The 'process of doing' in everyday occupations - a challenge for young adults with cerebral palsy

Background: There is a lack of knowledge about how persons with cerebral palsy (CP) perceive their 'process of doing' while performing everyday occupations. As described in the Model of the Process of Doing (MPoD), performing an occupation is a complex process consisting of six phases (generate idea, plan, initiate, enact, adjust, end) and time management.Aim: To collect the experiences of young adults with CP, classified at Manual Ability Classification System (MACS) level I or II, regarding how they perceive challenges in their occupational performance in relation to the different phases of the 'process of doing'.Method: Semi-structured interviews were performed with ten participants with CP aged 19-30 years, MACS level I or II. The interview material was related to the MPoD phases using directed content analysis.Results: The participants' descriptions of how they perceived their personal 'process of doing' showed problems in all MPoD phases. All participants experienced difficulties in one or more phases, but none had difficulties in all phases. Difficulties were more frequent in some phases than in others.Conclusion/Significance: To understand the complexity of doing everyday occupations in young adults with CP, there is a need to address all phases of the 'process of doing'.

Abstract P6-10-03: Bilateral Prophylactic Mastectomy in Swedish Women at High Risk of Breast Cancer — A National Survey

Background: Prophylactic mastectomy is the most efficient risk-reducing strategy for women with hereditary increased risk of breast cancer. Usually it is combined with immediate breast reconstruction. Unpublished data show that about 60% of Swedish female BRCA1/2 mutation carriers undergo bilateral prophylactic mastectomy (BPM) within eight years after mutation status disclosure. This study attempted a national inventory of all bilateral prophylactic mastectomies performed between 1995 and 2005 in high-risk women without a previous breast malignancy. The primary aim was to investigate the breast cancer incidence after surgery. Secondary aims were to describe the preoperative risk assessment, operation techniques, histopathological findings, complications, and regional differences. Methods: Geneticists, oncologists, and surgeons performing prophylactic breast surgery were asked to identify all women eligible for inclusion in their region. The medical records were reviewed in each region during 2006 and 2007 and the data were analyzed centrally. Information about cancer and death was recorded through 2008. The BOADICEA risk assessment model was used to calculate the number of expected/prevented breast cancers during the follow-up period. Women with incidental cancer in the breast specimens and women treated for ovarian cancer were excluded from the calculation. Prophylactic salpingo-oophorectomy performed before BPM was considered to have reduced the risk of breast cancer by 50%.

Results: A total of 223 women operated on were identified. During a mean postoperative follow-up of 6.6 years (range 2.1-14.0), no primary breast cancer was observed. However, one woman succumbed nine years after BPM to widespread adenocarcinoma of uncertain origin. According to our risk calculation, based on 204 women and 1362 woman-years, approximately 12 breast cancers would have been expected, had BPM not been performed. Eight of these would have occurred in mutation carriers.

The operations had been performed in eight hospitals throughout the country. One hospital performing BPMs declined participation in the study. Median age at BPM was 40 years. A total of 58% were BRCA1/2 mutation carriers. Five women (2%) had a lifetime risk of breast cancer <30% but no woman had a risk below 20%. All but three women underwent breast reconstruction, 208 with implants and 12 with autologous tissue. Four small (≥8 mm), invasive cancers and four DCIS were found in the mastectomy specimens. Three of the women with invasive cancer did not have recent preoperative breast imaging. The incidence of non-breast related complications was low (3%). Implant loss due to infection/necrosis occurred in 10% of the implant-based reconstructions. Conclusions: As only one hospital performing BPMs declined participation, we estimate that the 223 identified women are representative of Swedish conditions. In accordance with previous international series, we conclude that BPM is efficacious in reducing future breast cancer risk in high-risk women. Preoperative imaging and careful histopathological examination of the breast specimens is important, as incidental breast cancers occur. Given the small numbers of operations performed, centralization of this patient group seems justified.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-10-03.

