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Biomedical subjects

J Hanson

Publications and source records attributed to J Hanson.

At least 235 records · Page 13Linked to original sources
PubMed1980

Frequency of new mutants among boys with Duchenne muscular dystrophy.

Haldane's rule states that one-third of the cases of an X-linked recessive lethal should represent new mutations. This rule is derived under the assumptions that there is equilibrium between mutation and selection, that mutation rates in ova and sperm are equal, and that heterozygous and homozygous normal women have the same fitness. To test this rule for Duchenne muscular dystrophy (DMD), we have examined the mothers of 55 boys with DMD (16 familial and 39 isolated cases) and classified them as carriers or noncarriers on the basis of measures of ribosomal protein synthesis (RPS). Of the 55 mothers, only nine (16.4%) are classified as noncarriers, a figure significantly different from the expected one-third. When the analysis is limited to the 39 mothers of isolated cases, 23.1% (9/39) are classified as noncarriers, still significantly different than expected under Haldane's rule. Violation of any of the assumptions under which Haldane's rule is derived could lead to deviations from the expected one-third new mutants. We find the most likely explantation to be a higher male than female mutation rate. This is supported also by the finding that maternal grandfathers in whom a mutation occurred had higher mean age at birth of the carrier daughter (33.7 +/- 1.6) than did the general population or intrapedigree controls (29.5 +/- 1.3).

Female↗
PubMed1980

The postnatal development of the inferior oblique muscle of the cat. III. Fiber sizes and histochemical properties.

Transversal sections of the inferior oblique muscle from kittens of various ages and from adult cats were stained for myofibrillar ATP-ase at Ph 9.4 and 4.35, succinic dehydrogenase (SDH) and fat. The same muscles had previously been submitted to studies of contractional and fatigue properties. With ATPase the fibers could be differentiated into types I, II and II C. The percentages of each fiber type remained approximately the same from birth onwards. In the inner, global layer of the muscle, type I fibers showed a linear increase in size, but types II and IIC fibers an accelerated growth after age 20 weeks. In the outer, orbital layer, where no type I fibers were seen, type II and II C fibers showed the same growth pattern as in the global layer. The fiber content of SHD and fat was low at birth but increased after two weeks of age. Type I fibers were poor and type II C fibers rich in SDH and fat. Type II fibers showed varying amounts of these substances. Provided that type I fibers are slow, type II fast and type II C intermediate in speed of contraction, like in other muscles, the findings on fiber growth and SDH content seem to support the idea that slow, fatigue resistant components in eye muscles reach maturity earlier than fast components.

Adenosine Triphosphatases↗
PubMed1980

Heating patterns produced by 434 MHz erbotherm UHF 69.

Thermal distributions of 434 MHz Erbotherm H 69 hyperthermia/diathermy generators in tissue-equivalent medium have been investigated. Thermocouples were used to measure temperatures at a set of grid points. Cylindrical and abdominal phantoms were heated and sectioned after heating to measure the temperatures at depth. Results indicate that there is potential for heating deep-seated tumors. The distributions were influenced by the number, shape and geometry of the applicators employed.

Diathermy↗
PubMed1980

Accuracy of echoventriculography as compared with computer tomography in children.

The accuracy of echoventriculography (echo-VG) using CT findings as a reference has been examined in 144 children. Lateral ventricular index on echo-VG was compared with anterior horn and body indices on CT. The correlation coefficient was 0.617 and 0.725, respectively. Twelve cases with a deviation exceeding 2 SD in the regression between the indices were analysed. The conclusion is that echo-VG is fairly accurate and useful as a screening method and for follow-up examinations in children.

Adolescent↗
PubMed1980

The effects of extremes of age on drug action.

Many examples of age-related differences in the response of individuals to a particular drug have been documented. In many cases these differences can be related to modified distribution, metabolism or excretion of the drug. There is evidence that in neonates and the elderly, the extent and rate of these processes are less than those in older children and young adults. However, in a given age group there is no consistent trend for all drugs. In some cases the increased plasma concentration of the drug would be regarded as an advantage as it prolongs the response, but it is certainly not true for drugs such as streptomycin, warfarin and the hypoglycemic agents. Two points which emerge from the results of many studies with neonates and the elderly are that interindividual variations in plasma half-lives, metabolite and drug excretion and protein binding are significantly larger than those in young adults and that in the case of the elderly, chronological age does not necessarily reflect biological age. In combination these factors emphasise the importance of individual drug monitoring of plasma levels and hence of knowing the pharmacokinetic constants of the drug in the individual patient. In clinical practice, the dose of a drug is most commonly calculated on the basis of body weight or surface area. This is generally perfectly acceptable for older children and adults, but is not always a reliable formula for neonates and the very old. Simple changes in such parameters as urine pH can override calculations based upon body size.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1979

Cancer of the bladder in Alberta: a urologic audit review.

A review was conducted of 660 cases of cancer of the bladder diagnosed in two periods, 1960--62 and 1968--70. A significant increase in the incidence of bladder cancer in both sexes, paralleling the trends in other parts of North America, was found. During the second period the disease was diagnosed earlier and, once diagnosed, was apparently treated more successfully. Overall 5-year survival rates increased from 57% to 70% for patients with stage O or A disease, but were relatively constant, at about 36%, for patients with stage B1 or B2 disease. The survival rate for patients with stage O or A disease appeared to improve without clearly defined changes in treatment. Prospective randomized treatment trials are needed to properly assess the value of definitive and adjunctive methods of treatment.

Adenocarcinoma↗
PubMed1979

Rieger's syndrome. A case report with a 15-year follow-up.

