Influence of Residency Training on Operative Vaginal Delivery in Independent Practice

OBJECTIVE

To determine if residency training in the use of forceps and vacuums in vaginal deliveries is associated with their use in postgraduate practice.

STUDY DESIGN

We surveyed all Ob/Gyn residency graduates of 4 academic programs from 2004-2012. The average number of vacuums and forceps performed per graduating resident was linked to respondents, who were then grouped by self-report as using forceps alone, vacuums alone, or both in practice. Multivariable logistic regression determined predictors of use of forceps and vacuums in practice

RESULTS

The response rate was 61.2% (n=200). Those practicing obstetrics (n=171) were classified as forceps only (24%), vacuums only (22%), or both (54%). Use of forceps in practice was greater for those who graduated within the last 5 years (OR 7.55, 95% CI 2.37-24.07), felt inadequately trained in vacuums (OR 4.58, 95% CI 1.23-17.00), cared for a patient population <50% privately insured (OR 4.08, 95% CI 1.58-10.52), and performed more forceps in residency (OR 1.69, 95% CI 1.31-2.18 per 5 forceps performed on average). The only significant predictor of vacuum use was the number of vacuum deliveries performed in residency (OR 3.71, 95% CI 2.28-6.01 per 5 vacuums performed on average).

CONCLUSION

Independent practice pattern for operative vaginal delivery reflects residency training for both vacuums and forceps.

Can Fetal Limb Soft Tissue Measurements in the Third Trimester Predict Neonatal Adiposity?

OBJECTIVES

Neonatal adiposity is associated with chronic metabolic sequelae such as diabetes and obesity. Identifying fetuses at risk for excess neonatal body fat may lead to research aimed at limiting nutritional excess in the prenatal period. We sought to determine whether fetal arm and leg soft tissue measurements at 28 weeks' gestation were predictive of neonatal percent body fat METHODS : In this prospective observational cohort study of singleton term pregnancies, we performed sonography at 28 and 36 weeks' gestation, including soft tissue measurements of the fetal arm and thigh (fractional limb volume and cross-sectional area). We estimated the neonatal body composition (percent body fat) using anthropometric measurements and air displacement plethysmography. We estimated Spearman correlations between sonographic findings and percent body fat and performed modeling to predict neonatal percent body fat using maternal characteristics and sonographic findings.

RESULTS

Our analysis of 44 women yielded a mean maternal age of 30 years, body mass index of 26 kg/m(2), and birth weight of 3382 g. Mean neonatal percent body fat was 8.1% by skin folds at birth and 12.2% by air displacement plethysmography 2 weeks after birth. Fractional thigh volume measurements at 28 weeks yielded the most accurate model for predicting neonatal percent body fat (R(2) = 0.697; P = .001), outperforming models that used abdominal circumference (R(2)= 0.516) and estimated fetal weight (R(2)= 0.489).

CONCLUSIONS

Soft tissue measurements of the fetal thigh at 28 weeks correlated better with neonatal percent body fat than currently used sonographic measurements. After validation in a larger cohort, our models may be useful for prenatal intervention strategies aimed at the prevention of excess fetal fat accretion and, potentially, optimization of long-term metabolic health.

Does the number of forceps deliveries performed in residency predict use in practice?

OBJECTIVE

We aimed to determine whether a threshold number of forceps deliveries in residency predicts use of forceps in independent practice.

STUDY DESIGN

We surveyed obstetrics and gynecology residency graduates of 2 academic programs from 2008 through 2012 regarding the use of operative vaginal delivery in practice. At these programs, residents are trained in both forceps and vacuums. Individual case log data were obtained with the number of forceps deliveries performed by each respondent during residency. Respondents were grouped as currently using any forceps or vacuums alone. A logistic regression model estimated the probability of forceps use, predicted by the number of residency forceps deliveries. From the resulting receiver-operating characteristic curve, we assessed sensitivity, specificity, positive predictive value, and area under the curve.

RESULTS

The response rate was 85% (n = 58) and 90% (n = 52) practice obstetrics. Seventy-nine percent (n = 41) use forceps in practice. The mean number of forceps performed during residency was 22.3 ± 1.3 (mean ± SE) in the any-forceps group and 18.5 ± 2.1 in the vacuums-only group (P = .14). Although the model performed only moderately (area under the curve, 0.61, 95% confidence interval [CI], 0.42-0.81), more than 13 residency forceps deliveries corresponded to a 95% sensitivity (95% CI, 84-99) and a positive predictive value of 83% (95% CI, 69-92) for using forceps in practice. The specificity of this threshold is 27% (95% CI, 6-61).

