Biomedical subjects
Publications and source records attributed to S Marinković.
Tertiary amines can be added to electron-deficient alkenes with yields up to 98% in a radical chain reaction initiated by a photochemical electron transfer using inorganic semiconductors like TiO2 as sensitiser.
BACKGROUND: The available information about certain microanatomic features of the AChA perforators is incomplete. Precise knowledge of these vessels is necessary to understand the consequences of their occlusion and to safely operate in their region. METHODS: The AChA perforators were microdissected and examined under the stereoscopic microscope in 10 vascular casts and in 20 hemispheres injected with india ink or radiopaque substance. RESULTS: The perforating branches ranged in number from 2 to 9 (mean, 4.6) and in diameter between 90 microm and 600 microm (mean, 317 microm). The most proximal perforator arose 3.2 mm on average caudal to the AChA origin. The most distal (capsulothalamic) perforator varied in size from 200 microm to 610 microm (mean, 431 microm). One or more of the perforators always originated from the AChA (100%), but some of them also from the uncal (33.3%) or parahippocampal branch (10%) of the AChA, either as individual vessels only (70%) or from common trunks (30%). The perforators gave off the peduncular (20%), optic (23.3%), or uncal side branches (26.7%). CONCLUSIONS: Our findings concerning the origin, position, number, size, branching, penetration site, and relationships of the AChA perforators gave the anatomic basis for safe operations in patients with AChA aneurysms or mediobasal limbic epilepsy.
BACKGROUND: While the characteristics of the vasculature of the second (intracanalicular) segment of the hypoglossal nerve are well known, the vascularization of the first (cisternal) segment of this nerve has not been examined so far. Many pathologic processes and malformations can be located in the premedullary cistern, which may affect the vasculature of the cisternal segment. Consequently, we decided to examine the blood supply of the cisternal segment. METHODS: The anatomic features of the cisternal segment and its vasculature were examined in 15 hypoglossal nerves after injection of india ink and gelatin into the vertebrobasilar arterial system. RESULTS: The cisternal segment was noted to consist of 3-15 long roots, which usually formed two trunks of the hypoglossal nerve. The roots of each nerve received blood from the anterolateral and the lateral medullary arteries, which ranged from 3 to 5 in number and between 100 microns and 500 microns in caliber. These arteries may arise from the perforating branches or the pontomedullary branch of the basilar artery; the vertebral artery or its perforators; the anterior spinal artery or its vascular roots; the posterior spinal artery; and the posterior inferior cerebellar artery. The main hypoglossal arteries, which ranged in diameter from 20 microns to 80 microns, always coursed along the dorsal surface of the roots of the hypoglossal nerve. CONCLUSIONS: The cisternal segment of the hypoglossal nerve was always vascularized by several vessels, which mainly originated from the vertebral artery and its branches. This observation was discussed from the neurosurgical point of view.
We examined in detail the cisternal segments of 15 trochlear nerves in brain stems injected with India ink and fixed in formalin. The nerves were found to emerge as singular trunks (33.3%), singular trunks with accessory rootlets (13.3%), or two or three roots with (26.7%) or without accessory rootlets (26.7%). The nerves were in close relationship or in contact with the superior cerebellar artery, that is, with the main trunk of the superior cerebellar artery, its medial and lateral terminal stems, the accessory superior cerebellar artery, and the vermian, paravermian, collicular, and lateral hemispheric arteries as well as their small branches. Some of these vessels were connected by anastomoses in 86.7% of the cases. The anastomotic channels varied from 40 to 530 microns in diameter. The cisternal segment of each trochlear nerve was usually supplied by a single long artery, which most often arose from the vermian artery (26.7%) or the collicular artery (26.7%). The feeding vessel ranged from 30 to 80 microns in caliber. We discuss the possible clinical significance of the anatomic data observed in the present study.
