The vascular effects of different arginase inhibitors in rat isolated aorta and mesenteric arteries.

BACKGROUND AND PURPOSE: Arginase and nitric oxide (NO) synthase share the common substrate L-arginine, and arginase inhibition is proposed to increase NO production by increasing intracellular levels of L-arginine. Many different inhibitors are used, and here we have examined the effects of these inhibitors on vascular tissue. EXPERIMENTAL APPROACH: Each arginase inhibitor was assessed by its effects on isolated rings of aorta and mesenteric arteries from rats by: (i) their ability to preserve the tolerance to repeated applications of the endothelium-dependent agonist acetylcholine (ACh); and (ii) their direct vasorelaxant effect. KEY RESULTS: In both vessel types, tolerance (defined as a reduced response upon second application) to ACh was reversed with addition of L-arginine, (S)-(2-boronethyl)-L-cysteine HCl (BEC) or N(G)-Hydroxy-L-arginine (L-NOHA). On the other hand, N(omega)-hydroxy-nor-L-arginine (nor-NOHA) significantly augmented the response to ACh, an effect that was partially reversed with L-arginine. No effect on tolerance to ACh was observed with L-valine, nor-valine or D,L, alpha-difluoromethylornithine (DFMO). BEC, L-NOHA and nor-NOHA elicited endothelium-independent vasorelaxation in both endothelium intact and denuded aorta while L-valine, DFMO and nor-valine did not. CONCLUSIONS AND IMPLICATIONS: BEC and L-NOHA, but not nor-NOHA, L-valine, DFMO or nor-valine, significantly reversed tolerance to ACh possibly conserving L-arginine levels and therefore increasing NO bioavailability. However, both BEC and L-NOHA caused endothelium-independent vasorelaxation in rat aorta, suggesting that these inhibitors have a role beyond arginase inhibition alone. Our data thus questions the interpretation of many studies using these antagonists as specific arginase inhibitors in the vasculature, without verification with other methods.

Human populations show reduced DNA sequence variation at the factor IX locus.

Levels and patterns of human DNA sequence variation vary widely among loci. However, some of this variation may be due to the different populations used in different studies. So far, few studies of diverse human populations have compared different genetic loci for the same samples of populations and individuals. Here, we present new polymorphism data from intron 4 of the Factor IX gene (FIX) sequenced in diverse Old World populations. An explicit comparison is made with another X-linked gene, PDHA1, for which the sampling of individuals was very similar. Despite having a similar amount of divergence from chimpanzees, as do other nuclear genes, FIX has comparatively much less DNA sequence variation among humans. Nucleotide diversity at FIX is the lowest among the existing non-Y chromosome nuclear gene datasets and is less than 10% of the diversity found at PDHA1. Estimates of effective population size based on FIX are 8,558, about half of the value obtained for PDHA1, and the time to the most recent common ancestry among human FIX gene copies (282,000 years) is one of the most recent estimates reported for human genes. Analyses presented here suggest a history for the FIX region that includes recent positive directional selection, or background, selection. The general conclusion emerging is that very large variations can exist between the histories of similar genomic regions, even when sampling differences are minimized.

Relationship of family history and outcome after breast conservation therapy in women with ductal carcinoma in situ of the breast.

PURPOSE: The purpose of this study was to evaluate the relationship between a family history of breast or ovarian cancer and outcome after breast-conserving surgery and radiation in women presenting with an initial diagnosis of ductal carcinoma in situ (DCIS) of the breast. METHODS AND MATERIALS: A total of 146 consecutive women with a pathologic diagnosis of ductal carcinoma in situ as their first diagnosis of any breast cancer were identified; 28 (19%) had a positive family history of breast or ovarian cancer in a first-degree relative, 27 (19%) had a positive family history in a second-degree relative, and 91 (62%) had no family history. Pathologic, clinical, and treatment factors, and clinical outcomes for each family history group were compared. Cosmesis and complications were recorded at each follow-up. Patients were treated between 1978 and 1995, and the median follow-up was 7.1 years. RESULTS: Patients with a positive family history in a first- or second-degree relative each had an 8% incidence of local failure at 10 years, while the negative family history group demonstrated a 16% local failure rate (p = 0.33). Overall survival at 10 years for patients with a positive family history in a first- or second-degree relative was 100% and for those with a negative family history was 91% (p = 0.08). The negative family history group had a higher median age that may account for the difference in overall survival. Cause-specific survival (CSS) was 97%, 100%, and 99%, respectively, at 10 years (p = 0.25). There were no differences in the cosmetic results or complication rates between women with a positive or negative family history. CONCLUSION: We have shown that a family history of breast and/or ovarian cancer is not associated with an adverse outcome for women treated with breast conservation therapy for DCIS. Local recurrence, cause-specific survival, overall survival, cosmesis, and complication rates were comparable to that of similarly treated women with negative family histories. Therefore, a positive family history is not a contraindication for breast conservation therapy in women with DCIS.

