Chronic ethanol effects on the expression of phospholipase C isozymes and Gq/11-protein in primary cultures of astrocytes

The goal of this investigation was to determine whether chronic ethanol exposure alters the expression of specific protein sites distal to receptors [Gq/11-protein, phospholipase C (PLC) isozymes] in primary cultures of astrocytes obtained from neonatal rat cortex. The protein expression (immunolabeling) of the PLC-beta 1, -gamma 1, -delta 1 isozymes and of the Gq/11 alpha subunit was determined by Western blot analysis using specific monoclonal antibodies. The PLC-beta 1, -gamma 1, -delta 1 isozymes and the Gq/11 alpha subunit migrated at apparent molecular masses (PLC-beta 1, 41 kDa; PLC-gamma 1, 145 kDa. PLC-delta 1, 85 kDa: Gq/11 alpha protein, 42 kDa). Thus, a PLC-beta 1 fragment of 41 kDa, but not the biologically active 150 kDa PLC-beta 1, was detected in primary cultures of astrocytes. Chronic ethanol exposure (4 days) resulted in a significant increase in the expression of PLC-delta 1, whereas under identical conditions, the expression of PLC-beta 1, -gamma 1, and of the alpha subunit of Gq/11 protein was not significantly altered in astrocytes. These results suggest that chronic ethanol exposure results in an increased expression of the PLC-delta 1, isozyme in primary cultures of astrocytes.

Dual regulation of open-complex formation and promoter clearance by Arc explains a novel repressor to activator switch

In studies of variants of the P(ant) promoter of bacteriophage P22, the Arc protein was found not only to slow the rate at which RNA polymerase forms open complexes but also to accelerate the rate at which the enzyme clears the promoter. These dual activities permit Arc, bound at a single operator subsite, to act as an activator or as a repressor of different promoter variants. For example, Arc activates a P(ant) variant for which promoter clearance is rate limiting in the presence and absence of Arc but represses a closely related variant for which open-complex formation becomes rate limiting in the presence of Arc. The acceleration of promoter clearance by Arc requires occupancy of the operator subsite proximal to the -35 region and is diminished when Arc bears a mutation in Arg-23, a residue that makes a DNA-backbone contact in the operator complex.

Long-term follow-up of patients with complete remission following combination chemotherapy for metastatic breast cancer

PURPOSE

To determine the long-term clinical course of patients with metastatic breast cancer (MBC) who achieved a complete remission with doxorubicin-alkylating agent-containing combination chemotherapy programs.

PATIENTS AND METHODS

To assess the long-term prognosis of MBC, we reviewed our experience with 1,581 patients treated on consecutive doxorubicin and alkylating agent-containing front-line treatment protocols between 1973 and 1982. Treatment was administered for a maximum duration of 2 years. Characteristics of long-term survivors were evaluated, and hazard rates for progression were calculated.

RESULTS

From this group, 263 (16.6%) achieved complete responses (CR) and 49 (3.1%) remained in CR for more than 5 years. After a median duration of 191 months, 26 patients remain in first CR, four patients died in CR at times ranging from 118 to 234 months, 18 patients died of breast cancer, and one is alive with metastatic disease. Compared with the overall CR and total patient populations, the long-term CR group had more premenopausal patients, a younger median age, a lower tumor burden, and better performance status. The hazard function shows a substantial drop in risk of progression after approximately 3 years from initiation of therapy. Ten long-term CR patients developed second primary cancers: breast (3), ovary (2), pancreas (1), endometrium (1), colon (1), head and neck (1), and lung (1).

CONCLUSION

Most patients with MBC treated with systemic therapies have only temporary responses to treatment, but some patients continue in CR following initial treatment. These data show that a small percentage of patients achieve long-term remissions with standard chemotherapy regimens. Remission consolidation strategies are needed.

