Vascular decompression of a vertebral artery loop producing cervical radiculopathy. Case report.

Vertebral artery tortuosity and loop formation are rare causes of cervical radiculopathy. The authors present the case of a 70-year-old man with 9 years of progressive right-sided cervical and scapular pain but no history of trauma. Computerized tomography myelography and magnetic resonance imaging revealed an ovoid mass in the right C3-4 intervertebral foramen. The patient underwent a right C-3 and C-4 hemilaminectomy and a complete C3-4 facetectomy. A pulsatile vascular structure was found compressing the right C-4 nerve root. The bone overlying the vascular structure was removed, producing decompression of the nerve root. Immediate postoperative angiography showed that this lesion was a focal vertebral artery loop. The patient's symptoms resolved after surgery, supporting the use of vascular decompression of a cervical nerve root compressed by a vertebral artery loop for the relief of radicular symptoms.

Impact of traumatic subarachnoid hemorrhage on outcome in nonpenetrating head injury. Part II: Relationship to clinical course and outcome variables during acute hospitalization.

Patients with a nonpenetrating head injury and traumatic subarachnoid hemorrhage (tSAH) on admission head computed tomography scan (n = 240) were compared with patients without tSAH matched in terms of admission postresuscitation Glasgow Coma Scale (GCS) values, age, sex, and the presence of one or more types of intracranial mass lesions. Admission Injury Severity Score was higher only in tSAH patients with admission GCS scores between 13 and 15; GCS values at 6, 24, and 48 hours were lower for tSAH patients. Patients with tSAH underwent fewer craniotomies, but more than twice as many tSAH patients had high intracranial pressure at the time of ventriculostomy placement and 6 hours after admission. tSAH patients underwent more chest procedures and their incidence of hypoxia and hypotension was greater. tSAH patients spent more days in intensive care unit, more total days hospitalized, and had worse Glasgow Outcome Scale scores at acute hospital discharge. Fewer tSAH patients were discharged home, and almost 1.5 times as many tSAH patients died during hospitalization. Given a similar overall degree of injury at admission, patients with tSAH associated with a nonpenetrating head injury had a worse outcome than similar patients without tSAH.

Impact of traumatic subarachnoid hemorrhage on outcome in nonpenetrating head injury. Part I: A proposed computerized tomography grading scale.

The presence of traumatic subarachnoid hemorrhage (tSAH) on admission computerized tomography (CT) scans obtained from patients suffering from severe, nonpenetrating head injury has been shown to be associated with a worse outcome than the injury alone would warrant. However, no previous study has provided a simple means of relating the amount of tSAH, its location, or other abnormal findings on initial head CT scans to outcome in patients with non-penetrating head injury. In this study, admission head CT scans from 252 patients with tSAH, treated at a single institution, were reviewed to ascertain thickness of the tSAH; its location; evidence of mass lesion(s); shift of midline structures (< or = 5 mm vs. > 5 mm); basal cistern effacement; and cortical sulcal effacement. The CT scans were then organized into Grades 1 to 4 with 1 indicating thin tSAH (< or = 5 mm); 2, thick tSAH (> 5 mm); 3, thin tSAH with mass lesion(s); and 4, thick tSAH with mass lesion(s). A stepwise regression analysis of CT features ranked them in descending order of contribution to Glasgow Outcome Scale (GOS) scores at the time of discharge from acute hospitalization as follows: basal cistern effacement, thickness of tSAH, cortical sulcal effacement, presence of mass lesion(s), and location of tSAH. A shift of midline structures was not found to be a significant variable. Further analysis comparing CT grades and admission postresuscitation Glasgow Coma Scale (GCS) scores was highly significant. Patients with lower CT grades had better admission GCS values and discharge GOS scores than those with higher CT grades. From their experience, the authors conclude that their CT grading scale is simple and reliable and relates significantly to outcome at the time of discharge from acute hospitalization.

An essential gene in Saccharomyces cerevisiae shares an upstream regulatory element with PRP4.

ORF2 is an essential gene immediately upstream of PRP4 (formerly RNA4), a gene involved in nuclear mRNA processing in Saccharomyces cerevisiae. The two genes are arranged head-to-head. An 8 base-pair conserved sequence element is found upstream of both genes, as well as upstream of certain other genes that are known to be involved in pre-mRNA processing. Through deletion analysis we have found that both of the conserved sequence elements are important for transcription of both genes. We have cloned ORF2 and have isolated temperature-sensitive orf2 mutants. The phenotype of these mutants does not suggest a role for ORF2 in mRNA processing. The deduced amino acid sequence of ORF2 indicates significant similarity to DPR1, a gene encoding a protein that is involved in the carboxy-terminal processing of G-protein.

