been excluded (e.g., because of death) during the interval between the original survey and the extended survey. Another possibility is that exposure to hair dyes may increase the frequency of other cancers with a shorter latent period, thus decreasing the chance of inclusion in a casecontrol study of bladder cancer. However, we agree with lain and colleagues that exposure to hair dye does not seem to result in an appreciable frequency of bladder cancer, but that the possibility that hair dye is a carcinogen either alone or synergistically cannot be ruled out. C.I. NEUTEL, PH
R.C. N.uR, M STAT, PH D J.M. LAST, MD
Department of epidemiology and community medicine University of Ottawa Ottawa, Ont.
Reference 1. MILLER CT, NEUTEL CI, NAIR RC,
et al: Relative importance of risk factors in bladder carcinogenesis. J Chronic Dis 31: 51, 1978
Change in design of life preservers may save lives To the editor: The recent drownings of 12 boys and an instructor from St. John's School in Claremont, Ont. in the cold waters of Lake Timiskaming prompted this letter. For many years I have wondered about the mechanism of drownings in which the victims wore life preservers. According to the newspapers in Colorado, the Canadian victims were all wearing life preservers when found. It seems that this should have prevented drowning by suffocation or swallowing of water. The possibility of death from exposure cannot be ruled out, but I recall many similar deaths of allied servicemen in the South Pacific in World War II, when the water and air temperatures were acceptable. I wonder if the cause of many of these deaths may be diaphragmatic and intercostal exhaustion, contributed to by the design of the life preserver. Ordinarily, if one breathes in, for example, 3 L of air, 3 L of air is displaced outwards from the body; the work involved is minimal. However, if a person is immersed in water to about the middle of the chest, inhalation of 3 L of air causes the outward displacement of 3 L of
were also reinfected with a new organism; one child had radiologically demonstrated vesicoureteric reflux and recurrent infection with the same organism. Therefore, as I see the data, 29 of 30 lower urinary tract infections were cured with a single dose of TMP-SMX. The only failure was, in fact, in a child with an underlying radiologic defect. This compares with the recent data by Fang, TolkoffRubin and Rubin.1 Using antibody coating of bacteria to distinguish upper from lower urinary tract infection, they found 100% success of single-dose therapy with amoxicillin SOLOMON GARB, MD American Medical Center in 43 patients with lower urinary Cancer Research Center and Hospital tract infection. Lakewood, Colorado Bailey and Abbott conclude by stating that "single-dose therapy for uncomplicated urinary tract infecTreatment of urinary tract tions has proved simple . . .". The infection with a single dose vague word uncomplicated fails to of trimethoprim-sulfamethoxazole make its mark. The diagnostic alterTo the editor: The recent article by natives are presumed lower or upper Drs. Ross R. Bailey and George D. urinary tract infection (a clinical deAbbott (Can Med Assoc J 118: cision). The suggested therapeutic re551, 1978) reports only 85% sponse is single-dose therapy for pasuccess in 60 cases of urinary tients with lower urinary tract infectract infection treated with a single tion and conventional therapy for dose of trimethoprim-sulfamethoxa- those with upper urinary tract infeczole (TMP-SMX). Their patients tion. Recurrent infection in women included 40 women, 3 of whom are and probably all infections in chillisted as having acute pyelonephritis dren should be further investigated. (in their Table I). .All three received J. ZEVI SHAINHOUSE, MD, B sc a conventional course of therapy. Fellow, infectious diseases Given the authors' statement that Stanford University Palo Alto, California "this approach [single-dose therapy] ... is not recommended if the patient is severely ill with acute pyelonephritis", I assume that these three Reference women were, in fact, not random- 1. F.io LST, TOLKOFF-RUBIN NE, RuBIN RH: Efficacy of single-dose ized and should not have been inand conventional amoxicillin therapy cluded in their study. Their use of in urinary-tract infection localized by the words severely ill suggests that the antibody-coated bacteria technic. N Engi J Med 298: 413, 1978 persons with mild acute pyelonephritis might be considered for single-dose therapy. This is certainly not justified by the results of this To the editor: We have several comments to make in answer to Dr. paper. In effect, all persons receiving Shainhouse's letter. In our study any woman with a single-dose therapy had only lower urinary tract infection - asympto- urinary tract infection that was pomatic or symptomatic. In 3 of the tentially treatable by orally admin20 women single-dose therapy was istered antimicrobial therapy was insaid to have failed, but all were con- cluded. It was fortuitous that the sidered to have a reinfection with a three women with clinical acute pyenew organism (in contrast to recur- lonephritis were randomly allocated rent infection with the same organ- to receive a 5-day course of treatism) and therefore therapy should ment. No children with presumed not be considered to have failed. pyelonephritis were included in the Similarly, two of the three children study. We would not currently recin whom single-dose therapy failed ommend that patients with presumed
water, a substantial amount of work. Ordinary life preservers suspend a person vertically, with the diaphragm below water. I have tested this concept by standing motionless in water up to the middle of my chest; after about 10 minutes, breathing became difficult. In contrast, when I floated on my back with part of the diaphragm above water, breathing was no problem. If there is any validity in these notions, a simple improvement in the design of life preservers - for example, a second buoyant element under the feet to permit horizontal floating - could help save lives.
