Infant feeding choices among Panamanian mothers: A qualitative study

Infant and child nutrition practices are among the most critical determinants of infant health and breastfeeding is considered the gold standard of infant feeding. Despite extensive public health interventions to promote breastfeeding, its prevalence has decreased in recent years in Panama, particularly in urban settings. There has been a nearly 20% drop in breastfeeding in the 10 years leading to 2020. Current literature often fails to elucidate the factors underpinning Panamanian mothers' decision making in relation to breastfeeding. This article explores the experiences, views, and decision making related to infant feeding choices of mothers in Panama City. The study used a qualitative approach, involving online semistructured interviews with seven participants. Utilizing the socioecological model enabled an understanding of the influence of the various, nested levels of a mother's social environment on behaviors and practices. Five themes were developed following analysis: "practical, bodily, and emotional challenges"; "workplace influences"; "family and friends' support"; "the role of health care and healthcare professionals"; "the influence of social and cultural norms on decisions and practices." The main barrier to breastfeeding was the lack of family support, especially from grandmothers. In contrast, private lactation consultation and partners' support were perceived as the best approaches for breastfeeding success, suggesting an urgent need for publicly available lactation support. This study demonstrates the importance of understanding the complexity of the social norms surrounding infant feeding, showing the challenges that mothers face in this process, and sheds light on the (public) interventions necessary to improve breastfeeding initiation and continuation.

End of life care for people with dementia: The views of health professionals, social care service managers and frontline staff on key requirements for good practice

Background

Evidence consistently shows that people with advanced dementia experience suboptimal end of life care compared to those with cancer; with increased hospitalisation, inadequate pain control and fewer palliative care interventions. Understanding the views of those service managers and frontline staff who organise and provide care is crucial in order to develop better end of life care for people with dementia.

Methods and findings

Qualitative interviews and focus groups were conducted from 2013 to 2015 with 33 service managers and 54 staff involved in frontline care, including doctors, nurses, nursing and care home managers, service development leads, senior managers/directors, care assistants and senior care assistants/team leads. All were audio recorded and transcribed verbatim. Participants represented a diverse range of service types and occupation. Transcripts were subject to coding and thematic analysis in data meetings. Analysis of the data led to the development of seven key themes: Recognising end of life (EOL) and tools to support end of life care (EOLC), Communicating with families about EOL, Collaborative working, Continuity of care, Ensuring comfort at EOL, Supporting families, Developing and supporting staff. Each is discussed in detail and comprise individual and collective views on approaches to good end of life care for people with dementia.

Conclusions

The significant challenges of providing good end of life care for people with dementia requires that different forms of expertise should be recognised and used; including the skills and knowledge of care assistants. Successfully engaging with people with dementia and family members and helping them to recognise the dying trajectory requires a supportive integration of emotional and technical expertise. The study strengthens the existing evidence base in this area and will be used with a related set of studies (on the views of other stakeholders and observations and interviews conducted in four services) to develop an evidence-based intervention.

Talking About Looking: Three Approaches to Interviewing Carers of People With Rheumatoid Arthritis About Information Seeking

Given the profusion of illness-related information, in this article, we consider how talking about information seeking-and in particular Internet use-is difficult, not because it is necessarily a highly sensitive topic (though it may be), but rather due to the unusual and unfamiliar situation of talking about information seeking. Drawing on interviews conducted as part of a study on the educational needs of carers of people with rheumatoid arthritis, we compare three types of interview for understanding online information seeking: interviews (recall), researcher-led observation (joining participant at the computer), and diaries. We discuss the strengths and weaknesses of each approach and discuss how changing interview questions and the form of interaction can help to produce different types of data, and potentially more meaningful insights. Of the three approaches, conducting interviews with participants while looking at a computer (talking while looking) offered the best opportunities to understand Internet-based information seeking.

Medical students' views about person-centred communication in dementia care

Adopting principles of person-centred communication has been highlighted as one strategy to improve care of people living with dementia (PLWD) in health and social care settings. However, person-centred communication is interpreted and applied variably in different settings, and healthcare professionals' views about communicating with PLWD are under-explored. This study aimed to investigate medical students' views about the principles and applicability of a model of person centred communication - the Dementia Model of Effective Communication (DeMEC) - to clinical practice. Quantitative and qualitative data was collected using questionnaires ( n = 531), focus groups ( n = 21) and interviews ( n = 10). Students generally endorsed the person-centred approach to communication, but two aspects were highlighted as complex and divisive - the acceptability or otherwise of lying, and of communicating with family in advance of the PLWD. We discuss the nature of these communicative dilemmas, implications for the education and training of medical students, and future directions for research.

Why is dementia different? Medical students' views about deceiving people with dementia

OBJECTIVES

Care of patients with dementia raises challenging ethical issues, including the use of deception in clinical practice. This study aimed to determine the extent to which medical students agree that ethical arguments for and against deceiving patients in general apply to patients with dementia.

METHOD

Qualitative study using six focus groups (n = 21) and 10 interviews (n = 10) with undergraduate students in years 1, 3 and 5 at a UK medical school. Analysis using initial coding followed by comparison of data with a pre-existing framework concerning deception in clinical practice.

RESULTS

Arguments for and against deceiving patients with dementia overlapped with those previously described in relation to clinical practice in general. However, the majority of participants highlighted issues unique to dementia care that warranted additional consideration. Three key dementia-specific considerations identified were capacity (understanding, retaining and emotional processing), perceived vulnerability and family dynamics. Students expressed uncertainty as to their ability to make judgements about honest communication with patients with dementia and their families.

CONCLUSION

Dementia adds additional complexity to clinical judgements about the acceptability of deception in practice. Medical students have a number of unmet learning needs with regard to communicating with patients with dementia and their families. Existing ethical frameworks may provide a helpful starting point for education about dementia care.

Expert views on the factors enabling good end of life care for people with dementia: a qualitative study

Background

Dementia, of all long term illnesses, accounts for the greatest chronic disease burden, and the number of people with age-related diseases like dementia is predicted to double by 2040. People with advanced dementia experience similar symptoms to those dying with cancer yet professional carers find prognostication difficult and struggle to meet palliative care needs, with physical symptoms undetected and untreated. While elements of good practice in this area have been identified in theory, the factors which enable such good practice to be implemented in real world practice need to be better understood. The aim of this study was to determine expert views on the key factors influencing good practice in end of life care for people with dementia.

Methods

Semi-structured telephone and face-to-face interviews with topic guide, verbatim transcription and thematic analysis. Interviews were conducted with experts in dementia care and/or palliative care in England (n = 30).

Results

Four key factors influencing good practice in end of life care for people with dementia were identified from the expert interviews: leadership and management of care, integrating clinical expertise, continuity of care, and use of guidelines.

Conclusions

The relationships between the four key factors are important. Leadership and management of care have implications for the successful implementation of guidelines, while the appropriate and timely use of clinical expertise could prevent hospitalisation and ensure continuity of care. A lack of integration across health and social care can undermine continuity of care. Further work is needed to understand how existing guidelines and tools contribute to good practice.

Disclaimer

This article presents independent research funded by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research programme (Grant Reference Number RP-PG-0611-20005). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health.

