Regulation of the concentration of dynorphin A1-8 in the striatonigral pathway by the dopaminergic system

The purpose of this study was to explore the dopaminergic control of the striatonigral dynorphin system by measuring the levels of dynorphin A1-8-like immunoreactivity (DN-LI) after repeated injections of a dopaminergic receptor agonist or antagonist. Seven daily injections of different doses of apomorphine (0.5, 1.0, 2.5 and 5.0 mg/kg, s.c.) caused a significant dose-related increase of DN-LI in the striatum (26, 34, 63, 85% over control at each corresponding dose). Similar increases were observed in the substantia nigra (22, 52, 50 and 62% over control). In another experiment, rats received 5 mg/kg of apomorphine for 1, 3, and 7 days. There was a significant time-related increase in DN-LI both in the striatum (37, 50 and 85% over control at each corresponding period) and in the substantial nigra (32, 78 and 62%). Repeated administration of haloperidol (1 mg/kg, i.p.) failed to change the striatal level of DN-LI, but, when given at the same time as apomorphine, significantly attenuated the effect of apomorphine. These results suggest that dopamine exerts a modulatory influence on the metabolism of dynorphin in the striatonigral pathway.

The role of dopamine in the control of neuropeptide Y neurons in the rat arcuate nucleus

In order to determine the role of dopamine (DA) on neuropeptide Y (NPY) neurons in the arcuate nucleus of the rat hypothalamus, we evaluated the effects of alpha-methylparatyrosine (alpha-MPT), an inhibitor of catecholamines biosynthesis, and haloperidol, a dopaminergic antagonist, on NPY immunoreactive neurons. The two drugs used produced in the arcuate nucleus the appearance of a large number of NPY-containing neuronal bodies which are normally absent in control animals. The density of stained fibers were not significantly modified. These results suggest that DA can exert some negative regulation of NPY neurons activity in the arcuate nucleus.

Effect of azimexon therapy on host defense parameters and disease-associated symptoms in the acquired immune deficiency syndrome (AIDS) and AIDS-related complex (ARC)

Azimexon, a 2-cyan-aziridinyl immune modulator, was given at a dose of 250 mg/m2/day for 10 days IV to 12 patients with AIDS and 16 with AIDS related complex (ARC). A decrease in total number of AIDS related symptoms from 43 to 24 and in mean number from 2.6 to 1.5 was observed among ARC patients (p less than .01). The most commonly improved symptoms were diarrhea, fatigue, and weight loss with the least frequently improved being lymphadenopathy. The following improvements in immune parameters were observed among ARC patients. DTH to recall antigens improved with an increase in number of positive tests from 35 to 47 and in mean number of positive skin tests from 2.2 on day 0 to 2.9 on day 14 (P less than .05). The geometric mean of the absolute lymphocyte count was 1.395 X 10(3)/microliter on day 0 with a significant increase of 18.0 percent on day 5 (P less than .01) and a 7.7 percent increase on day 21. The geometric mean of the OKT4+ cells on day 0 was 0.250 X 10(3)/microliter with a 33.3 percent increase on day 5 (P less than .07) and a 14.1 percent increase on day 21. T4/T8 ratio increased by 32.7 percent on day 5 (P less than .05) and by 19.4 percent on day 21 from an initial geometric mean of 0.339 X 10(3)/microliter on day 0. The geometric mean of GVH responses increased by 18.2 percent on day 5 (P less than .05) and by 24.0 percent on day 21 (P less than .07) from an initial value of 41.04 mm3. No symptomatic or immunologic improvements were observed among AIDS patients, but rather a significant decrease in mitogenic responses. PHA responses decreased by 70.3 percent on day 5 (P less than .05) and 42.2 percent on day 21 from an initial geometric mean of 4.02 X 10(3) cpm/10(3). Con-A responses decreased by 75.1 percent on day 5 (P less than .05) and increased by 20.3 percent on day 21 from an initial value of 1.14 X 10(3)/10(5) cells. Pretreatment number of absolute OKT4+ cells was the most significant prognostic survival variable. Thus, 8/9 patients with less than 0.10 X 10(3) OKT4+ blood cell/microliter subsequently died as compared to only 1/17 with greater than or equal to 0.10 X 10(3) OKT4+ cells (p less than .001). The only toxic effect of this treatment was mild hemolysis which disappeared upon cessation of treatment.(ABSTRACT TRUNCATED AT 400 WORDS)

