Similarities simplify.
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Anesthesia Department, Hospital↗
Biomedical subjects
O A Ahmed
Publications and source records attributed to O A Ahmed.
NMR signal enhancement via a new time-frequency transform.
In this paper, a reliable method to reduce the noise from nuclear magnetic resonance (NMR) signals using a recently developed linear critically sampled time-frequency transform is proposed. In addition to its low computational requirements, this transform has many theoretical advantages that make it a good candidate for NMR signal enhancement. NMR signals in the transform domain are concentrated in a few coefficients while the noise is well distributed. Performing a thresholding technique in the transform domain, therefore, significantly enhances the signal. A comparison with other signal enhancement techniques shows that this technique has a superior performance, thus confirming the theoretical expectations.
Algorithms↗
The 4q-Syndrome.
The 4q-Syndrome: Here we report four cases of interstitial and terminal deletions of the long arm of chromosome 4. Case 1 is a 16 month old boy with del(4)(q12q21) who has soft dysmorphic features, tetralogy of Fallot, and severe developmental delay. Case 2 is a male infant with the same deletion and congenital cardiomyopathy. He suffered severe birth asphyxia and died at the age of 6 months. His father was found to have a complex chromosome 4 rearrangement. Case 3 is a female infant with del(4)(q33) who died of aspiration pneumonia. She was mildly dysmorphic and presented with heart failure and hypercalcaemia. Case 4 is a 8 month old girl who has del(4)(q33) and Pierre-Robin sequence. So far about 70 patients with microscopically visible deletions of chromosome 4q have been described. Although they vary in their phenotypes, they have several features in common. We suggest to use the term 4q-syndrome for all macrodeletions of the long arm of chromosome 4.
Abnormalities, Multiple↗
Non-syndromic mental retardation segregating with an apparently balanced t(1;17) reciprocal translocation through three generations.
We describe a family in which non-syndromic mental retardation (MR) and an apparently balanced reciprocal translocation, t(1;17)(p36. 3;p11.2) segregates in eight individuals over three generations. Four children showed psychomotor developmental delay, reduced muscle tone, poor coordination, and learning difficulties. The affected adults had a varying range of behavioral problems and difficulties in social adjustment but no abnormal neurological signs. Most of them were functioning at the borderline learning difficulty level in intellectual abilities with additional specific difficulties in reading in two individuals. The Smith-Magenis and 1p36.3 deletion syndromes were excluded. We propose that this reciprocal translocation has disrupted an autosomal gene with an important function in cognitive development, and this family represents a unique resource for the molecular genetic study on non-syndromic MR.
Adolescent↗
Comparison of nipple and areolar sensation after breast reduction by free nipple graft and inferior pedicle techniques.
Breast reduction with free nipple-areolar transplantation has traditionally been used for patients with gigantomastia. It is a widely held belief that there is little or no recovery of sensation in the nipple-areolar complex after this procedure. We set up a retrospective study to compare nipple-areolar sensation after free nipple grafting with that after breast reduction by the more commonly performed inferior pedicle technique. We reviewed 38 patients (17 free nipple grafts and 21 inferior pedicles) at least 1 year after breast reduction and measured the nipple and areolar pressure sensibility in each breast with Semmes-Weinstein monofilaments. We found some degree of recovery of sensation in all patients, with areolar sensation being similar in the two groups but nipple sensation being superior in the inferior pedicle group. In addition, we assessed the erectile function of the nipples in each group.
Adult↗
Mycobacterium tuberculosis presenting as sternal osteomyelitis.
A 54-year-old female presented with a presternal abscess and developed axillary lymphadenopathy. Imaging confirmed the presence of sternal osteomyelitis. The osteomyelitis was cured by resection and muscle flap reconstruction. Although tuberculosis was suspected, the organism was only cultured after the fourth surgical procedure. Surgeons should be aware that negative microbiology does not exclude a diagnosis of Mycobacterium tuberculosis.
Diagnosis, Differential↗
Prevention of Frey's syndrome and volume deficit after parotidectomy using the superficial temporal artery fascial flap.
Frey's syndrome (gustatory sweating) is thought to be caused by aberrant regeneration to the sweat glands of the face. We present a double-layered fascial flap based on the superficial temporal artery which can be used to cover the parotid bed at the time of parotidectomy and consists of both the temporoparietal fascia and the fascia over the temporalis muscle. We used this superficial temporal artery fascial flap (STAFF) in 24 of 47 patients reviewed after parotid surgery and found a significantly lower incidence of gustatory sweating and a far less noticeable post-parotidectomy volume deficit or 'hollow'.
Adolescent↗
Congenital rhabdomyosarcoma.
A congenital rhabdomyosarcoma presented as a partially necrotic mass on the left forearm on delivery at term. Ulceration and persistent bleeding were managed by primary curettage followed by local resection including partial excision of the muscles of the extensor compartment of the forearm. The defect was resurfaced with a split skin graft. The surgery was followed by chemotherapy according to the IVA regime. There was no recurrence at 2 years of age and the limb was fully functional. The presentation and management of rhabdomyosarcoma are discussed.
