Molecular genetic diagnosis of the familial myxoma syndrome (Carney complex)

We describe an individual in whom molecular genetic testing provided a diagnosis of the Carney complex, an autosomal dominant syndrome comprising cutaneous and cardiac myxomas, spotty pigmentation of the skin, and endocrinopathy. Recently, we localized the Carney complex disease gene to chromosome region 17q2. Our patient was a member of a family segregating the Carney complex, but was not, himself, initially thought to be affected. Haplotype analysis based on genotyping studies with 17q2 microsatellites predicted that this individual was, in fact, affected by Carney complex and was at risk for development of myxomas. Further clinical evaluation and re-review of prior pathologic studies, then, confirmed the DNA-based diagnosis. This report highlights the difficulty in establishing a diagnosis of Carney complex based on clinical and pathologic findings alone, and we suggest that molecular genetic analyses provide an important diagnostic method for this familial myxoma syndrome.

Network stability from activity-dependent regulation of neuronal conductances

Activity-dependent plasticity appears to play an important role in the modification of neurons and neural circuits that occurs during development and learning. Plasticity is also essential for the maintenance of stable patterns of activity in the face of variable environmental and internal conditions. Previous theoretical and experimental results suggest that neurons stabilize their activity by altering the number or characteristics of ion channels to regulate their intrinsic electrical properties. We present both experimental and modeling evidence to show that activity-dependent regulation of conductances, operating at the level of individual neurons, can also stabilize network activity. These results indicate that the stomatogastric ganglion of the crab can generate a characteristic rhythmic pattern of activity in two fundamentally different modes of operation. In one mode, the rhythm is strictly conditional on the presence of neuromodulatory afferents from adjacent ganglia. In the other, it is independent of neuromodulatory input but relies on newly developed intrinsic properties of the component neurons.

Availability of rural Minnesota obstetric services: is it a problem?

In the late 1980s several published articles predicted a crisis in the availability of obstetric care due to declining numbers of rural obstetrical providers. Several state and national studies documented the adverse impact of malpractice and time demands on both urban and rural physicians. But only limited information is available to document current trends in rural obstetrical practice and assess whether or not the predicted crisis occurred. This study sought to provide that updated information for rural Minnesota. A telephone survey of all rural Minnesota obstetrical providers was used to document the number, location, and specialty of rural obstetrical providers, their practice limitations, and plans for future practice. This data was combined with state perinatal statistics for each county to further assess obstetrical care availability and perinatal outcomes. All rural Minnesota obstetricians and certified nurse midwives provide obstetrical care as did 69 percent of all rural family physicians. Only 27 percent of rural obstetrical providers put any type of restrictions on their obstetrical practices. During the past year, 67 currently practicing rural physicians have stopped providing obstetrical care while 55 new obstetrical providers have begun rural practice. Two to 3 percent of current rural providers plan to retire or discontinue obstetrical services during the next five years. The provider demographics from the survey identified eight counties with no prenatal providers, and 12 additional communities of decreased provider availability. However, only two of the counties with no prenatal providers and five of the counties with areas of limited providers had increased percentages of adverse prenatal outcomes such as low birthweight or late prenatal care. This study concluded that Minnesota does not have a serious statewide problem with availability of rural obstetrical providers. However, a few isolated regions of the state have limited provider availability, including limited availability of local high-risk services and consultants.

The rural health care workforce implications of practice guideline implementation

BACKGROUND

Rural health care workforce forecasting has not included adjustments for predictable changes in practice patterns, such as the introduction of practice guidelines.

PURPOSE

To estimate the impact of a practice guideline for a single health condition on the needs of a rural health professional workforce.

METHODS

The current care of a cohort of rural Medicare recipients with diabetes mellitus was compared with the care recommended by a diabetes practice guideline. The additional tests and visits that were needed to comply with the guideline were translated into additional hours of physician services and total physician full-time equivalents.

RESULTS

The implementation of a practice guideline for Medicare recipients with diabetes in rural Minnesota would require over 30,000 additional hours of primary care physician services and over 5,000 additional hours of eye care professionals' time per year. This additional need represents a 1.3% to 2.4% increase in the number of primary care physicians and a 1.0% to 6.6% increase in the number of eye-care clinicians in a state in which the rural medical provider to population ratios already meet some recommended workforce projections.

