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Biomedical subjects

S J Hall

Publications and source records attributed to S J Hall.

At least 73 records · Page 4Linked to original sources
PubMed1991

Red blood cell deformability in sudden sensorineural deafness: another aetiology?

Red blood cell deformability (RCD) was measured by a filtration technique in 12 patients with sudden sensorineural deafness. Five patients had reduced deformability, including 3 out of 4 patients with a recent upper respiratory tract infection. This may be an important factor in sudden deafness, more likely as a complicating factor of other disorders rather than as a truly primary aetiology. Factors and diseases which alter RCD are discussed and a possible link between the viral and vascular causes of idiopathic sudden deafness is suggested. While several lines of therapy seem promising there is still no clinically proved method for improving RCD. With the development of an acceptable therapeutic regimen, we feel that the possibility of reduced RCD should be considered and that a deformability test be included in the work-up of patients with a sudden sensorineural hearing loss.

Adult↗
PubMed1989

Effect of betahistine dihydrochloride compared with cinnarizine on induced vestibular nystagmus.

The effect of betahistine compared with cinnarizine on induced vestibular nystagmus was evaluated using a rotating chair, in 6 healthy volunteers. The subjects underwent a slow acceleration followed by a sudden stop. Electronystagmograph tracings were taken initially as pretreatment control values, and after betahistine 8 mg t.i.d. and cinnarizine 15 mg t.i.d. had been taken. The duration of nystagmus and average eye speed were measured. No difference was recorded in either parameter between the pretreatment rotation and that following betahistine (P greater than 0.05). A significant difference (P less than 0.05) was seen in the duration of nystagmus during initial acceleration, and in average eye speed following the sudden stop after treatment with cinnarizine.

Adult↗
PubMed1988

Effects of extremity loading upon energy expenditure and running mechanics.

Physiological and mechanical consequences of running with commercially available hand and/or ankle weights were examined. Five males and three females (age 30 to 56 yr) ran for 30 min on a treadmill (0% grade) at a self-selected pace (8.9 to 13.7 km.h-1), under randomized conditions of: (i) unloaded weights; (ii) hand weights; (iii) ankle weights; and (iv) hand + ankle weights. Respiratory gas exchange determinations, heart rates, and sagittal view film clips were obtained at selected time intervals. Highest energy expenditures and heart values were obtained for the fully loaded condition, with intermediate values measured for independent hand- and ankle-weighted trials. Increased energy expenditure due to loading ranged from 5 to 8%. Lower extremity kinematics were unaffected by loading. Angular velocity and excursion of the arm segments was significantly (P less than 0.05) reduced when hand weights alone were carried. The results indicate that commercial claims of marked increases in energy expenditure during running with hand/ankle weights are exaggerated. It appears that the small actual increases in energy expenditure, the potential for increased impact forces, and the relative discomfort of carrying weights discredit running with hand and/or ankle weights as a desirable exercise alternative.

Adult↗
PubMed1988

Distribution of ferric iron in larval lampreys, Petromyzon marinus L.

The distribution and abundance of ferric iron in larval lampreys (Petromyzon marinus L.) were investigated using light microscopy and the Prussian blue stain. Animals from various watersheds contained different concentrations of iron, although the sites of deposition were the same for all animals. A major portion of iron is within adipose tissue, while the liver, and cartilage contain predominantly low to trace amounts of iron, respectively. Iron is associated with fibrous connective tissue in several places in the body, and this association may have particular significance in the inner ear. Iron is also located in cells of the meninges. The presence of iron in the epithelial cells of the posterior intestine may reflect elimination of the metal through the extrusion of iron-loaded cells into the intestinal lumen. Iron within mucous cells of the epidermis, suggest elimination of iron during mucous secretion. Iron-loaded cells of bipolar shape are also present in the epidermis, but are particularly prominent around the branchiopore. Low concentrations of iron are observed within in melanin-containing macrophages (melano-macrophages) in regions of iron absorption, erythrophagocytosis, and haemopoiesis. High levels of iron in the epithelia and lumina of pronephric tubules are concomitant with degeneration of this organ. These data are evidence of the wide spread distribution of iron in lamprey tissues and additional evidence for the potential value of lampreys for the study of iron metabolism in vertebrates.

Animals↗
PubMed1986

Multiple mating and siring success during natural oestrus in the ewe.

Ewes were each mated on four separate occasions, at 3, 9, 15 and 21 h after the start of oestrus and at each time by a different ram. The progeny were assigned to sires by blood typing, supplemented by resemblance between lambs and rams. The paternity of 64 lambs, born to 41 ewes, was established: 2 were conceived at a 3-h mating, 27 at 9h, 23 at 15 h and 12 at 21 h. The optimum time for a ram to inseminate, when in competition with others, is therefore 9-15 h after onset of oestrus, and this finding accords with behavioural observations. Ewes tended to lamb during the same half of the day as that when they had come into oestrus.

Animals↗
PubMed1986

Mechanical contribution to lumbar stress injuries in female gymnasts.

Because female gymnasts as a group display higher than average incidences of stress-related pathologies of the lumbar spine, it was of interest to evaluate mechanical factors which are potential contributors. Lumbar hyperextension and impact forces were quantified for performances of five commonly executed gymnastics skills by four competitive collegiate women gymnasts. The skills performed were the front walkover, the back walkover, and the front handspring, the back handspring, and the handspring vault. Wielke's (1983) radius method was used to quantify lumbar curvatures from film data during normal relaxed standing postures and during subject performances of the five selected skills. A force platform was used to monitor vertical and lateral ground reaction forces at the terminations of the respective skill performances. Of the skills examined, the handspring vault produced the highest vertical and lateral impact forces, and the back handspring and back walkover required the greatest amounts of lumbar hyperextension. During the front and back walkovers and during the back handspring, maximum lumbar hyperextension occurred very close to the time that impact force was sustained by either the hands or the feet.

