Fite stain positivity in Rhodococcus equi: yet another acid-fast organism in respiratory cytology--a case report.

Rhodococcus equi is an aerobic Gram-positive and acid-fast coccobacillus that may cause cavitary pneumonia in immunocompromised hosts such as HIV-infected patients. Numerous Grocott's methenamine silver (GMS)-positive organisms were initially noted on the direct smear; a minor number of acid-fast organisms were seen in the Thin-Prep slide. Since the abundant mucous material with the attached organisms seen in conventional smears may be lost in liquid-based preparations, more sensitive stains such as Fite, as well as a more diligent search for organisms, is needed. This case illustrates the importance of careful selection and evaluation of special stains in sputum specimens.

Effect of chronic treatment with the GABA transaminase inhibitors gamma-vinyl GABA and ethanolamine O-sulphate on the in vitro GABA release from rat hippocampus.

1. The effects of 2, 8 and 21 day oral treatment with the specific gamma-aminobutyric acid transaminase (GABA-T) inhibitors gamma-vinyl GABA (GVG) and ethanolamine O-sulphate (EOS) on brain GABA levels, GABA-T activity, and basal and stimulated GABA release from rat cross-chopped brain hippocampal slices was investigated. 2. Treatment with GABA-T inhibitors lead to a reduction in brain GABA-T activity by 65-80% compared with control values, with a concomitant increase in brain GABA content of 40-100%. 3. Basal hippocampal GABA release was increased to 250-450% of control levels following inhibition of GABA-T activity. No Ca2+ dependence was observed in either control or treated tissues. 4. GVG and EOS administration led to a significant elevation in the potassium stimulated release of GABA from cross-chopped hippocampal slices compared with that of controls. Although stimulated GABA release from control tissues was decreased in the presence of a low Ca2+ medium, GVG and EOS treatment abolished this Ca2+ dependency. 5. GABA compartmentalization, Na+ and Cl- coupled GABA uptake carriers and glial release may provide explanations for the loss of the Ca2+ dependency of stimulated GABA release observed following GVG and EOS treatment. 6. Administration of GABA-T inhibitors led to increases in both basal and stimulated hippocampal GABA release. However, it is not clear which is the most important factor in the anticonvulsant activity of these drugs, the increased GABA content 'leaking' out of neurones and glia leading to widespread inhibition, or the increase in stimulated GABA release which may occur following depolarization caused by an epileptic discharge.

Extracellular levels of glutamate and aspartate in the entopeduncular nucleus of the rat determined by microdialysis: regulation by striatal dopamine D2 receptors via the indirect striatal output pathway?

This study used intracerebral microdialysis to monitor the outputs of excitatory amino acids in the entopeduncular nucleus (EPN) of conscious or halothane-anaesthetized rats, in an attempt to obtain direct biochemical evidence for the theory that neuronal inputs to the EPN by the indirect striatal output pathway are glutamatergic and regulated primarily by dopamine D2 receptors in the striatum. In dopamine-intact animals, both glutamate and asparate were readily detectable in EPN dialysates. Recoveries of both amino acids were increased bilaterally by local perfusion with veratridine (100 microM, given under halothane anaesthesia), pretreatment with reserpine (4 mg/kg, i.p., 24 h beforehand), unilateral pretreatment of the medial forebrain bundle with 6-OHDA (8 microg/4 microl), and by the systemic (1 mg/kg, i.p.) or bilateral intrastriatal (7 microg/0.5 microl under halothane anaesthesia) administration of the dopamine D2 receptor antagonist haloperidol, but not raclopride (2 mg/kg, i.p.). The dopamine D1 receptor antagonist SCH 23390 was ineffective both systemically (0.25 mg/kg, i.p.) and intrastriatally (0.125 microg/0.5 microl/side), as also were control intrastriatal injections of saline (0.5 microl/side). By contrast, the dopamine D2/3 receptor agonist quinpirole (4 mg/kg, i.p.) lowered the outputs of glutamate and aspartate in the EPN of reserpine-treated and normal individuals, whilst the dopamine D1 receptor agonist SKF 38393 (30 mg/kg, i.p.) was inactive; however, both drugs caused behavioural arousal. The dopamine D2/3 receptor agonist RU 24213 reversed reserpine-induced akinesia, yet paradoxically increased glutamate (not aspartate) output in the EPN still further. The combination of benserazide (30 mg/kg, i.p.) and L-DOPA (50 mg/kg, i.p.) evoked intense contraversive circling in unilaterally 6-OHDA-lesioned rats, together with a drop in EPN glutamate (but not aspartate) output in the intact but not lesioned hemisphere. These results offer biochemical support for the hypothesis that excitatory neurones innervating the EPN via the indirect striatal output pathway, may utilise glutamate and/or aspartate as their neurotransmitter. They further endorse the view that the EPN receives information from striatal D2 and not D1 receptors via excitatory synapses, which become hyperactive following dopamine depletion or inactivation, and which are subject to control by the contralateral as well as by the ipsilateral hemisphere. The results obtained with RU 24213 and L-DOPA, however, indicate that dopaminergic behaviours can also occur independently of glutamate or aspartate release in the EPN.

