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J A Dickson

Publications and source records attributed to J A Dickson.

At least 19 recordsLinked to original sources
PubMed1999

Assessment of clinical case presentations for the Membership in Orthodontics, Royal College of Surgeons of England 1995, 1996.

The cases presented and treated at successive examinations by the candidates for the Membership Examination in Orthodontics in 1995 and 1996 at The Royal College of Surgeons of England, were of a very high standard and demonstrated a wide range of treatment modalities. All cases had fixed appliances, predominantly with pre-adjusted Edgewise appliances. IOTN confirmed that most cases were in great need of treatment, with PAR scores showing them to be treated to a high standard.

Dental Records↗
PubMed1997

Unstimulated immature oocyte retrieval: early versus midfollicular endometrial priming.

OBJECTIVE: To assess the ability to retrieve transvaginally unstimulated immature oocytes from assisted reproductive technology (ART) patients and to determine their competency to mature, fertilize, and implant with early versus midfollicular exogenous estrogen endometrial priming. DESIGN: Prospective randomized study. SETTING: In vitro fertilization unit, private reproductive endocrinology and infertility practice. PATIENT(S): Fourteen patients, all had failed at least one IVF cycle. INTERVENTION(S): Early follicular endometrial priming was initiated on cycle day 3 with 2 mg 17 beta-E2 twice per day (group A). Midfollicular endometrial priming was initiated with 1 to 2 mg/d of 17 beta-E2 between cycle days 5 and 7 and gradually increased by 1 to 2 mg/d until the oocyte retrieval (group B). The oocytes were allowed to mature in 0.075 IU FSH or hMG, 0.5 IU of hCG, 1 microgram of 17 beta-E2 in Eagle's or Tissue Culture Media 199, fertilized, and transferred 72 hours later. MAIN OUTCOME MEASURE(S): Maturation, fertilization, and pregnancy rate. RESULT(S): Group A patients had 83 oocytes retrieved (11.8 +/- 6.1) versus 78 oocytes (11.1 +/- 2.7) from group B. The maturation rate in group A was 39.7% (34/83) versus 61.5% (48/78) in group B. The fertilization rate was 75.7% (25/34) in group A versus 75.0% (36/48) in group B. The cleavage arrest rate was significantly higher, 36.0% (9/25) in group A versus 8.3% (3/ 36) in group B. The number of embryos transferred was 1.8 embryos per retrieval in group A versus 4.0 embryos per retrieval in group B. One pregnancy was established in a patient with tubal disease in group B who delivered at 36 weeks gestation. CONCLUSION(S): Unstimulated immature oocyte retrieval can be performed successfully in ART patients. Midfollicular endometrial priming was able to achieve successful maturation (60%), fertilization (75%), and cleavage (92%), with the delivery of a successful pregnancy.

Adult↗
PubMed1996

Ultrasound compared with clinical examination in infantile hypertrophic pyloric stenosis.

OBJECTIVES: To assess the accuracy of clinical examination as compared with ultrasound imaging in the diagnosis of infantile hypertrophic pyloric stenosis. Duration of hospital stay, time between admission and surgery, and financial implications were also considered. DESIGN: A prospective study of patients referred to the surgical team with a possible diagnosis of pyloric stenosis from May 1993 to January 1995. SETTING: Neonatal and paediatric surgical wards and imaging department of a paediatric teaching hospital. SUBJECTS: 116 patients referred to the surgical team with a possible diagnosis of pyloric stenosis. RESULTS: 75 patients in this study had pyloric stenosis (64.6%). Clinical examination had a sensitivity of 72%, specificity of 97%, with a positive and negative predictive value of 98% and 61% respectively. There were 16 diagnostic errors (one false positive and 15 false negative). Ultrasound imaging had a sensitivity of 97%, specificity of 100%, with a positive and negative predictive value of 100% and 98% respectively. There was one diagnostic error (one false negative). Eight patients required repeat scans for confirmation of the diagnosis. On review of the initial scans in these patients, seven were noted to have inaccurate measurements due to poor technique. The average time between repeated scans was 28.2 hours. Ultrasound imaging cost 13.90 pounds per scan and initiated a change in management only in the clinically false negative group at a cost of 52 pounds per patient. The average duration of hospital stay was 3.1 days and the mean time between admission and surgery was 19.2 hours. The total cost for treatment of a patient with pyloric stenosis was 1602 pounds. CONCLUSION: Ultrasound imaging should be reserved for those cases where clinical examination is negative and should be carried out by sonographers who see enough cases to maintain their expertise.

Costs and Cost Analysis↗
PubMed1996

Antibiotic prophylaxis for infantile pyloromyotomy.