Delineation of two distinct regulatory domains in the 5' region of the nar operon of Escherichia coli

A detailed restriction site map was determined for an 8.4-kilobase DNA fragment containing the 5' regulatory and promoter region of the nar operon of Escherichia coli. The 5' end of the nar operon was subcloned as a 2.5-kilobase fragment, and an intact nar operon was constructed from this subcloned fragment and an EcoRI fragment containing the remainder of the nar operon. A set of Bal 31 deletions extending into the 5' region of the intact operon was selected, mapped, and characterized. Based on the synthesis of the alpha and beta subunits of nitrate reductase in a nar::Tn5 mutant, three categories of deletions were found: (i) those which permitted normal expression, (ii) those which completely prevented expression, and (iii) those which permitted anaerobic expression of the operon but prevented any additional induction by nitrate. The nucleotide sequence was determined for a segment of the nar promoter region starting at one of the latter deletion end points and extending into the first structural gene of the operon. The position of the deletion end point relative to the translation start site for the first structural gene, narG, was defined by identifying the nucleotide sequence for the first 20 N-terminal amino acid residues of the alpha subunit of nitrate reductase. Deletions terminating 161 base pairs (bp) and approximately 200 bp upstream from the narG translation start site permitted anaerobic formation of nitrate reductase but interfered with the stimulation of nar operon expression by nitrate. A maximum size for the regulatory region was defined by two Tn5 insertions, which mapped approximately 550 bp 5' from the translation start site and did not interfere with the normal expression of nitrate reductase under anaerobic conditions with or without nitrate. We conclude that the nar operon 5' regulatory region is divided into two distinct regions: the 100 to 150 bp immediately 5' to the narG gene include a transcriptional start site and the signals necessary for anaerobic expression of the operon, and an adjacent region of 50 to 400 bp is required for the stimulation of operon expression by nitrate.

Abnormalities of myeloid progenitor cells after "successful" bone marrow transplantation

We studied recovery of peripheral blood- and bone marrow-derived myeloid progenitor cells (CFU-G,M) in 29 patients who received bone marrow transplants 2 mo to 8.5 yr previously. All patients had normal levels of peripheral blood neutrophils, normal bone marrow cellularity, and a normal myeloid-erythroid ratio. Both peripheral blood- and bone marrow-derived CFU-G,M were markedly reduced compared with normal controls and bone marrow donors [5 +/- 1/10(6) vs. 37 +/- 4/10(6) (P less than 0.001) and 23 +/- 5/2 x 10(5) vs. 170 +/- 21/2 x 10(5) (P less than 0.001)]. Five patients had no detectable CFU-G,M even when 10(6) bone marrow cels were plated. These abnormalities of CFU-G,M were unrelated to age, sex, diagnosis, conditioning regimen, dose of bone marrow cells transplanted, and presence or absence of graft-vs.-host disease. Patients who received either autotransplants or transplants from identical twins also had decreased or absent CFU-G,M indicating that allogeneic factors and posttransplant immune suppressor with methotrexate or corticosteroids were not major determinants of this abnormality. Co-culture of normal or donor peripheral blood or bone marrow mononuclear cells with recipients peripheral blood or bone marrow mononuclear cells, purified T cells, or serum failed to show any evidence of active CFU-G,M suppression. Furthermore, the abnormality of CFU-G,M could not be corrected by the addition of normal syngeneic (donor) hematopoietic cells or serum. Depletion of T-cells from recipient bone marrow by physical techniques resulted in marked increase in CFU-G,M (36 +/- 13 vs. 138 +/- 36; P less than 0.05). The abnormality could be reproduced in vitro by readdition of autologous T cells. In contrast to results with T cell depletion by physical techniques, T cell depletion with a monoclonal anti-T antibody (B7) and complement had no effect. These data indicate that most-transplant recipients have a marked abnormality in CFU-G,M when these cells are cultured in vitro. In at least some of these patients, the decreased cloning efficiency of CFU-G,M appears to be mediated by a suppressive effect of autologous T cells.

