Chronic lead exposure may inhibit endothelium-dependent hyperpolarizing factor in rats

We designed experiments to determine the effect of chronic lead exposure on endothelium-dependent responses to acetylcholine (Ach) in rat isolated blood vessels. Male Wistar rats were maintained for 1 or 3 months with or without oral lead administration. Membrane potential and isometric tension were measured in mesenteric arteries. Ach caused concentration- and endothelium-dependent relaxation in rings with endothelium contracted with phenylephrine (PE). There was no significant difference in relaxation between lead-exposed and control animals. In the presence of NG-nitro-L-arginine methyl ester (L-NAME), both endothelium-dependent hyperpolarization and relaxation to Ach were significantly reduced in animals from the 3-month lead-exposed group. In aorta from lead-exposed groups, endothelium-dependent relaxation to Ach was not significantly different from that of age-matched controls, whereas both were completely inhibited in the presence of L-NAME. The basal levels of cyclic GMP in the aorta were not affected by lead exposure regardless of duration. These data indicate that both endothelium-dependent hyperpolarization and L-NAME-resistant relaxation decrease with chronic lead exposure in rat mesenteric arteries and suggest that lead is an inhibitor or endothelium-derived hyperpolarizing factor (EDHF).

The effect of ovariectomy on the temporomandibular joints of growing rats

PURPOSE

This investigation studied the effects of ovariectomy, on the temporomandibular joints (TMJ) of young rats.

MATERIALS AND METHODS

Four-week-old female Wistar rats were ovariectomized and killed at the intervals of 1, 2, 4, and 8 weeks postoperatively. Histomorphometric study of the TMJ was performed in a synchronous manner with an age-matched sham-operated control group. The serum levels of estrogen, calcitonin, and C-terminus parathyroid hormone were also determined.

RESULTS

In the sham-operated control group, the serum levels of estrogen and calcitonin increased with age. An increase of the bone volume, with a concomitant increase of the osteoid surface, was observed at 12 weeks. Thickness of the articular soft tissue was decreased with increasing age. In the ovariectomized animals, serum estrogen was not detected during the experiment. A biphasic change in the parathyroid hormone level, with decreases at 1 and 2 weeks after the ovariectomy and increases at 4 and 8 weeks postoperatively, was observed, whereas a constant value was noted in the calcitonin level. Thickness of the articular soft tissue was increased in the anterior and central portions of the condyle at 1, 2, and 4 weeks after the ovariectomy, whereas no appreciable changes were observed in the posterior portion. The bone volume was decreased during the experiment, particularly in the posterior portion. An osteophyte in the anterior region was also observed 8 weeks postoperatively.

CONCLUSIONS

Estrogen deficiency in rats during puberty predisposes to alterations of the TMJ through changes in serum calcitonin and parathyroid hormone levels.

Serial magnetic resonance images in a patient with congenital sensory neuropathy with anhidrosis and complications resembling heat stroke

We report the results of serial computerized tomography (CT) and magnetic resonance imaging (MRI) in a 9-month-old Japanese girl with the rare disorder, congenital sensory neuropathy with anhidrosis (CSNA). She developed a prolonged high fever, anorexia, and weight loss with laboratory findings of hemoconcentration and elevated levels of GOT, LDH and creatine phosphokinase (CK) in May 1995, and was hospitalized. The cerebrospinal fluid (CSF) was normal on admission. Elevation of CSF myelin basic protein on the 16th hospital day suggested a destruction of the myelin sheath. The first MRI performed on the 16th hospital day revealed no marked abnormalities when the patient exhibited a high fever, generalized tonic-clonic convulsions, and impaired consciousness. The patient had a persistent high fever, and developed a second generalized tonic clonic convulsion and became comatose. A second MRI on the 20th hospital day showed a bilateral symmetrical paracentral hypo-intensity of the white matter with occipital hypo-intensity on T2-weighted images. MRI findings were considered to represent the complications of the high fever with a loss of water from the cerebral cortices and deep white matter. MRI and CSF findings indicated the presence of brain damage due to the high fever.