Early versus delayed oxytocin augmentation in nulliparous women with prolonged labour--a randomised controlled trial

OBJECTIVE

To study the effects of early versus delayed oxytocin augmentation on the obstetrical and neonatal outcome in nulliparous women with spontaneous but prolonged labour.

DESIGN

Randomised controlled study.

SETTING

Two delivery units in Sweden.

POPULATION

Healthy nulliparous women with normal pregnancies, spontaneous onset of active labour, a cervical dilatation of 4-9 cm and no progress in cervical dilatation for 2 hours and for an additional hour if amniotomy was performed due to slow progress.

METHODS

Women (n = 630) were randomly allocated either to labour augmentation by oxytocin infusion (early oxytocin group) or to postponement of oxytocin augmentation for another 3 hours (expectant group).

MAIN OUTCOME MEASURE

Mode of delivery (spontaneous vaginal or instrumental vaginal delivery or caesarean section) and time from randomisation to delivery.

RESULTS

The caesarean section rate was 29 of 314 (9%) in the early oxytocin group and 34 of 316 (11%) in the expectant group (OR 0.8, 95% CI 0.5-1.4), and instrumental vaginal delivery 54 of 314 (17%) in the early oxytocin versus 38 of 316 (12%) in the expectant group (OR 1.5, 95% CI 0.97-2.4). Early initiation of oxytocin resulted in a mean decrease of 85 minutes in the randomisation to delivery interval.

CONCLUSION

Early administration of oxytocin did not change the rate of caesarean section or instrumental vaginal delivery but shortened labour duration significantly in women with a 2-hour arrest in cervical dilatation. No other clear benefits or harms were seen between early and delayed administration of oxytocin.

Kondo decoherence: finding the right spin model for iron impurities in gold and silver

We exploit the decoherence of electrons due to magnetic impurities, studied via weak localization, to resolve a long-standing question concerning the classic Kondo systems of Fe impurities in the noble metals gold and silver: which Kondo-type model yields a realistic description of the relevant multiple bands, spin, and orbital degrees of freedom? Previous studies suggest a fully screened spin S Kondo model, but the value of S remained ambiguous. We perform density functional theory calculations that suggest S=3/2. We also compare previous and new measurements of both the resistivity and decoherence rate in quasi-one-dimensional wires to numerical renormalization group predictions for S=1/2, 1, and 3/2, finding excellent agreement for S=3/2.

Controlling the magnetization direction in molecules via their oxidation state

By means of ab initio calculations we predict that it is possible to manipulate the magnetization direction in organic magnetic molecules by changing their oxidation state. We demonstrate this novel effect on the Eu2(C8H8)3 molecule, in which the hybridization of the outer pi ring states with the Eu 4f states causes a redistribution of the orbitals around the Fermi level leading to a strong ferromagnetism due to a hole-mediated exchange mechanism. As a key result, we predict an oscillatory behavior of the easy axis of the magnetization as a function of the oxidation state of the molecule-a new effect, which could lead to new technological applications.

Vanishing magnetic interactions in ferromagnetic thin films

We have used element-specific hysteresis measurements, based on the x-ray magnetic circular dichroism technique, to investigate magnetic trilayer structures composed of Fe and Ni layers. Within a critical regime we have discovered a class of structures in which the exchange interaction, the mechanism responsible for the macroscopic magnetism, can become vanishingly small. The experimental observations are supported by first principles theory and are explained as arising from a cancellation of several competing magnetic interactions. Hence, we have discovered a system with a novel exchange interaction between magnetic layers in direct contact that replaces the conventional exchange interaction in ferromagnets.

Magnetic percolation in diluted magnetic semiconductors

We demonstrate that the magnetic properties of diluted magnetic semiconductors are dominated by short ranged interatomic exchange interactions that have a strong directional dependence. By combining first principles calculations of interatomic exchange interactions with a classical Heisenberg model and Monte Carlo simulations, we reproduce the observed critical temperatures of a broad range of diluted magnetic semiconductors. We also show that agreement between theory and experiment is obtained only when the magnetic atoms are randomly positioned. This suggests that the ordering of diluted magnetic semiconductors is heavily influenced by magnetic percolation, and that the measured critical temperatures should be very sensitive to details in the sample preparation, in agreement with observations.

