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Dyke PH, Stratford J. Changes to the TEF schemes can have significant impacts on regulation and management of PCDD/F and PCB. CHEMOSPHERE 2002; 47:103-116. [PMID: 11993627 DOI: 10.1016/s0045-6535(01)00219-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The changes recommended by the World Health Organisation (WHO) to the toxic equivalency factors (TEFs) for polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) and the recommendation to extend both the TEF scheme and the tolerable daily intake (TDI) to include "dioxin-like" PCB congeners have significant implications for regulators who have relied heavily on the International TEF (I-TEF) scheme in setting and monitoring limits and exposure to these compounds. This paper examines example data sets of sources, environmental concentrations, food and exposure to indicate likely changes in calculated toxic equivalent (TEQ) due to the recommended changes to TEFs. Many published data sets available do not provide congener specific data for PCDD/F which limits the ability to recalculate TEQs. There are even fewer congener specific data published to enable calculation of TEQs for the dioxin-like PCBs. In general TEQs calculated using the WHO scheme for emissions to air were found to show small increases (in the order of 1-10%) in comparison to the I-TEQ (for PCDD/F), some sludge samples showed substantial decreases (up to 70%). Levels in food and calculations of exposure showed that the change to TEFs for PCDD/F increased calculated exposure by 10-20% while the change to PCB TEFs decreased calculated TEQ attributable to PCB by 0-10%. The effects of including PCB in the overall TEQ and the changes to TEFs for PCDD/F substantially increase calculated TEQ exposure. Congener specific data should be presented to allow calculation of desired TEQ and the impact of the changes on emission limits, regulations on sludge use and environmental quality standards should all be carefully considered. The absence of data on emissions of dioxin-like PCB means that it is not possible to estimate with any certainty the impact on overall TEQ emissions of including the nominated PCB. Given the potential for confusion with the proliferation of TEFs and the extension to include both PCDD/F and PCB in the calculation of TEQs it is important that great care is taken to clearly express which compounds are included and which TEF scheme has been applied in each case.
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Booth MI, Jones L, Stratford J, Dehn TCB. Results of laparoscopic Nissen fundoplication at 2-8 years after surgery. Br J Surg 2002; 89:476-81. [PMID: 11952591 DOI: 10.1046/j.0007-1323.2002.02074.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Although the long-term results of open fundoplication for gastro-oesophageal reflux disease are well documented, there have been few reports of the long-term results of laparoscopic fundoplication. METHODS Between January 1993 and July 1999, 179 consecutive patients underwent laparoscopic floppy Nissen fundoplication. Of these, 175 were available for long-term follow-up. Structured symptom questionnaires were completed by 140 patients (80 per cent) at 2-5 years (n = 92) or 5-8 years (n = 48) after operation. RESULTS Patient satisfaction with surgery was 91 per cent at a median follow-up of 48 (range 24-99) months. Visick scores of I or II were recorded by 84 per cent. Ninety per cent of patients remained free from significant reflux symptoms. Side-effects were common (22 per cent) but rarely affected patient satisfaction. Of the 19 patients (14 per cent) taking regular antireflux medication, eight used it for non-reflux symptoms and 12 had normal postoperative pH tests. CONCLUSION Laparoscopic floppy Nissen fundoplication is an effective and durable treatment for gastro-oesophageal reflux disease. Longer-term follow-up of patients operated on beyond the learning curve can be expected to show further improvements in surgical outcome.
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Booth MI, Stratford J, Dehn TC. Patient self-assessment of test-day symptoms in 24-h pH-metry for suspected gastroesophageal reflux disease. Scand J Gastroenterol 2001; 36:795-9. [PMID: 11495072 DOI: 10.1080/003655201750313298] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Marked daily fluctuations may occur in the pattern and degree of gastroesophageal reflux (GOR) and in patients' symptoms. The aim of this study was to observe how patients' self-assessment of their symptoms on the day of a 24-h pH test correlates with the likely outcome of the test and the potential value in repeating it. METHODS 367 patients with symptoms suggestive of GOR underwent 24-h pH tests. Fifty-eight patients had repeat studies. Patients assessed the severity of their test-day symptoms as 'better than typical', 'typical' or 'worse than typical'. RESULTS A 'typical' or 'worse than typical' day was more likely to produce an abnormal test result (P < 0.0001). A normal first test on a 'better than typical' day was more likely to be followed by an abnormal second test than a normal first test on a 'typical' or 'worse than typical' day (55% versus 22%; P = 0.025). The symptom index score, the total acid exposure time on the first test and the presence of oesophagitis were not associated with an abnormal second test (P not significant). CONCLUSIONS Patients' self-assessment of the severity of their test-day symptoms should be included in the interpretation of 24-h pH tests for suspected GOR. Patients with a normal pH test on a 'better than typical day warrant a repeat test.
