MR imaging evaluation of bone marrow signal change in post-irradiation patients with nasopharyngeal carcinoma

BACKGROUND

The normal distribution of red and yellow marrow can be altered by therapeutic irradiation, which causes a well-documented sequence of bone marrow changes. This study measured the T1 signal intensity of the clivus and cervical vertebral bodies of NPC patients who had received a complete course of radiation therapy.

METHODS

There were 3 categories of patients: Group I: NPC patients who had radiation myelitis; 14 persons which a total 20 times of MRI. Group II: NPC patients, without radiation myelitis; 6 patients, which a total 6 times of MRI. Group III (control group): patients who received MRI of the cervical spine because of cervical spondylosis or HIVD, were total of 45 patients. In the sagittal section of T1WI, the signal intensity of the bone marrow of clivus and C2 to T1 vertebral bodies was measured.

RESULTS

1). There were homogeneous increases of signal intensity of the bone marrow of clivus and C2 to T1 in Groups I and II. 2). There was no statistical difference between Groups I and II. 3). The increased signal intensity of bone marrow after radiation showed no difference in short and long duration between radiation therapy and MR examinations, indicating that bone marrow signal intensities were increased in NPC patients whether or not they had radiation myelitis.

CONCLUSIONS

Signal change in bone marrow may have occurred soon after radiation therapy, and may have persisted for several years. The radiation myelitis always involved the low medulla oblongata to C5 level; however, the bone marrow signal change always extended downward to the T1 level, so bone marrow is more sensitive than the spinal cord and is prone to be affected by irradiation.

Use of HPV 1 capsids produced by recombinant vaccinia viruses in an ELISA to detect serum antibodies in people with foot warts

A sandwich ELISA was developed to detect HPV antibodies using HPV 1 capsids that were purified from recombinant vaccinia virus-infected cells and a monoclonal antibody to the HPV 1 L1 protein. Sera from 91 college-aged women who had been previously screened for HPV 1 antibodies by immune precipitation of capsid proteins were tested by ELISA. A cutoff point was established independently of other criteria based on the assumption that the ELISA values came from a mixture of two Normal distributions representing seropositive and seronegative individuals. It was found that the data fit this model best when the natural log of the ELISA (+0.5 to make all of the values positive) was used. Positive sera were shown to react with a conformational epitope(s) on the L1 protein. In the population reporting foot warts, 16 of 18 (89%) had ELISA values above the cutoff. This compared to 38 of 73 (53%) positives in the population reporting no history of foot warts. The odds ratio for the association of the ELISA reactivity with foot warts was 7.23 (95% CI 1.53, 69.4; P < 0.01). There was no significant association between the ELISA reactivity and wart infections reported at other sites. The average of the log ELISA values for individuals never reporting foot warts was -0.223 (SD 0.468), whereas the average value for individuals reporting foot warts within 10 years was 0.191 (SD 0.450) (P = 0.001). There was a negative correlation between the magnitude of ELISA reactivity and the time elapsed since the last appearance of foot warts. This apparent loss of seroreactivity over time may indicate that HPV 1 is usually eliminated from the host after infection or that inadequate levels of HPV 1 capsid antigen are produced during latent foot warts to maintain antibody levels.

Sertoli cell-conditioned medium affects nucleoside utilization in vitro

Rat Sertoli cell-conditioned medium (SCCM) or low molecular weight filtrate of SCCM (< 1,000 Da molecular weight) inhibited the uptake of [3H]thymidine into cells in culture; [3H]thymidine is incorporated into DNA by means of a salvage pathway. The incorporation of radioactivity into DNA from [14C]N5,N10-methylene-tetrahydrofolate, required for the thymidylate synthetase reaction, was not inhibited by SCCM and reflected the increase in cell number. SCCM specifically inhibited the incorporation of pyrimidines ([3H]uracil, [3H]thymidine) with no effect on the transport or incorporation of [3H]adenosine. Inhibition of thymidine uptake by SCCM could have occurred by a direct competition, i.e., the secretion of thymidine into the medium by the Sertoli cells, or by an indirect mechanism that would result in an inhibition of transport. The activity was partially purified by membrane ultrafiltration, ion exchange chromatography, and sequential extraction. Addition of SCCM filtrate (< 1,000 Da molecular weight) to growth-arrested cells cultured in the presence of inhibitors of dihydrofolate reductase resulted in cell proliferation, suggesting that the factor is involved in thymidine biosynthesis. This activity may play a role in the regulation of nucleoside biosynthesis and/or utilization in the testis.

Somatic embryogenesis and plant regeneration in Quercus acutissima

Immature embryos of Quercus acutissima were collected weekly beginning 5 weeks post-fertilization and cultured on modified MS(Murashige and Skoog) medium containing 1,000 mg/l glutamine and 5 mM proline with different combinations of IBA(0.5-10.0 mg/l) and BA(0 or 1.0 mg/l) in light. The highest percentage of embryogenic cultures occurred on the medium containing 0.5 mg/l IBA or 1.0 mg/l BA and 0.5 mg/l IBA. Four weeks after initiation, the embryogenic cultures were transferred to MS medium without plant growth regulators and cultured for 4 weeks. The somatic embryos were then transferred to germination medium. The best germination results were achieved from WPM(Woody Plant Medium) containing 0.1 mg/l BA. Plantlets from somatic embryos were incubated on WPM supplemented with 0.2 mg/l BA for 4 weeks and plantlets with well developed shoots and roots were transplanted to perlite and peat moss(1∶1, v/v) mixtures and placed in a culture room. After being hardened off for 8 weeks, they were transferred outdoors where they grew.

[Nine cases of strongyloidiasis in Korea]

Nine cases of human infection with Strongyloides stercoralis are reported among patients admitted to the Seoul Paik and Sang-Kye Paik Hospitals, Inje University, from April 1990 to January 1992. The patients, 7 males and 2 females aged between 50 and 70, either had the history of long term use of steroids for management of arthritis, or were complicated with other chronic diseases such as hypertension, liver diseases, psychotic disorders, and gastrointestinal problems. All of the nine patients revealed rhabditoid larvae of S. stercoralis in fecal examination. A 57-year-old woman who complained of arthritis and abdominal discomfort, was treated with albendazole and mebendazole, and on the 4th and 5th treatment day 220 parasitic adult females were collected from the diarrheal stool. The patient had a long history of administration of steroids for treatment of arthritis, and seems to have suffered from hyperinfection syndrome due to autoinfection with S. stercoralis. This is the 3rd report on the recovery of parasitic adult females of S. stercoralis in Korea.

