Vortex-assisted resin y90 delivery via 175 cm Truselect microcatheter: case factors for high residual despite double-flush protocol

PURPOSE

To report efficiency of resin y90 delivery using SIROS via 175 cm TruSelect microcatheter with double-flush protocol (40 ml dextrose total).

METHODS

IRB-approved retrospective review of all patients undergoing SIROS injection of y90 Sir-Spheres via TruSelect from 2019 through 2022 at one quaternary-care academic institution, including medical records.

RESULTS

Included were 48 infusions in 25 patients across 11 cancer histologies. Mean planned, delivered, and residual activities were 28 ± 17, 27 ± 17, 1.1 ± 0.56 mCi respectively (mean residual 4.9% ± 2.8%) across flex-dosing precalibrations including 1-day, 2-day, and 3-day SIROS (4/51, 16/51, and 28/51). Mean liver treatment volume was 483 ± 306 ml with target dose mean of 128 ± 26 Gy in non-segmentectomy cases; Radiation segmentectomy was performed in 15/48 (31%). Arterial stasis was documented in 9/48 (19%) of cases. Use of a 3-day precalibrated SIROS dose, use of activity <10 mCi, treatment of smaller liver volumes (<200 ml) and documentation of stasis were associated with higher residual activity ( P  = 0.025, P  = 0.0007, P  = 0.0177, and P  = 0.049, respectively) were associated with higher residuals.

CONCLUSION

Combining the new technologies of SIROS and the Truselect microcatheter with a double-flush protocol yielded <10% residual in 94% of y90 infusions. Future studies may clarify if the predictors of high residual dose seen here may warrant microcatheter-specific considerations for dosimetry or dose preparation at the Radiopharmacy level.

Pre-existing Hepatic Encephalopathy: Really a Contraindication to Elective TIPS?

PURPOSE

To evaluate the impact of pre-transjugular intrahepatic portosystemic shunt (TIPS) hepatic encephalopathy (HE) on developing post-TIPS HE.

MATERIALS AND METHODS

In this retrospective, single center observational study, all patients who underwent successful TIPS placement between January 2005 and May 2020 with data pertaining to HE in their chart were included. Patient demographics and procedural details were recorded. Clinical outcomes post-TIPS, were collected and compared across patients with and without pre-TIPS HE.

RESULTS

Of 326 included patients, 159 (159/326, 48.8%) had a history of pre-TIPS HE. In total those without a history of HE were more likely to develop HE during follow up (136 (136/167, 81.4%) vs 107 (107/159, 67.3%), p = 0.001). When evaluating for predictors of developing HE within 3 months of TIPS placement, no significant variables were found on logistic regression, including prior history of HE (HR 1.16 (95% CI 0.73-1.84), p = 0.529). Univariate and multivariate regression analysis, however, showed that a history of HE was predictive of developing HE at any point in the follow-up period (p = 0.002 and p = 0.008, respectively). However, on Kaplan-Meier analysis no significant difference in the development of HE (p = 0.574) or hospital admission for HE (p = 0.554) post-TIPS was seen between patients with and without pre-TIPS HE. Additionally, there was no difference in 3-month survival (p = 0.412) or overall survival post-TIPS survival (p = 0.798).

CONCLUSION

Pre-TIPS HE did not predict the development of HE within 3 months of TIPS. Outcomes such as hospital admission and survivability were not different between patients with and without prior HE.

Measurement of the Tumor-to-Normal Ratio for Radioembolization of Hepatocellular Carcinoma: A Prospective Study Comparing 2-Dimensional Perfusion Angiography, Technetium-99m Macroaggregated Albumin, and Yttrium-90 SPECT/CT

PURPOSE

To calculate the preradioembolic tumor-to-normal (T:N) ratio in hepatocellular carcinoma (HCC) using 2-dimensional (2D) perfusion angiography and compare it with that calculated using technetium-99m macroaggregated albumin (99mTc MAA) single-photon emission computed tomography (SPECT)/computed tomography (CT).

MATERIALS AND METHODS

This prospective single-arm study enrolled 15 participants with HCC who underwent 2D perfusion angiography immediately before the enrollment and with the microcatheter located at the same location as 99mTc MAA injection, after which SPECT/CT was performed. Quantitative digital subtraction angiography was used to calculate the area under the curve for the tumor and normal hepatic parenchyma and subsequently calculate the T:N ratio. The T:N ratio was calculated from the 99mTc MAA SPECT/CT and post-yttrium-90 bremsstrahlung SPECT/CT using dosimetry software.

RESULTS

The mean participant age was 64.1 years ± 9.8, and the study included 14 (93%) men and 1 (7%) woman. The mean tumor size was 4.1 cm (SD ± 2.4), and all participants received segmental treatments with glass microspheres. The mean T:N ratio calculated by 99mTc MAA SPECT/CT was 2.28 (SD ± 0.89) vs 2.25 (SD ± 0.99) calculated by 2D perfusion angiography (P = .45). For the 13 participants who underwent selective internal radiation therapy (transarterial radioembolization), there was no significant difference between the T:N ratios calculated by 2D perfusion angiography and post-90Y SPECT/CT (2.25 [SD ± 1.05] vs 1.91 [SD ± 0.39]; P = .12).

CONCLUSIONS

The T:N ratio calculated by 2D perfusion angiography correlated well with that calculated by 99mTc MAA SPECT/CT.

Cutaneous seeding of transitional cell carcinoma of the urinary bladder after placement of a subcutaneous ureteral bypass device in a dog with bilateral ureteral obstruction

CASE DESCRIPTION

A 12-year-old spayed female Jack Russell Terrier was presented with pollakiuria and stranguria.

CLINICAL FINDINGS

Transitional cell carcinoma (TCC) of the urinary bladder trigone and urethra was diagnosed via CT, cystoscopic, and histologic examinations. Azotemia developed 2 weeks following diagnosis, secondary to bilateral ureteral obstruction.

TREATMENT AND OUTCOME

Percutaneous antegrade ureteral stenting was unsuccessful; therefore, a subcutaneous ureteral bypass (SUB) device with 2 nephrostomy and 1 cystostomy catheters was surgically placed. Two months following placement of the SUB device, the dog developed a firm, multilobulated cutaneous mass at the site of the subcutaneous access port of the SUB device. Results of cytologic examination of cells aspirated from the mass were consistent with TCC. Within 1 month of confirmation of TCC of the cutaneous mass, the mass was ulcerated and infected, and the dog was euthanized because of signs of pain and perceived poor quality of life.

CLINICAL RELEVANCE

Seeding of neoplastic cells is a known complication of needle aspiration or biopsy or surgery in people and dogs with carcinomas. The occurrence of TCC at the SUB port site suggested caution with the placement of a SUB device in dogs with obstructive TCC.

Percutaneous transhepatic cholecystostomy drainage in a dog with extrahepatic biliary obstruction secondary to pancreatitis

CASE DESCRIPTION

An 8-year-old 36.3-kg (79.9-lb) spayed female Rottweiler was evaluated because of anorexia and vomiting.

