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Biomedical subjects

M R Hanson

Publications and source records attributed to M R Hanson.

At least 73 records · Page 4Linked to original sources
PubMed1989

High-signal periventricular lesions in patients with sarcoidosis: neurosarcoidosis or multiple sclerosis?

The vast majority of periventricular abnormalities visualized with MR imaging in patients less than 50 years old represents multiple sclerosis (MS) lesions. There are many other causes of periventricular lesions, most of which can be differentiated from MS on the basis of history and physical or MR findings. Five cases of biopsy- or Kveim test-proved sarcoidosis with MR findings consistent with MS are reported. Each of these patients, diagnosed as having sarcoidosis, had symptoms identical to those seen in MS. Although these patients have not had histologic characterization of the intraparenchymal lesions seen on MR, they illustrate the difficulty of differentiating sarcoidosis with CNS involvement from MS in some patients on the basis of clinical, radiographic, electrodiagnostic, or CSF testing. This series contributes to a growing body of evidence that neurosarcoidosis probably should be included in the differential diagnosis of isolated periventricular lesions in patients less than 50 years old.

Adult↗
PubMed1989

Transfusion-associated hepatitis C virus (non-A, non-B) infection.

Non-A, non-B (NANB) is a term used to describe viral hepatitis not due to hepatitis B virus or hepatitis A virus. Two forms of NANB hepatitis have been identified: (1) an epidemic type usually transmitted enterically and (2) a parenterally transmitted form caused by hepatitis C virus. While the latter often is assumed to be transfusion transmitted, data from surveillance programs suggest that the incidence of NANB transfusion-associated hepatitis (TAH) is decreasing. Strategies for preventing TAH include viral inactivation, testing for surrogate markers of NANB, and the appropriate use of blood components. Whether alanine aminotransferase and antibody to hepatitis B core antigen screening of donated blood will be effective in reducing the incidence of TAH is yet to be established. Specific tests for anti-hepatitis C virus may resolve problems associated with surrogate testing.

Alanine Transaminase↗
PubMed1988

Amyotrophic lateral sclerosis. Recent advances in pathogenesis and therapeutic trials.

We reviewed the current status of pathogenesis and therapeutic trials in amyotrophic lateral sclerosis (ALS). Clinical studies have identified several rare but definable causes for apparent ALS. Certain clinical features previously considered unlikely to occur in ALS are found on careful examination. Epidemiologic surveillance and recent studies of neurotoxic plant seeds used in Guam have shed light on the pathogenesis of endemic ALS. Extensive analyses of biochemical, metabolic, immunologic, viral, and toxic factors have provided provocative results requiring further studies. Reflecting on some of these hypotheses, therapeutic trials have been performed more vigorously than ever. Amyotrophic lateral sclerosis is now investigated at the molecular genetic level. Human autopsy and experimental animal studies have expanded our understanding of basic mechanisms involving motoneuronal degeneration. In the future, we must continue a relentless search for the pathogenesis of ALS, prospective clinical studies to define the limits of ALS, and well-designed, controlled therapeutic trials.

Amyotrophic Lateral Sclerosis↗
PubMed1988

A functional mitochondrial ATP synthase proteolipid gene produced by recombination of parental genes in a petunia somatic hybrid.

A novel ATP synthase subunit 9 gene (atp9) was identified in the mitochondrial genome of a Petunia somatic hybrid line (13-133) which was produced from a fusion between Petunia lines 3688 and 3704. The novel gene was generated by intergenomic recombination between atp9 genes from the two parental plant lines. The entire atp9 coding region is represented on the recombinant gene. Comparison of gene sequences indicate that the 5' transcribed region is contributed by an atp9 gene from 3704 and the 3' transcribed region is contributed by an atp9 gene from 3688. The recombinant atp9 gene is transcriptionally active. The location of the 5' and 3' transcript termini are conserved with respect to the parental genes, resulting in the production of hybrid transcripts.

Amino Acid Sequence↗
PubMed1988

ENG-MRI correlates in cerebellar oculomotor dysfunction.

This study correlates ENG and MRI findings in six patients with cerebellar eye movements. For each subject, both tests independently support the presence of a cerebellar tract abnormality. In two patients, MRI studies confirmed the site of cerebellar dysfunction previously demonstrated by ENG. Although the number of patients is small, the strong correlation (100%) indicates that ENG remains a sensitive method for detection and localization of the origin of cerebellar eye movements. The physiologic information provided by ENG is supported anatomically by MRI. The cerebellar eye movement abnormalities are briefly reviewed.

Adolescent↗
PubMed1988

Neuro-ophthalmologic complications of cardiac catheterization.

We examined ten patients who, from 1981 to 1986, sustained neuro-ophthalmologic events during cardiac catheterization. Eight patients, most of whom recovered, were believed to have sustained embolic phenomena. Two patients experienced a typical migraine during the catheterization and likewise did well. We conclude that the likelihood of sustaining a neuro-ophthalmic complication during cardiac catheterization is low and that the prognosis after having sustained such a complication is generally favorable. Evidence suggests that artery-to-artery emboli is the dominant pathogenic factor.