CONCLUSIONS

The implementation of practice guidelines could result in an increased need for rural health care physicians or other providers. That increase, caused by guideline implementation, should be accounted for in future rural health care workforce predictions.

Identification of a novel genetic locus for familial cardiac myxomas and Carney complex

BACKGROUND

Intracardiac myxomas are significant causes of cardiovascular morbidity and mortality through embolic stroke and heart failure. In the autosomal dominant syndrome Carney complex, intracardiac myxomas arise in the setting of lentiginosis and other lesions associated with cutaneous hyperpigmentation, extracardiac myxomas, and nonmyxomatous tumors. Genetic factors that regulate cardiac tumor growth remain unknown.

METHODS AND RESULTS

We used the molecular genetic techniques of linkage analysis to study 4 kindreds affected by Carney complex to determine the genetic basis of this syndrome. Our investigation confirmed genetic heterogeneity of Carney complex. Moreover, genetic linkage analysis with polymorphic short tandem repeats on the long arm of chromosome 17 revealed maximal pairwise LOD scores of 5.9, 1.5, 1.8, and 2.9 for families YA, YB, YC01, and YC11, respectively. Haplotype analysis excluded a founder effect at this locus. These data identify a major 17 cM locus on chromosome 17q2 that contains the Carney complex disease gene.

CONCLUSIONS

The ultimate identification and analysis of the Carney complex disease gene at this human chromosome 17q2 locus will facilitate diagnosis and treatment of cardiac myxomas and will foster new concepts in regulation of cardiac cell growth and differentiation.

Commentary: Medicaid reform issues affecting the Indian health care system

Substantial numbers of Indian people rely on Medicaid for their primary health insurance coverage. When state Medicaid programs enroll Indians in managed care programs, several unintended consequences may ensue. This paper identifies some of the perverse consequences of Medicaid reform for Indians and the Indian health care system and suggests strategies for overcoming them. It discusses the desire of Indian people to receive culturally appropriate services, the need to maintain or improve Indian health care system funding, and the duty of state governments to respect tribal sovereignty. Because of their relatively small numbers, Indians may be treated differently under Medicaid managed care systems without significantly endangering anticipated program savings. Failure of Medicaid programs to recognize the uniqueness of Indian people, however, may severely weaken the Indian health care system.

Serving rural Medicare risk enrollees: HMOs' decisions, experiences, and future plans

This article identifies factors that influence health maintenance organizations' (HMOs) decisions about offering a Medicare risk product in rural areas; describes HMOs' recent experiences serving rural Medicare risk enrollees; and assesses the potential impact of Medicare program changes on the future willingness of HMOs to offer a Medicare risk product in rural areas. Data for the analysis were collected through interviews with a national sample of 27 HMOs. The results underscore the importance of adjusted average per capita cost (AAPCC) rates in HMOs' decisions to offer Medicare risk products in rural areas, but also indicate that other factors influence these decisions.

Expanding rural managed care: enrollment patterns and prospects

This paper synthesizes national data on rural HMO enrollment in commercial plans, Medicaid HMOs and prepaid plans, and Medicare risk-based plans. Although most rural counties now are included in the service area of at least one commercial HMO, rural HMO enrollment rates are still very low. The expansion of HMO capacity to serve rural enrollees, the continued implementation of Medicaid waivers, and the recent passage of the Balanced Budget Act of 1997 with substantial Medicare program revisions suggest increased rural managed care enrollment in the future.

Understanding integrated rural health networks

In an era of constraints on public and private sector health care budgets, organizational restructuring of hospital and physician practice, and the shifting of financial risk to patients and providers, rural health professionals and communities are grappling with the issue of how to assure access to a comprehensive and affordable set of health care services. In recent years, rural health providers have turned to the strategy of developing voluntary network relations as an alternative to system or diversification strategies that entail ownership and management by one entity. A systematic analysis of the cooperative efforts of selected providers results in a proposed definition of integrated rural health networks and highlights critical aspects of their formation and development.

