Migration of intradural epidermoid matrix: embryologic implications

The migratory behavior of acquired cholesteatoma matrices (those arising from the tympanic membrane) has been described previously. This tissue is derived embryologically from the first branchial groove and represents the only migratory epithelium arising from the branchial groove system. If the matrix from a cerebellopontine angle (CPA) epidermoid tumor exhibits migratory behavior similar to that of acquired cholesteatomas, a first branchial groove site of origin for CPA epidermoids would be supported. Intradural CPA epidermoid cells were grown in alpha-minimum essential medium. The cultures were examined daily, and cell mass migration rates were measured. It was observed that intradural epidermoid tumor matrix harvested from the CPA exhibited migration in vitro. Its migratory properties were indistinguishable from those of acquired cholesteatomas, which are embryologically derived from the first branchial groove. These data support the theory that purely intradural epidermoids are derived from cells of the first branchial groove.

Cervical carcinoma: assessment of parametrial invasion and lymph node metastasis with magnetic resonance imaging

BACKGROUND

Clinical tumor staging of cervical carcinoma has its limitations. The purpose of this study was to stage cervical carcinoma by magnetic resonance imaging (MRI), with an emphasis on the assessment of parametrial invasion and pelvic lymph node metastasis.

METHODS

MRI was performed in 51 women with tissue-proven cervical carcinoma 2 weeks prior to surgery. Images were analyzed for parametrial invasion, pelvic lymph node metastasis and tumor stage. The results were compared with the histopathologic findings after surgery in all patients.

RESULTS

In assessing parametrial invasion, MRI had an accuracy of 94%. In assessing pelvic lymph node metastases, MRI was accurate in 86.3% of cases. In determining stage of disease, MRI had an accuracy of 76.5%. The accuracy of MRI in differentiating localized (< or = stage IIA) from advanced disease (> or = stage IIB) was 94.1%.

CONCLUSIONS

MRI is accurate in the evaluation of parametrial invasion and lymph node metastases and in the differentiation of localized and advanced disease. MRI is beneficial in planning treatment for patients with cervical cancer.

Aberrant cervical carotid artery

Aberrant cervical carotid artery is an uncommon anomaly. Because this anomaly can lie in close proximity to the midline of the posterior part of the pharynx, it poses a significant risk during both major pharyngeal tumor resection and less extensive procedures such as tonsillectomy, adenoidectomy and palatopharyngoplasty. Five cases of aberrant cervical carotid artery were encountered and diagnosed using computerized tomography. In all five cases, the anomalous finding did not correlate with the presenting symptoms. Computerized tomographic images of these cases are provided. A review of the literature and the embryology of the aberrant carotid artery are presented. Awareness of the anomaly by radiologists and surgeons is essential to avoid accidental injury to the vessel during surgery.

Human histo-blood group ABO glycosyltransferase genes: different enhancer structures with different transcriptional activities

The enhancer element of the human histo-blood group ABO glycosyltransferase gene has been demonstrated to be located -3.7 kb upstream from the transcription start site and to be composed of four tandem repeats of a 43-bp unit. Recently we identified three different enhancer structures among the allelic A, B, and O glycosyltransferase genes. The enhancer structure with four 43-bp units is present in the B and O genes, but not in the A gene. The corresponding enhancer region of the A gene contains only one 43-bp unit, and within this unit a nucleotide substitution exists when compared with the consensus sequence. Through transient transfection assays, the transcriptional activity of the A-gene enhancer region was demonstrated to be less than 1% of that of the B-gene enhancer. The difference between the transcriptional activities of the two enhancers became more significant when acting in concert with the ABO-gene's native promoter. The different repeat numbers of the 43-bp unit possessed by the two allelic genes were shown to be the main reason for the vast difference in the transcriptional activities between the A-gene and B-gene enhancers.

Cavernous sinus gas

Gas within the cavernous sinus is an unusual finding. We report three patients who demonstrated gas in the cavernous sinus on computerized tomography (CT). The clinical information of these patients was reviewed for the possible source of the gas and the symptoms induced by the gas. Cavernous sinus gas was seen in two patients with sphenoid sinus fracture and in one patient after intravenous fluid infusion. None of the patients had symptoms referable to the cavernous sinus gas, but one patient had a grave prognosis due to trauma. Identification of cavernous sinus gas on CT and correlation with the clinical information is mandatory for further management.

Synthesis and anti-platelet, anti-inflammatory and anti-allergic activities of methoxyisoflavanquinone and related compounds

In a continuation of our search for novel anti-platelet agents, isoflavone quinone and isoflavanquinone were selected as lead compounds and the synthesis of their methoxy derivatives was carried out. Among them, the 4'- and 7-methoxy derivatives were successfully prepared, whereas the attempt to obtain 3'-methoxy derivatives resulted in their isomers, 3'-methoxyflavone quinone and 3'-methoxyflavanquinone, instead. After screening for their anti-platelet, anti-inflammatory and anti-allergic activities, a preliminary structure-activity relationship was established. Compounds 6c, 7a-c, 8c and 9a-c were found to exhibit significant activities. In particular, compound 7c demonstrated very potent anti-platelet, anti-inflammatory and anti-allergic activities and was then recommended for further pharmacological investigation.

Two new gene cassettes, dfr17 (for trimethoprim resistance) and aadA4 (for spectinomycin/streptomycin resistance), inserted in an Escherichia coli class 1 integron

Two new gene cassettes, dfr17 and aadA4, inserted in a class 1 integron of Escherichia coli EC107, are described here. The dfr17 cassette encodes trimethoprim resistance and has 91% identity with the dfrVII dihydrofolate reductase gene. The aadA4 cassette confers resistance to spectinomycin and streptomycin and shows 94% identity with the aadA3 gene. The integron carrying the dfr17 and aadA4 cassettes was located on a conjugative plasmid, pEC1072.

Transurethral resection of the prostate-related changes in the prostate gland: correlation of MRI and histopathology

PURPOSE

The purpose of this work was to demonstrate signal changes of the prostatic urethra after transurethral resection of the prostate (TURP) on MR images and histopathologic correlation.

METHOD

Sixty-three patients with prostate cancer confirmed by either TURP (Group A, 19 patients) or transrectal biopsy (Group B, 44 patients) were evaluated by endorectal MRI before radical prostatectomies. The MR images of postcurettaged prostatic urethras were correlated with the histopathologic features.

RESULTS

On the T2-weighted images, a thin zone of hypointense signal surrounding the curettaged prostatic urethra was identified in 52.6% (10/19) of Group A patients, imaged soon after (mean 21.1 days) TURP, but was indiscernible in Group B patients and the other Group A patients, imaged later after TURP (mean 49.2 days). This hypointense signal zone histopathologically correlates with a zone of inflammatory tissue reaction surrounding the widened urethra.

