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Biomedical subjects

S Kaya

Publications and source records attributed to S Kaya.

At least 37 records · Page 2Linked to original sources
PubMed2001

Positive surgical margins in cancer of the larynx.

In order to determine what should be done for laryngeal cancer patients when surgical margins are positive, and to evaluate their prognosis, a retrospective review of 21 laryngeal cancer patients with positive surgical margins out of 714 surgically treated cases (2.9%) was carried out. Nineteen patients were treated with postoperative radiation therapy. Two patients who had had endolaryngeal partial laryngectomy were treated with vertical partial laryngectomy. Two patients were lost to follow-up. Ten patients (10/19; 53%) were recurrence-free. Four patients had local, two had regional, and two had locoregional recurrences. Only one patient with a local recurrence could be salvaged with total laryngectomy and is disease-free. One patient developed liver metastasis. Nineteen patients had a mean and median disease-free survival of 48 and 36 months, respectively. Nine out of fourteen patients (64%) treated curatively were recurrence-free. The patients with positive margins developed significantly more locoregional recurrences than those with free margins (P < 0.05). We conclude that surgical margins must be checked peroperatively with frozen sections to make sure that they are free. The margins of every laryngectomy specimen must be diligently examined. If positive, re-excision, postoperative radiotherapy and chemotherapy are treatment alternatives. They should not just be managed with close follow-up. However, whatever treatment is applied, the prognosis for patients with positive margins is significantly worse than for those with free margins.

Adult↗
PubMed2001

Factors affecting appropriateness of hospital utilization in two hospitals in Turkey.

To determine the extent of inappropriate hospital use, to investigate factors related to variations in appropriateness, and to identify reasons for inappropriateness, the Appropriateness Evaluation Protocol (AEP) was applied to 2,067 patient days in two hospitals between March 1997 and 1998 in Ankara, Turkey. A substantial amount of inappropriate utilization was found in both hospitals (34.2%, 24.6%). Factors affecting the appropriateness of hospital utilization and reasons for inappropriateness were varied and presented by internal medicine, general surgery, and gynecology services. In general, results of the logistic regression analysis indicated that inappropriateness was significantly associated with admission number (first admission/readmission), admission route (emergent/non-emergent), and day of the week. The most common reason for inappropriateness was diagnostic procedures and/or treatments that could have been carried out on an ambulatory basis. This study demonstrates that the AEP can be used as a tool to improve the efficiency of the Turkish hospitals.

Cross-Sectional Studies↗
PubMed2001

Effects of zinc and vitamin A supplements on plasma levels of thyroid hormones, cholesterol, glucose and egg yolk cholesterol of laying hens.

The effects of zinc and vitamin A supplementation to the diet on some blood metabolites were evaluated in Hisex brown laying hens from 56 weeks to 68 weeks of age. A total of 130 birds were divided into two main groups according to vitamin A treatment (0 and 3.44 mg retinyl acetate kg(-1) feed, respectively), each consisting of 65 hens. Hens in both of the main groups were then divided into five zinc treatment groups (0, 25, 50, 100 and 200 mg zinc kg diet(-1) respectively) of 13 hens each. It was observed that plasma T4, T3 and total cholesterol levels were affected by only zinc supplementation. While 100 and 200 mg Zn kg(-1) decreased plasma T4 level compared to control value, plasma T3 level was reduced by 100 mg Zn kg(-1) compared to groups fed less Zn. Adding 50 and 200 mg Zn kg(-1) to the diet increased plasma total cholesterol level in the birds compared to other groups. Vitamin A, zinc, and their interaction did not influence the concentration of plasma high-density lipoprotein (HDL)-cholesterol, glucose and egg yolk cholesterol in laying hens.

Animals↗
PubMed2001

The oligomeric nature of Na/K-transport ATPase.

