76
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Pittilo RM, Clarke JM, Harris D, Mackie IJ, Rowles PM, Machin SJ, Woolf N. Cigarette smoking and platelet adhesion. Br J Haematol 1984; 58:627-32. [PMID: 6440587 DOI: 10.1111/j.1365-2141.1984.tb06109.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Non-abraded rabbit endothelium has been exposed to human blood taken from male non-smoking volunteers before and after the smoking of two medium tar cigarettes, in an in vitro system using a Baumgartner chamber. In each case the blood was allowed to circulate for 10 min at a constant flow rate. Blood from 10 volunteers has been tested in this way. Scanning electron microscopy of the endothelial surfaces demonstrates large numbers of adherent platelets when 'post-smoking blood' is used, but very few and in some cases none with the 'pre-smoking' blood. As a further control to ensure that this phenomenon did not occur as a result from changes in the vessel related to the time during which it had been removed from its normal physiological environment, blood from further non-smoking volunteers was passed over seven of the remaining pieces of vessel at the completion of these runs. Platelets were either absent or very few in number, as with the pre-smoking samples.
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77
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Nicholson LJ, Clarke JM, Pittilo RM, Machin SJ, Woolf N. The mesothelial cell as a non-thrombogenic surface. Thromb Haemost 1984; 52:102-4. [PMID: 6523428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A technique for harvesting mesothelial cells is described. This entails collagenase digestion of omentum after which the cells can be cultured. The technique has been developed using the rat, but has also been successfully applied to human tissue. Cultured rat mesothelial cells obtained in this way have been examined by scanning electron microscopy. Rat mesothelial cells grown on plastic film have been exposed to blood in an in vitro system using a Baumgartner chamber and have been demonstrated to support blood flow. No adhering platelets were observed on the mesothelial cell surface. Fibroblasts similarly exposed to blood as a control were washed off the plastic.
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78
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McInnes GT, Harrison IR, Shelton JR, Perkins RM, Clarke JM. Relative potency of prorenoate potassium and spironolactone in attenuating diuretic induced hypokalaemia. Br J Clin Pharmacol 1984; 18:169-74. [PMID: 6487456 PMCID: PMC1463509 DOI: 10.1111/j.1365-2125.1984.tb02449.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The plasma potassium responses to the aldosterone antagonists prorenoate K (10 mg/day and 40 mg/day) and spironolactone (25 mg/day and 100 mg/day) were compared following treatment for 11 days in combination with the diuretic metolazone (2.5 mg/day) in a double-blind crossover study in twelve healthy men. The best estimate of the potency of prorenoate K relative to spironolactone in attenuating metolazone induced hypokalaemia was 5.6 with 95% confidence limits 2.4-35.2. The method employed allowed a statistically valid quantitative comparison of the potassium sparing properties of the mineralocorticoid antagonists after repeated doses and may be useful in the preclinical evaluation of these drugs.
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79
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Clarke JM, Pittilo RM, Nicholson LJ, Woolf N, Marston A. Seeding Dacron arterial prostheses with peritoneal mesothelial cells: a preliminary morphological study. Br J Surg 1984; 71:492-4. [PMID: 6234046 DOI: 10.1002/bjs.1800710704] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A preliminary laboratory study has been undertaken using dogs, in which porous Dacron arterial prostheses have been seeded with autologous peritoneal mesothelial cells before implantation into the arterial system. These cells were harvested from omentum by collagenase digestion and were introduced into the graft at the time of preclotting. Examination of the grafts by scanning and transmission electron microscopy one month after insertion showed no organized cellular lining in the control graft. In three seeded grafts there was a lining of mesothelial cells which extended over the whole surface of the grafts up to 1 cm from the suture lines. Selected areas of the grafts have been analysed morphometrically. In the seeded grafts there is a cellular layer which on average covers 94 per cent of the luminal surface. These results suggest that mesothelial cells, which both secrete prostacyclin and possess fibrinolytic activity, present a possible alternative to endothelium as a cellular lining for prosthetic grafts.