CONCLUSION

Inflammatory tissue reaction surrounding curettaged prostatic urethra after TURP accounts for the presence of a low signal zone on T2-weighted images.

Phosphatidylethanol stimulates calcium-dependent cytosolic phospholipase A(2) activity of a macrophage cell line (RAW 264.7)

The synthesis of inflammation mediators produced from arachidonic acid is regulated primarily by the cellular concentration of free arachidonic acid. Since intracellular arachidonic acid is almost totally present as phospholipid esters, the concentration of intracellular arachidonic acid is primarily dependent on the balance between the release of arachidonic acid from membrane phospholipids and the uptake of arachidonic acid into membrane phospholipids. Cytosolic phospholipase A(2) is a calciumdependent enzyme that catalyzes the stimulus-coupled hydrolysis of arachidonic acid from membrane phospholipids. Following exposure of macrophages to various foreign or endogenous stimulants, cytosolic phospholipase A(2) is activated. Treatment with these compounds may also stimulate phospholipase D activity, and, in the presence of ethanol, phospholipase D catalyzes the synthesis of phosphatidylethanol. A cell-free system was used to evaluate the effect of phosphatidylethanol on cytosolic phospholipase A(2) activity. Phosphatidylethanol (0.5 microM) added to 1-stearoyl-2-[(3)H]-arachidonoyl-sn-glycero-3-phosphocholine vesicles stimulated cytosolic phospholipase A(2) activity. However, high concentrations (20-100 microM) of phosphatidylethanol inhibited cytosolic phospholipase A(2) activity. Phosphatidic acid, the normal phospholipase D product, also stimulated cytosolic phospholipase A(2) activity at 0.5 microM, but had an inhibitory effect on cytosolic phospholipase A(2) activity at concentrations of 50 and 100 microM. Ethanol (20-200 mM), the precursor of phosphatidylethanol, added directly to the assay did not alter cytosolic phospholipase A(2) activity. These results suggest that phosphatidylethanol alters the physical properties of the substrate, and at lower concentrations of anionic phospholipids the substrate is more susceptible to hydrolysis. However, at high concentrations, phosphatidylethanol either reverses the alterations in physical properties of the substrate or phosphatidylethanol may be competing as the substrate. Both interactions may result in lower cytosolic phospholipase A(2) activity.

Evaluation of the regenerative effect of a 25% doxycycline-loaded biodegradable membrane for guided tissue regeneration

BACKGROUND

Biodegradable materials have been successfully utilized for guided tissue regeneration (GTR) and local delivery systems (LDS) because they are biocompatible, less cytotoxic, and do not require removal. Several studies have demonstrated that tetracyclines (TCs), when applied topically, stimulated osteogenesis in experimental bone defects. The purpose of this study was to evaluate the regenerative effect of a 25% doxycycline-loaded biodegradable GTR membrane (Doxy-M) in dogs.

METHODS

Doxy-M was made by coating the inner surface of a biodegradable membrane (BD-M) with 25% doxycycline. Five male mongrel dogs with 20 created osseous defects were enrolled. The plain BD-M was used as the control membrane. Either Doxy-M or BD-M was applied in 20 randomly selected defects (10 Doxy-M, 10 BD-M) for 12 weeks with the GTR technique. The histometric analysis was evaluated with the following parameters: defect height (DH), apical extension of junctional epithelium (AEJP), new cementum height (NCH), new bone height (NBH), and new bone area (NBA).

RESULTS

The Doxy-M-treated defects showed more pronounced new bone formation and less crestal bone resorption than the BD-M-treated defects. There were no statistically significant differences between the two groups in DH, AEJP, and NCH. Statistically significantly larger NBH (P <0.05) and NBA (P<0.005) were seen in the Doxy-M-treated defects.

CONCLUSIONS

The results strongly suggest that Doxy-M may have a beneficial effect on osteogenesis to favor periodontal regeneration.

High resolution MRI of adrenal glands in patients with primary aldosteronism

BACKGROUND

We studied the role of high-resolution magnetic resonance imaging (MRI) of the adrenal glands using a surface coil in patients with primary aldosteronism to differentiate aldosterone-producing adenomas (APA) from idiopathic hyperplasia of the adrenal gland (IHA). The data obtained were used to decide on surgical or nonsurgical treatment for patients.

METHODS

High-resolution MRI with SE T1WI, FSE T2WI and paired in- and out-phase images of the adrenal glands of 41 patients with clinically documented primary aldosteronism were collected. The images were reviewed in comparison with other differentiating tests.

RESULTS

Nineteen of the 41 patients were diagnosed with APA on MRI. Surgical and pathologic proof of APA was obtained in 10 cases and solitary macronodular hyperplasia was found in one case. Among these 11 cases, there were no false positive findings on MRI, while correct detectability of high-resolution computerized tomography (CT) was 62.5% (5/8); for adrenal venous sampling, it was 37.5% (3/8); and for NP-59 adrenal scanning, it was 42.9% (3/7). In eight cases with biochemically favored APA and no surgical proof, MRI and CT showed the same lesion detection rate, while there was no concordance with venous sampling, and concordance of only 33.3% (2/6) for adrenal scanning. In the remaining 22 patients without focal lesions on MRI, there was poor concordance among the four test modalities, with frequently conflicting results.

CONCLUSIONS

In patients with definitive results of noninvasive biochemical tests for APA, and positive findings of unilateral, focal adrenal lesion on MRI or CT, unilateral adrenalectomy may be justified without further tedious and invasive examinations. CT should still be the first screening test; however, high-resolution MRI is a useful diagnostic supplement for patients with strong clinical evidence of APA and negative or equivocal findings on CT.

The oxidative metabolism of circulating phagocytes in ankylosing spondylitis: determination by whole blood chemiluminescence

OBJECTIVE

Superoxide anion radicals within the human body are regarded as a major cause of inflammation. However, their role in the pathogenesis of ankylosing spondylitis (AS) has not been well identified. This study aimed at investigating the relation between AS and the oxidative metabolism of phagocytes in whole blood.

METHODS

24 patients with classic AS were examined to determine their clinical status; complete blood count, erythrocyte sedimentation rate (ESR), and C reactive protein (CRP) were determined, and levels of the superoxide anion radicals in the patients with AS and 21 healthy subjects were assessed by the ultraweak chemiluminescence method. Subsequently, the relation between this disease and phagocytes was examined by using N-formyl-methionyl-leucyl-phenylalanine (fMLP) and phorbol-12-myristate-13-acetate (PMA) stimulants.

