Afferent loop syndrome: sonographic findings in seven cases

We studied the sonographic findings in seven patients in whom afferent loop obstruction was first detected by sonography. All seven subsequently were proved at surgery to have afferent loop syndrome. The causes of the obstruction included internal hernia (n = 3), cancer recurrence (n = 2), marginal ulcer (n = 1), and development of cancer at the anastomosis site (n = 1). In all cases, the dilated afferent loop was seen on sonography as a tubular structure in the upper abdomen crossing transversely over the midline. The distal end of the afferent loop could be traced toward the anastomosis. The probable cause of the syndrome was predicted on the basis of sonography in two of three patients with cancer at the anastomosis. Our experience suggests that afferent loop syndrome can be diagnosed sonographically on the basis of the detection, location, and shape of the dilated afferent loop.

Routine contrast enhancement for cranial magnetic resonance imaging: an analysis of its diagnostic value in adults

This study evaluated the diagnostic value of contrast enhancement in consecutive adults referred for cranial magnetic resonance imaging (MRI). All of the 112 participating patients underwent two sets of studies, first without and then with a contrast medium. Three neuroradiologists independently reviewed the information for each patient. Contrast enhancement contributed diagnostically useful information in 75% of cases: in 4% because undiagnosed lesions became apparent, in 26% because more information was obtained regarding the size, extent or margins of a lesion and in 45% because the lack of contrast enhancement in the area of interest allowed more confident exclusion of disease in patients with compelling clinical findings or demonstrated the nonaggressive nature of a lesion apparent with unenhanced MRI. The authors conclude that contrast enhancement is diagnostically useful for most patients referred for cranial MRI. Although the proportion of cases in which contrast enhancement was useful was much higher than in previous studies conducted in the United States, the authors believe that this finding is due to the high prevalence of disease in the population referred to this Canadian MRI centre.

Molecular cloning and sequence analysis of cDNAs for five major subunits of human proteasomes (multi-catalytic proteinase complexes)

Proteasomes are multicatalytic proteinase complexes consisting of a set of non-identical polypeptide components. Of these multiple components, the nucleotide sequences of five major subunits (named HC2, HC3, HC5, HC8 and HC9) of human proteasomes have been determined from recombinant cDNA clones by screening a human HepG2 hepatoblastoma cell cDNA library with rat proteasome cDNAs isolated previously as probes. The polypeptides deduced from their nucleotide sequences consisted of 263, 234, 241, 255 and 261 amino acid residues with calculated molecular weights of 29,554, 25,897, 26,487, 28,431 and 29,482, respectively, which are encoded by single independent genes. The primary structures of these subunits of human proteasomes closely resemble those of their rat counterparts and show considerably high inter-subunit homology, although the homology of HC5 is relatively low. These findings, together with the structural similarities of other eukaryotic proteasomes including those of Drosophila and yeast (Saccharomyces cerevisiae) support and extend the previously proposed concept that eukaryotic proteasome genes form a multi-gene family with the same evolutionary origin.

Optic neuritis and orbital lesions: lipid-suppressed chemical shift MR imaging

A derivative of the Dixon method, chopper fat suppression, was used in the magnetic resonance imaging evaluation of 40 patients: 37 with suspected optic nerve lesions, predominantly optic neuritis, and three with orbital lesions. In patients with optic neuritis, the technique was sensitive, allowing detection of 29 of 34 visual-evoked-response-confirmed lesions on T2-weighted lipid-suppressed images. There were no false-positive studies. Sensitivity for detection of optic neuritis was 89%; specificity, 100%; and accuracy, 86%. The technique was also useful for depicting inflammatory changes in the orbital apex due to fungal abscess and confirming the fatty nature of an extraconal dermoid tumor. A slight increase in noise and mild accentuation of susceptibility effects at interfaces of air, bone, and brain did not degrade images significantly. The chopper-based technique requires only standard imaging time and has usual spin-echo sensitivity. The results are comparable to short-inversion-time inversion-recovery imaging, without the constraints of sequence limitations or artifacts at fat and water interfaces.

