Effect of Sobatum on radiation-induced toxicity in mice

Sobatum, the active fraction of the plant Solanum trilobatum was obtained from the petroleum ether/ethyl acetate (75:25) extractable portion. Sobatum was proven to be an anticancer agent by in vitro and in vivo methods. The aim of this study is to evaluate the effect of Sobatum on radiation-induced toxicity in mice. In this assay there are three groups. Group I, the control group, received radiation alone, while groups II and III received Sobatum (100 and 200 mg/kg body weight, respectively) with radiation. Sobatum was administered 24 h before radiation and was continued for 4 alternate days. Body weight, food intake and blood parameters were determined before radiation and every 3 days after radiation for 17 days. The results indicated that there was significantly less body weight gain and food intake in the radiation alone-treated group compared to the Sobatum-treated group. The average leukocyte count and haemoglobin level of the Sobatum-treated group was considerably improved at the end of the experimental period. Hence, it can be concluded that Sobatum reduced the side-effects of radiation-induced toxicity and suggested that it could be used along with radiation therapy.

Modifications of the conditioning regimen for achieving mixed chimerism and donor-specific tolerance in cynomolgus monkeys

BACKGROUND

We demonstrated previously that a nonmyeloablative preparative regimen can induce mixed chimerism and allograft tolerance in cynomolgus monkeys.

METHODS

The current studies were designed to clarify the importance and toxicity of various elements of the allotolerance conditioning regimen by: fractionating or reducing the whole-body irradiation (WBI) dosage; adding deoxyspergualine; or deleting donor bone marrow, cyclosporine, irradiation, or splenectomy.

RESULTS

Monkeys treated without donor bone marrow, cyclosporine, or irradiation did not develop chimerism or long-term allograft survival. One of three monkeys treated without splenectomy developed chimerism but died of a surgical complication. The other two did not develop chimerism and rejected by day 117. Six of six monkeys treated with 300 cGy of fractionated WBI developed chimerism. Five of these recipients had long-term graft survival. Only two of four monkeys treated with 250 cGy developed chimerism, so a 2-week course of deoxyspergualine was added. This led to chimerism in two monkeys, but one died of ureteral stenosis and the other died of allograft rejection. An unanticipated high incidence of ureteral complications felt to be secondary to rejection episodes and ischemic injury was observed in the long-term surviving animals.

CONCLUSIONS

All parameters of the original preparative regimen seem to be essential for consistent success. The degree of lymphocyte depletion was proportional to the WBI dose. Long-term graft survival was observed only in recipients achieving lymphocyte chimerism of > 1.5%. In this model, lymphocyte depletion seems to be the best predictor of chimerism, and significant lymphocyte chimerism seems to be important in achieving tolerance.

Mediastinal irradiation for graft-versus-host disease in a heart-lung transplant recipient

Graft-versus-host disease in solid organ transplantation is very rare, but the prognosis is poor when the condition causes pancytopenia. We report a case of graft-versus-host disease in a heart-lung transplant recipient who at 2 weeks after transplantation had development of features of graft-versus-host disease, including bone marrow aplasia, that could not be attributed to drugs or viral infections. The diagnosis was confirmed by skin biopsy and demonstration of chimerism of peripheral lymphocytes. Augmentation of immunosuppression with intravenous methylprednisolone resulted in improvement in liver function but had no effect on the pancytopenia. Mediastinal irradiation was given with increase in both white blood cell and platelet counts. Unfortunately the patient eventually died of gastrointestinal bleeding and fungemia.

A dose-controlled study of 153Sm-ethylenediaminetetramethylenephosphonate (EDTMP) in the treatment of patients with painful bone metastases