Since the discovery of Na/K-ATPase, evidence has accumulated to suggest that 1 mol of ATP hydrolysis occurs via the Na(+)-occluded ADP-sensitive phosphoenzyme, the K(+)-sensitive phosphoenzyme and the K(+)-occluded enzyme accompanying active transport of 3Na(+) and 2K(+) according the Post-Albers scheme. However, some controversial issues have arisen concerning whether the functional unit of the enzyme is an alpha beta-protomer or a much higher oligomer, which would be related to the mechanism of transport, either sequential or simultaneous. Detailed studies of oligomer interaction and the reactivity of the enzyme and a comparison of the extent of phosphorylation with ligand-binding capacities in the presence or absence of ATP hydrolysis and others strongly suggest that the functional unit of the enzyme in the membrane is a tetraprotomer, (alpha beta)(4). They also suggest that each reaction intermediate of the Post-Albers scheme, respectively, reflects half of the site property of the intermediate and that another half binds ATP. These data may be useful not only to answer the long-standing question of whether the mechanism functions in the presence of both Na(+) and K(+) but also contribute to a better understanding of the mechanism of P-type pump ATPase in general.

Adenosine Triphosphate↗
PubMed2001

Benign paroxysmal positional vertigo after stapedectomy.

OBJECTIVE: To determine the incidence of benign paroxysmal positional vertigo (BPPV) following stapedectomy in a patient group and the efficacy of the Epley maneuver in this group. STUDY DESIGN: Prospective study in a university-based tertiary referral system. METHODS: The patient group comprised 63 patients who had undergone stapedectomy; a control group consisted of normal healthy individuals with no otolaryngological complaints. All individuals underwent the Dix-Hallpike maneuver for the diagnosis of BPPV. Patients who exhibited vertigo, torsional nystagmus (which reverses its direction on return to sitting position) preceded by a latent period, and the fatigability of these findings were considered to have BPPV. If the test result was positive, they underwent the Epley therapeutic maneuver. RESULTS: Four of the patients who had undergone a stapedectomy showed characteristic findings of BPPV. No individual in the control group had BPPV. All patients responded well to the Epley maneuver. CONCLUSIONS: Stapedectomy may be regarded as an etiological factor in BPPV. Because the fenestra is located in the posterior part of the stapes footplate, the pathophysiology appears to be related to utricular rather than saccular trauma. Correct measurement of the distance between the incus and stapes footplate is essential in stapedectomy. An Internet survey of the relevant literature in English shows a scarcity of publications on the incidence of BPPV following stapedectomy. In the present study, 63 patients who had undergone a stapedectomy were investigated for the presence of BPPV; all had Dix-Hallpike maneuvers performed for the diagnosis. Sixty-three individuals with no otolaryngological complaints made up the control group. Four of the patients who had undergone stapedectomy showed characteristic findings of BPPV, and no individual in the control group had BPPV; the difference between the two groups was statistically significant. All four of the patients diagnosed with BPPV responded well to the Epley maneuver. The pathophysiology appears to be related to utricular trauma. Correct measurement of the distance between the incus and stapes footplate is essential in stapedectomy.

Adult↗
PubMed2001

Lung perfusion in hemorrhagic shock of rats: the effects of resuscitation with whole blood, saline or Hes 6%.

This study was undertaken to determine the effects of various resuscitation regimens on lung perfusion following resuscitation from hemorrhagic shock. Fourty male Sprague-Dawley rats (250-300 g) were used. The rats were divided randomly into four groups (n = 10 for each) and were sedated with intramuscular ketamine (100 mg/kg). We measured blood pressure, rectal temperature and lung perfusion using radioscintigraphy with a technetium colloid indicator. The systolic blood pressure was decreased 75% by removing blood via v. jugularis in the first three groups and group 4 was accepted as the control group, and blood volume was not diminished. Then the first three groups were resuscitated with autologous blood containing 125 units heparine/ml in group 1, saline in group 2, and hydroxyethyl starch (HES) 6% in group 3. After the correction of hypovolemia, all animals were injected 100 Bg (0.1 cc) technetium 99 m macroaggregated albumin (99mTc MAA) via penil vein. After injection of 99mTc MAA, 3 minutes fixed images were detected by a y camera in posterior position at 15 minutes and 5 hours. 99mTc MAA "wash out" rate in lung was determined quantitatively at 5 hours. Compared to a control group, lung perfusion was decreased significantly in groups resuscitated with saline, and HES 6% while perfusion was restored with autologous blood. We conclude that heparinized autologous blood saved lung capillary circulation in hemorrhagic shock in rats.

