Autosomal dominant retinitis pigmentosa: four new mutations in rhodopsin, one of them in the retinal attachment site

Several mutations in the rhodopsin gene in patients affected by autosomal dominant retinitis pigmentosa (ADRP) have recently been described. We report four new rhodopsin mutations in ADRP families, initially identified as hetero-duplexed PCR fragments on hydrolink gels. One is an in-frame 12-bp deletion of codons 68 to 71. The other three are point mutations involving codons 190, 211, and 296. Each alters the amino acid encoded. The codon 190 mutation has been detected in 2 from a panel of 34 ADRP families, while the remaining mutations were seen in single families. This suggests that, consistent with a dominant condition, no single mutation will account for a large fraction of ADRP cases. The base substitution in codon 296 alters the lysine residue that functions as the attachment site for 11-cis-retinal, mutating it to glutamic acid. This mutation occurs in a family with an unusually severe phenotype, resulting in early onset of disease and cataracts in the third or fourth decade of life. This result demonstrates a correlation between the location of the mutation and the severity of phenotype in rhodopsin RP.

Epstein-Barr viral genome in lymph nodes from patients with Hodgkin's disease may not be specific to Reed-Sternberg cells

A possible etiologic role for Epstein-Barr virus (EBV) in Hodgkin's disease (HD) was investigated by probing for EBV genome in 52 biopsy specimens involved with HD and 43 hyperplastic lymph node specimens. Using dot-blot hybridization (Bam HIW probe), Southern blot hybridization (Xho I probe), and polymerase chain reaction analyses, 27%, 27%, and 58% of the nodes with HD were positive for EBV genome, respectively, as compared to 16%, 14%, and 43% in the hyperplastic lymph nodes. Clonal and nonclonal episomal EBV and linear replicating EBV genome were present in both conditions. Immunoglobulin heavy chain gene rearrangements were found in two clonal and two nonclonal EBV-positive HD cases, but not in the lymphoid hyperplasia cases. These findings and other recent reports showing EBV genome in benign lymphoid cells by in situ hybridization in Hodgkin's disease suggest that the characteristics of EBV infection in HD could be explained by the reactive cellular milieu, especially in the setting of defective immunity. The identification of EBV genome in Reed-Sternberg cells may, therefore, be a nonspecific phenomenon.

A 3-bp deletion in the rhodopsin gene in a family with autosomal dominant retinitis pigmentosa

Autosomal dominant retinitis pigmentosa (ADRP) has recently been linked to locus D3S47 (probe C17), with no recombination, in a single large Irish family. Other ADRP pedigrees have shown linkage at zero recombination, linkage with recombination, and no linkage, demonstrating genetic heterogeneity. The gene encoding rhodopsin, the rod photoreceptor pigment, is closely linked to locus D3S47 on chromosome 3q. A point mutation changing a conserved proline to histidine in the 23d codon of the gene has been demonstrated in affected members of one ADRP family and in 17 of 148 unrelated ADRP patients. We have sequenced the rhodopsin gene in a C17-linked ADRP family and have identified in the 4th exon and in-frame 3-bp deletion which deletes one of the two isoleucine monomers at codons 255 and 256. This mutation was not found in 30 other unrelated ADRP families. The deletion has arisen in the sequence TCATCATCAT, deleting one of a run of three x 3-bp repeats. The mechanism by which this occurred may be similar to that which creates length variation in so-called mini- and microsatellites. Thus ADRP is an extremely heterogeneous disorder which can result from a range of defects in rhodopsin and which can have a locus or loci elsewhere in the genome.

Autosomal dominant retinitis pigmentosa: absence of the rhodopsin proline----histidine substitution (codon 23) in pedigrees from Europe

In exon 1 at codon 23 of the rhodopsin gene, a mutation resulting in a proline-to-histidine substitution has previously been observed in approximately 12% of American autosomal dominant retinitis pigmentosa (ADRP) patients. The region around the site of this mutation in the rhodopsin gene has been amplified and analyzed in affected individuals from 91 European ADRP pedigrees. The codon 23 mutation has been found to be absent in all cases, including a large Irish pedigree in which the disease gene has previously been shown to be closely linked to the rhodopsin locus. This indicates the presence of either allelic or nonallelic heterogeneity in ADRP.

