High-gradient millimeter-wave accelerator on a planar dielectric substrate

We report the first high-gradient studies of a millimeter-wave accelerator, employing for the first time a planar dielectric accelerator, powered by means of a 0.5-A, 300-MeV, 11.424-GHz drive electron beam, synchronous at the 8th harmonic, 91.392 GHz. Embedded in a ring-resonator circuit within the electron beam line vacuum, this structure was operated at 20 MeV/m, with a circulating power of 200 kW, for 2 x 10(5) pulses, with no sign of breakdown, dielectric charging, or other deleterious high-gradient phenomena. We also present the first measurement of the quadrupolar content of an accelerating mode.

Toward a definition of HIV expertise: a survey of experienced HIV physicians

Medical care for human immunodeficiency virus (HIV)-infected persons has grown increasingly complex, yet few studies have examined experienced HIV physicians' views about current HIV medical care. The objective of this study was to examine the relationship between physicians' HIV experience, self-perceived expertise, and confidence with providing 18 aspects of HIV medical care and between confidence in aspects of care and medical specialty. At geographically diverse, HIV continuing medical education programs conducted in the fall of 1999, 359 currently practicing HIV physicians completed a written survey measuring participants' demographic characteristics, experience, HIV expertise, and level of confidence providing essential aspects of HIV care. Participants currently managed a median of 50 HIV-infected patients with a career total of 300. Significant correlations were found between experience and expertise items and experience and 15 of 18 confidence items. Confidence levels varied from 11% to 85% highly confident across 18 aspects of HIV care. Physicians' confidence with providing aspects of HIV care varied by the three predominant specialty groups (infectious diseases, internal medicine, and family practice/general medicine). Physicians who have informally specialized in HIV care reported a range of self-perceived expertise and confidence, indicating the complexity of HIV medical care today. Our results suggest that even the most experienced HIV physicians in the United States continue to benefit from more experience and that each medical specialty examined in this study brings its own set of skills needed to provide optimal HIV care. This study constitutes a first step toward defining and formalizing HIV medical care.

Knowledgeable, consistent, competent care: meeting the challenges of delivering quality cancer care in remote northern communities

The Northwestern Ontario Regional Cancer Centre (NWORCC) has created outreach services that provide chemotherapy and supportive care to clients in thirteen small, remote communities. Located 100-600 km from the NWORCC, these satellite oncology services are staffed by local physicians, specially prepared nurses and support staff. The present paper reports selected findings from an evaluation of the service, based on two rounds of site visits, interviews and surveys of providers and clients. Although the consensus was that quality care was being delivered, local hospitals and other organizations had to address a variety of challenges. Those discussed in the paper include: maintaining provider competency, strengthening supportive care networks, and adjusting staffing and other resources to meet increased demands for care.

Oculopharyngeal muscular dystrophy: phenotypic and genotypic studies in a UK population

Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant disorder of late onset that commonly presents with ptosis and dysphagia. The genetic basis of the condition has been identified recently as a stable trinucleotide repeat expansion in exon 1 of the poly(A) binding protein 2 gene (PABP2), in which (GCG)(6) is the normal repeat length. The prevalence of OPMD is greatest in patients of French-Canadian origin. It is not clear if expansion repeat length is a reliable test in other populations. In this study, we analysed the phenotypic and genotypic characteristics of 31 patients with OPMD in the UK. Ptosis was the first reported symptom in two-thirds of the patients, and half of the subjects studied had evidence of ophthalmoplegia. All but one family had a pathological expansion in the PABP2 gene, ranging from (GCG)(8) to (GCG)(13). In contrast to the French-Canadian population, (GCG)(10) was almost as common as (GCG)(9), evidence against a strong founder effect in the UK population. There was a weak association between repeat length and age of disease onset. Patients with longer repeat lengths, such as (GCG)(13), developed severe limb weakness early in the disease. We were unable to detect the (GCG)(7) polymorphism in over 200 normal controls, suggesting that the frequency of this expansion is lower than that found in the French-Canadian population. One family was negative for the expansion. Affected members presented with the classical features of OPMD, namely ptosis, dysphagia and cytoplasmic inclusions on muscle biopsy, although with some atypical features, such as early age of onset, high serum levels of creatine kinase and a profound ophthalmoplegia. This family is an example of a GCG expansion-negative oculopharyngeal syndrome requiring further genetic investigation. We conclude that PABP2 analysis is a reliable non-invasive diagnostic test for OPMD in the UK population.