One hundred and fourteen patients with painful bone metastases participated in this randomised, dose-controlled study of the efficacy and safety of 153Sm-ethylenediaminetetramethylenephosphonate (EDTMP), a systemically administered radiopharmaceutical. Fifty-five patients received single doses of 0.5 mCi/kg and 59 patients received single doses of 1.0 mCi/kg. Treatment with 153-Sm-EDTMP produced improvement from baseline in all patient-rated efficacy assessments, including degree of pain, level of daytime discomfort, quality of sleep and pain relief. During the first 4 weeks after dose administration, when the patients evaluated efficacy daily, there were statistically significant changes from baseline with the 1.0 mCi/kg dose but not with the 0.5 mCi/kg dose. The difference between doses in visual analogue pain scores was statistically significant at week 4 (P = 0.0476). Among subsets of patients examined, female patients with breast cancer receiving 1.0 mCi/kg had the most noticeable improvement. The physicians judged that approximately half of the patients in each dose group were experiencing some degree of pain relief by week 2. This value increased to 55% for the 0.5 mCi/kg group and 70% for the 1.0 mCi/kg group at week 4. More patients in the higher dose group (54%) than in the lower dose group (44%) completed the 16-week study. A predictable level of dose-related marrow suppression was the only toxicity associated with 153Sm-EDTMP treatment. Values for platelets and WBCs reached nadirs at 3 or 4 weeks with both doses and recovered by 8 weeks. Even at their lowest point, the values were generally higher than those associated with infectious or haemorrhagic complications. Myelotoxicity was no greater in female patients than in male patients. Long-term follow-up revealed longer survival among breast cancer patients who had received the higher dose than among those who had received the lower dose. The results suggest that the 1.0 mCi/kg dose of 153Sm-EDTMP is safe and effective for the treatment of painful bone metastases.

Travel to sunny countries is associated with changes in immunological parameters

Under laboratory conditions, various studies have shown that changes in immunological parameters must be expected after exposure to ultraviolet (UV) light. The objective of the present study was to evaluate, whether such changes can also be revealed after a vacation to a sunny country without prior adaptation to ultraviolet radiation. In 32 volunteers white blood cells, lymphocyte subpopulations, sIL2-R, sCD14, immunoglobulins and complement factor C3 were determined before and after a vacation in a country with abundant sunshine during winter. The subjects received relevant doses of UVB as confirmed by questionnaires, UVB-dosimetry and the significant increase of 25-hydroxyvitamin D. After vacation, there was a significant decrease of the CD4/8 ratio and the serum concentration of IgG. The serum concentration of sIL2-R, sCD14, IgA and C3 was increased after the journey. Sunshine exposure without prior adaptation may be responsible for significant alterations in the immune system in association with a vacation during winter.

[Changes in the hematopoietic system and in the concentrations of blood-regulatory cytokines after acute irradiation and a combined radiation-thermal lesion]

Acute radiation and combined radiation-thermal injuries (CRTIs) were modelled in the experiments on CBA x C57B16 mice. Changes in the concentrations of endogenic and lipopolysaccharide-induced TNF-alpha in the blood serum were measured in 3 to 24 h after gamma-irradiation at a dose of 7 Gy and a combined radiation-thermal injury. The status of mature and reserve pools of the bone marrow granulocytes was determined from the reaction of leukocytes mobilization to blood in response to the administration of interleukin-1 beta (IL-1 beta) in 48 h after Irradiation and CRTI. The contents of IL-3 and IL-6 in the blood serum, the level of cytokine secretion by the bone marrow cells were determined in vitro in the peak phases of acute radiation and combined injuries. No significant changes in the reaction of the bone marrow cells and in the level of pancytopenia were revealed after acute radiation and CRTIs, which could help in understanding an increase in the death rates after CRTIs. Also, quantitative changes in the TNF and IL-6 concentrations in the blood serum were estimated along with those in the level of secretion of IL-3 by the bone marrow cells of mice exposed to radiation and CRTIs.

Comparisons of geniposidic acid and geniposide on antitumor and radioprotection after sublethal irradiation

The antitumor effects of two iridoid compounds, geniposidic acid (GA) and geniposide (GP), were investigated in mice along with their possible effects on radioprotection after sublethal X-irradiation. Decreases in the growth of the implanted tumor by ascitic cells were a result of intraperitoneal administration of GA and GP at high concentrated levels. This result was achieved by exerting the levels of dosage in a dose-dependent manner. Except on the 12th day after treatment by the dosage of 500 mg/kg, reduced radiation effects of mice treated with the drugs in the 30 min preirradiated period by GA and GP on peripheral leukocytes were not observed significantly by the sublethal whole-body X-irradiation. And except on the 7th day after treatment, when these two compounds were administered i.p. to mice 30 min before 4 Gy irradiation, neither GA nor GP enhanced significantly the postirradiation responses of splenic blastogenesis by PHA. In addition, GA might be a more potent tumor growth inhibitor than GP when combined with the X-irradiation, though there was no significant synergetic effect on their combined antitumor activity. The preliminary results of GA and GP on hematological and blastogenic observations in this study suggested that they may very well, partially, play a role in an effective anticancer product with the ability to decrease undesirable radiation damage to the hematologic tissue after high dose irradiation.

