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Biomedical subjects

J Weiss

Publications and source records attributed to J Weiss.

At least 307 records · Page 17Linked to original sources
PubMed1988

Median and radial sensory latencies to digit I as compared with other screening tests in carpal tunnel syndrome.

Fifty two patients with suspected carpal tunnel syndrome were evaluated electrodiagnostically by using a variety of screening tests. The criteria of normalcy were as follows: distal median motor latency lower than 4.2 ms, distal median sensory latency wrist-to-third finger at 14 cm higher than 3.2 ms for the onset and than 3.8 ms to the peak, median sensory conduction velocity wrist-to-palm at 7 cm higher than 40 m/s peak-to-peak and difference between median and radial sensory latencies wrist-to-first digit at 11 cm using an intermediate position as site of stimulation and measured peak-to-peak ("bactrian sign") higher than 0.4 ms. Other tests such as median-ulnar comparison using finger 4 were considered less reliable based primarily on the frequent association of carpal tunnel syndrome and Guyon canal entrapment. Carpal tunnel syndrome was confirmed in 49 of 52 suspected cases (94.2%) by at least one abnormal screening test. Bilateral involvement was noted in 65.3% of the cases (32 patients). The "bactrian" (two-hump camels) sign was the single most sensitive test used, being positive in 83.7% of cases. The second most sensitive test was median SNAP (wrist-to-finger) latency and the third, sensory conduction velocity across the carpal tunnel.

Adult↗
PubMed1988

Effects of the bactericidal/permeability-increasing protein of polymorphonuclear leukocytes on isolated bacterial cytoplasmic membrane vesicles.

The bactericidal/permeability-increasing protein (BPI) of polymorphonuclear leukocytes is a potent bactericidal agent specific for gram-negative bacteria. The protein blocks bacterial multiplication without substantially inhibiting the uptake and incorporation of macromolecular precursors, suggesting that the cytoplasmic membrane escapes early injury. Because greater than 90% of bound BPI can be removed from the bacterial surface sites after irreversible loss of viability, it was uncertain whether BPI reaches the cytoplasmic membrane and, if so, affects its functions. This study shows that BPI caused similar dose-dependent inhibition of O2 consumption and metabolic energy-dependent amino acid transport by cytoplasmic membrane vesicles of both gram-negative (Escherichia coli) and gram-positive (Bacillus subtilis) bacteria. Near maximal inhibition occurred at BPI doses that caused complete killing of an equivalent number of intact E. coli, with binding of BPI to membrane vesicles that was less than or equal to 10% of binding to intact (BPI-sensitive) bacteria. The effects of BPI and of the membrane-disruptive peptide antibiotic polymyxin B on membrane vesicles were distinctly different, indicating that the two agents affect membrane function by different mechanisms. BPI also rapidly inhibited O2 consumption by intact E. coli, with minimal impairment of bacterial protein synthesis. Thus, BPI is capable of damaging the cytoplasmic membrane of both gram-negative and gram-positive bacteria and of inhibiting at least one cytoplasmic membrane-associated function in intact E. coli. The relationship between these effects and the mechanism of bacterial killing by BPI remains to be established.

Amino Acids↗
PubMed1988

Detection of fungi in tissue sections by lectin histochemistry.

A battery of 21 fluoresceinated lectins was tested on sections of paraffin-embedded human tissues to determine which lectin could be used in the microscopic diagnosis of fungal diseases. Three lectins, from Canavalia ensiformis (concanavalin), Triticum vulgare (wheat germ A), and Phytolacca americana (pokeweed [PWM]), were found to react with fungal pathogens commonly encountered in nosocomial infections. Best results were obtained with PWM and succinylated wheat germ A, which, due to their weak reactivity with normal tissues, reacted almost selectively with fungi.

Fluorescein-5-isothiocyanate↗
PubMed1988

Faulty sternotomy and complications after median sternotomy.

In 11 of 55 patients with complications of median sternotomy, a paramedian sternotomy has been detected by computed tomography or at reparative operation. The thin side of the sternum is easily broken by the closing wires, this being the cause of instability and probably dehiscence and consequent infection and osteomyelitis. Most of the 11 patients in this group had some other predisposing risk factors, such as obesity, prolonged aortic cross-clamp time, and prolonged respiratory assistance. We suggest that, if a paramedian sternotomy is diagnosed at the primary operation, special closure techniques should be undertaken. Each patient with early dehiscence of a median sternotomy should undergo a computed tomographic examination. If a paramedian sternotomy is proved, simple reclosure is inadvisable. Sternectomy and closure with muscle flaps are then indicated.