Athletic Injuries↗
PubMed1985

Posterior capsule opacification: experimental analyses.

The lenses of New Zealand White and Flemish Giant rabbits were removed using five techniques representative of the different clinical approaches to extracapsular cataract extraction currently employed. Posterior capsule opacification developed in all experimental animals within 6 weeks of the operation. None of the techniques reduced the incidence of the capsular opacification. Histological analyses including immunofluorescent and tritiated thymidine labelling were used to determine the nature of the cellular constitutents of the secondary membrane. The evidence indicates that the opacity is due not only to lens cells remaining after the operation but also consists of cells of nonlenticular origin. The data strongly implicate the anterior uvea as the source of those cells. Furthermore, the findings suggest that posterior capsule opacification is the product of a migration and a proliferation of both cell populations.

Animals↗
PubMed1985

Effect of attempted lifting speed on forces and torque exerted on the lumbar spine.

Factors affecting compressive and shear forces and torque at the L5/S1 vertebral joint were examined for nine different load/lifting-speed combinations during performances of a dynamic lifting task by 10 subjects. Loads were 40, 60, and 80% of each subject's maximum lifting capability. Target lifting times were 1.5, 3.5, and 7 s. A rigid link model of the human body was used to derive estimates of axial force, shear force, and torque acting at the L5/S1 vertebral joint from high-speed film data. Variables examined empirically were myoelectric activity at the fifth lumbar level of sacrospinalis and intra-abdominal pressure. The respective effects of load and attempted lifting time were assessed through two-factor ANOVA's and subsequent Scheffé tests. Heavier loads were found to result in significantly higher (P less than .001) values of mean compressive force, mean shear force, and maximum myoelectric activity. Faster target lifting times resulted in significantly higher mean and maximum values of all the variables quantified except intra-abdominal pressure.

Adult↗
PubMed1981

Metacarpophalangeal flexion forces with respect to age, sex, and exercise habits.

Individual finger strengths in digits II-V were examined in terms of metacarpophalangeal (MP) joint flexion forces among a group of 22 senior citizens. Data were collected using a finger force transducer, with each digit splinted so as to allow flexion solely at the MP joint. Findings were evaluated in light of the self-reported exercise habits of the subjects and in comparison with similar data reported in a previous study conducted with college athletes. Patterns of finger strength among the digits and between the sexes were identical for most parameters investigated among the senior citizens as compared to the college athletes. Mean finger strength levels for male and female senior citizens were 10.0% and 10.5% less, respectively, than those of the college athletes of each sex. Correlations between individual estimates of hours spent per week engaged in activity requiring extensive hand utilization and mean finger strength for each subject were r = 0.14 and r = 0.46 for male and female subjects, respectively.

Adult↗
PubMed1971

Tetrameric immune macroglobulins in three orders of bony fishes.

The immune IgM-like macroglobulins were isolated from three species of bony fishes (Ictalurus punctatus, Lepisosteus osseus, and Polyodon spathula) representing the three orders of the subclass Actinopterygii. These macroglobulins were found to have sedimentation coefficients of 14 S and molecular weights of 600,000-630,000. The carbohydrate compositions were determined and found to be different from that of human macroglobulins. After reduction and alkylation, the heavy and light chains could be separated by gel filtration and were found to have molecular weights of approximately 70,000 and 23,000 respectively. The amino acid compositions of these chains were similar to those of mammalian IgM heavy and light chains. The macroglobulins were found by electron microscopy to have a tetrameric structure, in contrast to the pentameric structure found in mammalian, chicken, and shark IgM, i.e. in species later on the evolutionary scale.

Amino Acids↗
PubMedDate not supplied

Cooperative therapeutic effects of androgen ablation and adenovirus-mediated herpes simplex virus thymidine kinase gene and ganciclovir therapy in experimental prostate cancer.

Adenovirus-mediated transduction of the herpes simplex thymidine kinase gene (HSV-tk) in conjunction with ganciclovir (GCV) has been shown to result in significant growth suppression and to enhance survival in a model of mouse prostate cancer. However, this therapeutic activity is not sustained, because in most cases tumors eventually regrow and ultimately cause the death of the host. Androgen ablation, an inducer of apoptosis in prostate cells which is used widely as palliative therapy in patients with prostate cancer, was combined with HSV-tk plus GCV using an androgen-sensitive mouse prostate cancer cell line. The combination of castration and HSV-tk plus GCV led to markedly enhanced tumor growth suppression in both subcutaneous and orthotopic models compared with either treatment alone and resulted in an enhanced survival in which combination-treated animals lived twice as long as controls in the subcutaneous model and over 50% longer than controls in the orthotopic model. Further analysis of apoptotic activity demonstrated high levels of apoptosis only in combined androgen ablation and HSV-tk plus GCV-treated tumors after 14 days of growth in an androgen-depleted environment and 8 days after HSV-tk plus GCV therapy. At this time, the apoptotic index, but not the percent of necrotic tissue, was significantly higher for combination therapy-treated tumors relative to control-treated tumors or either treatment alone. These data indicate that the therapeutic effects of androgen ablation and HSV-tk plus GCV are cooperative and that increased apoptosis may, in part, underlie these activities.

Adenoviridae↗