Participation of endogenous galanin in the suppression of baroreceptor reflex response by locus coeruleus in the rat

We evaluated the potential participation of endogenous brain galanin (GAL) in the suppression of baroreceptor reflex (BRR) response by locus coeruleus (LC), using adult male Sprague-Dawley rats anesthetized with pentobarbital sodium (40 mg/kg, i.p., with 15 mg/kg/h i.v. infusion supplements). Our physiologic and pharmacologic results demonstrated that bilateral microinjection of GAL antiserum (1:20, 20 nl) into the nucleus tractus solitarii (NTS), the terminal site for baroreceptor afferent fibers, significantly attenuated the suppressive effect of LC on the BRR response. Pretreatment with the same amount of normal rabbit serum (1:20) or heat-inactivated GAL antiserum (1:20), on the other hand, was ineffective. Microinjection of GAL (100 pmol) into the bilateral NTS also appreciably depressed the BRR response. Histochemically, retrogradely labeled neurons were distributed in the LC following microinjection of fast blue into the NTS. Immunofluorescent staining further revealed that some of these fast blue labeled LC neurons also showed positive immunoreactivity to GAL. These results suggest that a direct galaninergic projection to the NTS may participate in the suppression of BRR response by the LC.

Spectral analysis of arterial pressure variability during induction of propofol anesthesia

We studied the effect of continuous infusion of propofol on spectral components in systemic arterial pressure (SAP) signals in 35 consenting patients undergoing abdominal surgery. Anesthesia was induced with intravenous bolus administration of propofol (2.0 mg/kg), followed by infusion at either 5 mg.kg-1.h-1 (Group 1, n = 18) or 10 mg.kg-1.h-1 (Group 2, n = 17). Tracheal intubation was facilitated by administration of vecuronium (0.1 mg/kg). The SAP signal was subjected to off-line spectral analysis to obtain changes in power of the very low frequency (VLF; 0.00-0.08 Hz), low frequency (LF; 0.08-0.15 Hz), high frequency (0.15-0.25 Hz); and very high frequency (VHF; 0.80-1.60 Hz) components. Venous blood for the measurement of plasma concentration of propofol was collected at 5 min before bolus injection of propofol; at 5, 10, and 15 min after infusion of propofol; and immediately after endotracheal intubation. Infusion of propofol significantly decreased the total power of SAP spectrum in both groups, especially the VLF, LF, and VHF components at all intervals except postintubation. Immediately after tracheal intubation, patients in Group 1 showed a significant increase in mean arterial pressure when compared with those in Group 2 (118 +/- 5 mm Hg vs 102 +/- 5 mm Hg, P < 0.05). Similar change was also seen in the VLF component (7.4 +/- 0.7 mm Hg2 vs 4.4 +/- 0.5 mm Hg2, P < 0.05). After tracheal intubation, patients in Group 1 showed 15.7-, 3.3-, and 4.4-fold increase in the VLF, LF, and VHF components, respectively. There were 14.1-, 2.8-, and 2.8-fold increases in the respective components of the SAP signal in Group 2. At all intervals, the spectral components of SAP, however, did not correlate well with the plasma concentration of propofol in either group. These results suggest that spectral analysis of SAP signals may provide an alternative for assessing autonomic activities, such as the sympathetic response, to tracheal intubation during propofol anesthesia.

