Development of colonic adenocarcinomas in a mouse model of ulcerative colitis

Mice deficient in both interleukin-2 and beta 2-microglobulin expression (Beta 2mullnull x IL-2null mice) develop an inflammatory disease of the colon resembling ulcerative colitis. To examine long-term complications of disease in these mice, a group of 34 Beta 2mnull x IL-2null mice was monitored for 6-12 months. Development of clinical disease was assessed by wasting, general appearance, and diarrhea. Further analysis included histologic examination of the distal colon for colitis, staining of CD4+ T cells for surface activation markers, and cytoplasmic staining of CD4+ T cells for IFN-gamma and TNF-alpha. These older Beta 2mnull x IL-2null mice had activated CD4+ T cells as assessed by surface markers on flow cytometry. Cytoplasmic staining revealed IFN-gamma production, but not TNF-alpha production by CD4+ T cells. The majority of these older Beta 2mnull x IL-2null mice continued to have colitis on histology. However, they lived much longer and had less wasting in comparison to IL-2null mice. At necropsy, 11 (32%) of 34 of the Beta 2mnull x IL-2null mice had tumors in the proximal half of the colon. Histologic examination confirmed these tumors to be adenocarcinomas. These mice may be useful as a model for studying carcinogenesis in chronic colitis.

Autoimmune (Hashimoto's) thyroiditis associated with Crohn's disease

We report the occurrence of autoimmune (Hashimoto's) thyroiditis in three patients with Crohn's disease. Previously, thyroid disease has been described only in association with ulcerative colitis. We review the pertinent literature on thyroid disease in inflammatory bowel disease (IBD) and suggest that this association supports the hypothesis that autoimmunity is involved in the pathogenesis of IBD. Early diagnosis and treatment of thyroid dysfunction in patients with IBD is desirable because thyroid dysfunction worsens the symptoms and course of IBD.

Human ornithine aminotransferase complexed with L-canaline and gabaculine: structural basis for substrate recognition

BACKGROUND

Ornithine aminotransferase (OAT) is a 45 kDa pyridoxal-5'-phosphate (PLP)-dependent enzyme that catalyzes the conversion of L-ornithine and 2-oxoglutarate to glutamate-delta-semialdehyde and glutamic acid, respectively. In humans, loss of OAT function causes an accumulation of ornithine that results in gyrate atrophy of the choroid and retina, a disease that progressively leads to blindness. In an effort to learn more about the structural basis of this enzyme's function, we have determined the X-ray structures of OAT in complex with two enzyme-activated suicide substrates: L-canaline, an ornithine analog, and gabaculine, an irreversible inhibitor of several related aminotransferases.

RESULTS

The structures of human OAT bound to the inhibitors gabaculine and L-canaline were solved to 2.3 A at 110K by difference Fourier techniques. Both inhibitors coordinate similarly in the active site, binding covalently to the PLP cofactor and causing a 20 degrees rotation in the cofactor tilt relative to the ligand-free form. Aromatic-aromatic interactions occur between the bound gabaculine molecule and active-site residues Tyr85 and Phe177, whereas Tyr55 and Arg180 provide specific contacts to the alpha-amino and carboxyl groups of L-canaline.

CONCLUSIONS

The OAT-L-canaline complex structure implicates Tyr55 and Arg180 as the residues involved in coordinating with the natural substrate ornithine during normal enzyme turnover. This correlates well with two enzyme-inactivating point mutations associated with gyrate atrophy, Tyr55-->His and Arg180-->Thr. The OAT-gabaculine complex provides the first structural evidence that the potency of the inhibitor is due to energetically favourable aromatic interactions with residues in the active site. This aromatic-binding mode may be relevant to structure-based drug design efforts against other omega-aminotransferase targets, such as GABA aminotransferase.

Subspecies differentiation of Salmonella by PCR-RFLP of the ribosomal operon using universal primers

A polymerase chain reaction (PCR)-based method was developed to aid identification of bacteria to subspecies level. The method used primers that annealed to highly conserved regions of the bacterial rRNA operon, which are proposed to be universal for all bacteria. The resulting PCR products gave unique electrophoretic patterns due to restriction fragment length polymorphisms (RFLP) within the rRNA operon, allowing differentiation to the subspecies level. Six serotypes of Salmonella choleraesuis are presented to demonstrate the specificity of PCR-RFLP patterns for building an identification database. As the database continues to accumulate, the method proves to be specific and rapid for identifying bacteria based on stable genetic characteristics.

Pancreatic duct stricture length at ERCP predicts tumor size and pathological stage of pancreatic cancer

OBJECTIVE

To determine whether findings on endoscopic retrograde cholangiopancreatography (ERCP) could provide useful prognostic information in resectable pancreatic cancer.

METHODS

We retrospectively identified 18 patients with resectable pancreatic cancer (defined as no evidence of metastatic disease or vascular involvement on CT scan) who had undergone ERCP prior to an attempt at curative resection between 1991 and 1996. Common bile duct and pancreatic duct stricture lengths were measured on ERCP and compared with the size of the resected tumor. Magnification was controlled for by comparison with endoscope diameter. Stricture length was plotted against actual tumor size, and a correlation analysis was performed.