Mastectomy without malignancy after carcinoma diagnosed by large-core stereotactic breast biopsy

Mammary carcinoma diagnosed by large-core stereotactic biopsy (LCSBB) is often followed by definitive surgery. We report on positive (malignant) LCSBB followed by definitive surgery that failed to demonstrate malignancy. Between January 1993 and August 1996, 206 women in our institution underwent LCSBB. Carcinoma was diagnosed in 45 patients (22%) of the 206 (ductal carcinoma in situ (DCIS), n = 12; invasive carcinoma, n = 33). Twenty-nine of the 45 patients subsequently underwent mastectomy, and 8 of 45 underwent lumpectomy. In 34 (92%) of these 37 patients, carcinoma was demonstrated at follow-up surgery, but in 3 patients (8%), mastectomy failed to reveal carcinoma. The characteristics of these three patients are as follows: Patient 1 was a 58-year-old woman with a nonpalpable 6- to 8-mm nodule revealed by a screening mammogram. Three of 8 LCSBBs showed colloid carcinoma, but histologic examination of 50 paraffin blocks and radiographic examination of the mastectomy sample failed to reveal carcinoma. Patient 2 was a 64-year-old woman with a nonpalpable 6- to 9-mm nodule revealed by mammogram. Six of 12 LCSBBs showed tubular carcinoma, but histologic examination of 30 paraffin blocks from her mastectomy sample failed to reveal carcinoma. Patient 3 was a 72-year-old woman with a history of DCIS. She had undergone a lumpectomy and radiotherapy, and she had suspicious ipsilateral microcalcifications. Two of 8 LCSBBs showed comedo DCIS, but histologic examination of 26 paraffin blocks and radiographic examination of the mastectomy sample failed to reveal carcinoma. Possible explanations for a mastectomy without malignancy after carcinoma was diagnosed by LCSBB include removal of the entire lesion by LCSBB, inflammatory response obliterating remaining tumor, false-positive core biopsy result, patient misidentification, inadequate sampling of the surgical specimen, and failure to remove the tumor. We outline a series of steps for the pathologists to follow when confronted with such a case.

The dynamics of discrete-time computation, with application to recurrent neural networks and finite state machine extraction

Recurrent neural networks (RNNs) can learn to perform finite state computations. It is shown that an RNN performing a finite state computation must organize its state space to mimic the states in the minimal deterministic finite state machine that can perform that computation, and a precise description of the attractor structure of such systems is given. This knowledge effectively predicts activation space dynamics, which allows one to understand RNN computation dynamics in spite of complexity in activation dynamics. This theory provides a theoretical framework for understanding finite state machine (FSM) extraction techniques and can be used to improve training methods for RNNs performing FSM computations. This provides an example of a successful approach to understanding a general class of complex systems that has not been explicitly designed, e.g., systems that have evolved or learned their internal structure.

Risks of radiation exposure to orthopaedic surgeons

The risks of occupational radiation exposure for orthopaedic surgeons has not been well documented. The use of fluoroscopy in orthopaedics has reduced morbidity and by reducing operative time and by reducing the invasiveness of procedures. Increasingly procedures requiring the use of fluoroscopy are being developed. In a prospective study we have monitored cumulative radiation exposure over a 6-month period. The exposure levels are well below the maximum dose limits for ionizing radiation as recommended by European Economic Communities EURATOM directives. Experimentally using a phantom patient it was shown that the exposure to ionizing radiation during the insertion of a dynamic hip screw was minimal. Despite the low level of exposure care should be exercised when using fluoroscopy.

Nursing diagnosis: language antithetical to nursing's ontology

The term nursing diagnosis is constructed in male, medical language. As such, it is proposed that it has no legitimacy in nursing discourse as it is antithetical to notions claimed foremost in nursing's ontology. It is also posited that the term 'nursing diagnosis', whilst reinforcing biomedicine, has little or no meaning to many nurses, is not understood by patients and has no justifiable place in health care discourse.

