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[131I]Metaiodobenzylguanidine (131I-MIBG) was utilized in the therapy of seven patients with medullary thyroid cancer. Treatment doses ranged from 3.7 to 11 GBq, for upto four total treatments. Six of the seven patients treated showed some response to treatment (from transient partial response to symptom palliation). Treatment was tolerated well in all patients, with minimal side-effects and no signs of hematologic radiotoxicity. These encouraging results emphasize the potential of 131I-MIBG as a form of targetted radiometabolic therapy in patients with medullary thyroid cancer.

This study used an established rabbit tumor model with squamous carcinoma to evaluate the pharmacokinetics and biodistribution of technetium-99m-(V)dimercaptosuccinic acid. A total of 54 rabbits were studied (25 with no tumor; 29 with tumor). Technetium-99m(V)dimercaptosuccinic acid had a bi-exponential blood clearance in rabbits with no tumors (28 and 325 min) and in rabbits with tumors (27 and 352 min). There was no significant difference (p greater than 0.05) in mean clearance times between the two groups and clearance appeared unaffected by tumor mass. Technetium-99m(V)dimercaptosuccinic acid had a bi-exponential cumulative urine excretion with no apparent difference in half-times between non-tumor and tumor rabbit groups (200 and 240 min, respectively). Technetium-99m(V)dimercaptosuccinic acid had a major organ biodistribution in rabbits which included bone, kidneys, bladder and the blood pool. The major route of excretion was via the urine. There was no significant difference (p greater than 0.05) in organ biodistribution between rabbits with no tumors and rabbits with tumors and there was no evidence of active uptake of technetium-99m(V)dimercaptosuccinic acid by either squamous carcinoma or inflammatory tissue.

The tumor-targeting radiopharmaceutical known as pentavalent technetium-99m-meso dimercaptosuccinic acid (DMSA) has been studied by a variety of techniques in order to elucidate its structure and chemical behavior. The radiopharmaceutical is identical with a chemically characterized sample of [99TcO(DMSA)2]- when studied by mobility methods including thin-layer chromatography, reversed-phase high-performance liquid chromatography, gel filtration, and electrophoresis. The technetium is pentavalent and coordinated by an oxo-ligand and four thiolate sulfurs of two DMSA ligands. No-carrier-added preparations consist of mixtures of three stereoisomers of the square pyramidal, mononuclear complex. The isomers arise from differing orientations of the carboxylate groups in the DMSA ligands and may be designated syn-endo, syn-exo, and anti. All three isomers are significant components of the radiopharmaceutical, raising the question of which are tumor-specific. The carboxylate groups in the complex are almost completely ionized at pH 7, thus the average charge on the complex at this pH approaches -5.

This study was undertaken to compare clinical evaluation of the neck with 99mTc(v) DMSA planar scintigraphy and computerized tomography (CT) in patients with head and neck carcinoma. Twenty-six patients were studied and in all but one the neck was previously untreated. A total of 31 neck dissections were performed and the specimens examined histopathologically. CT was approximately as accurate (71%) as clinical examination (68%) and more accurate than 99mTc(v) DMSA planar scintigraphy (48%) in predicting which necks contained metastatic carcinoma. Overall, 13% of necks had their staging correctly changed by 99mTc(v) DMSA scintigraphy compared with 10% for CT. Although scintigraphy upstaged 13% of clinically N0 necks compared to 6% for CT, it was less sensitive and specific than either clinical examination or CT. 99mTc(v) DMSA planar scintigraphy has no role to play in the investigation of patients with metastatic carcinoma to include the clinically N0 neck.

One hundred and seventy AIDS cases and 547 HIV-1 antibody positive reports of infection in persons who are presumed to have become infected by sexual intercourse between men and women abroad are reviewed. Eighty three percent of people with AIDS and 99% of HIV-1 infected persons were reported to have been exposed in countries where heterosexual spread of HIV infection is well documented (i.e. WHO patterns II or I/II - see below). African countries were commonly cited. The group that had been exposed heterosexually in pattern II or I/II countries was young, and males slightly outnumbered females. Persons who are presumed to have become infected with HIV-1 through heterosexual contact abroad make up a heterogeneous group of travellers which includes holiday makers, business persons, students, refugees and immigrants. Research is needed to identify travellers whose high risk behaviour makes them vulnerable to HIV-1 infection, and to develop effective health education measures for them.

