Recombinant bovine conglutinin, lacking the N-terminal and collagenous domains, has less conglutination activity but is able to inhibit haemagglutination by influenza A virus

Conglutinin is a bovine serum protein which was first described as a vertebrate lectin. This protein belongs to the family of C-type lectins. These lectins are composed of four characteristic domains: (1) an N-terminal cysteine-rich domain, (2) a collagen-like domain, (3) a neck domain and (4) a carbohydrate recognition domain (CRD). Recently lectins have been shown to function as immunoglobulin-independent defence molecules due to a complement-mediated mechanism or opsonization. Our previous study showed that bovine conglutinin can inhibit haemagglutination by influenza A viruses and act by directly neutralizing them due to its lectin properties. In order to elucidate the biological role of the collagen-like domain, a recombinant partial conglutinin lacking this collagen-like domain was produced in an Escherichia coli system and its biological activities were examined. A 497 bp sequence, consisting of a short collagen region (two repeats of G-X-Y amino acid sequences), the neck domain, and the CRD of conglutinin cDNA, was amplified by the reverse-transcriptase PCR technique. The cDNA was transferred to a bacterial expression vector system (pRSET-A) and stable transfectants with a high level of conglutinin production were obtained. SDS/PAGE and Western blotting analyses showed a recombinant fusion protein of 27 kDa. Results of a cross-linking study and gel-filtration assay indicated that the recombinant conglutinin can form a trimeric structure and that it has sugar binding activity and specificity similar to that of native conglutinin. The recombinant conglutinin was also found to inhibit haemagglutination caused by influenza A virus as well as to possess less conglutination activity. These results suggest that in order for conglutinin to inhibit haemagglutination caused by the influenza virus, as well as to have sugar binding activity or to form trimers, it does not require the N-terminal and collagenous domains; however, they are essential for full conglutination activity.

Retrovirus-mediated suicide gene transduction in the vitreous cavity of the eye: feasibility in prevention of proliferative vitreoretinopathy

In proliferative vitreoretinopathy (PVR), retinal pigment epithelial cells, fibroblasts, or other proliferating cells form contractile membranes in the vitreous cavity of the eye, resulting in traction retinal detachment. Retroviral vector-mediated transfer is a suitable method to transduce the herpes simplex virus thymidine kinase (HSV-tk) gene into proliferating cells in PVR, allowing for the selective killing of these cells. To determine the potential of gene transduction in the environment of the vitreous cavity, we evaluated the effect of vitreous humor on retroviral vector-mediated gene transduction of rabbit dermal fibroblasts in vitro and studied in vivo transduction in rabbit experimental PVR with retroviral vector G1BgSvNa. In addition, we studied the bystander effect in vitro and in vivo in a rabbit model of PVR, with low percentages of HSV-tk-positive cells. Finally, we evaluated the efficacy of intravitreal administration of HSV-tk retroviral vector G1TkSvNa followed by ganciclovir (GCV) in the prevention of experimental PVR. Vitreous humor reduced gene transfer efficiency in vitro in a dose-dependent manner. LacZ expression was found in cells of preretinal or intravitreal membranes of animals of both in vivo and in vitro transduction groups; however, in vivo transduction resulted in a decreased number of transduced cells, with a relative transduction efficiency of approximately 2%. Transduction of HSV-tk was associated with a powerful bystander effect both in vitro and in vivo with significant effects even when HSV-tk-positive cells represented only 1% of the population. In vivo transduction with G1TkSvNa followed by GCV significantly inhibited the development of PVR (p < 0.05). These results suggest that retroviral vector-mediated transfer of HSV-tk into the proliferating cells in PVR may be feasible and may provide a novel therapeutic strategy for this disease.