Cholestane-3 beta, 5 alpha, 6 beta-triol stimulates phospholipid synthesis and CTP-phosphocholine cytidyltransferase in cultured LLC-PK cells

The present study was conducted to examine the effect, if any, of triol on the rate of total or individual phospholipid synthesis by LLC-PK cells in culture. LLC-PK cells were incubated in medium with or without 10 micrograms/ml of 5 alpha-cholestane-3 beta, 5 alpha,6 beta-triol (triol) for 24 h. Triol-treated and control cells were then incubated with medium containing either [14C]glycerol or [32P]phosphate for 1, 6 or 12 hr. In triol-treated cells, the amount of labeled glycerol and [32P]phosphate incorporated into glycerophospholipids and phospholipids (PL), respectively, were higher in triol-treated cells than in control cells, indicating a higher rate of PL synthesis in triol-treated cells. The results also showed that the increase in PL synthesis was higher in magnitude for some PL than others, thus disturbing the ratios among the PL fractions in the cell membrane. CTP-phosphocholine cytidyltransferase activity was greatly enhanced in the cytosolic as well as the particulate fractions of the triol-treated cells, which explains the increase of PC synthesis under triol effect. The rate of [3H]acetate incorporation into the total and free fatty acid fractions was significantly increased in triol-treated cells. The activation of the cytidyl transferase enzyme was related to the enhanced de novo synthesis and cellular uptake of fatty acids in triol-treated cells, which make fatty acids more available in these cells and can upregulate the enzyme. The increased synthesis of phospholipids in the triol cells and the increased level of phospholipid in these cells (as micrograms lipid phosphorus/mg cell protein) observed in our previous study indicate changes in the phospholipid head group composition of the triol cells. These changes can affect several membrane properties and membrane bound enzymes.

Effect of magnesium on secretion of platelet-derived growth factor by cultured human arterial smooth muscle cells

Two conditioned media were prepared by culturing human umbilical artery smooth muscle cells (SMC) in 75 cm2 flasks with minimum essential medium (MEM) under magnesium (Mg) sufficient (900 microM) or deficient (100 microM) conditions for 72 h ([900]- and [100]-MEM), respectively. A third conditioned medium was obtained by adjusting the Mg concentration of half of the [100]-MEM to 900 microM ([100-900]-MEM). SMC in 12-well plates were incubated in one of the three conditioned media and the growth rates of SMC were determined by [3H]-thymidine incorporation and cell counting. The growth rate in [100-900]-MEM was significantly higher than in [900]- and [100]-MEM. When platelet derived growth factor (PDGF) was neutralized by the addition of a mixture of anti-PDGF-AA and -BB antibodies, [3H]-thymidine incorporation in [100-900]-MEM decreased by 23.3 per cent, but only by 7.0 per cent in [900]-MEM. The quantity of PDGF in the Mg-deficient media was greater than in the magnesium-sufficient media at all indicated times, as shown by radioimmunoassay for PDGF-BB or -AB. These results indicate that Mg deficiency increases the secretion of PDGF by SMC.

Factors predicting complete remission and subsequent disease-free survival after a second course of induction therapy in patients with acute myelogenous leukemia resistant to the first

Patients with newly diagnosed acute myelogenous leukemia (AML) with persistent leukemia after their first course (CO1) of induction chemotherapy are generally given a second similar course, although their outcome is known to be worse than CO1 responders even when a complete remission (CR) is achieved. To identify specific patients who should or should not receive a second induction course identical to the first we analyzed outcome in 370 patients with persistent AML after CO1 who received a second identical course. One hundred and forty-two (38%) achieved CR on this course; median subsequent disease-free survival (DFS) in these 142 was 29 weeks and 10% were alive in CR at 5 years. The 5-year DFS of CO2 responders was significantly lower than that of CO1 responders (10 vs 24%, P < 0.001). Logistic regression identified pretreatment cytogenetic abnormalities (except inv 16, t(8;21), or t(15;17)), presence of an antecedent hematologic disorder or secondary AML as each having unfavorable prognostic import similar to the case in untreated patients. Treatment with "high-dose' rather than standard-dose cytarabine increased the probability of 2nd course CR. The occurrence of pneumonia, sepsis, or major hemorrhage were prognostically unfavorable, primarily in the high-dose cytarabine group, and, once in CR, DFS was shorter in this group. Equations predicting probability of 2nd course CR were derived. If validated prospectively these could be used to assign patients to either receive a second course of initial induction therapy or to change to salvage or investigational therapy after the first course. Alternatively, they could be used to stratify patients entering a prospective randomized trial comparing these two strategies.