[Influence of multiple-dose administration of cefetamet pivoxil on blood and urinary concentrations of carnitine and effects of simultaneous administration of carnitine with cefetamet pivoxil]

Cefetamet pivoxil (CEMT-PI), a drug of pivaloyloxymethyl group, was investigated for its impact on the carnitine blood homeostasis and renal excretion upon administering CEMT-PI alone, and CEMT-PI simultaneously with carnitine. 500 mg of CEMT-PI (group A) and 500 mg of CEMT-PI and an equimolar amount (200 mg of carnitine) of levocarnitine chloride (group B) were administered twice a day for 7 and 1/2 consecutive days to 5 healthy volunteers (group A) and 3 healthy volunteers (group B). No serious side effects nor abnormal values in physical and laboratory tests were observed throughout the study in both groups. During the treatment period, plasma total carnitine decreased slowly down to 25.5 microM (group A) and 38.8 microM (group B) and plasma free carnitine reached steady state levels at 17.7 microM (group A) and 29.2 microM (group B) on day 5. These concentrations represent 45 and 37% in group A, 66 and 58% in group B of the average pre-treatment baseline levels. Plasma pivaloylcarnitine quickly reached plateau levels of 6.12 microM (group A) and 4.05 microM (group B) on day 4. After treatment stop, plasma total and free carnitine returned to the pretreatment baseline level within 5 days (group A) and 3 days (group B), and plasma pivaloylcarnitine was detectable until day 7 of the treatment-free follow up in both groups. Although carnitine was given concurrently at a dose equimolar to the ingested amount of pivalic acid in group B, the plasma total and free carnitine exhibited a decrease. This was considered attributable to the fact that the bioavailability of carnitine is as low as 16% when administered orally, which is considerably less compared to the 55% bioavailability of cefetamet pivoxil.

Optical Fourier processing using photoinduced dichroism in a bacteriorhodopsin film

The photoinduced dichroism in bacteriorhodopsin films has been investigated in view of its application for optical Fourier processing. A simple optical system for Fourier processing is demonstrated that does not require precise alignment and vibration isolation. The basic principle of operation relies on the intensity dependence of photoinduced dichroism in a bacteriorhodopsin film. Experimental results with Fourier processing are shown for edge enhancement.

Intrathyroidal T cell accumulation in Graves' disease: delineation of mechanisms based on in situ T cell receptor analysis

We have explored the pattern of T cell clonal and nonclonal expansion within the thyroid glands of 7 patients with surgically treated hyperthyroid Graves' disease. Radiolabeled RT-PCRs were performed with 18 V alpha and 21 V beta oligonucleotides as forward primers and 32 P-labeled constant (C) region oligonucleotides as reverse primers, giving 273 experiments in all. Peripheral blood mononuclear cells showed CDR3 banding patterns involving at least 6-12 distinct bands per V gene family. However, 2 distinct banding patterns were seen with intrathyroidal T cell samples. The first was a limited number of bands (< 6), representing within V gene family restriction, seen in 38/153 (25%) PCR positive samples. The second was the presence of markedly enhanced bands representing either clonal expansion or accumulation of T cells using the same V gene with the same CDR3 length and observed in 15/153 (10%) of samples. Further examination of the enhanced bands by sequencing of gel-selected PCR-amplified V gene products showed the presence of both T cell clonal expansion, as evidenced by similar CDR3 sequences, and in a few samples, heterogenous T cell populations, as evidenced by differing CDR3 sequences, yet all sharing the same V gene family. These data support the hypothesis that the human intrathyroidal T cell population in Graves' disease was selected by two distinct mechanisms. The first was associated with the TcR V gene invariant product and represented by nonclonal accumulation of T cells sharing the same V gene. The second mechanism responsible for T cell accumulation was specific antigen recognition by the human T cell receptor CDR3 region and was represented by clonally expanding T cells.

Inhibitory effect of MS-153 on elevated brain glutamate level induced by rat middle cerebral artery occlusion

BACKGROUND AND PURPOSE

In this study we investigated the effects of a novel compound, MS-153 ([R]-[-]-5-methyl-1-nicotinoyl-2-pyrazoline), on elevated brain glutamate concentrations and cerebral infarct volume induced by middle cerebral artery (MCA) occlusion in the rat.

METHODS

The rat MCA was occluded by a thrombus induced by a photochemical reaction between green light and the photosensitizer dye rose bengal, which causes endothelial injury followed by formation of a platelet- and fibrin-rich thrombus at the site of photochemical reaction; this method is routinely used in our laboratory to produce arterial occlusion in experimental animals. Extracellular glutamate concentration at the ischemic border zone was determined by a microdialysis technique. The size of cerebral infarction was measured by a histochemical technique 24 hours after MCA occlusion. MS-153 was administered at various doses as a continuous infusion for 24 hours, beginning 0 to 2 hours after MCA occlusion.

