Identification of the biosynthetic gene cluster for 3-methylarginine, a toxin produced by Pseudomonas syringae pv. syringae 22d/93

The epiphyte Pseudomonas syringae pv. syringae 22d/93 (Pss22d) produces the rare amino acid 3-methylarginine (MeArg), which is highly active against the closely related soybean pathogen Pseudomonas syringae pv. glycinea. Since these pathogens compete for the same habitat, Pss22d is a promising candidate for biocontrol of P. syringae pv. glycinea. The MeArg biosynthesis gene cluster codes for the S-adenosylmethionine (SAM)-dependent methyltransferase MrsA, the putative aminotransferase MrsB, and the amino acid exporter MrsC. Transfer of the whole gene cluster into Escherichia coli resulted in heterologous production of MeArg. The methyltransferase MrsA was overexpressed in E. coli as a His-tagged protein and functionally characterized (K(m), 7 mM; k(cat), 85 min(-1)). The highly selective methyltransferase MrsA transfers the methyl group from SAM into 5-guanidino-2-oxo-pentanoic acid to yield 5-guanidino-3-methyl-2-oxo-pentanoic acid, which then only needs to be transaminated to result in the antibiotic MeArg.

Sympatho-adrenal secretion in humans: factors governing catecholamine and storage vesicle peptide co-release

1. In postganglionic sympathetic neurones and adrenal chromaffin cells, catecholamines are co-stored in vesicles with soluble peptides, including chromogranin A (CgA) and neuropeptide Y (NPY), which are subject to exocytotic co-release with catecholamines. 2. Plasma catecholamine, CgA and NPY responses to stimulators and inhibitors of sympatho-adrenal catecholamine storage and release were measured in humans. Short-term, high-intensity dynamic exercise, prolonged low-intensity dynamic exercise, and assumption of the upright posture, in decreasing order of potency, predominantly stimulated noradrenaline (NA) release from sympathetic nerve endings. Only high-intensity exercise elevated CgA and NPY, which did not peak until 2 min after exercise cessation. Stimulated NA correlated with plasma CgA 2 min after exercise, and with NPY 5 min after exercise. 3. Insulin-evoked hypoglycaemia and caffeine ingestion, in decreasing order of potency, predominantly stimulated adrenaline (AD) release from the adrenal medulla. During insulin hypoglycaemia AD and CgA rose, but NPY was unchanged. Neither NPY nor CgA were altered by caffeine. The rise in CgA after intense adrenal medullary stimulation was greater than its rise after intense sympathetic neuronal stimulation (1.4-versus 1.2-fold, respectively). 4. Infusion of tyramine, which disrupts sympathetic neuronal vesicular NA storage, elevated systolic blood pressure and NA, while NPY and CgA were unchanged. After reserpine, another disruptor of neuronal NA storage, NA transiently rose and then fell; NPY and CgA were unaltered. After the non-exocytotic adrenal medullary secretory stimulus glucagon. AD rose while NA, CgA and NPY did not change. After amantadine, an inhibitor of protein endocytosis, both CgA and fibrinogen rose, while NA and NPY remained unaltered. Neither CgA, NPY, nor catecholamines were altered by the catecholamine uptake and catabolism inhibitors desipramine, cortisol, and pargyline. 5. Human sympathetic nerve contained a far higher ratio of NPY to catecholamines than human adrenal medulla, while adrenal medulla contained far more CgA than sympathetic nerve. 6. It is concluded that peptides are differentially co-stored with catecholamines, with greater abundance of CgA in the adrenal medulla and NPY in sympathetic nerve. Activation of catecholamine release from either the adrenal medulla or sympathetic nerves, therefore, results in quite different changes in plasma concentrations of the catecholamine storage vesicle peptides CgA and NPY. Only profound, intense stimulation of chromaffin cells or sympathetic axons measurably perturbs plasma CgA or NPY concentration; lesser degrees of stimulation perturb plasma catecholamines only. Neither CgA nor NPY are released during non-exocytotic catecholamine secretion.

