Nb K-edge x-ray absorption investigation of the pressure induced amorphization in A-site deficient double perovskite La1/3NbO3

Nb K-edge x-ray absorption spectroscopy is utilized to investigate the changes in the local structure of the A-site deficient double perovskite La1/3NbO3 which undergoes a pressure induced irreversible amorphization. EXAFS results show that with increasing pressure up to 7.5 GPa, the average Nb-O bond distance decreases in agreement with the expected compression and tilting of the NbO6 octahedra. On the contrary, above 7.5 GPa, the average Nb-O bond distance show a tendency to increase. Significant changes in the Nb K-edge XANES spectrum with evident low energy shift of the pre-peak and the absorption edge is found to happen in La1/3NbO3 above 6.3 GPa. These changes evidence a gradual reduction of the Nb cations from Nb(5+) towards Nb(4+) above 6.3 GPa. Such a valence change accompanied by the elongation of the average Nb-O bond distances in the octahedra, introduces repulsion forces between non-bonding adjacent oxygen anions in the unoccupied A-sites. Above a critical pressure, the Nb reduction mechanism can no longer be sustained by the changing local structure and amorphization occurs, apparently due to the build-up of local strain. EXAFS and XANES results indicate two distinct pressure regimes having different local and electronic response in the La1/3NbO3 system before the occurence of the pressure induced amorphization at  ∼14.5 GPa.

X-ray microdiffraction, TEM characterization and texture analysis of human dentin and enamel

Human tooth is a complex bioceramic composite, which consists of enamel, dentin and the interface, the dentin-enamel junction (DEJ). The crystal properties and ultrastructure of the inorganic phase through the thickness of healthy human molar teeth were investigated using X-ray microdiffraction (μXRD), electron diffraction and transmission electron microscopy (TEM) techniques. The XRD data were analysed using the Le Bail profile fitting approach. The size and the texture of the crystallites forming enamel and dentin in the crown part of teeth were measured using both techniques and then compared. Results showed that the thickness of dentin crystallites was found to decrease towards the DEJ, whereas the thickness of the enamel crystallites increased from the DEJ towards the outer layers. It was demonstrated that enamel exhibited an increase of texture in 002 lattice planes from the DEJ towards the outer layers. Texture was also detected in 102 lattice planes. The texture effect in 002 planes at the scale of less than 1 μm was also demonstrated in dentin. The variation of lattice parameters as a function of the position within the thickness of dentin and enamel was also observed. The values of the nonuniform microstrain in the dentin and enamel crystallites were from 1.40 × 10(-6) % to 4.44 × 10(-5) %. The good correlation between XRD and TEM indicated that μXRD is a useful technique to study crystallography and microstructure of heterogeneous enamel and dentin. The observed gradient characteristics of texture and crystallite size in enamel and dentin maybe an evolutionary outcome to resist wear and fracture, thereby contributing to the excellent mechanical properties of teeth.

Elastic anomalies associated with transformation sequences in perovskites: II. The strontium zirconate-titanate Sr(Zr,Ti)O(3) solid solution series

The sequence of phase transitions due to octahedral tilting across the Sr(Zr,Ti)O(3) solid solution series has been investigated by resonant ultrasound spectroscopy at high and low temperatures using ceramic samples. The elastic behaviour associated with phase transitions as a function of composition in Sr(Zr,Ti)O(3) at room temperature is proposed to be analogous to that as a function of temperature in SrZrO(3), with the [Formula: see text] transition at SrZr(0.57)Ti(0.43)O(3), [Formula: see text] at SrZr(0.35)Ti(0.65)O(3), and [Formula: see text] at SrZr(0.05)Ti(0.95)O(3). Changes in elastic constants and acoustic dissipation with temperature have been analysed for samples across the compositional range. The intermediate phases, I4/mcm and what is assumed to be Imma, appear to have stability fields across the full compositional range and both show large dissipation effects, most probably due to twin wall mobility. In contrast, the Zr-rich Pnma phase, which should contain transformation twin walls, is an unexpectedly stiff and non-dissipating material, similar to the high temperature and/or Ti-rich [Formula: see text] phase. In the case of Pnma, this is attributed to coupling between the two order parameters, which could impede relaxation responses to an applied stress. The [Formula: see text] structure is a classically stiff cubic perovskite and no transformation-related dissipation processes are expected.

Effect of Structure and Thermodynamic Stability on the Response of Lanthanide Stannate Pyrochlores to Ion Beam Irradiation