Female↗
Antibody responses and reactions to the whole cell pertussis component of a combined diphtheria/tetanus/pertussis vaccine given at school entry.
To measure the clinical effect of adding a whole cell pertussis component to diphtheria/tetanus vaccine (DT) given as a pre-school booster, 190 children aged 4-5 years were randomised by a double-blind method to receive either diphtheria/tetanus/pertussis (DTP) or DT vaccine in a 1:1 ratio at selected clinics in England. The geometric mean antibody titres to each of the three pertussis antigens were at least sixfold higher in the DTP than the DT vaccine group and equalled or exceeded those in infants immediately after primary immunisation with DTP vaccine. There were no significant differences between DTP and DT vaccinated children in their diphtheria and tetanus antitoxin levels. The frequency of large local reactions and systemic symptoms such as crying and a disturbed night was 2-3-fold higher in the DTP vaccinees than in the DT vaccinees. Medication was given to 44% of DTP and 23% of DT vaccinees (p = 0.006). Although the change to whole cell DTP vaccine at school entry would result in good pertussis antibody titres, the 2-3-fold increase in reactogenicity that would be caused may be unacceptable at a time when whooping cough is not circulating widely. Evaluation of acellular DTP vaccines given as a pre-school booster in children vaccinated under the accelerated schedule is planned.
Antibody Formation↗
Caring for patients with asthma. Parents must know when to intervene.
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Asthma↗
The prevalence of ABO blood group antigens and antibodies in Lagos State, Nigeria.
A total of 1239 normal donors from the Lagos University Teaching Hospital (LUTH) and 111 staff of the National Institute for Medical Research (NIMR) Yaba were screened for ABO antibodies. Of the number from LUTH, 220 (17.8%) were found to be in group A, 282 (22.8%) in group B, 85 (6.9%) in group AB and 652 (52.6%) in group O. The number from NIMR consisted of 20 (18.0%) in group A, 25 (22.5%) in group B 8(7.2%) in group AB and 58 (52.3%) in group O. The mean tile avidity time of sera from 789 (62.66%) potent LUTH donors was less than 35 seconds. Only 97 (6.91%) of this reacted within 10 seconds. On the other hand, only 11(9.9%) of the NIMR sera reacted within 35 seconds and none reacted within 10 seconds. Group O individuals from LUTH and NIMR did not always have anti-A and anti-B components of their sera with equal avidity or potency. It was also observed that high avidity of antibody did not necessarily correspond with high potency. The commonest titre for group B (anti-A) sera was 256 and that for group A (anti-B) was 512. In general, anti-B titres tended to be consistently higher than anti-A. There was a bimodal peak at titres 32 and 256 in group B (anti-A) sera. This repeated itself in the anti-A component of group O sera (i.e., anti-A+B), but here the peaks occurred at 32 and 128.(ABSTRACT TRUNCATED AT 250 WORDS)
ABO Blood-Group System↗
High-performance liquid chromatographic analysis of MTX, 7-OH-MTX and MTX derivatives: application to intracellular metabolism in tumor cells (HT 29).
In order to study the intracellular metabolism of Methotrexate (MTX) and the cytotoxicity of the antifolates, a specific paired-ion HPLC method has been developed which permits the simultaneous determination of DAMPA, MTX, 7-OH-MTX, MTX-G1, MTX-G2 and MTX-G3. Cells were incubated with 3H-MTX. The MTX metabolites were extracted, purified on SEP-PAK cartridges and further analysed by high-performance liquid chromatography (HPLC). The stationary phase was constituted by a C18 muBondapak and the mobile phase by 5 mM phosphate buffer (pH 7.4) containing 2.5 mM tetrabutylammonium nitrate. The elution was performed with a linear methanol gradient (20--30%). HPLC fractions were collected and radioactivity evaluated by beta counting (retention times: DAMPA = 12.93 min; MTX = 18.29 min; 7-OH-MTX = 21.13 min; MTX-G1 = 22.69 min; MTX-G2 = 26.81 min; MTX-G3 = 30.61 min). This analytical procedure was applied to separate and characterize multiple forms of MTX polyglutamate derivatives in HT 29, a human adenocarcinoma cell line varying the incubation time (4--18 h) and MTX concentration (0.6--10.6 micrometer). The incorporation process seems to be characteristic of a cell line resistant to MTX. The incorporation were very low and after a 4-h exposure time only 5% of the MTX was converted to polyglutamates. Between 1.6 and 10.6 microM MTX, no difference was observed in the polyglutamization. The defect in the incorporation of the drug and in the metabolization process in vitro could partially explain the failure of the MTX treatment in colorectal cancer.
