Prolactin release induced by opiate agonists, effect of glucocorticoid pretreatment in intact and adrenalectomized rats

Cortisol administered at a dose of 25 mg/kg 24 h before measurements decreased the prolactin secretion induced by intraventricularly given opioids (dynorphin, beta-endorphin, Met-enkephalin or D-Met-Pro-enkephalinamide). The effect of cortisol was depressed by actinomycin D pretreatment. The cortisol-induced inhibition of the action of morphine was facilitated in adrenalectomized animals; measuring the effects of increasing doses of cortisol a maximal inhibition was obtained at a dose of 5 mg/kg. The opioid-induced corticosterone secretion was not affected 24 h after a single administration of cortisol. The present results show that the cortisol-induced inhibition of opioid-induced prolactin secretion is dependent on protein synthesis and independent of changes in drug metabolism, and of the type of opiate receptor preferentially affected by the opiate agonists employed.     

Circannual variation in lymphocyte subsets, revisited

BACKGROUND: Circadian and circannual variations in lymphocyte subsets, especially CD8+ T-lymphocytes, have been reported. This study focuses on CD4+ T-lymphocyte seasonal variation over a 6-year 8-month period. STUDY DESIGN AND METHODS: Lymphocyte subsets were quantitated monthly for four healthy individuals from 1986 through 1992 as part of a flow cytometry quality-control program. RESULTS: In general, there were no significant seasonal changes in the total number of white cells or in total lymphocyte counts. The absolute numbers of CD4+ T-lymphocytes were lowest in summer when the CD8+ T-lymphocytes were highest. Mean CD4+ T-lymphocyte counts were 846, 967, 618, and 695 per microL for Subjects 1 through 4, respectively, in winter and 432, 670, 355, and 766 per microL, respectively, in summer. Two healthy subjects had CD4+ T-lymphocyte counts lower than 300 per microL on one or more occasions during the study period. In three of the four subjects, the percentage of B-lymphocytes in winter was almost double that in summer. In one of the four subjects, no circannual rhythm was observed in these lymphocyte subpopulations. CONCLUSION: The seasonal variation in CD4+ T- lymphocyte counts demonstrated in three healthy individuals over almost 7 years is again of interest in light of renewed consideration of using surrogate tests, such as CD4+ T-lymphocyte counts, to screen for AIDS- like diseases that may be in the blood supply.     

The family history in family practice: a questionnaire study

OBJECTIVES: Our aims were to investigate family medical history taking in general practice, and to evaluate the value attached to the family medical history as an aid to decision making in general practice. METHOD: A postal questionnaire survey was conducted among all 291 GPs working within the Calderdale and Kirklees Health Authority area. Each questionnaire was followed by a reminder. The main outcome measures were answers to questions on routine and opportunistic family history taking and a question about transmitting knowledge about genetic risk to other members of the family. Questions were also posed about the value attached to the family medical history as an aid to decision making. RESULTS: A total of 193 GPs returned the questionnaire (response rate 66.3%). On registration, 94.3% of GPs indicated that enquiries were made about a family history of coronary heart disease. Breast and colorectal cancer were specifically asked about by 48.4% and 30.7% of GPs, respectively. One-fifth of respondents indicated that they asked a general question about family medical history. A little over one-quarter of respondents indicated that they made opportunistic enquiries about the family history or suggested that the patient should inform other members of the family about possible risks. In the scenarios highlighted in this study, the majority of respondents felt that the family medical history had value as an aid to decision making. This was particularly the case for checking a patient's cholesterol (92.1%) and for initiating referrals in younger patients with possible cancer-related symptoms (three-quarters of respondents). CONCLUSION: GPs value the family medical history as an aid to decision making. Unfortunately, apart from enquiries about coronary heart disease, routine or opportunistic family history taking is not occurring in practice. Mechanisms need to be sought to extract information from the family medical history so that it can be more effectively used by GPs.      

Greater sensitivity of pigtailed macaques (Macaca nemestrina) than baboons to total body irradiation

Two juvenile pigtailed macaques (animals 1 and 2) received total body irradiation (TBI) followed by autologous stem cell transplantation, by a procedure known to be well tolerated by baboons. In this procedure, the TBI consisted of treatment on two consecutive days with 255cGy on one side, followed after 1-2 min by a similar dose on the other side. The two pigtailed macaques showed rapid haematopoietic engraftment, but succumbed either to systemic cytomegalovirus (CMV) infection and necrotising colitis or to haemorrhagic cystitis and tubulointerstitial nephritis. For four further pigtailed macaques (animals 3-6) the radiation procedure was changed to four equal doses of 255cGy, given 6-12 h apart. Animals 4-6 all showed engraftment and survived for long periods (>218 days), with no, or only minor treatable, complications. Animal 3 failed to show engraftment and succumbed to radiation-induced vascular lesions and severe multiorgan haemorrhages. The results suggest that pigtailed macaques have a lower tolerance threshold than baboons, rhesus macaques or human beings to TBI, the adverse effects of TBI being indistinguishable from those seen in human patients. The results also suggest that a hyperfractionated radiation procedure can prevent radiation-induced morbidity and mortality in pigtailed macaques.     

Three new steroidal saponins from Aspidistra letreae plants and their cytotoxic activities

Three new steroidal saponins, aspiletreins A–C (1–3), together with 2H-chromen-2-one (4), and α-tocopherol (5), were isolated from whole Aspidistra letreae plants collected in Vietnam. Their structures were elucidated by a combination of spectroscopic analyses, including 1D- and 2D-NMR, IR, and HRESIMS, and by comparison with the reported data in the literature. Compounds 1–3 exhibited moderate cytotoxicities against the LU-1, HeLa, MDA-MB-231, HepG2, and MKN-7 human cancer cell lines, with IC₅₀ values ranging from 7.69?±?0.40 to 20.46?±?3.11 µM.