Preoperative predictors of reduction in arterial blood pressure following dural opening during surgical evacuation of acute subdural hematoma

To determine preoperative predictors of blood pressure reduction following dural opening during surgical evacuation of hematoma, we retrospectively assessed preoperative variables including clinical profile, hemodynamic parameters, neurological findings, and computed tomography (CT) scan results in 56 patients with traumatic acute subdural hematoma (ASDH). Patients were divided into two groups according to the degree of changes in mean arterial pressure (MAP) in response to dural opening. Group A (n = 18) had a MAP reduction > 20%, and group B (n = 38) had a MAP change within +/- 20% of baseline values (5 min before opening the dura). Significant relationships were found between MAP reductions > 20% and Glasgow coma scale (GCS) scores, abnormalities of the mesencephalic cistern on CT scan, pupillary abnormalities, and degree of midline shift. Low GCS score, absence of the mesencephalic cistern on CT scan, and bilaterally dilated pupils were particularly strong predictors of this amount of blood pressure reduction. The clinical outcomes of patients with MAP reduction > 20% following dural opening during surgery were significantly poorer than those of patients without this amount of blood pressure reduction. Our findings suggest that blood pressure reduction following opening of the dura in patients undergoing surgical evacuation of hematoma for traumatic ASDH may be predicted by careful preoperative assessment of neurological and CT scan findings.

Molecular characterization of an adenylate cyclase gene of the cyanobacterium Spirulina platensis

A cyaA gene, encoding an adenylate cyclase, was isolated from a filamentous cyanobacterium, Spirulina platensis, by functional complementation of a cya mutant of Escherichia coli, defective in adenylate cyclase activity. The predicted gene product of cyaA contains a signal peptide-like domain, a putative sensor domain similar to the gene product of vsrA of Pseudomonas solanacearum, a putative membrane-spanning domain and an adenylate cyclase-like catalytic domain. Two other positive clones that complemented the E. coli mutant were isolated from the same cyanobacterium, suggesting that several cya genes are functioning in S. platensis.

Reconstruction of the mitral annulus with porcine pericardium--report of a case with mitral annular disruption due to staphylococcal endocarditis

A 60-year-old man was admitted to our hospital for investigation of dyspnea and disorientation with right hemiplegia. Echocardiography showed thickened mitral valve leaflets with vegetations and severe mitral regurgitation. Blood cultures grew Staphylococcus aureus. During the operation, perforation and destruction of the mitral valve leaflets and vegetations were confirmed. Debridement of the infected tissues resulted in segmental disruption of the posterior mitral fibrous annulus. Reconstruction of the mitral annulus with porcine pericardium treated with glutaraldehyde and mitral valve replacement were successful. The patient's postoperative course was complicated with metastatic cerebral and splenic abscesses. After splenectomy on the 8th postoperative day, he gradually recovered without major neurologic sequelae. We believe that reconstruction of the mitral valve annulus with pericardium, especially autologous pericardium, is reliable and useful for the treatment of patients with disruption of the mitral valve annulus.

Modulation of cell death pathways to apoptosis and necrosis of H2O2-treated rat thymocytes by lipocortin I

Lipocortin I, also called annexin I, a calcium and phospholipid binding protein, protected rat thymocytes from H2O2-elicited necrosis and facilitated H2O2-induced apoptosis, while anti-lipocortin I antibody enhanced H202-elicited necrosis by blocking H202-induced apoptosis. Essentially similar results were obtained with phospholipase A2 inhibitors and activators such as 3,4-octyadecyl-benzylacrylic acid and melittin, respectively. Available evidence suggests that lipocortin I modulates signals for cell death pathways of H2O2-treated rat thymocytes to apoptosis and necrosis by regulating cellular phospholipase A2 activities but not by inhibiting membrane lipid peroxidation.

Induction of proteins in response to cold acclimation of rainbow trout cells

The in vitro translation of poly(A)-RNA isolated from control and cold-treated cells showed that low temperatures induced changes in the population of translatable mRNAs. When cellular proteins extracted from cold-treated cells were subjected to two-dimensional gel electrophoresis, the 70 kDa protein was found to be synthesized during the cold treatment. N-terminal sequence analysis showed that the 70 kDa cold-inducible protein was a homolog of the mammalian valosin-containing protein and yeast CDC48p. The changes in mRNA and protein contents during cold acclimation may result from the expression of genes involved in the adjustment of cellular metabolism to low temperature or the induced proteins may be directly involved in the cold acclimation.