Adenocarcinoma↗
Parallel activation of cyclic AMP phosphodiesterase and cyclic AMP-dependent protein kinase in two human gut adenocarcinoma cells (HT 29 and HRT 18) in culture, by vasoactive intestinal peptide (VIP) and other effectors activating the cyclic AMP system.
Vasoactive intestinal peptide (VIP), secretin, catecholamines and prostaglandin E1 (PGE1) in the presence of a cyclic nucleotide phosphodiesterase inhibitor stimulate the accumulation of cyclic AMP in two colorectal carcinoma cell lines (HT 29 and HRT 18) with subsequent activation of the cyclic AMP-dependent protein kinases. In HT 29 cells incubated without phosphodiesterase inhibitor, 10(-9) M VIP promotes a rapid and specific activation of the lower Km cyclic AMP phosphodiesterase (1.7-fold); at 25 degrees C the effect is maintained for more than 15 min, while at 37 degrees C the activity returns to basal value within 15 min. As shown by dose-response studies, VIP is by far the most effective inducer (Ka equals 4 x 10(-10) M) of the cyclic AMP phosphodiesterase activity; partial activation of the enzyme is obtained by 3 x 10(-7) M secretin, 10(-5) M isoproterenol and 10(-5) M PGE1; PGE2 and epinephrine are without effect. In HRT 18 cells VIP is less active (Ka equals 2 x 10(-9) M) whereas 10(-6) M PGE1, 10(-6) M PGE2 and 10(-5) M epinephrine are potent inducers of th phosphodiesterase activity. The positive cell response to dibutyryl-cyclic AMP further indicates that cyclic AMP is a mediator in the phosphodiesterase activation process. The incubation kinetics and dose response effects of the various agonists on the cyclic AMP-dependent protein kinase activity determined for both cell types in the same conditions show a striking similarity to those of phosphodiesterase. Thus coordinate regulation of both enzymes by cyclic AMP was observed in all incubation conditions.
3',5'-Cyclic-AMP Phosphodiesterases↗
Hamster challenge potency assay for evaluation of Mycoplasma pneumoniae vaccines.
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Animals↗
Activation of cyclic AMP-dependent protein kinases in human gut adenocarcinoma (HT 29) cells in culture.
Vasoactive intestinal peptide, secretin, catecholamines and prostaglandin E1 stimulate the accumulation of cyclic AMP in HT 29 cells (see Laburthe, M. et al. (1978) Proc. Natl. Acad. Sci. U.S. 75, 2772-2775). In the present work maximal activation of protein kinases has been obtained at similar or even lower concentrations of the effectors. Maximal stimulation also requires a phosphodiesterase inhibitor. Type I and type II cyclic AMP-dependent protein kinases from basal and stimulated cells have been characterized by DEAE-Sepharose chromatography. Further identidication of the kinase has been carried out by gel electrophoresis and assay of the enzymes in the gel slabs. Comparison of the radioautography patterns of high speed supernatant lysate from basal and stimulated cells shows: First, that one type I and two type II cyclic AMP-dependent protein kinases plus one or two major and two minor cyclic AMP-independent protein kinases are present in HT 29 cells. Second, that all three holoenzymes are fully dissociated upon maximal stimulation, while the activity of the independent kinases appears unchanged.
Adenocarcinoma↗
Serum ferritin and other haematological measurements in apparently healthy children with malaria parasitaemia in Lagos, Nigeria.
One hundred apparently normal nursery and primary school children aged between 2 to 12 years from private schools, in Lagos Nigeria were studied. From this study the mean ferritin levels for children aged 2-5 years, and 6-12 years were 112 +/- 48 micrograms/l, and 119 +/- 38 micrograms/l respectively. Mean haematocrit values were 37.6 +/- 2.2%, and 37.5 +/- 2.6%, while mean haemoglobin levels were 126 +/- 9 g/l 127 +/- 7.9 g/l (2-5 years and 6-12 years respectively). The mean values for MCV, MCH, MCHC were 92 +/- 8.6 fl, 27.6 +/- 3.0 pg, 338.0 +/- 15.0 g/l and 93.5 +/- 9.0 fl, 28.7 +/- 2.5 pg, 332.0 +/- 17.0 g/l (2-5 years and 6-12 years respectively). All haematological parameters measured were similar in both malaria parasitaemia positive and negative subjects, except ferritin level which was significantly higher in subjects with malaria parasitaemia (p < 0.05). There was positive correlation between ferritin concentration and malaria density (r = 0.85, p < 0.05). From the above findings, it would be concluded that, ferritin estimation without examination for malaria parasitaemia in a malarious region like Nigeria is not reliable. It is also concluded that with the high mean ferritin level obtained in this study for normal children on balanced diet, routine iron supplementation may not be necessary for this group of children in Nigeria.
Child↗
Tissue irritation induced in turkeys by fowl cholera bacterins.
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Adjuvants, Immunologic↗