Rat hepatocytes isolated from alcohol-induced fatty liver have an increased sensitivity to anoxic injury

The aim of this study was to determine whether rat hepatocytes isolated from steatotic or nonsteatotic livers have different thresholds for injury due to anoxia-reoxygenation. Rats were fed ethanol or control diets for 8 weeks. Histology showed that more than 75% of the hepatocytes in alcohol-fed and less than 3% in control animals contained fatty vacuoles. The glycogen content was significantly reduced in steatotic livers. Isolated hepatocytes were cast in agarose gel threads and perfused with Krebs-Henseleit bicarbonate buffer. Cell viability was determined by Trypan Blue (TB) exclusion; cell injury was determined by lactate dehydrogenase (LDH) release; and superoxide anion (O2.-) was determined by lucigenin-enhanced chemiluminescence (LCL). During the pre-anoxic basal perfusion the following occurred: viability was 86% +/- 1% and 85% +/- 1%; LDH release was 16 +/- 3 and 15 +/- 3 mU/min; and LCL was 4 +/- 1 and 5 +/- 1 nA in steatotic and nonsteatotic hepatocytes, respectively. Cell viability decreased slightly under 4 hours of aerobic perfusion without differences between the two groups. In contrast, fatty hepatocytes died much faster than did control hepatocytes during anoxia; after 3 hours viability was 17% +/- 8% vs. 60% +/- 2% (P < .001), respectively. With reoxygenation following 2 hours of anoxia, the changes in viability, in LDH release, and in LCL were similar in both groups. These results indicate that in hepatocytes isolated from alcohol-fed rats when compared with control hepatocytes: 1) cell viability under aerobic conditions is not influenced; 2) anoxic injury is significantly increased; 3) a reduction in the hepatic glycogen stores, which may contribute to the enhanced sensitivity to anoxia, can be demonstrated; and 4) O2.- generation and cell injury occurring immediately after reoxygenation do not appear to be affected.

Truncation of the amino terminus of human apolipoprotein A-I substantially alters only the lipid-free conformation

An amino-terminal deletion mutant (residues 1-43) of human apolipoprotein A-I (apo hA-I) has been produced from a bacterial expression system to explore the structural and functional role of these amino acids, encoded by exon 3, in apo hA-I. Lipid binding of apo delta (1-43)A-I and lipid binding of apo hA-I are very similar as assessed by surface activity, lipid association with palmitoyloleoylphosphatidylcholine (POPC) vesicles, and lipid association with plasma lipoproteins. Preliminary kinetic measurements appear to show that the reactivity of lecithin:cholesterol acyltransferase (LCAT) with the mutant is slightly decreased compared to wild-type apo hA-I. Collectively, these results indicate that the N-terminal region is not necessary for lipid binding or activation of LCAT. In contrast, there are significant structural differences between lipid-free apo delta (1-43)A-I and apo hA-I, as judged by denaturant-induced unfolding, binding of the fluorescent probe 1-anilinonaphthalene-8-sulfonate, surface balance measurements, and far- and near-ultraviolet circular dichroic spectroscopy. All spectral and physical measurements indicate apo delta (1-43)A-I has a folded, tertiary structure, although it is significantly less stable than that of apo hA-I. It is concluded that the N-terminal 43 residues are an important structural element of the lipid-free conformational state of apo hA-I, the absence of which induces a fundamentally different fold for the remaining carboxy-terminal residues, compared to those in native apo hA-I.

Proteins but not nucleic acids are molecular targets for the free radical attack during reoxygenation of rat hepatocytes