Phosphorylation of the Drosophila adherens junction protein Armadillo: roles for wingless signal and zeste-white 3 kinase

The Drosophila segment polarity gene product Armadillo provides a link between two seemingly separate processes, regulation of segmental pattern by the Wingless intercellular signal and the function of cell-cell adherens junctions. armadillo was originally identified because of its segment polarity phenotype but subsequently was found to be the homolog of the vertebrate adherens junction protein beta-catenin. We examined the nature of the post-translational modification of Armadillo and its possible role in regulating Armadillo function. Armadillo is a phosphoprotein. Its level of phosphorylation varies both during embryonic development and from tissue to tissue. Phosphorylation occurs on both serine or threonine and tyrosine residues. Finally, Wingless signal negatively regulates Armadillo phosphorylation, while the segment polarity gene product Zeste-white 3, a serine/threonine protein kinase, promotes Armadillo phosphorylation. We discuss the implications of these results for regulation of Wingless/Wnt-1 signaling and adherens junction function.

The in-training examination in internal medicine

OBJECTIVE

The In-Training Examination in Internal Medicine (ITE-IM) has been offered to internal medicine trainees annually since 1988 as an instrument for self-assessment. This report outlines the manner in which the test is prepared, reviews the results of annual examinations, and analyzes trends during the past 6 years.

DESIGN

Results of each examination were reviewed with regard to the demographic characteristics of persons taking the test, their previous medical training, and their present program affiliations.

RESULTS

Then number of residents participating in the ITE-IM has increased steadily over the past 6 years. In 1993, more than 12,000 residents from more than 90% of internal medicine training programs in the United States participated in the examination; the percentage of international medical school graduates taking the examination increased from 27% in 1988 to 47% in 1993. Statistical analyses of each examination have shown it to be reliable, internally consistent, and discriminating. Over the past 6 years, graduates of U.S. medical schools have scored consistently higher than those of international medical schools and schools of osteopathic medicine on all annual examinations. However, in 1993, for residents at all levels of training, the differences in scores between graduates of U.S. medical schools and graduates of international medical schools narrowed substantially. From 1988 to 1993, there has been a trend toward lower scores by every cohort on each subsequent examination. The decreases in scores are most pronounced for graduates of U.S. medical school and those of schools of osteopathic medicine. The lower scores may be caused by either an increased level of difficulty in the examination or decreased knowledge among examinees.

CONCLUSIONS

The ITE-IM is a useful instrument to assess the knowledge base of residents and program directors with a reliable evaluation of themselves and their programs in comparison to their national peer groups. It also provides objective data to monitor trends over time in residents' scores and relates them to the changing demographic characteristics of trainees and to innovations in the clinical curricula of internal medicine training programs.

Health assessment and the nursing process: a means to an end?

The content and process of teaching health assessment coupled with the nursing process gathers momentum because it is consistent with health policy based on the principles of economic rationalism, and it covertly perpetuates positivist medical discourse while overtly postulating the emancipatory nature of adopting such practices.

Technical note: room shielding requirements in diagnostic radiology

New regulations propose a more stringent limit to the radiation exposure of workers and members of the public. The shielding in X-ray areas will have to be reassessed to take account of these new limits. This technical note identifies a computerized technique for evaluating shielding requirements which yields results that are significantly more cost effective than those determined by traditional methods.

wingless signal and Zeste-white 3 kinase trigger opposing changes in the intracellular distribution of Armadillo

wingless/wnt-1 signaling directs cell fate during development. Genetic analysis in Drosophila identified genes that may encode components of the wingless signal transduction system. Drosophila Armadillo, homolog of vertebrate beta-catenin, is required for wingless signaling. Unlike armadillo RNA, Armadillo protein accumulates non-uniformly in different cells of each embryonic segment. We found that cells alter their intracellular distribution of Armadillo in response to Wingless signal, accumulating increased levels of cytoplasmic Armadillo relative to those of membrane-associated protein. Levels of cytoplasmic Armadillo are also regulated by Zeste-White 3 kinase. Analysis of double mutants demonstrates that Armadillo's role in wingless signaling is direct, and that Armadillo functions downstream of both wingless and zeste-white 3. We present a model for the role of Armadillo stripes in transduction of wingless signal.

