Autoantibodies against platelet glycoprotein Ib in patients with chronic immune thrombocytopenic purpura

The present studies provide direct evidence that some patients with chronic immune thrombocytopenic purpura (ITP) have autoantibodies reactive with platelet glycoprotein Ib ( GPIb ). Microtiter wells coated with a monoclonal antibody that recognized GPIb were reacted with either platelet extract or a control cell extract. After washing and incubating with test plasma, well-bound IgG was quantitated using radioactive anti-IgG. When compared to plasma from normal subjects, plasma from 3 of 106 patients with chronic ITP had significantly increased quantities of IgG bound to microtiter wells reacted with platelet extracts. Negative results were obtained with the remaining 103 patients with chronic ITP and 59 patients with a variety of other platelet disorders. Plasma from two of the three positive patients precipitated a protein from 125I-surface-labeled platelet extract with a molecular weight similar to GPlb . One of the three patients with anti- GPlb antibody also had demonstrable autoantibodies to the platelet glycoprotein llb / llla complex.

Induction of forestomach hyperplasia by crude butylated hydroxyanisole, a mixture of 3-tert and 2-tert isomers, in Syrian golden hamsters is due to 3-tert-butylated hydroxyanisole

Male Syrian golden hamsters were given 1.0% 2-tert- or 3-tert-butylated hydroxyanisole (BHA) or crude BHA for 1 to 4 weeks. The incidence of severe hyperplasia induced in the forestomach was high in the hamsters given 3-tert-BHA or crude BHA for 2 weeks or more, but was almost at the control level in those given 2-tert-BHA. Thus, the 3-tert isomer would appear to be responsible for the tumorigenicity of crude BHA.

Dose-related induction of lung, thyroid and kidney tumors by N-bis(2-hydroxypropyl)nitrosamine given orally to F344 rats

The organotropic effect of orally administered N-bis(2-hydroxypropyl)nitrosamine (DHPN) in male F344 rats was studied with respect to total dosage and length of observation period. DHPN was given at 5 dosages, a single intragastric intubation of 800 mg/kg body weight, or administration as a 0.2% solution in the drinking water for 4, 7, 14 or 21 days. Animals were killed at weeks 32, 40 and 48. Tumors were induced in the lung, thyroid, kidney and urinary bladder. High tumor incidence was demonstrated in the lung and thyroid. Dose-related increases in overall tumor incidences in these 4 organs were clearly shown but time-related increases at the 3 sacrifice time points were not clear. Histologically, the tumors were adenoma and adenocarcinoma of the lung and thyroid, renal cell tumor, nephroblastoma and transitional cell tumor of the kidney, and transitional cell papilloma of the urinary bladder.

Promotion by ascorbic acid, sodium erythorbate and ethoxyquin of neoplastic lesions in rats initiated with N-butyl-N-(4-hydroxybutyl) nitrosamine

The promoting effects of ascorbic acid, sodium erythorbate and ethoxyquin on two-stage urinary bladder carcinogenesis in F344 rats initiated with N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) at a dose of 0.05% in the drinking water were examined. Administration of 5% sodium erythorbate in the diet significantly increased the incidences of preneoplastic lesions, papilloma and cancer of the urinary bladder, whereas administration of 5% ascorbic acid in the diet did not. Administration of 0.8% ethoxyquin also increased the incidence of neoplastic lesions. Administrations of 5% sodium L-ascorbate and 5% sodium erythorbate caused increases in the pH, the sodium content and crystals of MgNH4PO4 in the urine. These results show that sodium erythorbate and ethoxyquin promote urinary bladder carcinogenesis, while ascorbic acid does not.

Surface expression of human myeloma cells: an analysis using a panel of monoclonal antibodies

Neoplastic cells of 18 patients with multiple myeloma were studied using a panel of 6 monoclonal antibodies to B cells and monospecific antisera against the light chain types of immunoglobulin. OKT10 bound to the myeloma cells of all the patients, although only a small percentage of the cells reacted in 3 instances. Monoclonal sIg was present in 5 patients. HLA-DR antigen detected with OKIa-1 was found in 5 patients. B1 bound to a small percentage of the myeloma cells only in 2 patients who had received treatment. The B1+ cells were always sIg+. In 3 patients, BA-2 reacted with the myeloma cells. BA-1 and BA-3 invariably did not react with the cells. Myeloma cells with B cell markers were found more frequently in treated patients than in untreated patients. The RPMI8226 line was also studied and found to react with OKT10 and BA-2. The results of this study show the presence of phenotypic variety in myeloma cells.