Humans↗
PubMed1988

Testing hypotheses about unconscious mental functioning.

Three research studies were designed to test the explanatory powers of two broad psychoanalytic hypotheses about the nature of unconscious mental functionings. Both hypotheses bear directly on the psychoanalytic theory of therapy. The first, the Dynamic hypothesis, assumes that unconscious mental life is determined by the dynamic interactions of unconscious forces that take place in accordance with the pleasure principle beyond the patient's control. The second, the Unconscious Control hypothesis, while not excluding unconscious dynamic interactions, assumes that the patient unconsciously may use his higher mental functions and that he exerts a certain degree of control over his unconscious mental life. He uses this control to develop goals, to test the therapist (and at the same time his pathogenic beliefs), and to regulate the coming forth of repressed mental contents, bringing them forth when he unconsciously decides that he could safely experience them. The studies demonstrate that quantitative, reliable research methods can be used to test basic psychoanalytic hypotheses about the nature of unconscious mental functioning. The findings are compatible with the Unconscious Control hypothesis as described above.

Adult↗
PubMed1987

A 25-kDa NH2-terminal fragment carries all the antibacterial activities of the human neutrophil 60-kDa bactericidal/permeability-increasing protein.

We have isolated, after limited proteolysis of the bactericidal/permeability-increasing protein (BPI) of human neutrophils, a 25-kDa fragment that possesses the bactericidal and envelope-altering activities of the 60-kDa parent protein. On a molar basis, the fragment is as potent as holo-human BPI against rough Escherichia coli, is more potent than holo-BPI against more resistant smooth E. coli, and retains the specificity of BPI toward Gram-negative bacteria. NH2-terminal amino acid sequence analysis shows that the fragment is derived from the NH2 terminus of the BPI molecule. These findings suggest that all of the molecular determinants of the antibacterial properties of BPI reside within the NH2-terminal 25-kDa segment, implying a novel structural/functional organization for a cytotoxic protein.

Amino Acid Sequence↗
PubMed1987

Relation between binding and the action of phospholipases A2 on Escherichia coli exposed to the bactericidal/permeability-increasing protein of neutrophils.

Exposure of Escherichia coli to the bactericidal/permeability-increasing protein (BPI) of neutrophils renders the bacterial phospholipids susceptible to hydrolysis by only a few of numerous phospholipases A2 tested. To explore further the determinants of hydrolysis we measured the binding of 125I-labeled phospholipase A2 to E. coli in the presence and absence of BPI. Phospholipases A2 from Aqkistrodon piscivorus piscivorus venom and pig pancreas neither degraded nor bound to BPI-treated E. coli. In contrast, the phospholipases A2 from Aqkistrodon halys blomhoffii and Aqkistrodon halys palas venoms actively hydrolyzed the phospholipids of BPI-treated E. coli: they also bound to E. coli in the presence but not in the absence of BPI. Carbamylation of lysines of the A.h. blomhoffii phospholipase A2 progressively reduced binding in parallel with reduced phospholipid hydrolysis. Both binding and hydrolysis increased with increasing BPI dose. However, maximal binding occurred at 25% of the BPI dose that produced optimal hydrolysis. Thus, binding may be necessary but is not sufficient for maximal BPI-mediated phospholipid hydrolysis. Comparison of the NH2-terminal amino sequences of the active and inactive phospholipase A2 suggests that this portion of the phospholipase A2 molecule plays a role in BPI-independent binding and hydrolysis.

Antimicrobial Cationic Peptides↗
PubMed1987

Limitations of bipolar and unipolar conditioning stimuli for inhibition in the human heart.

