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J Stamm

Publications and source records attributed to J Stamm.

17 recordsLinked to original sources
PubMed1994

Task-induced differential cortical activation pattern.

Measures of task-dependent cortical activation were assessed by bilateral EEG recordings from frontal, temporal, parietal and occipital areas. Two pictorial tests, the Raven Advanced Progressive Matrices and the Space Relations Test were used for verbal and spatial conditions, respectively. Recordings were obtained for 20 trials of each task from 22 right-handed adult males and 16 s. trial epochs were subjected to Fast Fourier analyses. Averaged intensity values for the alpha band were compared between verbal and spatial tasks for all subjects and between subgroups of verbalizers and visualizers, allotted on the basis of subject's performance index, derived from response speed and accuracy on the two tasks. The results were as follows: (1) The most pronounced EEG discriminators between the two performance subgroups are the left and right parietal and the right frontal area; (2) The left parietal zone provides the most pronounced discrimination between two groups; (3) There were significant interactions between the left parietal and the right frontal region; (4) The two parietal areas show characteristic frequency shifts in opposite directions for the task conditions. The findings imply complex interplay among the two parietal and right frontal areas, associated with sequential and holistic strategies. The results urge researchers to take into consideration subjectively preferred cognitive strategy, which along with objective task demands influences the process of problem solving and accompanying physiological changes.

Adult↗
PubMed1994

Effect of peritoneal fluid supplemented with exogenous progesterone on sperm motility in vitro.

Since progesterone has been claimed to induce acrosomal reaction and hyperactivated motility of human spermatozoa, the present study was undertaken to determine if its presence at concentrations similar to those of peri-ovulatory follicular fluid could influence the effect of peritoneal fluid on sperm motility in vitro. To this end, 11 sperm samples were incubated at 37 degrees C with five peritoneal fluids with/without exogenous progesterone, and sperm motility was assessed using a computer-assisted analyser at time (t) = 0, 2.5, 5 and 24 h. Overall there was no observable constant trend for enhancement or inhibition of sperm motility. Progesterone generally induced a negative effect on those sperm samples with high velocities in the native peritoneal fluids and a positive effect on those sperm samples demonstrating low motility in the native peritoneal fluids. The incorporation of progesterone into the incubation medium seemed to result in a 'tuning' of sperm velocity to around 30-50 micron/s. However, a given sperm sample reacted differently when incubated with various peritoneal fluids and, reciprocally, different semen samples incubated with the same peritoneal fluid showed very variable motility patterns. The greater variability of the effects exerted by progesterone on sperm motility could arise from the fact that each sperm sample may contain subpopulations of gametes with different sensitivity to progesterone.

Adult↗
PubMed1992

Effect of volumetric mixtures of peritoneal and follicular fluid from the same woman on sperm motility and acrosomal reactivity in vitro.

OBJECTIVE: To study the effect of peritoneal (PF) and follicular fluids (FF from the same woman) as well as of given volumetric combinations thereof on sperm motility and acrosomal reactivity. DESIGN: Prospective. Peritoneal fluid and FF were incubated separately or in given volumetric combinations (PF/FF = 100/0, 75/25, 50/50, 25/75, 0/100; vol/vol) with swim-up sperm suspensions. SETTING: In vitro fertilization and general infertility clinic and laboratories. PATIENTS, PARTICIPANTS: Women participants of the gamete intrafallopian transfer program (motility study, n = 20; acrosomal reaction study, n = 14). Sperm donors of the artificial insemination program and men with given sperm parameters. INTERVENTIONS: Hormonal stimulation. Laparoscopy. MAIN OUTCOME MEASURES: Progressive velocity and percentage of motile gametes measured with multiple-exposure photography. Acrosomal reactivity measured by an immunofluorescent technique. RESULTS: Follicular fluid always influenced progressive motility and also sustained the number of motile gametes, as function of time, better than PF or the PF/FF mixtures (P less than 0.05). The acrosomal reactivity of sperm incubated in the various PF/FF combinations was low; after 5 hours only the FF-sperm suspensions showed a significant enhancement of acrosomally reacted gametes. CONCLUSION: At ovulation, FF transmit positive (motility- and acrosomal reactivity-enhancing) signals to sperm, whereas PF may transmit positive, neutral, or negative signals (noise signals). The volumetric combination of FF and PF in the tubal environment, which may differ from cycle to cycle and from woman to woman, could therefore result in synergic (or antagonistic) effects on the sperm fertility potential.