CLINICAL FINDINGS

Extrahepatic biliary obstruction (EHBO) secondary to pancreatitis was suspected on the basis of results from serum biochemical analyses, CT, and cytologic examination.

TREATMENT AND OUTCOME

Only marginal improvement was observed after 24 hours of traditional medical management; therefore, novel continual biliary drainage was achieved with ultrasonographically and fluoroscopically guided placement of a percutaneous transhepatic cholecystostomy drainage (PCD) catheter. Within 24 hours after PCD catheter placement, the dog was eating regularly, had increased intestinal peristaltic sounds on abdominal auscultation, no longer required nasogastric tube feeding, and had decreased serum total bilirubin concentration (7.7 mg/dL, compared with 23.1 mg/dL preoperatively). Bile recycling was performed by administering the drained bile back to the patient through a nasogastric tube. The PCD remained in place for 5 weeks and was successfully removed after follow-up cholangiography confirmed bile duct patency.

CLINICAL RELEVANCE

Transhepatic PCD catheter placement provided fast resolution of EHBO secondary to pancreatitis in the dog of the present report. We believe that this minimally invasive, interventional procedure has the potential to decrease morbidity and death in select patients, compared with traditional surgical options, and that additional research is warranted regarding clinical use, safety, and long-term results of this procedure in veterinary patients, particularly those that have transient causes of EHBO, are too unstable to undergo more invasive biliary diversion techniques, or have biliary diseases that could benefit from palliation alone.

An Objective Study of Anatomic Shifts in Intracranial Hypotension Using Four Anatomic Planes

PURPOSE

Intracranial hypotension (IH) often remains undetected using current MR diagnostic criteria. This project aims to demonstrate that central incisural herniation is highly effective in helping to make this diagnosis.

MATERIALS AND METHODS

Magnetic resonance imaging (MRI) was analyzed in 200 normal and 81 clinically known IH patients. MRI reference lines approximating the plane of the incisura, the plane of the diaphragma sella, the plane of the foramen magnum, and the plane of the visual pathway were utilized to measure the position of selected brain structures relative to these reference lines.

RESULTS

All IH patients had highly statistically significant (p < 0.0001) measurable evidence of downward central incisural herniation when compared to normal controls. The first of the important observations was a downward shift of the mammillary bodies, which shortened the midsagittal width of the interpeduncular fossa cistern. A concurrent downward shift and deformity of the tuber cinereum accompanied the mammillary body shift. The second essential observation was an abnormal clockwise rotation of the long axis of the visual pathway. A severity grading system is proposed based on the extent of these shifts as well as secondary shifts of the brain stem, splenium, and cerebellar tonsils.

CONCLUSION

This study objectively delineates the anatomic shifts of brain structures adjacent to the incisura and foramen magnum. This methodology is sufficient to recognize the features of IH and to stratify the spectrum of IH findings into a functional grading system for quantifying the results of interventional therapy.

Irreversible electroporation and the pancreas: What we know and where we are going?

Pancreatic adenocarcinoma continues to have a poor prognosis with 1 and 5 years survival rates of 27% and 6% respectively. The gold standard of treatment is resection, however, only approximately 10% of patients present with resectable disease. Approximately 40% of patients present with disease that is too locally advanced to resect. There is great interest in improving outcomes in this patient population and ablation techniques have been investigated as a potential solution. Unfortunately early investigations into thermal ablation techniques, particularly radiofrequency ablation, resulted in unacceptably high morbidity rates. Irreversible electroporation (IRE) has been introduced and is promising as it does not rely on thermal energy and has shown an ability to leave structural cells such as blood vessels and bile ducts intact during animal studies. IRE also does not suffer from heat sink effect, a concern given the large number of blood vessels surrounding the pancreas. IRE showed significant promise during preclinical animal trials and as such has moved on to clinical testing. There are as of yet only a few studies which look at the applications of IRE within humans in the setting of pancreatic adenocarcinoma. This paper reviews the basic principles, techniques, and current clinical data available on IRE.

An integrative computational model for intestinal tissue renewal

OBJECTIVES

The luminal surface of the gut is lined with a monolayer of epithelial cells that acts as a nutrient absorptive engine and protective barrier. To maintain its integrity and functionality, the epithelium is renewed every few days. Theoretical models are powerful tools that can be used to test hypotheses concerning the regulation of this renewal process, to investigate how its dysfunction can lead to loss of homeostasis and neoplasia, and to identify potential therapeutic interventions. Here we propose a new multiscale model for crypt dynamics that links phenomena occurring at the subcellular, cellular and tissue levels of organisation.

METHODS

At the subcellular level, deterministic models characterise molecular networks, such as cell-cycle control and Wnt signalling. The output of these models determines the behaviour of each epithelial cell in response to intra-, inter- and extracellular cues. The modular nature of the model enables us to easily modify individual assumptions and analyse their effects on the system as a whole.

RESULTS

We perform virtual microdissection and labelling-index experiments, evaluate the impact of various model extensions, obtain new insight into clonal expansion in the crypt, and compare our predictions with recent mitochondrial DNA mutation data.

CONCLUSIONS

We demonstrate that relaxing the assumption that stem-cell positions are fixed enables clonal expansion and niche succession to occur. We also predict that the presence of extracellular factors near the base of the crypt alone suffices to explain the observed spatial variation in nuclear beta-catenin levels along the crypt axis.

Erratum: ZnO-based MIS photodetectors

[This corrects the article DOI: 10.1016/j.sna.2007.06.006.].

The parturient with coronary heart disease

Cardiac disease is one of the leading indirect causes of maternal mortality in the UK, exceeding numbers of direct deaths from thromboembolism and hypertension combined. Over one year in our unit we managed six women with coronary heart disease. In this series five women had stable coronary heart disease. Three delivered electively by caesarean section under combined spinal-epidural anaesthesia, a further two women had spontaneous vaginal deliveries, one planned under epidural analgesia, the second unplanned after a rapid labour. The sixth woman had unstable angina requiring percutaneous coronary intervention in the 28th week of pregnancy and went on to deliver by caesarean section under general anaesthesia. Regional anaesthesia was avoided in this case because of antiplatelet and anticoagulant medication. There is a lack of level-one evidence to direct the management of these women. Clinical decisions were directed by guidelines for the perioperative management of patients with cardiac disease in non-cardiac surgery and the management of all cardiac disease in the obstetric population. A multi-disciplinary approach was taken, with a collaborative plan made for each pregnancy and delivery. A thorough clinical history and examination together with transthoracic echocardiography allows risk stratification of women with coronary heart disease at risk of peripartum cardiac events. Further investigation specific to each woman's management can then be undertaken.

Do resuscitation attempts in children who die, cause injury?

OBJECTIVE

To determine the incidence, type, and pattern of injury related to resuscitation attempts in children who die.

DESIGN

Retrospective review of ambulance, hospital, and necropsy case records.