Linkage to D3S47 (C17) in one large autosomal dominant retinitis pigmentosa family and exclusion in another: confirmation of genetic heterogeneity

Recently Dryja and his co-workers observed a mutation in the 23d codon of the rhodopsin gene in a proportion of autosomal dominant retinitis pigmentosa (ADRP) patients. Linkage analysis with a rhodopsin-linked probe C17 (D3S47) was carried out in two large British ADRP families, one with diffuse-type (D-type) RP and the other with regional-type (R-type) RP. Significantly positive lod scores (lod score maximum [Zmax] = +5.58 at recombination fraction [theta] = .0) were obtained between C17 and our D-type ADRP family showing complete penetrance. Sequence and oligonucleotide analysis has, however, shown that no point mutation at the 23d codon exists in affected individuals in our complete-penetrance pedigree, indicating that another rhodopsin mutation is probably responsible for ADRP in this family. Significantly negative lod scores (Z less than -2 at theta = .045) were, however, obtained between C17 and our R-type family which showed incomplete penetrance. Previous results presented by this laboratory also showed no linkage between C17 and another large British R-type ADRP family with incomplete penetrance. This confirms genetic heterogeneity. Some types of ADRP are being caused by different mutations in the rhodopsin locus (3q21-24) or another tightly linked gene in this region, while other types of ADRP are the result of mutations elsewhere in the genome.

No evidence for linkage between late onset autosomal dominant retinitis pigmentosa and chromosome 3 locus D3S47 (C17): evidence for genetic heterogeneity

Retinitis pigmentosa is an inherited form of blindness caused by progressive retinal degeneration. P. McWilliam et al. (1989, Genomics 5: 619-622) demonstrated close genetic linkage between autosomal dominant retinitis pigmentosa (ADRP) and locus D3S47 (C17) in a single early onset pedigree. The marker C17 maps to the long arm of chromosome 3. Clinically, the disease phenotype has been subdivided into at least two forms on the basis of age of onset, as well as electrodiagnostic criteria. We demonstrate that C17 is unlinked in a late onset pedigree, indicating that the phenotypic variation seen reflects underlying genetic heterogeneity.

Detection of Epstein-Barr virus by in situ hybridization. Progress toward development of a nonisotopic diagnostic test

This work presents some initial quantitation of an in situ hybridization method for detection of Epstein-Barr (EB) virus nucleic acids. The purpose is to develop evaluative criteria for diagnosis of viral presence in clinical tissue specimens. In this work simultaneous denaturation of probe and target DNA and an alkaline phosphatase conjugate to detect biotinated probe were used as described by Unger et al. For evaluation of the hybridization, a variety of cell lines, both productively and latently infected, that were hybridized in situ using nick translated 32P-labeled viral probe sequences and counted by scintillation after the method of Lawrence and Singer were used. Producer cells (B95-8) showed intense foci of staining in approximately 5% of cells, with most of the other cells showing varying staining intensity. Raji cells showed varying amounts of signal from cell to cell. Namalwa cells exhibited one spot in most cells that was decreased after cells were treated with Actinomycin D (dactinomycin, Merck Sharp & Dohme, West Point, PA). Signal was identified in only a third of these same cells after sectioning. EB virus-negative Ramos cells showed no signal. The nuclear punctate nature of the signal generated is diagnostic of infected cells, and may be a useful test for cultured cells or pathologic specimens.

Immunophenotypic profile of CNS lymphoma: a review of eighteen cases

The cell surface antigenic phenotype of 18 cases of central nervous system (CNS) large-cell lymphoma (14 primary, four secondary) was examined by an immunoperoxidase technique using antibodies that identify B cell restricted and associated antigens. All cases were shown to be of B cell origin by virtue of the expression of monotypic immunoglobulin (Ig) (16 IgM, two IgG) and the pan B cell antigen B1 (CD20). A panel of monoclonal antibodies directed against B cell restricted and associated activation antigens including B5, Blast-1, Blast-2 (CD23), BB1, interleukin 2 receptor (IL2R, CD25), T9 (transferrin receptor) and TNK-TAR (4F2) was used on 12 of the cases. The majority expressed T9 and TNK-TAR. Blast-1 was expressed by less than half the cases and Blast-2 and B5 by one of 12 cases each. This is in contrast to 10 non-CNS diffuse large cell lymphomas where B5 and Blast-1 were present on all cases. This study confirms previous observations that primary CNS large cell lymphomas are of B cell derivation. Moreover, the differences in expression of B cell activation antigens on CNS large cell lymphomas as compared to non-CNS lymphomas raise the possibility that a subset of neoplastic B cells may have unique tropism for the CNS.

