Long-term enhancement of dopamine release by high frequency tetanic stimulation via a N-methyl-D-aspartate-receptor-mediated pathway in rat striatum

We studied the effects of high frequency tetanic stimulation of the striatum on the KCl (20 mM)-evoked dopamine release in rat striatal slices. The KCl-evoked dopamine release was potentiated by high frequency tetanic stimulation (10-20 Hz) of the striatum including the corticostriatal fibers, and this potentiation was observed until 3 h after high frequency tetanic stimulation. Potentiation of dopamine release after high frequency tetanic stimulation was induced not only by KCl but also by glutamate in Mg(2+)-free medium, N-methyl-D-aspartate in Mg(2+)-free medium, and by DL-alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid. 2-amino-5-phosphovalerate, 3-[(+/-)-2-carboxypiperazine-4-yl]-propyl-1-phosphonate or dibenzocycloheptaneimine, N-methyl-D-aspartate receptor inhibitors, abolished enhancement by tetanus, whereas, 6,7-dinitroquinoxaline-2,3-dione, an antagonist of DL-alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid ionotropic receptors, or L-2-amino-4-phosphonobutyrate, an antagonist of glutamate metabotropic receptors, showed no effect. Moreover, pretreatment with glutamate or N-methyl-D-aspartate in the absence of Mg2+ also facilitated dopamine release evoked by KCl concentrations. When extracellular Ca2+ was removed from the medium during pretreatment, potentiation by glutamate disappeared. We conclude that activation of N-methyl-D-aspartate receptors on dopaminergic nerve terminals in the striatum produces the long-term changes in efficacy of the response to KCl or glutamatergic agents. That is, plastical phenomena could exist at presynaptic levels between glutamatergic neurons and dopaminergic neurons in striatum.

Zinc potentiation of neurotransmission and inhibition of background cationic conductance in rat cultured hippocampal neurones

1. The facilitation by zinc (Zn2+) of neurotransmission and the mechanisms underlying it were electrophysiologically investigated in rat cultured hippocampal neurones using whole-cell voltage- and current-clamp techniques. 2. Under whole-cell voltage clamp with an intracellular solution containing CsCl as a major salt, inward postsynaptic currents were observed at -40 mV in a cell culture where a neuronal network had been formed. The postsynaptic currents appeared to be mediated by gamma-aminobutyric acid (GABA) because the inward currents were abolished when intracellular CsCl was replaced with caesium phosphate and they were blocked by bicuculline (10 microM), an antagonist to GABA-gated channels. The currents were, however, also blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 30 microM), an antagonist to non-NMDA glutamate-gated channels, suggesting a contribution of a glutamatergic mechanism to the generation of the currents. Zn2+ (10 and 100 microM) potentiated the postsynaptic currents. 3. In addition to the potentiation of the postsynaptic currents, Zn2+ shifted net membrane current at -60 mV in an outward direction. The current-voltage relationship obtained under various ionic conditions indicated that Zn2+ inhibits a current component which is mainly carried by extracellular Na+. 4. Under whole-cell current clamp, Zn2+ (10 microM) induced a small hyperpolarization (up to 20 mV), which was accompanied by potentiation of the postsynaptic potentials and spike potentials. Tests were carried out to examine whether changes in resting potential by different protocols mimic responses observed with Zn2+. Hyperpolarization induced by current injection through patch pipettes increased the amplitude of postsynaptic currents, but did not enhance the appearance of spike potentials. In contrast, when extracellular K+ concentration was decreased from 5 to 2.5 mM, cells were hyperpolarized and spike potentials of large amplitude appeared. 5. The results suggest that Zn2+ potentiates neurotransmission and inhibits a background cationic current mainly carried by extracellular Na+ under physiological conditions. The inhibition of the Na+ permeation may increase membrane excitability and thereby contribute to the potentiation of neurotransmission.

