The natural progression of autonomic neuropathy and autonomic function tests in a cohort of people with IDDM.

OBJECTIVE: To test the natural progression of symptoms of autonomic neuropathy (AN) and function tests in subjects with IDDM. RESEARCH DESIGN AND METHODS: Seventy-six subjects with IDDM of < 10 years duration had cardiovascular autonomic reflex tests and were evaluated for signs and symptoms of AN. RESULTS: Fifty-seven subjects (66%) were available for restudy 9 years later (15 had died, 4 could not be located). Of the symptoms of AN, only gastroparesis increased in prevalence (P < 0.01). Of the five cardiovascular AN measures, only the R-R response to the Valsalva maneuver deteriorated (F[1,44] = 10.61, P < 0.01). CONCLUSIONS: The progression of AN in IDDM is monitored best longitudinally by the Valsalva maneuver because of the small variance ratio in repeated measures. Prevalence rates can be monitored by expiration-to-inspiration R-R or Valsalva ratios. Most clinical signs and symptoms of AN do not progress, underscoring the need for objective and quantitative autonomic function tests to identify people at risk for premature death.

Biodistribution of 131I-radiolabelled plasma low density lipoprotein in hyperlipidaemic vervet monkeys.

Low density lipoprotein (LDL) labelled with 131I has been administered to 6 Vervets 2 of which were high responders to an atherogenic Western diet in terms of plasma cholesterol, 2 were low responders and 2 were fed a high carbohydrate control diet. The ratio of hepatic to cardiac activity was recorded for up to 10 days after administration of the labelled LDL. Liver activity had a longer biological half life in the high-responders and this can be interpreted in terms of a variation of hepatic metabolism of LDL, with direct relevance to the human situation.

Quantitative analysis of left-ventricular function using gated single photon emission tomography.

We describe a quantitative method that measures segmental motion of the left ventricle, using tomographic slices obtained by gated single photon emission tomography (GSPECT). These slices contain the major axis of the left ventricle and are presumed to show wall motion directed towards a center of contraction. Values of parameters describing segmental wall motion in GSPECT were obtained from 61 patients, who received a left cardiac catheterization 1 hr later. These values were compared with results of similar calculations applied to data from contrast ventriculography. We conclude that GSPECT allows a detailed and quantitative, noninvasive study of wall motion of all left ventricular segments, with high inter- and intraobserver reproducibility.

Effect of captopril on changes in rats' hearts induced by long-term irradiation.

The aim of this study was to test the efficacy of captopril, an angiotensin-converting enzyme inhibitor and a known suppressor of fibrosis, in preventing late radiation-induced cardiac pathology. Myocardial functional, histochemical and ultrastructural-morphometric studies were done on perfused hearts of rats isolated 3 and 6 months after 60Co gamma irradiation with 20 Gy and age-matched controls. At each time the animals were divided into the following groups: nonirradiated controls; irradiated once with 20 Gy; irradiated as above and given daily doses of captopril; daily doses of captopril without irradiation. The results showed that captopril, while ameliorating the decrease in the indices of capillary function, increase in mast cells, fibrosis, number of atrial granules, and changes in nerve terminals, failed to prevent the progressive functional deterioration of the hearts after irradiation. These findings suggest that an intramyofiber derangement may be involved in the long-term myocardial complications of irradiation.

Lateral neck imaging for spatial localization of parathyroid tissue.

Two patients with an ectopic parathyroid adenoma are described. In both cases the lesions were clearly demonstrated in an anterior view on T1-201/Tc-99m scintigraphy, but were not identified during the first surgical exploration. Failure to identify the ectopic adenoma at surgery in the second patient led to oblique and lateral views being obtained. These views permitted correct depth localization. We, therefore, believe that lateral and oblique views can be of assistance in improving preoperative localization of an ectopic parathyroid adenoma.

Determining locations of intracerebral lesions for proton radiotherapy.

Using an external view of the head, the ability to direct a proton radiotherapy beam at an intracerebral lesion is described, using a biostereometric (BSM) technique. The positions of markers, recognizable on computed tomography (CT) or magnetic resonance (MR) images, at known locations on the skin of a patient's head are related to the site of the lesion seen on the images. The markers' positions are determined by a BSM device, incorporating six video cameras coupled to a computer. A transformation from a coordinate system, defined by the CT or MR images, to another coordinate system, that of the BSM device, allows the proton beam to be directed towards the lesion. Markers used in this work were solid steel spheres for CT and plastic spheres containing oil for MR images.

Scintigraphic evaluation of esophageal transit and gastric emptying in familial dysautonomia.

