Biodistribution in rats of 99Tcm-labelled human serum albumin

Three different 99Tcm-human serum albumin (HSA) preparations were simultaneously studied by high pressure liquid chromatography (HPLC) and gamma camera techniques in rats. The products contained variable amounts of 99Tcm-human albumin, 99Tcm-tin colloid and a 99Tcm-low molecular weight complex. The biological half life varied from 55 to 132 min and the bladder excretion for the first 60 min from 2 to 31%. Separated HPLC fractions of 99Tcm-albumin and 99Tcm-tin colloid both showed considerably longer biological half life when injected separately than when injected in the unfractionated preparation. A final evaluation of the quality of such products seem to require evaluation in humans.     

Biodistribution of technetium-99m pertechnetate after total colectomy in rats

This study evaluated the effects of total colectomy on the biodistribution of technetium-99m pertechnetate (^99mTcO₄^?) on the 28th postoperative day in rats. Samples of several organs were harvested for counting the percent of injected radioactivity/g of tissue (%ATI/g). The %ATI/g in colectomy rats was higher in the stomach and ileum than in sham and controls (p<0.05). Increase in mucosa and muscularis size of ileum was observed. Colectomy was associated with lower biodistribution in bladder and thyroid, T3, and T4, than in controls.     

Biodistribution and dosimetry of 99mTc-BTAP-annexin-V in humans

The purpose of this study was to determine the biodistribution and the associated radiation dose of technetium-99m 4,5-bis(thioacetamido)pentanoyl-annexin-V (^99mTc-Apomate), a tracer proposed for the study of apoptosis. Eight patients (including two females) with normal kidney and liver functions were included in the study. An activity of 580ᇮ MBq of ^99mTc-Apomate was injected intravenously, immediately followed by a dynamic study of 30 frames of 1 min each. At about 1 h, 4 h and 20 h p.i., whole-body scans were acquired. All activity distributions were measured using a dual-head gamma camera. Before injection of activity, a transmission scan with a cobalt-57 flood source had been performed to determine patient attenuation. Blood samples were taken every 10 min during the first hour after injection, and at about 4 and 20 h. Urine and faeces were collected during the first 20 h. Organ uptake was estimated after correction for body background activity, attenuation and scatter. Residence times were calculated from the dynamic and whole-body studies and used as input in the Mirdose 3.1 program to obtain organ doses and effective dose. It was found that radioactivity strongly accumulated in the kidneys and the liver [at 70 min p.i., 28%NJ% and 20%dž% of the injected dose (ID), respectively]. Uptake in the target tissues (lymphomas or heart) was negligible from a dosimetric point of view. Extrapolating data from the first 20 h, one finds that approximately 73% of the ID will be excreted in the urine, and 27% in the faeces. The biological half-life of the activity in the total body was 16lj h. Some organ doses - standard deviation (SD) in µGy/MBq were: kidneys 63ᆪ, urinary bladder 20Lj, spleen 15Dž, liver 13Dž, upper large intestine 12Lj, lower large intestine 8dž, testes 6DŽ and red bone marrow 4ǂ.7. The effective dose was 7.6ǂ.5 µSv/MBq, corresponding to a total effective dose of 4.6ǂ.3 mSv for a nominal injected activity of 600 MBq. In conclusion, ^99mTc-Apomate has a high uptake in the kidneys and liver - in fact a factor of 1.3-1.6 higher than that found for the previously studied ^99mTc-(n-1-imino-4-mercaptobutyl)-annexin-V. The biological half-life is shorter, however, but still long compared with the physical half-life of ^99mTc. The faster appearance of activity in the intestines may preclude imaging of apoptosis in the abdomen. The effective dose is within the lower range of values reported for typical ^99mTc compounds.     