The lanthanide stannates, Ln2Sn2O7, Ln=La-Lu and Y, have the isometric pyrochlore structure, A2B2O7, and their structural properties have been refined by Rietveld analysis of powder neutron and synchrotron X-ray diffraction data. In this study, the enthalpies of formation of selected stannate pyrochlores, Ln=La, Nd, Sm, Eu, Dy, and Yb, were measured by high-temperature oxide melt solution calorimetry. Their radiation response was determined by 1 MeV Kr2+ ion irradiation combined with in situ TEM observation over the temperature range of 25 to 1000 K. The enthalpy of formation from binary oxides of stannate pyrochlores became more endothermic (from -145 to -40 kJ/mol) as the size of the lanthanide in the A-site decreases. A more exothermic trend of the enthalpy of formation was observed in stannate pyrochlores with larger lanthanide ions, particularly La, possibly as a result of increased covalency in the Sn-O bond. In contrast to lanthanide titanate pyrochlores, Ln2Ti2O7, that are generally susceptible to radiation-induced amorphization and zirconate pyrochlores, Ln2Zr2O7, that are generally resistant to radiation-induced amorphization, the lanthanide stannate pyrochlores show a much greater variation in their response to ion irradiation. La, Nd, and Gd stannates experience the radiation-induced transformation to the aperiodic state, and the critical amorphization temperatures are approximately 960, 700, and 350 K, respectively. Y and Er stannate pyrochlores cannot be amorphized by ion beam irradiation, even at 25 K, and instead disorder to a defect fluorite structure. Comparison of the calorimetric and ion irradiation data for titanate, zirconate, and stannate pyrochlores reveals a strong correlation among subtle changes in crystal structure with changing composition, the energetics of the disordering process, and the temperature above which the material can no longer be amorphized. In summary, as the structure approaches the ideal, ordered pyrochlore structure, radiation-induced amorphization is more easily attained. This is consistent with an increasingly exothermic trend in the enthalpies of formation of pyrochlores from the oxides, that is, the greater the thermochemical stability of the pyrochlore structure, the more likely it will be amorphized upon radiation damage rather than recover to a disordered fluorite structure.

Determination of the structures of antiinflammatory copper(II) dimers of indomethacin by multiple-scattering analyses of X-ray absorption fine structure data

Copper K-edge X-ray absorption spectroscopic (XAS) measurements were recorded for the veterinary antiinflammatory Cu(II) complexes of indomethacin (1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indole-3-acetic acid = IndoH), of the general formula [Cu(2)(Indo)(4)L(2)] (L = N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), N-methylpyrrolidone (NMP), and water), and [Cu(2)(OAc)(4)(OH(2))(2)] at room temperature and 10 K. The bond lengths and bridging O-C-O angles of the dimeric Cu(II) cage (Cu(2)O(10)C(8)) obtained from the multiple-scattering (MS) fitting of the X-ray absorption fine structure (XAFS) using a centrosymmetric model of [Cu(2)(Indo)(4)(DMF)(2)] gave Cu.Cu = 2.62(2) A, mean Cu-O(Ac) = 1.95(2) A, Cu-O(L) = 2.15(2) A, bridging O-C-O = 125(1) degrees, Cu displacement from plane 0.19 A compared with the XRD data Cu.Cu = 2.630(1) A, mean Cu-O(Ac) = 1.959 A, Cu-O(L) = 2.143(5) A, bridging O-C-O angles = 123.2(5) degrees, Cu displacement from plane 0.20 A. The excellent agreement between the XAFS- and XRD-derived data allowed the structures of related [Cu(2)(Indo)(4)L(2)] (L = DMA, NMP) complexes to be determined. All display a similar Cu(2)O(10)C(8) coordination geometry, which is independent of the nature of the axial ligand. While XAFS analysis of [Cu(2)(Indo)(4)(OH(2))(2)] and [Cu(2)(OAc)(4)(OH(2))(2)] indicates a coordination geometry similar to that of [Cu(2)(Indo)(4)L(2)] (L = DMF, DMA, NMP), removal of symmetry restraints in the MS model is required to obtain axial bond lengths comparable to those derived in the XRD structures of the acetate complex. For the Indo complex, the fitted bond lengths with the lower symmetry model give a mean Cu-L(OH2) bond distance within experimental errors of the value for [Cu(2)(Indo)(4)(DMSO)(2)] (2.16(2) A) (XRD). The difficulty in refining the Cu-O(OH2) distance of [Cu(2)(OAc)(4)(OH(2))(2)] and [Cu(2)(Indo)(4)(OH(2))(2)] using a centrosymmetric MS model is attributed to a symmetry reduction due to hydrogen-bonding effects characteristic of the aqua adducts, as is observed in the XRD structure of the acetate complex.

Aging and cancer

The world's population is aging. Older age is associated with an increase in the incidence of cancer, especially cancer of the breast, lung, prostate, and colon. The management of older patients with cancer is biased by the simple fact of their chronologic age. Underscreening, understaging, less aggressive therapy, lack of participation in clinical trials, or no treatment at all reflect this bias. Although an age-related reduction in the physiologic function of many organs occurs with age, these are not contraindications to treatment with surgery, radiation therapy, or chemotherapy. Chronologic age alone should not be used as a guide for cancer management. Rather, physiologic function or existence of comorbid conditions should be major factors in determining treatment. As a result of the impending need for improved cancer management in older persons, a new subspecialty is evolving: geriatric oncology. This field stresses an important interaction between geriatricians and oncologists, development of research directed at the problems of cancer in older persons, and education at all levels with respect to cancer prevention, cancer detection, and cancer therapy. Physicians and oncologists need to be prepared for the projected increase of cancer in older persons.