Current status of activity assays for tissue plasminogen activator

Tissue plasminogen activator (TPA) is a serine protease involved in the fibrinolytic system that dissolves blood clots. The enzyme catalyzes the conversion of a zymogen, plasminogen, to the enzymatically active form, plasmin, by limited proteolysis. In the course of searching for specific activity assays that might be useful in monitoring the purification of TPA, we have developed several coupled photometric assays. In addition, radioactive, agarose-plate, and other activity assays have also been considered and investigated for this purpose (Table 1). We have previously reported the one-step photometric procedure consisting of a thioester, thiobenzyl benzyloxycarbonyl-lysine (Z-Lys-S-Bzl) and fibrinogen-coated plates. It is simpler and more sensitive than the old two-step method without using immobilized fibrinogen. The new assay has been used successfully for protein purification and can be easily adapted to automated processes. Recently, other chromogenic substrates, D-Val-L-Leu-L-Lys-p-nitroanilide (Val-Leu-Lys-pNA) and D-Ile-L-Pro-L-Arg-p-nitroanilide (Ile-Pro-Arg-pNA) were also used in the one-step assay. It is found that TPA activity is greatly enhanced by immobilized fibrinogen and free fibrinogen when either the thioester. Val-Leu-Lys-pNA, or Ile-Pro-Arg-pNA were used in the colorimetric assay (Fig. 1, A-D). Enzyme kinetics studies indicate that the Km for plasminogen assayed on the thioester and fibrinogen-coated plates is 1.5 micrograms per ml, which is substantially lower than that observed in untreated plates (4.8 micrograms per ml). This is not due to the effect of fibrinogen on the second step of the coupled photometric assay because there is no change in the plasmin activity under these conditions (Fig. 1E). Similar results in TPA activation have also been observed, when fibrin-coated plates were used. Free fibrinogen, which is an activator of TPA, has been included in the standard assay mixture. We are able to detect less than 1 ng of TPA activity within a one-hour incubation time at 20 degrees C (Fig. 2A). In the thioester assay, however, high concentrations of reducing agents and nonspecific proteins cause significant background due to the interaction of DTNB with these reagents. 125I-labeled fibrin-coated plates had been extensively used in the past for urokinase and TPA assays. Although the sensitivity of the radioactive procedure is equivalent to that of the thioester photometric method, it appears that the kinetics of the enzyme are not easy to follow nor is the reproducibility great.(ABSTRACT TRUNCATED AT 400 WORDS)

Plasma methionine-enkephalin and leucine-enkephalin in normal subjects and patients with pheochromocytoma

Plasma methionine-enkephalin-like and leucine-enkephalin-like immunoreactivity (met-enkephalin-LI and leu-enkephalin-LI, respectively) in six normal subjects and six patients with pheochromocytoma were determined. The contents of met-enkephalin-LI and leu-enkephalin-LI in two of six pheochromocytomas were 40- to 50-fold higher and those in the other four pheochromocytomas were less than those in normal human adrenal medulla. The former two patients showed high plasma met-enkephalin-LI and leu-enkephalin-LI levels. As plasma catecholamines levels returned to the normal range after extirpation of tumors, met-enkephalin-LI and leu-enkephalin-LI in plasma became undetectable in these patients. In contrast, neither met-enkephalin-LI nor leu-enkephalin-LI was detected in plasma from the latter four patients. Met-enkephalin-LI and leu-enkephalin-LI concentrations were higher in the adrenal vein than in the peripheral vein in three patients. Plasma met-enkephalin-LI and leu-enkephalin-LI increased concomitantly with catecholamines after glucagon stimulation and during a spontaneous attack in a patient with pheochromocytoma. Plasma met-enkephalin-LI changed in parallel with leu-enkephalin-LI in all cases. High performance liquid chromatography coupled with RIAs has shown that met-enkephalin and leu-enkephalin circulate in plasma from a patient with pheochromocytoma as intact pentapeptides. None of normal subjects showed detectable concentrations of met-enkephalin-LI and leu-enkephalin-LI in plasma (more than 5 pg/ml and 3 pg/ml, respectively). It is concluded that met-enkephalin and leu-enkephalin are released concomitantly with catecholamines from pheochromocytomas.