Molecular cloning of the yeast proteasome PRS2 gene identical to the suppressor gene scl1+

The YC7-alpha gene encoding a subunit of yeast proteasomes named PRS2 has been isolated and sequenced. Southern blot analysis after electrophoretic separation of yeast chromosomal DNAs showed that the PRS2 gene is located in chromosome VII, unlike the PRS1 gene for subunit YC1, is located on chromosome XV. Surprisingly, the overall structure of the PRS2 gene was found to be identical to that of the suppressor scl1+ gene restoring the SCL1-1 mutation that suppresses crl3 cycloheximide-resistant, temperature-sensitive lethality. The identity of these two genes indicates that the suppressive role of the scl1+ gene product on crl3 mutation could be attributed to proteasomal function.

Mechanisms of contrast enhancement in magnetic resonance imaging

The use of contrast agents has increased the sensitivity and specificity of magnetic resonance imaging (MRI). Contrast in MRI is multifactorial, depending not only on T1 and T2 relaxation rates, but also on flow, proton density and, in gradient-echo sequences, on the angle of the induced field. The use of contrast agents in MRI changes the T1 and T2 relaxation rates, producing increased signal intensity on T1-weighted images or decreased signal intensity on T2-weighted images, or both. All contrast agents produce changes in magnetic susceptibility by enhancing local magnetic fields. These effects are caused by interactions between nuclear and paramagnetic substance magnet moments, which produce accentuated transitions between spin states and cause shortening of T1; the paramagnetic substance causes accentuated local fields, which lead to increased dephasing and thus shortening of T2 or T2* relaxation time. The efficacy of shortening of T1, T2 or T2* relaxation time depends on the distance between the proton nucleus and the electronic field of the paramagnetic compound, the time of their interaction (correlation time) and the paramagnetic concentration. The MRI contrast agents currently in use cause shortening of T1, T2 or T2* relaxation time. Metal chelates (e.g., gadolinium-diethylene triamine penta-acetic acid [Gd-DTPA]) in low concentration cause shortening of T1 relaxation times, and the superparamagnetics (e.g., ferrite) cause shortening of T2 relaxation times.

Magnetic resonance imaging of facial nerve neuromas

Facial nerve neuromas are uncommon tumors often confused with other tumors of the temporal bone and cerebellopontine angle. Radiologically, it may be impossible to differentiate an intracanalicular facial nerve neuroma from an acoustic neuroma. We present three case reports of facial nerve neuromas arising within the internal auditory canal to show the important magnetic resonance imaging features of these tumors. One tumor extended into the cerebellopontine angle, middle cranial fossa, and middle ear. Another filled the internal auditory canal and extended through the cerebellopontine angle to the brain stem. The third occurred in a patient who had neurofibromatosis as well as numerous other intracranial tumors. We feel that gadolinium-enhanced magnetic resonance imaging provides the most useful information in the preoperative assessment of this disorder.

Arteriovenous malformations of the brain: recent results of endovascular therapy

Results of embolization and subsequent surgical resection were reviewed in 38 patients with arteriovenous malformations (AVMs) of the brain during the past 3 years. Advanced techniques were used for embolization, including real-time digital subtraction angiofluoroscopy; directable microcatheters; and a mixture of microfibrillar collagen, polyvinyl alcohol sponge microparticles, and ethanol, in addition to acrylic glue. Embolization caused a permanent deficit in four patients (10.5%) (quadrantanopia [n = 3], cerebellar ataxia [n = 1]). Thirty-two patients (84%) underwent surgery after embolization, and 28 (74%) were completely cured, as assessed with postsurgical angiography. Twenty-five patients (66%) had either no deficit or no change in deficit after treatment. Two patients had worsening of a previous deficit after postembolization resection, two patients had mild weakness not previously present, and five patients had visual field defects. One patient developed Gerstmann syndrome after resection, and one patient with ataxia after embolization also had ataxia after surgical resection. Two patients died of complications due to surgical resection. Most of the AVMs in this series were large and complex. Embolization used predominantly as a preoperative procedure enabled complete resection, as achieved in the majority of these cases.