CONCLUSION

Although exceeding 13 forceps deliveries made it highly likely that obstetricians would use them in practice, further study is necessary to set goals for a number of resident forceps deliveries that translate into use in practice.

Baseline placental growth factor levels for the prediction of benefit from early aspirin prophylaxis for preeclampsia prevention

OBJECTIVE

Placental growth factor (PlGF) levels early in pregnancy are lower in women who ultimately develop preeclampsia. Early initiation of low-dose aspirin reduces preeclampsia risk in some high risk women. We hypothesized that low PlGF levels may identify women at increased risk for preeclampsia who would benefit from aspirin.

STUDY DESIGN

Secondary analysis of the MFMU High-Risk Aspirin study including singleton pregnancies randomized to aspirin 60mg/d (n=102) or placebo (n=72), with PlGF collected at 13w 0d-16w 6d. Within the placebo group, we estimated the probability of preeclampsia by PlGF level using logistic regression analysis, then determined a potential PlGF threshold for preeclampsia prediction using ROC analysis. We performed logistic regression modeling for potential confounders.

RESULTS

ROC analysis indicated 87.71pg/ml as the threshold between high and low PlGF for preeclampsia-prediction. Within the placebo group high PlGF weakly predicted preeclampsia (AUC 0.653, sensitivity/specificity 63%/66%). We noted a 2.6-fold reduction in preeclampsia with aspirin in the high-PlGF group (12.15% aspirin vs 32.14% placebo, p=0.057), but no significant differences in preeclampsia in the low PlGF group (21.74% vs 15.91%, p=0.445).

CONCLUSIONS

Unlike other studies, we found that high rather than low PlGF levels were associated with an increased preeclampsia risk. Low PlGF neither identified women at increased risk of preeclampsia nor women who benefitted from aspirin. Further research is needed to determine whether aspirin is beneficial in women with high PlGF, and whether the paradigm linking low PlGF and preeclampsia needs to be reevaluated.

CONDENSATION

High-risk women with low baseline PlGF, a risk factor for preeclampsia, did not benefit from early initiation of low-dose aspirin.

Fetal weight estimation in diabetic pregnancies using the gestation-adjusted projection method: comparison of two timing strategies for third-trimester sonography

OBJECTIVES

The gestation-adjusted projection method extrapolates birth weight using third-trimester sonography. This technique is shown to be more accurate for sonographic examinations from 34 weeks to 36 weeks 6 days than 37 weeks to 38 weeks 6 days. Our objective was to determine whether even earlier sonographic examinations (31 weeks-33 weeks 6 days) further improves birth weight prediction in patients with diabetes.

METHODS

We conducted a retrospective cohort analysis of 388 pregnant women with pregestational or gestational diabetes who delivered at 37 weeks or later and had a sonographic examination performed between 31 weeks and 36 weeks 6 days. Sonographic examinations were categorized as "early" if performed at 31 weeks to 33 weeks 6 days or "late" if performed at 34 weeks to 36 weeks 6 days. We estimated birth weight using the gestation-adjusted projection method, compared errors in prediction of birth weight using the t test and Mann-Whitney U test, and performed a 2-sample test of proportions to compare prediction of macrosomia (birth weight >4000 g).

RESULTS

The early and late groups had similar mean gestational ages at birth (38 weeks 4 days versus 38 weeks 5 days; P = .13) and rates of macrosomia (10.7% versus 12.4%; P = .63). The early group had a greater mean absolute error (336 versus 297 g; P = .03) and percent error (9.9% versus 7.9%; P = .01) in birth weight prediction but a lower mean birth weight (3303 versus 3426 g; P = .02). Sensitivity for prediction of macrosomia was 19% in the early group versus 45% in the late group (P = .07), whereas specificity was similar (98% versus 96%; P = .27).

CONCLUSIONS

Using the gestation-adjusted projection method in our patients with diabetes, we found that sonographic examinations performed at 34 weeks to 36 weeks 6 days better predicted birth weight than those performed at 31 weeks to 33 weeks 6 days.

Early initiation of low-dose aspirin for reduction in preeclampsia risk in high-risk women: a secondary analysis of the MFMU High-Risk Aspirin Study

OBJECTIVE

Early initiation of low-dose aspirin (LDA) may reduce preeclampsia risk. We sought to determine whether LDA was beneficial when initiated <17w0d, within a trial of high-risk women enrolled <26w0d.

