Dexamethasone-induced tumor lysis syndrome in high-grade non-Hodgkin's lymphoma

Tumor lysis syndrome is a catastrophic complication of the treatment of certain neoplasms. It most commonly occurs in association with hematologic malignancies and manifests a few hours to a few days after initiation of specific chemotherapy. It has rarely been encountered as a complication of steroid therapy only. Tumor lysis syndrome is a potentially fatal condition if it is not recognized promptly and managed aggressively. We report on a patient with high-grade non-Hodgkin's lymphoma who developed severe metabolic acidosis, hyperkalemia, hyperphosphatemia, and hypocalcemia within 2 days of starting corticosteroid therapy. He was managed with intravenous fluids, bicarbonate infusion, calcium gluconate, and 25% dextrose with insulin. He did not respond to these measures and died within a few hours of the diagnosis of tumor lysis syndrome. Increasing awareness of this complication and proper prophylactic measures are necessary to improve the outcome.

Boronated starburst dendrimer-monoclonal antibody immunoconjugates: evaluation as a potential delivery system for neutron capture therapy

Boron neutron capture therapy (BNCT) is based on the nuclear capture reaction that occurs when boron-10, a stable isotope, is irradiated with low-energy or thermal neutrons (< or = 0.025 eV) to yield high LET alpha particles and recoiling 7Li nuclei [10B + nth-->[11B]-->4He(alpha) + 7Li + 2.39 MeV]. Approximately 10(9) boron-10 atoms must be delivered to each target cell in order to sustain a lethal 10B(n,alpha)7Li reaction. If MoAbs are to be used for targeting boron-10, then it is essential that they recognize a surface membrane epitope that is highly expressed on tumor cells and that a large number of boron-10 atoms be attached to each antibody molecule. In order to heavily boronate MoAbs, we have utilized starburst dendrimers (SD), which are precise, spherical macromolecules composed of repetitive poly(amidoamino) groups. Second- and fourth-generation dendrimers, having 12 and 48 reactive terminal amino groups and molecular weights of 2414 and 10,632 Da, respectively, were boronated using an isocyanato polyhedral borane, Na(CH3)3NB10H8NCO. The boronated starburst dendrimers (BSD), in turn, were derivatized with m-maleimidobenzoyl N-hydroxysulfosuccinimide ester (sulfo-MBS). The MoAbIB16-6, which is directed against the murine B16 melanoma, was derivatized with N-succinimidyl 3-(2-pyridyldithio)propionate (SPDP). The MBS-derivatized BSD and SPDP-derivatized MoAb were reacted to yield stable immunoconjugates.(ABSTRACT TRUNCATED AT 250 WORDS)

Experience of haemodialysis at the Kidney Centre

Seventy-nine patients of end stage renal disease (ESRD) on maintenance haemodialysis were studied. Most of the cases were in their prime of life. The disease was equally common in both sexes and all ethnic groups. Chronic glomerulonephritis was the commonest cause followed by diabetes mellitus. Hypertension was the commonest associated illness. All patients were screened for hepatitis B surface antigen and antibody and those found negative were vaccinated. A-V fistula in the upper extremity was used as the vascular access in 93% cases. In 68% cases dialyzer was reused without any ill effect. Amongst the complications observed, hypotension was seen in 65%, psychological disorders in 52%, followed by nausea, vomiting, itching and cramps. Technical complications were related to A-V fistula in 45% cases. Forty three percent patients were maintained without blood transfusion and 88% showed improvement in their quality of life.

Determination of boron in tissues and cells using direct-current plasma atomic emission spectroscopy

We have developed a safe, simple, and efficient method for boron determination by means of direct-current plasma atomic emission spectroscopy. Tissues were solubilized by using concentrated sulfuric acid and 70% hydrogen peroxide to digest the samples without the need of high temperatures and pressures. Boron cluster compounds could be measured with sensitivity, precision, and accuracy similar to those of boric acid standards. Results obtained with [(C2H5)3NH]2B12H12, Cs2B12H11SH.H2O, and C15H32B10O6 show that this analytical method is applicable to a variety of compounds with different chemical structures. A sensitivity of 0.1 ppm has been obtained with known standards alone and in a variety of tissue matrices including tumor, blood, liver, skin, and cell suspensions. The measurement of total boron by direct-current plasma atomic emission spectroscopy (DCP-AES) has been achieved with as little as 50 mg of tissue or as few as 5 x 10(7) cells. The procedure is applicable to the analysis of boron in the ppm range with a high degree of precision and accuracy.