Role of bradykinin B2 receptors and mast cells in the bradykinin-induced skin response in the rat

We investigated the role of activation of bradykinin receptors and mast cells in the microvascular leakage of the vessels of the skin induced by the intracutaneous (i.c.) injection of bradykinin in the rat. We evaluated the effects of HOE140 (D-Arg-[Hyp3,Thi5,D-Tic7,Oic8]bradykinin), a bradykinin B2 receptor antagonist, and ketotifen (4-(1-methyl-4-piperidylidene)4H-benzo[4,5]cyclohepta[1, 2-b]thiophen-10(9H)-one hydrogen fumarate), a histamine H1 receptor antagonist with mast cell stabilizing properties, on the skin response. Evans blue dye extravasation served as an index of the increase in vascular permeability. Bradykinin (2-100 nmol/site i.c.) induced the extravasation of Evans blue dye in a dose-dependent manner. Ketotifen (20 mg/kg i.p.) significantly inhibited the leakage of dye induced by bradykinin (10 nmol/site i.c.) by 66.2%, while HOE140 (1 mg/kg i.v.) had no effect. The concomitant injection of HOE140 (0.2, 2 nmol/site) and bradykinin (10 nmol/site i.c.), also did not significantly reduce the extravasation of dye. We conclude that the extravasation of plasma induced by the i.c. injection of bradykinin is mediated mainly by stimulation of the skin mast cells, but not by bradykinin B2 receptors.

Vitamin E succinate inhibits proliferation and migration of retinal pigment epithelial cells in vitro: therapeutic implication for proliferative vitreoretinopathy

BACKGROUND

Retinal pigment epithelial (RPE) cells play an important role in proliferative vitreoretinopathy (PVR). Vitamin E succinate is an ester form of a potent biological antioxidant, vitamin E, and has unique effects on various cells. We examined the effect of vitamin E succinate on proliferation and migration of cultured bovine RPE cells, since these are critical steps in the development of PVR.

METHODS

Bovine RPE cells were cultured in minimal essential medium (MEM) containing 10% fetal calf serum (MEM-10). Cells were incubated with MEM-10 containing 25 microM vitamin E, vitamin E succinate, butylated hydroxytoluene (BHT) or d-mannitol. Cell proliferation was assessed by counting cell numbers on days 2, 4 and 6. 3H-Thymidine uptake was also examined in RPE cells incubated with various forms of vitamin E-- vitamin E, vitamin E succinate, Trolox, gamma-tocopherol, vitamin E acetate, vitamin E phosphate, vitamin E nicotinate--or antioxidants-- BHT or d-mannitol (25 microM each). RPE cell migration was studied as follows: A small area (5 x 15 mm) of confluent cultured RPE cells was denuded using a straight razor blade and incubation was continued for 20 h with MEM-10 containing vitamin E, vitamin E succinate, gamma-tocopherol or BHT. The number of cells that migrated into the denuded area from the wound edge in each microscopic field (x20) was counted and expressed as a percentage of control (MEM-10 alone).

RESULTS

The antioxidants, vitamin E and BHT, stimulated RPE cell proliferation and 3H-thymidine incorporation compared with the control, while vitamin E succinate significantly inhibited both proliferation and 3H-thymidine uptake (IC50, 23 microM). Other forms of vitamin E or d-mannitol had no effect. Neither vitamin E nor BHT had a significant effect on RPE cell migration (108.2% and 112.6% of control, respectively), but vitamin E succinate inhibited migration (58.3%). Cell viability, assessed by the trypan blue dye exclusion test, was not impaired by a 3-day incubation with 50 microM of vitamin E succinate.

