Cervico-thoracic disc protrusions in controlled compressed-air diving: clinical and MRI findings.

Prevalence of cervical and thoracic disc protrusions was investigated by MRI in 24 military long-term compressed-air divers and 24 controls. A total of 26 disc protrusions (17 cervical disc protrusions) were detected in 58% of the divers whereas 18 protrusions were detected in 38 % of the controls (13 disc cervical protrusions). There was no significant difference between groups and no correlation with the diving experience. Neurological examination revealed no clinical abnormalities. In contrast to a recent study, our results suggest that long-term divers are at no increased risk for accumulating spinal disc protrusions or intramedullary abnormalities.

Neurologic outcome of controlled compressed-air diving.

The authors compared the neurologic, neuropsychological, and neuroradiologic status of military compressed-air divers without a history of neurologic decompression illness and controls. No gross differences in the neuropsychometric test results or abnormal neurologic findings were found. There was no correlation between test results, diving experience, and number and size of cerebral MRI lesions. Prevalence of cerebral lesions was not increased in divers. These results suggest that there are no long-term CNS sequelae in military divers if diving is performed under controlled conditions.

Physician-diagnosed erythema migrans and erythema migrans-like rashes following Lone Star tick bites.

OBJECTIVE: To differentiate cases of physician-diagnosed erythema migrans and erythema migrans-like rashes associated with Lone Star tick (Amblyomma americanum) bites. DESIGN: Retrospective case series. SETTING: Private primary care clinic in rural Missouri. PATIENTS: Seventeen patients with physician-diagnosed erythema migrans following a definite Lone Star tick bite at the rash site. INTERVENTIONS: A biopsy was performed on all rash sites. All patients were treated with oral antibiotics. MAIN OUTCOME MEASURES: Rash appearance, size, body location, multiple lesions, incubation times, associated symptoms, seasonal occurrence, histopathological features, tick stage and sex, patient age and sex, treatment response, growth in BSK II culture media, and serologic evaluation. RESULTS: Rashes associated with Lone Star ticks were similar to erythema migrans vectored by other Ixodes ticks. Differences were noted in Lyme disease serology results, especially flagellin-based enzyme immunoassays, and failure to yield spirochetes in BSK II cultures. Lyme serology results were often negative, but were also frequently inconsistent with results of controls without Lyme disease. CONCLUSIONS: Lone Star ticks are associated with rashes that are similar, if not identical, to erythema migrans associated with borrelial infection. The recent isolation and cultivation of Borrelia burgdorferi from ticks (including 1 Lone Star tick) from the farm of a patient included in this report has raised the possibility that Lone Star ticks are "bridge vectors" for human borrelial infection. Although further investigation is needed, these rashes may be secondary to spirochetal infection.

[Transcranial magnetic stimulation as an alternative to electroshock therapy in treatment resistant depressions. A literature review]. / Die transkranielle Magnet-stimulation als Behandlungs-alternative zur Elektrokrampf-therapie bei therapieresistenten Depressionen--Eine Literaturübersicht.

Transcranial magnet stimulation (TMS) is a low-risk method for direct and localised stimulation of the cerebral cortex. For several years it has played an important part in measurements of the central motor conduction time (magnetically evoked potentials/MEP). Further technical and methodological developments, such as high-frequency (rapid rate TMS/rTMS) or triggered stimulation have led to broad scientific application of this method. Electric convulsive therapy (ECT) has proved its value in the treatment of various psychiatric disorders, especially in pharmaco-resistant depression. The therapeutic mechanism is actually unclear. However, the generalised convulsive fit appears to be the precondition for the therapeutic effect. A disadvantage lies in the risk inherent in the necessary general anaesthesia and the possible side effects, such as transitory states of confusion and transient mnestic deficits. Bearing in mind the possibility that TMS could have the same effects as ECT due to stimulations below the convulsion threshold or to the direct or indirect stimulations of so-called disorder-specific key regions, several pilot studies and some controlled studies have been published during the past three years on its efficacy in depressive disorders. The results were reported on and critically evaluated. The results of this survey of the literature on the subject is that (r)TMS does not represent an alternative to ECT in the therapy of pharmaco-resistant depressions. Due to its slight and only transient antidepressive effect, (r)TMS is also, in our opinion, not suitable as so-called add-on therapy as a complement to antidepressant medication.

Circadian variation of pain sensitivity in pericranial musculature.

