PubMed Health⌕ Search

Biomedical subjects

S N Khan

Publications and source records attributed to S N Khan.

At least 19 recordsLinked to original sources
PubMed2006

Mutations of human TMHS cause recessively inherited non-syndromic hearing loss.

BACKGROUND: Approximately half the cases of prelingual hearing loss are caused by genetic factors. Identification of genes causing deafness is a crucial first step in understanding the normal function of these genes in the auditory system. Recently, a mutant allele of Tmhs was reported to be associated with deafness and circling behaviour in the hurry-scurry mouse. Tmhs encodes a predicted tetraspan protein of unknown function, which is expressed in inner ear hair cells. The human homologue of Tmhs is located on chromosome 6p. OBJECTIVE: To determine the cause of deafness in four consanguineous families segregating recessive deafness linked to markers on chromosome 6p21.1-p22.3 defining a novel DFNB locus. RESULTS: A novel locus for non-syndromic deafness DFNB67 was mapped in an interval of approximately 28.51 cM on human chromosome 6p21.1-p22.3. DNA sequence analysis of TMHS revealed a homozygous frameshift mutation (246delC) and a missense mutation (Y127C) in affected individuals of two families segregating non-syndromic deafness, one of which showed significant evidence of linkage to markers in the DFNB67 interval. The localisation of mTMHS in developing mouse inner ear hair cells was refined and found to be expressed briefly from E16.5 to P3. CONCLUSIONS: These findings establish the importance of TMHS for normal sound transduction in humans.

Alleles↗
PubMed2005

Complications of temporary and definitive external fixation of pelvic ring injuries.

OBJECTIVES: To determine the incidence of complications of external fixation in pelvic ring injuries, comparing fixator use for temporary and definitive treatment. DESIGN: Retrospective case-note review. SETTING: A regional centre for pelvic trauma in the UK. PATIENTS: 100 consecutive patients. INTERVENTION: All patients were treated with pelvic external fixation for a pelvic ring injury. RESULTS: In 52 patients, external fixation was intended for use as the definitive treatment of the pelvic ring injury and was maintained for a mean duration of 60 days (17-113). In 48 patients, it was used temporarily for a mean duration of 8 days (1-20) before internal fixation of the pelvic ring. The complication rate for definitive and temporary fixators was 62 and 21%, respectively. Pin-site infection occurred in 50% of definitive fixators and 13% of temporary fixators but rarely led to more serious complications. In five patients, the definitive management was changed as a result of a complication of the external fixator. The commonest cause for revision of either fixator was aseptic pin loosening. Revision for loose pins in eight patients was associated with the use of two pins in each iliac crest rather than three. CONCLUSIONS: The temporary use of external fixation is safe and effective, but use for definitive treatment is associated with a high rate of infection and aseptic pin loosening.

Adolescent↗
PubMed2004

Cerebrospinal fluid drainage for thoracic and thoracoabdominal aortic aneurysm surgery.

BACKGROUND: During aortic aneurysm surgery, cross-clamping can lead to inadequate blood supply to the spinal cord resulting in neurological deficit. Cerebrospinal fluid drainage (CSFD) may increase the perfusion pressure to the spinal cord and hence reduce the risk of ischaemic spinal cord injury. OBJECTIVES: To determine the effect of CSFD during thoracic and thoracoabdominal aortic aneurysm (TAAA) surgery on the risk of developing spinal cord injury. SEARCH STRATEGY: The reviewers searched the Cochrane Peripheral Vascular Diseases Group Specialised Trials Register (last searched October 2003), the Cochrane Central Register of Controlled Trials (CENTRAL) database (last searched Issue 4, 2003), MEDLINE and EMBASE, and reference lists of relevant articles. Recent conference proceedings were scanned. SELECTION CRITERIA: Randomised trials involving CSFD during thoracic and TAAA surgery. DATA COLLECTION AND ANALYSIS: Both reviewers assessed the quality of trials independently. One reviewer (SNK) extracted data and the other reviewer (GS) verified the data. MAIN RESULTS: Three trials, with a total of 287 participants operated on for type I or II TAAA, were included. In the first trial of 98 patients, neurological deficits in the lower extremities occurred in 14 (30%) CSFD and 17 (33%) controls. The deficit was observed within 24 hours of the operation in 21 (68%), and from 3 to 22 days in 10 (32%). CSFD did not have a significant benefit in preventing ischaemic injury to the spinal cord. The second trial of 33 patients used a combination of CSFD and intrathecal papaverine. It showed a statistically significant reduction in the rate of postoperative neurological deficit (p = 0.039), compared to controls. Analysis was undertaken after only one third of the estimated sample size had entered the trial. In the third trial TAAA repair was performed on 145 patients. CSFD was initiated during the operation and continued for 48 hours after surgery. Paraplegia or paraparesis occurred in 9 of 74 patients (12.2%) in the control group versus 2 of 82 patients (2.7%) with CSFD (p = 0.03). Overall, CSFD resulted in an 80% reduction in the relative risk of postoperative deficits. Meta-analysis showed an odds ratio (OR) of 0.48 (0.25 to 0.92; confidence interval (CI) 95%). For CSFD trials only OR was 0.57 (0.28 to 1.17) and for intention-to-treat in CSFD only studies OR remained unchanged. REVIEWER'S CONCLUSIONS: There are limited data supporting the role of CSFD in thoracic and thoracoabdominal aneurysm surgery for prevention of neurological injury. Further clinical and experimental studies are indicated.