Solitary pancreatic metastasis from a primary colonic tumor detected by PET scan: report of a case

PURPOSE

A case of a solitary pancreatic metastasis from a primary colonic carcinoma is reported.

METHODS

The history and use of carcinoembryonic antigen, computed tomography, and positron emission tomography in this case and the follow-up of colorectal cancer are reviewed.

RESULTS

Recurrent disease was suspected by an increasing carcinoembryonic antigen level. However, conventional imaging with computed tomography on more than one occasion failed to identify any recurrence. The pancreatic metastasis was accurately localized by positron emission tomography scanning and confirmed on subsequent laparotomy. A histologically complete resection was performed and the patient remained in remission with a normal carcinoembryonic antigen 12 months postoperatively.

CONCLUSION

This case reports an unusual site of solitary metastasis in colorectal cancer and supports the further investigation of positron emission tomography in follow-up of colorectal cancer.

Elimination of glucagon-like peptide 1R signaling does not modify weight gain and islet adaptation in mice with combined disruption of leptin and GLP-1 action

Leptin and glucagon-like peptide 1 (GLP-1) exhibit opposing actions in the endocrine pancreas. GLP-1 stimulates insulin biosynthesis, secretion, and islet growth, whereas leptin inhibits glucose-dependent insulin secretion and insulin gene transcription. In contrast, GLP-1 and leptin actions overlap in the central nervous system, where leptin has been shown to activate GLP-1 circuits that inhibit food intake. To determine the physiological importance of GLP-1 receptor (GLP-1R)-leptin interactions, we studied islet function and feeding behavior in ob/ob:GLP-1R(-/-) mice. Although GLP-1R actions are thought to be essential for glucose-dependent insulin secretion, the levels of fasting glucose, glycemic excursion after glucose loading, glucose-stimulated insulin, and pancreatic insulin RNA content were similar in ob/ob:GLP-1R(+/+) versus ob/ob:GLP-1R(-/-) mice. Despite evidence linking GLP-1R signaling to the regulation of islet neogenesis and proliferation, ob/ob:GLP-1R(-/-) mice exhibited significantly increased islet numbers and area and an increase in the number of large islets compared with GLP-1R(+/+) or (-/-) mice (P < -0.01 to 0.05). Similarly, growth rates and both shortand long-term control of food intake were comparable in ob/ob:GLP-1R(+/+) versus ob/ob:GLP-1R4(-/-) mice. Furthermore, leptin produced a similar inhibition of food intake in GLP-1R(-/-), ob/ob:GLP-1R(+/+), and ob/ob:GLP1R4(-/-) mice. These findings illustrate that although leptin and GLP-1 actions overlap in the brain and endocrine pancreas, disruption of GLP-1 signaling does not modify the response to leptin or the phenotype of leptin deficiency in the ob/ob mouse, as assessed by long-term control of body weight or the adaptive beta-cell response to insulin resistance in vivo.

GM-CSF with biochemotherapy (cisplatin, DTIC, tamoxifen, IL-2 and interferon-alpha): a phase I trial in melanoma

BACKGROUND

Ineffective tumour antigen processing is recognised as an important cause of failure of immunotherapy in melanoma. GM-CSF may augment the cytotoxic lymphocyte response by activating antigen-presenting cells. This study evaluates a schedule combining GM-CSF with biochemotherapy.

PATIENTS AND METHODS

Nineteen patients with advanced malignant melanoma received cisplatin (25 mg/m2 days 1-3). dacarbazine (220 mg/m2 days 1-3), interleukin-2 (9 MIU/m2/24 h) and interferon-alpha2b (5 MIU/m2) both days 6-10 and days 17-21, and tamoxifen 40 mg/day continuously. Subcutaneous GM-CSF was given in escalating doses to three cohorts: 1) 450 microg/m2 days 4-5 and 15-16; 2) as 1) plus 225 microg/m2 days 6-10 and 17-21; 3) 450 microg/m2 days 4-10 and 15-21. Each cycle was 28 days.

