Biomedical subjects

B A Evans

Publications and source records attributed to B A Evans.

At least 19 recordsLinked to original sources

PubMed1998

Mapping the gene for sex-linked anemia: an inherited defect of intestinal iron absorption in the mouse.

The sex-linked anemic (sla) mouse carries an anemia that results from an inherited defect of intestinal iron absorption and provides an ideal model with which to investigate this poorly understood yet clinically important process. We have precisely mapped the sla locus within the central region of the X chromosome in relation to a panel of microsatellite markers. Analysis of over 500 progeny from an intraspecific intercross and a smaller intraspecific backcross segregating sla established the following locus order in the sla region: DXMit45-sla- (DXMit16, DXMit96)-DXMit41-DXMit169-DXMit170- DXMit148-(DXMit18, DXMit171)-DXMit84-DXMit64. The two microsatellites DXMit16 and DXMit96 are located 0.60 +/- 0.35cM from sla and form the telomeric limit of the sla region. The mapping of the sla locus is an important first step to identifying the gene itself.

Anemia, Iron-Deficiency↗

PubMed1998

Heterosexual behaviour, risk factors and sexually transmitted infections among self-classified homosexual and bisexual men.

Our study of men presenting at a genitourinary medicine clinic shows that self-classification into homosexual or bisexual does not accurately define behaviour. We found that 8.5% of self-defined homosexual men had had heterosexual intercourse in the past year and that 26% of self-defined bisexual men had not. Overall, 19% of homosexual/bisexual men reported vaginal intercourse in the past year and a further 42% in their lifetime. Compared with heterosexual men attending our clinic, the practising bisexual men were significantly more likely to come from a white ethnic group (P < 0.003) and to use condoms invariably with regular female partners (P = 0.0001). There was no significant difference in consent for HIV testing between homosexual (43%), practising bisexual (49%) and heterosexual (42%) men despite significantly different perceptions of risk. None of the practising bisexual men was seropositive for HIV infection (P = 0.06) or for syphilis (P = 0.02), or had chlamydial infection, which was found infrequently among homosexual men in general (P = 0.00001). HIV infection found in 19.4% of the exclusively homosexual men was associated with more frequent alcohol consumption (P=0.06).

Adult↗

PubMed1997

Central levodopa metabolism in Parkinson's disease after administration of stable isotope-labeled levodopa.

We report the use of a new stable isotope-labeled form of levodopa (LD) to examine in vivo central LD metabolism in Parkinson's disease (PD). Eight patients representing a wide spectrum of disease severity were administered 50 mg of carbidopa orally followed in 1 hour by an intravenous bolus of 150 mg of stable isotope-labeled LD (ring-1',2',3',4',5',6'-(13)C6). Serial blood samples were taken every 30 to 60 minutes and a lumbar puncture was performed 6 hours after the infusion. The average percentage of labeled homovanillic acid (HVA) in lumbar cerebrospinal fluid (CSF) was 54% (SD, 9%; range, 34-67%). The mean CSF labeled HVA concentration was 34.7 ng/ml (SD, 20.2 ng/ml; range, 11.3-67.9 ng/ml). Area under the curve for labeled serum LD closely predicted CSF labeled HVA concentrations (r = 0.747, p = 0.033). Labeled CSF HVA levels did not significantly correlate with either quality or duration of response to the labeled LD dose. In a similar manner, labeled CSF HVA concentrations were not influenced by duration of disease or previous daily LD dosage. These findings support the hypothesis that levodopa-induced benefit in PD is not severely limited by a defect in central levodopa metabolism.

Adult↗

PubMed1997

Functional and molecular evidence for beta 1-, beta 2- and beta 3- adrenoceptors in human colon.

