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Biomedical subjects

S Simon

Publications and source records attributed to S Simon.

At least 127 records · Page 7Linked to original sources
PubMed1987

Gait disorder in late-life hydrocephalus.

Computerized analysis of gait was performed in six patients with hydrocephalus (mean age, 75.7 years), for comparison with other elderly patients with gait problems and age-matched controls. A decrease in velocity and stride, an increase in sway, and the proportion of time spent in double-limb stance were nonspecific features correlated with declining performance. Certain features appeared to characterize hydrocephalic gait when compared among groups; cadence was diminished, and there was a reduction of step height and a decreased counterrotation of the shoulders relative to the pelvis. An abnormal tendency toward cocontraction in antagonist muscle groups was observed in electromyographic data from the leg muscles, suggesting that the normal phased activation of muscle groups is disturbed. Although data are not conclusive, we believe that the gait disorder in normal-pressure hydrocephalus reflects a subcortical motor control disorder rather than a phenomenon of spasticity or apraxia.

Aged↗
PubMed1987

Avascular necrosis of the femoral head: early MRI detection and radiological correlation.

Magnetic Resonance Imaging (MRI) and conventional radiographs were compared in 49 hips with Avascular Necrosis (AVN). MRI detected AVN in 25% of the hips during the preradiological stage of the disease. Both MRI and conventional radiographs accurately detected AVN in the remaining 75% of hips. Correlation between the patterns observed with the two techniques reflected the underlying histopathologic events. The reactive interface between infarcted bone and viable bone could be identified on MRI as a low signal intensity (SI) band. On conventional radiographs the reactive interface appeared as a sclerotic band. The adjacent hyperemic zone was seen on MRI as a high SI band and as a lucent zone on the plain films. Variations of this pattern occurred as related to the extend and duration of AVN and to the individual's ability to mount a healing response. Minor degrees of collapse of the femoral head were better identified with plain radiographs but MRI demonstrated small areas of hyperintensity probably corresponding to early subchondral fractures.

Femur Head Necrosis↗
PubMed1987

A controlled double-blind study of high-dose dihydroergotoxine mesylate (Hydergine) in mild dementia.

In a double-blind study of 41 outpatients aged 55 to 80 years with mild memory impairment, the efficacy of dihydroergotoxine mesylate (DEM, Hydergine) at 6 mg per day, administered orally, was tested during a twelve-week period. Specific etiologies for the amnesic syndrome were ruled out by history, physical examination, and laboratory tests. Subjects with a Hamilton Depression Scale rating above 18, ie, possible pseudodementia, were excluded. Physician rating of memory, employing the Inventory of Psychic and Somatic Complaints in the Elderly (IPSC-E), indicated statistically significant improvement of memory function in DEM treated subjects (N = 22) v those on placebo (N = 19), (F = 3.34; df = 1,39; P less than .04). In contrast, structured testing of recent memory using digit symbol substitution and Zahlenverbindungs test (ZVT) showed improvement in both groups (P less than .001) with no significant intergroup differences (P less than .10). Out results indicate that in cases of mild, though subjectively distressing impairment, DEM at higher dosages may help to enhance short-term memory function.

Affect↗
PubMed1987

cDNA cloning with a retrovirus expression vector: generation of a pp60c-src cDNA clone.

We used a murine retroviral expression vector, containing a genomic clone of the chicken c-src gene, a bacterial origin of replication, and a selectable marker, to remove 10 introns from the c-src gene. All 10 introns were removed accurately, and no mutations were introduced. The processed gene encoded a functional pp60c-src protein tyrosine kinase.

Cloning, Molecular↗
PubMed1985

Erythema nodosum heralding recurrent Hodgkin's disease.

The association of erythema nodosum with Hodgkin's disease is acknowledged, although not well-documented in the literature. Two patients with long remissions of their Hodgkin's disease manifested persistent erythema nodosum beginning 7 and 6 months, respectively, before relapse was clinically evident. The skin lesions in both patients partially responded to treatment with indomethacin, but did not resolve completely until chemotherapy was instituted. Erythema nodosum probably reflects an important change in the balance of biologic forces between the host and the neoplasm, the nature of which can only be speculated upon at this time. Erythema nodosum should be considered a warning signal of impending relapse in a patient with a history of Hodgkin's disease.

Adolescent↗
PubMed1985

Polyomavirus middle T protein encoded by a retrovirus transforms nonestablished chicken embryo cells.

A murine retrovirus encoding the middle T protein of polyomavirus infected and transformed nonestablished chicken embryo cells. The infected cultures formed colonies in soft agar-containing medium and released infectious transforming virus. Middle T protein expressed in the transformed chicken cells associated with p60c-src and, in immunoprecipitates, enhanced the tyrosine protein kinase activity of p60c-src.

Animals↗
PubMed1985

[Serological response of the dog after primary antirabies vaccination using adjuvant or non-adjuvant vaccines].

