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Biomedical subjects

A Akin

Publications and source records attributed to A Akin.

At least 19 recordsLinked to original sources

Time-frequency methods for detecting spike activity of stomach.

It has been hypothesised by many researchers that the spike activity signals of the stomach are responsible for triggering peristaltic contractions. Since most gastric motility disorders include an abnormality in the contraction pattern, it is very important to access this information non-invasively. The aim in this study is to use abdominal electrogastrogram (EGG) signals to detect the spike activity signals generated by the serosa of the stomach, and hence provide clinicians with a better method to monitor the motility state of the stomach. Through second and third-order spectral estimations performed on the serosal data obtained from canine experiments, it was concluded that the spike activity in serosal signals occupies a frequency range of 50-80 cycles per minute. An increase in this frequency range during strong antral contractions was observed both in the serosal and cutaneous power spectra. By using the 'continuous wavelet transform' with respect to a modified Morlet wavelet, the spike activity signals generated from the serosa of the stomach can be detected and quantified in time from the cutaneous EGG records. During phase III contraction episodes, a detection accuracy of up to 96% from the cutaneous EGG recordings was calculated based on the scored serosal spike activities simultaneously recorded.

Animals↗

Evaluation of gastrointestinal involvement of Behçet's disease by nuclear medical techniques.

To evaluate the value of nuclear medicine procedures in the diagnosis of gastrointestinal involvement of Behcet's disease in asymptomatic patients, Tc-99m human immunoglobulin (HIG) and Tc-99m leucocyte (LC) whole body scintigraphies were performed on 30 patients with major symptoms of the disease. Comparison of the results with other diagnostic techniques showed that Tc-99m HIG whole body scanning can be a useful diagnostic aid before the disease becomes clinically active in the gastrointestinal system.

Adult↗

Amplification and cloning of infectious bursal disease virus genomic RNA segments by long and accurate PCR.

Improved methods of reverse transcription, polymerase chain reaction (PCR) amplification, and cloning of full-length coding region of both strands of infectious bursal disease virus (IBDV) variant strain E genome were developed. Denaturation of IBDV RNA by heat in the presence of primers and use of a reverse transcriptase lacking RNase-H activity produced full-length coding region and partial non-coding region cDNA copies of the viral genomic segments. Digestion of the RNA component of RNA-cDNA hybrids by RNase-H followed by long and accurate PCR (LA-PCR) amplification of IBDV cDNA in a single step resulted in the synthesis of 3182 base-pairs (bp) of segment A and 2777 bp of segment B cDNA copies of IBDV genome. The resulting amplicons were successfully cloned and sequenced revealing their identity of IBDV. The LA-PCR method can be utilized for the amplification and cloning of the other IBDV strains or isolates and will greatly enhance the availability of sequence information or infectious cDNA copies of IBDV.

Animals↗

Visual symptoms and G-LOC in the operational environment and during centrifuge training of Turkish jet pilots.

BACKGROUND: High-performance fighter aircraft produce high-sustained +Gz forces with rapid onset rates. Because of this G-producing capability, military jet pilots are subjected to physiological stress, which may lead to visual disturbances and G-induced loss of consciousness (G-LOC). Although visual disturbances are very common in jet flights, G-LOC is relatively rare but more dangerous. The frequency and causes of G-LOC need to be determined in the interest of flight safety. METHODS: Part I. A survey was conducted on Turkish jet pilots to reveal the incidence of symptoms due to +Gz acceleration. Anonymous questionnaires were given to F-16, F-4, and F-5 pilots. They consisted of inquiries about the occurrence of visual symptoms and/or G-LOC during +Gz acceleration in the operational environment. Part II. During the years 1992-1996, 486 F-16, 801 F-4, and 256 F-5 fighter pilots underwent high "G" training at Turkish Aerospace Medical Center and they were assessed in terms of G-LOC rates. RESULTS: Part I. A total of 325 pilots who flew T-37 in undergraduate pilot training (UPT) answered the questionnaire. The pilots were divided into 3 groups according to the types of aircraft, which they fly now: 116 F-16, 182 F-4, and 27 F-5 pilots. A total of 311 pilots (95.7%) reported having experienced greyouts and/or blackouts. With 25 pilots (7.7%) experiencing G-LOC, the G-LOC frequency according to the type of aircraft was: 5.2% (T-37) [in UPT]; 4.3% (F-16), 1.6% (F-4), and 0% (F-5). Part II. In centrifuge training, the incidence of G-LOC in pilots of the various types of aircraft were: 12% (F-16), 6.4% (F-4), and 8.6% (F-5). CONCLUSIONS: Centrifuge training reduces G-LOC rates of subsequent centrifuge training; and it is hoped might reduce the G-LOC rate in the operational environment. Almost all jet pilots reported having experienced +Gz related visual symptoms, but G-LOC seems to be a more common problem for pilots who fly rapid onset rate aircraft than pilots who fly high "G" capable but lower G onset rate aircraft.