Percutaneous transluminal angioplasty of proximal subclavian artery stenosis after left internal mammary to left anterior descending artery bypass surgery

A patient is described who underwent percutaneous transluminal angioplasty, through a brachial approach, of a high grade stenosis at the proximal portion of the left subclavian artery 1.5 years after coronary artery bypass grafting including left internal mammary to left anterior descending artery anastomosis. Symptoms of class IV angina, vertebrobasilar insufficiency and occupational arm claudication that developed after bypass surgery were promptly relieved after balloon dilation. Percutaneous transluminal angioplasty of the subclavian artery can be performed safely and provides an alternative to carotid-subclavian or axillary-axillary bypass surgery for treatment of internal mammary artery graft malfunction.

Bismuth subsalicylate in the treatment of acute diarrhea in children: a clinical study

Bismuth subsalicylate (BSS) and placebo were evaluated in a double-blind, placebo-controlled study as adjunct to rehydration therapy in 123 children, aged 4 to 28 months, hospitalized with acute diarrhea. The dosing regimen was 20 mg/kg five times daily for 5 days. Significant benefits were noted in the BSS group compared with placebo as manifested by decreases in stool frequency and stool weights and an improvement in stool consistency, significant improvement in clinical well-being, and shortening of the disease duration. Patients treated with BSS had a significant reduction in duration of hospital stay (6.9 days) compared with placebo-treated patients (8.5 days). Also, intravenous fluid requirements decreased significantly more rapidly and to a greater degree in the BSS-treated group. Bismuth subsalicylate was associated with clearance of pathogenic Escherichia coli from the stools in 100% of cases but was not different from placebo in rotavirus elimination. Bismuth subsalicylate was well tolerated with no reported adverse effects. Blood bismuth and serum salicylate levels were well below levels considered toxic. In this study, BSS provided effective adjunctive therapy for acute diarrhea, allowing children to get well sooner with less demand on the nursing and hospital staff.

Urinary tract injury in patients with blunt chest trauma: the value of postaortographic abdominal radiographs

Patients who require thoracic aortography for blunt decelerating chest trauma often sustain injury to other organ systems due to the magnitude and mechanism of injury. Hospital records and radiographs of 117 consecutive, injured patients studied with thoracic aortography were evaluated to assess the accuracy, value, and limitations of postaortographic abdominal plain radiography for detection of major genitourinary injury. In summary, major urinary tract injury occurred with a frequency of 6%, enough to justify a rapid, low cost, noninvasive screening procedure. Postaortographic plain films of the abdomen were found to be an accurate (95%) screen for detection of major urinary tract injury. The sensitivity for detection of patients with renal injury was 100%. The ability to correctly predict patients who may be safely observed (no significant renal injury) was 100%. One limitation of this technique was the poor diagnostic quality found in 15% of the abdominal radiographs, most commonly caused by excessive superimposed bowel gas. Postaortographic pelvic radiographs were believed to be valuable for detection, but not exclusion, of bladder rupture.

Intravenous digital subtraction renal angiography: use in screening for renovascular hypertension

Intravenous digital subtraction renal angiography (DSRA) has been compared with conventional angiography only in small, selected series of hypertensive patients. The authors prospectively examined with intravenous DSRA 94 patients at increased risk for renovascular hypertension and compared these studies with conventional angiography. A stenosis of at least one main renal artery was identified with intravenous DSRA in 22 patients and confirmed in 20 patients. No significant stenoses were seen with conventional angiography in any of the 64 patients in whom lesions were not seen with intravenous DSRA. Since inadequate DSRA studies were considered positive for renal artery stenosis, the sensitivity of intravenous DSRA was 100% (25 of 25); specificity, 93% (64 of 69); positive predictive value, 83% (25 of 30); and negative predictive value, 100% (64 of 64). The authors conclude that intravenous DSRA is a sensitive test for identifying stenosis of the main renal arteries and is appropriate to use as a screening test among patients at increased risk for renovascular hypertension.

