Myopericarditis: recognition and impact in the military population.

We present a case of a fit and well British Army officer with sudden-onset chest pain following a viral illness, on a background of arduous skiing over an 8-week period. This resulted in a 6-month downgrade with no clearly defined plan for return to full fitness and deployability. The diagnosis and differentiation of myopericarditis from other causes of chest pain is reviewed. The treatment and management of myopericarditis is summarised and commentary is made on the paucity of evidence underpinning the return to fitness guidelines. The impact of this condition primarily affecting young fit individuals, commonly exacerbated by viral illness and arduous activity, is discussed in the context of individual employability and operational capability in a military setting.

The role of embolization in reducing the complications of cryoablation in renal cell carcinoma.

AIM: To investigate whether embolization prior to cryoablation would decrease morbidity without negative effects on tissue pathology, renal function, or recurrence. MATERIAL AND METHODS: The electronic medical records of all patients undergoing cryoablation for renal cell carcinomas were reviewed for lesion size, pre-ablative renal function, post-ablative renal function, post-ablative complications, recurrence, and quality of biopsy specimen. Comparisons were made between patients who underwent cryoablation (the Cryo-Only group) and those who underwent cryoablation after same-day coil embolization of their lesion (the Cryo-Embo group). Further comparison was made between the Cryo-Embo lesions and the subset of larger Cryo-Only lesions (≥ 3 cm), which were expected to have a higher natural complication rate. RESULTS: A total of 21 lesions in 19 patients were treated by percutaneous cryoablation (17 Cryo-Only, four Cryo-Embo). Complications were seen in 83% of the large Cryo-Only lesions (average size 3.6 cm), whereas no complication was seen amongst Cryo-Embo lesions (average size 4 cm). Embolization significantly decreased complications between size-matched lesions (p = 0.048) without impacting renal function (p = 1), biopsy quality (p = 1), or recurrence (p = 1). CONCLUSION: Performance of trans-arterial embolization prior to cryoablation of large renal cell carcinomas significantly decreases complications, such as haemorrhage, without a discernible effect on biopsy quality, renal function, or recurrence rate.

Neurophysiological identification of the subthalamic nucleus in surgery for Parkinson's disease.

Microelectrode recording methods for stereotactic localization of the subthalamic nucleus (STN) and surrounding structures are described. These methods accurately define targets for chronic deep brain stimulation in the treatment of Parkinson's disease. Mean firing rates and a burst index were determined for all recorded neurons, and responses to active and passive limb and orofacial movements were tested. STN neurons had a mean firing rate of 37+/-17 Hz (n = 248) and an irregular firing pattern (median burst index, 3.3). Movement-related activity and tremor cells were identified in the STN. Ventral to the STN, substantia nigra pars reticulata neurons had a mean rate of 71+/-23 Hz (n = 56) and a more regular firing pattern (median burst index, 1.7). Short trains (1-2 seconds) of electrical microstimulation of STN could produce tremor arrest but were not found to be useful for localization. Compared with data from normal monkeys our findings suggest that STN neuronal activity is elevated in Parkinson's disease.

Detection of main renal artery stenosis using phase-contrast cine MR angiography.