Acceleration↗

A ribozyme targeted to RNA polymerase gene of infectious bursal disease virus effectively cleaves and inhibits expression of the viral gene product.

Five hammerhead-type ribozymes were designed and cloned to cleave infectious bursal disease virus (IBDV) RNA and inhibit protein synthesis from cloned full-length viral cDNA genes. Two ribozymes (R1 and R2) were directed to the large viral RNA segment gene and three ribozymes (R3, R4, and R5) were directed to the small viral RNA segment gene. Targets for the ribozymes were produced from cloned full-length coding regions of both small and large viral RNA segment genes. Ribozymes and their corresponding targets were synthesized as in vitro transcripts. Despite several attempts at different temperatures, no cleavage of viral RNA transcripts with four of the ribozymes (R1, R2, R3, and R5) was observed. One of the ribozymes, R4, was effective in cleaving the viral RNA polymerase gene transcripts in a magnesium-dependent manner. Ribozyme R4 caused 82% reduction in the synthesis of the viral RNA polymerase gene product. The inhibition was specific since there was no change in the rate of synthesis of the Escherichia coli beta-galactosidase protein. The results suggest that ribozyme R4 can be used as potential anti-IBDV agent. It was also demonstrated that the hammerhead-type ribozymes can cleave sites other than conventional GUC sequence motif as the cleavage site of ribozyme R4 had GUU motif which conformed to the NUX consensus motif.

Animals↗

A comparison of two RNA isolation methods for double-stranded RNA of infectious bursal disease virus.

Infectious bursal disease virus (IBDV), a member of the birnaviridae family, contains a bisegmented double-stranded RNA (dsRNA) genome. The segments are linked covalently at 5' termini by a large (90 kDa) viral genomic protein that migrates similar to viral RNA dependent RNA polymerase of IBDV. A proteinase K digestion based approach and acid-guanidium-phenol-chloroform (AGPC) RNA extraction method were used to extract dsRNA of IBDV from infected bursae. After extraction, dsRNA of IBDV was purified by precipitation with lithium chloride. The yield and purity of dsRNA of IBDV extracted by AGPC method was lower than that of proteinase K digestion based approach. This observation correlates with the presence of a genome-linked protein in IBDV. Although dsRNA obtained by both methods are suitable for reverse transcription-polymerase chain reaction (RT-PCR) amplification of at least up to 1201 base pairs (bp) of cDNA, dsRNA extracted by the proteinase K digestion method is more suitable than that by AGPC method for the amplification of longer fragments (1958 bp) of IBDV cDNA by PCR.

Animals↗

Male involvement in family planning in Turkey.

Many men in Turkey are motivated to use contraception and to share responsibility for family planning with their wives. About half the couples practising family planning use male-dependent methods. Men commonly use traditional methods, predominantly withdrawal, and should be treated as a specific target group in family planning programmes in order to motivate them to use modern methods.

Adolescent↗

Quantitative competitive polymerase chain reaction for detection and quantification of infectious bursal disease virus cDNA and RNA.

A polymerase chain reaction (PCR)-based method to measure complementary DNA (cDNA) and RNA levels of infectious bursal disease virus (IBDV) was developed. Quantification was achieved by quantitative competitive PCR (QC-PCR) amplification. A competitor, a deletion mutant of the wild type IBDV cDNA, was 10-fold serially diluted and co-amplified with IBDV cDNA after being reversely transcribed from the viral RNA. After agarose gel electrophoresis, staining, and densitometric scanning, the bands on the digitized images were analyzed and quantified by computer-assisted image analysis. Complementary DNA of standard, as well as variant strains, of serotype 1 IBDV was detected and quantified using the same QC-PCR procedures. The assay could measure IBDV cDNA levels ranging from 1 microgram to 45 fg and RNA levels ranging from 9 micrograms to 45 fg. The results indicated that QC-PCR is sensitive, easy to perform, and suitable for routine quantitation of IBDV cDNA or RNA levels.

Animals↗

Synthesis and structure-activity relationships of some 2,5-disubstituted benzoxazoles and benzimidazoles as antimicrobial agents.

The synthesis of a new series of 2,5-disubstitutedbenzoxazoles 5a-e, and 2,5-disubstitutedbenzimidazoles 6a-h are described in order to determine their antimicrobial activities and feasible structure-activity relationships (SAR). The synthesized compounds were tested in vitro against 3 Gram-positive, 3 Gram-negative, bacteria and a fungus Candida albicans. 5c, and 5e were found most active than the others against Bacillus subtilis at a MIC value of 3.12 micrograms/ml and the compounds 5e, 6a and 6e indicated significant antibacterial activity against the enterobacter Pseudomonas aeruginosae. 5a, 5c, 5d and 6d also exhibited antimycotic activity against C. albicans. The antibacterial and antimycotic activities of 5-6 are compared with several control drugs.