Isolated rat hepatocytes generate large amounts of reactive oxygen species and suffer a significant cell injury during postanoxic reoxygenation. The aim of this study was to determine whether oxidation of proteins and nucleic acids occurs during reoxygenation and whether their damage is related to the development of hepatocyte injury. Isolated perfused rat hepatocytes were exposed sequentially to 1 h of aerobic control, 2.5 h of anoxia, and 2 h of reoxygenation. Protein oxidation was determined by measuring the hepatocyte protein carbonyl content. DNA and RNA oxidation was assessed by measuring the 8-hydroxydeoxyguanosine and 8-hydroxyguanosine adducts, respectively. The control preanoxic carbonyl content was 6.48 +/- 1.03 nmol/mg protein. The preanoxic 8-8 hydroxydeoxyguanosine and 8-hydroxyguanosine levels were 4.76 +/- 1.22 pmol/ml and 14.19 +/- 2.17 pmol/ml, respectively. During anoxia, protein and nucleic acid oxidation did not change significantly. With reoxygenation, the protein carbonyl content increased significantly within 30 min, reaching a value of 10.25 +/- 1.58 nmol/mg. The nucleic acid oxidation level remained stable. Perfusion with 100 muM of during reoxygenation abolished protein oxidation. These results indicate that in rat hepatocytes during the early phase of reoxygenation: (1) the protein oxidation level increased significantly above the preanoxic aerobic values; (2) DNA and RNA oxidation does not appear to occur; and (3) free metal-mediated free radical reactions are involved in the oxidative protein damage.

Smoking behaviours and beliefs of older Australians

Reviews of the effects of smoking on health have concluded that older smokers can experience considerable health benefits from giving up smoking. In a representative population survey of people aged 15 years and over in South Australia, the percentage of people aged 60 years and over who were smokers was 13.5 per cent (95 per cent confidence interval 10.9 to 16.2 per cent). Compared with smokers aged under 60 years (n = 727), older smokers (n = 88) were significantly more likely: to be less convinced of the effects of smoking on health; to perceive that they were not personally at risk from their smoking in the future; to believe that smoking had not affected their own health so far; and to believe there was a daily level of cigarette consumption that was safe. Strategies to encourage older people to consider more objectively how smoking impairs daily living, including personal disclosure of smoking-related damage through lung-function testing, deserve further research.

Nephrotic syndrome in Trinidadian children

57 children with idiopathic nephrotic syndrome who were seen at two hospitals in Trinidad between 1989 and 1995 (median follow-up period, 38 months) were classified according to their response to glucocorticoids. 27 (47%) were two to six years old at presentation; 37 (65%) were of East Indian descent, 7 (12%) were of African descent, and 12 (21%) were of mixed race. 55 (96%) responded to glucocorticoids. Renal biopsies in 15 patients revealed membranoproliferative glomerulonephritis and membranous nephropathy in the two patients who had not responded to glucocorticoids. Ten patients showed mesangial hypercellularity, associated with immunoglobulin deposits in 7 cases. Age, presentation with nephrotic features, mesangial hypercellularity and immunoglobulin deposits did not predict for unresponsiveness to glucocorticoids. These findings may be explained by the predominance of East Indians in the study group.

Trends in prevalence and acceptance of workplace smoking bans among indoor workers in South Australia

OBJECTIVE

To compare the reported prevalence and acceptance of bans on smoking in the workplaces of a representative sample of adults in South Australia between 1989 and 1994.

DESIGN

Independent cross-sectional representative population surveys.

SETTING

South Australian population.

PARTICIPANTS

Adults who indicated they were employed mainly indoors, for the years 1989 (875 respondents), 1991 (1472), 1992 (1288) and 1994 (1273).

MAIN OUTCOME MEASURES

Percentage reporting total bans on smoking at work; percentage reporting compliance with bans all or nearly all the time; percentage reporting preference for total bans at work.

RESULTS

The percentage of indoor workers subject to a total ban on smoking at work increased from 32% in 1989 to 62% in 1994 and preference for a total ban increased during the same period from 26% to 52%. Reported compliance with restrictions and bans was very high. In 1994, 16% of workers still had no restrictions on smoking at work, but only 3% preferred this arrangement.

CONCLUSION

The data suggest that smoking bans are now the norm for indoor workers and that further gains in promoting and supporting workplace bans will be made by directing efforts at smaller workplaces, where unrestricted smoking is most prevalent.