CONCLUSIONS

An ester form of a physiological antioxidant, vitamin E succinate, inhibits RPE cell proliferation and migration without causing cellular toxicity. These findings suggest its therapeutic potential for the pharmacological treatment of PVR.

Effect of hyperthermia on proliferation and deviation of carcinoembryonic antigen and squamous cell carcinoma-related antigen of human esophageal carcinoma cells in culture

As a basic study of hyperthermia on malignant tumors, we investigated the kinetics of proliferative activity and the values of tumor markers carcinoembryonic antigen (CEA) and squamous cell carcinoma-related antigen (SCC) in a human esophageal carcinoma cell line, SGF-4, following a change of culture temperature. The temperature range allowing cultured SGF-4 cells to proliferate was from 37 degrees C to 40 degrees C. In an experiment examining the recovery of proliferative activity, no proliferative activity was observed after the cultured cells were exposed to 42 degrees C for 72 hours. The values of CEA and SCC as tumor markers were found to be increased in association with the cell damage due to the change of temperature. These markers could thus be useful as indicators for evaluations of hyperthermia therapy effectiveness.

Simplified technique for hemi-arch replacement during open distal anastomosis: the "calla" method

During open distal anastomosis for type A dissecting aneurysm, the beveled end of the graft was rolled back like a bract of the Calla flower and inserted into the aortic lumen. The inverted graft was anastomosed using forehand continuous sutures. After completion of the distal anastomosis, the inverted graft was pulled out and then the proximal anastomosis was completed. This "Calla flower" deformation facilitates the hemostatic distal anastomosis in hemi-arch replacement during open distal anastomosis.

Hypericin inhibits cell growth and induces apoptosis in retinal pigment epithelial cells: possible involvement of protein kinase C

Proliferative vitreoretinopathy (PVR) is characterized by the proliferation and migration of retinal pigment epithelial (RPE) cells in the vitreous cavity. The drug hypericin, which is already in clinical use as an antidepressant, has shown promise as an antiviral and antineoplastic agent. To investigate the therapeutic potential of hypericin in PVR, we incubated RPE cells in standard medium with various serum concentrations containing 0.5 to 5 microM hypericin. In some experiments we studied the effects of hypericin in conjunction with the RPE growth stimulating cytokine tumor necrosis factor alpha (TNF-alpha). Dose-dependent inhibition of RPE cell proliferation with IC50 values of 0.7 microM and 3.3 microM in 1% and 5% serum respectively, was found. Even in conjunction with TNF-alpha, hypericin inhibited RPE proliferation with an IC50 value of 1.5 microM. The drug inhibited PKC activity in cells treated with a 2.5 microM dose by 72% after 30 min and by 100% after 180 min. Finally, hypericin induced RPE cells to undergo apoptotic cell death, as shown by the presence of DNA laddering. These results suggest that hypericin may have potential as a therapeutic drug for PVR and that its antiproliferative and apoptotic effects on RPE cells in vitro are in part mediated by PKC.

Monitoring the native cardiac output during femoral venoarterial cardiopulmonary bypass support

To manage postcardiotomy patients with cardiopulmonary bypass support (CPS), it is very important to evaluate the native cardiac function. In 5 postcardiotomy cases without CPS, the alternative thermodilution outputs by right ventricular (RV) injection were compared with simultaneous thermodilution outputs by standard right atrial (RA) injection. Cardiac output determined by RV injections, ranging from 3.4 to 10.1 L/min, showed close agreement with the values by RA injections (r = 0.993). Four cases with postcardiotomy profound heart failure were placed on femoral venoarterial CPS and managed with monitoring native cardiac output determined by an RV injection thermodilution method. It was very easy and reasonable to decide the pump flow relative to native cardiac output. The cardiac output determined by RV injection provides a means of accurate evaluation for the failing heart in postcardiotomy cases with venoarterial CPS and optimizes the staged weaning off CPS or the change to a pneumatic pulsatile ventricular assist device for long-term assist.

