Cardiac and vascular responses after monocrotaline-induced hypertrophy in rats

In rats, monocrotaline causes pulmonary vascular damage leading to pulmonary hypertension, right ventricular hypertrophy, and eventually heart failure. This study determined the inotropic and chronotropic responses in isolated cardiac tissues from pulmonary hypertensive rats (single treatment with monocrotaline, 105 mg/kg) to noradrenaline, forskolin, EMD 57033 (calcium sensitizer), and calcium chloride. Further, vasoconstrictor responses to noradrenaline, 5-hydroxytryptamine (5-HT), and KCl were measured in isolated pulmonary artery and thoracic aortic rings. Marked right ventricular hypertrophy was evident 4 weeks after treatment; at 6 weeks, treated rats additionally showed symptoms of severe heart failure. Pulmonary hypertension led to marked increases in pulmonary artery responses to 5-HT and to decreases in positive inotropic responses in right ventricular papillary muscles to all compounds except calcium chloride. The development of heart failure maintained or increased these changes. Positive chronotropic responses were unchanged. In the right ventricle, beta1-adrenoceptor density decreased only in heart failure; beta2-adrenoceptor density was unchanged. The densities of both beta-adrenoceptor subtypes were decreased in the lungs but increased in the liver of pulmonary hypertensive rats. The functional changes in the failing human heart are similar to those in rats with monocrotaline-induced right ventricular hypertrophy. This may be a useful model to define adequate therapy in human right ventricular failure.

Volunteer stroke scheme revisited

A project with several strands was carried out with a local Volunteer Stroke Scheme (VSS) which evaluated current practice; identified gaps in practice on which a training programme was based: and then evaluated the outcome of this training in subsequent activities.

Angiotensin receptors in cardiac and renal hypertrophy in rats

Angiotensin II mediates its effects through activation of specific angiotensin (AT) receptors which can be regulated during cardiovascular disease. This study has investigated whether an increased cardiac and renal AT receptor density is important in the development of left ventricular and renal hypertrophy in three rat models of hypertension [spontaneous hypertensive (SHR), deoxycorticosterone acetate (DOCA)-salt and 2K1C renal hypertensive rats]. Although all hypertensive rats developed left ventricular and renal hypertrophy, AT receptor density increased only in the left ventricle and kidney of SHR during the development of hypertension. Thus, cardiac and renal hypertrophy per se do not increase AT receptor density. AT receptors were increased in the liver of DOCA-salt rats, 2K1C rats and 52-week-old SHR and in adrenal glands of DOCA-salt rats and SHR. A plausible explanation for tissue-dependent AT receptor regulation involves tissue-selective control of local renin-angiotensin systems independent of circulating hormone levels, combined with disease-induced cell damage.

Isolation and characterization of a novel epithelium-specific transcription factor, ESE-1, a member of the ets family

We report here the isolation of a novel, highly tissue-restricted member of the ets transcription factor/oncogene family, ESE-1 (for epithelium-specific Ets), which has features distinct from those of any other ets-related factor. ESE-1 contains two putative DNA binding domains: an ETS domain, which is unique in that the 5' half shows relatively weak homology to known ets factors, and an A/T hook domain, found in HMG proteins and various other nuclear factors. In contrast to any known ets factors, ESE-1 is expressed exclusively in epithelial cells. ESE-1 expression is induced during terminal differentiation of the epidermis and in a primary human keratinocyte differentiation system. The keratinocyte terminal differentiation marker gene, SPRR2A, is a putative target for ESE-1, since SPRR2A expression during keratinocyte differentiation correlates with induction of ESE-1 expression, and ESE-1 binds with high affinity to and transactivates the ets binding site in the SPRR2A promoter. ESE-1 also binds to and transactivates the enhancer of the Endo A gene, a potential target for ESE-1 in simple epithelia. Due to the important role that other ets factors play in cellular differentiation, ESE-1 is expected to be a critical regulator of epithelial cell differentiation.

