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Biomedical subjects

M Collins

Publications and source records attributed to M Collins.

At least 325 records · Page 18Linked to original sources
PubMed1983

Spectrographic analysis of vowel and word duration in apraxia of speech.

Most normal speakers of English reduce the duration of the stem word vowel as words increase in length. Theoretically, this durational reduction reflects low-level linguistic knowledge. We posed two questions in this study: First, do speakers with apraxia of speech progressively reduce vowel durations as words increase in length, and second, do these vowel and word durations differ significantly from normal productions? We asked 11 apraxia of speech patients and 11 normal speakers to repeat three sets of three words which progressively increased in length, and we analyzed these productions spectrographically. Our results revealed that both groups reduced vowel duration as words increased in length. Word and vowel duration for apraxia of speech patients, however, were often significantly longer than those for normal speakers. Our results suggest that vowel reduction is a robust phenomenon which resists impairment in apraxia of speech, despite often significant disturbances in motor programming.

Adult↗
PubMed1983

Limitations of available tests for diagnosis of infectious mononucleosis.

Among 500 students seen at a university health service for illnesses resembling infectious mononucleosis (IM), the diagnosis of IM was established in 124 (25%) on the basis of the initial presence or subsequent emergence of the spectrum of Epstein-Barr virus (EBV) antibodies characteristic of a primary EBV infection. Of these 124 patients, 113 had an EBV-specific antibody pattern in the initial serum indicative of current primary infection; however, 11 (9%) had no detectable immunoglobulin G antibodies to EBV-specific antigens in their first serum. The sensitivity of this panel of EBV antibody assays was 91% and the specificity was 100%. Initial sera had detectable heterophil antibodies for 107 (86%) of the 124 students with IM and for 2 with other illnesses. Among our patients, the Monospot (Ortho Diagnostics Inc.) test had a sensitivity of 86% and a specificity of 99%. Reliance on hematological criteria (lymphocyte count greater than or equal to 50% and atypical lymphocyte count greater than or equal to 10%) gave a sensitivity of only 39%, but a specificity of 99%. Students with IM who showed a delayed emergence of the spectrum of EBV-specific antibodies characteristic of an acute infection were compared with control patients who had such antibodies at the time of their initial visit to the health service. They were found to have a briefer duration of illness (P greater than 0.05), lower leukocyte (P less than 0.005), lymphocyte (P less than 0.005), and atypical lymphocyte (P less than 0.05) counts, and a less frequent occurrence of heterophil antibodies (P less than 0.05).

Antibodies, Viral↗
PubMed1983

An objective feature extraction technique applied to the Doppler waveforms from the groin: a prospective study.

A group of 80 patients presenting with lower limb ischaemia were classified according to their arteriographic findings. The maximum frequency envelope from the Doppler waveforms obtained from the common femoral artery were retrospectively analysed using a mathematical feature extraction technique, principal component analysis (PCA). Two of the three coefficients uniquely describing each waveform were plotted and classified according to their arteriographic groupings. The best separating planes were then defined. Twenty-eight new patients were subsequently prospectively assessed using the principal components and separating planes defined in the previous study. The results were compared with the arteriographic findings and showed that PCA represents a significant improvement in diagnostic accuracy when compared with other techniques.

Aorta↗
PubMed1983

Paralysis in nude mice caused by polyomavirus-induced vertebral tumors.

Eighty-one of 95 BaLB/c nude mice infected intracranially with the LID strain of polyomavirus developed tumors of the vertebrae which compressed the spinal cord or peripheral nerves and produced paralysis. Wallerian degeneration was the only pathological alteration found in the nervous system of polyoma-infected mice. While polyomavirus was demonstrated in the brain and spinal cord by viral isolation and immunoperoxidase staining, no evidence of a primary demyelinating process was found. The disease produced in the present study is not a satisfactory animal model of progressive multifocal leukoencephalopathy.

Animals↗
PubMed1983

Effects of subacute low level lead exposure on glucose homeostasis.

Administration of low levels of lead (0.001, 0.005 and 0.025 micrograms/g/day p.o.) to neonate rats from age three days to eight weeks failed to alter the activities of hepatic glucose-6-phosphatase, fructose-1,6-diphosphatase, pyruvate carboxylase and phosphoenolpyruvate carboxykinase, the four key gluconeogenic enzymes. Administration of lead at a higher dose (0.1 micrograms/g/day p.o.) was also observed to produce no alterations in enzyme activity at eight weeks. However, the higher dose did enhance the activities of fructose-1,6-diphosphatase and phosphoenolpyruvate carboxykinase at age six weeks. Plasma insulin and glucagon were not significantly altered by up to 0.025 micrograms/g exposure to lead until eight weeks of age, although levels of these hormones appear to be slightly dose-responsive tending towards elevated glucagon and decreased insulin levels with increasing lead dosage. At 0.1 micrograms/g/day glucagon was significantly increased at eight weeks. Blood glucose and hepatic glycogen remained unaltered. Blood, hepatic and pancreatic lead levels were unchanged by treatment with lead up to 0.025 micrograms/g/day to eight weeks of age, but there was evidence of lead accumulation in pancreatic tissue whereas levels of the metal in the liver paralleled those in the blood. Significant increases were observed with 0.1 micrograms/g/day lead at six and eight weeks in blood and pancreas. Data are presented which suggest that six week old animals are more influenced by subacute lead exposure than are the eight week old animals, as reflected in some alteration of gluconeogenic enzyme activity in younger rats.