OBJECTIVE: Despite detailed studies of the perforating arteries, their relationships with the leptomeningeal arteries are almost unknown. These relationships can be of great significance during neurosurgical operations. METHODS: The arteries of the hemispheres, which ranged in number from 17 to 36, were injected with india ink or methylmethacrylate. RESULTS: The perforating vessels were noted to arise from the following leptomeningeal arteries: the subcallosal branch of the anterior communicating artery (26.6%); the median artery of the corpus callosum (6.6%); the medial orbitofrontal (6.6%) and the olfactory branch (3.3%) of the anterior cerebral artery; the accessory middle cerebral artery (3.3%); the frontal and temporal branches of the middle cerebral artery (66.6%); the temporal branches of the internal carotid and the anterior choroidal arteries (25% each); the peduncular branch of the posterior communicating artery (4.8%); the peduncular, collicular and medial posterior choroidal branches of the posterior cerebral artery (40%); the cerebellar branches (100%); the long pontine branches (20-26.6%); the anterolateral branches (33.3%) of the basilar artery; and the anterolateral or the lateral medullary branches (35.3%) of the vertebral artery. From 19.4 to 100% of some leptomeningeal vessels originated in the large perforating arteries. CONCLUSION: From 4.8 to 100% of certain groups of the perforating vessels originated in the leptomeningeal arteries. Occlusion of a leptomeningeal artery that gives rise to the perforating vessel(s) may lead to superficial and deep infarcts in the same patient.
The trigeminocerebellar artery was found on the left side in one of 22 brainstems, with the vasculature injected with India ink or methylmethacrylate. The trigeminocerebellar artery, which measured 910 microns in diameter, arose from the basilar artery. The artery was divided into the pontine, trigeminal, cerebellopontine, and cerebellar segments. The artery supplied the anterolateral and lateral part of the pons, the trigeminal nerve root, the middle cerebellar peduncle, and most of the petrosal surface of the cerebellar hemisphere. Although relatively rare, the trigeminocerebellar artery may cause trigeminal neuralgia. Occlusion of this artery would cause a syndrome similar to the lateral midpontine syndrome. The trigeminocerebellar artery could be misinterpreted on angiograms as the anterior inferior cerebellar artery with a high origin from the basilar artery.
BACKGROUND: Very little can be found in the literature concerning the variation of the irrigation area of the cerebellar arteries, as well as the characteristics of anastomoses among these vessels. The anatomical features may determine certain features of cerebellar infarcts. Consequently, we examined the irrigation area of and the anastomoses among the cerebellar arteries. METHODS: The anatomical features of the posterior inferior cerebellar artery (PICA), the anterior inferior cerebellar artery (AICA), and the superior cerebellar artery (SCA) were studied in 26 cerebella injected with india ink, while their irrigation areas and anastomoses were examined in 8 of these cerebella. RESULTS: The PICA, which most often (82%) arose from the vertebral artery, was found most commonly (81.3%) to supply the largest part of the occipital surface of the cerebellar hemisphere, the caudal or caudomedial part of the tentorial surface, and the inferior vermis. The AICA, which usually (92%) arose from the basilar artery, commonly (68.8%) supplied most of the petrosal surface of the hemisphere and the flocculus. The SCA, which divided into the medial and the lateral trunks, always irrigated most of the tentorial surface of the cerebellum, the superior vermis, and the dentate nucleus. The PICA, AICA, and SCA were always interconnected by anastomoses, which ranged from 40 microns to 420 microns in diameter. CONCLUSIONS: Cerebellar infarcts were documented by computed tomography (CT) or magnetic resonance imaging (MRI) examinations in 10 patients. The infarcts were located in the PICA territory (60%) or the SCA region (40%). The authors compared the obtained anatomic data to the features of the cerebellar infarcts in these patients.
In the field of developmental paratesticular anomalies there are numerous questions without answers. The goal of this paper is to give some information on embryology of normal and disturbed development parallely, as well as to describe the occurrence of certain anomalies with a special review on anomalies of epididymis and deferent ductus considering their importance in urology. Results and statistical data from our work have been reported.
The 27 oculomotor nerves were examined after injection of India ink or methylmethacrylate into the vertebral and the internal carotid arteries. The ventral surface of the cisternal segment of the nerve was noted to be in close relationship with the superior cerebellar artery (96.3%) and its pontine (37.0%), mesencephalic (25.9%) and perforating branches (81.5%); the posterolateral pontine artery (70.4%) and its branches; the anterolateral pontine branches (29.6%), and the perforating branches (85.2%) of the basilar artery; the mesencephalic perforating arteries (11.1%) and their peduncular branches (62.9%); the peduncular branches of the diencephalic perforators (11.1%) and the P1 segment (18.5%); and the accessory collicular artery (3.7%). The dorsal surface of the nerve was in close relationships to the P1 and P2A segments (100%) of the posterior cerebral artery and their peduncular branches (22.2%); the posterior communicating artery (100%); the collicular (100%) and the accessory collicular artery (33.3%), and their peduncular (51.8%) or the perforating branches (22.2%); the medial posterior choroidal artery (25.9%) and its branches (11.1%); and the mesencephalic and diencephalic perforating arteries (100%). Vascular penetration was noted in 51.8% of the third nerves. The most common penetrating vessel was the collicular artery (18.5%) and its branches (22.2%). The cisternal segment of the oculomotor nerve was most often supplied by the mesencephalic perforators (88.9%). The authors discuss the possible clinical significance of the obtained anatomic data.