On the sharpness of the interfaces in metallic multilayers

We show that the three most relevant magnetic properties (magnetic moment, critical temperature, and interlayer exchange coupling) of metallic multilayers can be reproduced with good accuracy by first principles theory, provided that the picture of atomically sharp interfaces is abandoned and one allows instead for both interface alloying and interface roughness. The interface of a metallic multilayer (exemplified by the Fe/V system) is demonstrated to, at best, have interdiffusion essentially over two to three atomic layers on each side of the interface. Our conclusions are the result of combining experimental work with theoretical modeling, and we argue that this approach is the best avenue to obtain accurate information about the interface quality of metallic multilayers.

Defect-induced magnetic structure in (Ga(1)-(x)Mn(x))As

We show that magnetic structures involving partial disorder of local magnetic moments on the Mn atoms in (Ga(1)-(x)Mn(x))As lower the total energy, compared to the case of perfect ferromagnetic ordering, when As defects on the Ga sublattice are present. Such magnetic structures are found to be stable for a range of concentrations of As antisites, and this result accounts for the observed magnetic moments and critical temperatures in (Ga(1)-(x)Mn(x))As. We propose an explanation for the stabilization of the partially disordered magnetic structures and conclude that the magnetization and critical temperatures should increase substantially by reducing the number of As antisite defects.

Double-balloon catheter for isolated liver perfusion: an experimental study

PURPOSE

Further development of a previously described interventional method for isolated liver perfusion (ILP) with a new double-lumen balloon catheter, and evaluation of the side-effects of such isolation.

METHODS

In six pigs a double-balloon occlusion catheter was placed via the transjugular approach with its tip in the portal vein. One of the balloons was positioned in the inferior vena cava (IVC), cranial to the origin of the hepatic veins and the other balloon in the portal vein. By the transfemoral approach, a single-balloon occlusion catheter was placed in the IVC caudal to the origin of the hepatic veins. A third catheter was placed by the transfemoral route with the occlusion balloon in the proper hepatic artery. After inflation of all balloons 99Tc(m)-labelled human serum albumin was recirculated through the liver. The isolation was evaluated by repeated measurement of radioactivity levels in peripheral blood. Laboratory tests of liver and pancreas function, and hemoglobin, were taken before, at the end of, and 3 days after the procedure. Blood gases were tested at the beginning and end of the procedure.

RESULTS

One pig died during the procedure due to technical failure and was excluded from the study. In the other pigs leakage from the isolated liver to the systemic circulation increased slowly, up to 9.7% (mean) during 30 min of recirculation of the perfusate through the liver. Laboratory tests were normal in all pigs except insignificant acidosis directly after the procedure and the slight elevation of s-ALAT after 3 days.

CONCLUSIONS

Only minor leakage from the liver to the systemic circulation was noted during ILP performed with a new, double-balloon catheter. There were no serious side effects.

Sentinel node in breast cancer--a Swedish pilot study of 75 patients

OBJECTIVE

To find out if the sentinel node can be detected in sufficient numbers of women with breast cancer to be useful as a prognostic sign, whether it reflects that state of the entire axilla, and whether it detects micrometastases that would otherwise be missed.

DESIGN

Prospective study.

SETTING

3 teaching hospitals, Sweden.

SUBJECTS

75 patients with breast cancer who were listed to have axillary dissection as well as resection of their tumour.

INTERVENTIONS

Injection of 99Tc nanocolloid 0.4 ml and patent blue dye 1 ml around the tumour or under the skin above the tumour, followed by preoperative lymphoscintigraphy and then identification of the sentinel node during operation either because it had turned blue or with a gamma probe. Removal of the sentinel node and complete axillary dissection.

