钆双胺对^99Tc^m—MDP骨显像影响的实验研究

目的探讨MRI对比剂钆双胺注射液（欧乃影;Gd—DTPA—BMA）应用后对家兔^99Tc^m-MDP骨显像的影响。方法采用自身前后对照方法,实验组（注射欧乃影＋^99Tc^m-MDP）与自身对照组（注射生理盐水＋^99Tc^m-MDP）处理相隔7d。（1）取家兔5只,注射欧乃影或生理盐水后30min注射^99Tc^m-MDP,并于注射^99Tc^m-MDP后5、10、30、60、120、180、240和360min、24h时行骨显像,勾画ROI,计算靶／本底（T／B）值,观察家兔显像剂分布及代谢情况。（2）取家兔30只,按欧乃影或生理盐水与^99Tc^m-MDP的注射间隔（30、60、120、240和360min、24h）分为6组,每组5只。均于注射^99Tc^m-MDP后120min行骨显像,勾画ROI,计算T／B值。（3）采用TLC测定2种药物相互作用后在体内的放化纯差异。以配对t检验进行统计分析。结果注射欧乃影后30min再注射^99Tc^m-MDP,5min时肝、脾开始显影,其T／B比值120min时达最高峰（肝、脾分别为4．56±0．32和3．56±0．41）;而2组椎体24h时T／B值均达最大值（实验组为4．32±0．07,自身对照组为6．31±0．09）,但各时间点实验组均较自身对照组低。两药物注射间隔为30、60、120和240min时,可出现肝、脾异常显影,对应的实验组T／B（肝：2．47～4．22;脾：1．85～3．23）明显高于自身对照组（肝：1．52—1．58;脾：1．25～1．29）,但实验组椎体的T／B（3．08～4．28）则较自身对照组低（4．82～4．85）,以上差异均有统计学意义（t=7．750—31．916,均P〈0．05）。余时间间隔组,肝、脾未见明显摄取^99Tc^m-MDP。TLC曲线示,实验组在Rf为0—0．2处形成小峰,^99Tc^m-MDP放化纯降为（63．51±2．24）％。结论注射欧乃影后短时间内行^99Tc^m-MDP骨显像,肝、脾会出现异常摄取;间隔360min再行^99Tc^m-MDP骨显像可避免此现象发生。     

Radionuclide cisternography and computed tomography in 30 healthy volunteers

Summary Radiological assessments of patients with symptoms of impaired cerebrospinal fluid (CSF) circulation are usually based on observations of anatomical and functional alterations using computed tomography (CT) and radionuclide cisternography (RC). In order to define criteria of normality for these two techniques, 30 healthy volunteers have been studied. In the studies of CSF flow the radiopharmaceutical ^99mTc-DTPA was used and single photon emission computed tomography (SPECT) was performed as a complement to planar scintigraphy. In 16 of the 30 volunteers the pattern of CSF flow was normal according to conventional criteria. In these subjects the radioactivity was symmetrically located over the parietal cortex 24 h after the injection and no intraventricular activity could be recorded. In 11 (41%) of the subjects, radioactivity could be observed in the lateral ventricles 6 h after injection. One of these subjects had a reflux of radioactivity into the lateral ventricles. The intraventricular radioactivity persisted for at least 24 h. This subject also had signs of obstruction of CSF flow over the convexities. Asymmetric distribution of radioactivity within the CSF spaces was observed in the images obtained after 6 but not 24 h in two cases. One of those also demonstrated transient intraventricular radioactivity. The results of the computed tomography were interpreted to be normal in 19 (63%) of the 30 volunteers. One subject had an asymmetric ventricular system. The CT scans of six subjects (20%) differed considerably from the others as they displayed wide cortical or vermian sulci at the borderline of normal variations. The case with the pathological RC belonged to the group of subjects who had wide sulci. He also had a wide third ventricle. No subject had dilated lateral ventricles on CT. It is concluded that transient but not persistent (up to 24 h) intraventricular reflux should be interpreted as a normal finding in radionuclide cisternography. The probable mechanism for this reflux is discussed.     