Pulmonary embolism

Pulmonary embolism is a common medical problem whose incidence is likely to increase in our aging population. Although it is life-threatening, effective therapy exists. The treatment is not, however, without significant complications. Thus, accurate diagnosis is important. Unfortunately, the clinical manifestations of pulmonary embolism are nonspecific. Furthermore, in many patients the symptoms of an acute embolism are superimposed on underlying chronic heart or lung disease. Thus, a high index of suspicion is needed to identify pulmonary emboli. Laboratory parameters, including arterial oxygen tensions and electrocardiography, are as nonspecific as the clinical signs. They may be more useful in excluding another process than in diagnosing pulmonary embolism. The first radiologic examination is the chest radiograph, but the clinical symptoms are frequently out of proportion to the findings on the chest films. Classic manifestations of pulmonary embolism on the chest radiograph include a wedge-shaped peripheral opacity and a segmental or lobar diminution in vascularity with prominent central arteries. However, these findings are not commonly seen and, even when present, are not specific. Even less specific findings include cardiomegaly, pulmonary infiltrate, elevation of a hemidiaphragm, and pleural effusion. Many patients with pulmonary embolism may have a normal chest radiograph. The chest radiograph is essential, however, for two purposes. First, it may identify another cause of the patient's symptoms, such as a rib fracture, dissecting aortic aneurysm, or pneumothorax. Second, a chest radiograph is essential to interpretation of the radionuclide V/Q scan. The perfusion scan accurately reflects the perfusion of the lung. However, a perfusion defect may result from a variety of etiologies. Any process such as vascular stenosis or compression by tumor may restrict blood flow. In addition, areas of the lung that are not well ventilated will be poorly perfused. Thus, a ventilation scan and a chest radiograph are essential to optimal interpretation of the perfusion scan. Ventilation/perfusion scans are interpreted as degrees of probability of pulmonary embolism. Emboli are not present in patients with a normal V/Q scan. An embolus is unlikely (10%-15%) among patients with a low-probability V/Q scan. However, small emboli that are nonocclusive may be present, and pulmonary arteriography may be used to further evaluate patients with a high clinical suspicion of pulmonary embolus.(ABSTRACT TRUNCATED AT 400 WORDS)

Fibromuscular dysplasia of renal arteries: comparison of intravenous digital subtraction angiography with conventional angiography

Intravenous digital subtraction angiography (IV-DSA) was compared with conventional arteriography (CA) in 14 patients with fibromuscular dysplasia (FMD) of at least one renal artery. IV-DSA identified 29 of the 34 renal arteries detected by CA. A diagnostic quality IV-DSA examination was obtained in 23 of 29 renal arteries (78%). In adequately imaged renal arteries, IV-DSA correctly identified 12 of 20 FMD renal arteries, misdiagnosed 8 FMD renal arteries as normal and correctly identified 3 normal renal arteries. These poor results, due to poor spatial resolution and subtraction artifacts inherent in the IV-DSA system, warrant careful interpretation of negative examinations and further evaluation of high risk patients.

Comparison of intravenous digital subtraction angiography and conventional arteriography in defining renal anatomy

Intravenous digital subtraction renal angiography (IV-DSRA) is frequently used in the preoperative evaluation of living-related (LR) kidney donors. However, the true accuracy of IV-DSRA in the donor population is difficult to assess since abnormalities of the kidney and its circulation are uncommon in this group. Therefore, we evaluated IV-DSRA in a group of patients more likely to have anomalies and abnormalities that would affect LR donor selection, donor nephrectomy, and subsequent transplantation. Hypertensive adults being evaluated for renovascular hypertension had IV-DSRA and conventional renal arteriograms, which were interpreted independently. We determined the accuracy of IV-DSRA, compared with conventional arteriography, in detecting multiple renal arteries, renal artery stenosis, fibromuscular dysplasia, and abnormal renal parenchyma. Technically unsatisfactory studies were excluded from analysis. Of 59 patients evaluated, 37 had abnormalities or anomalies. IV-DSRA failed to detect 28 of 50 findings in these 37 patients. In 21 patients with multiple renal arteries, IV-DSRA underestimated the number of main renal arteries in 8. Significant renal artery stenosis, present in 16 patients, was undetected by IV-DSRA in 3 of these patients. Mild fibromuscular dysplasia was not detected by IV-DSRA in any of the 5 patients with this condition, and abnormalities of renal parenchyma were not detected in 6 of the 8 patients with scarred or cystic kidneys. When compared with conventional renal arteriography in a hypertensive population, the IV-DSRA does not accurately detect abnormalities of the kidney and its circulation. If these data are confirmed in nonhypertensive subjects, preoperative evaluation of LR kidney donors using IV-DSRA alone may fail to detect potentially important anatomic abnormalities.

