Sonographers' self-reported visualization of normal postmenopausal ovaries on transvaginal ultrasound is not reliable: results of expert review of archived images from UKCTOCS

OBJECTIVE

In the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS), self-reported visualization rate (VR) of the ovaries by the sonographer on annual transvaginal sonographic (TVS) examinations was a key quality control (QC) metric. The objective of this study was to assess self-reported VR using expert review of a random sample of archived images of TVS examinations from UKCTOCS, and then to develop software for measuring VR automatically.

METHODS

A single expert reviewed images archived from 1000 TVS examinations selected randomly from 68 931 TVS scans performed in UKCTOCS between 2008 and 2011 with ovaries reported as 'seen and normal'. Software was developed to identify the exact images used by the sonographer to measure the ovaries. This was achieved by measuring caliper dimensions in the image and matching them to those recorded by the sonographer. A logistic regression classifier to determine visualization was trained and validated using ovarian dimensions and visualization data reported by the expert.

RESULTS

The expert reviewer confirmed visualization of both ovaries (VR-Both) in 50.2% (502/1000) of the examinations. The software identified the measurement image in 534 exams, which were split 2:1:1 providing training, validation and test data. Classifier mean accuracy on validation data was 70.9% (95% CI, 70.0-71.8%). Analysis of test data (133 exams) provided a sensitivity of 90.5% (95% CI, 80.9-95.8%) and specificity of 47.5% (95% CI, 34.5-60.8%) in detecting expert confirmed visualization of both ovaries.

CONCLUSIONS

Our results suggest that, in a significant proportion of TVS annual screens, the sonographers may have mistaken other structures for normal ovaries. It is uncertain whether or not this affected the sensitivity and stage at detection of ovarian cancer in the ultrasound arm of UKCTOCS, but we conclude that QC metrics based on self-reported visualization of normal ovaries are unreliable. The classifier shows some potential for addressing this problem, though further research is needed. © 2017 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

New tumor markers: CA125 and beyond

A variety of biomarkers have been developed to monitor growth of ovarian cancer and to detect disease at an early interval. CA125 (MUC16) has provided a useful serum tumor marker for monitoring response to chemotherapy, detecting disease recurrence, distinguishing malignant from benign pelvic masses, and potentially improving clinical trial design. A rapid fall in CA125 during chemotherapy predicts a favorable prognosis and could be used to redistribute patients on multiarmed randomized clinical trials. Several studies now document that CA125 can serve as a surrogate marker for response in phase II trials. Serial measurement of CA125 might also provide a useful marker for monitoring stabilization of disease with cytostatic targeted therapeutic agents. The greatest potential for serum markers may be in detecting ovarian cancer at an early stage. A rising CA125 can be used to trigger transvaginal sonography (TVS) in a small fraction of patients. An algorithm has been developed that calculates risk of ovarian cancer based on serial CA125 values and refers patients at highest risk for TVS. Use of the algorithm is currently being evaluated in a trial with 200,000 women in the UK that will test critically the ability of a two-stage screening strategy to improve survival in ovarian cancer. Whatever the outcome, as 20% of ovarian cancers have little or no expression of CA125, additional serum markers will be required to detect all patients in an initial phase of screening. More than 30 serum markers have been evaluated alone and in combination with CA125 by different investigators. Some of the most promising include: HE4, mesothelin, M-CSF, osteopontin, kallikrein(s), and soluble EGF receptor. Two proteomic approaches have been used: one examines the pattern of peaks on mass spectroscopy and the other uses proteomic analysis to identify a limited number of critical markers that can be assayed by more conventional methods. Both approaches are promising and require further development. Several groups are placing markers on multiplex platforms to permit simultaneous assay of multiple markers with very small volumes of serum. Mathematical techniques are being developed to analyze combinations of marker levels to improve sensitivity and specificity. In the future, serum markers should improve the sensitivity of detecting recurrent disease as well as facilitate earlier detection of ovarian cancer.