AMPA receptors modulate extracellular 5-hydroxytryptamine concentration and metabolism in rat striatum in vivo.

We have investigated the effects of infusing the excitatory amino acid agonist alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) on extracellular levels of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in rat striatum using in vivo microdialysis. AMPA (50-500 microM) caused a concentration-dependent increase in extracellular 5-HT, while having the converse effect on 5-HIAA. At the highest agonist dose the decrease in dialysate 5-HIAA was followed by a significant increase in this metabolite. Two hundred micromolar 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), a competitive non-NMDA glutamate receptor antagonist, reversed the effects of a 100 microM AMPA on dialysate 5-HT and 5-HIAA. Co-infusion of AMPA with tetrodotoxin (TTX) abolished the effects of 100 microM AMPA, but only partially reversed the effect of 500 microM AMPA on 5-HT release. We have also investigated whether AMPA receptor desensitization, a well documented event, plays a role in AMPA receptor modulation of striatal 5-HT release. Diazoxide (500 microM), a drug which prevents AMPA receptor desensitization, failed to augment the effect of 100 microM AMPA on 5-HT release. Diazoxide alone significantly decreased 5-HT release, as did the drug cromakalim (100 microM), probably as a result of their common action as activators of ATP-dependent K+ channels. It is concluded that AMPA receptors play a role in regulating both 5-HT release and metabolism in rat striatum. However, AMPA receptor desensitization does not appear to play a role in this process in this structure.

Effects of chronic oral treatment with GABA-transaminase inhibitors on the GABA system in brain, liver, kidney, and plasma of the rat.

The inhibitory neurotransmitter gamma-aminobutyric acid (GABA) is not solely located in the CNS, it and the enzymes responsible for its synthesis (glutamic acid decarboxylase, GAD, EC 4.1.1.15) and catabolism (GABA-transaminase, GABA-T, EC 2.6.1.19) are also present in non-neuronal organs. Following 2, 8 and 21 day oral administration of ethanolamine-O-sulphate (EOS) and gamma-vinyl GABA (GVG), two irreversible inhibitors of GABA-T, the GABA content and activities of GAD and GABA-T in rat brain, liver and kidney, and the GABA content of plasma were determined: GABA-T activity was significantly decreased (over 80%) in liver, brain and kidney, although there was 2-3 times the residual activity left in the brain compared with the peripheral organs. GABA content was subsequently significantly elevated in the liver (300-1500%), plasma (200-300%) and brain (200-300%), although, surprisingly, the kidney GABA content was reduced (by 60-70%) compared with control. GAD activity was decreased following 8 day treatment in liver and brain. Kidney GAD was reduced at all time points. These two compounds are anticonvulsant, GVG is used clinically for the treatment of epilepsy but it seems that these drugs have significant peripheral effects.