MAIN OUTCOME MEASURES

Identification of the sentinel node and presence of metastatic nodes in the axilla.

RESULTS

The sentinel node was identified in 69/75 (92%). It correctly predicted the state of the axilla in 66/69 (96%), and detected metastases in 24 of the 27 with invaded nodes in the axilla (89%). The false negative rate was 11%. In 14/27 with axillary metastases (52%) the sentinel node was the only involved node. In 3/24, metastases were detected by immunohistochemistry alone.

CONCLUSION

Biopsy of the sentinel node predicted the presence or absence of axillary metastases with acceptable accuracy. However, before axillary node dissection is rejected in favour of sentinel node biopsy alone, large multicentre studies are needed to establish the true false negative rate.

Isolated liver perfusion using percutaneous methods: an experimental study in the pig

PURPOSE

To develop a method for isolated perfusion of the liver using radiological methods.

METHODS

Twenty-one pigs, weighing about 20 kg, were divided into three groups. By transjugular and transfemoral approaches two occlusion balloons were placed in the inferior vena cava cranial and caudal, respectively, to the origin of the hepatic veins. One occlusion balloon was placed transfemorally in the common hepatic artery. Another occlusion balloon was inserted in the main branch of the portal vein via the transjugular-transhepatic approach in 11 pigs (groups 1 and 2), and in 10 pigs (group 3) by a percutaneous transhepatic route. After inflation of the balloons, patency of the isolated liver circulation was evaluated by recirculation of 99Tcm-labelled human albumin during 30 min. Blood tests were obtained after 1, 3, 5, 10, 15, and 30 min to evaluate leakage from the liver to the systemic circulation.

RESULTS

Increasing leakage to the systemic circulation from the isolated liver circulation was observed in groups 1 and 2. In the third group the leakage was less than 10%.

CONCLUSION

In an experimental animal model, isolated perfusion of the liver with minor leakage to the systemic circulation may be achieved using radiological methods.

Homeopathic Resistant Malaria

Multiresistant Plasmodium falciparum malaria is a major threat to travelers to subSaharan Africa. However, even if chemoprophylaxis does not prevent clinical malaria in some individuals, it does lead to a reduction in the severity of the disease.1 In Sweden, we have recently seen five patients with malaria (three due to P. ovale and two due to P. falciparum) who have used homeopathic drugs for prophylaxis during visits to West Africa. We are concerned about this incidence and afraid that reduced confidence in modern medical malaria prophylaxis will encourage some individuals to try totally ineffective alternatives. Three women (57, 40, and 39 years old) visited Guinea Conacry in January 1995 as members of a group of 24 persons learning about African dances. The 57-year-old woman took mefloquine irregularly but vomited each time after intake. She also used Spenglersan M, which is a homeopathic drug that is administered (one drop daily in the bend of the arm) as malaria prophylaxis. The two other women used Spenglersan M only. They all fell ill with P. ovale malaria despite ongoing intake. Spenglersan M is said to contain both antigen from P. falciparum and antibodies against the parasite diluted to 1:1,000,000,000 concentration. The fourth case was a 26-year-old man who visited Ghana and Burkina Faso in October and November 1994. He used China D-6 for prophylaxis. This is a homeopathic preparation of the bark from the cinchona tree. Not even trace amounts of quinine were found in the tablets with a very sensitive high-performance liquid chromatographic method.2 Four days after returning from Africa he fell ill with P. falciparum malaria and received sulphadoxine-pyrimethamine treatment. After clinical relapse (RI), mefloquine was given and the patient was eventually cured. The fifth case was a 34-year-old woman admitted to hospital because of P. falciparum malaria after a visit to Guinea Conacry in January 1995. She had taken a homeopathic drug, Charaka comp 118, as prophylaxis. The drug is said to contain different extracts from herbs diluted 30 times. At first she refused to stay in hospital, but 2 days later she was readmitted and treated in the intensive care unit because of severe malaria with hypotonia and anemia. She had hyperparasitemia with 23% infected erythrocytes. Exchange transfusion was done, quinine was given, and the patient recovered without sequelae. The mortality is about 1% in people with P. falciparum infection.3 We therefore urge the readers to stand up against the dangerous use of homeopathic drugs and instead motivate travelers to use protective malaria prophylaxis.

