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Biomedical subjects

J Logemann

Publications and source records attributed to J Logemann.

16 recordsLinked to original sources
PubMed2003

An explanation for the association between specific language impairment and toxemia.

An association between specific language impairment (SLI) and toxemia has been detected in several studies. No clear explanation for this association has been identified to date. However, a number of potential explanations have been offered. These include: (1) toxemia causes fetal anoxia which leads to brain damage; (2) toxemia in the mother is an indication of maternal immune attack on the developing brain; (3) the association between toxemia and SLI is indirect and arises because both are consequences of a common but as yet unknown etiological factor. In this paper we present a fourth possible explanation for the association. That is, that both SLI and toxemia may be the consequence of low circulating levels of essential fatty acids. Evidence supporting this hypothesis is presented and four possible mechanisms underlying the association are discussed.

Brain↗
PubMed2001

Tissue/dose compensation to reduce toxicity from combined radiation and chemotherapy for advanced head and neck cancers.

This study was undertaken to quantify the reduction in normal tissue complications resulting from the aggressive management of advanced head and neck cancers (AHNCs) utilizing tissue/dose compensation (TDC). Thirty-nine patients with AHNC were treated on an intensive chemotherapy + radiation regimen. Eighteen of 39 patients were treated using TDC; the remaining 21 patients were radiated without TDC (NTDC). Acute and chronic toxicities, swallowing, speech function, and quality of life were assessed. The TDC group had a smaller radiation dose gradient across the entire treatment volume. Unscheduled treatment breaks were required in 11% of TDC patients as compared with 43% of the NTDC group (P = 0.04). The TDC group had fewer Grade 3 or 4 acute and chronic toxicities and lower SOMA scores. At 3 months posttreatment, patients in the TDC group had better oral intake, lower pharyngeal residue, and better oropharyngeal swallowing efficiency and were able to swallow more bolus types. Patients in the TDC group also had better articulation. Use of TDC resulted in reduced treatment-related interruptions, decreased acute and chronic toxicities, and better speech and swallowing functions. Techniques to improve radiation dose conformality around the target tissues while decreasing the radiation dose to the normal tissues should be an integral part of aggressive combined modality therapy.

Adult↗
PubMed1999

Failure of cricopharyngeal myotomy to improve dysphagia following head and neck cancer surgery.

OBJECTIVE: To determine whether cricopharyngeal myotomy can improve dysphagia associated with head and neck cancer surgery. DESIGN: Prospective, randomized, multicenter trial. SETTING: Twelve clinical sites across the United States. PATIENTS: Between 1989 and 1994, 125 patients undergoing combined modality therapy for head and neck cancer, including resection of the tongue base or supraglottic larynx, were prospectively entered into the trial. INTERVENTION: Cricopharyngeal myotomy on a randomized basis. MAIN OUTCOME MEASURES: Videofluoroscopic examination to determine oropharyngeal swallowing efficiency, which is defined as the ratio of percentage of the bolus swallowed to total swallowing time using 3 different bolus consistencies. RESULTS: No significant difference in oropharyngeal swallowing efficiency between myotomy vs no myotomy was seen at 6 months of follow-up regardless of bolus consistency. CONCLUSIONS: In this prospective test of cricopharyngeal myotomy, the procedure fails to significantly improve dysphagia associated with head and neck cancer surgery. The efficacy of this surgical procedure in other disease entities should also be rigorously explored.

Adult↗
PubMed1995

Enhanced quantitative resistance against fungal disease by combinatorial expression of different barley antifungal proteins in transgenic tobacco.