Syntheses and characterization of anti-inflammatory dinuclear and mononuclear zinc indomethacin complexes. Crystal structures of [Zn2(indomethacin)4(L)2] (L = N,N-dimethylacetamide, pyridine, 1-methyl-2-pyrrolidinone) and [Zn(indomethacin)2(L1)2] (L1 = ethanol, methanol)

The syntheses and spectral and structural characterizations of Zn(II) indomethacin [1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indole-3-acetic acid = IndoH] complexes, as different solvent adducts, have been studied. The complexes are unusual in that both monomeric and dimeric complexes are formed and that this is the first example of the same carboxylato ligand binding via both carboxylate oxygen atoms in monomeric and dimeric Zn(II) complexes. The crystal structures of Zn-Indo complexes with N,N-dimethylacetamide (DMA), pyridine (Py), 1-methyl-2-pyrrolidinone (NMP), EtOH, and MeOH as solvent ligands, [Zn2(Indo)4(DMA)2].2DMA, 1, [Zn2(Indo)4(Py)2].2H2O, 2b, [Zn2(Indo)4(NMP)2], 3, cis-[Zn(Indo)2(EtOH)2], 4, and cis-[Zn(Indo)2(MeOH)2], 5, were determined. Complexes 1, 2b, and 3 crystallize in the triclinic space group P1 (No. 2): a = 13.628(2) A, b = 17.462(2) A, c = 11.078(1) A, alpha = 99.49(1) degrees, beta = 108.13(1) degrees, gamma = 110.10(1) degrees for 1; a = 13.347(3) A, b = 16.499(5) A, c = 10.857(1) A, alpha = 99.48(2) degrees, beta = 108.25(2) degrees, gamma = 106.24(2) degrees for 2; a = 14.143(3) A, b = 14.521(2) A, c = 11.558(2) A, alpha = 109.07(1) degrees, beta = 90.80(2) degrees, gamma = 116.40(1) degrees for 3. The three complexes exhibit dinuclear paddle-wheel structures with a Zn...Zn distance of 2.9686(6) A, Zn-ORCOO distances of 2.035(2)-2.060(2) A, and a Zn-ODMA distance of 1.989(2) A in 1, a Zn...Zn distance of 2.969(1) A, Zn-ORCOO distances of 2.020(3)-2.049(3) A, and a Zn-NPy distance of 2.036(3) A in 2, and a Zn...Zn distance of 2.934(1) A, Zn-ORCOO distances of 2.009(3)-2.051(3) A, and a Zn-ONMP distance of 1.986(3) A in 3. In these cases, the zinc ions are offset along the z direction such that the L-Zn...Zn-L moiety is nonlinear, unlike the Cu analogues. Each Zn has a square-pyramidal geometry bridged by four carboxylato ligands in the basal plane with the solvent ligands containing an O- or N-donor atom at the apex. Complexes 4 and 5 are isostructural, with space group C2/c (No. 15). For 4, a = 30.080(2) A, b = 5.3638(6) A, c = 24.739(2) A, beta = 90.342(7) degrees, and for 5, a = 29.419(2) A, b = 5.320(2) A, c = 24.461(2) A, beta = 90.840(4) degrees. The Zn resides on a 2-fold axis and the complexes have a distorted cis octahedral structure with Zn-ORCOO bond lengths of 2.183(3) and 2.169(3) A, a Zn-OEtOH bond length of 2.015(3) A in 4, Zn-ORCOO bond lengths of 2.195(2) and 2.151(2) A, and a Zn-OMeOH bond length of 2.022(3) A in 5.

A physician's point of view

What follows are the perceptions of two individuals-a patient and a highly respected medical oncologist who did not participate in the care of this patient but read the patient's essay. We encourage readers to share their thoughts about these essays in correspondence. Barrie E. Cassileth, Ph.D. Department of Integrative Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York A. Bernard Ackerman, M.D. Ackerman Academy of Dermatopathology, New York, New York Copyright 2000 American Cancer Society.

Passive transfer of antiserum specific for immunogens derived from a nontypeable Haemophilus influenzae adhesin and lipoprotein D prevents otitis media after heterologous challenge

We recently determined that passive transfer of serum directed against a synthetic peptide called LB1 or a recombinant fusion protein immunogen [LPD-LB1(f)(2,1,3)] could prevent otitis media after challenge with a homologous nontypeable Haemophilus influenzae (NTHI) isolate. NTHI residing in the nasopharynx was rapidly cleared from this site, thus preventing it from ascending the eustachian tube and inducing otitis media in chinchillas compromised by an ongoing viral upper respiratory tract infection. While LB1 is based solely on one NTHI adhesin, the latter immunogen, LPD-LB1(f)(2,1,3), was designed to incorporate two NTHI antigens shown to play a role in the pathogenesis of otitis media; lipoprotein D (LPD) and the P5-homologous fimbrin adhesin. The design of LPD-LB1(f)(2,1,3) also accommodated for the recently demonstrated existence of three major groupings, based on amino acid sequence diversity, in the third surface-exposed region of P5-fimbrin. LPD-LB1(f)(2,1,3) was thus designed to potentially confer broader protection against challenge by diverse strains of NTHI. Chinchillas were passively immunized here with serum specific for either LB1 or for LPD-LB1(f)(2,1,3) prior to challenge with a member of all three groups of NTHI relative to diversity in region 3. The transferred serum pools were also analyzed for titer, specificity, and several functional activities. We found that both serum pools had equivalent ability to mediate C'-dependent killing and to inhibit adherence of NTHI strains to human oropharyngeal cells. When passively transferred, both serum pools significantly inhibited the signs and incidence of otitis media (P </= 0.01) induced by any of the three challenge isolates. Despite providing protection against disease, the ability of these antisera to induce total eradication of NTHI from the nasopharynx was not equivalent among NTHI groups. These data thus suggested that while early, complete eradication of NTHI from the nasopharynx was highly protective, reduction of the bacterial load to below a critical threshold level appeared to be similarly effective.

Hodgkin's disease survival by stage and age

OBJECTIVE

Prior reports on Hodgkin's disease have suggested a biologic behavior difference between young and old patients. A study of 35,033 patients could confirm that older patients do not do as well as young patients regardless of age.

