PSMA-1007 Uptake in Ganglia of the Sympathetic Trunk and Its Intra-individual Reproducibility.

AIM/PURPOSE: 18F-labeled PSMA ligands offer various advantages as PET tracers over 68Ga-labeled PSMA counterparts. Especially, an improved spatial resolution leads to improved detection rates of smaller prostate cancer (PCa) lesions. However, physiological PSMA uptake of ganglia of the sympathetic trunk can be quickly misinterpreted as possible PSMA-positive lymph node metastases. The aim of this retrospective study is to investigate [18F]PSMA-1007 uptake and its intra-individual reproducibility in ganglia of the sympathetic trunk. METHODS: We retrospectively included 28 consecutive patients (median age 69 ± 9 with a range of 49-90) with biochemical recurrence of PCa who underwent [18F]PSMA-1007 PET/CT scan and, accordingly, a follow-up examination between August 2018 and August 2021. Cervical, coeliac, and sacral ganglia were identified on the iterative PET reconstructions and correlated with CT component. Tracer uptake of ganglia was determined by measuring SUVmax and SUVmean values. Anatomical position of the ganglia in relation to adjacent vertebral bodies were noted. Statistical analyses were conducted using two-way repeated measures ANOVA and descriptive statistics. RESULTS: The highest [18F]PSMA-1007 uptake was found in coeliac ganglia followed by cervical and sacral ganglia. The SUVmax in coeliac ganglia was 3.13 ± 0.85 (follow-up scan 3.11 ± 0.93), in cervical ganglia 2.73 ± 0.69 (follow-up scan 2.67 ± 0.74), and in sacral ganglia 1.67 ± 0.50 (follow-up scan 1.64 ± 0.52). The SUVmean in coeliac ganglia was 2.28 ± 0.64 (follow-up scan 2.28 ± 0.66), in cervical ganglia 1.62 ± 0.43 (follow-up scan 1.61 ± 0.43) and in sacral ganglia 1.15 ± 0.33 (follow-up scan 1.12 ± 0.34). In a given ganglion station, there was no statistically significant difference of SUVmax or SUVmean values between baseline and follow-up scans. CONCLUSIONS: The first systematically described physiological [18F]PSMA-1007 uptake in ganglia of the sympathetic trunk showed a low variability of SUVmax or SUVmean and a good intra-individual reproducibility of [18F]PSMA-1007 uptake in follow-up scans. These findings might improve and guide the differentiation of ganglia from possible malignant lesions.

Evaluation of the novel myocardial perfusion positron-emission tomography tracer 18F-BMS-747158-02: comparison to 13N-ammonia and validation with microspheres in a pig model.

BACKGROUND: Positron-emission tomography (PET) tracers for myocardial perfusion are commonly labeled with short-lived isotopes that limit their widespread clinical use. 18F-BMS-747158-02 (18F-BMS) is a novel pyridaben derivative that was evaluated for assessment of myocardial perfusion by comparison with 13N-ammonia (13NH3) and with radioactive microspheres in a pig model. METHODS AND RESULTS: Fourteen pigs injected with 500 MBq of 13NH3 or 100 to 200 MBq of 18F-BMS underwent dynamic PET at rest and during pharmacological stress. In 8 of these pigs, 18F-BMS was injected during stress combined with transient, 2.5-minute constriction of the left anterior descending coronary artery. Radioactive microspheres were coinjected with 18F-BMS. Ratios of myocardial tracer uptake to surrounding tissues were determined, and myocardial blood flow was quantified by compartmental modeling. Both tracers showed high and homogeneous myocardial uptake. Compared with 13NH3, 18F-BMS showed higher activity ratios between myocardium and blood (rest 2.5 versus 4.1; stress 2.1 versus 5.8), liver (rest 1.2 versus 1.8; stress 0.7 versus 2.0), and lungs (rest 2.5 versus 4.2; stress 2.9 versus 6.4). Regional myocardial blood flow assessed with 18F-BMS PET showed good correlation (r=0.88, slope=0.84) and agreement (mean difference -0.10 [25th percentile -0.3, 75th percentile 0.1 mL x min(-1) x g(-1)]) with that measured with radioactive microspheres over a flow range from 0.1 to 3.0 mL x min(-1) x g(-1). The extent of defects induced by left anterior descending coronary artery constriction measured by 18F-BMS and microspheres also correlated closely (r=0.63, slope=1.1). CONCLUSIONS: 18F-BMS-747158-02 is a very attractive new PET perfusion tracer that allows quantitative assessment of regional myocardial perfusion over a wide flow range. The long half-life of 18F renders this tracer useful for clinical PET/CT applications in the workup of patients with suspected or proven coronary artery disease.