Enhanced hematopoiesis in sublethally irradiated mice treated with various quinolones

We compared the effect of 6 quinolones on growth of murine bone marrow (BM) progenitor cells in vitro, and their in vivo effect on repopulation of BM and on survival of sublethally irradiated mice. The addition of clinically attainable concentrations of ciprofloxacin, sparfloxacin or clinafloxacin, in concert with pokeweed mitogen (PWM) to murine spleen cells, resulted in a significant enhancement in colony stimulating activity. A 1.5-1.8 fold increase in the number of myeloid progenitors (CFU-C) was observed in the presence of quinolone-PWM spleen conditioned medium (SCM) (prepared with the above-mentioned quinolones) compared with control cultures exposed to PWM-SCM only. Three other quinolones showed either no stimulatory-effect (fleroxacin, norfloxacin) or had an inhibitory effect (ofloxacin) on CFU-C growth. The stimulatory quinolones share in common a cyclopropyl moiety at position N1 of the quinolone ring. This moiety is lacking in the other 3 quinolones. The secretion of interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) by murine spleen cells exposed to quinolone-PWM-SCM was significantly enhanced with all 6 quinolones. However, this effect was associated with a parallel increase in CFU-C only with ciprofloxacin (10 micrograms/mL), sparfloxacin (1 microgram/mL) and clinafloxacin (0.05 microgram/mL). The in vivo activity was assessed in sublethally irradiated mice (650 rad) treated with quinolones for 5 d. The number of CFU-C in BM and the number of peripheral white blood cells (WBC) 8 d post-irradiation was significantly enhanced in mice treated with ciprofloxacin (45 mg/kg/d), sparfloxacin (22.5 mg/kg/d) and clinafloxacin (11.25 mg/kg/d) compared to saline treated animals (p < or = 0.05). Clinafloxacin at higher dosage (45 mg/kg/d) resulted in a decrease in myeloid progenitors in BM. A similar increase in progenitors and WBC was observed in animals treated with high doses, above clinical relevance, of ofloxacin, and norfloxacin (90 mg/kg/d), and with fleroxacin (45 and 90 mg/kg/d). Quinolone-treated animals, at the above-cited doses, showed enhanced survival on d18 compared to saline treated animals. The only exception was the higher mortality of clinafloxacin-treated mice. The above observations imply that certain quinolones, sharing specific molecular structure, are potential immunomodulators at clinically relevant concentrations. These compounds should be further studied in neutropenic patients and BM or peripheral blood progenitor cell recipients.

Effects of low power laser-irradiation on differential blood count and body temperature in endotoxin-preimmunized rabbits

Low power laser irradiation has been shown to have various immune-modulatory effects under in vitro conditions but little is known about such effects in animal models. Escherichia coli endotoxin-preimmunized rabbits were used to determine the influence of transcutaneously applied low power laser light on differential blood count and rectal temperature. After three initial immunizations animals were either boostered with 5 ng/kg of endotoxin or injected with pyrogen-free saline and subsequently underwent irradiation using two different wavelengths of red laser light and sham irradiation, respectively. Differential blood count of laser-treated animals was characterized by significantly higher lymphocyte values and lower neutrophil values at twenty hours (boostered rabbits) and twenty-three hours (non-boostered rabbits) after irradiation. Differential blood cell counts returned to baseline values within 23 hours in the boostered animals, whereas in the non-boostered rabbits lymphocytes showed a trend to further increase. Recording of rectal temperature revealed a further rise after laser application, changes being of greater magnitude and longer duration in the non-boostered animals. These results seem to indicate that a single low power laser irradiation can modulate immune-responses depending on the immunological status of the organism.

