Presentation and treatment of spontaneous aortocaval fistula

BACKGROUND: Spontaneous rupture of abdominal aortic aneurysm into the inferior vena cava is rare. The clinical presentation is highly variable, and the diagnosis can be difficult, often being made only at operation. The aortocaval fistula results in a large left-to-right shunt, which can cause cardiac failure. Once the diagnosis is made, treatment is by surgical closure of the fistula and repair of the aneurysm with a graft. METHODS: This is a retrospective review of a single surgeon's experience with aortocaval fistula complicating abdominal aortic aneurysms. RESULTS: Over a 15-year period, we had five patients with spontaneous aortocaval fistula who were treated operatively. Preoperative diagnosis was made in two, suspected in one, and not made in two, one of whom died (the only perioperative death in the series). CONCLUSIONS: Spontaneous aortocaval fistulas are uncommon, and their preoperative recognition is difficult. Hematuria in association with an abdominal aortic aneurysm should raise the suspicion of an aortocaval fistula. Surgical correction is possible, with survival rates comparable to those associated with rupture of aneurysms into the retroperitoneum. Early operative control of the fistula is important to optimize the preload to the heart.     

Aortocaval fistula. Diagnosis using spiral x-ray computed tomography with 2D and 3D reconstructions

We report a case of arteriovenous fistula due to spontaneous rupture of an aortic aneurysm into the inferior vena cava. This is a rare complication of atheromatous aneurysm, often difficult to diagnose as the clinical presentation may be obscure. Although aortography is the reference diagnostic investigation, spiral CT acquisition with 3D and 2D reformation allowed visualization of the arteriovenous communication and provided an accurate diagnosis.     

Spontaneous aortocaval fistula secondary to ruptured abdominal aortic aneurysm

Twenty-nine patients referred consecutively to a cancer clinic because of recurrent metastatic malignant melanoma were given 5 mg of Connaught Laboratories bacillus Calmette-Guérin (BCG) by multiple cutaneous puncture at weekly and later at monthly intervals. Eight were also treated with autologous tumour vaccine and three with intralesional BCG. This group was compared with a retrospective control group of 54 patients treated with surgery and radiotherapy alone after recurrence. Prognostic features such as site of primary and of first metastasis, disease-free interval, age and sex were similar in the two groups. However, the median survival from the time of first recurrence was 12 months in the control group but 21 months in the BCG-treated group. The major improvement was in patients with disease limited to the regional lymph nodes: the median survival was 16 months in the control group but over 32 months in the BCG-treated group. Autologous tumour vaccine appeared to have no effect on survival. Serial testing of immunocompetence did not offer any prognostic advantage, although the results of some tests correleated well with extent of disease.     

Diagnosis of the abdominal vascular system by means of electron-beam computed tomography (EBT)]

Pokeweed antiviral protein (PAP) from Phytolacca americana is a highly specific N-glycosidase removing adenine residues (A4324 in 28S rRNA and A2660 in 23S rRNA) from intact ribosomes of both eukaryotes and prokaryotes. Due to the ribosome impairing activity the gene coding for mature PAP has not been expressed so far in bacteria whereas the full-length gene (coding for the mature 262 amino acids plus two signal peptides of 22 and 29 amino acids at both N- and C-termini, respectively) has been expressed in Escherichia coli. In order to determine: 1) the size of the N-terminal region of PAP which is required for toxicity to E. coli; and 2) the location of the putative enzymatic active site of PAP, 5'-terminal progressive deletion of the PAP full-length gene was carried out and the truncated forms of the gene were cloned in a vector containing a strong constitutive promoter and a consensus Shine-Dalgarno ribosome binding site. The ribosome inactivation or toxicity of the PAP is used as a phenotype characterized by the absence of E. coli colonies, while the mutation of PAP open reading frames in the small number of survived clones is used as an indicator of the toxicity to E. coli cells. Results showed that the native full-length PAP gene was highly expressed and was not toxic to E. coli cells although in vitro ribosome inactivating activity assay indicated it was active. However, all of the N-terminal truncated forms (removal of seven to 107 codons) of the PAP gene were toxic to E. coli cells and were mutated into either out of frame, early termination codon or inactive form of PAP (i.e., clone PAP delta107). Deletion of more than 123 codons restored the correct gene sequence but resulted in the loss of the antiviral and ribosome inactivating activities and by the formation of a large number of clones. These results suggest that full-length PAP (with N- and C-terminal extensions) might be an inactive form of the enzyme in vivo presumably by inclusion body formation or other unknown mechanisms and is not toxic to E. coli cells. However, it is activated by at least seven codon deletions at the N-terminus. Deletions from seven through to 107 amino acids were lethal to the cells and only mutated forms (inactive) of the gene were obtained. But deletion of more than 123 amino acids resulted in the loss of enzymatic activity and made it possible to express the correct PAP gene in E. coli. Because deletion of Tyr94 and Val95, which are involved in the binding of the target adenine base, did not abolish the activity of PAP, it is concluded that the location previously proposed for PAP enzymatic active site should be reassessed.     