METHOD

All children who died aged 0-14 years between 1994 and 1996, and underwent a full necropsy at the Victorian Institute of Forensic Medicine (Melbourne, Australia) were identified. Children who were subject to recognised trauma before resuscitation or died because of a congenital abnormality were excluded. The records of all remaining children were reviewed. Children were grouped according to whether resuscitation was attempted or not.

RESULTS

From a total of 346 children who died, 204 (58.6%) were identified as meeting the inclusion criteria. Resuscitation was performed in 153 (75%) children and was started before ambulance arrival in 123 (60.3%) children. Injuries were detected at necropsy in 65 (42.5%) of children who had resuscitation compared with six (11.7%) of children who had no resuscitation (p<0.0001) chi(2) test. All but two of these injuries were of a minor nature consisting principally of bruises or abrasions. Two significant injuries were identified both occurring as a result of readily identifiable resuscitation procedures. The likelihood of injury increased with the length of resuscitation. In children resuscitated for less than 60 minutes the incidence of injury was 27% compared with 62% for children resuscitated for longer ( p<0.0001).

CONCLUSION

This study has shown that cardiopulmonary resuscitation commonly causes minor injuries such as superficial bruises and abrasions and the likelihood of such injury increases with the duration of the cardiopulmonary resuscitation. This information should reassure parents and caregivers that basic life support may be instituted without fear of causing significant injury or adversely affecting outcome in the child with cardiorespiratory arrest. Caution must be exercised when attributing significant injuries to resuscitation attempts and alternative causes must be fully investigated.

The non-specific inhibition of enzymes by environmental pollutants: a study of a model system towards the development of electrochemical biosensor arrays

Previous research has shown that lactate dehydrogenase (LDH) was competitively inhibited by pentachlorophenol (PCP) and a modified assay produced a detection limit of 1 microM (270 microg l(-1)). This work used spectrophotometric rate-determination but in order to move towards biosensor development the selected detection method was electrochemical. The linkage of LDH to lactate oxidase (LOD) provided the electroactive species, hydrogen peroxide. This could be monitored using a screen-printed carbon electrode (SPCE) incorporating the mediator, cobalt phthalocyanine, at a potential of +300 mV (vs. Ag/AgCl). A linked LDH/LOD system was optimised with respect to inhibition by PCP. It was found that the SPCE support material, PVC, acted to reduce inhibition, possibly by combining with PCP. A cellulose acetate membrane removed this effect. Inhibition of the system was greatest at enzyme activities of 5 U ml(-1) LDH and 0.8 U ml(-1) LOD in reactions containing 246 microM pyruvate and 7.5 microM NADPH. PCP detection limits were an EC(10) of 800 nM (213 microg l(-1)) and a minimum inhibition detectable (MID) limit of 650 nM (173 microg l(-1)). The inclusion of a third enzyme, glucose dehydrogenase (GDH), provided cofactor recycling to enable low concentrations of NADPH to be incorporated within the assay. NADPH was reduced from 7.5 to 2 microM. PCP detection limits were obtained for an assay containing 5 U ml(-1) LDH, 0.8 U ml(-1) LOD and 0.1 U ml(-1) GDH with 246 microM pyruvate, 400 mM glucose and 2 microM NADPH. The EC(10) limit was 150 nM (39.9 microg l(-1)) and the MID was 100 nM (26.6 microg l(-1)). The design of the inhibition assays discussed has significance as a model for other enzymes and moves forward the possibility of an electrochemical biosensor array for pollution monitoring.

Striatal cells containing aromatic L-amino acid decarboxylase: an immunohistochemical comparison with other classes of striatal neurons

In a previous study, we described a population of striatal cells in the rat brain containing aromatic L-amino acid decarboxylase, the enzyme involved in the conversion of L-DOPA into dopamine. We have also presented evidence that these cells produce dopamine in the presence of exogenous L-DOPA. In this paper, we further characterize these striatal aromatic L-amino acid decarboxylase-containing cells in order to determine whether they form a subclass of one of the known categories of striatal neurons or if they represent a novel cell type. Using immunohistochemical methods, we compared the morphology and distribution of the aromatic L-amino acid decarboxylase-immunolabeled cells with those of other classes of striatal neurons. Our results show that both the morphology and distribution of aromatic L-amino acid decarboxylase-immunolabeled cells are very distinctive and do not resemble those of cells labeled for other striatal neuronal markers. Double-labeling procedures revealed that aromatic L-amino acid decarboxylase cells do not co-localize somatostatin or parvalbumin, and only a very small percentage of them co-localize calretinin. However, the population of aromatic L-amino acid decarboxylase cells label intensely for GABA.Overall, our results suggest that these aromatic L-amino acid decarboxylase-containing cells represent a class of striatal GABAergic neurons not described previously.

International telemicroscopy with a 3 MV ultrahigh voltage electron microscope

The ability for remote microscope operation via a network connection was added recently to the ultrahigh voltage electron microscope (UHVEM) in Osaka University, and used successfully for the observation of thick biological samples across the Pacific Ocean by researchers at the National Center for Microscopy and Imaging Research (NCMIR) at the University of California San Diego. High-quality images at video rate were transferred by a satellite link and control signals were transmitted by an ISDN connecting the workstations at both sites. Most microscope functions operated from the console of the UHVEM were replicated on the graphical user interface of the remote workstation. By clicking on icons or in boxes in the display window with a mouse, the researcher could operate the UHVEM from the remote-site. The total delay time for sending images and returning control signals was about 0.7 s, which did not interfere significantly with the smooth operation of the instrument. Researchers at the remote site were able to record images on film in the microscope which were later sent to San Diego.

Inhalant abuse and the abuse of other drugs

AIMS

To examine the relationship between inhalant abuse and other substances of abuse.

DESIGN

Survey using a structured interview administered by a single trained interviewer.

SETTING

A juvenile detention facility.

PARTICIPANTS

209 children incarcerated at the facility over a 3-month period.

SELECTION PROCEDURE

Consecutive sample.

INTERVENTIONS

None. MEASUREMENTS/FINDINGS: The structured interview was adapted from the American Drug and Alcohol Survey, which has been extensively used to obtain substance abuse epidemiologic data. We collected information on inhalants, alcohol, marijuana, downers, pep pills, lysergic acid diethylamide (LSD), cocaine, designer drugs, phencyclidine (PCP), Talwin and Ritalin, speed, and narcotics. The chi-square or Fisher exact test were used when appropriate. Mean ages of initial experimentation were as follows: inhalants, 9.7 years; marijuana, 11.9 years; alcohol (inebriated), 12.0 years; cigarettes, 11.2 years; for the remaining substances of abuse, the mean age was 13.2-14.7 years. Thirty subjects had used inhalants. Significant relationships were found between inhalants and cocaine (p = .004), Talwin and Ritalin (p = .001), downers (p = .01), and narcotics (p = .003).

CONCLUSIONS

For children incarcerated in a juvenile detention facility in our community, inhalant abuse is associated with the later use of other substances of abuse. If this finding is replicated in other populations, it underscores the need for effective preventive strategies.

