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Biomedical subjects

P Miklić

Publications and source records attributed to P Miklić.

14 recordsLinked to original sources
PubMed2005

The keyhole concept in aneurysm surgery--a comparative study: keyhole versus standard craniotomy.

OBJECTIVE: The purpose of the study is to compare the results of minimally invasive keyhole craniotomy and standard larger craniotomies in the surgical treatment of patients with intracranial aneurysms. METHODS: In the past eight years 628 patients were operated by two experienced neurosurgical teams. The first group of 482 patients with 565 aneurysms were operated through a small keyhole craniotomy, using the eyebrow keyhole approach in particular. The remaining 146 patients with 167 aneurysms were operated using a standard craniotomy that included pterional/frontotemporal, frontoparietal parasagittal, and retrosigmoid suboccipital craniotomies. All operations were performed in the standard microsurgical technique using intraoperative evoked potential monitoring and endoscopic assistance in selected cases. RESULTS: Most supratentorial aneurysms and basilar tip aneurysms were successfully operated through an eyebrow keyhole craniotomy. Distal MCA aneurysms as well as aneurysms on the MCA with a long M1 segment were operated through a temporal keyhole, and aneurysms of the distal PCA (P2-P3) segment subtemporally. The frontoparietal parasagittal keyhole approach was used only for pericallosal artery aneurysms. Infratentorial aneurysms of the VA/PICA complex were operated via a retrosigmoid approach. On comparing the surgery results in patients with a keyhole craniotomy and those with standard craniotomy, similar outcomes were found for both groups, with excellent or very good outcomes (GOS 5 and 4) in 398 (82.57%) patients from the keyhole craniotomy group, and in 116 (79.45%) patients from the standard craniotomy group. The mortality rate in the keyhole group was 0.83% (4 patients) and 2.05% (3 patients) in the standard craniotomy group. CONCLUSION: Parallel treatment results in using two options--keyhole craniotomy and standard larger craniotomy--were analysed in the past eight years. Two experienced neurosurgical teams in performing both surgical approaches have reached almost similar morbidity and mortality rates, and overall surgical results. The type of craniotomy is selected according to the experience of the surgical team, and familiarity with certain approach. The authors have good experience with the minimally invasive approach for different intracranial pathology and recommend it especially in neurovascular surgery.

Adolescent↗
PubMed1999

Creutzfeldt-Jakob disease in a patient with a lyophilized dura mater graft.

A 37-year-old patient with Creutzfeldt-Jakob disease (CJD) is presented, who had received a cadaveric dura matter graft 12 year before the onset of neurologic symptoms. Initial clinical presentation included cerebellar symptoms, with dementia and myoclonus developing in later stages of the disease. EEG showed diffuse slowing with sporadic triphasic periodic activity. CT was normal in the early stage but pronounced cerebral and cerebellar atrophy with widened sulci were seen on MRI in the late stage of the disease. The prion protein (PrP) gene was homozygous for valin at the polymorphic codon 129. Cerebrospinal fluid analysis for 14-3-3 protein was positive. We believe that this patient is the first Croatian to acquire CJD by dural implant. Based on this case and a review of 66 cases from the literature, it is manifest that the awareness of iatrogenic transmission of CJD and adoption of preventive measures are the only effective way to stop the spread of CJD among surgically treated patients.

Adult↗
PubMed1997

The influence of a novel pentadecapeptide, BPC 157, on N(G)-nitro-L-arginine methylester and L-arginine effects on stomach mucosa integrity and blood pressure.