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Booth MI, Stratford J, Thompson E, Dehn TC. Laparoscopic antireflux surgery in the treatment of the acid-sensitive oesophagus. Br J Surg 2001; 88:577-82. [PMID: 11298628 DOI: 10.1046/j.1365-2168.2001.01742.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Approximately 10 per cent of patients referred for 24-h oesophageal pH tests with symptoms suggestive of gastro-oesophageal reflux disease will have a normal endoscopic examination and normal distal oesophageal acid exposure times, but a clear temporal correlation between their symptoms and episodes of acid reflux. These patients have an 'acid-sensitive oesophagus', which forms part of the spectrum of reflux-related conditions. Their response to antireflux surgery has not been reported previously. This study represents a prospective cohort analysis of a clearly defined group of patients with acid-sensitive oesophagus who have undergone laparoscopic antireflux surgery. METHODS Nineteen patients (nine male and ten female; median age 32 years) underwent laparoscopic antireflux surgery for acid-sensitive oesophagus. All had had an incomplete response to medical therapy. RESULTS Eighteen of 19 patients were graded Visick I or II at 6 months after operation; all 16 patients followed for 1 year were graded Visick I or II. There were significant falls in DeMeester symptom score (4.0 versus 0.5; P < 0.001), symptom events (20 versus none; P < 0.001), number of reflux episodes (17 versus two; P < 0.001) and overall acid exposure times (1.2 versus 0.3 per cent; P < 0.001) after operation. CONCLUSION Laparoscopic antireflux surgery is a valid and effective treatment for patients with an acid-sensitive oesophagus. Presented in poster form to the British Society of Gastroenterology, Birmingham, March 2000 and the American Gastroenterological Association, San Diego, May 2000
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Preul MC, Feindel W, Dagi TF, Stratford J, Bertrand G. Arthur Roland Elvidge (1899-1985): contributions to the diagnosis of brain tumors and cerebrovascular disease. J Neurosurg 1998; 88:162-71. [PMID: 9420095 DOI: 10.3171/jns.1998.88.1.0162] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The contributions of Arthur Elvidge (1899-1985), Wilder Penfield's first neurosurgical recruit, to the development of neurosurgery have been relatively neglected, although his work in brain tumors extended the previous work of Percival Bailey and Harvey Cushing. He published rigorous correlations of clinical and histological information and formulated a revised, modern nosology for neuroepithelial tumors, including a modern histological definition of glioblastoma multiforme. Well ahead of his time, he believed that glioblastoma was not strictly localized and was the first to comment that the tumor frequently showed "satellitosis." He was the first neurosurgeon in North America to use angiography as a radiographic aid in the diagnosis of cerebrovascular disease. Having studied with Egas Moniz, he was the first to detail the use of angiographic examinations specifically for demonstrating cerebrovascular disorders, believing that it would make possible routine surgery of the intracranial blood vessels. Seeking to visualize all phases of angiography, he was the impetus behind the design of one of the first semi-automatic film changers. Elvidge and Egas Moniz made the first observations on thrombosis of the carotid vessels independently of each other. Elvidge elucidated the significance of embolic stroke and commented on the ischemic sequelae of subarachnoid hemorrhage. Besides his contributions to neurosurgery, he codiscovered the mode of transmission of poliomyelitis. Elvidge's soft-spoken manner, his dry wit and candor, mastery of the understatement, love of exotic travel, and consummate dedication to neurosurgery made him a favorite of patients, neurosurgery residents, nurses, and other hospital staff. His accomplishments and example as teacher and physician have become part of neurosurgery's growing legacy.