1. Relaxation of carbachol pre-contracted human colonic muscle to (-)-isoprenaline was examined in circular, longitudinal and taenia coli preparations to determine the beta-adrenoceptor subtypes involved. beta 1-, beta 2- and beta 3-Adrenoceptor mRNAs were also measured in colonic muscle and mucosa. 2. (-)-isoprenaline caused relaxation of longitudinal smooth muscle preparations with pEC50-7.39 +/- 0.12, and this response was inhibited by both propranolol (0.1 microM, pKB 8.55 +/- 0.12) and the selective beta 1-antagonist, CGP 20712A (0.1 microM, pKB 8.80 +/- 0.20), while the selective beta 2-antagonist, ICI 118551 (0.1 microM) failed to inhibit isoprenaline relaxation consistently. 3. (-)-Isoprenaline caused relaxation of taenia coli with a pEC50 of 6.70 +/- 0.17. Propranolol (0.1 microM). CGP 20712A (0.1 microM) and ICI 118551 (0.1 microM) inhibited the isoprenaline response with similar low affinities (pKB values 7.93, 7.71 and 7.54, respectively). Carbachol pre-contracted circular smooth muscle preparations failed to relax consistently to isoprenaline and these responses were not characterized. 4. beta 1- and beta 2-Adrenoceptor mRNAs were present in circular longitudinal muscle samples and taenia coli samples, and lower levels were detected in mucosa. beta 3-mRNA was also present in both muscle preparations but was not detected in human colonic mucosa. 5. In summary, beta 1-adrenoceptors are the predominant subtype mediating isoprenaline-induced relaxation of the thin longitudinal smooth muscle of human colon, while beta 1-receptors do not appear to be involved in these responses. However, beta 3-adrenoceptors may play a role in relaxation of the taenia coli as conventional antagonist affinities are low. beta 3-Adrenoceptor mRNA was present in taenia coli and circular/longitudinal smooth muscle but absent from human colonic mucosa.

Adrenergic beta-Agonists↗

PubMed1997

Evaluation of sorivudine (BV-araU) versus acyclovir in the treatment of acute localized herpes zoster in human immunodeficiency virus-infected adults. The Multinational Sorivudine Study Group.

The clinical efficacy and safety of sorivudine as treatment for acute cutaneous zoster in human immunodeficiency virus-infected adults was compared with that of acyclovir in a double-blinded randomized study. A total of 125 patients with laboratory-confirmed zoster rash present for < or =72 h were assigned treatment with either 40 mg of sorivudine once daily or 800 mg of acyclovir five times daily, both taken orally for 7 days. Patients were assessed daily until all lesions crusted and then monthly for 6 months for postherpetic neuralgia (PHN) and for 12 months for recurrent or new episodes of zoster. Sorivudine significantly shortened the median period of new vesicle formation from 3.0 to 4.0 days (log rank P = .0001). Sorivudine was effective regardless of duration of rash before treatment. Zoster recurrences and new episodes were experienced by fewer patients assigned sorivudine (11%) than acyclovir (26%, P = .037). No differences were seen in incidence, severity, or duration of either acute neuritis or PHN. Both treatments were well tolerated.

Acute Disease↗

PubMed1997

Phenotypic diversity in siblings with partial androgen insensitivity syndrome.

The androgen insensitivity syndrome is a heterogeneous disorder with a wide spectrum of phenotypic abnormalities, ranging from complete female to ambiguous forms that more closely resemble males. The primary abnormality is a defective androgen receptor protein due to a mutation of the androgen receptor gene. This prevents normal androgen action and thus leads to impaired virilisation. A point mutation of the androgen receptor gene affecting two siblings with partial androgen insensitivity syndrome is described. One had cliteromegaly and labial fusion and was raised as a girl, whereas the other sibling had micropenis and penoscrotal hypospadias and was raised as a boy. Both were shown to have the arginine 840 to cysteine mutation. The phenotypic variation in this family is thus dependent on factors other than abnormalities of the androgen receptor gene alone.

Female↗

PubMed1997

Sexual relationships, risk behaviour, and condom use in the spread of sexually transmitted infections to heterosexual men.