STUDY DESIGN

Secondary analysis of the Maternal-Fetal Medicine Units High-Risk Aspirin study, including women enrolled <17w0d, randomized to LDA (60 mg day(-1)) or placebo with chronic hypertension (CHTN, n=186), diabetes (n=191) or prior preeclampsia (n=146). The primary outcome was preeclampsia at any time in pregnancy, secondary outcomes were early preeclampsia (<34w0d), late preeclampsia (⩾34w), small for gestational age (SGA; neonatal birthweight <10th %) and composite (early preeclampsia or SGA). Outcomes were compared by exact Χ(2)-tests.

RESULTS

Baseline characteristics were similar between treatment groups. Aspirin was associated with a lower rate of late-onset preeclampsia ⩾34w (17.36% vs 24.42%, P=0.047), with a 41% reduction in women with CHTN (18.28% vs 31.18%, P=0.041). There were no other significant differences in the outcome.

CONCLUSION

Aspirin initiated <17w0d reduced the risk for late-onset preeclampsia by 29% supporting the practice of early initiation of aspirin in high-risk women.

Degree of public support for household hazardous waste control alternatives

This paper reports information from Massachusetts on attitudes of householders toward alternative approaches and economic solutions to household hazardous waste (HHW) generation and disposal. Residents appear to be aware of the nature of the HHW problem and clearly support action to address the problem. The majority support a law fining householders for the improper disposal of HHW, endorse paying a sales tax on domestic hazardous products to finance safe disposal, and appear willing to drive up to five miles to dispose of HHW twice yearly.

Household hazardous waste in Massachusetts

Household wastes, when disposed of improperly, are hazardous to health. This paper reports a random digit dial telephone survey of Massachusetts households concerning household hazardous waste (HHW) disposal with a 54% response. Of the automotive oil disposed of by 33% of survey households, 57% was deposited in the ground, sewer, or landfill. Annually by household oil disposal in Massachusetts is estimated to be 8.8 million quarts. Four percent of hazardous waste generated in Massachusetts is from households. Improper disposal makes it a major environmental contaminant. More households (41.5%) in smaller communities disposed of oil compared with 26% of households in larger communities. Paint and pesticides were disposed of by 10% of the households, but were dumped on the ground sewer or landfills more than 90% of the time.

The renal effects of sodium chlorite in the drinking water of C57L/J male mice

The increasing concern over the possibility of adverse health effects due to the chlorination of drinking water has led to a search for alternative methods of disinfection. One potential alternative is chlorine dioxide which, when used, gives rise to the end product chlorite. This study investigated the potential of chlorite as a nephrotoxic agent when administered for various lengths of time (30, 90, and 180 days) in a series of concentrations (4, 20, and 100 ppm as sodium chlorite) to C57L/J male via drinking water. Examination by light and transmission electron microscopes did not reveal any evidence of renal pathologies. In addition, no evidence of significant mortality, water consumption differences, body weight change differences, kidney weight change differences, or differences in the percent kidney to body weight ratio was observed between the various levels of treatments.

Ozone induced hematological changes in mouse strains with differential levels of erythrocyte G-6-PD activity and vitamin E status

A single short term in vivo exposure (6 hr) to O3 (i.e., 0.3, 0.9, 1.5 ppm) markedly affected several hematological parameters in males of two mouse strains (C57L/J and A/J) reared on either a vitamin E normal or deficient diet. Of particular significance is that at the lowest concentration employed (i.e., 0.3 ppm), O3 induced marked decreases in red cell ACHE and increases in heinz body formation and osmotic fragility in both mouse strains regardless of diet type. Although the two mouse strains markedly differ in their RBC G-6-PD activity, they did not consistently differ in responses to O3 exposure.

The effect of in vivo ozone exposure to Dorset sheep, an animal model with low levels of erythrocyte glucose-6-phosphate dehydrogenase activity

Female Dorset sheep were exposed in vivo to ambient ozone levels of 0.12 ppm, 0.25 ppm, 0.50 ppm, 0.70 ppm for 2.75 hours and the effects of this exposure upon erythrocytes were studied. Ozone exposure induced biochemical evidence of oxidant stress as indicated by decreases in GSH levels (at 0.5 and 0.7 ppm ozone) and ACHE (at 0.7 ppm), increases in MetHb (from 0.12 ppm upward) and decreases in red blood cell counts (from 0.12 ppm upward). However, only the decrease in GSH levels at the 0.5 ppm ozone exposure was statistically significant (p = 0.05).

