Fish schools: an asset to corals.

Schools of juvenile haemulid fish feed in sea grass beds at night. By day they rest over coral heads, where they excrete substantial quantities of ammonium and particulate nitrogen and phosphorus into the nutrient-poor waters. The percentages of these nutrients contributed by the fish were comparable to those from other sources. Coral heads with resident fish schools grew faster than those without resident schools, indicating that fish may be more beneficial to the corals than has been assumed.

Control of nitrogen export from watersheds by headwater streams.

A comparative (15)N-tracer study of nitrogen dynamics in headwater streams from biomes throughout North America demonstrates that streams exert control over nutrient exports to rivers, lakes, and estuaries. The most rapid uptake and transformation of inorganic nitrogen occurred in the smallest streams. Ammonium entering these streams was removed from the water within a few tens to hundreds of meters. Nitrate was also removed from stream water but traveled a distance 5 to 10 times as long, on average, as ammonium. Despite low ammonium concentration in stream water, nitrification rates were high, indicating that small streams are potentially important sources of atmospheric nitrous oxide. During seasons of high biological activity, the reaches of headwater streams typically export downstream less than half of the input of dissolved inorganic nitrogen from their watersheds.

New technologies in the radiotherapy clinic.

What are the limitations to the accuracy of our current technologies in radiation oncology? The immobilization of the patient, definition of the target, motion of the target and localization of the target are the major concerns that must be addressed. Current approaches to meet these needs have brought new technical systems with greater precision and new clinical procedures with higher expectations of practice. This text offers discussions on these issues, including advances in intensity-modulated radiotherapy planning, clinical target definition for the major tumor sites, management of organ motion, target localization and image guidance systems, and the expanding applications of high-precision treatment with stereotactic body radiotherapy.

The clinical efficacy of localized hyperthermia.

Localized hyperthermia alone can induce regressions in human neoplasms, but superior results can be obtained by integrating hyperthermia with even low doses of radiotherapy. Several clinical trials demonstrate that hyperthermia plus irradiation can produce higher tumor response rates than the same irradiation alone. While minimal enhancement of irradiation effects on normal tissues is reported, this may be due in part to the physical localization of the heating preferentially in tumors, often assisted by normal tissue cooling or shielding. These advantages may exist only in special circumstances in the treatment of deep tumor volumes. A variety of hyperthermia and irradiation fractionation schemes has been used; the optimal one(s) is yet to be clearly established. To date, no tumor histology has been shown to be more sensitive than another, although the relative radioresistance of melanomas, especially to smaller fraction sizes, is substantially offset by the addition of hyperthermia. Larger tumor volumes are more difficult to heat and achieve lower response rates, but may be relatively less problematic for combined hyperthermia and irradiation than for irradiation alone. Currently used microwave and unfocused ultrasound applicators, when used singly, usually achieve potentially therapeutic temperatures to only about 2- to 4-cm depth, although site-specific tissue characteristics may greatly alter this in individual circumstances. Anatomical factors limit the number of sites which can be usefully treated because of inflexibilities of the currently available equipment. Single-point temperature measurements during treatment correlate poorly with tumor response, while minimum mean tumor temperatures may correlate more strongly. Local and radicular pain occurs commonly during treatment, superficial burns occur occasionally, but major tissue complications have been reported rarely. While the efficacy of localized hyperthermia in augmenting tumor responses to irradiation with acceptable toxicity is established, much important clinical work remains to be done in carefully defined treatment protocols.

Tumor responses following multiple hyperthermia and X-ray treatments: role of thermotolerance at the cellular level.

