Direct current control of three magnon scattering processes in spin-valve nanocontacts.

We have investigated the generation of spin waves in the free layer of an extended spin-valve structure with a nanoscaled point contact driven by both microwave and direct electric current using Brillouin light scattering microscopy. Simultaneously with the directly excited spin waves, strong nonlinear effects are observed, namely, the generation of eigenmodes with integer multiple frequencies (2f, 3f, 4f) and modes with noninteger factors (0.5f, 1.5f) with respect to the excitation frequency f. The origin of these nonlinear modes is traced back to three-magnon-scattering processes. The direct current influence on the generation of the fundamental mode at frequency f is related to the spin-transfer torque, while the efficiency of three-magnon-scattering processes is controlled by the Oersted field as an additional effect of the direct current.

Observation of coherence and partial decoherence of quantized spin waves in nanoscaled magnetic ring structures.

Experiments and simulations are reported, which demonstrate the influence of partial decoherence of spin-wave modes on the dynamics in small magnetic structures. Microfocus Brillouin light scattering spectroscopy was performed on 15 nm thick Ni81Fe19 rings with diameters from 1 to 3 microm. For the so-called "onion" magnetization state several effects were identified. First, in the pole regions of the rings spin-wave wells are created due to the inhomogeneous internal field leading to spin-wave confinement. Second, in the regions in between, modes are observed which show a well pronounced quantization in radial direction but a transition from partial to full coherency in azimuthal direction as a function of decreasing ring size. In particular for larger rings a continuous frequency variation with position is observed which is well reproduced by spin-wave calculations and micromagnetic simulations.

Immunity to measles before and after MMR booster or primary vaccination at 12 years of age in the first generation offered the 2-dose immunization programme.

In 1982, a 2-dose regimen was introduced in Sweden for the combined vaccination against measles, mumps and rubella (MMR) in children aged 18 months and 12 years. In 1993, blood samples from 378 12-year-old children, i.e. the first age-group receiving a MMR booster, were collected prior to and 2 months after the vaccination. 82% had a certificate of a previous measles (M) or MMR vaccination (group I). The remainder was classified as children with 'no documentation' (group II). In group I, 5 (1.5%) lacked demonstrable antibodies to measles prior to the booster; in group II this figure was 39%. The pre-booster antibody pattern was similar in M vaccinees and MMR vaccinees. After the vaccination, 1 of the 378 children was seronegative. In both groups, children with low pre-vaccination levels responded with a titre rise, in accordance with a similar study 6 years earlier.

Improved cell-mediated immune responses in HIV-1-infected asymptomatic individuals after immunization with envelope glycoprotein gp160.

Strong specific T-cell responses to human immunodeficiency virus type 1 (HIV-1) gp160 were induced by immunization with recombinant gp160 (rgp160). It was given as postinfection vaccination to 40 asymptomatic HIV-1 seropositive patients. The participants received 6 doses of 160 micrograms rgp160 administered intramuscularly at 0, 1, 4, 8, 17, and 26 weeks and were monitored for 1 year. Lymphocyte proliferation was performed by cultivating lymphoid cells in vitro with specific antigens and mitogens. After immunization with gp160, specific T-cell proliferative responses were induced in all 40 patients. One week after the sixth immunization at day 180, a substantially increased response was detected in 98% of the patients, with a mean stimulation index value of 195. Furthermore, proliferative responses were also identified, after immunization, against native gp120 and against a peptide representing the V3 region of gp120. In addition to the HIV-specific T-cell responses, increased reactivity to several other non-HIV antigens, including tetanus toxoid, influenza, measles, and cytomegalovirus, were seen after gp160 vaccination. The responses to CMV and measles were interpreted to represent an improved recall antigen response. Such recall antigen responses were few in matched HIV-infected controls immunized with influenza virus only. All patients initially and repeatedly showed a normal capacity of total T-cell activation, evaluated by the mitogen phytohemagglutinin (PHA). The trend in CD4 counts improved in 30 of 40 patients during the year of follow-up. The frequency of increases of proliferative responses to antigens was associated with a better CD4 trend. Addition of zidovudine for 2 weeks after each immunization had no beneficial effects nor did it prevent induction of immune responses. All patients tolerated the immunizations well, and no systemic adverse effects were noted. This is a phase I trial, and no definitive conclusions regarding clinical efficacy can be reached.

[Normal pressure hydrocephalus in geriatric patients--a treatable form of dementia]. / Normaldruckhydrozephalus bei geriatrischen Patienten--eine behandelbare Form der Demenz.

Six geriatric patients are presented who were treated because of normal pressure hydrocephalus. A tentative diagnosis was made if dementia, gait disturbance, and incontinence together with a typical CAT-scan were present. In these cases an operation was carried out. After ventriculo-peritoneal shunting clinical improvements were seen in four patients. Postoperative complications were hygromas in three patients and a shunt-dislocation in another patient. A chronic subdural bleeding was recorded also in one of these patients with only a temporary success in this case. Two patients showed no clinical improvement at any time. However, in these cases additional neurologic symptoms together with typical CAT-scan changes were present. Before making a decision for an operation vascular processes and Alzheimer's disease should be ruled out.