Pulmonary angiography with iopamidol: patient comfort, image quality, and hemodynamics

The choice of a contrast agent for pulmonary angiography has important implications for patient comfort, image quality, and perhaps the safety of the procedure, particularly for "high-risk" patients. In a prospective study the nonionic, low-osmolality agent iopamidol eliminated the problem of image degradation due to coughing, and patients showed excellent tolerance for it. However, pressure measurements obtained within 3-5 minutes of injection of iopamidol and diatrizoate sodium meglumine 76% showed no significant difference in the hemodynamic effects of the two contrast agents, either for normotensive or for pulmonary hypertensive patients. Contrary to a common presumption, pulmonary hypertension by itself did not appear to increase the risk of pulmonary angiography. The theoretic presumption of greater hemodynamic stability with low-osmolality contrast agents was not clinically evident in this trial with iopamidol. At present, enhanced patient comfort and improved image quality remain the only confirmed bases for choosing this contrast agent for pulmonary angiography.

Contrast venography of the leg: diagnostic efficacy, tolerance, and complication rates with ionic and nonionic contrast media

A prospective, three-center study of two contrast agents for leg venography was performed to evaluate both the relative frequency of adverse effects and whether low-osmolality agents provided significant advantages for this procedure. Fifty-four patients were studied with the standard preparation (iothalamate meglumine) and 57 with a nonionic agent (iopamidol). Both were used at an iodine concentration of 200 mg/mL, and there were no differences in volume of contrast material, duration of infusion, percentage of positive studies, or overall diagnostic adequacy. Patient discomfort was less with iopamidol than with iothalamate (18% vs. 44%), although discomfort was generally mild in both groups. By objective follow-up studies, the frequency of postvenographic thrombosis was not significantly different in the two groups (8% vs. 9%). Contrast venography, then, had a low frequency of complications when either a dilute conventional or a low-osmolality agent was employed. Although the frequency of postvenographic thrombosis was low with both agents, patient discomfort was less with the low-osmolality formulation.

Stenoses in dialysis fistulas: treatment with percutaneous angioplasty

Percutaneous transluminal angioplasty (PTA) was performed on 30 stenotic lesions in 25 dialysis access fistulas. The fistulas were in 23 patients with a mean age of 53 years. Lesions were detected with angiography within a few days after poor flow or increased venous pressure was documented during dialysis. Twenty-two lesions were in patients with polytetrafluoroethylene graft fistulas, five were in patients with bovine carotid fistulas, and three were in patients with endogenous arteriovenous fistulas. There were 28 venous stenoses (20 at the anastomotic site and eight more proximally) and two arterial stenoses. The overall success rate was 80%, with a 6-month patency of 76% and a mean patency after PTA of 9.4 months. Among the venous lesions, the success was 100% for proximal lesions and 71% for anastomotic lesions. There were two technical failures, which required surgery for revision of the fistulas, and four self-limited hematomas. PTA is a safe and effective treatment for stenoses in dialysis fistulas, particularly for lesions remote from the anastomotic sites.

Percutaneous intervention in the solitary kidney

The solitary kidney, either after nephrectomy or on a congenital basis, may be impaired by infection, stones, obstruction, and trauma. Because of the possibility of further renal compromise by damage of the remaining nephron units, there is reluctance to utilize percutaneous techniques in cases of solitary kidney, and surgery is often used as an alternative. We report 15 cases of solitary kidney in which interventional radiologic techniques (i.e., percutaneous nephrostomy, ureteral stenting, ureteral dilatation, and stone extraction) were attempted for the preservation of renal function, either as a permanent solution or as a temporizing maneuver prior to definitive therapy. In each case, these goals were achieved and there were no complications.

Intravenous digital subtraction angiography in the evaluation of potential renal donors

Of 65 surgically removed donor kidneys intravenous digital subtraction angiography demonstrated accurately the number of renal arteries in 58 (89 per cent). All accessory vessels missed at digital subtraction angiography were small and their presence did not interfere with successful transplantation in those donated. Of 50 surgically removed donor kidneys examined with conventional aortography only before the routine use of intravenous digital subtraction angiography the number of renal arteries was demonstrated accurately in 46 (92 per cent). Intravenous digital subtraction angiography offers advantages over conventional aortography, including most importantly the routine performance on an outpatient basis, and decreased film cost and examination time. Although the accuracy of conventional aortography (92 per cent) in detecting the number of renal arteries is slightly greater than that for intravenous digital subtraction angiography (89 per cent), the advantages of the digital examination justify its use as the initial examination for the potential renal donor. Conventional aortography can be reserved for use in patients with equivocal or technically inadequate digital examinations.