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80
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Clarke JM. Dysphagia with Angelchik prosthesis. Ann Thorac Surg 1984; 37:355. [PMID: 6712337 DOI: 10.1016/s0003-4975(10)60746-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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81
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Clarke JM, Pittilo RM, Machin SJ, Woolf N. A study of the possible role of mesothelium as a surface for flowing blood. Thromb Haemost 1984; 51:57-60. [PMID: 6547010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Abstract
Mouse mesothelium has been examined as a surface for supporting blood flow. We have examined ten pieces of intact mesothelium and ten pieces of damaged mesothelium following 10 min exposure to flowing blood in a Baumgartner chamber. Scanning electron microscopy of the intact specimens demonstrated no adhering blood platelets, whereas the damaged specimens were found to be covered with large numbers of adhering platelets. In addition we have demonstrated that undamaged mesothelium does not appear to be morphologically altered after exposure to blood, and that undamaged mesothelium produces significantly more prostacyclin than damaged control. These findings support that mesothelial cells hold promise as a lining for prosthetic vascular implants.
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82
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McInnes GT, Shelton JR, Perkins RM, Harrison IR, Clarke JM. Use of a bioassay in healthy men to evaluate diuretic-spironolactone combinations. Br J Clin Pharmacol 1983; 15:564-6. [PMID: 6860532 PMCID: PMC1427727 DOI: 10.1111/j.1365-2125.1983.tb02092.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The plasma potassium responses to 1 week's treatment with metolazone 0.625 mg, 1.25 mg and 2.5 mg in combination with spironolactone 50 mg, and metolazone 2.5 alone were examined in a double-blind, crossover study in twelve healthy subjects. Spironolactone attenuated the hypokalaemia induced by metolazone--addition of spironolactone 50 mg to metolazone 2.5 mg raised plasma potassium by 0.18 mmol/l (P less than 0.025). In the presence of spironolactone, a linear log metolazone dose-plasma potassium response relationship (P less than 0.01) was demonstrated. Spironolactone was unable to compensate fully for metolazone's hypokalaemic effect although in combination with metolazone 0.625 mg and 1.25 mg, plasma potassium concentration was maintained close to pretreatment levels. The human bioassay employed provided conveniently quantitative information which allows the rational development of a fixed dose diuretic-spironolactone combination tablet.
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83
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McInnes GT, Clarke JM, Shelton JR. Dose-response relationships for spironolactone in combination with a potassium-wasting diuretic. Clin Pharmacol Ther 1983; 33:35-43. [PMID: 6848297 DOI: 10.1038/clpt.1983.5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The plasma and urine electrolyte responses to repeated doses of spironolactone, 25, 50, and 100 mg, in combination with metolazone, 2.5, 5.0, and 10 mg, were examined in 18 healthy subjects (six at each dose of metolazone). During the period of pharmacologic steady state, there were log linear spironolactone dose-response relationships for plasma potassium, sodium, and bicarbonate (P less than 0.001 in each case) with no contraindication to parallelism between the metolazone groups. In the absence of mineralocorticoid challenge, spironolactone dose-urine electrolyte responses could not be demonstrated. However, after fludrocortisone, spironolactone log dose-response trends were linear with respect to natriuresis (P = 0.027), antikaliuresis (P = 0.020), and log 10 Na/K (P = 0.001), which is usually considered the best single index of renal antimineralocorticoid activity, and exhibited parallelism between the metolazone doses. These observations suggest that a convenient bioassay for aldosterone antagonists in normal men may be provided by the electrolyte responses to repeated doses of such drugs in combination with potassium-wasting diuretics. In view of the limitations of other methods, this approach may have particular relevance to the evaluation of potassium-sparing properties.