The effect of ascorbic acid on copper-induced oxidative changes in the erythrocytes of rats, sheep, and normal humans

Rats, sheep, and normal humans displayed a comparable sensitivity to copper acetate (3 mM)-induced changes in reduced glutathione (GSH) levels in vitro. However, the human erythrocytes were more sensitive than either animal to methemoglobin (METHB) formation with the rat being least sensitive. Ascorbic acid incubation markedly enhanced the occurrence of copper acetate-induced increases in METHB and decreases in GSH in the sheep and humans. However, ascorbic acid incubation reduced the occurrence of copper acetate-induced increases in METHB, while not effecting changes in GSH in rats.

The effect of ascorbic acid on nitrite-induced methemoglobin formation in rats, sheep, and normal human erythrocytes

Interspecies differences were demonstrated with respect to the occurrence of sodium nitrite-induced methemoglobin (METHB) in the erythrocytes of rats, dorset sheep, and normal humans, with the rats displaying approximately 25-33% of the sensitivity of sheep and human erythrocytes. Ascorbic acid incubation along with the nitrite was able to significantly reduce METHB formation in a dose-dependent manner in both rats and humans but not in sheep.

An evaluation of the dorset sheep as a predictive animal model for the response of G-6-PD deficient human erythrocytes to a proposed systemic toxic ozone intermediate, methyl oleate hydroperoxide

Erythrocytes of both G-6-PD deficient humans and Dorset sheep, an animal model with an erythrocyte G-6-PD deficiency, both responded in a dose dependent manner to the oxidant stress of MOHP as measured by decreases in G-6-PD activity, increases in METHB levels and decreases in GSH. However, the human G-6-PD deficient erythrocytes were considerably more sensitive to the formation of METHB than the sheep erythrocytes while the reverse was the case for the GSH parameter. The results suggest a qualitative difference in the response of sheep erythrocytes and human G-6-PD deficient erythrocytes to MOHP that seriously questions the value of the sheep erythrocyte as a quantitatively accurate predictive model.

The effect of ascorbic acid on sodium nitrite-induced methemoglobin formation in glucose-6-phosphate dehydrogenase-deficient erythrocytes

Ascorbic acid significantly reduced the occurrence of sodium nitrite-induced methemoglobin (METHB) formation in a dose-dependent manner in erythrocytes from glucose-6-phosphate dehydrogenase (G-6-PD)-deficient humans in vitro. The ascorbic acid treatment, however, also decreased levels of reduced GSH in a dose-dependent manner, a response indicative of oxidant stress to the erythrocyte membrane. The latter findings are inconsistent with the hypothesis that ascorbic acid supplementation in G-6-PD-deficient humans may help compensate for inherently low levels of erythrocyte GSH. Finally, the ascorbic acid-induced reduction of METHB values, while of statistical significance, does not appear to be of clinical significance.

An evaluation of the dorset sheep as a predictive animal model for the response of glucose-6-phosphate dehydrogenase-deficient human erythrocytes to a proposed systemic toxic ozone intermediate, methyl oleate ozonide

Erythrocytes of both glucose-6-phosphate dehydrogenase (G-6-PD)-deficient humans and Dorset sheep, an animal model with an erythrocyte G-6-PD deficiency, responded in a dose-dependent manner to the oxidant stress of methyl oleate ozonide (MOO) as measured by decreases in G-6-PD activity, increases in methemoglobin (METHB) levels, and decreases in GSH. However, the human G-6-PD-deficient erythrocytes were considerably more sensitive to the formation of METHB than the sheep erythrocytes while the reverse was the case for the GSH parameter. The results suggest a qualitative difference in the response of sheep erythrocytes and human G-6-PD-deficient erythrocytes to MOO that seriously questions the value of the sheep erythrocyte as a quantitatively accurate predictive model.

The effect of methyl oleate hydroperoxide, a possible toxic ozone intermediate, on human normal and glucose-6-phosphate dehydrogenase-deficient erythrocytes

Erythrocytes of both normal and glucose-6-phosphate dehydrogenase (G-6-PD)-deficient humans responded in a dose-dependent manner to the oxidant stress of methyl oleate hydroperoxide (MOHP) as measured by decreases in G-6-PD activity, increases in methemoglobin (METHB) levels, and decreases in reduced glutathione (GSH). The G-6-PD-deficient erythrocytes displayed a markedly enhanced sensitivity to MOHP-induced decreases in G-6-PD activity and METHB increases while being less sensitive than normal erythrocytes to changes in GSH levels.