Intestinal bile acid malabsorption in cystic fibrosis

This study aimed at examining the mechanisms participating in excessive faecal bile acid loss in cystic fibrosis. The study was designed to define the relation between faecal fat and faecal bile acid loss in patients with and without cystic fibrosis related liver disease; to assess terminal ileal bile acid absorption by a seven day whole body retention of selenium labelled homotaurocholic acid (SeHCAT); and to determine if small intestinal bacterial overgrowth contributes to faecal bile acid loss. The study population comprised 40 patients (27 men; median age 18 years) with cystic fibrosis (n = 8) and without (n = 32) liver disease and eight control subjects. Faecal bile acid excretion was significantly higher in cystic fibrosis patients without liver disease compared with control subjects (mean (SEM) 21.5 (2.4) and 7.3 (1.2) micromoles/kg/24 hours respectively; p < 0.01) and patients with liver disease (7.9 (1.3) micromoles/kg/24 hours; p < 0.01). No correlation was found between faecal fat (g fat/24 hours) and faecal bile acid (micromoles 24 hours) excretion. Eight (33%) of cystic fibrosis patients had seven day SeHCAT retention < 10% (normal retention > 20%). SeHCAT retention in cystic fibrosis patients with liver disease was comparable with control subjects (30.0 (SEM) 8.3% v 36.8 (5.9)%; p = NS) while SeHCAT retention in cystic fibrosis patients who did not have liver disease was significantly reduced (19.9 (3.8); p < 0.05). Although evidence of small bowel bacterial overgrowth was present in 40% of patients no relation was found between breath hydrogen excretion, faecal fat, and faecal bile acid loss. The results are consistent with the presence of an abnormality in terminal ideal function in patients with cystic fibrosis who do not have liver disease and that a defect in the ileal absorption of bile acids may be a contributory factor to excessive faecal bile acid loss. Faecal bile acid loss in cystic fibrosis is unrelated to the presence of intraluminal fat or intestinal bacterial overgrowth.

Clinical disease associated with Trypanosoma theileri infection in a calf in Ireland

A four-month-old calf had a clinical history of pyrexia, anaemia, weight loss and behavioural abnormality. Clinical examination revealed evidence of regenerative anaemia and a lymphocytosis which was characterised by a relatively large B cell population. The calf deteriorated clinically while under observation and its prescapular and prefemoral lymph nodes became enlarged. Examination of a blood smear revealed the presence of a large number of circulating Trypanasoma theileri. Serological examination showed the presence of the invariant, stage-specific, trypanosome surface antigen, ISG70 and antibodies against ISG70. ISG70 was first identified in the bloodstream forms of Trypanosoma brucei and has not previously been found in T theileri. Clinical recovery was associated with an increase in packed cell volume, a decrease in the levels of circulating anti-ISG70 antibodies and the complete disappearance of circulating ISG70.

Exercise-related potassium and free fatty acid level changes in coronary artery disease. Responses after moderate intensity training

Exercise produces changes in circulating levels of potassium and free fatty acids which may provoke arrhythmias in patients with coronary artery disease. Twenty patients participating in 6 weeks of training were studied; 9 of these patients took part in 4 more weeks of training and a third exercise test. After 6 weeks, potassium levels were higher at submaximal levels of exercise, free fatty acid levels were reduced at rest, and at 5, 15, and at 30 min post-exercise. Norepinephrine levels were reduced at submaximal work loads after 6 weeks and increased at maximal work loads. The extra 4 weeks had no additive effect on these metabolic changes. Participation by coronary artery disease patients in a short-term, moderate intensity, exercise training program increases potassium levels at submaximal work loads and reduces levels of free fatty acids at rest and after exercise. The arrhythmogenic relevance of these findings deserves further consideration.

Performance evaluation of the positron scanner ECAT EXACT

The Cologne Special is a prototype of the ECAT EXACT (model 921), a new generation of Siemens-CTI PET scanners. It consists of three rings of 48 BGO block detectors each, covering an axial field of view of 16.2 cm with a patient port of 56.2 cm diameter. This results in a total of 24 rings with 384 crystals each, giving 47 contiguous image planes in two-dimensional (2D) mode. Total system sensitivity is 216 kcps/microCi/ml for a 20 cm cylinder phantom in 2D. This increases to 1.5 Mcps/microCi/ml in 3D. Data are acquired in the stationary mode only (no wobble motion), resulting in a transaxial spatial resolution of better than 6 mm full width at half-maximum (FWHM) at the center, which degrades to 7.5 mm tangentially and 9.6 mm radially at a radius of 20 cm. Average axial resolution changes from 5.0 mm FWHM at the center to 8.1 mm at R = 20 cm. Count rate performance was investigated at different low energy discriminator settings and found to be linear up to 2.5 microCi/ml with a 20 cm phantom. The magnitude and distribution of scatter were evaluated for both septa-extended and septa-retracted conditions for a range of energy thresholds. Brain, heart, and whole-body studies with the new tomograph demonstrate the versatility of its applications without compromising on physical performance.