Long-term toxicity and carcinogenicity test of ammonia-process caramel colouring given to B6C3F1 mice in the drinking-water

Caramel colouring (ammonia process) was given at levels of 0 (control), 1.25 and 5.0% in the drinking-water to groups of 50 male and 50 female mice for 96 wk, and then all all the animals were maintained without caramel for a further 8 wk. Males given 5.0% caramel showed increased cumulative mortality from wk 100 to the end of the experiment. The white blood cell count in treated males was significantly elevated in a dose-related manner. However, these changes were not considered to be biologically significant. There were no treatment-related effects on clinical signs, body or organ weights, results of urine analyses, or histological features. Therefore, this study did not demonstrate any carcinogenic effect of caramel on mice at levels of up to 5.0% in the drinking-water.

Promoting effect of sodium o-phenylphenate and o-phenylphenol on two-stage urinary bladder carcinogenesis in rats

The effects of sodium o-phenylphenate (OPP-Na) and o-phenylphenol (OPP) on 2-stage urinary bladder carcinogenesis in F344 rats initiated with N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) at levels of 0.01 or 0.05% in drinking water were investigated. Administration of 2.0% OPP-Na in the diet significantly increased both the incidence and the number per 10 cm of basement membrane of preneoplastic lesions (papillary or nodular hyperplasia; PN hyperplasia) of the urinary bladder in rats pretreated with 0.01% BBN, and also those of papilloma and cancer of the urinary bladder in the group pretreated with 0.05% BBN. Moreover, treatment with 2.0% OPP-Na, without prior BBN initiation, induced PN hyperplasia, papilloma and cancer. In contrast, OPP appeared to produce only a slight increase in the incidence of urinary bladder lesions following BBN, and its effect was not statistically significant. It also did not induce tumors of the urinary bladder. These results provide evidence that OPP-Na has promoting activity toward the urinary bladder while OPP does not. Moreover, the possibility that OPP-Na may be a complete carcinogen in the rat urinary bladder deserves consideration.

Two-dimensional gel electrophoretic analysis of the HindIII 1.8-kb repetitive-sequence family in the human genome

The structure and organization of a human repetitive DNA family containing the HindIII 1.8-kb repetitive sequence were studied, using two-dimensional (2D) gel electrophoresis. The HindIII 1.8-kb sequence proved to be part of a repetitive sequence about 5 kb long and interspersed on the genome. The long repetitive sequence family contained several subgroups, as based on polymorphism of the restriction site. Recombinant phages containing the long repetitive sequence were isolated from the human genomic DNA library. Heteroduplex and restriction analysis showed that the structure of the repetitive sequence carried by the phages was close to that expected from 2D gel electrophoretic analysis. The 2D gel electrophoretic analysis was shown to be a reliable and useful approach for surveying and mass analysis of repetitive sequence families.

Effect of dibutyltin dichloride on incidence of pancreatic adenocarcinoma induced in hamsters by a single dose of N-nitrosobis(2-oxopropyl)amine

The effects of timing of a single intragastric application of dibutyltin dichloride, at a dosage of 30 mg/kg body wt, on N-nitrosobis(2-oxopropyl)amine (BOP)-induced pancreatic carcinomas have been studied in female Syrian golden hamsters. Dibutyltin dichloride, which has been shown to produce selected bile duct injury, was administered either 1 week before or 1 week after a single injection of BOP (20 mg/kg body wt). Control hamsters were injected with BOP alone or were given dibutyltin dichloride alone. The incidence of ductal adenocarcinomas strikingly decreased in hamsters when dibutyltin dichloride was ingested after BOP treatment, but remained unaffected when dibutyltin dichloride was given before carcinogen treatment. Two cases of sarcoma were observed in the group treated with dibutyltin dichloride before BOP injection. The incidence of insulomas, which were considered as spontaneous tumors, was not influenced by dibutyltin dichloride. These results showed that intragastric application of dibutyltin dichloride after BOP treatment significantly reduced the induction of pancreatic cancer. These findings do not support speculations based on epidemiologic studies as to a promoting effect of cholestasis.

