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Biomedical subjects

S Aslam

Publications and source records attributed to S Aslam.

At least 19 recordsLinked to original sources
PubMed2001

Common iliac artery stenosis presenting as renal allograft dysfunction in two diabetic recipients.

BACKGROUND: Suprarenal common iliac artery stenosis is an uncommon but reversible cause of allograft dysfunction in renal transplant recipients. METHOD: We describe two diabetic renal transplant recipients with worsening hypertension, edema, and azotemia. Magnetic resonance angiography (MRA) demonstrated tight stenoses in the common iliac artery proximal to the allograft anastomosis site with patent renal transplant artery in both cases. These findings were later confirmed with carbon dioxide angiography. RESULTS: No acute rejection was noted on renal biopsy in either case. Placement of percutaneous iliac artery Wallstents resulted in decrease of serum creatinine from 6.5 to 2.0 mg/dl and 1.7 to 1.0 mg/dl within 2 and 4 weeks, respectively. CONCLUSION: Common iliac artery stenosis should be suspected in renal transplant recipients presenting with worsening hypertension, edema and azotemia. MRA for screening followed by carbon dioxide angiography and placement of intravascular stents for focal vascular obstructive lesions reverses allograft dysfunction.

Adult↗
PubMed2000

Aortic valve endocarditis due to Staphylococcus capitis.

Native valve endocarditis due to Staphylococcus capitis is uncommon and is usually managed conservatively with good outcome. Of the nine previously reported cases there has been only one mortality. We report a case of native aortic valve endocarditis due to S capitis in an elderly diabetic that had a fatal outcome despite appropriate therapy with antibiotics. A review the literature is also presented.

Adult↗
PubMed2000

Evolutionary conservation of redundancy between a diverged pair of forkhead transcription factor homologues.

The Caenorhabditis elegans gene pes-1 encodes a transcription factor of the forkhead family and is expressed in specific cells of the early embryo. Despite these observations suggesting pes-1 to have an important regulatory role in embryogenesis, inactivation of pes-1 caused no apparent phenotype. This lack of phenotype is a consequence of genetic redundancy. Whereas a weak, transitory effect was observed upon disruption of just T14G12.4 (renamed fkh-2) gene function, simultaneous disruption of the activity of both fkh-2 and pes-1 resulted in a penetrant lethal phenotype. Sequence comparison suggests these two forkhead genes are not closely related and the functional association of fkh-2 and pes-1 was only explored because of the similarity of their expression patterns. Conservation of the fkh-2/pes-1 genetic redundancy between C. elegans and the related species C. briggsae was demonstrated. Interestingly the redundancy in C. briggsae is not as complete as in C. elegans and this could be explained by alterations of pes-1 specific to the C. briggsae ancestry. With overlapping function retained on an evolutionary time-scale, genetic redundancy may be extensive and expression pattern data could, as here, have a crucial role in characterization of developmental processes.

Amino Acid Sequence↗
PubMed1999

Prenatal diagnosis in factor XIII-A deficiency.

Congenital factor XIII deficiency is a severe bleeding disorder that is inherited as an autosomal recessive trait. The condition is commonly due to absence of the factor XIII-A subunit protein in the plasma. The case of a baby is reported who showed typical clinical features of factor XIII-A deficiency, including recurrent bleeding from the umbilical stump and a life threatening haemorrhage after circumcision. Family studies were performed and molecular analysis, using a Short Tandem Repeat (STR) marker closely linked to the A subunit gene, allowed antenatal exclusion diagnosis to be undertaken in a subsequent pregnancy. The case highlights the importance of seeking a family history of bleeding disorders before surgery in the neonatal period, particularly if the parents are consanguineous.

Consanguinity↗
PubMed1999

Clinical scoring system: a valuable tool for decision making in cases of acute appendicitis.