Nitric oxide as a mediator of cocaine-induced penile erection in the rat

1. The effect of local application of cocaine to the corpus cavernosum on intracavernous pressure (ICP), an experimental index for penile erection, was examined in Sprague-Dawley rats anaesthetized with chloral hydrate. The potential involvement of dopamine, noradrenaline or nitric oxide as the chemical mediator in this process, and the pharmacological action of cocaine as a local anaesthetic in the induced increase in ICP, were also investigated. 2. Intracavernous (i.c.) administration of cocaine (40, 80 or 160 micrograms) to the corpus cavernosum resulted in a dose-related increase in both amplitude and duration of ICP. 3. The elevation of ICP induced by cocaine (160 micrograms, i.c.) was not significantly influenced by prior injection into the corpus cavernosum of either the D1 or D2 dopamine receptor antagonist, R-(+)-SCH 22390 (250 pmol) or (-)-sulpiride (250 pmol). 4. Similarly, penile erection promoted by cocaine (160 micrograms, i.c.) was not appreciably affected by i.c. pretreatment with the alpha 1-, alpha 2-, or beta-adrenoceptor antagonist, prazosin (50 pmol), yohimbine (50 pmol) or propranolol (5 nmol). 5. Whereas lignocaine (4 mumol, i.c.) depressed penile erection induced by papaverine (400 micrograms, i.c.), local application of cocaine (160 micrograms) into the corpus cavernosum still elicited significant elevation in ICP in the presence of lignocaine or papaverine. 6. The increase in ICP induced by cocaine (160 micrograms, i.c.) was attenuated dose-dependently by prior cavernosal administration of the NO synthase inhibitor, N omega-nitro-L -arginine methyl ester (L-NAME, 0.5, 1 or 5 pmol) or NG-monomethyl-L-arginine (L-NMMA, 2.5, 5 or 10 pmol). The blunting effect of L-NAME or L-NMMA was reversed by co-administration of the NO precursor, L-arginine (1 nmol, i.c.). 7. Pretreatment by local application into the corpus cavernosum of methylene blue (2.5 mumol), an inhibitor of cytosolic guanylyl cyclase, antagonized cocaine-induced penile erection. 8. Direct i.c. administration of a NO donor, nitroglycerin (10 or 20 nmol), mimicked the local action of cocaine by promoting a significant increase in ICP. 9. It is concluded that cocaine may induce penile erection by increasing ICP via a local action on the corpus cavernosum. This process did not appear to involve either dopamine or noradrenaline as the chemical mediator, nor the pharmacological action of cocaine as a local anaesthetic. On the other hand, it is likely that initiation and maintenance of penile erection elicited by cavernosal application of cocaine engaged an active participation of NO and subsequent activation of guanylyl cyclase in the corpus cavernosum.

Auto- and cross-spectral analysis of cardiovascular fluctuations during pentobarbital anesthesia in the rat

We applied auto- and cross-spectral analysis of systemic arterial pressure (SAP) and heart rate (HR) signals to quantify the effects of pentobarbital sodium on short-term cardiovascular fluctuations in adult, male Sprague-Dawley rats. Intravenous administration of pentobarbital, delivered as a bolus injection (5, 10, or 20 mg/kg) or continuous infusion (10, 20, or 40 mg.kg-1.h-1), elicited only mild hypotension and tachycardia. This was accompanied by a dose-related depression of the very low (0-0.25 Hz) and low (0.25-0.8 Hz)-frequency components of both SAP and HR signals and high (0.8-2.4 Hz)-frequency component of HR signals. Cross-spectral analysis of SAP and HR signals during intravenous infusion of pentobarbital revealed a maintained coherence in the high-frequency range, together with a gradual and dose-related decrease in magnitude of transfer function and baro-receptor reflex sensitivity. Stable plasma concentration and all hemodynamic parameters were observed during 120 min of infusion at 20 mg.kg-1.h-1. Under this dosing condition, autonomic blockade by phentolamine, propranolol, or atropine still evoked discernible but differential reductions in the SAP and HR spectral components. Our data suggest that continuous intravenous administration of pentobarbital at 20 mg.kg-1.h-1 offers maintained anesthesia while preserving the capacity of cardiovascular regulation.

Implications of urinary basic fibroblast growth factor excretion in patients with urothelial carcinoma

