Molecular characterization of a heme-binding protein of Bacteroides fragilis BE1

An iron-repressible 44-kDa outer membrane protein plays a crucial role in the acquisition of heme by the anaerobic bacterium Bacteroides fragilis. The DNA sequence of the gene encoding the 44-kDa protein (hupA) was determined. The hupA gene encodes a protein of 431 amino acid residues with a calculated molecular mass of 48,189 Da. The hupA gene is preceded by an open reading frame of 480 bp that probably encodes a protein with a calculated molecular mass of 18,073 Da. hupA and this open reading frame are likely organized in an operon, and a sequence homologous to the Escherichia coli consensus Fur box was present in the putative promoter region of the operon. Heme-binding studies showed that HupA binds heme. Analysis of the deduced amino acid sequence revealed signature heme-binding consensus motifs, characteristic of heme lyases. Subcellular localization studies in E. coli revealed that HupA was mainly found in the cytoplasmic membrane but not in the outer membrane of E. coli. This suggested that B. fragilis uses another strategy for the translocation of this outer membrane protein across its cell envelope than E. coli does. HupA did not have significant homology with other putative bacterial heme receptors.     

Pancreatic cancer: treatment with neutron irradiation alone and with chemotherapy

PURPOSE: To evaluate neutron irradiation alone and with chemotherapy to treat inoperable pancreatic cancer. MATERIALS AND METHODS: Between 1977 and 1994, 173 patients (60 men, 113 women, aged 43-77 years [mean, 59 years]) with unresectable adenocarcinoma of the exocrine pancreas were treated, 106 with neutron irradiation alone and 67 with concomitant chemotherapy (fluorouracil [5-FU]). At follow-up, which was performed at 2-month intervals until death (range, 4-64 months), clinical status was recorded, noting the presence of overt metastasis and the onset of any major complications. Actuarial (Kaplan-Meier) survival tables were computed for both groups. RESULTS: For neutron irradiation alone and neutron irradiation plus chemotherapy, median survival times were 6 months and 9 months, respectively; actuarial survival rates at 3 years were 0 and 7%, respectively; major reactions (grade 3 or higher [scale of the Radiation Therapy Oncology Group and European Organization for Research and Treatment of Cancer]) occurred in 19 (18%) and 17 (25%) patients, respectively; and severe complications (grade 4) occurred in five (5%) and four (6%) patients, respectively. Most deaths were due to metastatic disease rather than to failure of local control. CONCLUSIONS: Neutron irradiation obliterated pancreatic adenocarcinoma at the primary site but has no effect on long-term survival. With more effective concomitant chemotherapy to prevent metastasis, local control of pancreatic cancer with neutron irradiation could lead to increased long-term survival.     

Small cell carcinoma of gallbladder: report of two cases

Extrapulmonary small cell carcinoma has been reported from multiple sites, including the gallbladder. Small cell carcinoma of the gallbladder is a very rare tumor, found usually in elderly women and associated with cholelithiasis. It carries a grave prognosis, metastasizing early and causing death shortly after diagnosis. Treatment of metastatic disease with two different chemotherapeutic regimens has been shown to improve survival. To the best of our knowledge, this tumor has not been previously reported in a black individual, or in any subject less than 49 yr or more than 79 yr old. We report two cases: one is the first black and youngest reported case. The second is the oldest person reported with this rare malignancy. Radiological studies such as ultrasound and CT scan were useful in evaluating tumor spread and follow-up.     