Evidence-based evolution of the high stakes postgraduate intensive care examination in Australia and New Zealand

The fellowship examination for intensive care medicine in Australia and New Zealand, first held in 1979, has undergone four major periods of development and change since inception. These periods are characterised as: 1. 1979 to 1996--initiation and establishment of the exam as a relevant and comprehensive assessment process for a new specialty. 2. 1997 to 2001--revision to increase breadth of coverage, increase reliability for a growing number of candidates and ensure that each candidate received the same exam: Expansion: to incorporate assessment of CanMEDS skills (including communication, procedures and professional qualities). Lengthening: to increase the number of exposures, to ensure reliability. Quarantining of candidates: to allow the provision of a similar exam for each candidate. 3. 2002 to 2006--increasing emphasis on examiner training, standard setting and increasing feedback to candidates to improve the educational experience and guide exam preparation. Blueprinting of questions to maintain validity. 4. 2008 onwards--logistic revision to ensure feasibility for a rapidly growing number of candidates and refinement to apply modem standard setting and quality control. The exam has been regarded as a 'tough but fair' assessment in its 30 years of existence and the committee overseeing its development has aimed to continually review the process to maintain those qualities as well as reliability, validity and feasibility. The increasing number of candidates has allowed accumulation of usable statistics but has tested the feasibility of running such a labour intensive exam. To date, there have been 800 presentations to the exam with 498 successful candidates.

The Effects of Salivary Gland Extracts from Boophilus microplus Ticks on Mitogen-stimulated Bovine Lymphocytes

The effect of salivary gland extract (SGE) from the tick Boophilus microplus was examined in mitogen-stimulated lymphocytes in vitro. SGE was added to lymphocytes of seven cattle together with the mitogens concanavalin A (ConA), phytohaemagglutinin (PHA) and pokeweed mitogen (PWM). Semi-purified B cells from another seven cattle were stimulated with the mitogen lipopolysaccharide (LPS). PHA and ConA stimulated proliferation of lymphocytes to the same extent, but the inhibition due to SGE of Boophilus microplus on the proliferative response stimulated by PHA (39.0% +/- 9.3%) was less than the inhibition of proliferative response stimulated by ConA (75.4% +/- 6.9%). In contrast, SGE of B. microplus stimulated the proliferation of B cells in the presence of LPS in a dose-dependent manner. Enhanced stimulation of B cells by SGE at >4 microg in culture was greater than twice that observed when B cells were stimulated by LPS alone. SGE does not have a direct suppressive effect on bovine B cell proliferation; however, in vivo the effectiveness of B cell responses might be influenced by other immune factors, such as cytokine profiles.

The relationship between hypertension and anxiety or depression in Hong Kong Chinese

BACKGROUND

Psychosocial stress can be the cause or the consequence of hypertension.

OBJECTIVE

To study the association between hypertension and anxiety or depression in adults from Hong Kong, China.

SUBJECTS AND METHODS

Patients with diagnosed hypertension (n=197) were recruited to complete the Hospital Anxiety and Depression Scale (HADS) questionnaire. The control group comprised 182 normotensive subjects recruited using random telephone numbers.

RESULTS

The score in the anxiety subscale (HADS-A) of the HADS correlated with age (r= -0.23, P<0.001) and sex (r=0.11, P=0.042), and was found to be higher in women. The score in the depression subscale (HADS-D) correlated with age (r=0.17, P=0.003) and hypertension (r=0.12, P=0.039), but not with sex (r=0.02, P=0.68). When the control subjects were matched for sex and age with the subjects with hypertension, the mean HADS-A score was 5.51+/-0.41 in 113 hypertensive subjects and 4.38+/-0.39 in 113 normotensive subjects (P=0.047). The mean HADS-D score was 5.56+/-0.39 in the hypertensive and 4.76+/-0.32 in the normotensive subjects (P=0.11). Multiple regression analysis using data from both groups indicated that the HADS-A score was related to the HADS-D score (beta=0.49, P<0.001), age (beta= -0.25, P<0.001) and sex (beta=0.12, P=0.01) (R(2)=0.28), whereas the HADS-D score was related to the HADS-A score (beta=0.48, P<0.001), age (beta=0.30, P<0.001), positive smoking status (beta=0.13, P=0.004) and lack of exercise habit (beta=0.12, P=0.008) (R(2)=0.31). Hypertension was related to waist circumference, history of parental hypertension and age (R(2)=0.38, P<0.001). Anxiety and depression scores were rejected as independent variables.

CONCLUSIONS

Hypertension was associated with anxiety but not depression; however, age, history of parental hypertension and central obesity appeared to have a stronger association with hypertension in adults from Hong Kong.

A comparison of the immunosuppressive effects of salivary gland extracts from two laboratory strains of Boophilus microplus

This study addresses three questions related to the immune response of cattle to tick salivary gland extracts. Firstly, is there a difference in the inhibition of proliferation of Concanavalin A (ConA) stimulated bovine lymphocytes induced by salivary gland extracts of the N and Y strains of Boophilus microplus? Second, is there a difference in the development rate of the Y and N tick strains? Third, does the host affect the inhibitory effect of salivary gland extract on the proliferation of ConA stimulated lymphocytes from the two tick strains? Salivary gland extract of the Y strain inhibited in vitro proliferation of lymphocytes stimulated by ConA significantly more than that of the N strain, when each strain was raised on different animals. A difference in the development rate was observed between the tick strains when raised on the same animal, with female ticks of the Y strain developing faster and reaching a greater fully engorged weight than ticks of the N strain. The difference in their rate of development did not appear to contribute to a difference in inhibitory effects of the salivary gland extracts and there was no difference between the inhibitory effects of salivary gland extracts from both strains. However, when Y strain ticks were raised on different animals, there was a significant difference in the inhibition of lymphocyte proliferation between the two salivary gland extracts. Therefore, it was concluded that there is no difference between the inhibitory effects of the two tick strains and that the host has an influence on salivary gland extract composition of B. microplus and its inhibitive properties.

Early invasive revascularisation for patients critically ill after acute myocardial infarction: impact on outcome and ICU resource utilisation

OBJECTIVE

To assess the value of early invasive revascularization for the initial management of critically ill patients after acute myocardial infarction in the daily practice of a University-affiliated referral hospital and to gauge the impact of such a strategy on the intensive care unit.

PATIENTS AND METHODS

A prospective observational study on all patients admitted to the Royal North Shore hospital who had acute pulmonary oedema and/or shock prior to acute angiography for acute myocardial infarction from January 1(st), 1998 to December 31, 2001.

RESULTS

During the study period 846 patients with acute myocardial infarction had coronary artery angiography, 139 had acute pulmonary oedema and/or shock prior to angiography. The average age was 70 years, 65% of whom were male. Approximately 70% of these patients were admitted to the intensive care unit and coronary artery bypass surgery was performed on 38%. Of those patients admitted to the intensive care unit, 95% required mechanical ventilation, 81% required inotropic support and 50% required intra-aortic Balloon counterpulsation. In-hospital mortality was 32%, 6 weeks mortality was 38% and 6 month mortality was 42%.

CONCLUSIONS

Our results confirm the benefit of early invasive revascularisation for critically ill patients after acute myocardial infarction although a substantial amount of intensive care unit resources and cardiothoracic surgical expertise were required.

Pathological and immunological changes after challenge infection with Pasteurella multocida in naive and immunized calves

Challenge infections of calves with Pasteurella multocida were established to characterize the local inflammatory response and determine the effect of previous exposure to live bacteria on the post-challenge immune response. Experimental infections were established by intratracheal inoculation of P. multocida in both naive calves and calves that had been previously vaccinated with two subcutaneous (s.c.) injections of live bacteria. Histological, immunohistological and cytokine expression studies were performed on bronchoalveolar lavage (BAL) samples, lung parenchymal tissues and lung lymph nodes (LN). In comparison to uninfected control animals in which no lung lesions were observed, a patchy to confluent bronchopneumonia was observed following infection of naive calves, characterized by abscess formation, haemorrhage, oedema and suppurative consolidation. Cellular analysis following infection of naive animals was characterized by an influx of neutrophils in the BAL, with macrophages and dendritic cells observed in the lesion perimeter. A significant increase in the number of CD8(+) blasts expressing MHC (major histocompatibility) II was also observed in the BAL of infected calves. Decreased expression of interleukin (IL)-1 beta and increased expression of IL-8 compared to naive unchallenged controls was apparent in lung LN. In comparison, a more limited pathology was observed in vaccinated animals post-challenge, indicating partial protection conferred by the s.c. immunization with live bacteria. Studies of vaccinated animals showed the presence of bronchial-associated lymphoid tissue (BALT) in the lung tissue and an increase in the number of B-cells and CD4(+) T-cells expressing MHCII in the lung LN after challenge. In contrast to primary infection, there was no significant influx of neutrophils in the BAL. Instead, a population of newly recruited monocytes/macrophages was observed. Increased IL-2 expression and decreased IL-8 expression was observed in the LN, while IL-1 beta expression was not detected. The reduced neutrophil and increase monocyte response in the vaccinated calves may be associated with significant changes in the gamma delta T lymphocyte population in the BAL.