OBJECTIVE: The purpose of our study was to assess the ability of phase-contrast cine MR angiography to detect the presence of main renal artery stenosis. SUBJECTS AND METHODS: We prospectively evaluated 75 hypertensive patients form main renal artery stenosis using phase-contrast cine MR angiography. Each main renal artery was evaluated as normal or abnormal. Thirty-seven of the 75 patients underwent conventional arteriography or intraarterial digital subtraction arteriography; these results were compared with the MR angiographic interpretations. Only those patients who had confirmatory arteriography were included in the statistical analysis. RESULTS: Thirty-six main renal arteries interpreted as normal by MR angiography were found to be without a focal stenosis on invasive arteriography. MR angiography suggested 32 main renal artery stenoses; invasive arteriography showed 29 of these as stenoses. Three main renal arteries that were interpreted as having focal stenoses by MR angiography were shown to be not stenotic by invasive arteriography. Three other patients had diffusely narrowed main renal arteries bilaterally without a focal stenosis on MR angiography; bilateral proximal renal artery stenoses were seen at arteriography in two of these patients, and diffusely narrowed main renal arteries were seen in the third patient. Thus, the sensitivity of phase-contrast cine MR angiography for detecting a focal stenosis or abnormal main renal artery was 100% (95% confidence interval, 88-100%) and the specificity was 93% (95% confidence interval, 80-99%). The kappa coefficient was 0.85 with a standard error of 0.08. CONCLUSION: Phase-contrast cine MR angiography had a high degree of accuracy and a high negative predictive value in detecting the presence of main renal artery stenoses and may be a good screening technique for renovascular hypertension.

Strain variation in tumor necrosis factor induction by parasites from children with acute falciparum malaria.

A small proportion of individuals infected with Plasmodium falciparum develop cerebral malaria. Why it affects some infected individuals but not others is poorly understood. Since tumor necrosis factor (TNF) has been implicated strongly in the pathogenesis of cerebral malaria, here we have compared different parasite isolates for their ability to induce TNF production by human mononuclear cells in vitro. Wild isolates were collected from 34 Gambian children with cerebral malaria and 66 children with uncomplicated malaria fever. Cerebral malaria isolates tended to stimulate more TNF production than mild malaria isolates, but there was considerable overlap between the two groups, and the present data provide only limited support for the hypothesis that cerebral malaria is caused by strains of P. falciparum inducing high levels of TNF. However, it is notable that the amounts of TNF induced by different wild isolates from a single locality differed by over 100-fold. The biological significance of this polymorphism deserves further scrutiny in view of the central role that TNF is believed to play in host defense and in the clinical symptomatology of human malaria.

Emphysematous gastritis in an immunocompromised host.

Emphysematous gastritis is a rare, often lethal condition of gastric mural inflammation and gaseous dissection. Infection with gas-forming organisms is the most frequently cited cause. In all previously reported patients, the clinical presentation was dramatic. We report on an immunocompromised host who had a surprisingly subtle clinical presentation.

Strut interlocking of titanium Greenfield vena cava filters and its effect on clot capturing: an in vitro study.

PURPOSE: To determine the influence of filter leg-interlocking on filtering efficiency of titanium Greenfield inferior vena cava filters in an in vitro model. METHODS: Titanium Greenfield filters (TGF) were placed in an inferior vena cava (IVC) flow phantom with no interlocking legs, or with one or two pairs of legs interlocked. Clot emboli of varying sizes were introduced into the stream of flow, and the frequency of successful captures by the deformed filters was recorded. RESULTS: Interlocking filter legs diminished the filtering efficiency of the TGF by up to 80% with the flow phantom in a horizontal position; no such compromise existed when the phantom was in a vertical position. CONCLUSION: When leg interlocking is verified radiographically, the filtering efficiency of the TGF is reduced, and placement of a second IVC filter may be indicated.

Percutaneous retrieval of a misplaced titanium Greenfield filter.

Vena caval filters are considered permanent indwelling devices. Occasionally, malposition of a filter prompts a desire for its removal. We report a method of percutaneous retrieval of a titanium Greenfield filter by snare.

Plasmodium falciparum varies in its ability to induce tumor necrosis factor.

Tumor necrosis factor (TNF) has a variety of protective and pathological actions in human malaria. We report that different laboratory lines of Plasmodium falciparum which were derived from a single wild isolate (IT 4/25/5) varied widely in their ability to stimulate TNF production by human mononuclear cells. In the cloned line R29 we observed that subcultures selected for high rosetting frequency gave significantly higher levels of TNF stimulation than subcultures with low rosetting frequency, indicating that TNF induction can vary within populations that have originated from a single genotype. These results raise the possibility that the clinical severity of malaria is partly determined by the TNF-inducing activity of the infecting strain of parasite.