[Second report on intestinal parasites among the patients of Seoul Paik Hospital (1984-1992)]

The results of fecal examination for helminth eggs and protozoan cysts in Seoul Paik Hospital during 1984-1992 are reported. Fecal specimens of a total of 52,552 out- or inpatients were examined by formalin-ether sedimentation and/or direct smear method. The overall egg positive rate of helminths was 6.5% and the cyst positive rate of protozoa 2.5%. The egg positive rate (number of positive cases) for each species of helminth was; Clonorchis sinensis 3.2% (1,667), Trichuris trichiura 2.0% (1,089), Metagonimus yokogawai 1.2% (613), Ascaris lumbricoides 0.2% (100), Trichostrongylus orientalis 0.1% (34), Taenia spp. 0.05% (28), Hymenolepis nana 0.03% (18), hookworms 0.03% (17), Paragonimus westermani 0.02% (12), Echinostoma spp. 0.03% (12), Enterobius vermicularis 0.02% (10), Strongyloides stercoralis (larvae) 0.01% (6), and Diphyllobothrium latum 0.004% (2). The cyst positive rate (number of positive cases) for each protozoan was; Entamoeba coli 1.1% (588), Endolimax nana 0.8% (402), Giardia lamblia 0.3% (173), Entamoeba histolytica 0.3% (164), and Trichomonas hominis (trophozoites) 0.004% (2). Viewing from the data of 9 years, it was evident that the prevalence of soil-transmitted helminths such as A. lumbricoides and T. trichiura has been decreasing remarkably, while that of snail-transmitted helminths such as C. sinensis and intestinal protozoans has not.

A monoclonal antibody to cell surface antigen of human thymic epithelial cell

The cell surface molecule identified by a monoclonal antibody(TE-1) to human thymic epithelial cell showed the specificity for thymic epithelial cells of both the cortex and medulla. TE-1 reacted with the epithelial cells of normal thymus and thymoma in fresh frozen tissues. The antigen recognized by TE-1 was mostly confined to the cell surface membrane and arranged in reticular network with long processes between thymocytes. On immunohistochemical analysis, TE-1 did not recognize normal epithelial cells of the uterine cervix, skin and stomach, and neoplastic cells of squamous cell carcinoma and gastric adenocarcinoma, all of which were stained with anti-cytokeratin monoclonal antibody. Among the tumor cell lines tested with flow cytometry, most of epithelial and all of hematopoietic cell origin were not labeled with TE-1. In summary, TE-1 appears to be a monoclonal antibody against a surface antigen of human thymic epithelial cell that is immunohistologically different from known epithelial cell surface antigens reported so far.

MRI of Joubert's syndrome

OBJECTIVE

To report five cases of the rare Joubert's syndrome.

SUBJECTS

All five cases were studied by 1.0-Tesla MRI. All the patients showed typical clinical manifestations of Joubert's syndrome including neonatal respiratory abnormalities, developmental delay, ataxia, retinal atrophy and nystagmus.

RESULTS

The T1WI of MRI showed characteristic MRI features of Joubert's syndrome including dilatation of the fourth ventricle with some appearing bat-wing shaped, elongation and stretching of the superior cerebellar peduncles, dysphasia of the vermis, widening of the foramen of Magendie and the posterior cistern. One case was associated with encephalomeningocele.

CONCLUSIONS

MRI can provide characteristic findings of Joubert's syndrome and confirm the clinical diagnosis.

Simple aspiration of pneumothorax

The effectiveness of simple aspiration of pneumothorax with an intravenous cannula was evaluated in 34 patients who would otherwise have been treated by intercostal tube drainage with underwater seal. The procedure was successful in 25 patients (73.5%). The following features were associated with a successful outcome: (a) age below 50 years, (b) absence of underlying lung disease, (c) pneumothorax size not exceeding 50%, (d) volume of air aspirated less than 3000 ml, and (e) no previous pneumothorax. There were no complications encountered. Successfully treated patients benefitted from a shorter hospitalisation stay. The potential use of this procedure in treating selected patients in an outpatient setting should be explored.

Prognostic significance of ureteral obstruction in primary cervical cancer

OBJECTIVES

To evaluate the prognostic significance of ureteral obstruction in women with cervical cancer and the result of aggressive urinary diversion.

METHODS

The clinical history and X-rays of 52 women with Stage III and IV cervical cancer seen at Vanderbilt University between 1981 and 1991 were retrospectively reviewed.

RESULTS

Twenty-nine (55.8%) of these patients had unilateral [15] or bilateral [14] ureteral obstruction. There was no statistically significant difference in the survival of patients whether or not ureteral obstruction was present. Ten of fourteen women with bilateral ureteral obstruction and 4 of the 15 patients with unilateral obstruction underwent urinary diversion by percutaneous nephrostomy [9] or retrograde ureteral catheterization [5]. Complications were few. Although patients who underwent urinary diversion had somewhat better survival, it was not statistically significant.

CONCLUSIONS

Some patients with ureteral obstruction due to advanced cervical cancer can be salvaged by prompt, aggressive urinary diversion, but large trials are needed to validate this approach.

Evidence of antigen receptor-influenced oligoclonal B lymphocyte expansion in the synovium of a patient with longstanding rheumatoid arthritis

Plasma cell infiltration of synovium is common in longstanding rheumatoid arthritis (RA). The mechanism(s) underlying synovial B cell proliferation remains unclear. One theory invokes nonspecific polyclonal stimuli; another implicates antigen as the driving force. Antigen-driven repertoires are characteristically enriched for related sets of V gene segments containing similar sequence in the antigen binding site (complementarity-determining regions; CDRs). To study the forces shaping B cell proliferation, we analyzed V kappa transcripts expressed in the synovium of an RA patient. We found Humkv325, a developmentally regulated V kappa III gene segment associated with autoantibody reactivity, in > 10% of randomly-chosen synovial C kappa cDNAs. Two sets of sequences contained identical charged amino acid residues at the V kappa-J kappa join, apparently due to N region addition. We generated "signature" oligonucleotides from these CDR3s and probed PCR amplified V kappa products from the synovium and PBLs of the same patient, and from PBLs and spleen of individuals without rheumatic disease. Significant expression of transcripts containing these unique CDR3 sequences occurred only in the patient's synovium. Thus, in this synovium there is expansion of a limited set of B cell clones expressing antigen receptors that bear evidence of antigen selection.