Reducing attrition from conjoint therapy with alcoholic couples

Premature termination of treatment by the client has been a pervasive problem in the alcohol treatment field. This drop-out problem is compounded in conjoint therapy for alcoholic couples since most clients typically do not view the drinking problem from a systemic, interactional perspective. Within a short-term communication-interaction based conjoint therapy program offered to couples with an alcohol problem on an outpatient basis, specific mechanisms were developed to deal with client-initiated attrition from treatment. These procedures involve the systematic involvement of the spouse in all aspects of intake, assessment and treatment; the use of role induction in a pretherapy interview; and formal contracting during the beginning phase of therapy. Preliminary results suggest that these efforts may be effective in retaining more socially stable alcoholic clients. For the more transient, less socially stable group of individuals with alcohol-related difficulties, the above mechanisms may not be sufficient to forestall unplanned terminations. It is suggested that the latter group may require help to reduce stresses related to concrete concerns prior to receiving conjoint therapy for their alcohol problem.

Karyological analysis of N-methyl-N'-nitro-N-nitrosoguanidine-transformed Syrian hamster cell lines using high resolution G-banding technique

The karyotypes of two Syrian hamster cell lines transformed by N-methyl-N'-nitro-N-nitrosoguanidine have been analyzed using high resolution G-banding technique. The change of gene dosage appears to be the main feature of the chromosome aberrations. One of the cell lines (BHLB4) has been passaged in vitro for 68 times and has a pseudodiploid chromosome number of 44. The most common feature of aberrations of this cell line is monosomy of chromosome 15 and in addition trisomy of chromosome 8. The other cell line (HEC5) was newly transformed, having a modal chromosome number of 50. In spite of the occurrence of trisomy of some autosomes, monosomy of chromosome 15 was still evident. No obvious structural changes were found even in G-banded prophase chromosomes. Our observations support the previous report on the monosomy of chromosome 15, as the most common feature of virally- and chemically-transformed Syrian hamster cell lines.

Isolation and preliminary characterization of the synaptonemal complex from rat pachytene spermatocytes

A method for preparation of the morphologically intact synaptonemal complex from rat pachytene spermatocytes is described. Pachytene spermatocytes were fractionated from rat testicular cells by centrifugal elutriation. Nuclei from fractionated pachytene cells were prepared and extensively digested with micrococcal nuclease. The digested nuclei were sedimented through 20% (w/v) sucrose containing 2 M NaCl by centrifugation. About 10% of total nuclear proteins and 1-2% of total genomic DNA was found to be associated with the residual structure. The residual structure, which contains mainly the synaptonemal complex, but may be still contaminated with other nuclear components including membrane and matrix, was stained with silver and examined under light microscopy. It was found that a silver-staining component of the synaptonemal complex is not grossly different from that in pachytene nuclei not subjected to digestion and extraction. Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis revealed that virtually all the proteins in the residual structure are non-histones. The DNA isolated from the residual structure was about 135 base pairs (bp), long. The DNA was end-labeled and hybridized with a large excess of sonicated rat genomic DNA. The hybridization displayed a kinetics virtually identical to that of total nuclear DNA. We also prepared restricted DNA fragments associated with the residual structure. Southern blot analyses using a probe made from a recombinant DNA clone containing the albumin gene revealed that the DNA associated with the residual structure was not enriched (or depleted) in this gene sequence. Our results strongly suggest that (1) the synaptomenal complex may play a structural role to support the chromatin domains inside pachytene nucleus; and (2) a simple common DNA sequence in the chromatin domain is not required for association with the residual structure which contains morphologically intact synaptonemal complex in rat spermatocytes.

Baseline and mitomycin-C-induced sister chromatic exchanges ina melanoma and a colon tumor cell line

Baseline and mitomycin C (MMC)-induced sister chromatid exchanges (SCEs) in two human tumor cell lines (a colon tumor and a melanoma) and in a normal fibroblast cell line were analyzed and compared. The tumor cells showed numerical and structural chromosomal abnormalities. Their baseline SCE rate was slightly, but not significantly, higher than that of the control. Each tumor cell line showed a dose-dependent increase in SCE frequency above the spontaneous level in its own specific manner. The response in the malanoma cell was consistently below that of the control, but only the response to the highest dose of MMC (10(-9) M) was significantly lower than that of the control. The response of the colon tumor cells varied with respect to that of the control. Thus, it appears that karyotypic instability in tumor cells is not necessarily associated with elevated baseline or induced SCE/chromosome rates. In addition, within each cell line dose group, the SCE frequency was proportional to the number of chromosomes. thus, the SCE/chromosome is a better expression of genetic damage than SCE/metaphase in analyses involving heteroploid cells.