Comparative methods for detection of thymidine kinase-deficient herpes simplex virus type 1 strains.

Four methods for analyzing viral susceptibility to antiviral substances were compared. In two methods viral products were measured: late viral proteins were measured by an enzyme-linked immunosorbent assay and viral DNA was measured by DNA hybridization. Infectious virus was quantified in the other two assays as the number of plaques and the yield of virus. The enzyme-linked immunosorbent assay procedure in our hands detected the smallest amounts (lowest proportions) of thymidine kinase-deficient herpes simplex virus type 1 mixed with wild-type virus. The thymidine kinase-deficient proportion of the herpes simplex virus type 1 isolate increased rapidly in the presence of acyclovir in cell culture.

Multiplicity dependence and sensitivity of herpes simplex virus isolates to antiviral compounds.

An immunoassay that enables one to assess both viral multiplicity and sensitivity to antiviral drugs, was used to determine the sensitivity of untreated patients' virus isolates. The upper border levels for judging clinical isolates sensitive to Ara-A, ACV, PFA or IDU were calculated from a total of 48 primary herpes simplex isolates. Although five isolates were considered less sensitive to one drug and one isolate to two drugs, all were sensitive at a lower virus multiplicity. Analysis of these isolates showed that no isolate was genetically resistant, but that multiplicity dependence of drugs was high with ACV and Ara-A, lower with PFA. In view of the multiplicity dependence of HSV sensitivity to different drugs, it is recommended that isolates from treatment failures or isolates considered resistant should be assayed in detail.

A novel method for determining the sensitivity of herpes simplex virus to antiviral compounds.

A rapid and sensitive assay was developed to analyse the sensitivity of wild type HSV-1 and HSV-2 isolates with respect to a battery of antiviral substances. In the viral sensitivity assay, human embryonic lung fibroblasts are incubated with the virus isolate and different concentrations of the antivirals. After 1-3 days, the cells are disrupted and analysed for HSV type 1 or 2 antigens by an enzyme-linked immunosorbent assay. Antigens corresponding to 17 plaque-forming units were detectable after 1 day of incubation. After 3 days, HSV antigens derived from less than one plaque-forming unit were measurable. The sensitivities of 22 HSV-1 and 19 HSV-2 primary isolates from untreated patients were tested against adenosine arabinoside, acyclovir, phosphonoformic acid and iododeoxyuridine. Each isolate was found to have an individual pattern of sensitivities to the different antivirals. Five isolates were judged to be relatively resistant to one or more of the drugs tested.

[Idiopathic polyneuritis. Course, prognosis and electrodiagnostic findings]. / Die idiopathische Polyneuritis. Verlaufsformen, Prognose und elektrodiagnostische Befunde.

In acute idiopathic polyneuritis, the slowing of nerve conduction velocity does not allow prognostical statements. However, a marked reduction of muscle potential amplitude after stimulation and recording points implies a large number of damaged axons. This effect occurs earlier and is more reliable than pathological spontaneous activity in the EMG. Following complete or almost complete loss of indirect muscle excitability, improvement of function can be expected only after sprouting of nerve fibers--therefore after some months at best; permanent defects must bei anticipated especially in distal muscle groups. We experienced this most commonly--but not exclusively--in cases with highly acute courses which led to tetraparalytic syndroms. Clinical courses with slowly progressive disease during months and recurrent courses of idiopathic polyneuritis can also lead to permanent paresis.

[McArdle's disease--description based on three own observations (author's transl)]. / Das McArdlesche Syndrom--Darstellung anhand von drei eigenen Beobachtungen.

The paper reports on three observations made by the authors of McArdle's Disease. Characteristic symptoms are a premature tiring of the musculature and painful muscle contractions; in the late stage of the disease, mild muscle atrophy can also occur. The ischemia test is is pathologic. Myoglobinuria often occurs after major strain. Studies by light microscope and the electron-microscope result in an increased glycogen deposit in the muscle fiber. The diagnosis is verfied by the histochemical and biochemical proof of muscle phosphorylase deficiency. Routine histologic investigation of muscle biopsy is not sufficient to identify the disease. Despite the established enzyme defect and the resulting impairment of anerobic energy availability, the genesis of the disease or syndrome has not yet been fully clarified.

[Lesions of the peripheral nerves in Wilson's disease. Electrodiagnostic findings (author's transl)]. / Beeinträchtigung des peripheren Nervensystems bei der Wilsonschen Krankheit. Elektrodiagnostische Befunde.

Electrodiagnostical studies were carried out on three patients with Wilson's disease. The motor nerve conduction velocity was low but not markedly decreased. Some values of the sensory conduction velocity were decreased; the sensory action potentials showed low amplitudes and contained large amounts of late phases. Also, the electromyogram of one female patient showed denervation in the begin of treatment. There are no indications of polyneuropathy in Wilson's disease in the literature. There have been histological reports, however, which indicated lesions of the peripheral nerves in Wilson's disease as our own electrodiagnostical findings do.

