Biomedical subjects
Publications and source records attributed to L Dean.
10'-Desmethoxystreptonigrin, a novel analog of streptonigrin produced by Streptomyces albus, was discovered in a screen for inhibitors of farnesylation of RAS p21 protein. The compound was isolated from the fermentation broth and its structure determined. It is markedly cytotoxic to several human tumor cell lines and also exhibits potent broad-spectrum antibacterial activity.
This paper examines the relationships between instrumental and emotional social support and the experience of grief reaction in a sample of 180 gay men who had lost a lover or close friend to AIDS during the first 5 years of the epidemic. Structured, face-to-face interviews were conducted in mid-1985. Grief reaction was assessed through a newly developed 12-item scale (alpha = 0.85). Availability and adequacy of instrumental and emotional support were assessed with reference to the tasks of caretaking and emotional pain experienced during the lover's or close friend's illness with AIDS. The findings indicate that gay men who lost a lover or close friend to AIDS experienced symptoms of grief similar to those reported in studies of bereaved spouses and parents. The intensity of these grief reactions appears to be influenced by a number of factors. First, more intense grief reactions were observed among those who had taken care of their lover or close friend during his illness compared with those who did not act as caretakers. Second, while the simple availability of instrumental and emotional support was unrelated to grief reactions, the perceived adequacy of both types of support was strongly related to the level of grief. Respondents who had received inadequate help with caretaking responsibilities experienced more intense symptoms of grief subsequent to the death compared with those who reported receiving adequate caretaking support. Similarly, respondents who did not obtain adequate emotional support for the pain they experienced during the course of the illness reported more intense symptoms of grief compared with those who felt they had received adequate support.(ABSTRACT TRUNCATED AT 250 WORDS)
Proton nuclear magnetic resonance (NMR) imaging has the potential to serially assess left ventricular (LV) volumes with optimal accuracy because it is a high-resolution, three-dimensional, noninvasive modality. Previous NMR studies to assess LV volumes have been suboptimal, as they have used either planes aligned with the axes of the body, which are compromised by partial volume effects, or spin-echo techniques that have been time-consuming to acquire and analyze. Accordingly, for LV volume measurement, we developed a gradient-echo (cine) NMR strategy that uses two orthogonal planes intersecting along the intrinsic long axis of the heart (two-chamber and four-chamber). This approach was validated against calibrated contrast biplane LV cineangiography (CATH) and also compared with a previously reported short-axis spin-echo NMR method. Twenty-one patients underwent CATH and NMR (long-axis, n = 21; short-axis, n = 14) within a 3-day interval. Although both long- and short-axis NMR LV volumes and ejection fractions correlated well with CATH (r greater than 0.90, p less than 0.001 in all), end-diastolic volumes by both long-axis (161 +/- 85 ml) and short-axis (151 +/- 81 ml) NMR were systematically less than those by CATH (182 +/- 85 ml) (p less than 0.05). Consequently, ejection fractions by long-axis (48 +/- 17%) and short-axis (49 +/- 17%) NMR consistently underestimated those by CATH (54 +/- 16%, p less than 0.05). End-systolic volumes by long-axis (94 +/- 71 ml) and short-axis (87 +/- 72 ml) NMR were not significantly different from those by CATH (92 +/- 69 ml). Both NMR techniques had low intraobserver and interobserver variation (less than 11%); however, short-axis spin-echo NMR involved longer acquisition/reconstruction (35 versus 18 minutes) and analysis (25 versus 10 minutes) times. We conclude that both short-axis spin-echo and long-axis gradient-echo NMR approaches reliably estimate LV volumes. Currently, the long-axis strategy appears more practical for clinical use because the scan and analysis times are relatively short.
Janthinocins A, B and C are novel antibacterial agents produced by Janthinobacterium lividum. They were isolated from fermentation broths and characterized by UV, IR, NMR and mass spectroscopy. They are cyclic decapeptide lactones with marked activity against aerobic and anaerobic Gram-positive bacteria and are 2 to 4 times more potent in vitro than vancomycin. Janthinocins A and B were also found to be effective in a Staphylococcus aureus systemic infection in mice.
This study evaluated an attempt at 38 workplaces to help employees stop or reduce their levels of smoking. In past research, worksite support groups, in combination with a media smoking cessation program and self-help manuals, were found to be effective in helping employees quit smoking. Unfortunately, recidivism was found at the follow-up evaluations. The present study replicated the results of the previous worksite smoking cessation program with support groups, a television intervention, and self-help manuals. At this postpoint, 42% of employees provided groups plus incentives were abstinent compared to only 15% who were only provided self-help materials. An important difference in this study was that there were also monthly follow-up support groups and incentives. Work settings can be a source of stress and conflict, which can precipitate relapse. At a 12-month follow-up, 26% of those participants who were provided support and incentives were abstinent compared to 16% who were only provided the self-help materials.
This report describes progress made to date on a study of the impact of the AIDS epidemic on the gay community of New York City. Using a model of the life stress process described by Barbara Dohrenwend and her colleagues, the AIDS epidemic was conceptualized as a community stressor resulting in two key stress-inducing events: death of loved ones due to AIDS and potential illness and death of oneself due to infection with human immunodeficiency virus (HIV). It was hypothesized that these stressors would be significantly related to three domains of health outcomes: sexual behavior, drug and alcohol use, and psychological distress. Descriptive trends over time are provided for both the health outcome variables and the stressor variables. Cross-sectional analyses for 3 years of data provide evidence in support of the main hypothesis. The implications of these findings are discussed from the standpoints of methodology, public health, and the psychology of stress processes in community settings.