1. Angiogenesis occurs in response to wounding, and is of vital importance for tumour growth and metastasis. Basic fibroblast growth factor, a well-known angiogenic factor, has been suggested to be a urine marker for urothelial carcinoma. However, the relevance of its detection has not been evaluated in a large number of patients. 2. Immunoassay of basic fibroblast growth factor was performed on urine samples from different aetiologies of urothelial disorder. Expression of basic fibroblast growth factor in the corresponding tumour was correlated with the urine level. 3. The excretion of basic fibroblast growth factor (ng/g creatinine) was significantly elevated in both inflammatory and neoplastic urological diseases compared with normal individuals (P < 0.05), while it was normalized in tumour-free subjects (P < 0.01). Receiver operating characteristic plotting revealed a sensitivity of 40% for tumour diagnosis at the cut-off point of 3.29 ng/g creatinine. The sensitivity of the test in predicting tumour recurrence was only 14%. The basic fibroblast growth factor level in urine showed a positive association with increasing age of cancer patients (P = 0.02) and with tumour grading (P = 0.05). However, no important relationship was observed regarding tumour stage, size, number, shape or degree of local inflammatory reaction (P > 0.01). Pairwise analysis of the basic fibroblast growth factor level in urine and its expression in corresponding tumours did not reveal a conspicuous correlation (r = -0.097, P = 0.43). 4. Our results suggested that estimation of urinary basic fibroblast growth factor cannot be satisfactory as a tumour marker. The measurement may represent one of the tissue responses to injury or the host-tumour interactions. A longitudinal study is required to elucidate the role of basic fibroblast growth factor in order to select the appropriate treatment strategy for urothelial carcinoma.

A new pre-S containing recombinant hepatitis B vaccine and its effect on non-responders: a preliminary observation

Nine healthy subjects who had no detectable antibody response when initially vaccinated with hepatitis B vaccine (plasma derived and/or yeast derived) were revaccinated with three 20 micrograms doses of a new recombinant hepatitis B (HB) vaccine (SCI-B-VAC) derived from Chinese hamster ovary (CHO) cells and consisting of both the major S protein and the minor pre-S (S1 and S2) proteins of the viral coat. Seroconversion was successful in 78% of these non-responders after the second dose and just before the third vaccination. The geometric mean titres of the antiHBs were 587 iu/l one month after the course of vaccination. This study, though preliminary, indicated that pre-S containing CHO vaccine is effective in inducing antibody response in S-vaccine non-responders and also suggested that the added pre-S region in HBV vaccine helps antiHBs production. Frequency of HLA B46 and B15 were higher in non-responders compared to normal subjects (P = 0.04) supporting the possibility that genetic factors may modulate the immune response to HB vaccination.

Clinical presentation and prognostic factors in sodium monofluoroacetate intoxication

BACKGROUND

The diagnosis of sodium monofluoroacetate intoxication in humans is usually based on a history of ingestion and clinical findings. Although several previous reports have described the clinical course and outcome of patients who ingested this drug, prognostic indicators of short-term survival are not available.

METHODS

A retrospective study of 38 consecutive cases of sodium monofluoroacetate poisoning at the National Cheng Kung. University Hospital, 1988-1993, to analyze the clinical findings and to predict mortality.

RESULTS

Seven of 38 patients (18%) died. The most common symptom was nausea or vomiting (74%). The most frequent ECG finding was nonspecific ST-T and T wave abnormalities (72%). Hypocalcemia (42%) and hypokalemia (65%) were the common electrolyte abnormalities. The clinical and laboratory characteristics were compared for the survival and mortality groups. Significant differences in hypotension, respiratory rate, pulse rate, creatinine, potassium, elevated alanine aminotransferase, pH, PCO2, APACHE II score, and subjective respiratory distress were noted. Discriminant analysis identified hypotension, increased serum creatinine, and decreased pH as the most important predictors of mortality, with sensitivity of 86% and specificity of 96%.

CONCLUSIONS

Hypotension and the early onset of metabolic acidosis and increased serum creatinine are associated with poor short-term survival. These prognostic variables can be useful in the care of patients with suspected sodium monofluoroacetate intoxication. It is suggested that all such patients should be observed intensively for at least 48 h.

Biomarkers: a molecular approach to cancer epidemiology

The rapidly evolving field of molecular epidemiology represents a paradigm shift in medical research, illustrating the convergence of basic, clinical and epidemiologic research, as well as the application of laboratory methods to population studies. As a complement and improvement to traditional epidemiologic approaches, the use of biomarkers offers more accurate exposure assessment at an individual level, better understanding of the biological mechanism of carcinogenesis by tracking a continuum of events between exposure and disease, as well as the ability to discern host or genetic factors that may account for variations in cancer susceptibility among individuals or ethnic populations. Further, biomarkers have also proved useful in cancer diagnosis and prognosis. This article attempts to review the latest progress in molecular cancer epidemiology and to summarise the current state of research in Singapore.