New tumor markers: CA125 and beyond

A variety of biomarkers have been developed to monitor growth of ovarian cancer and to detect disease at an early interval. CA125 (MUC16) has provided a useful serum tumor marker for monitoring response to chemotherapy, detecting disease recurrence, distinguishing malignant from benign pelvic masses, and potentially improving clinical trial design. A rapid fall in CA125 during chemotherapy predicts a favorable prognosis and could be used to redistribute patients on multiarmed randomized clinical trials. Several studies now document that CA125 can serve as a surrogate marker for response in phase II trials. Serial measurement of CA125 might also provide a useful marker for monitoring stabilization of disease with cytostatic targeted therapeutic agents. The greatest potential for serum markers may be in detecting ovarian cancer at an early stage. A rising CA125 can be used to trigger transvaginal sonography (TVS) in a small fraction of patients. An algorithm has been developed that calculates risk of ovarian cancer based on serial CA125 values and refers patients at highest risk for TVS. Use of the algorithm is currently being evaluated in a trial with 200,000 women in the UK that will test critically the ability of a two-stage screening strategy to improve survival in ovarian cancer. Whatever the outcome, as 20% of ovarian cancers have little or no expression of CA125, additional serum markers will be required to detect all patients in an initial phase of screening. More than 30 serum markers have been evaluated alone and in combination with CA125 by different investigators. Some of the most promising include: HE4, mesothelin, M-CSF, osteopontin, kallikrein(s), and soluble EGF receptor. Two proteomic approaches have been used: one examines the pattern of peaks on mass spectroscopy and the other uses proteomic analysis to identify a limited number of critical markers that can be assayed by more conventional methods. Both approaches are promising and require further development. Several groups are placing markers on multiplex platforms to permit simultaneous assay of multiple markers with very small volumes of serum. Mathematical techniques are being developed to analyze combinations of marker levels to improve sensitivity and specificity. In the future, serum markers should improve the sensitivity of detecting recurrent disease as well as facilitate earlier detection of ovarian cancer.

Longitudinal CA125 detection of sporadic papillary serous carcinoma of the peritoneum

In this case, rising longitudinal levels of CA125 were significant in the detection of peritoneal papillary serous carcinoma, and led to the indication for surgery. Rising longitudinal CA125 has been shown to be important in the detection of ovarian cancer, but little data exist as to its relevance for the detection of peritoneal papillary serous carcinoma. This rare primary tumor is usually associated with women at high risk for epithelial ovarian carcinoma, although this patient was not at high risk as she had no familial breast or ovarian cancer history.

Longitudinal CA125 detection of sporadic papillary serous carcinoma of the peritoneum

In this case, rising longitudinal levels of CA125 were significant in the detection of peritoneal papillary serous carcinoma, and led to the indication for surgery. Rising longitudinal CA125 has been shown to be important in the detection of ovarian cancer, but little data exist as to its relevance for the detection of peritoneal papillary serous carcinoma. This rare primary tumor is usually associated with women at high risk for epithelial ovarian carcinoma, although this patient was not at high risk as she had no familial breast or ovarian cancer history.

Prostasin, a potential serum marker for ovarian cancer: identification through microarray technology

BACKGROUND

Screening biomarkers for ovarian cancer are needed because of its late stage at diagnosis and poor survival. We used microarray technology to identify overexpressed genes for secretory proteins as potential serum biomarkers and selected prostasin, a serine protease normally secreted by the prostate gland, for further study.

METHODS

RNA was isolated and pooled from three ovarian cancer cell lines and from three normal human ovarian surface epithelial (HOSE) cell lines. Complementary DNA generated from these pools was hybridized to a microarray slide, and genes overexpressed in the cancer cells were identified. Real-time quantitative polymerase chain reaction was used to examine prostasin gene expression in ovarian cancer and HOSE cell lines. Anti-prostasin antibodies were used to examine prostasin expression and to measure serum prostasin by an enzyme-linked immunosorbent assay in 64 case patients with ovarian cancer and in 137 control subjects. Previously determined levels of CA 125, an ovarian cancer marker, were available from about 70% of all subjects. All statistical tests were two-sided.