A huge uncal branch of the anterior choroidal artery was found in one of 22 cerebral hemispheres. The uncal artery measured 0.7 mm in diameter. It gave off small branches to the uncus, as well as a large parahippocampal artery, the accessory anterior temporal artery, and the anterior hippocampal artery. This uncal artery supplied, in addition to the uncus, most of the ventromedial surface of the parahippocampal gyrus, part of its dorsal surface, the rostromedial portion of the lateral occipitotemporal gyrus, and the rostral part of the hippocampal formation. Such a huge uncal artery has implications for surgery in the uncohippocampal region.
An RNA-directed RNA polymerase (RdRP, EC 2.7.7.48) from tomato leaf tissue was purified to electrophoretic homogeneity. A terminal transferase activity that was found to cofractionate with RdRP from DEAE-Sepharose and DNA-cellulose columns was removed by chromatography on a Mono Q column. The highly purified RdRP exhibits a specific activity of 500 nmol x mg-1 x 30 min-1, which corresponds to a 100,000-fold enrichment of the enzyme. In buffer containing 50% glycerol, its activity decreased by about 15%/month. RdRP activity coincided with the silver staining intensity of a single 128-kDa polypeptide when the fractions eluted from the Mono Q column were analyzed by electrophoresis in a SDS-polyacrylamide gel. Its molecular mass and its sedimentation coefficient of 6.6 S indicate that RdRP is a nearly globular molecule. The catalytic activity of RdRP is resistant to alpha-amanitin and actinomycin D. In tomato leaves systemically infected with potato spindle tuber viroid, the activity of RdRP was found to be increased about 3-fold compared with RdRP isolated from healthy leaf tissue.
The catalytic properties of electrophoretically homogeneous RNA-directed RNA polymerase (RdRP, EC 2.7.7.48) from tomato leaf tissue were studied with the aid of oligonucleotides of defined sequence. It was found that RdRP catalyzes in vitro the transcription of short single-stranded RNA and DNA molecules into precisely complementary RNA copies up to the full length of these templates. The transcription of RNA- and DNA-oligonucleotide templates was equally effective. Differences in transcription efficiency were found to depend on nucleotide sequence rather than on the RNA or DNA nature of the single-stranded nucleic acid. Double-stranded nucleic acids such as poly(A).poly(U) and a double-stranded DNA 14-mer were not transcribed. The RdRP-directed transcription could be primed because RNA and DNA dinucleotides and trinucleotides complementary to the 3'-terminal nucleotides of the template were extended by the enzyme. The unprimed transcription was shown to start preferentially at the 3'-terminal nucleotides of the template. RdRP is capable of adding a single noncomplementary nucleotide to the 3' terminus of about 50% of the runoff transcripts. AMP was preferred over GMP, whereas CMP and UMP were terminally added at very low frequency.
Specific physiological features of the child's organism necessitate a preoperative assessment of hydromineral and acidobasic status and its correction in order to reduce intraoperative complications and accelerate postoperative recovery. The analysis was carried out in children who were operated on in general anesthesia in the period of one year. Their hydromineral and acidobasic status was assessed. On the basis of the clinical picture and laboratory analyses we assessed the dehydration and metabolical changes and made the corrections preoperatively. Given are tables for the compensation of basic physiological liquid and electrolyte quantities, a guide for the assessment and the correction of the dehydration levels and the correction of metabolical changes. We also gave tables for the compensation of liquid during the operation in general anesthesia. In the conclusion we review basic principles in the preparation for an urgent operation in general anesthesia in relation to hydromineral and acidobasic status as well as the administration of liquid during the operation.
In a two-year study on 24 newborn infants, diagnosis of hypertrophic pyloric stenosis (HPS) was intraoperatively confirmed, following preoperative ultrasonography. By means of real time sonography three parameters of the pyloric muscle were measured; the mean length was 19.6 mm, diameter 13.4 mm and the muscle thickness was 5.1 mm.