We have investigated the effect of increasing numbers of hyperthermia fractions given at 7-day intervals, with or without fractionated radiotherapy, on tumor cure, tumor growth, and cell survival after in vivo or in vitro heat. The murine RIF tumor was treated by capacitive radiofrequency hyperthermia at 44.0 degrees C for 20 min for one to five treatments at weekly intervals (1-5 wk D1). Single treatments (1 wk D1) induced cure in 5% of tumors. Additional treatments (2-5 wk D1) induced similar rates of cure (0-16%, P greater than 0.05 for 1 wk versus 2, 3, 4 or 5 wk D1). 1 wk D1 resulted in marked growth delay compared to controls. Mean tumor diameter doubling times increased from 13.2 days to 27.5 days (P less than or equal to 0.01). 2-5 wk D1 induced little additional growth delay (doubling times, 27.8-32.3 days, P greater than 0.05 for 1 wk versus 2, 3, 4 or 5 wk D1). Fractionated radiotherapy of 3200 rads (400 rads given twice each week) significantly prolonged mean tumor doubling time to 26.2 days. The addition of one hyperthermia session to the fractionated radiotherapy (1 wk D1 + XRT) further increased doubling time to 34.2 days (P less than or equal to 0.01). Additional treatments (2-5 wk D1 + XRT) only modestly increased doubling times (36.0-39.5 days, P greater than 0.05 for 1 wk versus 2, 3, 4 or 5 wk D1). In vitro assay of cells dissociated from tumors 5, 10, or 15 days after 3 wk D1 showed increased survival to 44 degrees C compared to previously untreated controls, and this cellular thermoresistance proved to be transient and noninheritable (i.e., thermotolerance). These results indicate that tumors can develop a prolonged thermal resistance after multiple weekly treatments which significantly modifies the response to subsequent treatment and which is associated with cellular thermotolerance.

Heat-induced protection of mice against thermal death.

The possibility that the exposure of organisms to whole-body hyperthermia may provide protection against subsequent thermal exposures is intriguing and may play an important role in the clinical scheduling of fractionated hyperthermia. We used C3H mice to investigate whether whole-body heating can be used as a conditioning treatment to induce protection of mice against thermal death from a subsequent heat treatment. Our data clearly show that a conditioning whole-body heat dose (41 degrees for 40 min), by itself nonlethal, can give substantial protection to animals against a later heat treatment. The heat-induced protection is transient in nature: it reaches a maximum by 6 to 24 hr following the 41 degrees conditioning dose and decays by approximately 60% by 72 hr. The data presented do not shed any light on the cause of death following whole-body hyperthermia. Our results show clearly that the response of a complex organism to heat can be altered by previous heat exposure.

Thermal sensitivity and thermotolerance in normal porcine tissues.

We have previously presented a histopathological grading scheme for thermal damage in normal porcine adipose and skeletal muscle tissues. Here we have used this scheme to assess the heat sensitivity of these tissues, and evaluate the protective benefit of thermotolerance as induced by a prior thermal exposure. Tissues were exposed to temperatures ranging from 40-50 degrees for 30 min. Half of all sites also received a thermal exposure of 41.0-43.0 degrees 4 hr earlier. Biopsies for histological evaluation were obtained at 18 to 24 hr ("acute") and at 28 to 31 days ("chronic") following treatment. Only mild acute injury was seen in the early samples, following either single or double heat exposures, at all temperature levels. Minimal chronic damage was also seen in the late samples following single exposures of 45 degrees or less. Higher single exposures caused important chronic lesions, the severity of which was dose dependent. Regions that had received the earlier conditioning thermal exposure showed a significant protection against the subsequent thermal exposure. In such regions, mean (chronic) pathology scores were reduced by 76 to 86% over the temperature range 45-48 degrees. The degree of acute damage failed to predict the degree of chronic damage. Overall, induction of thermotolerance provided an advantage of 2 degrees or more in normal tissue protection.

Anatomical site-specific modalities for hyperthermia.

The clinical application of hyperthermia in the treatment of deep-seated tumors remains an empirical science. The pleomorphic nature of the neoplasms and the great diversity in the anatomy and physiology of the individual tumor locations make the treatment of nearly every neoplasm a unique challenge. A wide variety of devices is required, both for the administration of hyperthermia and for the measurement of the temperatures achieved. At Stanford University, these include the BSD Medical Corp. annular phased array system, an isospherical ultrasound device, and interstitial radiofrequency for deep heating. Ultrasound transducers and a variety of microwave applicators are used for superficial hyperthermia. Six illustrative case studies, selected from the 91 patients treated in our program since October 1981, are presented, with discussion and comparison of treatment devices. Difficulties in deep heating were encountered in several instances, believed secondary to the thickness of the s.c. fat, the relatively high heat-induced tumor blood flow, and the presence of adjacent bone. It is suggested that ultimate improvement in clinical results will be possible once a better understanding is achieved of such anatomical and physiological factors.