Aged↗
PubMed1987

A fused mitochondrial gene associated with cytoplasmic male sterility is developmentally regulated.

Sequencing of an open reading frame associated with cytoplasmic male sterility (CMS) in Petunia has revealed a gene fusion (the Pcf gene) containing the 5'-flanking and amino-terminal transmembrane segment of the ATP synthase proteolipid gene (atp9), parts of the cytochrome oxidase subunit II (coxII) coding region, and the carboxyl terminus and 3'-flanking region of an unidentified reading frame (urfS). The coxII region has several small deletions and tandem repeats that remove all of the segments coding for the residues involved in copper binding, but may possibly maintain the cytochrome c binding site. Normal atp9 and coxII genes and their transcripts are also present in the sterile cytoplasm. S1 nuclease protection studies identify fused gene transcripts only in CMS lines, with an increase in transcript amount in anthers relative to leaves.

DNA, Mitochondrial↗
PubMed1987

Different transcript abundance of two divergent ATP synthase subunit 9 genes in the mitochondrial genome of Petunia hybrida.

The mitochondrial genome of Petunia hybrida line 3704 has been found to contain two transcribed genes for the proteolipid subunit of the ATP synthase complex (atp 9). The 5' and 3' flanking sequences of the second atp 9 gene differ from those of another atp 9 gene previously sequenced by Young et al. (1986), while the coding region exhibits only one silent base change. The transcript termini of the two divergent atp 9 genes map to different locations, most of which are surrounded by sequences homologous to putative mitochondrial transcription signals (Hiesel and Brennicke 1985; Schuster et al. 1986; Young et al. (1986). Because transcripts from the atp 9 genes differ in abundance, divergence in the flanking regions of these two genes must affect regulatory elements which control either transcription rate or transcript stability.

Amino Acid Sequence↗
PubMed1987

Respiratory insufficiency in adult-onset acid maltase deficiency.

Although the adult form of acid maltase deficiency is characterized by weakness of the limb girdle muscles, weakness of the respiratory muscles out of proportion to that of the limb muscles may make the diagnosis less obvious. We present four patients aged 35 to 57 with respiratory muscle weakness associated with signs of cor pulmonale and symptoms of alveolar hypoventilation. Each had symptoms of fatigue, hypersomnolence, morning headache, and orthopnea, the cause of which was misdiagnosed. The key to diagnosis was paradoxic abdominal motion on inspiration. This finding, consistent with diaphragmatic paralysis, led to neurologic evaluation, electromyographic examination, and muscle biopsy to confirm the diagnosis. The symptoms of alveolar hypoventilation were reversed with chronic nocturnal ventilation, which assisted in rehabilitating some patients.

Adult↗
PubMed1986

Sequence and transcription analysis of the Petunia mitochondrial gene for the ATP synthase proteolipid subunit.

We have sequenced the Petunia hybrida gene that specifies the proteolipid subunit of the mitochondrial Fo ATP synthase and have used this gene to investigate plant mitochondrial gene transcription. The Petunia atp 9 gene contains a single open-reading frame capable of specifying a 77 amino acid-polypeptide that is homologous to bovine, fungal and maize proteolipid subunits. S1 protection identified 3 transcripts in a ratio of 1:5:100 in the Petunia tissues tested. The transcripts share a common 3' terminus but have 5' termini that map 528, 266, and 121 nucleotides upstream of the translation start site. The 5' terminus of the longest transcript maps to the sequence ATATAGTA, which is nearly identical to the yeast mitochondrial transcription initiation site ATATAAGTA. Primer extension analysis indicates that these two shorter transcripts are not due to splicing. The two shorter transcripts originate at sequences homologous to sites at 5' termini of two pea and maize genes. These consensus sequences may signal processing events other than splicing.

Amino Acid Sequence↗
PubMed1986

Selective saccadic palsy caused by pontine lesions: clinical, physiological, and pathological correlations.

Two patients suffered a selective deficit of voluntary saccades and quick phases of nystagmus after hypoxic-ischemic insults during open-heart surgery. All voluntary saccades, in both horizontal and vertical planes, were slow, and quick phases of vestibular and optokinetic nystagmus were absent. Smooth pursuit, the vestibuloocular reflex, the ability to hold steady eccentric gaze, and vergence eye movements were all preserved. Pathological studies in 1 patient confirmed neuronal necrosis and gliosis, consistent with ischemic lesions involving the median and paramedian pontine reticular formation and median basis pontis but sparing the rostral mesencephalon and rostral interstitial nucleus of the medial longitudinal fasciculus. These findings, taken with data from experimental studies, support the hypothesis that each functionally defined class of horizontal eye movements is controlled by a separate neural substrate that projects independently to the abducens nuclei. In addition, these data suggest that the rostral interstitial nucleus of the medial longitudinal fasciculus is dependent on inputs from the paramedian pontine reticular formation for the programming of normal vertical saccades.