Biodistribution and dosimetry of 99mTc-BTAP-annexin-V in humans

The purpose of this study was to determine the biodistribution and the associated radiation dose of technetium-99m 4,5-bis(thioacetamido)pentanoyl-annexin-V (99mTc-Apomate), a tracer proposed for the study of apoptosis. Eight patients (including two females) with normal kidney and liver functions were included in the study. An activity of 580 +/- 90 MBq of 99mTc-Apomate was injected intravenously, immediately followed by a dynamic study of 30 frames of 1 min each. At about 1 h, 4 h and 20 h p.i., whole-body scans were acquired. All activity distributions were measured using a dual-head gamma camera. Before injection of activity, a transmission scan with a cobalt-57 flood source had been performed to determine patient attenuation. Blood samples were taken every 10 min during the first hour after injection, and at about 4 and 20 h. Urine and faeces were collected during the first 20 h. Organ uptake was estimated after correction for body background activity, attenuation and scatter. Residence times were calculated from the dynamic and whole-body studies and used as input in the Mirdose 3.1 program to obtain organ doses and effective dose. It was found that radioactivity strongly accumulated in the kidneys and the liver [at 70 min p.i., 28% +/- 8% and 20% +/- 4% of the injected dose (ID), respectively]. Uptake in the target tissues (lymphomas or heart) was negligible from a dosimetric point of view. Extrapolating data from the first 20 h, one finds that approximately 73% of the ID will be excreted in the urine, and 27% in the faeces. The biological half-life of the activity in the total body was 16 +/- 7 h. Some organ doses +/- standard deviation (SD) in microGy/MBq were: kidneys 63 +/- 22, urinary bladder 20 +/- 6, spleen 15 +/- 3, liver 13 +/- 3, upper large intestine 12 +/- 6, lower large intestine 8 +/- 4, testes 6 +/- 2 and red bone marrow 4 +/- 0.7. The effective dose was 7.6 +/- 0.5 microSv/MBq, corresponding to a total effective dose of 4.6 +/- 0.3 mSv for a nominal injected activity of 600 MBq. In conclusion, 99mTc-Apomate has a high uptake in the kidneys and liver--in fact a factor of 1.3-1.6 higher than that found for the previously studied 99mTc-(n-1-imino-4-mercaptobutyl)-annexin-V. The biological half-life is shorter, however, but still long compared with the physical half-life of 99mTc. The faster appearance of activity in the intestines may preclude imaging of apoptosis in the abdomen. The effective dose is within the lower range of values reported for typical 99mTc compounds.     

Biodistribution, dosimetry, and safety of myocardial perfusion imaging agent 99mTcN-NOET in healthy volunteers.

99mTcN-NOET (bis[N-ethoxy,N-ethyl]dithiocarbamato nitrido technetium (V)) has been proposed for myocardial perfusion imaging. Biodistribution, safety, and dosimetry were studied in 10 healthy volunteers (5 at rest and 5 during exercise). METHODS: Biodistribution was studied by acquiring dynamic images up to 60 min after injection and whole-body images up to 24 h after injection. The MIRDOSE3 analysis program was used for radiation dosimetry calculations. RESULTS: Safety parameters measured to 48 h after injection revealed no clinically significant changes. Cardiac uptake of 99mTcN-NOET was high (2.9%-3%), with biologic half-life of 210-257 min on average. Lung uptake of 99mTcN-NOET was higher (10%-20%) but, on average, biologic half-life was shorter (1-77 min). Clearance from the blood was rapid (5% by 5 min). Radiation dosimetry calculations indicated an effective absorbed dose of 5.11 x 10(-3) mSv/MBq at rest and 5.38 x 10(-3) mSv/MBq after exercise. CONCLUSION: 99mTcN-NOET exhibits high cardiac uptake and an estimated effective absorbed dose comparable with that of the other 99mTc-labeled compounds used in myocardial perfusion imaging.     

Biodistribution of 99Tcm-labelled 5-thio-D-glucose

We studied the biodistribution and tumour localization of 99Tcm-labelled-5-thio-D-glucose (99Tcm-TG). 5-Thio-D-glucose was labelled with 99Tcm by direct stannous ion reduction. The biodistribution of 99Tcm-TG was investigated in normal rabbits and in mice bearing experimental tumours. In rabbits, the plasma and clearance of 99Tcm-TG was 14.5 +/- 2.0 and 11.3 +/- 3.0 ml.min-1 respectively. Urinary excretion at 1 h was 53 +/- 5%. 99Tcm-TG was injected intravenously in mice bearing MC26 colon carcinoma and tissue samples were analysed by gamma scintillation counting at various times. Uptake of 99Tcm-TG in tumour at 1 and 3 h was 1.6 +/- 0.3% and 1.2 +/- 0.3%; the tumour to muscle ratios were 2.7:1 and 4:1 respectively. The autoradiographic biodistribution of 99Tcm-TG in MX-1 human breast xenografted nude mice showed more persistent tumour uptake of 99Tcm-TG than 14C-2-deoxyglucose (14C-DG). 99Tcm-TG accumulated in the centre of the tumours; 14C-DG was decreased in this central region probably because of zones of infarction on necrosis. The discordance between the tumour uptake of 99Tcm-TG and 14C-DG indicates that 99Tcm-TG does not act like a glucose analog, suggesting 99Tcm-TG avidity for zones of infarction or necrosis. The further study of 99Tcm-TG in tumours and ischaemic injury is warranted.     