Biological effects of inhaled 144CeCl3 in beagle dogs

The biological effects of 144Ce were studied in beagle dogs that were exposed to graded activity levels of 144CeCl3 via a single, brief inhalation exposure and observed for their life span. The long-term retained body burdens ranged from 0.06 to 13 MBq/kg with a median of 1.2 MBq/kg. After a short residence time in the lung, most of the 144Ce was translocated to liver and skeleton, where the 144Ce was retained with a half-time approaching the physical half-life of 144Ce, 284 days. Significant radiation doses were delivered to the lung, 28 Gy (median) and 2.5-370 Gy (range); liver, 68 Gy (median) and 6.1-250 Gy (range); and skeleton, 21 Gy (median) and 1.9-100 Gy (range). Lesions induced by the beta-particle radiation were noted in the lung, liver, skeleton, bone marrow, and oral and nasal mucosae closely associated with bone. Early deaths (within 2.5 years) were generally related to hematological dyscrasia, radiation pneumonitis, or hepatocellular degeneration and atrophy. Neoplasms that occurred relatively early, from 2.2-6.8 years after exposure, were noted in the liver, bone, bone marrow and oral mucosa closely associated with bone. Neoplasms that occurred later, beyond 7 years after exposure, were noted in the liver, lung and nasal mucosa closely associated with bone. Increased numbers of neoplasms were not found in two other organs that had relatively high radiation doses, namely the thyroid and kidney. Only one primary bone tumor was noted, but 11 tumors of bone-associated tissues (oral and nasal mucosae and bone marrow) were found. Radiation doses and effects in tissues adjacent to bone, especially those of epithelial or marrow origin, should be considered when determining risks from internally deposited bone-seeking radionuclides, such as 144Ce. The property of 144Ce in depositing on and remaining associated with bone surfaces for long times may be an important factor in the radiation dose to bone marrow and epithelium adjacent to bone.

Effects of oleanolic acid and ursolic acid on inhibiting tumor growth and enhancing the recovery of hematopoietic system postirradiation in mice

Two triterpene acids, oleanolic acid (OA) and ursolic acid (UA) were examined for their ability to inhibit the tumor growth and modify hematopoiesis after irradiation in three experimental systems: (a) in vivo anti-tumor activity of implanted tumor by ascitic cells was found to be augmented by addition of OA and UA at a high concentration and inhibited in a dose-dependent manner; (b) in the sublethal whole-body irradiated mice treated with the drugs in the 30 min preirradiation period, enhanced effects of OA and UA on peripheral leukocytes were observed by a different significance, and (c) when these chemicals were administered i.p. to mice 30 min before 4 Gy irradiation, both OA and UA enhanced the postirradiation responses of splenic blastogenesis by PHA. UA was a more potent tumorigenic inhibitor than OA. Combining with the gamma-irradiation, however, there was no significant synergetic effect on their anti-tumor activity. The beneficial effects of OA and UA on hematopoiesis and immunocompetence under this study, suggested they might partially play a role in anti-cancer and, furthermore, with the ability to decrease undesirable radiation damage to the hematopoietic tissue after radiotherapy.

Transgenic expression of PML/RARalpha impairs myelopoiesis

The translocation found in acute promyelocytic leukemia rearranges the promyelocytic leukemia gene (PML) on chromosome 15 with the retinoic acid receptor alpha (RARalpha) on chromosome 17. This yields a fusion transcript, PML/RARalpha, a transcription factor with reported dominant negative functions in the absence of hormone. Clinical remissions induced with all-trans retinoic acid (RA) treatment in acute promyelocytic leukemia are linked to PML/RARalpha expression in leukemic cells. To evaluate the PML/RARalpha role in myelopoiesis, transgenic mice expressing PML/RARalpha were engineered. A full-length PML/RARalpha cDNA driven by the CD11b promoter was expressed in transgenic mice. Expression was confirmed in the bone marrow with a reverse transcription PCR assay. Basal total white blood cell and granulocyte counts did not appreciably differ between PML/RARalpha transgenic and control mice. Cell sorter analysis of CD11b+ bone marrow cells revealed similar CD11b+ populations in transgenic and control mice. However, in vitro clonal growth assays performed on peripheral blood from transgenic versus control mice revealed a marked reduction of myeloid progenitors, especially in those responding to granulocyte/ macrophage colony-stimulating factor. Granulocyte/macrophage colony-stimulating factor and kit ligand cotreatment did not overcome this inhibition. Impaired myelopoiesis in vivo was shown by stressing these mice with sublethal irradiation. Following irradiation, PML/RARalpha transgenic mice, as compared with controls, more rapidly depressed peripheral white blood cell and granulocyte counts. As expected, nearly all control mice (94.4%) survived irradiation, yet this irradiation was lethal to 45.8% of PML/RARalpha transgenic mice. Lethality was associated with more severe leukopenia in transgenic versus control mice. Retinoic acid treatment of irradiated PML/RARalpha mice enhanced granulocyte recovery. These data suggest that abnormal myelopoiesis due to PML/RARalpha expression is an early event in oncogenic transformation.

