Liberation of hydrogen from gastric acid following administration of oral magnesium

We are in the process of developing a noninvasive test for gastric acid secretion based on the reaction of orally administered magnesium metal with gastric acid: Mg + 2HCl in equilibrium with MgCl2 + H2. We hypothesized that the hydrogen gas thus evolved could be detected in exhaled air and belches and that the amount of hydrogen released could be related to the amount of acid in the stomach. To validate this hypothesis, we gave magnesium to two groups of young adult volunteers following either betazole stimulation or cimetidine inhibition of acid secretion. In group I we gave subcutaneous betazole and gave magnesium in doses from 10 to 200 mg. In group II we gave oral betazole and used a constant dose of 150 mg of magnesium. In both groups we consistently detected significant increases in breath and belch hydrogen following magnesium in the betazole-stimulated volunteers. This response was blocked by cimetidine. The magnitude of the response was related to the magnesium dose, with 150 mg appearing to induce a maximum response. Administration of oral magnesium up to 200 mg was not associated with any untoward effects. We conclude that magnesium led to the release of hydrogen gas in vivo and that the quantity of hydrogen gas recovered was related to the amount of gastric acid. With further development, this principle might be used to develop a simple noninvasive test for gastric acid secretion.     

Radiotherapy of brain metastases (author's transl)]

Brain metastases of malignant extracranial tumors are usually multiple. Very often they require an effective palliative treatment. Radiotherapy of the entire cranium produces improvement of the neurological and psychic symptoms in 80-90% of the patients. The survival time cannot be extended by this treatment. There is no optimum radiation scheme. Indications for the surgical removal of brain metastases are tabulated.     

Changes in negative symptoms and EEG in schizophrenic patients after repetitive Transcranial Magnetic Stimulation (rTMS): an open-label pilot study

Summary. The effects of repetitive transcranial magnetic stimulation (rTMS) on schizophrenic negative symptoms (NS) and EEG topography were investigated in this pilot study.10 patients with predominant NS were treated with 10Hz rTMS over the left dorsolateral prefrontal cortex for 5 days. For NS ratings, the Scale for the Assessment of Negative Symptoms (SANS) was used. Both ratings and EEG recordings were obtained pre- and post-rTMS. Electrical activity changes were computed by Low Resolution Brain Electromagnetic Tomography.SANS showed an improvement after rTMS, from 49.0 (SD: 10.7) to 44.7 (SD: 11.8) (means). EEG frequency bands were changed fronto-temporally (right) and were mainly decreases in delta- and beta- and increases in alpha1-activity, as well as decreases in beta-activity in the temporal and parieto-occipital regions (left).Although we are aware of the limitations of this study, we assume a slight improvement in NS. The EEG findings refer to a possible neurophysiologic correlate of their improvement after rTMS.     

5-Hydroxytryptamine activates a barium-sensitive, cAMP-mediated potassium conductance in the leech giant glial cell

5-Hydroxytryptamine (5-HT), a neurotransmitter and neuromodulator in the central nervous system of the leech Hirudo medicinalis hyperpolarizes the giant glial cell in the neuropil of segmental ganglia at micromolar concentrations. The 5-HT-evoked glial response (EC(50) approximately 2.5 microM) is mediated by a non-desensitizing, G-protein-coupled receptor and due to activation of a Ca(2+)-independent K(+) conductance. The adenylyl cyclase inhibitor SQ22,536 blocks the response to 5-HT; in the presence of 1 mM db-cAMP, but not of 1 mM db-cGMP, the glial response is suppressed. The 5-HT-evoked response is reduced by Ba(2+) with half-maximal inhibition at 50 microM Ba(2+). The results suggest that release of 5-HT from serotonergic neurons, or the maintenance of micromolar levels of extracellular 5-HT in the ganglion, may help to set the glial membrane potential close to the K(+) equilibrium potential.     

Functional activation imaging in aging and dementia

With life expectancy increasing continuously, the effects of neurodegeneration on brain function are a topic of ever increasing importance. Thus there is a need for tools and models that probe both the functional consequences of neurodegenerative processes and compensatory mechanisms that might occur. As neurodegenerative burden and compensatory mechanisms may change over time, these tools will ideally be applied multiple times over the lifespan. Specifically, in order to elucidate whether brain-activation patterns in Alzheimer's disease (AD) and in healthy aging follow general rules in the context of degeneration and compensation, it is necessary to compare functional brain-activation patterns during different states of neurodegeneration. This article integrates the findings of functional activation studies at different stages of neurodegeneration: in healthy aging, in subjects at high risk of developing dementia, in subjects with mild cognitive impairment (MCI), and in patients suffering from AD. We review existing theoretical models that aim to explain the underlying mechanisms of functional activation changes in aging and dementia, and we propose an integrative account, which allows for different neural response patterns depending on the amount of neuronal damage and the recruitment of compensatory pathways.     