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Abstract
BACKGROUND A 20-year-old woman with a right occipital condylar fracture and bilateral hypoglossal nerve injury is presented. Only 17 cases of condylar fracture have been reported in the literature. METHODS The patient was evaluated with plain films, coronal and axial cut CT, and MRI. RESULTS MRI showed a severely distorted but otherwise normal medulla and a displaced condylar bone fragment. CONCLUSION Condylar fracture may cause twelfth nerve palsy by injuring the central or peripheral nerve.
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Stratford J, Wright MA, Reineke W, Mokross H, Havel J, Knowles CJ, Robinson GK. Influence of chlorobenzoates on the utilisation of chlorobiphenyls and chlorobenzoate mixtures by chlorobiphenyl/chlorobenzoate-mineralising hybrid bacterial strains. Arch Microbiol 1996; 165:213-8. [PMID: 8599540 DOI: 10.1007/bf01692864] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Chlorobenzoates (CBA) arise as intermediates during the degradation of polychlorinated biphenyls (PCBs) and some chlorinated herbicides. Since PCBs were produced as complex mixtures, a range of mono-, di-, and possibly trichloro-substituted benzoates would be formed. Chlorobenzoate degradation has been proposed to be one of the rate-limiting steps in the overall PCB-degradation process. Three hybrid bacteria constructed to have the ability to completely mineralise 2-, 3-, or 4-monochlorobiphenyl respectively, have been studied to establish the range of mono- and diCBAs that can be utilised. The three strains were able to mineralise one or more of the following CBAs: 2-, 3-, and 4-monochlorobenzoate and 3,5-dichlorobenzoate. No utilisation of 2,3-, 2,5-, 2,6-, or 3,4-diCBA was observed, and only a low concentration (0.11 mM) of 2,4-diCBA was mineralised. When the strain with the widest substrate range (Burkholderia cepacia JHR22) was simultaneously supplied with two CBAs, one that it could utilise plus one that it was unable to utilise, inhibitory effects were observed. The utilisation of 2-CBA (2.5 mM) by this strain was inhibited by 2,3-CBA (200 microM) and 3,4-CBA (50 microM). Although 2,5-cba and 2,6-cba were not utilised as carbon sources by strain jhr22, they did not inhibit 2-cba utilisation at the concentrations studied, whereas 2,4-cba was co-metabolised with 2-cba. The utilisation of 2-, 3-, and 4-chlorobiphenyl by strain JHR22 was also inhibited by the presence of 2,3- or 3,4-diCBA. We conclude that the effect of the formation of toxic intermediates is an important consideration when designing remediation strategies.
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Stratford J, Dias AE, Knowles CJ. The utilization of thiocyanate as a nitrogen source by a heterotrophic bacterium: the degradative pathway involves formation of ammonia and tetrathionate. MICROBIOLOGY (READING, ENGLAND) 1994; 140 ( Pt 10):2657-62. [PMID: 8000536 DOI: 10.1099/00221287-140-10-2657] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A Gram-negative soil bacterium (isolate 26B) has been shown to utilize up to 100 mM thiocyanate as a source of nitrogen when supplied with glucose as the source of carbon and energy. During growth of isolate 26B with thiocyanate as the source of nitrogen, no ammonia, nitrate, nitrite, cyanide, cyanate, sulfate, sulfite, sulfide or carbonyl sulfide was detected in the growth medium. Growth of the bacterium on 14C-labelled thiocyanate (1.6 microCi) and glucose, yielded 14C-labelled carbon dioxide (0.9 microCi). The addition of 2.9 mM thiocyanate to a bacterial suspension in phosphate buffer (50 mM, pH 7.4) resulted in the utilization of 2.1 mM thiocyanate and the production of 2.0 mM ammonia. This activity was inducible and only occurred after growth of the bacterium with thiocyanate as the source of nitrogen. Tetrathionate (0.7 mM) was detected in the medium after the utilization of thiocyanate (2.4 mM) by a suspension of the bacterium in phosphate buffer, and thiosulfate (1.0 mM) was detected as an intermediate. The addition of sulfide or thiosulfate to the bacterial suspension also resulted in the formation of tetrathionate. The utilization of both of these compounds appeared to be constitutive. A pathway for thiocyanate utilization by isolate 26B is proposed which involves the hydrolysis of thiocyanate to produce cyanate and sulfide. The cyanate then undergoes further hydrolysis to form ammonia and carbon dioxide. The sulfide is ultimately oxidized to tetrathionate via a pathway which includes thiosulfate.