RESULTS

Pancreatic duct stricture length measured on ERCP correlated with both size (p < 0.001) and stage (p < 0.002) in resectable pancreatic cancer.

CONCLUSIONS

ERCP may provide useful preoperative prognostic as well as diagnostic information in pancreatic cancer.

Enhancement of the selectivity and antitumor efficacy of a CC-1065 analogue through immunoconjugate formation

Bis-indolyl-(seco)-1,2,9a-tetrahydrocyclopropa[c]benz[e]indol-4-on e compounds are synthetic analogues of CC-1065 that are highly cytotoxic toward a broad spectrum of tumor cell lines. One of these compounds, called DC1, was conjugated to antibodies via novel cleavable disulfide linkers. Conjugates of DC1 with murine mAbs anti-B4 and N901 directed against tumor-associated antigens CD19 and CD56, respectively, proved to be extremely potent and antigen selective in killing target cells in culture. DC1 conjugates with humanized versions of anti-B4 and N901 antibodies were also constructed and demonstrated to be as cytotoxic and selective as the respective murine antibody conjugates. The anti-B4-DC1 conjugate showed antitumor efficacy in an aggressive metastatic human B-cell lymphoma survival model in SCID mice and completely cured animals hearing large tumors. Anti-B4-DC1 was considerably more effective in this tumor model than doxorubicin, cyclophosphamide, etoposide, or vincristine at their maximum tolerated doses.

Inflammatory bowel disease therapy: an update

The armamentarium for the treatment of IBD has grown considerably within the last decade. Sulfasalazine and corticosteroids, the two cornerstones of past therapy, are now joined by the 5-ASA drugs, antibiotics, immunosuppressive agents, and newer corticosteroids. In addition, several novel therapies with promising initial results are being investigated. As the mechanisms by which these agents work are elucidated, further insight into the pathogenesis of IBD will be gained. Based on the nature and extent of disease, physicians and patients will be able to select the optimal agent or therapeutic combination for control of this enigmatic and morbid disease.

Surface composition of orthopaedic implant metals regulates cell attachment, spreading, and cytoskeletal organization of primary human osteoblasts in vitro

The nature of orthopaedic implant surfaces affects the interaction between bone and the implant. To analyze this interaction at a cellular level, this study examined the early phase of cell adhesion to implant surfaces. Using an in vitro model, the cell adhesion of primary human osteoblasts cultured on Ti6A14V (Ti), CoCrMo (CC), and tissue culture polystyrene (PS) was characterized. The osteoblasts were found to adhere in greater numbers to Ti compared with PS and CC during a 12 hour period. Other cellular characteristics related to cell adhesion, such as cell spreading, cytoskeletal organization, and focal contact formation, were also examined. Osteoblasts cultured on Ti were significantly larger, and spread better, compared with those on PS and CC. Also, the rate of cytoskeletal reorganization was enhanced on Ti. Focal contacts remained peripherally located in cells on Ti and CC as cytoskeletal reorganization proceeded. However, for cells on PS, the focal contacts quickly became dispersed along actin filaments. There was no difference between surfaces in the number of cells forming focal contacts, although the cells used a larger percentage of their membrane to attach to CC. These data suggest that osteoblast attachment to Ti is greater because cell spreading and cytoskeletal organization are enhanced. Furthermore, the mechanisms of osteoblast attachment to the underlying substrate may be significantly different between biometals and tissue culture plastic. Substrate specific information regarding the characteristics and mechanisms of cell adhesion may be helpful in the design of implants to optimize bone growth at the interface.

Anti-CD6-blocked ricin: an anti-pan T-cell immunotoxin

We report the development of a potent anti-pan T-cell immunotoxin capable of killing cells in an antigen dependent manner. The immunotoxin is composed of a high affinity anti-CD6 antibody (IgG2a, Kd = 1.3 x 10(-11) M) conjugated to blocked ricin that is a chemically modified ricin molecule wherein the lectin binding sites of the B-chain have been blocked by covalent attachment of affinity ligands. Conjugation of blocked ricin to the antibody has minimal effect on the apparent affinity of the antibody and no effect on the ribosome-inactivating activity of the ricin A-chain moiety. Anti-CD6-blocked ricin is a specific and highly toxic immunoconjugate killing the antigen-positive Molt-4 cell line with an IC37 of 4 x 10(-12) M after a 24 h exposure of cells to the immunotoxin. Nonspecific cytotoxicity of anti-CD6-blocked ricin for the antigen-negative Namalwa cell line was more than 750-fold lower with an IC37 > 3 x 10(-9) M. The cytotoxicity of anti-CD6-blocked ricin is dependent on the length of the incubation of cells with the conjugate ranging from an IC37 of 1.5 x 10(-11) M leaving a surviving fraction of Molt-4 cells of 0.03 after a 2.5 h exposure to an IC37 of 5 x 10(-13) M and leaving a surviving fraction of 3 x 10(-6) after a continuous (3 weeks) exposure. Anti-CD6-blocked ricin is also capable of killing CD6 positive cells in human peripheral blood lymphocyte populations. Systemic toxicity of anti-CD6-blocked ricin in mice is similar to the toxicity of other immunotoxins containing blocked ricin that were found to be tolerated well by patients. An application of this immunoconjugate for the prevention and treatment of graft versus host disease or tissue graft rejection is suggested.