Strontium-89 chloride (Metastron) for palliative treatment of bony metastases. The University of Minnesota experience

Strontium-89 chloride (Metastron) is an FDA-approved treatment for palliation of cancer pain. We evaluated blood count changes and pain relief in 28 patients with widespread painful bony metastasis treated with strontium-89 at the University of Minnesota Hospital and Clinics. Eighteen patients had prostate cancer (all hormone-refractory cancer), seven patients had breast cancer, and three patients had lung cancer, all previously treated with either radiation, chemotherapy, or a combination of the two. Serial blood counts were performed weekly up to 8 weeks and at 12 weeks after administering Metastron. Pain scale and blood values were monitored simultaneously. The mean baselines of hemoglobin (Hgb), white blood count (WBC), and platelets (Plts) were 11.4, 5900, and 258,000, respectively. The mean dose of Metastron was 3 mCi (range 2.2-4.4). The median time (range) to nadir was about 6 weeks. The percentage reductions relative to baseline were 32% (range 0-72%) for WBC; 14% (range 0-50%) for Hgb; 15% (range 0-47%) for the red blood cell (RBC) count; and 40% (range 0-85%)for Plts. We did not find a close relationship among the baseline blood count, reduction of subsequent blood counts, or previously irradiated active bone marrow volume. The median time of survival was 23 weeks (range 2-66 weeks). At 12 weeks, 29% of patients had moderate to dramatic improvement of pain, 32% had some relief of pain, and 50% had no improvement in pain. Thirty-two percent of the treated patients required additional palliative external beam radiation to their bony lesions within the study period. Our results show that Metastron for palliation for bony metastases should be used with caution because of moderate to severe bone marrow toxicity, especially in platelets, associated with its use. Careful evaluation of patients given Metastron is needed to assess accurately its full benefit.

High-dose chemotherapy with autologous marrow rescue for malignant brain tumors: analysis of the impact of prior chemotherapy and cranio-spinal irradiation on hematopoietic recovery

The relative impact of age, sex, nucleated cell dose, prior chemotherapy, prior cranio-spinal irradiation (CSI) and bone marrow harvest (BMH) site on hematological recovery after ABMT were analyzed in a multivariate model. The study population comprised 100 patients with a median age of 9 years who underwent ABMT for malignant brain tumors. Two engraftment parameters were evaluated: number of days post ABMT before (1) an absolute neutrophil count (ANC) > or = 0.5 x 10(9)/l and (2) a platelet count > or = 50 x 10(9)/I were achieved for the third consecutive day without transfusions. Increasing cell dose correlated significantly with a more prompt recovery of platelet counts and ANC. Previous chemotherapy significantly delayed both neutrophil and platelet engraftment. The group of patients who also received CSI had a very delayed platelet recovery with a median time to engraftment of 72 days. Neutrophil engraftment was also significantly delayed and occurred at a median of 23 days. This effect of CSI was independent of cell dose or prior chemotherapy. In 20 of these patients, marrow was harvested at least partially from the posterior iliac crests, which might have received significant doses of irradiation. We conclude that engraftment is significantly faster if bone marrow is harvested prior to any chemotherapy administration, and that patients who receive prior CSI may have significant engraftment delay, particularly of the platelet lineage. In this latter group of patients, marrow should not be harvested from the posterior iliac crests. Strategies that might enhance both neutrophil and platelet count recovery should be considered in patients with irradiation damage to a substantial proportion of the total hematopoietic tissue.

Effects of low dose gamma-ray irradiation on peripheral leukocyte counts and spleen of mice

OBJECTIVE

To study the effects of low dose gamma-ray irradiation on peripheral leukocyte counts and spleen weight of mice.

MATERIALS AND METHODS

Two hundred male mice of ICR strain were divided into four groups. Group A served as normal control. Groups B, C and D, the experimental groups were treated with 5, 50 and 100 cGy (exposure dose in air) of whole body gamma-ray irradiation respectively. The leukocyte counts and its differential counts, body weight and the spleen weight of mice were measured on days 1, 5, 12, 19, 26 and 33 after irradiation. The relative spleen weight derived from the data of body weight and spleen weight was also calculated in tested animals.