Tissue-specific changes in angiotensin II receptors in streptozotocin-diabetic rats

While there have been reports on changes in the renin-angiotensin system and angiotensin II (AT) receptors in diabetes, there is no agreement on the nature of these changes. This study has characterised specific AT receptors in the heart, kidney, liver and adrenal glands of the streptozotocin (STZ)-diabetic rat using radioligand binding studies with the radioligand 125I-[Sar1, Ile8]-angiotensin II. Left ventricular AT receptor density increased by 135% 4 weeks after treatment and by 206% 12 weeks after treatment; in the liver, AT receptor density increased by 476% (4 weeks) and 263% (12 weeks) and in the adrenal gland by 236% (4 weeks) and 109% (12 weeks). In contrast, renal AT receptor density decreased by 49% (4 weeks) and 36% (12 weeks). Competition-displacement assays with losartan, an AT1-selective ligand, showed that the proportion of AT receptor subtypes remained unchanged. STZ treatment decreased plasma angiotensinogen by 72% (4 weeks) and 67% (12 weeks) and increased plasma renin concentration after 12 weeks; plasma renin activity and aldosterone concentrations remained unchanged. Treatment with human insulin (5 U/day) attenuated changes in plasma angiotensinogen and AT receptor density except in the left ventricle. We conclude that there are major changes in AT receptors in the STZ-diabetic rat that are tissue-specific and time-dependent. Plasma angiotensinogen and renin secretion change in directions that result in the maintenance of plasma renin activity and aldosterone concentration.

The effect of age and weight on the response to formalin inactivated, alum-adjuvanted hepatitis A vaccine in healthy adults

Formalin-inactivated, alum-adsorbed, hepatitis A vaccine was evaluated in 100 healthy adults who were stratified at enrollment into two age groups: 18-39 years: n = 50; 40-65 years: n = 50. All individuals received vaccine at 25 U of viral antigen. After stratification, both groups were randomized to receive either vaccination at 0 and 24 weeks or vaccination at 0.2 and 24 weeks. Subjects were bled for serology at 0, 2, 4, 24, 28 weeks and 1 year. The seroconversion rate and geometric mean titer (GMT = mIU ml-1) after one dose of vaccine was lower for older subjects [second week: < 40 years: 15/25 (60%) (GMT: 12.9). > 40 years: 5/22 (23%) (GMT: 6.1): fourth week: < 40 years: 20/22 (91%) (GMT: 29.0), > 40 years: 16/23 (70%) (GMT: 14.3)]. After a second dose at 2 weeks the seroresponse improved so that there were no longer differences between age groups [24 weeks: < 40: 21/22 (95%) (GMT: 123.9), > 40: 22/23 (96%) (GMT: 106.1)]. A third dose at 24 weeks resulted in a 20-40-fold increase in GMT in both age groups. As a separate evaluation height, weight, skin fold thickness, and body mass index (BMI) were assessed by logistic regression for their ability to predict serologic response. Serologic response was significantly associated with lower weight (P = 0.032) and BMI (P = 0.024) but not with height or skin fold thickness. Hepatitis A vaccine was well tolerated, with no serious adverse experiences. Adults older than 40 years appear to respond less well than younger adults to a single dose of 25 U of hepatitis A vaccine but equally well after two doses of vaccine. The slower antibody response to hepatitis A vaccine in overweight individuals was not attributable to skin adipose tissue.

Drug clearance and arterial uptake after local perivascular delivery to the rat carotid artery

OBJECTIVES

We attempted to characterize how drug released into the perivascular space enters the arterial wall and how it is cleared from the local environment.

BACKGROUND

Drug released into the perivascular space can enter the artery either from the adventitial aspect or from the lumen after absorption by the extraarterial capillaries and mixing within the systemic circulation. Some investigators suggest that this latter mechanism dominates, and they question whether local drug release is synonymous with local deposition.

METHODS

We investigated both the pathways by which adventitially released drug is cleared from the perivascular space and those by which drug enters the blood vessel wall. Inulin was used to follow drug release from implanted devices and subsequent entry to the circulation, because of its first-pass urinary excretion. Heparin was used to follow arterial deposition because of its vasoactivity and tissue-binding properties. The different potential pathways of drug entry and egress were systematically removed and the effects on metabolism and deposition determined.

RESULTS

Ligature occlusion of the artery did not decrease inulin excretion or heparin deposition. Extravascular wraps designed to shield the device from extramural capillaries reduced inulin excretion rates 10-fold but did not alter heparin deposition into the vessel wall. The deposition of drug after perivascular delivery was 500 times higher than after intraperitoneal administration.