METHODS

The National Cancer Data Base provided data from U.S. tumor registries on 35,033 patients newly diagnosed with Hodgkin's disease from 1985 through 1994. For analysis the patients were divided into two time periods, 1985-1989 and 1990-1994. The earlier period provided survival data to assess the impact of age and stage.

RESULTS

The overall disease-specific, 5-year survival rate for the 1985-1989 period was 84.9%. For stages I and II, it reached almost 90%. For both observed survival based on all deaths and disease-specific survival, the duration of survival decreased with increasing age. This decrease with age occurred for all stages of the disease.

CONCLUSIONS

The data reflect the actual status of management of Hodgkin's disease in the United States rather than the best attainable results. The decreasing survival with increasing age and in all stages further supports the concept of a difference in biologic behavior of Hodgkin's disease associated with age.

Protection against development of otitis media induced by nontypeable Haemophilus influenzae by both active and passive immunization in a chinchilla model of virus-bacterium superinfection

Three separate studies, two involving active-immunization regimens and one involving a passive-transfer protocol, were conducted to initially screen and ultimately more fully assess several nontypeable Haemophilus influenzae outer membrane proteins or their derivatives for their relative protective efficacy in chinchilla models of otitis media. Initial screening of these antigens (P5-fimbrin, lipoprotein D, and P6), delivered singly or in combination with either Freund's adjuvant or alum, indicated that augmented bacterial clearance from the nasopharynx, the middle ears, or both anatomical sites could be induced by parenteral immunization with P5-fimbrin combined with lipoprotein D, lipoprotein D alone, or the synthetic chimeric peptide LB1 (derived from P5-fimbrin), respectively. Data from a second study, wherein chinchillas were immunized with LB1 or lipoprotein D, each delivered with alum, again indicated that clearance of nontypeable H. influenzae could be augmented by immunization with either of these immunogens; however, when this adjuvant was used, both antibody titers in serum and efficacy were reduced. A third study was performed to investigate passive delivery of antisera directed against either LB1, lipoprotein D, nonacylated lipoprotein D, or a unique recombinant peptide designated LPD-LB1(f)2,1,3. The last three antiserum pools were generated by using the combined adjuvant of alum plus monophosphoryl lipid A. Passive transfer of sera specific for LB1 or LPD-LB1(f)2,1,3 to adenovirus-compromised chinchillas, prior to intranasal challenge with nontypeable H. influenzae, significantly reduced the severity of signs and incidence of otitis media which developed (P </= 0.001). Collectively, these data indicate the continued merit of further developing LB1 and LPD-LB1(f)2,1,3 as components of vaccines for otitis media.

Uracil mustard revisited

BACKGROUND

A patient with diffuse large cell lymphoma who had a complete response lasting 35 years following a 3-day course of uracil mustard stimulated a recall review of patients treated with this oral alkylating agent.

METHODS

Records of patients treated with uracil mustard between 1958 and 1970 were reviewed. A current histologic review according to the International Formulation was performed when possible. Total doses of uracil mustard were similar to those of mechlorethamine, although there were variations in the dose schedule.

RESULTS

Employing criteria used over 25 years ago to evaluate patients' responses, the overall regression rate for 94 non-Hodgkin lymphoma patients was 69.2% (complete response [CR] 23.4%). Of 62 patients with Hodgkin disease, 69.4% responded (CR 9.7%). For 39 patients with chronic lymphatic leukemia, the combined complete and partial response rate was 74% (CR 7.7%). Thrombocytopenia was the primary toxicity.

CONCLUSIONS

Uracil mustard is an unmarketed, inexpensive oral alkylating agent that has been effective in the treatment of patients with lymphoma, chronic lymphatic leukemia, and thrombocythemia. Perhaps it should be reevaluated.

Medical oncology: its origin, evolution, current status, and future

BACKGROUND

Over the last 26 years, the subspecialty of medical oncology has been evolving, and in the process bringing to the community improved oncologic management. During this evolution, guidelines for training new members of the subspecialty have been developed, and these have been heralded as important strides forward in medical education. Continual adjustment to new technology and changing population needs represent challenges for the future.

METHODS

The steps in the development of this subspecialty, which are documented in educational publications, are reviewed in this article.

RESULTS

Medical oncology evolved because of the introduction of multiple new cancer therapies and an awareness of the need of patients with cancer for continual care, from diagnosis to the end-of-life phase. Together, certified medical oncologists represent the third largest of the current subspecialties of internal medicine. Training guidelines and the needs of the work force are being continually assessed in an effort to maintain an important future for these specialists.

CONCLUSIONS

Medical oncologists are cancer specialists who are not in competition with primary care physicians, but are instead supportive. By serving as principal caregivers (those subspecialists who provide most of a patient's health care needs), and by paying increasing attention to older patients with cancer, medical oncologists will remain in demand.

Adjuvant therapy of breast cancer--an overview

Adjuvant therapy in the treatment of breast cancer commonly refers to therapies that supplement primary treatment, traditionally mastectomy and, more recently, breast-conserving surgery. The present paper examines the evolution of systemic therapies and radiotherapy in their role as adjuvants to mastectomy, and offers a brief description of current treatment regimens for early and locally advanced disease.

The National Cancer Data Base report on Hodgkin's disease for 1985-1989 and 1990-1994

BACKGROUND

A national survey of the management of Hodgkin's disease patients based on cases in the National Cancer Data Base (NCDB) provides a basis for evaluating the results of educational and therapeutic programs. These patients are believed to have been drawn from all nationalities, native and migrant, and were reported by hospital cancer registries throughout the United States, including large and small community hospitals, university and other teaching hospitals, military and Veterans Administration (VA) hospitals, and National Cancer Institute (NCI)-Designated Centers.