Noncapturing, conditioning electrical stimuli (Sc) delivered within the ventricular refractory period can prolong refractoriness and prevent later stimuli from eliciting a propagated response (inhibition). The purpose of this study was to further define the spatial effects of Sc, to determine if the effects of Sc can be enhanced by the use of unipolar as opposed to bipolar stimulation, and to evaluate the effect of Sc on the physiologic spread of excitation during atrioventricular reentry tachycardia. In 23 patients the right ventricular refractory period was determined before and after the introduction of bipolar, unipolar cathodal, and unipolar anodal noncapturing Sc with pulse widths of 2 or 9 msec and strengths of twice diastolic threshold and 10 MA. Pacing and conditioning stimuli were delivered at the same site and at sites separated by 3 mm. During ventricular pacing both bipolar and unipolar Sc prolonged the ventricular refractory period by greater than or equal to 10 msec in 22 of 23 patients when both Sc and pacing stimuli were delivered to the same site. However, when Sc was delivered 3 mm away from the pacing stimuli, the ventricular refractory period increased by greater than or equal to 10 msec in only 1 of 17 patients who received bipolar Sc and in none of 13 patients who received unipolar Sc. In seven patients bipolar conditioning stimuli were delivered as close as possible to the atrial insertion of an accessory atrioventricular connection during circus movement tachycardia with a well-localized accessory pathway. Sc did not terminate or slow tachycardia in any patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Male rat behavior, endocrinology and reproductive physiology in a mixed-sex, socially stressful colony.

Previous research suggests that social stress in the absence of females disrupts male reproductive functioning. The presence of females often increases intermale aggression and, presumably, the probability that fighting----social stress----hyperadrenalism----reproductive disruption. Colony membership of male rats was manipulated in the present research to provoke high or low aggression and the consequent environments that were characterized as high or low socially stressful. The principle comparisons were between all-male and mixed-sex colonies. Results were that the presence of females predictably increased aggressive behavior in both high and low stress environments, yet the adrenal response was different in the two environments. When females were present, adrenal weights and circulating corticosterone levels of males increased in the low stress setting but decreased in the high stress setting. Males cohabitating with females in both environments, on the other hand, experienced elevated titers of circulating testosterone, increased activity of various androgen-sensitive tissues and greater epididymal sperm reserves. The conclusion is that the profound changes in males with sexual contact can attenuate the stress----reproductive disruption relationship.

Adrenal Glands↗
PubMed1987

Harman induces preference for ethanol in rats: is the effect specific for ethanol?

Increasing concentrations of either ethanol, etonitazene, clomethiazole or midazolam were offered to male Wistar rats for 21 days. Between day 8 and day 21, the animals were treated with several doses of harman, harmalan, and tetrahydronorharman (tetrahydro-beta-carboline) by means of continuous intraventricular infusion. Harman and THN induced a significant preference for ethanol in a dose-dependent manner. Harman was approximately three times more potent than THN. The amount of ethanol consumed during the second and third weeks of the experimental period correlated with the harman concentration in the brain after the cessation of the treatment (p less than 0.01). Harman infusion attenuated the clomethiazole intake, whereas that of etonitazene and midazolam was not affected as compared with CSF-treated rats. By counting licking movements, it was found that the rats drank ethanol and water at distinct time periods with the pattern dependent on the concentration of the ethanol solution offered. The intervals between the maxima were 6 to 8 hours at low ethanol concentrations. Relatively high concentrations caused a disruption of the regular rhythms in favour of shorter ones with increasing intervals between the maxima (3 hr, 4 hr, 5 hr intervals). Harman treatment (27 nmol/hr) disturbed the regular rhythms at lower ethanol concentrations but mimicked the ultradian rhythm which was observed at high ethanol concentrations in CSF-treated animals. The observed coincidence of water and ethanol intake was uncoupled if the highest ethanol concentration in both treatments was offered. Thus, treatment with harman changed the rhythm of fluid intake in a direction which was detected in CSF-treated rats only at relatively high ethanol concentrations.

Activity Cycles↗
PubMed1987

Enhancement of conduction in an accessory pathway by local noncaptured stimuli.

Subthreshold stimuli have been reported to prolong the refractory period of myocardial tissue. This report presents the first case of reproducible acceleration of a reentrant tachycardia by apparently subthreshold stimuli delivered to the os of the coronary sinus during the atrial refractory period in a child with incessant orthodromic tachycardia utilizing a posteroseptal pathway. Mechanisms by which these stimuli could influence the tachycardia circuit are proposed, and the potential usefulness of this finding for mapping tachyarrhythmias is discussed.

Cardiac Pacing, Artificial↗