High-dose methotrexate for non-AIDS primary central nervous system lymphoma. Report of 13 cases

Thirteen patients with primary lymphoma of the central nervous system (CNS) were treated with high-dose intravenous methotrexate (MTX), 3.5 gm/sq m, followed by calcium leucovorin rescue, at 3-week intervals, for three cycles. Eleven patients subsequently received radiation therapy to the whole brain, 30 to 44 Gy. Before radiation therapy, eight patients responded completely and four partially; there was one non-responder. The median Karnofsky score before high-dose MTX therapy was 60 and increased to 90 after treatment. Five of the eight complete responders reached a Karnofsky rating of 100. The three longest responders (one of whom received MTX only) were without recurrence of their disease at 29+, 32, and 32+ months posttherapy. The median response period is 9+ months. The median survival time from the date of the first MTX treatment is 9+ months, and the three longest survival times are 29+, 32+, and 54+ months. All patients received corticosteroids in either unchanging or diminishing dosages during therapy. It is concluded that primary CNS lymphoma is sensitive to high-dose MTX, which provides a safe and easily administered adjuvant to radiation therapy for this neoplasm.

Regrowth patterns of glioblastoma multiforme related to planning of interstitial brachytherapy radiation fields

Recognition of the local nature of glioblastoma has generated an increasing interest in treatment using radioactive implants (interstitial brachytherapy). A key issue in such implantation is the configuration of the radiation field in relation to the resected tumor. In particular, should radiation be provided to the area from which the tumor has been resected? To clarify this issue, we evaluated patterns of tumor regrowth into this resected area in 62 patients. Three patterns of computed tomographic scan-documented tumor regrowth were recognized: preferential (regrowth to refill the resected area only), circumferential (regrowth into the resected area and previously uninvolved contiguous brain) and away (local regrowth into noncontiguous brain, sparing the surgical bed). Regrowth of the tumor 6.3 to 6.8 months after resection was seen in 59 of 62 patients (95.2%). Preferential regrowth was seen in 32 of 62 patients (51.6%), and circumferential regrowth was seen in 27 of 62 patients (43.5%). Regrowth away was seen in 3 of 62 patients (4.8%). Radiation fields planned for interstitial brachytherapy must adequately include the resected area because of the high incidence of tumor regrowth into that area.

Pre-irradiation internal carotid artery BCNU in treatment of glioblastoma multiforme

High-dose 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) infusion into the internal carotid artery following cranial irradiation in the treatment of glioblastoma multiforme is accompanied by evidence of leukoencephalopathy in a significant number of patients. In an attempt to avoid this problem, a phase I trial was performed using intracarotid BCNU infusion before irradiation. Twenty-eight patients with grade III/III astrocytoma (World Health Organization Classification, equivalent to Kernohan grade IV) received a 400-mg infusion of BCNU into the infraophthalmic carotid artery. The treatment was repeated every 4 weeks for a total of four cycles prior to cranial irradiation (5500 to 6000 cGy). The major toxic sequelae included nausea and vomiting (24%), decreased visual acuity (14%), transient cerebral ischemia (3.5%), and thrombocytopenia (3.5%). Fatal leukoencephalopathy occurred in two patients. The median survival time was 37 weeks for all evaluable patients and 56+ weeks for those completing the protocol. The tumor response to drug infusion as judged by computerized tomography (CT) was complete in 22% of patients and partial in 22%; 56% showed no CT tumor response. Pre-irradiation intracarotid artery BCNU benefits a very small group of patients with grade III/III astrocytoma. The associated severe leukoencephalopathy makes this mode of therapy unacceptable for a phase III trial.

Dynamic computed tomography of cerebral parenchymal tuberculomata

The technique of intravenous dynamic cranial computed tomography has been applied to our patient population in Saudi Arabia in which parenchymal tuberculomata make up approximately 10-15% of all cerebral mass lesions. A spectrum of perfusion patterns was observed in tuberculosis progressing from presentation, through treatment, to resolution. These patterns reflect the microscopic vascular evolution of tuberculomata and parallel at least in part the effects of treatment. The method of dynamic scanning further demonstrates its value in improving the specificity of computed tomography in the evaluation of cerebral masses, thereby enhancing patient-beneficial triage.

The multiple manifestations of the encephalocraniocutaneous lipomatosis syndrome

A case is reported of a recently described neurocutaneous syndrome, manifested by a noncommunicating right lateral ventricular cyst, a left-sided lipoma of the scalp with alopecia, right-sided multiple truncal lipomas, right-sided ocular manifestations, left leg hypertrophy, and seizures. The findings in cases of encephalocraniocutaneous lipomatosis are described to demonstrate the spectrum of this syndrome.