Changes of intraaortic balloon volume during pumping in a mock circulation system

The effects of hemodynamic changes on intraaortic balloon (IAB) volumes were studied experimentally using a helium tachometer in a mock circulatory system. The IAB volume decreased with increases in the heart rate and mean aortic pressure, but the degree of reduction in the IAB volume was different among 4 commercially available IAB drivers. Improvements in IAB consoles are needed to compliment the progress made in percutaneous techniques for IAB insertion resulting in smaller balloons.

Comparison of in vitro antiproliferative effects of steroids and nonsteroidal antiinflammatory drugs on human keratocytes

Corticosteroids are currently administered after photorefractive keratectomy (PRK) to reduce corneal haze and myopic regression, However the beneficial effects of corticosteroids are controversial, and they are associated with many side effects. In this study we compared the in vitro antiproliferative effects of nonsteroidal antiinflammatory drugs (NSAIDs), diclofenac and flurbiprofen, with those of dexamethasone on human keratocytes. Human keratocytes were incubated with various concentrations of diclofenac, flurbiprofen, and dexamethasone. The control samples were incubated under the same conditions except for the absence of drugs. Proliferation of the keratocytes was measured by [3H]thymidine uptake into DNA on days 1, 2, and 4. Diclofenac was the most potent agent, inducing dose-dependent inhibition at concentrations > or = 10(-1) mM on days 1 and 2 and > or = 10(-5) mm on day 4. Flurbiprofen followed closely, inhibiting keratocytes at and above 1 mm on day 1, 10(-1) mm on day 2, and 10(-4) mm on day 4. Dexamethasone was the least effective, exhibiting inhibition at and above 25 mM on day 1, 5 mM on day 2, and 1 mM on day 4 (Wilcoxon rank sum test, P < or = 0.05). The ID50S reflect the same trend (day 4: diclofenac = 0.03 mM, flurbiprofen = 0.2 mM, dexamethasone = 3.2 mM). In addition, diclofenac and dexamethasone showed time-dependent antiproliferative effects. These results indicate that NSAIDs are more potent than corticosteroids in inhibiting proliferation of human keratocytes in vitro, and suggesting a potential use of NSAIDs in modulating corneal wound healing after PRK.

Histologic findings and prognosis of uveal malignant melanoma in japanese patients

PURPOSE

To determine factors of uveal malignant melanoma that would help to predict prognosis in Japanese patients.

METHODS

From 1969 to 1994, 23 eyes with uveal malignant melanoma were enucleated from 23 Japanese patients, and 16 of these patients were studied. In the 16 patients, enucleated eyes were evaluated for tumor characteristics, including cell type and microvascular architecture. Patient records were reviewed for follow-up therapy and outcome. Mortality rate was evaluated four years after enucleation.

RESULTS

In Japanese patients with uveal malignant melanoma, the average tumor size was larger (average largest diameter, 11.36 mm; average increase, 6.25 mm) and the average patient age was younger (55.2 years old) than previously reported for white populations. Patients with spindle cell type melanoma tended to have a better prognosis than those with epithelioid cell type (four-year mortality rates: spindle cell type, 0%; mixed cell type, 43%; epithelioid cell type, 66%). Microvascular architecture patterns interpreted as either network or closed loop patterns were associated with a poorer prognosis (network pattern, P = .03; closed loop pattern, P = .005).

CONCLUSIONS

The prognosis for Japanese patients with uveal malignant melanoma is poorer, and epithelioid cell-type melanoma is more common, than has been reported in white populations. Mitotic figures are well correlated with poor prognosis, as are two microvascular patterns, the network pattern and the closed loop pattern.