cDNA cloning and sequencing of component C8 of proteasomes from rat hepatoma cells

The primary structure of component C8 of rat proteasomes (multicatalytic proteinase complexes) has been determined by sequencing on isolated cDNA clone. C8 consists of 255 amino acid residues with a calculated molecular weight of 28,417. These values are consistent with those obtained by protein chemical analyses. Computer-assisted homology comparison showed that C8 is a new protein, differing from all proteins reported so far. The overall amino acid sequence of C8 resembles those of most other components of proteasomes reported, such as components C2, C3 and C9 of rat proteasomes and certain components of other eukaryotic proteasomes, such as those of Drosophila and yeast, but shows little similarity with component C5 of rat proteasomes. C8 showed particularly close structural similarity to component YC1 of yeast proteasomes, suggesting that C8 has been highly conserved during evolution and functions ubiquitously in all eukaryotes.

Oriental cholangiohepatitis: sonographic findings in 48 cases

Oriental cholangiohepatitis is characterized by recurrent attacks of abdominal pain, fever, chill, and jaundice and grossly dilated extrahepatic and intrahepatic ducts containing soft, pigmented stone and pus. Sonograms were studied in 48 patients in whom the diagnosis was later proved during surgery (n = 34) or on the basis of clinical and laboratory findings and endoscopic retrograde cholangiography (n = 14). The sonographic findings included intrahepatic and/or extrahepatic bile duct stones (n = 47); moderate to severe dilatation of the extrahepatic ducts with relatively mild or no dilatation of intrahepatic bile ducts (n = 41); localized dilatation of the lobar or segmental bile ducts, especially the left hepatic lobe (n = 16); and gallstones (n = 22). Our experience suggests that the preoperative diagnosis of oriental cholangiohepatitis can be strongly suggested by sonographic findings.

Differences in blood pressure levels obtained by auscultatory and oscillometric methods

Levels of blood pressure measured by the conventional auscultatory method were compared with those measured by the Dinamap Monitor (Dinamap Monitor 1846 SX, Critikon Inc, Tampa, Fla), an oscillometric device. Triplicate measurements were obtained by the two methods 10 to 15 minutes apart in 381 seated fifth-grade children, ages 10 to 13 years. The width of the air bladder of the blood pressure cuff was selected to be 40% to 50% of the circumference of the upper arm. The mean systolic and diastolic pressures (at the fourth phase of Korotkoff sounds) by the auscultatory method were 6.4 mm Hg lower and 8.7 mm Hg higher than the oscillometric systolic and diastolic blood pressures, respectively. The findings of this study suggest that published normative levels of auscultatory blood pressure may be inappropriate as a standard when blood pressure measurement is obtained by the Dinamap Monitor. Until a new set of normative Dinamap blood pressure levels becomes available, one should use equations (A = 12.8 + 0.82D for systolic, and A = 34.3 + 0.54D for diastolic blood pressures at the fourth phase of Korotkoff sounds, where A is auscultatory blood pressure and D is Dinamap blood pressure) to predict auscultatory blood pressures before Dinamap blood pressures are compared with normative auscultatory blood pressure levels.

Medial extent of the posterior renal fascia. An anatomic and computed tomography study

To study the medial extent of the posterior renal fascia and the perirenal space, the authors dissected two cadavers and reviewed 50 computed tomographic (CT) abdominal scans. The results demonstrated that the medial extent of the posterior renal fascia depends on the level in a vertical direction and its relationship to the kidney which varies at different levels. At the renal hilus, the fascia inserts posteromedially to the fascia of the quadratus lumborum along its lateral margin; more cranially, the line of insertion is more lateral, onto the diaphragmatic fascia; more caudally, the line of insertion is more medial, inserting onto the anterior surface of the quadratus lumborum. Therefore the posteromedial insertion of the posterior renal fascia extends medially, from the more laterally placed diaphragmatic fascia, to the lateral margin of the quadratus lumborum and then to the anterior surface of the quadratus lumborum, depending on the anatomic level. The clinical implication of these findings are discussed.