A retrospective study of 50 patients with infantile hypertrophic pyloric stenosis (IHPS) showed wound infection in six patients. In an attempt to assess the value of antibiotic prophylaxis in infantile pyloromyotomy 150 patients with infantile hypertrophic pyloric stenosis were entered in a prospective randomized controlled study. The infants were allocated to receive a dose of Cefuroxime (30 mg/kg) at induction of anaesthesia or no antibiotic. Eight infants developed wound infection, five in the control group and three in the antibiotic prophylaxis group. Although the difference between the two groups was not statistically significant there was an overall reduction of wound infection (6.5%) compared with pre-trial figures (12%). In order to study the bacterial flora in the umbilicus in these infants, culture swabs were taken from the umbilicus on admission, immediately prior to surgery and from the wound prior to skin closure. It was shown that the umbilicus was not the source of infection.

Antibiotic Prophylaxis↗
PubMed1995

Applied potential tomography in the measurement of gastric emptying in infants.

The aim of this study was to investigate the feasibility of using applied potential tomography (APT), a noninvasive and nonradioactive method, to measure the rate of gastric emptying in preterm babies and infants < 3 months old. APT, a form of electrical impedance tomography, creates tomographic images of tissue resistivity to a small electrical current and has been used to study gastric emptying in adults. The rate of gastric emptying of 53 preterm infants and 29 term infants was measured. The test feed was either milk (formula milk or expressed breast milk) or Dioralyte (a commercial rehydration solution). When a nasogastric tube was present, the results obtained by APT were validated by comparing the volume of feed estimated to be present with the volume that could be aspirated. All infants completed the investigation without any problems. APT demonstrated a slower rate of emptying of milk feeds than Dioralyte and showed that milk and Dioralyte feeds in preterm babies emptied at a similar rate to feeds in term infants. In validation studies, gastric emptying has been observed in 44 of 47 studies, and this finding was confirmed by aspiration of the nasogastric tube. Applied potential tomography is a safe, noninvasive method for measuring gastric emptying in small infants.

Bottle Feeding↗
PubMed1994

A comparison of the frictional characteristics of five initial alignment wires and stainless steel brackets at three bracket to wire angulations--an in vitro study.

The study investigated static planar frictional resistance between five initial alignment wires and stainless steel brackets at three bracket to wire angulations (0, 5 and 10 degrees). It was demonstrated that static frictional resistance increased significantly with increasing bracket to wire angulation due to binding within the system. Epoxy-coated steel had the highest static frictional resistance and coaxial stainless steel the lowest. Fibre-optic glass (Optiflex) had low frictional resistance. The coefficient of friction followed the trends of static frictional resistance in all respects.

Dental Alloys↗
PubMed1993

Human ERCC5 cDNA-cosmid complementation for excision repair and bipartite amino acid domains conserved with RAD proteins of Saccharomyces cerevisiae and Schizosaccharomyces pombe.

Several human genes related to DNA excision repair (ER) have been isolated via ER cross-species complementation (ERCC) of UV-sensitive CHO cells. We have now isolated and characterized cDNAs for the human ERCC5 gene that complement CHO UV135 cells. The ERCC5 mRNA size is about 4.6 kb. Our available cDNA clones are partial length, and no single clone was active for UV135 complementation. When cDNAs were mixed pairwise with a cosmid clone containing an overlapping 5'-end segment of the ERCC5 gene, DNA transfer produced UV-resistant colonies with 60 to 95% correction of UV resistance relative to either a genomic ERCC5 DNA transformant or the CHO AA8 progenitor cells. cDNA-cosmid transformants regained intermediate levels (20 to 45%) of ER-dependent reactivation of a UV-damaged pSVCATgpt reporter plasmid. Our evidence strongly implicates an in situ recombination mechanism in cDNA-cosmid complementation for ER. The complete deduced amino acid sequence of ERCC5 was reconstructed from several cDNA clones encoding a predicted protein of 1,186 amino acids. The ERCC5 protein has extensive sequence similarities, in bipartite domains A and B, to products of RAD repair genes of two yeasts, Saccharomyces cerevisiae RAD2 and Schizosaccharomyces pombe rad13. Sequence, structural, and functional data taken together indicate that ERCC5 and its relatives are probable functional homologs. A second locus represented by S. cerevisiae YKL510 and S. pombe rad2 genes is structurally distinct from the ERCC5 locus but retains vestigial A and B domain similarities. Our analyses suggest that ERCC5 is a nuclear-localized protein with one or more highly conserved helix-loop-helix segments within domains A and B.

Amino Acid Sequence↗
PubMed1993

Measurement of gastric emptying in infants with pyloric stenosis using applied potential tomography.

Gastric emptying in a group of 49 vomiting infants with infantile hypertrophic pyloric stenosis (IHPS) was investigated using applied potential tomography. Fourteen asymptomatic infants were also studied as a control group. A Dioralyte test feed (25 ml/kg/feed) was used for all the studies. The infants with IHPS were investigated before and at two, four, and seven days after an operation; the other infants were investigated once. The results show that the infants with IHPS have no or little gastric emptying before the operation and gradually return to normal emptying by the seventh day after the operation. A significant difference in gastric emptying was noted between the control infants and the infants with IHPS before and at two and four days after the operation. The applied potential tomography method is suitable for studying gastric emptying in infants, with no morbidity nor complications. It also allows multiple studies to be performed without upset or discomfort.