Influence of dearterialization on distribution of absolute tumor blood flow between hepatic artery and portal vein

BACKGROUND

Conflicting results have been obtained regarding blood flow distribution to liver tumors. The emphasis on portal vein perfusion has had a great impact on the design of treatment protocols.

METHODS

Double microsphere technique with reference organ sampling was used for the measurement of hepatic artery and portal vein blood flow of an implanted liver tumor in 42 rats after permanent dearterialization and repeated dearterialization (2 hours/day) compared with untreated sham-operated controls.

RESULTS

Portal venous blood flow constituted 16% of total tumor blood flow and slightly increased after permanent and repeat dearterializations, though the elevation was not statistically significant as compared with sham-treatment (P > 0.05). In another 3 groups, the treatment was extended to 10 days, and tumor blood flow was measured in central and peripheral parts separately. Arterial blood flow further decreased in tumor periphery and was still lower in the tumor center (P < 0.01 versus tumor periphery), and portal blood flow declined concomitantly to 4% of total tumor blood perfusion. However, no difference in portal blood flow between the tumor center and periphery could be demonstrated (P > 0.05). Furthermore, portal supply increased neither in tumor periphery nor in tumor center after both permanent and repeated dearterialization (P > 0.05).

CONCLUSION

The authors' results showed that portal blood flow did contribute to tumor circulation, but made up only 16% of blood flow when tumors were small and declined to 4% of entire tumor blood supply when tumors became large. Portal perfusion also declined as tumors grew larger and did not compensate for the withdrawal of tumor arterial blood supply after dearterialization.

Rearterialization of liver tumors after various dearterialization procedures

Repeat dearterializations seem to be a means to prevent collateral formation, which is partly responsible for the failure of hepatic artery ligation (HAL) or permanent dearterialization when used to treat liver tumors. In this study restoration of tumor blood flow was evaluated after various procedures: HAL (n = 12), permanent dearterialization (n = 18), repeated dearterializations for 2 hr/day (n = 12), and sham dearterialization (n = 12). Tumor blood flow was measured 10 days after sham dearterialization, permanent dearterialization, and repeated dearterializations for 2 hr in order to further illustrate the effect of prolonged dearterialization on tumor rearterialization. Hepatic and tumor arterial blood flow was measured using the reference organ method (NEN, 141Ce microspheres with diameter 15 microns). Our results showed that during a transient dearterialization blood flow decreased to 1% (0.01 +/- 0.01 ml/min/g) of the flow in the controls (0.82 +/- 0.10 ml/min/g) (P < 0.01). After HAL tumor blood flow recovered to initial levels after 48 hr (0.73 +/- 0.17 ml/min/g). Even in rats subjected to a permanent dearterialization blood flow was reestablished at Day 6 (0.59 +/- 0.21 ml/min/g). In contrast, after repeat daily 2-hr dearteralizations blood flow remained significantly very low during the 6th transient dearterialization (0.11 +/- 0.03 ml/min/g) compared with both sham-operation and HAL as well as permanent dearterialization (P < 0.01). During the 10th daily dearterialization tumor blood flow was still significantly low compared with both controls (P < 0.001) and permanent dearterialization (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Autocorrelation spectroscopy for particle sizing and stability tests of radiolabelled colloids

In many nuclear medicine applications a well defined particle size and stability of administered colloids is of great importance. A fast and reliable sizing technique for routine quality control is therefore essential. This paper evaluates autocorrelation spectroscopy with an instrument capable of analysing several peaks simultaneously. A total of nine 99mTc-labelled colloids and one 99Y-labelled colloid were studied. The autocorrelation spectroscopy measurements were compared with the standard sizing technique of microfiltration. A good agreement between the sizing techniques was found for most of the colloids. The reproducibility of successive measurements was within +/- 12% and +/- 40% when using unimodal analysis and SDP analysis, respectively. Autocorrelation spectroscopy was found to be well suited for particle sizing and stability tests of radiolabelled colloids.

