Enuresis.

The authors do not have all of the data about enuresis, and many children are subject to relapses or failure of treatment. There is no cause for despondency, however. Enuresis is no longer a mystery. Good data exist about the natural history, epidemiology, and etiology of enuresis. In addition, multiple treatment modalities are available to practitioners. This article has sought to review the scientific literature and to relate the authors' experience with enuresis. The authors recommend a treatment program for children with monosymptomatic nocturnal enuresis that includes removal of caffeine from the diet. Enuretic children do not consume enough fluid, and the authors recommend that the daily fluid requirement be divided during the day: 40% in the morning, 40% in the afternoon, and 20% in the evening, with no restriction of fluid. Normalization of small functional bladder capacities may help to cure enuresis and has an effect on the efficacy of other therapies. Treatment of enuretics with antibiotics is effective in children with UTI, bacteriuria, or cystitis cystica. DDAVP has been shown to be effective in the treatment of enuresis, especially in children who have achieved a normal functional bladder capacity. Bladder alarm systems also offer a potential cure of enuresis, are inexpensive, and show a low relapse rate.

Neonatal circumcision.

The merits of neonatal circumcision continue to be debated hotly. Some argue that circumcision is a "uniquely American medical enigma." Most of the world's male population remains uncircumcised; however, most boys born in the United States continue to undergo neonatal circumcision. Review of existing literature supports that most children who are uncircumcised do well from a medical standpoint and, thus, the question of whether US health care practitioners are subjecting neonates to an unnecessary surgical procedure remains. The medical benefits of circumcision are multiple, but most are small. The clearest medical benefit of circumcision is the relative reduction in the risk for a UTI, especially in early infancy. Although this risk [figure: see text] is real, the absolute numbers are small (risk ranges from 1 in 100 to 1 in 1000), and one investigator has estimated that it may take approximately 80 neonatal circumcisions to prevent one UTI. In the case of a patient with known urologic abnormalities that predispose to UTI, neonatal circumcision has a clearer role in terms of medical benefit to the patient. Most of the other medical benefits of circumcision probably can be realized without circumcision as long as access to clean water and proper penile hygiene are achieved. Proper penile hygiene should all but eliminate the risk for foreskin-related medical problems that will require circumcision. Moreover, proper hygiene and access to clean water has been shown to reduce the rate of development of squamous cell carcinoma of the penis in the uncircumcised population. Proper techniques on the care of the foreskin are illustrated in the American Academy of Pediatrics pamphlet titled "How to care for the uncircumcised penis." Regarding the relationship between STDs and circumcision, patient education and the practice of low-risk sexual behavior make a far greater impact than does routine circumcision in hopes of reducing the spread of HIV and other STDs. Nevertheless, in areas where safe sexual practices are poorly adhered to, circumcision can have a relative protective effect against the transmission of HIV and other STDs. The medical harms of circumcision lie mainly in the 1% acute complication rate and the additional patients who require revision of their initial circumcision for cosmetic or medical reasons. Anecdotally, the authors see far fewer complications in the acute and long-term phase when the circumcision has been performed by someone with expertise and experience with the procedure. Thus, the authors routinely recommend to parents that, if they choose to have their newborns circumcised, they should seek out an experienced practitioner. A negative psychologic and sexual impact of circumcision has been argued, but solid, scientific data are lacking. Special interest groups have argued that perhaps the greatest harm of circumcision is in performing an operation without a clear indication. Many of these groups have claimed that performing a routine neonatal circumcision is akin to performing a surgical procedure without a clear medical benefit, and in an infant, that is akin to surgery without informed consent. Although this is an extreme posture, the clinician can understand the emphasis on trying to provide invasive medical services only when a clear medical benefit is expected, especially when treating an infant or child. Deciding whether or not to circumcise an infant continues to challenge many new parents. Clearly, the procedure provides potential medical benefits and potential risks. It is difficult to say whether the benefits outweigh the risks for all male infants. Further complicating the decision for many American parents is that, in some areas of the United States, there exists an unexplained positive cultural connotation with neonatal circumcision. For these reasons, parents who actively choose to keep their sons uncircumcised need to be encouraged to make this decision forthrightly. Parents who choose to have their children circumcised also should be encouraged to actively seek an experienced practitioner who can afford the child adequate local analgesia.

Prototype system for enhancing cystometric analysis with special emphasis on the pediatric population.