Molecular cloning of the phosphoenolpyruvate carboxylase gene of Anabaena variabilis.

Purified Anabaena variabilis chromosomal DNA was partially digested with restriction endonuclease Sau3A and ligated into the BamHI site of plasmid pBR322. Escherichia coli 342-167, a mutant with a decreased level of phosphoenolpyruvate carboxylase (PEPCase) activity was transformed with plasmids from the A. variabilis genomic library. A transformant that grew on minimal media in the absence of glutamate was isolated and its plasmid, pTRH1, was shown to encode the A. variabilis PEPCase. E. coli HB101 cells transformed with plasmid pTRH1 have approx. 50 times the normal amount of PEPCase activity and also overproduce a protein with the apparent Mr (99,000) of the A. variabilis PEPCase.

Solvent interactions with test compounds and recommendations for testing to avoid artifacts.

Reports in the literature describing artifactual results owing to interactions of test materials with solvents are becoming more frequent. The present study was initiated to examine possible interactions of 1,1,3-trichloro-, 1,1,3,3-tetrachloro-, pentachloro- and hexachloroacetones with different solvents, since certain solvent effects with the last compound have been shown previously. Quantitative differences in levels of mutagenic potency were found for tri-, tetra-, and pentachloroacetone, dissolved in acetone or dimethyl sulfoxide (DMSO). On the other hand, hexachloroacetone without solvent was mutagenic, and this activity was enhanced when it was dissolved in DMSO; in acetone it was not mutagenic. A time-dependent reaction of hexachloroacetone with DMSO was the only test material-solvent interaction found in this study. The results show clearly that DMSO is not an appropriate solvent for hexachloroacetone. On the basis of these and previous results, we recommend consideration of the following strategy to help prevent reporting of artifactual results owing to interaction with solvents: Results from initial screening experiments should be confirmed in repeat experiments using a different solvent; and a different solvent should be used in confirming the findings of other investigators. Differences in results would indicate a need for further study.

Mutagenicity in a modified Salmonella assay of fabric-protecting products containing 1,1,1-trichloroethane.

Methyl chloroform (1,1,1-trichloroethane) was identified as a major component in two fabric-protector spray products. Mutagenic effects were determined at several dosage levels for the two products and some of the identified components. Levels of organics in the air of sealed desiccators, used as exposure chambers in modified Salmonella reversion assays, were measured by a gas chromatographic technique. Both fabric protectors and two samples of trichloroethane were mutagenic in strain TA 1535 and one of each was mutagenic in strain TA 100. Other constituents, such as petroleum distillate and p-dioxane, were nonmutagenic at the tested exposure levels.

Genotoxic activity of pulp mill effluent in Salmonella and Saccharomyces cerevisiae assays.

An XAD-2 resin concentrate of chlorination-stage pulp mill effluent was found to induce mutations in Salmonella typhimurium strains TA1535, TA100 and TA98 but not in strains TA1537 or TA1538. The presence of either S9 mix, S9 mix without cofactors, or heat-inactivated S9 mix, reduced the mutagenic effects. Dose-related increases in gene conversion, mitotic recombination and aberrant colony formation in Saccharomyces cerevisiae strain D7 also were found.

Suitability of the modified fluctuation assay for evaluating the mutagenicity of unconcentrated drinking water.

Filter-sterilized, unconcentrated tap water induced mutagenic responses (p less than 0.01) in Salmonella strain TA100 in fluctuation assays, usually with dose-related increases in positive tubes. Additional experiments were performed to study possible artifacts that could lead to falsely positive results. Determinations of bacterial survival revealed that cell populations in the tubes containing tap water were larger than in the controls. Since spontaneous mutation is a function of cell generation, the increased numbers of bacteria appeared to be responsible for the higher numbers of mutants observed. Therefore, the positive responses must be regarded as artifactual. This study suggests that survival determination should be a routine part of this method, and care should be exercised in the interpretation of positive results.

A comparison of the anatomical uniformity of irradiation in two different photochemotherapy units.

Measurements have been made of the anatomical distribution of ultraviolet radiation resulting from the irradiation of an inanimate manikin in a PUVA 6000 unit and a PUVA 4000 unit. The dosimeter used was phenothiazine film. The results indicated a very similar pattern of relative UV dose on the surface of the manikin from both units.

A dosimeter for long wave ultraviolet radiation.

A polymer film, which incorporates phenothiazine as the chromophore, has been developed as a personnel dosimeter for long wave ultraviolet radiation. It is stable, reproducible and is particularly suited to monitoring the doses received by patients undergoing photochemotherapy for psoriasis.