Biomedical subjects
Publications and source records attributed to J Jakubowski.
The authors describe the presentation, investigation and successful treatment of two giant serpentine aneurysms with Guglielmi detachable coils. Both aneurysms selectively involved the P2 segment of the posterior cerebral artery. The authors describe an endovascular approach to these challenging lesions as an alternative/adjunct to conventional surgery.
A method of image guidance for neurosurgery using the surgeon's binocular depth perception is described. Magnetic resonance volume acquisitions and surface rendering software were used to produce stereoscopic pairs of images of the surface of the heads of patients with brain tumours. Stereoscopic pairs of the surface rendering of the tumour were also produced. The two pairs of images were colour-coded and combined into one pair of 35-mm slides. A stereoscopic viewer was constructed to allow simultaneous viewing of the pair of slides and the patient's head. Registration was achieved by moving the stereoscope in space until the virtual images of the rendered surface of the head coincided with the real head. The stereoscope was then locked in position and the virtual image of the tumour was projected 'into' the patient's head to allow the surgeon to locate the tumour. The instrument was used in six cases. A lateral accuracy of 10-15 mm was achieved and a depth accuracy of 5-10 mm.
The bursting pressure of samples of cerebral arteries was measured. Eighty-five samples of cerebral arteries were taken from 11 fresh cadavers. These samples were filled with saline under pressure to the point of bursting. The bursting pressures were recorded. The mean bursting pressure of all samples was 1.8 bar (1370 mmHg). The range was 0.7-4.6 (530-3190 mmHg). The mean bursting pressures of samples containing branch points was 1.6 and that of those without branch points was 2.2. This difference was significant with p < 0.001. Samples taken from persons dying from subarachnoid haemorrhage were weaker (mean 1.45 bar) than those taken from persons dying from other causes (mean 1.971 bar). This difference was significant with p < 0.001. Bursting pressure was found to decline at 2% per year of age. This figure was different from 0 with p = 0.003.
BACKGROUND: Percutaneous endoscopic gastrostomy (PEG) may be required in neurosurgical patients with a persistently depressed neurological status or severe lower cranial nerve palsies. Such patients may have a coexisting hydrocephalus requiring cerebrospinal fluid (CSF) diversion. Despite the risk of infection resulting from exposure to oropharyngeal flora by the pull-through PEG technique and the secondary pneumoperitoneum seen in one-third of patients, simultaneous peritoneal placement of CSF shunt catheters with PEG is the current practice. The aim of the study was to determine the frequency of CSF diversionary procedures in neurosurgical patients undergoing PEG insertion and the occurrence of infective complications in patients with simultaneous placement of a PEG and a ventriculoperitoneal (VP) shunt. METHODS: This was a retrospective review of all neurosurgical patients undergoing PEG. The presence of hydrocephalus, mode of CSF diversion and the development of subsequent infection in those having coexistent distal peritoneal catheter placement and PEG were determined. RESULTS: PEGs were placed in 42 neurosurgical patients (9.3 per cent of all PEGs inserted), of whom 21 had a coexisting hydrocephalus. Eight of 16 shunts with distal catheter placement in the peritoneal cavity developed infection requiring revision. Infections occurred with greater frequency in patients with a tracheostomy. There were no shunt infections requiring revision in a second group of 21 patients who had a coexisting shunt and tracheostomy without PEG. CONCLUSION: Simultaneous placement of a PEG and a VP shunt should be avoided in the acute phase of a patient's hospital admission.
We describe a case of a 59-year-old woman who remained drowsy and developed a left hemiparesis following right temporomandibular joint (TMJ) arthrocentesis and lavage for TMJ dysfunction. CT demonstrated an extradural haematoma. This is the first reported case of an extradural haematoma following TMJ arthrocentesis.
