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Biomedical subjects

S Mohammed

Publications and source records attributed to S Mohammed.

At least 19 recordsLinked to original sources
PubMed2006

In vivo measurements of macular and nerve fibre layer thickness in retinal arterial occlusion.

AIM: To investigate the structure-function relationship in patients with retinal arterial occlusion by measuring the macular and the peripapillary retinal nerve fibre layer (RNFL) thickness and the visual sensitivity. METHODS: This is an observational case series with three patients with central retinal arterial occlusion (CRAO) and two patients with branch retinal arterial occlusion (BRAO). The macular/peripapillary RNFL thickness and the visual field were measured with Stratus optical coherence tomography (OCT) and Humphrey visual field analyzer, respectively, at least 1 year after the diagnosis of CRAO or BRAO. RESULTS: The macular thickness, in particular the inner retinal layer, and the peripapillary RNFL thickness were reduced in patients with retinal arterial occlusion. The decrease in the macular and the peripapillary RNFL thickness corresponded to the sites of retinal arterial occlusion with diffuse and segmental thinning found in CRAO and BRAO, respectively. Visual field defects were found in the corresponding locations of macular and RNFL thinning, and closely correlated with the degree of the structural damage. CONCLUSIONS: Structural damages in terms of reduction in the macular and peripapillary RNFL thickness were evident in patients with retinal arterial occlusion. A close structure-function correlation was found and a worse functional outcome is associated with a more extensive thinning of the macula and RNFL. OCT measurements of the macular/peripapillary RNFL thickness provide useful indicators to reflect the severity of the disease in retinal arterial occlusion and serve as a new paradigm to study and monitor the disease longitudinally.

Adult↗
PubMed2006

Phosphopeptide quantitation using amine-reactive isobaric tagging reagents and tandem mass spectrometry: application to proteins isolated by gel electrophoresis.

Polyacrylamide gel electrophoresis is widely used for protein separation and it is frequently the final step in protein purification in biochemistry and proteomics. Using a commercially available amine-reactive isobaric tagging reagent (iTRAQ) and mass spectrometry we obtained reproducible, quantitative data from peptides derived by tryptic in-gel digestion of proteins and phosphoproteins. The protocol combines optimized reaction conditions, miniaturized peptide handling techniques and tandem mass spectrometry to quantify low- to sub-picomole amounts of (phospho)proteins that were isolated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Immobilized metal affinity chromatography (FeIII-IMAC) was efficient for removal of excess reagents and for enrichment of derivatized phosphopeptides prior to matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis. Phosphopeptide abundance was determined by liquid chromatography/tandem mass (LC/MS/MS) using either MALDI time-of-flight/time-of-flight (TOF/TOF) MS/MS or electrospray ionization quadrupole time-of-flight (ESI-QTOF) MS/MS instruments. Chemically labeled isobaric phosphopeptides, differing only by the position of the phosphate group, were distinguished and characterized by LC/MS/MS based on their LC elution profile and distinct MS/MS spectra. We expect this quantitative mass spectrometry method to be suitable for systematic, comparative analysis of molecular variants of proteins isolated by gel electrophoresis.

Amines↗
PubMed2006

Prevalence of uterine synechiae among infertile females in a Nigerian teaching hospital.

The purpose of this study was to assess the prevalence of uterine synechiae among infertile females in our setting. This was a retrospective review of 250 patients who underwent hysterosalpingography using 76% Urografin as part of infertility work-ups at the University of Teaching Hospital between January 1996 and December 2000. Those with uterine synechiae were closely evaluated. The incidence of uterine synechiae was 34 (13.6%). The peak incidence was in the age group 30 - 34 years. Uterine synechiae were less common at the extremes of reproductive years. The prevalence of uterine synechiae is high in our environment and will tend to increase due to promiscuity and criminal abortions by unqualified personnel.

Adolescent↗
PubMed2004

Penetrating keratoplasty in adults with congenital glaucomas.