Does expression of different EWS chimeric transcripts define clinically distinct risk groups of Ewing tumor patients?

PURPOSE

Because of the high heterogeneity of EWS gene fusions with FLI1 and ERG genes due to variable chromosomal breakpoint locations in Ewing tumors (ET) (14 different chimeric transcripts identified so far), we evaluated the clinical impact of the expression of diverse fusion transcripts in ET patients.

PATIENTS AND METHODS

In a European multicenter study, 147 ET were analyzed by reverse-transcriptase polymerase chain reaction (RT-PCR) and the molecular data statistically compared with all clinical data available.

RESULTS

Most tumors expressed chimeric transcripts with fusion of EWS exon 7 to FLI1 exon 6 (75 of 147) (type I) or five (39 of 147) and EWS exon 10 to FLI1 exon 5 (eight of 147) or 6 (five of 147). In five cases, chimerism between EWS exon 9 and FLI1 exons 4 and EWS exon 7 and FLI1 exon 7 or 8 was observed. Fifteen cases of EWS-ERG rearrangement were identified. In 85 of these patients treated in the European Cooperative Ewing Sarcoma Studies, molecular results were analyzed in comparison to age, sex, tumor localization, tumor volume, and disease extension. No significant correlation between the various fusion types and these features were observed. Relapse-free survival (RFS) for the 31 patients with localized disease and fusion type I tended to be longer compared with the 24 patients with localized tumors bearing other chimeric transcripts (P = .04).

CONCLUSION

Results suggest a possible advantage in PFS for patients with localized disease and fusion type I transcripts, although this will require prospective validation with a larger number of patients and longer follow-up periods.

An 8-year follow-up of 450 sons of alcoholic and control subjects

BACKGROUND

Between 1978 and 1988, 453 sons (age range, 18-29 years) of alcoholic and control subject were evaluated for their level of reaction (LR) to alcohol. This article presents the results of the 8.2-year follow-up of 450 of these men. The three goals were (1) to attempt to replicate results of the follow-up of the first 223 subjects, (2) to evaluate the potential impact of the quantity and frequency of drinking at the time of the original study on the relationship between LR and alcoholic outcome (ALC), and, most importantly, (3) to test if the relationship between family history (FH) and ALC might be mediated by LR in a subset of the sample.

METHODS

Face-to-face structured follow-up interviews were carried out with the subjects and separately with an additional informant, and blood samples, as well as urine specimens, were obtained for determination of state markers of heavy drinking and drug toxicology screens.

RESULTS

First, the rate of development of DSM-III-R abuse and dependence on alcohol was 14.1% and 28.6%, respectively, for family history positive (FHP) subjects, compared with 6.6% and 10.8%, respectively, for family history negative (FHN) men. Second, neither consideration of the quantity nor the frequency of drinking at the time of the original study, nor their combination, effectively diminished the relationships between LR and ALC. Third, among men who drank and demonstrated the 15% highest and lowest scores of LR at about the age of 20 years (ie, 30% of the relevant population), the correlation between FH and ALC was greatly reduced when LR was considered, but the correlation between LR and ALC was not greatly diminished when the impact of FH was evaluated.

CONCLUSIONS

In this sample of moderately functional white men, the development of alcoholism occurred in relationship to an FH of alcoholism, but alcohol abuse or dependence was unrelated to prior psychiatric disorders. For this group, LR at the age of 20 years was associated with future alcoholism in a manner that was independent of the drinking practices at the time of the original study. At least among those men with clearly high and low LR scores, these data are consistent with the conclusion that LR might be a mediator of the alcoholism risk.