METHODS

Data submitted voluntarily to the NCDB were used to determine trends in patterns of patient care across time. For the period 1985-1994, data from 35,033 patients with newly diagnosed Hodgkin's disease were analyzed and separated into two time periods, 1985-1989 and 1990-1994.

RESULTS

Data were analyzed with respect to age, race, histology, stage, treatment, and survival. The majority of patients (83.6%) were white, the age group with the highest incidence was 20-29 years, and nodular sclerosis was the most common histologic type. Staging was reported as a combination of clinical and pathologic stage ("combined stage"). The number of cases of reported stage increased from 51.7% for the years 1985-1989 to 75.7% for the years 1990-1994. Radiation therapy was used primarily to treat patients in Stages I and II, although the overall use of radiotherapy declined by 10% in the later period. The overall observed 5-year survival rate was 83.2%, and the disease specific observed survival rate was 84.9%. Stage for stage, survival was better for younger patients and poorer for older patients.

CONCLUSIONS

The survey reflects the actual management of Hodgkin's patients disease. The reported cases for 1994 represent 60.6% of the estimated occurrences for that year in the U.S. There has been a significant improvement in the frequency of use of the staging system. A continuing increase in survival for patients with Hodgkin's disease is occurring. This method of studying disease management provides a measure of educational efforts and guides to developmental research.

Familial hearing loss and cisplatin therapy

Familial high-tone hearing loss in males is a recessive trait often unrecognized. Cisplatin chemotherapy may be associated with hearing loss. A review was made of audiograms in 85 patients with testicular carcinoma prior to cisplatin chemotherapy to determine the extent of preexisting familial hearing loss. Clinical histories defined patients exposed to high noise levels and other common causes of hearing loss. Audiometric findings were classified according to normal hearing or mild, moderate, and severe hearing impairment. Pretreatment audiograms were normal in 51 patients and abnormal in 19 patients with histories of high-level noise exposure, and in 15 patients with high-frequency hearing loss there was no history of noise exposure, ear infection, or other potential causes of hearing loss. These last 15 patients were judged to have recessive familial hearing loss. Awareness of familial hearing loss is important in male patients in whom cisplatin chemotherapy is planned. Pretreatment hearing assessment, including audiograms, is recommended for such male patients.

Serial in vivo passage of HIV-1 infection in Macaca nemestrina

In an earlier study we found that pigtailed macaques (Macaca nemestrina) that were experimentally infected with human immunodeficiency virus type 1 (HIV-1) initially became viremic and seroconverted, but HIV-1 replication diminished markedly over time. In an attempt to develop a longer term pathogenic model, blood from HIV-1-infected macaques was serially transfused into three groups of naive macaques. Transfer was successful through two transfusions as shown by repeated virus isolations and confirmed by the development of cell-free plasma viremia and by seroconversion. Three to five weeks after transfusion, plasma levels of HIV-1 RNA from several macaques in the first two groups exceeded those of the initially inoculated macaques. However, animals in the third group had diminished RNA levels, were virus culture negative, and did not seroconvert. Sequence analyses of env-region clones from infected animals revealed only minimal changes over the course of the passages. These results confirm HIV-1 replication in M. nemestrina during the acute phase of infection. However, adaptation of HIV-1 to a macaque-pathogenic variant did not occur during serial passage, possibly because the animals were able to restrict HIV-1 replication below a level required for a pathogenic variant to emerge. Whether such containment is a function of the host's immune response or a virus cell incompatibility remains to be determined.

Medical oncology as a discipline

Medical oncology has become a major subspecialty discipline of internal medicine within only 25 years. The special skill of oncologists is judgement in matters relating to cancer. This specialty brought the necessary expertise for cancer management into the community, improved care of patients with cancer worldwide, and provided a significant impact on cancer education and cancer research. Current manpower needs have been met but the ultimate in desired services are not apparent. Attempts to merge hematology and oncology are unwarranted. The future for medical oncology will be challenging, especially to meet the expanding needs of geriatric oncology.

Role of splenectomy in gastric cancer surgery: adverse effect of elective splenectomy on longterm survival

BACKGROUND

Splenectomy, and in some cases pancreatico splenectomy, has been advocated by surgeons in an effort to improve clearance of metastatic nodes to splenic hilum (node 10) and splenic artery (node 11). Although splenectomy has known effects on increasing morbidity and even mortality after a variety of surgical maneuvers including gastrectomy, the longterm effect on survival is controversial. The purpose of this study is to review and analyze the effect of splenectomy on survival in patients having curative gastrectomy for stomach cancer.

METHODS

We reviewed the role of splenectomy in patients having curative gastrectomy in a data base of stomach cancer patients that had been collected in 1987 as part of an American College of Surgeons Patterns of Care Study. This analysis had involved 18,344 patients, of whom 11,252 were first diagnosed in 1982 as part of a longterm study, and 7,092 were first diagnosed in 1987 as part of a shortterm study. From the two data collection periods information was available on 12,439 patients who received cancer directed abdominal surgery; 21.2% of these patients received a splenectomy. Among the 3,477 patients reported as having a curative gastrectomy (pathologically clear margins), 26.2% received a splenectomy.

