Watery diarrhoea in medullary carcinoma of the thyroid occurs in up to 30% of cases and may respond to removal of tumour tissue (Williams, 1966; Bernier et al., 1969). Previous clinical studies have shown abnormalities of small bowel motility and fluid and electrolyte absorption (Bernier et al., 1969; Isaacs et at., 1974). Among the substances elaborated by the tumour which could cause diarrhoea, prostaglandins and calcitonin are suggested causative agents. Raised blood and tumour prostaglandins have been found in some patients, and prostaglandins can produce diarrhoea in man and experimental animals (Williams et al., 1968; Cummings et al., 1973). Prostaglandins activate the adenyl cyclase/cAMP mechanism, leading to net intestinal fluid secretion. In contrast, calcitonin is invariably raised in medullary carcinoma (Melvin et al., 1972). It is also a potent secretagogue in both human and rabbit small intestine (Kisloff and Moore, 1977; Gray et al., 1975), but its mechanism of action is unknown. In order to determine the mechanism of diarrhoea in a patient suffering from this tumour, we first measured plasma levels of hormones known to alter intestinal fluid transport. Secondly, distal ileal flow was monitored, as an index of net fluid absorption in the small intestine. The cyclic AMP levels in the patients' small bowel mucosa were also measured. Finally, the diarrhoeagenic factor in the patient's plasma was studied by bioassay in the dog small intestine.

Research into the in-plane vibration properties of rotating tyre-wheel-hub assemblies involved the need to measure accurately small variations in the substantially larger angular velocity of an automotive wheel hub. Straightforward application of a tachogenerator to the task would have been subject to the classic measurement difficulty that the variable of interest was the small difference between two large quantities. The necessary accuracy would not have been achievable. The test wheel assembly was an automotive type, deriving from a vehicle fitted with anti-lock brakes. It was fitted with a toothed ring and variable reluctance proximity sensor in its standard form. A method for using this sensor's output to derive information on the wheel spin velocity variation was derived. The method used and its proof by simulation and by experimentation are described.

A study of the small in-plane vibrations of a tyre and suspension system is reported. A laboratory rig, a measurement system, data processing, a mathematical model and parameter identification procedures are described. Results demonstrate good agreement between the model, based on a rigid ring representation of the tyre with a linear force/slip law and test results from the laboratory. The test results are repeatable and show system linearity, as indicated by high coherences. Model results are used to generate suspension system responses to road velocity variation forcing, for different mean road speeds. It is argued that these results are useful for suspension design and trouble shooting purposes.

The rate constant (α2) of the terminal exponential of the technetium-99m diethylene triamine pentaacetic acid (DTPA) plasma clearance curve is close to the ratio of glomerular filtration rate (GFR) to extracellular fluid volume (ECV) and is therefore a convenient, already normalised, measure of filtration function. Sinceα2 depends on the distribution volume of the tracer, our aim was to compareα2 from inulin and99mTc-DTPA and also to compare the equilibration kinetics of the two filtration markers. Fifty millititres of99mTc-DTPA (250 MBq) and inulin (10%), mixed in the same syringe, were given by intravenous injection in 15 patients undergoing routine99mTc-DTPA renography for a variety of clinical indications. Frequent antecubital venous blood samples were taken up to about 4 h after injection to construct plasma clearance curves from which GFR, ECV and GFR/ECV (i.e. the reciprocal of mean transit time through the distribution volume) were calculated.99mTc-DTPA/inulin concentration ratio curves were also constructed after normalisation to the ratio in the syringe. GFR given by the two markers correlated closely (DTPA=0.98·inulin—0.4ml/min;r=0.98).99mTc-DTPA had the same distribution volume as inulin, had a similar transit time through it and gave the same value ofα2 (r=0.98). GFR/ECV from99mTc-DTPA accordingly correlated closely with GFR/ECV from inulin (DTPA=0.75·inulin+0.99 ml/min;r=0.95). Even though the distribution volumes and the times to equilibration (i.e. to reach the terminal exponential) were similar, the distribution volume of99mTc-DTPA at about 10 min after injection was, after subtraction of the plasma volume, about twice that of inulin.We confirm the validity of99mTc-DTPA for measuring GFR.α2 is a convenient measure of GFR, can be based on the terminal exponential of inulin of99mTc-DTPA curves and can be converted to GFR/ECV with an appropriate scaling factor. The kinetics or the two clearance curves with respect to anatomical correlates of the exponentials and the rates of diffusion throughout the respective distribution volumes requires further study.