Prospective monitoring of minimal residual disease during the course of chemotherapy in patients with acute lymphoblastic leukemia, and detection of contaminating tumor cells in peripheral blood stem cells for autotransplantation

A prospective study for detecting minimal residual disease (MRD) was conducted on children with acute lymphoblastic leukemia (ALL). Thirty-nine patients (38 B-lineage ALL, one T-ALL) with TCR delta rearrangements could be followed for 21 to 44 months (mean 30.9 months) excluding four patients who died. One hundred and ninety four bone marrow (BM) samples and 13 peripheral blood stem cell (PBSC) grafts were available for detection of MRD. Initially 34 cases were treated prospectively according to the CCLSG risk-stratified protocols for ALL (ALL874 or ALL911), and five cases according to the other protocols. Conventional chemotherapy was replaced by autologous PBSC transplantation (PBSCT) in five patients, by allogenic BM transplantation (BMT) in one patient, or suspended in another patient. Twenty-nine of 32 children in whom conventional chemotherapy could be continued without interruption remain in complete remission (CR). In 24 of the 29 patients MRD became undetectable within 12 months of their diagnosis. In five cases, BM samples obtained during maintenance therapy exhibited residual leukemia cells, and yet none of them relapsed (mean follow-up period 28.6 months). Our results thus indicate that intensive maintenance therapy for patients with PCR-positive results during consolidation therapy may prevent subsequent relapse. Nine events of relapse were diagnosed in eight patients (five BM, two isolated central nervous system (CNS), one combined BM and CNS, one isolated skin relapse). An increase or a re-emergence of MRD was detected in BM samples obtained from patients prior to BM relapse, but one patient remained in CR despite reappearance of leukemic cells following a PCR-negative status. Monitoring of MRD failed to predict isolated CNS or skin relapse. PBSCT allows high-dose cytoreduction therapy for patients with refractory neoplasia. In our study, leukemic cells were identified in eight of 13 PBSC grafts harvested from five patients. Three of four children who received PBSC grafts containing leukemic cells relapsed within 6 months after PBSCT. Monitoring of MRD as part of quality control of PBSC grafts may ultimately contribute to improvements in PBSCT procedures.

Contribution of L-type Ca2+ channels to long-term enhancement of high K(+)-evoked release of dopamine from rat striatal slices

Pre-treatment with BAY K 8644, an L-type voltage-gated Ca2+ channels agonist, produced long-term enhancement (LTE) of over 2 h of high K(+)-evoked dopamine release from rat striatal slices. Exposure to BAY K 8644 under Ca(2+)-free conditions did not enhance this release. Thus, a transient activation of L-type voltage-gated Ca2+ channels followed by Ca2+ entry can trigger LTE of the evoked DA release from striatal tissues. This type of LTE in the striatum underlines the importance of presynaptic mechanisms, including L-type voltage-gated Ca2+ channels of 'long-term potentiation' expression.

Enhancement by zinc of ATP-evoked dopamine release from rat pheochromocytoma PC12 cells

The effects of zinc (Zn2+) on ATP-evoked dopamine release was investigated in rat pheochromocytoma PC12 cells. Zn2+ potentiated the dopamine release evoked by 30 microM ATP in a concentration-dependent manner over a concentration range from 3 to 300 microM. High concentration of Zn2+ (> 1 mM) inhibited the release. Zn2+ (10 microM) shifted the concentration-response curve of the ATP-evoked dopamine release to the left without affecting the maximal response. The dopamine release evoked by 40 mM KCl was not affected by Zn2+ (1-100 microM), whereas high concentration of Zn2+ ( > 300 microM) attenuated the response. The dopamine release evoked by 30 microM ATP in the presence of 10 microM Zn2+ were suppressed by suramin (30 microM), an antagonist to P2-purinoceptors, to an extent similar to that in the absence of Zn2+. Zn2+ (1-100 microM) enhanced the ATP-evoked increase in intracellular Ca2+ concentration ([Ca]i) in the cells. The Ca2+ responses to ATP in the presence and absence of Zn2+ were abolished by external Ca(2+)-depletion. Under whole-cell voltage-clamp, Zn2+ (10 microM) augmented by two-fold the peak amplitude of an inward current evoked by 30 microM ATP. Taken together, it is suggested that Zn2+ enhances the ATP-evoked dopamine release by increasing sensitivity to ATP. The enhancement may be due to the augmentation of ATP-gated Ca(2+)-influx, but not due to modulation of cellular machinery downstream to [Ca]i rise. The enhancement of the ATP-mediated responses may underlie modulation by Zn2+ of physiological functions in various types of neuronal cells.