RESULTS

The operative mortality was 9.8% with splenectomy and 8.6% without splenectomy. In patients having a curative gastrectomy, the 5-year observed survival rate was 20.9% in patients having splenectomy versus 31% in patients who did not receive splenectomy (p < 0.0001). Examination of differences in survival by stage of diagnosis showed significantly reduced survival outcomes among patients with stage II and III, but not for those diagnosed with stage I or IV disease. The pattern of recurrence was moderately different with a larger proportion of patients having distant metastases among the group of patients who had undergone splenectomy compared with the patients who had not, 29% and 15.5%, respectively. Whether these differences are inherent in the splenectomy or in the associated cofactors was not determined in this study.

CONCLUSIONS

The data suggest elective splenectomy should generally be avoided in patients with stage II and III gastric cancer. In patients with resectable proximal advanced (stage IV) cancer or who have extension to spleen and pancreas or macroscopic nodal metastases to splenic hilum, splenectomy might be necessary to facilitate complete removal of the tumor in an effort to achieve longterm tumor control. The importance of surgical judgment is emphasized as the major deciding factor in determining the need for splenectomy in the individual cancer patient.

Use of Truquant BR radioimmunoassay for early detection of breast cancer recurrence in patients with stage II and stage III disease

PURPOSE

The Truquant BR radioimmunoassay (RIA) (Biomira Diagnostics Inc, Rexdale, Canada) uses the monoclonal antibody B27.29 to quantitate the MUC-1 gene product (CA 27.29 antigen) in serum. We evaluated CA 27.29 antigen in a controlled, prospective clinical trial for its ability to predict relapse in stage II and stage III breast cancer patients.

PATIENTS AND METHODS

Over a 2-year period, 166 patients who had completed therapy for stage II (80.1%) or III (19.9%) breast cancer and were clinically free of disease were serially tested for CA 27.29 antigen levels. The study was double-masked and cancer recurrence was documented based on clinical findings. Patients with two consecutive CA 27.29 antigen test results above the upper limit of normal were considered positive.

RESULTS

The Truquant BR RIA had a sensitivity of 57.7%, specificity of 97.9%, positive predictive value of 83.3%, and negative predictive value of 92.6%. The recurrence rate was 15.7%. A Cox regression analysis showed that the only variable to correlate with recurrent disease was the CA 27.29 antigen test result. Patients with a positive test result had increased odds of having a recurrence (odds ratio, 6.8; P < .00001). The test was effective in predicting recurrence in patients with both distant and locoregional disease. In a subgroup of patients with bone pain, CA 27.29 antigen level was found to identify reliably patients who would subsequently develop recurrent disease.

CONCLUSION

These data demonstrate that the Truquant BR RIA can be used as an aid to predict recurrent breast cancer in patients with stage II and III disease.

Integrating geriatrics and oncology

BACKGROUND

A geriatric education retreat in oncology was held in February 1997 to develop a plan to integrate geriatrics into oncology.

METHODS

A group of 42 geriatricians and medical oncologists convened to assess the means of incorporating the contents of geriatrics into oncology training. The basic science and clinical aspects of the pathogenesis, diagnosis, and treatment of cancers in older persons and the geriatric aspects of aging were presented.

RESULTS AND CONCLUSIONS

This comprehensive review of the problems of aging and cancer provided encouragement to representatives of both disciplines to stimulate further research and clinical training relating to the problems of aging and cancer. The overall conclusions considered means to reach this goal.

Adequacy of chemotherapy prior to cytoreductive surgery in testicular carcinoma

Removal of residual masses after cisplatin-based chemotherapy (cytoreductive surgery) for inoperable or metastatic testicular carcinoma has demonstrated that many partial regressions are defects without malignant cells. Such negative results allow a clarification of complete regression. Failure to achieve complete regression requires intensive salvage chemotherapy or bone marrow transplant. Extended initial chemotherapy could reduce these failures. Cytoreductive surgery was performed on 44 patients with inoperable stage II or stage III testicular cancer with residual defects following chemotherapy. The patients were evaluated according to whether (a) adequate treatment was given based on attaining normal markers followed by two additional courses of therapy, (b) normal markers were achieved but two additional courses were not administered, or (c) normal markers were never attained. These were subdivided into those receiving five or more courses of chemotherapy or fewer than five courses. Patients receiving two additional courses of chemotherapy after markers became normal had a low death rate (15.4%) and highest median follow-up. Fewer patients died if they had five or more courses of chemotherapy (11.8%). Of all those who attained normal markers with at least five or more courses of therapy, 10% are dead. The presence of residual malignant cells in those receiving five or more courses of therapy was 18.2% in contrast to 50% in those receiving fewer courses. Adequate chemotherapy and attainment of normal markers followed by two more courses of therapy results in fewer patients with residual malignant cells, a greater potential of cure, and less need for intensive salvage regimens.

Gastric carcinoma: does lymph node dissection alter survival?

BACKGROUND

Extragastric lymphadenectomy (D2 node dissection) is strongly supported by Japanese data to have survival benefit. Randomized trial data are either inconclusive or nonsupportive of this view. We have reviewed a prospectively gathered database of 18,346 cases of gastric carcinoma from a gastric cancer patient care evaluation study conducted by the American College of Surgeons to assess whether the performance of extragastric node dissection was associated with improved survival in patients who had resection with curative intent (all margins microscopically clear).

STUDY DESIGN

We reviewed a subgroup of patients with curatively resected gastric carcinoma and compared the outcome in patients having extragastric lymph node dissection with the outcome in patients who did not have dissection of N2 nodes.