[MRI of postmortem brains]

We studied 18 formalin-fixed brains using MRI, and correlated our data with subsequent gross and microscopic examinations. 9 of our patients died from brain diseases (stroke due to infarction 4, stroke due to hemorrhage 1, encephalitis 2, head injury 1, brain tumor 1). 9 of our patients died from non-CNS diseases (stomach cancer 1, colon cancer 1, liver cirrhosis 1, myocardial infarction 2, trauma 4). In MRI of postmortem brain, T1WI and T 2WI was able to clearly show the myelination process of brainstem, basal ganglia, internal capsule and optic radiation in a 2 months-old-boy. The findings were similar to MRI of live infants. In normal adult postmortem brains, the T1WI showed a relatively low signal intensity of white matter as compared to gray matter. The pictures were similar to proton density images, not T1WI of normal adult brains. The reason why the signal intensity of the white matter was lower than the gray matter may have been due to lysis of lipid of myelin sheath in the formalin solution. Postmortem MRI was able to detect the periventricular hyperintensity (corresponding to arteriosclerotic encephalopathy) and subcortical hyperintensity spots (which corresponding to the widening of the Virchow-Robin perivascular space because of arteriosclerosis) in the brains of our elderly patients. Postmortem MRI detected the intracerebral hemorrhage, which appeared as a dark signal in both short and long TR images. However, MRI did not show blood in the ventricles, sulci, or superficial hemorrhages in the cortex of brain. Brain edema was revealed in the postmortem MRI and appeared as low signal intensity in T1WI and hyperintensity in T2WI. It was associated with a significant mass effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of MR imaging of middle third esophageal carcinoma in determining resectability

Twenty-one patients with middle third esophageal carcinoma were prospectively evaluated by magnetic resonance imaging (MRI) to determine the resectability of the primary tumor. For 8 of the 21 patients, contrast medium was administered during the procedure. Evidences of aortic or tracheobronchial invasion shown on MRI were compared with surgico-pathologic findings, as well as mediastinal lymphadenopathy. Eleven patients (52%) had proved unresectable tumors (three cases of aortic invasion, five cases of tracheobronchial invasion and three cases of combined aortic and tracheobronchial invasion). In all eleven cases, these features were correctly detected by MRI. Two patients had false-positive findings on MRI. No patient had false-negative results. The sensitivity, specificity and accuracy were 100%, 80%, and 90% for MRI. Unsatisfactory results were obtained in evaluation of regional lymph node metastasis. Only two tumors in eight patients had good enhancement after contrast medium was given. We conclude MRI had a high accuracy in predicting resectability of tumors in patients with esophageal carcinoma.

Acute lobar nephronia: a case report

Acute lobar nephronia (ALN), a term analogous to acute lobar pneumonia, refers to a renal mass caused by acute focal infection without liquefaction. An alternative term is acute focal bacterial nephritis (AFBN). Fever, flank pain or back pain are the most frequently encountered clinical characteristics. Imaging modalities used to establish a definite diagnosis of acute lobar nephronia included sonography, computed tomography and nuclear medicine. Uroradiographic findings in this condition can mimic a renal abscess or neoplasm. Further distinction between acute lobar nephronia and other renal masses is aided by the appropriate use of renal sonography and computerized tomography is the most effective and least costly method in diagnosis. Serial sonograms can be used to monitor response to antibiotic therapy. Clinical and uroradiographic characteristics of a six year-old female patient with acute lobar nephronia are presented, along with a review of literature.

Response of fingertip circulation to local warming in the injured hand--a study using laser Doppler flowmetry

A laser Doppler flowmeter was used to assess the fingertip circulation serially in 41 patients with various hand injuries. The "flux value" measures the flow of red cells across the site of assessment and the "fluctuation" represents the pulsatile peak-trough difference in flux value with each cardiac contraction. Local temperature at the fingertip was raised stepwise by a special heater-thermostat from 36 to 44 degrees C. Compared to the normal hand both the flux value and fluctuation in the injured hand are smaller at lower temperatures. The differences narrow down at higher temperatures and the trend reverses above 42 degrees C and remains so on cooling. This may represent abnormal sympathetic tone in the injured hand.

Comparison of the effects of the laryngeal mask airway and endotracheal intubation on vocal function

We have compared changes in vocal function produced after insertion of a laryngeal mask airway (LMA) with those produced by tracheal intubation in 20 patients. Using acoustic waveform analysis, we computed amplitude variability (AV), pitch variability (PV), harmonics-to-noise ratio (HNR) and additive noise level (ANL) before anaesthesia and at 1, 4, and 24 h after tracheal extubation. There were no significant changes in vocal function after extubation except for HNR ratio (P = 0.046) at 4 h in the LMA group. There were differences in all four variables at 1 h, 4 h, or both, after tracheal extubation compared with baseline in the tracheal tube group. In both groups, all variables were the same as baseline values 24 h after extubation. We observed significant differences in AV (4 h), PV and ANL (1, 4 h) values between the two groups. These observations suggest that the LMA causes less vocal change than tracheal intubation.

Immunohistochemical detection of S-100, S-100 alpha, S-100 beta proteins, glial fibrillary acidic protein, and neuron specific enolase in the prenatal and adult human salivary glands

Developing human fetal salivary glands of gestational age from 10 to 40 weeks (n = 100) and normal adult glands (n = 10) were examined for immunoreactivity to S-100 protein and its subunits S-100 alpha, S-100 beta, glial fibrillary acidic protein (GFAP) and neuron specific enolase (NSE). In the early intermediate developmental stage (19-32 weeks) some acinar basal cells showed immunoreactivity to S-100 protein which rapidly disappeared in the late developmental stage (33-40 weeks). Adult salivary glands were negative for S-100 protein. The S-100 alpha subunit was strongly positive in the glandular ducts and acini of both fetal and adult glands. The S-100 beta, although present in some acini and ductal cells during the late intermediate developmental stage, was rarely seen in the adult glands. GFAP and NSE was positive at the developing salivary epithelium in the early developmental stage (15-18 weeks). The above findings indicated that the developing salivary epithelia showed transient appearance of the neuronal phenotype during active cytodifferentiation stage of glandular acini and ducts. Therefore, after evaluation of normal developmental and neoplastic transformation of the salivary glands a suggestion that neuronal differentiation of ductal reserve cells is responsible for the production of modified myoepithelial cells in both normal developmental salivary gland and neoplastic transformation is made.

