ratio of anti-F.Xa to anti-thrombin for heparin increased, but that for dalteparin did not change. However, the increased ratio for heparin was still lower than the unchanged ratio for dalteparin. These results suggest that both dalteparin and heparin have the ability to rectify the abnormal parameters of severely ATIII-decreased DIC, and that the effects of dalteparin are mainly involved with anti-F.Xa activity whereas the effects of heparin are via anti-thrombin activity.

Differences in cellular transport of tri-iodothyronine and thyroxine: cell cycle-dependent alteration of tri-iodothyronine uptake

Cellular and nuclear uptake of tri-iodothyronine (T3) and thyroxine (T4) was examined using the cultured cell line derived from rat liver, clone 9, and rat hepatoma, dRLH-84. The saturable cellular uptake of T3 and T4 was demonstrated in these cells. First we examined the cell cycle-dependent alteration of thyroid hormone uptake. Cellular T3 uptake was minimal in the early G1 phase and increased in the late G1 phase, reaching a maximal level in the S phase. Alterations in nuclear T3 uptake were in accordance with the changes in cellular T3 uptake. On the other hand, cellular and nuclear T4 uptake was unchanged throughout the cell cycle, suggesting the T3 specificity of the cell cycle-dependent alteration of cellular hormone transport. Next we examined the effect of sodium butyrate on the cellular transport of thyroid hormones. After treatment with 5 mM sodium butyrate, cellular and nuclear uptake of T3 was increased, reaching a maximal level (four- to sevenfold increase) after 48 h. When cells were incubated for 48 h with various concentrations of sodium butyrate, T3 uptake was enhanced by 1 mM sodium butyrate, reaching a maximal level with 5 mM. Although cellular T4 uptake was also increased after treatment with sodium butyrate, the degree and time-course of the increase were different from those of T3. The maximal increase in cellular T4 uptake (two- to threefold increase) was attained 20 h after treatment. Despite the increase in cellular T4 uptake, nuclear T4 uptake was decreased after treatment with sodium butyrate. For both T3 and T4, the enhanced cellular uptake was due to the increased Vmax without changes in the Michaelis-Menten constant. These data indicate that cellular transport of T4 is different from that of T3 in rat hepatic cells.

In vivo ESR measurements of free radical reactions in living mice

In vivo ESR measurements were carried out to estimate free radical reactions in living mice using nitroxyl radicals as probes. The ESR signal of nitroxyl radical which was intravenously or intramuscularly injected to living female ddY mice decreased gradually by reducing to the corresponding hydroxylamine. The reduction rate was enhanced by oxidative stress, and pre-treatment of antioxidants suppressed the enhancement of signal decay. Oral administration of carbon tetrachloride enhanced signal decay in upper abdomen but not in thorax. These results indicated that free radicals, which can reduce nitroxyl radical, were produced in the upper abdomen by oral administration of carbon tetrachloride.

Influence of plasma lipoprotein (a) levels on coronary vasomotor response to acetylcholine

OBJECTIVES

This study was undertaken to examine the influence of plasma lipoprotein(a) [Lp(a)] levels on coronary endothelial vasomotor function.

BACKGROUND

Epidemiologic studies have demonstrated a direct relation between elevated plasma levels of Lp(a) and increased risk of coronary artery disease. Well recognized coronary risk factors are known to affect endothelium-dependent vasomotion; however, the influence of Lp(a) on coronary vasomotor function has not been determined.

METHODS

We used quantitative coronary angiography to measure left anterior descending coronary artery diameter changes produced by intracoronary acetylcholine and isosorbide dinitrate in 30 patients with angiographically normal coronary arteries. Plasma Lp(a) levels were determined with enzyme-linked immunosorbent assay.

RESULTS

Vasomotor response to acetylcholine ranged from +13% to -47% in the proximal, from +23% to -53% in the middle and from +13% to -56% in the distal segment of the left anterior descending coronary artery. According to univariate linear regression analysis, Lp(a) had a significant inverse correlation with vasomotor response to acetylcholine: r = 0.47, p < 0.01 in the proximal; r = -0.61, p < 0.001 in the middle; and r = -0.52, p < 0.01 in the distal segment of the left anterior descending coronary artery. By multiple stepwise regression analysis, plasma Lp(a) was the significant predictor of vasomotion in response to acetylcholine in all tested segments (p < 0.01).

CONCLUSIONS

Elevated Lp(a) levels were associated with impairment of endothelium-dependent vasodilation even when atherosclerotic lesions were not recognizable by angiography. This finding suggests that elevated plasma levels of Lp(a) cause endothelial dysfunction and may contribute in part to later development of atherosclerosis, as shown in epidemiologic studies.

Serotonergic cells in nucleus raphe pallidus provide tonic drive to posterior cricoarytenoid motoneurons via 5-hydroxytryptamine2 receptors in cats

Microinjection of serotonin and 5-hydroxytryptamine2 (5-HT2) agonist 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM) in nucleus ambiguus caused excitation of posterior cricoarytenoid (PCA) muscles of the larynx in anesthetized, spontaneously breathing cats. Intravenous administration of 5-HT2 antagonist ketanserin produced complete block of excitatory effect of DOM injection. Electrical stimulation of nucleus raphe pallidus caused excitation of PCA activity, that was blocked by pretreatment of ketanserin. These results indicate that serotonergic cells in the raphe pallidus provide tonic drive to medullary PCA motoneurons through 5-HT2 receptors.