PubMed Health⌕ Search

Biomedical subjects

M D Law

Publications and source records attributed to M D Law.

17 recordsLinked to original sources
PubMed1997

Nucleotide sequence and taxonomy of maize chlorotic dwarf virus within the family Sequiviridae.

The complete sequence of a Tennessee isolate of maize chlorotic dwarf virus (MCDV-TN) was determined from cDNA clones and by direct sequencing of the viral RNA. The genome is 11813 nucleotides (nt) in length and contains one large open reading frame between nt 435 and 10763 that encodes a polyprotein of 3443 amino acids. The N-terminal amino acid sequences were determined for the three capsid proteins. All three were adjacent, starting at nt 2526 and putatively ending at nt 3761. Comparison of the sequence of MCDV-TN with other viral sequences revealed similarities to several plant picorna-like viruses including members of the Sequiviridae, Comoviridae and Potyviridae. This work also provides evidence based on genome organization that MCDV-TN is a member of the genus Waikavirus within the family Sequiviridae.

Amino Acid Sequence↗
PubMed1994

De novo generation and accumulation of tomato bushy stunt virus defective interfering RNAs without serial host passage.

Studies were initiated to monitor generation and accumulation of defective interfering (DI) RNAs associated with tomato bushy stunt virus (TBSV) in the absence of serial, high multiplicity of infection passage. Infections were initiated in Nicotiana clevelandii host plants and protoplast cell suspensions by inoculation with in vitro-synthesized infectious TBSV RNA transcripts containing a genomic marker. The infections were then assayed for DI-size RNAs by both Northern blot analysis and reverse transcription coupled with PCR amplification. DI-size RNAs could not be detected by Northern blot analysis in either plants or protoplasts after an evident viral infection. However, RT-PCR amplification permitted the isolation of DI-size cDNAs (600-700 nt) from plant, but not protoplast, infections as early as 8 days postinoculation. Sequence analysis of these DI-size cDNA clones revealed that they contained the four conserved regions found in all previously identified competent DI RNAs. Several DI RNA clones contained the genomic marker which confirmed their de novo generation from the input transcript inoculum. A comparison of the nucleotide sequence of these clones to previously sequenced DI RNAs, isolated from plants after multiple passages, showed that differences existed at the junctions between regions. These results demonstrate that a heterogeneous population of DI RNAs accumulated in plants in the absence of serial host passage. In addition, the similarity of these DI RNAs to previously characterized DI RNAs that accumulate upon passage indicates that evolution can occur very rapidly within the initially inoculated plant.

Base Sequence↗
PubMed1994

Removal of broken syndesmotic screws: a technical tip.

A simple method of extracting broken distal tibial-fibular syndesmotic or cross-locking screws for intramedullary nails is illustrated. After extraction of the head portion of the broken screw, a blunt impactor is introduced through the vacant screw hole and abutted to the remaining portion of the screw tip. The screw can usually be impacted through the far cortex. A small incision should be made over the protruding portion, and the screw extracted with pliers.

Bone Screws↗
PubMed1993

Late infection in healed fractures after open reduction and internal fixation.

Nine patients with normal fracture healing after open reduction and internal fixation presented with late infection 15 months to 19 years after injury. Eight of the nine patients had a history of pain at the fracture site for 3 weeks or longer. Elevated temperature and white blood cell count were unreliable indicators of infection. Six patients had an elevated erythrocyte sedimentation rate that correlated with osteomyelitis. Roentgenograms showed resorption around the implant in seven patients and a small nidus in two patients. There was a change in position of fixation screws in four patients. Cigarette smoking and alcoholism were the most common systemic risk factors. Local risk factors were open fracture, lower-extremity site, distal femur site, and chronic edema of the lower extremities. Late infection should be included in the differential diagnosis of patients presenting with new-onset pain and a retained orthopaedic implant. Patients who fall into this group may be at increased risk for development of late hematogenous infection of orthopaedic implants.