Calcification inhibitors in rat and human serum and plasma.

Rat and human serum and plasma were shown to contain considerable amounts of calcium phosphate precipitation inhibitors. Two general classes of inhibiting molecules were observed for both species: high molecular weight (approx. 30 000-200 000) and low molecular weight (less than 1000). The high molecular weight components eluted from a Bio-Gel P-200 column in two peaks, one at approx. 158 000 and a broader peak at approx. 43 000. The identity of these inhibitors is unknown at present. Low molecular weight inhibitors include magnesium, pyrophosphate, and citrate ions and at least one unidentified component that coelutes with pyrophosphate and citrate on a Bio-Gel P-4 column. Quantitatively, most of the inhibitor activity resides in the high molecular weight components and it is possible that it is this activity which is responsible for maintaining the metastability of the circulating fluids. The role of the low molecular weight components may be to regulate calcification at sites inaccessible to high molecular weight molecules.

Histamine phase shifts the hamster circadian pacemaker via an NMDA dependent mechanism.

The SCN acts as the central pacemaker for circadian rhythms in mammals. Histamine has been shown to affect circadian rhythms both in vivo and in vitro. We investigated the mechanism by which histamine phase shifts circadian rhythms in vitro. Hypothalamic slices containing the SCN were prepared from golden hamsters, and spontaneous firing rates of individual cells were recorded on the second day in vitro. Application of histamine (1 microM-10 mM) at the extrapolated time of 2 h after lights off (ZT 14) on day 1 in vitro delayed the time of peak firing in a dose-dependent manner. Pre-exposure to the N-methyl-D-aspartate (NMDA) receptor antagonist (+/-)-2-amino-5-phosphonopentanoic acid (AP-5; 100 microM-1 mM) 5 min before histamine (1 microM) was applied to the slice blocked the phase-delaying effects of histamine. Application of the H1 blocker mepryamine (100 nM) or the H2 blocker cimetidine (10 microM) followed by histamine had no effect on the phase delay induced by histamine. In whole cell recordings from acutely dissociated neurons of hamster SCN, histamine (50 microM) was shown to potentiate NMDA-evoked currents by 52 +/- 12%. These experiments demonstrate that histamine phase shifts of the circadian clock are dependent on NMDA receptor activation and that histamine can directly potentiate NMDA currents in SCN neurons. Histamine may alter circadian clock function by acting directly on NMDA receptors, possibly via binding to the polyamine site.

The significance of thermotolerance after 41 degrees C hyperthermia: in vivo and in vitro tumor and normal tissue investigations.

We have investigated the development of thermotolerance in both tumors and normal tissues after 41 degrees C for durations as brief as 15 minutes. The murine RIF tumor, treated by both local radiofrequency and systemic methods, was assayed for thermotolerance by both tumor growth and cell survival analyses. The murine leg and ear, treated by conductive methods, were assayed using pre-defined tissue damage scoring systems. All of these treatments quickly induced substantial levels of thermotolerance. In the tumor studies using local heating, RIF mean diameter doubling time decreased from 17.8 days to a minimum of 13.0 days with a 9 hr interval between 41.0 degrees C for 15 minutes and 44.0 degrees C for 30 minutes (9 hr D1-D2); cell survival increased from 1.2 X 10(-2) to 3.4 X 10(-1) (same interval). Both assays showed some degree of tolerance present immediately after 41.0 degrees C for 15, 30 or 60 minutes (0 hr D1-D2). In the tumor studies using systemic heating, the kinetic pattern of the induced tolerance was similar to that observed after local heating. In the leg studies, 41.0 degrees for 30 minutes increased the time at 45 degrees C necessary to induce a specified level of tissue damage (mean score of 7) by a maximum of 1.8 times (24 hr D1-D2). The kinetic pattern was similar to that for the tumors. In the ear studies, 41.0 degrees C for 30 minutes increased the time at 45 degrees C necessary to induce ear necrosis in 50% of animals by a maximum of 3.5 times (48 hr D1-D2). The peak tolerance level occurred later for the ears, which have a lower normal temperature of 28-30 degrees C, than for the tumors or legs. These results indicate that: thermotolerance can begin to appear in tumors during treatment if hyperthermia sessions involve initial low thermal exposures (near 41 degrees C) for 15 minutes or longer; thermotolerance can develop in tumors after systemic heating and occurs with a kinetic pattern similar to that following local heating; and normal tissues also can develop high levels of thermotolerance after similar thermal exposures.

