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Biomedical subjects

A Donnelly

Publications and source records attributed to A Donnelly.

At least 37 records · Page 2Linked to original sources
PubMed1995

FRAXE and mental retardation.

Mental impairment and instability of the CCG repeat at FRAXE is described in six kindreds. Cosegregation of FRAXA and FRAXE was found within one of these kindreds. Cytogenetic expression of FRAXE was shown to skip a generation when associated with a reduction in size of the CCG expansion when transmitted through a male; however, in general, transmission occurred through females and a copy number increased from one generation to the next. In these respects the behaviour of FRAXE paralleled that of FRAXA. A relationship between FRAXE and non-specific mental impairment is strongly suggested by the occurrence in these families of more mentally impaired male and female carriers, after removal of index cases, than could reasonably be expected by chance.

Adolescent↗
PubMed1994

Localisation of the gene for X-linked reticulate pigmentary disorder with systemic manifestations (PDR), previously known as X-linked cutaneous amyloidosis.

X-linked reticulate pigmentary disorder (PDR), previously reported as X-linked cutaneous amyloidosis (MIM#301220), is characterized by brown pigmentation of the skin which follows the lines of Blaschko in females but appears as reticulate sheets in males. Males may suffer severe gastrointestinal disorders in infancy with failure to thrive and early death. Nowadays symptomatic treatment allows survival and other manifestations may appear such as corneal dystrophy with severe photophobia or chronic respiratory disease. Amyloid deposition in the skin may be no more than an age-dependent secondary manifestation. The PDR gene was localised by linkage analysis to Xp21-p22. The background genetic map is Xpter-DXS996-22.5-DXS207-3.3-DXS999-3.3-DXS36 5-14.2-DXS989-4.1-3'DMD-3.5- DXS997-1.0-STR44-9.3-DYSI-2.3-DXS1068-11.0-DX S228 with distances between markers given in cM. Recombinants detected with DXS999 distally and DXS228 proximally, define the limits to the localisation. Linkage was found with several markers within this interval. Peak lod scores of 3.21 at theta = 0.0 were obtained between PDR and DXS989 and between PDR and 5'DYSI within the dystrophin locus.

Amyloidosis↗
PubMed1994

A linkage map of microsatellite markers on the human X chromosome.

The efficiency of mapping and diagnosis of X-linked disorders by linkage depends upon the existence of a high-density genetic map of polymerase chain reaction (PCR)-based markers. DXS1120, DXS1122, DXS1123, DXS1124, DXS1125, DXS1126, and DXS1153 were randomly isolated from a flow-sorted lambda bacteriophage library of the human X chromosome. The CCN (N = A or G) repeat within the androgen receptor was also found to be polymorphic and primers were designed for genotyping the CCN polymorphism in addition to the AGC polymorphism. The above markers, together with microsatellite polymorphisms at DXS237 (GMGX9), 5'DYS-II and 3'DYS MS (within the dystrophin locus), DXS538 (XL27B), PGK1P1, DXS300 (VK29AC), DXS294 (VK17AC), and DXS102 (cX38.1AC), were genotyped in the 40 CEPH reference families. One marker, DXS1153, was found to include cryptic alleles that amplify only in homozygotes and hemizygotes but not heterozygotes. A PCR-based linkage map was constructed using all of the above markers plus PCR-based markers from the CEPH database and those PCR-based markers previously typed in our laboratory: ALAS2, DXS292 (VK14AC), DXS297 (VK23AC), FRAXAC1, and FRAXAC2. The genetic map of the X chromosome incorporates 62 PCR-based marker loci, integrates the Weissenbach markers, and extends from XG near Xpter to DXS52 near Xqter, a distance of 236 cM.

Alleles↗
PubMed1993

Nedocromil sodium is rapidly effective in the therapy of seasonal allergic rhinitis.