Web-based telemicroscopy

By taking advantage of network-based computing and the recent developments in Web interfaces, centralized research facilities housing specialized and unique imaging instruments along with associated high-performance computing can be made available to researchers for use from their own laboratories. In addition to increasing access and utilization of these facilities, operation over the Internet is expected to enhance research by facilitating collaboration between researchers. We describe the implementation of a platform-independent Web-based system written in Java that supplements automated functions with video-guided interactive, collaborative remote control and data acquisition from an intermediate-high-voltage electron microscope.

Modification of postsynaptic densities after transient cerebral ischemia: a quantitative and three-dimensional ultrastructural study

Abnormal synaptic transmission has been hypothesized to be a cause of neuronal death resulting from transient ischemia, although the mechanisms are not fully understood. Here, we present evidence that synapses are markedly modified in the hippocampus after transient cerebral ischemia. Using both conventional and high-voltage electron microscopy, we performed two- and three-dimensional analyses of synapses selectively stained with ethanolic phosphotungstic acid in the hippocampus of rats subjected to 15 min of ischemia followed by various periods of reperfusion. Postsynaptic densities (PSDs) from both area CA1 and the dentate gyrus were thicker and fluffier in postischemic hippocampus than in controls. Three-dimensional reconstructions of selectively stained PSDs created using electron tomography indicated that postsynaptic densities became more irregular and loosely configured in postischemic brains compared with those in controls. A quantitative study based on thin sections of the time course of PSD modification indicated that the increase in thickness was both greater and more long-lived in area CA1 than in dentate gyrus. Whereas the magnitude of morphological change in dentate gyrus peaked at 4 hr of reperfusion (140% of control values) and declined thereafter, changes in area CA1 persisted and increased at 24 hr of reperfusion (191% of control values). We hypothesize that the degenerative ultrastructural alteration of PSDs may produce a toxic signal such as a greater calcium influx, which is integrated from the thousands of excitatory synapses onto dendrites, and is propagated to the neuronal somata where it causes or contributes to neuronal damage during the postischemic phase.

Altered long-term potentiation in the hippocampus of apolipoprotein E-deficient mice

Recent studies suggest that apolipoprotein E (apoE) plays a neurotrophic role in the central nervous system and that an aberrant function of this molecule might result in neurodegeneration. Supporting this notion, apoE-deficient mice show neurodegenerative and cognitive alterations. To characterize physiological changes associated with synaptic damage and cognitive impairment in apoE-deficient mice, we investigated synaptic plasticity in the hippocampus of urethane anesthetized mice. Electrical stimulation was delivered to the perforant pathway and the resulting evoked field excitatory postsynaptic potential (EPSP) and population spike were recorded in the hilus. Long-term potentiation, as measured in the population spike, was reduced by 50% in apoE-deficient mice when compared to wild-type controls. In contrast, there were no significant differences in the evoked field EPSP between wild-type and apoE-deficient mice following high-frequency stimulation. These results support the notion that cognitive impairment and synaptic loss in the hippocampus of apoE-deficient mice might be associated with impaired long-term potentiation.

Intravenous tenoxicam for analgesia following laparoscopic cholecystectomy

In a double-blind, placebo-controlled clinical trial (power of 80% to detect a 30% reduction in morphine consumption, P < 0.05) we have determined that intraoperative intravenous administration of tenoxicam 40 mg during laparoscopic cholecystectomy, when compared with placebo, was associated with a significant reduction in consumption of morphine at 6 hours and 12 hours (P < 0.05) but not at 24 hours, when assessed by patient-controlled analgesia. Furthermore there was a significantly greater requirement for "rescue" analgesia with intramuscular morphine in the placebo group during the period of the study. There was no difference between the groups in pain scores, either at rest or on movement, nor in the incidence of nausea and vomiting. No patient in either group suffered a respiratory rate less than 8/min or oversedation at any time, and there were no other adverse effects.

Electron tomography of large, multicomponent biological structures

Electron tomography is an extremely useful method for deriving three-dimensional structure from electron microscope images. The application of this technique to the reconstruction of large, complex structures such as mitochondria is described in conjunction with several tools for segmentation, measurement, classification, and visualization. In addition, the use of massively parallel computers to perform the tomographic reconstruction efficiently using R-weighted backprojection or iterative techniques is described.

Fine structure of the murine leptin receptor gene: splice site suppression is required to form two alternatively spliced transcripts

The fine structure of the murine leptin receptor gene (Lepr) is described. Duplicated ligand binding domains (conserved among cytokine receptors) are found in eight exons (coding exons 3 to 6 and 8 to 11). Thus, it is possible that a single leptin receptor molecule could have two functional ligand binding domains. The transmembrane region of Lepr is in coding exon 16 while the juxtamembrane JAK docking site is in coding exon 17. For all membrane-bound forms, the transcript must include 17 invariant exons and 1 alternatively spliced 3' terminal exon. The transcript encoding the soluble receptor (Re) includes 14 coding exons and an alternatively spliced 3' terminal exon. We have identified two splice variants (Rc and Re) for which there are no intervening sequences between the two final exons. This unusual juxtaposition of exons requires that splice donor sites at the 5' end of the respective terminal exons be ignored in the production of these splice variants. We suggest that splice site suppression is responsible for the formation of two of the alternatively spliced forms of the mouse Lepr gene. The juxtaposition of two coding exons separated by a consensus splice donor sequence is the structural substrate for this mode of alternative splicing. We present evidence that the Rc form is expressed in human tissues while the Re form, the soluble receptor, is not expressed.

The health of a group of young Australians in a New South Wales juvenile justice detention centre: a pilot study

OBJECTIVE

To consider the health profile of a sample of young, largely male Australians as assessed on their admission to a New South Wales Juvenile Justice Detention Centre.

METHOD

A retrospective analysis of primary care nurse health records for 100 sequential admissions.

RESULTS

Of the 97 males and three females (mean age = 15.9 years), 30 were Aboriginal and 39 did not live with either parent at the time of admission. Respiratory illness, such as bronchitis and asthma were common. These diagnoses were overshadowed by histories of significant physical injury. The sample was at high risk of sexually transmitted disease. Forty-six per cent had prior contact with a mental health professional, 26% reported they had thought of suicide and 9% reported having attempted suicide. There was a high prevalence of substance abuse.

CONCLUSION

The health of these young Australians is at risk from every perspective. Improving the quality of their health assessments is an important issue for the clinicians who attend them as individuals and for policy makers who aim to reduce the considerable social and economic cost of juvenile crime. The discussion of these results from one centre has revealed opportunities to make such improvements. There is a need for a gathering of expertise to address the issue, preferably on a national basis.