OBJECTIVE: To examine the effect of patient defined non-regular sexual relationships and other risk behaviours on the incidence of sexually transmitted infections in heterosexual men and the role of condom use in the prevention of their spread. DESIGN: A prospective cross sectional study of sexual behaviour reported by a standardised self administered questionnaire in new patients who presented for screening and diagnosis. SETTING: A genitourinary medicine clinic in west London. SUBJECTS: 957 consecutive newly attending heterosexual men who completed a sexual behaviour questionnaire in 1993/94. MAIN OUTCOME MEASURES: Variables relating to sociodemographic status, sexual behaviour, condom use, sexually transmitted infections and testing for HIV infection, stratified by the reporting of non-regular partners. RESULTS: We found that the 65% of men who reported non-regular sexual partners were more likely to be white collar class (d = 7.5%, 95% CI = 1.3, 13.7) and to have had sexual intercourse with non-United Kingdom born women (d = 7.8%, 95% CI = 3.5, 12.2). They also reported coitarche before 16 years of age (d = 13.4%, 95% CI = 8.0, 18.8) and many more sexual partners both in the last year (d = 13.1%, 95% CI = 10.2, 16.0) and in their lifetime (d = 27.9%, 95% CI = 21.6, 34.2). They were significantly more likely to practise anal intercourse (d = 8.7%, 95% CI = 3.3, 14.1), to smoke (d = 16.3%, 95% CI = 9.8, 22.6), to drink alcohol (d = 4.9%, 95% CI = 1.2, 8.6), and to have chlamydial infection (d = 5.7%, 95% CI = 2.2, 9.2), of which 30% was subclinical. Increasing condom use with regular partners correlated with decreasing incidence of urethral infection (gonorrhoeal and/or chlamydial infection) (p < 0.03) and candidal balanitis (p < 0.03) and a greater likelihood of no infection being detected (p = 0.0002). Use of condoms with non-regular partners was much more frequent than with regular partners (d = 21.4%, 95% CI = 16.7, 26.1). However, we found evidence of oral transmission of urethral gonorrhoea and chlamydial infection among men who reported always using condoms. HIV infection was found in only two men (0.2%), both of whom reported intercourse with non-United Kingdom born women. CONCLUSIONS: Heterosexual men who reported non-regular sexual relationships compensated for their increased risk lifestyle by using condoms more frequently and showed only an increased incidence of chlamydial infection. More consistent condom use with regular partners was significantly associated with the absence of sexually transmitted infection. These findings suggest that transmission between regular partners has been underestimated.

Adolescent↗

PubMed1996

Low incidence of androgen receptor gene mutations in human prostatic tumors using single strand conformation polymorphism analysis.

It is possible that structural changes of the androgen receptor (AR) contribute to the insensitivity of prostatic carcinomas to endocrine therapy. We have isolated DNA from 58 human prostate tumor specimens (31 carcinomas pretreatment, 13 carcinomas after relapse to hormonal therapy, and 14 benign prostatic hyperplasia), three established human prostate carcinoma cell lines and two transplantable human prostatic carcinoma xenografts. Twelve pairs of oligonucleotide primers were used to amplify the majority of the coding region of the AR gene and the products screened for mutations using single-strand conformation polymorphism (SSCP) techniques. In one tumor sample a cytosine to guanine transition in exon F which leads to substitution of glutamic acid for the wild type glutamine at position 798 of the ligand binding domain was detected. The same mutation was also found in the patient's genomic DNA and as been described in a patient with partial androgen insensitivity syndrome. Intronic mutations were detected in two of the benign prostatic hyperplasia samples, and a silent mutation at nucleotide 995 was found to be present in eight poorly differentiated carcinomas, one BPH specimen, as well as in the cell line DU145 (18% of the samples studied). In agreement with most of the literature, these studies indicate that AR mutations are rare both prior to therapy and even in androgen relapsed tumors.

Humans↗

PubMed1996

Functional analysis of six androgen receptor mutations identified in patients with partial androgen insensitivity syndrome.

Partial androgen insensitivity syndrome (PAIS) is caused by defects in the androgen receptor gene and presents with a wide range of undervirilization phenotypes. We studied the consequences of six androgen receptor ligand-binding domain mutations on receptor function in transfected cells. The mutations, Met742Ile, Met780Ile, Gln798Glu, Arg840Cys, Arg855His and Ile869Met, were identified in PAIS patients with phenotypes representing the full spectrum seen in this condition. In all cases the androgen receptor was found to be defective, suggesting that the mutation is the cause of the clinical phenotype. The Gln798Glu mutation is exceptional in that it did not cause an androgen-binding defect in our system, although the mutant receptor was defective in transactivation assays. This mutation may affect an aspect of binding not tested, or may be part of a functional subdomain of the ligand-binding domain involved in transactivation. Overall we found milder mutations to be associated with milder clinical phenotypes. There is also clear evidence that phenotype is not solely dependent on androgen receptor function. Some of the mutant receptors were able to respond to high doses of androgen in vitro, suggesting that patients carrying these mutations may be the best candidates for androgen therapy. One such mutation is Ile869Met. A patient carrying this mutation has virilized spontaneously at puberty, so in vivo evidence agrees with the experimental result. Thus a more complete understanding of the functional consequences of androgen receptor mutations may provide a more rational basis for gender assignment in PAIS.

Amino Acid Sequence↗

PubMed1996

Expression of beta 3-adrenoceptor mRNA in rat tissues.