CONCLUSIONS

Although almost all the drug released into the perivascular space is cleared through the extravascular capillaries, virtually all the deposited drug diffuses directly from the perivascular space, and little arrives from the endovascular aspect. These data support the view that local drug release leads directly to increased local drug concentration.

Experiences of physical and sexual abuse in Australian general practice attenders and an eating disordered population

OBJECTIVE

To determine the reported rates of child physical and sexual abuse experienced by hospitalised eating disordered patients compared to a control group of women attending general practitioners.

METHOD

A retrospective survey using the self-report Finkelhor Sexual Life Events Inventory and clinical reports.

RESULTS

Nearly one-half of eating disordered patients reported a history of child sexual abuse and one-quarter reported child physical abuse. These rates were significantly higher than those reported by the control group.

CONCLUSIONS

Direct questioning regarding trauma histories is warranted when assessing patients with eating disorders and attention to such issues should be incorporated into the total management plan.

Long-term attendance at a family practice teaching unit. Qualitative study of patients' views

OBJECTIVE

To identify the factors that contribute to patients' long-term attendance at a family practice teaching unit.

DESIGN

Qualitative method of focus groups.

SETTING

A community-based family practice teaching unit in southwestern Ontario.

PARTICIPANTS

Patients who had been coming to St Joseph's Family Medical Centre for more than 15 years were purposefully selected to participate.

METHOD

Five focus groups composed of patients who had been affiliated with one of the three practices at the Centre for more than 15 years explored factors contributing to long-term attendance.

MAIN FINDINGS

Four key themes were identified as the primary factors contributing to long-term attendance: the relationship context, the team concept, professional responsibility and attitudes, and comprehensive and convenient care.

CONCLUSION

The resource-rich era of medical care, during which participants formulated their views and opinions about the factors contributing to their long-term attendance at a family practice teaching unit, has come to a close. The findings of this study provide important information that could help maintain one of the basic tenets of family medicine-continuity of care.

Regulation of heme biosynthesis in Salmonella typhimurium: activity of glutamyl-tRNA reductase (HemA) is greatly elevated during heme limitation by a mechanism which increases abundance of the protein

In Salmonella typhimurium and Escherichia coli, the hemA gene encodes the enzyme glutamyl-tRNA reductase, which catalyzes the first committed step in heme biosynthesis. We report that when heme limitation is imposed on cultures of S. typhimurium, glutamyl-tRNA reductase (HemA) enzyme activity is increased 10- to 25-fold. Heme limitation was achieved by a complete starvation for heme in hemB, hemE, and hemH mutants or during exponential growth of a hemL mutant in the absence of heme supplementation. Equivalent results were obtained by both methods. To determine the basis for this induction, we developed a panel of monoclonal antibodies reactive with HemA, which can detect the small amount of protein present in a wild-type strain. Western blot (immunoblot) analysis with these antibodies reveals that the increase in HemA enzyme activity during heme limitation is mediated by an increase in the abundance of the HemA protein. Increased HemA protein levels were also observed in heme-limited cells of a hemL mutant in two different E. coli backgrounds, suggesting that the observed regulation is conserved between E. coli and S. typhimurium. In S. typhimurium, the increase in HemA enzyme and protein levels was accompanied by a minimal (less than twofold) increase in the expression of hemA-lac operon fusions; thus HemA regulation is mediated either at a posttranscriptional step or through modulation of protein stability.

[Severe methicillin-resistant Staphylococcus aureus infections. Emergence of resistance to fusidic acid or fosfomycin during treatment with continuous infusion of vancomycin]

OBJECTIVES

To evaluate the development of resistance to fosfomycin or fucidic acid in severe infections caused by methicillin-resistant Staphylococcus aureus (MRSA) and to assess the relationship with serum levels of vancomycin

METHODS

A retrospective study was performed in patients hospitalized in our intensive care unit during a 3-year period (1993-1995) who were treated for severe MRSA infection with continuous infusion vacomycin and fosfomycin or fucidic acid. We analyzed the development of resistance and serum levels of vancomycin.