Lesions in the dentate hilum and CA2/CA3 regions of the rat hippocampus produce cognitive deficits that correlate with site-specific glial activation

Thirty male rats pressed a lever three times (FR3) when a stimulus light (sD) was off to obtain sucrose pellets. They were then evenly divided into sham Controls versus groups lesioned bilaterally in the hippocampus by stercotaxic injection of ibotenic acid into the dentate hilum (HIL) or the CA2/CA3 region (CA2/3). On measures of recall of the FR3-sD task taken during the initial 30 min of a postlesion test session, the CA2/3 and especially the HIL groups showed significant (p < .05) impairments relative to the Controls. During an ensuing 30-min period, rats were reshaped to criterion, beginning at FR1, and no appreciable intergroup differences were noted on this schedule or at FR1-sD. At FR2-sD, the HIL but not the CA2/3 group showed some impairment relative to Controls. At FR3-sD, both the CA2/3 and HIL groups had impaired task performance. An immunocytochemical index of glial activation showed higher reactivity in CA2/3 or the dentate hilum among CA2/3 or HIL animals, respectively, that was associated with the degree to which they showed an FR3-sD performance deficit.

Electron tomography of neuronal mitochondria: three-dimensional structure and organization of cristae and membrane contacts

The structure of neuronal mitochondria from chick and rat was examined using electron microscope tomography of chemically fixed tissue embedded in plastic and sliced in approximately 500 nm-thick sections. Three-dimensional reconstructions of representative mitochondria were made from single-axis tilt series acquired with an intermediate voltage electron microscope (400 kV). The tilt increment was either 1 degree or 2 degrees ranging from -60 degrees to +60 degrees. The mitochondrial ultrastructure was similar across species and neuronal regions. The outer and inner membranes were each approximately 7 nm thick. The inner boundary membrane was found to lie close to the outer membrane, with a total thickness across both membranes of approximately 22 nm. We discovered that the inner membrane invaginates to form cristae only through narrow, tubular openings, which we call crista junctions. Sometimes the cristae remain tubular throughout their length, but often multiple tubular cristae merge to form lamellar compartments. Punctate regions, approximately 14 nm in diameter, were observed in which the inner and outer membranes appeared in contact (total thickness of both membranes approximately 14 nm). These contact sites are known to a play a key role in the transport of proteins into the mitochondrion. It has been hypothesized that contact sites may be proximal to crista junctions to facilitate transport of proteins destined for the cristae. However, our statistical analyses indicated that contact sites are randomly located with respect to these junctions. In addition, a close association was observed between endoplasmic reticulum membranes and the outer mitochondrial membrane, consistent with the reported mechanism of transport of certain lipids into the mitochondrion.

Quantitative analysis of periodontal defects in a skull model by subtraction radiography using a digital imaging device

This paper describes a quantitative study of periodontal defects produced in a skull model using subtraction images obtained with a digital imaging device, radiovisiography (RVG). Analysis using radiovisiography was compared to changes in weight and volume determined by physical measurements. Four types of periodontal defects were studied: 2-wall, 3-wall, crater, and furcation. All defects were fabricated on posterior teeth in alveolar bone and done with triplicate samples. Defects were made progressively larger in approximately 1 mm steps allowing examination of defects ranging from 1 mm to 5 mm. Radiographic images before and after each step were obtained with a radiovisiography system and subtracted. Changes in weight and defect volume were also recorded and compared to the results obtained after each step from the digital subtraction. For each defect type, a regression analysis was performed to compare changes in bone mass determined by weight with calculated bone loss determined by subtraction radiography or by volume measurements. When the calculated bone losses were compared to the true bone losses it was evident that the subtraction method frequently, but not always, underestimated the lesion sizes. For all lesions the average underestimation was 22%. The largest underestimation occurred with furcation lesions where the measured bone loss was underestimated on average by 67%. Two-walled lesions were underestimated by 30%, 3-wall lesions by 3%, and crater lesions were overestimated by 10%. Furthermore, the accuracy of each 1 mm step in bone loss varied considerably. At present, the imaging system is not sufficiently accurate to establish absolute determinations of the bone loss, but would be clinically useful in determining relative changes in bone loss or gain after treatment. In addition, caution must be taken in interpreting a given change in calculated bone loss, since considerable variation may result in either underestimation or overestimation of bone loss.

Glutamate-dependent long-term presynaptic changes in corticostriatal excitability

We have previously shown that brief high frequency stimulation of the anteromedial prefrontal cortex induces a long-term decrease in excitability of the glutamatergic corticostriatal terminal field. In contrast, a long-term increase in presynaptic corticostriatal excitability may be induced by presenting two brief cortical tetanizing stimuli separated by 2-3 min such that the second tetanus coincides with a period of increased excitability elicited by the first. In the present study, we examined the glutamate receptor subtypes involved in these long-term changes in presynaptic excitability. A specific glutamate receptor antagonist was infused into the rat striatum 10-25 min prior to either a single or double cortical tetanic stimulation. To eliminate the participation of intrinsic striatal cells, a subset of animals received a striatal kainic acid lesion eight to 20 days before the recording experiment. Antagonists of the N-methyl-D-aspartate and metabotropic glutamate receptor subtypes were effective in blocking the decrease in excitability induced by single cortical tetanic stimulation whereas an antagonist of the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid/kainate receptor did not prevent the induction of a long-term reduction in excitability. In contrast, each of these antagonists prevented the induction of a long-term increase in excitability. These long-term modifications in excitability of the presynaptic glutamate axon terminals appear to be induced by similar mechanisms to those postulated to operate in long-term potentiation and depression. These enduring changes in presynaptic excitability are likely to represent important mechanisms for the selective modification of information processing in the striatum.

Homogeneity of fruits and vegetables comminuted in a vertical cutter mixer

The homogeneity of comminuted composites of 20 lb samples of apples, cabbage, and green beans containing field-incurred residues of p, p'-methoxychlor was studied to determine whether a 5 min comminution in a 40 qt vertical cutter mixer produces a homogeneous composite and whether the size of test portions used accurately represents the composite. Duplicate test portions of 100, 50, 25, 10, 5, and 2 g taken from each of 6 separate sections of the mixer were analyzed by standard pesticide residue methodology for p, p'-methoxychlor. Results of this study confirmed that comminution of fresh produce in a 40 qt vertical cutter mixer, according to instructions described in the U.S. Food and Drug Administration's Pesticide Analytical Manual, Volume I, Section 203B, produces a homogeneous composite. No significant differences were found in the data for the 3 crops taken from the 6 sections of the mixer. Test portion weights of 100, 50, and 25 g produced equivalent results for all 3 crops. Statistically significant differences were observed for cabbage at 2, 5, and 10 g and for green beans at 2 g.