Basilar artery ectasia demonstrated by computed tomography

Basilar artery eclasia was demonstrated by computed tomography (CT) in 4 cases. The course and diameter of the basilar artery as seen by CT closely approximated those aspects of the artery visualized by angiography. The clinical manifestations of basilar ectasia correlated with what brain stem structures were impinged upon by the ectatic artery.     

Differentiation of achalasia from pseudoachalasia by computed tomography

OBJECTIVES: The purpose of this study was to determine the computed tomography (CT) findings in idiopathic achalasia and in the pseudoachalasia of malignancy. METHODS: We identified 12 patients with the manometric diagnosis of achalasia who also had CT scans available for review: eight had idiopathic achalasia, and four had pseudoachalasia. As controls, we selected nine patients with endoscopically obvious esophageal cancer who also had CT scans. The CT scans were blindly reviewed to determine esophageal wall thickness, symmetry of the esophageal wall, presence of esophageal dilation or mass, and a radiological diagnosis. RESULTS: Six of the eight patients with achalasia had a dilated esophagus. Five had symmetric wall thickening >5 mm (range 7-10 mm) at the gastroesophageal junction. One patient with a 10-mm wall thickening was incorrectly diagnosed with a mass. All others were correctly diagnosed with achalasia. Three of the four patients with pseudoachalasia had esophageal dilation. Two had an obvious esophageal mass. The other two were given an indefinite diagnosis: one had asymmetric wall thickening (11 mm) at the gastroesophageal junction, and the other had symmetric thickening of 18 mm. Eight of the nine patients with obvious esophageal cancer had a mass on CT; the other patient had asymmetric wall thickening of 6 mm at the gastroesophageal junction and was given an indefinite diagnosis. CONCLUSIONS: Most achalasia patients have CT findings of esophageal dilation and mild, symmetric wall thickening. Therefore, symmetric esophageal wall thickening (<10 mm) should not dissuade one from the diagnosis of achalasia. Most pseudoachalasia patients have CT findings of esophageal dilation, more marked and/or asymmetric wall thickening, or mass. In this group, asymmetric or marked thickening (>10 mm) indicated pseudoachalasia. Therefore, CT can be helpful in differentiating between achalasia and the pseudoachalasia of malignancy.     

Liver volume in children measured by computed tomography

Primary malignant melanoma of the urethra is very rare. In the male, the distal urethra is the most common site. The histopathology does not usually differ from that of melanoma at other body sites. This report describes a case of urethral malignant melanoma which closely resembled urethral carcinoma. It showed both papillary and solid growth, and the diagnosis only became apparent from special stains. Pathologists should be aware of this rare occurrence.     

Quantitative X-ray computed tomography

Quantitative X-ray Computed Tomography (QCT) has an advantage to be able to determine three-dimensional bone density of lumbar vertebral body compared with dual energy X-ray absorptiometry (DXA) method. We introduced the high reproductable QCT method as a simplified manual operation avoiding simultaneous imaging of both patients and bone mass phantoms. The coefficient of variation of values measured by phantom study was 0.6% for 7 years in our hospital. In measuring of 144 healthy Japanese women, the bone mineral density of lumbar spine was most likely to be decreased linealy with age.     