OBJECTIVE: Decision making in cases of acute appendicitis poses a clinical challenge specially in developing countries where advanced radiological investigations do not appear cost effective and so clinical parameters remain the mainstay of diagnosis. The aim of our study was to devise a scoring system from our local database and test its accuracy in the preoperative diagnosis of acute appendicitis. METHODS: Clinical data from 401 patients having undergone appendectomy were collected to identify predictive factors that distinguished those with appendicitis from those who had a negative appendectomy. Ten such factors were identified and using Bayesian probability a weight was assigned to each and the results summated to get an overall score. A cut-off point was identified to separate patients for surgery and those for observation. The scoring system was then retrospectively applied to a second population of 99 patients in order to compare suggested actions (derived from the scoring system) to those actually taken by surgeons. The sensitivity, specificity and accuracy for the level of decision was then calculated. RESULTS: Of the 99 patients, the method suggested immediate surgery for 65 patients, 63 of whom had acute appendicitis (3.1% diagnostic error rate). Of the 33 patients in whom the score suggested active observation, 18 had appendicitis. The accuracy of our scoring system was 82%. The method had a sensitivity of 78%, specificity 89% and a positive predictive value of 97%. The negative appendectomy rate determined by our study was 7% and the perforation rate 13%. CONCLUSION: Scoring system developed from a local database can work effectively in routine practice as an adjunct to surgical decision making in questionable cases of appendicitis.

Acute Disease↗
PubMed1998

A novel insertion mutation (1286insC) in exon 9 of the factor XIII-A subunit gene.

Molecular studies have been performed on a Greek family with factor XIII-A subunit deficiency. The 15 exons of the A subunit gene were amplified by polymerase chain reaction and analysed by direct nucleotide sequencing. A homozygous single base insertion (1286insC) in exon 9 of the gene was identified in three affected family members. The insertion results in a frameshift and a premature stop signal a short distance downstream at codon 403. Any A subunit protein expressed is likely to be unstable and lack part of the catalytic core domain together with both beta barrel domains towards the C-terminal of the molecule. This study contributes to our knowledge of the mutational spectrum in patients with factor XIII-A deficiency.

DNA Transposable Elements↗
PubMed1997

Fates of the earliest generated cells in the developing murine neocortex.

In mammalian species studied to date, the first-born neocortical cells normally form two layers, one above and one below the cortical plate, called the marginal zone (future layer 1) and the subplate. In primates and carnivores, many of these first-born cells die early in postnatal life. Whether this also occurs in rodents is highly controversial. In this study, we injected pregnant mice with bromodeoxyuridine on embryonic days (E) 11-14 to label the earliest generated neocortical cells, and examined their fates between birth and postnatal day 21. At birth, most cells born on embryonic day 11 were below the cortical plate, and a smaller proportion were above it. Very few of these cells remained by postnatal day 3 and there were none at any depth in the neocortex at older ages. At birth, the largest proportion of cells born on embryonic days 12 and 13 were in the subplate and smaller proportions were in the cortical plate and marginal zone. At older ages, almost all of these cells had disappeared from the marginal zone and from below the cortical plate, although some were retained in the cortical plate. The density of the remaining E12- and E13-born cells decreased more than could be explained by neocortical expansion alone. As a control, we studied cells born on embryonic day 14. These cells were restricted to the cortical plate at birth. By postnatal day 21, their density had decreased by an amount that could be explained by neocortical expansion alone. We conclude that, as in other species, many of the earliest generated cells of the murine neocortex die.

Age Factors↗
PubMed1997

Bipedicle flaps: simple solutions for difficult problems in the extremities.

Bipedicle flaps have been used to provide good quality soft tissue cover for defects in many anatomical sites. The indications for the use of this flap have not been well defined and with the advent of more complex modes of tissue transfer this simple technique is often overlooked. We have found it to be a safe and expedient method of providing cover for difficult defects on the extremities. We present a series of 9 flaps raised on 7 patients over a 12-month period and discuss the indications and refinements in flap design.

Adult↗
PubMed1997

Temperature profiles during resuscitation predict survival following burns complicated by smoke inhalation injury.

Temperature and resuscitation profiles of 15 non-survivors were compared with matched survivors of major burns. All patients were intubated and ventilated for smoke inhalation injury, survived more than 3 days postburn and had a cutaneous burn greater than 15 per cent of the body surface area (mean 32.3 +/- 11.0 per cent SD). Cases were matched for similar ages (within 10 years) and total body surface area burn (within 10 per cent). The rate of core temperature rise following admission to the burn unit was significantly greater in survivors (mean 0.46 +/0 0.18 degree C/h) compared with matched non-survivors (mean 0.30 +/- 0.15 degrees C/h; p < 0.01). Core temperature increased at a rate of 0.27 degrees C/h or greater in all survivors, whereas 7 non-survivors raised their core temperature at a rate less than this. The rate of skin temperature rise was also significantly greater in the survivors (mean 1.35 +/- 0.91 degrees C/h) compared with matched non-survivors (mean 0.63 +/- 0.43 degrees C/h, p < 0.01). In 13/15 survivors, the skin temperature increased at a rate of 0.6 degree C/h or greater, whereas in 8/15 non-survivors skin temperature increased at a rate less than this. There was a negative relationship between initial core temperature and delay from time of burn to admission to the burns unit in non-survivors (correlation coefficient = -0.92; p < 0.01), whereas there was no effect of delay in the survivors. These findings suggest that patients with a high mortality probability can be detected early in their clinical course by means of temperature profiles.