cDNAs encoding three proteins from barley (Hordeum vulgare), a class-II chitinase (CHI), a class-II beta-1,3-glucanase (GLU) and a Type-I ribosome-inactivating protein (RIP) were expressed in tobacco plants under the control of the CaMV 35S-promoter. High-level expression of the transferred genes was detected in the transgenic plants by Northern and Western blot analysis. The leader peptides in CHI and GLU led to accumulation of these proteins in the intercellular space of tobacco leaves. RIP, which is naturally deposited in the cytosol of barley endosperm cells, was expressed either in its original cytosolic form or fused to a plant secretion peptide (spRIP). Fungal infection assays revealed that expression of the individual genes in each case resulted in an increased protection against the soilborne fungal pathogen Rhizoctonia solani, which infects a range of plant species including tobacco. To create a situation similar to 'multi-gene' tolerance, which traditional breeding experience has shown to provide crops with a longer-lasting protection, several of these antifungal genes were combined and protection against fungal attack resulting from their co-expression in planta was evaluated. Transgenic tobacco lines were generated with tandemly arranged genes coding for RIP and CHI as well as GLU and CHI. The performance of tobacco plants co-expressing the barley transgenes GLU/CHI or CHI/RIP in a Rhizoctonia solani infection assay revealed significantly enhanced protection against fungal attack when compared with the protection levels obtained with corresponding isogenic lines expressing a single barley transgene to a similar level. The data indicate synergistic protective interaction of the co-expressed antifungal proteins in vivo.

Base Sequence↗
PubMed1994

Viscosity effects on EMG activity in normal swallow.

This study investigated the effects of six consistencies on measures of swallow duration, muscle activity, and sound. Electromyographic (EMG) recordings of the submental and infrahyoid muscle complexes, and audio recordings of neck sounds were made while 5 normal subjects swallowed two foods in each of three consistency categories: liquid, thin paste, and thick paste. Total swallow duration, measured from EMG, increased significantly across consistency categories from liquids to thin pastes to thick pastes. Liquids and thin pastes were significantly different from thick pastes on all but one EMG measure. However, liquids and thin pastes failed to reach significance on any of the EMG measures. EMG activity in the submental muscles most often initiated the swallow whereas the infrahyoid muscle activity most frequently terminated the swallow. A sound spike occurred at relatively the same time in each swallow. Results are discussed in terms of systematic modulations of muscle activity during swallow.

Adult↗
PubMed1989

Nucleotide sequence and regulated expression of a wound-inducible potato gene (wun1).

Mechanical wounding of potato leaves, stems, roots and tubers leads to a rapid increase of wun1 mRNA. In potato leaves, the wound-induced accumulation of wun1 mRNA is inhibited by the addition of sucrose or other osmotically active agents. This inhibition is organ specific since sucrose does not prevent wun1 mRNA accumulation in wounded tubers. In contrast, expression of patatin was shown to be repressed in tubers by wounding and this repression was reversed by increasing osmotic pressure. Sequence data obtained from the analysis of a wun1 cDNA and a wun1 genomic clone show no homology to any gene known so far. Histochemical data demonstrate a striking analogy in cell specific expression of chimeric genes expressed under the control of the wun1 promoter and the cell specific production of callose in wounded tobacco leaves.

Amino Acid Sequence↗
PubMed1989

5' upstream sequences from the wun1 gene are responsible for gene activation by wounding in transgenic plants.

A 1.2-kilobase pair fragment of the 5' upstream region of a potato wound-inducible gene (wun1) was fused to different marker genes (wun1-CAT, wun1-NPTII). Stable integration of a wun1-CAT chimeric gene into the tobacco genome led to a high wound-inducible chloramphenicol acetyltransferase activity in leaves. Transient expression experiments in potato protoplasts showed that wun1 carries a strong promoter sequence similar in strength to the 35S promoter. The same intensity of expression was also observed using wun1 constructs in transient experiments with rice protoplasts. wun1 mRNA was shown to accumulate to high levels in potato leaves collapsing as a result of infection with the phytopathogen Phytophthora infestans. The wun1 product might, therefore, play a role in a general physiological reaction to stress correlated with cell death.

Blotting, Northern↗
PubMed1989

cis-analysis of the wound-inducible promoter wun1 in transgenic tobacco plants and histochemical localization of its expression.

