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Biomedical subjects

A J Rowan

Publications and source records attributed to A J Rowan.

At least 37 records · Page 2Linked to original sources
PubMed1998

Tiagabine for complex partial seizures: a randomized, add-on, dose-response trial.

OBJECTIVE: To determine the efficacy and tolerability of tiagabine, a new antiepileptic drug (AED) that inhibits gamma-aminobutyric acid (GABA) uptake, at 3 dose levels vs placebo as adjunctive therapy in patients with intractable complex partial seizures (CPS). DESIGN: Randomized, double-blind, placebo-controlled study with a parallel-group, add-on design, starting with a 12-week unblinded baseline phase followed by a 20-week double-blind treatment phase. SETTING: Twenty-one US medical centers. PATIENTS: Patients (N = 297) aged 12 to 77 years, previously diagnosed as having CPS and receiving stable regimens of 1 to 3 hepatic enzyme-inducing AEDs; divalproex sodium or valproic acid was allowed in combination with any of these drugs. INTERVENTIONS: Placebo or tiagabine 4 times a day at 16, 32, or 56 mg daily. MAIN OUTCOME MEASURES: Median change in 4-week CPS frequency and adverse events. RESULTS: Median decreases in 4-week CPS frequency for the 32-mg (-2.2) and 56-mg (-2.8) tiagabine groups were significantly greater than for the placebo (-0.7) group (P = .03 and P < .03, respectively); 20% and 29% of patients in the 32- and 56-mg groups had a 50% or greater reduction in the frequency of CPS vs 4% in the placebo group (P = .002 and P < .001, respectively). Adverse effects were similar for placebo and tiagabine except for a significantly greater incidence of dizziness in the 32-mg tiagabine group, tremor in the 32- and 56-mg groups, abnormal thinking (usually mental lethargy or difficulty concentrating) in the 56-mg group, and depressed mood in the 16- and 56-mg groups. CONCLUSIONS: Tiagabine is efficacious and well tolerated as adjunctive therapy for CPS; there is a clear dose-response relationship.

Adolescent↗
PubMed1998

Reflections on the treatment of seizures in the elderly population.

Treatment of seizure disorders in older patients is an important problem because of the age-related increase in seizure incidence and the growing size of this segment of the population. Physiologic changes that occur with aging may influence drug dosing and safety. The standard antiepileptic drugs (AEDs) are not ideal for treating older patients because of their complex pharmacokinetics, multiple drug interactions, and possible increased susceptibility to adverse effects. Data are limited on the use of the newer AEDs--gabapentin, lamotrigine, topiramate, and tiagabine--in older patients. An ongoing clinical trial in this population is investigating the efficacy and safety of gabapentin and lamotrigine relative to carbamazepine for the treatment of new-onset partial seizures. Other trials are needed to evaluate the use of topiramate and tiagabine in older patients with epilepsy. In the absence of these data, AED selection in older patients must be made on the basis of current knowledge of efficacy and safety profiles. The newer agents now offer increased therapeutic options and some theoretical advantages over the older AEDs for elderly persons with seizures.

Adolescent↗
PubMed1997

Introduction of a myc reporter tag to improve the quality of mutation detection using the protein truncation test.

The protein truncation test is a useful method for identifying frameshift and nonsense mutations. The interpretation of real results is often made difficult by the presence of internally translated protein products and other nonspecific bands. To overcome these problems, the technique has been modified to include a myc reporter tag in the 5' primer used to amplify the genomic region of interest. The myc tag is recognised by a monoclonal antibody, which can be used to manipulate the products of the protein truncation test using immunoprecipitation techniques. The presence of the myc tag also introduces a mechanism whereby the use of radioisotopes can be avoided, relying instead on the identification of newly synthesised proteins using Western blot technology. The myc-tag modification can be integrated into all protein truncation tests, regardless of the gene being examined, with only one monoclonal antibody required for the immunoprecipitation purification and Western blotting.