Membrane lipids of B16 melanoma cells and heat-resistant variants

Membrane lipid composition and fluidity of a series of B16 melanoma cell variants with increased resistance to heat were analysed for changes within the lipid component that may contribute to the acquisition of heat resistance. Within one series of heat-resistant lines the cholesterol content of the cells decreased as their heat resistance increased. The most heat-resistant line, WH75, had 40 per cent less cholesterol than the parent line. No change in the composition of phospholipid fatty acids was found. An increased level of membrane fluidity in WH75 was demonstrated by electron paramagnetic resonance using 5- or 12-doxyl stearic acid. When challenged by heat the increase in membrane fluidity was similar for WH75 and for the parent line. Thus the increased heat resistance of the variants is probably not due to their ability to adapt to heat challenge by increasing membrane thermostability. The inverse relationship between heat resistance and cholesterol content was not demonstrated in two other series of heat-resistant variants. The cholesterol decrease, therefore, is not a universal response of cells as they acquire heat resistance.     

Biodistribution of 99mTc-O4Na changes in adult rats whose mothers were malnourished during lactation.

99mTc-O4Na biodistribution changes in malnourished adults rats. We evaluated this biodistribution in rats whose mothers were malnourished during lactation. METHODS: On the first day of lactation the mothers were separated into 3 groups: control (C) group, protein-restricted (PR) group, and energy-restricted (ER) group. After weaning all pups received a control diet until 60 d, when they were injected with 99mTc-O4Na and killed after 30 min. We evaluated the absolute percentage injected dose (%ID) and the %ID per gram (%ID/g) in thyroid, stomach, heart, bone, kidney, lung, liver, brain, and testes. RESULTS: In the PR group, the %ID and %ID/g were significantly higher in the stomach and lower in the thyroid than in the C group. In the ER pups, the %ID and %ID/g were higher in the liver, stomach, and testes than in the C group. CONCLUSION: The mother's nutritional status during lactation affects the biodistribution of 99mTc-O4Na in the offspring, and this condition must be considered when nuclear medicine examinations are indicated.     

Biodistribution of lipophilic 99mTc complexes of Cyclam Derivatives

Several n-alkyl-cyclam derivatives were synthesized which form stable single component cationic chelates with ^99mTc These results suggest that the cyclam moiety in these derivatives complexes ^99mTc in the same manner as the underivatized macrocycle. Biodistribution studies in mice show that all of these chelates are cleared from circulation by both the kidneys and liver. The ratio and rates of clearance by these organ systems is related to lipid solubility. None of the lypophilic-cationic-^99mTc agents show any significant myocardial uptake. Also, these chelates show no significant ability to penetrate the blood-brain-barrier.     

99mTc labelled model drug carriers - labeling, stability and organ distribution in rats

The surface characteristics of intravenously administered particulate drug carriers decisively influence the protein adsorption that is regarded as a key factor for the in vivo fate of the carriers. We labeled surface-modified polymer particles with the gamma-emitting radioisotope 99mTc in order to test their properties in blood and follow their in vivo fate. The biodistribution was different in various types of polymer particles. As expected, labeled particles were found in the mononuclear phagocyte system in a large scale but markedly different biodistribution for some particles were also shown.     

Biodistribution of Tc-99m methoxy-isobutyl-isonitrile (MIBI) in humans

Hexakis (methoxyisobutilisonitrile) technetium(I), ^99mTc-MIBI, has been proposed for myocardial perfusion studies. We have evaluated the biodistribution of this new agent in normal volunteers at rest and after stress. The biodistribution of ^99mTc-MIBI is characterized by rapid blood clearance and a consequently early myocardial uptake. The initial intense hepatic activity is cleared into the gallbladder at 1 h after injection, and the best target to non target ratio is observed at 60–90 min after injection. Absorbed radiation dose calculations show that the thyroid is the critical target organ (230 mRad/mCi at rest), presumably because of ^99mTc-pertechnetate generated in vivo. Our results indicate that ^99mTc-MIBI is a promising tracer for myocardial perfusion imaging.     