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OBJECTIVES: To calculate the expected number of life-years saved by surgical treatment of unruptured intracranial aneurysms at ages over 20 years. METHODS: An actuarial risk analysis of the treatment of unruptured intracranial aneurysms based on data from the International Study of Unruptured Intracranial Aneurysms (ISUIA). The benefits of operative treatment are calculated in terms of average life-years saved. RESULTS: Results are presented as graphs of life-years saved or lost against age at the time of operative treatment for three groups of aneurysms: those under 10 mm in diameter with no history of subarachnoid haemorrhage (SAH) from another aneurysm, those under 10 mm in diameter and a history of previous SAH from a different aneurysm, and those over 10 mm in diameter. Life-years are lost at all ages in the group under 10 mm with no history of SAH. For the group under 10 mm with a history of SAH about 4 years are saved at age 20 declining to 0 at around age 50. For aneurysms 10 mm or more in diameter about 8 life-years are saved at age 20 declining to 0 at around 50. CONCLUSIONS: Clipping of unruptured aneurysms under 10 mm in diameter with no history of subarachnoid haemorrhage is not justified on actuarial grounds. Intervention in other unruptured aneurysms produces benefits in life expectancy up to the age of 50. There may be subgroups of aneurysms in which larger benefits exist.
The recent publication of the results of the international study on unruptured intracranial aneurysms highlighted a paradox: there do not seem to be enough unruptured aneurysms in the population to account for the observed incidence of subarachnoid haemorrhage. Some authors have suggested that the answer to this paradox is that most aneurysms that bleed do so shortly after formation. This would mean that the bulk of subarachnoid haemorrhages come from recently formed rather than long standing aneurysms. This paradox and proposed answer are examined. The available statistics on the incidence of subarachnoid haemorrhage, the prevalence of unruptured aneurysms, and the risk of bleeding from unruptured aneurysms are used to place a maximum on the time interval between aneurysm formation and rupture. For aneurysms less than 10 mm in diameter in persons with no history of subarachnoid haemorrhage, an estimate of less than 42 weeks was made. The null hypothesis that such aneurysms pose a constant risk with time is rejected with p <10(-9). In larger aneurysms the risk seems to be constant with time.
Blood samples were taken from the retrobulbar venous plexus or the sublingual vein of male HamIbm:Wist rats to compare clinical pathology parameters between the two sampling techniques. By analogy with a pharmacokinetic study, blood was sampled six times during one day from unfasted animals. After 3 weeks of recovery, blood was taken from fasted animals on a single occasion. In addition, prolactin and corticosterone levels were determined to compare stress-related effects between the two sampling methods. Body weight development and food consumption were similar after single as well as after repeated blood sampling for the two blood sampling techniques. Haemotological evaluation showed a gradual decrease in erythrocyte count, haemoglobin concentration and haematocrit after repeated blood sampling. Repeated withdrawal of blood samples over 24 h corresponding to approximately 22% of the total blood volume resulted in a decrease in red blood cell parameters by up to 30%. The withdrawal of approximately 10% of the total blood volume was associated with a decrease in these parameters by up to 10% and should not be exceeded for animal welfare reasons and to allow a reliable evaluation of data in a study. Repeated blood sampling was associated with an initial decrease in the number of white blood cells, mainly due to a reduction in lymphocytes; white blood cell counts were slightly increased one day after. The decrease in lymphocytes and the increase in neutrophils after repeated sampling were generally slightly more pronounced in the blood from the retrobulbar plexus than from the sublingual vein. Comparison of serum clinical chemistry data showed significantly higher activities of creatine kinase and aspartate aminotransferase in samples from the retrobulbar plexus. These findings suggest a higher degree of tissue damage with blood sampling from the retrobulbar plexus than from the sublingual vein. Despite a large inter-individual variability, higher mean values of prolactin on each occasion and corticosterone after a single sample in fasted animals indicate a higher stress associated with blood sampling from the retrobulbar plexus.
