Molecular modelling of human CYP2E1 by homology with the CYP102 haemoprotein domain: investigation of the interactions of substrates and inhibitors within the putative active site of the human CYP2E1 isoform

1. The construction of a three-dimensional model of human CYP2E1 is reported. It is based on homology with the haemoprotein domain of the unusual bacterial P450, CYP102, which is of known crystal structure. 2. Interactive docking of a number of human CYP2E1 substrates is consistent with their known positions of CYP2E1-mediated metabolism, where specific interactions with key active site amino acid side-chains appear to rationalize the binding and orientation of substrate molecules. 3. Amino acid residues within the putative active site of human CYP2E1, including those associated with the binding of substrates and inhibitors, are shown to correspond with those identified by site-directed mutagenesis experiments conducted on CYP2 family isoforms, and they are known to affect substrate metabolism regioselectivity. 4. Consequently, it was found that the CYP2E1 active site exhibits complementarity with the structural characteristics of known substrates and inhibitors of this enzyme, including their relatively low molecular weights and disposition of hydrogen bond-forming groups.     

Leptospirosis presenting with erythema nodosum

An illness due to a leptospiral infection in a boy aged 12 years is described which, in addition to presenting with severe fever, malaise, and aseptic meningitis, showed the rare features of severe bradycardia and erythema nodosum.     

Duodenal bacterial flora in early stages of transient monosaccharide intolerance in infants

The aerobic and anaerobic bacterial flora of the duodenum were studied in 10 infants with transient monosaccharide intolerance. 5 infants had protracted diarrhoea after an episode of acute gastroenteritis and 5 had acute gastroenteritis. The duration of monosaccharide intolerance ranged from 1 to 20 days. Serial intubations were performed on 8 infants. In 5 of 8 cases the bacterial flora were of a normal type at the first intubation at 0--4 days after the onset of monosaccharide intolerance. In 4 of those 5 patients there was an increase in bacterial count a few days later and anaerobes appeared. These findings are not consistent with the suggestion that monosaccharide intolerance is caused by abnormal bacteria in the upper small bowel.     

Long-term results of surgical treatment for pulmonary valve stenosis

109 children who survived surgical treatment for isolated pulmonary valve stenosis were followed for up to 17 years. In all the postoperative status was assessed as satisfactory. Cardiac catheterization repeated in 43 gave a resting valve gradient below 40 mmHg. The 22 children whose pulmonary valves had been excised were as healthy as the 87 who had undergone pulmonary valvotomy. Consideration was given to the desirable length of postoperative review. Except for the few children with symptoms before operation, a postoperative increase in exercise tolerance was not a feature.     

Studies of malformation syndromes of man XIB: the cerebro-hepato-renal syndrome of zellweger: Comparative pathology

A study of 11 autopsied cases of the cerebro-hepato-renal syndrome of Zellweger (ZS) is reported. All cases had severe, peristent congenital hypotonia, hepatic lobular disarray, renal cortical cysts and pulmonary hypoplasia. Many had cardiovascular malformations, hepatomegaly, cerebral cortical gyral maldevelopment and pancreatic islet hyperplasia. Additional, less frequent findings are delineated. Results of iron content studies of hepatic and renal tissues are related to age of survival and possible development of fibrosis.Supported in part by American Cancer Society Junior Faculty Clinical Fellowship 237A and USPH/NIH Grants GM 20130, GM 15422 and 5 K04 HD 18982. Submitted in part as Paper No. 1881 from the University of Wisconsin Genetics Laboratory.     