The known effects of a novel stomach pentadecapeptide BPC157 (10 microg or 10 ng/kg), namely its salutary activity against ethanol (96%, i.g.)-induced gastric lesions (simultaneously applied i.p.) and in blood pressure maintenance (given i.v.), were investigated in rats challenged with a combination of N(G)-nitro-L-arginine methylester (L-NAME) (5 mg/kg i.v.), a competitive inhibitor of endothelium nitric oxide (NO)-generation and NO precursor, L-arginine (200 mg/kg i.v.) (D-arginine was ineffective). In the gastric lesions assay, NO agents were given 5 min before ethanol injury and BPC 157 medication. Given alone, BPC157 had an antiulcer effect, as did L-arginine, but L-NAME had no effect. L-NAME completely abolished the effect of L-arginine, whereas it only attenuated the effect of BPC 157. After application of the combination of L-NAME + L-arginine, the BPC157 effect was additionally impaired. In blood pressure studies, compared with L-arginine, pentadecapeptide BPC 157 (without effect on basal normal values) had both a mimicking effect (impaired L-NAME-blood pressure increase, when applied prophylactically and decreased already raised L-NAME values, given at the time of the maximal L-NAME-blood pressure increase (i.e., 10 min after L-NAME)) and preventive activity (L-arginine-induced moderate blood pressure decrease was prevented by BPC 157 pretreatment). When BPC 157 was given 10 min after L-NAME + L-arginine combination, which still led to a blood pressure increase, its previously clear effect (noted in L-NAME treated rats) disappeared. In vitro, in gastric mucosa from rat stomach tissue homogenates, BPC 157, given in the same dose (100 microM) as L-arginine, induced a comparable generation of NO. But, BPC 157 effect could not be inhibited by L-NAME, even when L-NAME was given in a tenfold (100 versus 1000 microM) higher dose than that needed for inhibition of the L-arginine effect. NO synthesis was blunted when the pentadecapeptide BPC 157 and L-arginine were combined. In summary, BPC 157 could interfere with the effects of NO on both gastric mucosal integrity and blood pressure maintenance in a specific way, especially with L-arginine, having a more prominent and/or particularly different effect from that of NO.

Animals↗
PubMed1997

Pentadecapeptide BPC 157 interactions with adrenergic and dopaminergic systems in mucosal protection in stress.

Since superior protection against different gastrointestinal and liver lesions and antiinflammatory and analgesic activities were noted for pentadecapeptide BPC (an essential fragment of an organoprotective gastric juice protein named BPC), the beneficial mechanism of BPC 157 and its likely interactions with other systems were studied. Hence its beneficial effects would be abolished by adrenal gland medullectomy, the influence of different agents affecting alpha, beta, and dopamine receptors on BPC 157 gastroprotection in 48 h restraint stress was further investigated. Animals were pretreated (1 hr before stress) with saline (controls) or BPC 157 (dissolved in saline) (10 microg or 10 ng/kg body wt intraperitoneally or intragastrically) applied either alone to establish basal conditions or, when manipulating the adrenergic or dopaminergic system, a simultaneous administration was carried out with various agents with specific effects on adrenergic or dopaminergic receptors [given in milligrams per kilogram intraperitoneally except for atenolol, which was given subcutaneously] phentolamine (10.0), prazosin (0.5), yohimbine (5.0), clonidine (0.1) (alpha-adrenergic domain), propranolol (1.0), atenolol (20.0) (beta-adrenergic domain), domperidone (5.0), and haloperidol (5.0) (peripheral/central dopamine system). Alternatively, agents stimulating adrenergic or dopaminergic systems--adrenaline (5.0) or bromocriptine (10.0)--were applied. A strong protection, noted following intragastric or intraperitoneal administration of BPC 157, was fully abolished by coadministration of phentolamine, clonidine, and haloperidol, and consistently not affected by prazosin, yohimbine, or domperidone. Atenolol abolished only intraperitoneal BPC 157 protection, whereas propranolol affected specifically intragastric BPC 157 protection. Interestingly, the severe course of lesion development obtained in basal conditions, unlike BPC 157 gastroprotection, was not influenced by the application of these agents. In other experiments, when adrenaline and bromocriptine were given simultaneously, a strong reduction of lesion development was noted. However, when applied separately, only adrenaline, not bromocriptine, has a protective effect. Thus, a complex protective interaction with both alpha-adrenergic (eg, catecholamine release) and dopaminergic (central) systems could be suggested for both intragastric and intraperitoneal BPC 157 administration. The involvement of beta-receptor stimulation in BPC 157 gastroprotection appears to be related to the route of BPC 157 administration. The demonstration that a combined stimulation of adrenergic and dopaminergic systems by simultaneous prophylactic application of adrenaline (alpha- and beta-receptor stimulant) and bromocriptine (dopamine receptor agonist) may significantly reduce restraint stress lesions development provides insight for further research on the beneficial mechanism of BPC 157.

