Processed meat intake, CYP2A6 activity and risk of colorectal adenoma

Red and processed meat intake is associated with increased risks of both colorectal adenoma and cancer. Processed meats contain nitrate and nitrite, precursors of N-nitroso compounds (NOCs); furthermore, meats cooked at high temperatures contain heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs). Specific NOC, HCA and PAH are mutagens and animal carcinogens. We conducted a case-control study of 146 cases of colorectal adenoma, diagnosed at sigmoidoscopy or colonoscopy, and 228 polyp-free controls. We calculated odds ratios (ORs) [and 95% confidence intervals (CIs)] and found a 2-fold increased risk in the highest, compared with the lowest, quartile of processed meat intake (95% CI = 1.0-4.0). We estimated nitrate and nitrite intake from meat using published data from the literature as well as from actual measurements of meats analyzed recently. We evaluated the interaction of processed meat and nitrate plus nitrite intake with CYP2A6 activity, an enzyme able to metabolize some NOC to their carcinogenic form. Results for both methods of estimating nitrate and nitrite intake were similar; compared with the lowest, the highest quartile based on measured values was associated with a 2-fold elevated risk (95% CI = 1.0-3.9). Adjustment for the HCA 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) attenuated the association (OR = 1.6, 95% CI = 0.8-3.2), but other HCA and PAH had minimal effect. Higher CYP2A6 activity was not associated with risk and there was no evidence of an interaction of CYP2A6 activity with nitrate and nitrite intake. Our results suggest that nitrite and nitrate intake from processed meat intake increases the risk of colorectal adenoma after accounting for HCA and PAH.

An epidemic of corneal destruction caused by plasma gas sterilization. The Toxic Cell Destruction Syndrome Investigative Team

BACKGROUND

Toxic endothelial cell destruction (TECD) syndrome after intraocular ophthalmic surgery is rare and can result from exposure to a variety of toxins. During January 8 to 14, 1998, 6 patients developed TECD with corneal edema associated with unreactive or dilated pupils at Hospital A.

METHODS

A case patient was any Hospital A patient with TECD within 24 hours after surgery during January 5 to 14, 1998 (epidemic period). A control was any hospital A ophthalmic surgery patient without TECD during the epidemic period. The medical records of hospital A ophthalmology surgery patients during the pre-epidemic (ie, September 1, 1997-January 4, 1998) and epidemic periods were reviewed. Inductively coupled plasma atomic emission spectrometry was used to detect trace inorganic elements on sterilized surgical instruments. Cannulated surgical instruments and laboratory rinsates were perfused directly to the corneal endothelium of isolated rabbit and human corneas. Corneal endothelial ultrastructure and swelling were assessed.

RESULTS

The rate of TECD at hospital A was higher during the epidemic than pre-epidemic period (6/12 vs 0/118, P<.001). The only change during the periods was the introduction, on November 5, 1997, of a new sterilization method, AbTox Plazlyte, for sterilization of ophthalmic surgery instruments. Findings from spectrometry revealed that copper and zinc residues were higher in instruments sterilized with Plazlyte than in those sterilized with ethylene oxide (median copper value, 7.64 mg/L vs 0.14 mg/L, respectively, P =.02; median zinc value, 5.90 mg/L vs 1.35 mg/L, respectively, P =.2). Corneal endothelial perfusion of Plazlyte sterilized-instrument rinsates or laboratory solution with copper and zinc produced irreversible damage, similar to toxic corneal endothelial destruction, to rabbit and human corneas.

CONCLUSION

A new sterilization method degraded brass to copper and zinc on cannulated surgical instruments resulting in TECD of the cornea. Arch Ophthalmol. 2000;118:1167-1176

Multistate outbreak of hemolysis in hemodialysis patients traced to faulty blood tubing sets

BACKGROUND

Hemolysis associated with hemodialysis is rare. The most frequent causes of hemodialysis-associated hemolysis are chemical contamination, heat, or mechanical injury of erythrocytes from occluded or kinked hemodialysis blood lines. When patients in three states developed hemolysis while undergoing hemodialysis between May 13 and 23, 1998, an investigation was initiated.

METHODS

A case-patient was defined as any patient at healthcare facilities A (Nebraska), B (Maryland), or C (Massachusetts) during May 13 through 23, 1998 (epidemic period), who had hemolysis diagnosed > or =48 hours after undergoing hemodialysis. To identify case-patients and to determine background rates, the medical records of patients from facilities A, B, and C who were undergoing hemodialysis during the epidemic and pre-epidemic (that is, May 5 through 19, 1998) periods were reviewed. Experiments simulating hemodialysis with the same lot numbers of hemodialysis blood tubing cartridge sets used on case- and control-patients were conducted.

RESULTS

The rates of hemolysis among patients at facilities A, B, and C were significantly higher during the epidemic than the pre-epidemic period (13 out of 118 vs. 0 out of 118, P < 0.001; 12 out of 298 vs. 0 out of 298, P = 0.001; and 5 out of 62 vs. 0/65, P = 0.03, respectively). All case-patients had hemolysis. Twenty (66%) had hypertension. Eighteen (60%) had abdominal pain, and 10 (36%) were admitted to an intensive care unit. There were two deaths. The only commonality among the three outbreaks was the use of the same lot of disposable hemodialysis blood tubing from one manufacturer. Examination of the implicated hemodialysis blood tubing cartridge sets revealed narrowing of an aperture through which blood was pumped before entering the dialyzers. In vitro experiments with the hemodialysis blood tubing revealed that hemolysis was caused by increased pressure on erythrocytes as they passed through the partially occluded hemodialysis blood tubing.

CONCLUSIONS

Our investigation traced the multiple hemolysis outbreaks to partially occluded hemodialysis blood tubing produced by a single manufacturer. On May 25, 1998, the manufacturer issued a voluntary nationwide recall of the implicated lots of hemodialysis blood tubing cartridge sets.

The association of religiosity with overweight/obese body mass index among Asian Indian immigrants in California

OBJECTIVE

The aim of this study was to examine the association between religiosity and overweight or obese body mass index among a multi-religious group of Asian Indian immigrants residing in California.

METHODS

We examined cross-sectional survey data obtained from in-language telephone interviews with 3228 mostly immigrant Asian Indians in the 2004 California Asian Indian Tobacco Survey using multivariate logistic regression.

RESULTS

High self-identified religiosity was significantly associated with higher BMI after adjusting for socio-demographic and acculturation measures. Highly religious Asian Indians had 1.53 greater odds (95% CI: 1.18, 2.00) of being overweight or obese than low religiosity immigrants, though this varied by religious affiliation. Religiosity was associated with greater odds of being overweight/obese for Hindus (OR 1.54; 95% CI: 1.08, 2.22) and Sikhs (OR 1.88; 95% CI: 1.07, 3.30), but not for Muslims (OR 0.69; 95% CI: 0.28, 1.70).

CONCLUSIONS

Religiosity in Hindus and Sikhs, but not immigrant Muslims, appears to be independently associated with greater body mass index among Asian Indians. If this finding is confirmed, future research should identify potentially mutable mechanisms by which religion-specific religiosity affects overweight/obesity risk.