The management of 12 patients with medullary thyroid carcinoma is reviewed. All patients underwent total thyroidectomy. Local nodal and extracapsular spread was aggressively resected, followed by radiotherapy. No patient died from uncontrolled local disease. Prolonged survival after radical treatment is demonstrated even in the presence of distant metastases.

[186Re]Re(V)DMSA, a beta-emitting analogue of the tumour imaging radiopharmaceutical pentavalent [99mTc]Tc(V)DMSA of possible value in tumour therapy, is readily prepared by stannous reduction of [186Re]ReO4 in the presence of dimercaptosuccinic acid at 100 degrees C using a commercial DMSA kit as used for renal imaging with 99mTc, and purified using a disposable sample preparation column. The complex has been identified as [ReO(DMSA)2] by NMR, optical and i.r., spectroscopy and elemental analysis.

Radionuclide therapy has a proven place in the management of patients with thyroid disease. Iodine-131 therapy has been established as both successful and safe in treating patients with thyrotoxicosis and thyroid malignancy. Protocols for patient treatment are now standardised, although some variation in practice exists across Europe. There remains much confusion as to which patients should be selected for treatment with radio-iodine for thyrotoxicosis and what dose should be administered. A review of the literature reveals that many of the theoretical hazards of treatment with radio-iodine have not been encountered despite many years of usage. New therapies for medullary thyroid cancer are now being evaluated and recent promising developments are discussed in detail.

A 69-year-old lady with previous medullary thyroid carcinoma treated by total thyroidectomy alone developed a swelling in the neck. This was thought to be a recurrence of her carcinoma but was found on investigation to be a tuberculous abscess of the thyroid bed. She was treated successfully by surgical drainage and antituberculous chemotherapy.

Technetium-99m (99mTc) (v) dimercaptosuccinic acid (DMSA) is a new tumour-imaging agent which has been used to image head and neck squamous carcinoma. This study used an established rabbit tumour model to compare palpation versus planar scintigraphy in the detection of superficially transplanted cancers. Palpation detected 83% of tumours measuring less than 2 cm compared with 58% for scintigraphy. Overall, the sensitivity for palpation was 88% (77% specificity) compared with 50% (63% specificity) for scintigraphy.

Technetium-99m (Tc99m)(v) Dimercaptosuccinic Acid (DMSA) is an imaging agent which has been proposed as a scintigraphic marker for head and neck squamous cell carcinoma. Fifty-four patients were studied of whom 51 had a head and neck tumour. All patients were examined and then imaged using Tc99m(v) DMSA scintigraphy and computerized tomography. Scintigraphy was less sensitive than clinical examination in the detection of patients with cancer, patients with primary tumours and patients with metastatic neck disease. CT was as sensitive and as accurate as clinical examination but more sensitive than Tc99m(v) DMSA in detecting patients with cancer and with primary tumours. CT was more sensitive and more accurate than both clinical examination and Tc99m(v) DMSA scintigraphy in predicting which patients had metastatic neck disease. Although Tc99m(v) DMSA is accumulated by squamous cell carcinoma, its inability to detect low volume disease and apparent low specificity means it has no role to play in the management of patients with head and neck squamous cell carcinoma.

In the light of the control of expenditure and changes in radiopharmaceutical costs, changes in study protocols, new investigation procedures and inappropriate placing in Korner categories, the BNMS Council set up a working party to derive an agreed set of costings for Nuclear Medicine techniques. Using data from three hospitals with additional information from another nine, we have agreed the 1988 cost of individual nuclear medicine procedures in the UK. These figures include staffing (radiopharmacy, nursing, physics, medical including consultant), radiopharmaceuticals and other consumables, indirect costs (secretarial, administrative, portering), variable overheads (service contracts, stationery) and fixed overheads (rates, lighting, heating, building and engineering). Capital costs, equipment and buildings were not included. Because figures include salary and overhead costs they are difficult to compare with the majority of other previous nuclear medicine costings, apart from Bretland et al., or with data for other imaging modalities. Comparison of these costings with Korner schedules shows marked overlap between the Korner groups. Such groups therefore form a poor method of costing nuclear medicine procedures. We propose alternative groupings.