Transfluthrin Spatial Repellent on US Military Materials Reduces Culex tarsalis Incursion in a Desert Environment.

Standard residual pesticides applied to US military materials such as camouflage netting can reduce mosquito biting pressure in the field but may contribute to the evolution of resistance. However, residual applications of a spatial repellent such as transfluthrin could allow mosquitoes the opportunity to escape, only inducing mortality if insects linger, for example after becoming trapped in a treated tent. In this study we investigated the capability of transfluthrin on 2 types of US military material to reduce natural populations of disease vector mosquitoes in a cool-arid desert field environment in southern California. We found that transfluthrin could reduce Culex tarsalis incursion into protected areas by up to 100% upon initial treatment and up to 45% for at least 16 days posttreatment, showing that this compound could be an effective element in the US Department of Defense integrated vector management system appropriate for further study.

Lipoprotein(a) in patients initiating antiretroviral therapy.

OBJECTIVES: The interaction between lipoprotein(a), an emerging cardiovascular risk factor, and antiretrovirals (ARVs) has been less well studied than the interaction between either cholesterol or triglycerides and these drugs. In this study we assessed the effect of initiating antiretroviral therapy (ART) on lipoprotein(a) levels. METHODS: Fasting samples from 95 patients initiating ART with nucleoside/nucleotide reverse transcriptase inhibitors plus nonnucleoside reverse transcriptase inhibitors or protease inhibitors were obtained. Lipids and lipoproteins were determined until week 48. RESULTS: As in the general population, the study population showed a highly skewed lipoprotein(a) distribution (median 9.9 mg/dL, range 0.1-110 mg/dL). The study population was divided into individuals with lipoprotein(a) >or=30 mg/dL at baseline (n=28) and those with <30 mg/dL (n=67). Almost exclusively, patients with high lipoprotein(a) at baseline (median 51.6 mg/dL) showed a profound increase of median 26.7 mg/dL (week 24). This effect was not associated with specific ARVs and was independent of changes in other lipids. The low-lipoprotein(a) group (baseline median 7 mg/dL) showed a small increase of median 2.6 mg/dL (week 24). CONCLUSIONS: Marked increases in lipoprotein(a) after initiation of ART were mainly restricted to patients with high baseline levels. This may have clinical implications as patients with high lipoprotein(a) are at higher risk for myocardial infarction and stroke.

Fetal spina bifida repair--current trends and prospects of intrauterine neurosurgery.

Myelomeningocele is a common dysraphic defect leading to severe impairment throughout the patient's lifetime. Although surgical closure of this anomaly is usually performed in the early postnatal period, an estimated 330 cases of intrauterine repair have been performed in a few specialized centers worldwide. It was hoped prenatal intervention would improve the prognosis of affected patients, and preliminary findings suggest a reduced incidence of shunt-dependent hydrocephalus, as well as an improvement in hindbrain herniation. However, the expectations for improved neurological outcome have not been fulfilled and not all patients benefit from fetal surgery in the same way. Therefore, a multicenter randomized controlled trial was initiated in the USA to compare intrauterine with conventional postnatal care, in order to establish the procedure-related benefits and risks. The primary study endpoints include the need for shunt at 1 year of age, and fetal and infant mortality. No data from the trial will be published before the final analysis has been completed in 2008, and until then, the number of centers offering intrauterine MMC repair in the USA is limited to 3 in order to prevent the uncontrolled proliferation of new centers offering this procedure. In future, refined, risk-reduced surgical techniques and new treatment options for preterm labor and preterm rupture of the membranes are likely to reduce associated maternal and fetal risks and improve outcome, but further research will be needed.

Analysis of cerebrospinal fluid in healthy rabbits and rabbits with clinically suspected encephalitozoonosis.

Samples of uncontaminated cerebrospinal fluid (csf) were collected from the cisterna magna of 20 healthy laboratory rabbits and 21 pet rabbits with vestibular disease and/or paresis due to clinically suspected encephalitozoonosis. In the healthy rabbits' csf the leucocyte count was

Transgastric in vivo histology in the peritoneal cavity using miniprobe-based confocal fluorescence microscopy in an acute porcine model.