AIMS/HYPOTHESIS: Experimental studies have shown that abnormalities of nerve microcirculation are important factors in the pathogenesis of diabetic neuropathy but there have been few clinical studies. We have applied microlightguide spectrophotometry to measure intravascular oxygen saturation (HbO2%) and blood flow in human sural nerve. METHODS: We studied ten patients with mild-moderate sensory motor diabetic neuropathy, nine patients without neuropathy and nine control subjects. We took 300 measurements of oxygen saturation under direct visual control through a 1.9 mm rigid endoscope over three regions of the nerve. Spectrophotometric measurements of nerve fluorescence were taken after an intravenous injection of sodium fluorescein and the rate of increase in nerve fluorescence (rise time) was used as an indicator of nerve blood flow. RESULTS: Nerve oxygen saturation was reduced in patients with neuropathy compared with control subjects (67.1 +/- 2.2% vs 76.7 +/- 2.1%, p = 0.006). Fluorescein rise time was prolonged in patients with neuropathy compared with the control group (48.5 +/- 7.0 s vs 14.0 +/- 3.1 s, p = 0.001) suggesting impaired nerve blood flow. There was a correlation between rise time, nerve oxygen saturation, glycaemic control and sural nerve sensory conduction velocity (p < 0.01). CONCLUSION/INTERPRETATION: The combination of microlight-guide spectrophotometry and micro-endoscopy provides a valuable minimally invasive technique for clinical investigation of nerve microcirculation. We have shown reduced nerve oxygenation and impaired blood flow in diabetic neuropathy and these findings strongly support a central role of microvascular disease in the pathogenesis of diabetic neuropathy.
Ras-mediated signaling is required for induction of vulval cell fates during Caenorhabditis elegans development. By screening for suppressors of the multivulva phenotype caused by constitutively active let-60 ras, we identified the mutation n2527. To clone the gene affected by n2527, we developed a method for high-resolution mapping. We took advantage of the genomic DNA sequence of the N2 strain by using DNA sequencing to scan for single-nucleotide polymorphisms (SNPs) at defined genomic positions of the RC301 strain. An average of one polymorphism per 1.4 kb was detected in predicted intergenic regions. Because of this high frequency, DNA sequencing is an efficient method to scan for SNPs. By alternating between identifying SNPs and mapping n2527 using selected recombinants, we generated an SNP map of progressively higher density. An intensive search for SNPs resulted in a local map with an average marker spacing of approximately 4 kb. This was used to map n2527 to a 9.6-kb interval. The small size of this interval made it feasible to use DNA sequencing to identify the molecular lesion. In principle, this approach can be used for high-resolution mapping of any C. elegans mutation. Furthermore, this approach can be applied to other species as the genomic sequence becomes available. The n2527 mutation affects a previously uncharacterized gene that we named cdf-1, as it encodes a predicted protein with significant similarity to members of the cation diffusion facilitator family.
The use of the immunosuppressant cyclosporine A (CsA) is limited by its adverse renal effects. Most recently, we reported that the drug markedly decreases the levels of the calcium-binding protein calbindin-D 28kDa in kidneys of male Wistar rats. In the present study, the potential relationship between drug-induced nephrotoxicity and the decrease in kidney calbindin-D 28kDa was investigated. Four groups of male Wistar rats were treated for 10 or 31 days with either the immunosuppressant CsA (50 mg/kg/day), FK-506 (5 mg/kg/day), rapamycin (5 mg/kg/day) or with the nonimmunosuppressive cyclosporine derivative 3'keto-[Bmt1]-[Val2]-CsA (SDZ PSC-833) (50 mg/kg/day), and the effects on calcium homeostasis, kidney histology and renal calbindin-D 28kDa were examined. Similar effects were found with CsA and FK-506; both drugs strongly reduced kidney calbindin-D 28kDa protein levels, increased urine calcium excretion, caused intratubular calcification, and induced basophilic tubules. In contrast, rapamycin and SDZ PSC-833 caused no decrease in renal calbindin-D 28kDa levels, no noticeable alterations in calcium metabolism, and no renal calcification. The results provide evidence for a link between decreased renal calbindin, increased calcium urine excretion, and intratubular kidney calcification. The present data show no correlation between the decrease in renal calbindin and the induction of basophilic tubules; however, it needs to be investigated if these apparently independent kidney effects may have a common origin upstream of calbindin expression.
Four cases of synovial cyst (ganglion) arising from the facet joints of the lumbar spine are reported. A typical presenting feature was exacerbation of pain on standing or walking, mimicking vascular claudication. MRI proved in all four cases to be the definitive investigation and surgery the treatment of choice, producing excellent results.