RESULTS

In clinical assessments, patients with AS had abnormally raised serum CRP (>10 mg/l) and ESR (>15 mm/1st h) levels. In contrast with healthy subjects, patients with AS had significantly increased rates of superoxide anion radical production in their whole blood either in the resting state or with either fMLP or PMA stimulation. In addition, chemiluminescence maximum light intensity was significantly higher in patients with AS than in healthy subjects after fMLP or PMA stimulation.

CONCLUSIONS

Our results suggest that the phagocytes of patients with AS are partly activated in the resting state, and are sensitive to fMLP or PMA stimulation. The priming of phagocytes in the bloodstream is likely to be a causative factor in the onset of AS.

ATM gene deletion in patients with adult acute lymphoblastic leukemia

BACKGROUND

Loss of heterozygosity (LOH) at the ATM gene (mutated in ataxia telangiectasia [AT] patients) and ATM protein deficiency occur in 14% and 34%, respectively, of patients with chronic lymphocytic leukemia (CLL). ATM protein deficiency also is associated with aggressive disease and worse patient survival. Considering the aberrations in the ATM gene in CLL and the high rate of incidence of lymphoid neoplasias in AT patients, the authors investigated its incidence rate and significance in patients with adult acute lymphoblastic leukemia (ALL).

METHODS

Samples from 36 adults with ALL were analyzed for LOH and homozygous deletion (HD) using a panel of three microsatellite markers located at the ATM gene (D11S2179), the MLL gene (D11S1356), and the BCL1 gene (D11S987) loci. These markers are located within the 11q13-q23 locus.

RESULTS

Of the 36 informative cases, 10 (28%) showed deletions (7 LOH and 3 HDs) at the D11S2179 marker. In two patients, the deletions were extended to the MLL gene locus. These deletions were submicroscopic because only 3% (1 of 36) of patients showed abnormalities involving 11q23 using cytogenetic studies. The authors also estimated the levels of ATM protein in 15 ALL patients and 12 healthy volunteers by radioimmunoassay. The ATM protein levels in cases with LOH at the ATM gene were between 15-50% of those from normal bone marrow. In contrast to CLL patients, patients with LOH or HD at the ATM gene locus showed better survival compared with patients without ATM gene deletions (P = 0.003).

CONCLUSIONS

LOH of the ATM gene and protein deficiency are common in adult ALL, are not demonstrated at the cytogenetic level, and are associated with a favorable prognosis. The authors speculate that ATM deficiency may increase the sensitivity of leukemic blasts to the chemotherapy used during induction and after disease remission in patients with adult ALL. The relatively high frequency of deletion of the D11S2179 marker compared with the D11S1356 marker suggests that ATM is the target gene of the deletion at the 11q23 locus, and that such deletions may play a role in the pathogenesis of ALL.

Endovascular embolization of intractable epistaxis

BACKGROUND

We undertook this study to define the role of angiography and endovascular embolization in the treatment of patients with intractable epistaxis.

METHODS

A series of 19 patients with massive intractable epistaxis, all treated with endovascular embolization were reviewed. There were 15 males and four females ranging in age from 18 to 70 years, with a mean age of 38 years. The predisposing factors of intractable epistaxis were head and neck tumors (n = 11), idiopathic symptoms (n = 3), surgical complications (n = 2), arteriovenous malformation of the face (n = 1), thrombocytopenia (n = 1) and trauma (n = 1). Polyvinyl alcohol (PVA) particles and gelfoam plugs were used as embolic agents in 11 patients for devascularization; detachable balloons with N-butyl-2-cyanoacrylate (NBCA) were used in four patients for vascular occlusion; NBCA and/or coils were used in four patients in the carotid and subclavian arteries for obliteration of pseudoaneurysms.

RESULTS

Complete cessation of epistaxis was achieved in all 19 patients immediately after embolization. Seven patients had also undergone surgical tumor removal at two to five days after embolization. Two patients experienced mild to moderate facial pain on the first day after the procedure, but the symptoms later subsided. No significant complication or recurrence was observed in 18 patients. One patient with advanced hypopharyngeal carcinoma died two weeks after embolization due to another episode of massive epistaxis. Clinical follow-up for these patients was 15 days to eight years, with a mean of 41 months.

CONCLUSIONS

Therapeutic endovascular embolization of intractable epistaxis is both efficient and safe. It should be considered as the primary treatment modality in intractable epistaxis.

The pH and anion effects on the heterogeneous photocatalytic degradation of o-methylbenzoic acid in TiO2 aqueous suspension

This investigation used UV light of 365 nm and titanium dioxide in aqueous suspension to study the photocatalytic reaction of o-methylbenzoic acid under the influence of pH values, anion additives and the varieties of titanium dioxide. From experimental results, under the condition of 5 g/l TiO2, pH 3 and light intensity of 2.45 mW/cm2, 0.1 mM of o-methylbenzoic acid could be completely decomposed in 2 h. The reaction was faster with lowering pH, and was found to be apparent first-order following Langmuir-Hinshelwood model. In the presence of anion additives, the inhibitive effect of chloride ions was larger than that of sulfate ions under acidic condition for Degussa brand titanium dioxide, but without influence using Janssen brand. Both brands, however, promoted the mineralization of o-methylbenzoic acid (o-MBA).

Lipopolysaccharide-stimulated nitric oxide production and inhibition of cell proliferation is antagonized by ethanol in a clonal macrophage cell line

Both chronic and acute ethanol exposure have been shown to be cytotoxic and also to disrupt normal cell function or responses in a variety of cell types. Macrophage function has specifically been shown to be disrupted by chronic ethanol exposure by mechanisms that have not been elucidated. It is known that exposure of macrophages to lipopolysaccharide (LPS) from gram-negative bacteria will decrease the number of cells. Since increased exposure to endotoxin is often associated with chronic alcoholism, this may be one mechanism to account for loss of macrophages in alcoholic patients. The loss of macrophages, as a consequence of endotoxin treatment, appears to be linked to cell activation and, in particular, LPS-stimulated synthesis of nitric oxide which has been suggested to cause an increase in apoptosis. Ethanol also increases apoptosis in some cell types but, in general, ethanol inhibits activation of macrophages. Thus, the overall effect on cell numbers and cell proliferation elicited by treating macrophages concomitantly with ethanol and LPS depends on the balance between inhibiting LPS-mediated activation and the actions of ethanol. The interaction between ethanol and LPS was investigated in a macrophage cell line (RAW 264.7 cells) by measuring nitric oxide production and cell proliferation. A 24-h exposure to ethanol (100 mM) decreased [3H]-thymidine incorporation significantly. LPS treatment elicited a concentration-dependent decrease in [3H]-thymidine incorporation at LPS concentrations of 0.1 ng/ml to 1000 ng/ml and stimulated nitric oxide production at concentrations above 1 ng/ml. LPS-stimulated nitric oxide production was inhibited by ethanol (20 to 100 mM) and the nitric oxide synthesis inhibitor, N(G)Nitro-L-arginine methyl L-NAME) ester (100 and 500 microM). However, LPS-inhibited [3H]-thymidine incorporation was not be totally reversed by ethanol- or L-NAME-treatment. A direct correlation between nitric oxide production and inhibition of cell proliferation could not be demonstrated. However, it appears that ethanol and LPS do affect some common mechanism(s) in this cell line.