Portal venous branch targeting with a platinum-tipped wire to facilitate transjugular intrahepatic portosystemic shunt (TIPS) procedures.

We describe a technique to aid in technically difficult transjugular intrahepatic portosystemic shunt (TIPS) procedures by sonographically guided transabdominal fine-needle portal vein puncture for placement of a 0.018-inch platinum-tipped target guidewire within an appropriate portal venous branch.

Uncomplicated amebic liver abscess: prospective evaluation of percutaneous therapeutic aspiration.

The performance of therapeutic aspiration in the treatment of amebic liver abscess, advocated and practiced in many centers, is controversial. Previously, this practice has been evaluated in retrospective analyses. To test the potential benefit of therapeutic aspiration, the authors undertook a prospective randomized trial in 57 patients admitted for suspected amebic liver abscess during a 15-month period. Sixteen patients were excluded from the trial. The remaining 41 patients were randomly included in one of two study groups to receive amebicidal therapy alone or amebicidal therapy coupled with image-guided percutaneous therapeutic aspiration. All patients in the trial recovered. No statistically significant benefit was demonstrated in the aspiration group for the two objective parameters evaluated: length of hospitalization and duration of time to becoming afebrile. Subjective improvement in symptoms after aspiration was greater in the aspiration group at a marginally statistically significant level. These data do not support the adjunctive performance of percutaneous therapeutic aspiration in the treatment of uncomplicated amebic liver abscess. Amebicidals alone were equally efficacious in treating the group studied.

Cyst and host tissue concentrations of mebendazole in patients undergoing surgery for hydatid disease.

Mebendazole levels were assayed by high performance liquid chromatographic assay in plasma, host tissues, and hydatid material taken from four patients who underwent surgery for hydatid disease. The drug was absorbed and had penetrated both into the host and into the parasite material. The levels of the drug in viable hydatid cysts were much lower than those in dead cysts. The possibility of exclusion or detoxification of the drug by viable hydatid cysts is raised.

The metabolic and pharmacokinetic disposition of mebendazole in the rat.

The metabolism and pharmacokinetics of mebendazole was studied in rats using [2'-3H]-mebendazole (biologically stable; specific activity 383.9 (mCi/mMol) and [2-14C]-mebendazole (specific activity 2.57 mCi/mMol). Analyses were performed by high pressure liquid chromatography and liquid scintillation spectrometry. About 85% of an intravenous dose was eliminated with the bile and the remainder with the urine. The majority of the dose was recovered as conjugated metabolites. The major metabolite (methyl-5(6)-(alpha-hydroxybenzyl)-2-benzimidazole carbamate) accounted for about 77% of the total recovered and 99% of it was conjugated. Anaerobic metabolism studies conducted in vitro with intestinal microorganisms obtained from rats indicated that metabolism of mebendazole did not occur in the gut, but that the intestinal microflora was able to hydrolyse conjugated metabolites which were eliminated with the bile. Mebendazole was found to have a biphasic elimination profile after intravenous administration. Its terminal plasma elimination half-life was 3.2 hours and its re-distribution half-life was 0.4 hour. After oral administration, as a solution in aqueous dimethyl sulphoxide, a bioavailability of 53% was obtained.

Preliminary observations on the biliary elimination of mebendazole and its metabolites in patients with echinococcosis.

The biliary excretion of mebendazole has been investigated in two patients to whom it was given for the treatment of echinococcosis, although it was found to be only partly effective. Oral mebendazole was extensively metabolized and the conjugated parent substance and its metabolites were excreted in the bile. One patient without cholestasis and with normal liver function had an apparent total biliary clearance (776 ml/min) which approached the hepatic plasma flow. The other patient with cholestasis and impairment of the hepatic drug metabolizing capacity showed a drastically reduced apparent total biliary clearance of 3.8 ml/min. The average plasma level of mebendazole was significantly lower in the former and higher in the latter patient (0.06 and 0.91 nmol/ml, respectively). The data suggest that impaired metabolism and/or biliary elimination can account for the higher plasma mebendazole level in patients with liver damage.