Parameters predictive for complications of treatment with combined hyperthermia and radiation therapy.

Pretreatment and treatment related factors were reviewed for 996 hyperthermia sessions involving 268 separate treatment fields in 131 patients managed with hyperthermia for biopsy confirmed local-regionally advanced or recurrent malignancies to ascertain parameters associated with the development of complications. A subset of 249 fields were identified in which multipoint or mapped temperature data were available for at least one treatment session per field. A total of 198 fields involved superficially located tumors (less than or equal to 3 cm from the surface), whereas 51 fields involved more deeply located tumors. Most of these patients had received extensive prior therapy: 77% had surgery, 75% chemotherapy, 65% radiation therapy and 28% hormonal therapy. They were treated with hyperthermia in conjunction with radiation therapy (244 fields) or hyperthermia alone (5 fields). The hyperthermia treatment objectives were to elevate intratumoral temperatures to a minimum of 43.0 degrees C for 45 minutes while maintaining maximum normal tissue temperatures to less than or equal to 43 degrees C and maximum intratumoral temperatures to less than or equal to 50 degrees C. The hyperthermia was given within 30 to 60 minutes following radiation therapy without the administration of additional analgesics. Hyperthermia treatment regimens using radiative electromagnetic, ultrasound, or radiofrequency interstitial techniques were individualized, with 3 to 4 days between hyperthermia treatments and an average of 3.6 treatments (range 1-14; standard deviation 2.2) utilized per field. A total of 38 complications in 33 treatment fields were noted; an incidence of 27/198 (13.6%) for fields with superficially located tumors, and 6/51 (11.8%) in fields with more deeply located tumors. Univariate analyses demonstrated statistically significant correlations between the maximum tumor temperature (p = 0.0005), average of the maximum tumor temperatures (p = 0.0006), the average of the % tumor temperatures greater than 43.5 degrees C (p = 0.0071), and the average number of hyperthermia treatments (p = 0.033), with the development of complications. The average of the maximum measured tumor temperature for fields without complications was 44.6 degrees C compared with 45.9 degrees C for fields with complications. The complication rate increased from 7.5% (9/120) in fields that received one or two hyperthermia treatments to 18.6% (24/129) in fields that received greater than two hyperthermia treatments. Multivariate logistic regression analyses revealed the best bivariate model predictive of the development of complications included average of the maximum tumor temperature and the number of treatments per field (p = 0.00012 for the bivariate model).(ABSTRACT TRUNCATED AT 400 WORDS)

Two or six hyperthermia treatments as an adjunct to radiation therapy yield similar tumor responses: results of a randomized trial.