RESULTS

The leukocytes and its differential counts and relative spleen weight in mice decreased after 100 cGy gamma-ray irradiation. Fifty cGy gamma-ray irradiation could inhibit the leukocyte and its differential counts. The lowest dose, 5 cGy had no considerable damage.

CONCLUSIONS

One hundred cGy of 137Cs gamma-ray irradiation had an inhibitory effect on counts of total leukocyte, lymphocyte, neutrophil, monocyte, spleen weight and body weight, while 50 cGy gamma-ray irradiation had an evident inhibition on peripheral leukocytes and its differential counts in mice. However, 5 cGy gamma-ray irradiation had no obvious inhibition in the tested mice in the period of the investigation.

UVB-irradiation of human bone marrow: potential for donor specific tolerance

Bone marrow mononuclear cell (BMMC) transplant may serve to produce donor specific tolerance for a coincident solid organ graft, but with the risk of graft versus host disease (GVHD). We examined in vitro the immunomodulatory effect of UVB on human BMMCs as potential prophylaxis against GVHD for clinical transplantation. After 10-200 J/m2 UVB-irradiation, BMMCs were examined by proliferative response (in mixed lymphocyte reaction and following phytohemagglutinin stimulation) and by cytokine profile. We also evaluated CFU-GM, CFU-GEMM, and BFU-E progenitor viability by 2-week methyl cellulose cultures following UVB-irradiation. Parallel studies were applied to marrow that was T-cell depleted by soybean agglutination (SBA) or by SBA and sheep erythrocyte rosetting (SBA-E-). We found that (1) UVB produces a dose-dependent inhibition of the proliferative response to stimulators by human BMMCs; (2) increasing doses of UVB-irradiation and increasing levels of T-cell depletion (TCD) are both inversely related to production of lymphokines (IL2, IL3, LIF, IFN-gamma, and GMCSF) and (3) T-cell depletion, but not UVB-irradiation, decreases the production of monokines (IL1, TNF, IL6). Progenitor cell viability was decreased but preserved at 100 J/m2 of UVB. Our findings suggest that UVB compares favorably with TCD as a technique for inhibition of GVHD and therefore that UVB-modulation of bone marrow (BM) inoculum may be useful in the prevention of GVHD in clinical bone marrow transplantation accompanying a solid organ graft.

Modulation of haemopoietic radiation response of mice by diclofenac in fractionated treatment

The effects of diclofenac, an inhibitor of prostaglandin synthesis, were studied on the acute radiation syndrome elicited in mice by fractional irradiation. Several haematological parameters were evaluated in mice irradiated with 5x2 Gy and 3x, 4x, or 5x3 Gy (intervals between fractions 24 h) from a 60Co gamma-ray source. The animals were treated with diclofenac either before each fraction or only once before the last fraction. The survival of mice was recorded after the irradiation regimen of 5x3 Gy followed by a "top-up" dose of 3.5 Gy given 24 h after the last radiation fraction. Statistically significant enhancement of the endogenous spleen colony formation and of leukopoiesis was found in mice treated with diclofenac repeatedly, as compared with both saline-treated irradiated controls and animals administered a single diclofenac dose, if a sublethal total radiation dose had been accumulated. However, following accumulation of a lethal total radiation dose, slightly impaired survival was observed in mice given diclofenac. It follows from the results that diclofenac is a suitable drug for enhancing leukopoiesis impaired by sublethal fractionated irradiation. Nevertheless, undesirable side effects of this drug negatively influence the survival of experimental animals following a lethal accumulated radiation dose.

Multicolor flow cytometry analysis of blood cell subsets in patients given total body irradiation before bone marrow transplantation

PURPOSE

Bone marrow transplantation has often been closely linked with accidental or intentional therapeutical irradiation. In both situations, study of the radiosensitivity of human blood cell subsets is of interest. Using one-color flow cytometry analysis of B lymphocytes, T cell subsets, and natural killer cells, we previously reported that lymphocyte subsets exhibit equal radiosensitivity. Taking advantage of recent developments in the knowledge of leukocyte differentiation antigens and flow cytometry technology we undertook a study of blood cell subsets to search for rare populations exhibiting different radiosensitivity.