The serological responses following a primary vaccination carried out one year before in two groups of dogs which received an inactivated cell culture vaccine containing or not an adjuvant (alumine-hydroxide) are compared. Neutralizing antibody titers assayed in mice, obtained with only one injection of the adjuvanted vaccine are at the same or a greater level than those induced by two injections of the non-adjuvanted vaccine administered two to four weeks apart (statutory schedule of rabies primary vaccination applied in France).

Adjuvants, Immunologic↗
PubMed1983

Interstitial fluid pressure changes in pregnant rats.

In pregnant rats significant interstitial fluid pressure changes could be detected by means of capsules chronically implanted into the subcutaneous tissue. The capsular pressure increased significantly from a control value of -4.3 +/- 0.5 mmHg to -0.7 +/- 0.5 mmHg during the first period of pregnancy. Immediately before parturition the capsular pressure returned to the control level. During lactation the pressure rose as high as + 0.5 +/- 0.9 mmHg. After lactation the pressure returned again to the control value. By determining the extracellular fluid and plasma volume, as well as protein concentration in plasma and capsular fluid, the hydrostatic and colloid osmotic forces operating in the extracellular space could be analysed. It has been concluded that the observed capsular pressure changes during pregnancy are not solely of volumetric or colloid osmotic origin.

Animals↗
PubMed1982

[Recent experiences with kidney explantation outside transplantation centers].

The ever-increasing negative balance between the offer of an demand for organs with regard to transplantation surgery is very problematic. The transplantation centres are confronted with an insolvable problem and for this reason the co-operation of hospitals, other than the transplantation centres, is of vital importance where the explantation of kidneys, under specified conditions, is concerned. There are reports of new experiences in the removal of organs through in-situ-perfusion and en-bloc-removals as well as combined consignments of organs and typing material. The favourable results personally achieved during the past 6 years have given cause to believe that other clinics or hospitals, other than the transplantation centres, will participate in the explantation or organs for the purpose of transplantation.

Brain Death↗
PubMed1981

The kinetics of ionophore X-537A-mediated transport of manganese through dipalmitoylphosphatidylcholine vesicles. A 1H-NMR study.

We have studied the kinetics of ionophore X-537A-mediated transport of manganese ions into small unilamellar vesicles formed from dipalmitoylphosphatidylcholine. To follow the transport we used the paramagnetic effect of manganese on the 1H-NMR signal from choline trimethylammonium groups on the inner phospholipid monolayer. The transport of only one manganese ion produces an intravesicular concentration which is high enough (approx. 1 mM) to substantially broaden this signal. The observed signal thus arises predominantly from those vesicles which contain no manganese. Therefore, as manganese is transported into the vesicles the observed signal decreases in intensity, but does not broaden. The initial time-dependence of the intensity of the signal, S(t), can be approximated by the simple first-order rate law: S(t) = S(0) exp(-k't), where k' is the probability per unit time for the transport of a manganese ion from the external medium to the intravesicular space. From the dependence of k' on the ionophore X-537A concentration we conclude that manganese is transported into the vesicles via both 1 : 1 and 2 : 1 complexes with ionophore X-537A. At low ratios of ionophore X-537A to vesicles transport via the 1 : 1 complex predominates; at high ratios transport via the 2 : 1 complex predominates. From the dependence of k' on manganese concentration we determined that under our conditions the equilibration of ionophore X-537A between vesicles is much faster than the transport of manganese through the vesicles. Lastly, from the dependence of k' on temperature, we conclude that the ionophore X-537A-mediated transport of manganese into the dipalmitoylphosphatidylcholine vesicles is very sensitive to the gel-liquid crystalline phase transition.

Kinetics↗
PubMed1981

Effects of [Na+], [Cl-], carbonic anhydrase, and intracellular pH on corneal endothelial bicarbonate transport.

Sodium removal from the solution bathing the isolated rabbit corneal endothelium caused a reduction in both unidirectional and net flux of bicarbonate, whereas chloride withdrawal from the solution had no effect on the net bicarbonate flux but increased the unidirectional fluxes. These data correlate with previously published data on the effects of similar solution manipulations on both fluid movement and potential difference across the endothelium and strongly implicate bicarbonate as the primary ion involved in the maintenance of corneal hydration. Carbonic anhydrase (1 mg/ml) added to the solution bathing both sides of the endothelium markedly increased unidirectional and net bicarbonate fluxes, possibly by maintaining a high bicarbonate/CO2 concentration close to the membrane and thereby eliminating chemical gradients in the unstirred layer adjacent to the membrane. Determinations of intracellular pH with the 5,5-dimethyl-2,4-oxazolidine-dione method indicate that at more acid ambient conditions there is a lesser gradient between cell and bathing medium for H+; similar ambient conditions in other experiments resulted in larger unidirectional bicarbonate fluxes than at neutral pH. The data are suggestive of a nonvectorial H+-HCO3- exchange occurring across the endothelial cellular membranes.

Animals↗