PURPOSE: To report the problems and outcomes of penetrating keratoplasty (PKP) in patients with corneal oedema due to congenital glaucoma. METHOD: Case note review of nine such consecutive patients treated with PKP. A Kaplan - Meir survival curve was plotted for the series. RESULTS: Nine patients, ranging in age from 27 to 71 years at the time of their surgery were followed up for a mean of 28 months. All had undergone previous surgery for glaucoma. Preoperatively all patients had controlled intraocular pressures, and four were on ocular hypotensives. Two patients developed corneal graft failure at 15 and 41 months postoperative. Raised pressure was the cause in both. Final visual acuity improved in five patients, was the same in three, and deteriorated in only one. Complications included raised intraocular pressure, cataract, retinal detachment, and endophthalmitis secondary to an infected Molteno implant. CONCLUSION: Despite multiple impediments to good postoperative vision including previous surgery and pre-existing glaucomatous damage, a successful outcome was achieved by careful patient selection, and an awareness of, and meticulous attention to postoperative complications.

Adult↗
PubMed2004

A randomised, controlled trial of once daily and multi-dose daily gentamicin in young Kenyan infants.

AIMS: To test the suitability of a simple once daily (OD) gentamicin regimen for use in young infants where routine therapeutic drug monitoring is not possible. METHODS: In an open, randomised, controlled trial, infants with suspected severe sepsis admitted to a Kenyan, rural district hospital received a novel, OD gentamicin regimen or routine multi-dose (MD) regimens. RESULTS: A total of 297 infants (over 40% < or =7 days) were randomised per protocol; 292 contributed at least some data for analysis of pharmacological endpoints. One hour after the first dose, 5% (7/136) and 28% (35/123) of infants in OD and MD arms respectively had plasma gentamicin concentrations <4 microg/ml (a surrogate of treatment inadequacy). Geometric mean gentamicin concentrations at this time were 9.0 microg/ml (95% CI 8.3 to 9.9) and 4.7 microg/ml (95% CI 4.2 to 5.3) respectively. By the fourth day, pre-dose concentrations > or =2 microg/ml (a surrogate of potential treatment toxicity) were found in 6% (5/89) and 24% (21/86) of infants respectively. Mortality was similar in both groups and clinically insignificant, although potential gentamicin induced renal toxicity was observed in <2% infants. CONCLUSIONS: A "two, four, six, eight" OD gentamicin regime, appropriate for premature infants and those in the first days and weeks of life, seems a suitable, safe prescribing guide in resource poor settings.

Anti-Bacterial Agents↗
PubMed2004

Current practices and medico-legal aspects of pre-operative consent.

BACKGROUND: Written informed consent is a pre requisite for surgical intervention as it provides the forum for the patient to appreciate implications of the procedure and the doctor to explain details and effects of the surgery. OBJECTIVES: To evaluate the practice of obtaining informed consent pre-operatively by surgeons in Benin City and proffer solutions that would enhance its practice. DESIGN: Cross-sectional study involving surgical patients or their relations or gurdian (in cases involving minors and unconscious patients) who were interviewed with structured ended questionnaires. SETTING: Study was carried out at the University of Benin Teaching Hospital, Benin City, between 5th July and 6th September 2002. RESULTS: One hundred and thirty-three respondents; 53(39.2%) males and 80(60.2%) females were interviewed. Documentations regarding consent were noted in 118(88.7%) cases. Of these, 74.6% felt they had enough time to reflect on the consent obtained while 48(36.1%) respondents were meeting the individual who obtained their consent for the first time. The content of information offered patients prior to obtaining consent was found to be significantly related to the levels of education (X2= 31.44; P<0.001). Over a hundred respondents were not informed of risk of procedure. Nonetheless over 50% of respondents felt satisfied with information supplied. CONCLUSION: The quality of consent obtained from the average patient fell below expected standard. There is need for greater awareness amongst administrators of consent on the essence of improving quality of information given and mode of obtaining consent from patients.

Adolescent↗
PubMed2003

Causes and outcome of young infant admissions to a Kenyan district hospital.