Animals↗
PubMed1983

Dermatologic practice: implications for a primary care residency curriculum.

The problems encountered, diagnostic procedures performed, and treatments prescribed in dermatology were studied in a primary care practice and in a dermatology clinic. Referrals from a primary care practice to a dermatology practice were analyzed. It was determined that nine disease categories accounted for more than 75 percent of the problems encountered in both settings. Only one diagnostic procedure was performed commonly in both the primary care and dermatology practices--skin scraping for fungal infection. Approximately 90 percent of the treatments prescribed in both settings fell within 13 categories. It is proposed that these findings be the basis for designing the curriculum in dermatology for residents in primary care medicine. The curriculum also should provide practical experience in dermatology and familiarity with selected, rarely encountered dermatologic conditions that have important therapeutic implications.

Boston↗
PubMed1983

Evaluation of neurotoxicity after subarachnoid injection of large volumes of local anesthetic solutions.

Recent case reports describing prolonged neurologic deficit after accidental spinal anesthesia with large volumes of 2-chloroprocaine have led to the suggestion that chloroprocaine may be more likely to cause such complications than other local anesthetics. We evaluated the neurologic effects of lumbar puncture alone and of large-volume subarachnoid administration of 2-chloroprocaine (3%), bupivacaine (0.75%), lidocaine (2%), Elliott's solution B (which is similar to CSF), or the carrier solution of 2-chloroprocaine (Nesacaine) in 48 sheep and 8 monkeys. Cerebrospinal fluid of sheep was collected on days 1 and 7 for biochemical and biological analyses, and CSF pressures of monkeys were recorded before and after injection. Animals were observed for neurologic deficits for seven days. Twelve sheep were unable to stand. Monkeys, on the other hand, had no apparent neurologic deficits. Autopsies revealed that 5 of the 12 sheep had lumbar subpial demyelination with macrophage infiltration: two of the five had received lidocaine; two received 2-chloroprocaine; and one had only a lumbar puncture. Two other sheep also had subpial demyelination: one had received lidocaine and one received 2-chloroprocaine. Three of the eight monkeys had lumbar subpial demyelination with macrophage invasion; two had received bupivacaine, and one received 2-chloroprocaine. No solution produced significant abnormalities in sheep CSF composition. We conclude that no local anesthetic or solution was more neurotoxic than another when injected in large volumes into the subarachnoid space of sheep or monkeys.

Anesthesia, Epidural↗
PubMed1982

Inhibition of epidermal growth factor binding to mouse cultured cells by fibroblast-derived growth factor. Evidence for an indirect mechanism.

Fibroblast-derived growth factor (FDGF), a basic, heat- and acid-stable polypeptide partially purified from the serum-free conditioned medium of BHK cells transformed by simian virus 40, is a potent mitogen for Swiss 3T3 cells and causes a marked reduction in 125I-labeled epidermal growth factor (125I-EGF) binding to these cells. The activity which inhibits EGF binding coelutes with the growth-stimulating activity after gel filtration, ion exchange chromatography, and sodium dodecyl sulfate polyacrylamide gel electrophoresis. Both cellular responses are elicited by the same range of FDGF concentration in several murine cell types. The inhibition of EGF binding is rapid and results from a decrease in the apparent affinity of cellular receptors for 125I-EGF. FDGF does not affect the rate of cell-mediated 125I-EGF degradation. Several lines of evidence suggest that FDGF does not bind directly to EGF receptor. First, the effect of FDGF is dependent on the temperature of the assay; furthermore, treatment of cells with EGF results in loss of EGF receptors while exposure to FDGF for up to 24 h does not induce "down-regulation" of EGF receptors. Further, in A431 cells which display a large number of specific EGF receptors, 125I-EGF binding is not sensitive to FDGF. Finally, the effect of FDGF on 125I-EGF binding is not observed with isolated plasma membranes. Taken together, these findings suggest that FDGF binds to sites which are separate from EGF receptors. The results show a novel mechanism whereby a growth-promoting factor produced by a tumor cell line can rapidly modulate the affinity of the cellular receptors for EGF in an indirect manner.

Animals↗
PubMed1982

Structure of the Drosophila mutable allele, white-crimson, and its white-ivory and wild-type derivatives.