Ethanol enhances the in situ phosphorylation of MARCKS and protein kinase C activity in primary cultures of astrocytes

Protein kinase C (PKC) plays an important regulatory role in astrocyte function. Chronic exposure to ethanol for 4 days resulted in an increase in Ca2+-dependent PKC activity in the supernatant fraction of astrocyte homogenates. Only Ca2+-independent PKC activity could be observed in the membrane fraction and this activity was unaffected by ethanol exposure. Chronic ethanol exposure also increased the in situ phosphorylation of MARCKS in permeabilized astrocytes both in the absence or presence of the PKC activator, phorbol 12 -myristate 13 -acetate (PMA). These results suggest an increase in the expression of one or more astrocytic PKC isoforms after chronic ethanol exposure.

Ethnicity and cure rates of Texas children with acute lymphoid leukemia

BACKGROUND

Ethnic differences in the survival of children treated for acute lymphoid leukemia (ALL) have been described in several locations. Children of African, Polynesian, Native American, and Mexican ancestry had a less favorable outcome than children of European ancestry when treated in a similar manner by the same physicians and nurses.

METHODS

We reviewed the medical records of the 94 European-American (E-A) and 84 Mexican-American (M-A) Texas children registered and treated in national collaborative ALL therapy trials at the M. D. Anderson Cancer Center in Houston between 1974 and 1985 and followed through June 1994. Information was collected regarding age, sex, presenting clinical features, risk for relapse grouping, protocol assignment, event free survival, and the financial status of their families. Cure was defined as initial continuous complete remission for more than seven years and cessation of therapy for more than four years. Presenting characteristics of E-A and M-A children were compared, and then related to cure rates by univariate and multivariate analyses. Event free survival rates of E-A and M-A children were determined together and by sex.

RESULTS

Comparing presenting features, financial status as identified by pay code was significantly less for M-A children. Other features were not significantly different. By univariate analysis, an age of 2 to 6 years, female sex, initial white blood cell count below 10,000/microL, low risk grouping, registration on the most recent protocol, and full pay status were significantly associated with higher cure rates. By multivariate analysis, male gender, high risk group, and registration on earlier protocols were found to be significantly associated with a low cure rate. Event free survival and cure rate were lower for M-A children, but the differences were not statistically significant.

CONCLUSIONS

Further study of larger numbers of patients, including contemporary immunophenotypic and genotypic characterization of ALL, is needed for better definition of possible ethnic differences. Ethnicity and financial status should be included in the analysis of clinical trials of ALL therapy.

Significance of cytogenetic clonal evolution in chronic myelogenous leukemia

PURPOSE

To describe the incidence and significance of clonal evolution patterns.

PATIENTS AND METHODS

We analyzed 264 patients with Philadelphia chromosome (Ph)-positive chronic myelogenous leukemia (CML) who developed clonal evolution between 1967 and 1993.

RESULTS

The median survival time following clonal evolution was 19 months. Factors associated with worse survival (P < .01) were as follows: chromosome 17 abnormality or chromosomal translocations other than Ph, high percentage of abnormal metaphases, longer time to clonal evolution, and presence of other accelerated-phase features. A recursive partitioning technique (CART) identified different risk groups. The best group (37 patients; no chromosome 17 abnormality, abnormal metaphases < 16%, and interval to clonal evolution < or = 24 months) had an estimated median survival time of 54 months. The worst two groups included 27 patients with chromosome 17 abnormalities and > or = 36% abnormal metaphases (estimated median survival time, 6 months), and 22 patients with other accelerated features and > or = 16% abnormal metaphases (estimated median survival time, 7 months). The intermediate group had an estimated median survival time that ranged from 13 to 24 months. Prior interferon therapy evaluated within risk groups showed a significant survival advantage only in the intermediate-risk group. A multivariate analysis showed similar results, and identified the following independent poor prognostic variables: chromosome 17 abnormality, percentage of abnormal metaphases (cutoff, 24%), longer time to clonal evolution (cutoff, 24 months), other accelerated-phase features, and no prior interferon therapy. Patients with none, one, two, three, or more of the first four features had median survivals times of 51, 24, 14, and 7 months, respectively.