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84
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Clarke JM. Surgery in Jehovah's witnesses. Br J Hosp Med (Lond) 1982; 27:497-500. [PMID: 7046869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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85
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McInnes GT, Shelton JR, Ramsay LE, Harrison IR, Asbury MJ, Clarke JM, Perkins RM, Venning GR. Relative potency and structure activity relationships of aldosterone antagonists in healthy man: correlation with animal experience. Br J Clin Pharmacol 1982; 13:331-9. [PMID: 6460516 PMCID: PMC1402118 DOI: 10.1111/j.1365-2125.1982.tb01383.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
1 The renal antimineralocorticoid potency of single doses of thirteen compounds with properties in animals compatible with competitive aldosterone antagonism was compared to that of spironolactone in healthy men. 2 Twelve compounds showed significant activity when compared to placebo but only one, prorenoate potassium, was significantly more potent than spironolactone on a weight basis. 3 The results allowed ranking of the compounds in order of potency relative to spironolactone and general observations on structure activity relationships in man. 4 Animal bioassays and in vitro aldosterone binding studies are unreliable predictors of the human activity of competitive mineralocorticoid antagonists.
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86
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McInnes GT, Shelton JR, Asbury MJ, Harrison IR, Clarke JM, Ramsay LE, Venning GR. Bioassay of a new aldosterone antagonist and evaluation of a simple method of quantitative comparison. Clin Pharmacol Ther 1981; 30:218-25. [PMID: 7249505 DOI: 10.1038/clpt.1981.151] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The renal antimineralocorticoid activity of single oral doses of a new aldosterone antagonist OH OPC(ME)-K was compared to that of spironolactone in two studies in healthy men. OH OPC(ME)-K reversed the urinary electrolyte response to fludrocortisone in the period up to 16 hr after treatment, but it was less potent than spironolactone on a weight basis. The best estimate of the relative potency of OH OPC(ME)-K: spironolactone (derived from a simple protocol using equal single doses of the two drugs) was 0.60:1 (95% confidence limits 0.24:1 to 1.42:1), in good agreement with the estimate from a more complex three-dose parallel-line bioassay (0.61:1, 95% confidence limits 0.48:1 to 0.79:1). The results of simple single-dose studies can be used, with certain assumptions, to provide a useful estimate of the relative potency of new aldosterone antagonists at an early stage of development.
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87
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McInnes GT, Asbury MJ, Shelton JR, Harrison IR, Ramsay LE, Venning GR, Clarke JM. The active constituent of spironolactone after acute administration in man [proceedings]. Br J Clin Pharmacol 1980; 9:295P-296P. [PMID: 7362751 DOI: 10.1111/j.1365-2125.1980.tb04854.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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88
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McInnes GT, Asbury MJ, Shelton JR, Harrison IR, Ramsay LE, Venning GR, Clarke JM. Activity of sulfur-containing intermediate metabolites of spironolactone. Clin Pharmacol Ther 1980; 27:363-9. [PMID: 7357793 DOI: 10.1038/clpt.1980.48] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The renal antimineralocorticoid activity of single administration of 2 sulfur-containing compounds, which are thought to be intermediate metabolites of spironolactone, was assessed in healthy subjects. They were each active in reversing the urinary electrolyte changes indiced by fludrocortisone for 2 to 10 hr after dosing, but only the 7 alpha-thiomethyl derivative exhibited activity in the period 12 to 16 hr after treatment. The activity of both drugs was less than of spironolactone. Taking urinary log 10 Na/K as the best index of antimineralocorticoid activity, the potencies of the intermediates relative to spironolactone were 0.26 (95% confidence limits, 0.12 to 0.49) for 7 alpha-thio-spirolactone and 0.33 (95% confidence limits, 0.15 to 0.62) for 7 alpha-thiomethyl-spirolactone in the period 2 to 10 hr after medication. We conclude that these minor sulfur-containing intermediate metabolites of spironolactone are unlikely to contribute significantly to the renal antimineralocorticoid activity of spironolactone.
