Pharmacological profile of ZD1611, a novel, orally active endothelin ETA receptor antagonist

The endothelins (ETs), potent vasoconstrictor peptides, have been implicated in the pathogenesis of various cardiovascular disorders. In the present study, we describe the novel, potent, orally active, selective ET(A) receptor antagonist ZD1611 [3-(4-[3-(3-methoxy-5-methylpyrazin-2-ylsulfamoyl)-2-pyridyl ]phenyl)- 2,2-dimethylpropanoic acid]. ZD1611 competitively inhibited (125)I-labeled ET-1 binding at human cloned ET(A) and ET(B) receptors with pIC(50) values of 8.6 +/- 0.1 and 5.6 +/- 0.1, respectively, showing 1000-fold selectivity for the ET(A) receptor. ZD1611 caused a parallel rightward shift of the concentration response curve to ET-1 in the rat isolated aorta yielding a concentration of antagonist that caused a 2-fold rightward shift in the ET-1-response curve (pA(2)) of 7.5 +/- 0.3. When administered i. v. to anesthetized rats and dogs, ZD1611 caused dose-related rightward shifts of partial dose-response curves to the precursor of ET-1, big ET-1. Threshold doses for significant antagonist activity were determined as 0.1 mg/kg and 0.3 mg/kg in the rat and dog, respectively. Importantly, ZD1611 was able to reverse an established big ET-1-induced pressor response in pithed rats in the presence of continuous big ET-1 infusion. Failure of ZD1611 to inhibit the BQ3020 (ET(B)-selective)-induced depressor response in pithed rats indicated a lack of activity at the endothelial ET(B) receptor. ZD1611 was orally active in the rat at 0.3 mg/kg and had a duration of action of more than 7 h, and, in the dog, a dose of 0.6 mg/kg p.o. was active for at least 6 h. In conclusion, these data demonstrate that ZD1611 is a potent and orally active, selective ET(A) receptor antagonist with a long duration of action which may be of therapeutic use.

Functional and phenotypic analysis of thymic B cells: role in the induction of T cell negative selection

The phenotype of mouse thymic B cells and their capacity to induce T cell negative selection in vitro were analyzed. Thymic B cells expressed B cell markers such as IgM, Fc gamma receptor, CD44, heat-stable antigen, LFA-1 and CD40. In addition, they were positive for the activation molecule CD69 and displayed high levels of B7-2. Although thymic B cells expressed CD5 on their surface, no CD5-specific mRNA was detected. Moreover, thymic B cells induced a stronger deletion of TCR-transgenic (TG) thymocytes than splenic B cells, which had low CD69 and B7-2 levels. Interestingly, CD40-activated splenic B cells up-regulated CD69 and B7-2 and acquired a capacity to induce T cell deletion comparable to that of thymic B cells. Moreover, thymic B cells from CD40-deficient mice displayed lower CD69 and B7-2 levels than control thymic B cells, and lower capacity to induce the deletion of TCR TG thymocytes. These results support the hypothesis that CD40-mediated activation of thymic B cells determines a high efficiency of antigen presentation, suggesting that within the thymus B cells may play an important role in the elimination of autoreactive thymocytes.

A bronchogenic cyst in an infant causing tracheal occlusion and cardiac arrest

A 3-month-old infant treated for 3 weeks for suspected bronchiolitis, developed episodes of profound desaturation. A lateral X-ray showed displacement and compression of the trachea. Respiratory arrest, from which she was successfully resuscitated, occurred just before MRI scan. The mass was removed at thoracotomy and a histological diagnosis of a bronchogenic cyst was made. Mediastinal masses in babies are relatively rare, and the situation in which they present with acute respiratory distress may prove extremely challenging to the anaesthetist. Bronchogenic cysts are difficult to diagnose pre-operatively and awareness may assist in the peri-operative management of these infants.