Antibodies, Monoclonal↗
PubMed1995

Aspartame and seizure susceptibility: results of a clinical study in reportedly sensitive individuals.

The high intensity sweetener aspartame has been implicated anecdotally in seizure provocation. This possibility was investigated with a randomized, double-blind, placebo-controlled, cross-over study. After an extensive search, 18 individuals (16 adults and 2 children) who had seizures allegedly related to aspartame consumption were admitted to adult or pediatric epilepsy monitoring units where their EEG was monitored continuously for 5 days. Aspartame (50 mg/kg) or identically enpackaged placebo was administered in divided doses at 0800, 1000, and 1200 h on study days 2 and 4. All meals were uniformly standardized on treatment days. No clinical seizures or other adverse experiences were observed after aspartame ingestion. Mean plasma phenylalanine (Phe) concentrations increased significantly after aspartame ingestion (83.6 microM) as compared with placebo (52.3 microM). Results suggest that aspartame, in acute dosage of approximately 50 mg/kg, is no more likely than placebo to cause seizures in individuals who reported that their seizures were provoked by aspartame consumption.

Adolescent↗
PubMed1994

An epitope on carcinoembryonic antigen defined by the clinically relevant antibody PR1A3.

The monoclonal antibody PR1A3 has been used successfully for in vivo imaging of colorectal cancers, and several properties associated with this antibody, including minimal reactions of the antibody with circulating antigen in patients' sera, differentiate it from anti-carcinoembryonic antigen (CEA) antibodies used in similar studies. However, the antigen bound by PR1A3 was identified as CEA by analysis of somatic cell hybrids and by antigen expression from yeast artificial chromosomes, cosmids, and cDNA clones. The molecular weight, presence of a glycosyl-phosphatidylinositol anchor, elevation of surface expression by gamma-interferon, and N-terminal amino acid sequence all confirmed the antigen identification as CEA. A series of biliary glycoprotein-CEA hybrid proteins was produced which demonstrated that the epitope bound by the antibody was at the site of membrane attachment and involved parts of the glycosyl-phosphatidylinositol anchor and the B3 domain of CEA to form a conformational epitope. Access to this epitope, although possible when the antigen was on the cell surface, appeared to be blocked when CEA was released from the cell. The nature and location of the epitope on CEA are proposed to be responsible for the unique properties of the antibody.

Animals↗
PubMed1994

SCID diagnosis of panic disorder in psychogenic seizure patients.

The authors administered the Structured Clinic Interview for DSM-III-R (SCID) to 20 outpatients with nonepileptic seizures documented by video-EEG. Fourteen (70%) had one or more non-somatoform DSM-III-R diagnoses. All 14 met criteria for panic disorder. Comorbid mood, psychotic, substance abuse, and eating disorders were also noted. Meticulous use of the SCID, with extensive follow-up, may have resulted in enhanced detection of panic disorder in patients who do not spontaneously report panic symptoms. Panic attacks may play a more important role in nonepileptic seizures than has been generally recognized, especially in outpatients with a chronic course of illness.

Adult↗
PubMed1990

A comparative clinical trial of Norinyl 1 + 35 versus Norinyl 1 + 50 in Merida, Yucatan, Mexico.

A comparative clinical trial of two combined oral contraceptives differing only in estrogen type and dosage was conducted at the Centro de Investigaciones Hideyo Noguchi in Merida, Yucatan, Mexico. The trial was designed to determine the differences between Norinyl 1 + 50 (Syntex) and Norinyl 1 + 35 (Syntex) in rates of discontinuation and frequency of selected side-effects which might contribute to method discontinuation. Three hundred women were randomly assigned to either the Norinyl 1 + 35 group or to the Norinyl 1 + 50 group and follow-up visits were scheduled at 1, 4, 8 and 12 months after admission. In the Norinyl 1 + 35 group, more women experienced an increase in intermenstrual bleeding (primarily staining and spotting) (p less than 0.05), breast discomfort (p less than 0.05) and nausea than in the Norinyl 1 + 50 group. There was a significantly higher discontinuation rate for personal reasons, such as desired change of method and method not needed, among the women taking Norinyl 1 + 35 (p less than 0.05). The largest number of discontinuations comprised women discontinuing for menstrual problems in both groups. The life-table total discontinuation rate at 12 months was 52.0 for the Norinyl 1 + 35 group and 50.7 for the Norinyl 1 + 50 group. The lost-to-follow-up rates at 12 months were 17.8 for the Norinyl 1 + 35 group and 22.8 for the Norinyl 1 + 50 group.