Adult↗
PubMed1992

The M RNA of impatiens necrotic spot Tospovirus (Bunyaviridae) has an ambisense genomic organization.

The nucleotide sequence of Impatiens necrotic spot virus (INSV) M RNA was determined from cDNA clones. The INSV M RNA was 4972 nucleotides in length with two open reading frames (ORFs) in an ambisense genomic organization. The larger ORF near the 3' end of the viral RNA, coding for a protein with a predicted molecular weight of 124.9 kDa, was in the viral complementary sense and produced the G2 and G1 proteins. A smaller ORF in the viral sense was capable of coding for a 34.1-kDa polypeptide, designated the NSm protein. Two subgenomic RNA species were detected in INSV-infected tissue that corresponded to the predicted sizes (3.3 and 1.0 kb) of the G2-G1 and NSm mRNAs. The ORFs were separated by a 478 nucleotide A-U-rich intergenic region similar to the regions found in other viral RNAs with ambisense ORFs. The intergenic region was predicted to form a stable stem-loop structure (-81.2 kcal/mole). The ambisense genomic organization is characteristic of the S RNA for members of the Phlebovirus, Uukuvirus, and Tospovirus genera in the Bunyaviridae family. This is the first report of an ambisense Bunyaviridae M RNA.

Amino Acid Sequence↗
PubMed1991

Nucleotide sequence of the 3' non-coding region and N gene of the S RNA of a serologically distinct tospovirus.

A tomato spotted wilt-like virus (TSWV-I) is a distinct member of the Tospovirus genus of the Bunyaviridae and is distinguished from the typical TSWV by having a serologically distinct nucleoprotein (N). A cDNA clone extending from the 3' terminus of the viral RNA through the entire N open reading frame (ORF) was sequenced. The TSWV-I N ORF is capable of encoding a polypeptide of 262 amino acids with a predicted Mr of 28.8K. In vitro transcription and translation of the clone produced a protein which comigrated with TSWV-I N and was immunoprecipitated by TSWV-I antibodies. Hybridization analysis of lithium chloride-precipitated RNA from healthy and TSWV-I-infected tissue detected a virus-specific 1.2 kb subgenomic RNA. The TSWV-I S RNA terminal consensus sequence (8 nucleotides) was identical to that of TSWV; the remaining TSWV-I untranslated region showed only 51% identity with that of TSWV. Comparison of the TSWV-I and TSWV N proteins showed 67% identity at the amino acid level. The degree of similarity in the terminal sequence, untranslated region and N ORF is similar to that expected between distinct serogroups within certain genera of the Bunyaviridae.

Amino Acid Sequence↗
PubMedDate not supplied

Cervical spondylotic myelopathy: a review of surgical indications and decision making.

Cervical spondylotic myelopathy (CSM) is frequently underdiagnosed and undertreated. The key to the initial diagnosis is a careful neurologic examination. The physical findings may be subtle, thus a high index of suspicion is helpful. Poor prognostic indicators and, therefore, absolute indications for surgery are: 1. Progression of signs and symptoms. 2. Presence of myelopathy for six months or longer. 3. Compression ratio approaching 0.4 or transverse area of the spinal cord of 40 square millimeters or less. Improvement is unusual with nonoperative treatment and almost all patients progressively worsen. Surgical intervention is the most predictable way to prevent neurologic deterioration. The recommended decompression is anterior when there is anterior compression at one or two levels and no significant developmental narrowing of the canal. For compression at more than two levels, developmental narrowing of the canal, posterior compression, and ossification of the posterior longitudinal ligament, we recommend posterior decompression. In order for posterior decompression to be effective there must be lordosis of the cervical spine. If kyphosis is present, anterior decompression is needed. Kyphosis associated with a developmentally narrow canal or posterior compression may require combined anterior and posterior approaches. Fusion is required for instability.

Algorithms↗