     

Scaffold attachment region-containing retrovirus vectors improve long-term proviral expression after transplantation of GFP-modified CD34+ baboon repopulating cells

Sustained high-level proviral expression is important for clinical applications of gene therapy. Genetic elements including the beta-interferon scaffold attachment region (SAR) have been shown to improve transgene expression in hematopoietic cells. We hypothesized that SAR elements might improve expression and allow the preselection of successfully transduced cells. Thus, we transplanted green fluorescent protein (GFP)-selected cells, half of which had been transduced with either SAR or non-SAR-containing retrovirus vectors, into 3 animals. All animals showed delayed engraftment compared with historic controls (28 vs 15.5 days). GFP marking was seen at levels up to 8% but declined over the first 6 weeks. Importantly, fluorescence intensity was 2- to 9-fold increased in progeny of SAR versus non-SAR vector-modified cells in all hematopoietic lineages for the duration of follow-up (6-12 months). In conclusion, the use of SAR-containing vectors improved transgene expression in hematopoietic repopulating cells, which may obviate the need for multicopy integration to achieve high-level expression and reduce the risk for insertional mutagenesis.     

Antiarrhythmic drug therapy in survivors of prehospital cardiac arrest: comparison of effects on chronic ventricular arrhythmias and recurrent cardiac arrest.

We studied the long-term effects of membrane-active antiarrhythmic agents on chronic ventricular arrhythmias in patients who have survived prehospital cardiac arrest. Among 16 patients treated with a dose-adjusted, plasma level-monitored antiarrhythmic regimen, eight have survived for longer than 12 months and eight have had recurrent cardiac arrests (RCAs). Monthly Holter monitor tapes (HM) recorded during the 4 months before the eight RCAs were compared with monthly HM tapes matched for time of entry and duration of follow-up in the eight patients who did not have RCAs. Transient or persistent complex ventricular ectopic depolarizations (VEDs) have been recorded on 47 of the 63 monthly HM tapes (75%). The difference between VEDs in the RCA patients (mean 153 VEDs/hr, median 19 VEDs/hr) and VEDs in the patients who have not had RCA (mean 122 VEDs/hr, median 8 VEDs/hr) was not significant (p less than 0.2); nor was there a predictable relationship between therapeutic plasma levels of antiarrhythmic agents and the frequency and complexity of chronic asymptomatic VEDs (therapeutic levels--mean 104 VEDs/hr, median 6 VEDs/hr; subtherapeutic levels--mean 184 VEDs/hr, median 21 VEDs/hr). Differences were not significant (p greater than 0.1). In contrast, all eight RCA patients had unstable plasma levels (21 of 31 determinations subtherapeutic) while six of the eight patients who have not had RCA had consistently therapeutic levels (p less than 0.01). Thus, adequate plasma levels of antiarrhythmic agents may protect against RCA, despite failure to suppress VEDs predictably. The apparent dissociation between predictable suppression of chronic VEDs and protection against RCA suggests that clinical effectiveness of these agents may not be best measured by their effect on chronic VEDs.     

Increased gene transfer into human hematopoietic progenitor cells by extended in vitro exposure to a pseudotyped retroviral vector

Retroviral-mediated gene transfer is the most attractive modality for gene transfer into hematopoietic stem cells. However, transduction efficiency has been low using amphotropic Moloney murine leukemia virus (MoMLV) vectors. In this study, we investigated modifications of gene transfer using amphotropic MoMLV vectors in cell-free supernatant for their ability to increase the currently low transduction of both committed hematopoietic progenitors, granulocyte-macrophage colony- forming units (CFU-GMs), and their precursors, long-term culture- initiating cells (LTC-IC). First, based on the observation that bone marrow cells express more gibbon ape leukemia virus (GALV) receptor (Glvr-1) than amphotropic receptor (Ram-1), PG13/LN, which is a MoMLV vector pseudotyped with the GALV envelope, was compared with the analogous amphotropic envelope vector (PA317/LN). Second, progenitor cell transduction efficiency was compared between CD34 enriched and nonenriched progenitor populations. Third, the duration of transduction in vitro was extended to increase the proportion of progenitor cells that entered cell cycle and could thereby integrate vector cDNA. In 20 experiments, 1 x 10(6) marrow or peripheral blood mononuclear cells (PBMCs)/mL were exposed to identical titers of pseudotyped PG13/LN vector or PA317/LN vector in the presence of recombinant human interleukin-1 (IL-1), IL-3, IL-6, and stem cell factor (SCF; c-kit ligand) for 5 days. 50% of fresh vector supernatant was refed daily. Hematopoietic progenitor cells as measured by G418-resistant granulomonocytic colony (CFU-GM) formation were transduced more effectively with PG13/LN (19.35%) than with PA317/LN (11.5%, P = .012). In 11 further experiments, enrichment of CD34 antigen positive cells significantly improved gene transfer from 13.9% G418-resistant CFU-GM in nonenriched to 24.9% in CD34-enriched progenitor cells (P < .01). To analyze gene transfer after extended growth factor-supported long-term culture, 1 x 10(6) marrow cells/mL were cultured with IL-1, IL-3, IL-6, and SCF (50 ng/mL each) for 1, 2, and 3 weeks. Fifty percent of PG13/LN supernatant with growth factors was refed on 5 days per week. Five percent of marrow CFU-GM and 67% of LTC-IC were G418 resistant at 1 week (n = 4), 60% of CFU-GM and 100% of LTC-IC were resistant at 2 weeks (n = 2) and 74% of CFU-GM (n = 4) and 82% of LTC-IC (n = 2) were resistant at three weeks.(ABSTRACT TRUNCATED AT 400 WORDS)