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89
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Rogers DW, Clarke JM, Cupidore L, Ramlal AM, Sparke BR, Serjeant GR. Early deaths in Jamaican children with sickle cell disease. BRITISH MEDICAL JOURNAL 1978; 1:1515-6. [PMID: 656779 PMCID: PMC1605039 DOI: 10.1136/bmj.1.6126.1515] [Citation(s) in RCA: 121] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In Jamaican children with homozygous sickle cell (SS) disease diagnosed at birth two-year survival was 87%, compared with 95% in children with sickle cell-haemoglobin C (CS) disease, and 99% in normal controls. Death among those with SS disease occurred most often between the ages of 6 and 12 months. Principal causes were acute splenic sequestration and pneumococcal infection. Neonatal diagnosis of haemoglobinopathies must be followed by close observation if mortality is to be reduced by early diagnosis and treatment of these complications.
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90
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Clarke JM, Ramsay LE, Shelton JR, Tidd MJ, Murray S, Palmer RF. Factors influencing comparative bioavailability of spironolactone tablets. J Pharm Sci 1977; 66:1429-32. [PMID: 579186 DOI: 10.1002/jps.2600661020] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The bioavailability of spironolactone from 10 tablet formulations, selected to provide a wide range of specifications and in vitro dissolution rates, was assessed from the plasma and urinary levels of its major unconjugated metabolite, canrenone, in a study of balanced incomplete block design using 11 healthy subjects. Significant but weak correlations existed between the amount of spironolactone in solution at 40 min in vitro and the area under the plasma concentration-time curve for canrenone and urinary canrenone excretion. The correlations between in vitro dissolution and bioavailability parameters appeared to be weakened by two tablet formulations, one with dibasic calcium phosphate as the principal excipient and the other formulated from micronized spironolactone bulk drug. Measurement of in vitro dissolution of spironolactone tablets is of value for quality control purposes, provided no major alteration is made in the formulation.
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91
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Abstract
The 24-hour cardiac rhythm was studied in 86 subjects (41 male, 45 female) aged 16-65 years, after exclusion of 15 additional volunteers with suspected abnormalities. The electrocardiogram was recorded continuously for two 24-hour periods. In this apparently normal population, 10 subjects (12%) had disturbances of rhythm which are widely believed to be of serious prognostic significance; they included frequent ventricular ectopic beats, R-on-T and multifocal ventricular ectopic beats, bigeminy, and ventricular tachycardia. Supraventricular tachycardia, infrequent ventricular ectopic beats, junctional rhythm, and second-degree heart block were also observed, and if these are included most of the subjects showed some disturbance of rhythm. Bradyarrhythmias and tachyarrhythmias were equally common in waking hours and during sleep. These disturbances were not confined to the older age-groups. Heart-rate but not the number of arrhythmias was significantly higher in smokers.
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92
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Clarke JM, Hamer NA, Shelton JR, Taylor S, Venning GR. Proceedings: Rhythm of normal human heart. Heart 1976; 38:882. [PMID: 973931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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93
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Serjeant BE, Clarke JM, Desai P, Serjeant GR. A simple micromethod for the measurement of fetal haemoglobin. J Clin Pathol 1975; 28:761-4. [PMID: 1165322 PMCID: PMC475849 DOI: 10.1136/jcp.28.9.761] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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94
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Thomas HF, Clarke JM, Rayl JE, Woodward ER. Results of the combined fundic patch-fundoplication operation in the treatment of reflux esophagitis with stricture. SURGERY, GYNECOLOGY & OBSTETRICS 1972; 135:241-5. [PMID: 5049948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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95
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96
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Clarke JM. Culdocentesis in the evaluation of blunt abdominal trauma. SURGERY, GYNECOLOGY & OBSTETRICS 1969; 129:809-10. [PMID: 5821238] [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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97
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Clarke JM, Talbert JL. Neoplastic cysts of the spleen in children. Am Surg 1969; 35:488-91. [PMID: 5785912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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98
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Clarke JM, Rayl JE, Woodward ER. Experience with the Thal and Nissen operations in the treatment of reflux esophagitis with stricture. REVIEW OF SURGERY 1969; 26:212-3. [PMID: 5792098] [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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99
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100
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Clarke JM, Rayl JE, Woodward ER. Experience with the Thal and Nissen operations in the treatment of reflux esophagitis with stricture: a preliminary report. Am Surg 1969; 35:89-94. [PMID: 5763784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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