The protective effect of niacinamide on ischemia-reperfusion-induced liver injury

Reperfusion of ischemic liver results in the generation of oxygen radicals, nitric oxide (NO) and their reaction product peroxynitrite, all of which may cause strand breaks in DNA, which activate the nuclear enzyme poly(ADP ribose)synthase (PARS). This results in rapid depletion of intracellular nicotinamide adenine dinucleotide and adenosine 5'-triphosphate (ATP) and eventually induces irreversible cytotoxicity. In this study, we demonstrated that niacinamide, a PARS inhibitor, attenuated ischemia/reperfusion (I/R)-induced liver injury. Ischemia was induced by clamping the common hepatic artery and portal vein of rats for 40 min. Thereafter, flow was restored and the liver was reperfused for 90 min. Blood samples collected prior to I and after R were analyzed for methyl guanidine (MG), NO, tumor necrosis factor (TNF-alpha) and ATP. Blood levels of aspartate transferase (AST), alanine transferase (ALT) and lactate dehydrogenase (LDH) which served as indexes of liver injury were measured. This protocol resulted in elevation of the blood NO level (p < 0.01). Inflammation was apparent, as TNF-alpha and MG levels were significantly increased (p < 0.05 and p < 0.001). AST, ALT and LDH were elevated 4- to 5-fold (p < 0.001), while ATP was significantly diminished (p < 0.01). After administration of niacinamide (10 mM), liver injury was significantly attenuated, while blood ATP content was reversed. In addition, MG, TNF-alpha and NO release was attenuated. These results indicate that niacinamide, presumably by acting with multiple functions, exerts potent anti-inflammatory effects in I/R-induced liver injury.

The protective effect of niacinamide on ischemia-reperfusion-induced liver injury

Reperfusion of ischemic liver results in the generation of oxygen radicals, nitric oxide (NO) and their reaction product peroxynitrite, all of which may cause strand breaks in DNA, which activate the nuclear enzyme poly(ADP ribose)synthase (PARS). This results in rapid depletion of intracellular nicotinamide adenine dinucleotide and adenosine 5'-triphosphate (ATP) and eventually induces irreversible cytotoxicity. In this study, we demonstrated that niacinamide, a PARS inhibitor, attenuated ischemia/reperfusion (I/R)-induced liver injury. Ischemia was induced by clamping the common hepatic artery and portal vein of rats for 40 min. Thereafter, flow was restored and the liver was reperfused for 90 min. Blood samples collected prior to I and after R were analyzed for methyl guanidine (MG), NO, tumor necrosis factor (TNF-alpha) and ATP. Blood levels of aspartate transferase (AST), alanine transferase (ALT) and lactate dehydrogenase (LDH) which served as indexes of liver injury were measured. This protocol resulted in elevation of the blood NO level (p < 0.01). Inflammation was apparent, as TNF-alpha and MG levels were significantly increased (p < 0.05 and p < 0.001). AST, ALT and LDH were elevated 4- to 5-fold (p < 0.001), while ATP was significantly diminished (p < 0.01). After administration of niacinamide (10 mM), liver injury was significantly attenuated, while blood ATP content was reversed. In addition, MG, TNF-alpha and NO release was attenuated. These results indicate that niacinamide, presumably by acting with multiple functions, exerts potent anti-inflammatory effects in I/R-induced liver injury.

The lung is the major site that produces nitric oxide to induce acute pulmonary oedema in endotoxin shock

1. The present study was undertaken to determine the locus of nitric oxide (NO) production that is toxic to the lung and produces acute pulmonary oedema in endotoxin shock, to examine and compare the effects of changes in lung perfusate on endotoxin-induced pulmonary oedema (EPE) and to evaluate the involvement of constitutive and inducible NO synthase (cNOS and iNOS, respectively). 2. Experiments were designed to induce septic shock in anaesthetized rats with the administration of Escherichia coli lipopolysaccharide (LPS). Exhaled NO, lung weight (LW)/bodyweight (BW) ratio, LW gain (LWG) and lung histology were measured and observed to determine the degree of EPE 4 h following LPS. The EPE was compared between groups in which LPS had been injected either into the systemic circulation or into the isolated perfused lung. The lung perfusate was altered from whole blood to physiological saline solution (PSS) with 6% albumin to test whether different lung perfusions affected EPE. Pretreatment with various NOS inhibitors was undertaken 10 min before LPS to investigate the contribution of cNOS and iNOS to the observed effects. 3. Endotoxin caused profound systemic hypotension, but little change in pulmonary arterial pressure. The extent of EPE was not different between that induced by systemic injection and that following administration to isolated lungs preparations. Replacement of whole blood with PSS greatly attenuated (P < 0.05) EPE. In blood-perfused lungs, pretreatment with NOS inhibitors, such as Nomega-nitro-L-arginine methyl ester, aminoguanidine and dexamethasone, significantly prevented EPE (P < 0.05). 4. The major site of NO production through the whole blood is in the lung. The NO production mediated by the iNOS system is toxic to the endothelium in the pulmonary microvasculature. Inhalation of NO for patients with sepsis may be used with clinical caution. Therapeutic consideration of lung extracorporeal perfusion with PSS and pharmacological pretreatment with iNOS inhibitors may be warranted.

Involvement of CYP2E1 and carboxylesterase enzymes in vinyl carbamate metabolism in human lung microsomes

Previous studies have shown that CYP2E1 and carboxylesterase enzymes contributed to vinyl carbamate (VC) metabolism in murine lung. Moreover, these studies have implicated CYP2E1 and the carboxylesterases in bioactivation and detoxication, respectively. Here we have tested the hypothesis that CYP2E1 and carboxylesterase enzymes are involved also in VC metabolism in human lung. Demethylation of N-nitrosodimethylamine (NDMA) is an enzyme activity associated with CYP2E1, and was used as a catalytic marker for this P450 in human lung microsomes. NDMA demethylase activity in lung microsomes from 10 patients ranged from 36.9 +/- 1.0 to 82.4 +/- 2.4 pmol/mg protein/min. Significant decreases (40-65%) in demethylase activity were detected in lung microsomes incubated with VC and NADPH, compared with the controls in which incubations were performed with only VC or only NADPH. Preincubation with the CYP2E1 inhibitor diallyl sulfone also significantly decreased demethylase activity, and abrogated the VC-induced effect. Similarly, preincubation of lung microsomes with a human CYP2E1 inhibitory monoclonal antibody ameliorated the VC-induced reduction in demethylase activity. Microsomal carboxylesterase activity in lung microsomes from 10 patients ranged from 19.02 +/- 2.28 to 48.18 +/- 4.34 nmol/mg protein/min, and was significantly decreased (25-45%) in microsomes incubated with phenylmethylsulfonyl fluoride, an inhibitor of the carboxylesterase enzyme. Preincubation of lung microsomes with phenylmethylsulfonyl fluoride and subsequent incubation with VC and NADPH exacerbated the reduction (60-80%) in demethylase activity evoked by reaction with VC and NADPH. These results are consistent with a role for the CYP2E1 enzyme and microsomal carboxylesterases in VC metabolism.