Alteration of T cell subsets and immunoglobulin synthesis in vitro during high dose gamma-globulin therapy in patients with idiopathic thrombocytopenic purpura

T cell subsets of peripheral lymphocytes were studied using monoclonal antibodies (OKT3, OKT4, OKT8) and immunoglobulin (IgG, IgM, IgA) synthesis in vitro by peripheral mononuclear cells stimulated with pokeweed mitogen was studied in adult patients with idiopathic thrombocytopenic purpura before and after high-dose intravenous intact gamma(gamma-)globulin therapy, at a daily dose of 0.4g/kg body weight for 5 consecutive days. A transient increase in platelet count which reached a peak on the 1st to 2nd days after the end of the therapy was observed in four of five patients. Immunoglobulin synthesis in vitro was suppressed remarkably following therapy in all cases: the mean reduction of IgG, IgM and IgA was 78, 66 and 48%, respectively. Titres of various autoantibodies, TGHA, MCHA, ANF and anti-DNA antibody, also decreased following therapy. In correspondence to this, phenotypic analysis in T cell subsets showed a decrease of OKT4+:OKT8+ ratio following therapy, without a change in the proportion of OKT3+ cells. These data indicate that the intravenous gamma-globulin preparations suppressed synthesis of antibodies non-specifically and caused a relative increase of OKT8+ suppressor T cells.

Organ-specific promoting effect of phenobarbital and saccharin in induction of thyroid, liver, and urinary bladder tumors in rats after initiation with N-nitrosomethylurea

Tumor-promoting effects of phenobarbital (PB) and sodium saccharin (SS) were tested in rats pretreated with N-nitrosomethylurea (NMU) with special reference to the site of their action. Male F344 rats were initially given injections of NMU (20 mg/kg i.p.) twice a week for 4 weeks, then given basal diet containing 0.05% PB or 5% SS for the next 32 weeks, and then killed. Appropriate control studies were also done. Histological examination of whole organs of the rats showed that PB promoted thyroid carcinogenesis whereas SS did not. A significant increase in the incidences of total tumors as well as papillary adenocarcinoma of the thyroid was observed in the group given PB after NMU (p less than 0.001). The incidence of papillary adenoma with or without papillary adenocarcinomas was also high in the NMU-PB-treated group. The organ-specific promoting effect of PB in the induction of preneoplastic lesions, as demonstrated by development of gamma-glutamyl transpeptidase-positive foci in the liver and of SS in papillary or nodular hyperplasia in the urinary bladder, as reported previously, was also confirmed. The incidences of papillomas in the forestomach were similar in groups treated with NMU-PB, NMU-SS, or NMU alone. The results indicate that PB is a tumor promoter in the liver and thyroid and that SS is a tumor promoter in the urinary bladder of rats.

A human B lymphocyte antigen (P-76) shared by B-cell chronic lymphocytic leukemia cells and hairy cell leukemia cells

A membrane antigen with an apparent specificity to B lymphocytes was detected with immunochemical techniques and its properties were analyzed. Anti-B-CLL serum was raised in a rabbit by immunization with B-cell chronic lymphocytic leukemia (B-CLL) cells. This anti-B-CLL serum was absorbed with erythrocytes, liver homogenate and insolubilized immunoglobulins. After further absorption with T-CLL cells, chronic myelocytic leukemia (CML) cells and acute myelocytic leukemia (AML) cells, the anti-B-CLL serum still reacted with peripheral blood B lymphocytes, B-CLL cells and hairy cell leukemia (HCL) cells. In contrast, no reactivity was seen with peripheral blood T lymphocyte or monocytes, or leukemia cells of non-B cell origin. An immunoprecipitation of radiolabeled cell surface proteins was attempted using the anti-B-CLL serum in the presence of Staphylococcus Aureus Cowan 1 (SaCl), and the precipitates were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). A membrane antigen with an apparent molecular weight of 76,000 daltons (P-76) was immunoprecipitated with the anti-B-CLL serum from the lysates of normal B lymphocyte, B-CLL cells and HCL cells. The antigen (P-76) is not composed of disulfide-linked subunits and has no structural relationship with HLA-DR (Ia-like) antigens or other known antigens. These results suggest that this antigen is B-lymphocyte specific, and favour the B-lymphocyte nature of HCL cells.

Different dose-response relationships in the induction of different types of colonic tumors in Wistar rats by 1,2-dimethylhydrazine

Four groups of 21 male Wistar rats were given weekly subcutaneous injections of 1,2-dimethylhydrazine at a dose of 20 mg/kg body weight for 2, 4, 6 and 8 weeks, respectively, and 7 animals of each group were killed in weeks 24, 32 and 40. This treatment induced a clear dose-related increase in the total number of colonic carcinomas. The number of tubular adenocarcinomas, which were mostly located in the descending colon, was clearly dose-related, whereas the number of signet ring cell carcinomas, which developed in the ascending colon, was apparently dose-independent.