Developed and resolving lesions in porcine proliferative enteropathy: possible pathogenetic mechanisms

Proliferative enteropathy, caused by Lawsonia intracellularis, offers the opportunity to examine bacterial mechanisms that influence epithelial cell proliferation. Ultrastructural features of developed and resolving lesions included the presence of enlarged intestinal crypts containing undifferentiated immature epithelial cells and an absence of goblet cells. Numerous intracytoplasmic bacteria, identified as L. intracellularis, were consistently present within affected cells. In recovering intestinal tissue, additional features were (1) the common presence of pale, swollen, protruding epithelial cells, (2) shrunken, degenerate epithelial cells, (3) apoptotic bodies in both epithelial cells and macrophages, (4) the reappearance of normal goblet cells, and (5) reduced numbers of L. intracellularis within lesions. Bacteria were released from cells via cytoplasmic and cellular protrusions into the intestinal lumen. It is speculated that the presence of the intracytoplasmic bacterium, L. intracellularis, may disrupt normal processes of cell growth, differentiation or apoptosis in the intestinal epithelium.

Generation of a potent chimeric toxin by replacement of domain III of Pseudomonas exotoxin with ricin A chain KDEL

Following cellular uptake, Pseudomonas exotoxin (PE) is cleaved by cellular protease which generates an enzymatically active C-terminal fragment (amino acids 280-613). This 37 kD fragment translocates to the cell cytosol where it ADP-ribosylates elongation factor 2 and inhibits protein synthesis. A recombinant hybrid toxin (designated PE-RTA) in which the ADP-ribosylation domain (domain 111) was replaced by the RNA N-glycosidase domain of ricin (the A chain or RTA) has been produced in E. coli. The hybrid toxin effectively and specifically depurinated 28S ribosomal RNA, indicating that the ricin A moiety folded into its native conformation. The cytotoxicity of PE-RTA for L929 cells was approximately 100-fold less than either native PE or whole ricin. However, the addition of the tetrapeptide KDEL to the C-terminus of PE-RTA (producing PE-RTA KDEL) increased cytotoxicity to the level of the native toxins. By analogy to PE, both PE-RTA and PE-RTA KDEL would be proteolytically cleaved within PE domain II during cell entry. A single amino acid substitution, believed to disrupt an essential step in the transport of the catalytically active PE fragment to the cell cytosol (Trp281 to Ala: Zdanovsky, A.G., Chiron, M., Pastan, I., and FitzGerald, D. J. (1993) J. Biol. Chem. 268, 21791-21799), reduced the cytotoxicities of both PE and PE-RTA KDEL by approximately 100-fold. Taken together, these data show that the ricin A chain component of the hybrid toxin requires essential PE-derived sequences at both the N- and C-termini of the translocating fragment. Clearly, in the context of this fusion protein, ricin A chain cannot effect its own transfer to the cytosol.

Can we target smoking groups more effectively? A study of male and female heavy smokers

BACKGROUND

In recent years a number of studies have examined subgroups within the smoking population. These studies have provided information which facilitate improved targeting of programs and interventions to help smokers quit. Despite this there have been few population studies which have described male and female heavy smokers and compared their characteristics.

METHODS

We used representative population data on 789 smokers to examine differences between light and heavy smokers of each gender and between male and female heavy smokers directly.

RESULTS

Of those who smoked, 35% of males and 24% of females were classified as heavy smokers and represent a large target group within the smoking population. Whereas a light smoker was characterized as smoking a median of 12.5 cigarettes per day, the heavy smoker smoked a median of 32 cigarettes per day. Univariate comparison of heavy smokers and light smokers showed a number of statistically significant differences according to demographics, in smoking behaviors and knowledge, in beliefs about smoking, in smoking characteristics, and in other health indicators. Because of interactions between gender and work/leisure day smoking variation, separate logistic regression models based on gender were fitted to the data. Again, compared with light smokers, several significant differences emerged for both heavy female and heavy male smokers under the headings mentioned above. Further logistic regression analyses showed differences between male and female heavy smokers when compared directly.

CONCLUSIONS

The smoking population of South Australia is not homogeneous and this segmentation study has shown the need for varying approaches to different segments when developing intervention programs.