Elevated anti-parasitic activity in peripheral blood monocytes and neutrophils of cattle infected with Babesia bovis

The innate immune response to bovine Babesia bovis infection in vivo has not previously been established. We used assays measuring phagocytosis and oxidative burst to investigate the immune response because they are indicative of the innate antimicrobial capacity of monocytes and neutrophils. Monocyte and neutrophil phagocytosis is thought to be non-specific in nature and so the phagocytosis of either opsonised Zymosan or Escherichia coli was used to indicate the non-specific phagocytic capacity of monocytes and neutrophils ex vivo. The kinetics of both phagocytic and oxidative burst activity in monocytes and neutrophils were followed twice weekly from pre-inoculation (day 0) through to 31 days after inoculation. Peripheral blood monocytes were found to display a pronounced oxidative burst, but a suppressed capacity to phagocytose during a primary infection. On the other hand, neutrophils exhibited an increased phagocytic capacity and reduced oxidative activity during a primary infection. These findings identified considerable antimicrobial activity evident in peripheral blood monocytes and neutrophils from cattle exposed to B. bovis as a primary exposure. This elevated antimicrobial activity was coincident with the time that parasite numbers peaked in the circulation and occurred prior to parasite clearance. These results suggest that peripheral blood monocytes and neutrophils are active mediators in the innate immune response to a primary B. bovis.

Opposition of rapid baroreceptor resetting by prostanoids in rabbits

Arterial baroreceptors reset rapidly within minutes during acute hypertension; baroreceptor pressure threshold (Pth) is increased and the pressure-baroreceptor activity relation is shifted to the right. The purpose of the present study was to determine if prostacyclin (PGI2) or other prostanoids, released during acute hypertension modulate the magnitude of baroreceptor resetting. Baroreceptor activity was recorded from the vascularly-isolated carotid sinus during distension of the sinus with slow pressure ramp in rabbits anesthetized with chloralose. Pressure-activity curves were generated after holding carotid sinus pressure for 10-15 min from 30 to 100 mmHg. In control, the elevation of holding pressure increased Pth from 44+/- to 65+/-5 mmHg (p < 0.05, n = 12). In the presence of PGI2 (20 microM), Pth averaged 43+/-4 and 45+/-3 mmHg (n = 12) after holding pressure at 30 and 100 mmHg, respectively. In the control group before exposing the carotid sinus to indomethacin, an elevation of holding pressure increased Pth from 49+/-2 to 71+/-3 mmHg (p < 0.05, n = 12). After inhibition of the endogenous formation of prostanoids with indomethacin (20 microM), Pth increased by a significantly greater extent from 61+/-2 to 90+/-3 mmHg (p < 0.05, n = 12) with the increase in holding pressure. The slope of the pressure-activity curve (baroreceptor gain) was not influenced by the change in holding pressure. It was increased significantly by PGI2, while decreased by indomethacin. Neither the change in holding pressure nor PGI2 affected the circumferential wall strain of carotid sinus over a wide range of pressure alteration. The results suggest that PGI2 or other prostanoids released during acute hypertension sensitizes baroreceptors and provides a negative feedback mechanism that opposes and limits the magnitude of rapid baroreceptor resetting.

Putative salivary allergens of the cat flea, Ctenocephalides felis felis

The cat flea, Ctenocephalides felis felis, is the major initiator of flea bite hypersensitivity in dogs. Previous analyses of whole extracts of the flea and flea salivary secretions have failed to identify the allergens responsible. We dissected >2000 salivary glands from adult female fleas, extracted them into buffered saline containing protease inhibitors and fractionated the extract using gel permeation HPLC. Dogs were classified as hypersensitive to fleas (flea-feeding positive, FF+) or insensitive (flea-feeding negative, FF-) using a provocative test with live fleas. The allergenicity of the components of the salivary gland extract was tested by intradermal injection of samples of the column eluates. Dogs were also injected intradermally with a sample of whole salivary gland extract, and with histamine as a positive control. Negative control injections consisted of eluate from the column collected prior to fractions containing any protein. The skin of FF- dogs either did not respond or had a minimal response (a bleb approximately 2 mm larger than the injection blebs at the negative control injection sites) to all fractions and to the whole extract; histamine control injections produced positive responses (defined as wheals 5 mm greater than the blebs at the negative control injection sites) in all dogs. The skin of three of the nine FF+ dogs reacted positively to injection of a fraction containing protein/s with apparent MW 40k. Five other FF+ dogs reacted positively to the fractions containing proteins with apparent MW 12-8k. A single dog responded with very large, red wheals to injection of both the approximately MW 40k and MW12-8k fractions. These findings suggest that proteins with apparent MW 40k and MW 12k-8k are important in flea bite hypersensitivity. This work also supports a previous finding that mice which had been exposed to flea bites had antibodies to proteins with approximately MW 40k that were detected in salivary secretions of the flea.

Detection and measurement of canine alpha-macroglobulins by enzyme immuno-assay

The alpha-macroglobulins are broad-specificity protease inhibitors important in the regulation and clearance from circulation of biologically active proteases. Inappropriate protease activation may be a feature of canine acute pancreatitis and the ability of the animal to clear these proteases may be important in determining survival. An enzyme immunoassay for the detection and measurement of canine alpha-macroglobulins in plasma samples was developed. A reference range for the canine alpha-macroglobulins of 1.20-2.72 mg ml-1 was established from a panel of canine plasma samples, and the stability of the alpha-macroglobulins in plasma samples stored at 4 degrees C was investigated. Changes in the level of the alpha-macroglobulins during disease states involving increased endogenous protease activity can now be investigated using a rapid, repeatable and quantifiable assay.

Anti-immunoglobulin antisera used in an ELISA to detect antibodies in barramundi Lates calcarifer to Cryptocaryon irritans

Immunoglobulins (Ig) in serum from barramundi vaccinated with bovine serum albumin (BSA) were purified by ammonium sulphate precipitation and affinity chromatography using BSA as the ligand. The BSA-binding activity of eluted putative Ig fractions was assessed by enzyme-linked immunosorbent assay (ELISA) before being pooled and characterised by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Double affinity purification did not improve the purity of the Ig preparation compared to single affinity purification. Barramundi Ig were injected into sheep to produce anti-Ig antisera which were assessed in an indirect ELISA as the secondary antibody to detect serum Ig in barramundi vaccinated with Cryptocaryon irritans theronts. Affinity-purified Ig induced a more specific reagent for use as secondary antibody in ELISA than did normal whole-barramundi sera. The heavy (H) chain of barramundi Ig had an apparent molecular weight of 70 kDa while that of the light (L) chain was 27 kDa in SDS-PAGE studies. Under non-reducing conditions 2 putative populations of Ig were identified, at 768 and 210 kDa. The N-terminal sequence of the barramundi Ig H chain showed 78% homology with channel catfish Ictalurus punctatus Ig H chain sequence.