Acrosome↗
PubMed1990

Excerpts from presentation on epidemiologic data and changing demographics.

Dental surveys provide epidemiologic and sociodemographic data useful for program planning, implementation, and evaluation. Dental public health decisions in North Carolina have been based on statewide oral health surveys. Results from the 1986-87 North Carolina School Oral Health Survey and a comparison of these data to previous survey results and to recent national estimates of oral disease provide a basis for the discussions and deliberations during the symposium.

Adolescent↗
PubMed1987

The role of adjunctive Rodogyl therapy in the treatment of advanced periodontal disease. A longitudinal clinical and microbiologic study.

Several studies have indicated that the combination of metronidazole and spiramycin is synergistic against anaerobic bacteria and may be effective against oral infections. The present study sought to determine the efficacy and safety of a commercial preparation of these two antibiotics (Rodogyl) when used adjunctively in the treatment of advanced periodontal disease. In a double-blind parallel randomized trial, 56 patients (mean age = 44 years) with advanced periodontitis (50 of whom completed the study) were assigned to either the Rodogyl or placebo group. Both groups were thoroughly scaled and root planned for approximately 6 hours, with one group receiving Rodogyl for 2 weeks and the other a placebo. No other therapy was received during the study period. Two sites in each patient with probing depths of at least 7 mm were selected for study. Plaque level (P1I), gingival inflammation (GI), probing depth (PD), and attachment level (AL) were measured at baseline, 14 days, 1 month, and then at monthly intervals up to 6 months. Subgingival bacteria were monitored with dark-field microscopy. The development of resistant bacteria, as well as side effects to the medications, was also monitored. The Rodogyl group exhibited a greater gain in AL (0.67 mm) from the 2-month interval until the end of the study. Although this difference was statistically significant (P less than 0.05), it was not necessarily of biologic significance. There was a significantly greater decline in the proportion of spirochetes in the Rodogyl group at the 14-day interval, and this difference remained significant (P less than 0.05) at all study intervals. No difference in the proportion of motile organisms was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Cerclage by the abdominal route].

The authors, having carried out two cerclage operations through the abdominal route for cervico-isthmic incompetence, review the literature and assess the advantages and disadvantages of this method. This surgical technique makes it possible to put the stitch exactly at the level that is needed. It can be carried out when the cervix is very short, effaced or totally distorted. The results that have been obtained in the larger series are striking: the percentage of infants that survived before the operation was between 10.4% and 24% and after the operation between 70% and 95%. The complications described in the literature have been rare: haemorrhage from damage to the veins at the time of the operation: fetal death in the days after the stitch had been placed badly so that the uterine vessels were occluded. As far as we know, there has never been a case of infection.

Abdomen↗
PubMed1983

[The peritoneal sperm migration test (PSM-test) following fractional artificial insemination during laparoscopic fertility testing].

The peritoneal sperm migration test following fractional artificial insemination during diagnostic laparoscopy was carried out in the context of fertility investigation in 78 women age 25 to age 40. 35 cases had a positive PSM test, 43 had a negative PSM test. The results were correlated to the phase of menstrual cycle, the semen analysis and the tubal patency test. The test showed the best results when it was done in the preovulatory phase in conjunction with a normal semen analysis and a normal tubal patency test. In 2 cases with severe oligospermia and in two cases with bilateral tubal occlusion the test was still positive. The test is of clinical importance and can be done without increased risk during any laparoscopy for infertility. Valuable conclusion about the migration of sperms through the uterus and the tubes in the individual couple can be obtained. This is of prognostic importance. The test shows in addition to mechanical tubal patency by chromopertubation the functional or physiologic tubal permeability. Negative PSM tests are relatively frequent and are caused by tubal, uterine or sperm factors.

Adult↗
PubMed1982

Spontaneous cortical slow-potential shifts and choice reaction time performance.