Anti-Bacterial Agents↗

Synthesis and microbiological activity of 5(or 6)-methyl-2-substituted benzoxazole and benzimidazole derivatives.

The synthesis and microbiological activity of a new series of 5(or 6)-methyl-2-substituted benzoxazoles (IVa-n) and benzimidazoles (Va-h) were described. The in vitro microbiological activity of the compounds was determined against gram-positive, gram-negative bacteria and the yeast Candida albicans in comparison to reference drugs. Microbiological results indicated that the derivatives possessed a broad spectrum of activity against the tested microorganisms and the compounds IVa-g, IVi-k, IVn, Vb-c and Vh showed significant activity against Pseudomonas aeruginosa having MIC values of 25 micrograms/ml, providing higher potencies than the reference drugs tetracycline and streptomycin. Moreover, the derivative 5-methyl-2-(p-chlorobenzyl)benzoazole (IVb) possessed the same potency against Candida albicans as the reference drugs oxiconazole and haloprogin having a MIC value of 6.25 mg/ml. However, none of the derivatives showed a better spectrum of activity than the reference drugs.

Anti-Bacterial Agents↗

Synthesis and microbiological activity of some novel N-(2-hydroxyl-5-substitutedphenyl)benzacetamides, phenoxyacetamides and thiophenoxyacetamides as the possible metabolites of antimicrobial active benzoxazoles.

Synthesis of some novel N-(2-hydroxyl-5-substitutedphenyl)benzacetamides, phenoxyacetamides and thiophenoxyacetamides (5a-k) were described in order to determine their in vitro antimicrobial activity against 3 Gram-positive, 3 Gram-negative bacteria and the fungus Candida albicans comparing with several control drugs. The derivative 5e was found active at a MIC value of 25 micrograms/ml against the whole tested Gram-positive bacteria strains and the Gram-negative microorganism Klebsiella pneumoniae. Moreover, the synthesized compounds 5a-k exhibited significant antibacterial activity against the enterobacter Pseudomonas aureginosae when compared to the control drugs. For the antifungal avtivity against C. albicans, the compound 5k was found more active than the other synthesized derivatives. On the other hand, the antimicrobial activity of some of these acetamide derivatives (5c, 5d, 5e, 5j and 5k) which are the possible metabolites of benzoxazoles, were also compared with their cyclic analogues 6-10. However, most of the MIC values of the benzoxazole derivatives provided better activity than the compared acetamides, while some others of the acetamide derivatives possessed either one fold improved (5d, 5e and 5j) or the same potency (5c, 5d, 5e, 5j and 5k) against the tested microorganisms.

Acetamides↗

Synthesis and antimicrobial activity of some new piperidinyl benzimidazoles.

A series of 2-(4-methylpiperidin-1-yl)-1,5(6)-disubstituted-1H-benzimidazoles (1-18) were prepared through the reaction of 2-chloro (or 2-chloromethyl)-1H-benzimidazole derivatives with 4-methylpiperidine. For the preparation of the individual isomers, compounds 7, 9 and 18 were synthesized by a multistep procedure. The prepared compounds were screened for their in vitro antibacterial and antifungal activities. Compound 3 and 4 exhibited the best antifungal activity.

Anti-Bacterial Agents↗

Adolescent health: a Middle East and North African perspective.

Adolescence is a period of physical, psychological and social transition from childhood to adulthood. At present there are 95 million young people aged between 10 and 24 years in the Middle East and North Africa. Female education is increasing in these regions, but secondary school enrollment rates for girls lag behind those of their male counterparts. Average age at first marriage varies between 17.9 and 24.3 years, but teenage marriage is quite common. Total fertility rates are higher than the world average. Pregnancy at an early age often translates into a high fertility rate and high risks for women and their children. Female children's share of food, health care, work options and general care is often less than that of boys, because they are perceived to be less valuable than boys in some countries.

Adolescent↗

The issue of sex selection in Turkey.

In accordance with a recent decision of the High Health Council, which is the highest advisory Council of the Ministry of Health, and following 6 months of debate, the clinical application of sex selection methods when there are no medical indications has been restricted in Turkey. The participants of the debate were the Turkish counterparts of Dr R.J. Ericsson, who is the owner of the patent of the sperm separation method, the General Directorate of Mother and Child Health and Family Planning, the Ethical Committee of the Turkish Medical Association, the Legal Consultancy of the Ministry of Health and the whole community through the press and television programmes. Many reports concerning sex selection were prepared that were opposed to the application of the Ericsson method when there were no medical indications, depending on ethical and technical considerations. The debate also induced ethical discussions about other related subjects, such as recent improvements in reproductive technologies, prenatal diagnosis and the Human Genome Project.

Bioethics↗