Heavy chain loss after treatment with Melphalan in a patient with "nonsecretory" myeloma

A case of "nonsecretory" myeloma is described. The patient had typical osteolytic lesions and marked infiltration of myeloma cells in the bone marrow, and plasma cell leukemia. A good partial remission was obtained with Melphalan, but the patient relapsed and died one year later. Immunofluorescent and immunoelectroscopic studies on the myeloma cells demonstrated the presence of cytoplasmic gamma-and kappa-chains at the initial stage and of only kappa-chains at a relapse. The electron microscopic method for polysome analysis indicated that both L-and H-chains were synthesized on membrane-bound polysomes initially, but the ability to produce H-chain was missing at the relapse.

In vitro platelet phagocytosis in idiopathic thrombocytopenic purpura

In vitro phagocytosis of platelets from patients with idiopathic thrombocytopenic purpura (ITP) (direct assay) and phagocytosis of normal platelets sensitized with patient serum (indirect assay), using normal peripheral blood leukocytes, were studied to find out whether the degree of phagocytosis reflects the severity of ITP. Phagocytosis was measured by the uptake of 51Cr-labeled platelets. Among patients whose platelet count was below 10 X 10(4)/microliters, 92% showed an increase in the phagocytosis ratio by the direct assay and 67% by the indirect assay. There was a highly significant inverse correlation between the direct phagocytosis ratio and the platelet count (p less than 0.001), but not between the indirect phagocytosis ratio and the platelet count. The amount of platelet-associated IgG (PAIgG) measured in patients whose platelets were used for the direct assay also showed an inverse correlation with the platelet count (p less than 0.05). Vincristine administration provoked a reduction in the direct phagocytosis ratio and PAIgG value. We propose that both the direct assay and PAIgG measurement reflect the severity of ITP, and PAIgG might be responsible for platelet phagocytosis.

High-dose gammaglobulin therapy for idiopathic thrombocytopenic purpura in adults

High-dose gammaglobulin therapy for patients with idiopathic thrombocytopenic purpura (ITP), introduced by Imbach et al., was applied to 5 adults with chronic refractory ITP to investigate the mechanism of the increase in platelet counts. In 4 of the 5 cases, transient increase in platelet count was observed. Platelet-associated IgG was decreased in 3 cases, increased in 1 case and unchanged in 1 case after treatment. In 4 cases having a variety of autoantibodies, the antibody titers decreased after treatment. No significant changes in antiplatelet antibody titers in serum, or in circulating immune complexes were observed during or after these treatments. No side effects were noted in any of the cases. These results indicate that the treatment is suitable for the treatment of patients prior to surgery and of patients at high risk of intense bleeding and death. It can be reasonably assumed that the increased platelet count is mainly due to a defective removal of antibody-coated platelets.

[Clinical use of amikacin sulfate in the treatment of bacterial infections and prevention of postoperative infections in the orthopedic field]

Investigation was made on the effectiveness and safety of amikacin (AMK) in the treatment of bacterial infections and prevention of postoperative infections in the orthopedic field. The details of 14 infectious patients treated with AMK were as follows; osteomyelitis in 5, purulent arthritis in 3, decubitius in 3, cystitis in 2 and purulent peritonitis in 1. For prevention of postoperative infections, AMK was administered to 9 patients. In 14 infectious patients, clinical response was excellent in 2, good in 11 and poor in 1, while in 9 postoperative patients clinical response was excellent or good in all of them. As side effects, a slight rise of the GOT and GPT levels was observed in 1 but normalized by discontinuation of the medication. In the aspects of effectiveness and safety, AMK may be considered to be a useful available antibiotic in the orthopedic field.

Lack of carcinogenicity of butylated hydroxytoluene on long-term administration to B6C3F1 mice

Groups of approximately 50 male and 50 female B6C3F1 mice were given butylated hydroxytoluene (BHT) at concentrations of 200, 1000 or 5000 ppm in their diet for 96 wk followed by a basal diet for 8 wk and were then killed. Similar groups of male and female controls were given basal diet throughout the 104 wk. Females given 1000 or 5000 ppm BHT and males given 5000 ppm showed reduced weight gain. Neither survival rates nor food consumption differed between experimental and control groups. No significant changes attributable to BHT treatment were found in the haematological examinations or serum and urine analyses. Tumours were found in many organs, especially the lungs, liver, lymph nodes and spleen, in both the experimental and control groups, but none were related to BHT treatment. Thus this experiment provided no evidence of BHT carcinogenicity in mice.