BACKGROUND AND PURPOSE: A urodynamic test system of improved accuracy and reliability was developed and implemented for enhancing cystometry. This system integrates known medical information, including the specialized problems of pediatric urodynamics, with the cystometric and imaging data. METHODS: After the requirements for the ideal cystometrogram test unit were established, a system was constructed, calibrated, and implemented in clinical practice. The patient's age, size, and sex are used to produce a patient-specific pressure-volume template for the cystometrogram test. RESULTS: This template showed the minimal and normal bladder capacities and the physiologically safe, equivocal, and dangerous pressure fields coded with symbolic colors. Different time averages of the pressure data were used to show bladder factors such as compliance and instability. The templates with data were presented automatically (therefore objectively) without operator intervention on monitors during testing and as printed copies on completion. CONCLUSIONS: The presentation of data in an easily understood format facilitates effective communication between the urologist, referring physician, and patient. Some of the physiological and statistical problems in pediatric urodynamic testing are efficiently and accurately resolved by this system, resulting in better analysis and diagnostic capabilities.

Physiological-model-based derivation of the adult and child pharmacokinetic intraspecies uncertainty factors for volatile organic compounds.

The intraspecies uncertainty factor (UF(HH)=10x) is used in the determination of the reference dose or reference concentration and accounts for the pharmacokinetic and pharmacodynamic heterogeneity within the human population. The Food Quality Protection Act of 1996 mandated the use of an additional uncertainty factor (UF(HC)=10x) to take into account potential pre- and postnatal toxicity and lack of completeness of the data with respect to exposure and toxicity to children. There is no conclusive experimental or theoretical justification to support or refute the magnitude of the UF(HH) and UF(HC) nor any conclusive evidence to suggest that a factor of 100 is needed to account for intrahuman variability. This study presents a new chemical-specific method for estimating the pharmacokinetic (PK) component of the interspecies uncertainty factor (UF(HH-PK) and UF(HC-PK)) for volatile organic compounds (VOCs). The approach utilizes validated physiological-based pharmacokinetic (PBPK) models and simplified physiological-model-based algebraic equations to translate ambient exposure concentration to tissue dose in adults and children the ratio of which is the UF(HH-PK) and UF(HC-PK). The results suggest that: (i) the UF(HH-PK) and UF(HC-PK) are chemical specific; (ii) for the chemicals used in this study there is no significant difference between UF(HH-PK) and UF(HC-PK); (iii) the magnitude of UF(HH-PK) and UF(HC-PK) varies between 0.033 and 2.85 with respect to tissue and blood concentrations; (iv) the body weight, the rate of ventilation, the fraction of cardiac output flowing to the liver, the blood : air partition coefficient, and the hepatic extraction ratio are the only parameters that play a critical role in the variability of tissue and blood doses within species; and (v) the magnitude of the UF(HH-PK) and UF(HC-PK) obtained with the simplified steady-state equations is essentially the same with that obtained with PBPK models. Overall, this study suggests that no adult-children differences in the parent chemical concentrations of the VOCs are likely to be observed during inhalation exposures. The physiological-model-based approaches used in the present study to estimate the UF(HH-PK) and UF(HC-PK) provide a scientific basis for their magnitude. They can replace the currently used empirical default approaches to provide chemical-specific UF(HH-PK) in future risk assessments.

Physician-based case-control study of non-melanoma skin cancer in Baytown, Texas.

A physician-based case-control study of non-melanoma skin cancer was conducted to test the hypothesis that employment in the petroleum industry increased the risk of basal cell carcinoma (BCC), squamous cell carcinoma (SCC), or both (BCC+SCC). Other potential risk factors were also investigated. There were 174 cases of BCC, 59 cases of SCC, 72 cases of both and 229 controls completing a self-administered questionnaire. The most important risk factors common to all skin cancer categories were a family history of skin cancer and time spent outdoors. Employment in the petroleum industry showed a slight association with BCC+SCC, but only in the multivariate model. Further study is needed to evaluate whether this association is causal, or due to chance, bias or confounding.

An evaluation of scheduled bright light and darkness on rotating shiftworkers: trial and limitations.