Evaluation of the systemic toxicity and pharmacokinetics of the immunoconjugate anti-B4-blocked ricin in non-human primates. Delivered by multiple bolus injections and by continuous infusion

The systemic toxicity of an immunoconjugate of blocked ricin and the anti-CD19 monoclonal antibody, anti-B4, was studied in cynomolgus monkeys to evaluate its safety for use in humans. Anti-B4-blocked Ricin (Anti-B4-bR) is a highly cytotoxic immunoconjugate which can kill up to 5 logs of antigen positive target cells at concentrations easily achievable in blood. Subacute toxicity studies with Anti-B4-bR were performed in 20 cynomolgus monkeys and 4 rhesus monkeys, which, unlike humans, do not express the CD19 epitope recognized by the anti-B4 antibody on their B-lymphocytes. Anti-B4-bR was administered to cynomolgus monkeys by 5 daily intravenous bolus injections of 10 or 100 micrograms/kg/day, and non-conjugated blocked ricin was administered by 5 daily intravenous bolus injections of 30 micrograms/kg/day. Total doses of the conjugate of 200, 500, 1000 or 1500 micrograms/kg were also delivered to rhesus monkeys by continuous intravenous infusion over seven days. The clinical signs of toxicity, clinical pathology parameters, and gross and microscopic tissue changes associated with Anti-B4-bR were minimal to moderate where present, and primarily hepatic. In monkeys treated with 5 x 10 micrograms/kg of Anti-B4-bR, lesions were noticeable on day 7 after the start of the treatment but were less severe or absent on day 14, suggesting that the toxic effects were reversible. Clearance of the conjugate from the serum after bolus injections of Anti-B4-bR was evaluated by ELISA and demonstrated an initial t 1/2(alpha) of 1.4-2.0 h and a secondary t 1/2(beta) of about 14 h. Serum concentrations of Anti-B4-bR were about 10-20-fold lower at 24 h as compared to 1 h after each of the 5 bolus injections in monkeys. Continuous infusion of Anti-B4-bR in primates achieved plateau levels of the immunotoxin in blood for almost the entire duration of the infusion. The therapeutic utility of the Anti-B4-bR is currently being evaluated in patients with B-cell malignancies.

Anti-B4-blocked ricin immunotoxin shows therapeutic efficacy in four different SCID mouse tumor models

Anti-CD19 monoclonal antibody anti-B4 (IgG1) conjugated to the novel toxin-blocked ricin forms a potent immunotoxin, anti-B4-blocked ricin, that kills greater than 4.5 logs of CD19-positive cells in vitro after a 24-h exposure to a conjugate concentration of 5 x 10(-9) M (1.11 micrograms/ml). The efficacy of anti-B4-blocked ricin in vivo was assessed in survival models of SCID mice bearing either a human B-cell lymphoma (Namalwa), a human non-T and non-B acute lymphoblastic leukemia (Nalm-6), or a murine B-cell lymphoma transfected with the human CD19 gene (300B4). In one model, 5 x 10(7) tumor cells were injected i.p., and 1 h later the mice were treated with i.v. bolus injections of anti-B4-blocked ricin at 100 micrograms/kg/day for 5 days. Controls included similar treatment with anti-B4 antibody (72 micrograms/kg/day or 2 mg/kg/day for 5 days) alone or with the isotype-matched nonspecific immunotoxin, N901-blocked ricin (100 micrograms/kg/day). In a second model, 4 x 10(6) tumor cells were injected i.v., and 7 days later mice were treated i.v. as above. Anti-B4-blocked ricin showed efficacy by killing in vivo up to 3 logs of tumor cells, which was manifested in significant prolongation of the life of the treated animals. Only very limited or no effects were observed in animals treated with either anti-B4 antibody alone or N901-blocked ricin control conjugate. The concentration of anti-B4-blocked ricin in the blood of animals was 150 ng/ml after the first i.v. injection and about 800 ng/ml following the fifth injection of conjugate. This increase may be due to damage to the reticuloendothelial system by anti-B4-blocked ricin, since the rate of clearance of carbon from blood also decreased 5-fold after five injections as compared to the rate after only one injection. These studies indicate that anti-B4-blocked ricin has the potential to increase survival times of hosts with malignant disease.

Posterior fossa abnormalities in major depression: a controlled magnetic resonance imaging study

High-field magnetic resonance (MR) images were used to study posterior fossa morphology in 27 patients with major depression and 36 normal control subjects. Depressed patients demonstrated smaller brain stem and cerebellar vermis than controls. These differences were highly significant for the anterior cerebellar vermis and medulla. There was also a striking age-related decline in midbrain size in depressed patients as well as in controls. Our results are consistent with several lines of evidence implicating a role for the cerebellar vermis in affective disorders and, in addition, provide the first MR documentation of the differential effects of aging on posterior fossa morphology in normal subjects compared with patients with major depression.