Adrenergic Agents↗
PubMed1997

Pentadecapeptide BPC 157, cimetidine, ranitidine, bromocriptine, and atropine effect in cysteamine lesions in totally gastrectromized rats: a model for cytoprotective studies.

A superior effectiveness in various lesion assays was noted for the novel pentadecapeptide BPC 157, originated from human gastric juice protein (BPC) and claimed to be a cytoprotective agent. From this viewpoint, as a previously untreated experimental improvement to create an acid-free environmental for cytoprotection studies, total gastrectomy was done 24 hr before the ulcerogenic procedure. In the absence of stomach and gastric acid, the damaging effects of cysteamine (400 mg/kg subcutaneously, death 24 hr thereafter), to date thought to be an acid-related duodenal ulcerogen, and the BPC 157 cytoprotective effect (10 microg or 10 ng/kg intraperitoneally) were further challenged. BPC 157 was compared with reference agents [cimetidine (50), ranitidine (10), omeprazole (10), bromocriptine (10) and atropine (10) (mg/kg intraperitoneally, 1 hr before cysteamine] known to be also cytoprotective. In naive rats, with intact stomach, all of them showed a strong beneficial effect. Interestingly, in gastrectomized animals, the application of BPC 157 or the reference agents before cysteamine significantly prevented the otherwise severe duodenal lesion development noted in the control gastrectomized cysteamine rats. In groups without cysteamine, no lesions were noted (laparotomy, gastrectomy only, 24 or 48 hr postsurgical period), nor was lesion potentiation seen in cysteamine-treated laparotomized animals. In summary, these findings--equal damaging effect of cysteamine and equal protection of pentadecapeptide BPC 157 and reference agents in gastrectomized and rats with intact stomach--seem to be particularly relevant for a cytoprotective viewpoint. Without a stomach, the cysteamine damaging effect was convincingly defined as an essential gastric acid-independent injury (analogous to ethanol gastric lesions). Likewise, a high "cytoprotective capacity," apparently acid independent, common for all tested agents (novel pentadecapeptide BPC 157, cimetidine, ranitidine, omeprazole and atropine) could be clearly stressed.

Animals↗
PubMed1996

Beneficial effect of a novel pentadecapeptide BPC 157 on gastric lesions induced by restraint stress, ethanol, indomethacin, and capsaicin neurotoxicity.

Very recently, the integrity of capsaicin somatosensory neurons and their protection were suggested to be related to the activity in nociception of a newly discovered 15-amino acid peptide, BPC 157, shown to have strong beneficial effect on intestinal and liver lesions. Therefore, from this viewpoint, we have studied the gastroprotective effect of the pentadecapeptide BPC 157, on gastric lesions produced in rats by 96% ethanol, restraint stress, and indomethacin. The possible involvement of sensory neurons in the salutary actions of BPC 157 (10 micrograms/kg, 10 ng/kg intraperitoneally) was studied with capsaicin, which has differential effects on sensory neurons: a high dose in adult (125 mg/kg subcutaneously, 3 months old) or administration (50 mg/kg subcutaneously) to neonatal animals (age of the 7 days) destroys sensory fibers, whereas a low dose (500 micrograms/kg intraperitoneally) activates neurotransmitter release and protective effects on the mucosa. In the absence of capsaicin, BPC 157 protected gastric mucosa against ethanol, restraint, and indomethacin application. In the presence of neurotoxic doses of capsaicin, the negative influence of capsaicin on restraint, ethanol, or indomethacin lesions consistently affected salutary activity of BPC 157. However, BPC 157 protection was still evident in the capsaicin-treated rats (either treated as adults or as newborns) in all of these assays. Interestingly, after neonatal capsaicin treatment, a complete abolition of BPC gastroprotection was noted if BPC 157 was applied as a single nanogram-regimen, but the mucosal protection was fully reversed when the same dose was used daily. In line with the excitatory dose of capsaicin the beneficial effectiveness of BPC 157 appears to be increased as well. Taken together, these data provide evidence for complex synergistic interaction between the beneficial effectiveness of BPC 157 and peptidergic sensory afferent neuron activity.