Lack of correlation between fecal blood loss and drug-induced gastric mucosal lesions

Increased fecal blood loss was produced in healthy volunteers by the administration of two nonsteroidal anti-inflammatory drugs (NSAID), naproxen or fenflumizole. Basal as well as drug-induced gastrointestinal blood loss was measured using 51Cr erythrocyte labeling. Median rise in daily fecal blood loss was 432%. All subjects were endoscoped at the initiation and at the completion of the study. Endoscopic findings were assessed quantitatively by two observers in two different ways. All subjects but three had gastric mucosal lesions at follow-up endoscopy. There was a good correlation between the endoscopic assessments but no statistical correlation between the endoscopic assessment and the increase in fecal blood loss. The data suggest that factors other than gastric mucosal lesions have to be taken into account when investigating NSAID-induced gastrointestinal bleeding.

The "critical colloid dose" in studies of reticuloendothelial function

The [99mTc]sulfur colloid distribution in rat organs was investigated after the administration of different amounts of colloid particles. Saturation of the liver and spleen was not observed. Blood clearance was significantly reduced 15 min after injection above approximately 3 X 10(9) particles per kg body weight. With an increasing number of injected particles, lung uptake increased and bone marrow uptake decreased. Microfiltration studies showed that the colloid is unaffected by dilution with saline but may be affected after incubation in normal rat plasma. We conclude that the distribution of [99Tc]sulfur colloid in organs varies with the number of injected particles and therefore, is not dependent upon the blood flow to the reticuloendothelial organs alone. The "critical colloid dose" may differ among the reticuloendothelial organs and cannot, therefore, be evaluated by blood clearance measurements alone. The considerable influence of the number of injected colloid particles on bone marrow uptake should also be recognized when carrying out dosimetric calculations.

Hepatic reticuloendothelial function in rats with various portasystemic shunts and total liver arterialization

Hepatic reticuloendothelial function was measured in 6 experimental groups of rats with various portasystemic shunts or total liver arterialization by computer calculation of the hepatic uptake rate of intravenously injected 99mTc-sulphur colloid. Marked reduction of the hepatic reticuloendothelial system (RES) function was found both 1 and 3 weeks after the construction of a mesentericocaval or conventional end-to-side portacaval shunt. Hepatic RES function was also lowered both 1 and 3 weeks after a modified portacaval shunt, but the reduction was much less pronounced. Total liver arterialization produced a similar mild reduction of hepatic RES function after 1 week; however, there was no longer any significant reduction after 3 weeks. This study concludes that total liver arterialization ameliorates the negative effect that portasystemic shunting has on hepatic RES function.

Radiolabelled colloid uptake distribution and pulmonary contents and localization of lysosomal enzymes in cholestatic rats

Studies of the activity uptake of radiolabelled 99mTc2S7 colloid in different tissues showed a moderately increased uptake in the lung 1 week and a greatly increased uptake 3 weeks after permanent bile duct occlusion. Three weeks after bile duct occlusion the activity uptake was also slightly increased in the spleen and moderately reduced in the liver. In pulmonary tissue of cholestatic rats, the levels of alkaline and acid phosphatase, beta-glucuronidase, and beta-hexosaminidase were determined after 6 weeks. The pulmonary contents of beta-glucuronidase was increased tenfold, and that of beta-hexosaminidase was increased fourfold in cholestasis. Histochemical investigation showed that the lysosomal enzymes were located in the macrophages, which in cholestasis were abundant in alveolar walls and inside alveoli. Macrophages were also frequently seen to engorge pulmonary veins.