The role of xenon-enhanced computed tomography in the management of a traumatic carotid-cavernous fistula: case report

Ammonia liberated during amino acid catabolism in mammals is highly neurotoxic and is detoxified by the five enzymes of the urea cycle that are expressed within the liver. Inborn errors of each of the urea cycle enzymes occur in humans. Carbamoyl phosphate synthetase I (CPSase I; EC 6.3.4.16) is located within the inner mitochondrial matrix and catalyzes the initial rate-limiting step of the urea cycle. Unless treated, complete deficiency of CPSase I, a rare autosomal recessive disease, causes death in newborn infants. Survivors are often mentally retarded and suffer frequent hyperammonemic crises during intercurrent illness or other catabolic stresses. Biochemically, CPSase I deficiency is characterized by high levels of blood ammonia, glutamine, and alanine, with low or absent citrulline and arginine levels. As a first step toward the development of gene therapy directed to the hepatocyte, we have generated a CPSase I-deficient mouse by gene targeting. Mice with homozygous disruption of CPSase I (CPSase [-/-] mice) die within 36 hours of birth with overwhelming hyperammonemia, and without significant liver pathology. This animal is a good model of human CPSase I deficiency.     

Successful treatment of a persistent cutaneous fistula to the seminal tract: imaging with three-dimensional computed tomography

The best position for Centers for Disease Control (Atlanta, GA) light traps, in relation to human-occupied bed nets for trapping of host-seeking Anopheles gambiae Giles and Culex quinquefasciatus Say mosquitoes, was determined in Tanzania. Significantly higher catches were recorded for both species when the trap was positioned at the foot end of the bed, near the top of the net. Parity rates were significantly higher near the top of the net than at the level of the host. Since trap position affects the catch size and the proportion of infectious mosquitoes therein, standardized use of this sampling technique for estimating entomologic inoculation rates (i.e., the number of potentially infectious bites received over a certain period of time) is recommended.     

Hyoid bone malformation confirmed by 3-dimensional computed tomography

We describe the case of a young woman with pain on turning her head attributable to a malformation of the hyoid bone. Diagnosis was established using spiral computed tomography with the patient's neck in the position of greatest discomfort and with 3-dimensional reconstruction of the hyoid bone. Prior conventional radiography and magnetic resonance imaging did not aid in finding a diagnosis. After surgical removal of both greater cornua of the hyoid bone there was a complete relief of symptoms.     

Spontaneous pneumomediastinum: origin identified by chest computed tomography

Spontaneous pneumomediastinum (SPM) is an uncommon disorder. The mechanism of spontaneous pneumomediastinum has been speculated as follows: when air pressure in the alveoli rapidly increases, free air leaks from ruptured alveoli and accumulates along the bronchovascular tissue sheath, and then free air moves toward the mediastinum. In this case report of a 19-year-old man of SPM, a chest computed tomography (CT) revealed air in a tubular shape along the pulmonary artery in the apico-posterior segment of the left lung field. This is the first case in which the process of SPM could be identified by chest CT.     

New dimensions in computed tomography

Total body CT scanning may be utilized as a means of treatment planning for radiation therapy. Computer reconstruction of coronal and sagittal views from CT cross-sectional slices was accomplished by taking each of the cross-sectional images and placing them together in the specific order in the sequence in which they were scanned to form a cube. Once the cube is built, retrieving in the sagittal and coronal views is readily achieved.     

Arachnoid cysts on computed tomography

The appearances of arachnoid cysts on computed tomography are presented. They are well defined lesions with the same density as cerebrospimal fluid and are not contrast enhanced. Superficial lesions are biconvex or semicircular and may have a characteristic straight inner margin. Deep lesions and cysts between the cerebellar hemispheres are spherical and some may be difficult to differentiate from cystic neoplasms. The etiology and clinical manifestations of arachnoid cysts are also briefly discussed.     

High-helical-pitch, cone-beam computed tomography

Bovine spleen NAD+glycohydrolase, an ecto-enzyme closely related to CD38, catalyzes the conversion of NAD+ into ADP-ribose and cyclic ADP-ribose, a calcium-mobilizing metabolite. We have raised polyclonal antibodies against the native enzyme which on immunoblots revealed, besides the 32 kDa monomer, the presence of a stable dimeric form. This dimerization was shown to result from a spontaneous oxidative process involving the formation of one or several disulfide bond(s) sensitive to reducing agents such as 2-mercaptoethanol. The homodimeric oxidized enzyme, which was not detected during the early steps of the enzyme purification procedure, was catalytically active. Our results underline the differences, in terms of oligomerization and reactivity towards thiols, between CD38/NAD+glycohydrolases depending on their origin.