Electric Impedance↗
PubMed1992

Site-specific mutagenesis of the 35-kilodalton protein gene encoded by Autographa californica nuclear polyhedrosis virus: cell line-specific effects on virus replication.

The gene encoding the 35-kDa protein (35k gene) located within the EcoRI-S genome fragment of Autographa californica nuclear polyhedrosis virus (AcMNPV) is transcribed early in infection. To examine its function(s) with respect to virus multiplication, we introduced specific mutations of this early gene into the AcMNPV genome. In Spodoptera frugiperda (SF21) culture, deletion of the 35K gene reduced yields of extracellular, budded virus from 200- to 15,000-fold, depending on input multiplicity. Mutant replication was characterized by dramatically diminished levels of late and very late (occlusion-specific) virus gene expression and premature cell lysis. In contrast, 35K gene inactivation had no effect on virus growth in cultured Trichoplusia ni (TN368) cells. Insertion of the 35K gene and its promoter at an alternate site (polyhedrin locus) restored virus replication to wild-type levels in SF21 culture. Subsequent insertion of 4 bp after codon 81 generated a frameshift mutant that exhibited a virus phenotype indistinguishable from that of 35K deletion mutants and demonstrated that the 35K gene product (p35) was required for wild-type replication in SF21 cells. Mutagenesis also indicated that the C terminus of p35, including the last 12 residues, was required for function. In complementation assays, wild-type virus bearing a functional 35K gene allele stimulated all aspects of 35K null mutant replication and suppressed early cell lysis. These findings indicated that p35 is a trans-dominant factor that facilitates AcMNPV growth in a cell line-specific manner.

Amino Acid Sequence↗
PubMed1992

Ovarian cysts and tumours in childhood.

The clinical features of 39 children with ovarian cysts and tumours are presented. Over two-thirds presented as an emergency with abdominal pain. Thirty-four patients had benign ovarian disease. Only two of the five malignant tumours were of primary ovarian origin. Ultrasonography and computed tomographic scanning can be of valuable assistance in diagnosis and planning surgery. The diagnosis of ovarian cysts and tumours should be considered among the less common causes of acute abdominal pain in children.

Adolescent↗
PubMed1991

Identification of upstream promoter elements mediating early transcription from the 35,000-molecular-weight protein gene of Autographa californica nuclear polyhedrosis virus.

Site-directed mutagenesis was used to examine the organization of cis-acting regulatory elements that comprise the promoter of the early 35,000-molecular-weight protein gene (35K protein gene) encoded by the EcoRI-S region of the baculovirus Autographa californica nuclear polyhedrosis virus. The promoter fragment, extending from positions -226 to +12 relative to the early RNA start site (position +1), was fused to the reporter gene encoding chloramphenicol acetyltransferase (CAT) and then inserted into the genome of recombinant viruses (3.96 map units) in order to ascertain the role of regulatory elements in the context of a normal infection. A combination of deletions and linker insertions revealed that early transcription was mediated by a basal (minimum) promoter, consisting of the TATA element (positions -30 to -25), that was in turn responsive to an upstream activating region located between -90 and -30. The TATA element exerted the single greatest influence on the level of early promoter activity and contained all information necessary to direct transcription from a site located 30 nucleotides downstream. The upstream activating region provided a 10- to 15-fold stimulation of transcription from the early +1 start site that was mediated by distinct DNA elements. These regulatory elements included two GC motifs (centered at positions -81 and -54, respectively), composed of alternating G and C residues, and a CGT motif (position -40) that contained the core sequence A(A/T)CGT(G/T). Each motif was required for full promoter activity during the early phase of infection. This organization that employs diverse cis-acting stimulatory elements is typical of promoters responsive to RNA polymerase II and may facilitate increased expression of A. californica nuclear polyhedrosis virus genes early in infection when the level of viral DNA for transcription is critically low.

Animals↗
PubMed1990

Orchidopexy: the younger the better?

The optimum age for orchidopexy in childhood remains controversial. Many believe that it should be performed before the child's second birthday, when irreversible changes occur in testicular morphology. Others have shown an increase in the risk of damage to the spermatic cord structures in early operation, resulting in gonadal atrophy. We reviewed 200 patients: 100 had had orchidopexy before and 100 after their second birthday. From the case records and from long-term review, we found that 5% of the testes in each group became atrophic. Some testes, which were 'normal' at the 6-month review, had subsequently failed to increase in size, whereas some which were initially diagnosed as 'atrophic' had grown, by long-term follow-up to a similar, normal size compared with the contralateral organ. In the older group, we also found that 19 testes that had previously been diagnosed as having descended normally had ascended subsequently.

Adolescent↗
PubMed1989

Cervical thymic cysts.

Four cases of cervical thymic cyst are described. Clinical and microscopic appearances are reviewed, with reference to its distinction from branchial cyst. The use of monoclonal antibodies to cytokeratin as a histologic aid to diagnosis is discussed.

Child↗