Aortic Aneurysm, Abdominal↗
PubMed2004

Mutations of ESPN cause autosomal recessive deafness and vestibular dysfunction.

We mapped a human deafness locus DFNB36 to chromosome 1p36.3 in two consanguineous families segregating recessively inherited deafness and vestibular areflexia. This phenotype co-segregates with either of two frameshift mutations, 1988delAGAG and 2469delGTCA, in ESPN, which encodes a calcium-insensitive actin-bundling protein called espin. A recessive mutation of ESPN is known to cause hearing loss and vestibular dysfunction in the jerker mouse. Our results establish espin as an essential protein for hearing and vestibular function in humans. The abnormal vestibular phenotype associated with ESPN mutations will be a useful clinical marker for refining the differential diagnosis of non-syndromic deafness.

Adolescent↗
PubMed2004

Long-term disability after neck injury. a comparative study.

Claims for personal injury after whiplash injury cost the economy of the United Kingdom more than pound 3 billion per year, yet only very few patients have radiologically demonstrable pathology. Those sustaining fractures of the cervical spine have been subjected to greater force and may reasonably be expected to have worse symptoms than those with whiplash injuries. Using the neck disability index as the outcome measure, we compared pain and functional disability in four groups of patients who had suffered injury to the cervical spine. After a mean follow-up of 3.5 years, patients who had sustained fractures of the cervical spine had significantly lower levels of pain and disability than those who had received whiplash injuries and were pursuing compensation (p < 0.01), but had similar levels to those whiplash sufferers who had settled litigation or had never sought compensation. Functional recovery after neck injury was unrelated to the physical insult. The increased morbidity in whiplash patients is likely to be psychological and is associated with litigation.

Accidents, Traffic↗
PubMed2001

Motives underlying food choice: dentists, porters and dietary health promotion.

OBJECTIVE: Differences in dental decay and disease amongst socioeconomic groups are thought to derive, in part, from variations in dietary practices and differences in education. The aim of this exploratory study was to examine whether differences in motivating factors affecting food choice could be found in a comparison of two groups at very different ends of the social spectrum: dentists and porters/cleaners. DESIGN: A convenience sample of 100 people (51 porters/cleaners and 49 dentists) working in the dental school at a university in the North West of England were approached to interview face-to-face and complete the Food Choice Questionnaire (FCQ), a previously validated measure designed to assess nine main factors relevant to peoples' food choices. A sample size of 100 was chosen because it was adequate to test validity (using a two-group Chi-square test with a 0.050 two sided significance). RESULTS: Findings were analysed using independent sample t-test and multiple linear regression. Results indicated significant differences between porters/cleaners and dentists in terms of their motives for food choice on six of the nine FCQ factors. These included convenience (p < 0.001), natural content (p < 0.05), price (p < 0.005), familiarity (p < .0001), mood (p < 0.03) and ethical concern (p < 0.01). Porters/cleaners tended to rate the factors covenience, price, mood and familiarity more highly, whereas dentists did the same for natural content and ethical concern. CONCLUSIONS: Awareness of the differences in motivational factors affecting food choice between different social groups is important to dental practitioners who are being taught to play an increasing role in health promotion. If dental practitioners are to partake meaningfully in such a role, it is necessary for them to be aware not only of their own motives in food selection, but also of the way in which those motives may differ from those of their clients.