Therapeutic embolization is an established technique in interventional radiology. In our unit we have considerable experience in the use of this technique in the management of systemic arteriovenous malformations. During the embolization of systemic vascular lesions containing arteriovenous communications, there is a danger of embolic material being swept into the venous side of the circulation and causing pulmonary embolism. In a previous study of 137 patients treated in this way, overt pulmonary embolism was observed to occur in two patients (1.5%); we did not, however, determine the incidence of subclinical embolism in that series and are unaware of any other available data concerning this (Hemingway & Allison, 1988).

Hepatic portal venous gas is an entity frequently associated with a sinister outcome in infantile necrotizing enterocolitis, small bowel infarction and intra-abdominal sepsis (Sisley et al, 1987). A recent case report described its occurrence in a patient receiving monoclonal antibody therapy (Waymack et al, 1987). We describe a case in which portal venous gas appeared secondary to therapeutic embolization of the hepatic artery, a phenomenon which, to our knowledge, has not been reported previously. The diagnosis was made by computed tomography (CT) and the gas remained in the portal system for at least 8 days. A 22-year-old male patient was referred from another hospital following a road traffic accident 2 weeks previously. Laparotomy immediately after the accident had revealed two deep lacerations in the right lobe of liver which were controlled by suturing and drainage. Post-operatively the patient had a persistent pyrexia followed 2 weeks later by melaena and haematemesis associated with hypotension and right hypochondrial pain.

Digital subtraction angiography (DSA) was used in the investigation, by dynamic cavernosography, of 35 men with acquired erectile impotence. The benefits of using DSA included shorter examination times, lower contrast medium dosage and better definition of abnormal veins. In particular deep crural veins are more clearly seen than in conventional studies and these may be of more importance than was previously thought.

AbstractIn patients with a bleeding disorder or coagulopathy who require liver biopsy, conventional liver biopsy has a high risk of uncontrollable hemorrhage. Biopsy in such cases has been performed via the transjugular approach that, although safe, is technically challenging, requires cardiac monitoring and may have a small specimen volume.An alternative, safe, and more direct method of obtaining histological samples is by Trucut liver biopsy followed by embolization of the biopsy track. This may leave behind a track that on sonographic examination may simulate other pathology.

A patient with a 10-year history of episodes of venous thrombosis, a high ESR, an elevated plasma polyclonal 1gG concentration, and bleeding from esophageal varices had obstruction of both superior and inferior vena cavas with "downhill" esophageal varices and a normal portal vein with normal portal pressure. Extensive investigations revealed no predisposing factor for the venous thromboses, but the patient made a good clinical response to steroids and dapsone, with no further episodes of bleeding nor evidence of major venous thrombosis. The causes and outcome of "downhill" varices are discussed.

Large arteriovenous malformations frequently require surgical excision in order to prevent or treat the potentially serious problems they can cause ranging from haemorrhage and pain to cardiac failure. The surgery itself is usually difficult and often dangerous due to the serious risk of major intraoperative haemorrhage. Transcatheter arterial embolisation has greatly facilitated the management of small arteriovenous malformations but may only afford temporary relief of symptoms in very large lesions. Recanalisation of occluded vessels and revascularisation via previously insignificant collateral vessels means that large lesions cannot be effectively managed by this method alone. Previous surgery and ligation of feeding vessels may make effective embolisation difficult or impossible and a combined radiological and surgical approach to these lesions may permit definitive treatment. We present three cases in whom the pre-operative embolisation of buttock arteriovenous malformations facilitated successful surgical excision.

Surgical removal of a large carotid body tumour can be difficult and hazardous because the tumours are extremely vascular. We present a case in which preoperative embolisation of such a tumour facilitated subsequent surgery. The case also illustrates a technique for protecting vascular territories outside the embolisation field from inadvertent embolisation.

Vesico-vaginal fistula with its associated incontinence is an unpleasant and distressing condition and when it occurs as a result of pelvic malignant disease, surgical management can be very difficult. We describe a case in which percutaneous transrenal embolisation of the ureter abolished the incontinence and obviated the need for further surgery. The technique has been used successfully in a previous similar case (Gunther et al, 1979). A 68-year-old woman was found to have an endometrial carcinoma in 1980. The tumour had already invaded locally into the pelvis and the initial treatment consisted of surgical removal of as much malignant tissue as possible. One year later she returned with evidence of extensive local recurrence for which she received pelvic radiotherapy. She remained symptom-free until 1983 when she presented with incontinence due to a vesico-vaginal fistula. There was clinical evidence of further pelvic tumour and an intravenous urogram showed no function in the right kidney, a normal left kidney and ureter and extravasation of contrast medium from the bladder to the vagina (Fig. 1). At laparotomy the recurrence of her carcinoma was deemed inoperable, so both ureters were ligated and the next day a percutaneous catheter nephrostomy of the left kidney was performed in the radiology department. Satisfactory urinary drainage was established and the patient was discharged five days later with no evidence of urinary incontinence.