Cervical immunoglobulin A and altered vaginal flora in pregnant women with threatened preterm delivery

The aim of our study was to investigate the cervical immunoglobulin A concentration in women with threatened preterm delivery. Immunoglobulin A concentration in the cervical mucus of 80 women with symptoms of preterm delivery was measured using radial immunodiffusion. The results were compared with those of 60 healthy pregnant women. Concentrations of immunoglobulins in maternal serum were also measured. There was no significant difference of cervical immunoglobulin A (IgA) concentration between women with threatened preterm delivery and controls: 53.98 (0.0-189.7) mg/l vs. 61.7 (1.4-400.9; p<0.4) mg/l (median, range). The median of cervical IgA levels in the group of threatened preterm delivery did not differ significantly between patients delivered preterm (n=34) or at term (n=46): 38.3 (0.0-187.9) vs. 65.7 (1.4-189.7; p<0.2) mg/l. Women with a normal vaginal flora showed a significantly higher cervical IgA concentration than those with a pathological colonization: 72.7 (0.0-187.9) vs. 42.5 (0.0-189.7) mg/l. Patients with a pathological vaginal smear and preterm delivery had the lowest IgA levels (35.0; 0.0-187.9 mg/l). Measurement of cervical IgA concentration does not differentiate between women who deliver before or at term.     

Quality of life of living kidney donors in Germany: a survey with the Validated Short Form-36 and Giessen Subjective Complaints List-24 questionnaires

BACKGROUND: Most studies evaluating the impact of kidney donation on donors' quality of life (QOL) have limitations such as small cohort size, unmatched references, use of nonstandardized and nonvalidated questionnaires, or low response rates. METHODS: We performed a study on donors' QOL that was designed to avoid these limitations. All available living renal donors in our department in the last 18 years were included in the study. QOL was assessed with two validated, standardized questionnaires (Short Form-36, Giessen Subjective Complaints List [Giessener Beschwerdebogen]-24) and compared with gender- and age-matched references. In addition, specific questions relating to kidney donation were asked. RESULTS: The response rate (89.8%) is one of the highest reported for studies on QOL of living kidney donors. Most donors had an equal or better QOL than the healthy population. Donors' willingness to donate again (93.4%) or recommend living-donor kidney transplantation (92.4%) was high, irrespective of complications. A small number of donors experienced financial drawbacks or occupational disadvantages. Donors aged 31 to 40 years were found to be at risk of QOL deterioration after organ donation. Donor and recipient complications had a significant impact on donors' QOL. One third of the donors found that the psychologic care preceding and after kidney donation was insufficient. CONCLUSIONS: Our findings support the practice of living-donor kidney transplantation as a good means to meet the persisting organ shortage. Further effort must be put into minimizing donor and recipient complications. The specific demands of younger donors should be further elucidated. In addition to medical follow-up, living kidney donors should also be offered lifelong psychologic counseling.     

Laparoscopic radical prostatectomy: is intact organ removal attainable? Study of margin status

PURPOSE: To determine the initial oncologic results (pathology) of specimens removed by laparoscopic radical prostatectomy (LRP) by examining the surgical margins. PATIENTS AND METHODS: The 70 consecutive LRP procedures performed for clinically localized prostate cancer at Eastern Virginia Medical School from April 2001 to November 2002 were reviewed for preoperative and important intraoperative variables. The initial histopathology report and a prospective review by a single genitourinary pathologist for margin status as well parenchymal exposure of benign glands were assessed. Postoperative prostate specific antigen (PSA) levels were noted. RESULTS: The clinical stage distribution was as follows: T1c = 59, T2a = 10, and T2b = 1. The preoperative median PSA value was 6.96 ng/mL. The mean operative time was 307 minutes. The mean estimated blood loss was 298 mL. The prospective pathologic review results were as follows: 1 pT0 (1.4%), 60 pT2 (85.7%), and 9 pT3 (12.8%). The overall positive surgical-margin rate was 15.7%. Of those patients with pT2 disease; 8 specimens (13.3%) had a positive margin, whereas 33% of patients with pT3 disease had a positive surgical margin. Parenchymal exposure of benign glands on the inked surface was recognized in 8 patients (13.3%). Data from PSA assays 1 month postoperatively were available in 69 patients. Serum PSA was undetectable (< or =0.1 ng/mL) in 67 men (97%). CONCLUSION: An LRP can offer surgical margins comparable to those of open procedures series reported in the literature. Long-term progression and survival outcome data are necessary before this procedure should be offered as a replacement for open prostatectomy.