Adolescent↗
PubMed1990

Supplementary motor seizures mimicking pseudoseizures: some clinical differences.

Supplementary motor seizures (SMS) are among the group of frontal lobe seizures that may often be misdiagnosed as pseudoseizures (PS). We designed this study to determine the value of clinical phenomena in distinguishing between the two. In a series of patients with SMS, we identified those with symptoms mimicking PS and compared the clinical phenomena with those of clinically similar PS. We found that SMS are short in duration, stereotypic, tend to occur in sleep, and often present with a tonic contraction of the upper extremities in abduction. This sign was specific for SMS, particularly when occurring at the onset. Conversely, PS are long in duration, nonstereotypic, and occur in the awake state. We conclude that clinical phenomena may be useful in distinguishing PS from SMS, although the final diagnosis must be documented by neurophysiologic means.

Diagnosis, Differential↗
PubMed1989

Characterisation of antibodies to urinary gonadotrophin peptide.

There is now general recognition that human chorionic gonadotropin (hCG), its beta subunit and its fragments are valuable diagnostic markers of trophoblastic and some non-trophoblastic malignancies. Urinary gonadotropin peptide (UGP) contains at least one epitope which cross-reacts with the beta-subunit of hCG. In order to assess the potential of UGP as a tumour marker in its own right, it was paramount that any measurements made could be regarded as specific for UGP and not cross-reactive with either hCG or human luteinising hormone (hLH). Four antibodies were tested, two polyclonal (AK12 and DR-Pool) and two monoclonal (2C2 and 6D3). Initial screening using radioiodinated (125I) UGP, hCG, hCG beta-subunit and hLH showed that the polyclonal antibodies bound to all four gonadotrophins, whilst the monoclonal antibodies bound only to the radioiodinated UGP. The antibodies were tested in both radioimmunoassay (RIA) and immunoradiometric assay (IRMA-sandwich assay) systems. The parameters measured were sensitivity and specificity for UGP. The polyclonal antibodies used in the RIA system produced a sensitive assay (0.2 ng/ml UGP) which was relatively specific; cross-reactions for the AK12 antibody (at 50% inhibition) were 5% for hCG, 11% for its beta-subunit, 0.4% for the alpha-subunit and 2.6% for hLH. The monoclonal antibodies performed optimally in the IRMA system. Immobilised 2C2 and radiolabelled (125I) AK12 produced a system that had a sensitivity of 0.4 ng/ml UGP and cross-reactivity (50% maximum binding) of 2% for the hCG beta-subunit and less than 1% for hCG, hLH and the hCG alpha-subunit.

Antibody Specificity↗
PubMed1989

Genetic analysis of colorectal cancer.