Health effects among newborns after prenatal exposure to ClO2-disinfected drinking water

Because chlorination of potable surface waters may be associated with increased risk of carcinogenicity, substitute methods for the routine disinfection of public water supplies are being explored. As part of this search, it is especially important that the potential health effects of each alternative method should be considered. Chemical treatment of drinking water by chlorine dioxide (ClO2) is a likely alternative mode of disinfection. Two common by-products of the ClO2 disinfection of surface water are chlorate and chlorite. These oxidants may have negative health effects on certain high risk groups. Newborns, in particular, would seem to be at increased risk to red cell damage from oxidant stress. The historical record study being reported here compares the morbidity and mortality experience of newborns in two similar communities, one of which used chlorination and the other which used high levels of chlorine dioxide for potable water disinfection. A statistically significant positive association was found between exposure of the mother to ClO2-treated water during pregnancy and prematurity of the newborn as assessed by the attending physician and by a greater weight loss after birth. The rates of jaundice, birth defects and fetal and neonatal mortality did not differ significantly between communities. Because of the limitations of the study design, the findings reported here should be considered suggestive rather than definitive.

Toxicological effects of chlorite in the mouse

When exposed to a maximum level of 100 ppm chlorine dioxide in their drinking water, neither A/J or C57L/J mice exhibited any hematologic changes. Chlorite exposure under similar conditions produced increases for red blood cells in osmotic fragility, mean corpuscular volume, and glucose-6-phosphate dehydrogenase activity for both strains. Chlorite exposure of pregnant A/J mice resulted in a significant decrease in the weight of pups at weaning and a lower average birth to weaning growth rate. Mice exposed to as much as 100 ppm sodium chlorite (NaClO2) in their drinking water for up to 120 days failed to demonstrate any histopathological changes in kidney structure.

Does cadmium exposure reduce the metabolism of ethanol?

It is proposed that persons exposed to elevated levels of cadmium via occupation, diet, or cigarette smoking will exhibit a diminished capability to metabolize ethanol via the action of the zinc dependent enzyme, alcohol dehydrogenase (ADH). This follows from the observation that cadmium can replace the zinc in liver ADH and inactivate it.

G6PD-deficiency: a potential high-risk group to copper and chlorite ingestion

Although humans may accept fairly large amounts of orally ingested copper (0.25 to 1.0 gm) without visible harmful effects, patients with Wilson's disease, and persons with G6PD deficiency may represent persons at unusual risk to hemolytic anemia from ingestion of Cu(II). This study reports that in vitro exposure of G6PD deficient red blood cells to copper produced marked elevations of methemoglobin and decreases in GSH when compared with normal red cells. Chlorite, a by-product of chlorine dioxide disinfection of water, produced decreases in GSH and G6PD activity, while increasing methemoglobin levels markedly over red cells with normal G6PD activity. The combined action of chlorite and copper was additive in producing increased levels of hemoglobin and decreases in levels of GSH and G6PD deficient cells. The combined ingestion of copper and chlorite may represent an increased risk to persons with G6PD deficiency.

Groups at potentially high risk from chlorine dioxide treated water

Chlorite, a by-product of chlorine dioxide disinfection of water, is a strong oxidant compound that produces markedly exaggerated effects in vitro on red cells of G6PD deficient humans when compared to normal human cells. Levels of methemoglobin are significantly greater and GSH levels significantly lower in the G6PD deficient cells than in normal cells after chlorite exposure. Persons with G6PD deficiency may be 3 to 4 times more likely to develop hemolytic anemia from chlorite exposure as persons with normal activity levels when GSH levels are used as a measure of susceptibility. The proposed use of chlorine dioxide as an alternate disinfectant for drinking water supplies should consider this potential high risk group.

The effects of chlorine dioxide and sodium chlorite on erythrocytes of A/J and C57L/J mice

Because chlorinated surface drinking water supplies have been implicated in an increased risk of cancer, alternative methods of disinfection are being proposed; chlorine dioxide is the most seriously considered. This study reports that chlorine dioxide exposure of two strains of laboratory mice (A/J and C57L/J) to 100 ppm chlorine dioxide in their drinking water for 30 days produced no changes in 11 hematological parameters measured. Chlorite (a product formed from chlorine dioxide disinfection) produced increases in MCV (mean corpuscular volume); osmotic fragility; G6PD (glucose-6-phosphate dehydrogenase) activity; and the number of acanthocytes at exposure to 100 ppm, but not 1.0 or 10.0 ppm. These findings are consistent with membrane damage to the red cell and, in particular, the lipid fraction. Since chlorite is formed at a rate of 50 percent of the chlorine dioxide demand, serious consideration must be given to limiting chlorite formation before chlorine dioxide is adopted as a disinfectant to replace chlorine.