Effect of verapamil on cholesteatoma migration in vitro

OBJECTIVES

It was previously shown that cholesteatoma migration in vitro is influenced by the calcium concentration of the culture medium. This study was designed to determine whether the calcium channel blocker verapamil affects cholesteatoma migration in vitro.

METHODS

Cholesteatoma cells harvested from patients with chronic ear disease were grown in culture and were exposed to culture medium containing verapamil. The migration rate of the verapamil-exposed cells was compared with control rates.

RESULTS

Verapamil at 300 microgram/L caused marked reduction in the rate of migration compared with control values. The migration rate returned to normal within 48 hours after verapamil was removed from the culture medium. Higher verapamil concentrations (500 microgram/L) caused complete detachment of the epithelial cells from the substrate within 24 hours.

CONCLUSION

Our findings suggest that cholesteatoma migration in vitro is calcium channel dependent and can be reduced with calcium channel blockers such as verapamil.

Fast eigenspace decomposition of correlated images

We present a computationally efficient algorithm for the eigenspace decomposition of correlated images. Our approach is motivated by the fact that for a planar rotation of a two-dimensional (2-D) image, analytical expressions can be given for the eigendecomposition, based on the theory of circulant matrices. These analytical expressions turn out to be good first approximations of the eigendecomposition, even for three-dimensional (3-D) objects rotated about a single axis. In addition, the theory of circulant matrices yields good approximations to the eigendecomposition for images that result when objects are translated and scaled. We use these observations to automatically determine the dimension of the subspace required to represent an image with a guaranteed user-specified accuracy, as well as to quickly compute a basis for the subspace. Examples show that the algorithm performs very well on a number of test cases ranging from images of 3-D objects rotated about a single axis to arbitrary video sequences.

Imaging of invasiveness of pituitary adenomas

The purpose of our study was to examine the tumor size, imaging invasiveness of the pituitary macroadenomas (PMA) and to evaluate the directions of PMA spread. One hundred and thirty-five patients with PMA were examined with MRI and/or CT for pre-operative evaluation. We retrospectively reviewed the CT and MRI to identify tumor size, extension and to evaluate the directions of tumor spread. One hundred and seventeen patients (87%) had suprasellar extension with compression of optic apparatuses, twelve patients (9%) had extension of tumor upward to hypothalamus and third ventricle. Infrasellar extension via the floor of the sella and sphenoid sinus was found in thirty-eight patients (28%), and further downward extension to ethmoid sinus, nasopharynx and/or skull base was depicted in five patients (4%). Twenty-two patients (16%) had lateral invasion to the cavernous sinus and associated cranial nerves. Temporal and frontal extensions were depicted in seven patients (5%) and six patients (4%), respectively. Five patients (4%) had posterior subtentorial extension to posterior fossa. Histologically, only two patients showed microscopic invasive features. There was no correlation between histologic features and imaging invasiveness. The PMA had the potential of multi-directional extension. This experience indicated any type of pituitary adenoma could invade surrounding structures. Suprasellar invasion was the most common direction of pituitary adenoma spread, followed by infrasellar, lateral, anterior and posterior routes.

Aberrant left brachiocephalic vein: CT imaging findings and embryologic correlation

Computed tomography was utilized to evaluate aberrant left brachiocephalic vein (ALBCV), an infrequently discussed congenital vascular anomaly among Chinese people. Associated vascular variation and possible embryonic correlation are discussed. Since 1990, a total of 14 cases of ALBCV have been reported in patients receiving CT scan of chest, and was mainly an incidental diagnosis. One case was confirmed angiographically and two others were confirmed by magnetic resonance imaging. Emphasis was placed on the entry of the azygos vein into the superior vena cava (SVC), the length of the SVC, and the presence of other cardiovascular abnormalities. Of the 14 cases of ALBCV, the level of azygos vein entry was higher than the origin of the SVC in 7 cases: 4 were approximately the same level and 3 were lower. The average length of the SVC was approximately 5. 6 cm shorter than that of the general population, which is approximately 7.0 cm. Three cases had associated vascular anomaly. Most cases of ALBCV had azygos vein drainage level higher than or equal to the origin of the SVC. Right-sided aorta is one of the causes giving rise to the ALBCV during embryonic development. The CT scan remains a definitive diagnostic modality for ALBCV.

Lack of association between deletion polymorphism of the ACE gene and ischemic vascular diseases in a Chinese population in Taiwan

BACKGROUND

The association between deletion/insertion polymorphism of the angiotensin I-converting enzyme (ACE) gene and ischemic vascular diseases (IVDs) is still unclear. This study was designed to evaluate the role of ACE gene polymorphism in the pathogenesis of IVDs in a Chinese population living in Taiwan.

METHODS

A case-control study was carried out to examine the association of the ACE gene genotype and the allele frequency in 400 IVD patients, including 214 patients with ischemic cerebrovascular disease (ICVD) and 186 patients with ischemic heart disease (IHD), compared with 200 control individuals.

RESULTS

Although the patients with ICVD and IHD were found to have higher frequencies of the D/D genotype (22% and 43%) and the D allele (20% and 42%) than the controls (16% and 39%), the statistical differences were not significant, as shown by chi 2 analysis (p > 0.05). Upon further comparison of the frequencies of the D allele among the two sexes and different age subgroups, there was still no significant association.

CONCLUSIONS

Deletion polymorphism of the ACE gene was not associated with IVD in a Chinese population in Taiwan. The unique or synergistic effect of other genes that might contribute to the pathogenesis of IVDs needs further investigation.

Giant cell reparative granuloma: a case report

Giant cell reparative granuloma (GCRG) is an infrequent benign lesion with undetermined etiopathogenesis affecting the maxillary and mandibular bone and, rarely, the skull. It is also extremely rare in the sphenoid bone. GCRG is usually diagnosed by histologic examination of bone lesions. We report a case of GCRG originating from the sphenoid bone. Computerized tomography revealed an expansile lesion with thinning or destruction of the cortical bone. The lesion itself was slightly hyperdense with good but inhomogeneous contrast enhancement. Reported magnetic resonance image findings showed hyperintensity on both T1-weighted and T2-weighted images and variable contrast enhancement. Plain skull radiographs usually reveal a lytic lesion within the bone.