Central lesions in chronic inflammatory demyelinating polyneuropathy: an MRI study

To determine the frequency of the possible association between chronic inflammatory demyelinating polyneuropathy (CIDP) and MS, we did magnetic resonance imaging (MRI) of the brain in 19 patients with CIDP. Only 1 patient had clinical signs suggestive of central involvement. Seven of the 19 scans showed 2 or more brain "lesions." In 1 case the cause was an infarct and in 5 cases the patients were over 55 years of age and the lesions were not typical of MS. One 38-year-old patient had 2 small subcortical lesions. Typical MS lesions on MRI are uncommon in CIDP.

Sonographic detection of pneumoperitoneum in patients with acute abdomen

We describe five patients who presented with an acute abdomen in whom pneumoperitoneum was first detected by sonography. All five subsequently were proved to have a perforated viscus. In all cases, the pneumoperitoneum was seen as an echogenic line with a posterior ring-down or reverberation artifact between the anterior abdominal wall and the anterior surface of the liver. The finding was shown best in the right upper quadrant with the patient in the left lateral decubitus position. The echoes caused by the pneumoperitoneum overlapped the echoes of the lung during inspiration, but the echoes were separate during expiration. The probable cause of pneumoperitoneum was determined with sonography in four of the five patients: three had perforation of duodenal ulcer and one had perforation of gastric cancer. The fifth patient had a perforated ileum, which was not evident on the sonogram. Our experience with these patients suggests that the detection of pneumoperitoneum on sonography in patients with an acute abdomen is an important sign of a perforated viscus.

MR imaging after surgery for vertebrobasilar aneurysm

We examined the safety and utility of high-field MR in patients who had surgery for cerebral aneurysms of the vertebrobasilar system. Eighteen posterior (and three coincidental anterior) circulation aneurysms were treated. Twenty-one MR scans were obtained at a mean postoperative interval of 7.2 days. The mean size of the preoperative vertebrobasilar aneurysm was 2.2 cm; six were giant (greater than 2.5 cm) and eight were large (greater than 1.5, less than or equal to 2.5 cm). In 17 patients, Sugita nonmagnetic clips were used. In one other, a Drake tourniquet was used. No ill effects occurred from scanning with a high-field imaging unit at 1.5 T. The MR clip artifact was much less obtrusive than that on CT. In 11 cases, the aneurysm could be partially imaged postoperatively, mainly in very large aneurysms or in those treated by clipping the parent vessel. Of these, two revealed residual lumina on MR and nine looked completely thrombosed. Postoperative angiography showed that in four of the thrombosed-appearing aneurysms a residual lumen with a mean diameter of 1.0 cm had been missed. In the patient imaged after application of a Drake tourniquet, no artifact was seen, and a good assessment of progressive partial thrombosis was obtained. Evolution of the signal intensity of new aneurysm thrombus, in those minimally or not obscured by artifact, coincides with patterns previously described for hemoglobin in intracerebral hematomas. The earliest hyperintensity could be seen in either the periphery or the center of the new thrombus. All 15 patients examined with new postoperative deficits showed appropriate lesions, mainly small brainstem ischemic foci. Postoperative CT (performed in all but four of these patients) missed over 80% of these lesions, mainly owing to artifact from clip or bone. We conclude that MR is better than CT in the postoperative assessment of aneurysm patients, particularly in demonstrating small zones of ischemia. High-field MR scanning is safe if nonmagnetic surgical clips are used. MR is not accurate in assessing residual lumina.

Neuropathologic correlates of leuko-araiosis

We describe the pathologic findings in 17 persons with dementia, 12 of whom exhibited leuko-araiosis on computed tomographic scan. The presence of white matter pallor was confirmed on autopsy in 11 of these 12 cases, 9 with Alzheimer's disease and 2 with multi-infarct dementia. Two further patients, 1 with Alzheimer's disease and 1 with multi-infarct dementia, proved to have white matter changes on pathologic examination. White matter pallor coexisted with cerebral amyloid angiopathy in the brains of the patients with Alzheimer's disease. The presence of severe white matter pallor in patients with Alzheimer's disease correlated with early death, while the presence of cortical scars was associated with prolonged survival. Because early death in patients with Alzheimer's disease has been linked with severe pathologic and chemical changes, the presence of white matter pallor may be further evidence of a particularly severe process in patients with early onset of Alzheimer's disease.

