Optimalization of southwestern technique for detection of binding of Epstein-Barr virus nuclear antigen 1 to origin of replication

An optimized protocol of Southwestern analysis for detection of Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA-1) binding to the origin of viral replication (oriP) was described. The unique feature of this optimized protocol includes the restoration of the denatured proteins to native conformation after SDS-polyacrylamide gel electrophoresis and blocking of nonspecific and low-affinity binding sites prior to DNA binding. The parameters and conditions that may affect the specific interaction of EBNA-1 to oriP DNA were then determined. The specific binding was affected by divalent cations (MgCl2) and ionic strength; the optimal concentrations of MgCl2 and NaCl were observed at 10 and 300 mM, respectively. The various buffer systems and pH values tested had no apparent effect on EBNA-1 binding. Under the optimal conditions, a single protein of 68 Kd was detected and the bindings of other nonspecific, low-affinity DNA-binding proteins were abolished. The authenticity and specificity of 68 Kd protein as EBNA-1 were determined by reaction with antibody specific for EBNA-1 and competition assay with specific DNA sequence. After optimization this technique can be a powerful and yet simple means of studying protein-DNA interactions and their roles in gene expression.

Diagnostic and therapeutic video-assisted thoracic surgery resection of pulmonary metastases

BACKGROUND

Appropriateness of video-assisted thoracic surgery (VATS) pulmonary metastasectomy for curative intent has been a controversial topic. We reviewed our experience with VATS wedge resection for peripheral lung metastases to determine the efficacy and potential adverse consequences of this approach for pulmonary metastasectomy.

METHODS

One hundred seventy-seven patients underwent VATS resection of pulmonary metastases. Diagnostic resection (VATS-dx) was performed for 78 patients when percutaneous biopsy was unsuccessful or not feasible. Potentially curative resections (VATS-rx) were performed for 99 patients. The histologic findings in this group included colorectal (68), renal (7), sarcoma (6), breast (4), melanoma (3), head/neck (3), lymphoma (2), uterine (1), and "other" (5). The average number of lesions resected was 1.4 (range, 1-7).

RESULTS

VATS resection was successfully performed for all VATS-dx and VATS-rx patients. There were no perioperative deaths. Longitudinal follow-up demonstrated a mean survival of 18 months in the VATS-dx group and 28 months in the VATS-rx group. In the VATS-rx group, 37 (37%) of 99 were free of disease, at a mean follow-up interval of 37 months. Of the 57 recurrences, 5% were local, 26% were regional, and 69% were distant.

CONCLUSIONS

Results with VATS resection of peripheral pulmonary metastases for diagnostic and potentially curative intentions appear comparable with historical results by "open" thoracotomy. Careful patient selection based on high-resolution helical CT scanning is important to avoid compromise of therapeutic intent. Conversion to thoracotomy is indicated when lesions identified preoperatively are not found or when technical problems encountered may compromise surgical margins when resecting lung metastases for potential cure.

The external granule layer of the developing chick cerebellum generates granule cells and cells of the isthmus and rostral hindbrain

The external granule layer (EGL) on the dorsal surface of the developing cerebellum consists of neural progenitors originating from the rostral rhombic lip (RRL). The RRL and the EGL were thought to give rise exclusively to the granule neurons of the cerebellum (Alder et al., 1996). To study the fate of individual RRL cells, we used a retroviral library to mark clones in the chick embryo at Hamberger-Hamilton stages 10-12. RRL clones comprised the EGL and cerebellar granule cells, as expected. Surprisingly, however, as many as 50% of the RRL clones also contained cells ventral to the cerebellum proper. Ventral derivatives were found in clones with a medial origin, as well as in those with a lateral origin along the RRL. Some of the ventral progeny appeared to be in the process of migration, whereas others appeared to be differentiating neurons in the isthmus and the rostral hindbrain region, including the locus coeruleus (LC) and pontine reticular formation. Furthermore, the Phox2a marker of LC precursors was detected in the EGL within the anterior aspect of the cerebellum. A stream of cells originating in the EGL and expressing Phox2a was observed to terminate ventrally in the LC. These data demonstrate that single RRL progenitor cells are not restricted to producing only cerebellar granule cells; they produce both cerebellar granule cells and ventral derivatives, some of which become hindbrain neurons. They also suggest that some progeny of the EGL escape the cerebellum via the anterior aspect of the cerebellar peduncles, to contribute to the generation of ventral structures such as the LC.

Detailed deletion mapping with a refined physical map of 7q31 localizes a putative tumor suppressor gene for breast cancer in the region of MET

In breast cancer, loss of heterozygosity (LOH) has been described on the long arm of chromosome 7 at band q31, suggesting the presence of a tumor suppressor gene in this region. To define the deleted region, we analysed 73 cases of breast cancer and matched normal DNAs with 17 polymorphic markers. A minimal area of LOH was identified as the chromosomal interval flanked by markers D7S687 and metH, spanning a segment of 2 Mb on chromosome 7q31. Of the 73 breast cancer patients studied, all were informative for at least one marker in this region and nine patients showed LOH at one or more loci (12.3%). To define the physical size of the deletion and to ensure the correct interpretation of the LOH deletion studies, we redefined the physical map of markers within this region of 7q31. We present a new physical order for markers at 7q31. More significantly, we have mapped the minimum deletion of 7q31 in the breast cancers studied to date to a physical distance of 1000 kb, contained on a single YAC clone, which includes the MET receptor tyrosine kinase but no other known genes.