The impact of a restrictive smoking policy on the behavior and attitudes of smokers and non-smokers was assessed by surveying random cross-sectional samples of hospital employees before, six months after and 12 months after the policy was implemented, and comparing responses with those of employees of a hospital with no restrictive policy. Effectiveness of policy implementation was also evaluated. Results indicated that the policy was well-publicized and was approved by virtually all the non-smokers and the majority of the smokers. Following implementation, employees in the smoking policy hospital were less likely to report being bothered by smoke at their work stations than were employees of the comparison hospital. Six months and one year after the policy change, smokers reported lower smoking rates while at work, although quit smoking rates and home smoking rates were similar in both hospitals.
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A major 68-kDa protein in ram rete testis fluid (RTF) is shown to be chemically and immunologically indistinguishable from albumin in ovine serum. Data obtained with two-dimensional gel electrophoresis of RTF demonstrate the presence of additional proteins with a molecular mass of 68 kDa that do not react with antisera against sheep serum albumin. Biochemical characteristics of albumin preparations isolated by immunoaffinity chromatography from ovine serum and from RTF were compared. Albumin from both sources had the same apparent molecular mass of 68 kDa, the same isoelectric point of approximately 4.2, and neither bound specifically to Concanavalin A. Analysis of tryptic peptide maps, obtained with reverse-phase high-pressure liquid chromatography, indicated no significant differences between digests of the two purified albumin preparations. Results indicate that RTF albumin and serum albumin are the same protein, which implies that RTF albumin may originate from serum. Albumin levels in RTF, collected from different rams and measured by radioimmunoassay, varied between 46 and 164 micrograms/ml, constituting between 11 and 17% of total RTF protein, while albumin levels in sheep plasma were 40,000 micrograms/ml. The protein composition of RTF is discussed in relation to the relative amounts of various components contributed by testis cells and the amounts derived from serum.
Seven patients with newly diagnosed metastatic osteosarcoma underwent simultaneous resection of the primary tumor and metastases following intravenous (IV) neoadjuvant chemotherapy. Histologic response was assessed in all tumor specimens. Disparate responses were noted between primary tumor and metastases and, in some cases, between two or more metastatic tumor deposits. The diverse histologic response to neoadjuvant chemotherapy suggests tumor cell heterogeneity. Changing postoperative therapy on the basis of the histologic response induced in the primary tumor may not be appropriate.
Xylocandin is a complex of novel peptides with potent antifungal activity that is produced by Pseudomonas cepacia ATCC 39277. The complex was isolated from the fermentation broth by extraction with butanol-methanol, 9:1, followed by collection of the precipitate formed upon concentration of the solvent extract. Purification was effected by chromatography on reversed phase and size exclusion gels followed by TLC on silica gel. These techniques afforded eight components: A1, A2, B1, B2, C1, C2, D1 and D2. A mixture of the two closely related components, xylocandins A1 and A2, displayed potent anticandidal and antidermatophytic activities in vitro. The activity was diminished by the presence of serum or vaginal washings. No antibacterial activity was demonstrable.
Two novel antibiotics, catacandin A and catacandin B, were isolated from the fermentation broth of the bacterium, Lysobacter gummosus, by extraction and adsorption, reverse-phase and gel filtration chromatography. On the basis of their physico-chemical properties, they are acyltetramic acids that are easily distinguishable from others in this class. Catacandin A and catacandin B possess good anticandidal activity.
Cholesterol content of the high-density lipoproteins has become of interest in evaluating the risk of development of coronary heart disease. There is an inverse relationship between high-density lipoprotein cholesterol and risk. The authors found a significant bias (11.1 mg/dl; 0.289 mmol/l) in a comparison of a rapid cholesterol oxidase method and the Abell--Kendall method for quantitating high-density lipoprotein cholesterol. The two methods did not differ in the usual range of total serum cholesterol. Since methodology may vary, each laboratory's performance should be assessed prior to use of published risk factor data. The authors then studied normal male and female volunteers aged 20 to 35 years. They conclude that high-density lipoprotein cholesterol is of value as a risk factor indicator in this age group. The relationship of total serum cholesterol to high-density lipoprotein cholesterol was studied. The authors conclude that they are independent indicators. Further, there is a range of efficiency of the high-density lipoprotein lipid-clearing function. Finally, the authors attempted unsuccessfully to predict high-density lipoprotein cholesterol from lipoprotein electrophoresis patterns.
A study of 533 women with very low urinary oestriol excretion during the third trimester of pregnancy showed an incidence of major fetal malformations among their infants of 7-1% and a perinatal mortality rate of 14-6%. Thirteen of the malformations were cases of anencephaly, and 26 of the 78 perinatal deaths were due to or associated with major fetal malformations. The incidence of these complications was higher when maternal oestriol excretion was lower. Routine screening by urinary oestriol assay, with fetal radiography when values below 20-8 mumol/24 hours (6 mg/24 h) are detected is the most reliable method of detecting anencephaly before birth.
A survey of tow truck services operating in a defined area of the south-east suburbs of Melbourne was undertaken to determine their potential for delivering emergency medical care at the scene of crashes. Most towing firms have an association with a panel-beating shop, and operate within a limited area of one to three miles radius. The rapid response of tow trucks to crash scenes is due to their well-developed intelligence network of "spotters" and the short distances the trucks travel. Very little first aid is provided by the drivers, although one-fifth had some first aid training at some time. In about one-half of the calls to crashes a damaged vehicle is still at the scene, in about 20% an ambulance is called, and in about 5% a hospital admission occurs. Direct observation of 22 crashes suggests that on average, tow trucks arrive at a crash scene five minutes before the ambulance, and fifteen minutes before the police. There is a good case for making first aid training a preerequisite for issue of a tow truck operator's license.