Gastroesophageal dysfunction is a major cause of morbidity and mortality in patients with familial dysautonomia (FD). Most studies evaluating esophageal and gastric function in FD patients are either insensitive or invasive. Thus we have used a "milk" scan to quantitate abnormalities in esophageal transit and gastric emptying, while searching for gastroesophageal reflux and aspiration in these patients. The quantitative scintigraphic evaluation was performed in 35 patients with FD, 10 of whom were studied after fundoplication, pyloroplasty and gastrostomy. A prolonged esophageal transit time, ranging from 8 s to more than 60 s duration, was demonstrated in 11 patients. Gastroesophageal reflux was detected in 26 patients. In 16 patients delayed gastric emptying ranging from 63-94% was detected at 30 min, and in 13 patients delayed emptying ranging from 37-86% was observed at 120 min. Pulmonary aspiration was detected in 8 non-operated patients, four of whom had abnormal gastric emptying. The scintigraphic analysis of both esophageal transit and gastric emptying in familial dysautonomia is presented, and its role in evaluation and management of these patients discussed.

Analysis of motion of the head.

This study was undertaken to determine the geometric form of the surface on which a fixed point on the head moves as a result of neck motion. Motion of a retroreflective marker on the glabella of six normal subjects was stereoscopically recorded by two video cameras, during a variety of neck motions, performed on command. Near real-time computer analysis in three dimensions of the video images showed the marker moved on a surface that very closely approximated an elliptical paraboloid (with tendency to a hemisphere), after extraneous shoulder motion had been eliminated. Parameters defining the elliptical paraboloids were obtained. Using a reflex microscope, the shape of the articular facets on skull base and superior facets of C1 and C2 of 6 normal subjects were examined. The shapes of all these facets were calculated and also found to be elliptical paraboloids.

Cranio-facial trauma and cerebral SPECT studies using N-isopropyl-iodo-amphetamine (123I).

Cerebral SPECT studies with N-isopropyl-iodo-amphetamine (123I) (IMP) were performed in patients who had suffered cranio-facial trauma, with and without loss of consciousness (LOC). The results were compared with computed tomography (CT). Nine out of ten of those with LOC had normal CT scans and evident photopaenia in IMP studies. It is clear that IMP SPECT scans complement CT in the investigation of patients who have suffered cranio-facial trauma.

Clinical evaluation of the bone marrow imaging agent 99Tcm-phytate in the detection of bone metastases.

The aims of this study were to assess whether 99Tcm-phytate can detect metastatic skeletal lesions, and to compare it with 99Tcm-methylene diphosphonate (99Tcm-MDP) and 99Tcm-labelled human serum albumin nanocolloids (99Tcm-NC). Twenty-four patients with multiple bony metastases, investigated by 99Tcm-MDP whole-body scintigraphy, underwent 99Tcm-phytate bone marrow imaging. A separate bone marrow scintigram with 99Tcm-NC was performed in 20 of the patients. All of the metastatic lesions detected on the 99Tcm-phytate scintigrams exhibited photon-abundant foci only. Most of the 99Tcm-phytate scintigrams detected fewer metastatic lesions than the corresponding bone scintigrams. Visual comparison of the 99Tcm-NC images showed that 13 of 20 99Tcm-NC images were superior to the 99Tcm-phytate images in the detection of metastatic involvement of the skeleton. Thus 99Tcm-phytate should not be used as a bone marrow imaging agent for the detection of skeletal metastases.

Theoretical and experimental considerations linking an environmental stress to expression of endogenous retroviruses in a mammalian tumour.

CBA mice, containing the transplantable CaNT adenocarcinoma were exposed to magnetic fields of 0.5T. Doubling times of the tumours were found to increase significantly from 71 to 123 hours. Electron microscopy of these tumours revealed that the numbers of intracisternal A-type viral-like particles increased from a total of 127 in control mice (counted in 97 fields from 4 different tumours), to 459 in mice exposed to magnetic fields (counted in 95 fields from 5 different tumours). Similarly, intra-cytoplasmic A-type particle numbers increased from 98 to 184. In contrast the number of budding and extracellular C-type virus particles did not differ significantly in mice exposed to the magnetic field. To our knowledge this is the first report linking an environmental stress (magnetic field) to the visible expression of endogenous retro-viral-like type-A particles. We therefore propose the hypothesis that environmental stress may be relevant to the expression of endogenous retroviruses in mammalian cells. Such a mechanism could be relevant in the mechanisms of carcinogenesis and in the rapid evolution of species.

Novel proprioceptive action in stepping down.