Albumins↗
PubMed2001

Pharmacokinetics of enrofloxacin after intravenous and intramuscular administration in Angora goats.

Pharmacokinetics and bioavailability of enrofloxacin were determined after single intravenous (IV) and intramuscular (IM) administrations of 5 mg/kg body weight (BW) to 5 healthy adult Angora goats. Plasma enrofloxacin concentrations were measured by high performance liquid chromatography. Pharmacokinetics were best described by a 2-compartment open model. The elimination half-life and volume of distribution after IV and IM administrations were similar (t1/2beta, 4.0 to 4.7 h and Vd(ss),1.2 to 1.5 L/kg, respectively). Enrofloxacin was rapidly (t1/2a, 0.25 h) and almost completely absorbed (F, 90%) after IM administration. Mean plasma concentrations of enrofloxacin at 24 h after IV and IM administration (0.07 and 0.09 microg/mL, respectively) were higher than the minimal inhibitory concentration (MIC) values for most pathogens. In conclusion, once-daily IV and IM administration of enrofloxacin (5 mg/kg BW) in Angora goats may be useful in treatment of infectious diseases caused by sensitive pathogens.

Animals↗
PubMed2000

Melanotic neuroectodermal tumor of infancy: report of two cases and review of literature.

Melanotic neuroectodermal tumor of infancy (MNTI) is a rare, distinctive neoplasm containing melanin; it primarily affects the maxilla of the infants during the first year of life. Approximately 150 instances of this tumor are reported in the medical literature. Genesis of the tumor is obscure and the diagnosis is challenging for the pathologist. Two cases operated by the first author are presented, and the diagnostic features and treatment alternatives of MNTI discussed.

Biopsy, Needle↗
PubMed2000

Comparison of regional recurrence rates of radical and comprehensive neck dissection type 3 in N0 laryngeal cancer.

To determine whether comprehensive neck dissection (CND) type 3 could accomplish regional tumor control as well as radical neck dissection (RND) in clinically N0 laryngeal cancer patients, we compared the regional recurrence rates of 316 N0 laryngeal cancer patients. In the 316 N0 patients, 486 neck dissections were performed. For 170 patients the dissection was bilateral, and for 146 patients it was unilateral. Of these, 193 were type 3 CNDs, and 293 were RNDs. In 30 (15.5%) of 193 type 3 CNDs and in 53 (18.1%) of 293 RNDs, metastatic lymph nodes were determined histopathologically in neck dissection specimens. The difference in cervical lymph node metastasis rates was not statistically significant (P > 0.05). During follow-up, 3 patients who underwent CND type 3 (1.6%) and 12 who underwent RND (4.1%) had regional recurrences. The difference between recurrence rates was not statistically significant (P > 0. 05). A conclusion was reached that CND type 3 safely provided regional cancer control in N0 laryngeal cancer and that it might be performed to decrease the morbidity of RND.

Humans↗
PubMed2000

Liability and validity of the Appropriateness Evaluation Protocol in Turkey.

OBJECTIVE: To assess the inter-rater reliability between nurses and the convergent validity of the Appropriateness Evaluation Protocol (AEP) in the Turkish context. METHODS: Two nurses applied the original AEP concurrently to a random subsample of 335 patient-days in internal medicine, general surgery, and gynaecology departments at a university hospital and a government teaching hospital, as a part of a larger study. Inter-rater reliability was tested by calculating overall agreement and specific agreements between nurse reviewers' AEP assessments. Validity was tested by comparing the assessments of the nurses based on the AEP with the implicit judgements of five expert physicians on a random subsample of 818 patient-days. Sensitivity, specificity, positive and negative predictive values of the AEP were calculated. Reliability and validity were also evaluated by the K statistic. RESULTS: In the reliability test, there was a high level of agreement between the two independent raters applying the AEP in the three departments studied: overall agreement = 90.7-97.6%; specific inappropriate agreement = 69.1-92.3%; specific appropriate agreement = 88.3-96.6%. In validity testing, the AEP had a sensitivity of 0.83-0.97, specificity of 0.62-0.80, and positive and negative predictive values of 0.84-0.88 and 0.73-0.95 respectively. Kappa coefficients in internal medicine and gynaecology indicated almost perfect agreement in reliability testing and moderate agreement in validity testing. In general surgery, the K coefficients showed substantial agreement in both tests. CONCLUSION: These results indicate that the AEP is a reliable and valid instrument to assess appropriateness of patient-days in Turkey.