The 5' region of the wound-inducible gene wun1, derived from potato, has been sequenced and analyzed for cis-acting elements important in controlling gene expression in transgenic tobacco plants. Different 5' deletion fragments were linked to the reporter gene beta-glucuronidase (GUS) as transcriptional fusions, and the expression of these chimeric genes was analyzed in leaf tissue. Sequences 111 base pairs upstream of the transcriptional start site were not able to drive the GUS expression over background levels, whereas sequences between -111 and -571 showed a slightly higher activity with equal levels of transcription in wounded and nonwounded tissue. The addition of further upstream sequences (-571 to -1022) enhanced the level of expression by a factor between 13 and 370. The expression driven by this fragment was inducible by a factor of twofold to ninefold by wounding. Histochemical analysis of different tissue from transgenic plants that contain wun1-GUS fusions demonstrates wound-inducible and cell-specific wun1 promoter activity in plants containing the -1022-base pair fragment. The location of GUS activity appears to be cell-specific, being highest in epidermal cells of leaves and stems and lower in vascular cells. Activity was reduced to levels that could not be detected by histochemical staining in leaves, stems, and roots of plants containing the deleted promoter fragments. Plants that contain the different deletion constructs and plants that carry the -1022-base pair fragment show high expression in anthers and pollen grains that could not be stimulated by wounding.

Base Sequence↗
PubMed1988

Differential expression of genes in potato tubers after wounding.

Tubers of a common tetraploid species of Solanum tuberosum (Granola) were mechanically wounded by slicing. After 18 hr only small differences were detectable in the pattern of the steady-state protein extracted from wounded versus unwounded tubers. In contrast the protein pattern obtained by in vitro translation of mRNA isolated from wounded and unwounded tubers differed significantly. A cDNA library was established and screened for wound-induced cDNA clones by differential hybridization. Two clones, wun-1 and wun-2, were found that corresponded to genes that were highly expressed in wounded potato tubers but were not expressed in unwounded tubers. The expression of the gene corresponding to wun-1 is detectable 30 min after wounding; the expression of the gene corresponding to wun-2 is detectable 4 hr after wounding. The expression of both genes (hereafter referred to as wun-1 and wun-2) remains constant for up to 24 hr after wounding. Interestingly the RNA corresponding to patatin, a major storage protein of potato tubers, behaves in the opposite way; it decreases dramatically in tubers within 30 min after wounding. The low level of patatin mRNA observed in unwounded roots and stems also disappears after wounding. Run-off transcription experiments, performed with isolated nuclei, indicate that the activation of the wound-induced genes as well as the inhibition of the patatin gene are controlled at the transcriptional level.

Journal Article↗
PubMed1987

Improved method for the isolation of RNA from plant tissues.

A fast and efficient method for the isolation of RNA from plant tissues is described. Tuber tissue is homogenized in a guanidine hydrochloride-containing buffer followed by direct extraction with phenol/chloroform. The RNA is precipitated from the aqueous phase, washed with 3 M sodium acetate and 70% ethanol, and finally dissolved in water. The yield of RNA is up to 500 micrograms/g of tissue and several tests indicate intact and nondegraded RNA. This method can be adapted to a small-scale version by the use of 1.5-ml tubes, allowing rapid isolation of RNA from a larger number of samples. Finally, this method is of particular use for isolating RNA from tissues with a high polysaccharide and nuclease content such as wounded potato tubers.

Chloroform↗
PubMed1987

Effect of a maxillary glossectomy prosthesis on articulation and swallowing.

Swallowing was found to be substantially improved with the prosthesis. Less aspiration, less time necessary to complete the swallow, and greater variation in food consistency tolerated were all positive results of the prosthesis. In addition, videofluoroscopic studies of tongue movements during speech revealed that tip-alveolar /t-d/ and back-velar /k-g/ productions were more normal with the prosthesis. With the prosthesis, the understandibility of /t/ and /d/ was improved 20% and that of /k/ and /g/, 33%. It is clear that compromises must be effected in prosthesis design to facilitate improvement in both speech and swallowing. A large prosthetic mass in the oral cavity can also negatively change speech resonance. These issues are being investigated, as are acoustic and perceptual studies of speech articulation. Future research should address whether a combination of maxillary and mandibular prostheses would result in better speech and swallowing function. A mandibular prosthesis could replace missing teeth and alveolar contour that might influence speech and swallowing. A mandibular prosthesis might also allow construction of a smaller maxillary glossectomy prosthesis to interact with the mandibular prosthesis.

Articulation Disorders↗