Definition of dendritic cell subpopulations present in the spleen, Peyer's patches, lymph nodes, and skin of the mouse

Dendritic cells (DC) are highly efficient antigen-presenting cells (APC) that have an essential function in the development of immune responses against microbial pathogens and tumors. Although during the past few years our understanding of DC biology has remarkably increased, a precise characterization of the different DC subpopulations remains to be achieved with regard to their phenotype and lineage relationships. In this report, we have extensively studied the DC subpopulations present in the thymus, spleen, Peyer's patches, lymph nodes (LN) and skin of the mouse. Thymus DC and 60% spleen DC have a lymphoid DC phenotype, ie, CD8(+) DEC-205(high) Mac-1(low), whereas 40% spleen DC have a myeloid DC phenotype, ie, CD8(-) DEC-205(low) Mac-1(high). Both CD8(+) and CD8(-) DC are leukocyte function-associated antigen-1 (LFA-1)high and highly adherent. Within Peyer's patches the majority of DC correspond to the CD8(+) DEC-205(high) Mac-1(low) lymphoid category. In the LN, together with CD8(+) and CD8(-) DC, an additional nonadherent CD8(int) LFA-1(int) subpopulation with lymphoid DC characteristics is described. Finally, in the skin both epidermal Langerhans cells (LC) and dermal DC are CD8(-)DEC-205(high) Mac-1 (high), and do not express LFA-1. Interestingly, LC migration experiments indicate that LC underwent the upregulation of CD8 and LFA-1 upon migration to the LN, supporting the hypothesis that LC belong to the CD8(+) lymphoid lineage.

Assessment of patients with memory problems using a nurse-administered instrument to detect early dementia and dementia subtypes

BACKGROUND

With the development of pharmacological treatments for Alzheimer's disease there will be an increase in the numbers of patients requiring assessment from specialist services. Could the role of the specialist clinician be supported by other health professionals screening those who might benefit from treatment?

METHOD

Sixty-four consecutive referrals to the Leicester University Memory Clinic were assessed at home by a community psychiatric nurse using a semi-structured interview. The nurse then reported her findings to a psychiatrist and a diagnosis was agreed. This diagnosis was then compared to the Memory Clinic diagnosis and a standardized (ICD-10) diagnosis recorded by another psychiatrist examining the clinic records.

RESULTS

The nurse assessment procedure performed well in detecting dementia, with a kappa statistic (k) of 0.75 when compared to the standardized and Memory Clinic diagnoses. There was, however, only moderate concordance between the ICD-10 diagnosis and nurse (k = 0.46) and the Memory Clinic and nurse (k = 0.60) for Alzheimer's disease. The relatively low k value for Alzheimer's disease was principally a result of difficult in differentiating vascular dementia.

CONCLUSIONS

A single supervised community psychiatric nurse, using a structured assessment instrument, can adequately detect early dementia in a sample of patients referred with memory problems. Subtypes of dementia are not, however, accurately differentiated.

Evaluation of a quantitative competitive PCR assay for measuring herpes simplex virus DNA content in genital tract secretions

Previous studies have shown an association between the approximate titer of herpes simplex virus (HSV) DNA in clinical specimens and the ability to isolate HSV from genital secretions. To control for variance in amplification conditions, we developed a competitive quantitative PCR (QC PCR) for the detection of HSV DNA. The assay accurately measured from 10 to 10(6) copies of HSV DNA. We compared the QC PCR with our previous semiquantitative detection method and found concordance for 61 of 63 positive specimens. We also evaluated the HSV DNA content from individual swabs of genital secretions obtained from individual sites of the genital tract (cervix, vulva, and rectum) with that from one swab with secretions from all three sites. The concordance for detecting HSV DNA was 91%; for only 4 of 143 collection days was there a > 1 log difference between the two collection methods. A single swab with secretions from all three genital sites and evaluated in a QC PCR format can accurately measure the frequency of subclinical and clinical shedding of HSV and the titer of HSV shed from the genital region. Such an approach should be very useful in the evaluation of antiviral chemotherapy for HSV.

Role of spasmolytic polypeptide in healing of stress-induced gastric lesions in rats

Stress is known to induce gastric ulcerations but the mechanism of their healing has been little studied. This paper describes the studies on mucosal expression and the effect on ulcer healing of spasmolytic peptide (SP), one of the members of the trefoil peptide family. Gastric ulcerations were induced in rats by the exposition to 3.5 h of water immersion and restraint stress. It was found that the number of these lesions gradually declined at 4, 8 and 12 h after stress and this spontaneous healing was significantly accelerated by s.c. infusion of human recombinant SP in a constant dose of 50 micrograms kg-1 h-1. The healing of the stress-induced ulcerations was accompanied by a gradual restoration of gastric mucosal blood flow and the decrease in gastric acid and pepsin secretion towards the normal values. The expression of SP in rats (rSP) was detected by RT-PCR in the intact mucosa and during all tested time periods reaching a peak at 4 h after the stress. Immunostaining for rSP in the intact mucosa was confined to the mucous neck cells, but following the exposure to stress it was significantly enhanced and occurred also in the cells of the basal region of gastric glands, reaching a peak at 4 h after the stress. We conclude that SP plays an important role in healing of stress-induced gastric lesions possibly by the acceleration of the mucosal repair, the enhancement of mucosal blood flow and the inhibition of gastric secretion.