AIMS: To provide a comprehensive description of young infant admissions to a first referral level health facility in Kenya. These data, currently lacking, are important given present efforts to standardise their care through the integrated management of childhood illness (IMCI) and for prioritising both health care provision and disease prevention strategies. METHODS: Prospective, 18 month observational study in a Kenyan district hospital of all admissions less than 3 months of age to the paediatric ward. RESULTS: A total of 1080 infants were studied. Mortality was 18% overall, though in those aged 0-7 days it was 34%. Within two months of discharge a further 5% of infants aged <60 days on admission had died. Severe infection and prematurity together accounted for 57% of inpatient deaths in those aged <60 days, while jaundice and tetanus accounted for another 27%. S pneumoniae, group B streptococcus, E coli, and Klebsiella spp. were the most common causes of invasive bacterial disease. Hypoxaemia, hypoglycaemia, and an inability to feed were each present in more than 20% of infants aged 0-7 days. Both hypoxaemia and the inability to feed were associated with inpatient death (OR 3.8 (95% CI 2.5 to 5.8) and 7.4 (95% CI 4.8 to 11.2) respectively). CONCLUSIONS: Young infants contribute substantially to paediatric inpatient mortality at the first referral level, highlighting the need both for basic supportive care facilities and improved disease prevention strategies.

Bacterial Infections↗
PubMed2003

Abnormal blood glucose concentrations on admission to a rural Kenyan district hospital: prevalence and outcome.

AIMS: To determine the prevalence, clinical characteristics, and outcome of hypoglycaemia on admission in children at a rural Kenyan district hospital. METHODS: Observational study of 3742 children (including 280 neonates) in Kilifi District Hospital, Kenya. MAIN OUTCOME MEASURES: hypoglycaemia (blood glucose <2.2 mmol/l) and hyperglycaemia (blood glucose >10.0 mmol/l). RESULTS: Non-neonates: the prevalence of hypoglycaemia on admission was 7.3%. Severe illness, malnutrition, last meal >12 hours ago, and a positive malaria slide were independently associated with hypoglycaemia. Overall, mortality in hypoglycaemic children was 20.2% compared to 3.8% in normoglycaemic children (p < 0.001). The brunt of mortality in hypoglycaemic children was borne by those who were severely ill or malnourished (31.8%) as opposed to those who were neither severely ill nor malnourished (9.0%). Neonates: 23.0% of neonates were hypoglycaemic on admission. Inability to breast feed and weight <2500 g were independently associated with hypoglycaemia. Mortality was 45.2% compared to 19.6% in normoglycaemic neonates (p < 0.001). Hyperglycaemia was present in 2.7% of children and was associated with a higher mortality than normoglycaemia, 14.0% versus 3.8% respectively (p < 0.001). CONCLUSIONS: Hypoglycaemia is common in children admitted to a rural Kenyan district hospital and is associated with an increased mortality. Apart from features of severe illness and poor feeding, clinical signs have a low sensitivity and specificity for hypoglycaemia. Where diagnostic facilities are lacking, presumptive treatment of severely ill children is recommended. For other children, the continuation of feeding (by nasogastric tube if necessary) should be part of standard management.

Age Distribution↗
PubMed2002

Evidence for separate disease phenotypes in intestinal Crohn's disease.

BACKGROUND: This study investigated the hypothesis that separate phenotypes of Crohn's disease exist which display differing patterns of recurrence with a tendency to preservation of phenotype between serial operations. METHODS: Some 483 abdominal operations (278 patients) were identified from a prospectively compiled database. Patterns of recurrence (reoperation) were analysed by Kaplan-Meier plots and log rank tests according to disease phenotype (perforated, stenosed or ulcerated). Serial operations were analysed by agreement of phenotype and microscopic features of disease using kappa statistics and correlation coefficients. RESULTS: There was no significant difference in recurrence according to disease phenotype (median reoperation-free survival time 43.0, 50.2 and 47.9 months for perforated, stenosed and ulcerated types respectively; log rank chi(2) = 3.5, P = 0.18). There was poor agreement in phenotype between serial operations (kappa = 0.22 for first/second operation and kappa= 0.15 for second/third operation) and no significant correlation between pathological features was identified (r between -0.19 and 0.48). CONCLUSION: No evidence was found for the existence of separate disease phenotypes with differing natural histories or underlying pathological characteristics.

Crohn Disease↗
PubMed2001

A novel tandem quadrupole mass spectrometer allowing gaseous collisional activation and surface induced dissociation.