Technetium-99m(99Tcm) (V) dimercaptosuccinic acid is a new imaging agent which has been used to evaluate head and neck squamous cell carcinoma (SCC). This study compared the subcellular biodistribution of 99Tcm(V)DMSA in an established rabbit tumour SCC model and in humans with head and neck SCC. In rabbits, approximately 17-37% of radioactivity was located on tumour cell membrane. Approximately 57-80% of radioactivity was located nonspecifically in tumour cytosol, only 2-6% was bound specifically to tumour mitochondria, and 1-4% bound specifically to microsomes. In humans, 25-45% of radioactivity was localized on tumour cell membrane and 28-60% localized nonspecifically in tumour cytosol. There was 11-20% of radioactivity specifically bound inside the cell to the mitochondria and 1-6% specifically bound to microsomes. These results show that although 99Tcm(V)DMSA is accumulated at sites of SCC, the localization process is nonspecific.

Technetium-99m (99Tcm)(V) dimercaptosuccinic acid (DMSA) is a new tumour imaging agent which has been used to evaluate squamous carcinoma (SCC) of the head and neck. This study evaluated the pharmacokinetics and biodistribution of 99Tcm(V)DMSA in patients with SCC and calculated the bone mass of a New Zealand White (NZW) rabbit. This data was then used to calculate the effective dose equivalent in man. A total of 16 patients were studied (5 with no tumour, 11 with tumour). 99Tcm(V)DMSA had a fast bi-exponential blood clearance in patients with no tumour (30 and 401 min) and patients with tumour (30 and 387 min) with no significant difference (p greater than 0.05) between the two groups. 99Tcm(V)DMSA had a fast cumulative urine excretion with mean half-times in non-tumour and tumour patients of 183 min and 244 min respectively. There was no significant difference (p greater than 0.05) between these two latter groups. The effective dose equivalent of 99Tcm(V)DMSA in man is 5.1 microSv/MBq.

Technetium-99m (99Tcm) (v) dimercaptosuccinic acid (DMSA) is a new tumour imaging agent which has been used to evaluate head and neck tumours. It has a normal head and neck biodistribution to include the lacrimal glands, nasal mucosa and the blood-pool. Seventy-seven patients were studied of whom 63 had a head and neck malignancy. Of these patients, 19 (25%) exhibited positive accumulation of radioactivity in the region of the pituitary gland and this was a constant finding in those followed-up after treatment. Biodistribution studies in forty New Zealand white rabbits confirmed pituitary accumulation of 99Tcm (v) DMSA. The pituitary gland region should be included in the normal biodistribution of 99Tcm (v) DMSA.

Technetium-99m (99Tcm) (v) dimercaptosuccinic acid (DMSA) is a new tumour imaging agent which has been used to image medullary carcinoma of the thyroid and squamous cell carcinoma (SCC) of the head and neck. This study was undertaken to compare planar scintigraphy in patients with head and neck SCC using 99Tcm (v) DMSA and the established tumour imaging agent gallium-67 citrate (67Ga). Seventeen patients were studied of whom 16 had a head and neck malignancy. Clinical examination was more sensitive and accurate than 67Ga scintigraphy, which in turn was more sensitive and accurate than 99Tcm (v) DMSA in detecting patients with cancer, patients with primary tumours and patients with metastatic neck carcinoma. Neither 67Ga or 99Tcm (v) DMSA planar scintigraphy has any role to play in the routine evaluation at presentation of patients with head and neck SCC.

Technetium-99m (99Tcm) (v) dimercaptosuccinic acid (DMSA) is a new tumour imaging agent which has been used to image squamous cell carcinoma (SCC) of the head and neck. This study was undertaken to compare planar versus SPECT 99Tcm (v) DMSA scintigraphy in patients with head and neck SCC. Thirty-four patients were studied. Twenty-eight had SCC, and of these, four had received previous treatment with surgery or irradiation. SPECT was as sensitive and as accurate as clinical examination (but more sensitive and accurate than planar scintigraphy) in detecting which patients had cancer and which patients had primary tumours. SPECT was more sensitive and more accurate than planar scintigraphy (but less sensitive and accurate than clinical examination) in detecting lateral neck compartments with metastatic carcinoma. SPECT correctly upstaged 6% of clinically N0 necks. Although SPECT 99Tcm (v) DMSA scintigraphy improved the image quality, sensitivity and spatial resolution of the investigation, it has no role to play in the routine evaluation of patients with head and neck SCC (to include the clinically N0 neck).