CONCLUSION

The prognostic significance of clonal evolution in CML is not uniform and is related to the specific abnormality, time to its development, its predominance in metaphases, and the presence of other accelerated features, and it may be modified by specific therapies.

Design and results of phase I cancer clinical trials: three-year experience at M.D. Anderson Cancer Center

PURPOSE

Alternatives to the standard design for conducting phase I trials are proposed with increasing frequency. This study was undertaken to determine how phase I trials are currently conducted and to provide a basis for evaluation of evolving methodology.

SUBJECTS AND METHODS

All published phase I trials from a single institution over a 3-year period were reviewed to determine the method of selection of the recommended dose for a phase II trial of a new agent, type and extent of toxicity, number of patients treated at the recommended dose, and clinical response.

RESULTS

All 23 published trials used the standard method of entering cohorts of patients at increasing dose levels and observing toxic effects to determine the dose recommended for phase II study. Among 610 patients, 26% were treated at or within 10% of the recommended dose and 35% were treated with less than 50% of the recommended dose or on a trial that yielded no recommended dose. Among 18 trials using agents previously tested in humans, fewer patients were treated at much less than the recommended dose. For trials in which myelosuppression was dose-limiting, the estimated probability of serious myelosuppression associated with the recommended dose ranged from 23% to 66%. Nineteen patients (3%) responded to therapy.

CONCLUSION

This summary of phase I trials recently conducted at M.D. Anderson Cancer Center confirms the need for alternative methods, provides baseline information against which alternatively conducted trials can be compared, and demonstrates some practical clinical trial issues not generally considered when alternative methods are proposed.

Adenocarcinoma as an independent risk factor for disease recurrence in patients with stage IB cervical carcinoma

Between 1960 and 1989 1538 patients were treated with initial radiation therapy for FIGO Stage IB squamous cell carcinoma (SCC) of the cervix and 229 patients were treated for Stage IB adenocarcinoma (AC). The overall 5-year survival rates for patients with SCC and AC were 81 and 72%, respectively (P < 0.01). Patients with AC more often had a maximum cervical diameter < 4 cm than those with SCC (53% versus 47%). For 903 patients with tumors > or = 4 cm, 73% of those with SCC survived > or = 5 years compared with only 59% of those with AC (P < 0.01). Although there was no significant difference in the rate of pelvic disease recurrence for patients with AC or SCC tumors > or = 4 cm (17% versus 13%, P = 0.16), the rate of distant metastases was greater for patients with AC (37% vs 21%, P < 0.01). For patients with tumors > or = 4 cm, prognosis was strongly correlated with tumor size (P < 0.01) and lymphangiogram findings (P < 0.01) but not with age (P = 0.58) or tumor morphology (exophytic versus endocervical) (P = 0.33); a trend toward better survival in 165 patients who underwent adjuvant hysterectomy (78% versus 71%) was not significant (P = 0.09). Multivariate analysis confirmed a highly significant independent association between histology and survival; patients with tumors > or = 4 cm in diameter that were AC had an estimated risk of death 1.9 times that of patients with SCC (P < 0.01). These results provide strong evidence that patients with AC of the cervix have a poorer prognosis than those with SCC of similar stage and tumor diameter, reflecting primarily a higher rate of distant metastases in patients with AC.

Platelet monoamine oxidase activity levels in subgroups of alcoholics: diagnostic, temporal, and clinical correlates

Platelet monoamine oxidase (MAO) activity levels were measured in 47 male inpatient alcoholics to determine whether this biological marker might be useful in differentiating subtypes of alcoholics. Of the subgrouping methods tested, only type 2 alcoholics defined by the criteria of Gilligan et al had significantly lower platelet MAO activity than type 1 alcoholics at intake, but this finding was not stable over time in a subset of subjects. Neither separating male veteran alcoholics into either of two other variations of the type 1/type 2 subtypes, nor classifying the sample into primary alcoholics versus primary ASPD with secondary alcoholism categories, yielded significant differences between subgroups. Generally, enzyme activity levels (Vmax) were higher about 10 days after stopping drinking compared to platelet MAO values determined in thrombocytes obtained after approximately 4 weeks abstinence; these levels remained relatively stable 3 months later in a cohort of subjects. Tobacco smoking was significantly negatively correlated to platelet MAO activity levels.