Glutamate-evoked release of adenosine 5'-triphosphate causing an increase in intracellular calcium in hippocampal neurons

ATP evoked an increase in intracellular Ca2+ concentration ([Ca]i) in hippocampal neurons in the presence of tetrodotoxin (TTX, 3 microM), hexamethonium (C6, 100 microM), D-2-amino-phosphonovalerate (APV, 100 microM), 6-cyano-7-nitro quinoxalline-2,3-dione (CNQX, 30 microM), bicuculline (10 microM) and cadmium (Cd2+, 300 microM). The increase was blocked by suramin (100 microM), a P2-purinoceptor blocker. These results suggest that ATP evokes an increase in [Ca]i through P2-purinoceptor. As a result of measuring [Ca]i in multiple cells simultaneously, it was suggested that glutamatergic neurones connect with purinergic neurones and glutamate (10 microM) stimulated the release of ATP causing an increase in [Ca]i in postsynaptic neurones.

NMDA receptor involvement in endothelin neurotoxicity in rat striatal slices

The high K(+)-evoked dopamine release from rat striatal slices remained impaired by 50% up to 2 h after pulse exposure of the tissues to endothelin-3, under conditions of hypoglycemia/hypoxia. This striatal dysfunction was significantly improved by D-2-amino-5-phosphonopentanoic acid, a NMDA receptor antagonist, at a much lower concentration than that providing protection against NMDA-evoked dysfunction. In light of these findings, the important role of glutamatergic mechanisms, especially NMDA receptors, in mediating endothelin neurotoxicity warrants further attention.

[Fluctuations in serum antigens and antibodies in a patient with primary cutaneous aspergillosis associated with acute leukemia]

A 5-year-old girl developed cutaneous aspergillosis due to Aspergillus flavus while undergoing remission induction therapy for acute lymphocytic leukemia. Of six serum samples obtained during the acute stage of Aspergillus infection, four showed antigenemia (6.5-22.9 ng/ml) determined by enzyme-linked immunosorbent assay (ELISA). However, five serum samples obtained after treatment with amphotericin B and granulocyte-colony stimulating factor showed negative results for antigens. Sera obtained on day 17 after the detection of skin lesions showed seroconversion in precipitin antibody determined by an immunodiffusion test and in immunoglobulin (Ig) A class antibody determined by ELISA, while sera obtained on day 24 showed seroconversion of IgG and IgM class antibodies. The patient achieved complete remission of leukemia and was discharged on the 92nd day of hospitalization. No signs of disseminated or deep-seated fungal infections were present during the hospitalization. Assays for serum antigens may be of value for the early diagnosis of invasive aspergillosis. Moreover, persistently negative results for antigens in accordance with antibody responses may correlate with recovery from the infection.

[ATP as a neurotransmitter in the brain: its possibility based upon recent findings]

We discuss here possible neurotransmitter roles of extracellular ATP in the central nervous system. Important findings concerning the effects of ATP on central neurons have been made in the last few years. A fast neurotransmitter role of ATP in rat medial habenula reported by Edwards et al (1992) may be the best example. In rat cultured hippocampal neurons, we have found that ATP evokes postsynaptic currents, and increases the intracellular Ca2+ concentration. In addition, ATP also produces a "long-term potentiation like effect" in these cells. Receptors for ATP are generally divided into two classes: one class is coupled with ion channels and the other class is coupled with GTP-binding proteins. In cultured hippocampal neurons, the GTP-binding protein-coupled receptors are present and promote the inhibition of K+ channels. Although the channel-coupled receptors have not been identified in the hippocampal neurons, these channels have been found in nucleus solitarii and locus coeruleus. Several types of ATP receptors have been cloned very recently. These cloned receptors, combined with molecular biological techniques, will allow great progress in this field.