Molecular diagnosis of nasopharyngeal carcinoma: a review

The various antigen complexes of the Epstein-Barr virus (EBV) are broadly classified as the viral capsid antigen (VCA), diffuse early antigen (EA-D), restricted early antigen (EA-R), membrane antigen (MA) and the Epstein-Barr nuclear antigen (EBNA). The different EBV-related diseases may be differentiated according to the reactivity of these different classes of antibodies towards the various classes of antigen complexes. However, with the recent development of molecular biology, it is now known that the individual polypeptides of the different EBV antigen complexes can be used as serological markers for the detection of nasopharyngeal carcinoma (NPC). Among the useful serological markers which have been used in enzyme-linked immunosorbent assay (ELISA) for the detection of NPC are the gp125 from the VCA complex (IgA), pp58 from the EA-D complex (IgG), ribonucleotide reductase (IgG and IgA), DNase (IgA) and thymidine kinase (IgA) from the EA-R complex, gp 250/200 from the MA complex (IgA) and the ZEBRA antigen (IgA).

C4 and 21-hydroxylase gene deletions in nasopharyngeal carcinoma among the Chinese

Deletions around the C4 and 21-hydroxylase (21-OH) gene region occur among the Chinese, and C4B together with 21-OHA deletion is the most common. This deletion was found to be strongly associated with human leucocyte antigen (HLA) B58 DRB1*0301, particularly with DRB1*0301. The initial observation of a high frequency of this deletion in nasopharyngeal carcinoma (NPC) was secondary to the B58 DR3 association with NPC. A deletion of 21-OHA alone was observed to be associated with HLA B13 DRB1*1501.

Tumour suppressor p53 and Rb genes in human hepatocellular carcinoma

Aberrations of the p53 and Rb tumour suppressor genes were examined in 12 human hepatocellular carcinoma (HCC)-derived cell lines from different geographic areas and 9 local HCCs by restriction fragment length polymorphisms (RFLP), polymerase chain reaction-single-strand conformation polymorphisms (PCR-SSCP) and DNA sequencing. The relationships between genetic changes and hepatitis B virus (HBV) DNA integration in samples were compared. None of the cell lines and tumours showed structural changes in the Rb gene, while 6 cell lines and 2 tumours had mutation or deletion in exons 5 to 8 of p53. Mutations include an AGG --> AGT (Arg --> Ser) transversion at codon 249 in PLC/PRF/5 and Mahlavu, an AAT --> AAA (Asn --> Cys) transversion at codon 200 in TONG/HCC, an AAG --> GAG (Lys --> Glu) transition at codon 139 in HCC-T, a CAT --> CGT (His --> Arg) transition at codon 214 in SC4, and a CCC --> CTC (Pro --> Leu) transition at codon 250 in SC8. In Huh4, an 18-bp deletion from codon 264 to 270 resulted in loss of Leu-Gly-Arg-Asn-Ser-Phe from the amino acid sequences 265 to 270, whereas Hep3B had a 7-kb deletion after exon 7 of p53. Our data indicate that whereas Rb may not have pleiotropic effects on HCC, p53 aberrations are frequently involved in hepatocarcinogenesis. Further, HBV infection appears to be unrelated to the micro-genetic changes of p53. The G to T codon-249-mutation is consistent with HCCs arising from areas at high risk for both aflatoxin B1 (AFB1) exposure and HBV infection.