Effects of nicotine on dopaminergic nigrostriatal axons requires stimulation of presynaptic glutamatergic receptors

An electrophysiological method for evaluating changes in axonal excitability was used to examine presynaptic effects of the local striatal administration of nicotine on nigrostriatal dopaminergic terminal axons in the rat. To eliminate postsynaptic interactions, intrinsic striatal neurons were destroyed with a unilateral kainate lesion performed 10 to 15 days before the recording experiments. Excitability was assessed by determining the striatal stimulus current just sufficient to elicit an antidromic response from the striatal terminal field of a dopaminergic nigral neuron on 95% of the stimulus presentations. Local nicotine infusion (1-100 microM/0.3 microliter) produced a dose-dependent increase in excitability. Previous intrastriatal administration of the nicotine receptor antagonists mecamylamine or chlorisondamine blocked the nicotine effect and subsequent administration reversed the nicotine response. Increased dopamine autoreceptor stimulation, presumably resulting from nicotine-induced dopamine release, appeared to oppose the nicotine-induced increase in excitability. Accordingly, in animals in which dopamine synthesis was blocked with alpha-methyl-p-tyrosine (250 mg/kg, 12 and 2 h before recording), the nicotine-induced increase in terminal excitability was larger than in untreated rats. Simultaneous intrastriatal administration of the glutamate receptor antagonists, 6,7-dinitro-quinoxaline-2,3-dione and 2-amino-7-phosphonoheptanoate, prevented the nicotine-induced increase in excitability in animals with or without alpha-methyl-p-tyrosine pretreatment. We conclude that the nicotine-induced increase in nigrostriatal terminal excitability is an indirect effect resulting from a nicotine-evoked increase in glutamate release and a subsequent increase in the stimulation of presynaptic glutamate heteroreceptors on the dopamine-containing terminals.

Amphetamine-induced changes in nigrostriatal terminal excitability are modified following repeated amphetamine pretreatment

To investigate neural mechanisms associated with behavioral sensitization to amphetamine, we studied the effect of an intrastriatal infusion of amphetamine on nigrostriatal axon terminal electrical excitability in rats following withdrawal from repeated systemic treatment. Rats were injected with amphetamine 2.5 mg/kg s.c. or saline daily for 4 days. Either 24 h or 14 days after the last injection, extracellular recordings were obtained from dopaminergic neurons of the substantia nigra, in a blind design in which the experimenter did not know the pretreatment regime. In order to assess the electrical excitability of the nigrostriatal axonal field, neurons were activated antidromically by stimulating their terminal fields in the striatum. As previously reported, striatal infusion of amphetamine (1 microM/0.3 microliter) in control animals resulted in a significant reduction in excitability as indicated by an increase in striatal stimulus current necessary to evoke antidromic activity. In contrast, intrastriatal amphetamine administration to amphetamine-pretreated animals did not decrease excitability. Spontaneous firing rates and patterns of cell discharge did not differ between saline- and amphetamine-treated animals. The chronic amphetamine-induced change in the effect of an acute intrastriatal amphetamine infusion on nigrostriatal terminal excitability may be due to enduring alterations in the amphetamine-induced release of dopamine and other striatal neurotransmitters or to changes in the sensitivity of presynaptic hetero- and/or autoreceptors on the dopaminergic axons.

A flexible environment for the visualization of three-dimensional biological structures

"Ducky" is a flexible and versatile software system for processing, rendering, and animating 3D datasets. The system is based on a powerful run-time interpreted language similar to C. The language includes many built-in functions for animation, rendering, shading, surface definition, and the creation of interactive menu and window-based visualization environments. Both volume and surface rendering methods are provided and may be combined in a single visualization. Ducky can create animations of a sequence of different views of a structure either within a 3D volume or across a series of volumes. Scripts implementing several common visualization tasks are provided. The system is readily extendible. Existing scripts can be modified or new scripts written to create additional interactive environments and processes.

Aromatic L-amino acid decarboxylase immunoreactive cells in the rat striatum: a possible site for the conversion of exogenous L-DOPA to dopamine

The efficacy of L-dihydroxyphenylalanine (L-DOPA) in ameliorating the symptoms of Parkinson's disease (PD) is attributed to its conversion to dopamine (DA) by the enzyme aromatic L-amino-acid decarboxylase (AADC) in the striatum. Although the site of this conversion in the DA-denervated striatum has yet to be identified, it has been proposed that L-DOPA could be converted to DA at non-dopaminergic sites containing AADC. In the present study, we used immunocytochemical techniques to examine the localization of AADC and DA in the striatum of rats with a unilateral 6-hydroxydopamine (6-OHDA) lesion of the nigrostriatal dopaminergic projection. In the DA-denervated striatum, we observed AADC-immunoreactive (-IR) cells with morphological characteristics similar to a class of small aspiny interneuron. Although usually obscured by a dense plexus of AADC-IR fibers, these cells could also occasionally be detected in the intact striatum. Acute administration of L-DOPA to DA-denervated animals elicited contralateral rotational behavior as well as a pronounced c-fos protein immunoreactivity in the striatum ipsilateral to the lesion. Following acute administration of L-DOPA, but not after acute saline, DA-IR cells were detected in the denervated striatum. These DA-IR cells are similar in morphology and were found in the same location as the AADC-IR cells. These results strongly suggest the existence of a class of AADC-containing striatal cells that can form DA from exogenous L-DOPA in the rat. In the DA deafferented striatum, DA produced by these cells from exogenous L-DOPA could be released to exert physiological effects on DA receptive tissue. It is possible that similar cells could contribute to the efficacy of L-DOPA in the treatment of Parkinson's disease.

Conditions for electron tomographic data acquisition

The conventional algorithms employed in electron microscope tomography require that the series of images obtained from different orientations of the specimen each represent a parallel orthographic projection under uniform magnification. Electron microscope optics can produce distortions in images that may affect the accuracy of a tomographic reconstruction. These distortions result in images with differential rotation and magnification of regions of a thick or highly tilted specimen located at different distances with respect to the plane of focus. The distortions increase in magnitude and may significantly affect the accuracy of the tomographic data when images are acquired under current center misalignment or non-eucentric positioning of the specimen. An additional source of error can be introduced if the condenser lenses are adjusted to compensate for the intensity attenuation due to the increased beam path length as the specimen is tilted. The change in beam crossover position due to adjustment of the condensers alters the beam divergence and may introduce systematic changes in magnification over the tilt series. The process of alignment of the tilt series will propagate these errors to more central regions of the image. In most cases, with proper consideration, it is possible to minimize these errors to levels where they will have negligible effects on the resolution of the tomographic reconstruction.

Electron microscopic evidence for neurotoxicity in the basal ganglia

The dopaminergic projection from the substantia nigra to the neostriatum is vulnerable to several neurotoxins including 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), amphetamine, and 5-hydroxydopamine. We have treated rats or mice with these agents and examined various regions of their brains with a combination of Fink-Heimer, immunohistochemical, serial-section electron microscopic, and three-dimensional reconstruction methods. In addition to degenerating or swollen axons, we found darkened glial processes and some damage to postsynaptic cells and dendrites. The particular effects observed critically depend on experimental variables such as dose, time, species and strain and raise questions about the correlation of light and electron microscopic results. These studies provide the basis for a discussion of the advantages and disadvantages of an ultrastructural examination of the effects of neurotoxins.