Inhibition by suramin and reactive blue 2 of GABA and glutamate receptor channels in rat hippocampal neurons

Effects of suramin and reactive blue 2 (RB2), compounds known as antagonists at P2-purinoceptors, on ionic currents mediated through GABA and glutamate receptor channels were investigated in rat hippocampal neurons. Under whole-cell voltage-clamp, suramin (30 to 300 microM) and RB2 (10 to 100 microM) inhibited a current activated by 10 microM GABA in a concentration-dependent manner. Suramin (100 and 300 microM) and RB2 (10 and 30 microM) also inhibited an inward current activated by kainic acid (100 microM), an agonist at non-NMDA type glutamate receptor channels, and an inward current activated by N-methyl-D-aspartate (NMDA; 100 microM), an agonist at NMDA type glutamate receptor channels. The inhibition by suramin or RB2 did not exhibit voltage-dependence between -30 and -90 mV in the case of the GABA- or the kainate-evoked current. In contrast, the inhibition by these compounds of the NMDA-evoked current exhibited voltage-dependence and was enhanced by hyperpolarization. When the concentration of agonists was increased by 5- or 10-fold, the magnitude of the inhibition by suramin of the kainate-evoked current and the magnitude of the inhibition by RB2 of the NMDA-evoked current were attenuated. alpha,beta-Methylene ATP (100 microM) did not affect the GABA-, kainate- or NMDA-activated current. The results suggest that suramin and RB2 inhibit GABA receptor channels and glutamate receptor channels. The blockade of these channels must be taken into account when these compounds are used as pharmacological tools to examine an involvement of P2-purinoceptors, especially in preparations where GABAergic or glutamatergic neurotransmission is expected.

Accentuation by pertussis toxin of the 5-hydroxytryptamine-induced potentiation of ATP-evoked responses in rat pheochromocytoma cells

We previously demonstrated that 5-hydroxytryptamine (5-HT) enhances the cationic current activated by extracellular ATP in rat pheochromocytoma PC12 cells. We report here that pertussis toxin (PTX) modulates this 5-HT-dependent enhancement in these cells. 5-HT potentiated ATP-evoked intracellular Ca2+ concentration ([Ca]i) rise and dopamine release over a concentration range from 1 to 100 microM. When cells were pre-treated with PTX, this potentiation was accentuated. Pretreatment with PTX also accentuated the 5-HT-dependent enhancement of the ATP-activated current. These results suggest that the enhancement by 5-HT of the ATP-evoked responses is negatively regulated by a mechanism mediated through PTX-sensitive GTP-binding protein.

Graves' hyperthyroidism following transient thyrotoxicosis during interferon therapy for chronic hepatitis type C

We report a case of Graves' hyperthyroidism induced by long-term interferon (IFN) therapy. A 52-year-old woman suffered from chronic active hepatitis type C and was treated with a total of 456 x 10(6) units of IFN-alpha for 23 weeks. During the 12th week of treatment she showed transient thyrotoxicosis. One week after the termination of IFN therapy, TSH-receptor antibodies became positive and subsequently she showed Graves' hyperthyroidism. This case showed sequential manifestation from transient thyrotoxicosis to the appearance of TSH-receptor autoantibodies, and then the occurrence of Graves' hyperthyroidism during IFN therapy. The course of this case may be useful in the understanding of the pathogenesis of autoimmune hyperthyroidism.

[Fibroma of the bladder associated with a large diverticulum: a case report]

A 57-year-old woman was admitted with a chief complaint of difficult urination on June 7, 1993. A filling defect and a large diverticulum were revealed on the cystogram. Cystoscopy showed a tumor, obstructing the internal urethral orifice at the bladder neck and a diverticulum at the right posterior wall of the bladder. Under the preoperative diagnosis of a benign bladder tumor with a diverticulum, resection of the tumor and transvesical diverticulectomy were performed by a suprapubic approach. The resected tumor was smooth-surfaced, elastic soft and was measured 2.0 by 1.5 by 1.0 cm in size. Histologically, the tumor was diagnosed as a benign fibroma of the urinary bladder. The postoperative course was uneventful. Non-epithelial benign bladder tumors are rare. To our knowledge, this is the 18th case of bladder fibroma in the Japanese literature. The characteristics of bladder fibroma are briefly described.