Radionuclide imaging clinical study. Corporeal 133Xe washout for detecting venous leakage in impotence

A quantitative test, corporeal 133Xe washout, was developed to detect venogenic impotence. Data were acquired in frame mode after intracorporeal injection of 0.1 ml (1-2 mCi or 37-74 MBq) of 133Xe in saline on one side of the midline just behind the glans in the flaccid state for 20 min. A time-activity curve (TAC) was generated from the region of interest (ROI) at the site of injection and a computer routine was then used to calculate clearance half-time (T1/2) in minutes and flow rate (Q) in ml/100 g tissue/min from corporeal 133Xe clearance. The data from 12 controls and 21 patients with venous leakage were analysed. In patients with venogenic impotence, T1/2 (mean +/- S.D.) was greatly increased (24.4 +/- 10.7 min vs 10.7 +/- 4.6 min in controls, P less than 0.005) whereas Q markedly decreased (2.4 +/- 1.3 ml/100 g tissue/min vs 5.4 +/- 2.3 ml/100 g tissue/min in controls, P less than 0.005). The sensitivity and specificity for detecting venous leakage at the optimal threshold of T1/2 equal to 13 min and Q equal to 3.7 ml/100 g tissue/min were 95 and 75%, respectively. The corporeal 133Xe clearance half-time and flow rate are two simple and clinically useful indices for detecting venous leakage.     

High-dose treatment with (186)Re-HEDP or (153)Sm-EDTMP combined with amifostine in a rabbit model.

The aim of this experimental study was to investigate the myeloprotective potential of amifostine in rabbits receiving high-dose treatment with either (153)Sm-ethylenediaminetetramethylene phosphonate (EDTMP) or (186)Re-hydroxyethylidene diphosphonate (HEDP) and to check for drug interactions impairing the skeletal uptake of these radiopharmaceuticals by amifostine. METHODS: To a total of 24 rabbits, we administered 1,000 MBq of either (153)Sm-EDTMP (n = 12) or (186)Re-HEDP (n = 12). Six animals of each group received 500 mg amifostine intravenously 10-15 min before injection of the radiopharmaceutical, whereas the other 6 animals served as controls. Up to 8 wk after treatment, blood samples were collected every 3-5 d to measure platelet and leukocyte counts. Furthermore, whole-body images were acquired at 3 min, 3 h, and 24 h after injection of the radiopharmaceutical to quantify the skeletal uptake. RESULTS: For (186)Re-HEDP, the mean decrease in platelets was significantly less in the amifostine group (35.5% +/- 2.4%) than in the control group (61.3% +/- 5.4%, P < 0.001). Similar results were found for (153)Sm-EDTMP (36.5% +/- 8.3% vs. 52.3% +/- 14.0%, P < 0.05). No significant differences in leukocyte counts were found for (186)Re-HEDP (75.3% +/- 12.3% in the amifostine group and 72.5% +/- 4.1% in the control group, P > 0.05), whereas rabbits treated with (153)Sm-EDTMP plus amifostine showed a significantly greater decrease in leukocytes (69.2% +/- 10.8%) than did the control group (56.6% +/- 4.0%, P < 0.05). Bone uptake in percentage of initial total whole-body activity was significantly decreased in animals treated with amifostine compared with the control groups for both (186)Re-HEDP (15.8% +/- 3.1% vs. 30.9% +/- 1.9%, P < 0.001) and (153)Sm-EDTMP (31.7% +/- 8.9% vs. 44.0% +/- 6.5%, P < 0.05). CONCLUSION: For amifostine, we found a highly significant cytoprotective effect on platelets but no leukoprotective effect. The latter probably relies on the intrinsic myelotoxicity of high-dose amifostine, which seemed to potentiate the leukodepression of the radiopharmaceuticals. The lower bone uptake in amifostine-treated animals may be caused by the chemical structure of amifostine, which is a potentially complex-forming compound that may be able to displace bisphosphonates from the rhenium- and samarium-bisphosphonate complexes, resulting in altered biodistribution patterns.     