1. This study examines the expression of beta 3-adrenoceptor messenger RNA (beta 3-AR mRNA) in rat tissues to allow comparison with atypical beta-adrenoceptors determined by functional and radioligand binding techniques. 2. A reverse transcription/polymerase chain reaction protocol has been developed for determining the relative amounts of beta 3-AR mRNA in rat tissues. 3. Measurement of adipsin and uncoupling protein (UCP) mRNA was used to examine all tissues for the presence of white and brown adipose tissue which may contribute beta 3-AR mRNA. 4. The beta 3-AR mRNA is expressed at high levels in brown and white adipose tissue, stomach fundus, the longitudinal/circular smooth muscle of both colon and ileum, and colon submucosa. There was substantial expression of adipsin in colon submucosa and moderate expression in fundus, suggesting that in these regions at least some of the beta 3-AR signal may be contributed by fat. Pylorus and colon mucosa showed moderate levels of beta 3-AR mRNA with lower levels of adipsin. Ileum mucosa and submucosa showed low but readily detectable levels of beta 3-AR. 5. Expression of adipsin in rat skeletal muscles coupled to very low levels of beta 3-AR mRNA indicates that the observed beta 3-AR may be due to the presence of intrinsic fat. beta 3-AR mRNA was virtually undetectable in heart, lung and liver. These results raise the possibility that the atypical beta-AR demonstrated by functional and/or binding studies in muscle and in heart is not the beta 3-AR. 6. By use of two different sets of primers for amplification of beta 3-AR cDNA, no evidence was found for differential splicing of the mRNA in any of the tissues examined. 7. The detection of beta 3-AR mRNA in the gut mucosa and submucosa suggests that in addition to its established roles in lipolysis, thermogenesis and regulation of gut motility beta 3-AR may subserve other functions in the gastrointestinal tract. The absence of beta 3-AR mRNA in rat heart or its presence with adipsin in skeletal muscle suggests that atypical beta-adrenoceptor responses in heart and skeletal muscle are unlikely to be mediated by beta 3-AR.

Animals↗

PubMed1996

A new point mutation in the luteinising hormone receptor gene in familial and sporadic male limited precocious puberty: genotype does not always correlate with phenotype.

Genomic DNA from two families with male limited precocious puberty was examined for mutations of the LH receptor gene. In family 1, several members of the pedigree have FMPP, whereas in family 2 there is only one affected subject. A point mutation (T --> C at nucleotide 1192) resulting in substitution of threonine for methionine 398 in the second transmembrane domain of the LH receptor protein was found in both families. In addition, one member of family 1 has the mutation, but no evidence of precocious puberty. All obligate carriers within this family were shown to have the mutation, and it was not detected in 94 chromosomes from unaffected and unrelated white subjects. In family 2, the index case was the only one to have the mutation. A previously unreported neutral dimorphism (C --> T at nucleotide 1065) is also described.

Base Sequence↗

PubMed1995

Erythropoietin gene expression in fetal and adult sheep kidney.

The exact location of the cells which express erythropoietin (Epo) in the kidney is still controversial, with conflicting reports suggesting that both peritubular interstitial cells or proximal tubular epithelial cells are possible sites of Epo expression. In the present study we have examined the location of Epo-expressing cells in fetal and adult sheep kidneys after Epo expression was stimulated by anaemia. In situ hybridization histochemistry was performed using synthetic oligonucleotide probes complementary to part of the sheep Epo cDNA sequence or a riboprobe (cRNA) for ovine Epo of 520 bases. Epo expression was confined to peritubular cells of the kidney cortex, in general in the area close to the cortico-medullary junction. In some severely anaemic adult sheep kidneys, Epo-expressing cells were also found in the outer cortex. In addition we located Epo-expressing cells in the kidneys not only of anaemic fetuses (89-140 d of gestation, term = 150d) but also in kidneys from normal fetuses 60-110d of gestation. Again, Epo expression was seen only in peritubular cells of the kidney cortex. These findings confirm that the kidney is an important site of Epo production, in the sheep, from at least 0.4 gestation, but also show that there is no ontogenic change in the cellular site of production within the kidney.

Animals↗

PubMed1995

Expression of beta 3-adrenoceptor mRNA in rat brain.

The reverse transcription/polymerase chain reaction was used to demonstrate beta 3-adrenoceptor mRNA in rat brain regions. Levels were highest in hippocampus, cerebral cortex and striatum and lower in hypothalamus, brainstem and cerebellum.