From March 1984 to February 1988, 70 patients with 179 separate treatment fields containing superficially located (less than 3 cm from surface) recurrent or metastatic malignancies were stratified based on tumor size, histology, and prior radiation therapy and enrolled in prospective randomized trials comparing two versus six hyperthermia treatments as an adjunct to standardized courses of radiation therapy. A total of 165 fields completed the combined hyperthermia-radiation therapy protocols and were evaluable for response. No statistically significant differences were observed between the two treatment arms with respect to tumor location; histology; initial tumor volume; patient age and pretreatment performance status; extent of prior radiation therapy, chemotherapy, hormonal therapy, or immunotherapy; or concurrent radiation therapy. The means for all fields of the averaged minimum, maximum, and average measured intratumoral temperatures were 40.2 degrees C, 44.8 degrees C, 42.5 degrees C, respectively, and did not differ significantly between the fields randomized to two or six hyperthermia treatments. The treatment was well tolerated with an acceptable level of complications. At 3 weeks after completion of therapy, complete disappearance of all measurable tumor was noted in 52% of the fields, greater than or equal to 50% tumor reduction was noted in 7% of the fields, less than 50% tumor reduction was noted in 21% of the fields, and continuing regression (monotonic regression to less than 50% of initial volume) was noted in 20% of the fields. No significant differences were noted in tumor responses at 3 weeks for fields randomized to two versus six hyperthermia treatments (p = 0.89). Cox regression analyses were performed to identify pretreatment or treatment parameters that correlated with duration of local control. Tumor histology, concurrent radiation doses, and tumor volume all correlated with duration of local control. The mean of the minimum intratumoral temperatures (less than 41 degrees C vs. greater than or equal to 41 degrees C) was of borderline prognostic significance in the univariate analysis, and added to the power of the best three covariate model. Neither the actual number of hyperthermia treatments administered nor the hyperthermia protocol group (two versus six treatments) correlated with duration of local control. The development of thermotolerance is postulated to be, at least in part, responsible for limiting the effectiveness of multiple closely spaced hyperthermia treatments.

Gastroscopic removal of an adjustable gastric band after partial intragastric migration.

BACKGROUND: Laparoscopic implantation of an adjustable gastric band is being performed widely. One potential complication is the transgastric migration of the band, that should be extracted. METHODS: The authors report a series of 182 patients, followed prospectively, October 1996 - April 2002, who had undergone insertion of the Swedish adjustable gastric band. All implantations had been completed by laparoscopy alone. RESULTS: There were no deaths. 15 complications were detected, of which 7 were intragastric migrations of the band (3.8%) at an average follow-up of 40 months. 6 were treated successfully by gastroscopy only, with a new cutter device and without complications. CONCLUSION: The endoscopic technique is beneficial even when the intraluminal migration is partial.

The influence of fluoride on apatite formation from unstable supersaturated solutions at pH 7.4.

The present study was undertaken to examine the effect of fluoride on the formation of apatite in aqeous calcium phosphate suspensions prepared by spontaneous precipitation at pH 7.4. The most notable finding was that fluoride greatly curtailed or eliminated the appearance of octacalcium phosphate-like precursor phases in these preparations.

Whole-lung irradiation for Kaposi's sarcoma.

Twenty-five patients were treated with whole-lung irradiation for symptomatic pulmonary KS. Treatment was most often given four days per week, 150 cGy per fraction, to 1050-1500 cGy (mean 1224 cGy). No acute toxicity was observed. 89% of patients completing therapy reported improvement in dyspnea. All patients responding symptomatically could reduce (and 78% could eliminate) oxygen use. Chest x-rays showed concurrent improvement in 78% of cases, although this was > or = 50% clearance of infiltrate in only 28%. Symptomatic improvement was prompt, always occurring during the 2-2 1/2 week therapy course. Clinical response was transient in some patients, but 12 weeks after therapy 56% remained symptomatically improved. Pulmonary KS indicated an advanced stage of AIDS and survival was short (mean: 15.7 weeks after completion of therapy). Patients with poor performance status (Karnovsky: < or = 30%) and progression of disease despite chemotherapy had very short survival (mean: 3.2 weeks). For such patients, a supportive care only approach without radiotherapy is suggested. For others, whole-lung irradiation provides prompt symptomatic improvement for most patients, and offers a simple treatment approach with little toxicity for often debilitated patients.

Nasopharyngeal carcinoma. A study examining Asian patients treated in the United States.

From 1972 to 1991, 126 Asian patients with nasopharyngeal carcinoma underwent definitive radiation therapy for locoregional disease: 86 men, 40 women. Median age was 50. All patients received external-beam irradiation with cobalt 60 or 4-18 MV x-rays. Local recurrence, regional recurrence, and distant metastases were 22%, 11%, and 23%, respectively. Local recurrence progressively increased with increasing T stage, but doses in those who recurred did not differ from the group as a whole. Regional recurrence was not associated with T or N stage or dose. Patients with N2 disease had the highest distant metastatic rate. The 5- and 10-year overall survival rates were 54% and 38%, respectively. Of age, gender, and histology, only age less than 50 was found to be favorably prognostic. No severe long-term complications were observed, and acute reactions were acceptable. Our survival results are comparable with results found both in Asia and North America. Nonetheless, altered fractionation techniques and/or other radiation modalities should be further explored to improve locoregional control.