Cerebellar-responsive neurons in the thalamic ventroanterior-ventrolateral complex of rats: in vivo electrophysiology

In vivo intracellular recordings were obtained from identified thalamocortical neurons in the ventroanterior-ventrolateral complex in urethane-anesthetized rats. This thalamic nucleus has few interneurons. Neurons that responded to cerebellar stimulation were injected intracellularly with horseradish peroxidase or biocytin and examined with light and electron microscopy (see companion paper). Intrinsic membrane properties and voltage-dependent rhythmic activity of cerebellar-responsive ventroanterior-ventrolateral neurons were similar to those described previously for thalamic neurons. Thus, in addition to conventional "fast" Na(+)-dependent spikes, rat ventroanterior-ventrolateral neurons had "slow" Ca(2+)-mediated low-threshold spikes and membrane conductances that supported rhythmic oscillations. Two modes of spontaneous activity were observed: (i) a tonic firing pattern that consisted of irregularly occurring fast spikes that predominated when the membrane potential was more positive than about -60 mV, and (ii) a rhythmic firing pattern, observed when the membrane potential was more negative than about -65 mV, composed of periodic (4-8 Hz) membrane hyperpolarizations and ramp depolarizations that often produced a low-threshold spike and a burst of fast spikes. In some neurons, spontaneous fast prepotentials were also observed, often with a relatively constant rate (up to 70 Hz). Cerebellar stimulation elicited excitatory postsynaptic potentials that in some cases appeared to be all-or-none and were similar in form to fast prepotentials. Stimulation of ipsilateral motor cortex elicited a short-latency antidromic response followed by a monosynaptic excitatory postsynaptic potential, which had a slower rise time than excitatory postsynaptic potentials evoked from cerebellum, suggesting that cortical inputs were electrotonically distal to cerebellar inputs. In the presence of moderate membrane hyperpolarization, the cortically evoked excitatory postsynaptic potential was followed by a long-lasting hyperpolarization (100-400 ms duration), a rebound depolarization and one or two cycles resembling spontaneous rhythmic activity. Membrane conductance was increased during the initial component of the long hyperpolarization, much of which was probably due to an inhibitory postsynaptic potential. In contrast, membrane conductance was unchanged or slightly decreased during the latter three-quarters of the long hyperpolarization. The amplitude of this component of the long hyperpolarization usually decreased when the membrane was hyperpolarized with intracellular current injection. Thus, both disfacilitation and an inhibitory postsynaptic potential may have contributed to the latter portion of the cortically-evoked long hyperpolarization. The cortically-evoked inhibitory postsynaptic potentials likely originated predominantly from feedforward activation of GABAergic neurons in the thalamic reticular nuclei.(ABSTRACT TRUNCATED AT 400 WORDS)

The distribution of cholinergic perikarya with respect to enkephalin-rich patches in the caudate nucleus of the adult cat

The distribution of cholinergic interneurons with respect to enkephalin-rich patches in the caudate nucleus of the cat was examined using both computer-assisted 3-D reconstruction and immunocytochemical techniques. Examination of the 3-D distribution of perikarya staining for choline acetyltransferase (ChAT) revealed that these cells were not evenly distributed within the caudate nucleus but exhibited areas of increased and decreased density. Comparison of the 3-D distribution of cholinergic perikarya to that of the enkephalin-rich patches indicated that areas of increased ChAT+ cell density often corresponded to the positions of enkephalin-rich patches within the dorsal-lateral caudate nucleus. At more ventral regions, there was no clear correspondence between areas of increased ChAT+ cell density and enkephalin-rich patches. In agreement with these observations, a quantitative analysis of sections double-labeled for ChAT and enkephalin revealed that the density of cholinergic neurons within enkephalin-rich patches was twice that in the surrounding tissue in the dorsal region of the caudate nucleus. In contrast at more ventral levels, the difference in the density of ChAT+ cells in enkephalin-rich patches did not significantly differ from that in the surrounding striatal tissue. Both the results of the 3-D and the double-labeling analysis suggest that cholinergic neurons are not evenly distributed within the caudate nucleus of the cat but form loose clusters which are associated dorsally with the enkephalin-rich patches. These results also provide further evidence of heterogeneity within the striosomal compartment in the cat.

Compartmental organization of the peptide network in the human caudate nucleus

The mammalian striatum may be divided into a striosomal compartment and a surrounding matrix region. We have examined the distribution of leucine enkephalin (LENK) and substance P (SP) immunoreactivity in relation to striosomes defined by calbindin-D (CABD) staining in alternate 70 microns serial sections from the human caudate nucleus. The distribution of LENK immunoreactivity showed a transition from dorsal to ventral striatum: dorsally, LENK-rich patches were present in a lightly stained matrix; mid-ventrally, annular patches of LENK staining with a lighter core were seen. These patches corresponded to striosomal regions defined by CABD-poor zones. In contrast, in the ventral caudate and nucleus accumbens, LENK-poor zones matched CABD-defined striosomes. CABD staining in the matrix was intense in the dorsal caudate, diminishing ventrally. SP-rich zones in dorsal caudate and SP-poor areas in the mid-ventral region overlapped striosomes. In the ventromedial sector, the SP staining pattern was complex and did not consistently correlate with striosomes. Computer-assisted three-dimensional reconstruction of the striosomal system in the human, based on regions of either high LENK or low CABD immunoreactivity, revealed the existence of considerable long-range order. Patches appeared aligned over several millimeters to form long, horizontal structures in the caudate nucleus, with occasional orthogonal interconnecting crossbridges. Our results are in accord with previous work in the human and in other species. These three-dimensional networks are strikingly similar across individuals and may relate to the segregation of and interactions between striatal circuits.

Serial section electron tomography: a method for three-dimensional reconstruction of large structures

We present a method for combining single axis tomography and serial sectioning techniques to derive a three-dimensional reconstruction of large structures at electron microscopic resolution. This serial-tomography method allows the use of sufficiently thin sections to achieve adequate resolution with electron tomography, yet enables the generation of large reconstructions with considerably fewer sections than would be required using a serial thin section reconstruction technique. Serial thick sections (1-2 microns) are cut through the structure of interest, tomographic volume reconstructions are obtained for each section from a single axis tilt series, and the resulting series of volumes are then aligned and combined to form a single large volume. The serial-tomography method is illustrated with several samples, including red blood cells, the Golgi apparatus, and a spiny dendrite of a cortical pyramidal neuron. In some of these samples, the reconstruction is compared to correlated light microscopic views. The resulting large volume reconstructions appear to represent accurately the size and shape of objects such as red blood cells and spiny dendrites. The continuity of complex, tortuous structures such as the Golgi apparatus is also maintained across serial volumes. These examples demonstrate that it is possible to align and link a series of tomographic volumes accurately and that serial-tomography is a useful method for reconstructing relatively large structures without resorting to large numbers of serial thin sections.