Vascular tumors of the spleen and other neoplasms induced in Syrian golden hamsters by 1-propyl-1-nitrosourea

Continuous administration of either 400 ppm or 100 ppm 1-propyl-1-nitrosourea (PNU) in drinking water to Syrian golden hamsters, from 11 weeks of age, induced tumors of the spleen, forestomach, duodenum, and vagina. The tumor incidences in the spleen were 33 of the 36 males (91.7%) and 34 of the 37 females (91.9%) in the 400 ppm group and 32 of the 40 males (80%) and 26 of the 34 females (76.5%) in the 100 ppm group. In addition, tumors were induced in the forestomach and duodenum of both sexes and in the vagina in females. Histologically, the tumors were classified as hemangioendotheliomas of the spleen, squamous cell papillomas and carcinomas of the forestomach, adenocarcinomas of the duodenum, and squamous cell papillomas and carcinomas of the vagina. Compared to results previously reported in rats, the present results reveal a remarkable species difference in the organ specificity of PNU.

Quantitative analysis of initiating and promoting activities of five mycotoxins in liver carcinogenesis in rats

The initiating and promoting activities of several mycotoxins were investigated in F344 male rats. N-2-Fluorenylacetamide (2-FAA) was used as an initiator or a promoter and citrinin, ochratoxin A, sterigmatocystin, (+)rugulosin or patulin was administered at a fixed dose for the same period in the initiation stage or the promotion stage. Partial hepatectomy and administration of carbon tetrachloride (CCl4) were examined to increase the induction of hyperplastic nodules. Ochratoxin A, sterigmatocystin and (+)rugulosin administered in either the initiating or the promoting stage significantly increased the induction of hyperplastic nodules. Citrinin and patulin administered in the initiating stage significantly increased the induction of hyperplastic nodules, but were not effective when administered during the promoting stage. The theoretical classification of the mycotoxins examined is discussed.

Neural and humoral factors influence gastric receptive relaxation in dogs

To clarify the neural and humoral factors which control gastric receptive relaxation, the effects of various types of vagotomy or splanchnicotomy on receptive relaxation of the canine innervated corpus pouch were investigated. The influence of gastrin, histamine H1-receptor antagonist, and anti-histamine releasing agents on receptive relaxation were also examined. Selective proximal vagotomy or splanchnicotomy resulted in a slight disturbance in receptive relaxation. Truncal vagotomy produced a marked disturbance in receptive relaxation. Administration of tetragastrin potently inhibited receptive relaxation, however, recovery occurred by injecting a histamine H1-receptor antagonist. Increased serum gastrin induced by perfusion of the antrum with liver extract solution disturbed receptive relaxation and this response was inhibited by pretreatment with transamine, an inhibitor of histamine release from histamine secreting cells. These results indicate that receptive relaxation in the canine stomach is controlled not only by vagal and splanchnic nerves, but also by gastrin and histamine.

Carcinogenicity of phenacetin: long-term feeding study in B6c3f1 mice

Groups of 52 B6C3F1 mice of each sex were maintained on a diet containing 1.25 or 0.6% phenacetin for 96 weeks and then fed a basal diet for 8 weeks. Control groups consisted of 50 mice of each sex and were fed a basal diet for 104 weeks. All animals were killed at the end of the experiment and all organs were examined histopathologically. Mice that died during the experiment were also autopsied and those that survived for more than 57 weeks, when the first tumor was observed, were also included in the effective number of mice. Tumors were found in the kidney, liver, lung, skin, hematopoietic system (leukemia or lymphoma) and occasionally in some other organs. The dose-related induction of renal cell tumors in the male mice fed phenacetin was clearly demonstrated in this experiment. Urinary bladder lesions that developed in the mice of either sex fed 1.25% phenacetin were also considered to be due to the tumorigenicity of phenacetin. Tumors of other organs in either the phenacetin-treated or the control group were regarded as strain-related spontaneous tumors of B6C3F1 mice.