OBJECTIVE: To evaluate the use of microvascular decompression (MVD) for the treatment of hemifacial spasm (HFS). METHODS: Eighty three patients with HFS who underwent MVD via a suboccipital craniectomy are presented. RESULTS: Seventy two out of seventy eight patients available for follow up remained free of any spasms at a mean follow up period of eight years. Two patients continued to have minor intermittent muscle twitches and three had recurrence of HFS. One patient's operation was not completed. Twenty had a transient complication and eight were left with permanent postoperative deficits, the commonest being unilateral sensorineural deafness. Seventy one patients declared themselves satisfied with the procedure. A causative vessel was found on the root exit zone of the seventh cranial nerve in 81 patients. CONCLUSION: The procedure seems to provide lasting relief for most patients. The correct operative technique is essential if complications are to be avoided.
The middle cerebral artery (MCA) was irradiated in 94 rats using the Gamma Knife. The vessels receiving 20, 50, 80 and 200 Gy were removed 24 h later and mounted on a myograph. Contractility responses to potassium and prostaglandin (PG) F2 alpha were tested. After precontraction with PGF2 alpha, the relaxant effects of histamine, papaverine, L-arginine and sodium nitroprusside were examined. Other vessels were preincubated with ouabain or N omega-nitro-L-arginine methyl ester before testing with the relaxant agents. After irradiation, the contractile response to maximal potassium and PGF concentrations was diminished, suggesting dose-dependent radiation damage to the contractile mechanism. The normal MCA shows an initial relaxation in the presence of a low K+ concentration, which is Na+, K(+)-ATPase dependent. According to this study, the endothelium-derived relaxation function was suppressed by radiation, suggesting that there is an early change in irradiated vessels, demonstrable by functional studies, which affects both the smooth muscle and endothelial layers.
The article addresses the fascinating topic of blood flow in the normal and the adenomatous anterior pituitary gland. This is considered in conjunction with the anatomy and physiology of the area and the neuro secretion. The mechanisms of the control of the development and growth of the prolactinoma and the changes in the microcirculation of the tumour are discussed. It is felt that its altered microvascular pattern and in particular the influx of the systemic low dopamine blood through the supplementary and newly developed blood supply plays an important role in the natural history of these tumours.
BACKGROUND AND PURPOSE: There is no comprehensive and reliable model available in small animals that is suitable for the study of subarachnoid hemorrhage (SAH). Most of the existing models either require extensive surgery to achieve SAH or neglect the importance of an injury to the vessel and the impact of suddenly raised intracranial pressure (ICP). The presented model is designed to overcome these shortcomings. METHODS: Forty-three male Wistar rats were anesthetized. Regional cerebral blood flow was measured using the H2 clearance method bilaterally in the middle cerebral artery territory. ICP and blood pressure were continuously monitored. Blood gases were kept within physiological limits. SAH was produced by passing a nylon thread up through the right internal carotid artery and piercing a hole in the right anterior cerebral artery. The animals were divided into three experimental groups treated with varied operative techniques. After 3 hours the surviving animals were killed, and SAH was confirmed by postmortem examination. RESULTS: The described method proved to be a reliable way of producing SAH in rats. The onset of SAH was characterized by a sudden increase in ICP. There were some differences in the reduction of regional cerebral blood flow and the survival rate in the experimental groups. This may represent differing degrees of severity of the produced SAH. CONCLUSIONS: We present an inexpensive and reliable model of SAH in the rat that allows the early course of biochemical, physiological, and pathological changes to be studied.
Reactive airways dysfunction syndrome (RADS) is an asthma-like bronchoconstriction state which develops after a short-term exposure to highly irritating volatile substances. Although some of the clinical manifestations can be considered as very similar to those of asthma (e. g. inflammation, hyperresponsiveness and reversibility of the bronchial constriction) the most essential difference lies in the absence of asthma attacks after exposure to small amounts of causative agents few weeks after onset. Thus, the mechanism of RADS cannot be considered to be of an allergic origin. This is supported by the results of the pathomorphologic biopsies taken from bronchi which usually show neutrophilic and lymphocytic infiltrations as well as frequent and severe destruction of the bronchial epithelium. Eosinophilic infiltrations and basement membrane thickness have never been found. The therapy of severe dyspnoea attacks is similar to that of bronchial asthma. Factors that cause RADS comprise a wide range of volatile irritant substances, provided that they occur in high concentrations. Exposure to isocyanates in plumbers heating polyurethane pipes seems to be the major cause of RADS in Poland.