Biodistribution of Tc-99m methoxy-isobutyl-isonitrile (MIBI) in humans

Hexakis (methoxyisobutilisonitrile) technetium(I), 99mTc-MIBI, has been proposed for myocardial perfusion studies. We have evaluated the biodistribution of this new agent in normal volunteers at rest and after stress. The biodistribution of 99mTc-MIBI is characterized by rapid blood clearance and a consequently early myocardial uptake. The initial intense hepatic activity is cleared into the gallbladder at 1 h after injection, and the best target to non target ratio is observed at 60-90 min after injection. Absorbed radiation dose calculations show that the thyroid is the critical target organ (230 mRad/mCi at rest), presumably because of 99mTc-pertechnetate generated in vivo. Our results indicate that 99mTc-MIBI is a promising tracer for myocardial perfusion imaging.     

Biodistribution and radiation dosimetry of 99mTc-HMPAO-labeled monocytes in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) involves the accumulation of monocyte-derived macrophages in the affected synovial tissue. This process of cell migration could be portrayed scintigraphically to monitor noninvasively the effects of therapy on the progress of the disease. For this purpose, labeling of purified autologous monocytes with 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO) at very high specific radioactivity has recently been developed. The aim of this study was to assess the biodistribution and radiation dosimetry of 99mTc-HMPAO-labeled monocytes in adult patients with RA. METHODS: In 8 patients with RA, monocytes were isolated from 100 mL of blood and labeled with 99mTc-HMPAO to a yield of 10 Bq/cell. Multiple whole-body scans were performed up to 20 h after reinjection of an average of 200 MBq of 99mTc-HMPAO-labeled monocytes. Urine and blood samples were collected. The fraction of administered activity in 7 source organs was quantified from the attenuation-corrected geometric mean counts in conjugate views. Radiation-absorbed doses were estimated with OLINDA/EXM software. RESULTS: Autologous monocytes labeled with 99mTc-HMPAO at high intracellular yields showed in vivo kinetics comparable with labeled leukocytes, with initial trapping in the lungs followed by distribution into the liver, spleen, and bone marrow. The radiation-absorbed estimates for 99mTc-HMPAO-labeled monocytes were comparable with those for 99mTc-HMPAO-labeled mixed white blood cells, with an effective dose of 0.011 mSv/MBq. CONCLUSION: 99mTc-HMPAO-labeled monocytes have biodistribution and radiation dosimetry similar to those of 99mTc-HMPAO-labeled mixed white blood cells and might therefore be used for in vivo monitoring of immunomodulating therapy in patients with RA.     

^99Tc^m-精氨酸-谷氨酸-苏氨酸在荷人肺癌H1299裸鼠体内分布和显像

目的通过研究^99Tc^m-精氨酸-谷氨酸-苏氨酸（RET）在荷人肺癌H1299裸鼠体内的分布及显像,探讨其用于肺癌显像的可行性。方法采用^99Tc^m-直接法标记RET,再行^99Tc^m-RET与NSCLC细胞H1299的结合实验。荷人肺癌H1299裸鼠尾静脉注射^99Tc^m-RET后,行不同时间（15、30min,1、2．4、8、24、48h组各4只鼠）体内分布实验,分别测定组织放射性摄取（％ID／g）;另取荷瘤鼠3只,注射4．81MBq^99Tc^m-RET后于0．5、1、2、4．5、5、6h行γ显像。结果^99Tc^m-直接标记RET的标记率为（93．15±2．02）％,与H1299细胞的最高结合率为（3．56±0．37）％。荷瘤裸鼠尾静脉注射^99Tc^m-RET后4h肿瘤放射性摄取达（4．96±1．05）％ID／g,肝脏、脾脏有较多放射性摄取[（15．89±1．84）％ID／g和（10．83±1．66）％ID／g];而心脏和血液的放射性摄取较少,相应的T／NT分别为5．70±0．21和12．40±0．11。注射^99Tc^m-RET后4．5～6．0h肿瘤显影清晰。结论^99Tc^m-RET具有亲肺癌的特性,有可能成为一种亲肺癌显像剂。     

Biodistribution studies of boronophenylalanine-fructose in melanoma and brain tumor patients in Argentina.