Methodology of serial ECG classification using an adaptation of the NOVACODE for Q wave myocardial infarction in the Bypass Angioplasty Revascularization Investigation (BARI)

Serial electrocardiographic (ECG) changes are a critical component of the diagnostic algorithm for classification of myocardial ischemic events in large-scale clinical trials. This study describes a computerized serial ECG classification program developed at the St. Louis University Core ECG Laboratory for use in the Bypass Angioplasty Revascularization Investigation (BARI) trial, in which patients with multivessel coronary artery disease were randomized to receive either coronary artery bypass grafting or percutaneous transluminal coronary angioplasty. The St. Louis University program detects and codes serial changes in Q, ST, and T wave items according to Minnesota code (MC) criteria using a modified NOVACODE hierarchical classification system. Measurements using a seven-power calibrated coding loupe are used to generate the MC from a customized software program. Significant minor or major changes are detected by the serial comparison program and referred to a physician coder for verification. Serial comparison coding rules are used to adjust for weaknesses in the standard MC classification system resulting from instability at decision boundaries. Of 4,244 BARI randomized and registry study participants with follow-up ECGs received at the Core ECG Laboratory as of March 1995, a grade 2 MC Q wave progression was noted in 568 participants (13.4%) using MC criteria alone, as compared with 367 (8.6%) after the St. Louis University coding rules were applied. The incidence of grade 1 MC Q wave progressions was 16.4% (697/4,244) versus 6.1% (259/4,244) when the St. Louis University program was applied. Intraobserver variability for grade 2 Q wave progression codes determined from a sample of 812 serial.     

A comparison of in vivo and in vitro methods for determining availability of iron from meals

A comparison is made between in vitro and human and rat in vivo methods for estimating food iron availability. Complex meals formulated to replicate meals used by Cook and Monsen (Am J Clin Nutr 1976;29:859) in human iron availability trials were used in the comparison. The meals were prepared by substituting pork, fish, cheese, egg, liver, or chicken for beef in two basic test meals and were evaluated for iron availability using in vitro and rat in vivo methods. When the criterion for comparison was the ability to show statistically significant differences between iron availability in the various meals, there was substantial agreement between the in vitro and human in vivo methods. There was less agreement between the human in vivo and the rat in vivo and between the in vivo and the rat in vivo and between the in vitro and the rat in vivo methods. Correlation analysis indicated significant agreement between in vitro and human in vivo methods. Correlation between the rat in vivo and human in vivo methods were also significant but correlations between the in vitro and rat in vivo methods were less significant and, in some cases, not significant. The comparison supports the contention that the in vitro method allows a rapid, inexpensive, and accurate estimation of nonheme iron availability in complex meals.     

Plasma lipids, lipoproteins, and triglyceride turnover in eu- and hypo-thyroid rats and rats on a hypocaloric diet

Lipid and lipoprotein concentration, and triglyceride turnover were studied in control, thyroidectomized, and pair-fed control rats (pair-fed to match the food intake of the thyroidectomized rats). Thyroidectomy induced a significant increase in plasma cholesterol (and low density lipoprotein) concentrations and a decrease in plasma triglyceride (and very low density lipoprotein) concentrations. Changes in similar direction but of smaller magnitude were observed in the plasma of the pair-fed control rats. To further investigate triglyceride metabolism in these three groups of animals, triglyceride turnover was studied in fasted, unrestrained, and unanesthetized rats, following injection of [2-3H]glycerol. Peak incorporation of [2-3H]glycerol into plasma triglyceride occurred in all three groups of animals at 25 min after precursor administration, although the maximal incorporation was substantially lower in the thyroidectomized group than in either of the control groups. Thereafter, plasma triglyceride radioactivity decayed monoexponentially with a half-life of 24 +/- 1 min for both normal and pair-fed control rats, compared with the half-life of 41 +/- 3 min observed in the thyroidectomized rats. The calculated apparent fractional catabolic rates were thus 0.029 min-1 for both control groups and only 0.017 min-1 for the thyroidectomized animals. The apparent total catabolic rates of plasma triglyceride were 299 +/- 11, 138 +/- 11, and 48 +/- 4 micrograms triglyceride . min-1 for the normal controls, pair-fed controls, and thyroidectomized rats, respectively. These data further emphasize the importance of thyroid hormones in regulating plasma lipid and lipoprotein metabolism and, specifically, indicate that hypothyroidism results in a reduction of triglyceride secretion into, and the removal from, circulation. Furthermore, evidence was presented that the decreased caloric intake of the hypothyroid animals cannot, in itself, account for this observation.