Inactivation of cytochrome P-450 (CYP2E1) and carboxylesterase (hydrolase A) enzymes by vinyl carbamate in murine pulmonary microsomes

We tested the hypothesis that vinyl carbamate (VC) is metabolized in vitro by cytochrome P-450 and carboxylesterase enzymes in murine lung. Incubations with VC and an NADPH-generating system produced a 50% decrease in N-nitrosodimethylamine (NDMA) demethylation and a corresponding loss in the amounts of immunodetectable CYP2E1. Preincubation of microsomes with a CYP2E1 inhibitory antibody or the CYP2E1-selective inhibitor diallyl sulfone (DASO2) inhibited demethylase activity; no alterations were detected upon subsequent exposure to VC. Carboxylesterase-mediated hydrolysis of p-nitrophenyl acetate was reduced by 22% in microsomes incubated with VC. Decreased carboxylesterase activity also was detected in microsomes incubated with phenylmethylsulfonyl fluoride (PMSF), an inhibitor of hydrolase A, a carboxylesterase isozyme. No change in enzyme activity was detected when microsomes were subsequently incubated with VC. The loss in carboxylesterase activity correlated with decreased immunodetectable hydrolase A in microsomes incubated with VC, PMSF, or PMSF and VC. The reduction in VC-induced NDMA demethylase activity was increased to 85% of the control in microsomes previously incubated with PMSF, and this corresponded with a marked decrease in CYP2E1 immunoreactivity in the immunoblots. Covalent binding of VC to proteins was detected in microsomes incubated with VC and an NADPH-generating system. Binding was inhibited in microsomes preincubated with either an inhibitory CYP2E1 antibody or DASO2. In contrast, binding levels were augmented in microsomes preincubated with PMSF. These data supported VC metabolism by CYP2E1 and hydrolase A in murine lung microsomes and is consistent with involvement of CYP2E1 and hydrolase A in the activation and detoxication of VC, respectively.

Sustained-release delivery systems and their application for endoparasite control in animals

A solid formulation of a potent anthelmintic macrocyclic lactone, moxidectin, was administered using a non-degradable delivery device to discharge the agent into the subcutaneous tissues of sheep. In vivo release was monitored in sheep indirectly using faecal egg counts. Using a dose of 0.2 mg moxidectin/kg body weight when applied in the form of a solid pellet, protection of sheep against Haemonchus contortus challenge was conferred to a level greater than that of sheep which received Cydectin, the commercial liquid injectable form delivered at the same dosage. The anthelmintic efficacy of the solid formulation was assessed at four dosage levels in sheep and it was demonstrated that the dosage of anthelmintic agent could be reduced to 1/6 of the present recommended injectable dose. When two pellets containing the recommended dose of moxidectin were loaded into a non-degradable delivery device, the period of H. contortus control was extended from 42 to 183 days. Antibody levels of sheep receiving repeated infections of H. contortus L3 larvae and treated with moxidectin-loaded devices were reduced significantly compared to the levels observed in sheep treated with Cydectin (p < 0.0005). This implies that the group treated with the moxidectin-loaded devices was exposed to a reduced antigenic load compared to sheep treated with placebo devices, and sheep treated with Cydectin. The antibody levels generated in the sheep treated with placebo devices were no different to those treated with Cydectin. Application of this sustained release device may allow the control of nematode diseases in livestock throughout an entire season with a single administration.

Isozyme-selective metabolism of ethyl carbamate by cytochrome P450 (CYP2E1) and carboxylesterase (hydrolase A) enzymes in murine liver microsomes

Cytochrome P450 and carboxylesterase enzymes have been implicated in the metabolism of the carcinogen ethyl carbamate (EC). In this study, we have used a murine liver microsomal system to investigate the relative contributions of P450 and carboxylesterase isozymes to hepatic metabolism of EC. N-Nitrosodimethylamine (NDMA) demethylation and p-nitrophenyl acetate (PNA) hydrolysis were used as catalytic markers of CYP2E1 and carboxylesterase enzymes, respectively. Incubation of liver microsomes with EC (1 mM) produced slight but significant decreases in NDMA demethylation and PNA hydrolysis activities. Incubation of microsomes with paraoxon (PAX), a general carboxylesterase inhibitor, or phenylmethylsulfonyl fluoride (PMSF), a specific inhibitor of hydrolase A, produced decreases of 85 and 45%, respectively, in carboxylesterase activities; neither of the inhibitors elicited alterations in levels of NDMA demethylation. Reaction of microsomes with either PAX or PMSF and then with EC exacerbated the reduction (285%) of NDMA demethylation, and this loss corresponded to decreases in immunodetectable CYP2E1 content. The reduction in PNA hydrolysis activity induced by PAX, PMSF, or EC correlated with decreased immunodetectable hydrolase A in liver microsomes; however, reaction with PAX and not PMSF or EC resulted in loss of immunoreactivity for hydrolase B. These data correlated with levels of covalent binding of [ethyl-14C]EC to liver microsomes, which were significantly elevated in incubations conducted with PAX or PMSF. Antibody inhibition of the CYP2E1 enzyme significantly reduced levels of binding to microsomal proteins, compared with control levels. These results are consistent with the premise that EC is metabolized by CYP2E1 and hydrolase A in liver microsomes of mice.

Metabolism of ethyl carbamate by pulmonary cytochrome P450 and carboxylesterase isozymes: involvement of CYP2E1 and hydrolase A

The lung is highly susceptible to ethyl carbamate (EC)-induced tumorigenesis. Our goal in this study was to investigate the in vitro isozyme-selective metabolism of EC in lung microsomes by cytochrome P450 and carboxylesterase enzymes. Our results showed that incubations with EC produced significant reduction in p-nitrophenol (PNP) hydroxylation and N-nitrosodimethylamine (NDMA) demethylation; there were no alterations in 7-pentoxyresorufin- and 7-ethoxyresorufin O-dealkylase activities. Reaction of microsomes with an inhibitory CYP2E1 antibody and subsequent reaction with EC abolished the EC-induced diminution in NDMA demethylase activity. Carboxylesterase activity, as assessed by hydrolysis of p-nitrophenyl acetate, was significantly decreased in microsomes incubated with EC. Reactions with EC in conjunction with the carboxylesterase inhibitors, paraoxon (PAX) or phenylmethylsulfonyl fluoride (PMSF), abolished the EC-induced decrease in carboxylesterase activity; PAX is a broad-spectrum carboxylesterase inhibitor, whereas PMSF is a specific inhibitor of hydrolase A, a carboxylesterase isozyme. Incubations of EC in combination with either PAX or PMSF exacerbated the EC-induced reduction in PNP hydroxylase and NDMA demethylase activities. Alterations in immunodetectable CYP2E1 protein levels were not apparent in microsomes incubated with EC alone, but the amounts were decreased in reactions with EC in conjunction with either PAX or PMSF. Immunoblotting with antibodies for the carboxylesterase isozymes, hydrolase A and B, revealed loss of immunodetectable hydrolase A in microsomes incubated with EC, PAX, or PMSF. However, immunodetectable hydrolase B was only decreased in microsomes reacted with PAX but not with PMSF or EC. These findings correlated with our covalent binding data, which showed that levels of binding of [14C-ethyl]EC to lung microsomes were significantly higher in incubations conducted in conjunction with PAX or PMSF, compared with control levels. Antibody inhibition of the CYP2E1 enzyme significantly reduced the extent of binding. Our results demonstrated that EC metabolism in lung microsomes, as estimated from magnitudes of covalent binding, is mediated by the P450 isozyme CYP2E1 and the carboxylesterase isozyme hydrolase A.

Characterization of cytokine profiles and double-positive lymphocyte subpopulations in normal bovine lungs

OBJECTIVE

To characterize cytokine profiles and lymphocyte subpopulations in lung parenchyma and bronchoalveolar lavage (BAL) fluid from normal bovine lungs.

ANIMALS

Eight 12- to 18-month-old cattle.

PROCEDURE

Cell populations in BAL fluid and collagenase-digested lung parenchyma were analyzed by flow cytometry and monoclonal antibodies. Proportions of total cell populations were determined, using Giemsa-stained cytospots. Distribution of lymphocytes within the lung parenchyma was analyzed by immunohistochemistry, and cytokine mRNA species in the parenchyma were characterized by use of reverse transcriptase-polymerase chain reaction analysis.