Immunoconjugates containing novel maytansinoids: promising anticancer drugs

The potential of immunoconjugates of cytotoxic drugs for the treatment of cancer has not yet been realized owing to the difficulty of delivering therapeutic concentrations of these drugs to the target cells. In an effort to overcome this problem we have synthesized maytansinoids that have 100- to 1000-fold higher cytotoxic potency than clinically used anticancer drugs. These maytansinoids are linked to antibodies via disulfide bonds, which ensures the release of fully active drug inside the cells. The conjugates show high antigen-specific cytotoxicity for cultured human cancer cells (50% inhibiting concentration, 10 to 40 pM), low systemic toxicity in mice, and good pharmacokinetic behavior.

Molecular cloning and characterization of the RNA packaging-defective retrovirus SE21Q1b

The nonconditional RNA packaging mutant SE21Q1b contains cis- and trans-acting defects which cause cellular mRNA, rather than viral genomic RNA, to be nonspecifically packaged into SE21Q1b viral particles. Using genomic libraries of the c-SE21Q1b quail cell line, we have been able to construct a molecular clone of the SE21Q1b provirus. Upon transfection into primary quail embryo fibroblasts, the SE21Q1b molecular clone is able to recapitulate the nonspecific RNA packaging phenotype of the c-SE21Q1b cell line. The RNA packaging phenotypes displayed by several SE21Q1b/avian sarcoma-leukemia virus hybrid provirus constructs have further indicated that sequences responsible for the altered RNA packaging phenotype of SE21Q1b are localized in the left third of the SE21Q1b proviral genome. DNA sequence analysis of this region has revealed that the 5' SE21Q1b deletion has removed 179 bp from the SE21Q1b left long terminal repeat and leader regions. Several differences were detected at the carboxyl terminus of the deduced SE21Q1b nucleocapsid protein sequence in comparison with that of Rous sarcoma virus PR-C. Results of site-directed oligonucleotide mutagenesis experiments indicate, however, that the presence of these residues in the nucleocapsid protein alone is not responsible for the decreased RNA packaging specificity of SE21Q1b.

Assessment of posterior fossa structures with midsagittal MRI: the effects of age

Midsagittal magnetic resonance (MR) images of 36 normal volunteers, ranging in age from 26 to 79 years, were used to evaluate the effects of age on the size of posterior fossa structures (cerebellar vermis, midbrain, pons, medulla and fourth ventricle). Our results demonstrate a highly statistically significant age-related decline in the cross-sectional area of the midbrain (r = -.44, p less than 0.007), a less prominent decline in the area of the anterior cerebellar vermis (r = -.33, p less than 0.05) and striking intercorrelations between the dimensions of the pons, medulla and cerebellar vermis. To the best of our knowledge, this is the first MRI demonstration of midbrain atrophy during aging in normal adults.

Correlation of catabolism and antigen shedding with monoclonal antibody uptake by human colon and lung tumor xenografts

Catabolism of B6.2 and B72.3 monoclonal antibodies by human colon (LS174T) and lung (A549) tumor xenografts appears to be a variable and complex process. 125I-B72.3 and 125I-B6.2 bound to LS174T cells in vitro and localized in tumors in athymic mice. 125I-B6.2 bound to A549 cells in vitro, but did not localize in tumors. To understand these differences, tumors were grown around subcutaneously implanted micropore chambers and tumor fluid was analyzed for the presence of shed tumor antigen or functional antibody following intravenous injection. Up to two orders of magnitude lower functional B6.2 was detected in the A549 tumor fluid than in the LS174T tumor fluid. Also, A549 fluid almost totally (82-94%) inhibited binding of 125I-B6.2 to target cells in vitro due to free B6.2 antigen present in the chamber fluid. The micropore chambers utilized in this study have the potential for expanding our understanding of the way antibodies are metabolized in various types of tumors. Utility of an antibody in vivo cannot be entirely predicted from in vitro binding studies given that tumor related factors such as antibody transport, antibody catabolism and shed antigen may influence localization of antibodies in tumors. Monoclonal antibodies against nonshed antigens may prove to be more appropriate for cancer imaging and therapy.

Pituitary abnormalities in eating disorders: further evidence from MRI studies

1. The frequent occurrence of hypothalamo-pituitary dysfunction in patients with eating disorders as well as prior reports that nutritional and endocrine status influence pituitary morphology, led us to hypothesize that pituitary size and shape may be altered in patients with eating disorders. 2. Magnetic resonance imaging (MRI) does not use ionizing radiation and is currently one of the most feasible modalities available to study the pituitary gland in vivo. Using MRI, we have previously reported in a preliminary study that female patients with eating disorders had significantly smaller pituitary glands than controls. In addition MRI excluded any pituitary mass lesions. 3. In this report, we confirm our previous MRI findings and provide further evidence of pituitary abnormalities in an expanded sample of eating disorder patients. Preliminary data on pituitary volume estimates from MRI scans are provided for a subset of patients and controls.