METHODS AND MATERIALS

Thirty patients, who were delivered a 12 Gy fractionated total body irradiation as part of their conditioning regimen before transplantation for malignant disorders, were studied using multicolor flow cytometry.

RESULTS

T and B lymphocytes showed a sharp, radiation-induced decrease, with the B lymphocytes (cluster of differentiation (CD) 19+) being the most sensitive. When analyzed by multicolor flow cytometry, all major lymphocyte subsets appeared equally sensitive to the in vivo irradiation; that is, CD3+4+45RO+, CD3+4+45RA+, CD3+4+8-, CD3+4-8+. Therefore, all major lymphocyte subsets sharing the helper phenotype (naive or memory) and the cytotoxic phenotype appeared equally sensitive to in vivo whole body irradiation. In parallel, the CD34+ cell subset remained basically unchanged after whole body irradiation. Finally, the CD3-, 56+, 16+ natural killer cell subset was relatively radioresistant (91 and 74% of its initial value, after 2 and 4 Gy, respectively) as compared to other lymphocyte subsets.

CONCLUSION

Our study provides evidence that T and B cell subsets seem to be highly radiosensitive in vivo. The CD34+ progenitor/stem cells and NK cells seem to be more radioresistant. This latter result might provide clues to the understanding of the pathophysiogeny of radiation-induced aplasia and of the engrafment/rejection process following bone marrow transplantation.

Analysis of weekly complete blood counts in patients receiving standard fractionated partial body radiation therapy

PURPOSE

Hematopoiesis is among the most sensitive systems in the body to radiation. Routine complete blood counts (CBCs) are common in clinical radiotherapy practice. Only a few studies have attempted to characterize the behavior of peripheral blood levels during partial body radiation therapy with field sizes smaller than those used in hemibody or total nodal irradiation. Such information is needed to identify which patients are at risk for cytopenia and require close monitoring.

METHODS AND MATERIALS

In 1993, 412 new patients were seen at Michael Reese Hospital for radiotherapy. A total of 972 weekly CBCs were identified for 155 patients receiving a minimum of 5 weeks of treatment for breast, prostate, lung, gynecological, or head and neck malignancies. Linear regression models were fitted to the weekly CBC values for those patients who had pretreatment CBC values recorded. Factors affecting starting levels, rates of decline, and nadirs during treatment were determined for leukocytes, platelets, and hemoglobin.

RESULTS

Leukocytes declined most dramatically during the first week of treatment (16% from pretreatment to Week 1 levels) and then at a rate of 3.3% per week from Week 1 to Week 7 (p < 0.001). Total mean leukocyte decrease over 7 weeks of therapy was 30%. Platelets declined 9% on average during the first week of therapy and then at a mean rate of 1.4% per week (p < 0.02). A statistically significant decrease in hemoglobin levels could not be detected. No difference in the rate of decrease could be found for different disease sites, age groups, or amount of marrow irradiated. The effects of chemotherapy were variable, depending on blood element and whether therapy was sequential or concomitant. The odds of a nadir < 2000 counts/mm3 for white blood count (WBC), < 50,000 counts/mm3 for platelets, and < 8.0 g/dl for hemoglobin were all well below 5%. A strong correlation existed between starting CBC values and nadirs; patients with lower Week 1 CBC levels were most likely to have the lowest nadirs.

CONCLUSIONS

Low CBC levels during radiation therapy are likely to be the result of other medical problems that cancer patients face. Regional irradiation with small field sizes (< 40% of total body marrow) typically used in clinical radiotherapy is unlikely to be the cause of marrow depression significant enough to warrant medical intervention. Blood levels taken during the first week of treatment (Week 1) can be used to determine risks of developing critical nadirs. Localized breast and prostate cancer patients are unlikely to require routine CBCs if initial levels are normal. Routine CBC levels on all radiation oncology patients without other reasons for hematopoietic depression requires reevaluation, as millions of dollars are spent on unnecessary testing. If weekly CBC blood levels are avoided in localized breast and prostate cancer patients, this alone could potentially result in a savings of as much as $40 million a year nationally.