RESULTS

Among the 3,804 patients having curative resection in the long-term study with more than a five-year follow-up, 695 had dissection of the nodes along the celiac axis, hepatic artery, or splenic artery (N2 nodes); 1,529 patients had removal of the adjacent nodes (N1 nodes) along the gastric tube or the gastric or perigastric nodes (N1 nodes); and 903 patients who had no nodes identified in the resection specimen (essentially N0 nodes removed). For patients having a dissection of N2 nodes, the median survival time was 19.7 months with a five-year survival rate of 26.3 percent; for patients having a dissection of N1 nodes, the median survival time was 24.8 months with a five-year survival rate of 30 percent; among patients having no nodes removed, the median survival time was 29.5 months with a five-year survival rate of 35.6 percent.

CONCLUSIONS

Lymph node dissection (D2) of N2 nodes did not augment survival compared with gastrectomy without node dissection or that included perigastric nodes in the resection. Subgroup analysis of patients with gastric carcinoma having a curative resection did not show benefit of the extragastric node dissection (D2). Continued study is warranted and the data from ongoing clinical trials may yield more conclusive information.

Structural Characterization of Nickel(II) Tetraphenylporphyrin

The structure of 5,10,15,20-tetraphenylporphinatonickel(II) ([Ni( tpp )]) has been studied by both X-ray diffraction (powder and single-crystal methods) and EXAFS. The bond lengths obtained from analysis of the EXAFS agree, within standard deviations, with those obtained from the X-ray diffraction studies. The Ni-N bond length of 1.93(1) Ǻ agrees especially well with the value of 1.931(2) Ǻ obtained from the single-crystal analysis. The powder X-ray diffraction pattern, collected by using synchrotron radiation, is presented.

Optimal number of chemotherapy courses in advanced nonseminomatous testicular carcinoma

BACKGROUND

Nonseminomatous germ cell tumors (NSGCT) (testicular carcinoma) are a curable disease. Stages I and II are nearly 100% curable. Stage III has had remarkable progress in attaining complete regression, but a substantial number fail to be cured. Using platinum-based regimens such as vinblastine, bleomycin, and cisplatin (VBP), or using etoposide instead of vinblastine (BEP), or without bleomycin (EP), four courses of chemotherapy have become a national standard. Based on our prior experience with mithramycin (plicamycin), which used six courses, six courses of VBP chemotherapy were utilized as our treatment goal. This report challenges the concept that "standard therapy" for stage III testicular carcinoma is four courses.

METHOD

From 1976 to 1990, 74 patients with advanced NSGCT were treated with standard doses of plantinum-based chemotherapies. Five or more courses were delivered to 41 patients and fewer than five courses to 33 patients. The intent of therapy was to attain as close to six courses as possible. Because of physician preference, patient adherence, or toxicity, some patients did not reach that goal.

RESULTS

Of 33 patients receiving less than five courses, there were 28 (85%) complete responders, and 26 (78.8%) are alive. Of 41 patients receiving five or more courses, 38 (92.7%) had complete responses, and 34 (83%) are alive. One person in each group is living with nonresectable teratoma present. In the group receiving 5+ courses, two died from causes unrelated to testis cancer and had no testis cancer present. As a result of the initial treatment, there was no evidence of cancer in 24 (72.8%) in the group receiving less than five courses and 35 (85.4%) had no cancer after five or more courses. In considering only patients with advanced level of stage III disease in contrast to minimal or moderate stage III disease, there were fewer complete regressions with less than five courses (64.3%) than with five or more courses (88.0%).

CONCLUSIONS

For minimal stage III disease, four courses of chemotherapy may be adequate. For advanced stage III disease, more chemotherapy provides fewer treatment failures. Once a complete response is achieved without restriction to an arbitrary number of courses, two additional courses may constitute a more curative regimen.

Long-term follow-up of stage III testicular carcinoma treated with mithramycin (plicamycin)

In 1965 we reported mithramycin (plicamycin) to produce objective regression in 7 of 12 patients with advanced testicular carcinoma. Between 1963 and 1975 mithramycin was administered to 62 patients with advanced testicular carcinoma as the initial chemotherapy and to 30 patients who failed to respond to prior chemotherapies. There were 13 complete regressions (23%) in 56 patients who as initial chemotherapy received more than one course of mithramycin. The median follow-up is 23 years with 10 patients still alive. A partial regression occurred in 11 (18%), all of whom are dead. Of 30 patients receiving mithramycin after prior chemotherapies, none had a complete regression, 5 had a partial regression, and all are dead. Of 13 patients undergoing complete regression, 85% never had a recurrence of testicular carcinoma. The median follow-up of 23 years implies that these patients are cured.

Alternating chemotherapy regimens for patients with metastatic breast cancer. A pilot study based on tumor marker kinetics. Cancer and Leukemia Group B

BACKGROUND

Chemotherapy is most effective when applied during the biologically active stage of tumor cells. According to the authors' previous tumor marker kinetic study, methotrexate plus 5-fluorouracil (MF) was found to yield either a cytolytic effect in an MF-sensitive tumor cell population or a cytostatic effect in an MF-resistant population. In the latter, the suppressive effect was transient and the biologic activity resumed in one week after MF administration.