RESULTS

At the ischemic border zone, the concentration of glutamate in the extracellular fluid increased by 40-fold after ischemia. At 3.13 mg/kg per hour, MS-153 reduced glutamate concentration (P < .05) and also the size of ischemic cerebral infarction (P < .05). Furthermore, the glutamate uptake inhibitor DL-threo-beta-hydroxyaspartate reversed the effect of MS-153 on glutamate concentration.

CONCLUSIONS

The reduction in the size of cerebral infarction by MS-153 may be attributable to the inhibition of glutamate release or an increase in cellular glutamate uptake.

Altered prostaglandin metabolism induced by angiotensin-converting enzyme inhibitors in broncho-alveolar lavage fluid of the guinea pig

The aim of this study was to investigate if prostaglandin (PG) metabolism is altered by angiotensin-converting enzyme (ACE) inhibitors as determined in the broncho-alveolar lavage fluid (BALF) of the guinea pig. Enalapril or imidapril was orally administered once a day for 2 weeks to Hartley male guinea pigs. Twenty-four hours after the last treatment, BALF was collected and the concentrations of PGI2, thromboxane A2 (TXA2) and PGE2 were measured by enzyme immunoassay. Enalapril significanlty P < 0.05) increased the TXA2 content, which was inhibited by indomethacin treatment and significantly (P < 0.05) decreased the PGI2 content. Imidapril, however, did not affect TXA2 or PGI2 generation. These findings suggest that altered PG metabolism may be associated with coughing as a side effect of enalapril.

Expression of parathyroid hormone (PTH)-related peptide (PTHrP) and PTH/PTHrP receptor in giant cell tumour of tendon sheath

The giant cell tumour of tendon sheath (GCTTS) is mainly composed of mononucleated stromal cells (SC) and multinucleated giant cells (GC), so-called osteoclast-like GC. It is thought that GC are derived from SC, but their precise relationship is not fully understood. Parathyroid hormone (PTH)-related peptide (PTHrP) is now considered to be a cytokine for cell differentiation, which may stimulate osteoclast-like cell formation in haematopoietic cells. Five cases of GCTTS were evaluated immunohistochemically, using a variety of antibodies against PTHrP, PTH/PTHrP receptor, KP-1 as a histiocytic phenotypic antigen, fibronectin as a fibroblastic phenotypic antigen, and proliferating cell nuclear antigen (PCNA). In situ hybridization and immunohistochemistry revealed that in all cases both SC and GC expressed PTHrP. PTH/PTHrP receptor was observed only in histiocytic SC and GC, but not in fibroblastic SC. Almost all GC showed histiocytic features. PCNA immunoreactivity was detected only in the nuclei of SC, and not in GC. Moreover, SC with PTH/PTHrP receptor immunoreactivity were negative for PCNA. These results suggest that GC are derived from histiocytic SC expressing PTH/PTHrP receptor and losing proliferative activity in the process of transition from mononuclear to multinucleated. PTHrP produced by SC and GC may be involved in the formation of osteoclast-like cells in GCTTS by acting in an autocrine/paracrine fashion.

The role of T cells expressing TcR V beta 13 in autoimmune thyroiditis induced by transfer of mouse thyroglobulin-activated lymphocytes: identification of two common CDR3 motifs