Molecular systematics of the old world monkey tribe papionini: analysis of the total available genetic sequences.

The phylogenetic relationships among the genera of the tribe Papionini are inferred using a taxonomic congruence approach in which gene trees derived for eight unlinked genetic sequence datasets are compared. Population genetics theory predicts that species relationships will be revealed with greater probability when the topology of gene trees from many unlinked loci are found to be congruent. The theory underlying this approach is described. Monophyly of the mangabeys is not supported by any of the gene trees; instead, they are polyphyletic with Cercocebus found to be the sister taxon to Mandrillus in five gene trees (with no conflicting trees), and Lophocebus found to be closely related to Papio and/or Theropithecus in all trees. Theropithecus and Papio are not strongly supported as sister taxa (present in one or two trees only);Lophocebus and Papio are supported as sister taxa in the majority of trees. A close relationship between Mandrillus and Papio is not supported in any of the trees.The relationships among Papio, Lophocebus, and Theropithecus cannot be resolved by congruence, probably due to the short time interval estimated between their divergences. The mtDNA COII sequences are used to estimate divergence dates within the papionins. The internode between the divergences of these species is estimated to be between 290 ka and 370 ka. Lastly, the evolution of morphological features such as long faces, suborbital facial fossae, and terrestrial skeletal adaptations is discussed.

X chromosome evidence for ancient human histories.

Diverse African and non-African samples of the X-linked PDHA1 (pyruvate dehydrogenase E1 alpha subunit) locus revealed a fixed DNA sequence difference between the two sample groups. The age of onset of population subdivision appears to be about 200 thousand years ago. This predates the earliest modern human fossils, suggesting the transformation to modern humans occurred in a subdivided population. The base of the PDHA1 gene tree is relatively ancient, with an estimated age of 1.86 million years, a late Pliocene time associated with early species of Homo. PDHA1 revealed very low variation among non-Africans, but in other respects the data are consistent with reports from other X-linked and autosomal haplotype data sets. Like these other genes, but in conflict with microsatellite and mitochondrial data, PDHA1 does not show evidence of human population expansion.

Nuclear gene trees and the phylogenetic relationships of the mangabeys (Primates: Papionini).

Phylogenetic relationships of mangabeys within the Old World monkey tribe Papionini are inferred from analyses of nuclear DNA sequences from five unlinked loci. The following conclusions are strongly supported, based on congruence among trees derived for the five separate gene regions: (1) mangabeys are polyphyletic within the Papionini; (2) Cercocebus is the sister taxon to the genus Mandrillus; and (3) Lophocebus belongs to a clade with Papio and Theropithecus, with Papio as its most likely sister taxon. Morphologically based phylogenies positing mangabey monophyly were evaluated by mapping the sequences for each locus on these trees. The data seem to fit these trees poorly in both maximum-parsimony and likelihood analyses. Incongruence among nuclear gene trees occurred in the interrelationships among Lophocebus, Papio, and Theropithecus. Several factors that may account for this incongruence are discussed, including sampling error, random lineage sorting, and introgression.

Concurrent chemotherapy and radiation for breast conservation treatment of early-stage breast cancer.