BACKGROUND AND STUDY AIMS: Natural orifice transluminal endoscopic surgery (NOTES) is an emerging technology. Apart from its therapeutic implications, this type of access to the peritoneal cavity might also be useful for targeted in vivo histological investigation by means of confocal fluorescence microscopy. In this study we therefore aimed to assess the feasibility of miniprobe-based confocal fluorescence microscopy during transgastric endoscopy in an acute porcine model. MATERIALS AND METHODS: Transgastric in vivo histology was performed in five pigs, under general anesthesia. After incision of the anterior gastric wall, a double-channel video gastroscope was advanced into the peritoneal cavity. A flexible confocal miniprobe was introduced through the instrument channel of the endoscope after intravenous injection of 10 mL of fluorescein 1% in four of the pigs and of 50 mL of fluorescein isothiocyanate-dextran 150 000 4% in the fifth pig. The tip of the miniprobe was then placed on the peritoneal layer, the liver, and the spleen for confocal laser microscopy. RESULTS: Probes were easily attached to the peritoneal layer, the liver, and the spleen under direct visualization with the endoscope. Dynamic microscopic images of these organs were obtained with a frame rate of 12 frames per second. The flow of erythrocytes through blood vessels could be seen. The microstructural components of organs, such as lobules of the liver, were also easily identified. CONCLUSIONS: In vivo histology in the peritoneal cavity is feasible during NOTES and this technique combines the minimally invasive approach to the intraperitoneal organs afforded by NOTES and real-time, in vivo acquisition of dynamic histological images.

Changes in intra-abdominal pressure, hemodynamics, and peak inspiratory pressure during gastroscopy in a porcine model.

BACKGROUND AND STUDY AIMS: The aim of this experimental study was to assess the effect of gastric insufflation on intra-abdominal pressure (IAP) and associated hemodynamic and respiratory changes during upper gastrointestinal endoscopy. METHODS: Measurements were taken from pigs under general anesthesia with controlled ventilation. Gastroscopy was carried out with continuous insufflation of air by a standard endoscopic light source/insufflator. The cardiac index and global end-diastolic volume index (GEDVI; reflecting preload) were measured by transpulmonary thermodilution. IAP, heart rate, mean arterial pressure (MAP), central venous pressure, systemic vascular resistance index (SVRI; reflecting afterload), peak inspiratory pressure (PIP), and oxygenation (SaO (2)) were also recorded. RESULTS: A total of 266 paired measurements (at the time of transpulmonary thermodilution) were taken from 14 animals. During air insufflation, we observed a significant rise in IAP in all animals up to intermittent values of 22 mm Hg. IAP and PIP correlated well (r = 0.666, P < 0.001), with the latter reaching values as high as 45 mbar in one pig, leading to respiratory compromise. Only marginal changes in heart rate, and a continuous, almost significant rise in MAP (due to a significant increase in SVRI) were recorded. We observed a slight increase in GEDVI, predominantly during the initial phase of air insufflation. The cardiac index showed no substantial changes. There were no episodes of hemodynamic instability, nor a decline in SaO (2). CONCLUSIONS: Air insufflation during gastroscopy resulted in a significant increase in IAP. The main clinically relevant finding was a steady increase in SVRI. Major increments in PIP suggest a role of intra-abdominal hypertension in otherwise unexplained respiratory compromise during upper gastrointestinal endoscopy.

Effect of pneumoperitoneum on hemodynamics and inspiratory pressures during natural orifice transluminal endoscopic surgery (NOTES): an experimental, controlled study in an acute porcine model.

BACKGROUND AND STUDY AIM: Physiologic reactions during natural orifice transluminal endoscopic surgery (NOTES) may differ from those at laparoscopy. This experimental study assessed the effect of pneumoperitoneum induced by endoscope air pump on hemodynamics and inspiratory pressures during transgastric peritoneoscopy. METHODS: Transgastric peritoneoscopy was performed in 11 female pigs (35 - 50 kg) under general anesthesia. Five pigs with controlled insufflation and no endoscopic intervention served as controls. Cardiac index and global end-diastolic volume index (GEDVI; reflecting preload) were measured every 3 minutes by transpulmonary thermodilution. We also recorded: intra-abdominal pressure (IAP), heart rate, mean arterial pressure (MAP), systemic vascular resistance index (SVRI; reflecting afterload), peak inspiratory pressure (PIP), and oxygenation. RESULTS: One study group pig was excluded from analysis because of a major complication related to the gastric incision. In the remaining 15 animals we performed 264 paired measurements. On-demand insufflation in the study group produced wide variation in intra-abdominal pressures; the control group demonstrated minimal fluctuation around a predetermined value. In the study group, IAP and PIP correlated well ( R = 0.667, P = 0.000), with maximum PIP values of 40 mbar contrasting with the control group maximum of 26.5 mbar. Hemodynamically, there was a minor decrease of cardiac index in the study group (in contrast to the control group). Relative changes in cardiac index and IAP during transgastric peritoneoscopy correlated highly significantly ( R = - 0.416, P = 0.000). Neither group showed hemodynamic instability or decline in oxygen saturation. CONCLUSIONS: On-demand insufflation with a standard endoscopic light source/insufflator resulted in a marked median increase and wide variation in IAP throughout transgastric peritoneoscopy. Hemodynamic changes were moderate. However, major increases in PIP suggest a need for stricter control of intra-abdominal hypertension during NOTES.