RESULTS

Prostasin was detected by immunostaining more strongly in cancerous ovarian epithelial cells and stroma than in normal ovarian tissue. The mean level of serum prostasin was 13.7 microg/mL (95% confidence interval [CI] = 10.5 to 16.9 microg/mL) in 64 case patients with ovarian cancer and 7.5 microg/mL (95% CI = 6.6 to 8.3 microg/mL) in 137 control subjects (P<.001, after adjustment for the subject's age, year of collection, and specimen quality). In 14 of 16 case patients with both preoperative and postoperative serum samples, postoperative prostasin levels were statistically significantly lower than preoperative levels (P =.004). In 37 case patients with nonmucinous ovarian cancer and in 100 control subjects for whom levels of CA 125 and prostasin were available, the combination of markers gave a sensitivity of 92% (95% CI = 78.1% to 98.3%) and a specificity of 94% (95% CI = 87.4% to 97.7%) for detecting ovarian cancer.

CONCLUSIONS

Prostasin is overexpressed in epithelial ovarian cancer and should be investigated further as a screening or tumor marker, alone and in combination with CA 125.

Survival analysis in familial ovarian cancer, a case control study

OBJECTIVE

familial ovarian cancer patients have been found to differ from sporadic cases, clinically as well as in the molecular make-up of the tumour. Here, a case control study is performed to analyse potential differences in survival.

STUDY DESIGN

31 families with a strong history of ovarian and/or breast cancer presenting to a family cancer clinic 44 ovarian cancer patients were included. Each patient was matched for age and stage with controls from a cancer registry. Survival rates and the effect of several prognostic factors were analysed.

RESULTS

median survival in the study group differed significantly from controls. A survival benefit for familial cases was maintained up to 5 years after diagnosis. Long-term survival was equally poor in both groups.

CONCLUSION

the difference in survival between familial ovarian cancer cases and matched controls may reflect differences in biological behaviour. This may have important implications for the management and prevention of familial ovarian cancer.

Increased mortality in postmenopausal women with serum CA125 elevation

OBJECTIVES

Serum CA125 is used in monitoring treatment and detecting recurrence in ovarian cancer (OC). We have also shown that CA125 can be used with ultrasound for the early detection of OC. However, physiological, benign, and malignant conditions are also associated with CA125 elevation. The aim of the study was to determine the prognostic implications of CA125 elevation in asymptomatic postmenopausal women.

METHODS

The study involved 771 volunteers in an OC screening trial of 22,000 women who had elevated serum CA125 levels (>/=30 U/ml). The control group consisted of an equal number of volunteers with normal levels. Survival was analyzed from the first point of CA125 elevation. Univariate analyses utilized the log-rank chi2 test. A logistic model was constructed for the multivariate analyses.

RESULTS

The mean duration of follow-up was 1614 days (SD 897 days). Eighty-four women died (elevated CA125 group-62, control group-22). Univariate analyses showed that mortality in the elevated CA125 group was significantly greater (log-rank chi2 = 23.556, P < 0.0001, RR = 2.76), even when preexisting morbid conditions were excluded (log-rank chi2 = 14.644, P = 0.0001, RR = 2.4). Multivariate analysis showed that CA125 elevation, age (>60 years), and a prior history of cancer were associated with a poor prognosis.

CONCLUSIONS

Serum CA125 elevation is associated with a significantly increased risk of death from all causes in the next 5 years. These findings may have implications for asymptomatic postmenopausal women with CA125 elevation.

Serum CA125 elevation and risk of clinical detection of cancer in asymptomatic postmenopausal women

BACKGROUND

This study was undertaken to assess the correlation between CA125 elevation, a past history of cancer, and future risk of a diagnosis of cancer among asymptomatic postmenopausal women.

METHODS

The subjects consisted of a study group of 771 women with elevated CA125 (> or =30 U/mL) and a control group of 771 women with CA125 <30 U/mL. They were selected from a prospective ovarian carcinoma screening trial of 22,000 postmenopausal women followed for a mean of 2269 days.