Hospital Departments↗
PubMed2000

Membrane enzyme systems responsible for the Ca(2+)-dependent phosphorylation of Ser(27), the independent phosphorylation of Tyr(10) and Tyr(7), and the dephosphorylation of these phosphorylated residues in the alpha-chain of H/K-ATPase.

H/K-ATPase preparations (the G1 membrane) from pig stomach contain both kinases and phosphatases and show reversible phosphorylation of Tyr(7), Tyr(10), and Ser(27) residues of the alpha-chain of H/K-ATPase. The Tyr-kinase is sensitive to genistein and quercetin and recognized by anti-c-Src antibody. The Ser-kinase is dependent on Ca(2)(+) (K(0.5) = 0.9 microM), sensitive to a PKC inhibitor, and recognized by antibodies against PKCalpha and PKCbetaII. The addition of 3-[(3-cholamidopropyl)dimethylammonio]-1-propane-sulfonic acid (CHAPS) caused a dramatic increase in the phosphorylation of added synthetic copolymer substrates and permitted the phosphorylation of maltose-binding proteins fused with the N-terminal domain of alpha-chains. The phosphotyrosine phosphatase was inhibited by vanadate. The phosphoserine phosphatase was inhibited by okadaic acid and by inhibitor-2. The presence of protein phosphatase-1 was immunologically detected. Column chromatographic separation of CHAPS-solubilized G1 membrane and others indicate the apparent molecular weight of the Src-kinase to be approximately 60 kDa, the PKCalpha and/or PKCbII to be approximately 80 kDa, the Tyr-phosphatase to be 200 kDa, and PP-1 to be approximately 35 kDa. These data show that these membrane-bound enzyme systems are in sufficiently close proximity to be responsible for reversible phosphorylation of Tyr(7), Tyr(10), and Ser(27) of the catalytic subunit of membrane H/K-ATPase in parietal cells, the physiological role of which is unknown.

Animals↗
PubMed2000

Transmaxillary excision of a rare cavernous hemangioma of the infratemporal fossa.

Cavernous hemangiomas that manifest as a primary tumor of the infratemporal fossa are exceedingly rare. We report such a case in a 40-year-old woman. Her lesion was excised via a transantral anterior approach. Although this approach is usually recommended only for biopsy, in selected cases it can be used to excise a lesion without causing any significant complications. We recommend the transantral anterior approach for relatively small, benign lesions that show no evidence of invasion into surrounding tissues because it does not expose the patient to surgical complications such as transient or permanent facial nerve injury or cosmetic deformity.

Adult↗
PubMed1999

Acid-labile ATP and/or ADP/P(i) binding to the tetraprotomeric form of Na/K-ATPase accompanying catalytic phosphorylation-dephosphorylation cycle.

The Na/K-ATPase has been shown to bind 1 and 0.5 mol of (32)P/mol of alpha-chain in the presence [gamma-(32)P]ATP and [alpha-(32)P]ATP, respectively, accompanied by a maximum accumulation of 0.5 mol of ADP-sensitive phosphoenzyme (NaE1P) and potassium-sensitive phosphoenzyme (E2P). The former accumulation was followed by the slow constant liberation of P(i), but the latter was accompanied with a rapid approximately 0.25 mol of acid-labile P(i) burst. The rubidium (potassium congener)-occluded enzyme (approximately 1.7 mol of rubidium/mol of alpha-chain) completely lost rubidium on the addition of sodium + magnesium. Further addition of approximately 100 microM [gamma-(32)P]ATP and [alpha-(32)P]ATP, both induced 0.5 mol of (32)P-ATP binding to the enzyme and caused accumulation of approximately 1 mol of rubidium/mol of alpha-chain, accompanied by a rapid approximately 0.5 mol of P(i) burst with no detectable phosphoenzyme under steady state conditions. Electron microscopy of rotary-shadowed soluble and membrane-bound Na/K-ATPases and an antibody-Na/K-ATPase complex, indicated the presence of tetraprotomeric structures (alphabeta)(4). These and other data suggest that Na/K-ATP hydrolysis occurs via four parallel paths, the sequential appearance of (NaE1P:E.ATP)(2), (E2P:E.ATP:E2P:E. ADP/P(i)), and (KE2:E.ADP/P(i))(2), each of which has been previously referred to as NaE1P, E2P, and KE2, respectively.