PURPOSE: The optimal sequencing of chemotherapy and radiation therapy in patients with early-stage breast cancer undergoing breast-conservation treatment remains controversial. The purpose of this study is to evaluate the outcome of patients treated with one specific sequence of concurrent chemoradiation followed by additional chemotherapy. METHODS: Between 1977 and 1992, 210 patients with stage I and II breast cancer underwent lumpectomy and axillary lymph node dissection followed by treatment with concurrent chemotherapy and radiation therapy, followed by further chemotherapy. Chemotherapy consisted of two 28-day cycles of CF (oral cyclophosphamide, 100 mg/m2 day 1 to 14, and intravenous 5-fluorouracil, 600 mg/m2 days 1 and 8) during radiation therapy, followed in general by six cycles of CMF (CF doses as above plus intravenous methotrexate 40 mg/m2 days 1 and 8) after the completion of radiation therapy. Fifty patients also received hormonal therapy, predominantly tamoxifen. One hundred ten patients had clinical T1 lesions, and 100 had T2 lesions. Fifty-three patients were pathologic N0, and 157 patients were pathologic N1 (123 patients had one to three positive nodes, and 34 patients had four or more positive nodes). Median follow-up for node-negative patients (5.2 years) is shorter than for node-positive patients (7.6 years). Therefore, outcome is reported at 5 and 10 years for node-positive patients but only at 5 years for node-negative patients. RESULTS: For node-positive patients, outcomes at 5 and 10 years, respectively, were 86% and 70% for overall survival, 78% and 67% for no evidence of disease survival, and 82% and 69% for freedom from distant metastases. For node-negative patients, outcomes at 5 years were 94% for overall survival, 94% for no evidence of disease survival, and 94% for freedom from distant metastases. Pathologic nodal status was predictive of outcome after treatment. Local failure in the treated breast was 5% at 5 years and 13% at 10 years for all patients. CONCLUSIONS: Concurrent CF with radiation therapy followed by six cycles of CMF after radiation therapy results in excellent survival, freedom from distant metastases, and local control for both node-negative and node-positive patients. This regimen of concurrent chemotherapy and radiation therapy is one option for sequencing, and it avoids the delays in administration of either modality that are associated with other sequencing regimens.

The effects of sequence and type of chemotherapy and radiation therapy on cosmesis and complications after breast conservation therapy.

PURPOSE: Chemotherapy plays an increasingly important role in the treatment of both node-negative and node-positive breast cancer patients, but the optimal sequencing of chemotherapy and radiation therapy is not well established. The purpose of this study is to evaluate the interaction of sequence and type of chemotherapy and hormonal therapy given with radiation therapy on the cosmetic outcome and the incidence of complications of Stage I and II breast cancer patients treated with breast-conserving therapy. METHODS AND MATERIALS: The records of 1053 Stage I and II breast cancer patients treated with curative intent with breast-conserving surgery, axillary dissection, and radiation therapy between 1977-1991 were reviewed. Median follow-up after treatment was 6.7 years. Two hundred fourteen patients received chemotherapy alone, 141 patients received hormonal therapy alone, 86 patients received both, and 612 patients received no adjuvant therapy. Patients who received chemotherapy +/- hormonal therapy were grouped according to sequence of chemotherapy: (a) concurrent = concurrent chemotherapy with radiation therapy followed by chemotherapy; (b) sequential = radiation followed by chemotherapy or chemotherapy followed by radiation; and (c) sandwich = chemotherapy followed by concurrent chemotherapy and radiation followed by chemotherapy. Compared to node negative patients, node-positive patients more commonly received chemotherapy (77 vs. 9%, p < 0.0001) and/or hormonal therapy (40 vs. 14%, p < 0.0001). Among patients who received chemotherapy, the majority (243 patients) received concurrent chemotherapy and radiation therapy with two cycles of cytoxan and 5-fluorouracil (5-FU) administered during radiation followed by six cycles of chemotherapy with cytoxan, 5-fluorouracil and either methotrexate (CMF) or doxorubicin(CAF). For analysis of cosmesis, patients included were relapse free with 3 years minimum follow-up. RESULTS: The use of chemotherapy had an adverse effect on cosmetic outcome compared to no chemotherapy, which was of borderline significance at 3 years (92% excellent or good cosmetic outcome vs. 96% respectively, p = 0.057); however, cosmesis was not different at 5 years (91 vs. 93% respectively, p = 0.67). Cosmesis was not significantly different between patients treated sequentially and those treated concurrently (3 year: 87 vs. 93% respectively, p = 0.33), nor was it different between patients who received CMF vs. CAF (3 year: 92 vs. 93% respectively, p = 0.89). Hormonal therapy did not influence cosmetic outcome (p = 0.78). The incidence of Grade 4 or 5 arm edema (> or = 2 cm difference in arm circumference) was 2% without chemotherapy vs. 8% with chemotherapy (p = 0.00002). However, the incidence of arm edema was not affected by sequencing or type of chemotherapy (all p > or = 0.52). Patients treated sequentially had a 10% incidence of Grade 4 or 5 arm edema vs. 7% in the patients treated concurrently (p = 0.52). The incidence was 7 vs. 9% in patients treated with CMF vs. CAF (p = 0.73). The incidence of clinical pneumonitis and rib fracture was not influenced by use of chemotherapy, sequence of chemotherapy or use of hormonal therapy (all p > or = 0.06). CONCLUSIONS: Chemotherapy can be given concurrently with radiation therapy in the treatment of Stage I and II breast cancer with breast-conserving therapy without seriously compromising cosmetic outcome or incidence of complications compared to patients receiving other sequences of chemotherapy. Hormonal therapy did not affect cosmesis or complications. The chemotherapeutic regimen of cytoxan and 5-FU concurrent with radiation therapy followed by more chemotherapy is one reasonable option for breast conservation therapy in patients requiring chemotherapy.