Macroscopic phase separation of superconductivity and ferromagnetism in Sr0.5Ce0.5FBiS2-x Se x revealed by µSR.

The compound Sr0.5Ce0.5FBiS2 belongs to the intensively studied family of layered BiS2 superconductors. It attracts special attention because superconductivity at T sc = 2.8 K was found to coexist with local-moment ferromagnetic order with a Curie temperature T C = 7.5 K. Recently it was reported that upon replacing S by Se T C drops and ferromagnetism becomes of an itinerant nature. At the same time T sc increases and it was argued superconductivity coexists with itinerant ferromagnetism. Here we report a muon spin rotation and relaxation study (µSR) conducted to investigate the coexistence of superconductivity and ferromagnetic order in Sr0.5Ce0.5FBiS2-x Se x with x = 0.5 and 1.0. By inspecting the muon asymmetry function we find that both phases do not coexist on the microscopic scale, but occupy different sample volumes. For x = 0.5 and x = 1.0 we find a ferromagnetic volume fraction of ~8 % and ~30 % at T = 0.25 K, well below T C = 3.4 K and T C = 3.3 K, respectively. For x = 1.0 (T sc = 2.9 K) the superconducting phase occupies most (~64 %) of the remaining sample volume, as shown by transverse field experiments that probe the Gaussian damping due to the vortex lattice. We conclude ferromagnetism and superconductivity are macroscopically phase separated.

Computer-aided learning: experiences, perspectives and promises.

Despite the recent strong interest in computer-aided learning, very few high quality programs are available. This article describes an authoring system that was designed to help faculty at medical schools develop a library of effective computer-based lessons. Features of the system include ease of authoring and the ability to incorporate natural language input by the learner, model complex situations, keep track of 100 performance variables and employ interactive laser video disk technology. The authors describe the experience that has been gained in the development and implementation of computer-aided learning at a medical school, and reflect on its future applications and value.

Large-scale analysis of the Alu Ya5 and Yb8 subfamilies and their contribution to human genomic diversity.

We have utilized computational biology to screen GenBank for the presence of recently integrated Ya5 and Yb8 Alu family members. Our analysis identified 2640 Ya5 Alu family members and 1852 Yb8 Alu family members from the draft sequence of the human genome. We selected a set of 475 of these elements for detailed analyses. Analysis of the DNA sequences from the individual Alu elements revealed a low level of random mutations within both subfamilies consistent with the recent origin of these elements within the human genome. Polymerase chain reaction assays were used to determine the phylogenetic distribution and human genomic variation associated with each Alu repeat. Over 99 % of the Ya5 and Yb8 Alu family members were restricted to the human genome and absent from orthologous positions within the genomes of several non-human primates, confirming the recent origin of these Alu subfamilies in the human genome. Approximately 1 % of the analyzed Ya5 and Yb8 Alu family members had integrated into previously undefined repeated regions of the human genome. Analysis of mosaic Yb8 elements suggests gene conversion played an important role in generating sequence diversity among these elements. Of the 475 evaluated elements, a total of 106 of the Ya5 and Yb8 Alu family members were polymorphic for insertion presence/absence within the genomes of a diverse array of human populations. The newly identified Alu insertion polymorphisms will be useful tools for the study of human genomic diversity.

[Evaluation of perfusion in skin flaps by laser-induced indocyanine green fluorescence]. / Evaluation der Perfusion von Lappenplastiken mittels Laserfluoreszenz von Indocyaningrün.