HLA frequencies in primary immunodeficiency diseases (pidd).

Thirteen patients with primary immunodeficiency disorders and their twenty-five healthy first-degree relatives were tissue typed and their HLA make-up was compared with that of a normal control population. HLA-A2 occured in 92.3% of patients as opposed to 60.8% in the control group (P less than 0.02), HLA-A9 in 7.6% vs. 25% (P less than 0.02) and HLA-B8 in 0% vs. 21% (P less than 0.04). One of the patients with severe combined immunodeficiency showed one "extraneous" HLA specifity.

[Clinical electrodiagnostic findings in peroneal muscular atrophy (author's transl)]. / Klinische und elektrodiagnostische Befunde zur neuralen Muskelatrophie

43 patients and 27 relatives suffering from a hypertrophic type of peroneal muscular atrophy have been examined. Following the classification of peroneal muscular atrophy by Dyck and Lambert early age of onset and considerable reduction of nerve conduction velocity served as criteria for allotting them to the hypertrophic type. In all patients a typical deformity of the foot developed before the age of 10. Among the relatives there were some without this deformity and with only slight clinical signs. Assessing consistency and thickness of peripheral nerves by palpation proved difficult and unreliable. These findings also varied considerably between members of one family. The motor nerve conduction velocity was less than one half of the normal on average. Even those patients with only minor clinical signs had a nerve conduction velocity reduced by one fifth. In about 60% of the patients there was dominant inheritance, in 3 it was recessive and in about one third nothing was known. 10 of the patients without dominant inheritance had rather severe neurologic disturbance and a kyphoscoliosis. Whether this is hypertrophic neuritis of Dejerine und Sottas is discussed. Data form the literature differ. Another common type of peroneal muscular atrophy is the neuronal type. In contrast to the hypertrophic type it generally begins in adults and nerve conduction velocity is hardly affected.

[N. interosseous anterior syndrome. Study in 4 cases of our own and in 49 cases from the literature (author's transl)]. / N. interosseus anterior-Syndrom. Bericht über 4 eigene und 49 Fälle aus der Literatur

The anterior interosseous nerve branches off from the median nerve distal of the pronator radii teres. It lies on the interosseous membrane, always innervates the flexor pollicis longus, usually the portion of the deep flexor belonging to the second, sometimes also the portion belonging to the third finger, then runs to the pronator quandratus. In 4 cases of our own and in 49 cases from the literature we could show that an isolated lesion of the motor division of the median nerve has been seen after fractures and in connection with dull traumas, unusual activities, pressure and medical procedures. A mechanical origin can be assumed also in the so-called "spontaneous" cases of paresis without any indication of exogenous influence. It is described twice as often on the right as on the left side and in 15 of 17 cases of operative revision fascial bands, adhesions, and similar compressions were found. Frequently, the only sign of the syndrome is paresis of the flexor pollicis longus. The diagnosis becomes clearer, when the flexor digitorum profundus is also affected, since the extension of the first two or three end phalanges during flexion of all fingers constitutes a characteristic clinical feature. Occasionally, pain is present on the outside of the forearm, and this can lead to differential diagnostic reflections. In spite of the convincing operative findings we find that the experience to date is not sufficient to give a general recommendation for operative treatment. The prognosis is favorable, apparently even without operative revision; in some cases, however, as in one of our patients, the paresis does not improve until the second year after onset.

[On the vocational prognoses of patients with peroneal muscular atrophy (author's transl)]. / Zur Berufsprognose bei Patienten mit einer neuralen Muskelatrophie

Examined were 43 patients and 27 relatives all suffering from a hypertrophic type of peroneal muscular atrophy. Owing to foot deformities and a slowing of the nerve conduction velocity a diagnosis was already possible in their childhoods in the majority of cases. Although, after the 20th year of age, the pareses of the legs progress only slowly, considerable pareses of the small hand muscles can still develop in adults. With adequate counselling, rehabilitation measures should become necessary only in rare cases, or, if a kypho-scoliosis has already developed in childhood (10% of our cases).

["Fatiguability" in myasthenic syndromes]. / "Ermüdungsreaktion" bei myasthenischen Syndromen

Neuromuscular disorders accompanied by a "myasthenic reaction", but without other symptoms of myasthenia gravis and no therapeutic response to cholinergic drugs may be called myasthenic syndromes. The abnormal fatigability can be shown in the electromyogram. Lasting voluntary contraction of a muscle shows a rarefication of the EMG-pattern. Sometimes during repetitive stimulation of the motor nerve a decrease in the amplitude of the muscle potential may occur. This decrease is poorly influenced by cholinergic drugs. Often this observation was present in patients with myositis and myotonic dystrophy, sometimes in other myopathies and seldom in neurogenic disorders. A failure in the neuromuscular transmission is discussed not only in myasthenia gravis, but also in myasthenic syndromes. But there may be another explanation. A decreased number of intact muscle fibers during lasting innervation will cause a more rapid fatigation of the muscle fibers and in this way there will be an exhaustion. It is discussed, whether the symptoms in myasthenic syndromes can be explained by an abnormal "fatigability".