We report our experience using [131I]metaiodobenzylguanidine (MIBG) to image nine patients with proven medullary carcinoma of the thyroid (MCT). Positive uptake was seen in four patients, equivocal uptake in one patient, and no uptake in four patients. Data is presented to demonstrate the pharmacokinetics of [131I]MIBG in three of the patients studied. Two patients, with diarrhea and severe pain from known bone metastases and positive uptake on [131I]MIBG diagnostic scanning, subsequently received therapeutic doses of [131I]MIBG, with marked improvement in both pain and diarrhea, but no evidence of significant biochemical response. Iodine-131 MIBG uptake in patients with MCT is variable, and gives a higher false-negative rate than is found when using [131I]MIBG to image other neuroectodermally derived tumors. The therapeutic potential of [131I]MIBG in patients with MCT warrants further evaluation, in view of the symptomatic relief experienced following therapy doses in two patients with extensive disease.

Production records of crossbred ewes, including weight at mating (WTM), fertility (FRT), number of lambs born per ewe lambing (BRN), number of lambs weaned (WEN), litter weight in April (WTA) and litter weight at weaning (WTW), were analyzed for the estimation of breed differences, genotype x environment interactions and repeatability and heritability of ewe production. All ewes were from Suffolk- or Columbia-type dams. Breed of sire of ewe was Finnsheep, Dorset, North Country Cheviot or Romney, Suffolk-cross (SX) ewes were heavier at mating than Columbia-cross (CX) ewes. Cheviot-cross (NX) and Finnsheep-cross (FX) ewes were the most fertile on hill pastures, while Dorset-cross (DX) ewes were the most fertile on irrigated pastures. The FX ewes had larger litters at birth and at weaning. Columbia-cross ewes had larger litters than SX ewes on hill pastures, but the SX ewes had larger litters than CX ewes on irrigated pastures. Finnsheep-cross ewes on both types of pastures and DX ewes on irrigated pastures had heavier litter weights than NX or Romney-cross ewes at weaning. Repeatability estimates for WTM, FRT, BRN, WEN, WTA and WTW were .61, .15, .19, .08, .07 and .09, respectively. Heritabilities, from the sire-of-ewe component, were .40, .02, .12, .0, -.02 and -.05 for WTM, FRT, BRN, WEN, WTA and WTW, respectively.

A new imaging agent, Technetium-99m (Tc99m) (v) Dimercaptosuccinic acid (DMSA), has recently been developed which has been used to evaluate head and neck tumours. Twenty-four patients were studied of whom 21 had histologically proven SCC of the head and neck. The remaining 3 had benign lesions. Planar imaging of patients with primary disease revealed a sensitivity of 83% and a 75% specificity. The results of planar imaging of patients with cervical metastases yielded a 92% sensitivity and 100% specificity. Seven patients also had single photon emission computerized tomography (SPECT) which improved the image quality, spatial resolution and sensitivity of the investigation. Tc99m (v) DMSA imaging provides a cheap and rapid means of investigating head and neck SCC. This study suggests further work is indicated to assess its role in diagnosis and subsequent management.

In order to assess the role of 99Tcm pentavalent dimercaptosuccinic acid (99Tcm (V)DMSA) scanning in the management of patients with medullary carcinoma of the thyroid, we imaged 10 patients with histologically proven disease. Nine of the 10 patients were scanned after removal of the primary tumour, but with symptomatic or biochemical evidence of recurrence. One patient was imaged prior to thyroidectomy. In eight of the 10 patients 99Tcm(V)DMSA successfully identified tumour deposits, and it has been shown in this study to be a cheap, convenient radiopharmaceutical for studying this group of patients, producing high-quality images with low radiation doses, and contributing significantly to patient management.