Biliary complications of cystic fibrosis

One hundred and four adult patients with cystic fibrosis were evaluated for the presence of liver disease as defined by abnormal liver function tests of six months' duration, histological evidence of fibrosis or cirrhosis, or the presence of portal hypertension, or both. Twenty patients fulfilled these criteria and were evaluated further for the presence of biliary tract abnormalities with biliary scintigraphy using 99Tc diisopropylphenyl-carboxymethyl iminodiacetic acid (DISIDA) and endoscopic retrograde cholangiography. Clearance of 99Tc DISIDA from the liver and biliary tree was diminished at 45 (E45) and 60 (E60) minutes in the patients with liver disease compared with those without liver disease; E45 = 37.8% and 65.8%, p less than 0.01; E60 = 48.2% and 77.5%, p less than 0.01 respectively. Serial analogue images of the extrahepatic biliary tree were consistent with common bile duct obstruction with retention of DISIDA and tapering of the common bile duct in seven of 18 patients with and two of 10 patients without liver disease. Endoscopic retrograde cholangiography showed changes consistent with sclerosing cholangitis, with beading and stricturing of the intrahepatic ducts in 12 of the 14 patients. In all 14 patients, including those in whom biliary scintigraphy had suggested obstruction, no abnormality of the common bile duct was identified. These results indicate that abnormalities of the bile ducts in patients with cystic fibrosis related liver disease are confined to the intrahepatic biliary tree and that common bile duct strictures do not contribute to either the progression or development of liver disease in these patients.

Intermediate filament expression in carcinoid tumours

Twenty-eight carcinoid tumours were stained with monoclonal antibodies to epithelial and neural related intermediate filaments. All were found to express epithelial markers, and none expressed neural markers. These results support the theory that carcinoids are of epithelial, rather than neural crest origin.

Physical characteristics of the ECAT 953B/31: a new high resolution brain positron tomograph

A high spatial resolution brain positron tomograph, the ECAT 953B/31, is presented. The machine consists of two 76.5 cm diameter rings (patient port diameter: 36 cm) made of 24 8x8 BGO detector blocks each, each block being coupled to four 1 in(2) Hammamatsu phototubes. The machine has 15 9 cmx1 mm motorized removable septa, which allows reconstruction of 31 slices 3.375 mm apart. The transaxial resolution (FWHM) in the reconstructed image (with wobbling) is 4.5 mm at center, 5.2 mm (tangential) and 5.6 mm at 10 cm from center. With septa out of the field of view (FOV), the axial resolution degrades to 5.5 mm a center and 6.3 mm at 10 cm from center. At 1 muCi/cc with a 250 keV threshold and a 12 ns coincidence window, the sensitivity is 146100 true events, the ratio of randoms to trues is 0.10, the scatter fraction is 17% and the dead-time losses are 30%. With septa out of the FOV, the sensitivity is increased by a factor 3.6, while the scatter fraction reaches 0.9. Images obtained with (18 )F-DG and H(2)(15)O in human brains and (18 )F-DOPA in a baboon brain demonstrate that the ECAT 953B/31 will be suitable for high resolution and for low count rate brain studies.

Access to hospital services in rural Minnesota

A Minnesota Department of Health study on the financial condition of Minnesota's small, rural hospitals found that at least 12 hospitals were in precarious financial condition at the start of 1989, and many other hospitals were financially vulnerable. One-third or more of Minnesota's hospitals with fewer than 50 beds had negative net income in each year from 1984 to 1987. Using a standard of 30 minutes' maximum travel time for adequate access, the study revealed that about 19,000 Minnesotans in 14 counties currently have inadequate access to hospital services. Closing rural hospitals could leave additional Minnesotans without adequate access to hospital services. Given the financial condition of Minnesota's small, rural hospitals and the importance of maintaining access to hospital services in rural communities, the state may need to provide limited hospital subsidies to ensure access in geographically isolated areas.