308 CMA JOURNAL/AUGUST 26, 1978/VOL. 119
R.C. N.uR, M STAT, PH D J.M. LAST, MD
Department of epidemiology and community medicine University of Ottawa Ottawa, Ont.
Reference 1. MILLER CT, NEUTEL CI, NAIR RC,
et al: Relative importance of risk factors in bladder carcinogenesis. J Chronic Dis 31: 51, 1978
Change in design of life preservers may save lives To the editor: The recent drownings of 12 boys and an instructor from St. John's School in Claremont, Ont. in the cold waters of Lake Timiskaming prompted this letter. For many years I have wondered about the mechanism of drownings in which the victims wore life preservers. According to the newspapers in Colorado, the Canadian victims were all wearing life preservers when found. It seems that this should have prevented drowning by suffocation or swallowing of water. The possibility of death from exposure cannot be ruled out, but I recall many similar deaths of allied servicemen in the South Pacific in World War II, when the water and air temperatures were acceptable. I wonder if the cause of many of these deaths may be diaphragmatic and intercostal exhaustion, contributed to by the design of the life preserver. Ordinarily, if one breathes in, for example, 3 L of air, 3 L of air is displaced outwards from the body; the work involved is minimal. However, if a person is immersed in water to about the middle of the chest, inhalation of 3 L of air causes the outward displacement of 3 L of
were also reinfected with a new organism; one child had radiologically demonstrated vesicoureteric reflux and recurrent infection with the same organism. Therefore, as I see the data, 29 of 30 lower urinary tract infections were cured with a single dose of TMP-SMX. The only failure was, in fact, in a child with an underlying radiologic defect. This compares with the recent data by Fang, TolkoffRubin and Rubin.1 Using antibody coating of bacteria to distinguish upper from lower urinary tract infection, they found 100% success of single-dose therapy with amoxicillin SOLOMON GARB, MD American Medical Center in 43 patients with lower urinary Cancer Research Center and Hospital tract infection. Lakewood, Colorado Bailey and Abbott conclude by stating that "single-dose therapy for uncomplicated urinary tract infecTreatment of urinary tract tions has proved simple . . .". The infection with a single dose vague word uncomplicated fails to of trimethoprim-sulfamethoxazole make its mark. The diagnostic alterTo the editor: The recent article by natives are presumed lower or upper Drs. Ross R. Bailey and George D. urinary tract infection (a clinical deAbbott (Can Med Assoc J 118: cision). The suggested therapeutic re551, 1978) reports only 85% sponse is single-dose therapy for pasuccess in 60 cases of urinary tients with lower urinary tract infectract infection treated with a single tion and conventional therapy for dose of trimethoprim-sulfamethoxa- those with upper urinary tract infeczole (TMP-SMX). Their patients tion. Recurrent infection in women included 40 women, 3 of whom are and probably all infections in chillisted as having acute pyelonephritis dren should be further investigated. (in their Table I). .All three received J. ZEVI SHAINHOUSE, MD, B sc a conventional course of therapy. Fellow, infectious diseases Given the authors' statement that Stanford University Palo Alto, California "this approach [single-dose therapy] ... is not recommended if the patient is severely ill with acute pyelonephritis", I assume that these three Reference women were, in fact, not random- 1. F.io LST, TOLKOFF-RUBIN NE, RuBIN RH: Efficacy of single-dose ized and should not have been inand conventional amoxicillin therapy cluded in their study. Their use of in urinary-tract infection localized by the words severely ill suggests that the antibody-coated bacteria technic. N Engi J Med 298: 413, 1978 persons with mild acute pyelonephritis might be considered for single-dose therapy. This is certainly not justified by the results of this To the editor: We have several comments to make in answer to Dr. paper. In effect, all persons receiving Shainhouse's letter. In our study any woman with a single-dose therapy had only lower urinary tract infection - asympto- urinary tract infection that was pomatic or symptomatic. In 3 of the tentially treatable by orally admin20 women single-dose therapy was istered antimicrobial therapy was insaid to have failed, but all were con- cluded. It was fortuitous that the sidered to have a reinfection with a three women with clinical acute pyenew organism (in contrast to recur- lonephritis were randomly allocated rent infection with the same organ- to receive a 5-day course of treatism) and therefore therapy should ment. No children with presumed not be considered to have failed. pyelonephritis were included in the Similarly, two of the three children study. We would not currently recin whom single-dose therapy failed ommend that patients with presumed
water, a substantial amount of work. Ordinary life preservers suspend a person vertically, with the diaphragm below water. I have tested this concept by standing motionless in water up to the middle of my chest; after about 10 minutes, breathing became difficult. In contrast, when I floated on my back with part of the diaphragm above water, breathing was no problem. If there is any validity in these notions, a simple improvement in the design of life preservers - for example, a second buoyant element under the feet to permit horizontal floating - could help save lives.
308 CMA JOURNAL/AUGUST 26, 1978/VOL. 119