Recombinant alpha-interferon therapy in multiple myeloma

Three patients with multiple myeloma were treated with recombinant alpha-interferon (r IFN-alpha 2b Intron AR) along with combination chemotherapy i.e. melphelan and prednisolone. In one case it was given as an initial therapy, while the other two patients had refractory and relapsing disease respectively. IFN-alpha 2b was given in the dose of 2 x 10(6) Mu/m2 by subcutaneous injection thrice in a week for six months in two patients and for three months in one patient. All three patients experienced improvement in bone pains; partial response with reduction in the paraprotein level was seen in one patient; while there was no radiological, biochemical or haematological improvement in two patients. Side effects noted were flu like syndrome in all three patients and urticaria in one patient. They were treated symptomatically and did not require cessation of interferon therapy.

Ureteric substitution with Boari bladder flap

Between 1986 and 1989, 12 patients underwent ureteric substitution with a Boari bladder flap at this Institute. The indications were ureteric injury following hysterectomy, difficult forceps delivery, difficult ureterolithotomy, ureteric strictures caused by a Dormia basket and previous ureteric surgery, tuberculosis, retroperitoneal fibrosis and a post-ureteric reimplantation fistula. There were 2 patients with a solitary kidney and 2 in acute renal failure. Double J stenting was carried out in 11 patients and the stent was removed 3 to 6 weeks post-operatively. Good results, with no morbidity or mortality, were achieved in all but 1 patient where a simple Silastic stent had migrated to the pelvis and required open surgery to remove it. We attribute our success to the tension-free anastomosis, a wide based posterior flap with preservation of its vascular supply, the use of a double J stent and vicryl suture material.

Effects of Acacia arabica and Caralluma edulis on blood glucose levels of normal and alloxan diabetic rabbits

The powdered seeds of Acacia arabica and roots of Caralluma edulis were administered in doses of 2, 3 and 4 gm/kg body-weight to normal and alloxan-diabetic rabbits. The blood glucose levels were estimated before and 2, 4, 6 and 8 hours after the administration of plant suspension. The powdered seeds of Acacia arabica exerted a significant (P less than 0.05) hypoglycemic effect in normal rabbits. The hypoglycemic effect was not significant (P greater than 0.01) in alloxan diabetic rabbits. The powdered roots of Caralluma edulis did not produce any significant (P greater than 0.01) hypoglycaemic effect in normal as well as in alloxan diabetic rabbits. The doses used did not show any acute toxicity and behavioural changes. From this study it may be concluded that the powdered seeds of Acacia arabica act by initiating the release of insulin from pancreatic beta cells of normal rabbits. Moreover, Caralluma edulis did not show any hypoglycaemic effect in normal as well as in diabetic rabbits.

Dangerousness and commitment of the mentally disordered in the United States

This article describes recent developments in mental health laws in the United States, especially as they relate to uses of the concept of "dangerousness" in the civil and criminal commitment of the mentally ill. In addition to providing a brief overview of the U.S. legal system and noting the importance of the Rule of Law, we review the historical development and current status of the relevant laws, provide some basic epidemiological statistics, and refer to some of the considerable body of extant empirical research in the field.

Correlation of vascular permeability and blood flow with monoclonal antibody uptake by human Clouser and renal cell xenografts

The specific uptake of 125I-A6H antibody by xenografts of the human renal cell carcinoma (RCC) TK177G in the athymic mouse was considerably greater than that seen for other human tumor xenografts and their associated antibodies (e.g., 125I-B6.2 uptake by the human breast carcinoma, Clouser). In addition the A6H-RCC model also demonstrated both greater localization indices and absolute amount of antibody bound than did the B6.2-Clouser model. Several physiological factors were studied to assess whether they might play a role in this greater specific uptake. Vascular volume was determined using the in situ labeling of red blood cells with 99mTc. Vascular permeability was determined by measuring the amount of 125I-labeled bovine serum albumin and 131I-labeled nonspecific IgG1 (anti-horseradish peroxidase) extravasated out of the tumor vasculature during 1 hr. Relative blood flow to the tumor was determined using the 86Rb method. Blood flow and vascular permeability were found to be significantly greater in the RCC tumor xenografts than in Clouser tumors. Differences in vascular permeability were especially dramatic, showing the vasculature of the RCC xenograft was twice as permeable as that of the Clouser tumor. Animals bearing either RCC or Clouser xenografts were injected with a monoclonal antibody to human major histocompatibility complexes (125I-labeled anti-human histocompatibility complex A, B, C). Tumor uptake of 125I-labeled anti-human histocompatibility complex A, B, C was found to be 5 times greater in RCC than Clouser xenografts. These results, therefore, suggest that the differences seen in the physiological factors studied can account for some of the greater specific 125I-A6H uptake by the RCC tumor than 125I-B6.2 uptake by the Clouser xenograft.