Epidural spinal cord compression from metastatic cancer: clinical features and management

We retrospectively analyzed thirty-three patients (21 males, 12 females) with malignancy induced spinal cord compression (SCC). The mean age of the patients was 42.8 years and almost half (51%) of them presented with SCC. Mean duration of symptoms was 4.5 months and the mean interval between the original diagnosis of cancer and the development of SCC was 14.6 months. Back pain was the most frequent (97%) symptom with an equal number of patients having subjective or objective evidence of lower limb weakness. Majority (73%) of the patients were non-ambulatory at the time of diagnosis. Spinal level involvement was mostly thoracic (62%) followed by lumber (38%). Breast cancer was the commonest underlying malignancy (21%). Lung (12%), prostrate (12%), multiple myeloma (9%), and carcinoma with unknown primary (12%) were also frequently encountered. There was an overall response rate of 22% to the therapeutic interventions: mostly observed in the ambulatory patients. Only 7% of the non-ambulatory patients regained ability to walk. None of the responders had bladder or bowel dysfunction. Twenty-two percent of the responders are still ambulatory with a mean follow-up of six months.

Clinical features and management of malignant ascites

Retrospective analysis of 45 patients (33 females, 12 males) with cytologically-proven malignant ascites is presented. Abdominal pain was the most frequent symptom (69%). Fiftythree percent cases had low serum albumin. Ascitic fluid was haemorrhagic or serosanguinous in 48% cases, in the rest it was clear or straw-coloured. Peritoneal effusion was exudative in 84% cases. Mean glucose content of ascitic fluid was 95 mg/dl and the mean white cell count of 919 cells/cmm. Vast majority (82%) of the cases had metastatic adenocarcinomas. Primary malignancy was mostly ovarian (47%) followed by non-Hodgkin's lymphoma (11%) and gall bladder carcinoma (9%). Primary site could not be identified in 13% cases. Sixty-two percent patients received systemic chemotherapy for the underlying malignancy, of these 43% had complete or partial resolution of the ascites. Of the patients whose long-term follow-up is available, 54% were alive with a median follow-up of 9 months.

Boron neutron capture therapy of a rat glioma

The purpose of the present study was to utilize a well-established rat glioma to evaluate boron neutron capture therapy for the treatment of malignant brain tumors. Boron-10 (10B) is a stable isotope which, when irradiated with thermal neutrons, produces a capture reaction yielding high linear energy transfer particles (10B + 1nth----[11B]----4He(alpha) + 7Li + 2.79 MeV). The F98 tumor is an anaplastic glioma of CD Fischer rat origin with an aggressive biological behavior similar to that of human glioblastoma multiforme. F98 cells were implanted intracerebrally into the caudate nuclei of Fischer rats. Seven to 12 days later the boron-10-enriched polyhedral borane, Na2B12H11SH, was administered intravenously at a dose of 50 mg/kg body weight at varying time intervals ranging from 3 to 23.5 hours before neutron irradiation. Pharmacokinetic studies revealed blood 10B values ranging from 0.33 to 10.5 micrograms/ml depending upon the time after administration, a T1/2 of 6.2 hours, normal brain 10B concentrations of 0.5 microgram/g, and tumor values ranging from 1.1 to 12.8 micrograms/g. No therapeutic gain was seen if the capture agent was given at 3 or 6 hours before irradiation with 4 x 10(12) n/cm2 (10 MW-min; 429 cGy). A 13.5-hour preirradiation interval resulted in a mean survival of 37.8 days (P less than 0.01), compared to 30.5 days (P less than 0.03) for irradiated controls and 22.1 days for untreated animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Boron neutron capture therapy: linkage of a boronated macromolecule to monoclonal antibodies directed against tumor-associated antigens

Two new protein-binding polyhedral boron derivatives, isocyanatoundecahydro-closo-dodecaborate(2-) (1) and isocyanato(trimethylamino)octahydro-closo-decaborate(1 -) (2), were synthesized. These anionic isocyanates have long hydrolysis half-lives at pH 7 and react readily with primary or secondary aliphatic amines resulting in spontaneous urea linkage. Utilizing 1, 1100 boron atoms (7.3% boron by weight) were incorporated per molecule of a polyclonal antibody directed against human thymocytes (anti-thymocyte globulin) without denaturation. However, immunoreactivity of the conjugates was lost. Reaction of 1 and 2 with polylysine yielded boronated macromolecules containing 21-28% boron by weight (up to 2000 boron atoms per molecule). Polylysine boronated with 2 was successfully linked to antibody molecules employing the heterobifunctional linking molecules N-succinimidyl 3-(2-pyridyldithio)propionate (SPDP) and m-maleimidobenzoyl sulfosuccinimide ester (sulfo-MBS). Separation of the conjugated antibody from the free boronated macromolecules and unconjugated antibody molecules has been achieved by gel filtration on a Sephacryl S-300 column. By linking boronated polylysine to antibodies, greater than 10(3) boron atoms were incorporated with the attachment of this species to one or more sites on the antibody molecule. The resulting immunoconjugates contained greater than 10(3) boron atoms per molecule, retained their immunoreactivity, and potentially might be useful for the selective delivery of large numbers of boron atoms to tumor cells.