The effectiveness of a program of scheduled bright light and dark to alter the circadian pacemakers of rotating shiftworkers were evaluated. Thirteen industrial workers were exposed to scheduled bright light of 6,000-12,000 lux on at least half of their 12-hr night shifts for 3 months, as well as ambient light of 1,200-1,500 lux. All 10 workers evaluated with urinary melatonin levels had morning melatonin suppression on the night shift, and 50% had a statistically significant circadian change. Although a few significant changes were noted concerning reported sleep and alertness, most findings concerning self-perceived alertness and performance at work, and sleep patterns were mixed and inconsistent. The major complaint was increased difficulty adjusting to being off work after the night shift during the light phase. The alteration in urinary melatonin levels is the first objective demonstration that the bright light technology can alter the circadian pacemakers of workers in an industrial setting. At this worksite, a number of interventions to lessen the effects of rotating shiftwork are being evaluated. Criteria are proposed that should be considered in evaluating a worksite for the use of bright light technology.

Sleep and alertness in a 12-hour rotating shift work environment.

Industrial workers on rotating shifts were evaluated for the effects of rotating shift work. Twenty-five (86%) of 29 workers in the study area who work 12-hour shifts in a scheduled 16-day rotation participated. The mean number of hours of sleep at home after working day shifts (5.6 hours) was less than after the first three night shifts (6.0, 6.4, and 6.6 hours, respectively). At work, the mean number of hours at reported peak alertness was greater during the night shift (6.1 hours) than the day shift (4.9 hours), but the perceived alertness levels were relatively lower on the night shift. Increased perceived difficulty working and decreased perceived productivity and safety were reported on the first night of the night shift. We demonstrate that workers on rotating shift work exhibit low alertness-related outcomes on both shifts. These workers have early shift work starting times that appear to disrupt sleep patterns on both day and night shifts. At this work site, a number of interventions to lessen the effects of rotating shift work are being evaluated.

Colorectal cancer incidence among polypropylene manufacturing workers. An update.

This study updates an earlier investigation that found a sixfold excess incidence of colorectal cancer among polypropylene workers for the period January 1960 to September 1985. The study cohort comprised 412 male workers with at least 6 months employment and 10 years latency. For the extended follow-up period (October 1985 to May 1992), the standardized incidence ratio (SIR) based on state comparison rates was slightly elevated and not statistically significant (SIR = 1.5, 95% confidence interval [CI] = 0.5 to 3.5). A 2.3-fold excess was observed among process workers (95% CI = 0.3 to 8.2), but this was based on only two cases. Risk among process/mechanical workers was greater for short-term workers (< 10 years, SIR = 3.2, 95% CI = 0.7 to 9.2) compared with longer-term workers (> or = 10 years, SIR = 0.7, 95% CI = 0.02 to 4.0). Overall, the update findings do not suggest an occupationally related risk. Possible influences of company-sponsored colorectal cancer screening, the polyolefin unit shutdown, and other factors are discussed.

Colorectal polyp incidence among polypropylene manufacturing workers.

To follow up earlier findings of increased colorectal cancer and polyp risk among a group of Texas polypropylene manufacturing workers, a second company-sponsored colorectal cancer screening program was conducted. Ninety-four (64%) of the 147 male workers negative for polyps in the first screening were rescreened. Age- and examiner-adjusted incidence rate ratios (IRRs) were modestly elevated for polypropylene manufacturing workers compared with patients screened at the same clinic for total (IRR = 1.31; 90% confidence interval [CI] = 0.84 to 2.03) and adenomatous (IRR = 1.80; 90% CI = 0.68 to 4.78) polyps. However, risk of adenomas among the highest exposed group (early term process/mechanical workers: IRR = 1.77; 90% CI = 0.51 to 6.18) was similar to risk in the least-exposed group (engineer/chemist/administrative workers: IRR = 2.02; 90% CI = 0.56 to 7.31). The modest, nonsignificant excesses and the similarity in risk across job categories does not suggest an occupationally related risk, although small numbers and potential biases preclude making definitive conclusions.

Material safety data sheets. Caveat emptor.

Numerous hazardous chemicals are present in workplaces and the environment. Physicians are likely to be increasingly challenged with the evaluation of individuals exposed to these chemicals. Recent legislation mandates the creation of material safety data sheets that describe the composition and toxicity of hazardous compounds. This legislation has also greatly increased the availability of material safety data sheets to workers and physicians. While these can be of great assistance in the evaluation of exposed individuals, they often contain deficiencies that preclude the prudent physician from relying exclusively on them. A few typical material safety data sheets are reviewed to illustrate what one can expect to find.