Flow-cytometric identification and follow-up of mice exposed to x-irradiation: evaluation of a model system

An experimental model system is presented that allows the identification and follow-up of mice exposed to ionizing radiation using flow-cytometric measurements of peripheral blood cells. In an experiment, properties of peripheral blood cells were analysed with flow cytometry for a rapid identification of individuals exposed to radiation. Individuals were then followed longitudinally in an attempt to identify those developing neoplasias. Male CBA mice, 25 days old, were subjected to fractionated x-irradiation (4 x 1.31 Gy) to induce haematopoietic malignancies. By repeated blood sampling followed by flow cytometry, frequencies of micronucleated erythrocytes and of proliferating nucleated cells were determined. Neoplasias were diagnosed by histopathology. Five days after the end of radiation exposure, increased frequencies of proliferating cells, polychromatic erythrocytes and micronucleated normochromatic erythrocytes clearly distinguished the exposed group from the control group. Increased cell proliferation in peripheral blood cells could be used to identify animals with manifest tumours, although these animals were at a late stage of tumour development. Animals with thymic lymphoma (not generalized) could not be identified with the flow-cytometric parameters used. We consider that this model system has a potential use when a small number of risk individuals need to be identified and monitored within a large population.

Immunomodulation at the initiation of phototherapy and photochemotherapy

The numbers and function of circulating lymphocyte subsets are within normal ranges in patients with psoriasis and are not affected by 4 weeks of ultraviolet (UV) therapy, except for a suppression in natural killer (NK) cell activity. However, it is possible that immunomodulation might occur at the initiation of phototherapy with a return to control values on more prolonged UV exposure. Thus, in this study the responses of 15 patients with chronic plaque psoriasis undergoing broad-band UVB therapy, 10 narrow-band (311-313 nm) UVB therapy and 10 PUVA therapy were compared. In each case, samples were taken immediately before starting treatment and 1 week later. Broad-band UVB and PUVA therapy had no effect on NK activity, but a significant reduction was found in the group receiving narrow-band UVB. In vitro lymphoproliferative responses to mitogens and to herpes simplex virus antigens did not alter with therapy, except there was a significant increase in mitogen responses (at optimal mitogen concentrations only) in the narrow-band UVB group. Generally no alterations in overall percentages of circulating mononuclear cells were found in any group. Samples were taken from the epidermis of the forearm and back of the patients receiving narrow-band UVB for the quantification of urocanic acid (UCA) isomers. The total UCA concentration remained unchanged after 1 week of therapy, while the percentage of cis-UCA increased significantly at both sites in the majority of patients. However, this rise did not correlate with the decrease in NK cell activity and the two parameters may not be related causally.

[The evaluation of the mechanism of thrombocytopoiesis from the viewpoint of the phenomenon of emperipolesis]

Cytolytic aggressiveness of bone marrow leucocytes towards megakaryocytes was documented with the aid of a phase contrast Zeitraffer microfilming of alive cells technique. The difference was found between the process above and cell interaction through emperipolesis. The author comes to the conclusion that leucocytes play an active part in platelet production regulation. The data obtained enable new pathognomic methods of treatment to be developed and preventive measures to be devised against blood platelet cytosis involved in the morbid course of quite a number of medical conditions, and further studies to be made.

[Temporal organization of living organisms and the problem of reproducing results of magnetobiological studies]

The analysis of bad reproduction of experimental magnetobiological results was realized onto experimental data for extremely low frequency magnetic field influence on leucocytes level in animal blood. It was shown that one of the causes of bad experimental results reproduction is a dynamism of temporal organization parameters in animals that used as a biological control.

[Quantitative and cytologic changes in various types of blood leukocytes in liquidators 5-6 years after the accident at the Chernobyl power plant]

Radiation-induced effects were studied in leukocytes from 300 males 5-6 years after the Chernobyl accident. Radiation dose received ranged from 5 to 100 sGy. Leukocyte composition of blood was determined in blood smears stained according to Pappenheim and at flow cytometry on Facs tar laser cell sorter. Compared to controls, the majority of the patients had moderate relative and absolute lymphocytosis, eosinophilia and neutrophilopenia. Nuclear structure was changed more frequently in lymphocytes and neutrophils from the exposed subjects, especially in those who had received large dose. The findings evidence that 5-6 years after radiation accident the exposed subjects develop quantitative and qualitative shifts in leukocytes suggesting probable radiation effects on genetic system of the baseline hemopoietic cells.