Effects of preoperative chemotherapy on the morphology of resectable breast carcinoma.

We examined pathologic specimens from 43 patients with Stage T1-T3 lesions who were treated preoperatively with four cycles of doxorubicin/cyclophosphamide, followed by segmentectomy/mastectomy and axillary node dissection (the National Surgical Adjuvant Breast and Bowel Project B-18 protocol). Specimens from 46 patients treated post-operatively with the same regimen served as histologic controls. The initial diagnosis was made by core needle biopsy (28%) or by fine-needle aspiration (72%). Six changes were noted in 36 patients (84%), with complete regression in 10, but histologic evidence of regression and characteristic cytologic changes occurred in only one-half of the 43 patients, and there was poor correlation between histologic regression and clinical response; (2) an increased nuclear grade occurred in 32% of the cases; (3) unusually prominent intraductal and/or intralymphatic tumor was observed in 40%; (4) histologic evidence of tumor regression in axillary lymph nodes was noted in nine cases; (5) regressive changes also occurred in non-neoplastic breast tissue and in lymphoid populations of lymph nodes; and (6) difficulty was noted in evaluating residual atypical intraductal proliferations. These findings add a quantitative dimension to previously published descriptions and emphasize the need for pathologic staging in these patients. In addition, they provide histopathologic evidence of downstaging in axillary lymph nodes and of relative treatment resistance by intraductal and intralymphatic tumor.

Apocrine metaplasia in gynecomastia by fine needle aspiration as a possible indicator of anabolic steroid use. A report of two cases.

BACKGROUND: The fine needle aspiration finding of apocrine metaplasia in association with the usual cytologic findings of gynecomastia is distinctly unusual. Previous reports do not mention any historical clinical association. CASES: Two otherwise healthy adult males presented for fine needle aspiration (FNA) of new-onset breast masses. Both showed apocrine metaplasia associated with the typical clinical and cytologic features of gynecomastia on FNA. Additional questioning revealed that both patients reported recent anabolic steroid use as part of their body-building routines. CONCLUSION: The fine needle aspiration finding of apocrine metaplasia in association with the usual cytologic and clinical findings of gynecomastia in otherwise healthy adult males without a medication history may be an indicator of illicit anabolic steroid use. Anabolic steroid use often has serious consequences, so its possibility should prompt further evaluation by the patient's clinician.

Tetanus toxin-induced effects on extracellular amino acid levels in rat hippocampus: an in vivo microdialysis study.

Tetanus toxin is a potent neurotoxin that is widely considered to produce its effect through impairment of inhibitory neurotransmission. We report the effect of a single unilateral intrahippocampal injection of tetanus toxin on extracellular levels of neuroactive amino acids in freely moving rats, at times ranging between 1 and 7 days posttreatment. Tetanus toxin treatment did not alter extracellular levels of aspartate, glutamate, and taurine at any time during the study. However, although extracellular GABA levels were unaffected by toxin injection 1, 2, and 3 days after treatment, they were reduced (45 +/- 8% of contralateral vehicle-injected level) at day 7. Challenge with a high K+ concentration, 7 days after treatment, produced elevations in extracellular levels of taurine and GABA in both vehicle- and toxin-injected hippocampi, with evoked levels of GABA being lower in the toxin-treated side (39 +/- 16% of contralateral vehicle-injected level). Aspartate and glutamate levels were not increased by high-K+ infusion. These findings are discussed in relation to the possible role that an imbalance in excitatory/inhibitory tone may play in the production of tetanus toxin-induced neurodegeneration.

Evidence for release of glutamic acid, aspartic acid and substance P but not gamma-aminobutyric acid from primary afferent fibres in rat spinal cord.

