Search

The afferents to the periaqueductal gray in the rabbit have been described following hydraulic pressure injection of horseradish peroxidase at various sites throughout this structure. Every third section was reacted with tetramethylbenzidine, for the localization of afferent neurons. At the site of the deposit alternate sections were reacted with tetramethylbenzidine, Hanker-Yates reagent, or diaminobenzidine, for comparative assessment of the injection site. A large number of retrogradely labelled cells, assessed by bright- and dark-field microscopy, were observed in a wide range of areas throughout the brain. Major labelled areas within the telencephalon were cortical areas 5, 20, 21, 32 and 40. Within the diencephalon, the hypothalamus contained quantitatively by far the largest number of labelled cells. Of these nuclei, the dorsal pre-mammillary nucleus contained the largest number of labelled cells. Considerable labelling was also found within medial and lateral preoptic nuclei, anterior hypothalamic area, and ventromedial hypothalamic nucleus. Another diencephalic region containing a significant number of retrogradely labelled neurons was the zona incerta. At midbrain, pontine and medullary levels, additional labelled regions were: the substantia nigra, cuneiform nucleus, parabigeminal nucleus, raphe magnus, and reticular areas. Heavy labelling was seen within the periaqueductal gray itself, rostral and caudal to deposits placed within each subdivision. In addition, a large number of other areas labelled throughout the brain (Tables 2A-D). Not only were some differences noted in the pattern of labelled cells with deposits placed rostrally or caudally within periaqueductal gray, but certain topographical differences with respect to the degree of labelling within nuclei were also seen with injection sites ventral, lateral or dorsal to the aqueduct. In addition, a further difference was noted, in that over one third of the areas labelled with deposits in just one or other of the "divisions" within periaqueductal gray. The results therefore suggest that the periaqueductal gray might be divisible to some extent on the basis of connectivity with intrinsic subdivisions of the complex. It is hoped that, with time, it might prove possible to resolve any such differential input in functional terms. The wide variety of afferent input to the periaqueductal gray, and its strategic location, would seem to place it in a unique position for integrating and modifying a diversity of motor, autonomic, hormonal, sensory and limbic influences.(ABSTRACT TRUNCATED AT 400 WORDS)

Forty five children presenting with a first proven urinary tract infection under the age of 5 years were studied by sequential 99mTc dimercaptosuccinic acid (DMSA) scans. Forty nine kidneys in 40 children had definite defects at presentation, and 39 (80%) of these defects were still present when the DMSA scan was repeated. Changes in the appearance of defects were independent of the presence or degree of reflux at presentation and of symptomatic recurrence of infection, though the combination of new infection and grade 3 reflux (reflux reaching the renal calices with distension) was associated with deterioration. No kidney with a relative DMSA uptake of less than 35% showed any improvement in its cortical defects. Only two kidneys that were initially without defects, in a single patient who had bilateral grade 3 reflux and breakthrough infections, developed defects on subsequent scans. The outcome after urinary tract infection is dependent on the effect of the first infection on the kidney. Occasionally children with grade 3 reflux develop damage during subsequent infections. More widespread use of DMSA scans should improve our understanding of the factors that determine the development of renal damage.

Tc-HIDA is a promising new agent for imaging the biliary system. In this study radiochromatography on paper or Sephadex G25 gel has been used to measure the proportions of TcHIDA, 'hydrolysed Tc' and pertechnetate in solutions from a commercial kit (CIS TCK 15) and in body fluids from patients and rats receiving this radiopharmaceutical. The tissue distribution in male and female rats has shown the radiopharmaceutical to be rapidly removed from the blood by the liver and then excreted via the intestines. There appears to be a sex difference in the uptake in the kidneys and in the urinary excretion in both rats and patients.

Gall-bladder sensitivity to cholecystokinin (CCK) was determined by dynamic cholescintigraphy in 18 patients with radiolucent gall stones and 18 matched controls during an infusion of CCK in which the rate of infusion was increased. In 10 of the matched pairs the patient was more sensitive than the control, in one the control was more sensitive, and in seven no difference was detected (p = 0.012). It is concluded that patients with cholesterol gall stones have increased gall-bladder sensitivity to CCK, and that this may be important in the pathogenesis of this disease.

