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Biomedical subjects

M Hanson

Publications and source records attributed to M Hanson.

At least 145 records · Page 8Linked to original sources
PubMed1981

Inhibition of rapid axonal transport in vitro by the ionophores X-537 A and A 23187.

The effects of the ionophores X-537 A and A 23187 on axonal transport (AXT)' high energy phosphates, levels of Ca2+ and ultrastructure were investigated in frog sciatic nerves in vitro. X-537 A at 0.09 muM blocked AXT of [3H]labelled proteins by 50% as judged by ligature experiments while the levels of ATP and CrP remained unchanged. Pulse-label experiments showed that the amount of transported material decreased whereas the rate of AXT was only slightly retarded. Elevated extracellular levels of Ca2+ (5mM) potentiated the inhibitory effect of the ionophore. In contrast, ruthenium red counteracted the ionophore induced inhibition of AXT. A 23187 at 10 muM but not at 2 muM inhibition AXT but also reduced the ATP and CrP levels. In pulse-label experiments A 23187 displayed similar but less pronounced effects than X-537 A. Both ionophores increased the total calcium content of the nerve and appeared to decrease the amount of axonal mictotubles (MT). As X-537 is a very potent inhibitor of AXT it may prove a valuable tool in exploring the relations between AXT, Ca2+ and MT.

Adenosine Triphosphate↗
PubMed1981

An investigation of the efficacy of oral myofunctional therapy as a precursor to articulation therapy for pre-first grade children.

This study investigated the assumption that oral myofunctional services might facilitate remediation of articulation disorders. Subjects were ten 6-year-old elementary school children who exhibited both tongue-thrust behaviors and articulation errors. All subjects had equal service time for a 14-week period, half receiving articulation services only and the other half receiving oral myofunctional services prior to and in conjunction with articulation services. Results showed that children in both programs made essentially equal progress in correcting placement of tongue-tip sounds, remediating /s/ and /z/ misarticulation, and remediating general articulation errors. Only children who received oral myofunctional services remediated tongue-thrust behaviors.

Articulation Disorders↗
PubMed1981

Axonal transport in transplanted frog sciatic nerve.

Axonal transport was studied in transplanted frog sciatic nerves-dorsal ganglia for periods up to three months. The ganglia were either labeled prior to, or after varying periods of transplantation and the distribution of labeled proteins compared. The survival of the preparations was assessed by studying their ability to transmit compound action potentials, to maintain axonal transport and by their ultrastructural appearance. The sensory neurons retained their fast axonal transport and excitability during the transplantation periods. Morphologically about 30% of the axons appeared normal after one month of transplantation. The amount and distribution of protein incorporated radioactivity in the ganglia and the nerve changed with time but the decrease in the ganglia was not accompanied by a corresponding increase in the nerve. There was no evidence for a distinct slow phase of transport in spite of a functional fast transport system. The results indicate that either slow transport stops when the normal balance between release, degradation and recirculation is distributed by the presence of a ligature or that there is a continuous change in the composition of transported material with the time after labeling which is not reflected in altered transport characteristics.

Animals↗
PubMed1980

Ca2+- or Mg2+-dependent enzymatic ATP hydrolysis associated with the microsomal fraction of frog sciatic nerves.

The microsomal fraction of frog sciatic nerves was found to contain Ca2+- or Mg2+-dependent hydrolytic activity toward different nucleoside di- and triphosphates. In the presence of Ca2+ substrate specificity was in the order CTP > UTP > GTP > ATP. When Mg2+ was used, the triphosphates were approximately equally good substrates. ATP hydrolytic activity was very similar with Ca2+ or Mg2+ as the cofactor, whereas Ca2+ was the more potent activator of hydrolysis of the other triphosphates tested. The preparation showed some activity toward the nucleoside diphosphates but none toward the monophosphates or p-nitrophenylphosphate. The enzymic properties of ATP hydrolysis were more closely studied. The hydrolysis was optimal at 18--24 degrees C in the presence of 1 mM-Ca2+ or 1 mM-Mg2+. Ca2+- and Mg2+-ATP hydrolysis displayed pH maxima around 8.0--8.5 and 7.4--8.0, respectively. Vmax values for Ca2+- and Mg2+-ATP hydrolysis similar: approx. 12 mumol Pi per h per mg protein with a Km value of approx. 0.05 mM. The ATP hydrolysis activity was inhibited by NaF but unaffected by ouabain, vanadate, cytochalasin B, and various drugs known to influence ATPase activity of mitochondria. Zn2+ stimulated the ATP hydrolysis activity at low concentrations (10(-6)-10(-5) M) and inhibited it at higher concentrations. The possibility that these observations account for stimulation and inhibition of axonal transport in frog sciatic nerves exposed to similar concentrations of Zn2+ is discussed.

