PubMed Health⌕ Search

Biomedical subjects

A Alwan

Publications and source records attributed to A Alwan.

13 recordsLinked to original sources
PubMed2005

Current concepts in screening for noncommunicable disease: World Health Organization Consultation Group Report on methodology of noncommunicable disease screening.

Screening people for serious diseases is receiving increasing attention as studies demonstrates the potential benefits of early detection and early intervention in preventing morbidity and mortality. Screening tests are available for some of the most important noncommunicable diseases, including cardiovascular disease, type 2 diabetes and several site-specific cancers. However, screening guidelines for cardiovascular disease, cancers and diabetes vary within and between countries because many national and international organizations are developing their own guidelines. There is a need to address the issue of screening for disease, with an emphasis on providing accurate and practical information relevant to all countries. This report arose from a Consultation Group meeting held at WHO headquarters in Geneva. It presents an examination of the principles of screening with an emphasis on noncommunicable disease prevention and control policy.

Humans↗
PubMed2000

Gene expression in an intact ex-vivo skin tissue model following percutaneous delivery of cationic liposome-plasmid DNA complexes.

The skin represents an attractive site for the localised gene therapy of dermatological pathologies and as a potential antigen bioreactor following transdermal delivery. Potential also exists for the gene therapy of skin as a cosmetic intervention. The most exploited non-viral gene delivery system involves the complexation of cationic liposomes with plasmid DNA (pDNA) to form lipid:pDNA vectors that protect the DNA from nuclease-mediated degradation and improve transgene-cell interactions. Despite numerous studies examining the potential for these vectors in delivering genes to a variety of keratinocyte models, investigations into the topical application of such complexes to intact skin tissue is limited. This ex-vivo study, conducted with intact skin tissue derived from hairless mice, provides quantitative confirmation that topical administration of cationic lipid:pDNA complexes can mediate uptake and expression of reporter pDNA (33-fold higher compared with control) in viable epidermal tissue. The ex-vivo study design provides for intact skin tissue that has not been subjected to depilatory procedures of potential detriment to stratum corneum barrier function, and can be utilised for the quantitative and efficient examination of a potentially wide range of non-viral gene vectors designed for epidermal expression.

Administration, Topical↗
PubMed2000

Serum haptoglobin: an objective indicator of experimentally-induced Salmonella infection in calves.

Experimental models of Salmonella -induced gastroenteritis have previously relied on crude subjective clinical markers of infection to assess disease severity. The aim of this study was to investigate the possibility that changes in serum levels of the acute phase protein, haptoglobin, may be used as an objective, quantitative measurement of infection. Eight 3- to 4-week-old animals were challenged with a mixture of three Salmonella serotypes containing 6 x 10(10)bacteria and compared with five animals given a placebo preparation. Animals were monitored and characteristic clinical symptoms of infection; diarrhoeal scores, morbidity scores and rectal temperature, were recorded. Serum samples, from both animal groups, taken prior to challenge and again on days 1, 3, and 5 post-challenge, were analysed for haptoglobin levels using a direct serum binding assay. Prior to challenge, all 13 animals had normal levels of haptoglobin in their serum. By day 3 post-challenge six of eight animals challenged with Salmonella had abnormal serum haptoglobin levels (median level = 212 microg ml(-1)), while haptoglobin levels remained normal in placebo-challenged animals (median level = 0 microg ml(-1)). The change in haptoglobin levels during the 5-day observation period was statistically significant in the Salmonella -challenged animals (P = 0.0003, H = 16.477). Serum haptoglobin levels showed a statistical correlation with clinical measures of disease severity; diarrhoeal scores (P = 0.0015, H =8. 988), morbidity scores (P = 0.0004, H = 15.711) and rectal temperature (P = 0.0001, Z = 4.304). Thus, serum haptoglobin levels closely reflect the clinical symptoms of infection and are therefore a useful marker of infection severity in salmonellosis in calves.

Animals↗
PubMed2000

Acoustic modeling of American English /r/.