Four patients with large right upper quadrant tumour masses of non-hepatic origin are presented. On initial clinical and radiological assessment, all cases were misinterpreted as either having a primary liver tumour or extensive invasion of the liver by an extrinsic tumour. Although angiography and CT scanning are most likely to yield an accurate diagnosis, they can be misleading. Vena cavography also gives important information in determining operability and at operation guides the retroperitoneal dissection. After thorough investigation an aggressive surgical approach to these tumours, with hepatic resection when necessary, provides the best chance of good palliation and possible cure.

Summary: A case of progressive venous thrombosis involving the superior vena cava is reported following implantation of a permanent transvenous pacemaker. Acute symptoms in the arm appeared after 18 months, but the symptoms of superior vena caval obstruction developed gradually, three years after pacemaker insertion. The diagnosis was confirmed by cavography and symptoms resolved with heparin therapy. Long‐term anticoagulation is indicated when thrombosis is responsible for this uncommon but important complication of transvenous pacing.

Severe watery diarrhoea in a patient with medullary thryoid carcinoma and high calcitonin levels was associated with increased distal ileal flow. Plasma from the patient inhibited small intestinal fluid absorption in dogs without affecting mucosal cyclic AMP levels. When calcitonin was removed from the plasma, the effect in experimental bowel loops was abolished but could be restored on restitution of comparable hormone levels with pure calcitonin. These studies, combined with the failure to find evidence of increased prostaglandin activity in the patient, suggest that circulating calcitonin may be a major cause of the diarrhoea in medullary thyroid carcinoma.

A new basis set is proposed for molecular self-consistent field and configuration interaction calculations. Expansion functions are proposed in the form sin (r A · p) exp (-arA 2) and cos (r A · p) exp (-ar A 2) and it is suggested that they are used as an alternative to the gaussian basis set xA iyA jzA k exp (-ar A 2). It is shown how the new basis can have the same effects, for suitable vectors p, as the gaussian basis. It is further shown that all the one and two-electron integrals in the new basis are evaluable in terms of exponentials, square roots and the complex error function erf (z). First calculations, using the new basis, are presented in LiH, HF and H2O.

The collagen concentration and the total amount of collagen per tissue were determined in the uterus, skin and femurs of intact female rats and in the skin and femurs of intact male rats which had received specific quantities of 17β-estradiol benzoate for 14 days (1.8, 3.6 and 14 μg/100 g body wt daily and 50 and 100 μg/ 100 g body wt every 2nd day) and in similar untreated male and female animals. In the estradiol benzoate-treated rats, the collagen from the 3 tissues showed contrasting changes. Although the mg of collagen/uterus of the rats treated with 1.8, 3.6 and 14 μg of estradiol benzoate/100 g body wt daily were increased significantly (p <0.01, 0.01, 0.05), the per cent collagen in the dry fat-free uterus was decreased in each group of steroid-treated animals (decrease significant at p<0.05 for 1.8 μg/100 g body wt daily and p <0.01 for other dosages). A significant decrease (p <0.05, 0.01, 0.05, 0.05) in g of collagen/total skin was observed with female rats at estradiol benzoate dosages of 1.8 and 14 μg/100 g body wt daily and 50 and 100 μg/100 g body wt every 2nd day. The g of collagen/total skin of the estradioltreated male rats was significantly decreased (p <0.01 and 0.05 at certain dosages) with 3.6 μg/ 100 g body wt and larger amounts of the steroid daily for 14 days. In the female rats the per cent collagen in the dry fat-free skin was significantly greater (p <0.01) at the 2 highest dosage levels and in the male animals the per cent collagen was increased significantly (p <0.01) in the dry fat-free skin of the animals which received estradiol injections of 1.8 μg/100 S body wt daily and 50 and 100 μg/100 g body wt every 2nd day. In the female rats, the mg of collagen/femur were increased significantly (p <0.05, 0.01, 0.05) with steroid dosages of 1.8 and 14 μg/100 g body wt daily and 100 μg/100 g body wt every 2nd day, respectively. Increases in mg of collagen/femur of male rats were significant (p <0.05) when 1.8, 3.6 and 14 μg/100 g body wt of the steroid were administered daily. The per cent collagen in the dry fat-free femurs was increased significantly (p <0.01) in the female rats which received the 3 highest quantities of estradiol benzoate and in the male rats at steroid dosages of 3.6 and 14 μg/100 g body wt daily and 100 μg/110 g body wt every 2nd day. (Endocrinology79: 486, 1966)