Identification of five spinocerebellar ataxia type 2 pedigrees in patients with autosomal dominant cerebellar ataxia in Taiwan

OBJECTIVES

The autosomal dominant cerebellar ataxias (ADCAs) are a group of genetically diverse neurological conditions linked by progressive deterioration in balance and coordination. Spinocerebellar Ataxia Type 2 (SCA2) is one of the ADCAs and also belongs to a special group caused by the expansion of an unstable CAG repeat encoding a polyglutamine tract. We aimed to investigate the frequency of SCA2 mutation in the ataxia patients referred to the clinic.

MATERIALS AND METHODS

We screened 58 families with inherent cerebellar ataxia and 57 normal individuals by the use of radioactive genomic polymerase chain reaction (PCR) method. A simple non-radioactive PCR for rapid detection of the expanded SCA2 alleles via agarose gel electrophoresis was also employed.

RESULTS

Eight SCA2 affected patients and 1 at-risk individual in 5 unrelated SCA2 families were identified. The CAG repeats of normal alleles in the sample studied range in size from 16 to 30 repeat units, while those of SCA2 chromosomes are expanded to 34 to 49 repeat units. Our results also showed that unlike SCA 1 and SCA3/MJD, the size distribution of the normal alleles showed few polymorphisms, with the 22 repeat allele accounting for 90.1%. Homozygosity in normal individuals was 80.2%. No overlap in ataxin-2 allele size between normal and expanded chromosomes was observed.

CONCLUSION

This is the first report of the SCA2 gene distributions in the population of Taiwan. The SCA2 mutation accounts for 8.6% of ADCA type I families referred to us, intermediate between SCA1(1.7%) and SCA3/MJD (24%) of the ADCA type I families in our collection.

Magnetic resonance imaging of unilateral olivary hypertrophy due to pontine tegmental hemorrhage: a case report

Olivary hypertrophy (OH) is not a primary lesion but, rather, develops as a lesion of the Guillain-Morraret triangle, which is composed of the contralateral dentate nucleus, the ipsilateral red nucleus and the ipsilateral inferior olivary nucleus. OH is usually accompanied by palatal myoclonus or other involuntary movements such as extremity myorhythmia. One case of unilateral OH following ipsilateral pontine tegmental hemorrhage is presented. Magnetic resonance imaging (MRI) showed high signal intensity in the inferior olivary nuclei on T2- and proton-density-weighted images. Enlargement of the inferior olivary nuclei was also noted. MRI may currently be the only procedure capable of confirming the diagnosis.

Intracranial pathology: comparison of intraoperative ultrasonography with computerized tomography and magnetic resonance imaging

BACKGROUND

High-resolution, real time, intraoperative ultrasonography (IOUS) has been used in a number of cases in our neurosurgical department to identify, localize and characterize intracranial abnormalities. We compare the images of IOUS with those of computerized tomography (CT) and magnetic resonance imaging (MRI) in order to enhance our experience and confidence.

METHODS

IOUS images were compared with preoperative CT scans and/or MRIs in 30 intracranial masses. Tumor size and margin, echogenicity and edema were the features compared.

RESULTS

The images of IOUS, CT and MRI correlated closely except for images of primary gliomas. IOUS was more effective than CT and MRI in delineating the extent of a glioma, determining whether a lesion was cystic, with or without septation, or solid and in guiding surgical procedures. The contrast enhancement available with CT and MRI could not be demonstrated with IOUS.

CONCLUSIONS

IOUS provides exquisite detail of intracranial pathology as well as, or even better than, CT and MRI. Its application should be emphasized to minimize damage of normal brain tissue and increase the completeness of tumor resection.

Clinical impact of upper gastrointestinal tract injuries in glyphosate-surfactant oral intoxication

Fifty patients with glyphosate-surfactant oral ingestion were studied with upper gastrointestinal (UGI) endoscopic grading using Zargar's modified grading system for mucosal corrosive injury. Esophageal injury was seen in 68% of the patients, gastric injury in 72%, and duodenal injury in 16%. There were no grade 3 injuries. The upper gastrointestinal tract injuries caused by glyphosate-surfactant were minor in comparison with those by other strong acids. The WBC count, amount of glyphosate-surfactant ingested, length of hospital stay and the occurrence of serious complications increased markedly in the group which had grade 2 esophageal injuries. Thus, the severity of the esophageal injuries may be a prognostic factor for the patient with glyphosate-surfactant ingestion. The UGI endoscopy may be indicated for grading esophageal injury in patients who have ingested glyphosate-surfactant in amounts greater than 100 ml. Physicians should pay more attention to the patients with grade 2 or 3 esophageal injuries to prevent serious complications and to provide aggressive supportive care.

Alternative and effective treatment of shoulder ganglion cyst: ultrasonographically guided aspiration

The therapeutic effect of ultrasonographically guided aspiration of a ganglion cyst of the shoulder is evaluated. Fifteen patients (nine male, six female) with chronic shoulder pain were enrolled in this study. Each patient was referred to rule out rotator cuff lesion. The ultrasonographic examination showed an anechoic cystic lesion in the shoulder region in every patient and abnormality of the rotator cuff in only four patients. Under ultrasonographic guidance, an 18 gauge needle was inserted into the cyst to aspirate the fluid. Initial sonographic imaging showed the cyst, which appeared as a localized fluid accumulation and was located between the deltoid muscle and the subscapularis tendon in seven patients, between the deltoid muscle and the biceps tendon in one patient, below the coracoacromial ligament in five patients, and over suprascapular notch area in one patient. The ganglion cysts ranged in size from 3.5 to 30 mm. The amount of aspirated fluid in each cyst varied from 0.4 to 12 ml (mean, 2.6 ml +/- 3.1) with a clear or light yellowish color and a jelly-like appearance. No major complications occurred during or after this procedure. The symptom (pain) was improved after sonographically guided aspiration in each patient. Follow-up study showed complete relief of pain in four patients, marked improvement in nine patients, and mild improvement but still persistent shoulder pain in two patients. Duration of follow-up study ranged from 2 to 24 months (mean, 6.4 months +/- 6.9). The success rate for sonographically guided aspiration was 86% on the basis of marked symptom improvement or relief. Ultrasonographically guided aspiration of shoulder ganglion cysts is an effective procedure in the management of shoulder pain caused by ganglion cysts.