Digital intravenous subtraction angiography in the evaluation of reconstructed renal arteries

Digital intravenous subtraction angiography (DISA) was used to evaluate 28 patients who had undergone renal artery reconstruction either as part of a renal transplant procedure or for treatment of renovascular hypertension. Satisfactory visualization of the renal artery was obtained in 26 cases, and the clinical questions were adequately answered in these cases. The findings included a variety of possible outcomes and demonstrate the adequacy of DISA as a means of evaluating the results of renal artery surgery. Technical and anatomic factors affecting the quality of the examination are discussed. The cases also illustrate the critical importance of thorough familiarity with the surgical procedures in general and of mutual discussion between surgeon and radiologist in optimizing the DISA examination in a given patient.

Transthoracic needle aspiration: use of a small chest tube to treat pneumothorax

The primary complication of transthoracic needle aspiration is pneumothorax. The efficacy and safety of using a small chest tube to treat this complication were examined by reviewing the records of 876 patients who underwent transthoracic needle aspirations between January 1981 and February 1986. Among these patients, 212 (24%) sustained a pneumothorax, and 92 (11%) required placement of a small 9-French chest tube attached to a flutter-type (Heimlich) valve. Duration of chest-tube drainage ranged between 24 hr and 3 weeks (mean, 2.2 days). Complete resolution of the pneumothorax and subsequent removal of the chest tube after 24 hr of drainage occurred in 38 (41%) of the 92 patients. Twenty-nine (32%) required 48 hr of drainage, and nine (10%) required 3 days. The remaining 16 (17%) required longer periods of drainage ranging from 4 days to 3 weeks. The tubes of six of this last group of patients were attached to a suction apparatus, and three of these patients eventually had a 28-French chest tube placed surgically. No significant complications occurred. The use of a small chest tube for treatment of pneumothorax after transthoracic needle aspiration is easy, safe, and efficacious.

Pulmonary arteriography in the high-risk patient

Pulmonary arteriography is an invasive but relatively safe diagnostic procedure. It is generally believed that the presence of pulmonary hypertension is one risk factor that increases the likelihood of a major complication. To assess the magnitude of risk, the reports on 1,434 patients who underwent pulmonary arteriography were retrospectively reviewed, and the occurrence of complications in the 388 (27%) patients with pulmonary hypertension was noted. Major complications related to contrast material injection (excluding allergic reactions) occurred in 30 (2%) of the 1,434 examinations and included two deaths from acute cor pulmonale. Six complications occurred in the 388 patients with pulmonary hypertension and/or elevated right ventricular end-diastolic pressure (RVEDP). The two deaths occurred in patients with severe pulmonary hypertension and elevated RVEDP. Most patients with severe cardiopulmonary compromise tolerated angiography well. The increased risk of studying this group of patients is modest and must be weighed against the potential therapeutic benefits to the patient.

Percutaneous balloon dilatation of ureteral strictures

Percutaneous balloon dilatation of ureteral strictures has not gained widespread acceptance, despite proven success with the techniques for dilating stenotic blood vessels. Thirty-one ureteral strictures (in 30 patients) that were dilated during a 42-month period were reviewed to assess the results and to determine which patients are most likely to benefit from the procedure. Eighteen (58%) of 31 strictures were successfully dilated and remained patent for at least 6 months. Thirteen (42%) of 31 strictures resulted in failed patency either immediately (two patients) or within 3 months (seven patients), 6 months (three patients), or 21 months (one patient). Fourteen (64%) of 22 strictures less than 7 months of age were successfully dilated. All dilations for strictures more than 7 months of age failed. Four strictures were of unknown age. Nine (69%) of 13 strictures located in the proximal or midureter remained patent, and three (60%) of five dilations at a ureteroileal anastomosis were successful. Neither of two strictures at a ureterocolic anastomosis was treated successfully. We conclude that percutaneous balloon dilatation is an effective treatment of ureteral strictures in some patients, especially when the strictures are less than 7 months of age.