Magnetic resonance imaging of cerebral hemiatrophy

Twenty-one cases of cerebral hemiatrophy were studied using 1.0 T magnetic resonance imaging (MRI). In addition to showing the generalized decrease in volume of the cerebral hemisphere, three patterns of cerebral hemiatrophy were noted: pattern I, diffuse cortical and subcortical atrophy (six cases):pattern II, diffuse cortical atrophy associated with expanded porencephalic cysts (10 cases); pattern III, old infarction with necrosis in the territory of the middle cerebral artery (five cases). Pattern I and pattern II were believed to have resulted from hypoxic-ischemic encephalopathy with subcortical leukomalacia (SCL). In all 21 cases, MRI also showed Wallerian degeneration, hyperintensive signals in the posterior limb of the internal capsule on the T2-weighted images, and unilateral atrophy of the cerebral peduncle as far as the pyramid of the medulla oblongata. Structural changes such as thickness of the calvarium, dilatation of the ipsilateral side of the frontal and ethmoid sinus, and reduced size of the middle cranial fossa, were found in 13 cases. Thus, MRI is a useful method of examination in the diagnosis of cerebral hemiatrophy as it has the ability to highlight changes in the cerebral hemisphere, basal ganglion, thalamus and brainstem as well as highlighting bony structural changes.

Transient intermediates of the methane monooxygenase catalytic cycle

Three new intermediates of the catalytic cycle of the soluble form of methane monooxygenase (MMO) isolated from Methylosinus trichosporium OB3b have been detected using transient kinetic techniques. MMO consists of hydroxylase (MMOH), reductase, and "B" (MMOB) components. MMOH contains an oxygen-bridged [Fe(III).Fe(III)] cluster that catalyzes O2 activation and insertion chemistry. At 4 degrees C, rapid mixing of O2 with diferrous MMOH ([Fe(II).Fe(II)]) in the presence of a 2-fold excess of MMOB resulted in loss of the g = 16 EPR signal characteristic of the diferrous cluster at an apparent first order rate of 22 +/- 5 s-1 (O2 approximately 700 microM). Subsequently, an EPR silent, chromophoric (lambda max = 330 and 430 nm, epsilon approximately 7500 M-1 cm-1 at each wavelength) intermediate (compound Q) formed with an average first order rate constant of 1 +/- 0.1 s-1 and then decayed at 0.05 +/- 0.01 s-1. Since compound Q formed much more slowly than diferrous MMOH disappeared, at least one other undetected intermediate (compound P) must have formed before compound Q. MMO substrates had little or no effect on the formation rate of compound Q, but they caused the decay rate to increase linearly with the concentration added. The substrates methane, furan, and nitrobenzene caused compound Q decay to occur with second order rate constants of 19,000 M-1 s-1, 9000 M-1 s-1, and 200 M-1 s-1 (+/- 5%), respectively. When nitrobenzene was used as a substrate, a second chromophoric intermediate (compound T, lambda max = 325 nm, with a shoulder at 395 nm, epsilon 395 approximately 6000 M-1 cm-1) formed at the same rate as compound Q decay. Chemical quench studies showed that compound T is an enzyme-product complex that decays with a rate constant of 0.02 +/- 0.005 s-1. This rate is approximately the same as kcat for nitrobenzene turnover at 4 degrees C catalyzed by the reconstituted MMO system, suggesting that product release is the rate-limiting step in catalysis. The characteristics of compound Q suggest that it may be the activated form of the enzyme that directly catalyzes substrate oxidation.

Cytomegaloviral acalculous cholecystitis in acquired immunodeficiency syndrome patients

Abdominal pain and fever in patients with the acquired immunodeficiency syndrome (AIDS) may indicate cytomegaloviral (CMV) acalculous cholecystitis. We reviewed clinical, laboratory, and outcome data from 12 patients with CMV cholecystitis. Ten of 12 patients were homosexual males. Six patients had markedly low CD4: CD8 lymphocyte count ratios. Total leukocyte counts were normal or decreased, serum liver function tests normal or cholestatic, and only one patient had hyperbilirubinemia. Sonographic transmural gallbladder edema is typically more severe than expected for the presenting illness. Five of six patients investigated with HIDA scintigraphy had a nonvisualizing gallbladder. Open cholecystectomy had a 9.1 per cent operative morbidity and a 0 per cent mortality. Cholecystectomy is a safe and curative intervention, regardless of the immunocompromised condition of the host. Intraoperative cholangiography will identify papillary stenosis or sclerotic bile ducts as a potential cause of recurrent symptoms following surgery. A search for other sites of tissue invasion by CMV should follow cholecystectomy.

JL1, a novel differentiation antigen of human cortical thymocyte

Expression of a novel thymocyte differentiation antigen, JL1, defined by a monoclonal antibody (mAb) developed against human thymocytes showed a specificity for stage II double positive (CD4+CD8+) human cortical thymocytes. This antigen was not expressed at detectable levels on medullary thymocytes, mature peripheral leukocytes, bone marrow cells or on other types of tissues elsewhere in the human body. Immunohistologic analysis revealed that JL1 had a clear pattern of distribution on cortical thymocytes. Immunoprecipitation of 125I-labeled cell lysates from human thymocytes and Molt-4 leukemic cell line with anti-JL1 mAb yielded a 120-130-kD single chain glycoprotein. When immunoprecipitation of cell lysate was done after endoglycosidase F treatment, JL1 antigen was still detected by antibody but the band showed a reduction in apparent molecular mass of approximately 5 kD. This suggests that, although JL1 molecule contains carbohydrate group, this does not form a critical part of the antigenic determinant for anti-JL1 antibody. JL1 antigen appears to be the first double positive, stage-specific differentiation antigen of human thymocyte reported so far. This antigen would be a useful marker for lymphoblastic malignancy of stage II thymocyte origin and it may be involved in the thymocyte education process.