Peptide antagonists of the human estrogen receptor

Estrogen receptor alpha transcriptional activity is regulated by distinct conformational states that are the result of ligand binding. Phage display was used to identify peptides that interact specifically with either estradiol- or tamoxifen-activated estrogen receptor alpha. When these peptides were coexpressed with estrogen receptor alpha in cells, they functioned as ligand-specific antagonists, indicating that estradiol-agonist and tamoxifen-partial agonist activities do not occur by the same mechanism. The ability to regulate estrogen receptor alpha transcriptional activity by targeting sites outside of the ligand-binding pocket has implications for the development of estrogen receptor alpha antagonists for the treatment of tamoxifen-refractory breast cancers.

Simplified Description of Adsorption Breakthrough Curves of 1,1-Dichloro-1-fluoroethane (HCFC-141b) on Activated Carbon with Temperature Effect

Recovery of HCFC-141b, used as a major alternative solvent and foam-blowing agent for CFCs in industrial applications, has received great attention due to its gradual phase out. This paper describes an investigation of the adsorption breakthrough of HCFC-141b vapor on a commercial activated carbon. A simple theoretical model developed by Yoon and Nelson was applied to investigate the breakthrough behavior of HCFC-141b on an activated carbon column. The values of parameters k' (a rate constant) and tau (the time required for 50% adsorbate breakthrough) in the Yoon and Nelson model were determined at four different concentration levels (i.e., 399, 734, 1139, and 1954 ppmv) and five temperature ranges (i.e., 283, 293, 298, 303, and 313 K), respectively. These values were used to calculate the entire (0-100%) breakthrough curve (plot of percentage breakthrough versus time) regarding the adsorption of HCFC-141b on activated carbon columns. It was found that the calculated theoretical breakthrough curves are in high agreement with the corresponding experimental data. Also, the rate constant k' can be reasonably represented by the empirical Arrhenius equation. The results obtained are applicable for the scale-up design of adsorption columns in the HCFC adsorption on activated carbon adsorbent. Copyright 1999 Academic Press.

Characterization of the dual start motif of a class II holin gene

Holins are small membrane proteins that, at a genetically programmed time in a bacteriophage infective cycle, allow bacteriolytic enzymes, or endolysins, to escape to the periplasm and to attack the cell wall. Most holins fall into two sequence classes, I and II, based on the number of potential transmembrane domains (three for class I and two for class II). The prototype class I holin gene, S lambda, has a dual start motif and encodes not only the effector holin, Slambda105, but also an inhibitor, Slambda107, with a Met-Lys ...extension at the terminus. The prototype class II holin gene of phage 21, S 21, begins with the motif Met-Lys-Ser-Met ..., and a potential RNA secondary structure overlaps the Shine-Dalgarno sequence. Here, we demonstrate that (i) two protein products are elaborated from S 21, S2171 and S2168; (ii) the shorter product is required for lysis; (iii) the longer product, S2171, inhibits S 21 function; and (iv) the Lys-2 residue is important for the inhibitor function. Moreover, the RNA stem-loop structure is involved in the downregulation of S2171 synthesis. However, our results suggest that, in S 21, different segments of the single consensus Shine-Dalgarno sequence serve the two translational starts. These results show that the dual start motifs of class II holin genes are functionally homologous to those of class I holin genes.

Fat-suppressed three-dimensional fast spoiled gradient-recalled echo imaging: a modified FS 3D SPGR technique for assessment of patellofemoral joint chondromalacia

Fast fat-suppressed (FS) three-dimensional (3D) spoiled gradient-recalled echo (SPGR) imaging of 64 articular cartilage regions in 16 patellofemoral joints was evaluated to assess its feasibility in diagnosing patellofemoral chondromalacia. It demonstrated good correlation with arthroscopic reports and took about half of the examination time that FS 3D SPGR did. This modified, faster technique has the potential to diagnose patellofemoral chondromalacia with shorter examination time than FS 3D SPGR did.

The C-terminal sequence of the lambda holin constitutes a cytoplasmic regulatory domain

The C-terminal domains of holins are highly hydrophilic and contain clusters of consecutive basic and acidic residues, with the overall net charge predicted to be positive. The C-terminal domain of lambda S was found to be cytoplasmic, as defined by protease accessibility in spheroplasts and inverted membrane vesicles. C-terminal nonsense mutations were constructed in S and found to be lysis proficient, as long as at least one basic residue is retained at the C terminus. In general, the normal intrinsic scheduling of S function is deranged, resulting in early lysis. However, the capacity of each truncated lytic allele for inhibition by the S107 inhibitor product of S is retained. The K97am allele, when incorporated into the phage context, confers a plaque-forming defect because its early lysis significantly reduces the burst size. Finally, a C-terminal frameshift mutation was isolated as a suppressor of the even more severe early lysis defect of the mutant SA52G, which causes lysis at or before the time when the first phage particle is assembled in the cell. This mutation scrambles the C-terminal sequence of S, resulting in a predicted net charge increase of +4, and retards lysis by about 30 min, thus permitting a viable quantity of progeny to accumulate. Thus, the C-terminal domain is not involved in the formation of the lethal membrane lesion nor in the "dual-start" regulation conserved in lambdoid holins. Instead, the C-terminal sequence defines a cytoplasmic regulatory domain which affects the timing of lysis. Comparison of the C-terminal sequences of within holin families suggests that these domains have little or no structure but act as reservoirs of charged residues that interact with the membrane to effect proper lysis timing.

Evaluation of ocular arterial changes in glaucoma with color Doppler ultrasonography

The purpose of this study was to evaluate hemodynamic changes of the retrobulbar vasculature caused by different intraocular pressures with color Doppler ultrasonography. Fifty normal eyes in 25 patients, 13 patients with normal tension glaucoma, and 19 patients with acute glaucoma and increased intraocular pressure (greater than 30 mm Hg) were enrolled in this study. In 15 of 19 patients with acute glaucoma patients, follow-up color Doppler ultrasonography was also undertaken after laser peripheral iridectomy when the intraocular pressure had returned to normal. The peak systolic velocity, end diastolic velocity, resistive index, time average maximum velocity, and pulsatility index were compared in different vessels, including the central retinal artery, lateral posterior ciliary artery, medial posterior ciliary artery, and ophthalmic artery in each orbit. The peak systolic velocity, end diastolic velocity, and time average maximum velocity of the central retinal artery were significantly lower (P<0.01) in acute glaucoma patients than in the control group. The resistive index and pulsatility index of the central retinal artery were significantly higher (P<0.01) in acute glaucoma patients than in the control group. The end diastolic velocity of the lateral and medial posterior ciliary arteries was significantly lower in patients with acute glaucoma than in the control group, and the resistive index and pulsatility index of both of these arteries were significantly higher (P<0.001) in patients with acute glaucoma than in the control group. However, no statistical significantly differences were found in the peak systolic velocity or time average maximum velocity in either of the posterior ciliary arteries; similarly, no statistically significant differences were noted in any of the parameters in the ophthalmic artery between the control group and the group with acute glaucoma. The pulsatility index of the central retinal artery and of the lateral and medial posterior ciliary arteries was significantly lower (P<0.01) in acute glaucoma patients after laser therapy than in acute glaucoma patients before laser therapy. The resistive index of both posterior ciliary arteries was also significantly lower (P<0.004) in acute glaucoma patients after laser therapy than before laser therapy. All parameters for all vessels examined among the normal subjects, the patients with normal tension glaucoma, and the patients with acute glaucoma after laser therapy when the intraocular pressure had returned to normal showed no statistically significant differences. Color Doppler ultrasonography is a good modality for both imaging and studying the hemodynamics of the perioptic nerve vessels.