Inhibition by intrathecal prazosin but not yohimbine of fentanyl-induced muscular rigidity in the rat

We evaluated the effect of intrathecally administered prazosin, alpha 1-adrenoceptor antagonist, or yohimbine, alpha 2-adrenoceptor antagonist, on fentanyl-induced muscular rigidity. Adult, male Sprague-Dawley rats were anesthetized with ketamine and were under mechanical ventilation. Fentanyl given intravenously (100 micrograms/kg) or microinjected into the bilateral locus coeruleus (LC) (2.5 microgram/50 nl) consistently evoked a significant increase in the electromyographic activity recorded from the sacrococcygeus dorsalis lateralis muscle. This implied muscular rigidity was appreciably antagonized by prior intrathecal (10 microliters) administration of prazosin (5 or 10 nmol), but not equimolar dose of yohimbine. These results suggest that the spinal alpha 1-adrenoceptors in the coerulospinal noradrenergic pathway play a key role in fentanyl-induced muscular rigidity.

Participation of presynaptic noradrenergic fibers in the suppression of alpha 2-adrenoceptor activity by substance P at the nucleus reticularis gigantocellularis of the rat

We applied reverse microdialysis and high performance liquid chromatography (HPLC) analysis to evaluate the participation of presynaptic noradrenergic neurotransmission in the suppression by substance P (SP) of alpha 2-adrenoceptor activity at the nucleus reticularis gigantocellularis (NRGC) in Sprague-Dawley rats anesthetized with pentobarbital sodium. Microinfusion of SP (600 microM/min) into the NRGC through a stereotaxically positioned microdialysis probe attenuated the hypotensive and bradycardiac actions of the alpha 2-adrenoceptor agonist, guanabenz (100 micrograms/kg, i.v.). This inhibitory effect correlated positively with the time course of elevation in the estimated extracellular concentrations of SP and norepinephrine (NE) in the NRGC. Direct microinfusion of NE (50 nM/min) into the NRGC also lessened the cardiosuppressant effects of guanabenz. These circulatory and NE responses to SP were, however, significantly blunted in rats in which the noradrenergic innervation in the NRGC was depleted with N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride (DSP4) pretreatment. Microinfusion of NE into the NRGC of DSP4-pretreated animals restored the attenuation of guanabenz-induced cardiovascular suppression. These results suggest that SP may depress the activity of alpha 2-adrenoceptor at the NRGC that are involved in circulatory regulation by increasing the extracellular concentration of NE via a presynaptic modulation of noradrenergic neurotransmission.

Bacterial contamination of hospital disinfectants

A study to determine contamination of diluted disinfectants at different points in preparation and use in 6 Malaysian hospitals was done using the in-use test. A growth of > or = 250 organisms/ml was taken as an indication of contamination. A total of 342 (7.9%) of the 4316 freshly diluted samples collected from disinfectant bottles in the pharmacy were found to be contaminated. The bacterial isolates obtained were Pseudomonas spp. (42.4%), Moraxella spp. (22.0%), Flavobacterium spp. (11.6%) and Enterobacter spp. (4.2%). Three hundred and sixty seven out of 2278 ward stock were contaminated. The isolates were Pseudomonas spp. (48.6%), Moraxella spp. (17.8%), Acinetobacter spp. (8.9%) and Flavobacterium spp. (7.0%). Of the 9265 disinfectants in-use, 1519 (16.4%) were contaminated. Among the organisms isolated were Pseudomonas spp. (44.3%), Bacillus spp. (13.0%), Enterobacter spp. (9.5%) and Acinetobacter spp. (7.3%). The results indicated a high level of contamination of diluted disinfectants prepared in the pharmacy, stored and used in the wards. This gave a high index of suspicion that recommendations for cleaning of disinfectant containers before refilling, handling of diluted stock solutions and using of disinfectants were not closely adhered to. Standard disinfection procedures outlined in the disinfection and sterilization policy by the Ministry of Health should therefore be followed.