Adult↗
PubMed1986

Results of sinusoidal harmonic acceleration test in one thousand patients: preliminary report.

One thousand patients with dizziness were tested by sinusoidal harmonic acceleration with frequencies of .01, .02, .04, .08, and .16 Hz. Two hundred fifty (25% of data base) were randomly selected for this study. One hundred forty-eight diagnoses were confirmed: 66 (45%) patients had a clinical diagnosis of peripheral vestibular dysfunction, 28 (19%) had central vestibular dysfunction, and 53 (36%) had dizziness of undetermined cause. This preliminary study investigated the response patterns of phase (latency), asymmetry (slow phase preponderance), and gain (output/input) as they correlated with each of the above patient groups. The main response pattern was a varying degree of asymmetry with normal or abnormal latency. Persistent abnormal phase pattern indicated permanent vestibular damage and could not be used reliably to differentiate peripheral from central vestibular dysfunction. Asymmetry changed with time and correlated with patients' symptoms. The dynamic pattern of asymmetry could be used to differentiate peripheral from central vestibular dysfunction. Gain was a reliable and essential measure of the sensitivity of the vestibular system and the validity of the rotational response.

Dizziness↗
PubMed1986

Amyotrophic lateral sclerosis: effects of acute intravenous and chronic subcutaneous administration of thyrotropin-releasing hormone in controlled trials.

We performed double-blind crossover trials to assess the effects of thyrotropin-releasing hormone (TRH) on amyotrophic lateral sclerosis patients. For acute intravenous trials, 500 mg TRH or placebo with norepinephrine was given at 1-week intervals (16 patients). CSF TRH concentration increased, and clinical side effects appeared with TRH. For chronic studies, 25 mg TRH and a saline placebo were given subcutaneously every day for 3 months (25 patients). CSF TRH level increased 29-fold after a single TRH injection, and mild transient side effects occurred. Vital signs, respiratory function, semiquantitative and quantitative neurologic function, muscle strength by manual and dynamometer testing, and EMG were studied. With daily TRH, 10 patients noted subjective improvement without objective evidence, and 10 patients complained of worsening of the disease with objective decline after TRH was stopped. Statistical analysis, however, showed no beneficial effects from either acute or chronic TRH trials.

Adult↗
PubMed1985

Developmental anomalies of the optic disc and carotid circulation. A new association.

Three patients with developmental abnormalities of the optic disc (two morning glory anomalies and one retinochoroidal-optic disc coloboma) had angiographically documented aberrancies of the carotid circulation including large trunk occlusions, moya-moya-like collaterals, dolichoectasia, and absent ophthalmic artery. Although developmental optic disc abnormalities have been linked with other problems such as basal encephalocele, congenital heart defects, and eyelid hemangiomas, these three patients are the first to our knowledge to have related malformations of the intracranial circulation. We suggest, therefore, that the presence of a congenital optic disc anomaly may herald a similar defect in the cerebral circulation.

Abnormalities, Multiple↗
PubMed1984

Focal inflammatory myopathy.

We report three patients with inflammatory myopathy who presented clinically with weakness and wasting of only one limb. The myopathy progressed over 6 months and 5 years, respectively, in two patients and was stable after 8 years in the third patient. One patient had a skin rash. Serum CK was elevated in the two patients with progressive disease. Electromyography showed brief duration, small amplitude motor unit potentials and fibrillations in the affected limbs. Muscle biopsy revealed variable fiber size, degenerating and regenerating fibers, and inflammatory foci. Vasculitis was seen in the patient with skin lesions and marked fibroblastic proliferation in the patient with the most chronic course. Immunosuppressive therapy has arrested the progression in the two patients treated; both have regained strength.

Adult↗
PubMed1983

Mechanism and frequency of brachial plexus injury in open-heart surgery: a prospective analysis.

A computer-assisted prospective analysis of 531 patients undergoing open-heart operations revealed that 26 patients (5%) sustained brachial plexus injury. In 22 of the 26 patients (85%), the lesion involved the lower trunk or C8-T1 nerve roots. Electromyograms confirmed the clinical impression in 13 patients. In 19 of the 26 patients (73%), the side on which the plexus lesion was found correlated with the side of internal jugular vein cannulation. Because of the anatomical proximity of the lower trunk to the internal jugular vein and the preponderance of lower trunk lesions, we postulate that traumatic cannulation may be a major mechanism of plexus injury. Thus, the resulting syndrome of pain, dysesthesias, and hand weakness may sometimes be preventable.

Adult↗
PubMed1983

Radioimmunoassay and enzyme immunoassay methods for detecting viral hepatitis markers.

Enzyme immunoassay (EIA) and radioimmunoassay (RIA) methods for HBsAg were compared on the basis of responses to the AABB-CAP Viral Hepatitis Marker proficiency survey. Conversion of laboratories to the EIA method was documented for the period studied. Using standard incubation procedures, participants using the EIA method reported results comparable to those reported by laboratories using RIA methods. The short incubation procedures for RIA and EIA were both less sensitive and less specific than standard incubation procedures.

Hepatitis B↗