Evaluation of 99mTc-dextran as a lymphoscintigraphic agent in rabbits

Dextran (clinical grade, average mol. wt. 82,200) was labelled with 99mTc and the labelling efficiency was checked by paper and thin-layer chromatography and electrophoresis. The amount of free 99mTcO-4 was always less than 1%. The radiopharmaceutical was injected ID into the web space in hind legs of ten rabbits (200-600 microCi/0.05 ml). Scintigrams were taken at 10-min intervals up to 3 h in three rabbits. The injection site and the hind legs were massaged after injection in the other seven rabbits and scintigrams were taken at 10-min intervals up to 2 h. Blood samples were obtained at 5, 15, 30, 90 and 120 min in both groups. In addition a 180-min sample was also taken in the first group. At the end of the study the rabbits were killed and the popliteal lymph nodes and the organs were removed to be weighed and counted. Our results indicated a high concentration of radioactivity in the popliteal lymph nodes and massage at the injection site increased the average uptake of the popliteal lymph node from 1.12% +/- 0.77% to 4.28% +/- 1.57% at 3 and 2 h, respectively (P less than 0.001). In scintigrams the lymph channels and the nodes were very well visualised. The blood radioactivity levels were too low to present a background problem. With massage 30% of the injected dose was removed from the injection site in 2 h. We have shown that 99mTc-dextran is a good radiopharmaceutical for the visualisation of the lymph system and deserves further experimental and clinical studies.     

Scintigraphic detection of pulmonary aspergillosis in rabbits with a radiolabeled leukotriene b4 antagonist.

Radiolabeled chemotactic peptides have been studied for their applicability to the visualization of infectious and inflammatory foci. Because a radiolabeled leukotriene B4 (LTB4) antagonist allowed visualization of intramuscular E. coli abscesses in rabbits within a few hours after injection, we decided to test the imaging characteristics of this agent in a more clinically relevant model of pulmonary aspergillosis. The pharmacokinetics and imaging characteristics of the 111In-labeled LTB4 antagonist DPC11870 were studied in New Zealand White rabbits with experimental pulmonary aspergillosis infection. The imaging characteristics of 111In-DPC11870 were compared with those of 67Ga-citrate, a radiopharmaceutical commonly used to detect pulmonary infections in patients. METHODS: Pulmonary aspergillosis was induced in the left lung of rabbits by intratracheal inoculation of 1 x 10(8) conidia of Aspergillus fumigatus. Three days after the inoculation, the rabbits received 111In-DPC11870 or 67Ga-citrate intravenously. Images were acquired at several time points up to 24 h after injection. RESULTS: Pulmonary aspergillosis was visualized with both agents. Images acquired after injection of 111In-DPC11870 showed uptake in the pulmonary lesions from 6 h after injection. Because of accumulation at the site of infection and clearance from the background, the images improved with time. Region-of-interest analysis at 24 h after injection revealed infected lung-to-normal lung ratios of 5.0 +/- 1.5 for 111In-DPC11870 and 2.9 +/- 0.6 for 67Ga-citrate. CONCLUSION: The radiolabeled LTB4 antagonist DPC11870 clearly delineated experimentally induced pulmonary aspergillosis in rabbits. Images acquired at 24 h after injection of 111In-DPC11870 were superior to those obtained after injection of 67Ga-citrate.     

Phase I clinical study of 99mTc-ECD]

A phase I clinical study of 99mTc-L,L-ethyl cysteinate dimer (99mTc-ECD) was carried out in 3 normal volunteers. There was no significant change in vital signs and laboratory parameters attributing to the radiopharmaceutical. 99mTc-ECD was rapidly taken up by the brain, reaching the maximum peak activity within 1 min after the injection and remained relatively constant over several hours. The brain uptake of 99mTc-ECD at 5 min was 5.4 +/- 0.5% which decreased to 5.0 +/- 0.3% by 65 min. 99mTc-ECD cleared rapidly from other organs. The primary excretion route was through the kidneys. Cumulative 99mTc activity in the urine at 90 min and 24 hr were 60.2 +/- 7.3% and 88.5 +/- 10.3%, respectively. The critical organ was the bladder wall with an estimated radiation dose of 0.073 mGy/MBq, which was acceptable value. Clear SPECT images were obtained at 30, 90 and 150 min postinjection. In conclusion, 99mTc-ECD is a safe and promising radiopharmaceutical for the evaluation of regional cerebral blood flow.     

Diagnosis of venous leakage by 133Xe corporeal clearance after intracavernous injection of prostaglandin E1 in poorly responding patients.