Lack of a role for bradykinin in allergen-induced airway microvascular leakage and bronchoconstriction in the guinea pig

We have investigated the role of bradykinin in allergen-induced airway microvascular leakage and bronchoconstriction in sensitized guinea pigs. We used a selective bradykinin B2 receptor antagonist, HOE140, which has been shown to prevent the airway effects induced by bradykinin. Lung resistance (RL) was measured for 6 min after challenge with allergen. Extravasation of Evans blue dye into airway tissues was used as an index of the airway microvascular leakage. Aerosolized ovalbumin (5 mg/ml, 30 breaths) induced a significant increase in RL and leakage of dye in the trachea, main bronchi and intrapulmonary airways in the ovalbumin-sensitized guinea pigs. HOE140 given by inhalation (200 microM, 60 breaths) had no effect on the airway microvascular leakage and bronchoconstriction induced by the allergen. I.v. HOE140 (200 nmol/kg) did not significantly inhibit these airway responses. We conclude that bradykinin-mediated mechanism may not play a significant role in airway microvascular leakage or bronchoconstriction induced by allergen.

Effects of right ventricular failure on renal function during pneumatic left ventricular assist

In an experiment dog model of acute biventricular failure, the effects of left ventricular (LV) assist on renal hemodynamics and function were evaluated. After the induction of severe cardiac failure by multiple ligation of the coronary arteries, LV assist with a 40 ml pneumatic pulsatile pump was initiated, and the aortic flow was maintained at control values. The right atrial pressure (RAP) rose to 21.3 mm Hg with the appearance of profound right ventricular (RV) failure. Renal arterial blood flow (RAF) decreased to about 60% of the control value after 2 h of LV assist. The urine volume decreased and renal function deteriorated progressively. RV assist decreased the RAP to 4.8 mm Hg, and the reduced RAF recovered. After 3 h of RV assist, the RAF returned to initial values and the urine volume increased, but renal function did not recover. Advanced biventricular failure with elevated RAP during LV assist reduced renal perfusion and impaired renal function and may be an indication for early RV assist.

Hair analysis for drugs of abuse XII. Determination of PCP and its major metabolites, PCHP and PPC, in rat hair after administration of PCP

We developed an analytical method for the simultaneous detection of phencyclidine (PCP) and its metabolites, 4-phenyl-4-piperidinocyclohexanol (PPC) and 1-(1-phenylcyclohexyl)-4-hydroxypiperidine (PCHP), in rat hair. Three pigmented, hairy rats were intraperitoneally administered PCP hydrochloride (HCl) at 0.05-0.5 mg/kg once a day for 10 successive days. Animal hair was shaved just before the first administration, and the newly grown hair was collected 4 weeks after the first administration. After the rat hair sample was washed three times with 0.1% sodium dodecyl sulfonate and water, separately, and dried in a desiccator, 20 mg of finely cut hair was extracted with 2 mL methanol-5N HCl (20:1) under ultrasonication for 1 h, followed by storage at room temperature for 14 h. Following filtration and evaporation of the extract, it was purified with Bond Elut Certify in the usual manner, and the extract was derivatized with N,O-bis(trimethylsilyl) acetamide for gas chromatographic-mass spectrometric analysis using deuterated PCP, PPC, and PCHP as internal standards. The selected ions were monitored at m/z 186, 200, and 242 for PCP, m/z 172, 288, and 331 for trimethylsilyl (TMS) PCHP, and m/z 200, 254, and 331 for TMS PPC. PCP, PCHP, and PPC were simultaneously detected in the rat hair down to 0.1 mg/kg PCP HCl. Even at the dose of 0.05 mg/kg, PCP was clearly detected in the rat hair. Based on the area under the concentration versus time curve (AUC) in plasma (1460 ng.min/mL), the PCP concentration (3.34 ng/mg) in the rat hair was quite high. The incorporation rates into hair (concentration in hair/AUC) of PCP, PCHP, and trans-PPC were 2.29, 1.65, and 0.50, respectively, at 0.5 mg/kg. Our results suggest that hair could be a useful specimen for confirmation of active past PCP use because PCP and its metabolites can be detected simultaneously.