In vitro superfusion release experiments and autoradiography were carried out on spinal cords of neonatally capsaicin-treated rats. Electrical and chemical stimulations significantly increased the release of aspartate, glutamate and gamma-aminobutyric acid (GABA) from hemisected dorsal horn slices of vehicle-treated animals. In capsaicin-treated rats, the evoked release of aspartate, glutamate and substance P but not GABA, were significantly lower. Capsaicin (1 microM) stimulated the release of aspartate and glutamate, as reported for substance P, in control slices but this effect was not as apparent in tissues from capsaicin-treated rats. Evoked GABA release was not affected in either case. alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), kainate, dizocilpine and GABAB binding sites were highly localised in the substantia gelatinosa. Capsaicin treatment did not affect the affinity of the binding sites in all four cases but significantly reduced the density of kainate, dizocilpine and GABAB binding sites. The data suggest that capsaicin-sensitive primary afferent fibres release aspartate, glutamate and Substance P following high-intensity stimulations and that this release might be modulated by presynaptic glutamate and GABAB receptors present on these terminals.

NMDA receptor antagonists increase the release of dopamine in the substantia nigra of reserpine-treated rats.

Microdialysis of the substantia nigra pars reticulata in freely moving rats disclosed a steady release of dopamine and its metabolites which was greatly reduced after reserpine (4 mg/kg s.c.) and alpha-methyl-p-tyrosine (200 mg/kg i.p.) pretreatments. Local infusion of high K+ (100 mM) or L-3,4-dihydroxyphenylalanine (L-DOPA, 10 microM) significantly increased dialysate levels of dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC), but not homovanillic acid (HVA) in this model. Intranigral application of the non-competitive NMDA receptor antagonist dizocilpine (150 nM), or the competitive NMDA receptor antagonist R-DL-(E)-2-amino-4-methyl-5-phosphono-3-pentanoate (CGP 40116, 10 microM), via the dialysis probe, did not affect the release of dopamine or its metabolites in intact rats, but further suppressed these releases in reserpine plus alpha-methyl-p-tyrosine-treated animals. When the same amounts of dizocilpine or CGP 40116 were coinfused with L-DOPA, however, they potentiated the recovery of dopamine 12-24 times, and of DOPAC 5-10 times (but not HVA), as well as producing detectable behavioural arousal. The facilitation of dopamine formation from L-DOPA by NMDA receptor antagonists in the substantia nigra pars reticulata could explain the enhancement of L-DOPA's antiparkinsonian activity by these compounds in behavioural experiments.

Effect of lamotrigine on the electrically-evoked release of endogenous amino acids from slices of dorsal horn of the rat spinal cord.

The novel anti-epileptic, lamotrigine (LTG) has been shown to exhibit antinociceptive effects in the rat. In the present study, the effect of LTG on the electrically-evoked release of endogenous amino acids from rat isolated spinal dorsal horn slices with intact dorsal roots has been examined and compared with those of morphine in the same preparation. LTG (0.1-300 microM) inhibited the release of aspartate, glutamate and GABA in a concentration-dependent manner. The lowest concentrations of morphine (0.001-0.01 microM) enhanced the stimulated release of aspartate and glutamate while the higher concentrations inhibited their release. Stimulated GABA release was reduced in a concentration-dependent manner. The anticonvulsant was more potent at inhibiting the release of glutamate (IC50 = 20 microM) than that of GABA (IC50 = 44 microM) supporting the previous suggestion that lamotrigine is a selective inhibitor of glutamate release. This suggests that the reduction in glutamate release could be one of the mechanisms by which lamotrigine exerts its antinociceptive effect.

Diagnosis of Epstein-Barr virus associated nasopharyngeal carcinoma using fine-needle aspiration biopsy and molecular diagnostics.