Age Factors↗
PubMed1995

Outcome of post-traumatic unawareness persisting for more than a month.

From 1986 to the end of 1991, 19 patients with persisting post-traumatic unawareness were admitted for rehabilitation. Criteria for admission were head trauma, Glasgow coma scale score < or = 8 points, and at least a one month duration of unawareness. Out of 19 patients, 12 patients (63%) regained consciousness, 11 patients (58%) within the first year and one patient (5%) within the second year. The mean duration of unawareness in the patients who recovered consciousness was 190 (range 62-440) days. In the recovery group, according to the Glasgow outcome scale, seven out of 12 patients (58%) were moderately disabled and five (42%) were severely disabled at the moment of discharge from rehabilitation. All the 12 patients who regained consciousness live with their families, and none had to be kept in an institution. The data confirm that awakening from post-traumatic unawareness is possible after a long period. Therefore, post-traumatic unawareness persisting for more than a month should not be considered an irreversible condition, because an outcome that might be regarded by some as being acceptable is possible even in patients with very severe brain damage.

Adult↗
PubMed1991

Dumbbell meningioma of the cervico-clavicular region.

The authors are reporting on a case of a 55-year-old man with an epidural meningioma in the region from the C VII. to the Th I. segment. The tumor encircled this region, and to the front and right involved the channels through which pass the C VI, C VII. and C VIII. roots. Subdurally, no tumoral mass was found. Another part of this tumor, of the same histological architecture as the epidural cervicospinal part was found in the supraclavicular region to the right, closely connected to the arteries and nerves of this region. The authors discuss the possibility of the tumoral occurrence at this site, primarily taking into account the origin of this tumor from the cells of the outer surface of the arachnoidea, i.e. cap cells which can invade the dura, with later separation from the main arachnoidal layer. The other possibility of such dumbbell meningioma occurring at the outgoing openings of the neural paths from the spinal channel should be looked for in the remnants of the arachnoidal cells in the region of the outgoing openings. In the paper are also discussed and correlated clinico-pathological, CT and angiographic findings.

Humans↗
PubMed1976

[Aequidensitometrie of the labyrinthic capsule with special regard of the bottom of the internal auditory meatus].

It has been proved by densitometry that the thickness of the separating wall between the basal coil and the fundus of the internal auditory meastus as well as the thickness of the labyrinthic wall increase with age. The mineral contents is simultaneously reduced. The diameter of the cochlear canal is also reduced with age. These facts have been demonstrated by aequidensitometry and by summation color pictures of aequidensites.

Adolescent↗
PubMedDate not supplied

Further contribution in the densitometric study of the labyrinthic capsule with special reference to the bottom of the internal auditory meatus.

The quantity of minerals in the labyrinthic capsule of the basal coil and of the separating wall facing the internal auditory meatus in different life periods was determined by the densitometric method. The quantity of minerals is reduced in the labyrinthic capsule and in the separating wall in spite of the bone apposition and increasing thickness of the separating wall.

Adolescent↗
PubMedDate not supplied

[Use of intraoperative ultrasound in neurosurgery].

Intraoperative ultrasound (US) is a device which is a great help to neurosurgeon in intracerebral lesions localization, in the definition of inner tumors structure, in its relation to the surrounding structures, as well as during stereotaxic operations. We report our experiences with US in more than 500 operations. Its maximum usage is during gliomas and metastases operations because of their subcortical localization. Choosing this optimal approach to the tumor, the surrounding brain is minimally damaged. Using modern devices we are able to distinguish edema from infiltrative gliomas, which was not possible using former devices (both edema and gliomas are hyperechoic). In vascular neurosurgery we use US mostly in the localization of small arteriovenous malformations (AVMs). In pediatric neurosurgery the usage is very often in drainage operations for ventricular catheter placement control. The main US shortage is lower image resolution, and the basic advantage is real time imaging. It enables our prompt intervention in every unfavorable situation.

Brain↗