RESULTS

Subjects in the study group were more likely to have a past history of cancer than subjects in the control group (odds ratio [OR] 2.31, 95% confidence interval [CI] 1.49-3.58). Much of the difference in cancer risk prior to CA125 testing was attributable to a past history of breast carcinoma (OR 2.53, 95% CI 1.45-4.42), but CA125 elevation did not predict recurrence of breast carcinoma. Subjects in the study group were also more likely to develop cancer in the future (OR 2.53, 95% CI 1.61-3.97). This difference was due to an increased risk of gynecologic cancer (OR 30.09, 95% CI 4.09-221.59). CA125 elevation was not associated with an increase in the future risk of developing breast carcinoma (OR 1.19, 95% CI 0.53-2.66) or nongynecologic cancer (OR 1.43, 95% CI 0.86-2.36).

CONCLUSIONS

Elevated CA125 in asymptomatic postmenopausal women is not a predictor of nongynecologic cancer or recurrence of cancer, and further investigation should be limited to the detection of gynecologic cancers.

Risk of diagnosis of ovarian cancer after raised serum CA 125 concentration: a prospective cohort study

OBJECTIVE

To determine the risk of invasive epithelial ovarian cancer and fallopian tube cancer associated with a raised concentration of the tumour marker CA 125 in asymptomatic postmenopausal women.

DESIGN

Serum CA 125 concentration was measured annually in study participants for one to four years. Participants with a concentration > or = 30 U/ml were recalled for abdominal ultrasonography. Follow up was by annual postal questionnaire.

SETTING

General practice, occupational health departments, ovarian cancer screening unit in a teaching hospital.

SUBJECTS

22,000 volunteers, all postmenopausal women > or = 45 years of age; recruited between 1 June 1986 and 1 May 1990.

INTERVENTION

Surgical investigation if the ultrasound examination was abnormal.

MAIN OUTCOME MEASURES

Cumulative and relative risk of developing an index cancer (invasive epithelial cancer of the ovary or fallopian tube) after a specified CA 125 result.

RESULTS

49 index cancers developed in the study population during a mean follow up of 6.76 years. The overall cumulative risk of developing an index cancer was 0.0022 for the entire study population and was lower for women with a serum CA 125 concentration < 30 U/ml (cumulative risk 0.0012) but was appreciably increased for women with a concentration > or = 30 U/ml (0.030) and > 100 U/ml (0.149). Compared with the entire study population the relative risk of developing an index cancer within one year and five years was increased 35.9-fold (95% confidence interval 18.3 to 70.4) and 14.3-fold (8.5 to 24.3) respectively after a serum CA 125 concentration > or = 30 U/ml and 204.8-fold (79.0 to 530.7) and 74.5-fold (31.1 to 178.3) respectively after a concentration > or = 100 U/ml.

CONCLUSION

CA 125 is a powerful index of risk of ovarian and fallopian tube cancer in asymptomatic postmenopausal women.

Clinical implications of heterogeneity of tumor response to radiation therapy

Heterogeneity of response of tumor tissue to radiation clearly exists. Major parameters include histopathologic type, size (number of tumor rescue units (TRUs)), hemoglobin concentration, cell proliferation kinetics and immune rejection reaction by host. Further, normal and presumably tumor tissue response is altered in certain genetic diseases, e.g. ataxia telangiectasia. Any assessment of response of tumor tissue to a new treatment method or the testing of a new clinical response predictor is optimally based upon a narrow strata, viz., uniform with respect to known parameters of response, e.g. size, histological type. Even among tumors of such a clinically defined narrow strata, there will be residual heterogeneity with respect to inherent cellular radiation sensitivity, distributions of pO2, (SH), cell proliferation etc. The value of a response predictor of an individual tumor will be determined by the heterogeneity of values for these and or other characteristics and by the coefficient of variation (CV) of the measured values of the individual parameters. Heterogeneity of one or more parameters of response is reflected in the slope of the dose response curve for local control, viz. the greater the heterogeneity the less steep the slope. To examine for this effect, the slope of dose response curves for control of model tumors of 10(8) tumor rescue units (TRU) and the SF2 = 0.5 (survival fraction after a single dose of 2 Gy) has been used to assess the impact of inter- and intra-tumoral variation of SF2 on slope, defined as gamma 50 values. The gamma 50 is the increase in local control expressed in percent points for a one percentage increment in dose, at the mid-point on the dose-response curve. The gamma 50 was 6.5 for CV = 0.0. For inter-tumoral CVs of 10%, 20% and 40%, the gamma 50 rapidly decreased to 2.4, 1.3 and 0.7. Intra-tumoral variation was less important, viz., for CVs of 10%, 20%, and 40% the gamma 50 values were reduced to 5.3, 3.8 and 2.2. Combining inter- and intra-tumoral variation reduced the gamma 50 only slightly below that for inter-tumoral variation alone. For example, were the CV 10% for inter- and intra-tumoral variation, the gamma 50 would be 2.1 as compared to 2.4 for inter-tumoral variation alone. The number of TRUs also affects slope, viz. gamma 50 increased from 1 to 9.7 as the TRU number increased from 10(1) to 10(12).(ABSTRACT TRUNCATED AT 400 WORDS)