133Xe corporeal clearance after intracavernous (IC) prostaglandin E1 (PGE-1) injection was assessed in detecting venous leakage (VL) in a group of impotent patients with poor clinical response to PGE-1 injection. 133Xe corporeal washouts were done in the flaccid state and at full erection or at 20 min after the IC injection of 20 micrograms PGE-1 in cases where no full erection occurred in sequence on two separate days. In each case, data were acquired in frame mode after intracorporeal injection on one side of the midline just behind the glans of 0.1 ml, namely, 1-2 mCi (34-74 MBq) 133Xe in saline for 20 min. A time-activity curve was generated from the region of interest (ROI) at the site of injection and a computer routine was used to calculate clearance half-time (T1/2) in min and flow rate (Q) in ml per 100 g tissue per min. The data of 20 patients with equivocal response to IC PGE-1 were analysed. Of them, 14 had venous leakage and six had no vascular impairment (NVI). Venous leakage was proved by Doppler analysis, cavernosography after PGE-1, and/or selective arteriography. Twelve of 14 patients with VL had enhanced 133Xe corporeal clearance after PGE-1 with a significant decrease in T1/2 (mean +/- S.D.) from 115.9 +/- 196.0 to 13.3 +/- 13.4 (P less than 0.05) and increase in Q from 2.1 +/- 2.2 to 7.5 +/- 5.6 (P less than 0.01). In contrast, all six patients with NVI had decreased 133Xe corporeal clearance.(ABSTRACT TRUNCATED AT 250 WORDS)     

99mTc-labelling of leucocytes with 99mTc-DPO: a complex developed for myocardial imaging

The lipophilic 99mTc-DPO complex, developed as a myocardial imaging radiopharmaceutical, was used to label leucocytes. After an incubation of 0.1 ml 99mTc-DPO (8 micrograms DMPE*2HCl) with mixed leucocytes in plasma, the labelling efficiency was over 70%. During incubation in 5 ml plasma, a loss of activity was found between 20% (1 h) and 35% (3 h) caused by elution. Disturbances of cell viability could not be found with the help of the chemiluminescence test. The in vivo recovery was determined in three dogs and was 45%-50% (0.5 h), 30%-36% (1 h), and 18%-24% (3 h). Autologous 99mTc-DPO-leucocytes were used on seven patients with suspected osteomyelitis, there were four true negative and three true positive results. The target/nontarget ratio determined by ROI in the positive cases was 1.8 to 2.5 at 3 h after injection.     

Initial experience with SPECT examinations using [123I]IBZM as a D2-dopamine receptor antagonist in Parkinson's disease.

[123I]IBZM is a new radioactive labelled ligand which has a high affinity and specificity to D2-dopamine receptors. The in vivo kinetics of [123I]IBZM were studied in patients with unilateral and bilateral accentuated idiopathic Parkinson's disease. The uptake in the basal ganglias and the imaging properties of this D2 receptor antagonist as a radiopharmaceutical for SPECT examinations had to be investigated. 5 patients, aged 42-66 years, (2 m/3 f) were examined. Each patient received 185 MBq [123I]IBZM intravenously. Blood samples were taken 0-120 min post injection (p.i.) and time activity curves were plotted. Three SPECT examinations were performed (I: 30-50 min; II: 50-70 min; and III: 70-90 min p.i.). The count rates (counts/pixel) in the basal ganglias and the cerebellum were measured for each SPECT series on transverse slices using the region-of-interest technique. The time-activity curve of [123I]IBZM shows a rapid decline in plasma during the first 10 min followed by a plateau until 120 min after injection. The SPECT examinations demonstrate the highest count rate in the basal ganglia during SPECT series III (i.e., 70-90 min p.i.). The side-to-side difference of the count rates were in the range of 3% in four patients, and 10% in one patient. The biokinetic data of [123I]IBZM make this substance capable as a radiopharmaceutical for SPECT examinations. The basal ganglia are best visualized 70-90 min p.i., thus [123I]IBZM seems to be a promising imaging agent for diseases of the D2-dopaminergic receptor system.     