RESULTS

Constitutional side effects were the major non-haematological toxicity and lymphopaenia the main haematological toxicity. Six patients responded (32%, 95% confidence interval: 13%-57%), two patients had complete remission. There was an apparent trend for increasing responses with increasing GM-CSF dose; zero of six responses in cohort 1, two of seven in cohort 2 and three of six in cohort 3 (P = 0.016). Median overall survival was 6.2 months. Increasing GM-CSF doses significantly increased serum concentrations of neopterin and TNF-alpha.

CONCLUSIONS

The combination of GM-CSF with biochemotherapy is feasible and there appears to be a dose-response relationship with GM-CSF in terms of host immunological response, and possibly clinical efficacy.

Age reporting among white Americans aged 85+: results of a record linkage study

This study investigates age reporting on the death certificates of older white Americans. We link a sample of death certificates for native-born whites aged 85+ in 1985 to Social Security Administration records and to records of the U.S. censuses of 1900, 1910, and 1920. When ages in these sources are compared, inconsistencies are found to be minimal, even beyond age 95. Results show little distortion and no systematic biases in the reported age distribution of deaths. To explore the effect of age misreporting on old-age mortality, we estimate "corrected" age-specific death rates by the extinct-generation method for the U.S. white cohort born in 1885. With few exceptions, corrected and uncorrected rates in single years differ by less than 3% and are not systematically biased. When we compare corrected rates with those for the same birth cohort in France, Japan, and Sweden, we find that white American mortality at older ages is exceptionally low.

Combining platinum, paclitaxel and anthracycline in patients with advanced gynaecological malignancy

Two meta-analyses have suggested that the addition of an anthracycline to platinum-based chemotherapy may improve survival in advanced ovarian cancer, and two randomised trials have demonstrated superiority of paclitaxel over cyclophosphamide in platinum combinations. A combination of platinum, anthracycline and paclitaxel would, therefore, be a reasonable experimental arm of any future randomised trial in patients with epithelial ovarian carcinoma (EOC). Patients who required chemotherapy for EOC but were ineligible for standard trials or had other gynaecological tumours that required similar platinum-based chemotherapy were considered for this pilot. The platinum/anthracycline/paclitaxel regimen (G-CAT) was given 3-weekly and consisted of doxorubicin 50 mg/m(2) or epirubicin 60 mg/m(2) intravenously (i.v.) bolus, paclitaxel 175 mg/m(2) (i.v.) over 3 h and either cisplatin 75 mg/m(2) (i.v.) or carboplatin AUC 6, with granulocyte colony-stimulating factor (G-CSF) at the neutrophil nadir. Different combinations were used in order to determine the least toxic regimen. Toxicity and response were assessed according to CTC and WHO criteria, respectively. 26 patients entered the study, 13 with EOC and 13 with other gynaecological cancers (peritoneal, fallopian tube, mixed Mullerian). Median age was 49 years (range: 27-67). 8 patients received carboplatin/doxorubicin/paclitaxel, 8 cisplatin/doxorubicin/paclitaxel and 10 carboplatin/epirubicin/paclitaxel. A total of 135 cycles of chemotherapy were delivered, with a median of 6 cycles per patient (range: 2-6). 54 (40%) cycles required G-CSF support and 17 (65%) patients required at least one dose reduction. All patients experienced grade 4 neutropenia and 13 (50%) patients developed grade 3-4 thrombocytopenia (12 of whom had received carboplatin). There were 4 (15%) patients with grade 3/4 infections but no septic deaths. Non-haematological toxicities were manageable, lethargy occurred in 75% of cisplatin-treated patients. Grade 1/2 cardiotoxicity, as assessed pre- and post-treatment by left ventricular ejection fraction, was observed in 6/13 (46%) patients who had received doxorubicin and 2/7 (29%) epirubicin-treated patients. No clinically detectable cardiac toxicity was encountered. The response rate in 25 evaluable patients was 76% (12 CR, 7 PR). Dose intensity was highest in the carboplatin/epirubicin/paclitaxel combination. G-CAT shows high activity and can be administered safely, but only very fit patients are suitable for this regimen as it is associated with considerable toxicity. Carboplatin/epirubicin/paclitaxel was the best tolerated regimen overall.