RESULTS

Cytokine profiles indicated high amounts of mRNA for interleukins 6 and 10 and transforming growth factor beta. In the BAL fluid and lung parenchyma, macrophages were the predominant cell type, although the proportion was lower in the parenchyma. Lymphocytes made up approximately 3% of both cell populations. Common to both lung compartments was the predominance of CD2+ and gamma delta T cells over B lymphocytes. There were more CD8+ T cells than CD4+ T cells in both compartments. The gamma delta cells made up approximately 9% of the lymphocyte populations. Two-color flow cytometry revealed CD8+ gamma delta T cell and CD8+CD5- populations that were unique to BAL fluid. In the BAL fluid and parenchyma, most CD4+ and CD8+ T cells expressed high amounts of CD44, a characteristic of memory T cells. The gamma delta T cells were CD44(10), as were B cells in the lung parenchyma. The B cells from BAL fluid expressed high amounts of CD44. Immunohistologic analysis of lung tissue revealed bronchus-associated lymphoid tissue structures with distinctive germinal center organization of B cells encompassed by CD4+ T cells.

CONCLUSIONS

Results provided normal values for comparison with those of other species and with the bovine respiratory tract response to disease.

Differential formation of 1,1-dichloroethylene-metabolites in the lungs of adult and weanling male and female mice: correlation with severities of bronchiolar cytotoxicity

The bronchiolar Clara cell cytotoxicant, 1,1-dichloroethylene (DCE), is selectively metabolized by CYP2E1 to metabolites including 2,2-dichloroacetaldehyde and DCE-epoxide. We have performed comparative studies in the lungs of adult and weanling male and female mice to determine their relative capacities to metabolize DCE. Levels of activities of p-nitrophenol hydroxylase, N-nitrosodimethylamine demethylase and NADPH-cytochrome P450 reductase were all significantly higher in adult female mice than in either adult male or weanling mice of both sexes. The quantities of 2,2-dichloroacetaldehyde (identified as its hydrolysis product, acetal) and the DCE-epoxide (identified as the GSH conjugates, 2-(S-glutathionyl) acetyl glutathione [B] and 2-S-glutathionyl acetate [C]) formed were significantly higher in lung microsomes from adult female mice than in those from either adult male or weanling mice of both sexes. Also, the metabolite levels formed in weanling mice were significantly higher than in adult male mice. The amounts of DCE-metabolites produced correlated with the relative severities of DCE-induced bronchiolar damage. The severities of bronchiolar injury were in the rank order adult female > weanling male and female > adult male mice, and coincided with the rank order of DCE-epoxide formation in these experimental groups of mice. In comparison with adult male and weanling male and female mice, adult female mice expressed highest levels of activities of CYP2E1-selective and reductase enzymes, formed most of the DCE-epoxide and were most susceptible to DCE-induced pneumotoxicity. These findings demonstrated sex-related differences in expression of activating enzymes and DCE metabolism in lung, and only in the adult female vs. female weanling mice were there age-related effects in regard to formation of both DCE-metabolites and cytotoxicity.

Purification of hydrophobic integral membrane proteins from Mycoplasma hyopneumoniae by reversed-phase high-performance liquid chromatography

A general and practical approach for isolating, fractionating and purifying large quantities of outer membrane hydrophobic proteins is described as applied to membrane proteins of Mycoplasma hyopneumoniae. Outer membrane proteins were extracted with Triton X-114 detergent and were precipitated from the detergent phase with 90% ethanol. Precipitated proteins were dissolved in 65% formic acid and separated by RP-HPLC using a formic acid-acetonitrile gradient. A M(r) 48 000 protein was obtained in high yield and at greater than 90% purity by optimisation of parameters for RP-HPLC. The combination of Triton X-114 extraction followed by high resolution RP-HPLC is a novel and rapid procedure for the isolation and purification of hydrophobic proteins. Proteins purified by this approach were suitable for subsequent characterisation by direct sequencing of the amino terminus as well as generation of peptides by digestion with cyanogen bromide.

Protection from 1,1-dichloroethylene-induced Clara cell injury by diallyl sulfone, a derivative of garlic

Bronchiolar Clara cell damage ensues after treatment of mice with 1,1-dichloroethylene (DCE). The cytotoxicity is mediated by CYP2E1, a cytochrome P450 isozyme that is highly localized in the Clara cells. Bioactivation of DCE produces the primary metabolites 2,2-dichloroacetaldehyde, which hydrolyzes to the acetal, and DCE epoxide, which reacts with glutathione to form the conjugates 2-(S-glutathionyl) acetyl glutathione [B] and 2-S-glutathionyl acetate [C]. In this study, we investigated the potential of diallyl sulfone (DASO2) to inhibit CYP2E1, to suppress the bioactivation of DCE to reactive intermediates and to abrogate DCE-induced Clara cell cytotoxicity. Our results showed that treatment of mice with DASO2 (100 mg/kg p.o.) produced decreases in CYP2E1-dependent p-nitrophenol hydroxylation that were apparent at 1 h. Enzyme activity plummeted to about 20% of the control by 2 h and remained at this low level from 3 to 8 h. Recovery of activity was evident at 16 h and returned to the control level by 24 h. Immunoreactivity of the CYP2E1 protein was decreased in immunoblots of lung microsomes from DASO2-treated mice. Treatment with DASO2 did not cause any structural alterations in lung tissue; in contrast, treatment with DCE (75 mg/kg) produced Clara cell damage. This lesion was not manifested in mice treated with DASO2 in conjunction with DCE. The lack of cytotoxicity observed in vivo correlated with a reduction of about 45% in the levels of both the acetal and the DCE epoxide-derived conjugates [B] and [C] in vitro. These results demonstrated that DASO2 significantly inhibited the CYP2E1 enzyme, decreased the production of DCE metabolites and protected Clara cells from DCE-induced cytotoxicity.

Predictors of mortality in severe malaria: a two year experience in a non-endemic area

Management of severe malaria is an increasing problem worldwide. This paper reviews the pathophysiology and management documenting two years' experience of admissions of severe malaria to an ICU in a non-endemic area. Clinical and laboratory features of severe malaria were analysed for predictors of mortality Twenty-eight patients had clinical or laboratory features compatible with the WHO criteria for severe malaria and, despite treatment with intravenous quinine and supportive ICU care, mortality was 28.5% (8/28). The three pregnant patients died with 100% foetal mortality and the four paediatric patients survived. Of the non-survivors, 8/8 developed ARDS (defined by worst ALI score > 2.5), 7/8 developed shock requiring inotropic support and 7/8 developed acute renal failure requiring CVVHD. Admission haemoglobin, platelet count, parasite count, and lowest Glasgow Coma Score in the first 24 hours were shown not to be predictors of mortality.

Pulmonary CYP2E1 bioactivates 1,1-dichloroethylene in male and female mice

Pulmonary cytotoxicity induced by 1,1-dichloroethylene (DCE) has been linked to the generation of reactive intermediates through a cytochrome P450-dependent pathway. In the present studies, our objectives were to investigate and compare cytochrome P450 isozyme-selective bioactivation of DCE in vitro in the lungs of male and female mice. Our results showed that CYP2E1-dependent p-nitrophenol hydroxylation was significantly higher in microsomes from female (0.45 +/- 0.01 nmol/mg protein/min) than from male (0.38 +/- 0.02 nmol/mg protein/min) mice. Lung microsomes from male mice incubated in the presence of an NADPH-generating system and increasing amounts of DCE (5-20 mM) exhibited corresponding decreases in p-nitrophenol hydroxylase activity (19%-50%); however, greater decreases (26%-70%) were observed in lung microsomes from female mice incubated under the same conditions. In contrast, alterations in CYP2B1-dependent 7-pentoxyresorufin O-dealkylation and CYP1A1-dependent 7-ethoxyresorufin O-dealkylation were not detected in any microsomal preparation incubated with DCE. Reaction with an anti-CYP2E1 antibody abolished the inhibition of p-nitrophenol hydroxylation by DCE. Protein immunoblotting revealed significant decreases in the intensity of the bands of microsomal samples incubated previously with DCE; in contrast, alterations in heme content were not evoked by reaction with DCE. Our results have demonstrated that CYP2E1, and not CYP2B1 or CYP1A1, mediated the bioactivation of DCE. Furthermore, this bioactivation occurred to a greater extent in lung microsomes from female than from male mice, which suggests that females may be at slightly greater risk for DCE-induced pneumotoxicity.