Adenomatous polyposis, mainly of the colon, (APC) is a rare dominantly inherited susceptibility to colon cancer in which individuals develop hundreds of polyps mainly in their large bowel. The APC gene has been localised to chromosome 5q21 by following up a case report of an individual with an interstitial deletion on chromosome 5q who had multiple developmental abnormalities together with adenomatous polyposis. A DNA marker (D5S71) was found to be closely linked to APC in family studies and localised to 5q21 by in situ annealing. Material from further patients with deletions in this region of chromosome 5 has been used, by a combination of somatic cell hybrid and long-range DNA analysis, to identify new DNA markers close to the APC gene. These and other markers now provide the basis for genetic counselling of nearly all families with APC. These studies are being extended, together with other approaches for analysing DNA clones around the APC gene, in the search for the gene itself. Allele loss in tumour as compared to normal tissue from sporadic cases of colorectal carcinomas has clearly implicated the APC gene in at least 25 to 40% of all cases of colorectal carcinomas. Similar studies by Vogelstein and others as well as ourselves have further implicated recessive changes on chromosomes 17 and 18 in the development of colorectal carcinomas. Following the demonstration by Vogelstein of the role of p53 mutations in connection with the chromosome 17 changes, we have now shown, using monoclonal antibodies to the mutant p53 products and by other approaches, that changes in the p53 gene may occur in up to 50% or more of colorectal carcinomas. Frequent mutations of the K-ras dominant oncogene, as well as changes in the expression of human leucocyte antigen (HLA)-A, B, C determinants, are further genetic changes that appear commonly to be involved in the progression of colorectal carcinomas. The latter have important implications for T cell immune response to tumours and its manipulation for treatment and even prevention of colorectal cancer. We may soon be approaching a situation when it will become possible to identify all the genetic steps and their sequence during tumour progression, as well as their functional significance largely through the induction of inappropriate growth and the suppression of differentiation.

Adenomatous Polyposis Coli↗
PubMed1988

A comparative clinical trial of Norinyl 1/35 versus Brevicon in Rio Clara, Brazil.

A comparative clinical trial of two combined oral contraceptives (OCs) with equivalent estrogen content, but different amounts of progestogens, was conducted at the Centro Medico Especializado em Planejamento Familiar in Rio Clara, Brazil. The study was designed to determine the differences in discontinuation rates between Norinyl 1/35 (Syntex) and Brevicon (Syntex) as well as the frequency of selected side effects which might contribute to method discontinuation. Both OCs contain 0.035 mg of ethinyl estradiol; Brevicon contains 0.5 mg and Norinyl 1/35 contains 1 mg norethindrone. Three-hundred women enrolled in the study were randomly assigned to either the Norinyl 1/35 or Brevicon OCs and follow-up visits were scheduled at 1, 4, 8 and 12 months after admission. Intermenstrual bleeding was reported by significantly more women in the Brevicon group than in the Norinyl group (p less than 0.05), and significantly more Brevicon users reported an increase in intermenstrual bleeding. At the end of the study period, no differences were found between the two OC groups in terms of discontinuation rates, but a large number of women in each group discontinued for menstrual problems. The total discontinuation rates at 11 months for both groups were extremely high: 68.2 for the Norinyl 1/35 group and 75.2 for the Brevicon users. The largest group of discontinuations were comprised of those discontinuing for menstrual problems, other personal reasons, planned pregnancy and side effects.

Adult↗
PubMed1988

Transient aphasic episodes due to hypoglycemia.

A 58-year-old diabetic man suffered two episodes of hypoglycemia accompanied by isolated aphasia. Prompt resolution of the language disorder followed treatment with 50% glucose IV. The day following the first event the EEG demonstrated bitemporal delta activity, more prominent over the left hemisphere. EEG repeated two weeks after the second event showed residual left temporal slowing. The differential diagnosis between hypoglycemia and transient ischemic attacks in diabetic patients presenting with transient focal neurological deficit is emphasized.

Anomia↗
PubMed1988

Urinary gonadotrophin peptide--isolation and purification, and its immunohistochemical distribution in normal and neoplastic tissues.