Oncogene expressions detected by in situ hybridization of squamous metaplasia, dysplasia and primary lung cancer in human

In order to elucidate the dynamic changes of oncogene expression in the sequential cascade of squamous metaplasia, dysplasia, and squamous cell carcinoma of the bronchial epithelium, hybridization in situ was employed with a biotinylated oncogene probe. The expression of c-myc was localized exclusively in nuclei. While normal bronchial epithelium revealed no discernible clumps of c-myc grains, except occasional grains less than 3 per cell, squamous metaplasia showed increased number of grains and a few clusters of c-myc grains. In dysplasia, c-myc expression was more intensive than in squamous metaplasia. Approximately, 1/3 to 2/3 of tumor cell populations of squamous cell carcinomas of the lung revealed tremendously increased c-myc expression. In addition clumpy grains of c-myc in squamous cell carcinoma appeared more frequently than in squamous metaplasia or dysplasia. The c-myc expression was found to vary between different samples and within each cancer, and not all cancer cells expressed c-myc. These data indicate that c-myc oncogene plays it's role on reprogramming for growth control of cell populations particularly in multistage carcinogenesis and progression of lung cancer. These dynamic alterations of c-myc expression suggest that neoplastic transformation may occur conceivably at the dysplastic phase eventually resulting in carcinoma in situ. This means, in turn, squamous dysplasia is a putative precancerous lesion of the human lung.

Pigmented cells of the stria vascularis and spiral ligament of the chinchilla

This study was designed to investigate the cellular distribution and ultrastructure of melanin pigment in the stria vascularis and spiral ligament of the chinchilla cochlea. Typical dendritic melanocytes containing homogeneously distributed eumelanin granules were observed in the spiral ligament. In the stria vascularis melanin was found to occur in three types of cells (heavily pigmented cells that appear to be melanocytes, intermediate cells and basal cells). The melanocyte-like cells contain pigment globules composed of melanin granules, granular matrix and occasional lipid droplets in a configuration similar to that of neuromelanin. These cells are morphologically distinct from intermediate cells which contain sparsely distributed, small, dense granules apparently composed of melanin. The intermediate cells show a positive DOPA reaction and portions of the intermediate cell GERL system display intense acid phosphatase reactivity. The basal cells of the chinchilla stria were also found to contain occasional clusters of melanin granules. It is hypothesized that the basal cells may acquire melanin by donation from the other pigmented cells of the lateral cochlear wall.

Platelet monoamine oxidase in Parkinson patients: effect of L-deprenyl therapy

Platelet MAO activity was measured in 79 Parkinson patients (56 males and 23 females) before and during L-deprenyl therapy. Baseline platelet MAO activity was higher in females than in males with no age dependent differences. During chronic L-deprenyl therapy, MAO activity was inhibited greater than 98%. Four hours after the oral administration of the first 5 mg dose of L-deprenyl, platelet MAO activity was inhibited by 86%. By 24 hours, greater than 98% inhibition was achieved and this degree of inhibition was maintained during continuous L-deprenyl administration. Following oral administration of 10 mg L-deprenyl once a day versus 5 mg L-deprenyl twice a day, the time course of platelet MAO inhibition was similar. Five days after the termination of chronic L-deprenyl therapy, platelet MAO activity was still inhibited by 96%. MAO activity returned to normal by 2 weeks after stopping L-deprenyl. Platelet MAO activity is a useful method of monitoring bioavailability, compliance, dose-response relationship and optimal dosage schedules for L-deprenyl in Parkinson patients.