Disinfection: gaps between recommended and actual practice

Basic practices on disinfection was surveyed in 6 hospitals using an observation and interview checklist. Two surveys were done, one pre-(first survey) and one post-intervention (second survey). The disinfection and sterilization policy of the Ministry of Health was not available in 66 (70.2%) and 12 (13%) of the units in the first and second survey respectively. In the second survey, staff in all the units washed disinfectant containers before refilling compared with 41.5% of the units in the first survey. Dilution of disinfectants not recommended was found to be used in the first survey. Storing cleaned and sterile items in disinfectants, using disinfectant as a substitute for sterilization of autoclavable items and not decontaminating spillages were some of the wrong practices observed. Considerable improvements were made in the second survey. Improper usage of disinfectants was also indicated by failure of the in-use test. Rate of failure of disinfectants in-use decreased from 11.6% in the first survey to 5.0% in the second survey. To ensure proper disinfection practices, a comprehensive training program on disinfection is required for nurses and attendants.

Effects of propofol on nociceptive response and power spectra of electroencephalographic and systemic arterial pressure signals in the rat: correlation with plasma concentration

We applied simultaneous spectral analysis of electroencephalographic (EEG) and systemic arterial pressure signals in Sprague-Dawley rats to monitor the status of consciousness and cardiovascular functions during intravenous anesthesia with propofol and to assess their correlations with plasma propofol concentration. Our results support the hypothesis that a 'threshold' plasma concentration (1.7-1.8 micrograms/ml) exists for propofol anesthesia. This threshold level, we further showed, may be attained by both i.v. bolus injection and continuous infusion, although the pharmacokinetic profiles, as well as EEG and hemodynamic correlates, may be different. Continuous, on-line power spectral analysis of EEG signals revealed that the degree of reduction in the power density of the theta and delta bands and root mean square value paralleled the level of anesthesia. Significant suppression of both alpha and beta components occurred only concomitant with EEG burst suppression. At the subanesthetic dose, i.v. infusion of propofol increased preferentially the power density of the theta and delta bands, suggesting the validity of including sedation as a nonhypnotic therapeutic application of propofol. We also found that appreciable cardiovascular suppression took place only upon anesthetic doses of propofol. Power spectral analysis of systemic arterial pressure signals indicated that this was accompanied by a progressive depression of spectral parameters that signify peripheral vascular resistance and baroreceptor reflex response.

Influence of gender and age at onset on the HLA associations in Chinese with insulin-dependent diabetes mellitus

IDDM in Singaporean Chinese was associated with HLA B58, DRB1*0301, DQB1*0201, and joint occurrences of DRB1*0301/*0901 and DRB1*0301/*04. Of the DR4s the frequencies of DRB1*0401, *0404, and *0405 were higher and *0406 was lower in patients compared to controls. DRB1*0301/*0901 was observed mainly in female patients and the frequency showed an inverse relationship with age at onset, whereas DRB1*0301/*04 was observed mainly in male patients and also showed an inverse relationship with age at onset. DRB1*1202 showed an increasing frequency with age at onset. IDDM patients had a higher frequency of homozygous NAsp57 DQ beta chains and a lower frequency of homozygous Asp57 DQ beta chains compared to controls, especially in younger onset patients.

Significance of urinary tissue polypeptide specific antigen (TPS) determination in patients with urothelial carcinoma

Tissue polypeptide specific antigen (TPS) is the M3 epitope of the tissue polypeptide antigen, and a specific epithelial proliferation marker. To examine the benefit of urine TPS (UTPS) measurement in the diagnosis and classification of biological properties of transitional cell carcinoma (TCC), a radioimmunoassay of U-TPS was measured in patients with active TCC (n = 56), at tumor-free status (n = 36), with inflammatory urological disease (n = 44), and age-sex adjusted normal subjects (n = 75). Both neoplastic and inflammatory urological diseases had an increase in U-TPS levels (U/gm creatinine) compared to normal individuals (p = 0.0005), while it normalized in tumor-free condition (p = 0.007). For patients with active TCC, a strong positive association was observed between U-TPS values and both histological grading (p = 0.05) and positive cytology (p = 0.05). U-TPS levels were significantly higher in the presence of nodal or systemic metastasis (p = 0.008 by ANOVA test). Measurement of U-TPS appeared to be an indicator of poor outcome for patients with bladder cancer (p = 0.05 by t test) for a mean follow-up of 26 months. The results indicate that determination of U-TPS can be a supplement in assessing the biological properties of TCC, and may be helpful in identifying patients who need meticulous peri-operative staging survey.