Smoking-related beliefs and behaviour of South Australians with diabetes

Data cumulated from three representative population surveys (n = 9402) in South Australia were used to determine smoking prevalence of those aged 15 years or over with and without self-reported medically confirmed diabetes. Overall, smoking prevalence in the two groups did not differ. However, among those aged under 40 years with self-reported diabetes, smoking prevalence approached 55 per cent, which was significantly higher than in young respondents without diabetes (32 per cent). Diabetic smokers were no more likely than were nondiabetic smokers to have tried to quit or to be ready to quit; one-quarter of diabetic smokers had no thought of quitting or of modifying their habit. Smokers with diabetes were significantly more likely to be heavy smokers (43.5 per cent) than were nondiabetic smokers (23.4 per cent). Fewer smokers with diabetes tended to believe that smoking causes or aggravates heart disease or circulatory problems than did other smokers, although these differences did not reach statistical significance. Additional effort is required to find methods to assist people with diabetes to refrain from smoking.

Smoking-related beliefs and behaviour among adults with asthma in a representative population sample

BACKGROUND

Smoking and exposure to environmental tobacco smoke are inadvisable for adults with asthma.

AIMS

To determine the smoking prevalence and daily smoking rate of asthmatics and compare smoking-related beliefs and behaviours among smokers with and without asthma. To compare beliefs of asthmatics about passive smoking and asthma, how many are exposed at home and what they do when they are exposed, with people who do not have asthma.

METHODS

A representative population survey of 3019 South Australian adults aged 15 years and older interviewed in their own homes in late 1992.

RESULTS

Twenty-eight per cent of asthmatics were smokers; mean daily smoking rate was 17.6. Asthmatics had similar patterns of smoking, readiness to quit and quit attempt histories as people without asthma. More than 40% of smokers with asthma did not perceive that smoking had greatly affected their health, over half did not believe they were at risk in future and two-thirds did not think future health problems would be serious. Among non-smokers, despite being more convinced of the effects of passive smoking on asthma, and being more concerned about exposure, those with asthma were no more likely to take protective action in response to actual or imminent exposure than those without asthma. One in ten non-smokers with asthma were exposed to smoking at home.

CONCLUSIONS

The smoking habits of adults with asthma are cause for concern, with many asthmatic smokers perceiving they are not personally at risk from their smoking. Health education principles should be used by health professionals caring for asthmatic smokers to guide the selection and delivery of smoking cessation strategies. Prevailing restrictions on indoor smoking play an important role in protecting the respiratory health of non-smokers with asthma.

Low-rate smokers

BACKGROUND

Some smokers maintain a low daily smoking rate and do not appear to be addicted to nicotine (tobacco "chippers"). In a context of increasing social and environmental constraints on cigarette smoking, it is of interest to determine the population prevalence and the characteristics of low-rate smoking behavior.

METHODS

A representative population survey was used to determine the prevalence and the correlates of low-rate smoking (five or less cigarettes a day). A range of sociodemographic, contextual, cognitive, and smoking-behavior variables was examined.

RESULTS

Of 697 smokers age 20 years and over who had smoked for more than 2 years, 8.2% smoked five or less cigarettes a day; their average age was 39 years, and half were under 35 years of age; 88% had been smoking for 6 or more years; 86% were in the contemplation or preparation stages of readiness to quit. The significant independent predictors of being a low-rate smoker, compared to smoking at a higher daily rate, were perceiving quitting as not very difficult, smoking the first cigarette of the day more than 30 min after walking, buying packets of 30 or less cigarettes, and having not been advised by a doctor to quit.

CONCLUSIONS

There were few differences between low-rate and other smokers on the range of variables that we were able to assess in a population survey. Since there is no safe level of cigarette smoking, medical advice to quit and public-education campaigns could target low-rate smokers specifically. Such initiatives could make significant contributions to reducing overall smoking prevalence.

Ethnosensitive techniques in the treatment of the Hasidic patient with cancer

Hasidic Jews, members of the ultraorthodox sects, represent a cultural subgroup found predominantly in large urban areas. This article presents the authors' understanding of the origins and attributes of Hasidic culture and the sociocultural conflicts that arise when patients from this sheltered culture encounter modern institutions such as the oncology medical center. As a result of cultural and religious differences, both Hasidic patients and healthcare professionals find themselves confronting a set of unique issues related to the way in which the Hasidim deal with a cancer diagnosis. Key variables influencing the Hasidic patient's response include his or her cultural view of illness, understanding of the role of medicine, theological world view, issues related to Holocaust survivorship, and the sense of identity as expressed in ritual practice. In this age of multiculturalism, it is important to recognize the unique features of different ethnic groups. Doing so ensures that each group receives the same level of services without having to conform to an arbitrary norm. Attention to the ethnic and cultural characteristics of the patient with cancer has been shown to enhance the quality of professional intervention. Specific recommendations for intervention are offered for the oncology healthcare provider as clinician, mediator, and patient advocate.