The microcirculatory effects of peripheral sympathectomy

Microvascular physiology following peripheral artery sympathectomy was evaluated in seven hands with refractory pain (n = 7) and ulceration (n = 7) by serial isolated cold stress testing, which measures digital temperature and cutaneous perfusion (laser Doppler fluxmetry). All patients (n = 6) had vasospasm (secondary Raynaud's phenomenon) and arteriographically proven digital and palmar occlusive disease. Microcirculatory flow responses were correlated with symptoms and signs (including ulcer healing) before and after (2-8 weeks, 12-15 weeks, and 24 weeks) peripheral sympathectomy. Baseline data were compared with those of controls (n = 7 extremities). Following surgery, all seven hands had diminished pain; six had ulcer healing and one had ulcer reduction. Isolated cold stress testing demonstrated abnormalities in temperature and laser Doppler fluxmetry response between patients and controls. Although total flow (reflected by temperature) was not significantly increased after surgery, peripheral sympathectomy increased nutritional flow in these patients with combined vasospastic vessels and occlusive injury. The clinical changes observed following peripheral sympathectomy appear to be related to postsurgical correction of abnormal arteriovenous shunting and to improved nutritional blood flow to ischemic areas. This accounts for the resultant diminution of pain and healing of ulcers observed in these patients after surgery.

An evaluation of type A and B alcoholics

Evaluations of 1539 alcohol-dependent subjects (including 512 women) were carried out in an attempt to replicate the Type A/B dichotomy suggested by Babor et al. (1992). The subjects are participants in the Collaborative Study on the Genetics of Alcoholism (COGA), and each was evaluated using a face-to-face structured interview. Following the procedure of Babor et al. (1992), data were used to create 17 domains, and a k-means clustering method was invoked to generate a two-cluster solution. Thirty-one per cent of the males and 25% of the females fell into the Type B group, with overall R2 of 0.22 and 0.24 for males and females, respectively. The scores in each of the 17 domains and the analyses of the clinical characteristics for Type A and B subjects were, in general, consistent with the earlier onset and more severe course for Type B men and women. The ability of the domains to identify subgroups of alcoholics remained robust even after the exclusion of alcohol dependent subjects with antisocial personality disorder (ASPD) and those with an onset of alcohol dependence before age 25 years. The present analyses suggest that five of the 17 domains might be especially useful in identifying Type A and B groups.

Fatal craniocervical necrotizing fasciitis in an immunocompetent patient: a case report and literature review

BACKGROUND

Craniocervical necrotizing fasciitis (CCNF) is a rapidly progressive, severe bacterial infection of the superficial fascial planes of the head and neck. Group A beta-hemolytic Streptococcus, staphylococcus aureus, and obligate anaerobic bacteria are common pathogens. The disease usually results from a dental source or facial trauma. Extensive fascial necrosis and severe systemic toxicity are common manifestations of CCNF. Recently the lay press has referred to necrotizing fasciitis in several articles about "flesh eating" bacteria, which have resulted in several deaths.

METHODS

We report the first case of a fatality in an otherwise immunocompetent patient. The patient was a 66-year-old black man with no identifiable source of infection and no history or evidence of immunocompromising disorders.

RESULTS

Despite aggressive surgical debridement and broad-spectrum antibiotic coverage, he died 30 hours after admission from multisystem organ failure secondary to overwhelming sepsis.