RESULTS

During this period, only 20 patients received continuous infusion vancomycin plus fucidic acid or fosfomycin. MSRA resistant to fucidic or fosfomycin developed in 9. Vancomycin serum levels were significantly lower in patients who developed resistance to focidic acid or fosfomycin, both during the first 5 days of treatment (16.68 +/- 1.07 micrograms/ml vs. 22.64 +/- 1.05 mg/ml, p < 0.01) and throughout treatment duration (17.29 +/- 1.07 micrograms/ml vs. 21.85 +/- 0.78 microgram/ml, p < 0.01).

CONCLUSIONS

Our findings confirm that in spite of continuous vancomycin infusion at an initial rate of 2 g/24 h, Staphylococcus aureus resistance to fosfomycin or fucidic acid an develop during ongoing treatment. Vancomycin levels of at least 20 micrograms/ml should be obtained as rapidly as possible.

Child physical and sexual abuse and eating disorders: a review of the links and personal comments on the treatment process

OBJECTIVE

The aim of the present paper is to review the available literature on abusive experiences and the development of eating disorders, with particular reference to the theoretical basis of the possible links between them.

METHOD

The review covers the literature of both interpersonal violence and eating disorders, with special reference to that linking the two fields. Brief case reports and clinical experience from a specialised eating disorders unit are also described.

RESULTS

Despite much theoretical speculation of a causal relation between abuse and eating dysfunction there is a lack of empirical research to confirm such theories, and a dearth of treatment suggestions to deal with the comorbid problems of the patient with an eating disorder and a history of abuse.

CONCLUSIONS

There is a need for more clinical and experimental focus in this area, particularly in the study of aetiology and the management of dually affected individuals.

Azoospermic men with deletion of the DAZ gene cluster are capable of completing spermatogenesis: fertilization, normal embryonic development and pregnancy occur when retrieved testicular spermatozoa are used for intracytoplasmic sperm injection

Some men with non-obstructive azoospermia harbour fully formed spermatozoa within their testicular tissue that can be used to achieve pregnancy via intracytoplasmic sperm injection (ICSI). Recently, Reijo et al. (1995) provided compelling evidence that the DAZ gene cluster is a strong candidate for one of the elusive azoospermia factors (AZF) located on the long arm of the Y chromosome. The DAZ gene cluster is deleted in 13% of azoospermic men and a small percentage of severely oligozoospermic men. Vertical transmission from father to son of AZF region deletions has also been described. Presumably these fathers were oligozoospermic. This led us to ask whether the azoospermic male with deletions of the AZF/DAZ region can also complete minimal spermatogenesis and whether any spermatozoa found could participate in fertilization, embryo development and pregnancy. Three out of six (50%) of the azoospermic men with AZF/DAZ deletions had spermatozoa identified within their harvested testicular tissue. When these spermatozoa were used for ICSI, fertilization occurred in 36% of injected oocytes. This compared favourably with testicular spermatozoa retrieved from non-obstructive azoospermic men without AZF/DAZ gene deletions. In one case, a twin conception resulted, which represents the first term pregnancy reported using spermatozoa from an AZF/DAZ deleted azoospermic male. Therefore it is necessary to take the possibility of transmission of infertility or sterility to our patients' offspring seriously when utilizing today's reproductive technologies, as spermatogenesis in men with AZF/DAZ deletions is by no means an exceptional occurrence.

Mutations that increase expression of the rpoS gene and decrease its dependence on hfq function in Salmonella typhimurium

The RpoS transcription factor (also called sigmaS or sigma38) is required for the expression of a number of stationary-phase and osmotically inducible genes in enteric bacteria. RpoS is also a virulence factor for several pathogenic species, including Salmonella typhimurium. The activity of RpoS is regulated in response to many different signals, at the levels of both synthesis and proteolysis. Previous work with rpoS-lac protein fusions has suggested that translation of rpoS requires hfq function. The product of the hfq gene, host factor I (HF-I), is a ribosome-associated, site-specific RNA-binding protein originally characterized for its role in replication of the RNA bacteriophage Qbeta of Escherichia coli. In this study, the role of HF-I was explored by isolating suppressor mutations that map to the region directly upstream of rpoS. These mutations increase rpoS-lac expression in the absence of HF-I and also confer substantial independence from HF-I. DNA sequence analysis of the mutants suggests a model in which the RNA secondary structure near the ribosome binding site of the rpoS mRNA plays an important role in limiting expression in the wild type. Genetic tests of the model confirm its predictions, at least in part. It seems likely that the mutations analyzed here activate a suppression pathway that bypasses the normal HF-I-dependent route of rpoS expression; however, it is also possible that some of them identify a sequence element with an inhibitory function that is directly counteracted by HF-I.