[The chemical shift imaging of liver]

Tissue characterization of different pathologies of the liver can be achieved by differences of relaxation time on changing of pulse sequences in magnetic resonance imaging (MRI). The usefulness of MRI for detection of liver disease is limited when the pathological change is subtle. Chemical shift is a fundamental characteristics in nuclear magnetic resonance (NMR). Chemical shift imaging (CSI) in MRI is based on the different Larmor frequency of proton in water and fat; and therefore it was able to enhance the effectiveness of pathology. For this study, Dixon's method was used to detect liver pathologies and compare its detectability with conventional pulse sequences. Forty cases were enrolled for study; they included 5 health volunteers, 15 hepatomas, 1 cholangiocarcinoma, 5 metastatic hepatic tumors and 14 fatty livers. In hepatic tumors, the lesion number, tumor margination and lesion-to-liver contrast in images were read and analyzed. Signal intensities, signal-to-noise ratio and contrast-to-noise ratio were compared, after measurement, from stored data. In fatty livers, the relative change of signal intensities in different areas of the liver in in-phase and out-phase images were compared with the back muscle and spleen to find where the fatty metamorphosis happened. CSI in spin echo or gradient echo pulse sequences was found to be adequate and valuable for detecting fatty liver, when compared with conventional MRI. CSI not only identified the extension of disease itself but also characterized the fatty change in liver parenchyma. Though CSI affords no further advantages than conventional pulse sequences for detection of hepatic tumors, occasionally, when the image quality of the conventional pulse sequences is not satisfactory or equivocal in lesion detection, the use of CSI might be attempted.

Myelography, CT and MRI in leukaemic infiltration of the lumbar theca

A 25-year-old woman with acute lymphoblastic leukaemia, while in remission, developed paraparesis, with faecal and urinary incontinence. CT demonstrated increased density of the lumbar theca and enlargement of the nerve roots. Myelography showed complete obstruction below the L3 level. MRI showed increased signal intensity in the lumbar sac on T1 weighting, and the cauda equina enhanced with gadolinium-DTPA. Lymphoblasts were seen in the lumbar spinal fluid. After chemotherapy, these abnormalities resolved, as did the paraparesis and incontinence.

Combined chemotherapy and radiation for bulky stages I-II cervical cancer: comparison of concurrent and sequential regimens

Based on analysis of 5-year survival rates among 386 patients with carcinoma of the cervix treated between 1976 and 1984 at Yonsei University College of Medicine, high risk factors have been defined which identify patients with a poor prognosis when treated with radiation alone. Among patients with FIGO Stages I-II disease, lesions > or = 4 cm were indicative of a higher risk of treatment failure. Between 1984 and 1991, 39 patients with Stages I-II large cell squamous cancers > or = 4 cm in diameter were treated with radiation alone. Between 1984 and 1989, 19 comparable patients were treated with sequential chemotherapy consisting of two or three cycles of cisplatin at 100 mg/m2 and a 5-day infusion of 5-fluorouracil at 1000 mg/m2/24 hr. Between 1988 and 1991, 37 comparable patients were treated with concurrent radiation and one to six cycles of chemotherapy employing the same or equivalent drug and dose schedule. The radiation techniques, dose, and fractionation employed were similar in the three groups. The 30-month survival rate was 100, 89.5, and 79.5% (P < 0.05) following concurrent treatment, sequential treatment, and radiation alone, respectively. Response to chemotherapy administered in cycles was evaluated before instituting radiotherapy in the patients treated with sequential chemotherapy and radiation. In conclusion, the combination of radiotherapy and chemotherapy appeared superior to radiation alone, and the toxicity of combined modality therapy is manageable. Also concurrent chemotherapy may be slightly better than sequential chemotherapy and radiation, and given the lesser overall treatment time and expense, this has become the preferred mode of treatment in our institution.

HPV-1 capsids expressed in vitro detect human serum antibodies associated with foot warts

Seventy-eight human serum samples were screened for their ability to immunoprecipitate the major (L1) and minor (L2) capsid proteins of HPV1. The L1 and L2 proteins expressed from a recombinant vaccinia virus were able to self assemble into capsids in the nuclei of infected cells. Twenty-eight of the sera precipitated the L1 protein. The L1 protein was only precipitated when the protein was native, denatured protein was not precipitated by the human sera. None of the sera precipitated the L2 protein. The assay demonstrated a significant association between the ability of sera to precipitate the L1 protein and a clinical history of foot warts (P = 0.001). The same serum samples were tested by immunoblots using L1 and L2-trpE bacterial fusion proteins. It was found that almost half of the sera reacted with the L2 fusion protein and few reacted with the L1 protein. Immunoblot results did not correlate well with a clinical history of foot warts (P = 0.7), suggesting that immune precipitation of capsid proteins may be superior to immunoblotting for serodiagnosis of HPV infections.

Effects of cytochalasin B on calcium transport by 1,25(OH)2D3- or PTH-treated chick embryonic yolk sac in vitro and in vivo

The present study was done to elucidate the mechanism(s) by which calcium is taken up or transported across the yolk sac membrane of the embryonic chick. We examined the effect of various inhibitors or experimental conditions on the uptake of calcium in vitro. Treatment with ouabain, verapamil, antimycin A and calcium ionophore A23187; substitution of choline for sodium or potassium in the buffer; or incubation of the tissue at 0 degree C had no significant effect on calcium uptake by the yolk sac membrane. Dinitrophenol (DNP) and lanthanum chloride (LaCl2) reduced 45Ca uptake from day 6 and 9 embryos by 15% and 30%, respectively. Cytochalasin B decreased the uptake of 45Ca in yolk sac membrane disks of day 6 embryos, but not in older embryos. The effects of cytochalasin B were explored further in embryos pretreated with either 1,25(OH)2D3 or PTH, both of which enhance calcium uptake. Cytochalasin B decreased calcium uptake in 9-day and 12-day vitamin D-treated embryos to about 60% of their hormone-enhanced level and also decreased PTH-stimulated 45Ca uptake into yolk sac disks by about 50% in embryos of all age groups tested. We also examined the effect of cytochalasin B on 45Ca transport across the yolk sac membrane in vivo. Cytochalasin B did not affect this transport in control (vehicle-treated) embryos. However, it significantly decreased the enhanced in vivo 45Ca transport in day-9 and -12 vitamin D-treated embryos approximately 30% and 45%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of immunoglobulin gamma heavy chain expression in synovial tissue of a patient with rheumatoid arthritis

OBJECTIVE

To gain insight into mechanisms underlying local immune responses in rheumatoid arthritis (RA), we analyzed the utilization of variable-region heavy chain (VH), diversity (DH), and joining (JH) gene segments expressed in synovial tissue of a patient with RA.

METHODS

An unrestricted complementary DNA (cDNA) library was generated from unselected cells extracted from synovial tissue obtained at the time of joint replacement. Southern blot analysis for VH, JH, and C gamma subclass utilization was performed on the first 50 C gamma- and JH-positive recombinants for which phage DNA was isolated. Eighteen of the clones were selected at random for sequence analysis. The VH gene segments were compared with an extensive database of germline and cDNA sequences.