The transfer of lymphocytes from mouse thyroglobulin (mTg)-immunized CBA/J (H-2k) mice following in vitro activation with mTg initiates experimental autoimmune thyroiditis (EAT) in syngeneic recipients. We have analyzed the T cell receptor (TcR) V gene families used by the intrathyroidal lymphocytic infiltrate of such mice. Using a radiolabeled RT-PCR technique with oligonucleotides detecting 17 mouse TcR V beta gene families to examine the heterogeneity of the amplified V-D-J (CDR3) fragments, we demonstrated that only the TcR V beta 13 amplifications consistently showed two similar homogeneous CDR3 sizes consistent with two clonally expanded T cell populations. Sequencing of the homogeneous RT-PCR products from these V beta 13++ populations confirmed the presence of clonal expanded T cells and identified two recurrent CDR3 motifs LTGKDTQ and LGEQ present in six of the seven samples. Both these motifs had been found as contributors to the T cell population in our previous studies of CBA/J mouse thyroiditis induced by active immunization with heterologous human (h) Tg. These data suggest that the autoepitope recognized was shared between hTg and mTg. It appears, therefore, that in transfer thyroiditis the intrathyroidal T cell clonal proliferation follows the homing of V beta 13 antigen-specific T cells which have been expanded by a brief (3 day) in vitro activation to mTg and utilize two distinct CDR3 motifs. CDR3 size heterogeneity in many of the other expressed V gene families also suggested the accumulation and recruitment of selected bystander T cells responding to additional but limited Tg or other self epitopes, perhaps on the basis of CDR3 shape rather than sequence. Such T cells may also have integral roles in the development of autoimmune thyroiditis.

A simple procedure for large-scale purification of 9-cis beta-carotene from Dunaliella bardawil

For experiments designed to obtain reliable data on the metabolic pathway and biological function of 9-cis beta-carotene, sufficient quantity of this substance in pure form is needed. For this purpose, we decided to purify 9-cis beta-carotene from the dry powder of the alga Dunaliella bardawil. By use of both silica gel and ODS open column chromatography and high-performance liquid chromatography (HPLC) on an ODS column and by treatment of the sample with ethanol, we could obtain this carotenoid as fine needle-shaped orange crystals. They were found to be highly pure as judged by analytical HPLC, absorption spectrum, and nuclear magnetic resonance analysis.

A comparative study of the antithrombotic effect of aurintricarboxylic acid on arterial thrombosis in rats and guinea pigs

1. The antithrombotic effect of aurintricarboxylic acid (ATA) which inhibits binding of von Willebrand factor (vWF) to platelet glycoprotein lb (GPlb) receptor was evaluated in photochemically-induced thrombosis models in the femoral artery of rats and guinea-pigs. 2. ATA at a dose of 10 mg kg-1 significantly prolonged the time required for thrombotic occlusion of the artery in rats. The antithrombotic efficacy was associated with a significant inhibition of platelet retention and ex vivo botrocetin-induced platelet aggregation. 3. On the other hand, in guinea-pigs, ATA at the same dose inhibited the platelet retention and the platelet aggregation, but did not prevent thromboocclusion. 4. ATA inhibited aggregation of washed platelets from rats or guinea-pigs in response to botrocetin and thrombin in a dose-dependent manner (1-30 microM), and to the same extent. 5. ATA moderately increased activated partial thromboplastin time and bleeding time in both species. 6. These results indicate that vWF may play a role in the development of occlusive arterial thrombosis in the rat, but not in the guinea-pig. 7. The antithrombotic activity of ATA may partly arise from its inhibitory effect on thrombin, in addition to that on the vWF-GPlb pathway

In vivo microdialysis to determine the relative pharmacokinetics of drugs

The purpose of this study was to evaluate a simultaneous microdialysis method in blood and brain striatum to determine the relative pharmacokinetics and metabolism of L-3,4-dihydroxypenylalanine (L-dopa). L-Dopa (250 mumol/kg) was administered to rats with or without the aromatic amino acid decarboxylase (AADC) inhibitor carbidopa (25 mumol/kg) or benserazide (25 or 62.5 mumol/kg). L-Dopa, its metabolites, and AADC inhibitors in dialysates were analyzed by high performance liquid chromatography with an electrochemical detector. A moment analysis was also made to obtain pharmacokinetic parameters. After administration of L-dopa alone, it and its related metabolites were detected in both dialysates of blood and brain striatum. Coadministration of carbidopa (25 mumol/kg) or benserazide (62.5 mumol/kg) significantly enhanced the striatal amount of L-dopa by 8.0 and 6.1 times, respectively. Carbidopa and benserazide also increased striatal amounts of L-dopa metabolites, such as 3,4-dihydroxyphenylacetic acid, homovanillic acid, and 3-methoxy-4-hydroxyphenylethyleneglycol. Inhibition effect of benserazide on an extracerebral decarboxylation of L-dopa to dopamine (DA) was stronger than that of carbidopa. Carbidopa showed a higher striatal level of DA than benserazide. These results suggest a different effect of the two inhibitors on the DA formations in blood and brain striatum, and on the L-dopa transport through the blood-brain barrier (BBB). Thus, microdialysis is an easy and available method for simultaneously assessing the in vivo relative pharmacokinetics and metabolism of drugs in systemic circulation and a target organ.