A urinary gonadotrophin peptide (UGP) was isolated and purified from semi-purified human chorionic gonadotrophin (hCG), prepared from pregnancy urine. The peptide showed hCG-B subunit activity and no hCG-alpha subunit activity as demonstrated by binding studies with the relevant antibodies. It had a molecular weight significantly less than hCG-B subunit. The peptide was linked to thyroglobulin and this conjugate used to immunise rabbits and mice. A radioimmunoassay (RIA) using 125I-UGP and the rabbit antiserum (AK12) was used to monitor chromatographed urine fractions from patients with ovarian carcinoma, seminoma and hydatidiform mole. UGP was also found in the urine extract of a healthy male, but at a much lower level. In each case the UGP detected had the same molecular weight as the pregnancy preparation and appeared to be the main gonadotrophin constituent in those urine samples. Initial immunohistochemical screening of normal and neoplastic tissues with the rabbit antibody (AK12) showed reactivity with some tumours including carcinomas of the lung, ovary, cervix and breast as well as trophoblastic and germ cell tumours. Reactions with non-neoplastic tissues were confined to some specialised epithelia and macrophage populations. A more comprehensive immunohistochemical study was made using a monoclonal antibody to UGP (2C2), with a monoclonal antibody to conformational hCG (INN 13) and another monoclonal antibody to free B subunit (1E5) as controls. Similar patterns of reactivity were produced by the AK12 and 2C2 antibodies in both neoplastic and non-neoplastic tissues. Additional tissues were investigated with the three monoclonal antibodies. The 2C2 antibody reacted with 93% (77/83) of tumours examined; the INN 13 antibody reacted with only the syncytiotrophoblast cells of choriocarcinoma, hydatidiform mole, placental site trophoblastic tumour, and in one case of seminoma; the 1E5 reactivity was confined to only choriocarcinoma syncytiotrophoblast cells.

Chorionic Gonadotropin↗
PubMed1987

A comparative study of Norinyl 1/35 versus Norinyl 1/50 in Belgrade, Yugoslavia.

A comparative study of Norinyl 1/35 and Norinyl 1/50 was conducted at the Dom Zdravlja Stari Grad in Belgrade, Yugoslavia. The study sought to evaluate the differences in continuation rates as well as the frequency of selected side effects which might contribute to method discontinuation. The trial included 299 women who were randomly allocated to one of the two oral contraceptives. In the Norinyl 1/35 group, significantly more women (p less than .05) reported a complaint of vaginal discharge as well as an increase in the occurrence of vaginal discharge compared to the Norinyl 1/50 group. There was no significant difference in continuation rates or for particular discontinuation reasons for the Norinyl 1/35 and Norinyl 1/50 groups. No accidental pregnancies were reported during this study. Both oral contraceptives appear to be safe and effective; there appears to be no difference in the acceptability of one oral contraceptive over the other among this group of Yugoslavian women.

Adult↗
PubMed1987

A comparative study of Norinyl 1/35 versus Brevicon in Panama City, Panama.

A comparative study of Norinyl 1/35 and Brevicon was conducted at the APLAFA clinic in Panama City, Panama. The study sought to evaluate the differences in continuation rates and the frequency of selected side effects which might contribute to method discontinuation. The 300 subjects were randomly allocated to one of the two oral contraceptives. Women in the Brevicon group reported significantly more (p less than 0.05) intermenstrual bleeding, nausea, headaches, dizziness and vaginal discharge than women in the Norinyl 1/35 group. The total discontinuation rate at 12 months was 28.0 for the Norinyl 1/35 group and 46.7 for the Brevicon group, and this difference was significant (p less than .01). Also, significantly more women (p less than .01) in the Brevicon group discontinued for menstrual problems than women in the Norinyl 1/35 group. No pregnancies were reported during this study. While both oral contraceptives appear safe and effective, Norinyl 1/35 was more acceptable to this group of Panamanian women.

Actuarial Analysis↗
PubMed1987

Clinical and EEG prediction of seizure recurrence following antiepileptic drug withdrawal.

A prospective study is reported of antiepileptic drug withdrawal in 62 neurologically intact adult patients who had become seizure-free at least 3 years previously. No single clinical or laboratory finding was reliably predictive of outcome and in particular the presence of epileptiform EEG activity prior to AED withdrawal or appearance of such activity during withdrawal was not associated with relapse. A multivariate model was however developed which suggested that patients capable of remaining seizure-free without medication could be reliably identified at a much reduced cost of relapses in the remainder.

Adolescent↗