Recent advances in physiological data collection methods have made it possible to test the accuracy of predictions against speaker-specific vocal tracts and acoustic patterns. Vocal tract dimensions for /r/ derived via magnetic-resonance imaging (MRI) for two speakers of American English [Alwan, Narayanan, and Haker, J. Acoust. Soc. Am. 101, 1078-1089 (1997)] were used to construct models of the acoustics of /r/. Because previous models have not sufficiently accounted for the very low F3 characteristic of /r/, the aim was to match formant frequencies predicted by the models to the full range of formant frequency values produced by the speakers in recordings of real words containing /r/. In one set of experiments, area functions derived from MRI data were used to argue that the Perturbation Theory of tube acoustics cannot adequately account for /r/, primarily because predicted locations did not match speakers' actual constriction locations. Different models of the acoustics of /r/ were tested using the Maeda computer simulation program [Maeda, Speech Commun. 1, 199-299 (1982)]; the supralingual vocal-tract dimensions reported in Alwan et al. were found to be adequate at predicting only the highest of attested F3 values. By using (1) a recently developed adaptation of the Maeda model that incorporates the sublingual space as a side branch from the front cavity, and by including (2) the sublingual space as an increment to the dimensions of the front cavity, the mid-to-low values of the speakers' F3 range were matched. Finally, a simple tube model with dimensions derived from MRI data was developed to account for cavity affiliations. This confirmed F3 as a front cavity resonance, and variations in F1, F2, and F4 as arising from mid- and back-cavity geometries. Possible trading relations for F3 lowering based on different acoustic mechanisms for extending the front cavity are also proposed.

Humans↗
PubMed1999

Phenoxybenzamine in the management of neuropathic bladder following spinal cord injury.

BACKGROUND: The present study aims to show the clinical and urodynamic effects of phenoxybenzamine on the neuropathic bladder of spinal cord-injured patients who failed to be free of catheter by attaining satisfactory voiding function, despite initial bladder training. METHODS: Forty-six spinal cord-injured patients were subjected to pharmacological manipulation with phenoxybenzamine. It was used as an adjunct in the management of neuropathic bladder dysfunction that caused failure of the bladder to empty, by tapping or crede to achieve satisfactory residual urine volume of < 100 mL. Phenoxybenzamine was started with a dose of 10 mg daily, increased by 10 mg every 3 days to a dose of 30 mg daily; this was maintained from 3 weeks to 6 months (mean: 39 days). The pre-treatment residual urine volume ranged between 100 and 1050 mL (mean: 360 mL). Follow-up periods ranged between 12 and 36 months (mean: 16 months). RESULTS: Five patients (11%) were excluded due to either inadequate treatment or inadequate follow-up. Nineteen patients (41%) with reflex (upper motor neurone) bladders showed improvement of bladder evacuation. There was a reduction of the maximum urethral closure pressure, which ranged between 10 and 32 cm of water (mean: 22 cm). Twenty-two patients (48%) did not respond, requiring other measures to be taken which included transurethral surgery (n = 19). Nine of the failures involved areflex (lower motor neurone) bladders, and seven failures involved reflex bladders with an extremely tight outlet and urethral closure pressure of > 50 cm of water. Six failures involved reflex bladders that were lacking strong enough detrusor contractions to attain a balanced bladder responsive to abdominal tapping; response was achieved by administration of a parasympatheticomimetic drug. Neuropathic bladders with uninhibited detrusor contractions responded well to phenoxybenzamine. CONCLUSIONS: Phenoxybenzamine proved useful in reducing bladder outlet resistance after spinal cord injury, provided that detrusor bladder contractions were present. It is useful in controlling detrusor-sphincter dyssynergia and autonomic hyperreflexia. It was not useful in areflex bladders, perhaps due to the development of spasticity of the striated muscle component of the external sphincter. The presence of bladder neck (internal sphincter) dysfunction may modify or abolish its effect.

Adolescent↗
PubMed1997

Prostate volume and cancer in screening programs.

BACKGROUND: Prostate cancer screening is studied in a randomized trial in Antwerp, Belgium. The case group receives three screening tests (DRE, TRUS, and PSA). Intermediate evaluation shows that only 1/3 of the biopsy results is positive (35/125). The proposed analysis identifies variables that determine the biopsy outcome. METHODS: Multiple logistic regression analysis is used to regress biopsy results (n = 125) by age (60-74), PSA, PSA-D, prostate volume, TRUS, and DRE. Continuous variables are transformed into quartile values. Robustness of the outcome is tested with ROC and sensitivity analysis on age. RESULTS: Biopsy outcomes are best explained (82.3%) by PSA, DRE, and DRE related to volume. Volume is more sensitive than age to explain the biopsy result. PSA-D, instead of PSA, does not procure more precise information when a high PSA cut-off level is used. Restricting the analysis to the 60-70-year-old age group shows that volume is more sensitive. ROC-analysis confirms the findings. CONCLUSIONS: When performing prostate cancer multitest screening among a wide age range, the use of uniform screening criteria is difficult to accept due to differences in prostate volume. Logistic regression analysis is an appropriate method to identify cut-off levels for prostate volume.