Antigens identified by monoclonal antibodies in tissue sections of Boophilus microplus

A panel of monoclonal antibodies (mAbs) raised against midgut antigens of Boophilus microplus were used to probe various stages and organs of the tick. One of the monoclonal antibodies in this panel (QU13) has previously been shown to recognize protective antigens. Of the 18 mAbs tested, all except two (QU5 and QU12) reacted with sections of adult midgut and Malpighian tubules using an avidin-biotin alkaline phosphatase method for immunostaining. MAbs QU1, QU2, QU3, QU4, QU12, QU13, and QU18 reacted specifically with the lumenal surfaces of type III acini of the salivary gland. These seven mAbs also stained the midgut in larval sections indicating that the antigens recognized were not stage specific. However, none of the seven mAbs tested recognised antigens in either the adult ovary or the developing egg. Antigens which were immunogold labelled by mAbs QU1, QU4, QU11, QU13, and QU15 in electron microscopy were located either on or near the surface of the microvilli of digestive cells from the midgut of the adult tick. We conclude that common antigens are present on the lumenal surfaces of the adult midgut, type III acini of the salivary gland, and the Malpighian tubules and that these antigens are also located in the larval gut.

Anti-idiotypic antibodies as surrogate antigens for vaccinating against the cattle tick, Boophilus microplus

QU13, a monoclonal antibody (mAb) raised against midgut (GM) antigens from Boophilus microplus and shown to recognise antigens which protect cattle from tick challenge was used to immunise cattle and rabbits to produce anti-idiotypic antibodies (AIA). Polyclonal antisera against mAb QU13 were produced in rabbits and cattle. AIA were purified from these antisera by affinity chromatography procedures. These purified AIA were found to block mAb QU13 binding to GM in enzyme-linked immunosorbent assay (ELISA). AIA purified from bovine antiserum elicited an immune response in cattle to antigens extracted by detergent from the midgut of B. microplus (TXGM) after the fourth vaccination (P = 0.06) compared with the bovine immunoglobulin (Ig) control. The mean antibody level in the group of experimental cattle vaccinated with AIA purified from rabbit antisera was significantly higher (P < 0.03) than that of bovine Ig control cattle after the fourth vaccination and an anamnestic response (P < 0.11) occurred in the rabbit AIA vaccinated group of cattle when a single booster dose of 300 micrograms of TXGM was given after the first tick challenge. The positive control group of cattle vaccinated with TXGM were significantly protected (P < 0.05) against tick infestation after the booster dose of 300 micrograms of TXGM. The AIA vaccinated groups of cattle were not protected against challenge with 20,000 larval ticks either before or after the booster injection of 300 micrograms of TXGM.

In vitro biotransformation of 1,1-dichloroethylene by hepatic cytochrome P-450 2E1 in mice

1,1-Dichloroethylene (DCE) is hepatotoxic in mice and its cytotoxic effects are associated with cytochrome P-450 (P450)-dependent formation of metabolite(s) that bind covalently to tissue macromolecules. Our goal was to investigate effects of DCE on P450 in liver microsomes. Specific objectives were to examine 1) inactivation of P450 by DCE and to determine if during this inactivation the heme and/or apoprotein moieties are destroyed and 2) isozyme-selective biotransformation of DCE by P450. Our results showed significant reduction of P450 content in reactions containing DCE and microsomes from untreated (30%) or phenobarbital-treated (20%) mice. Maximal reduction (50%) of P450 was evoked by DCE in reactions catalyzed by microsomes from acetone-treated mice. Alterations in heme levels were not detected in any microsomal preparation incubated in the presence of DCE. Significant inhibition of p-nitro-phenol hydroxylation was found in microsomes incubated previously with DCE and was most pronounced in acetone-treated mice, as compared to control and phenobarbital-treated mice. DCE did not cause inhibition of 7-pentoxyresorufin-O-dealkylation in any microsomal preparation. Immunoinhibition with an anti-2E1 antibody abolished the observed inhibition of p-nitrophenol hydroxylation. Densitometric scanning of protein immunoblots using an anti-2E1 antibody revealed a 40% decrease in microsomes reacted with DCE, whereas no change was observed in immunoblots prepared with an anti-2B antibody. These results showed that 1) biotransformation of DCE is catalyzed by the 2E1 and not by the 2B enzyme and 2) DCE inactivates P450 by destruction of the apoprotein rather than the heme moieties.

Mesenteric panniculitis presenting as a multilocular cystic mesenteric mass: CT and MR evaluation

Mesenteric panniculitis is a non-neoplastic, inflammatory process affecting the adipose tissue of the mesentery in adults with slight male predilection. Typical computed tomography (CT) or magnetic resonance imaging (MRI) findings are of either diffuse mesenteric infiltration or nodular mesenteric masses. We encountered a case of mesenteric panniculitis in a 26-year-old woman with the left upper quadrant pain and fullness, in which CT and MRI disclosed a large, ill-defined, multilocular cystic mesenteric mass. After surgery, the diagnosis of mesenteric panniculitis was made. The cystic components were dilated lymphatics due to lymphatic and venous obstruction by the mesenteric panniculitis.

Immune responses of cattle to biochemically modified antigens from the midgut of the cattle tick, Boophilus microplus

Treatment of membrane antigens of the midgut (GM) of the cattle tick, Boophilus microplus with sodium metaperiodate (periodate), pronase and lipase significantly inhibited the reactivity of the GM with antibodies in the sera of 57 cattle vaccinated with GM. Treatment of GM with periodate only removed the correlation between antibody reactivity of sera and protection against infestation with ticks. A monoclonal antibody (MoAb QU13), which recognises protective antigens solubilized from GM (Lee + Opdebeeck 1991), did not react with GM treated with periodate. Cattle vaccinated with GM extracts were significantly protected against infestation with cattle ticks (P less than 0.05), whereas cattle vaccinated with either GM extracts treated with periodate or with antigens precipitated from GM extracts with MoAb QU13 and also treated with periodate, were not protected against infestation. These studies provide preliminary evidence that protective antigens in the tick midgut membrane either are carbohydrate or are dependent on carbohydrate for their specificity.

CPAP, effective respiratory support in patients with AIDS-related Pneumocystis carinii pneumonia

Human Immunodeficiency Virus (HIV) related Pneumocystis carinii pneumonia (PCP) associated with severe respiratory failure is an increasingly common problem in major centres and is associated with a high mortality in previous and recent studies. Early in the epidemic, alternatives to invasive intensive care treatment were utilized in our institution and found to be successful. When respiratory failure developed, mask CPAP was used instead of intubation and ventilation. A retrospective review of 175 cases of HIV infected patients with confirmed first presentation PCP was undertaken. Treatment with our protocol resulted in an overall hospital mortality of 9%. Those patients who did not require supplemental oxygen or respiratory support had no in-hospital mortality. The group who required supplemental oxygen had a mortality of 10%. If respiratory failure supervened (severe respiratory distress, PaO2 less than 50 mmHg, SaO2 less than 90% on mask oxygen), CPAP was introduced. The mortality in this group was 22%. Only two patients were admitted to the intensive care unit for respiratory support after failure of CPAP. Both patients were intubated and received intermittent positive pressure ventilation (IPPV). Both patients died.