The pharmacokinetics and bioavailability of mebendazole in man: a pilot study using [3H]-mebendazole.

Following the intravenous administration of a tracer dose (1.7 microgram) of [3H]-mebendazole to a man, an elimination half-life of 1.16 h was observed and the volume of distribution was calculated to be 2.03 l/kg. After oral administration of the same dose, an elimination half-life of 0.74 h was observed. The bioavailability of mebendazole from the solution was found to be 17%.

Clinical pharmacokinetics of high dose mebendazole in patients treated for cystic hydatid disease.

The plasma concentrations of mebendazole and its metabolites have been monitored in twelve patients after receiving a 10 mg/kg dose for cystic hydatid disease. The mebendazole plasma concentration-time profiles differed considerably between patients; elimination half-lives ranged from 2.8-9.0 h, time to peak plasma concentration after dosing ranged from 1.5-7.25 h and peak plasma concentrations ranged from 17.5 to 500 ng/ml. The mean peak plasma concentration of mebendazole after an initial dose (69.5 ng/ml) was lower than found in patients during chronic therapy (137.4 ng/ml). The plasma AUCTS for the major metabolites of mebendazole (methyl 5-(alpha-hydroxybenzyl)-2-benzimidazole carbamate and 2-amino-5 benzoylbenzimidazole) were about five times the plasma AUCT found for mebendazole in patients on chronic therapy. It is suggested that the slower clearance of these polar metabolites relative to mebendazole results from enterohepatic recycling. Since mebendazole is also highly plasma protein bound, caution should be observed in administering mebendazole to patients with liver disease. Concentrations of mebendazole found in the tissue and cyst material collected from two patients during surgery ranged from 59.5 to 206.6 ng/g wet weight.

Identification of biliary metabolites of mebendazole in the rat.

Three metabolites of mebendazole were isolated from the bile of rats dosed with a mixture of mebendazole and pentadeuteromebendazole. The identification was based upon the appearance of the characteristic doublet in the mass spectrum of the compounds and the comparison of their fragmentations with those of authentic compounds. Cochromatography of the metabolites with the authentic compounds on HPLC supported the identification. Methyl-5(6)-(alpha-hydroxybenzyl)-2-benzimidazole carbamate, 2-amino-5(6)-(alpha-hydroxybenzyl) benzimidazole and 2-amino-5(6)-benzoylbenzimidazole were identified as metabolites after enzymic conjugate hydrolysis. Some unmetabolized mebendazole was also found.

Two high-performance liquid chromatographic determinations for mebendazole and its metabolites in human plasma using a rapid Sep Pak C18 extraction.

A rapid extraction procedure for mebendazole and its metabolites from plasma using Sep Pak C18 is described. This method eliminates the need for solvent extractions as such. Two reversed-phase high-performance liquid chromatographic determinations for these extracts, one isocratic elution and the other gradient elution, using an analytical wavelength of 254 nm are also presented. The gradient elution system provides superior resolution of these compounds and consequently has improved determination limits. For mebendazole the determination limits are 20 ng/ml (isocratic system) and 10 ng/ml (gradient system).

The effect of dioctyl sodium sulphosuccinate on tartrazine azo reduction by intestinal bacteria.

1. Washed whole-cell suspensions of Proteus vulgaris and micro-organisms from rat faeces, reductively cleave the azo bond of the food dye tartrazine under anaerobic conditions. 2. Dioctyl sodium sulphosuccinate, a common faecal softening laxative, when added to incubations in vitro at concentrations greater than 0.005%, increases tartrazine azo reduction in P. vulgaris whole-cell suspensions. 3. By contrast, concentrations of dioctyl sodium sulphosuccinate greater than 0.005% when added to incubations in vitro of rat faecal preparations, resulted in an inhibition of tartrazine azo reduction.