5-hydroxydopamine-labeled dopaminergic axons: three-dimensional reconstructions of axons, synapses and postsynaptic targets in rat neostriatum

Previous studies employing 5-hydroxydopamine to identify nigrostriatal dopaminergic axons and their synapses found that labeled axons made few synapses or that asymmetric contacts predominated. In contrast, recent studies using tyrosine hydroxylase or dopamine antibody techniques indicate that presumed dopaminergic axons form small symmetric contacts. We re-examined 5-hydroxydopamine-labeled material from the rat neostriatum using serial three-dimensional reconstruction techniques to characterize the morphology of labeled axons, synapses and postsynaptic targets. This ultrastructural analysis revealed a class of heavily labeled axons that are small (0.06-1.5 microns in diameter) and lack large varicosities. These axons form small (0.011-0.09 microns 2), en passant, symmetric synapses, mainly onto dendritic spines and spiny dendritic shafts and, in some cases, onto aspiny dendritic segments near branch points. The sites of these synapses along the axon appeared unrelated to the locations of axonal enlargements, suggesting that counting varicosities may not be an accurate indication of the extent of dopaminergic innervation in the neostriatum. The characteristics of these 5-hydroxydopamine-labeled elements correspond in all respects to axons and synapses identified as dopaminergic by immunohistochemistry in previous studies. In tissue in which all labeled and unlabeled synapses were classified, approximately 9% of all synapses were identified as dopaminergic by this type of label. Three-dimensional reconstructions provided additional insight concerning the interaction of dopaminergic afferents with postsynaptic striatal targets and their relation to other afferents to these neurons. They reveal that a short, unbranched dopaminergic axonal segment can make multiple synapses onto dendritic spines, shafts and branch points of one or more dendrites. In addition, one dendrite can receive contacts from several labeled axons. Dopamine synapses onto spines are always associated with unlabeled, asymmetric synapses onto the same spine. Synapses of various morphologies with a distinctly different, lighter form of labeling were much rarer, and may represent other aminergic afferents to the neostriatum. The presence of this second form of label in earlier 5-hydroxydopamine studies may have contributed to the long-standing controversy over the appearance of dopaminergic synapses examined by different techniques. Our results help to resolve this controversy and confirm that the nigrostriatal projection makes small symmetric synapses with a variety of striatal targets.

Telemicroscopy

The feasibility of operating an electron microscope from a remote location using a high-speed computer network has been investigated. A 400 kV electron microscope was modified so that most microscope parameters and stage movement (x, y, z and tilt), can be controlled by a local host computer. The host computer also controls acquisition of digital images from the microscope from either a TV or a slow-scan CCD camera. A computer located at a remote site may send commands to the host computer via a fiber optic network to receive digital images and information concerning the status of microscope. Such a system has been demonstrated at the SIGGRAPH 1992 conference in Chicago and the Supercomputing 92 conference in Minneapolis, where we remotely collected three-dimensional image data sets using the electron microscope in San Diego. This approach, referred to as "telemicroscopy", promises to make possible live microscopy teleconferencing and thereby increase the accessibility and effective usage of the limited number of specialized microscopy resources.

Cholinergic neurons are distributed preferentially in areas rich in substance P-like immunoreactivity in the caudate nucleus of the adult cat

The distribution of cells stained immunocytochemically for the cholinergic marker choline acetyltransferase was compared to the pattern of substance P immunoreactivity in the caudate nucleus of adult cats using a double-label immunocytochemical protocol and three-dimensional reconstructions of adjacent sections single-labeled for either substance P or choline acetyltransferase. Substance P immunoreactivity was distributed in a highly complex mosaic within the caudate nucleus of the cat. In the dorsal caudate nucleus, substance P-rich zones consisting of either clusters of substance P-positive cell bodies or fibers were seen against a lighter staining background. The density of cholinergic neurons was found to be significantly greater within these substance P-rich patches in comparison to surrounding regions. The pattern of substance P immunoreactivity within the ventral caudate nucleus differed from that in more dorsal regions. Clear substance P-rich patches were not seen in this region, but a large substance P-rich area consisting of a dense plexus of substance P-containing fibers was visible. Embedded within this substance P-rich area were fairly discrete patches of light substance P staining. As in the dorsal caudate nucleus, increased numbers of cholinergic neurons and processes were associated with substance P-rich regions in the ventral caudate nucleus. Choline acetyltransferase-positive perikarya also appeared to be concentrated in substance P-rich areas in the nucleus accumbens and olfactory tubercle. The results of this study suggest that a close relationship exists between the distribution of substance P fibers and cholinergic perikarya in the striatum of the cat.

Lichen sclerosus, genital trauma and child sexual abuse

OBJECTIVE

To describe the clinical features of lichen sclerosus affecting the genitalia of three unrelated prepubertal girls in whom concerns of sexual abuse had been raised.

CLINICAL FEATURES

three girls ranging from 4 to 9 years of age presented with similar genital and anal findings. Their labial skin was atrophic with pale opalescent patches and a variable amount of labial bruising, haemorrhagic blistering and bleeding. In two, the perianal skin was involved in a similar fashion. In each case the hymen was normal with no sign of acute or chronic trauma.

CONCLUSIONS

Lichen sclerosus affecting the genitalia of prepubertal females is an uncommon condition that may be mistaken for trauma associated with sexual abuse. An awareness of its clinical features is essential not only for those doctors who examine children for physical signs of sexual abuse but also for primary care doctors who may be confronted with an apparently abused child. Early recognition of this disease should, in the absence of other concerns, prevent unnecessary intervention by police and child protection workers.

Ultrastructural examination of enkephalin and substance P input to cholinergic neurons within the rat neostriatum

Enkephalin and substance P-containing inputs to cholinergic perikarya were examined in the rat neostriatum using an ultrastructural immunocytochemical double-labeling protocol. Sections of rat neostriatum were double-labeled for either choline acetyltransferase (ChAT) and substance P or ChAT and enkephalin using silver intensified colloidal gold and peroxidase as labels. Regions containing both ChAT-positive neurons and peroxidase reaction product were identified in the light microscope prior to sectioning for electron microscopy. Substance P-containing terminals which contained round synaptic vesicles and made symmetrical synaptic contacts were commonly observed in the neostriatum. Substance P synapses onto ChAT-positive perikarya and dendrites were frequently observed: up to 5 synaptic contacts were observed onto a ChAT-positive dendrite. Enkephalin labeling was also seen in a population of axon terminals containing round synaptic vesicles and exhibiting symmetrical synaptic specializations. In contrast to substance P-containing terminals, relatively few synaptic contacts were observed onto ChAT-positive labeled perikarya and dendrites although enkephalin-labeled terminals were seen in frequent contact with perikarya and dendrites of unlabeled spiny neurons. Since enkephalin and substance P are contained within different populations of striatal spiny neurons, the results of the present study suggest that these two types of neurons differ in their intrinsic striatal connections.

Programs for visualization in three-dimensional microscopy

Three-dimensional data representing biological structures can be derived using several methods, including serial section reconstruction, optical sectioning, and tomography. The investigation, comprehension, and communication of structural relationships to others is greatly facilitated by computer-based visualization procedures. We describe SYNU, a suite of programs developed for interactive investigation of three-dimensional structure and for the production of high-quality three-dimensional images and animations. We illustrate the capabilities of SYNU in applications to biological data obtained by confocal light microscopy, serial section, and high-resolution electron microscopy from investigations at the cellular, subcellular, and molecular levels.