Adenosine Triphosphate↗
PubMed1980

Surgical treatment of compressive cervical band.

Compression of the lower portion of the brachial plexus by a cervical band continuous with the scalenus medius is a rare but well-defined cause of arm pain. The syndrome should be suspected in a patient who presents with chronic arm pain and thenar atrophy. Cervical ribs or prominent C-7 transverse processes will be present on an anteroposterior roentgenogram of the cervical spine, and the diagnosis is confirmed by characteristic electromyographic findings. The syndrome should be differentiated from other causes of chronic arm pain, such as herniated cervical disc, syringomyelia, spinal cord tumor, or carpal tunnel syndrome. The condition is readily treated by surgical division of the compressive band, approached through a supraclavicular incision.

Adult↗
PubMed1980

AABB-CAP survey data on hepatitis--incidence, surveillance, and prevention.

The number of HBsAg-positive blood donors detected by routine hepatitis screening and the incidence of transfusion-associated hepatitis reported by participants in the AABB-CAP Viral Hepatitis Proficiency Survey are comparable to data reported from similar sources. Reports on hepatitis surveillance in health care personnnel suggest a higher risk of hepatitis associated with increased handling of tissue and body fluids.

Blood Donors↗
PubMed1979

Therapy of endodermal sinus tumor of the ovary.

Endodermal sinus tumor of the ovary can be differentiated histologically and immunohistochemically from ovarian embryonal cell carcinoma. A case report of a patient with endodermal sinus tumor is presented in which a long-term remission was achieved by unilateral adnexectomy and combination chemotherapy. Review of the current literature indicates that tumor removal followed by combination chemotherapy with vincristine, actinomycin D, and cyclophosphamide is the most effective method of therapy for this highly malignant ovarian neoplasm. The addition of hysterectomy with contralateral ovariectomy or radiation therapy does not appear to significantly improve the survival of patients with this tumor. Serial plasma determinations of alpha fetoprotein provide biochemical monitoring of response to therapy and may be useful in predicting occult tumor recurrence.

Adolescent↗
PubMed1979

Therapeutic implications of patterns of recurrence in cancer of the uterine cervix.

Five hundred twenty-six patients with invasive cervical cancer, treated at the University of Kentucky from 1964 to 1976, were followed 2--12 years after therapy. One hundred and sixty patients (31%) developed tumor recurrence. Recurrent cancer was noted with 1 year after therapy in 58% of patients and within 2 years of treatment in 76% of patients. Only 6% of patients with recurrent cervical cancer survived 3 or more years. Stage of disease, cell type, lesion size, and the presence of lymph vascular space invasion by tumor cells were all shown to be prognostically significant. The addition of extrafascial hysterectomy to radiation therapy significantly decreased the incidence of recurrence in stage IB cervical tumors 5 cm or more in diameter. Analysis of this data suggests that radical hysterectomy and pelvic lymphadenectomy is as effective as irradiation only in the treatment of large cell squamous carcinomas 2 cm or less in diameter.

Adenocarcinoma↗
PubMed1979

Potential risk of salivary-mediated viral hepatitis type B transmission from oral exposure to fomites.

Twelve grade school and junior high school students had oral exposures to hepatitis B surface antigen (HBsAg) positive saliva via contact with contaminated musical instruments. The 12 exposed students and 18 students who served as age and sex matched controls were tested for the presence of HBsAg and antibody to the hepatitis surface antigen (anti-HBs) at 2 weeks, 8 weeks and 6 months after exposure. All students were negative for HBsAg and anti-HBs on all dates tested and reported no illness during that time suggestive of viral hepatitis. There was no evidence of viral hepatitis, type B transmission from the exposure. The students probably experienced the maximum possible oral exposure from direct or fomites contact, since there was no cleaning of the musical instruments between use by the students and teacher. Based on these results, the risk of transmission of viral hepatitis, type B from oral contact with fomites is unlikely.

Adolescent↗
PubMed1979

Inhibition of fast axonal transport and microtubule polymerization in vitro by colchicine and colchiceine.

The effects of colchicine and colchiceine on fast axonal transport in frog sciatic nerves were studied in vitro. Colchiceine inhibited the transport to about the same extent as colchicine. Preincubation at low temperature potentiated the inhibitory effect of either drug. The polymerization of purified brain tubulin was inhibited by colchiceine at 5-10 times higher concentrations than colchicine. The similarity of the effects obtained with colchicine and colchiceine indicates that both drugs arrest axonal transport by interfering with microtubule function. Colchicine and colchiceine did not affect the levels of high energy phosphates (ATP and CrP) in frog nerves indicating that a reduced energy supply was not responsible for the arrested transport.

Adenosine Triphosphate↗