Adenosine Diphosphate↗
PubMed1999

Prognostic significance of histopathological parameters in cancer of the larynx.

In this study we investigated the prognostic significance of differentiation, the mode of tumor invasion to surrounding tissues, the microscopic appearance of tumor, peritumoral lymphocytic infiltration and cartilage involvement according to disease-free survival, and the recurrence and presence of cervical lymph node metastasis in cancer of the larynx. Only the mode of tumor invasion to surrounding tissues was significantly related to survival (P < 0.05). The patients with "well-defined margin" tumors survive significantly longer than those with "groups of cells, no distinct margin." Patients with supraglottic tumors and a mode of invasion other than "well-defined margin" have a significantly higher risk of recurrence (P < 0.05) and therefore require adjuvant therapy. Patients with poorly differentiated, cartilage invading, ulcerative supraglottic tumors, and patients with glottic tumors having diffusely infiltrating margins, certainly need elective neck dissection (P < 0.05). According to the multivariant analysis, none of the factors significantly affect disease-free survival independently (P > 0.15). According to multiple logistic regression and cox regression analysis, in decreasing order of significance, the mode of invasion, microscopic tumor appearance and lymphocytic infiltration significantly affect the recurrence and time between surgery and the development of recurrence independently (P < 0.15).

Adult↗
PubMed1999

Direct evidence for in vivo reversible tyrosine phosphorylation of the N-terminal domain of the H/K-ATPase alpha-subunit in mammalian stomach cells.

In vivo reversible phosphorylation of Tyr-7 and Tyr-10 of the pig stomach H/K-ATPase alpha-chain was initially demonstrated in mammals, rat, rabbit, and pig, in the presence of vanadate + H(2)O(2). In vitro phosphorylation has also been unequivocally demonstrated via the use of protease inhibitors during membrane H/K-ATPase preparation. An amphoretic detergent permitted each intrinsic kinase to phosphorylate each fusion protein containing the requisite Tyr residues, along with a reduction in alpha-chain phosphorylation. These and other data suggest that some important enzyme systems are present in the apical membrane and that they are in sufficient proximity to participate in the reversible phosphorylation of the amino terminal soluble domain of the alpha-chain with an unknown physiological function in the membrane embedded H/K-ATPase.

Animals↗
PubMed1999

[Tetraprotomeric hypothesis of Na/K-ATPase].

Since the discovery of Na/K-ATPase by Skou, the mechanism of Na/K-dependent ATP hydrolysis and Na and K transport has been extensively studied. The hydrolysis appears to occur sequentially via the Na-Enzyme-ATP complex (NaE1ATP), ADP-sensitive phosphoenzyme (NaE1P), the K-sensitive phosphoenzyme (E2P) and the K-occluded enzyme (KE2), known the Post-Albers mechanism, in a protomer or diprotomer that consists of alpha- and beta-chains. The tetrameric nature of the enzyme such as a quarter, half, third to fourth and full site reactivity and the visualization by electron microscopy show direct biochemical evidence for the presence of a tetraprotomer structure of Na/K-ATPase during ATP hydrolysis. ATP binding is followed by two parallel paths, which occur at each of the two half sites for phosphorylation-dephosphorylation, and direct ATP hydrolysis via (NaE1P : E.ATP)2, (E2P : E.ATP : E2P : E.ADP/Pi) and (KE2 : E.ADP/Pi)2, respectively. The sequential formation of E2P from NaE1P and KE2 from E2P is accompanied by, respectively, hydrolysis of half of the TCA-labile bound ATP to ADP/Pi and of another half of the bound ATP to ADP/Pi. All reaction intermediates detectable in the Post-Albers scheme bind ATP and/or ADP/Pi.

Adenosine Diphosphate↗