RESULTS

All transcripts utilized gene segments from the VH1 (28%), VH3 (56%), and VH4 (15%) families. There was a predominance of JH4, JH5, and JH6 gene segment utilization. Fourteen of 18 randomly sequenced clones contained sufficient VH-region information for analysis. Eight (57%) were most closely related to VH gene segments that are preferentially expressed in human fetal liver or that encode antibodies with self-reactivity. The variable domains were heavily mutated, and replacement-to-silent substitution ratios (R:S ratios) in the antigen-binding domains (complementarity-determining regions [CDRs]) were disproportionately high. CDR3 lengths were quite variable, due to extensive N-region addition and 5'-exonuclease activity in the VH-DH-JH joins.

CONCLUSION

Plasma cells in this synovial tissue sample appear to express VH gene segments that are preferentially utilized during fetal development or in autoantibodies. The JH repertoire is similar to that seen in adult peripheral blood lymphocytes, but much different from that found during fetal development. The large number of somatic mutations and the high R:S ratios in the CDRs suggest an antigen-driven response.

Rib counting on CT using the sternal approach

To devise a new method for counting ribs on CT scan, we evaluated the CT anatomy of the costal cartilages and the proximal xiphoid in 20 control patients without rib pathology. The sternal end of costal cartilages seen on the same image as the proximal xiphoid was always the seventh (n = 20). These costal cartilages were located anterolateral (n = 13) or lateral (n = 7) to the proximal xiphoid. In fifteen patients with rib pathology, 23 abnormal ribs were localized by our method. All of these ribs correlated with those seen on chest radiographs and rib cage views or with resected ribs on postoperative films.

Prenatal development of myoepithelial cell of human submandibular gland observed by immunohistochemistry of smooth muscle actin and rhodamine-phalloidin fluorescence

Immunostaining of monoclonal antibody (MoAb) of smooth muscle actin in paraffin sections and fluorescence of actin-specific phalloidin in cryostat sections were utilized to demonstrate the myoepithelial cells in prenatal and adult salivary glands of humans. In the early developmental stage (10-18 weeks) MoAb actin was weakly positive in the basal cells of the gland epithelium, and the positivity gradually accentuated at the basal portions of the terminal ducts and acini as the gestational period advanced. In the early intermediate developmental stage (19-24 weeks) the polyhedral myoepithelial cells were arranged in the basal portions of the acini and intercalated ducts. At this stage the myoepithelial cells produced phalloidin-positive spindle cytoplasmic processes. In the late intermediate developmental stage (25-32 weeks) the myoepithelial cells became flattened and formed dendritic processes to surround the acini and intercalated ducts. In the late developmental stage (33-40 weeks) numerous myoepithelial cells with well developed dendritic processes were demonstrable in the acini and intercalated ducts. In conclusion, it was found that the myoepithelial cells began to develop at 15-16 weeks of gestation when the acinar cells were still immature. The primitive myoepithelial cells were polyhedral in shape to form compact basal layer beneath the developing acinar cells during 19-24 weeks of gestation. In late gestational period the myoepithelial cells almost matured like the dendritic ones of adult salivary glands. However, the myoepithelial cells were never demonstrated in the striated and excretory ducts of the fetal salivary glands as opposed to its normal presence in the adult salivary glands. A possible aging process of myoepithelial cells was discussed in accordance with the histogenesis of transformed myoepithelial cells of salivary gland tumors.

Detection of renal allograft dysfunction with color Doppler flow ultrasound

Thirty-six color Doppler flow (CDF) ultrasound studies were performed on 28 allograft kidneys to assess the capability of this technique in diagnosing transplant dysfunction through morphology and Doppler spectra. The composite score obtained from ultrasound images showed no statistical significance. Quantitative studies with Pulsatility Index (PI) and Resistive Index (RI) after localization of the arcuate, interlobar, segmental and main renal arteries by CDF revealed significant differences between normal functioning graft kidneys and the group of acute rejection, as well as the group of acute tubular necrosis (ATN) (P < 0.05). No apparent change was demonstrated in patients with chronic rejection. When PI was greater than 1.60 or RI was greater than 0.80, the transplant kidney was more likely to be rejected, though possibility of ATN should be considered. RI was easier to calculate, and correlated better than PI with the serum creatinine level. CDF expedited the Doppler spectrum study.

[Evaluation of radiation doses in mammography]

A dedicated X-ray mammography was introduced to our hospital from 1987 and an imaging receptor of xeroradiography was applied. We reported previously that the average air exposure was 0.79R and that the absorption dose of skin was 1.00 rad. These data are similar to literature reports. Screen-film mammography was introduced recently. To select the best breast imaging and the least radiation exposure, diverse methods were investigated. A dosimetry (Capintec model 192) and a PS-033 parallel ionization chamber were applied to compare the absorption dose on polystyrene phantom between various exposure factors, the application of breast clamp and the size of exposure field. Retrospective estimation of the radiation dose was obtained from the exposure factors of previous mammography since July, 1990 to May, 1992. There were 1035 xeromammographic examinations and 358 examinations with medium-speed screen-film mammography. Another 61 craniocaudal and 96 mediolateral projections with high-speed screen-film mammography were recruited during the recent two months. An ionization chamber (Exradin, Shonka-Wyckoff A5) with an electrometer (Keithley 617) wer selected to obtain the dose equivalent from air exposure between selected exposure factors. The radiation dose of mammography is linearly correlated with voltage/kV and current/mAs. The application of a breast clump reduces 10% of the skin dose. The average exposure factors of xeromammography are 45.6 kV, 163.5 mAs. These results remain the same as in our previous report. Xeromammography has a greater exposure to air, estimated average glandular dose and absorbed dose than screen-film mammography. The mean exposure factor of rapid screen-film mammography gains half the value of medium screen-film mammography, ie. 26.6 kV, 87.0 mAs vs. 26.0 kV, 164.5 mAs.(ABSTRACT TRUNCATED AT 250 WORDS)

Melanin pigments and melanosomal proteins as differentiation markers unique to normal and neoplastic melanocytes

This report introduces some aspects of our current basic research focus on the unique metabolic pathways within the melanocyte. Using this approach, we hope to gain a better understanding of the pathophysiology of malignant melanoma and develop early laboratory diagnostic tests for this disease. Specifically, we will discuss that: 1) the synthesis of pheomelanin is markedly increased in malignant melanoma and dysplastic melanocytic nevi; 2) high levels of metabolites of pheomelanin and eumelanin can be detected in the urine and blood of patients with metastatic melanoma; 3) this release of melanin metabolites appears to correlate with tumor thickness and tumor load, including the extent of metastasis; 4) the synthesis of melanosomal proteins also becomes aberrant in malignant melanoma; and 5) this abnormal melanosome synthesis can be utilized in the identification of antigenic epitopes that are uniquely expressed in malignant melanoma. We believe that this synthesis and secretion of abnormal melanin pigment and melanosomal proteins (human melanosome-specific antigen) would be useful for the development of early laboratory diagnostic and monitoring tools for malignant melanoma. In addition, we also report the detection of pheomelanin component in "normal" unexposed skin; however, the relative amount of pheomelanin in the skin does not reflect hair color (e.g., red hair). The nature of this pheomelanin component in the skin needs to be further clarified.

