Tuberculosis of the parotid gland.
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Female↗
Biomedical subjects
Ahmet Koç
Publications and source records attributed to Ahmet Koç.
Otorhinolaryngological procedures in the fifteenth century in Anatolia.
The author of one of the earliest surgical books was Serefettin Sabuncuoğlu (AD 1385 to 1468?). He is the author of Cerrahiyyetül-Haniyye (Imperial Surgery), which was written in 1465. This book contains miniatures of surgical procedures, and there were many important and major new contributions to the surgical literature originally described by Sabuncuoğlu himself. He described surgical management of nasal polyposis, nasal fracture, facial palsy, mandibular fracture and dislocation, hoarseness and constriction of the breath, tumors of the tonsil and uvula, laryngeal tumors, and goiter. The aim of this report is to describe his contributions to otorhinolaryngology.
General Surgery↗
Temporal bone measurements on high-resolution computed tomography.
The distances between the important neural and vascular structures in normal temporal bones were measured by using high-resolution computed tomography (HRCT). We examined 100 normal ears in 50 subjects ranging in age from 15 to 72 years (mean age 39 years). We measured the distances from the medial lip of the posterior wall of the internal auditory canal to the medial wall of the vestibule (mean 9.7 mm), from the cochlea to the tympanic segment of the facial canal (mean 1.76 mm), from the medial wall of the vestibule to the lateral aspect of the lateral semicircular canal (mean 8.03 mm), and from the external auditory canal to the lateral sinus (mean 13.2 mm). HRCT examination is the best method for defining the morphology of temporal bone.
Adolescent↗
Hydroxyurea arrests DNA replication by a mechanism that preserves basal dNTP pools.
The relationship between dNTP levels and DNA synthesis was investigated using alpha factor-synchronized yeast treated with the ribonucleotide reductase inhibitor hydroxyurea (HU). Although HU blocked DNA synthesis and prevented the dNTP pool expansion that normally occurs at G1/S, it did not exhaust the levels of any of the four dNTPs, which dropped to about 80% of G1 levels. When dbf4 yeast that are ts for replication initiation were allowed to preaccumulate dNTPs at 37 degrees C before being released to 25 degrees C in the presence of HU, they synthesized 0.3 genome equivalents of DNA and then arrested as dNTPs approached sub-G1 levels. Accumulation of dNTPs at G1/S was not a prerequisite for replication initiation, since dbf4 cells incubated in HU at 25 degrees C were able to replicate when subsequently switched to 37 degrees C in the absence of HU. The replication arrest mechanism was not dependent on the Mec1/Rad53 pathway, since checkpoint-deficient rad53 cells also failed to exhaust basal dNTPs when incubated in HU. The persistence of basal dNTP levels in HU-arrested cells and partial bypass of the arrest in cells that had preaccumulated dNTPs suggest that cells have a mechanism for arresting DNA chain elongation when dNTP levels are not maintained above a critical threshold.
DNA Replication↗
Replication-independent MCB gene induction and deoxyribonucleotide accumulation at G1/S in Saccharomyces cerevisiae.
In Saccharomyces cerevisiae, many genes encoding enzymes involved in deoxyribonucleotide synthesis are expressed preferentially near the G1/S boundary of the cell cycle. The relationship between the induction of deoxyribonucleotide-synthesizing genes, deoxyribonucleoside triphosphate levels, and replication initiation was investigated using factor-synchronized wild-type yeast or dbf4 yeast that are temperature-sensitive for replication initiation. Neither the timing nor extent of gene induction was inhibited when factor-arrested dbf4 cells were released into medium containing the ribonucleotide reductase inhibitor hydroxyurea, which blocks replication fork progression, or were released at 37 degrees C, which blocks replication origin firing. Thus, the induction of deoxyribonucleotide-synthesizing genes at G1/S was fully independent of DNA chain elongation or initiation. Deoxyribonucleoside triphosphate levels increased severalfold at G1/S in wild-type cells and in dbf4 mutants incubated at the non-permissive temperature. Thus, deoxyribonucleoside triphosphate accumulation, like the induction of deoxyribonucleotide-synthesizing genes, was not dependent on replication initiation. Deoxyribonucleoside triphosphate accumulation at G1/S was suppressed in cells lacking Swi6, a transcription factor required for normal cell cycle regulation of deoxyribonucleotide-synthesizing genes. The results suggest that cells use gene induction at G1/S as a mechanism to pre-emptively, rather than reflexively, increase the synthesis of DNA precursors to meet the demand of the replication forks for deoxyribonucleotides.