Reversibility of compound action potential during the acute phase after transitory local ischemia

We investigated the reversibility of compound action potential (CAP) changes induced after transitory local ischemia induced by rose bengal photochemically induced thrombosis of the rat anterior inferior cerebellar artery (AICA). Cochlear blood flow (CBF) was measured with a laser-Doppler flowmeter positioned on the lateral bony wall of the basal turn of the cochlea, and the CAP to an 8-kHz half-wave of sinusoid sound at 100 dB sound pressure level was monitored. The irradiation was started 5 minutes before the rose bengal administration and continued through the thrombosis formation. Tissue-type plasminogen activator (t-PA, 1 mg/kg) dissolved in saline was injected intravenously 2 minutes after complete photothrombotic blockade of the AICA in the rats presenting complete abolition of CAPs just after the vascular occlusions. Nineteen of the 51 rats presented complete abolition of the CAP just after the AICA occlusion, and the thrombosed AICA was successfully reperfused by t-PA administration in 11 of the 19 rats. The result showed that duration of ischemia was the more important determinant for the reversibility of CAPs during the acute phase (p = .00001), and the residual level of cochlear blood flow during ischemia was also an important factor (p = .066). It appeared that the critical time of ischemia for the complete recovery of CAPs was around 5 minutes, and that the critical limit for the irreversibility of CAPs within the acute phase was between 20 and 25 minutes.

Increase in shedding of intercellular adhesion molecule-1 in human malignant melanoma cell lines treated with hyperthermia in vitro

Human malignant melanoma cell lines were found to increase shedding of soluble intercellular adhesion molecule-1 (sICAM-1) into the culture medium when the cells were treated with hyperthermia at 41-43 degrees C for 3-6 hr in vitro. The content of ICAM-1 in the cell lysate was also found to be increased after hyperthermia. The increased rate of ICAM-1 concentration in the cells was at maximum when they were incubated at 41 degrees C for 3 hr. Also, the melanoma cell lines heat-treated at 41 degrees C showed more intense immunofluorescence in the ICAM-1 expression on the cell surface. It remains to be investigated further whether the effects of hyperthermia on the ICAM-1 expression in melanoma cells is to augment membrane ICAM-1 expression, which in turn leads to shedding of soluble ICAM-1 or only to acceleration of shedding of sICAM-1 by unknown mechanisms.

The measurement of caffeine concentration in scalp hair as an indicator of liver function

Caffeine concentration in plasma and scalp hair has been determined for subjects consuming normal daily amounts of caffeine and the results used as an indicator of individual hepatic metabolic capacity. Daily exposure to caffeine was assessed in six healthy Japanese volunteers by direct HPLC measurement of the concentrations of caffeine in aliquots of all caffeine-containing beverages consumed by the subjects. The measurements were repeated on three different occasions for each subject and caffeine consumption (mean +/- s.d.) was calculated as 178.0 +/- 84.3 mg day-1 with an intra-individual variability of 23.8 +/- 6.3% as coefficient of variation. A survey of daily caffeine consumption in 121 adult Japanese by means of a questionnaire revealed a similar value (231.8 +/- 177.8 mg day-1). Caffeine concentration in the plasma sampled during an overnight caffeine-free interval was measured by HPLC and a comparison made between healthy subjects and patients with liver disease (0.71 +/- 0.32, 0.77 +/- 0.45 and 3.92 +/- 1.91 micrograms mL-1 for healthy volunteers (n = 6), patients with hepatitis (n = 11) and those with liver cirrhosis (n = 4), respectively). Strands of scalp hair were collected from six healthy subjects and six patients with liver cirrhosis. Caffeine in hair was identified and measured by gas chromatography-mass spectrometry after digestion of the hair matrix with protease and extraction of the caffeine with chloroform. Caffeine concentration in hair collected from patients with liver cirrhosis (26.5 +/- 5.04 ng mg-1 hair) was significantly higher than that in hair sampled from healthy subjects (7.21 +/- 3.11 ng mg-1). These findings suggest that the determination of caffeine concentration in the plasma and hair of subjects consuming normal daily amounts of caffeine-containing beverages provides a practical assessment of individual liver metabolic capacity.