The white locus in Drosophila is required for a normal brick-red eye color; deletions of this locus result in a bleached-white eye color. The white-crimson (wc) allele of white was isolated as a partial revertant of another mutant white allele, white-ivory (wi), a mutation due to duplication of sequences within the white locus. The wc allele reverts at high frequencies to wild-type and wi phenotypes and generates white-eyed derivatives, including deletions with one endpoint at the white locus. We analyzed the structure of the wc allele by molecular cloning and by Southern blot analysis of genomic DNA and found that the wc phenotype results from the insertion of a 10 kilobase DNA sequence into the wi duplication. Five independent phenotypic revertants of wc to wi were examined, and in each case reversion was accompanied by apparently precise excision of the insertion. Reversion of wc to a wild-type phenotype in each of the six cases examined was mediated by excision of both the insertion and one copy of the wi duplication, restoring gene structure to wild-type.

Alleles↗
PubMed1982

FB elements are the common basis for the instability of the wDZL and wC Drosophila mutations.

The DNA insertions that cause the highly unstable mutations wC and wDZL share extensive homology with the FB family of transposable elements. FB elements carry long, internally repetitious, inverted terminal repeats and thus differ in structure from other transposable elements. Our results suggest that FB elements may excise and cause chromosomal rearrangements at unusually high frequencies. The wC insertion is a single FB element. The wDZL insertion differs in that it contains two FB elements, one at each terminus. The wC and wDZL insertions contain 4.0 and 6.5 kilobase nonhomologous segments between their terminal repeats. In contrast to the middle repetitive FB elements, the central segment of the wDZL insertion is single-copy and present at a fixed location in the wild-type genome. It has apparently been transposed by the action of flanking FB elements, causing the wDZL mutation at its new location.

Alleles↗
PubMed1982

Experimental antigen-antibody complex disease in mice. The role of antibody levels, antibody affinity and circulating antigen-antibody complexes.

Chronic antigen-antibody complex disease (A-ACD) was induced in mice by daily injections of HSA. The disease was characterized by death, intense glomerular basement membrane deposition of complexes in the kidneys, proteinuria and an impairment of the glomerular filtration rate. In mice that had been selectively bred to produce antibody of low affinity to protein antigens injected in saline, the incidence of chronic A-ACD was 61% compared to 21% in mice selectively bred to produce antibody of high affinity. Low affinity female mice produced approximately ten times as much free antibody to HSA as did low affinity males and high affinity males and females, but this did not result in an increase incidence of chronic A-ACD in low affinity female mice. Low affinity female mice also had the highest levels of circulating antigen-antibody complexes detected by conglutinin and Clq binding assays, but there was no correlation between the presence of high levels of complexes in serum and tissue damage. In both lines of mice the mean affinity of free antibody to HSA started low and increased with time and the number of injections of antigen. However, development of chronic A-ACD in individual low affinity mice appeared to be associated with a failure to produce this time-associated increase in antibody affinity. These results are discussed with reference to the relevance of the measurement of the amount of affinity of free antibody in serum and the levels of circulating antigen-antibody complexes to the production of tissue damage in this model of chronic A-ACD.

Animals↗
PubMed1982

The psychological significance of somatic complaints.

Patients experiencing psychological distress often come to their physicians with primarily somatic complaints. While patients provide their physicians with multiple clues that there is a functional cause to their complaints, physicians often fail to recognize these. Psychological states, including depression, schizophrenia, hypochondriasis, malingering, conversion reactions, anxiety states, the "identified patient" in a dysfunctional family, and the patient with a "hidden agenda" are examples of this somatization process. Physicians may recognize these problems and avoid needless interventions if they consider these diagnostic possibilities and ask their patients questions that differentiate the various psychological possibilities.

Adult↗
PubMed1982

Vibrotactile stimulation for intersystemic reorganization in the treatment of apraxia of speech.

Intersystemic reorganization in the treatment of apraxia of speech involves pairing fragments of a speech motor program with internal cues generated by some other, more intact system. Gestural reorganization, pairing speech with limb gestures, somehow provides an organizational framework for the proper sequencing of motor speech movements. This paper briefly develops some hypotheses suggesting that afference resulting from limb movements rather than a central movement program is involved in gestural reorganization, and that vibrotactile stimulation may have advantages over visual or auditory modalities. The effectiveness of vibrotactile as compared to auditory stress cues was assessed in a multiple schedule design for 1 patient who had had a cerebrovascular accident. Results indicated that, in an imitative paradigm, vibrotactile plus auditory stress and rhythm cues were more effective than auditory cues alone improving an apraxic patient's imitative production of single words.

Afferent Pathways↗
PubMed1981

The distribution of acetylcholinesterase and choline acetyl transferase in the cerebellum and posterior lateral line lobe of weakly electric fish (Gymnotidae).

Cholinesterase was demonstrated in the caudal lobe of the cerebellum but not the corpus cerebelli of weakly electric gymnotid fish. It had a patchy distribution in the granule cell layer and was very dense in the molecular layer; the cholinesterase staining was also dense in the contiguous molecular layer of the subjacent electrosensory region. Choline acetyltransferase was also found in far greater amounts within the electrosensory region and caudal lobe of the cerebellum than within the corpus cerebelli itself.

Acetylcholinesterase↗