Mosquito DNA polymerase epsilon

The mosquito homolog of mammalian DNA polymerase epsilon, formerly known as a proliferating cell nuclear antigen (PCNA)-independent form of DNA polymerase delta, has been purified from mosquito larval extracts. The polymerase epsilon was separated from DNA polymerase alpha by chromatography on hydroxylapatite, and the enzyme was subsequently purified on single-stranded DNA agarose, followed by a 5' AMP-agarose chromatography step. The purified polymerase exhibits an intrinsic 3'-5' exonuclease activity and shows high activity using an oligo-primed DNA template. Neither human nor Drosophila PCNA stimulated this polymerase activity. Additional immunochemical and biochemical evidence indicates that this enzyme is distinct from DNA polymerase alpha.

Ependymoma of the cauda equina presenting with subarachnoid hemorrhage

A 16-year-old girl had an ependymoma at the L2 and L3 level that bled into the dural sac, presenting clinically as intracranial subarachnoid hemorrhage. MR depicted the tumor and hemorrhage on both T1- and T2*-weighted images. The blood in the dural sac appeared hyperintense on the T1-weighted images.

Neurilemmoma of the oculomotor nerve presenting as an orbital mass: MR findings

Neurilemmoma of the oculomotor nerve is rare and infrequently presents as an orbital mass. We report a neurilemmoma arising from the cavernous sinus with its major part extending into the orbit. The Antoni A part of the neurilemmoma showed intermediate signal intensity in both T1- and T2-weighted MR images and exhibited postcontrast enhancement. The Antoni B part revealed hypointensity on T1-weighted images, hyperintensity in T2-weighted images, and showed no contrast enhancement.

Disseminated tuberculomas in spinal cord and brain demonstrated by MRI with gadolinium-DTPA

Intramedullary tuberculoma is rare, and there has been no report of concurrent intramedullary and intracerebral tuberculomas. We report a 30-year-old man with miliary tuberculosis of the lung. He suffered sudden paraplegia due to tuberculomas in the thoracic spinal cord and MRI showed more tuberculomas in the cervical spinal cord, brain stem, and cerebral and cerebellar hemispheres. The tuberculomas were isointense on the T1-weighted images, and hyperintense on the T2-weighted images; there was marked enhancement with intravenous gadolinium-DTPA. All the tuberculomas were very small 1 year after antituberculous chemotherapy.

[Sonographic patterns and pathological correlation of neuroblastoma]

This study prospectively correlated pathological findings with sonographic results in two cases of neuroblastoma, and retrospectively analyzed the sonographic pattern of neuroblastomas encountered in our hospital in past years. Prospectively, among the five pathologically proved neuroblastomas, only two received operation. The removed specimens were scanned by high resolution ultrasound, and selected areas were guided by a needle for pathological correlation. Pathologically, the hyperechoic region represented tumor necrosis, hemorrhage and calcifications, as well as hypercellularity and irregular arrangement of the neurofilaments. The hypoechoic areas showed less cellularity with loose tumor cells. No pseudorosette formation was noted. In the retrospective study, 26 neural crest tumors were collected, but only 14 cases received sonographic examination. The most common sonographic findings were heterogenous mixed pattern (65%) and heterogenous hyperechoic pattern (21%). Eleven cases showed calcifications. Two cases presented with echogenic lobule. Most of the tumors were larger than 8 cm, ill-defined and grew across the midline (73%). Sonography is advantageous for diagnosis of abdominal mass in children and might be helpful in differentiating neuroblastomas from other tumors.

Immunohistochemical study of lymphoid tissue in human fetal salivary gland

Immunoreactivity of lysozyme (LY), lactoferrin (LF), alpha 1-antichymotrypsin (alpha 1-ACT), alpha 1-antitrypsin (alpha 1-AT), keratin proteins KL1, PKK1, K8.12, S-100 protein, MAM-3, MAM-6, and epithelial membrane antigen (EMA) were evaluated in lymphoid and glandular tissues of developing salivary gland of human fetus (gestational age ranging from 17 to 40 wk to investigate the role of lymphoid tissue in developing salivary glands. In a total of 79 cases, lymphoid cell aggregations were noted in parotid (57 cases), submandibular (21 cases) and sublingual (5 cases) glands. Mononuclear cells showing intense activity of LY, alpha 1-ACT and alpha 1-AT were present in the lymphoid aggregation. The glandular ducts embedded in lymphoid tissue were negative to MAM-3, MAM-6, EMA and S-100 protein, but showed positive PKK1 and KL1 reaction during early stages of development, and showed degeneration and effacement upon increase in number and LY activity of the mononuclear cells. The lymphoid aggregations progressively emerged as lymph nodes.

Methane monooxygenase component B and reductase alter the regioselectivity of the hydroxylase component-catalyzed reactions. A novel role for protein-protein interactions in an oxygenase mechanism

The soluble methane monooxygenase (MMO) system, consisting of reductase, component B, and hydroxylase (MMOH), catalyzes NADH and O2-dependent monooxygenation of many hydrocarbons. MMOH contains 2 mu-(H or R)oxo-bridged dinuclear iron clusters thought to be the sites of catalysis. Although rapid NADH-coupled turnover requires all three protein components, three less complex systems are also functional: System I, NADH, O2, reductase, and MMOH; System II, H2O2 and oxidized MMOH; System III, MMOH reduced nonenzymatically by 2e- and then exposed to O2 (single turnover). All three systems give the same products, suggesting a common reactive oxygen species. However, the distribution of products observed for most substrates that are hydroxylated in more than one position is different for each system. For several of these substrates, addition of component B to Systems I, II, or III causes the product distributions to shift dramatically. These shifts result in identical product distributions for Systems I and III in which MMOH passes through the 2e- reduced state ([Fe(II).Fe(II)]) during catalysis. In contrast, System II (in which MMOH probably does not become reduced) generally gives a unique product distribution. It is proposed that changes in MMOH structure occurring upon diiron cluster reduction and/or component complex formation cause substrates to be presented differently to the activated oxygen species. Kinetic studies show that component B strongly activates System I and, in most cases, strongly deactivates System II. The effect of component B on product distribution of System I (and III) occurs at less than 5% of the MMOH concentration, while nearly stoichiometric concentrations are required to maximize the rate of System I. This shows that component B has at least two roles in catalysis. EPR monitored titration of reduced MMOH ([Fe(II).Fe(II)]) with component B suggests that the effect of substoichiometric component B on product distribution is due to hysteresis in the MMOH conformational changes.