A technique for simultaneous antikinetochore immunofluorescence staining and Q-banding in chromosomes from human lymphocytes

Antikinetochore immunofluorescence staining has been used in several studies to determine whether a second kinetochore is present, active, or both, in multicentric chromosomes. All of these studies have used tissue culture cells, and contended with the problem of obtaining well spread, banded metaphase chromosomes without affecting the kinetochore staining. We have adapted hypotonic, centrifugation and chromosome staining techniques to obtain simultaneous Q-banding and bright kinetochore staining of chromosomes from human lymphocytes.

Lymphoscintigraphy of human colorectal carcinoma metastases in athymic mice by use of radioiodinated B72.3 monoclonal antibody

The potential of radioiodinated monoclonal antibody B72.3 for lymphoscintigraphy was evaluated, using suitable animal models of a human colorectal carcinoma. LS174T xenografts were grown at various sites in beta-estradiol-pretreated athymic mice, and the development of metastases in different organs was assessed histologically. After iv inoculation of the mice, 66% of the animals developed "metastases" to the axillary lymph nodes. Of these mice, 100% also developed multiple tumors on their backs and 79% had lung micrometastases. Livers, kidneys, and spleens showed no evidence of tumor growth. In 33% of the mice in which primary LS174T tumors had been removed from the hindfoot pad, metastases to the popliteal lymph nodes were observed 3 1/2 weeks after tumor implantation. BALB/c (nu/nu) female mice bearing axillary and popliteal lymph node metastases were used to test the potential of radiolabeled B72.3 antibody (an IgG1) as a lymphoscintigraphic agent. A monoclonal antibody against horseradish peroxidase (also an IgG1), which did not bind LS174T tumor cells in vitro, served as a control. Both normal and tumor-bearing axillary and popliteal lymph nodes imaged up to 6 hours after the sc injection of 20-40 mu Ci of 125I-labeled B72.3 into either the forefoot or hindfoot pads. The localization index (L.I.) (specific/nonspecific antibody in tumor divided by specific/nonspecific antibody in blood) for LS174T tumors in lymph nodes was approximately 1 during the first 6 hours after antibody injection, thus indicating no specific antibody accumulation. Twenty-four hours and later after sc injection, images of nodal metastases (14-477 mg) and specific antibody accumulations were observed. At these times the L.I.'s ranged 1.5-3.5. Tumor-negative nodes did not image at 24 hours after injection of 125I-labeled B72.3. The L.I.'s of the normal nodes and of other tissues from these mice were about 1.0 at 24 hours, indicating no specific antibody accumulation. Autoradiographic analysis of lymph nodes containing LS174T tumor showed heterogeneous antibody distribution of B72.3 within tumor sections with heavy patches of antibody accumulation in mucin globules. In lymph nodes the normal lymphocytes adjacent to the LS174T tumor cells showed no antibody accumulation. The lack of specific, early antibody accumulation by LS174T tumor-bearing nodes in mice suggests that B72.3 does not accumulate in nodal metastases to the degree necessary to consider it a potential agent for use in lymphoscintigraphy.

Site-related differences in the localization of the monoclonal antibody OX7 in SL2 and SL1 lymphomas

The uptake of a monoclonal antibody (OX7) by murine lymphomas (SL1, SL2) growing in two sites in the mouse were compared. SL2 tumors grown in the subrenal site showed greater specific antibody uptake than did the same tumor grown in the subcutaneous site. Major differences in membrane bound antibody, in vitro antibody binding patterns, and gamma scintillation camera imaging were also observed between the two sites. These differences may be due to the greater blood flow measured in tumors growing in the subrenal capsule than those growing at the subcutaneous site. The differences observed in antibody uptake of the same tumor growing in two different sites raises questions concerning the choice of animal model systems that can be used to predict clinical utility.

Radioimmunodetection of small human tumor xenografts in spleen of athymic mice by monoclonal antibodies

The ability of radiolabeled monoclonal antibodies to accumulate in and image small human tumors growing in the spleen of athymic mice was assessed. The antibodies B6.2 and B72.3, which reacted against human breast (Clouser) and colon (LS174T) tumor cells in vitro and in vivo, respectively, and the isotype matched anti-horseradish peroxidase antibody which did not bind to these tumors were used in pharmacokinetic and imaging experiments. Human melanoma cells and tumors (A375) which did not react with any of the three antibodies were used as additional controls. Radioiodinated "tumor specific" and non-specific antibodies were injected i.v. into athymic mice bearing intrasplenic tumors and the mice were sacrificed at various times to assess the specificity of uptake of these antibodies into tumor and normal host tissues. The accumulation of B6.2 in the Clouser tumor was maximal at 24 h as indicated by a localization index (specific/nonspecific antibody in tumor divided by the same ratio in blood) of about 4.0. The uptake of B72.3 in LS174T tumor increased with time with a localization index of about 12.0 observed at 50 h post-antibody injection. Localization indices for the control A375 tumor and for all normal mouse tissues, including the uninvolved portion of the tumor bearing spleen, were between 0.8 and 1.0, thus indicating no specific antibody accumulation. The relative blood flows of the Clouser and A375 tumors, as determined by the 86RbCl method, were similar. The results suggested that immunospecificity was a major factor in antibody localization in vivo. Specific images of approximately 100-mg Clouser tumors with radiolabeled B6.2 and of LS174T tumor with radiolabeled B72.3 were seen by 24 h after antibody injection. Images of smaller (about 20 mg) LS174T tumors were seen by 48 h following B72.3 injection. The control antibody, anti-horseradish peroxidase, did not image either Clouser or LS174T tumor. Also the control tumor was not imaged with any of the three antibodies tested. The data generated with this novel animal model support the concept of using radiolabeled monoclonal antibodies for detecting and possibly treating small metastatic visceral tumors in cancer patients.