Experimental cholesteatoma. Epidermal ingrowth through tympanic membrane following middle ear application of propylene glycol

This study was designed to investigate morphological changes in the tympanic membrane (TM) associated with cholesteatoma formation in experimental animals following application of propylene glycol to the middle ear. A 50% solution of propylene glycol was applied bilaterally to the middle ear cavities of 30 young-adult chinchillas. The animals were sacrificed for light and electron microscopic study at intervals of 2 days to 6 weeks after a single application of 0.2 ml of the propylene glycol solution. At 2 days there was complete destruction of the epidermal and mucosal layers of the TM. The denuded lateral surface rapidly became re-epithelialized by hyperplastic epidermal cells and by 2-3 weeks, keratinizing epidermis penetrated damaged areas of the fibrous layer of the lamina propria to reach the medial surface of the TM. These epidermal cells proliferated in the middle ear cavity, forming cholesteatomas. Our observations indicate that invasion of the intact, but structurally altered, tympanic membrane by hyperplastic epidermis is a primary mechanism of cholesteatoma formation in the animal model.

Biliary cystadenoma and cystadenocarcinoma: CT and sonographic findings

Eight women (ages 18-65 years; mean, 47 years) with biliary cystadenoma (n = 3) or cystadenocarcinoma (n = 5) were examined with computed tomography and sonography. The appearance of the tumors varied from unilocular cystic masses to multilocular cystic masses with multiple satellite tumors, although the majority (n = 6) of tumors were single, multilocular, and cystic. Cystic areas showed attenuation numbers under +30 HU. Papillary excrescences, nodular thickening of internal septa, and mural nodules, which showed contrast enhancement, were seen in one case of cystadenoma and all five cases of cystadenocarcinoma. One cystadenoma and one cystadenocarcinoma contained calcifications. Three cases showed connection to the intrahepatic bile ducts. Biliary cystadenoma and cystadenocarcinoma should be the primary diagnostic consideration when one detects in a middle-aged woman a well-encapsulated, multilocular cystic mass connected to the biliary system or prolapsing into the bile duct.

Clonorchiasis: sonographic findings in 59 proved cases

Clonorchiasis is a parasitic disease of the bile ducts that occurs in endemic areas after ingestion of the raw flesh of freshwater fish. We analyzed the sonographic findings in 59 patients with clonorchiasis, suspected prospectively from sonographic findings and proved subsequently by demonstration of eggs in their stools. Diffuse dilatation of the small intrahepatic bile ducts with no or minimal dilatation of the large intra- and extrahepatic ducts was observed in all cases. The extrahepatic ducts were patent throughout in all except one case. This characteristic finding reflects diffuse intrahepatic bile duct obstruction and resultant proximal dilatation caused by an adult worm or aggregates of worms, as worms reside diffusely in the medium and small intrahepatic bile ducts. Cholangitis and multifocal periductal fibrosis with proximal dilatation may play an additional role. Increased echogenicity of the intrahepatic bile duct wall was present in 39 cases (66%), reflecting cholangitis and periductal fibrosis. In 17 cases (29%), floating or dependent, discrete, nonshadowing, intraluminal, echogenic foci caused by adult worms in the bile were demonstrated in the gallbladder. These echogenic foci were distinguished from stones because they were fusiform, weak in echogenicity, and floated with a change in position. Clonorchiasis should be considered when sonography discloses the characteristic pattern of bile duct dilatation with increased wall echogenicity and nonshadowing, discrete, echogenic foci in the gallbladder lumen.

Normative arm and calf blood pressure values in the newborn

Indirect BP measurement was obtained in the right upper arm in 219 healthy newborn infants with the Dinamap monitor and was compared with values obtained from the calf to establish normative BP values and to help establish a diagnosis of hypertension and coarctation of the aorta in the newborn. There were 174 Mexican-Americans (79.5%), 33 whites (15.0%), and 12 blacks (5.5%). The width of the BP cuff was selected to be 0.4 to 0.5 times the circumference of the extremities. Three supine position readings of BPs and heart rate were obtained from each site and were averaged for statistical analyses. Mean arm BP values (+/- SD) of the neonate less than 36 hours of age were 62.6 +/- 6.9/38.9 +/- 5.7 mm Hg (48.0 +/- 6.2 mm Hg). Neonates older than 36 hours had slightly but significantly (P less than .05) greater values (4 to 6 mm Hg) than did infants younger than 36 hours of age. Active neonates had values 6 to 10 mm Hg greater than quiet neonates (P less than .05). BP values in the calf obtained with the same-sized cuff were almost identical with those obtained from the arm. Differences in consecutively obtained arm and calf BPs (arm values minus calf values) were 1.1 +/- 7.7 mm Hg systolic, -0.01 +/- 6.2 mm Hg diastolic, and 0.9 +/- 6.9 mm Hg mean pressures. Mean heart rate (+/- SD) of neonates less than 36 hours of age was 129.4 +/- 13.2 beats per minute and that of neonates older than 36 hours of age was 139.4 +/- 14.1 beats per minute.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of three embolic agents in pig rete