BACKGROUND: Nedocromil sodium has proven to be efficacious in prophylactic and long-term therapy for the treatment of seasonal allergic rhinitis. We examined the speed of onset of intranasal nedocromil sodium (1%) for relief of symptoms due to ragweed allergic rhinitis. METHODS: In a double-blind, placebo-controlled trial, 104 patients received either nedocromil sodium or placebo four times daily. Patients spent 10 hours per day for 2 consecutive days in Iowa City Park during the peak of ragweed season. Only patients who had significant symptoms during 3 hourly baseline assessments received drug. Symptom scores for stuffy nose, runny nose, itchy nose, and sneezing and global symptom summary scores were recorded at 19 hourly time points during the 2 days. In the evening patients recorded symptom scores for the postexposure period. RESULTS: In comparison with placebo, nedocromil significantly improved rhinitis symptoms as evidenced by lower symptom summary scores within 2 hours (p = 0.016). Further, this reduction in rhinitis symptoms was maintained throughout the 2-day pollen exposure period. After patients left the study site, postexposure symptom summary scores were also significantly lower in patients treated with nedocromil compared with those treated with placebo (p < 0.007). CONCLUSIONS: Nedocromil significantly relieved preexisting seasonal allergic rhinitis symptoms during peak pollen exposures within 2 hours of the first dose, and the therapeutic benefits were maintained on a dosing regimen of four times a day.

Adolescent↗
PubMed1993

Direct molecular diagnosis of myotonic dystrophy.

Myotonic dystrophy (DM) arises from an unstable trinucleotide (CTGn) repeat sequence within the DM locus at 19q13.3. Twenty-three myotonic dystrophy families containing 205 persons with no symptoms, minimal manifestations, classic DM or congenital DM were investigated to validate the application of the pM10M6 probe to direct molecular diagnosis. Affected family members had been diagnosed clinically and the unaffected family members had been assigned carrier probabilities close to either zero or 100%, using closely linked flanking markers. Southern analysis identified all 89 DM gene carriers as having expansions of the unstable element. PstI detected all small expansions of the repeat sequence as easily seen discrete bands; but large expansions were usually seen as diffuse smears, sometimes difficult to distinguish from lane background. EcoRI concentrated these diffuse smears, associated with somatic instability, into discrete bands which were easy to detect; but it did not resolve the smaller expansions present in 9 (10%) of the DM carriers. It is essential that PstI and EcoRI gels are run in parallel to detect all DM gene carriers. The extent of expansion of CTG correlated with age of onset and disease severity. Biopsies of various fetal tissues from two terminated pregnancies confirmed the diagnosis obtained by CVS and revealed no heterogeneity between tissues at this developmental stage. Further expansion occurred during the culture of CVS cells, indicating that direct prenatal diagnosis needs to be carried out on CVS tissue rather than on cultured cells. The intergenerational change of the repeat sequence from DM parent to DM offspring showed a significant parental sex difference for those parents with large expansions. Contraction of the unstable element was observed in the three males carrying the largest expansions and could explain why congenital DM is exclusively of maternal origin.

Female↗
PubMed1992

Experience with direct molecular diagnosis of fragile X.

The utility of the pfxa3 probe for direct molecular diagnosis of the fragile X (FRAXA) has been established. This probe detects amplification of an unstable DNA element consisting of variable length CCG repeats. The size of the amplified fragment is correlated with phenotype and was determined using PstI digested DNA in family members. In 35 families with the fragile X, there was correspondence in 183 cases between the presence of an amplified unstable element and the presence of the fragile X chromosome independently determined by cytogenetics, position in the pedigree, or linked DNA markers flanking the fragile X. There was also correspondence in 124 cases between the presence of the normal 1.0 kb PstI fragment and absence of the fragile X chromosome independently determined by linked flanking markers. Six additional families considered to be isolated cases of 'fragile X' had been diagnosed before recognition of FRAXD. The pfxa3 probe confirmed the cytogenetic diagnosis in three families, the other three being rediagnosed as non-fragile X. A further two families had consistent expression of a different folate sensitive fragile site, FRAXE, close to FRAXA but not associated with fragile X syndrome and not detectable with the pfxa3 probe. Subsequent referrals were received from additional family members or from members of new families for whom carrier status had not been predetermined by linked markers. Direct pfxa3 diagnosis for the 135 females within these 222 additional cases was confirmed by dosage analysis with the control probe pS8.(ABSTRACT TRUNCATED AT 250 WORDS)

Artifacts↗
PubMed1992

Reversal of ethanol-induced respiratory depression by flumazenil.

Flumazenil is effective in reversing sedation resulting from benzodiazepine (BZD) toxicity. Its use for other causes of sedation have not been well described. A 23-y-old male was found unconscious. Upon being aroused, the patient stated he had recently ingested 1 1/2 bottles of vodka/beer and 250 mg of diazepam. Physical examination revealed shallow breathing and respiratory depression. Arterial blood gases were consistent with the clinical diagnosis of respiratory depression (pH 7.34, pCO2 47, pO2 99). However, after receiving 3 mg of flumazenil, the respiratory depression improved so that the patient no longer required intubation. The drug screen returned negative for BZDs and the patient had a blood alcohol level of 332 mg/dl. He later denied BZD use. The patient's clinical course improved throughout the study period, and mechanical ventilation was avoided. This report reflects a possible role for flumazenil in reversing the respiratory depression produced by ethanol ingestion.