Downgaze paresis following severe head trauma in a child

A 4 1/2-year-old girl developed a downgaze paresis following severe head trauma. Magnetic resonance imaging showed evidence of peri-aqueductal lesions in the rostral midbrain in the region of the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF). Twenty five weeks following the injury, the downgaze paresis remained unchanged but she developed convergence retraction nystagmus on attempted upgaze. Repeat imaging did not show any change in the lesions in the rostral midbrain. This report provides further evidence for the riMLF in the control of downgaze, and a synkinesis is postulated for the development of the convergence retraction nystagmus.

Expression of trefoil peptides in the gastric mucosa of transgenic mice overexpressing transforming growth factor-alpha

Overexpression of transforming growth factor-alpha (TGF-alpha) in the gastric mucosa of metallothionein-TGF alpha (MT-TGF alpha) transgenic mice leads to a marked alteration in the ontogeny of the fundic cellular lineages. Induction of the transgene leads to the over-production of mucous cells with a concomitant diminution in the development of parietal cell and chief cell lineages. We have sought to define more precisely the mucous cell lineages involved in the mucous cell hyperplasia in MT-TGF alpha mice by investigating the expression of trefoil peptides in MT-TGF alpha mice. MT-TGF alpha mice and their non-transgenic littermates were treated with cadmium sulfate beginning at 13 days of age. Animals were then sacrificed at intervals over the following 2 weeks and gastric mucosa was examined for expression of trefoil peptides and TGF alpha by immunohistochemistry and in situ hybridization. No TGF alpha mRNA expression could be demonstrated by in situ hybridization in non-transgenic mice. In MT-TGF alpha mice, in situ grains for TGF alpha mRNA were detected at the base of fundic glands in 13 day old animals, whereas the expression was observed more widely in the mucosa of older animals (28 days). TGF alpha immunoreactivity was observed in foveolar mucous cells and residual parietal cells in MT-TGF alpha mice at all ages. By in situ hybridization, pS2 mRNA was detected in the surface mucous cells in normal gastric mucosa. In MT-TGF alpha mice, pS2 mRNA was found throughout the expanded foveolar region. By in situ hybridization, spasmolytic peptide (SP) expression was observed in the region of the progenitor zone in both groups of mice. By immunohistochemistry, SP expression was noted in a broad band of mucous neck cells deep to the progenitor zone. No gastric expression of intestinal trefoil factor (ITF) was noted in either group of mice. The results demonstrate that the expansion of the foveolar mucous cell compartment in MT-TGF alpha mice is due to the hyperplasia of normal surface cells expressing their particular mucin-associated trefoil peptide, pS2.

Dynamics of risk behavior for HIV infection among young Thai men

The objective of this investigation was to analyze the dynamics of risk for HIV-1 infection among young men in Thailand. We conducted a prospective study in a cohort (n = 1,236) of young men, aged 19-23 years at conscription into the Royal Thai Army and Air Force from six provinces in northern Thailand in May 1991 who were followed until their discharge in April 1993. The outcome measure was change since conscription in the frequency of self-reported sex with female commercial sex workers (CSW) during military service. Although 42% of conscripts reported no visit to a female CSW in the year prior to conscription, most had a visit during military service. Men who visited female CSWs infrequently at baseline increased their visits somewhat over time, whereas those with high initial rates of CSW visits decreased. Based on an assumed stable distribution over time, change from baseline was not statistically significant. Only marital status and high baseline CSW visit rates were associated with diminished visit frequency in multivariate analysis. No differences were seen in patterns of change in CSW visits by HIV-1 serostatus. More aggressive preventive interventions are needed to reduce the frequency of CSW visits in northern Thailand, a setting where 40-80% of all female CSWs working in brothels are now HIV seropositive.

Automatism re-visited: post-traumatic automatism as a defence to a serious criminal charge

A case is described of a policeman who assaulted the man he was arresting after receiving a concussive blow to the head. The defence argued he was suffering from post-traumatic automatism and after juries were unable to agree a verdict in two trials he was acquitted. Aspects of post-traumatic automatism in English law are described and theories of the neurology of concussion and aggressive behaviour are discussed. Guidelines are proposed for the evaluation of cases of post-traumatic automatism.