Comparative electrophysiological effects of the antidepressants fluvoxamine and amitriptyline in the canine heart after myocardial infarction

We studied the effects of fluvoxamine and amitriptyline on epicardial activation delay of premature excitations, the effective refractory period, and the incidence of ventricular arrhythmias by programmed electrical ventricular stimulation in the canine heart after myocardial infarction. Additionally, we investigated whether the inhibition of norepinephrine reuptake by amitriptyline contributes to epicardial activation delay or arrhythmias by combination with propranolol pretreatment. Amitriptyline, at a dose of 3 mg/kg, significantly prolonged epicardial activation delay of premature excitations in the infarcted zone in a frequency-dependent manner (n = 10). Amitriptyline also prolonged epicardial activation delay of premature excitations in the normal zone (n = 10). The effective refractory period in the infarcted zone was significantly prolonged by amitriptyline at a dose of 3 mg/kg (n = 8). Amitriptyline increased the incidence of ventricular arrhythmias induced by programmed electrical ventricular stimulation (n = 8). Propranolol did not affect the epicardial activation delay caused by amitriptyline or the incidence of ventricular arrhythmias induced by programmed electrical ventricular stimulation (n = 6). Fluvoxamine, on the other hand, had no significant effect on epicardial activation delay of premature excitations (n = 10) or the effective refractory period (n = 8) in both the infarcted and normal zones. Fluvoxamine did not increase the incidence of ventricular arrhythmias induced by programmed electrical ventricular stimulation (n = 8).

A novel tumor-associated antigen expressed in human uterine and ovarian carcinomas

BACKGROUND

A large number of monoclonal antibodies (MoAbs) against human tumor cells have been generated and it has been shown that these MoAbs are useful tools in the diagnosis and treatment of cancer patients, as well as in the basic investigation of the oncogenesis and characterization of cancer cells.

METHODS

The 22-1-1 MoAb was established by cell fusion between mouse myeloma cells and spleen cells derived from mice immunized with the human uterine cervical adenocarcinoma cell line, SiSo. The tissue distribution and biologic characteristics of the 22-1-1 antigen (Ag) were examined.

RESULTS

The 22-1-1 Ag was distinct from the known tumor-associated antigens such as YH 206, GA 733, CA 125, carcinoembryonic antigen, and sialyl Le(x) molecules in an expression pattern in human tumor cell lines. An immunohistochemical study revealed that 22-1-1 Ag was expressed in 87.5% of uterine cervical adenocarcinomas, 66% of uterine endometrial adenocarcinomas, and 58.8% of ovarian carcinomas. Moreover, 22-1-1 Ag was detected in 87.7% of uterine cervical squamous cell carcinomas; however, it was not detected in 87.7% of uterine cervical or ovarian tissues, except in uterine endometrial glands, in which its expression was observed at low levels. The 22-1-1 Ag was secreted into cell culture supernatant fluids and was also detected in the vaginal discharges of uterine cervical carcinoma patients. The antigenic epitope of 22-1-1 Ag was shown to be a protein with a molecular weight of 78 kilodaltons using sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis.

CONCLUSIONS

The 22-1-1 MoAb reactive to a novel tumor-associated antigen was generated. This Ag was expressed in cancer cells derived mainly from the uterus and ovary. Moreover, 22-1-1 Ag was associated in the vaginal discharges of uterine cervical carcinoma patients. 22-1-1 MoAb is a potential tool for the study of oncogenesis and the management of cancer patients.

Information theoretic analysis of action potential trains. II. Analysis of correlation among n neurons to deduce connection structure

We propose a cross-correlational method based on information theory, which produces a network connection structure to account for observed patterns of action potential activity in multi-unit recordings. Firing probabilities and conditional probabilities are estimated from the action potential trains of n neurons. Two-point mutual information (2pMI) and joint conditional mutual information (JCMI) are calculated by using the estimated probabilities, and then the n-point mutual information (npMI) is calculated. A significant peak of npMI indicates that each neuron is connected to all other neurons at specified time differences, either directly or indirectly. To distinguish between direct and indirect connection, the two-point m-joint conditional mutual information (2pJCMI) is calculated over the peak region for each pair of neurons. A minimum effective connection structure among the n neurons can be deduced in this manner. The procedure for deducing the connection structure for three- and n-neuron networks is described. We apply this method to action potential trains produced by simulated neural networks. Some limitations of the method are also discussed.