Prediction of necrosis in critically perfused skin flaps is difficult and rarely precise. An early detection of insufficiently perfused skin is highly desirable since it may lead to surgical decisions such as operative flap revision or early resection. The application of laser-induced indocyanine green (ICG) fluoroscopy allows an objective quantification of skin perfusion and a high topographical resolution. Aim of the present study is to determine a threshold value for flap perfusion under well-defined experimental conditions and test the validity of the results in the clinical application. Twenty overdimensioned random pattern flaps with a length to width ratio of 4 : 1 (8 x 2 cm) were dissected at the anterior abdominal wall of 20 male Sprague-Dawley rats weighing 365 g on average. ICG fluorescence was performed at the end of the operation by intravenous injection of 1 g ICG/kg bodyweight into a tail vein and digital recording. On the seventh postoperative day, both the necrotic and surviving areas of the flaps were measured and the ICG-fluorescence was analysed in the areas that had undergone necrosis. 41 flaps with areas of critical perfusion (18 skin flaps, 13 muscle flaps, 8 replantations) were analysed in 39 patients. The surviving part of the flap had a mean perfusion index of 62 % compared to reference skin. The distal parts of the flap that necrotized during the experiment showed an average perfusion index of 19 % postoperatively. Differences were statistically significant (p < 0.001). In clinical application, a number of 13 flaps were found to have a perfusion index less than 25 % in a region of critical perfusion. Eleven of these developed a partial necrosis in that region, one flap underwent total necrosis. Indocyanine green fluoroscopy allows a detailed topographical analysis of flap perfusion and the prediction of necrosis. Experimental findings presented a threshold value for the perfusion index of 25 % which could be confirmed in clinical application.

A reliable method for localizing deep intracranial sources of the EEG.

We have demonstrated the reliability of a noninvasive method for successfully localizing the intracranial origin of the EEG. The dipole localization method (DLM) is a computer-assisted, mathematical method based on electrical field theory and is similar to localization methods currently used by electrocardiologists. In 12 patients with intractable epilepsy who were being evaluated for surgery, a known current source was introduced between two adjacent depth electrodes. Using scalp-recorded EEG only, DLM accurately and reliably localized the source to within 2 cm of the known origin in all instances where a discrete source was present. We conclude that DLM is a valid and reliable noninvasive method for localizing the intracranial source of some scalp-recorded EEG potentials, and that in some patients, use of this method may obviate the need for depth electrode implantation.

Population genetic data determined for five different single locus minisatellite probes.

We report on the population genetic data (frequencies of restriction fragments, heterozygosity rates, and mutation rates) obtained by analysis of approximately 1100 Hinfl-digested DNAs from West Germans. Probe G3 detects a common 1.7 kb DNA fragment showing a population frequency of about 13%. All the other fragments detected with probes MS1, MS31, MS43, G3 and YNH24 show frequencies of less than 8%. These data suggest that single locus DNA probes can provide valuable information for parentage evaluation and individualization.

The Marks Asthma Quality of Life Questionnaire: further validation and examination of responsiveness to change.

We performed analyses to examine the structure, validity, and responsiveness to change of the Marks Asthma Quality of Life Questionnaire (AQLQ), originally validated in Australia in a self-administered format, among 539 U.S. subjects with asthma. Subjects were interviewed twice by telephone over an 18-month period. Based on factor analyses, the subscale structure of the AQLQ was modified slightly to eliminate item overlap among subscale scores. Cross-sectionally, total AQLQ scores were significantly correlated in expected directions with baseline asthma severity scores (r = 0.58), SF-36 physical (r = -0.66) and mental (r = -0.40) health status scores, and pulmonary function (FEV1% predicted, r = -0.14). Longitudinally, changes in AQLQ total and subscale scores were significantly (P<0.01) associated with changes in asthma severity and both physical and mental status. The AQLQ, administered by telephone, appears to be useful for assessing changes in the impact of adult asthma.

Persistent increases of BAL neutrophils as a predictor of mortality following lung transplant.