Vascular lesion of the masseter presenting with phlebolith

When evaluating an intramuscular soft tissue mass, a large differential diagnosis including both benign and malignant lesions must be considered. Because the treatment of these masses can range from simple observation to radical surgical excision, a minimally invasive but accurate method of diagnosis is desired. The workup should include radiographic imaging. MRI is the modality of choice for differentiating soft tissue lesions, although CT may be helpful in identifying calcifications such as a phlebolith. Although usually unnecessary, a sialogram can verify that a calcification lies within or outside the salivary ductal system. In most cases a biopsy specimen is required to confirm the diagnosis. However, if the imaging studies show characteristics consistent with a vascular soft tissue mass, the finding of a phlebolith is pathognomonic for a benign vascular lesion. If such a lesion is not causing significant cosmetic or functional disability, it can be observed without the need for invasive biopsy or treatment.

Estrogen receptor (ER) modulators each induce distinct conformational changes in ER alpha and ER beta

Estrogen receptor (ER) modulators produce distinct tissue-specific biological effects, but within the confines of the established models of ER action it is difficult to understand why. Previous studies have suggested that there might be a relationship between ER structure and activity. Different ER modulators may induce conformational changes in the receptor that result in a specific biological activity. To investigate the possibility of modulator-specific conformational changes, we have applied affinity selection of peptides to identify binding surfaces that are exposed on the apo-ERs alpha and beta and on each receptor complexed with estradiol or 4-OH tamoxifen. These peptides are sensitive probes of receptor conformation. We show here that ER ligands, known to produce distinct biological effects, induce distinct conformational changes in the receptors, providing a strong correlation between ER conformation and biological activity. Furthermore, the ability of some of the peptides to discriminate between different ER alpha and ER beta ligand complexes suggests that the biological effects of ER agonists and antagonists acting through these receptors are likely to be different.

Pancreatic adenocarcinoma presenting as sinistral portal hypertension: an unusual presentation of pancreatic cancer

A rare syndrome, sinistral (left-sided) portal hypertension resulting from splenic vein thrombosis secondary to pancreatic adenocarcinoma of the tail is presented here. Pancreatic cancer is notorious for presenting with vague and nonspecific symptoms, including but not exclusively weight loss, abdominal pain, and anorexia with or without jaundice. However, physicians should be aware that in the presence of splenic vein thrombosis, this finding alone puts pancreatic cancer high on the differential diagnosis.

Singlet oxygen is the major species participating in the induction of DNA strand breakage and 8-hydroxydeoxyguanosine adduct by lead acetate

To investigate DNA damage induced by Pb2+ and its prevention by scavengers, we determined DNA strand breakage and the formation of 8-hydroxydeoxyguanosine (8-OHdG) in DNA using plasmid relaxation assay and HPLC with electrochemical detection, respectively. Lead acetate induced DNA strand breakage in 10 mM of Hepes buffer, pH 6.8, in a time- and dose-dependent manner. Compared with lead, zinc acetate did not significantly induce DNA breakage. The singlet oxygen scavengers NaN3 and 2,2,6,6-tetramethyl-4-piperidone (TEMP) inhibited lead-induced DNA breakage more efficiently than the hydroxyl radical scavengers mannitol and DMPO. Deuterium oxide (D2O), a singlet oxygen enhancer, potentiated lead-induced DNA breakage. At low ratios to Pb2+, NADPH, glutathione, and 2-mercaptoethanol enhanced lead-induced DNA breakage, whereas high ratios of these agents protected it. Catalase and superoxide dismutase (SOD) did not protect DNA breaks induced by Pb2+. Lead-induced DNA breakage was markedly enhanced by H2O2, and this induction was inhibited by NaN3, TEMP, EDTA, catalase, BSA, and glutathione. In contrast, mannitol and SOD potentiated Pb2+/H2O2-induced DNA breaks. The results indicate that singlet oxygen, lead, and H2O2 are all involved in the reaction system, whereas hydroxyl radical and superoxide did not. Lead could cause a small amount of 8-OHdG formation in calf thymus DNA and dose-dependently induced the formation of this adduct in the presence of H2O2. Singlet oxygen scavengers were more effective than hydroxyl radical scavengers in protection from lead/H2O2-induced 8-OHdG adducts. Taken together, these results suggest that lead may induce DNA damage through a Fenton-like reaction and that singlet oxygen is the principal species involved.

Management of facial nerve injury due to temporal bone trauma

OBJECTIVE

This article provides an overview of relevant data regarding the management of facial nerve injury due to temporal bone trauma.

DATA SOURCES

Sources used were relevant English language clinical and basic science publications.

STUDY SELECTION

A Medline search dating back to 1966 for articles concerning temporal bone trauma and facial nerve injury including both human and animal data was performed. Articles were included if they contained relevant data or were significant reviews on the subject. A retrograde bibliography search was then conducted to acquire any articles that may have been missed by the computerized search, including those papers published prior to 1966.

DATA EXTRACTION

The data from each paper were reviewed individually.

DATA SYNTHESIS

The data were not amenable to formal meta-analysis or valid data summarization.

CONCLUSIONS

Patients who should not require surgical intervention include those who have: documented normal facial nerve function after injury regardless of progression, presentation with incomplete facial nerve paralysis with no progression to complete paralysis, and degeneration <95% on ENoG. The remaining patients presumably have a poorer prognosis for return of facial nerve function although it remains unclear exactly how poor the return of function will be. Decompression surgery likely has a beneficial effect if performed within 14 days of injury, so those patients with expected poor natural outcomes may be offered this intervention. Late decompression surgery is not recommended. Late exploratory surgery is recommended only in those patients who do not experience adequate recovery of facial nerve function and likely require nerve repair. Despite the availability of a relatively large volume of published data, there remain many unanswered questions.