A total of 115 children under 5 years who presented with a first symptomatic urinary tract infection and who had a 99mTc dimercaptosuccinic acid (DMSA) scan were studied to assess its value and compare the findings with those of other imaging techniques. Renal cortical defects were detected in 65 kidneys by DMSA scan, intravenous urogram, and ultrasound scan combined; 62 (95%) being seen on DMSA scan. The finding of reflux on micturating cystourethrography showed a highly significant correlation with renal defects seen on DMSA scanning, a less close but still significant correlation with abnormalities on intravenous urography, but none with ultrasound scan findings. The sensitivity of the DMSA scan in screening for all grades of reflux is estimated as 0.66, which is higher than that previously reported for the intravenous urogram or ultrasound scan. DMSA scans were less likely to miss grade 3 reflux than the other two methods. DMSA scans are more useful than other upper renal tract imaging techniques in detecting renal defects. Consideration should be given to their use as a first investigation in place of routine intravenous urograms. Ultrasound scans alone will overlook potentially serious urinary tract abnormalities.

Ultrasound findings of 39 spleens and 68 livers in which histology was obtained at laparotomy or autopsy within a month of the examination and four livers in which abnormalities were found clinically by other methods during long-term follow-up were reviewed to evaluate the various sonographic appearances and the accuracy in detecting involvement of the spleen and liver. Only one out of 17 positive spleens had definite ultrasonic focal lesions. Not only small splenic Hodgkin's foci but also larger ones were overlooked. Of 10 positive livers, six showed diffuse inhomogeneity throughout the liver, two showed multiple, well-defined, echo-poor lesions but two showed no significant ultrasonic abnormality even in retrospect. No correlation was found between the type of Hodgkin's disease and the ultrasonic appearance of involved livers. Ultrasonic examination, however, could differentiate other liver abnormalities, such as fatty changes, a cyst and a thrombosed haemangioma from infiltration of Hodgkin's disease. In one case, splenic lesions became echogenic following-chemotherapy.

During screening of 16,800 primary schoolgirls, aged 4-12 years, in Cardiff and Oxford, significant bacteriuria was found in 294 (1-7%). Intravenous urography and micturating cystography were performed in 246 of these girls. The urinary tract was abnormal in 47%. Pyelonephritis with or without vesicoureteric reflux was present in 26% and reflux without renal abnormality in a further 16%. The prevalence of pyelonephritis and reflux was independent of age. With few exeptions kidneys without pyelonephritic scars appeared to be normal in size, even when ureteric reflux was present.

Six children with neuroblastoma and one with ganglioneuroma received [125I] metaiodobenzylguanidine (MIBG) before major surgery. Uptake of [125I]MIBG in the excised tissues was measured by scintillation counting, and the material was submitted for histopathology. The ranges of uptake of [125I]MIBG, expressed as percent of the injected dose per gram of tissue, were as follows: for neuroblastoma 0.0013-0.071, for ganglioneuroma 0.0017-0.0028, and for non-neoplastic control tissues 0.0002-0.011. The quantitative uptake of [125I]MIBG by neuroblastoma varied between different patients and between different parts of individual tumors. The more undifferentiated tumors took up more [125I]MIBG and may be more likely to respond to targeted radiotherapy with MIBG.

Standard dynamic renography procedures are used to produce time-activity curves for defined regions of interest around the kidneys. Further analysis of the acquired data using Fitted Retention and Excretion Equations (FREE) to determine single kidney glomerular filtration rate (GFR) and kidney transit time is performed at the Royal Marsden Hospital, Sutton. The disadvantage of these methods is that the renal function is assessed for the whole kidney and not on a regional basis. The aim of this study was to use parametric imaging to extend the standard analysis so that the parenchyma could be identified and analysed separately from the collecting system. The parenchyma pixel time-activity curves have shorter time-to-peak (TTP) values than the collecting system. TTP parametric images were used to set limits on the TTP values and thus define the parenchyma pixels. The time-activity curves from the parenchyma were further analysed using FREE to produce parametric images of both GFR and effective blood volume. Finally, the original dynamic data were re-analysed so that time-activity and FREE curves were generated for the parenchyma alone. A study of 15 patients (30 kidneys) showed that the extended analysis indicated parenchymal isotope clearance. By comparing the time-activity and FREE curves of the whole kidney with those from the parenchyma alone, a more useful analysis of parenchymal function was obtained. This proved to be particularly useful for patients with pelvi-ureteric junction (PUJ) obstruction.

The hundred and fifty-seven ultrasonographic examinations were carried out in 200 patients with testicular tumour. In 16 cases (8.0%) liver metastases were demonstrated. There were three main patterns: well- or ill-defined echopoor lesions, well-defined echogenic lesions, and "target" lesions. Echopoor liver lesions were found in metastatic seminoma, whilst metastatic teratoma may give any of these three patterns. The value of ultrasound for evaluating the therapeutic response of hepatic metastases from testicular tumour is discussed.