A dose response analysis of injury to cranial nerves and/or nuclei following proton beam radiation therapy

The low tolerance of the central nervous system (CNS) limits the radiation dose which can be delivered in the treatment of many patients with brain and head and neck tumors. Although there are many reports concerning the tolerance of the CNS, few have examined individual substructures of the brain and fewer still have had detailed dose information. This study has both. A three dimensional planning system was used to develop the combined proton beam/photon beam treatments for 27 patients with skull-base tumors. The cranial nerves and their related nuclei were delineated on the planning CT scans and the radiation dose to each was determined from three dimensional dose distributions. In the 594 CNS structures (22 structures/patient in 27 patients), there have been 17 structures (in 5 patients) with clinically manifest radiation injury, after a mean follow-up time of 74 months (range 40-110 months). From statistical analyses, dose is found to be a significant predictor of injury. Using logistic regression analysis, we find that, for each cranial nerve, at 60 Cobalt Gray Equivalent (CGE) the complication rate is 1% (0.5-3% with 95% confidence) and that the 5% complication rate occurs at 70 CGE (64-81 CGE with 95% confidence). The slope of the dose response curve (at 50%) is 3.2 (2.2-5.4 with 95% confidence). No significant relationship between dose and latency period for nerve injury was found.

Antigen-specific radioimmunoassays for anti-neutrophil cytoplasmic antibodies in the diagnosis of rapidly progressive glomerulonephritis

Circulating anti-neutrophil cytoplasmic antibodies (ANCA) have been described in most patients with "pauci-immune" necrotizing and crescentic glomerulonephritis. A 29-kDa serine protease (p29 or proteinase 3) and myeloperoxidase are the two best characterized antigens recognized by ANCA. The study presented here was conducted to define the diagnostic value of assays for antibodies against these two antigens in rapidly progressive glomerulonephritis. Radioimmunoassays were developed for anti-p29 and anti-myeloperoxidase antibodies, with purified antigens, and the results of the radioimmunoassays were compared with those obtained by immunofluorescence tests for ANCA. We performed assays on serum samples from 123 patients with the syndrome of rapidly progressive glomerulonephritis, as well as from 200 blood bank donors and from 717 additional control patients. Without knowledge of the results of ANCA tests, the renal pathologic findings in the 123 patients with rapidly progressive glomerulonephritis were analyzed, and 42 were classified as pauci-immune necrotizing and crescentic glomerulonephritis, 18 were classified as anti-glomerular basement membrane nephritis and 63 were classified as other forms of renal disease. We found radioimmunoassays to be more reliable in the diagnosis of pauci-immune necrotizing and crescentic glomerulonephritis than immunofluorescence testing. By radioimmunoassay, ANCA were found in 40 of 42 patients (95% sensitivity) with pauci-immune necrotizing and crescentic glomerulonephritis (14 with anti-p29 and 26 with anti-myeloperoxidase antibodies). The tests for antibodies to p29 and myeloperoxidase were 99.9 and 99.5% specific for pauci-immune necrotizing and crescentic glomerulonephritis, respectively. In the setting of rapidly progressive glomerulonephritis, a positive radioimmunoassay for anti-p29 or anti-myeloperoxidase antibodies (together with a negative test for anti-GBM antibodies) gives a probability of pauci-immune necrotizing and crescentic glomerulonephritis of over 99%.