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Preul MC, Stratford J, Bertrand G, Feindel W. Neurosurgeon as innovator: William V. Cone (1897-1959). J Neurosurg 1993; 79:619-31. [PMID: 8410237 DOI: 10.3171/jns.1993.79.4.0619] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Neurosurgeons are well known for being productive researchers and innovators. Few, however, have possessed the prolific ingenuity of William Cone. In 1934, he and William Penfield were cofounders of the Montreal Neurological Institute where, until 1959, he filled the twin roles of neurosurgeon-in-chief and neuropathologist. Because he did not find writing easy, many of his technical inventions and refinements remained unpublished. His numerous innovations included the extensive use of twist-drill technique for biopsy, drainage for subdural hematoma and cerebral abscess, and ventriculography. In the mid-1940's, he developed power tools driven by nitrogen that led to the modern, universally used air-driven tool systems. He had a special interest in the treatment of spinal dysfunction, for which he invented the Cone-Barton skull-traction tongs along with the Cone spinal operating table. He also devised operative procedures for vertebral fracture-dislocation and craniospinal anomalies. For the maintenance of muscle tone in the paralyzed bladder, he constructed a tidal drainage system. He introduced and popularized ventriculoperitoneal shunting techniques and carried out some of the earliest experimental trails to treat brain infections with sulphonamide and antibiotic drugs. He designed his own set of surgical suction devices, bone rongeurs, and a personal suction "air-conditioning" system for each surgeon. He had a keen early interest in intracranial tumors, and also demonstrated on monkeys how subdural mass lesions caused pupillary dilation and mesial temporal lobe damage due to cerebral compression. His work for the military during World War II on effects of altitude on brain pressure remained classified for many years. The first clipping and excision of an intracranial aneurysm is attributed to Cone. Although Penfield was known as "the Chief," Cone was referred to as "the Boss." His fervent dedication to provide total care to his patients was expressed in round-the-clock vigils; he did not separate "nursing" from "surgical" care. Ultimately, Cone's driving passion for perfection led in part to his tragic death. His accomplishments, inventions, and his example as teacher and physician have become part of neurosurgery's collective legacy.
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Noakes PG, Bennett MR, Stratford J. Migration of Schwann cells and axons into developing chick forelimb muscles following removal of either the neural tube or the neural crest. J Comp Neurol 1988; 277:214-33. [PMID: 3068263 DOI: 10.1002/cne.902770205] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A study has been made of the effects of neural crest and neural tube removal at the brachial level on the migration of Schwann cells and axons into the flexor digitorum profundus (fdp) and flexor carpi ulnaris (fcu) muscles of the avian forelimb. The identification of Schwann cells was based on the assumption that antibody HNK-1 uniquely labels these cells at the growing end of limb nerves. Myotubes and nerves were identified by using antibodies to myosin and to neurofilament protein, respectively. The removal of neural crest cells at stage 13 gave a complete Schwann cell-free embryo at the brachial level. Motor axons only grew to the base of the forelimb, forming a rudimentary plexus by stage 27, and failed to penetrate the limb. Removal of the neural tube at stage 13 did not prevent sensory axons from forming a plexus at the base of the limb; these axons subsequently developed into the brachialis longus inferior (bli n) and superior (bls n) nerves. By stage 27 the bli n had branched into the interosseus nerve (in n) and the medial-ulnar nerve (m-u n) trunks. However, unlike the result in control embryos, no nerves were detected amongst the developing fdp and fcu muscles, thus indicating that sensory axons do not grow into the muscles in the absence of motor axons. In contrast, Schwann cells were observed amongst the myotubes at the level of the in n and m-u nerve trunks. The present observations show that motor axons do not enter the limb bud and innervate limb muscles in the absence of Schwann cells. Furthermore, in the absence of motor axons (neural-tube-removed embryos) sensory axons still enter the limb (behind migrating Schwann cells) but fail to innervate developing muscles even though Schwann cells are present among the developing myotubes.