Diffusion-Weighted MRI Correlates of Subacute Methotrexate-Related Neurotoxicity

SummaryPurpose: Chemotherapy with alkylating agents is of proven efficacy in recurrent anaplastic oligodendroglioma (AO) with reported response rates ranging between 50% and 70%. The response of newly diagnosed AO to initial treatment with temozolomide (TMZ) has not yet been reported. This study evaluated the response and time to tumor progression of newly diagnosed AO initially treated with TMZ.Patients and methods: Twenty patients with a median age of 47 (range: 26–65) received a median of 14 (range: 3–24) cycles of TMZ as their first modality of therapy following diagnosis of AO. Treatment was given every 28 days for 5 days at a starting dose of 200 mg/m²/d and was continued for 24 cycles unless toxicity or tumor progression required withdrawal of TMZ. MRI evaluations were repeated every 8 weeks and scales of Karnofsky performance status (KPS) and of neurological function were used to assess clinical response.Results: Clinical improvement was observed in 60% of the patients with statistically significant gain measured by KPS and the neurologic function scales. The objective response rate was 75%, and median time to tumor progression was 24 months. Maximal objective response was reached within a median of 6 months (range: 3–12). Tumors with 1p loss had longer progression free survival compared to tumors without deletions (PFS at 24 months: 1p LOH = 100%, 1p intact = 20%; P = 0.057). TMZ was well tolerated with only two events of grade 3/4 hematological toxicity.Conclusions: Newly diagnosed AO demonstrates a high rate of response to initial therapy with TMZ, similar to the response reported for PCV combination therapy. Further studies are needed to determine the optimal duration of treatment and whether radiotherapy should immediately follow chemotherapy.     

Effect of adjuvant breast cancer chemotherapy on cognitive function from the older patient’s perspective

SummaryPurpose This longitudinal prospective study describes the older breast cancer patient’s perception of the cognitive impact of adjuvant chemotherapy.Methods A total of 50 patients ≥age 65 with stage I to III breast cancer enrolled in this IRB-approved prospective study. Of the 50, 3 refused postchemotherapy testing and 2 had a cerebrovascular accident (CVA) during therapy, leaving 45 evaluable patients. The Squire Memory Self-Rating Questionnaire, given before and 6 months after chemotherapy, measured patients’ perceptions of the ability to learn new information, of working memory, and of remote learning capabilities.Results Mean age was 70 years (range 65–84). Breast cancer stages were: I (33%), II (64%), III (2%). A 51% (23/45) of study participants perceived a decline in memory from before to 6 months after completion of chemotherapy. Patients who perceived a poorer memory than average before chemotherapy were more likely to report further memory deterioration after chemotherapy (19/30, 63%) than patients who perceived that their memory was average or better than average prior to chemotherapy (4/15, 27%). The memory domain most likely to be perceived as affected was the ability to learn new information (22/45, 49%) compared to remote memory (9/45, 20%) or working memory (13/45, 29%) capabilities.Conclusion Approximately half of these older women perceived a decline in cognitive function from before to 6 months after chemotherapy. This perceived decline in cognitive function was most pronounced in patients with preexisting memory complaints. Further prospective study is needed to confirm these observations, correlate perceived memory changes with objective findings, and identify subgroups at special risk.     

Effect of microhydrin on blood lactate, protein carbonyls, and glutathione status in rats before and after aerobic exercise

To examine the effects of an antioxidant treatment on blood lactate, protein carbonyls (PC), and glutathione status, 42 male rats were assigned to either a control treatment (water, C) or one of two Microhydrin treatments (added to water, MH I or MH II). Rats from each treatment were assigned to either exercise (60 min of running) or rest. A treatment-by-time interaction was noted for blood lactate, with elevations only in the C and MH I treatments post-exercise (approximately 2.54 and 2.5 mM, respectively). Both treatment and time main effects were noted for PC. Exercise resulted in an increase in PC for both Microhydrin treatments with significantly greater PC compared to C. Total blood glutathione was unaffected by treatment or exercise. Exercise increased the ratio of oxidized to total glutathione and the MH II treatment resulted in a greater ratio compared to the other treatments. In conclusion, MH II results in lower blood lactate, while resulting in an increase in the concentration of oxidized protein and glutathione, suggesting heightened oxidative stress.