Ulcer formation and associated tumor production in multiple sites within the stomach and duodenum of rats treated with N-methyl-N'-nitro-N-nitrosoguanidine

The effect of ulcers on the development of gastric tumors by N-methyl-N'-nitro-N-nitrosoguanidine in (MNNG) was studied in male Wistar rats. Ulcers were produced by the application of a steel rod, 5 mm in diameter and frozen at -78 degrees C, to the serosal surface of the forestomach, fundus, pylorus, or proximal duodenum. The existence of the ulcers at these areas was confirmed 1 week later in a preliminary experiment. Experimental groups were given MNNG in their drinking water at a concentration of 100 micrograms/ml for 16 weeks beginning 7 days after the ulcers developed. Administration of MNNG after ulceration resulted in a relative increase in the tumor incidences at each ulcer site, especially the proximal duodenum, which suggested that regenerating cells in the duodenum were the most susceptible cells among the cells of the four sites. The increase in tumor incidence following ulceration may be due to exposure of MNNG to a greater number of regenerating cells during the renewal process that seem to be more responsive to carcinogenic influences that normal cells.

Quantification of platelet-associated IgG with competitive solid-phase enzyme immunoassay

In order to measure platelet-associated IgG (PAIgG), we devised a solid-phase enzyme immunoassay employing a competitive binding of peroxidase-conjugated anti-IgG antiserum between platelets and polystyrene tubes coated with IgG. The amounts of peroxidase bound to the tubes were measured in a spectrophotometer by an enzymatic reaction. This method is highly sensitive, reproducible and can be carried out more simply. the PAIgG values of normal controls averaged 21.6 +/- 6.6 (SD) ng/10(7) platelets. 27 (93%) of 29 patients with idiopathic thrombocytopenic purpura (ITP), who had a platelet count of less than 15 X 10(4)/microliter, had PAIgG values greater than those of controls by 2 SD and averaged 205.5 +/- 323 ng. There was a significant inverse correlation between platelet count and PAIgG value of ITP patients. the PAIgG values of patients with aplastic anemia were within normal range.

An ultrastructural study of precancerous and cancerous lesions of the pancreas in Syrian golden hamsters induced by N-nitrosobis(2-oxopropyl)amine

Transmission electron microscopic studies of precancerous and cancerous lesions in the pancreas of hamsters induced by N-nitrosobis(2-oxopropyl)amine (BOP) are presented. BOP was injected subcutaneously once weekly for 10 weeks and hamsters were sacrificed every 5 weeks after initiation of the experiment. The ultrastructural findings indicated that serial changes occurred in the epithelium of the pancreatic duct. The epithelial cells became cuboidal and showed increased secretions at 5 weeks. Probably precancerous cells with prominent nucleoli and irregular rough endoplasmic reticulum were found in the main duct at 10 weeks. At 15 weeks, pancreatic tumors forming a duct arrangement were seen, in good accord with the histological appearance. Well differentiated adenocarcinoma cells showing a tubular pattern had oval nuclei with granular chromatin. Poorly developed rough endoplasmic reticulum was irregularly distributed throughout the cytoplasm and the cell surface was covered with microvilli. Poorly differentiated adenocarcinoma showed poor gland formation and had distorted nuclei with prominent nucleoli. These cells were loosely joined. Mitochondria and rough endoplasmic reticulum were poorly developed, and the tumor cells were devoid of secretory granules. The most characteristic and common change of the precancerous and cancerous lesions in this experiment was the appearance of numerous microvilli on the luminal surface and loss of cytodifferentiation. These findings were obviously different from those of normal epithelial cells or those seen in inflammation. The findings in this study confirm that the pancreatic carcinoma induced by N-nitrosobis(2-oxopropyl)amine in Syrian hamsters is of duct cell origin. No evidence of acinar cells was obtained.

Thrombocytopenia in Graves' disease: effect of T3 on platelet kinetics

A study was carried out in which the platelet count was decreased in approximately half the patients with hyperthyroidism and gradually increased with treatment. Platelet disappearance curves were curvilinear and the platelet survival was shortened in the hyperthyroid state. Patients maintained in a euthyroid state for 3 months or less continued to have a shortened platelet survival. The survival returned to normal after 6 months or more of euthyroid status. In order to clarify the cause of the decreased platelet count in the patients, animal experiments were performed. T3-injected rats had decreased platelet counts and shortened platelet survival. When platelets obtained from T3-injected rats were transfused to a control group of untreated rats, the platelet survivals were normal. When platelets obtained from the control group of rats were transfused to T3-injected rats, the platelet survivals were shortened. Disappearance of heat-damaged RBC from the circulation was also accelerated in T3-injected rats. This suggests that thrombocytopenia in Graves' disease is caused by an increased sequestration potency of the reticuloendothelial phagocyte system stimulated by thyroid hormone.