99mTc-Methyl-CCNU for the static imaging of kidneys

A new radiopharmaceutical, ^99mTc-Methyl-CCNU, was prepared for the static imaging of kidneys, and the radiochemical purity was tested by paper and thin-layer chromatography. The biological distribution was studied in 15 mice sacrificed at 10 min, 30 min, 1 h, 3 h, and 6 h after IV injection. Blood clearance and excretion of the agent in urine were followed in three volunteers for a period of 24 h. Renal uptake was high (25% in 6 h), plasma clearance very fast (90% in 1 h), and urinary excretion reached a plateau after 6 h with 25% excretion. A longitudinal slice of a rabbit kidney showed the cortical accumulation on autoradiography and scintigraphy.Clinical studies indicated the usefulness of this radiopharmaceutical as a kidney imaging agent.     

CSF Flow Quantification of the Cerebral Aqueduct in Normal Volunteers Using Phase Contrast Cine MR Imaging

Objective

To evaluate whether the results of cerebrospinal fluid (CSF) flow quantification differ according to the anatomical location of the cerebral aqueduct that is used and the background baseline region that is selected.

Materials and Methods

The CSF hydrodynamics of eleven healthy volunteers (mean age = 29.6 years) were investigated on a 1.5T MRI system. Velocity maps were acquired perpendicular to the cerebral aqueduct at three different anatomical levels: the inlet, ampulla and pars posterior. The pulse sequence was a prospectively triggered cardiac-gated flow compensated gradient-echo technique. Region-of-interest (ROI) analysis was performed for the CSF hydrodynamics, including the peak systolic velocity and mean flow on the phase images. The selection of the background baseline regions was done based on measurements made in two different areas, namely the anterior midbrain and temporal lobe, for 10 subjects.

Results

The mean peak systolic velocities showed a tendency to increase from the superior to the inferior aqueduct, irrespective of the background baseline region, with the range being from 3.30 cm/sec to 4.08 cm/sec. However, these differences were not statistically significant. In the case of the mean flow, the highest mean value was observed at the mid-portion of the ampulla (0.03 cm³/sec) in conjunction with the baseline ROI at the anterior midbrain. However, no other differences were observed among the mean flows according to the location of the cerebral aqueduct or the baseline ROI.

Conclusion

We obtained a set of reference data of the CSF peak velocity and mean flow through the cerebral aqueduct in young healthy volunteers. Although the peak systolic velocity and mean flow of the CSF differed somewhat according to the level of the cerebral aqueduct at which the measurement was made, this difference was not statistically significant.     

A bivalent leukotriene B(4) antagonist for scintigraphic imaging of infectious foci.

Several radiolabeled chemotactic peptides have been tested for their suitability to show infection and inflammation. Leukotriene B(4) (LTB(4)) receptor-binding ligands could be useful agents for revealing neutrophilic infiltrations because the LTB(4) receptor is abundantly expressed on neutrophils after an inflammatory stimulus. In this study, we investigated the in vivo and in vitro characteristics of a new hydrophilic (111)In-labeled LTB(4) antagonist. METHODS: The LTB(4) antagonist DPC11870-11 was labeled with (111)In and intravenously injected into New Zealand White rabbits with Escherichia coli infection in the left thigh muscle. The pharmacokinetics and biodistribution were studied by serial scintigraphic imaging (0-24 h after injection) and by ex vivo counting of dissected tissues (6 and 24 h after injection). The receptor-mediated in vivo localization of the compound was investigated in 3 rabbits that received an excess of nonradioactive indium-labeled agent 2 min before the administration of the (111)In-labeled LTB(4) antagonist. RESULTS: In rabbits with intramuscular E. coli infection, the abscess was visualized as early as 2 h after injection. Accumulation in the abscess increased with time, resulting in excellent images at 6 h after injection. Blood clearance was rapid in the first hours after injection (alpha-half-life = 30 +/- 6 min, 85%; beta-half-life = 25.7 +/- 0.8 h, 15%). Abscess-to-background ratios, as derived from the region-of-interest analysis, increased to 34 +/- 7 at 24 h after injection. The images of both groups showed moderate uptake in the liver, spleen, kidneys, and bone marrow. No activity was seen in the bladder, indicating almost complete retention in the kidneys. The uptake in the abscess could be blocked completely by injection of an excess of nonradioactive agent, indicating a specific receptor-ligand interaction of the radiolabeled agent in the infected tissue. Biodistribution data showed that after saturation of the LTB(4) receptor, the abscess uptake, in percentage injected dose per gram, was significantly reduced (0.03 +/- 0.02 vs. 0.24 +/- 0.06, P = 0.008). CONCLUSION: The modified LTB(4) antagonist showed infectious foci rapidly after injection because of specific receptor-ligand interaction. Because of the high abscess-to-background ratios that were obtained and the fact that no accumulation of radioactivity was observed in the gastrointestinal tract, this compound has excellent characteristics for revealing infectious and inflammatory foci.     