Does the rodent model adequately predict the effects of ozone induced changes to human erythrocytes?

There is an important need to develop animal models to simulate the response of humans to environmental pollutants. The rodent model has been commonly employed to predict the effects of ambient ozone on human RBCs. The use of rodent models for such a purpose is questioned. This challenge is based on the a) ability of mice to significantly enhance ascorbic acid synthesis following ozone stress, b) the ability of ascorbic acid to prevent oxidant [i.e. acetylphenylhydrazine (APH)] stress to human G-6-PD deficient RBCs and c) the lack of ability of humans to synthesize ascorbic acid.

A survey of fungal flora in respiratory therapy equipment

This survey, designed to detect the presence of fungi in respiratory therapy equipment by using a modification of the method of Nazemi et al, indicated significant numbers of fungi in 6 of 30 respiratory therapy devices used in the home, while none of 138 devices used in the hospital showed significant numbers of fungi. Species of fungi detected in large numbers were all yeasts and yeast-like organisms. Additionally, 50% of home devices were found to be moderately to heavily contaminated with either bacteria or fungi, or both, while only 3.6% of the hospital equipment achieved similar levels of contamination (P less than or equal to 0.005), and in these cases, bacteria were the primary contaminants. It was concluded that fungi merited consideration as potential contaminants of respiratory therapy equipment, and that home care respirators presented significantly greater changes for possibly hazardous contamination than did hospital-maintained equipment.

The possible role of hypertension in aggravating hemolytic episodes in G-6PD deficient persons

Approximately 13 percent of American Negro males carry a mutant [A-variant] glucose-6-phosphate dehydrogenase enzyme in their red blood cells that predisposes them to hemolytic episodes following exposure to oxidant drugs such as primaquine. Most hemolytic episodes to standard prophylactic treatment are mild and self-limited, but as many as 2 percent of Negro males develop severe hemolysis when similarly treated. The exaggerated response may be due in part to the combination of G-6-PD deficiency and hypertension since hypertension can cause red cell fragmentation, and the stressed cells of G-6-PD deficient person would be more sensitive to such fragmentation.

Can elevated levels of copper in drinking water precipitate aucte hemolysis in G-6-PD deficient individuals?

The hypothesis that elevated levels of copper in drinking water may be a factor in the precipitation of acute hemolysis in those with a G-6-PD deficiency in their erythrocytes is developed. The present U.S. EPA drinking water standards do not have a primary (or human health) standard for copper but only a secondary standard which is designed to prevent an unacceptable taste. Because of the widespread occurrence of elevated levels of copper in drinking water in areas where the water is corrosive and the households have copper piping, it is recommended that environmental health regulatory agencies develop a risk assessment concerning the effects of copper on those high risk groups who are predisposed to develop a copper induced hemolysis.

Potential health effects of chlorine dioxide as a disinfectant in potable water supplies

Chlorination of potable water supplies high in organics may yield carcinogenic compounds such as trihalomethanes. Chlorine dioxide has been proposed as an alternative disinfectant to chlorine. However, chlorine dioxide is a strong oxidant that forms significant amounts of chlorite when added to potable water supplies, and chlorite is similar to nitrite in its molecular structure and may be similar in its mechanism of methemoglobin production. Nitrites and chlorites are thought to act synergistically to produce MetHb. Neonates and persons with G-*-PD deficiency are likely to be unusually susceptible to MetHb formation from these compounds because their red cells lack the metabolic machinery to adequately protect against oxidant stress. Since male blacks represent the largest population in the U.S. to be G-6PD deficient, Black male neonates may represent the group at highest risk to the use of chlorine dioxide as a disinfectant in the nations water supplies.

The effect of microbial mycolytic agents on Trichophyton rubrum

Chitinolytic microorganisms isolated from forest soil and from healthy gypsy moth larvae (Porthetria dispar (L.) were screened for their ability to lyse Trichophyton rubrum mycelia. A few of these isolates were mycolytic on both autoclaved and on actively growing, intact, T. rubrum mycelia. Supernatants from these isolates, utilizing live T. rubrum as the sole carbon source, showed the same mycolytic ability. Assays of the supernatants for enzymatic activity revealed exocellular, stable enzymes that releases reducing substances including N-acetylglucosamine from the mycelia.