In ongoing research into potential embolic agents, three substances were evaluated for their effectiveness in occluding the pig rete. Selective injection of these agents produced varying degrees of occlusion, with the most effective a microfibrillar collagen hemostat in a 33% ethanol solution. Angiostat, a collagen particulate, did not produce rete occlusion, and all pigs injected with it developed adverse effects, including coma and apnea. Tisseel, a tissue sealant, produced partial rete occlusion, but was uniformly difficult to manage through long catheters, and its use was discontinued. Microfibrillar collagen hemostat with ethanol appears to have the greatest potential as an embolic agent in low-flow structures.

In vivo DNA loops in araCBAD: size limits and helical repeat

Formation of a DNA loop by AraC proteins bound at the araI and araO2 sites, whose center-to-center distance is 211 base pairs, is necessary for repression of the araBAD promoter, PBAD, of Escherichia coli. To determine the upper and lower size limits of the loop, we constructed PBAD-reporter gene fusion plasmids with various spacings between araI and araO2 and measured their levels of expression. Spacings larger than about 500 base pairs resulted in elimination of detectable repression. No lower limit to spacing was found, suggesting that AraC protein itself possesses significant flexibility and its bending substantially aids formation of small loops. As the spacing between araI and araO2 varied, the activity of PBAD oscillated with an 11.1-base-pair periodicity, implying that the in vivo helical repeat of this DNA is 11.1 base pairs per turn.

Falx ossification--MR visualization

While falx calcification is rarely demonstrated using magnetic resonance, falx ossification, when seen, is characteristic. On magnetic resonance images, falx ossification exhibits a typical appearance consisting of a central marrow-containing portion with signal intensity similar to fat, surrounded by low signal intensity representing cortical bone. Falx ossification was seen in 0.7% of patients and should not be confused with a falx lipoma, a rare congenital entity.

Oncogene expression detected by in situ hybridization in human primary lung cancer

By means of in situ hybridization using biotinylated oncogene probes and the immunohistochemical reaction of avidin-biotin complex-alkaline phosphatase with substrate, we investigated expression of c-myc oncogene in the formalin-fixed, paraffin-embedded tissue sections from seven patients with squamous cell carcinoma (six cases) and small cell carcinoma (one case) of primary lung origin. The expression of c-myc oncogene was greatly enhanced in all cases studied, with individual and cell-to-cell variation. In contrast, all of the specimens incubated with deoxyribonuclease after the standard pretreatment with ribonuclease T1 were negative for the expression of c-myc oncogene. The in situ hybridization permits estimation of a heterogeneous amplification of c-myc oncogene that may be related to secondary alterations occurring during the progression of the malignant lung tumors.

Effects of otic drops on chinchilla tympanic membrane

Experimental studies have shown that if antibiotic otic drops reach the middle ear cavity they produce severe inflammation. However, the effects of these preparations on the tympanic membrane have not been thoroughly investigated. This study was designed to assess morphological changes in the chinchilla tympanic membrane two to 21 days after a single 0.2-mL application of an antibiotic otic preparation (Cortisporin Otic Suspension) to the middle ear cavity. At two days, the epidermal and the mucosal layers were destroyed. By four days, reepithelialization had occurred and all layers of the tympanic membrane subsequently became markedly hyperplastic. Disruption of the fibrous layer, invasion of keratinizing epidermis to the medial surface, and perforation were observed at three weeks. These findings indicate that tympanic membrane damage is a potentially significant aspect of the ototoxic properties of topical otic preparations.