Clinical interest in determinations of cellular radiation sensitivity

Determinations of cell sensitivity in terms of survival fraction after doses employed in clinical radiation therapy, say 1-3 Gy, are of increasing interest to clinicians as they provide direct experimental data which can be employed without reference to models of cell inactivation. SF2 values are expected ultimately to prove valuable as response predictors. Even so, SF2 values would surely be combined with other predictors also under development to give the best feasible estimate of response of tumor and normal tissue. There are, however, several concerns with the SF2 data currently available. These include: SF2 depends upon the cell system employed (established cell lines vs primary cultures) and the method of assaying survival fraction (colony formation vs population growth); dose-response curves for inactivation of tumors characterized by the reported distribution of SF2 values are, in many instances, not close to those judged to obtain in clinical practice; the broad distribution of SF2 values indicates a rather flatter dose-response curve for tumor control or normal tissue than seems true from clinical experience. There appears to be a potential for clinical gain by determination of sensitivity of normal tissues in order to identify patients who are of increased sensitivity (for example heterozygotes for AT, 5-oxoprolinuria, etc.). Although the absolute SF2 values obtained by current technologies of culturing human cells often appear to be poorly related to values expected from observed radiation response in patients, intensive research on cell viability assays will almost certainly yield more realistic results.

Vitreous hemorrhage after closed vitrectomy for proliferative diabetic retinopathy

The authors reviewed the medical records of 191 patients (232 eyes) who underwent closed vitrectomy for complications of diabetic retinopathy to evaluate the clinical picture of postvitrectomy hemorrhage (PVH). One hundred thirty-nine eyes (59.9%) had at least one episode of PVH (average, 1.5 per eye) that was variable in onset, not associated with a known cause in four fifths, with no noted source in two thirds, and severe in three fourths of the cases. Using logistic regression statistical analyses, the factors significantly associated with decreased incidence of PVH include older age of patient (P = 0.0004), long duration of surgery (P = 0.0002), and poor preoperative vision (P = 0.05). Of the 139 eyes with PVH, 65 (47%) had spontaneous clearing in an average of 11.3 weeks, 53 (38%) required repeat surgery, and 21 (15%) were inoperable, lost to follow-up, or refused reoperation. Postvitrectomy hemorrhage did not significantly influence the final visual outcome.

A morphometric study of the vascularity of oral squamous cell carcinomas and its relation to outcome of radiation therapy

In 26 patients the vascular morphology of pretreatment biopsies from oral squamous cell carcinomas (scc) was studied. Patients had been treated by radiation alone and followed up for 25-73 months. Vascular endothelial cells were identified using antifactor VIII staining. The distances from 700 randomly selected tumor cells to the closet blood vessel were measured in each tumor. Stepwise logistic regression analysis revealed that tumors with fewer than 21% of the morphologically intact tumour cells located within 48 microns of the closest blood vessel had a better control rate than tumors with a higher proportion of tumor cells within this distance. Using the analysis as a predictive assay, local tumor control was predicted from a single histological section with a sensitivity of 81% and a specificity of 60%. In correctly predicted cases of local control, the average median distance between tumor cells and blood vessels was 105 microns. These tumors formed well differentiated avascular tumor cell nests that were surrounded by stroma and blood vessels. Mitotic figures were observed only in the outer rim of cell nests while the center was often keratinizing or necrotic. In cases of correctly predicted treatment failures the average median distance from intact tumour cells to capillaries was 76 microns. These tumors showed varying degrees of organization and capillaries penetrating tumor cell areas. Clinical outcome of radiation therapy of oral scc appears to be correlated with different patterns of tumor architecture and blood supply.