Animals↗

PubMed1995

Trends in female sexual behaviour and sexually transmitted diseases in London, 1982-1992.

OBJECTIVE: To measure changes in female sexual behaviour, including condom use, and their relationship with the incidence of sexually transmitted and other genital diseases in women during the decade 1982-92. DESIGN: A prospective series of cross-sectional surveys of sexual behaviour reported by a standardised self-administered questionnaire in new patients who presented for screening and diagnosis. SETTING: A genitourinary medicine clinic in West London. SUBJECTS: 4089 consecutive newly attending patients who completed sexual behaviour questionnaires during 1982, 1987, 1989 and 1992. MAIN OUTCOME MEASURES: Trends in socio-demographic status, sexual behaviour, condom-use, sexually transmitted diseases and other genital infections diagnosed by routine clinical and laboratory methods. RESULTS: Women reported significantly increasing condom use (from 3.6% to 20.7%) and decreasing oral contraception (from 51.2% to 40.1%), but the proportion who used no contraception (23.6% to 24.7%) and the proportion who had never been pregnant (58.3% to 59.9%) remained similar. Numbers of sexual partners in the preceding year decreased (p < 0.001) and an increasing proportion of women practised oral intercourse (p < 0.001). During the same period, there was a progressive decline (p < 0.001) in the incidence of gonorrhoea, chlamydial infection and trichomoniasis by approximately two-thirds. However, the incidence of vaginal candidosis (p < 0.001), bacterial vaginosis (p < 0.001) and genital warts (p < 0.01) increased. CONCLUSIONS: Increasing use of condoms for vaginal intercourse with both regular and non-regular partners has been associated with a decrease in the incidence of gonorrhoea, chlamydial infection and trichomoniasis. There was also an increase in the practice of fellatio and a change in the spectrum of STD and other genital infections with little net reduction in morbidity. HIV infection showed no evidence of heterosexual spread.

Adolescent↗

PubMed1995

Heterosexual relationships and condom-use in the spread of sexually transmitted diseases to women.

OBJECTIVES: To examine the effect of patient-defined non-regular heterosexual relationships on the incidence of sexually transmitted diseases and other genital infections in women and the role of condom use in the prevention of their spread. DESIGN: A cross-sectional study of sexual behaviour reported by a standardised self-administered questionnaire in new patients who presented for screening and diagnosis. SETTING: A genitourinary medicine clinic in West London. SUBJECTS: 938 consecutive newly attending women who completed a sexual behaviour questionnaire in 1992. MAIN OUTCOME MEASURES: Variables relating to socio-demographic status, sexual behaviour, condom use, sexually transmitted diseases and other genital infections stratified by the reporting of non-regular partners. RESULTS: We found that women who reported non-regular sexual partners were more likely to be single (p = 0.0001), white (p < 0.0001), have had coitarche before 17 years of age (p = 0.003) and many more sexual partners both in the last year and in their life-time (p < 0.0001) and were more likely to practise fellatio (p < 0.0001), anal penetration (p = 0.004) and to be smokers (p < 0.0001). Paradoxically, the incidence of sexually transmitted diseases and other genital infections was no higher in this group than in the group of women who did not have non-regular partners. Increasing condom use with regular partners correlated with decreasing incidence of gonorrhoea (p < 0.001), chlamydial infection (p < 0.01) and trichomoniasis (p < 0.02), but increasing condom use with non-regular partners did not show this trend. CONCLUSIONS: Regular heterosexual partners play the major role in transmission of bacterial sexually transmitted diseases to women. This is significantly influenced by use of condoms.

Adolescent↗

PubMed1995

Inhibition of 5 alpha-reductase in genital skin fibroblasts and prostate tissue by dietary lignans and isoflavonoids.