The parenchymal CT myelogram: in vivo imaging of the gray matter of the spinal cord

Past attempts to visualize the internal structure of the spinal cord in vivo have been hampered by many factors, including the small size of the cord, the dense bony investiture of the spine, and the similarities of tissue densities from one region to another within the cord. Delayed CT is the imaging technique currently being used at our institution as an adjunct to iopamidol myelography to visualize the deep gray matter of the cord. This visualization is achieved by a poorly understood differential gray/white-matter enhancement, possibly due to either a shielding effect of the white matter as it envelops the gray matter, a differential absorption rate between gray and white matter, or a greater rate of reabsorption of contrast by the more highly vascularized gray matter. This method is not being advocated as a primary diagnostic technique due to the lack of reliability in providing successful results from section to section, from patient to patient, and from one time period of delay to the next. Instead, it is an initial attempt to image the basic, intrinsic structure of the spinal cord in vivo, which may herald a valuable advance in imaging methodology.

Cystic necrosis of the spinal cord in compressive cervical myelopathy: demonstration by iopamidol CT-myelography

Seven consecutive patients with compressive cervical myelopathy were studied with standard water-soluble contrast myelography and immediate CT followed by delayed CT of the spinal canal at 10 to 12 hr. Every case demonstrated findings suggestive of necrosis and/or cavitation of the central portions of the spinal cord on the delayed CT study. Two types of abnormalities were visualized in the form of delayed collections of contrast media inside the cord: bilateral enhancement, a double-barreled "snake-eyes" appearance at or near the level of compression (consistent with central gray matter necrosis and/or cavitation--local syringomyelia ex-vacuo); and longitudinally oriented, "pencil-shaped" central enhancement of variable length distant from the level of compression (consistent either with an enlarged central canal--hydromyelia ex-vacuo--or with necrosis and/or cavitation extending craniad and caudad from the area of maximal compression and located in or near the anterior portion of the dorsal columns--distant syringomyelia ex-vacuo). These findings, supported by previous reports of autopsy specimens, may explain in part: the frequent discrepancy between the levels of maximal cervical compression and the variable neurologic signs; and the frequent lack of improvement in clinical signs after surgical decompression of the spinal cord at this late stage of the illness. We believe similar intramedullary lesions may be present in other cases of chronic compression of varying etiology at any location within the spinal cord.

Nervous system brucellosis: diagnosis and treatment

We treated six patients with nervous system brucellosis causing polyradiculitis (2 patients), myelopathy (2), encephalitis (1), or meningitis (1). Diagnosis was based on Brucella species cultured from one patient, and a twofold or greater rise in antibody titer after therapy was started in the others. Treatment with trimethoprim-sulfamethoxazole with rifampin (5 patients) or tetracycline (1 patient) produced excellent clinical and laboratory response.

Syrinx of the conus medullaris and filum terminale in association with multiple hemangioblastomas

A patient with multiple hemangioblastomas and syrinxes of the cerebellum and spinal cord is presented. An additional mass imaged at the L-3 vertebral level was identified by percutaneous syringography as a bilobular syrinx extending from the conus medullaris into the filum terminale. At surgery the syrinx was opened into the caudal cerebrospinal fluid space and the several hemangioblastomas excised. These spinal tumors all appeared to arise in juxtaposition to the posterolateral sulcus and dorsal sensory roots.

Cerebral infarction in a young female following snake bite

We present a normal 13-year old female who developed left cerebral infarction following envenomation by the carpet viper (Echis carinatus). We have read of only one other case of cerebral infarction following viper envenomation (Viperi russelli). Possible mechanisms for cerebral infarction in these circumstances are discussed. It is believed that this complication may be more common than is reported in the literature.

Temporal appearance and distribution of the Ca2+ + Mg2+ ATPase of the sarcoplasmic reticulum in developing chick myocardium as determined by immunofluorescence labeling

The temporal appearance and distribution of the Ca2+ + Mg2+ ATPase of the sarcoplasmic reticulum were determined in the developing chick heart (stage 9 to stage 16) by indirect immunofluorescence labeling. The results obtained showed that the Ca2+ + Mg2+ ATPase was first observed in the bulbus ventricular region of the single tubular heart at stage 9 to 10 of development, when these myocardial cells first contract. As the atrial and later the sinus venosus tissues became incorporated into the single tubular heart the Ca2+ + Mg2+ ATPase was also observed in these regions, however, the highest density of Ca2+ + Mg2+ ATPase labeling was generally observed in the region of the heart most recently incorporated. These results suggest that the sarcoplasmic reticulum is present and perhaps functional in the regulation of the cytoplasmic Ca2+ concentration and thereby the contraction-relaxation cycle in myocardial cells when the first contraction occurs, as well as throughout all subsequent stages of development. Furthermore comparison between the relative density and intensity of the Ca2+ + Mg2+ ATPase labeling and the intrinsic rate of contraction of the myocardial cells in the various regions of the heart (A. Barry, 1942, J. Exp. Zool. 91, 119-130) supports the possibility that a positive correlation exists between these two characteristics of the myocardial cells.