Arachnoid granulations--computerized tomography and magnetic resonance imaging features: a case report

A 71-year-old woman had arachnoid granulations found in the straight and transverse sinuses on computerized tomography (CT) and magnetic resonance imaging (MRI). The arachnoid granulations appeared as low-density masses on CT. They gave low signals on T1-weighted MR images and high signals on T2-weighted images. Arachnoid granulations are usually of no clinical significance. They have characteristic CT and MRI manifestations and should not be mistaken for sinus thrombosis or intrasinus tumors.

Cubital tunnel syndrome: diagnosis by high-resolution ultrasonography

The purpose of this study was to evaluate the morphologic changes in the ulnar nerve in cubital tunnel syndrome with high-resolution ultrasonography. The mean values of the short axis (cm) x long axis (cm) at the arm, epicondyle, and forearm levels were 0.057 +/- 0.01, 0.068 +/- 0.019, and 0.062 +/- 0.01 in control group; 0.069 +/- 0.04, 0.139 +/- 0.06, and 0.066 +/- 0.023 in the symptomatic side in patients with cubital tunnel syndrome; and 0.063 +/- 0.029, 0.068 +/- 0.029, and 0.057 +/- 0.012 in the normal side in patients with cubital tunnel syndrome. No significant difference was found in the area (short axis x long axis) of the ulnar nerve at the arm, epicondyle and forearm levels between the left and right ulnar nerve in the control group and between the control group and the normal side in symptomatic patients. However, the mean value of the area of the ulnar nerve at the epicondyle level in symptomatic patients was significantly larger than that of the control group and that of the contralateral side in patients, and the P value was less than 0.001. High resolution ultrasonography can detect morphologic changes in the ulnar nerve accurately, and it could therefore be useful as a screening and even follow-up modality in patients with cubital tunnel syndrome.

Studies on segmented polyetherurethane for biomedical application: effects of composition and hard-segment content on biocompatibility

Segmented polyetherurethane (SPEU) materials based on polytetramethylene oxide (PTMO, Mw 1000 and 2000) with various hard-segment contents were synthesized and their biocompatibilities studied via different tests. The static contact angle data reveal that the higher hard-segment-content SPEU material possesses a lower contact angle, implying that the surface of the higher hard-segment-content SPEU is more hydrophilic than its low hard-segment-content SPEU counterpart. The catalyst- and additive-free PTMO-based SPEU materials in this study possess neither a hemolytic nor a cytotoxic response that could be considered non toxic for biomedical applications. By using L-929 cell lines, a cell-seeding test indicated that the higher hard-segment-content SPEU material possesses quicker cell attachment and proliferation behaviors. In vitro platelet adhesion tests indicated that the lower hard-segment-content SPEU possesses less platelet adhesion than the high hard-segment-content SPEU material. Both ex vivo canine artery-artery (A-A) and arterio-venous (A-V) shunting tests revealed that the extent of platelet adhesion reaction is less for lower hard-segment content SPEU. In addition, the blood compatibility of SPEU material synthesized from PTMO 1000 excels over PTMO 2000 SPEU material by near the same levels as the hard-segment-content SPEU.

Giant ossified cavernous hemangioma of an extremity associated with an equinovarus deformity

A 39-year-old woman suffered from swelling and tenderness of the right leg for 31 years. Imaging studies showed a large soft tissue lesion on the right side extending from the proximal portion of the thigh to the ankle. She underwent several operations due to the leg mass and associated equinovarus deformity of the right ankle. The pathologic findings were those of an ossified cavernous hemangioma. This appears to be one of the largest hemangiomas to be reported. It revealed the three types of calcification characteristic of hemangiomas. Equinovarus deformity of the ankle caused by contracture of the calf in this case was probably related to repeated bleeding.

Triangular fibrocartilage perforations with bilateral negative ulnar variant wrists: a case report

Triangular fibrocartilage (TFC) constitutes the major part in the triangular fibrocartilage complex, which stabilizes the distal radioulnar joint and functions as a cushion for axial compression forces. Tears in the TFC are often encountered with positive ulnar variance and regarded as part of a degenerative process of the ulnocarpal joint. They are occasionally seen as the result of trauma and are less likely to be found in a young population, especially in those who are in the first two decades of life, without causative traumatic injury. We report the case of a 12-year-old boy with bilateral negative ulnar variances with incidental findings of TFC tears in both wrists. This is a rare case, as he had no history of a traumatic event.

Lipoblastomatosis of the shoulder: unusual MR appearance

Lipoblastomatosis is a rare benign lipomatous tumour of childhood and infancy, classically showing high signal identical to fat on T1 weighted images. A case of histologically proven lipoblastomatosis in an infant is presented, in which MRI showed low signal on T1 weighted images identical to that of muscle instead of high signal. This appearance has not been previously reported.

Aromatic hydrocarbon receptor polymorphism: development of new methods to correlate genotype with phenotype

Differential CYP1A1 inducibility, reflecting variations in aromatic hydrocarbon receptor (AHR) affinity among inbred mouse strains, is an important determinant of environmental toxicity. We took advantage of the Ahr polymorphism in C57BL/6 and DBA/2 mice to develop an oligonucleotide-hybridization screening approach for the rapid identification of DNA sequence differences between Ahr alleles. Oligonucleotides containing single-base changes at polymorphic sites were immobilized on a solid support and hybridized with C57BL/6 or DBA/2 AHR cDNA radiolabeled probes. The observed hybridization patterns demonstrate that this approach can be used to detect nucleotide differences in the Ahr coding region with very high accuracy. In parallel experiments, we used a yeast two-hybrid system to assess phenotypic differences in AHR function. AHR activation, as measured by beta-galactosidase reporter activity in Saccharomyces cerevisiae strain SFY526, was determined following treatment with varying doses of the AHR ligand beta-naphthoflavone (BNF). We found that the C57BL/6 AHR has about a 15-fold higher affinity for BNF than the DBA/2 AHR, in much better agreement with results reported for whole-animal studies than the values observed by in vitro ligand-binding assays. Using C57BL/6 and DBA/2 AHR chimeric proteins, we also confirmed the previously reported observation that an A375V change is principally responsible for the high- to low-affinity AHR phenotype. There has been no straightforward method to reliably and reproducibly phenotype large numbers of humans for CYP1A1 inducibility or AHR affinity. Screening human AHR cDNAs by oligonucleotide-hybridization and yeast two-hybrid methodologies will be invaluable for the rapid and unequivocal determination of changes in DNA sequence and receptor-ligand affinities associated with human AHR polymorphisms.