Molecular technology is being utilized increasingly for diagnostic purposes by practicing pathologists. Techniques such as Southern blot, in situ hybridization, and polymerase chain reaction have recently been introduced to the clinical laboratory setting. We describe a case of nasopharyngeal carcinoma that highlights the potential utility of DNA technology to secure an accurate diagnosis of a fine-needle aspiration biopsy. In this patient, cytologic examination of a cervical lymph node aspirate strongly suggested the possibility of a nasopharyngeal carcinoma. Needle aspirate material was submitted for molecular genetic detection of the Epstein-Barr virus (EBV) genome. Nine micrograms of DNA were isolated, and the presence of clonal EBV DNA was detected by the Southern blot technique. The presence of clonal EBV supported the cytologic diagnosis of nasopharyngeal carcinoma. Subsequent biopsy of a nasopharyngeal mass revealed undifferentiated carcinoma, and in situ hybridization revealed that EBV was restricted to the malignant epithelial cells. This case illustrates how molecular technology can provide new information that is useful in diagnostic cytopathology.

Impulse-dependent and tetrodotoxin-sensitive release of GABA in the rat's substantia nigra measured by microdialysis.

gamma-Aminobutyric acid (GABA) release in the rat substantia nigra pars reticulata (SNR) was studied by microdialysis coupled with high-performance liquid chromatography and fluorimetric detection. Electrical stimulation of striatonigral axons in the internal capsule (IC) increased nigral GABA release in conscious and halothane-anaesthetized rats. This was prevented by intranigral infusion of tetrodotoxin (TTX) while basal GABA release was unaffected. Calcium-free, cobalt-containing (2 mM CoCl2) artificial cerebrospinal fluid reduced basal GABA overflow but not that evoked with high K+ (100 mM). Extracellular levels of glutamate (GLU) and taurine (TAU) were not modified by IC stimulation, TTX or 0 Ca2+ although high K+ promoted GABA and TAU release but not that of GLU. These data demonstrate an impulse-and sodium-dependent release of GABA from nigral afferent neurones which contribute little to the extracellular concentration of GABA under steady-state conditions.

alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptors modulate dopamine release in rat hippocampus and striatum.

The effects of infusing the glutamate receptor agonist alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) on the release of dopamine (DA) has been studied in rat hippocampus and striatum in vivo. In hippocampus, AMPA (1-10 microM) produced a dose related increase in dialysate DA, but at 100 microM AMPA a sustained decrease in extracellular DA was observed. However, when samples were collected at 5-min intervals 100 microM AMPA infusion revealed a brief increase in hippocampal dialysate DA. Infusion of 100 microM AMPA and 500 microM diazoxide, which blocks AMPA receptor desensitization, led to a marked increase in extracellular DA, as did diazoxide alone, although to a lesser extent. The AMPA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3,-dione (CNQX; 200 microM) reversed the effect of AMPA and/or diazoxide infusion on dialysate DA and when infused alone, CNQX also decreased hippocampal dialysate DA. AMPA (50-500 microM) increased striatal DA release. The effect of AMPA on extracellular DA was reversed by CNQX (200 microM). Diazoxide infusion caused a decrease in striatal DA release, and this was not affected by CNQX. These data suggest that hippocampal, but not striatal AMPA receptor desensitization may play a role in regulating DA release.

The effect of chronic treatment with the GABA transaminase inhibitors gamma-vinyl-GABA and ethanolamine-O-sulphate on the in vivo release of GABA from rat hippocampus.