Isolation of protective antigens from the gut of Boophilus microplus using monoclonal antibodies

Monoclonal antibodies (mAb) were produced against midgut membrane (GM) antigens of Boophilus microplus. The isotypes of these mAb were established and their specificity characterized using double diffusion and Western blotting. GM antigens solubilized by Triton X-100 were precipitated by mAb QU13, and the precipitate was then injected into cattle to test for the presence of protective antigens. Vaccinated cattle challenged with 10-day-old larval ticks showed evidence of protection with a 62% reduction in eggs produced by ticks from vaccinated cattle compared to tick eggs from control cattle. In a second vaccine-challenge experiment, the dose of precipitate was increased and greater than 99% protection was provided to these vaccinated cattle following challenge (calculated from tick egg weights compared to the control group). The solubilized antigen(s) precipitated by QU13 were subjected to SDS-PAGE separation and the calculated sizes of these molecules were greater than 200,000, 80,000, 74,000, 62,000 57,000 and less than 30,000 MW.

Severe heat stroke in an experienced athlete

A 28-year-old experienced athlete suffered severe heat stroke after running competitively in hot, humid conditions. He developed disseminated rhabdomyolysis and acute renal failure. His course was complicated by multiple system organ failure and bismuth iodide (BIPP) toxicity. After almost five months in intensive care he recovered sufficiently to be transferred to the ward and subsequently to a rehabilitation hospital and was eventually able to return to work. Heat stroke can be prevented and this case provides several lessons for the running fraternity and the medical profession.

Right ventricular assist and prostacyclin infusion for allograft failure in the presence of high pulmonary vascular resistance

The presence of high pulmonary vascular resistance (PVR) greater than 4 Wood units contributes to significant early posttransplant mortality, and remains a negative predictor of long-term survival. Current trends have been toward exclusion of the recipient with high PVR from the orthotopic procedure; elective heterotopic allograft placement is increasingly advocated. A patient with a PVR of 6 Wood units underwent orthotopic transplantation; the cardiac allograft from a 12 kg heavier donor was implanted after an ischemic time of 115 minutes. Early graft failure at 4 hours and subsequent cardiac arrest were followed by reinstitution of cardiopulmonary bypass, during which time optimal pharmacologic manipulation of the pulmonary vasculature was undertaken, including the use of high-dose prostacyclin. Refractory right heart failure indicated the requirement for right ventricular assistance (RVA) for patient survival. RVA with a Bio-Medicus pump was instituted in association with high-dose prostacyclin; an intraaortic balloon pump was inserted 12 hours later. Maintenance immunosuppression consisted of cyclosporine and azathioprine alone. RVA was maintained for 3 days; during this time the patient was totally pump dependent. Over an 18-hour period the patient was weaned and successfully withdrawn from RVA. Intraaortic balloon pump counterpulsation and the prostacyclin infusion were continued for 6 and 10 days, respectively. The clinical implications of the various interventions that resulted in the patient's survival are discussed.

Spontaneous activity of primary afferent neurons in diabetic BB/Wistar rats. A possible mechanism of chronic diabetic neuropathic pain

The mechanism of painful diabetic neuropathy remains unknown. Spontaneous activity in nociceptive primary afferents has been implicated in the genesis of chronic pain due to peripheral nerve injury, and diabetic axonopathy shares some histologic features with traumatic neuropathy. We hypothesized that spontaneous hyperactivity of nociceptive neurons might represent the neurophysiologic mechanism of diabetic neuropathic pain. To test this, we examined the spontaneous activity of primary afferent axons from diabetic BB/Wistar and normal Wistar rat saphenous nerves isolated from central and peripheral connections. Microfilament recordings from diabetic nerves showed a significantly higher incidence of spontaneous discharges in comparison to normal nerves. Furthermore, this spontaneous hyperactivity occurred almost exclusively in potentially nociceptive C-fibers. We conclude that in the diabetic BB/Wistar rat, spontaneous impulses are generated in potential nociceptive primary afferent neurons, and that this may represent the mechanism of chronic diabetic neuropathic pain.

Ibuprofen: a severe systemic reaction

Although minor and unpleasant side effects have been reported in patients taking ibuprofen, the drug is generally regarded as a safe nonsteroidal anti-inflammatory agent. A case is reported of a previously healthy woman who experienced a severe reaction to the drug on two separate occasions.

A Comparison of the Surface Polysaccharides from Rhizobium leguminosarum 128C53 smrif with the Surface Polysaccharides from Its Exo Mutant

The surface polysaccharides of Rhizobium leguminosarum 128C53 sm(r)rif(r) (parent) and its exo(-1) mutant were isolated and characterized. The parent carries out normal symbiosis with its host, pea, while the exo(-1) mutant does not nodulate the pea. The following observations were made. (a) The parent produces lipopolysaccharide (LPS), typical acidic extracellular polysaccharide (EPS), and three additional polysaccharides, PS1, PS2, and PS3. The PS1 and PS2 fractions are likely to be the capsular polysaccharide (CPS) and are identical in composition to the EPS. The PS3 fraction is a small-molecular-weight glucan. (b) The exo(-1) mutant produces LPS, EPS, and a PS3 fraction, but does not produce significant amounts of either PS1 or PS2. The LPS from the exo(-1) mutant appears to be identical to the parental LPS. Analysis of the EPS from exo(-1) shows that it consists of two polysaccharides. One polysaccharide is identical to the LPS and comprises 70% of the exo(-1) EPS. The second polysaccharide is identical to the exo(-1) PS3 and comprises 30% of the exo(-1) EPS. This result shows that the exo(-1) mutant does not produce any of the typical acidic parental EPS and that the major polysaccharide released into the media by the exo(-1) mutant is intact LPS. The exo(-1) mutant PS3 fraction was found to contain two polysaccharides, PS3-1 and PS3-2. The PS3-2 polysaccharide is identical to the parental PS3 described above. The PS3-1 polysaccharide has a composition similar to the polysaccharide portion of the LPS. This result suggests that the exo(-1) mutant produces LPS polysaccharide fragments. These LPS polysaccharide fragments are not produced by the parent strain.

Problems of primary health care in a newly developed society: reflections on the Hong Kong experience

Hong Kong has emerged as a newly developed society in Asia and its modern scientific health care system has had a substantial expansion. Recently, the rise of medical costs has made the health authority come to stress the development of PHC. This paper focuses on three major aspects of the PHC development in Hong Kong: (1) public health and preventive care; (2) food supply and nutrition; and (3) first-contact medical care and referral network. It is argued that in a newly developed society, the emphasis on developing both the quality and the quantity of PHC in the scientific biomedical stream is justifiable. However, at least two kinds of problems need to be taken into consideration, i.e. the prevalence of traditional beliefs and practices and the ever-rising demands of the public for health services.

Comparative studies of health care systems

This paper reveals the dynamics of hierarchical medical pluralism through a comparative analysis of the health care systems in three Chinese societies (the China mainland, Taiwan and Hong Kong). It is argued that the hierarchical relationships among medical traditions within a national society should be studied in terms of structural superiority (power, prestige and wealth) and functional strength (distribution and utilization) and should be understood in the context of modernization. The world-wide movement of modernization through science has made scientific biomedicine become structurally superior to other medical traditions in virtually every contemporary society but its functional strength varies with the society's political-organizational and economic development. The national will to modernize through science has also resulted in many alternative traditions being increasingly absorbed into the scientific biomedical sector. The various efforts to revive alternative remedies may turn out to facilitate the process of both technical and organizational absorption by scientific biomedicine.