Maxillo-mandibular development in cerebrocostomandibular syndrome

Cerebrocostomandibular syndrome is a potentially lethal developmental disorder characterized by mental handicap, palatal defects, micrognathia, and severe costovertebral defects. We report a 3-day-old male neonate who died of respiratory difficulty that began at birth. Micrognathia, glossoptosis, high-arched palate, and hypoplasia of the lower half of the face were present. Multiple posterior rib defects and a narrow rib cage were associated with pulmonary hypoplasia. The rib gaps were filled with fibrovascular tissue. A facial bone study showed multifocal growth retardation involving the septal cartilage, vomer, and mandibular condyle, indicative of maxillomandibular growth arrest. The tongue had an abnormal genioglossus muscle and papillae.

Clinical application of ejection fraction by gated MRI

To evaluate the clinical desired accuracy of the left ventricular ejection fractions (EFs) calculated by magnetic resonance imaging (MRI). Within one to three days post coronary angiography and left ventriculogram, twenty-five adults were studied by MR imaging. They had nuclear medicine studies for left ventricular ejection fractions as well. EKG-gated spin-echo 30-msec echo-delay images were obtained in end systole and end diastole in a plane parallel to the ventricular septum. Analysis of ventricular volumes and ejection fractions were performed using the area-length method. The EFs calculation by gated MRI were compared with that obtained by angiocardiography and nuclear medicine studies. The linear regression line obtained for ejection fraction was y = 0.858x +6.813, r = 0.753, p = 0.009; y' = 1.567x'-24.692, r' = 0.783, p' = 0.002. The above figure indicate a reasonable correlation among these three methods.

[Detection of the myelination process of Chinese infants by 1.0T MRI]

To establish the myelination process of brain of Chinese infants, our study consisted of seventy-five infants ranging in age from 5 days to 2 years old. They were studied with a 1.0 T superconductive MRI. In the new born, myelination could be seen in the brainstem, middle cerebellar peduncle, and posterior limb of the internal capsule in both T1WI and T2WI. Then the myelination process rapidly progressed month by month. Myelination of the centrum semiovale and optic radiation could be seen in T1WI in the newborn up to 3 months old, and in T2WI at 3-5 months old. The myelination of the splenium and the genu of corpus callosum were seen at 3-6 months in T1WI and 5-6 months in T2WI. Myelination of the occipital lobe and frontal lobe were seen at 3-6 months and 5-10 months in T1WI, and 8-14 months, 10-16 months in T2WI respectively. In 7-10 months, the brain appeared as an "early adult pattern" in T1WI; while, in T2WI, the brain appeared as an "early adult pattern" at 14-18 months old. The understanding of the myelination process in infants is important and essential for the judgement of the infantile brain and for the diagnosis of many CNS diseases of infants.

A rheumatoid factor from a normal individual encoded by VH2 and V kappa II gene segments

OBJECTIVE

To gain insight into the immunoglobulin variable-region repertoire of anti-IgG antibodies (rheumatoid factors [RF]), we characterized the VH and V kappa gene segments utilized in an IgM-RF-secreting lymphoblastoid cell line (SSH23) isolated from a normal individual.

METHODS

The cell line SSH23 was established by Epstein-Barr virus transformation of peripheral blood non-T mononuclear cells. First-strand complementary DNA (cDNA) was generated and used for polymerase chain reaction amplification of the heavy and light chain variable domains. The amplified variable domains were sequenced and compared with an extensive database of germline and cDNA V gene segments.

RESULTS

The VH sequence was found to be identical to a previously described fetal VH2 incomplete cDNA and to differ by only 3 nucleotides from a JH proximal germline VH2 gene segment. To our knowledge, this is the first example of a VH2 rheumatoid factor. The V kappa 2-J kappa 4 light chain contains an uncommon 10-amino acid third complementarity-determining region (CDR 3).

CONCLUSION

Utilization of preimmune fetal VH gene segments and unusual light chain junctional diversity appear to be features shared by many physiologic and pathologic rheumatoid factors.

The immunoglobulin kappa light chain repertoire expressed in the synovium of a patient with rheumatoid arthritis

OBJECTIVE

To analyze the nature of the B cell response in the synovial tissue of a patient with rheumatoid arthritis (RA). Specifically, we sought to determine if the pattern of immunoglobulin expression was consistent with polyclonal stimulation of B cells or an antigen-driven response.

METHODS

We generated an unrestricted complementary DNA (cDNA) library from the diseased synovium of a rheumatoid factor (RF)-positive patient with an 18-year history of RA. A random sample of kappa light chain recombinants was identified, and sequence analysis was performed. The variable domains were compared with an extensive database of germline and cDNA kappa sequences.

RESULTS

We found a light chain repertoire enriched for kappa transcripts containing 2 V kappa gene segments (Humkv325 and Humkv328) that are frequently associated with paraproteins expressing RF activity. Kappa variable domains from synovium contained numerous somatic mutations which resulted in frequent replacement of amino acids that encode the classic antigen-binding site. Unexpectedly, many of these kappa transcripts contained non-germline-encoded nucleotides (N regions) at the site of V kappa-J kappa joining. The combination of N-region addition and variation in the sites of V kappa-J kappa splicing generated unusually long complementarity-determining region 3 regions and charged amino acids near the V kappa-J kappa splice site.

CONCLUSION

The pattern of somatic mutations found in this patient sample supports the hypothesis that these synovium-derived plasma cells are the product of immunoglobulin receptor-dependent (i.e., antigen-driven) selection. The extent of N-region addition raised the additional possibility that these antibodies derive from an unusual set of B lymphocytes that have escaped normal regulation.