Infectious complications of percutaneous biliary drainage

The infectious complications of percutaneous biliary drainage were reviewed in 132 patients with obstructive jaundice. Cholangitic or septic episodes occurred more frequently in patients with malignant (54%) than in those with benign (22%) disease, and frequently were not related to catheter insertions or manipulations. The frequency and mechanisms of bacterial colonization of bile and blood in patients with obstructive jaundice before and after biliary drainage are reviewed. The significant morbidity and mortality related to postdrainage infectious episodes is stressed, and the efficacy of antibiotic prophylaxis is discussed. The significant risks and complications of percutaneous biliary drainage must be considered prior to catheter placement, particularly in the most debilitated patients.

Digital indirect portography

Thirty-eight patients underwent digital indirect portography with arterial injections of dilute contrast medium. The portal system was seen in 37 patients. Compared with conventional portography, the technique offers many advantages, including increased sensitivity and earlier visualization of the portal venous system, lower contrast loads, and lack of need for vasodilators. Digital indirect portography is an excellent method for evaluating the portal venous system.

Timing of chest film follow-up after transthoracic needle aspiration

Transthoracic needle aspiration of pulmonary lesions is an extremely common procedure. Pneumothorax, the most common complication, is potentially life threatening. In an effort to determine the optimum time for obtaining chest radiographs to detect pneumothorax, all cases of pneumothorax that occurred after transthoracic needle aspiration between 1981 and 1984 were reviewed. During this period, 673 transthoracic-needle-aspiration procedures were performed. Pneumothorax occurred in 160 patients (23.8%), and 78 (11.5%) of these required a chest tube or aspiration. Of the total number of pneumothoraces, 142 (89%) were detected immediately, 15 (9%) were first seen after 1 hr, and only 3 (2%) were first seen on the 4-hr radiograph. Of the pneumothoraces requiring intervention, 69 (88%) were detected immediately while the remainder were first picked up after 1 hr. There were no significant pneumothoraces detected after the 1-hr radiograph. Immediate fluoroscopy and a routine chest radiograph 1-hour postprocedure are recommended. For outpatients 1-hr and 4-hr follow-up radiographs should be taken.

Encapsulation of proteins and peptides in milkfat: encapsulation efficiency and temperature and freezing stabilities

Encapsulation of aqueous protein solution was most efficient when the butter and protein solution emulsion was at 58 degrees C before dispersion into water, although encapsulation efficiencies were high between 46 and 66 degrees C. Capsules could be produced with no emulsifiers and an emulsion temperature of 66 degrees C but no capsules were formed when emulsion temperature was lowered to 38 degrees C. Capsules with encapsulated beta-casein peptides and with proteose peptone had similar low-temperature stabilities with a loss of about 10 per cent of the peptides after 24 h at 4 degrees C. However, capsules with beta-casein peptides were slightly more stable above 26 degrees C. Little diffusion of the haemoglobin from capsules occurred at less than 20 degrees C but above 32 degrees C capsules destabilized and the haemoglobin diffused out of the capsules. Capsules were stable after freezing at -90 degrees C and -18 degrees C and could be thawed and redispersed; a 15-25 per cent loss of capsules was observed during freezing. Concentrating capsules by removing all or one-half of the dispersion fluid did not increase stability to freezing.

Fine needle aspiration biopsy in malignant obstructive jaundice

Percutaneous cytodiagnosis of malignancy in patients with biliary tract obstruction is often useful in planning subsequent therapy. Of 121 patients presenting for percutaneous transhepatic cholangiography and biliary drainage, 45 had fine needle aspiration biopsies. Forty-one patients had malignant obstruction of the biliary tree, while benign disease was present in 4 patients. Neoplasia was diagnosed in 12 of 13 patients with bile duct carcinoma, 16 of 22 patients with pancreatic cancer, and 3 of 6 patients with other malignancies. Radiologic biopsy sensitivity was only slightly inferior to surgical biopsy sensitivity in the same patient population. A scheme for biliary cytodiagnosis is presented, which uses a percutaneous approach for patients with suspected pancreatic carcinoma and a transcatheter approach for patients with suspected bile duct carcinoma. The utility of this procedure and the low complication rate are stressed.