Comparative morphometric study of tumor vasculature in human squamous cell carcinomas and their xenotransplants in athymic nude mice

When human tumor xenotransplants into nude mice are used as experimental models, it is important to know whether their microvascular anatomy is rather host or tumor specific. Therefore a morphometric comparison of the vascular network in human squamous cell carcinomas and their xenotransplants was carried out. Biopsies were taken from surgical specimens of three squamous cell carcinomas of the oral cavity. Part of the material was processed for histology and the rest was cut into 1-mm3 cubes and transplanted s.c. into the lateral thorax of athymic nude mice [NCr/Sed(nu/nu)]. The microvascular architecture of original tumors and of three first, one second, and one late generation xenografts was compared. Capillaries were identified in original human tumors by anti-factor VIII staining and in xenografts with antilaminin staining. The median distances between interphase tumor cells and blood vessels were determined and were found to be much longer in original human tumors than in xenografts, ranging from 81 microns to 99 microns and 53 microns to 65 microns, respectively. However, the characteristic qualitative histology of tumors appeared to be preserved in xenotransplants. Analysis of the topographic distribution of mitotic figures revealed that in both original tumors and xenotransplants proliferation of tumor cells was concentrated around blood vessels. Again, vascular distances in original tumors were significantly longer than in xenotransplants. In addition, xenotransplants into nude mice from a long passaged cell line from a human pharyngeal squamous cell carcinoma, FaDu, was investigated. FaDu showed a rare-fication of the capillary network with increasing tumor volume, but a constant median distance of mitotic figures from blood vessels. In conclusion, the pattern of spatial distribution of proliferating tumor cells as well as differentiation characteristics appear to be retained in xenograft tumors, but the density of the vascular system is host specific. This has to be taken into account when physiological parameters of blood supply are studied in xenotransplanted tumors.

Fractionated proton radiation therapy of chordoma and low-grade chondrosarcoma of the base of the skull

Sixty-eight patients with chordoma or low-grade chondrosarcoma at the base of the skull received fractionated high-dose postoperative radiation delivered with a 160-MeV proton beam. Protons have favorable physical characteristics which allow the delivery of high doses of radiation to these critically located tumors. The methods employed for these treatments are described. These patients have been followed for at least 17 months and for a median of 34 months. The median tumor dose was 69 CGE (cobalt Gy equivalent): CGE is the dose in proton Gy multiplied by 1.1, which is the relative biological effectiveness for protons compared to cobalt-60. The daily dose was 1.8 to 2.1 CGE. For this group the 5-year actuarial local control rate is 82% and disease-free survival rate is 76%. The incidence of treatment-related morbidity has been acceptable.

Effects of pentobarbital anesthesia on the energy metabolism of murine tumors studied by in vivo 31P nuclear magnetic resonance spectroscopy

The effects of pentobarbital anesthesia on the energy metabolism of FSaII and MCaIV foot tumors in mice were studied by 31P MRS. Using an 8.5 T spectrometer, in vivo spectra were obtained in 15 animals before and after pentobarbital anesthesia (0.05 mg/g ip). The average phosphocreatine/inorganic phosphate ratios (PCr/Pi) with and without pentobarbital were similar for both tumor histologies. Effects on individual tumors, however, were greater than 20% in 9/15 animals and greater than 50% in 6/15 animals. Pentobarbital anesthesia increased the variability of tumor intracellular pH, and the phosphomonoester/nucleotide triphosphate (PME/NTP) and nucleotide triphosphate/inorganic phosphate ratios (NTP/Pi). When examining the average in a cohort, pentobarbital anesthesia had no significant effect on the PCr/Pi, PME/NTP, NTP/Pi ratios or the pH. However, approximately equal to 50% of individual tumors do have significant changes in these parameters. The anesthesia-induced variability of tumor energy metabolism may explain the decrease in TCD50 observed in previous studies using multifraction radiation.

Use of a computer to group actinomycetes for studies on the ecology of soil microorganisms

A computer program has been prepared for grouping soil actinomycetes into cluster groups based on the presence or absence of aerial mycelium, the color of soluble pigment, and the shade of color of surface and reverse mycelium. The program automatically condenses cultures with wide ranges of characteristics into a limited number of groups and provides a permanent record so that comparisons can be made among experiments performed over a span of time. The program permits the grouping of large numbers of cultures with minimal laboratory effort and has proven useful in defining some of the ecological factors that lead to changed actinomycete populations in soils.