A novel tandem quadrupole mass spectrometer is described that enables gaseous collision-induced dissociation (CID) and surface-induced dissociation (SID) experiments. The instrument consists of a commercially available triple quadrupole mass spectrometer connected to an SID region and an additional, orthogonal quadrupole mass analyser. The performance of the instrument was evaluated using leucine-enkephalin, allowing a comparison between CID and SID, and with previous reports of other SID instruments. The reproducibility of SID data was assessed by replicate determinations of the collision energy required for 50% dissociation of leucine-enkephalin; excellent precision was observed (standard deviation of 0.6 eV) though, unexpectedly, the reproducibility of the equivalent figure for CID was superior. Several peptides were analysed using SID in conjunction with liquid secondary-ion mass spectrometry or electrospray; a comparison of the fragmentation of singly protonated peptide ions and the further dissociation of y-type fragments was consistent with the equivalence of the latter fragments to protonated peptides. Few product ions attributable to high-energy cleavages of amino acid side-chains were observed. The SID properties were investigated of a series of peptides differing only in the derivatization of a cysteine residue; similar decomposition efficiencies were observed for all except the cysteic acid analogue, which demonstrated significantly more facile fragmentation.

Amino Acid Sequence↗
PubMed2000

Detection of submicroscopic subtelomeric chromosome translocations: a new case study.

Two sisters presented with multiple congenital abnormalities and developmental delay; abnormalities elsewhere in their extended family suggested that their father carried a balanced translocation. G-banded chromosome analysis showed apparently normal karyotypes. Fluorescence in situ hybridisation (FISH) with whole chromosome paints revealed no apparent abnormality in the father. However, further FISH studies, using multiple subtelomeric probes, demonstrated a derivative chromosome 16 in one sister. Subsequent studies showed that her sister also had a derivative 16 which had been inherited in an unbalanced form from their father, who carried a balanced reciprocal translocation between chromosomes 1 and 16. This report describes the detection of this submicroscopic translocation and the clinical findings in the two sisters.

Adolescent↗
PubMed2000

Knowledge, attitudes and practices of anabolic steroid usage among gym users in Trinidad.

Self-administered questionnaires were completed by 1062 gym-users in 14 gyms in Trinidad from February 1997 to July 1997 to determine the knowledge, attitudes and practices regarding anabolic steroids (AS). Five hundred and sixty (52.7%) females and 502 (48.3%) males completed the questionnaire. Half of the total sample were individuals in the 20 to 29 year age group. From the 17 questions that tested knowledge about AS, the median number of correct responses was 7 with a mode of 8. Increased muscle mass was correctly identified as one of the effects of AS by 841 respondents (79.2%), while 249 (23.6%) of the total sample thought asthma was treated with AS. Most (872 or 82.1%) felt that their knowledge about AS was inadequate and 700 (66.0%) were of the opinion that AS should be banned from use in competitive sports. Similarly, 733 (70.0%) of the gym-users thought AS should only be available by prescription. Thirty respondents reported having used AS (2.9%, 95% CI 2.0-4.1). The prevalence of AS use was higher among males than females (p < 0.001). Improvement of physical appearance and not competitive advantage in sport was the main reason cited for AS use. Anabolic steroid users knew more about the adverse effects of AS than non-AS users but the therapeutic uses of AS were comparatively less well known. This study demonstrated a general lack of knowledge concerning AS use and that a small but significant proportion of persons using gyms admitted to abusing AS.

Adult↗
PubMed1999

Paediatric nosocomial urinary tract infection at a regional hospital.

From a total of 26,603 admissions to the paediatric wards, 1360 paediatric nosocomial urinary tract infections (PNUTI) were identified during a 5-year retrospective chart review at the SFGH. The ages ranged from 3 days to 13 years, with 46% boys and 54% girls. The highest rates of PNUTI per service per 100 admissions were seen in the nursery (11.28) followed by paediatric surgery (2.89) and paediatric medicine (2.86). Although the greatest number of PNUTI occurred in the nursery, comparison between the years was not statistically significant. About 90% (1218 of 1360) of PNUTI occurred in catheterized patients. No documentation was found specifying the type of catheterization (intermittent or continuous). About 90% (1210 of 1360) of isolates were single organisms with Escherichia coli, Proteus mirabilis, Klebsiella spp. and Group B streptococci accounting for a total of approximately 70% of all pathogens. However, the composition of the most common isolate in each service differed. The most common isolate in the nursery was E. coli, in the paediatric medical and surgical services the most common isolates were Klebsiella spp. and Proteus mirabilis, respectively. Proteus mirabilis was isolated predominantly from boys with structural abnormality of the urethral tract. No PNUTIs were complicated by bacteraemia. The antibiotics with least effectiveness (in increasing order) for UTIs were cephalexin, ampicillin, trimethoprim, co-trimoxazole and tetracycline. The most effective antibiotics were nalidixic acid, gentamicin and amoxicillin-clavulanic acid.