Serological evidence implicating Neospora species as a cause of abortion in British cattle

By means of an immunofluorescence antibody test (IFAT), using in vitro cultured parasites as antigen, antibodies to Neospora species at titres > or = 1/1280 were found in 11 of 120 Scottish cattle that had recently aborted but in only one of 97 cattle from herds in which there had been no recent abortions (P < 0.01). The specificity of the antibodies was confirmed by the lack of cross reactivity between samples with high titres to Neospora and toxoplasma antigen in a direct agglutination test, and by the absence of reactivity at > or = 1/640 in the IFAT of convalescent sera from cattle infected experimentally with Toxoplasma gondii, Sarcocystis cruzi, Eimeria bovis, E alabamensis, Cryptosporidium parvum and Babesia divergens. These results demonstrate that Neospora species infection occurs commonly in aborting cattle in Britain, and that the IFAT may be a useful tool for investigating the infection.

Survival following intentional massive overdose of 'Ecstasy'

A case of intentional overdose with 18 'Ecstasy' tablets is described. 'Ecstasy' is a semi-synthetic hallucinogenic amphetamine and acute adverse reactions follow from the effects of sympathetic stimulation. To our knowledge this is the first reported case of massive intentional overdose reported in the literature.

P300 differences between non-alcoholic young men at average and above-average risk for alcoholism: effects of distraction and task modality

1. P300 event-related electroencephalographic potentials were recorded from 79 young adult males, cross-classified with respect to the presence/absence of a family history of alcoholism (FHA) and the presence/absence of a personal history of antisocial personality (ASP) disorder. P300s were elicited using visual and auditory oddball tasks. Each oddball task was repeated with a tracking task added as a distractor. 2. In general, distraction increased the latencies and reduced the amplitudes of P300s elicited by the oddball stimuli. The P300 latency increase occurred only in low risk ASP- and FHA- groups. There was no adaptive increase in P300 latency in the higher risk ASP+ and FHA+ groups. 3. Group differences in P300 were restricted to visual tasks. No interpretable group differences in P300 latency or amplitude were found during the auditory tasks.

Single fibre EMG studies in chronic fatigue syndrome: a reappraisal

Single fibre EMG studies were carried out on the right extensor digitorum communis muscle in 30 subjects with chronic fatigue syndrome and in 30 age and sex matched controls. Abnormal jitter was seen in five patients with chronic fatigue syndrome. Slight but significant differences between the mean consecutive differences in the remainder of the chronic fatigue subjects and the control subjects were recorded. Overall the differences were so minor that it seems unlikely that a disturbance of neuromuscular function as reflected by jitter measurement has a pathogenetic role. It is suggested that the increased jitter seen may be explained by the effects of the variability of motor unit firing rates on the myogenic component of the jitter.

Prolonged pregnancy: two years experience of offering women conservative management

A prospective study of 199 patients over a two year period, 1 Jun 90 to 31 May 92 at the Louise Margaret Maternity Wing, Cambridge Military Hospital, Aldershot was undertaken to audit the uptake of an offer of conservative management of prolonged pregnancy to women at 42 weeks gestation. The labour outcomes of patients opting for conservative or induction management plans were recorded and the increased workload introduced to the Ultrasound Unit measured. Of the 91/199 (45.7%) patients who chose to be managed conservatively, 20 (22.0%) developed an abnormal result of a test of fetal surveillance, 16 (17.6%) were electively delivered because of an abnormal result. There were no significant differences in labour performance or neonatal outcome between those women opting for conservative management or induction of labour. 201 new ultrasound scans were booked, 129 were performed (0.4 scans/week/1000 deliveries).