Fourier analysis of cerebrospinal fluid flow velocities: MR imaging study. The Scandinavian Flow Group

An interleaved pseudocinematographic FLASH (fast low-angle shot) sequence with additional pulsed gradients for flow encoding was used to quantify cerebrospinal fluid (CSF) flow velocities and CSF production. Flow-dependent phase information was obtained by subtracting two differently encoded phase images. The phase information in the resultant image was converted to flow velocity with a calibration curve with the slope 26.5 radian.m-1.sec. The velocity versus time function was Fourier transformed and a continuous curve was fitted to the measured data with use of the first three harmonics. The in vivo measurements showed a significant variation in flow velocities in the cerebral aqueduct (range, 6-51 mm/sec). Calculated CSF production was in the range of 0.6-1.2 L/24 h. The present method gives valuable information about CSF hydrodynamics in an imaging time of less than 8 minutes.     

Detection of experimental atherosclerosis with indium-111 radiolabelled hematoporphyrin derivative

It has been observed that atherosclerotic lesions (AL) concentrate certain porphyrins. We evaluated the usefulness of 111In-labelled Photofrin II (PFII), a porphyrin derived from haematoporphyrin derivative, for detection of experimental AL in cholesterol fed rabbits. Three groups of rabbits were studied: non-atherosclerotic (n = 3), 6 and 12 week cholesterol fed (n = 4, 3). 111In-PFII was injected intravenously and gamma camera images were obtained at 24 and 48 h. At 48 h, explanted aortas were also imaged. Aortic arch (AA) to background (BKG) count ratios were calculated from images of the whole body and explanted aortas. AA/BKG ratios were significantly higher in the 12 week cholesterol fed rabbits (3.9 +/- 0.72 at 24 h) and (4.0 +/- 0.67 at 48 h) than in the non-atherosclerotic rabbits (2.2 +/- 0.07 at 24 h) and (2.3 +/- 0.18 at 48 h) (p less than 0.05). The AA/BKG ratio for the explanted aortas showed similar results. Additionally, in two of three 12 week cholesterol fed rabbits, focal count deposition was visible on the whole animal images at the site of aortic arch atherosclerosis. We conclude that 111In-PFII concentrates in AL as early as 24 h after injection and has the potential to be used as an imaging agent for experimental atherosclerosis.     

Evaluation of 99mTc-dextran as a lymphoscintigraphic agent in rabbits

Dextran (clinical grade, average mol. wt. 82,200) was labelled with ^99mTc and the labelling efficiency was checked by paper and thin-layer chromatography and electrophoresis. The amount of free ^99mTcO ₄ ^- was always less than 1%. The radiopharmaceutical was injected ID into the web space in hind legs of ten rabbits (200–600 Ci/0.05 ml). Scintigrams were taken at 10-min intervals up to 3 h in three rabbits. The injection site and the hind legs were massaged after injection in the other seven rabbits and scintigrams were taken at 10-min intervals up to 2 h. Blood samples were obtained at 5, 15, 30, 90 and 120 min in both groups. In addition a 180-min sample, was also taken in the first group. At the end of the study the rabbits were killed and the popliteal lymph nodes and the organs were removed to be weighed, and counted. Our results indicated a high concentration of radioactivity in the popliteal lymph nodes and massage at the injection site increased the average uptake of the popliteal lymph node from 1.12%±0.77% to 4.28%±1.57% at 3 and 2 h, respectively (P<0.001). In scintigrams the lymph channels and the nodes were very well visualised. The blood radioactivity levels were too low to present a background problem. With massage 30% of the injected dose was removed from the injection site in 2 h. We have shown that ^99mTc-dextran is a good radiopharmaceutical for the visualisation of the lymph system and deserves further experimental and clinical studies.     