Glomus tumours: an immunohistochemical profile of 11 cases

We studied 11 glomus tumours immunohistochemically, with a panel of connective tissue and epithelial markers. Most tumours contained small nerve fibres located in connective tissue septae between groups of glomus cells, thus accounting for the frequent occurrence of pain associated with glomus tumours. All tumours stained positively for muscle-specific actin and vimentin. Immunostaining for high and low molecular weight cytokeratins, desmin, myoglobin, S-100 protein, neurofilaments and Factor VIII related antigen was negative. Our findings confirm and amplify the proposed smooth muscle histogenesis of glomus tumours. This immunohistochemical profile may be of diagnostic value in the differential diagnosis of atypical glomus tumours.

GFR measurement by simulating constant infusion with data acquired using a CdTe detector. A feasibility study

Conventional nuclear medicine methods for measuring glomerular filtration rate, GFR, are invalidated if the initial injection of radiopharmaceutical is tissued. An analytical method proposed by Veall and Gibbs in 1982 overcomes this difficulty but does require multiple blood samples. This paper investigates whether it is feasible to use the analytical method on data acquired with a CdTe detector system and thereby reducing to one the number of blood samples required. Synthetic data were used to investigate the effect of (a) duration of sampling (b) statistical noise and (c) non-stationarity on the GFR values derived by the Veall and Gibbs method. A sampling duration of 100 min is shown to be adequate and statistical noise is not a limiting factor. However, data fluctuations, mainly due to detector motion, do reduce the accuracy of the method. When the analytical technique is applied to data obtained using a CdTe detector on 40 patients the GFR values are similar to those derived by the conventional method (r = 0.957, Syx = 9.1 ml min-1). The technique is sufficiently attractive to warrant further studies to establish its absolute accuracy.

The prophylactic use of phenytoin during iopamidol contrast studies of the subarachnoid space

Contrast examinations of the subarachnoid space are associated with side effects including convulsions. Attention has been given to the prophylactic use of anticonvulsants. We describe a simple oral regimen using the established anticonvulsant phenytoin that can be administered to short-stay patients and that achieves effective serum and CSF concentrations. A preliminary account of this work was presented to the British Pharmacological Society in January 1984 in London.

A comparison between four simple methods for measuring glomerular filtration rate using technetium-99m DTPA

Numerous centers perform glomerular filtration rate (GFR) measurements on patients undergoing renal imaging with Tc-99m DTPA. GFR measurement, however, does involve multiple blood samples taken over a 4-hour period, and this has led to attempts to simplify the technique by reducing the number of blood samples required and hence diminish the time taken to perform the test and the inconvenience to the patient. Four different simplified techniques for measuring GFR that have been reported in the literature are compared with a reference 2 blood sample method. Three of the methods do not require any blood samples but have standard errors of greater than 20 ml/min in adults and greater than 14 ml/min in children. The other method requires one blood sample, and if this is taken at 2 hours postinjection, the standard error is 9 ml/min in adults and 5 ml/min in children. The latter method is suitable for routine use in renography when accuracy is not of paramount importance.

Semi-quantitative gallium-67 lung scanning as a measure of the intensity of alveolitis in pulmonary sarcoidosis

Gallium-67 (67Ga) lung scanning has been applied for some years in pulmonary sarcoidosis to assess the activity of the alveolitis. Interpreting the scans, however, is difficult due to the low uptake of 67Ga in the disease process relative to background activity. In this study we have measured the mean parenchymal lung activity of 67Ga and have compared the lung activity to that at three remote sites, the liver, the abdomen and the thigh. The results obtained were compared with the percentage of lymphocytes in broncho-alveolar lavage fluid. There was a very good correlation with the lung-to-thigh uptake measurements and a much poorer correlation with the lung-to-liver and the lung-to-abdomen measurements. It was observed that steroid therapy reduced dramatically the correlation between the broncho-alveolar lavage findings and the 67Ga scan measurements. The results suggest that in patients not on steroid therapy, the 67Ga lung-to-thigh measurements may be used, similarly to the broncho-alveolar lavage lymphocyte counts, to identify those with high-intensity alveolitis from those with low-intensity alveolitis.