Intraoperative myogenic motor evoked potentials induced by direct electrical stimulation of the exposed motor cortex under isoflurane and sevoflurane

We monitored myogenic motor evoked potentials (MEPS) during intracranial surgery in 21 patients anesthetized with nitrous oxide in oxygen, fentanyl, and 0.75-1.5 minimum alveolar anesthetic concentration (MAC) isoflurane (n = 11) or sevoflurane (n = 10). The exposed motor cortex was stimulated with a single or train-of-five rectangular pulses at a high frequency (500 Hz), while the compound muscle action potentials (CMAPS) were recorded from the abductor pollicis brevis muscle. Neuromuscular block was monitored by recording the CMAPs from the abductor pollicis brevis muscle in response to electrical stimulation of the median nerve at the wrist (M-response). Stimulation of the motor cortex with a single pulse elicited MEPs in none of the patients, while stimulation with a train-of-five rectangular pulses at high frequency elicited MEPs in all patients. The relationship between MEP amplitude and the level of neuromuscular block induced by vecuronium infusion was evaluated in seven patients. For comparison of the individual measurements, the MEP amplitude at a M-response amplitude of 100% was calculated by means of the individual regression curve as 100% of MEP amplitude. There was a linear correlation between percent MEP amplitude and percent M-response amplitude (r = 0.81; P < 0.01). Intraoperative monitoring of MEP could be performed at a M-response amplitude above 90 % of the baseline value in 10 patients and at a M-response amplitude of 20%-50% of the baseline value in 11 patients. During monitoring of the 21 patients, MEPs did not change in 18 patients and disappeared in two patients. In the remaining patient, MEP amplitudes were attenuated to approximately 10% of the baseline value and recovered after cessation of surgical manipulation. In the two patients in whom MEPs disappeared, motor paresis developed postoperatively. We conclude that 1) intraoperative myogenic MEP monitoring is feasible during isoflurane or sevoflurane anesthesia if stimulation is performed with a short train of rectangular pulses, and 2) that electromyographic monitoring of neuromuscular block is useful to assess intraoperative MEP changes under partial neuromuscular block.

Effect of niceritrol on fibrinolysis and lipoprotein (a) levels in patients with coronary artery disease

BACKGROUND

Lipoprotein (a) [Lp(a)] is an independent risk factor for coronary artery disease and niceritrol (a prodrug of nicotinic acid) is known to reduce Lp(a) levels. Patients with coronary artery disease often have impairment of the fibrinolytic system.

METHODS

To elucidate the effect of niceritrol on fibrinolysis and Lp(a) levels, we examined plasminogen activator inhibitor (PAI) activity, tissue-type plasminogen activator (t-PA) antigen, and serum Lp(a) levels before and after administration of niceritrol to coronary artery disease patients with high baseline Lp(a) levels (> or = 20 mg/dl). Niceritrol was administered to 26 patients for 12 weeks at 750 mg/day. Fasting blood samples were obtained at 0800 h from each patient before treatment, after administration of niceritrol for 12 weeks and 4 weeks after the discontinuation of therapy.

RESULTS

There were significant reductions in PAI activity (9.9 +/- 1.8 compared with 5.4 +/- 1.6 IU/ml, P < 0.01), t-PA antigen levels (10.0 +/- 0.5 compared with 8.8 +/- 0.6 ng/ml, P < 0.05), and Lp(a) levels (49.3 +/- 5.9 compared with 42.5 +/- 5.4 mg/dl, P < 0.01) after 12 weeks of niceritrol administration. Four weeks after the discontinuation of niceritrol treatment, all these parameters returned to baseline.

CONCLUSIONS

This study demonstrated that niceritrol administration decreases PAI activity and t-PA antigen levels together with Lp(a) levels in patients with coronary artery disease. These observations suggest that niceritrol administration may tend to normalize fibrinolysis in such patients.