A study of the (10)B-enriched p-boronophenylalanine-fructose complex ((10)BPA-F) infusion procedure in potential BNCT patients, including four melanoma of extremities and two high-grade gliomas (glioblastoma and ganglioglioma) was performed. T/B and S/B ratios for (10)B concentrations in tumor (T), blood (B) and skin (S) were determined. The T/B ratio for the glioblastoma was in the 1.8-3.4 range. The ganglioglioma did not show any significant boron uptake. For the nodular metastasic melanoma T/B values were between 1.5 and 2.6 (average 2.1+/-0.4), corresponding to the lower limit of the mean values reported for different melanoma categories. This result might suggest a lower boron uptake for nodular metastasic melanomas. S/B was 1.5+/-0.4. An open two-compartment pharmacokinetic model was applied to predict the boron concentration during the course and at the end of a BNCT irradiation.     

Biodistribution and radiation dosimetry of stabilized 99mTc-exametazine-labeled leukocytes in normal subjects.

Labeling leukocytes with 99mTc-exametazime is a validated technique for imaging infection and inflammation. A new radiolabeling technique has recently been described that enables leukocyte labeling with a more stable form of 99mTc-exametazime. A normal value study of stabilized 99mTc-exametazime-labeled leukocytes has been performed, including biodistribution and dosimetry estimates in normal subjects. METHODS: Ten volunteers were injected with stabilized 99mTc-exametazime-labeled autologous leukocytes to study labeled leukocyte kinetics and dosimetry in normal subjects. Serial whole-body imaging and blood sampling were performed up to 24 h after injection. Cell-labeling efficiency and in vivo viability, organ dosimetry, and clearance calculations were obtained from the blood samples and imaging data as well as urine and stool collection up to 36 h after injection. RESULTS: Cell-labeling efficiency of 87.5% +/- 5.1% was achieved, which is similar to or better than that reported with the standard preparation of 99mTc-exametazime. In vivo stability of the radiolabeled leukocytes was also similar to in vitro results with stabilized 99mTc-exametazime and better than previously reported in vivo stability for nonstabilized 99mTc-exametazime-labeled leukocytes. Organ dosimetry and radiation absorbed doses were similar with a whole-body absorbed dose of 1.3 x 10(-3) mGy/ MBq. Urinary and fecal excretion of activity was minimal, and visual assessment of the images showed little renal parenchymal activity and no bowel activity up to 2 h after injection. CONCLUSION: Cell labeling and in vivo stability appear improved compared with the leukocytes labeled with the nonstabilized preparation of 99mTc-exametazime. There are advantages in more cost-effective preparation of the stabilized 99mTc-exametazime and an extended window for clinical usage, with good visualization of abdominal structures on early images. No significant increase in specific organ and whole-body dosimetry estimates was noted compared with previous estimates using nonstabilized 99mTc-exametazime-labeled leukocytes.     

太空环境对黑色素瘤B16细胞成瘤性的影响

目的观察空间诱变小鼠黑色素瘤B16细胞株的成瘤性，寻找免疫原性发生变异的细胞株。方法将B16细胞株应用细胞低温长期生存系统，搭载于我国第20颗返回式卫星，返地后进行单克隆化，从得到的110株单克隆太空诱变B16细胞株中随机选取4株，常规培养后和对照细胞株同时分别接种C57BL／6J小鼠，腹腔接种组观察生存期，皮下接种组14d后取血、处死，记录瘤重，脾脏重，胸腺重，并进行血清细胞因子检测和瘤体的病理学检测。结果初步确定了适合太空诱变肿瘤细胞株体内筛选实验的方法和筛选指标，并筛选出了1株出瘤时间延迟、瘤重缩小，生存期延长，荷瘤小鼠血清IL-2浓度升高，免疫原性可能发生变异的B16细胞株。结论空间环境可使体外培养肿瘤细胞产生变异，能否通过太空诱变的方法增强肿瘤细胞株的免疫原性需进一步实验验证。     

Biodistribution and radiation dosimetry of 18F-fluoro-A-85380 in healthy volunteers.