Electron spectroscopic imaging for high-resolution immunocytochemistry: use of boronated protein A

In the present study we adapted electron spectroscopic imaging (ESI) for high-resolution immunocytochemistry. To accomplish this, we applied boronated protein A (B-pA) for indirect detection of specific antigenic sites using pre-embedding and post-embedding protocols. Isolated acinar cells were exposed to wheat germ agglutinin (WGA) and anti-WGA, followed by B-pA, to reveal WGA binding sites at the level of the plasma membrane. The cells were then embedded in Epon and unstained ultra-thin sections were examined by electron microscopy using the ESI mode. For post-embedding, ultra-thin sections of glutaraldehyde-fixed, Lowicryl-embedded pancreatic tissue were exposed to specific antibodies (anti-insulin or anti-amylase), followed by B-pA. The unstained sections were examined using the ESI mode. In both cases, boron was detected with high resolution either at the level of the plasma membrane of acinar cells, demonstrating WGA binding sites, or over secretory granules in pancreatic insulin-secreting cells or acinar cells, demonstrating insulin and amylase, respectively. These findings were compared to those obtained with the protein A-gold technique, and have demonstrated the analogy of both types of labeling. In addition, several control experiments assessed this novel approach. They have demonstrated the specificity of labeling and the high reactivity of B-pA, as well as its antibody-binding properties. Finally, electron energy loss spectral analysis confirmed the presence of boron in the tissue sections at sites where immunolabeling was detected. These results demonstrate that ESI is an appropriate approach for cytochemistry. Since the technique is based on detection of elements, spatial resolution is considered to be in the magnitude of 0.5 nm, which represents a major improvement in resolution over actual electron microscopic cytochemical techniques.

Pre-clinical studies on boron neutron capture therapy

The present report provides an overview of the multidisciplinary research effort on BNCT that currently is in progress at The Ohio State University. Areas under investigation include the preparation of boron containing monoclonal antibodies, the synthesis of boron containing derivatives of promazines and phathalocyanines, the development of a rat model for the treatment of glioblastoma by means of BNCT, the design of an accelerator-based neutron irradiation facility, and 10B concentration measurements using alpha track autoradiographic methods. Progress in each of these areas is described and the direction of future research is indicated.

Boronation of antibodies with mercaptoundecahydro-closo-dodecaborate(2-) anion for potential use in boron neutron capture therapy

The anionic polyhedral borane derivative, mercaptoundecahydro-closo-dodecaborate(2-), has been evaluated as a boronating agent for antibodies. The objective of these studies was the selective delivery of boron to neoplasms for neutron capture therapy. Incubation of a large excess of this anion with the polyclonal antibody antithymocyte globulin (ATG) resulted in the incorporation of 9-13 mol of the anion per mol of antibody. The extent of boron incorporation into the protein was measured either by tritium-labeled B12H11SH2- or by direct boron determination with neutron activation analysis. The nature of the covalent linkage of the anion to the antibody appeared to involve the formation of a new disulfide bond by a thiol-disulfide exchange. The number of boron atoms incorporated into antibodies by this method appeared to be inadequate for neutron capture therapy. However, such boronated antibodies may have potential for the detection of molecules of biologic interest by means of electron energy loss spectroscopy.

Boronated monoclonal antibody 17-1A for potential neutron capture therapy of colorectal cancer

The theoretical basis for boron neutron capture therapy (BNCT) derives from the reaction that occurs when a stable isotope, boron-10, is irradiated with thermal neutrons to produce an unstable intermediate, boron-11, which then undergoes instantaneous nuclear fission to yield lithium-7 and alpha particles.

Dicesium N-succinimidyl 3-(undecahydro-closo-dodecaboranyldithio)propionate, a novel heterobifunctional boronating agent

The synthesis of a novel heterobifunctional agent, dicesium N-succinimidyl 3-(undecahydro-closo-dodecaboranyldithio)propionate, is described. This structure contains an active ester component known to react rapidly under very mild conditions with amino groups of proteins, resulting in covalent linkage. With use of this boronating agent, approximately 480 boron atoms have been incorporated per molecule of a polyclonal antibody directed against human thymocytes and 1300 boron atoms per molecule were incorporated into a monoclonal antibody, 17-1A, directed against human colorectal carcinoma cells. Binding of the boronated antibodies to the corresponding target cells was demonstrated by means of membrane immunofluorescence. There was some loss in reactivity, as determined by fluorescent end point titers, but specificity remained unchanged. The data suggest that boronated antibodies potentially could be used to selectively deliver boron-10 to tumor cells in order to achieve their destruction by neutron capture.