Adolescent↗
PubMed1999

Contrast material and gallbladder kinetics: implications for same day sonography after intravenous pyelography or CT scanning.

Sonographic examination of the gallbladder has allowed us to study the effects of various substances on this organ. A prospective study involving 77 patients was undertaken to evaluate the effects of intravenous or oral contrast agents on gallbladder volume changes in patients without known gallbladder disease. A mean volume after contraction of 24.8% was observed after administration of intravenous contrast agent (P < 0.01) and of 31.9% after oral administration (P < 0.01). This phenomenon of contraction of the gallbladder should therefore be recognized when sonographic or computed tomographic evaluation of the gallbladder is undertaken after imaging procedures that use radiographic contrast agents either intravenously or orally.

Administration, Oral↗
PubMed1998

The effect of transforming growth factor beta one (TGF-beta 1) on wound healing, with or without barrier membranes, in a Class II furcation defect in sheep.

The purpose of this study was to analyse the effect of TFG-beta 1 on wound healing in standardized Class II furcation defects of 48 mandibular second premolar teeth in 24 sheep. The experimental design included a control group (carrier only, 25% pluronic F-127), and 2 experimental groups: group A (80 micrograms/ml TGF-beta 1 + carrier) and group B (80 micrograms/ml TGF-beta 1 + carrier covered with a barrier membrane). Sheep were killed either 2 wk or 6 wk after surgery. Mesiodistal sections of the decalcified specimens were quantified histologically using stereology. Percentage volumes of regenerated bone, fibrous connective tissue and cementum were calculated for each furcation defect. Mean values were analysed using multiple ANOVA; p values were calculated using paired and unpaired Student's t-tests. After 2 wk there was more bone in group B than either of the other 2 groups, but this was not statistically significant. By 6 wk more bone was present in group A than in the control group (p < 0.02) and also in group B when compared with both group A and the control group (p < 0.02 and p < 0.44), respectively. In the 4 wk between sampling significantly more bone had formed (group A < 0.05 and group B p < 0.003, respectively). A negative correlation existed between volumes of bone and fibrous connective tissue and no significant differences between the volumes of cementum were evident between any of the groups. This study demonstrated that TGF-beta 1 encouraged bone regeneration in Class II furcation defects in sheep, an effect enhanced by the presence of a barrier membrane. This is the first report on the use of TGF-beta 1 in conjunction with GTR in periodontal defects.

Alveolar Process↗
PubMed1998

Identification of missense and truncating mutations in the BRCA1 gene in sporadic and familial breast and ovarian cancer.

The cloning of the breast and ovarian cancer susceptibility gene, BRCA1, allows direct estimation of the proportion of these cancers in the general population which can be attributed to germline mutations in this gene. We have used a combination of SSCP, heteroduplex analysis, and chemical cleavage of mismatch to screen the BRCA1 gene for mutations in the germline of 42 patients with breast or ovarian cancer who either have a moderate family history of these cancers, or have no family history of malignancy but a very early onset of the disease. A total of 30 sequence variants were observed, eight of which have not been described previously. Three sequence changes detected by chemical cleavage or heteroduplex analysis were missed by SSCP. The variants included 13 missense mutations, which were assessed for their pathogenic implications. Two of these (M18T and A1708E) are nonconservative substitutions which are located in evolutionarily conserved regions of the gene: M18T lies just upstream of the RING finger motif, and A1708E abolishes the transcriptional transactivation activity of the carboxy-terminal region of BRCA1. Mutations were observed in eight patients overall (19.0%), and protein-truncating mutations occurred in five of 27 (18.5%) families with 1-3 cases of breast or ovarian cancer. The data suggest that a significant proportion of patients with a modest or no family history of these cancers may carry germline mutations in BRCA1.

Adult↗