Aged↗
PubMed1997

Toward articulatory-acoustic models for liquid approximants based on MRI and EPG data. Part II. The rhotics.

Magnetic resonance images of the vocal tract during sustained production of [symbol: see text] by four native American English talkers are employed for measuring vocal-tract dimensions and for morphological analysis of the 3D vocal tract and tongue shapes. Electropalatography contact profiles are used for studying inter- and intra-talker variabilities. The vocal tract during the production of [symbol: see text] appears to be characterized by three cavities due to the presence of two supraglottal constrictions: the primary one in the oral cavity, and a secondary one in the pharyngeal cavity. All subjects show a large volume anterior to the oral constriction, which results from an inward-drawn tongue body, an anterior tongue body that is characterized by convex cross sections, and a concave posterior tongue body shape. Inter-subject variabilities are observed in the oral-constriction location and the way the constriction is formed. No systematic differences are found between the 3-D vocal tract and tongue shapes of word-initial and syllabic [symbol: see text]s. Tongue-shaping mechanisms for these sounds and their acoustic implications are discussed.

Adult↗
PubMed1994

Hereditary disorders in the Eastern Mediterranean Region.

Hereditary diseases and congenital malformations have been reported to affect 2-5% of all live births. Available evidence suggests that genetic disorders are equally important also in countries of the Eastern Mediterranean Region. Considerable achievements have been made over the last two decades in controlling communicable diseases in the region. Concurrently, there has been a mounting awareness of the increasing importance of hereditary disorders. Certain genetically determined diseases such as the haemoglobinopathies and enzymopathies are extremely common in the region and the need to initiate public health measures for their control is increasingly being recognized. The following factors may contribute to the elevated prevalence of genetically determined disorders: the high consanguinity rates; the high frequency of haemoglobinopathies and glucose-6-phosphate dehydrogenase deficiency; the trend of continuing to bear children up to menopause; the general lack of public awareness about genetic diseases; and the dearth of genetic services in the region. These and some other related issues are discussed in detail in this review article.

Chromosome Aberrations↗
PubMed1992

Diabetes in the eastern Mediterranean region.

Socioeconomic development and changes in lifestyles have been accompanied by the emergence of diabetes as a major problem in Eastern Mediterranean countries, but reliable epidemiological data are still scarce and comparability is generally poor. For non-insulin-dependent diabetes (NIDDM) in adults, risk is higher in urban than in rural subjects, and in all populations prevalence increases with advancing age. Whereas several surveys have reported prevalence of the order of 5%, a recent national survey in Oman, which used the full WHO criteria for diagnosis, based upon the 2 hour blood glucose concentration after a 75 g oral glucose load in all subjects, reported a prevalence of diabetes of 10% in those aged 20 years and over. A further 8% of men and 13% of women had impaired glucose tolerance (IGT). Insulin-dependent diabetes (IDDM) was reported to be considerably rarer in Kuwait than in Europe and North America, but some more recent data suggest variability in frequency within the region. IDDM is frequently accompanied by ketoacidosis at diagnosis. For NIDDM, 75% of cases are associated with obesity. Long-term complications appear to occur to the same extent as in Western countries. A recent WHO Task Force meeting has set goals and targets for diabetes prevention and control within the Eastern Mediterranean Region.

Adolescent↗
PubMed1979

[Percutaneous thermocoagulation of sacral roots (author's transl)].

Following spinal cord lesions, signs of spasticity may be observed on bladder with decreased capacity and urinary leaks. We have attempted to associate the inocuity of anesthetic blocks and the selective precision of microsurgical rhizotomies by percutaneous thermocoagulation of sacral roots. Bilateral 53 root coagulation, under Rx control, vesical pressure monitoring and stimulation tests, is ususally efficient. Authors report the technic and the results of this simple method about the first nine cases with more than one year of follow up.

Adolescent↗