Human gross anatomy: a crucial time to encourage respect and compassion in students.

We suggest four ways in which human gross anatomy instructors can reinforce respect and compassion in students. First, encourage respectful language in the laboratory. The term "donor" should be used instead of "cadaver" or "corpse" in referring to the donated body because this promotes appreciation for the students' first "patient." Second, provide the students with the actual name, age, history, and likely cause of death of the donor so that they more fully appreciate the donor as having once been a living human being. Third, prompt students to explore feelings and discuss topics stimulated by the intense experience of human dissection. Suggested topics include the students' feelings about dissecting a human being, the difficulty in deciding to donate one's body, the central importance of anatomy to a medical practitioner's role, and the historical development of the study of anatomy. Fourth, hold a memorial ceremony, in which both students and faculty participate, as a positive closure to an emotionally and intellectually intense course. Additionally, a ceremony reinforces salutary values in students, enhances social bonding among students, and encourages their appreciation of various cultural and religious beliefs. These methods introduce a new dimension of experience for anatomy students. We have developed these methods in response to what we view as a negative trend in the medical profession in which health care becomes technical and patients become objects. It is our role as faculty to reinforce respectful and compassionate attitudes in medical students from the very beginning.

Case report: acute focal bacterial pyelonephritis (lobar nephronia)--presentation as a palpable abdominal mass.

Acute lobar nephronia, or focal pyelonephritis, is an uncommon form of renal infection with a distinct computerized tomographic appearance. A patient is presented with lobar nephronia characterized by fever, flank pain, urosepsis, and painful abdominal mass. Differentiating this condition from abscess or other renal mass is important, because the treatment of lobar nephronia is nonsurgical. The infection responds to antibiotic therapy.

Roundup: extractors. Eight manufacturers of extractors provide details about their systems.

Choosing an extractor for a specific set of plant conditions can be complicated and costly, if you make the wrong purchasing decision. Extractors come in two types: centrifugal and compression, but there are numerous models of each. Here, eight manufacturers of extractors provide details about their systems.

High-tech equipment--present and future options for rental operators.

U.S. and European laundry equipment manufacturers are striving to gain efficiencies with high technology. They are well aware that operators want to use resources--including energy, water, labor, and merchandise--better. Also, meaningful information about plant operations is becoming a top priority. Many high-tech options are available now and others are in the works to carry this industry into the next century.

Rapid MIC testing with the sensititre autoreader.