Trefoil peptides. Coming up clover

Now that information on trefoil domain structure is available from X-ray crystallographic and nuclear magnetic resonance spectroscopy studies, we can begin to understand the functions of these unusual protein motifs.

Seroprevalence of HIV antibodies and risk factors in healthy young males from upper north Thailand

In the Spring of 1991 a random sample of young men from Upper Northern Thailand (mean age = 21 years) was interviewed by trained medical students from Chiang Mai University, serum samples were obtained and analyzed for prevalence of HIV-1 antibodies and for syphilis, and risk factors for HIV infection were assessed. It was found that Commercial Sex Workers (CSW) were the principal risk factor, that consistent condom use is rare, and the rates of HIV infection are rising rapidly. Sociodemographic background, homosexual behavior, drug use, and history of STD's were found to be not significant risk factors. The conclusions are that the education campaigns should be intensified to reduce the frequency of contact with CSW and to encourage consistent use of condoms.

Behavioral and sociodemographic risks for frequent visits to commercial sex workers among northern Thai men

OBJECTIVE

The transmission of HIV-1 in Thailand has recently been attributed to exposure to infected commercial sex workers (CSW). We sought to identify risk factors for patterns of CSW visits among northern Thai men.

DESIGN

Retrospective recall of lifetime and recent CSW visits and associated risk factors were obtained by interview.

SETTING

Two military bases in northern Thailand.

PARTICIPANTS

We enrolled two cohorts (n = 2417) of young men, aged 19-23 years, who were conscripted into the Royal Thai Army and Air Force from six provinces in northern Thailand in May and November 1991.

MAIN OUTCOME MEASURES

Frequency of self-reported lifetime and recent sex with CSW.

RESULTS

Multivariate results showed that lower socioeconomic status, early first intercourse and substance-use factors (alcohol, marijuana, other drugs, and smoking) associated with lifetime and recent sex with CSW. Sexual intercourse with other female partners, lower price paid at last CSW visit and frequency of condom use with CSW did not differentiate frequent from infrequent CSW visitors.

CONCLUSIONS

Limits in the frequency of sex with CSW, improved condom practices and reduction of drinking prior to CSW visits would all appear to provide substantial protection from exposure to HIV-1 in this setting.

Risk factors for HIV infection among young adult men in northern Thailand

OBJECTIVE

To determine the sociodemographic and behavioral risk factors associated with human immunodeficiency virus (HIV) infection in two cohorts of young men selected for military service in northern Thailand.

DESIGN

Military conscripts were studied cross-sectionally after conscription in May 1991 and November 1991. Risk factors were assessed by interview with trained nonmilitary interviewers.

SETTING

Two military training bases in Chiang Mai, Thailand.

PARTICIPANTS

A total of 2417 young men aged 19 to 23 years (mean age, 21 years) conscripted by lottery into military service in the Royal Thai Army or Royal Thai Air Force from six provinces in northern Thailand.

MAIN OUTCOME MEASURES

Human immunodeficiency virus seroprevalence by enzyme-linked immunosorbent assay confirmed by Western blot and univariate and multivariate analyses of sociodemographic and behavioral risk factors associated with HIV seroprevalence.

RESULTS

Overall, 289 (12.0%) of 2417 men were HIV-seropositive at baseline. The strongest associations with being HIV positive were heterosexual activities. History of sex with a female commercial sex worker (CSW) was frequent (96.5% of men who were HIV-positive and 79.0% of men who were HIV-negative) and strongly associated with HIV infection on univariate and multivariate analyses (adjusted odds ratio, 1.60 to 2.07, depending on the frequency of CSW contact). Also, sexually transmitted diseases were common and associated with HIV infection in both univariate and multivariate analyses (adjusted odds ratio, 3.36). Sex with other males and injection drug use were uncommon and not associated with HIV infection. Condom use was reported in 61.5% of men at last sex with a CSW but was not shown to be protective of prevalent HIV infection.

CONCLUSION

The epidemic of HIV infection has spread widely among young men in northern Thailand, despite reported frequent and recent use of condoms during sex with female CSWs. Control of HIV infection in this population will probably require more regular and effective use of condoms, prevention and treatment of sexually transmitted diseases, and reduction in the frequency of CSW contact.

Report of the Canadian Hypertension Society Consensus Conference: 2. Diagnosis of hypertension in adults

OBJECTIVE

To update recommendations for the diagnosis of mild hypertension in adults and to assess the role of echocardiography, self-measurement of blood pressure and ambulatory blood pressure monitoring.