Isoflavonoids and lignans, constituents of many plant foods, have been proposed as protective agents in those populations with a low incidence of hormone-dependent cancers. They may act by their inhibition of the metabolism of growth-promoting steroid hormones. This report describes the inhibition of 5 alpha-reductase and 17 beta-hydroxysteroid dehydrogenase by six isoflavonoids and two lignans in human genital skin fibroblast monolayers and homogenates, and in benign prostatic hyperplasia tissue homogenates. In genital skin fibroblasts, genistein, biochanin A and equol were the most potent inhibitors of 5 alpha-reductase activity, each resulting in greater than 80% inhibition at a concentration of 100 microM. The IC50 values for genistein and a seven-compound mixture were approximately 35 microM and 20 microM (2.9 microM of each compound) respectively. Of the lignans, enterolactone was the most potent inhibitor. Inhibition by biochanin A was shown to be reversible. When genital skin fibroblast homogenates were used, biochanin A was found to inhibit 5 alpha-reductase isozymes 1 and 2 to differing extents (30% and 75% respectively). Genistein was shown to inhibit 5 alpha-reductase 2 in a non-competitive nature (Vmax and Km values without and with inhibitor were 30 and 20 pmol/mg protein per h and 177 and 170 nM respectively). All of the compounds tested inhibited 17 beta-hydroxysteroid dehydrogenase activity in genital skin fibroblast monolayers. When prostate tissue homogenates were used, the compounds tested were better inhibitors of 5 alpha-reductase 1 than 2.(ABSTRACT TRUNCATED AT 250 WORDS)

17-Hydroxysteroid Dehydrogenases↗

PubMed1994

Transient ischemic attack and minor ischemic stroke: an algorithm for evaluation and treatment. Mayo Clinic Division of Cerebrovascular Diseases.

OBJECTIVE: To report a cost-effective and scientifically based algorithm for the clinical assessment and treatment of patients with transient ischemic attack (TIA) or minor ischemic stroke. DESIGN: We comprehensively reviewed the literature on the epidemiologic features, assessment approaches, and treatment recommendations for ischemic cerebrovascular disease and developed an algorithm by using the available clinical and research data to support all decision-making steps. MATERIAL AND METHODS: For patients with TIA or minor ischemic stroke, the appropriate setting for investigation (inpatient or outpatient), suggested diagnostic tests, use of anticoagulants and antiplatelet agents, and indications for surgical treatment are reviewed. RESULTS: Although stroke is a common cause of death and lost productivity in the United States, the clinical assessment of patients with TIA or minor ischemic stroke has lacked consistency. The simplified algorithm clarifies patients who may be candidates for hospitalization and possible anticoagulation therapy. Initial diagnostic studies should include computed tomography of the head without use of a contrast agent, which quickly distinguishes nonhemorrhagic from hemorrhagic cerebrovascular disease. Evolving noninvasive studies of the cerebral vasculature are providing increasingly sensitive means of detecting stenoses, yet cerebral angiography remains the "gold standard." Treatment options depend on the pathophysiologic findings on diagnostic evaluation. CONCLUSION: The assessment of patients with ischemic cerebrovascular disease is complex. The simplified algorithmic approach reported herein necessitates entry of appropriate patients into the algorithm. Because of clinical heterogeneity, an algorithm may apply to a wide spectrum of patients but will not cover every situation; hence, evaluation must be guided by a patient's unique history and findings on examination and by the physician's clinical experience.

Algorithms↗

PubMed1994

Factors affecting survival and occurrence of stroke in patients with transient ischemic attacks.

OBJECTIVE: To assess the predictive value of a series of demographic and clinical variables for stroke and survival in a population after a first transient ischemic attack (TIA). DESIGN: Cox proportional hazards regression analysis was used to determine the association of various demographic and clinical factors with survival and stroke in 330 residents of Rochester, Minnesota, who had an initial TIA with first medical attention within 120 days during the period 1955 through 1979. MATERIAL AND METHODS: We investigated several demographic, diagnostic, and treatment variables, including initial clinical manifestations (pure sensory TIA and unilateral carotid hemispheric TIA), to estimate the significant (P < or = 0.01) predictors of survival and of stroke. Follow-up was limited to 10 years. RESULTS: Relative survival for patients with a first TIA was 94% at 1 year and 87% at 5 years after first medical attention. Three interactions were significant predictors of survival: (1) age at TIA and gender (young women had the best survival and older women had the worst survival), (2) systolic blood pressure and congestive heart failure (patients with low systolic blood pressure and congestive heart failure had the worst survival), and (3) calendar year of onset and diabetes mellitus (survival was worst for patients with diabetes during the early years of the study). Only age was a significant independent predictor of stroke after TIA (hazards ratio, 1.45 per 10 years). CONCLUSIONS: Estimating risks of stroke and death after TIA on the basis of demographic and clinical variables without reference to the mechanism of TIA is of limited clinical utility. Age is the most significant such predictor. Interactions that reflect comorbidity, such as diabetes, blood pressure abnormalities, or heart disease, may affect survival but not the risk for occurrence of stroke.

Adult↗