EEGs from Fz, Cz and Pz locations (reference--right mastoid) were obtained from 36 adults. For experimental trials the Fz slow potentials (SP) were determined for a pretask interval of: a 3 sec baseline, followed by a 2.5 sec SP shift, in either negative (3.5 microV) or positive (1.5 microV) direction, and maintenance at this level for another 2.5 sec. When this criterion was met the stimuli for a choice RT task were presented (potential-related event, PRE), which required a button-press response with the right or left hand for differing stimulus configurations. During subsequent control sessions subjects were tested without pretask criterion SP shifts, with yoked pretask intervals from the experimental sessions. For the experimental conditions the mean RTs were significantly faster and less variable with the negative than with the positive SP shift condition. For the control conditions mean RTs were somewhat faster for the positive than for the negative criterion, which might be attributed to the more variable pretask intervals during the latter polarity condition. For confirmation of the cortical localization of this effect, the experimental session was replicated with corresponding negative and positive SP shift criteria from Pz. No significant differences among means and standard deviations of RTs were found. SP shifts from criterion electrodes (Fz or Pz) were significantly greater in mean amplitude than the concomitant SP shifts from the other electrodes. The present findings demonstrate the feasibility of the PRE methodology for investigations of human brain functions.

Adult↗
PubMedDate not supplied

Influence of peritoneal fluid from spontaneous and stimulated cycles on sperm motility in vitro.

Peritoneal fluids (PFs) from spontaneous (n = 14) and gonadotrophin-stimulated cycles (n = 20) were obtained during diagnostic laparoscopy and gamete intrafallopian transfer (GIFT) procedures, respectively. The effects of these fluids on the linear component of sperm motility and on the percentage of motile spermatozoa were studied in vitro by objective motility assessments and compared to a control medium (B2-Ménézo). Overall, the two types of PFs were found to have rather similar effects on the motility parameters studied. However, the fluids from hormonally-stimulated cycles sustained motility better (i.e., sperm velocity and percentage of motile sperm) and in a rather constant manner as a function of time (narrower range distributions of the motility measurements). Furthermore, it was observed that under identical experimental conditions motility measurements depended not only on the type of PF used but also on the sperm sample. These results suggest that assisted reproduction procedures in which PF is the medium where the gametes eventually meet and interact, such as direct peritoneal insemination (DIPI) or peritoneal oocyte and sperm transfer (POST), could have different success rates if performed in spontaneous rather than in stimulated cycles. At the same time, our results may help to explain why different pregnancy rates were reported in different studies using DIP or POST.

Adult↗
PubMedDate not supplied

Bacteroides ureolyticus in men consulting for infertility.

A screening of 3196 semen analyses performed in our clinic from January 1986 to December 1990 revealed 314 (9.8%) patients whose semen was infected with Bacteroides ureolyticus. Investigating the relationship between the presence of B. ureolyticus, the seminal microflora and the conventional semen parameters, we observed that the presence of this micro-organism in the semen was coupled (1) to an increased presence of Enterococcus species, (2) to an increased number of short-tailed spermatozoa and epithelial cells, and (3) to a decreased total fructose concentration (mg ejaculate-1). These results suggest that B. ureolyticus or its toxins may influence sperm morphology and function by yet unknown mechanisms and may also increase the number of epithelial cells by soft tissue infection in vivo. The decreased fructose levels suggest that this anaerobic micro-organism might specifically colonize the seminal vesicles, while the normal zinc values recorded suggest a normal prostatic function. Overall, our data support the hypothesis that the presence of B. ureolyticus is not associated with nongonococcal urethritis.

Bacteria, Aerobic↗
PubMedDate not supplied

Computer-aided semen analysis: sperm concentration assessment by the Strömberg-Mika system.

The scope of this study was to evaluate the accuracy, precision and specificity of the sperm concentration measurements by the Strömberg-Mika Cell Motion Analyser (SM-CMA). Our data show that the instrument generally underscores the sperm concentration and therefore the uncorrected measurements must be corrected by the operator using the 'mouse'-driven option. In terms of precision, the system appears to have an excellent internal precision whereas its repeatability is influenced by the sperm concentration, the sample's homogeneity and the correction of the raw data. In order to increase the system's repeatability, we suggest that sperm counts should be carried out in various fields of the counting chamber, and the mean of the corrected values be taken as representative of the sperm concentration in the ejaculate if the various measurements show a homogeneous (poissonian) distribution. The correction of the raw data with the 'mouse'-driven correction option was also shown to improve the system's reproducibility. Concerning specificity, our data evidenced that, without technical correction, the instrument failed to correctly classify certain spermatozoa as such, thereby grossly underscoring sperm counts. This finding was more evident at low sperm counts. Overall, the SM-CMA requires additional laboratory time but the corrected sperm counts are comparable to manual counts and semi-automated counts with the added option that it provides the andrologists with various motility characteristics not possible with the latter methodologies.

Autoanalysis↗