Adult↗
PubMed1997

Structural analysis of a missense mutation (Val414Phe) in the catalytic core domain of the factor XIII(A) subunit.

Molecular analysis has been performed on a Malaysian patient with a severe bleeding disorder due to factor XIII(A) subunit deficiency. Total mRNA was isolated from the patient's leucocytes and four overlapping segments corresponding to the entire coding region of the A subunit cDNA were amplified by RT-PCR. The cDNA segments amplified efficiently and were of expected size. Direct sequencing of the complete reading frame revealed a single homozygous base change (nt 1327G-T) in exon 10 corresponding to a missense mutation, Val414Phe, in the catalytic core domain of the A subunit monomer. The mutation eliminates a BsaJ1 restriction site and family screening showed that both parents were heterozygous for the defect. The base substitution was absent in 55 normal individuals. Val414 is a highly conserved residue in the calcium-dependent transglutaminase enzyme family. Computer modelling based on 3D crystallographic data predicts that the bulky aromatic side chain of the substituted phenylalanine residue distorts protein folding and destabilizes the molecule. In addition, conformation changes in the adjacent catalytic and calcium binding regions of the A subunit are likely to impair the enzymatic activity of any protein synthesized.

Adult↗
PubMed1997

Rapid diagnosis of asymptomatic hereditary haemochromatosis by detection of the Cys282Tyr mutation in the HLA-H gene.

Hereditary haemochromatosis is an autosomal recessive disorder characterised by life-long excessive accumulation of iron. A candidate gene for hereditary haemochromatosis has recently been reported (HLA-H) and a specific missense mutation (Cys282Tyr) has been identified in 85% of patients with the disorder. We describe the rapid detection of this mutation using the polymerase chain reaction and restriction endonuclease digestion. The usefulness of this test for early diagnosis of hereditary haemochromatosis in asymptomatic family members is highlighted.

Cysteine↗
PubMed1996

Factor XIII(A) subunit deficiency due to a homozygous 13-base pair deletion in exon 3 of the A subunit gene.

We investigated the molecular basis of factor XIII(A) subunit deficiency in a Greek family. Each of the 15 exons of the A subunit gene were individually amplified by polymerase chain reaction, using previously reported oligoprimers. The proband with severe deficiency was found to have a homozygous 13-base pair deletion in the 3' half of exon 3. The deleted sequence, extending from codons 82-86, results in a frameshift and generates a downstream termination codon in exon 4. Single strand conformation polymorphism (SSCP) analysis detected no additional mutations in the coding or consensus splice sequences of the A subunit gene. Both parents of the proband were heterozygous for the defect. Only one previous microdeletion (AG dinucleotide) has been reported in the A subunit gene, and was located at the intron B-exon 3 boundary. Further studies are necessary to determine whether this region of the gene is a "hot spot" for microdeletion mutations.

Amino Acid Sequence↗
PubMed1995

Factor XIIIA Calgary: a candidate missense mutation (Leu667Pro) in the beta barrel 2 domain of the factor XIIIA subunit.

Molecular analysis performed on a Canadian family with congenital factor XIII deficiency revealed a homozygous missense mutation (Leu667Pro) in exon 14 of the A subunit gene in three affected siblings. The mutation results from a T-to-C transition at nucleotide position 2087 and generates a new Msp1 restriction site. Digestion of an amplified fragment containing exon 14 with this restriction enzyme enabled the heterozygous allele to be identified in both parents (who were third cousins) and three other family members. SSCP analysis detected no additional mutations in the coding or consensus splice sequences of the A subunit gene. The mutant nucleotide substitution was absent in 60 normal alleles and 10 unrelated patients with XIIIA deficiency. Leu667 is located in the carboxyl terminal beta barrel 2 domain of the A subunit molecule. Computer modelling based on 3D crystallographic data predicts that the mutant protein has aberrant folding and is likely to be rapidly degraded following translation.

Factor VIIIa↗