Reticulo-endothelial function in rats with obstructive jaundice

Reticulo-endothelial function was evaluated by measuring the biokinetics of a standardized 99mTc-sulphur colloid using scintillation camera technique in rats with biliary obstruction. There was no difference in the uptake of the colloid in the liver (K1) between sham operation and biliary obstruction at 1 week and 3 weeks. However, when corrected for changes in liver volume, the corrected colloidal uptake rate (cK1) of the liver was significantly decreased in 1 week's biliary obstruction (P less than 0.005 compared with sham operation) and 3 weeks' biliary obstruction (P less than 0.025 compared with 1 week obstruction). Colloidal uptake rate of the extrahepatic reticulo-endothelial system (K2) was significantly increased (P less than 0.005) in rats with 3 weeks' biliary obstruction. Activity distribution of 99mTc-sulphur colloid in 3 weeks' biliary obstruction was significantly decreased in both total organ basis and per gram basis (P less than 0.005). The results demonstrated a depression of RE activity of the liver in biliary obstruction.

Influence of a reticuloendothelial-suppressing agent on liver tumor growth in the rat

Reticuloendothelial (RE) function was evaluated by measuring the biokinetics of a standardized 99Tcm-sulphur colloid. Methyl palmitate was administered intravenously on two consecutive days. A statistically significant reduction in the colloid uptake rate of the liver was registered after methyl palmitate administration. Histological examination revealed no signs of destruction of RE cells or microembolization. Inoculation of an experimental nitrosoguanidine-induced transplantable adenocarcinoma to the liver was performed in 16 rats one day after methyl palmitate administration and in 16 controls. Tumor size was significantly larger in methyl-palmitate-treated animals at 7 and 14 days after inoculation. Survival was significantly decreased in methyl-palmitate-treated rats. These rats showed signs of fatty vacuolization and necrosis of liver parenchyma earlier than controls. Analyses of beta-hexosaminidase and lactate dehydrogenase revealed no deviation of enzyme levels either before or after tumor inoculation. The results indicate that a temporary suppression of RE function at the time of tumor inoculation may influence subsequent tumor growth.

Clinical comparison of bone scintigraphy with 99Tcm-DPD, 99Tcm-HDP and 99Tcm-MDP

The bone-imaging agents MDP, DPD and HDP were compared radiochemically (only minor differences were found) in 12 patients with prostatic and 12 patients with breast carcinoma. Each patient received both MDP and either DPD or HDP. The scintigraphic examinations were compared visually and quantitatively. The uptake ratio normal bone/soft tissue was higher for DPD and HDP than for MDP. The ratio pathologic bone/normal bone was highest for MDP, particularly for prostatic carcinoma. The differences in this ratio for breast carcinoma were in general non-significant. The observed differences were minor and of little practical importance.

Lymphoscintigraphy in patients with malignant melanoma: a quantitative and qualitative evaluation of its usefulness

Lymphoscintigraphy using 99mTcSb2S3 colloid was performed in 32 patients with malignant melanoma. Subcutaneous injections were made peritumorally in 20 patients and dorsopedally in 12 patients. Regional lymph node dissections were carried out on the following day in 16 patients and the resected lymph nodes were weighted, measured for radioactivity, and examined by light microscopy. Lymph flow to regional lymph nodes was shown in all but 2 patients. Twenty-nine of 239 lymph nodes contained metastases. Radioactivity was demonstrated in 17 of these nodes. In 5 of 11 patients with metastatic disease, the highest uptake was found in cancerous lymph nodes. The specific activity-uptake distribution in isolated ilio-inguinal lymph nodes after a dorsopedal injection was log-normal with a mean of 0.05%/g indicating a good saturation of colloid particles. This investigation concludes that the observed lymph flow directions in patients injected peritumorally are of value for the follow-up. Quantitative lymphoscintigraphy in patients with melanoma of the lower extremities is, however, of no value for excluding ilio-inguinal lymph node metastases.