Superior aspect of the perirenal space: anatomy and pathological correlation

To study the anatomy of the superior aspect of the perirenal space, we analysed 50 computed tomographic (CT) scans with reference to the anatomy of Gerota's fascia, and dissected five cadavers laying special emphasis on the ascent of Gerota's fascia. We also reviewed 10 scans of patients with a large lesion in the right upper abdomen regarding localisation of the lesion. We conclude that Gerota's fascia does not cover the upper portion of the kidney and adrenal gland so that the superior aspect of the perirenal space is open towards the upper abdominal extraperitoneal space. Thus, a large lesion arising from the right adrenal gland or kidney easily invaginates the liver through the bare area mimicking a hepatic lesion, and vice versa. This explains the difficulty in localising a large lesion in the right upper abdomen.

Morphologic effects of glycerol and urea on cochlear tissues of the chinchilla

Glycerol and urea are used as test agents in confirming the diagnosis of endolymphatic hydrops. Although both substances act as osmotic diuretics, recent evidence suggests that they may have differing physiologic effects on the inner ear. This study was designed to compare the morphologic effects of urea and glycerol on cochlear tissues, using the chinchilla as an experimental model. Animals were given subcutaneous injections of glycerol (2 g/kg) or urea (1.2 g/kg) over periods of 3 hours, 4 days, or 1 week. Both agents were found to produce ultrastructural changes, including spiral ligament vacuolization, intracellular alterations of the stria vascularis, and increased numbers of Hensen's bodies in outer hair cells. These alterations appeared indicative of metabolic stress, but not toxicity. The morphologic findings provided no evidence that glycerol and urea affect the inner ear by fundamentally different mechanisms of action.

Detection of hepatitis B virus DNA in human serum by dot hybridization using a biotin-labelled probe

A dot blot hybridization technique utilizing a biotin-labelled recombinant DNA probe was used to examine hepatitis B virus (HBV) DNA in serum. The lowest amount of HBV DNA in serum detectable by the color development of an avidin-biotin alkaline phosphatase complex was 40 picogram per 50 microliter. Validity of this method was confirmed by autoradiography using ³²P-labelled and ³H-labelled HBV DNA probes. HBV DNA was found in 100% (34/34) of the HBsAg-positive and in 73.5% (25/34) of the HBsAg-negative subjects. In contrast, all nine cases showing negativity in HBV DNA were also HBsAg-negative. Correlation of HBe antigen/antibody with HBV DNA was investigated in 19 sera of which HBsAg was negative but anti-HBc-positive. Of 13 sera with anti-HBe 10 (76.9%) cases revealed HBV DNA positivity, while four (66.7%) of six sera without anti-HBe were positive in HBV DNA. In conclusion, serum dot hybridization assay utilizing a biotinylated probe proved useful in the detection of a free form of HBV DNA regardless of the presence of HBsAg and irrespective of HBeAg/anti-HBe status. Moreover, it is emphasized that practical advantages in speed, reproducibility, and safety have made this alternative even more attractive than autoradiography using radioisotope-labelled probes.

Hepatitis B virus DNA detection by in situ hybridization in human hepatocellular carcinoma

The distribution of hepatitis B virus (HBV) DNA in tumor tissue sections from six Korean patients with HBsAg positive hepatocellular carcinoma (HCC) was examined by in situ hybridization using a biotin-labeled recombinant, cloned HBV DNA probe. All patients tested were positive for both HBeAg and anti-HBc in their sera. HBV DNA was distributed abundantly in the cytoplasm and rarely in the nuclei of tumor cells. The validity of the in situ hybridization assay was confirmed by the dot blotting technique using a ³²P-labeled HBV DNA probe obtained by nick translation. In conclusion, it is speculated that integration of HBV DNA into host DNA as well as persistant amplified replication of the HBV DNA within the hepatocytes is linked etiologically to the development of human hepatocellular carcinoma.