Management of subarachnoid fluid collection in infants based on a long-term follow-up study

We report the natural history and management of subarachnoid fluid collections in infants and their management based on a longterm follow-up study in 20 cases. These subarachnoid fluid collections were resolved spontaneously in 17 of 20 patients and only 3 by surgical intervention at the age of 2. In our 20 patients the natural history of subarachnoid fluid collection in infants was benign unless the patients sustained head trauma. Surgical treatment was performed in the cases where a subarachnoid fluid collection developed into a subdural haematoma. Head trauma may precipitate subdural haematoma in patients with subarachnoid fluid collection. All patients except one who underwent the placement of subdural-peritoneal shunt, attained normal psychomotor development in time. During the follow-up period of 3 to 10 years after resolution of the fluid collection, no patient has had a recurrence once it resolved.

[Otoacoustic emissions of full-term and preterm neonates]

Transiently evoked otoacoustic emission (TEOAE), distortion product otoacoustic emission (DPOAE), and spontaneous otoacoustic emission (SOAE) were measured in 45 full-term neonates (68 ears) and 12 preterm neonates (20 ears) with ILO88 & 92. Measurements were performed in the nursery of the obstetrics ward or NICU (not sound proof room) under natural sleeping condition after nursing. No sedating agent was used. TEOAEs were rated "good response" in 61 (89.7%) of 68 full-term neonate ears. DPOAEs were rated "good response" in 40 (71.4%) of 56 full-term neonate ears. SOAEs were detectable in 25 (62.5%) of 40 full-term neonate ears. Considering the high positive rate of TEOAE in full-term neonates and the easy and noninvasive method of measurement, we concluded that TEOAE is useful for auditory screening in neonates. There was failure to detect TEOAEs in 7 ears and the measurements were all performed within 6 days after birth. Some reports claim that residual amnion in the external auditory canal or the middle ear in the first few days after birth causes slight hearing loss. Thus, we expected that making the measurements more than 7 days after birth might yield higher "good response" rates. We sometimes found that the Total Echo Powers of TEOAEs were reduced by the poor condition of the ear probe. Thus, we must be very careful in regard to this technical problem in order to perform accurate examinations. Because of its lower "good response" rate, DPOAE was not as useful for screening as TEOAE. Because of the movements or respiratory noises of the newborn infants, it was hard to detect reliable DPOAEs, particularly in the low frequency range. On the other hand, because of its frequency specificity, particurally at high frequencies, DPOAE will be useful for detecting the partial hearing impairment such as congenital high-tone hearing impairment. It would be difficult to use SOAE as a clinical test. Because it is not an evoked response, its mechanism of generation is not well understood. We expect that following longitudinal changes in SOAE in neonates may yield some information about it. We measured mainly TEOAE in preterm neonates because we had to complete the measurements as soon as possible. High Total Echo Powers of TEOAEs were recorded in most infants over 38 weeks of PCA (post conceptional age). The earliest case showed reliable TEOAE at 35 weeks PCA. In most cases that could be measured twice on different days, the Total Echo Powers of TEOAE, were higher in the second time. We therefore concluded that TEOAE might serve as an examination for monitoring the maturation of preterm neonate hearing.

Logistic character of myocardial twitch force curve: simulation

We found that the isovolumic pressure-time curve of the canine left ventricle closely fitted the difference of two logistic function curves and that the isovolumic relaxation-pressure curve segment was more reliably characterized by a logistic time constant than by the conventional exponential time constant. We therefore hypothesized that the calcium (Ca) transient and the Ca-troponin (Tn) binding and crossbridge (CB) kinetics underlay the logistic character of the ventricular isovolumic pressure curve. We tested this hypothesis with a computer simulation of a simple Ca and CB kinetics model of myocardial isometric twitch force development. We assumed the instantaneous number of attached CBs that was theoretically given as the difference between the cumulative CB attachment and detachment curves. We radically changed the Ca transient, Ca-Tn binding, and CB kinetic parameters. We always found that both the cumulative CB attachment and detachment curves closely fitted logistic functions. The difference curve of these two best-fit logistic functions closely fitted the theoretical F curve with certain combinations of the Ca transient, the Ca-Tn binding, and the CB kinetic parameters. These results seem to support our hypothesis.