Ultrasonically guided percutaneous transhepatic transcholecystocholangiography in the nondilated biliary tree

Five patients with CT or ultrasound-proven nondilated intrahepatic biliary radicles underwent ultrasound-guided percutaneous transhepatic transcholecystocholangiography (PTHTCC) for visualization of the biliary tree following failed endoscopic retrograde cholangiography. In no instance were more than 2 passes of a 22-gauge needle necessary to enter the gallbladder. Visualization of the biliary tree was excellent in all cases, and there were no complications. Therefore, PTHTCC is a safe and reliable method of visualizing the nondilated biliary tree.

Complications of percutaneous nephrostolithotomy

In 224 patients, renal stones were removed from the urinary tract using either direct extraction with a basket or forceps (59 patients), ultrasonic lithotripsy (164 patients), or infusion chemotherapy (one patient). Residual stone fragments were present more frequently in patients treated with ultrasonic lithotripsy (27%) than with direct extraction (5%). Other complications included hemorrhage (eight patients), catheter dislodgement (four patients), large amounts of urine extravasation (three patients), glycine ascites (three patients), infection (two patients), pneumothorax (one patient), and a prolonged ileus (one patient). More complications occurred among the first 50 patients than the last 50 patients, even though more difficult cases, including patients with staghorn calculi, were accepted during the latter period. Although a learning curve exists, complications can be minimized by attempting to treat more favorable cases during the initial experience.

Intravenous digital subtraction angiography in the preoperative evaluation of renal masses

Intravenous digital subtraction angiography (DSA) was performed in 23 patients with renal masses to document tumor extension into the main renal vein or inferior vena cava. The DSA findings were compared with computed tomographic as well as surgical and pathologic findings. Additional data regarding the number of renal arteries present and the relative vascularity of the tumor were also gathered. DSA documented 17 true-negative renal veins, three true-positive renal veins, and one false-negative renal vein. Two patients could not hold their breath long enough to evaluate the renal vein. In 17 of 19 cases, single renal arteries to the affected kidney were correctly identified. In three patients, two renal arteries to the involved kidney were correctly identified. The renal masses were avascular in two patients, hypovascular in five, moderately vascular in eight, and hypervascular in seven. In one case the mass was out of the field of view, and vascularity was not evaluated. In these patients, DSA was an accurate and relatively noninvasive method to assist in the preoperative evaluation of renal masses.

Nitrous oxide: effective analgesic for vascular and interventional procedures

During a 2 year period nitrous oxide was used as a sole or supplementary analgesic during 173 vascular or interventional procedures including peripheral angiography and endourologic and endobiliary procedures. The decision to administer nitrous oxide to a given patient was a matter of physician preference. Patients with bowel obstruction, pneumothorax, or chronic obstructive pulmonary disease were excluded from this method of analgesia. The nitrous oxide was administered by a radiology nurse under the supervision of an attending radiologist. Nitrous oxide was used without premedication for 39 procedures and with premedication (usually meperidine 1 mg/kg, promethazine 0.3 mg/kg, or atropine 0.01 mg/kg) in 134 procedures. In 74% of nonpremedicated individuals analgesia was adequate with nitrous oxide alone; 26% required supplemental intravenous medication. In 61% of premedicated individuals pain relief was adequate with nitrous oxide; 39% required supplemental intravenous medication. Complications, including nausea, vomiting, and agitation, occurred in eight patients, but were minor and easily reversed by decreasing the concentration of nitrous oxide. Nasally administered nitrous oxide is a safe, easily used, and effective analgesic.

Percutaneous transluminal angioplasty vs. surgery for renovascular hypertension

Therapeutic results in 102 hypertensive patients were evaluated after either renal artery percutaneous transluminal angioplasty (PTA) or surgical bypass procedures for renovascular hypertension. A minimum of 6 months of follow-up was accepted to evaluate therapeutic success or failure. Renal angioplasty had a beneficial result in each of 13 patients with fibromuscular dysplasia and in 10 (83%) of 12 patients with atherosclerotic lesions that did not involve the origin of the renal artery. Although surgery was also beneficial in each of six patients with fibromuscular dysplasia, it helped only five of 10 patients with atherosclerosis of the renal artery. Angioplasty results were similar to surgical results for atherosclerotic lesions that involved the origin of the renal artery. Angioplasty was unsuccessful in two cases of neurofibromatosis because of the firm nature of the lesions, where a bypass procedure was successful in one case. Major complications were more common in surgical cases than in angioplasty. PTA is recommended for all renal artery lesions; surgery should be reserved for failed PTA or recurrent renal artery stenosis after PTA.