STUDY OBJECTIVES: To evaluate whether findings from surveillance bronchoscopy predict survival following lung transplantation. DESIGN: Retrospective review and analysis of 498 bronchoscopies with transbronchial biopsy (TBB) and BAL performed in 34 patients after lung transplantation. SETTING: University-based, tertiary referral medical center. PATIENTS: Thirty-four patients after lung transplantation. The mean age at transplantation was 49+/-9 years; 20 (59%) were female. Twenty-four (71%) underwent single and 10 (29%) underwent bilateral lung transplantation. The most common pretransplantation diagnostic groups were emphysema/COPD without concomitant alpha1-antiprotease deficiency (n = 13) and other obstructive disease processes (n = 10). INTERVENTIONS: Over follow-up, subjects underwent multiple bronchoscopies with TBB and BAL. The median number per subject was 15 (25 to 75% range 13 to 17). MEASUREMENTS AND RESULTS: We calculated the overall median BAL WBCs and median percent neutrophils (polymorphonuclear leukocytes [PMNs]) among all of the BALs performed for each subject. We then calculated the mean +/- SD of those median values. We used Cox proportionate hazards to assess mortality risk. The median overall follow-up observation period for the cohort was 560 days. There were 11 deaths during this period. Twenty-four subjects (71%) had acute rejection (AR) grades 2 to 4 (mild to severe), and nine (27%) had obliterative bronchiolitis (OB) diagnosed by TBB at any point. The mean value for BAL WBCs was 366+/-145 x 10(3) per milliliter; for percentage PMNs, the mean was 7+/-10%. Adjusting for age, gender, single vs bilateral lung transplantation, pretransplantation diagnostic group, presence of AR, presence of OB, BAL WBC concentration, and lymphocyte CD4/CD8 ratio, PMN percent was a significant predictor of mortality (p = 0.02). CONCLUSIONS: Ongoing inflammation manifested by an increased percentage PMNs over repeated bronchoscopies predicts mortality following lung transplantation. Biopsy data alone may be insufficient to identify posttransplantation patients at risk of poor outcome.

Early diagnosis of spina bifida: the value of cranial ultrasound markers.

Ultrasonography plays an integral part in the prenatal diagnosis of neural tube defects. However, experienced sonographers with careful evaluation are successful in accurately diagnosing spina bifida only 80-90% of the time. This study was conducted to evaluate the accuracy and reliability of certain cranial ultrasound markers--the "lemon sign," cerebellar abnormalities, microcephaly, and ventriculomegaly--in facilitating the diagnosis of spina bifida in patients referred for prenatal diagnosis. Open spina bifida was diagnosed in 24 of 44 fetuses found to have neural tube defects. The lemon sign and cerebellar abnormalities were identified in all 16 fetuses in whom the diagnosis of spina bifida was made between 16-24 weeks' gestation. In four of these fetuses, the lemon sign and cerebellar abnormalities were noted 1-2 weeks before the spinal defect was identified. Microcephaly was present in 69% and ventriculomegaly in 63% of the cases. In the eight cases diagnosed after 24 weeks' gestation, the lemon sign was less reliable, being noted in only 25% of the fetuses. Ventriculomegaly increased in frequency to 75% and cerebellar abnormalities and microcephaly were present in all. Our findings indicate that these cranial ultrasound markers are extremely reliable for the early diagnosis of spina bifida; their identification should alert ultrasonographers at all skill levels to the possibility of open spina bifida.

Immobilization hypercalcemia crisis.

Profound hypercalcemia associated with immobilization is rare. Hypercalcemic crisis occurring as a result of immobilization in which there was not a coexisting, contributing medical condition has not, to our knowledge, been reported previously. Failure to consider hypercalcemia as the source of progressive anorexia, nausea, vomiting, and irritability resulted in a respiratory arrest and nearly fatal outcome in the case of a 13-year-old boy one month after a simple femoral fracture. Therapy consisting of the intravenous administration of fluids and corticosteroids was successful in lowering the serum calcium level until mobilization could be accomplished. Review of previously reported cases emphasizes the difficulty in recognition and diagnosis of this unusual condition. Surgeons treating patients with fractures should be aware of this complication and familiar with its appropriate therapy.

The differential effects of plasma from two groups of clinically similar schizophrenic patients on learning behavior in rats.

The effects of plasma from normal subjects and chronic schizophrenic patients were determined on the rate of learning a pole jump response in rats. The animals were trained to a buzzer CS and electroshock US. Mean trials to a 90 per cent avoidance criterion were determined using a 100 trial cut off. Plasma and other control solutions were given intraperitoneally in the morning and the procedure repeated in the afternoon with separate groups of rats. Test trials were initiated five minutes after injection. It was found that all plasma, in contrast to saline, produced an increase in the number of trials to learn the avoidance response. No difference in behavioral effects was noted comparing the plasma of all chronic schizophrenics to normals. However, within the chronic schizophrenic population there are subgroups whose plasma was differentially effective in reducing rate of learning. These results are preliminary and subject to continued experimentation. They are presented here to make others aware of the needto consider the existence of possible biologic subgroupings of schizophrenia in future investigations of the plasma-behavior interaction.