For a long period of time propofol has been in use for total intravenous anesthesia in adults. In our literature there are no data on the use of propofol in pediatric anesthesia. The aim of the study was to compare effects of propofol for the induction of anesthesia, maintenance and recovery after anesthesia, with barbiturate, that is, inhalation anesthesia during spontaneous breathing. 50 children underwent propofol anesthesia. A control group comprised 50 children who underwent thiopentone and halothane anesthesia. The average propofol dose was 2.38 mg/kg/tt. Monitoring of cardiovascular parameters revealed statistically significant variations in systolic and diastolic pressure in both groups, but a more significant decrease was recorded in the propofol group. The decrease, recorded only during the initiation of anesthesia, stabilized afterwards. Side effects (pain during the initiation, apnea, spontaneous movements) were present in the propofol anesthesia, while in the halothane group they were reduced. In the propofol group period of recovery was short, indicating advantages of this anesthetic in day care centers.
The hippocampal vessels were examined in 25 forebrain hemispheres injected with india ink or methylmethacrylate. There were two to seven hippocampal arteries, which measured 200-800 microns in diameter. The anterior hippocampal artery (AHA), which was present in 88.2% of the hemispheres, most often originated from the posterior cerebral and the anterior temporal arteries, that is, within the rostral hippocampo-parahippocampal arterial complex. It arose from the anterior choroidal artery in 29.4% of the hemispheres. The AHA extended between the uncus and the parahippocampal gyrus, and it supplied the head of the hippocampus. The middle hippocampal artery was constant. It most often arose from the posterior cerebral and the common temporal arteries. The middle hippocampal artery coursed just caudal to the uncus, in close relationship with the lateral posterior choroidal artery, and it usually supplied the middle part of the hippocampal formation. The posterior hippocampal artery, which existed in 94.1% of the hemispheres, most often arose from the posterior cerebral and the splenial arteries. It irrigated the caudal part of the hippocampal formation. The anastomoses connecting the posterior, middle, and the anterior hippocampal arteries were present in 29.4% of the hemispheres. The hippocampal arteries gave rise to the straight vessels, which divided into the large and the small intrahippocampal arteries. The highest density of the capillary network was noted in the pyramidal and molecular layers of the hippocampal formation. The clinical significance of the obtained microanatomical findings is discussed.
The anterior communicating artery (ACoA) and its branches were examined in 22 human brains after injecting Indian ink or methylmethacrylate. The ACoA branches were divided into the small and the large. Small branches were from 1 to 5 in number (mean 2), and from 70 to 270 microns in diameter (mean 151 microns). Seventy-six percent of the branches originated directly from the ACoA. They tended to arise closer to the left than to the right anterior cerebral artery. Fourteen percent of them arose from the junctional site of the ACoA with the anterior cerebral arteries, and 10% from the site of origin of the subcallosal artery. Large branches were identified as the median artery of the corpus callosum, and the subcallosal artery, respectively. The former vessel was present in 9% of the patients, and the latter in 91%. The subcallosal artery was from 320 to 640 microns in size (mean 486 microns). It tended to arise from the middle of the ACoA. In spite of the very frequent anastomoses involving the ACoA branches, care must be taken to avoid injury to these important vessels during operations of the ACoA aneurysms.
The transcription rate of the haptoglobin (Hp) gene is stimulated by interleukin-1 (IL-1), IL-6, and dexamethasone in rat hepatoma (H-35) cells. To identify the cis-acting regulatory elements responsive to these hormones, various lengths of 5' Hp gene-flanking regions, including the promoter, were inserted into chloramphenicol acetyltransferase gene expression vectors and transiently introduced into H-35 cells. The first 4 kb of 5' region mediated a severalfold increase in expression after treatment with IL-6 and dexamethasone. No response to IL-1 was detectable. When, however, upstream sequences were deleted to position -165 relative to the transcription start site, a significant stimulation by IL-1 was gained without appreciably affecting the IL-6 response. With the apparent removal of an inhibitory sequence, the promoter-proximal 165-bp region also displayed a severalfold enhanced response to the combination of dexamethasone, IL-1, and IL-6. The sequence from -165 to -147, termed the A-element, was found to be crucial for all hormone regulatory functions. Two copies of the A-element linked to a heterologous promoter responded to the three hormones, but to a lesser degree than in the Hp gene promoter context. The regulatory elements of the rat Hp gene were similarly active in human hepatoma cells. Optimal regulation by IL-6 in HepG2 cells was, however, independent of the A-element. The A-element functioned in these cells exclusively as an IL-1 response sequence. The results suggest that genomic sequences upstream of the rat Hp gene suppress the regulation by specific cytokines more prominently in transient expression assays than in the normal chromosomal context. Moreover, the functional comparison indicated that specific regulatory regions of the rat Hp gene do not function identically in different hepatic cell types.