Biliary cytodiagnosis. Bile sampling for cytology

The records of 121 patients who presented for PTC and biliary drainage within a five-year period were reviewed. Fifty-eight bile samples had been obtained from 38 of these patients for cytologic analysis. Malignancy was detected in 14 of 32 patients with carcinoma (sensitivity 44%). Repeat sampling was positive in four of nine patients whose initial specimen contained no tumor cells. Bile duct carcinoma, pancreatic carcinoma, and metastatic disease were all detected. An approach to biliary cytodiagnosis is offered that, it is hoped, will further minimize future false negative results.

Technique to facilitate percutaneous nephrostomy in non-obstructed kidneys

A technique for performing antegrade pyelography during nephrotomy is described--puncture with a 21-gauge, 20-cm Cope needle, placement of a 0.018-inch SMG mandril "coat-hanger"-shaped guidewire, with the needle exchanged for a 3-French multi-sidehole dilator. Use of the 3-French dilator provides more security and less trauma to the renal pelvis; nephrotomy time is also curtailed. In 25 patients the technique was used successfully with 2 minor complications.

Percutaneous approach to nephrolithiasis

Percutaneous techniques were successful in removing stones from 101 (92%) of 110 kidneys attempted. Ultrasonic lithotripsy was used on 80 kidneys in 74 patients with stones 5-38 mm in diameter. The most common complication was incomplete disintegration with retained stone fragments. Twenty patients were treated by direct stone extraction, either by a stone basket or forceps. The average hospitalization for percutaneous stone removal of 10 days was not significantly different from that for open nephrolithotomy. However, patients undergoing percutaneous stone removal had only a 3-10 day convalescence after hospital discharge before returning to normal activity.

CT assistance for fluoroscopically guided transthoracic needle aspiration biopsy

Five cases are presented that illustrate the utility of obtaining limited CT prior to fluoroscopically guided biopsy in patients who have lung or mediastinal lesions that cannot be adequately localized by chest radiography. Each case describes a unique setting in which the CT images facilitate accurate and safe biopsy needle placement. The rare requirement for biopsy using CT alone, which can be considerably more time consuming, is emphasized.

Ventilation-perfusion scanning and pulmonary angiography: correlation in clinical high-probability pulmonary embolism

During a 3-year period, 173 clinically selected patients underwent pulmonary angiography to confirm or exclude acute pulmonary embolism. All patients had undergone ventilation-perfusion (V/Q) scanning (167 patients) or perfusion scanning alone (six) before angiography. Angiography was done because the results of the V/Q scanning did not satisfy the clinician's needs for certainty. The results of the V/Q and studies were compared to determine the relative accuracy of V/Q scanning in this clinical setting. Pulmonary embolism was found in seven (15%) of 47 patients with low-probability scans, 11 (32%) of 34 patients with intermediate-probability scans, 22 (39%) of 57 patients with indeterminate scans, and 23 (66%) of 35 patients with high-probability scans. In this clinically selected population, low-probability scans were more accurate in excluding pulmonary embolism than were high-probability scans in establishing that diagnosis.

Intraarterial digital subtraction angiography in hypertensive azotemic patients

Ten intraarterial digital subtraction angiography studies in nine azotemic patients were reviewed to assess the technical adequacy and the effect of contrast load on renal function. All studies were of diagnostic quality. In only two of 10 studies was there a mild transient deterioration in the degree of renal insufficiency. Intraarterial digital subtraction angiography is a reliable method that can be used to evaluate the renal arteries, even in the presence of azotemia.

Percutaneous transluminal angioplasty in diabetic patients: an effective treatment modality

Percutaneous transluminal angioplasty (PTA) was performed for nonhealing ulcers, severe claudication, or rest pain in 10 patients with diabetes mellitus. Twenty-two atherosclerotic lesions were dilated in 15 extremities, including 16 iliofemoral arteries and 6 superficial femoral arteries. The procedure was technically successful in all patients and 8 of 9 (89%) with clinical follow-up showed improvement clinically after the procedure. Diabetes is not a contraindication to PTA; rather this modality can be used effectively to control and treat peripheral vascular insufficiency in diabetic patients.