Release of beta-hexosaminidase after administration of different agents affecting the reticuloendothelial system. An experimental study in rats

Plasma levels of a lysosomal enzyme, beta-hexosaminidase (beta-N-acetylglucosaminidase, EC 3.2.1.30) were studied in Wistar rats after administration of 99mTc -sulfur colloid, 198Au colloid, gelatine (Haemaccel), alcohol, methylpalmitate and zymosan. The activity of beta-hexosaminidase was increased 10, 30 and 60 min after the zymosan injection. After 24 and 48 h, enzyme levels had returned to those at outset. The transient release of beta-hexosaminidase probably occurred only during the phagocytosis of zymosan which was evaluated by histological examination of lung, liver and spleen. After the injection of all other agents tested, no significant aberration of beta-hexosaminidase levels was seen. Activity distribution of the radio-labeled colloids revealed differences in organ uptake which were attributed to a difference in colloid particle size. Although the colloids tested have been used extensively for determination of reticuloendothelial function and histological studies suggest phagocytosis of the particles, their administration did not affect plasma beta-hexosaminidase levels. Since lysosomal enzymes are cleared from the blood predominantly by liver macrophages, the primary location of particle phagocytosis may explain the present findings.

Reticuloendothelial function in normal and tumor-bearing rats. Measurements with a scintillation camera technique

The function of the reticuloendothelial system (RES) was evaluated after the inoculation of an experimental tumor in rats. Four groups were studied according to tumor size and site. Reticuloendothelial function was evaluated by measuring the biokinetics of a standardized [99Tcm]-sulfur colloid. Estimation of the uptake rate of the labeled colloid into the liver and other parts of the RES was performed through the use of a two-compartment model. Animals with small liver or subcutaneous tumors showed an increased activity of both the hepatic and the extrahepatic RES. Animals with large retroperitoneal tumors showed a significant decrease in the RE function of the liver. In these animals the function of the extrahepatic RES was not changed compared to controls but was, however, significantly decreased compared to animals with smaller tumors. The findings may reflect a difference in the impact of tumor size on RE function extra- and intrahepatically.

Particle sizing and biokinetics of interstitial lymphoscintigraphic agents

The biokinetics of inert lymphoscintigraphic agents strongly depends on their particle size. Different techniques for characterization of colloids are discussed. Experiments have been performed on eight different colloids. The particle size has been investigated with scanning electron microscopy. Activity distributions have been obtained with ultrafiltration and gel-column scanning technique. The colloids suggested for lymphoscintigraphy were found to have a median size of about 40-50 nm except one minimicro-aggregated human serum albumin colloid which has a median particle size around 10 nm. The biokinetics were studied with a scintillation camera in rabbits after a subcutaneous injection. Time-activity curves were generated. After 5 hr the rabbits were dissected and the activity content in different tissues measured. A compartment model for the biokinetics was designed and rate constants evaluated. The total and specific activity uptake in parasternal lymph nodes was highest for the small-particle colloids. The compartment model showed a good fitting to the experimental data.

Dosimetry in lymphoscintigraphy of Tc-99m antimony sulfide colloid

A quantitative kinetic technique using a scintillation camera has been developed for investigating lymph drainage and the uptake in the lymph nodes of 99mTcSb2S3 colloid injected subcutaneously. Twenty-two patients with primary malignant melanoma were examined. Lymph-node dissection was performed and 185 lymph nodes were individually measured for radioactivity. The kinetics of colloid uptake in individual nodes can be expressed by a simple two-compartment model. The outflow of colloid from the injection site was found to be monoexponential, and the tissue volume containing the injected colloid at the injection site increased asymptotically with time. A model has been developed for calculating absorbed doses at the injection site and in organs with colloid uptake. The following absorbed doses were estimated (muGy/MBq): whole body 0.7-4.5, gonads 0-22, liver 1.0-3.9, lymph nodes up to 1000 and injection site about 10,000. Possible biological effects in the skin and effective dose equivalents have been estimated when using other lymphoscintigraphic agents.