The incidence of colorectal cancer (CRC) is dramatically higher in African Americans (AAs) than in Native Africans (NAs) (60:100,000 vs. <1:100,000) and slightly higher than in Caucasian Americans (CAs). To explore whether the difference could be explained by interactions between diet and colonic bacterial flora, we compared randomly selected samples of healthy 50- to 65-y-old AAs (n = 17) with NAs (n = 18) and CAs (n = 17). Diet was measured by 3-d recall, and colonic metabolism by breath hydrogen and methane responses to oral lactulose. Fecal samples were cultured for 7-alpha dehydroxylating bacteria and Lactobacillus plantarum. Colonoscopic mucosal biopsies were taken to measure proliferation rates. In comparison with NAs, AAs consumed more (P < 0.01) protein (94 +/- 9.3 vs. 58 +/- 4.1 g/d) and fat (114 +/- 11.2 vs. 38 +/- 3.0 g/d), meat, saturated fat, and cholesterol. However, they also consumed more (P < 0.05) calcium, vitamin A, and vitamin C, and fiber intake was the same. Breath hydrogen was higher (P < 0.0001) and methane lower in AAs, and fecal colony counts of 7-alpha dehydroxylating bacteria were higher and of Lactobacilli were lower. Colonic crypt cell proliferation rates were dramatically higher in AAs (21.8 +/- 1.1% vs. 3.2 +/- 0.8% labeling, P < 0.0001). In conclusion, the higher CRC risk and mucosal proliferation rates in AAs than in NAs were associated with higher dietary intakes of animal products and higher colonic populations of potentially toxic hydrogen and secondary bile-salt-producing bacteria. This supports our hypothesis that CRC risk is determined by interactions between the external (dietary) and internal (bacterial) environments.

The HIV/AIDS epidemic likely played a significant role in the 1979-1985 deviation, but not subsequently. Furthermore, EPTB as a proportion of total TB cases has remained high. Further studies to delineate the etiologies of these findings are needed.

INTRODUCTION:Pneumatosis intestinalis (PI) is the presence of gas within the wall of the small or large intestine. While the pathogenesis is poorly understood, the etiology is often secondary to ischemia, obstruction, or on occasion, an endoscopic procedure.CASE PRESENTATION: 50-year-old male with past medical history of chronic kidney disease stage 4 and uncontrolled insulindependent type 2 diabetes presented with decreased urine output, shortness of breath and abdominal distention of 3 days. On initial exam, the abdomen was firm as well as diffusely tender to palpation. He was alert and oriented with no focal deficits noted. Initial CT abdomen revealed a considerable volume of stool within the colon. Hepatic and abdominal vasculature were unremarkable. One lactulose enema was given without initial complication at 1155 AM. At 1345 the patient was documented to be slightly lethargic and weak by physical therapy. At 1435 the patient was found to be unresponsive to verbal or tactile stimuli and developed emesis. Physical exam revealed tachypnea, sluggish pupillary response bilaterally, and rigid abdomen. Stat CT head revealed gas within multiple left cerebral veins. Repeat CT abdomen showed interval colonic pneumatosis intestinalis and intrahepatic portal venous gas suspected by radiology to be related to recent enema. Emergent intubation was performed for stabilization. Transfer to a center capable of providing hyperbaric oxygen therapy to a ventilated patient was initiated. Unfortunately, due to lack of resources and considerable distance to a capable facility, ground transport was not an option. To further complicate the picture, air transport was delayed by several hours due to severe weather. Following the patient's arrival at the outside facility, the family elected for comfort measures and the patient subsequently expired shortly thereafter.DISCUSSION: One proposed mechanism of PI is termed the mechanical theory. Gas dissects into the wall of the intestines at a point of disrupted mucosal integrity. This has been reproduced by insufflating an excised colonic segment in one study [1]. Enema has been shown to cause massive portal venous gas [2] while retrograde venous air embolism has been demonstrated [3], most often following central line removal. In this case, air emboli traveled through portal venous circulation, then retrograde after the level of the heart to the cerebral vessels. To our knowledge this is the only documented case in which enema has resulted in stroke.CONCLUSIONS: Pneumatosis intestinalis is an exceedingly rare complication of enema. Being aware of this possibility can provide early recognition and intervention, leading to better outcomes for future patients.

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