This study reports on the biodistribution and radiation dosimetry of 2-(18)F-Fluoro-3-[2(S)-2-azetidinylmethoxy]pyridine ((18)F-fluoro-A-85380), a promising radioligand for the imaging of central nicotinic acetylcholine receptors (nAChRs). METHODS: Whole-body scans were performed in 3 healthy male volunteers up to 2 h after intravenous injection of 137-238 MBq (18)F-fluoro-A-85380. Transmission scans (3 min per step, 8 or 9 steps according to the height of the subject) in 2-dimensional mode were used for subsequent correction of attenuation of emission scans. Emission scans (1 min per step) were acquired over 2 h. Venous blood samples were taken up to 2 h after injection of the radiotracer. Urine was freely collected up to 2 h after injection of the radiotracer. For each subject, the percentage of injected activity measured in regions of interest over brain, intestine, stomach, bladder, kidneys, and liver were fitted to a monoexponential model, as an uptake phase followed by a monoexponential washout, or to a biexponential model to generate time-activity curves. Using the MIRD method, ten source organs were considered in estimating radiation absorbed doses for organs of the body. RESULTS: Injection of (18)F-fluoro-A-85380 was clinically well tolerated and blood and urine pharmacologic parameters did not change significantly. The primary routes of clearance were renal and intestinal. Ten minutes after injection, high activities were observed in the bladder, kidneys, and liver. Slow uptake was seen in the brain. The liver received the highest absorbed dose. The average effective dose of (18)F-fluoro-A-85380 was estimated to be 0.0194 mSv/MBq. CONCLUSION: The amount of (18)F-fluoro-A-85380 required for adequate nAChR imaging results in an acceptable effective dose equivalent to the patient.     

Biodistribution of immunoliposome labeled with Tc-99m in tumor xenografted mice

Objective  Immunoliposome (PEG, GAH, liposome; PGL), consisting of F(ab′)₂ fragment of monoclonal antibody, GAH and polyethyleneglycol-coated (PEGylated) liposome was provided. Immunoliposome, PGL was labeled with technetium-99m (Tc-99m) by two methods: labeling F(ab′)₂ fragment with Tc-99m; Tc-99m-PGL, and entrapping Tc-99m into liposome; PGL[Tc-99m]. The objective of this study was to compare the biodistribution of Tc-99m-PGL and PGL[Tc-99m] in human gastric cancer xenografted mice. Methods  Tc-99m-PGL, PGL[Tc-99m], and Tc-99m-entrapped liposome; Lipo[Tc-99m] were prepared. They were injected into human gastric cancer, MKN45, xenografted mice via the tail vein, and their biodistribution was studied. Results  No marked accumulation of either PGL[Tc-99m] or Lipo[Tc-99m] was observed in the stomach. The uptake of Tc-99m-PGL by the liver, spleen, and lung was higher than that by the tumor. On the other hand, the uptake of PGL[Tc-99m] by the lung and spleen was markedly lower as compared with that of Tc-99m-PGL; the accumulation of PGL[Tc-99m] was lower in the lung and higher in the spleen as compared with that of the tumor. Although the liver uptake of PGL[Tc-99m] was markedly decreased as compared with that of Tc-99m-PGL, it was higher than the uptake of the tumor. The Tc-99m-PGL was strongly taken up by the tumor, with a high level of incorporation also seen in the stomach. These findings suggest the need for further study of the labeling stability. Conclusions  PGL[Tc-99m] appears to show promise for high tumor uptake and retention. This is an important implication for the potential application of immunoliposomes entrapped with Re-186, instead of Tc-99m, in internal radiotherapy.     

太空环境对黑色素瘤B16细胞生物学特性的影响

目的初步研究太空环境对黑素瘤B16细胞生物学特性的影响.方法将B16细胞搭载于第20颗返回式卫星,返地后回收细胞,单克隆化,获得110株太空B16细胞,按顺序编号.从中选取10株的太空B16单克隆细胞株,利用光镜观察其形态变化,MTT方法检测细胞增殖曲线,FCM测定细胞DNA含量,观察太空诱变细胞周期分布.结果与对照细胞相比,太空B16细胞形态改变,有些细胞表面可见其分泌的黑色素颗粒;细胞增殖速率呈多向性变异;太空B16细胞G1期延长,S期缩短.结论太空环境的复合因素可诱导B16细胞生物学特性发生变化.