Vascular volume and permeability of human and murine tumors grown in athymic mice

99mTc-labeled red blood cells have been used to measure tumor vascular volume (VV). When combined with the use of 125I-labeled bovine serum albumin [( 125I]BSA) and 131I-labeled IgGs this method also provides the rapid simultaneous determination of tumor vascular permeability (VP). Using this technique the VV and VP of a human (Clouser) and a murine tumor (SL2) grown in athymic mice were determined. The relative VV were Clouser = SL2 greater than or equal to skin greater than muscle. The relative VP of BSA and IgG were Clouser greater than SL2 = skin greater than muscle. These results may explain the differences observed in the accumulation of monoclonal antibodies in human and murine tumors grown in the athymic mouse.

Enhanced thermal response of a rat sarcoma by Corynebacterium parvum

Corynebacterium parvum was investigated in the response of rat Mc7 sarcoma to local waterbath hyperthermia. Heat treatment of 1-1.5 cm3 foot tumors at 43 degrees C for 2 h resulted in complete regression of 71% of the tumors. The Mc7 cure was reduced to 31% when the tumors were heated at 43 degrees C for 1.5 h. C. parvum (700 micrograms, i.v.) when given 1-3 days before tumor heating at 43 degrees C for 1.5 h increased the host phagocytic activity, and the tumor regression from 31% to 65% (P less than 0.05). C. parvum by itself had no curative effect on the tumor, and it did not enhance the thermal response of normal rat foot to hyperthermia. These findings suggest that host response to tumor heating may be 'non-specific' in nature involving phagocytes of the reticulo-endothelial system.

The imaging of small experimental murine tumors grown in the subrenal capsule using monoclonal antibodies

The ability of a "tumor-specific', monoclonal antibody (OX7) and a subclass-matched, non-specific, control antibody (anti HRP) to localize in and image small (20-60 mg) murine lymphomas growing in the subrenal capsule of mice was tested. Due to the small tumor size, and its visceral location, the subrenal site of tumor growth represents a model of metastases which may be more clinically relevant to human cancer. The in vivo and in vitro quantitative data (as well as the gamma camera images) support the feasibility of the concept of using monoclonal antibodies for metastatic tumor detection and treatment.

Continuous noninvasive monitoring of pH and temperature in rat Walker 256 carcinoma during normoglycemia and hyperglycemia

The extracellular pH and temperature of Walker 256 carcinoma and of normal subcutaneous tissue were measured continuously in unanesthetized female Sprague-Dawley rats for up to 20 hours following glucose or galactose administration. The pH was monitored with flexible glass electrodes contained in micropore chambers implanted in the flank of a rat. Temperature was measured with miniature thermistor probes incorporated in the tumor or in subcutaneous tissue. The pH in the untreated Walker 256 carcinoma decreased linearly from approximately 7.3 to 6.2 with increasing tumor mass up to 50 g. Administration of glucose (6 g/kg body wt, ip) in tumor-bearing rats increased glucose concentrations in blood and tumor, as well as lactic acid concentration in tumor, and had no significant effect on lactic acid concentration in blood. Plasma volume was not affected by either glucose or galactose loading as compared to that in rats given saline alone. However, the blood viscosity increased by up to 30% within 30 minutes after galactose injection, but not after glucose injection, and this significant difference in viscosities persisted for approximately 6 hours after glucose and galactose injections. In small tumors (less than 10 g), a decrease of up to 1 pH unit was observed within 6 hours after glucose administration, and the return of pH to pretreatment values began about 10 hours after glucose injection. Response of large ulcerated tumors (greater than 20 g) was not as uniform; the pH decreased by about 0.5 to 1 pH unit for only a brief period. After galactose injection, pH in some tumors remained unchanged, whereas in others an average decrease of about 0.2 pH units was observed. The pH in normal tissue was not affected by glucose or galactose administration. Both glucose and galactose decreased tumor temperature by about 7 degrees C.

Enhanced metastasis formation by combined hyperthermia and hyperglycemia in rats bearing Walker 256 carcinosarcoma

Hyperglycemia has been shown to decrease tumor pH and blood flow rates, consequently this could increase the sensitivity of tumor to hyperthermia. Combined waterbath hyperthermia (43 degrees C/2 h) and hyperglycemia (6 g/kg, i.p.) was investigated on survival of rats bearing a metastasizing form of Walker 256 carcinosarcoma. Hyperthermia alone increased the survival rate of animals from 19% to 42%. Hyperglycemia promoted more uniform tumor heating in the foot. However, combined hyperthermia and hyperglycemia led to a significant decrease in the survival rate of animals (10%; P less than 0.001), and most rats died with widespread metastasis in lymph nodes, lungs and kidneys. These findings do not support the postulate that hyperglycemia leads to sensitization of tumor destruction by hyperthermia.