Pharmacokinetics and safety of a novel, long-acting, prodrug-type potassium channel opener, Y-27152, in healthy volunteers

The pharmacokinetics and safety of a novel, long-acting, prodrug-type K(+)-channel opener, Y-27152, were investigated in healthy male volunteers. In the first phase, single oral doses of 0.1, 0.25, 0.5, 0.75, and 1.0 mg of Y-27152 (n = 3-6 per dose) were given after overnight fasts in a dose-escalating manner. The 0.75-mg dose was given both after an overnight fast or after food to examine the effects of food intake. In the second phase, multiple doses of Y-27152 were taken after meals once daily for 7 consecutive days. In part A of this phase, either placebo (n = 3) or 0.5 mg of Y-27152 (n = 6) was taken for 7 days, and in part B of this phase 0.5-, 0.75-, and 1.0-mg doses were taken in a dose-escalating manner for 1,3, and 3 days, respectively (n = 9). In the single-dose study, peak concentration (Cmax) and area under the plasma concentration-time curve (AUC) of main active metabolite (Y-26763; M1) increased in parallel with dosage. This dose-linearity was less obvious with Y-27152, which had an AUC approximately 6 to 10 times less than that of M1. Administration with food at 0.75 mg resulted in a small but significant decrease (approximately 10%) in the Cmax and AUC of M1. At doses of 0.5 mg or higher, participants experienced headaches and palpitations, which were probably due to the vasodilatory effects and did not require treatment. Mean diastolic blood pressure significantly decreased and pulse rate increased at doses of 0.5 mg or higher compared with predose values. Plasma renin activity was significantly elevated 4 hours after the administration of the 0.75- and 1.0-mg doses, but showed no significant change at 0.5 mg. In the multiple-dose study, the time profile of the plasma concentration of M1 approximately coincided with the simulation curves worked out using the pharmacokinetic parameters obtained in the singledose study. The incidence of headaches tended to increase with dose in part B, but drug administration was not discontinued in any case. Plasma renin activity again increased 4 hours after administration. In phase B of the multiple-dose study, diastolic blood pressure decreased and pulse rate increased compared with predose values. Y-27152 was metabolized to M1 and well tolerated in healthy volunteers, and its pharmacologic effects were likely caused by vasodilation, which could make it an effective antihypertensive agent.

A chemiluminescent detection of superoxide radical produced by adherent leucocytes to the subendothelium following thrombolysis: studies with a photochemically induced thrombosis model in the guinea pig femoral artery

Reocclusion following thrombolysis is a major limitation of thrombolytic therapy with recombinant tissue-type plasminogen activator (rt-PA) because denuded vessel wall exposed to blood following thrombolysis is a favourable surface for platelet and leucocyte deposition. We have applied a chemiluminescence technique to detect superoxide radical (0(-2)) produced by leucocytes adherent to the femoral artery 24 h after photochemically induced thrombogenesis in the guinea pig in vivo and subsequent thrombolysis by rt-PA. Intravenous administration of MCLA, a specific chemiluminescence reagent for detecting O(-2), markedly increased photon emission. the photon emission was markedly potentiated by phorbol myristate acetate and was suppressed by superoxide dismutase. Reocclusion 24 h after rt-PA induced thrombolysis was observed in 10 of 16 animals. Histological observations revealed extensive polymorphonuclear leucocytes adherent to the vessel wall at the site of thrombogenesis and thrombolysis. A higher level of 0(-2) could be detected from the arteries in which thrombolysis was induced compared with those without thrombolysis. Further, the level 0(-2) detected was greater in reoccluded arteries compared with those in which reflow was established. These observations suggest that 0(-2) is produced by adherent leucocytes at the site of thrombolysis and that leucocytes are involved in reocclusion after thrombolysis.