The effects of chronic treatment with the specific, mechanism-based, irreversible inhibitors of 4-aminobutyrate aminotransferase (EC 2.6.1.19; GABA transaminase), ethanolamine O-sulphate (EOS), and 4-aminohexenoate [vigabatrin; gamma-vinyl-GABA (GVG)] on the extracellular concentrations of GABA in the hippocampus have been studied using in vivo microdialysis in conscious animals. Oral dosing [3 mg/ml of drinking water, giving doses of GVG of 194 +/- 38 mg/kg/day and of EOS of 303 +/- 42 mg/kg/day (mean +/- SD)] was followed by microdialysis at 2, 8, and 21 days. The basal outflow of GABA (in the range of approximately 1-2 pmol/30 microliters/30-min sample) after 2 and 8 days of treatment was not significantly different from that in control animals, but the 21-day treatment gave significant rises in the extracellular GABA concentration (up to approximately 6-8 pmol/30 microliters/30-min sample). Both inhibitors gave similar results. Depolarisation with 100 mM K+ gave large increases in GABA release in control (approximately 20-60 pmol/30 microliters/30-min sample) and treated animals. The 8- and 21-day-treated animals showed significant increases in the stimulated release compared with control animals (approximately 80-100 pmol/30 microliters/30-min sample). Excluding Ca2+ had no significant effect on either basal or stimulated release. The significant increases in K(+)-evoked release of GABA show that the increased intracellular pool of GABA is available for release, and this may be related to the anticonvulsant action of these compounds.

Minimally invasive Paget's disease of the vulva with extensive lymph node metastases.

Optimal treatment for intraepithelial and invasive Paget's disease of the vulva has been previously evaluated. The treatment of disease with minimal invasion (< or = 1 mm) represents an even greater dilemma. We report a case of Paget's disease of the vulva with 1-mm depth of invasion presenting with extensive inguinofemoral lymph node metastases documented by fine-needle aspiration biopsy.

Tonic desensitization of hippocampal alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors regulates 5-hydroxytryptamine release in vivo.

Strong evidence implicates glutamate as an excitatory neurotransmitter in the central nervous system. In the present study we have investigated the effects of different concentrations of the excitatory amino acid agonist alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid on release of 5-hydroxytryptamine in rat hippocampus using in vivo microdialysis. Infusion of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid at 1 microM led to an increase in dialysate 5-hydroxytryptamine. In contrast 100 microM alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid decreased extracellular 5-hydroxytryptamine, collected in 30 min samples, and this decrease was sustained for several hours. alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor desensitization is well documented in vitro, and is reversed by the drug diazoxide. We therefore studied the possibility that this was occurring in hippocampus in vivo. Collection of dialysates at 5 min time intervals revealed a brief increase in dialysate 5-hydroxytryptamine in response to 100 microM alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, although basal level of 5-hydroxytryptamine was below the level of detection. When 100 microM agonist was co-infused with 500 microM diazoxide, a substantial and prolonged increase in dialysate 5-hydroxytryptamine was seen. Diazoxide alone was observed to cause an increase in extracellular 5-hydroxytryptamine. Diazoxide is known to active ATP-dependent K+ channels, however, cromakalim (100 microM), an activator of ATP-dependent K+ channels, reduced hippocampal 5-hydroxytryptamine release, suggesting that the effect of diazoxide is not the result of such an action.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of isonicotinic acid hydrazide on extracellular amino acids and convulsions in the rat: reversal of neurochemical and behavioural deficits by sodium valproate.

We have studied the effect of isonicotinic acid hydrazide (INH), a convulsant agent, on the extracellular levels of amino acids in the hippocampus, and the effect of sodium valproate (VPA) administration in INH-treated rats. INH (250 mg/kg) caused a rapid and sustained decrease in basal levels of GABA, and during this period convulsions of increasing severity were observed. Basal levels of glutamine, taurine, aspartate, and glutamate were unchanged by INH. When VPA was coadministered with INH, basal GABA levels were increased and no convulsions were observed. When transmitter release was evoked using 100 mM K+, the increase in dialysate GABA observed in INH-treated animals was less than that seen in controls and convulsions increased in frequency. K(+)-evoked release of glutamate and aspartate tended to be higher following INH treatment, and in the case of aspartate, this increase was significant. VPA reversed the changes in evoked release of glutamate and aspartate, and release of GABA was considerably greater than that seen in control or INH-treated rats. No drug effect on evoked changes in taurine or glutamine level was seen. These are the first data to show decreased extracellular GABA in conjunction with convulsions in freely moving animals in vivo.