Comparison of DMSO and glycerol as cryoprotectants for ascites tumor cells

Mouse Ehrlich ascites and rat D23 ascites tumors were stored in liquid nitrogen under identical conditions for up to 3 years. Cell viability (trypan blue exclusion) and transplantability of both tumors in animals remained virtually unaffected if preserved in 10% DMSO containing medium, whereas, cells preserved in 10% glycerol failed to produce lethal tumors in rodents.

Hyperthermia: the immune response and tumor metastasis

Evidence is circumstantial that in animals and, to some extent, in man, an antitumor immune response may be generated after curative hyperthermia that leads to disappearance of metastases (abscopal response) and the acquisition of host immunity. In rodents, tumor regression after heating does not occur in immunosuppressed hosts, and the tumor cure rate is significantly reduced by inhibition of macrophage activity with silica; cured immune rats succumb to tumor inoculation when immunosuppressed. Quantitative data for cellular and humoral immunocompetence in these situations exist for only a few tumor types, and the bulk of evidence indicates that host response following tumor heating is nonspecific in type, with a major macrophage component. Little is distinctive about the regression of heated tumors, i.e., an abscopal response can follow treatment of tumors by excision or hypothermia. In man, an immune response is seldom evoked by the heating of the common solid tumors. Whole-body heating in animals can cause immunosuppression, probably from a direct damaging effect on lymphoid tissue, and enhanced metastatic spread may follow in the tumor-bearing host, but this has not been proved in man. The differences in response of tumors to heat in animals and man may be due to variations in tumor immunogenicity and host tolerance to heat.

Antigenic differences between a primary hamster lymphosarcoma and its liver metastases

An antiserum was raised in rabbits against a primary metastasizing lymphosarcoma (ML) of the hamster. This was made tumor-specific by absorption with normal hamster tissue extracts. Immunoglobulin-G was prepared and tested for its cytotoxicity towards cells derived from the primary tumor and its liver metastases. The ML-specific IgG was found to be 2--5 times more cytotoxic for cells derived from the primary tumor compared to cells obtained from liver metastases.

Effects of hyperthermia and hyperglycemia on the metastases formation and on survival of rat bearing W256 carcinosarcoma

Hyperthermia (temperatures less than 42 degrees C) is widely used in the treatment of cancer. Current thrust in this field is directed towards using agents which can potentiate the effects of hyperthermia. Combined local hyperthermia (43 degrees C/2 hours) and hyperglycemia (6g glucose/kg body weight; mean blood glucose levels of 500 mg%) was investigated for treating a metastasizing form of a rat W256 carcinosarcoma. Glucose loading of the tumor-bearing rats rendered the foot tumors physically more easy to heat (due to inhibition of tumor blood flow), but combined hyperthermia and hyperglycemia lead to a decrease in survival rate (13% compared to 41% with heat alone), most animals died with widespread metastases in lymph nodes, lungs and kidneys. The data does not support the postulate that hyperglycemia leads to sensitization of tumor destruction by hyperthermia. We suggest that Corynebacterium parvum, a non-specific immunostimulant, should be thoroughly investigated as a potentiator of hyperthermia.

General model for dissolution rates of n-component, nondisintegrating spheres

The dissolution rates of compressed spheres consisting of two and three components were measured. A general model for dissolution rates of n-component, nondisintegrating spheres is discussed. Experimental cases are presented to support the model for two- and three-component spheres, two-component interacting spheres, and three-component spheres containing two components that complex.

Participation of the immune system in regression of a rat Mc7 sarcoma by hyperthermia

Participation of the host immune response in eradication of tumor by hyperthermia has been suspected for a long time. The effect of local tumor heating on the immunocompetence of rats bearing Mc7 sarcoma was studied. Following heat treatment of 1- to 1.5-ml foot tumors at 43 degrees for 2 hr, regression of primary tumors resulted in host cure (15 of 21; 71%), and this was accompanied by an increased skin response to both 3 M KCl extract of Mc7 and dinitrochlorobenzene as well as in elevation of antibody to bovine serum albumin. Animals that were cured by hyperthermia showed no sign of metastatic tumor in lymph nodes and lungs; most control animals at the time of heat treatment had secondary tumor deposits in lymph nodes and lungs. Tumor regression after curative heating did not occur in rats (0 to 10) treated by whole-body X-rays (150 R; 3 times) plus cortisone acetate (60 mg/kg; 4 times; s.c.), and the tumor cure rate was reduced (9 of 21; 43%) by blocking macrophage activity with silica (1 g/kg; i.v. and i.p.). Also, these rats (43%) succumbed to tumor challenge with 2.5 x 10(6) Mc7 cells; 50% of the heat-cured animals not given silica consistently rejected this challenge dose. The results imply that immunostimulation comprising mainly T-cells and macrophages plays a major part in tumor regression by hyperthermia.