Optimisation of a peptide-based indirect ELISA for the detection of antibody in the serum of HIV-1 seropositive patients

A modified peptide-based indirect ELISA technique for the detection of HIV-1 specific antibodies in the sera of HIV-1 seropositive individuals is described. We found that the reduction of non-specific binding of HIV-1 seropositive sera to the ELISA plate was essential for the reliable detection of serum antibodies in the peptide based indirect ELISA. Optimal results were obtained using Immulon microtitre plates, different concentrations of denatured. purified grade of casein in the blocking (1%) and washing (0.25%) solutions and by diluting HIV-1 seropositive sera 1 in 1600. These conditions reduced non-specific binding and improved assay sensitivity. We show that the inclusion of a control peptide is essential to reducing the incidence of false positive and false negative results. Taken together, the modifications described in this report improve reliability of the peptide-based indirect ELISA without compromising its sensitivity and have particular relevance for those wishing to apply the peptide-based indirect ELISA technique to serum samples which exhibit high levels of non-specific binding. To illustrate this, levels of antibody in the sera of HIV-1 seropositive and seronegative donors that are specific for peptides derived from a conserved region of HIV-1 gp120 sharing homology with the FAS apoptosis antigen were analysed using this technique.

Infant feeding practices of low-income African American women in a central city community

It is a well-established fact that nutrition is central to the growth and development of all infants. Yet it has been observed that health care professionals are frequently unfamiliar with the most typical infant feeding practices of the clients within the communities they attempt to serve. This observation was apparent during the development of a program in an inner-city community of Wisconsin to support the feeding practices of low-income African American women with low-birth-weight infants. As a result of initial encounters with prospective clients and health care and social service professionals from the targeted community, it was apparent that professionals and staff involved in this project needed to gain an understanding of common infant feeding practices of low-income African American women; a greater awareness of the values, beliefs, and health care practices of the population; and a greater understanding of the impact of poverty on the families within the targeted community. To assist the staff in gaining a better understanding of the influence of culture and economics on infant feeding practices, a study of the infant feeding practices of a select group of low-income African American women was undertaken. The study aimed to (a) gather information that could be used to describe common infant feeding practices of low-income African American women in an inner-city community of Wisconsin and (b) determine the influence of cultural and economic variables on the decisions made by low-income African American women regarding infant feeding. This article presents an analysis and summary of the data collected during the course of the study.

Quantification of insulin release from implantable polymer-based delivery systems and augmentation of therapeutic effect with simultaneous release of somatostatin

Insulin injections control diabetes mellitus but do not reproduce physiologic regulation. Polymer-based controlled-release technology has enabled us to demonstrate: that the controlled release of insulin from polymer matrices can indeed be used to control diabetes mellitus but does so at the expense of hyperinsulinemia and hypoglycemia; and that somatostatin can be delivered in similar fashion, so as to provide glucose homeostasis in a more physiologic range, at lower insulin levels and at somatostatin doses below those used in intermittent infusion studies; and, that microgram quantities of a drug can be delivered successfully in vivo with intact biological function and in a manner that can be monitored continuously. In the present study the simultaneous polymer-matrix-controlled release of insulin with somatostatin extended glycemic control in diabetic rats. Eleven rats received subcutaneous polymer matrix implants containing insulin alone and 11 rats received implants containing insulin and somatostatin. Plasma and urinary glucose control were improved in both groups. Glucose concentrations in the insulin alone group remained depressed for 5 days until insulin release from the matrices declined below 11.6 units/kg/day. When somatostatin was delivered at 0.75-1.1 micrograms/kg/day together with insulin, plasma glucose control persisted for 12 days until insulin release decreased below 3.6 units/kg/day. It is our hope that further experiments regarding the potential role of both controlled-release devices and somatostatin will be performed to provide continuing therapeutic alternatives to the insulin-dependent diabetic. This is also the first in vivo demonstration of the simultaneous release of two biologically active peptide hormones from polymer matrices. The use of the polymer matrix systems may not only have profound effects on the ambulatory care of diabetes but might also permit the investigation of the synergistic effects of other families of compounds.