Accidents are the leading cause of death in infancy and childhood from ages one through 24. Parental training programs in the prevention and management of pediatric emergencies may effectively decrease the morbidity and mortality of sudden accidental death in children. The Heartsaver-Baby course is a course in cardiopulmonary resuscitation specifically designed for young parents. It includes training in the prevention of childhood emergencies resulting in sudden death, recognition of the most common emergencies in different age groups, practical training in CPR and obstructed airway maneuvers. Widespread implementation of this community program may help decrease the incidence of accidents in children and provide parents with a better background to deal with life-threatening emergencies.

Right ventricular (RV) function was assessed in 80 patients with congenital heart disease by first-pass and gated equilibrium radionuclide angiography. In 30 patients with a ventricular septal defect (VSD) the mean RV ejection fraction (+/- standard deviation) was 64 +/- 7%. In 30 patients with a secundum atrial septal defect it was 61 +/- 9% and in 20 patients with surgically corrected complete transposition of the great arteries it was 49 +/- 13%. These values are in close agreement with values established with cineangiography for similar groups of patients. The mean ejection fraction in the group with transposition of the great arteries was significantly less than in the group with VSD (p less than 0.001). Phase analysis of the equilibrium studies showed that there was delayed RV contraction in many patients in the absence of conduction abnormalities. This delay was significantly greater in patients with atrial septal defect than in those with VSD (p less than 0.05). There was a strong correlation between size of left-to-right shunt and phase delay in patients with VSD (r = -0.72). Thus, first-pass gated radionuclide angiography provides a valid measurement of RV ejection fraction, and delayed RV contraction on phase analysis may be a sensitive index of early RV dysfunction.

A recently developed imaging agent, technetium-99m (v) dimercaptosuccinic acid (99mTc (v) DMSA), has been used to assess head and neck squamous carcinoma (SCC). We have prospectively studied 62 patients of whom 53 had a histologically proven head and neck SCC. The remaining nine had benign lesions. The results of planar imaging in patients with primary disease yielded an 85% sensitivity and 78% specificity. Planar imaging in patients with cervical lymphadenopathy revealed a 59% sensitivity. Nineteen patients also had single photon emission computed tomography imaging which improved the image quality, spatial resolution and sensitivity of the investigation. Twenty-seven patients were scanned before and after radiotherapy and, of these, 96% showed positive uptake in the salivary glands with no evidence of tumor recurrence. This study has shown 99mTc (v) DMSA imaging provides a cheap and rapid method of investigating head and neck SCC and further studies are necessary to evaluate its role in the management of patients with this disease.

Thirty-two patients with suspected coronary artery disease were studied by single photon emission computed tomography (SPECT) imaging with oblique reconstructions of the myocardium following the intravenous administration of technetium-99m methoxy isobutyl isonitrile at peak exercise. All patients also underwent three-vessel coronary angiography. The SPECT technique produced very detailed images allowing easy delineation of localized myocardial defects. Segmental myocardial uptake defects were compared with diseased vessels as shown at angiography. A good correlation was shown between right coronary artery (RCA) disease and mid and proximal inferior segments and between left circumflex (LCx) artery disease and mid and proximal lateral segments, allowing accurate localization of a defect to one of these two vessels' territories. Sensitivity and specificity of detection of disease of the RCA and LCx artery were high. Defects associated with a lesion of the left anterior descending vessel were more variable.

99mTc diphosphonate bone scanning has proved to be a sensitive, though nonspecific, way of detecting a wide variety of metabolic bone disorders. Classic scan appearances of generalized increased tracer uptake throughout the skeleton are found in many types of metabolic bone disease, and whole-body retention measurements can be used to detect early forms of disease. Focal disease identified on bone scanning such as pseudofractures and brown tumors are clearly identified on the 99mTc diphosphonate bone scan, with isotope scan changes preceding radiological changes by up to 18 months. The use of whole-body retention measurements will further increase sensitivity of detection in patients with metabolic bone disease.

Nine patients with histologically proven medullary carcinoma of the thyroid (MCT) were imaged using pentavalent [99mTc]dimercaptosuccinic acid [(V)DMSA], [131I] metaiodobenzylguanidine (MIBG) and [99mTc]methylene diphosphonate (MDP). Technetium-99m (V)DMSA demonstrated most of the tumor sites in eight patients with proven metastases, with an overall sensitivity of 95% in lesion detection. Iodine-131 MIBG showed definite uptake in some of the tumor sites in three of the nine patients imaged, with equivocal uptake seen in a further one patient, with sensitivity of only 11% for lesion detection. Technetium-99m MDP demonstrated bony metastases only, in four of the patients imaged yielding a sensitivity of 61%. Technetium-99m (V)DMSA has been demonstrated in this study to be a useful imaging agent in patients with MCT, showing uptake in significantly more lesions and with better imaging qualities than [131I]MIBG, and with the ability to detect soft tissue as well as bony metastases.