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Lal S, Wood PL, Kiely ME, Etienne P, Gauthier S, Stratford J, Ford RM, Dastoor D, Nair NP. CSF acetylcholinesterase in dementia and in sequential samples of lumbar CSF. Neurobiol Aging 1984; 5:269-74. [PMID: 6531064 DOI: 10.1016/0197-4580(84)90002-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Acetylcholinesterase (AchE) activity (nmol/ml/min) was measured in lumbar CSF from 11 patients with dementia of the Alzheimer type (DAT), 8 patients with Korsakoff psychosis and 33 patients with low back pain who were undergoing myelography (controls). There was no significant difference in enzyme activity between the three groups. There was no significant correlation between age and AchE activity. AchE was also measured in 20 two-ml samples of CSF collected sequentially by lumbar puncture in two neurosurgical patients who had been recumbent for at least 8 hours. Variations in AchE between samples were small. In neither patient was there an increase in AchE activity with progressive sampling. These data indicate that (1) AchE is unchanged in Korsakoff psychosis (2) decreases in brain AchE which are found in DAT are not readily reflected in lumbar CSF (3) AchE in lumbar CSF has a diffuse origin including spinal cord (4) CSF AchE activity is unlikely to be a useful clinical marker for DAT.
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Abstract
A 53-year-old woman with assimilation of the atlas to the occiput presented with paraesthesiae in the right half of her tongue and ipsilateral neck pain aggravated by head turning. After being intermittent for several years, the symptoms eventually became persistent and increasingly incapacitating. At operation, the C2 spinal nerves were found to be compressed by protuberant atlanto-axial joints, particularly on the right side. The superficial parts of the resected C2 spinal nerves showed a loss of both myelinated and unmyelinated nerve fibres. After operation, the patient experienced partial relief of her symptoms.
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Kiely ME, Lal S, Stratford J, Ford RM. Cyclic GMP in sequential samples of lumbar CSF in man. Prog Neuropsychopharmacol Biol Psychiatry 1984; 8:691-4. [PMID: 6099591 DOI: 10.1016/0278-5846(84)90039-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
cGMP was measured in 15 and 20 sequential 2 ml samples of CSF withdrawn by lumbar puncture in two patients respectively who were recumbent for at least 8 hours. cGMP showed a significant linear increase in concentration with progressive sampling (r = 0.70, p less than 0.01; r = 0.59, p less than 0.01, respectively). These data indicate (a) the presence of a rostrocaudal gradient in CSF cGMP (b) recumbency and volume of CSF are important variables to consider in clinical studies (c) the cerebellum may be a source of cGMP in lumbar CSF.
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Simpson J, Howe M, Morris N, Stratford J. Velocity shear in the steps below the Mediterranean outflow. ACTA ACUST UNITED AC 1979. [DOI: 10.1016/0198-0149(79)90005-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Rosenthall L, Chan J, Sidhu R, Stratford J. Combined radiocontrast and radionuclide cerebral angiography. Radiology 1969; 92:1223-8. [PMID: 5790630 DOI: 10.1148/92.6.1223] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Rosenthall L, Aguayo A, Stratford J. A clinical assessment of carotid and vertebral artery injection of macroaggregates of radioiodinated albumin (MARIA) for brain scanning. Radiology 1966; 86:499-505. [PMID: 5931778 DOI: 10.1148/86.3.499] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Rosenthall L, Aguayo A, Stratford J. Vertebral artery injection of macroaggregates of radioiodinated albumin for brain scanning. A preliminary report. JOURNAL OF THE CANADIAN ASSOCIATION OF RADIOLOGISTS 1965; 16:204-7. [PMID: 5830714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Stratford J. The Queckenstedt Test and Lumbar Puncture. CANADIAN MEDICAL ASSOCIATION JOURNAL 1962; 86:1079. [PMID: 20327150 PMCID: PMC1849104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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