This study investigated whether pain sensitivity of the pericranial musculature remains constant over the course of the day. Changes in the entire, uniformly metrically divided suprathreshold sensitivity range were measured. In 24 healthy volunteer subjects, pain was induced experimentally at 0200, 0600, 1000, 1400, 1800, and 2200 hours in the pericranial musculature. Blood circulation in both superficial temporal and occipital arteries was reduced by applying a cuff to the head pumping up to 200 mmHg during rhythmic chewing on a spring, thereby producing a continuously increasing bilateral, dull, frontal headache. The subjects rated the intensity continuously using a category sub-dividing procedure ranging from pain threshold to pain tolerance limit. At low levels of headache intensity there were no significant diurnal differences in pain sensitivity. Sensitivity to very intense headache, however, varied significantly over the course of the day: sensitivity was greatest at 0200 hours; it decreased at a constant rate until 1400 hours, and increased again continuously until 2200 hours (p less than or equal to .05). Also the findings showed significant effects of sex on the pain sensitivity of pericranial musculature for all pain intensities: women are approx. twice as sensitive as men (p less than or equal to 0.05). These results suggest that not only sex, but also time of day, must be taken into consideration in the clinical determination of pain sensitivity of pericranial musculature in the course of headache diagnostics.

Recombinant human bone morphogenetic protein induces bone formation.

We have purified and characterized active recombinant human bone morphogenetic protein (BMP) 2A. Implantation of the recombinant protein in rats showed that a single BMP can induce bone formation in vivo. A dose-response and time-course study using the rat ectopic bone formation assay revealed that implantation of 0.5-115 micrograms of partially purified recombinant human BMP-2A resulted in cartilage by day 7 and bone formation by day 14. The time at which bone formation occurred was dependent on the amount of BMP-2A implanted; at high doses bone formation could be observed at 5 days. The cartilage- and bone-inductive activity of the recombinant BMP-2A is histologically indistinguishable from that of bone extracts. Thus, recombinant BMP-2A has therapeutic potential to promote de novo bone formation in humans.

[Algesimetric experiment on pain sensitivity in the pericranial musculature. Circadian rhythms and corresponding psychic variables.]. / Die schmerzempfindlichkeit der perikranialen muskulatur im algesimetrischen experiment : Zirkadiane Rhythmik und korrespondierende psychische Variablen.

Many types of headache that occur in the form of attacks show a notably high incidence at certain times of the day. Attacks are often accompanied by emotional instability, irritability, exhaustion and other impairments of well-being. The cause for the frequent daytime occurrence of attacks is not clear. One possible explanation could be the variability in a person's sensitivity to headache over the course of the day. For this reason we set out to investigate whether pain sensitivity to experimentally-induced headache varies in a circadian manner and whether this variation correlates to changes in the current state of well-being over the course of the day. In 24 healthy, voluntary subjects, headache was induced experimentally at 0200, 0600, 1000, 1400, 1800, and 2200 hours. Blood criculation in both superficial temporal and occipital arteries was reduced by applying a cuff to the head and inflating it to 200 mmHg, thereby producing a continuously increasing, bilateral, dull, frontal headache. The subjects scaled the intensity continually, using the category subdividing procedure ranging from pain threshold to pain tolerance level. In addition, 17 dimensions of the current state of well-being and 12 personality traits were recorded at the above-mentioned times in a standardized quantitative manner. At low levels of headache intensity there were no significant differences in pain sensitivity. Sensitivity to very intense headache, however, varied significantly over the course of the day: sensitivity was greatest at 0200 hours; it decreased at a constant rate until 1400 hours, and increased again continuously until 2200 hours (P

Purification and molecular cloning of a novel group of BMPs and localization of BMP mRNA in developing bone.

Using a novel purification scheme, we have characterized BMP as a 30kD fraction. After reduction, which destroys biological activity, this fraction was shown to be comprised of individual polypeptides with molecular weights of 30kD, 18kD and 16kD. Molecular cloning of these polypeptides resulted in the identification of 4 previously undescribed genes (BMP-1, BMP-2A, BMP-2B, and BMP-3) each of which is capable of directing de novo cartilage formation in vivo. While BMP-1 appears to be unrelated to other known growth factors, the derived amino acid sequence of BMP-2A, 2B, and 3 indicate that they are new members of the TGFb gene family. BMP-1, 2A and 2B are expressed in rat embryos during morphogenesis and can be localized by in situ hybridization to developing limb buds. BMP-3 localizes to neural ectoderm and later on in development to newly forming periosteum. Comparisons to other members of the TGFb family suggest that these newly identified BMPs are involved in pattern formation during early skeletal development.

Purification and characterization of other distinct bone-inducing factors.

We purified a factor that induces bone formation greater than 300,000-fold from guanidinium chloride extracts of demineralized bone. Fifty nanograms of highly purified protein was active in an in vivo cartilage and bone-formation assay. The activity resided in a single gel band, corresponding to a molecular mass of approximately 30 kDa, which yielded proteins of 30, 18, and 16 kDa on reduction. The partial amino acid sequence obtained from these proteins confirmed our identification of specific factors that induce new bone formation in vivo.

Transposon tagging to detect a latent virus in Myxococcus xanthus.

Transposon mutagenesis of the bacterium Myxococcus xanthus with the transposon Tn5 revealed a special class of bacterial mutants that transduced the transposon through culture supernatant fluids. Virus-like particles copurified with transducing activity. Transposon tagging for detecting these virus-like particles may be generally useful in isolating endogenous viral agents capable of transferring genetic information between cells.