1. Both phenobarbital and clofibrate pretreatment cause a qualitative change in cytochrome P-450 content in housefly (Musca domestica). Based on changes in substrate specificity, both inducing agents appear to cause induction of an isoenzyme (or group of isoenzymes) of cytochrome P-450 in housefly, and this response is similar in extent and effect to that described in rodents. 2. Using Western blot analysis and probing with antibodies to three rat hepatic isoenzymes (P450 IA1, P450 IIB1 and P450 IVA1), common structural epitopes with housefly cytochrome P-450 were sought. Despite similarities in patterns of induction and catalytic function, little evidence for structural commonality between the cytochrome P-450 in rat and housefly was observed.

99Tcm-(V)-DMSA is a new tumour imaging agent which has been used to image squamous cell carcinoma (SCC) of the head and neck. There have been, however, no studies to date evaluating its optimal imaging time for SCC. Seven patients were studied (six SCC; one nontumour) and seven rabbits (six with SCC, (17 tumours); one nontumour). For the human qualitative studies there was a 67% sensitivity at 2, 4 and 6 h with image quality being optimum at 4 h. Maximum quantitative uptake occurred between 2 and 4 h. For the rabbit qualitative studies the optimum imaging time was 4 h (92% sensitivity, 100% specificity) and maximum quantitative uptake occurred at between 1.5 and 5 h. Taking into account the human and rabbit qualitative and quantitative studies combined with the pharmacokinetics and biodistribution of 99Tcm-(V)-DMSA, the optimum imaging time of 99Tcm-(V)-DMSA in humans with SCC was between 2 and 4 h.

The results of an intensive 12 months study of a number of herds in the migratory and sedentary sectors of the livestock economy of Southern Darfur are recorded. In almost every production parameter the performance of the former is superior to that of the latter but, overall, production appears to be static or declining. During 1973 the cattle population of the area is estimated to have declined 7 per cent. Meat production per kilogramme of breeding female was calculated to be 0-057 kg in the migratory sector but only 0-023 kg in the sedentary sector. Calculated calving rates are significantly higher at 65 per cent in the migratory sector than the 40 per cent of the sedentary sector. Deaths in the former sector were only 15 per cent compared with the 35 per cent of the latter. It is concluded that total settlement of the migratory sector is not the answer to the current problem of the livestock sector of Southern Darfur.

Growth of Anabaena sp. strain 7120 (in the absence of chelators or added iron) was inhibited by the addition of 2.1 to 6.5 microM copper and was abolished by copper concentration of 10 microM or higher. When the copper was chelated to schizokinen (the siderophore produced by this organism in response to iron starvation), the toxic effects were eliminated. Analysis of culture filtrates showed that the cupric schizokinen remains in the medium, thereby lowering the amount of copper taken up by the cells. Although this organism actively transports ferric schizokinen, it apparently does not recognize the cupric complex. Thus, Anabaena sp. is protected from copper toxicity under conditions in which siderophore is being produced. For cells grown in low iron, the accumulation of extracellular schizokinen was observed to parallel cell growth and continue well into stationary phase. The actual iron status of the organism was monitored by using iron uptake velocity as an assay. Cultures grown on 0.1 microM added iron were found to be severely iron limited upon reaching stationary phase, thus explaining the continued production of schizokinen. These data show that the siderophore system in Anabaena spp. has developed primarily as a response to iron starvation and that additional functions such as alleviation of copper toxicity or allelopathic inhibition of other algal species are merely secondary benefits.

Bone scans were reviewed in 478 patients, 237 with carcinoma of the breast, 47 with carcinoma of the lung, 43 with carcinoma of the prostate, 56 with other malignancies and 95 in whom scans were performed for basic screening purposes. In only 11 of the scans reviewed were abnormalities of the skull alone observed and in only one of the 11 scans was the finding of an abnormality thought to be clinically useful. This study suggests that in patients with known malignant disease, the skull view adds little useful information. However, when performing bone scans for screening purposes, the skull view may well give helpful information.