Blotting, Northern↗
Evaluation of the mastoid air cell system by high resolution computed tomography: three-dimensional multiplanar volume rendering technique.
The mastoid air cell system is an important contributor to the pathophysiology of middle-ear inflammatory disease. The mastoid cavity is not only an air reservoir, but also an active space for gas exchange. Various methods of temporal bone imaging have been designed to investigate mastoid pneumatization. In this study, we examined 100 normal temporal bones for the evaluation of mastoid pneumatization. Mastoid air cell systems were measured by reconstructed axial and coronal high resolution computed tomography (HRCT) images. The reconstructions were made by a three-dimensional multiplanar volume rendering (3D MPVR) technique. The mean volume of the mastoid air cell pneumatization was 7.9 cm(3) (4.0-14.0 cm(3), SD = 2.3 cm(3)). The ears were allocated to the groups with respect to measured mastoid air cell pneumatization. Twenty-eight per cent of the ears have small pneumatization with an air cell system not exceeding 6 cm(3). Fifty-two per cent had an air cell system between six and 10 cm(3), and 20 per cent had an air cell system exceeding 10 cm(3). With its excellent imaging quality and the ability to eliminate bone and soft tissue, HRCT is the best method for evaluating the mastoid air cell system. The 3D MPVR technique must be used to measure the temporal bone/mastoid pneumatization for the best results.
Adolescent↗
Sudden sensorineural hearing loss: literature survey on recent studies.
Sudden sensorineural hearing loss (SSHL) is a symptom of cochlear injury. It is characterized by sudden onset, and, within a few hours, it reaches its maximum peak. It may be accompanied by vertigo and tinnitus. Many hypotheses have been advanced to explain its etiology: viral inflammation, vascular diseases, allergic reaction, rupture of intralabyrinthine membranes, and autoimmune diseases. The decrease in hearing may be unilateral or bilateral. To assess the histopathology of the labyrinth in cases of SSHL and to provide a better understanding of the etiopathogenesis, many studies have been carried out. Atrophy of the organ of Corti, loss of cochlear neurons, labyrinthine fibrosis, formation of new bone, and degeneration of the spiral ligament, vascular stria, hairy cells, dendrites, and apical spiral ganglion cells have been reported in temporal bone studies. In this article, new studies on the histopathologic and therapeutic bases of SSHL are reviewed.
Ear, Inner↗
Genetic predisposition for tympanosclerotic degeneration.
Atherosclerosis and tympanosclerosis are disorders that affect different organs in the body. When tissue samples taken from atherosclerotic and tympanosclerotic lesions are compared under light and electron microscopes, common pathological characteristics become apparent in both tissues. These similarities indicate that genetic predisposition to atherosclerosis is also seen in the middle ear. For the purpose of evaluating this genetic predisposition, the incidence of tympanosclerosis in atherosclerotic patients was examined and compared with the normal population. Otoscopic examination of 1,024 atherosclerotic patients was performed, and myringosclerosis was revealed in 66.6%. Myringosclerosis was found in 36 out of 300 non-atherosclerotic patients (12%). In the group of atherosclerotic patients, 174 individuals had past histories of previous ear infections. Myringosclerosis was detected in 147 of these patients (84.5%) during ear examinations. In 637 non-atherosclerotic patients with histories of ear infections, this figure was 114 (17.7%). The high rate of tympanosclerosis observed in atherosclerotic patients in comparison to the normal population was found to be statistically significant. These findings indicate that there must be a genetic predisposition for sclerotic degeneration in some individuals.
Adult↗
Autoimmune hemolytic anemia preceding T-ALL in a five-year-old girl.
A 5-year-old girl developed acute lymphoblastic leukemia (T-ALL) 15 months after being diagnosed with autoimmune hemolytic anemia (AHA), while AHA was in partial remission. AHA was mediated by warm antibodies. Because AHA could not be controlled during the induction therapy of ALL, she was administered immunoglobulin G and plasmapheresis was performed. Hepatomegaly dissappeared in the 4th month. However, anemia requiring blood transfusion, positive direct Coombs' test, and splenomegaly dissappeared in the 13th month of the leukemia treatment; reticulocytosis and decreased haptoglobin level persisted. AHA exacerbated in the 24th month of the ALL therapy. Prednisolone was started but the family refused to continue the therapy. This case presents some features that were not reported before, such that ALL was preceded by AHA and involved T-cell lineage, AHA was mediated by warm antibodies, and the two disorders took place in childhood.
Anemia, Hemolytic, Autoimmune↗