Adult↗
PubMed2001

Rehabilitation for limb salvage patients: kinesiological parameters and psychological assessment.

Osteosarcoma is the most frequently occurring primary malignant tumor of bone, especially in adolescence. Treatment involves either limb salvage surgery or amputation with neoadjuvant chemotherapy. This review article discusses the current treatment modalities for osteosarcoma and also compares the gait patterns and psychosocial profiles of patients treated with either limb salvage surgery or amputation for osteosarcoma. Contemporary orthopedic literature on therapeutic options for osteosarcoma patients is reviewed. Background information on the basic principles of kinesiology, with emphasis on studies of gait pattern differences among patients treated with limb salvage versus amputation, is presented. Finally, several studies of the psychologic profiles of patients after these two procedures for osteosarcoma are reviewed. Trends in contemporary orthopedic literature suggest that functional outcomes, in terms of kinesiologic parameters, are comparable for patients treated with either limb salvage or amputation. Both sets of patients reported quality-of-life problems, including difficulty retaining health insurance and finding appropriate employment, social isolation, and poor self-esteem. The management of patients with osteosarcoma includes not only an individualized surgical plan for each patient but also includes awareness of the patients' psychologic and social needs after surgery.

Adaptation, Psychological↗
PubMed2001

Demineralized bone matrix, bone morphogenetic proteins, and animal models of spine fusion: an overview.

Preclinical investigations on the use of bone morphogenetic proteins (BMP) in the spine have yielded promising results. This has led to the preliminary introduction of these growth factors in controlled clinical trials. Initial data made available suggest that these differentiating factors will play a major role in the treatment of spinal disorders in the future. This article reviews key preclinical studies and their results that formed the basis for introduction into clinical trials. Non-primate and non-human primate models of spine fusion with BMP are reviewed objectively, and important issues regarding carrier, dose, and site of implantation are discussed. Finally, exciting new gene therapy research is discussed, with comments made on its applicability for the future.

Animals↗
PubMed2001

A multi-center study in order to further define the molecular basis of beta-thalassemia in Thailand, Pakistan, Sri Lanka, Mauritius, Syria, and India, and to develop a simple molecular diagnostic strategy by amplification refractory mutation system-polymerase chain reaction.

The spectrum of the beta-thalassemia mutations of Thailand, Pakistan, India, Sri Lanka, Mauritius and Syria has been further characterized by a multi-center study of 1,235 transfusion-dependent patients, and the mutations discovered used to assess the fidelity of a simple diagnostic strategy. A total of 44 beta-thalassemia mutations were identified either by allele-specific oligonucleotide hybridization, amplification with allele-specific primers, or DNA sequencing of amplified product. The results confirm and extend earlier findings for Thailand, Pakistan, India, Mauritius and Syria. This is the first detailed report of the spectrum of mutations for Sri Lanka. Two novel mutations were identified, codon 55 (-A) and IVS-I-129 (A-->C), both found in Sri Lankan patients. Two beta-thalassemia mutations were found to coexist in one beta-globin gene: Sri Lankan patients homozygous for the beta0 codon 16 (-C) frameshift were also homozygous for the beta+ codon 10 (C-->A) mutation. Studies of Sri Lankan, Pakistani, and Indian carriers suggest the codon 10 (C-->A) mutation is just a rare polymorphism on an ancestral allele, on which the beta0 codon 16 (-C) mutation has arisen. Each country was found to have only a few common mutations accounting for 70% or more of the beta-thalassemia alleles. A panel of primers to diagnose the majority of the mutations by the amplification refractory mutation system was developed, enabling a simple molecular diagnostic strategy to be introduced for each country participating in the multi-center study.

Asia↗
PubMed2001

Sudden sensorineural hearing loss after spinal surgery under general anesthesia.

Two patients, ages 72 and 71, who underwent lumbar decompressive surgery for spinal stenosis, were evaluated for postoperative sudden sensorineural hearing loss (SSHL). After two uncomplicated spinal procedures, both patients developed SSHL immediately after surgery. Hearing loss was moderate to profound in these two patients. None of the patients had a significant otologic history. Nitrous oxide administration, Valsalva maneuvers during general anesthesia, and transient drops in cerebrospinal fluid pressure stemming from spinal decompression may, in some combination, lead to an implosive force on the inner ear, causing SSHL. Further causes of postlumbar surgery SSHL may include microemboli or viral infections. SSHL is a rare but possible complication after nonotologic, noncardiac bypass surgery; only 26 cases of SSHL after this surgery have been reported. We encourage the continued reporting of sudden sensorineural hearing loss after spinal surgery.