Multicenter evaluation of a colorimetric microplate antimycobacterial susceptibility test: comparative study with the NCCLS M24-P

A colorimetric test method using the microplate culture technique for the determination of susceptibility of Mycobacterium tuberculosis against antimycobacterial agents was developed and evaluated by the multicenter study. The test method utilizes an oxidation-reduction dye, 2,3-diphenyl-5-thienyl-(2)-tetrazolium chloride (STC), as an indicator of mycobacterial growth. When compared to the presently available test method, some modifications were also included; lower inoculum density (10-fold dilution), inclusion of an inoculum diluted 1:100 as a growth control, and the preparation of inoculum preincubated in Middlebrook 7H9 broth and spectrophotometrically adjusted to McFarland #1 turbidity. The test method evaluated was highly precise and reliable to detect antimycobacterial resistances when the ATCC reference strains were tested. Also, the interpretations of the test result were highly comparable to those determined by the method of NCCLS M24-P, the % agreements ranging from 76.1% (ethambutol) to 91.3% (streptomycin). The test results were also comparable to those determined by Ogawa media; > 90% agreed with susceptible, intermediate, or resistant. The appearance of mycobacterial colonies on the test media was easily read, and the test results were more comparable to those of NCCLS M24-P. With these results, it can be concluded that the colorimetric microplate susceptibility test method described will be more suitable for clinical mycobacteriology laboratories.

Measurement of 5-fluorouracil in scalp hair: a possible index of patient compliance with oral adjuvant chemotherapy

OBJECTIVE

Little is known about patient compliance with oral adjuvant chemotherapy. It is estimated to be poor especially in Japan, where it is still unusual for patients to be directly informed of their diagnosis of malignancy. 5-Fluorouracil (5-FU) was measured in hair samples to assess patient exposure to 5-FU, and its potential usefulness is discussed as an index of compliance with postoperative adjuvant chemotherapy.

METHODS

Hair samples obtained from 55 patients, who had received oral 5-FU (total dose 27-41 g) as postoperative adjuvant chemotherapy over a 6-month period, were used for the analysis of 5-FU. The drug was extracted from the hair using ethyl acetate, and its fluorescence derivatization was employed for measurement with HPLC. The detection limit of 5-FU in hair was 0.01 ppm.

RESULTS

In 22 out of 55 samples 5-FU content was under the detection limit, whereas in the remaining 33 samples the drug was detected in a range of 0.006-2.125 ng per hair strand; in addition, drug content showed a lognormal distribution. 5-FU was detected in the hair collected from those patients who were possibly compliant with the postoperative oral adjuvant chemotherapy.

CONCLUSION

As many as 40% of the patients analysed were supposed to be much less compliant. Even in the possibly compliant patients, the degree of compliance with the therapy varied according to a log-normal distribution.

A novel tumor-associated antigen expressed in human uterine and ovarian carcinomas

BACKGROUND

A large number of monoclonal antibodies (MoAbs) against human tumor cells have been generated and it has been shown that these MoAbs are useful tools in the diagnosis and treatment of cancer patients, as well as in the basic investigation of the oncogenesis and characterization of cancer cells.

METHODS

The 22-1-1 MoAb was established by cell fusion between mouse myeloma cells and spleen cells derived from mice immunized with the human uterine cervical adenocarcinoma cell line, SiSo. The tissue distribution and biologic characteristics of the 22-1-1 antigen (Ag) were examined.

RESULTS

The 22-1-1 Ag was distinct from the known tumor-associated antigens such as YH 206, GA 733, CA 125, carcinoembryonic antigen, and sialyl Le(x) molecules in an expression pattern in human tumor cell lines. An immunohistochemical study revealed that 22-1-1 Ag was expressed in 87.5% of uterine cervical adenocarcinomas, 66% of uterine endometrial adenocarcinomas, and 58.8% of ovarian carcinomas. Moreover, 22-1-1 Ag was detected in 87.7% of uterine cervical squamous cell carcinomas; however, it was not detected in 87.7% of uterine cervical or ovarian tissues, except in uterine endometrial glands, in which its expression was observed at low levels. The 22-1-1 Ag was secreted into cell culture supernatant fluids and was also detected in the vaginal discharges of uterine cervical carcinoma patients. The antigenic epitope of 22-1-1 Ag was shown to be a protein with a molecular weight of 78 kilodaltons using sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis.

CONCLUSIONS

The 22-1-1 MoAb reactive to a novel tumor-associated antigen was generated. This Ag was expressed in cancer cells derived mainly from the uterus and ovary. Moreover, 22-1-1 Ag was associated in the vaginal discharges of uterine cervical carcinoma patients. 22-1-1 MoAb is a potential tool for the study of oncogenesis and the management of cancer patients.