Automated microdilution MIC results, obtained with the Autoreader (Sensititre, Inc., Salem, N.H.) following 5 h of incubation, were compared with manually read, concurrent control MICs following 18 h of incubation in a three-laboratory comparative study. A total of 704 members of the family Enterobacteriaceae or similar gram-negative organisms were tested against 17 antimicrobial agents. Autoreader MICs were within 1 doubling dilution of control values in 92.9% of instances. Discrepancies of +/- 2 doubling dilutions and +/- 3 or greater doubling dilutions were noted in 4.5 and 2.6%, respectively, of the 7,687 drug-organism combinations analyzed. The majority of errors occurred when beta-lactam antimicrobial agents were tested with a variety of different species. MICs at 5 h, when Pseudomonas aeruginosa was used, were possible in only half the isolates tested and yielded data on only a limited number of drugs in the remaining instances. Excluding results obtained with penicillin and ampicillin, which were uniformly poor, Staphylococcus aureus Autoreader values were within +/- 1 doubling dilution of control values in 93.6% of instances, 5.4% varied by +/- 2 dilutions, and only 1% of test values by +/- 3 or more dilutions from control values for 82 isolates tested against nine antimicrobial agents. Of eight additional S. aureus isolates tested that were resistant to methicillin, only one was read correctly by the Autoreader, with results on the remaining seven appearing as either insufficient growth or as total resistance to all drugs tested. Interlaboratory reproducibility was excellent for selected isolates of S. aureus and gram-negative bacilli. The accuracy of the Sensititre Autoreader MIC results was comparable to that of other same-day quantitative systems for members of the family Enterobacteriaceae and S. aureus, while the economic and procedural advantages of the broth microdilution method was maintained.

Conformationally restricted inhibitors of angiotensin converting enzyme: synthesis and computations.

A series of inhibitors of angiotensin converting enzyme (ACE, dipeptidyl carboxypeptidase, EC 3.4.15.1) is described which addresses certain conformational aspects of the enzyme-inhibitor interaction. In this study the alanylproline portion of the potent ACE inhibitor enalaprilat (2) is replaced by a series of monocyclic lactams containing the required recognition and binding elements. In order to more fully assess the lactam ring conformations and the key backbone angle psi as defined in 3 with respect to possible enzyme-bound conformations, a series of model lactams was investigated with use of molecular mechanics. The results point to a correlation between inhibitor potency (IC50) and the computed psi angle for the lowest energy conformation of the model compounds. Thus the psi angle as defined in 3 is an important determinant in the binding of inhibitors to ACE. The inhibition data in conjunction with the computational data have served to define a window of psi angles from 130 degrees to 170 degrees which seems to be acceptable to the ACE active site.

Automated reading of MIC microdilution trays containing fluorogenic enzyme substrates with the Sensititre Autoreader.

The Sensititre Autoreader is a microcomputer-driven instrument capable of automatically reading antimicrobial susceptibility microdilution trays. The instrument measures the fluorescence liberated by bacterial enzymatic activity on fluorogenic substrates as an indicator of growth in each well. A mathematical algorithm converts the fluorescent signals from an antimicrobial dilution series to an MIC endpoint. A three-center study evaluated the performance of the Autoreader in comparison with MIC determined visually in a duplicate set of control plates lacking fluorogenic substrate. Among 828 isolates of gram-negative bacilli tested against 17 antimicrobial agents, Autoreader 18-h MIC were within +/- 1 twofold dilution of control MIC values (agreement) in 95.3% of instances. In 3.5% of the instances, Autoreader values occurred +/- 2 half-step dilutions from control values (minor discrepancy), and in only 1.2% of instances did Autoreader values deviate from control values by greater than +/- 2 dilution steps (major discrepancy). Agreement, minor discrepancies, and major discrepancies were noted among 148 gram-positive cocci tested against 11 antimicrobial agents in 93.5, 4.8, and 1.7% of the instances, respectively. Over half of the major discrepancies noted with gram-negative bacilli occurred with Proteus mirabilis-beta-lactam combinations, a problem that was resolved when a lower initial inoculum was used. Inter-and intralaboratory reproducibility was excellent. Standard Sensititre susceptibility trays may be instrument read at 18 h reproducibly and accurately with only slight modification of conventional procedures to include fluorogenic enzyme substrates in the incubation broth.