Adult↗
PubMed1992

Fragile-X syndrome: unique genetics of the heritable unstable element.

The fragile site at Xq27.3 is an unstable microsatellite repeat, p(CCG)n. In fragile-X syndrome pedigrees, this sequence exhibits variable amplification, the length of which correlates with fragile-site expression. There is a direct relationship between increased p(CCG)n copy number and propensity for instability: individuals having large amplifications exhibit somatic variation due to increased instability. The instability of the p(CCG)n repeat, when transmitted through affected pedigrees, explains the unusual segregation patterns of fragile-X phenotype, referred to as the Sherman paradox. All individuals of fragile-X genotype were found (where testing was possible) to have a parent with amplified p(CCG)n repeat, indicating that few, if any, cases of fragile-X syndrome are not familial.

Blotting, Southern↗
PubMed1990

Randomized, double-blind, parallel groups, placebo-controlled study of efficacy and safety of Rynatan in the treatment of allergic rhinitis using an acute model.

We conducted a randomized, double-blind, parallel groups, placebo-controlled acute study of Rynatan (8 mg chlorpheniramine tannate, 25 mg pyrilamine tannate, 25 mg phenylephrine tannate) in 104 volunteers with allergic rhinitis. Subjects reported to City Park on a Saturday morning during the height of the grass pollen season in late spring and remained in the park for eight hours that day and on the following day. Cards were completed hourly to evaluate symptoms of allergic rhinitis and adverse experiences caused by therapy. The first three cards completed on Saturday morning were used to demonstrate that each subject had had at least minimal symptoms of allergic rhinitis and to determine baseline symptoms. Rynatan or placebo was given at noon and 7:30 PM that day and at 8:30 AM the next day. Subjects completed symptom cards hourly until 4:30 PM on Saturday, three cards that evening, and eight cards hourly the next day until 4:30 PM. The group receiving Rynatan had significantly more allergic rhinitis symptom relief than the placebo group (P = .003). More subjects in the Rynatan group (34/52) reported global symptom improvement than did subjects in the placebo group (18/52, P = .002). There were no significant severe adverse experiences and no statistically significant differences between treatment groups in incidence or severity of drowsiness, dizziness, jitteriness, headache, or nausea. We conclude that Rynatan is safe and effective in treating acute symptoms of allergic rhinitis in otherwise healthy adult subjects.

Adolescent↗
PubMed1988

Multicenter, double-blind, multiple-dose, parallel-groups efficacy and safety trial of azelastine, chlorpheniramine, and placebo in the treatment of spring allergic rhinitis.

Azelastine, a novel antiallergic medication, was compared with chlorpheniramine maleate and placebo for efficacy and safety in the treatment of spring allergic rhinitis in a multicenter, double-blind, multiple-dose, parallel-groups study. One hundred fifty-five subjects participated. Subjects ranged in age from 18 to 60 years of age and had at least a 2-year history of spring allergic rhinitis, confirmed by positive skin test to spring aeroallergens. Medications were given four times daily; the azelastine groups received 0.5, 1.0, or 2.0 mg in the morning and evening with placebo in the early and late afternoon; the chlorpheniramine group received 4.0 mg four times daily. Daily subject symptom cards were completed during a screening period to assess pretreatment symptoms and during a 4-week treatment period while subjects received study medications. Individual symptoms, total symptoms, and major symptoms were compared to determine efficacy of medication. Elicited, volunteered, and observed adverse experiences were recorded for each subject and compared among groups. Vital signs, body weights, serum chemistry values, complete blood cell counts, urine studies, and electrocardiograms were obtained for each subject and compared among groups. Symptoms relief in the group receiving the highest concentration of azelastine (2.0 mg twice daily) was statistically greater than in the placebo group during all weeks of the study. Lower doses of azelastine were statistically more effective than placebo only during portions of the first 3 weeks of the study. In contrast, although the chlorpheniramine group did have fewer symptoms than the placebo group during the study, the difference never reached statistical significance during any week of the study. There were no serious side effects in any of the treatment groups. Drowsiness and altered taste perception were increased significantly over placebo only in the high-dose azelastine group. Azelastine appears to be a safe, efficacious medication for seasonal allergic rhinitis.

Adolescent↗