Application of three-dimensional spiral computed tomographic angiography prior to hepatectomy for hepatocellular carcinoma

A newly developed method of spiral computed tomography (CT) angiography was employed for 19 consecutive hepatocellular carcinoma (HCC) patients who underwent hepatectomy. Fine images of the intrahepatic vascular structure, portal venous branches and hepatic veins, and HCC nodules were obtained in 16 patients. A more accurate and easier understanding of the relationship between the intrahepatic vascular structure and the HCC nodules was provided by this spiral CT angiography compared with any other imaging modality.

ETB receptor involvement in stimulatory and neurotoxic action of endothelin on dopamine neurones

We examined the role of endothelin (ET) receptor subtypes in mediating the transient and sustained release of dopamine (DA) evoked by ETs and ET-1-induced dopaminergic dysfunction in rat striatal slices. Both phases of the release of DA evoked by ET-1 and ET-3 were inhibited by RES-701-1 (ETB antagonist) but not BQ-123 (ETA antagonist). The high K(+)-evoked DA release from slices remained impaired following a brief exposure to ET-1, under conditions of hypoxia/hypoglycaemia. RES-701-1 but not BQ-123 led to a recovery from ET-1-induced striatal dysfunction. Therefore, ETB receptors are involved in the stimulatory and neurotoxic actions of ETs on the striatal dopaminergic system.

Modulatory effect of plasminogen on NMDA-induced increase in intracellular free calcium concentration in rat cultured hippocampal neurons

The effect of plasminogen on the intracellular Ca2+ concentration ([Ca]i) was examined in cultured rat hippocampal neurons. Plasminogen (100 nM) did not increase [Ca]i in the presence of tetrodotoxin (TTX, 3 microM) but increased [Ca]i in the absence of TTX. In all the cells which responded to plasminogen (100 nM), NMDA (5 microM) also increased [Ca]i in the presence of TTX. Furthermore, plasminogen (100 nM) enhanced the NMDA-evoked [Ca]i increase, and the potentiation by plasminogen was blocked by an NMDA receptor blocker, 2-amino-phosphonovalerate (APV). These data suggest that plasminogen enhances glutamate-evoked [Ca]i increase through modulation of NMDA receptor in hippocampal neurons.

Purification and characterization of a protein that binds to metal responsive elements of the human metallothionein IIA gene

Metal responsive element (MRE) is a cis-acting DNA motif located in the upstream region of vertebrate metallothionein genes, which can confer metal responsiveness on downstream heterologous promoters. A protein that binds to the MRE sequence in a zinc-dependent manner (zinc regulatory factor; ZRF) was purified 16,000-fold from HeLa cell nuclear extracts by means of the avidin-biotin method, in which a complex formed between ZRF and a biotinylated probe containing MRE was trapped by streptavidin-agarose beads, and ZRF was recovered by salt extraction. By repeating the method three times, a homogeneous 116-kDa protein was obtained whose recovery was zinc-dependent and MRE sequence-specific. UV cross-linking analysis also revealed that a protein that specifically binds to MRE has the same molecular mass as the purified protein. Zinc-dependent and MRE sequence-specific footprints of ZRF were obtained on MREa and MREb in the upstream region of the human metallothionein IIA gene. The ZRF-MRE complex dissociates by the addition of chelating reagents, suggesting a direct role of zinc ions in the DNA binding of ZRF. Partial amino acid sequences of ZRF were found to be highly homologous to those of a mouse MRE-binding protein, mMTF-1.