Involvement of potassium and calcium channels at the locus coeruleus in fentanyl-induced muscular rigidity in the rat

Previous work from our laboratory suggested that Go alpha protein at the locus coeruleus (LC) may be involved in the signal transduction process that underlies muscular rigidity induced by fentanyl. The present study further evaluated the roles of K+ and L-type Ca2+ channels, gating of which is known to be associated with activation of Go alpha protein, in this process, using Sprague-Dawley rats anesthetized with ketamine. Bilateral microinjection into the LC of tetraethylammonium chloride (100 or 200 pmol), a K+ channel blocker, and S(-)-Bay K 8644 (0.5 nmol), a Ca2+ channel activator, produced significant antagonization of the EMG activation elicited by fentanyl (100 micrograms/kg, i.v.), as recorded from the sacrococcygeus dorsalis lateralis muscle. On the other hand, local application to the bilateral LC of diazoxide (10 or 20 nmol), an ATP-dependent K+ channel activator, and nifedipine (0.25 or 0.5 pmol), a L-type Ca2+ channel blocker, was ineffective in blunting fentanyl-induced muscular rigidity. These results suggest that activation of K+ channels and/or inhibition of L-type Ca2+ channels secondary to triggering of the Go alpha protein at the LC may underlie the signal transduction process in the mediation of fentanyl-induced muscular rigidity.

HLA-A2 allelic microvariants in nasopharyngeal carcinoma

HLA-A2-positive nasopharyngeal carcinoma (NPC; n = 38) and normal control (n = 51) populations were analysed by high-resolution oligotyping to identify A2 allelic microvariants. Within the control group, A*0207 was found to be the most common allele, accounting for 50% of the A2 frequency in normals. In contrast, this allele was found to be present in only 23% of NPC cases, suggesting a protective effect. Of these 9 NPC patients with A*0207, all were associated with B46, unlike in the control group, where it can be found associated with non-B46 antigens. Another allele, A*0201, which was thought to be protective against NPC was in fact present in 39.5% of NPC patients, more than twice the frequency in controls. These data confirm that A*0201 is not a protective allele for NPC, and other factors such as the A*0207, non-B46 haplotype are of greater importance.

Power spectral analysis of electroencephalographic desynchronization induced by cocaine in rats: correlation with evaluation of noradrenergic neurotransmission at the medial prefrontal cortex

We applied continuous, on-line and real-time spectral analysis of electroencephalographic (EEG) signals and microdialysis to evaluate the possible participation of noradrenergic neurotransmission at the medial prefrontal cortex (mPFC) in EEG desynchronization induced by cocaine. Male Sprague-Dawley rats that were under chloral hydrate anesthesia were used. Intravenous administration of cocaine (1.5 or 3.0 mg/kg) dose-dependently induced EEG desynchronization, as represented by a decrease in root mean square (RMS) and an increase in mean power frequency (MPF) value of the EEG signals. Power spectral analysis further revealed that whereas both doses of cocaine promoted a reduction in the alpha (8-13 Hz), theta (4-8 Hz), and delta (1-4 Hz) components, the lower dose of cocaine decreased, and the higher dose increased the beta band (13-32 Hz). Microdialysis data indicated an elevation in extracellular concentration of norepinephrine at the mPFC that paralleled temporally and correlated positively with the maximal effect of cocaine on EEG activity. Bilateral microinjection of the selective noradrenergic neurotoxin, DSP4 (50 micrograms), or equimolar concentration (500 pmol) of the alpha 1-adrenoceptor antagonist, prazosin, or alpha 2-adrenoceptor antagonist, yohimbine, into the mPFC significantly blunted the decrease in delta component (prazosin) or both delta and theta components (DSP4 or yohimbine) of EEG activity by the lower dose of cocaine. On the other hand, the same pretreatments appreciably antagonized the increase in beta band by cocaine at 3.0 mg/kg. The potency of the antagonism by yohimbine, however, was higher than prazosin. These results suggest that cocaine may elicit EEG desynchronization via noradrenergic neurotransmission, and that alpha 2-adrenoceptors, and to a lesser extent, alpha 1-adrenoceptors, at the mPFC may be involved in the subtle dose-dependent changes in individual EEG spectral components.