Are 18fluorodeoxyglucose positron emission tomography and magnetic resonance imaging useful in the prediction of relapse in lymphoma residual masses?

Treatment of both Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) frequently results in a residual mass visible radiologically. Such patients may receive radiotherapy unnecessarily because the residual mass may represent benign fibrotic tissue rather than residual active lymphoma. Radiotherapy has been shown to have significant short and more worrying long-term toxicity. Refining the criteria for its use would be a major advance. A number of clinical investigations have been evaluated to more accurately determine the nature of such lesions, including erythrocyte sedimentation rate (ESR), magnetic resonance imaging (MRI) and high-dose gallium-67 scanning (HDGS) but none has proven utility. 18[F]-fluorodeoxyglucose positron emission tomography (FDG-PET) is an imaging technique that has been shown to be useful in distinguishing fibrosis from residual active disease in solid tumours. The aim of this study was to compare FDG PET and MRI in the assessment of residual masses following treatment for lymphoma. Patients with NHL/HD who had a residual mass following chemotherapy were eligible for this study. Patients had a combination of MRI and/or PET. All scans were completed within 5 months of the end of treatment. Patients were followed-up for relapse. 56 patients had an MRI scan, 24 had a PET scan and 22 patients had both investigations. Overall sensitivity and specificity, respectively, were for MRI 45% and 74%, PET 50% and 69%, and PET/MRI concurring 50% and 67%. There was a trend for improved relapse-free survival (RFS) with a negative result of both MRI and PET, but this was not statistically significant. The predictive value for both tests failed to reach statistical significance. Subgroup analysis suggests that PET may be better at predicting relapse in patients with NHL, especially those with masses above the diaphragm. There is no convincing evidence that either MRI or PET or the combination can reliably predict relapse within residual masses after treatment for lymphoma. A negative PET scan however appears to be more informative than a positive result and may well aid clinical decision making. There are a number of factors that may produce false-positive results, including post-treatment inflammatory changes, the sensitivity of the test in the setting of minimal residual disease and the heterogeneity of the histological subtypes studied. A negative PET (or MRI) result in lymphoma residual masses following therapy may negate the necessity for further therapy such as chemotherapy or radiotherapy and their concomitant toxicities.

Multivariate survivorship analysis using two cross-sectional samples

As an alternative to survival analysis with longitudinal data, I introduce a method that can be applied when one observes the same cohort in two cross-sectional samples collected at different points in time. The method allows for the estimation of log-probability survivorship models that estimate the influence of multiple time-invariant factors on survival over a time interval separating two samples. This approach can be used whenever the survival process can be adequately conceptualized as an irreversible single-decrement process (e.g., mortality, the transition to first marriage among a cohort of never-married individuals). Using data from the Integrated Public Use Microdata Series (Ruggles and Sobek 1997), I illustrate the multivariate method through an investigation of the effects of race, parity, and educational attainment on the survival of older women in the United States.

Biologic properties and therapeutic potential of glucagon-like peptide-2

BACKGROUND

Glucagon-like peptide-2 (GLP-2), a 33 amino acid, proglucagon-derived peptide with intestinotrophic activity, is secreted from enteroendocrine cells in the small and large intestine.

METHODS

This review describes recent advances in our understanding of GLP-2 physiology from rodent experiments in vivo.

RESULTS

GLP-2 administration induces mucosal epithelial proliferation in small and large bowel and stomach. GLP-2 is rapidly degraded by the enzyme dipeptidyl peptidase IV (DPP-IV) to produce the biologically inactive form GLP-2(3-33), however, GLP-2 analogs that confer resistance to DPP-IV exhibit enhanced biologic activity in vivo. GLP-2-treated bowel retains normal to enhanced functional absorptive capacity. Furthermore, GLP-2 infusion prevents total parenteral nutrition (TPN)-associated intestinal hypoplasia, and enhances bowel adaptation and nutrient absorption in rats following small bowel resection. GLP-2 also reverses weight loss and improves histologic and biochemical parameters of disease activity in mice with experimental colitis.

CONCLUSIONS

GLP-2 is an intestine-derived peptide with intestinotrophic properties that may be therapeutically useful in diseases characterized by intestinal damage or insufficiency.