CONCLUSION

Treatment consists of early recognition of CCNF combined with aggressive surgical debridement and drainage of the involved necrotic fascia and tissue along with broad-spectrum intravenous antibiotic coverage. Although 11 other fatal cases of CCNF have been previously reported, all had an underlying medical problem which created an immunocompromised state, usually diabetes mellitus or chronic alcoholism. We present a case report and literature review along with a discussion of the related anatomy.

P22 Arc repressor: role of cooperativity in repression and binding to operators with altered half-site spacing

Dimers of P22 Arc repressor bind to half-sites of the 21 bp arc operator and interact cooperatively to stabilize a DNA-bound tetramer. Mutation of Ser35 (a residue in the dimer-dimer interface) to Arg or Leu disrupts cooperative binding. The mutant proteins have near wild-type stabilities, give operator footprints like wild-type, and prevent binding of RNA polymerase to the Pant promoter in vitro. These mutants are, however, largely inactive in vivo. Thus, although cooperativity is not structurally required for repression, it appears that the additional DNA-binding energy from dimer-dimer cooperativity is required for normal biological function. Altering the spacing between the DNA half-sites by even one base-pair eliminates dimer-dimer cooperativity, indicating that Arc dimers need to be oriented correctly by half-site binding to allow the interactions that stabilize the tetrameric complex.

Effect of magnesium on secretion of platelet-derived growth factor by cultured human umbilical arterial endothelial cells

Conditioned media were prepared by incubating human cultured umbilical arterial endothelial cells for 48 h in magnesium (Mg) sufficient (900 microM) and deficient (100 microM) conditions. Minimum essential media (MEM) are designated as [900]- and [100]-MEM, respectively. After the incubation, a portion of the [100]-MEM media was adjusted from 100 to 900 microM magnesium ([100-900]-MEM). Smooth muscle cells were incubated with the three media and their growth rates were determined by [3H]-thymidine incorporation and cell counting. The growth rate in [100-900]-MEM was significantly higher than in [900]- or [100]-MEM. When platelet-derived growth factor (PDGF) was neutralized by the addition of a mixture of anti-PDGF-AA and -BB, [3H]-thymidine incorporation in [100-900]-MEM decreased by 12.5 per cent, but only by 4.9 per cent in [900]-MEM. These results indicate that magnesium deficiency increases the secretion of PDGF by endothelial cells. This is also supported by the results of the radioimmunoassay for PDGF-BB; the quantity of PDGF in the magnesium-deficient media was greater than in the magnesium-sufficient media.

Lack of involvement of protein kinase C in ethanol-induced inhibition of metabotropic-glutamate receptor function in primary cultures of astrocytes

The stimulation of [3H] inositol phosphate (InP) formation by the selective metabotropic-glutamate receptor agonist, 1S, 3R-ACPD, was significantly reduced in rat cortical astrocytes chronically exposed to 100 mM ethanol for 4 days. Under the same conditions, chronic ethanol either increased or did not affect the InP responses to norepinephrine and carbachol, respectively. The InP responses to all three agonists were sensitive to phorbol 12-myristate 13-acetate. Although the protein kinase C inhibitors, calphostin C and staurosporine, significantly relieved the ethanol induced inhibtion of the InP response to 1S, 3R-ACPD, these responses were still significantly less than corresponding values obtained from control cells treated with these inhibitors. The data suggests that mechanisms in addition to protein kinase C are responsible for the ethanol induced inhibition of metabotropic-glutamate function.

Death education in paramedic programs: a nationwide assessment

In an exploratory study, we obtained information on death education in paramedic programs. A self-administered survey was sent to all U.S. paramedic training programs (N = 537). The survey ascertained the method of instruction, educational supplements, assessment techniques, and integration of death education into general course work. The status of past, present, and future death education offerings in paramedic programs was also elicited. Analysis was performed on the usable surveys (response rate = 51%). The overwhelming majority (95%) of programs offer death education, with more offerings now than 10 years ago. Legal--ethical topics were the most often included death-related instruction. In the majority of programs, a lecture (didactic) format was used for instruction and closed-ended tests were used for assessment. Results on other educational supplements and assessment techniques are also presented.