METHODS

Based on this marker kinetic study, an alternating chemotherapy program was designed to study its antitumor and side effects. Methotrexate (M) (200 mg/m2) and 5-fluorouracil (F) (500 mg/m2) were administered intravenously on day 1 followed 24 hours later by leucovorin (L) (10 mg/m2 orally every 6 hours for 6 doses). Cyclophosphamide (C) 300 (mg/m2), doxorubicin (A) (50 mg/m2), and vincristine (V) (1 mg/m2) were given on day 8. The MFL/CAV was given every 4 weeks.

RESULTS

Forty-nine patients with metastatic breast cancer were enrolled; 41 were eligible. There were 5 complete and 23 partial remissions, producing a total response rate of 68%. In 15 patients with liver metastases, the response rate was 73% and the median survival 13.7 months, results superior to those previously reported for this subgroup of patients. Side effects were manageable.

CONCLUSIONS

This regimen, which can be given safely in an outpatient setting, yielded encouraging response and survival rates in patients with visceral-dominant disease with poor prognoses.

Neutron Powder Diffraction Study of Molybdenum and Tungsten Dioxides

Neutron powder diffraction data for MoO2 [P21/c, a 5.6102(3), b 4.8573(2), c 5.6265(3) Ǻ, β 120.915(2)°] and WO2 [P21/c, a 5.5769(2), b 4.8986(1), c 5.6644(2) Ǻ, β 120.678(1)] have been employed to refine structural parameters by the Rietveld method. The results confirm previous studies but have considerably greater precision.

Adjuvant chemotherapy for stage II nonseminomatous germ cell cancer of the testis

BACKGROUND

The success of chemotherapy for Stage III testicular carcinoma warranted its use as an adjuvant therapy for Stage II cancer. The current report reflects the adjuvant program begun at the University of Minnesota using four courses of vinblastine, bleomycin, and cisplatin (VBP) before the onset of the Testicular Cancer Intergroup Study using two courses of chemotherapies.

METHODS

A review of 78 patients with Stage II nonseminomatous germ cell tumors treated between 1972 and 1986 defined three groups: 19 patients treated between 1972 and 1979 with various adjuvant chemotherapies (termed "other"), 37 patients treated from 1975 to 1986 with VBP adjuvant chemotherapy, and 21 patients who received no therapy during the same era of VBP. The latter group was not offered adjuvant chemotherapy at other institutions or declined therapy.

RESULTS

Nineteen patients received adjuvant chemotherapy before the cisplatin era. Their survival rate was 42%, including two patients treated with cisplatin-based chemotherapy for recurrence. In the group of 21 patients who did not receive adjuvant therapy, 14 (66.7%) survived. Of these, five had no recurrence and nine were treated for recurrence. In a third group, adjuvant VBP therapy was given to 37 patients, 32 of whom received four full courses. There have been no recurrences, and 36 (97.3%) remain alive; one obese patient with hypertension died of a ruptured aortic aneurysm 12.9 years after the retroperitoneal lymph node dissection. Nodal involvement was more extensive in the VBP group.

CONCLUSION

Four courses of VBP adjuvant chemotherapy for pathologic Stage II testicular cancer resulted in a 100% cure rate, all patients having been followed up for more than 6 years. Whether two courses are as adequate remains to be determined when long-term follow-up is reported.

Minnesota population cancer risk

BACKGROUND

The Minnesota Cancer Surveillance System (MCSS) provides information on the occurrence of newly diagnosed cancers among Minnesota residents. Cancer is a major cause of death and morbidity in older persons. Population cancer risk (PCR) was assessed as a measure of the number of cancers that will occur in the lifetime of 1000 persons.

METHODS

Approximately 98.6% of all cancers diagnosed in residents of Minnesota are reported by pathologists to the MCSS. By statistical methodology an estimate was made of the total number of cancers that will occur in the lifetime of 1000 people (PCR). The calculation assumes people born today will have the 1988-1990 Minnesota cancer incidence and life expectancy rates.

RESULTS

Incidence rates for all cancers in Minnesota have been increasing. Life expectancy in Minnesota is greater than in most areas of the United States. Approximately 50% of all cancers occurred in Minnesotans older than 70 years. The overall PCR is 459 cancers per 1000 lifetimes. It is estimated that by the year 2020 more than 100,000 living Minnesotans will have had cancer diagnosed during their lifetime.

CONCLUSION

During the next 20 years, as the Baby Boomer generation in Minnesota moves into the high-risk years for cancer, the number of newly diagnosed cancers will increase disproportionately more than the increase in size of the older population. In view of the projected number of patients with cancer by the year 2020, cancer care will be different from what it is today. Geriatric cancer care will become a significant medical, public health, economic, bioethical, and social issue.

Future manpower needs in caring for an older cancer-patient population

The Minnesota Cancer Surveillance System provides data for almost all cancers newly diagnosed in residents of Minnesota. A statistical method, Population Cancer Risk (PCR), estimates the total number of cancers that will occur in the lifetimes of 1,000 people, based on the Minnesota cancer incidence and life expectancy rates from 1988-1990. The overall PCR is 459 cancers per 1,000 lifetimes of persons born today. By year 2020 the Minnesota population will have increased 12% since 1990, but the total cancer incidence will have increased 60%. As a result, there will be an increased demand for medical oncologists, radiotherapists, and surgical subspecialists. Primary care physicians will play an increasing role in cancer prevention, early detection, therapies, and long-term follow-up. Physician's assistants and skilled nurses will add further to patient cancer management. Cancer patients will be older, on average. The future will include changes in the methods of care of the older cancer patients and in economic, social, and bioethical issues involving older persons.