Essential requirement for Pax6 in control of enteroendocrine proglucagon gene transcription

The primary function of islet A cells is the synthesis and secretion of glucagon, an essential hormonal regulator of glucose homeostasis. The proglucagon gene is also expressed in enteroendocrine L cells of the intestinal epithelium, which produce glucagon-like peptide 1 (GLP-1) and glucagon-like peptide 2 (GLP-2), regulators of insulin secretion and intestinal growth, respectively. We show here that Pax6, a critical determinant of islet cell development and proglucagon gene expression in islet A cells, is also essential for glucagon gene transcription in the small and large intestine. Pax6 is expressed in enteroendocrine cells, binds to the G1 and G3 elements in the proglucagon promoter, and activates proglucagon gene transcription. The dominant negative Pax6 allele, SEYNeu, represses proglucagon gene transcription in enteroendocrine cells. Mice homozygous for the SEYNeu mutation exhibit markedly reduced levels of proglucagon mRNA transcripts in the small and large intestine, and GLP-1 or GLP-2-immunopositive enteroendocrine cells were not detected in the intestinal mucosa. These findings implicate an essential role for Pax6 in the development and function of glucagon-producing cells in both pancreatic and intestinal endodermal lineages.

Surgery plus chemotherapy or chemotherapy alone for primary intermediate- and high-grade gastric non-Hodgkin's lymphoma: the Royal Marsden Hospital experience

Primary gastric lymphomas (PGL) have traditionally been treated with surgery followed by chemotherapy or radiotherapy. Surgery was thought to improve staging, optimise local disease control and reduce risk of perforation or bleeding, but recent studies question its role. In this study, patients with intermediate- or high-grade PGL who received chemotherapy from 1985 to 1996 at the Royal Marsden Hospital were identified using a prospectively accrued database. A total of 37 patients (6 with low-grade mucosa-associated lymphoid tissue lymphoma (MALT-L), 9 with high-grade MALT-L, 20 with diffuse large B-cell (DLBC) lymphoma and 2 other histologies), 17 of whom had localised disease, were treated with either surgery plus chemotherapy or chemotherapy alone. 5-year overall survival for localised and advanced PGL was 94 and 50%, respectively, with no differences between the two treatments over a 53 months median follow-up. No perforations or serious bleeding occurred. Surgery is associated with important morbidity and we detected no benefit of surgery prior to chemotherapy in this limited series of patients.

Potent immunostimulatory dendritic cells can be cultured in bulk from progenitors in normal infant and adult myasthenic human thymus

Low density cells can readily be enriched from thymus tissue both of children undergoing cardiac surgery and of older patients with myasthenia gravis, and can be cryostored in bulk. When fresh or thawed cells are cultured with granulocyte-macrophage colony-stimulating factor and stem cell factor with or without tumour necrosis factor-alpha (TNF-alpha), they generate numerous cells with the characteristic ultrastructural, phenotypic and functional properties of dendritic cells. These proved to be very potent, both as stimulators of primary mixed leucocyte responses and as costimulators in oxidative mitogenesis. Especially after exposure to TNF-alpha, these dendritic cells also processed a natural epitope from a 437-residue polypeptide and presented it efficiently to an autoimmune T-cell clone (of T helper type 0 phenotype). Thus, immunostimulatory dendritic cells can be cultured in relative abundance from progenitors in infant and adult human thymus. Both are convenient sources of potent antigen-presenting cells of identifiable origins, e.g. for use in selecting human T-cell lines.

Childhood conditions that predict survival to advanced ages among African-Americans

This paper investigates the social and economic circumstances of childhood that predict the probability of survival to age 85 among African-Americans. It uses a unique study design in which survivors are linked to their records in U.S. Censuses of 1900 and 1910. A control group of age and race-matched children is drawn from Public Use Samples for these censuses. It concludes that the factors most predictive of survival are farm background, having literate parents, and living in a two-parent household. Results support the interpretation that death risks are positively correlated over the life cycle.