Gastric carcinoma: monoclonal epithelial malignant cells expressing Epstein-Barr virus latent infection protein

In 1000 primary gastric carcinomas, 70 (7.0%) contained Epstein-Barr virus (EBV) genomic sequences detected by PCR and Southern blots. The positive tumors comprised 8 of 9 (89%) undifferentiated lymphoepithelioma-like carcinomas, 27 of 476 (5.7%) poorly differentiated adenocarcinomas, and 35 of 515 (6.8%) moderately to well-differentiated adenocarcinomas. In situ EBV-encoded small RNA 1 hybridization and hematoxylin/eosin staining in adjacent sections showed that the EBV was present in every carcinoma cell but was not significantly present in lymphoid stroma and in normal mucosa. Two-color immunofluorescence and hematoxylin/eosin staining in parallel sections revealed that every keratin-positive epithelial malignant cell expressed EBV-determined nuclear antigen 1 (EBNA1) but did not significantly express CD45+ infiltrating leukocytes. A single fused terminal fragment was detected in each of the EBNA1-expressing tumors, thereby suggesting that the EBV-carrying gastric carcinomas represent clonal proliferation of cells infected with EBV. The carcinoma cells had exclusively EBNA1 but not EBNA2, -3A, -3B, and -3C; leader protein; and latent membrane protein 1 because of methylation. The patients with EBV-carrying gastric carcinoma had elevated serum EBV-specific antibodies. The EBV-specific cellular immunity was not significantly reduced; however, the cytotoxic T-cell target antigens were not expressed. These findings strongly suggest a causal relation between a significant proportion of gastric carcinoma and EBV, and the virus-carrying carcinoma cells may evade immune surveillance.

Inhibitory effects of capsaicin on acetylcholine-evoked responses in rat phaeochromocytoma cells

1. The effects of capsaicin on cellular responses evoked by acetylcholine (ACh) and those by adenosine 5'-triphosphate (ATP) were investigated in rat phaeochromocytoma PC12 cells. 2. Capsaicin (1 to 30 microM) suppressed dopamine release and the intracellular Ca2+ increase evoked by 100 microM ACh. The concentration-dependence of the ACh-evoked release of dopamine was not shifted but the maximal response was reduced by capsaicin. Dopamine release evoked by 80 mM KCl was also suppressed by capsaicin (3 and 30 microM), but the extent of suppression was smaller than that of the ACh-evoked release. 3. Under whole-cell voltage-clamp, capsaicin (1 to 30 microM) reversibly inhibited the inward current activated by ACh (30 to 300 microM). The inhibition exhibited dependence on the concentration of ACh, and the current activated by a higher concentration of ACh was less inhibited. Voltage-dependence of block by capsaicin was not observed when it was tested either by applying a ramp pulse during the current activation by ACh or by eliciting the current in cells held at various potentials. 4. High concentrations of capsaicin (30 to 100 microM) enhanced the inward current as well as dopamine release evoked by 30 microM ATP. 5. The results suggest that low concentrations of capsaicin selectively antagonize responses mediated by nicotinic receptor-channels without affecting those mediated by purinoceptor-coupled channels. As the antagonism by capsaicin of the ACh-evoked responses was observed at concentrations as low as 1 microM, the influence on nicotinic receptors should be taken into account when this compound is used as a pharmacological tool to deplete neuropeptides.

[Toxicity studies of paclitaxel. (II)--One-month intermittent intravenous toxicity in rats]

Paclitaxel, an antineoplastic agent, was intravenously given to Crj:CD (SD) rats of both sexes at 0 (saline), 0 (vehicle), 1.0 (low dose), 3.3 (intermediate dose) and 10.0 (high dose) mg/kg at five-day interval over one-month period (6 times in total) to investigate its repeated dose toxicity and the reversibility of toxic effects. The results obtained are summarized as follows: 1. Decreased activity with prone position was observed for high dose and vehicle groups, and alopecia was seen for many high dose rats. Body weight gain and food intake were suppressed for high and intermediate dose groups. No deaths occurred. 2. Red blood cell count, hemoglobin, hematocrit, white blood cell count, relative neutrophil count, platelet count and reticulocyte count were decreased for high dose groups. Red blood cells count was also decreased for intermediate dose groups. 3. Thymic atrophy, splenic hematopoiesis, bone marrow hypoplasia, testicular atrophy with suppression of spermatogenesis and tubular atrophy, and epididymal atrophy were observed for high dose rats. 4. Above-described changes excluding the findings on the testis and epididymis for high dose rats were shown to be generally reversible. Based on these results, the no-toxic effect dose of paclitaxel was estimated to be 1.0 mg/kg in rats under this study condition.