Modified gait patterns due to cam FAI syndrome remain unchanged after surgery

BackgroundIn order to reduce the development of hip osteoarthritis related to cam-type femoroacetabular impingement syndrome (FAIS), corrective surgery has evolved to become a safe and effective treatment. Although corrective surgery produces high level of patient satisfaction, it is still unclear how it affects muscle and hip contact forces during level walking.Research questionThe purpose was to compare the muscle force contributions and hip contact forces in patients before and after surgical correction for cam FAIS with healthy control (CTRL) individuals during level walking.MethodsEleven male patients with symptomatic cam-type morphology, who underwent hip osteochondroplasty, had their level walking recorded pre- and at 2-year postoperatively. The patients were sex-, age-, BMI-matched to 11 CTRL individuals. Sagittal and frontal hip kinematics and kinetics were computed and, subsequently, muscle and hip contact forces were estimated using musculoskeletal modelling and static optimization.ResultsPatient-reported outcomes improved postoperatively. The pre- and postoperative FAIS walked slower and with shorter steps than the CTRL. Postoperative biceps femoris (CTRL: 0.35 ± 0.13 N/BW; pre-op: 0.28 ± 0.11 N/BW; post-op: 0.20 ± 0.07 N/BW) and semimembranosus forces (CTRL: 0.77 ± 0.24 N/BW; pre-op: 0.66 ± 0.24 N/BW; post-op: 0.41 ± 0.14 N/BW) were lower at ipsilateral foot-strike. Postoperative rectus femoris force (CTRL: 1.73 ± 0.35 N/BW; pre-op: 1.44 ± 0.24 N/BW; post-op: 1.18 ± 0.23 N/BW) was lower than the other two groups, and the pre- and postoperative FAIS had lower iliacus (CTRL: 1.17 ± 0.18 N/BW; pre-op: 0.93 ± 0.16 N/BW; post-op: 0.94 ± 0.21 N/BW) and psoas (CTRL: 1.55 ± 0.24 N/BW; pre-op: 1.14 ± 0.38 N/BW; post-op: 1.10 ± 0.46 N/BW) muscle forces at contralateral foot-strike compared with the CTRL. Pre- and postoperative FAIS demonstrated lower peak hip contact loading resultant than the CTRL.SignificanceThe altered gait parameters observed in the preoperative FAIS was not restored after surgery, and was still away from the CTRL. It is possible that the reduced dynamic muscle forces of the biceps femoris, semimembranosus and rectus femoris postoperatively were associated with the protected mechanism that involved the iliopsoas preoperatively. This is an indication that the gait adaptations affected by the FAIS do not restore to normal after surgical correction at the 2-years follow-up.     

Effect of hyperbaric oxygen on the blood: cerebrospinal fluid transfer of tobramycin

The blood:cerebrospinal fluid (CSF) transfer of the aminoglycoside antibiotic, tobramycin (TOB) was assessed in rabbits. The CSF:blood ratio of TOB, 90 min after a subcutaneous injection, was approximately 1:100 as measured by an agar disc diffusion bioassay. Hyperbaric oxygen therapy at a pressure of 3 ATA caused a slight, non-significant, increase in this ratio, while high dose carbon dioxide, a treatment known to damage the blood:brain barrier, more than doubled this ratio. Thus, hyperbaric oxygen has no significant effect on CSF concentration of TOB in rabbits with intact meninges.     

Experimental evaluation of watersoluble contrast media for myelography

Summary An experimental method for testing contrast media for myelography was developed and used to compare three watersoluble contrast media, iocarmate meglumine, iothalamate meglumine and metrizamide after suboccipital myelography in 120 rabbits. A further 71 rabbits served as controls. Iocarmate and iothalamate caused vigorous convulsions; metrizamide did not. Examination of the CSF revealed an acute pleocytosis after installation of the contrast media and after cisternal puncture with injection of hypertonic saline. Histological examination of the spinal cord, nerve roots and meninges revealed pathological changes in 1 of 32 unoperated controls (3%). Leucocyte infiltrations were found in the meninges, nerve roots and spinal cord of about 20% of the animals after myelography, after cisternal puncture without injection or with injection of hypertonic saline. There were no significant quantitative differences between the experimental groups. Degenerative changes were seen only after myelography. No meningeal fibrosis was demonstrated. An abnormal leucocyte count in the primary CSF influenced the incidence of histological changes, indicating that only rabbits with CSF cell counts within normal limits should be used in future experiments.