We have reviewed our experience over the past 5 years of 32 thyroid scans in Hashimoto's thyroiditis. A wide variety of images were obtained, the most common finding being that of an enlarged gland with diffusely increased tracer uptake, a pattern identical to that found in Graves' disease (eight patients). Of the remainder, four scans were normal, four showed an enlarged gland with normal tracer uptake, five a multinodular gland with normal tracer uptake, five a multinodular gland with high tracer uptake, five a single non-functioning nodule and in one patient there was low tracer uptake by the gland. It is apparent that the thyroid scan in Hashimoto's thyroiditis can mimic a wide range of thyroid disorders. Thus, taken in isolation, the scan findings can be misleading and should be evaluated in conjunction with current biochemistry.

99Tcm(v)-DMSA is a new tumour-imaging agent which has recently been proposed as a scintigraphic marker for head and neck squamous cell carcinoma (SCC). Seventy-seven patients were studied prospectively, of whom 58 had a history and diagnosis of head and neck SCC. All patients were examined, imaged using 99Tcm(v)-DMSA planar scintigraphy and then followed up clinically. In addition, 35 patients were followed up with scintigraphy (81 studies). Scintigraphy was less sensitive and less accurate than clinical examination for the overall detection of patients with SCC, for the detection of patients with SCC at presentation and for the detection of patients with primary tumours, possible nodal disease and with residual and recurrent disease following surgery and irradiation. Approximately 50% of patients exhibited positive uptake of 99Tcm(v)-DMSA in the salivary glands following radiotherapy. Although 99Tcm(v)-DMSA is accumulated at sites of head and neck SCC, its inability to detect low volume disease and apparent low specificity following surgery and irradiation means it has no role to play in the routine evaluation of patients with head and neck SCC.

Cytochrome b5 was purified to electrophoretic homogeneity from the liver microsomes of untreated rats and reincorporated into liver microsomes from phenobarbital-treated rats, resulting in an approximate three-fold enrichment of the cytochrome b5 specific content (1.5 nmol haemoprotein X mg-1 protein). Our results have shown that the N-demethylation of benzphetamine was progressively inhibited in cytochrome b5-fortified microsomal preparations. Using stopped flow, visible difference spectrophotometry, the NADPH-driven reduction kinetics of cytochrome P-450 were examined in the modified microsomes over the first few seconds of reaction. Increasing the amount of incorporated cytochrome b5 resulted in a progressive inhibition of the initial, fast phase reduction rate constant of microsomal cytochrome P-450, both in the absence and presence of the type I substrate benzphetamine. Although the initial rate of NADPH-driven cytochrome b5 reduction was the same for both native and cytochrome b5-fortified microsomes, the extent of cytochrome b5 reduction was greater in the fortified microsomes. If cytochrome b5 has a positive role to play in cytochrome P-450-dependent mixed function oxidase activity either as an effector or in electron transfer or both, the former haemoprotein must be already present in sufficient concentrations in the native microsomes.

The clinical usefulness of detecting abnormal movement of the posterior wall of the aortic root by M-mode echocardiography was studied in 93 patients with common cardiac diseases (mitral and aortic valve disease, atrial septal defect, hypertrophic and congestive cardiomyopathy) and in 17 normal subjects. Though abnormally slow (less than 3 cm/s) or prolonged (greater than 240 ms) diastolic movement was confirmed to be common in mitral stenosis, since it occurred in 35 of 36 patients it was non-specific. Similar abnormalities frequently occurred in other patients with, for example, mitral regurgitation, aortic valve disease, after aortic valve replacement, and in both hypertrophic and congestive cardiomyopathy. The severity of mitral stenosis, assessed at operation, could not be accurately predicted from abnormalities of aortic root movement. Information derived from aortic movement was not diagnostic and did not predict severity in isolated mitral regurgitation though both the peak rate of systolic aortic motion and total aortic excursion were significantly greater than normal. We conclude that abnormalities of posterior aortic wall movement are frequent and their specificity and clinical usefulness are limited.