A human cDNA sequence with homology to non-mammalian lysophosphatidic acid acyltransferases

A novel human homologue of Escherichia coli, yeast and plant 1-acylglycerol-3-phosphate acyltransferase has been isolated from U937 cell cDNA. Expression of the cloned sequence in 1-acylglycerol-3-phosphate acyltransferase-deficient E. coli resulted in increased incorporation of oleic acid into cellular phospholipids. Membranes made from COS7 cells transfected with the cDNA exhibited higher acyltransferase activity towards a range of donor fatty acyl-CoAs and lysophosphatidic acid. Northern-blot analysis of the cDNA sequence indicated high levels of expression in immune cells and epithelium. Rapid amplification of cDNA ends revealed differentially expressed splice variants, which suggests regulation of the enzyme by alternative splicing. This cDNA therefore represents the first described sequence of a mammalian gene homologous to non-mammalian lysophosphatidic acid acyltransferases.

Cisplatin and 5-fluorouracil for symptom control in advanced salivary adenoid cystic carcinoma

Adenoid cystic carcinoma is a relatively rare tumour which arises in the parotid and submandibular salivary glands. Initial management is surgical, often with post-operative radiotherapy, but local relapse is common and distant metastasis not infrequent. Chemotherapy is generally reserved for cases where symptoms are not controlled by other means, since the tumour is slow growing and the response rate frequently disappointing. Cisplatin and 5-fluorouracil (5-FU) both show single agent activity in this disease but had not been previously investigated in combination. All patients referred for palliative chemotherapy of metastatic, symptomatic, histologically confirmed adenoid cystic carcinoma between November 1990 and February 1994 were considered for this study. The drugs were administered as follows: cisplatin 100 mg/m2 with appropriate pre- and post-hydration and 5-FU on a 4-day schedule of 1 g/m2/day. A total of 11 patients (7 male, 4 female) with median age 53 years (range 34-69) received 46 courses of chemotherapy (median four, range one to six). All patients had prior surgery and 8 had previously received radiotherapy. There were no objective responses of > 50% reduction in tumour size. 3 patients had a minor response and two progressed on treatment. The symptomatic response rate, however, was 64%, which compares favourably with other previously reported regimens. Toxicity was manageable. The median time to tumour progression was 9 months (range 0-38) and median survival was 12 months (range 1-65). This cisplatin/5-FU regimen would appear to produce a low rate of objective response but useful palliative benefits in advanced symptomatic adenoid cystic carcinoma. Prior series suggest that a higher objective response rate may be possible with a platinum/anthracycline/fluorouracil combination, and investigation of such a regimen is warranted.

Chemotherapy for symptom control in recurrent squamous cell carcinoma of the head and neck

BACKGROUND

The role of chemotherapy in patients with recurrent squamous cell carcinomas of the head and neck (SCCHN) is unclear. The aim of this study was to assess the ability of combination chemotherapy to control symptoms in this setting.

PATIENTS AND METHODS

Using a prospectively accrued database all patients referred for chemotherapy with symptomatic relapse following surgery were identified. Objective response was recorded using standard criteria and maximum symptom response was assessed retrospectively from case notes using a published scoring scale.

RESULTS

A total of 57 (median age 56, range 37-85) patients were studied who had received mainly cisplatin/5-fluorouracil combinations. Thirty-seven had previously received radiotherapy. Fifty-two patients had evaluable disease; 18 (35%) had objective responses (14 PRs and 4 CRs). There were a total of 103 symptoms recorded with eight different individual symptoms. Forty-four (43%) symptoms improved on treatment, 52 (50%) were unchanged and 7 (7%) worsened. The number of patients with improvement in the most frequently recorded symptoms were as follows: pain 11/28 (39%), swelling 12/23 (52%) and dysphagia 6/18 (33%). Sixty-seven percent of patients with objective response also had an improvement in their symptoms but a significant proportion (33%) of non-responders had a symptomatic response. Lack of objective response was not correlated with worsening symptoms. Grade 3/4 toxicity was uncommon (6%-17%) and there were no toxic deaths. A majority of patients (82%) experienced either no change or an improvement in performance status.

CONCLUSION

These results demonstrate that chemotherapy improves many of the symptoms associated with recurrent SCCHN, without deterioration in performance status. Symptomatic improvement is more likely if there is evidence of significant tumour shrinkage, but even non-responding patients can benefit.