Inhibition of staphylococcal enterotoxin-driven lymphocyte proliferation by anti-MHC class II monoclonal antibody

Staphylococcal enterotoxins (SE) bind to major histocompatibility complex (MHC) class II molecules and the V beta region of T cell receptors (TCR) and subsequently induces T cell proliferation. This mitogenicity is the basis of pathological effects seen in food poisoning and toxic shock syndrome. Toxin-specific monoclonal antibodies have previously been shown to be effective in blocking toxin stimulated T cell responses. In this study, a monoclonal antibody, 52BL1, was found to be a potent inhibitor of SEA-, SEB-, SEC1-, SED-, and SEE-induced lymphocyte proliferation assays, which indicates that a single anti-HLA (human leukocyte antigen) class II antibody is effective in blocking the biological effects of these toxins. These results demonstrate the possibility of using anti-HLA class II antibodies in a clinical setting as an antagonist to staphylococcal enterotoxinmediated pathogenesis.

Adenoma-carcinoma sequence: a reappraisal with immunohistochemical expression of ferritin

To examine the biological significance of ferritin (FRN) expression, a retrospective immunohistochemical study was performed in normal colonic mucosae (n = 8), adenomas (n = 88), and colorectal carcinomas (n = 104). FRN was present in some epithelia in the crypt base of normal colonic mucosae. Significant cytoplasmic staining for FRN was revealed in 26 (29.5%) cases of adenoma and 54 cases (51.9%) of adenocarcinoma. The cancer cells had a higher proportion of FRN expression than those of adenomas or non-neoplastic mucosae (P < 0.001). Expression of FRN showed a positive association with the degree of dysplasia (P = 0.039) and the distal location of adenoma (P = 0.013). FRN expression tended to be associated with the tumor size (P = 0.083), but no substantial difference was observed among the histologic types of adenoma (P = 0.754). The results suggest that cytoplasmic FRN expression is associated with cellular proliferation. The proliferative index shows a significant difference through the adenoma-carcinoma sequence. Further investigation is necessary to clarify the clinical implication of FRN expression in tumor cells and normal-appearing mucosae.

T-cell receptor gene expression in tumour-infiltrating lymphocytes and peripheral blood lymphocytes of patients with nasopharyngeal carcinoma

The T-cell receptor (TCR) repertoire expression of tumour-infiltrating lymphocytes (TILs) from 19 nasopharyngeal carcinoma (NPC) biopsies was compared with those of lymphocytes from 18 control nasopharyngeal biopsies. mRNA was extracted from these lymphocytes and the cDNA transcribed. A panel of 18 V alpha- and 21 V beta-specific primers was used to detect the TCR gene use from cDNA. The use of V alpha and V beta genes was restricted in TILs compared with lymphocytes from biopsies. The frequencies of V alpha 2, V alpha 3, V alpha 9, V alpha 10, V alpha 11, V alpha 13, V alpha 14, V alpha 15, V beta 11, V beta 15 and V beta 20 were decreased and the frequencies of V alpha 10 [Pc = 0.04; relative risk (RR) = 0.05], V alpha 11 (Pc = 0.02; RR = 0.07), V alpha 13 (Pc = 0.002; RR = 0), V alpha 14 (Pc = 0.04; RR = 0.05), V beta 14 (Pc = 0.001; RR = 0.03) and V beta 20 (Pc = 0.001; RR = 0.03) remained significantly reduced after correction for the number of families typed. The frequency of V alpha 17 was higher in NPC biopsies than in NPC PBLs (P = 0.05), and the frequency of V beta 15 was lower in NPC biopsies than in NPC PBLs (P = 0.02). The frequencies of V alpha 17 and V alpha 18 in HLA-B46+ patients were significantly lower (P = 0.009; P = 0.044) than in B46+ controls. The results suggest that the restriction of TCR gene use in NPC patients may be important in NPC pathogenesis.