Magnetic necklace: its therapeutic effectiveness on neck and shoulder pain

The effect of the magnetic necklace on chronic neck and shoulder pain was studied on 101 volunteers, 46 males and 55 females. A double-blind method was applied on 4 divided groups (with pain vs without pain matched with magnetic vs nonmagnetic necklace). All the subjects wore the necklace 24 hours per day for 3 weeks. Subjective evaluation from the subjects with pain, either with magnetic or nonmagnetic treatment, was performed before and 3 weeks after the necklace treatment, and revealed a significant placebo effect in terms of decrease in intensity or frequency of pain. The objective tests with electrodiagnostic procedures were done before the treatment and at 3 weekly intervals. The proximal conduction time of the ulnar nerve was significantly reduced by magnetic treatment in the subjects without pain but was not changed in the subjects with pain. There was no significant change in the excitation threshold of the suprascapular nerve in all subjects. The possible mechanism of magnetic effects on pain and the prospect of magnetotherapy for pain relief in physical medicine are discussed.

Early CT findings of acute cerebral infarction in the middle cerebral artery territory

For an early and definitive diagnosis of acute cerebral infarction by computed tomography (CT), we retrospectively analyzed the initial CT findings of 14 patients with proven acute middle cerebral artery (MCA) infarction within 4 hours after stroke onset. The following results were obtained: (a) abnormal CT findings could be recognized quite early in 13 patients (92.9%), (b) the most common and earliest finding was loss of defination of the gray-white interface at the lateral margins of the insula. This sign was recognized in 12 patients (85.7%) and could be detected as early as 1 hour after stroke onset, (c) the next common finding was narrowing or blurring of the Sylvian fissure in 10 patients (71.4%) and could be detected 1.5 hours after stroke onset, (d) an obscured outline or partial disappearance of the lentiform nucleus was recognized in 7 patients (50%) and could be detected 1.5 hours after stroke onset, (e) effacement of the cerebral sulci was found in 6 patients (42.9%) and could be detected 2.5 hours after stroke onset, (f) increased density in MCA or its major branches was not seen in our patients.

Mycobacterium smegmatis keratitis after radial keratotomy--a case report

A 42-year-old woman who developed a corneal ulcer in the left eye after radial keratotomy. The acid-fast stain showed that numerous clusters of acid-fast bacilli and Mycobacterium smegmatis were isolated on the culture. To the best of our knowledge, this is the first documented case of Mycobacterium smegmatis keratitis in the world literature. The sensitivity test showed that this organism resistant to all the anti-tuberculous agents and antibiotics we test. An initial response to amikacin and kanamycin was found, but relapse of infiltrate was noted one month later. The regimen was therefore changed to a combination of amikacin with ofloxacin. This patient had a favorable response to the topical therapy with amikacin and ofloxacin.

Precision of genotyping of Epstein-Barr virus by polymerase chain reaction using three gene loci (EBNA-2, EBNA-3C, and EBER): predominance of type A virus associated with Hodgkin's disease

To precisely determine the genotype of Epstein-Barr virus (EBV) in Hodgkin's disease (HD), we simultaneously analyzed three divergent gene loci (EBNA-2, EBNA-3C, and EBER) that distinguish type A and B viruses. The primers designed to amplify these three gene loci encompass either type-specific deletion sequences (EBNA-2 and EBNA-3C) or type-specific point mutations (EBER) that identify the virus strain based on the sizes of the polymerase chain reaction (PCR)-amplified products or the mobility shifts in single-strand conformation polymorphism analysis. The locations of point mutations were identified by direct sequencing of the PCR-amplified DNA. We analyzed 15 EBV-infected cell lines and found a good correlation between EBNA-2 and EBNA-3C typing results. In contrast, approximately 33% of the cell lines analyzed maintained type A sequences in EBNA-2 and EBNA-3C genes while carrying type B sequences in the EBER region. Data obtained from analysis of cell lines served as a reference for studying HD samples. EBV DNA was detected in about 70% of HD. Among the EBV-positive samples, 56% were associated with type A virus, 13% with type B, and 31% with dual viral sequences. Thus, type A virus is predominant in HD. Based on the histology, the frequencies of EBV positivity were 83%, 71%, and 33% for mixed cellularity, nodular sclerosis, and lymphocyte predominance, respectively. The detection of high frequency of both type A and B sequences in HD may provide a lead in investigating the role of dual viral infection in EBV pathogenesis.

The experience to use a modified en bloc excision technique in vitrectomy for diabetic traction retinal detachment

Modified en bloc excision is a technique in which all posterior hyaloid is excised except the portions essential for membrane dissection. Then, bimanual dissection techniques allow excision of retained fibrovascular membrane "en bloc" with hyaloid. In a consecutive series of 16 eyes with diabetic traction retinal detachment treated with this technique, visual acuity of 5/200 or better was obtained in 11 (69%) of the cases, and complete macula reattachment was noted in 14 (87%) of 16 eyes. The final visual acuity was improved in 12 (75%) cases. While this surgical technique allows a higher rate of anatomic success and less postoperative morbidity, visual results remain limited by irreversible alteration in retinal function.

Parkinsonism as an initial manifestation of brain tumor

Parkinsonism secondary to neoplasm is uncommon. We report two patients with bilaterally symmetric parkinsonism as the initial presentation of their brain tumors. The first patient was a 71-year-old woman who presented with a gradual onset of bilateral resting tremor, bradykinesia and rigidity. Computerized tomography (CT) of the brain revealed a large parasagittal tumor in the left frontal lobe. The patient completely recovered from the parkinsonian symptoms after removal of the brain tumor. The second patient, a 74-year-old man with a history of renal cell carcinoma of the right kidney suffered from an insidious onset of bilateral bradykinesia, rigidity and gait difficulty. Cerebral metastasis was noted on the brain CT scan. Early recognition of intracranial tumor as the cause of parkinsonism is important for the management of this type of movement disorder. Moreover, brain CT scanning plays an important role in the differential diagnosis of patients with parkinsonian symptoms.