[Reproductive and developmental toxicity studies of paclitaxel. (I)--Intravenous administration to rats prior to and in the early stages of pregnancy]

Paclitaxel, an antineoplastic agent, was administered intravenously to Crj: CD (SD) rats daily at dose levels of 0 (saline and vehicle), 0.1, 0.3 and 1.0 mg/kg for 63 days prior to mating and during the mating period in males, and for 14 days prior to mating and during the mating period as well as day 0 to day 7 of gestation in females. Results were as follows: 1. Body weight gains were shown a tendency to hasten in vehicle-treated male rats associated with the increased food consumption. However, the vehicle-treated group had no effect in the other parameters that were measured in this study when compared to the saline-treated group. 2. 1.0 mg/kg paclitaxel caused suppression of the body weight gains accompanied by the decreased food consumption in either male or female rats. 3. Adrenal and ovarian weights were decreased in 1.0 mg/kg dams at term. 4. The fertility indices in both sexes of 1.0 mg/kg were lower than the saline-treated group. However, the copulation indices in both sexes in 1.0 mg/kg rats were comparable to those of the saline-treated group. 5. Decreases in the number of corpora lutea, implantations and live fetuses or increases in the number of empty implantation sites and total embryo-fetal deaths were observed in 1.0 mg/kg dams. However, the fetal weights, crown-rump distances and tail lengths in live fetuses were not affected by paclitaxel treatment. Based on the reproductive and developmental indices, the no toxic-effect dose level of paclitaxel is 0.3 mg/kg/day for parent animals and their fetuses.

Assessment of testicular biopsy after cessation of maintenance chemotherapy in childhood acute lymphoblastic leukemia: a report from the Children's Cancer and Leukemia Study Group

Among 484 male patients with acute lymphoblastic leukemia (ALL) registered into the protocols CCLSG 811, 841 and 874, from 1981 through 1990, 246 patients completed their protocols and were in continuous complete remission (CCR) for more than 3 years. One hundred and seven patients received bilateral testicular biopsies at the time of cessation of maintenance chemotherapy. Eight patients (7.5%) were found to have occult testicular leukemia (TL). Three of them did not receive any additional therapy and all suffered subsequent relapses; one bone marrow relapse and two testicular relapses. The other 3 patients received testicular radiation combined with an additional 2 years of chemotherapy, resulting in CCR for more than 6 years 10 months, 7 years 6 months, and 8 years 6 months. One with chemotherapy alone and another with radiation alone showed subsequent relapse. Overt TL after negative initial biopsy was developed in 3 (3.0%) of the 99 patients. All of them received testicular radiation with chemotherapy, resulting again in CCR for more than 1 year 0 months and 5 years 3 months; one patient showed relapse in testes and bone marrow after 3 years 8 months of CCR. These studies suggested that occult TL has an adverse prognostic significance unless retrieval chemotherapy is given and that performance of testicular biopsy at completion of maintenance chemotherapy is not contributory to prolongation of disease-free survival for males with ALL because the treatment employing testicular radiation plus retrieval chemotherapy for both occult TL and isolated overt TL after off-therapy is similarly very effective.

Adrenocorticotropic hormone-independent bilateral adrenocortical macronodular hyperplasia: a case report and immunohistochemical studies

A 55-year-old woman developed Cushing's syndrome due to ACTH-independent bilateral adrenocortical macronodular hyperplasia. Plasma ACTH was undetectable, and was not stimulated by administration of metyrapone, CRH, or insulin. Hypercortisolism was not suppressed by a high dose of dexamethasone, but was responsive to ACTH. Both adrenal glands were enlarged with a total weight of 200 g, and contained multiple nodules composed of two cell types (large clear cells and small compact cells). In immunohistochemical studies, P450c17 immunoreactivity was predominantly observed in small compact cortical cells, while that of 3 beta HSD was observed exclusively in large clear cortical cells. This pattern of expression of steroidogenic enzymes as well as histological and clinical features is considered to be unique to ACTH-independent bilateral adrenocortical macronodular hyperplasia.