A 15-year follow-up examination of a boy with Rieger's syndrome showed that the anterior segment changes in this disease may be slowly progressive in the absence of glaucoma or miotic treatment. The patient also had two recently recognized systemic features of the syndrome, umbilicus cutis and hypospadias.

Adolescent↗
PubMed1979

Contractile properties of extraocular muscle in cats reared with monocular lid closure and artificial squint.

Kittens were raised with amblyopia by monocular lid suture or esotropia by transection of extraocular muscles in one eye at the age of 2--3 weeks. Isometric contractions in the inferior oblique muscle were recorded at 20 weeks or at adult age, and the results were compared with those of similarly aged cats with normal visual development. The speed of contraction and the fatigue resistance was reduced in the lid sutured animals. In the esotropic cats studied, fatigue resistance was also reduced but the speed of contraction did not change much. It is suggested that the postnatal eye muscle development can be modified by manipulation of the visual input at an early age. Presumably the impaired binocular vision in the lid sutured and esotropic cats reduced the demand for fusion vergences, and this might be reflected in the changes of eye muscle properties. In monocularly lid sutured cats, eye muscle changes were the same on both sides, suggesting that amblyopia per se did not affect eye muscle development.

Age Factors↗
PubMed1979

Suspected reticuloendotheliosis in turkeys with cutaneous lesions reminiscent of fowl pox.

Twelve turkeys from a flock of 2,500 had cutaneous lesions somewhat resembling fowl pox. Lymphoid-like tumors were evident in livers and spleens. Closer examination of cutaneous lesions, and histopathological examinations indicated skin lesions were also infiltrative and not unlike reticuloendotheliosis. Electron micrographs revealed the presence of C-type virus particles.

Animals↗
PubMed1979

Successful management of popliteal arterial disruption in Ehlers-Danlos syndrome.

A review of the literature on Ehlers-Danlos syndrome with particular attention to vascular complications enabled us to outline an orderly diagnostic and therapeutic plan which has allowed salvage of an individual with a popliteal false aneurysm. In patients with Ehlers-Danlos syndrome and brachial, superficial femoral, or popliteal arterial disruption, the use of proximal tourniquet control to allow ligation of the disrupted artery under a no-flow, no-pressure situation is recommended. The ligations should be carried out with a large ligature or possibly with large hemoclips and/or reinforced with multiple fine atraumatic vascular sutures distally. These patients may be treated successfully for flexion contractures because of the laxness of their tissues.

Adolescent↗
PubMed1978

The postnatal development of the inferior oblique muscle of the cat. I. Isometric twitch and tetanic properties.

The postnatal development of the inferior oblique muscle in the cat has been studied with physiological and histochemical techniques. This paper describes the changes with age in isometric twitch and tetanic response characteristics. The twitch amplitude increased and the twitch contraction time (ct) and half-relaxation time (hrt) decreased almost linearly from birth to adulthood. The relation between the strength of nerve stimulation and twitch ct and hrt changed during development with a threshold slow response appearing at 10 weeks. Twitch responses in cats 6 weeks of age or older were of longer duration than in younger cats, in spite of the longer ct and hrt in young cats. Fusion frequency of the tetanic response reached a constant level in muscles 6 weeks or older. The maximum rate of tension rise remained the same from birth to 6 weeks of age and later increased markedly up to 20 weeks of age. The contracture induced by succinylcholine was the same in muscles of all ages. These data were related to previous findings on the postnatal development of fast and slow muscles and motor units in the hindlimb of the cat. A differentiation of the development of fast and slow eye muscle fibers is suggested. Slow fibres seemed to have completed their maturation at about ten weeks of age, while the development of fast fibre properties continued, probably up to the adult stage.

Age Factors↗
PubMed1978

The postnatal development of the inferior oblique muscle of the cat. II. Effects of repetitive stimulation on isometric tension responses.

The changes with postnatal age in post-tetanic potentiation (PTP) and fatigue of the inferior oblique muscle have been studied in the cat. PTP of the twitch amplitude increased steadily with age up to 20 weeks after birth. Twitch contraction time (ct) and half relaxation time (hrt) was not significantly changed. The potentiation of the tetanic response also became more prominent with age. The young muscles (10 weeks and below) were slightly more susceptible to fatigue than older muscles, but recovery was rapid in muscles of all ages. Intensive stimulation induced post-tetanic depression of twitch responses in muscles older than 1 week, but none in the muscles of new-born cats. Ct and hrt were greatly prolonged in muscles above six weeks of age. In these muscles, but never in the very youngest, repetitive firing could be observed in response to post-tetanic single nerve stimulation. The results are compared with those obtained in similar experiments on hind-limb muscles by other workers. They further support the idea, raised in a previous paper, that slow eye muscle fibres develop quicker and reach maturity earlier than fast fibres.

Age Factors↗
PubMed1977

Breast cancer in northern Alberta: pilot study in computerized registration.

Analysis of data from 643 breast cancer patients seen between 1971 and 1973 in northern Alberta was undertaken as a preliminary study leading towards a comprehensive breast registry. Age at first treatment and menopausal status were found to be related significantly to the clinical stage of the disease. Other data reported included age at menarche, lymph node involvement and methods of primary treatment. A decline in use of the radical mastectomy was noted. The comprehensive breast registry, which will be used to identify high-risk groups, assess treatment modalities, test hypotheses and generate ideas, has a high probability of success because of compulsory registration of new cases of breast cancer in Alberta and collection of data by the same four individuals.

Adolescent↗