Aged↗
PubMed2001

Predictors of functional outcome in elderly patients undergoing posterior lumbar spine surgery.

To ascertain the predictors of functional outcome in elderly patients undergoing posterior lumbar spinal decompression and fusion, a modified low back outcome score questionnaire survey in 83 elderly patients (49 men, 34 women) was carried out at our hospital. The average follow-up was 35.8 months (range: 22-57 months). The outcomes were as follows: excellent to good, 83%; fair, 7%; and poor, 10%. Multiple regression analysis revealed that significant predictors of unfavorable outcome included coexistence of other bone and joint degenerative disorders (p < 0.001) and history of heart disease (p < 0.01). Patients who had undergone previous lumbar surgery had significantly lower modified low back outcome score than those without previous lumbar spine surgery (p < 0.05). The modified low back outcome score questionnaire system is a reliable method in elderly patients.

Aged↗
PubMed2001

Bisphosphonate therapy in fibrous dysplasia.

Fibrous dysplasia is proliferation of fibrous tissue within the bone marrow causing osteolytic lesions and pathologic fractures. Recently, second generation bisphosphonates have shown promise in the treatment of patients with fibrous dysplasia. In the current study, six patients with fibrous dysplasia were treated with either oral alone or oral and intravenous bisphosphonates. The participants were observed for changes in N-telopeptide, pain score, and radiographic changes. In the current study, the combination bisphosphonate therapy diminished pain, prevented fractures, lowered N-telopeptide values, and led to partial resolution of fibrous dysplasia lesions.

Administration, Oral↗
PubMed2000

Usher syndrome 1D and nonsyndromic autosomal recessive deafness DFNB12 are caused by allelic mutations of the novel cadherin-like gene CDH23.

Genes causing nonsyndromic autosomal recessive deafness (DFNB12) and deafness associated with retinitis pigmentosa and vestibular dysfunction (USH1D) were previously mapped to overlapping regions of chromosome 10q21-q22. Seven highly consanguineous families segregating nonsyndromic autosomal recessive deafness were analyzed to refine the DFNB12 locus. In a single family, a critical region was defined between D10S1694 and D10S1737, approximately 0.55 cM apart. Eighteen candidate genes in the region were sequenced. Mutations in a novel cadherin-like gene, CDH23, were found both in families with DFNB12 and in families with USH1D. Six missense mutations were found in five families with DFNB12, and two nonsense and two frameshift mutations were found in four families with USH1D. A northern blot analysis of CDH23 showed a 9.5-kb transcript expressed primarily in the retina. CDH23 is also expressed in the cochlea, as is demonstrated by polymerase chain reaction amplification from cochlear cDNA.

Alleles↗
PubMed2000

Bone growth factors.

Osteoblastic culture models, experimental, and clinical models have revealed that bone growth factors influence cellular activity. Growth factors including bone morphogenetic proteins, transforming growth factor beta, platelet-derived growth factor, insulin-like growth factors I and II, and acidic and basic fibroblast growth factors, are powerful tools for fracture healing and bone grafting. Understanding the role that bone growth factors play in bone repair is necessary to apply these factors in a clinical setting.

Animals↗
PubMed2000

Clinical applications of bone graft substitutes.

Autogenous bone grafting remains the gold standard for osseous reconstruction in clinical practice. It is associated with several limitations. The search for an alternative bone graft substitute with combined osteoinductive, osteoconductive, and osteogenic properties continues. This article highlights the properties of the various bone grafting materials currently available and discusses their efficacy in clinical practice.

Animals↗
PubMed2000

The use of growth factors in cartilage repair.

Articular cartilage, which enables smooth gliding of joints during skeletal motion, is vulnerable to injuries and degenerative diseases over time. Bone growth factors have a role in the preservation of the cartilage matrix. This article reviews the potential to treat cartilage damage for bone morphogenetic proteins, insulin-like growth factors, hepatocyte growth factor, basic fibroblast growth factor, and transforming growth factor beta.

Animals↗
PubMed2000

Current concepts in intervertebral disc restoration.

A current focus of treatment for degenerative disk disease is the restoration of the intervertebral disk. This article summarizes the structure and function of the intervertebral disk, the pathogenesis of its degeneration, and the clinical relevance of degenerative disk disease. Current literature relating to intervertebral disk replacement and regeneration is reviewed.

Animals↗