DATA SOURCES

Literature reviews of previous consensus conferences were updated with searches of MEDLINE for the period Jan. 1, 1988, to Nov. 15, 1991, and supplemented by reference lists and personal files.

STUDY SELECTION

Panel members selected relevant articles and rated them according to methodologic criteria.

DATA EXTRACTION

The data extracted concerned the measurement of blood pressure, the diagnosis of hypertension, the treatment of mild hypertension, and the reliability and validity of echocardiography, self-measurement of blood pressure and ambulatory blood pressure monitoring in the diagnosis of mild hypertension. The recommendations made were graded according to the level of evidence available, circulated to many experts and approved at a consensus conference.

MAIN RESULTS

Previous recommendations for the accurate measurement of blood pressure remain mostly unchanged. Antihypertensive treatment should be prescribed for patients (including the elderly) with an average diastolic blood pressure of at least 100 mm Hg, for those with isolated systolic hypertension (systolic blood pressure of at least 160 mm Hg and diastolic blood pressure of less than 90 mm Hg) and for patients with a diastolic blood pressure of 90 to 99 mm Hg and target-organ damage. Clinical judgement is required in treating patients with a diastolic blood pressure of 90 to 99 mm Hg without target-organ damage, and individual risk for cardiovascular disease must be taken into account. There is insufficient evidence to warrant the routine use of echocardiography, self-measurement of blood pressure or ambulatory blood pressure monitoring in diagnosis.

CONCLUSIONS

Recent high-quality evidence supports several new recommendations for the diagnosis of mild hypertension in adults. Additional research is needed to determine the role of echocardiography, self-measurement of blood pressure and ambulatory blood pressure monitoring.

Treatment of hyperlipidemia in the nephrotic syndrome: the effects of pravastatin therapy

The hyperlipidemia of the nephrotic syndrome is characterized by an elevation of total cholesterol (TC) and low-density lipoprotein cholesterol (LDLC), with a normal or low high-density lipoprotein cholesterol (HDLC), and an increase in triglycerides (TGs) later in the course of the disease. If sustained, this lipid profile probably places these patients at increased risk for cardiovascular disease. Despite extensive trials of diet and drug therapy in patients with primary hyperlipidemias, few such trials exist in patients with the nephrotic syndrome. We conducted a randomized, prospective, double-blind, placebo-controlled trial to investigate the efficacy and safety of pravastatin, the newest cholesterol synthesis inhibitor, in the treatment of the hyperlipidemia of the nephrotic syndrome. After dietary modification was implemented, 13 patients received pravastatin and eight received placebo. All patients were maintained on a low-fat, low-cholesterol diet for the duration of the trial (24 weeks). The dose of pravastatin was increased from the initial 20 mg/d to 40 mg/d at week 10 or 18 if TC remained elevated (> 50th percentile). A bile acid sequestrant was added at week 18 if TC remained elevated and if the patient was already receiving the maximal pravastatin dosage. Dietary modification did not significantly change the lipid profile. Pravastatin (20 mg/d) reduced TC by 22% from a baseline of 301 +/- 28 mg/dL (P < 0.05) and LDLC by 28% from a baseline of 222 +/- 28 mg/dL (P < 0.05). When used at 40 mg/d (in six patients) no further change in the lipid profile was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

An approach to consumer feedback in an out-patient specialty service

Details an approach to consumer feedback in an out-patient specialty service. Outlines the approach to undertaking a consumer survey and how feedback from people using the Genito-Urinary Medicine services can be obtained. The aim of the survey was to assess the level of individual/personal care. Gives the objectives and methodology, main findings and recommendations, together with a cost benefit analysis of the work.

Glycine toxicokinetics: vitreous fluid concentration and visual impairment

We report the results of kinetic experiments in sheep. Following systemic loading with 45 g glycine, plasma, cerebral spinal fluid (CSF), and vitreous fluid from the vitreous body of the eye were assayed for glycine concentrations. Mean baseline plasma, CSF, and vitreous glycine concentrations were 730, 46, and 191 mumol/L respectively. One hour after loading, values were 21292, 1103, and 1150 mumol/L respectively. During the succeeding 7 h plasma and CSF concentrations fell in parallel but remained above normal. In contrast the vitreous concentrations remained high and did not change significantly during the 7 h post-infusion period. Retinal glycine receptors may be particularly vulnerable to neurotoxic effects of glycine because of these pharmacokinetic properties.