A hypothesis is offered which extends the concept of proprioception to use information necessarily obtained during the first part of a complex motion (stepping down) to facilitate the second part. It is suggested that, when the leading foot of a normal person stepping down arrives at its destination, relevant proprioceptive information is used by the following foot in its descent, to render its movement more efficient. Analogy to another effort-minimizing proprioceptive mechanism and a possible mechanical manifestation of the hypothesis are given.

Transit through the distal quarter of the oesophagus in young children.

The transit time of 800 individual boluses through the distal quarter of the oesophagus was measured in 33 scintigraphic oesophageal studies which had been selected as typifying normal swallows in children. The results show that, in children, transit time through the distal quarter including the lower oesophageal sphincter is normally less than 2 seconds and that transit tends to be slower during the first 4 seconds after onset of swallowing.

The "Fisherman's Waders" sign in a bone scan of inferior vena cava thrombosis associated with nephrotic syndrome.

This paper presents a 61-year-old male patient with nephrotic syndrome, hypercoagulability and IVC thrombosis. Increased soft tissue uptake below the level of the mid chest was seen in his bone scan. The term "Fisherman's Waders" sign is suggested for this finding, whose recognition may permit the identification of inferior vena cava obstruction in bone scans. The existence of a cavo-portal shunt was also confirmed by dynamic scintigraphy.

Contribution of calcium and other dietary components to global variations in bone mineral density in young adults.

A research project on comparative international studies of osteoporosis using isotope techniques was organized by the International Atomic Energy Agency (IAEA) with the participation of 12 countries (Brazil, Canada, Chile, China, Croatia, Hungary, Philippines, Russia, Singapore, South Africa, Turkey, and the United Kingdom). Participating centers in 11 countries (all but the UK) made measurements and collected data on men and women aged 15 to 49 years. In addition to studies of bone mineral density (BMD) at the femoral neck and lumbar spine using DEXA, anthropometric, lifestyle, and nutritional data were also collected. The results of the nutritional studies are reviewed in this paper. Overall, about 8% of the observed variability in spine BMD could be attributed to nutritional factors in men and women; in men, no such relationship could be determined. No single nutritional component (not even calcium) stood out as being of particular importance across all participating centers.

Biliary atresia and neonatal hepatobiliary scintigraphy.

Hepatobiliary scintigraphy using Tc-99m diethyl IDA was performed on 14 jaundiced neonates. It aided greatly the differential diagnosis between neonatal hepatitis and biliary atresia. Limitations in the interpretation of the results are described, as neonatal hepatitis may be accompanied by biliary excretion ranging from zero to normal. Also both biliary atresia (intra- and extrahepatic) and neonatal hepatitis may show no biliary excretion within 24 hours.

Pediatric esophageal scintigraphy. Results of 200 studies.

Esophageal transit of a small volume of watery liquid has been observed scintigraphically in 200 studies performed on patients aged between 6 days and 16 years. Qualitative information concerning esophageal morphology and function in the various phases of deglutition, and scintigraphic features of achalasia, stenosis, and other pathologies are described. Measured esophageal transit time and its normal variation, its relevance to the diagnosis of esophagitis, and the monitoring of treatment are discussed. This technique observing distinct deglutitions has proven a useful diagnostic tool. Its advantages and limitations are discussed in comparison with other methods.

Radionuclide angiocardiography in the diagnosis of congenitally corrected transposition of the great arteries.

Congenitally corrected transposition of the great arteries (CTGA) may constitute a pitfall for interpretation of radionuclide angiocardiography, since the two anatomic discordances cancel each other from a physiologic point of view. However, the unusual shape of the ventricles (due to ventricular discordance) and the relative position of the great arteries (due to transposition) can allow a clear scintigraphic diagnosis, especially for CTGA with mild or absent associated congenital anomalies. Five cases are described. Gated cardiac blood pool imaging is particularly helpful since it permits multiple views, allowing a more detailed study of the scintigraphic signs.

Telemedicine in South Africa: success or failure?

A national telemedicine system for South Africa was planned in 1998. In the first phase, starting in 1999, 28 pilot sites were established in six provinces. The initial applications were teleradiology, tele-ultrasound for antenatal services, telepathology and tele-ophthalmology. Telemedicine equipment was connected by ISDN at 256 kbit/s. From January to September 2000, 2663 radiographic studies were performed at the three Northwest Province teleradiology transmission sites, of which 264 studies (10%) were selected for specialist radiologist reporting by teleradiology. From June to August 2000, nine antenatal care tele-ultrasound consultations were performed in the Northern Cape Province and four transfers were avoided through the use of telemedicine. One area of concern is the relatively low usage of the telemedicine system, which raises questions about its cost-effectiveness. The experience of telemedicine in South Africa confirmed, as others have found, that common problems relate to the technical and organizational challenges of introducing telemedicine.