The effects of hyperthermia on normal mesenchymal tissues. Application of a histologic grading system.

The alterations produced by radiofrequency-induced hyperthermia of 42 to 48 degrees C for 30 minutes were studied in the subcutaneous adipose tissue and skeletal muscle of swine. Acute lesions (18 to 24 hours) included edema, hemorrhage, necrosis (predominantly of myocytes) and granulocytic exudate in fat or muscle. The most important chronic lesion (28 to 31 days) was fibrosis replacing either tissue. There was a histiolymphocytic exudate with foreign-body giant cells around large lipid vacuoles. Muscle necrosis persisted and there was variable myocyte regeneration. Several specimens showed deep necrosis and abscesses. A grading system was developed to quantitate independently acute and chronic damage in each tissue. Acute lesions were usually less severe and extensive than chronic ones, without obvious dose response. Chronic lesions showed clearly a dose response, which began at 43 degrees C and increased with temperature. The latter appear to be reliable indicators of hyperthermic damage in deep soft tissues.

Preclinical feasibility study of NMP179, a nuclear matrix protein marker for cervical dysplasia.

OBJECTIVE: To evaluate, in a preclinical feasibility study, the efficacy of NMP179, a monoclonal antibody recognizing a cervical tumor-associated nuclear matrix antigen, for the early detection of high and low grade cervical intraepithelial neoplasia. STUDY DESIGN: In a blind study involving two clinical sites, NMP179 immunocytochemical staining data from 261 cervicovaginal Thin-Prep specimens were evaluated. Assay sensitivity and specificity were calculated based upon a positive threshold of > 10 immunostained cells per case, using cytologic diagnosis as an end point. RESULTS: Based upon the examination of squamous epithelial cells, NMP179 detected 96.7% of cases with cytologically diagnosed high grade squamous intraepithelial lesions (HSIL) and 70.5% of low grade squamous intraepithelial lesions. The antibody also reacted with 29.6% of normal (within normal limits or benign cellular changes) smears. CONCLUSION: The NMP179 assay detected HSIL with very high accuracy (96.7%). The assay was 79.3% sensitive for the detection of low and high grade cervical intraepithelial neoplasia (grades 1-3), with a specificity of 70.4%. NMP179 may be an effective marker for the early detection of preneoplastic squamous intraepithelial lesions of the cervix and may be useful as an adjunctive tool for better management of cervical intraepithelial neoplasia.

Identification of the target of monoclonal antibody A6H as dipeptidyl peptidase IV/CD26 by LC MS\MS.

The monoclonal antibody (MAb) A6H, originally developed to fetal renal tissues, was found to be highly reactive to renal cell carcinoma and was subsequently demonstrated to co-stimulate a subpopulation of T cells. The A6H antigen had not been identified heretofore. Antigen from detergent extracts of renal cell carcinoma cells (7860) was immunoabsorbed with A6H-agarose, and the resin-bound proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The antigen had a molecular weight of approximately 120 kDa as determined by Western blots. The 120-kDa protein band was excised and subjected to in-gel tryptic digestion, and the resulting peptides were separated and analyzed by liquid chromatography tandem mass spectrometry (LC MS\MS). The tandem mass spectra of the eluting peptides were used in combination with the SEQUEST computer program to search a human National Cancer Institute (NCI) protein database for the identity of the protein. The target antigen was shown to be dipeptidyl peptidase IV (DPP IV), which is also known as the cluster differentiation antigen CD26. Flow analysis of the expression of the A6H antigen and of CD26 on 7860 cells and on peripheral blood lymphocytes supported the identification of the A6H antigen as DPP IV. Recognition that the A6H antigen is DPP IV/CD26 afforded the opportunity to compare previous studies on A6H with those on other anti-CD26 antibodies in terms of expression in cancer cell lines and various tissues and as co-stimulators of T-cell activation.